Phosphorus oxychloride → 2-Chloro-5-nitropyridine-3-carboxylic acid

Participants

Reaction Steps

A solution of 2-hydroxy-5-nitronicotinic acid (9.2 g, 0.05 mol) in phosphorus oxychloride (25 ml) was refluxed for 5 hours. The solvent was removed in vacuo and the residue dissolved in a mixture of tetrahydrofuran and ether. After cooling the solution in an ice bath, water was cautiously added dropwise with stirring until a clean separation of layers was obtained. The organic layer was washed with water and a saturated sodium chloride solution, dried (anhydrous magnesium sulfate) and concentrated. Recrystallization from ether gave 6.94 g (69% of theory) of pure product, m.p. 135° C. (dec).

Provenance & Evidence