Ether And Benzothiazole Derivatives Of Thiourea Derivatives Synthesis, Structure, Thermal Analysis, Biological Activity And Theoretical Study

Thiourea compounds have a lot of advantages and the widespread application value and prospects. Because of the excellent anti-bacterial nature, favorable bioactivity and structure stabilization properties, many thiourea compounds are being used to make a new-style of pesticide. A subset of these compounds, six in all, have been synthesized and are being studied for these applications.Of the six compounds synthesized two were dithiourea compounds and four benzothiazol thiourea compounds, show below:Two dithiourea compounds:4,4'-bis(3-N-methoxyformyl thioureido)-diphenyloxide4,4'-bis(3-N-p-methxoylbenzoyl thioureido)-diphenyloxideFour benzothiazol thiourea compounds:(N-benzothiazol-2-base-N'-methlacyl)-1-Thiourea(N-benzothiazol-2-base-N'-benzoyl)-1-Thiourea(N-benzothiazol-2-base-N'-ethoxyacyl)-1-Thiourea(N-benzothiazol-2-base-N'-methxoylbenzoyl)-1-ThioureaAll these six compounds were characterized by IR, elemental analysis, and 1HNMR. Single crystals of five compounds were obtained by the slow solvent evaporation method at room temperature. Their crystal structures were obtained using a four-circle X-ray diffractometer.The specific heat capacity of the aforementioned six compounds were determined using continuous Cp mode, with a Micro-DSC III micro-heat instrument at 298.15 K. The enthalpy, entropy and Gibbs free energy of compounds were calculated for temperatures between 283 K and 353 K, relative to the standard temperature 298.15 K. The TG-DSC methods were used to study the thermal behaviors and heat decomposition mechanisms of the above six compounds. The TG/DSC curve of the 6 compounds will provide a stable foundation for later study of these complexes. This reference can be used for quality control purposes in pesticide development.The geometries and enthalpy of formation of these compounds were fully optimized with the Gaussian 03 package, the frontier orbital energies and natural atomic charges are tabulated. The stability observed experimentally is in good agreement with results from calculations done using theory.The bioactivity of these 6 compounds were studied with, Botrytis cinerea, Rhizoctonia solani and Altemaria alternate. The effects of several compounds on mung bean growth were also studied. Thermogenic growth curves of the aforementioned cultures were determined by microcalorimetry and analyzed by computer. Results showed improved antimicrobial activity of benzothiazol thiourea compounds when compared to dithiourea compounds.