The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1982
Filed:
Dec. 22, 1980
Janos Fischer, Budapest, HU;
Laszlo Rozsa, Budapest, HU;
Pal Vago, Budapest, HU;
Anna Bakonyi, Budapest, HU;
Gabor Fazekas, Budapest, HU;
Egyt Gyogyszervegyeszeti Gyar, Budapest, HU;
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.