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Preparation method of 2,4-dibromo-butyricacid methyl ester

A technology of methyl dibromobutyrate and butyrolactone, which is applied in two fields, can solve the problems of low product purity, failure to obtain the target product, and difficulty in realizing large-scale industrial production, and achieve simple process and easy large-scale industrial production , low toxicity effect

Active Publication Date: 2010-11-10
山东格新精工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the reaction is to replace hydrogen by bromine at different positions, many side reactions will occur if the conditions are not well controlled, resulting in extremely low purity of the product, and even the target product cannot be obtained. Therefore, it is currently difficult to achieve large-scale industrial production

Method used

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  • Preparation method of 2,4-dibromo-butyricacid methyl ester
  • Preparation method of 2,4-dibromo-butyricacid methyl ester

Examples

Experimental program
Comparison scheme
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Embodiment 1）

[0013] The preparation method of the present embodiment has the following steps:

[0014] ①Add 100g of γ-butyrolactone into the three-necked flask and stir, then add 14g of red phosphorus and cool down to -10°C, start to slowly add 200g of bromine (that is, liquid bromine) dropwise, and then heat will be released. The temperature rises, and the dropping temperature is controlled to be less than or equal to 20° C., so that the reaction of 4-bromobutyryl bromide occurs. After the drop is completed, the stirring is continued at a temperature of 20° C. for 1 h, so that the reaction is completed.

[0015] ②Then slowly add 200g of bromine dropwise. At this time, heat will continue to be emitted, and the temperature will continue to rise. Control the dropping temperature to ≤80°C, thereby generating 2,4-dibromobutyryl bromide. Stirring was continued for 3 h at a temperature of 80° C. to complete the reaction.

[0016] ③Then cool down to -10°C, slowly add 12Og of methanol dropwise, a...

Embodiment 2～ Embodiment 5）

[0019] Each embodiment is basically the same as Embodiment 1, and the differences are shown in Table 1.

[0020] Table 1

[0021]

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Abstract

The invention discloses a preparation method of 2,4-dibromo-butyricacid methyl ester. The method comprises the following steps of: (1) adding a phosphorus-containing substance to gamma-butyrolactone in the presence of stirring, and then cooling to -15 to -5 DEG C; slowly dropping a bromating agent by controlling the dropping temperature to be 0-20 DEG C and stirring for 1-2 hours after dropping; (2) slowly dropping a bromating agent being the same as that in the step (1) by controlling the dropping temperature to be 60-120 DEG C, and stirring for 2-4 hours after dropping; (3) cooling to -15 to -5 DEG C, slowly dropping methanol by controlling the dropping temperature to be 0-5 DEG C and stirring for 1-2 hours after dropping; and (4) treating to obtain a finished 2,4-dibromo-butyricacid methyl ester product. The method has short synthetic route, and an intermediate product is not needed to be separated and purified; through controlling the bromination temperature, the position and the degree of the bromination are controlled; and the yield reaches higher than 92 percent, and the purity reaches higher than 98 percent.

Description

technical field [0001] The invention relates to a preparation method of an organic compound, in particular to a preparation method of 2,4-dibromobutyric acid methyl ester. Background technique [0002] Methyl 2,4-dibromobutyrate is an important pharmaceutical intermediate. At present, the preparation of 2,4-dibromobutyric acid methyl ester is based on γ-butyrolactone as the starting material, and the 4-bromobutyric acid is obtained by HBr ring opening, and the product is separated and purified, and then carried out with the brominating agent. The reaction is to obtain 2,4-dibromobutyric acid, and finally esterified with methanol to obtain 2,4-dibromobutyric acid methyl ester. Since the reaction is to replace hydrogen with bromine at different positions, many side reactions will occur if the conditions are not well controlled, resulting in extremely low product purity and even failure to obtain the target product. Therefore, it is currently difficult to achieve large-scale i...

Claims

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Application Information

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IPC IPC(8): C07C69/63C07C67/14
Inventor 杨润苗陈金良刘玉海周健
Owner 山东格新精工有限公司