Tocopherol derivatives and preparation methods and applications thereof

Abstract

The present invention provides a tocopherol derivative, a preparation method, and applications thereof. The tocopherol derivative is characterized by a compound having the following structure: #imgabs0#, where R' is hydrogen or acetyl. The tocopherol derivative is obtained by esterifying theanine with tocopherol in the presence of a catalyst and a co-catalyst. The compound can be used as an antioxidant additive in cosmetics, food and health supplements, pet products, and the like. The method features mild reaction conditions, simple operation, high yield, and efficient synthesis, and is economical and environmentally friendly, demonstrating promising application prospects.

Description

Technical Field

[0001] The present invention relates to a new chemical and a preparation method thereof, in particular to a tocopherol derivative and a catalytic synthesis method and application thereof. Background Art

[0002] Tocopherol and theanine have attracted widespread attention in the industry for their antioxidant properties. Combining them could yield a product with unexpected benefits.

[0003] However, according to the reaction conditions of phenol and acid in the existing similar technology, theanine and tocopherol are condensed in tetrahydrofuran to obtain the synthetic product. However, during the reaction process, it was found that this scheme not only has harsh reaction conditions but also has poor yield and purity.

[0004] According to the reaction conditions of phenol and acid in another existing similar technology, the acyl chloride compound of theanine and tocopherol are condensed to obtain the synthetic product. However, during the reaction process, it was found that the reaction conditions were also harsh and the yield and purity were poor.

[0005] Therefore, there is an urgent need to develop a synthetic product based on tocopherol and theanine, as well as a synthetic method for the product that is efficient and energy-saving and reduces the unsafe and toxic problems in the production process. Summary of the Invention

[0006] The present invention aims to provide a tocopherol derivative synthesized from tocopherol and theanine. This method addresses the drawbacks of conventional phenolic acid reactions, such as low economic efficiency, harsh reaction conditions, and complex procedures, and provides a novel method for preparing tocopherol derivatives. This method features mild reaction conditions, simple operation, high yield, high synthesis efficiency, and is economical and environmentally friendly, with promising application prospects.

[0007] Specifically, the present invention provides a tocopherol derivative, characterized by being a compound shown in the following structure:

[0008]

[0009] R' is hydrogen or acetyl.

[0010] The most preferred R' is hydrogen. Based on the considerations of product stability, application and diversification, this can be achieved by replacing one hydrogen of NH2 with an acetyl group.

[0011] It can be used as an antioxidant and used as an antioxidant additive in cosmetics, food health products, pet products, etc.

[0012] The present invention also provides a method for preparing the above-mentioned tocopherol derivative, which is characterized by:

[0013] Theanine and tocopherol are esterified under the action of a catalyst and a co-catalyst to obtain a tocopherol derivative;

[0014] The catalyst is selected from the compounds shown in the following structures:

[0015]

[0016] R, R1 are the same or different alkyl or aryl groups.

[0017] The specific reaction equation is shown below:

[0018]

[0019] In the above catalysts, preferably R and R1 are Me, n-Bu, Ph;

[0020] The most preferred catalyst can be selected from the following compounds:

[0021]

[0022] The reaction mechanism of the catalyst in the preparation of tocopherol derivatives is as follows: the acidic hydrogen of the cationic part of the catalyst is used as a hydrogen bond donor to activate the carbonyl group of theanine, while the oxygen anion of the anionic part of the catalyst can act as a hydrogen bond acceptor to activate the phenolic hydroxyl group on tocopherol, thereby promoting the esterification reaction.

[0023] Taking catalyst cat.1 as an example, the activation mechanism of the reaction can be described as follows:

[0024]

[0025] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is also characterized in that the molar amount of the catalyst added is 0.2-0.5% of the total molar amount of the reactants, preferably 0.2-0.4%, most preferably 0.2-0.3%.

[0026] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is characterized in that the molar ratio of theanine to tocopherol is 1-1.5:1, preferably 1.2-1.5:1, and most preferably 1.4-1.5:1.

[0027] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is characterized in that the co-catalyst is sodium phosphate, which acts as an activating catalyst.

[0028] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is also characterized in that the molar ratio of the above-mentioned co-catalyst to theanine is 0.1-0.5:1, preferably 0.1-0.3:1, and most preferably 0.1-0.2:1.

[0029] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is characterized by: mixing theanine, tocopherol, a co-catalyst and a catalyst, stirring and reacting at room temperature for 4-6 hours, and purifying the product through post-treatment.

[0030] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is also characterized in that: the reaction is carried out under solvent conditions;

[0031] The above-mentioned solvent is selected from one or more of halogenated alkanes (such as dichloromethane, chloroform, etc.), ethers (such as tetrahydrofuran, dioxane, tert-butyl methyl ether, diethyl ether, etc.), nitriles (such as acetonitrile, etc.), amides (such as N,N-dimethylformamide, etc.), and sulfoxides (such as dimethyl sulfoxide, etc.).

[0032] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is characterized in that: molecular sieves can be added in an amount of 0.1-1% by weight of the total raw materials, preferably 0.1-0.5%, and most preferably 0.1-0.3%.

[0033] Furthermore, the present invention provides a method for preparing a tocopherol derivative, which is also characterized in that the above-mentioned catalyst and co-catalyst are used to catalyze an esterification reaction.

[0034] The present invention also proposes the use of the tocopherol derivatives as antioxidants. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 .Hydrogen spectrum of the tocopherol derivative provided in Example 1.

[0036] Figure 2 . Reference curve of ascorbic acid (VC) scavenging effect on DPPH free radicals.

[0037] Figure 3 .The scavenging effect of the test substance on DPPH free radicals.

[0038] Figure 4 .The scavenging effect of the test product on ·OH. DETAILED DESCRIPTION

[0039] Theanine, tocopherol, sodium phosphate, a catalyst and a co-catalyst were mixed, stirred and reacted at room temperature for 4 hours, and the product was purified by post-treatment.

[0040] The product structure is:

[0041] R'=H; based on the demand for derivative products, the product can also be reacted with an acetylating agent (such as acetyl chloride) to produce a product in which R' is an acetyl group.

[0042] The catalyst is

[0043] R and R1 are the same or different alkyl or aryl groups, such as: straight-chain or branched alkyl groups with no more than 10 carbon atoms, such as: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, 2-methyl-butyl, etc.; aryl groups such as: phenyl, benzyl, p-tolyl, o-tolyl, m-tolyl, xylyl, p-methoxyphenyl, p-chlorophenyl, m-methoxyphenyl, m-chlorophenyl, o-methoxyphenyl, o-chlorophenyl, etc.

[0044] The catalyst is preferably selected from cat.1, cat.2 and cat.3,

[0045]

[0046] The co-catalyst is sodium phosphate;

[0047] The reaction solvent is selected from one or more of halogenated alkanes (such as dichloromethane, chloroform, etc.), ethers (such as tetrahydrofuran, dioxane, tert-butyl methyl ether, diethyl ether, etc.), nitriles (such as acetonitrile, etc.), amides (such as N,N-dimethylformamide, etc.), and sulfoxides (such as dimethyl sulfoxide, etc.).

[0048] The molar amount of the catalyst added is in the range of 0.2-0.5% of the total molar amount of the reactants, or selected from 2-10% of the total weight.

[0049] The molar ratio of theanine to tocopherol is selected within the range of 1-1.5:1.

[0050] The molar ratio of sodium phosphate to theanine is selected within the range of 0.1-0.5:1.

[0051] Molecular sieves may also be added in an amount of 0.1-1% by weight of the total raw materials.

[0052] The sources of raw materials used in this embodiment are as follows:

[0053] Product Name factory Specification Remark Theanine Shandong Pingju Biotechnology Co., Ltd. 1kg99% Configuration: L-theanine Tocopherol Maclean 1kg97% Configuration: DL-α-tocopherol Catalyst cat.1 Aladdin 1g99％ CAS: 141556-39-0 Catalyst cat.2 Aladdin 1g99％ CAS:1020098-95-6 Catalyst cat.3 Aladdin 1g99％ CAS: 3052255-14-5 Catalyst cat.4 Aladdin 1g99％ CAS: 54016-70-5 Catalyst cat.5 Aladdin 1g99％ CAS: 2107416-41-9 sodium phosphate Shanghai Haohong Biopharmaceutical Technology Co., Ltd. 1kg98% Tetrahydrofuran Shanghai Haohong Biopharmaceutical Technology Co., Ltd. AR Sodium bicarbonate Shanghai Haohong Biopharmaceutical Technology Co., Ltd. 1kg98% Sodium chloride Shanghai Haohong Biopharmaceutical Technology Co., Ltd. 1kg98%

[0054] The following are preferred embodiments:

[0055] Example 1. Preparation of tocopherol theanine ester catalyzed by cat.1

[0056] Theanine (5 g), tocopherol (3.9 g), cat. 1 (0.373 g), sodium phosphate (0.53 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to obtain 5.9 g of pure tocopherol theanine ester (97.6% purity), with a yield of 88%. 1 HNMR(400MHz,Chloroform-d)δ6.77(t,J=4.1Hz,1H),3.92–3.81(m,1H),3.41(dd,J=7.3, 6.6Hz,1H),3.26–3.16(m,2H),2.78(dd,J=7.8,5.0Hz,1H),2.72(dd,J=7.8,5.0Hz,1H),2 .38–2.25(m,2H),2.19–2.04(m,7H),2.04–1.90(m,1H),1.75(dd,J=7.8,5.0Hz,1H),1.73 –1.19(m,25H),1.13(t,J=6.4Hz,3H),0.85(dd,J=6.8,4.3Hz,9H),0.79(d,J=6.7Hz,3H).

[0057] LC-MS: 587.75 [M+H] +

[0058] Example 2: Preparation of tocopherol theanine ester catalyzed by cat.2

[0059] Theanine (5 g), tocopherol (3.9 g), cat.2 (0.363 g), sodium phosphate (0.53 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to obtain 5.2 g of pure tocopherol theanine ester (94.3% purity), with a yield of 75%.

[0060] Example 3: Preparation of tocopherol theanine ester catalyzed by cat.3

[0061] Theanine (5 g), tocopherol (3.9 g), cat.3 (0.353 g), sodium phosphate (0.53 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to obtain 6.2 g of pure tocopherol theanine ester (99.1% purity), with a yield of 92%.

[0062] Example 4: Preparation of tocopherol theanine ester catalyzed by cat.3

[0063] Theanine (5 g), tocopherol (3.9 g), cat.3 (0.353 g), sodium phosphate (0.53 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of a saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated and dried to yield 6.4 g of pure tocopherol theanine ester (99.3% purity), with a yield of 94%.

[0064] Example 5: Preparation of tocopherol theanine ester catalyzed by cat.3 (optimum conditions)

[0065] Theanine (5 g), tocopherol (3.9 g), cat.3 (0.353 g), sodium phosphate (0.53 g), molecular sieves (0.2 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of a saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated and dried with 40 ml of a saturated sodium chloride solution to obtain 6.9 g of pure tocopherol theanine ester (99.7% purity) with a yield of 98%.

[0066] Comparative Example 1.

[0067] Theanine (5 g), tocopherol (3.9 g), and tetrahydrofuran (100 mL) were added to a 250 mL three-necked flask and stirred at room temperature for 4 hours. The solid impurities were filtered out, and 40 mL of saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated. Chromatographic analysis showed almost no product.

[0068] Comparative Example 2.

[0069] Theanine (5 g), tocopherol (3.9 g), cat.3 (0.35 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered off and chromatographic analysis showed that there was almost no product.

[0070] Comparative Example 3.

[0071] In a 250ml three-necked flask, theanine (5g), tocopherol (3.9g), cat.4 (0.35 g) and tetrahydrofuran (100 mL) were mixed and stirred at room temperature for 4 hours. Solid impurities were filtered off, and 40 mL of saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated and chromatographic analysis showed that there was almost no product.

[0072] Comparative Example 4.

[0073] In a 250ml three-necked flask, theanine (5g), tocopherol (3.9g), cat.5 (0.35 g) and tetrahydrofuran (100 mL) were mixed and stirred at room temperature for 4 hours. Solid impurities were filtered off, and 40 mL of saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated and chromatographic analysis showed that there was almost no product.

[0074] Comparative Example 5.

[0075] Theanine (5 g), tocopherol (3.9 g), boric acid (0.3 g), oxalic acid (0.3 g), and tetrahydrofuran (100 mL) were added to a 250 mL three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 mL of saturated sodium bicarbonate solution was added. After stirring for 3 minutes, the organic phase was separated. Chromatographic analysis revealed almost no product.

[0076] Experimental Example 6.

[0077] Theanine (5 g), tocopherol (3.9 g), sodium phosphate (0.1 g), cat.3 (0.35 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to yield 4.1 g of pure tocopherol theanine ester (98.4% purity).

[0078] Experimental Example 7.

[0079] Theanine (5 g), tocopherol (3.9 g), sodium phosphate (0.9 g), cat.3 (0.35 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to yield 4.3 g of pure tocopherol theanine ester (98.1% purity).

[0080] Experimental Example 8.

[0081] Theanine (5 g), tocopherol (3.9 g), sodium phosphate (0.5 g), cat. 3 (0.35 g), and ethanol (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to yield 2.8 g of pure tocopherol theanine ester (91.1% purity).

[0082] Experimental Example 9.

[0083] Theanine (5 g), tocopherol (3.9 g), PBS (0.5 g), cat.3 (0.35 g), and tetrahydrofuran (100 mL) were added to a 250 ml three-necked flask and stirred at room temperature for 4 hours. Solid impurities were filtered out, and 40 ml of water was added. After stirring for 3 minutes, the organic phase was separated and dried to yield 3.3 g of pure tocopherol theanine ester (89.6% purity).

[0084] Experimental Example 10. Antioxidant Effect Test of Tocopherol Theanine Ester (wherein the test product is the pure tocopherol theanine ester synthesized in Example 1)

[0085] 1. DPPH free radical scavenging ability test

[0086] 1.1 Experimental Principle

[0087] The DPPH scavenging activity assessment method is an in vitro method for simulating antioxidant activity. DPPH is a stable, macromolecular free radical in organic solvents. It appears purple in methanol or ethanol, with maximum absorption at a wavelength of 517 nm. The DPPH colorimetric assay is based on the principle that a free radical scavenger can donate an electron to pair with the lone pair of electrons in DPPH. At a wavelength of 517 nm, the purple color of the scavenger changes to yellow. The change in absorbance is linearly related to the degree of free radical scavenging: the stronger the free radical scavenging ability, the lower the absorbance.

[0088] 1.2 Experimental Reagents

[0089] DPPH (Sigma), PBS (Gibco), anhydrous ethanol (Sinopharm), petroleum ether (Sinopharm), vitamin C (CNW), anhydrous ethanol (Sinopharm). Main equipment: microplate reader (Tecan, Spark), microvibrator (Qilin Bell, TS-92).

[0090] 1.3 Test methods

[0091] 1.3.1 Drawing the reference curve of DPPH free radical scavenging

[0092] Ascorbic acid (VC) was used as the system reference substance and diluted with PBS to five gradient concentrations of 12.5, 25, 50, 100, and 200 μg / mL. The test and calculation were performed according to the experimental method in 1.3.2. A reference curve was drawn with the reference substance concentration as the x-axis and the DPPH free radical scavenging rate as the y-axis.

[0093] 1.3.2 In vitro DPPH free radical scavenging assay

[0094] Prepare the test solution of the corresponding concentration, add the reagents in the amount shown in Table 1 below to prepare the reaction system, mix well, and set up 5 replicate wells for each concentration and 1 background control well.

[0095] Table 1 DPPH free radical scavenging test reaction system

[0096] Unit (μL) C1 C2 T1 T2 DPPH ethanol solution 180 0 180 0 Test liquid 0 0 20 20 Anhydrous ethanol 0 180 0 180 PBS 20 20 0 0

[0097] The reaction system was placed at room temperature in the dark for 30 minutes. After the reaction was completed, the absorbance OD value was read at 517 nm and the scavenging rate of the test sample on DPPH free radicals was calculated according to the following formula.

[0098] The scavenging rate of the test product on DPPH free radicals = [(C1-C2)-(T1-T2)] / (C1-C2)×100% Where: C1——absorbance value of blank system with DPPH

[0099] C2——Blank absorbance value of the DPPH-free system

[0100] T1——The test group has DPPH system absorbance value

[0101] T2——Absorbance value of the test group without DPPH system

[0102] 1.4 Results of in vitro DPPH free radical scavenging test

[0103] 1.4.1 The reference curve of DPPH free radical scavenging of the system reference substance is shown in Table 2 and Figure 2

[0104] Table 2 Analysis of system reference results

[0105]

[0106] 1.4.2 The results of the in vitro DPPH free radical scavenging test of the test products are shown in Tables 3 and Figure 3

[0107] Table 3 Analysis of DPPH free radical scavenging test results of the tested products

[0108]

[0109] Note: The number of * represents the level of significance, *** indicates high significance, and * indicates low significance.

[0110] 1.5. Conclusion

[0111] The test product can improve the scavenging rate of DPPH free radicals at a concentration of 0.02%-4%, which is statistically different from the control group (p<0.001), and has antioxidant capacity.

[0112] 2. OH ​​free radical scavenging ability test:

[0113] 2.1 Experimental Principle

[0114] When the body's antioxidant function weakens or cells in the body are damaged, excessive free radicals will be generated. Among various reactive oxygen free radicals, hydroxyl radicals (·OH) have the strongest reaction activity (107-1010M-1S-1) and are the most harmful to the body. Hydroxyl radicals are generated by the Fenton reaction: H202+Fe 2+ = OH + H20 + Fe 3+ The generated ·OH reacts with salicylic acid to form a product with a specific absorption at 520nm. Adding a test substance with ·OH scavenging ability to the reaction system reduces the generated ·OH, thereby reducing the amount of colored compounds. The degree of absorbance change is related to the degree of ·OH scavenging: the stronger the ·OH scavenger, the lower the absorbance.

[0115] 2.2 Test methods

[0116] Prepare the test sample into a test solution of the appropriate concentration. Add various reagents according to the test method in Table 4 below. Measure the absorbance at 520 nm and calculate the clearance rate of the test sample using the following formula. Set the test sample to a five-point concentration gradient, and repeat the test five times for each concentration.

[0117] OH scavenging rate of the test product = [(AC)-(BD)] / (AC)×100%

[0118] Table 4 OH scavenging capacity reaction system

[0119] A (control group) B (test group) C (control reference) D (reference of the product to be tested) 0.2 mL distilled water 0.2mL test solution 0.2 mL distilled water 0.2mL test solution <![CDATA[0.2mLFeSO4]]> <![CDATA[0.2mLFeSO4]]> <![CDATA[0.2mLFeSO4]]> <![CDATA[0.2mLFeSO4]]> <![CDATA[0.4mLH2O2]]> <![CDATA[0.4mLH2O2]]> <![CDATA[0.4mLH2O2]]> <![CDATA[0.4mLH2O2]]> Reaction 10 minutes Reaction 10 minutes Reaction 10 minutes Reaction 10 minutes 0.2 mL salicylic acid ethanol solution 0.2 mL salicylic acid ethanol solution 0.2 mL of anhydrous ethanol solution 0.2 mL of anhydrous ethanol solution

[0120] 2.3. In vitro OH scavenging test results of the test product

[0121] Table 5 Analysis of test results of OH removal test of tested products

[0122]

[0123] Note: The number of * represents the level of significance, *** indicates high significance, and * indicates low significance.

[0124] 2.4. Experimental Conclusions

[0125] The test product can improve the clearance rate of ·OH at a concentration of 0.02%-4%, which is statistically different from the control group (p<0.001), and has antioxidant capacity.

Claims

1. A tocopherol derivative, characterized in that The compound shown in the following structure: R' is hydrogen or acetyl.

2. A method for preparing the tocopherol derivative according to claim 1, characterized in that: Under the action of a catalyst and a catalytic aid, theanine and tocopherol are esterified to obtain a tocopherol derivative; The catalyst is selected from the compounds shown in the following structure: R and R1 are the same or different alkyl or aryl groups; The alkyl group is selected from a straight chain or branched chain alkyl group having no more than 10 carbon atoms, and the aryl group is selected from a phenyl group, a benzyl group, a p-tolyl group, an o-tolyl group, an m-tolyl group, a xylyl group, a p-methoxyphenyl group, a p-chlorophenyl group, a m-methoxyphenyl group, a m-chlorophenyl group, an o-methoxyphenyl group, and an o-chlorophenyl group.

3. The preparation method according to claim 2, wherein: The molar amount of the catalyst added is 0.2-0.5% of the total molar amount of the reactants.

4. The preparation method according to claim 2, wherein: The molar ratio of theanine to tocopherol is 1-1.5:

1.

5. The preparation method according to claim 2, wherein: The catalyst auxiliary agent is sodium phosphate.

6. The preparation method according to claim 2, wherein: The molar ratio of the catalyst aid to theanine is 0.1-0.5:

1.

7. The preparation method according to claim 2, wherein: Theanine, tocopherol, a catalytic aid and a catalyst are mixed, stirred and reacted at room temperature for 4-6 hours, and the product is purified by post-treatment.

8. The preparation method according to claim 7, wherein: Molecular sieves were also added.

9. Use of the tocopherol derivative according to claim 1 and the tocopherol derivative prepared by the preparation method according to any one of claims 2 to 8 as an antioxidant.

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