Preparation method of dipeptide-2

Abstract

The invention discloses a preparation method of dipeptide-2, and belongs to the technical field of organic synthesis. The preparation method comprises two core reactions, wherein an intermediate compound 3 is obtained through a condensation reaction, and then high-purity dipeptide-2 is obtained through hydrolysis, deprotection and recrystallization. The preparation method is simple to operate, the raw materials are easy to obtain, the prepared dipeptide-2 is high in purity and high in yield, the solvent can be recycled, and the preparation method conforms to the green chemistry concept and is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of organic synthetic chemistry technology, and specifically relates to a method for preparing dipeptide-2. Background Technology

[0002] Dipeptide-2 is a mixture of two amino acid molecules widely used in cosmetics and skincare products. It primarily functions to condition, moisturize, and provide antioxidant benefits. With a risk factor of 1, it is considered highly safe, and its use during pregnancy generally has no adverse effects. Furthermore, it is not carcinogenic. In terms of skincare efficacy, dipeptide-2 can effectively improve eye puffiness. As an angiotensin-converting enzyme (ACE) inhibitor, it improves local blood circulation by inhibiting the conversion of angiotensin I to angiotensin II, thereby reducing eye bags. Its drainage effect has been shown to be noticeable within 15 days. While reducing eye bags, it also tightens and smooths the skin, often adding it to lotions, gels, serums, and other cosmetic formulations to achieve the dual skincare goals of reducing eye bags and anti-wrinkle effects.

[0003] Regarding the preparation technology of dipeptide-2, existing synthetic methods are mainly divided into two categories: biosynthesis and chemical synthesis. Senoo et al. used a biosynthetic method, using the histagged protein of recombinant Actinobacillus pleuropneumoniae (APP) serotype 1 strain 407 as a ligase, and catalyzed the reaction with L-valine and L-tryptophanase for 16 hours in a buffer solution system at 37 °C and pH = 8 to obtain dipeptide-2. AMBobie, on the other hand, used a chemical synthesis route, first protecting valine with Cbz, then activating it with (pentafluorophenyl) carbonate and reacting it with sodium tryptophan to obtain Cbz-protected dipeptide-2, and then catalytically deprotecting it with hydrogen to obtain the target product dipeptide-2. The above-reported preparation methods have obvious defects, either due to high cost or harsh reaction conditions, making them difficult to adapt to the needs of large-scale industrial production. Furthermore, Chinese invention patent CN119708119A discloses a synthetic process for dipeptide-2. This process involves separating Boc-L-valine to prepare Boc-L-valine hydroxysuccinimide ester, followed by L-tryptophan hydrolysis, deprotection with trifluoroacetic acid, and recrystallization to obtain dipeptide-2. This process is cumbersome, and Boc-L-valine hydroxysuccinimide ester is highly reactive and easily hydrolyzed, making industrialization difficult. Summary of the Invention

[0004] To address the problems in existing technologies, this invention provides a method for preparing dipeptide-2, which yields high-purity dipeptide-2 with high yield, simple operation, and readily available raw materials.

[0005] The technical solution of the present invention is as follows:

[0006] This invention provides a method for preparing dipeptide-2, comprising the following steps:

[0007] Step (1): Dissolve compound 1 and compound 4 in solvent I, add base a, and react at 15-30℃ for 10-20 min. Then slowly add compound 2 and react at 15-30℃ for 10-20 min. After the reaction is complete, extract, dry and separate to obtain compound 3.

[0008] The reaction equation for step (1) is as follows:

[0009]

[0010] Step (2): Dissolve compound 3 in solvent II, add base b to react, and after the reaction is complete, extract and distill under reduced pressure to obtain crude product 5; add acid to crude product 5 to react, and after the reaction is complete, distill under reduced pressure, recrystallize and centrifuge to obtain compound 6, namely dipeptide-2;

[0011] The reaction equation for step (2) is as follows:

[0012]

[0013] Among them, R 1 Selected from C1~C10 alkoxycarbonyl, sulfonyl, and acyl groups;

[0014] R 2 Selected from C1~C10 alkyl, C3~C10 cycloalkyl, heterocycloalkyl, aryl, and heteroaryl;

[0015] R 3 Selected from nitro, nitrile, ester, halogen, alkylsulfonyl, and arylsulfonyl groups;

[0016] R 4 Selected from nitro, nitrile, ester, halogen, alkylsulfonyl, and arylsulfonyl groups;

[0017] R 5 Selected from C4~C10 alkoxycarbonyl, sulfonyl, and C4-C16 alkyl.

[0018] As a further preferred embodiment of the technical solution of the present invention.

[0019] Further, in step (1), compound 1 is N-tert-butoxycarbonyl-L-valine, compound 4 is tetrafluorophthalonitrile, base a is N,N-diisopropylethylamine, solvent I is N,N-dimethylformamide, and compound 2 is L-tryptophan methyl ester.

[0020] Further, in step (1), the molar ratio of compound 1, compound 4 and base a is 1:1-1.5:1-1.5; the molar ratio of compound 1 to compound 2 is 1:1-1.5.

[0021] Further, in step (2), the base b is NaOH, the solvent II is methanol, the acid is 4M HCl / 1,4-dioxane solution, and the recrystallization solvent is diethyl ether.

[0022] Furthermore, the reaction temperature in step (2) is 15-30℃; the reaction time of compound 3 with base b is 25-40 min, and the reaction time of crude product 5 with acid is 25-40 min.

[0023] Further, in step (2), the mass ratio of compound 3 to base b is 3-4:1; the mass ratio of compound 3 to acid is 1:15-18.

[0024] Furthermore, in step (1), the amount of solvent I added is 1-2 times the mass of compound 1; in step (2), the amount of solvent II added is 10-12 times the mass of compound 3.

[0025] Furthermore, the reaction process was monitored using thin-layer chromatography in both steps (1) and (2).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The preparation method of the present invention is simple to operate, the reaction conditions are mild, no harsh conditions such as high pressure and high temperature are required, and the reaction time is short, which greatly improves the production efficiency.

[0028] (2) The raw materials used in this invention are readily available and inexpensive, and are easy to obtain for industrialization, which effectively reduces production costs;

[0029] (3) The dipeptide-2 obtained by the present invention has high purity and high yield. The product yield in step (1) can reach 96% and the product yield in step (2) can reach 92%.

[0030] (4) The solvents used in the process of this invention can be recycled and reused after the extraction process, which not only effectively reduces the production cost, but also conforms to the development concept of green chemistry and has the potential for large-scale industrial production. Attached Figure Description

[0031] Figure 1 The image shows the HPLC chromatogram of dipeptide-2 prepared in Example 1. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to examples. The following content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

[0033] The preparation method of the present invention will be described below through specific embodiments.

[0034] Example 1

[0035] The specific experimental steps for preparing dipeptide-2 are as follows:

[0036] 217 mg (1 mmol) of N-tert-butoxycarbonyl-L-valine and 240 mg (1.2 mmol) of tetrafluorophthalonitrile were added to a 50 mL round-bottom flask. 2 mL of N,N-dimethylformamide was added to dissolve the valine, followed by the addition of 154.8 mg (1.2 mmol) of N,N-diisopropylethylamine. After the addition was complete, the mixture was reacted at room temperature for 10 minutes. Then, 305.6 mg (1.2 mmol) of L-tryptophan methyl ester was slowly added, and the mixture was reacted at room temperature for 20 minutes. After the reaction was complete, the product was extracted, concentrated, and purified by column chromatography to obtain the target product 3 (437.76 mg) (0.96 mmol), with a yield of 96%.

[0037]

[0038] 1 H NMR (300 MHz, DMSO-d6) δ 10.89 (s, 1H), 8.28 (d, J = 6.9 Hz, 1H), 7.50 (d, J = 7.7 Hz, 1H), 7.35 (d, J = 8.0 Hz, 1H), 7.18 (s, 1H), 7.08 (t, J= 7.4 Hz, 1H), 6.99 (t, J = 7.3 Hz, 1H), 6.63 (d, J = 9.2 Hz, 1H), 4.56 (d, J= 6.5 Hz, 1H), 3.87 (t, J = 7.7 Hz, 1H), 3.27 – 2.98 (m, 2H), 2.05 – 1.81 (m,1H), 1.39 (s, 9H), 0.82 (t, J = 4.0 Hz, 9H).

[0039] 13C NMR (75 MHz, DMSO-d6) δ 172.6, 172.0, 155.8, 136.5, 127.5, 124.1,121.4, 118.8, 118.4, 111.9, 109.7, 78.5, 65.5, 59.8, 53.4, 52.1, 31.1, 28.6,19.5, 18.5.

[0040] 181.7 mg (0.398 mmol) of compound 3 was dissolved in 2.0 mL of methanol, and 48 mg (1.2 mmol) of NaOH was added. The mixture was stirred at room temperature for 30 min, and the reaction was monitored by TLC. After the reaction was complete, 10 mL of dilute hydrochloric acid (1 M) and 10 mL of ethyl acetate (x 2) were added for extraction. The organic phases were combined, dried, and concentrated to obtain crude product 5. 3 mL of HCl / 1,4-dioxane (4 M) solution was added to crude product 5, and the mixture was stirred at room temperature for 40 min, and the reaction was monitored by TLC. After the reaction was complete, most of the solvent was removed under reduced pressure. Diethyl ether was slowly added dropwise to precipitate the product. After centrifugation, 124 mg (0.365 mmol) of the target product 6, namely dipeptide-2, was obtained, with a yield of 92%.

[0041]

[0042] 1 H NMR (300 MHz, DMSO-d6) δ 12.78 (s, 1H), 11.08 (s, 1H), 8.94 (d, J =6.8 Hz, 1H), 8.30 (s, 3H), 7.55 (d, J = 7.6 Hz, 1H), 7.51 – 7.20 (m, 2H),7.18 – 6.87 (m, 2H), 4.52 (q, J = 6.9 Hz, 1H), 3.74 (t, J = 5.1 Hz, 2H), 3.28– 2.97 (m, 2H), 2.30 – 2.07 (m, 1H), 1.13 – 0.81 (m, 6H).

[0043] 13 C NMR (75 MHz, DMSO-d6) δ 173.2, 168.5, 136.5, 127.5, 124.6, 121.3,118.8, 118.5, 111.9, 109.7, 66.8, 57.3, 53.7, 30.4, 27.3, 18.7, 18.1.

[0044] The dipeptide-2 prepared in Example 1 was analyzed by HPLC, and the results are as follows: Figure 1 As shown, the preparation method of the present invention can obtain high-purity dipeptide-2.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing dipeptide-2, characterized in that, Includes the following steps: Step (1): Dissolve compound 1 and compound 4 in solvent I, add base a, and react at 15-30℃ for 10-20 min. Then slowly add compound 2 and react at 15-30℃ for 10-20 min. After the reaction is complete, extract, dry and separate to obtain compound 3. The reaction equation for step (1) is as follows: Step (2): Dissolve compound 3 in solvent II, add base b to react, and after the reaction is complete, extract and distill under reduced pressure to obtain crude product 5; add acid to crude product 5 to react, and after the reaction is complete, distill under reduced pressure, recrystallize and centrifuge to obtain compound 6, namely dipeptide-2; The reaction equation for step (2) is as follows: In step (1), compound 1 is N-tert-butoxycarbonyl-L-valine, compound 4 is tetrafluorophthalonitrile, base a is N,N-diisopropylethylamine, solvent I is N,N-dimethylformamide, and compound 2 is L-tryptophan methyl ester.

2. The method for preparing dipeptide-2 according to claim 1, characterized in that, In step (1), the molar ratio of compound 1, compound 4 and base a is 1:1-1.5:1-1.5; the molar ratio of compound 1 to compound 2 is 1:1-1.

5.

3. The method for preparing dipeptide-2 according to claim 1, characterized in that, In step (2), the base b is NaOH, the solvent II is methanol, the acid is 4M HCl / 1,4-dioxane solution, and the recrystallization solvent is diethyl ether.

4. The method for preparing dipeptide-2 according to claim 1, characterized in that, In step (2), the reaction temperature is 15-30℃; the reaction time of compound 3 with base b is 25-40 min, and the reaction time of crude product 5 with acid is 25-40 min.

5. The method for preparing dipeptide-2 according to claim 1, characterized in that, In step (2), the mass ratio of compound 3 to base b is 3-4:1; the mass ratio of compound 3 to acid is 1:15-18.

6. The method for preparing dipeptide-2 according to claim 1, characterized in that, In step (1), the amount of solvent I added is 1-2 times the mass of compound 1; in step (2), the amount of solvent II added is 10-12 times the mass of compound 3.

7. The method for preparing dipeptide-2 according to claim 1, characterized in that, In both steps (1) and (2), the reaction process was monitored using thin-layer chromatography.

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