Synthetic method of L-nicotine with optical activity

Abstract

L-nicotine with optical activity is synthesized by adopting a one-pot method, an intermediate-L-nornicotine with optical activity is obtained from myosmine in a reduction system with hydrogen as a reducing agent and a chiral ligand / iridium metal catalyst, L-nornicotine is not subjected to post-treatment and is subjected to an aminomethylation reaction through a pyrrole ring, alkali is added into a product to adjust the pH value to 12-13.5, extracting is conducted with an organic solvent, separating, drying and concentrating are conducted to obtain a crude product, and silica gel column chromatography is conducted to obtain a high-purity product, namely the final product, namely the L-nicotine. According to the method, asymmetric hydrogenation of the myosmine is a key step of the method, the asymmetric hydrogenation reaction is catalyzed by an iridium-phosphorus oxazoline catalyst, the key intermediate L-nornicotine can be obtained at a high ee value, and the target product L-nicotine is obtained through an aminomethylation reaction and a one-pot method without subsequent purification treatment. According to the present invention, the method has advantages of low cost, stable operation and high purity.

Description

technical field

[0001] The invention relates to the technical field of compound preparation, and specifically adopts a one-pot method to synthesize L-nicotine with optical activity. Background technique

[0002] L-nicotine, also known as nicotine, is a naturally occurring chiral alkaloid, the main component of tobacco alkaloids, and is widely used in the fields of medicine and pesticides. At present, L-nicotine on the market is mainly extracted and purified from herbs and other plants, but limited by factors such as raw materials, land resources, cycle and separation technology, there is a strong demand for high-purity and high-optical-purity nicotine in the market, which is why It is necessary to develop an effective chemical synthesis method to prepare L-nicotine, which is suitable for large-scale industrial production.

[0003] At present, the vast majority of chemically synthesized L-nicotine is obtained by first synthesizing racemic nicotine and then performing chiral ...

Examples

Embodiment 1

[0030] Add mesmin (0.5mmol) and iridium-phosphoroxazoline catalyst (0.005mmol) in the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 4ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 5 ml of toluene, formic acid (1 mmol), and paraformaldehyde (0.6 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 13, and water was added until the solid dissolved. Extract three times with ethyl acetate, combine organic phase, dry, rotary evaporate to obtain crude product, obtain the L-nicotine (99%ee) of light yellow oily liquid with the productive rate of 68% with silica gel column chromatography, product H NMR spectrum Such as figure 1 As shown, the carbon NMR spectrum is as figure 2 As shown, the chromatogram is shown as image 3 shown. 1 H NMR (600MHz, CDCl 3 ), δ=8.53(d, J=1.9Hz, 1H), 8.50(dd,...

Embodiment 2

[0032] Add mesmin (1.0mmol) and iridium-phosphoroxazoline catalyst (0.01mmol) into the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 7ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 10 ml of toluene, formic acid (2 mmol), and paraformaldehyde (1.2 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 12, and water was added until the solid dissolved. Extracted three times with ethyl acetate, combined the organic phases, dried, and rotary evaporated to obtain the crude product, and obtained the light yellow oily liquid L-nicotine (98.5% ee) with a yield of 65% by silica gel column chromatography.

Embodiment 3

[0034] Add mesmin (1.5mmol) and iridium-phosphoroxazoline catalyst (0.015mmol) into the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 10ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 10 ml of toluene, formic acid (3 mmol), and paraformaldehyde (1.8 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 13.5, and water was added until the solid dissolved. Extracted three times with ethyl acetate, combined the organic phases, dried, and rotary evaporated to obtain the crude product, and obtained light yellow oily liquid L-nicotine (97% ee) with a yield of 64% by silica gel column chromatography.

technical field

[0001] The invention relates to the technical field of compound preparation, and specifically adopts a one-pot method to synthesize L-nicotine with optical activity. Background technique

[0002] L-nicotine, also known as nicotine, is a naturally occurring chiral alkaloid, the main component of tobacco alkaloids, and is widely used in the fields of medicine and pesticides. At present, L-nicotine on the market is mainly extracted and purified from herbs and other plants, but limited by factors such as raw materials, land resources, cycle and separation technology, there is a strong demand for high-purity and high-optical-purity nicotine in the market, which is why It is necessary to develop an effective chemical synthesis method to prepare L-nicotine, which is suitable for large-scale industrial production.

[0003] At present, the vast majority of chemically synthesized L-nicotine is obtained by first synthesizing racemic nicotine and then performing chiral ...

Examples

Embodiment 1

[0030] Add mesmin (0.5mmol) and iridium-phosphoroxazoline catalyst (0.005mmol) in the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 4ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 5 ml of toluene, formic acid (1 mmol), and paraformaldehyde (0.6 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 13, and water was added until the solid dissolved. Extract three times with ethyl acetate, combine organic phase, dry, rotary evaporate to obtain crude product, obtain the L-nicotine (99%ee) of light yellow oily liquid with the productive rate of 68% with silica gel column chromatography, product H NMR spectrum Such as figure 1 As shown, the carbon NMR spectrum is as figure 2 As shown, the chromatogram is shown as image 3 shown. 1 H NMR (600MHz, CDCl 3 ), δ=8.53(d, J=1.9Hz, 1H), 8.50(dd,...

Embodiment 2

[0032] Add mesmin (1.0mmol) and iridium-phosphoroxazoline catalyst (0.01mmol) into the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 7ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 10 ml of toluene, formic acid (2 mmol), and paraformaldehyde (1.2 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 12, and water was added until the solid dissolved. Extracted three times with ethyl acetate, combined the organic phases, dried, and rotary evaporated to obtain the crude product, and obtained the light yellow oily liquid L-nicotine (98.5% ee) with a yield of 65% by silica gel column chromatography.

Embodiment 3

[0034] Add mesmin (1.5mmol) and iridium-phosphoroxazoline catalyst (0.015mmol) into the Schlenk tube protected by nitrogen, replace the nitrogen in the Schlenk tube with hydrogen, add 10ml of 1,2-dichloroethane, and Under reaction for 24 hours. After spin-drying the solvent, 10 ml of toluene, formic acid (3 mmol), and paraformaldehyde (1.8 mmol) were added, and stirred at 65° C. for 3 hours. After the reaction was complete, aqueous NaOH solution was added to adjust the pH of the mixture to 13.5, and water was added until the solid dissolved. Extracted three times with ethyl acetate, combined the organic phases, dried, and rotary evaporated to obtain the crude product, and obtained light yellow oily liquid L-nicotine (97% ee) with a yield of 64% by silica gel column chromatography.

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