Electrochemical synthesis method of 2-substituted benzoxazole derivative

A technology of benzoxazole and synthesis method, applied in the field of electrochemical synthesis of 2-substituted benzoxazole derivatives, can solve the problems of large amount of three wastes, harsh reaction conditions, etc. Implementation value and socio-economic benefits

Active Publication Date: 2021-12-21
CHENGDA PHARM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above method has many shortcomings, such as the use of metal c...

Method used

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  • Electrochemical synthesis method of 2-substituted benzoxazole derivative
  • Electrochemical synthesis method of 2-substituted benzoxazole derivative
  • Electrochemical synthesis method of 2-substituted benzoxazole derivative

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Embodiment 1: the preparation of ethyl 2-benzoxazole carboxylate (Ia)

[0032] N-(2-Hydroxyphenyl)-glycine ethyl ester (59 mg, 0.3 mmol), acetic acid (18 mg, 0.3 mmol), tetrabutylammonium tetrafluoroborate (50 mg, 0.15 mmol) and acetonitrile (6 mL) were added to the reaction into the tube, and insert a mesh glassy carbon electrode and a platinum electrode, adjust the current to a constant current of 8mA, and react at 40°C under nitrogen protection for 24 hours, and obtain orange-yellow solid 2-benzoxazole ethyl carboxylate through silica gel column chromatography Ester (Ia) 43 mg, yield: 74%, melting point 88-91.6 ° C, the structural formula of Ia is:

[0033]

[0034] 1 H NMR (400MHz, CDCl 3 )δ7.89(d, J=8.0Hz, 1H), 7.66(d, J=8.0Hz, 1H), 7.52(t, J=7.6Hz, 1H), 7.45(t, J=7.6Hz, 1H) ,4.55(q,J=7.2Hz,2H),1.49(t,J=7.2Hz,3H); 13 CNMR (100MHz, CDCl 3 )δ156.1, 152.6, 150.7, 140.4, 128.3, 125.4, 122.5, 111.8, 63.6, 14.4; HRMS (ESI): calcd for C 10 h 9 NO 3 (M+H) + :19...

Embodiment 2

[0035] Embodiment 2: the preparation of ethyl 2-benzoxazole carboxylate (Ia)

[0036] N-(2-hydroxyphenyl)-glycine ethyl ester (59mg, 0.3mmol), p-toluenesulfonic acid (52mg, 0.3mmol), tetrabutylammonium tetrafluoroborate (50mg, 0.15mmol) and acetonitrile (6mL) Add it into the reaction tube, and insert the mesh glassy carbon electrode and platinum electrode, adjust the current to a constant current of 8mA, and react at 40°C under nitrogen protection for 24 hours, and separate by silica gel column chromatography to obtain orange-yellow solid 2-benzoxane Ethyl azole carboxylate (Ia) 11 mg, yield: 20%.

Embodiment 3

[0037] Embodiment 3: the preparation of ethyl 2-benzoxazole carboxylate (Ia)

[0038] N-(2-Hydroxyphenyl)-glycine ethyl ester (59 mg, 0.3 mmol), formic acid (14 mg, 0.3 mmol), tetrabutylammonium tetrafluoroborate (50 mg, 0.15 mmol) and acetonitrile (6 mL) were added to the reaction into the tube, and insert a mesh glassy carbon electrode and a platinum electrode, adjust the current to a constant current of 8mA, and react at 40°C under nitrogen protection for 24 hours, and obtain orange-yellow solid 2-benzoxazole ethyl carboxylate through silica gel column chromatography Ester (Ia) 31 mg, yield: 55%.

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Abstract

The invention discloses an electrochemical synthesis method of a 2-substituted benzoxazole derivative. The preparation method comprises the following specific preparation steps: sequentially adding an o-hydroxyaniline derivative, an electrolyte, an additive and an organic solvent by taking an unseparated electrolytic cell as a reactor, respectively inserting a positive electrode and a negative electrode of an electrode into a reaction solution, switching on a constant current, carrying out stirring reaction, and after the reaction is finished, carrying out column chromatography separation to obtain the 2-substituted benzoxazole derivative, wherein a dipeptide substance can be prepared in one step. According to the method, a metal catalyst and an oxidizing agent are not needed, only electro-catalytic oxidation is used, the byproduct is hydrogen, and the method has the advantages that raw materials are easy to obtain, operation is easy, reaction is mild and the like, and has high implementation value and social and economic benefits.

Description

technical field [0001] The invention belongs to the technical field of synthesis of pharmaceutical and chemical intermediates, and in particular relates to an electrochemical synthesis method of 2-substituted benzoxazole derivatives. Background technique [0002] Compounds with benzoxazole as the core are widely found in natural active products and pharmaceutically active molecules, for example, Vyndaqel, which is used for the treatment of transthyretin amyloidosis and whose sales exceed one billion US dollars , non-steroidal anti-inflammatory analgesic flunoprofen (flunoxaprofen), Suvorexant for the treatment of primary insomnia, etc., and the 2-position of benzoxazole derivatives is the main structural modification site And the core position of the pharmacophore. In addition, the 2-substituted benzoxazole derivatives also have many pharmacological activities such as anticancer, antibacterial, anti-inflammatory, and analgesic. The 2-position derivatives of benzoxazole acti...

Claims

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Application Information

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IPC IPC(8): C25B3/05C25B3/07C25B3/09C25B3/23C25B1/02
CPCC25B3/05C25B3/07C25B3/09C25B3/23C25B1/02
Inventor 冯宇黄宗玺葛朝平高莉燕李守鑫俞章丽
Owner CHENGDA PHARM CO LTD
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