Direct synthesis method of unprotected thioglycoside and medicine for treating diabetes mellitus by using unprotected thioglycoside

Abstract

The invention discloses a direct synthesis method of unprotected thioglycoside and a medicine for treating diabetes mellitus by using the unprotected thioglycoside. The invention provides a direct synthesis method of unprotected thioglycoside, which comprises the following steps: adding a sugar donor, disulfide and zinc powder into a Schlenk tube, adding a titanium catalyst, a chlorosilane additive and a molecular sieve into a glove box after 20 minutes by using an oil pump, injecting a solvent under N2 atmosphere, stirring at 50-60 DEG C, detecting the reaction process by using TLC (Thin Layer Chromatography), terminating the reaction when the sugar raw material completely disappears, and filtering to obtain the unprotected thioglycoside. Filtering to remove solid impurities, extracting and collecting an organic phase, carrying out reduced pressure distillation to remove a solvent to obtain a crude product, and then carrying out column chromatography by taking a petroleum ether / ethyl acetate / dichloromethane / methanol solution as a mobile phase to obtain the unprotected thioglycoside. The catalyst used in the invention is CpTiCl3, has high reducing ability and selectivity, and can effectively crack C-OH bonds and generate anomeric free radicals to ensure high efficiency and stereoselectivity of the reaction, so that the alpha-configuration unprotected thioglycoside can be obtained.

Description

Technical Field

[0001] A direct synthesis method for unprotected glucosinolates and its application in pharmaceuticals belongs to the field of organic synthesis technology. Background Technology

[0002] Carbohydrates not only serve as an energy source for human life activities but also play a crucial role in numerous physiological and pathological processes. Among them, thioglycosides are a class of compounds in which the oxygen atom in the glycoside molecule is replaced by a sulfur atom, with the general structural formula glycosyl- S - Ligands. These compounds have broad research significance in biological life activities and medicine. For example: sucrase... CS Bond stability (compared to) O - Glycosidic bonds are more resistant to acid hydrolysis and enzymatic degradation, and are often used as tool molecules in glycosylation research to mimic the roles of glycoproteins or glycolipids in cell recognition and signal transduction; thioglycosides can competitively inhibit glycosidases (such as... β Glucosides, also known as thioglycosides, interfere with the sugar metabolism of pathogens (such as Plasmodium) or host-pathogen interactions. Furthermore, they have made significant contributions to antiviral and antitumor research: some thioglycoside analogs can inhibit bacterial peptidoglycan synthesis (such as Mycobacterium tuberculosis) or viral glycosidases (such as neuraminidase in HIV and influenza viruses); thioglycoside derivatives (such as sulforaphane) exert antioxidant and anticancer effects by activating the Nrf2 / ARE pathway, or induce tumor cell apoptosis (such as in colorectal cancer and prostate cancer). Due to their unique chemical properties and biological activities, thioglycosides are of great value in the fields of natural product function research, drug development (anticancer, anti-infection, metabolic diseases), and glycobiology tool molecules.

[0003] Traditional thioglycoside synthesis typically requires the protection and deprotection of the hydroxyl groups in sugar molecules, a process that is quite cumbersome and complex. However, in recent years, unprotected thioglycoside synthesis strategies have attracted widespread attention due to their high efficiency, atom economy, and green chemistry advantages. For example, in 2021, Professor Lei Li of Georgia State University developed a method for synthesizing unprotected thioglycosides using unprotected fluorinated sugars as sugar donors. Green Chem. (2021, 23, 2907), but this method still requires a multi-step pre-synthesis to convert the terminal group (position 1) of the natural sugar into fluorine, which means that a specific stereoconfiguration of the unprotected fluorinated sugar donor is required beforehand, and unprotected all-hydroxy natural sugars cannot be used directly as raw materials; in addition, three equivalents of fluorinated sugar are required as sugar donors and three equivalents of calcium hydroxide as promoters to mediate the reaction, and the catalytic amount of reaction construction has not yet been achieved. Therefore, the reported methods for the synthesis of thioglycosides still have problems such as cumbersome protection-deprotection synthesis steps, low atom economy, and stereoselectivity that need to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a simple and efficient method for synthesizing unprotected glucosinolates, comprising the following steps: The sugar donor, disulfide, and zinc powder were added to a Schlenk tube. After pumping for 20 minutes, titanium catalyst, chlorosilane additive, and molecular sieve were added in a glove box. Solvent was injected under a nitrogen atmosphere, and the mixture was stirred at 20-90°C. The reaction progress was monitored by TLC. The reaction was terminated when the sugar raw material was completely eliminated to obtain unprotected glucosinolates. The reaction formula is as follows: ; The reaction process includes a post-processing step, which involves filtering to remove solid impurities, extracting and collecting the organic phase, removing the solvent by vacuum distillation to obtain the crude product, and then performing column chromatography using a petroleum ether / ethyl acetate / dichloromethane / methanol solution as the mobile phase to obtain unprotected glucosinolates.

[0005] The catalyst includes any one of CpTiCl3, Cp2TiCl2, Cp*TiCl3, and Ti(OTf)3.

[0006] The additives include any one of Me3ClSi, H3SiCl, Me2PhClSi, and Me2BnSiCl.

[0007] The solvent includes any one of THF, DMC, 2-MeTHF, and 1,4-Dioxane.

[0008] The reaction temperature is 25-90°C, and includes any value within 25-90°C. In some preferred embodiments, the temperature range includes one of room temperature, 45°C, 60°C, 75°C, and 90°C.

[0009] The unprotected sugar donors include any one of D-glucose, D-galactose, D-mannose, L-rhamnose, and L-arabinose.

[0010] The structure of R in the sugar acceptor disulfide is a benzene ring and a substituted benzene ring, wherein the substituents of the substituted benzene ring include any one of 4-methyl substituent, 4-methoxy substituent, 4-ethyl substituent, ortho-, meta-, and para-halogen substituents. The molar ratio of the sugar donor, catalyst, additive, and sugar acceptor is 1.0:0.1-0.2:0.5-7.0:1.0, preferably 1.0:0.2:7.0:1.0.

[0011] This invention features relatively mild conditions, good innovation, and high stereoselectivity. Taking Cp*TiCl3 as an example, the catalytic reaction process is explained. In this process, Zn powder reduces Cp*TiCl3 to the active substance Cp*TiCl2. Due to the higher stability of the anodic radical of the sugar ring, the anodic hydroxyl group is selectively activated and coordinates with Cp*TiCl2 to form Cp*Ti(OH)Cl2. Cp*Ti(OH)Cl2 then undergoes halogen exchange with a chlorosilane to regenerate Cp*TiCl3, completing the catalytic cycle. Simultaneously, a glycosyl radical forms at the first position of the sugar ring and couples with a thiophenol radical to generate an unprotected glucosinolate. Furthermore, there is no need to protect the hydroxyl group of the sugar donor or convert it into a special sugar donor, greatly shortening the reaction steps and significantly improving production efficiency and saving production costs. Finally, the synthesized unprotected glucosinolate exhibits good stability and has great value in drug synthesis. Attached Figure Description

[0012] Figure 1 : The proton spectrum of compound 3a.

[0013] Figure 2 : Carbon spectrum of compound 3a. Detailed Implementation

[0014] Experimental reagents Cyclopentadienyl titanium trichloride (Anhui Leyan Biomedical Technology Co., Ltd.), dimethylphenylchlorosilane (Anhui Leyan Biomedical Technology Co., Ltd.), petroleum ether (boiling range 60-90 ℃, Tianjin Hengxing Chemical Reagent Manufacturing Co., Ltd.), dichloromethane (analytical grade, Tianjin Kemio Chemical Reagent Co., Ltd.), ethyl acetate (analytical grade, Tianjin Kemio Chemical Reagent Co., Ltd.), anhydrous sodium sulfate (analytical grade, Sinopharm Chemical Reagent Co., Ltd.), deuterated acetone (99.9% deuterium content, 0.03% TMS content, 10g / bottle, Shanghai Maclean Biochemical Technology Co., Ltd.), deuterated methanol (99.8% deuterium content, 0.03% TMS content, 25mL / bottle, Beijing Bailingwei Technology Co., Ltd.); NMR tube (5mm 100 / pk 2 ST500-8, Norell Corporation, USA).

[0015] Experimental instruments ZXZ-4 Rotary Vane Vacuum Pump (Linhai Tanshi Vacuum Equipment Co., Ltd.), DZF-6020 Vacuum Drying Oven (Shanghai Xinmiao Medical Instrument Manufacturing Co., Ltd.), SHB-IIIA Circulating Water Multipurpose Vacuum Pump (Shanghai Yukang Science and Education Instrument Equipment Co., Ltd.), CL-4 Flat Plate Magnetic Stirrer (Zhengzhou Changcheng Science and Industry 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 Scientific Instrument Factory), DF-101S Heat Collector-type Constant Temperature Heating Magnetic Stirrer (Gongyi Yingyu Yuhua Instrument Factory), GZX-9240MBE Digital Display Blower Drying Oven (Shanghai Boxun Industrial Co., Ltd. Medical Equipment Factory), ZF-6 Three-Purpose Ultraviolet Analyzer (Shanghai Jiapeng Technology Co., Ltd.), Ultrashied 400 MHz Plus Nuclear Magnetic Resonance Spectrometer (Bruker AG, Switzerland), API 4000 LC-MS / MS mass spectrometer (Bruckdorf Dalton GmbH, Germany) Example 1 D-glucose (36.32 mg, 0.2 mmol), diphenyl disulfide (43.7 mg, 0.2 mmol), and zinc powder (39.2 mg, 0.6 mmol) were added to a 5 mL Schlenk tube. After pumping for 20 min, pentamethylcyclopentadienyl titanium trichloride (Cp*TiCl3, 11.6 mg, 0.04 mmol), dimethylphenylchlorosilane (Me2PhSiCl, 238.9 mg, 1.4 mmol), and molecular sieve (5 Å, 20 mg) were added to a glove box. Finally, under N2 protection, 1 mL of redistilled THF was added using a syringe. The entire experiment was conducted under anhydrous and oxygen-free conditions, with stirring at 60 degrees Celsius for 12 hours. The reaction progress was monitored by TLC. After the glucose raw material was completely eliminated, the reaction solution was filtered to remove solid impurities. The filtrate was quenched with water and extracted with DCM. The organic phase was distilled under reduced pressure to obtain an oily crude product. Then, column chromatography was performed using a petroleum ether / ethyl acetate / methanol / dichloromethane solution as the mobile phase to obtain (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(phenylthio)tetrahydro-2H-pyran-3,4,5-triol (yield 54%).

[0016] Regarding the above process, this invention takes D-glucose as an example and optimizes the catalyst, solvent, additives, and temperature. The screening conditions are shown in Table 1: Table 1

[0017] Note: All experiments were conducted using 0.2 mmol D-glucose with 0.2 mmol diphenyl disulfide, 0.04 mmol titanium catalyst, 0.6 mmol zinc powder, 1.4 mmol dimethylphenylchlorosilane, and 10 mg 5 Å molecular sieve in 1 mL solvent at 60 °C under stirring. The reaction was carried out in an anhydrous and oxygen-free environment. The yield and stereoselectivity were determined by 1H NMR spectroscopy.

[0018] Reaction condition screening experiments showed that using D-glucose as the glycosyl donor and diphenyl disulfide as the acceptor was optimal (Table 1). First, Cp*TiCl3 was selected as the catalyst, Me2PhSiCl as the additive, and THF as the solvent to verify my hypothesis. Fortunately, the reaction proceeded smoothly, and unprotected glucosinolate was successfully synthesized in 54% yield at an isomer ratio of 6.9:1. Then, other titanium catalysts, including Cp*TiCl3, CpTiCl3, Cp2TiCl2, and Ti(OTf)3, were screened, all showing good technical performance. Finally, the optimal reaction conditions were determined to be CpTiCl3 as the catalyst, THF as the solvent, Me2PhSiCl as the additive, and a reaction temperature of 60℃.

[0019] The experimental results show that the optimal reaction conditions for unprotected glucosinolates are 60℃ with CpTiCl3 as the catalyst, dimethylphenylchlorosilane as the additive, and tetrahydrofuran as the solvent.

[0020] Example 2 This invention uses D-glucose as a raw material and diphenyl disulfide as a sugar acceptor to prepare (2) R ,3 S 4 S 5 R 6 R )-2-(hydroxymethyl)-6-(phenylthio)tetrahydro-2 H -Pyran-3,4,5-triol, the technical route is as follows:

[0021] D-glucose (36.32 mg, 0.2 mmol), diphenyl disulfide (43.7 mg, 0.2 mmol), and zinc powder (39.2 mg, 0.6 mmol) were added to a 5 mL Schlenk tube. After pumping for 20 min, cyclopentadienyl titanium trichloride (CpTiCl3, 8.8 mg, 0.04 mmol), dimethylphenylchlorosilane (Me2PhSiCl, 238.9 mg, 1.4 mmol), and molecular sieve (5 Å, 20 mg) were added to a glove box. Finally, under N2 protection, 1 mL of redistilled THF was added using a syringe. The entire experiment was conducted under anhydrous and oxygen-free conditions, with stirring at 60°C for 12 hours. The reaction progress was monitored by TLC. After the glucose raw material completely disappeared, the reaction solution was filtered to remove solid impurities. The filtrate was quenched with water and extracted with DCM. The organic phase was then distilled under reduced pressure to obtain an oily crude product, which was then subjected to column chromatography using a petroleum ether / ethyl acetate / methanol / dichloromethane solution as the mobile phase to obtain (2... R ,3 S 4 S 5 R 6 R )-2-(hydroxymethyl)-6-(phenylthio)tetrahydro-2 H -Pyran-3,4,5-triol (yield 72%).

[0022] The (2) prepared in Example 2 above R ,3 S 4 S 5 R 6 R )-2-(hydroxymethyl)-6-(phenylthio)tetrahydro-2 H 1H and 1C spectral data of pyran-3,4,5-triol 1 H NMR (400 MHz, Acetone- d 6) δ 7.56 – 7.52(m, 2H), 7.33 – 7.28 (m, 2H), 7.27 – 7.22 (m, 1H), 5.57 (d, J = 5.2 Hz, 1H), 4.49 (d, J = 4.8 Hz, 1H), 4.42 – 4.35 (m, 2H), 4.07 (ddd, J = 9.6, 4.8, 3.2. Hz,1H), 3.82 – 3.72 (m, 3H), 3.62 – 3.55 (m, 2H), 3.45 (ddd, J = 9.6, 8.8, 4.8 Hz, 1H).13 C{ 1 H} NMR (100 MHz, Acetone- d 6) δ HRMS (ESI) m / z : calcd for C 12 H 17 O5S + (M + H) + 273.0791, found, 273.0799; = -16.751 ( c = 1.0, CHCl3). The following products were also prepared under these reaction conditions:

[0023] Activity evaluation The in vitro inhibitory activity of the enzyme α-glucosidase was tested, and the inhibitory activity of multiple compounds against α-glucosidase was detected. Acarbose was used as a positive control. For reaction solution preparation, the samples and positive control were dissolved in DMSO at concentrations of 90, 30, and 10 μM.

[0024] In vitro inhibitory activity of α-glucosidase was investigated, and the inhibitory activity of multiple compounds on α-glucosidase was detected. The experiment was divided into four groups: enzyme activity group (α-glucosidase solution and buffer solution), enzyme blank group (buffer solution 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 each group, we conducted the corresponding research. First, 1-2 mg of sample and positive drug (acarbose) were accurately weighed and dissolved separately in dimethyl sulfoxide (DMSO), and then the sample solution was diluted to the corresponding concentration with PBS buffer (0.1 mol / mL, pH = 6.8). Second, 15 μL of sample and 45 μL of α-glucosidase solution (0.3 μL / mL) were accurately pipetteted into a 96-well plate and mixed by shaking for 4 minutes to ensure complete mixing. The mixture was then preheated at 37 °C, and 20 μl of substrate (PNPG) solution was added. The mixture was shaken to mix thoroughly and reacted at 37 °C for half an hour. Third, 100 μl of Na₂CO₃ solution was added to terminate the reaction. Finally, the inhibitory activity of the sample was determined by measuring the absorbance (OD) at 405 nm.

[0025] Table 2 shows the determination results of the compounds.

[0026] .

Claims

1. A method for synthesizing unprotected glucosinolates, characterized in that, The process includes the following steps: A sugar donor, a sugar acceptor disulfide derivative, and zinc powder are added to a Schlenk tube. After oil removal, a titanium catalyst, a chlorosilane additive, and a molecular sieve are added in a glove box. Solvent is injected under N2 protection, the reaction is stirred, and the reaction progress is monitored by TLC. The reaction is terminated when the sugar raw material has completely disappeared to obtain unprotected glucosinolates. The reaction formula is as follows: 。 2. The method for synthesizing unprotected glucosinolates according to claim 1, characterized in that, The catalyst includes any one of CpTiCl3, Cp2TiCl2, Cp*TiCl3, and Ti(OTf)3.

3. The method for synthesizing unprotected thioglycoside compounds according to claim 1, characterized in that, The additives include any one of Me3ClSi, H3SiCl, Me2PhClSi, and Me2BnSiCl.

4. The method for synthesizing unprotected glucosinolates according to claim 1, characterized in that, The solvent includes any one of THF, DMC, 2-MeTHF, and 1,4-Dioxane.

5. The method for synthesizing unprotected thioglycoside compounds according to claim 1, characterized in that, The reaction temperature is 25-90℃.

6. The method for synthesizing unprotected thioglycoside compounds according to claim 1, characterized in that, The unprotected sugar donor includes any one of D-glucose, D-galactose, D-mannose, L-rhamnose, and L-arabinose. The structure of R in the sugar acceptor disulfide derivative is a benzene ring and a substituted benzene ring. The substituents of the substituted benzene ring include any one of 4-methyl substituent, 4-methoxy substituent, 4-ethyl substituent, and ortho, meta, or para halogen substituents.

7. The method for synthesizing unprotected thioglycoside compounds according to claim 1, characterized in that, The molar ratio of the sugar donor, catalyst, additive, and sugar acceptor is 1.0:0.1-0.2:0.5-7.0:1.

0.

8. An unprotected glucosinolate compound, characterized in that, The unprotected thioglycoside compound obtained by the synthetic method according to any one of claims 1-7 has a structural formula comprising any one of the following: 。 9. A drug for inhibiting α-glucosidase activity, characterized in that, The drug comprises the unprotected glucosinolate compound of claim 8.

10. A drug for diabetes, characterized in that, The drug comprises the unprotected glucosinolate compound of claim 8.

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