Acylaminoacetyl derivatives of active methylene compounds. 1. The cyclization of the benzoylaminoacetyl derivatives to α-substituted tetramic acids

Hippuric acid was converted to α-Y-substituted tetramic acids (Y = -CN, -CO₂R and -COCH₃) according to the following general scheme of reactions: a) preparation of the hippuric acid chloride or of its p-nitrophenyl ester; b) C-acylation of an active methylene compound Y-CH₂-CO₂R using the acid chloride or the active ester; and c) intramolecular condensation of the C-acylation compound to an α-Y-substituted tetramic acid. The conditions of the C-acylation reaction and the structure and reactivity of the benzoylaminoacetyl derivatives were investigated.