Synthesis And Biological Activity Of Perillaldehyde-based Oxime Ester And Perillaldehyde-based Schiff Base-thiourea/urea Compounds

Turpentine is a renewable,natural and preponderant resource of China,and its dominant constituent is α-pinene.Perillaldehyde can be prepared by catalytic isomerization of myrtenal obtained via oxidation of the allylic methyl inα-pinene.Perillaldehyde and its derivatives exhibit a wide range of bioactivities.In this thesis,two types of novel perillaldehyde-based derivatives with potential bioactivity,perillaldehyde-based oxime esters and perillaldehyde-based Schiff base-thioureas/ureas,were designed and synthesized by modification reactions of the aldehyde group in perillaldehyde,and by combination of active oxime ester and thiourea/urea moieties with perillaldehyde,using perillaldehyde as starting material.This study aims at providing a new pathway for the deep development and utilization of perillaldehyde.In this thesis,two types of novel perillaldehyde derivatives,comprising thirty-four compounds,were designed and synthesized using perillaldehyde as starting material.The synthetic conditions were investigated preliminarily.The target compounds were analyzed and characterized by techniques of FT-IR,1H NMR,13C NMR,and ESI-MS,and their antifungal and herbicidal evaluation was carried out as well.The major research contens and results are summarized as follows:1.Perillaldehyde with high purity(over 90%by GC)was separated and purified from the crude product purchased from company at first.Then,perillartine was prepared by oximation reaction of perillaldehyde,followed by O-acylation reaction of perillartine with a series of acyl chlorides to give twenty-one perillaldehyde-based oxime ester compounds 3a-3u.2.Tert-Boc hydrazine was treated with a series of isothiocyanates or isocyanates to generate Boc-protected(thio)semicarbazides,which were then deprotected with trifluoroacetic acid to yield(thio)semicarbazides,followed by condensation reaction of(thio)semicarbazides with perillaldehyde to afford thirteen perillaldehyde-based Schiff base-thiourea/urea compounds 7a-7m.3.The antifungal activity of the target compounds 3a-3u and 7a-7m was evaluated by in vitro method against Fusarium oxysporum f cucumerinum,Physalospora piricola,Alternaria solani,Cercospora arachidicola,and Gibberella zeae.It was found that,at the concentration of 50μg/mL,compound 3 b(R=CH2CH3)showed best antifungal activity against the five tested fungi,and it had inhibition rate of 85.0%and 79.2%against Cercospora arachidicola and Physalospora piricola,respectively.Compounds 7a-7m exhibited prominent inhibition activity against Physalospora piricola and Alternaria solani,in which compound 7d(R=phenyl)had inhibition rate of 91.8%(A-class activity level)against Alternaria solani,and compound 7f(R=p-FPh)had inhibition rate of 90.0%(A-class activity level)against Physalospora piricola.Furthermore,substituted phenyl thioureas showed better antifungal activity than substituted phenyl ureas.4.The herbicidal activity of the target compounds 3a-3u and 7a-7m was evaluated by the rape(Brassica campestris)petri dish method and the barnyard grass(Echinochloa crusgalli L.)beaker method.It was found that,at the concentration of 100 μg/mL,compound 3a(R=CH3),3b(R=CH2CH3),and 3f(R=cyclopentyl)had inhibition rate of 97.0%,91.0%,and 80.0%(A-class activity level)against barnyard grass(Echinochloa crusgalli L.),respectively.Compounds 3m(R=p-ClPh)and 3b(R=CH2CH3)displayed better growth inhibition activity of 88.4%and 79.6%(A-class activity level)against root of rape(Brassica campestris),respectively.It was also found that,compounds 7a(R=CH3),7c(R=cyclopentyl),7i(R=p-CH3Ph),and 7j(R=m-OCH3Ph)showed growth inhibition activity of 67.4%,77.6%,75.3%,and 60.7%(B-class activity level)against root of rape(Brassica campestris),respectively.Furthermore,substituted phenyl thioureas showed better herbicidal activity than substituted phenyl ureas.