A synthetic method of chondroitin polysaccharide ABW90-1 and / or ABW50-1

Abstract

The application provides a synthesis method of chondroitin polysaccharide ABW90-1 and / or chondroitin polysaccharide ABW50-1, and relates to the technical field of polysaccharide preparation.The synthesis method provided by the application adopts a fructose 6-position picoloyl group as a guiding group, highly stereoselectively constructs beta-(2 to 6)-D-furan fructose and internal beta-(2 to 1)-D-furan fructose glycosidic bonds through a glycoside unit transfer strategy mediated by hydrogen bonds, and efficiently prepares chondroitin polysaccharide ABW90-1 and chondroitin polysaccharide ABW50-1.The synthesis method provided by the application has the advantages of simplicity, high efficiency, high target product yield and high purity, and has reference significance for the synthesis of other types of sucrose oligosaccharides.

Description

Technical Field

[0001] This invention relates to the field of polysaccharide preparation technology, specifically to a method for synthesizing Achyranthes bidentata polysaccharide ABW90-1 and / or ABW50-1. Background Technology

[0002] The dried root of Achyranthes bidentata is widely used as a prescription drug for treating osteoporosis. Polysaccharides extracted from Achyranthes bidentata possess various biological functions, including antiviral, antitumor, antioxidant, and anti-osteoporosis effects. In 2017, Yan Chunyan's research group isolated a novel branched-chain fructooligosaccharide, ABW90-1, from the root of Achyranthes bidentata. In vitro biological studies showed that ABW90-1 has a good promoting effect on the proliferation and differentiation of primary osteoblasts (Industr. Crops Prod., 2017, 108, 458). In 2019, Yan Chunyan's research group further isolated another novel branched-chain fructooligosaccharide, ABW50-1, from the root of Achyranthes bidentata (Carbohydr. Polym., 2019, 210, 110). Interestingly, in a zebrafish model of osteoporosis induced by glucocorticoids, ABW50-1 was shown to significantly increase bone strength without side effects, suggesting that ABW50-1 may be used to develop new carbohydrate-based treatments for osteoporosis.

[0003] Structurally, both ABW90-1 and ABW50-1, as branched oligofructoses, have two β-(2→6)-D-fructofuranosyl bonds, while ABW50-1 has four β-(2→1)-D-fructofuranosyl bonds and ABW90-1 has three. Their unique structure and effective anti-osteoporosis activity have attracted researchers to conduct total chemical synthesis of Achyranthes bidentata polysaccharides ABW90-1 and ABW50-1 for in-depth biological research. However, due to the heterogeneity of sugar structure, it is very difficult to isolate and extract high-purity and large-scale quantities of Achyranthes bidentata polysaccharides ABW90-1 and ABW50-1 from nature. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a method for synthesizing Achyranthes bidentata polysaccharide ABW90-1 and / or ABW50-1. The preparation method provided by the present invention can efficiently prepare Achyranthes bidentata polysaccharide ABW90-1 and ABW50-1.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for synthesizing Achyranthes bidentata polysaccharide ABW90-1 and / or Achyranthes bidentata polysaccharide ABW50-1, comprising the following steps:

[0007] Compounds 3 and 4 were subjected to a first glycosylation reaction to form a β-(2→1)-D-fructofuranosyl bond, yielding compound 6;

[0008] Compound 6 was subjected to a first depico protecting group reaction to obtain compound 7.

[0009] The C6-OH of the terminal sugar of compound 7 was subjected to a first Bz protecting group introduction reaction to give compound 8;

[0010] Compound 8 was subjected to a first deprotection reaction to obtain compound 9;

[0011] Compound 9 and compound 4 were subjected to a second glycosylation reaction to form a β-(2→1)-D-fructofuranosyl glycosidic bond to obtain compound 10;

[0012] Compound 10 was subjected to a second depico protecting group reaction to obtain compound 11;

[0013] Compound 7 or compound 11 is subjected to a third glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 12 or compound 13;

[0014] Compound 12 or 13 is subjected to a third depico protecting group reaction to obtain compound 14 or 15.

[0015] Compound 14 or 15 is subjected to a fourth glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 16 or 17.

[0016] Compound 16 or 17 is subjected to a fourth depico protecting group reaction to obtain compound 18 or 19.

[0017] A second Bz protecting group introduction reaction is carried out at the C6-OH of the terminal sugar of compound 18 or compound 19 to give compound 20 or compound 21.

[0018] Compound 20 or compound 21 is subjected to a second deprotection reaction to obtain compound 22 or compound 23;

[0019] Compound 22 or 23 is subjected to a fifth glycosylation reaction with compound 5 to form a β-(2→1)-D-fructofuranosyl glycosidic bond, yielding compound 24 or 25.

[0020] Compound 24 or 25 is subjected to a benzoyl group removal and Pico protecting group removal reaction to obtain compound 26 or 27;

[0021] The compound 26 or compound 27 was subjected to a debenzyl protecting group reaction to obtain Achyranthes bidentata polysaccharide ABW90-1 or Achyranthes bidentata polysaccharide ABW50-1;

[0022]

[0023]

[0024]

[0025] Preferably, the first glycosylation reaction, the second glycosylation reaction, the third glycosylation reaction, the fourth glycosylation reaction, and the fifth glycosylation reaction are all carried out in the presence of an accelerator, an additive, and a first solvent;

[0026] The accelerator includes one or more of N-iodosuccinimide, N-bromosuccinimide, TfOH, trimethylsilyl trifluoromethanesulfonate, and dibromohydantoin;

[0027] The additives include Molecular sieves;

[0028] The first solvent includes one or more of toluene, dichloromethane, dichloroethane, and acetonitrile;

[0029] The temperatures for the first, second, third, and fourth glycosylation reactions are independently -25 to -15°C, and the temperature for the fifth glycosylation reaction is -78°C to -35°C.

[0030] Preferably, the first, second, third, and fourth depico protecting group reactions are all carried out in the presence of the depico reagent and the second solvent;

[0031] The depico-removing reagent includes Cu(OAc)2;

[0032] The second solvent includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform.

[0033] Preferably, both the first and second reactions of introducing Bz protecting groups are carried out in the presence of Bz protecting group reagent, organic base and third solvent;

[0034] The Bz protecting group reaction reagents include benzoyl chloride and / or benzoic anhydride;

[0035] The organic base includes one or more of triethylamine, 2,6-dimethylpyridine, diisopropylethylamine, and pyridine;

[0036] The third solvent includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine.

[0037] Preferably, both the first and second Nap-protection reactions are carried out in the presence of the Nap-protection reagent and the fourth solvent.

[0038] The deNap-removing reagent includes 2,3-dichloro-5,6-dicyanobenzoquinone;

[0039] The fourth solvent includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform.

[0040] Preferably, the debenzoylation and Pico protecting group reaction is carried out in the presence of a deprotecting agent and a fifth solvent;

[0041] The deprotection reagent includes one or more of alkali metal alkoxides, alkali metal hydroxides, and alkali metal carbonates;

[0042] The fifth solvent includes a mixed solvent of dichloromethane and methanol, a mixed solvent of dichloroethane and ethanol, or isopropanol.

[0043] Preferably, the debenzylation protecting group reaction is carried out in the presence of a debenzylation protecting agent and a sixth solvent;

[0044] The debenzyl protecting agent comprises a palladium compound and hydrogen gas, wherein the palladium compound comprises palladium on carbon and / or palladium hydroxide, and the hydrogen gas is at a pressure of 1–30 atm.

[0045] The sixth solvent includes one or more of methanol, ethanol, tetrahydrofuran, water, isopropanol, and ethyl acetate;

[0046] The reaction temperature for the debenzylation protecting group reaction is 25–60 °C.

[0047] Preferably, the synthesis of compound 4 includes the following steps:

[0048] Compound M1 was subjected to a reaction to introduce a Nap protecting group into its Cl-OH group, yielding compound M2;

[0049] Compound M2 was subjected to a deprotection reaction to obtain compound M3;

[0050] The C6-OH of compound M3 was subjected to a Pico protecting group introduction reaction to obtain compound 4;

[0051]

[0052] Preferably, the Nap protecting group introduction reaction is carried out in the presence of Nap protecting group reaction reagent, basic reagent and seventh solvent;

[0053] The Nap protecting group reaction reagent includes 2-chloromethylnaphthalene or 2-bromomethylnaphthalene;

[0054] The alkaline reagent includes one or more of the following: triethylamine, 2,6-dimethylpyridine, diisopropylethylamine, pyridine, potassium carbonate, sodium hydride, cesium carbonate, sodium hydroxide, potassium tert-butoxide, potassium hydroxide, and potassium phosphate.

[0055] The seventh solvent includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine.

[0056] Preferably, the TBDPS removal reaction is carried out in the presence of a TBDPS removal reagent and an eighth solvent; the TBDPS removal reagent includes 3HF Et3N, HF·Pyridine, TBAF, TBAF / AcOH, or KF; the eighth solvent includes tetrahydrofuran and / or toluene;

[0057] The Pico protecting group introduction reaction is carried out in the presence of a Pico protecting group reaction reagent, a condensation reagent, a basic reagent, and a ninth solvent; the Pico protecting group reaction reagent includes 2-pyridinecarboxylic acid; the condensation reagent includes one or more of 1-ethyl-3-(3-dimethylpropylamine)carbodiimide, dicyclohexylcarbodiimide, diisopropylcarbodiimide, O-benzotriazole-N,N,N',N'-tetramethylurea tetrafluoroboronic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate, and O-benzotriazole-tetramethylurea hexafluorophosphate; the basic reagent includes one or more of 4-dimethylaminopyridine, diisopropylethylamine, and triethylamine; and the ninth solvent includes one or more of dichloromethane, tetrahydrofuran, and toluene.

[0058] The synthetic method provided by this invention uses the picoloyl group at the 6-position of fructose as a directing group. Through a hydrogen bond-mediated aglycone transfer strategy, β-(2→6)-D-fructofuranose and the internal β-(2→1)-D-fructofuranose glycosidic bond are constructed with high stereoselectivity, resulting in the efficient preparation of Achyranthes bidentata polysaccharides ABW90-1 and ABW50-1. The synthetic method provided by this invention has the advantages of simplicity, high efficiency, high yield and high purity of the target product, and has reference value for the synthesis of other types of sucrose oligosaccharides. Attached Figure Description

[0059] Figure 1This is a diagram illustrating the synthesis mechanism of Achyranthes bidentata polysaccharides ABW90-1 and ABW50-1. Detailed Implementation

[0060] This invention provides a method for synthesizing Achyranthes bidentata polysaccharide ABW90-1 and / or Achyranthes bidentata polysaccharide ABW50-1, comprising the following steps:

[0061] Compounds 3 and 4 were subjected to a first glycosylation reaction to form a β-(2→1)-D-fructofuranosyl bond, yielding compound 6;

[0062] Compound 6 was subjected to a first depico protecting group reaction to obtain compound 7.

[0063] The C6-OH of the terminal sugar of compound 7 was subjected to a first Bz protecting group introduction reaction to give compound 8;

[0064] Compound 8 was subjected to a first deprotection reaction to obtain compound 9;

[0065] Compound 9 and compound 4 were subjected to a second glycosylation reaction to form a β-(2→1)-D-fructofuranosyl glycosidic bond to obtain compound 10;

[0066] Compound 10 was subjected to a second depico protecting group reaction to obtain compound 11;

[0067] Compound 7 or compound 11 is subjected to a third glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 12 or compound 13;

[0068] Compound 12 or 13 is subjected to a third depico protecting group reaction to obtain compound 14 or 15.

[0069] Compound 14 or 15 is subjected to a fourth glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 16 or 17.

[0070] Compound 16 or 17 is subjected to a fourth depico protecting group reaction to obtain compound 18 or 19.

[0071] A second Bz protecting group introduction reaction is carried out at the C6-OH of the terminal sugar of compound 18 or compound 19 to give compound 20 or compound 21.

[0072] Compound 20 or compound 21 is subjected to a second deprotection reaction to obtain compound 22 or compound 23;

[0073] Compound 22 or 23 is subjected to a fifth glycosylation reaction with compound 5 to form a β-(2→1)-D-fructofuranosyl glycosidic bond, yielding compound 24 or 25.

[0074] Compound 24 or 25 is subjected to a benzoyl group removal and Pico protecting group removal reaction to obtain compound 26 or 27;

[0075] The compound 26 or compound 27 was subjected to a debenzyl protecting group reaction to obtain Achyranthes bidentata polysaccharide ABW90-1 or Achyranthes bidentata polysaccharide ABW50-1;

[0076]

[0077]

[0078]

[0079] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0080] In this invention, compounds 3 and 4 are subjected to a first glycosylation reaction to form a β-(2→1)-D-fructofuranosyl glycosidic bond, yielding compound 6.

[0081] In this invention, the molar ratio of compound 4 (donor) to compound 3 (acceptor) is preferably 1 to 10:1, more preferably 1.1 to 5:1, and even more preferably 1.3 to 2:1. In this invention, the C1 protecting group in compound 4 is a hydroxyl protecting group, and the hydroxyl protecting group is 2-naphthylene.

[0082] In this invention, the first glycosylation reaction is preferably carried out in the presence of an accelerator, an additive, and a first solvent. Specifically, compound 3, compound 4, the accelerator, the additive, and the first solvent are mixed to carry out the first glycosylation reaction.

[0083] In this invention, the accelerator preferably includes one or more of N-iodosuccinimide (NIS), N-bromosuccinimide (NBS), trifluoromethanesulfonic acid (TfOH), trimethylsilyl trifluoromethanesulfonate (TMSOTf), and dibromohydantoin (DBDMH), more preferably dibromohydantoin. In this invention, the molar ratio of the accelerator to compound 3 is preferably 1–10:1, more preferably 1.1–5:1, and even more preferably 1.3–2:1.

[0084] In this invention, the additive preferably includes Molecular sieve. In this invention, the mass ratio of the additive to compound 3 is preferably 2 to 4:1, more preferably 2.5 to 3:1.

[0085] In this invention, the first solvent preferably includes one or more of toluene, dichloromethane, dichloroethane, and acetonitrile, with dichloromethane being the most preferred; the first solvent is preferably a dry first solvent; this invention does not have a special limitation on the amount of the first solvent used, as long as it can ensure that the first glycosylation reaction proceeds smoothly.

[0086] In this invention, the mixing is preferably carried out by dissolving compound 4 and compound 3 in a first solvent, adding an additive, stirring under a protective atmosphere for 15 to 30 minutes (more preferably 20 to 30 minutes), and then adding an accelerator and mixing evenly.

[0087] In this invention, the temperature of the first glycosylation reaction is preferably -25 to -15°C, more preferably -20°C, and the time is preferably 2 to 5 hours, more preferably 2 to 3 hours; the first glycosylation reaction is preferably carried out under a protective atmosphere, which preferably includes nitrogen, argon or helium.

[0088] After completing the first glycosylation reaction, the present invention preferably further includes: quenching the obtained first glycosylation reaction solution with triethylamine, then diluting it with the first solvent, washing it with water, washing it with saturated brine, drying it with anhydrous sodium sulfate, filtering it, and then purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound 6. In the present invention, the eluent used for silica gel column chromatography is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 4:1 to 3:1.

[0089] After compound 6, the present invention performs a first deprotection reaction on compound 6 to obtain compound 7.

[0090] In this invention, the first depico protecting group reaction is preferably carried out in the presence of a depico reagent and a second solvent. Specifically, compound 6, the depico reagent, and the second solvent are mixed to carry out the first depico protecting group reaction.

[0091] In this invention, the depico-removing reagent preferably comprises Cu(OAc)2. In this invention, the molar ratio of compound 6 to the depico-removing reagent is preferably 1–10:1, more preferably 1.1–5:1, and even more preferably 1.3–2:1.

[0092] In this invention, the second solvent preferably includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform, more preferably a mixed solvent of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol in the mixed solvent is preferably 1 to 20:1; this invention does not have a special limitation on the amount of the second solvent, as long as it can ensure that the first depico protecting group removal reaction proceeds smoothly.

[0093] In this invention, the temperature of the first depico protecting reaction is preferably room temperature, and the time is preferably 3 to 5 hours, more preferably 3 to 4 hours.

[0094] After completing the first depico protecting group removal reaction, the present invention preferably further includes: diluting the obtained first depico protecting group removal reaction solution with the aforementioned solvent, washing with water, washing with saturated brine, drying with anhydrous sodium sulfate, filtering, and then purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound 7. In the present invention, the eluent used for silica gel column chromatography purification is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 5:1 to 3:1.

[0095] After obtaining compound 7, the present invention performs a first Bz protecting group introduction reaction on the C6-OH of the terminal sugar of compound 7 to obtain compound 8.

[0096] In this invention, the first Bz protecting group introduction reaction is preferably carried out in the presence of a Bz protecting group reaction reagent, an organic base, and a third solvent. Specifically, the compound 7, the Bz protecting group reaction reagent, the organic base, and the third solvent are mixed to carry out the first Bz protecting group introduction reaction.

[0097] In this invention, the Bz protecting group reaction reagent preferably includes benzoyl chloride and / or benzoic anhydride; the molar ratio of compound 7 and the Bz protecting group reaction reagent is preferably 1:1 to 3, more preferably 1:1.1 to 2, and even more preferably 1:1.3 to 1.5.

[0098] In this invention, the organic base preferably includes one or more of triethylamine, 2,6-dimethylpyridine, diisopropylethylamine and pyridine; the molar ratio of compound 7 to the organic base is preferably 1:1 to 5, more preferably 1:1 to 3, and even more preferably 1:1 to 1.5.

[0099] In this invention, the third solvent preferably includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine; the amount of the third solvent is not particularly limited in this invention, as long as it is sufficient to ensure the smooth progress of the first Bz protecting group introduction reaction.

[0100] In this invention, the temperature of the first Bz-protecting group introduction reaction and the second Bz-protecting group introduction reaction is preferably 40-60°C, more preferably 50°C, and the time is preferably 1-3 hours, more preferably 2 hours.

[0101] After completing the first Bz-protecting group introduction reaction, the present invention preferably further includes: diluting the obtained first Bz-protecting group introduction reaction solution with the third solvent, washing it sequentially with hydrochloric acid solution, saturated sodium bicarbonate aqueous solution, and saturated brine, drying it with anhydrous sodium sulfate, filtering it, and then purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound 8. In the present invention, the concentration of the hydrochloric acid solution is preferably 0.5-2 mol / L, more preferably 1 mol / L. In the present invention, the eluent used for silica gel column chromatography is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 5:1-3:1, more preferably 3.5:1.

[0102] After obtaining compound 8, the present invention performs a first deprotection reaction on compound 8 to obtain compound 9.

[0103] In this invention, the first deNap protecting group reaction is preferably carried out in the presence of a deNap reagent and a fourth solvent. Specifically, the compound 8, the deNap reagent, and the fourth solvent are mixed to carry out the first deNap protecting group reaction.

[0104] In this invention, the denap-removing reagent preferably comprises 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). In this invention, the molar ratio of compound 8 to the denap-removing reagent is preferably 1:1 to 3, more preferably 1:1.5 to 2.5, and even more preferably 1:2.

[0105] In this invention, the fourth solvent preferably includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform, more preferably a mixed solvent of dichloromethane and methanol, wherein the volume ratio of dichloromethane to methanol in the mixed solvent is preferably 1 to 20:1; this invention does not have a special limitation on the amount of the fourth solvent, as long as it can ensure that the first deprotection reaction of the Nap group proceeds smoothly.

[0106] In this invention, the temperature of the first Nap-protecting group removal reaction is preferably room temperature, and the time is preferably 10-15 h, more preferably 12 h.

[0107] After completing the first Nap-protecting group removal reaction, the present invention preferably further includes: diluting the obtained first Nap-protecting group removal reaction solution with the fourth solvent, washing with water, washing with saturated brine, drying with anhydrous sodium sulfate, filtering, and purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound 6. In the present invention, the eluent used for silica gel column chromatography is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 3:1 to 4:1, more preferably 3.5:1.

[0108] After obtaining compound 9, the present invention performs a second glycosylation reaction on compound 9 (acceptor) and compound 4 (donor) to form a β-(2→1)-D-fructofuranosyl glycosidic bond, yielding compound 10. In the present invention, except for the different raw materials, the preparation conditions of compound 10 are preferably the same as those of compound 6, and will not be repeated here.

[0109] After obtaining compound 10, the present invention subjectes compound 10 to a second depico protecting group reaction to obtain compound 11. In the present invention, except for the different raw materials, the preparation conditions of compound 10 are preferably the same as those of compound 7, and will not be repeated here. In the present invention, the reactions occurring during the second depico protecting group reaction are as follows.

[0110] After obtaining compounds 7 and 11, the present invention involves subjecting either compound 7 or compound 11 (acceptor) to compound 5 (donor) via a third glycosylation reaction to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 12 or compound 13. In this invention, except for the different raw materials, the preparation conditions for compounds 12 and 13 are preferably the same as those for compound 6, and will not be repeated here.

[0111] After obtaining compound 12 or compound 13, the present invention performs a third depico protecting reaction on compound 12 or compound 13 to obtain compound 14 or compound 15. In the present invention, except for the different raw materials, the preparation conditions of compound 14 and compound 15 are preferably the same as those of compound 7, and will not be repeated here.

[0112] After obtaining compound 14 or compound 15, the present invention performs a fourth glycosylation reaction on compound 14 or compound 15 with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 16 or compound 17. In the present invention, except for the different raw materials, the preparation conditions of compound 12 and compound 13 are the same as those of compound 6, and will not be repeated here.

[0113] After obtaining compound 16 or compound 17, the present invention subjectes compound 16 or compound 17 to a fourth deprotection reaction to obtain compound 18 or compound 19. In the present invention, except for the different raw materials, the preparation conditions of compound 18 and compound 19 are preferably the same as those of compound 7, and will not be repeated here.

[0114] After obtaining compound 18 or compound 19, the present invention performs a second Bz protecting group introduction reaction on the C6-OH of the terminal sugar of compound 18 or compound 19 to obtain compound 20 or compound 21. In the present invention, except for the different raw materials, the preparation conditions of compound 20 and compound 21 are preferably the same as those of compound 8, and will not be repeated here.

[0115] After obtaining compound 20 or compound 21, the present invention subjectes compound 20 or compound 21 to a second deprotection reaction to obtain compound 22 or compound 23. In the present invention, except for the different raw materials, the preparation conditions of compound 22 and compound 23 are preferably the same as those of compound 9, and will not be repeated here.

[0116] After obtaining compound 22 or compound 23, the present invention performs a fifth glycosylation reaction on compound 22 or compound 23 with compound 5 to form a β-(2→1)-D-fructofuranosyl glycosidic bond, thereby obtaining compound 24 or compound 25.

[0117] In this invention, the temperature of the fifth glycosylation reaction is preferably -78°C to -35°C. In this invention, the fifth glycosylation reaction is preferably carried out in the presence of a promoter, an additive, and a first solvent. Specifically, compound 22 or compound 23, compound 5, a promoter, an additive, and a first solvent are mixed to carry out the first glycosylation reaction. In this invention, the mixing preferably includes: mixing compound 22 or 23, the promoter, and the additive; adding the first solvent under a protective atmosphere; mixing at -78°C; then adding a solution of compound 5 dropwise; and raising the temperature to -35°C to carry out the fifth glycosylation reaction.

[0118] In this invention, the other preparation conditions of compound 24 or compound 25 are the same as those of compound 6, and will not be repeated here.

[0119] After obtaining compound 24 or compound 25, the present invention performs a benzoyl and Pico protecting group removal reaction on compound 24 or compound 25 to obtain compound 26 or compound 27.

[0120] In this invention, the debenzoylation and Pico protecting group reaction is preferably carried out in the presence of a deprotecting reagent and a fifth solvent; specifically, compound 24 or compound 25, the deprotecting reagent and the fifth solvent are mixed to carry out the debenzoylation and Pico protecting group reaction.

[0121] In this invention, the deprotecting agent preferably includes one or more of alkali metal alkoxides, alkali metal hydroxides, and alkali metal carbonates, and more preferably includes one or more of sodium methoxide, potassium carbonate, sodium hydroxide, and potassium hydroxide. In this invention, the molar ratio of compound 24 or compound 25 to the deprotecting agent is preferably 1:1 to 5, more preferably 1:2 to 3; in a specific embodiment of this invention, the amount of the deprotecting agent used is sufficient to adjust the pH of the system to 11.

[0122] In this invention, the fifth solvent preferably includes a mixed solvent of dichloromethane and methanol, a mixed solvent of dichloroethane and ethanol, or isopropanol. The volume ratio of methanol (or ethanol) to dichloromethane in the mixed solvent is preferably 5 to 15:1, more preferably 10:1. This invention does not have a special limitation on the amount of the fifth solvent, as long as it can ensure the smooth progress of the benzoyl removal and Pico protecting group reaction.

[0123] In this invention, the temperature of the debenzoylation and Pico protecting group reaction is preferably room temperature, and the time is preferably 40-55 h, more preferably 48 h.

[0124] After completing the benzoyl removal and Pico protecting group reaction, the present invention preferably further includes: neutralizing the obtained benzoyl removal and Pico protecting group reaction solution to neutral, filtering, concentrating the obtained liquid component, and then purifying it by silica gel column chromatography to obtain compound 26 or compound 27. In the present invention, the neutralizing acid solution preferably includes hydrochloric acid solution, and the concentration of the acid solution is preferably 1-4 mol / L, more preferably 3 mol / L. In the present invention, the eluent used for silica gel column chromatography purification is preferably a mixed solvent of methanol and dichloromethane, and the volume ratio of methanol to dichloromethane is preferably 9-11:1, more preferably 10:1.

[0125] After obtaining compound 26 or compound 27, the present invention performs a debenzylation reaction on compound 26 or compound 27 to obtain Achyranthes bidentata polysaccharide ABW90-1 or Achyranthes bidentata polysaccharide ABW50-1.

[0126] In this invention, the debenzylation protecting group reaction is carried out in the presence of a debenzylation protecting reagent and a sixth solvent. Specifically, compound 26 or compound 27, the debenzylation protecting reagent and the sixth solvent are mixed to carry out the debenzylation protecting group reaction.

[0127] In this invention, the debenzylation protecting agent preferably comprises a palladium compound and hydrogen gas; the palladium compound preferably comprises palladium on carbon and / or palladium hydroxide, more preferably one or more of 10% palladium on carbon, 5% palladium on carbon, and 10% palladium hydroxide; the pressure of the hydrogen gas is preferably 1-30 atm, more preferably 1-5 atm. In this invention, the molar ratio of benzyl group in compound 26 or compound 27 to palladium in the palladium compound is preferably 1:1-2, more preferably 1:1.5.

[0128] In this invention, the sixth solvent preferably includes one or more of methanol, ethanol, tetrahydrofuran, water, isopropanol and ethyl acetate, more preferably a mixed solvent of tetrahydrofuran, methanol and water, wherein the volume ratio of tetrahydrofuran, methanol and water in the mixed solvent is preferably 1.5-2:9-10:1; the present invention does not have a special limitation on the amount of the sixth solvent, as long as it can ensure the smooth progress of the debenzylation protecting group reaction.

[0129] In this invention, the reaction temperature of the debenzylidene protecting group reaction is preferably room temperature, and the reaction time is 20-30 h, more preferably 24 h.

[0130] After completing the debenzylation protecting group reaction, the present invention preferably further includes: filtering the obtained debenzylation protecting group reaction solution, concentrating the obtained liquid component under vacuum, and then purifying it using a Sephadex™ LH-20 gel column. In the present invention, the eluent used for the Sephadex™ LH-20 gel column purification preferably includes an aqueous methanol solution, wherein the volume ratio of methanol to water in the aqueous methanol solution is preferably 4-6:4-6, more preferably 1:1.

[0131] In this invention, the synthesis of compound 4 preferably includes the following steps:

[0132] Compound M1 was subjected to a reaction to introduce a Nap protecting group into its Cl-OH group, yielding compound M2;

[0133] Compound M2 was subjected to a deprotection reaction to obtain compound M3;

[0134] The C6-OH of compound M3 was subjected to a Pico protecting group introduction reaction to obtain compound 4;

[0135]

[0136] In this invention, a Nap protecting group is introduced into the Cl-OH group of compound M1 to obtain compound M2.

[0137] In this invention, the Nap protecting group introduction reaction is preferably carried out in the presence of Nap protecting group reaction reagent, tetrabutylammonium iodide (TBAI), basic reagent and seventh solvent. Specifically, compound M1, Nap protecting group reaction reagent, tetrabutylammonium iodide, basic reagent and seventh solvent are mixed to carry out the Nap protecting group introduction reaction.

[0138] In this invention, the Nap protecting group reagent preferably includes 2-chloromethylnaphthalene (2-NapCl) or 2-bromomethylnaphthalene (2-NapBr). In this invention, the molar ratio of compound M1 to the Nap protecting group reagent is preferably 1:1 to 3, more preferably 1:1.2 to 2.5, and even more preferably 1:1.5 to 2.

[0139] In this invention, the molar ratio of compound M1 to tetrabutylammonium iodide is preferably 1:0.2 to 0.4, more preferably 1:0.3.

[0140] In this invention, the alkaline reagent preferably includes one or more of the following: triethylamine, 2,6-dimethylpyridine, diisopropylethylamine, pyridine, potassium carbonate, sodium hydride, cesium carbonate, sodium hydroxide, potassium tert-butoxide, potassium hydroxide, and potassium phosphate. In this invention, the molar ratio of compound M1 to the alkaline reagent is preferably 1:1 to 5, more preferably 1:1.5 to 4, and even more preferably 1:2 to 3.

[0141] In this invention, the seventh solvent preferably includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine; the seventh organic solvent is preferably a dry seventh solvent; this invention does not have a special limitation on the amount of the seventh solvent, as long as it can ensure that the reaction of introducing the Nap protecting group proceeds smoothly.

[0142] In this invention, the mixing preferably includes: dissolving compound M1 in a seventh solvent, adding a Nap protecting group reaction reagent and tetrabutylammonium iodide, and mixing with an alkaline reagent at -5 to 5°C (more preferably 0°C).

[0143] In this invention, the temperature of the reaction to introduce the Nap protecting group is preferably room temperature, and the time is preferably 4 to 6 hours, more preferably 5 hours.

[0144] After completing the Nap-protecting group introduction reaction, the present invention preferably further includes: quenching the obtained Nap-protecting group introduction reaction solution with water under ice bath, extracting with ethyl acetate 3-4 times (more preferably 3 times), combining the organic layers, washing with water 2-3 times (more preferably 2 times), washing once with saturated sodium chloride solution, drying with anhydrous sodium sulfate, filtering, and purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound M2. In the present invention, the eluent used for silica gel column chromatography purification is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 30:1 to 20:1.

[0145] After obtaining compound M2, the present invention performs a deprotection reaction of compound M2 to obtain compound M3.

[0146] In this invention, the TBDPS removal reaction is preferably carried out in the presence of a TBDPS removal reagent and an eighth solvent. Specifically, the compound M2, the TBDPS removal reagent, and the eighth solvent are mixed to carry out the TBDPS removal reaction.

[0147] In this invention, the TBDPS removal reagent preferably includes 3HF Et3N, HF·Pyridine, TBAF, TBAF / AcOH, or KF. In this invention, the molar ratio of compound M2 to the TBDPS removal reagent is preferably 1:1 to 3, more preferably 1:1.2 to 2.5, and even more preferably 1:1.5 to 2.

[0148] In this invention, the eighth solvent preferably includes tetrahydrofuran and / or toluene; the amount of the eighth solvent is not particularly limited, as long as it is sufficient to ensure the smooth progress of the TBDPS deprotection reaction.

[0149] In this invention, the temperature of the deprotection reaction of the TBDPS group is preferably room temperature, and the time is preferably 2 to 4 hours, more preferably 3 hours.

[0150] After completing the TBDPS deprotection reaction, the present invention preferably further includes quenching the obtained TBDPS deprotection reaction solution with a saturated ammonium chloride solution, extracting with ethyl acetate 2-4 times (more preferably 3 times), combining the organic layers, washing with water 2-3 times (more preferably 2 times), washing once with a saturated sodium chloride solution, drying with anhydrous sodium sulfate, filtering, and then purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound M2. In the present invention, the eluent used for silica gel column chromatography is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 3-5:1, more preferably 4:1.

[0151] After obtaining compound M3, the present invention introduces a Pico protecting group into the C6-OH of compound M3 to obtain compound 4.

[0152] In this invention, the Pico protecting group introduction reaction is preferably carried out in the presence of a Pico protecting group reaction reagent, a condensation reagent, a basic reagent, and a ninth solvent. Specifically, the compound M3, the Pico protecting group reaction reagent, the condensation reagent, the basic reagent, and the ninth solvent are mixed to carry out the Pico protecting group introduction reaction.

[0153] In this invention, the Pico protecting group reagent preferably includes 2-pyridinecarboxylic acid. In this invention, the molar ratio of compound M2 to the Pico protecting group reagent is preferably 1:1 to 3, more preferably 1:1.2 to 2.5, and even more preferably 1:1.5 to 2.

[0154] In this invention, the condensing agent preferably includes one or more of 1-ethyl-3-(3-dimethylpropylamine)carbodiimide (EDCI), dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), O-benzotriazole-N,N,N',N'-tetramethylurea tetrafluoroborate (TBTU), 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate (HATU), and O-benzotriazole-tetramethylurea hexafluorophosphate (HBTU). In this invention, the molar ratio of compound M2 to the condensing agent is preferably 1:1 to 3, more preferably 1:1.2 to 2.5, and even more preferably 1:1.5 to 2.

[0155] In this invention, the alkaline reagent (used as a catalyst) is selected from one or more of 4-dimethylaminopyridine (DAMP), diisopropylethylamine, and triethylamine. In this invention, the molar ratio of compound M2 to the alkaline reagent is preferably 1:0.05 to 0.5, more preferably 1:0.1 to 0.4, and even more preferably 1:0.15 to 0.2.

[0156] In this invention, the ninth solvent preferably includes one or more of dichloromethane, tetrahydrofuran, and toluene; the amount of the ninth solvent is not particularly limited in this invention, as long as it can ensure that the reaction of introducing the Pico protecting group proceeds smoothly.

[0157] In this invention, the temperature of the reaction to introduce the Pico protecting group is preferably room temperature, and the time is preferably 10 to 14 hours, more preferably 12 hours.

[0158] After completing the Pico protecting group introduction reaction, the present invention preferably further includes: extracting the obtained Pico protecting group introduction reaction solution with ethyl acetate 2 to 4 times (more preferably 3 times), combining the organic layers, washing with water, washing with saturated sodium chloride solution, drying with anhydrous sodium sulfate, filtering, and purifying the obtained liquid component by vacuum concentration and silica gel column chromatography to obtain compound 4. In the present invention, the eluent used for silica gel column chromatography purification is preferably a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is preferably 3 to 5:1, more preferably 4:1.

[0159] The synthetic method provided by this invention uses the picoloyl group at the 6-position of fructose as a directing group. Through a hydrogen bond-mediated aglycone transfer strategy, it highly stereoselectively constructs β-(2→6)-D-fructofuranose and the internal β-(2→1)-D-fructofuranose glycosidic bond, efficiently preparing Achyranthes bidentata polysaccharides ABW90-1 and ABW50-1 (synthetic mechanism as follows). Figure 1 As shown in the figure, the synthesis method provided by the present invention has the advantages of being simple, efficient, and having a high yield and high purity of the target product, and has reference value for the synthesis of other types of sucrose oligosaccharides.

[0160] To further illustrate the present invention, the synthesis methods of Achyranthes bidentata polysaccharide ABW90-1 and / or Achyranthes bidentata polysaccharide ABW50-1 are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0161] Example 1

[0162] 1. Synthesis and characterization of compound 4

[0163]

[0164] S1: Compound M1 (2.01 g, 3.13 mmol, 1.0 equivalent) was dissolved in a dry tetrahydrofuran solution (28 mL). 2-Bromomethylnaphthalene (NapBr) (1.03 g, 4.69 mmol, 1.5 equivalent) and tetrabutylammonium iodide (TBAI) (347 mg, 0.94 mmol, 0.3 equivalent) were added to the flask, and sodium hydride (NaH) (60%, 225 mg, 9.39 mmol, 3.0 equivalent) was slowly added at 0 °C. The reaction was then stirred at room temperature for 5 h. TLC monitoring showed complete reaction of the starting material. The reaction was quenched with water in an ice bath. The mixture was extracted three times with ethyl acetate, and the organic layers were combined. The layers were washed twice with water and once with saturated sodium chloride solution. The mixture was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. Purification was performed by silica gel column chromatography (petroleum ether:ethyl acetate volume ratio = 30:1 to 20:1) to obtain a colorless syrup compound M2 (2 g, yield 82%).

[0165] S2: Compound M2 (2 g, 2.55 mmol, 1.0 equiv.) and tetrabutylammonium fluoride (TBAF) (3.83 mL, 3.83 mmol, 1 M in THF, 1.5 equiv.) were added to a round-bottom flask and dissolved in tetrahydrofuran (THF) (25 mL). The mixture was stirred at room temperature for 3 h, quenched with saturated ammonium chloride solution, extracted three times with ethyl acetate, and the organic layers were combined. The mixture was washed twice with water and once with saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The purified compound was purified by silica gel column chromatography (petroleum ether:ethyl acetate v / v = 4:1) to give a pale yellow compound M3 (1.30 g, yield 94%).

[0166] S3: Compound M3 (1.30 g, 2.39 mmol, 1.0 equiv.) was dissolved in dry dichloromethane (24 mL), and 2-pyridinecarboxylic acid (503 mg, 4.06 mmol, 1.7 equiv.), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (778 mg, 4.06 mmol, 1.7 equiv.) and 4-dimethylaminopyridine (DMAP) (73 mg, 0.41 mmol, 0.17 equiv.) were added to the solution. The mixture was stirred at room temperature for 12 h. The mixture was extracted three times with ethyl acetate, and the organic layers were combined, washed once with water and once with saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The solution was purified by silica gel column chromatography (petroleum ether:ethyl acetate v / v = 4:1) to give compound 4 (1.55 g, 99% yield) as a white syrup.

[0167] Structural characterization of compound 4: [α]19.1D=+35.33 (c 0.24, CHCl3); 1 H NMR (400MHz, CDCl3) δ8.61(d,J=4.8Hz,1H,Ar),7.85(d,J=7.8Hz,1H,Ar),7.75-7.63(m,4H,Ar),7.46-7.33(m,4H,Ar),7.29-7.08(m,11H,Ar),4 .74-4.41(m,8H),4.33(d,J=5.4Hz,1H),4.10-3.99(m,2H),3.74(d,J=10 .4Hz,1H),3.61(d,J=10.4Hz,1H),2.69-2.53(m,2H),1.22-1.13(m,3H). 13C NMR (101MHz, CDCl3) δ164.6,149.9,147.7,137.8,137.75,136.74,135.67, 133.3,133.0,128.41,128.37,128.1,127.9,127.80,127.78,127.7,126.7 ,126.5,126.0,125.9,125.8,125.2,93.8,89.9,83.8,77.7,77.5,77.2,76 .9,76.8,73.7,73.3,72.6,70.8,64.9,22.5,15.0.HRMS(ESI+)m / z:[M+Na] + Calcd for C 39 H 39 NO6SNa 672.2390,Found 672.2398.

[0168] 2. Synthesis and characterization of compound 7:

[0169]

[0170] Compound 4 (650 mg, 0.99 mmol) and compound 3 (713 mg, 0.67 mmol) were dissolved in a dry dichloromethane (40 mL) solution, and then dry dichloromethane was added. Molecular sieve (1.9 g) was used to stir the resulting mixture under an argon atmosphere at room temperature for 30 min. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (283 mg, 0.99 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. After the reaction was monitored, it was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate volume ratio = 4:1 to 3:1) to give compound 6 (921 mg, yield 83%).

[0171] Compound 6 (921 mg, 0.55 mmol) and anhydrous copper acetate (150 mg, 0.83 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (28 mL, v / v, 20 / 1). The mixture was stirred at room temperature for 3 h. The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 5:1 to 3:1) to give a white, foamy compound 7 (752 mg, yield 85%).

[0172] Structural characterization of compound 7: [α]24.1D=+6.58 (c0.08, CHCl3);1 H NMR(400MHz, CDCl3)δ8.11(m,J=7.5Hz2H,Ar),7.91(t,J=6.8Hz,4H,Ar),7.84- 7.53(m,12H,Ar),7.48-7.27(m,8H,Ar),7.34-7.01(m,26H,Ar),6.11-6.04(m,3 H),5.89-5.87(m,1H),5.64(dd,J=9.7Hz,1H),5.30-5.09(m,1H),4.64(d,J=11. 7Hz,1H),4.57-4.32(m,8H),4.30-4.08(m,4H),3.94-3.21(m,7H),2.96(m,1H). 13 C NMR (101MHz, CDCl3) δ166.12,166.07,166.0,165.8,165.7,165.6,165.2,138.4,138.3,135.4,133.8,133.5,133.4,133.3,133.2,133 .2,133.1,130.3,130.02,129.99,129.9,129.9,129.8,129.8,129.7,129.2,129.1,129.02,128.99,128.9,128.8,128.50,128.48,12 8.42,128.38,128.3,128.2,128.05,127.98,127.80,127.76,127.7,127.6,126.4,126.2,126.0,125.7,105.3(C-2),104.4(C-2),90. 6,84.7,81.7,80.3,78.8,77.0,76.5,73.6,72.6,72.4,72.3,71.7,70.2,69.3,69.0,64.45,64.35,62.3,61.9.HRMS(ESI+)m / z:[M+Na] + Calcd for C 92 H 80 O 23 Na 1575.4983, Found 1575.4978.

[0173] 3. Synthesis and characterization of compound 9

[0174]

[0175] Compound 7 (728 mg, 0.47 mmol) and 4-dimethylaminopyridine (DMAP) (58 mg, 0.47 mmol) were dissolved in dry pyridine (2 mL), and benzoyl chloride (81 μL, 0.71 mmol) was added. The reaction was stirred at 50 °C for 2 h. The mixture was diluted with dichloromethane and washed successively with 1 M hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine. The organic phase was dried over anhydrous sodium sulfate, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate, v / v = 4:1) to give colorless syrup compound 8 (738 mg, yield 95%).

[0176] Compound 8 (738 mg, 0.45 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (205 mg, 0.90 mmol) were dissolved in dichloromethane / methanol (23 mL, v / v, 20 / 1). The resulting mixture was stirred at room temperature for 12 h. The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3.5:1) to give compound 9 (574 mg, yield 85%), a colorless syrup.

[0177] Structural characterization of compound 9: [α]19.8D=+9.72(c0.15,CHCl3); 1 H NMR (400MHz, CDCl3) δ8.12(d,J=7.7Hz,2H,Ar),7.95(d,J=7.7Hz,2H,Ar),7.88(dd,J=7.8,4 .6Hz,4H,Ar),7.80(d,J=7.8Hz,2H,Ar),7.71(m,6H,Ar),7.49(m,1H,Ar),7.45-6.99(m,35H ,Ar),6.14-5.93(m,4H),5.64(t,J=9.9Hz,1H),5.22(dd,J=10.3,3.7Hz,1H),4.70-4.16(m, 11H),4.15-3.92(m,4H),3.89-3.71(m,2H),3.53(d,J=12.5Hz,1H),3.26(d,J=12.6Hz,1H). 13CNMR(101MHz, CDCl3)δ166.2,166.0,165.9,165.8,165.8,165.5,165.4,165.3,164.99,164.96,138.2,137.6,133.7,1 33.4,133.2,133.0,132.9,132.8,130.2,129.9,129.8,129.7,129.6,129.53,129.48,129.07,128.8,128.7,128.4,12 8.3,128.25,128.18,128.1,127.9,127.8,127.7,127.6,127.60,127.56,127.5,105.2(C-2),104.5(C-2),90.2,85.7, 84.0,78.5,78.1,75.3,72.7,72.1,71.1,70.3,69.1,69.0,64.6,64.3,63.0,62.8,62.6,60.2.HRMS(ESI+)m / z:[M+Na] + Calcd for C 88 H 76 O 24 Na 1539.4619; Found 1539.4614.

[0178] 4. Synthesis and characterization of compound 11

[0179]

[0180] Compound 4 (369 mg, 0.56 mmol) and compound 9 (574 mg, 0.38 mmol) were dissolved in 15 mL of dry dichloromethane, and dried activated precipitate was added. Molecular sieve (1.5 g). The resulting mixture was stirred for 30 min at room temperature under an argon atmosphere. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (160 mg, 0.56 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. The reaction mixture was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 4:1 to 3:1) to give compound 10 (565 mg, yield 71%).

[0181] Compound 10 (565 mg, 0.27 mmol) and anhydrous copper acetate (73 mg, 0.40 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (14 mL, v / v = 20 / 1). The mixture was stirred at room temperature for 3 h, diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate, v / v = 3:1) to give compound 11 (534 mg, yield 99%) as a colorless syrup.

[0182] Structural characterization of compound 11: [α]25D = +16.29 (c 0.07, CHCl3); 1 H NMR (400MHz, CDCl3) δ8.11(d,J=7.4Hz,2H,Ar),7.93-7.81(m,8H,Ar),7.75-7.65(m,6H,Ar),7.64-7.54(m,4H,Ar),7.43(t ,J=7.3Hz,1H,Ar),7.40-7.20(m,15H,Ar),7.17-6.95(m,29H,Ar),6.95-6.84(m,2H,Ar),6.17-5.98(m,3H),5.87(t,J=6.3 Hz,1H),5.62(t,J=9.9Hz,1H),5.23(dd,J=10.3,3.5Hz,1H),4.75-4.55(m,6H),4.55-4.36(m,8H),4.31-4.09(m,9H),4.04 -3.93(m,2H),3.93-3.82(m,3H),3.69-3.55(d,J=9.3Hz,2H),3.48(d,J=10.5Hz,1H),3.38(d,J=10.4Hz,1H),3.21(s,1H). 13C NMR (101MHz, CDCl3) δ166.04,166.00,165.74,165.72,165.5,165.1,138 .6,138.2,137.9,135.2,133.6,133.4,133.3,133.1,132.94,132.88,130 .2,130.0,129.89,129.86,129.71,129.68,129.6,129.3,129.2,129.0,1 29.0,128.8,128.7,128.43,128.37,128.32,128.26,128.2,127.9,127.9 ,127.8,127.7,127.7,127.6,127.5,127.4,127.3,126.7,126.2,126.0,1 25.8,105.2(C-2),104.2(C-2),104.0(C-2),90.5,85.6,83.4,82.4,81.8 ,81.4,79.0,77.6,76.9,76.0,73.8,72.7,72.6,72.3,72.3,71.4,71.3,7 0.5,69.2,69.0,64.5,64.4,62.8,62.7,62.5.MS(Maldi-TOF)m / z:[M+Na] + Calcdfor C 119 H 106 O 29 Na 2021.6712; Found 2021.6715.

[0183] 5. Synthesis and characterization of compounds 14 and 15

[0184]

[0185] Compound 5 (177 mg, 0.30 mmol, glycosyl donor) and compound 7 (303 mg, 0.20 mmol, glycosyl acceptor) were dissolved in 12 mL of dry dichloromethane, and dried activated glycosyl was added. Molecular sieve (1.0 g). The resulting mixture was stirred for 30 min at room temperature under an argon atmosphere. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (160 mg, 0.56 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. The reaction mixture was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3.5:1) to give compound 12 (305 mg, yield 74%).

[0186] Compound 12 (305 mg, 0.15 mmol) and anhydrous copper acetate (40 mg, 0.22 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (7.3 mL, v / v 20 / 1). The mixture was stirred at room temperature for 3 h, diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3 / 1) to give compound 14 (286 mg, yield 99%) as a white solid.

[0187] Structural characterization of compound 14: [α]22.4D=+7.42(c 0.11,CHCl3); 1 H NMR(400MHz, CDCl3)δ8.16(d,J=7.6Hz,2H,Ar),7.91(d,J=7.8Hz,2H,Ar),7.87-7.81(m,4H,Ar),7.78-7.7 1(m,6H,Ar),7.68-7.48(m,4H,Ar),7.40-6.93(m,50H,Ar),6.19-6.03(m,3H),5.90(t,J=6.6Hz,1H),5.66( t,J=10.0Hz,1H),5.31(dd,J=10.4,3.6Hz,1H),4.72-4.26(m,20H),4.17-4.13(m,2H),3.99-3.85(m,4H),3 .56-3.45(m,4H),3.53-3.48(m,2H),3.31(d,J=10.6Hz,1H),3.11(d,J=10.6Hz,1H),2.90(t,J=6.5Hz,1H). 13C NMR (101MHz, CDCl3) δ166.1,166.1,165.7,165.6,165.2,138.5,138.4,138.3 ,138.2,135.5,133.5,133.4,133.3,133.10,133.06,133.01,132.96,130.4,1 30.1, 130.0, 129.9, 129.8, 129.72, 129.68, 129.5, 129.3, 129.2, 129.03, 128.97, 128.9, 128.4, 128.42, 128.39, 128.34, 128.32, 128.2, 128.05, 128.01, 12 7.8,127.71,127.67,127.59,127.56,127.5,126.5,126.1,125.9,125.8,105 .4(C-2),104.8(C-2),104.3(C-2),90.9,84.9,84.4,82.0,80.1,80.0,78.8,7 7.6,77.2,77.2,76.9,76.8,73.6,73.6,72.6,72.6,72.5,72.4,71.9,71.4,71 .0,70.6,69.3,69.2,64.4,63.2,62.8,62.6,62.2.MS(Maldi-TOF)m / z:[M+Na] + Calcdfor C 119 H 108 O 28 Na 2007.6919; Found 2007.6911.

[0188] Compound 5 (215 mg, 0.36 mmol, glycosyl donor) and compound 11 (480 mg, 0.24 mmol, glycosyl acceptor) were dissolved in a dry dichloromethane (10 mL) solution, and freshly activated [material / material] was added. Molecular sieve (1.5 g). The resulting mixture was stirred for 30 min at room temperature under an argon atmosphere. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (103 mg, 0.36 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. The reaction mixture was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 4:1 to 3:1) to give compound 13 (443 mg, yield 72%).

[0189] Compound 13 (443 mg, 0.17 mmol) and anhydrous copper acetate (47 mg, 0.26 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (9 mL, v / v = 20 / 1). The mixture was stirred at room temperature for 3 h. The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3.5:1) to give compound 15 (392 mg, yield 94%) as a white syrup.

[0190] Structural characterization of compound 15: [α]20D = -5.37 (c 0.19, CHCl3); 1 H NMR(400MHz, CDCl3) δ8.07(d,J=7.7Hz,2H,Ar),7.91(d,J=7.7Hz,2H,Ar),7.88-7.76(m ,6H,Ar),7.75-7.66(m,5H,Ar),7.63-7.51(m,4H,Ar),7.36-6.91(m,63H),6.25-6.01( m,3H),5.94-5.91(m,1H),5.67(t,J=10.1Hz,1H),5.27(d,J=10.5Hz,1H),4.75(d,J=11 .8Hz,1H),4.62-4.52(m,7H),4.46-4.02(m,25H),3.96-3.71(m,7H),3.62-3.34(m,6H). 13C NMR (101MHz, CDCl3) δ166.0,166.0,165.9,165.7,165.6,165.6,165.5,165.1,138.5,1 38.4,138.33,138.30,138.2,138.0,137.8,135.3,133.5,133.33,133.26,133.2,133. 1,133.0,132.9,130.2,130.0,129.9,129.8,129.7,129.6,129.3,129.2,128.98,128.95,128.8,128.4,128.3,128.30,128.26,128.23,128.20,128.0,127.91,127.87,127.8 ,127.7,127.64,127.58,127.5,127.44,127.38,126.6,126.1,125.9,125.8,105.2(C- 2),104.6(C-2),104.1(C-2),90.6,85.2,85.0,84.9,84.2,83.2,82.0,80.2,80.0,78. 3,77.4,77.3,76.8,75.8,73.7,73.5,72.5,72.44,72.39,72.1,72.0,71.7,71.4,71.3 ,70.5,69.1,69.0,64.6,64.4,63.8,63.2,62.9,62.4,62.2.MS(Maldi-TOF)m / z:[M+Na] + Calcd for C 147 H 138 O 34 Na 2469.8962; Found 2469.8960.

[0191] 6. Synthesis and characterization of compounds 22 and 23

[0192]

[0193] Compound 5 (118 mg, 0.20 mmol, glycosyl donor) and compound 14 (260 mg, 0.13 mmol, glycosyl acceptor) were dissolved in a dry dichloromethane solution (8 mL), and freshly activated [material / material] was added. Molecular sieve (0.5 g). The resulting mixture was stirred for 30 min at room temperature under an argon atmosphere. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (103 mg, 0.36 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. The reaction mixture was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3:1 to 2.5:1) to give compound 16 (240 mg, yield 73%).

[0194] Compound 16 (150 mg, 0.0595 mmol) and anhydrous copper acetate (16 mg, 0.0892 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (3 mL, v / v = 20 / 1). The mixture was stirred at room temperature for 5 h. The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 5:1 to 3:1) to give compound 18 (133 mg, yield 93%).

[0195] Compound 18 (133 mg, 0.055 mmol) and 4-dimethylaminopyridine (DMAP) (7 mg, 0.055 mmol) were dissolved in dry pyridine (1 mL), and benzoyl chloride (10 μL, 0.0825 mmol) was added. The mixture was stirred at 50 °C for 2 h. The solution was diluted with ethyl acetate and washed successively with 1 M hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine. The organic phase was dried over anhydrous sodium sulfate, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate volume ratio = 10:1 to 2.5:1) to give colorless syrup compound 20 (126 mg, yield 91%).

[0196] Compound 20 (126 mg, 0.05 mmol) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) (17 mg, 0.075 mmol) were dissolved in dichloromethane / methanol (2.5 mL, v / v = 20 / 1). The resulting mixture was stirred at room temperature for 12 h. The solution was diluted with ethyl acetate, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3:1) to give colorless syrup compound 22 (101 mg, yield 85%).

[0197] Structural characterization of compound 22: [α]20.4D=-12.49(c 0.11,CHCl3); 1H NMR(400MHz,CDCl3)δ8.01(d,J=7.7Hz,2H,Ar),7.88-7.82(m,8H,Ar),7.76-7.59(m,6H,Ar),7.46-7.44(m,1H,Ar),7.32(m,8H,Ar),7.21-7.02(m,55H,Ar),6.09-5.99(m,3H),5.79(d,J=5.4Hz,1H),5.55-5.50(m,1H),5.05-5.03(m,1H),4.77-4.54(m,6H),4.48-4.22(m,20H),4.09-3.86(m,10H),3.79-3.49(m,8H),3.32(d,J=12.0Hz,1H),3.13(d,J=12.3Hz,1H). 13 C NMR(101MHz,CDCl3)δ166.2,166.1,166.0,165.8,165.7,165.50,165.47,165.2,138.5,138.4,138.3,138.1,138.0,137.9,133.54,133.48,133.3,133.2,133.11,133.07,132.95,130.30,130.05,130.00,129.9,129.80,129.76,129.7,129.6,129.3,129.2,129.05,128.97,128.9,128.8,128.5,128.45,128.43,128.41,128.35,128.31,128.27,127.83,127.78,127.76,127.6,127.5,127.4,105.81(C-2),104.77(C-2),104.6(C-2),104.3(C-2),91.0,85.2,84.6,84.3,83.3,83.2,82.8,79.6,79.0,78.9,77.6,77.0,73.6,73.5,72.7,72.6,72.5,72.5,72.4,72.11,72.05,71.6,70.3,69.2,68.9,64.8,64.6,63.2,63.0,62.8,62.6.MS(Maldi-TOF)m / z:[M+Na] + Calcd for C 142 H 132 O 34 Na 2403.8492;Found 2403.8491.

[0198] Compounds 5 (144 mg, 0.24 mmol, glycosyl donor) and 15 (392 mg, 0.16 mmol, glycosyl acceptor) were dissolved in a dry dichloromethane (40 mL) solution, and freshly activated... MS (1.5 g). The resulting mixture was stirred for 30 min at room temperature under an argon atmosphere. Then, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (70 mg, 0.24 mmol) was added, and the mixture was stirred at -20 °C for 2.5 h. The reaction mixture was quenched with triethylamine (2 mL). The mixture was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3:1 to 2.5:1) to give compound 17 (350 mg, yield 74%).

[0199] Compound 17 (350 mg, 0.12 mmol) and anhydrous copper acetate (32 mg, 0.17 mmol) were added to a round-bottom flask and dissolved in dichloromethane / methanol (6 mL, v / v = 20 / 1). The mixture was stirred at room temperature for 3 h. The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 5:1 to 3:1) to give compound 19 (307 mg, yield 91%).

[0200] Compound 19 (307 mg, 0.11 mmol) and 4-dimethylaminopyridine (DMAP) (4 mg, 0.03 mmol) were dissolved in dry pyridine (0.5 mL), and benzoyl chloride (25 μL, 0.22 mmol) was added. The mixture was stirred at 50 °C for 2 h. The solution was diluted with ethyl acetate and washed successively with 1 M hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated brine. The organic phase was dried over anhydrous sodium sulfate, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate volume ratio = 10:1 to 2.5:1) to give colorless syrup compound 21 (279 mg, yield 88%).

[0201] Sugar compound 21 (100 mg, 0.03 mmol) and DDQ (15 mg, 0.06 mmol) were dissolved in dichloromethane / methanol (1.7 mL, v / v = 20 / 1), and the resulting mixture was stirred at room temperature for 12 h. The solution was diluted with ethyl acetate, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered under vacuum and concentrated, and purified by column chromatography (petroleum ether:ethyl acetate v / v = 3:1) to give a pale yellow syrup compound 23 (85 mg, yield 85%).

[0202] Structural characterization of compound 23: [α]24.4D=-5.97 (c 0.06, CHCl3);1 H NMR(400MHz,CDCl3)δ8.04-7.66(m,20H,Ar),7.47-6.86(m,75H,Ar),6.16-6.07(m,2H),5.97(d,J=3.9Hz,1H),5.92(t,J=7.6Hz,1H),5.67(t,J=9.9Hz,1H),5.30-5.18(m,1H),4.68-4.27(m,25H),4.24-3.96(m,14H),3.94-3.59(m,14H),3.50-3.40(m,4H). 13C NMR(201MHz,CDCl3)δ166.3,166.2,166.1,165.88,165.87,165.7,165.6,165.5,165.2,138.49,138.47,138.41,138.37,138.3,138.2,138.13,138.11,138.0,137.8,137.8,133.7,133.6,133.40,133.35,133.3,133.1,133.02,133.00,132.96,130.3,130.2,130.1,130.03,129.99,129.96,129.9,129.91,129.89,129.8,129.82,129.79,129.3,129.11,129.09,129.07,128.92,128.89,128.8,128.6,128.52,128.49,128.46,128.45,128.42,128.39,128.37,128.35,128.34,128.32,128.3,128.2,128.2,128.21,128.16,128.1,128.1,128.0,127.91,127.89,127.86,127.83,127.81,127.79,127.73,127.70,127.68,127.66,127.64,127.60,127.56,127.53,127.51,127.48,105.2(C-2),105.1(C-2),104.7(C-2),104.6(C-2),104.5(C-2),90.6,85.8,85.3,84.5,84.1,83.7,83.4,82.9,82.7,79.3,79.0,78.2,76.9,76.3,75.6,73.63,73.55,73.4,72.81,72.75,72.7,72.65,72.57,72.53,72.46,72.4,72.42,72.35,72.20,72.16,72.1,72.0,71.2,70.5,69.10,69.07,64.7,64.41,64.38,64.3,64.1,63.4,63.22,63.15,62.3.MS(Maldi-TOF)m / z:[M+Na] + Calcd for C 169 H 158 O 40 Na2850.0222;Found2850.0229.

[0203] 7. Synthesis and characterization of compounds 24 and 25

[0204]

[0205] Compound 22 (50 mg, 0.017 mmol, 1.0 equiv, glycosyl acceptor), the promoter 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (30 mg, 0.105 mmol, 5 equiv), and freshly activated [unspecified ingredient] were added to a round-bottom flask dried in an oven. Molecular sieve (200 mg). Under argon protection, anhydrous toluene (1.5 mL) (concentration: 0.05 M, calculated as a compound) was added, and the mixture was stirred at -78 °C for 1 h. Simultaneously, compound 5 (63 mg, 0.105 mmol, 5 equiv, glycosyl donor) was dissolved in anhydrous toluene (0.6 mL) and slowly added dropwise to a round-bottom flask for reaction. The reaction flask was then heated to -35 °C. After stirring at -35 °C for 24 h, the mixture was filtered. Molecular sieves were used, and the filtrate was quenched with triethylamine (1 mL). The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate volume ratio = 2.5:1 to 2:1) to give a pale yellow syrup compound 24 (37 mg, yield 60%).

[0206] Structural characterization of compound 24: [α]24.5D = -17.20 (c 0.05, CHCl3); 1 H NMR(400MHz, CDCl3)δ8.51(d,J=4.8Hz,1H,Ar),8.08(d,J=7.7Hz,2H,Ar),7.89-7 .71(m,12H,Ar),7.62(d,J=7.9Hz,1H,Ar),7.46-6.92(m,84H,Ar),6.19-6.07(m, 2H),6.02(d,J=3.8Hz,1H),5.79(t,J=5.6Hz,1H),5.55(t,J=9.9Hz,1H),5.11(dd ,J=10.3,3.7Hz,1H),4.75-4.22(m,35H),4.15-3.90(m,12H),3.77-3.27(m,11H). 13C NMR(151MHz,CDCl3)δ166.1,165.6,165.59,165.55,165.5,165.2,164.7,164.6,150.0,149.9,149.8,147.8,147.6,138.7,138.52,138.47,138.4,138.4,138.33,138.29,138.11,138.00,137.95,137.9,137.01,136.96,133.4,133.3,133.2,133.10,133.06,132.9,130.3,130.09,130.05,130.0,129.9,129.78,129.75,129.6,129.5,129.4,129.12,129.00,128.99,128.8,128.5,128.4,128.4,128.38,128.36,128.33,128.31,128.3,128.2,128.2,128.1,128.0,127.8,127.80,127.76,127.71,127.67,127.6,127.60,127.58,127.56,127.53,127.51,127.50,127.47,127.41,127.39,127.36,127.3,126.9,126.8,125.45,125.39,125.2,106.0(C-2),104.74(C-2),104.67(C-2),104.6(C-2),103.8(C-2),91.0,84.4,84.3,84.0,83.9,83.5,83.0,82.8,79.4,79.0,78.6,77.8,77.59,73.58,73.52,73.51,73.49,73.3,72.6,72.5,72.51,72.48,72.44,72.36,72.3,72.1,72.0,71.4,71.2,70.6,69.2,68.8,65.9,65.2,64.4,63.6,63.0,62.7,62.6.MS(Maldi-TOF)m / z:[M+K] + CalcdforC 175 H 163 NO 40 Na2941.0644;Found2941.0642.

[0207] Synthesis of Compound 25: Compound 23 (50 mg, 0.017 mmol, glycosyl acceptor), the promoter 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) (25 mg, 0.085 mmol), and freshly activated [unspecified ingredient] were added to an oven-dried round-bottom flask. Molecular sieve (200 mg). Under argon protection, anhydrous toluene (2 mL) (concentration: 0.05 M, calculated based on glycosyl donor compound 5) was added, and the mixture was stirred at -78 °C for 1 h. Simultaneously, compound 5 (51 mg, 0.085 mmol) was dissolved in anhydrous toluene (1.5 mL) and slowly added dropwise to a round-bottom flask for the reaction, and the reaction flask was heated to -35 °C. After stirring at -35 °C for 24 h, the mixture was filtered. Molecular sieves were used, and the filtrate was quenched with triethylamine (1 mL). The solution was diluted with dichloromethane, washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and purified by column chromatography (petroleum ether:ethyl acetate volume ratio = 2.5:1 to 2:1) to give compound 25 (36 mg, yield 61%) as a pale yellow solid.

[0208] Structural characterization of compound 25: [α]25D = -8.89 (c 0.09, CHCl3); 1 H NMR (400MHz, CDCl) 3) δ8.54(d,J=4.6Hz,1H,Ar),8.10-7.62(m,21H,Ar),7.52-6.88(m,92H,Ar),6 .14(d,J=7.6Hz,1H),6.10-6.03(m,2H),5.95(t,J=7.7Hz,1H),5.66(t,J=10. 1Hz,1H),5.24-5.21(m,1H),4.78(d,J=12.0Hz,1H),4.70(d,J=12.0Hz,1H),4 .63-4.21(m,34H),4.18-4.07(m,8H),4.04-3.79(m,17H),3.58-3.42(m,6H). 13C NMR(201MHz,CDCl3)δ166.2,166.09,166.07,166.0,165.8,165.71,165.68,165.62,165.55,165.1,164.7,149.99,149.97,147.6,138.83,138.76,138.74,138.69,138.6,138.5,138.41,138.35,138.23,138.16,138.15,138.1,138.0,138.02,137.97,137.94,137.89,137.1,133.5,133.32,133.29,133.1,133.04,132.98,132.95,130.2,130.02,129.98,129.97,129.91,129.86,129.80,129.75,129.3,129.2,129.1,129.0,128.9,128.8,128.52,128.47,128.45,128.42,128.40,128.39,128.36,128.33,128.28,128.26,128.23,128.21,128.17,128.1,128.05,128.01,127.91,127.89,127.87,127.82,127.78,127.76,127.7,127.70,127.68,127.66,127.65,127.61,127.58,127.56,127.53,127.50,127.47,127.45,127.38,127.36,127.34,127.29,126.9,125.4,105.1(C-2),104.86(C-2),104.82(C-2),104.73(C-2),104.65(C-2),104.2(C-2),90.6,85.2,84.6,84.2,84.0,83.8,83.7,83.5,83.4,83.0,79.3,79.1,77.6,77.5,77.4,77.3,77.25,77.16,77.1,77.0,76.7,75.4,73.5,73.51,73.47,73.4,73.3,72.60,72.55,72.49,72.47,72.4,72.3,72.18,72.15,72.1,72.0,71.9,71.3,70.5,70.5,69.0,65.5,64.9,64.5,64.2,64.1,63.8,63.6,63.29,62.26.MS(Maldi-TOF)m / z:[M+Na]. + Calcd for C 202 H 189 NO 46 Na 3387.2373; Found 3387.2372.

[0209] 8. Synthesis and characterization of Achyranthes bidentata polysaccharide ABW90-1 (compound 1) and Achyranthes bidentata polysaccharide ABW50-1 (compound 2):

[0210]

[0211] Synthesis of Achyranthes bidentata polysaccharide ABW90-1: Compound 24 (37 mg, 0.013 mmol) was dissolved in dichloromethane / methanol (1 mL, v / v, 1:1), and sodium methoxide was added to adjust the pH to 11. After stirring at room temperature for 48 h, the solution was neutralized to pH 7 with 3 M hydrochloric acid, and the mixture was filtered and concentrated. The residue was purified by silica gel column chromatography (MeOH:DCM v / v = 10:1) to give compound 26 (25 mg). Compound 26 (25 mg, 0.013 mmol) and Pd / C (240 mg, 10%) were added to THF / MeOH / H2O (0.48 mL / 2.42 mL / 0.25 mL). The air in the reaction flask was replaced by a double-row tube, and the mixture was stirred for 24 h at room temperature under H2 atmosphere. After filtration, the resulting liquid fraction was concentrated under vacuum and purified by Sephadex™ LH-20 gel column chromatography (water / methanol, v / v = 1 / 1) to obtain the final product, colorless syrup Achyranthes bidentata polysaccharide ABW90-1 (11 mg, overall yield of the two-step reaction was 88%).

[0212] Structural characterization of Achyranthes bidentata polysaccharide ABW90-1: [α]23.5D=-8.32(c 0.05,H2O); 1 H NMR (800MHz, D2O) δ5.33 (d, J = 3.7Hz, 1H), 4.21-4.06 (m, 5H), 4.05-3.92 (m, 5H), 3.90-3.71 (m, 14H), 3.69-3.51 (m, 13H), 3.49-3.35 (m, 4H). 13C NMR(201MHz,D2O)δ104.1(C-2),103.7(C-2),103.6(C-2),103.23(C-2),1 03.18(C-2),92.5,81.2,81.1,80.9,80.3,80.2,77.0,76.6,76.5,76.41,7 6.38,75.40,74.8,74.5,74.1,73.7,72.5,72.4,71.0,69.1,63.4,63.1,62 .4,62.1,62.0,60.9,60.8,60.4,60.0,59.9,59.7.HRMS(ESI+)m / z:[M+Na] + CalcdforC 36 H 62 O 31 Na 1013.3167; Found 1013.3176.

[0213] Synthesis of Achyranthes bidentata polysaccharide ABW50-1: Compound 25 (30 mg, 0.009 mmol) was dissolved in dichloromethane / methanol (1 mL, v / v, 1:1), and sodium methoxide was added to adjust the pH to 11. After stirring at room temperature for 48 h, the solution was neutralized to pH 7 with 3 M hydrochloric acid, and the mixture was filtered and concentrated. The residue was purified by silica gel column chromatography (MeOH:DCM = 10:1) to give compound 27 (19 mg). Compound 27 (19 mg, 0.008 mmol) and Pd / C (180 mg, 10%) were added to THF / MeOH / H2O (0.3 mL / 1.5 mL / 0.15 mL). The air in the reaction flask was replaced by a double-row tube, and the mixture was stirred for 24 h at room temperature under H2 atmosphere. After filtration, the resulting liquid fraction was concentrated under vacuum and purified by Sephadex™ LH-20 gel column (water / methanol, v / v = 1 / 1) to obtain the final product, Achyranthes bidentata polysaccharide ABW50-1 (9 mg, overall yield of the two-step reaction was 87%).

[0214] Structural characterization of Achyranthes bidentata polysaccharide ABW50-1: [α]23.8D=-10.13(c 0.11,H2O); 1 H NMR(800MHz,D2O)δ5.35(d,J=3.7Hz,1H),4.22-4.06(m,6H),4.06-3.92(m, 6H),3.92-3.82(m,4H),3.66(m,26H),3.52-3.43(m,3H),3.42-3.34(m,2H). 13 CNMR (201MHz, D2O) 13C NMR(201MHz,D2O)δ104.2(C-2),103.7(C-2),103.6(C-2),103.3(C-2),103.2(C-2), 103.0(C-2),92.5,81.2,81.1,81.0,80.9,80.3,80.25,77.16,77.0,76.8,76.7,76.4 ,76.3,75.4,74.8,74.5,74.3,74.1,73.8,72.6,72.4,71.1,69.2,63.4,63.2,62.4, 62.2,62.1,62.0,61.0,60.7,60.6,60.4,60.05,59.95,59.7.HRMS(ESI+)m / z:[M+Na] + Calcdfor C 42 H 72 O 36 Na 1175.3695; Found1175.3711.

[0215] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for synthesizing Achyranthes bidentata polysaccharide ABW90-1 and / or Achyranthes bidentata polysaccharide ABW50-1, comprising the following steps: Compounds 3 and 4 were subjected to a first glycosylation reaction to form a β-(2→1)-D-fructofuranosyl bond, yielding compound 6; Compound 6 was subjected to a first depico protecting group reaction to obtain compound 7; The C6-OH of the terminal sugar of compound 7 was subjected to a first Bz protecting group introduction reaction to give compound 8; Compound 8 was subjected to a first deprotection reaction to obtain compound 9; Compound 9 and compound 4 were subjected to a second glycosylation reaction to form a β-(2→1)-D-fructofuranosyl glycosidic bond to obtain compound 10; Compound 10 was subjected to a second depico protecting group reaction to obtain compound 11; Compound 7 or compound 11 is subjected to a third glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 12 or compound 13; Compound 12 or 13 is subjected to a third depico protecting group reaction to obtain compound 14 or 15. Compound 14 or 15 is subjected to a fourth glycosylation reaction with compound 5 to form a β-(2→6)-D-fructofuranosyl glycosidic bond, yielding compound 16 or 17. Compound 16 or 17 is subjected to a fourth depico protecting group reaction to obtain compound 18 or 19. A second Bz protecting group introduction reaction is carried out at the C6-OH of the terminal sugar of compound 18 or compound 19 to give compound 20 or compound 21. Compound 20 or compound 21 is subjected to a second deprotection reaction to obtain compound 22 or compound 23; Compound 22 or 23 is subjected to a fifth glycosylation reaction with compound 5 to form a β-(2→1)-D-fructofuranosyl glycosidic bond, yielding compound 24 or 25. Compound 24 or 25 is subjected to a benzoyl group removal and Pico protecting group removal reaction to obtain compound 26 or 27; The compound 26 or compound 27 was subjected to a debenzyl protecting group reaction to obtain Achyranthes bidentata polysaccharide ABW90-1 or Achyranthes bidentata polysaccharide ABW50-1; The first, second, third, fourth, and fifth glycosylation reactions are all carried out in the presence of a first solvent, which includes one or more of toluene, dichloromethane, dichloroethane, and acetonitrile; the temperatures of the first, second, third, and fourth glycosylation reactions are independently -25 to -15°C, and the temperature of the fifth glycosylation reaction is -78°C to -35°C; 。 2. The synthesis method according to claim 1, characterized in that, The first, second, third, fourth, and fifth glycosylation reactions were all carried out in the presence of an accelerator and an additive. The accelerator includes one or more of N-iodosuccinimide, N-bromosuccinimide, trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonic acid ester, and dibromohydantoin; The additive includes a 4Å molecular sieve.

3. The synthesis method according to claim 1, characterized in that, The first, second, third, and fourth depico protecting group reactions were all carried out in the presence of the depico reagent and the second solvent. The depico-removing reagent includes Cu(OAc)2; The second solvent includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform.

4. The synthesis method according to claim 1, characterized in that, Both the first and second reactions of introducing Bz protecting groups are carried out in the presence of Bz protecting group reagents, organic bases and a third solvent. The Bz protecting group reaction reagents include benzoyl chloride and / or benzoic anhydride; The organic base includes one or more of triethylamine, 2,6-dimethylpyridine, diisopropylethylamine and pyridine; The third solvent includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine.

5. The synthesis method according to claim 1, characterized in that, Both the first and second deNap protecting group removal reactions were carried out in the presence of the deNap reagent and the fourth solvent. The deNap-removing reagent includes 2,3-dichloro-5,6-dicyanobenzoquinone; The fourth solvent includes one or more of dichloromethane, methanol, dichloroethane, ethanol, isopropanol, and chloroform.

6. The synthesis method according to claim 1, characterized in that, The debenzoyl and Pico protecting group reactions are carried out in the presence of a deprotecting reagent and a fifth solvent; The deprotection reagent includes one or more of alkali metal alkoxides, alkali metal hydroxides, and alkali metal carbonates; The fifth solvent includes a mixed solvent of dichloromethane and methanol, a mixed solvent of dichloroethane and ethanol, or isopropanol.

7. The synthesis method according to claim 1, characterized in that, The debenzyl protecting group reaction is carried out in the presence of the debenzyl protecting reagent and the sixth solvent; The debenzyl protecting agent comprises a palladium compound and hydrogen gas, wherein the palladium compound comprises palladium on carbon and / or palladium hydroxide, and the hydrogen gas is at a pressure of 1~30 atm; The sixth solvent includes one or more of methanol, ethanol, tetrahydrofuran, water, isopropanol, and ethyl acetate; The reaction temperature for the debenzylation protecting group reaction is 25~60℃.

8. The synthesis method according to claim 1, characterized in that, The synthesis of compound 4 includes the following steps: Compound M1 was subjected to a reaction to introduce a Nap protecting group into its Cl-OH group, yielding compound M2; Compound M2 was subjected to a deprotection reaction to obtain compound M3; The C6-OH of compound M3 was subjected to a Pico protecting group introduction reaction to obtain compound 4; 。 9. The synthesis method according to claim 8, characterized in that, The Nap protecting group introduction reaction is carried out in the presence of Nap protecting group reaction reagent, basic reagent and seventh solvent; The Nap protecting group reaction reagent includes 2-chloromethylnaphthalene or 2-bromomethylnaphthalene; The alkaline reagent includes one or more of the following: triethylamine, 2,6-dimethylpyridine, diisopropylethylamine, pyridine, potassium carbonate, sodium hydride, cesium carbonate, sodium hydroxide, potassium tert-butoxide, potassium hydroxide, and potassium phosphate. The seventh solvent includes one or more of dichloromethane, tetrahydrofuran, triethylamine, acetonitrile, pyridine, diisopropylethylamine, and 2,6-dimethylpyridine.

10. The synthesis method according to claim 8, characterized in that, The TBDPS removal reaction is carried out in the presence of a TBDPS removal reagent and an eighth solvent; the TBDPS removal reagent includes 3HF·Et3N, HF·Pyridine, TBAF, TBAF / AcOH, or KF; the eighth solvent includes tetrahydrofuran and / or toluene; The Pico protecting group introduction reaction is carried out in the presence of a Pico protecting group reaction reagent, a condensation reagent, a basic reagent, and a ninth solvent; the Pico protecting group reaction reagent includes 2-pyridinecarboxylic acid; the condensation reagent includes one or more of 1-ethyl-3-(3-dimethylpropylamine)carbodiimide, dicyclohexylcarbodiimide, diisopropylcarbodiimide, O-benzotriazole-N,N,N',N'-tetramethylurea tetrafluoroboronic acid, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate, and O-benzotriazole-tetramethylurea hexafluorophosphate; the basic reagent includes one or more of 4-dimethylaminopyridine, diisopropylethylamine, and triethylamine; and the ninth solvent includes one or more of dichloromethane, tetrahydrofuran, and toluene.

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