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Preparation method of 3-hydroxy-substituted pyrazol

A hydroxyl and pyrazole technology is applied in the field of preparation of 3-hydroxy-substituted pyrazoles, and can solve the problems of troublesome separation process of 3-hydroxy-substituted pyrazole products, low reaction selectivity of 3-hydroxy-substituted pyrazoles, and the like, To achieve the effect of easy availability of raw materials, less by-products and simple operation

Active Publication Date: 2012-07-18
SHENYANG SINOCHEM AGROCHEMICALS R&D CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] This preparation method generates the reaction selectivity of 3-hydroxyl-substituted pyrazole (I) is low, and the generating amount of 5-hydroxyl-substituted pyrazole (IV) is greater than target product; Simultaneously, because 5-hydroxyl-substituted pyrazole and 3- The hydroxy-substituted pyrazole is in the same reaction system, and the separation process to obtain the 3-hydroxy-substituted pyrazole product is troublesome

Method used

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  • Preparation method of 3-hydroxy-substituted pyrazol
  • Preparation method of 3-hydroxy-substituted pyrazol

Examples

Experimental program
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example 1

[0035] Example 1: Preparation of 2-phenyl-1,3-dimethyl-pyrazole-1H-3-ol (compound 35)

[0036]

[0037] Add 30mL of methylhydrazine (95% content) to a 125mL three-necked flask with a thermometer, and control the temperature in an ice bath below 10°C. The ester (refer to Tetrahedron, 2008, 64, 3471-3476 for the synthesis method) was added to the reaction flask (about 10 minutes), and the reaction was stirred at room temperature for about 4 hours after the addition was completed. Liquid chromatographic detection of the raw material 2-methyl-3-carbonylphenylpropionate methyl ester in the reaction liquid has completely reacted. Distilled under reduced pressure at 50°C to recover 28 mL of methylhydrazine solution, and cooled to room temperature to precipitate a pale yellow solid. Add 40mL of water, stir and filter, then wash the filter cake with 40mL of petroleum ether, collect the solid, and dry to obtain 2.82g of 2-phenyl-1,3-dimethyl-pyrazol-3-ol; then wash the washing liqui...

example 2

[0038] Example 2: Preparation of 5-(4-methylphenyl)-1,4-dimethyl-1H-pyrazol-3-ol (compound 37)

[0039]

[0040] Add 40mL of methylhydrazine (95% content) to a 250mL three-necked flask with a thermometer, and control the temperature in an ice bath below 10°C. At this temperature, 5g (22.1mmol) of 3-(4-tolyl)-2 -Methyl-3-carbonylpropionate (refer to Tetrahedron, 2008, 64, 3471-3476 for the synthesis method) was added to methylhydrazine, and stirred at room temperature for about 4 hours. 3-(4-tolyl)-2-methyl-3-carbonyl propionate raw material reacts completely in liquid chromatography detection reaction liquid, follow-up operation is with example 1, obtains 5-(4-tolyl)-1 altogether , 4-Dimethyl-1H-pyrazol-3-ol 3.7g, white solid, content 98.7%, yield 75%, melting point 222-224°C.

example 3

[0041] Example 3: Preparation of 5-(4-methylphenyl)-1,4-dimethyl-1H-pyrazol-3-ol (compound 37)

[0042]

[0043] Add 5g (22.1mmol) of 3-(4-tolyl)-2-methyl-3-carbonylpropionic acid methyl ester, 40mL methylhydrazine (content 40%) aqueous solution and 5g Sodium chloride, during the feeding process, the ice bath temperature was controlled below 10°C, after the feeding was completed, it was reacted at room temperature for 8 hours until the reaction was complete, and solids were continuously precipitated during the reaction process. After the reaction was complete, the filter cake was collected by filtration, washed with 40 mL of petroleum ether, and dried to obtain 2.1 g of the product. The filtrate was extracted with ethyl acetate, dried, rotary evaporated, column chromatography (gradient elution solvent: ethyl acetate: petroleum ether = 1: 3-1) to obtain 0.7g product, a total of 2.8g product was obtained, white solid, content 99.2 %, yield 56%. The melting point is 222-224°...

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Abstract

The invention belongs to the field of organic synthesis, and discloses a preparation method of 3-hydroxy-substituted pyrazol as shown in the formula (I). The response equation is : (a chemical formula), and definition of each substituent group in the formula is shown in a instruction book. Substituted benzene formoxyl ethyl carboxylic acid ester as shown in the formula (II) and substituted hydrazine as shown in the formula (III) serve as raw materials, simultaneously the substituted hydrazine as shown in the formula (III) serves as a solvent, and reaction is carried out at 0-40 DEG C for 5-10 hours. When the substituted hydrazine with low concentration is adopted, inorganic salt is added in a reaction system, and charging ratio of (II), (III) and the inorganic salt is 1: (3-10): (0-1). The preparation method is easy in raw material acquisition, simple in synthetic route, simple and convenient in operation, high in product yield, easy to purify and the like, and applicable to laboratory synthetics and industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 3-hydroxyl-substituted pyrazoles. Background technique [0002] 3-Hydroxy-substituted pyrazoles are an important class of intermediates, which are widely used in the preparation of organic chemicals such as pesticides and medicines, for example, for the preparation of agricultural insecticides and fungicides (WO2010060379A1). There are few bibliographical reports about the preparation method of 3-hydroxyl-substituted pyrazoles. Synlett, 2004, 5: 795-798 gives 3 =H), obtain the method of 3-hydroxyl-substituted pyrazole (I) through two-step reaction, but if R 3 Without hydrogen, the method would be difficult to implement. [0003] [0004] J Chem Soc Perkin trans 2:1987, 8:969 provides a method for obtaining 3-hydroxyl-substituted pyrazole (I) while preparing 5-hydroxyl-substituted pyrazole (IV) by analyzing the reaction mechanism. method, ...

Claims

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Application Information

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IPC IPC(8): C07D231/20
Inventor 刘长令郝树林李淼张静
Owner SHENYANG SINOCHEM AGROCHEMICALS R&D CO LTD
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