反应详情

m-Chloroperbenzoic acid (25.6 g) was added dropwise to a stirred solution of 2-methoxy-5-methyl-2H-1,4-thiazin-3(4H)-one (16 g) in methanol (500 ml) under ice-cooling and the mixture was stirred at room temperature for 4 hours. Then, the reaction mixture was made alkaline by addition of anhydrous potassium carbonate and evaporated to dryness. The residue was extracted twice with chloroform and the combined extracts were washed with water, dried over anhydrous magnesium sulfate and evaporated to dryness. The residue was triturated with ethyl ether to give 2,2-dimethoxy-5-methyl-2H-1,4-thiazin-3(4H)-one (10 g, yield 53%) as pale yellow plates.

1. temperaturecooling
2. customevaporated to dryness
3. extractionThe residue was extracted twice with chloroform
4. washthe combined extracts were washed with water
5. dry with materialdried over anhydrous magnesium sulfate
6. customevaporated to dryness
7. customThe residue was triturated with ethyl ether