Thionyl Chloride → 3,4-Dichloro-5-[(2-chloroethyl)sulfanyl]-1-methyl-1H-pyrazole

Participants

Reaction Steps

To a stirred mixture of 48.4 g (0.213 moles) 1-methyl-3,4-dichloro-5-(2-hydroxyethylthio)pyrazole and 50 ml thionyl chloride in 200 ml methylene chloride, about 1 ml pyridine was added. The reaction mixture was heated at reflux for about 12 hours over 2 days time. The solvent was stripped, and the residue was taken up in ether. The etheral solution was washed 5 times with water and then dried over magnesium sulfate. Stripping of the ether gave 52.2 g of the product as a brown-red oil.

Provenance & Evidence