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

A new approach has been successfully employed to synthesize cyclic ureas via carbonylation, utilizing Boc anhydride and employing K 2 CO 3 as a base along with N , N -dimethylformamide as the solvent. Remarkably high yields were achieved using K 2 CO 3 in conjunction with (Boc) 2 O, 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, 1 H NMR, and 13 C NMR.