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The preparation method of 4-halo-2-methyl-2-butenoic acid ethyl ester

A technology of ethyl crotonate and ethyl pyruvate, which is applied in the field of chemical intermediate synthesis, can solve the problems of low total reaction yield and long process route, and achieve good reaction selectivity, simple overall process and low equipment requirements harsh effect

Active Publication Date: 2016-08-17
SHANGYU NHU BIOCHEM IND +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The method process route is longer, and the total yield of reaction is lower

Method used

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  • The preparation method of 4-halo-2-methyl-2-butenoic acid ethyl ester
  • The preparation method of 4-halo-2-methyl-2-butenoic acid ethyl ester
  • The preparation method of 4-halo-2-methyl-2-butenoic acid ethyl ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] A. Preparation of hydroxy compound (V)

[0033] Add 23.43g ethyl pyruvate (purity 99%) and 80ml toluene into a 250ml four-necked flask, stir and cool down to -10°C, start to add 91ml of vinylmagnesium chloride Grignard reagent (content 2.2mol / L, commercially available) The product, the solvent is tetrahydrofuran), the drip is completed in about 60 minutes, and the reaction is kept for 1 hour. After heat preservation, the product obtained is the condensate.

[0034] The condensate was slowly added dropwise to 150ml of dilute sulfuric acid (10% by mass), the reaction temperature was kept within 50°C during the dropping process, and the temperature keeping reaction was continued for 10 minutes after dropping. After standing for layering, the upper organic phase was separated, and the lower aqueous phase was extracted twice with toluene, with 30 ml of toluene each time. Combine and extract toluene to the organic phase, neutralize it with 100ml saturated sodium bicarbonate, sep...

Embodiment 2

[0038] A. Preparation of hydroxy compound (V)

[0039] Add 23.43g ethyl pyruvate (purity 99%) and 80ml toluene into a 250ml four-necked flask, stir and cool to -10℃, start to add 87ml vinylmagnesium bromide Grignard reagent (content 2.3mol / L, Commercially available product, the solvent is tetrahydrofuran), the drip is completed in about 60 minutes, and the reaction is kept for 1 hour. After heat preservation, the product obtained is the condensate. The condensate was slowly added dropwise to 150ml of dilute sulfuric acid (with a concentration of 10% by mass), the reaction temperature was kept within 50°C during the dropping process, and the temperature keeping reaction was continued for 10 minutes after dropping. After standing for layering, the upper organic phase was separated, and the lower aqueous phase was extracted twice with toluene, with 30 ml of toluene each time. Combine and extract toluene to the organic phase, neutralize it with 100ml saturated sodium bicarbonate, s...

Embodiment 3

[0043] A. The hydroxyl compound (V) was prepared in the same way as in Example 1

[0044] B. Preparation of bromocarbon five ester (I)

[0045] Add 22.85g of hydroxy compound (V) (purity 94.5%) and 60ml of dichloromethane into a 250ml four-necked flask, stir and cool the reaction mixture to 0°C, and start adding 32.0g of hydrobromic acid (mass percentage concentration 57%). , The drip is finished in about 30min, and the reaction is kept for 20min. Let stand to separate the layers, separate the organic phase, and extract the aqueous phase with 20 ml of dichloromethane and combine into the organic phase. The organic phase was neutralized with 80ml saturated sodium bicarbonate and then washed once with 80ml saturated sodium chloride. After washing, the dichloromethane was recovered to obtain 28.7g concentrate, which was compared and analyzed by GC with the commercially available standard bromocarbon pentacarboxylate (I) , The purity is 91.8%, and the yield is 84.8%.

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Abstract

The invention discloses a 4-halogenated-2-methyl-2-ethyl crotonate preparing method which includes following steps: (1) performing a Grignard reaction to ethyl pyruvate (II) and a vinyl magnesium halide Grignard reagent (III) to obtain a condensation compound (IV) after the reaction finished, and carrying out a hydrolysis reaction to the condensation compound (IV) to obtain a hydroxyl compound (V); and (2) performing a halogenating reaction to the hydroxyl compound and a haloid acid to obtain the 4-halogenated-2-methyl-2-ethyl crotonate (I). The 4-halogenated-2-methyl-2-ethyl crotonate preparing method is simple in total technology, allows raw materials to be obtained easily, is good in reaction selectivity, is less in by-products and is high in yield. The employed raw materials are all low-toxic or toxic-free and are all corrosiveness-free so that the method is not rigorous in requirement of devices, is environmental-friendly and is suitable for industrialized production.

Description

Technical field [0001] The invention relates to the synthetic field of chemical intermediates, in particular to a preparation method of ethyl 4-halo-2-methyl-2-butenoate. Background technique [0002] 4-halo-2-methyl-2-butenoic acid ethyl ester (hereinafter referred to as halogenated carbon five esters), which is the key intermediate for the synthesis of 8'-apo-β-carrotic acid ethyl ester. The synthesis methods mainly include vinyl propionitrile method, methyl vinyl ketone method and dimethoxyacetone method. [0003] Patent documents US4937308 and DE3244273 describe a method for preparing halogenated carbon pentaester by vinyl propionitrile method, and the reaction process is shown in the following formula: [0004] The method uses hydrogen chloride gas and bromine. The toxicity and corrosiveness of hydrogen chloride gas and bromine are increased, which requires high equipment, and the overall reaction yield is not ideal. [0005] Patent documents US4596889 and US5717128 describe th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/65C07C67/327
CPCC07C67/31C07C67/327C07C69/65C07C69/732
Inventor 张明锋黄国东吕国锋曾庆宇李小军
Owner SHANGYU NHU BIOCHEM IND
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