Synthesis of a model compound related to an anti-ulcer pectic polysaccharide

Article abstract of DOI:10.1016/S0008-6215(99)00315-8

A stereocontrolled synthesis of the model compound for an anti-ulcer active polysaccharide (Bupleuran 2IIc) is described. Glycosidation of the disaccharide acceptor, 2-O-acetyl-3-O-benzyl-4-O-(p-methoxybenzyl)-α-L-rhamnopyranosyl-(1→4)-2,3,6-tri-O-benzyl-α-D-galactopyranosyl trichloroacetimidate, with the disaccharide receptor, allyl 3,4-di-O-benzyl-α-L-rhamnopyranosyl-(1→4)-2,3,6-tri-O-benzyl-β-D-galactopyranoside, using silver triflate (AgOTf) as a promoter gave the desired tetrasaccharide derivative, which was transformed into the acidic tetrasaccharide, corresponding to a segment of the rhamnogalacturonan (Bupleuran 2IIc) polysaccharide, propyl α-L-Rha-(1→4)-α-D-GalA-(1→2)-α-L-Rha-(1→4)-β-D-GalA, via removal of the corresponding ether and ester protecting groups, followed by oxidation. Copyright (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0008-6215(99)00315-8

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Carbohydrate Research 325 (2000) 83–92
Synthesis of a model compound related to an anti-ulcer
pectic polysaccharide
Michiko Maruyama a, Tadahiro Takeda a,*, Noriko Shimizu a, Noriyasu Hada a,
Haruki Yamada b
a Kyoritsu College of Pharmacy, Shibakoen 1-5-30, Minato-ku, Tokyo 105-8512, Japan
b Oriental Medicine Research Center of Kitasato Institute, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8642, Japan
Received 29 September 1999; accepted 22 November 1999
Abstract
A stereocontrolled synthesis of the model compound for an anti-ulcer active polysaccharide (Bupleuran 2IIc) is
described. Glycosidation of the disaccharide acceptor, 2-O-acetyl-3-O-benzyl-4-O-(p-methoxybenzyl)-a-
pyranosyl-(1“4)-2,3,6-tri-O-benzyl-a- -galactopyranosyl trichloroacetimidate, with the disaccharide receptor, allyl
3,4-di-O-benzyl-a- -rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-b- -galactopyranoside, using silver triflate (AgOTf)
as a promoter gave the desired tetrasaccharide derivative, which was transformed into the acidic tetrasaccharide,
corresponding to a segment of the rhamnogalacturonan (Bupleuran 2IIc) polysaccharide, propyl a- -Rha-(1“4)-a-
-GalA, via removal of the corresponding ether and ester protecting groups,
L-rhamno-
D
L
D
L
D
-GalA-(1“2)-a-
L
-Rha-(1“4)-b-
D
followed by oxidation. © 2000 Elsevier Science Ltd. All rights reserved.
Keywords: Acidic tetrasaccharide; Anti-ulcer pectic polysaccharide; Bupleurum falcatum; Chemical synthesis
Bupleuran 2IIc has a molecular weight of
63,000 and contains 93.6% galacturonic acid,
with small amounts of neutral sugars such as
rhamnose, arabinose, galactose, glucose, man-
nose and xylose. It has been characterized as a
pectin, consisting of 85.8% of a polygalacturo-
nan region, which is made up of mainly a-
(1“4)-linked galacturonic acid with small
amounts of 2,4- and 3,4-di-O-substituted
galacturonic acid, and an 8.6% ramified re-
gion. The ramified region contains several
short, neutral carbohydrate chains and a b-
(1“6)-galactan chain attached to position-4
of either the 2-linked rhamnosyl residue
through 4-linked galacturonic acid, or a 2-
linked rhamnose linked directly to the rham-
nogalacturonan core. The structure of the
pectic polysaccharide consists of ‘ramified’
(rhamnogalacturonan with neutral side chains,
1. Introduction
Yamada et al. [1] have reported that during
a study of the polysaccharide components of
Chinese herbs, the potent anti-ulcer polysac-
charide (Bupleuran 2IIc) against HCl–ethanol
induced ulcerogenesis in mice was obtained
from a hot-water extract of the roots of Bu-
pleurum falcatum L. (Japanese name, Saiko),
which has been used in Chinese and Japanese
herbal medicine for the treatment of chronic
hepatitis, nephrosis syndrome and autoim-
mune diseases [2]. Bupleuran 2IIc showed
higher activity than using a clinical anti-ulcer
drug, Sucralfate [3], at the same dose.
* Corresponding author. Tel.: +81-3-54002696; fax: +81-
3-54002556.
E-mail address: takeda-td@kyoritsu-ph.ac.jp (T. Takeda)
0008-6215/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(99)00315-8

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M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
PG-1) and Kdo-containing (1“4)-a-
turonan regions (PG-2) [4]. The backbone of
PG-1 is composed of an a- -Rha-(1“4)-a-
GalA-(l“2)-repeating unit. The repeating
unit of PG-1 was the target for the synthetic
studies as part of our investigations on the
synthesis of oligosaccharides of biological
interest.
D
-galac-
signals for H-1 and H-1% being observed at l
4.40 (J 7.9 Hz) and 5.20 (J 1.8 Hz), respec-
tively. In the 13C NMR spectrum (Table 1),
the CH coupling of the signal of C-1 (99.0
ppm) was 178 Hz, as determined in an INEPT
experiment, so the newly formed glycosidic
bond is linked in the a configuration. A het-
eronuclear multiple bond correlation (HMBC)
experiment showed a correlation between H-1%
(5.20 ppm) and the C-4 carbon (73.6 ppm).
Removal of the acetyl groups of 3 with
NaOMe in MeOH gave the disaccharide (4,
70%) with the 2%,3%,4%-positions free. Isopropyl-
idenation of 4 with 2,2-dimethoxypropane in
the presence of p-TsOH gave compound 5
(93%), which was selectively mono-O-(p-
methoxybenzyl)ated and/or mono-O-benzyl-
ated with p-methoxybenzyl chloride and/or
benzyl bromide in the presence of NaH in
N,N-dimethylformamide to afford the com-
pound 6 (65%) and/or 7 (82%). Compounds 6
and/or 7 were converted into the 3%-O-(p-
methoxybenzyl)ated and/or 3%-O-benzylated
disaccharide acceptor 10 or 11 by acid-cata-
lyzed O-deisopropylidenation, followed by se-
lective benzylation using n-Bu2SnO, BnBr and
n-Bu4NBr in benzene [7]. These compounds
were used partly as acceptors.
Meanwhile, compounds 10 and 11 were
acetylated with acetic anhydride to give com-
pounds 12 and 13. Donors 14 and 15 were
prepared from 12 and 13 by deallylation with
palladium chloride in 90% acetic acid contain-
ing sodium acetate, followed by treatment of
the resulting hemiacetal with trichloroacetoni-
trile and DBU in dichloromethane [8] (Scheme
1).
The coupling of 11 and 14 in the presence
of AgOTf gave the expected product 16 (49%
yield). Similarly, the reaction of 10 with the
acceptor disaccharide 15 gave tetrasaccharide
17 (67% yield).
L
D
-
The tetrasaccharide derivative, a-
(1“4)-a- -Gal-(1“2)-a- -Rha-(1“4)-b-
Gal (20) was obtained by condensation of
allyl 3,4-di-O-benzyl-a- -rhamnopyranosyl-
(1“4)-2,3,6-tri-O-benzyl-b- -galactopyran-
oside (11) with 2-O-acetyl-3-O-benzyl-4-O-(p-
methoxybenzyl)-a- -rhamnopyranosyl-(1“4)-
2,3,6-tri-O-benzyl-a- -galactopyranosyl tri-
L
-Rha-
D
L
D-
L
D
L
D
chloroacetimidate (14) in the presence of silver
triflate (AgOTf) to give the tetrasaccharide
derivative (16). Deacetylation of compound
16, followed by debenzylation and oxidation,
gave the dicarboxylic acid tetrasaccharide,
propyl a-
L
-Rha-(1“4)-a-
D
-GalA-(1“2)-a- -
L
Rha-(1“4)-b-
D
-GalA (21).
2. Results and discussion
We now describe the synthesis of this re-
peating acidic tetrasaccharide, the propyl gly-
coside, a-
L
-Rha-(1“4)-a-
D
-GalA-(1“2)-a-
L
-
Rha-(1“4)-b-
D
-GalA (21), as a model com-
pound. In the course of its synthesis, it is
difficult to synthesize a galacturonic acid with
the 4-position free as a starting material, so we
used
D-galactose instead of the -galacturonic
D
acid. Synthesis of the neutral tetrasaccharide
derivative (16) was carried out by the coupling
of the allyl diglycoside acceptor (11), having
the 4-position free, and the non-reducing end
disaccharide imidate (14).
Allyl 2,3,4-tri-O-acetyl-a-
osyl-(1“4)-2,3,6-tri-O-benzyl-b-
pyranoside (3) was prepared in 97% yield by
using allyl 2,3,6-tri-O-benzyl-b- -galactopyr-
anoside (1) [5] as a galactosyl acceptor and the
L
-rhamnopyran-
D
-galacto-
Recently, Reimer and co-workers have syn-
thesized a hydroxyl-protected tetrasaccharide
intermediate corresponding to a segment of
the rhamnogalacturonan I polysaccharide,
using the glycosyl trichloroacetimidate tech-
nique [9].
D
readily available 2,3,4 - tri - O - acetyl - a - -
L
rhamnopyranosyl trichloroacetimidate (2) [6]
as a rhamnosyl donor in the presence of
AgOTf as a promotor in dichloromethane.
The anomeric configuration of compound 3
The structural assignment of these products
1
was based on the comparison of their H and
1
was confirmed by H NMR spectroscopy, the
13C NMR data. The presence of a characteris-

M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
85
Table 1
13C NMR data (l) for compounds 3–12
Carbon atom
Compound
3
4
5
6
7
8
9
10
11
12
C-1
C-2
C-3
C-4
C-5
C-6
C-1%
(JC-1%, H-1%
C-2%
C-3%
C-4%
C-5%
C-6%
ꢀCHꢁ
CH2 (All)
CH2Ph
103.0
79.3
81.4
73.6
72.9
69.0
99.0
(178 Hz)
69.8
69.2
71.1
67.0
17.5
134.0
70.5
75.5
73.6
73.3
72.9
103.0
79.2
81.8
71.8
73.5
69.1
100.9
103.0
79.1
81.7
71.7
73.4
69.3
98.1
103.0
79.1
81.8
71.3
73.5
69.3
97.9
103.0
79.0
81.8
71.3
71.3
69.3
97.9
102.9
79.2
81.8
72.4
71.2
69.1
100.6
103.0
79.2
81.8
72.3
73.2
69.1
100.7
102.9
79.1
81.7
72.4
73.5
69.1
100.5
103.0
79.2
81.8
72.5
73.4
69.2
100.5
103.0
79.0
81.5
72.4
73.1
67.0
99.1
)
71.0
71.5
72.9
69.0
17.7
133.8
70.6
75.3
73.4
73.0
73.3
76.0
78.3
74.6
66.1
17.2
134.0
70.5
75.1
73.6
73.0
72.7
76.2
78.4
80.6
65.2
17.8
134.0
70.5
75.2
73.6
73.0
72.7
76.2
78.3
80.9
65.2
17.8
134.0
70.4
75.1
73.5
73.0
71.1
71.2
81.1
68.0
18.1
134.0
70.4
75.3
74.3
73.6
73.3
71.1
71.2
81.5
68.0
18.1
134.0
70.4
75.3
74.6
73.6
68.6
79.5
79.7
68.1
18.0
134.0
70.3
75.1
74.7
73.3
73.1
72.0
69.7
79.7
79.9
68.1
18.0
134.1
70.5
75.2
75.1
73.6
73.2
72.1
68.9
78.0
79.5
68.4
18.1
134.0
70.4
75.1
74.9
73.5
73.2
71.7
21.1
CH3(Ac)
20.89
20.84
20.76
170.1
169.8
169.6
CꢁO(Ac)
169.8
C(CH3)2
C(CH3)
109.1
28.1
26.3
108.8
28.1
26.4
55.3
108.8
28.0
26.4
CH3O
55.3
55.1
55.3
Scheme 1.

86
M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
Scheme 2.
tic signal for p-methoxybenzyl and one acetyl
were established by 1H, 13C NMR spec-
troscopy and MALDI-TOFMS spectrometry.
1
group in the H NMR spectra of 16 and 17
demonstrated that they resembled tetrasaccha-
ride derivatives. The 13C NMR spectrum of 16
contained signals for anomeric carbons at
103.0 (157 Hz, C-1a), 99.0 (174 Hz, C-1d),
97.9 (170 Hz, C-1b), and 95.5 ppm (168 Hz,
C-1c), which indicated the newly formed gly-
cosidic linkage at C-1c to be of the a
configuration.
Deacetylation of 16 with methanolic sodium
methoxide gave 18 (93%). Debenzylation with
PdꢀC then gave the propyl tetrasaccharide
compound 20. During the deallylation of the
allyl glycoside 18, oxidation of the allyl to the
2-oxopropyl group was encountered. Oxida-
tion of 20 to the uronic acid 21 was carried
out with 2,2,6,6-tetramethylpiperidine 1-oxide
(TEMPO), KBr and NaOCl in aqueous
3. Experimental
General.—Optical rotations were deter-
mined with a Jasco DIP-140 digital polarime-
1
ter. H and 13C NMR spectra were recorded
with a Jeol JNM A500 FT NMR spectrome-
ter. Tetramethylsilane was the internal stan-
dard for solutions in CDCl3 and/or CD3OD,
and sodium 4,4-dimethyl-4-silapentane-1-sul-
fonate (DDS) for solutions in D2O. TOF-
MAS was recorded on a perceptive voyager
RP mass spectrometer. Thin-layer chromatog-
raphy (TLC) was performed on Silica Gel 60
F254 (E. Merck) with detection by quenching
of UV fluorescence (254 nm) and by spraying
with a 10% H2SO4 solution. Column chro-
matography was carried out on Silica Gel 60
sodium
hydrogencarbonate
(50%)
[10]
(Scheme 2). The structure and purity of 21

M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
87
(E. Merck) or IATROBEADS 6RS-8060.
High-performance liquid chromatography
(HPLC) was carried out using a Shimadzu
SCL-10 A with a Shimadzu SPD-10 A detec-
tor. HPLC conditions: column, CAPCELL
PAK C18: UG80A 5 mm; solvent, H2O, 9
mL/min; detector, UV (210 nm). Allyl 2,3,6-
then neutralized with Amberlite IR-120B
(H+), filtered, and concentrated. The residue
was chromatographed on silica gel using 50:1
CHCl3–MeOH as eluent to give 4 (6.02 g,
70%); Rf 0.36 (10:1 CHCl3–MeOH), [h]D23
−1.94° (c 2.4, CHCl3); 1H NMR data
(CD3OD): l 7.36–7.22 (m, 15 H, aromatic),
5.97–5.91 (m, 1 H, ꢀCHꢁCH2), 5.34–5.15 (m,
2 H, CH2ꢁ), 5.28 (d, 1 H, J1%,2% 1.8 Hz, H-1%),
4.85–4.43 (m, 6 H, 3×ꢀCH2Ph), 4.43 (d, 1 H,
J1,2 7.3 Hz, H-1), 4.38–4.12 (m, 2 H, ꢀCH2-
CHꢁCH2), 4.15 (bd, 1 H, J4,5 2.4 Hz, H-4),
3.99 (dd, 1 H, J2%,3% 3.7 Hz, H-2%), 3.73 (dd, 1
H, J3%,4% 9.8 Hz, H-3%), 3.69 (m, 1 H, J5%,6% 6.1
Hz, H-5%), 3.66 (m, 2 H, H-6), 3.65 (m, 1 H,
J5,6 6.1 Hz, H-5), 3.61 (dd, 1 H, J2,3 9.8 Hz,
H-2), 3.41 (t, 1 H, J4%,5% 9.2 Hz, H-4%), 1.21 (d,
3 H, H-6%) Anal. Calcd for C36H44O10: C,
67.91; H, 6.96. Found: C, 67.78; H, 6.88.
tri-O-benzyl-b-D-galactopyranoside (1) and
2,3,4-tri-O-acetyl-a-
L
-rhamnopyranosyl tri-
chloroacetimidate (2) were prepared by litera-
ture methods [5,6].
Allyl 2,3,4-tri-O-acetyl-h-
L
-rhamnopyran-
-galacto-
pyranoside (3).—A mixture of allyl 2,3,6-tri-
O-benzyl-b- -galactopyranoside (1) (1.08 g,
2.2 mmol), 2,3,4-tri-O-acetyl-a- -rhamnopyr-
osyl-(1“4)-2,3, 6-tri-O-benzyl-i-
D
D
L
anosyl trichloroacetimidate (2, 1.80 g, 4.4
,
mmol), and 4 A MS (400 mg) in dry CH2Cl2
(22 mL) was stirred for 1 h under argon and
then at room temperature (rt) in the dark.
Silver triflate (87.8 mg, 0.36 mmol) was added
to the mixture. After 24 h CHCl3 was added,
the mixture was filtered through a pad of
Celite, diluted with CHCl3, and successively
washed with water and satd aq NaHCO3,
dried over Na2SO4, filtered, and concentrated.
The residue was purified by column chro-
matography using 50:1 benzene–acetone as
eluent to provide 3 (1.63 g, 97%); Rf 0.64 (8:1
benzene–acetone); [h]2D2 −26.2° (c 4, CHCl3);
1H NMR data (CDCl3): l 7.37–7.25 (m, 15 H,
aromatic), 5.98–5.92 (m, 1 H, ꢀCHꢁCH2),
5.50 (dd, 1 H, J2%,3% 3.1 Hz, H-2%), 5.35 (dd, 1
H, J3%,4% 9.8 Hz, H-3%), 5.34–5.20 (m, 2 H,
CH2ꢁ), 5.20 (d, 1 H, J1%,2% 1.8 Hz, H-1%), 5.03 (t,
1 H, J4%,5% 9.8 Hz, H-4%), 4.95–4.52 (m, 6 H,
3×ꢀCH2Ph), 4.40 (d, 1 H, J1,2 7.9 Hz, H-1),
4.44–4.15 (m, 2 H, ꢀCH2CHꢁCH2), 4.09 (bd,
1 H, H-4), 4.00 (m, 1 H, J5%,6% 6.1 Hz, H-5%),
3.79 (dd, 1 H, J2,3 9.8 Hz, H-2), 3.72 (dd, 1 H,
Jgem 9.2 Hz, H-6a), 3.67 (dd, 1 H, H-6b), 3.59
(t, 1 H, J5,6 6.4 Hz, H-5), 3.49 (dd, 1 H, J3,4
2.4 Hz, H-3), 2.04, 2.04, 1.97 (each s, 9 H,
3×ꢀCH3), 1.14 (d, 3 H, H-6%). Anal. Calcd
for C42H50O13: C, 66.13; H, 6.61. Found: C,
66.02; H, 6.58.
Allyl 2,3-O-isopropylidene-h-
L
-rhamnopyr-
-galacto-
anosyl-(1“4)-2,3,6-tri-O-benzyl-i-
D
pyranoside (5).—To a solution of compound 4
(3.91 g, 6.1 mmol) in 2,2-dimethoxypropane
(70 mL) was added p-TsOH (103 mg). The
mixture was stirred at rt for 24 h, then neu-
tralized with triethylamine and evaporated to
give 5 (3.85 g, 93%); Rf 0.79 (10:1 CHCl3–
MeOH); [h]2D0 −1.06 (c 4.8 CHCl3); H NMR
1
data (CDCl3): l 7.34–7.24 (m, 15 H, aro-
matic), 5.99–15.92 (m, 1 H, ꢀCHꢁCH2), 5.58
(bs, 1 H, H-1%), 5.27 (dd, 2 H, CH2ꢁ), 4.92–
4.52 (m, 6 H, 3×ꢀCH2Ph), 4.42 (d, 1 H, J1,2
7.3 Hz, H-1), 4.30 (bd, 1 H, J2%,3% 6 1 Hz, H-2%),
4.16 (d, 1 H, J4,5 2.4 Hz, H-4), 4.46–4.12 (m,
2 H, ꢀCH2CHꢁCH2), 4.05 (t, 1 H, J3%,4% 6.7 Hz,
H-3%), 3.72 (dd, 1 H, J2,3 2.4 Hz, H-4), 3.66 (m,
2 H, H-6), 3.66 (m, 1 H, J5%,6% 6.1 Hz, H-5%),
3.58 (t, 1 H, J5,6 5.8 Hz, H-5), 3.50 (dd, 1 H,
J3,4 2.4 Hz, H-3), 3.36 (m, 1 H, H-4%), 2.54 (d,
1 H, OH), 1.52, 1.32 (each s, 6 H, 2×ꢀCH3),
1.21 (d, 3 H, H-6%). Anal. Calcd for C39H48O10:
C, 69.21; H, 7.15. Found: C, 69.08; H, 7.09.
Allyl 2,3-O-isopropylidene-4-O-(p-methoxy-
benzyl)-h-
L
-rhamnopyranosyl-(1“4)-2,3,6-tri-
-galactopyranoside (6).—To a
O-benzyl-i-
D
solution of 5 (6.40 g, 9.46 mmol) in DMF (98
mL) was added NaH (1.58 g, 50% in mineral
oil). The mixture was stirred for 1 h and then
cooled to 0 °C, and p-methoxybenzyl chloride
(1.96 mL) was added dropwise. The mixture
was left at rt under vacuum for 1 h, then at
Allyl h-
L
-rhamnopyranosyl-(1“4)-2,3,6-tri-
-galactopyranoside (4).—To a
O-benzyl-i-
D
solution of compound 3 (10.3 g, 13.5 mmol) in
MeOH (108 mL) was added NaOMe (215
mg). The mixture was stirred at rt for 24 h,

88
M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
atmospheric pressure overnight. Excess NaH
was destroyed by addition of MeOH. The
mixture was partitioned between CHCl3 and
water, the aq phase was extracted with CHCl3,
and the combined organic phases were washed
with water, dried (Na2SO4), filtered, and con-
centrated. The residue was chromatographed
on silica gel using 10:1 hexane–EtOAc as
eluent to provide 6 (4.69 g, 65%); Rf 0.68 (8:1
J5,6 5.8 Hz, H-5), 3.50 (dd, 1 H, J3,4 2.4 Hz,
H-3), 3.21 (dd, 1 H, J4%,5% 7.3 Hz, H-4%), 1.49,
1.34 (each s, 6 H, 2×ꢀCH3), 1.20 (d, 3 H,
H-6%). Anal. Calcd for C46H54O10: C, 72.04; H,
7.10. Found: C, 71.08; H, 7.03.
Allyl 4-O-(p-methoxybenzyl)-h-
L
-rhamno-
pyranosyl - (1“4) - 2,3,6 - tri - O - benzyl - i -
D
-
galactopyranoside (8).—A solution of com-
pound 6 (4.69 g, 6.12 mmol) in 80% aq AcOH
was stirred for 2.5 h at 50 °C. The resultant
solution was concentrated and chromato-
graphed on silica gel with 50:1 CHCl3–MeOH
as eluent to provide 8 (3.19 g, 67%); Rf 0.27
(8:1 benzene–acetone); 1H NMR data
(CDCl3): l 7.35–7.24 (m, 19 H, aromatic),
5.94 (m, 1 H, ꢀCHꢁCH2), 5.24 (d, 1 H, J1%,2%
1.8 Hz, H-1%), 4.91–4.49 (m, 8 H, 4×
ꢀCH2Ph), 4.39 (d, 1 H, J1%,2% 7.3 Hz, H-1),
4.42–4.12 (m, 2 H, ꢀCH2CHꢁCH2), 4.10 (d, 1
H, J4,5 3.1 Hz, H-4), 4.04 (d, 1 H, J2%,3% 3.7 Hz,
H-2%), 3.94 (dd, 1 H, J3%,4% 8.6 Hz, H-3%), 3.79
(m, 1 H, J5%,6% 6.1 Hz, H-5%), 3.77 (s, 3 H,
OCH3), 3.69 (dd, 1 H, J2,3 9.8 Hz, H-2), 3.67
(m, 2 H, H-6), 3.55 (t, 1 H, J5,6 6.1 Hz, H-5),
3.48 (dd, 1 H, J3,4 2.4 Hz, H-3), 3.31 (t, 1 H,
J4%,5% 8.9 Hz, H-4%), 2.45, 2.38 (each d, 2 H,
2×OH), 1.24 (d, 3 H, H-6%). Anal. Calcd for
C44H52O11: C, 70.58; H, 5.92. Found: C, 69.28;
H, 5.81.
1
benzene–acetone); H NMR data (CDCl3): l
7.36–7.26 (m, 19 H, aromatic), 5.95 (m, 1 H,
ꢀCHꢁCH2), 5.60 (bs, 1 H, H-1%), 5.35–5.18
(m, 2 H, ꢁCH2), 4.92–4.49 (m, 8 H, 4×
ꢀCH2Ph), 4.40 (d, 1 H, J1,2 7.9 Hz, H-1),
4.46–4.10 (m, 2 H, ꢀCH2CHꢁCH2), 4.29 (d, 1
H, J2%,3% 7.3 Hz, H-2%), 4.24 (t, 1 H, J3%,4% 9.8 Hz,
H-3%), 4.15 (bd, 1 H, J4,5 1.4 Hz, H-4), 3.79 (m,
1 H, J5%,6% 6.1 Hz, H-5%), 3.74 (dd, 1 H, J2,3 9.8
Hz, H-2), 3.64 (dd, 2 H, H-6), 3.56 (t, 1 H, J5,6
6.1 Hz, H-5), 3.51 (dd, 1 H, J3,4 3.1 Hz, H-3),
3.18 (dd, 1 H, J4%,5% 7.3 Hz, H-4%), 3.81 (s, 3 H,
OCH3), 1.50, 1.33 (each s, 6 H, 2×ꢀCH3),
1.18 (d, 3 H, H-6%). Anal. Calcd for C47H56O11:
C, 70.83; H, 7.08. Found: C, 70.69; H, 6.93.
Allyl 4-O-benzyl-2,3-O-isopropylidene-h-
rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-
i- -galactopyranoside (7).—To a solution of
L
-
D
5 (3.21 g, 4.74 mmol) in DMF (54 mL) was
added NaH (790 mg, 50% in mineral oil). The
mixture was stirred for 30 min and then
cooled to 0 °C, and benzyl bromide (1.07 mL)
was added dropwise. The mixture was left at
rt under vacuum for 1 h, then at atmospheric
pressure overnight. Excess NaH was destroyed
by addition of MeOH. The mixture was parti-
tioned between CHCl3 and water, the aq
phase was extracted with CHCl3, and the
combined organic phases were washed with
water, dried (Na2SO4), filtered, and concen-
trated. The residue was chromatographed on
silica gel using 10:1 hexane–EtOAc as eluent
to provide 7 (3.00 g, 82%); Rf 0.77 (8:1 ben-
zene–acetone); 1H NMR data (CDCl3): l
7.37–7.21 (m, 20 H, aromatic), 5.99–5.91 (m,
1 H, ꢀCHꢁCH2), 5.60 (bs, 1 H, H-1%), 5.35–
5.17 (m, 2 H, CH2ꢁ), 4.93–4.50 (m, 8 H,
4×ꢀCH2Ph), 4.41 (d, 1 H, J1,2 7.9 Hz, H-1),
4.45–4.08 (m, 2 H, ꢀCH2CHꢁCH2), 4.30 (bd,
1 H, J2%,3% 5.5 Hz, H-2%), 4.26 (t, 1 H, J3%,4% 6.4
Hz, H-3%), 4.16 (d, 1 H, J4,5 3.1 Hz, H-4), 3.74
(dd, 1 H, J2,3 7.9 Hz, H-2), 3.72 (t, 2 H, H-6),
3.68 (dd, 1 H, J5%,6% 6.1 Hz, H-5%), 3.57 (t, 1 H,
Allyl 4 - O - benzyl - h -
L
- rhamnopyranosyl-
-galactopyran-
(1“4)-2,3,6-tri-O-benzyl-i-
D
oside (9).—A solution of compound 7 (3.00 g,
3.91 mmol) in 80% aq AcOH was stirred for
2.5 h at 50 °C. The resultant solution was
concentrated to dryness, and the residue was
chromatographed on silica gel using 50:1
CHCl3–MeOH as eluent to provide 9 (2.67 g,
94%); Rf 0.17 (8:1 benzene–acetone); 1H
NMR data (CDCl3): l 7.34–7.21 (m, 20 H,
aromatic), 5.98–5.90 (m, 1 H, ꢀCHꢁCH2),
5.34–5.17 (m, 2 H, CH2ꢁ), 5.25 (d, 1 H, J1%,2%
1.8 Hz, H-1%), 4.91–4.49 (m, 8 H, 4×
ꢀCH2Ph), 4.46–4.13 (m, 2 H, ꢀCH2CHꢁCH2),
4.39 (d, 1 H, J1,2 7 9 Hz, H-1), 4.10 (d, 1 H,
J4,5 3.1 Hz, H-4), 4.04 (bd, 1 H, H-2%), 3.97 (m,
1 H, H-3%), 3.80 (dd, 1 H, J5%,6% 6.4 Hz, H-5%),
3.68 (dd, 1 H, J2,3 8.9 Hz, H-2), 3.63 (d, 2 H,
H-6), 3.56 (t, 1 H, J5,6 6.1 Hz, H-5), 3.48 (dd,
1 H, J3,4 3.1 Hz, H-3), 3.34 (t, 1 H, J4%,5% 9.2
Hz, H-4%), 2.45 (each d, 2 H, 2×OH), 1.25 (d,
3 H, H-6%). Anal. Calcd for C43H50O10: C,
71.06; H, 6.93. Found: C, 69.93; H, 6.81.

M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
89
(CDCl3): l 7.37–7.24 (m, 25 H, aromatic),
6.00–5.92 (m, 1 H, ꢀCHꢁCH2), 5.34 (bs, 1 H,
H-1%), 5.22–5.20 (m, 2 H, CH2ꢁ), 4.91–4.49
(m, 10 H, 5×ꢀCH2Ph), 4.44–4.13 (m, 2 H,
ꢀCH2CHꢁCH2), 4.39 (d, 1 H, J1,2 7.9 Hz,
H-1), 4.19 (dd, 1 H, J2%,3% 1.5 Hz, H-2%), 4.11 (d,
1 H, J4,5 3.1 Hz, H-4), 3.88 (dd, 1 H, J3%,4% 3.3
Hz, H-3%), 3.81 (dd, 1 H, J5%,6% 7.9 Hz, H-5%),
3.71–3.63 (m, 2 H, H-6), 3.64 (d, 1 H, J2,3 2.5
Hz, H-2), 3.56 (t, 1 H, J5,6 6.1 Hz, H-5), 3.49
(dd, 1 H, J3,4 3.1 Hz, H-3), 3.45 (t, 1 H, J4%,5%
9.2 Hz, H-4%), 2.40 (s, 1 H, OH), 1.23 (d, 3 H,
H-6%). Anal. Calcd for C50H56O10: C, 73.51; H,
6.91. Found: C, 72.92; H, 6.82.
Allyl 3-O-benzyl-4-O-(p-methoxybenzyl)-h-
-rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-
L
i- -galactopyranoside (10).—A mixture of
D
compound 8 (3.19 g, 4.20 mmol), dibutyltin
oxide (1.3 g), and dry benzene (52 mL) was
stirred under reflux, using a calcium chloride
drying tube, for 5 h. Benzene (26 mL) was
distilled off, and the solution was cooled to
50 °C and treated with tetrabutylammonium
bromide (1.5 g) and benzyl bromide (0.62
mL). After the mixture was stirred for 3 h at
50 °C, the solution was concentrated. The
residue was stirred with EtOAc (52 mL) at
0 °C for 12 h. The solids were removed by
filtration and the filtrate was concentrated.
Purification of the residue by chromatography
with 70:1 benzene–acetone as eluent provided
10 (3.30 g, 93%); Rf 0.51 (8:1 benzene–ace-
Allyl 2 - O - acetyl - 3 - O - benzyl - 4 - O - (p-
methoxybenzyl)-h-
L
-rhamnopyranosyl-(1“4)-
-galactopyranoside (12).
2,3,6-tri-O-benzyl-i-
D
—To a solution of compound 10 (628 mg,
0.47 mmol) in pyridine (10 mL) was added
Ac2O (10 mL) at 0 °C over a period of 2 h.
The resultant solution was poured into ice-
water and extracted with CHCl3. The organic
phase washed with water, 5% HCl, and satd
aq NaHCO3, dried over Na2SO4, filtered and
concentrated.
1
tone); H NMR data (CDCl3): l 7.36–7.12
(m, 24 H, aromatic), 5.95 (m, 1 H,
ꢀCHꢁCH2), 5.34 (bs, 1 H, H-1%), 5.40–5.12
(m, 2 H, CH2ꢁ), 4.97–4.47 (m, 10 H, 5×
ꢀCH2Ph), 4.40 (d, 1 H, J1,2 7.3 Hz, H-1),
4.43–4.03 (m, 2 H, ꢀCH2CHꢁCH2), 4.18 (bd,
1 H, J2%,3% 3.1 Hz, H-2%), 4.09 (bs, 1 H, H-4),
3.96 (dd, 1 H, J3%,4% 9.2 Hz, H-3%), 3.83–3.78
(m, 1 H, J5%,6% 6.1 Hz, H-5%), 3.72 (s, 3 H,
OCH3), 3.70–3.67 (m, 2 H, H-6), 3.64 (dd, 1
H, J2,3 9.2 Hz, H-2), 3.55 (t, 1 H, J5,6 6.7 Hz,
H-5), 3.46 (t, 1 H, J4%,5% 9.2 Hz, H-4%), 3.46 (t,
1 H, J3,4 9.2 Hz, H-3), 2.54 (d, 1 H, OH), 1.23
(d, 3 H, H-6%). Anal. Calcd for C51H58O11: C,
72.32; H, 6.90. Found: C, 72.46; H, 6.78.
The residue was purified by column chro-
matography using 100:1 benzene–acetone as
eluent to provide 12 (466 mg, 71%); Rf 0.70
(8:1 benzene–acetone); 1H NMR data
(CDCl3): l 7.37–6.84 (m, 24 H, aromatic),
5.99–5.91 (m, 1 H, ꢀCHꢁCH2), 5.59 (dd, 1 H,
J2%,3% 3.1 Hz, H-2%), 5.36–5.18 (m, 1 H, CH2ꢁ),
5.23 (d, 1 H, J1%,2% 1.8 Hz, H-1%), 4.93–4.45 (m,
10 H, 5×ꢀCH2Ph), 4.43–4.11 (m, 2 H,
ꢀCH2CHꢁCH2), 4.10 (bd, 1 H, H-4), 3.94 (dd,
1 H, J3%,4% 9.2 Hz, H-3%), 3.83 (m, 1 H, J5%,6% 6.1
Hz, H-5%), 3.79 (s, 3 H, OCH3), 3.70 (dd, 1 H,
J2,3 9.8 Hz, H-2), 3.65 (m, 2 H, H-6), 3.55 (t,
1 H, J5,6 6.4 Hz, H-5), 3.48 (dd, 1 H, J3,4 3.1
Hz, H-3), 3.37 (t, 1 H, J4%,5% 9.8 Hz, H-4%), 2.06
(s, 3 H, CH3), 1.23 (d, 3 H, H-6). Anal. Calcd
for C53H60O12: C, 71.60; H, 6.80. Found: C,
70.92; H 6.68.
Allyl 3,4-di-O-benzyl-h-
L
-rhamnopyranosyl-
-galactopyran-
(1“4)-2,3,6-tri-O-benzyl-i-
D
oside (11).—A mixture of compound 9 (2.57
g, 3.54 mmol), dibutyltin oxide (1.1 g), and
dry benzene (17.2 mL) was stirred under
reflux, using calcium chloride drying tube, for
5 h. Benzene (8 mL) was distilled off, and the
solution was cooled to 50 °C and treated with
tetrabutylammonium bromide (1.26 g) and
benzyl bromide (0.55 mL). After the mixture
was stirred for 3 h at 50 °C, the solution was
concentrated. The residue was stirred with
EtOAc (52 mL) at 0 °C for 12 h. The solids
were removed by filtration and the filtrate was
concentrated. Purification of the residue by
chromatography with 70:1 benzene–acetone
as eluent provided 11 (2.62 g, 91%); Rf 0.49
(8:1 benzene–acetone); 1H NMR data
Allyl 2 - O - acetyl - 3,4 - di - O - benzyl - h -
rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-i-
-galactopyranoside (13).—To a solution of
L
-
D
compound 11 (2.62 g, 3.21 mmol) in pyridine
(10 mL) was added Ac2O (10 mL) at 0 °C for
12 h. The resultant solution was poured into
ice-water and extracted with CHCl3. The or-
ganic phase washed with water, 5% HCl and

90
M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
rial was filtered off, the filtrate was concen-
trated, and the residue was extracted with
EtOAc. The extract was washed with water,
satd aq NaHCO3, and satd NaCl, dried
(Na2SO4), and concentrated. The residue was
chromatographed on silica gel using 30:1 ben-
zene–acetone as eluent to give 2-O-acetyl-3,4-
satd aq NaHCO3, dried over Na2SO4, filtered
and concentrated. The residue was purified by
column chromatography using 100:1 ben-
zene–acetone as eluent to provide 13 (2.73 g,
99%); Rf 0.71 (8:1 benzene–acetone); 1H
NMR data (CDCl3): l 7.37–7.20 (m, 25 H,
aromatic), 5.99–5.92 (m, 1 H, ꢀCHꢁCH2),
5.60 (dd, 1 H, J2%,3% 9.8 Hz, H-2%), 5.60–5.24
(m, 2 H, ꢁCH2), 5.32 (d, 1 H, J1%,2% 1.8 Hz,
H-1%), 4.93–4.40 (m, 10 H, 5×ꢀCH2Ph), 4.40
(d, 1 H, J1,2 7.9 Hz, H-1), 4.39–4.12 (m, 2 H,
ꢀCH2CHꢁCH2), 4.10 (dd, 1 H, J4,5 1.8 Hz,
H-4), 3.96 (dd, 1 H, J3%,4%. 9.8 Hz, H-3%), 3.84
(dd, 1 H, J5%,6% 6.1 Hz, H-5%), 3.71 (dd, 1 H, J2,3
9.8 Hz, H-2), 3.65 (m, 2 H, H-6), 3 56 (t, 1 H,
J5,6 6.1 Hz, H-5), 3.49 (dd, 1 H, J3,4 3.1 Hz,
H-3), 3.39 (t, 1 H, J4%,5% 9.8 Hz H-4%), 2.07 (s, 3
H, CH3), 1.25 (d, 3 H, H-6). Anal. Calcd for
C52H58O11: C, 72.69; H, 6.81. Found: C, 71.55;
H, 6.69.
di - O - benzyl - a -
2,3,6-tri-O-benzyl-
L
- rhamnopyranosyl - (1“4)-
-galactopyranose. A mix-
D
ture of this compound and CH2Cl2 (12 mL)
was added to CCl3CN (9 mL) and DBU (two
drops) at 0 °C. After 2 h the mixture was
diluted with CHCl3, washed by water, dried
(Na2SO4), and evaporated. The residue was
chromatographed on silica gel with 100:1
CHCl3–MeOH as eluent to provide 15 (917
mg, 30%); Rf 0.85 (8:1 benzene–acetone).
Allyl 2 - O - acetyl - 3 - O - benzyl - 4 - O - (p-
methoxybenzyl)-h-
2,3,6 - tri - O - benzyl - h -
(1“2)-3,4-di-O-benzyl-h-
L
-rhamnopyranosyl-(1“4)-
D
- galactopyranosyl-
-rhamnopyranosyl-
2-O-Acetyl-3-O-benzyl-4-O-(p-methoxyben-
L
zyl)-h-
L
-rhamnopyranosyl-(1“4)-2,3,6-tri-O-
-galactopyranosyl trichloroacetimi-
(1“4)-2,3,6-tri-O-benzyl-i- -galactopyran-
D
benzyl-h-
D
oside (16).—A mixture of compound 11 (32
mg, 0.04 mmol), compound 14 (51 mg, 0.05
date (14).—A mixture of compound 12 (660
mg, 0.74 mmol), PdCl2 (657 mg), and NaOAc
(610 mg) in 90% aq AcOH (48 mL) was
stirred overnight at 35 °C. The insoluble mate-
rial was filtered off, the filtrate was concen-
trated, and the residue was extracted with
EtOAc. The extract was washed with water,
satd aq NaHCO3, and satd NaCl, dried
(Na2SO4), and concentrated. The residue was
chromatographed on silica gel with 25:1 ben-
zene–acetone as eluent to give 2-O-acetyl-3-O-
,
mmol), 4 A MS (50 mg), and CH2Cl2 (5 mL)
was stirred under argon and then at rt in the
dark. Silver triflate (1.3 mg) was added to the
mixture, and stirring was continued overnight.
The mixture was filtered through a pad of
Celite and diluted with CHCl3. The filtrate
was washed with water and aq NaHCO3,
dried over Na2SO4, filtered, and concentrated.
The residue was purified by column chro-
matography using 5:1 hexane–EtOAc as elu-
ent to provide 16 (32 mg, 49%); Rf 0.54 (8:1
benzyl-4-O-(p-methoxybenzyl)-a-
L
-rhamno-
-galacto-
1
pyranosyl-(1“4)-2,3,6-tri-O-benzyl-
D
benzene–acetone); H NMR data (CDCl3): l
pyranose. To a solution of this compound in
CH2Cl2 (10 mL) was added CCl3CN (1.68
mL) and DBU (two drops) at 0 °C. After 2 h
the mixture was diluted CHCl3, washed with
water, dried (Na2SO4), and concentrated. The
residue was chromatographed on silica gel
using 100:1 CHCl3–MeOH as eluent to give
14 (128 mg, 17%).
7.36–6.83 (m, 49 H, aromatic), 6.00–5.92 (m,
1 H, ꢀCHꢁ), 5.60 (dd, 1 H, J2,3 3.1 Hz, H-2d),
5.33 (d, 1 H, J1,2 1.8 Hz, H-1b), 5.31–5.19 (m,
2 H, CH2ꢁ), 5.21 (d, 1 H, J1,2 1.8 Hz, H-1d),
4.91–4.25 (m, 20 H, 10×ꢀCH2Ph), 4.78 (d, 1
H, J1,2 3.7 Hz, H-1c), 4.41–4.10 (m, 2 H,
ꢀCH2CHꢁCH2), 4.37 (dd, 1 H, J1,2 7.9 Hz,
H-1a), 4.32 (t, 1 H, J5,6 7.6 Hz, H-5a), 4.23
(dd, 1 H, J2,3 3.1 Hz, H-2b), 4.16 (bd, 1 H,
H-4c), 4.08 (bd, 1 H, H-4a), 3.95 (dd, 1 H, J3,4
2.5 Hz, H-3c), 3.93 (dd, 1 H, J3,4 9.8 Hz,
H-3d), 3.90 (dd, 1 H, J3,4 9.8 Hz, H-3b), 3.84
(m, 1 H, J5,6 6.1 Hz, H-5d), 3.79 (s, 3 H,
OCH3), 3.75 (m, 1 H, J5,6 6.1 Hz, H-5b), 3.71
(dd, 1 H, J2,3 10.4 Hz, H-2c), 3.67 (dd, 1 H,
2-O-Acetyl-3,4-di-O-benzyl-h-
L
-rhamnopyr-
-galacto-
anosyl-(1“4)-2,3,6-tri-O-benzyl-h-
D
pyranosyl trichloroacetimidate (15).—To a so-
lution of compound 13 (2.73 g, 3.18 mmol) in
90% AcOH (207 mL) was added PdCl2 (2.82
g) and NaOAc (4.33 g). The mixture was
stirred overnight at 35 °C. The insoluble mate-

M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
91
(s, 3 H, CH3), 1.23 (d, 3 H, H-6b), 1.22 (d, 3
H, H-6d). 13C NMR data (CDCl3): l 169.9
(CꢁO), 103.1 (JC-1, H-1 159 Hz, C-1a), 98.9,
97.9 (JC-1, H-1 174 Hz, JC-1, H-1 176 Hz, C-1b,
C-1d), 95.5 (JC-1, H-1 170 Hz, C-1c), 55 2
(OCH3), 21.1 (CH3CO), 18.1, 18.1 (C-6b, C-
6d). Anal. Calcd for C100H110O21: C, 62.88;
H, 6.73. Found C, 62.79; H, 6.80.
J2,3 9.8 Hz, H-2a), 3.65 (m, 2 H, H-6c), 3.54
(t, 1 H, J5,6 6.7 Hz, H-5c), 3.50 (t, 1 H, J4,5
9.2 Hz, H-4b), 3.45 (dd, 1 H, J3,4 2.4 Hz,
H-3a), 3.43 (m, 2 H, H-6a), 3.37 (t, 1 H, J4,5
9.2 Hz, H-4d), 2.07 (s, 3 H, CH3), 1.24 (d, 3
H, H-6b), 1.21 (d, 3 H, H-6d). 13C NMR
data (CDCl3): l 103.0 (JC-1, H-1 157 Hz, C-1a),
99.0 (JC-1, H-1 174 Hz, C-1d), 97 9 (JC-1, H-1
170 Hz, C-1b), 95.5 (JC-1, H-1 168 Hz, C-1c).
Anal. Calcd for C52H58O11: C, 72.69; H, 6.81.
Found: C, 71.55; H, 6.69. Anal. Calcd for
C100H110O21: C, 62.88; H, 6.73. Found: C,
62.94; H, 6.79.
Allyl 3-O-benzyl-4-O-(p-methoxybenzyl)-h-
-rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-
L
h-
h-
D
-galactopyranosyl-(1“2) - 3,4-di-O-benzyl-
-rhamnopyranosyl-(1“4)-2,3,6-tri-O-ben-
-galactopyranoside (18).—To a mix-
L
zyl-i-
D
Allyl 2 - O - acetyl - 3,4 - di - O - benzyl - h -
rhamnopyranosyl-(1“4)-2,3,6-tri-O-benzyl-
h- galactopyranosyl-(1“2)-3-O-benzyl-4-O-
(p-methoxybenzyl) - h - - rhamnopyranosyl-
(1“4)-2,3,6-tri-O-benzyl-i- -galactopyran-
L
-
ture of compound 16 (32 mg, 0.024 mmol) in
MeOH (5 mL) was added NaOMe (20 mg).
The mixture was stirred for 2 h at rt, then
neutralized with Amberlite IR-120B (H+),
filtered, and evaporated to give 18 (29 mg,
93%); Anal. Calcd for C98H108O20: C, 73.30;
H, 6.78. Found: C, 73.39; H, 6.84.
D
L
D
oside (17).—A mixture of compound 10 (479
mg, 0.57 mmol), compound 15 (917 mg, 0.95
,
mmol), 4 A MS (1.05 g), and dry CH2Cl2 (15
Allyl 3,4-di-O-h-
2,3,6 - tri - O - benzyl - h -
(1“2)-3-O-benzyl-4-O-(p-methoxybenzyl)-
h- -rhamnopyranosyl-(1“4)-2,3,6-tri-O-ben-
zyl-i- -galactopyranoside (19).—To a solu-
L
-rhamnopyranoyl-(1“4)-
mL) was stirred for 2 h under an argon at-
mosphere at rt in the dark. Silver triflate (36
mg) was then added, and the mixture was
stirred overnight. The mixture was diluted
with CHCl3, filtered, washed with water and
aq NaHCO3, dried (Na2SO4), filtered, and
concentrated. The residue was purified by
column chromatography using 5:1 hexane–
EtOAc as eluent to give 17 (621 mg, 67%); Rf
D
- galactopyranosyl-
L
D
tion of compound 17 (39 mg, 0.024 mmol) in
MeOH (5 mL) was added NaOMe (20 mg),
and the mixture was stirred at rt for 2 h. The
mixture was neutralized with Amberlite IR-
120B (H+), filtered, and concentrated to give
19 (36 mg, 93%); Anal. Calcd for C98H108O20:
C, 73.30; H, 6.78. Found: C, 73.21; H, 6.82.
1
0.54 (8:1 benzene–acetone); H NMR data
(CDCl3): l 7.36–6.81 (m, 49 H, aromatic),
6.00–5.92 (m, 1 H, ꢀCHꢁ), 5.60 (dd, 1 H, J2,3
3.1 Hz, H-2d), 5.35 (d, 1 H, J1,2 1.8 Hz,
H-1b), 5.35–5.19 (m, 2 H, CH2ꢁ), 5.23 (d, 1
H, J1,2 1.8 Hz, H-1d), 4.92–4.26 (m, 20 H,
10×ꢀCH2Ph), 4.91 (d, 1 H, J1,2 3.7 Hz, H-
1c), 4.45–4.10 (m, 2 H, ꢀCH2CHꢁCH2), 4.37
(d, 1 H, J1,2 7.3 Hz, H-1a), 4.32 (t, 1 H, J5,6
6.7 Hz, H-5a), 4.23 (bd, 1 H, J2,3 3.1 Hz,
H-2b), 4.17 (bd, 1 H, H-4), 4.07 (bd, 1 H,
H-4a), 3.95 (dd, 1 H, J3,4 3.1 Hz, H-3c), 3.93
(dd, 1 H, J3,4 9.8 Hz, H-3d), 3.89 (dd, 1 H,
J3,4 9.8 Hz, H-3b), 3.85 (m, 1 H, J5,6 6.1 Hz,
H-5d), 3.76 (s, 3 H, OCH3), 3.74 (m, 1 H, J5,6
6.1 Hz, H-5b), 3.71 (dd, 1 H, J2,3 10.4 Hz,
H-2c), 3.67 (t, 1 H, J2,3 8.5 Hz, H-2a), 3.66
(m, 2 H, H-6c), 3.54 (t, 1 H, J5,6 6.1 Hz,
H-5c), 3.49 (t, 1 H, J4,5 9.2 Hz, H-4b), 3.44
(dd, 1 H, J3,4 3.1 Hz, H-3a), 3.42 (m, 2 H,
H-6a), 3.39 (t, 1 H, J4,5 9.2 Hz, H-4d), 2.07
Propyl O-h-
-galactopyranosyl-(1“2)-O-h-
pyranosyl - (1“4) - O - i - - galactopyranoside
L
-rhamnopyranosyl-(1“4)-O-
h-D
L
-rhamno-
D
(20).—To a solution of compound 19 (32
mg, 0.02 mmol) in MeOH (1 mL) was added
10% Pd–C (18.7 mg). The mixture was
stirred overnight under H2, and then filtered
and concentrated. The residue was chro-
matographed on IATROBEADS using 5:3
CHCl3–MeOH as eluent to provide 20 (13
1
mg, 74%); H NMR data (CD3OD): l 5.27
(bd, 1 H, H-1d), 5.18 (bd, 1 H, H-1b), 4.99
(d, 1 H, J1,2 7.2 Hz, H-1c), 4.22 (d, 1 H, J1,2
7.9 Hz, H-1a), 1.64 (m, 2 H, ꢀCH2CH2CH3),
1.28, 1.25 (each d, 6 H, H-6b, H-6d), 0.95 (t,
3
H, ꢀCH2CH2CH3). 13C NMR data
(CD3OD): l 105.0 (C-1a), 103.4 (C-1b), 101.1
(C-1d), 99.7 (C-1c), 24.0 (CH2CH2CH3), 18.2,

92
M. Maruyama et al. / Carbohydrate Research 325 (2000) 83–92
Acknowledgements
18.0 (C-1b, C-1d), 10.8 (CH2CH2CH3). Anal.
Calcd for C27H48O19: C, 47.93; H, 7.15.
Found: C, 47.85; H, 7.21.
The authors would like to thank Miss T.
Naito for performing the microanalyses at
Nagoya City University, Nagoya, Japan. This
work was supported by a Grant-in-Aid for
Scientific Research (No. 09672156) from the
Ministry of Education, Science, Sports and
Culture of Japan.
Propyl O-h-
(h- -galactopyranosyluronic acid)-(1“2)-O-
h- -rhamnopyranosyl-(1“4)-O-(i- -galacto-
L
-rhamnopyranosyl-(1“4)-O-
D
L
D
pyranosid)uronic acid (21).—A solution of
compound 20 (18.8 mg, 0.028 mmol), KBr
(0.6 mg), and 2,2,6,6-tetramethylpiperidine 1-
oxide (TEMPO) (0.6 mg) in satd aq NaHCO3
(0.3 mL) was stirred at rt, while a solution of
NaOCl (0.37 mL) was added dropwise over a
period of 1 h. The mixture was neutralized
with Amberlite IR-120B (H+), filtered, and
concentrated. The residue was chro-
matographed using Sephadex LH-20 using
water as eluent to remove reagents, and then
by HPLC using water as eluent to provide 21
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