[C:1]([C:3]1[CH:4]=[CH:5][C:6]([CH2:9][CH2:10]O)=[N:7][CH:8]=1)#[N:2].O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)(O)[O-].[Na+]>C1(C)C=CC=CC=1>[C:1]([C:3]1[CH:4]=[CH:5][C:6]([CH:9]=[CH2:10])=[N:7][CH:8]=1)#[N:2]A mixture of 0.163 g (1.1 mmol) 5-cyano-2-(2-hydroxyethyl)pyridine and 0.029 g (0.15 mmol) p-toluenesulfonic acid hydrate in 10 mL toluene was heated to reflux for five hours in a flask equipped with a Dean-Stark trap. The cooled mixture was neutralized with 5 mL saturated sodium bicarbonate solution and extracted with ether (3×15 mL). The extract was washed with 3 mL brine, dried over sodium sulfate, and filtered. The filtrate was concentrated to give an oil which was purified by flash chromatography on silica gel elating with 1:3 ethyl acetate:hexane to give 0.052 g (36%) 5-cyano-2-vinylpyridine, mp 29°-30° C.
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