robust approach leading to novel densely functionalized four-cyclic benzo[e]pyrazolo[5′,1′:2,3]pyrimido[4,5-b][1,4]diazepines with antibacterial activity toward resistant strains

A straightforward approach for the regioselective synthesis of various derivatives of benzo[e]pyrazolo[5′,1′:2,3]pyrimido[4,5-b] [1, 4] diazepine as a novel heterocyclic system from the annulation of 6-bromo-7-chloro-3-cyano-2-(ethylthio)-5-methylpyrazolo[1,5-a]pyrimidine with several 2-amino-n-substituted benzamides as bident nucleophiles in the presence of k2co3 and dmf has been disclosed. the right regioisomer was elucidated by 2d-noesy nmr spectroscopy, as well. most of the novel synthetic compounds exhibited antimicrobial activity though relatively at high concentrations against multi-drug-resistant klebsiella pneumoniae and escherichia coli clinical isolates possessed of strong biofilm formation ability. n-cyclohexyl-substituted pyrazolopyrimidobenzodiazepine (3 h) as the most potent compound represented 100% growth inhibitory on both types of bacterial strains, which brings promises for further changes to develop potential antimicrobial drugs.