Thionyl Chloride → 6-Bromopyridine-2-carbonyl chloride

Participants

Reaction Steps

4 g of 6-bromopyridine-2-carboxylic acid and 25 g of thionyl chloride are refluxed for 1 hour. The excess thionyl chloride is removed in a vacuum and the residue is distilled on a bulb tube at 110° C. and 0.04 mbar. The 6-bromopyridine-2-carboxylic acid chloride thus obtained is dissolved together with 3.32 g of 4-aminobutyric acid ethyl ester, hydrochloride in 40 ml of dioxane, mixed under ice cooling with 6 g of triethylamine and stirred for 5 hours at room temperature. The reaction mixture is added to water, extracted with diethyl ether, dried (sodium sulfate) and concentrated by evaporation. The residue is distilled on a bulb tube at 170° C. and 0.04 mbar and 3.2 g of 4-(6-bromo-2-pyridylcarbonylamino)-butyric acid ethyl ester is thus obtained as bright yellow oil.

Provenance & Evidence