Four acinetobacter baumannii cell wall oligosaccharide fragments as well as synthesis method and application thereof

Abstract

The invention belongs to the field of chemical synthesis, and particularly relates to four acinetobacter baumannii cell wall oligosaccharide fragments as well as a synthesis method and application thereof. Four acinetobacter baumannii core oligosaccharide fragments are synthesized by adopting a divergent synthesis strategy, compounds 1-3 take orthogonally protected alpha-(2-> 5)-Kdo-Kdo disaccharide as key precursors, protecting groups at different sites are selectively removed, glycosyl is introduced through a stereoselective glycosylation reaction, and thus a target molecular skeleton is constructed. The method disclosed by the invention and the four finally prepared acinetobacter baumannii core oligosaccharide fragments have huge industrial application potential.

Description

Priority application

[0001] This application claims priority to the Chinese invention patent application [CN2024112241869] filed on September 2, 2024, "Four types of Acinetobacter baumannii cell wall oligosaccharide fragments, their synthesis methods and applications", which is incorporated by reference in its entirety. Technical Field

[0002] The invention belongs to the field of chemical synthesis, and specifically relates to four Acinetobacter baumannii cell wall oligosaccharide fragments and a synthesis method and application thereof. Background Art

[0003] Acinetobacter baumannii is a non-fermenting Gram-negative bacterium that is one of the pathogens causing serious nosocomial infections. The bacterium is widely distributed in nature (e.g., water, soil) and on human skin. Its infection characteristics include: (1) Acinetobacter baumannii pneumonia accounts for 5%-10% of ventilator-associated pneumonia (VAP); (2) About 20% of infections in intensive care units worldwide are caused by Acinetobacter baumannii; (3) The mortality rate of ICU patients with Acinetobacter baumannii bloodstream infection is greater than 35%; (4) The mortality rate of Acinetobacter baumannii meningitis after craniotomy is as high as 70%; (5) Acinetobacter baumannii causes about 2.1% of ICU skin and soft tissue infections; (6) The mixed infection rate of Acinetobacter baumannii is about 60%, and it is often mixed with Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacter. At present, the clinical treatment of Acinetobacter baumannii infection mainly relies on antibiotics or combined medications, but with the overuse of antibiotics, the risk of outbreaks of multidrug-resistant, extensively drug-resistant, and pan-drug-resistant strains has increased. Therefore, there is an urgent need to develop new antimicrobial drugs or antimicrobial vaccines.

[0004] The publication number is CN116970010A (20231031), and the invention name is a patent for four core oligosaccharide fragments of Acinetobacter baumannii lipopolysaccharide and a method for synthesizing the same, which discloses four core oligosaccharide fragments of Acinetobacter baumannii lipopolysaccharide, but the oligosaccharide fragments of these lipopolysaccharides have different sugar sequences from the cell wall oligosaccharide fragments of Acinetobacter baumannii. There is no report on the synthesis of cell wall oligosaccharide fragments of Acinetobacter baumannii in the existing literature.

[0005] In summary, new synthetic technologies are urgently needed to prepare A. baumannii cell wall oligosaccharide fragments to make up for the shortcomings of existing technologies. Summary of the invention

[0006] In view of this, the object of the present invention is to provide four Acinetobacter baumannii cell wall oligosaccharide fragments and their preparation methods and related applications. The specific technical scheme is as follows.

[0007] In one aspect, the present invention provides four kinds of cell wall oligosaccharide fragments of Acinetobacter baumannii, including the structures shown in formula (1), formula (2), formula (3) or formula (4):

[0008]

[0009] Among the above four cell wall oligosaccharide fragments of Acinetobacter baumannii, compounds 1-3 all contain alpha-(2→5) linked Kdo-Kdo disaccharide fragments; compounds 3 and 4 both have 4,7-branched Kdo skeletons.

[0010] The ends of the above four types of Acinetobacter baumannii cell wall oligosaccharide fragments are all connected to a short chain with an amino group, which can be used for conjugation with carrier proteins.

[0011] In another aspect, the present invention further provides methods for synthesizing the above four types of Acinetobacter baumannii cell wall oligosaccharide fragments, which are specifically as follows.

[0012] A method for preparing an oligosaccharide fragment of a cell wall of Acinetobacter baumannii comprises the following steps:

[0013] S01: Compound 7 is used as a starting material, and compound 8 is subjected to a glycosylation reaction to obtain compound 6; the glycosylation reaction is to place compound 7 and compound 8 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0014] As a preferred embodiment, the acidic reagent selected is trifluoromethanesulfonic acid.

[0015] S02: dissolving the compound 6 in dry tetrahydrofuran, and then mixing with a desiliconizing agent to obtain a compound 9 through a desiliconization reaction; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid or tetrabutylammonium fluoride;

[0016] As a preferred embodiment, the desiliconization reagent is triethylamine trihydrofluoric acid; the reaction conditions are room temperature;

[0017] S03: Compound 9 and Compound 10 are subjected to a glycosylation reaction to obtain Compound 11; the glycosylation reaction is to place Compound 9 and Compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0018] As a preferred embodiment, the acidic reagent is trimethylsilyl trifluoromethanesulfonate;

[0019] S04: The compound 11 is sequentially subjected to acid hydrolysis reaction, alkaline hydrolysis reaction and catalytic hydrogen reaction to obtain a compound of formula (1) (also referred to as compound 1).

[0020] Preferably, the acid hydrolysis reaction uses trifluoroacetic acid / water at room temperature; the alkaline hydrolysis reaction uses lithium hydroxide at 30-37°C and is adjusted to neutral after the reaction is completed; the catalytic hydrogen reaction uses palladium hydroxide / carbon to exchange air in the reaction solution with hydrogen, and the reaction is heated to 30-40°C in a hydrogen environment.

[0021] Furthermore, the organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

[0022] A method for preparing an Acinetobacter baumannii cell wall oligosaccharide fragment comprises the following steps:

[0023] S01: Compound 6 is used as the starting material, dissolved in dry methanol, and sodium methoxide is added to obtain compound 12 through debenzoylation reaction;

[0024] S02: Compound 12 and Compound 13 are subjected to a glycosylation reaction to obtain Compound 14; the glycosylation reaction is to place Compound 12 and Compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0025] As a preference, the acidic reagent is trifluoromethanesulfonic acid.

[0026] S03: dissolving the compound 14 in dry tetrahydrofuran, mixing with a desiliconizing agent, and performing a desiliconization reaction to obtain a compound 15; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid, or tetrabutylammonium fluoride;

[0027] As a preferred embodiment, the desiliconization reagent is triethylamine trihydrofluoric acid.

[0028] S04: The compound 15 is sequentially subjected to acid hydrolysis reaction, reduction reaction, acetylation reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction to obtain a compound of formula (2) (also referred to as compound 2).

[0029] Preferably, the acid hydrolysis reaction is carried out by using water and trifluoroacetic acid with vigorous stirring at room temperature; the reduction reaction is carried out by using 1,3-propanedithiol with stirring at room temperature; the acetylation reaction is carried out by using acetic anhydride with stirring at room temperature; the hydrolysis reaction is carried out by using lithium hydroxide with stirring at room temperature; the catalytic hydrogenation reaction is carried out by using hydrogen and palladium hydroxide with vigorous stirring at room temperature.

[0030] Furthermore, the organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

[0031] A method for preparing an Acinetobacter baumannii cell wall oligosaccharide fragment comprises the following steps:

[0032] S01: Compound 6 is used as the starting material, dissolved in dry methanol, and sodium methoxide is added to obtain compound 12 through debenzoylation reaction;

[0033] S02: Compound 12 and compound 13 are subjected to a glycosylation reaction to obtain compound 14; the glycosylation reaction is to place compound 12 and compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or silver trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0034] S03: dissolving the compound 14 in dry tetrahydrofuran, mixing with a desiliconizing agent, and performing a desiliconization reaction to obtain a compound 15; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid, or tetrabutylammonium fluoride;

[0035] S04: Compound 15 and Compound 10 are subjected to a glycosylation reaction to obtain Compound 16; the glycosylation reaction is to place Compound 15 and Compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or silver trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0036] As a preference, the acidic reagent is trifluoromethanesulfonic acid.

[0037] S05: The compound 16 is sequentially subjected to acid hydrolysis reaction, reduction reaction, acetylation reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction to obtain a compound of formula (3) (also referred to as compound 3).

[0038] As a preferred embodiment, the acid hydrolysis reaction is carried out by using water and trifluoroacetic acid to react vigorously under room temperature; the reduction reaction is carried out by using 1,3-propanedithiol to react vigorously under room temperature; the acetylation reaction is carried out by using acetic anhydride to react vigorously under room temperature; the alkaline hydrolysis reaction is carried out by using lithium hydroxide to react vigorously under room temperature; the catalytic hydrogenation reaction is carried out by using hydrogen and palladium hydroxide to react vigorously under room temperature

[0039] Furthermore, the organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

[0040] A method for preparing an Acinetobacter baumannii cell wall oligosaccharide fragment comprises the following steps:

[0041] S01: Compound 7 is used as a starting material, and compound 5 is added to obtain compound 17 through a glycosylation reaction; the glycosylation reaction is to place the compound 7 and the compound 5 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or silver trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -80°C to -45°C;

[0042] As a preferred embodiment, the acidic reagent is trifluoromethanesulfonic acid;

[0043] As a preferred embodiment, the temperature condition of the glycosidation reaction is -80°C to -60°C;

[0044] S02: Compound 17 is dissolved in dry methanol, and sodium methoxide is added and then subjected to debenzoylation reaction to obtain compound 18;

[0045] S03: Compound 18 and compound 13 are subjected to a glycosylation reaction to obtain compound 19; the glycosylation reaction is to place compound 18 and compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or silver trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0046] As a preferred embodiment, the acidic reagent is trifluoromethanesulfonic acid;

[0047] S04: dissolving the compound 19 in dry tetrahydrofuran, mixing with a desilication agent, and performing a desilication reaction to obtain a compound 20; the desilication agent comprises one or more selected from triethylamine trihydrofluoride, pyridine hydrofluoride, or tetrabutylammonium fluoride;

[0048] As a preferred embodiment, the desiliconization reagent is triethylamine trihydrofluoric acid;

[0049] S05: Compound 20 and compound 10 are subjected to a glycosylation reaction to obtain compound 21; the glycosylation reaction is to place compound 20 and compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or silver trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C;

[0050] As a preferred embodiment, the acidic reagent is trifluoromethanesulfonic acid;

[0051] S06: Compound 21 is sequentially subjected to acid hydrolysis reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction to obtain a compound of formula (4) (Compound 4).

[0052] Preferably, the acid hydrolysis reaction is carried out by using water and trifluoroacetic acid with vigorous stirring at room temperature; the alkaline hydrolysis reaction is carried out by using lithium hydroxide with vigorous stirring at room temperature; and the catalytic hydrogenation reaction is carried out by using hydrogen and palladium hydroxide with vigorous stirring at room temperature.

[0053] Furthermore, the organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

[0054] Use of the above-mentioned compound of formula (1), compound of formula (2), compound of formula (3) and / or compound of formula (4) in the preparation of a vaccine for preventing and / or treating Acinetobacter baumannii infection.

[0055] Furthermore, the terminal of the Acinetobacter mandshurica cell wall oligosaccharide fragment has a short chain with an amino group for conjugation with a carrier protein.

[0056] Beneficial technical effects

[0057] The present invention adopts a divergent synthesis strategy to synthesize four core oligosaccharide fragments of Acinetobacter baumannii, wherein compound 1-3 uses orthogonally protected α-(2→5)-Kdo-Kdo disaccharide as a key precursor, selectively removes the protecting groups at different sites, and then introduces the glycosyl group through a stereoselective glycosylation reaction, thereby constructing the target molecular skeleton. Due to the complex structure of the four target oligosaccharides, the synthesis is difficult, and the synthesis difficulties include the synthesis of α-(2→5) linked Kdo-Kdo disaccharide fragments, the construction of a series of 1,2-cis aminoglycosidic bonds and the assembly of 4,7-branched sugar structures, and the realization of different modifications of multiple amino groups in the structure. Therefore, the method of the present invention and the four core oligosaccharide fragments of Acinetobacter baumannii finally prepared have great potential for industrial application. In addition, since the four core oligosaccharide fragments of Acinetobacter baumannii synthesized are all connected to a short chain with an amino group at the end, they can be used for conjugation with carrier proteins and can be used to prepare vaccines for preventing and / or treating Acinetobacter baumannii infections, and therefore have great clinical application and development value. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0059] Figure 1 is a synthetic flow chart of compound 7;

[0060] Figure 2 is a synthetic flow chart of compound 8;

[0061] Figure 3 is a synthetic flow chart of compound 10;

[0062] Figure 4 is a synthetic flow chart of compound 1;

[0063] Figure 5 is a synthetic flow chart of compounds 2 and 3;

[0064] Figure 6 is a synthetic flow chart of compound 4;

[0065] Figure 7 This is a diagram showing the recognition results of compound 1-4 by serum IgG antibody;

[0066] Figure 8 is the structural identification diagram of compound 1;

[0067] Fig. 9 is the structural identification diagram of compound 2;

[0068] Fig.10 is the structural identification diagram of compound 3;

[0069] Fig.11 This is the result identification diagram of compound 4.

[0070] The chemical formula of the key compound (including key intermediates and final products) involved in the present invention is as follows:

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[0087] DETAILED DESCRIPTION

[0088] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0089] Herein "and / or" includes any and all combinations of one or more of the associated listed items.

[0090] Herein, "plurality" means two or more than two, ie, it includes two, three, four, five, etc.

[0091] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0092] As used in this specification, the term "about" typically means + / - 5% of the stated value, more typically + / - 4% of the stated value, more typically + / - 3% of the stated value, more typically + / - 2% of the stated value, even more typically + / - 1% of the stated value, and even more typically + / - 0.5% of the stated value.

[0093] In this specification, certain embodiments may be disclosed in a format of being in a certain range. It should be understood that such description of "being in a certain range" is merely for convenience and brevity, and should not be interpreted as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered to have specifically disclosed all possible sub-ranges and independent numerical values ​​within this range. For example, the description of the range 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within this range, such as 1, 2, 3, 4, 5 and 6. Regardless of the breadth of the range, the above rules apply.

[0094] Example 1

[0095] The preparation of compound 7, the specific process is shown in Figure 1 .

[0096] Compound S-1 2(2.77g, 5.12mmol) was dissolved in N,N-dimethylformamide (51.0mL), benzyl bromide (1.7mL, 10.34mmol) was added, and the reaction solution was cooled to -20℃ using a low-temperature reactor, and sodium hydride (368.8mg, 15.37mmol) was added to the reaction solution, and the reaction was carried out at -20℃ for 4h. Then water (20.0mL) was slowly added dropwise to terminate the reaction, and dichloromethane (250.0mL) was added to dilute it. It was washed once with ammonium chloride solution (60.0mL), saturated brine (60.0mL) and clean water (60.0mL), the organic phase was dried, filtered, concentrated, and then separated and purified by silica gel column to obtain compound 7 (2.52g, 78%, colorless syrup). 7:R f =0.44 (PE:EA=8:1, v / v); 1 H NMR (400MHz, CDCl3) δ8.05(d,J=7.7Hz,2H),7.57(t,J=7.4Hz,1H),7.45(t,J=7.7Hz,2H ),7.38-7.26(m,5H),4.94-4.85(m,1H),4.57(s,2H),4.53(d,J=2.6Hz,1H),4.40(dd,J =6.8,5.0Hz,1H),3.77(s,3H),3.70(s,1H),3.62-3.50(m,2H),2.94-2.79(m,1H),2.74 -2.57(m,3H),2.54(t,J=12.0Hz,1H),1.22(t,J=7.5Hz,4H),1.14(s,9H),0.92(s,9H). 13 C NMR (101MHz, CDCl3) δ169.9,166.0,138.1,133.2,130.3,129.8,128.5,128.5,127.8,127.8,83.4, 75.7,74.7,73.4,72.3,70.7,66.1,52.8,31.9,27.8,27.2,23.4,22.2,21.7,14.7; HRMS(ESI):m / z calcd for C 33 H 46 O8SSi[M+H] + :631.2755,found:631.2755.

[0097] The preparation of compound 8, the specific process is shown in Figure 2 . Dissolve phenylselenium chloride (4.76 g, 24.85 mmol) in dry dichloromethane (62.1 mL), add silver trifluoromethanesulfonate (6.38 g, 24.85 mmol) and trimethylsilyl trifluoromethanesulfonate (0.5 mL, 2.59 mmol) under ice bath, and stir for 30 minutes. Then add the reaction solution to compound S-2 3 (5.00g, 12.43mmol) and nitrogen-containing short chain 5 (5.20g, 24.85mmol) in dry dichloromethane (62.1mL). After stirring for 2 hours, triethylamine was added dropwise to quench, and dichloromethane (300.0mL) was added to dilute, and then washed once with sodium bicarbonate solution (50.0mL) and clean water (50.0mL), respectively. The organic phase was dried, filtered, concentrated, and then separated and purified by silica gel column to obtain compound S-3 (7.53g, 83%, colorless syrup). S-3: Rf = 0.36 (PE: EA = 4: 3, v / v); 1 H NMR (400MHz, CDCl3) δ7.47-7.39(m,2H),7.39-7.29(m,5H),7.26-7.20(m,3H),5.60(dd,J=5.2,3.1Hz,1H ),5.41(s,1H),5.34(dt,J=9.9,2.8Hz,1H),5.14-5.02(m,2H),4.96(t,J=6.1Hz,1H),4.67(dd,J=12.4,2 .5Hz,1H),4.26-4.15(m,2H),3.83(d,J=5.1Hz,1H),3.66-3.55(m,1H),3.38(s,3H),3.36-3.29(m,1H),3 .27-3.12(m,2H),2.15(s,3H),2.07(s,3H),2.05(s,3H),1.99(s,3H),1.81-1.74(m,2H); HRMS(ESI):m / z calcd for C 34 H 41 NO 14 Se[M+H] + :768.1765,found:768.1763.

[0098] Compound S-3 (7.00 g, 9.13 mmol) was dissolved in toluene (228.3 mL), and tri-n-butyltin hydride (7.4 mL, 27.60 mmol) and azobisisobutyronitrile (1.65 g, 10.05 mmol) were added, and refluxed in an oil bath at 110°C for 4 hours. Then, the mixture was concentrated under reduced pressure and purified by silica gel column to obtain compound S-4 (5.91 g, 88%, colorless syrup). S-4:R f=0.46 (PE:EA=4:3, v / v); 1 H NMR (400MHz, CDCl3) δ7.39-7.27(m,5H),5.39-5.35(m,1H),5.35-5.30(m,1H),5.25-5. 16(m,2H),5.10(s,2H),4.60(dd,J=12.4,2.4Hz,1H),4.13(dd,J=12.4,3.6Hz,1H),4.0 8(d,J=9.8Hz,1H),3.79(s,3H),3.61-3.50(m,1H),3.42-3.22(m,3H),2.14(dd,J=12.8 ,5.0Hz,1H),2.09(s,3H),2.06(s,3H),1.99(s,3H),1.97(s,3H),1.80(p,J=6.4Hz,2H). 13 C NMR (151MHz, CDCl3) δ170.5,170.5,170.0,169.7,168.1,156.5,136.7,128.5,128.1,99.1,68. 4,67.6,66.6,66.3,64.3,62.0,61.6,53.0,38.1,32.1,29.3,20.9,20.8,20.7; HRMS(ESI):m / z calcd for C 28 H 37 NO 14 [M+H] + :612.2287,found:612.2287.

[0099] In an ice bath, compound S-4 (5.20 g, 8.50 mmol) and sodium methoxide (459.20 mg, 8.50 mmol) were added to dry methanol (170.0 mL) and reacted at room temperature for 4 hours. Then, a cation exchange resin was added to adjust the pH to neutral under an ice bath, followed by filtration and concentration under reduced pressure. The product (3.58 g, 92%, colorless syrup) was obtained by separation and purification on a silica gel column.

[0100] The above obtained product (3.58g, 8.07mmol) was dissolved in dry N,N-dimethylformamide (40.4mL), and 2,2-dimethoxypropane (1.5mL, 12.24mmol) and p-toluenesulfonic acid (278.04mg, 1.61mmol) were added. After reacting at room temperature for 4 hours, dichloromethane (200.0mL) was added to dilute, and washed once with sodium bicarbonate solution (50.0mL), saturated brine (50.0mL) and water (50.0mL) respectively. The organic phase was dried, filtered, concentrated, and separated and purified by silica gel column to obtain compound S-5 (3.28g, 84%, colorless syrup). S-5: R f =0.16 (PE:EA=1:2, v / v); 1 H NMR (400MHz, CDCl3) δ7.41-7.28 (m, 5H), 5.46 (t, J = 6.0Hz, 1H), 5.08 (s, 2H), 4.38 ( q,J=6.0Hz,1H),4.12(dd,J=8.4,6.2Hz,1H),4.07-3.98(m,2H),3.96(d,J=3.0Hz,1 H),3.75(s,3H),3.57-3.44(m,2H),3.42-3.21(m,3H),3.10(s,2H),2.09(dd,J=12. 8,5.0Hz,1H),1.88(t,J=12.2Hz,1H),1.82-1.72(m,2H),1.40(s,3H),1.34(s,3H). 13 C NMR (101MHz, CDCl3) δ169.0,156.6,136.7,128.5,128.1,109.4,99.2,73.9,72.7 ,66.7,66.6,66.6,65.7,61.2,52.8,38.1,34.8,29.3,26.8,25.3; HRMS(ESI):m / z calcd for C 23 H 33 NO 10 [M+H] + :484.2177,found:484.2177.

[0101] Dissolve compound S-5 (3.20 g, 6.62 mmol) in dry methanol (132.4 mL), add dibutyltin oxide (Bu2SnO, 3.50 g, 14.06 mmol), reflux for 4 hours and then cool to room temperature. After concentrating and draining the above reaction solution, dissolve it again in dry N,N-dimethylformamide (DMF, 44.1 mL), add benzyl bromide (BnBr, 1.2 mL, 10.10 mmol) and cesium fluoride (CsF, 2.01 g, 13.24 mmol). After reacting for 8 hours, dilute the reaction system with dichloromethane (300.0 mL), wash once with ammonium chloride solution (50.0 mL), saturated brine (50.0 mL) and clean water (50.0 mL), dry the organic phase, filter and concentrate, separate and purify it on a silica gel column to obtain compound 8 (3.20 g, 87%, colorless syrup). 8:R f =0.37 (PE:EA=1:1, v / v); 1 H NMR (400MHz, CDCl3) δ7.37-7.27(m,10H),5.43(d,J=6.5Hz,1H),5.09(s,2H),4.63-4.50(m, 2H),4.47-4.39(m,1H),4.18-4.09(m,2H),4.02(dd,J=8.9,5.1Hz,1H),3.89(ddd,J=11.6,5 .1,3.0Hz,1H),3.76(s,3H),3.53(dd,J=11.4,5.9Hz,2H),3.43-3.23(m,3H),2.19(dd,J=12 .9,5.0Hz,1H),1.99(dd,J=12.8,11.6Hz,1H),1.84-1.64(m,3H),1.42(s,3H),1.36(s,3H). 13 C NMR (101MHz, CDCl3) δ168.9,156.5,128.6,128.6,128.1,128.0,127.7,109.3,99.2,74.0,7 3.1,72.6,70.5,66.7,66.6,64.3,61.3,52.8,38.3,32.3,29.4,26.8,25.5; HRMS(ESI):m / z calcd for C 30 H 39 NO 10 [M+H] + :574.2647,found:574.2647.

[0102] The preparation of compound 10, the specific process is shown in Figure 3 .

[0103] Compound S-6 was dissolved in a mixed solution of dichloromethane (10.0 mL) and methanol (10.0 mL) 4 (1.60g, 2.82mmol), add 1,3-propanedithiol (1.4mL, 14.1mmol) and triethylamine (2.1mL, 14.1mmol). After stirring and reacting for 8 hours at 40°C, concentrate under reduced pressure, and add toluene (50.0mL) again to concentrate under reduced pressure. After repeating twice, separate and purify by silica gel column to obtain a white solid. Then, the eluted white solid was redissolved in dichloromethane (15.0mL), and 2,2,2-trichloroethyl chloroformate (0.4mL, 2.90mmol) was slowly added dropwise under ice bath, and stirred for 1 hour. After the reaction solution was diluted with dichloromethane, it was washed once with sodium bicarbonate solution and water. After the organic phase was dried, filtered and concentrated, it was separated and purified by silica gel column to obtain compound 10 (1.38g, 65%, white solid). 10:R f =0.26 (PE:EA=10:1, v / v); 1 H NMR (400MHz, CDCl3) δ7.52-7.13(m,20H),5.62(d,J=5.1Hz,1H),5.01(d,J=8.8Hz,1H),4.90-4.69(m,4H),4.67-4.59(m,2H),4.56(d,J=10. 8Hz,1H),4.48(d,J=12.0Hz,1H),4.33(d,J=9.8Hz,1H),4.29-4.18(m,1H),3.90-3.76(m,2H),3.69(d,J=10.9Hz,1H),3.62(t,J=9.7Hz,1H). 13 C NMR (101MHz, CDCl3) δ154.1,137.9,137.9,137.8,133.9,131.8,129.2,128.7,128.6,128.5,128.2,128. 1,128.0,128.0,127.8,127.7,89.1,79.8,78.4,75.1,75.1,74.7,73.5,72.5,68.4,55.2; HRMS(ESI):m / z calcd for C 36 H 36 Cl3NO6S[M+H] + :716.1402,found:716.1402.

[0104] Example 2

[0105] The preparation of compound 1, the specific process is shown in Figure 4.

[0106] Dissolve Kdo acceptor 8 (Compound 8) (400.0 mg, 0.72 mmol) and Kdo donor 7 (Compound 7) (650.0 mg, 1.03 mmol) in dry dichloromethane (8.0 mL), add 2.40 g of freshly activated Molecular sieves. Cool at -20℃ for 30 minutes, add N-iodosuccinimide (463.5mg, 2.06mmol) and trifluoromethanesulfonic acid (18.2μL, 0.21mmol), gradually raise the temperature to 0℃, and react for 2 hours. Then add triethylamine dropwise to quench the reaction and filter with diatomaceous earth. After the filtrate is concentrated, it is separated and purified by silica gel column to obtain compound 6 (639.5mg, 79%, colorless syrup). 6:R f =0.36 (PE:EA=2:1, v / v); 1 H NMR (400MHz, CDCl3) δ8.08(d,J=7.2Hz,2H),7.59(t,J=7.4Hz,1H),7.47(t,J=7.6Hz,2H),7.38-7.22(m,15H),5.54(ddd,J=12.4,4.5,2. 5Hz,1H),5.36(t,J=5.3Hz,1H),5.17-5.04(m,2H),4.58-4.50(m,2H),4.50-4.40(m,4H),4.40-4.33(m,1H),4.29-4.23(m,2H),3.91-3. 80(m,3H),3.78(s,3H),3.55(s,3H),3.51-3.43(m,3H),3.42-3.32(m,2H),3.31-3.18(m,2H),2.84(t,J=12.9Hz,1H),2.62(dd,J=13.5, 4.5Hz,1H),2.28(t,J=12.3Hz,1H),2.07(dd,J=12.6,4.4Hz,1H),1.75-1.66(m,2H),1.39(s,3H),1.29(s,3H),1.02(s,9H),0.94(s,9H). 13C NMR (101MHz, CDCl3) δ168.8,168.0,166.0,156.6,138.2,137.7,136.8,133.1,130.6,12 9.7,128.6,128.6,128.5,128.4,128.2,127.9,127.8,127.7,127.6,109.6,100.5,99.3 ,77.4,75.1,74.3,74.0,73.3,73.0,72.4,71.3,70.8,69.7,69.5,67.3,66.7,66.6,61. 3,52.8,52.2,38.2,32.3,29.4,28.3,27.6,27.3,26.9,25.2,22.2,21.5; HRMS(ESI):m / z calcd for C 61 H 79 NO 18 Si[M+H] + :1142.5139,found:1142.5140.

[0107] Dissolve compound 6 (400.0 mg, 0.36 mmol) in dry tetrahydrofuran (5.0 mL), add triethylamine trihydrofluoric acid (0.5 mL, 1 mol / L), and react at room temperature for 8 hours. The reaction solution is diluted with dichloromethane (60.0 mL) and washed once with sodium bicarbonate solution (15.0 mL) and clean water (15.0 mL). The organic phase is dried, filtered, concentrated, and separated and purified by silica gel column to obtain compound 9 (325.6 mg, 93%, colorless syrup). 9:R f =0.38 (PE:EA=1:1, v / v); 1H NMR (400MHz, CDCl3) δ8.08(d,J=7.1Hz,2H),7.57(t,J=7.4Hz,1H),7.44(t,J=7.7Hz,2H),7.38-7.19(m,15H),5.63-5.54(m,1H),5.36(t,J=6.0Hz,1H ),5.16-5.02(m,2H),4.57(d,J=11.8Hz,1H),4.50(s,2H),4.48-4.43(m,2 H),4.43-4.36(m,1H),4.32(s,1H),4.19(d,J=5.5Hz,1H),4.03-3.95(m,2H ),3.92-3.82(m,2H),3.73(s,3H),3.58(s,3H),3.57-3.53(m,2H),3.53-3 .44(m,3H),3.41-3.33(m,1H),3.32-3.20(m,2H),3.07(d,J=5.9Hz,1H),2. 74(t,J=12.9Hz,1H),2.65(dd,J=13.6,4.8Hz,1H),2.30(t,J=12.2Hz,1H), 2.11(dd,J=12.0,4.6Hz,1H),1.79-1.67(m,2H),1.39(s,3H),1.28(s,3H). 13 C NMR (100MHz, CDCl3) δ168.7,168.0,165.8,156.5,137.9,137.5,136.8,133.2,1 30.2,129.8,128.6,128.5,128.4,128.2,128.1,128.0,127.9,127.8,109.6,100 .5,99.3,77.4,74.4,74.0,73.5,73.0,72.1,71.1,70.4,70.1,69.8,69.8,67.3, 66.6,65.9,61.4,52.8,52.4,38.2,32.4,29.4,28.9,27.0,25.2; HRMS(ESI):m / z calcdfor C 53 H 63 NO 18 [M+H] + :1002.4118,found:1002.4116.

[0108] After dissolving donor 10 (compound 10) (350.0 mg, 0.49 mmol) and acceptor 9 (compound 9) (240.0 mg, 0.24 mmol) in dry dichloromethane (5.0 mL), 1.50 g of freshly activated Molecular sieves, cooled at -20℃ for 20 minutes, N-iodosuccinimide (165.0 mg, 0.73 mmol) and trimethylsilyl trifluoromethanesulfonate (16.0 L, 0.09 mmol) were added. Then the reaction system was gradually heated to 0℃ and reacted for 2 hours. After adding triethylamine dropwise, the mixture was separated and purified by silica gel column to obtain compound 11 (310.4 mg, 80%, colorless syrup). 11:R f =0.56 (PE:EA=1:1, v / v); 1 H NMR (400MHz, CDCl3) δ8.09 (d, J = 7.7Hz, 2H), 7.53 (t, J = 7.3Hz, 1H), 7.45-7.16 (m, 30H), 7.08-7.00 (m, 2H), 5.63 (d, J = 12.2Hz, 1H), 5.34-5.28 (m ,1H),5.24(d,J=7.8Hz,1H),5.16-5.05(m,2H),4.74(d,J=12.0Hz,1H), 4.69-4.37(m,14H),4.31(d,J=12.2Hz,1H),4.13(d,J=7.9Hz,2H),4.09- 4.00(m,2H),3.95-3.82(m,3H),3.75(s,3H),3.67-3.60(m,1H),3.60-3 .50(m,3H),3.49-3.44(m,4H),3.45-3.30(m,5H),3.26(s,2H),2.81(t, J=13.1Hz,1H),2.67(dd,J=13.2,3.4Hz,1H),2.35(t,J=12.2Hz,1H),2.13(dd,J=12.5,3.8Hz,1H),1.78-1.65(m,2H),1.41(s,3H),1.32(s,3H); 13CNMR(151MHz, CDCl3)δ168.7,168.1,165.9,156.5,154.7,138.4,138.1,137.7,137.7,137.5,136.8,133.0,130.6, 129.8,128.6,128.6,128.5,128.5,128.5,128.4,128.4,128.2,128.1,128.1,128.0,127.9,127.9,127.8,127.8,1 09.8,102.5,100.6,99.4,95.8,83.2,78.3,78.0,75.2,75.0,74.7,74.6,74.6,73.9,73.5,73.4,72.9,72.9,71.9, 70.8,69.9,69.0,68.9,67.8,66.6,63.6,61.4,57.6,52.8,52.2,38.3,32.0,29.4,28.2,26.9,25.3; HRMS(ESI):m / z calcd for C 83 H 93 Cl3N2O 24 [M+H] + :1607.5257,found:1607.5257.

[0109] Compound 11 (60.0 mg, 0.04 mmol) was dissolved in dichloromethane (4.0 mL), and trifluoroacetic acid / water (0.5 mL, 9:1, v / v) was added under ice bath, and stirred at room temperature for 1 hour. After the reaction was complete, the reaction solution was diluted with dichloromethane (10.0 mL) and the filtrate was washed with sodium bicarbonate solution (5.0 mL) and water (5.0 mL), and the organic phase was dried and concentrated.

[0110] The concentrated product from the previous step was redissolved in tetrahydrofuran solvent / water (3.0 mL, 2:1, v / v), lithium hydroxide (40.0 mg, 1.67 mmol) was added, and stirred at 35°C for 8 hours. After the reaction was complete, the pH value was adjusted to neutral with a cation exchange resin, and then filtered and concentrated under reduced pressure.

[0111] The concentrated product of the previous step was redissolved in tetrahydrofuran solvent / water (3.0 mL, 2:1, v / v), palladium hydroxide / carbon (80.0 mg) was added, and the air in the reaction solution was replaced by external hydrogen, and the reaction was gradually heated to 30°C in a hydrogen environment for 24 hours. After the reaction was complete, the reaction solution was filtered with diatomaceous earth, and the filtrate was lyophilized and concentrated under reduced pressure. The concentrated crude product was separated and purified by BioGel P-2 molecular exclusion chromatography column, and the purified product aqueous solution was freeze-dried to obtain compound 1 (13.1 mg, 55%, white foam).

[0112] Compound 1:R f =0.21(MeOH:H2O=5:1, v / v); 1 H NMR(400MHz,D2O)δ4.44(d,J=8.1Hz,1H),4.32-4.24(m,1H),4.11-3.89(m,6H),3.90-3.79(m,3H),3.67-3.48(m,4H),3.41-3.34(m,1H) ,3.33-3.18(m,3H),3.14-2.92(m,3H),2.66-2.58(m,1H),2.19(dd,J=12.9,4.7Hz,1H),1.91(dd,J=12.8,4.5Hz,1H),1.87-1.73(m,4H); 13 CNMR(151MHz,D2O)δ175.4,173.6,102.5,102.0,100.3,77.8,75.8,75.6,73.6,71.8,71.5,70. 0,69.1,66.2,65.7,65.1,62.1,61.7,60.9,59.8,56.2,38.4,36.1,35.1,26.2; HRMS(ESI):m / z calcd for C 27 H 44 N2O 21 [M+H] + :733.2510,found:733.2511.

[0113] Example 3

[0114] The preparation of compound 2 and compound 3, the specific process is shown in Figure 5 .

[0115] Compound 2:

[0116] Compound 6 (830.0 mg, 0.74 mmol) was dissolved in dry methanol (10 mL), and sodium methoxide (40.0 mg, 0.74 mmol) was added. After stirring at room temperature for two days, a cation exchange resin was added under ice bath to adjust the pH value to 7, and then the mixture was filtered, concentrated, and separated and purified by silica gel column to obtain compound 12 (640.2 mg, 85%, colorless syrup). 12:R f =0.40 (PE:EA=4:3, v / v); 1H NMR (400MHz, CDCl3) δ7.38-7.21(m,15H),5.37(t,J=6.1Hz,1H),5.17-5.02(m,2H),4.60(d,J=11.8Hz,1H),4.44(d, J=12.1Hz,1H),4.41-4.36(m,2H),4.32-4.26(m,1H),4.23(dd,J=7.3,2.5Hz,2H),4.13(s,1H),4.11-4.05(m,2H),4. 00-3.89(m,2H),3.75(s,3H),3.73-3.69(m,1H),3.63(s,3H),3.52-3.42(m,1H),3.42-3.15(m,6H),2.46(dd,J=13. 3, 4.6Hz, 1H), 2.20 (t, J = 12.4Hz, 1H), 2.14-2.01 (m, 2H), 1.78-1.66 (m, 2H), 1.36 (s, 3H), 1.28 (s, 3H), 1.00 (s, 18H). 13 C NMR (100MHz, CDCl3) δ168.7,167.9,156.6,138.2,137.7,136.8,128.6,128. 4,128.2,128.2,127.9,127.7,127.7,109.3,100.3,99.1,75.0,74.0,73.9, 73.4,73.3,72.9,71.4,70.8,69.5,69.2,66.7,66.6,65.7,61.3,52.8,52.3 ,38.2,34.0,32.9,29.4,27.6,27.3,27.0,25.3,22.2,21.6; HRMS(ESI):m / z calcd for C 54 H 75 NO 17 Si[M+H] + :1038.4877,found:1038.4879.

[0117] Dry dichloromethane (11.0 mL) was used to dissolve donor 13 5 (Compound 13) (550.0 mg, 0.76 mmol) and receptor 12 (Compound 12) (370.0 mg, 0.36 mmol), 3.30 g of freshly activated Molecular sieves. Cool at -20°C for 30 minutes, add N-iodosuccinimide (341.9 mg, 1.52 mmol) and trifluoromethanesulfonic acid (13.4 L, 1.52 mmol). The reaction system is gradually raised to 0°C and reacted for 2 hours. After adding triethylamine dropwise, the compound 14 (418.6 mg, 76%, colorless syrup) is obtained by separation and purification on a silica gel column. 14:R f =0.71 (PE:EA=4:3, v / v); 1 H NMR (400MHz, CDCl3) δ7.70-7.66(m,2H),7.66-7.61(m,2H),7.40-7.19(m,26H) ,5.48(t,J=9.6Hz,1H),5.38(t,J=6.1Hz,1H),5.20(d,J=3.4Hz,1H),5.16-5.0 4(m,2H),4.80(d,J=11.1Hz,1H),4.64(d,J=11.1Hz,1H),4.51(d,J=12.1Hz,1H ),4.46-4.43(m,1H),4.43-4.31(m,3H),4.27-4.20(m,2H),4.15-4.07(m,3H),4 .05(s,1H),3.98-3.88(m,3H),3.73(d,J=2.2Hz,2H),3.68-3.62(m,1H),3.60( s,3H),3.47(s,3H),3.46-3.37(m,2H),3.37-3.12(m,6H),2.71-2.55(m,2H),2 .51(t,J=12.5Hz,1H),2.46-2.29(m,3H),2.13(s,3H),2.04-1.90(m,2H),1.74 -1.67(m,2H),1.29(s,3H),1.27(s,3H),1.05(s,9H),1.01(s,9H),1.00(s,9H); 13C NMR (101MHz, CDCl3) δ206.2,171.1,168.6,167.6,156.6,138.3,138.0,137.8,136.8,135.8,133.6,133.5,129.7,129. 6,128.6,128.5,128.4,128.4,128.3,128.2,128.0,127.9,127.8,127.7,127.7,127.7,127.6,109.2,100.0,99.1,95. 8,77.4,75.2,74.1,73.9,73.7,73.5,73.2,72.8,72.7,71.5,71.1,70.8,69.8,69.3,66.6,66.4,66.3,62.7,61.9,61. 2,52.6,52.4,38.1,38.0,33.2,32.2,30.0,29.5,28.1,27.7,27.3,27.0,26.8,25.4,22.3,21.6,19.4; HRMS(ESI):m / z calcd for C 88 H 114 N4O 23 Si2[M+H] + :1651.7485,found:1651.7485.

[0118] Compound 14 (400.0 mg, 0.36 mmol) was dissolved in dry tetrahydrofuran (10.0 mL), and triethylamine trihydrofluoric acid (1.5 mL, 1 mol / L) was added and reacted at room temperature for 3 days. The reaction solution was then diluted with dichloromethane (60.0 mL) and washed once with sodium bicarbonate solution (15.0 mL) and clean water (15.0 mL). The organic phase was dried, filtered, concentrated, and purified by silica gel column separation.

[0119] The product separated and purified in the previous step was dissolved in dichloromethane (4.4 mL), and water (0.1 mL), 2,2,6,6-tetramethylpiperidinoxide (6.9 mg, 0.44 mmol) and iodophenyl diacetic acid (106.3 mg, 0.33 mmol) were added in turn under ice bath, and the mixture was stirred vigorously at room temperature for 4 hours. The reaction solution diluted with dichloromethane (30.0 mL) was washed once with saturated sodium thiosulfate aqueous solution (10.0 mL), sodium bicarbonate solution (10.0 mL) and clean water (10.0 mL), respectively. The organic phase was dried, filtered and concentrated. The concentrated crude product was redissolved in N,N-dimethylformamide (5.0 mL), and iodomethane (0.2 mL, 3.2 mmol) and potassium carbonate (30.4 mg, 0.22 mmol) were added in turn under ice bath, and the mixture was gradually warmed to room temperature and stirred for 6 hours. After the reaction is complete, dichloromethane (40.0 mL) is added to dilute, and the mixture is washed once with saturated ammonium chloride solution (15.0 mL), once with saturated saline (15.0 mL), and once with water (10.0 mL). The organic phase is dried, filtered, and concentrated. Compound 15 (198.1 mg, 70%, colorless syrup) is obtained by separation and purification on a silica gel column. 15:R f =0.41 (PE:EA=1:2, v / v); 1H NMR(400MHz,CDCl3)δ7.41-7.24(m,20H),5.33(t,J=6.0Hz,1H),5.17(t,J=9.4Hz,1H),5.11(d,J=3.6Hz,1H),5.10-5.03(m,2H),4.82(d,J=11.2Hz,1H),4.74(d,J=11.2Hz,1H),4.56(d,J=12.0Hz,1H),4.51-4.43(m,3H),4.37(d,J=9.9Hz,1H),4.34-4.24(m,2H),4.21(s,1H),4.16(s,1H),4.10-4.03(m,2H),4.03-3.93(m,2H),3.88(dd,J=8.9,4.5Hz,1H),3.78(d,J=11.5Hz,1H),3.68(s,3H),3.67(s,3H),3.63(s,3H),3.62-3.52(m,3H),3.50-3.42(m,1H),3.39(d,J=8.3Hz,1H),3.36-3.14(m,4H),2.75-2.62(m,2H),2.62-2.48(m,2H),2.47-2.35(m,2H),2.18(t,J=12.5Hz,1H),2.16(s,3H),2.09(dd,J=12.6,4.5Hz,1H),1.77-1.62(m,2H),1.32(s,3H),1.27(s,3H); 13 C NMR(101MHz,CDCl3)δ205.9,171.5,168.5,168.1,167.8,156.4,138.0,137.5,137.4,136.7,128.5,128.5,128.4,128.4,128.1,128.1,128.0,128.0,127.8,127.7,109.3,100.1,99.1,95.2,77.7,75.3,74.0,73.8,73.3,73.0,72.8,71.6,71.5,70.8,70.5,69.9,69.7,69.6,66.9,66.5,64.2,62.8,61.2,52.9,52.6,52.4,38.0,37.6,32.4,30.5,29.8,29.4,27.7,26.8,25.3;HRMS(ESI):m / z calcd for C 65 H 80 N4O 24 [M+H] +:1301.5235,found:1301.5235.

[0120] Dissolve compound 15 (50.0 mg, 0.038 mmol) in dichloromethane (3.8 mL) and cool in an ice bath for 20 minutes, add trifluoroacetic acid (0.3 mL) and two drops of water. After vigorous stirring at room temperature for 1 hour, add dichloromethane (40.0 mL) to dilute and wash with saturated sodium bicarbonate solution (10.0 mL) and water (10.0 mL). Dry the organic phase, filter and concentrate.

[0121] The concentrated crude product was redissolved in dry dichloromethane (2.0 mL), and methanol (2.0 mL), 1,3-propanedithiol (0.5 mL) and triethylamine (0.3 mL) were added in sequence. After stirring at room temperature for 12 hours, the reaction solution was directly concentrated under reduced pressure. The concentrated crude product was redissolved in toluene (about 10 mL), concentrated under reduced pressure, and repeated twice.

[0122] The crude product obtained by concentration in the previous step was re-dissolved in pyridine (3.0 mL), and acetic anhydride (0.3 mL, 3.2 mmol) and 4-dimethylaminopyridine (2.0 mg, 0.016 mmol) were added in turn under ice bath. After stirring and reacting for 4 hours at room temperature, the reaction solution was washed with saturated sodium bicarbonate solution (10.0 mL) and clean water (10.0 mL), and then diluted with dichloromethane (50.0 mL). The organic phase was dried, filtered, concentrated, and quickly separated and purified by silica gel column.

[0123] The eluted product from the previous step was dissolved in methanol (4.0 mL), and sodium hydroxide solution (1.0 mL, 1.0 mol / L) was added dropwise under ice bath, and stirred at 35°C for 8 hours. The mixture was cooled in ice bath, and the pH value was adjusted to 8 with cation exchange resin, and then filtered and concentrated.

[0124] The concentrated product of the previous step was redissolved in tetrahydrofuran (2.0 mL), and water (2.0 mL) and palladium hydroxide / carbon (50.0 mg) were added, and hydrogen was added externally to exchange the air in the reaction solution, and the reaction was gradually heated to 30°C under a hydrogen environment for 24 hours. After the reaction was complete, the reaction solution was filtered with diatomaceous earth, and the filtrate was lyophilized and concentrated under reduced pressure. The concentrate was separated and purified by BioGel P-2 molecular exclusion chromatography column, and the purified product aqueous solution was freeze-dried to obtain product 2 (11.2 mg, 40%, white foam).

[0125] Compound 2:R f =0.23 (MeOH:H2O=6:1, v / v); (c 0.80, CHCl3); 1H NMR(400MHz,D2O)δ5.03(d,J=3.7Hz,1H),4.35-4.26(m,1H),4.07(dd,J=11.7,2.7Hz,2H ),4.00-3.93(m,2H),3.92-3.80(m,5H),3.73-3.61(m,3H),3.59-3.44(m,4H),3.23(td, J=9.2,3.9Hz,1H),3.08(dt,J=12.0,5.8Hz,1H),3.02-2.92(m,1H),2.27(dd,J=13.3,4. 7Hz,1H),2.00(t,J=12.6Hz,1H),1.96(s,3H),1.93-1.76(m,3H),1.70(t,J=12.5Hz,1H); 13 C NMR(151MHz,D2O)δ178.9,178.1,177.0,176.3,104.5,103.0,98.8,75.8,75.1,75.0,75.0,74.4, 74.3,73.4,72.9,71.7,68.3,67.2,64.9,64.3,55.9,41.0,37.8,36.9,28.7,24.5; HRMS(ESI):m / z calcd for C 25 H 44 N2O 19 [M+H] - :677.2612,found:677.2614.

[0126] Compound 3:

[0127] After dissolving the donor 10 (compound 10) (150.0 mg, 0.21 mmol) and the acceptor 15 compound (15) (131.0 mg, 0.10 mmol) in dry dichloromethane (3.0 mL), 900 mg of freshly activated Molecular sieves. Cool at -20℃ for 30 minutes, add N-iodosuccinimide (71.0 mg, 0.31 mmol) and trifluoromethanesulfonic acid (3.7 μL, 0.042 mmol). The reaction system gradually rises to 0℃ and reacts for 4 hours. After adding triethylamine dropwise, the mixture is separated and purified by silica gel column to obtain compound 16 (153.7 mg, 80%, colorless syrup). Compound 16: R f =0.29 (PE:EA=1:1, v / v); 1H NMR(400MHz,CDCl3)δ7.41-7.20(m,33H),7.10-7.03(m,2H),5.31(t,J=6.0Hz,1H),5.23(d,J=3.5Hz,1H),5.20-5.14(m,1H),5.13-5.04(m,2H),4.77-4.55(m,8H),4.44(tt,J=11.3,5.8Hz,6H),4.38-4.26(m,4H),4.21(s,1H),4.18-4.05(m,3H),3.92-3.85(m,3H),3.81-3.74(m,1H),3.73(s,3H),3.63(s,3H),3.62-3.54(m,3H),3.50(s,3H),3.49-3.11(m,10H),2.72-2.55(m,3H),2.54-2.43(m,2H),2.34(dt,J=17.3,6.5Hz,1H),2.19(t,J=12.2Hz,1H),2.13(s,3H),2.09(dd,J=12.7,4.5Hz,3H),1.77-1.66(m,2H),1.34(s,3H),1.31(s,3H); 13 C NMR(151MHz,CDCl3)δ206.0,171.6,168.6,168.4,167.9,156.5,154.8,138.3,138.1,137.8,137.7,137.7,137.7,136.8,128.6,128.6,128.5,128.5,128.3,128.2,128.1,128.0,128.0,127.9,127.9,127.8,127.8,109.5,102.4,100.3,99.2,96.7,95.8,83.2,78.4,77.6,77.0,75.2,75.1,74.8,74.7,74.6,74.3,73.9,73.5,73.3,73.1,73.0,72.9,72.1,71.7,70.7,69.9,69.7,69.0,67.2,66.6,63.0,62.1,61.1,57.6,52.9,52.8,52.3,38.1,37.6,32.2,30.6,29.9,29.4,27.7,26.9,25.4;HRMS(ESI):m / z calcd forC 95 H 110 Cl3N5O 30 [M+H] + :1907.6408,found:1907.6408。

[0128] Dissolve compound 16 (75.0 mg, 0.039 mmol) in dichloromethane (5.0 mL) and cool in an ice bath for 20 minutes, add trifluoroacetic acid (0.6 mL) and two drops of water. After vigorous stirring at room temperature for 1 hour, add dichloromethane (40.0 mL) to dilute and wash with saturated sodium bicarbonate solution (10.0 mL) and water (10.0 mL). Dry the organic phase, filter and concentrate.

[0129] The concentrated crude product was redissolved in dry dichloromethane (2.0 mL), and methanol (2.0 mL), 1,3-propanedithiol (0.5 mL) and triethylamine (0.3 mL) were added in sequence. After stirring at room temperature for 12 hours, the reaction solution was directly concentrated under reduced pressure. The concentrated crude product was redissolved in toluene (about 10 mL), concentrated under reduced pressure, and repeated twice.

[0130] The crude product obtained by concentration in the previous step was re-dissolved in pyridine (4.0 mL), and acetic anhydride (0.3 mL, 3.2 mmol) and 4-dimethylaminopyridine (2.0 mg, 0.016 mmol) were added in turn under ice bath. After stirring and reacting for 4 hours at room temperature, the reaction solution was washed with saturated sodium bicarbonate solution (10.0 mL) and clean water (10.0 mL), and then diluted with dichloromethane (50.0 mL). The organic phase was dried, filtered, concentrated, and quickly separated and purified by silica gel column.

[0131] The eluted product from the previous step was dissolved in tetrahydrofuran / water (4.0 mL, 1 / 1, v / v), lithium hydroxide (40.0 mg, 1.67 mmol) was added under ice bath, and the mixture was stirred at 35°C for 12 hours. The mixture was cooled under ice bath, the pH value was adjusted to 8 with cation exchange resin, and then filtered and concentrated.

[0132] The concentrated product of the previous step was redissolved in tetrahydrofuran (2.0 mL), and water (2.0 mL) and palladium hydroxide / carbon (50.0 mg) were added, and the air in the reaction solution was replaced by external hydrogen, and the reaction was gradually heated to 30° C. under a hydrogen environment for 24 hours. After the reaction was complete, the reaction solution was filtered with diatomaceous earth, and the filtrate was lyophilized and concentrated under reduced pressure. The concentrate was separated and purified by BioGel P-2 molecular exclusion chromatography column, and the purified product aqueous solution was freeze-dried to obtain compound 3 (19.3 mg, 55%, white foam).

[0133] Compound 3:R f =0.21(MeOH:H2O=5:1, v / v); 1H NMR(400MHz,D2O)δ5.00(d,J=3.5Hz,1H),4.55(d,J=8.2Hz,1H),4.38-4.30(m,1H),4.15-4.10(m,1H),4. 07-4.00(m,2H),4.00-3.86(m,4H),3.86-3.73(m,5H),3.68(t,J=9.0Hz,1H),3.58-3.43(m,6H),3.40-3. 32(m,2H),3.26(d,J=9.2Hz,1H),3.24-3.17(m,1H),3.06(dt,J=12.0,5.8Hz,1H),3.01-2.91(m,1H),2.7 3(t,J=9.1Hz,1H),2.22(dd,J=13.0,4.5Hz,1H),1.98(d,J=13.0Hz,1H),1.95(s,3H),1.88-1.71(m,4H); 13 C NMR(101MHz,D2O)δ176.3,175.4,174.4,173.5,101.9,100.8,100.4,95.7,77.6,76.0,74.5,73.5,72.5,72.4,71.7,71 .6,71.5,70.9,70.1,69.2,65.8,64.1,62.3,61.6,61.1,59.8,56.1,53.3,38.4,35.2,34.5,26.1,22.0; HRMS(ESI):m / z calcd for C 33 H 55 N3O 25 [M+H] + :894.3198,found:894.3202.

[0134] Example 4

[0135] The preparation of compound 4, the specific process is shown in Figure 6 .

[0136] After dissolving donor 7 (compound 7) (1.27 g, 2.01 mmol) and short-chain acceptor 5 (compound 5) (500.0 mg, 2.34 mmol) in dry dichloromethane (33.0 mL), 10.0 g of freshly activated Molecular sieves, cooled at -20℃ for 30 minutes, N-iodosuccinimide (543.0 mg, 2.41 mmol) and trifluoromethanesulfonic acid (21.0 L, 0.24 mmol) were added. The temperature was gradually raised to 0℃ for reaction for 2 hours. After quenching with triethylamine, the mixture was filtered through diatomaceous earth, the filtrate was concentrated, and the compound 17 (1.38 g, 88% based on the donor, colorless syrup) was obtained by separation and purification on a silica gel column. 17:R f =0.35 (PE:EA=3:1, v / v); 1 H NMR (400MHz, CDCl3) δ8.04(d,J=7.7Hz,2H),7.57(t,J=7.4Hz,1H),7.44(t,J=7.6Hz,2H),7.38-7.25(m,10H),5 .38-5.28(m,1H),5.23(t,J=6.1Hz,1H),5.16-5.03(m,2H),4.62-4.47(m,3H),4.38(dd,J=9.2,4.6Hz,1H),3.91 (s,1H),3.76(s,3H),3.60(dd,J=9.5,4.6Hz,1H),3.48(t,J=9.4Hz,2H),3.34(td,J=9.1,8.7,4.8Hz,1H),3.26- 3.13(m,2H),2.42(t,J=12.1Hz,1H),2.21(dd,J=12.4,4.9Hz,1H),1.71-1.57(m,2H),1.10(s,9H),0.91(s,9H); 13 C NMR (101MHz, CDCl3) δ168.8,166.0,156.5,137.8,136.9,133.2,130.3,129.7,128.6,128.5,128.5,128.2,128.1,127.9,1 27.9,99.1,75.0,73.3,71.5,71.0,69.8,66.5,65.6,61.3,52.6,38.2,31.7,29.1,27.6,27.2,22.1,21.6; HRMS(ESI):m / z calcd for C 42 H 55 NO 11 Si[M+H] + :778.3617,found:778.3617.

[0137] Compound 17 (840.0 mg, 1.08 mmol) was dissolved in dry methanol (20.0 mL), and sodium methoxide (50.0 mg, 0.92 mmol) was added. After stirring at room temperature for 16 hours, a cation exchange resin was added under ice bath to adjust the pH value to 7, and then the mixture was filtered, concentrated, and separated and purified by silica gel column to obtain compound 18 (683.9 mg, 94%, colorless syrup). 18:R f =0.30 (PE:EA=2:1, v / v); 1 H NMR (400MHz, CDCl3) δ7.38-7.22(m,10H),5.21(t,J=6.1Hz,1H),5.15-5.04(m,2H),4.52(s,2H),4.37(dd,J= 9.1,4.6Hz,1H),4.22(d,J=3.1Hz,1H),4.01-3.89(m,1H),3.78(s,1H),3.74(s,3H),3.59(dd,J=9.6,4.5Hz, 1H),3.47(t,J=9.3Hz,1H),3.45-3.39(m,1H),3.29(dt,J=9.6,6.1Hz,1H),3.25-3.09(m,2H),2.40(d,J=11. 1Hz,1H),2.13(dd,J=12.6,5.0Hz,1H),1.89(t,J=12.0Hz,1H),1.67-1.55(m,2H),1.07(s,9H),1.00(s,9H); 13 C NMR (101MHz, CDCl3) δ169.0,156.5,137.8,136.9,128.6,128.5,128.2,128.1,128.0,127.8,99.2,74.8, 73.4,71.5,70.8,67.9,66.5,66.0,61.4,52.6,38.3,35.6,29.1,27.5,27.3,22.2,21.6; HRMS(ESI):m / z calcd forC 35 H 51 NO 10 Si[M+H] + :674.3355,found:674.3355.

[0138] After dissolving donor 13 (Compound 13) (1.10 g, 1.52 mmol) and acceptor 18 (Compound 18) (510.0 mg, 0.76 mmol) in dry dichloromethane (20.0 mL), 6.0 g of freshly activated Molecular sieves, cooled at -20℃ for 30 minutes, N-iodosuccinimide (683.0 mg, 3.03 mmol) and trifluoromethanesulfonic acid (27.0 L, 0.31 mmol) were added. The temperature was gradually raised to 0℃ for reaction for 2 hours. After quenching with triethylamine, the mixture was filtered through diatomaceous earth, the filtrate was concentrated, and the compound 19 (789.4 mg, 81%, colorless syrup) was obtained by separation and purification on a silica gel column. 19:R f =0.39 (PE:EA=2:1, v / v); 1 H NMR (400MHz, CDCl3) δ7.70-7.63(m,4H),7.40-7.32(m,8H),7.31-7.23(m,8H),5.20- 5.13(m,2H),5.09(t,J=6.1Hz,1H),5.04(s,2H),4.78(d,J=11.1Hz,1H),4.63(d,J=1 1.1Hz,1H),4.52(s,2H),4.45(d,J=2.6Hz,1H),4.38(dd,J=9.2,4.6Hz,1H),4.12-4. 07(m,1H),4.07-4.01(m,1H),3.88-3.82(m,1H),3.75(s,1H),3.71(s,3H),3.69-3.66 (m,2H),3.62(dd,J=9.6,4.6Hz,1H),3.50(t,J=9.4Hz,1H),3.42(dt,J=10.4,5.3Hz, 1H),3.28(ddd,J=9.8,7.3,5.5Hz,1H),3.20(dd,J=10.4,3.5Hz,1H),3.08(q,J=6.2Hz ,2H),2.56(t,J=6.3Hz,2H),2.33(t,J=6.7Hz,2H),2.26(d,J=12.1Hz,1H),2.11(s,3 H),2.08(dd,J=4.8Hz,1H),1.59-1.50(m,2H),1.08(s,9H),1.05(s,9H),1.02(s,9H). 13C NMR (151MHz, CDCl3) δ206.1,171.4,168.9,156.4,137.9,137.8,136.9,135.8,135.8,133.5, 133.3,129.8,129.8,128.6,128.6,128.5,128.2,128.1,128.1,128.0,127.9,127.8,127.8,1 27.7,99.2,94.6,77.0,74.9,74.2,73.3,71.4,71.3,71.0,70.8,70.6,66.6,64.1,62.7,62.4 ,61.2,52.6,37.9,37.9,33.0,29.9,29.0,28.0,27.7,27.2,26.9,22.3,21.6; HRMS(ESI):m / z calcd for C 69 H 90 N4O 16 Si2[M+H] + :1287.5963,found:1287.5963.

[0139] Compound 19 (720.0 mg, 0.56 mmol) was dissolved in dry tetrahydrofuran (10.0 mL), and triethylamine trihydrofluoric acid (1.0 mL, 1 mol / L) was added to react at room temperature for 24 hours. The reaction solution was then diluted with dichloromethane (60.0 mL) and washed once with sodium bicarbonate solution (15.0 mL) and clean water (15.0 mL). The organic phase was dried, filtered, concentrated, and purified by silica gel column separation.

[0140] The product separated and purified in the previous step was dissolved in dichloromethane (10.0 mL), and water (0.1 mL), 2,2,6,6-tetramethylpiperidinoxide (10.0 mg, 0.13 mmol) and iodophenyl diacetic acid (240.0 mg, 0.75 mmol) were added in turn under ice bath, and the mixture was stirred vigorously at room temperature for 4 hours. The reaction solution diluted with dichloromethane (30.0 mL) was washed once with saturated sodium thiosulfate aqueous solution (10.0 mL), sodium bicarbonate solution (10.0 mL) and clean water (10.0 mL), respectively. The organic phase was dried, filtered and concentrated. The concentrated crude product was redissolved in N,N-dimethylformamide (5.0 mL), and iodomethane (0.2 mL, 3.21 mmol) and potassium carbonate (86 mg, 0.62 mmol) were added in turn under ice bath, and the mixture was gradually warmed to room temperature and stirred for 6 hours. After the reaction is complete, dichloromethane (40.0 mL) is added to dilute, and the mixture is washed once with saturated ammonium chloride solution (15.0 mL), once with saturated saline (15.0 mL), and once with water (10.0 mL). The organic phase is dried, filtered, and concentrated. Compound 20 (421.8 mg, 83%, colorless syrup) is obtained by separation and purification on a silica gel column. f =0.36 (PE:EA=1:2, v / v); (400MHz, CDCl3) δ7.37-7.27(m,15H),5.14-5.04(m,5H),4.79(d,J=11.2Hz,1H),4.73(d,J=10.8Hz,1H ),4.58-4.49(m,2H),4.28(d,J=10.0Hz,1H),4.23-4.15(m,2H),4.14-4.03(m,1H),3.98(t,J=9.4Hz,1 H),3.77(s,3H),3.75(dd,J=5.9,2.3Hz,1H),3.71(s,3H),3.64-3.57(m,2H),3.55-3.44(m,1H),3.31- 3.13(m,3H),2.78-2.49(m,4H),2.46-2.34(m,1H),2.17(s,3H),2.13-2.02(m,2H),1.73-1.47(m,2H); 13CNMR(101MHz, CDCl3)δ206.0,171.7,168.8,168.3,156.5,137.7,137.4,136.8,128.6,128.6,128.2,128.2,128.2,128.1,98.9,94.9, 75.5,73.7,73.3,71.8,71.0,70.6,69.6,68.5,66.7,63.0,62.8,60.8,53.1,52.9,37.9,37.7,32.8,29.9,29.2,27.8; HRMS(ESI):m / z calcd for C 46 H 56 N4O 17 [M+H] + :937.3713,found:937.3713.

[0141] Donor 10 (Compound 10) (450.0 mg, 0.63 mmol) and acceptor 20 (Compound 20) (360.0 mg, 0.38 mmol) were dissolved in dry dichloromethane (10.0 mL) and freshly activated Molecular sieves (3.0 g), stirred at room temperature for 10 minutes. The reaction system was then cooled in a -20°C low-temperature reactor for 30 minutes, and N-iodosuccinimide (270.0 mg, 1.20 mmol) and trifluoromethanesulfonic acid (11.0 L, 0.12 mmol) were added. After reacting for 2 hours, triethylamine was added dropwise, filtered with diatomaceous earth, and the filtrate was concentrated. Compound 21 (474.6 mg, 80%, colorless syrup) was obtained by separation and purification on a silica gel column. 21:R f =0.60(PE:EA=1:2,v / v); 1H NMR(400MHz,CDCl3)δ7.42-7.19(m,28H),7.10-7.03(m,2H),5.20(d,J=3.1Hz,1H),5.18-5.06(m,4H),4.80-4.55(m,9H),4.52(s,2H),4.47-4.40(m,2H),4.37(s,1H),4.30(d,J=9.8Hz,1H),4.24-4.18(m,1H),4.13-4.06(m,1H),4.03(t,J=9.4Hz,1H),3.85-3.78(m,1H),3.76(s,3H),3.71(s,3H),3.69-3.62(m,2H),3.61-3.38(m,7H),3.38-3.13(m,4H),2.69-2.58(m,2H),2.57-2.43(m,1H),2.35(dt,J=17.3,6.5Hz,1H),2.26(t,J=12.2Hz,1H),2.15(s,3H),2.08(dd,J=12.5,4.5Hz,1H),1.71-1.60(m,2H); 13 C NMR(151MHz,CDCl3)δ206.0,171.6,168.9,168.4,156.5,154.5,138.0,138.0,137.6,137.6,137.6,136.9,128.7,128.6,128.6,128.5,128.5,128.3,128.2,128.1,128.1,128.0,128.0,127.9,101.7,99.2,95.6,95.3,82.2,78.6,75.2,75.1,74.9,74.6,74.6,73.8,73.4,72.4,71.7,71.5,71.5,69.5,68.9,66.6,62.1,61.9,61.2,57.7,53.1,52.8,38.0,37.7,33.0,29.9,29.2,27.8;HRMS(ESI):m / z calcd forC 76 H 86 Cl3N5O 23 [M+H] + :1542.4852,found:1542.4852。

[0142] Compound 21 (50.0 mg, 0.032 mmol) was dissolved in dichloromethane (1.5 mL), methanol (1.5 mL), 1,3-propanedithiol (0.5 mL) and triethylamine (0.4 mL) were added in sequence, and the mixture was stirred at room temperature for 12 hours. The reaction solution was directly concentrated under reduced pressure, and the concentrated crude product was redissolved in toluene (about 10 mL), concentrated under reduced pressure, and repeated twice.

[0143] The crude product obtained by concentration in the previous step was redissolved in pyridine (4.0 mL), and acetic anhydride (0.5 mL, 5.3 mmol) and 4-dimethylaminopyridine (5.0 mg, 0.04 mmol) were added in turn under ice bath, and reacted at room temperature for 4 hours. The reaction solution diluted with dichloromethane (30.0 mL) was washed with sodium bicarbonate solution (6.0 mL) and clean water (6.0 mL), and the organic phase was dried, filtered, concentrated, and quickly separated and purified by silica gel column.

[0144] The silicon elution product of the previous step was redissolved in tetrahydrofuran (3.0 mL), and water (1.0 mL) was added. Solid lithium hydroxide (50.0 mg, 2.09 mmol) was added under ice bath, and then the reaction solution was gradually heated to 35°C and stirred for 12 hours. A cation exchange resin was added under ice bath cooling to adjust the pH value to 8, and then the solution was filtered and concentrated under reduced pressure.

[0145] The concentrated product of the previous step was redissolved in tetrahydrofuran (2.0 mL), and water (2.0 mL) and palladium hydroxide / carbon (80.0 mg) were added, and hydrogen was added externally to exchange the air in the reaction solution, and the reaction was gradually heated to 30° C. under a hydrogen environment for 24 hours. After the reaction was complete, the reaction solution was filtered with diatomaceous earth, and the filtrate was lyophilized and concentrated under reduced pressure, and separated and purified by BioGel P-2 molecular exclusion chromatography column. The purified product aqueous solution was freeze-dried to obtain compound 4 (12.2 mg, 56%, white foam).

[0146] Compound 4:R f =0.30 (MeOH:H2O=5:1); 1H NMR(400MHz,D2O)δ5.02(d,J=3.6Hz,1H),4.75(d,J=8.4Hz,2H),4.22(d,J=2.8Hz,1H),4.14- 4.01(m,2H),3.95-3.81(m,4H),3.76-3.55(m,5H),3.54-3.46(m,2H),3.43(td,J=6.9,6.4,3. 3Hz,1H),3.38-3.30(m,1H),3.24(td,J=9.6,3.3Hz,1H),3.10(dt,J=12.9,5.4Hz,1H),3.02- 2.93(m,1H),2.88(dd,J=10.3,8.3Hz,1H),1.98(s,3H),1.97-1.93(m,1H),1.91-1.75(m,3H); 13 C NMR(101MHz,D2O)δ176.4,175.6,174.4,100.4,99.6,94.6,76.5,76.1,73.5,72.7,72.4,70.8 ,70.7,70.0,69.9,62.8,62.1,60.8,60.0,56.1,53.3,38.8,33.2,26.0,22.0; HRMS(ESI):m / z calcd for C 25 H 43 N3O 18 [M+H] + :674.2615,found:674.2613.

[0147] Example 5

[0148] Microarray detection of synthetic oligosaccharides.

[0149] The oligosaccharide solution synthesized in Example 2-4 was spotted on an NHS glass slide (Sur Modics, DN01-0025) using a chip spotter. After spotting, incubate overnight at 26°C and 55% humidity. Then soak the glass slide in solution B (50nM Na2HPO4, 100nM ethanolamine aqueous solution) at 50°C for 1 hour. Wash the glass slide 3 times with ultrapure water and centrifuge to dry. Use a PBS solution containing 3% BSA (w / v) and block overnight at 4°C. Wash once with PBST (PBS containing 0.1% tween), wash twice with PBS, and centrifuge to dry. Place the glass slide in a 16-well incubator (ProPlate). Add 120μL of a human serum sample diluted in a PBS solution of 1% BSA (w / v) at 1:50 (1 for human serum sample, 50 for PBS solution) to each well and incubate in a wet box at 37°C in the dark for 1 hour. Remove the sample, wash 3 times with PBST, add the secondary antibody diluted in 1% BSA (w / v) PBS solution at 1:400 (1 for secondary antibody, 400 for PBS solution), and incubate in a wet box at 37°C in the dark for 45 minutes. Remove the secondary antibody solution and wash 3 times with PBST. Wash with ultrapure water, centrifuge and dry, and scan with a chip scanner. Human serum samples came from 13 different patients (P1–P13).

[0150] Experimental results: After screening, compounds 1-4 can be recognized by IgG antibodies in most serum samples and can produce significantly higher levels than the negative control (a disaccharide fragment of Helicobacter pylori was used in this experiment). 1 As a negative control), compound 3 showed the most prominent performance in antibody recognition. These four oligosaccharide fragments all showed the potential to be used for the preparation of immune detection reagents or vaccines for certain serotype strains. Figure 7 .

[0151] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

[0152] References 1.Li,L.;Yin,X.-C.;Jiang,Y.-Y.;Xia,Y.-F.;Wang,X.;Li,J.;Li,H.;Qin,Y.;Yang,J.-S.,Chemical Synthesis of a Branched Nonasaccharide Fragment fromHelicobacter pylori Lipopolysaccharide.Org.Lett.2024,26,2103-2107. 2.Huang,J.S.;Huang,W.;Meng,X.;Wang,X.;Gao,P.C.;Yang,J.S.,Stereoselective Synthesis of a-3-Deoxy-D-manno-oct-2-ulosonic Acid(a-Kdo)Glycosides Using 5,7-O-Di-tert-butylsilylene-Protected Kdo EthylThioglycoside Donors.Angew.Chem.,Int.Ed.2015,54,10894-10898. 3.Yang,Y.;Oishi,S.;Martin,C.E.;Seeberger,P.H.,Diversity-orientedSynthesis of Inner Core Oligosaccharides of the Lipopolysaccharide ofPathogenic Gram-negative Bacteria.J.Am.Chem.Soc.2013,135,6262-6271. 4.Suzuki,K.;Ohtsuka,I.;Kanemitsu,T.;Ako,T.;Kanie,O.,Single-StepMultisyntheses of Glycosyl Acceptors:Benzylation of n-1 Hydroxyl Groups ofPhenylthio Glycosides of Xylose,Mannose,Glucose,Galactose,2-Azido-2-deoxy-glucose,and 2-Azido-2-deoxy-galactose.J.Carbohydr.Chem.2005,24,219-236. 5.Zhou,X.Y.;Li,L.X.;Zhang,Z.;Duan,S.C.;Huang,Y.W.;Luo,Y.Y.;Mu,X.D.;Chen,Z.W.;Qin,Y.;Hu,J.;Yin,J.;Yang,J.S.,Chemical Synthesis and AntigenicEvaluation of Inner Core Oligosaccharides from Acinetobacter baumanniiLipopolysaccharide.Angew.Chem.,Int.Ed.2022,61,e202204420.

Claims

1. A cell wall oligosaccharide fragment of Acinetobacter baumannii, characterized in that: A compound having a structure represented by formula (1), formula (2), formula (3) or formula (4) or a pharmaceutically acceptable salt thereof:

2. The Acinetobacter baumannii cell wall oligosaccharide fragment according to claim 1, characterized in that The compounds represented by the structures of formula (1), formula (2) and formula (3) have a Kdo-Kdo disaccharide fragment containing an alpha-(2→5) link; the compounds represented by the structures of formula (3) and formula (4) have a 4,7-branched Kdo skeleton.

3. The method for preparing the cell wall oligosaccharide fragment of Acinetobacter baumannii according to claim 1, characterized in that: The following steps are involved: S01: Compound 7 is used as the starting material, and compound 8 is reacted with the compound to obtain compound 6; The glycosidation reaction is to place the compound 7 and the compound 8 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; The temperature condition of the glycosylation reaction is -20°C to 0°C; S02: dissolving the compound 6 in dry tetrahydrofuran, and then mixing with a desiliconizing agent to obtain a compound 9 through a desiliconization reaction; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid or tetrabutylammonium fluoride; S03: Compound 9 and Compound 10 are subjected to a glycosylation reaction to obtain Compound 11; the glycosylation reaction is to place Compound 9 and Compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S04: The compound 11 is subjected to acid hydrolysis reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction in sequence to obtain a compound of formula (1).

4. The preparation method according to claim 3, characterized in that: The organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

5. The method for preparing the cell wall oligosaccharide fragment of Acinetobacter baumannii according to claim 1, characterized in that: The following steps are involved: S01: Compound 6 is used as the starting material, dissolved in dry methanol, and sodium methoxide is added to obtain compound 12 through debenzoylation reaction; S02: Compound 12 and Compound 13 are subjected to a glycosylation reaction to obtain Compound 14; the glycosylation reaction is to place Compound 12 and Compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S03: dissolving the compound 14 in dry tetrahydrofuran, mixing with a desiliconizing agent, and performing a desiliconization reaction to obtain a compound 15; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid, or tetrabutylammonium fluoride; S04: The compound 15 is sequentially subjected to acid hydrolysis reaction, reduction reaction, acetylation reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction to obtain a compound of formula (2).

6. The preparation method according to claim 5, characterized in that: The organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

7. The method for preparing the cell wall oligosaccharide fragment of Acinetobacter baumannii according to claim 1, characterized in that: The following steps are involved: S01: Compound 6 is used as the starting material, dissolved in dry methanol, and sodium methoxide is added to obtain compound 12 through debenzoylation reaction; S02: Compound 12 and Compound 13 are subjected to a glycosylation reaction to obtain Compound 14; the glycosylation reaction is to place Compound 12 and Compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S03: dissolving the compound 14 in dry tetrahydrofuran, mixing with a desiliconizing agent, and performing a desiliconization reaction to obtain a compound 15; the desiliconizing agent comprises one or more selected from triethylamine trihydrofluoric acid, pyridine hydrofluoric acid, or tetrabutylammonium fluoride; S04: Compound 15 and Compound 10 are subjected to a glycosylation reaction to obtain Compound 16; the glycosylation reaction is to place Compound 15 and Compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S05: The compound 16 is sequentially subjected to acid hydrolysis reaction, reduction reaction, acetylation reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction to obtain a compound of formula (3).

8. The preparation method according to claim 7, characterized in that: The organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

9. The method for preparing the cell wall oligosaccharide fragment of Acinetobacter baumannii according to claim 1, characterized in that: The following steps are involved: S01: Compound 7 is used as a starting material, and compound 5 is added to undergo a glycosylation reaction to obtain compound 17; the glycosylation reaction comprises placing compound 7 and compound 5 in an organic solvent, adding N-iodosuccinimide, and reacting under the action of an acidic reagent; the acidic reagent comprises one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; The temperature condition of the glycosylation reaction is -80°C to -45°C; S02: Compound 17 is dissolved in dry methanol, and sodium methoxide is added and then subjected to debenzoylation reaction to obtain compound 18; S03: Compound 18 and Compound 13 are subjected to a glycosylation reaction to obtain Compound 19; the glycosylation reaction is to place Compound 18 and Compound 13 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S04: dissolving the compound 19 in dry tetrahydrofuran, mixing with a desilication agent, and performing a desilication reaction to obtain a compound 20; the desilication agent comprises one or more selected from triethylamine trihydrofluoride, pyridine hydrofluoride, or tetrabutylammonium fluoride; S05: Compound 20 and compound 10 are subjected to a glycosylation reaction to obtain compound 21; the glycosylation reaction is to place compound 20 and compound 10 in an organic solvent, add N-iodosuccinimide, and react under the action of an acidic reagent; the acidic reagent includes one or more selected from trifluoromethanesulfonic acid, trimethylsilyl trifluoromethanesulfonate or trifluoromethanesulfonate; the temperature condition of the glycosylation reaction is -20°C to 0°C; S06: The compound 21 is subjected to reduction reaction, acetylation reaction, alkaline hydrolysis reaction and catalytic hydrogenation reaction in sequence to obtain a compound of formula (4).

10. The preparation method according to claim 9, characterized in that: The organic solvent includes one or more selected from dichloromethane, dichloroethane, ether or toluene.

11. Use of the Acinetobacter baumannii cell wall oligosaccharide fragment according to claim 1 in the preparation of a vaccine for preventing and / or treating Acinetobacter baumannii infection.

12. The use according to claim 11, characterized in that The terminal of the Acinetobacter mandshurica cell wall oligosaccharide fragment has a short chain with an amino group, which is used for conjugating a carrier protein.

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