1, 5-Benzodiazepines have been investigated extensively by organic chemists due to their medicinal and pharmacological properties. These compounds are synthesized by condensation of o-phenylenediamines with carbonyl compounds in the presence of acid catalysts. Objectives: During our studies on the application of silica resin with acid functional moieties, we found that SiO 2 /H 2 SO 4 mixture is a simple and efficient catalyst for this method under microwave irradiation. Materials and Methods:

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... he reaction was carried out simply by grinding SiO 2 /H 2 SO 4 mixture with o-phenylenediamine, and ketone in the mortar; then the mixture was poured 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 conversion to form corresponding 1, 5-benzodiazepines. Conclusions: In conclusion, this method is a simple, rapid, and high yielding reaction (78-95%).