HK1062018A - Process for preparing 4"-substituted-9-deoxo-9a-aza-9a-homoerythromycin a derivatives - Google Patents

Description

Process for the preparation of 4' -substituted-9-deoxo-9 a-aza-9 a-homoerythromycin A derivatives

Background

The present invention relates to a process for the preparation of C-4 "substituted derivatives of 9-deoxy-9 a-aza-9 a-homoerythromycin (homoerythromycins) a, hereinafter referred to as" azalides "(s), which are useful as antibacterial and antiprotozoal agents in mammals, including humans, as well as in fish and birds. The invention also relates to processes for the preparation of stable intermediates of the subject azalides, as well as to crystalline salts of intermediates in the processes for the preparation of the subject azalides. The present invention also relates to pharmaceutical compositions containing the novel compounds prepared by the subject methods; the invention also relates to methods of treating bacterial and protozoal infections in mammals, fish and birds by administering to mammals, fish and birds in need of such treatment the novel compounds prepared by the subject methods.

Macrolide antibiotics are known to be useful in the treatment of a broad spectrum of bacterial and protozoal infections in mammals, fish and birds. Such antibiotics include various derivatives of erythromycin A, such as the commercially available azaerythromycin (azithromycin), which is mentioned in U.S. Pat. Nos. 4,474,768 and 4,517,359, the entire contents of which are incorporated herein by reference. As will be described below, the macrolide compounds of the present invention have potent activity against various bacterial infections and protozoa infections, as well as azaerythromycin and other macrolide antibiotics.

The industrial scale production of the subject azalides has several difficulties including, but not limited to: low yields, unstable certain synthetic intermediates, and the presence of undesirable impurities.

Summary of The Invention

The present invention relates to a process for preparing a compound of formula 1 or a pharmaceutically acceptable salt thereof,

the method comprises the following steps: a compound of formula 2

And formula HNR⁸R¹⁵In an organic solvent comprising isopropanol, at a temperature of at least about 40 ℃;

wherein:

R³is-CH₂NR⁸R¹⁵；

R⁸Is C₁-C₁₀An alkyl group; and

R¹⁵is H or C₁-C₁₀An alkyl group.

In a preferred embodiment of the process, R⁸Is propyl, R¹⁵Is H. In a particularly preferred embodiment, R⁸Is n-propyl, R¹⁵Is H.

In a particularly preferred embodiment, the organic solvent is isopropanol.

In another preferred embodiment, the present invention relates to a process for the preparation of a compound of formula 1 a:

the process is carried out by reacting a compound of formula 2 with n-propylamine in an organic solvent containing isopropanol at a temperature of at least about 40 ℃. In a particularly preferred embodiment, the organic solvent is an isopropanol.

It should be noted that: as used herein, unless otherwise indicated, the terms "solution" and "mixture" are used interchangeably and do not take into account the dispersion of the components therein. As used herein, unless otherwise indicated, the phrase "organic solvent containing isopropanol" refers to a non-aqueous solvent or a mixture of non-aqueous solvents, wherein at least one of the solvents is isopropanol. In the present application, "compounds of formula 1" include compounds of formula 1 and compounds of formula 1 a. The compound of formula 1a is a particularly preferred embodiment of the compound of formula 1, as this applies to all embodiments and preferred embodiments of the process described herein.

In embodiments of the methods described herein, the reaction temperature is less than about 95 ℃; in preferred embodiments thereof, the reaction temperature is less than about 80 ℃; in a more preferred embodiment thereof, the reaction temperature is from about 50 to about 76 ℃. In a particularly preferred embodiment thereof, the reaction temperature is from about 50 ℃ to about 55 ℃.

In a preferred embodiment of the process described herein, the reaction is carried out at near atmospheric pressure. In this application, the term "atmospheric pressure" refers to the normal range of pressure of meteorological atmospheric pressure at altitude, while the term "pressurized" refers to pressures above atmospheric pressure. In another embodiment of the process described herein, the reaction is carried out under pressure. In another embodiment of the invention, triethylamine may be added to the isopropanol.

In addition to the preferred embodiments herein, the reaction of a compound of formula 2 with an amine in a solvent free of isopropanol has been successful to produce a compound of formula 1. Thus, the invention also relates to a process for the preparation of the compound of formula 1 by reacting a compound of formula 2 with HNR⁸R¹⁵In an organic solvent selected from: benzyl alcohol, acetone, methyl isobutyl ketone, DMSO, t-butanol, n-butanol, diisopropyl ether, a mixture of MTBE and DMF, and combinations of these solvents, wherein the reaction temperature is at least about 40 ℃. The reaction may be carried out under pressure, but is preferably carried out at about normal pressure. In another embodiment, a catalytic amount of a Lewis acid may be added to accelerate the reaction. In one embodiment, examples of lewis acids include: magnesium bromide, potassium iodide, lithium perchlorate, magnesium perchlorate, lithium tetrafluoroborate, pyridine hydrochloride or tetrabutylammonium iodide. Preferably, the lewis acid is magnesium bromide.

In an embodiment of the process described herein, the molar amount of amine is at least 5 times the molar amount of the compound of formula 2. In another embodiment of the process described herein, the concentration of the amine in isopropanol is at least about 5 molar by weight. In a particularly preferred embodiment, the concentration of n-propylamine in isopropanol is from about 6 to 7 Mol by weight.

In one embodiment of the above process, the compound of formula 2 is reacted with the amine for at least about 24 hours. In a preferred embodiment thereof, the molar amount of amine is at least 5 times the molar amount of the compound of formula 2, and the compound of formula 2 is reacted with the amine for at least about 24 hours. In a more preferred embodiment thereof, the reaction temperature is from about 50 ℃ to about 80 ℃. In a more preferred embodiment thereof, the molar amount of amine is about 20 times the molar amount of the compound of formula 2, the concentration of amine in isopropanol is about 6 moles, and the compound of formula 2 is reacted with the amine for at least about 24 hours at a temperature of about 50 ℃ to about 55 ℃.

Another embodiment of the methods described herein further comprises crystallizing the free base of the compound of formula 1. In one embodiment, the free base of the compound of formula 1 is crystallized from an aqueous solvent mixture. In a preferred embodiment thereof, the aqueous solvent mixture comprises water and a non-aqueous solvent, wherein the non-aqueous solvent is selected from the group consisting of: methanol, ethanol, isopropanol, and acetone. In another embodiment, the free base of the compound of formula 1 is derived from organic (C)₆-C₁₀) Crystallization from an alkane solvent, or from a mixture of said organic alkane solvents. In a preferred embodiment thereof, the crystallization method of the compound of formula 1 is: the compound is first heated with an alkane solvent and then cooled until crystals form. In its preferred embodiment, organic (C)₆-C₁₀) The alkane solvent is selected from heptane or octane, most preferably heptane. In another embodiment, described below, the free base is prepared from an acid addition salt of a compound of formula 1. It should be understood that: unless otherwise indicated, "alkane" as used herein includes straight, branched or cyclic saturated monovalent hydrocarbons or mixtures thereof.

In another embodiment of the process described herein, the acid addition salts of the compounds of formula 1 are prepared by: treating the compound of formula 1 with a solution containing an acid in a water-soluble solvent. In a preferred embodiment thereof, the acid solution is added to a solution containing the compound of formula 1 and water. In a preferred embodiment thereof, the acid is phosphoric acid, L-tartaric acid or dibenzoyl-D-tartaric acid. In a particularly preferred embodiment thereof, the acid is phosphoric acid. In another more preferred embodiment thereof, the solvent comprises ethanol. In another preferred embodiment thereof, the above process further comprises isolating an acid addition salt of the compound of formula 1.

In one embodiment, the process produces a compound of formula 1 having a purity of at least 90%, more preferably at least 95%, and most preferably at least 98%. In particular, the purity of the compound of formula 1 prepared by the process of the present invention allows the compound of formula 1 to be used in the formulation of parenteral formulations. The requirements for parenteral formulations are well known in the art, for example: particularly high purity, small particles in solution, sterile formulation and pyrogen removal (see Remington's pharmaceutical sciences, Mack Publishing Company, Easton, Pa., 18th Edition, Gennaro eds (1990), p. 1545-1580).

In another preferred embodiment thereof, the above method further comprises: treating an acid addition salt of a compound of formula 1 with a base in a mixture of water and a non-polar solvent to give a free base of the compound of formula 1. In a more preferred embodiment thereof, the base is a dibasic carbonate; in a particularly preferred embodiment, the dibasic carbonate is potassium carbonate. In another more preferred embodiment thereof, the non-polar solvent is dichloromethane. In another embodiment, the method further comprises crystallizing the free base of the compound of formula 1 as described above, and further includes related other embodiments as described above.

The present invention also relates to a process for preparing a compound of formula 2, comprising:

(a) a free base of a compound of formula 3

Reacting with a sulfonium methylide ion;

(b) terminating the reaction of step (a) with an aqueous weak acid solution and partitioning the product into a non-aqueous solution; and

(c) deprotecting the product of step (b) to provide a compound of formula 2; wherein R is⁴Is a hydroxyl protecting group.

In one embodiment, the above method further comprises isolating the compound of formula 2. In a preferred embodiment thereof, the compound of formula 2 is isolated in the form of a hydrate, more preferably in the form of a monohydrate. In one embodiment thereof, the water content is determined by the Karl-Fischer method. In one embodiment thereof. Obtaining a hydrate from a mixture comprising a compound of formula 2 and a solvent or solvent mixture selected from: acetone, acetone/water, acetone/heptane and MTBE/heptane. In other embodiments, the compound of formula 2 is isolated as the acetate, L-tartrate, or dibenzoyl-D-tartrate salt.

The present invention relates to a monohydrate of the compound of formula 2. In a preferred embodiment of the above process, R⁴Is benzyloxycarbonyl.

In another preferred embodiment of the above process, the reaction temperature of step (a) is from about-80 ℃ to about-45 ℃.

In another embodiment of the above process, the free base of the compound of formula 3 is prepared from an acid addition salt of the compound of formula 3. In a preferred embodiment thereof, the acid addition salt is a trifluoroacetic acid addition salt. In another embodiment of the above process, the acid addition salt of the compound of formula 3 is selected from: dibenzoyl-D-tartrate, L-tartrate or phosphate. The acid addition salts of the compounds disclosed herein are readily prepared in conventional manner.

In an embodiment of the above process, the methylenesulfonium is dimethylmethylenesulfonium. In its preferred embodiment, dimethylmethylenesulfonium is prepared by reacting a halide or sulfonate salt of trimethylsulfonium with a strong base. In a more preferred embodiment thereof, a halide of trimethylsulfonium, preferably trimethylsulfonium bromide, is used. In another more preferred embodiment thereof, the halide of trimethylsulfonium is reacted with a strong base in an inert organic solvent or a mixture thereof. In a particularly preferred embodiment thereof, the inert organic solvent is an ethereal solvent, most preferably tetrahydrofuran or a mixture of tetrahydrofuran and dichloromethane.

In one embodiment, step (c) comprises catalytic hydrogenation, wherein R is⁴Is benzyloxycarbonyl. In a preferred embodiment thereof, the catalyst for the hydrogenation reaction is a palladium on carbon catalyst. In a particularly preferred embodiment, the palladium on carbon catalyst is 10% Pd/C (Johnson-Matthey model A402028-10). In another embodiment of step (C), the product of step (b) is deprotected by catalytic transfer hydrogenation, preferably with ammonium formate, Pd/C in methanol. In another embodiment, the product of step (b) is treated with Fuller's earth prior to hydrogenation. Suitable solvents for the hydrogenation reaction are acetone, ethyl acetate, THF, MTBE, isopropanol, ethanol and methanol. The preferred solvent is acetone.

The invention also relates to 2' -benzyloxycarbonyl protected compounds of formula II:

which is obtained by omitting step (c) by the above-mentioned method.

The present invention relates to a process for preparing a compound of formula 3 by oxidizing the C-4' hydroxyl group of a compound of formula 4,

wherein R is⁴Is a hydroxyl protecting group.

In one embodiment, the oxidation reaction proceeds as follows: dimethyl sulfoxide ("DMSO") is added to a solution containing the compound of formula 4 and a solvent, the mixture is cooled to about-70 ℃, trifluoroacetic anhydride is added, and then triethylamine is added. In another embodiment, DMSO is activated with oxalyl chloride (with or without trimethylsilyl acetamide), polyphosphoric acid, pyridine-SO 3, or acetic anhydride. In another embodiment thereof, the reaction temperature is maintained between-70 ℃ and-60 ℃ during the addition of trifluoroacetic anhydride. In another embodiment thereof, the solvent is dichloromethane. One particular advantage of the above method is that: DMSO is activated in situ in the presence of a reactive alcohol, which avoids the formation of usual impurities during the oxidation reaction of activated DMSO, which usually involves introducing the alcohol into a solution containing activated DMSO.

In one embodiment, the above method further comprises isolating an acid addition salt of the compound of formula 3. In a preferred embodiment, the acid addition salt is a dibenzoyl-D-tartrate salt or a phosphate salt. In a particularly preferred embodiment, the present invention relates to a process for the preparation of a trifluoroacetic acid addition salt of a compound of formula 3, comprising: crystallizing the resulting acid addition salt by treating the compound of formula 3 with trifluoroacetic acid;

wherein R is⁴Is a hydroxyl protecting group.

In a preferred embodiment of the above process, R⁴Is benzyloxycarbonyl.

In another preferred embodiment of the above process, the acid addition salt is crystallized from isopropanol.

In another preferred embodiment of the above process, the acid addition salt is crystallized from a mixture of dichloromethane and methyl tert-butyl ether.

The trifluoroacetic acid addition salts prepared by the process of the present invention are not pharmaceutically acceptable salts, but are particularly highly pure and very stable, thereby enabling storage and transportation of suitable starting materials in the industrial production of the compounds of formula 1.

In one embodiment of the above process, the compound of formula 4 is prepared by protecting the 2' -hydroxy group of the compound of formula 5.

In a preferred embodiment, the 2' -hydroxyl group is protected with a benzyloxycarbonyl group. In another preferred embodiment, the compound of formula 5 is reacted with at least 2 molar equivalents of benzyl chloroformate. In a more preferred embodiment, the reaction is carried out in dichloromethane. In a more preferred embodiment, the volume of dichloromethane is at least 1.5 times the excess volume relative to the volume of starting material. The invention also relates to trifluoroacetic acid addition salts of compounds of formula 3, wherein R⁴Is benzyloxycarbonyl:

in a preferred embodiment thereof, the salt has the structure shown in formula 3a

Wherein R is⁴Is benzyloxycarbonyl.

The invention also relates to the dibenzoyl-D-tartrate salt of the compound of formula 3, wherein R⁴Is benzyloxycarbonyl.

Unless otherwise indicated, the term "hydroxy protecting group" as used herein includes: acetyl, benzyloxycarbonyl, and various hydroxyl protecting Groups familiar to those skilled In the art, as described In T.W.Greene, P.G.M.Wuts, "Protective Groups In Organic Synthesis," (J.Wiley&Sons, 1991). Preferably, the hydroxyl protecting group R⁴Is benzyloxycarbonyl ("CBZ").

Unless otherwise indicated, the term "halogen" as used herein includes fluorine, chlorine or bromine; the term "halide" refers to the corresponding anion of fluorine, chlorine or bromine, respectively.

Unless otherwise indicated, the term "alkyl" as used herein includes straight, branched or cyclic saturated monovalent hydrocarbon radicals or mixtures thereof.

Unless otherwise indicated, the term "pharmaceutically acceptable salt" as used herein includes acid or base salts which may be present in the compounds of the present invention. The compounds prepared by the process of the present invention are themselves basic compounds, in particular the free bases of the compounds of formula 1, which are capable of forming a variety of salts with various inorganic and organic acids. Acids which can be used for the preparation of pharmaceutically acceptable acid addition salts of the above-mentioned basic compounds of the invention are those which form non-toxic acid addition salts, examples of which are salts containing a pharmaceutically acceptable anion, such as hydrochloride, hydrobromide, hydroiodide, nitrate, sulphate, bisulphate, phosphate, acid phosphate, isonicotinate, acetate, lactate, salicylate, citrate, acid citrate, tartrate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisate, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, glutamate, methanesulphonate, ethanesulphonate, benzenesulphonate, p-toluenesulphonate and pamoate [ i.e. 1, 1' -methylene-bis- (2-hydroxy-3-naphthoate) ]. In addition to the acids mentioned above, the amino group-containing compounds prepared by the process of the present invention can form pharmaceutically acceptable salts with various amino acids.

The term "treating" as used herein, unless otherwise indicated, includes the treatment or prevention of bacterial or protozoal infections provided in the methods of the present invention.

The present invention includes compounds of the present invention, pharmaceutically acceptable salts thereof, wherein 1 or more hydrogen, carbon, nitrogen or other atoms are replaced by isotopes thereof. Such compounds can be used as research and diagnostic tools in metabolic pharmacokinetic studies and binding assays.

Detailed Description

The process of the present invention can be carried out according to schemes 1 to 4 below, and the following description, wherein substituents R are as follows unless otherwise indicated³、R⁴、R⁸And R¹⁵As defined above.

Scheme 1

Scheme 2

Scheme 3

The compounds of formula 4 used as starting materials for the process of the present invention are readily prepared from compounds of formula 5 (i.e., R)⁴Compounds that are hydrogen) see WO 98/56802 and US4,328,334, 4,474,768 and 4,517,359, all of which are incorporated herein by reference in their entirety.

The above-described arrangements are given for illustration only and will be described in further detail below and in the examples. In scheme 1, an epoxide of formula 2 is converted to an amine of formula 1, wherein R³is-CH₂NR¹⁵R⁸Wherein R is¹⁵And R⁸As described above. In the most preferred embodiment of the invention, the amine is n-propylamine, i.e., R⁸Is n-propyl, R¹⁵Is hydrogen.

To prepare the compound of formula 1, it is preferred to use a compound of formula HNR in a suitable solvent (e.g., isopropanol or an organic solvent mixture containing isopropanol)¹⁵R⁸Treatment of a Compound of formula 2 wherein R¹⁵And R⁸As defined above, the reaction is preferably carried out at about 40 ℃ to about 95 ℃. The most preferred reaction temperature is from about 50 ℃ to about 55 ℃, although higher temperatures, such as 76 ℃, may also be used. The most preferred pressure for carrying out the reaction is near atmospheric pressure, however, the reaction can also be carried out under pressure.

In one of the above-described methods for ring opening of epoxides of formula 2 (see WO 98/56802, examples 48, 50, 51 and 70), where the 2' -hydroxy group is protected, preparation of the compound of formula 1 (or the compound of formula 1 a) requires simultaneous amination of the epoxide and hydrolysis of the protecting group. This method is not a preferred method because hydrolysis during the epoxide opening step is ineffective and isolation of the compound of formula 1 becomes more difficult due to the presence of unhydrolyzed protecting groups and other impurities. In another of the foregoing processes, the compound of formula 2 (wherein the 2' -hydroxyl group is not protected) is reacted with pure alkylamine, i.e., without an organic solvent. In this case, the reaction is carried out slowly at the normal boiling temperature of n-propylamine (about 48 ℃ C.). Therefore, the reaction is carried out under pressure in order to be produced at a high temperature, which is disadvantageous for industrial production (see, WO 98/56802, example 8 (preparation 2), yield 11%). In addition, a catalyst needs to be used in the reaction. The applicant found that: the boiling point of the mixture of n-propylamine and isopropanol at atmospheric pressure is about 76 deg.C, resulting in a high yield (greater than 85%) of the reaction at a temperature of about 50-55 deg.C, without the need for a pressurized reactor or catalyst. Applicants' process provides high yields (85%) with higher purity than the products obtained by prior methods, and the free base form and acid salt of the compound of formula 1 are subjected to various crystallization methods, resulting in a high purity compound of formula 1, which purity can be used to formulate parenteral formulations.

In embodiment 2, the compound of formula 2 may be prepared as follows: the compound of formula 3 is treated with sulfur methide (sulfuryl methyl) at a temperature of about-80 to about-45 deg.C, and then the 2' -protecting group is removed by conventional methods to give the compound of formula 2. Preferably, the starting material for the process of embodiment 2 is a trifluoroacetic acid addition salt of the compound of formula 3,it is first converted into the free base form and then cooled to a low temperature of about-70 c and then reacted with a low temperature solution of methylene sulfide. Preferably, the methylenesulfide is dimethylmethylenesulfonium, e.g. (CH)₃)₂S⁺CH₂ ^-It can be prepared by conventional methods, for example: in an ether solvent such as THF or in CH₂Cl₂Trimethylsulfonium salts, such as (CH) phosphonium salts, DMF or DMSO or mixtures of two or more of the foregoing solvents are treated with an activating agent, such as potassium hydroxide, potassium tert-butoxide, sodium tert-butoxide, potassium ethoxide, sodium ethoxide, potassium hexamethyldisilazide (KHMDS) or sodium methoxide, with potassium tert-butoxide being preferred₃)₃SX, wherein X is halogen (preferably bromine) or sulfonate, more preferably trimethylsulfonium bromide. Removal of the protecting group in conventional manner, e.g. by catalytic hydrogenation, wherein R⁴Is CBZ.

In embodiment 3, the 4 "-ketone can be prepared in a continuous process in a single vessel. In the first step of the process, the 2' -hydroxy group is selectively protected in a conventional manner, preferably by treatment of R with benzyl chloroformate in dichloromethane⁴2' -hydroxy of the compound of formula 5 being hydrogen to give R⁴The compound of formula 4 being a benzyloxycarbonyl ("CBZ"). Preferably, at least 2 molar equivalents of benzyl chloroformate are employed in order to ensure that the 2' -hydroxyl group becomes fully protected. Dichloromethane is preferably used as solvent. Wherein the reaction is carried out in a volume of dichloromethane that is at least 15 times the volume of the starting material, thereby reducing the formation of bis-CBZ impurities. Wherein R is⁴The compound of formula 4, which is CBZ, can be isolated in the form of its dibenzoyl-D-tartrate salt, thus removing the potential bis-CBZ impurity. However, the water extraction treatment method of the compound of formula 4 is not preferred, and the isolated product is unstable due to the presence of benzylamine obtained by aminoalkylation of the compound of formula 4 with benzyl chloride (formed by decomposition of benzyl chloroformate). Thus, after the protecting step, the reaction mixture is preferably directly subjected to the second step without isolating the compound of formula 4. The second step, which may be carried out in the same vessel as the first step, comprises oxidation of the 4 "-hydroxyl groupTo the 4 "-keto group of the compound of formula 3. Preferably, the oxidation reaction is an oxidation of activated DMSO as described above, i.e. carried out at low temperature, for example at-60 to-70 ℃, which comprises carrying out the activation of DMSO in situ: trifluoroacetic anhydride was added to a cooled solution of the compound in DMSO, followed by triethylamine. The reaction mixture was then added to water and gradually warmed to room temperature. Preferably, the mixture is washed with water to give a solution of the compound of formula 3.

The trifluoroacetate salt of a compound of formula 3 can be prepared by: the reaction mixture of the oxidation step is washed with water, followed by the addition of trifluoroacetic acid and then a solvent suitable for salt crystallization, such as isopropanol or a mixture of dichloromethane and methyl tert-butyl ether ("MTBE"). Other acid addition salts, such as dibenzoyl-D-tartrate and phosphate, may also be prepared in conventional manner. The dibenzoyl-D-tartrate and phosphate salts are useful in the process of the invention, but are inferior compared to trifluoroacetic acid.

As shown in embodiment 4, in summary, the present invention relates to a two-stage process for preparing a compound of formula 1, wherein in the first stage, the compound of formula 3 is prepared by a single vessel process comprising: the compound of formula 5 is subjected to benzyloxycarbonyl protection of the 2' -hydroxy group to give the compound of formula 4, followed by direct oxidation of the 4 "-hydroxy group of the compound of formula 4 to give the ketone of the compound of formula 3, preferably isolated in the form of its trifluoroacetic acid addition salt; in a second stage, the free base of the compound of formula 3 (preferably prepared from its trifluoroacetate salt) is converted to the compound of formula 2 which is a4 "-epoxide, the 2 '-protecting group is removed and reduced to the 2' -hydroxy group, and the epoxide is opened with an amine in a mixture containing isopropanol to give the compound of formula 1.

Scheme 4

First stage and second stage

The compounds prepared by the process of the present invention are basic in nature and are capable of forming a wide variety of different salts with various inorganic and organic acids. Although these salts must be pharmaceutically acceptable for administration to mammals, it is often the case that the compound prepared by the process of the invention, in the form of a non-pharmaceutically acceptable salt, is isolated from the reaction mixture and then converted to the free base compound simply by treatment with an alkaline reagent for use in the subsequent reaction or for the preparation of a pharmaceutically acceptable acid addition salt. The base compounds prepared by the process of the present invention can be readily prepared as acid addition salts by treating the base compound with substantially equivalent amounts of the selected mineral or organic acid in an aqueous solvent medium or in a suitable organic solvent. After careful evaporation of the solvent, the desired solid salt is readily obtained. The desired salt may also be precipitated by adding a suitable mineral or organic acid to a solution of the free base in an organic solvent. The compounds of formula 1 and their pharmaceutically acceptable salts (hereinafter "active compounds") prepared by the process of the present invention may be administered orally, parenterally, topically or rectally for the treatment of bacterial or protozoal infections.

Generally, the optimal dose of active compound administered is from about 0.2 to about 200mg/kg body weight per day (mg/kg/day), given in single or multiple doses (i.e., 1 to 4 times per day), although the dosage will necessarily be adjusted depending on the chosen route of administration and the type, weight and health of the patient to be treated; however, it is most preferred to use dosage levels of from about 4 mg/kg/day to about 50 mg/kg/day. The dosage may be adjusted depending on the species of mammal, fish or bird being treated, the individual response of these animals to the drug, and the type of pharmaceutical formulation, time and interval of administration selected. In some instances, dosage levels below the lower limit of the aforesaid range may be higher than appropriate, while in other instances higher doses than the aforesaid range may be employed without any toxic or side effects, provided that such large doses are first divided into several small doses for administration throughout the day.

These active compounds may be administered alone or in combination with a pharmaceutically acceptable carrier or diluent by the routes described above, and such administration may be carried out in a single administration or in multiple administrations. More particularly, the active compounds may be administered in a variety of different dosage forms, i.e., they may be combined with various pharmaceutically acceptable carriers for administration in the form of tablets, capsules, lozenges, troches, hard candies, powders, sprays, creams, salves, suppositories, gels (gels), pastes, lotions, ointments, aqueous suspensions, injectable solutions, elixirs, and syrups. The carrier comprises solid diluent or filler, sterile aqueous medium, various non-toxic organic solvents and the like. Furthermore, oral pharmaceutical compositions may be suitably sweetened and/or flavored. Generally, in these dosage forms, the active compound is present in an amount of about 5.0% to about 70% by weight.

For oral administration, tablets containing various excipients such as microcrystalline cellulose, sodium citrate, calcium carbonate, dicalcium phosphate and glycine may be employed in combination with various disintegrants such as starch (preferably corn, potato or tapioca starch), alginic acid and certain complex silicates, together with granulation binders such as polyvinylpyrrolidone, sucrose, gelatin and acacia. Additionally, lubricating agents (e.g., magnesium stearate, sodium lauryl sulfate, and talc) are often useful for tableting. Solid compositions of a similar type may also be used as fillers in gelatin capsules; preferred materials in this regard also include lactose or milk sugar and high molecular weight polyethylene glycols. When aqueous suspensions and/or elixirs are desired for oral administration, the active compound may be combined with various sweetening or flavoring agents, coloring matter or dyes, and if desired, emulsifying and/or suspending agents in combination with diluents such as water, ethanol, propylene glycol, glycerin and various like combinations thereof.

For parenteral administration, solutions of the active compounds in sesame or peanut oil or aqueous propylene glycol may be employed. The aqueous solution may be suitably buffered if necessary and the liquid diluent first adjusted to an isotonic state. These aqueous solutions are suitable for intravenous injection. The oily solutions are suitable for intra-articular injection, intramuscular injection and subcutaneous injection. The preparation of all these sterile solutions is readily accomplished by standard pharmaceutical techniques known to those skilled in the art.

In addition, the compounds of the present invention may also be administered topically, in the form of creams, gels, pastes, patches, ointments and the like according to standard pharmaceutical practice.

For administration to animals other than humans, such as poultry or livestock, the active compounds can be administered in the form of animal feed or in the form of drench compositions.

The active compounds may also be administered in liposome delivery systems, for example in the form of small unilamellar vesicles (vesicles), large unilamellar vesicles or multilamellar vesicles. Liposomes can be prepared from a variety of phospholipids, for example, cholesterol, stearylamine or phosphatidylcholines.

The active compounds may also be coupled to soluble polymers such as targeted drug carriers. The polymer may include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamide phenyl, polyhydroxyethylaspartamide-phenol, or polyethyleneoxide-polylysine substituted with palmitoyl groups. Also, the active compound may be coupled to a class of biodegradable polymers for controlled release of drugs such as polylactic acid, polyglycolic acid, polylactic acid-polyglycolic acid copolymers, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydroxypyrans, polycyanoacrylates and cross-linked or amphiphilic block copolymers of hydrogels.

The following examples further illustrate the processes and intermediates of this invention, it being understood that: the invention is not limited to the specific details of the following examples.

Example 1

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -13- [ (2, 6-dideoxy-3-C-methyl-3-O-methyl-alpha-L-ribo-hexopyranosyl) oxy ] -2-ethyl-3, 4, 10-trihydroxy-3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) -2-O- [ (phenylmethoxy) carbonyl ] - -D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one

To a solution of 25kg (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -13- [ (2, 6-dideoxy-3-C-methyl-3-O-methyl- α -L-ribo-hexopyranosyl) oxy ] -2-ethyl-3, 4, 10-trihydroxy-3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) - β -D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecane-15-one in dichloromethane (425L) cooled to 0-5 ℃ was added 13.7kg of a solution of benzyl chloroformate in dichloromethane (25L), the dropping rate was controlled to maintain the temperature below 5 ℃. The resulting mixture was stirred at this temperature for 3 hours and then concentrated to 148L to give a dry solution containing about 26.6kg (90%) of the product (using HPLC-Waters Symmetry C8, 15 cm. times.3.9 mM I.D. column, 25mM potassium phosphate buffer (pH7.5) acetonitrile: methanol (35: 50: 15) as mobile phase, flow rate 2.0ml/min, electrochemical detection, retention time 8.2 minutes). This mixture was used directly in example 2.

Example 2

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -13- [ (2, 6-dideoxy-3-C-methyl-3-O-methyl- α -L-ribo-hexopyranosyl) oxy ] -2-ethyl-3, 4, 10-trihydroxy-3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) -2-O- [ (phenylmethoxy) carbonyl ] - β -D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one bistrifluoroacetate.

To the solution obtained in example 1 was added 58.6kg of dimethyl sulfoxide ("DMSO"), followed by cooling to-70 ℃. While maintaining the temperature of-70 to-60 ℃, 16kg of trifluoroacetic anhydride was added, the mixture was stirred for 30 minutes, then 17.2kg of triethylamine was added, and the resulting mixture was stirred for another 30 minutes. The reaction mixture was added to 175L of water, gradually warmed to room temperature, and the layers were separated. The organic layer was washed twice with 170L water and concentrated to about 100L. Then, 7.8kg of trifluoroacetic acid and then 236L of isopropanol were added and the mixture was concentrated to crystallize 29.5kg (87.9%) of product with a purity of 98% by HPLC.

Analyzing data: mp 187-192 deg.C

Elemental analysis (C)₄₉H₇₆F₆N₂O₁₈Calculated values: c, 53.74; h, 6.99; f, 10.41; n, 2.56; measured value: c, 53.87; h, 6.99; f, 10.12; and N, 2.59.

HPLC system: same as example 1; retention time was 9.5 minutes.

X-ray powder diffraction (d spacing): 6.3,8.3,8.8,9.4, 10.8, 11.8, 12.6, 13.0, 14.3, 15.4, 15.9, 16.4, 17.1, 17.4, 17.8, 18.1, 19.1, 19.8, 20.4, 21.1, 21.5, 21.7, 22.8, 23.4, 24.0.

Example 3

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -2-ethyl-3, 4, 10-trihydroxy-13- [ [ (3S, 4S, 6R, 8R) -8-methoxy-4, 8-dimethyl-1, 5-dioxaspiro [2.5] oct-6-yl ] oxy ]3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) -2-O- [ (phenylmethoxy) carbonyl ] -beta-D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one

(a) A solution of 109kg of the product from example 2 in 327L of dichloromethane was treated with a solution of 27.5kg of potassium carbonate in 327L of water. The layers were separated and the aqueous layer was washed with 327 liters of dichloromethane, the organic layers were combined, dried, evaporated to about 327L and cooled to-70 ℃.

(b) In a separate vessel, a suspension of 29.7g of trimethylsulfonium bromide in 436L of tetrahydrofuran ("THF") was evaporated to about 170L, cooled to-12 deg.C and treated with 36.8kg of potassium tert-butoxide at a temperature of-10 to-15 deg.C for 75 minutes. The mixture is then added to the dichloromethane solution of step (a) over a period of about 30 minutes while maintaining the temperature at-70 to-80 ℃, the resulting mixture is warmed to-65 ℃, and stirred for at least 1 hour. The mixture was then added to a solution of 55.4kg ammonium chloride in 469 liters of water. The mixture was stirred at 15-25 ℃ for 15 minutes, the layers were separated, the aqueous layer was washed with 360L dichloromethane, the organic layers were combined and evaporated to about 227L. To the resulting mixture was added 750L of acetone. The mixture was then evaporated to 227l, which solution contained about 70.1kg (80%) of the title product (HPLC-HPLC system: MetaSil AQ C18 column (from MetaChem, part number 0520-. This mixture was applied directly to example 4.

Example 4

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -2-ethyl-3, 4, 10-trihydroxy-13- [ [ (3S, 4S, 6R, 8R) -8-methoxy-4, 8-dimethyl-1, 5-dioxaspiro [2.5] oct-6-yl ] oxy ] -3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) -alpha-D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one

The solution containing the product of example 3 was mixed with 11kg of activated carbon, 17.5kg of 10% palladium-carbon (Johnson-Matthey type A402028-10) and 637L of acetone, and the resulting mixture was treated with hydrogen at 20-25 ℃ and 50psi pressure until the reaction was complete, and then filtered. The filtrate was concentrated to about 350L, then 1055L of water was added over 90 minutes. The crystalline product was collected by filtration, washed with a mixture of 132 l of water and 45 l of acetone and dried to yield 57.5kg (94.4%) of the title epoxide in the form of a monohydrate (water content determined by the Karl-Fischer method).

Analyzing data: HPLC system: as in example 3; retention time 13.3 min.

X-ray powder diffraction (d spacing): 6.0,8.5,9.4, 11.9, 12.7, 13.4, 15.2, 16.9, 17.5, 18.0, 18.9, 19.4, 19.9, 20.7, 21.2, 21.6, 22.8.

Example 5

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -13- [ (2, 6-dideoxy-3-C-methyl-3-O-methyl-4-C- [ (propylamino) methyl ] - α -L-ribo-hexopyranosyl) oxy-2-ethyl-3, 4, 10-trihydroxy-3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) - α -D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one bisphosphate

56kg of the epoxide monohydrate of example 4 were combined with 280L of isopropanol and 108.2kg of n-propylamine. The mixture was heated at 50-55 ℃ for 30 hours. Then concentrated in vacuo to about 112 l. To the concentrate was added 560L of ethanol and 44.8L of water. To this mixture was added dropwise over a period of about 2 hours 16.8kg of phosphoric acid in a solution of 252 liters of ethanol to crystallize the product. The resulting suspension was stirred for 18 hours, the mixture was filtered, the solid was washed with 28 liters of ethanol, and the product was dried to obtain 64.6kg (88%) of the title compound (HPLC-HPLC system: YMC-Pack Pro C18(YMC Inc. part # AS-12S03-1546WT) using 50mM dipotassium hydrogen phosphate buffer (pH 8.0): acetonitrile: methanol (61: 21: 18) AS a mobile phase at a flow rate of 1.0ml/min and an electrochemical detector. retention time of 26.4 minutes).

Example 6

Preparation of (2R, 3S, 4R, 5R, 8R, 10R, 11R, 12S, 13S, 14R) -13- [ (2, 6-dideoxy-3-C-methyl-3-O-methyl-4-C- [ (propylamino) methyl ] - α -L-ribo-hexopyranosyl) oxy-2-ethyl-3, 4, 10-trihydroxy-3, 5, 8, 10, 12, 14-hexamethyl-11- [ [3, 4, 6-trideoxy-3- (dimethylamino) - β -D-xylo-hexopyranosyl ] oxy ] -1-oxa-6-azacyclopentadecan-15-one free base

64.6kg of the product of example 5 were mixed with 433L of dichloromethane, 433L of water and 27.6kg of potassium carbonate, the mixture was stirred for 30 minutes, the organic layer was separated, and the aqueous layer was washed with 32L of dichloromethane. The combined organic layers were filtered to clarify and evaporated to about 155L. To the concentrate was added 386L heptane, the solution was evaporated to about 155L and cooled to 20-25 ℃ to give crystals. The mixture was stirred for 6 hours, the solid collected by filtration, washed with 110L of heptane and dried to yield 40.3kg (77%) of the title compound (HPLC; using the same system as in example 5; retention time 26.4 minutes).

Claims (15)

1. A process for the preparation of a compound of formula 3,

the process is prepared by oxidizing the C-4' hydroxyl group of the compound of formula 4,

wherein R is⁴Is a hydroxyl protecting group.

2. The process of claim 1, wherein the oxidation is carried out by: dimethyl sulfoxide is added to a solution containing the compound of formula 4 and a solvent, the mixture is cooled to about-70 ℃, dimethyl sulfoxide is activated in situ, and finally the reaction is terminated.

3. The process of claim 2, wherein the reaction temperature is maintained between-70 ℃ and-60 ℃ during the reaction until the reaction is terminated.

4. The method of claim 2, wherein the dimethylsulfoxide is activated with the following reagents: trifluoroacetic anhydride, oxalyl chloride containing trisilylacetamide, polyphosphoric acid, pyridine-SO₃Or acetic anhydride.

5. A process for preparing a trifluoroacetic acid addition salt of a compound of formula 3,

the method comprises the following steps: treating the compound of formula 3 with trifluoroacetic acid; crystallizing the acid addition salt thus obtained;

wherein R is⁴Is a hydroxyl protecting group.

6. The method of claim 5, wherein R⁴Is benzyloxycarbonyl.

7. The process of claim 5 wherein said acid addition salt is crystallized from isopropanol.

8. The process according to claim 5, wherein the acid addition salt is crystallized from a mixture of dichloromethane and methyl tert-butyl ether.

9. The method of claim 1, wherein the compound of formula 4 is prepared by protecting the 2' -hydroxy group of the compound of formula 5.

10. The process of claim 9 wherein the compound of formula 4 is not isolated and is directed to the oxidation step.

11. The process of claim 9 wherein the 2' -hydroxyl group is protected with a benzyloxycarbonyl group.

12. The method of claim 11, wherein the benzyloxycarbonyl protecting group is prepared by reacting at least 2 molar equivalents of benzyl chloroformate with a compound of formula 5.

13. A trifluoroacetic acid addition salt of a compound of formula 3,

wherein R is⁴Is benzyloxycarbonyl.

14. The salt of claim 13 having the structure of formula 3a

Wherein R is⁴Is benzyloxycarbonyl.

15. A dibenzoyl-D-tartrate salt of the compound of formula 3,

wherein R is⁴Is benzyloxycarbonyl.