100% |
With potassium carbonate; In N,N-dimethyl-formamide; at 75℃; for 6h; |
(i) Production of 2-(4-bromophenoxy)-5-fluoronitrobenzene (2) Potassium carbonate (5.64 g, 40.8 mmol) was added to an N,N-dimethylformamide solution (100 ml) of p-bromophenol (5.43 g, 31.4 mmol), and <strong>[364-74-9]2,5-difluoronitrobenzene</strong> 1 (5.00 g, 31.4 mmol) further was added thereto. The resulting mixture was stirred at 75C for 6 hours. Distilled water was added to the resulting reaction solution, and then extraction was carried out with ethyl acetate (* 3). The combined organic layers were washed successively with 1N hydrochloric acid, a 2N aqueous sodium hydroxide solution, a saturated aqueous sodium hydrogencarbonate solution, and saturated brine. The organic layer was dried over anhydrous sodium sulfate and then concentrated in vacuo. The residue thus obtained was purified by silica gel chromatography (silica gel: 200 g, eluant: hexane/ethyl acetate = 15/1), thereby giving the title compound (9.87 g, quantitative) as orange crystals. TLC Rf 0.42 (hexane/ethyl acetate = 15/1). 1H NMR (CDCl3, 400 MHz)delta: 7.05-7.10 (dd, 1H, aromatic, J = 9.1, 4.6 Hz), 7.26-7.32 (ddd, 1H, aromatic, J = 9.2, 7.2, 3.2 Hz), 7.46 (d, 1H, aromatic, J = 2.2 Hz), 7.48 (d, 1H, aromatic, J = 2.1 Hz), 7.70-7.74 (dd, 1H, aromatic, J = 7.5, 3.2 Hz). 13C NMR (CDCl3, 100 MHz) delta: 113 (d, 2JC-F = 27.3 Hz), 116.8, 121.3, 121.6 (d, 2JC-F= 27.2 Hz), 123.2, 123.5 (d, 3JC-F = 2.8 Hz), 127.4, 131.1, 145.6 (d, 3JC-F = 3.3 Hz), 156.4 (d, 1JC-F = 249.1 Hz), 157.2. IR (KBr, cm-1): 504, 556, 772, 812, 876, 945, 1009, 1069, 1129, 1165, 1208, 1256,1347,1415,1482,1538,2584,3094. |