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Preparation method for polyfluoromethylpyrazole compound, and intermediate of compound and preparation method thereof

A compound, methyl technology, applied in the field of preparation, intermediates and preparation of polyfluoromethylpyrazole compounds, can solve the problems of low reaction conversion rate, harsh reaction conditions, low reaction yield, etc.

Active Publication Date: 2017-03-01
LIANHE CHEM TECH YANCHENG +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0027] The technical problem to be solved by the present invention is to overcome the high production cost, harsh reaction conditions, low reaction conversion rate and low by-product production method of 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid Many, low reaction yield, use of highly toxic raw materials, low operating safety, serious environmental pollution and other defects, and provide a preparation method for 3-polyfluoromethylpyrazole compounds and their intermediates

Method used

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  • Preparation method for polyfluoromethylpyrazole compound, and intermediate of compound and preparation method thereof
  • Preparation method for polyfluoromethylpyrazole compound, and intermediate of compound and preparation method thereof
  • Preparation method for polyfluoromethylpyrazole compound, and intermediate of compound and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0127] Add 100g of diethyl malonate (0.625mol) and 315.0g of dehydrated ethanol to the reaction bottle, after completely mixing and dissolving, slowly add the ethanol solution of potassium hydroxide (potassium hydroxide: 35.0 g (0.624mol), ethanol: 315.0g), a white solid was gradually precipitated during the dropwise addition. After the dropwise addition, the reaction solution continued to be stirred at 10-35° C. for about 3.5 hours. Raise the temperature to 79-80°C to reflux the system, then filter while hot to remove dipotassium malonate. The resulting filtrate was cooled to 0°C and filtered to obtain monoethyl malonate potassium salt.

[0128] After the filtrate was concentrated and about 500g of ethanol was further distilled off, the resulting concentrated solution was cooled to 0°C, filtered, and the obtained two parts of monoethyl malonate potassium salt were combined and vacuum-dried to finally obtain 92.06g of monoethyl malonate potassium salt (HPLC purity: 98.8%, yi...

Embodiment 2

[0130] Add 100g of dimethyl malonate (0.757mol) and 350.0g of anhydrous methanol to the reaction flask, after completely mixing and dissolving, slowly add potassium hydroxide methanol solution (potassium hydroxide: 42.3 g (0.754mol), methanol: 350.0g), white solids gradually precipitated during the dropwise addition. After the dropwise addition, the reaction solution continued to be stirred at 10-35° C. for about 3.5 hours. After heating up to 65-68°C to reflux the system, filter while hot to remove dipotassium malonate. The resulting filtrate was cooled to 0°C and filtered to obtain monomethyl malonate potassium salt.

[0131] After the filtrate was concentrated and about 550 g of methanol was further distilled off, the resulting concentrated solution was cooled to 0°C and filtered. After the two parts of monomethyl malonate potassium salt were combined, they were vacuum-dried to obtain 98.78 g of monomethyl malonate potassium salt (HPLC purity: 99.1%, yield: 82.80%).

Embodiment 3

[0133] Add 100g of diethyl malonate (0.625mol) and 315.0g of dehydrated ethanol to the reaction flask, after completely mixing and dissolving, slowly add ethanol solution of sodium hydroxide (sodium hydroxide: 25.0 g (0.624mol), ethanol: 315.0g), and a white solid slowly precipitated out during the dropwise addition. After the dropwise addition, the reaction solution continued to be stirred at 10-35° C. for about 3.5 hours. After heating up to 79-80°C to reflux the system, filter while hot to remove disodium malonate. After about 500 g of ethanol was evaporated from the obtained filtrate, the obtained concentrated solution was cooled to 0° C., filtered, and the obtained monoethyl malonate sodium salt was vacuum-dried to obtain 34.30 g of monoethyl malonate sodium salt (HPLC purity: 98.6%, Yield: 35.12%).

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Abstract

The invention discloses a preparation method for a polyfluoromethylpyrazole compound, and an intermediate of the compound and a preparation method thereof. The invention provides a preparation method for a compound 1 as defined in the specification. The preparation method comprises a step of subjecting a compound 2 as defined in the specification and methylhydrazine to a ring-closure reaction in an organic solvent so as to obtain the compound 1, wherein R<1> is a C1-4 alkyl group, R<2> is a methyl or ethyl group and x is 2 or 3. The preparation method provided by the invention uses cheap and easily available raw materials and is mild in reaction conditions, safe to operate, environment friendly, low in production cost, high in reaction conversion rate, low in the content of isomer in by-products, high in reaction yield and product purity and suitable for industrial production.

Description

technical field [0001] The invention specifically relates to a preparation method, an intermediate and a preparation method of polyfluoromethylpyrazole compounds. Background technique [0002] 3-Difluoromethyl-1H-methylpyrazole-4-carboxylic acid is an important pesticide intermediate, which is used to synthesize flufenapyroxad, one of the main active ingredients of BASF’s new fungicide Priaxor, available To produce Bayer's fungicide Bixafen and Syngenta's fungicide Isopyrazam. 3-trifluoromethyl-1H-methylpyrazole-4-carboxylic acid is also an important pesticide intermediate used to produce the fungicide Penthiopyrad developed by Mitsui Corporation. [0003] At present, there are mainly the following synthetic methods of 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid: [0004] 1. Using ethyl polyfluoroacetate as a raw material, 3-difluoromethyl-1H-methylpyrazole-4-carboxylic acid is obtained through Claisen condensation, ethoxymethenation, ring closure, saponification,...

Claims

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Application Information

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IPC IPC(8): C07D231/14C07C69/738
CPCC07C69/738C07D231/14
Inventor 樊小彬银亮王海洋林行军陈冬辉何俊冯燕秋熊亮
Owner LIANHE CHEM TECH YANCHENG
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