Synthesis of Novel Symmetrical 1,4-Disubstituted 1,2,3-Bistriazole Derivatives via 'Click Chemistry' and Their Biological Evaluation.

A series of symmetric bis-1,2,3-triazole compounds 2-5(a-f) were synthesized as potential antioxidant agents via click chemistry. Their structures were confirmed by ¹H-NMR and (13)C-NMR. All of the synthesized compounds were subjected to antioxidant and antimicrobial assays. The antioxidant activity of these compounds (AChE inhibition, DPPH and SOD activities) was evaluated. Compound 2f was found to show the highest AChE inhibition activity of all compounds, while compound 3b showed a strong inhibitory effect on DPPH radical and compound 2a was the most effective of all compounds for SOD activity. All synthesized compounds were found to possess moderate antibacterial activity against the bacteria E. coli and Y.pseudotuberculosis.

Synthesis and biological properties of novel triazole-thiol and thiadiazole derivatives of the 1,2,4-Triazole-3(5)-one class.

2,2'-(4,4'(Butane-1,4-diyl/hexane-1,6-diyl)bis(3-methyl-5-oxo-4,5-dihydro-1,2,4- triazole-4,1-diyl)) diacetohydrazides 3a,b were obtained via the formation of diethyl 2,2'-(4,4'(butane-1,4-diyl/hexane-1,6-diyl)bis(3-methyl-5-oxo-4,5-dihydro-1,2,4-triazole-4,1- diyl))diacetates 2a,b, obtained starting from di-[3(methyl-2-yl-methyl)-4,5-dihydro-1H-[1,2,4]-triazole-5-one-4yl]-n-alkanes 1a,b in two steps. The synthesis of the compounds 7a,b-9a,b incorporating the 1,3,4-thiadiazole, and 10a,b-11a,b with a 1,2,4-triazole-thiol nucleus as the second heterocycle, was performed by the acidic or basic treatment of compounds 4a,b-6a,b which were obtained from the reaction of 3a,b with several isothiocyanates. Newly synthesized compounds were screened for antimicrobial activities and their antioxidant properties by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging method. Compounds 4a,b, 5a,b, and 6a,b were found to possess good antioxidant properties. Almost all compounds have significant antimicrobial activities.

Synthesis, structural characterization and comparison of experimental and theoretical results by DFT level of molecular structure of 4-(4-methoxyphenethyl)-3,5-dimethyl-4H-1,2,4-triazole.

4-(4-Methoxyphenethyl)-3,5-dimethyl-4H-1,2,4-triazole (3) was synthesized from the reaction of ethyl N'-acetylacetohydrazonate (1) with 2-(4-methoxyphenyl)ethanamine (2). The structure of the title compound 3 has been inferred through IR, (1)H/(13)C NMR, mass spectrometry, elemental analyses and combination of X-ray crystallography and theoretical methods. In addition to the molecular geometry from X-ray determination, the molecular geometry and vibrational frequencies of the title compound 3 in the ground state, were calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure and the theoretical vibrational frequencies show good agreement with experimental values. The nonlinear optical properties are also addressed theoretically. The predicted nonlinear optical properties of 3 are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of the title compound were carried out at the B3LYP/6-31G(d) level of theory.

1,1,2,2-Tetra-kis[2,4-dichloro-6-(dieth-oxy-meth-yl)phen-oxy-meth-yl]ethene.

In the title compound, C(50)H(60)Cl(8)O(12), the mol-ecules are disordered about an inversion center located at the mid-point of the central C=C bond. These atoms show disorder and were modelled with two different orientations with site occupancies of 0.828 (3) and 0.172 (3). The dihedral angle between the two benzene rings in the asymmetric unit is 52.80 (6)°. Intramolecular C-H⋯O and C-H⋯Cl interactions occur and the crystal packing features inversion dimers linked by pairs of C-H⋯O bonds, generating R(2) (2)(10) loops.

3-Ethyl-4-[3-(1H-imidazol-1-yl)prop-yl]-5-phenyl-4H-1,2,4-triazole dihydrate.

In the title compound, C(16)H(19)N(5)·2H(2)O, the triazole ring makes dihedral angles of 70.61 (6) and 41.89 (8)°, respectively, with the imidazole and benzene rings. The water mol-ecules are involved in inter-molecular O-H⋯N and O-H⋯O hydrogen bonds, which stabilize the crystal packing.