Process for the preparation of 1-[3-mercapto-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid
US4332725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1980 |
| Grant date | Jun 1, 1982 |
| Priority date | — |
| Expiry date | Dec 22, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C53/50
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a novel process for the preparation of 1-[3-mercapto-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid through the N-acylation of L-proline. According to the process of the invention L-proline is acylated with a 3-halogen-2-methylpropionyl chloride of the formula III ##STR1## wherein Hal is a halogen atom, preferably chlorine or bromine, the obtained 1-[3-halogen-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid, wherein Hal is as stated above, is reacted with an alkali thiosulfate or alkali trithiocarbonate and the reaction product is hydrolized with an acid. The process of the invention is very economical as compared with the known processes. The desired product is prepared from methacrylic acid in 4 reaction steps with a total yield of 25 percent and from L-proline in 2 reaction steps with a total yield of 30 percent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.