PRODUCTION OF alpha-L-ASPARTYL-L-PHENYLALANINE ALKYL ESTERS

摘要

1,243,169. a - L - Aspartyl - L - phenylalanine alkyl esters. AJINOMOTO CO. Inc. 20 April, 1970 [30 April, 1969], No. 18849/70. Heading C2C. An a-L-aspartyl-L-phenylalanine alkyl ester of the formula wherein R is a (C 1- C 4 ) alkyl group and Ph is an optionally substituted phenyl group, is obtained by reacting an N-protected-L-aspartic anhydride having its N atom protected by a formyl, carbobenzoxy orp-methoxycarbobenzoxy group with an L-phenylalanine (C 1- C 4 ) alkyl ester in an organic solvent to form an N-protected a-L- aspartyl-L-phenylalanine (C 1- C 4 ) alkyl ester and an N-protected (#-L-aspartyl-L-phenylalanine (C 1- C 4 ) alkyl ester, and either (a) separating the N-protected #-L-aspartyl-compound and eliminating the protecting groups from the N-protectedα-L-aspartyl-compouhd to obtain the desired ester; or (b) eliminating the protecting groups from the N-protected a- L-aspartyl compound and the N-protected #.L-aspartyl compound and separating the # - L - aspartyl - L - phenylalanine (C 1- C 4 ) alkyl ester from the unprotected a- and #-L- aspartyl - L - phehylalahihe (C 1- C 4 ) alkyl esters formed to obtain the desired ester. The N - protected a - and # - L aspartyl - L- phenylalanine .(C 1 -C 4 ) alkyl esters may be separated by converting them to their correspending amine salts followed by fractional crystallization. The unprotected a- and #-L- aspartyl - L - phenylalanine (C 1- C 4 ) alkyl esters may be separated by fractional crystallization. Examples are given which illustrate the process.