Asymmetric 1,3,4-oxadiazole derivatives containing naphthalene and stilbene units: synthesis, optical and electrochemical properties

Selenylated-oxadiazoles as promising DNA intercalators: Synthesis, electronic structure, DNA interaction and cleavage

A series of selenylated-oxadiazoles were prepared and their interaction with DNA was investigated. The photophysical studies showed that all the selenylated compounds presented absorption between 270 and 329 nm, assigned to combined n→π* and π→π* transitions, and an intense blue emission (325-380 nm) with quantum yield in the range of Φ _F = 0.1-0.4. DFT and TD-DFT calculations were also performed to study the likely geometry and the excited state of these compounds. Electrochemical studies revealed the ionization potential energies (-5.13 to -6.01 eV) and electron affinity energies (-2.25 to -2.83 eV), depending directly on the electronic effect (electron-donating or electron-withdrawing) of the substituent attached to the product. Finally, the UV-Vis DNA interaction experiments indicated that the compounds can interact with the DNA molecule due to intercalation, except for 3g (which interacted via electrostatic interaction). Plasmid cleavage assay presented positive results only for 3f that presented the strongest interaction results. These results made the tested selenylated-oxadiazoles as suitable structures for the development of drugs and the design of structurally-related therapeutics.

Synthetic approaches toward stilbenes and their related structures

Compounds belonging to the stilbene family have gained remarkable significance in pharmaceutical as well as material chemistry. The current review covers the various synthetic approaches for the syntheses of stilbene scaffold and related structures over last 30 years. In addition, this review also highlights the role of stilbene intermediates used in the synthesis of important molecules with diverse applications in the field of pharmaceutics and material science.

Synthesis, biological evaluation, and structure-activity relationship study of novel stilbene derivatives as potential fungicidal agents

A total of 22 novel stilbene derivatives containing the 1,3,4-oxadiazole moiety and trimethoxybenzene were designed and synthesized. Their chemical structures were characterized by (1)H and (13)C nuclear magnetic resonance, infrared, and high-resolution mass spectrometry. Bioassay results revealed that some of the title compounds showed potent in vivo fungicidal activities against three phytopathogenic fungi (Pseudoperonospora cubensis, Colletotrichum lagenarium, and Septoria cucurbitacearum) from cucurbits at 600 μg/mL. Notably, compounds 4b, 4d, 4i, 4k, and 4l exhibited a broad spectrum and remarkably high activities against those fungi, some of which even showed a comparable control efficacy to that of the commercial fungicides. Three-dimensional quantitative structure-activity relationship based on comparative molecular field analysis with good predictive ability (q(2) = 0.516; r(2) = 0.920) was reasonably discussed. For the first time, the present work suggested that the stilbene derivatives containing the 1,3,4-oxadiazole moiety could be developed as potential fungicides for crop protection.