6257-64-3Relevant articles and documents
Manganese Catalyzed Hydrogenation of Azo (N=N) Bonds to Amines
Ben-David, Yehoshoa,Das, Uttam Kumar,Diskin-Posner, Yael,Kar, Sayan,Milstein, David
supporting information, p. 3744 - 3749 (2021/07/09)
We report the first example of homogeneously catalyzed hydrogenation of the N=N bond of azo compounds using a complex of an earth-abundant-metal. The hydrogenation reaction is catalyzed by a manganese pincer complex, proceeds under mild conditions, and yields amines, which makes this methodology a sustainable alternative route for the conversion of azo compounds. A plausible mechanism involving metal-ligand cooperation and hydrazine intermediacy is proposed based on mechanistic studies. (Figure presented.).
Cobalt-Catalyzed Deoxygenative Hydroboration of Nitro Compounds and Applications to One-Pot Synthesis of Aldimines and Amides
Gudun, Kristina A.,Hayrapetyan, Davit,Khalimon, Andrey Y.,Segizbayev, Medet,Slamova, Ainur,Zakarina, Raikhan
, (2021/11/30)
The commercially available and bench-stable Co(acac)2 ligated with bis[(2-diphenylphosphino)phenyl] ether (dpephos) was employed for selective room temperature hydroboration of nitro compounds with HBPin (TOF up to 4615 h?1), tolerating halide, hydroxy, amino, ether, ester, lactone, amide and heteroaromatic functionalities. These reactions offered a direct access to a variety of N-borylamines RN(H)BPin, which were in situ treated with aldehydes and carboxylic acids to produce a series of aldimines and secondary carboxamides without the need for dehydrating and/or coupling reagents. Combination of these transformations in a sequential one-pot manner allowed for direct and selective synthesis of aldimines and secondary carboxamides from readily available and inexpensive nitro compounds.
Synthesis of Azobenzene Dyes Mediated by CotA Laccase
Sousa, Ana Catarina,Baptista, Sara R.,Martins, Lígia O.,Robalo, M. Paula
, p. 187 - 193 (2018/12/04)
An eco-friendly protocol for the synthesis of azobenzene dyes by oxidative coupling of primary aromatic amines is reported. As efficient biocatalytic systems, CotA laccase and CotA laccase/ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) enable the oxidation of various substituted anilines, in aqueous medium, ambient atmosphere and under mild reaction conditions of pH and temperature. A series of azobenzene dyes were prepared in good to excellent yields in an one-pot reaction. A mechanistic proposal for the formation of the azo derivatives is presented. Our strategy offers an alternative approach for the direct synthesis of azobenzene dyes, avoiding the harsh conditions generally required for most of the traditional synthetic methods.
Catalytic Azoarene Synthesis from Aryl Azides Enabled by a Dinuclear Ni Complex
Powers, Ian G.,Andjaba, John M.,Luo, Xuyi,Mei, Jianguo,Uyeda, Christopher
, 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.
Convenient Electrocatalytic Synthesis of Azobenzenes from Nitroaromatic Derivatives Using SmI2
Zhang, Yu-Feng,Mellah, Mohamed
, p. 8480 - 8486 (2017/12/08)
The synthesis of azobenzenes has been a long-standing challenge. Their current preparation at a preparative or industrial scale requires stoichiometric amounts of environmentally unfriendly reactants. Herein, we demonstrate that the catalytic use of electrogenerated samarium diiodide (SmI2) could promote, in one-step synthesis, the reduction of nitrobenzenes into azobenzenes in high yields under mild reaction conditions. This catalytic procedure contains many elements satisfying a sustainable chemical process for the preparation of one of the most widely wanted family of chemical compounds. The easy synthetic procedure, and the absence of precious metals, bases, and nonhazardous substances, already makes our catalytic procedure a serious alternative to currently available methods. This is a promising method for the efficient synthesis of both symmetrical and asymmetrical azo compounds with a high functional group tolerance.
Formal [4+2] cycloaddition of 3-ethoxycyclobutanones with azo compounds
Shima, Yusuke,Matsuo, Jun-ichi
supporting information, p. 4066 - 4069 (2016/08/18)
Azobenzenes reacted with 3-ethoxycyclobutanoes to give 2,3-dihydro-pyridazin-4(1H)-ones by using EtAlCl2as a Lewis acid. Thus, ring cleavage of 3-ethoxycyclobutanones took place to form a zwitterionic intermediate by activation with EtAlCl2, and intermolecular formal [4+2] cycloaddition of the zwitterionic intermediate proceeded with azobenzenes to give 2,3-dihydro-pyridazin-4(1H)-ones after elimination of ethanol. Regioselectivity for cycloaddition of unsymmetrical azobenzenes, ring contraction and chemoselective reduction of 2,3-dihydro-pyridazin-4(1H)-ones, and [4+2] cycloaddition to 4-phenyl-1,2,4-triazolin-3,5-dione are also described.
Mesoporous manganese oxide catalyzed aerobic oxidative coupling of anilines to aromatic azo compounds
Dutta, Biswanath,Biswas, Sourav,Sharma, Vinit,Savage, Nancy Ortins,Alpay, S. Pamir,Suib, Steven L.
supporting information, p. 2171 - 2175 (2016/02/18)
Herein we introduce an environmentally friendly approach to the synthesis of symmetrical and asymmetrical aromatic azo compounds by using air as the sole oxidant under mild reaction conditions in the presence of cost-effective and reusable mesoporous manganese oxide materials.
Solution photochemistry of [ p -(Dimethylamino)phenyl]pentazole (DMAPP) at 193 and 300 nm
Bazanov,Haas
, p. 2661 - 2671 (2015/03/30)
The photochemistry of [p-(dimethylamino)phenyl]pentazole (DMAPP) at 193 nm and in the near UV is reported, with emphasis on the nature of the final stable products. The (dimethylamino)phenyl azide (DMAPA) is found as a major product in MeCN, but not in dichloromethane (DCM). (In this paper the acronyms DMAPP and DMAPA refer to the para isomers.) The photochemistry of DMAPA is also explored for comparison. The data obtained in MeCN solutions are consistent with the initial formation of the corresponding nitrene, but in DCM, different products are found, on the basis of NMR data. In the case of high reactant concentration in DCM (10-2 M), quantitative conversion of DMAPP and DMAPA is observed, indicating a high quantum yield. In contrast, MeCN solutions react much more slowly. A radical-type chain reaction mechanism is proposed to account for this observation. At high dilution, DMAPP is completely converted to products in both solvents. Possible mechanisms accounting for these results are discussed.
One-pot preparation of azobenzenes from nitrobenzenes by the combination of an indium-catalyzed reductive coupling and a subsequent oxidation
Sakai, Norio,Asama, Shun,Anai, Satsuki,Konakahara, Takeo
, p. 2027 - 2033 (2014/03/21)
We demonstrated how a reduction step with a reducing system comprised of In(OTf)3 and Et3SiH and a subsequent oxidation that occurred under an ambient (oxygen) atmosphere allowed the highly selective and catalytic conversion of aromatic nitro compounds into symmetrical or unsymmetrical azobenzene derivatives. This catalytic system displayed a tolerance for the functional groups on a benzene ring: an alkyl group, a halogen, an acetyl group, an ester, a nitrile group, an acetyl group, an ester moiety, and a sulfonamide group.
Thermal stability of p-dimethylaminophenylpentazole
Yang, Yu-Zhang,Li, Yu-Chuan,Zhang, Ru-Bo,Sun, Cheng-Hui,Pang, Si-Ping
, p. 57629 - 57634 (2015/02/05)
The thermal stability of p-dimethylaminophenylpentazole (1) in the solid phase has been thoroughly investigated. The decomposition process of 1 has been verified by a combination of differential scanning calorimetry (DSC), thin-layer chromatography (TLC), temperature-programmed FTIR, and Raman spectroscopy. FTIR and Raman spectra were also calculated to corroborate the results. It was found that 1 could be handled below 20 °C without any obvious deterioration, but it decomposed sharply at 56 °C. The calculated FTIR and Raman vibrational frequencies were in accord with the experimental values.
