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Preparation method of pyrazole derivative

A technology of pyrazole derivatives and derivatives, applied in organic chemistry and other fields, can solve the problems of target product yield of 35-68%, limitation of substrate universality, yield to be improved, etc., and reach the scope of application of substrates Wide range, reduced environmental pressure, and high atomic utilization

Active Publication Date: 2019-11-22
SHANGHAI INST OF TECH
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Problems solved by technology

This reaction uses a stable, easy-to-handle and odorless solid isocyanide as the "CNN" structure, but this reaction can only give 3-substituted pyrazoles, and the substrate universality is limited
Molybdenum and silver bimetallic catalysts are used in the reaction, and the silver catalyst loading is 50%, which has high cost and great pressure on the environment
Du Jianyu et al. reported the synthesis of a class of imidazoles with the participation of propargyl alcohol under microwave radiation. Using propargyl alcohol derivatives and arylhydrazines as raw materials, acetic acid as a solvent and catalyst, a series of functionalized imidazoles were synthesized. But the yield of the target product of this reaction is only 35-68%, the yield needs to be improved, and the functional groups on the imidazole are limited, only benzene functional groups

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  • Preparation method of pyrazole derivative
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  • Preparation method of pyrazole derivative

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[0031] The present invention is a kind of preparation method of pyrazole derivative, comprises the following steps:

[0032] (1) Add a propargyl alcohol derivative, a halogen source, an acid and a solvent into a sealed tube, mix to obtain a reaction solution, heat, and react at 40-120° C., and the complete disappearance of the propargyl alcohol derivative is monitored by TLC;

[0033] (2) Add hydrazine compounds to the reaction solution obtained in step (1), add saturated brine to quench after reacting for 0.5h-5h, extract the organic phase with ethyl acetate, dry over anhydrous sodium sulfate, concentrate to obtain pyrazole derivatives The product purity can be improved by column chromatography; wherein the molar ratio of propargyl alcohol derivative, halogen source, hydrazine compound and acid is 1: (1.0~2.0): (0.5~3.0): (0.01~0.5); The feed ratio of propargyl alcohol derivative and solvent is 1:5~1:20mmol / mL;

[0034] The preparation method of the present invention uses pr...

Embodiment 1

[0052] A kind of preparation method of pyrazole derivative, pyrazole derivative is specifically 3-phenyl-1H-pyrazole, and its structural formula is as follows:

[0053]

[0054] The preparation process is as follows: add propargyl alcohol derivatives, halogen source and acid in a sealed tube, react under reflux at 101°C, add hydrazine after the complete disappearance of propargyl alcohol derivatives as monitored by TLC, add saturated Quench with saline, extract the organic phase with ethyl acetate, dry over anhydrous sodium sulfate, and concentrate to obtain pyrazole derivatives. The purity of the product can be improved by column chromatography, and the calculated yield is 91.0%. Among them, propargyl alcohol, halogen source, hydrazine, solvent and acid are added as 3-phenylprop-2-yn-1-ol (2mmol), NBS (2mmol), hydrazine hydrate (2.1mmol), dioxane (10 mL) and bismuth triflate (0.1 mmol).

[0055] The prepared product was characterized, and its NMR characterization data wer...

Embodiment 2

[0057] A kind of preparation method of pyrazole derivative, pyrazole derivative is specifically 3-(4-bromophenyl)-1H-pyrazole, and its structural formula is as follows:

[0058]

[0059] The preparation process is as follows: add propargyl alcohol derivatives, halogen source and acid in a sealed tube, react under reflux at 101°C, add hydrazine after the complete disappearance of propargyl alcohol derivatives as monitored by TLC, add saturated Quench with brine, extract the organic phase with ethyl acetate, dry over anhydrous sodium sulfate, and concentrate to obtain pyrazole derivatives. The purity of the product can be improved by column chromatography, and the calculated yield is 89%. Among them, propargyl alcohol, halogen source, hydrazine, solvent and acid are added as 1,3-diphenylprop-2-yn-1-ol (2mmol), NIS (2.2mmol), hydrazine hydrate (3.2mmol) , dioxane (20 mL) and copper triflate (0.3 mmol).

[0060] The prepared product was characterized, and its nuclear magnetic ...

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Abstract

The invention relates to a preparation method of a pyrazole derivative, which comprises the following steps of mixing an propargyl alcohol derivative, a halogen source, an acid and a solvent, and heating to react; adding a hydrazine compound into the reaction solution, and reacting to generate the pyrazole derivative; taking the propargyl alcohol derivative, the halogen source and the hydrazine asthe raw materials, carrying out tandem Meyer-Schuster rearrangement reaction, halogenation and cyclization under the action of acid, thereby realizing the synthesis of the pyrazole derivative. Compared with the prior art, the highest yield of the preparation method can reach 91%, the preparation method has the advantages of being easy to operate, being mild in condition, high in conversion rate,few in by-products and the like, and a brand-new synthesis method is provided for the construction of the pyrazole compounds.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of pyrazole derivatives. Background technique [0002] Pyrazole compounds are widely used in pharmaceutical, agrochemical and material industries. Many biologically active drugs and dyes contain pyrazole rings, such as: anti-inflammatory drug celecoxib (formula 1), insecticide pyridine Chormecarb (Formula 2), Fluorescent Dye Pyrazolin Derivatives (Formula 3), etc. The classic method for synthesizing pyrazole rings is to react 1,3-dicarbonyl compounds with hydrazines (Formula 4). Subsequently, a method of [3+2] cycloaddition to unsaturated bonds using diazo compounds to synthesize pyrazoles was developed (Formula 5). However, due to the high toxicity and explosive characteristics of diazo compounds, the application of this method is limited. Aggarwal's research group used aldehyde and p-toluenesulfonyl hydrazide to react to form a diazonium compou...

Claims

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Application Information

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IPC IPC(8): C07D231/12C07D409/04
CPCC07D231/12C07D409/04Y02P20/55
Inventor 殷燕郭会峰潘万勇张青林裴可可
Owner SHANGHAI INST OF TECH
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