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A kind of electrocatalysis prepares the method for benzimidazolone

An electrode and phenylurea technology, applied in the field of preparation of benzimidazolones, can solve problems such as residual metal ions

Inactive Publication Date: 2021-07-30
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, transition metal catalysis usually requires the introduction of directing groups, and the use of highly toxic or (and) expensive metal catalysts is likely to cause metal ion residues; non-metal catalysis requires the addition of equivalent or excess redox to the reaction system. Reagent

Method used

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  • A kind of electrocatalysis prepares the method for benzimidazolone
  • A kind of electrocatalysis prepares the method for benzimidazolone
  • A kind of electrocatalysis prepares the method for benzimidazolone

Examples

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Embodiment 1

[0012] Embodiment 1, prepare N-(4-chlorophenyl) benzimidazolone by cyclization of three substituted phenyl ureas as an example to illustrate the reaction operation and detect the influence of different electrolytes on the cyclization reaction of the present invention (taking I-1 compound as example)

[0013]

[0014] Trisubstituted phenylurea (0.2mmol), different reaction solvents (12ml) (methanol, hexafluoroisopropanol, isopropanol, (tetrahydrofuran:methanol), acetonitrile, (methanol:water)), sodium methoxide (0.2mmol ) and tetramethylammonium tetrafluoroborate (0.2mmol), add in the three-necked flask successively, and insert C electrode in the bottleneck of both ends of the reaction flask as the positive electrode and the Pt electrode as the negative electrode. . The reaction solution was filtered to obtain a filtrate, and the cyclization product was separated by column chromatography. The calculated separation yield is shown in Table 1, wherein, the yield of the target...

Embodiment 2

[0018] Embodiment 2, the influence of reaction temperature on the cyclization reaction of the present invention

[0019] Except for different reaction temperatures (30°C, 60°C, 90°C), the rest of the reaction conditions were the same as in Example 1, and the influence of the reaction temperature on the yield of the cyclization reaction was detected. After the reaction, the separation and yield measurement results of the target product imidazolone are shown in Table 2, indicating that there is an optimum value for the yield of the cyclization reaction as the reaction temperature changes, and the optimum reaction temperature is set at 60°C.

[0020] The influence of table 2 different reaction temperature on cyclization reaction

[0021] Reaction temperature (°C) 30 60 90 Separation yield (%) 43 85 62

Embodiment 3

[0022] Embodiment 3, the impact of different bases on the cyclization reaction of the present invention

[0023] Except that the reaction base is different (sodium methoxide, sodium carbonate, sodium tert-butoxide, cesium carbonate), other reaction conditions are the same as in Example 1, and the influence of the type of base on the yield of the cyclization reaction is detected. After the reaction finishes, the separation yield rating result of target product imidazolone is as shown in table 3, shows that stronger base all can promote cyclization reaction, and the effect of sodium methylate in the tested base is the best.

[0024] The influence of table 3 different bases on the cyclization reaction

[0025] alkali Sodium methoxide Sodium carbonate Sodium tert-butoxide cesium carbonate Separation yield (%) 85 67 30 20

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Abstract

The invention discloses a method for preparing benzimidazolone by electrocatalysis. The method is to dissolve the trisubstituted phenylurea in a three-necked flask equipped with an organic solvent, and insert a Pt electrode as a negative electrode and a C electrode as a positive electrode in the bottlenecks at both ends of the flask, add alkali and electrolyte, and heat React in air or argon atmosphere for 3-12 hours to obtain benzimidazolone; the molar ratio of the trisubstituted phenylurea to the base is 1:1-1:5, and the molar ratio of the trisubstituted phenylurea to the electrolyte The ratio is 1:1‑1:5. This method overcomes needing to adopt precious metal reagent in the prior art, strong oxidant, high temperature etc. deficiency, and reaction has following advantage: 1) uses electric current as oxidant, has avoided using strong oxidant and expensive chemical oxidant; 2) no transition metal catalysis, avoiding the residue of heavy metal ions in the product; 3) no need for inducing groups, avoiding the redundant steps of introducing inducing groups and removing inducing groups. The synthesis method disclosed by the invention will play an important role in the preparation of benzimidazolone.

Description

technical field [0001] The present invention relates to a method for preparing benzimidazolone, in particular to a method for preparing benzimidazolone in an argon or air atmosphere with a trisubstituted phenylurea under the action of a base and an electric current. Background technique [0002] Benzimidazolone derivatives are widely used in the fields of dyes and medicine, especially in the field of medicine, the derivatives with benzimidazolone as the core structure have more pharmacological activities and the like. The preparation method of benzimidazolone mainly includes transition metal catalyzed method (Barbero, N; Tetrahedron 2008,64,7283; Beyer, Astrid et al, Organic Letters, 2011, 13(11), 2876-2879; and referenced literature) , non-metal catalysis (Yu, Jipan et al, European Journal of Organic Chemistry, 2015(26), 5869-5875; Meng, Yinggao et al, New Journal of Chemistry, 2018, 42(16), 13790-13796; and the references it cites). Among them, transition metal catalysis...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D235/26C25B3/00
CPCC25B3/00
Inventor 李江胜杨盼盼谢欣芸姜思
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY