An efficient synthesis of some new 3-bipyridinyl substituted coumarins as potent antimicrobial agents

As a part of the ongoing studies in developing new antimicrobials, a series of structurally novel 3-bipyridinyl substituted coumarin derivatives 4a-f and 5a-f were synthesized by a single-step reaction protocol under Krohnke's reaction conditions. 1H NMR, 13C NMR, IR and mass spectral techniques were employed for the structural elucidation of the synthesized compounds. An evaluation of antimicrobial activity showed that almost all compounds exhibited better results than the referenced drugs. Among the synthesized derivatives 4f, 5a and 5d were found to be the most potent analogs. Thus they could be promising lead for novel drugs.