Synthesis And Biological Activity Of α-campholenic Aldehyde-based Triazole-Thioether And Thiadiazole-Phosphonate Compounds

Turpentine is a renewable,natural and preponderant resource of China,and its main constituent is α-pinene.α-Campholenic aldehyde can be prepared by epoxidation and catalytic isomerization of α-pinene.α-Campholenic aldehyde and its derivatives show a wide range of biological activities.Various bioactive compounds can be synthesized by chemical modification of the characteristic functional groups in α-campholenic aldehyde.In this thesis,a-campholenic aldehyde was prepared by epoxidation and catalytic isomerization of α-pinene at first.Then,two types of novel α-campholenic aldehyde-based derivatives with potential biological activity,a-campholenic aldehyde-based triazole-thioethers and α-campholenic aldehyde-based thiadiazole-phosphonates,were designed and synthesized by chemical modification of the aldehyde group inα-campholenic aldehyde,and by introduction of active triazole,thioether,thiadiazole,and phosphonate groups into the skeleton of α-campholenic aldehyde.This study aims at providing a new way for deep development and utilization of α-campholenic aldehyde.1.α-Campholenic acid 4 was prepared by the oxidation of αα-campholenic aldehyde 3 which was obtained by the epoxidation and catalytic isomerization ofα-pinene.Then,a-campholenic aldehyde-based methyl amide thiourea 5 was prepared by the reaction of α-campholenic acid 4 with 4-methylthio-semicarbazide,followed by the cyclization of 5 and the substitution reaction to afford sixteen novel α-campholenic aldehyde-based triazole-thioether compounds 6a～6p.The synthetic conditions were investigated preliminarily,and the target products were analyzed and characterized by techniques of FT-IR,1H NMR,13C NMR,and ESI-MS.2.α-Campholenic aldehyde-based thiosemicarbazone 7 was prepared by the reaction of a-campholenic aldehyde 3 with thiosemicarbazide.Then,α-campholenic aldehyde-based thiadiazole 8 was prepared by the cyclization reaction of 7,followed by the Mannich-type reaction of 8 with a series of aldehydes and triphenyl phosphate to yield eleven novel a-campholenic aldehyde-based thiadiazole-phosphonate compounds 9a～9k.The synthetic conditions were investigated preliminarily,and the target products were analyzed and characterized by techniques of FT-IR,1H NMR,13C NMR,and ESI-MS.3.The herbicidal activity of all the target compounds 6a～6p and 9a～9k was evaluated by rape petri dish method and barnyard grass beaker method.It was found that,at the concentration of 100 μg/mL,all the target compounds 6,except 6j(R=p-MeBn)and 6k(R=o-CIBn),exhibited growth inhibition rate of greater than 80.0%(A-class activity level)against rape root(Brassica campestris),and all the target compounds 6a～6p showed better growth inhibition activity than the positive control flumioxazin against rape root(Brassica campestris).4.The antifungal activity of all the target compounds 6a～6p and 9a～9k against Physalospora piricola,Alternaria solani,Fusarium oxysporum f.cucumerinum,Gibberella Zeae,and Cercospora arachidicola was evaluated by in vitro method.It was found that,at the concentration of 50 μg/mL,the target compounds 6a～6p exhibited a certain inhibition activity against the five tested fungi,in which compound 6i(R=m-MeBn)had inhibition rate of 75.5%and 78.6%(B-class activity level)against Alternaria solani and Gibberella Zeae,respectively.The target compounds 9a～9k showed weak inhibition activity against the five tested fungi,in which compound 9b(R=p-MeOPh)had inhibition rate of 60.5%(C-class activity level)against Physalospora piricola.