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A kind of preparation method of pymetrozine

A technology of pymetrozine and monochloroacetone, which is applied in the field of pesticide chemistry, can solve the problems of large amount of three wastes, low product purity, and many side reactions, and achieve reduced polymer generation, high yield and purity, and reduced by-products Effect

Active Publication Date: 2022-04-01
XINFA PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Although the above-mentioned synthetic route 2 adopts the method of condensation first and then neutralization, which is beneficial to reduce the decomposition and oxidation of free aminotriazone, it cannot fundamentally solve the drawbacks of synthetic route 1, such as long steps, cumbersome operation, and poor environmental protection.
[0013] In summary, in the prior art, the preparation method of pymetrozine has disadvantages such as many steps, cumbersome operation, large amount of three wastes, many side reactions, and low product purity. The synthetic route of pymetrozine, which is easy to realize, has few side reactions, high selectivity, high yield and high purity, is of great significance

Method used

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Experimental program
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Effect test

Embodiment 1

[0055] Embodiment 1: the preparation of carbohydrazide (Ⅲ)

[0056] In a 1000 ml four-neck flask connected with a stirring, thermometer, and reflux condenser, add 200 g of methanol, 200 g of water, and 90.1 g (1.0 mole) of dimethyl carbonate (II 1 ), 275.0 grams (2.2 moles) of 40% hydrazine hydrate, heated, stirred and reacted at 70 to 75°C for 3 hours, cooled to 20-25°C, filtered, the filter cake was washed with 20 grams of water, and dried to obtain 88.7 grams of carbohydrazide (Ⅲ), the yield is 98.5%, and the liquid phase purity is 99.9%.

Embodiment 2

[0057] Embodiment 2: the preparation of carbohydrazide (Ⅲ)

[0058] Into the 1000 ml four-neck flask connected with stirring, thermometer and reflux condenser, add 200 g of ethanol, 200 g of water, 118.1 g (1.0 mole) of diethyl carbonate (II 2 ), 275.0 grams (2.2 moles) of 40% hydrazine hydrate, heated, stirred and reacted at 75 to 80°C for 2 hours, cooled to 20-25°C, filtered, the filter cake was washed with 20 grams of water, and dried to obtain 88.9 grams of carbohydrazide (Ⅲ), the yield is 98.8%, and the liquid phase purity is 99.9%.

Embodiment 3

[0059] Embodiment 3: Preparation of pyridin-3-yl methylene carbohydrazide (IV)

[0060] In the 1000 milliliter four-neck flask that is connected with stirring, thermometer, constant pressure dropping funnel and reflux condenser, add 200 grams of methyl alcohol, 100 grams of water, 45.0 grams (0.5 mole) carbohydrazide (Ⅲ) obtained in embodiment 1 , heated, kept between 55 and 60°C, added dropwise a mixed solution of 53.0 grams (0.5 moles) of 3-formylpyridine and 100 grams of methanol, and the addition was completed in 3 hours, then stirred and reacted at 60 to 65°C for 6 hours, and cooled to 20-25°C, filter, wash the filter cake with 30 g of water, and dry to obtain 88.8 g of pyridin-3-ylmethylenecarbohydrazide (IV), with a yield of 99.2% and a liquid phase purity of 99.9%.

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Abstract

The invention provides a method for preparing pymetrozine, which uses carbonic acid diester and hydrazine hydrate to prepare carbohydrazide through hydrazide reaction, and the obtained carbohydrazide and 3-formylpyridine undergo condensation reaction to prepare pyridine-3 - Base methylene carbohydrazide, and finally prepare pymetrozine through cyclization reaction with monochloroacetone. The raw materials of the method of the invention are cheap and easy to obtain, and the cost is low; the process flow is short, and pymetrozine can be prepared in only three steps; the operation is safe and simple, and the reaction conditions are easy to realize; The product has high stability, high reaction selectivity, less side reactions, high yield and purity of the target product, and is beneficial to the industrial production of pymetrozine.

Description

technical field [0001] The invention relates to a preparation method of pymetrozine, which belongs to the technical field of pesticide chemistry. Background technique [0002] Pymetrozine (I), the English name is Pymetrozine, the CAS number is 123312-89-0, the chemical name is 4,5-dihydro-6-methyl-4-(3-pyridinemethyleneamino)-1, 2,4-triazin-(2H)-one, its structural formula is as follows: [0003] [0004] Pymetrozine is a new type of iminopyridine insecticide developed by Ciba-Geigy in 1988. It belongs to triazinone insecticide and is a new non-biocide Insecticide, exhibits excellent control effect on piercing-sucking mouthparts pests of various crops. Studies have shown that whether pymetrozine is tested by drip, feeding or injection, as long as aphids or planthoppers come into contact with pymetrozine, they will immediately block the stylet, stop feeding, and eventually starve to death, and this process is irreversible. Pymetrozine has a wide insecticidal spectrum an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D401/12
CPCC07D401/12
Inventor 江枭南周立山戚聿新
Owner XINFA PHARMA
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