Carbon Dioxide → 2-Methoxyquinoline-6-carboxylic acid

Participants

Reaction Steps

n-Butyl lithium (63 cm3 of a 1.6M solution in hexane) was added dropwise to a stirred solution of 6-bromo-2-methoxyquinoline (20 g) in THF (250 cm3) at -70° under nitrogen. After 0.5 hours, solid carbon dioxide (50 g) was added, the solution was allowed to warm to room temperature, and volatile material was removed in vacuo. The residue was partitioned between dichloromethane (100 cm3) and water (100 cm3), the aqueous phase was separated and acidified to pH 3.5 with 5M hydrochloric acid. The precipitated solid was filtered and dried (14.2 g). Recrystallisation of a small portion from isopropanol afforded 2-methoxyquinoline-6-carboxylic acid, m.p. 220°-222°.

Provenance & Evidence