反应详情

To a stirred solution of the product of stage (a) (266 g) in 4 N aqueous sodium hydroxide (900 ml), dimethyl sulphate (192 ml) was added whilst maintaining the temperature at 35°-40° C. The mixture was stirred for 5 minutes, then 4 N aqueous sodium hydroxide (450 ml) was added and dimethyl sulphate (96 ml) was added dropwise. The temperature rose to 55° C. The mixture was then stirred overnight, and the product was extracted into dichloromethane, washed with water, dried over magnesium sulphate, filtered, and the solvent evaporated off to give a brown oil (280 g). Distillation gave the title product as a colourless oil, bp 96°-98° C./0.3 mm Hg.

1. temperaturewhilst maintaining the temperature at 35°-40° C
2. customrose to 55° C
3. stirringThe mixture was then stirred overnight
4. extractionthe product was extracted into dichloromethane
5. washwashed with water
6. dry with materialdried over magnesium sulphate
7. filtrationfiltered
8. customthe solvent evaporated off