953-12-8Relevant academic research and scientific papers
Visible-Light-Promoted Diboron-Mediated Transfer Hydrogenation of Azobenzenes to Hydrazobenzenes
Song, Menghui,Zhou, Hongyan,Wang, Ganggang,Ma, Ben,Jiang, Yajing,Yang, Jingya,Huo, Congde,Wang, Xi-Cun
, p. 4804 - 4811 (2021/04/06)
A visible-light-promoted transfer hydrogenation of azobenzenes has been developed. In the presence of B2pin2 and upon visible-light irradiation, the reactions proceeded smoothly in methanol at ambient temperature. The azobenzenes with diverse functional groups have been reduced to the corresponding hydrazobenzenes with a yield of up to 96%. Preliminary mechanistic studies indicated that the hydrogen atom comes from the solvent and the transformation is achieved through a radical pathway.
Hydrogen peroxide based oxidation of hydrazines using HBr catalyst
Du, Wanting,Ma, Zichao,Shao, Liming,Wang, Jian
, (2021/11/18)
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 of the one-pot sequential reactions involving our hydrazine oxidation/hydrolysis/Heck reaction or Cu-catalyzed N-arylation with aryl boronic acid. The distinct advantages of this protocol include metal-free catalysis, waste prevention, and easy operation.
Visible-light-promoted oxidative dehydrogenation of hydrazobenzenes and transfer hydrogenation of azobenzenes
Wang, Xianya,Wang, Xianjin,Xia, Chungu,Wu, Lipeng
supporting information, p. 4189 - 4193 (2019/08/07)
Azo compounds are widely used in the pharmaceutical and chemical industries. Here, we report the use of a non-metal photo-redox catalyst, Eosin Y, to synthesize azo compounds from hydrazine derivatives. The use of visible-light with air as the oxidant makes this process sustainable and practical. Moreover, the visible-light-driven, photo-redox-catalyzed transfer hydrogenation of azobenzenes is compatible with a series of hydrogen donors such as phenyl hydrazine and cyclic amines. Compared with traditional (thermal/transition-metal) methods, our process avoids the issue of over-reduction to aniline, which extends the applicability of photo-redox catalysis and confirms it as a useful tool for synthetic organic chemistry.
Dehydrogenation of the NH?NH Bond Triggered by Potassium tert-Butoxide in Liquid Ammonia
Wang, Lei,Ishida, Akiko,Hashidoko, Yasuyuki,Hashimoto, Makoto
supporting information, p. 870 - 873 (2017/01/14)
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 and its benefit to chemical biology is proved by a novel, convenient, one-pot synthesis of aliphatic diazirines, which are important photoreactive agents for photoaffinity labeling.
A concerted transfer hydrogenolysis: 1,3,2-diazaphospholene-catalyzed hydrogenation of Ni-34;N bond with ammonia-borane
Chong, Che Chang,Hirao, Hajime,Kinjo, Rei
supporting information, p. 3342 - 3346 (2014/04/03)
1,3,2-diazaphospholenes catalyze metal-free transfer hydrogenation of a Ni-34;N double bond using ammonia-borane under mild reaction conditions, thus allowing access to various hydrazine derivatives. Kinetic and computational studies revealed that the rate-determining step involves simultaneous breakage of the B-H and N-H bonds of ammonia-borane. The reaction is therefore viewed as a concerted type of hydrogenolysis. On the double: Diazaphospholenes catalyze the transfer hydrogenation of a Ni-34;N bond under mild reaction conditions, allowing access to various hydrazine derivatives. The catalytic cycle involves two key steps, and the catalyst maintains the PIII oxidation state throughout the catalytic cycle. The reaction mechanism involves a hydrogenolysis of the exocyclic P-N bond of the intermediate by ammonia-borane, and it proceeds in a concerted double-hydrogen-transfer fashion.
Catalytic oxidation of hydrazo derivatives promoted by a TiCl 3/HBr system
Drug, Eyal,Gozin, Michael
, p. 13784 - 13785 (2008/04/11)
Through a novel catalytic process of general synthetic interest, hydrazo compounds were efficiently and selectively converted into corresponding azo derivatives. The proposed mechanism of this process comprises two separate and distinctive catalytic cycle
Pyrazolidinol compounds
-
, (2008/06/13)
The invention provides the use of an optionally hydroxyl-protected 4-hydroxy or hydroperoxy-3,5-dioxopyrazolidine or an equivalent wherein a pyrazolidine ring attached oxygen is replaced by a sulphur, or a physiologically acceptable salt thereof, for the
A Simple and Efficient Method for the Reduction of Azo Compounds
Zhang, Chang-Rui,Wang, Yu-Lu
, p. 4205 - 4208 (2007/10/03)
Reduction of azo compounds using hydrazine hydrate as reducant without catalyst is described, which proceeded smoothly in mild condition and did not pollute the environment.
Reactions of Azoarenes with Tributyltin Hydride
Alberti, Angelo,Bedogni, Nicola,Benaglia, Massimo,Leardini, Rino,Nanni, Daniele,et al.
, p. 607 - 613 (2007/10/02)
Tributyltin hydride when reacted with a series of substituted azoarenes afforded hydrazo compounds with high chemoselectivity and good to high yields.With ortho-substituted azoarenes, mixtures of hydrazo derivatives and N-heterocycles or cyclic products only were obtained.The kinetic law of the process was determined in the presence and in the absence of AIBN; with the radical initiator the reaction proceeds via a radical chain mechanism, whereas without AIBN the presence of stannyl free radicals could be discarded.The mechanism of the noninitiated reaction is discussed.EPR characterization of spin adducts obtained by reacting group IVB organometallic radicals with azo compounds is reported.
