Presence Of Aniline Research Articles

Catalytic Reactions of Homo- and Cross-Condensation of Ethanal and Propanal

Processes of catalytic homocondensation of propanal and its cross-condensation with ethanal and methanal in the presence of aniline and amino acids have been studied. The dependence of the conversion of the reactants and selectivity of the homo/heterocondensation process on the catalyst nature and temperature has been revealed. It has been shown that the maximum acrolein selectivity is reached in the case of using benzoyl-substituted derivatives in water, with the proportion of the products of further condensation decreasing. The selectivity for the ethanal homocondensation product 2-butenal decreases simultaneously as a result of the formation of linear and branched oligomers of successive condensation.

Discovery of a Biologically Active Bromodomain Inhibitor by Target-Directed Dynamic Combinatorial Chemistry.

Target-directed dynamic combinatorial chemistry (DCC) has emerged as a strategy for the identification of inhibitors of relevant therapeutic targets. In this contribution, we use this strategy for the identification of a high-affinity binder of a parasite target, the Trypanosoma cruzi bromodomain-containing protein TcBDF3. This protein is essential for viability of T. cruzi, the protozoan parasite that causes Chagas disease. A small dynamic library of acylhydrazones was prepared from aldehydes and acylhydrazides at neutral pH in the presence of aniline. The most amplified library member shows (a) high affinity for the template, (b) interesting antiparasitic activity against different parasite forms, and (c) low toxicity against Vero cells. In addition, parasites are rescued from the compound toxicity by TcBDF3 overexpression, suggesting that the toxicity of this compound is due to the TcBDF3 inhibition, i.e., the binding event that initially drives the molecular amplification is reproduced in the parasite, leading to selective toxicity.

Copper-catalyzed oxidative synthesis of 2-oxo-acetamidines from one-pot three-component reaction of aryl methyl ketones, secondary amines and anilines

Some novel 2-oxo-acetamidines were synthesized via one-pot three-component reaction of acetophenones, secondary amines and anilines in presence of CuI as catalyst. The reaction involved in a oxidation process of C (sp3)H bonds of acetophenones in presence of air followed by aminations, and products were obtained in good to excellent yields (70–82%) in simple work-up procedure.

Synthesis, spectroscopic, thermal analyses and biological activity evaluation of new zirconium(IV) solid complexes with bidentate lomefloxacin

Four metal complexes of antibacterial agent lomefloxacin (LFX) with zirconium(IV) in the presence of aniline (An), pyridine (Py) and o-tolidine (o-Tol) as nitrogen donor molecules and dimethyl formamide (DMF) as oxygen donor molecule have been prepared and characterized with physicochemical and diverse spectroscopic techniques (IR, UV-Vis. and 1H NMR spectroscopes) as well as thermal analysis. The deprotonated lomefloxacin complexes of Zr(IV) were isolated as solids with the general formula, [ZrO(LFX)2L]Cl2,where L = An, Py, o-Tol and DMF. The infrared spectral data show the chelation behavior of LFX toward Zr(IV) through oxygen of pyridone, one oxygen of carboxylic group and complete the coordination number with nitrogen or oxygen atom of L. The thermodynamic parameters are calculated from the thermal analysis curves using the Coats–Redfern and Horowitz–Metzger methods. The antibacterial of LFX and their Zr(IV) complexes were also evaluated for their antibacterial activity against three Gram (+Ve) and three Gram (-Ve) microorganisms.

Synthesis of Benzothiazolyl Guanidinyl Derivatives and their In-Vitro Antimicrobial and Antioxidant Activity

Background: Compounds containing CN3 groups are named as guanidine derivatives, which have a rich history in biological and bio-inspired activity. Many guanidine moieties are reported for the antimicrobial activity. Present study aims to the enhancement of bio-activity of the guanidine subunits by conjugating with benzothiazole. Methods: A new series of benzothiazole guanidines have been synthesized from the reaction of thiourea derivatives of 6-substituted benzothiazoles with different substituted anilines in presence of HgCl2. The synthesized compounds were characterized through FT-IR, mass and 1H NMR spectral techniques. The synthesized compounds were screened for the Antimicrobial activity by disc diffusion method and antioxidant activity was assigned by DPPH and ABTS assay. Results: The products were screened for antimicrobial activity. They were found to exhibit moderate to potent activity against the tested microorganisms and have shown minimum inhibition concentration of 1.56 µg/mL for Candida albicans, 0.78 µg/mL for Aspergillus niger, 25 µg/mL for S. aureus and 12.5 µg/mL for E. coli. The derivatives were also tested for antioxidant DPPH and ABTS assays and they were found to have significant activities compared to the standards. Conclusion: In the present work, a new series of benzothiazole guanidinyl derivatives were synthesized in good yields by employing HgCl2 reagent. Synthesized compounds were screened for antimicrobial and antioxidant activities and compounds containing p-methoxy, o-hydroxy showed better antioxidant activities and antimicrobial activities.

Rapid formation of aniline-degrading aerobic granular sludge and investigation of its microbial community succession

Aniline is one of common by-products in several industries such as petroleum and chemical and its discharge attracts increasing concern in recent years. Aerobic granular sludge (AGS) technology is regarded as one of the most promising biological processes. However, there are some drawbacks such as long start-up especially when the system is fed with toxic pollutants (e.g., aromatic compounds). In this study, rapid formation of AGS for aniline biodegradation was investigated. The aerobic granules were successfully developed in a sequencing batch airlift reactor (SBAR) fed with aniline-containing wastewater within 15 days. The sludge volume index decreased from 58.47 to 30.31 mL g−1 after AGS was formed. It was also found that extracellular polymeric substances (EPS) especially protein was increased significantly during aerobic granulation. Besides, the average removal efficiencies of aniline and COD from day 3–15 (the period since early observation of pinpoint particles in the mixed liquor) were 99.93% and 90.59%, respectively. NH4+-N was also remarkably reduced in the SBAR. Through pyrosequencing analysis, Proteobacteria was the most abundant phylum during granulation. There were several genera responsible for aniline biodegradation and EPS secretion such as Pseudomonas was found to be predominant in the system. The rapid formation of AGS and high removal efficiency of aniline and COD in the present system might provide an alternative for treating industrial effluents with presence of aniline.

Target-directed Dynamic Combinatorial Chemistry: A Study on Potentials and Pitfalls as Exemplified on a Bacterial Target.

Target-directed dynamic combinatorial chemistry (DCC) is an emerging technique for the efficient identification of inhibitors of pharmacologically relevant targets. In this contribution, we present an application for a bacterial target, the lectin FimH, a crucial virulence factor of uropathogenic E. coli being the main cause of urinary tract infections. A small dynamic library of acylhydrazones was formed from aldehydes and hydrazides and equilibrated at neutral pH in presence of aniline as nucleophilic catalyst. The major success factors turned out to be an accordingly adjusted ratio of scaffolds and fragments, an adequate sample preparation prior to HPLC analysis, and the data processing. Only then did the ranking of the dynamic library constituents correlate well with affinity data. Furthermore, as a support of DCC applications especially to larger libraries, a new protocol for improved hit identification was established.

A DFT-based mechanistic study on the formation of oximes

Oxime chemistry has been proven to be a reliable bioconjugation method for biomedical applications. Because of its stable and bio-orthogonal nature, a number of materials have been devised for in vitro and in vivo applications such as drug delivery, imaging, and biochemical assays. Polymers, synthetic molecules, nanoparticles, and biomolecules carrying alkoxyamine and aldehyde/ketone functional groups could be linked to each other through oxime bond, and a variety of modular platforms could be produced. Formation of oximes is catalyzed in acidic medium, and the proposed reaction mechanism follows classical imine formation pathways. Aniline has been found to accelerate the rate of oxime formation several orders of magnitude. In this computational study, we analyzed the proposed mechanism on model systems using DFT calculations including a solvation model. The energetics of the reaction steps in neutral and acidic conditions as well as in the presence of aniline was performed. Explicit water molecules were included in the calculations to study the energetics of solvent assisted proton transfer steps.

A new route to N-aromatic heterocycles from the hydrogenation of diesters in the presence of anilines.

The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ε-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield.

Synthesis, Characterization of Substituted (4-Oxo-3-Phenyl-3,4-Dihydro Quinazolin-2-yl)Methyl Nitrite Derivatives and Evaluation of their Antimicrobial Activity

Synthesis of substituted (4-oxo-3-phenyl-3,4-dihydro quinazolin-2-yl)methyl nitrite derivatives[5(a-j)] have been prepared oxidation reaction of 6-chloro-2-(chloromethyl)-3-[phenyl] quinazolin-4(3H)-one(4) with AgNO3. Compound (5) prepared from starting meterial are 5-chloro-2-[(chloroacetyl)amino]benzoic acid (1) is undergoes to cyclization with acetic anhydride to form 5-chloro-2-[(chloroacetyl)amino]benzoic acid (2) in yield 72%. 5-chloro-2-[(chloroacetyl) amino]benzoic acid(2) undergoes ro cyclisation with acetic anhydride under reflux conidition to form 6-chloro- 2-(chloromethyl)-4H-3,1-benzoxazin-4-one (3) now this compound have been reacted with glycial acetic acid in presence of aniline to form 6-chloro-2-(chloromethyl)-3-[phenyl] quinazolin-4(3H)-one(4). Chareterization done by 1H-NMR, 13C-NMR, IR, MASS spectral analysis. Evaluation of antibacterial activity by Gram-positive bacteria viz. Bacillus subtilis, Bacillus sphaericus and Staphylococcus aureus and three Gram-negative bacteria viz. Pseudomonas aeruginosa, Klebsiella aerogenes and Chromobacterium violaceum and antifungal activity against Candida albicans, Aspergillus fumigates, Trichophyton rubrum and Trichophyton mentagrophytes. Most of the compounds are exihibits more potential activity.

Catalytic performance and electrochemical behaviour of Metal–organic frameworks: MIL-101(Fe) versus NH2-MIL-101(Fe)

The present research investigation brings out a novel and relevant catalytic application for the family of MIL-101 metal–organic framework (MOF) materials. The porous Fe(III) terephthalate MOF, MIL-101(Fe) and the corresponding amino-functionalized material, NH2-MIL-101(Fe) showed to be highly active and 100% selective heterogeneous catalysts in the ring opening of cyclohexene oxide in the presence of aniline. The activity of both MOF materials was similar, mainly after 24h, achieving yields of 87% for trans-2-(phenylamino)-cyclohexanol. The stability and robustness of these MOF materials were confirmed and their capacity to be recycled was also demonstrated. Furthermore, cyclic voltammetry studies revealed that the amine-functionalization of the MIL-101(Fe) results in a significant improvement of the electrochemical response over the unfunctionalized compound, constituting an exceptional advantage of the NH2-MIL-101(Fe) as a future potential electrocatalyst.

Synthesis, thermal analyses, characterization and biological evaluation of new enrofloxacin vanadium(V) solvates(L) (L = An, DMF, Py, Et3N and o-Tol)

Five metal complexes of antibacterial agent enrofloxacin with vanadium(V) in the presence of aniline, pyridine, orthotolidine and triethylamine as nitrogen donor molecules and dimethylformamide as oxygen donor molecule have been prepared and characterized with physicochemical and diverse spectroscopic techniques (IR, UV–Vis. and 1H NMR spectroscopes) as well as thermal analysis. The deprotonated enrofloxacin complexes of V(V) were isolated as solids with the general formulas; [VO(Enr)2DMF]Cl·5H2O, [VO(Enr)2An]Cl·2H2O, [VO(Enr)2o-Tol]Cl·H2O, [VO(Enr)2Py]Cl·4H2O and [VO(Enr)2Et3N]Cl·6H2O. The prepared complexes are formed with a metal to ligand ratios as 1:2:1 for all complexes. The lowest energy model structure of each complex has been proposed by using the density functional theory (DFT) at the B3LYP/CEP-31G level of theory. The energy barrier for the pyridine complex greater than others complexes while, Et3N complex has lower value. The ligand and their metal complexes were also evaluated for their antibacterial activity against three Gram (+ve) and three Gram (−ve) microorganisms.

Route to High Surface Area, Mesoporosity of Polyaniline–Titanium Dioxide Nanocomposites via One Pot Synthesis for Energy Storage Applications

This paper reports the synthesis of mesoporous polyaniline–titanium dioxide (Pani–TiO2) nanocomposites via a one pot approach in the presence of aniline and titanium iso-propoxide precursor under ice bath conditions. Scanning and transmission electron microscopy showed that the Pani–TiO2 was mesoporous in nature. BET analysis revealed the Pani–TiO2 to have a 2-fold higher surface area than Pani. The shift of the peaks in the FTIR and XRD pattern showed that TiO2 had perfectly intercalated into the Pani matrix, which suggests a strong interaction between Pani and TiO2. The electrochemical properties of Pani and the mesoporous Pani–TiO2 were examined by cyclic voltammetry and charge/discharge studies. The mesoporous Pani–TiO2 electrode exhibited a high specific capacitance of 935 F g–1 at 1 A g–1 current density. The mesoporous Pani–TiO2 displayed excellent cyclic stability up to 2000 cycles and delivered a high energy density of 94.8 Wh kg–1 at a 977 W kg–1 power density.

Condensation of Diacetyl with Alkyl Amines: Synthesis and Reactivity of p-Iminobenzoquinones and p-Diiminobenzoquinones.

Condensation reactions between diacetyl and α-branched primary alkylamines under mild and neutral conditions provided a mixture of 2,5-dimethylbenzoquinone(alkylimines), 2,5-dimethylbenzoquinone(bis-alkyldiimines), and N,N′-dialkyl-2,5-dimethylbenzene-1,4-diamines, which were efficiently separated as pure products by column chromatography. Both 2,5-dimethylbenzoquinone(alkylimines) and 2,5-dimethylbenzoquinone(bis-alkyldiimines) underwent an interchange of the alkylimino group when treated with anilines, followed by reductive aromatization, to provide diarylamines and 1,4-dianilinobenzenes, respectively. Evaluation was also made of the reactivity and selectivity of these compounds in the presence of anilines, thiophenols and alkylhalides.

Nickel(II) complexes having Imidazol-2-ylidene-N′-phenylurea ligand in the coordination sphere – syntheses and solid state structures

We report the syntheses and structural studies of two nickel(II) complexes of imidazol-2-ylidene- N′-phenylureate ligand of composition [{ImtBuNCON(H)Ph}2Ni(acac)2](1) and [(C6H5NH2)2Ni(acac)2][ImMes NCON(H)Ph] (2). The nickel complex 1 was readily prepared by the reaction of nickel(II) acetylacetonate [Ni(acac)2] with imidazol-2-ylidene-N′-phenylureate ligand [Im tBuNCON(H)Ph] (L1) in THF under reflux condition for 72 h. The nickel complex 2 was obtained by the reaction of [Ni(acac)2], mesityl derivative of imidazol-2-ylidene-N′-phenylureate ligand [Im MesNCON(H)Ph] (L2) in the presence of aniline as base under reflux condition in THF. Both the paramagnetic complexes have been characterized by FT-IR spectroscopy and elemental analyses. Solid-state structures of both the new complexes were established by single crystal X-ray diffraction analysis. In the molecular structures of complexes 1 and 2, each nickel(II) ion is six fold coordinated and form a distorted octahedral geometry. The optical properties of both complexes have been explored. The Hirshfeld surfaces are used to view and analyze the intermolecular contacts in crystalline state for complex 2. We report the synthesis and structures of two octahedral nickel(II) complexes supported by imidazol-2-ylidene-N′-phenylureate ligand.

Preparation and characterization of “clickable” polyaniline derivatives on graphene modified electrodes

The electrochemical polymerization of 2- and 3-ethynylaniline and copolymers with aniline was investigated. It is found that 3-ethynylaniline is more reactive than 2-ethynylaniline and, in the presence of aniline it electropolymerizes. The effect of the electrode material on the electropolymerization of 3-ethynylaniline and its copolymers with aniline was studied and graphene-modified electrodes show very good performance for the formation of a PANI-like polymer, as demonstrated by FTIR and Raman measurements. The graphene layer thickness also appears to influence the polymerization, the best results obtained for the thinnest films used. Finally, copolymers of aniline and 3-ethynylaniline were chemically prepared at room temperature. These copolymers display PANI-like structure with alkyne grafted groups and showed good electrochemical response, slightly different to that of the parent PANI with lower electrical conductivity. Preliminary tests indicate that the PANI derivative can be successfully clicked to poly(ethylene glycol) by a thiol-yne click reaction.

The one-pot synthesis of methylene diphenyl-4,4′-dicarbamate

Methylene diphenyl-4,4′-dicarbamate (MDC) is an intermediate for the preparation of methylene diphenyl diisocyanate. This paper reports the one-pot synthesis of MDC using aniline, dimethyl carbonate, and formalin as raw materials. Phenyl N-methyl carbamate (MPC) synthesis was carried out in a batch reactor using Zn(OAc)2 as the catalyst, following which, without any separation, an Hβ catalyst and formalin were added to continue to MPC condensation to give MDC. It was found that there were interactions between the MPC synthesis and MPC condensation, such that the presence of aniline could inhibits MPC condensation. Zn(OAc)2 was also found to adsorb on the Hβ surface to form Si–O–Zn bonds during the condensation, decreasing the quantity of strong acid sites on the Hβ and reducing the catalytic performance. Under the optimal conditions for the one-pot synthesis of MDC, aniline conversion was 100% and the MDC yield was 73.9% (based on HCHO). The deactivated catalyst could be easily regenerated by treatment with acetic acid. The filter cake was dried and calcined to obtain regenerated Hβ and the filtrate was dried by vacuum rotary evaporation to obtain Zn(OAc)2. No significant loss in catalytic activity was observed for the regenerated catalyst.

English

In this study, we have isolated four different species from effluent contaminated soil using a mixture of aniline and 4-chloroaniline (4CA) as principal carbon sources. The four species were identified as Pseudomonas stutzeri A, Comamonas testosterone B, Pseudomonas putida C and Stenotrophomonas maltophilia D. Growth studies on aniline and 4CA as single and mixed substrates demonstrated that the bacteria preferred to grow on and utilize aniline rather than 4CA. However, despite 100% disappearance of the parent substrates, the degradation of 4CA was always characterized by incomplete dechlorination and 4-chlorocatechol accumulation. HPLC-UV analysis showed that 4-chlorocatechol was further degraded via an ortho-cleavage pathway by the bacterial consortium. This hypothesis was supported by the results from enzyme assays of the crude cell extract of the consortium revealing catechol 1,2-dioxygenase activity which converted catechol and 4-chlorocatechol to cis,cis-muconic acid and 3-chloro-cis,cis-muconic acid, respectively. However, the enzyme had a much higher conversion rate for catechol than for 4-chlorocatechol, indicating preference for non-chlorinated substrates. Members of the bacterial consortium were also characterized individually. All isolates were able to assimilate aniline. P. putida C was able to grow on 4CA solely, while S. maltophilia D was able to grow on 4-chlorocatechol. These results suggest that the degradation of 4CA in the presence of aniline by the bacterial consortium was a result of interspecies interactions. Key words: Chloroaniline, Pseudomonas, Comamonas, HPLC, catechol.

One pot green synthesis of polyaniline coated gold nanorods and its applications

Morphology controlled high aspect ratio worm-like polyaniline (PANI) layer coated Au-nanostructures (Au/PANI) have been successively synthesized by in situ polymerisation techniques using aniline as a monomer with HAuCl4 as an oxidising agent in the absence and presence of citric acid (CA). Synthesized composites were characterized by HRTEM, FESEM, XRD, XPS, UV-vis and FTIR study. Spherical morphologies are seen in the absence of CA and Au nanoparticles are coated by a PANI thin layer with ∼30 nm thickness. In the presence of CA, as well as depending upon the CA to aniline molar ratio, morphology varies from irregular assembly to regular fiber to spherical-like nanostructures. The nanostructures show fibrous morphology with an average diameter of ∼100 nm and lengths of more than 5 μm when CA to aniline molar ratios are 1.0 and 0.2. When the ratios are 2.0 and 0.1, the nanostructure represents the granular-like morphology. Nanofiber formation takes place by the assembly of the CA capped tiny Au-nanorods in the presence of aniline during the polymerisation, and all Au-nanorods are finely coated by a PANI thin layer of ∼5 nm thickness. Importantly, fibrous Au/PANI nanostructures show superior catalytic activity compared to spherical/irregular Au/PANI nanostructures towards the reduction of toxic aromatic nitro compounds like 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), 2,4-dinitrophenol (2,4-DNP) and 2,4,6-trinitrophenol (2,4,6-TNP). This is because of the coating thickness of PANI over Au-nanoparticles in fibrous Au/PANI nanostructures as well as enhanced surface area.

An in-situ electropolymerization based sensor for measuring salt content in crude oil

Determining salt content is a vital procedure in the petroleum industry during the process of crude oil transportation, refining and production. Monitoring the salinity value using a fast and direct technique can substantially lower the cost of crude oil in its processing and its production stages. In the present work, a novel analytical method was developed to detect the amount of salt present in crude oil in a quick and reliable manner. The measurement is based on the rate of in-situ electropolymerization of a monomer such as aniline in association with the salt content in the crude oil. The salt dispersed in the hydrocarbon matrix is used as an electrolyte in the electrolytic system to induce an electropolymerization reaction upon the induction of voltages, in which the salt content is measured corresponding to the polymeric film formation on the working electrode surface. Acetonitrile and N-methylpyrrolidone (NMP) were used in the electrochemical cell as solvents, and cyclic voltammetry tests were performed for Arabian crude oil solutions in the presence of aniline. The method has shown an excellent detection response for very low concentrations of salt. Four Arabian crude oils with salt concentrations of 34.2, 28.5, 14.3 and 5.71mgL−1 have produced current intensity of 180.1, 172.6, 148.1 and 134.2µA at an applied current potential of 1.75V (vs. Ag/AgCl), respectively. A Calibration curve was obtained in the range of 5–35mgL−1, giving limits of detection and quantitation at 1.98 and 5.95mgL−1, respectively. The in-situ electropolymerization based sensor has significant advantages over the existing techniques of salt monitoring in crude oil such as fast response, temperature independency, electrode stability, and minimum sample preparation.