Synthesis And Biological Activity Of Pinic Acid-based Dithiourea And Dithiadiazole Compounds

Turpentine is a natural and preponderant resource of China,and its main component is a-pinene.a-Pinene and its substructure units are good active groups.In recent years,it has become one of the research focuses for chemistry of organic synthesis and chemistry of fine chemicals to synthesize bioactive compounds through structural modification of a-pinene.In this thesis,a-pinene was converted into pinic acid at first,then,two types of novel pinic acid-based derivatives with bifunctional groups and potential biological activity,pinic acid-based dithioureas and pinic acid-based dithiadiazoles,were designed and synthesized by chemical modification of the carboxyl goups in pinic acid,and by introduction of active thiourea and thiadiazole groups into the skeleton of pinic acid.This research aims at providing a new pathway for high-value utilization of turpentine.In this thesis,pinic acid C was prepared via oxidation reaction and bromoform reaction using a-pinene as starting material,and converted into its dichloride D.Then,pinic acid-based diisothicyanate was prepared by reaction of pinic acid-based dichloride D with potassim thiocyanate,followed by reaction of pinic acid-based diisothiocyanate with substituted phenyl amines to afford twelve novel pinic acid-based dithiourea compouds E1?E12.Pinic acid-based diethyl esters D was prepared by esterfication of pinic acid C with ethanol.Then,pinic acid-based dihydrazide E was prepared by reaction of D with hydrazine hydrate,followed by reaction of E with substituted phenyl isothiocyanates to afford eight novel intermediates,pinic acid-based disubstituted phenyl acylamino thioureas F1?F8.Finaly,eignt novel pinic acid-based dithiadiazoles compounds G1?G8 were synthesized by cyclization of F1?F8 under catalysis of phosphoric acid.The synthetic conditions were investigated preliminarily.All the target compounds and the important intermediates were analyzed and characterized by means of FT-IR,13C-NMR,1H-NMR,MS,and elemental analysis.The herbicidal activity of pinic acid-based dithiourea compouds E1-E12,pinic acid-based disubstituted phenyl acylamino thioureas F1-F8,and pinic acid-based dithiadiazoles compounds G1?G8,was evaluated through rape petri method and barnyard grass beaker method.It was found that,at the concentration of 100 ?g·mL-1,most of the compounds E and G exhibited a certain growth inhibition activity against root of rape(Brassica campestris),in which compounds E1(R=H),G3(R=3-CH3)and G2(R=2-CH3)had inhibiton rates of 66.6%,68.3%and 72.3%,respectively.Also,only a few of the three types of compounds displayed weak growth inhibition activity against barnyard grass(Echinochloa crusgalli(L.)).The fungicidal activity of the compounds E,F,and G was evaluated by agar well diffusion method against Physalospora piricola,Alternaria solani,Fusarium oxysporum f.cucumerinum,Cercospora arachidicola,and Gibberella Zeae.It was found that,at the concentration of 50 ?g·mL-1,both compounds E and compounds F exhibited a certain inhibitory activity against Physalospora piricola,in which compound E3(R=3-CH3)and compound F7(R=4-Cl)had inhibition rates of 57.8%and74.7%,respectively.Compound E3(R=3-CH3)had the best inhibitory activity against Physalospora piricola,Alternaria solani,and Cercospora arachidicola.Compounds G displyed weak inhibitory activity against all the five tested fungi.The plant growth regulating activity of the compounds E,F,and G was evaluated by cucumber cotyledon expansion method and wheat coleoptile section elongation method.It was found that,at the concentration of 10 mg·L-1,most of the compounds exhibited a certain cytokinin and auxin activity,in which compounds E3(R=3-CH3)and G8(R=4-Br)had the best cytokinin activity of 19.2%(promotion)and-17.8%(inhibition),respectively,and compounds F8(R=4-Br)and E10(R=4-Br)had the best auxin activity of 17.6%(promotion)and-17.9%(inhibition),respectively.