Synthesis method for 2-butyl-1, 2-benzisothiazolin-3-ketone

A technology of benzisothiazoline and synthesis method, which is applied in the direction of organic chemistry, can solve the problems of low yield, long reaction steps, and low product quality, and achieve the effects of good product quality, less waste, and reduced process steps

Inactive Publication Date: 2014-03-26
SHOUGUANG SYNTECH FINE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This traditional process method not only has long reacti

Method used

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  • Synthesis method for 2-butyl-1, 2-benzisothiazolin-3-ketone
  • Synthesis method for 2-butyl-1, 2-benzisothiazolin-3-ketone

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preparation example Construction

[0020] The invention provides a method for synthesizing 2-butyl-1,2-benzisothiazolin-3-one, comprising the following steps: 1) reacting o-methylthiobenzoic acid with an acid chloride agent to obtain o-methylthio 2) react o-methylthiobenzoyl chloride with n-butylamine to obtain the corresponding amide compound; 3) then in an organic solvent, the amide compound and the halogenating agent undergo a ring-closure reaction to obtain the target product 2- Butyl-1,2-benzisothiazolin-3-one.

[0021] In step 1) of the present invention, the molar ratio of o-methylthiobenzoic acid and acid chloride agent is 1:1.05-1:2, preferably 1:1.2-1:1.5; the acid chloride agent is thionyl chloride, oxychloride One or more combinations in phosphorus and phosphorus pentachloride, preferably thionyl chloride; the reaction solvent of o-methylthiobenzoic acid and acid chloride agent is o-dichlorobenzene, o-xylene, dichloroethane, benzene , one or more combinations in chlorobenzene, toluene and tetrachlo...

experiment example 1

[0027] Add 83g o-methylthiobenzoic acid and 200g chlorobenzene to a 500ml four-necked flask, raise the temperature to 70-80°C, add 71.5g thionyl chloride dropwise, react for 4h, and recover excess thionyl chloride. Add 56g of triethylamine, keep 75-80°C, and add 44g of n-butylamine dropwise. The reaction was carried out for 3h to obtain the amide compound. At 35-45 ° C, 40 g of chlorine gas was introduced, and the temperature was raised to 70 ° C for 4 h. Add 100g of water, adjust pH=2-3 with sodium carbonate, separate layers, and continue to wash the oil phase with 100g of water. Reduce the recovery solvent, then keep the vacuum degree of about 25mmHg, and distill to obtain 75g of pale yellow liquid, the yield is 73%. (HPLC>98%).

experiment example 2

[0029] Add 83g o-methylthiobenzoic acid and 200g chlorobenzene to a 500ml four-necked flask, raise the temperature to 70-80°C, add 80g thionyl chloride dropwise, react for 4h, and recover excess thionyl chloride. Add 56g of triethylamine, keep 75-80°C, and add 44g of n-butylamine dropwise. The reaction was carried out for 3h to obtain the amide compound. 102 g of bromine was added dropwise at 40-50 °C, and the temperature was raised to 75 °C for 4 h. Add 100g of water, adjust pH=2-3 with sodium carbonate, separate layers, and continue to wash the oil phase with 100g of water. The solvent was reduced and recovered, and then 85 g of light yellow liquid was obtained by distillation under the vacuum degree of about 25 mmHg, and the yield was 82.5%. (HPLC>98%).

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Abstract

The invention belongs to the technical field of fine chemicals, and particularly relates to a synthesis method for 2-butyl-1, 2-benzisothiazolin-3-ketone. The specific steps are as follows: (1) o-(methylthio) benzoic acid reacts with acyl chloride agent, so that o-(methylthio) benzoyl chloride is obtained, wherein the molar ratio of the o-(methylthio) benzoic acid to the acyl chloride agent is 1:1.05 to 1:2, preferably 1:1.2 to 1:1.5; (2) the o-(methylthio) benzoyl chloride reacts with n-butylamine, so that corresponding amide compound is obtained, wherein the molar ratio of the o-(methylthio) benzoyl chloride to the n-butylamine is 1:1.1 to 1:2.5, preferably 1:1.2 to 1:1.8; (3) in organic solvent, the amide compound and halogenating agent conduct ring-closure reaction, so that the target product, 2-butyl-1, 2-benzisothiazolin-3-ketone, is obtained, wherein the synthesis method also includes the steps of washing, recovery and distillation after the reaction between the amide compound and the halogenating agent. Compared with the prior art, the synthesis method overcomes the defects of conventional processes, the process steps are greatly reduced, the process-produced cost is reduced, moreover, the quality of the product is good, the three wastes are little, and the synthesis method has certain industrial value and is worth popularizing and applying.

Description

[Technical field] [0001] The invention belongs to the technical field of fine chemicals, in particular to a method for synthesizing 2-butyl-1,2-benzisothiazolin-3-one. [Background technique] [0002] 2-Butyl-1,2-benzisothiazolin-3-one is widely used as a fungicide and an antifungal agent. Its traditional synthesis method is based on 2,2'-disulfide salicylic acid (DTSA). The raw material is chlorinated by thionyl chloride, chlorinated by chlorine gas, and finally ring-closed by n-butylamine, thereby obtaining 2-butyl-1,2-benzisothiazolin-3-one (BBIT). The traditional process method not only has long reaction steps, but also has low yield and low product quality. [Content of the Invention] [0003] The object of the present invention is to solve the above-mentioned deficiency and provide a kind of synthetic method of 2-butyl-1,2-benzisothiazolin-3-one, not only greatly reduces the process steps, reduces the process generation cost, And the product quality is good, the thre...

Claims

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Application Information

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IPC IPC(8): C07D275/04
CPCC07D275/04
Inventor 戴明本牛司朋苏玉珠
Owner SHOUGUANG SYNTECH FINE CHEM
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