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Synthesis method of polysubstituted oxazole and polysubstituted imidazole

A synthetic method and multi-substitution technology, applied in the field of chemical synthesis of two types of compounds, can solve the problems of high price and achieve the effect of less by-products, shortened steps and simple operation

Inactive Publication Date: 2014-07-16
YANGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] There are also many synthetic methods for substituted imidazoles, among which substituted ethylenedione and aldehydes are used to react, and the method of 2,4,5-trisubstituted imidazoles is mainly limited to the use of special catalysts, such as: HClO 4 / SiO 2 , H 2 SO 4 / SiO 2 , BF 3 / SiO 2 , NaHSO 4 / SiO 2 Or zeolite, etc., these catalysts are either acidic and corrosive, or expensive. At present, the method of simply taking substituted ethylenedione to react under the catalysis of acetic acid to generate 2,4,5-trisubstituted imidazoles has not been reported in the literature.

Method used

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  • Synthesis method of polysubstituted oxazole and polysubstituted imidazole

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0013] Example 1: Preparation of 2,4,5-tribendoxazole and 2,4,5-tribendimidazole:

[0014] Add 1mmol diphendione, 25mmol ammonium acetate and 15ml acetic acid to a 50ml round bottom flask in turn. Heat to 100°C and react for 180min, pour 150ml water into the system, neutralize with saturated aqueous sodium bicarbonate solution until the pH reaches 7 , the system was extracted 3 times with 20ml ethyl acetate, the ethyl acetate layers were combined and spin-dried in vacuum, the residue was chromatographed by silica gel column chromatography (the eluent was ethyl acetate and cyclohexane with a volume ratio of 1:4) mixed solution) to isolate the product.

[0015] Product Identification 2,4,5-tribenzoxazole, white solid, melting point: 113~115°C, yield: 23%.

[0016] 1 H NMR (600 MHz, DCCl 3 ) δ(ppm): 8.177(s, 1H, ArH), 8.166(s, 1H, ArH), 7.745 (s, 1H, ArH), 7.733 (s, 1H, ArH), 7.697 (s, 1H, ArH) , 7.684 (s, 1H, ArH), 7.457-7.507 (m, 3H, ArH), 7.354-7.431 (m, 6H, ArH);

...

example 2

[0022] Example 2: Preparation of 2,4,5-tri-methoxyphenyl oxazole and 2,4,5-tri-methoxyphenyl imidazole:

[0023] Add 1mmol di-p-methoxyphenyl ketone, 25mmol ammonium acetate and 15ml acetic acid in sequence to a 50ml round bottom flask. Heat to 100°C for 180min, pour 150ml water into the system, and neutralize with saturated aqueous sodium bicarbonate solution to When the pH value reached 7, the system was extracted 3 times with 20ml ethyl acetate, the ethyl acetate layers were combined and spin-dried in vacuum, and the residue was subjected to thin chromatography on silica gel column chromatography (the eluent was ethyl acetate and cyclohexane with a volume ratio of 1:4 mixed solution) to isolate the product.

[0024] Product identification 2,4,5-tri-p-methoxyphenyloxazole, melting point: 138~139°C white solid, yield: 22%.

[0025] 1c 1 H NMR (600 MHz, CDCl 3 ) δ(ppm): 8.084 (s, 1H, ArH), 8.069 (s, 1H, ArH), 7.643 (s, 1H, ArH), 7.629 (s, 1H, ArH), 7.589 (s, 1H, ArH) , 7.5...

example 3

[0031]Example 3: Preparation of 2,4,5-tri-p-chlorophenyloxazole and 2,4,5-tri-p-chlorophenylimidazole:

[0032] Add 1mmol of di-p-chlorophenyl ketone, 25mmol of ammonium acetate and 15ml of acetic acid to a 50ml round bottom flask in turn. Heat to 100°C for 180min, pour 150ml of water into the system, and neutralize to pH with saturated aqueous sodium bicarbonate solution value reached 7, the system was extracted 3 times with 20ml ethyl acetate, the ethyl acetate layers were combined and spin-dried in vacuum, the residue was thinly chromatographed by silica gel column chromatography (the eluent was ethyl acetate and cyclohexane with a volume ratio of 1 :4 mixed solution) to isolate the product.

[0033] Product identification 2,4,5-tri-p-chlorophenyloxazole, melting point: 155~156°C, white solid, yield: 33%.

[0034] 1 H NMR (600 MHz, CDCl 3 ) δ(ppm): 8.068 (s, 1H, ArH), 8.054 (s, 1H, ArH), 7.635 (s, 1H, ArH), 7.622 (s, 1H, ArH), 7.579 (s, 1H, ArH) , 7.565 (s, 1H, ArH), 7....

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Abstract

The invention discloses a synthesis method of polysubstituted oxazole and polysubstituted imidazole, and relates to the technical field of chemical synthesis of two compounds. The synthesis method comprises the following steps: firstly, mixing and stirring o-dione, ammonium acetate and acetic acid, then heating to 95-105DEG C, reacting for 170-190 minutes, adding water after the reaction is over, regulating the pH value of the system to be 7 through saturated sodium bicarbonate, extracting the mixture with ethyl acetate, then evaporating to remove a solvent, and performing column chromatography on residues to simultaneously obtain tri-substituted oxazole and tri-substituted imidazole. The polysubstituted oxazole and polysubstituted imidazole can be simultaneously synthesized through one-step reaction, compared with the similar multi-step methods, the steps of the method are shortened, the technological process is simple to operate, and expensive or high-pollution substances are ot needed to be adopted as catalysts. The prepared products are higher in purity, and fewer in side products.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis of two types of compounds. Background technique [0002] Substituted oxazoles have attracted the attention of scientists because of their good physiological activities. There are many synthetic methods for substituted oxazoles, such as: benzoin can react with nitrile or formamide under the action of sulfuric acid to generate substituted oxazoles, or oxazoles can be synthesized in chlorine Under the catalysis of aluminum and trifluoromethanesulfonic acid, react with halides to synthesize substituted oxazoles. All these methods usually use strong acidic substances as catalysts, and replace ethylene dione with acetic acid to synthesize 2,4,5-trisubstituted oxazoles in the next step. method has not been reported in the literature. [0003] There are also many synthetic methods for substituted imidazoles, among which substituted ethylenedione and aldehydes are used to react, and the method ...

Claims

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Application Information

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IPC IPC(8): C07D263/32C07D233/58C07D233/64
CPCC07D233/58C07D233/64C07D263/32
Inventor 景崤壁陆海龙王磊谭晓东
Owner YANGZHOU UNIV