General procedure for the synthesis of (5-bromo-2-nitrophenyl)methanol from 5-bromo-2-nitrobenzoic acid: to a solution of 5-bromo-2-nitrobenzoic acid (280 g, 1.14 mol, 1.0 eq.) in tetrahydrofuran (THF, 1.5 L) was slowly added dropwise a THF solution of 10 M borane-dimethyl sulfide (BH3-Me2S) (119.7 mL, 1.05 equivalent) for 30 min. After dropwise addition, the reaction mixture was heated to 70 °C and maintained at this temperature for 3 hours. Upon completion of the reaction, the mixture was cooled to 0 °C and methanol (MeOH, 100 mL) was slowly added to quench the reaction, followed by concentration under reduced pressure. To the concentrated residue was added a mixed petroleum ether/ethyl acetate solvent (1000 mL, 10:1 volume ratio) and stirred for 1 hour. The precipitate precipitated was collected by filtration to afford the target product (5-bromo-2-nitrophenyl)methanol (160 g, 689 mmol, 60.49% yield) as a white solid. The product was confirmed by 1H NMR (400 MHz, chloroform-d): δ=7.98-7.91 (m, 2H), 7.55 (dd, J=1.8,8.8 Hz, 1H), 4.97 (br.s., 2H), 2.77 (br.s., 1H). The mass spectrum (ESI) showed [M+H]+ peaks of 232.2/234.2.
