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Preparing method of 2-substituted benzoxazole compounds

A compound and oxazole technology, applied in the field of preparation of 2-substituted benzoxazole compounds, can solve the problem that reactants are unstable, are not suitable for large-scale safe production of 2-substituted benzoxazole compounds, and are unfavorable. industrialization, etc.

Active Publication Date: 2015-04-22
INNER MONGOLIA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the preparation of 2-substituted benzoxazole by hydrocarbon activation reaction requires the use of noble metals, ligands, etc., so the price is relatively expensive, which is not conducive to the industrialization of the reaction
For other reactions using o-hydroxyaniline compounds as substrates, the raw materials are more expensive and less stable
So far, it is usually adopted to synthesize ortho-aminophenol, carboxylic acid and its derivatives under strong acid step by step or one-pot method at high temperature (Heine D.W., Alheim R.J., Leavitt J.J. The use of polyphosphoric acid in the synthesis of 2- aryl-and 2-alkyl-substituted benzothiazoles, benzoxazoles and benzothiazoles[J].Journal of the American Chemical Society,1957,79:427-429.; Terashima M.,Ishi i M.,Kanaoka Y.A faci le synthes is of 2 -substituted benzoxazoles[J].Synthes is,1982,484-485.), but in the production and preparation process, due to problems such as unstable reactants and harsh preparation process conditions, these preparation methods are not suitable for 2-substituents Large-scale safe production of benzoxazole compounds

Method used

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  • Preparing method of 2-substituted benzoxazole compounds
  • Preparing method of 2-substituted benzoxazole compounds
  • Preparing method of 2-substituted benzoxazole compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment 1: the preparation of 2-phenylbenzoxazole

[0023]

[0024] (1) Synthesis of the substrate: Take 3.6 mmol o-nitrophenol into a flask, add 1 mL pyridine, mix well to obtain a dark brown liquid. Add 3.9 mmol of benzoyl chloride to obtain a light yellow emulsion, and stir magnetically for 4 h at room temperature. The product was extracted (water was added to quench the reaction, and saturated sodium chloride was added to prevent emulsification), and the organic phase was obtained by standing at room temperature, which was dried at room temperature for 1 hour. The obtained dried product was separated by column chromatography, and the eluted product was spin-dried using a rotary evaporator to obtain the reaction raw material.

[0025] (2) Synthesis of 2-phenylbenzoxazole: get 1.0 mmol of substrate and put it into a flask, add 4.0 mmol of ammonium formate, 20 mL of glacial acetic acid, and finally add 10% catalyst 5% palladium carbon of raw material content. R...

Embodiment 2

[0026] Embodiment 2: the preparation of 5-methyl-2-benzoxazole

[0027]

[0028] (1) Synthesis of the reaction substrate: 3.6 mmol of 4-methyl-2-nitrophenol was put into a flask, 1 mL of pyridine was added, and a dark brown liquid was obtained by uniform mixing. Add 3.9 mmol of benzoyl chloride to obtain a light yellow emulsion, and stir it magnetically for 4 hours at room temperature. The product was extracted (water was added to quench the reaction, and saturated sodium chloride was added to prevent emulsification), and the organic phase was obtained by standing at room temperature, which was dried at room temperature for 1 hour. The obtained dried product was separated by column chromatography, and the eluted product was spin-dried using a rotary evaporator to obtain the reaction raw material.

[0029] (2) Preparation of target compound: put 1.0 mmol of substrate into a flask, add 4.0 mmol of ammonium formate, 20 mL of glacial acetic acid, and finally add catalyst palla...

Embodiment 3

[0030] Example 3: 5-tert-butyl-2-benzoxazole

[0031]

[0032] (1) Synthesis of reaction substrate: Take 3.6 mmol of 4-tert-butyl-2-nitrophenol into a flask, add 1 mL of pyridine, and mix uniformly to obtain a dark brown liquid. Add 3.9 mmol of benzoyl chloride to obtain a light yellow emulsion, and stir it magnetically for 4 hours at room temperature. The product was extracted (water was added to quench the reaction, and saturated sodium chloride was added to prevent emulsification), and the organic phase was obtained by standing at room temperature, which was dried at room temperature for 1 hour. The obtained dried product was separated by column chromatography, and the eluted product was spin-dried using a rotary evaporator to obtain the reaction raw material.

[0033] (2) Preparation of target compound: put 1.0 mmol of substrate into a flask, add 4.0 mmol of ammonium formate, 20 mL of glacial acetic acid, and finally add catalyst palladium carbon with 10% of raw materi...

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Abstract

The invention relates to a preparing method of 2-substituted benzoxazole compounds. The compounds are obtained by reaction of products obtained by reaction of acyl chloride and o-nitrophenol or derivatives thereof under catalyzing of reducing agent ammonium formate, a solvent and palladium-containing agents. According to the method, the reaction condition is mild, environment is protected, raw materials are rich and easy to obtain, operation is easy, yield is high, and various kinds of performance are optimized.

Description

technical field [0001] The present invention relates to a method for preparing compounds in the technical field of pharmaceutical chemistry, in particular to a method for preparing 2-substituent benzoxazole compounds. Background technique [0002] 2-substituent benzoxazole compounds are the main precursors of organic synthesis, and have a wide range of biological activities, so they play an important role in industry, pesticides and medicine. How to synthesize 2-substituent benzoxazole compounds through various efficient ways has aroused people's interest. [0003] In the initial stage of research on the synthesis of 2-substituted benzoxazoles, people used hydrocarbon activation reactions to prepare them. For example, the Sames group (Sezen B., Sames B. Cobalt-catalyzed arylation of azole heteroarenes via direct C-H bond functionalization [J]. Organic Letters, 2003, 5: 3607-3610.) utilizes cobalt acetate and cuprous iodide to co-catalyze , using IMes as ligand, successfull...

Claims

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Application Information

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IPC IPC(8): C07D263/57C07D263/56C07D263/60
CPCY02P20/582C07D263/57C07D263/56C07D263/60
Inventor 邢瑞光李亚男王博
Owner INNER MONGOLIA UNIV OF SCI & TECH
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