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A kind of preparation method of isoxazole compound and its intermediate

A compound and isoxazole technology, applied in the field of organic synthesis, can solve the problems of dangerous post-processing process, many impurities and high cost, and achieve the effects of avoiding safety and three waste problems, high product purity and low cost

Active Publication Date: 2018-08-21
ZHEJIANG ZHUJI UNITED CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This preparation method not only has low yield and many impurities, but also the use of highly toxic cyanide reagents leads to dangerous post-treatment process, high cost and many wastes.

Method used

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  • A kind of preparation method of isoxazole compound and its intermediate
  • A kind of preparation method of isoxazole compound and its intermediate
  • A kind of preparation method of isoxazole compound and its intermediate

Examples

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preparation example Construction

[0035] A preparation method of isoxazole compound includes the following steps:

[0036] Step A, after the compound (I) reacts with the compound (II) at a certain temperature in a solvent and the presence of a base, the reaction is continued with an oxidizing agent to obtain an intermediate compound (III);

[0037] Step B: After the compound (III) is reacted with an acid chlorination reagent, it is reacted with an alcohol at a certain temperature to obtain compound (IV), or compound (III) is reacted with an alkylating reagent at a certain temperature under the action of a base to obtain compound ( IV);

[0038] Step C: In a solvent, compound (IV) is reacted with sulfide (V) at a certain temperature to obtain compound (VI);

[0039] Step D, in the presence of a solvent and a base, compound (VI) and methyl ketone (VII) are condensed at a certain temperature to obtain compound (VIII);

[0040] Step E: In the solvent, after the compound (VIII) and the orthoformate (IX) undergo an etherific...

Embodiment 1

[0060] Example 1: Preparation of 4-chloro-3-nitrobenzotrifluoride

[0061] In a 1000mL three-necked flask, add 400g p-chlorobenzotrifluoride, add dropwise a mixed acid of 273g 98% sulfuric acid and 190g 98% nitric acid at 30°C, continue the reaction for 4 hours after the addition is complete, separate the organic layer, and wash the organic layer with water Two times, 480 g of 4-chloro-3-nitrobenzotrifluoride was obtained.

Embodiment 2

[0062] Example 2: Preparation of 2-nitro-4-trifluoromethylbenzoic acid

[0063] In a 1000 mL three-necked flask equipped with a thermometer, 500 g of DMF, 180 g of potassium carbonate, and 78 g of ethyl cyanoacetate were added. Add 150 g of 4-chloro-3-nitrobenzotrifluoride to control the temperature of the reactant within 50° C., after the addition is complete, continue to stir and react for 1 hour. Drop 230g 35% H 2 O 2 After the dropwise addition is completed, the reaction is continued for 2 hours, the hydrogen peroxide is quenched, the solution is removed, water is added, acidified with hydrochloric acid, filtered, washed with water, and dried to obtain 149 g of 2-nitro-4-trifluoromethylbenzoic acid. 1 H-NMRδppm(DMSO-d 6 ): 14.39 (br, 1H), 8.46 (s, 1H), 8.21 (d, J=8.0 Hz, 1H), 8.09 (d, J=8.0 Hz, 1H).

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Abstract

Disclosed is a preparation method for an isoxazole compound and an intermediate thereof, the method comprising: a compound (I), as the starting material, is subjected to a substitution reaction with a compound (II) in the presence of a base, and subsequently to an oxidation reaction to prepare an intermediate acid (III); the intermediate acid (III) is methyl esterified to obtain an intermediate (IV); the intermediate (IV) is subjected to thionation to obtain an intermediate (VI); the intermediate (VI) is condensed with cyclopropyl methanone under a basic condition to obtain an intermediate (VIII); the intermediate (VIII) is subjected to alkene etherification reaction with ortho-formate and cyclized with hydroxylamine hydrochloride to obtain an intermediate (X); the methylthio of the intermediate (X) is oxidized by hydrogen peroxide to obtain isoxazole compound (XI). The starting material used in the present preparation method is readily available, and the preparation method has high productivity and purity, produces less industrial waste water, gas and residue, and has low cost and good industrial value.

Description

Technical field [0001] The invention belongs to the field of organic synthesis, and specifically relates to a method for synthesizing isoxazole compounds and intermediates thereof. Background technique [0002] Isoxazole compounds are an important class of organic compounds, which are widely used in the fields of medicine and pesticides. For example, isoxaflutole is a new herbicide developed by Bayer, which is widely used in corn and sugarcane fields to control gramineous weeds and broadleaf weeds. CN1069267, CN1057524, and CN1135210 disclose the preparation method of isoxaflutole. Its synthesis process is based on 2-nitro-4-trifluoromethyl benzoic acid (a) as a raw material and undergoes methyl esterification to obtain 2-nitro- Methyl 4-trifluoromethyl benzoate (b), intermediate (b) is reacted with sodium methyl mercaptan to obtain methyl 2-methylthio-4-trifluoromethyl benzoate (c), intermediate (c) ) Is condensed with cyclopropyl ketone under alkaline conditions to obtain 3-c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D261/08C07C205/58C07C201/12C07C323/62C07C319/14
CPCC07C201/12C07C205/58C07C319/14C07C323/62C07D261/08
Inventor 苏叶华史界平陆建鑫张天浩蔡国平虞小华陈邦池
Owner ZHEJIANG ZHUJI UNITED CHEM
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