AU2001221726A1 - Process for the preparation of 5- and/or 6-substituted-2- hydroxy-benzoic acid esters - Google Patents
Process for the preparation of 5- and/or 6-substituted-2- hydroxy-benzoic acid estersInfo
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- AU2001221726A1 AU2001221726A1 AU2001221726A AU2001221726A AU2001221726A1 AU 2001221726 A1 AU2001221726 A1 AU 2001221726A1 AU 2001221726 A AU2001221726 A AU 2001221726A AU 2001221726 A AU2001221726 A AU 2001221726A AU 2001221726 A1 AU2001221726 A1 AU 2001221726A1
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- 238000000034 method Methods 0.000 title claims description 29
- 230000008569 process Effects 0.000 title claims description 24
- 238000002360 preparation method Methods 0.000 title claims description 8
- -1 6-substituted-2- hydroxy-benzoic acid esters Chemical class 0.000 title description 8
- 150000001875 compounds Chemical class 0.000 claims description 19
- 239000002904 solvent Substances 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 16
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Natural products CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 10
- HTSGKJQDMSTCGS-UHFFFAOYSA-N 1,4-bis(4-chlorophenyl)-2-(4-methylphenyl)sulfonylbutane-1,4-dione Chemical compound C1=CC(C)=CC=C1S(=O)(=O)C(C(=O)C=1C=CC(Cl)=CC=1)CC(=O)C1=CC=C(Cl)C=C1 HTSGKJQDMSTCGS-UHFFFAOYSA-N 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- 125000000217 alkyl group Chemical group 0.000 claims description 5
- 150000001734 carboxylic acid salts Chemical class 0.000 claims description 5
- 125000004178 (C1-C4) alkyl group Chemical group 0.000 claims description 4
- 229910052736 halogen Inorganic materials 0.000 claims description 4
- 238000010992 reflux Methods 0.000 claims description 4
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical group [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 claims description 3
- 125000005843 halogen group Chemical group 0.000 claims description 3
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims description 2
- NLFBCYMMUAKCPC-KQQUZDAGSA-N ethyl (e)-3-[3-amino-2-cyano-1-[(e)-3-ethoxy-3-oxoprop-1-enyl]sulfanyl-3-oxoprop-1-enyl]sulfanylprop-2-enoate Chemical compound CCOC(=O)\C=C\SC(=C(C#N)C(N)=O)S\C=C\C(=O)OCC NLFBCYMMUAKCPC-KQQUZDAGSA-N 0.000 claims description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 2
- 239000001632 sodium acetate Substances 0.000 claims description 2
- 235000017281 sodium acetate Nutrition 0.000 claims description 2
- LMBFAGIMSUYTBN-MPZNNTNKSA-N teixobactin Chemical compound C([C@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CO)C(=O)N[C@H](CCC(N)=O)C(=O)N[C@H]([C@@H](C)CC)C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CO)C(=O)N[C@H]1C(N[C@@H](C)C(=O)N[C@@H](C[C@@H]2NC(=N)NC2)C(=O)N[C@H](C(=O)O[C@H]1C)[C@@H](C)CC)=O)NC)C1=CC=CC=C1 LMBFAGIMSUYTBN-MPZNNTNKSA-N 0.000 claims description 2
- 125000000218 acetic acid group Chemical group C(C)(=O)* 0.000 claims 1
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 claims 1
- 150000001299 aldehydes Chemical class 0.000 description 7
- 238000003786 synthesis reaction Methods 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000000047 product Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 239000012965 benzophenone Substances 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229930014626 natural product Natural products 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- 150000005166 2-hydroxybenzoic acids Chemical class 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000005481 NMR spectroscopy Methods 0.000 description 2
- RWCCWEUUXYIKHB-UHFFFAOYSA-N benzophenone Chemical compound C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 description 2
- 150000001735 carboxylic acids Chemical class 0.000 description 2
- 238000012777 commercial manufacturing Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000000417 fungicide Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- 239000000543 intermediate Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- DYLIWHYUXAJDOJ-OWOJBTEDSA-N (e)-4-(6-aminopurin-9-yl)but-2-en-1-ol Chemical compound NC1=NC=NC2=C1N=CN2C\C=C\CO DYLIWHYUXAJDOJ-OWOJBTEDSA-N 0.000 description 1
- 229910021592 Copper(II) chloride Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229940040526 anhydrous sodium acetate Drugs 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 150000008366 benzophenones Chemical class 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000013375 chromatographic separation Methods 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- MLUCVPSAIODCQM-NSCUHMNNSA-N crotonaldehyde Chemical compound C\C=C\C=O MLUCVPSAIODCQM-NSCUHMNNSA-N 0.000 description 1
- MLUCVPSAIODCQM-UHFFFAOYSA-N crotonaldehyde Natural products CC=CC=O MLUCVPSAIODCQM-UHFFFAOYSA-N 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- KWXBNUYCDMPLEQ-UHFFFAOYSA-N ethyl 2-hydroxy-6-methylbenzoate Chemical compound CCOC(=O)C1=C(C)C=CC=C1O KWXBNUYCDMPLEQ-UHFFFAOYSA-N 0.000 description 1
- VEUUMBGHMNQHGO-UHFFFAOYSA-N ethyl chloroacetate Chemical compound CCOC(=O)CCl VEUUMBGHMNQHGO-UHFFFAOYSA-N 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 230000000855 fungicidal effect Effects 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- FJKROLUGYXJWQN-UHFFFAOYSA-N papa-hydroxy-benzoic acid Natural products OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 235000011056 potassium acetate Nutrition 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000003586 protic polar solvent Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 229960004889 salicylic acid Drugs 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Description
Process for the preparation of 5- and/or 6 -substituted- 2 -hydroxybenzoic acid esters
Background of the invention
Derivatives of 2 -hydroxybenzoic acid esters are useful starting materials for natural product synthesis or for the manufacture of fungicidal benzophenones such ,.as those described in U.S. 5,773,663. Methods to prepare said 2 -hydroxybenzoic acid esters are known, i.e. F.M. Hauser et al., Synthesis, 1980, 814 or Y. Hamada, et al., Tetrahedron, Vol. 47 (1991), 8635. However, these known methods require several steps and utilize corrosive or toxic reagents and are not amenable to large scale preparation or commercial manufacturing conditions.
The two-step syntheses cited in Synthesis and Tetrahedron herein- above require the isolation of intermediates resulting in an undue solvent waste load on the environment. Further these synthe- ses require gaseous HC1 and a separate oxidation procedure employing oxidizing reagents such as Br2 or CuCl2.
Therefore, it is an object of this invention to provide an effective and efficient single-step process to prepare 5- and/or 6-substituted-2 -hydroxybenzoic acid esters which is amenable to large scale preparations and commercial manufacturing procedures .
It is another object of this invention to provide an effective means of obtaining a substituted-2 -hydroxybenzoic acid ester in good yield under relatively mild reaction conditions from readily available starting materials and reagents .
These and other objects and features of the invention will become more apparent from the. detailed description set forth herei - below.
Summary of the invention
The present invention provides a single-step process for the pre- paration of a compound of formula I
(I)
wherein R is Ci-Cg alkyl; and
R1 and R2 are each independently H or C1-C4 alkyl which process comprises reacting a compound of formula II
(II)
wherein R is Ci-Cg alkyl and X is halogen or 0C0CH3 with a compound of formula III
(III)
wherein R1 and R2 are each independently H or C1-C4 alkyl, and formula III compound is understood to be cis, trans, or a mixture thereof, in the presence of a C1-C4 carboxylic acid salt and a solvent, wherein the molar ratio of starting marterials: compound III to compound II is higher or equal to 1.8.
Detailed description of the invention
Substituted-2 -hydroxybenzoic acid esters of formula I are useful as key starting materials in natural product synthesis and in the manufacture of important benzophenone fungicidal agents. Therefore, the efficient preparation of such fungicidally active compounds in an environmentally sound manner is highly desirable.
The present single-step process makes salicylic acid of the formula I available from β-ketoesters of the formula II and aldehydes of the formula III. Its practicability is ensured by using the aldehyde III in a molar ratio of not less than 1.8 relative to the compound II. This ensures that the reaction mixture remains efficiently stirrable even at low solvent quantities and consistently good yields are obtainable even on an industrial scale.
In a preferred embodiment of the process, the aldehyde III is initially charged and subsequently the salt and the solvent are added in succession or concurrently in the course of generally 0 to 3 hours.
It can further be of advantage to raise the reaction temperature in the course of the reaction from initially 60-120°C to finally 130-140°C.
Preferred compounds prepared by the process of the invention are those compounds of formula I wherein R1 is C1-C4 alkyl and R2 is hydrogen. More preferred compounds are those compounds of formula I wherein R1 is methyl and R2 is hydrogen.
Preferred compounds of formula II employed in the process of the invention are those compounds wherein X is halogen. More preferred compounds are those compounds of formula II wherein X is Cl .
Compounds of formula III may be represented in the σis or trans configuration or as a mixture thereof. In the specification and claims, compounds designated as formula III include the cis iso- er, the trans isomer or a mixture thereof.
The term halogen as used in the specification and claims designa- tes Cl, Br, F or I.
In accordance with the process of the invention, a β-ketoester of formula II is reacted with an α,β-unsaturated aldehyde of formula III in the presence of a C1-C4 carboxylic acid salt and a solvent to form the desired product of formula I. The reaction is shown in flow diagram I wherein M is an alkali metal or an alkaline- earth metal.
Flow diagram I
Suitable solvents for use in the inventive process include polar solvents, preferably protic solvents such as C1-C4 carboxylic acids or C1-C.6 alkanols. Preferred solvents are C2-C4 carboxylic acids or mixtures of a C2-C4 carboxylic acid and a Ci-Cg alkanol, more preferably acetic acid or a mixture thereof with methanol or ethanol. In general, more than 2.5 molar equivalents of solvent; preferably about 2.5 to 5 and more preferably about 2.5 to 3.5 molar equivalents of solvent were used.
Acid salts suitable for use in the process of the invention are C1-C4 carboxylic acid alkali metal or alkaline-earth salts, more preferably acetic acid alkali metal salts such as sodium acetate or potassium acetate. Preferably about 1.3 to 3.0 molar equivalents, more preferably about 1.4 to 1.6 molar equivalents of the carboxylic acid salt were added to the reaction mixture.
In the present process, the aldehyde III is used in a molar ratio of not less than 1.8 relative to the compound II. Preferably about 1.9 to 2.5 and more preferably about 2.0 to 2.2 molar equiva- lents of aldehyde III were reacted.
In a preferred embodiment of the process, the aldehyde III is initially charged and subsequently the salt and the solvent are added in succession or concurrently in the course of generally 0 to 3 hours. It can be of advantage here first to add a portion or the total amount of the salt and only then to start with the addition of the solvent. Compound II is generally added last in the course of 0 to 3 hours .
In the process of the invention, reaction rate is directly related to reaction temperature, that is, the reaction rate increases with increased temperature. However, excessively high reaction temperatures may lead to decomposition and the formation of unde- sired by-products, thereby reducing product yield and purity. Suitable reaction temperatures in the process of the invention may range from room temperature to the reflux temperature of the solvent preferably about 60°C to 150°C, more preferably about 110°C to 140°C.
It can further be of advantage to raise the reaction temperature in the course of the reaction from initially 60-120°C to finally 130-140°C. The reaction temperature can be raised for example by removing low boilers, if necessary by applying reduced pressure. It is similarly possible to carry out the reaction in a closed system. In this case, a higher reaction temperature will automa-
tically result in a higher pressure. The pressure employed is preferably in the range from 0.1 to 6 at .
The individual reactants are generally added at room temperature to the reflux temperature of the solvent.
The reaction time is generally in the range from 3 to 8 hours.
The formula I hydroxybenzoic acid ester product may be isolated using conventional isolation techniques such as precipitation, decantation, filtration, extraction, chromatographic separation or the like, preferably filtration or extraction.
Compounds of formula I are useful as intermediates in the synthe- sis of natural products and in the manufacture of benzophenone fungicidal agents as described in U.S. 5,773,663.
For a more clear understanding of the invention, the following example is set forth below. This example is merely illustrative and is not be understood as limiting the scope or underlying principles of the invention in any way.
The term NMR designates nuclear magnetic resonance spectroscopy. Unless otherwise mentioned, all parts are parts by weight.
Example 1
Preparation of Ethyl 2-hydroxy-6-methylbenzoate
A 4 1 jacketed vessel fitted with a destination apparatus was initially charged with 770.9 g [11 mol] of crotonaldehyde. With stirring, 615.2 g [7.5 mol] of anhydrous sodium acetate were added and the batch was heated to 60°C. 900 g of acetic acid were then metered in over an hour, during which the temperature rose to 83°C. The suspension was then heated under reflux and admixed with 857.2 g [5 mol] of ethyl 2-chloroacetate (purity: 96%) in the course of an hour.
The batch was subsequently stirred for five hours, during which initially about 700 ml of low boilers were destilled off until an internal temperature of 130°C was attained. The pressure was then reduced to 200 mbar and the distallation continued until the in-
ternal temperature again reached 135°C.
The residue was cooled down to 85°C and admixed with 1250 g of water (preheated to 80°C) . After 10 min of stirring at 80°C the aqueous phase was separated off. This afforded 893 g of organic phase as a dark brown oil having a product content of 63.2% (which corresponds to a yield of 62.6% of theory) .
Claims (1)
- I claim:1 . A process for the preparation of a compound of formula I(I)wherein R is Cχ -Cg alkyl ; andR1 and R2 are each independently H or C1 -C4 alkyl which pro cess comprises reacting a compound of formula II(IDwherein R is Ci-Cg alkyl and X is halogen or OCOCH3 with a compound of formula III(III)wherein R1 and R2 are each independently H or C1-C4 alkyl, in the presence of a C1-C4 carboxylic acid salt and a solvent, wherein the molar ratio of compound III : compound II is higher or equal to 1.8.The process according to claim 1 wherein the aldehyde III is initially charged, the salt and the solvent are subsequently added in succession or concurrently and finally compound II is added.3. The process according to claim 1 wherein a reaction temperature of initially 60°C to the reflux temperature of the solvent used is set and the temperature is raised to 130-140°c in the course of the reaction.4. The process according to claim 1 wherein the solvent is a C1-C4 carboxylic acid or a mixture thereof with a Ci-Cg alka- nol.5. The process according to claim 2 wherein the solvent is acetic acid and the C1-C4 carboxylic acid salt is sodium acetate.6. The process according to claim 1 having a formula II compound wherein X is Cl.7. Th.e process according to claim 1 having a formula III compound wherein R1 is methyl and R2 is H.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2000/013259 WO2002051790A1 (en) | 2000-12-23 | 2000-12-23 | Process for the preparation of 5- and/or 6 - substituted - 2 - hydroxy-benzoic acid esters |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| AU2001221726A1 true AU2001221726A1 (en) | 2003-01-23 |
| AU2001221726B2 AU2001221726B2 (en) | 2007-09-06 |
| AU2001221726B8 AU2001221726B8 (en) | 2007-09-27 |
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