A new one-pot synthesis of α-Gal epitope derivatives involved in the hyperacute rejection response in xenotransplantation

Article abstract of DOI:10.1016/j.tet.2005.02.023

Xenotransplantations from pig to human are rapidly rejected because of the interaction between α-Gal epitopes carried by the graft and natural antibodies (anti-Gal antibodies) present in the blood of the recipient. This paper describes a three-component o

Full text of DOI:10.1016/j.tet.2005.02.023

Tetrahedron 61 (2005) 4313–4321
A new one-pot synthesis of a-Gal epitope derivatives involved in
the hyperacute rejection response in xenotransplantation
*
Yuhang Wang, Qingyan Yan, Jingping Wu, Li-He Zhang and Xin-Shan Ye
The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University,
Xue Yuan Rd #38, Beijing 100083, China
Received 5 November 2004; revised 31 January 2005; accepted 3 February 2005
Available online 16 March 2005
Abstract—Xenotransplantations from pig to human are rapidly rejected because of the interaction between a-Gal epitopes carried by the
graft and natural antibodies (anti-Gal antibodies) present in the blood of the recipient. This paper describes a three-component one-pot
synthesis of three a-Gal related oligosaccharides with minimal protecting group manipulations in a very short period of time.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
enzymatic approach to synthesize various a-Gal derivatives
including trisaccharide and pentasaccharide epitopes based
on the use of recombinant a(1–3)-galactosyltransferase.6
Boons et al. reported a highly convergent synthesis of the
methyl glycoside of the pentasaccharide.7 And a direct
synthesis of ceramide pentasaccharide based on the
trichloroacetimidate methodology was carried out by the
Schmidt group.8 In the synthetic process of these oligo-
saccharides, the necessary regio- and stereocontrol often led
to laborious synthetic transformations, tremendous protect-
ing group manipulations, and tedious intermediate iso-
lations which complicated the overall synthetic process and
decreased synthetic efficiency. Herein we present a new
method for the synthesis of two trisaccharides 1 and 2, and
a pentasaccharide 3 (Scheme 1) using a three-component
one-pot strategy.9 The aminopropyl group was incorporated
as a side chain for further derivation.10 We envisaged
that the incorporation of the one-pot strategy with no
intermediate work-up or purification may simplify this
Nowadays the major barrier to a successful pig-to-human
xenotransplantation is antibody- and complement-depen-
dent hyperacute rejection (HAR),1 known to be due to the
specific interaction of recipient xenoreactive antibodies
with antigens present on the endothelium of the donor
organ, followed by activation of the complement cascade.2
It has been identified that trisaccharides Gala1-3Galb1-
4Glcb-R and Gala1-3Galb1-4GlcNAcb-R and penta-
saccharide Gala1-3Galb1-4GlcNAcb1-3Galb1-4Glcb-R
are the main a-Gal epitopes, which show high affinity
with xenoreactive natural antibodies (XNAs) in human
sera.3 In order to prevent the hyperacute rejection,
elimination or reduction of the interaction between a-Gal
and anti-Gal have been studied by various approaches
including anti-Gal immunoadsorption and anti-Gal neutral-
ization.4 Furthermore, a-Gal epitopes could be covalently
attached to certain antiviral agents through appropriate
linkers. The a-Gal-conjugated antiviral agents are envi-
saged to bind virus with a-Gal epitopes, resulting in the
killing of the virus via antibody-mediated cytotoxicity
and/or antibody-dependent, complement-mediated lysis of
virus particles and virus-infected cells.5 Such approaches
would require access to a substantial amount of a-Gal
oligosaccharides and a-Gal analogues.
Several methods were reported for the synthesis of a-Gal
epitope oligosacchrides. Wang et al. described a chemo-
Keywords: a-Galactosyl epitopes; One-pot synthesis; Glycosylations;
Oligosaccharides; Xenotransplantation.
*
Corresponding author. Tel.: C86 108 2801570; fax: C86 10 62014949;
e-mail: xinshan@bjmu.edu.cn
Scheme 1. The structures of a-Gal oligosaccharide derivatives 1, 2, 3.
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.02.023

4314
Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
complicated synthetic operation and improve the synthetic
efficiency.
the design of the in-between building blocks, because the
presence of a free hydroxyl group and thiotoluene
functionality would make it act as both a glycosyl acceptor
and donor. Besides, their relative reactivities towards
glycosylation should fall between non-reducing and redu-
cing end component. To charge these building blocks with
different reactivities, different protecting groups were used
according to the reactivity order of thioglycosides based on
the method which Wong group developed.9a,c Thus four
functional building blocks 7, 8, 9, and 10 were designed and
synthesized for one-pot glycosylation of the two trisac-
charides 4 and 5. As for the one-pot synthesis of
pentasaccharide 6, building blocks 11 and 13 were used as
non-reducing and reducing end unit, respectively. We
designed three building blocks 12, 14 and 15 for the choice
of the in-between component of 6, and it was demonstrated
that only 12 was suitable for the one-pot synthesis by
experiments.
2. Results and discussion
The initial design of building blocks and selection of
protecting groups were the key step in our one-pot synthesis.
The retrosynthetic analysis of a-Gal derivatives 1, 2, 3 is
shown in Scheme 2. Fully protected trisaccharides 4 and 5
could both be divided into three units: a non-reducing end
galactosyl, a hydroxy bridging galactosyl, and a side chain
binding glucosyl or glucosaminyl unit. The fully protected
pentasaccharide 6 was retrosynthetically disconnected into
three saccharide building blocks: disaccharide building
block 11, glucosaminyl building block 12, and lactosyl
building block 13. Implementation of one-pot oligosacchar-
ide synthesis requires a descending order of reactivity for
the three building blocks in each one-pot reaction. The non-
reducing end unit should have the highest reactivity among
the three components, and the reducing end component
should have no reactivity due to its O-glycoside which
cannot be activated by thioglycoside promoters. The
selection of protecting groups was the main concern in
We chose thioglycosides as glycosyl donors due to the
advantage that they are stable enough in most conditions
and can be activated by a variety of promoters. In order to
perform an efficient one-pot synthesis, we have tested
several promoter systems, such as dimethyl(thiomethyl)sul-
fonium triflate (DMTST),11 N-iodosuccinimide and triflic
acid (NIS/TfOH),12 phenylsulfenyl chloride and silver
triflate (PhSCl/AgOTf),13 1-benzenesulfinyl piperidine and
triflic anhydride (BSP/Tf2O).14 Eventually we found that
NIS/TfOH was a suitable promoter for trisaccharide
synthesis and BSP/Tf2O was an efficient coupling agent
for pentasaccharide synthesis.
2.1. Synthesis of building blocks
Building blocks 7 and 8 were prepared by literature
procedures.9a The synthesis of glucosyl acceptor 9 was
performed as depicted in Scheme 3. The synthesis was
started from glucose pentaacetate, which was converted to
the b-glucoside 16 by the reaction with benzyl N-(3-
hydroxypropyl)-carbamate in the presence of BF3$Et2O.
Deacetylation of 16 followed by 4,6-O-benzylidene protec-
tion produced saccharide 17. The benzylation of the two
remaining hydroxyls of 17 was performed using sodium
hydride and benzyl bromide in DMF to give compound 18.
Subsequent selectively reductive cleavage of 4,6-O-benzyl-
idene acetal of 18 gave the 4-OH exposed saccharide 9 in
88% yield.
Scheme 3. (a) HO(CH2)3NHCbz, BF3$Et2O, CH2Cl2, rt, 41%; (b) (i)
NaOMe/MeOH, rt; (ii) PhCH(OMe)2, CSA, CH3CN, rt, 66%; (c) BnBr/
NaH/DMF, 0 8C to rt, 97%; (d) HCl$Et2O/NaCNBH3/THF, rt, 88%.
Scheme 2. The retrosynthetic analysis of one-pot synthesis of a-Gal
derivative 1, 2, 3.

Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
4315
The preparation of building block 14 and 15 is summarized
in Scheme 6. The synthesis was started from p-methyl-
phenyl 3,4,6-tri-O-acetyl-2-deoxy-2-(2,2,2-trichloroethoxyl-
carbonylamino)-1-thio-b-D-glucopyranoside,9a which was
deacetylated by using NaOMe/MeOH, followed by the
p-methoxylbenzylidene formation between C4/C6 hydroxyls
to produce compound 21. The remaining C3 hydroxyl of 21
was converted to a benzoyl ester, giving fully protected
thioglycoside 22. Subsequent selective cleavage of 4,6-O-
methoxylbenzylidene acetal of 22 gave 6-O-methoxylben-
zyl ether 14 in 80% yield. Compound 23 was produced by
removal of the p-methoxylbenzylidene protecting group,
followed by the selective protection of C6 hydroxyl by tert-
butyldiphenylsilyl (TBDPS) group, yielding building block
15 in 86% yield.
Scheme 4. (a) BnBr/NaH/DMF, 0 8C to rt, 92%; (b) HCl$Et2O/NaCNBH3/
˚
THF, rt, 90%. (c) HO(CH2)3NHCbz/NIS/TfOH, CH2Cl2, 4 A MS, 0 8C,
49%; (d) HCl$Et2O/NaCNBH3/THF, rt, 91%.
The synthesis of building blocks 10 and 12 was shown in
Scheme 4. Benzylation of p-methylphenyl 4,6-O-benzyli-
dene-2-deoxy-2-phthalimido-1-thio-b-D-glucopyranoside9a
gave saccharide 19 in 92% yield. Regioselective reductive
ring-opening of 4,6-O-benzylidene acetal of 19 produced 12
in 90% isolated yield with the 4-hydroxyl group exposed.15
And the coupling reaction between compound 19 and
benzyl N-(3-hydroxypropyl)-carbamate was promoted by
NIS/TfOH, producing compound 20, followed by the same
regioselective ring-opening reaction to give building block
10 (91% yield).
Building block 11 was synthesized by glycosylation
between perbenzylated galactosyl thioglycoside donor 7
and galactosyl acceptor 8 (Scheme 5). We chose the donor
and acceptor according to their relative reactivity values
(RRV) measured by the Wong group.9c The large disparity
of the reactivity between 7 and 8 (RRV of 7Z5.2!104,
RRV of 8Z1791) enables the high sequence selectivity of
glycosidic coupling reaction. Much attention was paid to
the choice of the glycosylation conditions. At first, we used
DMTST11 and NIS/TfOH12 as promoters, respectively.
However, the use of DMTST required a harsh condition.
The operation inconvenience limited its use in this
glycosylation reaction. In the presence of NIS/TfOH (1.1
or 1.2 equiv), donor 7 was coupled with acceptor 8 to give
the target disaccharide 11 in moderate yield (54%),
attributed to the formation of byproducts. Two possible
byproducts could have formed. One is the succinimide
product,9a the other is the hydrolyzed product due to the fact
that the anomeric thiotoluene functionality of compound 11
could be further activated by the excessive NIS/TfOH and
substituted by hydroxyl group after work-up with water.
Finally, we turned our attention to BSP/Tf2O,14b developed
by Crich and Smith,14a in order to improve the efficiency of
the glycosylation protocol. Utilizing BSP/Tf2O as the
promoter system, the coupling reaction of 7 and 8 proceeded
smoothly, and the desired product was isolated in 90%
yield.
Scheme 6. (a) (i) NaOMe/MeOH, rt; (ii) p-CH3OPhCH(OMe)2, CSA,
CH3CN, rt, 90%; (b) BzCl, pyridine, 0 8C, 83%; (c) CF3COOH/
˚
NaCNBH3/DMF, 4 A MS, rt to 40 8C, 80%; (d) HOAc, rt, 91%;
(e) TBDPSCl, imidazole, DMF, rt, 86%.
The synthesis of building block 13 began with lactose
peracetate, which was converted to the b-lactoside 24 by
reaction with benzyl N-(3-hydroxypropyl)-carbamate in the
presence of BF3$Et2O. Compound 24 was deacetylated by
using NaOMe/MeOH, then treated with dibutyltin oxide,
followed by the reaction with allyl bromide to provide
selective 30-O-allyl protected lactoside 25. The following
benzylation of the remaining hydroxyls of 25 was
performed using sodium hydride and benzyl bromide in
DMF to give compound 26. And building block 13 was
prepared by removal of the allyl protecting group of 26
using palladium (II) chloride (Scheme 7).15
Scheme 7. (a) HO(CH2)3NHCbz, BF3$Et2O, CH2Cl2, rt, 43%; (b) (i)
NaOMe/MeOH, rt; (ii) MeOH/Bu2SnO, 110 8C; then CH2]CH–CH2–Br,
˚
Bu4NI, C6H6, 120 8C, 4 A MS; (c) BnBr/NaH/DMF, 0 8C, 70% from 24 to
26; (d) PdCl2, MeOH, rt, 98%.
˚
Scheme 5. (a) BSP, Tf2O, CH2Cl2, 4 A MS, K70 8C to rt, 90% or NIS,
˚
TfOH, CH2Cl2, 4 A MS, 0 8C, 54%.

4316
Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
2.2. The one-pot synthesis of fully protected a-Gal
derivatives 4, 5, 6 and the preparation of their
deprotected products 1, 2, 3
of the promoter systems. This is possibly because of the
steric hindrance of the bulky group TBDPS and the
electron-withdrawing effect of Bz group which decreased
the activity of the 4-OH, and also because the PMB ether is
sensitive to acid while the coupling condition we used are
all slightly acidic.
With all building blocks in hand, we began to assemble the
three target oligosaccharides using a two-step three-
component one-pot coupling protocol. The synthesis of
the two trisaccharides was depicted in Scheme 8. The more
reactive building block 7 was first activated in the presence
of NIS/TfOH at 0 8C to couple with the less reactive
building block 8 and the reaction was monitored by TLC.
After complete consumption of donor 7 the third building
block 9 along with another molar equivalent of NIS was
then added. The resulting trisaccharide 4 was obtained in
55% isolated yield. The synthesis of 5 was identical with
that of 4 except that the final acceptor used was building
block 10. Trisaccharide 5 was obtained also in 55% isolated
yield. The yield of the two trisaccharides is higher than that
of the disaccharide 11 (54%). This is presumably because
that the O-functionality in the reducing end of the
trisaccharides is innate to the thioglycoside promoters,
which cannot undergo the byproduct formation process as
disaccharide 11 (vide supra). Complete deprotection of 4
was involved in two steps: the benzoyl group was removed
by NaOMe/MeOH, and the benzyl, benzylidene, and benzyl
carbamate protecting groups were cleaved by catalytic
hydrogenolysis over 10% Pd–C to give trisaccharide 1
(in the form of acetate) in 70% isolated yield. Full
deprotection of 5 was accomplished as follows:7 the
phthalimido group was converted into an NHAc moiety
by treatment with NH2NH2$H2O followed by reacetylation
with acetic anhydride in pyridine, the benzoyl group was
removed by NaOMe/MeOH, the benzyl, benzylidene
and benzyl carbamate protecting groups were removed
with Pd–C catalyzed hydrogenolysis to afford trisaccharide
2 (in the form of acetate) in 70% isolated yield. The a, b
anomeric configurations of the two trisaccharides were
conformed by their 1H and 13C NMR spectra referred to the
structure of the pentasaccharide we reported recently.15
In view of the failure of glycosylation using N-Troc building
blocks, we turned to N-Phth building block 12. We
protected the 3-OH and 6-OH with benzyl group, which
we expected to improve the activity of the 4-OH. The
promoters mentioned above were also tried in this one-pot
synthesis and BSP/Tf2O promoted the glycosylation most
efficiently. For the BSP/Tf2O promoted one-pot opera-
tion,14b the donors must be activated at K70 8C and the
reaction temperature was increased gradually to room
temperature. The equivalent of BSP ranged from 0.5 to
1.0, and 0.5 equiv acted best. The first glycosylation
between the disaccharide donor 11 and the glucosaminyl
unit 12 was accomplished in 3 h to provide the trisaccharide
which subsequently reacted with the lactose acceptor 13
in the second glycosylation, giving the fully protected
pentasaccharide glycoside 6 (Scheme 9). The isolated yield
of this BSP/Tf2O promoted one-pot synthesis was 42%.
˚
Scheme 9. (a) BSP, Tf2O, CH2Cl2, 4 A MS, K70 8C to rt 42%; (b) (i)
NH2NH2$H2O, EtOH, reflux; (ii) Ac2O, pyridine; (iii) NaOMe, MeOH;
(iv) H2, Pd–C, HOAc/THF/H2O, 43%.
Global deprotection of 6 was performed in four steps7
(Scheme 9). The phthalimido functionality was removed
with NH2NH2$H2O in EtOH under reflux to release the
amino group and then was acetylated with acetic anhydride
in pyridine. The remaining benzoylate was cleaved by the
treatment with NaOMe in methanol. The benzyl, benzyl-
idene, and benzyl carbamate functionalities were depro-
tected by Pd–C catalyzed hydrogenolysis. The target
pentasaccharide 3 (in the form of acetate) was obtained in
43% isolated yield from 6. The characterization of 3 and the
correct anomeric configuration of each glycosidic linkage
˚
Scheme 8. (a) NIS, TfOH, CH2Cl2, 4 A MS, 0 8C, 55% for 4, 55% for 5;
1
(b) (i) NaOMe, MeOH; (ii) H2, Pd–C, HOAc/THF/H2O, 70%; (c) (i)
NH2NH2$H2O, EtOH, reflux; (ii) Ac2O, pyridine; (iii) NaOMe, MeOH;
(iv) H2, Pd–C, HOAc/THF/H2O, 70%.
were confirmed by its 1D H NMR, 13C NMR and 2D
correlations spectroscopy (HSQC, HMBC, TOCSY), and
HRMS analysis.15
For the one-pot synthesis of the pentasaccharide 3, we have
tried different building blocks and promoter systems, and
finally we found most suitable ones. To carry out the
glycosylation reaction, a variety of promoters (DMTST,
NIS/TfOH, PhSCl/AgOTf, BSP/Tf2O) were used. Never-
theless, when compound 14 or 15 was used as the second
building block, we found that even the first glycosylation
between 11 and 14 or 15 did not occur in the presence of any
3. Conclusion
In summary, we have successfully synthesized the amino-
propyl glycosides of two trisaccharides and a pentasac-
charide which play an important role in the interaction with
human anti-Gal antibodies. The protected oligosaccharides

Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
4317
were rapidly and efficiently synthesized by a one-pot
sequential glycosylation strategy. This one-pot strategy is
expected to be powerful in efficient synthesis of other a-Gal
derivatives and oligosaccharides.
was suspended in dry CH3CN (60 mL). Benzaldehyde
dimethyl acetal (1.0 mL, 1.0 g, 6.61 mmol) and (G)-10-
camphorsulfonic acid (0.1 g, 0.44 mmol) were added to the
mixture. The reaction mixture was stirred for 5 h, then
neutralized with triethylamine. The solvent was removed
under reduced pressure. The residue was purified by column
chromatography on silica gel (petroleum ether/EtOAcZ
4. Experimental
1
1:1), yielding a white glassy solid (1.7 g, 66%). H NMR
(500 MHz, DMSO-d6) d: 7.24–7.45 (m, 10H, aromatic),
5.57 (s, 1H, benzylidene-CH), 5.29 (dd, JZ5.0, 13.5 Hz,
1H), 5.01 (br.m, 2H), 4.32 (d, JZ8.0 Hz, 1H), 4.17 (dd, JZ
3.5, 10.0 Hz, 1H), 3.73 (dt, JZ10.0, 5.0 Hz, 1H), 3.66–3.70
(m, 1H), 3.49 (dt, JZ9.0, 4.5 Hz, 1H), 3.16–3.20 (m, 6H),
3.09–3.06 (m, 2H), 1.70–1.65 (m, 2H, OCH2CH2CH2N);
13C NMR (125 MHz, DMSO-d6) d: 156.1 (NCOO), 137. 8,
137.2, 128.8, 128.4, 128.0, 127.8, 126.3 (aromatics), 103.4,
100.6, 80.6, 74.3, 72.8, 68.0, 66.8, 65.8, 65.2, 37.5
(OCH2CH2CH2N), 29.6 (OCH2CH2CH2N); FAB-MS
(MCH)C 460. Anal. Calcd for C24H29O8N: C, 62.73; H,
6.36; N, 3.05. Found: C, 62.55; H, 6.38; N, 2.83.
4.1. General method
All chemicals were purchased as reagent grade and used
without further purification. Dichloromethane and aceto-
nitrile were distilled over CaH2. Benzene was distilled over
sodium/benzophenone. Methanol was distilled from mag-
nesium. DMF was stirred with CaH2 and distilled under
reduced pressure. Reactions were monitors with analytical
thin-layer chromatography on silica gel 60 F254 plates,
detected under UV (254 nm) and by staining with acidic
ceric ammonium molybdate. Column chromatography was
performed on silica gel (200–300 mesh). H NMR and 13C
1
NMR spectra were recorded on 300 MHz Varian VXR and
500 MHz Varian INOVA spectrometer. Chemical shift
(in ppm) was determined relative to tetramethylsilane in
deuterated chloroform (dZ0 ppm). Coupling constant are
given in Hz. Mass spectra were recorded using a PE SCLEX
QSTAR spectrometer. And elemental analysis data were
recorded on PE-2400C elemental analyzer.
4.1.3. (3-Benzyl-3-benzyloxycarbonylamino)propyl 2,3-
di-O-benzyl-4,6-O-benzylidene-b-D-glucopyranoside
(18). Compound 17 (1.6 g, 3.53 mmol) and sodium hydride
(0.36 mg, 14.12 mmol) were stirred in DMF (30 mL) at 0 8C
for 10 min and benzyl bromide (1.7 mL, 2.4 g, 14.12 mmol)
was added. The mixture was stirred at room temperature
overnight and then poured into ice water (30 mL), which
was extracted with EtOAc (3!30 mL), then dried
(Na2SO4). The organic phase was concentrated for column
chromatography on silica gel (petroleum ether/EtOAcZ
4:1). Compound 18 (2.5 g, 97%) was obtained as a yellow
4.1.1. (3-Benzyloxycarbonylamino)propyl 2,3,4,6-tetra-
O-acetyl-b-D-glucopyranoside (16). Glucose pentaacetate
(7.0 g, 0.018 mol) and benzyl N-(3-hydroxypropyl)-carba-
mate (4.5 g, 0.022 mol) were stirred in dry CH2Cl2
(100 mL) and BF3$Et2O (15.3 mL, 15.3 g, 0.108 mol) was
added. The reaction mixture was stirred at room temperature
for 8 h and then diluted with CH2Cl2 (100 mL), washed
sequentially with satd aq NaHCO3 and brine, dried
(Na2SO4), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ1:1). The product (3.9 g, 41%) was obtained
as a yellow syrup. 1H NMR (300 MHz, CDCl3) d: 7.20–7.29
(m, 5H, aromatic), 5.15–5.20 (m, 1H), 5.10 (t, JZ9.6 Hz,
1H), 4.91–5.02 (m, 3H), 4.87 (dd, JZ8.1, 9.3 Hz, 1H), 4.40
(d, JZ7.8 Hz, 1H), 4.14 (dd, JZ4.5, 12.3 Hz, 1H), 4.03
(dd, JZ2.4, 12.0 Hz, 1H), 3.80 (dt, JZ9.9, 5.4 Hz, 1H),
3.56–3.60 (m, 1H), 3.48 (dt, JZ9.3, 4.4 Hz, 1H), 3.0.–3.24
(m, 2H), 1.97 (s, 3H, COCH3), 1.94 (s, 3H, COCH3), 1.92
(s, 3H, COCH3), 1.89 (s, 3H, COCH3), 1.67–1.70 (m, 2H,
OCH2CH2CH2N); 13C NMR (75 MHz, CDCl3) d: 170.5
(COCH3), 170.0 (COCH3), 169.2 (COCH3), 156.3 (NCOO),
136.4, 128.2, 127.8, 127.8 (aromatics), 100.4 (C-1), 72.5,
71.5, 71.0, 68.1, 67.3, 66.2, 61.6, 37.9 (OCH2CH2CH2N),
29.2 (OCH2CH2CH2N), 20.4 (COCH3), 20.4 (COCH3),
20.4 (COCH3); FAB-MS (MCH)C 540. Anal. Calcd for
C25H33O12N: C, 55.65; H, 6.16; N, 2.60. Found: C, 55.80;
H, 6.19; N, 2.30.
1
syrup. H NMR (500 MHz, DMSO-d6) d: 7.21–7.43 (m,
25H, aromatic), 5.66 (s, 1H, benzylidene-CH), 5.10 (br.s,
2H), 4.45–4.78 (m, 7H), 4.20 (m, 1H), 4.10 (q, JZ5.0 Hz,
1H), 3.68–3.76 (m, 4H), 3.38–3.54 (m, 2H), 3.28 (m, 2H),
1.76 (m, 2H, OCH2CH2CH2N); 13C NMR (125 MHz,
DMSO-d6) d: 155.8 (NCOO), 138.7, 138.4, 138.1, 137.6,
136.9, 128.7, 128.5, 128.4, 128.0, 127.8, 127.5, 127.4,
127.4, 127.3, 127.1, 127.0, 125.9 (aromatics), 102.9, 100.0,
81.6, 80.5, 80.1, 74.0, 73.7, 67.8, 67.0, 66.9, 66.4, 65.2,
50.0, 28.4 (OCH2CH2CH2N); FAB-MS (MCH)C 730.
Anal. Calcd for C45H47O8N: C, 74.05; H, 6.49; N, 1.92.
Found: C, 73.91; H, 6.49; N, 1.76.
4.1.4. (3-Benzyl-3-benzyloxycarbonylamino)propyl
2,3,6-tri-O-benzyl-b-D-glucopyranoside (9). To a mixture
of compound 18 (2.4 g, 3.29 mmol), NaCNBH3 (2.7 g,
˚
0.041 mol), and 3 A MS (2.5 g) in dry THF (50 mL), was
added dropwise a solution of HCl–Et2O (66 mL, 1 M in
Et2O, 65.8 mmol) under N2 at room temperature. The
mixture was stirred for 10 min, then filtered off through
Celite. The filtrate was washed sequentially with satd aq
NaHCO3 and brine, dried (Na2SO4), filtered, and concen-
trated. The residue was purified by column chromatography
on silica gel (petroleum ether/EtOAcZ3:1). The product
1
4.1.2. (3-Benzyloxycarbonylamino)propyl 4,6-O-benzyl-
idene-b-D-glucopyranoside (17). To a stirred solution of 16
(3.0 g, 5.51 mmol) in methanol (50 mL), NaOMe (0.2 mL,
30% in MeOH, 0.55 mmol) was added. The reaction
mixture was stirred at room temperature for 5 h and then
neutralized with cation exchange resin (HC). The resin was
filtered off and the filtrate was concentrated. The residue
(2.1 g, 88%) was obtained as a yellow syrup. H NMR
(300 MHz, DMSO-d6) d: 7.23–7.32 (m, 25H, aromatic),
5.40 (d, JZ6.0 Hz, 1H, H-1), 5.09 (br.s, 2H), 4.36–4.82
(m, 10H), 4.07–4.12 (m, 2H), 3.71–3.75 (m, 2H), 3.29–3.55
(m, 4H), 1.70–1.80 (m, 2H, OCH2CH2CH2N); 13C NMR
(75 MHz, CDCl3) d: 156.6 (NCOO), 138.5, 138.3, 137.8,
137.7, 136.6, 129.6, 128.9, 128.5, 128.4, 128.4, 128.3,

4318
Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
128.2, 127.9, 127.8, 127.8, 127.7, 127.6, 127.6, 127.2
(aromatics), 103.4 (C-1), 83.9, 81.6, 76.2, 75.2, 74.6, 74.0,
73.5, 71.4, 70.1, 67.1, 58.2, 50.6, 28.6 (OCH2CH2CH2N);
FAB-MS (MCH)C 732. Anal. Calcd for C45H49O8N: C,
73.85; H, 6.75; N, 1.91. Found: C, 74.12; H, 6.87; N, 1.72.
(MCH)C 681. Anal. Calcd for C39H40O9N2: C, 68.81; H,
5.92; N, 4.12. Found: C, 68.80; H, 6.11; N, 3.76.
4.1.7. p-Methylphenyl 2-O-benzoyl-3-O-(2,3,4,6-tetra-O-
benzyl-a-D-galactopyranosyl)-4,6-O-benzylidene-1-thio-
b-D-galactopyranoside (11). Donor 79a (44.6 mg,
˚
0.069 mmol), BSP (12 mg, 0.063 mmol), and 4 A MS
4.1.5. (3-Benzyloxycarbonylamino)propyl 3-O-benzyl-
4,6-O-benzylidene-2-deoxy-2-phthalimido-b-D-gluco-
pyranoside (20). To a mixture of compound 1915 (100 mg,
0.17 mmol), benzyl N-(3-hydroxypropyl)-carbamate
(200 mg) were stirred in dry CH2Cl2 (2 mL) at room
temperature for 0.5 h under N2. The mixture was cooled to
K70 8C, followed by the addition of Tf2O (11.9 mL,
19.5 mg, 0.069 mmol). After 10 min, a solution of acceptor
89a (30 mg, 0.063 mmol) in dry CH2Cl2 (2 mL) was added
to the reaction mixture, and the temperature was increased
gradually to room temperature. After 2 h, the reaction was
quenched with triethylamine (2 mL) and diluted with
CH2Cl2 (10 mL). The reaction mixture was filtered and
washed sequentially with satd aq NaHCO3 and brine, dried
(Na2SO4), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ3:1). The product (56 mg, 90%) was
˚
(48.6 mg, 0.22 mmol), and 4 A MS (2.5 g) in dry CH2Cl2
(10 mL), were added NIS (39.5 mg, 0.18 mmol) and TfOH
(69 mL, 0.5 M in Et2O, 0.034 mmol) under N2 at 0 8C. After
stirred for 2 h, the mixture was neutralized with triethyl-
amine, then filtered off through Celite. The filtrate was
washed sequentially with satd aq NaHCO3 and brine, dried
(Na2SO4), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ1:1). The product (56 mg, 49%) was
1
obtained as a yellow solid. H NMR (500 MHz, DMSO-
1
obtained as a yellow syrup. H NMR (500 MHz, CDCl3)
d6) d: 7.71–7.92 (m, 4H, aromatic), 7.49 (d, JZ6.5 Hz, 2H,
aromatic), 7.26–7.49 (m, 7H, aromatic), 7.07 (t, JZ5.0 Hz,
1H, aromatic), 6.97 (t, JZ7.0 Hz, 1H, aromatic), 6.87–6.92
(m, 4H, aromatic), 5.77 (s, 1H, benzylidene-CH), 5.14 (d,
JZ8.5 Hz, 1H, H-1), 4.85 (br.s, 2H), 4.70 (d, JZ12.0 Hz,
1H), 4.40 (d, JZ12.5 Hz, 1H), 4.28–4.32 (m, 2H), 3.99 (dd,
JZ8.5, 10.5 Hz, 1H), 3.98 (t, JZ9.5 Hz, 1H), 3.85 (t, JZ
10.0 Hz, 1H), 3.67 (t, JZ10.0 Hz, 1H), 3.58 (dt, JZ4.5,
9.0 Hz, 1H), 3.34–3.42 (m, 2H), 3.12–3.20 (m, 1H), 2.76–
2.80 (m, 2H), 1.40–1.49 (m, 2H); 13C NMR (125 MHz,
DMSO-d6) d: 167.4 (Phth-CON), 155.9 (NCOO), 137.8,
137.6, 137.2, 134.7, 130.7, 128.9, 128.3, 128.2, 127.9,
127.7, 127.5, 127.4, 126.0, 123.4, 100.2, 98.3, 81.9, 74.6,
73.1, 67.8, 66.7, 65.7, 65.0, 55.4, 36.8, 29.4; FAB-MS (MC
H)C 679. Anal. Calcd for C39H38O9N2: C, 69.01; H, 5.64;
N, 4.13. Found: C, 68.95; H, 5.64; N, 3.92.
d: 7.96 (d, JZ8.0 Hz, 2H, aromatic), 7.41–7.45 (m, 3H,
aromatic), 7.34 (d, JZ7.5 Hz, 2H, aromatic), 7.02-7.27 (m,
23H, aromatic), 6.89 (d, JZ8.0 Hz, 2H, aromatic), 6.97 (d,
JZ8.0 Hz, 2H, aromatic), 5.49 (t, JZ9.5 Hz, 1H, H-2), 5.32
(s, 1H, benzylidene-CH), 4.98 (d, JZ3.0 Hz, 1H, H-10),
4.70 (d, JZ11.8 Hz, 1H), 4.65 (d, JZ9.5 Hz, 1H), 4.55 (d,
JZ12.0 Hz, 1H), 4.49 (d, JZ11.5 Hz, 1H), 4.39 (d, JZ
11.5 Hz, 1H), 4.35 (d, JZ12.0 Hz, 1H), 4.24–4.31 (m, 4H),
4.18 (d, JZ12.0 Hz, 1H), 3.84–3.94 (m, 3H), 3.74 (t, JZ
6.0 Hz, 1H), 3.55 (d, JZ10.0 Hz, 1H), 3.34 (d, JZ13.0 Hz,
2H), 3.05–3.20 (m, 2H), 2.26 (s, 3H, SPhCH3); 13C NMR
(125 MHz, CDCl3) d: 164.6 (CO), 138.8, 138.7, 138.5,
138.3, 138.1, 137.7, 134.2, 132.9, 130.1, 129.8, 129.5,
128.9, 128.3, 128.2, 128.1, 128.1, 128.0, 127.8, 127.7,
127.6, 127.5, 127.4, 127.3, 127.2, 126.6 (aromatics), 101.0,
94.6, 85.4, 78.6, 75.8, 75.5, 74.9, 74.6, 74.2, 73.1, 72.2,
71.8, 69.9, 69.8, 69.3, 69.0, 68.7, 21.2 (SPhCH3); TOF-MS
(MCNH4)C 1018. Anal. Calcd for C61H60O11S: C, 73.17;
H, 6.04. Found: C, 72.84; H, 6.17.
4.1.6. (3-Benzyloxycarbonylamino)propyl 3,6-di-O-ben-
zyl-2-deoxy-2-phthalimido-b-D-glucopyranoside (10). To
a mixture of compound 20 (0.44 g, 0.66 mmol), NaCNBH3
˚
(0.55 g, 8.25 mmol), and 3 A MS (2.5 g) in dry THF
4.1.8. p-Methylphenyl 4,6-O-p-methoxybenzylidene-2-
deoxy-2-(2,2,2-trichloroethoxylcarbonyl- amino)-1-thio-
b-D-glucopyranoside (21). To a stirred solution of
p-methylphenyl 3,4,6-tri-O-acetyl-2-deoxy-2-(2,2,2-tri-
chloroethoxylcarbonylamino)-1-thio-b-D-glucopyrano-
side9a (1.100 g, 1.9 mmol) in methanol (40 mL), NaOMe
(13 mL, 30% in MeOH, 0.37 mmol) was added. The reaction
mixture was stirred at room temperature for 6 h and then
neutralized with cation exchange resin (HC). The resin
was filtered off and the filtrate was concentrated. The
residue (white solid) was suspended in dry CH3CN (40 mL).
p-Methoxybenzaldehyde dimethyl acetal (0.63 mL,
685 mg, 3.74 mmol) and (G)-10-camphorsulfonic acid
(87 mg, 0.374 mmol) were added to the mixture. The
reaction mixture was stirred for 5 h then neutralized with
triethylamine. The solvent was removed by rotaevaporator.
The residue was purified by column chromatography on
silica gel (petroleum ether/EtOAcZ1:2), yielding a white
(50 mL), was added dropwise a solution of HCl–Et2O
(13.2 mL, 1 M in Et2O 13.2 mmol) under N2 at room
temperature. The mixture was stirred for 30 min, then
filtered off through Celite. The filtrate was washed
sequentially with satd aq NaHCO3 and brine, dried
(Na2SO4), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ3:1). The product (0.4 g, 91%) was obtained
as a yellow syrup. 1H NMR (300 MHz, DMSO-d6) d: 7.73–
7.85 (m, 4H, aromatic), 7.28–7.37 (m, 9H, aromatic), 7.07
(t, JZ5.7 Hz, 1H, aromatic), 6.86–6.94 (m, 5H, aromatic),
5.65 (d, JZ6.6 Hz, 1H), 5.03 (d, JZ11.4 Hz, 1H), 4.89
(br.s, 2H), 4.76 (d, JZ12.0 Hz, 1H), 4.57 (br.s, 2H), 4.41
(d, JZ12.3 Hz, 1H), 4.02–4.14 (m, 2H), 3.35–3.86
(m, 7H), 2.81 (q, JZ6.3 Hz, 2H), 1.41–1.53 (m, 2H,
OCH2CH2CH2N); 13C NMR (75 MHz, DMSO-d6) d: 167.6
(Phth-CON), 167.4 (Phth-CON), 155.9 (NCOO), 138.6,
138.3, 137.2, 134.6, 130.8, 128.3, 128.2, 127.8, 127.7,
127.4, 127.3, 127.1, 123.2 (aromatics), 97.6 (C-1),
78.6, 75.7, 73.5, 72.3, 71.6, 69.1, 66.4, 65.0, 55.2, 37.0
(OCH2CH2CH2N), 29.4 (OCH2CH2CH2N); FAB-MS
1
glassy solid (0.95 g, 90%). H NMR (300 MHz, CDCl3) d:
7.37–7.40 (m, 4H, aromatic), 7.14 (d, JZ8.1 Hz, 2H,
aromatic), 6.87 (d, JZ8.7 Hz, 2H, aromatic), 5.48 (s, 1H,
p-methyloxybenzylidene-CH), 5.28 (d, JZ6.0 Hz, 1H),

Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
4319
4.84 (d, JZ10.5 Hz, 1H), 4.82 (d, JZ12.0 Hz, 1H), 4.70 (d,
JZ12.0 Hz, 1H), 4.34 (dd, JZ4.2, 10.2 Hz, 1H), 3.90–4.05
(m, 1H), 3.78 (s, 3H), 3.71–3.75 (m, 1H), 3.39–3.48 (m,
2H), 2.97 (br.s, 1H), 2.34 (s, 3H, SPhCH3), 2.01 (d, JZ
3.0 Hz, 1H); 13C NMR (75 MHz, CDCl3) d: 160.3, 154.3,
138.7, 134.0, 133.5, 130.2, 129.9, 129.4, 127.7, 127.4,
113.8, 101.8, 86.7, 81.1, 74.7, 72.3, 70.3, 68.5, 55.3, 21.2;
MALDI-TOF-MS (MCH)C 578.
for C31H32Cl3NO8S: C, 54.36; H, 4.71; N, 2.04. Found: C,
54.27; H, 4.82; N, 2.00.
4.1.11. p-Methylphenyl 3-O-benzoyl-2-deoxy-2-(2,2,2-
trichloroethoxyl carbonylamino)-1-thio-b-D-gluco-
pyranoside (23). Compound 22 (40.8 mg, 0.06 mmol)
was stirred in acetic acid (80%, 2.0 mL) at room
temperature overnight. After removal of the solvent, the
residue was purified by column chromatography on silica
gel (petroleum ether/EtOAcZ1:1), yielding a colorless
4.1.9. p-Methylphenyl 3-O-benzoyl-4,6-O-p-methoxy-
benzylidene-2-deoxy-2-(2,2,2-trichloro-ethoxylcarbonyl-
amino)-1-thio-b-D-glucopyranoside (22). Compound 21
(1.03 g, 1.8 mmol) in pyridine (30.0 mL) was stirred at 0 8C
and benzoyl chloride (1.0 mL, 1.00 g, 7.1 mmol) was added.
After 5 h, pyridine was evaporated in vacuum and the
residue was dissolved in CH2Cl2. The resulting pyridinium
salt was filtered off, and the filtrate was concentrated. The
residue was recrystallized with petroleum ether/EtOAc (1:2)
to give a yellow crystal (1.02 g, 83%). 1H NMR (300 MHz,
CDCl3) d: 8.02 (d, JZ7.2 Hz, 2H, aromatic), 7.54 (t, JZ
7.5 Hz, 1H, aromatic), 7.37–7.46 (m, 4H, aromatic), 7.27
(d, JZ8.7 Hz, 2H, aromatic), 7.09 (d, JZ7.8 Hz, 2H,
aromatic), 6.73 (d, JZ9.0 Hz, 2H, aromatic), 5.90 (d,
JZ9.9 Hz, 1H), 5.66 (t, JZ9.6 Hz, 1H), 5.45 (s, 1H,
p-methyloxybenzylidene-CH), 4.80 (d, JZ10.5 Hz, 1H),
4.58–4.71 (ABq, JZ12.3 Hz, 2H), 4.23 (dd, JZ4.8,
10.2 Hz, 1H), 4.05 (q, JZ10.2 Hz, 1H), 3.80 (q, JZ
9.3 Hz, 2H), 3.72 (s, 3H), 3.60–3.65 (m, 1H), 2.32 (s, 3H,
SPhCH3); 13C NMR (75 MHz, CDCl3) d: 166.7, 160.0,
154.4, 138.4, 133.5, 133.3, 130.2, 130.0, 129.8, 129.3,
129.1, 128.5, 128.4, 127.3, 113.5, 101.2, 95.3, 88.4, 78.6,
74.4, 73.4, 70.7, 68.4, 55.2, 21.2; MALDI-TOF-MS (MC
H)C682. Anal. Calcd for C31H30Cl3NO8S: C, 54.52; H,
4.43; N, 2.05. Found: C, 54.53; H, 4.52; N, 1.92.
1
solid (29.7 mg, 91%). H NMR (300 MHz, CDCl3) d: 7.95
(d, JZ7.2 Hz, 2H, aromatic), 7.53 (t, JZ7.5 Hz, 1H, aro-
matic), 7.33–7.38 (m, 4H, aromatic), 7.08 (d, JZ7.2 Hz,
2H, aromatic), 5.61 (d, JZ9.3 Hz, 1H), 5.34 (t, JZ9.3 Hz,
1H), 4.79 (d, JZ10.5 Hz, 1H), 4.69 (d, JZ12.0 Hz, 1H),
4.53 (d, JZ12.3 Hz, 1H), 3.53–3.96 (m, 4H), 3.49–3.52 (m,
1H), 2.67(br, 2H), 2.31 (s, 3H, SPhCH3); 13C NMR (75 MHz,
CDCl3) d: 167.4, 154.3, 138.4, 133.7, 132.9, 130.0, 129.8,
128.9, 128.5, 95.3, 87.2, 79.4, 74.3, 69.3, 62.3, 55.0, 21.2.
4.1.12. p-Methylphenyl 3-O-benzoyl-6-O-tert-butyldi-
phenylsilyl-2-deoxy-2-(2,2,2-trichloroethoxyl carbonyl-
amino)-1-thio-b-D-glucopyranoside (15). To a solution
of 23 (1.60 g, 2.9 mmol) in DMF (10.0 mL), tert-butyldi-
phenylsilyl chloride (1.5 mL, 1.60 g, 5.7 mmol) and imida-
zole (0.50 g, 7.2 mmol) were added. The mixture was stirred
overnight. After removal of the solvent, the residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ3:1), yielding a yellow solid (1.90 g, 86%).
1H NMR (300 MHz, CDCl3) d: 8.00 (d, J Z 7.2 Hz, 2H,
aromatic) 7.66–7.71 (m, 4H, aromatic), 7.54 (t, JZ7.2 Hz,
1H, aromatic), 7.24–7.42 (m, 10H, aromatic), 7.03 (d, JZ
8.1 Hz, 2H, aromatic), 5.32 (t, JZ9.0 Hz, 2H), 4.73 (d, JZ
10.5 Hz, 1H), 4.71 (d, JZ12.0 Hz, 1H), 4.53 (d, JZ
12.3 Hz, 1H), 3.83–3.97 (m, 5H), 3.51–3.56 (m, 1H), 2.30
(s, 3H, SPhCH3), 1.05 (s, 9H, C(CH3)3); 13C NMR
(75 MHz, CDCl3) d: 167.3, 154.1, 138.2, 135.7, 135.6,
133.6, 133.0, 132.8, 132.7, 130.1, 129.9, 129.7, 129.1,
128.4, 95.3, 87.3, 79.3, 74.4, 70.5, 64.3, 54.8, 26.8, 21.2,
19.2; MALDI-TOF-MS (MCH)C 802.
4.1.10. p-Methylphenyl 3-O-benzoyl-6-O-p-methoxyben-
zyl-2-deoxy-2-(2,2,2-trichloroethoxyl carbonylamino)-1-
thio-b-D-glucopyranoside (14). Compound 22 (0.70 g,
˚
1.0 mmol), NaCNBH3 (0.34 g, 5.2 mmol), and 4 A MS
(1.25 g) were stirred in dry DMF (10.0 mL) at room
temperature for 0.5 h under N2. Then the reaction mixture
was cooled to 0 8C, a solution of trifluoroacetic acid
(0.77 mL, 1.17 g, 10.3 mmol) in dry DMF (7.0 mL) was
added dropwise. The reaction temperature was increased to
room temperature in 1.5 h. After another 11 h of stirring, the
reaction mixture was filtered and the filtrate was diluted
with H2O (100 mL), extracted with EtOAc (3!50 mL),
then dried (Na2SO4). The organic phase was concentrated
for column chromatography on silica gel (petroleum ether/
EtOAcZ2:1). Compound 14 (0.57 g, 80%) was obtained as
4.1.13. (3-Benzyl-3-benzyloxycarbonylamino)propyl
2,3,6-tri-O-benzyl-4-O-[2-O-benzoyl-3-O-(2, 3,4,6-tetra-
O-benzyl-a-D-galactopyranosyl)-4,6-O-benzylidene-b-D-
galactopyranosyl]-b-D-glucopyranoside (4). Building
block 7 (0.16 g, 0.25 mmol), building block 8 (0.10 g,
˚
0.21 mmol), and 4 A MS (0.50 g) were stirred in dry CH2Cl2
(10.0 mL) at 0 8C under N2, which was followed by the
addition of NIS (0.13 g, 0.25 mmol) and TfOH (42 mL,
0.5 M in Et2O, 0.015 mmol). After stirred for 0.5 h, TLC
(petroleum ether/acetoneZ3:2) showed complete consump-
tion of building block 8. Then building block 9 (0.23 g,
0.31 mmol), NIS (0.13 g, 0.25 mmol), and TfOH (42 mL,
0.5 M in Et2O, 0.015 mmol) were added to the reaction
mixture. The reaction mixture was stirred for 3 h and
quenched with triethylamine, then filtered off through
Celite. The filtrate was washed sequentially with satd aq
NaHCO3 and brine, dried (Na2SO4), filtered, and concen-
trated. The residue was purified by column chromatography
on silica gel (petroleum ether/acetoneZ4:1). The product
1
a white solid. H NMR (300 MHz, DMSO-d6) d: 8.03 (d,
JZ9.6 Hz, 1H, aromatic) 7.90 (d, JZ7.2 Hz, 2H, aromatic),
7.63 (t, JZ7.2 Hz, 1H, aromatic), 7.49 (t, JZ7.8 Hz, 2H,
aromatic), 7.36 (d, JZ8.1 Hz, 2H, aromatic), 7.24 (d, JZ
8.4 Hz, 2H, aromatic), 7.07 (d, JZ8.4 Hz, 2H, aromatic),
6.90 (d, JZ8.7 Hz, 2H, aromatic), 5.61 (d, JZ5.4 Hz, 1H),
5.20 (t, JZ9.3 Hz, 1H), 4.91 (d, JZ10.5 Hz, 1H), 4.80 (d,
JZ12.6 Hz, 1H), 4.58 (d, JZ12.9 Hz, 1H), 4.35–4.47 (m,
2H), 3.26–3.70 (m, 8H), 2.26 (s, 3H, SPhCH3); 13C NMR
(75 MHz, DMSO-d6) d: 165.2, 158.7, 154.1, 136.8, 133.2,
131.2, 130.5, 129.8, 129.7, 129.6, 129.4, 129.1, 128.5,
113.6, 96.0, 85.4, 79.4, 77.4, 73.1, 72.0, 69.0, 68.1, 55.0,
54.7, 20.6; MALDI-TOF-MS (MCNH4)C701. Anal. Calcd
1
(175 mg, 55%) was obtained as a yellow solid. H NMR
(500 MHz, DMSO-d6) d: 7.94 (d, JZ7.5 Hz, 2H, aromatic),
7.61 (t, JZ7.5 Hz, 1H, aromatic), 7.10–7.41 (m, 52H,

4320
Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
aromatic), 5.54 (s, 1H, benzylidene-CH),005.34 (dd, JZ8.5,
10.0 Hz, 1H), 5.29 (d, JZ3.0 Hz, 1H, H-1 ), 5.06 (br.s, 3H),
4.82 (d, JZ7.5 Hz, 1H), 4.18–4.72 (m, 17H), 3.93–4.03
(m, 3H), 3.72–3.79 (m, 4H), 3.40–3.50 (m, 6H), 3.16–3.28
(m, 7H), 1.66–1.82 (m, 2H, OCH2CH2CH2N); 13C NMR
(125 MHz, DMSO-d6) d: 164.5, 139.1, 138.6, 138.5, 138.2,
138.1, 136.9, 133.6, 129.4, 129.0, 128.7, 128.4, 128.3,
128.23, 128.17, 128.1, 128.0, 127.8, 127.7, 127.5, 127.4,
127.3, 127.2, 127.1, 127.0, 126.2, 102.0, 100.3, 99.8, 93.1,
82.1, 81.2, 77.7, 77.2, 75.1, 74.4, 74.2, 74.0, 73.6, 73.4,
73.3, 72.4, 72.1, 71.9, 71.1, 70.7, 68.9, 68.2, 68.1, 66.3,
66.2, 49.9, 43.6, 39.0, 29.0; MALDI-TOF-MS (MCNa)C
1630, (MCK)C 1646. Anal. Calcd for C99H101O19N: C,
73.90; H, 6.33; N, 0.87. Found: C, 73.66; H, 6.53; N, 0.56.
aromatic), 7.10–7.38 (m, 39H, aromatic), 6.97 (dd, JZ2.0,
7.5 Hz, 2H, aromatic), 6.72–60.80 (m, 3H, aromatic), 5.64
(dd, JZ8.5, 10.0 Hz, 1H, H-2 ), 5.31 (s, 1H, benzylidene-
CH), 4.96–5.06 (m, 6H), 4.79 (d, JZ11.5 Hz, 1H), 4.72 (d,
JZ8.5 Hz, 1H), 4.50–4.63 (m, 5H), 4.44 (d, JZ12.0 Hz,
1H), 4.21–4.38 (m, 7H), 4.04–4.12 (m, 4H), 3.97 (dd, JZ
3.5, 10 Hz, 1H), 3.83–3.92 (m, 2H), 3.81 (dd, JZ3.5,
10.0 Hz,1H), 3.67–3.72 (m, 3H), 3.51–3.55 (m, 2H), 3.38–
3.41 (m, 2H), 3.27 (dd, JZ7.0, 9.0 Hz, 1H), 3.15–3.18 (m,
1H), 2.98–3.02 (m, 1H), 1.65–1.74 (m, 2H, OCH2CH2CH2-
N); 13C NMR (125 MHz, CDCl3) d: 167.7, 164.7, 156.3,
138.7, 138.68, 138.6, 138.5, 138.3, 138.1, 137.8, 136.7,
133.6, 133.1, 131.6, 130.9, 129.8, 128.7, 128.44, 128.4,
128.3, 128.2, 128.14, 128.1, 128.0, 127.9, 127.8, 127.78,
127.7, 127.6, 127.5, 127.4, 127.3, 127.2, 126.8, 126.3,
123.2, 101.1, 100.8, 98.2, 95.8, 78.5, 78.2, 75.8, 75.3, 75.1,
74.9, 74.7, 74.6, 73.2, 73.2, 73.1, 72.3, 72.2, 71.3, 69.9,
68.9, 68.6, 67.8, 66.6, 66.4, 66.3, 65.5, 58.4, 55.6, 37.7,
29.1; TOF-MS (MCNH4)C 1574. Anal. Calcd for
C93H92O20N2: C, 71.71; H, 5.95; N, 1.80. Found: C,
71.49; H, 5.89; N, 1.55.
4.1.14. 3-Aminopropyl 4-O-[3-O-(a-D-galactopyranosyl)-
b-D-galactopyranosyl]-b-D-glucopyranoside (1). Com-
pound 4 (60.0 mg, 0.037 mmol) was dissolved in methanol
(5.0 mL), and to this NaOMe (30% in MeOH, 10 mL) was
added. The mixture was stirred for 6 h and then neutralized
with cation exchange resin (HC). The resin was filtered off
and the filtrate was evaporated in vacuum. The residue was
purified by silica gel column chromatography (petroleum
ether/acetoneZ4:1). A mixture of the purified residue, 10%
Pd–C (15.0 mg) in HOAc (4 mL), THF (2 mL), H2O (1 mL)
was stirred under H2 atmosphere for 24 h. The catalyst was
then removed by filtration and the filtrate was concentrated.
The residue was subjected to a C-18 reverse phase column
chromatography (H2O) to give 1 (14.6 mg, 70%) as a white
solid after lyophilization. 1H NMR (500 MHz, D2O) d: 5.13
(d, JZ3.5 Hz, 1H, H-100), 4.51 (d, JZ8.0 Hz, 1H), 4.50 (d,
JZ8.0 Hz, 1H), 4.16–4.20 (m, 2H), 3.90–4.10 (m, 4H),
3.69–3.89 (m, 8H), 3.55–3.69 (m, 4H), 3.15 (t, JZ7.0 Hz,
2H, OCH2CH2CH2N), 1.98–2.05 (m, 2H, OCH2CH2CH2N);
13C NMR (125 MHz, D2O) d: 182.1, 103.6, 102.8,
96.2 (C-100), 79.4, 77.9, 75.8, 75.5, 75.2, 73.5, 71.6,
70.3, 70.0, 69.9, 68.9, 68.6, 65.5, 61.7, 61.6, 60.8, 38.3
(OCH2CH2CH2N), 27.4 (OCH2CH2CH2N), 23.9; HRMS
(MCNa) calcd for C21H39O16NNa 584.2167, found
584.2168.
4.1.16. 3-Aminopropyl 4-O-[3-O-(a-D-galactopyranosyl)-
b-D-galactopyranosyl]-2-acetamido-2-deoxy-b-D-gluco-
pyranoside (2). Compound 5 (44.0 mg, 0.028 mmol) was
dissolved in EtOH (3.0 mL) and treated with NH2NH2$H2O
(1.0 mL). The mixture was heated under reflux for 24 h, it
was then concentrated under reduced pressure and the
residue was co-evaporated with toluene (3!5 mL). The
crude product was dissolved in pyridine (3.0 mL) and acetic
anhydride (1.0 mL). After stirring for 8 h, the solvent was
removed in vacuum. The residue was dissolved in methanol
(3.0 mL), and NaOMe (30% in MeOH, 10 mL) was added.
The mixture was stirred for 6 h and then neutralized with
cation exchange resin (HC). The resin was filtered off and
the filtrate was evaporated in vacuum. The residue was
purified by silica gel column chromatography (petroleum
ether/acetoneZ4:1). A mixture of the purified residue, 10%
Pd–C (15.0 mg) in HOAc (4.0 mL), THF (2.0 mL), H2O
(1.0 mL) was stirred under H2 atmosphere for 24 h. The
catalyst was then removed by filtration and the filtrate was
concentrated. The residue was subjected to a C-18 reverse
phase column chromatography (H2O) to give 2 (12.0 mg,
70%) as a white solid after lyophilization. 1H NMR
(500 MHz, D2O) d: 5.14 (d, JZ3.0 Hz, 1H, H-100), 4.54
(d, JZ8.0 Hz, 1H), 4.52 (d, JZ8.0 Hz, 1H), 4.15–4.21 (m,
2H), 3.97–4.40 (m, 3H), 3.94 (dd, JZ3.0, 10 Hz, 1H), 3.63–
3.88 (m, 12H), 3.58–3.63 (m, 2H), 3.08 (t, JZ7.0 Hz, 2H,
OCH2CH2CH2N), 2.04 (s, 3H, CH3CON), 1.92–1.97 (m,
2H, OCH2CH2CH2N); 13C NMR (125 MHz, D2O) d: 175.4
(CH3CON), 103.6, 101.9, 96.2 (C-100), 79.4, 77.9, 75.8,
75.4, 73.0, 71.6, 70.3, 70.0, 69.9, 68.9, 68.7, 65.5, 61.7,
61.6, 60.8, 55.8, 38.6 (OCH2CH2CH2N), 27.4 (OCH2CH2-
CH2N), 24.0, 22.9; HRMS (MCNa) calcd for
C23H42O16N2Na 625.2432, found 625.2439.
4.1.15. (3-Benzyloxycarbonylamino)propyl 3,6-di-O-
benzyl-4-O-[2-O-benzoyl-3-O-(2,3,4,6-tetra-O-benzyl-a-
D-galactopyranosyl)-4,6-O-benzylidene-b-D-galactopyr-
anosyl]-2-deoxy-2-phthalimido-b-D-glucopyranoside (5).
Building block 7 (0.82 g, 1.25 mmol), building block 8
˚
(0.50 g, 1.05 mmol), and 4 A MS (1.00 g) were stirred in dry
CH2Cl2 (30.0 mL) at 0 8C under N2, which was followed by
the addition of NIS (0.66 g, 1.25 mmol) and TfOH
(0.21 mL, 0.5 M in Et2O, 0.105 mmol). After stirred for
0.5 h, TLC (petroleum ether/acetoneZ3:2) showed com-
plete consumption of building block 8. Then building block
10 (1.20 g, 1.58 mmol), NIS (0.66 g, 1.25 mmol), and TfOH
(0.21 mL, 0.5 M in Et2O, 0.105 mmol) were added to the
reaction mixture. The reaction mixture was stirred for 3 h
and quenched with triethylamine, then filtered off through
Celite. The filtrate was washed sequentially with satd aq
NaHCO3 and brine, dried (Na2SO4), filtered, and concen-
trated. The residue was purified by column chromatography
on silica gel (petroleum ether/acetoneZ4:1). The product
4.1.17. (3-Benzyl-3-benzyloxycarbonylamino)propyl
2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-3-O-{3,6-di-
O-benzyl-2-deoxy-2-phthalimido-4-O-[2-O-benzoyl-3-O-
(2,3,4,6-tetra-O-benzyl-a-D-galactopyranosyl)-4,6-O-
benzylidene-b-D-galactopyranosyl]-b-D-glucopyrano-
syl}-b-D-galactopyranosyl)-b-D-glucopyranoside (6).
Building block 11 (30.0 mg, 0.030 mmol), building block
1
(814.0 mg, 55%) was obtained as a yellow solid. H NMR
(500 MHz, CDCl3) d: 8.00 (d, JZ7.5 Hz, 2H, aromatic),
7.60–7.65 (m, 2H, aromatic), 7.51 (t, JZ7.5 Hz, 1H,

Y. Wang et al. / Tetrahedron 61 (2005) 4313–4321
4321
1215 (21.5 mg, 0.036 mmol), BSP (2.9 mg, 0.015 mmol),
T.; Ye, Y.; Koren, E.; Cummings, R. D.; Cooper, D. K.
Transplantation 1996, 62(9), 1324–1331. (b) Simon, P. M.;
Neethling, F. A.; Taniguchi, S.; Goode, P. L.; Zopf, D.;
Hancock, W. W.; Cooper, D. K. Transplantation 1998, 65(3),
346–353.
˚
and 4 A MS (0.20 g) were stirred in dry CH2Cl2 (2.0 mL) at
room temperature for 0.5 h under N2. The mixture was
cooled to K70 8C, followed by the addition of Tf2O
(3.1 mL, 5.1 mg, 0.018 mmol), then warmed gradually to
room temperature. After 3 h, the donor was consumed and
the reaction temperature was cooled to K70 8C again, to
add a solution of building block 1315 (45.0 mg, 0.039 mmol)
and BSP (2.9 mg,, 0.015 mmol) in dry CH2Cl2 (2.0 mL).
Subsequently Tf2O (3.1 mL, 5.1 mg, 0.018 mmol) was
added to the reaction mixture which was then warmed
gradually to room temperature. After 3 h, the reaction was
quenched with triethylamine (2.0 mL) and diluted with
CH2Cl2 (10.0 mL). The reaction mixture was filtered and
washed sequentially with satd aq NaHCO3 and brine, dried
(Na2SO4), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (petroleum
ether/EtOAcZ3:1). The product (31.4 mg, 42%) was
obtained as a yellow syrup. Saccharide 6 was spectro-
metrically identical to an authentic sample prepared
previously.15
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Acknowledgements
This work was financially supported by the National Natural
Science Foundation of China and Peking University. Q.Y.
and J.W. are on study leave from Department of Basic
Science, Huazhong Agricultural University, Wuhan, China.
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