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A kind of preparation method of 2-methyl-4-acetoxy-2-butenal

A technology of acetoxyl and crotonaldehyde, applied in the field of medicinal chemistry, can solve the problems of uncomfortable and simple operation, low substrate activity and high equipment requirements, and achieves the effects of suitable reactivity, easy reaction and good stability.

Active Publication Date: 2022-04-01
XINFA PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0035] 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 High pressure (130-150 standard atmospheric pressure), high equipment requirements, not suitable for easy industrial operation

Method used

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  • A kind of preparation method of 2-methyl-4-acetoxy-2-butenal
  • A kind of preparation method of 2-methyl-4-acetoxy-2-butenal
  • A kind of preparation method of 2-methyl-4-acetoxy-2-butenal

Examples

Experimental program
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Effect test

Embodiment 1

[0087] Example 1: Preparation of 2-methyl-2-ethyl-5-formyl-4,7-dihydro-1,3-dioxin (Ⅲ1)

[0088] Into a 500 ml stainless steel autoclave connected with stirring and a thermometer, add 142.0 g (1.0 mol) of 2-methyl-2-ethyl-4,7-dihydro-1,3-dioxin (II1), 150.0 gram of toluene, 0.8 gram of three (triphenylphosphine) carbonyl rhodium hydride, 0.5 gram of triphenylphosphine, airtight autoclave, gas in nitrogen replacement kettle 3 times, then pass into synthetic gas CO / H 2 (volume ratio 1:1), keep the synthesis gas pressure at 4.0-5.0MPa, start stirring, raise the temperature to 95-100°C, react for 4 hours, cool down, replace with nitrogen 3 times, remove the reaction liquid, and wash with 30 grams of toluene Reactor, remove the catalyst by filtration, and distill the filtrate to recover toluene, then distill under reduced pressure (110-120°C / 1-2mmHg) to obtain 160.5 grams of 2-methyl-2-ethyl-5-formyl-4,7-dihydro -1,3-dioxin (Ⅲ1), the yield is 93.3%, and the gas phase purity is 99.6...

Embodiment 2

[0089] Example 2: Preparation of 2-methyl-2-tert-butyl-5-formyl-4,7-dihydro-1,3-dioxin (Ⅲ2)

[0090]Add 170.0 g (1.0 mol) of 2-methyl-2-tert-butyl-4,7-dihydro-1,3-dioxin (Ⅱ2) into a 500 ml stainless steel autoclave connected with a stirring and thermometer , 120 gram toluene, 0.9 gram three (triphenylphosphine) rhodium chlorides, 0.6 gram triphenylphosphine, airtight autoclave, the gas in the nitrogen replacement kettle is 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 5 hours, cool down, replace with nitrogen 3 times, remove the reaction liquid, and wash with 30 grams of toluene Reactor, remove the catalyst by filtration, and distill the filtrate to recover toluene, then distill under reduced pressure (110-125°C / 1-2mmHg) to obtain 183.2 grams of 2-methyl-2-tert-butyl-5-formyl-4,7-di Hydrogen-1,3-dioxin (Ⅲ2), the yield is 91.6%, and the gas phase puri...

Embodiment 3

[0091] Example 3: Preparation of 2-formyl-4-acetoxy-1-butene (IV)

[0092] In the 500 milliliter four-necked flask that is connected with stirring, thermometer, reflux condenser, add 200 gram toluene, 86.0 gram (0.5 moles) the 2-methyl-2-ethyl-5-formyl-4 that embodiment 1 prepares , 7-dihydro-1,3-dioxin (Ⅲ1), 48.0 grams (0.8 moles) of acetic acid, 1.0 grams of water, 0.3 grams of p-toluenesulfonic acid, stirred at 110-112 ° C for 5 hours, while collecting By-product 2-butanone. Cool to 20 to 25°C, change to a distillation system, first distill to recover toluene and excess acetic acid, and then change to high vacuum vacuum distillation (85-100°C / 1-2mmHg) to obtain 67.6 grams of 2-formyl-4-acetoxy -1-butene (Ⅳ), the yield is 95.2%, and the gas phase purity is 99.5%.

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Abstract

The invention provides a preparation method of 2-methyl-4-acetoxy-2-butenal (I), which utilizes 2,2-disubstituent-4,7-dihydro-1,3-diox Heptin (II) and synthesis gas are used as raw materials to prepare 2,2-disubstituent-5-formyl-4,7-dihydro-1,3-dioxin (III) through hydroformylation reaction, Then react with acetylating reagent to prepare 2-formyl-4-acetoxy-1-butene (IV), and then obtain 2-methyl-4-acetoxy-2-butenal through double bond isomerization (Ⅰ). The method of the invention has cheap and easy-to-obtain raw materials and low cost; the process flow is short, the reaction is easy to realize, the operation is safe and convenient, the waste water generation is small, and it is environmentally friendly; the reaction intermediate product is stable, the reaction activity is suitable, the reaction selectivity is high, the side reaction is few, and the yield is low. High efficiency, suitable for industrial production.

Description

technical field [0001] The invention relates to a 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-acetoxy group-2-butenal is summarized as following preparation method according to the difference of main raw material used and involved unit reaction: [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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/145C07C67/24C07C67/293C07D321/06
CPCC07C67/24C07C67/293C07D321/06C07C69/145
Inventor 吕强三戚聿新周立山江枭南张明峰
Owner XINFA PHARMA