Conversion of penicillins into biosynthetically significant peptides
Abstract
Mild acid treatment of the 4-mercapto-azetidin-2-one (1) gave the thioaldehyde (2) which was intercepted by reduction to the peptide (5), prior to enolization; a similar sequence with the dihydro-derivative (11) provided the cysteinyl-valine peptide (7), which represents a formal reversion of penicillin biosynthesis.