The Synthesis And Characterization Of1,3,5-Oxadiazines And Carbazole Derivatives

In the thesis, the synthetic route of thiamethoxam with2,3-dichloropropene and nitroguanidine were majorization. Eleven1,3,5-oxadiazines derivatives were designed and synthesized with3-methyl-4-nitro-imine-1,3,5-oxadiazine. The compounds were characterized by means of1H NMR, MS, IR and X-ray diffraction methods. It was found that the halogens of the halogenated hydrocarbon have an important influence on the reaction time and the yield. The antibacterial activity of the I,3,5-oxadiazin compounds were tested on Staphylococcus aureus. The results showed that antibacterial activity of the compounds is in the range of98.9%-91.4%. The structures of these compounds showed that the compounds with strong electron-withdrawing groups have higher antibacterial properties. This provides scientific evidence for the synthesis of1,3,5-oxadiazin derivatives with high antibacterial activity.The density functional theory methods were employed to calculate the molecular geometries, frontier molecular orbitals, molecular charge distribution, global and local reactivity descriptors of thiamethoxam and other1,3,5-oxadiazine derivatives. The results showed that the antibacterial properties of1,3,5-oxadiazole triazine derivatives are concerned with energy of molecular’s HOMO and LUMO orbital, molecular electronegativity and molecular charge distribution. It is revealed that1,3,5-oxadiazine which with electron-withdrawing groups could increase the antibacterial activity.A series of carbazole derivatives with the imidazole ring were synthesized used carbazole. The products were characterized by means of1H NMR, MS, IR and UV-Vis spectra. The DFT were performed using Gaussian09program bagage. All geometries and energies were calculated using CAM-B3LYP functional with6-31+G (d) basis set. The frontier molecular orbitals, the HOMO-LUMO gap were analysised. Electronic absorption spectras were calculated using TD-DFT. It is found that the substituent groups on the imidazole ring have an effect on some properties, such as soft, hardness, chemical potential, electron affinity, HOMO and LUMO energy et al. Compared with other carbazole derivatives,3-(4,5-diphenyl-1H-imidazol-2-yl)-9H-carbazole (5g) has the biggest chemical reaction activity;3-(4,5-diphenyl-1H-imidazol-2-y1)-9-methyl-carbazole-benzene (5d) have the best electrophilic performance. Therefore, it should be obtain carbazole derivatives with the ideal physical, chemical, biological properties using change the groups on the carbazole.