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Method for directly oxidizing benzyl-position C-H bond into ketone

A direct, benzylic technology, applied in chemical instruments and methods, preparation of quinone oxides, preparation of organic compounds, etc., can solve the problems of selective oxidation of monoketones and diketones, unstable peroxide oxidants, etc. problems, to achieve the effect of avoiding metal residues, simple operation, and high-efficiency synthesis

Active Publication Date: 2017-08-04
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Excessive unstable peroxide oxidizing agents cannot achieve selective oxidation of monoketones and diketones

Method used

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  • Method for directly oxidizing benzyl-position C-H bond into ketone
  • Method for directly oxidizing benzyl-position C-H bond into ketone
  • Method for directly oxidizing benzyl-position C-H bond into ketone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] p-Methoxyacetophenone Synthesis

[0021] Add 0.5 equivalent of NHPI to a 25 mL Schlenk reaction tube, dry in vacuum for 15 minutes, cover with an oxygen bulb, add 1 mL of acetonitrile, 1.0 equivalent of tert-butyl nitrite, and 0.5 mmol of p-ethylanisole in sequence under an oxygen atmosphere. Put a polytetrafluoro stopper on the tube and put it in an oil bath, and react at 80°C for 24h. After the reaction was completed, the solvent was concentrated under reduced pressure to remove acetonitrile, and separated by column chromatography, and the eluent was petroleum ether / ethyl acetate (v:v=20:1) to obtain p-methoxyacetophenone. Yield 83%, pale yellow solid; 1 H NMR (CDCl 3 ,400MHz): δ7.92(d,J=9.2Hz,2H),6.92(d,J=8.8Hz,2H),3.85(s,3H),2.54(s,3H); 13 C NMR (CDCl 3 ,100MHz): δ196.7,163.4,130.5,130.3,113.6,55.4,26.3.

Embodiment 2

[0023] 4-Acetoxyacetophenone Synthesis

[0024] Add 1.0 equivalent of NHPI to a 25 mL Schlenk reaction tube, dry in vacuum for 15 minutes, cover with an oxygen bulb, add 1 mL of acetonitrile, 2.0 equivalents of tert-butyl nitrite, and 0.5 mmol of p-acetoxyethylbenzene in an oxygen atmosphere. Put a polytetrafluoro stopper on the reaction tube and put it in an oil bath, and react at 80°C for 24h. After the reaction was completed, the solvent was concentrated under reduced pressure to remove acetonitrile, and separated by column chromatography, the eluent was petroleum ether / ethyl acetate (v:v=10:1) to obtain 4-acetoxyacetophenone. Yield 72%, white solid; 1 H NMR (CDCl 3,400MHz): δ7.96(d,J=6.8Hz,2H),7.16(d,J=6.8Hz,2H),2.56(s,3H),2.30(s,3H); 13 C NMR (CDCl 3 ,100MHz): δ196.8, 168.8, 154.2, 134.5, 129.8, 121.7, 26.5, 21.0.

Embodiment 3

[0026] p-Fluoroacetophenone Synthesis

[0027] Add 0.5 equivalent of NHPI to a 25 mL Schlenk reaction tube, dry in vacuum for 15 minutes, cover with an oxygen bulb, add 1 mL of acetonitrile, 1.0 equivalent of tert-butyl nitrite, and 0.5 mmol of p-fluoroethylbenzene in the reaction tube After adding a polytetrafluoro stopper, put it into an oil bath, and react at 80°C for 24h. After the reaction was completed, the solvent was concentrated under reduced pressure to remove acetonitrile, and separated by column chromatography, and the eluent was petroleum ether / ethyl acetate (v:v=50:1) to obtain p-fluoroacetophenone. Yield 78%, pale yellow oil; 1 HNMR (CDCl 3 ,400MHz):δ7.96(dd,J=8.2Hz,5.4Hz,2H),7.10(t,J=8.4Hz,2H),2.56(s,3H); 13 C NMR (CDCl 3 ,100MHz): δ196.4,166.9,164.4,133.5(d,J=3.0Hz),130.8(d,J=9.8Hz),115.6(d,J=21.9Hz),26.4.

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Abstract

The invention discloses a method for directly oxidizing a benzyl-position C-H bond into ketone, wherein aryl ethyl compounds are catalyzed and oxidized by nitrite ester; a synergistic catalytic system of free radical initiator and nitrite ester is adopted, and a catalytic system of non-metallic catalyst and oxygen is adopted, the oxidization of the C-H bond of a free radical-activated aryl side chain is simple in operation; after completing the reaction, petroleum ether / ethyl acetate at a volume ratio of (50-1):1 is used as an eluent; column chromatography separation is performed to obtain a target product. The catalytic system in the invention uses oxygen as an oxygen source and has high atomic economy; the invention is a non-metallic catalytic system and provides a novel method for avoid metal residues in synthetic drugs; for diethyl aromatic hydrocarbon, the method provided by the invention can be adopted to selectively oxidize diethyl aromatic hydrocarbon into monoketone and diketone; the method of the invention can be adopted to efficiently synthesize tranquillizer lenperone, so that a novel method for synthesizing lenperone is provided.

Description

technical field [0001] The invention belongs to the technical field of catalyzing aryl ethyl to synthesize ketone compounds, in particular to a method for directly oxidizing aryl side chain C-H bonds to form ketones. Background technique [0002] Acyl groups are ubiquitous in organic synthesis intermediates and pharmaceutical compounds, so the direct oxidation of aryl side chain C-H bonds to ketones has been widely used in chemical industry, especially in pharmaceutical fields. The traditional method of directly oxidizing the C-H bond of the aryl side chain to ketone is to make potassium permanganate or potassium dichromate under harsh conditions, and there are many by-products, and the oxidation cannot be selectively controlled when there are two side chains. . In recent years, the use of transition metals as catalysts has been developed. Due to the high cost of transition metal complex oxidants and metal residues, its large-scale application in industry and pharmaceutical...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/36C07C49/84C07C49/807C07C49/788C07C49/76C07C49/80C07C49/786C07C49/637C07C49/633C07C49/784C07C67/29C07C69/157C07C201/12C07C205/45C07C253/30C07C255/56C07D213/50C07D333/22C07D211/32C07C46/02C07C50/10
CPCC07C45/36C07C46/02C07C67/29C07C201/12C07C253/30C07D211/32C07D213/50C07D333/22C07C49/84C07C49/807C07C49/788C07C49/76C07C49/80C07C49/786C07C49/637C07C49/633C07C49/784C07C69/157C07C205/45C07C255/56C07C50/10
Inventor 康彦彪刘杰
Owner UNIV OF SCI & TECH OF CHINA
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