Dimethyl allylmercaptoacetal

Amino-2-chloro-5-(methylsulfamyl)benzenesulfonamide Dimethyl allylmercaptoacetal... 

To 6.75 g (0.0225 mole) of 4-amino-2-chloro-5-(methylsulfamyl) benzenesulfonamide in 45 ml of dimethylformamide is added 4.86 g (0.03 mole) of dimethyl allylmercaptoacetal followed by 1.5 ml ethyl acetate saturated with hydrogen chloride gas. The solution is refluxed for 1.5 hours, cooled and added dropwise with stirring to ice/water. The resulting precipitate is filtered, dried and recrystallized from isopropanol. The recrystallization gave 4.0 g of 2-methyl-3-allylthiomethyl-6-chloro-7-sulfamyl-3,4-dihydro-l,2,4-benzothiadiazine-1,1-dioxide M.P. 168.5-170°C. 

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