Synthesis of 2-Substituted Benzimidazoles and 1,5- Disubstituted Benzodiazepines Using Alum

Abstract

Alum, have been investigated for their catalytic activity in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesizes 2-substituted benzimidazole and 1,5-disubstituted benzodiazepines respectively. The isolated yields of 2-substituted benzimidazole and 1,5-disubstituted benzodiazepines are in the range of 30% to 95%. This method has been found to be simple and economical. The solid supports could be regenerated and reused without much loss in their activity. Further, the solid supports have been also found to be effective as general catalysts in the condensation of o-phenylenediamine with other substituted aldehydes and ketones.