Propionic acid derivatives

摘要

The (S)-3-alkanoylthio- and benzoylthio-2-methylpropionic acids of the formula <IMAGE> in which R1 denotes alkyl or phenyl, and their reactive functional derivatives are useful intermediates in the synthesis of chiral compounds, in particular of the known antihypertensive 1-[(S)-3-mercapto-2-methylpropanoyl]-L-proline and of its analogues. The compounds of the formula I and their reactive functional derivatives and salts thereof are prepared by resolution of the corresponding racemic acids by means of cinchonidine and if necessary conversion into a reactive functional derivative or a salt.