Tin(II) chloride selectively reduces the aromatic nitro group to the amino group, the azoxy group remaining intact. This allows the preparation of 2-(R-NNO-azoxy)anilines from 2-(R-NNO-azoxy)nitrobenzenes bearing electron-donating or weak electron-withdrawing substituents (Me or Br) in the benzene ring and alkyl substituents at the distal N atom of the azoxy group. The presence of electron-withdrawing substituents at the azoxy group (for example, CO2Et) leads to a change in the direction of the reaction resulting in selective reduction of the azoxy group to the hydrazo group.
Molybdenum-catalyzed deoxygenative heterocyclization of 2-nitroazobenzenes: a novel strategy for catalytic synthesis of 2-aryl-2<i>H</i>-benzo[<i>d</i>][1,2,3]triazoles
A novel strategy for the catalytic synthesis of 2-aryl-2H-benzo[d][1,2,3]triazoles bearing a wide range of functional groups in good to excellent yields by non-noble molybdenum-catalyzed deoxygenative heterocyclization of 2-nitroazobenzenes is described. The salient features of the transformation include the use of readily available substrates, valuable products and ease of scale-up. The mechanistic
一种通过非贵重钼催化的2的脱氧杂环化催化合成具有多种官能团的2-芳基-2H-苯并[ d ][1,2,3]三唑的新策略,收率良好至优异描述了-硝基偶氮苯。该转化的显着特点包括使用现成的底物、有价值的产品和易于扩大规模。机理研究表明该反应是通过Mo( VI )/Mo( IV )催化循环从2-硝基偶氮苯进行双重脱氧,形成2-芳基-2H-苯并[ d ][1,2,3 ]三唑-N 1 -氧化物或氮烯中间体。