An efficient and straightforward synthesis of sialyl Lex glycolipid as a potent selectin blocker[1]

Article abstract of DOI:10.1081/CAR-120004336

An efficient synthesis of sialyl Lewis X (sLe^x) glycolipid as a potent selectin blocker is described. 2-(Tetradecyl)hexadecanol which functions as an artificial ceramide, was glycosylated with phenyl 4-O-acetyl-6-O-benzyl-2-deoxy-3-O-(4-methoxy

Full text of DOI:10.1081/CAR-120004336

Journal of Carbohydrate Chemistry
ISSN: 0732-8303 (Print) 1532-2327 (Online) Journal homepage: http://www.tandfonline.com/loi/lcar20
AN EFFICIENT AND STRAIGHTFORWARD SYNTHESIS
OF SIALYL Le X GLYCOLIPID AS A POTENT SELECTIN
BLOCKER[]
Nobumasa Otsubo , Hideharu Ishida & Makoto Kiso
To cite this article: Nobumasa Otsubo , Hideharu Ishida & Makoto Kiso (2002) AN EFFICIENT
AND STRAIGHTFORWARD SYNTHESIS OF SIALYL Le X GLYCOLIPID AS A POTENT SELECTIN
BLOCKER[], Journal of Carbohydrate Chemistry, 21:3, 247-255
To link to this article: http://dx.doi.org/10.1081/CAR-120004336
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J. CARBOHYDRATE CHEMISTRY, 21(3), 247–255 (2002)
AN EFFICIENT AND STRAIGHTFORWARD
SYNTHESIS OF SIALYL LeX GLYCOLIPID
AS A POTENT SELECTIN BLOCKER[1]
*
Nobumasa Otsubo, Hideharu Ishida, and Makoto Kiso
*
Department of Applied Bioorganic Chemistry, Gifu University,
Gifu 501-1193, Japan
ABSTRACT
An efficient synthesis of sialyl Lewis X (sLex) glycolipid as a potent
selectin blocker is described. 2-(Tetradecyl)hexadecanol which functions
as an artificial ceramide, was glycosylated with phenyl 4-O-acetyl-6-O-
benzyl-2-deoxy-3-O-(4-methoxybenzyl)-2-phthalimido-1-thio-b-D-glu-
copyranoside at the first step of the synthetic scheme. The N-ace-
tylglucosamine acceptor carrying the hydrophobic aglycon was then
coupled with sialyl-a-(2 !3)galactose donor to afford the trisaccharide
which upon successive a-L-fucosylation and deprotections, resulted in
sLex glycolipid in quite straightforward steps.
Key Words: Sialyl Lewis X; Selectin; Glycolipid
INTRODUCTION
Selectins are a family of carbohydrate-binding proteins that mediate the tether-
ing and rolling of leukocytes in blood vessel endothelium at the sites of in-
flammation.[2,3] Selectins are also implicated in hematogenous metastasis of some
cancer cells.[4,5] Sialyl Lewis X (sLex) tetrasaccharide, Neu5Aca2 ! 3Galb1 !
4(Fuca1 !3) GlcNAc has been generally recognized as a common ligand for all
*
Corresponding authors. E-mail: isnida@cc.gifu-u.ac.jp; kiso@cc.gifu-u.ac.jp
247
Copyright D 2002 by Marcel Dekker, Inc.
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248
OTSUBO, ISHIDA, AND KISO
Scheme 1. Synthetic analogs of sialyl Lewis X ganglioside.
selectins.[6,7] and therefore, many analogs and mimetics of sLex have been designed
and synthesized[8,9] not only to elucidate the mechanism of selectin recognition but also
to present the targets for novel therapeutic agents against allergy, inflammatory di-
seases, and cancer metastasis.
Previously, we have reported that the sLex glycolipid (1)[10] having 2-(tetra-
decyl)hexadecanol instead of the ceramide is a potent binding inhibitor of three se-
lectins,[11] in spite of the replacement of N-acetyl-D-glucosamine (2) with D-glucose (1)
at the reducing end. As a component of our continuous studies on the structure-activity
relationship of selectin ligand/inhibitor, we describe herein the synthesis of the inherent
sLex glycolipid (2) having N-acetylglucosamine, based not on the strategy employed for
the synthesis of 1 but on a newly developed, straightforward strategy (Scheme 1).
RESULTS AND DISCUSSION
In the retrosynthetic perspective of the glycolipids, the first disconnection of the
molecule is generally placed between the oligosaccharide segment and the lipid
segment. However, this strategy cannot be applied to the sialooligosaccharide with N-
acetylglucosamine at the reducing end, due to the presence of the acid labile sialyl
glycoside bond and the stability of the oxazoline intermediate. Based on these analyses,
we employed a new synthetic strategy where the N-acetylglucosamine was first con-
densed with the lipid segment and subjected to further glycosylations to construct the
desired oligosaccharide structures. This strategy eliminated the laborious protection/
deprotection processes at the anomeric position and improved the overall efficiency of
the synthesis.
Glycosylation of 2-(tetradecyl)hexadecanol (4)[12] with phenyl 4-O-acetyl-6-O-
benzyl-2-deoxy-3-O-(4-methoxybenzyl)-2-phthalimido-1-thio-b-D-glucopyranoside
(3)[13] in dichloromethane for 3 h at room temperature in the presence of N-iodosuc-
˚
cinimide (NIS), trifluoromethanesulfonic acid (TfOH) and powdered 4 A molecular
˚
sieves (4 A MS) resulted in the desired b-glycoside in 84% yield. A significant signal
in the H NMR spectrum of 5 to support the stereochemistry of the newly formed
1
glycosidic linkage was a one-proton doublet at d 5.15 (d, J1,2 =9.5 Hz, H-1 of GlcNAc)
(Scheme 2).
Removal of phthaloyl and acetyl groups in 5 in the presence of hydrazine mono-
hydrate in ethanol for 10 h at 80°C, and subsequent acetamidation with acetic

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SIALYL Lex GLYCOLIPID
249
Scheme 2. Synthesis of sialyl Lewis X glycolipid.
anhydride in methanol afforded the desired glycosyl acceptor 6 in 96% yield. Glycosy-
lation of 6 with methyl (methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-gly-
cero-a-D-galacto-2-nonulopyranosylonate)-(2 ! 3)-2,4,6-tri-O-benzoyl-1-thio-b-D-galac-
topyranoside (7)[14] was carried out in the presence of dimethyl(methylthio)sulfonium
triflate (DMTST)[15,16] and 4 A MS for 12 h at 0°C, to afford the desired trisaccharide
˚
1
derivative 8 in 70% yield. A significant signal in the H NMR spectrum of 8 was a

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250
OTSUBO, ISHIDA, AND KISO
one-proton doublet at d 5.09 (d, J1,2 =9.8 Hz, H-1 of Gal), indicating that the a(2 ! 3)-
sialylgalactose residue was incorporated into the acceptor as a b-glycoside.
For the removal of the 4-methoxybenzyl (MPM) group, the oxidative cleavage
by ceric ammonium nitrate (CAN) in acetonitrile–water has generally been em-
ployed.[13,17] However, due to the low solubility of 8 in acetonitrile–water, we at-
tempted the cleavage of MPM in the presence of trimethylchlorosilane (TMSCl), tin
(II) chloride (SnCl2), and anisole in dichloromethane.[18] Thus, treatment of 8 with the
reagent for 3 h at 18°C afforded the desired trisaccharide acceptor 9 in 94% yield.
Subsequent a-L-fucosylation of 9 in benzene at 7°C in the presence of phenyl 2,3,4-tri-
O-benzyl-1-thio-b-L-fucopyranoside (10),[19] NIS, TfOH and 4 A MS afforded the
˚
protected sLex derivative 11 in 95% yield. This structure was supported by a char-
acteristic doublet at d 5.21 (d, J1,2 =3.4 Hz, H-1 of Fuc). Hydrogenolytic removal of
the benzyl group in 11 over palladium hydroxide in ethanol for 24 h at 40°C and
subsequent acetylation of the free hydroxyls with acetic anhydride and pyridine for 12
h at room temperature afforded the fully acylated sLex derivative 12 in 93% yield.
Finally, O-deacylation of 12 with sodium methoxide in methanol for 24 h at room
temperature, and subsequent saponification of the methyl ester afforded the target sLex
neoglycolipid 2 in a quantitative yield.
In summary, by using a novel synthetic strategy, we accomplished the efficient
and straightforward synthesis of the pharmaceutically active homolog of sLex glyco-
lipid in 46% yields over seven steps following the preparations of corresponding build-
ing blocks.
EXPERIMENTAL
General Methods. Specific rotations were determined with a Horiba SEPA-300 high
1
sensitive polarimeter at 25°C, and H NMR spectra were recorded at 400 MHz with a
Varian Inova 400, or 500 MHz with a Varian Inova 500 spectrometer using deuterated
solvents (CDCl3, CD3OD) with TMS as the internal standard. Preparative TLC was
performed on silica gel (E. Merck), and column chromatography on silica gel (Fuji
Silysia Co., 300 mesh) was carried out with the solvent system (v/v) specified. Con-
centrations and evaporations were conducted in vacuo.
2-(Tetradecyl)hexadecyl 4-O-acetyl-6-O-benzyl-2-deoxy-3-O-(4-methoxybenzyl)-2-
phthalimido-b-D-glucopyranoside (5). To a solution of 3 (200 mg, 0.30 mmol)
and 2-(tetradecyl)hexadecanol (4, 289 mg, 0.76 mmol) in dry CH2Cl2 (8 mL) was
˚
˚
added powdered 4 A molecular sieves (4 A MS, 0.6 g), and the mixture was stirred for
3 h at room temperature. N-Iodosuccinimide (NIS, 206 mg, 0.91 mmol) and trifluor-
omethanesulfonic acid (TfOH, 4.0 mL, 45.2 mmol) were then added to the mixture, and
stirred for 3 h at room temperature. The solids were filtered and washed with CHCl3.
The combined filtrate and washings were further washed with M NaHCO3 and M
Na2S2O3, dried (Na2SO4) and concentrated. Column chromatography (1:6 EtOAc-hex-
ane) of the residue on silica gel gave 5 (251 mg, 84%) as an amorphous mass:
1
[a]D +38.2° (c 1.1 CHCl3); IR (film) 2950, 1750, 1720, 700 cmÀ1; H NMR (CDCl3): d
0.90 (t, 6H, J= 6.9 Hz, 2CH3), 1.11–1.43 (m, 53H, 26CH2 and CH), 1.99 (s, 3H, AcO),
3.19 (dd, 1H, Jgem =9.1, Jvic = 6.6 Hz, OCH2C), 3.61 (s, 3H, MeO), 3.78 (m, 2H, H-5

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SIALYL Lex GLYCOLIPID
251
and OCH2C), 4.22 (dd, 1H, J2,3 = 9.5, J3,4 =8.4 Hz, H-3), 4.43 (t, 1H, J1,2 =9.5 Hz, H-2),
5.12 (t, 1H, J4,5 = 8.4 Hz, H-4), 5.15 (d, 1H, H-1), 6.44, 6.94 (2d, 4H, J=8.1, 8.4 Hz,
MeOPh), 7.23–7.84 (m, 9H, Ph and phthaloyl-H).
Anal. Calcd for C61H91NO9 (982.40): C, 74.58; H, 9.34; N, 1.43. Found: C,
74.51; H, 9.17; N, 1.34.
2-(Tetradecyl)hexadecyl 2-acetamido-6-O-benzyl-2-deoxy-3-O-(4-methoxybenzyl)-
b-D-glucopyranoside (6). To a solution of 5 (450 mg, 0.46 mmol) in EtOH (20
mL) was added NH2NH2ÁH2O (1.0 mL, 20.5 mmol), and the mixture was refluxed for
10 h with stirring. The solids were filtered and washed with CHCl3, and the filtrate was
concentrated. This residue was dissolved in MeOH (14 mL) and CH2Cl2 (4 mL), and
treated with Ac2O (0.42 mL, 4.49 mmol) for 14 h at room temperature, then con-
centrated. Column chromatography (1:2 EtOAc-hexane) of the residue on silica gel
gave 6 (377 mg, 96%) as an amorphous mass: [a]D À 8.8° (c 1.4 CHCl3); IR (film)
1
3550, 3350, 2950, 1680, 1520, 700 cm À 1; H NMR (CDCl3): d 0.91 (t, 6H, J=6.9 Hz,
2CH3), 1.20–1.37 (m, 53H, 26CH2 and CH), 1.92 (s, 3H, AcN), 3.27 (dd, 1H,
J
J
gem = 9.5, Jvic = 6.6 Hz, OCH2C), 3.35 (m, 1H, H-2), 3.53 (m, 1H, H-5), 3.64 (t, 1H,
3,4 = J4,5 =8.8 Hz, H-4), 3.76 (m, 3H, H-6, H-6’ and OCH2C), 3.80 (s, 3H, MeO), 3.98
(dd, 1H, J2,3 = 10.2 Hz, H-3), 4.78 (d, 1H, J1,2 =8.4 Hz, H-1), 5.69 (d, 1H, J2,NH =8.1 Hz,
NH), 6.86, 7.27 (2d, 4H, J= 8.4 Hz, MeOPh), 7.28–7.37 (m, 5H, Ph).
Anal. Calcd for C53H89NO7 (852.30): C, 74.69; H, 10.53; N, 1.64. Found: C,
74.67; H, 10.49; N, 1.64.
2-(Tetradecyl)hexadecyl (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-galac-
!
topyranosyl)-(1 4)-2-acetamido-6-O-benzyl-2-deoxy-3-O-(4-methoxybenzyl)-b-D-
glucopyranoside (8). To a solution of 6 (193 mg, 0.23 mmol) and 7 (352 mg, 0.35
˚
mmol) in dry CH2Cl2 (10 mL) was added powdered 4 A MS (0.8 g), and the mixture
was stirred for 5 h at room temperature, then cooled to 0°C. Dimethyl(methylthio)-
sulfonium triflate (DMTST, 320 mg, 1.23 mmol) was added to the mixture, and
stirred for 10 h at 0°C. The solids were filtered and washed with CHCl3. The
combined filtrate and washings were again washed with M NaHCO3 and water, dried
(Na2SO4) and concentrated. Column chromatography (90:1 CHCl3–MeOH) of the
residue on silica gel gave 8 (291 mg, 70%) as an amorphous mass: [a]D +9.5° (c 1.6
1
CHCl3); IR (film) 3350, 2950, 1750, 1680, 1520, 700 cmÀ1; H NMR (CDCl3): d 0.88
(t, 6H, J= 7.3 Hz, 2CH3), 1.00–1.41 (m, 53H, 26CH2 and CH), 1.54, 1.78, 1.91, 1.99,
2.16 (5s, 18H, 4AcO, 2AcN), 1.66 (t, 1H, J3ax,4 = Jgem =12.3 Hz, H-3ax), 2.46 (dd, 1H,
J
J
J
J
3eq,4 = 4.5 Hz, H-3eq), 2.94 (dd, 1H, Jgem =8.7, Jvic = 7.3 Hz, OCH2C), 3.56 (dd, 1H,
vic =4.8 Hz, OCH2C), 3.69 (s, 3H, MeO), 3.82 (s, 3H, COOMe), 3.98 (dd, 1H,
0
8,9 = 6.6, Jgem =12.3 Hz, H-9c), 4.23 (dd, 1H, J8,9 =6.8 Hz, H-9 c), 4.43 (d, 1H,
1,2 = 9.1 Hz, H-1a), 4.83 (m, 1H, H-4c), 4.94 (dd, 1H, J2,3 = 10.0, J3,4 =3.2 Hz, H-3b),
0
5.07 (d, 1H, J5,NH =7.5 Hz, NH of c), 5.09 (d, 1H, J1,2 =9.8 Hz, H-1b), 5.23 (dd, 1H,
6,7 = 2.3, J7,8 =9.6 Hz, H-7c), 5.39 (d, 1H, H-4b), 5.48 (t, 1H, H-2b), 5.69 (m, 1H, H-
J
8c), 5.77 (d, 1H, J2,NH =8.4 Hz, NH-a), 6.71, 7.27 (2d, 4H, J=8.4 Hz, MeOPh), 7.25–
8.23 (m, 20H, 4Ph).
Anal. Calcd for C100H138N2O27 (1800.19): C, 66.72; H, 7.73; N, 1.56. Found: C,
66.64; H, 7.45; N, 1.45.

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252
OTSUBO, ISHIDA, AND KISO
2-(Tetradecyl)hexadecyl (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-galac-
!
topyranosyl)-(1 4)-2-acetamido-6-O-benzyl-2-deoxy-b-D-glucopyranoside (9). To
a solution of 8 (512 mg, 0.28 mmol) in CH2Cl2 (7 mL) were added trimethyl-
chlorosilane (TMSCl, 107 mL, 0.84 mmol), SnCl2 (5.2 mg, 27.4 mmol) and anisole (46
mL, 0.42 mmol) at 0°C, and the mixture was stirred for 3 h at 18°C. Once the reaction
was completed, the mixture was extracted with CHCl3. This extract was successively
washed with M NaHCO3 and water, dried (Na2SO4) and concentrated. Column chro-
matography (70:1 CHCl3–MeOH) of the residue on silica gel gave 9 (444 mg, 94%) as
an amorphous mass: [a]D + 38.7° (c 1.7 CHCl3); IR (film) 3550, 3350, 2950, 1750,
1
1680, 1520, 700 cmÀ1; H NMR (CDCl3): d 0.88 (t, 6H, J=6.8 Hz, 2CH3), 1.11–1.40
(m, 53H, 26CH2 and CH), 1.54, 1.76, 1.90, 1.91, 2.03, 2.18 (6s, 18H, 4AcO, 2AcN),
1.62 (t, 1H, J3ax,4 = Jgem = 12.3 Hz, H-3ax), 2.43 (dd, 1H, J3eq,4 =4.6 Hz, H-3eq), 3.20
(dd, 1H, Jgem =9.3, Jvic =6.6 Hz, OCH2C), 3.74 (dd, 1H, Jvic =5.2 Hz, OCH2C), 3.84 (s,
0
3H, COOMe), 3.97 (dd, 1H, J8,9 =6.6, Jgem =12.5 Hz, H-9c), 4.28 (dd, 1H, J8,9 = 6.9
Hz, H-90c), 4.51 (d, 1H, J1,2 =8.2 Hz, H-1a), 4.82 (m, 1H, H-4c), 4.95 (dd, 1H,
J
J
2,3 =10.0, J3,4 = 3.2 Hz, H-3b), 5.04 (d, 1H, J1,2 = 8.1 Hz, H-1b), 5.16 (d, 1H,
5,NH =10.0 Hz, NH-c), 5.22 (dd, 1H, J6,7 = 2.7, J7,8 =9.4 Hz, H-7c), 5.39 (d, 1H, H-4b),
5.44 (d, 1H, J2,NH =8.4 Hz, NH-a), 5.48 (dd, 1H, H-2b), 5.67 (m, 1H, H-8c), 7.14–8.24
(m, 20H, 4Ph).
Anal. Calcd for C92H130N2O26 (1680.04): C, 65.77; H, 7.80; N, 1.67. Found: C,
65.72; H, 7.75; N, 1.42.
2-(Tetradecyl)hexadecyl (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-galac-
!
!
topyranosyl)-(1 4)-[(2,3,4-tri-O-benzyl-a-L-fucopyranosyl)-(1 3)]-2-acetamido-
6-O-benzyl-2-deoxy-b-D-glucopyranoside (11). To a solution of 9 (195 mg, 0.11
˚
mmol) and 10 (90 mg, 0.17 mmol) in dry benzene (5 mL) was added powdered 4 A
MS (0.3 g), and the mixture was stirred for 3 h at room temperature, then cooled to
0°C. NIS (115 mg, 0.51 mmol) and TfOH (7.5 mL, 84.7 mmol) were added to the
mixture and stirred for 2 h at 7°C. The solids were filtered and washed with CHCl3.
The combined filtrate and washings were further washed with M NaHCO3 and M
Na2S2O3, dried (Na2SO4) and concentrated. Column chromatography (80:1 CHCl3–
MeOH) of the residue on silica gel gave 11 (220 mg, 95%) as an amorphous mass:
1
[a]D À 17.9° (c 1.5 CHCl3); IR (film) 3350, 2950, 1750, 1680, 1520, 700 cmÀ1; H
NMR (CDCl3): d 0.88 (t, 6H, J= 6.8 Hz, 2CH3), 1.10 (d, 3H, J5,6 = 6.4 Hz, H-6d),
1.11–1.37 (m, 53H, 26CH2 and CH), 1.57, 1.79, 1.84, 1.92, 2.00, 2.16 (6s, 18H, 4AcO,
2AcN), 1.70 (t, 1H, J3ax,4 = Jgem = 12.4 Hz, H-3ax), 2.43 (dd, 1H, J3eq,4 = 4.4 Hz, H-3eq),
2.77 (dd, 1H, Jgem =9.2, Jvic =6.8 Hz, OCH2C), 3.51 (dd, 1H, Jvic = 5.2 Hz, OCH2C),
3.78 (s, 3H, COOMe), 4.83 (m, 1H, H-4c), 4.92 (dd, 1H, J2,3 = 10.0, J3,4 = 3.6 Hz, H-
3b), 5.03 (d, 1H, J5,NH = 10.5 Hz, NH-c), 5.04 (d, 1H, J1,2 = 8.0 Hz, H-1b), 5.21 (d, 1H,
J
1,2 =3.4 Hz, H-1d), 5.26 (dd, 1H, J6,7 = 2.7, J7,8 =9.4 Hz, H-7c), 5.34 (d, 1H, H-4b),
5.47 (dd, 1H, H-2b), 5.69 (m, 1H, H-8c), 5.93 (d, 1H, J2,NH =8.4 Hz, NH-a), 7.10–8.23
(m, 35H, 7Ph).
Anal. Calcd for C119H158N2O30 (2096.56): C, 68.17; H, 7.60; N, 1.34. Found: C,
67.88; H, 7.40; N, 1.31.

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SIALYL Lex GLYCOLIPID
253
2-(Tetradecyl)hexadecyl (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-galac-
!
!
topyranosyl)-(1 4)-[(2,3,4-tri-O-acetyl-a-L-fucopyranosyl)-(1 3)]-2-acetamido-6-
O-acetyl-2-deoxy-b-D-glucopyranoside (12). A solution of 11 (70 mg, 33.4 mmol) in
EtOH (7 mL) was hydrogenolyzed over Pd(OH)2 (100 mg) for 13 h at 40°C, then
filtered and concentrated. The residue was acetylated with Ac2O (1 mL) and pyridine
(2 mL) for 12 h at room temperature. The solution was diluted with CHCl3, and the
solution was washed with 2 M HCl and water, dried (Na2SO4) and concentrated.
Column chromatography (60:1 CHCl3–MeOH) of the residue on silica gel gave 12 (59
mg, 92%) as an amorphous mass: [a]D À 20.4° (c 1.2 CHCl3); IR (film) 3350, 2950,
1750, 1680, 1520, 700 cm À 1; H NMR (CDCl3): d 0.88 (t, 6H, J= 6.8 Hz, 2CH3), 1.17
1
(d, 3H, J5,6 =6.6 Hz, H-6d), 1.18–1.40 (m, 53H, 26CH2 and CH), 1.57, 1.78, 1.82,
1.90, 1.96, 2.00, 2.02, 2.07, 2.08, 2.14 (10s, 30H, 8AcO, 2AcN), 1.62 (t, 1H,
J
J
3ax,4 = Jgem =12.3 Hz, H-3ax), 2.42 (dd, 1H, J3eq,4 = 4.3 Hz, H-3eq), 2.94 (dd, 1H,
gem = 9.1, Jvic =6.9 Hz, OCH2C), 3.57 (dd, 1H, Jvic = 5.2 Hz, OCH2C), 3.82 (s, 3H,
COOMe), 3.65 (dd, 1H, J5,6 =10.7, J6,7 =2.7 Hz, H-6c), 4.76 (m, 1H, H-4c), 4.85 (d,
1H, J1,2 = 8.4 Hz, H-1b), 5.02 (dd, 1H, J2,3 =10.9, J3,4 =3.9 Hz, H-3b), 5.31 (dd, 1H,
J7,8 = 10.3 Hz, H-7c), 5.44 (dd, 1H, H-2b), 5.47 (d, 1H, H-4b), 5.67 (m, 1H, H-8c),
7.44–8.21 (m, 15H, 3Ph).
Anal. Calcd for C99H142N2O34 (1904.21): C, 62.45; H, 7.52; N, 1.47. Found: C,
62.43; H, 7.29; N, 1.35.
2-(Tetradecyl)hexadecyl (5-acetamido-3,5-dideoxy-D-glycero-a-D-galacto-2-nonulo-
!
!
pyranosylonic acid)-(2 3)-(b-D-galactopyranosyl)-(1 4)-[(a-L-fucopyranosyl)-
!
(1 3)]-2-acetamido-2-deoxy-b-D-glucopyranoside (2). To a solution of 12 (59 mg,
30.9 mmol) in MeOH (4 mL) was added a catalytic amount of NaOMe, and the mixture was
stirred for 18 h at room temperature and then water was added. After completion of the
reaction (15 h), the mixture was neutralized with Amberlite IR-120 (H+) resin and filtered.
The resin was washed with MeOH, and combined filtrate and washings were con-
centrated. Column chromatography (MeOH) of the residue on Sephadex LH-20 (40 g)
1
gave 2 (38 mg, quant.) as an amorphous mass: [a]D À 29.7° (c 0.7 MeOH); H NMR
(CD3OD): d 0.79 (t, 6H, J=6.9 Hz, 2CH3), 1.05 (d, 3H, J5,6 = 6.6 Hz, H-6d), 1.10–1.29
(m, 53H, 26CH2 and CH), 1.62 (t, 1H, J3ax,4 = Jgem =12.4 Hz, H-3ax), 1.84, 1.91 (2s,
6H, 2AcN), 2.78 (dd, 1H, J3eq,4 =3.9 Hz, H-3eq), 3.42 (dd, 1H, J1,2 = 8.0, J2,3 =9.8 Hz,
H-2b), 3.94 (dd, 1H, J3,4 =3.2 Hz, H-3b), 4.28 (d, 1H, J1,2 =7.6 Hz, H-1a), 4.42 (d, 1H,
H-1b), 4.93 (d, 1H, J1,2 = 3.9 Hz, H-1d). FAB-MS spectrum of 2 (negative ion mode,
triethanolamine matrix); m/z: 1239.8 [M-H]À (Calcd for C61H111N2O23, Exact
1239.7578), 1093.8 [M-Fuc], 948.7 [M-NeuAc], 786.7 [948.7-Gal], 640.7 [786.7-Fuc].
ACKNOWLEDGMENTS
This work was supported in part by Grants-in-Aid (No. 12306007) for Scientific
Research from the Ministry of Education, Science, and Culture of Japan, and Japan
Society for Promotion of Science. We are grateful to Sanwa Kagaku Kenkyusho for
FABMS analysis.

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OTSUBO, ISHIDA, AND KISO
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Received October 1, 2001
Accepted February 7, 2002