Inter‐ und intramolekulare Acylwanderungen an 1(9)H‐2,3‐Dihydro‐imidazo[1,2‐a]benzimidazolen

Abstract

Inter‐ and Intramolecular Acyl Transfer on 1(9)H‐Imidazo[1,2‐a]benzimidazolesThe new imidazo[1,2‐a]benzimidazoles (3) react with electrophiles like aroyl chlorides, isocyanates, cyanates, chloroformates and chlorothioformates to give the 9‐acyl derivatives (4a–1).At higher temperatures intermolecular acyl transfer takes place to give the l‐acyl compounds (5a–m). In the case of 1‐carbamoyl imidazo[1,2‐a]benzimidazoles (5) was observed intramolecular acyl transfer in the presence of strong bases and 1‐benzimidazol‐2‐yl‐hydantoins (6) were isolated.The structures of the prepared compounds could be inferred from their 1H and 13C n.m.r., mass spectra and were corroborated by the comparison with the data of similar derivatives as well as by chemical means.