反应详情

A solution of triphosgene (16.7 g) in ethyl acetate (130 mL) was heated to reflux and a suspension of the title compound of Step D (4.9 g) in ethyl acetate was added via cannula and the aid of a mechanical pump over a period of 40 min. The temperature was held at approximately 75° C. during the addition. After the addition was complete, the reaction mixture was heated at reflux for 2 h, cooled to room temperature and stirred overnight at room temperature. The reaction mixture was poured into a solution of saturated aqueous sodium bicarbonate, extracted with ethyl acetate, and the combined organic extracts were dried (MgSO4), filtered and concentrated under reduced pressure to afford 4.9 g of the title compound of Step E as a white solid melting at 142-143° C. 1H NMR (CDCl3): δ 7.93 (dd,1H), 7.84 (d,1H), 7.43 (m,2H), 7.24 (dd,1H), 6.75 (d,1H), 3.87 (s,3H), 3.62 (s,3H).

1. temperatureto reflux
2. additionwas added via cannula
3. additionThe temperature was held at approximately 75° C. during the addition
4. additionAfter the addition
5. temperaturethe reaction mixture was heated
6. temperatureat reflux for 2 h
7. extractionextracted with ethyl acetate
8. dry with materialthe combined organic extracts were dried (MgSO4)
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure