Water → 2,3-Dichloro-5-ethenylpyridine

HRID 1942264Notes

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]([CH:9](O)[CH3:10])[CH:5]=[N:6][C:7]=1[Cl:8].C1(C)C=CC(S(O)(=O)=O)=CC=1.O>ClC1C=CC=CC=1>[Cl:8][C:7]1[C:2]([Cl:1])=[CH:3][C:4]([CH:9]=[CH2:10])=[CH:5][N:6]=1

Participants

Conditions

Temperature: 4 °C

Procedure

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).

Workup

temperaturethe reaction mixture was heated
concentrationwas concentrated to about 500 mL
additiondiluted with 2 L water
extractionextracted with 3×1 L ethyl acetate
dry with materialThe organic layer was dried (Na2SO4)
concentrationconcentrated under reduced pressure with low heat
dissolutiondissolved in 500 mL methylene chloride
washThe purified vinyl pyridine was eluted with a slight gradient of ethyl acetate in hexane, 0% to 10%
custom178.55 g, 100% pure 2,3-dichloro-5-vinylpyridine was collected as a clear oil which

Sources & evidence

ORD record: ord-f577053e1eb74d39a5e6730c55567031
Source dataset: uspto-grants-2013_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08389549B2

Reaction notes

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