A new synthetic approach to cyclic ureas through carbonylation using di-tert-butyl dicarbonate (boc anhydride) via one pot strategy

Abstract

A new approach has been successfully employed to synthesize cyclic ureas via carbonylation, utilizing Boc anhydride and employing K₂CO₃ as a base along with N,N-dimethylformamide as the solvent. Remarkably high yields were achieved using K₂CO₃ in conjunction with (Boc)₂O, enabling the streamlined preparation of benzimidazolones and 2-benzoxazolones within a single reaction vessel. Significantly, this approach obviates the necessity for using any dangerous reagents, rendering it environmentally friendly, and its key benefit lies in being a metal-free system. The method stands out for its efficiency, concise pathway, optimization from readily accessible starting materials, and ease of execution. The resulting benzimidazolones and 2-benzoxazolones were thoroughly characterized using techniques including LCMS, ¹H NMR, and ¹³C NMR.