Abstract

NOVEL SYNTHESIS OF 2-SUBSTITUTED BENZIMIDAZOLE BY RING CONTRACTION REARRANGEMENT OF 1, 5- BENZODIAZEPINES

Tchambaga Etienne Camara, Siomenan Coulibali*, Soleymane Kone, Timotou Adeyole,
Ane Adjou

Abstract

The interaction of aromatic ketones with aldehydes allowed accessing α, β-unsaturated ketones (chalcones) 9. Subsequently, these chalcones 9 were reacted with orthophenylenediamine to give the corresponding 1H-1, 5-benzodiazepines 11. Treatments of benzodiazepine under basic or acid condition give respectively 2-substituted benzimidazole 12 or 14 via Ring Contraction Rearrangement. All compounds were characterized by means of 1H, 13C NMR and mass spectroscopy. To explain the formation of benzimidazole, we have made theoretical calculations.

Keywords: Benzimidazole, chalcones, benzodiazepines, orthophenylenediamine.