The Studies Of Structural Modification Of Xanthatin And The Biological Activities Of The Compounds Against Harmful Pests And Microorganisms

The lead compounds xanthatin has been chemcially transformed to two series ofcompounds, to produce10esters and18amides derivatives. The chemical structuresare identified by modern spectroscopic techniques, such as NMR,13C NMR, and massspectrometry. The spectrometric data have been recorded. The biological activities ofthese compounds are tested. Furthermore, by comparing the biological activitiesbetween these two series, the relationship between the chemical stuctures and thebiological activities of compounds are reserached. This experiment demonstrates howto explore xanthatin and its derivatives and how to utilize them as botanical pesticidesand fungicides. The research results are as the following:1. A monomeric compound separated from Xanthium is identified by the meansof1H NMR,13C NMR, and spectroscopy (UV, IR, and MS). The spectroscopic dataare compared with standard substances and constants. According to the above analysis,the compound formular is considered to be C15H18O3, whose degree of unsaturation is7and the melting point is114℃. In order to determine whether the compound isxanthatin, we analyze the spectral data and the physical properties of the compound,and compare these data with those of standard substances. The results confirm thatthis substance is xanthatin.2. To improve the stability and lipid solubility of xanthatin, the keto group of thechemical stucture of xanthatin is chemically transformed. The major transformationincludes two aspects. First, the ketone carbonyl of xanthatin is reduced to a hydroxylgroup, before the new obtained hydroxyl reacts with common carboxylic acids. Then,a series of esters are produced. Second, the ketone cabonyl of xanthatin reacts withhydrazide, to obtain a series of hydrazide compounds. Utilizing the modernspectroscopic techniques, the data of1H NMR,13C NMR, and mass sepctrometry of the two series of compounds are attained. By analyzing these spectrometric data, thechemical structures of these compounds are identified. In these compounds, somechiral isomers are acquired. Some compounds have achieved purity of crystal.3. Using Alternaric solani, Fusarium oxysporum, and Merulius lacrymans as thetest fungi, the antifungal activities of the esters which have been chemically modifiedare tested. Using Tetranychus urticae and Mythimna separata as test insects, thepesticidal activites of the hydrazide compounds which have been chemically modifiedare also tested. The results display that the transformation of the ketone carbonyl ofxanthatin improves the biological activity. The10kinds of ester compounds havediverse antifungal activities on these four fungi. Among these ester compounds, b6and b7have powerful antifungal activities on Alternaric solani. The b6can alsoprevent the other three fungi. That means b6is a broad-spectrum fungicide. Thebiological activities of these derivatives on Tetranychus urticae and Mythimnaseparata are also tested by indoor bioassay. The results show that C7, C5, and C14have not only high contact toxicities on Tetranychus urticae, but also highnon-selective antifeedant activities, contact toxicities, and stomach toxicities onMythimna separata. These compounds have prospective applications. All of theaforementioned theories pave the way for further study of new botanical pesticidesand fungicides.