Synthesis method of (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives

A technology of trifluoromethylpyrazolyl and dimethylpyrazolyl, which is applied in the field of preparation of pyridine derivatives, can solve problems such as the weakening of pyrazole nucleophilicity, and achieve easy derivatization, easy preparation, and wide range of product uses Effect

Inactive Publication Date: 2015-06-03
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Application Information

AI Technical Summary

Problems solved by technology

However, for bis-trifluoromethyl-substituted pyrazoles, the nucleophilicity of pyrazoles is greatly weakened due to the strong electron-withdrawing properties of trifluoromethyl groups, and the above method is no longer suitable for the preparation of bis-trifluoromethyl-substituted pyrazoles.

Method used

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  • Synthesis method of (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives
  • Synthesis method of (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives
  • Synthesis method of (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives

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Experimental program
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Effect test

Embodiment 1

[0026]

[0027] A mixture of 2,6-dibromopyridine 2a (2.37g, 10.0mmol), hydrazine hydrate (20.0mmol) and 20mL n-butanol was stirred and reacted at 120°C for 12 hours. After cooling to room temperature, the volatile components were removed under reduced pressure. The solid was washed three times with water (5mL) and ether (5mL), and dried under vacuum at 50℃ for 2 hours to obtain brown solid 4a as the target product (1.25g, yield 67%) . The target product was confirmed by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry.

Embodiment 2

[0029]

[0030] The reaction steps and operation are the same as in Example 1, and the difference from Example 1 is that 2-bromo-6-(3,5-dimethylpyrazolyl)pyridine (2b) (2.51g, 10.0mmol). After stopping the reaction, the brown solid 4b was obtained as the target product (1.30 g, yield 65%) after the same post-treatment. The target product was confirmed by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Compound 2b was prepared according to literature methods (Sun, X.J.; Yu, Z.K.; Wu, S.Z.; Xiao, W.J. Organometallics 2005, 24, 2959).

Embodiment 3

[0032]

[0033] In a 25mL Schlenk reaction flask, add 2-bromo-6-hydrazine pyridine 4a (187mg, 1.0mmol), hexafluoroacetylacetone (242mg, 1.2mmol), trifluoroacetic acid (50μL) and 15mL tetrahydrofuran in sequence, and stir to react under reflux for 5 hour. After the reaction, the mixture was cooled to room temperature, the volatile components were removed under reduced pressure, and then separated by silica gel column chromatography (eluent: petroleum ether (60-90°C) / diethyl ether, v / v=50:1), A white solid target product 6a (346 mg, yield 94%) was obtained. The target product was confirmed by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry.

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Abstract

The invention discloses a method for synthesizing (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives with potential bioactivity. The method comprises the following step: under heating conditions, carrying out substitution/cyclization/dehydration reaction on the raw material 2-bromopyridine derivatives with hydrazine hydrate and hexafluoroacetylacetone to synthesize the (3,5-bistrifluoromethylpyrazolyl)pyridine. Compared with the reported synthesis methods, the method disclosed by the invention has the advantages of accessible raw material, high synthesis efficiency, easy derivation of the product and the like.

Description

Technical field [0001] The present invention relates to a method for preparing (3,5-bistrifluoromethylpyrazolyl)pyridine derivatives. The easy-to-prepared 2-bromopyridine derivative is used as a raw material to undergo substitution / cyclization / dehydration reaction with hydrazine hydrate and hexafluoroacetylacetone to prepare (3,5-bistrifluoromethylpyrazolyl)pyridine derivative. Compared with the reported preparation method, the present invention has the advantages of easy availability of raw materials, high synthesis efficiency and easy derivatization of products. technical background [0002] (3,5-Bistrifluoromethylpyrazolyl) pyridine derivatives are a class of N-heterocyclic compounds with a wide range of uses. This type of substance not only has potential biological activity, but also can be used to prepare highly active complex catalysts or complexes. 物光材料。 Light-emitting materials. Their potential applications as medicines and luminescent materials have attracted widespread...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D401/04C07D401/14
CPCC07D401/04C07D401/14
Inventor 余正坤杜旺明王连弟
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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