| 摘要 |
<p>PT--77492 A The process comprises reaction, in a solvent, of a 3-acetyl-4-alkoxy 2-methyl-2H-1,2 -benzothiazinc 1,1-dioxide with a hypo halogenite. Thus 4-alkyloxy-2-methyl 2H-1,2-benzothiazine -3-carboxylic-1,1-dioxide acids are produced, in which the alkoxy group is a methoxy, ethoxy or isopropoxy group. - Pref. the solvent is a binary mixture of methanol, ethanol or dioxane with water, the hypo halogenit is e.g sodium hypochlorite, reacted at 0-90 deg. C e.g. with 3-acetyl-4-methoxy based dioxide.</p> |
