An Improved Synthesis of Urea Derivatives from N-Acylbenzotriazole via Curtius Rearrangement

Abstract

The good leaving tendency of the benzotriazole moiety has been exploited for the synthesis of symmetric, unsymmetric, N-acyl, and cyclic ureas in good yields from N-acylbenzotriazoles by treating the latter with various amines in the presence of TMSN3/Et3N in a sealed tube. The salient features of the devised protocol includes the high-yield, mild, metal-free, one-pot reaction conditions, and short reaction time. Furthermore, in many cases, no column chromatography is required for the purification.