[4+1] annulation. This transformation is supposed to proceed by nitrenoid attack onto a lone pair of electrons of the imine nitrogen atom to give the vinylazomethine imine, followed by its 1,5-electrocyclization into pyrazoline and further aromatization into pyrazole. Rare examples of 2-imidoyl-1-phthalimidoaziridines that are formed by competitive [2+1] cycloaddition onto the C=C bond were isolated
N-
氨基邻苯二甲
酰亚胺与 1,2,4-triaryl-1-azabuta-1,3-diene 的氧化加成,在大多数情况下,导致 1,3,5-三芳基
吡唑以中等至良好的产率通过 [4 +1] 年化。这种转化应该是通过类氮烯攻击
亚胺氮原子的一对孤对电子来进行的,得到
乙烯基偶氮甲碱
亚胺,然后将其 1,5-电环化成
吡唑啉并进一步芳构化成
吡唑。对于在
亚胺氮原子上具有缺电子芳基取代基的 1-氮杂二烯,通过在 C=C 键上的竞争性 [2+1] 环加成形成的 2-imidoyl-1-phthalimidoaziridines 的罕见例子以低产率分离。