Synthesis of oligosaccharide derivatives related to those from sanqi, a Chinese herbal medicine from Panax notoginseng

Article abstract of DOI:10.1016/S0008-6215(02)00013-7

Oligosaccharide derivatives from sanqi, a Chinese herbal medicine derived from Panax notoginseng, methyl β-D-galactopyranosyl-(1→3)-[α-L-arabinofuranosyl- (1→6)]-α-D-galactopyranoside, diosgenyl β-D-galactopyranosyl-(1→3)-[α-L-arabinofuranosyl- (1→6)]-α-D-galactopyranoside, and methyl β-D-galactopyranosyl-(1→3)-[α-L-arabinofuranosyl- (1→6)]-α-D-galactopyranosyl-(1→4)-β-D- galactopyranosyl-(1→3)-[α-L-arabinofuranosyl-(1→6)] -α-D-galactopyranoside, were synthesized under standard glycosylation conditions. An unexpected α-(1→4) linkage was formed predominantly in the presence of neighboring participation group during regioselective synthesis of hexasaccharide via 3+3 strategy.

Full text of DOI:10.1016/S0008-6215(02)00013-7

Carbohydrate Research 337 (2002) 485–491
www.elsevier.com/locate/carres
Synthesis of oligosaccharide derivatives related to those from
sanqi, a Chinese herbal medicine from Panax notoginseng
Feng Yang, Yuguo Du*
Research Center for Eco-En6ironmental Sciences, Academia Sinica, PO Box 2871, Beijing 100085, PR China
Received 16 November 2001; accepted 4 January 2002
Abstract
Oligosaccharide derivatives from sanqi, a Chinese herbal medicine derived from Panax notoginseng, methyl b-
osyl-(1“3)-[a- -arabinofuranosyl-(1“6)]-a- -galactopyranoside, diosgenyl b- -galactopyranosyl-(1“3)-[a- -arabinofuranosyl-
(1“6)]-a- -galactopyranoside, and methyl b- -galactopyranosyl-(1“3)-[a- -arabinofuranosyl-(1“6)]-a- -galactopyranosyl-
(1“4)-b- -galactopyranosyl-(1“3)-[a- -arabinofuranosyl-(1“6)]-a- -galactopyranoside, were synthesized under standard gly-
D-galactopyran-
L
D
D
L
D
D
L
D
D
L
D
cosylation conditions. An unexpected a-(1“4) linkage was formed predominantly in the presence of neighboring participation
group during regioselective synthesis of hexasaccharide via 3+3 strategy. © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Natural products; Neighboring-group effects; Stereoselectivity; Glycosylations; Oligosaccharide
1. Introduction
2. Results and discussion
Panax notoginseng (Burk.) F.H. Chen. (sanqi) is
widely used in China as a medicine to promote the
circulation of blood.1 It is very effective in treating
coronary heart diseases and angina pectoris. The active
components in sanqi are believed to be carbohydrates
Regioselective glycosylation of 2,3,5-tri-O-benzoyl-a-
L
-arabinofuranosyl trichloroacetimidate6 (1) and
methyl
(2) in dry CH2Cl2 with TMSOTf as a promoter af-
forded methyl 2,3,5-tri-O-benzoyl-a- -arabinofura-
nosyl-(1“6)-3,4-O-isopropylidene-a- -galactopyrano-
3,4-O-isopropylidene-a-
D
-galactopyranoside7
L
and their saponins.2 Structural analysis shows that b-
D-
D
side (3, 76%). Acetylation of 3 with acetic anhydride in
pyridine (“4), followed by cleavage of acetonide in
90% TFA (“5, 92%) and regioselective condensation
galactopyranosyl-(1“3)-[a-
L
-arabinofuranosyl-(1“6)]-
D
-galactopyranose is the major fraction in active sanqi
oligosaccharides.3 In stereocontrolled glycosylation, the
best-established method is based on the participation of
a group at C-2 of the glycosyl donor to direct 1,2-trans
glycosidic bond formation.4 Although the experimental
conditions for this procedure have been modified case
by case, the basic principle of neighboring-group partic-
ipation has not been obliterated.5 We herein present the
synthesis of sanqi oligosacchride derivatives and an
unexpected result in regio- and stereoselective synthesis
of a hexasaccharide in the presence of neighboring-
group participation during a 3+3 glycosylation.
with 2,3,4,6-tetra-O-benzoyl-a-D-galactopyranose tri-
chloroacetimidate (6) furnished trisaccharide 7. Deac-
ylation of 7 in ammonia-saturated methanol furnished
the methyl glycoside of sanqi oligosaccharide repeating
unit 8 in 61% yield (from 5, Scheme 1).
To further study structure–activity relationships, we
turned our attention to the synthesis of sanqi oligosac-
charide analogues. Thus, 6-O-tert-butyldiphenylsilyl-
1,2-O-ethylidene-a-
D
-galactopyranose8
(9)
was
glycosylated with 6 in the presence of TMSOTf to give
the (1“3)-linked disaccharide 10 (94%) which was
subsequently desilylated with TBAF9 in THF to give
the 4,6-diol 11. Coupling of 11 with donor 1 under
standard glycosylation conditions gave trisaccharide 12
(54%). Trisaccharide imidate 15 was prepared in 64%
* Corresponding
fax: +86-10-62923563.
E-mail address: ygdu@mail.rcees.ac.cn (Y. Du).
author.
Tel.:
+86-10-62914475;
0008-6215/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(02)00013-7

486
F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
overall yield via protection group manipulation of 12,
i.e., de-ethylidenation,8 acetylation (“13), deacetyl-
ation10 on the anomeric carbon (“14) and finally
Schmidt activation.11 Condensation of 15 and diosgenin
furnished saponin derivative 16 that was treated with
aqueous 1 N NaOH in methanol (pH 9) to give the
completed sanqi saponin analogue 17 (60% for two
steps).
residue III appears at l 5.21 ppm (J1,2 3.6 Hz) in the 1H
NMR, while the corresponding C-1III at l 98.5 ppm
(JC-1,H-1 171 Hz) in 13C NMR spectroscopy, indicating
an a linkage between carbohydrate units II and III in
22. Compared to acceptor 21, the chemical shift of
C-4II in 22 moved downfield to l 78.6 ppm from l 68.8
ppm, while the C-3IIs of 21 and 22 appear at l 72.2 and
l 71.9 ppm in 13C NMR spectra, respectively, which
confirms the C-4 glycosylation of unit II. Furthermore,
acetylated 22 gave H-3II at l 5.08 ppm, further confirm-
ing this assignment. Decreasing the reaction tempera-
ture (−40 °C) and/or adding more TMSOTf (up to 0.4
equiv) did not improve the yield of this coupling reac-
With the aim to synthesize the dimerized sanqi
oligosaccharide, disaccharide
phenyl 2,6-di-O-benzoyl-3,4-O-isopropylidene-1-thio-b-
-galactopyranoside7 (18) to yield methyl 2,6-di-O-ben-
zoyl-3,4-O-isopropylidene-b- -galactopyranosyl-(1“3)-
[2,3,5-tri-O-benzoyl-a- -arabinofuranosyl-(1“6)]-2-O-
acetyl-a- -galactopyranoside (19), which was then
5 was coupled with
D
D
1
tion. The major byproducts showed H NMR spectra
L
that could not be identified and gave smaller masses
compared to that of 22. Full deprotection of 22 in
ammonia-saturated methanol gave the a-(1“4)-linked
sanqi dimer 23 in 93% yield. The potential bioactivity
of compounds 8, 17 and 23 is currently under
investigation.
D
acetylated in pyridine with acetic anhydride to give 20.
Removal of the acetonide group in 90% TFA then
afforded the trisaccharide 3,4-diol 21 in a total yield of
42% from 5 (Scheme 2).
The coupling reaction of 15 and 21 was carried out in
anhydrous CH2Cl2 in the presence of TMSOTf at 0 °C.
Surprisingly, a 41% yield of the a-(1“4)-linked dimer
22 was isolated from the reaction mixture. To deter-
mine the correct assignments of this intriguing struc-
3. Experimental
1
ture, we have run H NMR, coupled 13C NMR and
General methods.—Optical rotations were deter-
mined at 25 °C with a Perkin–Elmer model 241 MC
1
1H–1H, H–13C COSY experiments. The H-1 of sugar
Scheme 1. Reagents and conditions: (a) TMSOTf, CH2Cl2; 76% for 3; 82% for 7; 94% for 10; 61% for 16; (b) Ac2O, Pyr; (c) 90%
TFA; 92%; (d) NH3, MeOH; 74%; (e) TBAF, THF; 77%; (f) 90% TFA; Ac2O, Pyr; (g) NH3, THF–MeOH (7:3); 69% from 12;
(h) Cl3CCN, DBU; 93%; (i) 1 N NaOH, MeOH; 99%.

F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
487
Scheme 2. (a) NIS, TMSOTf; 45%; (b) Ac2O, Pyr; (c) 90% TFA; 94%; (d) TMSOTf, CH2Cl2; 41%; (e) NH3, MeOH; 93%.
1
1
automatic polarimeter. H NMR, 13C NMR and H–
(s, 3 H, OCH3), 3.85 (dd, 1 H, J6a,6b 10.3, J6a,5 7.1 Hz,
H-6a), 4.10 (dd, 1 H, J6b,5 5.4 Hz, H-6b), 4.26 (ddd, 1
H, J5,4 2.4 Hz, H-5), 4.27 (dd, 1 H, J4,3 5.3 Hz, H-4),
4.31 (dd, 1 H, J3,2 8.0 Hz, H-3), 4.60–4.62 (m, 1 H,
H-4%), 4.70 (dd, 1 H, J5a%,5b% 11.9, J5a%,4% 4.9 Hz, H-5a%),
4.84 (d, 1 H, J1,2 3.6 Hz, H-1), 4.87 (dd, 1 H, J5b%,4% 3.4
Hz, H-5b%), 4.97 (dd, 1 H, H-2), 5.41 (s, 1 H, H-1%), 5.56
(d, 1 H, J3%,4% 5.0 Hz, H-3%), 5.63 (s, 1 H, H-2%), 7.27–
8.06 (m, 15 H, Ph); Anal. Calcd for C38H40O14: C,
63.33; H, 5.55. Found: C, 63.60; H, 5.48.
1H, H–13C COSY spectra were recorded with ARX
1
400 spectrometers for solutions in CDCl3, CD3OD and
D2O. Chemical shifts are given in ppm downfield from
internal Me4Si. Mass spectra were measured using
MALDITOF-MS with a-cyano-4-hydroxycinnamic
acid (CCA) as the matrix, or recorded with a VG
PLATFORM mass spectrometer using the electrospray
ionization (ESI) technique to introduce the sample.
High-resolution thin-layer chromatography (HRTLC)
was performed on Silica Gel HF254 with detection by
charring with 30% (v/v) H2SO4 in MeOH or in some
cases by UV detection. Column chromatography was
conducted by elution of a column (16×240 mm, 18×
300 mm, 35×400 mm) of silica gel (100–200 mesh)
with EtOAc–petroleum ether (bp 60–90 °C) as the
eluent. Solutions were concentrated at B60 °C under
diminished pressure.
Methyl
2,3,5-tri-O-benzoyl-h-L-arabinofuranosyl-
(1“6)-2-O-acetyl-h-
D
-galactopyranoside (5).—A solu-
tion of 4 (5 g, 6.93 mmol) in CH2Cl2 (2 mL) and 90%
TFA was stirred at rt for about 10 min at which time
TLC indicated the reaction was complete. The mixture
was neutralized with aq NaHCO3, then extracted with
CH2Cl2. The organic phase was dried over Na2SO4 and
concentrated. The residue was subjected to column
chromatography on silica gel with 2:1 petroleum ether–
EtOAc as the eluent to give 5 as a syrup (4.34 g, 92%):
Methyl
2,3,5-tri-O-benzoyl-h-
(1“6)-2-O-acetyl-3,4-O-isopropylidene-h-
L
-arabinofuranosyl-
-galacto-
D
pyranoside (4).—To a mixture of 1 (11.16 g, 18.4
mmol) and 2 (3.52 g, 15 mmol) in dry CH2Cl2 (100 mL)
at 0 °C was added TMSOTf (85 mL, 0.47 mmol). The
mixture was stirred at this temperature for 2.5 h, then
neutralized with Et3N and concentrated. The residue
was subjected to column chromatography on silica gel
with 2:1 petroleum ether–EtOAc as the eluent to give 3
(7.7 g, 76%). To a mixture of 3 (7.15 g, 10.5 mmol) in
pyridine (15 mL) was added Ac2O (2.5 mL). The mix-
ture was stirred at rt for 10 h, then co-evaporated with
toluene to dryness. The residue was subjected to silica
gel column chromatography with 3:1 petroleum ether–
EtOAc as the eluent to give 4 as a syrup (6.7 g, 88%):
1
[h]D +52° (c 1, CHCl3); H NMR (300 MHz, CDCl3):
2.06 (s, 3 H, COCH3), 3.29 (s, 3 H, OCH3), 3.75–3.78
(m, 1 H, H-6a), 3.91–4.01 (m, 3 H, H-3, H-5 and
H-6b), 4.04 (d, 1 H, J4,3 3.3 Hz, H-4), 4.58–4.63 (m, 2
H, H-4% and H-5a%), 4.70–4.80 (m, 1 H, H-5b%), 4.82 (d,
1 H, J1,2 3.6 Hz, H-1), 4.96 (dd, 1 H, J2,3 10.2 Hz, H-2),
5.30 (s, 1 H, H-2%), 5.46 (s, 1 H, H-1%), 5.51 (d, 1 H, J
3.0 Hz, H-3%), 7.19–8.00 (m, 15 H, Ph); Anal. Calcd for
C35H36O14: C, 61.76; H, 5.33. Found: C, 61.55; H, 5.42.
Methyl
(1“6)-[2,3,4,6-tetra-O-benzoyl-i-
(1“3)]-2-O-acetyl-h- -galactopyranoside (7).—To a
2,3,5-tri-O-benzoyl-h-
L
-arabinofuranosyl-
D
-galactopyranosyl-
D
1
solution of 5 (0.8 g, 1.17 mmol) and 6 (1.023 g, 1.38
mmol) in dry CH2Cl2 (5 mL) at 0 °C was added TMS-
[h]D +78° (c 1, CHCl3); H NMR (400 MHz, CDCl3):
1.24, 1.52 (2 s, 6 H, 2 CH3), 2.13 (s, 3 H, COCH3), 3.38

488
F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
OTf (23 mL, 0.13 mmol). The mixture was stirred at this
temperature for 2 h, then neutralized with Et3N, and
the solvents were evaporated under reduced pressure.
The residue was subjected to column chromatography
on silica gel with 1.5:1 to 1:1 petroleum ether–EtOAc
as the eluent to give 7 as a foam (1.215 g, 82%): [h]D
EtOAc as the eluent to give 10 (R, S mixture) as a
syrup (11.46 g, 94%): 1H NMR (300 MHz, CDCl3):
1.04 (s, 9 H, C(CH3)3), 1.24, 1.40 (2 d, 3 H, CHCH3,
the ratio of the isomers is about 1.7:1.3), 3.76–3.94 (m,
4 H), 4.09–4.15 (m, 1 H, H-5), 4.32–4.47 (m, 3 H, H-4,
H-5% and H-6a%), 4.56–4.64 (m, 1 H, H-6b%), 5.20–5.26
(m, 2 H), 5.45 (br d, 1 H, H-1), 5.60–5.80 (m, 2 H),
6.00 (d, 1 H, J4%,3% 3 Hz, H-4%), 7.20–8.12 (m, 30 H, Ph);
Anal. Calcd for C58H58O15Si: C, 68.09; H, 5.71. Found:
C, 68.37; H, 5.69.
1
+95° (c 1, CHCl3); H NMR (400 MHz, CDCl3): 1.53
(s, 3 H, COCH3), 3.32 (s, 3 H, OCH3), 3.46 (dd, 1 H,
J6a,6b 11.2, J6a,5 3.1 Hz, H-6aI), 3.90 (dd, 1 H, J6b,5 8.0
Hz, H-6bI), 3.98 (dd, 1 H, H-5I), 4.10 (dd, 1 H, J3,2
10.2, J3,4 3.2 Hz, H-3I), 4.22 (d, 1 H, H-4I), 4.32 (br t,
1 H, H-5II), 4.46 (dd, 1 H, J6a,6b 11.0, J6a,5 5.3 Hz,
H-6aII), 4.57–4.61 (m, 2 H, H-6bII and H-4III), 4.72 (dd,
1 H, J5a,5b 12.1, J5a,4 4.8 Hz, H-5aIII), 4.86 (dd, 1 H,
J5b,4 3.7 Hz H-5bIII), 4.90 (d, 1 H, J1,2 3.7 Hz, H-1I),
5.00 (d, 1 H, J1,2 8.0 Hz, H-1II), 5.15 (dd, 1 H, H-2I),
5.38 (s, 1 H, H-2III), 5.57 (s, 1 H, H-1III), 5.59 (d, 1 H,
J3,4 3.0 Hz, H-3III), 5.62 (dd, 1 H, J3,2 10.4, J3,4 3.4 Hz,
H-3II), 5.83 (dd, 1 H, H-2II), 5.98 (d, 1 H, H-4II),
7.21–8.08 (m, 35 H, Ph); 13C NMR (100 MHz, CDCl3):
20.00 (COCH3), 54.96 (OCH3), 62.01 (C-6II), 63.70
(C-5III), 67.04 (C-6I), 67.93 (C-4II), 68.63 (C-2II), 69.11
(C-2I), 69.31 (C-3II), 69.35 (C-5II), 71.33 (C-5I), 71.68
(C-4I), 77.79 (C-3I), 77.94 (C-3III), 81.19 (C-4III), 81.91
(C-2III), 96.76 (C-1I), 101.90 (C-1II), 106.05 (C-1III),
128.24, 128.37, 128.43, 128.46, 128.63, 128.66, 129.76,
129.78, 129.94, 132.99, 133.34, 133.36, 133.45, 133.52,
164.87, 165.26, 165.44, 165.51, 165.61, 165.82, 166.14,
169.92; Anal. Calcd for C69H62O23: C, 65.81; H, 4.96.
Found: C, 65.60; H, 5.09.
2,3,4,6-Tetra-O-benzoyl-i-D-galactopyranosyl-(1“3)-
1,2-O-ethylidene-h- -galactopyranose (11).—To a solu-
D
tion of 10 (10.5 g, 10.3 mmol) in THF (100 mL) was
added TBAF (7.048 g, 23.7 mmol). The mixture was
stirred at rt for 2.5 h at which time TLC indicated the
reaction was complete. The solvents were evaporated,
and the residue was subjected to column chromatogra-
phy on silica gel with 1:1 petroleum ether–EtOAc
as the eluent to give 11 (6.2 g, 77%) as a syrup;
MALDITOF-MS: Calcd for C42H40O15, 784.24 [M];
Found, 807.30 [M+Na]+. Treatment of 11 (20 mg)
with Ac2O in pyridine gave 2,3,4,6-tetra-O-benzoyl-b-
D
-galactopyranosyl-(1“3)-4,6-di-O-acetyl-1,2-O-ethyli-
1
dene-a-D -galactopyranose as a syrup: H NMR (400
MHz, CDCl3): 1.23 (d, 1.7 H, J 3.6 Hz, CHCH3), 1.34
(d, 1.3 H, J 3.6 Hz, CHCH3), 1.85 (s, 1.7 H, COCH3),
1.89 (s, 1.3 H, COCH3), 2.05, 2.06 (br s, 3 H, COCH3),
3.90 (t, 0.43 H, J3,4 4.0 Hz, H-3), 4.06–4.19 (m, 4 H),
4.24 (t, 0.57 H), 4.34 (t, 1 H), 4.40–4.47 (m, 1 H),
4.63–4.69 (m, 1 H), 5.11 (q, 0.43 H, J 4.8 Hz, CHCH3),
5.22–5.30 (m, 1.57 H), 5.39 (d, 0.43 H, J1%,2% 4.8 Hz),
5.49 (d, 1 H), 5.54 (br s, 0.57 H), 5.62–5.65 (br d, 1 H),
5.71–5.77 (m, 1 H), 5.99 (br s, 1 H, H-4%), 7.24–8.12
(m, 20 H, Ph).
Methyl h-
L
-arabinofuranosyl-(1“6)-[i-D-galactopy-
ranosyl-(1“3)]-h-
D
-galactopyranoside (8).—A solution
of 7 (0.7 g, 0.556 mmol) in ammonia-saturated MeOH
(100 mL) was stirred at rt for 7 days. The solvents were
evaporated, and the residue was purified on a Sephadex
LH-20 column with MeOH as the eluent to give 8 as
2,3,5-Tri-O-benzoyl-h-
[2,3,4,6-tetra-O-benzoyl-i-
L
-arabinofuranosyl-(1“6)-
-galactopyranosyl-(1“3)]-
D
1,2-O-ethylidene-h- -galactopyranose (12).—To a solu-
D
1
solid (0.2 g, 74%): [h]D +23° (c 1, CH3OH); H NMR
tion of 11 (2.4 g, 3.06 mmol) and 1 (1.89 g, 3.11 mmol)
in CH2Cl2 (20 mL) at 0 °C were added TMSOTf (40
mL, 0.22 mmol). The mixture was stirred at this temper-
ature for 1 h at which time TLC indicated the reaction
was complete. It was then neutralized with Et3N and
concentrated. The residue was subjected to column
chromatography on silica gel with 2:1 petroleum ether–
EtOAc as the eluent to give 12 as a syrup (2.03 g, 54%).
One isomer gave 1H NMR (300 MHz, CDCl3) as
follows: 1.17 (d, 3 H, J 4.8 Hz, CHCH3), 1.18 (s, 3 H,
COCH3), 3.59 (dd, 1 H, J6a,6b 10.2, J6a,5 6.3 Hz, H-6aI),
3.79 (dd, 1 H, J6b,5 5.4 Hz H-6bI), 4.07–4.14 (m, 3 H),
4.26 (m, 1 H), 4.41 (dd, 1 H, J 11.4, 6.0 Hz), 4.57–4.64
(m, 3 H), 4.79 (m, 1 H), 5.20–5.26 (m, 3 H), 5.48–
5.63 (m, 5 H), 5.75 (dd, 1 H, J 10.5, 7.6 Hz), 5.96 (d,
1 H, J4,3 3.3 Hz, H-4II), 7.23–8.12 (m, 35 H, Ph);
MALDITOF-MS: Calcd for C68H60O22, 1228.36 [M];
Found, 1251 [M+Na]+.
(400 MHz, CD3OD): 3.41 (s, 3 H, OCH3), 3.56 (m, 2
H), 3.66–3.79 (m, 6 H), 3.88–3.93 (m, 4 H), 3.99–4.05
(m, 4 H), 4.22 (d, 1 H, J4,3 2.4 Hz, H-4I), 4.52 (d, 1 H,
J1,2 7.6 Hz, H-1II), 4.77 (d, 1 H, J1,2 3.8 Hz, H-1I), 5.00
(s, 1 H, H-1III); 13C NMR (100 MHz, CD3OD): 55.61
(OCH3), 62.46, 62.88, 68.22, 70.00, 70.13, 70.52, 70.62,
72.88, 74.45, 76.52, 78.65, 81.52, 83.40, 85.43, 100.99,
106.34, 109.72; ESIMS: Calcd for C18H32O15, 488.17
[M]; Found, 487 [M−H]+.
2,3,4,6-Tetra-O-benzoyl-i-D-galactopyranosyl-(1“3)-
6-O-tert-butyldiphenylsilyl-1,2-O-ethylidene-h-
D
-galac-
topyranose (10).—To a solution of 9 (5.3 g, 11.9 mmol)
and 6 (9.34 g, 12.6 mmol) in CH2Cl2 (40 mL) at 0 °C
was added TMSOTf (90 mL, 0.5 mmol) under an N2
atmosphere. The mixture was stirred at this tempera-
ture for 1.5 h at which time TLC indicated the reaction
was complete. It was then neutralized with Et3N and
concentrated. The residue was subjected to column
chromatography on silica gel with 4:1 petroleum ether–
2,3,5-Tri-O-benzoyl-h-
[2,3,4,6-tetra-O-benzoyl-i-
L
-arabinofuranosyl-(1“6)-
-galactopyranosyl-(1“3)]-
D

F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
489
2,4-di-O-acetyl-h-
D
-galactopyranosyl trichloroacetimi-
NMR (400 MHz, CDCl3): 0.71 (s, 3 H, CH3), 0.79 (d,
3 H, J 6.4 Hz, CH3), 0.81 (s, 3 H, CH3), 0.84–0.87 (m,
2 H), 0.97 (d, 3 H, J 6.8 Hz, CH3), 1.01–1.15 (m, 2 H),
1.21–1.30 (m, 5 H), 1.42–2.09 (m, 24 H), 1.55 (s, 3 H,
COCH3), 2.17 (s, 3 H, COCH3), 3.34 (m, 1 H, 3a-H),
3.37 (t, 1 H, J 10.9 Hz, H-26a), 3.47 (dd, 1 H, J26b,25 4.1
Hz, H-26b), 3.72 (dd, 1 H, J6a,6b 12.1, J6a,5 8.4 Hz,
H-6aI), 3.79–3.83 (m 2 H, H-5I and H-6bI), 3.87 (dd, 1
H, J3,2 10.0, J3,4 3.6 Hz, H-3I), 4.17 (t, 1 H, H-5II), 4.29
(dd, J6a,6b 11.2, J6a,5 7.0 Hz, H-6aII), 4.38 (d, 1 H, J1,2
8.1 Hz, H-1I), 4.29 (t, 1 H, J 6.8 Hz, H-16), 4.58 (m, 3
H, H-6aII, H-4III and H-5aIII), 4.82 (dd, 1 H, J5b,5a 11.9,
J5b,4 3.3 Hz, H-5bIII), 4.88 (d, 1 H, J1,2 8.0 Hz, H-1II),
5.11 (dd, 1 H, H-2I), 5.24 (d, J6,7a 4 Hz, H-6 of
diosgenyl), 5.34 (s, 1 H, H-1III), 5.51–5.56 (m, 3 H,
H-3II, H-3III and H-2III), 5.60 (d, 1 H, H-4I), 5.69 (dd,
1 H, J2,3 10.4 Hz, H-2II), 5.90 (d, 1 H, J4,3 4 Hz, H-4II),
7.23–8.09 (m, 35 H, Ph); 13C NMR (100 MHz, CDCl3):
14.57 (C-21), 16.25 (C-18), 17.17 (C-27), 19.15 (C-19),
20.22 (COCH3), 20.68 (C-11), 20.85 (COCH3), 26.93
(C-24), 29.44 (C-2), 30.31 (C-25), 31.32 (C-23), 31.40
(C-8), 31.84 (C-15), 31.98 (C-7), 36.69 (C-10), 36.84
(C-1), 38.95 (C-4), 39.71 (C-12), 40.23 (C-13), 41.61
(C-20), 49.75 (C-9), 56.38 (C-14), 61.65 (C-6II), 62.12
(C-17), 63.68 (C-5III), 66.60 (C-6I), 66.86 (C-26), 67.73
(C-4II), 69.36 (C-4I), 69.93 (C-2II), 70.62 (C-2I), 71.19
(C-5II), 71.47 (C-3II), 73.22 (C-5I), 77.76 (C-3I), 77.92
(C-3III), 80.10 (C-3), 80.81 (C-16), 80.92 (C-4III), 82.23
(C-2III), 100.40 (C-1I), 101.43 (C-1II), 106.38 (C-1III),
109.29 (C-22), 121.553 (C-6), 128.24, 128.33, 128.51,
128.54, 128.68, 129.02, 129.19, 129.38, 129.45, 129.77,
129.88, 129.95, 130.10, 133.05, 133.24, 133.34, 133.55,
133.66, 140.45 (C-5), 164.74, 165.32, 165.46, 165.61,
165.73, 165.91, 166.17, 168.66, 170.11; MALDITOF-
MS: Calcd for C97H102O26, 1682.67 [M]; Found,
1705.31 [M+Na]+. Anal. Calcd for C97H102O26: C,
69.19; H, 6.11. Found: C, 69.51; H, 5.93.
date (15).—To a solution of 12 (1.52 g, 1.24 mmol) in
CH2Cl2 (2 mL) was added aq 90% TFA (15 mL). The
mixture was stirred at rt for 2 h, then co-evaporated
with toluene under reduced pressure. The residue was
dissolved in pyridine (10 mL) and Ac2O (5 mL), and
stirred at rt for 6 h, then concentrated to dryness to
give crude 13. Crude 13 dissolved in 7:3 ammonia-satu-
rated THF–MeOH (100 mL) was stirred at rt for 30
min, and the solvents were then evaporated at 35 °C.
The residue was subjected to column chromatography
on silica gel with 1.5:1 petroleum ether–EtOAc as the
eluent to give 14 as a syrup (1.1 g, 69% from 12).
Compound 14 (0.73 g, 0.567 mmol) was dissolved in
CH2Cl2 (6 mL), then CCl3CN (0.5 mL, 0.5 mmol) and
DBU (50 mL) were added at 0 °C. The mixture was
stirred at rt for 2 h, then concentrated. The residue was
subjected to column chromatography on silica gel with
1.5:1 petroleum ether–EtOAc as eluent to give 15 as a
syrup (0.749 g, 93%): [h]D +59° (c 1, CHCl3); 1H
NMR (400 MHz, CDCl3): 1.51 (s, 3 H, COCH3), 2.23
(s, 3 H, COCH3), 3.68 (dd, 1 H, J6a,6b 11.0, J6a,5 4.3 Hz,
H-6aI), 3.82 (dd, 1 H, J6b,5 4.8 Hz, H-6bI), 4.18 (dd, 1
H, H-5II), 4.27 (dd, 1 H, J3,2 10.2, J3,4 3.2 Hz, H-3I),
4.29–4.36 (m, 2 H, H-5I and H-6aII), 4.59–4.69 (m, 3
H, H-6bII, H-4III and H-5aIII), 4.85 (dd, 1 H, J5b,5a 11.9,
J5b,4 3.1 Hz, H-5bIII), 4.97 (d, 1 H, J1,2 7.8 Hz, H-1II),
5.23 (dd, 1 H, J2,1 3.6 Hz, H-2I), 5.53–5.58 (m, 3 H,
H-3II, H-3III and H-2III), 5.72 (dd, 1 H, J2,3 10.4 Hz,
H-2II), 5.83 (d, 1 H, H-4I), 5.91 (d, 1 H, J4,3 3.2 Hz,
H-4II), 6.46 (d, 1 H, H-1I), 7.25–8.11 (m, 35 H, Ph),
8.49 (s, 1 H, NH); 13C NMR (100 MHz, CDCl3): 19.72
(COCH3), 20.72 (COCH3), 61.63 (C-6II), 63.52 (C-5III),
65.82 (C-6I), 67.66 (C-4II), 68.64 (C-2I), 69.26 (C-4I),
69.93 (C-2II), 71.17 (C-5II), 71.31 (C-5I), 71.31 (C-3II),
73.84 (C-3I), 77.95 (C-3III), 81.16 (C-4III), 82.12 (C-2III),
93.56 (C-1I), 101.16 (C-1II), 106.03 (C-1III), 128.17,
128.25, 128.43, 128.48, 128.61, 128.95, 128.99, 129.12,
129.18, 129.31, 129.57, 129.69, 129.72, 129.81, 129.88,
130.06, 132.97, 133.32, 133.46, 133.61, 160.53, 164.69,
165.26, 165.39, 165.51, 165.74, 165.85, 166.16, 169.64,
169.73; MALDITOF-MS: Calcd for C72H62Cl3NO24,
1429.27 [M]; Found, 1452.17 [M+Na]+. Anal. Calcd
for C72H62Cl3NO24: C, 60.41; H, 4.37. Found: C, 60.68;
H, 4.29.
Diosgenyl i-
D
-galactopyranosyl-(1“3)-[h-
L-arabino-
furanosyl-(1“6)]-i-
D
-galactopyranoside (17).—To
a
solution of 16 (0.32 g, 0.19 mmol) in MeOH (100 mL)
was added aq 1 N NaOH until pH 9–10 was attained.
The mixture was stirred at rt overnight, then neutral-
ized with Amberlite IR-120 (H+). The solvents were
evaporated, and the residue was subjected to column
chromatography on Sephadex LH-20 with MeOH as
the eluent to give 17 as an amorphous solid (0.16 g,
Diosgenyl 2,3,4,6-tetra-O-benzoyl-i-
osyl-(1“3)-[2,3,5-tri-O-benzoyl-h- -arabinofuranosyl-
(1“6)]-2,4-di-O-acetyl-i- -galactopyranoside (16).—
To a solution of 15 (0.53 g, 0.37 mmol) and diosgenin
(0.185 g, 0.45 mmol) in CH2Cl2 (2 mL) at 0 °C was
added TMSOTf (25 mL, 0.14 mmol). The mixture was
stirred at this temperature for about 1 h, then neutral-
ized with Et3N and concentrated. The residue was
subjected to column chromatography on silica gel with
1.5:1 petroleum ether–EtOAc as the eluent to give 16
D-galactopyran-
1
L
99%): [h]D −51° (c 1, CH3OH); H NMR (400 MHz,
D
CD3OD): 0.81 (d, 3 H, J 6.4 Hz, CH3), 0.83 (s, 3 H,
CH3), 0.98 (d, 3 H, J 6.8 Hz, CH3), 1.07 (s, 3 H, CH3),
0.97–1.0 (m, 1 H), 1.09–2.04 (m, 25 H), 2.29 (t, 1 H, J
12.0 Hz), 2.45 (d, 1 H, J 10.8 Hz), 3.32–4.13 (m, 27 H),
4.41 (t, 1 H, J 7.6 Hz, H-16), 4.42 (d, 1 H, J1,2 7.0 Hz,
H-1I), 4.44 (d, 1 H, J1,2 7.6 Hz, H-1II), 4.95 (s, 1 H,
H-1III), 5.41 (br s, 1 H, H-6 of diosgenyl); 13C NMR
(100 MHz, DOCD3): 14.90 (C-21), 16.79 (C-18), 17.50
(C-27), 19.87 (C-19), 21.99 (C-11), 29.88 (C-24), 30.76
1
(0.38 g, 61%) as a foam: [h]D +30° (c 1, CHCl3); H

490
F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
(C-25), 31.43 (C-23), 32.42 (C-15), 32.74 (C-7), 32.79
(C-2), 33.17 (C-8), 37.99 (C-10), 38.48 (C-1), 39.75
(C-12), 40.92 (C-13), 41.41 (C-20), 42.89 (C-4), 51.61
(C-9), 57.80 (C-14), 62.56 (C-17), 63.02 (C-6II), 63.74
(C-5III), 67.84 (C-26), 67.96 (C-6I), 69.85 (C-4II), 70.24
(C-4I), 71.51 (C-2II), 71.56 (C-2I), 74.60 (C-5II), 74.63
(C-3II), 76.72 (C-5I), 78.88 (C-3), 80.04 (C-16), 82.19
(C-3I), 83.43 (C-3III), 84.73 (C-4III), 85.70 (C-2III),
102.63 (C-1I), 106.27 (C-1II), 109.29 (C-22), 110.55 (C-
1III), 122.50 (C-6), 142.04 (C-5); MALDITOF-MS:
Calcd for C44H70O17, 870.46 [M]; Found 893.39 [M+
Na]+.
H-5bIII, H-1II, H-6aII), 4.81 (dd, 1 H, J6b,5 3.2 Hz,
H-6bII), 4.87 (d, 1 H, J1,2 3.6 Hz, H-1I), 4.95 (dd, 1 H,
H-2I), 5.25 (t, 1 H, J1,2 7.3 Hz, H-2II), 5.33 (s, 1 H,
H-1III), 5.52 (s, 1 H, H-2III), 5.53 (d, 1 H, H-4I), 5.56 (d,
1 H, J3,4 4.8 Hz, H-3III), 7.26–8.10 (m, 25 H, Ph);
MALDITOF-MS: Calcd for C60H60O22, 1132.36 [M];
Found, 1155.4 [M+Na]+.
Methyl
(1“6)-[2,6-di-O-benzoyl-i-
2,4-di-O-acetyl-h- -galactopyranoside (21).—A solu-
2,3,5-tri-O-benzoyl-h-L-arabinofuranosyl-
D
-galactopyranosyl-(1“3)]-
D
tion of 20 (1.00 g, 1.13 mmol) in CH2Cl2 (2 mL) and
90% TFA were stirred at rt for about 10 min, at which
time TLC indicated the reaction was complete. The
mixture was neutralized with aq NaHCO3, then ex-
tracted with CH2Cl2. The organic phase was dried over
Na2SO4 and concentrated. The residue was subjected to
column chromatography on silica gel with 1:1
petroleum ether–EtOAc as the eluent to give 21 as a
syrup (0.915 g, 94%): [h]D +38° (c 1, CHCl3); 1H
NMR (400 MHz, CDCl3): 1.68, 2.11 (2 s, 6 H, 2
COCH3), 3.28 (s, 3 H, OCH3), 3.60 (dd, 1 H, J6a,6b 10.9,
J6a,5 3.1 Hz, H-6aI), 3.76–3.84 (m, 3 H, H-3II, H-5II and
H-6bI), 4.01 (br s, 1 H, H-5I and H-4II), 4.16 (dd, 1 H,
J3,2 10.4, J3,4 3.2 Hz, H-3I), 4.58–4.62 (m, 3 H, H-4III,
H-5aIII and H-5bIII), 4.68 (dd, 1 H, J6a,6b 12.0, J6a,5 4.4
Hz, H-6aII), 4.69 (d, 1 H, J1,2 7.3 Hz, H-1II), 4.83 (dd,
1 H, J6b,5 3.2 Hz, H-6bII), 4.87 (4 H, d, J1,2 3.6 Hz,
H-1I), 4.94 (dd, 1 H, H-2I), 5.18 (dd, 1 H, J2,3 9.6 Hz,
H-2II), 5.33 (s, 1 H, H-1III), 5.54 (s, 1 H, H-2III), 5.55 (d,
1 H, H-4I), 5.56 (d, J3,4 5.2 Hz, H-3III), 7.26–8.08 (m,
25 H, Ph); 13C NMR (100 MHz, CDCl3): 20.28, 27.77,
55.14, 62.51 (C-5III), 63.55 (C-6II), 66.32 (C-6I), 68.41
(C-5I), 68.77 (C-4II), 70.22 (C-2I), 70.80 (C-4I), 72.26
(C-3II), 72.46 (C-5II), 72.60 (C-3I), 73.68 (C-2II), 77.85
(C-3III), 81.00 (C-4III), 82.04 (C-2III), 96.75 (C-1I),
101.26 (C-1II), 106.17 (C-1III), 128.28, 128.42, 128.47,
128.96, 129.08, 129.58, 129.64, 129.68, 129.72, 129.87,
133.012 133.22, 133.27, 133.46, 133.50, 165.30, 165.75,
166.17, 166.33, 169.83, 170.76; MALDITOF-MS: Calcd
for C57H56O22, 1092.33 [M]; Found, 1115.17 [M+Na]+
. Anal. Calcd for C57H56O22: C, 62.63; H, 5.16. Found:
C, 62.88; H, 5.02.
Methyl
(1“6)-[2,6-di-O-benzoyl-3,4-O-isopropylidene-i-
galactopyranosyl-(1“3)]-2-O-acetyl-h- -galactopyran-
2,3,5-tri-O-benzoyl-h-L-arabinofuranosyl-
D
-
D
oside (19).—To a mixture of 5 (1.22 g, 1.76 mmol) and
18 (1.2 g, 2.3 mmol) in dry CH2Cl2 (10 mL) at −20 °C
were added N-iodosuccinimide (NIS, 0.8 g, 3.57 mmol)
and TMSOTf (22 mL, 0.12 mmol). The mixture was
stirred at this temperature for 80 min, at which time
TLC indicated the reaction was complete. The mixture
was neutralized with Et3N, and concentrated. The
residue was subjected to column chromatography on
silica gel with 1.5:1 petroleum ether–EtOAc as the
eluent to give syrupy 19 (0.87 g, 45%): [h]D +28° (c 1,
1
CHCl3); H NMR (400 MHz, CDCl3): 1.26, 1.58 (s, 6
H, 2 CH3), 1.64 (s, 3 H, COCH3), 3.28 (s, 3 H, OCH3),
3.64 (d, 1 H, J 9.2 Hz, H-6aI), 3.83–3.88 (m, 2 H, H-4I,
H-6bI), 3.96 (d, 1 H, J 9.6 Hz, H-5I), 4.26 (s, 1 H, J4,3
4.1 Hz, H-4II), 4.26 (br s, 1 H, H-3I), 4.32 (br s, 1 H,
H-3II), 4.40 (br s, 1 H, H-5II), 4.54 (d, 1 H, H-4III),
4.58–4.73 (m, 4 H, H-5aIII, H-5bIII, H-1II, H-6aII), 4.81
(d, 1 H, J 10.8 Hz, H-6bII), 4.85 (d, 1 H, J1,2 4.4 Hz,
H-1I), 5.07 (dd, 1 H, J2,3 6.8 Hz, H-2I), 5.25 (br s, 1 H,
H-2II), 5.45 (s, 1 H, H-1III), 5.53 (s, 1 H, H-2III), 5.55 (d,
1 H, J3,4 4.0 Hz, H-3III), 7.27–8.04; MALDITOF-MS:
Calcd for C58H58O21, 1090.35 [M]; Found, 1113 [M+
Na]+. Anal. Calcd for C58H58O21: C, 63.85; H, 5.36.
Found: C, 64.04; H, 5.19.
Methyl
(1“6)-[2,6-di-O-benzoyl-3,4-O-isopropylidene-i-
galactopyranosyl-(1“3)]–2,4-di-O-acetyl-h- -galacto-
2,3,5-tri-O-benzoyl-h-L-arabinofuranosyl-
D
-
D
pyranoside (20).—Compound 19 (1.85 g, 1.69 mmol)
and Ac2O (1 mL) were dissolved in pyridine (5 mL) at
rt. The mixture was stirred at rt for 10 h, then co-evap-
orated with toluene. The residue was subjected to
column chromatography on silica gel with 3:1
petroleum ether–EtOAc as the eluent to give quantita-
Methyl
osyl-(1“3)-[2,3,5-tri-O-benzoyl-h-
(1“6)]-2-O-acetyl-h- -galactopyranosyl-(1“4)-2,6-
di-O-benzoyl-i- -galactopyranosyl-(1“3)-[2,3,5-tri-
O-benzoyl-h- -arabinofuranosyl-(1“6)]-2,4-di-O-ace-
tyl-h- -galactopyranoside (22).—To a solution of 15
2,3,4,6-tetra-O-benzoyl-i-
D-galactopyran-
L
-arabinofuranosyl-
D
D
L
D
1
tive 20 as a syrup: [h]D +11° (c 1, CHCl3); H NMR
(0.794 g, 0.56 mmol) and 21 (0.519 g, 0.47 mmol) in dry
CH2Cl2 (5 mL) at 0 °C was added TMSOTf (10 mL,
0.06 mmol). The mixture was stirred at this temperature
for 2 h, then neutralized with Et3N, and the solvents
were evaporated. The residue was subjected to column
chromatography on silica gel with 1.5:1 petroleum
ether–EtOAc as the eluent to give 22 as an amorphous
(400 MHz, CDCl3): 1.35, 1.61 (2 s, 6 H, CH3), 1.73,
2.10 (2 s, 6 H, COCH3), 3.27 (s, 3 H, OCH3), 3.56 (dd,
1 H, J6a,6b 10.9, J6a,5 3.2 Hz, H-6aI), 3.91 (dd, 1 H, J6b,5
4.0 Hz, H-6bI), 4.00–4.03 (m, 1 H, H-5I), 4.09–4.11 (m,
1 H, H-4II), 4.13 (dd, 1 H, J3,2 10.2, J3,4 3.4 Hz, H-3I),
4.32 (dd, 1 H, H-3II), 4.38–4.42 (m, 1 H, H-5II), 4.59–
4.62 (m, 2 H, H-5aIII and H-4III), 4.66–4.73 (m, 3 H,
1
solid (0.46 g, 41%): [h]D +91° (c 1, CHCl3); H NMR

F. Yang, Y. Du / Carbohydrate Research 337 (2002) 485–491
491
(400 MHz, CDCl3): 1.51 (s, 3 H, COCH3), 1.60 (s, 6 H,
2 COCH3), 2.12 (s, 3 H, COCH3), 3.31 (s, 3 H, OCH3),
3.63–3.66 (m, 2 H, H-6aI and H-6aIII), 3.72 (dd, 1 H,
J6b,6a 11.3, J6b,5 4.3 Hz, H-6bIII), 3.83–3.86 (m, 3 H,
H-3II, H-6bI and H-5II), 4.03 (d, 1 H, J4,3 2.4 Hz, H-4II),
4.10 (m, 2 H, H-6aII and H-5I), 4.20 (dd, 1 H, J3,2 10.4,
J3,4 3.5 Hz, H-3I), 4.25–4.35 (m, 2 H, H-6aIV and
H-5IV), 4.51–4.60 (m, 5 H, H-3III, H-4VI, H-5aV, H-4V
and H-6bII), 4.65–4.73 (m, 4 H, H-6bIV, H-5bV, H-5aVI,
H-1II), 4.80 (dd, 1 H, J5b,5a 11.8, J5b,4 3.2 Hz, H-5bVI),
4.85 (m, 1 H, H-5III), 4.92 (d, 1 H, J1,2 3.6 Hz, H-1I),
5.03 (dd, 1 H, H-2I), 5.16 (d, 1 H, J1,2 7.7 Hz, H-1IV),
5.21 (d, 1 H, J1,2 3.6 Hz, H-1III), 5.22 (dd, 1 H, J2,3 10.4
Hz, H-2III), 5.32 (dd, 1 H, J2,3 10.4, J2,1 7.6 Hz, H-2II),
5.34 (s, 1 H, H-1V), 5.36 (s, 1 H, H-1VI), 5.42 (d, 1 H,
J2,3 1.6 Hz, H-2VI), 5.54–5.62 (m, 4 H, H-2V, H-3V,
H-4I, H-3VI), 5.63 (dd, 1 H, J3,2 10.4, J3,4 3.3 Hz,
H-3IV), 5.77 (dd, 1 H, H-2IV), 5.81 (d, 1 H, J4,3 3.1 Hz,
H-4III), 5.96 (d, 1 H, H-4IV), 7.25–8.10 (m, 60 H, Ph);
13C NMR (100 MHz, CDCl3): 19.83, 20.17, 20.81, 20.95
(4 COCH3), 55.20 (OCH3), 61.39 (C-6IV), 61.46 (C-6II),
63.31 (C-5V), 63.52 (C-5VI), 65.68 (C-6III), 66.81 (C-6I),
67.75 (C-4IV), 68.88 (C-5I), 69.40 (C-5III), 69.76 (C-2III),
69.91 (C-2IV), 70.05 (C-2I), 70.17 (C-4III), 70.52 (C-4I),
70.95 (C-5IV), 71.60 (C-3IV), 71.73 (C-5II), 71.92 (C-3II),
72.51 (C-2II), 73.55 (C-3I), 73.90 (C-3III), 77.51 (C-3V),
77.89 (C-3VI), 78.64 (C-4II), 80.30 (C-4V), 81.24 (C-4VI),
81.84 (C-2V), 82.67 (C-2VI), 96.79 (C-1I), 98.50 (C-1III),
101.51 (C-1IV), 101.67 (C-1II), 106.06 (C-1V), 106.21
(C-1VI), 128.18, 128.21, 128.26, 128.35, 128.39, 128.44,
128.47, 128.54, 129.51, 129.67, 129.72, 129.78, 129.84,
129.92, 130.01, 133.45, 165.36, 165.49, 165.52, 165.66,
165.69, 165.74, 166.15, 169.74, 169.91, 170.14, 170.32;
MALDITOF-MS: Calcd for C127H116O45, 2360.68 [M];
4.96 (d, 1 H, J1,2 3.6 Hz), 4.20 (s, 1 H), 5.20 (d, 1 H, J1,2
1.1 Hz); 13C NMR (100 MHz, D2O): 56.03 (OCH3),
58.42, 61.07, 61.80, 62.01, 67.20, 68.06, 68.21, 68.43,
69.42, 69.84, 70.02, 70.08, 71.91 (3 C), 71.96, 72.67,
73.04, 73.37, 75.69, 75.86, 77.23, 77.34, 78.62, 79.74,
80.20, 81.64, 81.90, 84.62, 84.67, 100.16 (C-1I, JC-1,H-1
173 Hz), 101.10 (C-1III, JC-1,H-1 171 Hz), 105.22 (C-1IV,
JC-1,H-1 164 Hz), 105.39 (C-1II, JC-1,H-1 165 Hz), 108.24
(C-1V, JC-1,H-1 173 Hz), 108.72 (C-1VI, 174 Hz); ESI-MS
Calcd for C83H72O23S, 944.3 [M]; Found, 962.6 [M+
NH4]+.
Acknowledgements
This work was supported by National Nature Science
Foundation of China (Projects 39970179 and
29972053).
References
1. Chinese Herbs and Compatibility; Chen, P. Ed.; Beijing:
Science Press, 1997, p. 452.
2. The Pharmacopoeia Committee of PR China. Pharmaco-
poeia (I); Beijing: People’s Health Press, 1995.
3. Fang, J. personal communication.
4. (a) Schmidt, R. R.; Kinzy, W. Ad6. Carbohydr. Chem.
Biochem. 1994, 50, 21–123;
(b) Toshima, K.; Tatsuta, K. Chem. Re6. 1993, 93, 1502–
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5. (a) Preparati6e Carbohydrate Chemistry; Hanessian, S.
Ed.; New York: Marcel Dekker, 1996;
(b) Verduyn, R.; Douwes, M.; van der Klein, P. A. M.;
Mosinger, E. M.; van der Marel, G. A.; van Boom, J. H.
Tetrahedron 1993, 49, 7301–7316;
(c) Du, Y.; Zhang, M.; Kong, F. J. Chem. Soc., Perkin
Trans. 1 2001, 2289–2293;
(d) Du, Y.; Zhang, M.; Kong, F. Tetrahedron 2001, 57,
1757–1763;
Found, 2383.32 [M+Na]+. Anal. Calcd for C127H116
-
O45: C, 64.57; H, 4.95. Found: C, 64.81; H, 5.06.
Methyl i-
furanosyl-(1“6)]-h-
galactopyranosyl-(1“3)-[h-
h- -galactopyranoside (23).—A solution of 22 (0.27 g,
D
-galactopyranosyl-(1“3)-[h-
-galactopyranosyl-(1“4)-i-
-arabinofuranosyl-(1“6)]-
L-arabino-
D
D-
(e) Boons, G.-J.; Hale, K. J. Organic Synthesis with
Carbohydrates; Sheffield Academic Press: UK, 2000.
6. Du, Y.; Pan, Q.; Kong, F. Carbohydr. Res. 2000, 323,
28–35.
7. Catelani, G.; Colonna, F.; Marra, A. Carbohydr. Res.
1988, 182, 297–300.
L
D
0.114 mmol) in ammonia-saturated MeOH (100 mL)
was stirred at rt for 7 days. The solvents were evapo-
rated, and the residue was purified on a Sephadex
LH-20 column with MeOH as the eluent to give 23 as
an amorphous solid (0.10 g, 93%): [h]D +7° (c 1,
CH3OH); 1H NMR (400 MHz, D2O): 3.38 (s, 3 H,
OCH3), 3.61–4.10 (m, 32 H), 4.18 (d, 1 H, J 2.8 Hz),
4.26 (d, 1 H, J 2.4 Hz), 4.60 (d, 1 H, J1,2 7.6 Hz), 4.62
(d, 1 H, J1,2 8.0 Hz), 4.81 (1 H, overlapped by D2O),
8. Pan, Q.; Du, Y.; Kong, F.; Pan, J.; Lu, M. J. Carbohydr.
Chem. 2001, 20, 297–306.
9. Greene, T. W.; Wuts, P. G. M. Protecti6e Groups in
Organic Synthesis, 3rd ed.; New York: Wiley, 1999.
10. Fiandor, J.; Garcia-Lopez, M. T.; de las Heras, F. G.;
Mendez-Castrillon, P. P. Synthesis 1985, 1121–1123.
11. Schmidt, R. R.; Michel, J. J. Carbohydr. Chem. 1985, 4,
141–169.