Hydrochloric Acid → 1-Chloro-3-isopropylsulphonylpyridine

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Reaction Steps

The 1-cyano-1-isopropylsulphonyl-4-dimethylamino-1,3-butadiene (34 g, 0.15 mol) obtained in (a) above was dissolved in isopropanol (350 ml). The solution was then heated to reflux and saturated with dry hydrogen chloride. After about 20 hours, the solution was cooled and poured into water and crushed ice. This solution was then neutralised with sodium hydroxide solution and extracted with toluene (5×100 ml). The combined extracts were then evaporated and the remaining brown syrup purified over silica using 1:1 toluene:ethyl acetate as eluant to leave an oil which yielded 7 g 1-chloro-3-isopropylsulphonylpyridine as yellow crystals, m.pt. 82°-84° C., after stirring with petroleum ether. Yield: 51.5% of the theoretical.

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