Method for preparing vitamin B6 by reduction of 2-methyl-3-hydroxypyridine-4,5-dicarboxylate

A technology of hydroxypyridine and dicarboxylate, which is applied in organic chemistry and other fields, and can solve problems such as high hidden dangers in operation

Active Publication Date: 2021-04-27
杭州隆生医药技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The invention provides a method for preparing vitamin B6 by reduction of 2-methyl-3-hydroxypyridine-4,5-dicarboxylate, which adopts the method of reducing the pyridine ring under the joint action of sodium borohydride or potassium borohydride, Lewis acid and tertiary amine The above dicarboxylic acid ester does not need to do special anhydrous treatment in the whole reaction system, and the operation is safe, and the yield of vitamin B6 obtained by the preparation is high, which solves the technical problems such as large hidden dangers in the method of preparing vitamin B6 in the prior art

Method used

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  • Method for preparing vitamin B6 by reduction of 2-methyl-3-hydroxypyridine-4,5-dicarboxylate
  • Method for preparing vitamin B6 by reduction of 2-methyl-3-hydroxypyridine-4,5-dicarboxylate

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Add 150ml 2-methyltetrahydrofuran, 25.3g, 0.1mol ethyl 2-methyl-3-hydroxypyridine-4,5-dicarboxylate, 18.1g, 0.15 mol dimethylaniline, 11.34g, 0.3mol sodium borohydride, 21.6g, 0.15mol ferrous oxalate, then slowly heat up to reflux reaction for 2 hours, after the reaction is complete, cool to 10°C, add 10% ammonium chloride solution to adjust pH value to neutral, filter, distill 2-methyltetrahydrofuran, add ethanol 150ml*3 to the residue for extraction, add hydrogen chloride gas to the extraction phase to saturation, then distill ethanol to 75ml under reduced pressure, and leave the remaining solution at room temperature Crystallize for 2-3 hours, filter, wash and dry to obtain 18.91 g of off-white solid with a purity of 98.5%, which is vitamin B6. The yield was 92%.

Embodiment 2

[0032] Add 150ml tetrahydrofuran, 0.1mol, 25.3g ethyl 2-methyl-3-hydroxypyridine-4,5-dicarboxylate, 12.1g, 0.10mol dimethylaniline to a 500ml three-necked flask equipped with stirring, thermometer and condenser , 7.59g, 0.2mol sodium borohydride, 27.81g, 0.1mol ferrous sulfate, and then slowly heated to reflux for 4 hours. After the reaction, cool to 8°C, add 10% ammonium chloride solution to adjust the pH value to neutral, filter and distill off THF and water, add 150ml*3 ethanol to the residue for extraction, add hydrogen chloride gas to the extraction phase to saturation, and then depressurize Ethanol was evaporated to 75ml, and the remaining solution was left to stand at room temperature for 2-3 hours to crystallize, filtered, washed and dried to obtain 19.2g of off-white solid with a purity of 98.5%, which was vitamin B6. The yield was 93.4%.

Embodiment 3

[0034]Add 150ml of dioxane, 25.3g, 0.1mol ethyl 2-methyl-3-hydroxypyridine-4,5-dicarboxylate, 12.1g, 0.12mol Triethylamine, 9.46g, 0.25mol sodium borohydride, 15.21g, 0.12mol ferrous chloride and then slowly raise the temperature to 90°C for 3 hours. Cool to 2°C after the reaction, add 10% ammonium chloride solution to adjust the pH value to neutral, filter and distill off dioxane and water, add 150ml*3 ethanol to the residue for extraction, and add hydrogen chloride gas to the extraction phase until it is saturated. Then the ethanol was evaporated under reduced pressure to 75ml, and the remaining solution was left to stand at room temperature for crystallization for 2-3 hours, filtered, washed and dried to obtain 18.4g of off-white solid with a purity of 98.2%, which was vitamin B6. The yield was 89.5%.

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Abstract

The invention discloses a method for preparing vitamin B6 by reducing 2-methyl-3-hydroxypyridine-4,5-dicarboxylate, wherein 2-methyl-3-hydroxypyridine-4,5-dicarboxylate is dissolved in a solvent , and then sequentially add sodium borohydride or potassium borohydride, Lewis acid, tertiary amine, and then heat the reaction for 2-4 hours. pH to neutral, filter and concentrate, extract, pass through HCl gas, concentrate and stand for crystallization, filter and dry to obtain the crude product of vitamin B6. In this technical scheme, vitamin B6 is prepared by reducing 2-methyl-3-hydroxypyridine-4,5-dicarboxylate under the joint action of sodium borohydride or potassium borohydride, Lewis acid and tertiary amine. During the whole operation process, The solvent used does not need to be anhydrous, nor does it need to use high-pressure equipment, and it is carried out under mild conditions.

Description

technical field [0001] The invention relates to a method for preparing vitamin B6, in particular to a method for preparing vitamin B6 by reducing 2-methyl-3-hydroxypyridine-4,5-dicarboxylate. Background technique [0002] Vitamin B6 exists in nature in three forms: pyridoxine, pyridoxal and pyridoxamine. Under certain conditions, the three can be transformed into each other in the body. Industrially synthesized vitamin B6 is generally pyridoxine hydrochloride. At present, most industries use the oxazole method to chemically synthesize vitamin B6. [0003] There are two main types of oxazole methods for industrialized large-scale production of vitamin B6: [0004] Method 1: use 4-methyl-5-alkoxyoxazole or 4-methyl-5-alkylsiloxyoxazole and 2-alkyl-4,7-dihydro-1,3-di After Diels-Alder addition and aromatization reaction, oxheptin is then salted to obtain vitamin B6. The disadvantages of this method are: high reaction energy consumption, long reaction time, and large feed ra...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C07D213/67
CPCC07D213/67
Inventor靳磊卢杰张为群李子成刘鹏
Owner杭州隆生医药技术有限公司