15426-14-9Relevant academic research and scientific papers
Single crystal MnOOH nanotubes for selective oxidative coupling of anilines to aromatic azo compounds
Zou, Yong,Zhang, Mingkai,Cao, Fangxian,Li, Jiayuan,Zhang, Sai,Qu, Yongquan
supporting information, p. 19692 - 19697 (2021/09/20)
Catalytic synthesis of aromatic azo compounds by oxidative coupling of anilines using molecular oxygen represents a facile, green and valuable process; however, such an economical process suffers from poor catalytic activity and selectivity. Herein, novel single crystal MnOOH nanotubes with abundant Mn3+sites and high oxygen defects were successfully synthesized. The catalyst exhibited high selectivity for oxidative coupling of anilines, achieving complete transformation into aromatic azo compounds under mild conditions, even at room temperature.
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.
Synthesis of novel 1,2-diarylpyrazolidin-3-one–based compounds and their evaluation as broad spectrum antibacterial agents
Abadi, Ashraf H.,Abdel-Halim, Mohammad,El-Sharkawy, Lina Y.,Engel, Matthias,Fathalla, Reem K.,Mokbel, Salma A.
, (2020/03/30)
There is a continuous need to develop new antibacterial agents with non-traditional mechanisms to combat the nonstop emerging resistance to most of the antibiotics used in clinical settings. We identified novel pyrazolidinone derivatives as antibacterial hits in an in-house library screening and synthesized several derivatives in order to improve the potency and increase the polarity of the discovered hit compounds. The oxime derivative 24 exhibited promising antibacterial activity against E. coli TolC, B. subtilis and S. aureus with MIC values of 4, 10 and 20 μg/mL, respectively. The new lead compound 24 was found to exhibit a weak dual inhibitory activity against both the E. coli MurA and MurB enzymes with IC50 values of 88.1 and 79.5 μM, respectively, which could partially explain its antibacterial effect. A comparison with the previously reported, structurally related pyrazolidinediones suggested that the oxime functionality at position 4 enhanced the activity against MurA and recovered the activity against the MurB enzyme. Compound 24 can serve as a lead for further development of novel and safe antibiotics with potential broad spectrum activity.
Selective Propargylation of Diaryl Azo Compounds Using Metallic Barium
Yanagisawa, Akira,Heima, Toshihiko,Watanabe, Kana,Haeno, Shun
supporting information, p. 1817 - 1822 (2020/09/02)
The Barbier-type propargylation of azo compounds with α,γ-disubstituted propargylic tosylates was achieved by using metallic barium as the promoter. Various propargylated hydrazines (α-adducts) were exclusively synthesized from the corresponding propargylic tosylates and azobenzenes (diaryldiazenes). The thus-obtained propargylic hydrazines were further efficiently converted into propargylic amines by reductive N-N bond cleavage. Benzidine rearrangement of the propargylic hydrazines was also attempted.
Nitrate promoted mild and versatile Pd-catalysed C(sp2)-H oxidation with carboxylic acids
Hao, Hong-Yan,He, Yu-Ting,Lou, Shao-Jie,Luo, Gen,Mao, Yang-Jie,Xiong, Xue,Xu, Dan-Qian,Xu, Zhen-Yuan
supporting information, p. 6732 - 6737 (2020/09/21)
A nitrate-promoted Pd-catalysed mild cross-dehydrogenative C(sp2)-H bond oxidation of oximes or azobenzenes with diverse carboxylic acids has been developed. In contrast to the previous catalytic systems, this protocol features mild conditions (close to room temperature for most cases) and a broad substrate scope (up to 64 examples), thus constituting a versatile method to directly prepare diverse O-aryl esters. Moreover, the superiority of the nitrate additive in this mild transformation was further determined by experimental and computational evidence.
Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives
Moran, Maria Jesus,Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Manzoli, Maela,Cravotto, Giancarlo
supporting information, p. 2689 - 2700 (2020/05/18)
A highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene. Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield. (Figure presented.).
Trichloroisocyanuric Acid Mediated Oxidative Dehydrogenation of Hydrazines: A Practical Chemical Oxidation to Access Azo Compounds
Cao, Guiyan,Hu, Yulai,Huang, Danfeng,Huo, Congde,Liu, Xuan,Su, Yingpeng,Wang, Ke-Hu,Yu, Jie,Zhang, Rong,Zhao, Yanan
supporting information, p. 1103 - 1112 (2020/04/01)
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 process, mild reaction conditions, operational simplicity, high reaction efficiency, and easy scale-up highlight the practicality of this methodology.
Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
Karunakaran,Venkataramanan
, p. 375 - 385 (2019/02/14)
Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
Method for catalytically synthesizing azobenzene compound through double-metal composite oxide
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Paragraph 0042; 0043, (2019/03/08)
The invention discloses a method for catalytically synthesizing an azobenzene compound through a double-metal composite oxide and belongs to the technical field of catalytic synthesis of azobenzene. According to the method disclosed by the invention, under the action of the double-metal composite oxide, air or oxygen is used as an oxidant, so that amines containing different substituent groups aredirectly oxidized and coupled under a moderate condition to synthesize the azobenzene compound. A catalysis system adopted by the method has moderate reaction conditions and high selectivity; the synthesis of the azobenzene compound can be efficiently catalyzed by carrying out reacting at 60 DEG C and in the air; transition metal which is cheap and easy to obtain and contains iron, cobalt, nickel, aluminum, manganese and copper is used as the double-metal composite oxide, so that the availability of a double-metal composite oxide catalyst is improved.
Rhodium-Catalyzed Reaction of Azobenzenes and Nitrosoarenes toward Phenazines
Xiao, Yan,Wu, Xiaopeng,Wang, Hepan,Sun, Song,Yu, Jin-Tao,Cheng, Jiang
supporting information, p. 2565 - 2568 (2019/04/30)
A rhodium-catalyzed annulative reaction between azobenzenes and nitrosoarenes has been developed, leading to a series of phenazines in moderate to good yields. This procedure proceeds with sequential chelation-assisted addition of aryl C-H to nitrosoarenes and ring closure by electrophilic attack of azo group to aryl. During this transformation, the azo group served as not only a traceless directing group but also a building block in the final products.
