Carbon Dioxide → 5-methoxy-1H-indole-7-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 7-bromo-5-methoxy-1H-indole (1.2 g) and THF (12 mL) was stirred at −78° C. under an argon atmosphere. To the reaction mixture was added dropwise an n-butyllithium n-hexane solution (1.65 M, 9.6 mL) at −50° C. or lower. The reaction mixture was stirred for 0.5 hour under ice-cooling. The reaction mixture was cooled to −78° C., and dry ice (10 g) was added thereto, followed by slowly warming to room temperature. The reaction mixture was poured into a 10% aqueous citric acid solution, followed by extraction with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (THF/hexane=20→60%) to obtain 5-methoxy-1H-indole-7-carboxylic acid (0.60 g).

Provenance & Evidence