6-Chloropyridine-3-sulfonamide

6684-39-5

40741-46-6

The general procedure for the synthesis of 6-chloro-3-sulfapyridine from 2-chloropyridine-5-sulfonyl chloride was as follows: 6-chloropyridine-3-sulfonyl chloride (5.0 g, 0.024 mol) was dissolved in a 0.5 M ammonia dioxane solution (125 mL) at -50 °C. The reaction mixture was slowly warmed to room temperature and stirred continuously for 1 hour. After completion of the reaction, the mixture was filtered through diatomaceous earth and the filter cake was washed twice with dioxane. The filtrate was concentrated in vacuum to afford 6-chloropyridine-3-sulfonic acid amide as an off-white solid in a yield of 4.55 g (98% yield). The product was analyzed by liquid chromatography (LC) under the detection condition of UV215 nm; retention time (Rt) 1.05 min and 100% purity. Mass spectrometry (m/z) analytical result (ES+): 193/195. NMR hydrogen spectroscopy (400 MHz; d6-DMSO) data: δ 8.79 (1H, d), 8.21 (1H, dd), 7.75 (1H, d), 7.70 (2H, br s).