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Method for preparing 4-acetoxy-2-methyl-2-butenal

A technology of acetoxy and crotonaldehyde, which is applied in the field of organic chemistry, can solve the problems of catalyst TEMPO not being recovered and solvent DMF being difficult to recover, etc., and achieve the effects of avoiding pollution problems, saving raw material costs, and saving environmental protection costs

Active Publication Date: 2013-04-03
GUANGZHOU LEADER BIO TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] In the method for preparing 4-acetoxy-2-methyl-2-butenal by chloroester, some will use solvent DMF and catalyst TEMPO, but solvent DMF is difficult to recover, and will be discharged into the environment in the form of sewage at last Among them, the expensive catalyst TEMPO is not recycled

Method used

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  • Method for preparing 4-acetoxy-2-methyl-2-butenal
  • Method for preparing 4-acetoxy-2-methyl-2-butenal

Examples

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Embodiment 1

[0050] Dissolve 6.8g of isoprene (0.1mol) in a mixture of 12.0g of acetic acid and 10.2g of acetic anhydride, stir, cool to 15°C, mix tert-butyl hypochlorite with the amount of isoprene and other substances (14.0g, 77%, 0.1mol) was slowly added dropwise and kept at a constant temperature. After the dropwise addition was completed, after detecting that there was no peroxide with starch potassium iodide test paper, 1.7g of p-toluenesulfonic acid (0.01mol) was added and the temperature was raised to After 10 hours of reaction at 60°C, the acetic acid solution containing tert-butanol was recovered by distillation under reduced pressure (can be separated and recovered by rectification). % sodium bicarbonate washed to neutrality, concentrated under reduced pressure, and finally under the pressure of 5mmHg, distilled to obtain chloroester (1-acetoxy-4-chloro-3-methyl-2-butene) 14.0g, Content 93%, yield 80.1%.

[0051] Add 18.1g chlorate (93%, 0.1mol) to 50mL acetone, add 12.6g potas...

Embodiment 2

[0055] Dissolve 68g of isoprene (1mol) in a mixed solution of 120g of acetic acid and 102g of acetic anhydride, stir, cool to 15°C, mix tert-butyl hypochlorite (140.3g, 77%, 1mol) was slowly added dropwise and kept constant temperature. After the dropwise addition was completed, use starch potassium iodide test paper to detect the absence of peroxide, then add 17g of p-toluenesulfonic acid (0.1mol), raise the temperature to 60°C, and react for 10 hours Finally, tert-butanol and acetic acid were recovered by distillation under reduced pressure (separation and recovery by rectification), 200g of ice water was added, and the product chlorine ester was extracted from ice water three times with 600mL of n-hexane, washed with 5% sodium bicarbonate until neutral , concentrated under reduced pressure, and finally under a pressure of 5mmHg, distilled to obtain 144g of chloroester, with a content of 93% and a yield of 82.4%.

[0056] Add 144g chloroester (93%, 0.82mol) to 500mL acetone,...

Embodiment 3

[0060] The method for preparing chloroesters in Example 1 was repeated to obtain 14.3g chloroesters with a purity of 93% and a yield of 81.8%.

[0061] Add 18.0g of chloroester (93%, 0.1mol) into 50mL of acetonitrile, add 12.6g of potassium formate (0.15mol), and 1.61g of n-butylammonium bromide (0.005mol), heat up to reflux, react for 7 hours, cool to 0°C, filtered, distilled to recover the solvent, added 50 mL of ethyl acetate, washed once with water, and concentrated to obtain 18.1 g of diester with a content of 91% and a yield of 95.8%.

[0062] Add 19g of diester (91%, 0.11mol) into 50mL of methanol, add 0.42g of sodium acetate (0.005mol), react at room temperature for 3 hours, recover methanol by distillation under reduced pressure, add 50mL of ethyl acetate to dissolve, filter off sodium acetate After concentration, 17.2 g of alcohol ester was obtained, with a content of 90% and a yield of 97.7%.

[0063] Dissolve 16g of alcohol ester (91%, 0.11mol) in 50mL of acetonit...

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Abstract

The invention discloses a method for preparing 4-acetoxy-2-methyl-2-butenal. The method comprises the following steps of: carrying out a methyl esterification reaction, an ester exchange reaction and an oxidizing reaction on 1-acetoxy-4-chloro-3-methyl-2-butene to obtain a product of 4-acetoxy-2-methyl-2-butene-1-ol. According to the method, the problems of raw material cost and environment friendliness are comprehensively considered, the 4-acetoxy-2-methyl-2-butenal is synthesized through chloride ester through a three-step reaction which is mild in conditions and high in yield, an easily recovered organic solvent is adopted in the reaction of each step, the pollutant discharge is greatly reduced, the pollution problem is effectively solved due to the improvement of a synthetic route, the yield is improved, the raw material cost is reduced, the effective resource treatment is realized, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of organic chemistry and relates to a preparation method of 4-acetoxy-2-methyl-2-butenal. Background technique [0002] 4-Acetoxy-2-methyl-2-butenal, also known as five-carbon aldehyde (C5) or γ-acetoxytiglic aldehyde, is an important pharmaceutical intermediate. Five-carbon aldehyde has an isopentene structure, one end is an ester group, and the other end is an aldehyde group. The ester group can be converted into a variety of functional groups, and more importantly, it can be prepared into a phosphate compound, which can be combined with another five-carbon aldehyde through a wittig reaction. (such as pentacarbon phosphonate) aldehyde docking, synthesis of polyisoprene chains, is an important intermediate in the synthesis of vitamin A acetate and various carotenoids. [0003] There are many routes for synthesizing 4-acetoxy-2-methyl-2-butenal, among which the synthetic route mainly using isoprene as raw material ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/145C07C67/29
Inventor 陶正国关开创吴敏孙丹丹陈小兵
Owner GUANGZHOU LEADER BIO TECH
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