Benzimidazoles synthesis in the presence of nano silica chloride as a solid acid catalyst under ultrasound and microwave irradiation conditions

چکیده مقاله

Benzimidazoles are conveniently synthesized by the reaction of o-phenylenediamine with acids or aldehydes.1,2 Benzimidazole derivatives are widely found in commercial and experimental drugs condidates. Therefore, it is not surprising that the efficient construction of benzimidazole core become one of the most exciting topics for organic and medicinal chemists.3 It is observed that under microwave and ultrasound irradiation not only the reaction times are reduced but also the yields are increased. Microwave and ultrasound techniques as very efficient and eco-friendly alternative to traditional for introducing energy in organic reaction has substantially been increased.4 In this study, new methods have been introduced for the preparation of 2-substituted benzimidazoles in the presence of nano silica chloride as an efficient catalyst and atmospheric air as an oxidant under ultrasound and microwave irradiation conditions.