Phosphorus oxychloride → Methyl 6-chloropicolinate

Participants

Reaction Conditions

Reaction Steps

To 6-hydroxy-pyridine-2-carboxylic acid methyl ester (10.0 g, 71.9 mmol) was added phosphorus oxychloride (138 mL). The mixture was heated in an oil bath at 110° C. for 14 h and the excess phosphorus oxychloride was removed in vacuo. The resulting residue was cooled in an ice bath and anhydrous methanol (146 mL) was slowly added. After 15 min, half of the methanol was removed in vacuo and water (208 mL) was added. The solution was cooled in an ice bath and the precipitate was collected. The solid was dissolved in ethyl acetate and this organic phase was washed with water and then a saturated sodium bicarbonate solution. The combined aqueous layers were extracted with ethyl acetate and diethyl ether. The organic layers were combined, dried over sodium sulfate, filtered and concentrated in vacuo generating 7.47 g (61% yield, 43.5 mmol) of the title compound.

Provenance & Evidence