Synthesis And Biological Activity Of α-Campholenic Aldehyde-based Thiadiazole-amide And Amide-sulfonamide Compounds

a-Pinene is a natural and preponderant biomass resource of China.α-Campholenic aldehyde can be prepared by epoxidation and catalytic isomerization of a-pinene,and its derivatives show a certain biological activity.Various bioactive derivatives can be synthesized by structural modification of a-campholenic aldehyde.In this thesis,a-pinene was converted into a-campholenic aldehyde at first.Then,two types of novel α-campholenic aldehyde-based derivatives with potential biological activities,2-sustituted acylamino-5-α-campholenic aldehyde-based-1,3,4-thiadiazoles and N-(4-substituted amino-sulfonyl)-phenyl-a-campholenamides,were designed and synthesized by modification reactions of aldehyde group in a-campholenic aldehyde,and by introduction of active 1,3,4-thiadiazole,amide and sulfonamide groups into the skeleton of a-campholenic aldehyde.This research aims at providing a new way for deep development and utilization of α-pinene.In this thesis,a-campholenic aldehyde 3 was prepared by epoxidation and catalytic isomerization of a-pinene at first.Then,a-campholenic aldehyde-based thiadiazole 5 was prepared by cyclization reaction of a-campholenic aldehyde-based thiosemicarbazone 4,which was obtained by reaction of thiosemicarbazide with a-campholenic aldehyde.Finally,twelve novel 2-sustituted acylamino-5-α-campholenic aldehyde-based-1,3,4-thiadiazole componds 6a-61 were synthesized by N-acylation reaction of α-campholenic aldehyde-based thiadiazole with a series of acyl chlorides.Besides,α-campholenic acid 7 was prepared by oxidation reaction of a-campholenic aldehyde and converted into its chloride 8,followed by N-acylation reaction of 8 with various sulfonamides compounds to afford eight novel N-(4-substituted amino-sulfonyl)-phenyl-α-campholenamide compounds 9a-9h.All the target compounds 6 and 9 were analyzed and characterized by means of ESI-MS,FT-IR,IH-NMR and 13C-NMR spectral techniques.The antifungal activity of all the target compounds 6a-61 and 9a-9h was evaluated by in vitro method against Fusarium oxysporum f.cucumerinum,Cercospora arachidicola,Physalospora piricola,Alternaria solani,and Gibberella Zeae.It was found that,at the concentration of 50 μg·mL-1,compound 6b(R=ClCH2)exhibited excellent inhibition activity of 97.7%(A-class activity level)against Physalospora piricola,which is better than the positive control azoxystrobin.Compounds 6c(R=CH2CH3)and 6a(R=CH3)showed excellent inhibition activity of 94.4%and 91.3%(A-class activity level)against Gibberella Zeae,respectively,in which the former is better than the positive control azoxystrobin and the latter is the same as the positive control azoxystrobin.Therefore,compounds 6b(R=ClCH2),6c(R=CH2CH3)and 6a(R=CH3)are leading compounds worthy of deep research.The synthesized target compounds 9 displayed a certain antifungal activity against the above-mentioned fungi.The herbicidal activity of all the target compounds 6a-61 and 9a-9h was evaluated by barnyard grass beaker method and rape petri method.It was found that,at the concentration of 100 μg·mL-1,most of compounds 6 and a few of compounds 9 showed weak growth inhibition activity against rape root(Brassica campestris).The synthesized target compounds 6 and 9 displayed almost no activity against barnyard grass(Echinochloa crusgalli(L.)).