Unexpected Reactivity of N-Acyl-Benzotriazoles with Aromatic Amines in Acidic Medium (ABAA Reaction)

Abstract

Despite the large number of methods for the synthesis of amides, formation of the amide bond from aromatic amines has always been a challenge for organic chemists due to their weak nucleophile character. We describe here a new efficient method of amide formation from N-Acyl-Benzotriazoles and Aromatic Amines (ABAA reaction) including aniline derivatives, in acidic conditions. This reaction is selective for aromatic amines, since aliphatic amines did not react under the same experimental conditions. Using the ABAA reaction, we have synthesized a series of aromatic amide compounds including labelled enzyme substrates, in excellent yield. The ABAA reaction also allowed the one-pot synthesis of Nordiazepam, which is a precursor of the anxiolytic Diazepam (Valium®). This procedure opens new ways of synthesis of amides from aromatic amines, as well as of heterocyclic structures.