Efficient synthesis of a 3,6-branched mannose hepta- and octasaccharide

Article abstract of DOI:10.1016/S0008-6215(03)00351-3

α-D-Manp-(1→3)-[α-D-Manp-(1→2)-α -D-Manp-(1→6)]-α-D-Manp-(1→3)-[α-D-Manp-(1→2) -α-D-Manp-(1→6)]-D-Manp and α-D-Manp-(1→2)-α -D-Manp-(1→3)-[α-D-Manp-(1→2)-α-D-Manp-(1→6)] -α-D-Manp-(1→3)-[α-D-Manp-(1→2)-α-D-Manp-(1→6)] -D-Manp, were synthesized as their me

Full text of DOI:10.1016/S0008-6215(03)00351-3

Carbohydrate Research 338 (2003) 2039ꢀ2046
/
www.elsevier.com/locate/carres
Efficient synthesis of a 3,6-branched mannose hepta- and
octasaccharide
Jianjun Zhang, Zuchao Ma, Fanzuo Kong*
Research Center for Eco-Environmental Sciences, Academia Sinica, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China
Received 29 May 2003; accepted 14 July 2003
Abstract
a-
-Manp-(10
-Manp, were synthesized as their methyl glycosides in a regio- and stereoselective way.
2003 Elsevier Ltd. All rights reserved.
D
-Manp-(10
/
3)-[a-
D
-Manp-(10
/
2)-a-
D
-Manp-(10
/
6)]-a-
D
-Manp-(10
/
3)-[a-
D
-Manp-(10
/
2)-a-
D
-Manp-(10
/
6)]-D-Manp and
D
a-
D
/
2)-a-
D
-Manp-(10
/
3)-[a-
D
-Manp-(10
/
2)-a-
D
-Manp-(10
/
6)]-a-
D
-Manp-(10
/
3)-[a-
D
-Manp-(10
/
2)-a-
-Manp-(10
/
6
)]-D
#
Keywords: Oligosaccharide; Mannose; Synthesis
1. Introduction
herein syntheses of the mannose hepta- and octasac-
charide analogues of the N-glycan mannans.
Asparagine-linked glycoprotein oligosaccharides play a
vital role in fundamental biological processes such as
cell differentiation, malignant transformation, viral,
bacterial and parasitic infections and protein transpor-
2
. Results and discussion
1
tations. They are usually divided into three major
subgroups, i.e., high-mannose type, complex type and
hybrid type, and each of them may consist of diverse
8
Our previous communication described an efficient
synthesis of the hexasaccharide repeating unit of the
exopolysaccharide (GXM) from Cryptococcus neofor-
mans serovar A with 4,6-O-isopropylidenated mannose
derivatives as the key synthons. We found that the 4,6-
O-isopropylidenated mannose derivatives were also
appropriate intermediates in the present research for
construction of the required mannose hepta- and
octasaccharides. As outlined in Scheme 3, 1,2,3-tri-O-
2
structures in living cells. A 3,6-branched mannose
nonasaccharide of the N-glycan is expressed on the
3
HIV gp 120 glycoprotein, whereas a 3,6-branched
mannose octasaccharide of the N-glycan exists in the
4
adhesion domain of human CD2 (Scheme 1).
As an ongoing project on the research on structureꢀ
/
bioactivity relationship among oligosaccharides, we
have synthesized (Scheme 2) a variety of naturally
acetyl-4,6-O-isopropylidene-D-mannopyranose (1), ob-
tained from selective 4,6-O-isopropylidenation of man-
9
nose with 2-methoxypropene, followed by acetylation,
was chosen as the starting material. Selective 1-O-
occurring mannose oligosaccharides, such as (10
/
2)-
5
6)-linked mannans and 3,6-branched
branched (10
/
6
mannans, and also a series of artificially designed
7
oligosaccharides. It was interesting to find that some
synthetic glucose oligosaccharides showed excellent
7
bioactivity compared to the natural ones. In continua-
tion of our studies on oligosaccharides, we present
deacetylation with ammonia in THFꢀMeOH, followed
/
1
by trichloroacetimidation with trichloroacetonitrile in
0
the presence of potassium carbonate, gave the donor
,3-di-O-acetyl-4,6-O-isopropylidene-a-D-mannopyra-
nosyl trichloroacetimidate (2). Condensation of 2 with
2
the acceptor, methyl 4,6-O-isopropylidene-a-
D-manno-
3)-linked
pyranoside (3), selectively afforded the (10
/
*
Corresponding author. Tel.: ꢁ
0-62923563.
E-mail address: fzkong@mail.rcees.ac.cn (F. Kong).
/
86-10-62936613; fax: ꢁ86-
/
1
disaccharide 4 (74%). The regioselectivity of the cou-
pling was confirmed by acetylation of 4 to give 5, and
0008-6215/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0008-6215(03)00351-3

2040
J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ2046
/
Scheme 1. Examples of naturally occurring N-glycans Man7, Man8, and Man9.
1
the H NMR spectrum of 5 showed a newly emerged
downfield doublet of doublets at d 5.34 ppm with J1,2
.5 and J2,3 3.0 Hz for H-2 compared to that of 4.
were synthesized in a highly regio- and steroselective
way with a quite simple procedure. Large-scale prepara-
tions should be possible with this method.
ꢂ
/
1
ꢂ
/
Deacetylation of 4 or 5 in a solution of ammonia in
methanol furnished the disaccharide triol acceptor 6 in
high yield. Again, 3-O-selective glycosylation of 6 with
3
. Experimental
the donor, 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
pyranosyl-(102)-3,4,6-tri-O-benzoyl-a- -mannopyra-
3)-linked
D-manno-
/
D
1
1
nosyl trichloroacetimidate (7), yielded (10
/
3
.1. General methods
tetrasaccharide 8 (71%). The 3-O-glycosylation was
1
identified by acetylation to give 9, and the H NMR
spectrum of 9 showed three characteristic signals at d
Melting points were determined with a ‘Mel-Temp’
apparatus. Optical rotations were determined with a
PerkinꢀElmer model 241-MC automatic polarimeter for
solutions in a 1-dm, jacketed cell. H, C, and 2D NMR
spectra were recorded with Varian XL-400 spectro-
meters, for solutions in CDCl or in D O as indicated.
Individual resonances could not identified with the
specific sugar residues. Chemical shifts are expressed in
5
.66 ppm with J1,2
with J1,2 0.8 and J2,3
J1,2 1.0 and J2,3
3.0 Hz for H§-2, H?-2, and H-2,
ꢂ
/
0.7 and J2,3
ꢂ
/
2.7 Hz, 5.41 ppm
/
ꢂ
/
ꢂ
/
3.0 Hz, and 5.11 ppm with
1
13
ꢂ
/
ꢂ
/
respectively. Removal of the O-isopropylidene groups
was smoothly carried out with 90% TFA giving the
tetrasaccharide acceptor 10 (83%). Selective 6-O-glyco-
3
2
1
2
sylation of 10 with the disaccharide donor 7 afforded
octasaccharide 11 (61%), and subsequent acetylation
ppm downfield from the Me Si absorption. Mass
4
spectra were recorded with a VG PLATFORM mass
spectrometer using the ESI mode. Thin-layer chromato-
graphy (TLC) was performed on silica gel HF with
detection by charring with 30% (v/v) sulfuric acid in
methanol or by UV detection. Column chromatography
1
gave 12. The H NMR spectrum of 12 showed eight-
proton signals for H-4 at the region of d 5.2ꢀ6.2,
/
indicating the 6-O-selective glycosylation. Deacylation
of 12 in a saturated solution of ammonia in methanol
furnished the target octasaccharide. The heptasacchar-
ide 20 was obtained in a similar way except that, instead
of the disaccharide donor 7, 2-O-acetyl-3,4,6-tri-O-
was conducted by elution of a column (8ꢃ
40, 18ꢃ300, 35ꢃ400 mm) of silica gel (100ꢀ
mesh) with EtOAcꢀpetroleum ether (bp 60ꢀ90 8C) as
/
100, 16ꢃ
/
2
/
/
/
200
/
/
benzoyl-a-
D-mannopyranosyl trichloroacetimidate (14)
the eluent. Analytical LC was performed with a Gilson
HPLC consisting of a pump (model 306), stainless steel
was used to couple 6. The rest of the steps were exactly
the same as those used for the preparation of 13 from 8.
Bioactivity tests for 13 and 20 are in progress.
column packed with silica gel (Spherisorb SiO , 10ꢃ
/
300
250 mm), differential refractometer (132-RI
Detector), UVꢀVis detector (model 118). EtOAcꢀpet-
roleum ether (bp 60ꢀ90 8C) was used as the eluent at a
2
or 4.6ꢃ
/
In summary, 3,6-branched mannose hepta- and
octasaccharide analogues of the N-glycan mannans
/
/
/
Scheme 2. Synthetic mannose hepta- and octasaccharides.

J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ
/2046
2041
Scheme 3. Reagents and conditions: (a) (i) THFꢀ
equiv), rt, 12 h, 71%. (b) TMSOTf (0.05ꢀ0.10 equiv), 4 A MS, CH Cl , ꢄ
5, 75% for 18). (c) Ac OꢀPyridine, 81ꢀ93%. (d) CH
for 10, 80% for 17.
/
CH
3
OH, 1.5 N NH
3
, rt, 2ꢀ
20 8C, 2ꢀ
OH saturated with ammonia, rt, 12ꢀ
/
3 h; (ii) CH
4 h (74% for 4, 71% for 8, 61% for 11, 67% for
36 h, 73ꢀ96%. (e) 90% TFA, rt, 2 h, 83%
2 2 3 2 3
Cl , CCl CN (2.0 equiv), K CO (2.0
˚
/
/
/
2
2
1
2
/
/
3
/
/
flow rate of 1ꢀ
at a temperature B
/
4 mL/min. Solutions were concentrated
60 8C under diminished pressure.
etherꢀEtOAc) indicated that the reaction was complete.
/
/
The solution was concentrated and dried under high
vacuum giving a white foamy solid. This foamy solid
was dissolved in dry dichloromethane (50 mL), then
trichloroacetonitrile (6.3 mL, 30 mmol) and 1,8-diaza-
bicyclo[5.4.0]undecene (DBU) (0.50 mL, 4.04 mmol)
was added subsequently. The reaction mixture was
stirred under nitrogen for 3 h and then concentrated.
The residue was purified by chromatography (4:1
3.2. 2,3-Di-O-acetyl-4,6-O-isopropylidene-a-
mannopyranosyl trichloroacetimidate (2)
D-
Compound 1 (6.90 g, 20.0 mmol) was dissolved in 1 M
solution of ammoniaꢀmethanol (100 mL) and stirred
for 4 h, at the end of which time TLC (3:1 petroleum
/

2042
J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ2046
/
petroleum etherꢀ
/
EtOAc) to give 2 (7.40 g, 82.2%) as a
1
9.8 Hz, H-3?), 5.12 (d, 1 H, J1,2 1.2 Hz, H-1?), 4.70 (d, 1
H, J1,2 1.5 Hz, H-1), 4.20 (dd, 1 H, J3,4 J4,5 9.9 Hz,
H-4), 4.11ꢀ3.87 (m, 8 H), 3.66 (m, 1 H, H-5), 3.34 (s, 3
H, OCH ), 2.21 (s, 3 H, CH CO), 2.19 (s, 3 H, CH CO),
syrup: [a] ꢁ42.08 (c 1.0, CHCl ); H NMR (400 MHz,
/
ꢂ
/
ꢂ
/
D
3
CDCl ): d 8.72 (s, 1 H, CNHCCL ), 6.17 (s, 1 H, J 1.6
/
3
3
1,2
Hz, H-1), 5.50 (dd, 1 H, J1,21.6 Hz, J2,3 3.4 Hz, H-2),
.30 (dd, 1 H, J2,3 3.4 Hz, J3,4 10.3 Hz, H-3), 4.11 (dd, 1
H, J3,4 10.3 Hz, J4,5 10.0 Hz, H-4), 3.98ꢀ3.85 (m, 3 H),
.20 (s, 3 H, CH CO), 2.04 (s, 3 H, CH CO), 1.55 (s, 3
3
3
3
5
2.14 (s, 3 H, CH CO), 1.55 (s, 3 H, isopropylidene), 1.53
3
/
(s, 3 H, isopropylidene),1.38 (s, 3 H, isopropylidene),
1.31 (s, 3 H, isopropylidene). Anal. Calcd for
C H O : C, 53.37; H, 6.81. Found: C, 53.41; H, 6.62.
2
3
3
H, isopropylidene), 1.42 (s, 3 H, isopropylidene). Anal.
Calcd for C H Cl NO : C, 40.12; H, 4.49. Found: C,
2
5
38 14
1
5
20
3
8
4
0.40; H, 4.73.
3.5. Methyl 4,6-O-isopropylidene-a-
D-mannopyranosyl-
(
103)-4,6-O-isopropylidene-a- -mannopyranoside (6)
/
D
3
.3. Methyl 2,3-di-O-acetyl-4,6-O-isopropylidene-a-
3)-4,6-O-isopropylidene-a-
mannopyranoside (4)
D-
mannopyranosyl-(10
/
D-
Disaccharide 4 (2.60 mg, 5.0 mmol) was dissolved in a
satd solution of ammonia in methanol (25 mL). After 2
h at rt, the reaction mixture was concentrated, and the
residue was purified by flash column chromatography
on a silica gel column (EtOAc) to give compound 6 (2.10
To a cooled solution (ꢄ
/
20 8C) of 3 (1.17 g, 5.0 mmol)
and 2 (2.46 g, 5.5 mmol) in anhyd CH Cl (50 mL) was
added TMSOTf (18 mL, 0.05 mmol). The mixture was
stirred at this temperature for 2 h, and then quenched
2
2
g, 96.3%) as a foamy solid: [a] ꢁ
H NMR (400 MHz, CDCl ): d 5.21 (s, 1 H, H-1?), 4.69
/
90.68 (c 0.5, CHCl3);
D
1
3
with Et N (two drops). The solvents were evaporated in
3
(s, 1 H, H-1), 3.34 (s, 3 H, CH CO), 1.52 (s, 3 H,
isopropylidene), 1.49 (s, 3 H, isopropylidene), 1.43 (s, 3
3
vacuo to give a residue, which was purified by silica gel
1
3
column chromatography (2:1 petroleum etherꢀ
/EtOAc)
H, isopropylidene), 1.37 (s, 3 H, isopropylidene);
C
NMR (100 MHz, CDCl ): d 101.4, 101.3 (2 C, 2
to give disaccharide 4 (1.93 g, 74.2%) as a syrup: [a] ꢁ
/
D
3
1
4
3.38 (c 1.0, CHCl ); H NMR (400 MHz, CDCl ): d
Me CO ), 100.2, 99.8 (2 C, 2 C-1), 73.6, 71.4, 71.3,
2
3
3
2
5
.36 (dd, 1 H, J1,2 1.0 Hz, J2,3 3.2 Hz, H-2?), 5.21 (dd, 1
71.2, 70.9, 68.9, 64.7, 64.3, 62.3, 62.2 (10 C, C2ꢀ
C2?ꢀ6?), 54.9 (OCH ), 29.3, 29.2, 19.4, 19.3 [4 C, 2
(CH ) CO ]. Anal. Calcd for C H O : C, 52.28; H,
/
6,
H, J2,3 3.2 Hz, J3,4 9.9 Hz, H-3?), 5.20 (d, 1 H, J1,2 1.0
Hz, H-1?), 4.73 (d, 1 H, J1,2 1.1 Hz, H-1), 4.14 (dd, 1 H,
/
3
3 2
2
19 32 11
J3,4
H, J2,3 3.3 Hz, J3,4 10.0 Hz, H-3), 3.87ꢀ
.60 (m, 1 H, H-5), 3.36 (s, 3 H, OCH ), 2.17 (s, 3 H,
ꢂ
/
J4,5
ꢂ
/
9.9 Hz, H-4), 4.06ꢀ
/
4.02 (m, 2 H), 3.95 (dd, 1
7.39. Found: C, 52.51; H, 7.67.
/
3.76 (m, 5 H),
3
3.6. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(102)-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(10
mannopyranosyl-(10
mannopyranoside (8)
D-
3
CH CO), 2.15 (s, 3 H, CH CO), 1.52 (s, 6 H, isopropy-
3
/
D-
3
lidene), 1.40 (s, 3 H, isopropylidene), 1.29 (s, 3 H,
/
3)-4,6-O-isopropylidene-a-
D
-
-
1
isopropylidene); C NMR (100 MHz, CDCl ): 170.0,
3
/
3)-4,6-O-isopropylidene-a-
D
3
1
1
7
69.6 (2 C, 2 COCH ), 101.4 (1 C, Me CO ), 100.1,
3 2 2
00.0 (2 C, 2 C-1), 99.5 (1 C, Me CO ), 74.1, 71.6, 71.1,
2
2
0.0, 68.9, 68.6, 65.4, 64.2, 62.4, 62.2 (10 C, C2ꢀ
/6,
To a cooled solution (ꢄ
/
20 8C) of 6 (2.18 g, 5 mmol) and
C2?ꢀ
/
6?), 54.9 (OCH ), 29.1, 29.0, 20.8, 20.7 [4 C, 2
7 (6.34 g, 5.5 mmol) in anhyd CH Cl (50 mL) was
added TMSOTf (18 mL, 0.05 mmol). The mixture was
stirred at this temperature for 2 h and then quenched
3
2
2
(
C H O : C, 53.07; H, 6.97. Found: C, 53.32; H, 6.70.
CH ) CO ], 19.3, 19.1 (2 C, 2 COCH ). Anal. Calcd for
3
2
2
3
2
3
36 13
with Et N (two drops). The solvents were evaporated in
3
3
.4. Methyl 2,3-di-O-acetyl-4,6-O-isopropylidene-a-
mannopyranosyl-(103)-2-O-acetyl-4,6-O-
isopropylidene-a- -mannopyranoside (5)
D-
vacuo to give a residue, which was purified by silica gel
EtOAc)
/
column chromatography (1:1 petroleum etherꢀ
/
D
to give trisaccharide 8 (5.08 g, 71.2%) as a syrup: [a] ꢁ
/
D
1
4
1.08 (c 1.0, CHCl ); H NMR (CDCl , 400 MHz): d
3
3
To a solution of 4 (104 mg, 0.2 mmol) in pyridine (5 mL)
was added acetic anhydride (2.0 mL, 2 mmol). The
reaction mixture was stirred at room temperature (rt)
for 12 h, at the end of which time TLC (3:1 petroleum
8.05ꢀ
9.8 Hz, H-3), 5.96 (dd, 1 H, J3,4
5.88 (dd, 1 H, J2,3 3.1, J3,4 9.9 Hz, H-3), 5.85 (dd, 1 H,
J3,4 J4,5 9.9 Hz, H-4), 5.66 (d, 1 H, J1,2 1.5 Hz, H-1),
/
7.33 (m, 30 H, 6 PhH), 5.98 (dd, 1 H, J2,3 3.1, J3,4
ꢂ
/
J4,5 9.8 Hz, H-4),
ꢂ
/
ꢂ
/
ꢂ
/
etherꢀ
/
EtOAc) indicated that the reaction was complete.
5.64 (dd, 1 H, J1,2 1.6, J2,3 3.1 Hz, H-2), 5.36 (d, 1 H, J1,2
0.8 Hz, H-1), 5.13 (d, 1 H, J1,2 1.4 Hz, H-1), 4.72 (d, 1 H,
The reaction mixture was concentrated, and then the
residue was purified by flash column chromatography
J1,2 1.0 Hz, H-1), 3.37 (s, 3 H, OCH ), 2.03 (s, 3 H,
3
on a silica gel column (3:1 petroleum etherꢀ
/
EtOAc) to
COCH ), 1.49, 1.46, 1.39, 1.34 (4 s, 12 H, isopropyli-
3
1
dene); C NMR (100 MHz, CDCl ): d 169.3 (COCH ),
3
give compound 5 (100 mg, 89.3%) as a foamy solid: [a]D
1
3
3
ꢁ
/
38.98 (c 1.5, CHCl ); H NMR (400 MHz, CDCl ): d
166.5, 166.1, 165.6, 165.4,165.2, 164.9 (6 C, 6 COPh),
101.2, 100.6 (2 C, 2 Me C), 99.8, 99.5, 99.3, 99.1 (4 C, 4
3
3
5.37 (dd, 1 H, J1,2 1.2 Hz, J2,3 3.3 Hz, H-2?), 5.34 (dd, 1
H, J1,2 1.5, J2,3 3.0 Hz, H-2), 5.26 (dd, 1 H, J2,3 3.3, J3,4
2
C-1), 54.8 (OCH ), 29.2, 29.1 (2 C, CH CCH ), 20.5
3
3
3

J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ
/2046
2043
(COCH ), 19.3, 19.2 (2 C, CH CCH ). Anal. Calcd for
C H O : C, 63.10; H, 5.51. Found: C, 63.35; H, 5.69.
J1,2 1.5, J2,3 3.1 Hz, H-2), 5.20 (dd, 1 H, J1,2 1.0, J2,3 3.1
Hz, H-2), 5.12 (d, 1 H, J1,2 1.5 Hz, H-1), 5.09 (d, 1 H,
J1,2 0.8 Hz, H-1), 4.67 (d, 1 H, J1,2 0.9 Hz, H-1), 3.36 (s,
3
3
3
7
5
78 28
1
3
3
.7. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
D-
3 H, OCH ), 2.15, 2.11, 2.00 (3 s, 9 H, 3 COCH );
3
C
3
mannopyranosyl-(10
mannopyranosyl-(10
isopropylidene-a-
,6-O-isopropylidene-a-
/
2)-3,4,6-tri-O-benzoyl-a-
D
-
NMR (100 MHz, CDCl ): d 170.7, 170.2, 169.2 (3 C, 3
3
/
3)-2-O-acetyl-4,6-O-
COCH ), 167.2, 166.8, 165.5, 165.4,165.3, 165.0 (6 C, 6
3
D
-mannopyranosyl-(10
/
3)-2-O-acetyl-
COPh), 100.5, 99.9, 98.7, 98.4 (4 C, 4 C-1), 55.0
4
D-mannopyranoside (9)
(OCH ), 21.0, 20.8, 20.5 (3 C, 3 COCH ). Anal. Calcd
3 3
for C H O : C, 61.25; H, 5.21. Found: C, 61.45; H,
7
3
74 30
To a solution of 8 (2.85 g, 2.0 mmol) in pyridine (30 mL)
was added acetic anhydride (20 mL, 20 mmol). The
reaction mixture was stirred at rt for 12 h, at the end of
5.40.
which time TLC (3:1 petroleum etherꢀEtOAc) indicated
/
3
.9. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
2)-3,4,6-tri-O-benzoyl-a-
3)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
-mannopyranosyl-(102)-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(106)]-2-O-acetyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2-O-acetyl-a-
mannopyranoside (11)
D-
that the reaction was complete. The reaction mixture
was concentrated, and then the residue was purified by
flash column chromatography on a silica gel column
mannopyranosyl-(10
mannopyranosyl-(10
a-
/
D-
/
D
/
D-
(
3:1 petroleum etherꢀ/EtOAc) to give compound 9 (2.81
/
D-
g, 93.7%) as a foamy solid: [a] ꢁ
/
42.68 (c 1.0, CHCl3);
D
1
/
H NMR (CDCl , 400 MHz): d 8.13ꢀ
/7.29 (m, 30 H, 6
3
D
/
D-
PhH), 6.14 (dd, 1 H, J3,4
H, J3,4 J4,5
J3,4 9.9 Hz, H-3), 5.72 (dd, 1 H, J2,3 2.4, J3,4 9.9 Hz, H-
), 5.66 (dd, 1 H, J1,2 0.7, J2,3 2.7 Hz, H-2), 5.49 (d, 1 H,
J1,2 0.7, H-1), 5.41 (dd, 1 H, J1,2 0.8, J2,3 3.0 Hz, H-2),
ꢂ/J4,5
ꢂ/9.9 Hz, H-4), 5.99 (dd,
/
D-
1
ꢂ
/
ꢂ9.9 Hz, H-4), 5.83 (dd, 1 H, J2,3 2.7,
/
3
Compound 10 (715 mg, 0.5 mmol) and 7 (1.15 g, 1.0
mmol) were dried together under high vacuum for 2 h,
5
.22 (d, 1 H, J1,2 0.7 Hz, H-1), 5.11 (dd, 1 H, J1,2 1.0, J2,3
.0 Hz, H-2), 5.10 (d, 1 H, J1,2 1.0 Hz, H-1), 4.64 (d, 1 H,
then dissolved in anhyd CH Cl (50 mL). TMSOTf (18.0
2
3
J1,2 0.8 Hz, H-1), 3.36 (s, 3 H, OCH ), 2.32, 2.18, 2.01 (3
2
mL, 0.10 mmol) was added dropwise at ꢄ
/
20 8C with N
3
2
s, 9 H, 3 COCH ), 1.53, 1.49, 1.38, 1.32 (4 s, 12 H,
3
protection. The reaction mixture was stirred for 2 h,
during which time the temperature was gradually
warmed to ambient temperature. Then the mixture
1
isopropylidene); C NMR (100 MHz, CDCl ): d 170.2,
3
3
1
70.2, 169.9 (3 C, 3 COCH ), 166.4, 165.8, 165.5,
3
1
65.3,165.0, 164.9 (6 C, 6 COPh), 99.9, 99.7 (2 C, 2
Me C), 99.8, 99.4, 99.3, 99.0 (4 C, 4 C-1), 55.0 (OCH ),
was neutralized with Et N and concentrated to dryness
3
2
3
under reduced pressure. Purification of the residue by
column chromatography on a silica gel column (1:1
2
COCH ), 19.4, 19.2 (2 C, CH CCH ). Anal. Calcd for
9.1, 29.0 (2 C, CH CCH ), 20.9, 20.9, 20.5 (3 C, 3
3 3
3
3
3
petroleum etherꢀ
/
EtOAc) furnished the octasaccharide
28.58 (c 1.0,
CHCl ); H NMR (CDCl , 400 MHz): d 8.09ꢀ7.25 (m,
5.67 (m, 5
C H O : C, 62.77; H, 5.47. Found: C, 62.48; H, 5.33.
7
9
82 30
11 (1.03 g, 60.9%) as a syrup: [a]D
ꢁ
/
1
/
3
3
3
.8. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
D-
9
0 H, 18 PhH), 6.04ꢀ
/
5.84 (m, 10 H), 5.73ꢀ
/
mannopyranosyl-(10
mannopyranosyl-(10
mannopyranosyl-(10
mannopyranoside (10)
/
2)-3,4,6-tri-O-benzoyl-a-D-
H), 5.61 (dd, 1 H, J1,2 1.0, J2,3 3.1 Hz, H-2), 5.34 (d, 1 H,
/
3)-2-O-acetyl-a-
D
-
-
J1,2 0.7 Hz, H-1), 5.30 (dd, 1 H, J1,2 1.1, J2,3 3.2 Hz, H-
/
3)-2-O-acetyl-a-
D
2
), 5.27 (d, 1 H, J1,2 1.1 Hz, H-1), 5.24 (d, 1 H, J1,2 1.0
Hz, H-1), 5.14 (d, 1 H, J1,2 1.2 Hz, H-1), 5.08 (d, 1 H,
J1,2 1.2 Hz, H-1), 5.07 (d, 1 H, J1,2 0.8 Hz, H-1), 4.86ꢀ
.75 (m, 2 H), 4.70 (d, 1 H, J1,2 0.8 Hz, H-1), 4.61 (d, 1
H, J1,2 0.9 Hz, H-1), 3.35 (s, 3 H, OCH ), 2.16, 2.12,
/
Compound 9 (1.51 g, 1.0 mmol) was dissolved in 90%
TFA (20 mL) and stirred for 2 h, at the end of which
time the reaction mixture was poured directly into
toluene (100 mL), and then the mixture was concen-
trated. The residue was purified by flash chromatogra-
4
3
1
3
2
.01, 1.99, 1.96 (5 s, 15 H, 5 COCH3); C NMR (100
MHz, CDCl ): d 170.5, 170.2, 169.2, 169.2, 169.1 (5 C, 5
3
COCH ), 167.2, 166.5, 165.4, 165.3,165.2, 165.9, 165.6,
3
phy (EtOAc) to give 10 (1.19 g, 83.2%) as a syrup: [a]D
1
1
1
65.6, 165.5, 165.5, 165.4, 165.3, 165.3, 165.2, 165.2,
ꢁ
/
30.18 (c 1.0, CHCl ); H NMR (CDCl , 400 MHz): d
3
3
65.1, 165.0, 164.9 (18 C, 18 COPh), 100.6, 100.0, 99.8,
7
9
5
.95ꢀ
.7 Hz, H-4), 5.88 (dd, 1 H, J3,4
.84 (dd, 1 H, J2,3 3.2, J3,4 9.8 Hz, H-3), 5.68 (dd, 1 H,
/
7.25 (m, 30 H, 6 PhH), 5.95 (dd, 1 H, J3,4
ꢂ
/
J4,5
ꢂ
/
ꢂ
/
J4,5 9.8 Hz, H-4),
ꢂ
/
99.7, 99.4, 98.9, 98.6, 98.3 (8 C, 8 C-1), 54.9 (OCH
21.0, 20.8, 20.5 (5 C, 5 COCH ). Anal. Calcd for
64: C, 65.09; H, 4.90. Found: C, 65.25; H,
3
),
3
J2,3 3.0, J3,4 9.7 Hz, H-3), 5.63 (dd, 1 H, J1,2 1.4, J2,3 3.1
Hz, H-2), 5.56 (d, 1 H, J1,2 1.4 Hz, H-1), 5.50 (dd, 1 H,
C H O
185 166
4.79.

2044
J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ2046
/
3
.10. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(102)-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2,4-di-O-acetyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2,4-di-O-acetyl-a-
mannopyranoside (12)
D
-
3.12. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-D-
/
D-
mannopyranosyl-(10
mannopyranosyl-(10
mannopyranoside (15)
/
3)-4,6-O-isopropylidene-a-
D
-
-
/
/
3)-4,6-O-isopropylidene-a-
D
D
/
D-
/
D-
/
To a cooled solution (ꢄ
/
20 8C) of 6 (2.18 g, 5 mmol) and
Cl (50 mL) was
D
/
D-
14 (3.73 g, 5.5 mmol) in anhyd CH
added TMSOTf (18 mL, 0.05 mmol). The mixture was
stirred at this temperature for 2 h, and then quenched
2
2
/
D-
with Et N (two drops). The solvents were evaporated in
3
To a solution of 11 (1.02 g, 0.3 mmol) in pyridine (20
mL) was added acetic anhydride (10 mL, 10 mmol). The
reaction mixture was stirred at rt for 12 h, at the end of
vacuo to give a residue, which was purified by silica gel
column chromatography (1:1 petroleum etherꢀ
/
EtOAc)
to give trisaccharide 15 (3.20 g, 67.2%) as a syrup: [a]
D
1
which time TLC (1:1 petroleum etherꢀ
/
EtOAc) indicated
ꢁ
/
91.78 (c 1.0, CHCl
); H NMR (CDCl , 400MHz): d
3 3
7
1
5
1
.95ꢀ
/
7.34 (m, 15 H, 3 PhH), 5.94 (dd, 1 H, J3,4
ꢂ
/
J4,5
ꢂ
/
that the reaction was complete. The reaction mixture
was concentrated, and then the residue was purified by
flash column chromatography on a silica gel column
0.0 Hz, H-4), 5.75 (dd, 1 H, J2,3 3.3, J3,4 10.0 Hz, H-3),
.53 (dd, 1 H, J1,2 1.8, J2,3 3.3 Hz, H-2), 5.43 (d, 1 H, J1,2
.8 Hz, H-1), 5.31 (d, 1 H, J1,2 1.0 Hz, H-1), 4.71 (d, 1 H,
(
mg, 91.8%) as a foamy solid: [a]D
1:1 petroleum etherꢀ
/
EtOAc) to give compound 12 (964
J2,1 1.0 Hz, H-1), 4.66ꢀ
/
4.58 (m, 3 H), 4.26ꢀ/4.18 (m, 4
ꢁ33.08 (c 0.3,
/
1
CHCl ); H NMR (CDCl , 400 MHz): d 6.14 (dd, 1
H), 4.04ꢀ3.99 (m, 2 H), 3.90ꢀ
/
/
3.82 (m, 4 H), 3.68ꢀ
/3.63
3
3
(
m, 2 H), 3.36 (s, 3 H, OCH ), 2.17 (s, 3 H, COCH ),
3
H, J3,4
ꢂ
/
J4,5
ꢂ
/
9.8 Hz, H-4), 6.05 (dd, 1 H, J3,4
ꢂ
/
J4,5
ꢂ
/
3
1.56, 1.45 (2 s, 6 H, isopropylidene), 1.37 (s, 6 H,
isopropylidene); C NMR (100 MHz, CDCl ): d 169.5
(
9
.9 Hz, H-4), 6.01 (dd, 1 H, J3,4
.99 (dd, H, J3,4 J4,5 9.8 Hz, H-4), 5.96 (dd, 1 H,
J4,5 10.0 Hz, H-4), 5.91 (dd, H, J3,4 J4,5 9.9
Hz, H-4), 5.90ꢀ5.80 (m, 5 H), 5.75 (dd, 1 H, J2,3 3.0, J3,4
.7 Hz, H-3), 5.68ꢀ5.64 (m, 3 H), 5.38 (d, 1 H, J1,2 0.7
Hz, H-1), 5.38 (dd, 1 H, J3,4 J4,5 10.0 Hz, H-4), 5.33
dd, 1 H, J1,2 1.0, J2,3 3.1 Hz, H-2), 5.30 (dd, 1 H, J3,4
J4,5 10.0 Hz, H-4), 5.24 (d, 2 H, J1,2 1.4, 2 H-1), 5.19
d, 1 H, J1,2 0.8 Hz, H-1), 5.14ꢀ5.08 (m, 4 H, 3 H-1, H-
ꢂ
/
J4,5
ꢂ/9.8 Hz, H-4),
1
3
5
ꢂ
/
ꢂ
/
3
COCH ), 166.3, 165.6, 163.6 (5 C, 5 COPh), 101.2,
3
J3,4
ꢂ
/
ꢂ
/
ꢂ
/
ꢂ
/
1
00.8, (2 C, 2 Me C) 99.9, 99.4, 98.3 (3 C, 3 C-1), 54.8
2
/
(OCH ), 29.1, 28.9 (2 C, CH CCH ), 20.6 (COCH ),
3 3 3 3
9
/
19.2, 19.0 (2 C, CH CCH ). Anal. Calcd for C H O :
C, 60.50; H, 5.92. Found: C, 60.45; H, 5.66.
ꢂ
/
ꢂ
/
3 3 48 56 20
(
ꢂ
/
ꢂ
/
3
.13. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(103)-2-O-acetyl-4,6-O-
isopropylidene-a- 3)-2-O-acetyl-
-mannopyranosyl-(10
,6-O-isopropylidene-a- -mannopyranoside (16)
D-
(
/
/
2
), 4.73 (d, 1 H, J1,2 1.3 Hz, H-1), 3.33 (s, 3 H, OCH3),
D
/
2.24, 2.16, 2.08, 2.06, 1.99, 1.98, 1.96 (7 s, 21 H, 7
COCH ). Anal. Calcd for C189H170O : C, 64.90; H,
4
D
3
66
4
.90. Found: C, 64.75; H, 4.81.
To a solution of 15 (950 mg, 1.0 mmol) in pyridine (50
mL) was added acetic anhydride (20 mL, 20 mmol). The
reaction mixture was stirred at rt for 12 h, at the end of
3
.11. Methyl a-
D
-mannopyranosyl-(10
3)-[a-
-mannopyranosyl-(106)]-a-
a-
-mannopyranosyl-(10
)]-a-
/
2)-a-D-
which time TLC (3:1 petroleum etherꢀEtOAc) indicated
/
mannopyranosyl-(10
D
/
D
-mannopyranosyl-(10
/
2)-a-
-mannopyranosyl-(103)-
-mannopyranosyl-(10
that the reaction was complete. The reaction mixture
was concentrated, and then the residue was purified by
flash column chromatography on a silica gel column
/
D
/
[
D
/
2)-a-
D
/
6
D-mannopyranoside (13)
(3:1 petroleum etherꢀ/EtOAc) to give compound 16 (830
mg, 80.6%) as a foamy solid: [a]D
1
ꢁ
/
82.68 (c 1.0,
Octasaccharide 12 (700 mg, 0.20 mmol) was dissolved in
a saturated solution of ammonia in MeOH (30 mL).
After 96 h at rt, the reaction mixture was concentrated,
and the residue was purified by chromatography on
CHCl3); H NMR (CDCl , 400 MHz): d 8.10ꢀ
/7.23
3
(m, 65 H, 13 PhH), 6.04 (dd, 1 H, J3,4
ꢂ/J4,5
ꢂ/10.0 Hz,
H-4), 5.64 (dd, 1 H, J2,3 3.2, J3,4 10.0 Hz, H-3), 5.45 (dd,
1 H, J1,2 1.8, J2,3 2.9 Hz, H-2), 5.40 (dd, 1 H, J1,2 1.3, J2,3
3.4 Hz, H-2), 5.32 (d, 1 H, J1,2 1.8 Hz, H-1), 5.22 (dd, 1
H, J1,2 1.3, J2,3 2.9 Hz, H-2), 5.10 (d, 1 H, J1,2 1.3 Hz, H-
1), 4.67 (dd, 1 H, J2,3 2.9, J3,4 12.1 Hz, H-3), 4.63 (d, 1
Sephadex LH-20 (H O) to afford 13 (193 mg, 72.6%) as
2
1
a foamy solid: H NMR (D O, 400 MHz): d 5.24 (s, 1
2
H, H-1), 5.02 (s, 2 H, 2 H-1), 4.91 (d, 2 H, J1,2 1.2 Hz, 2
H-1), 4.90 (s, 1 H, H-1), 4.87 (s, 1 H, H-1), 4.61 (s, 1 H,
H, J1,2 1.3 Hz, H-1), 4.46ꢀ
H), 3.87ꢀ3.81 (m, 4 H), 3.70ꢀ
OCH ), 2.31, 2.18, 2.07 (3 s, 9 H, 3 COCH ), 1.56, 1.52
/
4.38 (m, 2 H), 4.09ꢀ
/4.05 (m, 4
1
H-1), 3.29 (s, 3 H, OCH3); C NMR (100 MHz, D O):
3
2
/
/3.60 (m, 2 H), 3.36 (s, 3 H,
d 105.1, 105.1, 104.9, 104.9, 104.9, 103.6, 103.4, 100.6,
1
3
3
00.5 (8 C, 8 C-1), 57.5 (OCH ). MALDI-TOF MS
3
(2 s, 6 H, isopropylidene), 1.37 (s, 6 H, isopropylidene).
Anal. Calcd for C H O : C, 60.22; H, 5.83. Found: C,
60.47; H, 5.61.
Calcd for C H O : 1329.2 [M]. Found: 1352.1 [Mꢁ
/
4
9
84 41
52 60 22
ꢁ
Na ].

J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ
/2046
2045
3
.14. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
D-
166.5, 166.3, 166.2,165.9, 165.6, 165.6, 165.5, 165.4,
165.4, 165.3, 165.3, 165.2, 165.0, 164.9 (15 C, 15 COPh),
100.1, 99.8, 99.7, 98.9, 98.7, 98.6, 98.3 (7 C, 7 C-1), 54.9
(OCH ), 21.8, 20.7, 20.6, 20.5, 20.5 (5 C, 5 COCH ).
mannopyranosyl-(10
mannopyranosyl-(10
mannopyranoside (17)
/
3)-2-O-acetyl-a-
D
-
-
/
3)-2-O-acetyl-a-
D
3
3
Anal. Calcd for C158H144O : C, 64.57; H, 4.94. Found:
56
Compound 16 (1.04 g, 1 mmol) was dissolved in 90%
TFA (20 mL) and stirred for 2 h, at the end of which
time the reaction mixture was poured directly into
toluene (100 mL), and then the mixture was concen-
trated. The residue was purified by flash chromatogra-
C, 64.30; H, 4.88.
3.16. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2,4-di-O-acetyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2,4-di-O-acetyl-a-
mannopyranoside (19)
D-
/
D
/
D-
phy (EtOAc) to give 17 (765 mg, 80.1%) as a syrup: [a]D
1
/
D-
ꢁ
/
35.38 (c 1.0, CHCl ); H NMR (CDCl , 400 MHz): d
/
3
3
7
9
5
.97ꢀ
/
7.26 (m, 10 H, 2 PhH), 5.94 (dd, 1 H, J3,4
ꢂ
/
J4,5
ꢂ
/
D
/
D-
.8 Hz, H-4), 5.61 (dd, 1 H, J2,3 3.2, J3,4 9.8 Hz, H-3),
.51 (dd, 1 H, J1,2 1.0, J2,3 3.2 Hz, H-2), 5.13 (dd, 1 H,
/
D-
J1,2 0.7, J2,3 3.0 Hz, H-2), 5.35 (d, 1 H, J1,2 1.0 Hz, H-1),
5
.19 (dd, 1 H, J1,2 0.8, J2,3 3.1 Hz, H-2), 5.13 (d, 1 H, J1,2
.7 Hz, H-1), 4.66 (d, 1 H, J1,2 0.8 Hz, H-1), 3.36 (s, 3 H,
To a solution of 18 (880 mg, 0.3 mmol) in pyridine (20
mL) was added acetic anhydride (10 mL, 10 mmol). The
reaction mixture was stirred at rt for 12 h, at the end of
0
OCH ), 2.20, 2.12, 2.09 (3 s, 9 H, 3 COCH ); C NMR
1
3
3
3
(
100 MHz, CDCl ): 170.7, 170.5, 170.0 (3 C, 3 COCH ),
3
which time TLC (1:1 petroleum etherꢀEtOAc) indicated
/
3
1
5
66.8, 165.5 (2 C, 2 COPh), 99.9, 98.8, 98.5 (3 C, 3 C-1),
5.0 (OCH ), 20.9, 20.8, 20.6 (3 C, 3 COCH ). Anal.
Calcd for C H O : C, 57.73; H, 5.48. Found: C,
that the reaction was complete. The reaction mixture
was concentrated, and then the residue was purified by
flash column chromatography on a silica gel column
3
3
4
6
52 22
5
7.57; H, 5.62.
(1:1 petroleum etherꢀ/EtOAc) to give compound 19 (729
mg, 80.5%) as a foamy solid: [a]D
1
ꢁ
/
23.28 (c 0.3,
3
.15. Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
3)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
-mannopyranosyl-(102)-3,4,6-tri-O-benzoyl-a-
mannopyranosyl-(106)]-2-O-acetyl-a-
mannopyranosyl-(103)-[2-O-acetyl-3,4,6-tri-O-benzoyl-
a- 2)-3,4,6-tri-O-benzoyl-a-
-mannopyranosyl-(10
mannopyranosyl-(106)]-2-O-acetyl-a-
mannopyranoside (18)
D
-
CHCl3); H NMR (CDCl , 400 MHz): d 8.08ꢀ
/7.25
3
mannopyranosyl-(10
a-
/
(m, 75 H, 15 PhH), 6.06 (dd, 1 H, J3,4
H-4), 6.05 (dd, 1 H, J3,4
ꢂ/J4,5
ꢂ/10.0 Hz,
D
/
D
-
ꢂ/J4,5
ꢂ
/
9.9 Hz, H-4), 6.00ꢀ5.85
/
/
D
-
(m, 6 H), 5.82 (dd, 1 H, J2,3 3.2, J3,4 10.0 Hz, H-3), 5.69
(dd, 1 H, J2,3 3.1, J3,4 9.8 Hz, H-3), 5.66 (dd, 1 H, J1,2
1.1, J2,3 3.2 Hz, H-2), 5.64 (dd, 1 H, J1,2 1.0, J2,3 3.0 Hz,
/
D
/
D-
/
D-
H-2), 5.43 (dd, 1 H, J3,4
1 H, J1,2 1.3, J2,3 3.1 Hz, H-2), 5.31 (dd, 1 H, J1,2 1.5, J2,3
.2 Hz, H-2), 5.30 (dd, 1 H, J3,4 J4,5 10.2 Hz, H-4),
ꢂ
/
J4,5
ꢂ/10.0 Hz, H-4), 5.34 (dd,
3
ꢂ
/
ꢂ
/
Compound 17 (478 mg, 0.5 mmol) and 7 (1.15 g, 1.0
mmol) were dried together under high vacuum for 2 h,
then dissolved in anhyd CH Cl (50 mL). TMSOTf (18.0
5.23 (d, 2 H, J1,2 1.3 Hz, 2 H-1), 5.20 (d, 2 H, J1,2 1.4 Hz,
2 H-1), 5.09 (dd, 1 H, J1,2 1.1, J2,3 3.0 Hz, H-2), 5.09 (d,
H, J1,2 1.3 Hz, H-1), 5.06 (d, H, J1,2 1.1 Hz, H-1), 4.74
2
2
mL, 0.10 mmol) was added dropwise at ꢄ
/
20 8C with N2
(d, 1 H, J1,2 1.0 Hz, H-1), 3.30 (s, 3 H, OCH ), 2.23,
3
protection. The reaction mixture was stirred for 2 h, and
was neutralized with Et N. Then the mixture was
2.16, 2.14, 2.14, 2.09, 2.00, 1.98 (7 s, 21 H, 7 COCH3).
Anal. Calcd for C162H148O : C, 64.36; H, 4.94. Found:
C, 64.50; H, 5.13.
3
58
concentrated to dryness under reduced pressure. Pur-
ification of the residue by column chromatography on a
silica gel column (1:1 petroleum etherꢀ
/
EtOAc) furn-
3.17. Methyl a-
D
-mannopyranosyl-(10
2)-a-
-mannopyranosyl-(103)-[a-
/
3)-[a-D-
ished the heptasaccharide 18 (1.10 g, 74.8%) as a syrup:
1
mannopyranosyl-(10
D
/
D
-mannopyranosyl-(10
/
6)]-a-
-mannopyranosyl-(102)-
-mannopyranoside (20)
[
a]D
ꢁ
/
24.58 (c 1.0, CHCl ); H NMR (CDCl , 400
/
D
/
3
3
MHz): d 8.03ꢀ
/
7.26 (m, 75 H, 15 PhH), 6.00ꢀ
/5.83 (m, 9
a-D-mannopyranosyl-(10
/
6)]-a-D
H), 5.69 (dd, 1 H, J2,3 3.1, J3,4 10.1 Hz, H-3), 5.67ꢀ
/
5.66
m, 2 H), 5.59 (dd, 1 H, J1,2 1.2, J2,3 2.9 Hz, H-2), 5.56
dd, 1 H, J1,2 0.8, J2,3 2.7 Hz, H-2), 5.41 (d, 1 H, J1,2 0.8,
(
(
Octasaccharide 19 (604 mg, 0.20 mmol) was dissolved in
a saturated solution of ammonia in MeOH (30 mL).
After 96 h at rt, the reaction mixture was concentrated,
and the residue was purified by chromatography on
H-1), 5.33 (d, 1 H, J1,2 1.0 Hz, H-1), 5.28 (dd, 1 H, J1,2
.3, J2,3 3.1 Hz, H-2), 5.28 (d, 1 H, J1,2 1.3 Hz, H-1), 5.26
d, 1 H, J1,2 0.8 Hz, H-1), 5.10 (d, 1 H, J1,2 1.0 Hz, H-1),
.07 (d, 1 H, J1,2 0.8 Hz, H-1), 4.71 (d, 1 H, J1,2 1.0 Hz,
H-1), 3.33 (s, 3 H, OCH ), 2.17, 2.11, 2.09, 2.01, 2.00 (5
1
(
5
Sephadex LH-20 (H O) to afford 20 (173 mg, 74.6%) as
2
1
a foamy solid: H NMR (D O, 400 MHz): d 5.01 (s, 2
2
H, 2 H-1), 4.99 (d, 1 H, J1,2 0.6 Hz, H-1), 4.91 (d, 1 H,
J1,2 1.2 Hz, H-1), 4.89 (d, 1 H, J1,2 1.2 Hz, H-1), 4.86 (d,
1 H, J1,2 1.2 Hz, H-1), 4.59 (d, 1 H, J1,2 0.8 Hz, H-1),
3
1
3
s, 15 H, 5 COCH3); C NMR (100 MHz, CDCl ): d
3
1
70.4, 170.3, 169.7, 169.2, 169.2 (5 C, 5 COCH ), 166.8,
3

2046
J. Zhang et al. / Carbohydrate Research 338 (2003) 2039ꢀ2046
/
1
.28 (s, 3 H, OCH3); C NMR (100 MHz, D O): d
3
3
1
1
5. (a) Ning, J.; Kong, F. Tetrahedron Lett. 1999, 1357ꢀ
360;
b) Heng, L.; Ning, J.; Kong, F. Carbohydr. Res. 2001,
331, 431ꢀ438;
c) Ning, J.; Heng, L.; Kong, F. Tetrahedron Lett. 2002,
73ꢀ675.
. (a) Zhang, J.; Kong, F. Tetrahedron: Asymmetry 2002, 13,
43ꢀ252;
b) Zhu, Y.; Kong, F. Synlett 2001, 1217ꢀ
c) Zhu, Y.; Kong, F. Synlett 2000, 1783ꢀ1787;
d) Du, Y.; Zhang, M.; Kong, F. Tetrahedron 2001, 57,
757ꢀ1763;
e) Zhu, Y.; Chen, L.; Kong, F. Chin. J. Chem. 2001, 19,
289ꢀ1295.
/
2
1
05.1, 105.1, 105.0, 104.9, 103.6, 100.6, 100.5 (7 C, 7 C-
), 57.5 (OCH3). MALDI-TOF MS Calcd for
(
ꢁ
/
C H O : 1167.0 [M]. Found: 1190.0 [MꢁNa ].
/
4
3
74 36
(
6
/
6
Acknowledgements
2
/
(
(
(
/
1220;
This work was supported by The Chinese Academy of
Sciences (KZCX3-J-08) and by The National Natural
Science Foundation of China (Projects 30070185 and
/
1
/
3
9970864).
(
1
/
7
. (a) J. Ning; W. Zhang; Y. Yi; G. Yang; Z. Wu; J. Yi; F.
Kong, Bioorg. Med. Chem., 2003, in press.;
References
(
b) Ning, J.; Yi, Y.; Kong, F. Tetrahedron Lett. 2002,
5545ꢀ5549.
8. Zhang, J.; Kong, F. Tetrahedron Lett. 2003, 1839ꢀ
1
.
Essentials of Glycobiology; Varki, A.; Cummings, R.;
Esko, J.; Freeze, H.; Hart, G.; Marth, J., Eds.; Cold
Spring Harbor Laboratory: Cold Spring Harbor, New
York, 1999.
/
/
1842.
9. Copeland, C.; Stick, R. V. Aust. J. Chem. 1978, 31,
1371.
10. Schmidt, R. R.; Kinzy, W. Adv. Carbohydr. Chem.
2
. Dwek, R. A. Chem. Rev. 1996, 96, 683ꢀ
. Grice, P.; Ley, S. V.; Pietruszka, J.; Priepke, H. W. M.
Angew. Chem., Int. Ed. Engl. 1996, 35, 197ꢀ200.
/720.
3
/
Biochem. 1994, 50, 21ꢀ
11. Zhu, Y.; Kong, F. Synlett 2000, 1783ꢀ
12. (a) Zhu, Y.; Kong, F. Synlett 2000, 663ꢀ
(b) Zhu, Y.; Kong, F. Carbohydr. Res. 2001, 332, 1ꢀ21.
/125.
4
. Wyss, D. F.; Choi, J. S.; Li, J.; Knoppers, M. H.; Willis,
K. J.; Arulanandam, A. R. N.; Smolyar, A; Reinherz, E.
/1787.
/667;
L.; Wagner, G. Science 1995, 269, 1273ꢀ
/1298.
/