WO2017049470A1

WO2017049470A1 - Prodrugs of gamma-hydroxybutyric acid, compositions and uses thereof

Info

Publication number: WO2017049470A1
Application number: PCT/CN2015/090326
Authority: WO
Inventors: Jia-Ning Xiang; Xuesong Xu; Xuan Zhang
Original assignee: XW Laboratories Inc Cayman Islands
Current assignee: XWPharma Ltd
Priority date: 2015-09-23
Filing date: 2015-09-23
Publication date: 2017-03-30
Anticipated expiration: 2018-03-23

Abstract

The present application discloses prodrugs of gamma-hydroxybutyric acid as well as compositions and uses thereof.

Description

PRODRUGS OF GAMMA-HYDROXYBUTYRIC ACID, COMPOSITIONS AND USES THEREOF

________________________________________________________________________

FIELD OF THE INVENTION

The present application generally relates to prodrugs of gamma-hydroxybutyric acid, as well as compositions and uses thereof.

BACKGROUND OF THE INVENTION

Narcolepsy is a chronic neurological disorder characterized by excessive daytime sleepiness (EDS) , cataplexy, sleep paralysis, hypnagogic hallucinations, and disturbed nocturnal sleep. EDS is usually present and appears first. Cataplexy occurs in approximately 70％ of patients with narcolepsy while the other symptoms feature less frequently and in various combinations. The prevalence of narcolepsy in the United States and Europe ranges from 20 to 67 per 100,000.

Gamma-hydroxybutyric acid (GHB) is a naturally-occurring central nervous system transmitter. The GHB sodium salt also called sodium oxybate, currently being marketed by Jazz Pharmaceuticals plc as Xyrem, is the first and only drug approved by the U.S. Food and Drug Administration (FDA) to treat cataplexy associated with narcolepsy. Sodium oxybate has been shown to be highly efficacious with a～70％ reduction of the total number of cataplexy episodes. In Europe, sodium oxybate is used medicinally for various purposes including narcolepsy, alcohol dependence, and opiate dependence. In November 2005, the FDA approved an expanded indication for sodium oxybate as a treatment for excessive daytime sleepiness (EDS) . In addition, sodium oxybate has also been conducted in the clinical trial in the U.S. for fibromyalgia syndrome, a pain of fibromyalgia that is notoriously difficult to treat. Sodium oxybate also has potential to treat other CNS disorders such as insomnia, hallucinogenic dreams and sleep paralysis.

Despite its efficacious effect and advantageous position in treating EDS and cataplexy associated with narcolepsy, sodium oxybate displays a sub-optimal pharmacokinetics profile that makes it difficult to provide optimal absorption and predictable sustained plasma levels of drug. Currently commercially available formulation of sodium oxybate is an oral solution, and is dosed twice per night, with bioavailability of approximately 25％. Its half life is about 20-23 minutes in healthy volunteers and about 53 minutes in narcoleptic patients. The pharmacokinetics deficiencies of sodium oxybate include: 1) low bioavailability for an oral drug； 2) unpredictable drug plasma concentrations resulting from its erratic absorption property in patients； 3) short plasma half-life (t_1/2 < 1 hr) ； 4) food intake impact (high fat meal may significantly delay and decrease absorption of sodium oxybate) ； 5) patients need to take sodium oxybate twice (2-4 hours apart) in the evening before sleeping to avoid any side effects brought by a single high dose； 6) poor patient compliance and inconvenient drug administration (due to the twice per night dosage regimen) . Consequently, these deficiencies prevent sodium oxybate from providing the maximum therapeutic benefit that it can possibly achieve. Therefore, there remains a continuing need for compounds derived from GHB to overcome some or all of the above described deficiencies.

SUMMARY OF THE INVENTION

The present application provides, inter alia, a compound of Formula I:

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein the variables are defined below.

The present application further provides a pharmaceutical composition comprising one or more compounds of the invention.

The present application also provides use of one or more compounds of the invention in the manufacture of a medicament for treating a disease, wherein the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophrenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease.

The present application further provides a method of treating a disease, comprising administering to a subject an effective amount of one or more compounds of the invention, wherein the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophrenia, Binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease.

The present application also provides a compound of the invention for use in any of the methods described herein.

DETAILED DESCRIPTION OF THE INVENTION

Compound

In one aspect, the present application provides a compound of Formula I:

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

B is- (O) R¹, -R² (OCO) R³, substituted or unsubstituted C_5-10 aryl, C_1-12 alkyl, C_5-12 aralkyl, C_2-12 alkenyl, C_6-12 aralkenyl, C_2-12 alkynyl, C_3-8 cycloalkyl, 3-10 membered heterocyclic alkyl, or 5-10 membered heterocyclic aryl, wherein the one or more substituents are selected from the group consisting of-R⁴-S-R⁵, halogen, hydroxyl, cyano, amino, substituted amino, amino protection group, mono-, di-or tri-halo-C_1-6 alkyl, C_1-12 alkyl, C_2-12 alkenyl, C_2-12 alkynyl, C_1-12 alkoxy, C_5-10 aryl, C_3-8 cycloalkyl, C_1-12 alkylsulfonyl, 3-8 membered heterocyclic alkyl, 3-10 membered heterocyclic aryl, C_5-10 aryloxyl, C_5-10 arylcarbonyl, C_1-6 alkylcarbonyloxyl or C_1-4 alkyloxycarbonyl；

wherein

R¹ and R³ are independently hydrogen, C_1-12 alkyl, C_2-12 alkenyl, C_5-12 aralkyl, C_6-12 aralkenyl, C_2-12 alkynyl, C_5-10 aryl, C_3-8 cycloalkyl, 3-10 membered heterocyclic alkyl, or 5-10 membered heterocyclic aryl, which can be optionally mono-or independently multi-substituted by-R⁴-S-R⁵, halogen, hydroxyl, cyano, amino, substituted amino, C_1-12 alkyl, C_2- ₁₂ alkenyl, C_2-12 alkynyl, C_5-10 aryl, C_1-12 alkoxy, C_3-8 cycloalkyl, 3-8 membered heterocyclic alkyl, or 3-10 membered heterocyclic aryl, C_1-4 alkylsulfonyl, C_5-10 aryloxyl, C_5-10 arylcarbonyl or C_1-4 alkyloxycarbonyl；

R² is C_1-6 alkyl；

R⁴ is a bond, C_1-6 alkyl, C_5-10 aryl, or C_5-12 aralkyl, and R⁵ is hydrogen or C_1-12 alkyl.

In some embodiments, B is C_1-8 alkyl substituted with C_2-6 alkyl, aryl or amino group and B is not linear alkyl. In some embodiments, B is C_2-6 alkenyl substituted with C_1-6 alkyl, aryl or amino group. In some embodiments, B is substituted or unsubstituted C_3-8 cycloalkyl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl. In some embodiments, B is substituted or unsubstituted 3-8 membered heterocyclic alkyl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl. In some embodiments, B is substituted or unsubstituted 5-8 membered heterocyclic aryl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl.

In some embodiments, B is–CHR₆R₇, wherein R₆ and R₇ are independently selected from the group consisting of hydrogen, C_2-6 alkyl, C_5-10 aryl and amino group. In some embodiments, R₆ and R₇ can be cyclized to form a C_3-8 cycloalkyl. In some embodiments, R₆ and R₇ together with a O, N or S atom form a 3-8 membered heterocyclic alkyl.

In some embodiments, the molecular weight of the compound disclosed herein is no more than 450 Da. In some embodiments, the molecular weight of the compound disclosed herein is 150-450 Da, 150-300 Da, or 200-300 Da.

The present application also provides a compound having the chemical structure shown in Formula (IA) :

R_a, R_b, R_c, R_d and R_e are independently hydrogen, halogen, C_1-12 alkyl, C_1-12 alkoxy_, cyano, C_1-12 alkylsulfonyl, C_1-6 alkylcarbonyloxyl, C_1-4 alkyloxycarbonyl, mono-, di-or tri-halo-C_1-6 alkyl, C_5-10 aryloxyl or C_5-10 arylcarbonyl； and

at least one of R_a, R_b, R_c, R_d and R_e is not protium.

In some embodiments, R_b, R_c, R_d are all hydrogen, and R_e and R_a are independently hydrogen, halogen, C_1-3 alkyl, C_1-3 alkoxy_, cyano, C_1-3 alkylsulfonyl, C_1-3 alkylcarbonyloxyl, C_1-3 alkyloxycarbonyl, or mono-, di-or tri-halo-C_1-3 alkyl. In some enbodiments, one of R_e and R_a is hydrogen.

The present application also provides a compound having the chemical structure shown in Formula (IB) :

R_g is hydrogen, C_1-6 alkyl, phenyl, or phenylmethyl which is optionally mono-or independently multi-substituted by halogen, hydroxyl, methylthio, C_1-4 alkyl, or C_5-8 aryl； and R_h and R_f are independently hydrogen, C_1-6 alkyl or an amino protecting group； or

R_f and R_g together with C, O, N or S atoms form a 4-8 membered heterocyclic alkyl, and R_h is hydrogen, C_1-6 alkyl or an amino protecting group. In some embodiments, R_g is not isopropyl or benzyl. In some embodiments, when R_f or R_h is an amino protection group, R_g is not isopropyl or benzyl.

The present application also provides a compound having the chemical structure shown in Formula (IC) :

R¹ is C_1-8 alkyl, C_5-8 aryl, or C_5-12 aralkyl which are each optionally mono-or independently multi-substituted by halogen, cyano, hydroxyl, C_1-6 alkyl or C_1-4 alkoxy.

In some embodiments, R¹ is

and wherein R_1a and R_1b are independently hydrogen, C_1-12 alkyl, C_1-4 alkoxy or halogen. In some embodiments, R¹ is

and wherein R_1c is hydrogen, C_1-12 alkyl or halogen.

The present application also provides a compound having the chemical structure shown in Formula (ID) :

R² is- (CH₂) _m-, wherein m ＝ 1-6；

R³ is C_1-12 alkyl, C_5-8 aryl, 3-8 membered heterocyclic alkyl, or 5-8 membered heterocyclic aryl, which are each optionally mono-or independently multi-substituted by halogen, C_1-6 alkyl or C_1-6 alkoxy.

In some embodiment, R² is-CH₂-. In some embodiment, R³ is methyl, ethyl, phenyl, which are each optionally mono-or independently multi-substituted by methoxyl, methyl or ethyl.

The present application also provides a compound having the chemical structure shown in Formula (ID-1) :

R_3a, R_3b, R_3c, R_3d and R_3e are independently hydrogen, halogen, C_1-6 alkyl, or C_1-6 alkoxy.

In some embodiments, the compound is selected from:

Various features of the present invention that are, for brevity, described in the context of a single embodiment, can also be provided separately or in any suitable subcombination.

As used herein, the term “substituted” , when refers to a chemical group, means the chemical group has one or more hydrogen atoms that is/are removed and replaced by substituents. As used herein, the term “substituent” has the ordinary meaning known in the art and refers to a chemical moiety that is covalently attached to, or if appropriate fused to, a parent group. As used herein, the term “optionally substituted” means that the chemical group may have no substituents (i.e. unsubstituted) or may have one or more substituents (i.e. substituted) . It is to be understood that substitution at a given atom is limited by valency.

As used herein, the term “C_n-m” indicates a range of the carbon atoms numbers, wherein n and m are integers and the range of the carbon atoms numbers includes the endpoints (i.e. n and m) and each integer point in between. For examples, C_1-6 indicates a range of one to six carbon atoms, including one carbon atom, two carbon atoms, three carbon atoms, four carbon atoms, five carbon atoms and six carbon atoms.

As used herein, the term “alkyl” , whether as part of another term or used independently, refers to a saturated hydrocarbon group that may be straight-chain or branched-chain. The term “C_n-m alkyl” refers to an alkyl having n to m carbon atoms. In some embodiments, the alkyl group contains 1 to 12, 1 to 8, 1 to 6, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. Examples of alkyl group include, but are not limited to, chemical groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl； higher homologs such as 2-methyl-1-butyl, n-pentyl, 3-pentyl, n-hexyl, 1, 2, 2-trimethylpropyl, and the like.

As used herein, the term “alkenyl” , whether as part of another term or used independently, refers to an unsaturated hydrocarbon group that may be straight-chain or branched-chain having at least one carbon-carbon double bond. The term “C_n-m alkenyl” refers to an alkenyl having n to m carbon atoms. In some embodiments, the alkenyl group contains 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3 carbon atoms. In some embodiments, the alkenyl group contains 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 carbon-carbon double bond. Examples of alkenyl groups include, but are not limited to, chemical groups such as ethenyl, n-propenyl, isopropenyl, n-butenyl, sec-butenyl, and the like.

As used herein, the term “alkynyl” , whether as part of another term or used independently, refers to an unsaturated hydrocarbon group that may be straight-chain or branched-chain having at least one carbon-carbon triple bonds. The term “C_n-m alkynyl” refers to an alkynyl having n to m carbon atoms. In some embodiments, the alkynyl group contains 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3 carbon atoms. In some embodiments, the alkynyl group contains 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 carbon-carbon triple bond. Examples of alkynyl groups include, but are not limited to, chemical groups such as ethynyl, propyn-1-yl, propyn-2-yl, and the like.

As used herein, the term “aryl" or “aromatic” , whether as part of another term or used independently, refers to a mono-or polycyclic carbocyclic ring system radicals with alternating double and single bonds between carbon atoms forming the rings. In some embodiments, the aryl ring systems have 5 to 10, 5 to 8, or 5 to 6 carbon atoms in one or more rings. Examples of aryl groups include, but are not limited to, chemical groups such as phenyl, naphthyl, tetrahydronaphthyl, indanyl, idenyl and the like.

As used herein, the term “aralkyl” , whether as part of another term or used independently, refers to a group of formula -alkyl-aryl. The term “C_n-m aralkyl” refers to aralkyl with a total carbon number between n to m. In some embodiments, the alkyl moiety has 1 to 6, 1 to 4, 1 to 3, or 1 to 2 carbon atoms. In some embodiments, the aralkyl group has 5-12, 5-10, 5-8, or 6-7 carbon atoms. Examples of aralkyl groups include, but are not limited to, various alkyl benzenes and alkyl naphthalenes.

As used herein, the term “aralkenyl” , whether as part of another term or used independently, refers to a group of formula -alkenyl-aryl, wherein the term “C_n-m aralkenyl” refers to an aralkenyl group with a total carbon number between n to m. In some embodiments, the alkenyl moiety contains 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3 carbon atoms. In some embodiments, the aralkenyl group has 6-18, 6-12, 6-10, 6-8, or 6-7 carbon atoms. Examples of aralkenyl groups include, but are not limited to, chemical groups such as styryl, 3- (benzyl) prop-2-enyl, and 6-napthylhex-2-enyl.

As used herein, the term “cycloalkyl” , whether as part of another term or used independently, refers to non-aromatic cyclic hydrocarbons including cyclized alkyl and/or alkenyl groups. Cycloalkyl groups can include mono-or polycyclic (e.g., having 2, 3 or 4 fused rings) groups and spirocycles. In some embodiments, the cycloalkyl is saturated cycloalkyl. Cycloalkyl groups can have 3, 4, 5, 6, 7, 8 ring-forming carbons (C_3-8) . Examples of cycloalkyl groups include, but are not limited to, chemical groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptatrienyl, and the like. In some embodiments, a cycloalkyl used herein may be fused (i.e., having a bond in common with) with one or more aromatic rings, for example, benzo or thienyl derivatives of cyclopentane, cyclohexane, and the like. In some embodiments, a cycloalkyl group containing a fused aromatic ring can be attached through any ring-forming atom including a ring-forming atom of the fused aromatic ring.

As used herein, the term “alkoxy” , whether as part of another term or used independently, refers to a group of formula -O-alkyl. The term “C_n-m alkoxy” means that the alkyl moiety of the alkoxy group has n to m carbon atoms. In some embodiments, the alkyl moiety has 1 to 6, 1 to 4, or 1 to 3 carbon atoms. Examples of alkoxy groups include, but are not limted to, chemical groups such as methoxy, ethoxy, propoxy (e.g., n-propoxy and isopropoxy) , t-butoxy, and the like.

As used herein, the term “aryloxyl” refers to a group of formula -O-aryl, wherein the aryl group is as previously described. “C_n-m aryloxyl” means that the aryl moiety of the aryloxyl group has n to m carbon atoms. In some embodiments, the aryl moiety has 5 to 10, 5 to 8, or 5 to 6 carbon atoms.

As used herein, the term “alkylamino” , whether as part of another term or used independently, refers to a group of formula -NH-alkyl. The term “C_n-m alkylamino” means that the alkyl moiety of the alkylamino group has n to m carbon atoms. In some embodiments, the alkyl moiety has 1 to 6, 1 to 4, or 1 to 3 carbon atoms.

As used herein, the term “arylcarbonyl” , whether as part of another term or used independently, refers to a group of formula -C (＝O) -aryl, wherein the aryl group is as previously described. “C_n-m arylcarbonyl” means that the aryl moiety of the arylcarbonyl group has n to m carbon atoms. In some embodiments, the aryl moiety has 5 to 10, 5 to 8, or 5 to 6 carbon atoms.

As used herein, the term “alkoxycarbonyl” , whether as part of another term or used independently, refers to a group of formula -C (＝O) -O-alkyl. The term “C_n-m alkoxycarbonyl” means that the alkyl moiety of the alkoxycarbonyl group has n to m carbon atoms. In some embodiments, the alkyl moiety has 1 to 6, 1 to 4, 1 to 3 or 1 to 2 carbon atoms.

As used herein, the term “alkylcarbonyloxyl” , whether as part of another term or used independently, refers to a group of formula -O-C (＝O) -alkyl. The term “C_n-m alkylcarbonyloxyl” means that the alkyl moiety of the alkylcarbonyloxyl group has n to m carbon atoms. In some embodiments, the alkyl moiety has 1 to 6, 1 to 4, 1 to 3 or 1 to 2 carbon atoms.

As used herein, the term “n membered” , wherein n is an integer typically employed in combination with a ring system to describe the number of ring-forming atoms in the ring system. For example, piperidinyl is an example of a 6 membered heterocycloalkyl ring, pyrazolyl is an example of a 5 membered heteroaryl ring, pyridyl is an example of a 6 membered heteroaryl ring, and 1, 2, 3, 4-tetrahydro-naphthalene is an example of a 10 membered cycloalkyl group.

As used herein, the term “heterocyclic aryl” refers to aryl group wherein at least one ring atom in the aromatic ring is a heteroatom, and the remainder of the ring atoms being carbon atoms. The term “n-m membered heterocyclic aryl” refers to heterocyclic aryl having n to m ring-forming members. Example heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, phosphorus, and the like. In some embodiments, heterocyclic aryl can have 5 to 10, 5 to 8, or 5 to 6 ring-forming members. In some embodiments, heterocyclic aryl is 5 membered or 6 membered heterocyclic aryl. Examples of heterocyclic aryl include, but are not limited to, furanyl, thienyl, pyridyl, pyrrolyl, N-lower alkyl pyrrolyl, pyridyl-N-oxide, pyrimidyl, pyrazinyl, imidazolyl, indolyl and the like.

A 5 membered heterocyclic aryl is a heterocyclic aryl with a ring having five ring atoms, wherein one or more (e.g., 1, 2, or 3) ring atoms can be independently selected from N, O, P, and S. Exemplary 5 membered heterocyclic aryl are thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, pyrazolyl, isothiazolyl, isoxazolyl, 1, 2, 3-triazolyl, tetrazolyl, 1, 2, 3-thiadiazolyl, 1, 2, 3-oxadiazolyl, 1, 2, 4-triazolyl, 1, 2, 4-thiadiazolyl, 1, 2, 4-oxadiazolyl, 1, 3, 4-triazolyl, 1, 3, 4-thiadiazolyl and 1, 3, 4-oxadiazolyl.

A 6 membered heterocyclic aryl is a heterocyclic aryl with a ring having six ring atoms, wherein one or more (e.g., 1, 2, or 3) ring atoms can be independently selected from N, O, P, and S. Exemplary 6 membered heterocyclic aryl are pyridyl, pyrazinyl, pyrimidinyl, triazinyl and pyridazinyl.

As used herein, the term “heterocyclic alkyl” refers to cycloalkyl group wherein at least one ring atom in the ring systems is a heteroatom, and the remainder of the ring atoms being carbon atoms. The term “n-m membered heterocyclic alkyl” refers to heterocyclic alkyl having n to m ring-forming members. In addition, the ring may also have one or more double bonds, but not have a completely conjugated system. In some embodiments, the heterocyclic alkyl is saturated heterocyclic alkyl. Examples of heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, phosphorus, and the like. In some embodiments, heterocyclic alkyl has 3 to 8, 3 to 6, or 4 to 6 ring-forming carbons. Examples of heterocyclic alkyl include, but are not limited to, azetidine, aziridine, pyrrolidyl, piperidyl, piperazinyl, morpholinyl, thiomorpholinyl, homopiperazinyl, and the like.

As used herein the terms “halo” and “halogen” refer to an atom selected from fluorine, chlorine, bromine and iodine.

As used herein, “mono-, di-or tri-halo-C_n-m alkyl” refers to an alkyl group that is substituted by one, two or three halo, wherein the alkyl group has n to m carbon atoms and the halo as substituent may be same or different. Examples of mono-, di-or tri-halo-C_n-m alkyl include without limitation, trichloromethyl, chloromethyl, bischloromethyl, chlorobromomethyl.

As used herein the terms “cyano” refer to a group of formula -CN.

As used herein, the term “hydroxyl” refers to a group of formula -OH.

As used herein, the term “methylthio” refers to a group of formula -S-CH₃.

As used herein, the term “alkylsulfonyl” refers to a group of formula -sulfonyl-alkyl. The term “C_n-m alkylsulfonyl” refers to alkylsulfonyl wherein the alkyl moiety has n to m carbon atoms. In some embodiments, the alkyl group has 1 to 6, 1 to 4, or 1 to 3 carbon atoms. Examples of alkylsulfonyl groups include without limitation, methanesulfonyl, ethanesulfonyl, tert-butanesulfonyl, and the like.

As used herein, the term “amino” refers to a group of formula -NH₂.

As used herein, the term “substituted amino” refers to an amino that is mono-or independently substituted by one or more substituents. Examples of substituents include, but are not limited to, halogen, hydroxyl, C_1-4 alkyl, C_5-8 aryl, C_1-6 alkoxyl, C_3-8 cycloalkyl, 3-8 membered heterocyclic alkyl, or 3-8 membered heterocyclic aryl, C_1-4 alkylsulfonyl, C_5-10 aryloxyl, C_5-10 arylcarbonyl or C_1-6 alkyloxycarbonyl, amino protecting group, and the like.

As used herein, the term “amino protecting group” refers to a substituent that protects an amino functionality against undesirable reactions during synthetic procedures. Examples of amino protecting groups include, but are not limited to, carbamate-protecting groups, such as 2-trimethyl-silylethoxycarbonyl (Teoc) , 1-methyl-1- (4-bi-phenyl-yl) -ethoxy-carbonyl (Bpoc) , t-butoxycarbonyl (Boc) , allyloxycarbonyl (Alloc) , 9-fluorenyl-methyloxycarbonyl (Fmoc) , and benzyl-oxycarbonyl (Cbz) ； amide-protecting groups, such as formyl, acetyl, trihaloacetyl, benzoyl, and nitrophenylacetyl； sulfona-mide-protecting groups, such as 2-nitrobenzenesulfonyl； and imine-and cyclic imide-protecting groups, such as phthalimido and dithiasuccinoyl.

As used herein, the term “compound” is meant to include all stereoisomers (eg. enantiomers and diastereomers) , geometric iosomers, tautomers, and isotopes of the structures depicted. Compounds herein identified by name or structure as one particular tautomeric form are intended to include other tautomeric forms unless otherwise specified.

The compounds described herein can be asymmetric (e.g., having one or more stereocenters) . All stereoisomers, such as enantiomers and diastereomers, are intended unless otherwise indicated. Compounds of the present invention that contain asymmetrically substituted carbon atoms can be isolated in optically active or racemic forms. Methods on how to prepare optically active forms from optically inactive starting materials are known in the art, such as by resolution of racemic mixtures or by stereoselective synthesis. Many geometric isomers of olefins, carbon-carbon double bonds, and the like can also be present in the compounds described herein, and all such stable isomers are contemplated in the present invention. Cis and trans geometric isomers of the compounds of the present application are described and may be isolated as a mixture of isomers or as separated isomeric forms.

In some embodiments, the compounds described herein have the (R) -configuration. In some embodiments, the compounds described herein have the (S) -configuration.

Resolution of racemic mixtures of compounds can be carried out by any of numerous methods known in the art. An example method includes fractional recrystallizaion using a chiral resolving acid, which is an optically active, salt-forming organic acid. Suitable resolving agents for fractional recrystallization methods are, for example, optically active acids, such as the D and L forms of tartaric acid, diacetyltartaric acid, dibenzoyltartaric acid, mandelic acid, malic acid, lactic acid or the various optically active camphorsulfonic acids such as β-camphorsulfonic acid. Other resolving agents suitable for fractional crystallization methods include stereoisomerically pure forms of α-methylbenzylamine (e.g., S and R forms, or diastereomerically pure forms) , 2-phenylglycinol, norephedrine, ephedrine, N-methylephedrine, cyclohexylethylamine, 1, 2-diaminocyclohexane, and the like.

Resolution of racemic mixtures can also be carried out by elution on a column packed with an optically active resolving agent (e.g., dinitrobenzoylphenylglycine) . Suitable elution solvent composition can be determined by one skilled in the art.

Compounds of the invention also include tautomeric forms. Tautomeric forms result from the swapping of a single bond with an adjacent double bond together with the concomitant migration of a proton. Tautomeric forms include prototropic tautomers which are isomeric protonation states having the same empirical formula and total charge. Example prototropic tautomers include ketone-enol pairs, amide-imidic acid pairs, lactam-lactim pairs, enamine-imine pairs, and annular forms where a proton can occupy two or more positions of a heterocyclic system, for example, 1H-and 3H-imidazole, 1H-, 2H-and 4H-1, 2, 4-triazole, 1H-and 2H-isoindole, and 1H-and 2H-pyrazole. Tautomeric forms can be in equilibrium or sterically locked into one form by appropriate substitution.

Compounds of the invention can also include all isotopes of atoms occurring in the intermediates or final compounds. Isotopes include those atoms having the same atomic number but different mass numbers. For example, isotopes of hydrogen include protium, deuterium and tritium. In some embodiments, the isotope of hydrogen is protium and deuterium. In some embodiments, the hydrogens on the aromatic ring of the compounds include at least one deuterium. In some embodiments, the hydrogens on the aromatic ring of the compounds are all deuteriums.

In some embodiments, the compound of the invention can convert to gamma-hydroxybutyric acid after oral administration. In some embodiments, the compound of the invention can enter into human circulatory system through a biological process after oral administration.

In some embodiments, the compound of the invention have higher oral bioavailability than the oral bioavailablity of GHB sodium salt. In some embodiments, the oral bioavailability of the compound of the invention is 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5. 3, 4, 5, 6, 8, or 10 times higher than the oral bioavailability of GHB sodium salt. In some embodiments, the compound of the invention have higher colonic absorption than the colonic absorption of GHB. In some embodiments, the colonic absorption of the compound of the invention is 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5. 3, 4, 5, 6, 8, or 10 times higher than the colonic absorption of GHB.

Synthesis Method

Compounds of the invention, including salts, esters, hydrates, or solvates thereof, can be prepared using any known organic synthesis techniques and can be synthesized according to any of numerous possible synthetic routes.

The reactions for preparing compounds of the invention can be carried out in suitable solvents, which can be readily selected by one skilled in the art of organic synthesis. Suitable solvents can be substantially non-reactive with the starting materials (reactants) , the intermediates, or products at the temperatures at which the reactions are carried out, e.g., temperatures that can range from the solvent's freezing temperature to the solvent's boiling temperature. A given reaction can be carried out in one solvent or a mixture of more than one solvent. Depending on the particular reaction step, suitable solvents for a particular reaction step can be selected by a skilled artisan.

Preparation of compounds of the invention can involve the protection and deprotection of various chemical groups. The need for protection and deprotection, and the selection of appropriate protecting groups, can be readily determined by one skilled in the art. The chemistry of protecting groups can be found, for example, in T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3rd Ed., Wiley &Sons, Inc., New York (1999) , which is incorporated herein by reference in its entirety.

Reactions can be monitored according to any suitable method known in the art. For example, product formation can be monitored by spectroscopic means, such as nuclear magnetic resonance spectroscopy (e.g., ¹H or ¹³C) , infrared spectroscopy, spectrophotometry (e.g., UV-visible) , mass spectrometry, or by chromatographic methods such as high performance liquid chromatography (HPLC) , liquid chromatography-mass spectroscopy (LCMS) , or thin layer chromatography (TLC) . Compounds can be purified by those skilled in the art by a variety of methods, including high performance liquid chromatography (HPLC) ( “Preparative LC-MS Purification: Improved Compound Specific Method Optimization” Karl F. Blom, Brian Glass, Richard Sparks, Andrew P. Combs J. Combi. Chem. 2004, 6 (6) , 874-883, which is incorporated herein by reference in its entirety) and normal phase silica chromatography.

For example, compounds of Formula I can be formed as shown in Scheme 1.

Scheme 1

Alternatively, compounds of Formula I can be formed as shown in Scheme 2.

Scheme 2

For example, one representative compound of Formula IC can be formed as shown in Scheme 3.

Scheme 3

For example, compounds of Formula ID can be formed as shown in Scheme 4.

Scheme 4

Pharmaceutical Composition

The present application provides pharmaceutical composition comprising one or more compounds of the invention, and a pharmaceutically acceptable carrier.

These pharmaceutical compositions can be prepared in a manner well known in the pharmaceutical art. In some embodiments, the compounds of the invention may be admixed with pharmaceutically acceptable carrier for the preparation of pharmaceutical composition.

As used herein, the phrase “pharmaceutically acceptable” refers to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. In some embodiments, compounds, materials, compositions, and/or dosage forms that are pharmaceutically acceptable refer to those approved by a regulatory agency (such as U.S. Food and Drug Administration, China Food and Drug Administration or European Medicines Agency) or listed in generally recognized pharmacopoeia (such as U.S. Pharmacopoeia, China Pharmacopoeia or European Pharmacopoeia) for use in animals, and more particularly in humans.

As used herein, the term “pharmaceutically acceptable carrier” refers to any and all solvents, excipients, coatings, antibacterial and antifungal agents, flavoring agents, isotonic and absorption delaying agents, and the like that are pharmaceutically acceptable and can facilitate storage and administration of the compounds of the present application to a subject. Pharmaceutically acceptable carrier that can be employed in present invention includes those generally known in the art, such as those described in “Remington Pharmaceutical Sciences” Mack Pub. Co., New Jersey (1991) , which is incorporated herein by reference.

Examples of pharmaceutically acceptable carriers include, but are not limited to, solvents, liposomes, polymeric excipients and the like.

In certain embodiments, the pharmaceutically acceptable carrier is a solvent that can dissolve or disperse the compounds of the present application. Illustrative examples of solvent include, without limitation, buffer saline, normal saline, phosphate buffer, citrate buffer, acetate buffer, bicarbonate buffer, sucrose solution, polysorbate solution, oil, ester, and alchohol.

In certain embodiments, the pharmaceutically acceptable carriers are liposomes, and the compounds of the present invention can be encapsulated within the aqueous portion or lipid portion of the liposomes. Illustrative examples of liposomes include, without limitation, liposomes based on 3 [N- (N', N'-dimethylaminoethane) carbamoyl] cholesterol (DC-Chlo) , liposomes based on N- (2, 3-dioleoyloxy) propyl-N, N, N- trimethylammonium chloride (DOTMA) , and liposomes based on 1, 2-dioleoyloxy-3-trimethylammonium propane (DOTAP) .

In certain embodiments, the pharmaceutically acceptable carriers are polymeric excipients such as, without limitation, microspheres, microcapsules, polymeric micelles and dendrimers. The compounds of the present application may be encapsulated, adhered to, or coated on the polymer-based components by methods known in the art.

The form of pharmaceutical compositions depends on a number of criteria, including, but not limited to, route of administration, extent of disease, or dose to be administered. The pharmaceutical compositions can be formulated for oral, nasal, rectal, percutaneous, intravenous, or intramuscular administration. In accordance to the desired route of administration, the pharmaceutical compositions can be formulated in the form of tablets, pills, powders, lozenges, sachets, cachets, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium) or ointments.

For oral administration, powders, granules, pills, tablets, caplets, capsules, and gelcaps are acceptable as solid dosage forms. These can be prepared, for example, by mixing one or more compounds of the present application with at least one carrier such as sucrose, lactose, cellulose sugar, mannitol, maltitol, dextran, sorbitol, starch, agar, alginates, chitins, chitosans, pectins, tragacanth gum, gum arabic, gelatins, collagens, casein, albumin, synthetic or semi-synthetic polymers or glycerides, methyl cellulose, hydroxypropylmethyl-cellulose, and/or polyvinylpyrrolidone. In some embodiments, solid dosage forms for oral administration can further comprise other carrier ingredients to aid in manufacture or administration with lubricants such as magnesium stearate, or preservatives such as paraben or sorbic acid, or anti-oxidants such as ascorbic acid, tocopherol or cysteine, a disintegrating agents, or chelating agents such as EDTA, binders, thickeners, flavoring agents or perfuming agents. In certain embodiments, solid dosage forms for oral administration may additionally comprise dyestuffs or pigments for identification. Tablets and pills may be further treated with suitable coating materials known in the art, such as moisture protective, enteric, or sustained release coatings.

For oral administration, emulsions, syrups, elixirs, suspensions, slurries and solutions are acceptable as liquid dosage forms. These can be prepared, for example, by mixing one or more compounds of the present invention with sterile inactive solvent, such as but not limited to, water, alcohol, oil and a combination thereof. In some embodiments, the inactive diluent used in the liquid dosage form for oral administration comprise oil, such as but not limited to, peanut oil, sesame oil, cottonseed oil, corn oil and olive oil. In some embodiments, the inactive diluent used in the liquid dosage form for oral administration comprise esters of fatty acids, such as but not limited to, ethyl oleate, isopropyl myristate, fatty acid glycerides and acetylated fatty acid glycerides. In some embodiments, the inactive diluent used in the liquid dosage form for oral administration comprise alcohols, such as but not limited to, ethanol, isopropyl alcohol, hexadecyl alcohol, glycerol and propylene glycol. In some embodiment, liquid dosage forms for oral administration can further comprise surfactants, suspending agents, emulsifying agents, stabilizers, flavoring agents, chelating agents, preservatives, antioxidants, solubilizers (such as propylene glycol, glycerin, or sorbitol) , dyes, or thickeners. In some embodiments, the liquid dosage form for oral administration can further comprise pH adjusting agent, such as but not limited to, sodium hydroxide, hydrochloric acid, or malic acid.

The pharmaceutical composition of the invention can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art. In some embodiments, the composition is formulated in a sustained released form. As used herein, the term “sustained released form” refers to release of the active agent from the pharmaceutical composition so that it becomes available for bio-absorption in the subject, primarily in the gastrointestinal tract of the subject, over a prolonged period of time (extended release) , or at a certain location (controlled release) . In some embodiments, the prolonged period of time can be about 1 hour to 24 hours, 2 hours to 12 hours, 3 hours to 8 hours, 4 hours to 6 hours, 1 to 2 days or more. In certain embodiments, the prolonged period of time is at least about 4 hours, at least about 8 hours, at least about 12 hours, or at least about 24 hours.

In some embodiments, the sustained release form of pharmaceutical compositions are tablets or pills, and the tablets or pills are coated or otherwise formulated to provide a dosage form affording the advantage of prolonged action. Factors affecting drug release are well known to the skilled artisan and have been described in the art (Bamba et al., Int. J. Pharm., 1979, 2, 307) , which is incorporated herein by reference in its entirety. For example, release rate of the active agent can not only be controlled by dissolution of the active agent in gastrointestinal fluid and subsequent diffusion out of the tablet or pills independent of pH, but can also be influenced by physical processes of disintegration and erosion of the tablet. In some embodiments, polymeric materials as described in “Medical Applications of Controlled Release, ” Langer and Wise (eds. ) , CRC Pres., Boca Raton, Florida (1974) ； “Controlled Drug Bioavailability, ” Drug Product Design and Performance, Smolen and Ball (eds. ) , Wiley, New York (1984) ； Ranger and Peppas, 1983, J Macromol. Sci. Rev. Macromol Chem. 23: 61； see also Levy et al., 1985, Science 228: 190； During et al., 1989, Ann. Neurol. 25: 351； Howard et al., 1989, J. Neurosurg. 71: 105 can be used for sustainted release. The above references are incorporated herein by reference in its entirety.

In some embodiments, polymeric materials are used for oral sustained release delivery. Examples of the polymeric materials include sodium carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose and hydroxyethylcellulose. Other cellulose ethers have been described in Alderman, Int. J. Pharm. Tech. &Prod. Mfr., 1984, 5 (3) 1-9, which is incorporated herein by reference in its entirety. In some embodiments, enteric-coated preparations can be used for oral sustained release administration. Examples of the coating materials include polymers with a pH-dependent solubility (i.e., pH-controlled release) , polymers with a slow pH-dependent rate of swelling, dissolution or erosion (i.e., time-controlled release) , polymers that are degraded by enzymes (i.e., enzyme-controlled release) and polymers that form firm layers that are destroyed by an increase in pressure (i.e., pressure-controlled release) . In some embodiments, osmotic delivery systems are used for oral sustained release administration as described in Verma et al., Drug Dev. Ind. Pharm., 2000, 26: 695-708, which is incorporated herein by reference in its entirety. In a preferred ambodiment, OROS^TM osmotic devices are used for oral sustained release delivery devices as described in Theeuwes et al., United States Patent No. 3, 845, 770； Theeuwes et al., United States Patent No. 3, 916, 899 , which are incorporated herein by reference in its entirety. In some embodiments, a controlled-release system can be placed in proximity of the target of the compounds and/or composition of the invention, thus requiring only a fraction of the systemic dose, see, e.g., Goodson, in “Medical Applications of Controlled Release, ” supra, vol. 2, pp. 115-138 (1984) , which is incorporated herein by reference in its entirety. Other controlled-release systems as described in Langer, 1990, Science 249: 1527-1533 may also be used, which is incorporated herein by reference in its entirety.

The compositions can be formulated in a unit dosage form, each dosage containing from about 0.5 to about 30 g, about 1 to about 20 g, about 2 to about 20 g, about 3 to about 20 g, about 4 to about 20 g, about 5 to about 20 g, about 6 to about 20 g, about 7 to about 20 g, about 8 to about 20 g, about 9 to about 20 g, about 10 to about 20 g, about 11 to about 20 g, about 12 to about 20 g, about 13 to about 20 g, about 14 to about 20 g, about 15 to about 20 g, about 16 to about 20 g, about 17 to about 20 g, about 18 to about 20 g, 2 to about 18 g, about 2 to about 16 g, about 2 to about 14 g, about 2 to about 12 g, about 2 to about 10 g, about 2 to about 9 g, about 2 to about 8 g, about 2 to about 6 g of the active ingredient. The term “unit dosage forms” refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical carrier.

Method for Treatment

The present application provides, a method of treating a disease, comprising administering to a subject an effective amount of one or more compounds of the invention.

In some embodiments, the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease. In some embodiments, the disease is excessive daytime sleepiness or cataplexy associated with narcolepsy.

Administration may be via oral, nasal, intravenous, subcutaneous, sublingual, or intramuscular administration.

The frequency of administration of the compound will vary depending upon what is being administered, the amount of the therapeutic agent, the purpose of the administration, the state of the patient, the manner of administration, and the like. Determination of frequency of administration is well within the capability of those skilled in the art. In some embodiments, the administration is conducted no more than two time per day, no more than one time per day, no more than two times per three days, no more than one time per two days, no more than one time per three days, no more than one time per five days, no more than one time per one week, or no more than one time per two weeks.

As used herein, the term “effective amount” means an amount of the therapeutic agent that is effective to provide a desired outcome. Determination of a therapeutically effective amount is well within the capability of those skilled in the art. Generally, a therapeutically effective amount can vary with the subject’s history, age, condition, sex, as well as the severity and type of the medical condition in the subject, and administration of other agents that inhibit pathological processes in neurodegenerative disorders. In some embodiments, the effective amount of the therapeutic agent is from about 0.5 to about 30 g, about 1 to about 15 g, about 2 to about 15 g, about 3 to about 10 g, about 4 to about 10 g.

As used herein, the term "treating" or "treatment" of any disease or disorder refers to delaying onset of the disease or disorder； ameliorating at least one of the clinical symptoms relating to the disease or disorder； or both.

Pharmaceutical Use

The present invention also provides use of one or more compounds of the invention in the manufacture of a medicament for treating a disease. In some embodiments, the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease. In some embodiments, the disease is excessive daytime sleepiness or cataplexy associated with narcolepsy.

The present invention also provides the compounds of the invention for treating a disease. In some embodiments, the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease. In some embodiments, the disease is excessive daytime sleepiness or cataplexy associated with narcolepsy.

EXAMPLES

The following examples are presented to illustrate the present invention. They are not intended to be limiting in any manner.

EXAMPLE 1: Preparation and characterization of exemplary compounds

Compounds encompassed in the present invention can be prepared via several different schemes. Detailed preparation processes of 63 exemplary compounds via various schemes are described below and the characterization results are listed for each compound as well.

Unless stated otherwise, all reagents were purchased from commercial suppliers without further purification. Solvent drying by standard methods was employed when necessary. The plates used for thin-layer chromatography (TLC) were E. Merck silica gel 60F254 (0.24 nm thickness) precoated on aluminum plates, and then visualized under UV light (365 nm and 254 nm) or through staining with a 5％of dodecamolybdophosphoric acid in ethanol and subsequent heating. Column chromatography was performed using silica gel (200-400 mesh) from commercial suppliers. ¹H NMR spectra were recorded on an Agilent 400-MR NMR spectrometer (400.00 MHz for 1H) at room temperature. Solvent signal was used as reference for ¹H NMR (CDCl₃, 7.26 ppm； CD₃OD, 3.31 ppm) . The following abbreviations were used to explain the multiplicities: s ＝ singlet, d ＝ doublet, t ＝ triplet, q ＝ quartet, br. s. ＝ broad singlet, dd ＝ double doublet, td ＝ triple doublet, dt ＝ double triplet, dq ＝ double quartet, m ＝ multiplet. Other abbreviations used in the experimental details are as follows: Ar ＝ aryl, Boc ＝ tert-butyloxy carbonyl, δ ＝ chemical shift in parts per million downfield from tetramethylsilane, DCM ＝ dichloromethane, DIPEA ＝ diisopropylethylamine, DMAP ＝ 4- (dimethylamino) pyridine, EA ＝ ethyl acetate, Et ＝ ethyl, Hex. ＝ hexanes, Hz ＝ hertz, J ＝ coupling constant (in NMR) , Me ＝ methyl, min ＝ minute (s) , NMR ＝ nuclear magnetic resonance, Ph ＝ phenyl, ppm ＝ parts per million, iPr ＝ isopropyl, tert- ＝ tertiary, THF ＝ tetrahydrofuran, TLC ＝ thin-layer chromatography.

Scheme 1

Example 1-1

Intermediate Compound 1’ : 4-hydroxybutyl 2-methylbenzoate

A solution of 2-methylbenzoyl chloride (770 mg, 5 mmol) in dichloromethane (DCM) (2 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol ) and Et₃N (505 mg, 5 mmol) in DCM (8 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with 5 mL DCM. The combined organic phase was then washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (470 mg, 45％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.91 (d, J ＝ 8.0 Hz , 1 H) , 7.40 (t, J ＝ 7.4 Hz, 1 H) , 7.26-7.22 (m, 2 H) , 4.34 (t, J ＝ 6.8 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 2.60 (s, 3 H) , 1.90-1.83 (m, 2 H) , 1.77-1.70 (m, 2 H) .

Compound 1: 4- (2-methylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-methylbenzoate (400 mg, 1.92 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , then dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (380 mg, 89％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.91 (d, J ＝ 8.0 Hz, 1 H) , 7.40 (t, J ＝ 7.8 Hz, 1 H) , 7.28-7.22 (m, 2 H) , 4.36 (t, J ＝ 6.2 Hz, 2 H) , 2.61 (s, 3 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.15-2.08 (m, 2 H) .

Example 1-2

Intermediate Compound 2’ : 4-hydroxybutyl 3-methylbenzoate

A solution of 3-methylbenzoyl chloride (616 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1， 4-diol (450 mg， 5 mmol ) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with 5 mL H₂O and stirred for 5 min. The aqueous phase was separated and extracted with 5 mL DCM. The combined organic phase was then washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (410 mg, 49％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.83-7.81 (m, 2 H) , 7.35-7.28 (m, 2 H) , 4.33 (t, J ＝ 6.6 Hz, 2 H) , 3.70 (t, J ＝ 6.4 Hz, 2 H) , 2.38 (s, 3 H) , 2.07 (s, 1 H) , 1.89-1.82 (m, 2 H) , 1.75-1.68 (m, 2 H) .

Compound 2: 4- (3-methylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-methylbenzoate (350 mg, 1.68 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (333 mg, 89％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.83-7.81 (m, 2 H) , 7.36-7.28 (m, 2 H) , 4.36 (t, J ＝ 6.2 Hz, 2 H) , 2.53 (t, J ＝ 7.2 Hz, 2 H) , 2.38 (s, 3 H) , 2.14-2.07 (m, 2 H) .

Example 1-3

Intermediate Compound 3’ : 4-hydroxybutyl 4-methylbenzoate

A solution of 4-methylbenzoyl chloride (616 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol ) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (470 mg, 56％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.91 (d, J ＝ 8.4 Hz, 2 H) , 7.20 (d, J ＝ 8.4 Hz, 2 H) , 4.32 (t, J ＝ 6.6 Hz, 2 H) , 3.69 (t, J ＝ 6.6 Hz, 2 H) , 2.38 (s, 3 H) , 2.19 (br. s., 1 H) , 1.87-1.80 (m, 2 H) , 1.74-1.67 (m, 2 H) .

Compound 3: 4- (4-methylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-methylbenzoate (400 mg, 1.92 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (364 mg, 85％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.91 (d, J ＝ 8.0 Hz, 2 H) , 7.23 (d, J ＝ 8.0 Hz, 2 H) , 4.36 (t, J ＝ 6.2 Hz, 2 H) , 2.54 (t, J ＝ 7.4 Hz, 2 H) , 2.40 (s, 3 H) , 2.14-2.08 (m, 2 H) .

Example 1-4

Intermediate Compound 4’ : 4-hydroxybutyl 4-fluorobenzoate

A solution of 4-fluorobenzoyl chloride (632 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (540 mg, 64％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.07-8.04 (m, 2 H) , 7.11 (t, J ＝ 8.6 Hz, 2 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 1.90-1.83 (m, 2 H) , 1.76-1.69 (m, 2 H) , 1.41 (br. s., 1 H) .

Compound 4: 4- (4-fluorobenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-fluorobenzoate (500 mg, 2.36 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (356 mg, 67％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.06-8.03 (m, 2 H) , 7.11 (t, J ＝ 8.6 Hz, 2 H) , 4.38 (t, J ＝ 6.4 Hz, 2 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.15-2.07 (m, 2 H) .

Example 1-5

Intermediate Compound 5’ : 4-hydroxybutyl 2, 4, 6-trimethylbenzoate

A solution of 2, 4, 6-trimethylbenzoyl chloride (728 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃ was added a solution of 2, 4, 6-trimethylbenzoyl chloride (728 mg, 4 mmol) in DCM (5 mL) dropwise during 10 min. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (600 mg, 64％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 6.85 (s, 2 H) , 4.34 (t, J ＝ 6.6 Hz, 2 H) , 3.69 (t, J ＝ 6.6 Hz, 2 H) , 2.29 (s, 6 H) , 2.28 (s, 3 H) , 1.88-1.80 (m, 2 H) , 1.73-1.66 (m, 2 H) , 1.49 (br. s., 1 H) .

Compound 5: 4- (2, 4, 6-trimethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2, 4, 6-trimethylbenzoate (500 mg, 2.12 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1-3: 1 to yield the titled compound (450 mg, 85％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 6.85 (s, 2 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 2.51 (t, J ＝ 7.2 Hz, 2 H) , 2.29 (s, 6 H) , 2.28 (s, 3 H) , 2.12-2.05 (m, 2 H) .

Example 1-6

Intermediate Compound 6’ : 4-hydroxybutyl 2-methoxybenzoate

A solution of 2-methoxybenzoyl chloride (680 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (370 mg, 41％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.79 (dd, J ＝ 1.6, 7.6 Hz, 1 H) , 7.49-7.45 (m, 1 H) , 7.00-6.97 (m, 2 H) , 4.35 (t, J ＝ 6.2 Hz, 2 H) , 3.90 (s, 3 H) , 3.77-3.68 (m, 2 H) , 1.91-1.83 (m, 2 H) , 1.77-1.69 (m, 2 H) , 1.56 (br. s., 1 H) .

Compound 6: 4- (2-methoxybenzoyloxy) butanoic acid

Jones reagent was added in portions toa stirred mixture of 4-hydroxybutyl 2-methoxybenzoate (300 mg, 1.34 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (244 mg, 76％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.78 (dd, J ＝ 1.8, 7.8 Hz, 1 H) , 7.49-7.45 (m, 1 H) , 7.00-6.96 (m, 2 H) , 4.36 (t, J ＝ 6.0 Hz, 2 H) , 3.90 (s, 3 H) , 2.57 (t, J ＝ 7.4 Hz, 2 H) , 2.13-2.07 (m, 2 H) .

Example 1-7

Intermediate Compound 7’ : 4-hydroxybutyl 3-methoxybenzoate

A solution of 3-methoxybenzoyl chloride (680 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (420 mg, 47％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.63 (d, J ＝ 7.6 Hz, 1 H) , 7.56 (s, 1 H) , 7.34 (t, J ＝ 8.0 Hz, 1 H) , 7.10 (dd, J ＝ 2.4, 8.0 Hz, 1 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.85 (s, 3 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 1.91-1.84 (m, 2 H) , 1.76-1.69 (m, 2 H) .

Compound 7: 4- (3-methoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-methoxybenzoate (350 mg, 1.56 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1-3: 1 to yield the titled compound (287 mg, 77％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.63 (d, J ＝ 8.0 Hz, 1 H) , 7.55 (s, 1 H) , 7.35 (t, J ＝ 7.8 Hz, 1 H) , 7.10 (dd, J ＝ 2.4, 8.0 Hz, 1 H) , 4.39 (t, J ＝ 6.4 Hz, 2 H) , 3.86 (s, 3 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.16-2.08 (m, 2 H) .

Example 1-8

Intermediate Compound 8’ : 4-hydroxybutyl 4-methoxybenzoate

A solution of 4-methoxybenzoyl chloride (680 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash columnwith Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (500 mg, 56％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.99 (d, J ＝ 9.2 Hz, 2 H) , 6.91 (d, J ＝ 8.8 Hz, 2 H) , 4.33 (t, J ＝ 6.6 Hz, 2 H) , 3.86 (s, 3 H) , 3.73 (s, 2 H) , 1.89-1.82 (m, 2 H) , 1.76-1.69 (m, 2 H) , 1.44 (br. s., 1 H) .

Compound 8: 4- (4-methoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-methoxybenzoate (400 mg, 1.79 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (370 mg, 87％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.99 (d, J ＝ 9.2 Hz, 2 H) , 6.92 (d, J ＝ 8.8 Hz, 2 H) , 4.35 (t, J ＝ 6.2 Hz, 2 H) , 3.86 (s, 3 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.13-2.08 (m, 2 H) .

Example 1-9

Intermediate Compound 9’ : 4-hydroxybutyl 2-chlorobenzoate

A solution of 2-chlorobenzoyl chloride (2 g, 11.43 mmol) in DCM (10 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (3085 mg, 34.28 mmol) and Et₃N (2308 mg, 22.85 mmol) in DCM (50 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0～25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (30 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with brine (20 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1 to yield the titled compound (1.8 g, 69％) as colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.81 (dd, J ＝ 1.4, 7.8 Hz, 1 H) , 7.45-7.38 (m, 2 H) , 7.34-7.28 (m, 1 H) , 4.38 (t, J ＝ 6.4 Hz, 2 H) , 3.71 (t, J ＝ 6.4 Hz, 2 H) , 1.91-1.84 (m, 2 H) , 1.77-1.70 (m, 2 H) .

Compound 9: 4- (2-chlorobenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-chlorobenzoate (1.6 g, 7.02 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (20 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (3 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (1 g, 59％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.82 (dd, J ＝ 1.2, 8.0 Hz, 1 H) , 7.49-7.38 (m, 2 H) , 7.34-7.29 (m, 1 H) , 4.41 (t, J ＝ 6.2 Hz, 2 H) , 2.57 (t, J ＝ 7.2 Hz, 2 H) , 2.16-2.09 (m, 2 H) .

Example 1-10

Intermediate Compound 10’ : 4-hydroxybutyl 3-chlorobenzoate

A solution of 3-chlorobenzoyl chloride (696 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (550 mg, 60％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.00 (s, 1 H) , 7.92 (d, J ＝ 7.6 Hz, 1 H) , 7.52 (dd, J ＝ 0.8, 8.4 Hz, 1 H) , 7.38 (t, J ＝ 7.8 Hz, 1 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (dd, J ＝ 6.2, 10.6 Hz, 2 H) , 1.91-1.84 (m, 2 H) , 1.76-1.69 (m, 3 H) .

Compound 10: 4- (3-chlorobenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-chlorobenzoate (500 mg, 2.19 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (420 mg, 79％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.00 (s, 1 H) , 7.92 (d, J ＝ 7.6 Hz, 1 H) , 7.55-7.52 (m, 1 H) , 7.39 (t, J ＝ 7.8 Hz, 1 H) , 4.39 (t, J ＝ 6.2 Hz, 2 H) , 2.55 (t, J ＝ 7.2 Hz, 2 H) , 2.16-2.09 (m, 2 H) .

Example 1-11

Intemediate Compound 11’ : 4-hydroxybutyl 4-chlorobenzoate

A solution of 4-chlorobenzoyl chloride (2 g, 11.43 mmol) in DCM (10 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (3085 mg, 34.28 mmol) and Et₃N (2308 mg, 22.85 mmol) in DCM (50 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 1 h. After that, the reaction mixture was diluted with H₂O (30 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with brine (20 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (1.6 g, 62％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (d, J ＝ 8.4 Hz, 2 H) , 7.41 (d, J ＝ 8.4 Hz, 2 H) , 4.36 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 1.90-1.84 (m, 2 H) , 1.75-1.69 (m, 2 H) .

Compound 11: 4- (4-chlorobenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-chlorobenzoate (1.5 g, 6.58 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ over 16 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (20 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (3 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to afford the title compound (600 mg, 38％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.96 (d, J ＝ 8.0 Hz, 2 H) , 7.41 (d, J ＝ 8.0 Hz, 2 H) , 4.39 (t, J ＝ 6.2 Hz, 2 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.15-2.07 (m, 2 H) .

Example 1-12

Intermediate Compound 12’ : 4-hydroxybutyl 3-cyanobenzoate

A solution of 3-cyanobenzoyl chloride (660 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (450 mg, 51％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.31 (s, 1 H) , 8.26 (d, J ＝ 8.0 Hz, 1 H) , 7.83 (d, J ＝ 7.6 Hz, 1 H) , 7.58 (t, J ＝ 8.0 Hz, 1 H) , 4.39 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 1.92-1.85 (m, 2 H) , 1.76-1.69 (m, 2 H) .

Compound 12: 4- (3-cyanobenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-cyanobenzoate (400 mg, 1.83 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (330 mg, 77％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.31 (s, 1 H) , 8.26 (d, J ＝ 8.0 Hz, 1 H) , 7.85 (d, J ＝ 7.6 Hz, 1 H) , 7.59 (t, J ＝ 7.8 Hz, 1 H) , 4.43 (t, J ＝ 6.4 Hz, 2 H) , 2.56 (t, J ＝ 7.2 Hz, 2 H) , 2.18-2.11 (m, 2 H) .

Example 1-13

Intermediate Compound 13’ : 4-hydroxybutyl 4-tert-butylbenzoate

A solution of 4-tert-butylbenzoyl chloride (784 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (530 mg, 53％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (d, J ＝ 8.0 Hz, 2 H) , 7.45 (d, J ＝ 8.8 Hz, 2 H) , 4.35 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 1.91-1.83 (m, 2 H) , 1.76-1.71 (m, 2 H) , 1.34 (s, 9 H) .

Compound 13: 4- (4-tert-butylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-tert-butylbenzoate (450 mg, 1.8 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (370 mg, 79％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.96 (d, J ＝ 8.4 Hz, 2 H) , 7.45 (d, J ＝ 8.8 Hz, 2 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.15-2.06 (m, 2 H) , 1.34 (s, 9 H) .

Example 1-14

Intermediate Compound 14’ : 4-hydroxybutyl 3- (trifluoromethyl) benzoate

A solution of 3- (trifluoromethyl) benzoyl chloride (832 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 12 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (670 mg, 64％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.29 (s, 1 H) , 8.23 (d, J ＝ 8.0 Hz, 1 H) , 7.82 (d, J ＝ 8.0 Hz, 1 H) , 7.59 (t, J ＝ 7.8 Hz, 1 H) , 4.40 (t, J ＝ 6.4 Hz, 2 H) , 3.74 (t, J ＝ 6.6 Hz, 2 H) , 1.93-1.86 (m, 2 H) , 1.77-1.70 (m, 2 H) , 1.42 (br. s., 1 H) .

Compound 14: 4- (3- (trifluoromethyl) benzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-(trifluoromethyl) benzoate (600 mg, 2.29 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (400 mg, 63％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.29 (s, 1 H) , 8.22 (d, J ＝ 8.0 Hz, 1 H) , 7.82 (d, J ＝ 7.6 Hz, 1 H) , 7.59 (t, J ＝7.6 Hz, 1 H) , 4.43 (t, J ＝ 6.4 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.18-2.12 (m, 2 H) .

Example 1-15

Intermediate Compound 15’ : 4-hydroxybutyl 3, 4, 5-trimethoxybenzoate

A solution of 3, 4, 5-trimethoxybenzoyl chloride (920 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 12 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-4: 1 to yield the titled compound (700 mg, 62％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.29 (s, 2 H) , 4.35 (t, J ＝ 6.6 Hz, 2 H) , 3.90 (s, 9 H) , 3.77-3.69 (m, 2 H) , 1.92-1.84 (m, 2 H) , 1.75-1.68 (m, 2 H) , 1.48 (br. s., 1 H) .

Compound 15: 4- (3, 4, 5-trimethoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3, 4, 5-trimethoxybenzoate (600 mg, 2.11 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1-3: 1 to yield the titled compound (440 mg, 70％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.28 (s, 2 H) , 4.37 (t, J ＝ 6.4 Hz, 2 H) , 3.90 (s, 9 H) , 2.52 (t, J ＝ 7.2 Hz, 2 H) , 2.15-2.08 (m, 2 H) .

Example 1-16

Intermediate Compound 16’ : 4-hydroxybutyl 4-ethylbenzoate

A solution of 4-ethylbenzoyl chloride (500 mg, 2.98 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (534 mg, 5.93 mmol) and Et₃N (599 mg, 5.93 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-6: 1 to yield the titled compound (450 mg, 68％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (s, 1 H) , 7.94 (s, 1 H) , 7.27 (s, 1 H) , 7.25 (s, 1 H) , 4.35 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 2.70 (q, J ＝ 7.6 Hz, 2 H) , 1.90-1.83 (m, 2 H) , 1.77-1.70 (m, 2 H) , 1.34 (br. s., 1 H) , 1.25 (t, J ＝ 7.6 Hz, 3 H) .

Compound 16: 4- (4-ethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-ethylbenzoate (450 mg, 2.03 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (270 mg, 56％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 7.96 (s, 1 H) , 7.94 (s, 1 H) , 7.27 (s, 1 H) , 7.25 (s, 1 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 2.70 (q, J ＝ 7.6 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.15-2.09 (m, 2 H) , 1.25 (t, J ＝ 7.6 Hz, 3 H) .

Example 1-17

Intermediate Compound 17’ : 4-hydroxybutyl 2, 3-dimethylbenzoate

A solution of 2, 3-dimethylbenzoyl chloride (500 mg, 2.97 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (534 mg, 5.93 mmol) and Et₃N (599 mg, 5.93 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 3 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (390 mg, 59％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.61 (d, J ＝ 7.6 Hz, 1 H) , 7.28 (d, J ＝ 7.6 Hz, 1 H) , 7.13 (t, J ＝ 7.8 Hz, 1 H) , 4.34 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (t, J ＝ 6.0 Hz, 2 H) , 2.45 (s, 3 H) , 2.32 (s, 3 H) , 1.90-1.83 (m, 2 H) , 1.78-1.69 (m, 2 H) , 1.36 (br. s., 1 H) .

Compound 17: 4- (2, 3-dimethylbenzoyloxy) butanoic acid

Jones reagent was added in portions toa stirred mixture of 4-hydroxybutyl 2, 3-dimethylbenzoate (350 mg, 1.58 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-6: 1 to yield the titled compound (230 mg, 62％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.61 (d, J ＝ 7.6 Hz, 1 H) , 7.28 (d, J ＝ 7.2 Hz, 1 H) , 7.13 (t, J ＝ 7.6 Hz, 1 H) , 4.35 (t, J ＝ 6.2 Hz, 2 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.45 (s, 3 H) , 2.32 (s, 3 H) , 2.15-2.08 (m, 2 H) .

Example 1-18

Intermediate Compound 18’ : 4-hydroxybutyl 3, 5-dimethoxybenzoate

A solution of 3, 5-dimethoxybenzoyl chloride (500 mg, 2.49 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 3 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (430 mg, 68％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.18 (d, J ＝ 2.4 Hz, 2 H) , 6.65 (t, J ＝ 2.0 Hz, 1 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.83 (s, 6 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 1.90-1.83 (m, 2 H) , 1.76-1.69 (m, 2 H) .

Compound 18: 4- (3, 5-dimethoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3, 5-dimethoxybenzoate (400 mg, 1.57 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (200 mg, 47％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.16 (d, J ＝ 2.4 Hz, 2 H) , 6.64 (t, J ＝ 2.0 Hz, 1 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 3.82 (s, 6 H) , 2.52 (t, J ＝ 7.2 Hz, 2 H) , 2.14-2.07 (m, 2 H) .

Example 1-19

Intermediate Compound 19’ : 4-hydroxybutyl 3, 5-dimethylbenzoate

A solution of 3, 5-dimethylbenzoyl chloride (500 mg, 2.96 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (534 mg, 5.93 mmol) and Et₃N (599 mg, 5.93 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (400 mg, 61％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.65 (s, 2 H) , 7.19 (s, 1 H) , 4.35 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (s, 2 H) , 2.36 (s, 6 H) , 1.90-1.83 (m, 2 H) , 1.77-1.70 (m, 2 H) .

Compound 19: 4- (3, 5-dimethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3, 5-dimethylbenzoate (400 mg, 1.8 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (300 mg, 70％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.64 (s, 2 H) , 7.19 (s, 1 H) , 4.36 (t, J ＝ 6.0 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.36 (s, 6 H) , 2.15-2.08 (m, 2 H) .

Example 1-20

Intermediate Compound 20’ : 4-hydroxybutyl cinnamate

A solution of cinnamoyl chloride (664 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (455 mg, 52％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.69 (d, J ＝ 16.0 Hz, 1 H) , 7.54-7.52 (m, 2 H) , 7.39 (t, J ＝ 3.2 Hz, 3 H) , 6.44 (d, J ＝ 16.0 Hz, 1 H) , 4.25 (t, J ＝ 6.4 Hz, 2 H) , 3.72 (t, J ＝ 6.2 Hz, 2 H) , 1.85-1.78 (m, 2 H) , 1.73-1.66 (m, 2 H) , 1.44 (br. s., 1 H) .

Compound 20: (E) -4- (cinnamoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl cinnamate (400 mg, 1.81 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (370 mg, 87％) as colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 7.68 (d, J ＝ 16.0 Hz, 1 H) , 7.54-7.52 (m, 2 H) , 7.40-7.38 (m, 3 H) , 6.43 (d, J ＝ 16.0 Hz, 1 H) , 4.26 (t, J ＝ 6.2 Hz, 2 H) , 2.48 (t, J ＝ 7.2 Hz, 2 H) , 2.07-2.01 (m, 2 H) .

Example 1-21

Intermediate Compound 21’ : 4-hydroxybutyl 3-phenylpropanoate

A solution of 3-phenylpropanoyl chloride (672 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (370 mg, 42％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.31-7.27 (m, 2 H) , 7.21-7.19 (m, 3 H) , 4.10 (t, J ＝ 6.6 Hz, 2 H) , 3.65 (t, J ＝ 6.4 Hz, 2 H) , 2.95 (t, J ＝ 7.8 Hz, 2 H) , 2.63 (t, J ＝ 7.6 Hz, 2 H) , 1.73-1.66 (m, 2 H) , 1.60-1.54 (m, 2 H) , 1.33 (br. s., 1 H) .

Compound 21: 4- (3-phenylpropanoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-phenylpropanoate (300 mg, 1.35 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (277 mg, 87％) as colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 7.31-7.27 (m, 2 H) , 7.22-7.19 (m, 3 H) , 4.12 (t, J ＝ 6.2 Hz, 2 H) , 2.95 (t, J ＝ 7.8 Hz, 2 H) , 2.63 (t, J ＝ 7.6 Hz, 2 H) , 2.37 (t, J ＝ 7.4 Hz, 2 H) , 1.96-1.90 (m, 2 H) .

Example 1-22

Intermediate Compound 22’ : 4-hydroxybutyl pivalate

A solution of pivaloyl chloride (1.2 g, 10 mmol) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (2.7 g, 30 mmol) and Et₃N (2.02 g, 20 mmol) in DCM (30 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0～25 ℃ over 1 h. After that, the reaction mixture was diluted with H₂O (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (15 mL) . The combined organic phase was washed with brine (15 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 20: 1-5: 1 to yield the titled compound (1.5 g, 86％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.09 (t, J ＝ 6.0 Hz, 2 H) , 3.68 (t, J ＝ 6.4 Hz, 2 H) , 1.74-1.70 (m, 2 H) , 1.65-1.61 (m, 2 H) , 1.19 (s, 9 H) .

Compound 22: 4- (pivaloyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl pivalate (1.0 g, 5.75 mmol) and

(diatomaceous earth, 2 g) in acetone (20 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (20 mL) and then filtered. The filtered cake was washed with EA (10 mL) and the combined filtrate was washed with brine (5 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (700 mg, 65％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.11 (t, J ＝ 6.4 Hz, 2 H) , 2.46 (t, J ＝ 7.4 Hz, 2 H) , 2.02-1.95 (m, 2 H) , 1.19 (s, 9H) .

Example 1-23

Intermediate Compound 23’ : 4-hydroxybutyl 2-ethylbutanoate

A solution of 2-ethylbutanoyl chloride (500 mg, 3.7 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (669 mg, 7.43 mmol) and Et₃N (750 mg, 7.43 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 3 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (450 mg, 65％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.13 (t, J ＝ 6.4 Hz, 2 H) , 3.73-3.64 (m, 2 H) , 2.23-2.16 (m, 1 H) , 1.77-1.70 (m, 2 H) , 1.68-1.58 (m, 4 H) , 1.55-1.46 (m, 2 H) , 0.89 (t, J ＝ 7.4 Hz, 6 H) .

Compound 23: 4- (2-ethylbutanoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-ethylbutanoate (450 mg, 2.39 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (300 mg, 62％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.14 (t, J ＝ 6.2 Hz, 2 H) , 2.46 (t, J ＝ 7.6 Hz, 2 H) , 2.24-2.17 (m, 1 H) , 2.02-1.95 (m, 2 H) , 1.66-1.46 (m, 4 H) , 0.89 (t, J ＝ 7.4 Hz, 6 H) .

Example 1-24

Intermediate Compound 24’ : 4-hydroxybutyl 2-propylpentanoate

A solution of 2-propylpentanoyl chloride (1 g, 6.13 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (1107 mg, 12.3 mmol) and Et₃N (1242 mg, 12.3 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (700 mg, 53％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.11 (t, J ＝ 6.6 Hz, 2 H) , 3.69 (q, J ＝ 5.8 Hz, 2 H) , 2.39-2.32 (m, 1 H) , 1.77-1.69 (m, 2 H) , 1.68-1.60 (m, 3 H) , 1.58-1.53 (m, 1 H) , 1.45-1.36 (m, 3 H) , 1.33-1.24 (m, 4 H) , 0.89 (t, J ＝ 7.2 Hz, 6 H) .

Compound 24: 4- (2-propylpentanoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-propylpentanoate (500 mg, 2.31 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (160 mg, 30％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.12 (t, J ＝ 6.0 Hz, 2 H) , 2.46 (t, J ＝ 7.6 Hz, 2 H) , 2.41-2.31 (m, 1 H) , 2.01-1.95 (m, 2 H) , 1.63-1.54 (m, 2 H) , 1.45-1.37 (m, 2 H) , 1.33-1.24 (m, 4 H) , 0.89 (t, J ＝ 7.2 Hz, 6 H) .

Example 1-25

Intermediate Compound 25’ : 4-hydroxybutyl cyclopentanecarboxylate

A solution of cyclopentanecarbonyl chloride (528 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (520 mg, 70％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.10 (t, J ＝ 6.4 Hz, 2 H) , 3.68 (t, J ＝ 6.0 Hz, 2 H) , 2.76-2.68 (m, 1 H) , 1.92-1.62 (m, 10 H) , 1.60-1.53 (m, 2 H) , 1.41 (br. s., 1 H) .

Compound 25: 4- (cyclopentanecarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl cyclopentanecarboxylate (450 mg, 2.42 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (373 mg, 77％) as colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.12 (t, J ＝ 6.2 Hz, 2 H) , 2.76-2.68 (m, 1 H) , 2.45 (t, J ＝ 7.2 Hz, 2 H) , 2.01-1.94 (m, 2 H) , 1.92-1.84 (m, 2 H) , 1.82-1.65 (m, 4 H) , 1.61-1.50 (m, 2 H) .

Example 1-26

Intermediate Compound 26’ : 4-hydroxybutyl cyclohexanecarboxylate

A solution of cyclohexanecarbonyl chloride (584 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-3: 1 to yield the titled compound (440 mg, 55％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.08 (t, J ＝ 6.2 Hz, 2 H) , 3.66 (t, J ＝ 6.2 Hz, 2 H) , 2.32-2.24 (m, 1 H) , 1.88 (d, J ＝ 13.2 Hz, 2 H) , 1.76-1.58 (m, 8 H) , 1.48-1.37 (m, 2 H) , 1.31-1.15 (m, 3 H) .

Compound 26: 4- (cyclohexanecarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl cyclohexanecarboxylate (400 mg, 2 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (350 mg, 82％) as colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.11 (t, J ＝ 6.4 Hz, 2 H) , 2.45 (t, J ＝ 7.4 Hz, 2 H) , 2.29 (tt, J ＝ 3.6, 11.3 Hz, 1 H) , 2.01-1.94 (m, 2 H) , 1.91-1.87 (m, 2 H) , 1.76-1.69 (m, 2 H) , 1.65-1.62 (m, 1 H) , 1.48-1.38 (m, 2 H) , 1.33-1.19 (m, 3 H) .

Example 1-27

Intermediate Compound 27’ : 4-hydroxybutyl 2-acetoxyacetate

A solution of 2-chloro-2-oxoethyl acetate (544 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1-5: 1 to yield the titled compound (500 mg, 66％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.60 (s, 2 H) , 4.22 (t, J ＝ 6.4 Hz, 2 H) , 3.68 (dd, J ＝ 5.8, 10.6 Hz, 2 H) , 2.16 (s, 3 H) , 1.81-1.72 (m, 2 H) , 1.68-1.60 (m, 2 H) , 1.39 (br. s., 1 H) .

Compound 27: 4- (2-acetoxyacetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-acetoxyacetate (400 mg, 2.11 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1-3: 1 to yield the titled compound (370 mg, 86％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.60 (s, 2 H) , 4.24 (t, J ＝ 6.2 Hz, 2 H) , 2.46 (t, J ＝ 7.4 Hz, 2 H) , 2.16 (s, 3 H) , 2.04-1.97 (m, 2 H) .

Example 1-28

Intermediate Compound 28’ : ethyl (4-hydroxybutyl) carbonate

A solution of ethyl carbonochloridate (1 g, 9.17 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (1659 mg, 18.43 mmol) and Et₃N (1861 mg, 18.43 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (700 mg, 47％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.22-4.16 (m, 4 H) , 3.68 (q, J ＝ 5.8 Hz, 2 H) , 1.81-1.74 (m, 2 H) , 1.69-1.62 (m, 2 H) , 1.38 (t, J ＝ 5.0 Hz, 1 H) , 1.31 (t, J ＝ 7.0 Hz, 3 H) .

Compound 28: 4- (ethoxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of ethyl (4-hydroxybutyl) carbonate (500 mg, 3.09 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (70 mg, 13％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.22-4.17 (m, 4 H) , 2.50 (t, J ＝ 7.2 Hz, 2 H) , 2.05-1.98 (m, 2 H) , 1.31 (t, J ＝ 7.2 Hz, 3 H) .

Example 1-29

Intermediate Compound 29’ : 4-hydroxybutyl isopropyl carbonate

A solution of isopropyl carbonochloridate (10 ml, 1.0 M/L, 10 mmol) in DCM (10 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (1800 mg, 20 mmol) and Et₃N (2020 mg, 20 mmol) in DCM (20 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (1.58 g, 90％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.90-4.84 (m, 1 H) , 4.16 (t, J ＝ 6.6 Hz, 2 H) , 3.68 (t, J ＝ 6.2 Hz, 2 H) , 1.80-1.73 (m, 2 H) , 1.69-1.62 (m, 2 H) , 1.29 (d, J ＝ 5.6 Hz, 6 H) .

Compound 29: 4- (isopropoxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl isopropyl carbonate (800 mg, 4.55 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (260 mg, 30％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.90-4.84 (m, 1 H) , 4.18 (t, J ＝ 6.2 Hz, 2 H) , 2.50 (t, J ＝ 7.2 Hz, 2 H) , 2.05-1.97 (m, 2 H) , 1.30 (d, J ＝ 6.0 Hz, 6 H) .

Example 1-30

Intermediate Compound 30’ : 4-hydroxybutyl isobutyl carbonate

A solution of isobutyl carbonochloridate (544 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-6: 1 to yield the titled compound (250 mg, 33％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.18 (t, J ＝ 6.4 Hz, 2 H) , 3.91 (d, J ＝ 6.8 Hz, 2 H) , 3.69 (dd, J ＝ 5.4, 11.0 Hz, 2 H) , 1.81-1.75 (m, 3 H) , 1.70-1.62 (m, 2 H) , 0.96 (s, 3 H) , 0.94 (s, 3 H) .

Compound 30: 4- (isobutoxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl isobutyl carbonate (200 mg, 1.1 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1-3: 1 to yield the titled compound (110 mg, 51％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.20 (t, J ＝ 6.4 Hz, 2 H) , 3.92 (d, J ＝ 6.8 Hz, 2 H) , 2.49 (t, J ＝ 7.2 Hz, 2 H) , 2.06-1.93 (m, 3 H) , 0.96 (s, 3 H) , 0.94 (s, 3 H) .

Example 1-31

Intermediate Compound 31’ : benzyl (4-hydroxybutyl) carbonate

A solution of benzyl carbonochloridate (1 g, 5.86 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (1055 mg, 11.72 mmol) and Et₃N (1184 mg, 11.72 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 3 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (292 mg, 22％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.40-7.32 (m, 5 H) , 5.16 (s, 2 H) , 4.20 (t, J ＝ 6.6 Hz, 2 H) , 3.68 (q, J ＝ 6.0 Hz, 2 H) , 1.81-1.74 (m, 2 H) , 1.68-1.62 (m, 2 H) , 1.29 (t, J ＝ 5.4 Hz, 1 H) .

Compound 31: 4- (benzyloxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of benzyl (4-hydroxybutyl) carbonate (290 mg, 1.29 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (188 mg, 61％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.38-7.33 (m, 5 H) , 5.16 (s, 2 H) , 4.21 (t, J ＝ 6.2 Hz, 2 H) , 2.47 (t, J ＝ 7.2 Hz, 2 H) , 2.03-1.97 (m, 2 H) .

Example 1-32

Intermediate Compound 32’ : 4-hydroxybutyl phenyl carbonate

A solution of phenyl carbonochloridate (624 mg, 4 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol ) and Et₃N (505 mg, 5 mmol) in DCM (5 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ for over 1 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (333 mg, 40％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.39 (t, J ＝ 7.8 Hz, 2 H) , 7.26-7.23 (m, 1 H) , 7.18 (d, J ＝ 8.0 Hz, 2 H) , 4.30 (t, J ＝ 6.6 Hz, 2 H) , 3.72 (dd, J ＝ 6.2, 11.2 Hz, 2 H) , 1.89-1.82 (m, 2 H) , 1.75-1.68 (m, 2 H) , 1.35 (t, J ＝ 5.2 Hz, 1 H) .

Compound 32: 4- (phenoxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl phenyl carbonate (300 mg, 1.55 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-2: 1 to yield the titled compound (210 mg, 65％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.39 (t, J ＝ 8.0 Hz, 2 H) , 7.25 (t, J ＝ 7.2 Hz, 1 H) , 7.18 (d, J ＝ 8.0 Hz, 2 H) , 4.32 (t, J ＝ 6.2 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.13-2.06 (m, 2 H) .

Example 1-33

Intermediate Compound 33’ : 4-chlorophenyl (4-hydroxybutyl) carbonate

A solution of 4-chlorophenyl carbonochloridate (500 mg, 2.62 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (707 mg, 7.86 mmol ) and Et₃N (529 mg, 5.24 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (420 mg, 66％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.35 (d, J ＝ 9.2 Hz, 2 H) , 7.13 (d, J ＝ 9.2 Hz, 2 H) , 4.30 (t, J ＝ 6.4 Hz, 2 H) , 3.72 (t, J ＝ 6.2 Hz, 2 H) , 1.89-1.82 (m, 2 H) , 1.74-1.67 (m, 2 H) .

Compound 33: 4- ( (4-chlorophenoxy) carbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-chlorophenyl (4-hydroxybutyl) carbonate (400 mg, 1.64 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (220 mg, 52％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.35 (d, J ＝ 9.2 Hz, 2 H) , 7.13 (d, J ＝ 8.8 Hz, 2 H) , 4.32 (t, J ＝ 6.2 Hz, 2 H) , 2.55 (t, J ＝ 7.4 Hz, 2 H) , 2.13-2.06 (m, 2 H) .

Example 1-34

Intermediate Compound 34’ : 4-hydroxybutyl p-tolyl carbonate

A solution of p-tolyl carbonochloridate (500 mg， 2.94 mmol) in DCM (5 mL) was added dropwise during 10 min to a stirred solution of butane-1, 4-diol (794 mg, 8.82 mmol ) and Et₃N (594 mg, 5.88 mmol) in DCM (10 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (5 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (5 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (600 mg, 91％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.17 (d, J ＝ 8.4 Hz, 2 H) , 7.05 (d, J ＝ 8.4 Hz, 2 H) , 4.29 (t, J ＝ 6.8 Hz, 2 H) , 3.72 (t, J ＝ 6.2 Hz, 2 H) , 2.34 (s, 3 H) , 1.89-1.82 (m, 2 H) , 1.74-1.67 (m, 2 H) .

Compound 34: 4- (p-tolyloxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl p-tolyl carbonate (500 mg, 2.23 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (170 mg, 32％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.17 (d, J ＝ 8.4 Hz, 2 H) , 7.05 (d, J ＝ 8.0 Hz, 2 H) , 4.31 (t, J ＝ 6.2 Hz, 2 H) , 2.55 (t, J ＝ 7.2 Hz, 2 H) , 2.34 (s, 3 H) , 2.12-2.07 (m, 2 H) .

Scheme 3

Example 1-35

Intermediate Compound 35’ : tert-butyl (4-hydroxybutyl) carbonate

Di-tert-butyl dicarbonate [ (Boc) ₂O] (2.05 g, 9.4 mmol) and 4-dimethylaminopyridine (DMAP) (100 mg) was added to a stirred solution of butane-1, 4-diol (10 g, 111.11 mmol) in DCM (100 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (20 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (20 mL) . The combined organic phase was washed with saturated brine (30 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1 to yield the titled compound (1 g, 56％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.10 (t, J ＝ 6.6 Hz, 2 H) , 3.68 (q, J ＝ 6.0 Hz, 2 H) , 1.79-1.72 (m, 2 H) , 1.69-1.62 (m, 2 H) , 1.48 (s, 9 H) , 1.34 (t, J ＝ 5.2 Hz, 1 H) .

Compound 35: 4- (tert-butoxycarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of tert-butyl (4-hydroxybutyl) carbonate (800 mg, 4.21 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-6: 1 to yield the titled compound (500 mg, 58％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.12 (t, J ＝ 6.2 Hz, 2 H) , 2.49 (t, J ＝ 7.4 Hz, 2 H) , 2.03-1.96 (m, 2 H) , 1.48 (s, 9 H) .

Scheme 2

Example 1-36

Intermediate Compound 36’ : 4-hydroxybutyl 4-butoxybenzoate

4-butoxybenzoic acid (882 mg, 4.55 mmol) , N, N'-Dicyclohexylcarbodiimide (DCC) (1030 mg, 5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4- diol (450 mg, 5 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (500 mg, 41％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (d, J ＝ 8.4 Hz, 2 H) , 6.90 (d, J ＝ 9.2 Hz, 2 H) , 4.33 (t, J ＝ 6.2 Hz, 2 H) , 4.01 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 1.89-1.71 (m, 6 H) , 1.61 (br. s., 1 H) , 1.54-1.45 (m, 2 H) , 0.98 (t, J ＝ 7.2 Hz, 3 H) .

Compound 36: 4- (4-butoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-butoxybenzoate (450 mg, 1.69 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (200 mg, 42％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (d, J ＝ 8.8 Hz, 2 H) , 6.90 (d, J ＝ 8.8 Hz, 2 H) , 4.35 (t, J ＝ 6.2 Hz, 2 H) , 4.01 (t, J ＝ 6.4 Hz, 2 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.14-2.07 (m, 2 H) , 1.82-1.75 (m, 2 H) , 1.53-1.46 (m, 2 H) , 0.98 (t, J ＝ 7.4 Hz, 3 H) .

Example 1-37

Intermediate Compound 37’ : 4-hydroxybutyl 4-isopropylbenzoate

4-isopropylbenzoic acid (745 mg, 4.54 mmol) , DCC (1030 mg, 5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (450 mg, 5 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (400 mg, 37％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.96 (d, J ＝ 8.0 Hz, 2 H) , 7.29 (d, J ＝ 8.0 Hz, 2 H) , 4.35 (t, J ＝ 6.4 Hz, 2 H) , 3.76-3.69 (m, 2 H) , 2.99-2.93 (m, 1 H) , 1.90-1.83 (m, 2 H) , 1.76-1.69 (m, 2 H) , 1.40 (br. s., 1 H) , 1.27 (s, 3 H) , 1.26 (s, 3 H) .

Compound 37: 4- (4-isopropylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-isopropylbenzoate (350 mg, 1.48 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (200 mg, 54％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.95 (d, J ＝ 8.0 Hz, 2 H) , 7.29 (d, J ＝ 8.4 Hz, 2 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 2.99-2.92 (m, 1 H) , 2.54 (t, J ＝ 7.4 Hz, 2 H) , 2.15-2.08 (m, 2 H) , 1.27 (s, 3 H) , 1.25 (s, 3 H) .

Example 1-38

Intermediate Compound 38’ : 4-hydroxybutyl 3- (methylsulfonyl) benzoate

3- (methylsulfonyl) benzoic acid (505 mg, 2.53 mmol) , DCC (572 mg, 2.78 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (250 mg, 2.78 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 2: 1 to yield the titled compound (150 mg, 22％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.60 (s, 1 H) , 8.33 (d, J ＝ 8.0 Hz, 1 H) , 8.15 (d, J ＝ 8.0 Hz, 1 H) , 7.69 (t, J ＝ 7.8 Hz, 1 H) , 4.42 (t, J ＝ 6.6 Hz, 2 H) , 3.74 (q, J ＝ 6.0 Hz, 2 H) , 3.10 (s, 3 H) , 1.94-1.87 (m, 2 H) , 1.76-1.70 (m, 2 H) , 1.36 (t, J ＝ 5.0 Hz, 1 H) .

Compound 38: 4- (3- (methylsulfonyl) benzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-(methylsulfonyl) benzoate (150 mg, 0.55 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 2: 1 to yield the titled compound (70 mg, 44％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.59 (s, 1 H) , 8.32 (d, J ＝ 8.0 Hz, 1 H) , 8.15 (d, J ＝ 8.0 Hz, 1 H) , 7.69 (t, J ＝ 7.8 Hz, 1 H) , 4.44 (t, J ＝ 6.2 Hz, 2 H) , 3.11 (s, 3 H) , 2.55 (t, J ＝ 7.0 Hz, 2 H) , 2.20-2.14 (m, 2 H) .

Example 1-39

Intermediate Compound 39’ : 4-hydroxybutyl nicotinate

Nicotinic acid (615 mg, 5 mmol) , DCC (1133 mg, 5.5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (900 mg, 10 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 1: 1 to yield the titled compound (450 mg, 46％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 9.22 (d, J ＝ 1.6 Hz, 1 H) , 8.78 (dd, J ＝ 1.6, 4.8 Hz, 1 H) , 8.30 (td, J ＝ 1.6, 8.0 Hz, 1 H) , 7.40 (dd, J ＝ 5.0, 7.8 Hz, 1 H) , 4.41 (t, J ＝ 6.6 Hz, 2 H) , 3.74 (t, J ＝ 6.2 Hz, 2 H) , 1.93-1.86 (m, 2 H) , 1.77-1.70 (m, 2 H) , 1.46 (br. s., 1 H) .

Compound 39: 4- (nicotinoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl nicotinate (450 mg, 2.31 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 1: 1 to yield the titled compound (50 mg, 10％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 9.21 (d, J ＝ 1.6 Hz, 1 H) , 8.72 (dd, J ＝ 1.2, 4.8 Hz, 1 H) , 8.33 (td, J ＝ 1.6, 7.6 Hz, 1 H) , 7.40 (dd, J ＝ 5.0, 7.8 Hz, 1 H) , 4.45 (t, J ＝ 6.2 Hz, 2 H) , 2.56 (t, J ＝ 7.0 Hz, 2 H) , 2.21-2.15 (m, 2 H) .

Example 1-40

Intemediate Compound 40’ : 4-hydroxybutyl isonicotinate

To a stirred solution of butane-1, 4-diol (2.7 g, 30 mmol) in DCM (30 mL) was added isonicotinic acid (1.23 g, 10 mmol) , DCC (2.27 g, 11 mmol) and DMAP (122 mg) . The reaction was stirred at 25 ℃ for 8 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (15 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-2: 1 to yield the titled compound (1 g, 51％) as a pale yellow oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.76 (d, J ＝ 8.4 Hz, 2 H) , 7.84 (d, J ＝ 5.6 Hz, 2 H) , 4.39 (t, J ＝ 6.4 Hz, 2 H) , 3.72 (t, J ＝ 6.2 Hz, 2 H) , 1.92-1.85 (m, 2 H) , 1.75-1.70 (m, 2 H) .

Compound 40: 4- (isonicotinoyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl isonicotinate (900 mg, 4.62 mmol) and

(diatomaceous earth, 2 g) in acetone (30 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (50 mL) and then filtered. The filtered cake was washed with EA (50 mL) and the combined filtrate was washed with brine (5 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 2: 1 to yield the titled compound (70 mg, 7％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.55 (d, J ＝ 6.0 Hz, 2 H) , 7.86 (d, J ＝ 6.4 Hz, 2 H) , 4.49 (t, J ＝ 5.8 Hz, 2 H) , 2.53 (t, J ＝ 6.6 Hz, 2 H) , 2.23-2.17 (m, 2 H) .

Example 1-41

Intermediate Compound 41’ : 4-hydroxybutyl 3-methoxy-4-methylbenzoate

3-methoxy-4-methylbenzoic acid (500 mg, 3 mmol) , DCC (683 mg, 3.32 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (542 mg, 6 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (450 mg, 63％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.55 (d, J ＝ 7.6 Hz, 1 H) , 7.48 (s, 1 H) , 7.18 (d, J ＝ 8.0 Hz, 1 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.88 (s, 3 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 2.26 (s, 3 H) , 1.91-1.84 (m, 2 H) , 1.76-1.70 (m, 2 H) .

Compound 41: 4- (3-methoxy-4-methylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 3-methoxy-4-methylbenzoate (450 mg, 1.89 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 4: 1 to yield the titled compound (280 mg, 59％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.54 (d, J ＝ 7.6 Hz, 1 H) , 7.47 (s, 1 H) , 7.18 (d, J ＝ 7.6 Hz, 1 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 3.88 (s, 3 H) , 2.54 (t, J ＝ 7.4 Hz, 2 H) , 2.26 (s, 3 H) , 2.15-2.09 (m, 2 H) .

Example 1-42

Intermediate Compound 42’ : 4-hydroxybutyl 2, 6-dimethylbenzoate

2, 6-dimethylbenzoic acid (500 mg, 3.33 mmol) , DCC (755 mg, 3.67 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (600 mg, 6.67 mmol) in DCM (15 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with saturated brine (10 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (100 mg, 14％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.18 (t, J ＝ 7.6 Hz, 1 H) , 7.03 (d, J ＝ 8.0 Hz, 2 H) , 4.37 (t, J ＝ 6.6 Hz, 2 H) , 3.71 (t, J ＝ 6.4 Hz, 2 H) , 2.32 (s, 6 H) , 1.89-1.82 (m, 2 H) , 1.74-1.67 (m, 2 H) .

Compound 42: 4- (2, 6-dimethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2, 6-dimethylbenzoate (100 mg, 0.45 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (50 mg, 47％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.19 (t, J ＝ 7.4 Hz, 1 H) , 7.03 (d, J ＝ 7.6 Hz, 2 H) , 4.39 (t, J ＝ 6.4 Hz, 2 H) , 2.52 (t, J ＝ 7.4 Hz, 2 H) , 2.32 (s, 6 H) , 2.13-2.07 (m, 2 H) .

Example 1-43

Intermediate Compound 43’ : 4-hydroxybutyl 2-phenoxybenzoate

2-phenoxybenzoic acid (1070 mg, 5 mmol) , DCC (1133 mg, 5.5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (900 mg, 10 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1 to yield the titled compound (700 mg, 49％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.93 (dd, J ＝ 1.6, 8.0 Hz, 1 H) , 7.50-7.45 (m, 1 H) , 7.32 (t, J ＝ 7.8 Hz, 2 H) , 7.21 (t, J ＝ 7.6 Hz, 1 H) , 7.07 (t, J ＝ 7.4 Hz, 1 H) , 7.00 (d, J ＝ 8.0 Hz, 1 H) , 6.94 (d, J ＝ 7.6 Hz, 2 H) , 4.26 (t, J ＝ 6.2 Hz, 2 H) , 3.58 (s, 2 H) , 1.72-1.65 (m, 2 H) , 1.58-1.51 (m, 2 H) .

Compound 43: 4- (2-phenoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-phenoxybenzoate (700 mg, 2.45 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (400 mg, 54％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.92 (dd, J ＝ 1.6, 7.6 Hz, 1 H) , 7.50-7.46 (m, 1 H) , 7.31 (d, J ＝ 8.0 Hz, 2 H) , 7.20 (t, J ＝ 7.6 Hz, 1 H) , 7.07 (t, J ＝ 7.4 Hz, 1 H) , 7.00 (d, J ＝ 8.4 Hz, 1 H) , 6.93 (d, J ＝ 8.0 Hz, 2 H) , 4.27 (t, J ＝ 6.2 Hz, 2 H) , 2.36 (t, J ＝ 7.2 Hz, 2 H) , 1.96-1.90 (m, 2 H) .

Example 1-44

Intermediate Compound 44’ : 4-hydroxybutyl 2, 4-dimethylbenzoate

2, 4-dimethylbenzoic acid (750 mg, 5 mmol) , DCC (1133 mg, 5.5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (900 mg, 10 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1 to yield the titled compound (700 mg, 63％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.82 (d, J ＝ 7.6 Hz, 1 H) , 7.05-7.03 (m, 2 H) , 4.32 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (s, 2 H) , 2.57 (s, 3 H) , 2.35 (s, 3 H) , 1.89-1.82 (m, 2 H) , 1.76-1.69 (m, 2 H) .

Compound 44: 4- (2, 4-dimethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2, 4-dimethylbenzoate (700 mg, 3.15 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (550 mg, 74％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.82 (d, J ＝ 7.6 Hz, 1 H) , 7.05-7.03 (m, 2 H) , 4.34 (t, J ＝ 6.2 Hz, 2 H) , 2.57 (s, 3 H) , 2.54 (t, J ＝ 7.4 Hz, 2 H) , 2.35 (s, 3 H) , 2.14-2.08 (m, 2 H) .

Example 1-45

Intermediate Compound 45’ : 4-hydroxybutyl 2, 3-dimethoxybenzoate

2, 3-dimethoxybenzoic acid (910 mg, 5 mmol) , DCC (1133 mg, 5.5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (900 mg, 10 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1 to yield the titled compound (600 mg, 47％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.32 (dd, J ＝ 1.6, 7.2 Hz, 1 H) , 7.11-7.04 (m, 2 H) , 4.36 (t, J ＝ 6.4 Hz, 2 H) , 3.90 (s, 3 H) , 3.89 (s, 3 H) , 3.74-3.70 (m, 2 H) , 1.90-1.84 (m, 2 H) , 1.77-1.70 (m, 2 H) , 1.40 (t, J ＝ 4.8 Hz, 1 H) .

Compound 45: 4- (2, 3-dimethoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2, 3-dimethoxybenzoate (600 mg, 2.36 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (250 mg, 39％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.31 (dd, J ＝ 2.0, 7.2 Hz, 1 H) , 7.11-7.05 (m, 2 H) , 4.38 (t, J ＝ 6.2 Hz, 2 H) , 3.91 (s, 3 H) , 3.89 (s, 3 H) , 2.57 (t, J ＝ 7.4 Hz, 2 H) , 2.15-2.08 (m, 2 H) .

Example 1-46

Intermediate Compound 46’ : 4-hydroxybutyl 4-isopropoxybenzoate

4-isopropoxybenzoic acid (900 mg, 5 mmol) , DCC (1133 mg, 5.5 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (900 mg, 10 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (800 mg, 63％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.97 (d, J ＝ 8.8 Hz, 2 H) , 6.88 (d, J ＝ 9.2 Hz, 2 H) , 4.66-4.60 (m, 1 H) , 4.33 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (q, J ＝ 6.0 Hz, 2 H) , 1.89-1.82 (m, 2 H) , 1.76-1.69 (m, 2 H) , 1.37 (s, 3 H) , 1.35 (s, 3 H) .

Compound 46: 4- (4-isopropoxybenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-isopropoxybenzoate (800 mg, 3.17 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (380 mg, 45％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.96 (d, J ＝ 8.8 Hz, 2 H) , 6.88 (d, J ＝ 8.8 Hz, 2 H) , 4.66-4.60 (m, 1 H) , 4.35 (t, J ＝ 6.2 Hz, 2 H) , 2.54 (t, J ＝ 7.2 Hz, 2 H) , 2.15-2.08 (m, 2 H) , 1.37 (s, 3 H) , 1.35 (s, 3 H) .

Example 1-47

Intermediate Compound 47’ : 4-hydroxybutyl 2-ethylbenzoate

2, 6-dimethylbenzoic acid (500 mg, 3.33 mmol) , DCC (755 mg, 3.67 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (600 mg, 6.67 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 8: 1 to yield the titled compound (480 mg, 65％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.84 (d, J ＝ 8.0 Hz, 1 H) , 7.43 (t, J ＝ 7.4 Hz, 1 H) , 7.28-7.22 (m, 2 H) , 4.34 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (t, J ＝ 6.0 Hz, 2 H) , 2.98 (q, J ＝ 7.6 Hz, 2 H) , 1.91-1.84 (m, 2 H) , 1.77-1.70 (m, 2 H) , 1.24 (t, J ＝ 7.4 Hz, 3 H) .

Compound 47: 4- (2-ethylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2-ethylbenzoate (480 mg, 2.16 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (290 mg, 57％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 7.84 (d, J ＝ 8.0 Hz, 1 H) , 7.43 (d, J ＝ 7.2 Hz, 1 H) , 7.29-7.22 (m, 2 H) , 4.36 (t, J ＝ 6.2 Hz, 2 H) , 2.98 (q, J ＝ 7.6 Hz, 2 H) , 2.55 (t, J ＝ 7.2 Hz, 2 H) , 2.15-2.08 (m, 2 H) , 1.24 (t, J ＝ 7.6 Hz, 3 H) .

Example 1-48

Intermediate Compound 48’ : 4-hydroxybutyl 4-benzoylbenzoate

4-benzoylbenzoic acid (500 mg, 2.21 mmol) , DCC (501 mg, 2.44 mmol) and DMAP (5 mg) was added to a stirred solution of butane-1, 4-diol (398 mg, 4.42 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (400 mg, 61％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.15 (d, J ＝ 8.4 Hz, 2 H) , 7.85-7.80 (m, 4 H) , 7.62 (t, J ＝ 7.6 Hz, 1 H) , 7.50 (t, J ＝ 7.6 Hz, 2 H) , 4.41 (t, J ＝ 6.4 Hz, 2 H) , 3.75 (t, J ＝ 6.4 Hz, 2 H) , 1.94-1.87 (m, 2 H) , 1.79-1.72 (m, 2 H) .

Compound 48: 4- (4-benzoylbenzoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 4-benzoylbenzoate (400 mg, 1.34 mmol) and (diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (280 mg, 67％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.14 (d, J ＝ 8.4 Hz, 2 H) , 7.85-7.80 (m, 4 H) , 7.62 (t, J ＝ 7.6 Hz, 1 H) , 7.50 (t, J ＝ 7.6 Hz, 2 H) , 4.44 (t, J ＝ 6.2 Hz, 2 H) , 2.57 (t, J ＝ 7.2 Hz, 2 H) , 2.19-2.12 (m, 2 H) .

Example 1-49

Intemediate Compound 49’ : 4-hydroxybutyl methyl phthalate

To a stirred solution of butane-1, 4-diol (1.35 g, 15 mmol) in DCM (30 mL) was added 2- (methoxycarbonyl) benzoic acid (900 mg, 5 mmol) , DCC (1.13 g, 5.5 mmol) and DMAP (60 mg) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (15 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-2: 1 to yield the titled compound (1 g, 79％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.72-7.68 (m, 2 H) , 7.55-7.51 (m, 2 H) , 4.34 (t, J ＝ 6.6 Hz, 2 H) , 3.89 (s, 3H) , 3.68 (t, J ＝ 6.4 Hz, 2 H) , 1.83-1.77 (m, 3 H) , 1.70-1.65 (m, 2 H) .

Compound 49: 4- (2- (methoxycarbonyl) benzoyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl methyl phthalate (900 mg, 3.57 mmol) and

(diatomaceous earth, 2 g) in acetone (20 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (10 mL) and the combined filtrate was washed with brine (3 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-1: 1 to yield the titled compound (800 mg, 84％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 7.74-7.70 (m, 2 H) , 7.55-7.53 (m, 2 H) , 4.37 (t, J ＝ 6.2 Hz, 2 H) , 3.91 (s, 3 H) , 2.51 (t, J ＝ 7.2 Hz, 2 H) , 2.10-2.03 (m, 2 H) .

Example 1-50

Intemediate Compound 50’ : 4-hydroxybutyl methyl terephthalate

To a stirred solution of butane-1, 4-diol (1.5 g, 16.67 mmol) in DCM (20 mL) was added 4- (methoxycarbonyl) benzoic acid (1 g, 5.56 mmol) , DCC (1258 mg, 6.11 mmol) and DMAP (10 mg) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (750 mg, 54％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.10 (s, 4 H) , 4.39 (t, J ＝ 6.6 Hz, 2 H) , 3.95 (s, 3 H) , 3.74 (t, J ＝ 6.4 Hz, 2 H) , 1.92-1.87 (m, 2 H) , 1.77-1.72 (m, 2 H) .

Compound 50: 4- (4- (methoxycarbonyl) benzoyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl methyl terephthalate (700 mg, 2.78 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (2 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to yield the titled compound (400 mg, 54％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.09 (s, 4 H) , 4.41 (t, J ＝ 6.2 Hz, 2 H) , 3.95 (s, 3 H) , 2.55 (t, J ＝ 7.2 Hz, 2 H) , 2.18-2.11 (m, 2 H) .

Example 1-51

Intermediate Compound 51’ : 4-hydroxybutyl (²H₅) benzoate

(²H₅) benzoic acid (300 mg, 2.36 mmol) , DCC (535 mg, 2.6 mmol) and DMAP (10 mg) was added to a stirred solution of butane-1, 4-diol (425 mg, 4.72 mmol) in DCM (20 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (320 mg, 68％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.37 (t, J ＝ 6.4 Hz, 2 H) , 3.74 (t, J ＝ 6.4 Hz, 2 H) , 1.91-1.84 (m, 2 H) , 1.78-1.71 (m, 2 H) .

Compound 51: 4- ( (²H₅) phenylcarbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl (²H₅) benzoate (300 mg, 1.51 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (220 mg, 69％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 4.39 (t, J ＝ 6.2 Hz, 2 H) , 2.56 (t, J ＝ 7.4 Hz, 2 H) , 2.17-2.10 (m, 2 H) .

Example 1-52

Intermediate Compound 52’ : 4-hydroxybutyl thiazole-2-carboxylate

To a stirred solution of butane-1, 4-diol (1.05 g, 11.66 mmol) in DCM (10 mL) was added thiazole-2-carboxylic acid (500 mg, 3.88 mmol) , DCC (879 mg, 4.27 mmol) and DMAP (50 mg) . The reaction was stirred at 25 ℃ for 8 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-2: 1 to yield the titled compound (300 mg, 38％) as a pale yellow oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.03 (d, J ＝ 2.8 Hz, 1 H) , 7.64 (d, J ＝ 3.2 Hz, 1 H) , 4.47 (t, J ＝ 6.6 Hz, 2 H) , 3.73 (t, J ＝ 6.2 Hz, 2 H) , 1.97-1.90 (m, 2 H) , 1.77-1.70 (m, 2 H) .

Compound 52: 4- (thiazole-2-carbonyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl thiazole-2-carboxylate (300 mg, 1.49 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (2 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-1: 1 to yield the titled compound (200 mg, 62％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.06 (d, J ＝ 2.8 Hz, 1 H) , 7.67 (d, J ＝ 3.2 Hz, 1 H) , 4.49 (t, J ＝ 6.2 Hz, 2 H) , 2.58 (t, J ＝ 7.2 Hz, 2 H) , 2.19-2.12 (m, 2 H) .

Example 1-53

Intermediate Compound 53’ : 4-hydroxybutyl furan-3-carboxylate

To a stirred solution of butane-1, 4-diol (540 mg, 6 mmol) in DCM (10 mL) was added furan-3-carboxylic acid (224 mg, 2 mmol) , DCC (453 mg, 2.2 mmol) and DMAP (24 mg) . The reaction was stirred at 25 ℃ for 12 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (270 mg, 73％) as a pale yellow oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.00 (s, 1 H) , 7.42 (s, 1 H) , 6.73 (s, 1 H) , 4.28 (t, J ＝ 6.4 Hz, 2 H) , 3.70 (t, J ＝ 6.4 Hz, 2 H) , 1.83-1.67 (m, 4 H) .

Compound 53: 4- (furan-3-carbonyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl furan-3-carboxylate (750 mg, 4.09 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (2 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 3: 1 to yield the titled compound (600 mg, 74％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.01 (s, 1 H) , 7.42 (s, 1 H) , 6.73 (s, 1 H) , 4.31 (t, J ＝ 6.2 Hz, 2 H) , 2.51 (t, J ＝ 7.4 Hz, 2 H) , 2.12-2.05 (m, 2 H) .

Example 1-54

Intermediate Compound 54’ : 4-hydroxybutyl thiophene-3-carboxylate

To a stirred solution of butane-1, 4-diol (2.1 g, 23.33 mmol) in DCM (50 mL) was added thiophene-3-carboxylic acid (1 g, 7.81 mmol) , DCC (1.77 g, 8.59 mmol) and DMAP (10 mg) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (5 mL) . The combined organic phase was washed with brine (10 mL) , dried over Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 7: 1 to afford the crude product, which was further purified by prep-TLC with Hex/EA ＝ 1: 1 to yield the pure titled compound (600 mg, 38％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.10 (d, J ＝ 2.0 Hz, 1 H) , 7.53 (d, J ＝ 5.2 Hz, 1 H) , 7.31 (dd, J ＝ 3.2, 5.2 Hz, 1 H) , 4.32 (t, J ＝ 6.4 Hz, 2 H) , 3.73 (t, J ＝ 6.4 Hz, 2 H) , 1.90-1.80 (m, 2 H) , 1.76-1.68 (m, 2 H) .

Compound 54: 4- (thiophene-3-carbonyloxy) butanoic acid

To a stirred mixture of 4-hydroxybutyl thiophene-3-carboxylate (400 mg, 2 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃ was added Jones reagent in portions. The reaction proceeded at 0 ℃ over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with brine (2 mL x 2) , dried over Na₂SO₄ and concentrated. The residue was purified by prep-HPLC to yield the titled compound (100 mg, 23％) as crystalline solids. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.10 (d, J ＝ 2.0 Hz, 1 H) , 7.52 (d, J ＝ 5.2 Hz, 1 H) , 7.31 (dd, J ＝ 3.0, 5.0 Hz, 1 H) , 4.34 (t, J ＝ 6.2 Hz, 2 H) , 2.53 (t, J ＝ 7.2 Hz, 2 H) , 2.13-2.07 (m, 2 H) .

Example 1-55

Intermediate Compound 55’ : (S) -1-tert-butyl 2- (4-hydroxybutyl) pyrrolidine-1, 2-dicarboxylate

(S) -1- (tert-butoxycarbonyl) pyrrolidine-2-carboxylic acid (2 g, 9.3 mmol) , DCC (2108 mg, 10.23 mmol) and DMAP (50 mg) was added to a stirred solution of butane-1, 4-diol (1674 mg, 18.6 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 3 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝5: 1 to yield the titled compound (1.4 g, 52％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 4.32-4.12 (m, 3 H) , 3.71-3.62 (m, 2 H) , 3.58-3.35 (m, 2 H) , 2.27-2.16 (m, 1 H) , 2.02-1.60 (m, 8 H) , 1.46 (s, 4 H) , 1.41 (s, 5 H) .

Compound 55: (S) -4- (1- (tert-butoxycarbonyl) pyrrolidine-2-carbonyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of (S) -1-tert-butyl 2- (4-hydroxybutyl) pyrrolidine-1, 2-dicarboxylate (400 mg, 1.39 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with DCM/MeOH ＝ 120: 1 to yield the titled compound (200 mg, 48％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.40-4.32 (m, 1 H) , 4.26-4.07 (m, 2 H) , 3.58-3.35 (m, 2 H) , 2.45 (t, J ＝ 7.0 Hz, 2 H) , 2.33-2.12 (m, 2 H) , 2.01-1.83 (m, 4 H) , 1.46 (s, 5 H) , 1.46 (s, 4 H) .

Example 1-56

Intermediate Compound 56’ : 4-hydroxybutyl 2- (tert-butoxycarbonylamino) acetate

2- (tert-butoxycarbonylamino) acetic acid (340 mg, 1.94 mmol) , DCC (440 mg, 2.14 mmol) and DMAP (5 mg) was added to a stirred solution of butane-1, 4-diol (350 mg, 3.89 mmol) in DCM (30 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (200 mg, 42％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 5.00 (br. s., 1 H) , 4.20 (t, J ＝ 6.6 Hz, 2 H) , 3.90 (d, J ＝ 5.2 Hz, 2 H) , 3.68 (q, J ＝ 6.0 Hz, 2 H) , 1.79-1.72 (m, 2 H) , 1.67-1.62 (m, 2 H) , 1.45 (s, 9 H) , 1.37-1.34 (m, 1 H) .

Compound 56: 4- (2- (tert-butoxycarbonylamino) acetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 4-hydroxybutyl 2- (tert-butoxycarbonylamino) acetate (200 mg, 0.81 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a flash column (silica gel, DCM/MeOH ＝ 100: 1 to yield the titled compound (150 mg, 71％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 5.03 (br. s., 1 H) , 4.23 (t, J ＝ 6.2 Hz, 2 H) , 3.90 (d, J ＝ 5.2 Hz, 2 H) , 2.45 (t, J ＝ 7.2 Hz, 2 H) , 2.05-1.98 (m, 2 H) , 1.45 (s, 9 H) .

Example 1-57

Compound 57: 4- (2-aminoacetoxy) butanoic acid

A solution of 4- (2- (tert-butoxycarbonylamino) acetoxy) butanoic acid (150 mg, 0.57 mmol) in saturated HCl/EA (1.5 mL) was stirred at 25 ℃ for 24 h. After that, the reaction mixture was filtered and the resulting precipitate was collected, washed with Et₂O (0.5 mL) , dried in vacuo to yield the titled compound (82 mg, 89％) as a white solid. ¹H NMR was performed at 400MHz with CD₃OD as solvent to characterize the titled compound, results are as follows: δ ＝ 4.30 (t, J ＝ 6.4 Hz, 2 H) , 3.84 (s, 2 H) , 2.42 (t, J ＝ 7.2 Hz, 2 H) , 2.03-1.94 (m, 2 H) .

Example 1-58

Intermediate Compound 58’ : (S) -4-hydroxybutyl 2- (tert-butoxycarbonylamino) -3-phenylpropanoate

(S) -2- (tert-butoxycarbonylamino) -3-phenylpropanoic acid (1 g, 3.37 mmol) , DCC (855 mg, 4.15 mmol) and DMAP (10 mg) was added to a stirred solution of butane-1, 4- diol (679 mg, 7.54 mmol) in DCM (20 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (700 mg, 55％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.32-7.27 (m, 2 H) , 7.26-7.21 (m, 1 H) , 7.14 (d, J ＝ 6.8 Hz, 2 H) , 4.97 (d, J ＝ 8.0 Hz, 1 H) , 4.58-4.53 (m, 1 H) , 4.19-4.08 (m, 2 H) , 3.64 (q, J ＝ 5.6 Hz, 2 H) , 3.07 (t, J ＝ 4.8 Hz, 2 H) , 1.72-1.65 (m, 2 H) , 1.56-1.51 (m, 2 H) , 1.42 (s, 9 H) .

Intermediate Compound 58” : (S) -4- (2- (tert-butoxycarbonylamino) -3-phenylpropanoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of (S) -4-hydroxybutyl 2- (tert-butoxycarbonylamino) -3-phenylpropanoate (600 mg, 1.78 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (220 mg, 35％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.34-7.27 (m, 2 H) , 7.26-7.20 (m, 1 H) , 7.14 (d, J ＝ 6.8 Hz, 2 H) , 4.99 (d, J ＝ 8.0 Hz, 1 H) , 4.61-4.51 (m, 1 H) , 4.22-4.09 (m, 2 H) , 3.06 (d, J ＝ 6.0 Hz, 2 H) , 2.34 (t, J ＝ 7.2 Hz, 2 H) , 1.97-1.89 (m, 2 H) , 1.42 (s, 9 H) .

Compound 58: (S) -4- (2-amino-3-phenylpropanoyloxy) butanoic acid

A solution of (S) -4- (2- (tert-butoxycarbonylamino) -3-phenylpropanoyloxy) butanoic acid (180 mg, 0.51 mmol) in saturated HCl/EA (2 mL) stirred at 25 ℃ for 24 h. After that, the reaction mixture was filtered and the resulting precipitate was collected, washed with Et₂O (0.5 mL) , dried in vacuo to yield the titled compound (100 mg, 78％) as a white solid. ¹H NMR was performed at 400MHz with CD₃OD as solvent to characterize the titled compound, results are as follows: δ ＝ 7.41-7.31 (m, 3 H) , 7.27-7.25 (m, 2 H) , 4.30 (t, J ＝ 7.0 Hz, 1 H) , 4.26-4.19 (m, 2 H) , 3.25-3.15 (m, 2 H) , 2.28 (t, J ＝ 7.2 Hz, 2 H) , 1.92-1.86 (m, 2 H) .

Example 1-59

Intermediate Compound 59’ : (S) -4-hydroxybutyl 2- (tert-butoxycarbonylamino) -3-methylbutanoate

(S) -2- (tert-butoxycarbonylamino) -3-methylbutanoic acid (1 g, 4.61 mmol) , DCC (1044 mg, 5.07 mmol) and DMAP (10 mg) was added to a stirred solution of butane-1, 4-diol (829 mg, 9.21 mmol) in DCM (20 mL) . The reaction was stirred at 25 ℃ for 16 h. After that, the reaction mixture was diluted with saturated aqueous NH₄Cl (10 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (15 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝5:1 to yield the titled compound (700 mg, 53％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ＝ 5.07 (d, J ＝ 8.8 Hz, 1 H) , 4.16-4.11 (m, 3 H) , 3.62 (t, J ＝ 6.2 Hz, 2 H) , 2.32 (br. s., 1 H) , 2.12-2.04 (m, 1 H) , 1.75-1.68 (m, 2 H) , 1.62-1.56 (m, 2 H) , 1.40 (s, 9 H) , 0.92 (d, J ＝ 7.2 Hz, 3 H) , 0.85 (d, J ＝ 7.2 Hz, 3 H) .

Intermediate Compound 59”: (S) -4- (2- (tert-butoxycarbonylamino) -3-methylbutanoyloxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of (S) -4-hydroxybutyl 2- (tert-butoxycarbonylamino) -3-methylbutanoate (500 mg, 1.73 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (170 mg, 32％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 5.03 (d, J ＝ 9.2 Hz, 1 H) , 4.30 -4.24 (m, 1 H) , 4.22-4.13 (m, 2 H) , 2.46 (t, J ＝ 7.4 Hz, 2 H) , 2.16-2.08 (m, 1 H) , 2.06-1.96 (m, 2 H) , 1.45 (s, 9 H) , 0.96 (d, J ＝ 6.8 Hz, 3 H) , 0.89 (d, J ＝ 6.4 Hz, 3 H) .

Compound 59: (S) -4- (2-amino-3-methylbutanoyloxy) butanoic acid

A solution of (S) -4- (2- (tert-butoxycarbonylamino) -3-methylbutanoyloxy) butanoic acid (104 mg, 0.34 mmol) in saturated HCl/EA (1.5 mL) stirred at 25 ℃ for 24 h. After that, the reaction mixture was filtered and the resulting precipitate was collected, washed with Et₂O (0.5 mL) , dried in vacuo to yield the titled compound (50 mg, 71％) as a white solid. ¹H NMR was performed at 400MHz with CD₃OD as solvent to characterize the titled compound, results are as follows: δ ＝ 4.33-4.26 (m, 2 H) , 3.92 (d, J ＝ 4.8 Hz, 1 H) , 2.42 (t, J ＝ 7.2 Hz, 2 H) , 2.34-2.25 (m, 1 H) , 2.05-1.94 (m, 2 H) , 1.06 (d, J ＝ 6.8 Hz, 6 H) .

Scheme 4

Example 1-60

Intermediate Compound 60’ : 4-hydroxybutyl 2-chloroacetate

A solution of 2-chloroacetyl chloride (5 g, 44.25 mmol) in DCM (10 mL) dropwise during 10 min was added to a stirred solution of butane-1, 4-diol (19.9 g, 221.11 mmol) and Et₃N (8.9 g, 88.5 mmol) in DCM (40 mL) at 0 ℃. The reaction was allowed to warm up gradually and stirred at 0-25 ℃ over 16 h. After that, the reaction mixture was diluted with H₂O (20 mL) and stirred for 5 min. The aqueous phase was separated and extracted with DCM (20 mL) . The combined organic phase was washed with saturated brine (30 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1 to yield the titled compound (3.2 g, 44％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 4.24 (t, J ＝ 6.6 Hz, 2 H) , 4.07 (s, 2 H) , 3.69 (t, J ＝ 6.4 Hz, 2 H) , 1.82-1.75 (m, 2 H) , 1.68-1.61 (m, 2 H) .

Intermediate Compound 60”: 2- (4-hydroxybutoxy) -2-oxoethyl 2-ethylbenzoate

Et₃N (365 mg, 3.61 mmol) and 4-hydroxybutyl 2-chloroacetate (300 mg, 1.81 mmol) was added to a stirred solution of 2-ethylbenzoic acid (542 mg, 3.61 mmol) in acetone (10 mL) . The reaction was stirred at 50 ℃ for 5 h. After that, the reaction mixture was partitioned between DCM (20 mL) and H₂O (10 mL) . The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (20 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (175 mg, 35％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.02-7.95 (m, 1 H) , 7.49-7.44 (m, 1 H) , 7.32-7.24 (m, 2 H) , 4.83 (s, 2 H) , 4.25 (t, J ＝ 6.4 Hz, 2 H) , 3.67 (t, J ＝ 6.4 Hz, 2 H) , 3.08-2.97 (m, 2 H) , 1.81-1.74 (m, 2 H) , 1.67-1.60 (m, 2 H) , 1.28-1.22 (m, 3 H) .

Compound 60: 4- (2- (2-ethylbenzoyloxy) acetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 2- (4-hydroxybutoxy) -2-oxoethyl 2-ethylbenzoate (170 mg, 0.61 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (90 mg, 51％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.96 (d, J ＝ 7.6 Hz, 1 H) , 7.46 (t, J ＝ 7.0 Hz, 1 H) , 7.31-7.25 (m, 2 H) , 4.83 (s, 2 H) , 4.28 (t, J ＝ 6.2 Hz, 2 H) , 3.00 (q, J ＝ 7.6 Hz, 2 H) , 2.47 (t, J ＝ 7.4 Hz, 2 H) , 2.06-1.99 (m, 2 H) , 1.24 (t, J ＝ 7.4 Hz, 3 H) .

Example 1-61

Intermediate Compound 61’ : 2- (4-hydroxybutoxy)-2-oxoethyl 2, 4-dimethylbenzoate

Et₃N (364 mg, 3.6 mmol) and 4-hydroxybutyl 2-chloroacetate (300 mg, 1.81 mmol) to a stirred solution of 2, 4-dimethylbenzoic acid (405 mg, 2.7 mmol) in acetone (10 mL) . The reaction was stirred at 50 ℃ for 5 h. After that, the reaction mixture was partitioned between DCM (20 mL) and H₂O (10 mL) . The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (20 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (350 mg, 69％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.92 (d, J ＝ 8.0 Hz, 1 H) , 7.08-7.06 (m, 2 H) , 4.81 (s, 2 H) , 4.24 (t, J ＝ 6.6 Hz, 2 H) , 3.67 (t, J ＝ 6.2 Hz, 2 H) , 2.59 (s, 3 H) , 2.36 (s, 3 H) , 1.80-1.73 (m, 2 H) , 1.66-1.60 (m, 2 H) , 1.44 (br. s., 1 H) .

Compound 61: 4- (2- (2, 4-dimethylbenzoyloxy) acetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 2- (4-hydroxybutoxy) -2-oxoethyl 2, 4-dimethylbenzoate (300 mg, 1.07 mmol) and

(diatomaceous earth, 2 g) in acetone (10 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (150 mg, 48％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.92 (d, J ＝ 8.4 Hz, 1 H) , 7.18-7.06 (m, 2 H) , 4.81 (s, 2 H) , 4.27 (t, J ＝ 6.2 Hz, 2 H) , 2.58 (s, 3 H) , 2.47 (t, J ＝ 7.4 Hz, 2 H) , 2.36 (s, 3 H) , 2.06-2.00 (m, 2 H) .

Example 1-62

Intermediate Compound 62’ : 2- (4-hydroxybutoxy) -2-oxoethyl 2, 3-dimethoxybenzoate

Et₃N (364 mg, 3.6 mmol) and 4-hydroxybutyl 2-chloroacetate (300 mg, 1.81 mmol) was added to a stirred solution of 2, 3-dimethoxybenzoic acid (655 mg, 3.6 mmol) in acetone (10 mL) . The reaction was stirred at 50 ℃ for 5 h. After that, the reaction mixture was partitioned between DCM (20 mL) and H₂O (10 mL) . The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (20 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 2: 1 to yield the titled compound (200 mg, 35％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.43 (dd, J ＝ 2.4, 6.8 Hz, 1 H) , 7.14-7.08 (m, 2 H) , 4.84 (s, 2 H) , 4.25 (t, J ＝ 6.5 Hz, 2 H) , 3.93 (s, 3 H) , 3.89 (s, 3 H) , 3.67 (t, J ＝ 6.2 Hz, 2 H) , 1.81-1.74 (m, 2 H) , 1.67-1.60 (m, 2 H) .

Compound 62: 4- (2- (2, 3-dimethoxybenzoyloxy) acetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 2- (4-hydroxybutoxy) -2-oxoethyl 2, 3-dimethoxybenzoate (200 mg, 0.64 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 5: 1-2: 1 to yield the titled compound (100 mg, 48％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 7.43 (dd, J ＝ 2.6, 7.0 Hz, 1 H) , 7.14-7.09 (m, 2 H) , 4.84 (s, 2 H) , 4.27 (t, J ＝ 6.0 Hz, 2 H) , 3.93 (s, 3 H) , 3.89 (s, 3 H) , 2.47 (t, J ＝ 7.2 Hz, 2 H) , 2.06-1.99 (m, 2 H) .

Example 1-63

Intermediate Compound 63’ : 2- (4-hydroxybutoxy) -2-oxoethyl benzoate

Et₃N (364 mg, 3.6 mmol) and 4-hydroxybutyl 2-chloroacetate (300 mg, 1.81 mmol) was added to a stirred solution of benzoic acid (439 mg, 3.6 mmol) in acetone (10 mL) . The reaction was stirred at 50 ℃ for 5 h. After that, the reaction mixture was partitioned between DCM (20 mL) and H₂O (10 mL) . The aqueous phase was separated and extracted with DCM (10 mL) . The combined organic phase was washed with saturated brine (20 mL) , dried over anhydrous Na₂SO₄ and evaporated. The residue was purified by a silica gel flash column with Hex/EA ＝ 6: 1 to yield the titled compound (260 mg, 57％) as a colorless oil. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.10 (d, J ＝ 7.2 Hz, 2 H) , 7.60 (t, J ＝ 7.4 Hz, 1 H) , 7.47 (t, J ＝ 7.8 Hz, 2 H) , 4.85 (s, 2 H) , 4.25 (t, J ＝ 6.6 Hz, 2 H) , 3.67 (t, J ＝ 6.2 Hz, 2 H) , 1.80-1.73 (m, 2 H) , 1.66-1.59 (m, 2 H) .

Compound 63: 4- (2- (benzoyloxy) acetoxy) butanoic acid

Jones reagent was added in portions to a stirred mixture of 2- (4-hydroxybutoxy) -2-oxoethyl benzoate (250 mg, 0.99 mmol) and

(diatomaceous earth, 2 g) in acetone (5 mL) at 0 ℃. The reaction proceeded at 0 ℃ for over 1 h and the reaction progress was monitored by TLC. After completion, the reaction was quenched with drops of iPrOH, diluted with EA (10 mL) and then filtered. The filtered cake was washed with EA (5 mL) and the combined filtrate was washed with saturated brine (2 mL x 2) , dried over anhydrous Na₂SO₄ and concentrated. The residue was purified by a silica gel flash column with Hex/EA ＝ 10: 1-5: 1 to yield the titled compound (140 mg, 53％) as a white solid. ¹H NMR was performed at 400MHz with CDCl₃ as solvent to characterize the titled compound, results are as follows: δ ＝ 8.10 (d, J ＝ 7.2 Hz, 2 H) , 7.60 (t, J ＝ 7.4 Hz, 1 H) , 7.47 (t, J ＝ 7.8 Hz, 2 H) , 4.85 (s, 2 H) , 4.27 (t, J ＝ 6.2 Hz, 2 H) , 2.46 (t, J ＝ 7.4 Hz, 2 H) , 2.05-1.98 (m, 2 H) .

EXAMPLE 2: Metabolic stability assay of the test compounds

The protocol for rat liver homogenate metabolic stability assay is employed to determine the half-life (T_1/2) of the compounds of the invention and their releasing efficiency of converting from the prodrugs to GHB in vitro.

For GHB releasing efficiency assay, rat livers were obtained from male Sprague-Dawley rats and cut into small pieces after weighing the rat liver. The tissue pieces were washed and homogenized immediately with 4 ℃ buffer solution (containing 0.25 M sucrose, 10 mM Tris and 1 mM EDTA, pH ＝ 7.4) on ice in a weight ratio of 1: 3. Each test compound (at final concentration of 20 μM, in duplicate) was mixed with approximately 2 ml liver homogenate and pre-incubated at 37 ℃ for 3 min. Reactions at 37 ℃ were terminated after the pre-incubation at various time points (0, 5, 10, 20, 40 min) by taking 100 μl aliquot out of each sample and mixing with triple volume of ice-cold methanol containing internal standard. After vortex, the mixture was centrifuged at 3500 rpm for 5 min. The supernatant was then injected onto the liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) system for measurement of test compounds, internal standard and GHB sodium salt. GHB sodium salt and all other compounds were monitored using negative and positive ion mode, respectively. The measurement results were then used for calculation of half-life (T_1/2) of the test compounds and their conversion efficiency into GHB in liver.

Table 1: Half life and GHB formation efficiency of the test compounds in rat liver homogenate after incubation

The in vitro GHB releasing efficiency assay employing rat liver homogenates had shown that prodrug compounds could be converted to release GHB with variable formation efficiencies, which suggested they would be converted into GHB in the systemic circulation after being administered to rats.

EXAMPLE 3: Pharmacokinetic studies

For pharmacokinetic studies, male Sprague-Dawley rats were housed individually and fasted overnight before use. The animal dosing experiments were carried out in accordance to the National Institutes of Health Guide to the Care and Use of Laboratory Animals and the Animal Welfare Act. For GHB sodium salt, a single dose of 50 mg/kg was administered to each rat in two groups (n ＝ 3/group) via intravenous (IV) and oral (PO) administration, respectively. The vehicle used for GHB sodium salt is saline water. For other test compounds, a single dose of each test compound was administered to each rat orally (n ＝ 3/group) . The dosage of each test compound is listed in the Table 2. The vehicle used for dosing test compounds was 0.5％ (v/v) carboxy methyl cellulose. Blood samples were collected at specified time-points following both IV and PO administration to individual rats. Blood samples were clotted on ice immediately, plasma samples were then isolated by centrifugation and stored frozen (-80 ℃) until further analysis. The concentrations of GHB and all other test compounds were individually determined by HPLC-MS/MS assay. Various pharmacokinetic parameters were calculated using WinNonlin software (To inventor: please provide reference or vendor) . To quantify the bioconversion efficiency of the test compounds in the circulation system, the relative bioavailability of GHB sodium salt after PO administration was calculated. The values of relative bioavailability were expressed as the ratio of the AUC of GHB converted from the test compounds versus the AUC of GHB sodium salt administrated via IV alone adjusted by dose. Data are shown as below in Table 2. Table 2: Rat pharmacokinetic parameters of GHB sodium salt and representative compounds

Note*: measured and calculated based on GHB, **Relative bioavailability

EXAMPLE 4: Colonic absorption in rat

The purpose of the colonic absorption trial is to evaluate the effect of the improved transport properties of prodrugs on the resulting pharmacokinetics and distribution of GHB. The study is to be conducted by the following general procedures: GHB and the compounds of the present invetion are each administered to groups of three to seven male rats through a bolus injection directly into the colon via the indwelling cannula. Following dosing, blood samples are obtained at intervals over 24 h and are immediately processed to obtain the plasma at 4 ℃. The concentrations of GHB and all other test compounds are individually determined by HPLC-MS/MS assay. The compounds of the present application demonstrate more effective colonic absorption than GHB.

While the invention has been particularly shown and described with reference to specific embodiments (some of which are preferred embodiments) , it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as disclosed herein.

Claims

A compound of Formula I:

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

B is - (O) R¹, -R² (OCO) R³, substituted or unsubstituted C_5-10 aryl, C_1-12 alkyl, C_5-12 aralkyl, C_2-12 alkenyl, C_6-12 aralkenyl, C_2-12 alkynyl, C_3-8 cycloalkyl, 3-10 membered heterocyclic alkyl, or 5-10 membered heterocyclic aryl, wherein the one or more substituents are selected from the group consisting of -R⁴-S-R⁵, halogen, hydroxyl, cyano, amino, substituted amino, amino protection group, mono-, di-or tri-halo-C_1-6 alkyl, C_1-12 alkyl, C_2-12 alkenyl, C_2-12 alkynyl, C_1-12 alkoxy, C_5-10 aryl, C_3-8 cycloalkyl, C_1-12 alkylsulfonyl, 3-8 membered heterocyclic alkyl, 3-10 membered heterocyclic aryl, C_5-10 aryloxyl, C_5-10 arylcarbonyl, C_1-6 alkylcarbonyloxyl or C_1-4 alkyloxycarbonyl；

wherein

R¹ and R³ are independently C_1-12 alkyl, C_2-12 alkenyl, C_5-12 aralkyl, C_6-12 aralkenyl, C_2-12 alkynyl, C_5-10 aryl, C_3-8 cycloalkyl, 3-10 membered heterocyclic alkyl, or 5-10 membered heterocyclic aryl, which can be optionally mono-or independently multi-substituted by -R⁴-S-R⁵, halogen, hydroxyl, cyano, amino, substituted amino, C_1-12 alkyl, C_2-12 alkenyl, C_2-12 alkynyl, C_5-10 aryl, C_1-12 alkoxy, C_3-8 cycloalkyl, 3-8 membered heterocyclic alkyl, or 3-10 membered heterocyclic aryl, C_1-4 alkylsulfonyl, C_5-10 aryloxyl, C_5-10 arylcarbonyl or C_1-4 alkyloxycarbonyl；

R² is C_1-6 alkyl；

R⁴ is bond, C_1-6 alkyl, C_5-10 aryl, or C_5-12 aralkyl, and R⁵ is hydrogen or C_1-12 alkyl.
The compound of claim 1, wherein the compound has the chemical structure shown in Formula (IA) :

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

R_a, R_b, R_c, R_d and R_e are independently hydrogen, halogen, C_1-12 alkyl, C_1-12 alkoxy, cyano, C_1-12 alkylsulfonyl, C_1-6 alkylcarbonyloxyl, C_1-4 alkyloxycarbonyl, mono-, di-or tri-halo-C_1-6 alkyl, C_5-10 aryloxyl or C_5-10 arylcarbonyl； and

at least one of R_a, R_b, R_c, R_d and R_e is not protium.
The compound of claim 2, wherein R_b, R_c, R_d are all hydrogen, and R_e and R_a are independently hydrogen, halogen, C_1-3 alkyl, C_1-3 alkoxy_, cyano, C_1-3 alkylsulfonyl, C_1-3 alkylcarbonyloxyl, C_1-3 alkyloxycarbonyl, or mono-, di-or tri-halo-C_1-3 alkyl.
The compound of claim 3, wherein one of R_e and R_a is hydrogen.
The compound of claim 1, wherein the compound has the chemical structure shown in Formula (IB) :

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

R_g is hydrogen, C_1-6 alkyl, phenyl, or phenylmethyl which is optionally mono-or independently multi-substituted by halogen, hydroxyl, methylthio, C_1-4 alkyl, or C_5-8 aryl； and R_h and R_f are independently hydrogen, C_1-6 alkyl or an amino protecting group； or

R_f and R_g together with C, O, N or S atom form a 4-8 membered heterocyclic alkyl, and R_h is hydrogen, C_1-6 alkyl or an amino protecting group.
The compound of claim 5, wherein when R_f or R_h is an amino protection group, R_g is not isopropyl or benzyl.
The compound of claim 5, wherein R_g is not isopropyl or benzyl.
The compound of claim 1, wherein the compound has the chemical structure shown in Formula (IC) :

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

R¹ is C_1-8 alkyl, C_5-8 aryl, or C_5-12 aralkyl which are each optionally mono-or independently multi-substituted by halogen, cyano, hydroxyl, C_1-6 alkyl or C_1-4 alkoxy.
The compound of claim 8, wherein R¹ is
and R_1a and R_1b are independently hydrogen, C_1-12 alkyl, C_1-4 alkoxy or halogen.
The compound of claim 8, wherein R¹ is
and R_1c is hydrogen, C_1-12 alkyl or halogen.
The compound of claim 1, wherein the compound has the chemical structure shown in Formula (ID) :

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

R² is - (CH₂) _m-, wherein m＝1-6；

R³ is C_1-12 alkyl, C_5-8 aryl, 3-8 membered heterocyclic alkyl, or 5-8 membered heterocyclic aryl, which are each optionally mono-or independently multi-substituted by halogen, C_1-6 alkyl or C_1-6 alkoxy.
The compound of claim 11, wherein the compound has the chemical structure shown in Formula (ID-1) :

or a pharmaceutically acceptable salt, ester, hydrate, or solvate thereof, wherein,

R_3a, R_3b, R_3c, R_3d and R_3e are independently hydrogen, halogen, C_1-6 alkyl, or C_1-6 alkoxy.
The compound of claim 1, wherein B is:

C_1-8 alkyl substituted with C_2-6 alkyl, aryl or amino group and B is not linear alkyl； or

C_2-6 alkenyl substituted with C_1-6 alkyl, aryl or amino group； or

substituted or unsubstituted C_3-8 cycloalkyl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl； or

substituted or unsubstituted 3-8 membered heterocyclic alkyl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl； or

substituted or unsubstituted 5-8 membered heterocyclic aryl, wherein the substituent is selected from the group consisting of halogen, hydroxyl, C_1-6 alkyl.
The compound of claim 13, wherein B is –CHR₆R₇, wherein R₆ and R₇ are independently selected from the group consisting of C_2-6 alkyl, aryl and amino group,

optionally, R₆ and R₇ can be cyclized to form a C_3-8 cycloalkyl or R₆ and R₇ together with the O, N or S atom form a 3-8 membered heterocyclic alkyl.
The compound of claim 1, selected from the group consisting of
The compound of any of claims 1 to 15, wherein the molecular weight of the compound is no more than 450 Da, or 150-450 Da, or 150-300 Da.
The compound of any of claims 1-16, wherein the hydrogen includes its isotopes and the isotopes are protium and deuterium.
A pharmaceutical composition comprising one or more compounds according to any one of claims 1 to 17, and a pharmaceutically acceptable carrier.
The pharmaceutical composition of claim 18, wherein the pharmaceutical composition is formulated in a sustained released form.
The compound of any of claims 1 to 17, wherein the compound can sequentially convert to gamma-hydroxybutyric acid and enter into human circulatory system through a biological process after oral administration.
Use of one or more compounds according to any one of claims 1 to 17 in the manufacture of a medicament for treating a disease, wherein the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease.
A method of treating a disease, comprising administering to a subject an effective amount of one or more compounds according to any one of claims 1 to 17, wherein the disease is narcolepsy, excessive daytime sleepiness, cataplexy, neurodegenerative disease, sleep disturbance syndrome, fibromyalgia, chronic fatigue, schizophenia, binge eating disorder, Parkinson disease, tardive dyskinesia, or Alzheimer's disease.
The method of claim 22, wherein the disease is excessive daytime sleepiness or cataplexy associated with narcolepsy.
The method of claim 22, wherein the administration is conducted no more than two times per day.
The method of claim 22, wherein the administration is via oral, nasal, intravenous, subcutaneous, sublingual, or intramuscular administration.
The method of claim 22, wherein the dosage of the compound is within the range of 1-18 g.