Hydrochloric Acid → [2,4'-Bipyridine]-5-carboxylic acid hydrochloride

Participants

Reaction Steps

In tetrahydrofuran (20 ml), 6-chloronicotinic acid (535 mg) and diethyl (4-pyridyl)borane (Chem. Pharm. Bull., 33, 4755, 1985) (500 mg) were dissolved. To the resulting solution, tetrabutylammonium bromide (546 mg), potassium hydrochloride (570 mg), tetrakis(triphenylphosphine) palladium (O) (392 mg) and water (0.5 ml) were added under an argon atmosphere, followed by heating under reflux for 6 hours. Dilute hydrochloric acid was added to the reaction mixture to make it acidic. Water and ethyl acetate were poured into the resulting mixture for extraction. The water layer so extracted was distilled off under reduced pressure. The residue was purified by chromatography through a synthetic adsorbent (“Diaion® HP-20”, water˜50% acetonitrile—water). To the resulting fraction, dilute hydrochloric acid was added to make it acidic. The solvent was then distilled off. Tetrahydrofuran was added to the residue and the precipitate was collected by filtration, whereby the title compound (269 mg, 32%) was obtained.

Provenance & Evidence