反应详情

温度

0 °C

The product from step (b) (4.9 g) was suspended in toluene, the suspension cooled to 0° C. and a solution of potassium hydroxide (7.0 g) in water (56 ml) added dropwise. A solution of phosgene (62.5 ml of a 12% w/v solution in toluene) was added dropwise to the resulting solution over 30 minutes and stirring continued for 1 hour. The mixture was extracted with ethyl acetate and the extracts washed with brine, dried and evaporated in vacuo to give a yellow oil. Crystallisation from ethyl acetate gave the desired product as pale yellow crystals (2.3 g).

1. extractionThe mixture was extracted with ethyl acetate
2. washthe extracts washed with brine
3. customdried
4. customevaporated in vacuo
5. customto give a yellow oil
6. customCrystallisation from ethyl acetate