Thiol-thione tautomeric analysis, spectroscopic (FT-IR, Laser-Raman, NMR and UV-vis) properties and DFT computations of 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule

Secosteroid thiosemicarbazides and secosteroid-1,2,4-triazoles as antiproliferative agents targeting breast cancer cells: Synthesis and biological evaluation

A convenient and selective approach to 13,17-secoestra-1,3,5(10)-trien-17-oic acid [N'-arylcarbothioamido]hydrazides and hybrid molecules containing secosteroid and 1,2,4-triazole fragments was disclosed and these novel types of secosteroids were screened for cytotoxicity against hormone-dependent human breast cancer cell line MCF-7. Most of secosteroid-1,2,4-triazole hybrids showed significant cytotoxic effect comparable or superior to that of the reference drug cisplatin. Hit secosteroid-1,2,4-triazole hybrids 4b and 4h were characterized by high cytotoxicity and good selectivity towards MCF-7 breast cancer cells. PARP cleavage (marker of apoptosis) and ERα and cyclin D1 downregulation were discovered in MCF-7 cells treated with lead secosteroid-1,2,4-triazole hybrid 4b. The synthesized secosteroids may be considered as new promising anticancer agents.

A density functional theory study of the molecular structure, reactivity, and spectroscopic properties of 2-(2-mercaptophenyl)-1-azaazulene tautomers and rotamers

Five stable tautomer and rotamers of the 2-(2-Mercaptophenyl)-1-azaazulene (thiol, thione, R1, R2, and R3) molecules were studied using density functional theory (DFT). The geometries of the studied tautomer and rotamers were fully optimized at the B3LYP/6-31G(d,p) level. Thermodynamic calculations were performed at M06-2X/6-311G++(2d,2p) and ωB97XD/6-311G++(2d,2p) in the gas phase and ethanol solution conditions modeled by the solvation model based on density (SMD). The kinetic constant of tautomer and rotamers conversion was calculated in the temperature range 270-320 K using variational transition state theory (VTST) accompanied by one-dimensional wigner tunneling correction. Energy refinement at CCSD(T)/6-311++G(2d,2p) in the gas phase has been calculated. All the studied DFT methods qualitatively give similar tautomer stability orders in the gas phase. The ethanol solvent causes some reordering of the relative stability of 2-(2-Mercaptophenyl)-1-azaazulene conformers. The transition states for the 2-(2-Mercaptophenyl)-1-azaazulene tautomerization and rotamerization processes were also determined. The reactivity, electric dipole moment, and spectroscopic properties of the studied tautomer and rotamers were computed. The hyper-Rayleigh scattering (βHRS), and depolarization ratio (DR) exhibited promising optical properties when nonlinear optical properties were calculated.

A Novel One-Step Reactive Extrusion Process for High-Performance Rigid Crosslinked PVC Composite Fabrication Using Triazine Crosslinking Agent@Melamine-Formaldehyde Microcapsules

In this work, we propose, for the first time, a simple, fast, and efficient strategy to fabricate high-performance rigid crosslinked PVC composites by continuous extrusion. This strategy improves the poor processing fluidity of composites and solves the impossibility of conducting extrusion in one step via using microcapsule-type crosslinking agents prepared by in situ polymerization to co-extrude with PVC blends. The results demonstrate that the PVC/microcapsule composites were successfully prepared. Within the studied parameters, the properties of crosslinked PVC gradually increased with the addition of microcapsules, and its Vicat softening temperature increased from 79.3 °C to 86.2 °C compared with pure PVC. This study shows the possibility for the industrial scale-up of the extrusion process for rigid crosslinked PVC.

Quantum Computational Investigation of (E)-1-(4-methoxyphenyl)-5-methyl-N′-(3-phenoxybenzylidene)-1H-1,2,3-triazole-4-carbohydrazide

The title compound was synthesized and structurally characterized. Theoretical IR, NMR (with the GIAO technique), UV, and nonlinear optical properties (NLO) in four different solvents were calculated for the compound. The calculated HOMO–LUMO energies using time-dependent (TD) DFT revealed that charge transfer occurs within the molecule, and probable transitions in the four solvents were identified. The in silico absorption, distribution, metabolism, and excretion (ADME) analysis was performed in order to determine some physicochemical, lipophilicity, water solubility, pharmacokinetics, drug-likeness, and medicinal properties of the molecule. Finally, molecular docking calculation was performed, and the results were evaluated in detail.

Ultrasound-assisted, low-solvent and acid/base-free synthesis of 5-substituted 1,3,4-oxadiazole-2-thiols as potent antimicrobial and antioxidant agents

One of the goals of green chemistry is to use environmentally friendly solvents or remove and reduce the volume of harmful spent solvents. In this study, a novel process for the synthesis of 5-substituted 1,3,4-oxadiazole-2-thiol derivatives was proposed via ultrasound-assisted reaction of aryl hydrazides with CS2 (1:1 molar ratio) in some drops of DMF in the absence of basic or acidic catalysts. They were produced in good to excellent yields under easy workup and purification conditions. In order to prove the usefulness of the prepared compounds, their antioxidant, antibacterial, and antifungal potentials were screened by DPPH free radical scavenging, serial twofold microdilution and streak plate methods. Acceptable to significant inhibitory activities were observed with synthesized heterocycles. The results showed that 5-(4-fluorophenyl)-1,3,4-oxadiazole-2-thiol (3c) is an broad-spectrum antimicrobial agent. Many of them displayed remarkable antioxidant properties comparable to standard controls (ascorbic acid and α-tocopherol). Synthesized 1,3,4-oxadiazoles are also potent candidates to treat cancer, Parkinson, inflammatory, and diabetes diseases. Eighteen 5-substituted 1,3,4-oxadiazole-2-thiol derivatives as potent antimicrobial and antioxidant agents were prepared via a new, efficient and green procedure.

Synthesis, structural, spectral, antioxidant, bioactivity and molecular docking investigations of a novel triazole derivative

The structural, spectroscopic and electronic properties of 4-(4-nitrophenyl)-5-(pyridin-3-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione have been analyzed by using single crystal X-ray diffraction (SCXRD), ¹H and ¹³C NMR chemical shifts and FT-IR spectroscopic methods both theoretically and experimentally. The tautomeric (thiol and thione) energetic analysis results, structural optimization parameters (bond lengths and angles), vibrational wavenumbers, proton and carbon NMR chemical shifts, UV-Vis. parameters, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) analyses and Molecular Electrostatic Potential (MEP) surface have been calculated by using DFT/B3LYP quantum chemical method with 6-311++G(2d,2p) basis set to compare with the experimental results. The computed geometry parameters, vibrational wavenumbers, and NMR chemical shifts have been in good agreement with the experimental results. It should be noted that the radical scavenging activities of the title compound have been evaluated by using different test methods i.e. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS). According to obtained results, the title compound displayed DPPH (SC₅₀ 19.42 ± 0.11 μg/mL), DMPD (SC₅₀ 21.13 ± 0.08 μg/mL) and ABTS (SC₅₀ 38.17 ± 0.25 μg/mL) scavenging activities. Also, these results have been compared with Butylated hydroxyanisole (BHA), Rutin (RUT) and Trolox (TRO) used as standard compounds. The physicochemical, pharmacokinetic, and toxicity features of the compound have been determined by using drug-likeness and in silico ADMET investigations. The interaction results with SARS-CoV-2 main protease (M^pro) of the title ligand compound have been analyzed via the help of molecular docking study.Communicated by Ramaswamy H. Sarma.

Synthesis, spectroscopic (FT–IR and UV–Vis), crystallographic and theoretical studies, and a molecular docking simulation of an imatinib-like template

The aim of the present study was to report the crystal structure and spectroscopic, electronic, supramolecular and electrostatic properties of a new polymorph of 4-(pyridin-2-yl)pyrimidin-2-amine (C9H8N4). The compound was synthesized under microwave irradiation. The single-crystal X-ray structure analysis revealed an angle of 13.36 (8)° between the planes of the rings, as well as molecules linked by Nsp 2—H...N hydrogen bonds forming dimers along the crystal. The material was analyzed by FT–IR vibrational spectroscopy, while a computational approach was used to elucidate the vibrational frequency couplings. The existence of Nsp 2—H...N hydrogen bonds in the crystal was confirmed spectroscopically by the IR peaks from the N—H stretching vibration shifting to lower wavenumbers in the solid state relative to those in the gas phase. The supramolecular studies confirmed the formation of centrosymmetric R 2 2(8) rings, which correspond to the formation of dimers that stack parallel to the b direction. Other weak C—H...π interactions, essential for crystal growth, were found. The UV–Vis spectroscopic analysis showed a donor–acceptor process, where the amino group acts as a donor and the pyridine and pyrimidine rings act as acceptors. The reactive sites of the molecule were identified and their quantitative values were defined using the electrostatic potential model proposed in the multifunctional wave function analyzer multiwfn. The calculated interaction energies between pairs of molecules were used to visualize the electrostatic terms as the leading factors against the dispersion factors in the crystal-growth process. The docking results showed that the amino group of the pyrimidine moiety was simultaneously anchored by hydrogen-bonding interactions with the Asp427 and His407 protein residues. This compound could be key for the realization of a series of syntheses of molecules that could be used as possible inhibitors of chronic myelogenous leukemia.

New bis 1,3,4-oxadiazole derivatives: syntheses, characterizations, computational studies, and antioxidant activities

In this study, two new bis oxadiazole derivatives (2a and 2b) were synthesized. The new compounds were characterized by elemental analyses, IR, 1H NMR, 13C NMR, and mass spectral studies and were tested for their antioxidant activity. According to the results, it was observed that the synthesized compounds (2a and 2b) had a very high activity in both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing ability of plasma (FRAP) tests. The approximate geometries of the compounds 2a and 2b were prepared with GaussView5 visualization program. The optimized molecular geometric parameters, vibrational wavenumbers, UV–vis parameters, and HOMO–LUMO simulations were computed using Gaussian 09W program. The computations were performed at 6-311++G(d,p) basis set using the B3LYP functional in density functional theory (DFT) method. The harmonic vibrational wavenumbers computed in gas phase were scaled with 0.958 (1700–4000 cm−1) and 0.983 (0–1700 cm−1) for the B3LYP/6-311++G(d,p) level. To calculated the UV–vis spectroscopic parameters with TD-DFT method, the compounds 2a and 2b were optimized in DMF and DMSO solvents using the integral equation formalism polarizable continuum model (IEFPCM) method at the B3LYP/6-311++G(d,p) level. The HOMO, LUMO, and UV–vis analyses were studied to interpret intramolecular charge transfers.

Molecular structure, FT IR, NMR, UV, NBO and HOMO-LUMO of 1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile by DFT/B3LYP and PBEPBE methods with LanL2DZ and 6-311++G(d,2p) basis sets

Structural and molecular properties of antidepressants 1-(3-(dimethylamino)propyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile were examined using quantum mechanics of Density Functional Theory (DFT)/B3LYP and PBEPBE methods with 6-311++G(d,2p) and LanL2DZ basis sets to study the therapeutic properties of the drug. For this, the structure of desired material was optimized by the computer calculation method and with the use of powerful Gaussian 09 software. Then the lowest energy value and the bond length, bond angle and dihedral angle between its constituent atoms in the crystal structure of the desired material were measured from the optimized values. Then the amount of positive and negative charges, polarizability and dipole moment of its atoms using Mulliken charge and Natural atomic charges, DFT/B3LYP and PBEPBE methods with 6-311++G(d,2p) and LanL2DZ basis sets were determined and the results were compared with each other for individual atoms and by mentioned methods. Also the type of stretching vibrations and bending vibrations between the constituent atoms of the molecule were specified using mentioned computational methods and FT IR vibrational spectra. The experimental spectrum of this material was taken to determine the functional groups and the computational and experimental values were compared to each other and Nuclear Magnetic Resonance (NMR) was used to specify the isomer shift between the carbons and protons in the presence of polar and nonpolar solvents. Also Natural Bond Orbital (NBO) was used to determine the type of electron transfers in σ→σ∗ and π→π∗ and LP(1)→σ∗ and LP(2)→σ∗ and the amount of hardness and softness in molecule was determined using the difference between ionization energy and electron affinity energy in constituent atoms of that molecule in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and in the presence of solvents H₂O, CH₃CN and C₆H₁₂. UV-Vis spectrum of the drug was taken using DFT/B3LYP and PBEPBE methods with 6-311++G(d,2p) and LanL2DZ basis sets as well as solvents H₂O, CH₃CN and C₆H₁₂ and the associated transmissions were examined.