Two series of new pirfenidone derivatives, in which phenyl groups or benzyl groups are attached to the nitrogen atom of the pyridin-2(1H)-one moiety were synthesized and evaluated as anti-fibrosis agents. Among them, compound 5d, with a (S)-2-(dimethylamino) propanamido group in the R2 position (series 1) exhibited 10 times the anti-fibrosis activity (IC50: 0.245 mM) of pirfenidone (IC50: 2.75 mM). Compound 9d (series 2) gave an IC50 of 0.035 mM against the human fibroblast cell line HFL1. The mechanism of the optimal compound inhibiting fibrosis was also studied.
