Azomethine Derivatives Research Articles

Colorimetric probe and optical behaviours of new azomethine derivatives of sulfonamide

Syntheses, colorimetric anion probe properties, density functional theory (DFT) studies, and optical properties of the Schiff bases; 4-fluoro-N-(2-hydroxy-5-methylbenzylidene) benzenesulfonamide (1), 4-fluoro-N-(2-hydroxy-5-nitrobenzylidene)benzenesulfonamide (2) and 4-fluoro-N-[(2-hydroxynaphthalen-1-yl)methylene]benzenesulfonamide (3) were reported. The structure of the compounds was elucidated using MS, FTIR, and UV-visible spectroscopic techniques. Their structures were examined by theoretical calculations using density functional theory (DFT). The colorimetric response of the Schiff base receptors in DMSO was investigated before and after the addition of an equivalent amount of each anion to evaluate the anion recognition properties. The ultrafast transient absorption spectroscopy measurements were performed to investigate the energy transfer dynamics and decay kinetics of the compounds 1-3. The fluorescence and wavelength-dependent pump-probe measurements of the compounds showed that the excited state lifetime of compound 2 is shorter than compounds 1 and 3. The fluorescence properties of compounds 1-3 were compatible with the pump-probe spectroscopy measurements. The compounds with longer ESA lifetimes showed higher fluorescence.

Синтез и прогноз противовоспалительной активности 2-замещенных 5,6,7,8-тетрагидробензо[4,5]тиено[2,3-d]пиримидин-4(3h)-она

The article presents a modified method for the synthesis of 2-substituted 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine-4(3H)-one and the predict of their anti-inflammatory activity. The proposed method for obtaining tetrahydrothienopyrimidine derivatives is preparatively effective and simple. Their synthesis was carried out by heterocyclization of azomethine derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide in the medium of glacial acetic acid with the catalytic addition of dimethyl sulfoxide. Preliminary prognosis of anti-inflammatory activity in silico method allowed us to identify the most promising compounds. Of these, the 4b structure containing a 2-hydroxyphenyl fragment in the second position of pyrimidine-4(3H)-one may be of the greatest interest. It seems appropriate to further study the spectrum of biological activity of the studied compounds.

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System.

A homologous set of liquid crystalline materials (Tn) bearing Schiff base/ester linkages were prepared and investigated via experimental and theoretical techniques. Terminal flexible groups of different chain lengths were connected to the end of phenylbenzoate unit while the other end of molecules was attached to the heterocyclic pyridine moiety. The molecular structures of the designed molecules were evaluated by FT-IR, NMR spectroscopic analyses, whereas their mesomorphic properties were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). They all exhibited dimorphic properties with the exception of the members having the shortest and longest terminal flexible chains (n = 6 and 16), which were monomorphic. The T16 derivative was further found possessing purely smectic A (SmA) mesophase while others have their lengths covered by nematic (N) phase. Moreover, the computational evaluation of the azomethine derivatives was carried out using a DFT approach. The polarity of the investigated derivatives was predicted to be appreciably sensitive to the size of the system. Furthermore, the Frontier molecular orbitals analysis revealed various distributions of electron clouds at HOMO and LUMO levels.

Targeted Synthesis and Analysis of Biologically Active Azomethine Derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide

Introduction. Azomethine derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide are acyclic precursors of biologically active compounds derived from 5,6,7,8-tetrahydro-3H-benzoteopheno[2,3-d]pyrimidine-4-one. Examples of these groups of compounds with different pharmacological properties are given in the literature, but their cytostatic effect is mainly described. These data and the preparative availability allow us to judge the prospects for further study and molecular design in a number of azomethine derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide. Optimization of methods for the synthesis and analysis of substances of this series and the identification of structure-activity relationship are of considerable interest for medical chemistry and pharmaceutical science. The resulting leading compounds will allow us to further develop laboratory requirements for the synthesis of an active pharmaceutical substance.Aim. To make a predict, optimize the synthesis conditions and develop a method for high performance liquid chromatography (HPLC) analysis of pharmacologically active azomethine derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide.Materials and methods. The prediction of biological activity was carried out through the web resource PASS Online. The synthesis of the target azomethines was carried out by the interaction of aromatic aldehydes with 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide in an ethanol. The reaction was monitored by thin-layer chromatography (TLC). The determination of related impurities was done by HPLC. The analysis was carried out under the conditions of isocratic elution with a mobile phase of acetonitrile – water (70:30).Results and discussion. The results of the prediction of the biological activity of the constructed structures suggest the manifestation of cytostatic, antitubercular and anti-inflammatory activity characteristic of all target azomethines. The analysis of the reactivity revealed the influence of substituents of aldehydes contained in the aromatic core on the completeness of the condensation reaction. The spectral characteristics clearly confirmed the structure of the products, and the HPLC results showed the purity of the obtained substances, which is more than 95 %.Conclusion. As a result of the conducted studies, the structure of promising azomethine derivatives of 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide was justified and the method of their synthesis and analysis by HPLC was optimized. In the future, the results of the research will allow us to identify the leading compounds with the specified pharmacological properties.

New Nitro-Laterally Substituted Azomethine Derivatives; Synthesis, Mesomorphic and Computational Characterizations.

Two new homologues series, based on two rings of the azomethine central group bearing the terminal alkoxy group of various chain lengths, were prepared. The alkoxy chain length varied between 6 and 16 carbons. The other terminal wing in the first series was the F atom, and the compound is named N-4-florobenzylidene-4-(alkoxy)benzenamine (In). The second group of compounds included a lateral NO2 substituent in addition to the terminal F atom, named N-(4-fluoro-3-nitrobenzylidene)-4-(alkyloxy)aniline (IIn). Mesomorphic and optical properties were carried out via differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Elemental analyses, FT-IR, and NMR spectroscopy were carried out to elucidate the molecular structures of the synthesized groups. Mesomorphic investigations indicated that all the synthesized homologues (In) were monomorphic, possessing the smectic A (SmA) phase monotropically, while the second group (IIn) members were non-mesomorphic. The experimental data indicated that the formation of the mesophase is affected by the protrusion of the lateral nitro group. The disruption of the mesophase in the second group was attributed to the increase of its molecular width, which affects its lateral intermolecular interactions. The computational simulations were in agreement with the experimental data. On the other hand, the location of NO2 group within the molecular geometry increased the melting temperature of the molecule, and thus, affected their thermal and physical properties. By discussing the estimated parameters, it was found that the molecular architecture, the dipole moment, and the polarizability of the investigated compounds are highly affected by the electronic nature and position of the terminal and lateral substituents as well as their volumes.

Antitumor and Antioxidant Activities of the New Synthesized Azomethine Derivatives: Experimental and Theoretical Investigations

In this study, the antioxidant property of eight new azomethine derivatives underwent theoretical and experimental investigations. Azomethines have antioxidant activity. This is the first time the molecular structures and antioxidant property of these derivatives have been studied. The molecular structures were optimized using Density functional theory (DFT). The Bond Dissociation Enthalpy (BDE), Mulliken Charges, NBO analysis, Ionization Potential (IP), Electron Affinities (EA), HOMO and LUMO energies, Hardness (η), Softness (S), Electronegativity (μ), Electrophilic Index (ω), Electron Donating Power (ω<sup>-</sup>), Electron Accepting Power (ω<sup>+</sup>), and Energy Gap (E<sub>g</sub>) were calculated in order to deduce scavenging action of the eight new synthesized azomethines (DIA-3,4,5,6,7,8,9,10). Spin density calculations and NBO analysis were also carried out to understand the antioxidant activity mechanism. These molecules have high antioxidant potential due to the planarity and formation of intramolecular hydrogen bonds. Experimental investigations establish high antioxidant and antitumor activities of the synthesized azomethine derivatives.

C(sp2) – H functionalization of aldimines and related compounds: advances and prospects

This is the first systematic review of the most relevant approaches to direct C(sp2)–H bond functionalization of azomethine derivatives. The scope of the applicability of various transformations is analyzed. The review assesses prospects of the application of this functionalization strategy in the multistep synthesis of valuable compounds for use in medicinal chemistry, materials science and related areas.The bibliography includes 124 references.

Molecular structure, spectral (FT-IR, FT-Raman, Uv-Vis, and fluorescent) properties and quantum chemical analyses of azomethine derivative of 4-aminoantipyrine

A detail of the theoretical study on the molecular geometry and the infrared vibrational frequency assignments of (E)-4-(2-methoxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (MBA-dMPP), a bioactive azomethine analog of antipyrine, have been reported and compared with the experimental results. The ground state optimized structure, torsional energies, vibrational wavenumbers, atomic charge analysis, molecular electrostatic potential (MEP) distributions, and energies and maps of frontier molecular orbitals (FMOs) of MBA-dMPP was analyzed using Density Functional Theory (DFT)-B3LYP/6-311G method. Potential energy surface (PES) scans showed that the ground state optimized geometry of MBA-dMPP possesses less torsional energy than that of the crystal structure. Mulliken atomic charge and MEP analyses were carried out to locate the donor-acceptor atoms and reactive sites in the molecule. Calculated quantum chemical descriptors and HOMO-LUMO energies described the molecular properties and reactivity of the studied molecule. We have also calculated average local ionization energy (ALIE) surfaces and Fukui functions to obtain the initial information for the nucleophilic and electrophilic reaction sites of the molecule. Time Dependent (TD)-DFT method was used to calculate electronic transition energy, wavelength, and oscillator strength of MBA-dMPP and to be compared with experimental UV-Vis spectra. The charge transfer mechanism within the molecule is also studied using TD-DFT/B3LYP-/6-311G approach. The fluorescence spectra of MBA-dMPP showed good Stokes shift properties.

Design, Synthesis, SAR Study, Antimicrobial and Anticancer Evaluation of Novel 2-Mercaptobenzimidazole Azomethine Derivatives.

Various analogues of benzimidazole are found to be biologically and therapeutically potent against several ailments. Benzimidazole when attached with heterocyclic rings has shown wide range of potential activities. So, from the above provided facts, we altered benzimidazole derivatives so that more potent antagonists could be developed. In the search for a new category of antimicrobial and anticancer agents, novel azomethine of 2-mercaptobenzimidazole derived from 3-(2- (1H-benzo[d]imidazol-2-ylthio)acetamido)benzohydrazide were synthesized. The synthesized analogues were characterized by FT-IR, 1H/13C-NMR and MS studies as well C, H, N analysis. All synthesized compounds were evaluated for in vitro antibacterial activity against Gram-positive (B. subtilis), Gram-negative (E. coli, P. aeruginosa, K. pneumoniae and S. typhi) strains and in vitro antifungal activity against C. albicans and A. niger strains by serial dilution method, the minimum inhibitory concentration (MIC) described in μM/ml. The in vitro anticancer activity of synthesized compounds was determined against human colorectal carcinoma cell line (HCT- 116) using 5-fluorouracil as standard drug. In general, most of the synthesized derivatives exhibited significant antimicrobial and anticancer activities. Compounds 8, 10, 15, 16, 17, 20 and 22 showed significant antimicrobial activity towards tested bacterial and fungal strains and compound 26 exhibited significant anticancer activity.

Optimization, Spectroscopic (Excited States, UV/Vis, Polarization) Studies, FMO, ELF, LOL, QTAIM, NBO Analysis and Electronic Properties of Two New Azomethine Derivatives: A Theoretical and Experimental Investigations

In the current study, the molecular structures of the two new azomethine dyes such as AAFOH-1 and AAFOH-2 have been investigated with the use of density functional theory (DFT/B3LYP/6-311+G(d)) in a DMSO solvent for the first time. The electronic spectra of the new dyes in a DMSO solvent were carried out by temporally dependent density functional theory (TD-DFT) method. The computed absorption spectral data of the investigated molecules are in good agreement with the experimental data, thus allowing an assignment of the UV/Vis spectra. The equilibrium geometry, the HOMO and LUMO molecular orbitals, excitation energies, oscillator strengths and natural bond orbital (NBO) analysis for the molecules have also been calculated and presented. The electron location function (ELF), localized orbital locator (LOL), and quantum theory of atoms in molecules (QTAIM) analyses were also carried out. On the basis of polyvinyl alcohol (PVA) and the new synthesized azomethine dyes polarizing films were developed. The main optical parameters of polarizing PVA-films (transmittance, polarization efficiency, and dichroic ratio) have been measured and discussed. Anizotropy of thermal conductivity of the PVA-films have been studied.

Synthesis and Evaluation of Anticonvulsant Activity of Some Schiff Bases of 7-Amino-1,3-dihydro-2H-1,4-benzodiazepin-2-one.

A variety of 1,3-dihydro-2H-1,4-benzodiazepin-2-one azomethines and 1,3-dihydro-2H-1,4-benzodiazepin-2-one benzamide were prepared, characterized and evaluated for the anticonvulsant activity in the rat using picrotoxin-induced seizure model. The prepared 1,3-dihydro-2H-1,4-benzodiazepin-2-one azomethine derivatives emerged potentially anticonvulsant molecular scaffolds exemplified by compounds, 7-{(E)-[(4-nitrophenyl)methylidene]amino}-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, 7-[(E)-{[4-(dimethylamino)phenyl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, 7-{(E)-[(4-bromo-2,6-difluorophenyl)methylidene]amino}-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one and 7-[(E)-{[3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one. All these four compounds have shown substantial decrease in the wet dog shake numbers and grade of convulsions with respect to the standard drug diazepam. The most active compound, 7-[(E)-{[4-(dimethylamino)phenyl]methylidene}amino]-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one, exhibited 74 % protection against convulsion which was higher than the standard drug diazepam. Furthermore, to identify the binding mode of the interaction amongst the target analogs and binding site of the benzodiazepine receptor, molecular docking study and molecular dynamic simulation were carried out. Additionally, in silico pharmacokinetic and toxicity predictions of target compounds were carried out using AdmetSAR tool. Results of ADMET studies suggest that the pharmacokinetic parameters of all the target compounds were within the acceptable range to become a potential drug candidate as antiepileptic agents.

Quantum chemical modeling, synthesis, FT-IR, 1H NMR, 13C NMR and UV/Vis of new azomethine derivatives

In this study, the two new azomethine derivatives:have been investigated by using density functional theory (DFT: B3LYP/LanL2DZ and B3LYP/MidiX) in solvent water for the first time. After quantum-chemical calculations, two new azomethine derivatives were synthesized. The HOMO and LUMO orbitals, MEP, excitation energies, natural charges, oscillator strengths for the molecules have also been calculated. NBO analysis has been calculated in order to elucidate the intramolecular, rehybridization and delocalization of electron density and investigation. The electronic spectra of the new derivatives in solvent water were performed by the time-dependent DFT (TD-DFT) method. FT-IR, NMR and UV/Vis absorption spectra of the complexes were measured and discussed.

Azomethine derivatives of p-aminobenzoic acid as antioxidants and xanthine oxidase inhibitors

Azomethine derivatives of p-aminobenzoic acid as antioxidants and xanthine oxidase inhibitors

Dinuclear cobalt and iron complexes with azomethine derivative of 1,10-phenanthroline: quantum chemical study

Geometry, energy and magnetic characteristics of binuclear compounds of 5,6-bis(salicylideneimino)-1,10-phenanthroline with cobalt and iron have been computationally studied by means of density functional theory method (DFT UTPSSh/6-311++G(d, p)). Complexes comprising two magnetically active fragments capable of manifesting spin-crossover and valence tautomerism have been constructed via completion of the coordination sphere of the metal ions with ancillary ligands. These effects provide for variation of spin states in a wide range, which endows the studied compounds properties of molecular switches and spin qubits.

Dinuclear Cobalt and Iron Complexes with an Azomethine Derivative of 1,10-Phenanthroline: A Quantum-Chemical Study

Dinuclear Cobalt and Iron Complexes with an Azomethine Derivative of 1,10-Phenanthroline: A Quantum-Chemical Study

Spectroscopic (FT-IR, excited states, UV/Vis, polarization) properties, synthesis and quantum chemical studies of new azomethine derivatives

In the given research, the molecular structures of the four new azomethine compounds:have been studied with the use of density functional theory (DFT/RPBE1PBE/MidiX) in dimethylformamide (DMF) for the first time. The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory (TD-DFT) method. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV/Vis spectra. The equilibrium geometry, the HOMO and LUMO molecular orbitals, excitation energies, oscillator strengths for the molecules have also been calculated and presented. FT-IR spectra of the title molecules are recorded and discussed. On the basis of polyvinyl alcohol (PVA) and synthesized molecules polarizer for UV/Vis region of the spectrum has been developed.

Synthesis and Investigation of Copper Complexes with Selected Azomethine Monobenzo Crown Ether Derivatives

A series of novel azomethine derivatives of benzo-18-crown-6, benzo-15-crown-5, and aniline as well as their complexes with copper(II) acetate have been synthesized. Using the MTT assay, the antitumor activity of the obtained compounds has been determined. The effect of individual structural elements on the antitumor activity of the whole compound has been assessed.

Ligand based design and synthesis of pyrazole based derivatives as selective COX-2 inhibitors

The design and synthesis of novel pyrazole based derivatives has been carried out using the ligand based approach like pharmacophore and QSAR modelling of reported pyrazoles from the available literature to investigate the chemical features that are essential for the design of selective and potent COX-2 inhibitors. Both pharmacophore and QSAR models with good statistical parameters were selected for the design of the lead molecule. Also by exploiting the chemical structures of selective and marketed COX-2 inhibitors, celecoxib and SC-558 were used in designing the molecules which are used in the treatment of inflammation and related disorders. The therapeutic action of the Non-Steroidal Anti-inflammatory Agents (NSAIDs) is based primarily on the COX-2 inhibition. With this background we have synthesized some azomethine derivatives of 3-methyl-1-substituted-4-phenyl-6-[{(1E)-phenylmethylene}amino]-1,4-dihydro pyrano[2,3-c]pyrazole-5-carbonitrile 6(a-o) and were characterized by 1HNMR, 13CNMR and Mass spectral techniques. All the synthesized pyrazole derivatives were tested for in vitro membrane stability property in both COX-1 & COX-2 inhibition studies and in vivo anti-inflammatory activity by carrageenan induced rat paw edema model. Among them, compound 6k showed very good activity by in vivo anti-inflammatory activity with 0.8575 mmol/kg as ED50. Similarly compounds 6m, 6o, 6i and 6h exhibited comparable anti-inflammatory activity to standard drugs. Also the active compounds were further screened for ulcerogenic activity and were found be safer with less ulcer index compared to the marketed drugs like aspirin, ibuprofen and celecoxib.

Sonochemical synthesis, characterization, biological applications, and DFT study of new nano-sized manganese complex of azomethine derivative of diaminomaleonitrile

The characterization of a new, synthesized Mn(II) Schiff base complex of the [MnL2Cl]Cl type (where L = 2-((pyridine-4-yl)metheleneamino)-3-aminomaleonitrile) was carried out by FT-IR, UV–Vis, DRS, GC–Mass, photoluminescence spectroscopy (PL) and elemental analysis. The production of Mn3O4 nanoparticles using thermal decomposition and its spectral properties in the current study is being checked. The nano compounds were characterized by X-ray diffraction, scanning electron microscopy (SEM), and the X-ray energy-dispersive spectrometry analyses. Synthesized manganese oxide nanoparticles have a tetragonal structure with the average size of 25–150 nm. The results of SEM showed that the morphology of [MnL2Cl]Cl was rod-like while the morphology of the Mn3O4 was rod-like as well as spherical. Also, the metal complexes’ antibacterial and antifungal activities were evaluated. The results of the microbiology activities indicated that the metal compounds exhibited stronger microbiology efficiencies than the ligand did.

Inhibitor effect of new azomethine derivative containing an 8-hydroxyquinoline moiety on corrosion behavior of mild carbon steel in acidic media

Inhibitor effect of new azomethine derivative containing an 8-hydroxyquinoline moiety on corrosion behavior of mild carbon steel in acidic media