Synthesis, Molecule Structure, Thermal Analysis, Non-isothermal Decomposition Kinetics, Bioactivity And Theoretical Study On N-substituted Formyl Thioureas Compound

N' -(l,2,4-triazol-5-one-4-yl)-N-substituted formyl thioureas and N' -(substituted pyrimidin-2-yl)-N-substituted formyl thioureas were synthesized and their structure were characterized by elemental analysis, IR and NMR. Five kinds Single crystal of N-substituted formyl thioureas compound were cultured. Crystal structures were determined by X-ray diffraction analysis. Theirs thermal behaviors were studied by DSC and TG/DTG on SDT Q600 and TGA/SDTA851~e Calorimetry. The kinetic parameters and mechanism function were determined by non-isothermal method.The bactericidal activity of N-substituted formyl thioureas compound were studied by microbe of Gibberella saubinetii, Gibberella nicotiancola and Apple black fruit rot fermentation test and obtained theirs EC50 and EC95 value.The experimental geometry of N' -(l,2,4-triazol-5-one-4-yl)-N-substituted formyl thioureas and N' -(substituted pyrimidin-2-yl)-N-substituted formyl thioureas were used as the initial geometry and optimized with Gaussian 03W. Their calculated bond distances, bond angles and IR frequencies were compared with the experimental values and the theoretical values were in accord with those of the experimental. The structural characters and structure-activity relationships were analyzed according to the calculation results.The quantum chemistry study on the N-substituted formyl thioureas compound shows: (1) There was close relationship between the active groups of the compounds and theiractivities;(2) The calculated results were in good agreement with the experimental ones, which reflect the structure-activity relationship very well;(3) The research methods of basising the relationship of the molecular structure and bioactivity were founded, which made the synthesis of this kind of compounds have definite purpose and direction. Therefore, new applied breed can be designed on purpose and the research cost of bactericide can be reduced.