Method for preparing intermediate of vitamin A, namely tetradecanal

A technology of cyclic citral and C-14, which is applied in the field of preparation of vitamin A intermediate tetradecanal, can solve the problems of difficult industrial production, expensive methyl iodide, etc., and achieves low cost, easy to obtain raw materials, and simple process route Effect

Inactive Publication Date: 2011-09-21
SHAOXING UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Above-mentioned two kinds of methods all have certain shortcoming, and A method needs greatly excess methyl chloroacetate and alkali; Applied to industrial production

Method used

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  • Method for preparing intermediate of vitamin A, namely tetradecanal
  • Method for preparing intermediate of vitamin A, namely tetradecanal
  • Method for preparing intermediate of vitamin A, namely tetradecanal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Example 1: Preparation of β-cyclic citral (V)

[0038] Dilute 3g KOH with 600ml methanol and add it to a 2500ml three-necked flask. Under mechanical stirring at room temperature, 304g (2mol) α-cyclic citral is added dropwise. After the water bath is kept for about 2 hours, the dripping is completed, and the stirring is continued for about 1 hour. The gas chromatography tracks the completion of the reaction, and then 12 g of concentrated hydrochloric acid is dripped to terminate the reaction. The solvent is recovered, the residue is distilled under reduced pressure, and 255 g of the 60-63°C / 1mmHg fraction is collected, which is a colorless and transparent liquid with a gas content of 98.5% and a yield of 83.9%.

[0039] Product structure verification:

[0040]

[0041] GC-MS (m / e): 152, 137 (100%), 123, 109, 95, 91, 81, 67, 55, 43, 41;

[0042] IR(ν / cm -1 ): 1672(-CHO), 1612;

[0043] 1 HNMR(δ, ppm, 400MHz, CDCl 3 ): 1.19 (s, 6H, C8-H, C9-H), 1.43-1.46 (m, 2H, C6-H), 1.60-1.66 (...

Embodiment 2

[0045] Example 2: Preparation of C-14 enol ether (VII)

[0046] Add 12.3 g of potassium tert-butoxide (0.11 mole) and 50 ml of a mixture of 8:1 (volume ratio) of tetrahydrofuran and dimethyl sulfoxide into a 250ml three-necked flask protected by nitrogen. Add 22.2 g of C-4 phosphonate (VI) (0.1 mol) dropwise, keep the temperature at -30~-25℃ for about half an hour and finish the dripping, continue to keep warm and stir for about 1 hour to make the carbanion dissociation reaction sufficient, and then keep- Add 15.2 g of β-cyclic citral (V) (0.1 mol, prepared in Example 1) dropwise at 30~-25°C. The addition is completed in about 1 hour, and the heat preservation and stirring are continued for about half an hour. The gas chromatography traces the end of the reaction and adds 50 Stir 100 ml of water and 100 ml of ether for 10 minutes, separate the layers, wash the ether layer with 5% sodium chloride aqueous solution 3 times (25 ml each time), dry the organic layer with magnesium sulf...

Embodiment 3

[0053] Example 3: Preparation of C-14 aldehyde (III) by hydrolysis of C-14 enol ether (VII)

[0054] Add 11.0 g (0.05 mol) of C-14 enol ether (VII) prepared in Example 2, 100 g of tetrahydrofuran and 1.1 g of p-toluenesulfonic acid into a 250 ml three-necked flask under nitrogen protection, stir well and add dropwise 22g of water, stirred for one day at 20~25℃, gas chromatography tracking the reaction is basically completed, add 2g of sodium bicarbonate and 20ml of water to make a solution to neutralize, water pump depressurize tetrahydrofuran, then add 100ml of cyclohexane The organic layer was washed with 30 ml of water, dried over anhydrous magnesium sulfate, and the solvent was recovered under reduced pressure to obtain 10.2 g of crude C-14 aldehyde (III) with a gas content of 77%. Add 10.5 g of sodium bisulfite to dissolve in 80 ml of water solution, protected by nitrogen, stir under magnetic stirring at 10-20°C for 20 minutes, the organic matter basically disappeared; add 2...

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Abstract

The invention provides a method for preparing an intermediate of vitamin A, namely C14-aldehyde, and an intermediate of the C14-aldehyde, namely C14 enol ether, which comprises the following steps of: (1) under the protection of inert gas, performing rearrangement dissociation reaction on C4 phosphonate at the temperature of between -40 and 30DEG C in the presence of alkali in an ether solvent ora dipolar aprotic solvent; (2) adding beta-cyclocitral, and performing Wittig-Homer condensation reaction at the temperature of between -40 and 30DEG C in the presence of alkali in the ether solvent or the dipolar aprotic solvent to obtain the C14 enol ether; and (3) under the protection of inert gas, mixing the C14 enol ether, an acid catalyst, water and a homogenous phase solvent, and performing hydrolysis reaction at the temperature of between 10 and 35DEG C with stirring to obtain the C14-aldehyde. The method has the advantages of simple process, readily available raw materials and low cost, and has great industrial value.

Description

Technical field [0001] The invention relates to an important intermediate of vitamin A 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butene-1-al (2 -methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butenal) synthesis method. Background technique [0002] Vitamin A and its derivatives are an important class of medicines used to treat night blindness, xerophthalmia, corneal softening, and dry skin; it has a promoting effect on human growth and development, and can enhance the resistance to diseases; at the same time, vitamin A It is also an important feed additive. 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butene-1-al (2-methyl-4-(2,6,6 -trimethyl-1-cyclohexen-1-yl)-2-butenal, hereinafter referred to as fourteen carbon aldehyde or C-14 aldehyde) is a key intermediate for the synthesis of vitamin A. For example, in 1947, O.Isler and others of Roche, Switzerland In the developed C14+C6 route, vitamin A acetate is prepared from C-14 aldehydes through Grignard reaction, hydr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/162C07C41/30C07C47/225C07C45/42C07C45/85
Inventor 沈润溥宋小华虞国棋孙雄生劳学军吴春雷胡六江刘泺
Owner SHAOXING UNIVERSITY
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