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Synthesis method of 3,6-dibromoimidazole[1,2-a]pyridine

A technology of dibromoimidazole and its synthesis method, which is applied in the direction of organic chemistry, can solve the problems of lack of literature and patent reports, high market price, and difficult synthesis, and achieve the effects of stable product quality, easy operation, and high purity

Inactive Publication Date: 2015-11-11
SHANDONG YOUBANG BIOCHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This product is a novel pharmaceutical intermediate with great medical value, but its synthesis is difficult, the market price is expensive, and there is a lack of literature and related patent reports

Method used

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  • Synthesis method of 3,6-dibromoimidazole[1,2-a]pyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Add 2-amino-5-bromopyridine (3.46g, 20mmol), 40% aqueous solution of chloroacetaldehyde (3.93g, 20mmol), potassium bicarbonate (1.68g, 20mmol) and 20mL (15.50 g) tert-butanol, start the magnetic stirrer, and the mixture in the reaction bottle was stirred and reacted at 82° C. for 5 hours. TLC detected the completion of the reaction of the raw material 2-amino-5-bromopyridine, added N-bromosuccinimide (3.56g, 20mmol), and reacted for another 4 hours under stirring at room temperature. The intermediate 6-bromoimidazole was determined by TLC and GC. And[1,2-a]pyridine reacts completely. Add water to the reaction solution, then suction filter the reaction solution, recrystallize the filter cake with ethyl acetate:n-hexane=1:3 to obtain the pure product 3,6-dibromoimidazo[1,2-a]pyridine, and use the filtrate Ethyl acetate extraction, rotary evaporation to remove the extractant to obtain the crude product, and then recrystallization with ethyl acetate: n-hexane = 1:3 to obta...

Embodiment 2

[0022] Add 2-amino-5-bromopyridine (17.30g, 100mmol), 40% aqueous solution of chloroacetaldehyde (19.63g, 100mmol), potassium bicarbonate (8.40g, 100mmol) and 150mL (117.9 g) acetonitrile, start the magnetic stirrer, and the mixture in the reaction bottle was stirred and reacted at 70° C. for 7.5 hours. TLC detected that the reaction of the raw material 2-amino-5-bromopyridine was completed, N-bromosuccinimide (17.80g, 100mmol) was added, and the reaction was continued for 4 hours under stirring at room temperature, and the intermediate 6-bromoimidazole was determined by TLC and GC. And[1,2-a]pyridine reacts completely. Add water to the reaction solution, then suction filter the reaction solution, recrystallize the filter cake with ethyl acetate:n-hexane=1:3 to obtain the pure product 3,6-dibromoimidazo[1,2-a]pyridine, and use the filtrate Ethyl acetate extraction, rotary evaporation to remove the extractant to obtain the crude product, and then recrystallization with ethyl a...

Embodiment 3

[0024] Add 2-amino-5-bromopyridine (51.90g, 300mmol), 40% aqueous solution of chloroacetaldehyde (70.65g, 360mmol), sodium bicarbonate (30.24g, 360mmol) and 150mL (135 g) ethyl acetate, start the magnetic stirrer, and the mixture in the reaction flask was stirred and reacted at 70° C. for 7.5 hours. TLC detected the completion of the reaction of the raw material 2-amino-5-bromopyridine, added N-bromosuccinimide (53.39g, 300mmol), and reacted for another 4 hours under stirring at room temperature. The intermediate 6-bromoimidazole was determined by TLC and GC. And[1,2-a]pyridine reacts completely. Add water to the reaction solution, then suction filter the reaction solution, recrystallize the filter cake with ethyl acetate:n-hexane=1:3 to obtain the pure product 3,6-dibromoimidazo[1,2-a]pyridine, and use the filtrate Ethyl acetate extraction, rotary evaporation to remove the extractant to obtain the crude product, and then recrystallization with ethyl acetate: n-hexane = 1:3 t...

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Abstract

The invention relates to a synthesis method of 3,6-dibromoimidazole[1,2-a]pyridine. In the synthesis method, 2-amino-5-bromopyridine, a water solution of chloroacetaldehyde, and N-bromosuccinimide are taken as the raw materials, the ratio of amount of substance of 2-amino-5-bromopyridine to chloroacetaldehyde is 1:0.85-2.4, the ratio of amount of substance of 2-amino-5-bromopyridine to N-bromosuccinimide is 1:0.9-3.1; the raw materials continuously react with each other in a proper solvent in the presence of alkali at a temperature of 25 to 95 DEG C to generate a coarse product of 3,6-dibromoimidazole[1,2-a]pyridine, and then the coarse product is purified to obtain a pure product of 3,6-dibromoimidazole[1,2-a]pyridine. The raw materials are easily-available, the prices are reasonable, at the same time, during the preparation, no heavy metal or corrosive gas is used, the reactions are mild, there is no special requirement on the equipment, production can be performed in common corrosion-resistant equipment, and moreover, the reaction conditions are mild.

Description

(1) Technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of 3,6-dibromoimidazo[1,2-a]pyridine. (2) Background technology [0002] On March 28, 2012, the preparation method of imidazo[1,2-a]pyridine derivatives, 6-bromoimidazo[1,2-a]pyridine was published, including: adding 400mL water, 15.5mL30~36 % concentrated hydrochloric acid, 120g bromoacetaldehyde diethyl acetal, then stirred at room temperature 10-30°C for 2.5 hours to obtain the hydrolyzed product bromoacetaldehyde; then add 72.8g sodium bicarbonate and 85g 2-amino- 5-bromopyridine, after reacting at room temperature for 18 hours, stand still and separate the phases into an aqueous phase and an organic phase; wherein the aqueous phase is extracted with ethyl acetate, and after the extract is combined with the organic phase after standing still, use anhydrous Dry over sodium sulfate, filter, concentrate to dryness, and recrystallize the concen...

Claims

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Application Information

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IPC IPC(8): C07D471/04
CPCC07D471/04
Inventor 耿宣平韩猛来新胜曹惊涛
Owner SHANDONG YOUBANG BIOCHEM TECH