Study of carbohydrate-carbohydrate interactions: Total synthesis of 6d-deoxy Lewisx pentaosyl glycosphingolipid

Article abstract of DOI:10.1016/j.tet.2010.07.025

This article describes total synthesis of 6d-deoxy Lewis^x pentaosyl glycosphingolipid, a useful tool for study of the Lewis ^x-Lewis^x interaction. A 6-deoxy galactose donor was condensed with a diol of glucosamine to provide regioselectively a β 1→4 linked disaccharide, which was further fucosylated to a protected deoxy Lewis^x trisaccharide. Glycosylation of a lactoside diol with the 6d-deoxy Lewis^x trisaccharide gave regio- and stereoselectively a pentasaccharide in excellent yield. After chemical modification, this pentasaccharide reacted with the 3-O-benzoylated azidosphingosine to form a glycosphingolipid, which, after azide reduction followed by condensation with stearic acid and deprotection, afforded the target compound.

Full text of DOI:10.1016/j.tet.2010.07.025

Tetrahedron 66 (2010) 7373e7383
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Study of carbohydrateecarbohydrate interactions: total synthesis of 6d-deoxy
Lewisx pentaosyl glycosphingolipid
,
,
,
,b,
*
Yanyan Zhang a b, Dengxiang Dong a b, Tao Zhou a b, Yongmin Zhang a
a Université Pierre et Marie Curie-Paris 6, Institut Parisien de Chimie Moléculaire, UMR 7201 CNRS, 4 place Jussieu, 75005 Paris, France
b Guiyang College of Traditional Chinese Medicine, 50 Shidong Road, 550002 Guiyang, China
a r t i c l e i n f o
a b s t r a c t
This article describes total synthesis of 6d-deoxy Lewisx pentaosyl glycosphingolipid, a useful tool for
Article history:
Received 25 May 2010
Received in revised form 13 July 2010
Accepted 13 July 2010
Available online 21 July 2010
study of the LewisxeLewisx interaction. A 6-deoxy galactose donor was condensed with a diol of glu-
cosamine to provide regioselectively a
b 1/4 linked disaccharide, which was further fucosylated to
a protected deoxy Lewisx trisaccharide. Glycosylation of a lactoside diol with the 6d-deoxy Lewisx tri-
saccharide gave regio- and stereoselectively a pentasaccharide in excellent yield. After chemical modi-
fication, this pentasaccharide reacted with the 3-O-benzoylated azidosphingosine to form
a glycosphingolipid, which, after azide reduction followed by condensation with stearic acid and de-
protection, afforded the target compound.
Keywords:
Synthesis
Glycosylation
Ó 2010 Elsevier Ltd. All rights reserved.
Carbohydrateecarbohydrate interaction
Lewisx
Glycosphingolipid
1. Introduction
(NMR) spectroscopy,9 mass spectrometry (MS),10 vesicle adhe-
sion,11 atomic force microscopy (AFM)12 and surface plasmon res-
Proteineprotein interactions constitute an important mecha-
nism for cell adhesion that controls cellular behaviour.1 Because
most of the cell surface proteins are highly glycosylated, carbohy-
drateeprotein interactions are also involved in cell adhesion and
recognition.2,3 Recent advances in glycobiology revealed the exis-
tence of biologically significant carbohydrateecarbohydrate in-
teractions, and this type of interaction could have a general,
fundamental character for cell biology.4 A typical example is the
report of Hakomori who proposed that carbohydrateecarbohy-
drate interaction is responsible for the initial step of cell adhesion.5
Embryogenesis, metastasis and other proliferation processes are,
according to Hakomori, mediated by carbohydrateecarbohydrate
interactions.5 One of the structures involved in this novel mecha-
onance (SPR) spectroscopy.13 Rat basophilic leukaemia cells
pre-incubated with purified Lex-containing glycosphingolipids
have been used as a model.14 Another model system termed ‘Gly-
cosylated Foldamer’ was demonstrated for study of carbohy-
drateecarbohydrate interaction in terms of individual carbohydrate
motifs.15 By using a vesicle micromanipulation approach with
chemically synthesized natural Lex pentasaccharide glyco-
sphingolipid, we have demonstrated that in contrast to glyco-
neolipids,11 which allow strong orientational freedom of the Lex
group, the natural lipid showed a restricted orientation of the Lex
group. The adhesion induced by LexeLex interaction was thereby
considerably enhanced, indicating that relative orientation of the
two Lex groups is a predominant factor in LexeLex recognition.16 In
another experiment we replaced the Lex trisaccharide determinant
in the headgroup by its isomer Lea trisaccharide, in which the ga-
lactose and fucose are permutated relative to Lex on one vesicle
surface. The adhesion energy observed for LexeLea pair was very
weak, confirming the homotypic characteristic of this type of car-
bohydrateecarbohydrate interactions.16
nism is the Lewisx (Lex) trisaccharide determinant (Gal
[Fuc 1/3]GlcNAc
1). Lex is the terminal trisaccharide moiety of
b1/4
a
b
numerous cell surface glycolipids and glycoproteins involved in
selectin-mediated cellecell adhesion and recognition processes.6
The interaction between Lex and Lex was found to be homotypic,
and mediated by the presence of divalent cations, such as Ca2þ 7,8
.
Recently, the LexeLex interaction has been extensively studied
To date, however, the molecular detail of this type of weak and
Caþ2-dependent carbohydrateecarbohydrate interactions has not
yet been sufficiently clarified, which necessitates new models to
probe the nature of this phenomenon in term of key role played by
the different hydroxyl groups on Lex trisaccharide involved in the
LexeLex interaction. Our objective has been to prepare a series of
using a variety of techniques including nuclear magnetic resonance
* Corresponding author. Tel.: þ33 1 44276153; fax: þ33 1 44275504; e-mail
address: yongmin.zhang@upmc.fr (Y. Zhang).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.07.025

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Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
Lex pentaosyl glycosphingolipids in which one of the eight hydroxyl
groups of Lex trisaccharide is replaced by a hydrogen atom (Fig. 1),
and to test the induced adhesion by interaction of these derivatives,
in order to gain an insight into the functions of the hydroxyl groups
in Lex trisaccharide molecule.
treated by phenyl chlorothionocarbonate to give compound 8 in 95%
yield. Radical reaction of 8, using tributyltin hydride and AIBN,
provided the deoxy derivative 9 in 61% yield. Compound 9 was
previously prepared from D
-fucose by a shorter route,19 but the
starting material is much more expensive.
OH
O
HO
OH
O
HO
O
OH
O
OH
6
4
C17H35
HN
5
b
O
1
c
O
d
O
HO
O
a
O
3
HO
O
OH
2
2
6
4
C12H25
OH
NHAc
3
1
OH
5
H3C
HO
O
OH
e
OH
OH
Lex Trisaccharide
Figure 1. Sites identified as interacting moieties for the Lex pentaosyl glycosphingolipid.
Taking the cost of different sugar residues of Lex trisaccharide
into account, the synthetic work was started from chemical mod-
ification of galactose residue. After successful synthesis of the 3d-
and 4d-deoxy Lex pentaosyl glycosphingolipids,17 here we report an
efficient synthesis of 6d-deoxy Lex pentaosyl glycosphingolipid 1
(Fig. 2), which would be a useful tool for a mechanistic study of
carbohydrateecarbohydrate interactions.
Hydrolysis of the anomeric phenylthio group by BF3$Et2O in the
presence of HgO (red) gave the hemiacetal 1020 as a mixture of
a/b isomers in 56% yield, which were not separated and further
characterized. Treatment of 10 with trichloroacetonitrile in the
presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) gave the
desired trichloroacetimidate 2a in 58% yield. 1H NMR spectrum
showed that only
a
-trichloroacetimidate was formed in the re-
OH
HO
HO
O
OH
O
CH3
OH
6
O
O
4
C17H35
HN
5
b
O
c
O
d
O
HO
O
1
a
O
3
HO
O
OH
2
2
6
4
C12H25
OH
NHAc
3
1
OH
5
H3C
HO
O
OH
e
OH
OH
Figure 2. 6d-Deoxy Lex pentaosyl glycosphingolipid 1.
2. Results and discussion
action on the basis of the H-1, H-2 coupling constant (J1,2¼3.5 Hz),
as shown in Scheme 1.
For synthesis of the target 1, compounds 2e6 were chosen as
building blocks (Fig. 3).
As illustrated in Scheme 2, the donor 2a and acceptor 3 are
designed to take advantage of the differences in the reactivity of
their leaving groups. Thus, condensation of the trichloroacetimidate
2a with the previously reported diol 3,21 using TMSOTf as promoter,
In order to synthesize the 6-deoxy galactosyl donor 2a, the pre-
viously reported phenyl 2,3,4-tri-O-acetyl-1-thio-
side 7,18 which was prepared from
-galactose by peracetylation,
glycosylation of thiophenol and 6-selective deacetylation, was
D-galactopyrano-
D
gave regioselectively the
b
1/4 linked disaccharide 11 in 79% yield,
1/3 linked disaccharide
due to the ‘stereo hindrance effect’, no
b
Figure 3. Key building blocks for synthesis of target 1.

Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
7375
Scheme 1. Reagents and conditions: (i) phenyl chlorothionocarbonate, CH2Cl2, pyridine, rt, 3 h, 95%; (ii) tributyltin hydride, AIBN, toluene, 80 ꢀC, 1 h, 61%; (iii) BF3$Et2O, HgO, H2O,
THF, rt, 1 h, 56%; (iv) Cl3CCN, DBU, CH2Cl2, 0 ꢀC, 1 h, 58%.
AcO
AcO
OBn
CH3
CH3
OBn
O
O
4
O
HO
HO
i
O
+
SPh
d
AcO
O
AcO
c
2
SPh
RO
1
NPhth
AcO
AcO
3
CCl3
O
NPhth
C
11 R = H
11' R = Ac
NH
2a
3
ii
Scheme 2. Reagents and conditions: (i) TMSOTf, CH2Cl2, 4 Å MS, 0 ꢀC, 1 h, 79%; (ii) Ac2O, pyridine, rt, 14 h, quant.
was isolated. Such a selective behaviour of phenyl 6-O-benzyl-2-
deoxy-2-phthalimido-1-thio- -glucopyranoside 3 has previously
been observed by our group22 during its glycosylation with 2,3,4,6-
tetra-O-benzoyl- -galactopyranosyl bromide.
The 1H NMR spectrum of 11 showed the presence of H-3c of the
glucosamine residue at
4.45 (dd, J2c,3c¼10.3 Hz, J3c,4c¼7.9 Hz),
With the disaccharide 11 in hand, we first used ethyl 2,3,4-tri-O-
b
-D
benzyl-1-thio-b-L
-fucopyranoside 4a26 for the fucosylation. The
reaction was performed using N-iodosuccinimide (NIS)/tri-
fluoromethanesulfonic acid (TfOH) as promoter at low temperature
to provide the desired trisaccharide 14, as shown in Scheme 4.
Surprisingly, the yields of the fucosylation were not satisfactory,
varying from 0e45%, despite of changing reaction conditions
(temperature, time, solvent, donor equivalence, etc.), we then
a-D
d
indicating the position of the newly formed glycosidic linkage in
the disaccharide 11 to be at OH-4 of the acceptor 3. This regiose-
lectivity was further confirmed from the 1H NMR spectrum of
110dobtained from 11 by acetylationdwhich revealed a deshielded
signal for H-3c at 5.72 ppm (dd, J2c,3c¼10.2 Hz, J3c,4c¼9.0 Hz), con-
firming therefore the position of the new glycosidic linkage in 11 as
being OH-4 of the diol 3. Its stereochemistry was determined to be
turned to other donors for fucosylation. The 2,3,4-tri-O-benzyl-L-
fucosyl fluoride 4b was therefore prepared from 4a by treatment
with DAST in the presence of NBS, based on the method of Nicolaou
et al.27,28 (Scheme 5). This reaction afforded high yield (98%) of 4b,
NMR revealed that 4b exist as a mixture of two isomers
Fucosyl fluoride 4b was also prepared by Ogawa et al.29 from methyl
2,3,4-tri-O-benzyl-1-thio-
-fucopyranoside and by Wong et al.30
from 2,3,4-tri-O-benzyl- -fucose both by reaction with DAST.
a and b (1:2).
the desired
b anomer on the basis of the H-1d, H-2d coupling
constant (J1d,2d¼7.9 Hz).
b-L
Another donor 2b has also been prepared for glycosylation, but
with a shorter way. As shown in Scheme 3, ethyl 2,3,4-tri-O-acetyl-
L
Glycosylation of disaccharide 11 with 4b was much effective
than 4a. Thus coupling of 4b and 11 in the presence of silver triflate
and stannous chloride provided the trisaccharide 14 in 76% yield
and with the newly generated glycosidic linkage of the desired
-configuration on the basis of the low value of the Fuc H-1, H-2
coupling constant (J1e,2e¼3.8 Hz). No formation of the corre-
1-thio-
-galactopyranoside 1223 was treated by phenyl chloro-
D
thionocarbonate to give compound 13 in 98% yield. Radical reaction
of 13, using tributyltin hydride and AIBN, provided the deoxy de-
rivative 2b in 82% yield. Glycosyl donor 2b was previously prepared
a
from expensive
D-fucose as a mixture of
a
/b
isomers.24
AcO
AcO
AcO
OH
OCSOPh
CH3
O
O
ii
i
O
SEt
SEt
AcO
AcO
SEt
AcO
OAc
OAc
OAc
12
2b
13
Scheme 3. Reagents and conditions: (i) phenyl chlorothionocarbonate, CH2Cl2, pyridine, rt, 3 h, 98%; (ii) tributyltin hydride, AIBN, toluene, 80 ꢀC, 1 h, 82%.
Interestingly, glycosylation of 3 with 2b gave regio- and ster-
eoselectively the desired disaccharide 11 in 61% yield, using NIS/
TfOH as promoter without affecting SPh group of the acceptor 3.
Such a selective reactivity between SEt and SPh groups has been
observed in our previous work.25
sponding b-fucosylated product was detected (Scheme 5). Contrary
to 4a, the glycosylation of 11 with 4b is easily reproducible.
Having the trisaccharide donor 14 at our disposal, we then
proceeded towards coupling the latter to the previously reported
diol 5.31 The reaction was promoted by NIS and triflic acid to afford

7376
Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
AcO
CH3
OBn
O
O
AcO
CH3
H3C
BnO
SEt
OBn
d
O
O
OBn
O
AcO
c
SPh
O
O
AcO
i
d
+
O
OBn
AcO
NPhth
c
SPh
HO
H3C
O
AcO
e
NPhth
OBn
OBn
11
4a
14
BnO
Scheme 4. Reagents and conditions: (i) NIS, TfOH, 4 Å MS, toluene, ꢁ30 ꢀC, 1 h, 45%.
H3C
SEt
OBn
H3C
BnO
F
OBn
O
O
ii
i
14
OBn
OBn
11
BnO
4a
4b
Scheme 5. Reagents and conditions: (i) DAST, NBS, ꢁ15 ꢀC, 30 min, 98%; (ii) AgOTf, SnCl2, CH2Cl2/toluene (5:1), ꢁ15 ꢀC, 1 h, 76%.
regio- and stereoselectively the desired pentasaccharide 15 in 82%
spectrum showed that only the a-trichloroacetimidate was
yield (Scheme 6). The stereochemistry of the newly introduced
formed on the basis of the H-1, H-2 coupling constant
(J1a,2a¼3.7 Hz) of the glucose residue.
linkage was determined to be
b on the basis of the GlcN H-1, H-2
coupling constant (J1c,2c¼8.4 Hz). The regioselectivity was con-
Condensation of trichloroacetimidate 19 with azidosphingosine
derivative 6 was performed using BF3$Et2O as promotor to provide
the desired glycolipid 20 in 57% yield, as shown in Scheme 9. The
1
firmed from the H NMR spectrum of 150dobtained from 15 by
acetylationdwhich revealed a deshielded signal for H-4b at
AcO
CH3
OBn
O
O
HO
O
OBn
AcO
OBn
SPh
O
AcO
O
O
NPhth
O
HO
+
OSE
BnO
H3C
BnO
O
BnO
OBn
BnO
OBn
5 OSE = OC2H4Si(CH3)3
14
i
AcO
RO
OBn
O
CH3
OBn
OBn
O
O
d
O
O
O
b
AcO
O
BnO
O
c
a
AcO
OSE
OBn
NPhth
OBn
H3C
BnO
O
e
OBn
OBn
15 R = H
15' R = Ac
ii
Scheme 6. Reagents and conditions: (i) NIS/TfOH, 4 Å MS, CH2Cl2, ꢁ15 ꢀC, 1 h, 82%; (ii) Ac2O, pyridine, rt, 14 h, 95%.
5.43 ppm (d, J3b,4b¼3.5 Hz), confirming therefore the position of the
b
configuration of the newly introduced glycosidic linkage was
new glycosidic linkage in 15 as being OH-3b of the diol 5.
confirmed from the 1H NMR spectrum (J1a,2a¼7.8 Hz). The azide
group of 20 was reduced by triphenyl phosphine in a mixture of
toluene and water at 45 ꢀC for 24 h to give an amino derivative. The
reaction temperature needs to be carefully controlled (below 50 ꢀC)
to avoid formation of byproduct. Due to its unstable property, the
amino derivative was not characterized at this stage and condensed
directly with stearic acid in the presence of 1-ethyl-3-(3-dime-
thylaminopropyl)carbodiimide (EDC) in dry dichloromethane to
give the glycosyl ceramide 21. 1H NMR spectrum of 21 showed
Treatment of pentasaccharide 15 with hydrazine in boiling
ethanol, followed by selective N-acetylation, afforded the com-
pound 16 in 86% overall yield from 15 (Scheme 7). Catalytic
hydrogenolysis of 16 and purification of the product on Sephadex
G25 provided quantitatively the pentasaccharide 17 (Scheme 7).
After peracetylation of 17, pentasaccharide 18 was obtained
(97% yield) and converted to a trichloroacetimidate donor in
order to couple with azidosphingosine derivative 6. Acid cata-
lyzed cleavage of the 2-(trimethylsilyl)ethyl glycoside was per-
formed in dichloromethane using trifluoroacetic acid to afford
a doublet at
d
5.73 ppm (J¼9.2 Hz) corresponding to the proton of
NH/CO group of the ceramide. The protecting groups of hydroxyl
groups were subsequently removed in basic condition (NaOMe) to
afford the target 6d-deoxy Lewisx pentaosyl glycosphingolipid 1 in
75% yield (Scheme 9).
the hemiacetals as a mixture of
a/b isomers, which were not
separated and further characterized at this stage. The hemi-
acetals were then treated with trichloroacetonitrile in the
presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) to give
the trichloroacetimidate 19 in 65% yield (Scheme 8). The 1H NMR
The compound 1 was fully characterized by 1H and 13C NMR, as
well as HRMS.

Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
7377
HO
HO
OBn
CH3
OBn
OBn
O
O
O
O
d
O
b
HO
O
BnO
O
c
a
O
HO
OSE
i
OBn
NHAc
OBn
15
H3C
BnO
HO
O
e
OBn
OBn
16
HO
OH
CH3
OH
OH
O
O
O
d
O
O
b
HO
O
HO
O
c
ii
a
O
HO
OSE
OH
NHAc
OH
H3C
O
e
OH
OH
HO
17
Scheme 7. Reagents and conditions: (i) (a) NH2NH2, H2O, EtOH, 80 ꢀC, 14 h; (b) Ac2O, MeOH, CH2Cl2, rt, 15 h, 86%. (ii) H2, Pd/C, MeOH, 30 ꢀC, 20 h, quant.
AcO
AcO
O
OAc
CH3
OAc
OAc
O
O
O
O
d
O
b
AcO
O
AcO
c
a
O
AcO
OSE
i
OAc
NHAc
OAc
17
H3C
AcO
O
e
OAc
OAc
18
AcO
AcO
OAc
CH3
OAc
OAc
O
O
O
ii
O
d
O
b
AcO
O
AcO
O
c
a
O
AcO
OAc
NHAc
AcO
CCl3
O
H3C
O
e
OAc
NH
OAc
AcO
Scheme 8. Reagents and conditions: (i) Ac2O, pyridine, DMAP, 30 ꢀC, 14 h, 97%; (ii) (a) TFA, CH2Cl2, 0 ꢀC for 1 h, then rt for 5 h; (b) Cl3CCN, DBU, CH2Cl2, 0 ꢀC, 4 h, 65% (two steps).
19
AcO
AcO
AcO
O
CH3
OAc
O
OAc
OAc
O
O
O
d
N3
O
b
c
O
4
a
3
O
O
C13H27
N3
AcO
AcO
i
OAc
2
NHAc
5
1
OAc
+
HO
C13H27
19
OBz
O
H3C
AcO
e
OAc
OBz
OAc
20
6
O
AcO
AcO
O
CH3
OAc
O
OAc
O
OAc
O
NH
C17H35
iii
d
O
O
b
AcO
c
O
4
a
1
3
O
O
C13H27
AcO
ii
AcO
OAc
2
5
NHAc
1
OAc
OBz
H3C
AcO
O
e
OAc
OAc
21
Scheme 9. Reagents and conditions: (i) BF3$Et2O, CH2Cl2, 4 Å powdered molecular sieves, ꢁ10 ꢀC, 3 h, 57%; (ii) (a) Ph3P, H2O, toluene, 45 ꢀC, 24 h; (b) stearic acid, EDC, CH2Cl2, rt,
24 h, 61%; (iii) NaOMe/MeOH, rt, 14 h, 75%.
3. Conclusion
been shown that a two-step deoxygenation of galactose at
position 6 could be easily realised by reaction with phenyl
chlorothionocarbonate, followed by a radical reaction using
Bu3SnH and catalyzed by AIBN, giving the 6-deoxy derivative in
In conclusion, we have developed a concise synthesis of 6d-
deoxy Lewisx pentaosyl glycosphingolipid in good yield. It has

7378
Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
high yield. Our successful disaccharide synthesis was based on
a highly regio- and stereoselective glycosylation, taking ad-
vantages of stereo hindrance effect of the acceptor and par-
HRMS (m/z) calcd for C25H30O9S2N (MþNHþ4 ): 552.1365. Found:
552.1362.
ticipating effect of the donor, to provide the
b
1/4 linked
4.3. Synthesis of O-(2,3,4-tri-O-acetyl-a-D-fucopyranosyl)
disaccharide in high yield. Some difficulties were encountered
however when preparing the trisaccharide 14 by fucosylation of
11 with the thioglycoside 4a, which used to be effective for
such a glycosylation, this problem was solved by using the
fluoride donor 4b, which was proved to be very powerful for
fucosylation of 11, giving the desired trisaccharide 14 in high
yield. Construction of the pentasaccharide 15 was successfully
achieved in very good yield by a highly regio- and stereo-
selective glycosylation of the diol 5 with the donor 14, taking
advantage of the activity difference between OH-3b and OH-4b.
With the key pentasaccharide 15 in hand, the classic glyco-
sphingolipid synthesis method was then applied to give
smoothly the target compound 1. After synthesis of the 3d- and
4d-deoxy Lex pentaosyl glycosphingolipids,17 this work allowed
us to obtain the third member of the deoxy family on galactosyl
residue of the Lex pentaosyl glycosphingolipid. Synthetic work
is in progress in our laboratory towards to the last member of
this family, the 2d-deoxy Lex pentaosyl glycosphingolipid.
These compounds will be used to perform a mechanistic study
of LexeLex interaction for the effect of hydroxyl groups of ga-
lactose on the induced adhesion using the vesicle microma-
nipulation technique.16
trichloroacetimidate (2a)
Compound 9 (320 mg, 0.84 mmol, 1 equiv) was dissolved in THF
(2.7 mL) and water (0.5 mL). A mixture of HgO (265 mg, 1.22 mmol,
1.5 equiv) and BF3$Et2O (0.33 mL, 2.6 mmol, 3 equiv) in THF
(2.7 mL) was added dropwise to the preceding solution. The mix-
ture was stirred for 1 h after addition, and then concentrated and
poured into ether. The mixture was successively washed with
a saturated NaHCO3 solution, a 10% potassium iodide aqueous so-
lution and water, dried over MgSO4 and then concentrated. The
crude product 10 obtained in a/b isomers were directly engaged in
the following step without further purification. To a solution of 10
(100 mg, 3.44 mmol, 1 equiv) in anhydrous dichloromethane
(3.5 mL) were added trichloroacetonitrile (0.39 mL, 3.91 mmol,
11.5 equiv) and DBU (52 m
L, 0.34 mmol, 1 equiv) dropwise at 0 ꢀC
and stirred for 1 h. After concentration, the residue was purified by
silica gel column chromatography (cyclohexane/ethyl acetate/tri-
ethylamine 300:100:0.4) to give compound 2a as a white foam
(86.5 mg, 58%). The NMR data were identical to those reported in
literature.32
4.4. Synthesis of phenyl (2,3,4-tri-O-acety-
fucopyranosyl)-(1/4)-6-O-benzyl-2-deoxy-2-phthalimido-1-
thio- -glucopyranoside (11)
b-D-
b-D
4. Experimental
4.1. General
4.4.1. Method A (2aþ3). A solution of 2a (95 m g, 0.22 mmol,
1 equiv) and 3 (107 mg, 0.22 mmol, 1 equiv) in 2.5 mL of anhydrous
dichloromethane was stirred with 4 Å powdered molecular sieves
for 40 min at room temperature under nitrogen. Trimethylsilyl
Optical rotations were measured at 589 nm (Na line) at 20ꢂ2 ꢀC
with a PerkineElmer Model 343 digital polarimeter, using a 10 cm,
1 mL cell. High resolution mass spectra (HRMS) were recorded with
a Bruker micrOTOF spectrometer in electrospray ionization (ESI)
mode. 1H NMR spectra were recorded with a Bruker DRX 400
spectrometer at ambient temperature. Assignments were aided by
COSY experiments. 13C NMR spectra were recorded at 100.6 MHz
with a Bruker DRX 400 for solutions in CDCl3, CD3OD or D2O. Re-
actions were monitored by thin-layer chromatography (TLC) on
a precoated plate of silica gel 60 F254 (Merck, 0.2 mm) and detection
by charring with sulfuric acid. Flash column chromatography was
performed on silica gel 60 (230e400 mesh, Merck).
triflate (40 m
L, 0.22 mmol, 1 equiv) was added at 0 ꢀC, and stirring
continued for 1 h. The mixture was filtered through Celite. The
filtrate was washed with a saturated aqueous NaHCO3 and then
with water, dried over MgSO4 and concentrated. The residue was
purified by silica gel column chromatography (cyclohexane/ethyl
acetate 1.5:1) to give 11 (0.13 g, 79%) as a white amorphous solid.
4.4.2. Method
B
(2bþ3). A mixture of 2b (0.4 g, 1.20 mmol,
1 equiv), 3 (0.59 g,1.20 mmol,1 equiv) and 4 Å powdered molecular
sieves (1 g) in dry toluene (12 mL) was stirred at room temperature
under nitrogen for 30 min, then cooled to ꢁ20 ꢀC. NIS (323 mg,
1.44 mmol, 1.2 equiv) and then TfOH (21.2 mL, 0.24 mmol, 0.2 equiv)
4.2. Synthesis of phenyl 2,3,4-tri-O-acetyl-6-
phenoxythiocarbonyl-1-thio-b-D-galactopyranoside (8)
were added. The mixture was stirred at ꢁ20 ꢀC for 2 h, then neu-
tralized with Et3N, diluted with dichloromethane, filtered through
Celite, washed with aqueous sodium thiosulfate, brine and then
dried over MgSO4 and concentrated. After purification by flash
column chromatography (cyclohexane/ethyl acetate 1.5:1), com-
To a solution of 7 (0.63 g, 1.58 mmol, 1 equiv) in anhydrous
dichloromethane (6 mL) and pyridine (6 mL) was added dropwise
phenyl chlorothionocarbonate (0.33 mL, 2.37 mmol, 1.5 equiv) at
room temperature. After stirring for 3 h, the mixture was con-
centrated and filtered by a short silica gel column using acetone as
solvent. The residue was then purified by silica gel column chro-
matography (cyclohexane/ethyl acetate 4:1) to give product 8
pound 11 was obtained (0.56 g, 61%) as a white amorphous solid:
20
Rf¼0.42 (cyclohexane/ethyl acetate 1:1); [
a
]
þ26.1 (c 1.0, chlo-
D
roform); 1H NMR (400 MHz, CDCl3):
d
7.89e7.20 (m, 14H, arom),
5.58 (d, 1H, J1,2¼10.5 Hz, H-1c), 5.17 (dd, 1H, J3,4¼3.5 Hz, J4,5<1 Hz,
H-4d), 5.12 (dd, 1H, J1,2¼7.9 Hz, J2,3¼10.3 Hz, H-2d), 4.92 (dd, 1H,
J2,3¼10.3 Hz, J3,4¼3.5 Hz, H-3d), 4.70, 4.51 (2d, 2H, Jgem¼11.8 Hz,
PhCH2), 4.45 (dd, 1H, J2,3¼10.3 Hz, J3,4¼7.9 Hz, H-3c), 4.42 (d, 1H,
J1,2¼7.9 Hz, H-1d), 4.25 (t, 1H, J1,2¼10.5 Hz, J2,3¼10.3 Hz, H-2c), 4.11
(s, 1H, exch. D2O, OH-3c), 3.78e3.66 (m, 5H, H-4c, H-5c, H-5d, H-6c,
H-60c), 2.11, 2.00, 1.96 (s, 9H, 3ꢃOAc), 1.14 (d, 3H, J5,6¼6.6 Hz, H-6d).
(0.79 g, 95%) as a white amorphous solid: Rf¼0.44 (cyclohexane/
20
ethyl acetate 2:1); [
(250 MHz, CDCl3):
a
]
þ17.7 (c 1.2, chloroform); 1H NMR
D
d 7.61e7.43 (m, 4H, arom), 7.37e7.11 (m, 6H,
arom), 5.51 (dd, 1H, J3,4¼3.2 Hz, J4,5<1 Hz, H-4), 5.29 (t, 1H,
J2,3¼9.9 Hz, H-2), 5.10 (dd, 1H, J2,3¼9.9 Hz, J3,4¼3.3 Hz, H-3), 4.81
(d, 1H, J1,2¼10.0 Hz, H-1), 4.65 (2dd, 2H, J6b,6a¼11.4 Hz, H-6a, H-
6b), 4.20 (m, 1H, H-5), 2.18, 2.14, 2.03 (3s, 9H, 3ꢃOAc). 13C NMR
13C NMR (100.6 MHz, CDCl3):
d 170.55, 170.12, 169.25 (3C]O, Ac),
168.23, 167.67 (2C]O, NPhth), 138.20, 132.16, 131.93, 131.85 (arom
C), 134.18, 132.78, 128.94, 128.61, 128.00, 127.96, 127.94, 123.86,
123.36 (arom CH), 101.16 (C-1d), 83.54 (C-1c), 81.00 (C-4c), 78.37
(C-5d), 73.72 (PhCH2), 71.13 (C-3d), 70.81 (C-3c), 69.91 (C-4d), 69.79
(C-2d), 68.93 (C-5c), 68.18 (C-6c), 55.30 (C-2c), 21.14, 20.84, 20.65
(62.5 MHz, CDCl3):
d 194.65 (C]S), 170.12, 169.92, 169.36 (C]O),
153.3 (OePh), 132.45, 132.37 (arom C), 129.55, 128.91, 128.14,
126.67, 121.73 (arom CH), 86.66 (C-1), 74.02, 71.83, 67.35, 67.12(C-
2, C-3, C-4, C-5), 70.62 (C-6), 20.78, 20.65, 20.52 (3CH3, Ac). ESI-

Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
7379
(3CH3, Ac), 15.93 (CH3). ESI-HRMS (m/z) calcd for C39H41NO13SNa
4.8. Synthesis of 2,3,4-tri-O-benzyl- -fucosyl fluoride (4b)
L
(MþNaþ): 786.2191. Found: 786.2195.
Ethyl 2,3,4-tri-O-benzyl-1-thio-b-L-fucopyranoside 4a (70 mg,
0.15 mmol, 1 equiv) was dissolved in anhydrous dichloromethane
(2 mL) under nitrogen and cooled to ꢁ15 ꢀC. The stirred solution
was then treated with (diethylamino)sulfur trifluoride and allowed
to stir for 3 min before N-bromosuccinimide was added. The mix-
ture was stirred for 30 min, then diluted with dichloromethane and
poured into an ice-saturated NaHCO3 solution, the organic phase
was separated and washed with saturated NaHCO3 solution and
brine before drying and evaporation. The residue so obtained was
purified by silica gel column chromatography (cyclohexane/ethyl
4.5. Synthesis of phenyl (2,3,4-tri-O-acety-b-D-
fucopyranosyl)-(1/4)-3-O-acetyl-6-O- benzyl-2-deoxy-2-
phthalimido-1-thio-
b-D
-glucopyranoside (110)
A solution of 11 (30 mg) in 1 mL of pyridine and 0.5 mL of acetic
anhydride was stirred at room temperature for 14 h and then
concentrated, co-evaporated with toluene and dried. Compound
110 was obtained in quantitative yield (32 mg), Rf¼0.48 (cyclohex-
20
ane/ethyl acetate 1:1); [
(400 MHz, CDCl3):
a
]
D
þ20 (c 1.0, chloroform); 1H NMR
acetate 13:1) to give 4b as colourless oil (63 mg, 98%,
a
/
b
¼1:2).
d 7.85e7.20 (m, 14H, arom), 5.72 (dd, 1H,
Their NMR spectral data were in good agreement with those
J3,4¼9.0 Hz, J2,3¼10.2 Hz, H-3c), 5.70 (d, 1H, J1,2¼10.6 Hz, H-1c), 5.11
(d, 1H, J4,5¼3.4 Hz, H-4d), 5.00 (dd, 1H, J1,2¼8.0 Hz, J2,3¼10.4 Hz, H-
2d), 4.85 (dd, 1H, J2,3¼10.4 Hz, J3,4¼3.5 Hz, H-3d), 4.74 (d, 1H,
Jgem¼12.0 Hz, one of the PhCH2), 4.53 (d, 1H, Jgem¼11.9 Hz, one of
the PhCH2), 4.47 (d, 1H, J1,2¼8.0 Hz, H-1d), 4.28 (t, 1H,
J1,2¼J2,3¼10.4 Hz, H-2c), 4.00 (t, 1H, J3,4¼9.3 Hz, J4,5¼9.6 Hz, H-4c),
3.80 (d, 2H, J5,6¼2.3 Hz, H-6c, H-60c), 3.69 (dt, 1H, J4,5¼10.0 Hz,
J5,6¼2.3 Hz, H-5c), 3.54 (dd, 1H, J5,6¼6.3 Hz, H-5d), 2.11, 1.96, 1.95,
1.86 (4s, 12H, 4ꢃOAc), 1.11 (d, 3H, J5,6¼6.4 Hz, H-6d). 13C NMR
reported in literature.28
4.9. Synthesis of phenyl (2,3,4-tri-O-acety-
fucopyranosyl)-(1/4)-[2,3,4-tri-O-benzyl-
b
-D-
a
-
L-fucopyranosyl-
(1/3)]-6-O-benzyl-2-deoxy-2-phthalimido-1-thio-b-D-
glucopyranoside (14)
A solution of 11 (0.30 g, 0.39 mmol, 1 equiv) and 4b (0.29 g,
0.66 mmol, 1.7 equiv) in 10 mL of dry dichloromethane and 2 mL
of dry toluene was stirred with 4 Å powdered molecular sieves for
30 min at room temperature under nitrogen. A mixture of stan-
nous chloride and silver triflate was added at ꢁ15 ꢀC, and the
stirring was continued for 1 h. The mixture was filtered through
Celite and washed with dichloromethane. The filtrate was washed
with a saturated NaHCO3 solution, then with water, dried over
MgSO4 and concentrated. After purification by flash column
chromatography (cyclohexane/ethyl acetate 4:1), compound 14
was obtained (0.35 g, 76%) as a white amorphous solid: Rf¼0.45
(100.6 MHz, CDCl3):
d 170.78, 170.31, 170.05, 169.15 (4C]O, Ac),
167.87, 167.43 (2C]O, NPhth), 138.15, 131.89, 131.55, 131.44 (arom
C), 134.49, 134.24, 133.26, 129.01, 128.65, 128.31, 128.04, 128.00,
123.88, 123.64 (arom CH), 100.57 (C-1d), 83.15(C-1c), 79.16 (C-5c),
75.48 (C-4c), 73.78 (PhCH2), 72.40 (C-3c), 71.58 (C-3d), 70.24 (C-
4d), 69.42 (C-2d), 69.13 (C-5d), 67.87 (C-6c), 54.08 (C-2c), 20.90,
20.81, 20.79, 20.72 (4CH3, Ac), 16.17 (C-6d). ESI-HRMS (m/z) calcd
for C41H43NO14SNa (MþNaþ): 828.2296. Found: 828.2334.
20 þ4.7 (c 1.0, chloroform); 1H
4.6. Synthesis of ethyl 2,3,4-tri-O-acetyl-6-
phenoxythiocarbonyl-1-thio-b-D-galactopyranoside (13)
(cyclohexane/ethyl acetate 2:1); [
NMR (400 MHz, CDCl3):
a
]
D
d
7.73e7.11 (m, 29H, arom), 5.53 (d, 1H,
J1,2¼10.5 Hz, H-1c), 5.10e5.09 (m, 1H, H-4d), 5.04 (dd, 1H,
J1,2¼8.5 Hz, J2,3¼9.8 Hz, H-2d), 4.88 (d, 1H, J1,2¼3.8 Hz, H-1e), 4.86
(d, 1H, Jgem¼11.9 Hz, one of the PhCH2), 4.85e4.77 (m, 5H, H-3c, H-
3d, H-5e, PhCH2), 4.72 (d, 1H, J1,2¼8.5 Hz, H-1d), 4.59 (d, 1H,
J1,2¼10.5 Hz, H-2c), 4.68, 4.57 (2d, 2H, Jgem¼11.6 Hz, PhCH2), 4.55,
4.48 (2d, 2H, Jgem¼12.2 Hz, PhCH2), 4.30e4.21 (m, 2H, one of the
PhCH2, H-4c), 4.03e3.85 (m, 4H, H-2e, H-3e, H-6c, H-6c0),
3.65e3.64 (m, 1H, H-4e), 3.61 (d, 1H, J¼9.7 Hz, H-5c), 3.43e3.38
(m, 1H, H-5d), 2.06, 1.99, 1.90 (3s, 9H, 3ꢃOAc), 1.26 (d, 3H,
J5,6¼6.5 Hz, H-6e), 1.08 (d, 3H, J5,6¼6.3 Hz, H-6d). 13C NMR
To a solution of 12 (0.22 g, 0.63 mmol, 1 equiv) in anhydrous
dichloromethane (2 mL) and pyridine (2 mL) was added dropwise
phenyl chlorothionocarbonate (0.13 mL, 0.94 mmol, 1.5 equiv) at
room temperature. After stirring for 3 h, the mixture was concen-
trated and then filtered by a short silica gel column using acetone as
solvent. The residue was then purified by silica gel column chro-
matography (cyclohexane/ethyl acetate 3.5:1) to give product 13
(0.30 g, 98%) as a white amorphous solid: Rf¼0.42 (cyclohexane/
ethyl acetate 2:1); [
a
]
20 þ45 (c 1.0, chloroform); 1H NMR (200 MHz,
D
CDCl3):
d
7.48e7.30 (m, 3H, arom), 7.14e7.10 (m, 2H, arom),
(100.6 MHz, CDCl3):
d 170.26, 170.18, 168.95 (3C]O, Ac), 139.05,
5.56e5.55 (m, 1H, H-4), 5.31 (t, 1H, J2,3¼9.9 Hz, H-2), 5.13 (dd, 1H,
J2,3¼9.9 Hz, J3,4¼3.2 Hz, H-3), 4.65e4.56 (m, 3H, H-1, H-6a, H-6b),
4.21e4.15 (m, 1H, H-5), 2.82e2.76 (m, 2H, SCH2), 2.21, 2.11, 2.03 (3s,
9H, 3ꢃOAc), 1.34 (t, 3H, J¼7.5 Hz, CH3). 13C NMR (100.6 MHz,
138.85, 138.23, 138.11, 132.53, 131.84, 129.16 (arom C), 134.35,
132.61, 128.94, 128.64, 128.35, 128.23, 128.12, 128.10, 128.01,
127.90, 127.56, 127.40, 127.36, 127.04, 123.83 (arom CH), 99.53 (C-
1d), 97.42 (C-1e), 84.43 (C-1c), 79.84 (C-3e), 79.74 (C-5c), 77.94 (C-
4e), 75.21 (C-2e), 74.81 (C-4c), 73.37 (C-3c), 74.26, 73.58, 73.12,
72.93 (4ꢃPhCH2), 71.52 (C-3d), 70.53 (C-4d), 69.16 (C-2d), 68.99
(C-5d), 68.01 (C-6c), 66.59 (C-5e), 55.74 (C-2c), 20.87, 20.69, 20.65
(3ꢃCH3CO), 16.78 (C-6e), 16.24 (C-6d). ESI-HRMS (m/z) Calcd for
C66H69NO17SNa (MþNaþ): 1202.4178. Found: 1202.4165.
CDCl3):
d 194.47 (C]S), 170.04, 169.80, 169.39 (C]O), 153.25
(OePh), 129.47, 126.56, 121.66 (arom CH), 83.92 (C-1), 73.92, 71.67,
67.47, 67.08 (C-2, C-3, C-4, C-5), 70.66 (C-6), 24.23 (CH2eCH3),
20.67, 20.60, 20.45 (3CH3CO), 14.78 (CH2eCH3). ESI-HRMS (m/z)
calcd for C21H26O9S2N (MþNaþ): 509.0946. Found: 509.0916.
4.7. Synthesis of ethyl 2,3,4-tri-O-acetyl-1-thio-
fucopyranoside (2b)
b
-
D
-
4.10. Synthesis of 2-(trimethylsilyl)ethyl (2,3,4-tri-O-acety-
-fucopyranosyl)-(1/4)-[2,3,4-tri-O-benzyl-
fucopyranosyl-(1/3)]-6-O-benzyl-2-deoxy-2-phthalimido-
-glucopyranoside-(1/3)-(2,6-di-O-benzyl-
galactopyranosyl)-(1/4)-2,3,6-tri-O-benzyl-b-D-
glucopyranoside (15)
b-
D
a-L-
b-
Compound 13 (1.64 g, 3.37 mmol, 1 equiv) was dissolved in an-
hydrous toluene (65 mL). The tributyltin hydride (1.82 mL,
6.75 mmol, 2 equiv) and AIBN (33.2 mg, 0.20 mmol, 0.06 equiv)
were added. The mixture was refluxed at 80 ꢀC for 1 h, then con-
centrated and purified by silica gel column chromatography (tolu-
ene/ethyl acetate 8:1) to give the compound 2b (0.92 g, 82%) as
a white foam, Rf¼0.44 (toluene/ethyl acetate 4:1). The NMR data
were proved to be identical to those reported in literature.24
D
b-D-
A solution of 14 (350 mg, 0.297 mmol, 1 equiv) and 5 (318 mg,
0.356 mmol,1.2 equiv) in 21 mL of dry dichloromethane was stirred
with 4 Å powdered molecular sieves (700 mg) for 30 min at room
temperature under nitrogen, then cooled to ꢁ15 ꢀC. NIS (146.3 mg,

7380
Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
0.65 mmol, 2.2 equiv), then TfOH (8.61
m
L, 0.097 mmol, 0.33 equiv)
16.21 (C-6d), ꢁ1.32 (SiMe3). ESI-HRMS (m/z) calcd for
C114H129NO29SiNa (MþNaþ): 2026.8312. Found: 2026.8250.
were added. The mixture was stirred at ꢁ15 ꢀC for 1 h, then neu-
tralized with Et3N, filtered through Celite and concentrated. The
residue was washed with aqueous sodium thiosulfate, water, and
brine and then dried over MgSO4 and concentrated. After purifi-
cation by flash column chromatography (cyclohexane/ethyl acetate
4.12. Synthesis of 2-(trimethylsilyl)ethyl (
(1/4)-[2,3,4-tri-O-benzyl- -fucopyranosyl-(1/3)]-6-O-
benzyl-2-deoxy-2-acetamido- -glucopyranoside-(1/3)-
(2,6-di-O-benzyl- -galactopyranosyl)-(1/4)-2,3,6-tri-O-
benzyl- -glucopyranoside (16)
b-D-fucopyranosyl)-
a-L
b-D
2.5:1), compound 15 was obtained (477 mg, 82%) as a white foam:
b-D
20
Rf¼0.46 (toluene/ethyl acetate 3:1); [
a
]
þ5.0 (c 1.0, chloroform);
D
b-D
1H NMR (400 MHz, CDCl3):
d
7.42e7.02 (m, 49H, arom), 5.31 (d, 1H,
J1,2¼8.4 Hz, H-1c), 5.12e5.11 (m, 1H), 5.07e4.85 (m, 4H), 4.83 (d, 1H,
J1,2¼3.6 Hz, H-1e), 4.82e4.64 (m, 10H, H-1d), 4.58 (d, 1H,
Jgem¼11.9 Hz, one of the PhCH2), 4.56 (d, 1H, J1,2¼8.4 Hz, H-2c),
4.53e4.46 (m, 5H), 4.40e4.31 (m, 3H, H-1a), 4.29e4.17 (m, 4H, H-
1b), 4.11 (br s, 1H), 3.98e3.96 (m, 2H, 1H of OCH2), 3.94e3.81 (m,
3H, H-6), 3.77e3.73 (m, 2H, 2ꢃH-6), 3.64e3.62 (m, 2H), 3.58e3.51
(m, 3H, 1H of OCH2, H-6), 3.49e3.33 (m, 6H, H-5d, PhCH2, H-6),
3.04e3.02 (m, 1H, one of the PhCH2), 2.82 (s, 1H, OH), 2.01, 1.96, 1.87
(3s, 9H, OAc), 1.21 (d, 3H, J5,6¼6.5 Hz, H-6e), 1.05 (d, 3H, J5,6¼6.4 Hz,
H-6d), 1.01e0.96 (m, 2H, OCH2CH2Si), 0.002 (s, 9H, SiMe3). 13C NMR
To a solution of compound 15 (82 mg, 0.042 mmol) in 11 mL of
ethanol, were added 0.7 mL of hydrazine monohydrate and 0.7 mL
of water. The mixture was refluxed at 80 ꢀC for 14 h. After con-
centration, the residue was co-evaporated with toluene and dried
over P2O5, then dissolved in 4 mL of methanol/dichloromethane
(1:1), to which 0.4 mL of acetic anhydride was introduced. The
mixture was stirred at room temperature overnight. After con-
centration, the residue was purified by a column of silica gel
(dichloromethane/methanol 50:1), and then by a Sephadex column
(LH-20) using methanol/dichloromethane (1:1) as eluant. Com-
(100.6 MHz, CDCl3):
d 170.23, 170.16, 168.89 (3C]O, Ac), 139.10,
pound 16 was obtained (62 mg, 86%, two steps) as a white amor-
138.91, 138.82, 138.71, 138.58, 138.54, 138.38, 138.10, 137.71 (arom
C), 133.97e123.38 (49arom CH), 103.07 (C-1b), 102.06 (C-1a), 99.46
(C-1d), 99.00 (C-1c), 97.25 (C-1e), 83.46, 82.90, 81.91, 79.55, 78.06,
77.65, 76.03, 75.24, 75.15, 74.92, 74.69, 72.56, 72.08, 71.40, 70.34,
69.04, 68.94, 67.51 (ring CH), 75.46, 74.96, 74.11, 73.68, 73.39, 72.98,
72.90, 72.83 (PhCH2), 68.42, 68.00, 67.87 (C-6a, C-6b, C-6c), 67.29
(OCH2CH2Si), 66.47 (C-5e), 56.33 (C-2c), 20.82, 20.66, 20.60 (CH3,
Ac), 18.47 (OCH2CH2Si), 16.74 (C-6e), 16.15 (C-6d), ꢁ1.36 (SiMe3).
ESI-HRMS (m/z) calcd for C112H127NO28SiNa (MþNaþ): 1984.8206.
Found: 1984.8190.
20
phous solid: Rf¼0.39 (dichloromethane/methanol 10:1); [
a
]
D
ꢁ15
(c 1.0, chloroform); 1H NMR (400 MHz, CDCl3):
d
7.43e7.15 (m, 45H,
arom), 5.81 (d, 1H, J¼7.0 Hz, NH), 5.19 (d, 1H, J1,2¼7.3 Hz, H-1c),
5.02e4.98 (m, 2H, H-1e, one of the PhCH2), 4.95e4.88 (m, 3H,
PhCH2), 4.74e4.53 (m,10H), 4.50e4.27 (m, 9H, H-1a, H-1b, H-1d, H-
5d), 4.24 (t,1H, J¼8.3 Hz, H-3c), 4.07e3.80 (m, 7H, H-2e, H-3e, H-4c,
OCHCH2Si), 3.71e3.67 (m, 2H, 2ꢃH-6), 3.62e3.29 (m, 20H, H-2a, H-
2b, H-2c, H-2d, H-4e, H-5e, OCHCH2Si, 2ꢃH-6), 1.39 (s, 3H, OAc),
1.25 (d, 3H, J5,6¼6.4 Hz, H-6e), 1.11 (d, 3H, J5,6¼6.4 Hz, H-6d),
1.05e1.00 (m, 2H, OCH2CH2Si), 0.03 (s, 9H, SiMe3). 13C NMR
(100.6 MHz, CDCl3):
d 170.85 (C]O, Ac), 139.27, 139.07, 138.94,
4.11. Synthesis of 2-(trimethylsilyl)ethyl (2,3,4-tri-O-acety-
-fucopyranosyl)-(1/4)-[2,3,4-tri-O-benzyl-
fucopyranosyl-(1/3)]-6-O-benzyl-2-deoxy-2-phthalimido-
-glucopyranoside-(1/3)-(4-O-acetyl-2,6-di-O-benzyl-
b-
138.72, 138.67, 138.63, 138.54, 138.41, 138.01 (arom C),
128.67e127.29 (arom CH), 103.20 (C-1b), 102.33 (C-1a), 100.73 (C-
1d), 99.96 (C-1c), 98.04 (C-1e), 83.05, 82.29, 82.08, 79.53, 79.10,
77.75, 76.61, 76.48, 76.01, 75.19, 74.59, 74.42, 73.92, 73.10, 71.71,
70.96, 70.58, 67.75, 67.19 (ring CH), 75.47, 75.07, 75.03, 74.73, 74.04,
73.47, 73.21, 72.56 (PhCH2), 69.44, 68.91, 68.46, 67.39 (3C-6,
OCH2CH2), 57.23 (C-2c), 23.03 (CH3, Ac), 18.58 (OCH2CH2Si), 16.85
(C-6e), 16.49 (C-6d), ꢁ1.29 (SiMe3). ESI-HRMS (m/z) calcd for
C100H121NO24SiNa (MþNaþ): 1770.7940. Found: 1770.7933.
D
a-L-
b-
D
b-D-
galactopyranosyl)-(1/4)-2,3,6-tri-O-benzyl-b-D-
glucopyranoside (150)
A solution of 15 (46 mg) and 20 mg of DMAP in 1 mL of pyridine
and 0.5 mL of acetic anhydride was stirred at room temperature for
14 h and then concentrated, co-evaporated with toluene and dried.
Compound 150 was obtained (45 mg, 95%); Rf¼0.48 (toluene/ethyl
20
acetate 3:1); [
CDCl3):
a]
þ3.0 (c 1.0, chloroform); 1H NMR (400 MHz,
4.13. Synthesis of 2-(trimethylsilyl)ethyl (
b-D-fucopyranosyl)-
D
d
7.42e6.82 (m, 49H, arom), 5.43 (d, 1H, J¼3.5 Hz, H-4b),
(1/4)-[ -fucopyranosyl-(1/3)]-2-deoxy-2-acetamido-b-D-
a
-L
5.21 (d, 1H, J1,2¼8.2 Hz, H-1c), 5.06e5.05 (m, 1H), 5.00e4.97 (m, 1H,
H-2e), 4.90 (d, 1H, Jgem¼12.2 Hz, one of the PhCH2), 4.87 (d, 1H,
Jgem¼11.7 Hz, one of the PhCH2), 4,81e4.76 (m, 2H), 4.74e4.71 (m,
4H, H-1d, H-1e, H-3c, H-5e), 4.67e4.63 (m, 2H, PhCH2), 4.61e4.50
(m, 4H), 4.42 (d, 1H, Jgem¼12.2 Hz, one of the PhCH2), 4.41 (d, 1H,
J1,2¼8.2 Hz, H-2c), 4.40e4.34 (m, 3H, H-2b, H-3e, one of the PhCH2),
4.26 (d,1H, J¼7.6 Hz, H-1a), 4.24e4.21 (m, 3H), 4.19 (d,1H, J¼8.0 Hz,
H-1b), 4.15e4.11 (m, 2H, H-4e, one of the PhCH2), 3.95 (d, 1H,
Jgem¼12.0 Hz, one of the PhCH2), 3.92e3.73 (m, 7H, H-2a, H-4c, H-
5c, 2ꢃH-6, OCH2CH2Si), 3.46e3.41 (m, 3H, H-5d, PhCH2), 3.37e3.25
(m, 6H, H-6), 3.02e2.99 (m, 1H, one of the PhCH2), 2.11, 2.06, 1.98,
1.88 (4s, 12H, 4ꢃOAc), 1.24 (d, 3H, J¼6.5 Hz, H-6e), 1.06 (d, 3H,
J¼6.3 Hz, H-6d), 0.98e0.93 (m, 2H, OCH2CH2Si), 0.02 (s, 9H, SiMe3).
glucopyranoside-(1/3)-(b-D-galactopyranosyl)-(1/4)-b-D-
glucopyranoside (17)
A solution of 16 (114 mg) in methanol (11 mL) was treated with
Pd/C (10%, 35 mg) under H2 (160 kPa) for 20 h at 30 ꢀC, then filtered
and evaporated. The residue was purified on a Sephadex column
(G25) using water as eluant. Compound 17 was obtained in quan-
titative yield (61 mg) as a white amorphous solid: Rf¼0.51 (iso-
propanol/ethyl acetate/water 3:3:2); [
1H NMR (400 MHz, D2O):
a
]
20 ꢁ49.6 (c 1.0, methanol);
D
d
5.16 (d, 1H, J1,2¼4.0 Hz, H-1e), 4.92e4.87
(m, 1H, H-5d), 4.74 (d, 1H, J1,2¼8.2 Hz, H-1), 4.53 (d, 1H, J1,2¼8.0 Hz,
H-1), 4.47 (d, 1H, J1,2¼7.8 Hz, H-1), 4.46 (d, 1H, J1,2¼7.8 Hz, H-1), 4.19
(d, 1H, J¼3.2 Hz), 4.10e3.59 (m, 25H), 3.49(dd, 1H, J1,2¼7.8 Hz,
J2,3¼9.8 Hz, H-2), 3.34e3.30 (m, 1H, H-2), 2.06 (s, 3H, Ac), 1.26 (d,
3H, J5,6¼6.4 Hz, H-6e), 1.21 (d, 3H, J5,6¼6.6 Hz, H-6d), 1.06 (2dt, 2H,
Jgem¼12.9 Hz, Jvic¼5.6 Hz, CH2Si), 0.06 (s, 9H, SiMe3). 13C NMR
13C NMR (100.6 MHz, CDCl3):
d 170.32, 170.23, 170.10, 169.05 (4C]
O, Ac), 139.28, 139.14, 138.93, 138.91, 138.62, 138.45, 138.39, 138.29,
131.42 (arom C), 128.57e123.43 (49 arom CH),103.23 (C-1b), 102.20
(C-2a), 99.48 (C-1d), 99.22 (C-1c), 97.10 (C-1e), 82.76 (C-5d), 75.88
(C-4c), 71.57 (C-4b), 70.11 (C-2e), 66.45 (C-5e), 56.84 (C-2c), 81.88,
79.64, 78.90, 78.84, 77.99, 75.68, 75.22, 74.80, 72.71, 71.80, 71.57,
70.57, 69.16, 68.95, 66.45 (CH), 75.25, 75.02, 74.21, 74.26, 73.60,
73.12, 72.98, 72.80 (PhCH2), 68.39, 67.82, 67.35 (3C-6, OCH2), 20.94,
20.86, 20.68, 20.64 (4CH3, Ac), 18.54 (OCH2CH2Si), 16.76 (C-6e),
(100.6 MHz, D2O):
d 174.67 (C]O, NHAc), 102.84, 102.50, 101.76,
101.28 (C-1a, C-1b, C-1c, C-1d), 98.43 (C-1e), 82.09, 78.32, 75.16,
74.86, 74.75, 74.53, 73.34, 72.61, 71.95, 71.00, 70.33, 69.96, 69.13,
68.29, 67.82, 66.68 (ring, CH), 72.82 (C-2), 70.80 (C-2), 68.43
(OCH2CH2Si), 60.94, 60.06, 59.63 (C-6a, C-6b, C-6c), 55.98 (C-2c),
22.25 (CH3, Ac), 17.56 (CH2Si), 15.80 (C-6e), 15.29 (C-6d), ꢁ2.55

Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
7381
(SiMe3). ESI-HRMS (m/z) calcd for C37H67NO24SiNa (MþNaþ):
4ꢃH-6), 3.82e3.72 (m, 5H, H-2e, H-4a, H-5c, H-5e), 3.68 (dd, 1H,
J2,3¼9.9 Hz, J3,4¼3.6 Hz, H-3d), 3.40e3.37 (m, 1H, H-5a), 3.12e3.07
(m,1H, H-2c), 2.17e1.92 (m, 42H, 14ꢃCH3CO),1.39 (d, 3H, J5,6¼6.4 Hz,
H-6e), 1.19 (d, 3H, J5,6¼6.5 Hz, H-6d). 13C NMR (100.6 MHz, CDCl3):
960.3714. Found: 960.3725.
4.14. Synthesis of 2-(trimethylsilyl)ethyl (2,3,4-tri-O-acetyl-
-fucopyranosyl)-(1/4)-[2,3,4-tri-O-acetyl-
fucopyranosyl-(1/3)]-(6-O-acetyl-2-deoxy-2-acetamido-
glucopyranosid)-(1/3)-(2,4,6-tri-O-acetyl-
b-
D
a
-
L
-
d 171.47, 171.18, 170.95, 170.83, 170.78, 170.53, 170.50, 170.32, 170.22,
b
-
D
-
169.80, 169.72, 169.58, 169.50, 168.97 (14ꢃCH3CO), 161.09 (C]NH),
100.93 (C-1d), 100.33 (C-1b), 99.22 (C-1c), 95.52 (C-1e), 92.97 (C-1a),
76.00, 75.24, 74.36, 73.19, 72.40, 71.56, 71.25, 71.20, 71.11, 71.07, 70.25,
70.05, 69.98, 69.44, 69.26, 69.17, 69.00, 67.98, 64.09 (19ꢃringC), 61.67,
61.55, 59.63 (3ꢃC-6), 58.76 (C-2c), 21.19e20.61 (14ꢃCH3CO),16.01 (C-
6e), 15.82 (C-6d). ESI-HRMS (m/z) calcd for C60H81Cl3N2O37Na
(MþNaþ): 1549.3476. Found: 1549.3446.
b-D-
galactopyranosyl)-(1/4)-2,3,6-tri-O-acetyl-b-D-
glucopyranoside (18)
A solution of 17 (52 mg) and DMAP (20 mg) in 4 mL of pyridine
and 2 mL of acetic anhydride was stirred at 30 ꢀC for 14 h and then
concentrated, co-evaporated with toluene. The residue was purified
by flash column chromatography (dichloromethane/methanol
4.16. Synthesis of (2,3,4-tri-O-acetyl-
(1/4)-[2,3,4-tri-O-acetyl- -fucopyranosyl-(1/3)]-(6-O-
acetyl-2-deoxy-2-acetamido- -glucopyranosyl)-(1/3)-
(2,4,6-tri-O-acetyl- -galactopyranosyl)-(1/4)-(2,3,6-tri-O-
acetyl- -glucopyranosyl)-(1/1)-(2S,3R,4E)-2-azido-3-O-
b-D-fucopyranosyl)-
40:1) to afford 18 (80 mg, 97%) as a white foam: Rf¼0.42 (ethyl
a-L
20
acetate/dichloromethane 2:1); [
a
]
ꢁ33.4 (c 1.0, chloroform); 1H
b-D
D
NMR (400 MHz, CDCl3):
d
5.38 (d, 1H, J¼7.7 Hz, NH), 5.33e5.29 (m,
b-D
2H), 5.28 (d, 1H, J¼3.7 Hz, H-1e), 5.26e5.23 (m, 2H, H-4b), 5.14 (t,
1H, J2,3¼J3,4¼9.3 Hz, H-3d), 5.08e5.06 (m, 1H, H-5d), 5.04 (d, 1H,
J1,2¼7.7 Hz, H-2a), 5.00e4.93 (m, 4H, H-2b, H-2e, H-6), 4.90 (d, 1H,
J1,2¼7.9 Hz, H-1c), 4.85 (dd, 1H, J1,2¼7.9 Hz, J2,3¼9.5 Hz, H-2d), 4.56
(d, 1H, J1,2¼7.8 Hz, H-1a), 4.44 (d, 1H, J1,2¼8.0 Hz, H-1d), 4.43e4.40
(m, 1H, H-6), 4.32 (d, 1H, J1,2¼7.9 Hz, H-1b), 4.24 (t, 1H, J3,4¼9.5 Hz,
H-3c), 4.12e4.00 (m, 3H, 2ꢃH-6), 3.98e3.93 (m, 1H, H-3e),
3.92e3.88 (m, 1H, OCHCH2Si), 3.81e3.72 (m, 4H, H-4c, H-4d, H-4e,
H-5e), 3.68 (dd, 1H, J2,3¼10.0 Hz, J3,4¼3.6 Hz, H-3b), 3.59e3.50 (m,
2H, OCHCH2Si), 3.41e3.37 (m, 1H, H-5c), 3.09e3.07 (m, 1H, H-2c),
2.17e1.91 (m, 42H, 14ꢃCH3CO), 1.38 (d, 3H, J5,6¼6.4 Hz, H-6e), 1.19
(d, 3H, J5,6¼6.6 Hz, H-6d), 0.97e0.82 (m, 2H, OCH2CH2Si), 0.02 (s,
b-D
benzoyl-4-octadecene-l,3-diol (20)
A solution of 19 (83 mg, 0.054 mmol, 1 equiv) and 3-O-benzoyl-
azido sphingosine 6 (46.6 mg, 0.108 mmol, 2 equiv) in 3.2 mL of dry
dichloromethane was stirred with 4 Å powdered molecular sieves
(200 mg) for 30 min at room temperature under nitrogen. BF3$Et2O
(39
m
L, 0.308 mmol, 5.7 equiv) was added dropwise at ꢁ10 ꢀC. The
mixture was stirred for 3 h at ꢁ10 ꢀC and then filtered through Celite.
The filtrate was washed with a saturated aqueous NaHCO3 and then
with water, dried over MgSO4 and concentrated. The residue was
applied to a flash chromatography eluted with cyclohexane/ethyl
9H, SiMe3). 13C NMR (100.6 MHz, CDCl3):
d
171.34, 171.14, 170.91,
acetate (1:1) to give the product 20 (55 mg, 57%) as an amorphous
20
170.80, 170.74, 170.62, 170.44, 170.24, 170.01, 169.79, 169.67, 169.46,
168.97 (14ꢃCH3CO), 100.81 (C-1b), 100.39 (C-1a), 100.10 (C-1d),
99.23 (C-1c), 95.53 (C-1e), 75.92, 75.86, 74.46, 73.24, 72.93, 72.73,
72.54, 71.81, 71.63, 71.31, 71.22, 71.20, 70.30, 70.10, 69.31, 69.24,
69.03, 68.02, 64.14 (19ꢃring C), 67.58 (OCH2CH2Si), 62.35, 61.61,
59.86 (3ꢃC-6), 58.80 (C-2c), 23.54e20.67 (14ꢃCH3CO), 17.98
(CH2Si), 16.02 (C-6e), 15.82 (C-6d), ꢁ1.33 (SiMe3). ESI-HRMS (m/z)
calcd for C63H93NO37SiNa (MþNaþ): 1506.5088. Found: 1506.5110.
solid: Rf¼0.42 (cyclohexane/ethyl acetate 1:2); [
a
]
ꢁ29.5 (c 1.0,
D
chloroform); 1H NMR (400 MHz, CDCl3):
d
8.04e8.02 (m, 2H, 2ꢃarom
H), 7.59e7.54 (m, 1H, arom H), 7.44 (t, 2H, J¼7.8 Hz, 2ꢃarom H), 5.90
0
(dt,1H, J5,6¼6.8 Hz, J4,5¼J5,6 ¼14.2 Hz, H-5), 5.60e5.49 (m, 2H, H-3, H-
4), 5.40 (d, 1H, J¼7.6 Hz, NHAc), 5.34e5.33 (m, 1H), 5.28 (d, 1H,
J¼3.8 Hz, H-1e), 5.26e5.24 (m, 3H), 5.15 (t, 1H, J¼9.3 Hz), 5.08e4.90
(m, 8H, H-1c, H-2a, H-2b, H-2d, H-3e, 2ꢃH-6), 4.58(d,1H, J¼7.8 Hz, H-
1a), 4.49 (d, 1H, J¼7.8 Hz, H-1b), 4.42 (d, 1H, J¼11.7 Hz, H-6), 4.33 (d,
1H, J¼7.9 Hz, H-1d), 4.27 (t,1H, J2,3¼J3,4¼9.3 Hz, H-3c), 4.12e3.90 (m,
5H, H-2, 3ꢃH-6), 3.86e3.74 (m, 5H, H-1, H-4c, H-5e), 3.70e3.67 (m,
1H), 3.60e3.54 (m, 2H, H-10), 3.40 (d, 1H, J¼9.8 Hz, H-5c), 3.07e3.05
(m, 1H, H-2c), 2.18e1.92 (m, 44H, 14ꢃCH3CO, CH2-6), 1.40 (d, 3H,
J5,6¼6.4 Hz, H-6e), 1.24e1.22 (m, 22H, 11ꢃCH2), 1.20 (d, 3H,
J5,6¼6.6 Hz, H-6d), 0.87 (t, 3H, J¼7.0 Hz, CH3). 13C NMR (100.6 MHz,
4.15. Synthesis of (2,3,4-tri-O-acetyl-
(1/4)-[2,3,4-tri-O-acetyl- -fucopyranosyl-(1/3)]-(6-O-
acetyl-2-deoxy-2-acetamido- -glucopyranosyl)-(1/3)-
(2,4,6-tri-O-acetyl- -galactopyranosyl)-(1/4)-2,3,6-tri-O-
acetyl- -glucopyranosyl trichloroacetimidate (19)
b-D-fucopyranosyl)-
a-L
b-D
b-D
a-D
CDCl3):
d 171.38, 171.17, 170.94, 170.82, 170.78, 170.54, 170.47, 170.28,
To a solution of compound 18 (124 mg, 0.084 mmol) in 2 mL of
dichloromethane was added 4 mL of trifluoroacetic acid dropwise at
0 ꢀC. The mixture was stirred at 0 ꢀC for 1 h and then at room tem-
perature for 5 h. Then the mixture was diluted with dichloromethane
and washed with a saturated aqueous NaHCO3 and then with brine,
dried over MgSO4. Afterconcentration, the residue was dried invacuo
(Rf¼0.3, dichloromethane/methanol 20:1). The residue was then
dissolved in 3.6 mL of dry dichloromethane, 0.3 mL of tri-
170.00, 169.81, 169.70, 169.64, 169.50, 169.00 (14ꢃCH3CO), 165.21
(PhC]O), 139.15 (C-5cer), 133.34 (arom CH), 130.07 (arom C), 129.87
(2ꢃarom CH), 128.59 (2ꢃarom CH), 122.77 (C-4), 100.93 (C-1d),
100.52 (C-1a), 100.42 (C-1b), 99.26 (C-1c), 95.55 (C-1e), 77.36, 75.86,
75.66, 74.40, 72.85, 72.72, 71.58, 71.42, 71.27, 71.20, 71.11, 70.27, 70.07,
69.28, 69.18, 69.05, 67.99 (17ꢃring C), 74.77 (C-3), 73.18 (C-5c), 72.39
(C-3c), 64.12 (C-2a), 63.58 (C-2), 68.47 (C-1), 62.06, 61.58, 59.70 (3ꢃC-
6), 58.87 (C-2c), 32.50 (C-6), 32.03, 29.79, 29.76, 29.70, 29.51, 29.47,
29.27, 28.82, 22.80 (11ꢃCH2), 23.58, 21.18e20.74 (14ꢃCH3CO), 16.02
(C-6e), 15.83 (C-6d), 14.26 (CH3). ESI-HRMS (m/z) calcd for
C83H118N4O39Na (MþNaþ): 1817.7265. Found: 1817.7218.
chloroacetonitrile was added to the solution and then 30 mL of DBU
was added dropwise at 0 ꢀC under nitrogen. The mixture was stirred
at 0 ꢀC for 4 h. After concentration, the residue was purified by flash
column chromatography (ethyl acetate/dichloromethane/triethyl-
amine10:10:0.01)toaffordcompound19 aswhitefoam(83 mg,65%):
4.17. Synthesis of (2,3,4-tri-O-acetyl-
(1/4)-[2,3,4-tri-O-acetyl- -fucopyranosyl-(1/3)]-(6-O-
acetyl-2-deoxy-2-acetamido- -glucopyranosyl)-(1/3)-
(2,4,6-tri-O-acetyl- -galactopyranosyl)-(1/4)-(2,3,6-tri-O-
acetyl- -glucopyranosyl) -(1/1)-(2S,3R,4E)-2-
b-D-fucopyranosyl)-
Rf¼0.36 (ethyl acetate/dichloromethane 2:1); [
a
]
20 þ2.6 (c 0.7, chlo-
a-L
D
roform); 1H NMR (400 MHz, CDCl3):
d
8.64 (s,1H, HN]C), 6.46 (d,1H,
b-D
J¼3.7 Hz, H-1a), 5.51 (t, 1H, J2,3¼J3,4¼9.7 Hz, H-3a), 5.44 (d, 1H,
J¼7.7 Hz, NHAc), 5.29e5.26(m, 2H, H-4e),5.28(d,1H, J¼3.8 Hz,H-1e),
5.24e5.23 (m, 1H, H-4d), 5.07 (d, 1H, J1,2¼7.8 Hz, H-2b), 5.03 (d, 1H,
J1,2¼3.3 Hz, H-2a), 5.02e4.91 (m, 6H, H-1c, H-2d, H-3e, H-5d, H-6),
4.57(d, 1H, J1,2¼7.8 Hz, H-1b), 4.44e4.40 (m, 1H, H-6), 4.35 (d, 1H,
J¼7.9 Hz, H-1d), 4.25 (t,1H, J2,3¼J3,4¼9.2 Hz, H-3c), 4.15e3.92 (m, 5H,
b-D
b-D
octadecanamido-3-O-benzoyl-4-octadecene-l,3-diol (21)
To a solution of compound 20 (32 mg, 0.018 mmol) in 4 mL of
toluene and 0.16 mL of water was added 18.8 mg of triphenyl

7382
Y. Zhang et al. / Tetrahedron 66 (2010) 7373e7383
phosphine. The mixture was stirred at 45 ꢀC for 24 h. After con-
centration, the residue was used directly for the next step.
Rf¼0.42 (dichloromethane/methanol 15:1). The mixture of the
residue, stearic acid (19 mg, 0.066 mmol), EDC (12.6 mg, 0.066
mmoL) in 4 mL of dichloromethane was stirred at room tem-
perature for 24 h. Then the mixture was washed with water,
dried over MgSO4 and concentrated. The residue was purified by
flash chromatography (dichloromethane/methanol 50:1) to give
d
175. 92, 174.62 (2ꢃC]O), 135.10 (C-5cer), 131.37 (C-4cer), 105.01,
104.48, 103.81, 103.72 (4ꢃC-1), 100.37 (C-1e), 83.85, 80.35, 77.24,
76.68, 76.62, 76.48, 76.25, 75.02, 74.98, 74.82, 73.72, 72.98, 72.66,
72.52, 71.74, 71.48, 71.22, 70.16, 69.78, 67.67 (19ꢃring C, C-3cer),
69.91 (C-1cer), 62.42, 61.75, 61.19 (3ꢃC-6), 57.70 (C-2c), 54.68 (C-
2cer), 37.37 (HNCOCH2), 33.47 (C-6cer), 27.16 (HNCOCH2CH2),
30.88e30.43, 23.74 (25ꢃCH2), 23.18 (NHCOCH3), 17.14 (C-6e), 16.63
(C-6d), 14.45 (2ꢃCH3). ESI-HRMS (m/z) calcd for C68H124N2O26Na
(MþNaþ): 1407.8335. Found: 1407.8319.
21 as an amorphous solid (22 mg, 61% for two steps): Rf¼0.51
20
(ehtyl acetate/dichloromethane 3:1); [
a
]
ꢁ22.2 (c 1.0, chloro-
D
form); 1H NMR (400 MHz, CDCl3):
d
8.00e7.40 (m, 5H, 5ꢃarom
Acknowledgements
0
H), 5.85 (dt, 1H, J5,6¼6.8 Hz, J4,5¼J5,6 ¼14.8 Hz, H-5cer), 5.73 (d,
1H, J¼9.2 Hz, NH-cer), 5.52 (t, 1H, J3,4¼J2,3¼7.3 Hz, H-3cer), 5.44
(dd, 1H, J3,4¼7.6 Hz, J4,5¼15.2 Hz, H-4cer), 5.38 (d, 1H, J¼7.7 Hz,
NHAc), 5.33e5.23 (m, 5H, H-1e), 5.13 (t, 1H, J3,4¼J2,3¼9.3 Hz, H-
3a), 5.08e5.04 (m, 2H, H-2d), 5.01e4.95 (m, 2H), 4.94e4.85 (m,
4H, H-1c, H-2a, H-3e, H-6c), 4.57 (d, 1H, J1,2¼7.8 Hz, H-1d),
4.49e4.44 (m, 1H, H-2cer), 4.42 (d, 1H, J1,2¼7.8 Hz, H-1a),
4.30e4.21(m, 3H, H-1b, H-3c, H-6a), 4.08e3.94 (m, 5H, H-1cer,
4ꢃH-6), 3.82e3.66 (m, 5H, H-2b, H-2e, H-4a, H-4c, H-5e), 3.60
We thank the China Scholarship Council for a Ph.D. fellowship to
Y.Z. Financial supports from the Centre National de la Recherche
Scientifique (CNRS) and the University Pierre et Marie Curie
(UPMC) are gratefully acknowledged.
Supplementary data
Supplementary data associated with this article can be found in
online version at doi:10.1016/j.tet.2010.07.025. This data include
MOL files and InChIKeys of the most important compounds de-
scribed in this article.
(dd, 1H, J1 ,2¼4.5 Hz, Jgem¼10.0 Hz, H-10cer), 3.54e3.50 (m, 1H, H-
0
0
5a), 3.39 (dt, 1H, J4,5¼J5,6¼2.2 Hz, J5,6 ¼9.8 Hz, H-5c), 3.10e3.04
(m, 1H, H-2c), 2.17e1.91 (m, 46H, 14ꢃCH3CO, CH2-6cer,
HNCOCH2), 1.59e1.56 (m, 2H, HNCOCH2CH2), 1.39 (d, 3H,
J5,6¼6.5 Hz, H-6e), 1.24e1.21 (m, 53H, 25ꢃCH2, H-6d), 0.86 (t, 6H,
References and notes
J¼7.0 Hz, 2ꢃCH3). 13C NMR (100.6 MHz, CDCl3):
d 172. 83, 171.37,
171.15, 170.93, 170.81, 170.76, 170.50, 170.47, 170.27, 169.90,
169.78, 169.69, 169.48, 168.98 (14ꢃCH3CO), 165.31 (PhC]O),
137.72 (C-5cer), 133.16 (arom CH), 130.38 (arom C), 129.72
(2ꢃarom CH), 128.52 (2ꢃarom CH), 124.75 (C-4cer), 100.82 (C-
1d), 100.49 (C-1a), 100.40 (C-1b), 99.24 (C-1c), 95.54 (C-1e),
75.85, 75.53, 74.45, 73.25, 72.91, 72.54, 72.47, 71.79, 71.63, 71.32,
71.26, 71.14, 70.31, 70.11, 69.32, 69.25, 69.05, 68.03, 64.16
(19ꢃring C), 74.18 (C-3cer), 67.57 (C-1cer), 62.09, 61.62, 59.83
(3ꢃC-6), 58.80 (C-2c), 50.76 (C-2cer), 36.97 (NHCOCH2), 32.45
(CH2-6cer), 25.85 (HNCOCH2CH2), 32.03, 29.82e29.06, 22.80
(25ꢃCH2), 23.56, 21.14e20.68 (14ꢃCH3CO), 16.03 (C-6e), 15.83 (C-
6d), 14.22 (CH3). ESI-HRMS (m/z) calcd for C101H154N2O40Na
(MþNaþ): 2057.9970. Found: 2057.9904.
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fucopyranosyl-(1/3)]-(2-deoxy-2-acetamido-
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b
-
D
-fucopyranosyl)-(1/4)-[
a
-
-
L
-
b
-
D
b
-D
-galactopyranosyl)-(1/4)-(
b-
D-
glucopyranosyl)-(1/1)-(2S,3R,4E)-2-octadecanamido-4-
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resin. After filtration and concentration, the residue was purified on
a Sephadex column (LH-20) using dichloromethane/methanol 1:1
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20
[
a]
ꢁ14.5 (c 0.4, MeOH); 1H NMR (400 MHz, CD3OD):
d 5.69 (dt,
D
0
1H, J5,6¼6.7 Hz, J4,5¼J5,6 ¼15.0 Hz, H-5cer), 5.45 (dd, 1H, J3,4¼7.7 Hz,
J4,5¼15.3 Hz, H-4cer), 5.04 (d, 1H, J¼3.9 Hz, H-1e), 4.92 (dd, 1H,
J5,6¼6.6 Hz, H-5d), 4.71 (d, 1H, J¼7.6 Hz, H-1), 4.41 (d, 1H, J¼7.1 Hz,
H-1), 4.37 (d,1H, J¼7.6 Hz, H-1), 4.30 (d, 1H, J¼7.8 Hz, H-1), 4.18 (dd,
1H, J¼4.4, 10.1 Hz, H-1cer), 4.09e4.05 (m, 2H, H-1cer, H-3cer),
4.01e3.95 (m, 2H, H-2cer), 3.92e3.84 (m, 7H, H-2c, 2ꢃH-6),
3.83e3.75 (m, 2H), 3.70 (dd, 1H, J5,6¼4.6 Hz, Jgem¼11.4 Hz, H-6),
3.64e3.50 (m, 9H, H-5e, 3ꢃH-6), 3.48e3.46 (m, 2H), 3.44e3.40 (m,
2H), 2.17 (t, 2H, J¼7.5 Hz, HNCOCH2), 2.05e2.00 (m, 2H, CH2-6cer),
1.98 (s, 3H, NHCOCH3), 1.60e1.57 (m, 2H, HNCOCH2CH2), 1.29 (s,
50H, 25ꢃCH2), 1.26 (d, 3H, J¼6.4 Hz, H-6e), 1.18 (d, 3H, J¼6.6 Hz, H-
6d), 0.90 (t, 6H, J¼6.8 Hz, 2ꢃCH3). 13C NMR (100.6 MHz, CD3OD):
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