反应详情

温度

45 °C

Pyridinium p-toluenesulfonate (20 mg) was added to a stirred solution of the compound [8a] (0.44 g), obtained in previous step, in methanol (20 mL) at room temperature. The mixture was stirred at 40-50° C. for 3-4 hours (TLC monitoring) and evaporated under reduced pressure. The residue was diluted with dichloromethane (30 mL). The solution was washed with saturated aqueous solution of sodium bicarbonate (10 mL) and brine(10 mL), dried over sodium sulfate, filtered and evaporated to give 0.35 g (93.4%) of oily residue. The residue was crystallized from a mixture of hexane and ether to give compound [6a] as white crystals with mp 81-83° C. and [α]D20 −124.5° (c 1, MeCN). 1H NMR (CDCl3) δ: 7.08-8.05 (m, 14H); 5.51-5.74 (m, 2H); 5.21-5.30 (m, 1H); 5.02-5.07 (m, 1H); 4.09-4.13 (m, 1H); 2.46-2.92 (m, 7H); 2.18-2.28 (m, 1H); 1.66-1.86 (m, 3H). 13C (CDCl3) δ: 31.6; 34.8; 37.6; 38.7; 42.7; 54.1; 71.6; 79.0; 83.1; 125.9; 127.1; 127.2; 128.2; 128.3; 128.8; 128.9; 130.1; 136.2; 139.9; 141.5; 146.1; 165.9; 176.2.

1. customevaporated under reduced pressure
2. additionThe residue was diluted with dichloromethane (30 mL)
3. washThe solution was washed with saturated aqueous solution of sodium bicarbonate (10 mL) and brine(10 mL)
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. customevaporated