Aromatic Nitro Derivatives Research Articles

Плазмохимический синтез нитропроизводных аценафтена в поле токов высокой частоты при пониженном давлении

Plasma-chemical processing devices are widely used in practice and are an integral part in microelectronics, medicine, light industry and nanotechnology. In addition, they are used as methods for modifying the modern materials surfaces and in liquids processing. The paper considers preparation of the aromatic compound nitro derivatives under the action of capacitive high-frequency electrodeless discharge at the gas--liquid interface with the reduced pressure. During the plasma-chemical treatment of the reaction mixture containing the 1,2-dihydroacenaphthylene (acenaphthene), its complete conversion was observed, which was confirmed by detection of the acenaphthene mono- and dinitro-derivatives, as well as of the side chain oxidation products, in the reaction products. The proposed method of implementing nitration reaction of the aromatic substances, which belongs to the new instrumental methods of organic synthesis along with photochemistry and electrochemical synthesis, allows direct binding of the molecular nitrogen and oxygen into the valuable nitrogen-containing organic compounds. Study results demonstrate effective introduction of the plasma chemistry methods in chemical technology not only for the purposes of oxidative destruction of the organic substances, but also as the physicochemical tools for the fine organic synthesis allowing selective functionalization of the polynuclear aromatic compounds

Detection of nitroaromatics by a Zn(II)-containing coordination polymer derived from a 1,2,3-triazole-based tricarboxylate ligand

The Dimroth azide–enolate cycloaddition between dimethyl 5-azidoisophthalate and ethyl acetoacetate was used to generate 5-(4-carboxy-5-methyl-1H-1,2,3-triazol-1-yl)isophthalic acid (H3L) as a novel tricarboxylate ligand with a 1,2,3-triazole ring in the central unit with a view to employ it in the preparation of coordination polymers. The reaction of this ligand with Zn(NO3)2·6H2O in a mixture of N,N-dimethylformamide (DMF) and water at 95 °C for 72 h afforded [Zn4L2(OH)2(H2O)DMF2]n, which has been characterized by single crystal X-ray crystallography, infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. The fluorescence of this coordination polymer was investigated, and its ability to detect various nitroaromatics by fluorescence quenching was examined. 4-Nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol and 4-nitrotoluene have been identified as the aromatic nitroderivatives for which the coordination polymer exhibits a fluorescence quenching in the range of 91% to 82%.

Secondary Formation of Aromatic Nitroderivatives of Environmental Concern: Photonitration Processes Triggered by the Photolysis of Nitrate and Nitrite Ions in Aqueous Solution.

Aromatic nitroderivatives are compounds of considerable environmental concern, because some of them are phytotoxic (especially the nitrophenols, and particularly 2,4-dinitrophenol), others are mutagenic and potentially carcinogenic (e.g., the nitroderivatives of polycyclic aromatic hydrocarbons, such as 1-nitropyrene), and all of them absorb sunlight as components of the brown carbon. The latter has the potential to affect the climatic feedback of atmospheric aerosols. Most nitroderivatives are secondarily formed in the environment and, among their possible formation processes, photonitration upon irradiation of nitrate or nitrite is an important pathway that has periodically gained considerable attention. However, photonitration triggered by nitrate and nitrite is a very complex process, because the two ionic species under irradiation produce a wide range of nitrating agents (such as •NO2, HNO2, HOONO, and H2OONO+), which are affected by pH and the presence of organic compounds and, in turn, deeply affect the nitration of aromatic precursors. Moreover, aromatic substrates can highly differ in their reactivity towards the various photogenerated species, thereby providing different behaviours towards photonitration. Despite the high complexity, it is possible to rationalise the different photonitration pathways in a coherent framework. In this context, this review paper has the goal of providing the reader with a guide on what to expect from the photonitration process under different conditions, how to study it, and how to determine which pathway(s) are prevailing in the formation of the observed nitroderivatives.

Photocrosslinked hybrid composites with Ag, Au or Au-Ag NPs as visible-light triggered photocatalysts for degradation/reduction of aromatic nitroderivatives

Flexible free-standing nanocomposite films embedding Ag, Au or Au-Ag nanoparticles were successfully synthesized by a simple one-pot process, namely photocrosslinking of organic matrix in tandem with photogeneration of noble metal nanoparticles, both initiated by Irgacure 819 photoinitiator. The achieved materials were characterized by UV-vis spectroscopy and transmission electron microscopy, in order to evaluate the morphology, size and shape of the prepared metallic catalysts. The photocatalytic activity of the obtained catalysts was evaluated following the photodegradation of 4-nitroaniline under ambient conditions and visible irradiation or the photoreduction of 4-nitroaniline to p-phenylendiamine in the presence of NaBH4. Further modification of the organic matrix by the inclusion of 3-acrylamidophenylboronic acid monomer, allowed us to prepare a catalyst with the hydrogen donor compound embedded in the polymer film. The photoreduction of 4-nitroaniline to p-phenylenediamine occurred in the presence of the new photocatalyst without the addition of a reducing agent in the reaction mixture, although the reaction is slower than that accomplished in the presence of NaBH4.

Mechanochemical Catalytic Transfer Hydrogenation of Aromatic Nitro Derivatives.

Mechanochemical ball milling catalytic transfer hydrogenation (CTH) of aromatic nitro compounds using readily available and cheap ammonium formate as the hydrogen source is demonstrated as a simple, facile and clean approach for the synthesis of substituted anilines and selected pharmaceutically relevant compounds. The scope of mechanochemical CTH is broad, as the reduction conditions tolerate various functionalities, for example nitro, amino, hydroxy, carbonyl, amide, urea, amino acid and heterocyclic. The presented methodology was also successfully integrated with other types of chemical reactions previously carried out mechanochemically, such as amide bond formation by coupling amines with acyl chlorides or anhydrides and click-type coupling reactions between amines and iso(thio)cyanates. In this way, we showed that active pharmaceutical ingredients Procainamide and Paracetamol could be synthesized from the respective nitro-precursors on milligram and gram scale in excellent isolated yields.

Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane.

The metal-free reduction of nitro compounds to amines mediated by trichlorosilane was successfully performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two synthetically relevant intermediates (precursors of baclofen and boscalid).

Relationship of polycyclic aromatic hydrocarbons with oxy(quinone) and nitro derivatives during air mass transport

Airborne concentrations of Polycyclic Aromatic Hydrocarbons (PAH), quinone and nitro derivatives have been measured at three sites on the coast of Saudi Arabia to the north of the city of Jeddah. The PAH show a general reduction in concentrations from northwest to southeast, consistent with a source from a petrochemical works to the northwest of the sampling sites. In comparison, the concentrations of quinones show little variation between the sampling sites consistent with these being predominantly longer lived secondary pollutants formed from PAH oxidation. The nitro-PAH show a gradient in concentrations similar to but smaller than that for the PAH suggesting a balance between atmospheric formation and removal by photolysis. The 2-nitrofluoranthene:1-nitropyrene ratio increases from north to south, consistent with atmospheric chemical formation of the former compound, while the ratio of 2-nitrofluoranthene:2-nitropyrene is consistent with hydroxyl radical as the dominant reactant. An investigation of the changes in PAH congener ratios during air mass transport along the Red Sea coast shows consistency with reaction with a relatively low concentration of hydroxyl radical only for the day with the highest concentrations. It is concluded that while PAH degradation is occurring by chemical reaction, emissions from other locations along the air mass trajectory are most probably also leading to changes in congener ratios.

Electroanalysis of Nitro and Amino Derivatives of Polycyclic Aromatic Hydrocarbons

Electrochemical methods used for the investigation, determination and monitoring of carcinogenic nitro (NPAHs) and amino (APAHs) derivatives of polycyclic aromatic hydrocarbons are reviewed. Special emphasis is placed on the mechanisms of electrode reactions of NPAHs at traditional mercury electrodes and electrodes based on silver amalgam, and of APAHs at electrodes based on the different types of carbon materials, e.g., glassy carbon electrode, carbon paste electrode based on glassy carbon microbeads, or boron-doped diamond film electrode. Recently developed voltammetric and amperometric methods making use of electrochemical reduction or oxidation of NPAHs or APAHs for their sensitive and selective determination are discussed as well together with a brief survey of occurence and biological properties of these substance. Keywords: Review, Derivatives of polycyclic aromatic hydrocarbons, Nitro and amino derivatives, Reduction and oxidation mechanisms, Voltammetry, Amperometry, Electroanalysis, arcinogenic/mutagenic compounds, Voltammetric Determination, Amperometric Determination, HPLC-ED, glassy carbon electrode, (NPAHs), (APAHs) derivatives, gas chromatography (GC)

ChemInform Abstract: Role of Alkali Halides in the Synthesis of Nitrogen Containing Heterocycles by Reductive Carbonylation of Aromatic Nitro Derivatives Catalyzed by Ru3(CO)12.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: The Role of Co-Catalysts in the Reductive Carbonylation of Aromatic Nitro Derivatives Catalyzed by Transition Metal Carbonyl Clusters

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

1-(2-Pyridyl)-2-propen-1-ol: a multipurpose reagent in organic synthesis

A peculiar thermal behaviour of hydroxyallylpyridyl derivatives, likely associated to the weak acidity of the ‘picoline-type’ hydrogen atom and responsible for the formation of allyl inversion products, has been reported. The ‘mobility’ of the same hydrogen atom allowed the unprotected title compound to behave regioselectively as C-1, C-2 or C-3 carbon nucleophile depending on the thermal or base-promoted experimental conditions and on the kind of electrophile; moreover, the corresponding Hantzsch-type pyridine tautomer displayed a biomimetic ability to transfer hydrogen to aromatic and heteroaromatic nitro derivatives.

Transformations of Benzene Photoinduced by Nitrate Salts and Iron Oxide

This paper reports the results of a study on the transformation of benzene in the presence of solid nitrate salts (NaNO3, NH4NO3) under irradiation in a gas-solid photoreactor. Sodium and ammonium nitrate have been chosen as representative of the composition of atmospheric particulate, benzene as a model aromatic molecule. The purpose is to simulate the transformations that aromatic compounds undergo on the surface of dispersed particles in the atmosphere. Irradiation of sodium nitrate causes hydroxylation and nitration of benzene, yielding phenol and nitrobenzene. This is most likely due to the generation of •OH and •NO2 radicals upon nitrate photolysis, with •OH + O2 leading to the formation of phenol and •OH + •NO2 yielding nitrobenzene. The percentage of oxygen in the reaction environment influences the transformation pathways, with phenol formation being favoured and nitrobenzene formation depressed by high O2 concentration. In the presence of hematite (α-Fe2O3, another component of atmospheric particulate) very relevant formation of nitrobenzene takes place even with 21% oxygen (simulated air), indicating that the interaction between hematite and nitrate can lead to the formation of aromatic nitroderivatives on the surface of atmospheric particulate. The effect of hematite is possibly due to protonation of peroxynitrite, formed upon nitrate photoisomerisation, to peroxynitrous acid, a powerful nitrating agent. A similar effect leads to relevant formation of nitrobenzene under atmospheric conditions upon irradiation of the acid salt ammonium nitrate.

Thermodynamics of Formation of Molecular Complexes of Aromatic Nitro Derivatives with Lincomycin and β-Glycyrrhizic Acid

It was found that lincomycin and β-glycyrrhizic acid form 1:2 molecular complexes with aromatic nitro derivatives. Quantum-chemical calculations of lincomycin and β-glycyrrhizic acid were performed. These compounds form a cavity and, like podands, are capable of accommodating guest molecules. The formation constants and the thermodynamic characteristics of the complexes were calculated. A linear correlation was found between the formation constants of the molecular complexes of β-glycyrrhizic acid and the Hammett constants of the substituents in the nitro derivatives. The complexes of lincomycin and β-glycyrrhizic acid with aromatic nitro derivatives are formed by a common mechanism involving related bonds.

Indirect reduction of carbonyl and dinitro derivatives by an electrogenerated titanium (III) complex in non aqueous medium

Abstract Aromatic nitroderivatives or ketones react with low valent titanium reagents to give, respectively, the amines or alcohols and coupling products. We have studied, in a non aqueous medium (DMF), the selectivity of a titanium (III) species electrochemically generated from Cp 2 TiCl 2 for the reduction of the 4,4′-dinitrodibenzyle and the 9-fluorenone. The cyclic voltammograms of Cp 2 TiCl 2 were registered in the presence of the dinitroderivative or of the ketone. The ESR spectra of the Ti(III) species and of the anion-radicals were monitored under in situ electrolyses. For low values of the ratio [Cp 2 TiCl 2 ]/[substrate], the macroscale electrolyses performed at the potential of the first step of Cp 2 TiCl 2 yielded selectively the 4-amino-4′-nitrodibenzyle and the pinacol of the fluorenone. For higher ratios or at a more negative fixed potential, the diamine and the fluorenol become the main reaction products.

Photochemical reactivity of aromatic and heteroaromatic nitroderivatives in the presence of arylalkenes

The irradiation of styrene in the presence of nitroarenes in acetonitrile gives the corresponding nitrones in high yields. However, when 4-methyl-5-ethenylthiazole is used as arylalkene the starting material is converted to a pyrrole analogous of thianthrene. On the contrary, when 1,1-diphenylethylene is used, the main product observed is benzophenone. Nitrones are obtained only as minor products. An unusual coupling product, where a substitution reaction has occurred on the carbon bearing the nitro group, is also obtained. trans-Stilbene is unreactive under the same photochemical conditions, and it gives in low yields only benzaldehyde. Finally, indene gives, when aromatic nitro derivatives are used, only oxidation products, while, when heteroaromatic nitro derivatives are used, only substitution products on the nitro group are observed. The above described reactivity can be explained by using the results of AM1 semiempirical calculations on the frontier orbitals of the reagents. Both the nature of the LSOMO of the nitroarenes and the dipole moments of the reagents can account for the observed reactivity. The nitrone obtained in the photochemical reaction between styrene and nitrobenzene is used as starting material in a 1,3-dipolar cycloaddition reaction with styrene.

Carbonylative reduction of aromatic nitroderivatives to arylamines catalyzed by sulfur compounds

Aromatic nitroderivatives e.g. nitrobenzene can be carbonylatively reduced with CO in water-methanol media, at 120–150°C and 10–15 MPa pressure. Aniline is obtained with selectivity over 97% at 100% nitrobenzene conversion. Reaction proceeds in the presence of multicomponent catalyst consisting of the base (favourable are the strong bases: sodium hydroxide or methoxide) and sulfur compound. The ratio of catalytic effectiveness of sulfur compounds is as follows S:CS 2:H 2S:COS = 1:1.3:10:10. Vanadium (V) compound can be added to improve selectivity of aniline formation. Aromatic dinitroderivatives undergo this reaction and selectivity to one of two main products (phenylenediamine or nitroaniline) can be switched by the choice of reaction conditions.

Role of alkali halides in the synthesis of nitrogen containing heterocycles by reductive carbonylation of aromatic nitro-derivatives catalysed by Ru3(CO)12

The presence of alkali halides as co-catalysts in the reductive carbonylation of o-nitrobiphenyl 1 catalysed by Ru3(CO)12 strongly increases the rate of reactions and selectivity towards heterocyclization products [carbazole 2 and 5H-phenanthridin-6-one 3]. With sodium halides, depending on the anion, the selectivity for carbazole is in the order Cl– > Br–≈ F– I–; whereas the selectivity for 5H-phenanthridin-6-one is the reverse I– > Br–≈ F– > Cl–. The influence of the cation can be explained with the polarization of a CO ligand of the ruthenium cluster, due to the interaction of the alkali cation with the oxygen lone pair. In fact high yields (>80%) of heterocyclization products are obtained when the alkali cation is free to coordinate the CO. When this interaction is reduced, by sequestering the cation with crown-ethers, or better with cryptands, the yield of heterocyclic products is 14% and 0% respectively. The role of the anion and cation in the catalytic mechanism are discussed. The attempted extension of this reaction to other nitro-derivatives for the potential synthesis of aromatic heterocycles with larger rings are also reported.

ChemInform Abstract: Interactions Between 2‐Hydroxypyridine and Some Aromatic Nitro Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Polar effects in the ruthenium(0)-catalysed reductive carbonylation of aromatic nitro derivatives to give ureas and amines

Several nitrobenzene derivatives were submitted to reaction with carbon monoxide in cis-cyclooctene in the presence of catalytic amounts of Ru 3(CO) 12. The corresponding ureas and amines were formed in this reaction, while secondary amines derived from insertion of the nitrene intermediate at the allylic position of cis-cyclooctene were secondary products. The influence of the electronic parameters of the substituents on the conversion and the urea vs. amine ratio is discussed. Hydrogen atoms seem to derive from the solvent.

Sensitivity of electrokinetic detection of acidic aromatic nitro derivatives using column as a detector

A stainless-steel analytical column of 2 mm I.D. served as an electrokinetic detector. The minimum detectable amounts of nitrophenols eluted from both unmodified and chemically modified silica gel with n-heptane-acetone (90:10) acidified with 10 ppm of nitric acid were of the order of 10 −9−10 −11 mol. The minimum detectable quantity of dipicrylamine, 1.8·10 −13 mol, represents a detection sensitivity one order of magnitude higher than the highest possible using photometric detection.