A method for electrochemically synthesizing lactone

An electrochemical and lactone technology, applied in the field of electrochemical synthesis of lactone, can solve the problems of cumbersome process, unfavorable industrial operation and large-scale production, and achieve the effect of simple process, easy control and increased versatility

Inactive Publication Date: 2019-02-15
NANYANG NORMAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But looking at these reported C-H / O-H cross-coupling reaction lactone synthesis methods, most of them need to add transition metal catalysts, photocatalysts or organic small molecule catalysts and oxidants during the preparation process, which often requires post-processing, and the process is cumbersome , not conducive to industrial operation and mass production

Method used

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  • A method for electrochemically synthesizing lactone
  • A method for electrochemically synthesizing lactone
  • A method for electrochemically synthesizing lactone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] (1) Add 40g of raw material 2-phenylbenzoic acid (1aa), 6.6g of electrolyte tetra-n-butylammonium tetrafluoroborate and 50mL of solvent acetonitrile into the electrolytic cell without diaphragm, and then insert the graphite electrode with a current density of 20mA / cm 2 The constant current at 20 o Stirring reaction under C;

[0052] (2) The reaction was tracked by thin layer chromatography. After the reaction was completed, the solvent was spun off under vacuum, and then the lactone product 6 was obtained by recrystallization and separation. H - Benzo[c]chroman-6-one (2aa) 33g, 84% yield.

[0053] 1 H NMR (400 MHz, CDCl 3 ): δ 8.40-8.38 (d, J = 7.9 Hz, 1H), 8.11-8.09(d, J = 8.0 Hz, 1H), 8.05-8.03 (d, J = 7.8 Hz, 1H), 7.83-7.80 (t, J = 7.6 Hz,1H), 7.59-7.55 (t, J = 7.6 Hz, 1H), 7.49-7.45 (t, J = 7.7 Hz, 1H), 7.36-7.31(m, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ 161.1, 151.2, 134.8, 134.7, 130.5, 130.4, 128.8, 124.5, 122.7, 121.6, 121.2, 118.0, 117.7.

Embodiment 2

[0055] (1) Add 108mg of raw material 2-(4-fluorophenyl)benzoic acid (1ab), 342mg of electrolyte tetra-n-butylammonium perchlorate and 10mL of solvent acetone into the electrolytic cell without diaphragm, then insert the platinum plate electrode, and pass The input current density is 10mA / cm 2 The constant current at 5 o Stirring reaction under C;

[0056] (2) Track the reaction by thin-layer chromatography. After the reaction is completed, the solvent is removed under vacuum, and then separated by silica gel column chromatography to obtain the lactone product 3-fluoro-6 H - Benzo[c]chroman-6-one (2ab) 67 mg, yield 63%.

[0057] 1 H NMR (400 MHz, CDCl 3 ): δ 8.38-8.36 (d, J = 7.8 Hz, 1H), 8.05-8.01(m, 2H), 7.85-7.81 (t, J = 7.6 Hz, 1H), 7.59-7.55 (t, J = 7.5 Hz, 1H), 7.09-7.06 (m, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ 164.7-162.2 (d, J F-C = 249.6 Hz),160.7, 152.2-152.1 (d, J F-C = 12.5 Hz), 135.0, 134.2, 130.6, 128.7, 124.4-124.3 (d, J F-C = 9.8 Hz), 121.5, ...

Embodiment 3

[0059] (1) Add 123mg of raw material 2-(4-methylphenyl)-4-chlorobenzoic acid (1ar), 660mg of electrolyte tetraethylammonium tetrafluoroborate and 50mL of solvent ethanol into the electrolytic cell without diaphragm, and then insert Platinum sheet electrode with a current density of 13.3mA / cm 2 constant current at 50 o Stirring reaction under C;

[0060] (2) Track the reaction by thin-layer chromatography. After the reaction is completed, the solvent is removed under vacuum, and then separated by silica gel column chromatography to obtain the lactone product 3-methyl-9-chloro-6 H - Benzo[c]chroman-6-one (2ar) 55 mg, 45% yield.

[0061] 1 H NMR (400 MHz, CDCl 3 ): δ 8.34 (d, J = 1.7 Hz, 1H), 8.02-8.00 (d, J =8.6 Hz, 1H), 7.89-7.87 (d, J = 8.5 Hz, 1H), 7.75-7.73 (dd, J = 8.6 Hz, 1.9Hz, 1H), 7.17-7.15 (d, J = 7.0 Hz, 2H), 2.45 (s, 3H) ; 13 C NMR (100 MHz, CDCl 3 ): δ160.3, 151.1, 141.8, 135.0, 134.4, 133.5, 130.0, 125.9, 123.1, 122.5, 122.2, 118.0, 114.7, 21.4.

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Abstract

The invention discloses a method for electrochemically synthesizing lactones. The method uses carboxylic acids as raw materials, and directly obtains lactones with various structures through electrochemically oxidized C-H / O-H cross-coupling, such as biaryl lactones. Esters, coumarin lactones, benzofuran lactones, etc. The synthesis method has the advantages of simple process, strong stability, environmental protection, easy control and large-scale production, and the raw materials are directly oxidized into lactone products under electrochemical conditions, which is more efficient and quicker. In addition, the raw material substrate has a wide range of applications and is easy to obtain. At the same time, there is no need to add transition metal catalysts, photocatalysts or organic small molecule catalysts during the preparation process, which increases the versatility of lactone synthesis and is also conducive to improving the yield of lactone. .

Description

【Technical field】 [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for electrochemically synthesizing lactones. 【Background technique】 [0002] As a skeleton structure, lactone widely exists in natural products or medicines. Because of its high biological activity, it has been widely used in various fields such as organic synthesis, catalytic chemistry, biomedicine, and environmental governance. At present, the commonly used lactone synthesis methods mainly include esterification method and dehydrogenation method, among which the esterification method is generated by dehydration of hydroxy acid. Since strong acid is needed to catalyze oxidation during the synthesis process, many by-products will be produced, which not only pollute environment, and greatly reduces the purity of the lactone, and there are certain safety hazards in the use of strong acid; although the dehydrogenation method can synthesize lactone with higher ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B3/02C25B3/23
CPCC25B3/23
Inventor 张胜李丽君徐坤张旭王志强
Owner NANYANG NORMAL UNIV
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