SiO2/H2SO4: An Efficient Catalytic System for Solvent-free 1, 5-benzodiazepinesSynthesis

1, 5-benzodiazepines have been investigated extensively by organic chemistsdue to their medicinal and pharmacological properties. these compounds are synthesizedby condensation of o-phenylenediamines with carbonyl compounds in thepresence of acid catalysts.objectives: during our studies on the application of silica resin with acid functionalmoieties, we found that sio2/h2so4 mixture is a simple and efficient catalyst for thismethod under microwave irradiation.materials and methods: the reaction was carried out simply by grinding sio2/h2so4mixture with o-phenylenediamine, and ketone in the mortar; then the mixture waspoured out into a sealed flask. subsequently, it was irradiated in a microwave oven.results: in this method a series of cyclic and acyclic ketones underwent above conversionto form corresponding 1, 5-benzodiazepines.conclusions: in conclusion, this method is a simple, rapid, and high yielding reaction(78–95%).