5-Bromo-pyridine-2-sulfonyl chloride

Synthesis

Example 52(b) Synthesis of 5-bromopyridine-2-sulfonyl chloride: 2-(benzylthio)-5-bromopyridine (3.0 g, 10.71 mmol) was dissolved in dichloromethane (500 mL) in a 1 L Schlenk flask, followed by addition of water (250 mL) and formic acid (250 mL). The resulting non-homogeneous mixture was cooled to 0°C and chlorine gas was bubbled into the mixture through a Pasteur pipette under vigorous stirring. The chlorine gas was continuously passed for three minutes or until the mixture took on a deep yellow color. Upon completion of the reaction, the organic phase was separated and diluted with dichloromethane (100 mL). The aqueous phase was extracted with dichloromethane (3 x 250 mL) and the combined organic phases were washed sequentially with 1 M sodium hydroxide solution (500 mL) and saturated brine (500 mL). The organic phase was dried over anhydrous sodium sulfate and concentrated to afford the target product 5-bromopyridine-2-sulfonyl chloride (2.73 g, 99% yield). Mass spectrum (ESI) m/z 258 ([M+H]+).

References

[1] Patent: WO2008/2244, 2008, A2. Location in patent: Page/Page column 71-72
[2] Patent: US2015/51395, 2015, A1. Location in patent: Paragraph 0182; 0796
[3] Patent: US2016/244451, 2016, A1. Location in patent: Paragraph 0334; 0335
[4] Patent: WO2006/10629, 2006, A1. Location in patent: Page/Page column 55
[5] Patent: WO2014/178, 2014, A1. Location in patent: Page/Page column 58; 59