反应详情

To a solution of the acid (0.47 g, 2.1 mmol) in dry methanol (40 ml) was added conc. Sulfuric acid (0.47 g) and the solution heated to reflux for 96 h. Upon cooling the the methanol was removed and the residue taken up in water (50 ml), and extracted with dichloromethane (3×30 ml). The combined extracts were dried (Na2SO4), and the solvent removed. The residue was eluted through a silica column using 5% ethyl acetate in petroleum spirit to yield a colorless oil (0.23 g, 46%). 1H-NMR (CDCl3, 300 MHz): δ 3.94 (s, 3H), 4.03 (s, 2H), 6.81 (t, 1H, J=8 Hz), 7.20-7.32 (m, 6H), 7.73 (dd 1H, J=8 Hz, 1.5 Hz), 11.10 (s, 1H).

1. temperaturethe solution heated
2. temperatureto reflux for 96 h
3. customwas removed
4. extractionextracted with dichloromethane (3×30 ml)
5. dry with materialThe combined extracts were dried (Na2SO4)
6. customthe solvent removed
7. washThe residue was eluted through a silica column