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With potassium carbonate; In N,N-dimethyl-formamide; at 0℃; for 12h;Inert atmosphere; |
3,4,5,6-<strong>[1835-65-0]Tetrafluorophthalonitrile</strong> (4, 768.7 mg, 3.84 mmol) and potassium carbonate (531.0 mg, 3.84 mmol) were dissolved into dry DMF (5 mL) under nitrogen atmosphere. To this solution, 1,2,3,4-di-O-isopropylidene-alpha-D-galactopyranose (5, 1.00 g, 3.84 mmol) in DMF (5 mL) was slowly dropwised at 0 °C and stirred for 12 h. Water was added into the mixture and solids were filtered. The solids were purified by silica gel column chromatography (benzene:AcOEt = 98:2) to furnish 3a as white powder (588.2 mg, 35percent). The product 3a contained a trace amount of regioisomer 3b (3a:3b = 17:1, determined by 19F NMR). This was used for the next reaction without further purification. Major component: 1H NMR (CDCl3, 200 MHz) delta 5.38 (1 H, d, J 4.8 Hz), 4.65-4.59 (1 H, m), 4.58-4.54 (2 H, m), 4.33-4.23 (2 H, m), 4.14-4.09 (1 H, m) 1.50 (3 H, s), 1.42 (3 H, s), 1.32 (6 H, s); 19F NMR (CDCl3, 188 MHz) delta -118.7 (1F, dd, J 10.2 Hz, J 13.2 Hz), -127.6 (1F, dd, J 10.2 Hz, J 20.0 Hz), -132.8 (1F, dd, J 13.2 Hz, J 20.0 Hz); 13C NMR (CDCl3, 151 MHz) delta 154.7, 153.0, 151.0, 149.2, 148.5, 146.7, 142.7, 142.6, 142.5, 109.9, 109.3, 109.0, 96.0, 74.3, 70.7, 67.5, 25.9, 25.8, 24.8, 24.4; IR (KBr) nu 2989, 2933, 2245, 1620, 1583, 1504, 1486, 1541, 1403, 1386, 1309, 1290, 1255, 1215, 1165, 1110, 1092, 1067, 1011, 974, 925, 913, 884, 854, 796, 774, 696, 650, 632 cm-1; element. anal. Found: C, 54.55; H, 4.35; N, 6.36. Requires: C, 54.61; H, 4.53; N, 6.36percent; MS (EI) m/z 425 (M+-Me); minor component: 19F NMR (CDCl3, 188 MHz) delta -128.7 (1F, dd, J 8.6 Hz, J 19.7 Hz), -134.6 (1F, dd, J 8.5 Hz, J 19.7 Hz), -143.5 (1F, t, J 19.7 Hz). |