反应详情

A solution of 11.38 g (51 mmol) of methyl 4-methylbenzo-thiazol-2-one-5-carboxylate in 400 ml of acetone was admixed with 14.18 g of potassium carbonate. 5.1 ml (54 mmol) of dimethyl sulfate were then added dropwise with stirring, and the mixture was stirred at 23° C. for 78 hours. The precipitated solid was filtered off and the solvent was removed under reduced pressure. Recrystallization from ether gave, in a yield of 84%, 10.15 g (43 mmol) of methyl 3,4-dimethylbenzothiazol-2-one-5-carboxylate of m.p. 97° C.-100° C.

1. stirringthe mixture was stirred at 23° C. for 78 hours
2. filtrationThe precipitated solid was filtered off
3. customthe solvent was removed under reduced pressure
4. customRecrystallization from ether