Tetrahedron

A new and efficient approach to pyrazolines. First synthesis of 3-aryl-5-dichloromethyl-2-pyrazolines

A Guirado, B Martiz, R Andreu, D Bautista

Index: Guirado, Antonio; Martiz, Bruno; Andreu, Raquel; Bautista, Delia Tetrahedron, 2009 , vol. 65, # 31 p. 5958 - 5963

Full Text: HTML

Citation Number: 12

Abstract

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- ...