[Synthesis]
General procedure for the synthesis of 3-fluoro-5-methylphenol from 1-fluoro-3-methoxy-5-methylbenzene:
(40b) Synthesis of 1-fluoro-5-methylphenol
In Example (40a), 1-fluoro-3-methoxy-5-methylbenzene (0.92 g, 6.56 mmol) was dissolved in dichloromethane (20 mL), boron tribromide (1.0 M solution in dichloromethane, 8.53 mL, 8.53 mmol) was added, and the reaction was stirred for 10 hours at 0°C. After completion of the reaction, water (100 mL) was added to the reaction mixture and extracted with dichloromethane (100 mL). The organic layers were combined and dried over anhydrous sodium sulfate. After concentration under reduced pressure, the residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate, 1:1) to afford 3-fluoro-5-methylphenol (0.83 g, yield: 99%) as a yellow oil.
1H-NMR (CDCl3, 400 MHz) δ: 2.06 (3H, s), 4.97 (1H, s), 6.37 (1H, dt, J = 2.4, 10.2 Hz), 6.44 (1H, s), 6.48 (1H, d, J = 8.6 Hz). |