Several 3-(2,5-anhydro-ribosyl)-pyrazoles of potential medicinal interest have been synthesized by reacting alkynes or alkynylmagnesium bromides with the p-nitrophenylhydrazone of 2,5-anhydro-ribonyl bromide. From a mechanistic standpoint, it has been shown that the sugar-nitrilimine used in these studies reacts more readily as an electrophile than as a dipole. Thus, the hydrazonyl bromide gave exclusively
通过使
炔烃或炔基
溴化镁与2,5-脱
水-
核糖基
溴的对
硝基苯基hydr反应,已经合成了几种具有潜在医学价值的3-(2,5-脱
水-
核糖基)-
吡唑。从机理的观点来看,已经表明,在这些研究中使用的糖-
硝胺作为亲电子试剂比偶极子更容易反应。因此,当用
苯基乙炔基溴化镁处理时,酰
肼基
溴仅给出相应的苯基
乙炔基hydr,当与
苯乙炔反应时,生成
苯乙炔基hydr和
吡唑的1:1混合物。这证明了在亚
硝胺上的亲核加成比惠斯根的1,3-偶极环加成要快得多。