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.
[Full Text Article]