Carbon Dioxide → 1-Butylisoquinoline-7-carboxylic acid

Participants

Reaction Steps

To a −60° C. solution of 7-bromo-1-butylisoquinoline prepared in step 1 (940 mg, 3.55 mmol) in diethyl ether (15 mL) was added sec-butyl lithium (3.0 mL, 1.3 M cyclohexanes, 3.90 mmol) to yield a dark green solution. The reaction mixture was stirred at −60° C. for an additional 15 minutes at which time carbon dioxide gas was bubbled through the solution for 20 minutes with the aid of a gas dispersion tube. The resulting solution was then allowed to warm to room temperature and concentrated under reduced pressure to yield a pink solid. The residue was partitioned between ethyl acetate and water and then acidified to pH 7 with 1 N hydrochloric acid. The aqueous phase was extracted again with ethyl acetate and the combined organic phases were washed with saturated sodium chloride, dried (sodium sulfate), filtered, and concentrated to yield 1-butylisoquinoline-7-carboxylic acid (299 mg). ESI MS m/z 230 [M+H]+.

Provenance & Evidence