title: SiO2/H2SO4: An Efficient Catalytic System for Solvent-free 1, 5-benzodiazepines Synthesis.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  During our studies on the application of silica resin with acid functional moieties, we found that SiO2/H2SO4 mixture is a simple and efficient catalyst for this method under microwave irradiation.
  
  
  METHODS
  The reaction was carried out simply by grinding SiO2/H2SO4 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%).
authors.affiliation: Research Center of Marine Pharmaceutical Science, Ahvaz Jundishapour University of Medical Science, Ahvaz, IR Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Shushizadeh
authors.affiliation: Ahvaz Jundishapour University of Medical Sciences, Science and Research Branch- Khoozestan, Ahvaz, IR Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Dalband
keywords: 1,2-diaminobenzene, Microwave; Ketones; Radiotherapy; Sulfuric acid