反应详情

Into a solution of triphosgene (51.5 g, 174 mmol) in ethyl acetate (500 mL) heated to 75° C. was pumped a slurry of the title compound of Step B (15.57 g, 62 mmol) in ethyl acetate (100 mL) over 40 min. The mixture was held at 75° C. during the entire addition and then for an additional 2 h. The mixture was cooled to room temperature and stirred overnight. The reaction mixture was poured into saturated sodium bicarbonate solution and back-extracted with ethyl acetate. The combined organic phases were dried (MgSO4) and concentrated under reduced pressure to afford the title compound of Step C (14.59 g) as an off white solid. 1H NMR (CDCl3): δ 8.01 (dd,1H), 7.58 (d,1H), 7.50 (t,1H), 3.82 (s,3H), 3.56 (s,3H), 2.28 (s,3H).

1. customover 40 min
2. additionThe mixture was held at 75° C. during the entire addition
3. extractionback-extracted with ethyl acetate
4. dry with materialThe combined organic phases were dried (MgSO4)
5. concentrationconcentrated under reduced pressure