Studies on anti-inflammatory agents. VI. Synthesis and pharmacological properties of 2,3-diarylthiophenes

A series of novel 5-substituted-2,3-diarylthiophenes has been synthesized and found to be active in the rat adjuvant arthritis (AA) model and/or in the yeast-induced hyperalgesia (Randall-Selitto) assay. Among the compounds synthesized herein, 2-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)thiophene (6a) exhibited the most potent activities on AA, collagen-induced arthritis (CIA) and the delayed-type hypersensitivity response to type II collagen. 5-Bromo-2-[4-(methylamino)phenyl]-3-[4-(methylsulfinyl)phenyl]thiophene (38) is also a potent inhibitor of AA, CIA, hyperalgesia and in vitro tumor necrosis factor-α production.