A new method for the synthesis of α‐esters of N‐acylglutamic acids

N‐Benzyloxycarbonyl‐, N‐tosyl‐ and N‐phthaloylglutamic acids have been converted into various α‐esters by addition of an equimolecular amount of a base triethylamine or dicyclohexylamine) and treatment with an appropriate alkyl halide or dialkyl sulphate. The esters were isolated as dicyclohexylammonium salts and appeared free of the corresponding γ‐esters after one crystallization (Table I). The method surpasses older procedures by its symplicity and higher yield, but fails for the synthesis of p‐nitrophenyl or tert.butyl esters. The α‐esters of corresponding aspartic acid derivatives are not obtained in this way.