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Chemical synthesis method for 2-bromothiophene and derivative thereof

A technology of chemical synthesis and synthesis method, which is applied in the field of chemical synthesis of 2-bromothiophene and its derivatives, can solve the problems of low product purity, low yield, poor reaction selectivity, etc., and achieve the improvement of reaction selectivity and reaction yield. The effect of increasing the efficiency and improving the purity of the product

Inactive Publication Date: 2009-12-02
ZHEJIANG LIAOYUAN PHARM CO LTD
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Problems solved by technology

Therefore, it is more important to effectively synthesize 2-bromothiophene and its derivatives. Predecessors have also done a lot of research work on the selection of brominating agents and solvents: from the earlier use of Br2 / CH3COOH for bromination, but its Bromination selectivity and yield are poor, after that, transfer to other bromination combination research:
[0003] Document 1 [Convenient synthetic procedures for 2-bromothiophene Xiangtan Daxue Ziran Kexue Xuebao, 20 (3), 92-93 (English) 1998] uses perbrominated pyridinium hydrobromide as brominating agent, adopts thiophene in carbon tetrachloride Monobromination has achieved a certain effect, and the yield is about 90%, but the product purity is not high, generally 98%, and its promotion is greatly restricted due to the use of toxic carbon tetrachloride
[0004] Document 2 [Ishizaki, Masahiko; Takenaka, Junji (Tokuyama Kk, Japan). Jpn. Kokai Tokkyo Koho JP 07242657 A2 19 Sep 1995 Heisei, 5 pp. (Japan)] using bromine and ethylene glycol dimethyl ether in chloroform solvent The middle reaction generates 75% 2-bromothiophene, and its yield is on the low side, and the consumption of its bromine is relatively large simultaneously, and the HBr that generates is not recovered and utilized preferably and loses, and does not conform to atom economy
[0005] Document 3 [OH SE-HWA; JUNG JAE-YUN; PARK HEE-MOON; PARK SOO-YUL; KR960016128(B1), 1996-12-04] using hydrogen peroxide and hydrobromic acid solution or hydrogen peroxide, hydrobromic acid and bromine Mixed as a brominating agent, but the reaction is not thorough enough and the reaction selectivity is poor, resulting in low product purity, generally 95-98%

Method used

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  • Chemical synthesis method for 2-bromothiophene and derivative thereof
  • Chemical synthesis method for 2-bromothiophene and derivative thereof

Examples

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Effect test

Embodiment 1

[0026] Add 95g (1.131mol) of thiophene and 300ml of chloroform into a 1000ml three-necked reaction flask, start stirring, cool to -5°C, slowly add about 320g (1mol) of pyridinium tribromide in batches under stirring, after adding, continue to keep warm React for 0.5 hours, then add about 100ml of water, stir for 0.5 hours, let stand to separate the water layer, concentrate the organic layer to dryness, and rectify the concentrated solution under reduced pressure to obtain 148g (0.908mol) of 2-bromothiophene, the yield is 90.8%, the content 99.5%.

Embodiment 2

[0028] Add thiophene 95g (1.131mol), n-hexane 300ml, 2-picoline 101g (1.0mol) and 48% hydrobromic acid aqueous solution 337.5g (2mol) to a 1000ml three-necked reaction flask, start stirring, cool to -10°C, Slowly add 97.1 g (1.0 mol) of 35% hydrogen peroxide dropwise under stirring. After the addition is complete, continue the heat preservation reaction for 0.5 hours, let stand to separate the water layer, concentrate the organic layer to dryness, and rectify the concentrated solution under reduced pressure to obtain 2-bromothiophene 138.5g (0.85mol), the yield is 85%, and the content is 98.8%.

Embodiment 3

[0030] Add 100g (1.1905mol) of thiophene, 300ml of dichloromethane, 79g (1.0mol) of pyridine and 48.6g (0.5mol) of 35% hydrogen peroxide into a 1000ml three-necked reaction flask, start stirring, cool to -10°C, and slowly Add 80 g (0.5 mol) of bromine dropwise. After the addition is complete, continue the heat preservation reaction for 0.5 hours, let stand to separate the water layer, concentrate the organic layer to dryness, and rectify the concentrated solution under reduced pressure to obtain 145 g (0.8896 mol) of 2-bromothiophene. The rate is 88.96%, and the content is 99.2%.

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Abstract

The invention discloses a chemical synthesis method for 2-bromothiophene expressed as structural formula (II) and derivatives thereof, which comprises the following steps: mixing thiophene expressed as structural formula (I) or derivatives thereof and organic solvent, controlling the temperature to between 50 DEG C below zero and 20 DEG C, adding a brominating agent into the mixture, carrying out heat preservation reaction after the adding is finished, separating out an aqueous layer after full reaction, and concentrating and distilling an organic layer to obtain 2-bromothiophene or a derivative product thereof, wherein the brominating agent is selected from one of (1) pyridiniums tribromide, (2) mixture of pyridine compounds and bromine, (3) mixture of pyridine compounds, bromine and hydrogen peroxide, (4) mixture of pyridine compounds, bromine, hydrogen peroxide and hydrobromic acid, (5) mixture of pyridine compounds, hydrobromic acid and hydrogen peroxide, and (6) mixture of pyridine compounds, bromine and hydrobromic acid; and the organic solvent is dichloromethane or chloroform or dichloroethane. The chemical synthesis method has the advantages of cheap and easily obtained raw materials, little toxicity, high chemical reaction selectivity, high yield, good product quality, brominating agent recycle, and the like.

Description

1. Technical field [0001] The invention relates to a chemical synthesis method of 2-bromothiophene and its derivatives, in particular to a bromination method of thiophene and its derivatives. 2. Background technology [0002] 2-Bromothiophene and its derivatives are a key intermediate used in the organic synthesis process. This type of compound is used in the synthesis process of a large number of thiophene products, and its wide application can be seen. Therefore, it is more important to effectively synthesize 2-bromothiophene and its derivatives. Predecessors have also done a lot of research work on the selection of brominating agents and solvents: from the earlier use of Br2 / CH3COOH for bromination, but its Bromination selectivity and yield are poor, after that, transfer to other bromination combination research: [0003] Document 1 [Convenient synthetic procedures for 2-bromothiophene Xiangtan Daxue Ziran Kexue Xuebao, 20 (3), 92-93 (English) 1998] uses perbrominated py...

Claims

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Application Information

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IPC IPC(8): C07D333/28C07B39/00
Inventor 屠雄飞林咸权
Owner ZHEJIANG LIAOYUAN PHARM CO LTD
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