Thermochemical Study Of Nitrogenous Heterocyclic Compounds With Biological Activity

Nitrogen-containing heterocyclic compounds are important organic compounds, which has a good activity not only in pesticide but also in medicine. Since several decades of years, great progression has been made for synthesis and characterization of structure and properties about the nitrogen-containing heterocyclic compounds in order to make them more suitable for the industrial production. However, the thermodynamics in the synthesis process and the research on the relationship between the structure and the thermodynamic properties of the compounds are quite few. In the present thesis low-temperature heat capacity, heats of combustion and standard molar enthalpies of formation for pyrimidinamine, triazole and benzothiazole compounds have been investigated by a fully automated precision adiabatic calorimeter, a high precision oxygen bomb calorimeter and TG-DSC, respectively. Major measurements and research results are summarized as follows:Nine pyrimidinamine compounds were synthesized with pyrimethanil and biological acid as raw materials and their structures have been confirmed through IR, ~1HNMR and elemental analysis. Their preliminary biological activities have been tested by asp-agar-diluted method. The results of tests showed that most of them exhibited excellent fungicidal activities. The relationship between the structures and the biological activities of the pyrimethanil salts was discussed.Low-temperature heat capacities of the compounds were measured in the temperature range from 80K to 380K by the fully automated adiabatic calorimeter. The thermodynamic data, such as temperatures, enthalpies and entropies of the fusions, have been calculated according to the experimental heat capacities. Valid and virtual section of the heat-capacity curve of the compound was fitted and a...