Oxalyl chloride → Methyl 2-bromothiophene-3-carboxylate

Participants

Reaction Steps

2-bromo-3-thiophene carboxylic acid (1.0 eq, 12.56 g, 60.66 mmol) was suspended in CH2Cl2 (200 ml). Oxalyl chloride (1.1 eq, 5.9 ml, 67.16 mmol) and 5 drops of DMF were added, inducing formation of gas. The mixture was stirred overnight at room temperature and the volatiles were removed in vacuo. The resulting solid was suspended in dry methanol (150 ml) and the mixture heated to ebullition. Evaporation of the solvents afforded methyl 2-bromo-3-thiophene carboxylate (13.16 g, 98% yield) as a crude brown oil. LCMS (ES): 99% pure, m/z not detected; 1H NMR (CDCl3, 400 MHz) δ 3.88 (s, 3H), 7.23 (d, J=5.6, 1H), 7.56 (d, J=5.6, 1H) ppm.

Provenance & Evidence