Method for synthesizing diflubenzuron by one-pot method

Abstract

The invention relates to a method for synthesizing diflubenzuron through a one-pot method, and belongs to the technical field of pesticides. The preparation method comprises the following steps: enabling reaction between parachloroaniline as a raw material and triphosgene under the catalysis of a catalyst to synthesize 4-chlorphenyl isocyanate; and directly reacting with 2, 6-difluorobenzamide to generate the diflubenzuron without purification. The catalyst adopted by the invention effectively promotes synthesis of parachloroaniline isocyanate and inhibits the generation of impurities. The generated isocyanate intermediate does not need to be separated and purified and can be directly synthesized in the next step, so that the risk of degradation of the isocyanate intermediate is reduced while the separation and purification process is omitted. The method has the advantages of simple process, few side reactions, high product quality, high yield, safe and environment-friendly operation and the like, and provides good conditions for industrial production.

Description

technical field [0001] The invention belongs to the technical field of pesticides, and in particular relates to a method for synthesizing diflubenzuron in one pot. Background technique [0002] Diflubenzuron belongs to the class of diflubenzuron insecticides. It is an insect growth regulator discovered in the 1970s. Its main function is to inhibit the synthesis of chitin in the epidermis of insects, and at the same time, it has the effect on endocrine and glands such as fat body and pharyngeal body. The body also has the effect of damaging and destroying, so that the insects cannot molt normally and die due to deformity. It is a low-toxic and pollution-free pesticide. Mainly used to control Lepidoptera pests, such as cabbage caterpillar, diamondback moth, beet armyworm, spodoptera litura, golden leaf miner, peach line leaf miner, citrus leaf miner, armyworm, tea looper, cotton bollworm, American White moth, pine caterpillar, leaf roller moth, leaf roller etc. Can be widely...

AI Technical Summary

Problems solved by technology

The esterification of 2,6-difluorobenzamide in method 1 generally uses oxalyl chloride as an esterification reagent (phosgene and triphosgene have poor reaction effects and almost no reaction), which is expensive, and storage and transportation conditions are harsh, and industrial production High difficulty

In Method 2, solid phosgene can be used as the esterification reagent for the esterification of p-chloroaniline. Although triphosgene has advantages in terms of cost and storage, the esterification of p-chloroaniline in the currently reported synthesis schemes will produce white Insoluble impurities need to be removed by filtration, the yield of esterification reaction is low, the cost of filtration equipment is high, and the filtration process will have a great impact on the environment due to the strong taste of isocyanate itself and the residual triphosgene in the reaction

At the same time, p-chlorophenyl isocyanate is extremely afraid of water, decomposes with water, and has a low melting point (26-29° C.). It will partially decompose in the process of separating from the solvent, which will affect the yield and quality, thereby affecting the synthesis cost of diflubenzuron. Therefore Looking for a catalyst to promote the synthesis of isocyanate while inhibiting the formation of impurities. If the intermediate isocyanate can be directly carried out in the next step without discharging the one-pot method, it will have a high cost advantage and industrialization prospects

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