Process for the preparation of substituted carboxylic esters
US7153675B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2002 |
| Grant date | Dec 26, 2006 |
| Priority date | — |
| Expiry date | Apr 6, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC12P41/005
- WIPO fieldBiotechnology
- WIPO sectorChemistry
Abstract
A process for the preparation of 2(S)-alkyl-5-halogenpent-4-ene carboxylic esters by enzymatic hydrolysis, comprising the steps: a) enzymatic hydrolysis of racemic 2-alkyl-5-halogenpent-4-ene carboxylic esters in aqueous and alkaline medium in the presence of an esterase; b) isolation of 2(S)alkyl-5-halogenpent-4-ene carboxylic esters by extraction with an organic solvent; c) isolation of 2(R)-alkyl-5-halogenpent-4-ene carboxylic acids from the aqueous-alkaline medium; d) Esterification of 2(R)-alkyl-5-halogenpent-4-ene carboxylic acids, e) subsequent racemization to form 2-alkyl-5-halogenpent-4-ene carboxylic esters; and f) return of the racemate obtained in step e) to step a), if necessary together with fresh racemic 2-alkyl-5-halogenpent-4-ene carboxylic esters. The process permits the undesired R-stereoisomers to be converted into the desired 2(S)-alkyl-5-halogenpent-4-ene carboxylic esters to avoid waste product from the synthesis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.