Preparation method of carbofuran derivatives

Abstract

The invention discloses a preparation method of carbofuran derivatives. The preparation method of the carbofuran derivatives comprises the following steps: (1) taking amine derivatives and sulfur monochloride as raw materials, adding a first acid-binding agent and a reaction solvent and performing sulfuration reaction to obtain a first intermediate disulfide, wherein the first acid-binding agent is triethylamine and the reaction solvent is chloroform or dichloromethane; (2) performing chlorination reaction on the first intermediate disulfide and chlorine which serve as raw materials to obtain a second intermediate nitrogen and sulfur chloride; (3) taking the second intermediate nitrogen and sulfur chloride and carbofuran as raw materials, adding a second acid-binding agent and performing condensation reaction to obtain the carbofuran derivatives. The preparation method has the advantages that the process is simple, and the product is low in toxicity, high in purity and high in yield.

Description

technical field [0001] The invention belongs to the technical field of pesticide preparation, and in particular relates to a preparation method of carbofuran derivatives. Background technique [0002] Carbofuran is a broad-spectrum insecticide and nematocide with contact and stomach poisoning effects. It is suitable for the control of various pests on rice, cotton, tobacco, soybean and other crops, and can also be used as a seed treatment agent. With the growing calls for low-toxicity pesticides, the ban on the highly toxic carbofuran has also entered the countdown, and the low-toxicity carbofuran derivatives are very important carbamate insecticides, and the main varieties include butylsulfonate Budweiser and carbosulfan have strong insecticidal properties, fast-acting, short residual period, strong selectivity and low toxicity to higher plants, and their toxicity is only one-twentieth of that of carbofuran (Zeng Xianze et al. "Chemical Synthesis of Carbofuran", "Pesticide...

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Problems solved by technology

In the patent US4329293A, n-hexane is used as the reaction solvent, and triethylamine is used as an acid-binding agent to obtain 95% carbosulfan crude oil, but there are safety risks in n-hexane as a solvent

Chinese patent CN00113443.4 can obtain carbosulfan crude oil with a content of 92% by column chromatography, but has the disadvantages of high purification cost and low content

Chinese patent CN102786503A uses cosolvent N-methylpyrrolidone or dimethylformamide to improve the solubility of carbofuran in the reaction solution, and the yield of the target compound carbofuran is 97% (calculated as carbofuran) , with a content of 96%, but it needs to add a co-solvent, which makes it difficult to recycle and lose, the trouble of post-processing and the difficulty of wastewater treatment

[0004] Among these patents, the Chinese patent CN102786503A utilizes co-solvent N-methylpyrrolidone or dimethylformamide to improve the solubility of carbofuran in the reaction solution, with a yield of 97% (calculated as carbofuran) and a content of 96%. %, but it needs to add a co-solvent, which leads to the loss of recycling, the trouble of post-processing and the difficulty of wastewater treatment

In other synthetic methods, because the solubility of triethylamine hydrochloride in conventional solvents is very small, carbofuran is partially wrapped by triethylamine hydrochloride during the condensation reaction, causing part of carbofuran to fail to participate in the reaction. As a result, the content and yield of carbofuran derivatives with low toxicity are not high, which seriously hinders the popularization and application of carbofuran derivatives such as carbosulfan and carbosulfan

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