Triethylamine → 1-(3,4-Dichlorophenyl)-2-pyridin-4-yl-ethane-1,2-dione

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Reaction Conditions

Reaction Steps

Dimethylsulfoxide (37 ml, 0.53 mol) was dissolved in dichloromethane (250 ml) and cooled to −78° C. Oxalyl chloride (34.5 ml, 0.40 mol) was added dropwise and the solution stirred for 20 min. A solution of the product of Step 1 (34 g, 0.12 mol) in dimethylsulfoxide (40 ml) and dichloromethane (200 ml) was added dropwise at −78° C., and the solution stirred for 30 minutes. Triethylamine (104 ml, 0.74 mol) was added dropwise and the solution became floculent such that overhead stirring became necessary. The solution was allowed to stir at room temperature over 2 hours then was poured on to ice/saturated sodium bicarbonate solution. The aqueous layer was separated, and re-extracted with dichloromethane. The combined organic phases were concentrated under reduced pressure to a green-yellow solid. The solid was redissolved in dichloromethane and washed with water and brine, dried (MgSO4) and evaporated to a solid. The crude solid was purified by silica gel chromatography eluting with dichloromethane, to afford the title compound (28.66 g, 85%) as a yellow solid; MS(-ve ion) m/e 279/281/283 [M−H]−.

Provenance & Evidence