PROCESS FOR THE PREPARATION OF LOWER ALKYL ESTERS OF N-L-.alpha.-ASPARTYL-L-PHENYLALANINE AND OF NEW INTERMEDIATES FOR THE PREPARATION THEREOF

摘要

ABSTRACT OF THE DISCLOSUREThe invention relates to a selective process for thepreparation of N-L-.alpha.-aspartyl-L-phenylalanine-1-lower alkylester which comprises:A. reacting an L-aspartic acid 4-arylmethyl ester with ai) 1,3-diketone; orii) acylacetic ester;in the presence of a base to form the salt ofi') L-N-(1-alkyl-2-acyl-vinyl)-aspartic acid4-arylmethyl ester; orii') L-N-(1-alkyl-2 alkoxycarbonyl-vinyl)-asparticacid 4-arylmethyl ester,and then either:1) reacting salt (i') or (ii') with an organic or in-organic acid halide having the formula X-A, whereinX represents a halogen and A has the meaning indicatedhereinafter, or with an acid anhydride to form IwhereinR represents an alkyl radical with 1 to 6 carbonatoms;R' represents an alkyl or alkoxy radical with 1 to6 carbon atoms;Ar represents the phenyl, nitrophenyl, halogenphenylor alkylphenyl radical; and