Method for synthesizing a pymetrozine intermediate (oxadiazole ketone) by utilizing carbonate ester

Abstract

The invention discloses a method for synthesizing a pymetrozine intermediate (oxadiazole ketone) by utilizing carbonate ester. According to the method, hydrazine hydrate and an acetic acid ester are utilized as raw materials for hydrazine-ester condensation to synthesize acethydrazide; oxadiazole ketone is generated through a ring-closure reaction between acethydrazide and carbonate ester under certain conditions. Such environmental-friendly non-toxic or low-toxic dimethyl carbonate, diphenyl carbonate or dibenzyl carbonate 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; virulent phosgene and a great amount of inorganic solid hazardous waste are prevented from generating during a production process, so that major hidden dangers are reduced; the method has the advantages that the process 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 in particular relates to a method for synthesizing oxadiazolone, an intermediate of pymetrozine, with carbonate. 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 w...

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

[0014] In addition, a large amount of HCL is produced in all the above-mentioned phosgenation production processes. Generally, it is necessary to add a large amount of weak base such as sodium bicarbonate as an acid-binding agent to neutralize the reaction by-product HCL during the reaction process. Therefore, a large amount of HCL will be generated during the production process. Dangerous solid waste containing sodium chloride that is difficult to dispose of, or hazardous solid waste such as inorganic salts that are difficult to remove are likely to be generated during the treatment of phosgenation reaction tail gas. In addition to seriously polluting the environment, the salt generated in the tail gas degradation tower is often blocked Tower body or packing, causing tail gas degradation failure and causing safety accidents

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