An efficient synthetic method for dichloromethylated pyrazolines has been established. 1- Aryl-4, 4-dichlorobut-3-en-1-ones 4 were efficiently prepared by treatment of acetophenones with anhydrous chloral, followed by dehydration and reductive dechlorination. Compounds 4 reacted with hydrazine hydrate and methylhydrazine to give the respective 5-dichloromethyl- 2-pyrazolines in high to quantitative yields. The molecular structure of 5-dichoromethyl-1- ...
