6676-90-0Relevant academic research and scientific papers
TEMPO catalyzed oxidative dehydrogenation of hydrazobenzenes to azobenzenes
Fan, Baomin,Laishram, Ronibala Devi,Li, Jiayan,Luo, Yang,Lv, Haiping,More, Sagar,Su, Zhimin,Xu, Dandan,Yang, Yong,Zhan, Yong
supporting information, p. 3471 - 3474 (2020/05/25)
A metal-free direct oxidative dehydrogenation approach for the synthesis of azobenzenes from hydrazobenzenes has been developed by using TEMPO as an organocatalyst for the first time. The reaction proceeded in open air under mild reaction conditions. A wide range of hydrazobenzenes readily undergo dehydrogenation to give the corresponding azobenzenes in excellent yields.
Photocatalyzed oxidative dehydrogenation of hydrazobenzenes to azobenzenes
Lv, Haiping,Laishram, Ronibala Devi,Li, Jiayan,Zhou, Yongyun,Xu, Dandan,More, Sagar,Dai, Yuze,Fan, Baomin
supporting information, p. 4055 - 4061 (2019/08/07)
Visible light mediated oxidative dehydrogenation of hydrazobenzenes under an ambient atmosphere using an organic dye as a photocatalyst was reported for the first time. The reaction provides an environmentally benign method for the preparation of azobenzenes in excellent yields with good functional group tolerance.
Preparation method of aromatic azo organic compounds
-
Paragraph 0029; 0034; 0037; 0038, (2019/12/25)
The invention discloses a preparation method of aromatic azo compounds so as to achieve high-yield preparation of the azo compounds from diaryl hydrazine low in cost and easy to obtain through oxydehydrogenation by an organic oxidant. According to different raw materials, the symmetrical or asymmetric azo compounds can be obtained, a catalyst is not needed, the reaction raw materials and the organic oxidant are low in cost and easy to obtain, conditions are mild and efficient, a reaction can be complete through only a few minutes, the reaction process is smooth and safe, products are easy to separate, and the preparation method accords with the development concept of green chemistry.
Palladium-catalyzed cyclizative carbonylation of azobenzenes toward 3H-Indazol-3-ones using formic acid as CO source
Gu, Ning,Sun, Song,Cheng, Jiang
supporting information, p. 1069 - 1072 (2018/02/14)
A palladium-catalyzed cyclizative carbonylation of azobenzenes has been developed to access 1-acyl 2-aryl 3H-indazol-3-ones in moderate to good yields with good functional compatibility. This procedure proceeded with the sequential ortho-C–H carbonylation and cyclization, where formic acid served as the CO source. The practicability of this transformation was further increased by the employment of facilely available azobenzenes derivatives as one-handled starting materials.
Aromatic amine oxidation process for preparing aromatic azobenzene method
-
Paragraph 0023-0026, (2017/10/11)
The invention relates to a method for preparing an aromatic azo compound by utilizing aromatic amine oxidation. In the method, air or oxygen serves as an oxygen source, and under the effect of a catalyst, aromatic amine is oxidized into the aromatic azo compound. The method is high in oxidization efficiency and product yield; the air or the oxygen serves as the oxygen source, and the method is economical and environmentally friendly. The product and the catalyst can be separated easily, and the aftertreatment is simple. The catalyst is easy to reuse, and the method has very good application prospect.
Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts
Wang, Min,Ma, Jiping,Yu, Miao,Zhang, Zhe,Wang, Feng
, p. 1940 - 1945 (2016/04/05)
We herein report the transition metal oxide-catalyzed synthesis of azobenzenes through the oxidative coupling of anilines. An octahedral molecular sieve of manganese oxide, OMS-2, exhibited the best activity and selectivity. Nine examples of symmetric azobenzenes and twenty unsymmetric ones were synthesized with 62-99% conversion and 64-99% selectivity. In the aniline cross-coupling reactions, the difference of the Hammett constants of two substituted groups (Δσ) determines the selectivity to unsymmetric azobenzenes, which are the major products at Δσ 0.32. In-depth studies reveal that the surface defect sites of the mixed-valence manganese oxide play a key role in facilitating electron transfer and activating molecular oxygen. The single-electron transfer (SET) reaction mechanism is proposed based on electron paramagnetic resonance and X-ray powder diffraction characterization.
High-Yield Lithiation of Azobenzenes by Tin-Lithium Exchange
Strueben, Jan,Lipfert, Matthias,Springer, Jan-Ole,Gould, Colin A.,Gates, Paul J.,S?nnichsen, Frank D.,Staubitz, Anne
supporting information, p. 11165 - 11173 (2015/11/10)
The lithiation of halogenated azobenzenes by halogen-lithium exchange commonly leads to substantial degradation of the azo group to give hydrazine derivatives besides the desired aryl lithium species. Yields of quenching reactions with electrophiles are therefore low. This work shows that a transmetalation reaction of easily accessible stannylated azobenzenes with methyllithium leads to a near-quantitative lithiation of azobenzenes in para, meta, and ortho positions. To investigate the scope of the reaction, various lithiated azobenzenes were quenched with a variety of electrophiles. Furthermore, mechanistic 119Sn NMR spectroscopic studies on the formation of lithiated azobenzenes are presented. A tin ate complex of the azobenzene was detected and characterized at low temperature.
