230-17-1Relevant academic research and scientific papers
Consequent Construction of C-C and C-N Bonds via Palladium-Catalyzed Dual C-H Activation: Synthesis of Benzo[ c]cinnoline Derivatives
Li, Hongsheng,Zhao, Junhao,Yi, Songjian,Hu, Kongzhen,Feng, Pengju
, p. 880 - 889 (2021)
A highly efficient palladium-catalyzed cascade annulation of pyrazolones and aryl iodides to access various benzo[c]cinnoline derivatives has been achieved at 80 °C. A pyridine-type ligand could improve the reaction efficiency under current reaction conditions, giving a higher product yield up to 94%. This novel approach provided a one-pot dual C-H activation strategy with good functional group tolerance, such as halogen, methoxy, nitro, ester, phenol, and so forth. The product could readily convert into cinnoline derivatives.
Well-defined styryl and biphenyl calcium complexes from dilithio compounds and calcium iodide: Synthesis, structure and reactivity toward nitrous oxide
Wei, Baosheng,Zhang, Wen-Xiong,Xi, Zhenfeng
, p. 12540 - 12545 (2018)
Efficient synthesis and structure elucidation of carbon-calcium σ-bonded compounds are of remarkable interest and importance in organometallic chemistry of the heavier s-block metals. In this paper, we report that styryl and biphenyl calcium complexes wit
Cooperative effect of acid sites in the photocyclization of azobenzene within the zeolite microenvironment
Corma, Avelino,García, Hermenegildo,Iborra, Sara,Martí, Vicente,Miranda, Miguel A.,Primo, Jaime
, p. 2177 - 2180 (1993)
Photolysis of azobenzene in the presence of a series of acidic zeolites with different crystal size (0.8 and 0.3 μm), crystalline structure (Y, β, ZSM-5), and framework Si-to-Al ratio (Al/cage ranging from 4.6 to 0.25) gives rise to benzo[c]cinnoline and benzidine. The latter remains protonated within the zeolite cavities, as has been established by FT-IR spectroscopy of the hosts. The lack of influence of the crystallite size on the activity of the zeolite reveals that the reaction is mainly taking place on the internal surface of these microporous solids. Finally, the relationship between the activity of the zeolite and the number of Bro?nsted sites per α-cage indicates that only two H+ per supercavity can participate in the photocyclization of azobenzene. This result agrees with the relative size of the zeolite cavities and the reactant molecules.
Stable Organic Neutral Diradical via Reversible Coordination
Lu, Zhenpin,Quanz, Henrik,Burghaus, Olaf,Hofmann, Jonas,Logemann, Christian,Beeck, Sebastian,Schreiner, Peter R.,Wegner, Hermann A.
, p. 18488 - 18491 (2017)
We report the formation of a stable neutral diboron diradical simply by coordination of an aromatic dinitrogen compound to an ortho-phenyldiborane. This process is reversible upon addition of pyridine. The diradical species is stable above 200 °C. Computations are consistent with an open-shell triplet diradical with a very small open-shell singlet-triplet energy gap that is indicative of the electronic disjointness of the two radical sites. This opens a new way of generating stable radicals with fascinating electronic properties useful for a large variety of applications.
Electrosynthesis of Azobenzenes Directly from Nitrobenzenes
Ma, Yanfeng,Wu, Shanghui,Jiang, Shuxin,Xiao, Fuhong,Deng, Guo-Jun
, p. 3334 - 3338 (2021/10/29)
The electrochemical reduction strategy of nitrobenzenes is developed. The chemistry occurs under ambient conditions. The protocol uses inert electrodes and the solvent, DMSO, plays a dual role as a reducing agent. Its synthetic value has been demonstrated by the highly efficient synthesis of symmetric, unsymmetric and cyclic azo compounds.
Chemoselective electrochemical reduction of nitroarenes with gaseous ammonia
Chang, Liu,Li, Jin,Wu, Na,Cheng, Xu
supporting information, p. 2468 - 2472 (2021/04/02)
Valuable aromatic nitrogen compounds can be synthesized by reduction of nitroarenes. Herein, we report electrochemical reduction of nitroarenes by a protocol that uses inert graphite felt as electrodes and ammonia as a reductant. Depending on the cell voltage and the solvent, the protocol can be used to obtain aromatic azoxy, azo, and hydrazo compounds, as well as aniline derivatives with high chemoselectivities. The protocol can be readily scaled up to >10 g with no decrease in yield, demonstrating its potential synthetic utility. A stepwise cathodic reduction pathway was proposed to account for the generations of products in turn.
Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
supporting information, (2020/02/15)
A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
Cu-Catalyzed tandem: N -arylation of phthalhydrazides with cyclic iodoniums to yield dihydrobenzo [c] cinnolines
Kong, Xiangfei,Li, Shiqing,Lv, Hongxu,Xie, Rongrong,Ye, Xiuqing
, p. 4824 - 4830 (2020/07/13)
Dihydrocinnolines have significant pharmacological properties. Herein, we investigate a Cu-catalyzed tandem N-arylation reaction of phthalhydrazides with cyclic iodonium salts to construct dihydrobenzo[c]cinnoline derivatives. Various iodonium salts, such as symmetrical, unsymmetrical, aryl-aryl, and aryl-heteroaryl ones, could react with phthalhydrazides smoothly and give the title products in moderate to high yields. Moreover, the -NH2 group, which has been diarylated by cyclic iodonium salts to form carbazoles in previous reports, is also well tolerated in this work. This journal is
Metal-free deoxygenation and reductive disilylation of nitroarenes by organosilicon reducing reagents
Bhattacharjee, Argha,Hosoya, Hiromu,Ikeda, Hideaki,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
supporting information, p. 11278 - 11282 (2018/10/20)
A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N’-bis(trime-thylsilyl)-4,4’-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phe-nylhydroxylamine (7a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxy-genation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-gen-erated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C H insertion. In addition, the intramolecular N N coupling reaction proceeded in the reduction of 2,2’-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.
Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex
Powers, Ian G.,Andjaba, John M.,Luo, Xuyi,Mei, Jianguo,Uyeda, Christopher
supporting information, p. 4110 - 4118 (2018/03/29)
Azoarenes are valuable chromophores that have been extensively incorporated as photoswitchable elements in molecular machines and biologically active compounds. Here, we report a catalytic nitrene dimerization reaction that provides access to structurally and electronically diverse azoarenes. The reaction utilizes aryl azides as nitrene precursors and generates only gaseous N2 as a byproduct. By circumventing the use of a stoichiometric redox reagent, a broad range of organic functional groups are tolerated, and common byproducts of current methods are avoided. A catalyst featuring a Ni - Ni bond is found to be uniquely effective relative to those containing only a single Ni center. The mechanistic origins of this nuclearity effect are described.
