Synthesis and anti-inflammatory activity of N-substituted 2-oxo-2H-1-benzopyran-3-carboxamides and their 2-iminoanalogues.

Aseries of N-arylsubstituted 2-imino-2H-1-benzopyran-3-carboxamides 3a and b and 2-oxo-2H-1-benzopyran-3-carboxamides 4a-h were synthesized and evaluated for their anti-inflammatory activity in carrageenan-induced rat paw oedema assays and in acetic acid-induced peritonitis tests in albino rats. The resulting products were found to be active anti-inflammatory agents and their effects were comparable to that of piroxicam as the reference compound. In the consideration of the efficacy of the compounds in these assays, 2-imino/oxo-2H-1-benzopyran-3-carboxamides 3a and b and 4a-h were further studied at graded doses for their acute toxicity (ALD(50)) in albino mice and were essentially non-toxic at the highest dose tested.