我们报告了一种使用安德森型多氧钼酸铁 ( III ) 作为催化剂和过氧化氢作为氧化剂在乙醇水溶液中氧化脱氢肼和二芳基胺的有效方法。以中等至极好的收率获得了一系列偶氮化合物和四芳基肼。反应条件和底物范围补充或优于更成熟的方案。此外,该催化剂在水中表现出良好的稳定性和重复使用性。初步的机理研究表明,该反应涉及一个自由基过程。
Hydrogen peroxide based oxidation of hydrazines using HBr catalyst
作者:Jian Wang、Zichao Ma、Wanting Du、Liming Shao
DOI:10.1016/j.tet.2021.132546
日期:2021.12
Azo compounds (RN = NR′) are an important class of organic molecules that find wide application in organic synthesis. Herein, we report an efficient, practical and metal-free oxidation of hydrazines (RNH-NHR’) to azo compounds using 5 mol% HBr and hydrogen peroxide as terminal oxidant. This new method has been demonstrated by 40 examples with excellent yields. In addition, we showcased two examples
A novel strategy for the dehydrogenation of the NH−NH bond is disclosed using potassium tert‐butoxide (tBuOK) in liquid ammonia (NH3) under air at room temperature. Its synthetic value is well demonstrated by the highly efficient synthesis of aromatic azo compounds (up to 100 % yield, 3 min), heterocyclic azo compounds, and dehydrazination of phenylhydrazine. The broad application of this strategy
A highly efficient, metal-free, chemical oxidation of hydrazines has been implemented using environmentally friendly TCCA as oxidant. This benign protocol provides straightforward access to a wide range of azo compounds in THF in excellent yield. Altogether, 35 azo compounds were obtained in this way and scale-up preparations were performed. Additionally, a plausible mechanism was also proposed. Step-economical
Electrochemical dehydrogenation of hydrazines to azo compounds
作者:Ke-Si Du、Jing-Mei Huang
DOI:10.1039/c9gc00515c
日期:——
A strategy for the electrochemical dehydrogenation of hydrazine compounds is disclosed under ambient conditions. This protocol proceeded smoothly in ethanol by employing electrons as clean oxidants. Its synthetic value is well demonstrated by the highly efficient synthesis of symmetric and unsymmetric azo compounds. It is an environmentally friendly transformation and the present protocol was effective