Method for synthesizing N-(3,4-dimethoxybenzyl)amide capsaicine homologous compounds

Abstract

The invention relates to a method for synthesizing N-(3,4-dimethoxybenzyl)amide capsaicine homologous compounds the general structural formula of which are shown in formula (1), wherein R is alkyl group, naphthenic base or aromatic base the carbon atomic number of which is between 1 and 20. Compared with the existing synthetic method that reagent dimethyl sulfate with toxicity or iodomethane with toxicity and expensive price is used as a methylation regent in the process of synthesizing the compounds, the method of the invention has the maximal advantages that cheap and nontoxic dimethyl carbonate is used as the methylation regent, the reaction conditions are mild and the yield is high.

Description

technical field

[0001] The invention relates to a chemical synthesis method of capsaicin homologues, in particular to a chemical synthesis method of N-(3,4-dimethoxybenzyl) amides capsaicin homologues. Background technique

[0002] The fruit of the capsicum plant (capsicum genus) is one of the most consumed condiments worldwide. These pepper fruits contain at least 15 kinds of capsaicinoids that can produce a spicy taste. Among them, capsaicin (46%~69%), dihydrocapsaicin (21%~40%), nordihydrocapsaicin (~7%), homodihydrocapsaicin (~1%), homocapsaicin (~ 1%), and the remaining capsaicinoids are trace amounts. Capsaicin is the most spicy, as high as 16,000,000 Scoville Heat Unit (SHU); followed by dihydrocapsaicin, which is 15,000,000SHU; 8,6000,000 SHU.

[0003] Capsaicin has various pharmacological effects due to its pungent taste, such as analgesia, anti-inflammation, treatment of frostbite, antipruritic, sterilization, rheumatism, etc.; it is mainly used clinically to t...

Examples

Embodiment 1

[0035] (1) Synthesis of vanillin aldoxime

[0036] Dissolve 7.6g of vanillin in 50mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 4.2g of hydroxylamine hydrochloride and 2.4g of sodium hydroxide. After the dropwise addition was completed, the reaction was incubated at 70° C. for 3 h. Cool to room temperature, filter, and distill the filtrate to remove the solvent under reduced pressure. Then 50 mL of ether was added, and the ether phase was washed with deionized water. The aqueous phase was removed, and the ether phase was dried over anhydrous sodium sulfate. Filter to obtain anhydrous ether solution of vanillin aldoxime.

[0037] (2) Synthesis of vanillylamine hydrochloride

[0038] Add 5.6g of lithium aluminum hydride and about 300mL of anhydrous ether into a 500mL three-neck flask, then add 4-hydroxy-3-methoxybenzaldehyde oxime anhydrous ether solution dropwise, and react at room temperature for 12 hours after the addition is complete. ...

Embodiment 2

[0045] (1) Synthesis of vanillin aldoxime

[0046] Dissolve 15.2g of vanillin in 80mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 8.0g of hydroxylamine hydrochloride and 4.5g of sodium hydroxide. After the dropwise addition was completed, the reaction was incubated at 70° C. for 3 h. Cool to room temperature, filter, and distill the filtrate to remove the solvent under reduced pressure. Then 60 mL of ether was added, and the ether phase was washed with deionized water. The aqueous phase was removed, and the ether phase was dried over anhydrous sodium sulfate. After filtration, the filtrate was distilled off under reduced pressure to remove ether, and 14.8 g of vanillin aldoxime solid powder was obtained, with a yield of 89%.

[0047] (2) Synthesis of vanillylamine hydrochloride

[0048] In a 250mL three-necked reaction flask, add 8.4g of 4-hydroxy-3-methoxybenzaldehyde oxime, 150mL of absolute ethanol, 15mL of concentrated hydrochloric ac...

Embodiment 3

[0055] (1) Synthesis of 3,4-dimethoxybenzaldehyde

[0056] Add 16.0 g of vanillin, 12.2 g of tetramethylammonium bromide, 10.5 g of potassium carbonate, and 100 mL of dimethyl carbonate into a 250 mL three-necked flask, and react under reflux for 8 hours. Cool down to room temperature, filter, adjust the pH of the filtrate to 1-2 with dilute hydrochloric acid, and then extract with methyl tert-butyl ether for 3 times. The extracts were combined, washed successively with 1N NaOH solution and saturated brine, and dried over anhydrous sodium sulfate. Filter and distill off methyl tert-butyl ether under reduced pressure to obtain 4.2 g of 3,4-dimethoxybenzaldehyde with a yield of 24%.

[0057] (2) Synthesis of 3,4-dimethoxybenzaldehyde oxime

[0058] Dissolve 4.2g of 3,4-dimethoxybenzaldehyde in 25mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 2.1g of hydroxylamine hydrochloride and 1.2g of sodium hydroxide. After the dropwise addition was com...

technical field

[0001] The invention relates to a chemical synthesis method of capsaicin homologues, in particular to a chemical synthesis method of N-(3,4-dimethoxybenzyl) amides capsaicin homologues. Background technique

[0002] The fruit of the capsicum plant (capsicum genus) is one of the most consumed condiments worldwide. These pepper fruits contain at least 15 kinds of capsaicinoids that can produce a spicy taste. Among them, capsaicin (46%~69%), dihydrocapsaicin (21%~40%), nordihydrocapsaicin (~7%), homodihydrocapsaicin (~1%), homocapsaicin (~ 1%), and the remaining capsaicinoids are trace amounts. Capsaicin is the most spicy, as high as 16,000,000 Scoville Heat Unit (SHU); followed by dihydrocapsaicin, which is 15,000,000SHU; 8,6000,000 SHU.

[0003] Capsaicin has various pharmacological effects due to its pungent taste, such as analgesia, anti-inflammation, treatment of frostbite, antipruritic, sterilization, rheumatism, etc.; it is mainly used clinically to t...

Examples

Embodiment 1

[0035] (1) Synthesis of vanillin aldoxime

[0036] Dissolve 7.6g of vanillin in 50mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 4.2g of hydroxylamine hydrochloride and 2.4g of sodium hydroxide. After the dropwise addition was completed, the reaction was incubated at 70° C. for 3 h. Cool to room temperature, filter, and distill the filtrate to remove the solvent under reduced pressure. Then 50 mL of ether was added, and the ether phase was washed with deionized water. The aqueous phase was removed, and the ether phase was dried over anhydrous sodium sulfate. Filter to obtain anhydrous ether solution of vanillin aldoxime.

[0037] (2) Synthesis of vanillylamine hydrochloride

[0038] Add 5.6g of lithium aluminum hydride and about 300mL of anhydrous ether into a 500mL three-neck flask, then add 4-hydroxy-3-methoxybenzaldehyde oxime anhydrous ether solution dropwise, and react at room temperature for 12 hours after the addition is complete. ...

Embodiment 2

[0045] (1) Synthesis of vanillin aldoxime

[0046] Dissolve 15.2g of vanillin in 80mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 8.0g of hydroxylamine hydrochloride and 4.5g of sodium hydroxide. After the dropwise addition was completed, the reaction was incubated at 70° C. for 3 h. Cool to room temperature, filter, and distill the filtrate to remove the solvent under reduced pressure. Then 60 mL of ether was added, and the ether phase was washed with deionized water. The aqueous phase was removed, and the ether phase was dried over anhydrous sodium sulfate. After filtration, the filtrate was distilled off under reduced pressure to remove ether, and 14.8 g of vanillin aldoxime solid powder was obtained, with a yield of 89%.

[0047] (2) Synthesis of vanillylamine hydrochloride

[0048] In a 250mL three-necked reaction flask, add 8.4g of 4-hydroxy-3-methoxybenzaldehyde oxime, 150mL of absolute ethanol, 15mL of concentrated hydrochloric ac...

Embodiment 3

[0055] (1) Synthesis of 3,4-dimethoxybenzaldehyde

[0056] Add 16.0 g of vanillin, 12.2 g of tetramethylammonium bromide, 10.5 g of potassium carbonate, and 100 mL of dimethyl carbonate into a 250 mL three-necked flask, and react under reflux for 8 hours. Cool down to room temperature, filter, adjust the pH of the filtrate to 1-2 with dilute hydrochloric acid, and then extract with methyl tert-butyl ether for 3 times. The extracts were combined, washed successively with 1N NaOH solution and saturated brine, and dried over anhydrous sodium sulfate. Filter and distill off methyl tert-butyl ether under reduced pressure to obtain 4.2 g of 3,4-dimethoxybenzaldehyde with a yield of 24%.

[0057] (2) Synthesis of 3,4-dimethoxybenzaldehyde oxime

[0058] Dissolve 4.2g of 3,4-dimethoxybenzaldehyde in 25mL of absolute ethanol and heat to 70°C, then add dropwise an aqueous solution of 2.1g of hydroxylamine hydrochloride and 1.2g of sodium hydroxide. After the dropwise addition was com...

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