A combined experimental (IR, Raman and UV-Vis) and quantum chemical study of canadine (original) (raw)
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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
The molecular structures, vibrational frequencies and corresponding vibrational assignments of xanthine and its methyl derivatives (caffeine and theobromine) have been calculated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-31G(d, p) basis set level. The calculations were utilized to the C S symmetries of the molecules. The obtained vibrational frequencies and optimised geometric parameters (bond lengths and bond angles) were seen to be well agreement with the experimental data. The used scale factors which have been obtained the ratio of the frequency values of the strongest peaks in the calculated and experimental spectra seem to cause the gained vibrations well corresponding to the experimental ones. Theoretical infrared intensities and Raman activities are also reported. analogues of xanthine prototropic tautomers is rather good approach to experimental study of the prototroic tautomeric equilibrium in nucleotide basis if relative energies of high-energy tautomers are not less than a few kcal/mol [10]. Some authors have described that in the preparation of xanthine and its methyl derivatives some care should be taken since sample handling may affect the water content of these samples which causes pseudopolymorphic transformations affecting their biavailability and stability .
A Theoretical Structure-Affinity Relationship Study of Some Cannabinoid Derivatives
Journal of the Chilean Chemical Society, 2008
A ZINDO/1 quantum-chemical structure-affinity relationship study with the KPG model is presented for the in vitro interaction of a group of classical, indolederived and aminoalkylindole-derived cannabinoids with CB 1 and CB 2 receptors. From this work the following conclusions are obtained. CB 1 and CB 2 CB 2 receptor affinities are regulated by different mechanisms involving orbital and charge control. Nevertheless CB 1 and CB 2 classical ligands share three common features: a hydrogen bond to a lysine (for CB 1) or serine (for CB 2), a fully aromatic ring and a branched carbon side chain. In the case of indole-derived and aminoalkylindolederived cannabinoids orientation and alignment rules have been defined as a basis for the comparison of noncongeneric molecules. In this way it was possible to associate the location of molecular fragments of these systems with known molecular systems such as classical cannabinoids. For aminoalkylindoles we have proposed the locus with which they bind to a second receptor site that is available to WIN-55212-2 but not to classical cannabinoids. On the basis of our results we propose a new molecule that should help to discriminate between the above two receptor sites.
Boldo (Peumus boldus Mol.), a Chilean tree traditionally employed in folk medicine and recognized as a herbal remedy in a number of pharmacopoeias, mainly for the treatment of liver ailment, has recently been the subject of increasing attention. Boldine, in particular, the major and most characteristic alka-loid constituent of this plant species, now emerges as its most interesting active principle from the pharmacological viewpoint. In the present work the structural and spectral characteristics of boldine have been studied by methods of infrared, Raman spectroscopy and quantum chemistry. Electrostatic potential surface, optimized geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by ab initio Hartree-Fock (HF) and density functional theory (DFT) employing B3LYP with complete relaxation in the potential energy surface using 6-311G(d,p) basis set. A complete vibrational assignment is provided for the observed Raman and infrared spectra of boldine molecule.
International Journal of Research and Analytical Reviews (IJRAR), 2018
The FT-IR and FT-Raman spectra of 4-Carboxylphenylboronic acid (4CPBA) have been recorded in the range 4000-400 cm-1 and 4000-100 cm-1 respectively. Also the UV spectra of 4CPBA have been recorded and analyzed. The molecular structures, fundamental vibrational frequencies and intensity of the vibrational bands are investigated and interpreted theoretically with the use of structure optimization and normal coordinate factor filed calculations based on density functional theory (DFT) with basis set 6-311++G(d,p). The hyper conjugative interaction energy E (2) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. The energy gap of the molecule was found using HOMO-LUMO calculations. In addition studies of 1 H & 13 C NMR chemical shift values of 4CPBA in the ground state for LANL2DZ/6-311++G(d,p) basis set were also calculated using Gauge independent atomic orbital (GIAO) method. The UV-Visible analysis of the 4CPBA with LANL2DZ/6-311++G(d,p) level of basis set. From the title molecule various ligand are using in the cervical cancer protein by docking. The 4CPBA has been screened to antimicrobial activity and found to exhibit antibacterial effects. From, these the geometric parameters, harmonic vibrational frequencies, IR intensities, Raman intensities and absorption wavelength was compared with the available experimental data of the molecule.
2018
Sanguinarine is an alkaloid studied in the treatment of cancer cell proliferation. Found in several plants with Argemone mexicana Linn, the plant is used in traditional medicine from several countries with Mexico and India in the natural treatment of wounds, conjunctivitis and as hallucinogen. Due to these studies of this alkaloid, a study was made on a molecular structure of the sanguinarine, through quantum chemistry, via computational methods such as molecular mechanics, PM3, Hartree-Fock, density functional theory and Moller-Plesset. The main site of molecular interaction was determined to be the hydrogen atoms. This has a strong antioxidant potential in its structure. It probably interacts with free radicals reducing their carcinogenic effect on cells. A study of the infrared spectrum complemented the paper.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties are investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR and FT-Raman spectra of the title compound have been recorded in the region 4000-400 cm-1 and 4000-100 cm-1 respectively. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water is recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule are obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers are scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments are performed on the basis of the normal coordinate analysis (NCA), experimental result and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule is analyzed by NBO analysis. The molecule orbital contributions are studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies are reported. The calculated HOMO and LUMO energies show that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated.
International Journal of Quantum Chemistry, 2008
A set of 30 cannabinoid metabolites has been investigated from a combination of electronic and chemometric methods. Density functional calculations have been carried out to obtain optimized geometries, energies, and selected molecular Correspondence to: Tproperties. These molecular descriptors take into account steric effects, electronic properties, and chemical reactivity. The use of statistical methods including principal component analysis (PCA), hierarchical cluster analysis (HCA) and nonhierarchical cluster analysis (K-means), nearest neighbor (KNN) and artificial neural networks (ANN) has enabled to classify the compounds into psychoactive, moderately psychoactive and psychoinactive groups in good agreement with experimental evidences.
International Journal of Quantum Chemistry, 2000
The present work has been carried out a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of cyanuric acid. The FT-IR (100-4000 cm-1) and FT-Raman spectra (400-4000 cm-1) of cyanuric acid were recorded. In DFT methods, Becke's three parameter exchange-functional (B3) combined with gradientcorrected correlation functional of Lee, Yang and Parr (LYP) by implementing the splitvalence polarized 6-31G(d,p) and 6-31++G(d,p) basis sets have been considered for the computation of the molecular structure optimization, vibrational frequencies, thermodynamic properties and energies of the optimized structures. The Density Functional Theory (DFT) result complements the experimental findings. The electronic properties, such as HOMO-LUMO energies and molecular electrostatic potential (MESP) are also performed. Mulliken population analysis on atomic charges is also calculated. The first order hyperpolarizability (β total) of this molecular system and related properties (β, µ and ∆α) are calculated using DFT/B3LYP/6-31G (d,p) and B3LYP/6-311++G(d,p) methods. The thermodynamic functions (heat capacity, entropy and enthalpy) from spectroscopic data by statistical methods were also obtained for the range of temperature 50-1000 K.
Journal of The Chinese Chemical Society, 2019
Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs and have multiple therapeutic uses. These drugs are predominantly used for the treatment of musculoskeletal diseases because of their analgesic, antipyretic, and antiplatelet activities. Oxicams constitute an interesting class of organic compounds and have been investigated in the search for new analgesic and anti-inflammatory drugs. In the present work, a theoretical investigation of the molecular structure and spectroscopic properties of a series of five oxicams in different solvents was performed using density functional theory (DFT) methods. The geometric optimizations of the oxicams were carried out using the M06 density functional and the CBSB7 basis set. The infrared data were all obtained at the same theoretical level. The UV-Vis absorption and NMR data of some oxicams were calculated using the DFT and CBSB3 basis sets. The analysis of structural parameters, particularly the bond length and spectroscopic data, indicated that interactions occurred between the hydrogen bond types for 4-meloxicam, isoxicam, and normeloxicam. Stereoelectronic interactions caused by the substitution of alkyl groups caused the bond lengths to elongate. Similarly, the substitution of heteroatoms, such as nitrogen, sulfur, or oxygen, increased the bond lengths and angular stresses.