Synthesis method of 3-methylthiophene-2-aldehyde

A technology of methyl thiophene and synthesis method, which is applied in the direction of organic chemistry, can solve the problems of difficult separation of isomers, practical value of waste water, and difficult availability of raw materials, and achieve the effects of cost reduction, easy product purification, and high selectivity

Inactive Publication Date: 2013-03-27
QINGDAO FRONTIERCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to overcome the above-mentioned defects existing in the prior art field, the object of the present invention is to provide a synthetic method for 3-methylthiophene-2-carbaldeh

Method used

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  • Synthesis method of 3-methylthiophene-2-aldehyde
  • Synthesis method of 3-methylthiophene-2-aldehyde

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Experimental program
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Embodiment 1

[0019] The synthetic method of the 3-methylthiophene-2-carboxaldehyde of the present embodiment comprises the following steps successively:

[0020] The first step is to synthesize 3-methyl-2-bromothiophene: the three-necked flask is equipped with mechanical stirring, a thermometer, and a dropping funnel, and 98.17 g (1 mole) of 3-methylthiophene and 48% hydrogen bromide are added to the three-necked flask 202g (1.2 mole) of acid, cooled to 0°C, then control the temperature at 5-10°C and add 113.4g (1 mole) of hydrogen peroxide with a concentration of 30% dropwise, after the dropwise addition, raise the temperature to 20°C, stir for 2 hours and then let stand. Liquid separation, the organic layer was washed with sodium sulfite aqueous solution and sodium carbonate aqueous solution, and rectified under reduced pressure to obtain 165 g of 3-methyl-2-bromothiophene with a purity of 99.3% and a yield of 93.1%;

[0021] The second step is to synthesize 3-methylthiophene-2-carbaldeh...

Embodiment 2

[0023] The synthetic method of the 3-methylthiophene-2-carboxaldehyde of the present embodiment comprises the following steps successively:

[0024] The first step is to synthesize 3-methyl-2-bromothiophene: a three-necked flask is equipped with mechanical stirring, a thermometer, and a dropping funnel, and 98.17 g (1 mole) of 3-methylthiophene and 1.2 mole (with Bromide ion meter), cooled to 0°C, then controlled the temperature at 5-10°C, added dropwise 113.4g (1 mole) of hydrogen peroxide with a concentration of 30%, raised the temperature to 20°C after the dropwise addition, stirred for 2 hours, let stand, and separated the liquid , the organic layer was washed with aqueous sodium sulfite and aqueous sodium carbonate, and rectified under reduced pressure to obtain 162 g of 3-methyl-2-bromothiophene with a purity of 99.2% and a yield of 91.49%;

[0025] The second step is to synthesize 3-methylthiophene-2-carbaldehyde: add 25.5g (1.05mole) of magnesium chips, 20ml of tetrahy...

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Abstract

The invention discloses a synthesis method of 3-methylthiophene-2-aldehyde. The 3-methylthiophene-2-aldehyde is a compound intermediate with great value and can be widely used for synthesis in the fields of medicines, pesticides and the like. According to the synthesis method disclosed by the invention, 3-methylthiophene is taken as a raw material, bromination and Grignard reaction are performed, and then the reaction with N,N-dimethylformamide is performed, so that 3-methylthiophene-2-aldehyde is synthesized. The problems of poor selectivity, low yield, low purity, a large quantity of three wastes and the like in the existing synthesis method can be overcome, and the method disclosed by the invention is the method for synthesizing high-purity 3-methylthiophene-2-aldehyde under mild reaction conditions, which has the advantages of high selectivity and high yield.

Description

[0001] technical field [0002] The invention belongs to the technical field of synthetic methods of pharmaceutical intermediates, and in particular relates to a synthetic method of 3-methylthiophene-2-carbaldehyde. [0003] Background technique [0004] 3-Methylthiophene-2-carbaldehyde is a compound intermediate with high practical value and is widely used in medicine, pesticide and other fields. The existing documents US2008 / 21026 and WO2007 / 19884 propose to process 3-methylthiophene with butyllithium and then react with N,N-dimethylformamide to obtain 3-methylthiophene-2-carbaldehyde. This method will produce a kind of isomer 4-methylthiophene-2-carbaldehyde, which has about 20 percent, and its boiling point is similar to that of 3-methylthiophene-2-carbaldehyde, so the separation is difficult. And the diethyl ether and butyllithium used in the reaction are extremely flammable substances, and the use safety is low. There are also literatures (Tetrahedron Letters; vol.4...

Claims

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Application Information

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IPC IPC(8): C07D333/22
Inventor 王铁巍刘桂洪李小英刘国超
Owner QINGDAO FRONTIERCHEM
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