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Method for preparing antiform - 4 - acetoxy - 2 - methyl - butenoic aldehyde

A technology of acetoxy and crotonaldehyde, which is applied in the preparation of pentacyclic unsaturated carbon frame compounds and the field of preparation of trans-4-acetoxy-2-methyl-2-butenal, which can solve the problem of receiving The efficiency cannot reach the yield, the process cost is increased, and the production cost is increased, so as to achieve the effects of reducing reaction steps, easy recycling, and less environmental pollution

Inactive Publication Date: 2007-12-26
GUANGZHOU WISDOM BIO TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But still be to use DMSO when this method oxidizes chloroform ester, the shortcoming of the method provided by U.S. Patent 4175204 exists equally; This method has also used expensive chemical reagents such as TEMPO, the ion-exchange resin that loaded periodic acid, makes the method's The process cost is greatly increased; from isoprene to the synthesis of chloroester requires a two-step reaction, in the first step reaction needs to add excess isoprene to suppress the production of addition by-products, the one-time utilization of isoprene The yield is only 33%, and the total yield is only 30% based on the yield calculated by the one-time use of isoprene
The inventor has repeatedly verified the technical route disclosed in this article, and the yield can not reach the yield described in the article.
We react according to the method described in this article, with 4 times the isoprene of the amount of substance of sodium hypochlorite, according to isoprene calculation yield only has 10% to 15% chlorohydrin; Chloroester yield also only has About 80%, and wherein cis-chloroester accounts for 15% to 20%; The last step according to the condition of this paper, the final product yield is only 50%, and the by-product of the reduction product methyl sulfide of DMSO and chloroester is close to 40%, in order to reduce by-products, it is necessary to feed nitrogen into the reactor to drive away methyl sulfide, so that the yield of the final product can reach 80%, but this operation is very cumbersome and increases production costs

Method used

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  • Method for preparing antiform - 4 - acetoxy - 2 - methyl - butenoic aldehyde

Examples

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Effect test

example 1

[0015] (1) Add 1 mol of isoprene to 2 mol of acetic anhydride solution, stir, cool to -10°C to 0°C, maintain this temperature, then add 1 mol of tert-butyl hypochlorite dropwise within 1.5 hours. After the dropwise addition, the temperature was raised to 80°C, and 0.05mol p-toluenesulfonic acid was added to react for 10 hours. After the reaction, 500ml ice water was added, and the organic phase was separated, dried with 20g anhydrous sodium sulfate, and filtered to remove the desiccant. At 5 mmHg, 0.8 mol of chloroester was distilled, with a content of 93%.

[0016] (2) Add 1mol of chloroester to 500ml of toluene, add 1mol of hexamethylenetetramine, keep the temperature at about 40°C, react for 8 hours, then add 500ml of water, heat up to 80°C, and then add 2mol of glacial acetic acid Add it dropwise within 2 hours, continue to react for 10 hours, divide the organic phase after the completion of the reaction, dry with 20g of anhydrous sodium sulfate, and under 0.5mmHg, distill...

example 2

[0018] (1) Add 1 mol of isoprene to a solution of 2 mol of acetic anhydride, stir, cool to -10-0°C, maintain this temperature, then add 1 mol of tert-butyl hypochlorite dropwise within 1.5 hours. After the dropwise addition, the temperature was raised to 80°C, and 0.1mol sulfuric acid was added to react for 10 hours. After the reaction, 500ml of ice water was added, the organic phase was separated, dried with 20g of anhydrous calcium chloride, and the desiccant was filtered off. At 5 mmHg, 0.81 mol of chloroester was distilled, with a content of 93%.

[0019] (2) Add 1 mol of chloroester to 500 ml of acetonitrile, add 1 mol of hexamethylenetetramine, keep the temperature at about 40°C, react for 8 hours, then filter, add 500 ml of water to the filter cake to dissolve, then add 500 ml of 1,2- Ethylene dichloride was heated up to 80°C, and then 2mol glacial acetic acid was added dropwise within 2 hours, and the reaction was continued for 6 hours. After the reaction was completed...

example 3

[0021] (1) Add 1 mol of isoprene to 2 mol of acetic anhydride solution, stir, cool to -10-0°C, maintain this temperature, then add 1 mol of tert-butyl hypochlorite dropwise within 1.5 hours. After the dropwise addition, raise the temperature to 80°C, add 0.1mol nitric acid to react for 10 hours, add 500ml ice water after the reaction, separate the organic phase, dry it with 20g anhydrous sodium sulfate, and filter off the desiccant. At 5 mmHg, 0.78 mol of chloroester was distilled, with a content of 91%.

[0022] (2) Add 1 mol of chloroester to 500 ml of petroleum ether, add 1 mol of hexamethylenetetramine, keep the temperature at about 40°C, react for 8 hours, then add 500ml of water, heat up to 90°C, and then add 2 mol of ice Acetic acid was added dropwise within 2 hours, and the reaction was continued for 6 hours. After the reaction, the organic phase was separated, dried with 20 g of anhydrous sodium sulfate, and distilled at 0.5 mmHg to obtain 0.74 mol of pentacarbonaldeh...

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Abstract

This invention provides a method for preparing trans-4-acetoxy-2-methyl-2-crotonaldehyde. The method comprises: reacting isoprene and tert-butyl hypochlorite in acetic anhydride solution to obtain chlorine-containing ester, reacting with urotropine, and hydrolyzing to obtain trans-4-acetoxy-2-methyl-2-crotonaldehyde. The method has such advantages as few reaction procedures, easy operation, high isoprene conversion rate, high yield (40-56%), no need for DMSO during the oxidation process, no byproduct, low raw material cost, easy recovery of solvent, little environmental pollution and low cost, and is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of organic chemistry, in particular to a preparation method of a pentacyclic unsaturated carbon frame compound, in particular to a preparation method of trans-4-acetoxy-2-methyl-2-butenal. Background technique [0002] Trans-4-acetoxy-2-methyl-2-butenal is a key intermediate for the artificial synthesis of vitamin A and its derivatives, and its chemical structure is . At present, the synthesis of trans-4-acetoxy-2-methyl-2-butenal by domestic manufacturers adopts the process of using acetone dimethyl acetal as the starting material. The process route is long, the yield is low, the raw materials are expensive, and the cost is relatively high. . [0003] U.S. Patent "METHOD OF PREPARING E-4-ACETOXY-2-BUTENAL" (Patent No. 4175204) discloses a method for preparing trans-4-acetoxy-2-methyl-2-butenal, specifically using Isoprene reacts with sodium hypochlorite to generate chlorohydrins, then reacts chlorohydrins with ac...

Claims

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Application Information

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IPC IPC(8): C07C69/145C07C67/14C07C67/313
Inventor 吴世林邸维龙
Owner GUANGZHOU WISDOM BIO TECH
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