Bromine → 5-Bromo-3-methylthiophene-2-carbaldehyde

Participants

Reaction Steps

Following the preparation as described in U.S. Publication No. 2006/0199836, Br2 (3.67 mL, 71.3 mmol) was added to a solution of 3-methylthiophene-2-carbaldehyde (8.55 mL, 71.3 mmol) in chloroform (59.4 mL) dropwise at 0° C. over a period of 20 min. The reaction was allowed to slowly warm to room temperature and stir for 2 h. The brown/red solution was diluted with 150 mL of CH2Cl2 and washed with water, 1.5 M K2HPO4 and brine. The organic layer was dried over anhydrous Na2SO4 and concentrated. The residue was purified by flash chromatography (silica gel, hexanes:EtOAc, 100:0 to 50:50) to afford 13.9 g (72% yield) of the title compound as a brown solid: 1H NMR (400 MHz, CDCl3) δ 9.91 (s, 1H), 6.97 (s, 1H), 2.54 (s, 3H); HPLC retention time: 2.718 min., LCMS (ES): m/z 207 [M+H]+.

Provenance & Evidence