Preparation method of difenoconazole

Abstract

The invention relates to a preparation method of difenoconazole, comprising the steps of: (1) in the presence of aluminium trichloride, subjecting 3, 4'-dichloro diphenyl ether and chloroacetyl chloride to a Friedel-Crafts reaction so as to generate chlorobenzene ether ketone; (2) in the presence of a catalyst, conducting a cyclisation reaction to chlorobenzene ether ketone and 1, 2-propylene glycol, thus obtaining cis, trans-3-chlorine-4-(4-methyl-2-chloromethyl-1, 3-dioxolane-2-yl) phenyl-4'-chlorophenyl ether; (3) in the presence of sulfolane, carrying out a condensation reaction at a temperature of 190-230DEG C to cis, trans-3-chlorine-4-(4-methyl-2-chloromethyl-1, 3-dioxolane-2-yl) phenyl-4'-chlorophenyl ether and 1, 2, 4-triazole, thus obtaining cis, trans-3-chlorine-4-[4-methyl-2-1H-1, 2, 4-triazole-1-ylmethyl]-1, 3-dioxapentane-2-yl) phenyl 4-chlorophenyl ether, then performing filtration and exsolution when the reaction is over, thus obtaining a crude product of difenoconazole; (4) implementing rectification to the crude product, then carrying out crystallization with a solvent and performing centrifugation, thus obtaining the product of difenoconazole. The method provided in the invention has the advantages of short production period, low production cost and good production security.

Description

technical field [0001] The invention relates to a preparation method of difenoconazole. Background technique [0002] Difenoconazole (chemical name: cis, trans-3-chloro-4-[4-methyl-2-1H-1,2,4-triazol-1-ylmethyl)-1,3-di Dummy pentane-2-yl)phenyl 4-chlorophenyl ether) is a new type of triazole systemic broad-spectrum fungicide, low toxicity and high efficiency, unique crop safety, and can form with a variety of pesticide products Compound preparations are increasingly used in industrial and agricultural production. The traditional process at home and abroad uses 3,4'-dichlorodiphenyl ether as raw material, first reacts with acetyl chloride to obtain 4-(4-chlorophenoxy)-2-chloroacetophenone, and then undergoes cyclization and condensation , refined to obtain the finished product, its process route is as follows: [0003] [0004] The above-mentioned route is the traditional route of domestic and foreign manufacturers, in which there is a one-step bromination reaction, and...

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Problems solved by technology

[0004] The above-mentioned route is the traditional route of domestic and foreign manufacturers, in which there is a one-step bromination reaction, and its by-product is hydrobromic acid, which is a highly toxic product, and liquid bromine is also a major hazard source, and strict protection is required in production operations. Bromine is getting more expensive, accounting for an increasing proportion of the cost of difenoconazole

Moreover, because the cyclized compound is not stable enough, it is easy to undergo a reversible reaction during bromination, resulting in a low conversion rate of the bromination reaction and a low bromide content.

In the traditional route, because the solvent is mostly DMSO or DMF, the condensation temperature is difficult to increase, so the condensation time is longer, and the average isomer content is more than 13%, which is difficult to completely remove during refining, resulting in low product content. high

Most of the multi-component solvents are used in crystallization, which brings difficulties to recovery and application

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