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A method for synthesizing 1-difluoromethylimidazole and derivatives thereof

A technology of difluoromethylimidazole and its synthesis method, which is applied in the direction of organic chemistry, can solve the problems of high price and ozone depletion, and achieve the effects of low price, low environmental hazards and mild reaction conditions

Inactive Publication Date: 2019-08-23
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, because difluorochloromethane commonly used in these methods can deplete ozone, and other difluorocarbene reagents need to be prepared and are expensive, considering the feasibility of environmental protection and scale-up production, it is urgent to find a new and inexpensive The Inexpensive Difluorocarbene Reagent Used in the Synthesis of 1-Difluoromethylimidazole and Its Derivatives

Method used

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  • A method for synthesizing 1-difluoromethylimidazole and derivatives thereof
  • A method for synthesizing 1-difluoromethylimidazole and derivatives thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Add benzimidazole (0.5mmol), ethyl difluorobromoacetate (0.6mmol), potassium hydroxide (0.5mmol), and acetonitrile (1ml) to a 25mL pressure-proof bottle in turn, seal the pressure-proof bottle, and put it into the pre- Heated to 60 ° C in an oil bath for 6h. After the reaction, cool to room temperature. 30 mL of water was added to the reaction solution, and extracted with ethyl acetate, the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to obtain a crude product. The crude product was subjected to column chromatography using a mixed solvent of petroleum ether and ethyl acetate as the eluent to obtain the target compound with a yield of 94%.

Embodiment 2

[0020] Add 5,6-dimethylbenzimidazole (0.5mmol), ethyl difluorobromoacetate (0.6mmol), potassium hydroxide (0.5mmol), and acetonitrile (1ml) to a 25mL pressure-resistant bottle in sequence, and seal the pressure-resistant bottle, and put it into an oil bath preheated to 60°C to react for 6h. After the reaction, cool to room temperature. 30 mL of water was added to the reaction solution, and extracted with ethyl acetate, the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to obtain a crude product. The crude product was subjected to column chromatography using a mixed solvent of petroleum ether and ethyl acetate as the eluent to obtain the target compound with a yield of 87%.

[0021] The benzimidazole was replaced by 5-nitrobenzimidazole, and the yield was 79%. The benzimidazole was replaced by 2-phenylbenzimidazole, and the yield was 93%. The benzimidazole was replaced by imidazole, and the yield was 76%. The benzimidazole...

Embodiment 3

[0023] Reaction steps are identical with embodiment 1, difference is:

[0024] The amount of potassium hydroxide used was 0.75 mmol, and the yield of 1-difluoromethylbenzimidazole was 95%.

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Abstract

The invention discloses a method for synthesizing 1-difluoromethyl imidazole and a derivative thereof. The method is characterized in that ethyl bromodifluoroacetate, a substrate iminazole and a derivative thereof and alkali are dissolved in a reaction solvent, the mixed liquid is heated and stirred, a difluoromethylation reaction happens, and the substrate is benzimidazole, 2-phenyl benzimidazole, 5-nitrobenzimidazole, 5,6-dimethyl benzimidazole, imidazole, 2-methylimidazole and 2-ethyl imidazole. Ethyl bromodifluoroacetate is adopted as a difluoromethylation reagent, no ozone is consumed, environmental friendliness is achieved, the whole reaction condition is mild and aftertreatment is simple.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 1-difluoromethylimidazole and derivatives thereof. Background technique [0002] Imidazole and its derivatives are important structural units of some biologically active compounds, and have been widely used in medicine, materials science and catalytic reactions. In addition, they can also be used to prepare N-heterocyclic carbene precursors. As a commonly used metal ligand and organic small molecule catalyst, N-heterocyclic carbene has attracted extensive attention from scientific researchers. With the development of fluorine-containing organic synthesis methods, scientists have found that selective fluorination and fluoroalkylation of organic compounds can significantly change their electronic and structural properties. Among them, difluoromethyl-containing compounds have attracted widespread attention due to their potential applications in m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D235/22C07D233/56
Inventor 蔡春朱艳芳
Owner NANJING UNIV OF SCI & TECH
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