Study On Synthesis And Herbicidal Activity Of Sulfate Oxime Esters

Weeds are not only the risk to agricultural production, but also affect many other sectors of national production. Chemical weeds control has been proved to be efficient and labor saving. Therefore, using the measure of chemical weeds control, instead of manual weeding, is the urgent need and inevitable trend of agricultural mechanization and modernization. As a result, the development of new herbicides is a hot topic in the field of pesticides research. And efficiency, safety and economical will be the goal of new herbicides development in the 21st century.Sulfate acid derivatives and oxime compounds both have excellent herbicidal activity. Furthermore, many varieties have the features of high efficiency, low toxicity and low residue. Currently, the reported research on the herbicidal activity of oxime esters were mostly carbonate oxime esters and phosphate oxime esters. There were no report on sulfate oxime esters. Therefore, this paper attempted to synthesis a series of sulfate oxime esters, and research the herbicidal activity of these compounds.The major work of this paper as follows:1.15 varieties of intermediate product oxime compounds were synthesized. And the reaction conditions of oximes were optimumed. Reaction conditions:the aldehyde(or ketone) and hydroxylamine hydrochloride as the raw material, water and anhydrous ethanol as solvent, sodium hydroxide as HC1 scavenger, reacted at 10℃-15℃for 2 h-5 h. Solid products could precipitated, filtrated, recrystalled with petroleum ether (60-90), we got the products. Liquid products were extracted with ethyl acetate, dried by anhydrous MgSO4, distilled out the solvent,then we got the product. The yield of oximes were within the limit of 40%-88%.2.17 varieties of sulfate oxime esters were synthesized. And the reaction conditions of target products sulfate oxime esters were optimumed. Reaction conditions:the aldehyde oximes (or ketone oximes) and sulfuric chloride as the raw material, chloroform as solvent, reacted at 40℃-60℃for 3 h-9.5 h. After the reaction solution was cooled to room temperature, it was washed by hydrochloric acid or sodium bicarbonate, dried by anhydrous MgSO4, distilled out the solvent, then we got the crude products. The crude products were purified by methods of column chromatography or recrystallization. The yield of sulfate oxime esters were within the limit of 2%-35%.3.The paper analyzed the physical properties of the intermediate products and the target products, such as melting point and solubility. And the structures of some compounds were characterized by modern analytical methods of IR, MS and 1HNMR.4.In this paper we choosed Echinochloa beauvois and Oryza sativa as the representation of the Monocots, Brassica chinensis and Amaranthus ascendens Loisel as the representation of the dicotyledons to study the herbicidal activity of the 17 sulfate oxime esters.The results showed that the herbicidal activity was affected by different structures and concentration of novel compounds and the plants'species.Compounds sulfate di-4-nitrobenzaldoxime ester and sulfate di-3-nitrobenzaldoxime ester had notable inhibition to Echinochloa beauvois in the aspects of survival rate, weight-growth, stem-growth and root-growth. And compound sulfate di-4-Chlorobenzaldehydoxime ester had notable inhibition to Echinochloa beauvois, when at the concentration of 100 mg/L, the Echinochloa beauvois's correction stem-growth and correction root-growth were all lower than -20%.Compounds sulfate dibenzaldoxime ester, sulfate di-2-Chlorobenzaldehydoxime ester and sulfate di-4-nitrobenzaldoxime ester had notable inhibition to Oryza sativa in the aspects of weight-growth and root-growth. Especially compound sulfate di-4-nitrobenzaldoxime ester had highly significant inhibition to Oryza sativa, when at the concentration of 400 mg/L, the Oryza sativa's weight-growth was -49.0%.All compounds tested had notable inhibition to Brassica chinensis in the aspects of survival rate, weight-growth and root-growth. Especially compound sulfate difuraldoxime ester at the concentration of 400 mg/L, the Brassica chinensis's survival rate was -86.7%. And the inhibition of the novel compounds to Brassica chinensis was better in the aspect of root-growth than stem-growth.All compounds tested had notable inhibition to Amaranthus ascendens Loisel in the aspects of survival rate, weight-growth, stem-growth and root-growth. All compounds at the concentration of 400 mg/L, the Amaranthus ascendens Loisel's survival rate were-90.0%. And the inhibition of the novel compounds to Amaranthus ascendens Loisel was better in the aspect of root-growth than stem-growth.From the herbicidal activity test results, we presumed that there is a chance to find a herbicide with commercial value by modifying or change the substituents of sulfate oxime esters.This paper had preliminary studied on the herbicidal activity of sulfate oxime esters, and done useful works for the discovery of the leading compounds of novel herbicides.