Preparation method of diclosulam

Abstract

The invention provides a preparation method of diclosulam and belongs to the technical field of chemical synthesis. The preparation method comprises the following steps: taking 2,2'-dithio-bis(5-ethyoxyl-7-fluoro[1,2,4]triazole[1,5]pyrimidine) as a raw material, and dropwise adding sulfonyl chloride in the presence of sodium nitrate for carrying out chlorosulfonylation to obtain 2-chlorosulfonyl-5-ethyoxyl-7-fluoro[1,2,4]triazole[1,5]pyrimidine; and carrying out sulfonylation on the 2-chlorosulfonyl-5-ethyoxyl-7-fluoro[1,2,4]triazole[1,5]pyrimidine and 2,6-dichloroaniline in the presence of a catalyst DMAP, so that the diclosulam is obtained. The preparation method provided by the invention has the advantages that the yield and quality are basically consistent with the traditional technology when the diclosulam is obtained by adopting the technology, the problems that usage amount of a highly toxic product chlorine is large and potential safety hazards exist in the traditional technology are solved, the total molar yield reaches more than 80%, and the diclosulam is applicable to industrial production application.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a preparation method of diclosulam. Background technique [0002] Diclosulam was developed by Tao Nongke [US5010195], a triazolopyrimidine sulfonamide herbicide and an acetolactate synthase (ALS) inhibitor that went on the market in 1998. It can be quickly absorbed by weeds through roots and stems to play a role. It is suitable for pre-emergence planting soil treatment of crops soybean and peanut to prevent and control broad-leaved weeds. And for post-emergence control of broad-leaved weeds in winter wheat fields. It is widely used in the United States, South America and other countries. Traditional technology [US5480991][US5461153], prepare 2-chlorosulfonyl-5-ethoxy-7-fluoro[1,2,4]triazole[1,5]pyrimidine (II) by passing chlorine gas, chlorine gas The price is low, but the dosage is large, and due to its high corrosiveness and high toxicity, it has extr...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the above technical and market problems, the present invention provides a preparation method of diclosulam, the preparation method does not use chlorine gas, the operation is simple, the reaction is mild, and the equipment requirements are low; the chlorine gas is replaced by sodium nitrate and sulfonyl chloride system, the product quality and yield are high, and it can solve the defects of high production operation and equipment requirements and large safety hazards caused by the use of chlorine in the traditional process; use 4-dimethylaminopyridine (DMAP) as the catalyst and change from activated amine to Activation of azasulfonyl chloride can also promote the reaction, reduce the cost of equipment modification required to prevent the leakage of dimethyl sulfide odor, and reduce the safety hazards that affect the health of operators