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Method for preparing isoxadifen

A technology of isoxadifen and diphenylethylene, which is applied in the field of preparation of herbicide safeners, can solve the problems of high cost, high preparation cost, and low yield, so as to increase the yield and reduce the generation of by-products , improve the effect of selectivity

Active Publication Date: 2015-04-08
江苏省农用激素工程技术研究中心有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The deficiency of this document is that: 1,1-diphenylethylene is used to prepare isoxadifen in excess, and 1,1-diphenylethylene is more costly than ethyl 2-chloro-2-oximinoacetate , leading to high preparation cost of this method, which is not suitable for industrial production
The deficiency of this method is: adopt triethylamine to have some by-products to generate as organic base, cause yield to be lower

Method used

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  • Method for preparing isoxadifen

Examples

Experimental program
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Effect test

Embodiment 1）

[0015] The preparation method of the isoxadifen of the present embodiment has the following steps:

[0016] ①Add 16.2g of 1,1-diphenylethylene (0.09mol) and 18.7g of N,N-diethylethanolamine (0.16mol) into 30mL of cyclohexane to obtain mixed solution C.

[0017] ② Add 24.6g of ethyl chlorooximinoacetate (0.16mol) and 80mL of cyclohexane into a 250mL four-necked bottle to obtain mixed solution D.

[0018] ③At room temperature (15°C-25°C, the same below) and under stirring, slowly add the mixed solution C to the four-neck flask dropwise, and continue stirring for 1 hour after dropping.

[0019] ④ After the reaction, add 80mL of water and stir, let stand to separate layers, wash the organic layer three times, anhydrous MgSO 4 Drying, precipitation, and column chromatography yielded 19.5 g of isoxadifen as a white solid, with a yield of 72% (calculated as diphenylethylene) and a purity of 98%.

Embodiment 2）

[0021] ①Add 25.7g of N,N-diethylethanolamine (0.22mol) into 30mL of cyclohexane to obtain mixed solution A.

[0022] ②Put 16.2g of 1,1-diphenylethylene (0.09mol), 33.2g of ethyl chloroximodiacetate (0.22mol) and 80mL of cyclohexane into a 250mL four-neck flask to obtain a mixed solution B .

[0023] ③Under stirring at room temperature, slowly drop the mixed solution A into the four-necked bottle, and continue to stir for 1 hour after the dropping.

[0024] ④ After the reaction, add 80mL of water and stir, let stand to separate layers, wash the organic layer three times, anhydrous MgSO 4 Drying, precipitation, and column chromatography yielded 20.9 g of isoxadifen as a white solid, with a yield of 78% (calculated as diphenylethylene) and a purity of 99%.

Embodiment 3～ Embodiment 4）

[0026] The preparation method of each embodiment is basically the same as that of Example 2, and the differences are shown in Table 1.

[0027] Table 1

[0028]

[0029] Known by embodiment 1 and embodiment 2: adopt the mixed solution that organic base and a part of organic solvent is formed and the mixed solution that 1,1-diphenylethylene and ethyl chloroxime ethyl acetate and another part of organic solvent are mixed Compared with the method of mixing a mixed solution composed of 1,1-diphenylethylene, an organic base and a part of an organic solvent with a mixed solution composed of ethyl chlorooximinoacetate and another part of an organic solvent, the yield can be further improved. Rate.

[0030] It can be seen from Example 2 and Example 3 that the yield is slightly higher when N,N-diethylethanolamine is selected as the organic base than N,N-dimethylethanolamine is used as the organic base.

[0031] Known by embodiment 3 and embodiment 4: select ethyl acetate as organi...

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Abstract

The invention discloses a method for preparing isoxadifen. The method comprises a step of reacting with each other by utilizing 1, 1-diphenylethlene and ethyl chlorooximidoacetate in the presence of organic alkali and an organic solvent, wherein the organic alkali is N, N-dimethylethanolamine or N, N-diethylethylenediamine, the molar ratio of the 1, 1-diphenylethlene to the ethyl chlorooximidoacetate to the organic alkali is 1:(1-4):(1-4), preferably 1:(1.5-2.5):(1.5-2.5). According to the method, the N, N-dimethylethanolamine or N, N-diethylethylenediamine is served as the organic alkali, so that the reaction yield is obviously increased.

Description

technical field [0001] The invention relates to a preparation method of a herbicide safener, in particular to a preparation method of isoxadifen. Background technique [0002] The chemical name of isoxadifen is 4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic acid ethyl ester, which was developed by Aventis Azole safeners. [0003] Chinese patent document CN1133038A discloses a preparation method of isoxadifen: 13.52g (0.075mol) of 1,1-diphenylethylene and 5.06g (0.05mol) of triethylamine are dissolved in 200mL at 0°C After about two hours, 7.58 g (0.05 mol) of ethyl 2-chloro-2-oximinoacetate dissolved in 100 mL of ether was added dropwise, and after stirring continuously at room temperature for 1 hour, 100 mL of water was added. The mixture was then extracted with ether and washed over MgSO 4 After drying, diethyl ether was distilled off, and the residue was purified on a silica gel column to obtain 12.7 g of product. The deficiency of this document is that: 1,1-diphen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D261/04
Inventor 孔繁蕾周月根王慧
Owner 江苏省农用激素工程技术研究中心有限公司