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A series of 2'-substituted chalcone derivatives has been found to show potent inhibition of the production of IL-1 beta from human peripheral blood monocytes stimulated with lipopolysaccharide (LPS), with IC50 values in the 0.2-5.0-microM range. Some members of the series have also shown inhibition of septic shock induced in mice by injection of LPS, although with low potency. Qualitative structure-activity relationships have shown that the enone is required for activity, which may be mediated by conjugate addition of a biological nucleophile to the chalcone. Electron-poor aromatic rings beta to the ketone give enhanced potency. Although electronic effects in the other ring (directly attached to the ketone) are minimal, this ring must possess an ortho substituent for good activity without cytotoxicity, suggesting a degree of selectivity which would not be expected for simple, nonspecific alkylating agents.

Nitroacetamidine undergoes a useful cyclocondensation with β-diketones to produce substituted 2-amino-3-nitropyridines. Use of an acylpyruvate generates hitherto unreported 2-amino-3-nitropyridine-4-carboxylates. These may be converted easily to functionalized imidazo[4,5-b]pyridines and oxazolo-[5,4-b]pyridines.

The synthesis, biological evaluation, and structure-activity relationships of a series of 1-naphthols bearing carbon substituents at the 2-position are described. These compounds are potent inhibitors of the 5-lipoxygenase from RBL-1 cells and also inhibit bovine seminal vesicle cyclooxygenase. Structure-activity relationships for these two enzymes are different, implying specific enzyme inhibition rather than a nonspecific antioxidant effect. 2-(Aryl-methyl)-1-naphthols are among the most potent 5-lipoxygenase inhibitors reported (IC50 values generally 0.01-0.2 microM) and show excellent antiinflammatory potency in the mouse arachidonic acid ear edema model. To study the effects of structure on in vitro and in vivo activity, four general features of the molecules were varied: the 2-substituent, the 1-hydroxyl group, substitution on the naphthalene rings, and the 1,2-disubstituted naphthalene unit itself. 2-Benzyl-1-naphthol (5a, DuP 654) shows a very attractive profile of topical antiinflammatory activity and is currently in clinical trials as a topically applied antipsoriatic agent.