Studies On Synthesis And Herbicidal Activity Of Novel Pyridine Condensed Heterocyclic Derivates

Due to the structres of pyridine condensed heterocyclic derivates displayextensive biological and pharmacological activity,such as, herbicide, insecticide,antibacterial analgesic,analgesic, antipyretic,antimalarial agent,and so on, therefore,Studying on polycyclic pyridine takes an important signification not only in human’shealthy but also in pesticides fields. In this paper, Based on our group previousexperiment,using obviously herbicidal and fungicidal pyridine ring designed andsynthesized diversiform heterocyclic compounds. we mainly to probe and find moreeffective method to synthesize pyrido[4,3-d]pyrimidine;pyrido[4,3-d][1,3]oxazine;pyrido[4,3-d]-1,2,4-triazolo[5,1-f]-Pyrimidine.In this dissertation, we also modified and reformed their constructions. Bychanging different substituent groups to compare their herbicidal activities. We wantto find the relationship between their substituent groups and herbicidal activities. soas to acquire some good herbicides with high activity low toxicity and friendly to theenvironment. In this paper, about sixty unreported compounds were synthesized andconfirmed by¹H NMR、¹³C NMR、HRMS and X-ray crystal structure diffraction.Itmay be summarized as follows:1. Pyridine condensed heterocyclic derivates in four series were synthesized byusing aza-wittig reaction and methods recrystallization was used to separate andpurify the chemical constituents.those compounds are summarizaed as follow:I:2-substituted aromatic-8-methyl-10-substituted alkyl-7-[N-substitutedaromaticacyl-ethyl hydrazone] pyrido[4,3-d]-1,2,4-triazolo[5,1-f]pyrimidinederivatives.（26）II:2-substituted amino-4-methylene-5-methyl-7-alkylthio-8–nitrile-4-H-pyrido-[4,3-d][1,3] oxazine derivatives （20）III:2-substituted amino-4-methylene-5-methyl-7–sulfone/methoxy–8–nitrile-4-H-pyrido [4,3-d][1,3] oxazine derivatives （14）2. The prediminary herbicidal activity of the new compounds mentioned weremeasured, according to the experiment, some compounds possessed high herbicidalactivity have been found.