PRODUCTION OF N-ACYLPHENYLALANINES

摘要

An N-acyl-substituted or unsubstituted phenylalanine is prepared by hydrolyzing a 2-substituted-4-substituted or unsubstituted benzylidene-5-oxazolone with an alkali, adjusting the reaction system containing its hydrolysis product with acid to a pH of 5 - 9 and reducing the resultant reaction solution catalytically in the presence of a palladium or platinum reducing catalyst. The reduction is carried out continuously without isolating the alkaline hydrolysis product, i.e., a substituted or unsubstituted N-acylaminocinnamic acid from the reaction system. …The catalyst can be recovered after completion of the reduction and used repeatedly without additional treatment and without any observed lowering in its catalytic activity. Accordingly, the reductions using the recovered catalyst may proceed at pratically the same rate as reductions using a fresh catalyst.