Synthesis
General procedure for the synthesis of 4-bromo-3-hydroxymethylbenzonitrile from 4-bromo-3-methylbenzonitrile: 4-bromo-3-methylbenzonitrile (10.0 g, 49.5 mmol) was dissolved in carbon tetrachloride (200 mL), and N-bromosuccinimide (8.81 g, 49.5 mmol) and 2,2'-azino-bis (isobutyronitrile) (414 mg. 5 mol%). The reaction mixture was refluxed for 3 hours. After completion of the reaction, water was added and the mixture was extracted with chloroform. The organic layer was washed with brine and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure. To the residue, dimethylformamide (150 mL) and sodium acetate (20.5 g, 250 mmol) were added and the mixture was stirred at 80 °C overnight. After the reaction was completed, water was added and the mixture was extracted with ether. The organic layer was washed sequentially with water and brine and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure. Methanol (150 mL) and 1 mol/L sodium hydroxide solution (50 mL) were added to the residue and stirred for 1 hour at room temperature. The reaction mixture was concentrated under reduced pressure to about one-third volume. Water and hydrochloric acid were added and the mixture was extracted with ethyl acetate. The organic layer was washed sequentially with water and brine and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure and the residue was purified by silica gel column chromatography (3:1 hexane/ethyl acetate) and finally ground with dichloromethane to give 4-bromo-3-hydroxymethylbenzonitrile (4.63 g, 44% yield).1H NMR (300 MHz, DMSO-d6) δ (ppm) 4.51 (d, J=5.9 Hz, 2H), 5.67 (t, J=5.6 Hz, 1H), 7.67 (dd, J=8.2,2.0 Hz, 1H), 7.80 (s, J=8.2 Hz, 1H), 7.83 (d, J=2.0 Hz, 1H).
References
[1] Patent: US2007/265226, 2007, A1. Location in patent: Page/Page column 58-59
[2] Journal of Medicinal Chemistry, 2006, vol. 49, # 15, p. 4447 - 4450
[3] Tetrahedron, 2011, vol. 67, # 52, p. 10082 - 10088
[4] Patent: WO2017/151489, 2017, A1
[5] Patent: WO2018/156554, 2018, A1
