Conversion Of Beta-Chloro-L-Alanine To Alpha-Carbobenzoxy-Dl-Diaminopropionic Acid

Several N-acyl-β-chloroalanine esters have been prepared from the ester which was obtained by chlorination of L-cystine diester. Reaction of benzoyl-β-chloro-L-alanine ethyl ester with potassium phthalimide followed by acid hydrolysis yielded DL-diaminopropionic acid. Reaction of carbobenzoxy-β-chloro-L-alanine ethyl ester with potassium phthalimide followed by saponification and mild acid hydrolysis yielded α-carbobenzoxy-DL-diaminopropionic acid. The racemization took place during the amination step.