7250-68-2Relevant articles and documents
Oxidative dehydrogenation of hydrazines and diarylamines using a polyoxomolybdate-based iron catalyst
Huang, Lei,Qiu, Shiqin,Wei, Yongge,Xie, Jingyan,Yu, Han,Zeng, Xianghua,Zhao, Weizhe
supporting information, p. 7677 - 7680 (2021/08/09)
We report an efficient method for the oxidative dehydrogenation of hydrazines and diarylamines in aqueous ethanol using Anderson-type polyoxomolybdate-based iron(iii) as a catalyst and hydrogen peroxide as an oxidant. A series of azo compounds and tetraarylhydrazines were obtained in moderate to excellent yields. The reaction conditions and substrate scopes are complementary or superior to those of more established protocols. In addition, the catalyst shows good stability and reusability in water. The preliminary mechanistic studies suggest that a radical process is involved in the reaction.
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.
Anion recognition in aqueous solution by cyclic dinuclear square cage-shaped coordination complexes
Fu, Cai-Ye,Li, Yu-Qian,Chen, Lu,Wang, Yun-Guang,Lin, Li-Rong
supporting information, (2019/07/02)
Three cyclic dinuclear complexes, namely [M2(H2L)2](ClO4)4 [M = Co2+ (1), Ni2+ (2), Zn2+ (3), H2L = (1,2)-bis-N'-(pyridin-2-ylmethylene)benzohydrazide hydrazine, C26H22N8O2], containing amide and hydrazine groups were synthesized and characterized. Each central metal ion is coordinated with two oxygen atoms and four nitrogen atoms from carbonyl, and pyridine and imine, respectively. The metal ion is six-coordinated and has a slightly deformed octahedral geometry. X-ray crystallographic analyses showed that all the three cyclic dinuclear complexes crystallize in the orthorhombic system, and belong to the C222 space group, with two molecules in each unit cell. The cyclic dinuclear molecule is linked by two H2L ligands with a Z-form-HN-NH-bridge, nearly forming a square coordination cage with edges of length around 8.4 ?. The cyclic dinuclear complexes can recognize acetate and fluoride anions in an acetonitrile solution containing 60% volume water. Recognition is governed by electrostatic interactions in cooperation with the cage structure effect with the mechanism of anion displacement reaction. The results show that the recognition of anions in acetonitrile aqueous solution is an exothermic and entropy-reducing reaction. This suggests that the enthalpy change plays an important role in the presence of highly polar water and highlights the importance of positively charged cage structure effect. A color change from light yellow to dark yellow was clearly observed for complex 3 on addition of acetate or fluoride anions in acetonitrile aqueous solution containing 60% water. Complex 3 can be used for colorimetric “naked eye” recognition of acetate or fluoride anions in acetonitrile aqueous solution. Theoretical calculations based on time dependent density functional theory (TD-DFT) show the agreement between the theoretical results and experimental data.
Synthesis of 2 - fluoro aniline compounds of the method
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Paragraph 0122; 0124, (2019/05/15)
The invention discloses a method for synthesizing 2 - fluoro aniline compounds of the method, the method is: shown in formula Ia aniline compound of formula Ib α and β shown aniline compound as raw materials, through coupling reaction shown [...] azobenzene compound II, then the type II shown azobenzene compound with a palladium catalyst, fluorination reagent, additive, organic solvent, in the 30 - 150 °C temperature closed agitating the fluorination reaction, [...] compound of formula III, type III compounds are shown in the reaction under the action of a reducing [...] shown IV 2 - fluoro aniline compounds; this invention synthetic 2 - fluoro aniline compounds substrate wide adaptability, mild reaction conditions, the operation is simple, fluorinated and good selectivity, [...] aniline compounds is prepared by many drug molecule is an important intermediate and starting material, wide application prospects.
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.
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.
Electrocatalytic Z → E Isomerization of Azobenzenes
Goulet-Hanssens, Alexis,Utecht, Manuel,Mutruc, Dragos,Titov, Evgenii,Schwarz, Jutta,Grubert, Lutz,Bléger, David,Saalfrank, Peter,Hecht, Stefan
supporting information, p. 335 - 341 (2017/05/16)
A variety of azobenzenes were synthesized to study the behavior of their E and Z isomers upon electrochemical reduction. Our results show that the radical anion of the Z isomer is able to rapidly isomerize to the corresponding E configured counterpart with a dramatically enhanced rate as compared to the neutral species. Due to a subsequent electron transfer from the formed E radical anion to the neutral Z starting material the overall transformation is catalytic in electrons; i.e., a substoichiometric amount of reduced species can isomerize the entire mixture. This pathway greatly increases the efficiency of (photo) switching while also allowing one to reach photostationary state compositions that are not restricted to the spectral separation of the individual azobenzene isomers and their quantum yields. In addition, activating this radical isomerization pathway with photoelectron transfer agents allows us to override the intrinsic properties of an azobenzene species by triggering the reverse isomerization direction (Z → E) by the same wavelength of light, which normally triggers E → Z isomerization. The behavior we report appears to be general, implying that the metastable isomer of a photoswitch can be isomerized to the more stable one catalytically upon reduction, permitting the optimization of azobenzene switching in new as well as indirect ways.
Stabilisation of gold nanoparticles by N-heterocyclic thiones
Moraes, Leonardo C.,Lacroix, Bertrand,Figueiredo, Rute C.,Lara, Patricia,Rojo, Javier,Conejero, Salvador
supporting information, p. 8367 - 8371 (2017/07/12)
Gold nanoparticles (Au-NPs) have been prepared using N-heterocyclic thiones (NHTs) as ligand stabilisers. These Au-NPs have been shown to be very stable, even in air, and have been characterized by a combination of several techniques (TEM, HR-TEM, STEM-HAADF, EDX, DLS, elemental analysis and 1H NMR). These nanoparticles are active in the catalytic reduction of nitroarenes to anilines.
Synthesis of Azobenzenes Using N-Chlorosuccinimide and 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)
Antoine John, Alford,Lin, Qing
, p. 9873 - 9876 (2017/09/23)
A convenient method for the synthesis of symmetrical azobenzenes is reported. This one-step procedure involves treatment of anilines with N-chlorosuccinimide (NCS) and organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). A wide range of commercially available substituted anilines readily participate in this reaction to produce the corresponding azobenzenes in moderate-to-excellent yields in minutes.
First use of p-tert-butylcalix[4]arene-tetra-O-acetate as a nanoreactor having tunable selectivity towards cross azo-compounds by trapping silver ions
Sarkar, Piyali,Mukhopadhyay, Chhanda
supporting information, p. 442 - 451 (2016/01/30)
p-tert-Butylcalix[4]arene-tetra-O-acetate was established for the first time as a member of the nanoreactor series, even without having any -OH group. The nano range distribution of this nanoreactor was ascertained by DLS, SEM and TEM studies. The capability of this cavitand towards hosting amines in a competitive manner generates a new green pathway for cross coupling of aromatic amines to give the corresponding azo-compounds. In this context, using p-tert-butylcalix[4]arene-tetra-O-acetate as a nanoreactor and silver nitrate as a catalyst, we got the cross azo-compound in good to excellent yields in the eco-friendly solvent water. This green methodology is also applicable for the synthesis of respective homo-compounds.
