Dimethyl Sulfate → methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide

Participants

Reaction Conditions

Reaction Steps

To a suspension of 90 grams (0.352 moles) of methyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide in 450 ml proprietory alcohol there is added a solution of 15.5 grams (0.3875 moles) of sodium hydroxide in 450 ml of water at a temperature of less than 20° C. 53.4 Grams (0.423 moles) of dimethyl sulphate is added while stirring, at 25° C. and the mixture is then allowed to stir for about 15 hours. It is cooled to 10° C. and filtered. The cake is washed with water, followed by a 50% alcohol/water wash, and dried. Yield is 90 grams (95%) m.p. 162.5°-164° C.

Provenance & Evidence