Synthesis, crystal structure, biological activity and theoretical calculations of novel isoxazole derivatives

• A novel series of isoxazole derivatives were first synthesized and evaluated against four plants pathogenic fungi.
• The calculated and experimental data on geometric parameters, FT-IR and FT-Raman spectra of the molecule 3a were studied.
• The HOMO–LUMO and NBO of the compound 3a were being presented.

Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime with 1,3-dipolar cycloaddition. The target compounds were determined by melting point, IR, 1H NMR, elemental analyses and HRMS. The crystal structure of compound 3a was detected by X-ray diffraction and it crystallizes in the triclinic space group p2(1)/c with z = 4. The molecular geometry of compound 3a was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d,p) basis set in the ground state. From the optimized geometry of the molecule, FT-IR, FT-Raman, HOMO–LUMO and natural bond orbital (NBO) were calculated at B3LYP/6-31G+(d,p) level. Finally, the antifungal activity of the synthetic compounds were evaluated against Pythium solani, Gibberella nicotiancola, Fusarium oxysporium f.sp. niveum and Gibberella saubinetii.

Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime. The crystal structure of compound 3a was detected by X-ray diffraction. The molecular geometry of compound 3a was optimized using density functional theory. HOMO–LUMO and natural bond orbital (NBO) were calculated with B3LYP/6-31G+(d,p) level. The antifungal activity of all the synthetic compounds were evaluated against four plants Pathogenic fungis.Figure optionsDownload as PowerPoint slide