The Reaction of Phenylhydrazine with Sterically Congested Stabilized Phosphorus Ylides in the Presence of Silica Gel Powder in Solvent-Free Conditions: A Novel Synthesis of Fully Substituted Pyrazole Derivatives
作者:Nader Noshiranzadeh、Ali Ramazani
DOI:10.1080/10426500701569448
日期:2008.4.18
Reactions of sterically congested stabilized phosphorus ylides with phenylhydrazine in the presence of silica gel powder in solvent-free conditions proceed smoothly at 100°C to afford dialkyl 2-(3,5-dimethyl-1-phenyl-1H-pyrazol-4-yl)-2-butenedioates in good yields. The structures of the products were deduced from their IR, 1 H NMR, and 13 C NMR spectra. The mass spectra of these compounds displayed molecular
在硅胶粉末存在下,在无溶剂条件下,空间拥挤的稳定磷叶立德与苯肼的反应在 100°C 下顺利进行,得到二烷基 2-(3,5-二甲基-1-苯基-1H-吡唑-4-基) )-2-丁烯二酸酯收率良好。产物的结构由它们的IR、 1 H NMR和13 C NMR光谱推断。这些化合物的质谱在适当的 z 值处显示出分子离子峰。化合物的 1 H NMR (CDCl 3 ) 谱表明每种吡唑存在两种酯异构体(E 和 Z)。E 和 Z 异构体的相对数量是通过它们的 1 H NMR 光谱确定的。该反应具有相当的立体选择性。