反应详情

温度

60 °C

To a solution of compound from preparation 369 (31 g, 0.2 mol) in ethanol (anhydrous, 310 ml) was added p-toluenesulfonic acid monohydrate (1.9 g, 10 mmol, 0.05 equiv.) and triethyl orthoformate (50 ml, 0.3 mol). The reaction mixture was stirred at 60° C. overnight. The volatiles were stripped and the residue was diluted with ethyl acetate (250 ml), washed with water (120 ml) and brine (100 ml), and dried over MgSO4. After filtration and evaporation, the residue was purified by chromatography. Eluting the column with 10% ethyl acetate in hexane afforded the title compound (40 g, 87.7% yield).

1. washwashed with water (120 ml) and brine (100 ml)
2. dry with materialdried over MgSO4
3. filtrationAfter filtration and evaporation
4. customthe residue was purified by chromatography
5. washEluting the column with 10% ethyl acetate in hexane