Abstract
Oxidation of 4‐[3‐(dimethylamino)propyl]‐3,4‐dihydro‐2‐(1‐hydroxyethyl)‐3‐phenyl‐2H‐1,4‐benzothiazine, hydrochloride (I) with hydrogen peroxide yielded a mixture of two sulfoxides (II). Since this mixture exhibited antiinflammatory activity, the two components (Isomers A and B) were prepared in purified form by oxidation of I withN‐chlorosuccinimide and hydrogen peroxide, respectively. Isomer A was more potent than Isomer B in the carrageenin‐induced edema test.