Ether bond dissociation method of phenylalkyl ether

A technology of phenyl alkyl ether and ether bond, which is applied in the field of intermediate synthesis of pharmaceuticals and chemical raw materials, and can solve the problem of severe exothermic reaction between iodine and aluminum powder, high price of aluminum triiodide, difficulty in using aluminum triiodide, etc. problems, to achieve the effect of low price, wide application range and easy operation

Active Publication Date: 2018-09-11
JINGCHU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Node et al. also studied the cracking of ether bonds in acetonitrile by the aluminum trichloride-sodium iodide system (Chemical & Pharmaceutical Bulletin 1983, 31, 4178-4180), but these methods cracked arylalkyl groups containing acid-labile functional groups Ether, there are still difficulties
[0004] Aluminum triiodide is also commonly used a kind of ether bond splitting reagent, in order to solve the ether bond cracking that contains the aryl alkyl ether of acid labile functional group, CN106278825A, CN106866377A and CN107473916A disclose a kind of using aluminum triiodide-pyridine, A method for cleaving ether bonds with acid scavengers such as carbodiimide, inorganic bases, and metal oxides, but aluminum triiodide is expensive, inconvenient to store and use, and although aluminum triiodide can be prepared in situ, the in situ preparation Combustible aluminum powder is needed in the process, and the reaction between iodine and aluminum powder is exothermic, and excessive aluminum powder increases the difficulty of post-processing
It can be seen that it is difficult to use aluminum triiodide in industrial production

Method used

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  • Ether bond dissociation method of phenylalkyl ether
  • Ether bond dissociation method of phenylalkyl ether
  • Ether bond dissociation method of phenylalkyl ether

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1 (eugenol demethylation)

[0028]

[0029] Acetonitrile (40ml) was added to a 100ml round bottom flask, followed by aluminum trichloride (0.759g, 5.7mmol, 1.1eq), potassium iodide (0.948g, 5.7mmol, 1.1eq), DIC (0.378g, 2.9mmol, 0.6eq) and eugenol (0.844g, 5.1mmol), heated to 80°C, stopped stirring after 18 hours of reaction, cooled to room temperature, added 2mol / L dilute hydrochloric acid (10ml) into the round bottom flask for acidification, and dilute with ethyl acetate Esters (50ml×3) were extracted, the organic phases were combined, washed with a saturated aqueous solution of sodium thiosulfate (10ml), then washed with saturated brine (10ml), dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated to dryness with a rotary evaporator , the residue was purified by flash column chromatography (eluent is petroleum ether / ethyl acetate=4:1, volume ratio) to obtain 0.504g 4-allyl catechol (off-white waxy solid, yield 65%).

[0030...

Embodiment 2

[0032] Embodiment 2 (eugenol demethylation)

[0033]

[0034] Acetonitrile (40ml) was added to a 100ml round bottom flask, followed by aluminum trichloride (0.738g, 5.5mmol, 1.1eq), sodium iodide (0.828g, 5.5mmol, 1.1eq), DIC (0.377g, 2.9 mmol, 0.6eq) and eugenol (0.824g, 5.0mmol), heated to 80°C, stopped stirring after 18 hours of reaction, and added 2mol / L dilute hydrochloric acid (10ml) to the round-bottomed flask to acidify after cooling to room temperature. Extract with ethyl acetate (50ml×3), combine the organic phases, wash with a saturated aqueous solution of sodium thiosulfate (10ml), then wash with saturated brine (10ml), dry over anhydrous magnesium sulfate, filter, and use a rotary evaporator for the filtrate Evaporated to dryness, the residue was purified by flash column chromatography (eluent: petroleum ether / ethyl acetate=4:1, volume ratio) to obtain 0.418g of 4-allyl catechol (off-white waxy solid, Yield 55%).

[0035] R f =0.44 (petroleum ether / ethyl ace...

Embodiment 3

[0036] Embodiment 3 (eugenol demethylation)

[0037]Acetonitrile (40ml) was added to a 100ml round bottom flask, followed by aluminum trichloride (0.770g, 5.7mmol, 1.1eq), potassium iodide (1.742g, 10.4mmol, 2eq), DIC (0.393g, 3.1mmol, 0.6 eq) and eugenol (0.863g, 5.2mmol), heated to 80°C, stopped stirring after 18 hours of reaction, cooled to room temperature, added 2mol / L dilute hydrochloric acid (10ml) to the round bottom flask for acidification, and used ethyl acetate (50ml×3) extraction, combined organic phases, first washed with saturated aqueous sodium thiosulfate (10ml), then washed with saturated brine (10ml), dried over anhydrous magnesium sulfate, filtered, and the filtrate was evaporated to dryness with a rotary evaporator, The residue was purified by flash column chromatography (eluent: petroleum ether / ethyl acetate=4:1, volume ratio) to obtain 0.643g of 4-allyl catechol (off-white waxy solid, yield 81 %).

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Abstract

The invention discloses an ether bond dissociation method of phenylalkyl ether. The ether bond dissociation method of phenylalkyl ether includes the following steps that in organic solvent, in the presence of aluminium trihalogen, metal iodide and acid scavenging agents, phenylalkyl ether is subjected to an ether bond dissociation reaction at -20 DEG C to reflux temperature to generate phenol andderivatives thereof. The ether bond dissociation method of phenylalkyl ether is mild in condition, convenient to operate, high in yield and wide in phenylalkyl ether applicable range.

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 cracking ether bonds of phenyl alkyl ethers. Background technique [0002] The ether bond cleavage of aryl alkyl ether is a common and important functional group transformation in organic synthesis, commonly used hydrobromic acid, boron tribromide, boron trichloride, aluminum trichloride, aluminum tribromide, triiodide It can be realized by Bronsted acid or Lewis acid such as aluminum chloride and pyridine hydrochloride. For aryl alkyl ethers containing acid-labile functional groups, it is not suitable to use Bronsted acid or Lewis acid alone, because the former will cause side reactions, while the latter will generate hydrogen halides with phenolic hydroxyl groups, which will cause side reactions. Such as the demethylation reaction of eugenol (4-allyl-2-methoxyphenol), using boron tribromide (Europeann Journal ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/00C07C39/19C07C39/24C07C45/65C07C49/825
CPCC07C37/00C07C45/65C07C39/19C07C39/24C07C49/825
Inventor 桑大永涂小东田娟
Owner JINGCHU UNIV OF TECH
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