A selenoglycoside compound and a synthesis method thereof

Abstract

The application discloses a selenoglycoside compound and a synthesis method, and aims at a series of technical defects in the existing selenoglycoside synthesis technology, such as high reagent toxicity, strong irritability, poor stability, harsh reaction conditions, complicated operation, insufficient stereoselectivity, poor substrate universality and difficulty in industrial application, and provides a green and efficient selenoglycoside compound synthesis method with strong universality, which has remarkable beneficial technical effects. The core reaction substrate adopted in the application is a glycosyl selenosulfonate and a (hetero) aryl boronic acid, both of which are conventional reagents easy to obtain, have no irritating odor, and have excellent chemical stability and environmental tolerance, thereby avoiding the use of high-toxicity, high-irritability and low-stability reagents such as diselenide, selenol and glycosyl stannane in the traditional synthesis process from the source, greatly reducing the safety control cost and three-waste treatment pressure in the synthesis process, and meeting the development requirements of green chemistry.

Description

Technical Field

[0001] This invention relates to the field of medicinal chemistry, specifically to a selenoglycoside compound and its synthesis method. Background Technology

[0002] Selenoglycosides, as bioisosteres of oxyglycosides and thioglycosides, exhibit good stability against glycoside hydrolases and possess bioactivities such as anti-metastasis, anti-tumor, and immunostimulatory effects, making them an important class of carbohydrate derivatives. Selenoglycosides can also serve as glycosylation donors and have been successfully applied in the synthesis of oligosaccharides, glycoconjugates, oxyglycosides, and carbon glycosides. Furthermore, they are utilized... 77 SeNMR, selenoglycosides can also be designed as probe molecules for studying the structure of carbohydrate-protein complexes. On the other hand, glycosyl selenoglycoside donors are similar in properties to thioglycosides, but with higher reactivity. Selenoglycosides, as glycosyl donors, possess unique reactivity. Currently, common activation methods for selenoglycosides include thiophilic / selenyl reagent activation and photocatalysis, which break the carbon-selenium bond, leading to glycosylation. Therefore, selenoglycosides have potential synthetic applications and pharmaceutical research value. Thus, developing a simple and universal method for preparing selenoglycosides is of great significance.

[0003] Several common chemical synthesis methods for preparing selenoglycosides all have certain limitations. There are three main types of synthetic methods for aryl selenoglycosides. The first type involves nucleophilic substitution of a 1-halosugar with a nucleophilic selenophilic reagent to prepare selenoglycosides. For example, Romanò developed a method to synthesize selenoglycosides by reducing diselenide compounds under reducing conditions to generate selenium anions that attack electrophilic glycosides. However, this method requires the use of toxic, unstable, and irritating diselenide reagents (…). J. Carbohydr. Chem. 1996, 15, 183). The second method involves synthesizing selenoglycosides through the reaction of glycosyl selenosides with electrophilic reagents. For example, Kawai utilized base activation of β-p-methylbenzoyl selenoglycoside to form glycosyl selenosides in situ, which then reacted with various electrophilic reagents to prepare a series of alkyl / aryl selenoglycosides. While this method exhibits good stereoselectivity and substrate applicability, glycosyl selenosides are easily oxidized and dimerized, and the method has low compatibility with heterocyclic substrates. Org. Lett. 2005, 7, 4653). In 2021, Ding used a palladium / norbornene catalytic system to convert benzoyl selenoside and aryl iodine into a series of selenoglycosides. However, the aryl iodine substrate for this reaction is highly limited, requiring cyclic or polysubstituted aryl iodine to avoid secondary selenoglycosylation. Furthermore, the reaction requires a noble palladium catalyst and inert gas protection, and the high reaction temperature and long reaction time significantly limit its synthetic applications. Org. Lett.2021, 23, 5641). The third type of method is the metal-mediated coupling reaction of glycosyl nucleophiles (such as glycosylstananes and glycosyl fluoroborates) with diselenide compounds. Zhu et al. utilized stoichiometric copper salts to mediate the coupling of glycosylstananes with symmetrical diselenides (…). Angew. Chem. Int. Ed. (2018, 57, 7091). However, this method requires a high reaction temperature (110°C), and the synthesis of glycosyltinanes is cumbersome, requiring the use of toxic tin reagents, which greatly limits its wide synthetic application. Therefore, developing a new, efficient, and stereoselective method for the synthesis of selenoglycosides has significant application value. Summary of the Invention

[0004] To address the aforementioned shortcomings of the prior art, this invention provides a selenoglycoside compound and a method for its synthesis.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A selenoglycoside compound is provided, with the structural formula shown in Formula I below;

[0006] I Wherein, R1 is Ac or H; R2 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

[0007] Furthermore, the selenoglycoside compound is any one of the following compounds;

[0008]

[0009] In compound 2a, R1 is Ac and R2 is phenyl; in compound 2b, R1 is Ac and R2 is 4-methoxyphenyl; in compound 2c, R1 is Ac and R2 is 4-chlorophenyl; in compound 2d, R1 is Ac and R2 is 3-bromophenyl; in compound 2e, R1 is Ac and R2 is 4-acetylphenyl; in compound 2f, R1 is Ac and R2 is 4-isopropylsulfonylphenyl; in compound 2g, R1 is Ac and R2 is 4-formylphenyl; and in compound 2h, R1 is Ac and R2 is 2,4- Dimethylphenyl; in compound 2i, R1 is Ac and R2 is 2-chloro-4-methylphenyl; in compound 2j, R1 is Ac and R2 is 2-methyl-4-methoxyphenyl; in compound 2k, R1 is Ac and R2 is 2-methoxy-4-fluorophenyl; in compound 2l, R1 is Ac and R2 is 9,9-dimethylfluorene-2-yl; in compound 2m, R1 is Ac and R2 is dibenzofuran-4-yl; in compound 2n, R1 is Ac and R2 is phenoxazine-4-yl; in compound 2o, R1 is Ac and R2 is... N-Boc-indol-2-yl; R1 of compound 2p is Ac, and R2 is phenoxathio-4-yl; R1 of compound 2q is Ac, and R2 is 3-acetamidophenyl; R1 of compound 2r is H, and R2 is 2-(4-methoxybenzyl)phenyl; H of compound 2s is Ac, and R2 is 2-((2-(4-fluorophenyl)thiophen-5-yl)methyl)phenyl; R1 of compound 2t is H, and R2 is 2-chloro-6-(4-(((S)-tetrahydrofuran-3-yl)oxy)benzyl)phenyl.

[0010] This invention also provides a method for synthesizing the above-mentioned selenoglycoside compounds. When preparing any one of compounds 2a to 2q, the following specific steps are adopted: A1: Dissolve selenoglycoside donor, selenoglycoside acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; A2: After the reaction is complete, dilute with ethyl acetate, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate the solvent, and finally purify by column chromatography to obtain any one of the selenoglycoside compounds 2a~2q. The following specific steps are used to prepare any one of compounds 2r to 2t: B1: Dissolve selenoglycosylate donor, selenoglycosylate acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; B2: After the reaction was completed, the mixture was diluted with ethyl acetate, washed with water, dried with anhydrous sodium sulfate, the solvent was evaporated, and finally purified by column chromatography to obtain the selenoglycoside intermediate. B3: Dissolve the selenoglycoside intermediate in methanol, add sodium methoxide, react at room temperature for 1 hour, add acidic resin to adjust the pH to 7-8, filter, evaporate the solvent, and purify by column chromatography to obtain any one of the selenoglycoside compounds 2r-2t.

[0011] Furthermore, in steps A1 and B1, the molar ratio of selenoglycosylate donor, selenoglycosylate acceptor, silver nitrate, and N,N-diisopropylethylamine is 1:1.2:0.1:2.

[0012] Furthermore, in steps A1 and B1, the ethyl acetate solution is obtained by mixing ethyl acetate and water in a 1:1 volume ratio.

[0013] Furthermore, in step A2, the column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate at a volume ratio of 5:1 as the eluent. In step B2, column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate at a volume ratio of 4-5:1 as the eluent. In step B3, column chromatography purification uses a mixed solution of dichloromethane and methanol at a volume ratio of 7-8:1 as the eluent.

[0014] Furthermore, when the selenoglycoside compound is any one of compounds 2a~2o and 2r~2t, the structural formula of the selenoglycoside donor used is shown in formula S6 below; ; When the selenoglycoside compound is compound 2p or 2q, the structural formula of the selenoglycoside donor used is shown in formula S9 below; .

[0015] Furthermore, when the selenoglycoside compound is compound 2a, the selenoglycoside acceptor used is phenylboronic acid; the structural formula is shown in formula 1a below. ; When the selenoglycoside compound is compound 2b, the selenoglycoside acceptor used is p-methoxyphenylboronic acid; the structural formula is shown in formula 1b below. ; When the selenoglycoside compound is compound 2c, the selenoglycoside acceptor used is p-chlorophenylboronic acid; the structural formula is shown in formula 1c below. ; When the selenoglycoside compound is compound 2d, the selenoglycoside acceptor used is m-bromophenylboronic acid; the structural formula is shown in formula 1d below. ; When the selenoglycoside compound is compound 2e, the selenoglycoside acceptor used is p-acetylphenylboronic acid; the structural formula is shown in formula 1e below; ; When the selenoglycoside compound is compound 2f, the selenoglycoside acceptor used is p-isopropylsulfonylphenylboronic acid; the structural formula is shown in formula 1f below; ; When the selenoglycoside compound is 2g, the selenoglycoside acceptor used is p-formylphenylboronic acid; the structural formula is shown in the following formula 1g; ; When the selenoglycoside compound is compound 2h, the selenoglycoside acceptor used is 2,4-dimethylphenylboronic acid; the structural formula is shown in formula 1h below; ; When the selenoglycoside compound is compound 2i, the selenoglycoside acceptor used is 2-chloro-4-methylphenylboronic acid; the structural formula is shown in formula 1i below; ; When the selenoglycoside compound is compound 2j, the selenoglycoside acceptor used is 2-methyl-4-methoxyphenylboronic acid; the structural formula is shown in formula 1j below; ; When the selenoglycoside compound is compound 2k, the selenoglycoside acceptor used is 2-methoxy-4-fluorophenylboronic acid; the structural formula is shown in formula 1k below; ; When the selenoglycoside compound is compound 2l, the selenoglycoside acceptor used is 9,9-dimethylfluorene-2-boronic acid; the structural formula is shown in Formula 1l below; ; When the selenoglycoside compound is compound 2m, the selenoglycoside acceptor used is 4-dibenzofuranboronic acid; the structural formula is shown in formula 1m below; ; When the selenoglycoside compound is compound 2n, the selenoglycoside acceptor used is phenoxathia-4-boronic acid; the structural formula is shown in formula 1n below; ; When the selenoglycoside compound is compound 2o, the selenoglycoside acceptor used is N -Boc-indole-2-boronic acid; structural formula shown in Formula 1o below; ; When the selenoglycoside compound is compound 2p, the selenoglycoside acceptor used is phenoxathia-4-boronic acid; the structural formula is shown in formula 1n below; ; When the selenoglycoside compound is compound 2q, the selenoglycoside acceptor used is 3-acetamidophenylboronic acid; the structural formula is shown in formula 1q below; ; When the selenoglycoside compound is compound 2r, the selenoglycoside acceptor used is 2-(4-methoxybenzyl)phenylboronic acid; the structural formula is shown in formula 1r below; ; When the selenoglycoside compound is compound 2s, the selenoglycoside acceptor used is 2-((2-(4-fluorophenyl)thiophen-5-yl)methyl)phenylboronic acid; the structural formula is shown in formula 1s below; ; When the selenoglycoside compound is compound 2t, the selenoglycoside acceptor used is 2-chloro-6-(4-(((S)-tetrahydrofuran-3-yl)oxy)benzyl)phenylboronic acid; the structural formula is shown in formula 1t below; .

[0016] Furthermore, the synthesis method of selenoglycoside donor S6 is as follows: C1: Selenium powder was dissolved in ethanol, and sodium borohydride was slowly added under an ice bath at 0°C until no more gas was produced in the system. 4-Methylbenzoyl chloride was added dropwise, and the mixture was stirred thoroughly for 30 min. Separately, elemental iodine and potassium iodide were dissolved in ethanol and added dropwise to the reaction system, and the mixture was stirred thoroughly for 30 min. The reaction was monitored by TLC until complete. The reaction was quenched with saturated sodium bicarbonate solution, diluted with dichloromethane, washed with water, evaporated to dryness, and then recrystallized from dichloromethane and petroleum ether. The mixture was filtered to obtain the intermediate compound S2. The molar ratio of 4-methylbenzoyl chloride, selenium powder, sodium borohydride, elemental iodine, and potassium iodide was 1:1:1.2:1:0.2. C2: Dissolve intermediate compound S2 in toluene, add 1M potassium hydroxide methanol solution, react at room temperature for 10 min, remove solvent by rotary evaporation, wash with petroleum ether, and filter to obtain intermediate compound S3; C3: The intermediate compound S3 and 2,3,4,6- O Acetyl-D-pyranose bromide was dissolved in ethyl acetate, and tetrabutylammonium bisulfate and sodium carbonate aqueous solution were added. The mixture was reacted at room temperature for three hours, and the reaction was monitored by TLC until complete. The solution was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography to give intermediate compound S4; wherein intermediate compounds S3, 2,3,4,6- O The molar ratio of acetyl-D-pyranose bromide to tetrabutylammonium hydrogen sulfate is 2:1:2; C4: Dissolve intermediate compound S4 in N,N-dimethylformamide, add piperazine, react at room temperature for 10 min, monitor the reaction for completeness by TLC, dilute with ethyl acetate, wash with 1M HCl solution and saturated brine, evaporate the solvent, and purify by column chromatography to obtain intermediate compound S5; wherein the molar ratio of intermediate compound S4 to piperazine is 1:1.25. C5: The intermediate compound S5 was dissolved in anhydrous acetonitrile, and sodium p-methylsulfinate and sulfoxide were added. The mixture was reacted at room temperature for 12 h. The reaction was monitored by TLC until it was complete. The reaction system was diluted with ethyl acetate, washed with water, and the solvent was evaporated. The target selenoglycoside donor S6 was purified by column chromatography. The molar ratio of intermediate compound S5, sodium p-methylsulfinate, and sulfoxide was 1:10:3.

[0017] Furthermore, the synthesis method of selenoglycoside donor S9 is as follows: D1: Selenium powder was dissolved in ethanol, and sodium borohydride was slowly added under an ice bath at 0°C until no more gas was produced in the system. 4-methylbenzoyl chloride was added dropwise, and the mixture was stirred thoroughly for 30 min. Separately, elemental iodine and potassium iodide were dissolved in ethanol and added dropwise to the reaction system, and the mixture was stirred thoroughly for 30 min. The reaction was monitored by TLC until complete. The reaction was quenched with saturated sodium bicarbonate solution, diluted with dichloromethane, washed with water, evaporated to dryness, and recrystallized from dichloromethane and petroleum ether. The mixture was then filtered to obtain the intermediate compound S2. The molar ratio of 4-methylbenzoyl chloride, selenium powder, sodium borohydride, elemental iodine, and potassium iodide was 1:1:1.2:1:0.2. D2: Dissolve intermediate compound S2 in toluene, add 1M potassium hydroxide methanol solution, react at room temperature for 10 min, remove solvent by rotary evaporation, wash with petroleum ether, and filter to obtain intermediate compound S3. D3: The intermediate compound S3 and 2,3,4,6- O Acetyl-D-pyranogalactose bromide was dissolved in ethyl acetate, and tetrabutylammonium bisulfate and sodium carbonate aqueous solution were added. The mixture was reacted at room temperature for three hours, and the reaction was monitored by TLC until complete. The solution was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography to give intermediate compound S7; wherein intermediate compounds S3, 2,3,4,6- O The molar ratio of acetyl-D-galactopyranose bromide to tetrabutylammonium hydrogen sulfate is 2:1:2; D4: Dissolve intermediate compound S7 in N,N-dimethylformamide, add piperazine, react at room temperature for 10 min, monitor the reaction for completeness by TLC, dilute with ethyl acetate, wash with 1M HCl solution and saturated brine, evaporate the solvent, and purify by column chromatography to obtain intermediate compound S8; wherein the molar ratio of intermediate compound S7 to piperazine is 1:1.25. D5: Dissolve intermediate compound S8 in anhydrous acetonitrile, add sodium p-methylsulfinate and sulfoxide, react at room temperature for 12 h, monitor the reaction for completeness by TLC, dilute the reaction system with ethyl acetate, wash with water, evaporate the solvent, and purify by column chromatography to obtain selenoglycoside donor S9; wherein the molar ratio of intermediate compound S8, sodium p-methylsulfinate and sulfoxide is 1:10:2.7.

[0018] The beneficial effects of this invention are as follows: This invention addresses a series of technical shortcomings in existing selenoglycoside synthesis technologies, such as high reagent toxicity, strong irritation, poor stability, harsh reaction conditions, cumbersome operation, insufficient stereoselectivity, poor substrate universality, and difficulty in achieving industrial application. It provides a green, efficient, and universally applicable method for synthesizing selenoglycoside compounds, which has significant beneficial technical effects.

[0019] The core reaction substrates used in this invention are glycosyl selenose sulfonate and (hetero)arylboronic acid. Both types of raw materials are readily available conventional reagents, with no irritating odor, excellent chemical stability and environmental tolerance. This avoids the use of highly toxic, highly irritating, and low-stability reagents such as diselenides, selenools, and glycosyl stananes in traditional synthesis processes, significantly reducing the safety management costs and waste treatment pressure of the synthesis process, and meeting the requirements of green chemistry development.

[0020] The synthesis method of this invention features mild reaction conditions, requiring only a catalytic amount of inexpensive silver nitrate as a catalyst. It enables the efficient conversion of selenoglycosides in a mixed solvent system of water and ethyl acetate at room temperature. The reaction system exhibits good compatibility with water, eliminating the need for strict anhydrous and oxygen-free operations and complex raw material pretreatment processes. This significantly simplifies the synthesis steps, reduces reaction energy consumption and production costs, and simultaneously demonstrates excellent product yield and extreme stereoselectivity. The α / β configuration ratio of the obtained target selenoglycoside product is less than 1:30, allowing for high selectivity in obtaining the target product with a single configuration. This greatly reduces the difficulty of subsequent product separation and purification processes and possesses excellent adaptability for continuous industrial production. Furthermore, this method exhibits excellent substrate compatibility and functional group tolerance to various substituted arylboronic acids and heteroarylboronic acids, and can efficiently convert a series of structurally diverse heteroarylboronic acids into corresponding selenoglycoside products. It can rapidly construct a library of heteroaryl selenoglycoside compounds with rich structures and diverse functional groups, providing an efficient and universal synthetic tool for the activity screening of selenoglycoside drug molecules and the design and development of glycosyl bioprobes. It has broad application prospects and industrialization value in the fields of pharmaceutical research and development, biochemical engineering, and basic research in glycochemistry. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the synthetic route of the selenoglycoside compound in Example 1; Figure 2 This is a schematic diagram of the synthetic route for selenoglycoside donor S6 in Example 2; Figure 3 This is a schematic diagram of the synthetic route for the selenoglycoside donor S9 in Example 3. Detailed Implementation

[0022] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0023] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available analytical grade materials.

[0024] Example 1 Synthesis of selenoglycoside compounds Adopting such Figure 1 The synthetic route shown below synthesizes the selenoglycoside compound represented by Formula I;

[0025] I Wherein, R1 is Ac or H; R2 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

[0026] Selenoglycosides include the following compounds:

[0027]

[0028] The specific steps for preparing any one of compounds 2a to 2q are as follows: A1: Dissolve selenoglycoside donor, selenoglycoside acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; A2: After the reaction is complete, dilute with ethyl acetate, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate the solvent, and finally purify by column chromatography to obtain any one of the selenoglycoside compounds 2a~2q. The following specific steps are used to prepare any one of compounds 2r to 2t: B1: Dissolve selenoglycosylate donor, selenoglycosylate acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; B2: After the reaction was completed, the mixture was diluted with ethyl acetate, washed with water, dried with anhydrous sodium sulfate, the solvent was evaporated, and finally purified by column chromatography to obtain the selenoglycoside intermediate. B3: Dissolve the selenoglycoside intermediate in methanol, add sodium methoxide, react at room temperature for 1 hour, add acidic resin to adjust the pH to 7-8, filter, evaporate the solvent, and purify by column chromatography to obtain any one of the selenoglycoside compounds 2r-2t.

[0029] Selenium glycosyl donor The compound S6 is shown in formula S6 below or the compound S9 is shown in formula S9 below; ; ; To investigate the effects of the type of silver salt catalyst and the type of base additive on the synthesis process, the synthesis of compound 2a was used as an example. The experimental setup included compound S6 (0.1 mmol, 1 equiv.), selenoglycosylated acceptor 1a (0.12 mmol, 1.2 equiv.), silver salt catalyst (10 mol%), base additive (0.15 mmol, 1.5 equiv.), and ethyl acetate solvent (1.0 mL). Except for the types of catalyst and base additive, all other experimental conditions were kept consistent. Dibromomethane was used as an internal standard. 1 1H NMR analysis was used to determine the yield of compound 2a. The results are shown in Table 1. Table 1

[0030] As shown in Table 1, when the silver salt catalyst is silver nitrate (AgNO3) and the base additive is N,N-diisopropylethylamine (DIPEA), the yield of compound 2a can exceed 50%, which is significantly higher than the other combinations.

[0031] Furthermore, to investigate the effect of solvent on the synthesis process, the synthesis of compound 2a was used as an example. DIPEA was selected as the base additive, AgNO3 as the silver salt catalyst, and different solvents were used for synthesis. The following were used: compound S6 (0.1 mmol, 1 equiv.), selenoglycosylated acceptor 1a (0.12 mmol, 1.2 equiv.), AgNO3 (10 mol%), DIPEA (0.2 mmol, 2 equiv.), and solvent (1.0 mL). Except for the type of solvent, all other experimental conditions were the same. Dibromomethane was used as an internal standard. 1 1H NMR analysis was used to determine the yield of compound 2a. The results are shown in Table 2. Table 2

[0032] As shown in Table 2, when using the method of the present invention, the yield of compound 2a is the highest when using an ethyl acetate solution with a volume ratio of ethyl acetate to water of 1:1 as the solvent.

[0033] Example 2 Synthesis of selenoglycoside donor S6 Adopting such Figure 2 The roadmap shown illustrates the synthesis of the selenoglycosylate donor S6, with the following specific steps: (1) Selenium powder (4g, 50.66mmol) was dissolved in ethanol (50mL), and sodium borohydride (2.5g, 66.09mmol, 1.2equiv) was slowly added under an ice bath at 0℃ until no more gas was produced in the system. 4-methylbenzoyl chloride, i.e., compound S1 (5.6mL, 50.66mmol, 1equiv), was added dropwise and stirred thoroughly for 30min. Iodine (6.25g, 50.66mmol, 1equiv) and potassium iodide (1.65g, 9.94mmol, 0.2equiv) were dissolved in ethanol (15mL) and added dropwise to the reaction system and stirred thoroughly for 30min. The reaction was monitored by TLC until it was complete. The reaction was quenched with saturated sodium bicarbonate solution. The system was diluted with dichloromethane, washed with water, dried by rotary evaporation, and recrystallized with dichloromethane and petroleum ether. The mixture was filtered to obtain white crystals, i.e., intermediate compound S2.

[0034] (2) Dissolve intermediate compound S2 in toluene (30 mL), add 1 M potassium hydroxide methanol solution (15 mL), react at room temperature for 10 min, remove solvent by rotary evaporation, wash with petroleum ether, and filter to obtain green precipitate, which is intermediate compound S3.

[0035] (3) The intermediate compound S3 (2.37 g, 10 mmol, 2 equiv) and 2,3,4,6- O Acetyl-D-pyranose bromide (2.06 g, 5 mmol) was dissolved in ethyl acetate (50 mL), and tetrabutylammonium bisulfate (3.4 g, 10 mmol, 2 equiv) and sodium carbonate aqueous solution (2.33 g dissolved in 22 mL) were added. The reaction was carried out at room temperature for three hours. The reaction was monitored by TLC until it was complete. The reaction system was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography (PE:EA = 3:1) to give a white solid, namely intermediate compound S4 (2.14 g, 81%).

[0036] (4) Dissolve intermediate compound S4 (2g, 3.8mmol) in N,N-dimethylformamide (40mL), add piperazine (0.4g, 4.8mmol, 1.25equiv), react at room temperature for 10min, monitor the reaction to ensure completeness by TLC, dilute the reaction with ethyl acetate, wash with 1M HCl solution, saturated sodium bicarbonate and saturated brine, evaporate the solvent, and purify by column chromatography (PE:EA=1:1) to obtain a yellow viscous liquid, which is intermediate compound S5 (2.24g, 72%).

[0037] (5) Compound S5 (2.05 g, 2.5 mmol) was dissolved in anhydrous acetonitrile (50 mL), and sodium p-methanesulfonate (4.46 g, 25 mmol, 10 equiv) and sulfoxide (0.46 mL, 7.5 mmol, 3 equiv) were added. The reaction was carried out at room temperature for 12 h. The reaction was monitored by TLC until complete. The reaction system was diluted with ethyl acetate, washed with water, and the solvent was evaporated. The solution was purified by column chromatography (PE:EA = 2:1) to obtain selenoglycosylation donor S6 (760 mg, 54%). Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.79 (d, J = 8.2 Hz, 2H), 7.32 (d, J = 8.1 Hz, 2H), 5.54 (d, J = 10.5 Hz, 1H), 5.29 (s, 1H), 5.15 –5.03 (m, 2H), 4.17 (dd, J = 12.5, 4.5 Hz, 1H), 4.02 (dd, J = 12.6, 2.3 Hz, 1H),3.82 – 3.73 (m, 1H), 2.44 (s, 3H), 2.06 (s, 3H), 2.03 (s, 3H), 2.00 (d, J =2.0 Hz, 6H).

[0038] Example 3 Synthesis of selenoglycoside donor S9 Intermediate compound S3 was prepared using the method of Example 1, and then... Figure 3 The roadmap shown illustrates the synthesis of the selenoglycosylate donor S9, with the following specific steps: (1) The intermediate compound S3 (1.15 g, 4.86 mmol, 2 equiv) and 2,3,4,6-O-acetyl-D-pyranogalactose bromide (1 g, 2.43 mmol, 1 equiv) were dissolved in ethyl acetate (20 mL), and tetrabutylammonium bisulfate (1.65 g, 4.86 mmol, 2 equiv) and sodium carbonate aqueous solution (567 mg dissolved in 5.35 mL) were added. The reaction was carried out at room temperature for three hours. The reaction was monitored by TLC until it was complete. The reaction system was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography (PE:EA = 3:1) to obtain a white solid, namely the intermediate compound S7 (991 mg, 77%).

[0039] (2) The intermediate compound S7 (991 mg, 1.9 mmol) was dissolved in N,N-dimethylformamide (15 mL), and piperazine (201.6 mg, 2.34 mmol, 1.25 equiv) was added. The reaction was carried out at room temperature for 20 min. The reaction was monitored by TLC until it was complete. The reaction was diluted with ethyl acetate, washed with 1 M HCl solution, saturated sodium bicarbonate and saturated saline, the solvent was evaporated, and the solution was purified by column chromatography (PE:EA=1:1) to obtain a yellow viscous liquid, which is the intermediate compound S8 (558 mg, 81%).

[0040] (3) Compound S8 (558 mg, 0.84 mmol) was dissolved in anhydrous acetonitrile (15 mL), and sodium p-methanesulfonate (1.5 g, 8.4 mmol, 10 equiv) and sulfoxide (0.14 mL, 2.3 mmol, 2.7 equiv) were added. The reaction was carried out at room temperature for 12 h. The reaction was monitored by TLC until complete. The reaction system was diluted with ethyl acetate, washed with water, and the solvent was evaporated. The solution was purified by column chromatography (PE:EA = 2:1) to obtain selenoglycosylation donor S9 (311 mg, 65%). Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.79 (d, J = 8.1 Hz, 2H), 7.33 (d, J = 8.0 Hz, 2H), 5.56 (d, J = 10.4 Hz, 1H), 5.46 (d, J = 3.3 Hz, 1H), 5.27 (t, J = 10.1 Hz, 1H), 5.12 (dd, J = 9.9, 3.4 Hz, 1H), 4.08 – 3.89 (m,3H), 2.45 (s, 2H), 2.11 (s, 3H), 2.06 (s, 3H), 2.02 (s, 3H), 1.98 (s, 3H), 1.61 (s, 1H).

[0041] Example 4 Synthesis of selenoglycoside compound 2a The selenoglycoside compound 2a was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), phenylboronic acid 1a (14.6 mg, 0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2a as a white solid (42.3 mg, 87%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ 7.64 – 7.57 (m, 2H), 7.35 (t, J = 7.1 Hz, 1H), 7.30 (dd, J =8.1, 6.5 Hz, 2H), 5.19 (t, J = 9.3 Hz, 1H), 5.01 (q, J = 9.8 Hz, 2H), 4.88(d, J = 10.2 Hz, 1H), 4.19 (t, J = 3.3 Hz, 2H), 3.69 (ddd, J = 10.1, 4.6, 2.9Hz, 1H), 2.07 (d, J = 1.2 Hz, 6H), 2.01 (s, 3H), 1.98 (s, 3H). Example 5 Synthesis of selenoglycoside compound 2b The selenoglycoside compound 2b was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), p-methoxyphenylboronic acid 1b (18.2 mg, 0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2b as a white solid (42.5 mg, 80%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1H NMR (400 MHz, CDCl3) δ 7.59 – 7.43 (m, 2H), 6.88 – 6.77 (m, 2H), 5.16 (t, J = 9.4 Hz, 1H), 4.95 (dt, J = 22.9, 9.6 Hz, 2H), 4.76 (d, J = 10.1 Hz, 1H), 4.17 (d, J = 3.6 Hz, 2H), 3.81 (s, 3H), 3.65 (dt, J = 10.2, 3.6 Hz, 1H), 2.08 (s, 3H), 2.06 (s, 3H), 2.00 (s, 3H), 1.97 (s, 3H). Example 6 Synthesis of selenoglycoside compound 2c The selenoglycoside compound 2c was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (0.1 mmol), p-chlorophenylboronic acid 1c (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2c as a white solid (43.3 mg, 83%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3)δ 7.59 – 7.49 (m, 2H), 7.27 (d, J = 2.0 Hz, 1H), 7.25 (s, 1H), 5.18 (t, J = 9.3Hz, 1H), 4.97 (dt, J = 18.8, 9.6 Hz, 2H), 4.83 (d, J = 10.1 Hz, 1H), 4.17 (d, J = 3.5 Hz, 2H), 3.68 (dt, J= 10.1, 3.7 Hz, 1H), 2.07 (d, J = 1.9 Hz, 6H), 1.99(d, J = 11.3 Hz, 6H). Example 7 Synthesis of selenoglycoside compound 2d The selenoglycoside compound 2d was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), m-bromophenylboronic acid 1d (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2d as a white solid (43.0 mg, 85%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3)δ 7.77 (t, J = 1.8 Hz, 1H), 7.58 – 7.44 (m, 2H), 7.17 (t, J = 7.9 Hz, 1H), 5.20(t, J = 9.3 Hz, 1H), 5.01 (dt, J = 17.1, 9.6 Hz, 2H), 4.89 (d, J = 10.1 Hz, 1H), 4.19 (qd, J = 12.4, 3.7 Hz, 2H), 3.71 (ddd, J = 10.1, 4.9, 2.3 Hz, 1H), 2.10(s, 3H), 2.07 (s, 3H), 2.01 (s, 3H), 1.99 (s, 3H). Example 8 Synthesis of selenoglycoside compound 2e The selenoglycoside compound 2e was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), p-acetylphenylboronic acid 1e (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2e as a white solid (46.6 mg, 88%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3)δ 7.85 (d, J = 8.1 Hz, 2H), 7.67 (d, J = 8.3 Hz, 2H), 5.21 (t, J =9.1 Hz, 1H), 5.09 – 4.93 (m, 3H), 4.29 – 4.13 (m, 2H), 3.74 (ddd, J = 10.0,4.9, 2.5 Hz, 1H), 2.60 (s, 3H), 2.08 (s, 3H), 2.06 (s, 3H), 2.02 (s, 3H),1.98 (s, 3H). Example 9 Synthesis of selenoglycoside compound 2f The selenoglycoside compound 2f was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), p-isopropylsulfonylphenylboronic acid 1f (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2f as a white solid (54.6 mg, 92%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1H NMR (400 MHz, CDCl3) δ 7.75 (d, J = 1.6 Hz, 4H), 5.21 (t, J = 8.9 Hz, 1H), 5.10 –4.97 (m, 3H), 4.19 (qd, J = 12.5, 3.9 Hz, 2H), 3.75 (ddd, J = 10.6, 5.1, 2.6Hz, 1H), 3.19 (p, J = 6.4 Hz, 1H), 2.07 (d, J = 1.6 Hz, 3H), 2.05 (s, 3H), 2.01(s, 3H), 1.98 (s, 3H), 1.29 (dd, J = 6.9, 1.6 Hz, 6H). Example 10 Synthesis of 2g of selenoglycoside compound The synthesis of 2g of selenoglycoside compound was carried out using selenoglycoside donor S6, which was prepared according to the method in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), p-formylphenylboronic acid 1 g (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give 2 g of the compound as a white solid (45.6 mg, 88%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ 9.99 (s, 1H), 7.78 (d, J = 8.1 Hz, 2H), 7.73 (d, J = 8.1 Hz, 2H), 5.22 (t, J = 8.9 Hz, 1H), 5.11 – 4.96 (m, 3H), 4.28 – 4.14 (m, 2H), 3.76 (ddd, J= 10.1, 5.1, 2.6 Hz, 1H), 2.08 (s, 3H), 2.06 (s, 3H), 2.02 (s, 3H), 1.99(s, 3H). Example 11 Synthesis of selenoglycoside compound 2h The selenoglycoside compound 2h was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 2,4-dimethylphenylboronic acid 1h (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give the compound as a white solid (46.4 mg, 90%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ 7.50 (d, J = 7.8 Hz, 1H), 7.06 (d, J = 2.1 Hz, 1H), 6.92 (dd, J =7.8, 2.0 Hz, 1H), 5.17 (t, J = 9.3 Hz, 1H), 5.04 (td, J = 9.6, 1.7 Hz, 2H), 4.82 (d, J = 10.1 Hz, 1H), 4.15 (qd, J = 12.3, 3.9 Hz, 2H), 3.64 (ddd, J = 10.1,5.3, 2.5 Hz, 1H), 2.39 (s, 3H), 2.31 (s, 3H), 2.07 (d, J = 1.8 Hz, 6H), 2.01(s, 3H), 1.99 (s, 3H). Example 12 Synthesis of selenoglycoside compound 2i The selenoglycoside compound 2i was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 2-chloro-4-methylphenylboronic acid 1i (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2i as a white solid (50.9 mg, 95%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.52 (d, J = 7.9 Hz, 1H), 7.26 – 7.21 (m, 1H), 7.03 – 6.95(m, 1H), 5.21 (t, J = 9.2 Hz, 1H), 5.07 (td, J = 9.6, 3.2 Hz, 2H), 4.97 (d, J =10.2 Hz, 1H), 4.22 (dd, J = 12.3, 5.3 Hz, 1H), 4.13 (dd, J = 12.4, 2.4 Hz, 1H),3.71 (ddd, J = 10.2, 5.3, 2.4 Hz, 1H), 2.32 (s, 3H), 2.07 (s, 3H), 2.05 (s, 3H), 2.02 (s, 3H), 1.99 (s, 3H). Example 13 Synthesis of selenoglycoside compound 2j The selenoglycoside compound 2j was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 2-methyl-4-methoxyphenylboronic acid 1j (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2j as a white solid (49.9 mg, 94%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.55 (d, J = 8.6 Hz, 1H), 6.79 (d, J = 2.8 Hz, 1H), 6.66(dd, J = 8.5, 2.9 Hz, 1H), 5.16 (t, J = 9.3 Hz, 1H), 5.01 (q, J = 9.8 Hz, 2H), 4.74 (d, J = 10.2 Hz, 1H), 4.14 (qd, J = 12.3, 3.8 Hz, 2H), 3.79 (s, 3H), 3.61(ddd, J = 9.7, 5.0, 2.5 Hz, 1H), 2.43 (s, 3H), 2.08 (s, 3H), 2.06 (s, 3H), 2.00 (s, 3H), 1.98 (s, 3H). Example 14 Synthesis of selenoglycoside compound 2k The selenoglycoside compound 2k was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 2-methoxy-4-fluorophenylboronic acid 1k (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2k as a white solid (46.8 mg, 87%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.50 (t, J = 7.4 Hz, 1H), 6.68 – 6.54 (m, 2H), 5.18 (t, J =9.1 Hz, 1H), 5.10 – 4.87 (m, 3H), 4.15 (qd, J = 12.3, 3.7 Hz, 2H), 3.82 (s,3H), 3.69 (ddd, J = 10.1, 5.1, 2.5 Hz, 1H), 2.05 (s, 3H), 2.03 (s, 3H), 2.01(s, 3H), 1.98 (s, 3H). Example 15 Synthesis of selenoglycoside compound 2l The selenoglycoside compound 2l was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 9,9-dimethylfluorene-2-boronic acid 1 L (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2 L as a white solid (50.2 mg, 80%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1H NMR (400 MHz, CDCl3) δ 7.71 (dd, J = 5.9, 2.8 Hz, 1H), 7.68 – 7.62 (m, 2H), 7.58(dd, J = 7.8, 1.5 Hz, 1H), 7.44 (dd, J = 5.9, 2.8 Hz, 1H), 7.38 – 7.31 (m, 2H), 5.20 (t, J = 9.3 Hz, 1H), 5.03 (td, J = 9.5, 6.8 Hz, 2H), 4.91 (d, J = 10.1 Hz, 1H), 4.26 (dd, J = 12.4, 4.9 Hz, 1H), 4.15 (dd, J = 12.4, 2.3 Hz, 1H), 3.70(ddd, J = 10.2, 4.9, 2.3 Hz, 1H), 2.10 (s, 3H), 2.08 (s, 3H), 2.00 (s, 3H),1.98 (s, 3H), 1.49 (d, J = 2.1 Hz, 6H). Example 16 Synthesis of selenoglycoside compound 2m The selenoglycoside compound 2m was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), 4-dibenzofuranboronic acid 1m (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2m as a white solid (55.5 mg, 96%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 7.99 – 7.92 (m, 2H), 7.70 (dd, J= 7.6, 1.2 Hz, 1H), 7.61(d, J = 8.2 Hz, 1H), 7.52 – 7.45 (m, 1H), 7.34 (dt, J = 21.7, 7.6 Hz, 2H), 5.24– 5.11 (m, 2H), 5.09 – 4.98 (m, 2H), 4.12 (qd, J = 12.3, 3.6 Hz, 2H), 3.68(ddd, J = 10.1, 4.8, 2.3 Hz, 1H), 2.06 (s, 3H), 1.97 (d, J = 10.1 Hz, 6H), 1.83 (s, 3H). Example 17 Synthesis of selenoglycoside compound 2n The selenoglycoside compound 2n was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S6 (56.5 mg, 0.1 mmol), phenoxathia-4-boronic acid 1n (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2n as a white solid (58.2 mg, 95%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ 7.34 (dd, J = 7.7, 1.5 Hz, 1H), 7.18 – 7.10 (m, 2H), 7.09 – 7.00(m, 3H), 6.95 (t, J = 7.7 Hz, 1H), 5.30 – 5.07 (m, 4H), 4.19 (dd, J = 12.3, 5.4Hz, 1H), 4.08 (dd, J = 12.3, 2.3 Hz, 1H), 3.73 (ddd, J= 10.1, 5.5, 2.3 Hz,1H), 2.05 (s, 3H), 2.04 (s, 3H), 2.02 (s, 3H), 2.00 (s, 3H). Example 18 Synthesis of selenoglycoside compound 2o The selenoglycoside compound 2o was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenyl glycosyl donor S6 (56.5 mg, 0.1 mmol), N -Boc-indole-2-boronic acid 1o (0.12 mmol, 1.2 equiv.) and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2o as a white solid (61.1 mg, 97%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3) δ 8.05 – 7.95 (m, 1H), 7.46 – 7.38 (m, 1H), 7.20 (td, J =6.6, 3.9 Hz, 2H), 6.60 (s, 1H), 5.36 – 5.19 (m, 2H), 5.13 (t, J = 9.6 Hz, 2H), 4.21 (qd, J = 12.3, 4.3 Hz, 2H), 3.87 (ddd, J = 10.2, 6.1, 2.4 Hz, 1H), 2.08(s, 3H), 2.05 (d, J = 6.0 Hz, 6H), 2.02 (s, 3H), 1.68 (s, 9H). Example 19 Synthesis of selenoglycoside compound 2p The selenoglycoside compound 2p was synthesized using selenoglycoside donor S9, which was prepared according to the method described in Example 3; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S9 (0.1 mmol), phenoxathia-4-boronic acid 1n (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2p as a white solid (58.8 mg, 96%) with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CDCl3)δ 7.38 (dd, J = 7.7, 1.5 Hz, 1H), 7.19 – 7.00 (m, 5H), 6.95 (t, J = 7.7 Hz, 1H), 5.45 (d, J = 3.3 Hz, 1H), 5.41 (t, J = 10.1 Hz, 1H), 5.12 – 5.03 (m, 2H), 4.11 (qd, J = 11.4, 6.5 Hz, 2H), 3.94 (t, J = 6.6 Hz, 1H), 2.16 (s, 3H), 2.06 (s, 3H), 2.01 (s, 3H), 1.98 (s, 3H). Example 20 Synthesis of selenoglycoside compound 2q The selenoglycoside compound 2q was synthesized using selenoglycoside donor S9, which was prepared according to the method described in Example 3; the synthetic reaction formula is shown below. ; Selenose glycosyl donor S9 (0.1 mmol), 3-acetamidophenylboronic acid 1q (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to give compound 2q as a white solid (47.3 mg, 87%) with an α / β ratio less than 1:30. Its NMR data are as follows:1 H NMR (400 MHz, CDCl3)δ7.64 (d, J = 15.9 Hz, 3H), 7.33 (d, J = 7.7 Hz, 1H), 7.23 (d, J = 7.7 Hz, 1H), 5.40 (d, J = 3.3 Hz, 1H), 5.23 (t, J = 10.0 Hz, 1H), 5.01 (dd, J = 9.9, 3.3 Hz, 1H), 4.91 (d, J = 10.1 Hz, 1H), 4.30 (dd, J = 11.4, 6.6 Hz, 1H), 4.02 (dd, J =11.4, 6.1 Hz, 1H), 3.92 (t, J = 6.4 Hz, 1H), 2.18 (s, 3H), 2.08 (s, 3H), 2.07(s, 3H), 2.06 (s, 3H), 1.96 (s, 3H). Example 21 Synthesis of selenoglycoside compound 2r The selenoglycoside compound 2r was synthesized using selenoglycoside donor S6, which was prepared as described in Example 2; the synthetic reaction formula is shown below. ; Selenoglycoside donor S6 (0.1 mmol), 2-(4-methoxybenzyl)phenylboronic acid 1r (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 4:1) to obtain selenoglycoside S10. Next, selenoglycoside S10 was dissolved in methanol (1 mL), and sodium methoxide (0.54 mg, 0.01 mmol, 0.1 equiv.) was added. The reaction was carried out at room temperature for 1 h. The reaction solution was adjusted to pH 7-8 with acidic resin, filtered, the solvent was evaporated, and purified by column chromatography (DCM:MeOH = 7:1) to obtain compound 2r as a white solid (36.9 mg, 84% for 2 steps), with an α / β ratio less than 1:30. Its NMR data are as follows:1 H NMR (400 MHz, CD3OD) δ 7.75 (d, J = 7.6 Hz, 1H), 7.20 –7.15 (m, 1H), 7.11 (d, J = 7.4 Hz, 2H), 7.00 (d, J = 8.2 Hz, 2H), 6.75 (d, J =8.6 Hz, 2H), 4.78 (d, J = 9.5 Hz, 1H), 4.09 (s, 2H), 3.80 (dd, J = 12.1, 2.2Hz, 1H), 3.70 (s, 3H), 3.62 (dd, J = 12.0, 5.3 Hz, 1H), 3.29 – 3.26 (m, 3H), 3.25 – 3.19 (m, 1H). Example 22 Synthesis of selenoglycoside compound 2S The selenoglycoside compound 2s was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula for 2s is shown below. ; Selenose glycoside donor S6 (0.1 mmol), 2-((2-(4-fluorophenyl)thiophen-5-yl)methyl)phenylboronic acid 1s (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to obtain selenoglycoside S11. Next, selenoglycoside S11 was dissolved in methanol (1 mL), and sodium methoxide (0.54 mg, 0.01 mmol, 0.1 equiv.) was added. The reaction was carried out at room temperature for 1 h. The reaction solution was adjusted to pH 7-8 with the addition of acidic resin, filtered, the solvent was evaporated, and purified by column chromatography (DCM:MeOH = 8:1) to give compound 2s as a white solid (45.5 mg, 87% for 2 steps), with an α / β ratio less than 1:30. Its NMR data are as follows: 1 H NMR (400 MHz, CD3OD) δ 7.70 (d, J=6.1 Hz, 1H), 7.46 (q, J = 2.8 Hz, 2H), 7.13 – 7.05 (m, 2H), 6.99 (d, J = 8.5Hz, 3H), 6.54 (d, J = 3.8 Hz, 1H), 4.77 (d, J = 9.5 Hz, 1H), 4.54 – 4.42 (m,2H), 3.78 (dd, J = 12.1, 2.3 Hz, 1H), 3.61 (dd, J = 12.1, 5.4 Hz, 1H), 3.33 (d, J = 8.5 Hz, 1H), 3.29 – 3.25 (m, 2H), 3.20 (ddd, J = 11.4, 6.0, 3.3 Hz, 1H), 2.30 (s, 3H). Example 23 Synthesis of selenoglycoside compound 2t The selenoglycoside compound 2t was synthesized using selenoglycoside donor S6, which was prepared according to the method described in Example 2; the synthetic reaction formula for 2t is shown below. ; Selenoglycoside donor S6 (0.1 mmol), 2-chloro-6-(4-(((S)-tetrahydrofuran-3-yl)oxy)benzyl)phenylboronic acid 1t (0.12 mmol, 1.2 equiv.), and AgNO3 (1.68 mg, 10 mol%) were dissolved in a 1:1 mixture of ethyl acetate and water (1 mL). DIPEA (36 μL, 0.2 mmol, 2 equiv.) was added, and the reaction was carried out at room temperature for 12–24 h. The reaction was monitored by TLC until complete. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous Na2SO4, and the solvent was evaporated. The mixture was then purified by column chromatography (PE:ethyl acetate = 5:1) to obtain selenoglycoside S12. Next, selenoglycoside S12 was dissolved in methanol (1 mL), and sodium methoxide (0.54 mg, 0.01 mmol, 0.1 equiv.) was added. The reaction was carried out at room temperature for 1 h. The reaction solution was adjusted to pH 7-8 with the addition of acidic resin, filtered, the solvent was evaporated, and purified by column chromatography (DCM:MeOH = 8:1) to obtain compound 2t as a white solid (42.9 mg, 81% for 2 steps), with an α / β ratio less than 1:30. Its NMR data are as follows: 1H NMR (400 MHz, CD3OD) δ 7.78 – 7.72(m, 1H), 7.34 – 7.28 (m, 1H), 7.13 (t, J = 7.9 Hz, 1H), 6.95 (d, J = 8.3 Hz, 2H), 6.71 (d, J = 8.6 Hz, 2H), 4.82 (d, J = 9.4 Hz, 1H), 4.38 – 4.27 (m, 2H), 3.86 (ddd, J = 13.3, 7.6, 3.1 Hz, 3H), 3.80 (dt, J = 10.6, 3.2 Hz, 2H), 3.61(dd, J = 12.1, 5.4 Hz, 1H), 3.33 (d, J = 8.3 Hz, 1H), 3.30 (s, 1H), 3.29 – 3.25(m, 2H), 3.24 – 3.20 (m, 1H), 2.14 (dtd, J = 14.2, 8.4, 5.9 Hz, 1H), 2.05 –1.97 (m, 1H). Dapagliflozin, empagliflozin, canagliflozin, and other selenogliflozin-like drugs are important oral hypoglycemic agents. These drugs belong to the sodium-glucose cotransporter 2 inhibitor class (SGLT-2i). They exert their hypoglycemic effect by inhibiting SGLT-2 expression in the proximal renal tubules, reducing renal glucose reabsorption, and promoting urinary glucose excretion. In addition, selenogliflozin-like drugs have good protective effects on the kidneys and heart while lowering blood sugar. The selenogliflozin glycoside 2r-2t is a bioisosteric compound of selenogliflozin-like drugs such as dapagliflozin, canagliflozin, and empagliflozin. In vitro glucose uptake experiments (monitoring the uptake of the fluorescently modified glucose analog 2-NBDG in HEK293 cells) showed that the selenogliflozin glycoside 2r-2t has good SGLT-2 inhibitory activity, with an IC50 value of [missing information]. 50 The values ​​were at 89 nM, 43 nM, and 29 nM, respectively.

Claims

1. A selenium glycoside compound, characterized in that, The structural formula is shown in Equation I below; I Wherein, R1 is Ac or H; R2 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

2. The selenoglycoside compound according to claim 1, characterized in that, The selenoglycoside compound is any one of the following compounds; In compound 2a, R1 is Ac and R2 is phenyl; in compound 2b, R1 is Ac and R2 is 4-methoxyphenyl; in compound 2c, R1 is Ac and R2 is 4-chlorophenyl; in compound 2d, R1 is Ac and R2 is 3-bromophenyl; in compound 2e, R1 is Ac and R2 is 4-acetylphenyl; in compound 2f, R1 is Ac and R2 is 4-isopropylsulfonylphenyl; in compound 2g, R1 is Ac and R2 is 4-formylphenyl; and in compound 2h, R1 is Ac and R2 is 2,4- Dimethylphenyl; in compound 2i, R1 is Ac and R2 is 2-chloro-4-methylphenyl; in compound 2j, R1 is Ac and R2 is 2-methyl-4-methoxyphenyl; in compound 2k, R1 is Ac and R2 is 2-methoxy-4-fluorophenyl; in compound 2l, R1 is Ac and R2 is 9,9-dimethylfluorene-2-yl; in compound 2m, R1 is Ac and R2 is dibenzofuran-4-yl; in compound 2n, R1 is Ac and R2 is phenoxazine-4-yl; in compound 2o, R1 is Ac and R2 is... N -Boc-indol-2-yl; R1 of compound 2p is Ac, and R2 is phenoxathio-4-yl; R1 of compound 2q is Ac, and R2 is 3-acetamidophenyl; R1 of compound 2r is H, and R2 is 2-(4-methoxybenzyl)phenyl; H of compound 2s is Ac, and R2 is 2-((2-(4-fluorophenyl)thiophen-5-yl)methyl)phenyl; R1 of compound 2t is H, and R2 is 2-chloro-6-(4-(((S)-tetrahydrofuran-3-yl)oxy)benzyl)phenyl.

3. A method for synthesizing the selenoglycoside compound according to claim 2, characterized in that, The following specific steps are used to prepare any one of compounds 2a to 2q: A1: Dissolve selenoglycoside donor, selenoglycoside acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; A2: After the reaction is complete, dilute with ethyl acetate, wash with water, dry the organic phase with anhydrous sodium sulfate, evaporate the solvent, and finally purify by column chromatography to obtain any one of the selenoglycoside compounds 2a~2q. The following specific steps are used to prepare any one of compounds 2r to 2t: B1: Dissolve selenoglycosylate donor, selenoglycosylate acceptor and silver nitrate in ethyl acetate solution, then add N,N-diisopropylethylamine, stir well and react at room temperature for 12~24h; B2: After the reaction was completed, the mixture was diluted with ethyl acetate, washed with water, dried with anhydrous sodium sulfate, the solvent was evaporated, and finally purified by column chromatography to obtain the selenoglycoside intermediate. B3: Dissolve the selenoglycoside intermediate in methanol, add sodium methoxide, react at room temperature for 1 hour, add acidic resin to adjust the pH to 7-8, filter, evaporate the solvent, and purify by column chromatography to obtain any one of the selenoglycoside compounds 2r-2t.

4. The synthesis method according to claim 3, characterized in that, In steps A1 and B1, the molar ratio of selenoglycosylate donor, selenoglycosylate acceptor, silver nitrate and N,N-diisopropylethylamine is 1:1.2:0.1:

2.

5. The synthesis method according to claim 4, characterized in that, In steps A1 and B1, the ethyl acetate solution was obtained by mixing ethyl acetate and water in a volume ratio of 1:

1.

6. The synthesis method according to claim 3, characterized in that, In step A2, column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate at a volume ratio of 5:1 as the eluent. In step B2, column chromatography purification uses a mixed solution of petroleum ether and ethyl acetate at a volume ratio of 4-5:1 as the eluent. In step B3, column chromatography purification uses a mixed solution of dichloromethane and methanol at a volume ratio of 7-8:1 as the eluent.

7. The synthesis method according to claim 3, characterized in that, When the selenoglycoside compound is any one of compounds 2a~2o and 2r~2t, the structural formula of the selenoglycoside donor used is shown in formula S6 below; ； When the selenoglycoside compound is compound 2p or 2q, the structural formula of the selenoglycoside donor used is shown in formula S9 below; 。 8. The synthesis method according to claim 7, characterized in that, When the selenoglycoside compound is compound 2a, the selenoglycoside acceptor used is phenylboronic acid; the structural formula is shown in formula 1a below. ； When the selenoglycoside compound is compound 2b, the selenoglycoside acceptor used is p-methoxyphenylboronic acid; the structural formula is shown in formula 1b below. ； When the selenoglycoside compound is compound 2c, the selenoglycoside acceptor used is p-chlorophenylboronic acid; the structural formula is shown in formula 1c below. ； When the selenoglycoside compound is compound 2d, the selenoglycoside acceptor used is m-bromophenylboronic acid; the structural formula is shown in formula 1d below. ； When the selenoglycoside compound is compound 2e, the selenoglycoside acceptor used is p-acetylphenylboronic acid; the structural formula is shown in formula 1e below; ； When the selenoglycoside compound is compound 2f, the selenoglycoside acceptor used is p-isopropylsulfonylphenylboronic acid; the structural formula is shown in formula 1f below; ； When the selenoglycoside compound is 2g, the selenoglycoside acceptor used is p-formylphenylboronic acid; the structural formula is shown in the following formula 1g; ； When the selenoglycoside compound is compound 2h, the selenoglycoside acceptor used is 2,4-dimethylphenylboronic acid; the structural formula is shown in formula 1h below; ； When the selenoglycoside compound is compound 2i, the selenoglycoside acceptor used is 2-chloro-4-methylphenylboronic acid; the structural formula is shown in formula 1i below; ； When the selenoglycoside compound is compound 2j, the selenoglycoside acceptor used is 2-methyl-4-methoxyphenylboronic acid; the structural formula is shown in formula 1j below; ； When the selenoglycoside compound is compound 2k, the selenoglycoside acceptor used is 2-methoxy-4-fluorophenylboronic acid; the structural formula is shown in formula 1k below; ； When the selenoglycoside compound is compound 2l, the selenoglycoside acceptor used is 9,9-dimethylfluorene-2-boronic acid; the structural formula is shown in Formula 1l below; ； When the selenoglycoside compound is compound 2m, the selenoglycoside acceptor used is 4-dibenzofuranboronic acid; the structural formula is shown in formula 1m below; ； When the selenoglycoside compound is compound 2n, the selenoglycoside acceptor used is phenoxathia-4-boronic acid; the structural formula is shown in formula 1n below; ； When the selenoglycoside compound is compound 2o, the selenoglycoside acceptor used is N -Boc-indole-2-boronic acid; structural formula shown in Formula 1o below; ； When the selenoglycoside compound is compound 2p, the selenoglycoside acceptor used is phenoxathia-4-boronic acid; the structural formula is shown in formula 1n below; ； When the selenoglycoside compound is compound 2q, the selenoglycoside acceptor used is 3-acetamidophenylboronic acid; the structural formula is shown in formula 1q below; ； When the selenoglycoside compound is compound 2r, the selenoglycoside acceptor used is 2-(4-methoxybenzyl)phenylboronic acid; the structural formula is shown in formula 1r below; ； When the selenoglycoside compound is compound 2s, the selenoglycoside acceptor used is 2-((2-(4-fluorophenyl)thiophen-5-yl)methyl)phenylboronic acid; the structural formula is shown in formula 1s below; ； When the selenoglycoside compound is compound 2t, the selenoglycoside acceptor used is 2-chloro-6-(4-(((S)-tetrahydrofuran-3-yl)oxy)benzyl)phenylboronic acid; the structural formula is shown in formula 1t below; 。 9. The synthesis method according to claim 7, characterized in that, The method for synthesizing the selenoglycoside donor S6 is as follows: C1: Selenium powder was dissolved in ethanol, and sodium borohydride was slowly added under an ice bath at 0°C until no more gas was produced in the system. 4-Methylbenzoyl chloride was added dropwise, and the mixture was stirred thoroughly for 30 min. Separately, elemental iodine and potassium iodide were dissolved in ethanol and added dropwise to the reaction system, and the mixture was stirred thoroughly for 30 min. The reaction was monitored by TLC until complete. The reaction was quenched with saturated sodium bicarbonate solution, diluted with dichloromethane, washed with water, evaporated to dryness, and then recrystallized from dichloromethane and petroleum ether. The mixture was filtered to obtain the intermediate compound S2. The molar ratio of 4-methylbenzoyl chloride, selenium powder, sodium borohydride, elemental iodine, and potassium iodide was 1:1:1.2:1:0.

2. C2: Dissolve intermediate compound S2 in toluene, add 1M potassium hydroxide methanol solution, react at room temperature for 10 min, remove solvent by rotary evaporation, wash with petroleum ether, and filter to obtain intermediate compound S3; C3: The intermediate compound S3 and 2,3,4,6- O Acetyl-D-pyranose bromide was dissolved in ethyl acetate, and tetrabutylammonium bisulfate and sodium carbonate aqueous solution were added. The mixture was reacted at room temperature for three hours, and the reaction was monitored by TLC until complete. The solution was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography to give intermediate compound S4; wherein intermediate compounds S3, 2,3,4,6- O The molar ratio of acetyl-D-pyranose bromide to tetrabutylammonium hydrogen sulfate is 2:1:2; C4: Dissolve intermediate compound S4 in N,N-dimethylformamide, add piperazine, react at room temperature for 10 min, monitor the reaction for completeness by TLC, dilute with ethyl acetate, wash with 1M HCl solution and saturated brine, evaporate the solvent, and purify by column chromatography to obtain intermediate compound S5; wherein the molar ratio of intermediate compound S4 to piperazine is 1:1.

25. C5: The intermediate compound S5 was dissolved in anhydrous acetonitrile, and sodium p-methylsulfinate and sulfoxide were added. The mixture was reacted at room temperature for 12 h. The reaction was monitored by TLC until it was complete. The reaction system was diluted with ethyl acetate, washed with water, and the solvent was evaporated. The target selenoglycoside donor S6 was purified by column chromatography. The molar ratio of intermediate compound S5, sodium p-methylsulfinate, and sulfoxide was 1:10:

3.

10. The synthesis method according to claim 7, characterized in that, The method for synthesizing the selenoglycoside donor S9 is as follows: D1: Selenium powder was dissolved in ethanol, and sodium borohydride was slowly added under an ice bath at 0°C until no more gas was produced in the system. 4-methylbenzoyl chloride was added dropwise, and the mixture was stirred thoroughly for 30 min. Separately, elemental iodine and potassium iodide were dissolved in ethanol and added dropwise to the reaction system, and the mixture was stirred thoroughly for 30 min. The reaction was monitored by TLC until complete. The reaction was quenched with saturated sodium bicarbonate solution, diluted with dichloromethane, washed with water, evaporated to dryness, and recrystallized from dichloromethane and petroleum ether. The mixture was then filtered to obtain the intermediate compound S2. The molar ratio of 4-methylbenzoyl chloride, selenium powder, sodium borohydride, elemental iodine, and potassium iodide was 1:1:1.2:1:0.

2. D2: Dissolve intermediate compound S2 in toluene, add 1M potassium hydroxide methanol solution, react at room temperature for 10 min, remove solvent by rotary evaporation, wash with petroleum ether, and filter to obtain intermediate compound S3. D3: The intermediate compound S3 and 2,3,4,6- O Acetyl-D-pyranogalactose bromide was dissolved in ethyl acetate, and tetrabutylammonium bisulfate and sodium carbonate aqueous solution were added. The mixture was reacted at room temperature for three hours, and the reaction was monitored by TLC until complete. The solution was diluted with ethyl acetate, washed with saturated brine, evaporated to dryness, and purified by column chromatography to give intermediate compound S7; wherein intermediate compounds S3, 2,3,4,6- O The molar ratio of acetyl-D-galactopyranose bromide to tetrabutylammonium hydrogen sulfate is 2:1:2; D4: Dissolve intermediate compound S7 in N,N-dimethylformamide, add piperazine, react at room temperature for 10 min, monitor the reaction for completeness by TLC, dilute with ethyl acetate, wash with 1M HCl solution and saturated brine, evaporate the solvent, and purify by column chromatography to obtain intermediate compound S8; wherein the molar ratio of intermediate compound S7 to piperazine is 1:1.

25. D5: Dissolve intermediate compound S8 in anhydrous acetonitrile, add sodium p-methylsulfinate and sulfoxide, react at room temperature for 12 h, monitor the reaction for completeness by TLC, dilute the reaction system with ethyl acetate, wash with water, evaporate the solvent, and purify by column chromatography to obtain selenoglycoside donor S9; wherein the molar ratio of intermediate compound S8, sodium p-methylsulfinate and sulfoxide is 1:10:2.7.

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