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Process for synthesizing 1-chlorine-2-methyl-4-acetoxy-2-butylene

A technology of an acetoxy group and a synthetic method, applied in the field of chemistry, can solve problems such as poor product yield and content, poor product content, and increased impurities, and achieve the effects of mild reaction system, low cost, and high content and yield.

Active Publication Date: 2011-06-01
ZHEJIANG MEDICINE CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, after experimental verification, it was found that the yield and content of the product were very poor during the chlorohydrination reaction
[0011] Usually the chloroalcoholation reaction of olefin can lead chlorine in the calcium hydroxide aqueous suspension, utilizes the active hypochlorous acid of generation to directly carry out chlorohydrinization ((Encyclopedia of Chemical Engineering) Editorial Board, Encyclopedia of Chemical Industry, Chemical Industry Press, 1996 the first 1st edition, Vol.16, P719-729); but we found that the content of the obtained product was very poor after experimental verification, which may be due to the presence of free chlorine and other miscellaneous ions that caused the double bond of olefins to undergo side reactions such as dichloro addition , resulting in an increase in impurities

Method used

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  • Process for synthesizing 1-chlorine-2-methyl-4-acetoxy-2-butylene

Examples

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Effect test

Embodiment 1

[0029] Example 1: Preparation of 1-chloro-2-hydroxyl-2-methyl-3-butene and 1-chloro-2-methyl-4-hydroxyl-2-butene mixture

[0030]Put a 500ml three-neck bottle equipped with a thermometer and a solid feeding port into an alcohol cooling bath; add 68g (1mol) of isoprene, 100ml of water and 0.5g of inhibitor hydroquinone; Add tetrachloroglycocuril (95% available chlorine) in batches from the feeding port, 56 g (0.2 mol) in total, and add in about 1 hour, then continue to insulate and stir for 1 hour, filter, wash the filter cake with 15 ml of water, and it is a loose white powder solid. The filtrates were combined and allowed to stand for separation. The organic layer was lower than 40°C to recover unreacted isoprene under reduced pressure to obtain 90 g of crude product. Gas phase analysis showed that the total content of the product was 92.5%, and the yield was 92.1%. It can be directly used in the next reaction; the water layer is 99.5 grams, and it will be used in the next re...

Embodiment 2

[0031] Embodiment 2: material proportioning, operating temperature and aftertreatment are with embodiment 1, and difference is that reaction water is the waste water layer in embodiment 1, gets crude product 93g, gas phase analysis shows that product total content is 89.5%, yield 92.1%. The filter cake is a loose white powder solid, and the water layer is 98 grams.

Embodiment 3

[0032] Embodiment 3: material proportioning, operating temperature and aftertreatment are the same as embodiment 1, the difference is that the water for reaction is the waste water layer in embodiment 2, obtains crude product 94.5g, gas phase analysis shows that product total content is 90.5%, yield 94.6% .

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Abstract

The present invention discloses a synthetic method of 1-chlorine-2-methyl-4-acetoxy-2-butene, an important intermediate for synthesizing VA acetate. The existing method adopts chlorohydrin reaction to prepare the product and has the problems of poor yield rate and content. In the method, isoprene is used as the raw material for the chlorohydrin reaction so as to prepare the mixture of addition products of 1-chlorine-2-hydroxy-2-methyl-3-butene and 1-chlorine-2-methyl-4-hydroxy-2-butene. Under the influence of acid catalysis, the mixture reacts with acetic anhydride to prepare the 1-chlorine-2-methyl-4-acetoxy-2-butene. The method is characterized in that the chlorohydrin reaction is done in the reaction system that consists of tetrachloroglycine urea and water. The raw materials used in the method has high content of available chlorine and less heteroion; the reaction system is mild; the content and the yield of the product are high; the three-waste is greatly reduced; the cost is low; and the method has high industrial value.

Description

technical field [0001] The invention relates to the field of chemistry, in particular to a method for synthesizing an important intermediate 1-chloro-2-methyl-4-acetoxy-2-butene for the synthesis of VA acetate. Background technique [0002] Vitamin A (VA) and its derivatives are a class of important medicines, and the products of major companies in the world are mainly based on VA acetate (Encyclopedia of Chemical Industry, Chemical Industry Press, first edition in 1996, Vol.16 , P719-729). 4-Acetoxy-2-methyl-2-buten-1-aldehyde (MW142, referred to as five-carbon aldehyde) is a C characterized by Wittig reaction 15 +C 5 Route Synthesis V A The key intermediate of acetate (Tanaka, USP5,424,478, Process for producing Vitamin A Derivatives, [P] 1995; Tanaka, et al., JP06,329,623, Preparation of Vitamin A Derivatives, [P] 1994; Zutter, Ulrich , Ep648,735, Preparation of an intermediate for Vitamin A acetate, [P] 1995; Wang Lanming, Beijing Medicine, New Synthetic Technology o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/145C07C67/08C07C29/64
Inventor 马文鑫沈润溥胡四平陈春峰代世荣
Owner ZHEJIANG MEDICINE CO LTD
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