Synthesis of Pyrazolyl-2-pyrazolines by Treatment of 3-(3-Aryl-3-oxopropenyl)chromen-4-ones with Hydrazine and Their Oxidation to Bis(pyrazoles)
作者:Albert Lévai、Artur M. S. Silva、Diana C. G. A. Pinto、José A. S. Cavaleiro、Ibon Alkorta、José Elguero、József Jekö
DOI:10.1002/ejoc.200400465
日期:2004.11
The synthesis of several 1-acetyl-3-aryl-5-[3-(2-hydroxyphenyl)pyrazol-4-yl]-2-pyrazolines 3a−3h has been accomplished by treatment of the 3-(3-aryl-3-oxopropenyl)chromen4-ones 1a−h with hydrazine hydrate in hot acetic acid. The 1acetyl-3-aryl-5-(3-chromonyl)-2-pyrazolines 2a−2f were also obtained as by-products. Oxidation of the 1-acetyl-4-pyrazolyl-2-pyrazolines 3a−3f with DDQ gave the 3(5)-aryl