反应详情

The compound from Step E (5.2 g, 19 mmol), ethylene glycol (4.4 g, 71 mmol) and a catalytic amount of p-toluenesulfonic acid (0.2 g) were dissolved in benzene (300 mL) and refluxed for 28 h. The solvent was removed and the crude product chromatographed on silica gel with hexane/ethyl acetate (2:1) to yield 3.6 g (60%) of the title compound. 1H-NMR (400 MHz, CDCl3) δH 1.75 (3H, s, CH3), 3.82 (2H, t, OCH2), 3.91 (3H, s, OCH3), 4.10 (2H, t, OCH2), 6.93 (1H, s, ArH), 6.98 (1H, d, ArH), 7.47 (3H, m, ArH), 8.04 (1H, s, ArH).

1. temperaturerefluxed for 28 h
2. customThe solvent was removed
3. customthe crude product chromatographed on silica gel with hexane/ethyl acetate (2:1)