Synthesis of sialyl-α-(2→3)-neolactotetraose derivatives modified at C-2 of the N-acetylglucosamine residue: Probes for investigation of acceptor specificity of human α-1,3-fucosyltransferases, Fuc-TVII and Fuc-TVI

DOI: 10.1081/CAR-120014902

Source and publish data:

Journal of Carbohydrate Chemistry p. 385 - 409 (2002)

Update date:2022-08-04

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Authors:

Fukunaga, Kyoko

Ikami, Nagisa

Ishida, Hideharu

Kiso, Makoto

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Article abstract of DOI:10.1081/CAR-120014902

A variety of sialyl-α-(2→3)-neolactotetraose (IV³NeuAcnLcOse₄ or IV³NeuGcnLcOse₄) derivatives (23, 31-37, 58-60) modified at C-2 of the GlcNAc residue have been synthesized. The phthalimido group at C-2 of GlcNAc in 2-(trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-(1→3)- (2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl -β-D-glucopyranoside (5) was systematically converted to a series of acylamino groups, to give the per-O-benzylated trisaccharide acceptors (6-11). On the other hand, modification of the hydroxyl group at C-2 of the terminal Glc residue in 2-(trimethylsilyl)ethyl (4,6-O-benzylidene-β-D-glucopyranosyl)-(1→3)-(2,4,6-tri-O-benzyl- β-D-galactopyr-anosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D- glucopyranoside (42) gave three different kinds of trisaccharide acceptors containing D-glucose (49), N-acetyl-D-mannosamine (50), and D-mannose (51) instead of the GlcNAc residue. Totally ten trisaccharide acceptors (5-11 and 49-51) were each coupled with sialyl-α-(2→3)-galactose donor 12 to afford the corresponding pentasaccharides (14-21 and 52-54) in good yields, respectively, which were then transformed into the target compounds. Acceptor specificity of the synthetic sialyl-α-(2→3)-neolactotetraose probes for the human α-(1→3)-fucosyltransferases, Fuc-TVII and Fuc-TVI, was examined.

Full text of DOI:10.1081/CAR-120014902

Journal of Carbohydrate Chemistry

ISSN: 0732-8303 (Print) 1532-2327 (Online) Journal homepage: http://www.tandfonline.com/loi/lcar20

SYNTHESIS OF SIALYL-α-(2→3)-

NEOLACTOTETRAOSE DERIVATIVES MODIFIED

AT C-2 OF THE N-ACETYLGLUCOSAMINE

RESIDUE: PROBES FOR INVESTIGATION OF

ACCEPTOR SPECIFICITY OF HUMAN α-1,3-

FUCOSYLTRANSFERASES, FUC-TVII, AND FUC-TVI ^*

Kyoko Fukunaga† , Nagisa Ikami , Hideharu Ishida & Makoto Kiso

To cite this article: Kyoko Fukunaga† , Nagisa Ikami , Hideharu Ishida & Makoto Kiso (2002)

SYNTHESIS OF SIALYL-α-(2→3)-NEOLACTOTETRAOSE DERIVATIVES MODIFIED AT C-2 OF

THE N-ACETYLGLUCOSAMINE RESIDUE: PROBES FOR INVESTIGATION OF ACCEPTOR

SPECIFICITY OF HUMAN α-1,3-FUCOSYLTRANSFERASES, FUC-TVII, AND FUC-TVI ^*, Journal

of Carbohydrate Chemistry, 21:5, 385-409

To link to this article: http://dx.doi.org/10.1081/CAR-120014902

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JOURNAL OF CARBOHYDRATE CHEMISTRY

Vol. 21, No. 5, pp. 385–409, 2002

SYNTHESIS OF SIALYL-a-(2 3)-

NEOLACTOTETRAOSE DERIVATIVES MODIFIED

AT C-2 OF THE N-ACETYLGLUCOSAMINE

RESIDUE: PROBES FOR INVESTIGATION OF

ACCEPTOR SPECIFICITY OF HUMAN a-1,3-

FUCOSYLTRANSFERASES, FUC-TVII AND FUC-TVI^*

Kyoko Fukunaga, Nagisa Ikami, Hideharu Ishida, and Makoto Kiso

Department of Applied Bioorganic Chemistry, Gifu University,

Gifu 501-1193, Japan

ABSTRACT

A variety of sialyl-a-(2!3)-neolactotetraose (IV³NeuAcnLcOse₄or

IV³NeuGcnLcOse₄) derivatives (23, 31–37, 58–60) modified at C-2 of the

GlcNAc residue have been synthesized. The phthalimido group at C-2 of

GlcNAc in 2-(trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-phthalimido-

b-^D-glucopyranosyl)-(1!3)-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-

(1!4)-2,3,6-tri-O-benzyl-b-^D-glucopyranoside (5) was systematically con-

verted to a series of acylamino groups, to give the per-O-benzylated tri-

saccharide acceptors (6–11). On the other hand, modification of the hydroxyl

group at C-2 of the terminal Glc residue in 2-(trimethylsilyl)ethyl (4,6-O-

benzylidene-b-^D-glucopyranosyl)-(1!3)-(2,4,6-tri-O-benzyl-b-D-galactopyr-

anosyl)-(1!4)-2,3,6-tri-O-benzyl-b-^D-glucopyranoside (42) gave three dif-

Synthetic studies on sialoglycoconjugates, Part 125. For Part 124, see Otsubo, N.; Ishida, H.; Kiso,

M. Chemical approach to selectin ligands: total synthesis of O-glycan on GlyCAM-1. Aust. J.

Chem.-Int. J. Chem. Sci., 2002, 55, 105–112.

Current address: Basic Research Laboratory, Kanebo Ltd., Kotobuki-cho, Odawara-shi,

Kanagawa, Japan.

Corresponding authors. E-mails: ishida@cc.gifu-u.ac.jp; kiso@cc.gifu-u.ac.jp

385

DOI: 10.1081/CAR-120014902

0732-8303 (Print); 1532-2327 (Online)

www.dekker.com

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FUKUNAGA ET AL.

ferent kinds of trisaccharide acceptors containing D-glucose (49), N-acetyl-D-

mannosamine (50), and ^D-mannose (51) instead of the GlcNAc residue.

Totally ten trisaccharide acceptors (5–11 and 49–51) were each coupled with

sialyl-a-(2!3)-galactose donor 12 to afford the corresponding pentasacchar-

ides (14–21 and 52–54) in good yields, respectively, which were then

transformed into the target compounds. Acceptor specificity of the synthetic

sialyl-a-(2!3)-neolactotetraose probes for the human a-(1!3)-fucosyltrans-

ferases, Fuc-TVII and Fuc-TVI, was examined.

Key Words: Selectin; Sialyl Lewis x; Sialyl paragloboside; Fucosyl

transferase

INTRODUCTION

The sialyl Lewis x (sLe^x) determinant, NeuAc-a-(2!3)-Gal-b-(1!4)-[Fuc-a-

(1!3)]-GlcNAc, has been identified^[1,2]as a common carbohydrate ligand for E-, P-,

and L-selectin, a family of cell adhesion molecules involved in leukocyte recruitment to

sites of inflammation, thrombosis, and in lymphocyte binding to high endothelial ve-

nules (HEV) of lymph nodes during lymphocyte recirculation. Recent studies have

demonstrated that Fuc-TVII, a member of a-1,3-fucosyltransferase (Fuc-T) family, is

implicated in the biosynthesis of selectin ligands as a key enzyme.^[3–6]Sialyl-a-(2!3)-

neolactotetraose is a biosynthetic precursor which undergoes enzymatic fucosylation at

C-3 of the N-acetylglucosamine (GlcNAc) residue to give sLe^xhexasaccharide. We

have recently reported the synthesis of a series of sialyl-a-(2!3)-neolactotetraose

derivatives^[7,8]containing modified sialic acids and the sulfated Gal/GlcNAc residues to

investigate^[9]the acceptor specificity of human a-1,3-fucosyltransferases, Fuc-TVII and

Fuc-TVI which show activity toward both a-2,3-sialylated and nonsialylated type-2

oligosaccharides. In the continuing study to demonstrate the detailed substrate speci-

ficity of Fuc-TVII and Fuc-TVI, we describe herein the synthesis of a variety of novel

sialyl-a-(2!3)-neolactotetraose derivatives modified at C-2 of the GlcNAc residue.

RESULTS AND DISCUSSION

The key synthetic intermediate 2-(trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-

2-phthalimido-b-^D-glucopyranosyl)-(1!3)-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-

(1!4)-2,3,6-tri-O-benzyl-b-^D-glucopyranoside (5) was prepared from compound 1^[10]

in four steps, via removal of the acetyl groups, formation of the benzylidene acetal,

benzylation, and reductive opening of the benzylidene ring. After cleavage of the

phthalimido group in 5 with hydrazine monohydrate, the resulting amine derivative was

treated with carbobenzoxy chloride, benzoic anhydride, butanoic anhydride, octanoic

anhydride, lauric acid, and palmitic acid, respectively, in the presence of 1-(3-dimeth-

ylaminopropyl)-3-ethylcarbodiimide hydrochloride (WSC), to give a series of N-acyl-

glucosamine-containing trisaccharide acceptors 6–11 (Scheme 1). Glycosylation of

5–11 with methyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-^D-glycero-

a-^D-galacto-2-nonulopyranosylonate)-(2!3)-2,4,6-tri-O-benzoyl-1-thio-b-D-galactopy-

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Scheme 1. Synthesis of the title compounds (1).

ranoside 12^[10]in dichloromethane in the presence of dimethyl(methylthio)sulfonium

triflate (DMTST)^[11,12]and powdered 4A molecular sieves (MS4A) gave the desired

pentasaccharide derivatives 14–20 in 75–85% yields, respectively (Scheme 1).

In the same way, glycosylation of 10 with N-glycolylneuraminyl-a-(2!3)-

galactose donor 13^[7]in the presence of trimethylsilyl trifluoromethanesulfonate

(TMSOTf) gave another pentasaccharide derivative 21 in 81% yield.

Removal of the O-acetyl and O-benzoyl groups in 15 with sodium methoxide in

methanol, and subsequent saponification of the methyl ester group afforded 22, which

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FUKUNAGA ET AL.

was then hydrogenolyzed over Pd(OH)₂in acetic acid to give the 2-amino derivative 23

(GSC-290). On the other hand, hydrogenolytic removal of the benzyl groups in 14 and

16–21 over Pd(OH)₂, and subsequent treatment with acetic anhydride in pyridine gave

the per-O-acylated pentasaccharides 24–30, which were converted, by removal of the

O-acyl groups and saponification of the methyl ester group, to a series of the GlcNAc-

modified (N-acyl) sialyl-a-(2!3)-neolactotetraose derivatives 31–37 (Scheme 2).

For the synthesis of another three IV³NeuAcnLcOse₄probes (58–60) modified at

C-2 of the GlcNAc residue, we employed 2-(trimethylsilyl)ethyl (4,6-O-benzylidene-b-

D-glucopyranosyl)-(1!3)-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-(1!4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside 42 as the common intermediate (Scheme 3).

Coupling of 38 and 39^[10]according to Koenigs-Knorr conditions in the presence

of silver perchlorate and silver carbonate gave the expected b-glycoside 40 in 60%

yield (Scheme 4). O-Deacetylation of 40 and the formation of benzylidene acetal in 41

gave 42. 2,3-Di-O-benzylation of 42, and reductive ring opening of the benzylidene

acetal in 43 gave the desired trisaccharide acceptor 49. In comparison, regioselective

Scheme 2. Synthesis of the title compounds (2).

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Scheme 3. Synthesis of the title compounds (3).

benzylation of 42 using phase transfer catalysis^[13]afforded the 3-O-benzyl derivative

44 in 80% yield accompanied by the 2-O-benzyl derivative (11%). After introduction

of the trifluoromethanesulfonyl (Tf) group of 44, S_N2 type displacement using sodium

azide or cesium acetate as a nucleophile was achieved to give the C-2 epimerized azido

(46) and OAc (48) derivatives. Treatment of 46 with triphenylphosphine and water, and

subsequent acetylation gave the desired trisaccharide (47) containing N-acetyl-^D-

mannosamine. Reductive ring opening of the benzylidene acetal in 47 and 48 gave the

manno-type trisaccharide acceptors 50 and 51 (Scheme 3).

Glycosylation of 49–51 with 12 in the presence of DMTST afforded the desired

pentasaccharide derivatives 52 (73%), 53 (80%), and 54 (84%), respectively, which

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FUKUNAGA ET AL.

Scheme 4. Synthesis of the title compounds (4).

were converted, by catalytic hydrogenolysis over Pd(OH)₂followed by O-acetylation to

give the per–O-acylated pentasaccharides 55–57. Finally, complete O-deacylation and

saponification of the methyl ester group in 55–57 afforded the novel Glc (58),

ManNAc (59) and Man (60) derivatives of sialyl-a-(2!3)-neolactotetraose.

The synthetic sialyl-a-(2!3)-neolactotetraose probes (23, 31–37, and 58–60)

were subjected to a competitive enzyme assay^[9]using human Fuc-TVII and Fuc-TVI

(Scheme 5, Table 1). Substitution of the acetamido group at C-2 of GlcNAc with the

lauroylamino group (35;GSC-302) significantly increased the relative competition

(141.8%) for Fuc-TVI, while the degree for Fuc-TVII was 73.8%. It is of interest that

the affinities of the compounds are dependent on the length of fatty acids introduced

(33–35; GSC-291, 292, 302). In contrast, modifications of the acetamido group both

at C-5 of N-acetylneuraminic acid and at C-2 of GlcNAc (37;GSC-351) showed almost

comparable competition activity for either Fuc-TVII (102.4%) or Fuc-TVI (103.5%).

In addition, modification of the acetamido group at C-2 with a bulky N-acyl group,

such as phthalimido (31;GSC-294) or benzoylamino group (32;GSC-293) decreased

the activity, significantly. Replacement of the acetamido group by the free amino

(23;GSC-290) and hydroxyl group (58;GSC-323), as well as epimerization of the

configuration at C-2 of GlcNAc (59;GSC-347, 60;GSC-348) abolished the activity for

both Fuc-TVII and Fuc-TVI. Therefore, the acylamino portion at C-2 of GlcNAc is

essential for acceptor recognition and may be designated as a key functional group for

both enzymes.

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Scheme 5. Principle of competitive enzyme assay.

Table 1. Relative Competition of 23, 31–37, and 58–60

Relative Competition (%)^a

Compound

Fuc-TVII

Fuc-TVI

(GSC-253)

100

ND^b

19.5

20.5

28.4

44.6

73.8

9.2

100

23 (GSC-290)

31 (GSC-294)

32 (GSC-293)

33 (GSC-291)

34 (GSC-292)

35 (GSC-302)

36 (GSC-303)

37 (GSC-351)

58 (GSC-323)

59 (GSC-347)

60 (GSC-348)

35.3

40.9

53.1

104.6

141.8

25.6

103.5

102.4

^aRelative competition was determined with the competition of GSC-253,

in the presence of 25 mM pyridylaminated acceptor.^[9]

^bND, Not detected ( < 5.0%).

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EXPERIMENTAL

General procedures. Optical rotations were determined with a Union PM-201

polarimeter at 25°C, and IR spectra were recorded with a Jasco IRA-100 spectro-

photometer. ¹H NMR spectra were recorded at 400 or 200 MHz with a Varian Inova 400

or Varian Gemini-2000 spectrometer using deuterated solvents (CDCl₃, CD₃OD) with

TMS as the internal standard. TLC was performed on Silica Gel 60 (E. Merck), and

column chromatography on silica gel (Fuji Silysia Co., 300 mesh) was accomplished

with the solvent systems (v/v) specified. Concentrations were conducted in vacuo.

2-(Trimethylsilyl)ethyl (2-deoxy-2-phthalimido-b-^D-glucopyranosyl)-(1 3)-

(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glucopyra-

noside (2). To a solution of 1 (6.33 g, 4.5 mmol) in MeOH (80 mL) was added a

catalytic amount of NaOMe, and the mixture was stirred for 2 h at room temperature

and then neutralized with Amberlite IR-120 (H ⁺) resin. The resin was filtered off and

washed with MeOH, and the combined filtrate and washings were concentrated. Col-

umn chromatography (AcOEt:hexane= 1:1) of the residue on silica gel gave 2 (5.08 g,

88%) as a syrup; [a]_D-19.8° (c 0.98, CHCl₃); IR (film) 3550, 2950, 1800, 1750, 860,

840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.98 (m, 2H, Me₃SiCH₂CH₂), 5.42 (d, 1H, J =8.2

Hz, H-1c), 6.92–7.42 (m, 34H, 6Ph and NPhth).

Anal. Calcd for C₇₃H₈₃NO₁₇Si: C, 68.79; H, 6.56; N, 1.10. Found: C, 68.60; H,

6.33; N, 0.94.

2-(Trimethylsilyl)ethyl (4,6-O-benzylidene-2-deoxy-2-phthalimido-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (3). To a solution of 2 (5.0 g, 4.0 mmol) in acetonitrile

(30 mL) were added Drierite (2.5 g), benzaldehyde dimethyl acetal (1.2 mL, 8.0

mmol), and catalytic amount of p-toluenesulfonic acid, and the reaction mixture was

stirred for 2 h at room temperature. The mixture was neutralized with Na₂CO₃, and the

solids were filtered off and washed with CH₂Cl₂. The combined filtrate and washings

was concentrated. Column chromatography (AcOEt:hexane =1:4) of the residue on

silica gel gave 3 (4.8 g, 88%) as an amorphous mass; [a]_Dꢀ 21.9° (c 4.1, CH₂Cl₂);

IR(film) 3500, 2950, 1800, 1750, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.98 (m,

2H, Me₃SiCH₂CH₂), 5.46 (d, 1H, J= 8.4 Hz, H-1c), 5.56 (s, 1H, PhCH), 6.90–7.52 (m,

39H, 7Ph and NPhth).

Anal. Calcd for C₈₀H₈₇NO₁₇Si: C, 70.52; H, 6.44; N, 1.03. Found: C, 70.45; H,

6.42; N, 0.96.

2-(Trimethylsilyl)ethyl (3-O-benzyl-4,6-O-benzylidene-2-deoxy-2-phthalimido-

b-^D-glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-(1 4)-2,3,6-

tri-O-benzyl-b-^D-glucopyranoside (4). To a solution of 3 (4.8 g, 3.5 mmol) in DMF

(20 mL) was added 60% NaH in oil (0.17 g, 4.2 mmol) at 0°C. After 30 min, BnBr

(0.62 mL, 5.3 mmol) was added to the mixture, which was stirred for 2 h at room

temperature. The mixture was extracted with AcOEt and washed with water. The

organic layer was dried over Na₂SO₄and concentrated. Column chromatography

(AcOEt:hexane =1:6) of the residue on silica gel gave 4 (4.2 g, 82%) as a syrup; [a]_D–

4.4° (c 0.5, CH₂Cl₂); IR (film) 2950, 1800, 1750, 860, 840, 700 cm ^{ꢀ 1}

;

¹H NMR

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(CDCl₃) d 0.99 (m, 2H, Me₃SiCH₂CH₂), 5.50 (d, 1H, J=8.3 Hz, H-1c), 5.63 (s, 1H,

PhCH), 6.83–7.56 (m, 44H, 8Ph and NPhth).

Anal. Calcd for C₈₇H₉₃NO₁₇Si: C, 71.93; H, 6.45; N, 0.96. Found: C, 71.83; H,

6.31; N, 0.83.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-phthalimido-b-^D-glucopy-

ranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-ben-

zyl-b-^D-glucopyranoside (5). To a solution of 4 (580 mg, 0.4 mmol) in THF (5 mL)

was added MS3A (300 mg), and the reaction mixture was stirred for 3 h at room

temperature. Sodium cyanoborohydride (380 mg, 6.0 mmol) was added to the mixture,

and then hydrogen chloride in diethyl ether was added dropwise to the stirred mixture,

with stirring being continued for 30 min. The mixture was neutralized with Et₃N and

diluted with CH₂Cl₂and water. The solids were removed through celite, and the filtrate

was washed with water. The organic layer was dried over Na₂SO₄and concentrated.

Column chromatography (AcOEt:hexane=1:4) of the residue on silica gel gave 5 (510

mg, 88%) as a syrup; [a]_Dꢀ 8.1° (c 7.0, CH₂Cl₂); IR(film) 3500, 2950, 1800, 1750,

860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.06 (m, 2H, Me₃SiCH₂CH₂), 5.43 (d, 1H,

J= 7.9 Hz, H-1c), 7.00–7.74 (m, 44H, 8Ph and NPhth).

Anal. Calcd for C₈₇H₉₅NO₁₇Si: C, 71.83; H, 6.58; N, 0.96. Found: C, 71.72; H,

6.58; N, 0.73.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-carbobenzyloxyamino-2-deoxy-b-^D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (6). To a solution of 5 (260 mg, 0.18 mmol) in eth-

anol (10 mL) was added hydrazine monohydrate (0.4 mL, 7.2 mmol), and the reaction

mixture was stirred for 36 h under reflux. After completion of the reaction, the mixture

was concentrated, and the residue was treated with carbobenzoxy chloride (30 mL, 0.2

mmol) in acetone (8 mL) and sat Na₂CO₃(1 mL) for 12 h at room temperature. The

mixture was concentrated and the residue was taken up in CH₂Cl₂, and washed with

water, dried (Na₂SO₄), and concentrated. Column chromatography (AcOEt:hexane=

1:3) of the residue on silica gel gave 6 (248 mg, 95%) as an amorphous mass;

[a]_Dꢀ 9.0° (c 2.5, CH₂Cl₂); IR (KBr) 3400, 2900, 1720, 1606, 1587, 860, 840,

700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.01 (m, 2H, Me₃SiCH₂CH₂), 4.84 (d, 1H, J=9.2

Hz, NH), 5.08(d, 1H, J =7.69 Hz, H-1c), 7.12–7.37(m, 45H, 9Ph).

Anal. Calcd for C₈₃H₉₇NO₁₇Si: C, 70.81; H, 6.70; N, 0.96. Found: C, 70.80; H,

6.60; N, 0.67.

2-(Trimethylsilyl)ethyl (2-benzoylamino-3,6-di-O-benzyl-2-deoxy-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (7). To a solution of 5 (780 mg, 0.54 mmol) in ethanol

(20 mL) was added hydrazine monohydrate (0.6 mL, 13.0 mmol) and then the reaction

mixture was refluxed for 48 h as described for 6. The mixture was concentrated, and

the residue was treated with benzoic anhydride (0.5 g, 1.1 mmol) in MeOH (10 mL) for

12 h at room temperature. After completion of the reaction, the mixture was concen-

trated, and the residue was taken up in CH₂Cl₂, washed with 2 M HCl, sat Na₂CO₃and

water, dried (Na₂SO₄), and concentrated. Column chromatography (CH₂Cl₂:MeOH =

100:1) of the residue on silica gel gave 7 (522 mg, 68%) as an amorphous mass;

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[a]_Dꢀ 16.1° (c 2.8, CH₂Cl₂); IR (film) 3400, 2950, 1650, 1550, 860, 840, 700 cm^ꢀ1; ¹H

NMR (CDCl₃) d 1.00 (m, 2H, Me₃SiCH₂CH₂), 5.79 (d, 1H, J=8.33 Hz, NH), 7.02–7.42

(m, 45H, 9Ph).

Anal. Calcd for C₈₆H₉₇NO₁₆Si: C, 72.29; H, 6.84; N, 0.98. Found: C, 72.14; H,

6.56; N, 0.81.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-butanoylamino-2-deoxy-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (8). Compound 5 (830 mg, 0.56 mmol) was treated with

hydrazine monohydrate (0.27 mL, 5.6 mmol) as described for 6, and the resulting

amine was treated with butanoic anhydride (0.36 mL, 2.24 mmol) in MeOH (8 mL)

for 2 h at room temperature. Work-up and column chromatography as described for

7 gave 8 (792 mg, 98%); [a]_Dꢀ 10° (c 2.9, CH₂Cl₂); IR (film) 3400, 2950, 1670,

1530, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.75 (t, 3H, CH₃CH₂CH₂C(O)NH),

1.02 (m, 2H, Me₃SiCH₂CH₂), 1.42 (m, 2H, CH₃CH₂CH₂C(O)NH), 1.60 (m, 2H,

CH₃CH₂CH₂C(O)NH), 7.11–7.64 (m, 40H, 8Ph).

Anal. Calcd for C₈₃H₉₉NO₁₆Si: C, 71.47; H, 7.15; N, 1.00. Found: C, 71.44; H,

6.90; N, 0.75.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-octanoylamino-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (9). The phthalimido group of 5 (500 mg, 0.34 mmol)

was cleaved in ethanol (6 mL) by treatment with hydrazine monohydrate (0.17 mL, 3.4

mmol) as described for 6, and the resulting amine was reacted with octanoic anhydride

(0.41 mL, 1.4 mmol) in MeOH (5 mL) for 12 h at room temperature. Work-up and

column chromatography as described for 7 gave 9 (417 mg, 84%) as a syrup;

[a]_Dꢀ 8.7° (c 8.3, CH₂Cl₂); IR (film) 3400, 2950, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1}; H

NMR (CDCl₃) d 0.82 (t, 3H, CH₃(CH₂)₅CH₂C(O)NH), 1.03 (m, 2H, Me₃SiCH₂CH₂),

1.26 (m, 10H, CH₃(CH₂)₅CH₂C(O)NH), 1.60 (m, 2H, CH₃(CH₂) CH₂C(O)NH), 7.15–

7.68 (m, 40H, 8Ph).

Anal. Calcd for C₈₇H₁₀₇NO₁₆Si: C, 72.02; H, 7.43; N, 0.97. Found: C, 71.78; H,

7.05; N, 0.90.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-lauroylamino-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (10). The amine obtained from 5 (300 mg, 0.21 mmol)

as described for 6, was treated with lauric acid (210 mg, 1.05 mmol) and 1-(3-di-

methylaminopropyl)-3-ethylcarbodiimide hydrochloride (WSC;200 mg, 1.05 mmol) in

CH₂Cl₂(10 mL) for 12 h at room temperature. After completion of the reaction, the

mixture was concentrated and the residue was taken up in CH₂Cl₂, and washed with sat

Na₂CO₃, 2M HCl and water, dried (Na₂SO₄), and concentrated. Column chromato-

graphy (AcOEt:hexane = 1:3) of the residue on silica gel gave 10 (295 mg, 95%) as a

syrup; [a]_Dꢀ 8.0° (c 1.0, CH₂Cl₂); IR (film) 3400, 2950, 1660, 1530, 860, 840, 700

cm ^ꢀ^{1 1}H NMR (CDCl₃) d 0.87 (t, 3H, CH₃(CH₂)₉CH₂C(O)NH), 0.97 (m, 2H,

;

Me₃SiCH₂CH₂), 1.05–1.32 (m, 18H, CH₃(CH₂)₉CH₂C(O)NH), 1.63 (m, 2H,

CH₃(CH₂)₉CH₂C(O)NH), 4.99 (d, 1H, J=10.4 Hz, NH), 7.07–7.32 (m, 40H, 8Ph).

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SIALYL-a-(2 3)-NEOLACTOTETRAOSE DERIVATIVES

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Anal. Calcd for C₉₁H₁₁₅NO₁₆Si: C, 72.53; H, 7.69; N, 0.93. Found: C, 72,24; H,

7.55; N, 0.87.

2-(Trimethylsilyl)ethyl (3,6-di-O-benzyl-2-deoxy-2-palmitoylamino-b-^D-gluco-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (11). Compound 5 (300 mg, 0.21 mmol) in ethanol (20

mL) was treated with hydrazine monohydrate (0.56 mL, 8.4 mmol) as described for 6.

The resulting amine was reacted with palmitic acid (197 mg, 1.05 mmol) and WSC

(264 mg, 1.05 mmol) in CH₂Cl₂(20 mL) for 36 h at room temperature. Work-up and

column chromatography as described for 10 gave 11 (304 mg, 94%) as a syrup;

[a]_Dꢀ 8.7° (c 1.2, CH₂Cl₂); IR (film) 3400, 2950, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1}; H

NMR (CDCl₃) d 0.88 (t, 3H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.02 (m, 2H, Me₃SiCH₂CH₂),

1.13–1.26 (m, 26H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.63 (m, 2H, CH₃(CH₂)₁₃CH₂C(O)NH),

5.00 (d, 1H, J =9.7 Hz, NH), 7.08–7.32 (m, 40H, 8Ph).

Anal. Calcd for C₉₅H₁₂₃NO₁₆Si: C, 73.00; H, 7.93; N, 0.90. Found: C, 72.73; H,

7.84; N, 0.82.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dide-

oxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-benzoyl-b-

D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-deoxy-2-phthalimido-b-D-glucopyra-

nosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-

b-^D-glucopyranoside (14). To a solution of 12 (103 mg, 0.10 mmol) and 5 (100 mg,

0.069 mmol) in CH₂Cl₂(2 mL) was added MS4A (100 mg) and the reaction mixture

was stirred for 6 h at room temperature, then cooled to 0°C. A mixture of di-

methyl(methylthio)sulfonium triflate (DMTST; 110 mg, 0.41 mmol) and MS4A (90

mg) was added, and the reaction mixture was stirred for 24 h at 7°C, being monitored

by TLC. The solids were collected and washed with CH₂Cl₂. The filtrate and washings

were combined, and washed with sat Na₂CO₃and water, dried (Na₂SO₄), and con-

centrated. Column chromatography (CH₂Cl₂:MeOH =100:1) of the residue on silica gel

gave 14 (113 mg, 68.9%) as an amorphous mass; [a]_D+14.4° (c 2.1, CH₂Cl₂); IR(film)

3400, 2950, 1760, 1550, 860, 840, 700 cm ^ꢀ^{1 1}H NMR (CDCl₃) d 0.98 (m, 2H,

;

Me₃SiCH₂CH₂), 1.53 (s, 3H, AcN), 1.80, 1.94, 1.99, 2.17 (4s, 12H, 4AcO), 2.48 (dd,

1H, J= 12.6, 4.21 Hz, H-3e(eq)), 3.84 (s, 3H, MeO), 5.37 ( ꢁ d, 1H, J= 3.2 Hz, H-4d),

5.57 (t, 1H, J_1,2=J_2,3=9.7 Hz, H-2d), 5.74 (m, 1H, H-8e), 7.00–8.06 (m, 59H, 11Ph,

NPhth).

Anal. Calcd for C₁₃₄H₁₄₄N₂O₃₇Si: C, 66.99; H, 6.04; N, 1.17. Found: C, 66.79;

H, 5.91; N, 1.14.

Coupling of 12 (0.2 mmol) with 6–11 (0.15 mmol) performed as described

for 14 gave 15 (86.5%), 16 (74.5%), 17 (78.4%), 18 (76%), 19 (64%), and 20

(75.4%), respectively.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-

D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-benzoyl-b-D-

galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-carbobenzoxyamino-2-deoxy-b-^D-glu-

copyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-D-glucopyranoside (15). An amorphous mass; [a]_D+4.3° (c 3.0, CH₂Cl₂);

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FUKUNAGA ET AL.

IR(KBr) 3400, 2920, 1740, 1680, 1515, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.00

(m, 2H, Me₃SiCH₂CH₂), 1.48 (s, 3H, AcN), 1.75, 1.90, 1.95, 2.13 (4s, 12H, 4AcO), 2.44

(dd, 1H, J= 12.5, 4.22 Hz, H-3e(eq)), 3.80 (s, 3H, MeO), 4.80 (m, 1H, H-4e), 5.33 (d,

1H, J_3,4=3.4 Hz, H-4d), 5.50 (t, 1H, J_1,2=J_2,3=9.4 Hz, H-2d), 5.69 (m, 1H, H-8e), 7.01–

8.25 (m, 60H, 12Ph).

Anal. Calcd for C₁₃₃H₁₄₆N₂O₃₇Si: C, 66.76; H, 6.15; N, 1.17. Found: C, 66.51;

H, 5.91; N, 0.82.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(2-benzoylamino-3,6-di-O-benzyl-2-deoxy-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (16). An amorphous mass; [a]_D+ 3.1° (c 1.8, CH₂Cl₂);

IR (film) 3400, 2950, 1750, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.00

(m, 2H, Me₃SiCH₂CH₂), 1.50 (s, 3H, AcN), 1.78, 1.92, 1.97, 2.15 (4s, 12H, 4AcO), 2.47

(dd, 1H, J =12.3, 4.3 Hz, H-3e(eq)), 3.83 (s, 3H, MeO), 5.23 (dd, 1H, J_6,7=2.5 Hz,

_7,8=9.6 Hz, H-7e), 5.38 (d, 1H, J_3,4=2.7 Hz, H-4d), 5.53 (t, 1H, J_1,2= J_2,3=9.7 Hz, H-

2d), 5.71 (m, 1H, H-8e), 6.11 (d, 1H, J= 8.6 Hz, NH), 6.95–8.02 (m, 60H, 12Ph).

Anal. Calcd for C₁₃₃H₁₄₆N₂O₃₆Si: C, 67.21; H, 6.19; N, 1.18. Found: C, 67.17;

H, 6.18; N, 1.14.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-butanoylamino-2-deoxy-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (17). An amorphous mass; [a]_D+ 3.4° (c 1.3,

CH₂Cl₂); IR (film) 3350, 2950, 1750, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1 1}H NMR

;

(CDCl₃) d 0.74 (t, 3H, CH₃CH₂CH₂C(O)NH), 1.03 (m, 2H, Me₃SiCH₂CH₂) 1.36 (m,

2H, CH₃CH₂CH₂C(O)NH), 1.51 (s, 3H, AcN), 1.64 (m, 2H, CH₃CH₂CH₂C(O)NH),

1.75, 1.89, 1.95, 2.15 (4s, 12H, 4AcO), 2.47 (dd, 1H, J= 12.6, 4.39 Hz, H-3e(eq)),

3.81 (s, 3H, MeO), 5.38 (d, 1H, J_3,4=3.2 Hz, H-4d), 5.50 (t, 1H, J_1,2=J_2,3= 10.9 Hz,

H-2d), 5.71 (m, 1H, H-8e), 7.08–8.04 (m, 55H, 11Ph).

Anal. Calcd for C₁₃₀H₁₄₈N₂O₃₆Si: C, 66.65; H, 6.37; N, 1.20. Found: C, 66.43;

H, 6.26; N, 1.09.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-deoxy-2-octanoylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (18). An amorphous mass; [a]_D+3.3° (c 5.0, CHCl₃);

IR (film) 3350, 2950, 1740, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1}; ¹H NMR (CDCl₃) d 0.81 (t,

3H, J= 6.9 Hz, CH₃(CH₂)₅CH₂C(O)NH), 0.99 (m, 2H, Me₃SiCH₂CH₂), 1.22 (m, 10H,

CH₃(CH₂)₅CH₂C(O)NH), 1.52 (s, 3H, AcN), 1.67 (m, 2H, CH₃(CH₂)₅CH₂C(O)NH), 1.78,

1.92, 1.97, 2.16 (4s, 12H, 4AcO), 2.45 (dd, 1H, J= 12.5, 4.0 Hz, H-3e(eq)), 3.83 (s, 3H,

MeO), 5.38 (d, 1H, J_3,4= 3.0 Hz, H-4d), 5.54 (t, 1H, J_1,2=J_2,3=9.9 Hz, H-2d), 5.70 (m, 1H,

H-8e), 7.06–8.05 (m, 55H, 11Ph).

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Anal. Calcd for C₁₃₄H₁₅₆N₂O₃₆Si: C, 67.10; H, 6.56; N, 1.17. Found: C, 66.93;

H, 6.48; N, 1.08.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dide-

oxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-benzoyl-b-

D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-deoxy-2-lauroylamino-b-D-glucopyr-

anosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-

b-^D-glucopyranoside (19). An amorphous mass; [a]_D+4.9° (c 0.41, CH₂Cl₂); IR

(film) 3400, 2950, 1740, 1660, 1530, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.87

(t, 3H, CH₃(CH₂)₉CH₂C(O)NH), 1.00 (m, 2H, Me₃SiCH₂CH₂), 1.23 (m, 18H,

CH₃(CH₂)₉CH₂C(O)N H), 1.49 (s, 3H, AcN), 1.63 (m, 2H, CH₃(CH₂)₉CH₂C(O)N H),

1.78, 1.92, 1.96, 2.14 (4s, 12H, 4AcO), 2.45 (dd, 1H, J= 12.1, 4.23 Hz, H-3e(eq)), 3.82

(s, 3H, MeO), 5.34 (d, 1H, J_3,4= 3.2 Hz, H-4d), 5.47 (t, 1H, J_1,2=J_2,3= 10.2 Hz,

H-2d), 5.72 (m, 1H, H-8e), 7.03–8.07 (m, 55H, 11Ph).

Anal. Calcd for C₁₃₈H₁₆₄N₂O₃₆Si: C, 67.52; H, 6.73; N, 1.14. Found: C, 67.29;

H, 6.62; N, 0.92.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-deoxy-2-palmitoylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (20). An amorphous mass; [a]_D+ 3.3° (c 0.48,

CH₂Cl₂); IR (film) 3350, 2950, 1740, 1660, 1530, 860, 840, 700 cm ^ꢀ^{1 1}H NMR

;

(CDCl₃) d 0.88 (t, 3H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.01 (m, 2H, Me₃SiCH₂CH₂), 1.25

(m, 26H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.49 (s, 3H, AcN), 1.66 (m, 2H,

CH₃(CH₂)₁₃CH₂C(O)NH), 1.78, 1.92, 1.96, 2.14 (4s, 12H, 4AcO), 2.45 (dd, 1H,

J= 12.6, 4.0 Hz, H-3e(eq)), 3.82 (s, 3H, MeO), 5.34 (d, 1H, J_3,4= 2.7 Hz, H-4d), 5.48

(t, 1H, J_1,2= J_2,3=10.2 Hz, H-2d), 5.68 (m, 1H, H-8e), 7.04–8.09 (m, 55H, 11Ph).

Anal. Calcd for C₁₄₂H₁₇₂N₂O₃₆Si: C, 67.92; H, 6.90; N, 1.12. Found: C, 67.72;

H, 6.71; N, 0.89.

2-(Trimethylsilyl)ethyl (methyl 5-acetoxyacetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-deoxy-2-lauroylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-benzyl-b-^D-glucopyranoside (21). To a solution of 13 (132 mg, 0.12 mmol) and

10 (150 mg, 99 mmol) in CH₂Cl₂(1 mL) was added MS4A (150 mg), the reaction

mixture was stirred for 3 h at room temperature and then cooled to 0°C. To the mixture

was added TMSOTf (3.8 mL, 19.9 mmol), and the reaction mixture was stirred for 12 h

at 0°C, being monitored by TLC. The solids were collected and washed with CH₂Cl₂,

and the filtrate and washings were combined and washed with sat Na₂CO₃and water,

dried (Na₂SO₄), and concentrated. Column chromatography (CH₂Cl₂:MeOH = 80:1) of

the residue on silica gel gave 21 (200 mg, 81%) as an amorphous mass; [a]_D+2.8° (c

1.6, CHCl₃); IR (film) 3400, 2950, 1750, 1660, 1540, 860, 840, 700 cm ^{ꢀ 1}; H NMR

(CDCl₃) d 0.87 (t, 3H, CH₃(CH₂)₉CH₂C(O)NH), 1.00 (m, 2H, Me₃SiCH₂CH₂), 1.21

(m, 18H, CH₃(CH₂)₉CH₂C(O)NH), 1.47 (m, 2H, CH₃(CH₂)₉CH₂C(O)NH), 1.77, 1.89,

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FUKUNAGA ET AL.

1.96, 2.14, 2.15 (5s, 15H, 5AcO), 2.46 (dd, 1H, J= 12.5, 4.39 Hz, H-3e(eq)), 3.83 (s,

3H, MeO), 4.20, 4.46 (2d, 2H, J_gem=15.4 Hz, AcOCH₂C(O)NH), 5.17 (dd, 1H,

J=2.56, 9.52 Hz, H-7e), 5.34 (d, 1H, J =3.29 Hz, H-4d), 5.48 (dd, 1H, J =8.06, 9.88

Hz, H-2d), 5.68 (m, 1H, H-8e), 5.72 (d, 1H, J_NH,5=10.0 Hz, NH), 7.01–8.24 (m,

55H, 11Ph).

Anal. Calcd for C₁₄₀H₁₆₆N₂O₃₈Si: C, 66.92; H, 6.66; N, 1.11. Found: C, 66.86;

H, 6.44; N, 1.08.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-(b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-benzyl-2-

carbobenzyloxyamino-2-deoxy-b-^D-glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-D-

galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-^D-glucopyranoside (22). To a solu-

tion of 15 (136 mg, 57 mmol) in MeOH (8 mL) was added a catalytic amount of

sodium methoxide, the reaction mixture was stirred for 12 h at room temperature and

then water was added. After completion of the reaction, it was neutralized with

Amberlite IR-120(H ⁺) resin. The resin was filtered off and washed with MeOH, and

the combined filtrate and washings was concentrated. Column chromatography (MeOH)

of the residue on Sephadex LH-20 gave 22 (108 mg, 95%) as an amorphous mass;

[a]_Dꢀ 6.2° (c 0.45, MeOH); IR (KBr) 3400, 2950, 1730, 1620, 1560, 860, 840, 700

cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.00 (m, 2H, Me₃SiCH₂CH₂), 2.00 (s, 3H, AcN), 2.89 (dd,

1H, J=12.5, 4.2 Hz, H-3e(eq)), 7.06–7.27 (m, 45H, 9Ph).

Anal. Calcd for C₁₀₃H₁₂₄N₂O₃₀Si: C, 65.17; H, 6.58; N, 1.48. Found: C, 65.11;

H, 6.49; N, 1.35.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-amino-2-deoxy-b-D-

glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyranoside (23). A

solution of 22 (108 mg, 57 mmol) in acetic acid (8 mL) was treated with hydrogen over

Pd(OH)₂(110 mg) for 5 days at 40°C. The solid was filtered off and the filtrate was

concentrated. Column chromatography (MeOH:H₂O =1:1) of the residue on Sephadex

LH-20 gave 23 (43 mg, 73%) as an amorphous mass (ninhydrin positive); [a]_Dꢀ 0.46°

(c 0.87, MeOH); IR (KBr) 3400, 2900, 1670, 1590, 860, 840 cm ^ꢀ^{1 1}H NMR

;

(CD₃OD) d 1.00 (m, 2H, Me₃SiCH₂CH₂), 2.00 (s, 3H, AcN), 2.89 (dd, 1H, J= 12.5,

4.22 Hz, H-3e(eq)).

Anal. Calcd for C₄₀H₇₂N₂O₂₈Si: C, 45.45; H, 6.87; N, 2.65. Found C, 45.37; H,

6.63; N, 2.43.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-deoxy-2-phthalimido-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (24). A solution of 14 (113 mg, 47 mmol) in acetic

acid (2 mL) and EtOH (12 mL) was treated with hydrogen over Pd-C (113 mg) for 5

days at 40°C. The solid was filtered off and the filtrate was concentrated. The residue

was acetylated with acetic anhydride (0.15 mL) in pyridine (1.5 mL) for 12 h at room

temperature. The mixture was diluted with CH₂Cl₂, and the solution was washed with

2 M HCl and water, dried (Na₂SO₄) and concentrated. Column chromatography

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399

(CH₂Cl₂:MeOH = 50:1) of the residue on silica gel gave 24 (74 mg, 78%) as an

amorphous mass; [a]_D+25.7° (c 1.5, CHCl₃); IR (film) 3450, 2950, 1740, 1520, 860,

840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.95 (m, 2H, Me₃SiCH₂CH₂), 1.57 (s, 3H, AcN),

1.80–2.14 (s, 36H, 12AcO), 2.46 (dd, 1H, J =11.7, 4.02 Hz, H-3e(eq)), 3.73 (s, 3H,

MeO), 5.68 (m, 1H, H-8e), 7.49–8.21 (m, 19H, 3Ph, NPhth).

Anal. Calcd for C₉₄H₁₁₂N₂O₄₅Si: C, 55.95; H, 5.59; N, 1.39. Found: C, 55.79; H,

5.55; N, 1.23.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-benzoylamino-2-deoxy-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (25). A solution of 16 (246 mg, 104 mmol) in acetic

acid (2 mL) and EtOH (15 mL) was treated with hydrogen over Pd-C (250 mg) for 3

days at 40°C. Work-up, acetylation of the free hydroxyls, and column chromatography

as described for 24 gave 25 (138 mg, 67%) as an amorphous mass; [a]_D+18.1° (c 0.54,

CHCl₃); IR (film) 3400, 2950, 1750, 1650, 1530, 860, 840, 700 cm ^ꢀ^{1 1}H NMR

;

(CDCl₃) d 0.96 (m, 2H, Me₃SiCH₂CH₂), 1.55 (s, 3H, AcN), 1.78–2.14 (s, 36H,

12AcO), 2.50 (dd, 1H, J=12.6, 4.39 Hz, H-3e(eq)), 3.82 (s, 3H, MeO), 5.63 (m, 1H, H-

8e), 7.40–8.22 (m, 20H, 3OBz, NHBz).

Anal. Calcd for C₉₃H₁₁₄N₂O₄₄Si: C, 56.08; H, 5.77; N, 1.41. Found: C, 56.06; H,

5.74; N, 1.14.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-butanoylamino-2-deoxy-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (26). Hydrogenolysis of 17 (392 mg, 168 mmol) in

acetic acid (1.5 mL) and EtOH (10 mL) was performed over Pd-C (400 mg) for 3 days

at 40°C. The residue was acetylated with acetic anhydride (0.21 mL) in pyridine (2

mL) for 12 h at room temperature. Work-up, acetylation, and column chromatography

as described for 24 gave 26 (253 mg, 77%) as an amorphous mass; [a]_D+ 18.3° (c 5.1,

CHCl₃); IR (film) 3350, 2950, 1740, 1660, 1530, 860, 840, 700 cm ^ꢀ^{1 1}H NMR

;

(CDCl₃) d 0.85 (t, 3H, J=6.9 Hz, CH₃CH₂CH₂C(O)NH), 0.95 (m, 2H, Me₃SiCH₂CH₂),

1.54 (m, 2H, CH₃CH₂CH₂C(O)NH), 1.58 (s, 3H, AcN), 1.76 (m, 2H,

CH₃CH₂CH₂C(O)NH), 1.90–2.12 (s, 36H, 12AcO), 2.46 (dd, 1H, J=12.4, 4.02 Hz,

H-3e(eq)), 3.70 (s, 3H, MeO), 5.62 (m, 1H, H-8e), 7.39–8.20 (m, 15H, 3Bz).

Anal. Calcd for C₉₀H₁₁₆N₂O₄₄Si: C, 55.21; H, 5.97; N, 1.43. Found: C, 55.15; H,

5.72; N, 1.31.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-deoxy-2-octanoylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (27). Hydrogenolysis of 18 (249 mg, 104 mmol) in

EtOH (15 mL) was performed over Pd(OH)₂(250 mg) for 12 h at 40°C, and the

product was acetylated as described for 24 to give 27 (191 mg, 92%) as an amorphous

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mass; [a]_D+10.3° (c 0.87, CHCl₃); IR (KBr) 3400, 2960, 1750, 1690, 1540, 860,

840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.86 (t, 3H, CH₃(CH₂)₅CH₂C(O)NH), 0.97 (m,

2H, Me₃SiCH₂CH₂), 1.25 (m, 10H, CH₃(CH₂)₅CH₂C(O)NH), 1.53 (s, 3H, AcN),

1.77 (m, 2H, CH₃(CH₂)₅CH₂C(O)NH), 1.91–2.13 (s, 36H, 12AcO), 2.46 (dd, 1H,

J=12.4, 4.30 Hz, H-3e(eq)), 3.81 (s, 3H, MeO), 5.63 (m, 1H, H-8e), 7.43–8.20 (m,

15H, 3Ph).

Anal. Calcd for C₉₄H₁₂₄N₂O₄₄Si: C, 56.06; H, 6.21; N, 1.39. Found: C, 55.90; H,

5.94; N, 1.39.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-deoxy-2-lauroylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (28). Hydrogenolysis of 19 (380 mg, 160 mmol) and

subsequent acetylation as described for 27 gave 28 (279 mg, 87%) as an amorphous

mass; [a]_D+ 22.4° (c 0.41, CH₂Cl₂); IR (film) 3450, 2950, 1750, 1660, 1540, 860, 840,

700 cm^{ꢀ 1}; H NMR (CDCl₃) d 0.85 (t, 3H, CH₃(CH₂)₉CH₂C(O)NH), 0.90 (m, 2H,

Me₃SiCH₂CH₂), 1.23 (m, 18H, CH₃(CH₂)₉CH₂C(O)NH), 1.52 (s, 3H, AcN), 1.56 (m,

2H, CH₃(CH₂)₉CH₂C(O)NH), 1.73–2.14 (s, 36H, 12AcO), 2.45 (dd, 1H, J=12.1, 4.23

Hz, H-3e(eq)), 3.87 (s, 3H, MeO), 5.78 (m, 1H, H-8e), 7.43–8.19 (m, 15H, 3Ph).

Anal. Calcd for C₉₈H₁₃₂N₂O₄₄Si: C, 56.86; H, 6.43; N, 1.35. Found: C, 56.67; H,

6.34; N, 1.31.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-deoxy-2-palmitoylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (29). Hydrogenolysis of 20 (345 mg, 140 mmol) and

subsequent acetylation as described for 27 gave 29 (249 mg, 86%) as an amorphous

mass; [a]_D+ 21.9° (c 0.42, CH₂Cl₂); IR (film) 3400, 2950, 1740, 1660, 1540, 860, 840,

700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.86 (t, 3H, CH₃(CH₂)₁₃CH₂C(O)NH), 0.91 (m, 2H,

Me₃SiCH₂CH₂), 1.22 (m, 26H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.53 (s, 3H, AcN), 1.55 (m,

2H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.78–2.10 (s, 36H, 12AcO), 2.49 (dd, 1H, J =12.6, 4.02

Hz, H-3e(eq)), 3.87 (s, 3H, MeO), 5.61 (m, 1H, H-8e), 7.42–8.23 (m, 3H, 15Ph).

Anal. Calcd for C₁₀₂H₁₄₀N₂O₄₄Si: C, 57.62; H, 6.64; N, 1.32. Found: C, 57.38;

H, 6.38; N, 1.26.

2-(Trimethylsilyl)ethyl (methyl 5-acetoxyacetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(3,6-di-O-acetyl-2-deoxy-2-lauroylamino-b-D-

glucopyranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-

O-acetyl-b-^D-glucopyranoside (30). Hydrogenolysis of 21 (183 mg, 74 mmol) and

subsequent acetylation as described for 27 gave 30 (133 mg, 86%) as an amorphous

mass; [a]_D+9.2° (c 1.3, CHCl₃); IR (film) 3400, 2950, 1750, 1660, 1540, 860, 840,

700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.86 (t, 3H, J= 6.9 Hz, CH₃(CH₂)₉CH₂C(O)NH), 0.93

(m, 2H, Me₃SiCH₂CH₂), 1.23 (m, 18H, CH₃(CH₂)₉CH₂C(O)NH), 1.51 (m, 2H,

CH₃(CH₂)₉CH₂C(O)NH), 1.58 (t, 1H, J= 12.6 Hz, H-3e(ax)), 1.87–2.13 (s, 39H,

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SIALYL-a-(2 3)-NEOLACTOTETRAOSE DERIVATIVES

401

13AcO), 2.47 (dd, 1H, J =12.6, 4.35 Hz, H-3e(eq)), 3.82 (s, 3H, MeO), 4.19, 4.45 (2d,

2H, J_gem=15.3 Hz, AcOCH₂C(O)NH), 5.20 (dd, 1H, J=2.74, 9.61 Hz, H-7e), 5.35 (d,

1H, J= 3.20 Hz, H-4d), 5.38 (dd, 1H, J= 8.01, 10.1 Hz, H-2d), 5.62 (m, 1H, H-8e), 5.66

(d, 1H, J_NH,5=10.5 Hz, NH), 7.44–8.17 (m, 15H, 3Ph).

Anal. Calcd for C₁₀₀H₁₃₄N₂O₄₆Si: C, 56.44; H, 6.35; N, 1.32. Found: C, 56.28;

H, 6.28; N, 1.08.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-deoxy-2-phthali-

mido-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (31). To a solution of 24 (82 mg, 41 mmol) in MeOH (5 mL) was added a

catalytic amount of sodium methoxide, the reaction mixture was stirred for 24 h at

room temperature and then water was added. After completion of the reaction, the

solution was neutralized with Amberlite IR-120 (H ⁺) resin. The resin was filtered off

and washed with MeOH. The combined filtrate and washings was concentrated to a

residue, which was chromatographed (CHCl₃:MeOH =3:2) on a column of silica gel to

give 31 (35 mg, 73%) as an amorphous mass; [a]_Dꢀ 4.8° (c 0.12, MeOH:H₂O = 1:1);

IR (KBr) 3550, 300, 2930, 1630, 1560, 860, 840 cm ^{ꢀ 1}; H NMR (CD₃OD) d 1.00 (m,

2H, Me₃SiCH₂CH₂), 1.97 (s, 3H, AcN), 2.81 (dd, 1H, J= 11.8, 2.81 Hz, H-3e(eq)),

7.40–7.87 (m, 4H, NPhth).

Anal. Calcd for C₄₈H₇₄N₂O₃₀Si: C, 48.56; H, 6.28; N, 2.36. Found: C, 48.50; H,

6.01; N, 2.36.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-benzoylamino-2-

deoxy-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (32). To a solution of 25 (138 mg, 70 mmol) in MeOH (5 mL) was added sodium

methoxide, the reaction mixture was stirred for 7 days at room temperature then water

was added. Work-up and column chromatography (MeOH:H₂O = 1:1) of the residue

on Sephadex LH-20 gave 32 (77 mg, 96%) as an amorphous mass; [a]_Dꢀ 6.5° (c

0.77, MeOH); IR (KBr) 3550, 3350, 2930, 1620, 1560, 860, 840, 700 cm ^ꢀ^{1 1}H

;

NMR (CD₃OD) d 1.00 (m, 2H, Me₃SiCH₂CH₂), 1.88 (s, 3H, AcN), 2.85 (dd, 1H,

J= 12.6, 4.39 Hz, H-3e(eq)), 7.40–7.87 (m, 5H, NHBz).

Anal. Calcd for C₄₇H₇₆N₂O₂₉Si: C, 48.61; H, 6.60; N,2.41. Found: C, 48.38; H,

6.51; N, 2.17.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-butanoylamino-2-

deoxy-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (33). To a solution of 26 (252 mg, 130 mmol) in MeOH (2 mL) was added

sodium methoxide, the reaction mixture was stirred for 6 days at 35°C and then

water was added. Work-up and column chromatography as described for 32 gave

33 (98 mg, 68%) as an amorphous mass; [a]_Dꢀ 14.6° (c 0.53, MeOH); IR (KBr)

3550, 3400, 2940, 1640, 1560, 860, 840 cm ^ꢀ^{1 1}H NMR (CD₃OD) d 0.95 (t, 3H,

;

CH₃CH₂CH₂C(O)NH), 1.04 (m, 2H, Me₃SiCH₂CH₂), 1.63 (m, 2H, CH₃CH₂-

CH₂C(O)NH), 1.99 (s, 3H, AcN), 2.20 (m, 2H, CH₃CH₂CH₂C(O)NH), 2.81 (dd, 1H,

J= 12.4, 4.02 Hz, H-3e(eq)).

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FUKUNAGA ET AL.

Anal. Calcd for C₄₄H₇₈N₂O₂₉Si: C, 46.89; H, 6.98; N,2.49. Found: C, 46.68; H,

6.73; N, 2.20.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-deoxy-2-octanoyla-

mino-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (34). To a solution of 27 (191 mg, 100 mmol) in MeOH (5 mL) was added

sodium methoxide, the reaction mixture was stirred for 5 days at room temperature and

then water was added. Work-up as described for 32 gave 34 (67 mg, 60%) as an

amorphous mass; [a]_Dꢀ 8.2° (c 0.25, MeOH); IR (KBr) 3550, 3400, 2930, 1640, 1560,

860, 840 cm ^{ꢀ 1}; H NMR (CD₃OD) d 0.87 (t, 3H, CH₃(CH₂)₅CH₂C(O)NH), 0.97 (m,

2H, Me₃SiCH₂CH₂), 1.29 (m, 10H, CH₃(CH₂)₅CH₂C(O)NH), 1.64 (m, 2H,

CH₃(CH₂)₅CH₂C(O)NH), 1.99 (s, 3H, AcN), 2.84 (dd, 1H, J= 12.1, 4.03 Hz, H-3e(eq)).

Anal. Calcd for C₄₈H₈₆N₂O₂₉Si: C, 48.72; H, 7.33; N, 2.37. Found: C, 48.65; H,

7.24; N, 2.07.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-deoxy-2-lauroyla-

mino-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (35) and 2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-

galacto-2-nonulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-

deoxy-2-palmitoylamino-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-

b-^D-glucopyranoside (36). To a solution of 28 (83 mg) or 29 (70 mg) in MeOH

(4 mL) was added sodium methoxide, the reaction mixture was stirred for 7 days

at 35°C and then water was added. Work-up and column chromatography as

described for 32 gave 35 (48 mg, 97%) or 36 (28 mg, 67%) as an amorphous mass;

35, [a]_Dꢀ 10.9° (c 1.0, MeOH); IR (KBr) 3550, 3360, 2930, 1640, 1540, 860, 840

cm ^{ꢀ 1}; H NMR (CD₃OD) d 0.87 (t, 3H, J=6.8 Hz, CH₃(CH₂)₉CH₂C(O)NH), 0.99 (m,

2H, Me₃SiCH₂CH₂), 1.26 (m, 18H, CH₃(CH₂)₉CH₂C(O)NH), 1.60 (m, 2H,

CH₃(CH₂)₉CH₂C(O)NH), 1.98 (s, 3H, AcN), 2.83 (dd, 1H, J= 12.1, 4.23 Hz, H-3e(eq)).

Anal. Calcd for C₅₂H₉₄N₂O₂₉Si: C, 50.39; H, 7.64; N, 2.26. Found: C, 50.23; H,

7.40; N, 2.05.

36, [a]_Dꢀ 9.3° (c 0.58, MeOH); IR (KBr) 3550, 3400, 2950, 1630, 1550, 860,

840 cm^{ꢀ 1}; H NMR (CD₃OD) d 0.87 (t, 3H, J= 7.3 Hz, CH₃(CH₂)₁₃CH₂C(O)NH),

0.99 (m, 2H, Me₃SiCH₂CH₂), 1.26 (m, 26H, CH₃(CH₂)₁₃CH₂C(O)NH), 1.60 (m, 2H,

CH₃(CH₂)₁₃CH₂C(O)NH), 1.98 (s, 3H, AcN), 2.83 (dd, 1H, J= 11.2, 4.02 Hz, H-3e(eq)).

Anal. Calcd for C₅₆H₁₀₂N₂O₂₉Si: C, 51.92; H, 7.94; N, 2.16. Found: C, 51.73; H,

7.74; N, 1.89.

2-(Trimethylsilyl)ethyl (3,5-dideoxy-5-glycolylamino-^D-glycero-a-D-galacto-2-

nonulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-deoxy-2-lauroy-

lamino-b-^D-glucopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyrano-

side (37). To a solution of 30 (133 mg, 63 mmol) in MeOH (1.5 mL) was added

sodium methoxide, the reaction mixture was stirred for 2 days at room temperature and

then water was added. Work-up and column chromatography as described for 32 gave

37 (69 mg, 89%) as an amorphous mass; [a]_Dꢀ 10.6° (c 1.4, MeOH); IR (KBr) 3400,

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SIALYL-a-(2 3)-NEOLACTOTETRAOSE DERIVATIVES

403

2950, 1660, 1550, 860, 840 cm ^{ꢀ 1}

;

¹H NMR (CD₃OD) d 0.87 (t, 3H, J=6.9 Hz,

CH₃(CH₂)₉CH₂C(O)NH), 0.97 (m, 2H, Me₃SiCH₂CH₂), 1.26 (m, 18H,

CH₃(CH₂)₉CH₂C(O)NH), 1.70 (t, 1H, J = 12.6 Hz, H-3e(ax)), 2.22 (m, 2H,

CH₃(CH₂)₉CH₂C(O)NH), 2.84 (dd, 1H, J= 12.6, 4.16 Hz, H-3e(eq)).

Anal. Calcd for C₅₂H₉₄N₂O₃₀Si: C, 49.75; H, 7.55; N, 2.23. Found: C, 49.55; H,

7.51; N, 2.19.

2-(Trimethylsilyl)ethyl (2,3,4,6-tetra-O-acetyl-b-^D-glucopyranosyl)-(1 3)-

(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glucopyra-

noside (40). To a solution of 39 (2.56 g, 6.2 mmol) in CH₂Cl₂(30 mL) were added

MS4A (1.5 g), AgClO₄(0.94 g, 11 mmol), and Ag₂CO₃(1.26 g, 11 mmol), and the

reaction mixture was stirred for 5 h at room temperature. 38 (1.71 g, 6.2 mmol) was

added to the mixture at 0°C and stirring was continued overnight at room temperature.

The solids were removed through celite and washed with CH₂Cl₂. The combined

filtrate and washings was concentrated. Column chromatography (AcOEt:hexane=1:5)

of the residue on silica gel gave 40 (2.02 g, 60%) as a syrup; [a]_Dꢀ 9.3° (c 0.6,

CH₂Cl₂); IR(film) 2950, 1750, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.02 (m, 2H,

Me₃SiCH₂CH₂), 1.82, 1.97, 1.99, 2.13 (4s, 12H, 4AcO), 4.93 (d, 1H, J= 8.1 Hz, H-1c),

7.08–7.34 (m, 30H, 6Ph).

Anal. Calcd for C₇₃H₈₈O₂₀Si: C, 66.75; H, 6.75. Found: C, 66.55; H, 6.73.

2-(Trimethylsilyl)ethyl (b-^D-glucopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-D-

galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-^D-glucopyranoside (41) and 2-(Tri-

methylsilyl)ethyl (4,6-O-benzylidene-b-^D-glucopyranosyl)-(1 3)-(2,4,6-tri-O-ben-

zyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glucopyranoside (42). To

a solution of 40 (2.03 g, 1.5 mmol) in MeOH (20 mL) was added NaOMe, the reaction

mixture was stirred overnight at room temperature, and then neutralized with Amberlite

IR-120 (H ⁺) resin. The resin was filtered off and washed with MeOH. The combined

filtrate and washings was concentrated to give 41 (1.72 g, 97%) as a syrup; [a]_Dꢀ 1.4°

(c 0.56, CH₂Cl₂); H NMR (CDCl₃) d 1.03 (m, 2H, Me₃SiCH₂CH₂), 7.07–7.37 (m,

45H, 9Ph).

To a solution of 41 (2.0 g, 1.8 mmol) in acetonitrile (30 mL) were added Drierite

(1.0 g), benzaldehyde dimethyl acetal (0.52 mL, 3.5 mmol), and a catalytic amount of

p-toluenesulfonic acid, and the reaction mixture was stirred for 2 h at room

temperature. The solution was neutralized with Na₂CO₃, and the solids were filtered

off and washed with CH₂Cl₂. The combined filtrate and washings was concentrated.

Column chromatography (AcOEt:hexane= 1:1) of the residue on silica gel gave 42

(1.72 g, 80%) as an amorphous mass; [a]_Dꢀ 3.0° (c 0.26, CH₂Cl₂); IR(film) 3500,

2950, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.03 (m, 2H, Me₃SiCH₂CH₂), 5.54 (s,

1H, PhCH), 7.08–7.53 (m, 35H, 7Ph).

Anal. Calcd for C₇₂H₈₄O₁₆Si: C, 70.11; H, 6.86. Found: C, 70.25; H, 6.81.

2-(Trimethylsilyl)ethyl (2,3-di-O-benzyl-4,6-O-benzylidene-b-^D-glucopyrano-

syl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-

D-glucopyranoside (43). To a solution of 42 (0.24 g, 0.18 mmol) in DMF (5 mL) was

added 60% NaH in oil (0.17 g, 4.2 mmol) at 0°C. After 30 min, BnBr (0.62 mL, 5.3

mmol) was added to the mixture which was then stirred for 2 h at room temperature.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

404

FUKUNAGA ET AL.

The mixture was extracted with AcOEt and washed with water. The organic layer was

dried over Na₂SO₄and concentrated. Column chromatography (AcOEt:hexane=1:3) of

the residue on silica gel gave 43 (0.24 g, 94%) as a syrup; [a]_Dꢀ 5.9° (c 1.4, CHCl₃);

IR(film) 2950, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.01 (m, 2H, Me₃SiCH₂CH₂),

5.51 (s, 1H, PhCH), 7.05–7.50 (m, 45H, 9Ph).

Anal. Calcd for C₈₆H₉₆O₁₆Si: C, 73.06; H, 6.84. Found: C, 72.91; H, 6.84.

2-(Trimethylsilyl)ethyl (3-O-benzyl-4,6-O-benzylidene-b-^D-glucopyranosyl)-

(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glu-

copyranoside (44). To a solution of 42 (100 mg, 0.08 mmol) in CH₂Cl₂(10 mL)

were added tetrabutylammonium hydrogen sulfate (5.5 mg, 0.02 mmol), BnBr (14 mL,

0.12 mmol), and aq 5% NaOH (5 mL). The mixture was stirred overnight under reflux.

The mixture was diluted with CH₂Cl₂, and washed with water. The organic layer was

dried over Na₂SO₄and concentrated. Column chromatography (AcOEt:hexane=1:3) of

the residue on silica gel gave 44 (85 mg, 80%) as an amorphous mass; [a]_Dꢀ 1.1° (c

1.7, CHCl₃); IR (film) 3500, 2950, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.02 (m,

2H, Me₃SiCH₂CH₂), 5.57 (s, 1H, PhCH), 7.10–7.54 (m, 40H, 8Ph).

Anal. Calcd for C₇₉H₉₀O₁₆Si: C, 71.68; H, 6.85. Found: C, 71.46; H, 6.86.

2-(Trimethylsilyl)ethyl (2-azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-b-^D-

mannopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-

tri-O-benzyl-b-^D-glucopyranoside (46). To a solution of 44 (80 mg, 60.4 mmol) in

pyridine (1.5 mL) were added Tf₂O (42 mL, 0.24 mmol) and N,N-diisopropylethylamine

(22 mL, 0.12 mmol), and the reaction mixture was stirred overnight at room tem-

perature. The mixture was diluted with CH₂Cl₂, and the solution was successively

washed with 2 M HCl, Na₂CO₃, and water. The organic layer was dried (Na₂SO₄), and

concentrated to give 45 as a syrup, which was dissolved in DMF (1.3 mL). To this

solution was added NaN₃(40 mg, 0.64 mmol) and 18-crown-6 (80 mg, 0.32 mmol), the

mixture was stirred overnight at 70°C and then extracted with AcOEt. The extract was

washed with water, dried (Na₂SO₄), and concentrated. Column chromatography

(CHCl₃:MeOH =400:1) of the residue on silica gel gave 46 (73 mg, 92%) as an

amorphous mass; [a]_Dꢀ 37.8° (c 1.5, CHCl₃); IR(film) 2950, 2080, 860, 840, 700

cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.04 (m, 2H, Me₃SiCH₂CH₂), 5.57 (s, 1H, PhCH), 7.03–

7.49 (m, 40H, 8Ph).

Anal. Calcd for C₇₉H₈₉N₃O₁₅Si: C, 70.36; H, 6.65; N, 3.12. Found: C, 70.15; H,

6.64; N, 2.97.

2-(Trimethylsilyl)ethyl (2-acetamido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-b-

D-mannopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-D-galactopyranosyl)-(1 4)-2,3,6-

tri-O-benzyl-b-^D-glucopyranoside (47). To a solution of 46 (73 mg, 54 mmol) in

benzene (1 mL) were added water (54 mL) and triphenylphosphine (30 mg, 0.11 mmol),

the reaction mixture was stirred overnight at room temperature and then concentrated to

dryness. The residue was dissolved in 1:1 CH₂Cl₂-pyridine (2 mL), and acetic anhy-

dride (0.1 mL) was added. The mixture was stirred overnight at room temperature, and

concentrated. Column chromatography (AcOEt:hexane= 1:3) of the residue on silica gel

gave 47 (44 mg, 60%) as an amorphous mass; [a]_Dꢀ 14.4° (c 0.5, CHCl₃); IR(film)

3400, 2950, 1640, 1560, 860, 840, 700 cm ^ꢀ^{1 1}H NMR (CDCl₃) d 1.04 (m, 2H,

;

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

SIALYL-a-(2 3)-NEOLACTOTETRAOSE DERIVATIVES

405

Me₃SiCH₂CH₂), 1.81 (s, 3H, AcN), 5.52 (s, 1H, PhCH), 5.57 (d, 1H, J_NH,2=8.5 Hz,

NH), 7.03–7.49 (m, 40H, 8Ph).

Anal. Calcd for C₈₁H₉₃NO₁₆Si: C, 71.29; H, 6.87; N, 1.03. Found: C, 71.50; H,

6.90; N, 0.78.

2-(Trimethylsilyl)ethyl (2-O-acetyl-3-O-benzyl-4,6-O-benzylidene-b-^D-manno-

pyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-

benzyl-b-^D-glucopyranoside (48). To a solution of 44 (250 mg, 0.18 mmol) in

pyridine (1 mL) were added Tf₂O (127 mL, 0.72 mmol) and N,N-diisopropylethylamine

(66 mL, 0.36 mmol), and the reaction mixture was stirred overnight at room tem-

perature. Work-up as described for 46 gave 45 as a syrup, which was dissolved in DMF

(1.5 mL). To this solution was added cesium acetate (255 mg, 1.3 mmol) and 18-

crown-6 (150 mg, 0.54 mmol), and the mixture was stirred overnight at 70°C. Work-up

as described for 46 gave 48 (187 mg, 73%); [a]_Dꢀ 14.4° (c 0.5, CHCl₃); IR(film)

2950, 1750, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.03 (m, 2H, Me₃SiCH₂CH₂),

1.98 (s, 3H, OAc), 5.46 (br s, 1H, H-2c), 5.58 (s, 1H, PhCH), 7.04–7.49 (m, 40H, 8Ph).

Anal. Calcd for C₈₁H₉₂O₁₇Si: C, 71.24; H, 6.79. Found: C, 71.38; H, 6.82.

2-(Trimethylsilyl)ethyl (2,3,6-tri-O-benzyl-b-^D-glucopyranosyl)-(1 3)-(2,4,6-

tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glucopyranoside

(49). To a solution of 43 (100 mg, 0.71 mmol) in THF (5 mL) was added MS3A (100

mg), and the mixture was stirred for 2 h at room temperature. Sodium cyano-

borohydride (44 mg, 7.1 mmol) was added to the solution, and then hydrogen chloride

in diethyl ether was added dropwise to the stirred mixture: stirring was continued for

30 min. The mixture was neutralized with Et₃N and diluted with CH₂Cl₂and water.

The solids were removed through celite, and the filtrate was washed with water, and

the organic layer was dried over Na₂SO₄and concentrated. Column chromatography

(AcOEt:hexane =1:2) of the residue on silica gel gave 49 (89 mg, 89%) as a syrup;

[a]_Dꢀ 8.5° (c 1.8, CH₂Cl₂); IR(film) 3500, 2950, 860, 840, 700 cm ^{ꢀ 1}

;

¹H NMR

(CDCl₃) d 1.01 (m, 2H, Me₃SiCH₂CH₂), 7.03–7.49 (m, 45H, 9Ph).

Anal. Calcd for C₈₆H₉₈O₁₆Si: C, 72.96; H, 6.98. Found: C, 73.03; H, 6.82.

2-(Trimethylsilyl)ethyl (2-acetamido-3,6-O-benzyl-2-deoxy-b-^D-mannopyrano-

syl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-

D-glucopyranoside (50). Treatment of 47 (202 mg, 0.15 mmol) in THF (5 mL) with

sodium cyanoborohydride (95 mg, 1.5 mmol) was performed as described for 49.

Work-up and column chromatography as described for 49 gave 50 (183 mg, 89%) as a

syrup; [a]_Dꢀ 21.6° (c 4.0, CH₂Cl₂); IR(film) 3500, 2950, 1750, 1640, 1540, 860, 840,

700 cm ^ꢀ^{1 1}H NMR (CDCl₃) d 1.05 (m, 2H, Me₃SiCH₂CH₂), 1.83 (s, 3H, AcN),

;

7.10–7.42 (m, 40H, 8Ph).

Anal. Calcd for C₈₁H₉₅NO₁₆Si: C, 71.18; H, 7.01; N, 1.02. Found: C, 71.15; H,

7.01; N, 1.01.

2-(Trimethylsilyl)ethyl (2-O-acetyl-3,6-di-O-benzyl-b-^D-mannopyranosyl)-

(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glu-

copyranoside (51). Treatment of 48 (187 mg, 0.14 mmol) in THF (5 mL) with

sodium cyanoborohydride (86 mg, 1.4 mmol) was performed as described for 49.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

406

FUKUNAGA ET AL.

Work-up and column chromatography as described for 49 gave 51 (112 mg, 60%) as a

syrup; [a]_Dꢀ 21.5° (c 2.2, CH₂Cl₂); IR(film) 3500, 2950, 1750, 860, 840, 700 cm ^{ꢀ 1}

;

¹H NMR (CDCl₃) d 1.01 (m, 2H, Me₃SiCH₂CH₂), 1.86 (s, 3H, OAc), 7.04–7.48 (m,

40H, 8Ph).

Anal. Calcd for C₈₁H₉₄O₁₇Si: C, 71.13; H, 6.93. Found: C, 70.99; H, 6.97.

DMTST catalyzed couplings of 12 with 49–51 were performed as described for

14–20 to give 52 (73%), 53 (80%), and 54 (84%), respectively.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(2,3,6-tri-O-benzyl-b-D-glucopyranosyl)-(1 3)-

(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-D-glucopyra-

noside (52). An amorphous mass; [a]_D+14.4° (c 2.1, CHCl₃); IR (film) 3400, 2950,

1750, 1640, 1540, 860, 840, 700 cm ^{ꢀ 1}

;

¹H NMR (CDCl₃) d 0.94 (m, 2H,

Me₃SiCH₂CH₂), 1.44 (s, 3H, AcN), 1.76, 1.90, 1.96, 2.14 (4s, 12H, 4AcO), 2.40

(dd, 1H, J=12.8, 4.4 Hz, H-3e(eq)), 3.77 (s, 3H, MeO), 7.02–7.99 (m, 60H, 12Ph).

Anal. Calcd for C₁₃₃H₁₄₇NO₃₆Si: C, 67.58; H, 6.27; N, 0.59. Found: C, 67.44; H,

6.26; N, 0.59.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(2-acetamido-3,6-di-O-benzyl-2-deoxy-b-D-

mannopyranosyl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-

tri-O-benzyl-b-^D-glucopyranoside (53). An amorphous mass; [a]_D+0.97° (c 1.0,

CHCl₃); IR (film) 3400, 2950, 1750, 1640, 1540, 860, 840, 700 cm ^ꢀ^{1 1}H NMR

;

(CDCl₃) d 0.97 (m, 2H, Me₃SiCH₂CH₂), 1.47, 1.76 (2s, 6H, 2AcN), 1.66, 1.89, 1.90,

2.17 (4s, 12H, 4AcO), 2.45 (dd, 1H, J=12.1, 4.4 Hz, H-3e(eq)), 3.80 (s, 3H, MeO),

7.01–8.26 (m, 55H, 11Ph).

Anal. Calcd for C₁₂₈H₁₄₄N₂O₃₆Si: C, 66.42; H, 6.27; N, 1.21. Found: C, 66.22;

H, 6.29; N, 1.20.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(2-O-acetyl-3,6-di-O-benzyl-b-D-mannopyrano-

syl)-(1 3)-(2,4,6-tri-O-benzyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl-b-

D-glucopyranoside (54). An amorphous mass; [a]_D+ 10.9° (c 0.31, CHCl₃); IR (film)

3400, 2950, 1750, 1640, 1540, 860, 840, 700 cm ^{ꢀ 1}; H NMR (CDCl₃) d 1.08 (m,

2H, Me₃SiCH₂CH₂), 1.49 (s, 3H, AcN), 1.66, 1.77, 1.91, 1.95, 2.19 (5s, 15H,

5AcO), 2.40 (dd, 1H, J=12.5, 4.4 Hz, H-3e(eq)), 3.81 (s, 3H, MeO), 7.04–8.26 (m,

55H, 11Ph).

Anal. Calcd for C₁₂₈H₁₄₃NO₃₇Si: C, 66.39; H, 6.22; N, 0.60. Found: C, 66.59; H,

6.26; N, 0.60.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopyranosylonate)-(2 3)-(2,4,6-tri-O-ben-

zoyl-b-^D-galactopyranosyl)-(1 4)-(2,3,6-tri-O-acetyl-b-D-glucopyranosyl)-(1 3)-

(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-acetyl-b-D-glucopyra-

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

SIALYL-a-(2 3)-NEOLACTOTETRAOSE DERIVATIVES

407

noside (55). A solution of 52 (150 mg, 64 mmol) in EtOH (15 mL) was hy-

drogenolyzed over Pd(OH)₂on carbon (150 mg) overnight. The catalyst was filtered off

and the filtrate was concentrated. The residue was acetylated with acetic anhydride (0.1

mL) in pyridine (2 mL) overnight at room temperature. Work-up and column chro-

matography (CHCl₃:MeOH =25:1) on silica gave 55 (85 mg, 69%) as an amorphous

mass; [a]_D+ 36.3° (c 1.6, CHCl₃); IR (film) 3400, 2950, 1750, 1640, 1540, 860, 840,

700 cm^{ꢀ 1}; H NMR (CDCl₃) d 0.91 (m, 2H, Me₃SiCH₂CH₂), 1.76–2.20 (14s, 42H,

AcN and 13AcO), 2.40 (dd, 1H, J= 12.8, 4.4 Hz, H-3e(eq)), 3.86 (s, 3H, MeO), 7.42–

8.17 (m, 15H, 3Ph).

Anal. Calcd for C₈₈H₁₁₁NO₄₅Si: C, 54.74; H, 5.79; N, 0.73. Found: C, 54.63; H,

5.82; N, 0.73.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopranosylonate)-(2 3)-(2,4,6-tri-O-benzoyl-

b-^D-galactopyranosyl)-(1 4)-(2-acetamido-3,6-di-O-acetyl-2-deoxy-b-D-mannopy-

ranosyl)-(1 3)-(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-acetyl-

b-^D-glucopyranoside (56). Hydrogenolysis of 53 (150 mg) and subsequent acetyla-

tion was performed as described for 55 to give 56 (99 mg, 79%) as an amorphous

mass; [a]_D+ 23.4° (c 2.0, CHCl₃); IR (film) 3400, 2950, 1750, 1640, 1540, 860, 840,

700 cm^{ꢀ 1}; H NMR (CDCl₃) d 0.91 (m, 2H, Me₃SiCH₂CH₂), 1.56–2.11 (14s, 42H,

2AcN and 12AcO), 2.46 (dd, 1H, J =12.5, 4.4 Hz, H-3e(eq)), 3.78 (s, 3H, MeO), 7.28–

8.22 (m, 15H, 3Ph).

Anal. Calcd for C₈₈H₁₁₂N₂O₄₄Si: C, 54.77; H, 5.85; N, 1.45. Found: C, 54.88; H,

5.88; N, 1.45.

2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-

dideoxy-^D-glycero-a-D-galacto-2-nonulopranosylonate)-(2 3)-(2,4,6-tri-O-benzoyl-

b-^D-galactopyranosyl)-(1 4)-(2,3,6-tri-O-acetyl-b-D-mannopyranosyl)-(1 3)-

(2,4,6-tri-O-acetyl-b-^D-galactopyranosyl)-(1 4)-2,3,6-tri-O-acetyl-b-D-glucopyra-

noside (57). Hydrogenolysis of 54 (157 mg) and subsequent acetylation was per-

formed as described for 55 to give 57 (135 mg, 95%) as an amorphous mass;

[a]_D+11.7° (c 1.6, CHCl₃); IR (film) 3400, 2950, 1750, 1640, 1540, 860, 840, 700

cm ^{ꢀ 1}; H NMR (CDCl₃) d 0.91 (m, 2H, Me₃SiCH₂CH₂), 1.54–2.13 (14s, 42H, AcN

and 13AcO), 2.40 (dd, 1H, J= 12.5, 4.4 Hz, H-3e(eq)), 3.82 (s, 3H, MeO), 7.43–8.19

(m, 15H, 3Ph).

Anal. Calcd for C₈₈H₁₁₁NO₄₅Si: C, 54.74; H, 5.79; N, 0.73. Found: C, 54.79; H,

5.81; N, 0.73.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-b-D-glucopyranosyl-

(1 3)-b-^D-galactopyranosyl-(1 4)-b-D-glucopyranoside (58). To a solution of

55 (45 mg, 23 mmol) in MeOH (4 mL) was added sodium methoxide, the reaction

mixture was stirred at room temperature overnight and then water was added. Work-up

and column chromatography as described for 32 gave 58 (23 mg, 96%) as an

amorphous mass; [a]_Dꢀ 4.5° (c 0.44, CH₃OH); IR (film) 3500, 3400, 2950, 1640,

1560, 860, 840 cm ^{ꢀ 1}; H NMR (CD₃OD) d 0.91 (m, 2H, Me₃SiCH₂CH₂), 2.00 (s, 3H,

AcN), 2.73 (dd, 1H, J =12.5, 4.4 Hz, H-3e(eq)).

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016

408

FUKUNAGA ET AL.

Anal. Calcd for C₄₀H₇₁NO₂₉Si: C, 45.41; H, 6.76; N, 1.32. Found: C, 45.40; H,

6.62; N, 1.29.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-(2-acetamido-2-deoxy-

b-^D-mannopyranosyl)-(1 3)-b-D-galactopyranosyl-(1 4)-b-D-glucopyranoside

(59). O-Deacylation of 56 (40 mg) as described for 32 gave 59 (20 mg, 89%) as an

amorphous mass; [a]_Dꢀ 11.5° (c 0.40, CH₃OH); IR (film) 3500, 3400, 2950, 1640,

1560, 860, 840 cm ^{ꢀ 1}; H NMR (CD₃OD) d 0.99 (m, 2H, Me₃SiCH₂CH₂), 2.01 (s, 3H,

AcN), 2.05 (s, 3H, AcN), 2.73 (dd, 1H, J= 12.5, 4.4 Hz, H-3e(eq)).

Anal. Calcd for C₄₂H₇₄N₂O₂₉Si: C, 45.90; H, 6.79; N, 2.55. Found: C, 45.98; H,

6.65; N, 2.50.

2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-^D-glycero-a-D-galacto-2-non-

ulopyranosylonic acid)-(2 3)-b-^D-galactopyranosyl-(1 4)-b-D-mannopyranosyl-

(1 3)-b-^D-galactopyranosyl-(1 4)-b-D-glucopyranoside (60). O-Deacylation of

57 (45 mg) as described for 32 gave 60 (27 mg, 98%) as an amorphous mass;

[a]_Dꢀ 14.3° (c 0.54, CH₃OH); IR (film) 3500, 3400, 2950, 1640, 1560, 860, 840

cm ^{ꢀ 1}; ¹H NMR (CD₃OD) d 1.00 (m, 2H, Me₃SiCH₂CH₂), 2.01 (s, 3H, AcN), 2.73 (dd,

1H, J=12.5, 4.5 Hz, H-3e(eq)).

Anal. Calcd C₄₀H₇₁NO₂₉Si: C, 45.41; H, 6.76; N, 1.32. Found: C, 45.45; H, 6.79;

N, 1.32.

ACKNOWLEDGMENTS

This work was supported in part by a Grant-in-Aid (No. 12306007) for Scientific

Research from the Ministry of Education, Science and Culture of Japan. The authors

thank Drs. K. Shinoda and K. Sasaki, Tokyo Research Laboratories, Kyowa Hakko

Kogyo Co., Ltd., for multiform support.

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Received January 21, 2002

Accepted May 29, 2002

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