Synthesis And Herbicidal Activity Of Pyrazole Acyl Amino Acid Ester Derivatives

The emergence and development of chemical herbicides, which greatly enhanced production of agricultural production and increased efficiency of agricultural production. Efficient, safe and economical herbicides is the development direction of the 21st century. Pyrazole and the amino acid ester compounds themselves have strongly biological activity, widely used in research and development of new herbicides. In order to explore new herbicides wich have higher activity, we select a higher biological activity of pyrazole-based sub-structure, amino acid ester groups to amide bond as a link, designed and synthesized a series of pyrazole amino acid ester derivatives according to the principle of combination of bioactive substructure. The target products were characterized by IR, MS,1HNMR. The herbicidal activity tests of the target compounds were also investigated.I The Preparation of 4-chloro-3-ethyl-1-methyl-5-pyrazolyl chlorideStart with diethyl oxalate and 2-butanone to get propionyl pyruvate by the claisen condensation reaction. Then, pyrazole carboxylic acid ethyl ester was readily synthesized via Knorr condensation of hydrazine hydrate with propionyl pyruvate, Next the pyrazole 1-bits methylation,4-bits halide, hydrolysis pyrazole carboxylic acid, and thionyl chloride acylating get their 4-chloro-3-ethyl-1-methyl-5-pyrazole chloride. We discussed this synthesis and worked out better synthesis conditions.II Preparation of amino acid ester hydrochlorideAt first, in ice and salt bath, thionyl chloride was added into methanol solution. A series of amino acid ester hydrochloride were prepared from amino acid and this reaction solution.The synthesis reaction conditions were mild, easy to operate, easy to purify the product with high yield and purity.ⅢPreparation of pyrazole acyl amino acid estersIn dichloromethane, useing triethylamine to bind acid, the first low-temperature reaction of 4h, then at room temperature for 5h, ten compounds of acyl amino acid ester derivatives of pyrazole were prepared from pyrazole chloride and different substituted amino acid ester hydrochloride salt. The pyrazole acid radical amino-acid ester in the ether solution, joins the catalyzed quantity the water, under the sodium hydroxide function the hydrolisis, obtains the pyrazole acid radical amino acid compound.ⅣThe antioxidant activity testReference to "pesticide testing guidelines for herbicides in indoor test", using plate method, select the monocots rice and Sorghum as tested crops, oilseed rape and white dicotyledon Amaranthus as test crop, set the concentration gradient of 200 mg/L,100 mg/L,60 mg/L, We have carried on the weeding biological activity test to the new synthesis’s 14 kind of goal compound, discussed this kind of compound to the plant growth active influence. The results showed that:in the experiment range, some of the compounds have good herbicidal activity.