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In this paper, 2,2′-dichlorohydrazobenzene was synthesized by the electrochemical reduction of o-chloronitrobenzene using the ion-exchange membrane method. The effects of different catalysts (litharge, lead tetroxide, and lead nitrate) on the synthesis were investigated. The influence of different catalyst loading approaches on the electrochemical reduction were also examined. The structure and surface morphology of the catalysts were characterized by X-ray diffraction and scanning electron microscopy. Catalyst activity was examined by dynamic potential analyses and cyclic voltammetry. Litharge was found to induce the greatest improvement in the electrolysis reaction rate and also decreases the reaction time. Coating the catalyst on the cathode helps enhance the product yield. The possible reaction mechanism was studied, and the catalyst was found to play a key role in transforming raw substances into intermediates. However, there is little effect on intermediate product transformation into the desired product.

The unprecedented base-initiated generation of a nitrobenzyne and subsequent addition of preformed arylacetonitrile anion nucleophiles is reported. In all cases, 2-amino-5-nitro-3-benzo[b]furans are obtained as major product with small amounts of 3-arylmethyl-2-cyano-4-nitrophenols. A mechanism involving ring closure of phenoxide and nitrile groups of the initial aryne-nitrile anion adduct is proposed to account for the formation of the benzofurans. The three isomeric chloronitrobenzynes, however, do not give aryne products when treated with LDA, but rather are reduced to the corresponding bis-dichloroazoxybenzenes.

Water as a clean solvent and promoter in the organic synthesis have attracted more attention, herein the effect of water was studied for the hydrogenation of o-chloronitrobenzene (o-CNB) over Pt/C and Pd/C catalysts in ethanol, n-heptane and compressed CO2. Very interesting, the reaction rate decreased in ethanol, but increased in n-heptane and compressed CO 2 with the addition of water. The role of water in the reaction was mainly discussed from the experimental data and phase behavior analysis, one is to activate the functional group of NO2 through the interactions via a hydrogen bonding, and the other is to affect the solubility of hydrogen in ethanol and n-heptane. The positive effect of the interaction between water and reactants may be counteracted by the negative effect of hydrogen solubility in ethanol. However, the concentration of o-CNB and hydrogen changed slightly in n-heptane with the addition of water, so the interaction of water with reactants may play a main role in improving the TOF. The combination of H2O and CO2 is more efficient than the pure H2O, CO 2 and H2O-n-heptane systems. The phase behavior may play important role also for the improved activity except for the interactions of H2O and CO2 with the reactants. o-CNB phase was expanded in the compressed CO2 and so the concentration of H2 in o-CNB phase increased due to the miscible of CO2 and H2, resulting in the enhancement of reaction rate and the maximum conversion at pressure of 9 MPa CO2, at which the volume was expanded to the largest one. The similar results were also obtained in the compressed CO 2 system without H2O. In addition, the stability of Pt/C and Pd/C was studied in H2O-n-heptane and H2O-CO 2. As a result, the H2O-CO2 media and Pt/C catalyst is one of the most effective systems for the hydrogenation of o-CNB.

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The hydrogenation of chloronitrobenzene to chloroaniline was investigated over Ni/TiO2 at 35 °C in supercritical CO2 (scCO2), ethanol, and n-hexane. The reaction rate followed the order of scCO2 > n-hexane > eth

A method for reducing a substrate selected from 2-methyl-5-nitropyridine and methyl 4-(2-fluoro-3-nitrobenzyl)piperazine-1-carboxylate is provided catalysed by a nitroreductase and a disproportionation agent.

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.

The invention provides a preparation method of niobium or tantalum complex and an application of the niobium or tantalum complex in catalyzing aromatic amine to generate an oxidized azobenzene compound. The preparation method of the complex comprises A hydration oxide preparation, @timetime@ niobium oxide or tantalum oxide and strong base in 300 - 800 °C melting calcination 2 - 8h, adding water to dissolve and filter, and then adjusting pH through 4-6, suction filtration and drying. The B complex is prepared by mixing a hydrated oxide with a molar ratio 10-25: 1 with hydrogen peroxide, adding an organic acid and a cationic precursor after clarifying the solution, and evaporating and drying to obtain a niobium complex or a tantalum complex. The molar ratio @timetime@: 1-3. In the method for synthesizing the oxidized azobenzene compound by using niobium or tantalum complex as a catalyst, ethanol is used as a solvent, hydrogen peroxide is used as an oxidant, niobium complex or tantalum complex is used as a catalyst, and the addition amount is ppm.

Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.

[A] good workability and safety, cost, and, efficient production of the azoxy benzene azoxy benzene can be produced. [Solution] nitrobenzene ones, having the photocatalytic function with a dye, a reducing agent such as a fluorine resin or a transparent resin material is a mixed solution of 1 mm in diameter are inserted into the tube 4 does not inhibit the reaction, 4 LED lamp 5 emits visible from the outside of the tube moves within the tube 4 is provided with visible light within the tube 4 by a photocatalyst reaction mixed solution so as to obtain azoxy benzene compounds. Figure 2 [drawing] (by machine translation)

A high-yielding and high-rate reduction method that operates with alkenes, alkynes, azides, nitriles, and nitroarenes was developed and optimized. The method makes use of sodium borohydride reduction of CoSO4 under release of hydrogen along with the formation of Co2B as a nanoparticle material. The produced Co2B activates the various functional groups for hydride reduction. The protocol was proven to operate with an assortment of functional groups to provide good to excellent yields. Furthermore, the reduction method was successfully adapted, implemented, and developed for a continuous flow approach using the multi-jet oscillating disk (MJOD) flow reactor platform at atmospheric pressure.

A novel continuous flow method for the methoxylation of chloronitrobenzenes was developed. The reaction went smoothly and high yields were achieved under the optimized conditions. Furthermore, up to 76% yield of azoxybenzenes were obtained from the corresponding nitrobenzenes in the presence of NaOH in continuous flow. Compared to batch conditions, the reaction time was significantly shortened, and the chemical waste was reduced obviously.

The precursor nature effect on the state of the Pd–P surface layer in palladium catalysts and on their properties in the liquid-phase hydrogenation of chloronitrobenzenes under mild conditions has been investigated. A general feature of the Pd–P-containing nanoparticles obtained from different precursors and white phosphorus at P/Pd = 0.3 (PdCl2 precursor) and 0.7 (Pd(acac)2 precursor) is that their surface contains palladium in phosphide form (BE(Pd3d5/2) = 336.2 eV and BE(Р2р) = 128.9 eV) and Pd(0) clusters (BE(Pd3d5/2) = 335.7 eV). Factors having an effect on the chemoselectivity of the palladium catalysts in chloronitrobenzenes hydrogenation are considered, including the formation of small palladium clusters responsible for hydrogenation under mild conditions.

The invention relates to a preparation method for aromatic-azoxybenzene by oxidizing aromatic amine. According to the method, air or oxygen is used as an oxygen source, and aromatic amine is oxidized to be aromatic-azoxybenzene under the effect of metal oxide catalyst. The method has the advantage of high product yield and is easy to separate the catalyst.

An efficient chemoenzymatic process for the synthesis of azoxybenzenes was developed. A peracid was generated in situ by Novozym 435, and then a range of anilines were oxidized by the produced peracid to afford azoxybenzenes in yields ranging from 63.1 to 94.1 %. This method expands the application of lipase in organic synthesis and provides an alternative method for the synthesis of azoxybenzenes.

The azo linkage is a prominent chemical motif which has found numerous applications in materials science, pharmaceuticals, and agrochemicals. Described herein is a sustainable heterogeneous-gold-catalyzed synthesis of azo arenes. Available nitroarenes are deoxygenated and linked selectively by the formation of N-N bonds using molecular H2 without any external additives. As a result of a unique and remarkable synergy between the metal and support, a facile surface-mediated condensation of nitroso and hydroxylamine intermediates is enabled, and the desired transformation proceeds in a highly selective manner under mild reaction conditions. The protocol tolerates a large variety of functional groups and offers a general and versatile method for the environmentally friendly synthesis of symmetric or asymmetric aromatic azo compounds.

Aromatic nitro compounds are reduced via transfer hydrogenation in the presence of palladium on magnesium-lanthanum mixed oxide support in ethanol yielding the corresponding amines. With several acetophenone derivatives, the reduction was accompanied by c

A novel and highly efficient zinc based nanocatalyst has been synthesized by covalent grafting of 2-acetylpyridine on amine functionalized silica@magnetite nanoparticles, followed by metallation with zinc acetate. The resulting nano-composite was found to be highly efficient for oxidation of various aromatic amines to give azoxyarenes. The prepared nanocatalyst was characterized by Electron microscopy techniques (SEM and TEM with EDS), X-ray diffraction (XRD), vibrational sampling magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR) and atomic absorption spectroscopy (AAS) techniques. High turnover number (TON), mild reaction conditions and high selectivity for azoxyarenes with sustained catalytic activity makes present protocol worthy and highly compliant as compared to the other non-magnetic heterogeneous catalytic system. The acquisition of this nanocatalyst is also exemplified by employing the catalyst in leaching and reusability test and the results from the tests showing negligible zinc leaching and recycling was achieved multiple times just by sequestering using an external magnet.

A solvent-free method for the direct oxidation of anilines to the corresponding azo and azoxy homocoupling products by using a planetary ball mill was developed. Various oxidants and grinding auxiliaries were tested and a variety of substituted anilines were investigated. It was possible to form chemoselectively either azo, azoxy, or the nitro compounds from reaction of aromatic anilines. The selectivity of the solvent-free reaction is switchable by applying a combination of oxidant and grinding auxiliary. Furthermore, a comparison with other methods of energy input (microwave, classical heating, and ultrasound) highlighted the advantages of the ball mill approach and its high energy efficiency. Grinding reactions: Highly efficient oxidative homocoupling of aromatic amines was performed under solvent-free conditions in a planetary ball mill (see scheme). The choice of solid oxidants and grinding auxiliaries allowed selective generation of the oxidized products. Other methods of energy input are compared with respect to reaction time and energy consumption.

Azoxy compounds have been prepared in good yields by reductive coupling of aromatic nitro compounds with manganese and a catalytic amount of acetic acid in aqueous conditions. Copyright Taylor & Francis Group, LLC.

The reaction of tetranuclear Pd4(μ-COOCH3) 4(μ-CO)4 cluster (1a) with p- and o- chloronitrosobenzenes was found to give dinuclear nitrosoamide complexes, Pd2(OAc)2(p-ClC6H4N[p-ClC 6H3NO])2 (4) and Pd2(OAc) 2(o-ClC6H4N[o-ClC6H 3NO])2 (5), respectively. The formation of complexes 4 and 5 is accompanied by evolution of CO2, resulting from oxidation of CO coordinated in cluster 1. Complexes 4 and 5 were characterized by elemental analysis and IR and 1H NMR spectroscopy; their structures were studied by EXAFS. The reactions of dinuclear complex 4 with molecular hydrogen and CO were studied. The major products of reduction of 4 with hydrogen include metallic palladium, acetic acid, cyclohexanone, and molecular nitrogen. Treatment of complex 4 with CO under mild conditions (1 atm, 20°C) affords p-chlorophenyl isocyanate.

Aromatic azoxy compounds have been prepared in good yields by the selective reduction of aromatic nitro compounds with Zn/AlCl3 reagent.

A simple and inexpensive procedure for the coupling of nitroarenes to azoxy compounds with bismuth and potassium hydroxide in methanol at ambient temperature is achieved. When carried out under microwave irradiation it gives exclusively azo compounds in excellent yields.

Substituted phenylazo and phenylazoxy compounds were systematically prepared and their anti-androgenic activity was measured in terms of (1) the growth-inhibiting effect on an androgen-dependent cell line, SC-3, and (2) the binding affinity to nuclear androgen receptor. Generally, azo/azoxy compounds showed cell toxicity, and the growth-inhibiting effects on SC-3 cells correlated with the toxicity. However, some compounds, including 4,4'-dinitroazobenzene (25), 4,4'-dimethoxyazobenzene (33), and 2,2'-dichloroazoxybenzene (47), possessed potent anti-androgenic activity without apparent cell toxicity.

Aromatic nitro compounds have been found to be selectively reduced to axoxy compounds in good yields by NaBH4 in the presence of bismuth powder.

In the presence of bismuth(III)chloride-metalllic zinc aromatic nitro compounds have been found to be selectively reduced inter and intramolecularly to the corresponding N-oxides at ambient temperature in high yields.

An activated catalyst prepared from a mixture of nickel nitrate hexahydrate with zinc in dry ethanol under reflux showed exceptional catalytic activity for the reduction of nitroarenes to the corresponding azoxy compounds exclusively in the presence of hydrazine monohydrate.However when nickel nitrate hexahydrate was replaced by nickel chloride dihydrate with zinc, only the aminoarenes were formed in high yields.With unactivated catalyst, the reduction reaction from a mixture of nitroarenes, nickel nitrate or chloride, excess zinc and hydrazine monohydrate gave the corresponding azo, azoxy and amino compounds in much lower yields.

The reaction of ortho-substituted nitrobenzenes with 3 mol vinylmagnesium halides gives mainly 7-substituted indoles together with minor amounts of the aniline from complete reduction of the nitroarene.Under the same experimental conditions, para-substituted nitrobenzenes essentially lead to the corresponding anilines, with indoles being recovered in very low yield.Nitrosoarenes react with 2 mol Grignard reagent to give almost the same product distribution.An accurate analysis of the stoichiometry of the reaction established that in the first stage of the reaction nitroarenes are attacked at the oxygen atoms and are reduced to nitrosoarenes via enolate elimination.The nitroso derivative can undergo a 1,2-addition to give an N-aryl-N-vinylhydroxylamino magnesium salt.Hydrolysis of this intermediate affords hydroxylamine and the carbonyl derivative corresponding to the vinyl Grignard reagent, as proved by the reaction of nitroarenes with 2 mol Grignard reagent.In the presence of an excess of vinyl magnesium halide, a complete reduction to vinylaniline derivatives, which hydrolyse to aniline, occurs.The effect of the bulkiness of the substituent both in the nitroarene and in the Grignard reagent, the orientation of alkylation and the relative reaction rates of indole and aniline formation suggest that indoles arise via a completely different route: i.e. an inverse 1,2-addition to the N=O double bond.The N-aryl-O-vinylhydroxylamino magnesium salt intermediate can undergo a -sigmatropic rearrangement followed by a rapid ring closure.The third mole of Grignard reagent acts as a base on this bicyclic intermediate, re-aromatizing the six-membered ring.Elimination of water ultimately leads to the indole.

The study of the reactivity of monohalonitrobenzenes in 2-propanol solutions of potassium 2-propoxide has led to the identification of three distinct reaction paths: (a) hydro dehalogenation to nitrobenzene, (b) alkoxy dehalogenation via the SNAr mechanism, and (c) nitro reduction to azoxy and anilino derivatives via nitroso intermediates.With the exception of 2- and 4-fluoronitrobenzene, radical processes c or a are faster than the SNAr reaction.The radical processes proceed via a common intermediate, the radical anion *-, which can undergo unimolecular fragmentation to nitroaryl radical and X- (path a, favored for X = 2-I, 2-Br), or reduction to the dianion 2-, the direct precursor of the nitroso intermediate XC6H4NO (path c).In the presence of oxyen, an effective oxidant of the radical-anion intermediate, the SNAr reaction prevails for the activated ortho and para substrates.Cation-anion interactions are also major consequence in determining the course of reaction.Ion pairing favors nitro reduction, whereas it slows both the SNAr and the hydro dehalogenation reactions.

Trialkylstibines can reduce nitroarenes to azoxy compounds, quinone to hydroquinone, and p-toluenesulfonyl chloride to p-toluenesulfinic acid in good yields under mild conditions.Debromination of α-bromophenylacetonitrile or 1,2-dibromo-1-phenylethane by tri-n-butylstibine gives 2,3-diphenylsuccinonitrile or styrene, respectively.

Various nitro compounds were effectively reduced by sodium hydrogen telluride in good yields.Thus, reductive conversion of unhindered nitrobenzenes to azoxybenzenes, sterically hindered nitrobenzenes to anilines, nitroalkanes to dimer of nitrosoalkanes, and vicinal-dinitroalkane to olefin was achieved.