TWI667252B - Alpha-selective sialyl donors and its uses for preparation of sialosides - Google Patents

Abstract

The present disclosure relates to a sialic acid donor and its use in the synthesis of gangliosides. The sialic acid donor has the structure of formula (I), Wherein R ₁ and R ₂ are respectively benzamyl, toluenesulfonyl, trimethylethenyl or ethyl hydrazino which may be optionally substituted by halogen; and R ₃ is ethenyl or -(O)CCH ₂ OH. In a preferred embodiment, in the sialic acid donor of formula (I), R is an ethenyl group. The present disclosure also provides a method for synthesizing a sialic acid. The method comprises: coupling a sialic acid donor of formula (I) to a glycosidic receptor having a primary hydroxyl group under suitable conditions with N -iodosuccinimide and trifluoromethanesulfonic acid; and isolating the A sialic acid glycoside having an alpha-glucosidic linkage. According to a preferred embodiment, the coupling is carried out in a solvent selected from the group consisting of CH ₃ CN, CH ₃ Cl and CH ₂ Cl ₂ at a temperature between -20 ° C and -60 ° C. Additionally or alternatively, the coupling can be carried out in CH ₂ Cl ₂ at a temperature of -40 °C.

Description

Avar-selective sialic acid donor and its use in the preparation of sialic acid

The present disclosure relates to the synthesis of sialoside. In particular, the present disclosure relates to a novel sialic acid donor that assists in alpha-stereoselective sialylation when synthesizing a natural sialic acid; and the novel sialic acid The use of a donor for the synthesis of sialic acid.

Sialic acid is a diverse family of carboxylated sugars with a skeleton of 9 carbon atoms, which is widely expressed on the cell surface of all animals and is usually located at the terminal position of the complex saccharide on the cell surface. It plays a functional role in different biological and pathological reactions such as cell-cell attachment and recognition, cell differentiation, message transmission, and tumor metastasis. Therefore, sialic acid glycosides and their oligomers have potential for application in the field of medicine, and synthesis of complex saccharides containing sialic acid is also extremely important in the medical field.

Natural sialic acid glycosides have α-raceomerization (α-anomer) structure. Based on the C-1 carboxyl group of the fourth-order rotational isomeric center, and lacking the stereo-control group at the C-3 position to regulate the α-stereoselective sialylation reaction, there is still a lack of high yield and efficient α-stereoselective saccharification. The sialic acid donor of the reaction. Many researchers have attempted to develop effective strategies and/or methods for alpha-sialylation, yet have not produced satisfactory results.

In view of this, there is a need in the related art for an improved strategy for stereoselective synthesis of sialic acid glycosides having an α-raceomeric structure without affecting the yield.

SUMMARY OF THE INVENTION The Summary of the Disclosure is intended to provide a basic understanding of the present disclosure. This Summary is not an extensive overview of the disclosure, and is not intended to be an

The present disclosure relates to a novel and unique sialic acid donor which, when synthesizing a natural sialic acid, can undergo an alpha-stereoselective sialylation reaction at the C-3 position, thereby allowing the sialic acid donor to be highly Alpha-stereoselective saccharification and improved yield. Accordingly, the present disclosure also provides a method of synthesizing a sialic acid using the novel sialic acid donor.

A first aspect of the present disclosure is directed to providing a sialic acid donor having the structure of formula (I), Wherein R ₁ and R ₂ are respectively benzoyl, toluenesulfonyl, pivaloyl or acetyl (acetyl) which may be optionally substituted by halogen; And R ₃ is ethenyl or -(O)CCH ₂ OH.

According to a preferred embodiment, in the sialic acid donor of formula (I), R ₁ and R ₂ are each a benzamidine group, and R ₃ is an ethenyl group.

According to another preferred embodiment, in the sialic acid donor of formula (I), R ₁ and R ₂ are each a benzamidine group, and R ₃ is -(O)CCH ₂ OH.

A second aspect of the present disclosure is directed to a method for synthesizing a sialic acid. The method comprising: (a) having N - iodosuccinimide (PEI) (N -iodosuccinimido, NIS) and trifluoromethanesulfonic acid (triflueromothanesulfonic acid, TfOH) of suitable conditions, to a sialic acid donor and having a Hydroxyglycoside receptor coupling; and (b) isolated from the sialic acid glycoside having an alpha-glycosidic linkage; wherein the sialic acid donor has the structure of formula (I) ,

Wherein R ₁ and R ₂ are respectively benzamyl, toluenesulfonyl, trimethylethenyl or ethyl hydrazino which may be optionally substituted by halogen; and R ₃ is ethenyl or -(O)CCH ₂ OH.

According to some embodiments of the present disclosure, step (a) is at a temperature between -20 ° C and -60 ° C in a group selected from the group consisting of CH ₃ CN, CH ₃ Cl and CH ₂ Cl ₂ Coupling in the solvent. Preferably, the coupling is carried out in CH ₂ Cl ₂ at a temperature of -40 °C.

According to an embodiment of the present disclosure which is not essential, step (a) of the method of the invention is carried out by a powder molecular sieve.

The basic spirit and other objects of the present invention, as well as the technical means and implementations of the present invention, will be readily apparent to those skilled in the art of the invention.

The description of the embodiments of the present invention is intended to be illustrative and not restrictive. The features of various specific embodiments, as well as the method steps and sequences thereof, are constructed and manipulated in the embodiments. However, other specific embodiments may be utilized to achieve the same or equivalent function and sequence of steps.

Definition

Certain terms used in the present disclosure are set forth below. The scientific and technical terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention pertains, unless otherwise defined herein.

In the present disclosure, the term "Pic" refers to picolinyl or 2-pyridylmethyl; and the term "Pico" refers to picoloyl or 2 -2-pyridine carbonyl.

The term "halo" or "halogen" refers to fluorine (fluorine, fluoro, -F), chlorine (chlorine, chloro, -Cl), bromine (bromine, bromo, -Br) or iodine (iodine, iodo, -I). ).

Unless otherwise indicated, each benzamidine, toluenesulfonyl, trimethylethenyl or ethenyl group is optionally substituted, that is, it may be unsubstituted ( An "unsubstituted benzhydryl group", or substituted with one or more substituents (a "substituted ethylidene"). When used to describe a chemical structure or chemical domain, the term "substituted" refers to a derivative of the structure or domain in which one or more halogens or hydroxyl groups are substituted for a hydrogen atom.

If the compound has one or more palm centers and the name does not explicitly indicate the stereochemistry of the centers, the name includes the pure stereoisomers and mixtures thereof. In addition, the atoms of the unsaturated valence in the scheme should be considered to be connected to a sufficient number of hydrogen atoms to satisfy their valence.

Although numerical ranges and parameters are used to define a wide range of the invention, the numerical values are approximated as much as possible. Relevant values in the example. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "about" means that the actual value falls within the acceptable standard error of the average, depending on the considerations of those of ordinary skill in the art to which the invention pertains. Except for the experimental examples, or unless otherwise explicitly stated, all ranges, quantities, values, and percentages used herein are understood (eg, to describe the amount of material used, the length of time, the temperature, the operating conditions, the quantity ratio, and the like. Are all modified by "about". Therefore, unless otherwise indicated to the contrary, the numerical parameters disclosed in the specification and the appended claims are intended to be At a minimum, these numerical parameters should be understood as the number of significant digits indicated and the values obtained by applying the general carry method. Ranges of values are expressed herein as being from one endpoint to another or between two endpoints; unless otherwise stated, the numerical ranges recited herein are inclusive.

Unless otherwise indicated, the singular noun used in this specification encompasses the plural of the noun, and the plural noun used also encompasses the singular of the noun.

2. Description of preferred embodiments

The present disclosure is based, at least in part, on the inventors' discovery of a novel sialic acid donor that allows a glycosyl acceptor to form an alpha-orientation. Unexpectedly, in the appropriate solvent (for example, CH ₂ Cl _{2 ,} etc.) having N -iodosuccinimide and catalytic trifluoromethane at a temperature of -20 ° C to -60 ° C, the novel sialic acid The donor can undergo a saccharification reaction with a high degree of a-stereoselectivity (98-100%). The saccharification reaction can be carried out in a short time (for example, 0.5 hours) to prepare a product mainly having an α-raceotropic structure. Therefore, the novel sialic acid donor of the present invention can be used to stereoselectively synthesize a natural sialic acid glycoside having an α-raceotropic structure including, but not limited to, ganglioside Hp-s1.

To confirm that a preferred glycosidic receptor can form an alpha-directed sialic acid donor, the present disclosure synthesizes several potential sialic acid donors and reacts with glycosyl acceptors, respectively. Accordingly, a first aspect of the present disclosure is directed to a novel sialic acid donor having the structure of formula (I), Wherein R ₁ and R ₂ are each a benzamyl group, a toluenesulfonyl group, a trimethylethyl fluorenyl group or an ethyl fluorenyl group which may be optionally substituted by a halogen; and R ₃ is an ethyl fluorenyl group or an -(O)CCH group; ₂ OH.

According to an embodiment of the present disclosure, the sialic acid donor of formula (I) may be any of the following:

In a preferred embodiment, R ₁ and R _{2 of} formula (I) are each a benzamidine group, and R ₃ is an ethylidene group, which is a sialic acid donor (ie, compound 1d), After the reaction of the monosaccharide-based receptor, only the α-raceomer is produced (i.e., the α-stereoselectivity is 100%).

In another preferred embodiment, R ₁ and R _{2 of} formula (I) are each a benzamidine group, and R ₃ is -(O)CCH ₂ OH (ie, compound 1h).

A second aspect of the present disclosure is directed to a method for synthesizing a sialic acid. The method comprises: (a) coupling a monosialic acid donor to a glycosidic receptor having a primary hydroxyl group under suitable conditions with N -iodosuccinimide (NIS) and trifluoromethanesulfonic acid (TfOH) And (b) detaching the sialic acid having an α-glycosidic bond; wherein the sialic acid donor has the structure of the formula (I), Wherein R ₁ and R ₂ are each a benzamyl group, a toluenesulfonyl group, a trimethylethyl fluorenyl group or an ethyl fluorenyl group which may be optionally substituted by a halogen; and R ₃ is an ethyl fluorenyl group or an -(O)CCH group; ₂ OH.

According to some embodiments of the present disclosure, in step (a) of the method of the invention, at a temperature between -20 ° C and -60 ° C, a choice of CH ₃ CN, CH ₃ Cl and CH ₂ Cl Coupling is carried out in the solvent of the group consisting of _two .

In one embodiment of the present disclosure, step (a) is coupled at a temperature of -20 ° C in CH ₂ Cl ₂ comprising NIS and TfOH. The reaction can be completed in 0.5 hours with moderate α-stereoselectivity, wherein the yield of the disaccharide α-raceomer is about 5 (about 24%) of the yield of the β-helical isomer. Times.

In another embodiment of the present disclosure, step (a) is coupled at a temperature of -40 ° C in CH ₂ Cl ₂ comprising NIS and TfOH. The reaction can be completed in 2 hours with excellent alpha-stereoselectivity, wherein only alpha-rotation isomers are produced with a yield of about 70%.

In another embodiment of the present disclosure, step (a) is coupled at a temperature of -60 ° C in CH ₂ Cl ₂ comprising NIS and TfOH. The reaction can be completed in 5 hours with excellent alpha-stereoselectivity, wherein only alpha-rotation isomers are produced with a yield of about 69%.

In still another embodiment of the present disclosure, step (a) is coupled at a temperature of -40 ° C in a CH ₃ CN comprising NIS and TfOH. The reaction can be completed in 0.5 hours with excellent alpha-stereoselectivity, wherein only alpha-rotation isomers are produced with a yield of about 56%.

In a further embodiment of the present disclosure, step (a) is coupled at a temperature of -40 ° C in CHCl ₃ comprising NIS and TfOH. The reaction can be completed in 0.5 hours with excellent alpha-stereoselectivity, wherein only alpha-raceomers are produced, but the yield is only about 20%.

Optionally or additionally, a powdered molecular sieve (e.g., MS-3A) may be added to carry out the coupling reaction of step (a) of the present invention.

Preferably, the disaccharide prepared in the step (a) has an α-raceomerization structure, and in step (b), the disaccharide can be isolated from any suitable method (for example, column chromatography). .

In accordance with certain embodiments of the present disclosure, in order to identify glycosidic receptors that are most suitable for coupling to a sialic acid donor of the present disclosure, the present disclosure synthesizes several potential glycosyl acceptors, and under appropriate conditions, respectively Reaction with a sialic acid donor of the present disclosure; for example, CH ₂ Cl ₂ containing NIS and TfOH at -40 ° C, may optionally be added to MS-3A. The results indicate that in order to increase α-stereoselectivity, the coupling between the sialic acid donor and the glycosyl acceptor preferably occurs in the primary hydroxyl group (or primary alcohol); therefore, the structure of the glycosyl acceptor preferably comprises a primary alcohol. . In certain embodiments, a sugar alcohol having a secondary hydroxyl group (eg, compound 5e) is utilized as a glycosyl acceptor, however, coupling does not occur between the sialic acid donor and the sugar alcohol of the present disclosure. reaction.

Another aspect of the present disclosure is directed to a method for synthesizing a natural ganglioside comprising an alpha-raceomeric structure. The method uses a sialic acid donor of formula (I) as a starting material to form a glycosidic receptor to form an alpha-orientation. In general, depending on the ganglioside to be synthesized, the sialic acid donor of formula (I) can be reacted under the preferred conditions identified in the present disclosure (ie, CH ₂ Cl ₂ containing NIS and TfOH, reaction) The temperature is -40 ° C, and optionally MS-3A) can be added to react with a glycosidic receptor having a primary hydroxyl group to prepare a disaccharide having an α-glycosidic bond, which can be prepared by any conventional synthetic procedure. Specific gangliosides.

According to a preferred embodiment of the present disclosure, the sialic acid donor of formula (I) is used as a starting material for the preparation of Hp-s1. Preferably, the sialic acid donor of formula (I) is first reacted with S-thiazolyl receptor in CH ₂ Cl ₂ containing NIS, TfOH and MS-3A at a temperature of -40 °C. . The reaction produces a disaccharide having only an α-raceomeric structure, which is a deprotecting disaccharide (ie, a methyl oxime from which the disaccharide is removed), followed by further phytoceramide with acetaminophen (phytoceramide). The reaction is carried out to obtain a protected group of Hp-s1. The protective group of Hp-s1 is then subjected to a series of deprotection reactions including deisopropylidenenation, debenzylation, deacetylation, and saponification. According to the preparation of specific ganglioside Hp-s1.

Several experimental examples are presented below to illustrate certain aspects of the invention It is to be understood that the present invention is not limited by the scope of the invention. It is believed that the skilled artisan, after reading the description set forth herein, may fully utilize and practice the invention without undue interpretation. All publications cited herein are hereby incorporated by reference in their entirety.

Example

Materials and methods

Cell line and cell culture

A549 cells were obtained from the American Type Culture Collection (ATCC; Manassas, VA, USA). A549 cells were cultured to contain 1.5 grams of sodium bicarbonate per milliliter, 10% fetal bovine serum (FBS), 1.0% antibiotic (anti-mold agent), L-glutamic acid (2.0×10 ^-3 M) and 1.0% non-essential amino acid in DMEM (Dulbecco's minimal essential medium) cell culture medium. Cell number and survival were analyzed using the trypan blue exclusion method and the Alamar Blue assay, respectively.

Example 1 Screening for sialic acid donors and evaluating the optimal conditions for sialic acid donor saccharification

To confirm the suitability of a glycosidic receptor to form an alpha-directed sialic acid donor, several different sialic acid donors were synthesized in this experiment (see Example 1.1 for details) and in a suitable environment, with a glucosyl group. The glucosyl acceptor is coupled, followed by isolation and analysis of the alpha-stereoselectivity of the product (see Example 1.2 for details). Confirm that compounds 1d and 1h are of higher yield The preferred sialic acid donor.

1.1 Preparation of sialic acid donor

1.1.1 Preparation of sialic acid donor 1c

(phenyl 5-acetamido-3,5-dideoxy-8,9-O-isopropylidene-2-thio-D-propyltriyl-D-galacto-2-pyranone Methyl(phenyl 5-acetamido-3,5-dideoxy-8,9-O-isopropylidene-2-thio-D-glycero-D-galacto-2-nonulopyranosid) onate (s2)

2,2-Dimethoxypropane (4.4 ml, 36.15 mmol) and CSA (4.454 g, 19.28 mmol) were added to the anhydrous compound containing compound s1 (10.006 g, 24.10 mmol) at 0 °C. In acetonitrile (240 ml). The mixture was allowed to warm to room temperature and stirring was continued at this temperature for 2 hours. After Et ₃ N (5.0 mL) was added to the reaction mixture, concentrated in vacuo. Using MeOH and CH ₂ Cl ₂ (1:15, by volume) as a solvent, the yellow slurry product was purified by flash column chromatography on silica gel to afford 10.109 g of white solid s2 , yield 92%: R _f = 0.25 (MeOH: CH ₂ Cl ₂ = 1:15 (volume ratio)); FT-IR (neat) v _max 3299, 3083, 2993, 2953, 1737, 1660, 1557, 1439, 1377, 1263, 1202, 1135, 1065, 901, 756, 696, 666, 609 cm ^-1 ; ¹ H NMR (400 MHz, CD ₃ OD) δ □ 7.55-7.53 (m, 2H), 7.39-7.36 (m, 1H), 7.32-7.28 (m, 2H), 4.34 ( Dd, J = 10.5, 0.9 Hz, 1H), 4.16-4.08 (m, 2H), 3.98-3.82 (m, 3H), 3.56 (dd, J = 7.5, 0.9 Hz, 1H), 3.51 (s, 3H) , 2.69 (dd, J = 13.6, 4.7 Hz, 1H), 2.02 (s, 3H), 1.95 (dd, J = 13.6, 11.8 Hz, 1H), 1.39 (s, 3H), 1.38 (s, 3H), 1.30(s,3H), 1.21(s,3H); ¹³ C NMR (100MHz, CD ₃ OD) δ 173.4(C), 169.2(C), 136.0(CH), 129.8(C),129.3(CH), 128.5(CH),108.8(C),90.0(C),74.7(CH),72.6(CH),70.0(CH),66.6(CH ₂ ),66.4(CH),52.7(CH),51.8(CH ₃ ), 48.5 (CH ₃ ), 40.9 (CH ₂ ), 25.9 (CH ₃ ), 24.7 (CH ₃ ), 21.6 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₂₁ H ₂₉ NO ₈ SNa 478.1506, Found 478.1499.

(Phenyl 5-acetamido-3,5-dideoxy-8,9-O-isopropylidene-4,7-di-O-methylindole-2-thio-D-propane Methyl(phenyl 5-acetamido-3,5-dideoxy-8,9 -O-isopropylidene-4,7-di-O-picoloyl-2-thio-D-glycero-D-galacto-2-nonulopyranosid)onate)(s3)

2-picolinic acid (6.765 grams, 55.00 millimoles), DMAP (0.268 grams, 2.20 millimoles) and DCC (10 milliliters, 66.00 millimoles) were added to the compound containing s2 (10.003 grams, 22.00 at 0 °C). Millions of anhydrous dichloroethane (73 ml). The mixture was allowed to warm to room temperature and stirring was continued at this temperature for 2 hours. The mixture was filtered through a short pad of celite and concentrated in vacuo. Acetone and ethyl acetate (1:1, by volume) were used as the extract, and the observed black solid was purified by flash column chromatography to give 13.919 g of white solid s3 , yield 92%: R _f = 0.23 (Acetone: ethyl acetate = 1:1 (volume ratio)); FT-IR (neat) v _max 3330, 2988, 1739, 1675, 1581, 1543, 1438, 1373, 1307, 1245, 1213, 1131, 1089, ^{1053,994,751,701cm -1; 1 H NMR (400MHz} , CDCl 3) δ8.77 (d, J = 4.0Hz, 1H), 8.73 (d, J = 4.0Hz, 1H), 8.10 (d, J = 7.8Hz , 1H), 8.03 (d, J = 7.8 Hz, 1H), 7.84 (td, J = 7.8, 1.7 Hz, 1H), 7.79 (td, J = 7.8, 1.7 Hz, 1H), 7.59-7.57 (m, 2H), 7.49 (m, 5H), 6.08 (ddd, J = 11.6, 10.8, 4.9 Hz, 1H), 5.94-5.88 (m, 1H), 5.81-5.80 (m, 1H), 5.11 (dd, J = 10.5, 1.8 Hz, 1H), 4.14 - 4.06 (m, 2H), 3.98-3.91 (m, 1H), 3.73 (dd, J = 7.2, 5.9 Hz, 1H), 3.65 (s, 3H), 2.93 (dd , J=13.7, 4.9 Hz, 1H), 2.26 (dd, J=13.7, 11.6 Hz, 1H), 1.90 (s, 3H), 1.29 (s, 3H), 1.21 (s, 3H); ¹³ C NMR ( 75 MHz, CDCl ₃ ) δ 170.7 (C), 170.6 (C), 168.3 (C), 164.4 (C), 164.3 (C), 150.0 (CH), 149.9 (CH), 147.6 (C), 147.2 (C) ), 137.2 (CH), 137.1 (CH), 136.9 (CH), 136.3 (CH), 129.8 (CH), 129.3 (CH), 128.9 (CH), 127.2 (CH), 127.0 (CH), 125.6 (CH) ), 125.5 (CH), 108.5 (C), 108.4 (C), 88.8 (C), 87 .7(C),75.4(CH),71.7(CH),71.0(CH),70.7(CH),70.2(CH),65.8(CH ₂ ),65.5(CH ₂ ),52.9(CH ₃ ),52.5 (CH ₃ ), 50.6 (CH), 38.1 (CH ₂ ), 26.3 (CH ₃ ), 26.2 (CH ₃ ), 25.4 (CH ₃ ), 25.1 (CH ₃ ), 23.3 (CH ₃ ); HRMS-ESI [ M+Na] ⁺ Calcd for C ₃₃ H ₃₅ N ₃ O ₁₁ SNa 688.1935, Found 688.1918.

(Phenyl 5-acetamido-3,5-dideoxy-4,9-di-O-methylindole-2-thio-D-propyltriyl-D-semi-milk-non-2- Methyl(phenyl 5-acetamido-3,5-dideoxy-4,9-di-O-picoloyl-2-thio-D-glycero-D-galacto-non-2-ulopyranoside) onate S4)

The isopropylidene acetal s3 (8.000 g, 12.79 mmol) was dissolved in 80% AcOH solution (120 ml) at 0 ° C, and the mixture was continuously stirred at 70 ° C for 4 hours. The reaction mixture was co-evaporated with toluene to give a white solid residue. After 6.647 g of s4 was recrystallized (MeOH/CH ₂ Cl ₂ ) to give a white solid compound (yield 86%: _Rf =0.28 (MeOH: CH ₂ Cl ₂ = 1:9 (volume ratio)); IR (neat) v _max 3311, 3064, 3009, 2954, 1732, 1659, 1555, 1439, 1375, 1309, 1246, 1136, 1089, 1047, 998, 752, 701 cm ^-1 ; ¹ H NMR (400 MHz, CD ₃ OD) δ 8.69-8.68 (m, 2H), 8.22 (dt, J = 7.9, 0.9 Hz, 1H), 8.09 (dt, J = 7.9, 0.9 Hz, 1H), 8.00 (td, J = 7.8, 1.6 Hz, 1H) , 7.91 (td, J = 7.8, 1.6 Hz, 1H), 7.65-7.54 (m, 4H), 7.36-7.31 (m, 3H), 5.68 (ddd, J = 11.6, 8.4, 4.8 Hz, 1H), 4.75 -4.69 (m, 2H), 4.43-4.36 (m, 2H), 4.16 (ddd, J = 9.0, 6.6, 2.3 Hz, 1H), 3.7 (dd, J = 9.0, 0.8 Hz, 1H), 3.50 (s , 3H), 2.94 (dd, J = 13.5, 4.8 Hz, 1H), 2.28 (dd, J = 13.5, 11.6 Hz, 1H), 1.99 (s, 3H); ¹³ C NMR (75 MHz, CD ₃ OD) δ 173 .8(C),173.5(C),172.9(C),169.2(C),168.3(C),164.8(C),164.7(C),164.6(C),150.2(CH),149.7(CH) , 149.2 (CH), 147.8 (C), 147.6 (C), 146.9 (C), 137.7 (CH), 137.5 (CH), 137.3 (CH), 136.9 (CH), 136.1 (CH), 129.5 (CH) , 129.5 (CH), 128.9 (CH), 128.8 (CH), 127.5 (CH), 127.3 (CH), 125.6 (CH), 125.3 (CH), 89.6 (C), 72.5 (CH), 70.5 (CH) ,69.4(CH),68.7(CH ₂ ),68.3(CH),52.5(CH ₃ ),50.8(CH ₃ ),38.0(CH ₂ ),23.0(CH ₃ ),22 .9(CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₀ H ₃₁ N ₃ O ₁₀ SNa 648.1622, Found 648.1629.

(phenyl 5-acetamido-7,8-di-O-benzhydryl-3,5-dideoxy-4,9-di-O-methylindole-2-thio-D- Methyl(phenyl 5-acetamido-7,8-di-O-benzoyl-3,5-dideoxy-4,9-di-O- picoloyl-2-thio-D-glycero-D-galacto-non-2-ulopyranosi De)onate)(1c)

Benzamidine chloride (0.08 ml, 0.70 mmol) was added to anhydrous pyridine (1.6 mL) containing compound s4 (0.200 g, 0.32 mmol). The mixture was continuously stirred at this temperature for 5 hours. The reaction mixture was placed on ice, extracted with ethyl acetate, and using ₂ CO ₃ solution and the product was washed with saturated brine, K, to then dried over MgSO ₄ and concentrated in vacuo process. With ethyl acetate and n-hexane (2.5: 1, volume ratio) as eluent, to flash column chromatography on silica gel to give a white solid residue, to produce a compound 1c as a white solid, yield 0.255 g of 96%: R _f =0.28 (ethyl acetate: n-hexane = 3:1 (volume ratio)); FT-IR (neat) v _max 3324, 3066, 2919, 2852, 1731, 1674, 1546, 1443, 1369, 1266, 1097 , 1035, 894, 754, 712, 610cm ^-1 ; ¹ H NMR (400MHz, CDCl ₃ ) δ 8.92 (d, J = 4.1 Hz, 1H), 8.77 (d, J = 4.1 Hz, 1H), 8.07-7.97 (m, 6H) , 7.85-7.78 (m, 2H), 7.60 (t, J = 7.4 Hz, 1H), 7.54-7.44 (m, 5H), 7.40-7.36 (m, 4H), 7.14-7.09 (m, 3H), 6.97 (d, J = 9.6 Hz, 1H), 6.06 (dd, J = 4.2, 1.8 Hz, 1H), 5, 91 (ddd, J = 13.5, 10.1, 4.9 Hz, 1H), 5.71 (ddd, J = 6.5) , 4.8, 1.8 Hz, 1H), 5.12 (dd, J = 10.1, 4.2 Hz, 1H), 5.07 (dd, J = 11.8, 4.8 Hz, 1H), 4.58 (dd, J = 11.8, 7.1 Hz, 1H) , 4.38 (q, J = 10.1 Hz, 1H), 3.54 (s, 3H), 2.84 (dd, J = 13.5, 4.9 Hz, 1H), 2.35 (dd, J = 13.5, 11.8 Hz, 1H), 1.85 ( s,3H); ¹³ C NMR (100MHz, CDCl ₃ ) δ170.4 (C), 168.0 (C), 165.8 (C), 164.4 (C), 164.4 (C), 163.8 (C), 150.0 (CH) , 149.9 (CH), 147.3 (C), 147.0 (C), 137.3 (CH), 136.9 (CH), 136.1 (CH), 133.1 (CH), 133.0 (CH), 129.8 (CH), 129.7 (CH) , 129.6(C), 129.4(CH), 129 .3(C), 129.0(C), 128.8(CH), 128.3(CH), 128.3(CH), 127.1(CH), 126.8(CH), 125.7(CH), 125.0(CH), 88.9(C) , 73.0 (CH), 72.7 (CH), 71.0 (CH), 70.8 (CH), 63.8 (CH ₂ ), 52.3 (CH ₃ ), 49.5 (CH), 37.5 (CH ₂ ), 23.0 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₄ H ₃₉ N ₃ O ₁₂ SNa 856.2147, Found 856.2146.

1.1.2 Preparation of sialic acid donors 1a and 1e

(phenyl 5-acetamido-4,8,9-tri-O-benzhydryl-3,5-dideoxy-2-thio-D-propyltriyl-D-semi-milk-non- Methyl(phenyl 5-acetamido-4,8,9-tri-O-benzoyl-3,5-dideoxy-2-thio-D-glycero-D-galacto-non-2-ulopyranoside ) onate(s5); and (phenyl 5-acetamido-4,7,8,9-tetra-O-benzhydryl-3,5-dideoxy-2-thio-D-propane Methyl(phenyl 5-acetamido-4,7,8,9-tetra-O-benzoyl-3,5-dideoxy-2-thio-D-glycero -D-galacto-non-2-ulopyranoside)onate)(1e)

At 0 ° C, benzoic anhydride (1.085 g, 4.80 mmol) was added to contain the compound s1 (0.503 g, 1.20 mmol), Im (0.410 g, 6.02 mmol), DMAP (0.073 g, 0.60 m) Mohr) in anhydrous dichloroethane (6.0 ml). The mixture was heated to 60 ° C and stirring was continued at this temperature for 11 hours. Ice bath and the reaction mixture was added 6N HCl, extracted with ethyl acetate, after which ₂ CO ₃ solution and the product was washed with saturated brine, K, dried over MgSO ₄ and concentrated in vacuo. Ethyl acetate and n-hexane (1:2, by volume) were used as a solvent, and the obtained white solid residue was purified by flash column chromatography to obtain 0.368 g of s5 white solid compound, yield 42%. And 0.431 g of a white solid compound 1e , yield 43%: s5 : R _f = 0.38 (ethyl acetate: n-hexane = 1:1 (volume ratio)); FT-IR (neat) v _max 3355, 3066, 2954, 1721, 1663, 1602, 1548, 1448, 1373, 1269, 1172, 1112, 1070, 1027, 755, 712 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.11-8.08 (m, 2H), 8.02-8.00 ( m, 2H), 7.92-7.89 (m, 2H), 7.62-7.37 (m, 11H), 7.20-7.16 (m, 2H), 7.06-7.02 (m, 1H), 6.41 (d, J = 8.0 Hz, 1H), 5.76 (ddd, J = 11.8, 10.3, 4.8 Hz, 1H), 5.48-5.45 (m, 1H), 4.95 (dd, J = 12.2, 2.2 Hz, 1H), 4.92 (d, J = 4.1 Hz) , 1H), 4.66 (dd, J = 12.2, 8.2 Hz, 1H), 4.48 (dd, J = 10.3, 1.4 Hz, 1H), 4.24 - 4.17 (m, 1H), 4.10 (bs, 1H), 3.55 ( s, 3H), 2.87 (dd, J = 13.8, 4.8 Hz, 1H), 2.41 (dd, J = 13.8, 11.8 Hz, 1H), 1.96 (s, 3H); ¹³ C NMR (75 MHz, CDCl ₃ ) δ 173.2(C), 168.6(C), 167.1(C), 166.4(C), 165.9(C), 136.1(CH), 133.8(CH), 133.2(CH), 132.8(CH), 130.3(CH), 130.0 (CH), 129.8 (CH), 129.7 (CH), 129.6 (CH), 129.0 (CH), 128.9 (CH), 128.6 (CH), 128.6 ( CH), 128.4 (CH), 128.3 (CH), 89.3 (C), 74.8 (CH), 74.4 (CH), 69.9 (CH), 69.2 (CH), 64.0 (CH ₂ ), 52.6 (CH ₃ ), 51.8(CH),37.8(CH ₂ ), 23.1(CH ₃ ); HRMS-ESI[M+Na] ⁺ Calcd for C ₃₉ H ₃₇ NO ₁₁ SNa 750.1980, Found 750.1969; 1e :R _f =0.50 (ethyl acetate : n-hexane = 1:1 (volume ratio); FT-IR (neat) v _max 3372, 3066, 1724, 1601, 1536, 1449, 1369, 1265, 1175, 1105, 1070, 1026, 892, 755, 712 cm ^-1 ; _{^{1 H NMR (400MHz, CDCl 3}} ) δ 8.12-7.93 (m, 9H), 7.65-7.31 (m, 15H), 7.24-7.22 (m, 1H), 7.11-7.07 (m, 1H), 6.03-6.01 ( m, 1H), 5.86-5.86 (m, 1H), 5.76-5.69 (m, 2H), 5.56-5.53 (m, 2H), 5.29-5.22 (m, 1H), 5.03-4.94 (m, 3H), 4.68-4.64 (m, 1H), 4.52 (dd, J = 12.2, 8.8 Hz, 1H), 4.37 (q, J = 10.5 Hz, 1H), 4.28 (d, J = 10.5 Hz, 1H), 4.14 (q) , J = 9.9 Hz, 1H), 3.65 (s, 3H), 3.42 (s, 3H), 3.06 (dd, J = 12.8, 4.7 Hz, 1H), 2.95 (dd, J = 13.8, 4.7 Hz, 1H) , 2.32 (dd, J = 13.8, 11.8 Hz, 1H), 2.12 (dd, J = 12.8, 11.8 Hz, 1H), 1.81 (s, 3H), 1.79 (s, 3H); ¹³ C NMR (75 MHz, CDCl) ₃ ) δ170.6(C), 170.6(C), 168.8(C), 168.6(C), 166.9(C), 166.6(C), 166.5(C), 166.3(C),165.9(C),165.9 (C), 165.5(C), 136.9(CH), 136.2(CH), 133.5(CH), 133.5(CH), 133.4(CH), 133.4(CH), 133.3(CH), 133.1(CH) , 133.0 (CH), 130.1 (CH), 130.0 (CH), 129.9 (CH), 129.8 (CH), 129.8 (CH), 129.7 (CH), 129.7 (CH), 129.6 (CH), 129.3 (CH) , 129.2 (CH), 129.0 (CH), 128.8 (CH), 128.6 (CH), 128.5 (CH), 128.4 (CH), 128.3 (CH), 89.2 (C), 88.0 (C), 75.6 (CH) , 74.2 (CH), 73.5 (CH), 71.9 (CH), 70.8 (CH), 70.6 (CH), 70.4 (CH), 69.3 (CH), 63.6 (CH ₂ ), 63.2 (CH ₂ ), 52.8 ( CH ₃ ), 52.7 (CH ₃ ), 49.6 (CH), 38.3 (CH ₂ ), 38.0 (CH ₂ ), 23.1 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₆ H ₄₁ NO ₁₂ SNa 854.2242, Found 854.2253.

(Phenyl 5-acetamido-4,8,9-tri-O-benzhydryl-3,5-dideoxy-7-O-methylindole-2-thio-D-propane Methyl(phenyl 5-acetamido-4,8,9-tri-O-benzoyl-3,5-dideoxy-7-O-picoloyl-2- thio-D-glycero-D-galacto-non-2-ulopyranoside) onate)(1a)

2-picolinic acid (0.076 g, 0.62 mmol), DMAP (0.005 g, 0.04 mmol) and DCC (0.130 g, 0.82 mmol) were added to the compound containing s5 (0.305 g, 0.41) at 0 °C. Millihydrate in anhydrous CH ₂ Cl ₂ (2.0 mL). The mixture was allowed to warm to room temperature and stirring was continued at this temperature for 1.5 hours. The mixture was filtered through a short pad of celite and concentrated in vacuo. Ethyl acetate and n-hexane (1:1, by volume) were used as a solvent, and the observed black solid was purified by flash column chromatography to give 0.346 g of a white solid 1a , yield 99%: R _f =0.13 (ethyl acetate: n-hexane = 1:1 (volume ratio)); FT-IR (neat) v _max 3371, 3064, 2931, 2853, 1724, 1548, 1445, 1367, 1273, 1111, 1027, 892, 752, 712 ^{cm -1; 1 H NMR (400MHz} , CDCl 3) δ 8.81-8.79 (m, 1H), 8.79-8.77 (m, 1H), 8.19-8.16 (m, 1H), 8.16-8.13 (m, 1H), 8.03-7.82 (m, 8H), 7.63-7.61 (m, 2H), 7.55-7.44 (m, 7H), 7.41-7.35 (m, 7H), 7.27-7.24 (m, 4H), 7.14-7.10 (m , 1H), 6.06 (t, J = 2.2 Hz, 1H), 5.94-5.88 (m, 2H), 5.78-5.71 (m, 1H), 5.70 (d, J = 9.9 Hz, 1H), 5.61 (dt, J=8.4, 2.2 Hz, 1H), 5.53 (d, J=9.5 Hz, 1H), 5.32-5.25 (m, 1H), 5.07 (dd, J = 10.9, 2.9 Hz, 1H), 5.01 (dd, J =12.2, 2.2 Hz, 1H), 4.95 (dd, J = 12.2, 2.2 Hz, 1H), 4.68 (dd, J = 12.3, 5.8 Hz, 1H), 4.54 (dd, J = 12.3, 8.6 Hz, 1H) , 4.39 (q, J = 10.2 Hz, 1H), 4.34 (dd, J = 10.2, 2.2 Hz, 1H), 4.14 (q, J = 10.2 Hz, 1H), 3.62 (s, 3H), 3.67 (s, 3H), 3.09 (dd, J = 12.8, 4.7 Hz, 1H), 2.95 (dd, J = 13.8, 4.7 Hz, 1H), 2.34 (dd, J = 13.8, 11.5 Hz, 1H), 2.13 (dd, J =12.8, 11.5 Hz, 1H), 1.80 (s, 3H), 1.78 (s, 3H); ¹³ C NMR (75 MHz, CDCl) ₃ ) δ170.5(C),68.6(C),168.4(C),166.6(C),166.3(C),166.2(C),166.2(C),165.8(C),165.6(C),163.9 (C), 163.9(C), 150.0(CH), 147.4(C), 147.3(C), 137.1(CH), 136.7(CH), 136.2(CH), 133.4(CH), 133.3(CH), 133.0 (CH), 132.9 (CH), 129.8 (CH), 129.7 (CH), 129.6 (CH), 129.5 (CH), 129.2 (CH), 129.1 (CH), 128.9 (CH), 128.8 (CH), 128.7 (CH), 128.5 (CH), 128.4 (CH), 128.3 (CH), 128.2 (CH), 127.1 (CH), 125.5 (CH), 89.1 (C), 88.1 (C), 75.3 (CH), 73.7 (CH), 73.3 (CH), 71.4 (CH), 70.2 (CH), (CH), 63.5 (CH ₂ ), 63.0 (CH ₂ ), 52.7 (CH ₃ ), 52.7 (CH ₃ ), 49.8 (CH) ), 48.9 (CH), 38, 4 (CH ₂ ), 38.0 (CH ₂ ), 33.8 (CH ₂ ), 23.0 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₅ H ₄₀ N ₂ O ₁₂ SNa 855.2194, Found 855.2194.

1.1.3 Preparation of sialic acid donors 1d, 1f and 1g

(phenyl 5-acetamido-4,9-di-O-benzhydryl-3,5-dideoxy-2-thio-D-propyltriyl-D-semi-milk-non-2- Methyl(phenyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-2-thio-D-glycero-D-galacto-non-2-ulopyranoside) onate S6)

At 0 ° C, benzoic anhydride (10.848 grams, 48.12 millimoles) was added to contain the compound s1 (5.030 grams, 12.02 millimoles), Im (4.096 grams, 60.21 millimoles) and DMAP (0.732 grams, 0.60 milliliters). Mohr) in anhydrous dichloroethane (120 ml). The mixture was heated to 40 ° C and stirring was continued at this temperature for 5 hours. The reaction mixture was added ice bath and 6N HCl, and extracted in ethyl acetate, using ₂ CO ₃ solution and the product was washed with saturated brine, K, to then dried over MgSO ₄ and concentrated in vacuo process. Ethyl acetate and n-hexane (1:1, by volume) were used as a solvent, and the obtained white solid residue was purified by flash column chromatography to give 5.263 g of white solid compound s6 , yield 70%, and 1.147 g of white solid compound s5 , yield 13%: R _f = 0.13 (ethyl acetate: n-hexane = 1:1 (volume ratio)); FT-IR (neat) v _max 3349, 3065, 2953, 1720, 1660 , 1603, 1551, 1446, 1375, 1272, 1116, 1070, 1027, 754, 713 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.09-8.00 (m, 4H), 7.61 ^- 7.53 (m, 3H) , 7.50-7.39 (m, 4H), 7.32-7.28 (m, 4H), 6.42 (d, J = 8.2 Hz, 1H), 6.29 (d, J = 8.2 Hz, 1H), 5.76-5.69 (m, 1H) ), 5.27-5.20 (m, 1H), 4.74 (dd, J = 11.4, 2.4 Hz, 1H), 4.63 (dd, J = 11.4, 2.4 Hz, 1H), 4.57 (d, J = 7.2 Hz, 1H) , 4.53-4.52 (m, 1H), 4.50 (dd, J = 6.4, 5.6 Hz, 1H), 4.28-4.20 (m, 2H), 4.18-4.13 (m, 2H), 3.72 (dd, J = 8.7, 0.8 Hz, 1H), 3.61 (d, J = 8.7 Hz, 1H), 3.53 (s, 3H), 3.51 (s, 3H), 3.00 (dd, J = 12.9, 4.8 Hz, 1H), 2.87 (dd, J=13.7, 4.8 Hz, 1H), 2.36 (dd, J=13.7, 11.8 Hz, 1H), 1.95 (s, 3H), 1.92 (s, 3H); ¹³ C NMR (75 MHz, CDCl ₃ ) δ 173.2 (C), 172.8(C), 169.5(C), 168.4(C), 167.2(C), 167.1(C), 166.9(C), 137.0(CH), 135.7(CH), 133.8(CH), 133.1 (CH), 13 0.1(CH),129.9(CH),129.7(CH),129.6(CH),129.6(CH),129.5(CH),129.0(CH),128.9(CH),128.8(CH),128.7(CH), 128.6 (CH), 128.4 (CH), 128.3 (CH), 89.4 (C), 85.8 (C), 73.0 (CH), 69.5 (CH), 69.3 (CH), 69.2 (CH), 67.5 (CH ₂ ) , 52.9 (CH ₃ ), 52.6 (CH ₃ ), 51.5 (CH), 51.0 (CH), 38.1 (CH ₂ ), 37.3 (CH ₂ ), 23.2 (CH ₃ ), 22.9 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₂ H ₃₃ NO ₁₀ SNa 646.1717, Found 646.1708.

(phenyl 5-acetamido-4,9-di-O-benzimidyl-3,5-dideoxy -7,8-Di-O-methylindole-2-thio-D-propanetriyl-D-galactose-non-2-ketoglucoside methyl ester Methyl(phenyl(5-acetamido-4,9) -di-O-benzoyl-3,5-dideoxy-7,8-di-O-picoloyl-2-thio-D-glycero-D-galacto-non-2-ulopyranoside)onate)(1d)

2-picolinic acid (1.867 g, 15.21 mmol), DMAP (0.074 g, 0.61 mmol) and DCC (3.754 g, 18.21 mmol) were added to the compound containing s6 (3.790 g, 6.07) at 0 °C. Millions of anhydrous dichloroethane (30 ml). The mixture was heated to 40 ° C and stirring was continued at this temperature for 4 hours. The mixture was filtered through a short pad of celite and concentrated in vacuo. The black solid observed on the silica gel was purified by flash column chromatography using ethyl acetate as a solvent to give 4.438 g of white solid 1d , yield 97%: R _f = 0.30 (ethyl acetate); FT-IR (neat) v _max 3275, 3063, 1727, 1680, 1582, 1550, 1442, 1368, 1275, 1119, 1027, 996, 751, 712 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.80-8.78 (m, 1H) , 8.77-8.74 (m, 2H), 8.70-8.69 (m, 1H), 8.18 (d, J = 7.8 Hz, 1H), 8.14 (d, J = 7.8 Hz, 1H), 8.10 (d, J = 7.8) Hz, 1H), 8.05 (d, J = 7.8 Hz, 1H), 7.97-7.76 (m, 8H), 7.63 - 7.32 (m, 12H), 7.13 - 7.09 (m, 1H), 6.21 (d, J = 9.7 Hz, 1H), 6.08 (t, J = 2.4 Hz, 1H), 6.04 (dd, J = 6.4, 1.3 Hz, 1H), 5.99-5.95 (m, 2H), 5.75-5.68 (m, 1H), 5.64 (dt, J=8.4, 2.2 Hz, 1H), 5.19-5.13 (m, 1H), 5.06-5.02 (m, 2H), 4.95 (dd, J = 12.3, 2.4 Hz, 1H), 4.66 (dd, J = 12.3, 6.0 Hz, 1H), 4.54 (dd, J = 12.3, 8.4 Hz, 1H), 4.46 (q, J = 10.1 Hz, 1H), 4.33-4.31 (m, 1H), 4.25 (q, J = 10.1 Hz, 1H), 3.64 (s, 3H), 3.32 (s, 3H), 3.07 (dd, J = 12.9, 4.8 Hz, 1H), 2.94 (dd, J = 13.9, 4.8 Hz, 1H), 2.32 (dd, J = 13.9, 11.8 Hz, 1H), 2.12 (dd, J = 12.9, 11.8 Hz, 1H), 1.80 (s, 3H), 1.78 (s, 3H); ¹³ C NMR (75 MHz, CDCl ₃ ) Δ170.7(C),170.5(C),168.6(C),168.2(C),166.5(C),166.3(C),166.1(C),165.7(C),164.4 (C), 163.9(C), 163.8(C), 150.0(CH), 149.9(CH), 149.6(CH), 147.5(C), 147.1(C), 137.5(CH), 137.4(CH), 137.0 (CH), 136.8 (CH), 136.1 (CH), 133.4 (CH), 132.9 (CH), 129.8 (CH), 129.8 (CH), 129.6 (CH), 129.5 (CH), 129.4 (CH), 129.1 (CH), 128.9 (CH), 128.6 (CH), 128.5 (CH), 128.2 (CH), 127.5 (CH), 127.3 (CH), 127.1 (CH), 126.9 (CH), 125.9 (CH), 125.6 (CH), 88.8 (C), 88.0 (C), 75.5 (CH), 74.8 (CH), 73.3 (CH), 72.7 (CH), 71.0 (CH), 70.6 (CH), 63.2 (CH ₂ ), 62.8 (CH ₂ ), 52.6 (CH ₃ ), 52.6 (CH ₃ ), 49.2 (CH), 49.0 (CH), 37.7 (CH ₂ ), 23.1 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd For C ₄₄ H ₃₉ N ₃ O ₁₂ SNa 856.2147, Found 856.2147.

(phenyl 5-acetamido-4,9-di-O-benzhydryl-3,5-dideoxy-7,8-di-O-nicotinyl-2-ylthio-D- Methyl(phenyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O- Nicotinoyl-2- thio-D-glycero-D-galacto-non-2-ulopyranoside)onate)(1f)

Nicotinic acid (0.246 g, 2.00 mmol), DMAP (0.010 g, 0.08 mmol) and DCC (0.380 g, 2.40 mmol) were added to the compound containing s6 (0.500 g, 0.80 m) at 0 °C. Mohr) in anhydrous dichloroethane (4.0 ml). The mixture was heated to 27 ° C and stirring was continued at this temperature for 1 hour. The mixture was filtered through a short pad of celite and concentrated in vacuo. The yellow solid observed on the silica gel was purified by flash column chromatography using ethyl acetate as a solvent to give 0.621 g of white solid 1f , yield 93%: R _f = 0.38 (ethyl acetate); FT-IR (neat) v _max 3269, 3062, 1728, 1684, 1591, 1543, 1475, 1446, 1369, 1272, 1201, 1109, 1026, 749, 712 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 9.30 (dd, J=2.1, 0.7 Hz, 1H), 9.28 (dd, J=2.1, 0.7 Hz, 1H), 9.21 (dd, J=2.1, 0.7 Hz, 1H), 9.18 (dd, J=2.1, 0.7 Hz, 1H) ), 8.83-8.74 (m, 4H), 8.33-8.29 (m, 2H), 8.26-8.22 (m, 2H), 7.96-7.91 (m, 6H), 7.86-7.84 (m, 2H), 7.63-7.34 (m, 22H), 7.15-7.11 (m, 1H), 5.94 (t, J = 2.0 Hz, 1H), 5.88-5.84 (m, 1H), 5.80 (dd, J = 5.5, 0.7 Hz, 1H), 5.74-5.67 (m, 1H), 5.56 (d, J = 10.0 Hz, 1H), 5.53 (dt, J = 8.5, 2.0 Hz, 1H), 5.37-5.34 (m, 1H), 5.17-5.10 (m, 1H), 4.96-4.88 (m, 3H), 4.65 (dd, J = 12.4, 6.3 Hz, 1H), 4.50 (dd, J = 12.4, 8.6 Hz, 1H), 4.39 (q, J = 10.3 Hz, 1H) ), 4.26-4.20 (m, 2H), 3.69 (s, 3H), 3.54 (s, 3H), 3.04 (dd, J = 12.9, 4.7 Hz, 1H), 2.90 (dd, J = 13.9, 4.9 Hz, 1H), 2.35 (dd, J = 13.9, 11.7 Hz, 1H), 2.17 (dd, J = 12.9, 11.7 Hz, 1H), 1.79 (s, 3H), 1.76 (s, 3H); ¹³ C NMR (100 MHz , CDCl ₃ ) δ170.4 (C), 170.3 (C), 168.5 (C), 168.3 (C), 166.7 (C), 166.6 (C), 166.2 (C) , 165.8(C),165.2(C),164.6(C),164.5(C),164.4(C),153.8(CH),151.3(CH),151.2(CH),151.2(CH),137.6(CH) , 137.5 (CH), 137.4 (CH), 137.4 (CH), 136.9 (CH), 136.2 (CH), 133.6 (CH), 133.6 (CH), 133.3 (CH), 133.1 (CH), 130.3 (CH) , 130.0 (CH), 129.9 (CH), 129.9 (CH), 129.7 (C), 129.6 (CH), 129.6 (C), 129.5 (CH), 129.3 (CH), 129.1 (CH), 128.7 (CH) , 128.7 (CH), 128.6 (C), 128.5 (CH), 128.5 (CH), 128.5 (CH), 128.4 (C), 126.0 (C), 125.7 (C), 125.7 (C), 123.6 (CH) , 123.5 (CH), 89.0 (C), 87.7 (C), 75.8 (CH), 74.5 (CH), 73.7 (CH), 72.1 (CH), 70.7 (CH), 70.4 (CH), 69.9 (CH) , 69.7 (CH), 63.0 (CH ₂ ), 62.7 (CH ₂ ), 53.0 (CH ₃ ), 52.9 (CH ₃ ), 49.9 (CH), 49.7 (CH), 38.5 (CH ₂ ), 38.0 (CH _{2 )} ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₄ H ₃₉ N ₃ O ₁₂ SNa 856.2147, Found 856.2132.

[Phenyl 5-acetamido-4,9-di-O-benzhydryl-3,5-dideoxy-7,8-di-O-isonicotininyl-2-thio-D -Methyl[phenyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O -isonicotinoyl-2-thio-D-glycero-D-galacto-non-2-ulopyrano Side]onate)(1g)

Isonicotinic acid (0.246 grams, 2.00 millimoles), DMAP (0.010 grams, 0.08 millimoles) and DCC (0.380 grams, 2.40 millimoles) were added to the compound containing s6 (0.501 grams, 0.80) at 0 °C. Millions of anhydrous dichloroethane (4.0 ml). The mixture was heated to 40 ° C and stirring was continued at this temperature for 2 hours. The mixture was filtered through a short pad of celite and concentrated in vacuo. Using ethyl acetate as a solvent, the observed yellow solid was purified by flash column chromatography on silica gel to give 0.61 g of white solid 1 g , yield 90%: R _f = 0.33 (ethyl acetate); FT-IR (neat)v _max 3374,3061,1728,1684,1601,1560,1446,1409,1369,1271,1211,1113,1067,1027,997,755,712 cm ^-1 ; ¹ H NMR (400MHz, CDCl ₃ )δ□8.83 -8.74 (m, 8H), 7.95-7.91 (m, 6H), 7.86-7.83 (m, 6H), 7.79-7.78 (m, 4H), 7.63-7.60 (m, 2H), 7.56-7.52 (m, 6H), 7.41-7.28 (m, 12H), 7.18-7.14 (m, 1H), 5.92 (t, J = 2.0 Hz, 1H), 5.87-5.84 (m, 1H), 5.77 (dd, J = 5.5, 0.7 Hz, 1H), 5.73-5.66 (m, 1H), 5.54 (d, J = 10.0 Hz, 1H), 5.49 (dt, J = 8.4, 2.1 Hz, 1H), 5.37 (d, J = 8.2 Hz, 1H), 5.16-5.10 (m, 1H), 4.95-4.88 (m, 3H), 4.64 (dd, J = 12.6, 6.3 Hz, 1H), 4.52 (dd, J = 12.6, 8.4 Hz, 1H), 4.37 (q, J = 10.2 Hz, 1H), 4.21-4.17 (m, 2H), 3.70 (s, 3H), 3.55 (s, 3H), 3.05 (dd, J = 12.9, 4.7 Hz, 1H), 2, 93 (dd, J = 13.9, 4.8 Hz, 1H), 2.34 (dd, J = 13.9, 11.6 Hz, 1H), 2.19 (dd, J = 12.9, 12.0 Hz, 1H), 1.79 (s, 3H), 1.76 (s, 3H); ¹³ C NMR (100MHz, CDCl ₃ ) δ 170.4 (C), 168.4 (C), 168.4 (C), 168.2 (C), 166.7 (C), 166.7 (C), 166.2 (C ), 165.8(C), 165.0(C), 164.5(C), 164.4(C), 164.3(C), 150.8(CH), 150.7(CH), 150.5 (CH), 137.3 (C), 137.0 (CH), 136.9 (C), 136.9 (C), 136.1 (CH), 133.7 (CH), 133.4 (CH), 133.2 (CH), 130.3 (CH), 130.1 (CH), 129.9 (CH), 129.7 (CH), 129.6 (CH), 129.4 (CH), 129.1 (CH), 129.1 (CH), 128.7 (CH), 128.5 (CH), 128.4 (CH), 123.2 (CH), 123.1 (CH), 123.1 (CH), 89.0 (C), 88.9 (C), 87.7 (C), 75.7 (CH), 74.7 (CH), 73.7 (CH), 72.2 (CH), 71.0 (CH), 70.3 (CH), 69.9 (CH), 69.8 (CH), 62.8 (CH ₂ ), 62.5 (CH ₂ ), 52.9 (CH ₃ ), 49.9 (CH), 49.7 (CH), 38.6 ( CH ₂ ), 38.0 (CH ₂ ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₄ H ₃₉ NO ₁₂ SNa 856.2147, Found 856.2153.

1.1.4 Preparation of sialic acid donors 1d and 1b

(Phenyl 5-acetamido-4,9-di-O-benzhydryl-3,5-dideoxy-8-O-methylindole-2-thio-D-propyltriyl- D-galactose-non-2-ketosaccharide Methyl(phenyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-8-O-picoloyl-2-thio-D-glycero-D-galacto-non-2- Ulopyranoside) onate)(s7)

2-picolinic acid (0.151 g, 1.22 mmol), DMAP (0.088 g, 0.07 mmol) and EDC (0.276 g, 1.44 mmol) were added to the compound containing s6 (0.450 g, 0.72) at 0 °C. Millihydrate in anhydrous CH ₂ Cl ₂ (3.6 mL). The mixture was heated to 18 ° C and stirring was continued at this temperature for 20 hours. The reaction mixture was washed with brine then dried over MgSO ₄ The black solid residue was purified by flash column chromatography on ethyl acetate and n-hexane (3:1, by volume), and then eluted with ethyl acetate to give 0.113 g of white solid s6 . 25%, and 0.226 g of a white solid compound s7 , a yield of 43%, and 0.120 g of a white solid compound 1d , yield 20%: R _f =0.20 (ethyl acetate: n-hexane = 3:1 (volume ratio)) ; FT-IR (neat) v _max 3288, 3065, 1726, 1662, 1582, 1539, 1446, 1375, 1263, 1176, 1108, 1069, 1025, 754, 713 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ □ 8.72 (d, J = 2.7 Hz, 1H), 8.16 (d, J = 7.8 Hz, 1H), 8.01 (dd, J = 8.4, 1.3 Hz, 2H), 7.90 (dd, J = 8.4, 1.3 Hz, 2H), 7.80 (td, J = 7.7, 1.7 Hz, 1H), 7.60 (t, J = 7.4 Hz, 1H), 7.53 - 7.35 (m, 8H), 7.18 (t, J = 7.6 Hz, 2H), 7.02 (t, J = 7.4 Hz, 1H), 6.85-6.80 (m, 1H), 5.78-5.72 (m, 1H), 5.54 (dt, J = 8.3, 2.5 Hz, 1H), 4.96 (dd, J = 12.3, 2.0 Hz, 1H), 4.55 (d, J = 10.2 Hz, 1H), 4.28-4.18 (m, 2H), 3.57 (s, 3H), 2.85 (dd, J = 13.8, 4.8 Hz, 1H), 2.35 (dd, J = 13.8, 11.6 Hz, 1H), 1.94 (s, 3H); ¹³ C NMR (75 MHz, CDCl ₃ ) δ 173.3 (C), 168.7 (C), 167.0 (C), 165.9 (C) , 164.6 (C), 150.1 (CH), 149.9 (CH), 149.6 (CH), 147.7 (C), 146.8 (C), 137 .3(CH),137.2(CH),137.1(CH),136.5(CH),136.1(CH),133.9(CH),133.6(CH),133.5(CH),133.1(CH),132.9(CH) , 132.8 (CH), 130.3 (C), 129.9 (CH), 129.8 (CH), 129.6 (CH), 129.1 (CH), 128.9 (CH), 128.8 (CH), 128.7 (CH), 128.4 (CH) , 127.3 (CH), 127.2 (CH), 127.0 (CH), 125.7 (CH), 125.6 (CH), 89.2 (C), 87.8 (C), 76.2 (CH), 75.4 (CH), 74.7 (CH) , 74.4 (CH), 72.4 (CH), 72.1 (CH), 70.3 (CH), 70.0 (CH), 69.7 (CH), 69.3 (CH), 67.7 (CH), 65.2 (CH), 64.0 (CH ₂ ), 63.2 (CH ₂ ), 52.7 (CH ₃ ), 52.3 (CH ₃ ), 51.7 (CH), 51.5 (CH), 37.8 (CH ₂ ), 23.1 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₈ H ₃₆ N ₂ O ₁₁ SNa 751.1932, Found 751.1937.

(Phenyl 5-acetamido-4,7,9-tri-O-benzhydryl-3,5-dideoxy-8-O-methylindole-2-thio-D-propane Methyl(phenyl 5-acetamido-4,7,9-tri-O-benzoyl-3,5-dideoxy-8-O-picoloyl-2- thio-D-glycero-D-galacto-non-2-ulopyranoside) onate)(1b)

Benzoic acid (0.038 g, 0.32 mmol), DMAP (0.003 g, 20.58 micromolar) and DCC (0.085 g, 0.42 mmol) were added to the compound containing s7 (0.150 g, 0.21 mmol) at 0 °C. The ear was in anhydrous CH ₂ Cl ₂ (2.0 mL). The mixture was heated to 40 ° C and stirring was continued at this temperature for 2 hours. The mixture was filtered through a short pad of celite and concentrated in vacuo. Ethyl acetate and CH ₂ Cl ₂ (1:2, by volume) were used as a solvent, and the observed white solid was purified by flash column chromatography to give 0.145 g of white solid 1b , yield: 83%: R _f = 0.45 (ethyl acetate: CH ₂ Cl ₂ = 1:1 (volume ratio)); FT-IR (neat) v _max 3311, 3066, 3011, 2922, 2852, 1729, 1682, 1547, 1444, 1368 , 1272, 1109, 1032, 892, 755, 713, 609 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.80 (d, J = 4.8 Hz, 1H), 8.77 (d, J = 4.1 Hz, 1H), 8.18 (d, J=7.5 Hz, 1H), 8.16 (d, J=8.1 Hz, 1H), 8.07-7.93 (m, 10H), 7.88-7.86 (m, 3H), 7.79 (td, J=7.8, 1.5 Hz, 1H) ), 7.63-7.23 (m, 19H), 7.11 (t, J = 7.4 Hz, 1H), 6.29 (d, J = 8.7 Hz, 1H), 6.08-6.07 (m, 1H), 6.02-6.01 (m, 1H), 5.96-5.90 (m, 2H), 5.79-5.68 (m, 2H), 5.60-5.58 (m, 1H), 5.30-5.24 (m, 1H), 5.02-4.95 (m, 1H), 4.68 ( Dd, J = 12.3, 6.2 Hz, 1H), 4.52 (dd, J = 12.3, 8.7 Hz, 1H), 4.42 (q, J = 10.2 Hz, 1H), 4.34 - 4.32 (m, 1H), 4.16 (q) , J = 10.6 Hz, 1H), 3.63 (s, 3H), 3.36 (s, 3H), 3.09 (dd, J = 12.5, 4.6 Hz, 1H), 2.94 (dd, J = 13.8, 4.5 Hz, 1H) , 2.31 (dd, J = 13.8, 11.6 Hz, 1H), 2.13 (dd, J = 12.5, 11.5 Hz, 1H), 1.82 (s, 3H), 1.79 (s, 3H); ¹³ C NMR (100 MHz, CDCl) ₃ ) δ170.5(C), 168.6(C), 166.6(C), 165.8(C), 165.5(C),164. 4(C), 150.0(CH), 147.2(C), 137.5(CH), 136.0(CH), 133.4(CH), 133.2 (CH), 132.9(CH), 129.9(CH), 129.9(CH), 129.8(C),129.7(CH),129.5(CH),129.4(CH),129.0(CH),128.7(C),128.6(CH),128.5(CH),128.3(CH),128.2(CH), 127.5 (CH), 125.8 (CH), 88.6 (C), 75.1 (CH), 73.2 (CH), 70.8 (CH), 70.0 (CH), 63.2 (CH ₂ ), 52.7 (CH ₃ ), 49.2 (CH) ), 37.7 (CH ₂ ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₅ H ₄₀ N ₂ O ₁₂ SNa 855.2194, Found 855.2181.

1.1.5 Preparation of sialic acid donor 1h

(Phenyl 4,9-di-O-benzhydryl-5-benzyloxyacetamido-3,5-dideoxy-2-thio-D-propyltriyl-D-semi-milk-non- Methyl(phenyl 4,9-di-O-benzoyl-5-benzyloxyacetamido-3,5-dideoxy-2-thio-D-glycero-D-galacto-non-2-ulopyranoside) onate (s9); and (phenyl 4,8,9-tri-O-benzhydryl-5-benzyloxyacetamido-3,5-dideoxy-8-O-methylindole-2 -thio-D-propyltriyl-D-galacto-non-2-ketoglucoside) methyl ester (Methyl(phenyl 4,8,9-tri-O-benzoyl-5-benzyloxyacetamido-3,5-dideoxy-8-O-picoloyl-2-thio-D-glycero-D-galacto-non-2-ulopyranoside) Onate)(s10)

At 0 ° C, benzoic anhydride (3.637 grams, 16.08 millimoles) was added to contain the compound s8 (2.100 grams, 4.02 millimoles), Im (1.368 grams, 20.11 millimoles) and DMAP (0.245 grams, 2.01 milliliters). Mohr) in anhydrous dichloroethane (40 ml). The mixture was heated to 40 ° C and stirred at this temperature for 2.5 hours. 6N HCl was added after the reaction was quenched on ice, extracted with ethyl acetate, then washed again with ₂ CO ₃ solution and saturated brine and ice K, dried over MgSO ₄ to treatment, and concentrated in vacuo. Ethyl acetate and n-hexane (1:1→3:1, by volume) were used as the extract, and the obtained white solid residue was purified by flash column chromatography to obtain 2.143 g of white solid compound s9 . Yield 73%, and 0.793 g of white solid compound s10 , yield 21%: s9 : R _f = 0.13 (ethyl acetate: CH ₂ Cl ₂ = 1:1 (volume ratio)); mp = 99-100 ° C; [α] ²⁴ _D -28.7 (c 0.32, CHCl ₃ ); FT-IR (neat) v _max 3343, 3064, 2951, 1719, 1665, 1602, 1534, 1447, 1375, 1313, 1273, 1117, 1070, 1026 , 994, 895, 753, 713, 618 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.06-8.00 (m, 4H), 7.62-7.59 (m, 3H), 7.50-7.43 (m, 4H), 7.33-7.29 (m, 6H) ), 7.25-7.23 (m, 2H), 7.16 (d, J = 8.5 Hz, 1H), 5.85 (ddd, J = 13.8, 8.7, 4.7 Hz, 1H), 4.72 (dd, J = 11.8, 2.4 Hz, 1H), 4.57 (d, J = 5.6 Hz, 1H), 4.52-4.44 (m, 4H), 4.31-4.23 (m, 1H), 4.15-4.11 (m, 1H), 3.91 (d, J = 15.6 Hz) , 1H), 3.82 (d, J = 15.6 Hz, 1H), 3.64 - 3.62 (m, 1H), 3.57 (s, 31-1), 2.89 (dd, J = 13.8, 4.7 Hz, 1H), 2.44 ( Bs, 1H), 2.37 (dd, J = 13.8, 11.8 Hz, 1H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 172.6 (C), 171.0 (C), 168.5 (C), 167.3 (C), 166.6(C), 136.4(C), 135.7(CH), 133.7(CH), 133.6(CH), 133.1(CH), 130.2(CH) ,130.1(CH),129.9(CH),129.7(CH),129.7(CH),129.5(CH),129.1(CH),129.0(CH),128.6(CH),128.5(CH),128.4(CH) , 128.3 (CH), 127.8 (CH), 89.1 (C), 73.5 (CH ₂ ), 73.0 (CH), 69.4 (CH), 69.3 (CH), 68.9 (CH), 68.6 (CH ₂ ), 67.5 ( CH ₂ ), 52.7 (CH ₃ ), 51.2 (CH), 38.0 (CH ₂ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₉ H ₃₉ NO ₁₁ SNa 752.2136, Found 752.2118; s10 :R _f =0.45 (ethyl acetate: CH ₂ Cl ₂ = 1:1 (volume ratio)); mp = 115-117 ° C; [α] ²⁴ _D -48.6 (c 0.15, CHCl ₃ ); FT-IR (neat) v _max 3341 , 3065, 1718, 1603, 1538, 1449, 1271, 1172, 1112, 1071, 1026, 890, 749, 711 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.11-8.09 (m, 2H), 8.03-8.01 (m , 2H), 7.92-7.90 (m, 2H), 7.64-7.59 (m, 2H), 7.57-7.42 (m, 8H), 7.41-7.36 (m, 2H), 7.31-7.27 (m, 4H), 7.22 -7.19 (m, 2H), 7.08-7.04 (m, 1H), 5.91-5.84 (m, 1H), 5.49 (ddd, J = 8.0, 3.4, 2.0 Hz, 1H), 4.95 (dd, J = 12.3, 2.0 Hz, 1H), 4.66 (dd, J = 12.3, 8.0 Hz, 1H), 4.53-4.46 (m, 3H), 4.29 (d, J = 10.3, 8.4 Hz, 1H), 4.07 (dd, J = 3.4) , 1.5 Hz, 1H), 3.96-3.83 (m, 2H), 3.56 (s, 3H), 2.88 (dd, J = 13.8, 4.8 Hz, 1H), 2.40 (dd, J = 13.8, 11.8 Hz, 1H) ¹³ C NMR (75 MHz, CDCl ₃ ) δ 173.1 (C), 171.0 (C), 168.7 (C), 166.6 (C), 166.4 (C), 166. 0(C), 136.5(C), 136.2(CH), 133.8(CH), 133.6(CH), 133.3(CH), 132.9(CH), 130.3(CH), 130.2(CH), 130.1(CH), 130.0 (CH), 129.9 (CH), 129.8 (CH), 129.6 (CH), 129.1 (CH), 128.9 (CH), 128, 7 (CH), 128.6 (CH), 128.5 (CH), 128.3 (CH) ), 128.2 (CH), 127.8 (CH), 89.4 (C), 74.5 (CH), 74.3 (CH), 73.5 (CH ₂ ), 69.9 (CH), 68.9 (CH), 68.7 (CH ₂ ), 64.1 (CH ₂ ), 52.6 (CH ₃ ), 51.1 (CH), 37.8 (CH ₂ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₄₆ H ₄₃ NO ₁₂ SNa 856.2398, Found 856.2419.

(Phenyl 4,9-di-O-benzhydryl-5-benzyloxyacetamido-3,5-dideoxy-7,8-di-O-methylindole-2-thio- Methyl(phenyl 4,9-di-O-benzoyl-5-benzyloxyacetamido-3,5-dideoxy-7,8-di- O-picoloyl-2-thio-D-glycero-D-galacto-non-2-ulopyranoside)onate)(1h)

2-picolinic acid (0.758 grams, 6.15 millimoles), DMAP (0.030 grams, 0.25 millimoles) and DCC (1.524 grams, 7.38 millimoles) were added to the compound containing s9 (1.795 grams, 2.46) at 0 °C. Monomolar in anhydrous dichloroethane (12 ml). The mixture was heated to 32 ° C and stirring was continued at this temperature for 1 hour. The mixture was filtered through a short pad of celite and concentrated in vacuo. Ethyl acetate and n-hexane (3:1→6:1, by volume) were used as the extract, and the observed yellow solid was purified by silica gel column chromatography to afford 2.126 g of white solid 1b , yield 92%. : R _f = 0.20 (ethyl acetate: CH ₂ Cl ₂ = 4:1 (volume ratio)); mp = 139-140 ° C; [α] ²⁴ _D + 52.7 (c 0.15, CHCl ₃ ); FT-IR ( Neat)v _max 3359,3063,3008,2956,1726,1685,1602,1585,1527,1452,1439,1275,1118,1027,994,893,751,712,619cm ^-1 ; ¹ H NMR (400MHz, CDCl ₃ )δ 8.78-8.75 (m, 2H), 8.15 (dt, J = 7.9, 1.0 Hz, 1H), 8.04 (dt, J = 7.9, 1.0 Hz, 1H), 7.95-7.92 (m, 2H), 7.87-7.83 (m, 3H) ), 7.77 (td, J = 7.9, 1.8 Hz, 1H), 7.56-7.50 (m, 4H), 7.49-7.42 (m, 2H), 7.39-7.28 (m, 7H), 7.21-7.18 (m, 2H) ), 7.14-7.10 (m, 1H), 6.81 (d, J = 10.3 Hz, 1H), 6.03 (t, J = 2.3 Hz, 1H), 5.71 (ddd, J = 11.4, 10.0, 4.8 Hz, 1H) , 5.66 (dt, J = 8.4, 2.3 Hz, 1H), 5.04 (dd, J = 10.9, 2.5 Hz, 1H), 4.95 (dd, J = 12.3, 2.5 Hz, 1H), 4.54-4.49 (m, 3H) ), 4.45 (q, J = 10.0 Hz, 1H), 3.90-3.64 (m, 5H), 2.97 (dd, J = 13.9, 4.8 Hz, 1H), 2.32 (dd, J = 13.9, 11.4 Hz, 1H) ¹³ C NMR (75 MHz, CDCl ₃ ) δ 170.5 (C), 168.5 (C), 166.1 (C), 165.7 (C), 164.3 (C), 164.0 (C), 150.1 (CH), 150.0 (CH) ), 147.6(C), 147.3(C) , 137.2 (CH), 136.9 (CH), 136.9 (CH), 136.1 (CH), 133.3 (CH), 132.8 (CH), 129.8 (CH), 129.8 (CH), 129.5 (CH), 129.3 (CH) , 129.2 (CH), 128.5 (CH), 128.3 (CH), 128.2 (CH), 127.7 (CH), 127.7 (CH), 127.6 (CH), 127.2 (CH), 126.9 (CH), 125.7 (CH) , 125.5 (CH), 88.8 (C), 74.4 (CH), 73.2 (CH), 73.2 (CH ₂ ), 71.3 (CH), 70.1 (CH), 69.3 (CH ₂ ), 63.5 (CH ₂ ), 52.6 (CH ₃ ), 48.9 (C), 37.8 (CH ₂ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₅₁ H ₄₅ N ₃ O ₁₃ SNa 962.2565, Found 962.2550.

1.2 Coupling the sialic acid donor of Example 1 with a glucosyl acceptor

In this example, the sialic acid donors of Example 1 (i.e., Compounds 1a-e) were respectively coupled to a glucoside receptor 2 according to the following conditions, and the products were isolated (i.e., Compounds 3a-e and 4a). After -e), the analysis was carried out by ¹ H-NMR. Table 1 illustrates the results of the analysis.

General Saccharification Procedure : Anhydrous CH ₂ comprising the sialic acid donor of Example 1 (1.0 eq.), the acceptor (1.2 eq.), and the activated 3 Å powdered molecular sieve (1.0 gram per millimole) was stirred in a nitrogen atmosphere at room temperature. The mixture of Cl ₂ (0.05 M) was allowed to stand for 1 hour to remove residual water. After the temperature of the reaction mixture was lowered to -40 ° C, N -iodosuccinimide (NIS) (2 equivalents) and TfOH (1.5 equivalents) were added. Stirring was continued at this temperature until a thin-layer liquid chromatography (TLC) showed that the reaction was complete. After the reaction was stopped by the addition of triethylamine, the mixture was filtered through a short pad of diatomaceous earth. After washed with saturated Na ₂ S ₂ O ₃ solution was washed with brine and the product was dried in MgSO _4, filtered, and was concentrated in vacuo.

Disaccharide 3a and olefin 4a

Methyl 5-acetamido-4,8,9-tri-O-benzhydryl-3,5-dideoxy-7-O-methylindole-D-propyltriyl-D-half -N--2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (Methyl 5-acetamido-4,8,9-tri-O -benzoyl- 3,5-dideoxy-7-O-picoloyl-D-glycero-D-galacto-non-2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-pipeper "Glycosidine" (3a); and 5-acetamido-2,6-anhydro-4,8,9-tri-O-benzhydryl-3,5-dideoxy-7-O-methylindole碇-D-propyltriyl-D-galacto-non-ketoic acid methyl ester (5-acetamido-2,6-anhydro-4,8,9-tri-O-benzoyl-3,5-dideoxy- 7-O-picoloyl-D-glycero-D-galacto-non-2-enonate)(4a)

CH ₂ Cl ₂ (7.0 ml) containing NIS (0.162 g, 0.72 mmol) and TfOH (0.048 g, 0.54 mmol) was added to the thiosialin 1a (0.304 g, 0.36 mmol) according to the general procedure. The reaction was carried out for 2 hours in a glyphoside receptor 2 (0.201 g, 0.43 mmol) and activated 3Å powdered molecular sieve (0.360 g). Using ethyl acetate and CH ₂ Cl ₂ (1:2, by volume) as a solvent, the pale yellow slurry residue obtained by purifying the silica gel by flash column chromatography gave 0.243 g of a colorless syrupy disaccharide 3a. , yield 57%, and 0.104 g of the colorless syrupy sugar 4a , yield 40%: 3a : R _f = 0.23 (ethyl acetate: CH ₂ Cl ₂ = 1:2 (volume ratio)); FT-IR ( Neat)v _max 3064,3031,2934,1723,1685,1602,1452,1364,1312,1278,1214,1165,1114,1025,751,713cm ^-1 ; ¹ H NMR (400MHz, CDCl ₃ )δ 8.81-8.80 (m, 1H), 8.70-8.69 (m, 1H), 8.21 (td, J = 4.3, 0.9 Hz, 1H), 8.18-8.16 (m, 1H), 8.00-7.85 (m, 8H), 7.66 (td , J = 7.7, 1.7 Hz, 1H), 7.55-7.27 (m, 29H), 6.01 (t, J = 1.5 Hz, 1H), 5.94 (td, J = 5.6, 1.6 Hz, 1H), 5.89 (dd, J=8.3, 2.0 Hz, 1H), 5.58 (dd, J = 12.3, 2.4 Hz, 1H), 5.55-5.48 (m, 1H), 5.42-5.38 (m, 1H), 5.26-5.20 (m, 1H) , 5.02-4.63 (m, 11H), 4.53 (dd, J = 10.9, 2.0 Hz, 1H), 4.40 (q, J = 10.3 Hz, 1H), 4.32 (dd, J = 10.3, 4.6 Hz, 1H), 4.09 (d, J = 10.7 Hz, 1H), 4.05-3.99 (m, 1H), 3.95 (d, J = 10.7 Hz, 1H), 3.77 (s, 3H), 3.72 (dd, J = 9.5, 3.5 Hz) , 1H), 3.67 (dd, J = 10.9, 2.4 Hz, 1H), 3.61 (t, J = 9.5 Hz, 1H), 3.53 (dd, J = 9.9, 3.5 Hz, 1H), 3.38 (s, 3H) , 3.31 (s, 3H), 2.85 (dd, J = 12.7, 4.8 Hz, 1H ), 2.76 (dd, J = 12.9, 5.0 Hz, 1H), 2.08 (dd, J = 12.9, 11.4 Hz, 1H), 1.79 (s, 3H), 1.77 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ170.2 (C), 167.4 (C), 166.4 (C), 166.2 (C), 166.0 (C), 165.9 (C), 164.0 (C), 150.1 (CH), 147.6 (C), 138.9(C), 138.5(C), 138.5(C), 137.1(CH), 133.3(CH), 133.2(CH), 133.0(CH), 129.9(CH), 129.7(CH), 129.5(CH), 129.4 (CH), 128.5 (CH), 128.4 (CH), 128.4 (CH), 128.4 (CH), 128.3 (CH), 128.3 (CH), 128.8 (CH), 128.0 (CH), 127.9 (CH), 127.9 (CH), 127.7 (CH), 127.7 (CH), 127.5 (CH), 127.0 (CH), 125.6 (CH), 98.3 (C), 97.9 (CH), 82.2 (CH), 80.3 (CH), 75.8(CH ₂ ),75.2(CH ₂ ),74.2(CH),73.2(CH ₂ ),72.1(CH),71.4(CH),69.8(CH),69.2(CH),63.5(CH ₂ ),62.4 (CH ₂ ), 55.0 (CH), 52.8 (CH), 49.7 (CH), 38.0 (CH ₂ ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₆₇ H ₆₆ N ₂ O ₁₈ Na 1209.4203, Found 1209.4214; 4a : R _f =0.20 (ethyl acetate: CH ₂ Cl ₂ = 1:2 (volume ratio)); [α] ²⁴ _D -99.0 (c 0.45, CHCl ₃ ); FT-IR (neat) v _max 3320, 3063, 3006, 2931, 2851, 1727, 1664, 1593, 1541, 1445, 1372, 1269, 1107, 1022, 756, 713 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.74- 8.71 (m, 1H), 8.13 (d, J = 7.8 Hz, 1H), 8.01 - 7.96 (m, 6H), 7.82 (t, J = 7.8 Hz, 1H), 7.59-7.30 (m, 10H), 6.33 (d, J = 5.7 Hz, 1H), 6.23-6.20 (m, 2H), 6.09-6.06 (m, 1H), 5.54 (dd, J = 5.7, 3.9 Hz, 1H), 5.30 (dd, J = 12.4, 2.8 Hz, 1H), 4.86 (ddd, J = 12.4, 8.6, 3.9 Hz, 1H), 4.76 - 4.70 (m, 2H), 3.80 ( s, 3H), 1.87 (s, 3H); ¹³ C NMR (100MHz, CDCl ₃ ) δ 170.1 (C), 166.2 (C), 166.1 (C), 165.4 (C), 163.8 (C), 161.8 (C) ), 150.0 (CH), 147.1 (C), 146.6 (C), 137.1 (CH), 133.5 (CH), 133.4 (CH), 133.0 (CH), 129.8 (CH), 129.8 (CH), 129.7 (CH) ), 129.6 (CH), 129.3 (CH), 128.5 (CH), 128.5 (CH), 128.3 (CH), 127.2 (CH), 125.6 (CH), 106.2 (CH), 74.3 (CH), 72.5 (CH) ), 70.3 (CH), 65.1 (CH), 63.2 (CH ₂ ), 52.6 (CH ₃ ), 45.2 (CH), 23.1 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₉ H ₃₄ N ₂ O ₁₂ Na 745.2004, Found 745.2005.

Disaccharide 3b and olefin 4b

Methyl 5-acetamido-4,7,9-tri-O-benzhydryl-3,5-dideoxy-8-O-methylindole-D-propyltriyl-D-half -N--2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (Methyl 5-acetamido-4,7,9-tri-O -benzoyl-3,5-dideoxy-8-O-picoloyl-D-glycero-D-galacto- Non-2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-haloglucoside) (3b); and 5-acetamido-2,6-dehydration -4,7,9-tri-O-benzimidyl-3,5-dideoxy-8-O-methylindole-D-propyltriyl-D-galacto-non-2-ketoic acid Ester (methyl 5-acetamido-2,6-anhydro-4,7,9-tri-O-benzoyl-3,5-dideoxy-8-O-picoloyl-D-glycero-D-galacto-non-2-enonate ) (4b)

According to the general procedure, CH ₂ Cl ₂ (1.2 ml) containing NIS (0.027 g, 0.12 mmol) and TfOH (0.008 ml, 90.03 mmol) was added to the thiosialin 1b (0.050 g, 60.02 micromolar) ), a p-glucoside receptor 2 (0.033 g, 72.03 micromoles) and activated 3Å powdered molecular sieves (0.060 g) were reacted for 2 hours. Using acetone and Et ₂ O (1:6, by volume) as the extract, the pale yellow slurry residue obtained by purifying the silica gel by flash column chromatography gave 0.044 g of a colorless syrupy disaccharide 3b . 62%, and 0.010 g of colorless syrupy 4b , yield 24%: 3b : R _f = 0.43 (acetone: n-hexane = 1:1 (volume ratio)); FT-IR (neat) v _max 3306, 2920 , 2854, 1728, 1641, 1548, 1458, 1275, 1084, 751, 711 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.76 (d, J = 4.2 Hz, 1H), 8.07 (d, J = 7.8 Hz) , 1H), 7.97-7.90 (m, 6H), 7.80 (td, J = 7.7, 1.5 Hz, 1H), 7.55-7.47 (m, 4H), 7.39-7.24 (m, 18H), 7.18-7.12 (m , 3H), 5.99-5.89 (m, 2H), 5.52 (d, J = 9.7 Hz, 1H), 5.11-4.93 (m, 3H), 4.86-4.75 (m, 3H), 4.69-4.64 (m, 2H) ), 4.49-4.45 (m, 2H), 4.38 (dd, J = 10.2, 3.7 Hz, 1H), 4.27 (q, J = 10.2 Hz, 1H), 4.11 (dd, J = 12.5, 6.2 Hz, 1H) , 3.99 (t, J = 9.2 Hz, 1H), 3.84-3.31 (m, 1H), 3.67 (t, J = 9.4 Hz, 1H), 3.59 (dd, J = 10.4, 1.7 Hz, 1H), 3.54 ( Dd, J=9.7, 3.4 Hz, 1H), 3.48 (s, 3H), 3.38 (s, 3H), 2.86 (dd, J = 12.7, 4.5 Hz, 1H), 2.10 (t, J = 12.7 Hz, 1H) ), 1.79 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 170.1 (C), 168.0 (C), 166.5 (C), 166.1 (C), 165.6 (C), 163.9 (C), 149.7 (CH), 148.2 (C), 139.1 (C), 138.5 (C), 138.4 (C), 137.1 (CH), 133.5 (CH), 133.4 (CH), 133.1 (CH), 130.0 (CH), 129.9 (CH), 129.9 (C), 129.6 (C), 129.4 (C), 128.6 (CH), 128.6 (CH), 128.5 (CH), 128.5 (CH), 128.4 (CH), 128.3 (CH), 128.1 (CH), 128.0 (CH), 127.7 (CH), 127.7 (CH), 127.0 (CH), 125.7 (CH), 125.7 (CH), 99.2 (C), 98.3 (CH), 82.2 (CH), 79.6 (CH), 75.9 (CH ₂ ), 74.9 (CH ₂ ), 73.5 (CH ₂ ), 72.8 (CH), 70.1 (CH), 69.7 (CH), 69.7 (CH), 68.2 (CH), 63.7 (CH ₂ ), 63.1 (CH ₂ ), 55.3 (CH ₃ ), 52.6 (CH ₃ ) 49.8(CH),38.5(CH ₂ ),30.5(CH ₃ ),23.3(CH ₃ );HRMS-ESI[M+Na] ⁺ Calcd for C ₆₇ H ₆₆ N ₂ O ₁₈ Na 1209.4203,Found 1209.4181; 4b : R _f =0.38 (acetone: n-hexane = 1:1 (volume ratio)); [α] ³⁰ _D +126.7 (c 0.20, CHCl ₃ ); FT-IR (neat) v _max 3277, 3066, 3016, 2960 , 2925, 2855, 1729, 1671, 1593, 1546, 1445, 1368, 1262, 1104, 1029, 989, 908, 857, 755, 711, 610 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.67 (d, J = 4.4 Hz, 1H) , 8.09 (d, J = 7.4 Hz, 2H), 8.06 (d, J = 7.9 Hz, 1H), 7.98 (t, J = 6.4 Hz, 4H), 7.81 (t, J = 7.7 Hz, 1H), 7.59 (t, J = 7.4 Hz, 1H), 7.54 - 7.45 (m, 5H), 7.40 - 7.35 (m, 4H), 7.00 (bs, 1H), 6.17 (dd, J = 5.0, 2.3 Hz, 1H), 6.09 (d, J = 2.3 Hz, 1H), 6.07-6.04 (m, 1H), 5.93 (dd, J = 8.8, 2.3 Hz, 1H), 5.25 (dd, J = 12.4, 2.9 Hz, 1H), 4.94 (dd, J = 10.7, 1.4 Hz, 1H), 4.72-4.60 (m, 2H), 3.77 (s, 3H), 1.84 (s, 3H); ¹³ C NMR (100MHz, CDCl ₃ ) δ170.4 (C), 166.6 (C), 166.3 (C), 165.7 (C), 164.1 (C), 161.9 (C), 149.9 (CH), 147.2 (C), 145.5 ( C), 137.6 (CH), 133.5 (CH), 133.5 (CH), 133.2 (CH), 130.1 (CH), 130.0 (CH), 129.8 (CH), 129.6 (C), 129.5 (C), 128.7 ( CH), 128.6 (CH), 128.5 (CH), 127.6 (CH), 125.9 (CH), 109.0 (CH), 76.9 (CH), 73.4 (CH), 70.2 (CH), 68.9 (CH), 63.0 ( CH ₂ ), 52.6 (CH ₃ ), 47.2 (CH), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₉ H ₃₄ N ₂ O ₁₂ Na 745.2004, Found 745.2005.

Disaccharide 3c and olefin 4c

Methyl 5-acetamido-7.8-di-O-benzhydryl-3,5-dideoxy-4,9-di-O-methylindole-D-propyltriyl-D-half -N-2-phenylpyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (Methyl 5-acetamido-7.8-di-O-benzoyl-3 ,5-dideoxy-4,9-di-O-picoloyl-D-glycero-D-galacto-non-2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α- D-glucopyranoside) (3c); and 5-acetamido-2,6-anhydro-7,8-di-O-benzimidyl-3,5-di Oxygen-4,9-di-O-methylindole-D-propyltriyl-D-galactose-methyl-2-acetamido-2,6-anhydro-7,8- di-O-benzoyl-3,5-dideoxy-4,9-di-O-picoloyl-D-glycero-D-galacto-non-2-enonate)(4c)

According to the general procedure, CH ₂ Cl ₂ (1.9 ml) containing NIS (0.043 g, 0.19 mmol) and TfOH (0.013 ml, 0.14 mmol) was added to the thiosialin 1c (0.080 g, 0.10 mmol). ), glucopyranoid receptor 2 (0.060 g, 0.12 mmol) and activated 3Å powdered molecular sieve (0.120 g), reacted for 2 hours. Using ethyl acetate and acetone/CH ₂ Cl ₂ (1/1, by volume) as the extract, the pale yellow slurry residue obtained by purifying the silica gel by flash column chromatography gave 0.049 g of a colorless paste. Sugar 3c , yield 43%, and 0.034 g of colorless syrupy sugar 4c , yield 43%: 3c : R _f = 0.13 (ethyl acetate); FT-IR (neat) v _max 3326, 2922.2854, 1733, 1678 , 1546, 1446, 1366, 1280, 1095, 752, 708, 613 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.79 (d, J = 4.3 Hz, 1H), 8.76 (d, J = 4.9 Hz, 1H), 8.74 (d, J = 4.7 Hz, 2H), 8.12 (dd, J = 7.4 Hz, 2H), 8.06-7.93 (m, 12H), 7.81-7.77 (m, 4H), 7.70 (td, J = 7.8, 1.5 Hz, 1H), 7.62-7.30 (m, 37H), 7.23-7.22 (m, 6H), 6.29 (dd, J = 8.6, 7.6 Hz, 1H), 5.97-5.86 (m, 4H), 5.75-5.68 (m, 1H), 5.55 (dd, J = 11.9, 3.7 Hz, 1H), 5.44 - 5.37 (m, 1H), 4.97 - 4.58 (m, 20H), 4.38 (dd, J = 12.2, 5.8 Hz, 1H) ), 4.34 (q, J = 10.0 Hz, 1H), 4.22 (q, J = 9.8 Hz, 1H), 4.15 (dd, J = 10.4, 4.5 Hz, 1H), 4.05 (d, J = 10.5 Hz, 1H) ), 4.00-3.92 (m, 2H), 3.85 (d, J = 11.0 Hz, 1H), 3.80-3.78 (m, 2H), 3.73-3.70 (m, 4H), 3.61-3.57 (m, 2H), 3.52-3.47 (m, 3H), 3.43 (s, 3H), 3.34 (s, 6H), 2.82 (dd, J = 12.6, 4.9 Hz, 1H), 2.72 (dd, J = 13.1, 5.0 Hz, 1H) , 2.16-2.08 (m, 2H), 1.81 (s, 3H), 1.78 (s, 3H) _{^{13 C NMR (100MHz, CDCl 3}} ) δ170.5 (C), 170.4 (C), 170.0 (C), 167.4 (C), 166.2 (C), 165.7 (C), 165.6 (C), 165.5 (C) , 164.6 (C), 164.5 (C), 164.5 (C), 164.3 (C), 150.2 (CH), 150.1 (CH), 150.0 (CH), 147.6 (C), 147.5 (C), 147.4 (C) , 147.2(C), 139.0(C), 138.8(C), 138.6(C), 138.6(C), 138.4(C), 138.3(C), 137.4(CH), 137.3(CH), 137.2(CH) , 137.1 (CH), 133.3 (CH), 133.1 (CH), 130.0 (CH), 129.9 (CH), 129.8 (C), 129.7 (C), 129.5 (C), 128.6 (CH), 128.5 (CH) , 128.4 (CH), 128.4 (CH), 128.3 (CH), 128.2 (CH), 128.1 (CH), 128.0 (CH), 127.9 (CH), 127.8 (CH), 127.7 (CH), 127.7 (CH) , 127.6 (CH), 127.3 (CH), 127.2 (CH), 125.7 (CH), 125.6 (CH), 125.4 (CH), 125.0 (CH), 99.1 (C), 98.2 (C), 98.1 (CH) , 98.0 (CH), 82.3 (CH), 82.0 (CH), 80.1 (CH), 79.7 (CH), 77.6 (C), 77.4 (C), 75.8 (CH ₂ ), 75.8 (CH ₂ ), 75.2 ( CH ₂ ), 74.9 (CH ₂ ), 73.9 (CH), 73.4 (CH ₂ ), 73.2 (CH ₂ ), 72.5 (CH), 71.5 (CH), 71.0 (CH), 70.8 (CH), 70.7 (CH) ), 69.6 (CH), 69.5 (CH), 69.4 (CH), 69.4 (CH), 64.0 (CH ₂ ), 63.7 (CH ₂ ), 63.6 (CH ₂ ), 62.6 (CH ₂ ), 55.2 (CH _{3 )} ), 55.1 (CH ₃ ), 52.8 (CH ₃ ), 52.5 (CH ₃ ), 50.1 (CH), 49.9 (CH), 38.3 (CH ₂ ), 37.9 (CH ₂ ), 23.2 (CH ₃ ), 23.2 ( CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₆₆ H _{6 5} N ₃ O ₁₈ Na 1210.4155, Found 1210.4135; 4c : R _f =0.13 (ethyl acetate); [α] ³⁰ _D +162.8 (c 0.31, CHCl ₃ ); FT-IR (neat) v _max 3318, 3064, 3006, 2923, 2853, 1732, 1673, 1578, 1545, 1444, 1369, 1254, 1100, 1035, 991, 907, 855, 755, 711, 614 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.85 (d, J = 4.0 Hz, 1H ), 8.72 (d, J = 4.3 Hz, 1H), 8.10 (d, J = 8.0 Hz, 4H), 7.94 (d, J = 8.0 Hz, 2H), 7.83 (td, J = 8.0, 1.2 Hz, 1H) ), 7.78 (td, J = 8.0, 1.2 Hz, 1H), 7.60 (t, J = 7.5 Hz, 1H), 7.53 - 7.43 (m, 5H), 7.35 (t, J = 7.7 Hz, 2H), 7.13 (d, J = 9, 3 Hz, 1H), 6.17 (dd, J = 8.4, 2.5 Hz, 1H), 6.11 (t, J = 3.4 Hz, 1H), 6.07 (d, J = 2.6 Hz, 1H), 6.00-5.97 (m, 1H), 5.19 (dd, J = 12.2, 3.4 Hz, 1H), 5.06 (dd, J = 10.5, 2.8 Hz, 1H), 4.75 (dd, J = 12.2, 5.9 Hz, 1H) , 4.53 (q, J = 9.5 Hz, 1H), 3.65 (s, 3H), 1.89 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 171.8 (C), 165.6 (C), 165.6 ( C), 164.9 (C), 164.7 (C), 161.8 (C), 150.1 (CH), 150.0 (CH), 147.4 (C), 147.0 (C), 145.7 (C), 137.5 (CH), 137.3 ( CH), 133.4 (CH), 133.3 (CH), 130.0 (CH), 129.8 (CH), 129.5 (C), 129.3 (C), 128.6 (CH), 128.4 (CH), 127.5 (CH), 127.3 ( CH), 125.9 (CH), 125.4 (CH), 108.3 (CH), 76.6 (CH), 71.4 (CH), 71.2 (CH), 69.1 (CH), 64.2 (CH ₂ ), 52.5 (CH ₃ ), 47.0 (CH), 23.1 (C H ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₃₈ H ₃₃ N ₃ O ₁₂ Na 746.1956, Found 746.1952.

Disaccharide 3d and olefin 4d

Methyl 5-acetamido-4,9-di-O-benzylidene -3,5-dideoxy-7,8-di-O-methylindole-D-propyltriyl-α-D-galactose-non-2-ulopyranosylonate-(2→6)-methyl 2, 3,4-Tri-O-benzyl-α-D-glucopyranoside (Methyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O-picoloyl- D-glycero-α-D-galacto-non-2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside)(3d); and 5-acetamidine Amino-2,6-anhydro-4,9-di-O-benzhydryl-3,5-dideoxy-7,8-di-O-methylindole-D-propyltriyl-D- Methyl 5-acetamido-2,6-anhydro-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O-picoloyl-D -glycero-D-galacto-non-2-enonate)(4d)

According to the general procedure, CH ₂ Cl ₂ (0.7 ml) containing NIS (0.016 g, 71.94 micromoles) and TfOH (0.002 ml, 53.96 micromoles) was added to the thiosialin 1d (0.030 g, 35.97 micromolar) ), glucopyranoid receptor 2 (0.020 g, 43.16 micromoles) and activated 3Å powdered molecular sieve (0.040 g), reacted for 2 hours. Using ethyl acetate as the extract, the pale yellow slurry residue obtained by purifying the silica gel by flash column chromatography gave 0.030 g of white solid disaccharide 3d , yield 70%, and 0.007 g of white solid olefinic sugar 4d. Yield: 27%: 3d : R _f = 0.28 (ethyl acetate); mp = 11.11 - 112 ° C; [α] ²⁴ _D + 52.4 (c 0.35, CHCl ₃ ); FT-IR (neat) v _max 3330, 3062, 3008, 2926, 1730, 1678, 1579, 1446, 1366, 1280, 1121, 752, 709 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.73 (d, J = 4.4 Hz, 1H), 8.66 (d) , J = 4.2 Hz, 1H), 8.06 (d, J = 7.8 Hz, 1H), 7.98-7.90 (m, 5H), 7.79 (td, J = 7.7, 1.6 Hz, 1H), 7.64 (td, J = 7.7, 1.7 Hz, 1H), 7.54-7.46 (m, 3H), 7.42-7.29 (m, 16H), 7.26-7.11 (m, 4H), 6.01-5.95 (m, 2H), 5.66 (d, J = 9.8 Hz, 1H), 5.12-5.05 (m, 1H), 5.03-4.64 (m, 7H), 4.60-4.57 (m, 1H), 4.49 (d, J = 10.8 Hz, 1H), 4.37 (dd, J = 10.6, 3.9 Hz, 1H), 4.29 (q, J = 10.2 Hz, 1H), 4.07 (dd, J = 12.5 Hz, 1H), 4.00 (t, J = 9.2 Hz, 1H), 3.83 - 3.80 (m) , 1H), 3.66 (t, J = 9.4 Hz, 1H), 3.61 (dd, J = 10.6, 1.7 Hz, 1H), 3.54 (dd, J = 9.7, 3.4 Hz, 1H), 3.45 (s, 3H) , 3.38 (s, 3H), 2.85 (dd, J = 12.7, 4.6 Hz, 1H), 2.11 (t, J = 12.7 Hz, 1H), 1.79 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) Δ170.4(C),168.0(C),166.4(C),166.0(C),16 4.0(C), 163.8(C), 150.1(CH), 149.5(CH), 148.0(C), 147.4(C), 139.1(C), 138.7(C), 138.3(C), 137.2(CH), 136.9 (CH), 133.4 (CH), 133.0 (CH), 129.9 (CH), 129.9 (CH), 129.8 (C), 129.4 (C), 128.6 (CH), 128.5 (CH), 128.4 (CH), 128.4 (CH), 128.2 (CH), 128.0 (CH), 128.0 (C), 127.7 (CH), 127.6 (CH), 127.6 (CH), 127.1 (CH), 127.0 (CH), 125.7 (CH), 125.5 (CH), 99.1 (C), 98.2 (CH), 82.1 (CH), 79.6 (CH), 75.8 (CH ₂ ), 74.8 (CH ₂ ), 73.4 (CH ₂ ), 72.6 (CH), 70.2 ( CH), 69.7 (CH), 69.7 (CH), 68.8 (CH), 63.7 (CH ₂ ), 62.6 (CH ₂ ), 55.2 (CH ₃ ), 52.5 (CH ₃ ), 49.7 (CH), 38.5 (CH) ₂ ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₆₆ H ₆₅ N ₃ O ₁₈ Na 1210.4155, Found 1210.4101.

Disaccharide 3e

Methyl 5-acetamido-4,7,8,9-tetra-O-benzhydryl-3,5-dideoxy-D-propanetriyl-D-galactose-non-2-ulopyranosylonate- (2→6)-Methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (Methyl 5-acetamido-4,7,8,9-tetra-O-benzoyl-3, 5-dideoxy-D-glycero-D-galacto-non-2-ulopyranosylonate-(2→6)-methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside)(3e)

CH ₂ Cl ₂ (7.0 ml) containing NIS (0.162 g, 0.72 mmol) and TfOH (0.048 g, 0.54 mmol) was added to the thiosialin 1e (0.300 g, 0.36 mmol) according to the general procedure. ), glucopyranoid receptor 2 (0.201 g, 0.43 mmol) and activated 3Å powder molecular sieve (0.467 g), reacted for 2 hours. Using ethyl acetate and n-hexane (1:2→1:1, volume ratio) as the extract, the pale yellow slurry residue obtained by purifying the tannin extract by flash column chromatography gave 0.398 g of white solid disaccharide. 3e , yield 90%: R _f = 0.25 (ethyl acetate: n-hexane = 1:2 (volume ratio)); FT-IR (neat) v _max 3395, 3065, 3031, 2935, 1724, 1602, 1527, 1452, 1364, 1315, 1270, 1215, 1171, 1100, 1071, 1025, 754, 713 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.14-8.12 (m, 2H), 7.99-7.97 (m, 2H) , 7.95-7.92 (m, 2H), 7.88-7.85 (m, 2H), 7.62-7.29 (m, 27H), 5.93 (t, J = 1.7 Hz, 1H), 5.90-5.87 (m, 1H), 5.60 -5.57 (m, 2H), 5.52-5.45 (m, 1H), 5.02-4.79 (m, 7H), 4.70-4.63 (m, 2H), 4.35 (q, J = 10.2 Hz, 1H), 4.09 - 4.00 (m, 2H), 3.96-3.94 (m, 1H), 3.78 (s, 3H), 3.72 (dd, J = 9.6, 3.6 Hz, 1H), 3.29 (s, 3H), 2.74 (dd, J = 12.9) , 5.0 Hz, 1H), 2.05 (dd, J = 12.9, 11.9 Hz, 1H), 1.77 (s, 3H); ¹³ C NMR (75 MHz, CDCl ₃ ) δ 170.1 (C), 167.4 (C), 166.5 (C), 166.4(C), 166.1(C), 165.5(C), 138.9(C), 138.6(C), 138.5(C), 133,3(CH), 133.3(CH), 133.2(CH) , 133.0 (CH), 130.0 (CH), 129.9 (CH), 129.8 (CH), 129.8 (CH), 129.5 (CH), 128.6 (CH), 128.5 (CH), 128.4 (CH), 128.4 (CH) , 128.3 (CH), 128.1 (CH), 128.0 (CH), 127.8 (CH), 127.7 (CH), 127.6 (CH), 98.3 (CH), 98.0 (CH), 82.2 (CH), 80.1 (CH), 75.8 (CH ₂ ), 75.2 (CH ₂ ) ,74.8(CH),73,2(CH ₂ ),72.2(CH),70.4(CH),69.9(CH),69.4(CH),63.5(CH ₂ ),62.5(CH ₂ ),55.0(CH _{3 )} ), 52.8 (CH ₃ ), 49.6 (CH), 38.0 (CH ₂ ), 23.2 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₆₈ H ₆₇ NO ₁₈ Na 1208.4250, Found 1208.4226.

The data in Table 1 demonstrates that the optimal saccharification reaction temperature of sialic acid donor 1d and acceptor 2 is -40 ° C, wherein the yield of product 3d is about 70%, and has excellent stereoselectivity (α only), accompanied by The rate was 27% of the product 4d. The sialic acid donor 1b also has a high alpha-stereoselectivity (α/β = 8:1) and a moderate yield of the disaccharide 3b (62%) with a yield of 24% of the product 4b. In contrast, sialic acid compounds 1a and 1c were not significant for disaccharide 3a (α/β = 1:1.2, yield 57%) and 3c (α/β = 1.3:1, yield 43%). The stereoselectivity of the compounds 4a and 4c was about 40% and 49%, respectively. The sialic acid donor 1e can be high yield (90%) and low alpha-stereoselectivity (α/β = 1:3.3) The disaccharide 3e was prepared.

1.3 Screening for optimal saccharification conditions

To analyze the optimal saccharification conditions for the coupling reaction of Example 1.2, the sialic acid donor 1d and receptor 2 were coupled according to a similar procedure as described in Examples 1 and 2 (except for adjusting the solvent and temperature); Products 3d and 4d. Table 2 summarizes the results of the analysis.

As shown in the results in Table 2, when the coupling temperature is raised from -40 ° C to -20 ° C, α-stereoselectivity (α and α/β = 5.3:1 only) and yield (70% and 24%) are reduced. ). In contrast, if the coupling temperature is further lowered to -60 ° C, the yield (69%) and α-stereoselectivity (α only) of the disaccharide 3d will be maintained except for a longer reaction time (about 5 hours). Similar results as when the temperature is -40 °C.

Coupling reaction in CH ₃ CN or CHCl ₃ instead of CH ₂ Cl ₂ still maintains excellent α-stereoselectivity (α only), but the yield of disaccharide 3d is not ideal (56% or 20%). When the solvent is replaced with toluene, the saccharification reaction does not occur at all.

Example 2 Screening for glycosidic receptors of the sialic acid donor of Example 1.

This example will utilize the optimal conditions identified in Example 1.3 to prepare different glycosyl acceptors and test their efficiency of coupling to the sialic acid donor 1d. Table 3 summarizes the representative results.

The data in Table 3 indicates that the sugar coupling of sialic acid donor 1d and primary alcohol 5a produced the highest yield (97%) of disaccharide 6a, which is a single alpha-stereoisomer. The primary alcohol 5b also has an excellent (98%) yield; however, its alpha-stereoselectivity is less than ideal (α/β = 2.8:1). The other two primary alcohols 5c and 5d were only capable of producing disaccharides 6c and 6d (68% and 73%, respectively) in a moderate yield, which had excellent α-stereoselectivity (α only). When the primary sugar 5e was used as the acceptor, the corresponding disaccharide 6e was not found, and only the olefinic by-product 4d (99%) was found.

Example 3 Synthesis of Hp-s1 by the sialic acid donor confirmed in Example 1 and optimal saccharification conditions

To confirm the applicability of the present disclosure, the natural ganglioside Hp-s1 was synthesized according to the procedure described in Scheme I and the method identified in Example 1 and a sialic acid donor. In general, the sialylation reaction of S-thiazolyl (STaz) receptor 8 with sialic acid donor 1d was carried out under the optimum conditions confirmed in Example 1, wherein NIS/TfOH was used as a promoter, and The coupling reaction was carried out in a powdery 3Å molecular sieve (MS-3Å) in CH ₂ Cl ₂ at -40 °C. The coupling reaction produces α-stereoisomer disaccharide 9 (yield 76%), followed by anhydrous CH ₂ Cl ₂ containing a promoter (eg, AgOTf) at 0 ° C, and a protected acetamidine plant. The sphingosine 11 was subjected to a coupling reaction, and only the ?-rotation isomer of Hp-s1 12 having a protective group was obtained in a yield of 25%. On the other hand, if the methyl sulfhydryl group is removed by treating the compound 9 with MeOH containing Cu(OAc) ₂ at -10 ° C, the prepared disaccharide 10 and the protective group of acetaminophen sphingosine 11 The saccharification reaction was carried out, and the yield was improved to 93% under the same conditions as those described above for the preparation of the disaccharide 9. The yield of Hp-s1 analog 13 was also as high as 87%, and it had excellent stereoselectivity (β only). The protected groups of Hp-s1 analogs 12 and 13 were then subjected to a deprotection reaction to prepare ganglioside Hp-s1 in yields of 75% and 89%, respectively.

2-thiazolinyl (methyl 5-acetamido-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O-methylindole-D- Propyltriyl-α-D-galacto-2-pyranose methyl ester)-(2→6)-2-O-acetamido-3,4-di-O-benzyl-β-D -Thiazolinyl (2-Thiazolinyl-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O-picoloyl-D-glycero-α-D-galacto- 2-nonulopyranoylonate )-(2→6)-2-O-acetyl-3,4-di-O-benzyl-β-D-glucopyranoside)(9)

According to the general procedure, CH ₂ Cl ₂ (12 ml) containing NIS (0.271 g, 1.20 mmol) and TfOH (0.080 ml, 0.90 mmol) was added to the thiosialin 1d (0.500 g, 0.60 mmol). ), glucopyranoid receptor 8 (0.360 g, 0.72 mmol) and activated 3Å powdered molecular sieve (0.600 g), reacted for 1 hour c using ethyl acetate and acetone/CH ₂ Cl ₂ (1/1, volume) The pale yellow slurry residue obtained by purifying the silica gel by flash column chromatography was obtained as a solvent to obtain 0.560 g of a colorless syrupy disaccharide 9 in a yield of 76%: R _f = 0.43 (acetone: CH _{2 )} Cl ₂ = 1:1 (volume ratio)); [α] ³⁰ _D + 72.1 (c 0.13, CHCl ₃ ); FT-IR (neat) v _max 3318, 2922, 2854, 1736, 1674, 1576, 1445, 1370 , 1280, 1237, 1122, 1078, 753, 710, 612 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.74 (d, J = 4.4 Hz, 1H), 8.67 (d, J = 4.4 Hz, 1H), 8.07 ( d, J = 7.8 Hz, 1H), 7.99-7.92 (m, 5H), 7.80 (td, J = 7.7, 1.4 Hz, 1H), 7.62 (td, J = 7.7, 1.6 Hz, 1H), 7.53 - 7.46 (m, 3H), 7.41-7.20 (m, 16H), 6.05-6.04 (m, 2H), 5.72 (d, J = 9.6 Hz, 1H), 5.27 (d, J = 10.4 Hz, 1H), 5.14 ( Ddd, J = 12.7, 8.8, 4.6 Hz, 1H), 5.08 (dd, J = 10.4, 9.2 Hz, 1H), 4.97 - 4.29 (m, 9H), 4.27 - 4.09 (m, 2H), 3.83 - 3.69 ( m, 3H), 3.60 (dd, J=9.6, 2.2 Hz, 1H), 3.49 (s, 3H), 3.32 (t, J = 8.1 Hz, 2H), 2.87 (dd, J = 12.7, 4.6 Hz, 1H), 2.09 (t , J = 12.7 Hz, 1H), 1.95 (s, 3H), 1.79 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 170.4 (C), 169.5 (C), 167.6 (C), 166.1 (C), 165.8(C), 163.8(C), 163.7(C), 163.5(C), 149.9(CH), 149.5(CH), 147.7(C), 147.1(C), 138.0(C), 138.0 (C), 137.0 (CH), 136.9 (CH), 133.2 (CH), 132.8 (CH), 129.6 (CH), 129.6 (C), 129.3 (C), 128.3 (CH), 128.3 (CH), 128.2 (CH), 127.9 (CH), 127.7 (CH), 127.6 (CH), 126.9 (CH), 126.9 (CH), 125.5 (CH), 125.4 (CH), 99.1 (C), 84.0 (CH), 83.1 (CH), 78.4 (CH), 77.0 (CH), 75.1 (CH ₂ ), 74.8 (CH ₂ ), 72.7 (CH), 71.2 (CH), 70.5 (CH), 70.1 (CH), 69.1 (CH) , 64.0 (CH ₂ ), 63.4 (CH ₂ ), 62.8 (CH ₂ ), 52.5 (CH ₃ ), 49.3 (CH), 41.8 (CH ₂ ), 38.1 (CH ₂ ), 34.9 (CH ₂ ), 26.9 ( CH ₂ ), 24.8 (CH ₂ ), 23.0 (CH ₃ ), 20.8 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₆₃ H ₆₂ N ₄ O ₁₈ S ₂ Na 1249.3394, Found 1249.3369.

(Methyl 5-acetamido-4,9-di-O-benzhydryl-3,5-dideoxy-7,8-di-O-methylindole-D-propyltriyl-α -D-galacto-2-pyranose methyl ester)-(2→6)-2-O-acetamido-3,4-di-O-benzyl-β-D-glucopyranoside -(1→1)-(2S,3S,4R)-3,4-O-o-isopropylidene-2-octadecylaminooctadecane-1,3,4-triol ((Methyl 5- Acetamido-4,9-di-O-benzoyl-3,5-dideoxy-7,8-di-O-picoloyl-D-glycero-α-D-galacto-2-nonulopyranoylonate)-(2→6)-2 -O-acetyl-3,4-di-O-benzyl-β-D-glucopyranosyl-(1→1)-(2S,3S,4R)-3,4-O-isopropylidenyl- 2-octadecanoylaminooctadecane-1,3,4-triol)(12)

The sialic acid donor 9 (0.110 g, 0.09 mmol) dissolved in anhydrous CH ₂ Cl ₂ (0.9 mL), the acceptor 11 (0.067 g, 0.11 mmol) and the activated 3 Å were stirred in a nitrogen atmosphere. Powdered molecular sieves (0.124 g) were used to remove residual moisture. After cooling the reaction mixture to 0 ° C, AgOTf (0.500 g, 0.27 mmol) was added. Stirring was continued at this temperature until TLC showed complete reaction; after triethylamine was added to the reaction mixture, it was filtered through a short pad of diatomaceous earth. The filtrate was washed with ice-saturated Na ₂ S ₂ O ₃ solution and brine, dried over MgSO ₄ and filtered. Using acetone and CH ₂ Cl ₂ (1/2, by volume) as the extract, the pale yellow slurry residue obtained by purifying the tannin extract by flash column chromatography gave 0.038 g of colorless paste-like disaccharide 12 Rate 25%: R _f =0.30 (ethyl acetate); [α] ³⁰ _D +45.5 (c 0.21, CHCl ₃ ); FT-IR (neat) v _max 3306, 3065, 2925, 2855, 1736, 1670, 1544 , 1458, 1371, 1279, 1120, 753, 709, 614 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.75 (d, J = 4.0 Hz, 1H), 8.67 (d, J = 4.0 Hz, 1H), 8.07 (d, J = 7.8 Hz, 1H), 7.98-7.91 (m, 5H), 7.80 (td, J = 7.8, 1.7 Hz, 1H), 7.63 (td, J = 7.8, 1.7 Hz, 1H), 7.53 7.47 (m, 3H), 7.42-7.19 (m, 15H), 6.10-6.03 (m, 2H), 5.85 (d, J = 8.2 Hz, 1H), 5.70 (d, J = 9.6 Hz, 1H), 5.15 -5.09 (m, 1H), 4.97-4.62 (m, 6H), 4.50 (dd, J = 10.9, 1.4 Hz, 1H), 4.36-4.28 (m, 4H), 4.12-4.03 (m, 3H), 3.96 (dd, J = 10.0, 3.6 Hz, 1H), 3.77-3.72 (m, 2H), 3.64 (t, J = 9.1 Hz, 1H), 3.57 (dd, J = 10.0, 1.8 Hz, 1H), 3.49 ( s,3H), 2.84 (dd, J=12.7, 4.4 Hz, 1H), 2.14-2.11 (m, 3H), 1.95 (s, 3H), 1.80 (s, 3H), 1.58-1.47 (m, 4H) , 1.35 (s, 3H), 1.25 (s, 55H), 0.88 (t, J = 6.8 Hz, 6H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 172.7 (C), 170.3 (C), 169.8 ( C), 167.9(C), 166.5(C), 166.1(C), 164.1(C), 164.0(C), 150.2(CH), 149.8(CH),1 48.1(C), 148.1(C), 147.4(C), 138.4(C), 138.2(C), 137.1(CH), 137.0(CH), 133.5(CH), 133.1(CH), 130.0(CH), 129.9(CH),129.8(C),129.4(C),128.6(CH),128.6(CH),128.5(CH),128.4(CH),128.2(CH),128.0(CH),127.9(CH), 127.8(CH),127.1(CH),127.0(CH),125.8(CH),125.6(CH),107.9(C),101.3(CH),99.3(C),82.9(CH),77.9(CH), 77.6(CH),76.3(CH),75.2(CH ₂ ),75.0(CH ₂ ),74.3(CH),73.5(CH),72.7(CH),69.9(CH),69.8(CH),69.2(CH) ₂ ), 69.1 (CH), 63.7 (CH ₂ ), 63.0 (CH ₂ ), 52.7 (CH ₃ ), 50.0 (CH), 48.2 (CH), 38.5 (CH ₂ ), 36.9 (CH ₂ ), 32.1 ( CH ₂ ), 29.9 (CH ₂ ), 29.8 (CH ₂ ), 29.8 (CH ₂ ), 29.7 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH _{2 )} ), 29.2 (CH ₂ ), 28.1 (CH ₃ ), 26.7 (CH ₂ ), 25.8 (CH ₃ ), 25.8 (CH ₂ ), 23.3 (CH ₃ ), 22.8 (CH ₂ ), 21.2 (CH ₃ ), 14.3 (CH ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₉₉ H ₁₃₄ N ₄ O ₂₂ Na 1753.9382, Found 1753.9383.

The title compound Hp-s1 was synthesized . The isopropylidene acetal 12 (0.050 g, 28.90 micromoles) was dissolved in an 80% AcOH solution (10 ml) at 0 ° C, and the mixture was continuously stirred at 85 ° C for 4 hours. The reaction mixture was co-evaporated with toluene. Without further purification, after the obtained colorless syrupy diol was dissolved in MeOH (10 mL) at room temperature, 20% Pd(OH) _{2 /} C (0.003 g) was added. The reaction mixture was continuously stirred at room temperature under a hydrogen (50 psi) atmosphere for 1 hour. After removing Pd(OH) ₂ /C with a short pad of SiO ₂ /celite, the filtrate was washed with MeOH. The filtrate was then concentrated in vacuo at 0 °C. Without further purification, the obtained colorless syrupy was dissolved in anhydrous MeOH (0.27 mL) and then EtOAc (1 mg, 0.027 m. After stirring at room temperature for 3 hours, H ₂ O (0.15 mL) was added. After completion of the saponification reaction, the solution was neutralized with Dowex 50w X 8 [H ⁺ ]. The resin was filtered and washed with MeOH / CH ₂ Cl ₂ (3:1, by volume). The filtrate was concentrated under reduced pressure to give a white solid residue. After recrystallization of 22 mg of Hp-s1 (MeOH / CH ₂ Cl ₂ /EtOAc) afforded a white solid compound,yield: 75% yield: _Rf = 0.23 (MeOH: CH ₂ Cl ₂ = 1:1 Volume ratio)); [α] ²⁴ _D -1.3 (c 0.20, MeOH: CHCl ₃ = 3:1); FT-IR (neat) v _max 3373, 2921, 2853, 1639, 1552, 1481, 1372, 1314, 1204, 1116, 1080, 1040, 760 cm ^-1 ; ¹ H NMR (400 MHz, CD ₃ OD: CDCl ₃ = 3:1) δ 4.26 (d, J = 7.7 Hz, 1H), 4.17 - 4.05 (m, 3H) , 3.86-3.82 (m, 2H), 3.77-3.61 (m, 6H), 3.59-3.51 (m, 3H), 3.45-3.32 (m, 3H), 3.21 (t, J = 8.4 Hz, 1H), 2.74 (dd, J = 12.3, 4.2 Hz, 1H), 2.21 (t, J = 7.4 Hz, 2H), 2.01 (s, 3H), 1.76 (t, J = 12.3 Hz, 1H), 1.61-1.39 (m, 4H), 1.28 (s, 52H), 0.89 (t, J = 6.8 Hz, 6H); ¹³ C NMR (100 MHz, CD ₃ OD: CDCl ₃ = 3:1) δ 174.6 (C), 174.2 (C), 170.5(C), 103.4(CH), 98.2(C), 76.1(CH), 74.9(CH), 73.6(CH), 73.5(CH), 73.4(CH), 71.8(CH), 71.1(CH), 69.3(CH),69.1(CH ₂ ),68.7(CH),67.3(CH),63.2(CH ₂ ),62.3(CH ₂ ), 52.5(CH),50.4(CH),40.2(CH ₂ ),36.2 (CH ₂ ), 31.8 (CH ₂ ), 31.8 (CH ₂ ), 31.1 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH) ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.5 (CH ₂ ), 29.4 (CH ₂ ), 29.4 (CH ₂ ), 29.2 (CH) ₂ ),29.2 (CH ₂ ), 25.9 (CH ₂ ), 25.8 (CH ₂ ), 22.5 (CH ₂ ), 21.8 (CH ₃ ), 13.6 (CH ₃ ); HRMS-ESI [MH] ^- Calcd for C ₅₃ H ₉₉ N ₂ O ₁₇ 1035.6949, Found 1035.6939.

Although the embodiments of the present invention are disclosed in the above embodiments, the present invention is not intended to limit the invention, and the present invention may be practiced without departing from the spirit and scope of the invention. Various changes and modifications may be made thereto, and the scope of the invention is defined by the scope of the appended claims.

Claims (9)

a sialic acid donor for synthesizing gangliosides having the structure of formula (I), Wherein R ₁ and R ₂ are each a benzepyl group, a toluenesulfonyl group, a trimethylethenyl group or an ethyl fluorenyl group which may be optionally substituted by a halogen; and R ₃ is an ethyl fluorenyl group or a -(O)CCH group; ₂ OH, wherein Pico is picoloyl. The sialic acid donor according to claim 1, wherein the sialic acid donor of the formula (I) is any one of the following: The sialic acid donor according to claim 1, wherein in the sialic acid donor of the formula (I), R ₁ and R ₂ are each a benzamidine group, and R ₃ is an ethyl hydrazino group. A method for the synthesis of a neuraminidase, comprising: (a) having N - iodosuccinimide (PEI) (N -iodosuccinimide, NIS) and trifluoromethanesulfonic acid (trifluoromethanesulfonic acid, TfOH) under suitable conditions of the a sialic acid donor coupled to a glycosidic receptor having a primary hydroxyl group; and (b) an isolated sialic acid having an alpha-glucosidic linkage; wherein the sialic acid donor has the structure of formula (I) , Wherein R ₁ and R ₂ are respectively benzamyl, toluenesulfonyl, trimethylethenyl or ethyl hydrazino which may be optionally substituted by halogen; and R ₃ is ethenyl or -(O)CCH ₂ OH, wherein Pico is picoloyl. The method of claim 4, wherein the step (a) is a group consisting of CH ₃ CN, CH ₃ Cl and CH ₂ Cl ₂ at a temperature between -20 ° C and -60 ° C. Coupling in the solvent. The method of claim 5, wherein the step (a) is carried out in CH ₂ Cl ₂ at a temperature of -40 ° C. The method of claim 4, wherein the step (a) is carried out by a powder molecular sieve. The method of claim 4, wherein the sialic acid donor of formula (I) is any one of the following: The method of claim 4, wherein in the sialic acid donor of formula (I), R ₁ and R ₂ are each a benzamidine group, and R ₃ is an ethenyl group.