Phosphorus oxychloride → Pyridine-3-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

A mixture of pyridine-3-sulfonic acid (3 g, 18.8 mmol), phosphorus pentachloride (6.04 g, 29.0 mmol) and phosphorus oxychloride (15 mL) was heated at 120° C. overnight. Excess phosphorus oxychloride was evaporated under reduced pressure, the residue quenched with ice and partitioned between water and diethyl ether. The pH of the aqueous phase was adjusted by addition of solid sodium bicarbonate to pH 7-8, then the organic layer was separated and washed successively with sat. sodium bicarbonate solution, water and brine. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to give a residue which was dried under high vacuum to afford pyridine-3-sulfonyl chloride (2.83 g, 85%) as a solid.

Provenance & Evidence