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5-Methyl-1,3,4-oxadiazole-2(3H)-ones and preparing method thereof

A technology of oxadiazole and methyl, which is applied in the field of synthesis of agricultural pesticides, can solve the problems of large tail gas treatment capacity and high equipment requirements, and achieve the effects of low environmental pollution, easy availability of raw materials, and high product yield

Inactive Publication Date: 2007-08-08
YANCHENG SHUANGNING AGRI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the synthesis of this product is mainly based on the reaction of acetylhydrazide and phosgene. Its main patents are US5756752 and US4952701. The main defect of this method is that it uses gas phosgene, and it must have a separate phosgene generator, which requires high equipment. , a large amount of exhaust gas treatment

Method used

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  • 5-Methyl-1,3,4-oxadiazole-2(3H)-ones and preparing method thereof
  • 5-Methyl-1,3,4-oxadiazole-2(3H)-ones and preparing method thereof

Examples

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example 1

[0011] Example 1: Set up a stirrer, thermometer, dropping funnel and condenser in a 1000mL reaction flask, add 500mL1,2-dichloroethane and 30.8g bis(trichloromethyl)carbonate or chloromethyl trichloro Methyl ester, 1g of pyridine or 4-dimethylaminopyridine (DMAP), stir to dissolve, cool down to -10°C, add 40.2g of 92% strength acetylhydrazide and 100mL of 1,2-dichloroethane, drop into the bottle for 1 hour After the addition, the temperature was raised to 40° C. for 1 hour reaction, the reaction solution was concentrated, the solid was precipitated by freezing, and 28.6 g of the product was obtained by filtration, the content was 55%, and the yield was 31.5%.

example 2

[0012] Example 2: Set up a stirrer, thermometer, dropping funnel and condenser in a 1000mL reaction flask, add 500mL1,2-dichloroethane, 55.5g bis(trichloromethyl)carbonate or chloroformic acid trichloromethane ester, 1g of pyridine or 4-dimethylaminopyridine (DMAP), stirred and dissolved, cooled to 15°C, added 40.2g of 92% concentration of acetylhydrazide and 100mL of 1,2-dichloroethane, dropped into the bottle for 2 hours, added After completion, the temperature was raised to 60° C. to react for 6.5 hours, the reaction liquid was concentrated, the solid was precipitated by freezing, and 40.5 g of the product was obtained by filtration, the content was 94.5%, and the yield was 76.5%.

[0013] Example 3: Set up a stirrer, thermometer, dropping funnel and condenser in a 1000mL reaction flask, add 500mL1,2-dichloroethane, 75.7g bis(trichloromethyl)carbonate or chloromethyl trichloro Methyl ester, 1g of pyridine or 4-dimethylaminopyridine (DMAP), stirred and dissolved, cooled to 2...

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Abstract

The invention discloses a 5-methyl-1, 3, 4-oxadiazole-2 (3H)-ketone and making method, which is characterized by the following: looping acetydrazide and trichloromethyl chloroformate or di (trichloromethyl) carbonate to obtain the product; adopting pyridine or 4-dimethylamino pyridine as catalyst; using 1, 2-dichloroethane as dielectric solvent.

Description

technical field [0001] The invention relates to a synthesis method of agricultural pesticides, in particular to 5-methyl-1,3,4-oxadiazol-2(3H)-one and a preparation method thereof. Background technique [0002] Pymetrozine is a new type of heterocyclic insecticide in the triazinone class, which has the characteristics of high efficiency, low toxicity, high selectivity, and environmental friendliness. Pymetrozine has a high control effect on aphids, planthoppers, leafhoppers, whiteflies and stinkbugs in rice, vegetables, cotton, wheat, fruit trees and other crops. 5-methyl-1,3,4-oxadiazol-2(3H)-one is an intermediate of pymetrozine, and it is also an important pesticide and pharmaceutical intermediate. The English name is: 5-methyl-1, 3. 4-oxadiazol-2(3H)-one, cas registration number: 3069-67-8. At present, the synthesis of this product is mainly based on the reaction of acetylhydrazide and phosgene. Its main patents are US5756752 and US4952701. The main defect of this meth...

Claims

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Application Information

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IPC IPC(8): C07D271/07
Inventor 张保银段湘生冯成
Owner YANCHENG SHUANGNING AGRI CHEM
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