Carbon Dioxide → 2-chlorothiophene-3-carboxylic Acid

Participants

Reaction Steps

To a round bottomed flask were added 2-chloro-3-bromothiophene (26.2 g, 132.7 mmole) along with diethyl ether (390 mL). The reaction was cooled to -78° C. (dry ice/acetone) and 1.6M n-butyllithium (87.0 mL, 139.0 mmole) was added dropwise. The reaction was stirred for 1.5 hours after which an excess of CO2 (~25.0 g) was added all at once. The reaction was warmed to room temperature and poured onto ice/water. The mixture was extracted with 10% sodium carbonate solution and the basic aqueous layer was washed with methylene chloride. The basic solution was then acidified to a pH 3.0 and extracted with diethyl ether. The organic layer was washed with water, brine, and dried (MgSO4). Solvent removal yielded 19.32 g of an off-white solid (90%) which was used as is.

Provenance & Evidence