Synthesis
General procedure for the synthesis of pyridine-3-sulfonyl chloride hydrochloride from 3-pyridinesulfonic acid: 3-pyridinesulfonic acid (3.00 g, 18.8 mmol) was mixed with phosphorus pentachloride (PCl5, 4.79 g, 23.0 mmol) in phosphorus oxychloride (POCl3, 6 mL). The reaction mixture was stirred and reacted at 120°C overnight (15 h). After completion of the reaction, it was cooled to room temperature, diluted with chloroform (CHCl3, 20 mL) and saturated with hydrogen chloride gas (HCl(g)). The precipitated white precipitate was collected by filtration, washed with chloroform and dried under reduced pressure to give the title compound pyridine-3-sulfonyl chloride hydrochloride (3.36 g, 83% yield) as a white powder.
References
[1] Advanced Synthesis and Catalysis, 2004, vol. 346, # 8, p. 925 - 928
[2] Patent: WO2008/3703, 2008, A1. Location in patent: Page/Page column 82
[3] Patent: US2007/60623, 2007, A1. Location in patent: Page/Page column 24
[4] Patent: WO2006/36024, 2006, A1. Location in patent: Page/Page column 160
[5] Patent: EP2336107, 2015, B1. Location in patent: Paragraph 0306
