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Method for preparing oxazole compound

A technology of compounds and oxazoles, which is applied in the field of organic synthesis, can solve the problems of large by-products and low yield of target products, and achieve the effects of short reaction time, mild reaction conditions and high reaction efficiency

Active Publication Date: 2020-05-15
ZHEJIANG NHU CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a kind of method for preparing oxazole compound, aim to solve the target product yield that exists in the prior art phosgene and substrate amino acid ester derivative reaction preparation oxazole compound process is relatively low, Problems with larger amounts of by-products

Method used

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  • Method for preparing oxazole compound
  • Method for preparing oxazole compound
  • Method for preparing oxazole compound

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Experimental program
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Effect test

preparation example Construction

[0043] According to the method for preparing oxazole compounds provided by the present invention, it has the following reaction formula:

[0044]

[0045] The inventors of the present invention have proved according to experimental results that when using phosgene or diphosgene or triphosgene to prepare oxazole compounds, adding a phosphorus-containing or boron-containing compound with a specific structure can promote the efficient progress of the main reaction, while the side effects The reaction is inhibited. The inventors have found through experimental research that according to the method for preparing oxazole compounds provided by the present invention, the target product oxazole compounds represented by formula (V) can be obtained in high yield, and the formation of by-products can be greatly suppressed at the same time.

[0046] According to the method for the preparation of oxazole compounds provided by the present invention, the trihydrocarbyl phosphine oxide repr...

Embodiment 1

[0062] (using phenylboronic acid as auxiliary agent):

[0063] In the reaction flask, add 24g N-ethoxyoxalylalanine ethyl ester (0.11mol), 0.14g phenylboronic acid (1.1mmol) and 42.4g triethylamine (0.42mol), after dissolving with 45mL chloroform, Triphosgene solution (13.1g, 0.044mol, dissolved in 50mL chloroform) was added dropwise at 0-5°C with stirring, and the dropwise addition was completed in about 1 hour, then heated to 50°C for 1 hour, followed by gas chromatography and found that The raw material N-ethoxyoxalylalanine ethyl ester was completely consumed. After reaction finishes, detect by gas chromatography, confirm that gained product is 4-methyl-5-ethoxy oxazole, and its internal standard molar yield is 96% (yield is based on N-ethoxy oxalylalanine ethyl Esters, detected by internal standard method, n-octadecane is internal standard), while only generating 3% (molar yield) of N,N-diethylformyl chloride (yield is based on 3 times of triphosgene, detected by externa...

Embodiment 2-1

[0068] (Using triethyl phosphate as auxiliary agent):

[0069] In the reaction flask, add 30g N-butoxy oxalylalanine n-butyl ester (0.11mol), 0.9g triethyl phosphite (5.5mmol) and 42.4g triethylamine (0.42mol), and use 45mL tris After the methyl chloride is dissolved, triphosgene solution (13.1g, 0.044mol, dissolved in 50mL chloroform) is added dropwise at 0-5°C with stirring, and the dropwise addition is completed in about 1 hour, and then heated to 50°C for 1 hour to react. Gas chromatography followed the reaction and found that the raw material N-butyloxyoxalylalanine n-butyl ester was completely consumed. After reaction finishes, detect by gas chromatography, confirm that gained product is 4-methyl-5-n-butoxy oxazole, and its internal standard molar yield is 95% (yield is based on N-butoxy oxalyl alanamide N-butyl acid, internal standard method detection, n-octadecane is the internal standard), and only generate 4% (molar yield) of N,N-diethylformyl chloride (yield is bas...

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Abstract

The invention relates to a method for preparing an oxazole compound. The method comprises the steps: adding an assistant represented by a formula (I) or (II) or (III) into an organic solvent and organic alkali (especially triethylamine), dropwise adding an organic solution of phosgene or diphosgene or triphosgene to carry out cyclization reaction with a compound (IV), and thus obtaining the product (V) at high yield and greatly inhibiting the generation of byproducts. The reaction conditions are mild, and compared with a method without addition of additives, the method provided by the invention can improve the yield of the product (V) to 95% or above and reduce the yield of byproducts by 10% or above.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for preparing oxazole compounds. Background technique [0002] Oxazole compounds are an important class of heterocyclic compounds. Some compounds with oxazole rings have biological activity and are important pharmaceutical intermediates. For example, 4-methyl-5-alkoxy-substituted oxazoles can be used to synthesize vitamin B6. [0003] US3560516 discloses a method for the preparation of oxazole derivatives using phosgene, the method comprising, in the presence or absence of an organic solvent, phosgene and N-oxalylating in the presence of an organic base such as triethylamine Amino acid ester compounds undergo a cyclization reaction. This method can generally obtain oxazole derivatives in yields of 50-80%. The reason for the lower yield is mainly that in this reaction system, phosgene is very easy to react with triethylamine to generate a large am...

Claims

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Application Information

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IPC IPC(8): C07D263/42
CPCC07D263/42
Inventor 周有桂陈卫勇赵雷黄尖王剑杨运晗陈志荣李浩然
Owner ZHEJIANG NHU CO LTD
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