Novel,efficient,and green procedure for the synthesis of 1,5-benzodiazepines catalyzed by MgBr_2 in aqueous media

MgBr2 performs as a novel catalyst for the synthesis of various 1,5-benzodiazepine derivatives from wide range of substituted o-phenylenediamines and various ketones in good to excellent isolated yields (93-98%) using water as solvent at ambient temperature. Several solvents were examined for this reaction; however, in terms of reaction yield and time, water was found to be the optimum solvent. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster (40-60 min) reactions and good to excellent yields of products.