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A nitrogen-doped carbon supported Co/Ni bimetallic catalyst 2wt%Co/Ni@NC-700-10 was prepared and found to be efficient in the reductive N-formylation of 2,4-diamino-5-nitroso-6-hydroxypyrimidine (DANHP) to 2,4-diamino-5-formyl-6-hydroxypyrimidine (DAFHP) for the synthesis of guanine. Under optimal conditions, the conversion of DANHP reached up to 95.6% with a DAFHP selectivity of 97.6%. The characterization results revealed that the cobalt/nickel nanoparticles of the catalyst uniformly dispersed and encapsulated in the nitrogen-dopped carbon, and the catalyst has the characters of large surface area, as well as uniform dispersion and small diameters of metal nanoparticles in the form of Co/Ni alloy, which endowed its good catalytic performance in the reaction.

A Rh(III)-catalyzed C-H arylation reaction of N-nitrosoanilines has been developed in which arylboronic acids were used as arylation reagents. It provides an efficient strategy for the synthesis of N-nitroso-[1,1'-biphenyl]-2-amine, which is an important starting material for the synthesis of N-hetero biaryl compounds, such as 2-amine-1,1'-biphenyl, carbazole, phenanthridone. This protocol can be applied to various N-alkyl substituted N-nitrosoanilines and N-nitrosoanilines with substituents on the phenyl ring. Arylboronic acids with both electron-donating and electron-withdrawing groups are tolerated.

C25H39N2O3PRh, triclinic, P21/n (no. 14), a = 13.505(5) Å, b = 14.266(5) Å, c = 13.405(4) Å, β = 91.280(3)°, V = 2574.8(15) Å3, Z = 4, R gt (F) = 0.0399, wR ref (F 2) = 0.1026, T = 100 K.

α-Diimines are commonly used as supporting ligands for a variety of transition metal-catalyzed processes, most notably in α-olefin polymerization. They are also precursors to valuable synthetic targets, such as chiral 1,2-diamines. Their synthesis is usually performed through acid-catalyzed condensation of amines with α-diketones. Despite the simplicity of this approach, accessing unsymmetrical α-diimines is challenging. Herein, we report the Ti-mediated intermolecular diimination of alkynes to afford a variety of symmetrical and unsymmetrical α-diimines through the reaction of diazatitanacyclohexadiene intermediates with C-nitrosos. These diazatitanacycles can be readily accessed in situ via the multicomponent coupling of Ti≡NR imidos with alkynes and nitriles. The formation of α-diimines is achieved through formal [4+2]-cycloaddition of the C-nitroso to the Ti and γ- carbon of the diazatitanacyclohexadiene followed by two subsequent cycloreversion steps to eliminate nitrile and afford the α- diimine and a Ti oxo.

A reaction of nitric acid with [RuNO(Py)2(NO2)2OH] without heating is shown to result in the complete substitution of nitro and hydroxo ligands with the formation of [RuNO(Py)2(NO3)3] (1). The high lability of nitrate ligands allows their subsequent substitution with the formation of [RuNO(Py)3(NO3)(OH)](NO3) complex (2). The compounds are characterized by the elemental analysis and IR spectroscopy. Their crystal structures are determined by X-ray crystallography. The crystallographic data for complex 1 are: a = 8.9174(4) A, b = 12.2822(5) A, c = 15.9104(6) A, β = 94.4160(10)°, space group P21/c, Z = 4, R = 0.0468 [I > 2σ(I)]; for complex 2: a = 10.8147(4) A, b = 12.6004(5) A, c = 14.2201(5) A, β = 101.5750(10)°, space group Cc, Z = 4, R = 0.0174. Complex 1 is obtained as a facial isomer. Oxygen atoms of coordinated nitrate ligands occupy one of the faces of a distorted RuN3O3 octahedron. In complex 2, the hydroxo ligand is coordinated in the trans-position to the nitroso group. The equatorial positions in the octahedral ruthenium environment are occupied by three nitrogen atoms of pyridine ligands and the oxygen atom of the nitrate ligand.

A novel copper-catalyzed [3 + 2] cycloaddition reaction of alkynes with nitrile oxides generated in situ from the coupling reaction of copper carbene and nitroso radical has been developed. The thr...

An enantioselective primary amine-catalyzed total N-selective nitroso aldol reaction (N-NA) was achieved through the oxidation of primary aromatic amines to the corresponding nitrosoarenes catalyzed by selenium reagents and 30% H2O2. This protocol provides a facile and highly efficient access to α-hydroxyamino carbonyls bearing chiral quaternary centers under exceedingly mild and green reaction conditions with high chemo- and enantiocontrol.

A novel voltammetric sensor for the determination of p-nitrophenol has been developed using carbon paste electrode (CPE) modified by metallic palladium (Pd) supported onto natural phosphate (NP). T...

The UV/monochloramine (NH2Cl) process is an emerging advanced oxidation process (AOP) in water treatment via radicals produced from the UV photolysis of NH2Cl. This study investigated the degradation of micropollutants by the UV/NH2Cl AOP, with ibuprofen (IBP) and naproxen (NPX) selected as representative micropollutants. Hydroxyl radical (HO•) and chlorine atom (Cl•) were identified in the process, and unexpectedly, we found that reactive nitrogen species (RNS) also played important roles in the transformation of micropollutants. The electron paramagnetic resonance (EPR) analysis proved the production of •NO as well as HO•. The concentrations of HO•, Cl•, and •NO in UV/NH2Cl remained constant at pH 6.0-8.6, resulting in the slightly changed UV fluence-based pseudo-first-order rate constants (k') of IBP and NPX, which were about 1.65 × 10-3 and 2.54 × 10-3 cm2/mJ, respectively. For IBP, the relative contribution of RNS to k' was 27.8% at pH 7 and 50 μM NH2Cl, which was higher than that of Cl• (6.5%) but lower than that of HO• (58.7%). For NPX, the relative contribution of RNS to k' was 13.6%, which was lower than both Cl• (23.2%) and HO• (46.9%). The concentrations of HO•, Cl•, and •NO increased with the increasing NH2Cl dosage. Water matrix components of natural organic matter (NOM) and bicarbonate can scavenge HO•, Cl•, and RNS. The presence of 5 mg/L NOM decreased the k' of IBP and NPX by 66.9 and 57.6%, respectively, while 2 mM bicarbonate decreased the k' of IBP by 57.4% but increased the k' of NPX by 10.5% due to the contribution of CO3•- to NPX degradation. Products containing nitroso-, hydroxyl-, and chlorine-groups were detected during the degradation of IBP and NPX by UV/NH2Cl, indicating the role of nitrogen oxide radical (•NO) as well as HO• and Cl•. Trichloronitromethane formation was strongly enhanced in the UV/NH2Cl-treated samples, further indicating the important roles of RNS in this process. This study first demonstrates the involvement of RNS in the transformation of micropollutants in UV/NH2Cl.

Soluble nitrosoguanidine- and N-methylnitrosoguanidine-based metallotriazole complexes of ruthenium(II) monocarbonyls have been prepared and characterized. Both nitrosoguanidines prove to be strong chelates with the formally π-accepting nitroso nitrogen binding cis to carbon monoxide and a π-donating amide trans to the CO. The resulting ensemble consists of ruthenium examples of 1-metallo-2,3,5-triazoles. The ruthenium coordination sphere is completed by anions, either H-, Cl-, or Ph-, trans to the nitroso group as well as two mutually trans PPh3 groups. The π-donating amide group is formally sp2 hybridized with a planar nitrogen to give a strongly bound five-membered chelating anion. Together, these results illustrate the remarkable potential for the nitrosoguanidinates as a family of new metal chelates.

Permanganate (Mn(VII)) has been widely studied for removal of emerging organic contaminants (EOCs) in water treatment and in situ chemical oxidation process. Studies on the reactive intermediate manganese products (e.g., Mn(III) and manganese dioxide (MnO2)) generated from Mn(VII) reduction by EOCs in recent decades shed new light on Mn(VII) oxidation process. The present work summarizes the latest research findings on Mn(VII) reactions with a wide range of EOCs (including phenols, olefins, and amines) in detailed aspects of reaction kinetics, oxidation products, and toxicity changes, along with special emphasis on the impacts of intermediate manganese products (mainly Mn(III) and MnO2) in-situ formed. Mn(VII) shows appreciable reactivities towards EOCs with apparent second-order rate constants (kapp) generally decrease in the order of olefins (kapp = 0.3 - 2.1 × 104 M−1s−1) > phenols (kapp = 0.03 - 460 M−1s−1) > amines (kapp = 3.5 × 10−3 - 305.3 M−1s−1) at neutral pH. Phenolic benzene ring (for phenols), (conjugated) double bond (for olefins), primary amine group and the N-containing heterocyclic ring (for amines) are the most reactive sites towards Mn(VII) oxidation, leading to the formation of products with different structures (e.g., hydroxylated, aldehyde, carbonyl, quinone-like, polymeric, ring-opening, nitroso/nitro and C-N cleavage products). Destruction of functional groups of EOCs (e.g., benzene ring, (conjugated) double bond, and N-containing heterocyclic) by Mn(VII) tends to decrease solution toxicity, while oxidation products with higher toxicity than parent EOCs (e.g., quinone-like products in the case of phenolic EOCs) are sometimes formed. Mn(III) stabilized by model or unknown ligands remarkably accelerates phenolic EOCs oxidation by Mn(VII) under acidic to neutral conditions, while MnO2 enhances the oxidation efficiency of phenolic and amine EOCs by Mn(VII) at acidic pH. The intermediate manganese products participate in Mn(VII) oxidation process most likely as both oxidants and catalysts with their generation/stability/reactivity affecting by the presence of NOM, ligand, cations, and anions in water matrices. This work presents the state-of-the-art findings on Mn(VII) oxidation of EOCs, especially highlights the significant roles of manganese products, which advances our understanding on Mn(VII) oxidation and its application in future water treatment processes.

An atom-economical protocol for synthesizing indazole N-oxides from readily available N-nitrosoanilines and sulfoxonium ylides through the rhodium(iii)-catalyzed C-H activation and cyclization reaction is described here. This protocol employs nitroso as a traceless directing group. The transformation features powerful reactivity, tolerates various functional groups, and proceeds with moderate to good yields under an ambient atmosphere, providing a straightforward approach to access structurally diverse and valuable indazole N-oxide derivatives. Importantly, this new annulation process represents a hitherto unobserved reactivity pattern for the N-nitroso group.

A new method for reduction of N-nitroso aza-aliphatic cyclic compounds employing zinc in pressurized CO2–H2O medium has been developed. H2O and NH4Cl were used as hydrogen donors, and reduction was performed under environmentally benign conditions. The presented approach allowed to obtain the respective N-amino products selectively and in excellent yields (up to 97%).

An amination reaction of in situ generated gem-difluoro-enolates has been explored with electrophilic nitrogen sources. While their exposure to azodicarboxylates smoothly produced fluorinated α-amino ketones, reaction with nitrosoarenes (nitroso aldol reaction) furnished α-ketoamides in very high yields (up to 94%). The reaction is very fast (typically completed within 5 min) and scalable and tolerates various sensitive functional groups. Synthetic utility of this process was highlighted through the production of diverse nitrogen heterocycles and an orexin receptor antagonist.

Reaction of commercial ruthenium complexes M31 and M20 with 2-nitrostyrene gave a new nitroso-chelated cyclic η1-acyl ruthenium(II) complexes Ru-4 and Ru-6 respectively instead of expected Hoveyda-Grubbs type (pre)catalyst Ru-3. New complexes were characterized by means of standard analytical techniques and their crystallographic structure has been confirmed by X-ray structural analysis. It was found that Ru-4 and Ru-6 do not exhibit any activity in standard metathesis reactions. However, a dramatic increase of activity was observed upon treatment with (trimethylsilyl)diazomethane, allowed for the successful application of Ru-4 in ROMP of endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid dimethyl ester. Moreover, such complexes can be effective catalysts of transfer hydrogenation of ketones as well as cycloisomerization reactions.

Oxygen atom transfer reactions are receiving increasing attention because they bring about paramount transformations in the current biomass processing industry. Significant efforts have therefore been made lately in the development of efficient and scalable methods to deoxygenate organic compounds. One recent alternative involves the modification of the Cadogan reaction in which a Mo(VI) core catalyzes the reduction of o-nitrostyrene derivatives to indoles in the presence of PPh3. We have used density functional theory calculations to perform a comprehensive mechanistic study on this transformation, in which we find two clearly defined stages: an associative path from the nitro to the nitroso compound, characterized by the reduction of the catalyst in the first step, and a peculiar mechanism involving oxazaphosphiridine and nitrene intermediates leading to an indole product, where the metal catalyst does not participate.

The first general protocol for the direct reductive N-functionalization of aliphatic nitro compounds is presented. The nitro group is partially reduced to a nitrenoid, with a mild and readily available combination of B2 pin2 and zinc organyls. Thereby, the formation of an unstable nitroso intermediate is avoided, which has so far severely limited reductive transformations of aliphatic nitro compounds. The reaction is concluded by an electrophilic amination of zinc organyls.

Based on first-principles density functional theory (DFT), the adsorption performance of MnO2(1 1 0) surface for NO and O2 was calculated, and the deposition of (MnO2)3cluster on the γ-Al2O3(1 1 0) surface was studied. In addition, the adsorption and co-adsorption of NO and O2 on the surface of (MnO2)3/Al2O3 were further calculated. The results showed that NO was more inclined to adsorb on the four-coordinated Mn(Ⅳ) sites on the MnO2(1 1 0) surface (the maximum Eads was −75.35KJ·mol−1). There were very few O2 adsorption sites on the MnO2(1 1 0) surface, and only the vacancies between adjacent Mn(IV) could adsorb O2 stably. PDOS analysis showed that the hybridization between Mn 3d orbital and N 2p (or O 2p) orbital was the main reason for Mn-N bonds (or Mn-O bonds). The (MnO2)3 cluster tended to load on Al2O3(1 1 0) surface in a flat six-membered ring structure. There are abundant active oxygen sites on the (MnO2)3/Al2O3 surface, which had an excellent ability to adsorb NO (the maximum Eads was −278.24 KJ·mol−1). NO molecules interacted with surface-active oxygen to generate nitroso, and NO2 was easily desorbed from the (MnO2)3/Al2O3 surface. The co-adsorption of NO and O2 on the (MnO2)3/Al2O3 surface formed an ONOO* structure, which could decompose to form adsorbed NO2* and O*. Compared with single-phase manganese oxide crystals, manganese oxide clustered on γ-Al2O3 had superior NO adsorption performance and may have excellent catalytic oxidation properties.

Highly-functionalized pyrroles could be effectively synthesized from 3,6-dihydro-1,2-oxazines using a heterogeneous copper on carbon (Cu/C) under neat heating conditions. Furthermore, the in situ formation of 3,6-dihydro-1,2-oxazines via the hetero Diels–Alder reaction between nitroso dienophiles and 1,3-dienes and the following Cu/C-catalyzed pyrrole synthesis also provided the corresponding pyrrole derivatives in a one-pot manner.

An iodine mediated regio-selective nitrosation of imidazo[1,5-a]N-heteroarenes is reported using TBN as nitroso source. This method afford synthetically useful and medicinally interesting 3-nitroso imidazo[1,5-a]N-heteroarenes in moderate to good yields with good functional group tolerance. Further, this reaction could applicable on gram-scale level synthesis.

A chiral N,N'-dioxide/Copper(II) complex-catalyzed highly regio- and enantioselective nitroso Diels-Alder (NDA) reaction of 2-nitrosopyridines with 1,3-diene-1-carbamates was described. A series of 3,6-dihydro-1,2-oxazines were obtained in good to excellent yields and ee values. On the basis of the control experiments, ESI-MS analysis and the absolute configuration of the product, a possible transition state model was proposed to explain the stereocontrol.

In this letter, an unprecedented cross-coupling reaction between copper carbene and nitroso radical has been developed. This radical-carbene coupling reaction (RCC reaction) offers a novel approach for the preparation of various isoxazolines, which features the construction of C-C, C-O, and C═N bonds in a one-pot process. The synthetic utility of our method is further enhanced by its mild reaction conditions, wide substrate scope, and simple procedures.

N-Nitroso CHF2-pyrazolines were synthesized from in situ generated difluoromethyldiazomethane (CF2HCHN2), tert-butyl isonitrite (tBuONO), and alkenes. The synthesis of representative CHF2-pyrazoles and CHF2-oxazolines was also performed.

The direct reaction between 2,7-bis(2-pyridinyl)-1,8-naphthyridine (bpnp) and Pd(CH3COO)2 in CF3COOH yields the new dinuclear palladium(II) complex [Pd2(bpnp)(μ-OH)(CF3CO2)2](CF3CO2) (1). Similarly, substitution of Pd(CH3CN)4(BF4)2 with bpnp in DMF gives [Pd2(bpnp)(μ-OH)(DMF)2](BF4)3 (2). Treatment of 1 or 2 with Cl– readily provide the chloro-substituted species [Pd(bpnp)(μ-OH)(Cl)2]+. All complexes were characterized by spectroscopic methods, and the structure of 2 was further confirmed by X-ray crystallography. Complex 1 is an efficient catalyst for the reduction of aromatic nitro compounds leading to the corresponding aniline derivatives under atmospheric pressure of hydrogen at 50 °C. The mechanistic pathway of the catalysis is investigated. From the reaction pathway, it is suggested that a facile condensation of nitroso and hydroxylamine intermediates is enabled by the dipalladium system and the desired transformation proceeds smoothly under mild reaction conditions to yield the reduced product.

o-Iodoxybenzoic acid (IBX) is confirmed as a powerful tool for the oxidation of hydroxylamines. The synthetic route is demonstrated as efficient and user friendly, and is exploited on various carbohydrate-derived N,N-disubstituted hydroxylamines (cyclic, acyclic, and functionalized ones), affording the corresponding nitrones in good yields and regioselectivity. N-Monosubstituted hydroxylamines revealed an interesting divergent behavior depending on the reaction conditions. While IBX oxidation in dimethyl sulfoxide at 45 °C furnished oximes as reported, the oxidation in dichloromethane at room temperature afforded efficiently the unusual corresponding nitroso dimers.

A series of derivatives of nitroso-substituted cubane were designed through the substitution of hydrogen atoms by nitroso groups one by one. The heats of formation (HOFs) were calculated to explore the thermal stability. The bond dissociation energies (BDEs) and the bond orders of the trigger bonds were also investigated to explore the molecular stability kinetically. Furthermore, the steric effect was confirmed as the determinant of molecular stability for title molecules. To explore the detonation properties, the detonation pressure (P), the detonation velocity (D), the heat of detonation (Q), and the specific density (ρ) were calculated by using the empirical Kamlet-Jacobs (K-J) equations. To predict the sensitivity, the characteristic drop height (H50) is calculated. Based on our calculations, the octanitrosocubane is found with detonation parameters (D = 9.03 km/s, P = 36.96 GPa) better than that of RDX with enough stability.

Certain oximes form nitric oxide upon reaction with 4-phenyl-1,2,4-triazole-3,5-dione (PTAD). The oximes appear to undergo an Alder-ene reaction with the PTAD enophile to form a nitroso intermediate capable of dimerization and/or nitric oxide formation. Upon exposure to oxygen, the nitroso compounds eventually form ketones. This reaction may serve as a model for the study of nitric oxide synthase (NOS), the enzyme responsible for physiological production of nitric oxide. NOS is known to produce an oxime intermediate which reacts with oxygen to produce nitric oxide and citrulline.

The article describes one-pot synthesis and structural elucidation of tc-[Ru-II(pap)(2)(L)]ClO4 [1]ClO4 and tc-[Ru-II(pap)(2)(L'(-))]ClO4 [2]ClO4, which were obtained from tc-[Ru-II(pap)(2)(EtOH)2](ClO4)(2) and benzofuroxan (L = 1,2-dinitrosobenzene, an intermediate tautomeric form of the biologically active benzofuroxan, L'(-) = 2-nitrosoanilido, pap = 2-phenylazopyridine, tc = trans and cis corresponding to pyridine and azo nitrogen donors of pap, respectively). The same reaction with the newly synthesized and structurally characterized metal precursor cc-Ru-II(2,6-dichloropap)(2)Cl-2, however, affords isomeric ct-[Ru-II(2,6-dichloropap)2(L-)](+) (3a+()) and tc-[RuII(2,6-dichloropap)(2)(L-)](+) (3b(+)) (cc, ct, and tc with respect to pyridine and azo nitrogens of 2,6-dichloropap) with the structural authentication of elusive ct-isomeric form of {Ru(pap)(2)} family. The impact of trans or cis orientation of the nitroso group of L/L' with respect to the N=N (azo) function of pap in the complexes was reflected in the relative lengthening or shortening of the latter distance, respectively. The redox-sensitive bond parameters of 1(+) and 3(+) reveal the intermediate radical form of L-, while 2(+) involves in situ generated L'(-). The multiple redox processes of the complexes in CH3CN are analyzed via experimental and density functional theory (DFT) and time-dependent DFT calculations. One-electron oxidation of the electron paramagnetic resonance-active radical species (1(+) and 3(+)) leads to [Ru-II(pap)(2)(L)](2+) involving fully oxidized L-0 in 1(2+) and 3(2+); the same in 2(+) results in a radical species [Ru-II(pap)(2)(L'(center dot))](2+) (2(2+)). Successive reductions in each case are either associated with pap or L/L'(-)-based orbitals, revealing a competitive scenario relating to their pi-accepting features. The isolated or electrochemically generated radical species either by oxidation or reduction exhibits near-IR transitions in each case, attributing diverse electronic structures of the complexes in accessible redox states.

A regioselective synthesis of nitrosoimidazoheterocycles from the reaction of 2-aminopyridines and acetophenones in the presence of NaNO2 and I2 is described. The reaction is suggested to proceed by a domino process involving sequential imine formation, iodination, iodide displacement by the nitro group, and finally intramolecular cyclization. Reaction of these 3-nitrosoimidazo[1,2-a]pyridines with aldehydes in the presence of Fe/AcOH furnished 5-substituted pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolines by reduction of the nitroso group followed by a Pictet–Spengler reaction in one pot. The synthesized compounds were assessed for their antibacterial and antifungal activities.

An efficient and mild protocol for regioselective synthesis of N-Nitroso aryl ketones by palladium-catalyzed direct acylation of arenes using N-Nitroso as directing groups is described. This reaction proceeded smoothly and could tolerate a variety of functional groups. Moreover, this chemistry offers a convenient access to a range of indazoles.

The effects of Mn precursors on structure defects and NO catalytic mechanism over Ce0·6Mn0.4Ox catalysts were fully investigated. The Ce0·6Mn0.4Ox-Ac catalyst, synthesized by using MnAc2 as a Mn precursor, showed the best catalytic activity for NO conversion (86.9%) at 250 °C under high space velocity (40,000 mL g−1 h−1). Detailed structure-activity relationship reveals that the abundant oxygen vacancies and the highly migratory oxygen species formed on Ce0·6Mn0.4Ox are the crucial factors that leading to the better NO oxidation activity than that of the other Ce0·6Mn0.4Ox-Y (Y NO3, SO4, Cl) catalysts. In situ DRIFTS technique confirms that the differences in formation mode and desorption ability of N-based (nitrates, nitrites, and dimer nitroso) intermediate species are the vital factors for NO high-efficiency catalytic oxidation. The highly reactive surface intermediate species, like monodentate nitrates, were observed particularly on Ce0·6Mn0.4Ox-Ac catalyst, so that the NO oxidation performance on Ce0·6Mn0.4Ox-Ac catalyst was more active comparing with other Ce0·6Mn0.4Ox-Y catalysts. This study can broaden the horizons for understanding NO catalytic oxidation mechanism on serial Ce0·6Mn0.4Ox catalysts and serve as a reference guide in design of structure defects for functional materials by modulating precursor species.

Oxygen-insensitive NAD(P)H:nitroreductases (NR) reduce nitroaromatics (Ar-NO2) into hydroxylamines (Ar-NHOH) through nitroso (Ar-NO) intermediates. Ar-NO may be reduced both enzymatically and directly by reduced nicotinamide adenine dinucleotide or its phosphate NAD(P)H, however, it is unclear which process is predominant in catalysis of NRs. We found that E. coli NR-A (NfsA) oxidizes 2 mol of NADPH per mol of 2,4,6-trinitrotoluene (TNT) and 4 mol of NADPH per mol of tetryl. Addition of ascorbate, which reduces Ar-NO into Ar-NHOH, changes the stoichiometry NADPH/Ar-NO2 into 1:1 (TNT) and 2:1 (tetryl), and decreases the rate of NADPH oxidation. Ascorbate does not interfere with the oxidation of NADPH during reduction of quinones by NfsA. Our analysis of ascorbate inhibition patterns and both enzymatic and non-enzymatic reduction of nitrosobenzene suggests that direct reduction of Ar-NO by NADPH rather than enzymatic reduction is the predominant mechanism during nitroaromatic reduction.

The development of transition metal-catalyzed oxidative C–H/C–H cross-coupling between two (hetero)arenes to forge aryl-heteroaryl motifs under mild conditions is an appealing yet challenging task. Herein, we disclose a rhodium-catalyzed oxidative C–H/C–H cross-coupling reaction of an N-nitrosoaniline with a heteroarene under mild conditions. The judicious choice of the N-nitroso group as a directing group enables heightened reactivity. The coupled products could be transformed expediently to (2-aminophenyl)heteroaryl skeletons.

The current investigation reports the preparation of a novel system, Cu/SiO2@NiFe2O4, as characterised by XRD, XPS, IR, SEM-EDS, TEM, ICP-AES and VSM data. Its catalytic activity was explored in nitroarene reduction using 4-nitrophenol as the model substrate for studying the reaction kinetics. The studies revealed the rate constant of the reaction at room temperature to be 0.325 min−1. Each test reaction here contained only 10.6 μg of copper, wherein the activity factor was 0.511 s−1 mg−1, which is by far the highest for any non-noble metal catalyst reported for this reaction. Moreover, the energy of activation of the reaction was found to be 30.4 kJ mol−1, which falls in the lower range of the average Eact reported in the literature for the reaction under study. Further insights on the reaction pathway indicated that the reaction followed a direct route for nitro-reduction via the formation of a nitroso derivative. Overall, we present herein an economical, efficient and environmentally benign methodology for nitroarene reduction using the designed catalyst.

Nitrosation of anilines at the ortho position was found to proceed on a ruthenium hydridotris(pyrazolyl)borato (Tp) complex. Reactions of [TpRuCl2(NO)] (1) with primary anilines 4-NH2C6H4R (R = tBu, H) in the presence of excess Et3N in CH2Cl2 gave amine-chelated nitrosoarene complexes [TpRuCl{N(═O)–C6H3R–NH2-κ2N,N}] (R = tBu (2a), H (2b)). Use of 2,4,6-trimethylaniline afforded an aryldiazenido complex [TpRuCl2{NNC6H2(Me)3}] (3) without forming the nitrosation product because of the introduction of the Me substituents at the ortho positions. On the other hand, in the case of secondary amines (N-methylanilines 4-NH(Me)C6H4R (R = tBu, H)), similar reactions gave amine-chelated nitroso complexes [TpRuCl{N(═O)–C6H3R–NHMe-κ2N,N}] (R = tBu (4a), H (4b)) and imine-chelated nitroso complexes [TpRuCl{N(═O)–C6H3R–N═CH2-κ2N,N}] (R = tBu (5a), H (5b)). Conversion of 4b into 5b by O2 was disclosed by 1H NMR monitoring. Moreover, oxidative reaction of 2a afforded an amide-chelated nitroso complex [TpRuCl{N(═O)–C6H3(tBu...

A highly efficient enantioselective nitroso Diels-Alder reaction of 6-methyl-2-nitroso pyridine with various 1,3-dienes was successfully developed using a Cu(i)/(S)-TF-BiphamPhos complex as the catalyst. For most of the cyclic dienes, synthetically important heterocyclic 3,6-dihydro-1,2-oxazines were obtained in high yields with excellent regio-, diastereo- and enantioselectivities. Acyclic 2-silyloxy-1,3-diene also worked well in the reaction.

C25H20AsN2O3Rh, triclinic, P-1 (no. 1), a = 9.2781(15) Å, b = 10.1405(15) Å, c = 13.303(2) Å, α = 99.789(5)°, β = 107.971(5)°, γ = 94.089(5)°, V = 1162.9(3) Å3, Z = 2, R gt (F) = 0.0578, wR ref (F 2 ) = 0.1833, T = 100(2) K.

Activated carbon fibers (ACFs) can effectively remove pollutants including nitrogen oxides, sulfur oxides and trace metals due to their rich micropores and large specific surface area. This work aims to investigate the roles of surface carbon–oxygen and nitrogen–oxygen species on the removal of hydrogen chloride (HCl) using viscose-based ACFs. To evaluate the effect of surface carbon–oxygen and nitrogen–oxygen groups, commercial viscose-based ACFs were treated by thermal treatment (900 °C) and chemical impregnation using H2O2, HNO3 and Cu(NO3)2. Pore volumes, average pore sizes and specific surface areas were separately characterized by t-plot method, density functional theory and Brunauer–Emmett–Teller theory. The surface morphology of the ACFs was observed by a scanning electron microscope. An X-ray photoelectron spectroscopy (XPS) technique was applied to determine the specific ratios of surface oxygen and nitrogen groups. Temperature programmed desorption was performed to investigate HCl adsorption behaviors over the ACFs. As experimental results, the thermal process decreased the carbon–oxygen groups while H2O2 impregnation increased the carbon–oxygen groups (especially carbonyl and carboxyl). Nitroso and nitro groups were introduced onto the carbon surface after HNO3 and Cu(NO3)2 treatments. The removal efficiency of HCl was improved slightly by H2O2 modification due to the increase of carbon–oxygen groups, and significantly by HNO3 and Cu(NO3)2 treatments because of newly formed nitrogen–oxygen groups. Nitroso and nitro groups show significant promotion of HCl retention ability over the ACFs surface. Moreover, HCl removal efficiency was much more influenced by nitroso than nitro groups.

It is postulated that cold atmospheric plasma (CAP) can trigger a therapeutic shielding response in tissue by creating a time- and space-localized, burst-like form of oxy-nitrosative stress on near-surface exposed cells through the flux of plasma-generated reactive oxygen and nitrogen species (RONS). RONS-exposed surface layers of cells communicate to the deeper levels of tissue via a form of the ‘bystander effect,’ similar to responses to other forms of cell stress. In this proposed model of CAP therapeutics, the plasma stimulates a cellular survival mechanism through which aerobic organisms shield themselves from infection and other challenges.

A palladium-catalyzed direct ortho-alkoxylation of N-alkyl-N-nitrosoarylamines was developed in which alcohols were used as the alkoxylation reagents and PhI(OAc)2 was employed as the oxidant. The protocol was available for both primary and secondary alcohols. The products were transformed to o-alkoxy-N-alkylanilines expediently by a simple reduction.

Denitrifying sulfide removal (DSR) process simultaneously removes nitrate, sulfide and organic matters in the same reactor. This study applied Azoarcus sp. NSC3 and Pseudomonas sp. CRS1 mix for DSR tests in autotrophic, heterotrophic and mixotrophic growths. Negligible NO-compounds were noted in heterotrophic or mixotrophic growths, while most cells were damaged and bound with NO-compounds in autotrophic growth. Nitroprusside (SNP) ions were applied as model compound to reveal the formation of nitrososulfide complex (RSNO) by nitroso (NO(+)) and excess sulfide (S(2-)), rather than the previously proposed mechanism by direct reaction between nitric oxide (NO) and S(2-). We speculated that RSNO was then abiotically decomposed to NO and elemental sulfur in the presence of biological cells. A revised nitrogen cycle considering interactions with sulfur compounds was proposed. We also speculated that SNO and NO were inhibitory to the functional strains, whose efficient removals were essential to reach high-rate DSR performance.

Iron(II) and palladium(II) phthalocyanines have been established as recyclable heterogeneous catalysts for the reduction of aromatic nitro compounds to corresponding amines using diphenylsilane/sodium borohydride as hydrogen sources in ethanol. Various reducible functional groups, such as acetyl, ester, cyano, amide, sulphonamide and carboxylic acid etc. were well tolerated, and the methods were applicable up to gram scale. Mechanistic studies showed that reduction of nitro group proceed through direct (nitroso) pathway and possibly iron or palladium phthalocyanines activates nitro group for reduction. FePc and PdPc also catalyzed the generation of hydrogen from the combination of diphenylsilane/sodium borohydride and ethanol. Iron and palladium (II) phthalocyanines has been established as an efficient recyclable catalytic systems for reduction of nitroarenes with green solvent system. Various nitro substituted aromatics and heteroaromatics has been successfully reduced to corresponding amines in good to excellent yields. The present methods have also been productively applicable for gram scale reactions.

A practical method for α-amination of α-alkyl-β-keto­esters using hydroxamic acids is described. In this protocol, an oxidative N-acylnitroso aldol reaction is catalyzed by magnesium chloride in the presence of the oxidant tert-butyl hydroperoxide.

In treatment of trans-[Ru(NO)(NH3)4(OH)]Cl2 with concentrated sulfuric acid on heating trans-[Ru(NO)(NH3)4(SO4)](HSO4)·H2O (I) is obtained with a yield close to quantitative. In the interaction of the saturated solution of I with a saturated NaNO3 solution a trans-[Ru(NO)(NH3)4(SO4)]NO3·H2O (II) precipitate forms whose structure is determined by single crystal XRD: space group P212121, a = 6.8406(3) A, b = 12.6581(5) A, c = 13.3291(5) A. A monodentately coordinated sulfate ion is in the trans-position to the nitroso group. Compound II is characterized by IR spectroscopy, powder XRD, and diffuse reflectance spectroscopy. The process of its thermolysis is studied; by differential scanning calorimetry the thermal effect of the dehydration reaction occurring on heating to 120°C (ΔH = 58.9 ± 1.5 kJ/mol) is estimated. The final product of the thermolysis of II is a mixture of Ru and RuO2.

ZIF-8 is built with Zn2+ tetrahedrally bridging with imidazole units, whereas ZIF-67 has the similar structure with Co2+ replacing the Zn ions. ZIF-8 and ZIF-67 were synthesized by a single step at room temperature, and the detailed characterization through XRD and FE-SEM study revealed similar surface morphology of the two isostructural ZIFs. Again, the chemical and thermal stability studies exhibited the better stability of ZIF-8 over ZIF-67. The through characterizations also revealed the better surface area and porosity and adsorption of 4-nitrophenol over ZIF-8 compare to ZIF-67. Interesting, in spite of inferior physical properties, ZIF-67 revealed better electrocatalytic properties between the isostructural ZIFs. ZIF-67 showed unprecedentedly fast reduction of 4-nitrophenol to 4-aminophenol, whereas the reduction of 4-nitrophenol over ZIF-8 took almost 180 min, in-spite of better adsorption. The detailed mechanistic studies revealed that the electrocatalytic reduction of 4-nitrophenol over ZIF-8 electrode underwent through an orthodox 6e− system pathway to produce 4-aminophenol through hydroxyl amine and nitroso containing intermediates. Whereas, ZIF-67 produced hydrogen through water splitting that directly reduced 4-nitrophenol to 4-aminophenol with complete product selectivity.

The effect of polyethylene glycols (PEGs) with molecular weights of 2000, 6000, 13000, and 20000 on the sensitivity of the thermal lens determination of cobalt(III) using nitroso-R-salt and 2-nitroso-1-naphthol is studied. At the polymer concentration as low as 10%, the sensitivity coefficient significantly increases and the detection limit decreases by a factor of 1.5–2 with respect to the determination in an aqueous medium without PEG. This effect is accompanied by an increase in sensitivity due to an increase in the absorbance of the cobalt complexes in PEG solutions at the operating wavelength. Under optimal conditions, the detection limits for cobalt(III) are 6 and 10 ng/mL with nitroso-R-salt and 2-nitroso-1-naphthol, respectively.

Isomers of 1-nitroso-3-nitro-1,2,4-triazol-5-one-2-oxide are of interest in the contest of high explosives and were found to have true local energy minima at the hybrid DFT-B3LYP/aug-cc-pVDZ level. The optimised structures, vibrational frequencies and thermodynamic values for triazol-5-one-N-oxides have been obtained in the ground state. Kamlet–Jacob equations were used to evaluate the performance of model compounds based on the predicted density and the calculated heat of explosion. The detonation properties (D = 10.15–10.46 km/s, P = 50.86–54.25 GPa) of designed compounds were found to be promising compared with 1,3,5-trinitro-1,3,5-triazine (D = 8.75 km/s, P = 34.7 GPa), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (D = 8.96 km/s, P = 35.96 GPa), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (D = 9.20 km/s, P = 42.0 GPa) and octanitrocubane (D = 9.90 km/s, P = 48.45 GPa). The replacement of secondary hydrogen by nitroso group appears to be a particularly promising area for investigatio...

A rapid method for the synthesis of long-chain fluorinated compounds using a C–C bond-cleavage reaction was developed. Selectfluor was the most effective fluorinating agent of those tested in this study. Long-chain fluoro dioxo nitriles were formed from isoxazoline N-oxides via nitroso intermediates.