Synthesis of some new s-alkylated 1,2,4-triazoles, their mannich bases and their biological activities

Design, Synthesis and Antibacterial Assessment of Active (4-Arylazo-3-Methyl-2-Thienyl) 4-Antipyrine Ketones

The chemicals formed from antipyrines are flexible organic building blocks that are employed in the development of pharmaceuticals. By diazotizing (4-arylazo-3-hydroxy-2-thienyl) 4-antipyrine ketones 1a, 1b and 1c and (4-arylazo-3-methyl-2-thienyl) 4-antipyrine ketones (2a, 2b and 2c) further replaced with six other coupling components, a broad spectrum of hybrid molecules have been created. Mass spectra, NMR, FTIR, and elemental analyses have all been used to confirm the structures of the synthesised compounds. The antimicrobial screening was investigated by agar well diffusion and diluting the broth technique against both Gram-negative and positive-tested bacterial strains. (3-methyl-5-(phenylamino)-4-(4-tolylazo)-2-thienyl) 4-antipyrine ketone (2a) was found to be superior to Ciprofloxacin against test strains: Acinetobacter sp (34.33±1.15 mm), Listeria monocytogenes (29.33±1.15 mm) and Streptococcus sp. (19.33±1.15 mm). Also, good to moderate activities were expressed as minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) which were recorded at 9±1 to 59.67±4.51 μg/mL and 16±4 to >512 μg/mL, respectively, using compounds 2a, 2b, and 2c. MBC/MIC ratio showed, that only, 2a and 2b have a bactericidal effect but other antipyrines with bacteriostatic strength. To conclude, it was suggested that the use of these novel synthesized (4-arylazo-3-methyl-2-thienyl) 4-antipyrine ketone derivatives molecules as a new chemical class of antimicrobial agents to perform new drug discovery in pharmaceutical preparations and medicinal research.

Supramolecular Self-Assembly Built by Weak Hydrogen, Chalcogen, and Unorthodox Nonbonded Motifs in 4-(4-Chlorophenyl)-3-[(4-fluorobenzyl)sulfanyl]-5-(thiophen-2-yl)-4H-1,2,4-triazole, a Selective COX-2 Inhibitor: Insights from X-ray and Theoretical Studies

A selective triazole-based COX-2 inhibitor, 4-(4-chlorophenyl)-3-[(4-fluorobenzyl)sulfanyl]-5-(thiophen-2-yl)-4H-1,2,4-triazole, C₁₉H₁₃ClFN₃S₂, has been synthesized, and its crystal structure was determined at 150 K. Single-crystal X-ray diffraction analysis revealed that the thiophene ring was disordered over two orientations. The crystal structure is stabilized by weak hydrogen and chalcogen bonds and unorthodox F···π and S···C(π) contacts. These noncovalent interactions cooperatively generate the supramolecular self-assembly in the crystalline state. The Hirshfeld surface and its associated two-dimensional (2D)-fingerprint plots were obtained to analyze the role of different noncovalent interactions in the crystal packing. Further, the enrichment ratio was obtained from different atom···atom pairs to calculate the propensity of these pairs to form noncovalent interactions. The strength of different dimeric motifs formed in the crystal structure and lattice energies was calculated by the PIXEL method. Furthermore, the topological analysis of the charge density of intermolecular interactions was described. A CSD survey of C–H···F hydrogen bond, C–S···Cl chalcogen bond, and unorthodox nonbonded contacts (F···π and S···C(π)) is presented. The title compound possesses selective inhibitory activity against human COX-2 enzyme rather than COX-1. The quantum mechanics (QM) polarized ligand docking analysis was used to predict the binding pose and study the title compound’s selectivity against COX-1/2 enzymes.

Mannich bases in medicinal chemistry and drug design

The biological activity of Mannich bases, a structurally heterogeneous class of chemical compounds that are generated from various substrates through the introduction of an aminomethyl function by means of the Mannich reaction, is surveyed, with emphasis on the relationship between structure and biological activity. The review covers extensively the literature reports that have disclosed Mannich bases as anticancer and cytotoxic agents, or compounds with potential antibacterial and antifungal activity in the last decade. The most relevant studies on the activity of Mannich bases as antimycobacterial agents, antimalarials, or antiviral candidates have been included as well. The review contains also a thorough coverage of anticonvulsant, anti-inflammatory, analgesic and antioxidant activities of Mannich bases. In addition, several minor biological activities of Mannich bases, such as their ability to regulate blood pressure or inhibit platelet aggregation, their antiparasitic and anti-ulcer effects, as well as their use as agents for the treatment of mental disorders have been presented. The review gives in the end a brief overview of the potential of Mannich bases as inhibitors of various enzymes or ligands for several receptors.

In Silico vibrational spectroscopic investigation on antioxidant active Mannich base 1-[anilino (phenyl) methyl] pyrrolidine-2,5-dione

The antioxidant active Mannich base 1-[anilino (phenyl) methyl] pyrrolidine-2,5-dione (APMPD) have been synthesized and its FT-IR and FT-Raman vibrational spectra were recorded within the region of 4000cm(-1), 50cm(-1) respectively. The molecular geometric parameters of APMPD have been computed using HF and DFT model theories. The energies of APMPD are calculated for all the eight possible conformers using B3LYP method at 6-311++G(d,p) basis set. From the computational results, the M1 conformer was identified as the most stable conformer of APMPD. The stable conformer was compared with experimental crystal geometry, which again fortifies the results of conformer analysis. The fundamental vibrations of the molecule are assigned according to the characteristic region and the literature report. The predicted highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap provide vivid idea on charge transfer behavior of APMPD. The molecular electrostatic potential (MEP) and Mulliken charge analysis indicate the feasible electrophilic and nucleophilic reactive sites on APMPD. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at various temperatures are calculated in gas phase.

Synthesis, antimicrobial, and anti-inflammatory activity, of novel S-substituted and N-substituted 5-(1-adamantyl)-1,2,4-triazole-3-thiols

The reaction of 5-(1-adamantyl)-4-phenyl-1,2,4-triazoline-3-thione (compound 5) with formaldehyde and 1-substituted piperazines yielded the corresponding N-Mannich bases 6a-f. The reaction of 5-(1-adamantyl)-4-methyl-1,2,4-triazoline-3-thione 8 with various 2-aminoethyl chloride yielded separable mixtures of the S-(2-aminoethyl) 9a-d and the N-(2-aminoethyl) 10a-d derivatives. The reaction of compound 5 with 1-bromo-2-methoxyethane, various aryl methyl halides, and ethyl bromoacetate solely yielded the S-substituted products 11, 12a-d, and 13. The new compounds were tested for activity against a panel of Gram-positive and Gram-negative bacteria and the pathogenic fungus Candida albicans. Compounds 6b, 6c, 6d, 6e, 6f, 10b, 10c, 10d, 12c, 12d, 12e, 13, and 14 displayed potent antibacterial activity. Meanwhile, compounds 13 and 14 produced good dose-dependent anti-inflammatory activity against carrageenan-induced paw edema in rats.

Synthesis and biological activities of some novel aminomethyl derivatives of 4-substituted-5-(2-thienyl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones

A novel series of compounds were synthesized by cyclic condensation reaction of substituted isothiocyanate (2a-c) with 2-thiophenecarboxylic acid hydrazide (1) in the presence of ethyl alcohol, to obtain intermediate thiosemicarbazides (3a-c), which were further treated with sodium hydroxide in the presence of ethanol to obtain triazole derivatives (4a-c). The latter were refluxed with substituted secondary amines and formaldehyde for 6-10 h to afford Mannich bases (5a-k). The synthesized compounds were characterized on the basis of their spectral (IR, (13)C and (1)H NMR) data and evaluated for biological activities. Some of the compounds were found to exhibit significant antimicrobial and antioxidant activity.