A kind of method for preparing 2-chloro-4-nitroimidazole

A technology of nitroimidazole and clomidazole, which is applied in the direction of organic chemistry, can solve the problems of easy explosion accidents, many by-products, and difficult industrialization, and achieve the effects of easy industrial production, high product quality, and mild reaction conditions

Inactive Publication Date: 2016-03-23
YANCHENG INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The general synthesis method is to use imidazole as a raw material, prepare 1,4-dinitroimidazole through nitration, then rearrange and transposition to prepare 2,4-dinitroimidazole, and halogenate to obtain the final product 2-chloro-4-nitroimidazole. The general yield of this method is relatively low, and there are many by-products, especially in the step of rearrangement and transposition. Because 1,4-dinitroimidazole and 2,4-dinitroimidazole are high-energy compounds[2], they can be regenerated at high temperature. During the exhaust reaction process, explosion accidents are extremely prone to occur, so this process route is difficult to industrialize

Method used

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  • A kind of method for preparing 2-chloro-4-nitroimidazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 9.94g of aminoacetaldehyde diethyl acetal (0.074mol), 20.6g of S-methylisothiourea sulfate (0.074mol) and 16.5ml of water into the three-necked flask successively, then raise the temperature to 110°C, and stir the reaction for 1.5h. Stop responding. Evaporate the solvent, then add 13.0g of 37% hydrochloric acid (mass percent concentration, the same as in the following examples) to the reaction solution, stir at 65°C for 1 hour, add 50ml of water, evaporate the solvent, add 30ml of acetone, and precipitate light yellow crystals. After filtration, the crude product was recrystallized with 30ml of ethanol-water to obtain 15.90g of off-white powdery solid 2-aminoimidazole sulfate, yield 81.5%, mp271.2~273.0℃.

[0022] Add 15g of 37% hydrochloric acid and 10.56g of 2-aminoimidazole sulfate (0.04mol) into a three-necked flask, and dropwise add 10.8g of 25.9% sodium nitrite solution (mass percentage concentration, the same as the following examples) (0.04mol) under ice-wat...

Embodiment 2

[0025] Add 7.8g of aminoacetaldehyde dimethyl acetal (0.074mmol), 20.6g of S-methylisothiouronium sulfate (0.074mmol) and 16.5ml of water into the three-necked flask successively, then raise the temperature to 110°C, and stir for 1.5h. Stop responding. Evaporate the solvent, then add 13.0g of 37% hydrochloric acid (mass percent concentration, the same as in the following examples) to the reaction solution, stir at 65°C for 1 hour, add 50ml of water, evaporate the solvent, add 30ml of acetone, and precipitate light yellow crystals. After filtration, the crude product was recrystallized with 30ml of ethanol-water to obtain 15.31g of off-white powdery solid 2-aminoimidazole sulfate, yield 78.5%, mp271.2~273.0℃.

[0026] Add 15g37% hydrochloric acid and 3.3g2-aminoimidazole (0.04mol) into the three-necked flask, add dropwise 10.8g25.9% sodium nitrite solution (mass percentage concentration, the same as the following examples) (0.04mol) under ice-water bath, maintain The reaction ...

Embodiment 3

[0029] With the method of embodiment 1, the difference is that the reaction molar ratio of aminoacetaldehyde diethyl acetal and S-methylisothiouronium sulfate is 1:5.

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Abstract

The invention discloses a method for preparing 2-chloro-4-nitroimidazole. The method comprises the following steps of reacting aminoacetaldehyde acetal with S-methyl-iso-thiourea sulphate to synthesise 2-aminoimidazole sulphate, and then performing diazotization reaction on 2-aminoimidazole sulphate and sodium nitrite; then performing chlorination reaction on a reactant obtained from the former step and cuprous chloride to obtain 2-chloro-imidazole; and finally performing nitration reaction with nitric acid to obtain 2-chloro-4-nitroimidazole. The synthesis method disclosed by the invention is capable of avoiding rearrangement and transposition, is moderate in reaction conditions, less in pollution, and easily realizes industrialized production.

Description

technical field [0001] The invention belongs to the technical field of chemical intermediate synthesis and relates to a preparation method of 2-chloro-4-nitroimidazole. Background technique [0002] Imidazole compounds are widely used in the fields of medicine, pesticides, electroplating and cosmetics. 2-Chloro-4-nitroimidazole is one of the important intermediates of imidazoles [1], which can be used to prepare tuberculosis drugs in medicine. Such drugs It has good antibacterial effect. Under the situation of high incidence of pulmonary tuberculosis in various countries in the world, the research and development of such intermediates has important social and economic value. The general synthesis method is to use imidazole as a raw material, prepare 1,4-dinitroimidazole through nitration, then rearrange and transposition to prepare 2,4-dinitroimidazole, and halogenate to obtain the final product 2-chloro-4-nitroimidazole. The general yield of this method is relatively low, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D233/92
Inventor 赵玲玲戴勇祁刚
Owner YANCHENG INST OF TECH
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