Synthetic method of fused epoxy glycoside and application of fused epoxy glycoside in pharmacy

Abstract

The invention provides a synthetic method of condensed epoxy glycoside, which comprises the following steps: mixing a 1, 3-dicarbonyl compound, alkali and a 2, 3-unsaturated glycosyl donor, adding an organic solvent for reaction, monitoring the reaction process by TLC (Thin Layer Chromatography), and terminating the reaction when the 2, 3-unsaturated glycosyl donor completely disappears, thereby obtaining the condensed epoxy glycoside. The alkali used in the method is DBU, so that a condensed epoxy glycoside product with high yield and high selectivity can be generated. According to the method, after condition screening, the high-yield and high-selectivity fused epoxy glycoside can be generated by only one-step reaction without using a noble metal catalyst and only using cheap alkali, and the commercial 1, 3-dicarbonyl compound and alkali are adopted as reaction conditions, so that the cost of generating oxygen glycoside is greatly reduced.

Description

Technical Field

[0001] The invention provides a method for synthesizing a condensed ring oxygen glycoside compound, belonging to the technical field of organic synthesis. Background Art

[0002] The pyranofuran ring is part of many natural products and several drugs, and its structure is often an important component of complex molecules in the drug discovery process. There are many chemical components in the genus Pittosporum, mainly triterpenes and their glycosides, sesquiterpenes, carotenoids, sterols and other compounds according to the structural type. The crude extracts and monomer components of the genus Pittosporum have anti-tumor, antibacterial, and liver-protecting pharmacological activities. It provides a reference for the further development and utilization of the genus Pittosporum. At the same time, natural products with this mother core structure can also be used as inhibitors of HIV, which have certain pharmacological activities, but the compounds provided by the source of such products are not enough to further study their biological functions.

[0003] Miguel Adrián et al. ( Org. Lett .2021, 23 , 9227) have synthesized compounds containing this skeleton by chemical methods, which efficiently constructed natural products with a pyranofuran ring skeleton using simplified model compounds through an intramolecular [4+2] cycloaddition reaction. Although this method can obtain such compounds, it requires expensive palladium catalysts and cannot be obtained by a one-step reaction. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a simple, convenient and inexpensive method to construct a pyranofuran ring skeleton. Under the action of a base, the 1,3-dicarbonyl compound first undergoes enol interconversion, and then undergoes Michael addition with a 2,3-unsaturated glycosyl donor, and a thermodynamically stable α-fused epoxy glycoside product is obtained under elevated temperature conditions. To a certain extent, it provides a certain research basis for studying this type of compound.

[0005] A method for synthesizing α-condensed epoxy glycosides comprises the following steps: mixing a 1,3-dicarbonyl compound, a base and a 2,3-unsaturated glycoside donor, adding an organic solvent, reacting at 40-45°C, monitoring the reaction progress by TLC, and terminating the reaction when the 2,3-unsaturated sugar raw material completely disappears to obtain an α-condensed epoxy glycoside. The reaction formula is as follows:

[0006] The structural formula of R2 in the sugar acceptor is any one of an alkane, a benzene ring, a heterocycle, and a substituted benzene ring, and the substituent of the substituted benzene ring includes any one of an o-methyl group, an m-methyl group, a 4-chloro substituent, a 4-bromo substituent, thiophene, and 5,5-dimethyl-1,3-cyclohexanedione.

[0007] The group represented by R1 in the glycosyl donor is triisopropylsilyl TIPS, tert-butyldiphenylsilyl TBDPS, or tert-butyldimethylsilyl TBS.

[0008] The base includes any one of Et3N, DBU, DMAP, K2CO3, and Cs2CO3.

[0009] The solvent includes any one of dichloromethane, chloroform, acetonitrile, toluene and N,N-dimethylformamide.

[0010] The molar ratio of alkali, sugar raw material and sugar acceptor is 1:1:1.

[0011] The present invention also provides a method for synthesizing condensed ring oxygen glycosides. When the reaction temperature is room temperature, beta condensed ring oxygen glycosides are obtained.

[0012] The present invention uses the condensed epoxy glycoside prepared by the method to inhibit α-glucosidase. Based on this, the present invention also provides an application of the condensed epoxy glycoside in preparing an in vitro inhibitor for treating α-glucosidase.

[0013] The condensed ring oxygen glycosides include α-condensed ring oxygen glycosides and β-condensed ring oxygen glycosides.

[0014] In this patent, after screening of conditions, only one step of reaction is required, and no precious metal catalyst is required. Only the cheap base DBU can be used to generate high-yield and high-selectivity condensed epoxy glycosides. In addition, commercial 1,3-dicarbonyl compounds and bases are used as reaction conditions, which greatly reduces the cost of generating condensed epoxy glycosides. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the H NMR spectrum of compound 1i.

[0016] Figure 2 is the C NMR spectrum of compound 1i.

[0017] Figure 3 is the H NMR spectrum of compound 2i.

[0018] Figure 4 is the C NMR spectrum of compound 2i. DETAILED DESCRIPTION

[0019] Experimental reagents DBU, petroleum ether (boiling range 60-90 °C, Tianjin Hengxing Chemical Reagent Manufacturing Co., Ltd.), ethyl acetate (analytical grade, Tianjin Komiou Chemical Reagent Co., Ltd.), anhydrous sodium sulfate (analytical grade, Sinopharm Chemical Reagent Co., Ltd.), deuterated chloroform (deuterium atomic content 99.8%, TMS content 0.03% V / V, 10*0.5 mL / box, ARMAR, Switzerland); nuclear magnetic resonance tube (5mm 100 / pk 2 ST500-8, Norell, USA).

[0020] Experimental instruments ZXZ-4 rotary vane vacuum pump (Linhai Tanshi Vacuum Equipment Co., Ltd.), DZF-6020 vacuum drying oven (Shanghai Xinmiao Medical Equipment Manufacturing Co., Ltd.), SHB-IIIA circulating water multi-purpose vacuum pump (Shanghai Yukang Science and Education Instrument Equipment Co., Ltd.), CL-4 flat magnetic stirrer (Zhengzhou Great Wall Science and Technology Industry and Trade Co., Ltd.), EYELA SB-1100 rotary evaporator (Shanghai Ailang Instrument Co., Ltd.), FA2104B analytical balance (Shanghai Yueping Science and Technology Instrument Co., Ltd.), XRC-1 micro melting point tester (Sichuan University Science and Technology Instrument Factory), DF-101S collector constant temperature heating magnetic stirrer (Gongyi Yingyu Yuhua Instrument Factory), GZX-9240MBE digital display blast drying oven (Shanghai Boxun Industrial Co., Ltd. Medical Equipment Factory), ZF-6 three-purpose UV analyzer (Shanghai Jiapeng Technology Co., Ltd.), Ultrashied 400 MHz Plus nuclear magnetic resonance instrument (Swiss Bruker Company), API 4000 LC-MS / MS mass spectrometer (Bruker Daltonics, Germany) Example 1 Mix 1,3-dicarbonyl compound, base and 2,3-unsaturated sugar donor, add organic solvent, react at 40 ℃, monitor the reaction progress by TLC, and terminate the reaction when the 2,3-unsaturated sugar raw material disappears completely to obtain α-fused epoxy glycoside. The optimization experimental scheme of different bases and solvents is analyzed as follows:

[0021] Note: All experiments were performed by stirring 0.1 mmol of 2,3-unsaturated glycosyl donor with 0.1 mmol of 1,3-dicarbonyl compound and 0.1 mmol of base in 2 mL of solvent at 40 °C. The isolated yield was 0.1.

[0022] The reaction condition screening test showed that when acetonitrile was selected as the solvent, by screening different bases, it was found that the yield was the highest when DBU was used as the base, and a higher selectivity was obtained. In addition, after determining the base, we also screened different solvents and found that when acetonitrile was used as the solvent, a relatively high selectivity and yield could be obtained. Finally, according to the results of the condition screening, the optimal condition was determined to be DBU as the base and MeCN as the reaction solvent.

[0023] Summarizing the experimental results, the optimal conditions for the reaction of 2,3-unsaturated glycosyl donors with 1,3-dicarbonyl compounds were obtained. The best reaction effect was achieved at 40 °C with DBU as the base and MeCN as the solvent.

[0024] In the case of the above route, the present invention uses 2,3-unsaturated glycosyl donor as raw material to prepare condensed ring oxygen glycosides, and the technical route is as follows:

[0025] 2,3-Unsaturated glycosyl donor (0.1 mmol, 35.85 mg), diketone reagent (0.1 mmol, 29.31 mg), DBU (0.1 mmol, 15.20 mg) and 2 mL of acetonitrile were added to a reaction bottle for reaction at 40 °C. The reaction progress was detected by TLC. When the glycosyl raw material was completely reacted, the reaction was quenched, the organic phase was extracted and collected, and the solvent was removed by vacuum distillation to obtain a crude product. Then, petroleum ether / ethyl acetate / dichloromethane solution was used as the mobile phase for column chromatography to obtain the oxygen glycoside product (yield was 58%, α:β = 15:1). 1 H NMR (400 MHz, CDCl3) δ 7.32 – 7.27 (m, 2H), 7.13 – 7.06 (m, 6H), 6.40 (d, J = 8.8 Hz, 1H), 4.38 (ddd, J = 8.8, 5.2, 3.1 Hz, 1H), 4.20 (dd, J =3.4, 2.2 Hz, 1H), 4.12 (dd, J = 11.1, 3.4 Hz, 1H), 3.99 (dd, J = 11.1, 2.2 Hz,1H), 2.94 – 2.81 (m, 2H), 0.88 (s, 9H), 0.08 (s, 3H), 0.06 (s, 3H). 13 C NMR (100 MHz, CDCl3) δ209.6, 190.4, 162.9, 138.5, 137.0, 136.6, 130.2, 128.4,128.3, 126.8, 112.9, 101.7, 78.5, 63.2, 43.3, 37.3, 29.7, 25.8, 18.3, -5.4, -5.5. The following products were also prepared under the reaction conditions:

[0026] Activity evaluation The enzyme α-glucosidase was used in the experiment to inhibit the activity of the enzyme in vitro, and the inhibitory activity of multiple compounds on α-glucosidase was detected. Acarbose was used as a positive drug. The reaction solution was prepared, and the sample and positive drug were dissolved in DMSO, and the compound concentrations were 90, 30, and 10 μM, respectively.

[0027] α-glucosidase in vitro inhibitory activity, detect the inhibitory activity of multiple compounds on α-glucosidase. The experiment was divided into enzyme activity group (α-glucosidase solution and buffer solution), enzyme blank group (buffer and sample), positive group (α-glucosidase solution and positive drug solution), positive blank group (buffer solution and positive drug solution), sample group (α-glucosidase solution and sample) and sample blank group (buffer solution and sample). For the above groups, we carried out corresponding research. First: accurately weigh 1-2 mg of sample and positive drug (acarbose), dissolve them with dimethyl sulfoxide (DMSO) respectively, and then dilute the sample solution to the corresponding concentration with PBS buffer solution (0.1 mol / mL, pH = 6.8); second: use a standard pipette to accurately measure 15μL of sample and 45μL of α-glucosidase solution (0.3μL / mL) and add them to a 96-well plate, shake and mix for 4 minutes to mix them completely. Then preheat at 37°C, add 20 μL substrate (PNPG) solution, shake and mix evenly, and react at 37°C for half an hour; third: add 100 μL Na2CO3 solution to terminate the reaction. Finally, the inhibitory activity of the sample is obtained by measuring the absorbance OD at 405nm.

[0028] Table 1 shows the test results of the compounds.

[0029] Table 1: Test results of compounds

[0030] Example 2 Mix 1,3-dicarbonyl compound, base and 2,3-unsaturated sugar donor, add organic solvent, react at room temperature, monitor the reaction progress by TLC, and terminate the reaction when the 2,3-unsaturated sugar raw material disappears completely to obtain β-fused epoxy glycoside. The optimization experimental scheme of different bases and solvents is analyzed as follows:

[0031] Note: All experiments were performed with 0.1 mmol of 2,3-unsaturated glycosyl donor, 0.1 mmol of 1,3-dicarbonyl compound and 0.1 mmol of base in 2 mL of solvent under stirring at room temperature. The isolated yield was . The reaction condition screening test shows that when acetonitrile is selected as the solvent, by screening different bases, it can be obtained that the yield is the highest when cesium carbonate is used as the base, but a higher selectivity is not obtained. To improve the selectivity, we also screened the same type of potassium carbonate and found that a relatively high selectivity can be obtained, but a higher yield is not obtained. In order to improve the yield, we started from the solvent and screened different types of solvents. It was found that when DMF was used as the solvent, a higher yield and selectivity could be obtained. Finally, according to the results of the condition screening, the optimal conditions were determined to be potassium carbonate as the base and DMF as the reaction solvent.

[0032] Summarizing the experimental results, the optimal conditions for the reaction of 2,3-unsaturated glycosyl donors with 1,3-dicarbonyl compounds were obtained. The best reaction effect was achieved at room temperature with K2CO3 as the base and N,N-dimethylformamide as the solvent.

[0033] In the case of the above route, the present invention uses 2,3-unsaturated glycosyl donor as raw material to prepare condensed ring oxygen glycosides, and the technical route is as follows:

[0034] 2, 3-unsaturated glycosyl donor (0.1 mmol, 35.85 mg), diketone reagent (0.1 mmol, 14.01 mg), potassium carbonate (0.1 mmol, 1.82 mg) and 2 mL of DMF were added to the reaction bottle for room temperature reaction. The reaction progress was detected by TLC. When the glycosyl raw material was completely reacted, the reaction was quenched, the organic phase was extracted and collected, and the solvent was removed by vacuum distillation to obtain a crude product. Then, petroleum ether / ethyl acetate / dichloromethane solution was used as the mobile phase for column chromatography to obtain the oxygen glycoside product (yield was 89%, β:α>20:1). mp: 115-118 °C; 1 H NMR (400 MHz, Chloroform- d ) δ 5.95 (d, J=7.4 Hz, 1H), 4.03 (s, 3H), 3.56 – 3.48 (m, 1H), 2.97 (dd, J = 14.0, 6.8 Hz,1H), 2.68 (dd, J = 14.1, 8.9 Hz, 1H), 2.36 (d, J = 2.0 Hz, 2H), 2.23 (s, 2H), 1.10 (s, 3H), 1.10 (s, 3H), 1.06 – 0.98 (m, 21H). 13 C NMR (100 MHz, Chloroform- d ) δ 209.1, 194.2, 174.1, 114.0, 104.6, 82.0, 63.9, 51.1, 39.0, 38.9, 37.4,34.2, 28.9, 28.3, 17.9, 11.9. The following products were also prepared under the reaction conditions:

[0035] Activity evaluation The enzyme α-glucosidase was used in the experiment to inhibit the activity of the enzyme in vitro, and the inhibitory activity of multiple compounds on α-glucosidase was detected. Acarbose was used as a positive drug. The reaction solution was prepared, and the sample and positive drug were dissolved in DMSO, and the compound concentrations were 90, 30, and 10 μM, respectively.

[0036] α-glucosidase in vitro inhibitory activity, detect the inhibitory activity of multiple compounds on α-glucosidase. The experiment was divided into enzyme activity group (α-glucosidase solution and buffer solution), enzyme blank group (buffer and sample), positive group (α-glucosidase solution and positive drug solution), positive blank group (buffer solution and positive drug solution), sample group (α-glucosidase solution and sample) and sample blank group (buffer solution and sample). For the above groups, we carried out corresponding research. First: accurately weigh 1-2 mg of sample and positive drug (acarbose), dissolve them with dimethyl sulfoxide (DMSO) respectively, and then dilute the sample solution to the corresponding concentration with PBS buffer solution (0.1 mol / mL, pH = 6.8); second: use a standard pipette to accurately measure 15μL of sample and 45μL of α-glucosidase solution (0.3μL / mL) and add them to a 96-well plate, shake and mix for 4 minutes to mix them completely. Then preheat at 37°C, add 20 μl of substrate (PNPG) solution, shake and mix evenly, and react at 37°C for half an hour; third: add 100 μl of Na2CO3 solution to terminate the reaction. Finally, the inhibitory activity of the sample is obtained by measuring the absorbance OD at 405nm.

[0037] Table 1 shows the test results of the compounds.

[0038] Table 1: Test results of compounds

Claims

1. A method for synthesizing condensed epoxy glycosides, characterized in that: The method comprises the following steps: mixing a 1,3-dicarbonyl compound, a base and a 2,3-unsaturated glycoside donor, adding an organic solvent, reacting at 40-45° C., monitoring the reaction progress by TLC, and terminating the reaction when the 2,3-unsaturated glycoside raw material completely disappears to obtain an α-condensed epoxy glycoside. The reaction formula is as follows: ， The structural formula of R2 in the sugar acceptor is any one of an alkane, a benzene ring, a heterocycle, and a substituted benzene ring, and the substituent of the substituted benzene ring includes any one of an o-methyl group, an m-methyl group, a 4-chloro substituent, a 4-bromo substituent, thiophene, and 5,5-dimethyl-1,3-cyclohexanedione.

2. The method for synthesizing condensed ring oxygen glycosides according to claim 1, characterized in that: The group represented by R1 in the glycosyl donor is triisopropylsilyl TIPS, tert-butyldiphenylsilyl TBDPS, or tert-butyldimethylsilyl TBS.

3. The method for preparing a condensed ring oxygen glycoside compound according to claim 1, characterized in that: The base includes any one of Et3N, DBU, DMAP, K2CO3, and Cs2CO3.

4. The method for synthesizing condensed ring oxygen glycosides according to claim 1, characterized in that: The solvent includes any one of dichloromethane, chloroform, acetonitrile, toluene and N,N-dimethylformamide.

5. The method for synthesizing condensed ring oxygen glycosides according to claim 1, characterized in that: The molar ratio of alkali, sugar raw material and sugar acceptor is 1:1:

1.

6. The method for synthesizing the condensed ring oxygen glycoside according to any one of claims 1 to 5, characterized in that: When the reaction temperature is room temperature, β-fused epoxy glycoside is obtained.

7. Use of a condensed epoxy glycoside prepared by the method according to any one of claims 1 to 6 in the preparation of an in vitro inhibitor for treating α-glucosidase.

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