Antituberculosis agents. I. Alpha-(5-(2-Furyl)-1,2,4-triazol-3-ylthio) acethydrazide and related compounds

Comparative study of molecular docking, structural, electronic, vibrational and hydrogen bonding interactions on 4-hydroxy benzo hydrazide (4HBH) and its newly designed derivative [(E)–N′-((1H-Pyrrol-2-YL)methylene) –4-hydroxy benzo hydrazide and its isomers (I, II and III)] (potential inhibitors) for COVID-19 protease

Studies have shown that hydrazides and thier derivatives are used for pharmaceutical and medicinal purposes. At present, the whole world is suffering for COVID-19 virus. There are some vaccines or medicines available to treat this disease all over the world. Today the one fourth of the world’s population is under lockdown condition. In this scenario, scientists from the whole world are doing different types of research on this disease. Being a molecular modeller, this inspires us to design new types of species (may be drugs) which may be capable for COVID-19 Protease. In the present effort, we have performed docking studies of title compounds with COVID-19 protein (6LU7) for anti-COVID-19 activity. A comparative quantum chemical calculations of molecular geometries (bond lengths and bond angles) of 4-Hydroxy Benzo Hydrazide (4HBH) and its newly designed derivatve [(E)-N′-((1H-Pyrrol-2-YL)Methylene) –4-Hydroxy Benzo Hydrazide and its isomers (I, II and III)] in the ground state have also been carried out due to its biological importance and compared with the similer type of compound found in literature i.e. benzohydrazide. The optimized geometry and wavenumber of the vibrational bands of the molecules have been calculated by density functional theory (DFT) using Becke’s three-parameters hybrid functional (B3LYP/CAM-B3LYP) with 6–311G (d, p) as the basis set. Vibrational wavenumbers are compared with the observed FT-IR and FTRaman spectra of 4-Hydroxy Benzo Hydrazide. TDDFT calculations are also done on the same level of theory and a theoretical UV-vis spectrum of title molecules are also drawn. HOMO-LUMO analysis has been done to describe the way the molecule interacts with other species. Natural bond orbitals (NBO) analysis has been carried out to inspect the intra- and inter- molecular hydrogen-bonding, conjugative and hyper conjugative interactions and their second order stabilization energy. Nonlinear optical (NLO) analysis has been performed to study the non-linear optical properties of the molecule by computing the first hyperpolarizability. The variation of thermodynamic properties with temperature has been studied. QATIM analysis shows that hydrogen bonding occurs in 4HBH, isomer II and III respectively.

Vibrational spectroscopy investigation and density functional theory calculations on (E)-N'-(4-methoxybenzylidene) benzohydrazide

The FT-IR, FT-Raman and UV-Vis spectra of the Schiff base compound (E)-N'-(4-methoxybenzylidene) benzohydrazide (MBBH) have been recorded and analyzed. The optimized geometrical parameters were calculated. The complete vibrational assignments were performed on the basis of TED of the vibrational modes, calculated with the help of SQM method. NBO analysis has been carried out to explore the hyperconjugative interactions and their second order stabilization energy within the molecule. The molecular orbitals (MO's) and its energy gap were studied. The first order hyperpolarizability (β0) and related properties (β, α0, Δα) of MBBH are also calculated. All theoretical calculations were performed on the basis of B3LYP/6-311++G(d,p) level of theory.

Quantum chemical computations, vibrational spectroscopic studies, NLO and NBO/NLMO analysis of o-chlorobenzohydrazide

The molecular vibrations of o-chlorobenzohydrazide (OCBH) have been investigated in polycrystalline sample, at room temperature, by recording Fourier transform infrared (FT-IR) and FT-Raman spectroscopies. The complete vibrational assignment and analysis of the fundamental modes was carried out using the experimental data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the HF and DFT/B3LYP calculations employing 6-311++G(d,p) basis set. The (1)H and (13)C NMR chemical shifts have been simulated. Thermodynamic properties have been calculated at different temperatures. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis.

Synthesis of New [1,2,4]Triazolo[3,4-b][1,3,4]thiadiazines and Study of Their Anti-Candidaland Cytotoxic Activities

New triazolothiadiazine derivatives5a–hwere synthesized from 4-amino-3-(4-pyridyl)-5-mercapto-4H-1,2,4-triazole (3) with substituted aryl hydrazonoyl chlorides4a–h. The compounds were testedin vitroagainst elevenCandidaspecies and compared with standard drug ketoconazole. Among these compounds, the compounds bearingp-chlorophenyl5e,p-methoxyphenyl5c, phenyl5a,andp-sulphonamidophenyl5gsubstituents on triazolothiadiazine system were found to be the most effective derivatives againstCandidaspecies. Compound5ewas the most effective compound againstC. parapsilosis(ATCC 22019),C. albicans(ATCC 66027),C.specie [blood] 12810, andC.specie [urine] 300 with MIC value of 6.25 μg/mL, whereas ketoconazole exhibits the inhibitory activity with MIC value of 3–30 μg/mL against all tested strains. It was clear that there is a positive correlation between anti-Candidalactivity andp-chlorophenyl substitution on triazolothiadiazine ring. All the synthesized compounds were also investigated for their potential cytotoxicity on noncancer cell line (MCF-12) using WST-1 assay. Three compounds5d,5a,and5hwere found to have the same IC50value as that of standard drug ketoconazole against noncancer cell line MCF-12 (IC50≥ 1.0 × 105 μg/mL).

Spectroscopic investigations, quantum chemical calculations, HOMO-LUMO and NBO/NLMO analysis of 4-pyridinecarbohydrazide

The FT-IR and FT-Raman spectra of 4-pyridinecarbohydrazide have been recorded. The complete vibrational assignment and analysis of the fundamental modes was carried out using the experimental data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically for the optimized geometry of the compound from the DFT-B3LYP gradient calculations employing 6-311++G(d,p) basis set. The (1)H and (13)C NMR chemical shifts have been simulated. Thermodynamic properties have been calculated at different temperatures. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis.

Conformational, structural, vibrational and quantum chemical analysis on 4-aminobenzohydrazide and 4-hydroxybenzohydrazide--a comparative study

Experimental and theoretical quantum chemical studies were carried out on 4-hydroxybenzohydrazide (4HBH) and 4-aminobenzohydrazide (4ABH) using FTIR and FT-Raman spectral data. The structural characteristics and vibrational spectroscopic analysis were carried performed by quantum chemical methods with the hybrid exchange-correlation functional B3LYP using 6-31G(**), 6-311++G(**) and aug-cc-pVDZ basis sets. The most stable conformer of the title compounds have been determined from the analysis of potential energy surface. The stable molecular geometries, electronic and thermodynamic parameters, IR intensities, harmonic vibrational frequencies, depolarisation ratio and Raman intensities have been computed. Molecular electrostatic potential and frontier molecular orbitals were constructed to understand the electronic properties. The potential energy distributions (PEDs) were calculated to explain the mixing of fundamental modes. The theoretical geometrical parameters and the fundamental frequencies were compared with the experimental. The interactions of hydroxy and amino group substitutions on the characteristic vibrations of the ring and hydrazide group have been analysed.

Synthesis, FTIR, FT-Raman, UV-visible, ab initio and DFT studies on benzohydrazide

A systematic vibrational spectroscopic assignment and analysis of benzohydrazide (BH) has been carried out by using FTIR and FT-Raman spectral data. The vibrational analysis were aided by electronic structure calculations--ab initio (RHF) and hybrid density functional methods (B3LYP and B3PW91) performed with 6-31G(d,p) and 6-311++G(d,p) basis sets. Molecular equilibrium geometries, electronic energies, IR intensities, harmonic vibrational frequencies, depolarization ratios and Raman activities have been computed. Potential energy distribution (PED) and normal mode analysis have also been performed. The assignments proposed based on the experimental IR and Raman spectra have been reviewed and complete assignment of the observed spectra have been proposed. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λ(max) were determined by time-dependent DFT (TD-DFT) method. The geometrical, thermodynamical parameters and absorption wavelengths were compared with the experimental data. The interactions of carbonyl and hydrazide groups on the benzene ring skeletal modes were investigated.

Synthesis and Biological Evaluation of Fatty Hydrazides of By-products of Oil Processing Industry

Some new 2-alkyl-5-mercapto-1,3,4-Oxadiazoles and 3-alkyl-5-mercapto-1,2,3-4H triazoles were synthesized from hydrazides of acid oil and oil recovered from spent bleaching earth. These newly synthesized compounds were characterized on the basis of elemental analysis and evaluated for biological properties. Certain derivatives exhibited fairly high antibacterial and antifungal activities when compared with streptomycin and immidil used as standard antibacterial and antifungal agents respectively.

New S-alkylated 1,2,4-triazoles incorporating diphenyl sulfone moieties with potential antibacterial activity

Alkylation of the 5-{4-[(4-bromophenyl)sulfonyl]phenyl}-4-(3/4-methylphenyl)- 2,4-dihydro-3H-1,2,4-triazole-3-thiones 3a,b with various alkylation agents, i.e., ethyl bromide, phenacyl bromide and ethyl chloroacetate, afforded the S-substituted 1,2,4-triazoles 4-6a,b. The structures of these new compounds were elucidated by elemental analysis and IR, UV, 1H-NMR, 13C-NMR and MS spectroscopy. The newly synthesized products were tested for their antibacterial effects.

Synthesis and antituberculosis activity of new 3-alkylsulfanyl-1,2,4-triazole derivatives

The increasing clinical importance of drug-resistant mycobacterial pathogens has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new alkylsulfanyltriazoles were synthesized and evaluated for antituberculosis activity. The reaction of thienyl-2-acetic acid with thiocarbohydrazide gave the mercaptotriazoles (II). The 4-amino-5-(2-thienylmethyl)-3-[1-(2-thienyl)-3-aryl) propion-3-yl] sulfanyl-4H-1,2,4-triazole (III) derivatives were synthesized by reacting the mercaptotriazoles with chalcones (I). Antituberculosis activities of the synthesized compounds were determined by broth microdilution assay, the Microplate Alamar Blue Assay, in BACTEC 12B medium and results were screened in-vitro, using BACTEC 460 Radiometric System against Mycobacterium tuberculosis H37Rv (ATCC 27294) at 6.25 microg/ml and the tested compounds showed considerable inhibition ranging from 58-84%.