| 摘要 |
<p>PT--81459 A 4-Alkoxy 2-methyl 2H-thieno (2,3-e)-1,2-thiazine 1,1-dioxide 3-carboxylic acids are made by (a) reacting an alkyl ester of 4-hydroxy 2-methyl 2H-thieno (2,3-e)-1,2-thiazine 1,1-dioxide 3-carboxylic acid with an alkylating agent in inert solvent in presence of sodium or potassium carbonate; and (b) treating the prod. with an aq. soln. of sodium or potassium hydroxide and isolating the corresp. acid with mineral acid. - The alkylating agent is pref. methyl, ethyl, isopropyl or benzyl iodide, ethyl, isopropyl or benzyl bromide, benzyl chloride or dimethyl sulphate. The inert solvent can be acetonitrole, acetone, dioxane, tetrahydrofurane, DMF, DMSO, pyridine and their binary mixts.</p> |
