Novel pirfenidone analogs as antifibrotic agents: Synthesis and antifibrotic evaluation of 2-pyridones and fused pyridones

A new series of substituted 1-(2-ethylphenyl)-2-oxo-1,2-dihydropyridine-3-carbonitriles have been synthesized. Moreover, substituted bicyclic derivatives e.g. thieno[3,4-c]pyridone, pyrido[3,4-c]pyridone, benzo[c]pyridone and tricyclic derivatives, chromeno[3,4-c]pyridones have been prepared and evaluated for their antifibrotic activity. Among the tested compounds, compounds 4d and 5a exhibited potent antifibrotic activity without harmful side effects on liver and kidney functions. Detailed synthesis, spectroscopic and biological data are reported.