Substitution of a nitro group by diazonium salts in σH-Adducts of carbanions to mono-nitrobenzenes. Formation of substituted azobenzenes and indazoles
作者:Zbigniew Wróbel、Bogdan Wilk、Andrzej Kwast
DOI:10.1016/j.tet.2021.132186
日期:2021.6
the nitro group. The so-formed intermediates eliminate HNO2 molecule under action of base, yielding substituted azobenzenes. Adducts of secondary carbanions, stabilized by cyano or sulfonyl groups to the ortho positions of nitrobenzenes, cyclize in situ to substituted indazoles. Some ortho σH-adducts of 1-chloroethyl phenyl sulfone carbanion add diazonium cations at meta position to the nitro group
σ ħ在从被氰基,烷氧基羰基或磺酰基稳定化的硝基苯衍生物与碳负离子低温下形成-Adducts与苯重氮盐作为亲核试剂反应,在碳原子带有硝基优先形成一个新的CN键。如此形成的中间体在碱的作用下消除了HNO 2分子,产生了取代的偶氮苯。通过氰基或磺酰基稳定在硝基苯邻位的仲碳负离子的加合物在原位环化成取代的吲唑。一些邻σ ħ的-adducts 1-氯乙基苯基砜的碳负离子在添加重氮阳离子的元硝基位置。在这种情况下,随后的HCl消除导致偶氮化合物将硝基保留在其原始位置。