Metabolism of a Nonsteroidal Antiinflammatory Agent to the starting ester in DMSO, a slurry of NaOCHs in DMSO was added with stirring over a 1-hr period while maintaining the temp below 30°. After complete addn and 15 min of addl stirring, acidification (qxcess 3 N HC1), filtration, and recrystn (IPO) gave a 59% yield of the desired estgr Ic.2-Methyl-4-hydroxy-277-l,2-benzothiazine-3-carboxylic AcidMethyl Ester 1,1-Dioxide (VI).-A yellow soln resulted from a combination of 2.95 g (0.012 mole) of 4-hy droxy-277-1,2-benzothiazine-3-carboxylic acid methyl ester 1,1-dioxide, 2.4 ml of Mel, 11 ml of H20, 40 ml of EtOH, and 12 ml of 1 N NaOH.After standing at room temp for 18 hr the resulting heavy yellow ppt was filtered, washed with H20, and dried to give 2.4 g (78%) of VI, mp 162-165°. A sample in MeOH soln gave a wine-red color with 5% FeCI3.; Titration in 2:1 dioxane-H20 indicated neut equiv 266 (caled 269) and pffa = 8.4; nmr (DCC13) -2.04 (s, 1, exchanges with D20, enol OH), 1.8-2.4 (m, 4, arom protons), 6.05 (s, 3, OCHO, 7.06 (s, 3, NCH3). Anal. (CnH"N05S) C, H, N.By an analogous alkylating procedure using either Etl, PrI, allyl bromide, or benzyl bromide the corresponding 2-aIkyl-4hydroxy-277-l,2-benzothiazine-3-carboxylic acid methyl ester 1.1-dioxides were made (see Table IV).2-Benzyl-and 2-AUyl-2H-l,2-benz