Carbon Dioxide → 4-Methylthiophene-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 3-bromo-4-methylthiophene (2.7 g, 15.6 mmol) in THF (35 mL) was added n-BuLi (1.6 M in hexane, 14.6 mL, 23.3 mmol) at −78° C. dropwise over a period of 15 min and the mixture was stirred at −78° C. for 30 min. The CO2 (gaseous) was passed through the reaction mixture for 10 min and the mixture was stirred at the same temperature for 20 min. Thereafter, the reaction mixture was warmed to 0° C., quenched with aqueous 1 M NaOH (60 mL) and washed with EtOAc (2×50 mL). The aqueous layer was acidified to pH ˜5 and extracted with DCM (2×50 mL). The combined organic layers were washed with water (100 mL), brine (100 mL), dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, 8% MeOH/DCM as eluent) to provide compound A56-1 (1.5 g, 70%) as a white solid.

Provenance & Evidence