Molecular structure, spectroscopic (FT-IR, FT-Raman, NMR, UV) studies and first-order molecular hyperpolarizabilities of 1,2-bis(3-methoxy-4-hydroxybenzylidene)hydrazine by density functional method

Antimalarial potential, LC-MS secondary metabolite profiling and computational studies of Zingiber officinale

Malaria is among the top-ranked parasitic diseases that pose a threat to the existence of the human race. This study evaluated the antimalarial effect of the rhizome of Zingiber officinale in infected mice, performed secondary metabolite profiling and detailed computational antimalarial evaluation through molecular docking, molecular dynamics (MD) simulation and density functional theory methods. The antimalarial potential of Z. officinale was performed using the in vivo chemosuppressive model; secondary metabolite profiling was carried out using liquid chromatography-mass spectrometry (LC-MS). Molecular docking was performed with Autodock Vina while the MD simulation was performed with Schrodinger desmond suite for 100 ns and DFT calculations with B3LYP (6-31G) basis set. The extract showed 64% parasitaemia suppression, with a dose-dependent increase in activity up to 200 mg/kg. The chemical profiling of the extract tentatively identified eight phytochemicals. The molecular docking studies with plasmepsin II and Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) identified gingerenone A as the hit molecule, and MMGBSA values corroborate the binding energies obtained. The electronic parameters of gingerenone A revealed its significant antimalarial potential. The antimalarial activity elicited by the extract of Z. officinale and the bioactive chemical constituent supports its usage in ethnomedicine.Communicated by Ramaswamy H. Sarma.

β-Ketoallylic methylsulfones synthesis via inert C(sp3)-H bond activation by magnetic Ag-Cu MOF

Herein, the one-pot tandem synthesis of β-ketoallylic methylsulfones has been achieved from readily available dimethyl sulfoxide and acetophenones as coupling partners in one step. In this procedure, dimethyl sulfoxide serves as a triple role including solvent, dual synthon and as an oxidant agent. The use of magnetic Ag-Cu MOF as a bimetallic catalyst is the key to the progress of the reaction due to its accessible active sites. It provides facile access to various β-ketoallylic methylsulfone derivatives from direct C(sp3)-H bond activation and functionalization of aromatic methyl ketones especially acetophenones with electron-rich and electron-poor groups. Moreover, the present work offers a synthetically powerful strategy to form products in good to excellent yields (74-96%) with the atom, step, and pot economics. It has also delivered a new chromane-4-one derivative from 2-hydroxy acetophenone with intramolecular Michael-addition of related β-ketoallyl methylsulfone product. In the final step, the electronic properties of some products have been predicted with the theoretical studies.

A recent overview of surfactant-drug interactions and their importance

This review focuses on the self-aggregation properties of different drugs, as well as on their interaction with anionic, cationic, and gemini surfactants. The interaction of drugs with surfactants has been reviewed concerning conductivity, surface tension, viscosity, density, and UV-Vis spectrophotometric measurements, and their relation with critical micelle concentration (CMC), cloud point, and binding constant. The conductivity measurement technique is used for the micellization of ionic surfactants. Cloud point studies can be used for the non-ionic, and also for certain ionic surfactants. Usually, surface tension studies are mostly employed for non-ionic surfactants. The degree of dissociation that is determined is used to evaluate thermodynamic parameters of micellization at various temperatures. The effect of external parameters like temperature, salt, solvent, pH, etc., is discussed for thermodynamics parameters using recent experimental works on drug-surfactant interactions. Consequences of drug-surfactant interaction, condition of drugs during interaction with surfactants, and applications of drug-surfactant interaction are being generalized which reflects current and future potential uses of drug-surfactant interactions.

LC-MS Analysis, Computational Investigation, and Antimalarial Studies of Azadirachta indica Fruit

Malaria is a deadly disease that continues to pose a threat to children and maternal well-being. This study was designed to identify the chemical constituents in the ethanolic fruit extract of Azadirachta indica, elucidate the pharmacological potentials of identified phytochemicals through the density functional theory method and carry out the antimalarial activity of extract using chemosuppression and curative models. The liquid chromatography-mass spectrometry (LC-MS) analysis of the ethanolic extract was carried out, followed by the density functional theory studies of the identified phytochemicals using B3LYP and 6-31G (d, p) basis set. The antimalarial assays were performed using the chemosuppression (4 days) and curative models. The LC-MS fingerprint of the extract led to the identification of desacetylnimbinolide, nimbidiol, O-methylazadironolide, nimbidic acid, and desfurano-6α-hydroxyazadiradione. Also, the frontier molecular orbital properties, molecular electrostatic potential, and dipole moment studies revealed the identified phytochemicals as possible antimalarial agents. The ethanolic extract of A indica fruit gave 83% suppression at 800 mg/kg, while 84% parasitaemia clearance was obtained in the curative study. The study provided information about the phytochemicals and background pharmacological evidences of the antimalarial ethnomedicinal claim of A indica fruit. Thus, isolation and structure elucidation of the identified phytochemicals from the active ethanolic extract and extensive antimalarial studies towards the discovery of new therapeutic agents is recommended for further studies.

Vibrational Spectroscopy, Quantum Computational and Molecular Docking Studies on 2-[(1H-Benzimidazol-1-yl)-methyl]benzoic Acid

Experimental and theoretical investigations on the optimized geometrical structure, electronic and vibrational features of 2-[(1H-benzimidazol-1-yl)-methyl]benzoic acid are provided using the B3LYP/6-311++G(d,p) basis set. The Vibrational Energy Distribution Analysis (VEDA) program was used to perform the vibrational assignments and calculate the Potential Energy Distribution (PED). The acquired FT-IR and FT Raman data were used to complete the vibrational assignment and characterization of the compound fundamental modes. Theoretical and actual NMR chemical shifts were found to be quite similar. The UV-vis spectrum of 21HBMBA, as well as effects of solvents, have been investigated. The calculated HOMO and LUMO energies reveal that charge transfer happens within the molecule and MEP surface to be a chemically reactive area appropriate for drug action. Furthermore, a thorough examination of Non-Bonding Orbitals, excitation energies, AIM charges, Fukui functions and the Electron Localization Function (ELF) is carried out. The research is also expanded to compute first-order hyperpolarizability and forecast NLO characteristics. The details of the docking studies aided in the prediction of protein binding.

Elucidating the Glucokinase Activating Potentials of Naturally Occurring Prenylated Flavonoids: An Explicit Computational Approach

Glucokinase activators are considered as new therapeutic arsenals that bind to the allosteric activator sites of glucokinase enzymes, thereby maximizing its catalytic rate and increasing its affinity to glucose. This study was designed to identify potent glucokinase activators from prenylated flavonoids isolated from medicinal plants using molecular docking, molecular dynamics simulation, density functional theory, and ADMET analysis. Virtual screening was carried out on glucokinase enzymes using 221 naturally occurring prenylated flavonoids, followed by molecular dynamics simulation (100 ns), density functional theory (B3LYP model), and ADMET (admeSar 2 online server) studies. The result obtained from the virtual screening with the glucokinase revealed arcommunol B (−10.1 kcal/mol), kuwanon S (−9.6 kcal/mol), manuifolin H (−9.5 kcal/mol), and kuwanon F (−9.4 kcal/mol) as the top-ranked molecules. Additionally, the molecular dynamics simulation and MM/GBSA calculations showed that the hit molecules were stable at the active site of the glucokinase enzyme. Furthermore, the DFT and ADMET studies revealed the hit molecules as potential glucokinase activators and drug-like candidates. Our findings suggested further evaluation of the top-ranked prenylated flavonoids for their in vitro and in vivo glucokinase activating potentials.

Vibrational spectroscopy, quantum computational and molecular docking studies on 2-chloroquinoline-3-carboxaldehyde

The quantum mechanical density functional theory (DFT) approach was used to analyze vibrational spectroscopy for the title compound 2-chloroquinoline-3-carboxaldehyde, and the observations were compared to experimental results. B3LYP with the 6-311++ G (d, p) basis set produces the optimized molecular structure and vibrational assignments. The charge delocalization and hyper conjugative interactions were studied using NBO analysis. Fukui functions were used to determine the chemical reactivity of the examined molecule. The linear polarizability, first order polarizability, NLO and Thermodynamic properties are calculated. Additionally, Molecular electrostatic potential (MEP) and HOMO-LUMO are reported. Multi wavefunction analysis like ELF (Electron Localization Function) and LOL (Localized Orbital Locator) are analyzed. For the headline compound, drug-likeness properties were examined. Molecular docking analysis on the examined molecule are done to understand the biological functions of the headline molecule and the minimum binding energy, hydrogen bond interactions, are analyzed.

Molecular, Electronic, Nonlinear Optical and Spectroscopic Analysis of Heterocyclic 3-Substituted-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones: Experiment and DFT Calculations

In the present study, 3-p-methoxybenzyl/m-chlorobenzyl/phenyl-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones were obtained from the reaction between 3-methylthiophene-2-carbaldehyde and three different 4-amino-(3-p-methoxybenzyl/m-chlorobenzyl/phenyl)-4,5-dihydro-1H-1,2,4-triazole-5-ones. In order to compare experimental and theoretical values, the geometric parameter, electronic, nonlinear optical properties, molecular electrostatic potentials and spectroscopic properties of 3-substituted-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones have been simulated. The electronic properties of the newly synthesized compounds were calculated using DFT/B3LYP and DFT/B3PW91 methods revealing parameters such as ionization potential, electron affinity, energy gap, electronegativity, molecular hardness, molecular softness, electrophilic index, nucleophilic index and chemical potential, all obtained from HOMO and LUMO energies, dipole moments and total energies. UV-visible absorption spectra and the stimulation contributions in UV-visible transitions were obtained by using TD-DFT/B3LYP/6-311G(d,p) and TD-DFT/B3PW91/6-311G(d,p) methods in ethanol. The calculated absorption wavelengths, oscillator power and excitation energies were compared with experimental values. In line with DFT, the numbers of molecular vibration were analyzed through the basis set of 6-311G(d,p). The recording of FT-IR frequencies was done for the pertinent compound. The recorded frequencies through DFT/B3LYP and DFT/B3PW91 methods were compared to experimental values, with a result gained closest to the values of B3LYP. Finally, the Gaussian09W program package in DMSO phase, starting from the optimized structure, has been instrumental in calculating the 13C-NMR and 1H-NMR chemical shift values of the GIAO method.

Spectroscopic elucidation (FT-IR, FT-Raman and UV-visible) with NBO, NLO, ELF, LOL, drug likeness and molecular docking analysis on 1-(2-ethylsulfonylethyl)-2-methyl-5-nitro-imidazole: An antiprotozoal agent

1-(2-ethylsulfonylethyl)-2-methyl-5-nitro-imidazole (1EMI) C₈H₁₃N₃O₄S also known as Tinidazole, selected for its antiprotozoal property is extensively used for spectroscopic elucidations and computational aspects using density functional methods. Along with spectral conclusions, further investigations on fundamental reactive properties such as electrical, optical, nonlinear combined with DFT simulations were performed. Molecular docking procedure supports the results of chosen appropriate antiprotozoal agent based on ligand-protein interactions. Experimental and simulated (B3LYP/6-311++G (d,p)) IR and Raman spectra showed concurrence. NLO analysis through first order hyperpolarizability parameter helps in finding the potential of 1EMI as a good NLO candidate. Charge delocalization and the stability of the compound were discussed using natural bond orbital (NBO) analysis. Furthermore, Electron localization function (ELF), local orbital locator (LOL), and Frontier molecular orbitals (FMO) were studied. Besides, Mulliken population analysis on atomic charges, Energy gap, chemical potential, global hardness, softness, ionization potential, electronegativity, electrophilicity index along thermodynamic parameters (enthalpy, entropy and heat capacity) have been calculated. Drug likeness parameters and molecular docking approach enabled to check pharmaceutical potential and biological activity of 1EMI. The biological activity of 1EMI through ligand and protein interactions have been confirmed theoretically for the treatment of Malaria, Invasive aspergillosis and Mycobacterium tuberculosis with respect to chosen proteins. Three different activity targets and protein interactions are quite successful revealing the bond distances, intermolecular energy, binding energy and inhibition constant. 2D interaction profile image of the two maximum interacted proteins and also Ramachandran plot used to show stereochemistry of selected protein. The activities of 1EMI were studied in accordance with literature survey and the results were presented.

Crystal structures and Hirshfeld surface analyses of halogen substituted azine derivatives, 1,4-bis(halophenyl)-2,3-diazabuta-1,3-dienes

The crystal structures and Hirshfeld surface analyses are reported, from data collected at 100 K, of six 1,4-bis(X,Y-phenyl)-2,3-diazabuta-1,3-dienes (1–6), namely (1: X, Y=H, 4-Cl; 2: X, Y=3,4-Cl2; 3: X, Y=2,4-Cl2; 4: X, Y=H, 2-Br, H; 5: X, Y=H, 3-Br; 6: X, Y=H, 4-Br. The six halogen derivatives crystallise in the monoclinic group P21/c. In each case, the asymmetric unit is one half of the molecule, with the molecules lying across inversion centres, midway between the N–N bonds, with the central C–C=N–N=C–C fragments having all transoid conformations. Each of the six molecules deviates a little from overall planarity. The π···π stacking interactions are the most important intermolecular interactions in each of the six compounds. In the cases of 3 and 4, the π···π stacks are augmented by additional C–X···π (X=Cl or Br) interactions, while in 4, the π···π stacks are linked by weak Br···Br interactions, and in 3, weak Cl···Cl contacts are considered to be also involved in cementing the supra molecular arrangements. The short separations of the layers within the stacks and the extent of the overlaps of the π systems point to significant strengths of the π···π interactions. Comparisons with published structures of related chloro and fluoro compounds indicated similar results: related iodo derivatives, IC6H4CH=N–N=CHC6H4I do not possess as strong π···π interactions. The Hirshfeld analysis indicated further intermolecular contacts which fell outside the normal PLATON cutoff values.

Quantum mechanical, spectroscopic and docking studies of 2-Amino-3-bromo-5-nitropyridine by Density Functional Method

Experimental and theoretical investigations on the molecular structure, electronic and vibrational characteristics of 2-Amino-3-bromo-5-nitropyridine are presented. The vibrational frequencies were obtained by DFT/B3LYP calculations employing 6-311++G (d, p) basis set. This was compared with experimental FT-IR and FT-Raman spectral data. Simulated FT-IR (4000-400cm^-1) and FT-Raman spectra (4000-100cm^-1) showed good agreement with the observed spectra. The molecular equilibrium geometry of the title compound was fully optimized. Quantum chemical calculations of the equilibrium geometry and the complete vibrational assignments of wavenumbers using potential energy distribution (PED) were calculated with scaled quantum mechanics. HOMO-LUMO energies, energy gap (ΔE), electronegativity (χ), chemical potential (μ), global hardness (η), softness (S) and the Fukui function were calculated for the title molecule. The title compound has a low softness value (0.239) and the calculated value of electrophilicity index (5.905) describes the biological activity. The stability and charge delocalization of the title molecule were studied by Natural Bond Orbital (NBO) analysis, Non-Linear Optical (NLO) behaviour in terms of first order hyperpolarizability, dipole moment and anisotropy of polarizability and Molecular Electrostatic Potential (MEP) were accounted. The computed values of μ, α and β for the title molecule are 1.851 Debye, 1.723×10^-23esu and 7.428×10^-30esu respectively. The high β value and non-zero value of μ indicate that the title compound might be a good candidate for NLO material. Thermodynamic properties of the title molecule were studied for different temperatures thereby revealing the correlations between heat capacity (C), entropy (S) and enthalpy changes (H) with temperatures. Docking studies of the title compound were scrutinized to predict the preferred binding orientation, affinity and activity of the given compound. The title compound was docked into the active site of the protein 5FCT which belongs to the class of proteins exhibiting the property as a Dihydrofolate synthase inhibitor. A minimum binding energy of -5.9kcal/mol and intermolecular energy of -6.5kcal/mol is seen in the interaction.

The spectroscopic (FT-IR, FT-Raman, dispersive Raman and NMR) study of ethyl-6-chloronicotinate molecule by combined density functional theory

In this study, ethyl-6-chloronicotinate (E-6-ClN) molecule is recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1) (FT-IR, FT-Raman and dispersive Raman, respectively) in the solid phase. ((1))H and ((13))C nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The structural and spectroscopic data of the molecule are obtained for two possible isomers (S1 and S2) from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule is fully optimized, vibrational spectra are calculated and fundamental vibrations are assigned on the basis of the potential energy distribution (PED) of the vibrational modes. ((1))H and ((13))C NMR chemical shifts are calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strengths, wavelengths, HOMO and LUMO energies, are performed by time-dependent density functional theory (TD-DFT). Total and partial density of state and overlap population density of state diagrams analysis are presented for E-6-ClN molecule. Furthermore, frontier molecular orbitals (FMO), molecular electrostatic potential, and thermodynamic features are performed. In addition to these, reduced density gradient of the molecule is performed and discussed. As a conclusion, the calculated results are compared with the experimental spectra of the title compound. The results of the calculations are applied to simulate the vibrational spectra of the molecule, which show excellent agreement with the observed ones. The theoretical and tentative results will give us a detailed description of the structural and physicochemical properties of the molecule. Natural bond orbital analysis is done to have more information stability of the molecule arising from charge delocalization, and to reveal the information regarding charge transfer within the molecules.