Preparation and antiinflammatory activity of 2- and 4-pyridones.

Several N-alkyl- and N-arylacetoacetamides have been self-condensed to form pyridones. N-Alkylacetoacetamides give 2-pyridones, while N-arylacetoacetamides give 4-pyridones. In an attempt to develop nonacidic, nonsteroidal antiinflammatory agents, the pyridones were tested in a carrageenan-induced pedal edema assay in rats. While the 2-pyridones were not active, 9 of 17 4-pyridones tested were active, and one compound (4g) had antiinflammatory efficacy in a dose-response assay (ED50 values). Most compounds were considered nontoxic by determination of approximate LD50 values in mice by a standard multidimensional observational assay.