A kind of preparation method of 5-benzyloxy-4-oxo-4h-pyran-2-carboxylic acid

A technology of benzyloxy and oxo, which is applied in the field of preparation of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid, which can solve the problems of high waste water content, low product purity, and the cost of separated products High-level problems, to achieve the effect of easy separation and cost-saving separation

Active Publication Date: 2020-04-21
CHONGQING TIANYI HENGHUA TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] For the above-mentioned problems in the prior art, the present invention proposes a kind of preparation method of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid, and the present invention solves the preparation method of 5-benzyl Oxygen-4-oxo-4H-pyran-2-carboxylic acid wastewater has a lot of content, high cost of separated products, and technical problems of low product purity

Method used

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  • A kind of preparation method of 5-benzyloxy-4-oxo-4h-pyran-2-carboxylic acid

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Embodiment 1

[0019] A preparation method of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid, first 90g of kojic acid is added to a 2000ml single-necked flask, then 660ml of methanol is added to dissolve the kojic acid, and then The 40% alkali solution of 80g benzyl chloride and 63ml, heat up and reflux reaction 16 hours to obtain reaction solution; Reaction solution is carried out decompression distillation, just stops distillation until solvent is evaporated to dryness, then cools to normal temperature; Add 60ml methyl alcohol and 180ml water in the substance, stir, wash, filter, the solid obtained is dried, and the solid that obtains 103g light yellow is intermediate; 103g intermediate is joined in the reactor, then adds 2000ml water, will Lower the temperature to 0°C, add sodium periodate, control the temperature at not higher than 5°C, add 40ml of water dropwise after the addition, stir for 5 minutes, then raise the temperature to 12°C, stir for 2.5 hours to obtain the reaction solution; ...

Embodiment 2

[0021] A preparation method of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid, first 90g of kojic acid is added to a 2000ml single-necked flask, then 660ml of methanol is added to dissolve the kojic acid, and then The 40% alkali solution of 88g benzyl chloride and 63ml, heats up and refluxes and reacts for 17 hours to obtain reaction solution; Reaction solution is carried out vacuum distillation, just stops distillation until solvent is evaporated to dryness, then cools to normal temperature; Add 60ml methyl alcohol and 240ml water in the substance, stir, wash, filter, the solid obtained is dried, and the solid that obtains 116g light yellow is intermediate; 116g intermediate is joined in the reactor, then adds 2000ml water, will Lower the temperature to -5°C, add sodium periodate, and control the temperature at no higher than 5°C. After the addition, add 40ml of water dropwise, stir for 10 minutes, then raise the temperature to 17°C, and stir for 3 hours to obtain a reaction sol...

Embodiment 3

[0023] A preparation method of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid, first 90g of kojic acid is added to a 2000ml single-necked flask, then 660ml of methanol is added to dissolve the kojic acid, and then The 40% alkali solution of 96g benzyl chloride and 63ml, heat up and reflux reaction to obtain reaction solution for 18 hours; The reaction solution is subjected to vacuum distillation, until the solvent is evaporated to dryness and just stop distillation, then cooled to normal temperature; Add 60ml methyl alcohol and 300ml water in the substance, stir, wash, filter, the solid that obtains is dried, and the solid that obtains 116g light yellow is intermediate; 116g intermediate is joined in the reactor, then adds 2000ml water, will Lower the temperature to -10°C, add sodium periodate, and control the temperature at no higher than 5°C. After the addition, add 40ml of water dropwise, stir for 15 minutes, then raise the temperature to 22°C, and stir for 3.5 hours to obtain...

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Abstract

The present invention discloses a 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid preparation method comprising the following steps: adding kojic acid, benzyl chloride and methanol benzyl chloride into a reaction vessel, and heating for reflux reaction for 16 to 18 hours; distilling under reduced pressure, evaporating the solvent to dryness, and cooling to room temperature; adding methanol and water, stirring, washing, filtering and drying to obtain an intermediate; and adding the intermediate and water into the reaction vessel, reducing the temperature to 0 DEG C to -10 DEG C, adding sodium periodate, controlling the temperature to be not higher than 5 DEG C, then adding dropwise a proper amount of water, stirring for 5-15 minutes, heating to 12 DEG C-22 DEG C, stirring for reaction for 2.5 to 3.5 hours, extracting with ethyl acetate, layering, drying, filtering and drying to obtain white solid 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid. The new 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid preparation method is provided, does not produce large amounts of chromium-containing waste water, prevents severe environmental pollution, and can achieve industrial production.

Description

technical field [0001] The invention relates to a preparation method of 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid. Background technique [0002] At present, 5-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid is an important intermediate in chemical synthesis and pharmaceutical synthesis, and now the production of 5-benzyloxy-4-oxo-4H-pyran The method of furan-2-carboxylic acid is mainly to connect a benzyl group on the oxygen double bond of kojic acid, and then oxidize it with Jones reagent to obtain the product 5-benzyloxy-4-oxo-4H-pyran-2-carboxylate Acid, the oxidizing agent that this method adopts is Jones reagent, itself contains chromium trioxide in Jones reagent, and whole reaction will generate a large amount of waste water at last, contains chromium in waste water, and chromium is heavy metal, and chromium can not only cause very serious pollution to environmental soil, And chromium is also a strong mutagen, which can induce cancer and cause deformity. Contents of t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D309/40
CPCC07D309/40
Inventor 郑伟唐勇
Owner CHONGQING TIANYI HENGHUA TECH CO LTD
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