Water → 2,3-Dichloro-5-ethenylpyridine

Participants

Reaction Conditions

Reaction Steps

To a solution of the 1-(5,6-dichloro-pyridin-3-yl)-ethanol 15 (311 g. 1.62 mole) in chlorobenzene (3 L) was added p-toluene sulfonic acid (431 g, 2.5 mole) and the reaction mixture was heated at reflux with concomitant removal of water. When the reaction was complete the mixture was concentrated to about 500 mL, diluted with 2 L water, and extracted with 3×1 L ethyl acetate. The organic layer was dried (Na2SO4), concentrated under reduced pressure with low heat, dissolved in 500 mL methylene chloride, and applied to the top of 2 Kg silica column. The purified vinyl pyridine was eluted with a slight gradient of ethyl acetate in hexane, 0% to 10%. 178.55 g, 100% pure 2,3-dichloro-5-vinylpyridine was collected as a clear oil which solidified upon cooling to 4° C. 63% yield. 1H NMR (400 MHz, CDCl3) δ 8.27 (m, 1H), 7.80 (dd, J=12, 18 Hz, 1H), 6.62 (d, J=18 Hz, 1H), 5.46 (d, J=12 Hz, 1H).

Provenance & Evidence