Synthesis and biological activities of octyl 2,3-di-O-sulfo-α-L- fucopyranosyl-(1 → 3)-2-O-sulfo-α-L-fucopyranosyl-(1 → 4)-2,3-di-O-sulfo-α-L-fucopyranosyl-(1 → 3)-2-O-sulfo-α-L- fucopyranosyl-(1 → 4)-2,3-di-O-sulfo-β-L-fucopyranoside

Article abstract of DOI:10.1016/j.carres.2004.06.006

Octyl 2,3-di-O-sulfo-α-L-fucopyranosyl-(1→3)-2-O-sulfo-α- L-fucopyranosyl-(1→4)-2,3-di-O-sulfo-α-L-fucopyranosyl-(1→3) -2-O-sulfo-α-L-fucopyranosyl-(1→4)-2,3-di-O-sulfo-β-L- fucopyranoside, a fucosyl pentasaccharide with a regular structure resembling the

Full text of DOI:10.1016/j.carres.2004.06.006

Carbohydrate
RESEARCH
Carbohydrate Research 339 (2004) 2083–2090
Synthesis and biological activities of octyl 2,3-di-O-sulfo-a-
fucopyranosyl-(1 fi 3)-2-O-sulfo-a- -fucopyranosyl-(1 fi 4)-2,3-
di-O-sulfo-a- -fucopyranosyl-(1 fi 3)-2-O-sulfo-a-
fucopyranosyl-(1 fi 4)-2,3-di-O-sulfo-b- -fucopyranoside
L
-
L
L
L
-
L
Yuxia Hua,a Yuguo Du,a,* Gangli Yub and Shidong Chub
aResearch Center for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, PR China
bInstitute of Marine Drug and Food, Ocean University of China, Qingdao 266003, China
Received 27 April 2004; accepted 5 June 2004
Available online 7 July 2004
Abstract—Octyl 2,3-di-O-sulfo-a-
L
-fucopyranosyl-(1 fi 3)-2-O-sulfo-a-
L
-fucopyranosyl-(1 fi 4)-2,3-di-O-sulfo-a-
-fucopyranoside, a fucosyl pentasaccharide with a regular structure
L-fucopyranosyl-
(1 fi 3)-2-O-sulfo-a- -fucopyranosyl-(1 fi 4)-2,3-di-O-sulfo-b-
L
L
resembling the repeating unit of a natural sulfated fucan, was chemically synthesized using a convergent ‘2 + 3’ strategy. Regio-
selective 3-O-silylation of b-thiofucopyranoside and AgOTf-catalyzed glycosylation of the protected glycosyl trichloroacetimidate
facilitated a one-pot trisaccharide synthesis. The synthesized target compound showed good antitumor activity in vivo, and
promising anticoagulant activity in vitro.
Ó 2004 Elsevier Ltd. All rights reserved.
Keywords: Regioselective silylation; Fucan; Sulfated oligosaccharide; Antitumor activity; Glycosylation
1. Introduction
groups.3 In terms of biological effects on mammalian
systems, sulfated fucans show anticoagulant activity and
are potent activators of both antithrombin III and
heparin cofactor II.8 They are inhibitors of sperm–egg
interaction,9 and of retroviral infection, blocking the
infection of human cell lines with, for example, HIV,
herpes, and cytomegalovirus.10 They also can act as
anti-angiogenic agents and can block cell–cell binding
mediated by P- or L-Selectin.11 The structural compo-
nents of sulfated fucan necessary for all these biological
activities have not been determined yet. Curious about
the bioactivities of sulfated fucan fragments, we laun-
ched a project on the synthesis of a series of sulfated
fucose-containing oligosaccharides.
Sulfated fucans, which are commonly called fucoidans,
have been isolated mainly from brown algae,1 including
Fucus vesiculosus,2 Sargassum stenophyllum,3 and
Cladosiphon okamuranus.4 Sulfated fucans are among
the most widely studied of all the sulfated polysacchar-
ides of nonmammalian origin that exhibit biological
activities in mammalian systems. These polyanionic
molecules usually have a linear repeating unit, that of
(1 fi 3)-linked b-
L-fucopyranoside that differs by specific
patterns of sulfation.5–7 Recently, sulfated fucans were
also isolated from marine invertebrates and character-
ized.2;3 These animal sulfated fucans consist of (1 fi 3)
and/or (1 fi 4)-linked fucosyl linear backbones that are
partially substituted at C-2 and/or C-4 with sulfate
In our previous report,12 we synthesized octyl 2,3,4-
tri-O-sulfo-a-
fucopyranosyl-(1 fi 3)-2,4-di-O-sulfo-a-
(1 fi 3)-2,4-di-O-sulfo-a- -fucopyranoside, and the cor-
responding bioassay suggested that this oversulfated
L
-fucopyranosyl-(1fi 3)-2,4-di-O-sulfo-a-
L-
L
-fucopyranosyl-
L
* Corresponding author. Tel.: +86-10-62914475; fax: +86-10-629235-
63; e-mail: duyuguo@mail.rcees.ac.cn
0008-6215/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2004.06.006

2084
Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
Me
O
OC8H17
OSO3Na
Me
SEt
OBn
O
HO
O
Me
O
Me
AcO
O
OC8H17
OBn
O
OSO3Na
OSO3Na
Me
O
OH
OBn
AcO
O
4
OBn
OCOCH2Cl
Me
HO
route 1
O
2
OSO3Na
+
O
route 2
Me
Me
SEt
OBn
O
+
O
OSO3Na
OSO3Na
Me
SEt
OBn
O
O
OBn
O
Me
Me
AcO
O
O
OBn
AcO
OSO3Na
OSO3Na
OBn
5
3
OTBS
HO
1
Figure 1. Two proposed strategies for the synthesis of target 1.
tetrasaccharide presented better antitumor activities
than that of its unsulfated counterpart based on
Sarcoma 180 and Lewis lung carcinoma model studies.
In our continuing work on this project, we disclose the
synthesis and biological activities of a natural fucose
pentasaccharide2 having a specific sulfate pattern, that
in CH2Cl2 gave bromide 9 as a mixture, which was di-
rectly used as a donor for the next reaction. Conver-
gently, 6 was silylated with tert-butyldimethylsilyl
chloride (TBSCl) and imidazole in N,N-dimethylfor-
mamide (DMF) at 0 °C to give the 3-O-silylated prod-
uct, which was further acetylated with acetic anhydride
in pyridine, giving 11 in 84% yield. Hydrogen fluoride–
pyridine assisted desilylation of 11 gave acceptor 12 in
an excellent yield (91%). 1HNMR spectrum of 12
showed H-3 and H-4 at d 3.79 ppm (J ¼ 9:3, 3.5 Hz) and
d 5.10 ppm (J ¼ 3:5, 1.0 Hz), respectively, indicating the
correct position for all protecting groups. It should be
noted that tetrabutylammonium fluoride (TBAF)-cata-
lyzed desilylation of 11 gave partial acetyl group mi-
grated byproduct. Glycosylation of bromide 9 and
thioglycoside 12 in CH2Cl2 with promotion by silver
trifluoromethanesulfonate (AgOTf) gave complicated
TLC results. Changing the solvent to ether or toluene,
and adding a small amount of lutidine to the reaction,
did not improve the results. We thought it would be
helpful if we were to use the more stable phosphate 10
instead of unstable 9. Thus, compound 8 was condensed
with dibutyl phosphate in CH2Cl2 at )20 °C, using
N-iodosuccinimide/trimethylsilyl trifluoromethanesulfo-
nate (NIS/TMSOTf) as catalysts, to give an anomeric
phosphate mixture 10. Unfortunately, exhaustive efforts
in the glycosylation of 10 and 12 under various condi-
tions were fruitless.
is, octyl 2,3-di-O-sulfo-a-
sulfo-a- -fucopyranosyl-(1 fi 4)-2,3-di-O-sulfo-a-
pyranosyl-(1 fi 3)-2-O-sulfo-a- -fucopyranosyl-(1 fi 4)-
2,3-di-O-sulfo-b- -fucopyranoside (Fig. 1).
L
-fucopyranosyl-(1 fi 3)-2-O-
L
L
-fuco-
L
L
2. Results and discussion
Retrosynthetic analysis of sulfate pentafucosyl oligo-
saccharide 1 reasonably gave two possible routes toward
the target. In the first route, a (1 fi 3)-linked disacchar-
ide 2 was selected as the basic building block. Coupling
2 with octanol, removal of chloroacetyl (ClAc) from the
4-OH, followed by glycosylation with 2, removing
chloroacetyl again (fi a tetrasaccharide), and a final
step of attaching 313 to the tetrasaccharide would finish
the total synthesis of 1. In the second route, a (1 fi 4)-
linked disaccharide 5 was used as the building block.
Coupling 5 with 4 would give a trisaccharide, which was
desilylated on the 3-OH, and glycosylated with 5 again,
would obtain the backbone of the target 1. In both
routes, benzyl protection groups were planned to mask
intending sulfate positions. As we have already suc-
cessfully synthesized a (1 fi 3)-linked fucosyl tetrasac-
charide, we initially thought route 1 would be familiar to
us.12 To this end (Scheme 1), ethyl 2-O-benzyl-1-thio-b-
Since route 1 was troublesome, we next focused our
attention on route 2 as described in Scheme 2. Com-
pound 11 was glycosylated with 1-octanol under stan-
dard reaction conditions, followed by HF–pyridine
promoted desilylation to afford acceptor 4 in 76% yield
over two steps. To prepare donor 14, 11 was treated
with N-bromosuccinimide (NBS) in (1:9) water–acetone
at rt for 10 min, then transformed into trichloroacetim-
L
-fucopyranoside (6)13 was transformed into 8 in 77%
overall yield via tin complex-assisted 3-O-benzylation
(fi7) and 4-OHchloroacetylation with chloroacetic
anhydride in dry pyridine. Treatment of 8 with bromine

Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
2085
Br
OBn
Me
Me
HO
O
SEt
O
SEt
Me
O
OBn
OBn
c
OBn
e
OH
RO
OBn
6
7 R = H
9
d
OCOCH2Cl
O
8 R = ClAc
a
f
OBu
O
P
OBu
Me
Me
Me
O
SEt
O
SEt
OBn
O
OBn
OBn
10
b
OTBS
OH
12
OBn
OCOCH2Cl
AcO
AcO
11
Me
O
SEt
OBn
g
O
9 + 12
AcO
O
Me
OBn
OBn
OCOCH2Cl
2
h
10 + 12
2
Scheme 1. Reagents and conditions (yields): (a) TBSCl, DMF, Im, 0 °C fi rt, overnight; Ac2O, Pyr, rt, 4 h (84%); (b) HF–Pyr, 0 °C fi rt, overnight
(91%); (c) Bu2SnO, MeOH, reflux; BnBr, TBAI, DMF (89%); (d) ClAc2O, Pyr (87%); (e) Br2, CH2Cl2; (f) Bu2HPO4, NIS, TMSOTf (90%);
(g) AgOTf, CH2Cl2; (h) TMSOTf, CH2Cl2.
Me
Me
OC8H17
OBn
O
SEt
OBn
O
a
Me
b
OC8H17
OBn
O
OTBS
C8H17OH
OTBS
AcO
AcO
OH
4
13
11
AcO
c
Me
OC8H17
OBn
O
Me
SEt
OBn
O
O
AcO
I
I
Me
OC(NH)CCl3
OBn
O
OBn
Me
O
O
+ 4
OBn
OTBS
+ 7
d
AcO
Me
II
O
OBn
b
O
II
a
Me
OBn
14
15 R = TBS
16 R = H
OTBS
O
AcO
5
OBn
OR
III
AcO
Me
I
OC8H17
OR2
O
OR1
O
Me
II
O
OR2
OR2
a
O
5 + 16
17 R1 = Ac, R2 = Bn, R3 = TBS
18 R1 = Ac, R2 = Bn, R3 = H
Me
III
O
b
e
OR2
O
19 R1 = R3 = Ac, R2 = Bn
20 R1 = R3 = Ac, R2 = H
OR1
O
f
g
Me
IV
OR2
-
21 R1 = R3 = Ac, R2 = OSO3 Na+
OR2
h
O
-
1 R1 = R3 = H, R2 = OSO3 Na+
Me
V
O
OR2
OR1 OR3
Scheme 2. Reagents and conditions (yields): (a) NIS, TMSOTf, CH2Cl2, )20 °C (90% for 13; 62% for 15; 75% for 17); (b) HF–Pyr (84% for 4; 74%
for 16); (c) NBS, 1:9 H2O–acetone; Cl3CCN, DBU, CH2Cl2 (85%); (d) AgOTf, Et2O, 0 °C, 50 min (82%); (e) Ac2O, Pyr (79% from 17 to 19); (f) Pd–C,
H2, 1:1 MeOH–EtOAc, 80%; (g) SO3ÁPyr, Pyr, 55 °C; 3 N NaOH; (h) NaOMe, MeOH (60% from 20).

2086
Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
idate with trichloroacetonitrile and 1,8-di-azabicyclo-
[5.4.0]undec-7-ene (DBU) in dry methylene chloride,
affording the product in 85% yield over two steps.
AgOTf-catalyzed glycosylation14 of 14 and 7 in dry
ether gave an excellent yield of disaccharide 5 (82%
isolated yield), which could be directly used as a donor
to react with 4 in the presence of NIS/TMSOTf in a one-
fation using convergent ‘2 + 3’ strategy. Regioselective 3-
O-silylation of b-thiofucoside and AgOTf-promoted
glycosylation using a Schmidt donor facilitated a one-
pot trisaccharide preparation. The synthesized target
compound 1 showed good antitumor activity in vivo,
and promising anticoagulant activity in vitro.
1
pot reaction, affording trisaccharide 15 (62%). H–1H
COSY of 5 showed a doublet (J ¼ 3:4 Hz) at d 5.03 ppm,
while two characteristic a H-1s of 15 appeared at d
4.80 ppm (J ¼ 3:4 Hz) and d 4.97 ppm (J ¼ 3:5 ppm),
respectively, confirming the a-linkage between sugar
residues. Interestingly, TMSOTf-catalyzed the same
reaction in CH2Cl2 gave much lower yield due to the
quick decomposition of 14. To avoid acetyl migration
during desilylation on C-3, 15 was treated with
HF–pyridine giving the trisaccharide acceptor 16 in a
yield of 74%. Condensation of 5 and 16 as described in
the preparation of 15 furnished pentasaccharide 17 in
75% yield. Removal of the TBS group from 17 with
HF–pyridine (fi18), followed by acetylation with
Ac2O in pyridine (fi19), hydrogenolysis with H2 on
Pd(OH)2 (fi20), sulfation with sulfur trioxideÁpyridine
complex in pyridine at 55 °C (fi21), and the final
deacetylation with NaOMe in MeOHcomplete the
synthesis of target compound 1. HMQC spectra
assigned five anomeric protons at d 4.29 ppm (J ¼
7:8 Hz), 4.94 ppm (J ¼ 3:3 Hz), 5.21 ppm (J ¼ 3:3 Hz),
5.29 ppm (J ¼ 3:2 Hz) and 5.31 ppm (J ¼ 3:1 Hz),
respectively, supporting the structure of compound 1.
After desalting on an AKTA–FPLC chromatography
system, compound 1 was directly used for the following
bioassays.
The antitumor activity of 1 was preliminarily tested in
vivo according to the method described by Sasaki and
Takasuka.15 Kun-min mice weighing about 20 g and
Sarcoma-180 cells (5 · 106) were used for the bioassay.
Cisplatinꢀ (CDDP) was selected as the positive control
in the parallel tests. The mice were injected with com-
pound 1 (daily dose, 1 mg/kg each; i.v.) from day 3 to 14
after inoculation with the tumor cells, while CDDP was
given every other day. Control mice were injected with
saline alone. The tumor inhibition ratios for 1 and
CDDP on S180 were 45% and 65%, respectively. The
anti-Xa activity of compound 1 was also measured
according to the standard method,16 and it inhibited
factor Xa at IC50 ¼ 60 lM (or Ki ¼ 33 lM) based on the
protease inhibition model in vitro. Preliminary testing of
the cytotoxicity of compound 1 was carried out using a
procedure described by Connolly et al.17 Compound 1
showed no activity towards human hepatocellular car-
cinoma BEL-7402 cells. It is thus deduced that sulfated
fucose oligomers might enhance the antitumor activities
by acting as immunostimulants in vivo.
3. Experimental
3.1. General
Optical rotations were determined at 25 °C with a Per-
kin–Elmer Model 241-Mc automatic polarimeter at the
sodium D-line. 1H, 13C, 1H–1HCOSY, and HMQC
NMR spectra were recorded with ARX 400 spectro-
meters for solutions in CDCl3 or D2O. Chemical shifts
are given in ppm downfield from internal Me4Si. Mass
spectra were measured using MALTITOF-MS with
dihydroxybenzoic acid (DHB) as matrix. Thin-layer
chromatography (TLC) was performed on silica gel
HF254 with detection by charring with 30% (v/v) H2SO4
in MeOHor in some cases by a UV lamp.
3.2. Ethyl 2,3-di-O-benzyl-1-thio-b-L-fucopyranoside (7)
Compound 6 (2.44 g, 8.20 mmol) and dibutyltin oxide
(2.25 g, 8.86 mmol) were pre-dried in one flask under
vacuum for 3 h, then dissolved in MeOH(35 mL). The
mixture was stirred under reflux for 3 h, concentrated to
dryness, then suspended in toluene (80 mL). To the
above mixture was added benzyl bromide (1.05 mL,
8.81 mmol) and Bu4NI (3.04 g, 8.20 mmol). The reaction
was carried out at 60 °C for 24 h, at the end of which
time TLC (3:1 petroleum ether–EtOAc) indicated that
the reaction was complete. Concentration of the reac-
tion mixture, and purification of the residue by column
chromatography (4:1 petroleum ether–EtOAc) gave
syrupy 7 (2.82 g, 89%).13
3.3. Ethyl 2,3-di-O-benzyl-4-O-chloroacetyl-1-thio-b-L-
fucopyranoside (8)
To a solution of 7 (1.16 g, 2.99 mmol) in pyridine (5 mL)
was added chloroacetic anhydride (714 mg, 3.80 mmol).
The mixture was stirred at rt for 6 h, and then co-
evaporated with toluene to dryness. The residue was
purified by silica gel column chromatography (9:1
petroleum ether–EtOAc), affording 8 (1.21 g, 87%) as a
25
D
syrup: ½aŠ )21 (c 1, CHCl3); 1HNMR (400 MHz,
CDCl3): 1.24 (d, 3H, J 6.4 Hz, H-6), 1.31 (t, 3H, J
7.2 Hz, CH3), 2.71–2.79 (m, 2H, SCH2), 3.55 (t, 1H, J
9.6 Hz, H-2), 3.64 (dd, 1H, J 3.3, 9.6 Hz, H-3), 3.70 (dq,
1H, J 6.4, 1.0 Hz, H-5), 4.20 (s, 2H, ClCH2CO), 4.45 (d,
1H, J 9.6 Hz, H-1), 4.54, 4.72, 4.74, 4.82 (4 d, 4H, J
In conclusion, we have successfully synthesized a
fucosyl pentasaccharide having specific pattern of sul-

Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
2087
10.1 Hz, PhCH2), 5.43 (dd, 1H, J 3.3, 1.0 Hz, H-4), 7.25–
7.40 (m, 10H, Ph). Anal. Calcd for C24H29ClO5S: C,
61.99; H, 6.29. Found: C, 62.27; H, 6.32.
poured into aq NaHCO3 (100 mL), and extracted with
EtOAc (3 · 80 mL). The combined EtOAc extracts were
sequentially washed with 5% aq HCl (3 · 200 mL), aq
NaHCO3 (3 · 200 mL), brine (3 · 200 mL), and then
dried over anhyd Na2SO4 and concentrated. The crude
product was subjected to column chromatography with
3.4. Dibutyl 2,3-di-O-benzyl-4-O-chloroacetyl-b-L-fuco-
pyranosyl 1-phosphate (10)
3:1 petroleum ether–EtOAc as eluent, giving 12 as a
25
D
To a cooled ()20 °C) solution of compound 8 (1.05 g,
2.26 mmol) and dibutyl phosphate (470 lL, 2.52 mmol)
in dry CH2Cl2 (10 mL) was added N-iodosuccinimide
(830 mg, 3.39 mmol) and TMSOTf (41 lL, 0.23 mmol).
The mixture was stirred for 30 min under an N2 atmo-
sphere, quenched by Et3N (two drops), and concen-
trated. The residue was purified by silica gel column
chromatography (3:1 petroleum ether–EtOAc) to give
syrupy 10 as an a,b mixture (1.24 g, 90%); Selected peaks
white solid (1.10 g, 91%): ½aŠ )23 (c 1, CHCl3); 1H
NMR (400 MHz, CDCl3): d 1.20 (d, 3H, J 6.6 Hz, H-6),
1.33 (t, 3H, J 7.4 Hz, CH3CH2S), 2.16 (s, 3H, CH3CO),
2.77 (m, 2H, CH3CH2S), 3.48 (t, 1H, J 9.5 Hz, H-2),
3.68 (dq, 1H, J 6.6, 1.0 Hz, H-5), 3.79 (dd, 1H, J 9.3,
3.5 Hz, H-3), 4.45 (d, 1H, J 9.5 Hz, H-1), 4.72, 4.83 (2 d,
2 · 1H, J 10.2 Hz, PhCH2), 5.10 (dd, 1H, J 3.5,1.0 Hz,
H-4), 7.35 (m, 5H, Ph). Anal. Calcd for C17H24O5S: C,
59.98; H, 7.11. Found: C, 59.78; H, 7.20.
1
for the b isomer: HNMR (400 MHz, CDCl 3): d 0.85,
0.92 (2t, 6H, J 7.4 Hz, 2 CH3), 1.17 (d, 3H, J 6.5 Hz, H-
6), 1.23–1.68 (m, 8H), 3.79–3.82 (m, 1H), 3.92–4.05 (m,
5H), 4.15 (s, 2H, ClCH2CO), 4.26 (q, 1H, J 6.5 Hz),
4.58, 4.72 (2 d, 2H, J 11.5 Hz), 4.74 (s, 2H), 5.45 (dd,
1H, J 1.0, 3.2 Hz), 5.83 (dd, 1H, J 3.5, 6.7 Hz), 7.25–7.34
(m, 10H). Anal. Calcd for C30H42ClO9P: C, 58.77; H,
6.91. Found: C, 58.91; H, 6.83.
3.7. Octyl 4-O-acetyl-2-O-benzyl-3-O-tert-butyldimethyl-
silyl-b-L-fucopyranoside (13)
To a solution of compound 11 (1.51 g, 3.33 mmol) and
1-octanol (800 lL, 5.04 mmol) in dry CH2Cl2 (10 mL)
ꢀ
was added 4 A molecular sieves (1 g). The mixture was
stirred at )20 °C for 20 min under an N2 atmosphere,
then N-iodosuccinimide (1.223 g, 4.99 mmol) and
TMSOTf (50 lL, 0.28 mmol) were added. The mixture
was stirred under these conditions for another 30 min,
quenched by Et3N (two drops), and concentrated. The
residue was purified by silica gel column chromatogra-
phy (10:1 petroleum ether–EtOAc) to give 13 as a white
3.5. Ethyl 4-O-acetyl-2-O-benzyl-3-O-tert-butyldimethyl-
silyl-1-thio-b-L-fucopyranoside (11)
To a mixture of compound 6 (1.41 g, 4.73 mmol) in N,N-
dimethylformamide (10 mL) was added imidazole
(0.90 g, 11.22 mmol) and TBSCl (1.01 g, 5.70 mmol) at
0 °C. The mixture was stirred under these conditions for
30 min, then overnight at room temperature. The reac-
tion mixture was diluted with water (100 mL) and ex-
tracted with EtOAc (3 · 100 mL). The organic phase was
dried over anhyd MgSO4 and concentrated. Purification
of the residue by column chromatography (8:1 petro-
25
1
foam (1.56 g, 90%): ½aŠ )48 (c 1, CHCl3); HNMR
D
(400 MHz, CDCl3): d 0.02, 0.08 (2 s, 2 · 3H, Si(CH3)2),
0.86 (s, 9H, SiC(CH3)3), 0.84–0.90 (m, 12H, SiC(CH3)3,
CH3C7H14O), 1.22 (d, 3H, J 6.6 Hz, H-6), 1.32–1.63 (m,
12H, OCH2C6H12CH3), 2.14 (s, 3H, CH3CO), 3.40–3.50
(m, 2H, H-2 and one proton of OCH2), 3.65 (dq, 1H, J
6.6, 1.0 Hz, H-5), 3.71 (dd, 1H, J 9.4, 3.7 Hz, H-3), 3.91–
3.97 (m, 1H, one proton of OCH2), 4.34 (d, 1H, J
7.8 Hz, H-1), 4.55, 4.55 (2 d, 2 · 1H, J 10.8 Hz, PhCH2),
5.10 (dd, 1H, J 3.7, 1.0 Hz, H-4), 7.29–7.37 (m, 5H, Ph).
Anal. Calcd for C29H50O6Si: C, 66.63; H, 9.64. Found:
C, 66.71; H, 9.69.
leum ether–EtOAc), followed by acetylation with Ac2O
25
in pyridine, afforded 11 (1.81 g, 84%) as a syrup: ½aŠ
D
1
)25 (c 1, CHCl3); HNMR (400 MHz, CDCl 3): d 0.04,
0.08 (2 s, 2 · 3H, Si(CH3)2), 0.88 (s, 9H, SiC(CH3)3), 1.18
(d, 3H, J 6.6 Hz, H-6), 1.31 (t, 3H, J 7.6 Hz, CH3CH2S),
2.16 (s, 3H, CH3CO), 2.70–2.81 (m, 2H, CH3CH2S),
3.48 (t, 1H, J 9.3 Hz, H-2), 3.66 (q, 1H, J 6.6 Hz, H-5),
3.76 (dd, 1H, J 9.3, 3.5 Hz, H-3), 4.45 (d, 1H, J 9.3 Hz,
H-1), 4.72, 4.83 (2 d, 2 · 1H, J 10.2 Hz, PhCH2), 5.10 (d,
1H, J 3.5 Hz, H-4), 7.28–7.45 (m, 5H, Ph). Anal. Calcd
for C23H38O5SSi: C, 60.75; H, 8.42. Found: C, 60.82; H,
8.33.
3.8. Octyl 4-O-acetyl-2-O-benzyl-b-L-fucopyranoside (4)
Removal of the TBS group from compound 13 (1.31 g,
2.51 mmol) as described in the preparation of 12 gave 4
as a white solid (860 mg, 84%): ½aŠ25 )35 (c 1, CHCl3); 1H
D
NMR (400 MHz, CDCl3) d 0.87 (t, 3H, J 7.0 Hz,
CH3C7H14O), 1.21 (d, 3H, J 6.6 Hz, H-6), 1.29–1.69 (m,
12H, OCH2C6H12CH3), 2.14 (s, 3H, CH3CO), 3.46–3.53
(m, 2H, H-2 and one proton of OCH2), 3.67 (dq, 1H, J
6.6 Hz, H-5), 3.75 (dd, 1H, J 9.7, 3.2 Hz, H-3), 3.94–3.98
(m, 1H, one proton of OCH2), 4.37 (d, 1H, J 7.8 Hz, H-
1), 4.81, 5.01 (2 d, 2 · 1H, J 11.2 Hz, PhCH2), 5.18 (d,
3.6. Ethyl 4-O-acetyl-2-O-benzyl-1-thio-b-L-fucopyrano-
side (12)
To a solution of 11 (1.62 g, 3.57 mmol) in pyridine
(40 mL) was added HF–Pyridine (5 mL) at 0 °C. The
mixture was stirred at room temperature overnight,

2088
Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
1H, J 3.2 Hz, H-4), 7.29–7.35 (m, 5H, Ph). Anal. Calcd
for C23H36O6: C, 67.62; H, 8.88. Found: C, 67.47; H,
8.94.
1 H ,J 2.7 Hz, H-4II), 7.25–7.40 (m, 15H, Ph). Anal.
Calcd for C43H60O9SSi: C, 66.12; H, 7.74. Found: C,
66.40; H, 7.63.
3.11. Octyl 4-O-acetyl-2-O-benzyl-3-O-tert-butyldimethyl-
L
3.9. 4-O-Acetyl-2-O-benzyl-3-O-tert-butyldimethylsilyl-
b-L-fucopyranosyl trichloroacetimidate (14)
silyl-a-
-fucopyranosyl-(1 fi 4)-2,3-di-O-benzyl-a-
L
-fuco-
L-fucopyrano-
pyranosyl-(1 fi 3)-4-O-acetyl-2-O-benzyl-b-
side (15)
To a solution of compound 11 (775 mg, 1.71 mmol) in
(1:9) H2O–CH3COCH3 (40 mL) was added N-bromo-
succinimide (610 mg, 3.42 mmol) at 0 °C. The mixture
was vigorously stirred under these conditions for 10 min,
then diluted with CH2Cl2 and washed with aq NaHCO3
(3 · 100 mL). The organic phase was dried over anhyd
Na2SO4 and concentrated under diminished pressure
giving a white residue(670 mg). To a solution of the
above residue in dry CH2Cl2 (5 mL) was added CCl3CN
(490 lL, 4.89 mmol) and DBU (75 lL, 0.50 mmol) under
an N2 atmosphere, and the mixture was then stirred for
3 h under these conditions. Concentration of the reac-
tion mixture and purification of the residue by column
To a mixture of 4 (373 mg, 0.91 mmol) and 5 (709 mg,
ꢀ
0.91 mmol) in dry CH2Cl2 (5 mL) was added 4 A
molecular sieves (1 g). The mixture was stirred at )20 °C
under an N2 atmosphere for 20 min, then NIS (370 mg,
1.51 mmol) and TMSOTf (19.4 lL, 0.11 mmol) were
added. The reaction mixture was stirred under these
conditions for 30 min, quenched by Et3N (two drops),
and concentrated. The residue was purified by silica gel
column chromatography (10:1 petroleum ether–EtOAc)
25
D
to give 15 (639 mg, 62%) as white foam: ½aŠ )109 (c 0.7,
1
CHCl3); HNMR (400 MHz, CDCl 3): d 0.04, 0.06 (2 s,
2 · 3H, Si(CH3)2), 0.77 (d, 1H, J 6.5 Hz, H-6II), 0.84 (s,
9H, SiC(CH3)3), 0.86 (s, 3H, CH3), 0.94 (d, 3H, J 6.5 Hz,
H-6I), 1.19 (d, 3H, J 6.5 Hz, H-6III), 1.23–1.66 (m, 12H,
OCH2C6H12CH3), 1.95, 2.10 (2 s, 2 · 3H, CH3CO), 3.43
(br s, 1H, H-3II), 3.50 (q, 1H, J 7.0 Hz, OCH2), 3.52 (dd,
1H, J 7.7 Hz, H-2I), 3.56–3.62 (m, 2H, one proton of
chromatography (6:1 petroleum ether–EtOAc) gave 14
25
D
(810 mg, 85% over two steps) as a syrup: ½aŠ )34 (c 1,
1
CHCl3); HNMR (400 MHz, CDCl 3): d. 01, 0.08 (2 s,
2 · 3H, Si(CH3)2), 0.86 (s, 9H, SiC(CH3)3), 2.15 (s, 3H,
CH3CO), 3.75 (t, 1H, J 7.8 Hz, H-2), 3.83–3.88 (m, 2H,
H-3, H-5), 4.73, 4.92 (2 d, 2 · 1H, J 10.8 Hz, PhCH2),
5.12 (d, 1H, J 2.4 Hz, H-4), 5.77 (d, 1H, J 7.8 Hz, H-1),
7.25–7.35 (m, 5H, Ph), 8.64 (s, 1H, NH). MALDITOF-
MS: Calcd for C23H34Cl3NO6Si, m=z 553; found: m=z
576 (M+Na)þ.
II
OCH2H-5II), 3.79 (br s, H-2II, H -4), 3.81 (dd, 1H, J
9.9, 3.4 Hz, H-3III), 3.93–3.98 (m, 2H, H-3I and H-5I),
4.06 (dd, 1H, J 9.9, 3.4 Hz, H-2III), 4.26 (q, 1H, J 6.7 Hz,
H-5III), 4.35 (d, 1H, J 7.7 Hz, H-1I), 4.80 (d, 1H, J
3.4 Hz, H-1III), 4.47, 4.57, 4.64, 4.66, 4.67, 4.68, 4.70,
4.73 (8 d, 8 · 1H, J 10.8 Hz, PhCH2), 4.97 (d, 1H, J
3.5 Hz, H-1II), 5.11 (br s, 1H, H-4I), 5.31 (d, 1H, J
3.4 Hz, H-4III), 7.12–7.40 (m, 20H, Ph). Anal. Calcd for
C64H90O15Si: C, 68.18; H, 8.05. Found: C, 68.29; H,
7.98.
3.10. Ethyl 4-O-acetyl-2-O-benzyl-3-O-tert-butyldimethyl-
silyl-a-
L
-fucopyranosyl-(1 fi 4)-2,3-di-O-benzyl-1-thio-b-
L
-fucopyranoside (5)
To a solution of 7 (500 mg, 1.29 mmol) and 14 (786 mg,
ꢀ
1.42 mmol) in dry Et2O (5 mL) was added 4 A molecular
3.12. Octyl 4-O-acetyl-2-O-benzyl-a-
(1 fi 4)-2,3-di-O-benzyl-a- -fucopyranosyl-(1 fi 3)-2-O-
benzyl-4-O-acetyl-b- -fucopyranoside (16)
L-fucopyranosyl-
sieves (1 g) at 0 °C under an N2 atmosphere. The mixture
was stirred in a dark room for 20 min, then AgOTf
(313 mg, 1.42 mmol) was added. The reaction mixture
was stirred under these conditions for 30 min, quenched
by Et3N (one drop), and concentrated. The residue was
purified by silica gel column chromatography (15:1
L
L
Removal of the TBS group from compound 15 (380 mg,
0.34 mmol) as described in the preparation of 12 gave 16
25
D
1
(251 mg, 74%) as a syrup: ½aŠ )131 (c 1.2, CHCl3); H
petroleum ether–EtOAc) giving 5 (824 mg, 82%) as a
NMR (400 MHz, CDCl3): 0.75 (d, 3H, J 6.5 Hz, H-6II),
0.85 (t, 3H, J 7.0 Hz, OC7H14CH3), 0.93 (d, 3H, J
6.5 Hz, H-6I), 1.19 (d, 3H, J 6.5 Hz, H-6III), 1.32–1.67
(m, 12H, OCH2C6H12CH3), 1.97, 2.10 (2 s, 2 · 3H,
CH3CO), 3.43 (br s, 1H, H-3II), 3.48–3.55 (m, 1H,
OCH2), 3.57 (dd, 1H, J 8.0, 9.7 Hz, H-2I), 3.62–3.67 (m,
25
D
white foam: ½aŠ )59 (c 2, CHCl3); 1HNMR (400 MHz,
CDCl3): d 0.04, 0.11 (2 s, 2 · 3H, Si(CH3)2), 0.85 (s, 9H,
SiC(CH3)3), 0.88, 0.92 (2 d, 2 · 3H, J 6.6 Hz, H-6I, H -
6II), 1.28 (t, 3H, J 7.6 Hz, CH3CH2S), 2.14 (s, 3H,
CH3CO), 2.60–2.82 (m, 2H, CH3CH2S), 3.45 (dd, 1H, J
9.7, 2.7 Hz, H-3II), 3.49 (q, 1H, J 6.6 Hz, H-5I), 3.68 (dd,
1H, J 9.3, 3.5 Hz, H-3I), 3.71 (t, 1H, J 9.3 Hz, H-2I), 3.78
(d, 1H, J 2.3 Hz, H-4I), 4.21 (dd, 1H, J 9.7, 3.4 Hz, H-
2II), 4.31 (d, 1H, J 9.3 Hz, H-1I), 4.47 (q, 1H, J 6.6 Hz,
H-5II), 4.63, 4.71, 4.74, 4.76, 4.84, 4.91 (6 d, 6 · 1H, J
10.4 Hz, PhCH2), 5.03 (d, 1 H, J 3.4 Hz, H-1II), 5.10 (d,
II
2H, OCH2C7H15, H -5 ), 3.75 (dd, 1H, J 10.3, 3.2 Hz, H-
3III), 3.79 (br s, 2H, H-2II, H -4 ), 3.93–3.99 (m, 2H, H-
II
3I, H -5), 4.03 (dd, 1H, J 10.3, 3.4 Hz, H-2III), 4.28 (q,
I
1H, J 6.6 Hz, H-5III), 4.35 (d, 1H, J 7.8 Hz, H-1I), 4.86
(d, 1H, J 3.4 Hz, H-1III), 4.39, 4.54, 4.61, 4.67, 4.70, 4.71,
4.73, 4.90 (8 d, 8 · 1H, J 10.7 Hz, PhCH2), 5.06 (d, 1H, J

Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
2089
2.2 Hz, H-4I), 5.08 (s, 1H, H-1II), 5.28 (d, 1H, J 3.2 Hz,
H-4III), 7.12–7.40 (m, 20H, Ph). Anal. Calcd for
C58H76O15: C, 68.75; H, 7.56. Found: C, 68.49; H, 7.66.
(d, 1H, J 3.5 Hz, H-1III), 4.79 (d, 1H, J 4.4 Hz, H-1IV),
4.89 (d, 1H, J 10.9 Hz, PhCH2), 5.11 (d, 1H, J 3.1 Hz,
H-1II), 5.17–5.5.22 (m, 3H, H-4I, H -4 , H -1 ), 5.29 (dd,
1H, J 9.4, 1.9 Hz, H-3V), 5.30 (d, 1H, J 1.9 Hz, H-4V),
7.18–7.45 (m, 35H, Ph). MALDITOF-MS: Calcd for
C95H118O25, m=z 1658.8; found: m=z 1680.5 (M+Na)þ,
1696.5 (M+K)þ.
III
V
3.13. Octyl 4-O-acetyl-2-O-benzyl-3-O-tert-butyldimethyl-
silyl-a-
pyranosyl-(1fi 3)-4-O-acetyl-2-O-benzyl-a-
yl-(1 fi 4)-2,3-di-O-benzyl-a- -fucopyranosyl-(1 fi 3)-4-
O-acetyl-2-O-benzyl-b- -fucopyranoside (17)
L
-fucopyranosyl-(1 fi 4)-2,3-di-O-benzyl-a-
L-fuco-
-fucopyranos-
L
L
L
3.15. Octyl 3,4-di-O-acetyl-a-
L
-fucopyranosyl-(1 fi 4)-a-
-fucopyranosyl-
-fucopyranosyl-(1 fi 3)-4-O-acetyl-b- -fuco-
L
-fucopyranosyl-(1 fi 3)-4-O-acetyl-a-
L
Coupling of 5 (170 mg, 0.23 mmol) and 16 (200 mg,
0.20 mmol) as described in the preparation of 15 gave 17
(1 fi 4)-a-
L
L
pyranoside (20)
25
(260 mg, 75%) as a white foam; ½aŠ )37 (c 0.8, CHCl3);
D
1HNMR (400 MHz, CDCl 3): d 0.04, 0.08 (2 s, 2 · 3H,
Si(CH3)2), 0.73 (d, 3H, J 6.5 Hz, H-6II), 0.77 (d, 3H, J
6.6 Hz, H-6IV), 0.84–0.87 (m, 12H, CH3SiC(CH3)3), 0.93
(d, 3H, J 6.6 Hz, H-6I), 1.13 (d, 3H, J 6.5 Hz, H-6V),
1.19 (d, 3H, J 6.5 Hz, H-6III), 1.23–1.63 (m, 12H,
OCH2C6H12CH3), 1.88, 1.90, 2.10 (3 s, 3 · 3H, CH3CO),
3.43 (d, 1H, H-3II), 3.48–3.51 (m, 2H, H-3IV and OCH2),
3.57 (dd, 1H, J 7.8, 9.7 Hz, H-2I), 3.62–3.66 (m, 2H, H-
To a solution of compound 19 (152 mg, 0.09 mmol) in
1:1 MeOH–EtOAc (30 mL) was added 20% Pd(OH)2-
on-charcoal (70 mg, 0.05 mmol). The mixture was bub-
bled with H2 at a flow rate of 100 mL/min for 70 h. The
reaction mixture was filtered, and the filtrate was con-
centrated to give 20 (75 mg, 80%) as a white foam: ½aŠ
25
D
1
)57 (c 0.8, H2O); HNMR (400 MHz, CD 3OD): d 0.88
(t, 3H, J 7.1 Hz, OC7H14CH3), 1.01, 1.04, 1.13, 1.16,
1.28 (5 d, 5 · 3H, J 6.5 Hz, 5 H-6), 1.27–1.64 (m, 12H,
OCH2C6H12CH3), 1.97, 2.10, 2.12 (3 s, 4 · 3H,
4CH3CO), 3.51–3.92 (m, 11H), 4.05 (dd, 1H, J 3.3,
10.4 Hz, H-2V), 4.08 (q, J 9.4 Hz, H-5), 4.28 (d, 1H, J
8.0 Hz, H-1I), 4.36 (q, 1H, J 6.6 Hz, H-5), 4.68 (q, 1H, J
6.6 Hz, H-5), 4.81 (q, 1H, J 6.6 Hz, H-5), 4.91 (d, 1H, J
4.0 Hz, H-1), 4.93 (d, 1H, J 3.8 Hz, H-1), 4.98 (d, 1H, J
4.0 Hz, H-1), 5.01 (d, 1H, J 3.8 Hz, H-1), 5.15 (dd, 1H, J
3.3, 10.4 Hz), 5.21, 5.28, 5.33 (3 d, 3 · 1H, J 3.3 Hz, 3 H-
4). MALDITOF-MS: Calcd for C46H76O25, m=z 1028;
found: m=z 1051.3 (M+Na)þ.
III
IV
3III, OCH2), 3.73–3.97 (m, 10H, H-2II, H -2 , H -2 , H -
II
IV
I
II
IV
3V, H -5 , H -5 , H -5, H -4 , H -4 ), 4.11 (dd, 1H, J 3.5,
9.7 Hz, H-3I), 4.18 (dd, 1H, J 3.0, 9.8 Hz, H-3III), 4.21
(q, 1H, J 6.6 Hz, H-5V), 4.31 (q, 1H, J 6.7 Hz, H-5III),
4.35 (d, 1H, J 7.8 Hz, H-1I), 4.41–4.74 (m, 13H, PhCH2),
4.80 (d, 1H, J 3.5 Hz, H-1III), 4.83 (d, 1H, J 3.3 Hz, H-
1V), 4.89 (d, 1H, J 10.5 Hz, PhCH2), 4.99 (br d, 1H, J
3.5 Hz, H-4I), 5.11 (d, 1H, J 2.7 Hz, H-1II), 5.20 (d, 1H,
J 3.4 Hz, H-1IV), 5.24 (br d, 1H, J 2.3 Hz, H-4III), 5.30
(d, 1H, J 3.4 Hz, H-4V), 7.15-7.40 (m, 35H, Ph). Anal.
Calcd for C99H130O24Si: C, 68.65; H, 7.56. Found: C,
68.89; H, 7.61.
3.16. Octyl 3,4-di-O-acetyl-2-O-sulfo-a-
(1 fi 4)-2,3-di-O-sulfo-a- -fucopyranosyl-(1 fi 3)-4-O-
acetyl-2-O-sulfo-a- -fucopyranosyl-(1 fi 4)-2,3-di-O-sul-
fo-a- -fucopyranosyl-(1 fi 3)-4-O-acetyl-2-O-sulfo-b-
fucopyranoside (1)
L-fucopyranosyl-
3.14. Octyl 3,4-di-O-acetyl-2-O-benzyl-a-
yl-(1 fi 4)-2,3-di-O-benzyl-a- -fucopyranosyl-(1 fi 3)-4-
O-acetyl-2-O-benzyl-a- -fucopyranosyl-(1 fi 4)-2,3-di-O-
benzyl-a- -fucopyranosyl-(1 fi 3)-4-O-acetyl-2-O-benzyl-
b- -fucopyranoside (19)
L
-fucopyranos-
L
L
L
L
L
L-
L
L
To a solution of compound 20 (65 mg, 0.06 mmol) in
pyridine (4 mL) was added sulfur trioxideÁpyridine
complex (322 mg, 1.98 mmol). The mixture was stirred at
55 °C for 72 h, then cooled to 4 °C to generate a pre-
cipitate that was filtered and dissolved in water (1 mL).
Aq. 3 N NaOHwas added to the mixture until pH10.
The water phase was washed with CH2Cl2 (2 · 10 mL),
then loaded onto a Sephadex LH-20 column and eluted
with water. The desired fractions were combined and
freeze dried to give 21, which was directly dissolved into
ammonia-saturated MeOH(50 mL). The mixture was
stirred at room temperature for 3 days, and concen-
trated to dryness. To remove the salt in the mixture, the
residue was dissolved in water (1 mL) and passed
through a 0.22-lm syringe filter. The filtrate was loaded
on a Superdex-8482 column (XK16/60 cm, Amersham
Biosciences, Sweden) and eluted with doubly deionized
Removal of the TBS group from compound 17 (220 mg,
0.13 mmol) as described in the preparation of 4 gave
syrupy 18 (180 mg), which was acetylated with Ac2O
(2 mL) in pyridine (4 mL), gave 19 (166 mg, 79% for two
25
1
steps) as a syrup: ½aŠ )18 (c 0.8, CHCl3); HNMR
D
(400 MHz, CDCl3): d 0.72 (d, 6H, J 6.5 Hz, 2 H-6), 0.85
(t, 3H, OC7H14CH3), 0.96, 1.13, 1.19 (3 d, 3 · 3H, J
6.5 Hz, 3 H-6), 1.32–1.67 (m, 12H, OCH2C6H12CH3),
1.85, 1.90, 1.96, 2.08 (4 s, 4 · 3H, 4 CH3CO), 3.43 (d,
1H, J 2.3 Hz, H-3II), 3.51–3.55 (m, 2H, H-3IV, one
proton of OCH2), 3.57 (dd, 1H, J 7.6, 9.2 Hz, H-2I), 3.61
(q, 1H, J 6.4 Hz, H-5II), 3.70–3.85 (m, 6H, one proton of
IV
I
IV
III
OCH2H-2II, H -2 , H -5, H -5 , H -2 ), 3.87 (dd, 1H, J
3.7, 9.4 Hz, H-2V), 3.91–4.00 (m, 4H, H-4II, H -4 ), H-
IV
5III, H -5 ), 4.16 (dd, 2H, J 2.8, 9.4 Hz, H-3I, H -3 ), 4.35
V
III
(d, 1H, J 7.6 Hz, H-1I), 4.40–4.70 (m, 13H, PhCH2), 4.78

2090
Y. Hua et al. / Carbohydrate Research 339 (2004) 2083–2090
5. Mulloy, B.; Ribeiro, A.-C.; Alves, A.-P.; Vieira, R. P.;
H2O at 0.8 mL/min with detection by an RI detector.
The desired fractions were combined and freeze dried to
~
Mourao, P. A. S. J. Biol. Chem. 1994, 269, 22113–22123.
6. Alves, A.-P.; Mulloy, B.; Diniz, J. A.; Mourao, P. A. S.
25
~
give 1 (60 mg, 60%) as an amorphous white solid; ½aŠ
D
J. Biol. Chem. 1997, 272, 6965–6971.
~
7. Pereira, M. S.; Mulloy, B.; Mourao, P. A. S. J. Biol. Chem.
1999, 274, 7656–7667.
8. (a) Sinniger, V.; Tapon-Bretaudiere, J.; Millieu, C.;
Muller, D.; Jozefonvicz, J.; Fischer, A. M. J. Chromatogr.
1992, 615, 215–223; (b) Pereira, M. S.; Vilela-Silva, A.-C.
)75 (c 0.5, H2O); 13C NMR (600 MHz, D2O): d 100.9,
98.4, 98.2, 94.4, 93.1, 79.1, 79.0, 75.6, 75.5, 73.3, 72.9,
72.0, 71.9, 71.8, 70.5, 70.1, 69.0, 67.4, 67.3, 67.1, 66.9,
66.8, 66.7, 62.0, 30.6, 29.8, 28.3, 28.0, 27.9, 24.4, 21.6,
15.1, 15.0, 14.8, 13.0. Anal. Calcd for C38H61Na7O42-
S7Æ2H2O: C, 28.32; H, 4.04; S, 13.91. Found: C, 28.24;
H, 4.10; S, 13.78.
~
E. S.; Valente, A.-P.; Mourao, P. A. S. Carbohydr. Res.
2002, 337, 2231–2238.
9. Glabe, C. G.; Grabel, L. R.; Vacquier, V. D.; Rosen, S. D.
J. Cell. Biol. 1982, 94, 123–128.
10. (a) McClure, M. O.; Moore, J. P.; Blanc, D. F.; Scotting,
P.; Cook, G. M.; Keynes, R. J.; Weber, J. N.; Davies, D.;
Weiss, R. A. AIDS Res. Hum. Retroviruses 1992, 8, 19–26;
(b) Yoshida, T.; Hatanaka, K.; Uryu, T.; Kaneko, Y.;
Suzuki, E.; Miyano, H.; Mimura, T.; Yoshida, O.;
Yamamoto, N. Macromolecules 1990, 23, 3717–3722.
11. (a) Hahnenberger, R.; Jakobson, A. M. Glycoconjugate J.
1991, 8, 350–353; (b) Khoo, K.-H.; Sarda, S.; Xu, X.;
Caulfield, J. P.; McNeil, M. R.; Homans, S. W.; Morris,
H. R.; Dell, A. J. Biol. Chem. 1995, 270, 17114–171232; (c)
Foxall, C.; Watson, S. R.; Dowbencko, D.; Lasky, L. A.;
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Acknowledgements
This work was supported by National Basic Research
Program of China (2003CB415001) and NNSF of China
(Project 20372081 and 30330690). The authors thank
Dr. Ye Zhang (Medical cell biology, Beijing University)
for performing partial bioassay.
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