4-nitrophenylacetic Acid Research Articles

Synthesis of Oxindoles via SmI2-Promoted Reduction of 2-Nitrophenylacetic Acids

AbstractThe reduction of 2-nitrophenylacetic acids to oxindoles promoted by SmI2 is reported for the first time. This reaction involving the reduction of nitro group proceeds through N–O bond cleavage and direct condensation with the neighboring carboxyl group. From a synthetic point of view, a new method for the synthesis of oxindoles in mild neutral conditions is developed.

2D-3D supramolecular assemblies containing 2-amino-4,6-dimethoxypyrimidine and carboxylic acids: Preparation, crystallographic characterization, and Hirshfeld surface analysis

Eight crystals (1–8) derived from various substituted carboxylic acids of 2-pyrazinecarboxylic acid, 3,4-methylenedioxybenzoic acid, 4‑hydroxy-3-nitrobenzoic acid, 4‑chloro-2-nitrobenzoic acid, mandelic acid, 4-nitrophenylacetic acid, 3,4,5-trimethoxycinnamic acid, and itaconic acid and 2-amino-4,6-dimethoxypyrimidine (admpm) were prepared and identified, and further characterized thoroughly with single crystal X-ray diffraction (SCXRD), and elemental analysis techniques. The melting points were also measured. Significant non-covalent interactions were calculated by means of the Hirshfeld surface analysis. Among the eight crystals, proton transfer from the carboxylic acid to ring N of the pyrimidine has occurred only at 1, while the remaining ones 2–8 were co-crystals. It is obvious that the R22(8) ring motif occurs in all cases when a carboxyl unit interacts with a pyrimidine base. The present work surely indicates that there are two main associate modes between the 2-amino-4,6-dimethoxypyrimidine and the carboxylic acids, which regularly occur, linear heterotetramer (LHT), and cyclic heterotetramer (CHT). Here, LHT is dominant as it occurs in 5/8 frequency (at 3–4 and 6–8), CHT in 2/8 (at 1–2), with the remaining one structure (5) forming a heterodimer. The heterotrimer (HT) was not established in this test. Thus LHT is more stable than CHT and other synthons.

Rapid evaluation of the substrate specificity of 3-nitrobenzoic acid dioxygenase MnbAB via colorimetric detection using Saltzman reagent.

Nitroaromatic compounds are essential materials for chemical industry, but they are also potentially toxic environmental pollutants. Therefore, their sensitive detection and degradation are important concerns. The microbial degradation pathways of nitroaromatic compounds have been studied in detail, but their usefulness needs to be evaluated to understand their potential applications in bioremediation. Here, we developed a rapid and relatively sensitive assay system to evaluate the activities and substrate specificities of nitroaromatic dioxygenases involved in the oxidative biodegradation of nitroaromatic compounds. In this system, nitrous acid, which was released from the nitroaromatic compounds by the dioxygenases, was detected and quantified using the Saltzman reagent. Escherichia coli producing the 3-nitrobenzoic acid dioxygenase complex MnbAB from Comamonas sp. JS46 clearly showed the apparent substrate specificity of MnbAB as follows. MnbAB accepted not only 3-nitrobenzoic acid but also several other p- and m-nitrobenzoic acid derivatives as substrates, although it much preferred 3-nitrobenzoic acid to others. Furthermore, the presence of a hydroxy or an amino group at the ortho position of the nitro group decreased the activity of MnbAB. In addition, MnbAB accepted 2-(4-nitrophenyl)acetic acid as a substrate, which has one additional methylene group between the aromatic ring and the carboxy group of 3-nitrobenzoic acid. This is the first report about the detailed substrate specificity of MnbAB. Our system can be used for other nitroaromatic dioxygenases and contribute to their characterization.

Equilibrium Solubility and Dissolution Property Analysis of 2-Nitrophenylacetic Acid in 13 Pure Solvents at Elevated Temperatures

This work was devoted to the equilibrium solubility of 2-nitrophenylacetic acid in 13 neat solvents ethylene glycol (EG), methanol, ethanol, acetonitrile, n-propanol, isopropanol, water, n-butanol, N,N-dimethylformamide (DMF), isobutanol, cyclohexane, ethyl acetate, and 1,4-dioxane ranging from 283.15 to 328.15 K. All determinations were made by the shake-flask technique at a pressure of p = 101.2 kPa. The mole fraction solubility magnitudes of 2-nitrophenylacetic acid increased gradually with the rising investigated temperature and presented a decreasing trend in the 13 neat solvents: DMF > (1,4-dioxoane, methanol) > ethanol (ethyl acetate) > n-propanol > n-butanol > isopropanol > EG > acetonitrile > isobutanol > water > cyclohexane. The method of linear solvation energy relationships was employed here to inspect the solvent–solvent and solute–solvent interactions. The solvent descriptors of the Hildebrand solubility parameter and polarizability/dipolarity presented great influence upon the solubility magnitudes of the solute 2-nitrophenylacetic acid. The obtained solubility values in mole fraction were correlated mathematically via four models/equations, namely, λh, non-random two-liquid, Apelblat, and Wilson. The maximum value of relative average deviation (RAD) was 3.68 × 10–2, and the maximum value of root-mean-square deviations was 116.78 × 10–4. The RAD values by using the Apelblat equation were smaller than that by using the other equations/models for a fixed solvent. Additionally, the dissolution properties, activity coefficient, and reduced excess enthalpy under the conditions of infinite dilution were obtained through the Wilson model.

The electrochemical behavior of 4-nitrobenzyl bromide and its catalytic activity for reduction of CO2 in the acetonitrile solvent at the Cu/Pd/rGO/GCE surface

In this study, 4-nitrobenzyl bromide was used as a catalyst for reduction of CO2 and as an initial substrate for electrosynthesis of 4-nitrophenylacetic acid. Cu nanoparticles/Pd nanoparticles/reduced graphene oxide nanocomposite modified glassy carbon electrode (Cu/Pd/rGO/GCE) was used to promote electroactivation of CO2. rGO film was fabricated via electrochemical reduction of dispersed GO nanosheets on the GCE surface. Cyclic voltammetry procedure was applied in two steps to deposit Pd and Cu nanoparticles on the rGO/GCE surface. The morphology and structure of the nanocomposites were characterized using FESEM, EDS, AFM and XRD analysis. FTIR, 1H and 13C NMR spectral characteristics were used to identify the final products of the catalytic process. The electrocarboxylation of 4-nitrobenzyl bromide occurs at a potential which is less negative than those reported for other aryl halides. The results indicate that 4-nitrobenzyl bromide, as a catalyst, plays a dual role in the electrosynthesis of 4-nitrophenylacetate. The dual role includes the electrocatalytic reduction of CO2 and reaction of produced CO2•− with 4-nitrobenzyl bromide radical anion. Finally, an EC’C mechanism is proposed for the electrosynthesis of 4-nitrophenylacetate.

Solubility Modeling, Solvent Effect, and Dissolution Properties of 4-Nitrophenylacetic Acid in Thirteen Solvents Ranging from 283.15 to 328.15 K

Solubility of 4-nitrophenylacetic acid in 13 neat solvents of n-propanol, methanol, ethylene glycol (EG), ethanol, isopropanol, cyclohexane, acetonitrile, N,N-dimethyl formamide (DMF), N,N-dimethyl...

Synthesis, characterization, structural elucidation, electrochemistry, DNA binding study, micellization behaviour and antioxidant activity of the Cu(II) carboxylate complexes

New dimeric paddlewheel copper(II) mixed ligand complexes were synthesized having general formulae [(py)Cu(L)4Cu(py)] (1), [(clpy)Cu(L*)4Cu(clpy)] (2) and [(py)Cu(L°)4Cu(py)] (3) where HL = 4-bromophenylacetic acid, HL* = phenyl acetic acid, HL° = 2-nitrophenylacetic acid, py = pyridine, clpy = 2-chloropyridine and characterized via FT-IR, powder and single crystal XRD, electrochemical solution studies and electron spin resonance spectroscopy. The resultant structures are dimeric paddlewheel where the carboxylate ligands act as bridges between two copper ions and pyridine acts as apical ligand leading to a square pyramidal geometry around each copper. The purity and crystalline nature of the complexes was checked by powder XRD technique. ESR spectra of the copper(II) complexes gave a sharp peak with g values = 1.443 (1) 1.512 (2) and 1.391 (3). The electrochemical studies showed diffusion controlled processes with diffusion co-efficient Do values = 3.68 × 10−6 cm2s−1 (1) and 3.63 × 10−6 cm2s−1 (3). Moreover, the complex-DNA interaction was studied by viscosity measurement, spectrofluorometry, cyclic voltammetry and UV–Visible spectrophotometry, the latter two yielding binding constant, Kb values = 4.0497 × 104 M−1 and 1.703 × 104 M−1 (1) and 4.117 × 104 M−1 and 1.743 × 104 M−1 (3), respectively. The complexes 1 and 2 showed moderate scavenging activity for the radical 2,2-diphenyl-1-picryl-hydrazil. Micellization behaviour was studied with cationic surfactant CTAB using conductivity meter and UV–Visible spectrophotometer showing that all the complexes have increased solubility with the addition of surfactant. These initial studies heralded good biological potential of the complexes.

Ti-Catalyst Biomimetic Sensor for the Detection of Nitroaromatic Pollutants.

An electrode modified by a Ti complex in Nafion was used in the electrochemical detection of nitroaromatic compounds (NACs). The catalyst reduced nitroaromatic groups by a six-electron process with a high apparent rate constant, k1, which was estimated to be at least 19 000 mol-1 L s-1 by simulation of the first step of the cathodic reduction of 4-nitrophenylacetic acid, which was used as model molecule. The modified electrode was prepared and optimized in terms of Nafion and catalyst concentrations. In the chosen analytical medium, the Ti-catalyst-containing electrode showed good stability in the presence of nitro species. A standard deviation around 15% was calculated on the analysis performed with 28 different modified electrodes, which could be expected for a drop-coating process. We show that the modified electrode detects several nitroaromatic compounds such as nitrophenols, mononitroaniline, and dinitrotoluene with detection limits ranging from 1 × 10-4 to 9 × 10-4 g L-1 (0.2 × 10-6 to 5.1 × 10-6 mol L-1). As an interesting feature, the sensor exhibits good selectivity toward NAC detection because titanocene does not catalyze the reduction of nitroaliphatic compounds.

4-Нитрофенилацетаты тетра- и три-(пара-толил)сурьмы. Синтез и особенности строения

The interaction of penta( para -tolyl)antimony with 4-nitrophenylacetic acid in toluene have synthesized tetra( para -tolyl)antimony 4-nitrophenylacetate ( 1 ). The reaction of tri( para -tolyl)­antimony with tert -butyl hydroperoxide and 4-nitrophenylacetic acid in diethyl ether leads to the formation of tri( para -tolyl)antimony bis (4-nitrophenylacetate) ( 1 ). The X-ray diffraction pattern has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (Mo K α -radiation, λ = 0.71073 Å, graphite monochromator) of crystals 1 [C 72 H 68 N 2 O 8 Sb 2 , M 1332.78, the triclinic syngony, the symmetry group P –1; cell parameters: a 12.08(3), b 16.46(3), c 17.79(3) Å, α = 107.61(7) degrees, β = 97.20(10) degrees, γ = 101.94(9) degrees; V = 3229(11) Å 3 ; the crystal size is 0.51×0.24×0.17 mm; intervals of reflection indexes are –10 ≤ h ≤ 10, –14 ≤ k ≤ 14, –15 ≤ l ≤ 15; total reflections 14622; independent reflections 4546; R int 0.0697; GOOF 1.072; R 1 = 0.0585, wR 2 = 0.1688; residual electron density 0.75/–0.85 e/Å 3 ] and 2 [C 37 H 33 O 8 N 2 Sb, M 755.40, the monoclinic syngony, the symmetry group P2 1 /n ; cell parameters: a 9.271(2), b 28.413(7), c 13.604(3) Å, α = 90.00 degrees, β = 105.876(2) degrees, γ = 90.00 degrees; V = 3425.5(13) Å 3 ; the crystal size is 0.95×0.58×0.34 mm; intervals of reflection indexes are –16 ≤ h ≤ 16, –50 ≤ k ≤ 50, –24 ≤ l ≤ 24; total reflections 125931; independent reflections 20517; R int 0.0450; GOOF 1.114; R 1 = 0.0511, wR 2 = 0.0993; residual electron density 0.70/–0.97 e/Å 3 ] the antimony atoms have distorted trigonal-bipyramidal coordination. The axial angles of OSbC and OSbO are 177.9 (5)°, 177.9 (5) ° ( 1 ) and 177.27(5)° ( 2 ); the sum of the angles of CSbC in the equatorial plane is 356.9°, 357.6° ( 1 ), 359.79° ( 2 ). The Sb–O and Sb–C bond lengths are 2.1443(15)–2.269(10) Å and 2.098(15)–2.170(14) Å. The structural organization of crystals 1 and 2 is controlled by intermolecular bonds O···H (2.46–2.67 Å). Complete tables of coordinates of atoms, bond lengths and valence angles for structures 1 and 2 are deposited at the Cambridge Structural Data Bank (no. 1819287, 1819295; deposit@ccdc.cam.ac.uk; http: //www.ccdc. Cam.ac.uk).

Quantum chemical calculation (RDG) of molecular structural evaluation, Hirshfeld, DSSC and docking studies of 4-nitrophenylacetic acid

4-Nitrophenylacetic acid (NPA) was recorded and analyzed using FT-IR and FT-Raman spectra. The theoretical vibrational frequencies were carried out with the help of quantum chemical calculations. The electron density based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or the reactivity site in the NPA. Natural bond orbital analysis of first and second hyperpolarizability and frontier molecular orbital are also reported. The molecular electrostatic potential map was used to detect the possible electrophilic and nucleophilic sites in the molecule. The various intermolecular interactions and their importance were explained using the Hirshfeld surface analysis. The reduced density gradient of the title molecule was investigated by the interaction of molecule. Molecular docking studies were also described.

The spontaneous decarboxylation of strong carboxylic acid − carboxylate mixtures and the use of carbon surfaces to trap the released free radicals

The mechanism of the spontaneous decomposition of a mixture of 4-nitrophenylacetic acid (NO2BzCOOH) with its respective tetrabutylammonium carboxylate in acetonitrile (NO2BzCOO−) was analyzed using cyclic voltammetry, atomic force microscopy, nuclear magnetic resonance and electronic structure calculations. This reaction is favoured by the high acidity of the carboxylic acid and occurs following a decarboxylation loop where the carboxylate anion has the function of reductant whereas the acidic proton of the carboxylic acid acts as oxidant. This redox reaction allows the generation of hydrogen as well as an acyloxy radical, that after cleavage, yields 4-nitrobenzyl radicals that have the possibility to react either in solution to produce 4-nitrotoluene or react with a carbon surface to produce a covalently modified layer with 4-nitrobenzyl groups.

A comparative structural and property investigation of four new bivalent transition metal complexes based on 4-nitrophenylacetic acid with rigid 4-nitrobenzoate analogues

The synthesis, spectral, thermal, magnetic properties, and structural features of four new one-dimensional (1-D) polymers having formula [M(4-npa)2(μ2-H2O)(H2O)2]·2H2O where (M=Mn 1; M=Co 2; M=Zn 3; M=Ni 4; 4-npa=4-nitrophenylacetate) are investigated and compared with corresponding 4-nitrobenzoate (4-nba) analogues. The single crystal studies reveal that compounds 1–3 are isostructural and crystallize in the centrosymmetric monoclinic space group P21/c. Their structure consists of distorted octahedra of a unique central metal ion, two crystallographically unique monodentate 4-npa ligands, two terminal water molecules, a μ2-bridging bidentate water and two lattice water molecules. The central metal exhibits a distorted {MO6} octahedron with two O atoms from terminal water molecules disposed cis to each other, two O atoms from the monodentate carboxylates also disposed in a cis geometry and the remaining two O atom from the μ2-bridging bidentate water disposed trans. The μ2-brindging mode of water leads to the formation of an extended 1-D chain structure. The lattice water links parallel 1-D chains with the aid of H-bonding interactions. The IR, XRD powder pattern, thermal characterization and elemental analysis reveal that the structure of polycrystalline compound 4 is nearly identical with that of other 4-npa analogues.

Decomposition of Strong Carboxylic Acids Redox Catalyzed By Carboxylate Ions; Chemical Grafting of Carbon Surfaces

In mixtures of trichloroacetate ion and trichloroacetic acid in acetonitrile, trichloromethyl radicals are produced as a result of the redox reaction between the acid and its conjugated base. The reaction follows a loop mechanism in which the trichloroacetic acid is slowly consumed by proton reduction while the trichloroacetate ion is oxidized like in an electrochemical Kolbe reaction [1]. The hydroquinone-trichloroacetate complex was a good sensor of this unexpected self-decarboxylation redox reaction [2]. According to the conceptual framework of this reaction, the acid-base mixture was also tested but using the compounds derived from 4-nitrophenylacetic acid. The reaction ocurrs also in this system, however, when a glassy carbon electrode was present in the reaction solution, the grafting of nitrobenzyl groups on the surface was detected, whereas 4-nitrotoluene was detected as the product of a paralel reaction in solution. Therefore, the reaction represent an alternative to the covalent modification of carbon substrates without electrochemical induction.[1] Drochss P. Valencia, Pablo D. Astudillo, Annia Galano, Felipe J. González, Org. & Biomol. Chem., 2013, 11, 318-325 [2] Pablo D. Astudillo, Annia Galano, Jorge Tiburcio, Felipe J. González, J. Electroanal. Chem., 2007, 604, 57-64 Figure 1

Microwave assistant synthesis of trans-4-nitrostilbene derivatives in solvent free condition

A general method for the synthesis of trans-4-nitrostilbenes has been developed. The trans-4-nitrostilbene could be synthesized in good yields under microwave irradiation within 10 min through Perkin reaction by using 4-nitrophenylacetic acid, benzaldehydes and pyrrolidine.

A safe and selective method for reduction of 2-nitrophenylacetic acid systems to N-aryl hydroxamic acids using continuous flow hydrogenation

The cyclic hydroxamic acid functional group is critical to the biological activity of numerous natural products and drug candidates. Efficient, reliable, and green synthetic methods to produce cyclic hydroxamic acids are needed. Herein, flow hydrogenation has been explored as a novel approach toward achieving the selective partial reduction of 2-nitrophenylacetic acid to 1-hydroxyindolin-2-one. The bidentate ligand, 1,10-phenanthroline, has been identified as a unique inhibitor for modulating product selectivity in this Pt/C-catalyzed process. Under the newly optimized reaction conditions, the targeted hydroxamic acid is produced with high selectivity (49:1) over the lactam by-product. The scope of the reaction is demonstrated for a variety of 2-nitrophenylacetic acid derivatives.

A monoclinic polymorph of 2-(4-nitrophenyl)acetic acid

A new monoclinic form of 4-nitrophenylacetic acid, C8H7NO4, (I), differs from the known orthorhombic form both in its molecular conformation and in its intermolecular contacts. The conformation is different as the plane of the carboxylic acid group in (I) is more nearly perpendicular to the plane of the aromatic ring [dihedral angle = 86.9 (3)°] than in the previous form (74.5°). Both polymorphs display hydrogen-bondedR22(8) carboxylic acid dimeric pairs, but in (I), neighbouring dimers interact through nitro–nitro N...O dipole–dipole contacts rather than the nitro–carbonyl contacts found in the orthorhombic form.

Syntheses, structure and properties of Alkaline-earth metal salts of 4-Nitrophenylacetic acid

The synthesis, crystal structure, spectral characteristics and thermal properties of alkaline-earth metal salts of 4-nitrophenylacetic acid (4-npaH) namely, [Mg(H2O)6](4-npa)2⋅4H 2O (4-npa = 4-nitrophenyl-acetate) (1), [Ca(H 2O) 2(4-npa) 2] (2) and [Sr(H 2O) 3(4-npa) 2] ⋅4.5H 2O(3) are reported. In 1, the 4-npa ion functions as a charge balancing counter anion for the octahedral [Mg(H 2O) 6] 2+ unit with the Mg(II) ion situated on a centre of inversion. The two unique lattice water molecules link the [Mg(H 2O) 6] 2+ cations and 4-npa anions with the aid of O-H ⋯O interactions. Compounds 2 and 3 are one-dimensional (1-D) coordination polymers containing an eight coordinated Ca(II) situated in a general position and a nine coordinated Sr(II) located on a twofold axis. The μ 2-bridging tridentate binding modes of the crystallographically independent 4-npa ligands in 2 and the unique 4-npa ligand in 3 link the bivalent metal ions into an infinite chain with alternating Ca ⋯Ca separations of 3.989 and 4.009 Å, respectively, and a single Sr ⋯Sr separation of 4.194 Å in the 1-D chain. Synthesis, structure and properties of [Mg(H2O)6](4-npa)2·4H2O (4-npa =4-nitrophenylacetate) (1), [Ca(4-npa)2(H2O)2] (2), and [Sr(4-npa)2(H2O)3]·4.5H2O (3) are reported.

Development of Sensor Surfaces Using Poly-(N-vinylformamide) for Sensitive Detection of 2,4,6-Trinitrotoluene by Displacement Method on a Surface Plasmon Resonance Sensor

To detect 2,4,6-trinitrotoluene (TNT) using a displacement method over a surface plasmon resonance immunosensor, we developed sensor surfaces modified with a poly-(N-vinylformamideco-vinylamine), which was synthesized from a monomer, N-vinylformamide, and was hydrolyzed to produce amine groups, and TNT analogs. Poly-(N-vinylformamide-co-vinylamine) that reacted with succinic acid was used as a matrix of a sensor surface for increasing the number of antibody binding sites. 2,4-Dinitrophenyl glycine, 3-nitrophenyl acetic acid, and 4-nitrophenyl acetic acid were immobilized on the polymer-modified sensor surfaces. We evaluated the suppression ability of the sensor surface for nonspecific adsorption and determined the limit of detection (LOD) for TNT. As a result, a sensor chip suppressed nonspecific adsorption for 1 mg/mL bovine serum albumin and lysozyme. TNT was measured by the displacement method, and the LOD achieved over a 3-nitrophenyl acetic acid-modified sensor chip was 0.9 ng/mL (ppb).

Synthesis, spectroscopic characterization and structural investigation of a new charge transfer complex of 2,6-diaminopyridine with 4-nitrophenylacetic acid: Antimicrobial, DNA binding/cleavage and antioxidant studies

A new hydrogen-bonded charge-transfer complex (CT) formed by the reaction between donor, 2,6-diaminopyridine and acceptor, 4-nitrophenylacetic acid in methanol at room temperature. The crystal was characterized by elemental analysis, IR, NMR spectroscopic studies and thermal studies. The elemental analysis of CT complex, obtained data revealed that the formation of 1:1 ratio CT complex was proposed. Infrared and NMR studies confirm the chemical constituents and molecular structure of the synthesized complex crystal. The high thermal stability is due to the molecular frame work through H-bonding interactions. Structural investigation indicates that cation and anion are linked through strong N+–H⋯O− type of hydrogen bond. The hydrogen bonded charge transfer crystal was screened for its pharmacology, such as antimicrobial, DNA binding/cleavage and antioxidant studies. The CT complex was screened for its antibacterial and antifungal activity against various bacterial and fungal species, which shows good antimicrobial activity. The DNA binding results indicated that the compound could interact with DNA through intercalation. It should have weak to moderate capacity of scavenging with DPPH.

Synthesis and crystal structure of a polymeric zinc(II) complex derived from 4-nitro- phenylacetic acid and propane-1,3-diamine

A new polymeric zinc(II) complex, [ZnL 2 (PDA)] n , has been prepared by the reaction of zinc sulfate, 4-nitrophenylacetic acid, and propane-1,3-diamine (PDA) in water. Structure of the complex has been characterized by single-crystal X-ray diffraction. The complex crystallizes as orthorhombic space group Pnma , with unit cell dimensions a = 15.732(1) A, b = 23.912(1) A, c = 5.5565(3) A, V = 2090.2(2) A 3 , Z = 4, R 1 = 0.0427, wR 2 = 0.0968, S = 1.048. The Zn atom is coordinated in a tetrahedral geometry. Single crystals of the complex are stabilized by hydrogen bonds and p···p interactions. KEY WORDS : 4-Nitrophenylacetic acid, Zinc complex, Crystal structure, Hydrogen bonding Bull. Chem. Soc. Ethiop. 2014 , 28(2), 315-319. DOI: http://dx.doi.org/10.4314/bcse.v28i2.17