5-bromo-2-furfural synthesis method

Abstract

The invention relates to the organic synthesis field, and especially discloses a 5-bromo-2-furfural synthesis method. The 5-bromo-2-furfural synthesis method which treats furfural and bromine as raw materials is characterized in that the method comprises the following steps: placing the raw materials in an aprotic solvent, reacting at 25-70DEG C for 2-24h under the initiation of resorcinol and sulfur, concentrating, washing, drying to obtain an oily product, processing the oily product by using a mixed solution comprising water and alcohol to obtain a crude product, and recrystallizing to obtain pure 5-bromo-2-furfural. The method has the advantages of reasonable selection of the reaction technology, mild product condition, simple operation, stable product quality, high product purity, and avoiding of the aldehyde group protection and deprotection, and the separation and purification of an intermediate in a multistep reaction.

Description

(1) Technical field

[0001] The invention relates to the field of organic synthesis, in particular to a synthesis method of 5-bromo-2-furancarbaldehyde. (2) Background technology

[0002] 5-bromo-2-furfural, also known as 5-bromofurfural, is an important intermediate in organic synthesis. Because its molecule contains bifunctional groups -Br and -CHO, it is an important molecular building block for the research and development of medicine and pesticides.

[0003] The traditional preparation method of 5-bromo-2-furfuraldehyde is that after the aldehyde group of 2-furfuraldehyde is protected by acylation, it is nitrated under the action of concentrated nitric acid to generate 5-nitro-2-furfuraldehyde, then brominated, and then Deprotection in acidic medium gives 5-bromo-2-furfuraldehyde in three steps.

[0004] There are also records in the literature that 5-bromo-2-furancarbaldehyde is prepared by one-step method, but it is a photochemical reaction, which is difficult to...

Examples

Embodiment 1

[0016] Add 1,2-dichloroethane (240 ml) into a 2000 ml two-neck round bottom flask, then add furfural (49.6 ml, 600 mmol), hydroquinone (0.6 g, 5.2 mmol) and sulfur powder in sequence (0.168 g, 5.2 mmol). 1,2-Dichloroethane (300ml) and liquid bromine (36.8ml, 680mmol) were added to a constant pressure funnel. After the mixture in the reaction flask is heated to reflux, slowly add the bromine solution in 1,2-dichloroethane into the reaction flask (1~3 hours to complete the addition), and the reaction mixture is heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH = 8, separate the organic phase, extract the aqueous phase with dichloromethane (3 × 75ml), combine the organic phases with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to...

Embodiment 2

[0018] Add dichloromethane (60 ml) into a 250 ml two-neck flask, then add furfural (12.4 ml, 150 mmol), hydroquinone (0.15 g, 1.3 mmol) and sulfur powder (0.042 g, 1.3 mmol) in sequence . 1,2-Dichloroethane (75ml) and liquid bromine (9.2ml, 170mmol) were added to a constant pressure funnel. After the mixture in the reaction flask was heated to reflux, a solution of bromine in dichloromethane was slowly added to the reaction flask (completed in 3 hours), and the reaction mixture was heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH=8, separate the organic phase, extract the aqueous phase with dichloromethane (2×50ml), combine the organic phases and wash with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to obtain 7.73 g of orang...

Embodiment 3

[0020] 1,2-Dichloroethane (60 mL) was added to a 250 mL two-neck flask, followed by furfural (12.4 mL, 150 mmol) and hydroquinone (0.15 g, 1.3 mmol). 1,2-Dichloroethane (75ml) and liquid bromine (9.2ml, 170mmol) were added to a constant pressure funnel. After the mixture in the reaction flask was heated to reflux, the solution of bromine in 1,2-dichloroethane was slowly added into the reaction flask (the addition was completed in 3 hours), and the reaction mixture was heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH = 8, separate the organic phase, extract the aqueous phase with dichloromethane (3 × 75ml), combine the organic phases with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to obtain 1.3 g of orange needle-like crystal...

(1) Technical field

[0001] The invention relates to the field of organic synthesis, in particular to a synthesis method of 5-bromo-2-furancarbaldehyde. (2) Background technology

[0002] 5-bromo-2-furfural, also known as 5-bromofurfural, is an important intermediate in organic synthesis. Because its molecule contains bifunctional groups -Br and -CHO, it is an important molecular building block for the research and development of medicine and pesticides.

[0003] The traditional preparation method of 5-bromo-2-furfuraldehyde is that after the aldehyde group of 2-furfuraldehyde is protected by acylation, it is nitrated under the action of concentrated nitric acid to generate 5-nitro-2-furfuraldehyde, then brominated, and then Deprotection in acidic medium gives 5-bromo-2-furfuraldehyde in three steps.

[0004] There are also records in the literature that 5-bromo-2-furancarbaldehyde is prepared by one-step method, but it is a photochemical reaction, which is difficult to...

Examples

Embodiment 1

[0016] Add 1,2-dichloroethane (240 ml) into a 2000 ml two-neck round bottom flask, then add furfural (49.6 ml, 600 mmol), hydroquinone (0.6 g, 5.2 mmol) and sulfur powder in sequence (0.168 g, 5.2 mmol). 1,2-Dichloroethane (300ml) and liquid bromine (36.8ml, 680mmol) were added to a constant pressure funnel. After the mixture in the reaction flask is heated to reflux, slowly add the bromine solution in 1,2-dichloroethane into the reaction flask (1~3 hours to complete the addition), and the reaction mixture is heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH = 8, separate the organic phase, extract the aqueous phase with dichloromethane (3 × 75ml), combine the organic phases with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to...

Embodiment 2

[0018] Add dichloromethane (60 ml) into a 250 ml two-neck flask, then add furfural (12.4 ml, 150 mmol), hydroquinone (0.15 g, 1.3 mmol) and sulfur powder (0.042 g, 1.3 mmol) in sequence . 1,2-Dichloroethane (75ml) and liquid bromine (9.2ml, 170mmol) were added to a constant pressure funnel. After the mixture in the reaction flask was heated to reflux, a solution of bromine in dichloromethane was slowly added to the reaction flask (completed in 3 hours), and the reaction mixture was heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH=8, separate the organic phase, extract the aqueous phase with dichloromethane (2×50ml), combine the organic phases and wash with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to obtain 7.73 g of orang...

Embodiment 3

[0020] 1,2-Dichloroethane (60 mL) was added to a 250 mL two-neck flask, followed by furfural (12.4 mL, 150 mmol) and hydroquinone (0.15 g, 1.3 mmol). 1,2-Dichloroethane (75ml) and liquid bromine (9.2ml, 170mmol) were added to a constant pressure funnel. After the mixture in the reaction flask was heated to reflux, the solution of bromine in 1,2-dichloroethane was slowly added into the reaction flask (the addition was completed in 3 hours), and the reaction mixture was heated and stirred to reflux for 20 hours. After the reaction, cool to room temperature, filter, and neutralize the filtrate with saturated sodium bicarbonate solution to pH = 8, separate the organic phase, extract the aqueous phase with dichloromethane (3 × 75ml), combine the organic phases with anhydrous sulfuric acid Sodium dry. The solvent was removed by rotary evaporation to obtain a black oil, which was added to a 1:1 solution of water and ethanol with stirring to obtain 1.3 g of orange needle-like crystal...