Abstract
The structure of previously reported new antiinflammatory agent (1, FK3311) was chemically modified in an attempt to find novel compounds with more potent and broader-spectrum activities. Some 2'-(phenylthio) and 2'-(phenylamino)methanesulfonanilides (2 and 3), in particular those bearing an electron-attracting substituent at the 4'-position, potently inhibited adjuvant arthritis in rats as well as collagen-induced arthritis in mice when administered orally. 4'-Carbamoyl-2'-(2, 4-difluorophenylthio)methanesulfonanilide (3b), which was selected as a candidate for further development from among the compounds synthesized herein, exhibited activity in reducing arthritis in a spontaneous autoimmune disease model (MRL/lpr mice) within the dose range of 10-100 mg/kg (p.o).