A method for the preparation of A, B and Lewis blood group antigens

Abstract

This invention discloses a method for preparing A, B, and Lewis blood group antigens, wherein the A, B, and Lewis blood group antigens are specifically blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b Antigen. A one-pot photosensitive method was used to achieve blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b The method for obtaining large quantities of antigens, as described in this invention, features mild reaction conditions, shortened purification steps, simplicity, high efficiency, environmental friendliness, low cost, and high yield and purity of the target substance. This invention provides a practical and rapid chemical synthesis route for blood type A antigens. tri Antigen, B tri Antigen, Le a Antigen and Le b Antigens provide tools for the development of norovirus vaccines and related antibodies, and therefore have great application prospects.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry technology, and specifically relates to a method for preparing A, B and Lewis blood group antigens. Background Technology

[0002] The ABO(H) blood group system, the earliest discovered blood group system in humans, has glycans as the core structure of its antigens. Due to its unique structural features, it can bind to glycoproteins in a highly specific manner, playing a variety of important biological functions in immune regulation, cell recognition, signal transduction, and pathogen infection. As the application of the ABO(H) blood group system in the biomedical field continues to expand, the demand for related research has increased significantly, and these studies have a huge need for structurally defined tissue blood group antigens.

[0003] The results indicate that structurally defined tissue blood group antigens play an irreplaceable biological role in key medical areas such as immune response regulation, transplant rejection, pathogenic mechanisms, and clinical blood transfusion. To further explore the important role of these antigens in the medical field, it is necessary to develop sufficient quantities of blood group antigens for in-depth research on the ABO(H) blood group system.

[0004] Existing research literature 1 (Huang, P.; Farkas, T.; Marionneau, S.; Zhong, W.; Ruvoën-Clouet, N.; Morrow, AL; Altaye, M.; Pickering, LK; Newburg, DS; LePendu, J.; Jiang, X. Noroviruses Bind to Human ABO, Lewis, and SecretorHisto-Blood Group Antigens: Identification of 4 Distinct Strain-Specific Patterns). J. Infect. Dis. 2003, 188(1), 19-31.), Document 2 (Huang, P.; Farkas, T.; Zhong, W.; Tan, M.; Thornton, S.; Morrow, AL; Jiang, X. Norovirus andHisto-Blood Group Antigens: Demonstration of a Wide Spectrum of StrainSpecificities and Classification of Two Major Binding Groups among MultipleBinding Patterns. J. Virol. 2005, 79 (11), 6714-6722.), Document 3 (Tan, M.; Jiang, X. Norovirus and Its Histo-Blood Group Antigen Receptors: An Answer to a Historical Puzzle. Trends Microbiol. 2005, 13 (6), 285-293.), Document 4 (Tan, M.; Jiang, X. Norovirus-Host Interaction: Multi-Selections by Human Histo-BloodGroup Antigens. Trends Microbiol. 2011, 19 (8), 382-388.) and reference 5 (Tan, M.; Jiang, X. Histo-Blood Group Antigens: A Common Niche for Norovirus and Rotavirus). Expert Rev. Mol. Med. 2014, 16 (e5.) The results showed that blood type A tri Antigen, B tri Antigen, Le a Antigen and Le b Antigen (chemical structural formula see) Figure 1 These methods can be used to evaluate the binding ability of norovirus to blood group antigens and can serve as a molecular tool for the development of norovirus vaccines and related antibodies. However, the preparation methods for these blood group antigens are cumbersome, have low yields, and are costly, thus limiting their large-scale application. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide an A, B, and Lewis blood group antigen, specifically blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b The method for preparing antigens is characterized by its simplicity, low cost, environmental friendliness, and high yield.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing A, B, and Lewis blood group antigens, wherein the blood group antigens include blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b The antigen has the following chemical structural formula: ; Includes the following steps: (1) Blood type A tri Preparation of antigens: A11, 4,6-benzylene protection, 3-photosensitive protecting group ( o The NBC-protected galactose receptor 5 and the all-benzyl-protected fucosylate donor 6 undergo a first glycosylation reaction to yield a disaccharide protected with a photosensitive protecting group. The photosensitive protecting group is then removed by light irradiation, generating an in-situ hydroxyl-exposed disaccharide receptor. This receptor then undergoes a second glycosylation reaction with the 2-azide-, 3,4,6-acetyl-protected trichloroacetylimine ester donor 7 to yield A. tri Trisaccharide antigen backbone 8; A12, A tri The azide group of the trisaccharide antigen backbone 8 is reduced to an amino group, followed by an acetylamino protection reaction, then the benzoyl group is removed by saponification, and then A is... tri The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 8 undergo a reductive removal reaction to obtain blood type A. tri Antigen; its synthetic route is as follows: ; (2) B tri Preparation of antigens: B21, 4,6-benzylene protection, 3-photosensitive protecting group ( o The NBC-protected galactose receptor 5 and the fully benzyl-protected fucosylate donor 6 undergo a first glycosylation reaction to yield a disaccharide protected with a photosensitive protecting group. Upon photoirradiation, the photosensitive protecting group is removed, generating an in-situ hydroxyl-exposed disaccharide receptor. This receptor then undergoes a second glycosylation reaction with the fully benzyl-protected galactosesylate donor 9 to yield B. tri Trisaccharide antigen backbone 10; B22, B tri The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 10 undergo a reductive removal reaction to yield B. tri Antigen; its synthetic route is as follows: ; (3) Le a Preparation of antigens: L31. A galactosidase donor 11 protected with a photosensitive protecting group (oNBC) and a glucose acceptor 12 protected with a trichloroacetyl group at position 2 and a 4,6-benzyl group are glycosylated to obtain a disaccharide 13. L32. The disaccharide 13 is subjected to a selective reduction ring-opening reaction to obtain a product containing a photosensitive protecting group ( o NBC) protected disaccharide receptor 14; L33, containing photosensitive protective groups ( o The NBC-protected disaccharide receptor 14 undergoes glycosylation with the all-benzyl-protected fucosinolate donor 15 to yield Le a Trisaccharide antigen backbone 16; L34. Benzoyl, acetyl, and o-nitrobenzyloxycarbonyl groups are removed through a saponification reaction, and then Le... a The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 16 undergo a reductive removal reaction to yield Le. a The antigen, and its synthetic route are as follows: ; (4) Le b Preparation of antigens: L41, The photosensitive protective group obtained in step L32 ( o The NBC-protected disaccharide acceptor 14 and the fully benzyl-protected fucosinolate donor 15 undergo a first glycosylation reaction to yield a trisaccharide protected with a photosensitive protecting group. Upon photoirradiation, the photosensitive protecting group is removed, generating an in-situ hydroxyl-exposed trisaccharide acceptor. This acceptor then undergoes a second glycosylation reaction with the fully benzyl-protected fucosinotrifluorophenylacetylimine ester donor 17 to yield Le. b Tetrasaccharide antigen backbone 18; L42, benzoyl and acetyl groups are removed through a saponification reaction, and then Le... b The benzyl and benzyloxycarbonyl groups of the tetrasaccharide antigen backbone 18 undergo a reductive removal reaction to yield Le. b The antigen, and its synthetic route are as follows: .

[0007] Preferably, in steps A11, B21, and B41, the catalyst for the first glycosylation reaction is any one of Ph3PAuOTf, Ph3PAuNTf2, SPhosAuOTf, SPhosAuNTf2, NIS / TMSOTf, NIS / TBSOTf, and NIS / TfOH; the solvent for the first glycosylation reaction is dichloromethane or toluene; and molecular sieves are used to remove water in the first glycosylation reaction.

[0008] Preferably, in step A11, the 4,6-benzylene protection group and the 3-photosensitive protection group ( o The molar ratio of NBC-protected galactose receptor 5, fully benzyl-protected fucosylate donor 6, and catalyst for the first glycosylation reaction is 1:1.2~2:0.5~1.0.

[0009] Preferably, in step A11, the catalyst for the second glycosylation reaction is one or a combination of two or more of TMSOTf, TBSOTf, TfOH, and BF3·Et2O, and the molar ratio of the galactose acceptor 5, the trichloroacetylimine ester donor 7, and the catalyst for the second glycosylation reaction is 1:4~6:1.5~2.0.

[0010] Preferably, in step A12, the reagent for the acetylamino protection reaction is acetyl chloride or acetic anhydride, more preferably acetic anhydride; the molar ratio of the Atri trisaccharide antigen backbone 8 to the reagent for the acetylamino protection reaction is 1:15~20.

[0011] Preferably, in step A12, the solvent for the acetylamino protection reaction is a mixed solution of dichloromethane and methanol, and the volume ratio of dichloromethane to methanol is (0.1~0.2):1.

[0012] Preferably, in step A12, the reaction system for reducing the azide group to an amino group comprises: zinc powder as a reducing agent, acetic acid, triphenylphosphine, 1,3-propanedithiol, and tetrahydrofuran as solvents. tri The molar ratio of the trisaccharide antigen backbone 8, zinc powder, and acetic acid is 1:45~100:25~50.

[0013] Preferably, in step B21, the 4,6-benzylene protection group and the 3-photosensitive protection group ( o The molar ratio of NBC-protected galactose receptor 5, fully benzyl-protected fucosylate donor 6, and catalyst for the first glycosylation reaction is 1:1.2~2:0.5~1.0.

[0014] Preferably, in step B21, the 4,6-benzylene protection group and the 3-photosensitive protection group ( oThe molar ratio of NBC-protected galactose receptor 5, galactosyl ester donor 9, and catalyst for the second glycosylation reaction is 1:2~4:1.0~2.0.

[0015] Preferably, in steps A11 and B21, the photo-irradiation reaction to remove the photosensitive protective group is carried out under a 300-400 nm ultraviolet lamp for 0.5-1 h.

[0016] Preferably, in step L31, the catalyst for the glycosylation reaction is NIS / TfOH, and the molar ratio of the galactosidoside donor 11, glucose acceptor 12, and NIS, TfOH is 1:1.2~3:2~6:0.1~1.0.

[0017] Preferably, in step L32, the reduction system for the selective reduction ring-opening reaction is any one of NaBH3CN (sodium cyanoborohydride) / HCl, NaBH3CN / tetrafluoroboric acid-diethyl ether complex, NaBH3CN / TFA, NaBH3CN / BF3·Et2O, Et3SiH (triethylsilane) / HCl, Et3SiH / tetrafluoroboric acid-diethyl ether complex, Et3SiH / TFA, and Et3SiH / BF3·Et2O, more preferably NaBH3CN / tetrafluoroboric acid-diethyl ether complex; the molar ratio of the galactosothioglycoside donor 11 protected by the photosensitive protecting group (oNBC) and sodium cyanoborohydride to the tetrafluoroboric acid-diethyl ether complex is 1:30~50:30~50; and the solvent for the selective reduction ring-opening reaction is tetrahydrofuran.

[0018] Preferably, in step L33, the catalyst for the glycosylation reaction is NIS / TfOH, and the catalyst containing the photosensitive protecting group ( o The molar ratio of NBC-protected disaccharide receptor 14 to fully benzyl-protected fucosinolate donor 15, NIS, and TfOH is 1:1.2~2:2~6:0.1~1.0.

[0019] Preferably, in steps A12, L34, and L42, the solvent for the saponification reaction is a mixed solution of dichloromethane and methanol; the reagent for the saponification reaction is any one of sodium methoxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, more preferably sodium methoxide; A tri The molar ratio of the trisaccharide antigen backbone 8 to the reagent for the saponification reaction is 1:0.1~0.3; Le a The molar ratio of the trisaccharide antigen backbone 16 to the reagents for the saponification reaction is 1:0.3~50; the Le b The molar ratio of tetrasaccharide antigen backbone 18 to the reagent for saponification reaction is 1:0.2~50.

[0020] Preferably, in step L41, the catalyst for the first glycosylation reaction is NIS / TfOH, and the catalyst containing the photosensitive protecting group ( o The molar ratio of NBC-protected disaccharide receptor 14 to fully benzyl-protected fucosinolate donor 15, NIS, and TfOH is 1:1.2~2:2~6:0.1~1.0.

[0021] Preferably, in step L41, the catalyst for the second glycosylation reaction is one or a combination of two or more of TMSOTf, TBSOTf, TfOH, and BF3·Et2O; the molar ratio of the disaccharide acceptor 14, the fucose trifluorophenylacetylimine ester donor 17, and the catalyst for the second glycosylation reaction is 1:2~4:0.5~2.0.

[0022] Preferably, in step L41, the photosensitive protective group removal reaction is carried out under a 300-400 nm ultraviolet lamp for 1-3 hours.

[0023] Preferably, in steps A12, B22, L34 and L42, the reaction reagent for the reduction and removal reaction is one or more of palladium on carbon, palladium hydroxide on carbon, a mixture of palladium on carbon and palladium hydroxide on carbon (20%), and Raney nickel, more preferably palladium hydroxide on carbon (20%) or a combination of palladium on carbon and palladium hydroxide on carbon; the reduction and removal reaction is carried out under hydrogen conditions.

[0024] Preferably, in step A12, the A tri The molar ratio of the trisaccharide antigen backbone 8 to the reaction reagent for the reduction and removal reaction is 1:9~15; the solvent for the reduction and removal reaction is a mixed solution of tetrahydrofuran, water and acetic acid, and the volume ratio of tetrahydrofuran, water and acetic acid is (1.3~1.5):1:(0.05~0.06).

[0025] In step B22, the B tri The molar ratio of the trisaccharide antigen backbone 10 to the reaction reagent for the reduction and removal reaction is 1:30~40, and the solvent is a mixed solution of tetrahydrofuran, water and acetic acid, with a volume ratio of (1.3~1.5):1:(0.05~0.06).

[0026] In step L34, the Le a The molar ratio of the trisaccharide antigen backbone 16 to the reaction reagent for the reduction and removal reaction is 1:9~15. The solvent for the reduction and removal reaction is a mixed solution of methanol, tetrahydrofuran, water and acetic acid, and the volume ratio of methanol, tetrahydrofuran, water and acetic acid is (2~5):(1~3):1:(0.1~0.5). In step L42, the Le bThe molar ratio of the tetrasaccharide antigen backbone 18 to the reaction reagent for the reduction and removal reaction is 1:50~100:50~100; the solvent for the reduction and removal reaction is a mixed solution of methanol, tetrahydrofuran, water and acetic acid, and the volume ratio of methanol, tetrahydrofuran, water and acetic acid is (2~5):(1~3):1:(0.1~0.5).

[0027] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an A, B, and Lewis blood group antigen, specifically blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b The method for preparing the antigen employs a one-pot photosensitive process, which features mild reaction conditions, shortened purification steps, simplicity, high efficiency, environmental friendliness, low cost, and high yield and purity of the obtained compound. This method is suitable for blood type A antigen preparation. tri Antigen, B tri Antigen, Le a Antigen and Le b The large-scale acquisition of antigens provides a practical and rapid chemical synthesis route, which offers a tool for the development of norovirus vaccines and related antibodies, and therefore has great application prospects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 Blood type A tri Antigen 1, B tri Antigen 2, Le a Antigen 3 and Le b The structural formula of antigen 4; Figure 2 Blood type A tri Synthetic route diagram of antigen 1; Figure 3 For B tri Synthetic route diagram of antigen 2; Figure 4 For Le a Synthetic route diagram of antigen 3; Figure 5 For Le b Synthetic route diagram of antigen 4. Detailed Implementation

[0030] The technical solutions of this application will be further described in detail below with reference to the accompanying drawings and specific embodiments. In the following description, specific details such as particular system structures and technologies are set forth for illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art should understand that the present invention can also be implemented in other embodiments without these specific details.

[0031] Example 1 Reference Figure 2 One-pot photosensitive synthesis of blood type A tri Antigen 1: Protect 4,6-benzyl group and photosensitive group at position 3 ( o NBC-protected galactose receptor 5 (20.0 mg, 0.027 mmol), fully benzyl-protected fucosylate donor 6 (23.0 mg, 0.041 mmol), and newly activated 4 Å molecular sieve (50.0 mg) were placed in a quartz tube, and dry toluene (2.0 mL) was added. The mixture was stirred at -60 °C for 30 min under argon protection, and then freshly prepared Ph3PAuOTf solution in dichloromethane (135 mL) was slowly added. µ L, 0.1 M), stirred for 1 h at -60 ℃. TLC monitoring confirmed complete reaction of galactose receptor 5. The reaction system was then placed in a parallel light reactor and irradiated with 300 nm, 365 nm, and 400 nm UV lamps to remove the photoprotective group (L, 0.1 M). o NBC), and after 30 min, TLC monitoring confirmed complete removal of the photosensitizing protective group. The quartz tube was transferred to a regular magnetic stirrer, and freshly prepared 2-azide, 3,4,6-acetyl-protected trichloroacetylimine ester donor 7 (64.0 mg, 0.135 mmol) and freshly activated 4 Å molecular sieve (150 mg) were added at -20 °C. After stirring for 30 min, TMSOTf (4.84 mg) was added. μ L (0.027 mmol), stirred overnight at -20 °C. The disaccharide acceptor reaction was confirmed to be complete by TLC. After filtration through molecular sieves, the solution was concentrated under vacuum and purified by silica gel column chromatography (petroleum ether / ethyl acetate: 1.5 / 1) to obtain a yellow syrup, namely A. tri Trisaccharide antigen backbone 8 (16.6 mg, 300 nm light, 48% overall yield), (19.0 mg, 365 nm light, 55% overall yield), (17.3 mg, 400 nm light, 50% overall yield). [α] = +9.2 ( c 0.36, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.55 (d, J= 3.2 Hz, 2 H), 7.44 (d, J =7.2 Hz, 2 H), 7.39-7.27 (m, 19 H), 7.25-7.12 (m, 7 H), 5.57 (s, 1 H), 5.44-5.38 (m, 1 H), 5.33 (d, J = 3.2 Hz, 1 H), 5.28 (d, J = 10.8 Hz, 1 H), 5.24-5.15(m, 3 H), 5.13 (d, J = 12.0 Hz, 1 H), 4.93 (d, J = 12.0 Hz, 1 H), 4.89 (d, J = 12.0Hz, 1 H), 4.79 (d, J = 11.6 Hz, 1 H), 4.76-4.63 (m, 2 H), 4.61 (d, J = 11.6 Hz, 1H), 4.49-4.22 (m, 6 H), 4.17-4.08 (m, 3 H), 4.03-3.78 (m, 4 H), 3.72-3.61 (m,1 H), 3.58 (dd, J = 3.6, 11.2 Hz, 1 H), 3.53-3.20 (m, 5 H), 2.13-1.97 (m, 9 H),1.92-1.72 (m, 2 H), 1.03 (dd, J = 6.0, 18.0 Hz, 3 H); 13C NMR (150 MHz, CDCl3) δ170.5, 169.9, 169.6, 156.4, 139.5, 139.0, 138.9, 138.8, 137.7, 136.9, 128.9,128.7, 128.6, 128.5, 128.4, 128.3, 128.1, 128.0, 127.7, 127.6, 127.5, 127.4,126.2, 102.1, 100.8, 98.2, 94.1, 80.6, 77.8, 76.1, 74.9, 74.2, 72.8, HRMS (ESI) m / z calcd for C 70 H 78 N4O 19 Na [M + Na] + 1301.5158, found 1301.5162. A tri The trisaccharide antigen backbone 8 (37.0 mg, 0.029 mmol) was dissolved in dry tetrahydrofuran (1.0 mL), and then glacial acetic acid (46.0 mL) was added sequentially. µ L) and freshly activated zinc powder (91.2 mg) were stirred overnight at room temperature. TLC monitoring confirmed A tri After complete conversion of the trisaccharide antigen backbone 8, zinc powder was removed by filtration, followed by extraction with dichloromethane. The organic phase was treated with anhydrous sodium sulfate and then filtered. The filtrate was concentrated under vacuum to remove the solvent, yielding the target crude product. The crude product was dissolved in a mixed solvent of methanol and dichloromethane (V / V, 1.0 / 0.1, 1.1 mL), and triethylamine (200 mL) was added sequentially. µ L) and acetic anhydride (50.0) µL), stirred overnight at room temperature. Complete conversion of the starting material was confirmed by TLC. After removing the solvent from the reaction solution by vacuum concentration, silica gel column chromatography (dichloromethane / anhydrous methanol: 70 / 1→60 / 1) yielded colorless crystals. The product from the previous step and sodium methoxide (0.160 mg, 0.003 mmol) were dissolved in anhydrous methanol (0.5 mL) and stirred at room temperature for 5 h. Complete consumption of the starting material was confirmed by TLC. Hydrogen ion exchange resin was added to the system to neutralize the pH. The resin was removed by filtration, and the filtrate was concentrated under vacuum to obtain white crystals, which were then added to the next step. The product was dissolved in a mixed solvent of tetrahydrofuran and water (V / V, 4.5 / 3.4, 7.9 mL), and AcOH (200...) was added sequentially. µ L) and 20% Pd(OH)2 / C (40.0 mg), purged with hydrogen several times, and stirred at room temperature for 1 day. Complete conversion of the starting material was confirmed by TLC. The catalyst was filtered off, and the solvent in the filtrate was removed by vacuum concentration. The filtrate was then purified by LH-20 gel column chromatography (methanol / water: 3 / 1) to obtain a colorless syrup, i.e., blood type A. tri Antigen 1 (10.0 mg, total yield 59%). 1 H NMR (400 MHz, D2O) δ 5.29 (d, J = 3.2 Hz, 1 H), 5.18 (d, J = 3.6 Hz, 1 H), 4.57 (d, J = 8.0 Hz, 1H), 4.37 (q, J = 6.8 Hz, 1 H), 4.28-4.21 (m, 3 H), 4.04-3.94 (m, 4 H), 3.93-3.83 (m, 3 H), 3.82-3.79 (m, 3 H), 3.78-3.75 (m, 3 H), 3.67 (dd, J = 4.4, 7.6Hz, 1 H), 3.14 (t, J = 7.2 Hz, 2 H), 2.05 (s, 3 H), 2.03-1.98 (m, 2 H), 1.24(d, J = 6.8 Hz, 3 H); HRMS (ESI) m / z calcd for C 23 H 43 N2O 15 [M + H] + 587.2663, found 587.2662. This result is consistent with the literature ( Glycoconj. J 2016, 33The spectral data of , 63) are consistent, therefore it is determined to be blood type A of the target product. tri antigen.

[0032] Example 2 Reference Figure 3 Photosensitive one-pot synthesis of B tri Antigen 2: The 4,6-benzyl group is protected, and the 3-photosensitive protecting group is added ( o NBC-protected galactose receptor 5 (20.0 mg, 0.027 mmol), fully benzyl-protected fucosylate donor 6 (23.0 mg, 0.041 mmol), and newly activated 4 Å molecular sieve (50.0 mg) were placed in a quartz tube, and dried toluene (2.0 mL) was added. The mixture was stirred at -60 °C for 30 min under argon protection, and then freshly prepared Ph3PAuOTf CH2Cl2 solution (135 mL) was added. µ L, 0.1 M), continued stirring, and after 1 h, TLC showed that the reaction was complete. Irradiation under 300 nm, 365 nm and 400 nm UV lamps for 30 min each showed that the photosensitive protecting group was completely removed by TLC. The quartz tube was transferred to -60 ℃, and under argon protection, 4 Å molecular sieve (100 mg) and fully benzyl-protected galactosynthetic ester donor 9 (54.6 mg, 0.081 mmol) were added. After stirring for 30 min, freshly prepared Ph3PAuOTf CH2Cl2 solution (270 L) was added. µ L, 0.1 M), stirred overnight, TLC showed complete reaction, the reaction solution was filtered, concentrated, and the crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate: 3 / 1) to give a pale yellow oily product, namely B. tri Trisaccharide antigen backbone 10 (24.1 mg, 300 nm light, 60% overall yield), (27.3 mg, 365 nm light, 68% overall yield), (25.3 mg, 400 nm light, 63% overall yield). [α] = -11.6 (c 0.57, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.44 (d, J = 7.6Hz, 2 H), 7.36-7.31 (m, 7 H), 7.29-7.26 (m, 14 H), 7.25-7.21 (m, 12 H), 7.18-7.17 (m, 7 H), 7.15-7.13 (m, 3 H), 7.11-7.09 (m, 3 H), 7.02 (d, J= 6.8 Hz, 2H), 5.54-5.48 (m, 1 H), 5.42 (s, 1 H), 5.36 (d, J = 3.2 Hz, 1 H), 5.18-5.15 (m,2 H), 4.89 (d, J = 11.6 Hz, 1 H), 4.84 (d, J = 11.6 Hz, 1 H), 4.78-4.74 (m, 1 H),4.70-4.60 (m, 4 H), 4.58-4.53 (m, 2 H), 4.50-4.40 (m, 4 H), 4.38-4.31 (m, 5H), 4.24-4.18 (m, 3 H), 4.12-4.04 (m, 2 H), 4.00-3.92 (m, 4 H), 3.89-3.83 (m,2 H), 3.73-3.63 (m, 1 H), 3.51-3.47 (m, 1 H), 3.43-3.25 (m, 4 H), 3.15-3.03(m, 2 H), 1.95-1.70 (m, 2 H), 1.09-1.02 (m, 3 H); 13 C NMR (150 MHz, CDCl3) δ156.3, 139.2, 139.1, 139.0, 138.9, 138.8, 138.7, 138.6, 138.1, 137.8, 137.1,137.0, 136.9, 129.0, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 128.1, 128.0,127.9, 127.8, 127.7, 127.6, 127.5, 127.4, 127.3, 127.2, 126.5, 124.6, 124.2,119.3, 102.3, 101.2, 97.7, 92.5, 80.1, 78.2, 78.1, 76.7, 76.5, 75.8, 75.6,75.0, 74.6, 73.9, 73.2, 73.1, 72.7, 72.2, 71.3, 70.1, 69.5, 67.3, 66.9, 66.4,66.2, 51.2, 50.9, 44.7, 30.4, 16.8; HRMS (ESI) m / z calcd for C 92 H 97 NO17 Na [M +Na] + 1510.6654, found 1510.6655. B tri The trisaccharide antigen backbone 10 (30.0 mg, 0.02 mmol) was dissolved in a THF / H2O mixed solvent (V / V, 9.1 / 7.0, 16.1 mL), and AcOH (400 mg / mL) was added sequentially. μ L) and 20% Pd(OH)2 / C (100 mg), purged with hydrogen 5 times, stirred at room temperature for 24 h, TLC monitoring showed that the starting material reacted completely, filtered and directly concentrated under reduced pressure, purified by LH-20 gel column chromatography (methanol / water: 4 / 1) to obtain a light yellow foamy substance, i.e. B tri Antigen 2 (10.8 mg, 99%). 1 H NMR (400 MHz, D2O) δ5.26 (d, J = 8.0 Hz, 2 H), 4.59 (d, J = 8.0 Hz, 1 H, H-1β), 4.40-4.32 (m, 1 H), 4.28-4.24 (m, 2 H), 3.99 (br s, 3 H), 3.90-3.86 (m, 3 H), 3.83-3.80 (m, 6 H), 3.75-3.74 (m, 3 H), 3.15 (t, J = 6.8 Hz, 2 H), 2.06-1.97 (m, 2 H), 1.23 (d, J =6.8 Hz, 3 H); HRMS (ESI) m / z calcd for C 21 H 40 NO 15 [M + H] + 546.2398, found 546.2399. This result is consistent with the literature ( Glycoconj. J 2016, 33 The spectral data of , 63) are consistent, therefore it is determined to be the target product B. tri antigen.

[0033] Example 3 Reference Figure 4 Synthesize Le a Antigen 3: Anhydrous toluene (2.0 mL) was added to galactosidoside donor 11 (68.2 mg, 0.09 mmol) protected with an oNBC photoprotective group, glucose receptor 12 (34.6 mg, 0.05 mmol) protected with a trichloroacetyl group at position 2 and a 4,6-benzyl group, and activated 4 Å molecular sieve (110 mg). The mixture was stirred at 0 ºC for 30 min under argon protection. Then, NIS (33.7 mg, 0.15 mmol) and TfOH (1.33 mg) were added. µ L, 0.015 mmol), stirred at room temperature for 2 h. After TLC showed complete reaction, an appropriate amount of Et3N was added to quench the reaction, the molecular sieve was removed by filtration, the filtrate was washed with saturated Na2S2O3 solution, extracted three times with CH2Cl2, the organic phases were combined, washed successively with saturated NaHCO3 solution and saturated NaCl solution, and dried over anhydrous Na2SO4. The drying agent was removed by filtration, the concentration was increased, and the product was purified by silica gel column chromatography (petroleum ether / ethyl acetate: 2.5 / 1) to obtain white foam, i.e. disaccharide 13 (55.8 mg, 88%). [α] = +16.4 ( c 1.04, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.96 (d, J = 7.6 Hz, 1 H), 7.86 (d, J =7.2 Hz, 2 H), 7.52 (t, J = 7.6 Hz, 1 H), 7.47 (d, J = 6.8 Hz, 2 H), 7.41-7.11 (m,25 H), 5.59 (d, J = 2.8 Hz, 1 H), 5.53 (s, 1 H), 5.44 (t, J = 9.6 Hz, 1 H), 5.36-5.30 (m, 1 H), 5.25-5.13 (m, 4 H), 4.98 (br s, 1 H), 4.82 (br s, 1 H), 4.55(d, J = 16.0 Hz, 2 H), 4.49-4.40 (m, 2 H), 4.32-4.26 (m, 2 H), 3.87 (br s, 1H), 3.78 (t, J = 6.4 Hz, 1 H), 3.71 (br s, 2 H), 3.60-3.46 (m, 3 H), 3.44 (d, J=6.4 Hz, 2 H), 3.29 (s, 1 H), 1.97 (s, 3 H), 1.87-1.75 (m, 2 H). 13 C NMR (150MHz, CDCl3) δ 169.9, 165.3, 162.3, 154.2, 147.1, 138.0, 137.6, 134.0, 133.6,129.8, 129.2, 129.1, 128.8, 128.7, 128.6, 128.3, 128.2, 128.1, 128.0, 127.5,127.3, 126.3, 125.1, 101.3, 99.9, 99.7, 99.4, 92.5, 92.4, 79.6, 76.8, 76.4,74.1, 73.7, 72.2, HRMS (ESI) m / z calcd forC 63 H 62 Cl3N3O 19 Na [M + Na] + 1292.2941, found 1292.2938. Disaccharide 13 (317 mg, 0.25 mmol) and sodium cyanoborohydride (628 mg, 10 mmol) were dissolved in dry tetrahydrofuran (3.0 mL), and the mixture was kept under argon protection at 0 °C. A tetrafluoroborate-diethyl ether complex (1.18 mL, 8.75 mmol) was added, and the mixture was stirred at room temperature for 3 h. The reaction solution was diluted with ethyl acetate, quenched with saturated NaHCO3 solution, extracted with ethyl acetate, washed with saturated NaCl solution, dried over anhydrous sodium sulfate, filtered, concentrated under vacuum, and subjected to silica gel column chromatography (petroleum ether / ethyl acetate: 1.5 / 1) to give a white solid containing a photosensitizing protecting group. o NBC) protected disaccharide receptor 14 (206 mg, 65%). [α] = +6.6 ( c 0.54, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.95 (s, 1 H), 7.87(d, J = 7.6 Hz, 2 H), 7.53 (t, J= 7.2 Hz, 1 H), 7.43-7.19 (m, 25 H), 7.16 (s, 1H), 5.61 (d, J = 2.8 Hz, 1 H), 5.48 (br s, 2 H), 5.29-5.09 (m, 4 H), 4.84 (t, J =8.8 Hz, 1 H), 4.67 (t, J = 6.8 Hz, 1 H), 4.61-4.50 (m, 4 H), 4.49-4.36 (m, 2H), 4.35-4.18 (m, 1 H), 4.03 (t, J = 6.0 Hz, 1 H), 3.98-3.80 (m, 3 H), 3.70(dd, J = 5.2, 10.8 Hz, 1 H), 3.65-3.54 (m, 2 H), 3.54-3.40 (m, 5 H), 3.29 (s, 2H), 2.00 (s, 3 H), 1.87-1.73 (s, 2 H). 13 C NMR (150 MHz, CDCl3) δ 169.9, 165.3,154.3, 138.1, 137.3, 134.0, 133.7, 129.9, 128.9, 128.8, 128.7, 128.5, 128.2,128.0, 127.8, 127.7, 127.5, 100.9, 98.9, 98.6, 83.0, 75.6, 75.5, 73.9, 73.7,73.6, 72.8, 72.0, 69.7, 67.6, 67.5, 67.4, 66.8, 58.7, 58.2, 50.7, 44.5, 44.0,29.9, 26.7, 20.6. HRMS (ESI) m / z calcd for C 63 H 64 Cl3N3O 19 Na [M + Na] + 1294.3097, found 1294.3094. Towards photosensitive protective groups ( oNBC-protected disaccharide receptor 14 (191 mg, 0.150 mmol), fully benzyl-protected fucosinolate donor 15 (161 mg, 0.270 mmol), and activated 4 Å molecular sieve (400 mg) were added to dry toluene (9.0 mL), stirred at 0 ºC for 30 min under argon protection, and then NIS (101 mg, 0.450 mmol) and TfOH (4.0 mL) were added. µ L, 0.045 mmol), stirred overnight at room temperature. After TLC showed complete reaction, an appropriate amount of Et3N was added to quench the reaction, the molecular sieve was removed by filtration, the filtrate was washed with saturated Na2S2O3 solution, extracted three times with CH2Cl2, the organic phases were combined, washed successively with saturated NaHCO3 solution and saturated NaCl solution, and dried over anhydrous Na2SO4. The drying agent was removed by filtration, the concentration was increased, and the product was purified by silica gel column chromatography (petroleum ether / ethyl acetate: 2 / 1) to obtain a white foamy solid, namely Le a Trisaccharide antigen backbone 16 (236 mg, 93%). [α] = -6.6 ( c 0.42,CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.90 (s, 1 H), 7.87 (d, J = 7.6 Hz, 2 H), 7.53(t, J = 7.6 Hz, 1 H), 7.48 (s, 1 H), 7.39-7.33 (m, 11 H), 7.31-7.27 (m, 9 H), 7.26-7.22 (m, 12 H), 7.20-7.17 (m, 4 H), 7.17-7.11 (m, 3 H), 5.66 (d, J = 1.6Hz, 1 H), 5.56-5.37 (m, 2 H), 5.14-5.08 (m, 4 H), 5.07-4.91 (m, 2 H), 4.80(d, J = 11.2 Hz, 2 H), 4.76-4.64 (m, 4 H), 4.62 (d, J = 11.2 Hz, 2 H), 4.56 (d, J =10.8 Hz, 1 H), 4.53-4.48 (m, 1 H), 4.48-4.32 (m, 5 H), 4.28 (d, J = 12.0 Hz, 1H), 4.09 (dd, J= 3.6, 10.0 Hz, 1 H), 3.90 (d, J = 11.2 Hz, 1 H), 3.88-3.74 (m, 4H), 3.63- 3.53 (m, 3 H), 3.46 (d, J = 9.2 Hz, 1 H), 3.35 (t, J = 8.0 Hz, 2 H), 3.28-3.00 (m, 2 H), 1.84-1.72 (m, 2 H), 1.70 (s, 3 H), 1.26-1.22 (d, J = 6.4Hz, 3 H). 13 C NMR (150 MHz, CDCl3) δ 169.4, 165.3, 162.2, 138.8, 138.7, 138.5,138.0, 137.4, 134.1, 133.6, 129.9, 129.1, 128.7, 128.6, 128.5, 128.2, 128.1,128.0, 127.9, 127.9, 127.8, 127.6, 127.5, 127.4, 125.2, 100.6, 97.5, 85.0,80.9, 76.2, 74.8, 74.7, 74.4, 73.9, 73.7, 73.6, 73.3, 72.9, 72.6, 71.9, 67.9,67.6, 67.4, 67.2, 66.8, 66.5, 51.1, 50.7, 44.6, 44.0, 29.9, 20.5, 17.1, 17.0.HRMS (ESI) m / z calcd for C 90 H 92 Cl3N3O 23 Na [M + Na] + 1710.5085, found 1710.5112. Le a The trisaccharide antigen backbone 16 (151 mg, 0.0896 mmol) was dissolved in CH2Cl2 and methanol (V / V, 6.8 / 3.2, 10.0 mL), and NaOMe (173 mg, 3.20 mmol) was added. The mixture was stirred overnight at room temperature. TLC monitoring showed that the starting material reacted completely. The reaction solution was purified by H2S. +The pH of the resin system was adjusted to neutral. The filtrate was collected by filtration and concentrated under reduced pressure. It was then purified by silica gel column chromatography (petroleum ether / ethyl acetate: 1 / 2) to obtain a colorless oily liquid (72.8 mg, 60%). The colorless oily liquid (35.0 mg, 0.0257 mmol) was dissolved in a mixed solvent of MeOH, THF, and H₂O (V / V / V, 7.1 / 5.2 / 2.4, 14.7 mL). AcOH (800 mL) was then added sequentially. μ The mixture was prepared by reacting 10% Pd / C (78.8 mg) and 20% Pd(OH)2 / C (78.8 mg) with hydrogen purging five times, stirring at room temperature for 48 h, filtering, and then directly concentrating under reduced pressure. The resulting product was purified by C18 reversed-phase column chromatography (anhydrous methanol / water: 1 / 9) to obtain a colorless syrup, which was the target product Le. a Antigen 3 (13.0 mg, 86%). [α] = -27.7 ( c 0.25, H2O); 1 HNMR (400 MHz, D2O) δ 5.03 (d, J = 3.6 Hz, 1 H), 4.88 (q, J = 6.8 Hz, 1 H), 4.53(d, J = 8.4, 1 H), 4.52 (d, J = 7.6, 1 H), 4.12-4.05 (m, 1 H), 4.05-3.95 (m, 2H), 3.95-3.88 (m, 3 H), 3.88-3.77 (m, 3 H), 3.77-3.67 (m, 4 H), 3.64 (dd, J =3.2, 9.6 Hz, 1 H), 3.61-3.55 (m, 2 H), 3.54-3.46 (m, 1 H), 3.10 (t, J = 6.8 Hz, 2 H), 2.06 (s, 3 H), 1.99-1.94 (m, 2 H), 1.19 (d, J = 6.4 Hz, 3 H). 13C NMR (150MHz, D2O) δ 174.5, 102.8, 101.1, 98.1, 76.0, 75.4, 74.8, 72.4, 72.3, 71.9,70.5, 69.1, 68.3, 67.9, 67.8, 66.9, 61.6, 59.6, 55.7, 37.6, 26.7, 23.3, 22.3,15.4. HRMS (ESI) m / z calcd for C 23 H 43 N2O 15 [M + H] + 587.2663, found 587.2666. Example 4 Reference Figure 5 Photosensitive one-pot synthesis of Le b Antigen 4: Containing photosensitive protective groups ( o NBC-protected disaccharide receptor 14 (14.0 mg, 0.011 mmol), fully benzyl-protected fucosinolate donor 15 (11.8 mg, 0.0198 mmol), and newly activated 4 Å molecular sieve (30.0 mg) were placed in a quartz tube, and dry toluene (1.0 mL) was added. The mixture was stirred at room temperature for 30 min under argon protection, and NIS (7.4 mg, 0.033 mmol) and TfOH (0.39 mg) were added at 0 °C. µ L (0.0044 mmol), stirred at room temperature. After 1 h, TLC showed complete reaction. Irradiation under 300 nm, 365 nm, and 400 nm UV lamps for 1 h each showed complete removal of the photosensitive protecting group by TLC. The quartz tube was transferred to a regular stirrer, and under argon protection, 4 Å molecular sieve (100 mg) and fully benzyl-protected fucose trifluorophenylacetylimine ester donor 17 (20.0 mg, 0.033 mmol) were added, and stirred for 30 min. TfOH (0.78) was added at 0 ℃. µ L (0.0088 mmol), stirred at room temperature for 3 h, TLC showed complete reaction. Et3N was quenched to neutral, the reaction solution was filtered, concentrated, and the crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate: 5 / 1) to give a pale yellow oily product, namely Le b Tetrasaccharide antigen backbone 18 (8.7 mg, 300 nm, 41% overall yield), (10.3 mg, 365 nm, 49% overall yield), (9.5 mg, 400 nm, 45% overall yield). [α] = -29.8 (c 0.63, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.70 (td, J =8.4, 22.8 Hz, 2 H), 7.45 (t, J = 7.2 Hz, 1 H), 7.35-7.07 (m, 50 H), 6.95 (br s,1 H), 6.82 (d, J = 6.0 Hz, 1 H), 5.61-5.28 (m, 2 H), 5.19-4.92 (m, 5H), 4.89-4.75 (m, 3 H), 4.74-4.52 (m, 8 H), 4.50-4.33 (m, 6 H), 4.32-4.16 (m, 4 H),4.15-4.00 (m, 3 H), 3.98 - 3.64 (m, 9 H), 3.59 (t, J = 9.6, 2 H), 3.52-3.27 (m,4 H), 3.20 (br s, 1 H), 2.95 (dd, J = 6.0, 12.8 Hz, 1 H), 1.72-1.66 (m, 2 H),1.62 (s, 3 H), 1.31 (d, J = 5.6 Hz, 3 H), 1.19 (d, J = 5.6 Hz, 3 H). 13C NMR (150MHz, CDCl3) δ 169.4, 139.1, 138.9, 138.8, 138.5, 138.4, 137.6, 129.7, 129.4,128.8, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 128.1, 128.0, 127.9, 127.8,127.7, 127.6, 127.3, 127.2, 126.9, 101.8, 100.0, 98.7, 98.4, 97.9, 92.7,92.1, 81.0, 79.4, 77.9, 76.4, 75.0, 74.9, 74.4, 73.6, 73.3, 73.1, 72.9, 72.7,72.6, 72.3, 68.2, 67.9, 67.6, 67.5, 66.9, 66.7, 66.6, 50.4, 43.7, 29.9, 27.5,20.6, 17.2, 16.5. MALDI-TOF MS m / z [M + Na] + calcd for C 109 H 115 Cl3N2O 23 Na 1948.689, found 1948.772. Le b Tetrasaccharide antigen backbone 18 (27.2 mg, 0.014 mmol) was dissolved in dichloromethane and methanol (V / V, 1.1 / 0.52, 1.62 mL), and sodium methoxide (28.1 mg, 0.52 mmol) was added. The mixture was stirred at room temperature for 2 h. After TLC confirmation that the starting material had been completely consumed, hydrogen ion exchange resin was added to neutralize the pH to neutral. The resin was removed by filtration, and the filtrate was concentrated under vacuum. The crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate: 2 / 1) to obtain a colorless oily product (15.3 mg, 61%). The product from the previous step (30.1 mg, 0.0169 mmol) was dissolved in a mixed solvent of methanol, tetrahydrofuran, and water (V / V / V, 10.8 / 7.9 / 3.6, 22.3 mL). AcOH (1.2 mL), 10% Pd / C (120 mg), and 20% Pd(OH)₂ / C (120 mg) were added sequentially. The mixture was purged with hydrogen several times and stirred at room temperature for 48 h. The product was then purified by C18 reversed-phase silica gel column chromatography (methanol / water: 1 / 9) to obtain a colorless syrup product, Le. b Antigen 4 (8.7 mg, 70%). [α] = -97.6 (c 0.09, H2O); 1 H NMR (400MHz, D2O) δ 5.17 (d, J = 3.6 Hz, 1 H), 5.02 (d, J = 3.6 Hz, 1 H), 4.87 (q, J = 6.4Hz, 1 H), 4.67 (d, J = 7.6 Hz, 1 H), 4.42 (d, J = 8.4 Hz, 1 H), 4.33 (q, J = 6.8Hz, 1 H), 4.14 (t, J = 10.0 Hz, 1 H), 4.04-3.96 (m, 2 H), 3.94 (dd, J = 3.2, 10.8Hz, 1 H), 3.91-3.85 (m, 2 H), 3.84-3.80 (m, 4 H), 3.78-3.73 (m, 4 H), 3.73-3.65 (m, 3 H), 3.64-3.51 (m, 3 H), 3.07 (t, J = 7.2 Hz, 2 H), 2.09 (s, 3 H), 1.99-1.92 (m, 2 H), 1.27 (d, J = 4.4 Hz, 6 H). 13 C NMR (150 MHz, D2O) δ 173.8,101.8, 100.6, 99.5, 97.9, 76.4, 75.4, 74.8, 74.5, 73.6, 72.1, 72.0, 71.9,69.5, 69.1, 68.7, 68.3, 67.9, 67.8, 67.1, 66.2, 61.6, 59.5, 55.6, 37.4, 26.7,22.2, 15.3. HRMS (ESI) m / z calcd for C 29 H 53 N2O 19 [M + H] + 733.3243, found 733.3249. This invention is not limited to the specific embodiments described above. Any modifications made by those skilled in the art based on the above concept without creative effort are within the scope of protection of this invention.

Claims

1. A method for preparing A, B, and Lewis blood group antigens, characterized in that, The A, B, and Lewis blood group antigens specifically refer to blood group A. tri Antigen, B tri Antigen, Le a Antigen and Le b Antigens, including the following steps: (1) Blood type A tri Preparation of antigens: A11, 4,6-benzylene protection, 3-photosensitive protecting group ( o The NBC-protected galactose receptor 5 and the all-benzyl-protected fucosylate donor 6 undergo a first glycosylation reaction to yield a disaccharide protected with a photosensitive protecting group. The photosensitive protecting group is then removed by light irradiation, generating an in-situ hydroxyl-exposed disaccharide receptor. This receptor then undergoes a second glycosylation reaction with the 2-azide-, 3,4,6-acetyl-protected trichloroacetylimine ester donor 7 to yield A. tri Trisaccharide antigen backbone 8; A12, A tri The azide group of the trisaccharide antigen backbone 8 is reduced to an amino group, followed by an acetylamino protection reaction, then the benzoyl group is removed by saponification, and then A is... tri The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 8 undergo a reductive removal reaction to obtain blood type A. tri Antigen; its synthetic route is as follows: ； (2) B tri Preparation of antigens: B21, 4,6-benzylene protection, 3-photosensitive protecting group ( o The NBC-protected galactose receptor 5 and the fully benzyl-protected fucosylate donor 6 undergo a first glycosylation reaction to yield a disaccharide protected with a photosensitive protecting group. Upon photoirradiation, the photosensitive protecting group is removed, generating an in-situ hydroxyl-exposed disaccharide receptor. This receptor then undergoes a second glycosylation reaction with the fully benzyl-protected galactosesylate donor 9 to yield B. tri Trisaccharide antigen backbone 10; B22, B tri The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 10 undergo a reductive removal reaction to yield B. tri Antigen; its synthetic route is as follows: ； (3) Le a Preparation of antigens: L31. A galactosidase donor 11 protected with a photosensitive protecting group (oNBC) and a glucose acceptor 12 protected with a trichloroacetyl group at position 2 and a 4,6-benzyl group are glycosylated to obtain a disaccharide 13. L32. The disaccharide 13 is subjected to a selective reduction ring-opening reaction to obtain a product containing a photosensitive protecting group ( o NBC) protected disaccharide receptor 14; L33, containing photosensitive protective groups ( o The NBC-protected disaccharide receptor 14 undergoes glycosylation with the all-benzyl-protected fucosinolate donor 15 to yield Le a Trisaccharide antigen backbone 16; L34. Benzoyl, acetyl, and o-nitrobenzyloxycarbonyl groups are removed through a saponification reaction, and then Le... a The benzyl and benzyloxycarbonyl groups of the trisaccharide antigen backbone 16 undergo a reductive removal reaction to yield Le. a The antigen, and its synthetic route are as follows: ； (4) Le b Preparation of antigens: L41, The photosensitive protective group obtained in step L32 ( o The NBC-protected disaccharide acceptor 14 and the fully benzyl-protected fucosinolate donor 15 undergo a first glycosylation reaction to yield a trisaccharide protected with a photosensitive protecting group. Upon photoirradiation, the photosensitive protecting group is removed, generating an in-situ hydroxyl-exposed trisaccharide acceptor. This acceptor then undergoes a second glycosylation reaction with the fully benzyl-protected fucosinotrifluorophenylacetylimine ester donor 17 to yield Le. b Tetrasaccharide antigen backbone 18; L42, benzoyl and acetyl groups are removed through a saponification reaction, and then Le... b The benzyl and benzyloxycarbonyl groups of the tetrasaccharide antigen backbone 18 undergo a reductive removal reaction to yield Le. b The antigen, and its synthetic route are as follows: 。 2. The preparation method according to claim 1, characterized in that, In steps A11, B21, and B41, the catalyst for the first glycosylation reaction is any one of Ph3PAuOTf, Ph3PAuNTf2, SPhosAuOTf, SPhosAuNTf2, NIS / TMSOTf, NIS / TBSOTf, and NIS / TfOH; the solvent for the first glycosylation reaction is dichloromethane or toluene; and molecular sieves are used to remove water in the first glycosylation reaction.

3. The preparation method according to claim 1, characterized in that, In step A11, the 4,6-benzylene protection group and the 3-position photosensitive protection group ( o The molar ratio of NBC-protected galactose acceptor 5, all-benzyl-protected fucosylate donor 6, and catalyst for the first glycosylation reaction is 1:1.2~2:0.5~1.0; the catalyst for the second glycosylation reaction is one or a combination of two or more of TMSOTf, TBSOTf, TfOH, and BF3·Et2O, and the molar ratio of galactose acceptor 5, trichloroacetylimine ester donor 7, and catalyst for the second glycosylation reaction is 1:4~6:1.5~2.0; the photoprotection reaction is carried out under a 300-400 nm ultraviolet lamp for 0.5~1 h.

4. The preparation method according to claim 1, characterized in that, In step A12, the reagent for the acetylamino protection reaction is acetyl chloride or acetic anhydride. tri The molar ratio of the reagent for the trisaccharide antigen backbone 8 to the acetylamino protection reaction is 1:15~20; the solvent for the acetylamino protection reaction is a mixed solution of dichloromethane and methanol, and the volume ratio of dichloromethane to methanol is 0.1~0.2:

1. The reaction system for reducing the azide group to an amino group comprises: zinc powder as a reducing agent, acetic acid, triphenylphosphine, 1,3-propanedithiol, and tetrahydrofuran as solvents, wherein A tri The molar ratio of the trisaccharide antigen backbone 8, zinc powder, and acetic acid is 1:45~100:25~50; The reaction reagent for the reduction and removal reaction is one or more of palladium on carbon, palladium hydroxide on carbon, a mixture of palladium on carbon and palladium hydroxide on carbon, and Raney nickel, more preferably palladium hydroxide on carbon or a combination of palladium on carbon and palladium hydroxide on carbon; the reduction and removal reaction is carried out under hydrogen conditions.

5. The preparation method according to claim 2, characterized in that, In step B21, the 4,6-benzylene protection group and the 3-photosensitive protection group ( o The molar ratio of NBC-protected galactose acceptor 5, fully benzyl-protected fucosylate donor 6, and catalyst for the first glycosylation reaction is 1:1.2~2:0.5~1.0; The 4,6-benzylene protected group at the 3-position photosensitive protecting group ( o The molar ratio of NBC-protected galactose receptor 5, galactosyl ester donor 9, and the catalyst for the second glycosylation reaction is 1:2~4:1.0~2.0; The photoprotective group removal reaction was carried out under a 300-400 nm ultraviolet lamp for 0.5-1 h.

6. The preparation method according to claim 1, characterized in that, In step L31, the catalyst for the glycosylation reaction is NIS / TfOH, and the molar ratio of the galactosidoside donor 11, glucose acceptor 12, and NIS / TfOH is 1:1.2~3:2~6:0.1~1.

0. In step L32, the reduction system for the selective reduction ring-opening reaction is any one of NaBH3CN / HCl, NaBH3CN / tetrafluoroboric acid-diethyl ether complex, NaBH3CN / TFA, NaBH3CN / BF3·Et2O, Et3SiH / HCl, Et3SiH / tetrafluoroboric acid-diethyl ether complex, Et3SiH / TFA, and Et3SiH / BF3·Et2O, more preferably NaBH3CN / tetrafluoroboric acid-diethyl ether complex; the molar ratio of the galactosinolate donor 11 protected by the photosensitive protecting group (oNBC) and sodium cyanoborohydride to the tetrafluoroboric acid-diethyl ether complex is 1:30~50:30~50; the solvent for the selective reduction ring-opening reaction is tetrahydrofuran; In step L33, the catalyst for the glycosylation reaction is NIS / TfOH, and the catalyst containing the photosensitive protecting group ( o The molar ratio of NBC-protected disaccharide receptor 14 to fully benzyl-protected fucosinolate donor 15, NIS, and TfOH is 1:1.2~2:2~6:0.1~1.

0.

7. The preparation method according to claim 1, characterized in that, In steps A12, L34, and L42, the solvent for the saponification reaction is a mixed solution of dichloromethane and methanol; the reagent for the saponification reaction is any one of sodium methoxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; A tri The molar ratio of the trisaccharide antigen backbone 8 to the reagent for the saponification reaction is 1:0.1~0.3; Le a The molar ratio of the trisaccharide antigen backbone 16 to the reagents for the saponification reaction is 1:0.3~50; the Le b The molar ratio of tetrasaccharide antigen backbone 18 to the reagent for saponification reaction is 1:0.2~50.

8. The preparation method according to claim 2, characterized in that, In step L41, the catalyst for the first glycosylation reaction is NIS / TfOH, and the photosensitive protecting group ( o The molar ratio of NBC-protected disaccharide receptor 14 to fully benzyl-protected fucosinolate donor 15, NIS, and TfOH was 1:1.2~2:2~6:0.1~1.

0. The catalyst for the second glycosylation reaction is one or a combination of two or more of TMSOTf, TBSOTf, TfOH, and BF3·Et2O; the molar ratio of the disaccharide acceptor 14, the fucose trifluorophenylacetylimine ester donor 17, and the catalyst for the second glycosylation reaction is 1:2~4:0.5~2.

0. The photosensitive protective group removal reaction was carried out under a 300-400 nm ultraviolet lamp for 1-3 hours.

9. The preparation method according to claim 1, characterized in that, In steps A12, B22, L34, and L42, the reaction reagent for the reduction and removal reaction is one or a combination of two or more of palladium on carbon, palladium hydroxide on carbon, a mixture of palladium on carbon and palladium hydroxide on carbon, and Raney nickel; the reduction and removal reaction is carried out under hydrogen conditions.

10. The preparation method according to claim 9, characterized in that, In step A12, A tri The molar ratio of the trisaccharide antigen backbone 8 to the reaction reagent for the reduction and removal reaction is 1:9~15; the solvent for the reduction and removal reaction is a mixed solution of tetrahydrofuran, water and acetic acid, and the volume ratio of tetrahydrofuran, water and acetic acid is (1.3~1.5):1:(0.05~0.06). In step B22, the B tri The molar ratio of the trisaccharide antigen backbone 10 to the reaction reagent for the reduction and removal reaction is 1:30~40, and the solvent is a mixed solution of tetrahydrofuran, water and acetic acid, with a volume ratio of (1.3~1.5):1:(0.05~0.06). In step L34, the Le a The molar ratio of the trisaccharide antigen backbone 16 to the reaction reagent for the reduction and removal reaction is 1:9~15. The solvent for the reduction and removal reaction is a mixed solution of methanol, tetrahydrofuran, water and acetic acid, and the volume ratio of methanol, tetrahydrofuran, water and acetic acid is (2~5):(1~3):1:(0.1~0.5). In step L42, the Le b The molar ratio of the tetrasaccharide antigen backbone 18 to the reaction reagent for the reduction and removal reaction is 1:50~100:50~100; the solvent for the reduction and removal reaction is a mixed solution of methanol, tetrahydrofuran, water and acetic acid, and the volume ratio of methanol, tetrahydrofuran, water and acetic acid is (2~5):(1~3):1:(0.1~0.5).

Images