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A kind of preparation method of 2,5-dialkoxy dihydrofuran compound

A dialkoxydihydrofuran and compound technology, which is applied in the field of preparation of 2,5-dialkoxydihydrofuran compounds, can solve the problems of low product yield, toxic solvent benzene, and low utilization rate of furan, etc. , to achieve the effect of simple reaction method, low production cost and convenient operation

Active Publication Date: 2017-01-25
JIANGSU QINGQUAN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The liquid bromine used in this method has extremely strong toxicity and corrosiveness, and the solvent benzene is poisonous, which is the first class carcinogen of IARC; the utilization rate of furan in this method is not high, and the product yield is low

Method used

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  • A kind of preparation method of 2,5-dialkoxy dihydrofuran compound
  • A kind of preparation method of 2,5-dialkoxy dihydrofuran compound
  • A kind of preparation method of 2,5-dialkoxy dihydrofuran compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 60g of furan, 110g of sodium carbonate, 2g of phase-transfer catalyst methyltriethylammonium chloride, and 300g of methanol are put into the reactor, stirred, and when the temperature is lowered to -5°C to 5°C by opening a low-temperature constant temperature tank, 80g of chlorine gas is fed and kept at the Reaction temperature, reaction ends after reaction 10h. Remove residual chlorine in the reaction solution under reduced pressure, let it stand (making solid-liquid layering), filter (remove solid phase transfer catalyst and salts), add an appropriate amount of anhydrous sodium sulfate to the reaction solution after drying, and let it stand for a period of time After suction filtration (to remove sodium sulfate), the filtrate was distilled under reduced pressure to obtain 97.6 g of the product 2,5-dimethoxydihydrofuran with a yield of 85.3%.

Embodiment 2

[0027] 73g of 2-methylfuran, 170g of sodium bicarbonate, a total of 2g of methyl triethylammonium chloride and tetraethylphosphine hydroxide (mass ratio of 1:1) and 350g of methanol were added to the reactor, and stirred , when the temperature is lowered to -5°C to 5°C by opening a low-temperature thermostat, pass 80 g of chlorine gas and keep the reaction temperature, and the reaction ends after 10 hours of reaction. The post-treatment process was the same as in Example 1, and 107.3 g of the product 2-methyl-2,5-dimethoxydihydrofuran was obtained with a yield of 83.7%.

Embodiment 3

[0029] Put 85g of 2,5-dimethylfuran, 160g of pyridine, 2g of phase transfer catalyst dodecyltrimethylammonium chloride, and 400g of ethanol into the reactor, stir, and turn on the low-temperature thermostat to cool down to -5°C~5°C When, logical chlorine gas 80g and keep this reaction temperature, after reaction 10h, reaction finishes. The post-treatment process was the same as in Example 1, and 130.6 g of the product 2,5-dimethyl-2,5-diethoxydihydrofuran was obtained with a yield of 79.3%.

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Abstract

The invention provides a preparation method of a 2,5-dialkoxyl dihydrofuran compound. The preparation method comprises the following steps: adding a furan compound shown by a formula I, alkyl alcohol shown by a formula III and an acid-binding agent into a reactor, stirring to react with chlorine, keeping the reaction temperature to be (-25)-25 DEG C, and reacting to obtain a 2,5-dialkoxyl dihydrofuran compound shown by a formula II, wherein in the formulas, R1, R2, R3 and R4 are independent hydrogen, halogen and C1-C5 alkyl, and R1 is a C1-C12 alkyl. The method provided by the invention is less in investment, low in energy consumption and high in efficiency; the reaction method is simple, and the operation is convenient and easy to implement; the raw materials are low in price, easy to obtain, and low in production cost; a byproduct is salt and can meet requirements on environmental protection; and the preparation method is suitable for performing industrial large-scale production of the 2,5-dialkoxyl dihydrofuran compound. Particularly, when a phase transfer catalyst is added into the method provided by the invention, the method also has the advantage that the yield of a target product is obviously improved.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of 2,5-dialkoxydihydrofuran compounds. Background technique [0002] 2,5-dialkoxydihydrofuran compounds are a class of important pharmaceutical intermediates and spice intermediates. For example, 2,5-dimethoxydihydrofuran is an intermediate in the synthesis of anticholinergic drugs atropine sulfate and anisodamine hydrobromide. It can be hydrolyzed and hydrogenated with hydrochloric acid to prepare the important fine petrochemical intermediate succinaldehyde, and it can also be catalytically hydrogenated to obtain 2,5-dimethoxytetrahydrofuran. For example, 2-methyl-2,5-dimethoxydihydrofuran is an indispensable raw material for blending flavors and fragrances, and is widely used in seafood and seafood flavors. [0003] Among the 2,5-dialkoxydihydrofuran compounds, there are two typical synthesis techniques of 2,5-dimethoxydihydrofuran as follows. 1. Electro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D307/32
CPCC07D307/32
Inventor 朱骥泮伟平张浩徐威田国雄周泽泽董亮
Owner JIANGSU QINGQUAN CHEM CO LTD
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