Carbon Dioxide → 2,6-Dichlorpyridine-3-carbonyl chloride

Participants

Reaction Conditions

Reaction Steps

(1)-1 2,6-Dichloropyridine (20 g) was dissolved in tetrahydrofuran (200 ml), and, to the resulting solution, there was added dropwise a solution of n-butylithium (1.6M) in n-hexane (84.5 ml) in a flow of argon gas at a temperature of -78° C. over a period of 30 minutes. After the resulting solution was stirred for one hour at the same temperature, greatly excess carbon dioxide (solid) was added. After stirring for one hour, temperature was raised to -10° C., and, then, water and hydrochloric acid were added in order so that pH might be 1-2, and, thereafter, the resultant solution was extracted with ethyl acetate. After the obtained extract was dried over anhydrous sodium sulfate, solvent was distilled off under reduced pressure to dryness. To the obtained solid, there was added thionyl chloride (40 ml), and the resulting mixture was heated to reflux for three hours. The excess thionyl chloride was distilled off under reduced pressure, and, then, crude product was distilled under reduced pressure to form 2,6-dichloronicotinoyl chloride (19.8 g).

Provenance & Evidence