Synthesis of a divalent glycoside of an α-galactosyl disaccharide epitope involved in the hyperacute rejection of xenotransplantation

Article abstract of DOI:10.1016/S0008-6215(01)00194-X

3,6-Dioxaoct-1,8-diyl di-(3-O-α-D-galactopyranosyl-β-D-galactopyranoside) was synthesized for use in research on hyperacute rejection of xenotransplantation. The trichloroacetate method was successfully applied to form stereoselectively the α-D-galactosyl

Full text of DOI:10.1016/S0008-6215(01)00194-X

www.elsevier.com/locate/carres
Carbohydrate Research 334 (2001) 289–294
Synthesis of a divalent glycoside of an a-galactosyl
disaccharide epitope involved in the hyperacute rejection
of xenotransplantationꢀ
Yi-Pin Lu, Hui Li, Meng-Shen Cai, Zhong-Jun Li*
Department of Bioorganic Chemistry, School of Pharmaceutical Sciences,
National Research Laboratory of Natural and Biomimetic Drugs, Peking Uni6ersity, Beijing 100083, China
Received 27 November 2000; accepted 4 July 2001
Abstract
3,6-Dioxaoct-1,8-diyl di-(3-O-a-
hyperacute rejection of xenotransplantation. The trichloroacetate method was successfully applied to form stereo-
-galactosyl linkage under mild reaction conditions and a simple procedure. The divalent O-gly-
D
-galactopyranosyl-b-D-galactopyranoside) was synthesized for use in research on
selectively the a-
D
coside was formed from the corresponding trichloroacetimidate in one step with reasonable yield. © 2001 Elsevier
Science Ltd. All rights reserved.
Keywords: Divalent glycoside; Hyperacute rejection; Synthesis; Trichloroacetate method
1. Introduction
to xenotransplantation. HAR has been found
to be triggered by the binding of xenoreactive
natural antibodies in humans to the endothe-
lial lining of the blood vessels within the graft.
These natural occurring antibodies, termed
anti-Gal, specifically recognize a-Gal-(1“3)-
Gal, which is presented on the surface of the
endothelial cells of most mammalian species
except for humans, apes, and Old World
monkeys.5,6
One strategy to prevent anti-Gal binding to
the endothial cells is the use of synthetic anti-
gens either as immunoabsorption agents to
remove anti-Gal from the recipient’s circula-
tion or as soluble substances to inhibit the
binding. However, it is known that most car-
bohydrate–protein interactions are rather
weak.7 The multivalent effect has been recog-
nized as an effective way to increase binding
interactions between carbohydrates and
proteins.8 Accordingly, we designed and syn-
The shortage of donor organs and tissues is
the most urgent problem in transplantation
today. This has increased the interest in the
possible use of xenogeneic organs for trans-
plantation in humans.1,2 Considered from the
aspects of availability, a suitable size of the
organ, genetical manipulation, ethics and vi-
rology, the pig is the most favored species at
present.3,4 However, if a pig organ is trans-
planted into an untreated human, it would
almost certainly be destroyed over a period of
minutes to hours by hyperacute rejection
(HAR), an important immunological barrier
ꢀ Studies on Carbohydrates. Part XLVI.
* Corresponding author. Tel.: +86-10-62091504; fax: +
86-10-62367134.
E-mail address: zjli@mail.bjmu.edu.cn (Z.-J. Li).
0008-6215/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00194-X

290
Y.-P. Lu et al. / Carbohydrate Research 334 (2001) 289–294
from p-methoxyphenyl 2,3,4,6-tetra-O-acetyl-
b- -galactopyranoside (2) by the ‘dibutyltin
D
oxide alkylation’ procedure9 in four steps and
67% overall yield. Compound 210 was deacety-
lated and then regioselectively benzylated via
a dibutyl tin oxide-mediated reaction with
benzyl bromide as the reagent and Bu4NI as
the catalyst to afford compound 4 as a pale
yellow solid. TLC indicated 4 to be contami-
nated with 10–15% of unknown compound,
which was difficult to separate by chromatog-
raphy. Conventional direct acetylation of
crude 4 afforded the fully protected com-
pound 5, which could be readily crystallized
pure from ice-water. The unknown contami-
nant was readily separated in this step as it
still stayed in the aqueous layer. Catalytic
hydrogenolysis under standard conditions
Scheme 1. (a) NaOMe, MeOH; (b) (1) Bu2SnO, toluene,
reflux, 17 h; (2) BnBr, Bu4NI, toluene, reflux, 2 h; (c) Ac2O,
Py, rt, 18 h; (d) H2, Pd–C (10% Pd), MeOH, rt, 10 h; (e)
CCl3COONa, (CCl3CO)2O, CH2Cl2, reflux, 1.5 h.
thesized the novel divalent glycoside 1, which
could be useful in the research of hyperacute
rejection in xenotransplantation.
gave the nucleophile 6, isolated as an amor-
phous white solid.
Trichloroacetoxy, a novel glycosyl anomeric
leaving group, was reported by our laboratory
in successful preparations of many glycosides
and oligosaccharides under mild reaction con-
ditions and simple procedures.11–17 Here we
used this method to prepare disaccharide 9.
2. Results and discussion
The synthetic route for dimer 1 is outlined
in Schemes 1 and 2. A fully protected glycotet-
raose 13 is designed as a direct precursor for
compound 1.
The galactopyranosyl acceptor 6, unsubsti-
tuted at O-3, was conveniently synthesized
2,3,4,6 - Tetra - O - benzyl -
D
- galactopyranose
(7)19 was converted into trichloroacetyl
,
Scheme 2. (a) Me3SiOTf, CH2Cl2–Et2O, 4 A MS, −20 °C, 30 min; (b) CAN, CH3COCH3–H2O, rt, 5 h; (c) CCl3CN, DBU, 0 °C,
4 h; (d) Me3SiOTf, CH2Cl2, 4 A MS, 0 °C, 20 min; (e) NaOMe, MeOH–CH2Cl2 (1:1), rt, 24 h; (f) Pd–C, H2, MeOH, 20 h.
,

Y.-P. Lu et al. / Carbohydrate Research 334 (2001) 289–294
291
of the donor occurred can lead to glycosyla-
tion. Possibly, the catalyst had already been
decomposed by the triethylene glycol before
the addition of the donor.
Deacetylation of 13 followed by debenzyla-
tion furnished the target divalent glycoside 1
in 94% yield.
2,3,4,6-tetra-O-benzyl- -galactopyranose (8),
D
an activated glycosyl donor, by treatment with
trichloroacetic anhydride in the presence of
sodium trichloroacetate.16 Compound 8 is sta-
ble and can be stored at room temperature for
a long time. The yield is nearly quantitative
and the product pure enough for use in the
next step without further purification. The
trichloroacetate 8 reacted with 6 at room tem-
perature in 1:3 CH2Cl2–Et2O with Me3SiOTf
as promoter to give the a-disaccharide 9 in
good yield (two crops, 69%) with high
stereoselectivity (a:b=11:1). The configura-
tion of the disaccharide was indicated by the
characteristic coupling constant (J1%,2% 3.3 Hz)
Immunological inhibition experiments with
this novel dimer are now in progress.
3. Experimental
General methods.—Solvents were purified
conventionally. Optical rotations were mea-
sured using an optical activity AA-10R type
polarimeter. Melting points were uncorrected.
NMR spectra were recorded with Bruker
ARX-400 or Varian VXR-300 spectrometers.
Mass spectra were recorded with a ZAB-HS
spectrometer (FAB) and a LDI-1700 spec-
trometer (MALDI-TOF). Column chromatog-
raphy was performed on silica gel H (10–40
mm) (Hai Yang Chemical Factory, Qingdao,
Shandong, China). The purity of the product
was determined by TLC on silica gel GF254
(Hai Yang Chemical Factory, Qingdao, Shan-
dong, China). Elemental analyses were per-
formed on Perkin–Elmer 240C instrument.
13
and confirmed in C NMR by the C-1% chem-
ical shift (l 94.9 ppm). When the condensa-
tion was carried out in dichloromethane at
0 °C, the ratio of a:b is only 16:5.
Removal of the p-methoxyphenyl group in
9 using ammonium cerium(IV) nitrate (CAN)
afforded 10 as an anomeric mixture (67%,
a:b=4:1), which on treatment with DBU and
trichloroacetonitrile in dichloromethane gave
the a-imidate 11 in 81% yield. Condensation
of 11 with triethylene glycol (12) in dry
dichloromethane, using 0.25 equiv (based on
the donor) of Me3SiOTf as promotor, gave
the desired dimer 13 (57%) in one step. The
symmetric b configuration was confirmed by
1H NMR (J1,2 8.0 Hz), 13C NMR (l 101.6
ppm), and TOF-MS ([M+Na]+: 1793.4;
[M+K]+: 1809.8).
p-Methoxyphenyl 3-O-benzyl-i-
pyranoside (4).—To a solution of p-methoxy-
phenyl 2,3,4,6 - tetra - O - acetyl - b - - galacto-
D
-galacto-
D
pyranoside (2)10 (9.0 g, 20 mmol) in dry
MeOH (100 ml) was added NaOMe (0.15 g,
2.8 mmol). After 2 h, the mixture was neutral-
ized with H+ cation-exchange resin, filtered,
and concentrated to afford 3. The crude
product 3 (5.0 g, 17 mmol) was dissolved in
dry toluene, and dibutyltin oxide (4.4 g, 17
mmol) was added. The mixture was refluxed
with azeotropic removal of the generated wa-
ter for 17 h. Tetrabutylammonium iodide (6.5
g, 17 mmol) and BnBr (3.1 mL, 26 mmol)
were then added, and the mixture was stirred
at reflux temperature for additional 2 h. Ex-
amination by TLC (4:1 CH2Cl2–CH3COCH3)
showed only traces of 3 remaining and the
predominant presence of 4 (Rf 0.42). The
dark-orange solution was concentrated to dry-
ness and the resulting residue was chro-
matographed (25:1 CH2Cl2–MeOH) to give 4
We also examined various other reaction
conditions. When the condensation was pro-
moted by 0.12 equiv Me3SiOTf, most of 11
was converted into
a
self-condensation
product. Attempted glycosylations with boron
trifluoride etherate or silver trifluoromethane-
sulfonate as promotor were unsuccessful and
most of the donor was converted into the
hemiacetal 10. The result showed that the
condensation required a strong catalyst. In
order to decrease the decomposition of the
donor, we also tried the ‘inverse procedure’
(addition of the donor to an acceptor–catalyst
solution).18 Unfortunately, no obvious reac-
tion occurred after 45 min and prolongation
of the reaction time only led to the decompo-
sition of the donor. Addition of a second
portion of the catalyst before decomposition

292
Y.-P. Lu et al. / Carbohydrate Research 334 (2001) 289–294
with hydrogen. After 10 h TLC (1:1 petroleum
ether–EtOAc) indicated the reaction to be
complete and the product was isolated con-
ventionally and collected as a white solid, mp
as an amorphous solid (5.7 g, 87%), contami-
nated by 10–15% of a co-eluting compound.
A portion of 4 was recrystallized from
MeOH–Et2O to give a pure sample: mp 155–
156 °C, [h]2D6 −8.0° (c 1.0, CH3OH); 1H NMR
(Me2SO-d6): l 7.46–7.27 (m, 5 H, PhCH2),
6.99 (d, 2 H, J 9.3 Hz, C6H4OCH3), 6.85 (d, 2
H, J 9.3 Hz, C6H4OCH3), 5.35 (d, 1 H, J1,2 5.1
Hz, H-1), 4.75–4.65 (m, 5 H, PhCH2, 3×
OH), 4.58 (d, 1 H, J 12 Hz, PhCH2), 3.99 (dd,
1 H, J 3.3, J 4.8 Hz, H-4), 3.75 (m, 1 H, H-2),
3.70 (s, 3 H, OCH3), 3.60–3.33 (m, 4 H, H-5,
H-6a, H-6b, H-3); 13C NMR (Me2SO-d6): l
154.3, 151.5, 139.0, 128.0, 127.5, 127.1, 117.8
and 114.4 (Ph), 102.1 (C-1), 81.2 (C-3), 75.2
(C-5), 70.2 (PhCH2), 69.4 (C-2), 64.6 (C-4),
60.3 (C-6), 55.3 (OCH3); FAB-MS: [M+K]+
414.8. Anal. Calcd for C20H24O7: C, 63.83; H,
6.38. Found: C, 64.08; H, 6.46.
1
130–132 °C, [h]2D6 +8.0° (c 1.0, CHCl3); H
NMR (CDCl3): l 6.96 (d, 2 H, J 8.7 Hz,
C6H4OCH3), 6.82 (d, 2 H, J 8.7 Hz,
C6H4OCH3), 5.38 (d, 1 H, J3,4 3.3 Hz, H-4),
5.22 (dd, 1 H, J1,2 7.5, J2,3 9.9 Hz, H-2), 4.88
(d, 1 H, H-1), 4.19 (d, 2 H, H-6a, H-6b),
3.97–3.89 (m, 2 H, H-5, H-3), 3.78 (s, 3 H,
OCH3), 2.20, 2.16 and 2.06 (3s, 3×3 H, 3×
CH3CO); 13C NMR (CDCl3): l 171.1, 170.8,
170.4 (3 C, CH3CO), 155.8, 151.2, 118.7 (2 C)
and 114.6 (2 C) (Ph), 100.6 (C-1), 72.7 (C-2),
71.5, 71.3 (C-5, C-3), 69.6 (C-4), 61.9 (C-6),
55.7 (OCH3), 20.9, 20.7 and 20.6 (3 C, 3×
CH3CO); FAB-MS: [M+K]+ 450.8. Anal.
Calcd for C19H24O10: C, 55.34; H, 5.82.
Found: C, 55.09; H, 5.79.
p-Methoxyphenyl
2,4,6-tri-O-acetyl-3-O-
benzyl-i- -galactopyranoside (5).—A solu-
D
p-Methoxyphenyl
(2,3,4,6-tetra-O-benzyl-h-
i- -galactopyranoside (9).—To a solution of
2,4,6-tri-O-acetyl-3-O-
tion of crude 4 (4.0 g) in pyridine (60 mL) was
treated with Ac2O (30 mL) at 0 °C and the
mixture was stirred for 18 h at rt. The mixture
was then poured into ice-water and stirred,
whereupon the product crystallized. Recrystal-
lization from EtOH gave pure 5 (6.0 g, 69% in
two crops) as white needles: mp 91–92 °C,
[h]2D6 +55.4° (c 1.0, CHCl3); 1H NMR
(CDCl3): l 7.34–7.25 (m, 5 H, PhCH2), 6.93
(d, 2 H, J 9.3 Hz, C6H4OCH3), 6.79 (d, 2 H, J
9.3 Hz, C6H4OCH3), 5.55 (d, 1 H, J3,4 3.3 Hz,
H-4), 5.37 (dd, 1 H, J1,2 7.5, J2,3 9.9 Hz, H-2),
4.81 (d, 1 H, J1,2 7.5 Hz, H-1), 4.72 (d, 1 H, J
12.0 Hz, PhCH2), 4.43 (d, 1 H, J 12.6 Hz,
PhCH2), 4.21 (d, 2 H, H-6a, H-6b), 3.90 (m, 1
H, H-5), 3.76 (s, 3 H, OCH3), 3.61 (dd, 1 H,
J3,4 3.3 Hz, H-3), 2.18, 2.08 and 2.05 (3s, 9 H,
D
-galactopyranosyl)-
D
719 (1.00 g, 1.85 mmol) in dry CH2Cl2 (20 mL)
was added Cl3CCO2Na (0.35 g, 1.89 mmol)
and trichloroacetic anhydride (0.50 mL, 2.74
mmol). The mixture was refluxed with stirring
for 1.5 h, and then 15 mL CH2Cl2 was added
to the cooled flask. The mixture was washed
with aq NaHCO3, ice-water, dried (Na2SO4)
and concentrated to give 8 as a syrup (1.36 g,
99%).
A mixture of 8 (1.24 g, 1.81 mmol), 6 (0.90
,
g, 2.18 mmol) and powered 4 A molecular
sieves in 80 mL of dry 1:3 CH2Cl2–Et2O was
stirred at rt. After 30 min, 0.76 mL Me3SiOTf
was added dropwise and the mixture was
stirred at rt for 30 min. The mixture was
neutralized with Et3N, diluted with CH2Cl2,
and filtered over Celite. The filtrate was
washed with satd aq NaHCO3, water, then
dried (Na2SO4) and concentrated. The residue
was chromatographed 20:1 toluene–acetone
to afford 9 (1.19 g, two steps 69%) as a foam,
[h]2D6 +74.2° (c 1.2, CHCl3); 1H NMR
(CDCl3): l 7.39–7.24 (m, 20 H, PhCH2), 6.92
(d, 2 H, J 9.3 Hz, C6H4OCH3), 6.80 (d, 2 H, J
9.3 Hz, C6H4OCH3), 5.49 (d, 1 H, J3,4 3.3 Hz,
H-4), 5.43 (dd, 1 H, J1,2 8.1, J2,3 10.2 Hz, H-2),
5.10 (d, 1 H, J1%,2% 3.3 Hz, H-1%), 4.95–4.36 (m,
13
3×CH3CO); C NMR (CDCl3): l 170.4 and
169.2 (3 C, 3×CH3CO), 155.7, 151.3, 137.4,
128.4 (2 C), 127.9, 127.8, 118.6 (2 C), and
114.5 (2 C) (Ph), 100.9 (C-1), 71.4, 71.2, and
70.4 (C-3, C-2, C-5), 65.8 (C-4), 62.0 (C-6),
55.7 (OCH3), 20.8 (2 C) and 20.6 (3×
CH3CO); FAB-MS: [M+K]+ 541.6. Anal.
Calcd for C26H30O10: C, 62.15; H, 5.98.
Found: C, 61.95; H, 6.02.
p-Methoxyphenyl
2,4,6-tri-O-acetyl-i- -
D
galactopyranoside (6).—A solution of 5 (3.1 g,
6.2 mmol) in MeOH was treated with a cata-
lytic amount of Pd–C (10% Pd) and reduced

Y.-P. Lu et al. / Carbohydrate Research 334 (2001) 289–294
293
the residue was chromatographed (6:1
petroleum ether (60–90 °C)–EtOAc+1%
Et3N) to give 11 (665 mg, 81%) as a colorless
9 H, 4×PhCH2, H-1), 4.13 (t, 2 H, H-6a,
H-6b), 4.02 (dd, 1 H, J1%,2% 3.3, J2%,3% 11.1 Hz,
H-2%), 3.92–3.90 (m, 2 H, H-5, H-5%), 3.86–
3.80 (m, 3 H, H-3, H-3%, H-4%), 3.78 (s, 3 H,
OCH3), 3.51 (t, 2 H, H-6%a, H-6%b), 2.06, 1.97
and 1.84 (3s, 3×H, 3×CH3CO); 13C NMR
(CDCl3): l 170.3 and 169.0 (3 C, 3×CH3CO),
155.7, 151.4, 138.8, 138.7, 138.2, 128.4, 128.2,
128.1, 128.0, 127.7, 127.6, 127.5, 118.6, 114.6
(Ph), 101.1 (C-1), 94.9 (C-1%), 78.6 (C-4%), 75.9
(C-2%), 75.5 (C-3%), 74.8, 73.5 and 73.3 (4 C,
4×PhCH2), 72.8 (C-3), 71.4 (C-5), 70.2 and
70.1 (C-2, C-5%), 68.9 (C-6%), 65.1 (C-4), 62.0
(C-6), 55.7 (OCH3), 20.8, 20.7 and 20.4 (3×
CH3CO); TOF-MS: [M+Na]+ 956.3, [M+
K]+ 972.0. Anal. Calcd for C53H58O15: C,
68.09; H, 6.21. Found: C, 68.23; H, 6.39.
2,4,6-Tri-O-acetyl-3-O-(2,3,4,6-tetra-O-
1
foam; H NMR (CDCl3): l 8.61 (s, 1 H, NH),
7.38–7.20 (m, 20 H, 4×PhCH2), 6.60 (d, 1 H,
J1,2 3.3 Hz, H-1), 5.62 (d, 1 H, J3,4 2.4 Hz,
H-4), 5.30 (dd, 1 H, J2,3 10.5 Hz, H-2), 5.15 (d,
1 H, J1%,2%% 3.0 Hz, H-1%), 4.93–4.49 (m, 6 H,
3×PhCH2), 4.43–4.30 and 4.06–3.93 (2m,
2×4 H, PhCH2, H-4%, H-3%, H-6%, H-3, H-5,
H-6), 4.15 (dd, 1 H, J 6.0, J 11.4 Hz, H-6),
3.85 (dd, 1 H, J 2.7, J 10.2 Hz, H-2%), 3.58 (t,
1 H, J 8.4 Hz, H-5%), 3.40 (dd, 1 H, J1%,2% 5.4,
J2%,3% 8.7 Hz, H-2%), 3.58 (t, 1 H, J 6.0 Hz,
H-5%), 3.40 (dd, 1 H, J 5.4, J 8.7 Hz, H-6%),
2.03, 1.90 and 1.86 (3s, 3×3 H, 3×CH3CO);
13C NMR (CDCl3): l 170.1, 169.9, 163.3 and
160.9 (4 C, 3×CH3CO, HNCCCl3), 138.7,
138.6, 137.9, 128.3, 128.1, 128.0, 127.7, 127.5,
127.4 (24 C, Ph), 94.4 (C-1%), 93.8 and 91.0
(C-1, CCl3), 78.5 (C-4%), 75.9 (C-2%), 75.0, 74.8,
73.6, 73.4, 73.0 (5 C, C-3%, 4× PhCH2), 69.7,
69.5, 68.6, 68.3 and 68.1 (C-5, C-2, C-5%, C-6%,
C-3), 65.7 (C-4), 61.8 (C-6), 20.6, 20.4, and
20.3 (3 C, 3×CH3CO).
benzyl-h-
D
-galactopyranosyl)- -galactopyra-
D
nose (10).—Compound 9 (1.34 g, 1.41 mmol)
was dissolved in acetone (70 mL) and water
(23 mL). The mixture was cooled (ice-water
bath) and a solution of ceric ammonium ni-
trate (CAN, 4.58 g, 8.35 mmol) in 3:1 ace-
tone–water was added. After stirring at rt for
5 h, the mixture was concentrated to 40 mL,
diluted with EtOAc (150 mL), washed with
water. The aqueous layer was extracted twice
with EtOAc. The organic extracts were
washed with aq satd NaCl solution, dried
(Na2SO4), filtered, and concentrated. Column
chromatography of the residue (1.8:1
petroleum ether (60–90 °C)–EtOAc) afforded
10 (0.78 g, 67%, a:b=4:1) as a foam, [h]D26
3,6-Dioxaoct-1,8-diyl-di-[2,4,6-tri-O-acetyl-
3 - O - (2,3,4,6 - tetra - O - benzyl - h -
D
- galacto-
pyranosyl)-i- -galactopyranoside] (13).—A
D
mixture of 11 (300 mg, 0.308 mmol), tri-
ethylene glycol (12, 21 mg, 0.140 mmol) and
,
powered 4 A molecular sieves in 10 mL of dry
CH2Cl2 was stirred at rt for 45 min. Then the
mixture was cooled to 0 °C in an ice-water
bath and 0.03 M Me3SiOTf (2.37 mL) was
added dropwise. The reaction was complete
after 20 min, as indicated by TLC. After
addition of solid NaHCO3 and filtration, the
solution was concentrated and the residue was
chromatographed (1:1 petroleum ether (60–
90 °C)–EtOAc) to give 13 (141 mg, 57%) as a
13
+93.7° (c 1.7, CHCl3); C NMR (CDCl3): l
170.5 and 170.2 (3 C, 3×CH3CO), 138.7,
138.6, 138.1, 128.3, 128.1, 128.0, 127.6, 127.5
(Ph), 96.2 (C-1b), 94.6 (C-1%), 90.6 (C-1a), 20.8
and 20.4 (3 C, 3×CH3CO); TOF-MS: [M+
Na]+ 851.0, [M+K]+ 866.7.
1
3-O-(2,3,4,6-Tetra-O-benzyl-h-
D
-galactopy-
foam, [h]2D6 +68.4° (c 1.2, CHCl3); H NMR
ranosyl)-2,4,6-tri-O-acetyl-h- -galactopyra-
D
(CDCl3): l 7.37–7.24 (m, 20 H, Ph), 5.45 (d, 1
H, J3,4 3.0 Hz, H-4), 5.18 (dd, 1 H, J1,2 8.0, J2,3
10.1 Hz, H-2), 5.08 (d, 1 H, J1%,2% 3.4 Hz, H-1%),
4.93–4.38 (m, 9 H, 4×PhCH2, H-1), 4.08 (d,
2 H, J 6.5 Hz, H-6a, H-6b), 3.99 (dd, J1%%,2% 3.4,
J2%,3% 11.2 Hz, H-2%), 3.94–3.90 (m, 2 H, H-5,
OCH2CHOCH2), 3.87–3.80 (m, 3 H, H-3,
nosyl trichloroacetimidate (11).—To a solution
of 10 (700 mg, 0.845 mmol) and trichloroace-
tonitrile (1.96 mL, 19.4 mmol) in dry CH2Cl2
(35 mL) was added DBU (0.035 mL, 0.23
mmol) at 0 °C. The mixture was stirred in an
ice-water bath. After 4 h, TLC (3:1 petroleum
ether–EtOAc) indicated the reaction to be
complete. The mixture was concentrated and
H-3%,
H-4%),
3.69–3.59
(m,
6
H,
OCH2CHOCH2, H-5%), 3.52–3.51 (d, 2 H, H-

294
Y.-P. Lu et al. / Carbohydrate Research 334 (2001) 289–294
6%a, H-6%b), 2.06, 1.95 and 1.81 (3s, 3×3 H,
3×CH3CO); 13C NMR (CDCl3): l 170.4,
170.3 and 169.2 (3×CH3CO), 138.8, 138.7,
138.1, 128.4, 128.3, 128.2, 128.1, 128.0, 127.7,
127.6, 127.5 and 127.4 (Ph), 101.6 (C-1), 94.7
(C-1%), 78.5 (C-4%), 75.8 (C-2%), 75.4 (C-3%), 74.8,
73.6 (2 C) and 73.3 (4×PhCH2), 72.7 (C-3),
71.1 (C-5), 70.8, 70.2 and 68.9 (OCH2CH2-
OCH2), 70.1 (C-2), 69.9 (C-5%), 68.8 (C-6%), 65.2
(C-4), 61.9 (C-6), 20.8, 20.7, and 20.5 (3×
CH3CO); TOF-MS: [M+Na]+ 1793.4, [M+
K]+ 1809.8. Anal. Calcd for C98H114O30: C,
66.44; H, 6.44. Found: C, 66.16; H, 6.50.
(NSFC) and a grant from the Ministry of
Science and Technology of the PR China.
References
1. Auchincloss, Jr, H. Transplantation 1998, 46, 1–20.
2. Platt, J. L.; Vercellotti, G. M.; Dalmasso, A. P.; Matas,
A. J.; Bolman, R. M.; Najarian, J. S.; Bach, F. H.
Immunol. Today 1990, 11, 450–456.
3. Ye, Y.; Niekrasz, M.; Kosanke, S.; Welsh, R.; Jordan, H.
E.; Fox, J. C.; Edwards, W. C.; Maxwell, C.; Cooper, D.
K. C. Transplantation 1994, 57, 694–703.
4. Hammer, C.; Linke, R.; Wanger, F.; Diefenbeck, M. Int.
Arch. Allergy Immunol. 1998, 116, 5–21.
5. Good, A. H.; Cooper, D. K.; Malcolm, A. J.; Ippolito,
R. M.; Koren, E.; Neethling, F. A.; Ye, Y.; Zuhdi, N.;
Lamontagne, L. R. Transpl. Proc. 1992, 24, 559–562.
6. Rother, R. P.; Squinto, S. P. Cell 1996, 86, 185–188.
7. Toone, E. J. Curr. Opin. Struct. Biol. 1994, 4, 719–728.
8. (a) Roy, R.; Zanini, D. J. Org. Chem. 1996, 61, 7348–
7354;
3,6-Dioxaoct-1,8-diyl-di-(3-O-h-
D
-galacto-
pyranosyl-i- -galactopyranoside) (1).—To a
D
solution of 13 (200 mg, 0.113 mmol) in dry 1:1
MeOH–CH2Cl2 was added a catalytic amount
of NaOMe (pH 12). After stirring at rt for 24
h, the mixture was neutralized with H+ cation-
exchange resin, filtered, and concentrated. The
residue was chromatographed to afford 14 (161
mg, 94%). A mixture of 14 and Pd–C (10% Pd)
in MeOH was stirred for 20 h at 25 °C under
H2. After filtration, the filtrate was evaporated
to afford 1 as a white foamy solid in quantita-
(b) Roy, R. Trends Glycosci. Glyctotechnol. 1996, 8, 79–
99;
(c) Heerze, L. D.; Kelm, M. A.; Talbot, J. A.; Armstrong,
G. D. J. Infect. Dis. 1994, 169, 1291–1296.
9. David, S.; Thieffry, A.; Veyrie`res, A. J. Chem. Soc.
Perkin Trans. 1 1981, 1796–1801.
10. Zhang, Z. Y.; G(ran, M. Carbohydr. Res. 1996, 295,
41–55.
1
11. Li, Z. J.; Huang, H. Q.; Cai, M. S. Carbohydr. Res. 1994,
tive yield, [h]2D6 +95.3° (c 1.0, CH3OH); H
265, 227–236.
NMR (CD3OD): l 5.05 (d, 1 H, J1%,2% 1.8 Hz,
H-1%), 4.35 (d, 1 H, J1,2 7.2 Hz, H-1); 13C NMR
(CD3OD): l 104.9 (C-1), 97.7 (C-1%), 80.0 (C-3),
76.3 (C-5), 72.2 (C-5%), 71.3, 70.9, 70.2, and 69.7
(7 C, OCH2CH2OCH2, C-2, C-2%, C-4%, C-3%),
66.8 (C-4), 62.9 and 62.5 (C-6, C-6%); TOF-MS:
[M+Na]+ 821.2, [M+K]+ 837.4.
12. Li, Z. J.; Huang, H. Q.; Cai, M. S. J. Carbohydr. Chem.
1996, 15, 501–506.
13. Zhu, X. X.; Ding, P. Y.; Cai, M. S. Tetrahedron: Asym-
metry 1996, 7, 2833–2838.
14. Zhu, X. X.; Ding, P. Y.; Cai, M. S. Tetrahedron Lett.
1996, 37, 8549–8552.
15. Zhang, S. Q.; Li, Z. J.; Wang, A. B.; Cai, M. S. Carbo-
hydr. Res. 1998, 308, 281–285.
16. Mao, J. M.; Chen, H. M.; Zhang, J.; Cai, M. S. Synth.
Commun. 1995, 25, 1563–1565.
17. Li, Q.; Li, H.; Cai, M. S.; Li, Z. J.; Zou, R. L. Tetra-
hedron: Asymmetry 1999, 10, 2675–2683.
18. Greilich, U.; Zimmermann, P.; Jung, K. H.; Schmidt, R.
R. Liebigs Ann. Chem. 1993, 859–864.
19. Koto, S.; Morishima, N.; Miyata, Y.; Zen, S. Bull. Chem.
Soc. Jpn. 1976, 49, 2639–2640.
Acknowledgements
This project was supported by the National
Natural Science Foundation of the PR China
.