Design, Synthesis, in†vitro and in silico Characterization of 2-Quinolone-L-alaninate-1,2,3-triazoles as Antimicrobial Agents.

Due to the ever-increasing antimicrobial resistance there is an urgent need to continuously design and develop novel antimicrobial agents. Inspired by the broad antibacterial activities of various heterocyclic compounds such as 2-quinolone derivatives, we designed and synthesized new methyl-(2-oxo-1,2-dihydroquinolin-4-yl)-L-alaninate-1,2,3-triazole derivatives via 1,3-dipolar cycloaddition reaction of 1-propargyl-2-quinolone-L-alaninate with appropriate azide groups. The synthesized compounds were obtained in good yield ranging from 75 to 80 %. The chemical structures of these novel hybrid molecules were determined by spectroscopic methods and the antimicrobial activity of the compounds was investigated against both bacterial and fungal strains. The tested compounds showed significant antimicrobial activity and weak to moderate antifungal activity. Despite the evident similarity of the quinolone moiety of our compounds with fluoroquinolones, our compounds do not function by inhibiting DNA gyrase. Computational characterization of the compounds shows that they have attractive physicochemical and pharmacokinetic properties and could serve as templates for developing potential antimicrobial agents for clinical use.

Crystal structure, Hirshfeld surface analysis and inter-action energy and DFT studies of 4-[(prop-2-en-1-yl-oxy)meth-yl]-3,6-bis-(pyridin-2-yl)pyridazine.

The title compound, C18H16N4O, consists of a 3,6-bis-(pyridin-2-yl)pyridazine moiety linked to a 4-[(prop-2-en-1-yl-oxy)meth-yl] group. The pyridine-2-yl rings are oriented at a dihedral angle of 17.34 (4)° and are rotated slightly out of the plane of the pyridazine ring. In the crystal, C-HPyrd⋯NPyrdz (Pyrd = pyridine and Pyrdz = pyridazine) hydrogen bonds and C-HPrp-oxy⋯π (Prp-oxy = prop-2-en-1-yl-oxy) inter-actions link the mol-ecules, forming deeply corrugated layers approximately parallel to the bc plane and stacked along the a-axis direction. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (48.5%), H⋯C/C⋯H (26.0%) and H⋯N/N⋯H (17.1%) contacts, hydrogen bonding and van der Waals inter-actions being the dominant inter-actions in the crystal packing. Computational chemistry indicates that in the crystal, the C-HPyrd⋯NPyrdz hydrogen-bond energy is 64.3 kJ mol-1. Density functional theory (DFT) optimized structures at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Synthesis and Downstream Reactions of 2-(Triphenylphosphino)-4,5-dicarbomethoxy-1,3-diselenole Tetrafluoroborate: X-ray Crystal Structure of a Nitroso Derivative of a 2-Ylidene-1,3-diselenole Stabilized by an Intramolecular O.Se Interaction.

The title 1,3-diselenole Wittig reagent 9 has been synthesised by a new, efficient route from readily-available starting materials and reacted with a variety of functionalized aldehydes to form the corresponding 2-ylidene-1,3-diselenones 12 in respectable yields. X-ray analysis of a nitrosated derivative 14e, prepared by the reaction of 12e with isoamyl nitrite, has provided the first direct evidence for the stabilization of such systems by intramolecular oxygen-selenium interactions.