Stereoselective Activation Of Aromatic Nitrogen Atoms And Selective Modification Of Pesticide Active Molecule

The high-quality development of agriculture is always related to the livelihood of the people,national development,and social stability,and has been highly valued and recognized by many countries and researchers around the world.Pest and disease threats have always been one of the major factors affecting agricultural production and safety in China.Currently,one of the most effective ways to control pests and diseases is through the scientific and rational use of organic green pesticides.However,the production and use of ordinary organic pesticides face many problems,such as residual chemicals,resistance,and re-emergence,which pose a serious threat to human living environments,production,and life while dealing with pest and disease control.Therefore,creating green,efficient,and low-risk organic pesticide molecules is currently a hot topic in many studies.Furthermore,chiral pesticides with a single configuration can reduce dosage and increase efficacy,and many drug molecules,including some pesticide molecules,belong to aromatic heterocyclic compounds.Therefore,it is of great research significance to construct a series of novel structurally and potentially biologically active chiral aromatic heterocyclic compounds through efficient and concise synthetic methods using organic small molecule catalysts such as N-heterocyclic carbenes(NHC).Through subsequent bioactivity testing,target compounds with good bioactivity can be screened,laying the experimental foundation and providing theoretical guidance for further research.In addition,a herbicidal pesticide molecule with herbicidal activity was selectively modified by the chemical hydroxylation of α-methyl glucoside at different sites through the regulation of boronic acid and the catalytic activation of nitrogen heterocyclic carbene,aiming to solve the problems of metabolic toxicity and compound solubility in plants using the physicochemical properties of sugar compounds.The main research contents of this thesis are summarized as follows.1.Under the activation of N-heterocyclic carbene as small organic molecule catalysts,using indole(or pyrrole)-2-aldehyde as the starting material,and reacting with reactive ketones such as Isatin,α-ketoester,a series of chiral spiro-cyclic indole N,Oacetals products with excellent yield and stereoselectivity and novel structures were constructed.These products have similar active skeletons to indole alkaloids such as sclerotiamide,and several target compounds such as II-104-3a,II-104-3c,II-104-3h,II-104-3i,II-104-3j,II-104-4a,II-104-4b,II-106-9a,II-106-9e,and II-106-9g showed good inhibitory activity against Ralstonia solanacearum(Rs)at test concentrations of 100 μg/m L and 50 μg/m L,which were better than the commercial drugs such as Thiediazole copper and Bismerthiazol.When tested at concentrations of100 μg/m L and 50 μg/m L,compounds II-104-3b,II-104-3c,II-104-3d,II-104-3e,II-104-3f,II-104-3g,II-104-4a,II-104-4b,II-104-4q,and II-106-9f showed good inhibitory activity against Xanthomonas oryzae,(Xoo),and were superior to the commercial drug,Thiediazole copper.Their inhibitory effect was also better than that of the Bismerthiazol,at a test concentration of 100 μg/mL.However,these compounds showed almost no inhibitory effect against Colletotrichum(Cc)and Phycomycetes(Pc),and their test results were much worse than those of the commercial reference drugs,prochloraz-manganese chloride complex and dimethomorph.Chiral N,O-acetals also possess a similar skeleton to the insecticide spirotetramat in comparison to which we tested the insecticidal activity of the target compounds.At a testing concentration of200 μg/m L,compounds II-104-4d and II-104-4h exhibited 70% insecticidal activity against the the Plutella xylostella(Linnaeus).However,their efficacy was still inferior to that of commercial pesticides such as Chlorpyrifos and Avermectin.2.We used commercially available herbicide molecules such as dicamba,clopyralid,and 2,3,5-trichlorobenzoic acid as starting active lead substrates and siteselectively modified the multi-hydroxyl group of α-methyl glucoside under the regulation of boronic acid and N-heterocyclic carbene catalysis.The modification of2,3,5-trichlorobenzoic acid resulted in glycosylation products with C2-OH and C3-OH,while clopyralid and dicamba resulted in single C3-OH glycosylation products with moderate yields.We isolated and tested different glycosylation products for their herbicidal activity.At a testing concentration of 10 mmol/L,compared with the blank CK,modified products Ⅳ-13,Ⅳ-14 of 2,3,5-trichlorobenzoic acid,Ⅳ-15 of clopyralid,and Ⅳ-16 of dicamba all showed varying degrees of growth inhibition against broadleaf weeds such as Amaranthus retroflexus L,with Ⅳ-13,Ⅳ-14,and Ⅳ-15 being comparable to the commercial products.However,the weed control effect of Ⅳ-16 after glucose modification of the commercial control drug dicamba was far inferior.No significant growth inhibition effect was observed for Ⅳ-13,Ⅳ-14,Ⅳ-15,and Ⅳ-16 on broadleaf weed Abutilon theophrasti Medicus at a testing concentration of 10mmol/L.