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Method for preparing 2-nitroimidazole

A technology of nitroimidazole and aminoimidazole, which is applied in the field of synthesis of 2-nitroimidazole, can solve the problems of large amount of catalyst 4-lutidine, low extraction efficiency, long reaction time, etc., and shorten the extraction time, The effect of saving extraction solvent and controlling cost

Inactive Publication Date: 2012-04-18
WUHAN SYNCHALLENGE UNIPHARM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above method has the following disadvantages: method one, the used reaction time is long, and the yield is too low; method two, the reaction solution is more during extraction, resulting in low extraction efficiency, and too many extracts used; method three, the reaction solution is relatively low during extraction. More lead to longer extraction time, larger amount of catalyst 4-lutidine, higher cost, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1. Add 15g of 2-aminoimidazole sulfate, 100mL of water and 100mL of 40wt% fluoboric acid in a flask, and add dropwise 100mL of aqueous solution containing 40g of sodium nitrite after cooling to about -3°C, and drop it in about 45 minutes. Stir at 0°C for 1 hour after completion, then pour into 1.5L water containing 200g of copper sulfate pentahydrate and 2g of bipyridine, add 40g of sodium nitrite while stirring, stir at room temperature for 3 hours after addition, then add concentrated hydrochloric acid Adjust the pH to 2, extract with ethyl acetate for 12 hours in a liquid-liquid extraction device, and then concentrate the extract to 1 / 4 of the total volume. After standing and cooling, 10.3 g of light yellow crystals are precipitated. The yield is 80%, and the mother liquor is reserved for the next step. For one extraction.

Embodiment 2

[0025] Example 2. Add 15g of 2-aminoimidazole sulfate, 100mL of water and 100mL of 40% fluoroboric acid in the flask, and add dropwise 100mL of aqueous solution containing 40g of sodium nitrite after cooling to about -3°C. After about 45 minutes, add Stir at 0°C for 1 hour after completion, then pour into 1.5L water containing 200g of copper sulfate pentahydrate and 2g of bipyridine, add 40g of sodium nitrite while stirring, stir at room temperature for 3 hours after addition, then add concentrated hydrochloric acid Adjust the pH to 2, extract with ethyl acetate for 12 hours in a liquid-liquid extraction device, use the mother liquor recovered in the previous example for part of the extract, concentrate the extract to 1 / 4 of the total volume after extraction, and let it stand for cooling 11.0 g of pale yellow crystals were precipitated, with a yield of 86%.

Embodiment 3

[0030] Example 3. Add 15g of 2-aminoimidazole sulfate, 100mL of water and 100mL of 40% fluoboric acid in the flask, and add dropwise 100mL of aqueous solution containing 40g of sodium nitrite after cooling to about -3°C, and drop it in about 45 minutes. Stir at 5°C for 1 hour after completion, then pour into 1.5L water containing 200g of copper sulfate pentahydrate and 2g of bipyridine, add 40g of sodium nitrite while stirring, stir at room temperature for 3 hours after addition, and then add concentrated hydrochloric acid Adjust the pH to 2, evaporate half of the water under reduced pressure, and then extract with ethyl acetate for 12 hours in a liquid-liquid extraction device. Part of the extract is recovered in the previous example. After extraction, the extract is concentrated to the total volume 1 / 4 of the product, 10.9 g of pale yellow crystals were precipitated upon standing cooling, with a yield of 85%.

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Abstract

The invention discloses a method for preparing 2-nitroimidazole, which comprises the following steps of: adding 40% of fluoboric acid and water in 2-amino-imidazole sulfate; dropwise adding a sodium nitrite aqueous solution at -30-3 DEG C while stirring to obtain a diazonium salt; pouring the diazonium salt into a copper salt aqueous solution or a mixed catalyst aqueous solution of the copper salt which is -5-10 DEG C while stirring; adding sodium nitrite and stirring for 2-9 hours at room temperature and then adjusting the pH value to be 2; extracting continuously by using an extractor, concentrating an extract and standing to separate out a rough product; and recentralizing the rough product, wherein mother liquid can be added in an extraction kettle for recycling. The invention has theadvantages of reducing the volume of reaction liquid, lowering the consumption of the extract during recycling the extract, improving the yield and facilitating the industrialized production.

Description

technical field [0001] The invention belongs to the technical field of organic chemistry, and in particular relates to a synthesis method of 2-nitroimidazole. Background technique [0002] 2-Nitroimidazole is an intermediate of Misonidazole, a tumor radiosensitizer. The synthetic method of 2-nitroimidazole mainly contains following several kinds at present: [0003] 1.J.Am.Chem.Soc., 1965,87(2), 387-9. It uses copper sulfate as a catalyst, puts it aside for 16 hours, and then acidifies it with nitric acid. %. [0004] 2. Chinese Journal of Pharmaceutical Industry, 1994, 25 (4), 181 and Chinese Journal of Pharmaceutical Industry, 2001, 32 (12), the method described in 557-8 is to carry out diazotization with fluoroboric acid, and acidify with hydrochloric acid after the reaction After extraction and crystallization, the yield is 55-66%. [0005] 3. The method described in the patent CN1461749 is that after the diazotization, the catalyst 4-lutidine is used in the copper s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D233/91
Inventor 杨欣欣袁振昌李烈全李宏松张淑娴廖春花
Owner WUHAN SYNCHALLENGE UNIPHARM INC
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