Acetic Acid → 5-broMo-2-chloropyridine-3-sulfonyl chloride

Participants

Reaction Steps

To a solution of 3-amino-5-bromo-2-chloropyridine (0.23 g, 1.1 mmol) in acetonitrile (3.0 mL) at −15° C. was added a solution of sodium nitrite (0.091 g, 1.3 mmol) in water (1.20 mL), followed by the addition of concentrate hydrochloric acid (1.8 mL, 21.3 mmol) and the reaction mixture was stirred for 5 minutes. A 30 wt % solution of sulfur dioxide in acetic acid 3.0 mL, 1.3 mmol) was prepared and introduced into the reaction mixture, followed by the addition of a solution of copper(II) chloride 0.091 g, 0.68 mmol) in water (1.2 mL). The stirring was continued for an additional 3 hours at −5° C. The pH of the mixture was adjusted to 8 by the addition of a solution of potassium hydrogenphosphate and 2M aqueous sodium hydroxide and partitioned with ethyl acetate (50 mL). The organic layer was separated and washed with water (10 mL) and brine (10 mL), dried over sodium sulfate, filtered and concentrated to give 5-bromo-2-chloropyridine-3-sulfonyl chloride (0.20 g, 63%).

Provenance & Evidence