Synthesis And Characterization Of 4-Fenchylthiosemicarbazone And Its Thiadiazole Derivatives

With the rapid development of chemistry and life sicience, people found that several biologically active therapeutics contain the atom of nitrogen and sulfur in their chemical structure. Thiosemicarbazones as special schiff base, have strong coordination ability, good biological activities and other excellent properties, make them to be potential drugs and functional materials. A considerable attention has been devoted to the synthesis of 1,3,4- thiadiazole derivatives which possess an extensive spectra of biological activities such as herbicide, insecticidal, regulating plant growth, anti-inflammatory, antimicrobial, antiviral, antitumoral, anticonvulsant. So far, there are many reports about the synthesis of 1,3,4- thiadiazole, but there are few reports about the using of chiral thiosemicarbazone as key intermediates. As we known, many drugs are the compounds that contain the chiral group in their chemical structure.(–)-Fenchone is a natural product with native chirality, which can be obtained from the arborvitae leaves and the fennel fruits. In this thesis, we studied on the synthesis and characterization of thiosemicarbazone and 1,3,4-thiadiazole derivatives using (–)-fenchone as the starting material.The thesis is composed of two parts: the summarizations and the experiments.The part of summarizations made a description of the recent reports about the synthesis and biological activities of thiosemicarbazone and 1,3,4- thiadiazole derivatives.The part of experiments: (–)-fenchone reacted with formamide, N-fenchylformamide were got. N-fenchylformamide were hydrolysis by concentrated hydrochloric acid, and then (–)-fenchylamine were obtained. 4-Fenchylthiosemicarbazide were obtained by (–)-fenchyl- amine react with carbon bisulfide and hydrazine hydrate. The resulting thiosemicarbazides were allowed react with aldehyde to finish in yield of >85%. Finally, thiosemicarbazones were cyclized under the catalyzed of potassium ferricyanide, and 1,3,4- thiadiazole derivatives were obtained. The yield of the final compounds ranged from 70% to 95%.In summary, 24 new compounds were synthesized and characterized by IR, NMR and MS in this thesis. The results indicate that the strategy we used has significant advantages, such as mild reaction conditions, safety operations and high yields. Our research set the basis of chemsynthesis for the application of thiosemicarbazones and 1,3,4- thiadiazole derivatives.