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A kind of preparation method of vitamin A intermediate C20 alcohol

A technology for intermediates and vitamins, applied in the field of preparation of vitamin A intermediate C20 alcohol, which can solve the problems of high process safety risk and low utilization rate of iso-C6 alcohol raw materials, etc., to simplify the reaction route, improve the total utilization rate, and expand production effect of scale

Active Publication Date: 2020-06-12
SHANGYU NHU BIOCHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the problems of low raw material utilization rate of iso-C6 alcohol and high risk of process safety in the preparation process of C20 alcohol by using cis-C6 alcohol, the present invention provides an improved method for preparing vitamin A intermediate C20 alcohol. The method directly prepares the double Grignard reagent with iso-C6 alcohol and then reacts with C14 aldehyde, without the need for isomerization reaction to prepare and separate cis-C6 alcohol, which improves the safety of this process route and greatly improves the iso-C6 alcohol. Raw material utilization rate of C6 alcohol

Method used

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  • A kind of preparation method of vitamin A intermediate C20 alcohol
  • A kind of preparation method of vitamin A intermediate C20 alcohol
  • A kind of preparation method of vitamin A intermediate C20 alcohol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Step (1) 3-methyl-4-pentene-1-yn-3-alcohol (I) (isoC6 alcohol) reacts with ethylmagnesium bromide as Grignard reagent in an ether solvent to obtain the compound of formula (II)

[0035] 1.1) Take 10g of magnesium chips into a 1000ml four-necked flask with stirring and a thermometer, slowly add 500ml of ethyl bromide solution with a mass fraction of 10% ethyl bromide dropwise, and reflux at 35-40°C for 4 hours until the magnesium powder is completely dissolved to obtain a grid. The ether solution of ethylmagnesium bromide of Shi's reagent;

[0036] 1.2) Slowly add 20 g of compound (I) (isoC6 alcohol) dropwise to the ether solution of ethylmagnesium bromide as the Grignard reagent, and continue the reaction at 35 ° C for 2 h to convert the isoC6 alcohol into compound (II )

[0037] Step (2) Compound (II) and 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butene-1-aldehyde (III) (C14 aldehyde) reaction obtains compound (IV)

[0038] 40 g of compound (III) (C14 aldehy...

Embodiment 2

[0044]Step (1) 3-methyl-4-pentene-1-yn-3-alcohol (I) (isoC6 alcohol) reacts with ethylmagnesium bromide as Grignard reagent in an ether solvent to obtain the compound of formula (II)

[0045] 1.1) Take 10g of magnesium chips into a 1000ml four-necked flask with stirring and a thermometer, slowly add 500ml of ethyl bromide solution with a mass fraction of 10% ethyl bromide dropwise, and reflux at 35-40°C for 4 hours until the magnesium powder is completely dissolved to obtain a grid. The ether solution of ethylmagnesium bromide of Shi's reagent;

[0046] 1.2) Slowly add 20 g of compound (I) (isoC6 alcohol) dropwise to the ether solution of ethylmagnesium bromide as the Grignard reagent, and continue to incubate at 20°C for 6 hours to convert the isoC6 alcohol into compound (II )

[0047] Step (2) Compound (II) and 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butene-1-aldehyde (III) (C14 aldehyde) reaction obtains compound (IV)

[0048] 40 g of compound (III) (C14 aldehy...

Embodiment 3

[0054] Step (1) 3-methyl-4-pentene-1-yn-3-alcohol (I) (isoC6 alcohol) reacts with ethylmagnesium bromide as Grignard reagent in an ether solvent to obtain the compound of formula (II)

[0055] 1.1) Take 10g of magnesium chips into a 1000ml four-necked flask with stirring and a thermometer, slowly add 500ml of ethyl bromide solution with a mass fraction of 10% ethyl bromide dropwise, and reflux at 35-40°C for 4 hours until the magnesium powder is completely dissolved to obtain a grid. The ether solution of ethylmagnesium bromide of Shi's reagent;

[0056] 1.2) Slowly add 20 g of compound (I) (isoC6 alcohol) dropwise to the ether solution of ethylmagnesium bromide as the Grignard reagent, and continue the reaction at 35 ° C for 2 h to convert the isoC6 alcohol into compound (II )

[0057] Step (2) Compound (II) and 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butene-1-aldehyde (III) (C14 aldehyde) reaction obtains compound (IV)

[0058] 40 g of compound (III) (C14 aldehy...

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Abstract

A preparation method of a vitamin A intermediate C20 alcohol comprises the following steps: reacting a compound (I) and ethylmagnesium bromide as a Grignard reagent in an ester solvent to obtain a compound (II); reacting the compound (II) and a compound (III) to obtain a compound (IV); (3) hydrolyzing the compound (IV) under an acidic condition, and then removing the solvent to obtain a compound (V); (4) dissolving the compound (V) in an organic solvent A, performing isomerization reaction under the action of an acid catalyst, separating away an acid catalyst layer after the reaction is ended, neutralizing a product layer by using an alkaline solution, and then performing cooling crystallization and filtering to obtain high-purity 3,7-dimethyl-9-(2,6,6- trimethyl cyclohexene)-2,7-diene-4-alkyne-1,6-diol(VI).

Description

technical field [0001] The invention relates to a preparation method of dihydric alcohol, in particular to a preparation method of vitamin A intermediate C20 alcohol. Background technique [0002] 3,7-Dimethyl-9-(2,6,6-trimethylcyclohexene)-2,7-diene-4-yne-1,6-diol (referred to as C20 alcohol) is developed by Roche The C14 aldehyde + C6 alcohol is an important intermediate in the synthetic VA process route. At present, in the industrialized method, C20 alcohol is mainly prepared by the following reaction of cis six-carbon alcohol (abbreviated as cis C6 alcohol) and tetradecyl aldehyde (abbreviated as C14 aldehyde): [0003] [0004] Wherein, cis-C6 alcohol is obtained by isomerization reaction of 3-methyl-4-pentene-1-yn-3-alcohol (isoC6 alcohol,) under acidic catalysis: [0005] [0006] The yield of the cis-C6 alcohol obtained by the above-mentioned isomerization generally does not exceed 85%. Since the product must be separated by rectification, there will also be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C29/56C07C33/14
CPCC07C29/09C07C29/56C07F3/02C07C33/14
Inventor 郑兆祥何仕炜张敏周丹
Owner SHANGYU NHU BIOCHEM IND