Interaction between favipiravir and hydroxychloroquine and their combined drug assessment: in silico investigations.

Hydroxychloroquine (HCQ) and favipiravir (FPV) are known to be effective antivirals, and there are reports about their use to fight the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) despite that these are not conclusive. The use of combined drugs is common in drug discovery, and thus, we investigated HCQ and FPV as a combined drug. The density functional theory method was used for the optimization of geometries, spectroscopic analysis and calculation of reactivity parameters. The quantum theory of atoms in molecules was applied to explain the nature of the hydrogen bonds and confirm the higher stability of the combined drug. We also evaluated the absorption, distribution, metabolism and excretion (ADME) parameters to assess their drug actions jointly using SwissADME. The preliminary findings of our theoretical study are promising for further investigations of more potent and selective antiviral drugs. Supplementary Information: The online version contains supplementary material available at 10.1007/s11696-021-01946-8.

Interaction between escitalopram and ibuprofen or paracetamol: DFT and molecular docking on the drug-drug interactions.

A large number of drugs are introduced each year to treat different diseases. Most of the time, patients suffer from more than one health problem which makes it necessary to take multiple drugs. When drugs are combined, the problem of drug-drug interaction becomes relevant. In this work, we studied the drug-drug interaction between escitalopram and ibuprofen or paracetamol using density functional theory and quantum theory of atoms in molecules. The results suggest that following the interactions, the activity of drugs changes according to site of interaction. Most reactive and most stable interactions would be preferable for the purpose of use. The in silico drug-likeness studies show that escitalopram and paracetamol couple is more bioavailable than escitalopram and ibuprofen couple. Moreover, in order to gain additional insights into the mentioned drugs' interactions, the drugs were docked separately and jointly against the potential targets for antidepressants and NSAIDs, namely 6HIS and 2PXX. The molecular docking results showed a potential improvement of the effectiveness of the drugs after combining by forming hydrogen bonds, hydrophobic contacts and π…π stacking.Communicated by Ramaswamy H. Sarma.

Theoretical insights of the drug-drug interaction between favipiravir and ibuprofen: a DFT, QTAIM and drug-likeness investigation.

One of the approaches adopted, as the first treatment method, in previous pandemic viruses before the production of new vaccines or drugs, is to evaluate the effectiveness of existing drugs. Sometimes, it is known that the combination of drugs provides better treatment by increasing the activity of the drugs due to mutual interactions. In this work, we used quantum theory of atoms in molecules and density functional theory to examine the structure and activity relationship between Favipiravir (FPV), a potential antiviral drug for ribonucleic acid viruses, and an inhibitor of influenza virus, and Ibuprofen (IBP), a nonsteroidal anti-inflammatory drug. The drug-likeness evaluations of IBP…FPV were also performed. It was observed that FPV and IBP interact in several ways via hydrogen bonding (HB) leading to changes in the activities of the combined drug and IBP…FPV is predicted to be orally bioavailable. It was also found that the highest occupied molecular orbital (HOMO) is located on IBP and the lowest unoccupied molecular orbital (LUMO) is distributed over FPV. The biological activity of the combined drug system is increased because of the small HOMO-LUMO energy gap value, partially covalent and non-covalent HB interactions.Communicated by Ramaswamy H. Sarma.

Can the Antivirals Remdesivir and Favipiravir Work Better Jointly? In Silico Insights.

The proverb "Old is gold" is applicable in drug discovery and the proverb "All that Glitters is not Gold" is also appropriate. In the COVID-19 era, there has been a race for drugs to be effective against SARS-CoV-2. There are reports about the uses of Remdesivir and Favipiravir as existing antivirals against virus but none have been conclusive so far. In the attempts for innovations, the combination of drugs is also under trials. Therefore, we used the density functional theory method and quantum theory of atoms in molecules to investigate drug-drug interactions involving Remdesivir and Favipiravir. The computed parameters were related to the antiviral actions of both drugs together. The results indicate enhanced antiviral activity and it will be worthy to consider additional investigations with the combination of these two drugs.

Complete experimental and theoretical proton and carbon nuclear magnetic resonance spectral assignments, molecular structure and conformational study of 1-cyclohexylpiperazine and 1-(4-pyridyl)piperazine.

The possible stable forms and molecular structures of 1-cyclohexylpiperazine (1-chpp) and 1-(4-pyridyl)piperazine (1-4pypp) molecules have been studied experimentally and theoretically using nuclear magnetic resonance(NMR) spectroscopy. (13)C, (15)N cross-polarization magic-angle spinning NMR and liquid phase (1)H, (13)C, DEPT, COSY, HETCOR and INADEQUATE NMR spectra of 1-chpp (C(10)H(20)N(2)) and 1-4pypp (C(9)H(13)N(2)) have been reported. Solvent effects on nuclear magnetic shielding tensors have been investigated using CDCl(3), CD(3) OD, dimethylsulfoxide (DMSO)-d(6), (CD(3))(2)CO, D(2)O and CD(2)Cl(2). (1)H and (13)C NMR chemical shifts have been calculated for the most stable two conformers, equatorial-equatorial (e-e) and axial-equatorial (a-e) forms of 1-chpp and 1-4pypp using B3LYP/6-311++G(d,p)//6-31G(d) level of theory. Results from experimental and theoretical data showed that the molecular geometry and the mole fractions of stable conformers of both molecules are solvent dependent.

(1)H, (13)C, (15)N NMR and (n)J(C, H) coupling constants investigation of 3-piperidino-propylamine: a combined experimental and theoretical study.

Proton coupled and decoupled (13)C, (1)H, (15)N, DEPT, COSY, HETCOR and INADEQUATE NMR spectra of 3-piperidino-propylamine (3-pipa) have been reported for the first time. In order to provide a precise structural elucidation, the magnitude of (n)J(C, H) (n=1, 2, 3) coupling constants of 3-pipa (C(8)H(18)N(2)) have been determined. Solvent effects on chemical shifts have been investigated by using CDCl(3) and DMSO. Molecular mobility of the title molecule has also been investigated by performing (13)C NMR spin-lattice relaxation time (T(1)) measurements. (13)C, (1)H and (15)N NMR chemical shifts and (1-3)J(C, H) coupling constants of 3-pipa have been calculated by means of B3LYP density functional method with 6-311++G(d,p) basis set. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting NMR properties.

Experimental and theoretical NMR study of 4-(3-cyclohexen-1-yl)pyridine.

(1)H, (13)C, DEPT, COSY, NOESY and HETCOR NMR spectra of 4-(3-cyclohexen-1-yl)pyridine (4-Chpy) have been reported for the first time. (1)H and (13)C NMR chemical shifts of 4-Chpy (C(11)H(13)N) have been calculated by means of the Hartree-Fock (HF) and Becke-3-Lee-Yang-Parr (B3LYP) density functional methods with 6-311++G(d,p) basis set. Comparison between the experimental and the theoretical results indicate that density functional B3LYP method is superior to the scaled HF approach for predicting NMR properties.

FT-IR spectroscopic investigation of some Hofmann type complexes: M(1-phenylpiperazine)2Ni(CN)4 (M=Ni, Co, Cd, Pd or Mn).

New Hofmann type complexes in the form of M(pp)(2)Ni(CN)(4) (where pp=1-phenylpiperazine and M=Ni, Co, Cd, Pd or Mn) have been prepared in powder form and their infrared spectra have been reported in the range of (4000-400) cm(-1). The thermal behaviours of these complexes have been investigated by differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA). Ni(pp)(2)Ni(CN)(4) complex has been examined via transmission electron microscope (TEM). The results suggest that these compounds are similar in structure to Hofmann type complexes and their structures consist of polymeric layers |M-Ni(CN)(4)|(infinity) with the pp molecule bounded to the metal atom (M).

FT-IR and NMR investigation of 1-phenylpiperazine: a combined experimental and theoretical study.

FT-IR and (1)H, (13)C, DEPT, COSY, NOESY, HETCOR, INADEQUATE NMR spectra of 1-phenylpiperazine (pp) have been reported for the first time except for its (1)H NMR spectrum. The vibrational frequencies and (1)H, (13)C NMR chemical shifts of pp (C(10)H(14)N(2)) have been calculated by means of the Hartree-Fock (HF) and Becke-Lee-Yang-Parr (BLYP) or Becke-3-Lee-Yang-Parr (B3LYP) density functional methods with 6-31G(d) and 6-31G(d,p) basis sets, respectively. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is superior to the scaled HF and BLYP approach for predicting vibrational frequencies and NMR properties.

4-Mercaptophenylboronic acid: conformation, FT-IR, Raman, OH stretching and theoretical studies.

4-Mercaptophenylboronic acid (4-mpba, C6H7BO2S) was investigated experimentally by vibrational spectroscopy. The molecular structure and spectroscopic parameters were studied by computational methods. The molecular dimer was investigated for intermolecular hydrogen bonding. Potential energy distribution analysis of normal modes was performed to identify characteristic frequencies. The present work provides a simple physical picture of the OH stretch vibrational spectra of 4-mpba and analogues of the compound studied. When the different computational methods are compared, there is a strong evidence of the better performance of the BLYP functional than the popular B3LYP functional to describe hydrogen bonding in the dimer. The findings of this research work should be useful to experimentalists in their quests for functionalised 4-mpba derivatives.

Vibrational spectroscopic investigation of 1-pyrrolidino-1-cyclohexene: a comparative density functional study.

Infrared and Raman spectra of 1-pyrrolidino-1-cyclohexene (1pych) have experimentally been reported in the region of 4000-100 cm(-1). The conformational analysis, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 1pych (C10H17N) have theoretically been examined by means of the Becke-3-Lee-Yang-Parr (B3-LYP) density functional theory (DFT) method together with the 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments have been made the basis of potential energy distribution (PED) and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1pych have been predicted. Angular distribution of the probability density of populations of its conformational isomers is determined by analysis of the potential energy surface (PES). Comparison between the experimental and theoretical results indicates that B3-LYP method is provides satisfactory results for the prediction vibrational wavenumbers and structural parameters and the mixture of envelope and twist conformers is supposed to be the most stable form of 1pych.

DFT, FT-IR and Raman investigations of 1-pyrrolidino-1-cyclopentene.

FT-IR and Raman spectra of 1-pyrrolidino-1-cyclopentene (1py1cp) were experimentally reported in the region of 4000-10 cm(-1) and 4000-100 cm(-1), respectively. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 1py1cp (C9H15N) were theoretically examined by means of the B3LYP hybrid density functional theory (DFT) method together with the 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments were made on the basis of the potential energy distribution (PED) and the thermodynamics functions, the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) of 1py1cp were predicted. Calculations were carried out employed for three different conformations of 1py1cp in gas phase. Comparison between the experimental and theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers and envelope conformer is predicted to be the most stable conformer of 1py1cp.

The investigation of the effect of thermal treatment on bentonites from Turkey with Fourier transform infrared and solid state nuclear magnetic resonance spectroscopic methods.

There is a great deal of interest in the building industry in burned clays for production of building materials. Therefore, the effect of heat treatment on natural bentonite from Turkey was investigated by Fourier transform infrared (FT-IR) between the region of 4000-400cm(-1) and (29)Si, (27)Al magic angle spinning nuclear magnetic resonance (MAS NMR) measurement techniques at various temperatures between 200 and 700°C for 2h. The structural changes were also investigated upon heat treatment.

FT-IR and Raman spectroscopic and quantum chemical investigations of some metal halide complexes of 1-phenylpiperazine.

New metal halide complexes in the form of M(pp)(2)Cl(2) (where pp=1-phenylpiperazine and M=Pd or Hg) have been prepared for the first time and their FT-IR and FT-Raman spectra are reported in the region of 4000-10 cm(-1) and 4000-50 cm(-1), respectively. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compounds are theoretically examined by means of B3LYP hybrid density functional theory (DFT) method together with Lanl2dz basis set. Furthermore, reliable vibrational assignments made on the basis of potential energy distribution (PED) were calculated and the thermodynamics functions, the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) of these compounds have been predicted. According to the results, theoretical values have been successfully compared against experimental data.

Vibrational spectroscopic study on some Hofmann-Td type clathrates: Ni(4-phenylpyridine)2M(CN)4·2G (M=Cd or Hg, G=1,4-dioxane).

New Hofmann-T(d) type clathrates in the form of Ni(4-Phpy)(2)M(CN)(4)·2G (where 4-Phpy=4-phenylpyridine, M=Cd or Hg and G=1,4-dioxane) have been prepared in powder form and their FT-IR and Raman spectra have been reported. The results suggest that these compounds are similar in structure to the Hofmann-T(d) type clathrates.