Phosphorus oxychloride → Pyridine-3-sulfonyl chloride

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Reaction Steps

To 1.2 g of 3-pyridine sulfonic acid (Aldrich Chemical Co.) is added 1.70 g of PCl5 and 5.4 ml of POCl3. The reaction mixture is heated to reflux temperature and allowed to stir at reflux for 5 hours. The reaction mixture is cooled to room temperature and evaporated to dryness under vacuum. The solid residue is distributed between methylene chloride and saturated aqueous sodium bicarbonate solution and the organic phase is washed twice with aqueous bicarbonate solution followed by drying over anhydrous sodium sulfate. The organic solution is evaporated to dryness to give 900 mg of the title compound which is used directly in the preparation of sulfonamides.

Provenance & Evidence