4-Bromothiophene-2-carbaldehyde → 4-Bromo-2-thiophenecarboxylic Acid

Participants

Reaction Conditions

Reaction Steps

4-Bromothiophene-2-carbaldehyde (1.9 g, 10 mmol) was dissolved in 40 mL of t-BuOH and 4 mL of 2-methyl-2-butene. The reaction mixture was cooled to 0° C. and NaClO2 (1.1 g, 12 mmol) dissolved in 12 mL of 1M NaH2PO4 was added. The reaction mixture was let warm to room temperature and stirred for 5 hours. The reaction mixture was concentrated to about half the volume, and poured into 20 mL 1N NaOH and 50 mL Et2O. The aqueous layer was made acidic with 6N HCl and extracted with EtOAc. This organic layer was dried over sodium sulfate and concentrated to obtain the product as a white solid, 1.75 g, 8.5 mmol, 85% yield. 1H NMR 500 MHz (DMSO-d6) 8.02 (1H, s), 7.78 (1H, s).

Provenance & Evidence