Method for synthesizing pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester

A technology of haloformic acid ester and oxadiazolone, which is applied in the field of preparation of oxadiazolone, an intermediate of high-efficiency insecticide pymetrozine, can solve the problems of tail gas degradation failure, mass casualties, and highly toxic phosgene to reduce major safety hazards, the reaction conditions are mild and easy to control, and the process is safe and reliable.

Active Publication Date: 2015-07-29
兰州鑫隆泰生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Now triphosgene is generally used as a substitute raw material for phosgene and diphosgene in industrial production. Although the reaction is relatively mild, it may still decompose and produce highly toxic phosgene during the feeding and dissolving operation and the reaction process. There is a greater safety hazard. There are also many major safety accidents in China that caused mass casualties due to improper disposal and out-of-control reactions in the production process of solid phosgene
[0012] In addition, a large amount of inorganic salts are likely to be produced in the tail gas treatment process of all the above-mentioned phosgenation reactions. In addition to seriously polluting the environment, the salt generated in the tail gas degradation tower often blocks the tower body or packing, resulting in failure of tail gas degradation and safety accidents

Method used

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  • Method for synthesizing pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester
  • Method for synthesizing pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester
  • Method for synthesizing pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester

Examples

Experimental program
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Effect test

Embodiment 1

[0044]In the oxadiazolone 500ml reaction bottle, install agitator, thermometer, constant pressure dropping funnel and condenser, and all instruments will be dry and anhydrous. At room temperature, add 300ml of solvent 1,2-dichloroethane, 37.0g of acetylhydrazine, 46.5g of acid-binding agent sodium bicarbonate, start stirring, cool down, control the reaction temperature to about -10°C, and slowly add 52.0g of chloroformic acid dropwise 100ml dichloroethane solution of methyl ester, keep warm for 1.5hr after feeding, heat slowly to 30°C-35°C for 0.5h after reaction is stable, slowly heat up to reflux, reflux keep warm for 6-7 hours, take samples Analysis, when the residual acetylhydrazine ≤ 1.0%, the reaction is basically over, and the temperature is properly lowered to 25-50 °C, and 20.0 g of the catalyst 30% sodium methoxide solution is added under a slight negative pressure, and the temperature is slowly raised to reflux for 6.0 hours. The continuous removal of product promot...

Embodiment 2

[0046] In the oxadiazolone 500ml reaction bottle, install agitator, thermometer, constant pressure dropping funnel and condenser, and all instruments will be dry and anhydrous. At room temperature, add 250ml of solvent toluene and 37.0g of acetylhydrazide, start stirring, cool down, control the reaction temperature from -15°C to 50°C, slowly add 50.0g of methyl chloroformate in 100ml of toluene solution dropwise, and keep warm for reaction after the addition is complete 4.0hr, after the reaction is stable, heat slowly to 30°C-60°C and keep it warm for 1.5 hours, then slowly heat up to reflux, keep it under reflux for 12 hours, take a sample for analysis, when the residual acetylhydrazine ≤ 1.0%, the reaction is basically over, and the temperature should be lowered appropriately Add catalyst 30% sodium methoxide solution 20.0-40.0g under slight negative pressure at 25-50°C, check the pH of the reaction solution, slowly raise the temperature to reflux and keep it warm for 8.0 hou...

Embodiment 3

[0048] In the oxadiazolone 1000ml reaction bottle, install agitator, thermometer, constant pressure dropping funnel and condenser, and all instruments will be dry and anhydrous. At room temperature, add 500ml of solvent chloroform, 74.0g of acetylhydrazide, 60.0g of acid-binding agent sodium carbonate and 27.5g of sodium methoxide, start stirring, cool down, control the reaction temperature -20°C-20°C, and slowly add 108.3g dropwise 200ml chloroform solution of methyl chloroformate, keep warm for 3.0hr after feeding, heat slowly to 25°C-35°C for 1.5 hours after the reaction is stable, slowly heat up to reflux, keep warm at reflux for 3 hours, take samples for analysis , when the residue of acetylhydrazine ≤ 1.0%, the reaction is basically over, filter and wash while it is hot to remove inorganic salts, collect the filtrate and transfer it to another 1000ml reaction bottle of the same device, stir, cool down to room temperature, and add 18.5g of catalyst phosphorus pentoxide an...

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Abstract

The invention discloses a method for synthesizing a pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester. According to the method, oxadiazole ketone is generated through a ring-closure reaction between acethydrazide and halogenated formate ester under certain conditions. Phosgene, diphosgene or triphosgene which can easily trigger group safety accidents is prevented from being utilized as a process route for the ring-closure reaction; such halogenated formate ester as phenyl chloroformate or phenyl chloroformate is utilized for replacing previously common virulent phosgene, diphosgene or triphosgene as a carbonylation ring-closure reagent; under the action of catalysts, a ring-closure cyclization reaction is performed for preparation of oxadiazole ketone; generation of virulent phosgene during a production process is avoided, so that major hidden dangers are reduced; the method has the advantages that technology is safe and reliable, reaction conditions are mild and easy to control, after-treatment is convenient, and an environmental-friendly effect is achieved.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis of pesticides, and relates to a preparation method of oxadiazolone, an intermediate of high-efficiency insecticide pymetrozine. Background technique [0002] Pymetrozine belongs to pyridine or triazinone insecticides. It is a brand-new non-biocide insecticide. It was first developed by Ciba-Geigy in Switzerland in 1988. Pests showed excellent control effect. Studies using electropenetration graph (EPG) technology have shown that no matter in drip, feeding or injection experiments, as long as aphids or planthoppers come into contact with pymetrozine, they will immediately produce a stylet blocking effect, stop feeding immediately, and eventually starve to death , and this process is irreversible. Pyridoxone has no knockdown activity and does not produce direct toxicity to insects. Therefore, pymetrozine has an excellent function of blocking insect transmission. Pymetrozine has a wide ...

Claims

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Application Information

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IPC IPC(8): C07D271/113
CPCC07D271/113
Inventor 欧阳建峰黄朝纲李明孙静丽孙衍辉雷晓峰
Owner 兰州鑫隆泰生物科技有限公司
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