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
几种 1-乙酰基-3-芳基-5-[3-(2-羟基苯基)吡唑-4-基]-2-吡唑啉3a-3h的合成已通过处理3-(3-芳基-3 -oxopropenyl)chromen4-ones 1a-h 与水合肼在热乙酸中。1乙酰基-3-芳基-5-(3-色酮基)-2-吡唑啉2a-2f也作为副产物获得。用 DDQ 氧化 1-乙酰基-4-吡唑基-2-吡唑啉 3a-3f 得到 3(5)-芳基-5(3)-[3(2-羟基苯基)吡唑-4-基]吡唑 5a-5f . 2-吡唑啉环的氧化伴随着N-脱酰化。讨论了两种转化的反应机制,第一个得到了实验研究的支持