Preparation method of 2-methyl-4-acetoxy-2-butenal with high yield

A technology of acetoxy and crotonaldehyde, applied in the field of medicinal chemistry, can solve the problems of unsuitable and simple operation, low substrate activity, high equipment requirements, etc., and achieve the effect of suitable reaction activity, stable product and high reaction selectivity

Active Publication Date: 2020-01-31
XINFA PHARMA
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  • Abstract
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Problems solved by technology

[0029] Although the 7-atom economy of this synthetic route is high, the 1,4-diacetoxy-2-butene used in the hydroformylation reaction contains two ester functional groups, the substrate activity is low, and special ligands are required. The reaction process The pressure is high (the pressure is 130-150 standard atmospheric pressure), the equipment requirements are high, and it is not suitable for industrialized simple operation

Method used

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  • Preparation method of 2-methyl-4-acetoxy-2-butenal with high yield
  • Preparation method of 2-methyl-4-acetoxy-2-butenal with high yield
  • Preparation method of 2-methyl-4-acetoxy-2-butenal with high yield

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] Embodiment 1: Preparation of 3-formyl tetrahydrofuran (Ⅲ)

[0077] Into the 500 ml stainless steel autoclave connected with stirring and thermometer, add 70.0 g (1.0 mole) 2,5-dihydrofuran (II), 140 g toluene, 0.5 g tris(triphenylphosphine) carbonyl rhodium hydride, 0.5 gram of triphenylphosphine, sealed autoclave, nitrogen replacement autoclave gas 3 times, then pass into synthesis gas CO / H 2 (Volume ratio 1:1), keep the synthesis gas pressure at 4.0-5.0MPa, start stirring, raise the temperature to 90-95°C, react for 4 hours, cool down, replace with nitrogen 3 times, remove the reaction liquid, and wash the reaction with 30 grams of toluene Still, the catalyst was removed by filtration, and after the filtrate was distilled to recover toluene, it was distilled under reduced pressure (80-90° C. / 1-2 mmHg) to obtain 94.6 grams of 3-formyl tetrahydrofuran (Ⅲ), with a yield of 94.6% and a gas phase purity of 99.7%.

Embodiment 2

[0078] Embodiment 2: Preparation of 3-formyl tetrahydrofuran (Ⅲ)

[0079] In the 500 milliliter stainless steel autoclave that is connected with stirring, thermometer, add 70.0 gram (1.0 mole) 2,5-dihydrofuran (II), 180 gram toluene, 0.5 gram tris(triphenylphosphine) rhodium chloride, 0.6 gram of triphenylphosphine, sealed autoclave, nitrogen replacement autoclave gas 3 times, then pass into synthesis gas CO / H 2 (volume ratio 1:1), keep the synthesis gas pressure at 5.0-6.0MPa, start stirring, raise the temperature to 100-105°C, react for 4 hours, cool down, replace with nitrogen 3 times, remove the reaction liquid, and wash the reaction with 30 grams of toluene Still, the catalyst was removed by filtration, and after the filtrate was distilled to recover toluene, it was distilled under reduced pressure (80-90° C. / 1-2 mmHg) to obtain 93.8 grams of 3-formyl tetrahydrofuran (Ⅲ), with a yield of 93.8% and a gas phase purity of 99.6%.

Embodiment 3

[0080] Example 3: Preparation of 2-formyl-4-acetoxy-1-butene (IV)

[0081] In the 500 milliliter four-necked flask that is connected with stirring, thermometer, reflux condenser, add 200 grams of toluene, 50.0 grams (0.5 moles) of 3-formyl tetrahydrofuran (Ⅲ) prepared in Example 1, 48.0 grams (0.8 moles) of acetic acid , 0.20 g of p-toluenesulfonic acid, stirred and reacted at 110-112°C for 5 hours. Cool to 20 to 25°C, change to a distillation system, first distill to recover toluene and excess acetic acid, then change to high vacuum vacuum distillation (85-100°C / 1-2mmHg) to obtain 68.5 grams of 2-formyl-4-acetoxy 1-butene (Ⅳ), the yield is 96.5%, and the gas phase purity is 99.3%.

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Abstract

The invention provides a preparation method of 2-methyl-4-acetoxy-2-butenal (I) with high yield. The preparation method comprises the steps: with 2,5-dihydrofuran (II) and synthesis gas as raw materials, carrying out hydroformylation reaction under the action of a catalyst to prepare 3-formyl tetrahydrofuran (III); then carrying out a reaction with an acetylation reagent under the action of a catalyst to prepare 2-formyl-4-acetoxy-1-butene (IV); and carrying out double bond isomerization under the action of a catalyst to obtain 2-methyl-4-acetoxy-2-butenal (I). The method has the advantages ofcheap and accessible raw materials and low cost; the process flow is short, the reaction is easy to realize, the operation is safe, simple and convenient, the wastewater yield is low, and the green and environment-friendly effects are achieved; the method has the advantages of stable reaction intermediate product, proper reaction activity, high reaction selectivity, fewer side reactions and highyield, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a high-yield preparation method of 2-methyl-4-acetoxy-2-butenal, which belongs to the technical field of medicinal chemistry. Background technique [0002] 2-methyl-4-acetoxy-2-butenal (I) is a key intermediate for the preparation of vitamin A acetate and various carotenoids, and its structural formula is as follows: [0003] [0004] The synthetic method of 2-methyl-4-acetoxyl group-2-butenal is summarized as following according to the difference of main raw material used and involved unit reactions: [0005] 1. 1,1-dimethoxyacetone method [0006] U.S. Patent Documents US4256878 and US5453547 use 1,1-dimethoxyacetone as a raw material to obtain 3-methyl-3-hydroxyl-4,4-dimethoxy-1-butyne through ethynylation, and hydrogen is selected 3-methyl-3-hydroxyl-4,4-dimethoxy-1-butene is obtained by hydrogenation, and then esterified with acetic anhydride to obtain 3-methyl-3-acetoxy-4,4 -dimethoxy-1-butene, and then obtain 2-met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/24C07C69/145
CPCC07C67/24C07C67/293C07D307/12C07C69/145
Inventor 周立山戚聿新吕强三于大伟鞠立柱
Owner XINFA PHARMA
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