Nitrogen-containing Heterocyclic Compounds, Structure, Biological Activity, Thermodynamics, Thermal And Quantum Chemical Study

A series of heterocyclic nitrogen compounds—Ⅰ～Ⅻ,Ⅰ:N-methylacyl -N'-pymidin--yl)thiourea;Ⅱ: N-ethylacyl-N'-(pymidin-2-yl)thiourea;Ⅲ: N-benzo yl-N'-(pymidin-2-yl)thiourea;Ⅳ:N-methoxylacyl-N'-(4,6-dimethxoyl-pymidin-2-yl )thiourea;Ⅴ:N-ethoxylacyl-N'-(4,6-dimethxoyl-pymidin -2-yl)thiourea;Ⅵ: N-benzoyl-N'-(4,6-dimethxoyl-pymidin-2-yl)thiourea;Ⅶ:N-methoxylacyl-N'-(1,2,4-triazole-5-one-2-yl)thiourea; N-ethoxylacyl-N'-(1,2,4-triazole-5-one-2-yl)thioure a;Ⅸ:N-benzoyl-N'-(1,2,4-triazole-5-one-2-yl)thiourea;Ⅹ:N-methoxylacyl-N'-(4,6-dimethyl-pymidin-2-yl)thiourea;Ⅺ:N-ethoxylacyl-N'-(4,6-dimethyl-pyrimidi n-2-yl)thiourea;Ⅻ:N-benzoyl-N'-(4,6-dimethyl-pyrimidin-2-yl)thiourea,were synthesized with combinatorial chemistry method—taking pyrimidine and triazole compounds containing nitrogen heterocycles as a lead compound, and isothiocyanate as a modifying group. Their structures have been confirmed by elemental analysis and FT-IR. A new imidazole derivation with nitrogen heterocyclic,2-methyl-3-(2,4-dichlorobenzyl)-5-nitryl imidazole(MNI), was synthesized with analogue synthesis method and determined by IR and elemental analysis. A new metal complex was prepared and its single crystal structure was determined.The dissolvable capability of the compoundsⅠ～ⅩI in organic solvent: cycloexylamine, n-heptane, benzene, toluene, 1,2-dichloroethane, chloroform, dichloromethane, methanol, ethanol, propanol, n-butyl alcohol, nitromethane, acetonitrile,formamide,dimethylformamide,1,4-dioxane,tetrahydrofuran,dimeth ylsulfoxide were studied.The single crystals of the compoundsⅠ,Ⅱ,Ⅴ,Ⅵ,Ⅸand MNI were obtained by slow evaporation of a solvent at room temperature for the first time and their crystal structure were determined with a X-ray diffractometer.The bioactivity of the compoundsⅠ,Ⅱ,Ⅲ,Ⅴ,　ⅥandⅨwere studied by microbe of Gibberella nicotiancola and Apple black fruit rot, and the effects of several compounds on wheat growth were studied. The relationship between the structure and the bioactivity has been discussed. The specific heat capacity of the several compoundsⅠ～Ⅺ,Ⅸ,Ⅹwere determined within 243~345K by a microcalorimetry method, and their thermodynamic functions were obtained. The DSC and TG/DTG techniques were used to study the thermal behavior of the compoundsⅠ,Ⅱ,ⅤandⅥ.The geometries of the compoundⅠ,Ⅱ,Ⅲ,Ⅴ,Ⅵ,Ⅸand MNI were fully optimized with Gaussian. The calculated bond distances, bond angles, IR frequencies were compared with the experimental values and the theoretical values were in accord with those of the experimental. The relationship between the atomic charges, the percentage of frontier orbital compositions and bioactivity were discussed.