A kind of preparation method of indoxacarb intermediate

Abstract

The invention relates to a preparation method of indoxacarb intermediate. The preparation method is characterized by comprising the following steps: dissolving intermediate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone into xylene, adding benzyl carbazate and phosphorus pentoxide, separating out phosphoric acid, adding diethoxymethane into reaction liquid, enabling the solvent xylene to flow back on a tower, dropping the obtained reaction liquid into xylene at a constant speed, gathering ethyl alcohol, performing negative pressure desolventizing on obtained reaction liquid, adding a crystallizing agent into the rest liquid, performing cooling crystallization, filtering, and drying, so as to obtain 7-chloroindeno [1,2-e][1,3,4] oxadiazine-2,4a (3H,5H)-dicarboxylicacid-4a-methyl-2-benzylester. The method is convenient to operate, increases the reaction temperature, accelerates the reaction speed, and obviously improves the content and the yield of the intermediate.

Description

technical field [0001] The invention relates to the technical field of pesticide compound synthesis, in particular to a preparation method of an indoxacarb intermediate. Background technique [0002] 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid-4a-methyl-2-benzyl ester is mainly used in the synthesis of Insect agent indoxacarb, synthesized 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid-4a-formazine in the prior art There are many ester-2-benzyl ester process routes, and the reagents used are similar, but most of them are different from the design of the process route. In industrial production, other factors such as efficiency or yield or cost are quite different. [0003] In the existing technology, the reaction solvent is generally ethylene dichloride, and the reaction of the intermediate 5-chloro-2-methoxycarbonyl-2-hydroxyl-1-indanone and benzyl carbazate generates water, in the presence of water In the cyclization reaction,...

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Problems solved by technology

[0002] 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid-4a-methyl-2-benzyl ester is mainly used in the synthesis of Insect agent indoxacarb, synthesized 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid-4a-formazine in the prior art There are many process routes for ester-2-benzyl ester, and the reagents used are similar, but most of them vary with the design of the process route. In industrial production, other factors such as efficiency, yield or cost are quite different.

[0003] In the existing technology, the reaction solvent is generally ethylene dichloride, and the reaction of the intermediate 5-chloro-2-methoxycarbonyl-2-hydroxyl-1-indanone and benzyl carbazate generates water, in the presence of water In the cyclization reaction, the condensate will be decomposed into 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone; and because the reaction solvent is dichloroethane, the reaction temperature is 83 ° C, and the by-product ethanol cannot Effective and timely separation, resulting in insufficient reaction and generation of impurities, resulting in the product 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)- The content of dicarboxylic acid-4a-methyl-2-benzyl ester is low and the yield is not high. The 7-chloroindeno[1,2-e][1,3,4]oxadiazine-2 obtained by this process , The content of 4a(3H,5H)-dicarboxylic acid-4a-methyl-2-benzyl ester is about 91%, and the yield is about 81%

[0004] In the prior art, there is also the use of intermediate 5-chloro-2-methoxycarbonyl-2-hydroxyl-1-indanone to prepare (5-chloro-2,3-dihydro-2-hydroxyl-2-methoxy Carbonyl-1H-indene-ylidene) benzyl hydrazine carboxylate, but most of the processes are more complicated, the solvent used is more expensive, and the yield is lower, which is not conducive to the implementation of industrialization

And mostly used solvent is toluene, and its boiling point is 110 ℃, and the boiling point difference with the by-product ethanol is not as big as the boiling point difference between xylene and ethanol, which causes the by-product ethanol to be difficult to separate from the reaction system, resulting in slow reaction speed and side reactions. production, so that the product content is not high and the yield is low