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A kind of synthetic method of preparing benzoxazole compound by catechol compound, ammonium acetate and aldehyde compound

A technology of aldehyde compounds and benzoxazole, which is applied in the field of synthesis of benzoxazole compounds, can solve the problems of expensive, toxic transition metals, trace metal residues in products, etc., to avoid pollution, reduce pollution, improve Effects of Atom Economy

Active Publication Date: 2022-05-24
HUNAN FIRST NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In previous work, although some effective methods using copper or iron as catalyst and catechol as substrate have been successfully developed; however, the use of transition metals is sometimes toxic and expensive and may leave trace metals in the product

Method used

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  • A kind of synthetic method of preparing benzoxazole compound by catechol compound, ammonium acetate and aldehyde compound
  • A kind of synthetic method of preparing benzoxazole compound by catechol compound, ammonium acetate and aldehyde compound
  • A kind of synthetic method of preparing benzoxazole compound by catechol compound, ammonium acetate and aldehyde compound

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preparation example Construction

[0030] A synthesis method for preparing benzoxazole compounds from catechol compounds, ammonium acetate and aldehyde compounds, the raw materials for the preparation of benzoxazole compounds comprising: catechol compounds, ammonium acetate, aldehyde compounds, sodium periodate (NaIO4 )。

[0031] The benzoxazole compounds have the following structural formula:

[0032]

[0033] In one embodiment, in the structural formula, R is a substituent at any one or more positions on the benzene ring, and each R is independently selected from H, methyl, tert-butyl, methoxy, one of the phenyl; R 1 Selected from phenyl, p-toluene, p-methoxyphenyl, p-tert-butylphenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-iodophenyl, p-cyanocyanphenyl, p-trifluoromethylphenyl, p-nitrophenyl, p-hydroxyphenyl, methylparaben phenyl, p-carboxyphenyl, acetamidophenyl, ethynylphenyl, 1-naphtho, 2-thienyl, 2-furan, 3-pyridyl, isopropyl, tert-butyl, cyclohexyl, 3-phenylethyl, N-ethylcarbazolyl.

[0034] In ...

Synthetic example 1

[0052] Synthesis of 5,7-di-tert-butyl-2-phenylbenzo[d]oxazole

[0053] In the reactor, 0.2 mmol 3,5-di-tert-butyl catechol, 0.4 mmol benzaldehyde, 0.4 mmol ammonium acetate, 0.4 mmol NaIO were added to the reactor 4 ，2.0mL EA。 Under a nitrogen atmosphere, continuous stirring at 50 °C for 3h, stopping the reaction, cooling to room temperature, washing with saturated NaCl, and then extracted with ethyl acetate, reduced pressure distillation concentration removed solvent, dried, crude product by column chromatography to obtain the target product, yield 90%. 1 H NMR(400MHz,CDCl 3 ):δ8.36–8.17(m,2H),7.68(s,1H),7.53(s,3H),7.33(s,1H),1.57(s,9H),1.41(s,9H). 13 C NMR(101MHz,CDCl 3 ):δ162.4,147.7,146.9,142.3,133.7,131.2,128.8,127.5,127.4,119.5,114.2,35.1,34.5,31.8,30.0.

Synthetic example 2

[0055] Synthesis of methyl 4-(5,7-di-tert-butylbenzo[d]oxazole-2-yl)benzoate

[0056]In the reactor, 0.2 mmol 3,5-di-tert-butyl catechol, 0.4 mmol methyl 4-formylbenzoate, 0.4 mmol ammonium acetate, 0.4 mmol NaIO were added 4 ，2.0mL EA。 Under a nitrogen atmosphere, continuous agitation at 50 °C for 3h, stop the reaction, cool to room temperature, wash with saturated NaCl, then extract with ethyl acetate, reduce pressure distillation concentrate to remove solvent, dry, crude product by column chromatography to obtain the target product, yield 92%. 1 H NMR(400MHz,CDCl 3 ):δ8.39(q,J＝9.0Hz,1H),7.68(s,1H),7.39(s,1H),1.56(s,2H),1.40(s,2H). 13 C NMR(101MHz,CDCl 3 ):δ160.1,149.2,148.5,147.3,142.2,134.1,133.1,128.1,124.2,120.9,114.7,35.2,34.5,31.8,30.0.

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Abstract

The invention provides a method for preparing benzoxazole compounds from sodium periodate oxidized catechol compounds, ammonium acetate and aldehyde compounds under metal-free conditions. The method uses cheap and easy-to-obtain raw materials to prepare a series of benzoxazole skeleton compounds under mild conditions. In this method, sensitive functional groups such as hydroxyl, carboxyl, and amine groups can be well tolerated; in addition, the iodate after the reaction can be well recovered, which greatly reduces the impact caused by the reaction system. The pollution of the reaction improves the atomic economy of the reaction, and at the same time avoids the pollution of the environment caused by heavy metals and the problem of metal residues in the product. The method can simply construct benzoxazole skeletons with various structures, and has very important significance and application value for the synthesis and application research of such compounds.

Description

【Technical field】 [0001] The present invention relates to the field of organic synthesis, specifically to a synthesis method for preparing benzooxazole compounds from catechol compounds, ammonium acetate and aldehyde compounds. 【Background】 [0002] Benzoxazole compounds are a very important pentaclic cyclic compounds that are widely present in the fields of biomedicine, natural products and functional materials. For example: Tafamidis, as a drug for the treatment of transthyrin family amyloid polyneuropathy, was approved by the U.S. Food and Drug Administration (FDA) in 2019 for the treatment of cardiomyopathy and is also the first drug to treat cardiomyopathy; the medicinal chemical research applications of benzoxazole also include the anti-inflammatory drug Flunoxaprofen, the selective antagonist JTP-426467 and the antibiotic Caboxamycin, among others; in addition, Fluorescent brighteners such as OB containing benzoxazole skeletons have been widely used for the whitening of th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D263/57
CPCC07D263/57
Inventor 董建玉武少峰侯文娟
Owner HUNAN FIRST NORMAL UNIV