A kind of method for realizing methylation reaction of ketone α position under electrochemical conditions

A methylation and electrochemical technology is applied in the field of realizing the methylation reaction at the α position of ketone, and the effect of cheap and easy to obtain reaction raw materials, high yield, and simple atomic economy is achieved.

Active Publication Date: 2021-05-28
GUANGXI NORMAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In recent years, with the development of photocatalysis and some multifunctional loading materials, some relatively novel and environmentally friendly synthetic routes have also been developed (ACS Sust. Chem. Eng. 2017, 5, 9683-9691; Adv. Synth. Catal. 2018, 360,3471-3476), the reaction mechanism of all the current methods is roughly similar, first methanol is oxidized to formaldehyde under the catalyst, formaldehyde molecules undergo aldol condensation dehydration with ketone under the promotion of alkali to obtain enone intermediates, enone intermediates Under the attack of nucleophilic reagents, the ketone α-position methylated product or the methylated compound containing other groups are obtained. Although there are various synthetic means of ketone α-position methylation in the prior art, using The way of electrochemical oxidation to promote the α-methylation reaction of ketones has not been reported

Method used

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  • A kind of method for realizing methylation reaction of ketone α position under electrochemical conditions
  • A kind of method for realizing methylation reaction of ketone α position under electrochemical conditions
  • A kind of method for realizing methylation reaction of ketone α position under electrochemical conditions

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Preparation and characterization of 2-methyl-3-methoxy-1-phenyl-1-propanone (2a):

[0017]

[0018] Place propiophenone (0.5mmol, 1.0equiv), cesium carbonate (1.0mmol, 2equiv) and tetrabutylammonium tetrafluoroborate (0.25mmol, 0.5equiv) in a 10mL three-neck round bottom flask equipped with a condenser , RVC (100ppi, 1cmx1cmx1.2cm) anode and platinum plate (1cmx1cm) cathode, put on an oxygen bulb and add 6mL methanol to the reaction bottle, and react at 65°C with a constant current of 10mA until the raw materials are completely consumed (monitored by thin-layer chromatography , reaction 3h), the reaction mixture was cooled to room temperature, the reaction was quenched with 30mL of water, and 30mL of ethyl acetate was added for extraction, the organic phase was separated, and the aqueous phase was extracted with 30mL of ethyl acetate, the organic phases were combined and washed with anhydrous sulfuric acid Dry over magnesium, filter, and concentrate under reduced pre...

Embodiment 2

[0022] Preparation and characterization of 2-methyl-3-methoxy-1-(4-methyl)phenyl-1-propanone (2b):

[0023]

[0024] 4-Methylpropiophenone (0.5mmol, 1.0equiv), cesium carbonate (1.0mmol, 2equiv) and tetrabutylammonium tetrafluoroborate (0.25mmol, 0.5equiv) were placed in a 10mL three-neck round bottom flask, and the flask Equipped with a condenser, RVC (100ppi, 1cmx1cmx1.2cm) anode and platinum plate (1cmx1cm) cathode, put on an oxygen balloon and add 6mL methanol to the reaction bottle, and react at 65°C with a constant current of 10mA until the raw material is completely consumed (by TLC monitoring, reaction 3h), the reaction mixture was cooled to room temperature, quenched the reaction with 30mL water, and added 30mL ethyl acetate for extraction, separated the organic phase, and then extracted the aqueous phase with 30mL ethyl acetate, combined the organic phase After drying with anhydrous magnesium sulfate, filtering, and concentrating under reduced pressure, the residu...

Embodiment 3

[0028] Preparation and characterization of 2-methyl-3-methoxy-1-(4-methoxy)phenyl-1-propanone (2c):

[0029]

[0030] 4-Methoxypropiophenone (0.5mmol, 1.0equiv), potassium carbonate (1.0mmol, 2equiv) and tetrabutylammonium tetrafluoroborate (0.25mmol, 0.5equiv) were placed in a 10mL three-neck round bottom flask, The flask is equipped with a condenser, RVC (100ppi, 1cmx1cmx1.2cm) anode and platinum plate (1cmx1cm) cathode, put on an oxygen bulb and add 6mL of methanol to the reaction flask, and react at a constant current of 10mA at 65°C until the raw materials are completely consumed ( Monitored by thin-layer chromatography, reaction 4h), the reaction mixture was cooled to room temperature, quenched the reaction with 30mL of water, and added 30mL of ethyl acetate for extraction, separated the organic phase, and then extracted the aqueous phase with 30mL of ethyl acetate, combined organic The phases were combined and dried with anhydrous magnesium sulfate, filtered, and con...

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Abstract

The invention discloses a method for realizing the α-position methylation reaction of ketones under electrochemical conditions. This method adopts an electrochemical dehydrogenation coupling strategy to realize the direct conversion of ketones and methanol to ketones. α In the methylation reaction, under mild electrochemical oxidation conditions, methanol is used as a C-1 source, and ketones and methanol are directly ketones in an oxygen atmosphere under alkaline conditions. α The methylation reaction uses the solvent methanol as the methylation reagent, which has the advantages of environmental protection, atom economy and simple steps. The reaction avoids the use of transition metal catalysts and oxidants, and the operation is simple, the yield is high, and the raw materials are easily available and clean. Environmentally friendly, well in line with the concept of modern green chemistry.

Description

technical field [0001] The invention relates to chemical synthesis, in particular to a method for realizing the α-position methylation reaction of ketones under electrochemical conditions. Background technique [0002] Methylation reactions are fundamental transformations that play a key role in the synthesis and functionalization of bioactive molecules (Chem. Rev. 2011, 111, 5215-5246). Methyl fragments exist in many popular drug compounds, which can effectively adjust the physical and biological properties of the compounds, and many important natural products and pharmaceutically active compounds contain α-methyl ketones (J.Nat.Prod.2011 , 74, 997-1002). For example, Eperisone and Tolperisone are antispasmodics (Pharmacology. 2004, 71, 150-156); Eprazinone (trade name Eftapan) is a mucolytic and can relieve bronchospasm (Fortschr. Med. 1980, 98, 871-874 ), in addition, the "profen family" containing α-methylcarboxylic acid groups such as ibuprofen, naproxen, ketoprofen a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B3/23C25B3/29C25B3/07C25B3/11
CPCC25B3/23C25B3/29
Inventor 潘永周唐海涛莫始坤蒙秀金潘英明
Owner GUANGXI NORMAL UNIV
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