Presence Of Nitro Group Research Articles

Inhibitory and Bactericidal Properties of a Number of Dihydroxyazo Compounds

Inhibitory and bactericidal properties of a number of dihydroxyazo compounds have been studied in the Postgate medium containing sulfate-reducing bacteria (SRB) in planktonic form. Sulfate-reducing bacterium strain Luk used in this study was phylogenetically closed (99% similarity of 16S rRNA genes) to the type strain Desulfomicrobium apsheronum 1105T isolated from petroleum reservoir. The number of sulfate-reducing bacteria was counted by a method called the direct microscopic count. Special counting chamber was used. Biogenic H2S concentration was defined daily by the iodometric titration. Small concentrations (5-20 mg/L) of the compounds under study have been used. These compounds induce a decrease of the bacterial cells quantity and H2S production by SRB. Dihydroxyazo compounds inhibit carbon steel corrosion and hydrogen permeation through the steel membrane in the presence of SRB. Corrosion tests of the carbon steel samples were carried out by weight-loss method. Most high corrosion rate of steel in the inoculated media is observed in third day of bacteria development when maximum concentration of H2S is reached (190 mg/L). Its value is equal to 0.28 g/(m2h). Protective effect of the bactericides depends on the structure of their molecules. For estimation of hydrogen permeation into metal, two-chamber cell with a vertical steel membrane similar to the Devanathan cell was used. Entrance side of the membrane contacted with the working solution. The measurements were conducted under corrosion potential, cathodic and anodic polarization of the entrance membrane side. The SEM image of the membrane entrance side after the hydrogen permeation test for 2 h in the inoculated media in the absence and presence of the inhibitors is compared. Effect of dihydroxyazo compounds depends on their molecular structure. A presence of nitro-group or Cl-atom and 1-phenyl-3-methylpirazole group in the molecule increases the bactericidal and inhibitory ability of the substance. At that, a number of SRB cells, production of hydrogen sulfide by them sharply decreases, inhibitory effect essentially increases and hydrogen permeation into metal is retarded by 2.5 times in the stationary phase of bacterial vital cycle.

Electrochemical and optical properties of a conducting polymer and its use in a novel biosensor for the detection of cholesterol

A simple and robust cholesterol biosensor was designed by immobilizing cholesterol oxidase (ChOx) onto a conducting polymer modified graphite electrode. For this purpose, monomer, (Z)-4-(4-(9H-carbazol-9-yl) benzylidene)-2-(4-nitrophenyl) oxazol-5(4H)-one (CBNP), was synthesized and electrochemically polymerized on an electrode to achieve an effective immobilization platform for enzyme immobilization. After electropolymerization of the monomer (CBNP), electrochemical and spectroelectrochemical properties were investigated. Through the presence of nitro group on the polymer backbone hydrogen-bonding between enzyme molecules and polymer was achieved. Moreover, strong π–π stacking between aromatic moities in the polymer and aromatic residues of the enzyme enables a sensitive and reliable biosensor by conserving the crucial structure of biological molecules during the enzymatic reaction. The efficient interaction of the enzyme with the polymer coated surface brings easy and long-life detection of the substrate, cholesterol. After successful immobilization of ChOx with the help of glutaraldehyde as the crosslinking agent, amperometric biosensor responses were recorded at −0.7V vs Ag wire in phosphate buffer (pH 7.0). KMapp (37.3μM), Imax (3.92μA), LOD (0.4063μM) and sensitivity (1.49μAμM−1cm−2) values were determined. Finally, the prepared biosensor was successfully applied for determination of cholesterol content in real blood samples.

Syntheses, studies and crystal structure of new coordination polymers of mercury (II) with phenylcyanamide derivative ligands

A series of compounds mercury (II), [Hg(CH2COCH3)L]n where L=anion of 4-NO2pcyd (4-nitro phenylcyanamide) (1), 4-Clpcyd (4-chloro phenylcyanamide) (2), 4-Brpcyd (4-bromo phenylcyanamide) (3) were synthesized from acetone and characterized by elemental analysis, IR, 1H NMR, 13C NMR and electronic absorption spectroscopies. Single crystal X ray analysis of 1 reveals coordination of phenylcyanamide ligand to Hg (II) unexpectedly occurred through amine nitrogen alone which is rare. Also the anion of acetone was coordinated to mercury by the carbon atom as well as oxygen atom from (CO) of another acetone anion. A theoretical study at DFT (B3LYP) level showed that the experimentally determined structure of the complex 1 is about 6.49 and 8.31kcal/mol, respectively in the gas phase and solvent more stable than its other bonding modes. In addition, this phenomenon was supported by NBO interaction energies and the much orbital contribution in the HOMO of ligand to interact with Hg (II) that all of these observations were raised from the presence of nitro group as electron withdrawing group. By using TD-DFT method, electronic absorption spectra of the compound 1 have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. Biological studies show the antibacterial activity of the complex 1 against Gram-positive and Gram-negative bacterial strains.

Synthesis and characterization of polyaniline and poly(aniline-co-o-nitroaniline) using vibrational spectroscopy

Due to the advantages of material abundance and synthetic simplicity, polyaniline can be used as a high capacity cathode material. However, its practical application in battery has been hindered by poor electrochemical utilization and cycling instability. To solve these problems, we synthesized the Polyaniline-co-o-nitroaniline aniline. The copolymers were synthesized for 1:1 and 1:4M ratios of aniline and o-nitroaniline in acidic medium using ammonium persulfate as oxidant and their properties were compared with that of polyaniline. The prepared samples have been characterized using number of techniques including Raman spectroscopy, FTIR, UV–vis, and conductivity. The polymers showed less electrical conductivity than polyaniline. Unlike polyaniline, the presence of nitro group caused higher frequency dependence of electrical conductivity. The FTIR bands at 1560, 1306 and 1148cm−1 are corresponding to the polyaniline salt. The Raman band observed in the range of 1100–1140cm−1 is the characteristic of conductive polyaniline and is due to the charge delocalization on the polymer backbone.

Synthesis, Electrical Conductivity, Spectral and Thermal Stability Studies on Poly(aniline-co-o-nitroaniline)

o-Nitroaniline units were incorporated in the polyaniline backbone through copolymerization with aniline. The copolymers were synthesized for 1:3 and 1:1 molar ratios of aniline and o-nitroaniline in acidic medium using potassium persulphate as oxidant and their properties were compared with that of polyaniline. The polymers showed less electrical conductivity than polyaniline. Unlike polyaniline, the presence of nitro group caused higher frequency dependence of electrical conductivity. Electronic spectra showed a blue shift in both the band of the copolymers due to the decrease in the extent of conjugation leading to lower conductivity, which could also be explained in terms of a decrease of delocalization of electron as evinced from electron para magnetic resonance (EPR) data. Thermo gravimetric analysis (TGA) revealed that copolymer derived from 1:1 molar ratio showed comparable thermal stability with polyaniline and the one derived from 1:3 molar ratios is thermally less stable than polyaniline. Activation energies for thermal degradation were estimated using Broido equation. The temperature dependence of electrical conductivity suggested charge transport is mainly through variable range hopping.

Novel Synthesis and Crystal Structures of Two α, α′-bis-Substituted Benzylidene Cyclohexanones: 2,6-Bis-2-nitro(benzylidene)cyclohexanone and 2,6-Bis-4-methyl(benzylidene)cyclohexanone

Two α,α′-bis-substituted benzylidene cycloalkanones have been synthesized in presence of SnCl4 and their crystal structures have been determined by means of X-ray diffraction. The bis(para-methyl) derivative, 2,6-bis-4-methyl(benzylidene)cyclohexanone 1 crystallizes in the orthorhombic space group Pbca with a = 9.413(2) A, b = 10.787(2) A, and c = 33.702(5) A, while bis(ortho-nitro) derivative, 2,6-bis-2-nitro(benzylidene)cyclohexanone in monoclinic P21/n space group with a = 8.482(2) A, b = 13.435(2) A, c = 15.377(3) A, and β = 92.96(2)°. In both compounds the olefinic bonds are in E-configuration, and the cyclohexyl rings adopt a sofa conformation. The phenyl rings are not coplanar with the planes of C=C–C(=O)–C=C fragments; the dihedral angles between these planes are 14.25(11) and 19.37(11)° in 1 and 60.50(6) and 63.26(6)° in 2. This twist might be regarded as the effect of the repulsive interactions between the hydrogen atoms from phenyl and cyclohexyl rings, and much larger values in 2 are certainly connected with the presence of nitro group in ortho-positions of the phenyl ring. It seems that, because of the lack of specific interactions the close packing requirements and the van der Waals forces are main factors determining the crystal packing. The phenyl rings are not coplanar with the planes of C=C–C(=O)–C=C fragments as the effect of the repulsive interactions between the hydrogen atoms from phenyl and cyclohexyl rings .

Original TDAE reactivity in benzoxa- and benzothiazolone series

We present herein an extension of the TDAE strategy using original heterocyclic carbaldehyde as electrophiles. We also evaluate the influence of the presence of nitro group on the reactivity. The TDAE-initiated reactions of various halomethyl and gem-dihalomethyl derivatives with non-nitrated carbaldehyde 1 or 2 formed the expected products accompagnied by original rearranged products while the presence of a nitro group just like the carbaldehyde 21 furnished only the expected products in good yields.

ChemInform Abstract: Development of Molecular Sieves‐Supported Palladium Catalyst and Chemoselective Hydrogenation of Unsaturated Bonds in the Presence of Nitro Groups.

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.

Antihyperglycemic activity of naphthylchalcones

The purpose of the present work was to investigate, following previous works, naphthylchalcones as antihyperglycemic agent in glucose loaded animal model, insulin secretion as well as the action of these compounds on glucose uptake in a target tissue of insulin. The naphthylchalcones were found to have an acute serum glucose-lowering effect in hyperglycemic normal rats. In addition, chalcones 2 and 4 stimulated significantly the insulin secretion induced by glucose. These results suggest that the presence of nitro group and their position in the phenyl rings are responsible for the antihyperglycemic activity of chalcones. Additionally, the effect of chalcones on serum glucose-lowering seems to be a consequence of insulin secretion and these chalcones represent potential compounds with strong antihyperglycemic properties.

Development of Molecular Sieves‐Supported Palladium Catalyst and Chemoselective Hydrogenation of Unsaturated Bonds in the Presence of Nitro Groups

AbstractThe chemoselective hydrogenation of unsaturated bonds and azide functionalities is achieved in the presence of nitro groups by a heterogeneous palladium catalyst supported on molecular sieves (MS3A). The present method shows a wide‐range of applicability with regard to substrates and the catalyst can be easily prepared and reused at least three times without any loss of activity.

Highly Chemo- and Regioselective Reduction of Aromatic Nitro Compounds Using the System Silane/Oxo-Rhenium Complexes

The reduction of aromatic nitro compounds to the corresponding amines with silanes catalyzed by high valent oxo-rhenium complexes is reported. The catalytic systems PhMe(2)SiH/ReIO(2)(PPh(3))(2) (5 mol %) and PhMe(2)SiH/ReOCl(3)(PPh(3))(2) (5 mol %) reduced efficiently a series of aromatic nitro compounds in the presence of a wide range of functional groups such as ester, halo, amide, sulfone, lactone, and benzyl. This methodology also allowed the regioselective reduction of dinitrobenzenes to the corresponding nitroanilines and the reduction of an aromatic nitro group in presence of an aliphatic nitro group.

New Gastroprotective Ferruginol Derivatives with Selective Cytotoxicity against Gastric Cancer Cells

The diterpene ferruginol has shown a strong protective effect in animal gastric ulcer models. In the present work, we report the gastroprotective effect and cytotoxicity of 16 new semisynthetic ester derivatives of ferruginol. The gastroprotective effect of these compounds was assessed with the HCl/EtOH-induced gastric lesions model in mice and the cytotoxicity was measured using MRC-5 fibroblasts, gastric adenocarcinoma (AGS) and liver hepatoma Hep G2 cells. The compounds were tested for a gastroprotective effect at a single oral dose of 20 mg/kg. The best gastroprotective effect was elicited by ferruginyl nicotinate ( 13), reducing the lesion index by 71 %, while the derivatives ferruginyl chloroacetate ( 2), ferruginyl palmitate ( 6), ferruginyl oleate ( 7), ferruginyl 3,5-dinitrobenzoate ( 11), ferruginyl 3-methylbenzofuran-2-carbonyl ester ( 12), ferruginyl indoleacetate ( 14), ferruginyl indolebutyrate ( 15) and ferruginyl pthalate ( 16) reduced the lesions by 49 - 66 %. The most promising compounds were 11, 13 and 14, presenting a gastroprotective effect higher or similar to that of ferruginol but with a high selectivity towards the tumor AGS cells. Among the three products, the most selective towards AGS cells was 14, followed by 13, and 11 (IC (50) values of 12, 22 and 29 microM, respectively). The isobutyrate 4, inactive as a gastroprotective agent, showed selective cytotoxicity against AGS and Hep G2 cells (IC (50) values of 60 and 39.2 microM, respectively). The cytotoxicity of the above cited compounds towards fibroblasts was >1000 microM. Considering the aliphatic esters of ferruginol, the best gastroprotective activity was found in the C (16) and C (18) derivatives but tended to decrease with increasing aliphatic chain unsaturation. For short-chain esters, the gastroprotective effect could be observed when the chain contained a chlorine atom. For aromatic esters, the presence of nitro groups or a nitrogen atom in the aromatic ring enhanced the gastroprotective activity. The compounds with the best gastroprotective effect and the highest selectivity against tumor cells bear an amino group (indoleacetate and nicotinate) or nitro group (3,5-dinitrobenzoate).

In Vitro antifungal activity of 2-(4-substituted phenyl)-3(2H)-isothiazolones

The in vitro antifungal activity of several N2-phenyl-3(2H)-isothiazolones substituted at C4 of the phenyl moiety with heterocyclic nucleus or groups of different physico-chemical properties against four human pathogenic fungi was determined by broth macrodilution method; results were compared with those obtained with itraconazole and ketoconazole. These isothiazolones showed moderate to high activity against some or all tested strains and in comparison with the reference drugs, 5-chloro-2-(4-nitrophenyl)isothiazol-3-one (1g), 5-chloro-2-phenylisothiazol-3-one (1c), 4-[4-(5-chloro-3-oxo-3H-isothiazol-2-yl)phenyl]-1,4-dihydrotriazol-5-one (1s) and 2-(4-nitrophenyl)isothiazol-3-one (2g) against Aspergillus niger, 5-chloro-2-(4-nitrophenyl)isothiazol-3-one (1g) and 4-[4-(5-chloro-3-oxo-3H-isothiazol-2-yl)phenyl]piperazine-1-carboxamide (1q) against Trichophyton mentagrophytes had comparable activity, compounds 1g and 2g showing higher activity against Microsporum canis. Antifungal activity was favored by the presence of chlorine at C5 of the isothiazolone and/or the presence of nitro group or heterocyclic nucleus at C4 of the phenyl ring and proper hydrophilicity of the molecule.

Exploration of Physicochemical Properties and Molecular Modeling Studies of Furanylamide Analogs as Antituberculosis Agents

AbstractIn the present study, an attempt has been made to explore physicochemical requirements of furanylamide analogs for binding with Mycobacterium tuberculosis UDP‐galactopyranose mutase. Sequential Multiple Linear Regression (SEQ‐MLR) technique was used for the development of a quantitative structure–activity relationship. The quality of QSAR models obtained from SEQ‐MLR is in acceptable statistical range (explained variance ranging from 77.0 to 91.3%). The statistical qualities of the SEQ‐MLR equations were judged by the parameters like explained variance (r2adj), correlation coefficient (r), Standard Error of Estimate (SEE), and variance ratio (F) at specified Degrees of Freedom (df). The generated equations were internally validated using the leave‐one‐out technique. The selected equations were further validated using a test set considering a predictive squared correlation coefficient (r2pred). The study suggested the indispensable nature of the nitro group on furanylamide scaffold and decisiveness of the van der Waals volume for the activity. The toxicity of the furanylamide analogs might be reduced by limiting the number of hydrogen acceptor groups. The selectivity of the compounds was supported by 3D‐Molecular Representation of Structure based on Electron Diffraction (3D‐MoRSE) code at 24th signal by atomic weight and the presence of nitro group. The binding of furanylamide analogs in M. tuberculosis UDP‐galactopyranose mutase enzyme was explored with the help of docking. The most stable ligand–enzyme complex of compound 2 showed that a ligand binds in the vicinity of the FAD. The nitro group buried in the positive charged pocket, which comprised of Arg‐261 and Lys‐164, depicted the crucial ionic interaction. The phenyl ring of the ligand plays a key role in the hydrophobic interaction by π–π stacking with Tyr‐366 and Tyr‐328.

Synthesis and photodynamic activity of diaryl-porphyrins characterized by the presence of nitro groups

A panel of nitro substituted 5,15-diaryl-porphyrins, featuring nitro groups either on the phenyl rings or on one of the two free meso-positions, was synthesized. In the former category, compounds 5-(3-nitrophenyl)-15-phenylporphyrin, 5,15-di(3-nitrophenyl)porphyrin and 5-(4-nitrophenyl)-15-phenylporphyrin were obtained following standard procedures by reacting dipyrromethane and aromatic aldehydes. In the latter category, porphyrins 10-nitro-5,15-diphenylporphyrin, 10-nitro-5-(3-methoxyphenyl)-15-phenylporphyrin and 10-nitro-5,15-di(3-methoxyphenyl)porphyrin were generated by nitration of 5,15-diarylporphyrins with trifluoroacetic acid/sodium nitrite under particularly mild conditions. The new molecules bearing one or two nitro-groups were tested as photosensitizers during in vitro experiments on a human colon adenocarcinoma cell line (HCT116), and their effects were compared with those induced by temoporfin, porfimer sodium and by some previously published electron-rich diarylporphyrins. The results, expressed as IC50 values obtained by the MTT test following 24 h incubation with the photosensitizers and 2 h irradiation with a 500 W tungsten-halogen lamp, indicate that the presence of an electron withdrawing substituent, on a meso-position, decreases the photodynamic activity of the compound. Conversely, 5-(3-nitrophenyl)-15-phenylporphyrin, a non symmetrically substituted diarylporphyrin bearing both one electron-deficient and one lipophilic moiety, resulted in high phototoxic activity.

Surface Plasmon Resonance Spectroscopy and Electrochemistry Study of 4-Nitro-1,2-phenylenediamine: A Switchable Redox Polymer with Nitro Functional Groups

Electrochemistry and electrochemical surface plasmon resonance (SPR) spectroscopy have been applied to study the electrochemical deposition and the redox transition of poly(4-nitro-1,2-phenylenediamine) (P4NoPD) on gold disk. It was shown that SPR can be the signal transducer for the different redox states of P4NoPD. Using a model biomolecular system, involving streptavidin, biotinylated DNA, and its complementary target DNA, it was found that the presence of nitro groups in P4NoPD allows the biorecognition events to be modulated by voltages. There is minimal nonspecific binding of biomolecules on oxidized (+0.2 V) or as-prepared P4NoPD, and binding occurs more significantly on the reduced P4NoPD (-0.2 to -0.6 V) with the presence of amine groups. The electrochemical deposition of P4NoPD film was also conducted on boron-doped diamond (BDD) electrode. The stability of the reduced P4NoPD film on gold and BDD was comparatively evaluated by electrochemical impedance spectroscopy (EIS). The result showed that BDD allows the electrochemical reduction of the P4NoPD film at wider cathodic limits than gold.

Electrochemical and morphological characterization of poly[( R)-(−)-3-(l-pyrrolyl)propyl- N-(3,5-dinitrobenzoyl)- α-phenylglycinate] films deposited on ITO electrodes

Poly[( R)-(–)-3-(l-pyrrolyl)propyl- N-(3,5-dinitrobenzoyl)- α-phenylglycinate] films were deposited on ITO electrodes using potentiodynamic and galvanostatic methods. Polymerization occurred as a charge dependent process at 1.0 V vs. Ag/Ag +(CH 3CN) and was not affected by the presence of nitro groups in the monomer. The surface morphology of the film and its electrochemical properties were studied as a function of deposition charge ( Q dep) and deposition method. Film thickness increased in a quasi-linear manner with respect to Q dep within the range 40–80 mC cm 2. The galvanostatic method provided easier control of Q dep compared with potentiodynamic deposition, and produced a more adherent film with homogeneous grain geometry. Cyclic voltammetry revealed a well defined redox couple at the anodic region, attributable to polymer p-doping, and a poorly defined redox pair at the cathodic region, attributable to the reduction of the nitro group.

Selective Reduction of the Nitro‐Group Using Co2(CO)8—H2O.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Selective Reduction of the Nitro-group Using Co2(CO)8-H2O

Recently, we reported a new reducing agent prepared from Co2(CO)8 and H2O for the selective 1,4-reduction of α ,βunsaturated carbonyl compounds 1 as well as a tandem reductive Pauson-Khand reaction. 2 We became interested in the reduction power especially the reactivity and the selectivity of this new reducing agent in reducing other functional groups. Reduction of aromatic nitro compounds to amines is a very useful synthetic transformation for which a vast array of reagents has been developed. 3 Though the most general methodology for this conversion is catalytic hydrogenation 4 as it is an economical and effective method, particularly in large scale reactions, the reaction has a limited utility in the presence of other reducible functional groups. 5 The selective reduction of nitro group in presence of other reducible functional groups were also achieved using metal based reduction systems. 6 However, the selective reduction of the nitro group in presence of carbonyl group could not easily be attainable under these conditions. Therefore we became interested in a possibility of the selective reduction of nitro groups in presence of other reducible functional groups including carbonyl groups and halides. Herein, we report that various nitro compounds are selectively and readily reduced to their corresponding amino derivatives in presence of other functional groups. The reaction was tested on p-chloronitrobenzene with the reaction conditions used in the previous report of unsaturated carbonyl compound reduction. 1 Since the nitro group requires more reducing agent than unsaturated carbonyl groups, 2 equivalent of Co 2(CO)8 was used for the reaction with the corresponding amount of water. Dimethoxyethane (DME) was used as the solvent since DME was the optimal solvent for the reduction of the unsaturated carbonyl compounds. To our delight, the reaction completed in 30 minutes and the reaction mixture contained only the desired aniline compound without any trace of other byproducts. When a less amount than 2 equivalent of Co2(CO)8 was used, the reduction was not complete. Then, the reaction was applied to aromatic nitro

The Efficient Synthesis of Azaamino Acids.

AbstractFor Abstract see ChemInform Abstract in Full Text.