Activation of the Carboxylic Acids by Anhydride Formation with N-Acyl-N-Alkyl Carbamic Acid

Abstract

The mixed anhydrides with N-acyl carbamic acid (IV) were prepared by the reaction of carboxylic acids (Ill) with N-chlorocarbonyl lactams (Ila) or sec. amides (lib). Decarboxylation of IV yielded N-acyl lactams (VI), while symmetrical anhydrides (VII) were obtained by the side reaction of IV with carboxylic acids (III). Aminolysis of IV yielded carboxylic acid amides (IX) in high yield and purity. IVb was used in the preparation of aminosubstituted beta-lactam antibiotics (XII), as a new way of activating N-protected phenylglycine (lllg), during acylation of 6-APA or 7-ADCA (XI)