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Preparation method of alpha-bromoacetophenone compound

A technology for bromoacetophenone and compound is applied in the field of preparation of α-bromoacetophenone compounds, can solve the problems of complex synthesis route, large pollution of brominating reagents and high cost, and achieves good reaction selectivity and high product quality. The effect of high yield and low synthesis cost

Active Publication Date: 2021-12-17
ZHEJIANG NORMAL UNIVERSITY
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  • Abstract
  • Description
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Problems solved by technology

[0009] 1) The acetyl group belongs to the meta-positioning group, which has a passivation effect on the benzene ring, which is not conducive to the introduction of other substituents on the benzene ring. Therefore, in order to obtain acetophenone with other different substituents on the benzene ring, it has certain difficulty;
[0010] 2)Br 2 , NBS, CuBr 2 Bromination reagents such as bromide have the characteristics of large pollution and high cost;
[0011] 3) The synthesis route of (2-bromoethynyl) benzene is relatively complicated, and some (2-bromoethynyl) benzene derivatives are very unstable, so the source of raw materials is also limited

Method used

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  • Preparation method of alpha-bromoacetophenone compound
  • Preparation method of alpha-bromoacetophenone compound

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Experimental program
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Effect test

Embodiment 1

[0047] The preparation method of the α-bromoacetophenone of present embodiment, comprises the following steps:

[0048] (1) Add ethylbenzene (3mmoL), NaBr (6.6mmoL), NaBrO 3 (3.3mmoL), 1,2-dichloroethane (3.5mL) and water (0.4mL), then install a tail gas absorption device and a reflux condenser, stir and heat to reflux, add dropwise sulfuric acid solution (4.95mmoL) and Azodiisobutyronitrile solution (0.12mmol AIBN, 1,2-dichloroethane is a solvent), after the dropwise addition is completed, continue to reflux reaction, track and detect with thin-layer chromatography, after the reaction is complete, stop heating, and drop to At room temperature, neutralize by adding saturated aqueous sodium bicarbonate solution, extract the aqueous phase with 1,2-dichloroethane, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, and recover the organic solvent by distillation under reduced pressure. Purified by silica gel column chromatography, the interme...

Embodiment 2

[0055] The difference between the preparation method of the α-bromoacetophenone compound of the present embodiment and Example 1 is:

[0056] Using 3 mmol of 1-tert-butyl-3-ethylbenzene as raw material, other steps refer to step (1) of Example 1 to obtain intermediate 1-(1,1,2-tribromoethyl)-3-tert-butyl Benzene, colorless oily substance, yield 0.92g, yield 77%.

[0057] Wherein, the chemical formula of intermediate 1-(1,1,2-tribromoethyl)-3-tert-butylbenzene is: The NMR data are as follows:

[0058] 1 H NMR (600MHz, CDCl 3 )δ7.80(t, J=2.0Hz, 1H), 7.59-7.58(m, 1H), 7.40-7.38(m, 1H), 7.32(t, J=7.8Hz, 1H), 4.67(s, 2H ),1.37(s,9H); 13 C NMR (151MHz, CDCl 3 ) δ 151.3, 140.9, 128.1, 126.7, 124.6, 124.4, 65.6, 45.7, 35.0, 31.4.

[0059] With 1mmol 1-(1,1,2-tribromoethyl)-3-tert-butylbenzene as raw material, other steps refer to step (2) of Example 1 to obtain the product 2-bromo-1-(3-tert Butylphenyl)ethanone, colorless oil, yield 173mg, yield 68%.

[0060] Wherein, the ch...

Embodiment 3

[0063] The difference between the preparation method of the α-bromoacetophenone compound of the present embodiment and Example 1 is:

[0064] With 3mmol 1-bromo-3-ethylbenzene as raw material, other steps refer to the step (1) of Example 1 to obtain intermediate 1-bromo-3-(1,1,2-tribromoethyl)benzene, without Color oil, yield 0.95g, yield 75%.

[0065] Wherein, the chemical formula of the intermediate 1-bromo-3-(1,1,2-tribromoethyl)benzene is: The NMR data are as follows:

[0066] 1 H NMR (600MHz, CDCl 3 )δ7.91(s,1H),7.67(d,J=8.0Hz,1H),7.48(d,J=7.9Hz,1H),7.26(t,J=8.0Hz,1H),4.59(s, 2H). 13 C NMR (151MHz, CDCl 3 ) δ 143.1, 132.6, 130.5, 129.7, 125.8, 122.3, 62.5, 45.2.

[0067] With 1mmol 1-bromo-3-(1,1,2-tribromoethyl)benzene as raw material, other steps refer to the step (2) of Example 1 to obtain the product 2-bromo-1-(3-bromophenyl ) ethyl ketone, white solid, yield 195mg, yield 70%.

[0068] Wherein, the chemical formula of 2-bromo-1-(3-bromophenyl)ethanone is: ...

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Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of an alpha-bromoacetophenone compound. The preparation method comprises the steps of (1) in an organic solvent, taking bromate, bromide and sulfuric acid as bromination reagents, and under the action of an initiator, carrying out free radical bromination reaction on an ethyl benzene compound to obtain a (1, 1, 2-tribromoethyl) benzene derivative; and (2) in an acidic solution, carrying out a hydrolysis reaction on the (1, 1, 2-tribromoethyl) benzene derivative to obtain the alpha-bromoacetophenone compound. According to the preparation method of the alpha-bromoacetophenone compound, the alpha-bromoacetophenone compound can be prepared by adopting a two-step method, and the process is simple; and all the raw materials are common chemicals which are cheap and easy to obtain, and the synthesis cost is low.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a preparation method of α-bromoacetophenone compounds. Background technique [0002] α-Bromoacetophenone compounds and their derivatives are important pharmaceutical and pesticide intermediates, such as: p-methoxybromoacetophenone is the key intermediate for the treatment and prevention of women's osteoporosis drug raloxifene 3-nitro-4-benzyloxy-α-bromoacetophenone compounds are the key intermediates of formoterol, an asthma drug. [0003] [0004] In the prior art, the method for preparing α-bromoacetophenone compounds mainly includes: [0005] 1) Acetophenone and Br 2 , NBS, CuBr 2 Bromination reaction of other brominating reagents (J.Heterocyclic Chem.,2020,57,1-9; Eur.J.Org.Chem.,2017,2017,781-785; Eur.J.Med.Chem.,2015 ,18-23.), which is currently the most commonly used method for preparing α-bromoacetophenones; [0006] 2) Use an oxidant to oxid...

Claims

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Application Information

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IPC IPC(8): C07C45/43C07C49/80C07C201/12C07C205/45C07C51/09C07C51/373C07C65/32C07C49/82C07B41/06
CPCC07C45/43C07C17/14C07C201/12C07C51/09C07C51/373C07C67/307C07C67/287C07B41/06C07C49/80C07C22/04C07C25/02C07C205/11C07C205/45C07C65/32C07C69/76C07C49/82C07C69/157
Inventor 肖孝辉林霞罗虹
Owner ZHEJIANG NORMAL UNIVERSITY
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