Benzoxazole and benzimidazole compounds and preparation method thereof

A technology of benzimidazole and benzoxazole, which is applied in the field of benzoxazole and benzimidazole compounds and their preparation, can solve the problems of complex preparation process, high price, and increased reaction cost, and achieve simple operation and low cost. cheap effect

Inactive Publication Date: 2016-07-20
XINYANG NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods all use some excessive oxidizing agents, such as tert-butyl hydroperoxide, which are prone to explosion and bring some unsafe factors in the actual production process.
At the same time, the biggest problem is that the products prepared by these methods are often limited to 2-aryl quinazolines, and the quinazolines substituted with 2-position fatty acids are not available.
This greatly limits its application prospects
Recently, there are also examples of synthesizing benzoxazole and benzimidazole by hydrogen transfer reaction of o-nitrophenol (o-nitroaniline) and alcohol (benzylamine), but all need to add expensive transition metal nano-catalysts, making the reaction cost Greatly improved, and the preparation process of these transition metal nanocatalysts is relatively complicated, it is difficult to achieve large-scale production (Chem.Commun.2014,50,6145; TetrahedronLett.2015,56,206.)

Method used

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  • Benzoxazole and benzimidazole compounds and preparation method thereof
  • Benzoxazole and benzimidazole compounds and preparation method thereof
  • Benzoxazole and benzimidazole compounds and preparation method thereof

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preparation example Construction

[0045] The preparation method of described a kind of benzoxazole and benzimidazole compound, comprises the following steps:

[0046] a) amino acid with structure (I) and o-nitrophenol (o-nitroaniline) compound with structure (II) can be obtained with structure (III) by stirring and heating in a solvent under the catalysis of a base Benzoxazole and benzimidazole compounds of the present invention:

[0047]

[0048] Among them, R 1 is aryl, substituted aryl or alkyl; R 2 is fluorine, chlorine, methoxy or methyl; X is oxygen, nitrogen or nitrogen methyl.

[0049] R 1 Is aryl, said aryl is phenyl or naphthyl; said R 1 is a substituted aryl group, and the substituted aryl group is p-chlorophenyl, p-methylphenyl, 3,4-dimethoxyphenyl, p-methoxyphenyl, m-methoxyphenyl, o-methoxyphenyl Oxyphenyl, p-trifluoromethylphenyl, p-tert-butylphenyl, p-fluorophenyl, ethyl p-formate phenyl or p-bromophenyl; the R 1 is an alkyl group, and the alkyl group is methyl, n-propyl, tert-butyl or...

Embodiment 1

[0058] In a clean and dry 10 ml Schlenk reaction tube, add 35 mg of o-nitrophenol, 113 mg of phenylglycine, and 69 mg of potassium carbonate in sequence, use 1 ml of toluene as a solvent, seal the reaction tube, and react at 130°C for 24 hours . After the reaction, the reaction mixture was directly spin-dried by a rotary evaporator, and then separated by a silica gel column using petroleum ether and ethyl acetate at a volume ratio of 30:1 as eluents to obtain 46 mg of a white solid with a yield of 95%.

[0059] The proton nuclear magnetic resonance spectrum of the product prepared in this embodiment is as follows: Figure 1a As shown, the carbon NMR spectrum is as Figure 1b shown. It can be confirmed from the spectrum that the obtained product is 2-phenylbenzoxazole.

Embodiment 2

[0061] In a clean and dry 100 ml Schlenk reaction tube, add 700 mg of o-nitrophenol, 2260 mg of phenylglycine, and 1680 mg of potassium tert-butoxide in sequence, use 30 ml of toluene as solvent, seal the reaction tube, and react at 130°C 24 hours. After the reaction, the reaction mixture was directly spin-dried by a rotary evaporator, and then separated by a silica gel column using petroleum ether and ethyl acetate at a volume ratio of 30:1 as eluents to obtain 880 mg of a white solid with a yield of 90%.

[0062] The proton nuclear magnetic resonance spectrum of the product prepared in this embodiment is as follows: Figure 1a As shown, the carbon NMR spectrum is as Figure 1b shown. It can be confirmed from the spectrum that the obtained product is 2-phenylbenzoxazole.

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Abstract

The invention discloses a preparation method of benzoxazole and benzimidazole compounds. A specific structural formula of the benzoxazole and benzimidazole compounds is described in the specification, wherein R1 is aryl, substituted aryl or alkyl; R2 is fluorine, chlorine, methoxyl or methyl; and X is oxygen, nitrogen or nitrogen methyl. The preparation method comprises the following steps: taking amino acid and o-nitrophenol (ortho-nitroaniline) compounds sold on the market as starting materials of reaction, and stirring and heating in a solvent under the catalytic action of an alkaline reagent, so that various substituted benzoxazole and benzimidazole compounds can be obtained with high yield. Reaction conditions are mild, no extra oxidizing agent, reducing agent, ligand or transition metal catalyst needs to be added. The preparation method has the advantages of low cost, simple operation and realization of mass production. Experimental results show that the yield of the obtained benzoxazole and benzimidazole compounds can reach 95%.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a benzoxazole and benzimidazole compound and a preparation method thereof. Background technique [0002] Benzoxazole and benzimidazole compounds are abundant in nature, including biomacromolecules, drug molecules and natural products, and they are a very important class of organic compounds. Benzoxazole and benzimidazole compounds are widely used, and can be used as intermediates of pesticides, spices, and medicines, bioactive molecules such as synthetic proteins, and monomers of functional materials (J.Med.Chem.1995,38,1084; J. Med. Chem. 1991, 42, 4172; J. Med. Chem. 2006, 49, 179.). [0003] Because of the importance of benzoxazole and benzimidazole compounds, they are widely concerned by the chemical, biological and medical circles. However, unfortunately, the traditional preparation method of benzoxazole and benzimidazole compounds is mainly realized by oxidative condensa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D263/57C07D263/54C07D235/18
CPCC07D235/18C07D263/54C07D263/57
Inventor 唐林谭美容
Owner XINYANG NORMAL UNIVERSITY
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