Synthesis of some novel 2,4-disubstituted-1,5-benzodiazepine derivatives under solvent – free microwave irradiation conditions and their antimicrobial evaluation

A new series of 2,4-disubstituted-2,3-dihydro substituted-1,5-benzodiazepine derivatives (3a-g) were synthesized by the condensation of o-phenylene diamine and various 1-(4’-substituted phenyl)-3-(3 mono-, or 4 mono-, or 3,4 di-, or 3,4,5 tri-substituted phenyl)-2-propene-1-one under microwave irradiation conditions. All the reported reactions were also pursued via conventional method for a comparative study. The results obtained confirm the superiority of the microwave irradiation method over the classical reflux heating. Newly synthesized compounds were characterized on the basis of elemental analysis and spectral studies viz. IR, 1H NMR, 13C NMR, mass. All the compounds were screened for their in vitro activities against Gram-positive, Gram-negative bacteria and fungal strains. They exhibited mild to moderate antimicrobial activity.