Synthesis method of 6-bromoimidazo[1,2-alpha]pyridyl-3-formic acid

A synthetic method, 2-a technology, applied in the direction of organic chemistry, etc., can solve the problems of many by-products, expensive, cumbersome operation, etc., and achieve the effects of mild reaction conditions, stable product quality, and simple post-treatment

Inactive Publication Date: 2014-08-06
SHANDONG YOUBANG BIOCHEM TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify
Although it can be recrystallized multiple times with organic solvents, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation;
[0005] (2) The chemical reduction method used has serious corrosion of equipment and environmental pollution, and its development has been restricted at present;
[0006] (3) The source of raw materials is limited, the price is expensive, and the operation is troublesome;
[0007] (4) Need to use noble metal catalyst, increased preparation cost

Method used

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  • Synthesis method of 6-bromoimidazo[1,2-alpha]pyridyl-3-formic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] 80mL (71.7g) of N,N-dimethylformamide dimethyl acetal is both solvent and reaction raw material, react with 2-amino-5-bromopyridine (34.6g, 200mmol) at 70°C for 5 hours, and the reaction ends Prepare N,N-dimethyl-N'-2-(5-bromo-pyridinyl)-formamidine intermediate, remove excess N,N-dimethylformamide dimethyl acetal by rotary evaporation, add 120 mL (125 g) dioxane, NaHCO 3 (25.2g, 300mmol) and ethyl bromoacetate (50.1g, 300mmol), react at 80°C for 10 hours, after the reaction is completed, cool to room temperature, add 600 mL of water and 200 mL of ethyl acetate for extraction, separate the organic phase and the aqueous phase Extract with ethyl acetate (3×200 mL), combine the organic phases, wash with water (2×150 mL), wash with 200 mL saturated brine, anhydrous Na 2 SO 4 Dry, filter, and concentrate the filtrate to obtain the crude product of ethyl 6-bromoimidazo[1,2-a]pyridine-3-carboxylate, which is mixed with n-hexane:ethyl acetate=3:1 (volume ratio) The solution ...

Embodiment 2

[0030] 80mL (71.7g) of N,N-dimethylformamide dimethyl acetal is both a solvent and a reaction raw material, react with 2-amino-5-bromopyridine (34.6g, 200mmol) at 70°C for 5 hours, and the reaction ends Prepare N,N-dimethyl-N'-2-(5-bromo-pyridinyl)-formamidine intermediate, remove excess N,N-dimethylformamide dimethyl acetal by rotary evaporation, add 120 mL (103 g) toluene, K 2 CO 3 (20.8g, 150mmol) and ethyl bromoacetate (50.1g, 300mmol), react at 80°C for 10 hours, after the reaction is completed, cool to room temperature, add 600 mL of water and 200 mL of ethyl acetate for extraction, separate the organic phase and the aqueous phase Extract with ethyl acetate (3×200 mL), combine the organic phases, wash with water (2×150 mL), wash with 200 mL saturated brine, anhydrous Na 2 SO 4 Dry, filter, and concentrate the filtrate to obtain the crude product of ethyl 6-bromoimidazo[1,2-a]pyridine-3-carboxylate, which is mixed with n-hexane:ethyl acetate=3:1 (volume ratio) The sol...

Embodiment 3

[0033] N,N-Dimethylformamide dimethyl acetal (80mL) is both a solvent and a reaction raw material, reacted with 2-amino-5-bromopyridine (34.6g, 200mmol) at 60°C for 8 hours, and the reaction was completed N,N-Dimethyl-N'-2-(5-bromo-pyridinyl)-formamidine intermediate, rotary evaporation to remove excess N,N-dimethylformamide dimethyl acetal, add 120 mL (114g) N,N-dimethylformamide (DMF), triethylamine (30.3g, 300mmol) and ethyl bromoacetate (50.1g, 300mmol), react at 100°C for 8 hours, after the reaction is complete, cool to room temperature , add 600 mL of water and 200 mL of ethyl acetate for extraction, separate the organic phase, extract the water phase with ethyl acetate (3×200 mL), combine the organic phases, wash with water (2×150 mL), and 200 mL of saturated saline Wash, anhydrous Na 2 SO 4 Dry, filter, and concentrate the filtrate to obtain the crude product of ethyl 6-bromoimidazo[1,2-a]pyridine-3-carboxylate, which is mixed with n-hexane:ethyl acetate=3:1 (volume ...

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a synthesis method of 6-bromoimidazo[1,2-alpha]pyridyl-3-formic acid. The method comprises the following steps: reacting N,N-dimethylformamidodimethyl acetal with 2-amino-5-bromopyridine at 40-100 DEG C to obtain an intermediate, and reacting the intermediate with ethyl bromoacetate at 60-160 DEG C for 3-15 hours; after the reaction finishes, cooling to room temperature, and concentrating by rotary evaporation to obtain an ethyl 6-bromoimidazo[1,2-alpha]pyridyl-3-formate crude product; and under the action of an alkali, carrying out hydrolysis reaction on the ethyl 6-bromoimidazo[1,2-alpha]pyridyl-3-formate in a certain solvent for 1-5 hours, neutralizing with hydrochloric acid, filtering, washing with water, and drying to directly obtain the 6-bromoimidazo[1,2-alpha]pyridyl-3-formic acid pure product. The method has the advantages of accessible reaction raw materials, reasonable price, mild reaction conditions and simple after-treatment, and is easy to operate and control; and the product has the advantages of stable quality and high purity.

Description

(1) Technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a synthesis method of 6-bromoimidazo[1,2-a]pyridine-3-carboxylic acid. (2) Background technology [0002] 6-Bromoimidazo[1,2-a]pyridine-3-carboxylic acid is an important intermediate in organic synthesis, mainly used in pharmaceutical intermediates, organic synthesis, organic solvents, and can also be used in dye production, pesticide production and spices, etc. aspect. [0003] The preparation of existing 6-bromoimidazo[1,2-a]pyridine-3-carboxylic acid has the following disadvantages: [0004] (1) There are many by-products, resulting in a darker color of the product, which is difficult to refine and purify. Although organic solvents can be used to recrystallize multiple times, the quality still cannot meet the high requirements, and repeated crystallization leads to low product yield, increased cost, and cumbersome operation; [0005] (2) The chemical reducti...

Claims

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Application Information

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IPC IPC(8): C07D471/04
CPCC07D471/04
Inventor 樊红莉李鑫来新胜曹惊涛
Owner SHANDONG YOUBANG BIOCHEM TECH
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