67% |
Stage #1: 1-phenyl-2,5,8,11-tetraoxatridecan-13-ol With sodium hydroxide In tetrahydrofuran at 0 - 20℃; for 1h; Inert atmosphere;
Stage #2: 2-<2-<2-<2-(benzyloxy)ethoxy>ethoxy>ethoxy>ethyl 4-methylbenzenesulfonate In tetrahydrofuran at 0℃; for 24h; Inert atmosphere; Reflux; |
7.8. 1,27-Diphenyl-2,5,8,11,14,17,20,23,26-nonaoxaheptacosane (S18b)23
Ta solution of s16a (1.43 g; 5.02 mmol; 1.1 eq.) dissolved in anhydrous THF (40 mL), cooled to 0 °C with an icebath, NaOH (0.55 g; 13.68 mmol: 3 eq.) was added portionwise. After stirring at room temperature for 1 h, thereaction solution was cooled to 0 °C, and a solution of s17a (2.0 g; 4.51 mmol; 1 eq.) dissolved in anhydrous THF(10 mL) was added portion-wise. The resulting mixture was stirred at reflux for 24 h. After cooling to roomtemperature, water (25 mL) was added and the resulting mixture was extracted with ethyl acetate (3 x 80 mL).The combined organic layers were washed with brine (60 mL), dried over MgSO4, filtered and evaporated underreduced pressure. The mixture was purified on silica gel eluted with ethyl acetate/dichloromethane/ethanol(70/25/5; v/v/v) to afford s18b (1.21 g; 2.179 mmol; 67%). Revelator: UV. 1H NMR (200 MHz, CDCl3) 7.32 (m10H), 4.54 (s, 4H), 3.65-3.61 (m, 32H). |