反应详情

Trifluoroacetic anhydride (1.3 ml, 9.36 mmol) was added to a solution of 4-hydroxy-2-methoxybenzamide {Liebigs Ann Chem (1982)1836-1869} (600 mg, 3.6 mmol) and pyridine (0.72 ml, 9.36 mmol), in tetrahydrofuran (10 ml), and the mixture was stirred at room temperature for 18 hours. The reaction mixture was then concentrated under reduced pressure and treated with 2M hydrochloric acid (100-ml). It was then extracted with ethyl acetate (2×100 ml). The organic layers were combined and washed with brine (100 ml), dried over magnesium sulphate, filtered and then evaporated under reduced pressure to give an orange solid. The crude product was purified by flash chromatography on silica gel eluting with pentane:ethyl acetate (70:30 to 50:50, by volume) to provide the title compound (320 mg, 60%) as a pale yellow solid.

1. concentrationThe reaction mixture was then concentrated under reduced pressure
2. additiontreated with 2M hydrochloric acid (100-ml)
3. extractionIt was then extracted with ethyl acetate (2×100 ml)
4. washwashed with brine (100 ml)
5. dry with materialdried over magnesium sulphate
6. filtrationfiltered
7. customevaporated under reduced pressure
8. customto give an orange solid
9. customThe crude product was purified by flash chromatography on silica gel eluting with pentane:ethyl acetate (70:30 to 50:50, by volume)