Methyclothiazide: C~9~H~11~Cl~2~N~3~O~4~S~2~. Mw: 360.24. (1) 2H-1,2,4-Benzothiadiazine-7-sulfonamide, 6-chloro-3-(chloromethyl)-3,4-dihydro-2-methyl-, 1,1-dioxide, (±)-; (2)(±)-6-Chloro-3-(chloromethyl)-3,4-dihydro-2-methyl-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide. CAS-135-07-9 (1963).