Acetic Acid → 1-Cyano-1-isopropylsulphonyl-4-dimethylamino-1,3-butadiene

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Reaction Steps

3-Dimethylaminoacrolein (17 ml, 0.17 mol) and isopropylsulphonylacetonitrile (25 g, 0.17 mol) were dissolved in toluene (250 ml) and piperidine (1 ml) and acetic acid (2.5 ml) were then added. The solution was heated under reflux in a water separator until no more water was formed (about 3 hours). On cooling, crystals formed which were filtered off under suction and dried to give 26 g 1-cyano-1-isopropylsulphonyl-4-dimethylamino-1,3-butadiene as yellow-brown crystals, m.pt. 102°-104° C. The remaining toluene was then extracted with water (2×50 ml), dried over sodium sulphate and evaporated under vacuum to give about 15 g of a brown syrup. This was then purified over silica using ethyl acetate as eluant to give a further 8.8 g 1-cyano-1-isopropylsulphonyl-4-dimethylamino-1,3-butadiene crystals. Yield: 90.2% of the theoretical.

Provenance & Evidence