Dimethyl Sulfoxide → 2-Bromo-4-chlorobenzaldehyde

Participants

Reaction Conditions

Reaction Steps

To a 0° C. solution of (2-bromo-4-chloro-phenyl)-methanol (5.57 g, 0.025 mol), dichloromethane (250 mL), diisopropylethylamine (22 mL, 0.126 mol), and dimethyl sulfoxide (15 mL, 0.211 mol) was added sulfur trioxide-pyridine (12.0 g, 0.075 mol), in portions, over 15 minutes. The resulting solution was stirred at 0° C. for 45 minutes. The reaction mixture was diluted with 250 mL dichloromethane, then washed with saturated aqueous NaHCO3 (500 mL). The organic phase was washed with saturated aqueous sodium thiosulfate (500 mL) to reduce excess oxidant. The organic phase was dried over Na2SO4, filtered and concentrated to afford a yellow oily solid. A solution of this crude product and CH2Cl2 (200 mL) was evaporated onto silica gel, and the dry silica gel-supported product was loaded onto a 120 g silica gel column. Flash chromatography was carried out using an ISCO purification system (95:5 hexanes-ethyl acetate). 2-Bromo-4-chloro-benzaldehyde was isolated as 4.43 g (81% yield) of a white solid. 1H NMR (300 MHz, CDCl3) δ ppm 10.31 (s, 1 H), 7.88 (d, J=8.2 Hz, 1 H), 7.69 (d, J=1.6 Hz, 1 H), 7.44 (dd, J=8.2, 1.6 Hz, 1 H).

Provenance & Evidence