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A kind of ether bond breaking method of o-hydroxyphenyl alkyl ether

A technology of o-hydroxyphenyl alkyl ether and hydroxyphenyl alkyl ether, which is applied in the field of intermediate synthesis of medicines and chemical raw materials, can solve the problems of affecting yield, low yield of eugenol demethylation reaction, etc. Wide application range and high catalytic activity

Active Publication Date: 2019-01-11
JINGCHU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To this end, Arifin et al. developed the AlCl 3 -DMS method (Indon.J.Chem.2015,15,77), but the yield for eugenol demethylation is still very low (around 30%)
In addition, AlCl 3 - Tertiary amines can be used to remove methyl groups, but are not suitable for removing ethyl groups and other sterically hindered alkyl groups (J.Org.Chem.1962, 27, 2037), which will significantly affect the yield

Method used

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  • A kind of ether bond breaking method of o-hydroxyphenyl alkyl ether
  • A kind of ether bond breaking method of o-hydroxyphenyl alkyl ether
  • A kind of ether bond breaking method of o-hydroxyphenyl alkyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1 (demethylation of eugenol)

[0031]

[0032] Iodine (12.727g), aluminum powder (1.902g) and acetonitrile (100ml) were respectively added to a 250ml eggplant-shaped flask, heated to reflux, and stirred for 2 hours until the purple-red color of iodine disappeared. Pyridine (12.183 g) and eugenol (4.919 g) were further added, and the reaction was continued for 18 hours. The stirring was stopped, and after cooling to room temperature, 2 mol / L dilute hydrochloric acid (50 ml) was added to the reaction solution for acidification, and the mixture was extracted with ethyl acetate (50 ml×4). The organic phases were combined and dried over anhydrous sodium sulfate. Filtration, the filtrate was evaporated to dryness with a rotary evaporator, and the residue was purified by flash column chromatography (mobile phase: ethyl acetate: petroleum ether=1:4, volume ratio) to obtain 4-allylcatechol (white solid) , 4.910 g, 99% yield).

[0033] 1H NMR(400MHz, CDCl3)δ6.80(d,J...

Embodiment 2

[0035] Example 2 (demethylation of eugenol)

[0036]

[0037] Iodine (2.098g), aluminum powder (0.362g) and acetonitrile (50ml) were respectively added to a 100ml eggplant-shaped flask, heated to reflux, and stirred for 2 hours until the purple-red color of iodine disappeared. Further DMAP (2.750 g) and eugenol (0.825 g) were added and the reaction continued for 18 hours. The stirring was stopped, and after cooling to room temperature, 2 mol / L dilute hydrochloric acid (10 ml) was added to the reaction solution for acidification, and the mixture was extracted with ethyl acetate (50 ml×3). The organic phases were combined and dried over anhydrous sodium sulfate. Filtration, the filtrate was evaporated to dryness with a rotary evaporator, and the residue was purified by flash column chromatography (mobile phase: ethyl acetate: petroleum ether=1:4, volume ratio) to obtain 4-allylcatechol (white solid) , 0.362 g, 48% yield), and recovered starting material (0.202 g).

Embodiment 3

[0038] Example 3 (demethylation of eugenol)

[0039]

[0040]Add iodine (2.107g), aluminum powder (0.409g) and acetonitrile (50ml) respectively to a 100ml eggplant-shaped bottle, heat to reflux, and stir for 2 hours until the purple color of iodine disappears. Further 2,6-lutidine (2.750 g) and eugenol (0.823 g) were added, and the reaction was continued for 18 hours. Stop stirring, cool to room temperature, add 2mol / L dilute hydrochloric acid (10ml) to the reaction solution to acidify, and extract with ethyl acetate (50ml×3). The organic phases were combined and dried over anhydrous sodium sulfate. Filtration, the filtrate was evaporated to dryness with a rotary evaporator, and the residue was purified by flash column chromatography (mobile phase was ethyl acetate:petroleum ether=1:4, volume ratio) to obtain 4-allyl catechol (white solid , 0.692g, yield 92%).

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Abstract

The invention discloses an ether bond rupturing method for ortho-hydroxyl phenyl alkyl ether. The method comprises the following steps that in a solvent, an ether bond rupturing reaction occurs to ortho-hydroxyl aryl alky ether at the temperature ranging from minus 20 DEG C to the catalyst reflux temperature under the existence of alkali and a catalyst aluminum triiodide, and catechol and derivatives thereof are generated. The method is simple, reaction conditions are simple, and operation is easy; besides, the yield is high, and the applicable ortho-hydroxyl phenyl alkyl ether range is wide.

Description

technical field [0001] The invention relates to the technical field of intermediate synthesis of medicines and chemical raw materials, in particular to a method for cleaving ether bonds of o-hydroxyphenyl alkyl ethers. Background technique [0002] Substituted catechols are common intermediates in pharmaceuticals and chemical raw materials, such as hydroxytyrosol (J.Med.Chem.2015, 58, 9089), protocatechuic acid (CN 104072362) and the like. Removal of alkyl groups through ether bond cleavage reaction of o-hydroxyphenyl alkyl ether is a common synthetic method for preparing catechol. Cleavage of the ether bond of o-hydroxyphenyl alkyl ether can be carried out under the catalysis of Bronsted acid or Lewis acid. Commonly used Bronsted acids are HCl, HBr, HI, pyridine hydrochloride (such as Org.Proc.Res.Dev.2004,8,670) and the like. Commonly used Lewis acid BBr 3 (CN 104072362) and LiCl-DMF (Bioorg. Med. Chem. Lett. 2011, 21, 2659) and the like. These methods are cumbersome, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/055C07C39/18C07C39/21C07C45/64C07C47/565C07C39/08C07C253/30C07C255/53C07C51/367C07C65/03C07C49/825C07C201/12C07C205/44
CPCC07C37/055C07C45/64C07C51/367C07C201/12C07C253/30C07C39/18C07C39/21C07C47/565C07C39/08C07C255/53C07C65/03C07C49/825C07C205/44
Inventor 桑大永田娟
Owner JINGCHU UNIV OF TECH
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