Method for preparing trilobatin by taking hesperidin as raw material

Abstract

The invention relates to a method for preparing trilobatin by taking hesperidin as a raw material, which comprises the following steps of: 1, hydrolyzing the hesperidin with the content of more than 90 percent as the raw material to remove rhamnose to obtain an intermediate 1; step 2, reacting the obtained intermediate 1 with p-hydroxybenzaldehyde to obtain an intermediate 2; 3, the obtained intermediate 2 is subjected to a reduction reaction and then purified, and the product trilobatin is obtained. The hesperidin is used as the main raw material to prepare the trilobatin, the hesperidin serving as the raw material is sufficient in source and low in cost and meets market requirements and has competitive advantages, and the preparation method is easy to operate and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to a method for preparing tilobatin, and more particularly to a method for preparing tilobatin using hesperidin as a raw material. Background Art

[0002] Tilobatin, with the English name Tilobatin, has the following structural formula:

[0003]

[0004] Tilobatin is a natural dihydrochalcone compound and a newly emerging functional sweetener in recent years, which has a wide range of applications in the food field. It is non-hygroscopic, non-deliquescent, has a sweetness 300 times that of sucrose, good stability, can replace sucrose, and the products prepared with tilobatin have a unique flavor. Moreover, tilobatin has functions such as hypoglycemic, antioxidant, anti-inflammatory, and anti-tumor effects, and has a good sweet taste. It is expected to become another natural high-potency sweetener after steviol glycosides and mogroside. Currently, the main sources of tilobatin are plant extraction and chemical synthesis.

[0005] Chinese Patent CN202011299891.7 discloses a method for extracting tilobatin from Lithocarpus litseifolius. The leaves of Lithocarpus litseifolius are extracted with ethanol or methanol, concentrated, suspended in water, and extracted with petroleum ether and ethyl acetate respectively. The ethyl acetate extraction part is further separated and recrystallized by silica gel column chromatography, alumina column chromatography, and polyamide column chromatography repeatedly to obtain high-purity tilobatin. However, extracting tilobatin from the leaves of Lithocarpus litseifolius has a high cost due to resource and extraction rate limitations, which is not conducive to market promotion.

[0006] Chinese Patent CN202211555170.7 discloses a method for synthesizing tilobatin from naringin. Naringin is dissolved in sodium hydroxide solution for hydrogenation to obtain naringin dihydrochalcone; naringin dihydrochalcone reacts with rhamnosidase solution; the pH of the solution is adjusted to obtain tilobatin. When using naringin as a raw material to prepare tilobatin, it is necessary to have sufficient naringin as a raw material. Naringin is derived from the young fruits of the citrus plant pomelo. Currently, the output of this kind of pomelo fruit in China is limited. At the same time, naringin, as a starting material for semi-synthesis of various health care products or flavonoid products, has long been in short supply and its price has increased sharply year by year. Therefore, the preparation of tilobatin from naringin is easily restricted by the raw material source and cost price. In summary, inventing a new method for preparing tilobatin with low cost and sufficient raw material sources is a problem that needs to be solved currently. Summary of the Invention

[0007] The object of the present invention is to solve the technical problems of limited raw material sources, extraction rate, and high cost price in the preparation of tilobatin in the prior art, and to provide a method for preparing tilobatin using hesperidin as the main raw material, which has sufficient raw materials, simple operation, and is suitable for industrial production.

[0008] The inventive concept of the present invention is as follows:

[0009] Using hesperidin with a content greater than 90% as the main raw material, first hydrolyze to remove rhamnose to obtain intermediate 1, then react with p-hydroxybenzaldehyde under alkaline conditions to obtain intermediate 2, and finally carry out a reduction reaction and purification treatment to obtain the product naringin. The reaction process is as follows:

[0010]

[0011] To achieve the above-mentioned invention purpose and complete the above-mentioned inventive concept, the technical solution adopted by the present invention is as follows:

[0012] A method for preparing naringin from hesperidin as a raw material, which is characterized in that it includes the following steps:

[0013] Step 1: Using hesperidin with a content greater than 90% as a raw material, hydrolyze to remove rhamnose to obtain intermediate 1;

[0014] Step 2: React the obtained intermediate 1 with p-hydroxybenzaldehyde to obtain intermediate 2;

[0015] Step 3: Carry out a reduction reaction on the obtained intermediate 2, and then carry out purification treatment to obtain the product naringin.

[0016] Further, step 1 is specifically as follows:

[0017] Step 1.1: Mix hesperidin with a content greater than 90%, methanol and crude enzyme extract of Aspergillus niger, stir evenly, adjust the pH value to 5.5 - 6.5, raise the temperature to 40°C - 60°C for reaction, and hydrolyze to remove rhamnose;

[0018] Step 1.2: After the reaction is completed, remove the solvent and recover methanol, add water, raise the temperature to reflux and stir evenly, filter to obtain a solid, and the solid is washed with water and dried to obtain intermediate 1;

[0019] Step 2 is specifically as follows:

[0020] Step 2.1: Mix intermediate 1, dimethyl sulfoxide, 90% methanol and p-hydroxybenzaldehyde, raise the temperature to 40°C - 50°C, add potassium hydroxide in batches, and continue to raise the temperature to 60°C - 80°C for reaction;

[0021] Step 2.2: After the reaction is completed, cool to room temperature, add glacial acetic acid for heat preservation and add water to stir, then add chloroform and stir evenly, filter to obtain a pale yellow solid, and the pale yellow solid is continuously rinsed with chloroform, washed with water until neutral and dried to obtain intermediate 2.

[0022] Further, in Step 1.1, the mass ratio of hesperidin to methanol is 1:5 to 1:8; the mass ratio of the crude enzyme extract of Aspergillus niger to hesperidin is 0.03:1.

[0023] Further, Step 3 is specifically as follows: Add intermediate 2, 5% sodium hydroxide solution, and palladium carbon into a high-pressure reaction kettle. After hydrogenation reduction reaction, perform purification treatment to obtain trilobatin.

[0024] Further, Step 3 specifically includes the following steps:

[0025] Step 3.1: Add the obtained intermediate 2, 5% sodium hydroxide solution, and palladium carbon into a high-pressure reaction kettle. Pass hydrogen and keep warm at a pressure of 0.5 MPa for 2 - 4 h. When the liquid phase detects that the content of intermediate 2 is less than 0.5%, stop hydrogenation.

[0026] Step 3.2: Adjust the pH to 4 with hydrochloric acid, continue to cool down to 0°C - 5°C and keep warm for 8 h. After filtration, dissolve with 50% ethanol by heating, decolorize with activated carbon, cool down to 0°C and keep warm for 4 h, then filter, and then heat up to 60°C for drying to obtain trilobatin.

[0027] Further, in Step 1.1, use sodium hydrogen phosphate - citric acid buffer solution to adjust the pH value; in Step 1.2, the amount of water added for heating under reflux is 3 - 5 times the mass of hesperidin.

[0028] Further, in Step 2.1, the mass ratio of intermediate 1 to dimethyl sulfoxide is 1:3 to 1:5; the mass ratio of intermediate 1 to 90% methanol is 1:1 to 1:3; the molar ratio of p-hydroxybenzaldehyde to intermediate 1 is 1:1.5 to 1:3; the mass ratio of intermediate 1 to potassium hydroxide is 2:1 to 5:1;

[0029] In Step 2.2, the molar ratio of glacial acetic acid to potassium hydroxide is 1.2 - 1.5:1.

[0030] Further, in Step 3.1, the mass ratio of intermediate 2 to 5% sodium hydroxide solution is 1:4 to 1:7; the mass ratio of palladium carbon to intermediate 2 is 1:3.3.

[0031] Further, in Step 1.2, when the liquid phase detects that the content of hesperidin is less than 0.5%, it is regarded as the end of the reaction;

[0032] In Step 2.2, when the in - process control detects that the content of intermediate 1 is less than 0.5%, it is regarded as the end of the reaction;

[0033] In Step 3.1, when the liquid phase detects that the content of intermediate 2 is less than 0.5%, it is regarded as the end of the reaction.

[0034] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0035] 1. The present invention provides a method for preparing naringin from hesperidin as a raw material. First, under the action of an enzyme, hesperidin is hydrolyzed to remove rhamnose to obtain intermediate 1. The hydrolyzed hesperidin raw material can be less than 0.5%, and the purity of the product intermediate 1 is greater than 98%. Since solid potassium hydroxide dissolves in dimethyl sulfoxide and shows strong alkalinity, and intermediate 1 can be completely dissolved in a low amount of dimethyl sulfoxide solvent at a relatively low temperature, the present invention utilizes this property and uses a mixture of dimethyl sulfoxide and methanol as the reaction solvent to react intermediate 1 with p-hydroxybenzaldehyde. Without using too high a temperature, a low amount of powdered potassium hydroxide is used as the alkaline catalyst to prepare intermediate 2. From the liquid phase control, this reaction has almost no side reactions and a high conversion rate, and the obtained product has a purity greater than 98%.

[0036] 2. By setting hydrolysis first and then ring-opening substitution, the present invention achieves the technical effect that the purities of both reaction intermediates 1 and 2 are above 98%, providing high-quality and stable intermediate raw materials for the last step of hydrogenation reduction reaction.

[0037] 3. The present invention uses hesperidin as the main raw material to prepare naringin. The raw material hesperidin has sufficient supply and low price, has a competitive advantage in meeting market demand, and the preparation method is simple to operate and suitable for industrial production. At the same time, it also solves the problem of a large backlog of hesperidin inventory on the market due to the sluggish market of hesperidin and its derivative series products in recent years. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the liquid chromatogram of hesperidin in Example 1 of the method for preparing naringin from hesperidin as a raw material according to the present invention;

[0039] Figure 2 is the liquid chromatogram of intermediate 1 in Example 1 of the method for preparing naringin from hesperidin as a raw material according to the present invention;

[0040] Figure 3 is the liquid chromatogram of intermediate 2 in Example 1 of the method for preparing naringin from hesperidin as a raw material according to the present invention;

[0041] Figure 4 is the liquid chromatogram of naringin in Example 1 of the method for preparing naringin from hesperidin as a raw material according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] Example 1

[0043] Step 1: In a 500 ml reaction flask, add 50 g of hesperidin (content greater than 90%), 250 g of methanol, and 1.5 g of crude enzyme extract of Aspergillus niger. After stirring evenly, adjust the pH of the reaction solution to 5.6 with disodium hydrogen phosphate - citric acid buffer. Heat the water bath to 50 °C and keep the reaction at this temperature for 6 h. After 6 h, the liquid phase detection shows that the content of hesperidin is less than 0.5%. As shown in Figure 1 Stop the reaction, recover methanol to dryness, add 150 g of water, continue to heat and reflux for 2 h, filter, wash the filter cake with methanol, and dry to obtain 32.6 g of intermediate 1 with a purity greater than 98%. As shown in Figure 2

[0044] Step 2: In a 500 ml reaction flask, add 30 g of intermediate 1, 90 g of dimethyl sulfoxide, 30 g of 90% methanol, and 12.3 g of p-hydroxybenzaldehyde. Heat to 40 °C until the system dissolves and becomes clear, and then add 6 g of powdered potassium hydroxide in batches. After adding, heat to 70 °C and keep the reaction at this temperature for 3 h. After 3 h, the in-process control detection shows that the content of intermediate 1 is less than 0.5%. Cool to room temperature, add 7.8 g of glacial acetic acid, and keep the temperature for 1 h. Stop the reaction, add 100 g of water, stir evenly, adjust the pH to 4 with 5% hydrochloric acid, add 100 g of chloroform, stir for 1 h, filter, wash with chloroform, then wash with water until neutral, and dry to obtain a light yellow solid, which is intermediate 2, 22.3 g, with a liquid phase purity greater than 98%. As shown in Figure 3

[0045] Step 3: In a 1000 ml high-pressure reaction kettle, add 30 g of intermediate 2, 150 g of 5% sodium hydroxide solution, and 9 g of palladium-carbon (containing 10% palladium). Pass hydrogen under a pressure of 0.5 MPa and keep the reaction at this temperature for 2 h. The liquid phase detection shows that the content of intermediate 2 is less than 0.5%, then stop hydrogenation. Adjust the pH of the reaction solution to 4 with hydrochloric acid, cool to 0 °C - 5 °C and keep the temperature for 8 h, filter, dissolve the solid in 120 g of 50% ethanol by heating, decolorize with activated carbon, cool to 0 °C and keep the temperature for 4 h, then filter, and dry at 60 °C to obtain 26.8 g of trilobatin with a liquid phase content of 98.3%. As shown in Figure 4

[0046] Example 2

[0047] Step 1: In a 500 ml reaction flask, add 50 g of hesperidin (content greater than 90%), 300 g of methanol, and 1.5 g of crude enzyme extract of Aspergillus niger. After stirring evenly, adjust the pH of the reaction solution to 6 with disodium hydrogen phosphate - citric acid buffer. Heat the water bath to 60 °C and keep the reaction at this temperature for 4.5 h. After 4.5 h, the liquid phase detection shows that the content of hesperidin is less than 0.5%. Stop the reaction, recover methanol to dryness, add 250 g of water, continue to heat and reflux for 2 h, filter, wash the filter cake with methanol, and dry to obtain 29.3 g of intermediate 1 with a purity greater than 98%.

[0048] ​​​Step 2: In a 500 ml reaction flask, add 30 g of Intermediate 1, 150 g of dimethyl sulfoxide, 90 g of 90% methanol, and 13.2 g of p-hydroxybenzaldehyde. Heat the mixture to 50 °C until the system dissolves and becomes clear. Then, add 12 g of powdered potassium hydroxide in batches. After addition, heat the mixture to 80 °C and keep it for reaction. After 1.5 h, conduct in-process inspection. The content of Intermediate 1 is less than 0.5%. Cool the mixture to room temperature, add 16.7 g of glacial acetic acid, and keep it for 1 h. Stop the reaction, add 200 g of water, stir well, adjust the pH to 5 with 5% hydrochloric acid, add 150 g of chloroform, stir for 1 h, filter, wash with chloroform, then wash with water until neutral, and dry to obtain 20.7 g of a pale yellow solid, which is Intermediate 2 with a liquid phase purity greater than 98%.

[0049] Step 3: In a 1000 ml high-pressure reactor, add 30 g of Intermediate 2, 210 g of 3% sodium hydroxide solution, and 9 g of palladium-carbon (containing 10% palladium). Pass hydrogen under a pressure of 0.5 MPa and keep it for reaction for 2 h. Conduct liquid phase detection. When the raw materials disappear, stop hydrogenation. Adjust the pH of the reaction solution to 4 with hydrochloric acid, cool it to 0 °C - 5 °C and keep it for 8 h, filter, dissolve the solid in 120 g of 50% ethanol by heating, decolorize with activated carbon, then cool it to 0 °C and keep it for 4 h, filter, and dry at 60 °C to obtain 27.8 g of trilobatin with a liquid phase content of 98.6%.

[0050] Example 3

[0051] Step 1: In a 2000 ml reaction flask, add 75 g of hesperidin (content greater than 90%), 600 g of methanol, and 2.3 g of crude enzyme extract of Aspergillus niger. Stir well and adjust the pH of the reaction solution to 6.0 with sodium hydrogen phosphate-citric acid buffer solution. Heat it in a water bath to 50 °C and keep it for reaction. After 5 h, conduct liquid phase detection. The content of hesperidin is less than 0.5%. Stop the reaction, recover methanol to dryness, add 375 g of water, continue to heat and reflux for 2 h, filter, wash the filter cake with methanol, and dry to obtain 41.3 g of Intermediate 1 with a purity greater than 98%.

[0052] Step 2: In a 2000 ml reaction flask, add 50 g of Intermediate 1, 250 g of dimethyl sulfoxide, 120 g of 90% methanol, and 20.5 g of p-hydroxybenzaldehyde. Heat the mixture to 40 °C until the system dissolves and becomes clear. Then, add 25 g of powdered potassium hydroxide in batches. After addition, heat the mixture to 70 °C and keep it for reaction. After 5 h, conduct in-process inspection. The content of Intermediate 1 is less than 0.5%. Cool the mixture to room temperature, add 40 g of glacial acetic acid, keep it for 1 h and stop the reaction, add 250 g of water, stir well, adjust the pH to 4 with 5% hydrochloric acid, add 150 g of chloroform, stir for 1 h, filter, wash with chloroform, then wash with water until neutral, and dry to obtain 38.6 g of a pale yellow solid, which is Intermediate 2 with a liquid phase purity greater than 98%.

[0053] Step 3: In a 1000 ml high-pressure reactor, add 50 g of Intermediate 2, 250 g of 3% sodium hydroxide solution, and 15 g of palladium on carbon (containing 10% palladium). Pass hydrogen under a pressure of 0.5 MPa and maintain the reaction at a constant temperature for 2 h. Detect by liquid phase that the raw materials have disappeared, and stop hydrogenation. Adjust the pH of the reaction solution to 4 with hydrochloric acid, cool down to 0°C - 5°C and keep warm for 8 h, then filter. The solid is dissolved by heating with 200 times the amount of 50% ethanol, decolorized with activated carbon, cooled down to 0°C and kept warm for 4 h, then filtered and dried at 60°C to obtain 47.2 g of trilobatin with a liquid phase content of 98.9%.

[0054] Example 4

[0055] Step 1: In a 2000 ml reaction flask, add 75 g of hesperidin (content greater than 90%), 480 g of methanol, and 2.3 g of crude enzyme extract of Aspergillus niger. After stirring evenly, adjust the pH of the reaction solution to 5.5 with sodium hydrogen phosphate-citric acid buffer solution. Heat up to 60°C in a water bath and maintain the reaction at a constant temperature. After 8 h, detect by liquid phase that the hesperidin is less than 0.5%. Stop the reaction, recover methanol to dryness, add 300 g of water, continue to heat up and reflux for 2 h, then filter. The filter cake is rinsed with methanol and dried to obtain 42.6 g of Intermediate 1 with a purity greater than 98%.

[0056] Step 2: In a 2000 ml reaction flask, add 50 g of Intermediate 1, 200 g of dimethyl sulfoxide, 80 g of 90% methanol, and 20.5 g of p-hydroxybenzaldehyde. Heat up to 40°C, and the system becomes clear after dissolution. Add 20 g of powdered potassium hydroxide in batches. After adding, heat up to 80°C and maintain the reaction at a constant temperature. After 3 h, detect by in-process control that Intermediate 1 is less than 0.5%. Cool down to room temperature, add 32 g of glacial acetic acid, and keep warm for 1 h. Stop the reaction, add 250 g of water, stir evenly, adjust the pH to 4 with 5% hydrochloric acid, add 250 g of chloroform, stir for 1 h, then filter, rinse with chloroform, and then wash with water until neutral, and dry to obtain a pale yellow solid, which is Intermediate 2, 35.5 g, with a liquid phase purity greater than 98%.

[0057] Step 3: In a 1000 ml high-pressure reactor, add 50 g of Intermediate 2, 200 g of 3% sodium hydroxide solution, and 15 g of palladium on carbon (containing 10% palladium). Pass hydrogen under a pressure of 0.5 MPa and maintain the reaction at a constant temperature for 4 h. Detect by liquid phase that the raw materials have disappeared, and stop hydrogenation. Adjust the pH of the reaction solution to 4 with hydrochloric acid, cool down to 0°C - 5°C and keep warm for 8 h, then filter. The solid is dissolved by heating with 180 times the amount of 50% ethanol, decolorized with activated carbon, cooled down to 0°C and kept warm for 4 h, then filtered and dried at 60°C to obtain 46.3 g of trilobatin with a liquid phase content of 98.1%.

[0058] In the above examples, the in-process control conditions for liquid phase detection are as follows:

[0059]

[0060] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for preparing trilobatin using hesperidin as raw material, characterized in that: The following steps are involved: Step 1, using hesperidin with a content greater than 90% as a raw material, hydrolyzing and removing rhamnose to obtain intermediate 1; Step 2, reacting the obtained intermediate 1 with p-hydroxybenzaldehyde to obtain intermediate 2; Step 3: subjecting the obtained intermediate 2 to a reduction reaction, followed by purification, to obtain the product trilobatin.

2. The method for preparing trilobatin using hesperidin as raw material according to claim 1, characterized in that: Step 1 is as follows: Step 1.1, mixing hesperidin with a content greater than 90%, methanol and crude enzyme extract of Aspergillus niger, stirring evenly, adjusting the pH value to 5.5-6.5, heating to 40° C.-60° C. for reaction, and hydrolyzing and removing rhamnose; Step 1.2, after the reaction is completed, the methanol is removed and recovered, water is added, the temperature is raised to reflux and stirred evenly, and a solid is obtained after filtration, and the solid is washed with water and dried to obtain an intermediate 1; Step 2 is as follows: Step 2.1, mix the intermediate 1, dimethyl sulfoxide, 90% methanol and p-hydroxybenzaldehyde, raise the temperature to 40°C to 50°C, add potassium hydroxide in batches, and continue to raise the temperature to 60°C to 80°C for reaction; Step 2.2, after the reaction is completed, cool to room temperature, add glacial acetic acid to keep warm and add water to stir, then add chloroform and stir evenly, filter to obtain a light yellow solid, rinse the light yellow solid with chloroform, wash with water until neutral, and dry to obtain intermediate 2.

3. The method for preparing trilobatin using hesperidin as raw material according to claim 2, characterized in that: In step 1.1, the mass ratio of hesperidin to methanol is 1:5-1:8; the mass ratio of Aspergillus niger crude enzyme extract to hesperidin is 0.03:

1.

4. The method for preparing trilobatin using hesperidin as raw material according to claim 1, characterized in that: Step 3 is specifically as follows: adding 2% and 5% sodium hydroxide solution and palladium carbon of the intermediate into a high-pressure reactor, performing a hydrogenation reduction reaction, and then purifying to obtain trilobatin.

5. The method for preparing trilobatin using hesperidin as raw material according to claim 4, characterized in that: Step 3 specifically includes the following steps: Step 3.1, add the obtained intermediate 2, 5% sodium hydroxide solution and palladium carbon into a high-pressure reactor, pass hydrogen at a pressure of 0.5 MPa for 2 to 4 hours, and stop hydrogenation when the intermediate 2 is less than 0.5% by liquid phase detection; Step 3.2, adjust the pH to 4 with hydrochloric acid, continue to cool to 0°C-5°C and keep warm for 8 hours, filter and dissolve with 50% ethanol, decolorize with activated carbon, cool to 0°C and keep warm for 4 hours, filter, and then heat to 60°C to dry to obtain trilobatin.

6. The method for preparing trilobatin using hesperidin as raw material according to claim 2, characterized in that: In step 1.1, the pH value is adjusted using disodium hydrogen phosphate-citric acid buffer; In step 1.2, the amount of water added for heating and reflux is 3 to 5 times the mass of hesperidin.

7. The method for preparing trilobatin using hesperidin as raw material according to claim 2, characterized in that: In step 2.1, the mass ratio of intermediate 1 to dimethyl sulfoxide is 1:3 to 1:5; the mass ratio of intermediate 1 to 90% methanol is 1:1 to 1:3; the molar ratio of p-hydroxybenzaldehyde to intermediate 1 is 1:1.5 to 1:3; the mass ratio of intermediate 1 to potassium hydroxide is 2:1 to 5:1; In step 2.2, the molar ratio of glacial acetic acid to potassium hydroxide is 1.2-1.5:

1.

8. The method for preparing trilobatin using hesperidin as raw material according to claim 5, characterized in that: In step 3.1, the mass ratio of intermediate 2 to 5% sodium hydroxide solution is 1:4 to 1:7; the mass ratio of palladium carbon to intermediate 2 is 1:3.

3.

9. The method for preparing trilobatin using hesperidin as raw material according to claim 5, characterized in that: In step 1.2, when the hesperidin content detected by liquid phase is less than 0.5%, the reaction is considered to be completed; In step 2.2, when the intermediate 1 detected by the central control is less than 0.5%, the reaction is considered to be completed; In step 3.1, when the content of intermediate 2 detected by liquid phase is less than 0.5%, the reaction is considered to be completed.

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