Preparation method of 4-iodo-1H-imidazole

A technology of imidazole and recrystallization, applied in the field of new synthesis of pharmaceutical intermediates, can solve the problems of high environmental pressure, high cost, poor reaction atom economy, etc., and achieves reduction in proportion, cost reduction, and generation of polluting wastes. Effect

Inactive Publication Date: 2020-03-31
CHINA PHARM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The atom economy of this method is poor, and the reaction process needs to consume a large amount of iodine, sodium iodide and potassium sulfite, and potassium sulfite can actually reduce 4-iodo-1H-imidazole, so the yield will be reduced
In addition, the reduction will produce a large amount of waste liquid containing potassium sulfite, and the pressure on environmental protection is relatively high.
[0003] The traditional preparation method of 4-iodo-1H-imidazole has the disadvantages of large demand for raw materials, high cost and poor reaction atom economy

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Sodium hydroxide (24.0 g, 0.60 mol) was dissolved in 150 mL of water, and the temperature was lowered to room temperature, then imidazole (40.8 g, 0.60 mol) was added and stirred to dissolve. Sodium iodide (33.8 g, 0.23 mol) was dissolved in 45 mL of water, the temperature was lowered to room temperature, and then iodine (38.1 g, 0.15 mol) was added. At 0°C, add iodine and sodium iodide aqueous solutions dropwise to sodium hydroxide and imidazole aqueous solutions, and react at 0°C for 6 hours after the addition is complete. After the reaction, the pH was adjusted to 7-8 with concentrated hydrochloric acid, a solid was precipitated, and 17.1 g of a white solid was obtained by suction filtration and drying. Add 50 grams of sodium chloride to the filtrate to saturation, extract with 300 mL of ethyl acetate × 2, combine the organic layers, and concentrate to dryness under reduced pressure to obtain 19 grams of light yellow solid. A mixed solvent of n-hexane was used for r...

Embodiment 2

[0025] Sodium hydroxide (190 g, 4.73 mol) was dissolved in 800 mL of water, and the temperature was lowered to room temperature, then imidazole (320 g, 4.73 mol) was added and stirred to dissolve. Sodium iodide (265 g, 1.77 mol) was dissolved in 200 mL of water, the temperature was lowered to room temperature, and then iodine (300 g, 1.18 mol) was added. At 0°C, add iodine and sodium iodide aqueous solutions dropwise to the sodium hydroxide and imidazole aqueous solutions, and react at 0°C for 10 hours after the dropwise addition is complete. After the reaction, the pH was adjusted to 7-8 with concentrated hydrochloric acid, a solid was precipitated, and 130 g of a white solid was obtained by suction filtration and drying. The filtrate was extracted with 500 mL of ethyl acetate × 3, the combined organic layers were concentrated to dryness under reduced pressure to obtain 148 g of a light yellow solid, which was recrystallized with a mixed solvent containing 100 mL of ethyl ace...

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PUM

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Abstract

The invention provides a preparation method of 4-iodo-1H-imidazole. The preparation method comprises the following steps: (1) enabling imidazole, iodine and a cosolvent for promoting the solubility ofiodine in water to react under an alkaline condition in the presence of water as a solvent, after the reaction is finished, adjusting the pH value to 7-9, filtering out precipitated white solids, performing extraction, reduced pressure distillation to remove the solvent, and recrystallization on the filtrate to recover imidazole, concentrating the recrystallized mother liquor, and mixing the obtained white solids and the precipitated white solids to obtain a 4-iodo-1H-imidazole crude product, and (2) recrystallizing the 4-iodo-1H-imidazole crude product twice to obtain a white crystal 4-iodo-1H-imidazole pure product. The method has the advantages of simple process, high reaction yield, low production cost and recyclable raw materials.

Description

technical field [0001] The invention relates to a new synthesis process of a pharmaceutical intermediate, in particular to a preparation method of 4-iodo-1H-imidazole. Background technique [0002] In the pharmaceutical industry, the imidazole group is an important structural component of many bioactive molecules. For example, many compounds with affinity for histamine receptors contain an imidazole moiety. Using 4-iodo-1H-imidazole, imidazole groups can be introduced into different molecules through Suzuki reaction, so the development of an effective new synthesis process of 4-iodo-1H-imidazole has a wide range of practical applications and high economic value. The traditional preparation method of 4-iodo-1H-imidazole has the following several methods: (1) react with imidazole, iodine monochloride and potassium chloride to obtain 4-iodo-1H-imidazole. However, iodine monochloride not only has strong oxidizing properties, but also reacts with water to release heat and produ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D233/68
CPCC07D233/68
Inventor 孙海鹰方坤森马宗辉李联伟
Owner CHINA PHARM UNIV
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