Study On The Synthesis And Herbicidal Activity Of Di-N-Oxide Quinoxaline Formaldehyde-Alkyloxyl Aminophosporylhydrazone

There are more than 1, 800 kinds of weeds which endanger the crops in the world. It makes serious economic losses on annual agricultural production. Chemical herbicides present a drastic protection to farming, but the phytocidal efficiency and security cannot meet the demand of modern agricultural production and development yet. So, research and exploiture on new herbicides has become a hot topic since the last over half century.Quinoxaline di-N-oxides compounds were firstly reported as ones of the nitrogen-containing fused heterocyclic with anti-bacterial and anti-cancer activity, and then used as feed addition. Recently our group found that formaldehyde derivatives of quinoxaline di-N-oxides compounds have obvious herbicidal activity. In this study, sub-structure phosphate groups with herbicidal activity were introduced to quinoxaline di-N-oxides compounds and the herbicidal activity has also been investigated which will offer important reference for the further research of the relationship between the structure and the herbicidal activity of such compounds. On the basis of our earlier researches, this paper accomplished the works as follows:1. Synthesize the intermediate di-N-oxide quinoxaline formaldehyde: Benzofura zane(Intermediateâ… )was synthesized with o-nitro aniline; followed by reacting with acetone to produce the methyl di-N-oxide quinoxaline(Intermediateâ…¡); at last the product was oxidized by selenium dioxide to form the di-N-oxide quinoxaline formaldehyde(Intermediateâ…¢). The yield of the Intermediatesâ…¢was about 32%. The chemical equation as follows: 2. Synthesize 20 kinds of alkyloxylaminophosphorylhydrazide(Intermediatesâ…¥a-t): Alkyloxylphosphorodichloridate(Intermediatesâ…£) are stepwise synthesized using phosphorus oxychloride and alcohol or phenol; followed by reacting with aromatic amines to produce the alkyloxylaminophosphoruschloride(Intermediatesâ…¤); alkyloxylaminophosphorylhydrazide are synthesized by the reaction Intermediatesâ…¤and hydrazine hydrate. The chemical equation was as follows:The yield of the intermediateâ…¥was in the range of 10% -70%.3.Di-N-oxide quinoxaline formaldehyde-alkoxylaminophosporylhydrazone(In termediatesâ…¦a-t) are synthesized using the di-N-oxide quinoxaline formaldehyde (Intermediateâ…¢) and alkyloxylaminophosphorylhydrazide(Intermediatesâ…¥).The chemical equation was as follows:The yield of the intermediateâ…¦was in the range of 20%⁷0%.4.The reaction conditions which involved withâ…£toâ…¦were discussed and some reaction conditions are optimized in the research. And the structure of some final products were characterized by IR and ¹H NMR.5.Monocotyledon Echinochloa Beauvois and dicotyledon Wild amaranth were selected as biomarker and were used in the herbicide produces acetochlor according to the reference. Herbicidal activity study of the 20 final products with four different mass concentrations of 200 mg/L, 350 mg/L, 400 mg/L and 800 mg/L was also carried out.The results showed that the herbicidal activity changes through the difference of species and concentrations of novel compounds. The KR(Killing Rate) of new compounds VIId(R₁=Et,CE₃),â…¦g(n-Bu,CH₃) to Echinochloa Beauvois had beyond 40%, when their mass concentration were 800 mg/L, most of new compounds had no killing effects on the Wild amaranth, except compoundsâ…¦b(n-Pr,H),â…¦f(Ph,H),â…¦l(n-C₅H₁₁,H),â…¦m(n-C₅H₁₁,CH₃),â…¦o(n-C₆H₁₃,H),â…¦p(n-C₆H₁₃,CH₃) whose KR are lower 10%; the herbicidal activity of novel compounds to monocotyledon Echinochloa Beauvois was better than to dicotyledon Wild amaranth; the inhibion rate of the new compounds was weaker than the acetochlor to the Monocotyledon and dicotyledon.This thesis makes great proofs for the synthesis and herbicidal activity study of di-N-oxide quinoxaline formaldehyde derivatives.