Microwave Assisted Synthesis of N‐Substituted‐7‐hydroxy‐4‐methyl‐2‐oxoquinolines as Anticonvulsant Agents

The reaction of resorcinol with ethylacetoacetate yielded the 7‐hydroxy‐4‐methyl coumarin (1), which on treatment with benzidine gives 1‐(4ʹ‐amino‐biphenyl‐4‐yl)‐7‐hydroxy‐4‐methyl‐1 H ‐quinolin‐2‐one (2). 1‐{4ʹ‐[(Substituted benzylidene)‐amino]‐biphenyl‐4‐yl}‐7‐hydroxy‐4‐methyl‐1 H ‐quinolin‐2‐one (3a‐j) were obtained by reacting 1‐(4ʹ‐amino‐biphenyl‐4‐yl)‐7‐hydroxy‐4‐methyl‐1 H ‐quinolin‐2‐one (2) with different substituted aromatic aldehydes in presence of glacial acetic acid by microwave irradiation. The compound 1‐{4ɴ‐[(substituted benzylidene)‐amino]‐biphenyl‐4‐yl}‐7‐hydroxy‐4‐methyl‐1 H ‐quinolin‐2‐one (3a‐j) on cyclization with chloro acetyl chloride in presence of triethylamine as catalyst under microwave irradiation furnished 1‐{4ʹ‐[3‐chloro‐2‐(substituted phenyl)‐4‐oxo‐azetidin‐1‐yl]‐biphenyl‐4‐yl}‐7‐hydroxy‐4‐methyl‐1 H ‐quinolin‐2‐one (4a‐j). Purity of synthesized compounds was checked by TLC and the structures were elucidated by their IR, 1 H NMR, Mass and elemental analysis data. The synthesized compounds were screened for anticonvulsant activity.