Synthesis And Biological Activity Of Maleated Rosin-based Oxadiazole-amide And Dithiourea Compounds

Rosin is an abundant and renewable resource of China.Resin acids in rosin and their derivatives show broad biological activities.In recent years,it has become one of the research focuses for chemistry of organic synthesis to synthesize novel bioactive compounds through structural modification of resin acids in rosin.In this thesis,maleated rosin was prepared using rosin as starting material,and two types of maleated rosin-based derivatives with potential bilogical activities,maleated rosin-based oxadiazole-amides and maleated rosin-based dithioureas,were designed and synthesized.This research aims at providing a new way for deep processing and utilization of rosin.In this thesis,maleated rosin 1 was prepared using rosin as starting material,and converted into its acyl chloride 2,followed by hydrazinolysis of 2 to prepare maleated rosin hidrazide 3.Then,seven novel intermediates,maleated rosin-based dihydrazide 4a?4g,were prepared by reaction of 3 with substituted benzoyl chlorides,followed by cyclization of 4 with phosphorus oxychloride as catalyst to afford seven novel maleated rosin-based oxadiazole-amide compounds 5a?5g.Substituted benzoyl isothiocyanides were prepared using benzoyl chlorides as strarting materials,followed by reaction of maleated rosin hidrazide 3 with the isothiocyanides to obtain six novel maleated rosin-based dithiourea compounds 6a?6g.The synthetic conditions were investingated preliminarily and structures of the intermediates and the target compounds were characterized by means of IR,1HNMR,13CNMR,and MS.The herbicidal activity of intermediates maleated rosin-based dihydrazide 4,maleated rosin-based oxadiazole-amide compounds 5 and maleated rosin-based dithiourea compounds 6 was evaluated by barnyard grass beaker method and rape petri method.It was found that,at the concentration of 100 ?g·mL-1,the intermediates 4 and the maleated rosin-based oxadiazole-amide compounds 5 exhibited almost no growth inhibition activity agaist root of rape(Brassica campestris),and only part of the compounds 4 and 5 displayed weak growth inhibition activity agaist barnyard grass(Echinochloa crusgalli(L.)).Maleated rosin-based dithiourea compounds 6 exhibited a certain growth inhibition activity agaist root of rape,in which compound 6d(R=4-CH3O)had inhibition rate of 64.9%.All the compouds 6 showed no growth inhibition activity agaist barnyard grass.The fungicidal activity of the intermediates 4,the target compounds 5 and 6 against Physalospora piricola,Gibberella Zeae,Cercospora arachidicola,Alternaria solani,and Fusarium oxysporum f.cucumerinum was evaluate by the agar well diffusion method.It was found that,at the concentration of 50 ?g·mL-1,the intermediates 4,the target compounds 5 and 6 displayed a certain fungicidal activity against the above-mentioned fungi,expecially against Physalospora piricola,in which compound 4e(R=2-Cl)and compound 6c(R=4-CH3)had inhibition rates of 60.0%and 66.9%,respectively,against Physalospora piricola.The plant growth regulating activity of the intermediates 4 and the target compounds 5 and 6 was evaluated by wheat coleoptile section elongation method and cucumber cotyledon expansion method.The results showed that at the concentration of 10 ?g·mL-1,all the compounds exhibited a certain cytokinin and auxin activity in which compound 6f(R=4-Cl)had the best cytokinin activity of 22.0%while compound 6a(R=H)and 6b(R=3-CH3)had the best auxin activity of 18.4%.