Expedient synthesis of pyrazoles substituted with amino, hydroxyl and thioamide groups
作者:Boris A. Trofimov、Anastasiya G. Mal’kina、Angela P. Borisova、Valentina V. Nosyreva、Olesya A. Shemyakina、Olga N. Kazheva、Gennadii V. Shilov、Oleg A. Dyachenko
DOI:10.1016/j.tetlet.2008.03.046
日期:2008.5
The reaction of α,β-acetylenic γ-hydroxy nitriles with thiosemicarbazide, under mild conditions (rt, no catalyst, in 1:1 aqueous ethanol, 4–14 h), proceeds chemo-, regio- and stereoselectively to give atypically so far inaccessible tri-functionalized (amino, hydroxyl and thioamide groups) pyrazoles in 53–91% yields. The hydroxyl function is easily protected by using the corresponding acetals of the
在温和的条件下(rt,无催化剂,在1:1乙醇水溶液中,4-14小时),α,β-炔属γ-羟基腈与硫代氨基脲反应,进行化学,区域和立体选择性生成,到目前为止,不典型地发生不可获得的三官能化(氨基,羟基和硫酰胺基)吡唑,产率为53-91%。通过使用起始炔属羟基腈的相应缩醛,可以容易地保护羟基官能团。