Synthesis of β-D-glucose oligosaccharides from Phytophthora parasitica

Article abstract of DOI:10.1016/j.carres.2003.08.004

The glucohexaose, β-D-Glcp-(1→3)-[β-D-Glcp-(1→3)- β-D-Glcp-(1→3)-β-D-Glcp-(1→6)]-β-D-Glcp-(1→3) -D-Glcp, was synthesized as its allyl glycoside via 3+3 strategy. The trisaccharide donor, 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→3)- 2,4,6-tri-O-acetyl

Full text of DOI:10.1016/j.carres.2003.08.004

Carbohydrate Research 338 (2003) 2359ꢁ2366
/
www.elsevier.com/locate/carres
Synthesis of b-
D
-glucose oligosaccharides from Phytophthora
parasitica
Youlin Zeng, Fanzuo Kong*
Research Center for Eco-Environmental Sciences, Academia Sinica, P.O. Box 2871, Beijing 100085, PR China
Received 10 June 2003; accepted 12 August 2003
Abstract
The glucohexaose, b-
sized as its allyl glycoside via 3ꢀ
O-acetyl-b- -glucopyranosyl-(10
coupling of isopropyl 4,6-O-benzylidene-1-thio-b-
O-acetyl-4,6-O-benzylidene-a- -glucopyranosyl trichloroacetimidate (6), followed by hydrolysis, acetylation, dethiolation, and
trichloroacetimidation. Meanwhile, the trisaccharide acceptor, allyl 2,3,4,6-tetra-O-benzoyl-b- -glucopyranosyl-(103)-2-O-acetyl-
b- -glucopyranosyl-(103)-4,6-di-O-acetyl-2-O-benzoyl-a- -glucopyranoside (14), was prepared by coupling of allyl 4,6-di-O-
acetyl-2-O-benzoyl-a- -glucopyranoside (12) with 6, followed by debenzylidenation. Condensation of 14 with 11, followed by
deacylation, gave the target hexaoside. A b-(103)-linked tetrasaccharide 29 was also synthesized with methyl 2-O-benzoyl-4,6-O-
benzylidene-b- -glucopyranosyl-(103)-2,4,6-tri-O-acetyl-b- -glucopyranoside (25) as the acceptor and acylated b-(103)-linked
disaccharide 21 as the donor.
# 2003 Elsevier Ltd. All rights reserved.
D
-Glcp-(10
3 strategy. The trisaccharide donor, 2,3,4,6-tetra-O-benzoyl-b-
3)-2,4,6-tri-O-acetyl-a- -glucopyranosyl trichloroacetimidate (11), was obtained by 3-selective
-glucopyranoside (2) with 2,3,4,6-tetra-O-benzoyl-b- -glucopyranosyl-(103)-2-
/
3)-[b-
D
-Glcp-(10
/
3)-b-
D
-Glcp-(10
/
3)-b-
D
-Glcp-(10
/
6)]-b-
D
-Glcp-(10
/
3)-
D
-Glcp, was synthe-
/
D
-glucopyranosyl-(10
/
3)-2,4,6-tri-
D
/
D
D
D
/
D
D
/
D
/
D
D
/
D
/
D
/
Keywords: b-D-Glucans; Trichloroacetimidates; Regio- and stereoselective synthesis
1. Introduction
branched glucans have been synthesized by different
methods8ꢁ12; now we report the stereoselective synthesis
Glucans consisting of (10
(106)-b- -linked mono-, di-, and trisaccharide
branches having 0, 1, or 2 (103)-linked b- -glucose
/
3)-b-
D
linkages with various
of the allyl glycoside, of b-
(103)-b- -Glcp-(103)-b- -Glcp-(10
(103)- -Glcp, with benzylidenated glucose derivatives
as the key intermediates.
D
-Glcp-(10
/
3)-[b-
D-Glcp-
-Glcp-
/
D
/
D
/
D
/
6)]-b-
D
/
D
/
D
resides (Fig. 1), have been found in fruiting bodies and
culture broths of fungi such as Phytophthora parasitica,1
Sclerotium glucanicum,2 Auricularia auricula-judae,3
Pullularia pullulans,4 Pleurotus ostreatus,5 Cordyceps
ophioglossoides,6 and Ganoderma applanaum.7 Since
these glucans show antitumor activity, chemists are
interested in synthesizing the minimum active unit of
the natural polysaccharides to investigate their
2. Results and discussion
Retrosynthetic analysis reveals that the best way to
synthesize the target hexaose is to first prepare two b-
structureꢁ
activity relationships.8ꢁ11 Some linear and
/
(10/3)-linked trisaccharide fragments, then connect
them at the C-6 of the glucose residue of the trisacchar-
ide backbone. For achieving the formation of b-gluco-
sidic linkages, the use of a C-2 ester in the donor capable
of neighboring group participation is necessary. How-
* Corresponding author. Tel.: ꢀ
10-62923563.
E-mail address: fzkong@mail.reces.ac.cn (F. Kong).
/
86-10-62936613; fax: ꢀ86-
/
ever, our previous studies13 indicated that in (10
/3)-
0008-6215/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2003.08.004

2360
Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ2366
/
similarly prepared. Thus, coupling of 6 with allyl 4,6-O-
acetyl-2-O-benzoyl-a-
-glucopyranoside (12)9 furnished
b-(103)-linked trisaccharide 13 (86%). Debenzylidena-
tion of 13 afforded the trisaccharide acceptor 14 (87%).
Condensation of 14 with 11 selectively gave the (106)-
D
/
/
linked hexasaccharide 15 (64%), and subsequent deacy-
lation yielded the target hexasaccharide 16 (96%). The
1H and 13C NMR spectra of 16 showed characteristic
signals such as at d 4.86 (1 H, J1,2 3.6 Hz, a-H-1), 4.71 (1
H, J1,2 7.6 Hz, b-H-1), 4.69, 4.69, 4.60, 4.41 (4 H, J1,2 8.0
Hz, b-H-1), 102.9, 102.9, 102.8, 102.7, 102.6 (JC-1,H-1
163.2, 163.2, 165.1, 164.5, 164.3, 5 b-C-1), 97.2 (JC-1,H-1
171.6 Hz, a-C-1). The 13C NMR data of C-3 also
indicated selective C-6 glycosylation of 14 with 11;
otherwise, if C-4 were glycosylated, one more signal at
Fig. 1. Polysaccharide structure of P. parasitica.
glucosylation the glycosyl bond originally present in
either donor or acceptor controlled the stereoselectivity
of the forthcoming bond, i.e., the newly formed
glycosidic linkage had the opposite anomeric configura-
tion of that of either the donor or acceptor. With b-(10
/
3)-linked disaccharides as the acceptor and an acylated
glucosyl trichloroacetimidate as the donor, or with a b-
d 82ꢁ
For investigation of the conditions necessary for
glucose b-(103) linkage formation and preparation of
more complex glucans, coupling of the b-(103)-linked
disaccharide donor 21 with the b-(103)-linked disac-
charide acceptor 25 bearing a 4,6-O-benzylidene group
at the nonreducing end was carried out giving b-(103)-
/
84 would appear.
(10/3)-linked acylated disaccharide trichloroacetimidate
/
as the donor and a glucoside as the acceptor, a-linked
trisaccharides are always obtained in spite of the C-2
neighboring group participation. However, some re-
ports9,11 revealed that with 4,6-O-benzylidenated glu-
cose derivatives as either donor or acceptor, b-linked
oligosaccharides are readily obtained. Thus, in the
present research, the benzylidenated glucose derivatives
were applied as the key intermediates. As outlined in
/
/
/
linked tetrasaccharide 26 (60%). This is different from
the coupling that gives completely a-linked tetrasacchar-
ide13b with acylated b-(10
/
3)-linked disaccharides as the
donors and acylated b-(103)-linked disaccharides as
/
Scheme 1, isopropyl 4,6-O-benzylidene-1-thio-b-
copyranoside (2),8 obtained from 4,6-O-benzylidenation
of isopropyl 1-thio-b- -glucopyranoside, was used as
the starting material. Coupling of 2 with the donor 1
selectively afforded b-(103)-linked disaccharide 3.
D-glu-
the acceptors, indicating the important role of the 4,6-
O-benzylidene group in control of the stereoselectivity
of glycosylation (Scheme 2).
D
In summary, a convergent synthesis of glucose
/
hexasaccharide containing a b-(10
with a b-(106)-linked trisaccharide branch having 2
(103)-linked b- -glucose residues was achieved. The
/3)-linked backbone
1
Acetylation of 3 gave 4 and the 2D H NMR spectrum
of 4 clearly showed H-2 at d 5.59 with J1,2 7.8, J2,3 9.9
Hz, confirming the regioselectivity of the glycosylation.
Due to the instability of the O-benzylidene group of 4
under the coupling conditions used for the thioglycoside
donor, transformation of 4 to the corresponding tri-
chloroacetimidate donor 6 was carried out. It was
reported14 that transformation of thioglycosides to the
corresponding hemiacetals was achieved by treating the
thioglycosides with water, N-bromosuccinimide (NBS)
and catalytic TMSOTf in acetone. It was found, in our
research, that treatment of 4 with N-iodosuccinimide
(NIS) and catalytic TMSOTf in reagent grade dichlor-
omethane without addition of water gave better results,
smoothly affording the hemiacetal 5 (85%). Subsequent
trichloroacetimidation15 of 5 furnished the disaccharide
donor 6 (89%). Condensation of 6 with the acceptor 2
/
/
D
method is simple and practical, and it should be possible
to apply the process to large-scale synthesis.
3. Experimental
3.1. General methods
Optical rotations were determined at 25 8C with a
Perkinꢁ
/
Elmer Model 241-Mc automatic polarimeter.
C COSY spectra were
1H, 13C NMR and 1Hꢁ1
recorded with Bruker ARX 400 spectrometers (400
/
H, 1Hꢁ13
/
MHz for H, 100 MHz for 13C) at 25 8C for solutions
1
in CDCl3 or D2O as indicated. Mass spectra were
recorded with a VG PLATFORM mass spectrometer
using the ESI mode. Thin-layer chromatography (TLC)
was performed on silica gel HF254 with detection by
charring with 30% (v/v) H2SO4 in MeOH or in some
cases by a UV lamp. Column chromatography was
again selectively offered b-(10/3)-linked trisaccharide 7
(83%). The 3-O-selective glycosylation was confirmed by
debenzylidenation and followed by acetylation to give 9
1
whose H NMR spectrum showed H-2 at d 4.85 with
J1,2 9.9, J2,3 9.6 Hz. Reiteration of the dethioisopropyla-
tion and trichloroacetimidation yielded the trisaccharide
donor 11 (81% for two steps), suitable for construction
of the side chain. The trisaccharide backbone was also
conducted by elution of a column (16ꢂ
35ꢂ400 mm) of silica gel (100ꢁ200 mesh) with EtOAcꢁ
petroleum ether (60ꢁ90 8C) as the eluent. Solutions were
concentrated at B60 8C under reduced pressure.
/
240, 18ꢂ
/
300,
/
/
/
/
/

Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ
/
2366
2361
Scheme 1. Conditions and reagents for Scheme 1: (a) TMSOTf, CH2Cl2, ꢃ
/
20 8C to rt; (b) Ac2O, pyridine, rt, 12 h; (c) NIS,
TMSOTf, CH2Cl2, 3 h; (d) CCl3CN, CH2Cl2, DBU, rt; (e) 90% HOAcꢁH2O, reflux, 3 h; (f) MeOH, NH3, rt, 1 week.
/
3.2. General procedure for the glycosylations
3.3. Isopropyl 2,3,4,6-tetra-O-benzoyl-b-
glucopyranosyl-(103)-2-O-acetyl-4,6-O-benzylidene-1-
thio-b- -glucopyranoside (4)
D-
/
The mixture of donor and acceptor was dried together
under high vacuum for 2 h, then dissolved in anhyd
CH2Cl2. MeSiOTf (0.05 equiv) was added drop-wise at
D
As described in the general procedure, 1 (4.09 g, 5.52
mmol) and 2 (1.72 g, 5.27 mmol) were coupled, and the
product was purified by silica gel column chromatogra-
ꢃ20 8C with nitrogen protection. The reaction mixture
/
was stirred for 3 h, during which time the temperature
was gradually raised to ambient temperature. The
mixture was then neutralized with Et3N. Concentration
of the reaction mixture, followed by purification on a
silica gel column, gave the desired products.
phy with 3:1 petroleum etherꢁEtOAc as the eluent to
/
give 3 (4.53 g, 95%). To a solution of 3 (4.41 g, 4.88
mmol) in Py (20 mL) was added Ac2O (3 mL, 31.8
mmol), the reaction mixture was stirred for 4 h, at the

2362
Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ2366
/
Scheme 2. Conditions and reagents for Scheme 2: (a) TMSOTf, CH2Cl2, ꢃ
CH2Cl2, DBU, rt; (d) thiourea, CH2Cl2, MeOH, reflux, 17 h. (e) 90% HOAcꢁ
/
20 8C to rt; (b) PdCl2, CH2Cl2, MeOH, rt; (c) CCl3CN,
H2O, reflux, 3 h; (f) MeOH, NH3, rt, 1 week.
/
end of which time the TLC (4:1 petroleum etherꢁ
EtOAc) indicated that the reaction was complete. The
mixture was concentrated to dryness and then purified
/
85%). To a solution of 5 (3.00 g, 3.38 mmol) in dry
CH2Cl2 was added trichloroacetonitrile (2 mL, 9.4
mmol) and DBU (0.2 mL, 1.61 mmol). The mixture
was stirred for 3 h, at the end of which time TLC (2:1
by column chromatography with 3:1 petroleum etherꢁ
/
EtOAc as the eluent to afford 4 (4.47 g, 96%): [a]D
ꢀ
/
petroleum etherꢁEtOAc) indicated that the reaction was
complete. The reaction mixture was concentrated, and
the crude product was then purified by flash chromato-
/
1
34.78 (c 1.0, CHCl3); H NMR (CDCl3): d 8.03ꢁ
(m, 25 H, 4 Bz-H, Ph-H), 6.17 (dd, 1 H, J2,3 J3,4
Hz, H-3?), 5.81 (dd, 1 H, J3,4 J4,5 9.9 Hz, H-4?), 5.80
/
7.25
ꢄ
/
ꢄ
/
9.9
ꢄ
/
ꢄ
/
graphy with 2:1 petroleum etherꢁ/EtOAc as the eluent to
(s, 1 H, PhCH), 5.59 (dd, 1 H, J1,2 7.8, J2,3 9.9 Hz, H-2?),
5.55 (dd, 1 H, J1,2 7.8, J2,3 9.9 Hz, H-2), 5.04 (d, 1 H, J1,2
7.8 Hz, H-1?), 4.62 (dd, 1 H, J5?,6?e 2.7, J6?e, 6?a 12.1 Hz,
afford the donor 6 (3.06 g, 89%) as a foamy solid: [a]D
1
ꢀ
/
55.78 (c 1.0, CHCl3); H NMR (CDCl3): d 8.56 (s, 1
H, CNHCCl3), 7.96ꢁ7.25 (m, 25 H, 4 Bz-H, Ph-H),
6.41 (d, 1 H, J1,2 3.8 Hz, H-1), 5.84 (dd, 1 H, J3,4
J4,5 9.6 Hz, H-4?), 5.67 (dd, 1 H, J2,3 J3,4 9.6 Hz,
/
H-6?e), 4.47 (d, 1 H, J1,2 7.8 Hz, H-1), 4.53ꢁ
H, H-6?a, H-6e, H-6a), 4.03 (dd, 1 H, J2,3
Hz, H-3), 3.84ꢁ3.44 (m, 3 H, H-4, 2 H-5), 3.10 (m, 1 H,
/4.20 (m, 3
ꢄ
/
ꢄ
/
J3,4 9.9
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
/
H-3?), 5.63 (s, 1 H, PhCH), 5.52 (dd, 1 H, J1,2 7.9, J3,4
9.6 Hz, H-2?), 5.13 (d, 1 H, J1,2 7.9 Hz, H-1?), 5.00 (dd, 1
H, J1,2 3.8, J2,3 9.6 Hz, H-2), 4.46 (dd, 1 H, J5,6?e 3.4, J6?e,
CH(CH3)2), 2.23 (s, 3 H, MeCO), 1.55 (d, 6 H,
CH(CH3)2). Anal. Calcd for C52H50O15S: C, 65.95; H,
5.32. Found: C, 65.78; H, 5.29.
12.1 Hz, H-6?e), 4.35ꢁ
/
4.25 (m, 3 H, H-6?a, H-6e, H-
3.87 (m, 3 H, H-3, H-5, H-5?), 3.79 (dd, 1 H,
9.8 Hz, H-4), 1.67 (s, 3 H, MeCO). Anal.
6?a
6a), 4.03ꢁ
/
J3,4 J4,5
ꢄ
/
ꢄ
/
3.4. 2,3,4,6-Tetra-O-benzoyl-b-
3)-2-O-acetyl-4,6-O-benzylidene-a-D-glucopyranosyl
trichloroacetimidate (6)
D
-glucopyranosyl-(10
/
Calcd for C51H44Cl3NO16: C, 59.28; H, 4.29. Found: C,
59.04; H, 4.26.
NIS (1.16 g, 5.04 mmol) was added to a solution of 4
(4.01 g, 4.20 mmol) in CH2Cl2. MeSiOTf (38 mL, 0.22
3.5. Isopropyl 2,3,4,6-tetra-O-benzoyl-b-
glucopyranosyl-(103)-2,4,6-tri-O-acetyl-b-
glucopyranosyl-(103)-2,4,6-tri-O-acetyl-1-thio-b-
glucopyranoside (9)
D-
/
D-
mmol) was added drop-wise at ꢃ
/
20 8C with nitrogen
/
D-
protection. The reaction mixture was stirred for 3 h,
during which time the temperature was gradually raised
to ambient temperature. Then the mixture was neutra-
lized with Et3N. Concentration of the reaction mixture,
followed by purification on a silica gel column with 2:1
Donor 6 (2.23 g, 2.14 mmol) was coupled with acceptor
2 (607 mg, 1.86 mmol) as described in the general
procedure, and the product was purified by chromato-
petroleum etherꢁ/EtOAc as the eluent gave 5 (3.17 g,
graphy with 2:1 petroleum etherꢁEtOAc as the eluent to
/

Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ
/
2366
2363
give 7 (2.14 g, 83%). Compound 7 (1.89 g, 1.57 mmol)
was added to 90% HOAcꢁH2O (100 mL), the mixture
Hz, H-1?), 4.25 (dd, 1 H, J5?,6?e 6.5, J6?e,6?a 12.3 Hz, H-
6?e), 4.16ꢁ4.04 (m, 5 H, H-5?, H-5ƒ, H-6?a, H-6e, H-6a),
3.91 (dd, 1 H, J2,3 J3,4 9.4 Hz, H-3), 3.68 (ddd, 1 H,
J4,5 9.7, J5,6e 5.8, J5,6a 5.7 Hz, H-5), 2.09, 2.06, 2.05, 2.00,
1.97, 1.82 (s, H, MeCO). Anal. Calcd for
/
/
was refluxed for 2 h, then concentrated, and the residue
was co-evaporated with toluene (10 mL) for three times.
The residue was dried under high vacuum for 2 h, then
dissolved in Py (10 mL), and Ac2O (2 mL, 21.2 mmol)
was added. The mixture was stirred at room tempera-
ture (rt) for 3 h, at the end of which time TLC (2:1
ꢄ
/
ꢄ
/
3
C60H60Cl3NO26: C, 54.70; H, 4.59. Found: C, 54.48;
H, 4.55.
petroleum etherꢁ
was finished. The mixture was concentrated and purified
by chromatography with 2:1 petroleum etherꢁEtOAc as
the eluent to afford compound 9 as a foamy solid (1.35
/
EtOAc) suggested that the reaction
3.7. Allyl 2,3,4,6-tetra-O-benzoyl-b-
(103)-2-O-acetyl-b- -glucopyranosyl-(10
acetyl-2-O-benzoyl-a- -glucopyranoside (14)
D
-glucopyranosyl-
/
D
/
3)-4,6-di-O-
/
D
1
g, 72% for two steps): [a]D
NMR (CDCl3): d 8.02ꢁ7.25 (m, 20 H, 4 Bz-H), 5.89
(dd, 1 H, J3,4 J4,5
9.7 Hz, H-4ƒ), 5.68 (dd, 1 H,
J2,3 J3,4
9.7 Hz, H-3ƒ), 5.41 (dd, 1 H, J1,2 7.9, J2,3 9.7
Hz, H-2ƒ), 5.01 (dd, 1 H, J3,4 J4,5 9.6 Hz, H-4?),
4.90ꢁ4.78 (m, 4 H, H-1ƒ, H-2?, H-2, H-4), 4.59 (dd, 1 H,
ꢃ
/
20.18 (c 1.0, CHCl3); H
Donor 6 (2.30 g, 2.21 mmol) was coupled with acceptor
12 (783 mg, 1.92 mmol), and the product was purified by
chromatography with 3:2 petroleum etherꢁEtOAc as
the eluent to give 13 as a syrup (2.08 g, 86%).
Compound 13 (1.98 g, 1.57 mmol) was added to 90%
/
ꢄ
/
ꢄ
/
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
/
HOAcꢁH2O (100 mL), and the mixture was refluxed for
/
J5??,6??e 3.6, J6??e,6??a 12.6 Hz, H-6ƒe), 4.53 (dd, 1 H, J5??,6??a
4.6, J6??e,6??a 12.6 Hz, H-6ƒa), 4.42 (d, 1 H, J1,2 9.9 Hz, H-
1?), 4.40 (d, 1 H, J1,2 9.9 Hz, H-1), 4.29 (dd, 1 H, J5?,6?a
2 h, then concentrated to dryness, and the resultant
residue was co-evaporated with toluene (10 mL) for
three times. The residue was purified by chromatogra-
4.3, J6?e, 6?a 12.3 Hz, H-6?a), 4.16ꢁ
6?e, H-6a), 4.01 (dd, 1 H, J5,6a 2.4, J6e,6a 12.3 Hz, H-6?a),
3.89 (dd, 1 H, J2,3 J3,4 9.6 Hz, H-3?), 3.85 (dd, 1 H,
J2,3 J3,4 9.6 Hz, H-3), 3.65ꢁ3.52 (m, 2 H, H-5, H-5?),
3.11 (m, 1 H, CH(CH3)2), 2.12, 2.06, 2.03, 1.99, 1.95,
1.89 (6 s, 18 H, 6 MeCO), 1.55 (d, 6 H, CH(CH3)2).
Anal. Calcd for C61H66O25S: C, 59.51; H, 5.40. Found:
C, 59.52; H, 5.39.
/
4.10 (m, 3 H, H-5ƒ, H-
phy with 1:1 petroleum etherꢁ
give 14 (1.63 g, 87%): [a]D 41.88 (c 1.0, CHCl3); H
NMR (CDCl3): d 8.10ꢁ7.22 (m, 25 H, 5 Bz-H), 5.84
(dd, 1 H, J3,4 J4,5
9.8 Hz, H-4ƒ), 5.80 (m, 1 H, CH2ꢀ
CH ꢁCH2), 5.55 (dd, 1 H, J2,3 J3,4 9.8 Hz, H-3ƒ),
5.46 (dd, 1 H, J1,2 7.9, J2,3 9.8 Hz, H-2ƒ), 5.22 (dd, 1 H, J
1.3, 17.2 Hz, CH2ꢀCHꢁCH2), 5.12 (dd, 1 H, J 1.3, 10.2
Hz, CH2ꢀCHꢁCH2), 5.06 (d, 1 H, J1,2 3.7 Hz, H-1),
4.97 (dd, 1 H, J1,2 3.7, J2,3 9.9 Hz, H-2), 4.88 (dd, 1 H,
J3,4 J4,5 9.8 Hz, H-4), 4.79ꢁ4.75 (m, 2 H, H-2?, H-
6ƒe), 4.63 (d, 1 H, J1,2 7.9 Hz, H-1ƒ), 4.51 (d, 1 H, J1,2 8.0
Hz, H-1?), 4.35ꢁ4.31 (m, 2 H, H-4?, H-6aƒ), 4.18ꢁ3.91
(m, 7 H, 2 CH2ꢀCHꢁCH2, H-5ƒ, H-6?e, H-6?a, H-6e, H-
6a), 3.68 (ddd, 1 H, J4,5 9.8 Hz, J5,6e 4.8, J5,6a 4.6 Hz, H-
5?), 3.48 (dd, 1 H, J2,3 J3,4 9.3 Hz, H-3), 3.37ꢁ3.32
/
EtOAc as the eluent to
1
ꢀ
/
ꢄ
/
ꢄ
/
/
ꢄ
/
ꢄ
/
/
ꢄ
/
ꢄ
/
/
/
ꢄ
/
ꢄ
/
/
/
/
/
3.6. 2,3,4,6-Tetra-O-benzoyl-b-
3)-2,4,6-tri-O-acetyl-b- -glucopyranosyl-(10
tri-O-acetyl-a- -glucopyranosyl trichloroacetimidate (11)
D
-glucopyranosyl-(10
/
ꢄ
/
ꢄ
/
/
D
/
3)-2,4,6-
D
/
/
/
/
The solution of 9 (1.12 g, 0.94 mmol) and NIS (0.26 g,
1.23 mmol) in CH2Cl2 was cooled to ꢃ20 8C, then
/
ꢄ
/
ꢄ
/
/
MeSiOTf (2 mL, 0.10 mmol) was added drop-wise with
nitrogen protection. The solution was stirred for 3 h,
during which time the temperature of the reaction
mixture was gradually raised to ambient temperature.
The mixture was neutralized with Et3N. Concentration
of the reaction mixture, followed by purification of the
crude product on a silica gel column with 2:1 petroleum
(m, 2 H, H-3?, H-5), 2.09, 2.03, 1.03 (3 s, 9 H, 3 MeCO).
Anal. Calcd for C62H62O24: C, 62.52; H, 5.25. Found: C,
62.45; H, 5.23.
3.8. Allyl 2,3,4,6-tetra-O-benzoyl-b-
(103)-[2,3,4,6-tetra-O-benzoyl-b- -glucopyranosyl-(10
3)-2,4,6-tri-O-acetyl-b- -glucopyranosyl-(103)-2,4,6-
tri-O-acethyl-b- -glucopyranosyl-(106)]-2-O-acetyl-b-
-glucopyranosyl-(103)-4,6-di-O-acetyl-2-O-benzoyl-a-
-glucopyranoside (15)
D-glucopyranosyl-
/
D
/
D
/
etherꢁ/EtOAc as the eluent gave 10 as a syrup. A mixture
D
/
of 10, trichloroacetonitrile (1 mL, 4.69 mmol), and DBU
(0.1 mL, 0.81 mmol) in dry CH2Cl2 (20 mL) was stirred
for 3 h and then concentrated. The residue was purified
D
D
/
by flash chromatography (2:1 petroleum etherꢁ
to give donor 11 as a foamy solid (998 mg, 81% for two
steps from 9 through 11): [a]D
6.48 (c 1.0, CHCl3); 1H
NMR (400 MHz, CDCl3): d 8.68 (s, 1 H, CNHCCl3),
8.02ꢁ7.25 (m, 20 H, 4 Bz-H), 6.42 (d, 1 H, J1,2 3.7 Hz,
H-1), 5.90 (dd, 1 H, J3,4 J4,5
9.7 Hz, H-4ƒ), 5.64 (dd,
1 H, J2,3 J3,4
9.7 Hz, H-3ƒ), 5.38 (dd, 1 H, J1,2 7.9,
J2,3 9.8 Hz, H-2ƒ), 5.02ꢁ4.81 (m, 5 H, H-1ƒ, H-2?, H-2,
H-4?, H-4), 4.56 (m 2 H, 2 H-6ƒ), 4.46 (d, 1 H, J1,2 8.1
/
EtOAc)
Donor 11 (421 mg, 0.32 mmol) and acceptor 14 (331 mg,
0.28 mmol) were coupled as described in the general
procedure, and the product was purified by chromato-
ꢀ
/
graphy with 1:1 petroleum etherꢁ
furnish 15 (420 mg, 64%): [a]D
1.38 (c 1.0, CHCl3); 1H
NMR (CDCl3): d 8.10ꢁ7.23 (m, 45 H, 9 Bz-H), 5.92
(dd, 1 H, J3,4 J4,5 9.7 Hz, H-4), 5.85 (dd, 1 H, J3,4
J4,5 CH ꢁCH2), 5.72
9.8 Hz, H-4), 5.80 (m, 1 H, CH2ꢀ
(dd, 1 H, J2,3 J3,4 9.6 Hz, H-3), 5.54 (dd, 1 H, J2,3
/EtOAc as the eluent to
/
ꢀ
/
ꢄ
/
ꢄ
/
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
/
ꢄ
/
/
/
ꢄ
/
ꢄ
/
ꢄ
/

2364
Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ2366
/
J3,4
ꢄ
/
9.8 Hz, H-3), 5.47ꢁ
/
5.42 (m, 2 H, 2 H-2), 5.22 (dd,
CHꢁCH2), 5.12 (dd, 1 H, J
CH2), 5.07 (d, 1 H, J1,2 3.6 Hz,
H-1), 5.03 (d, 1 H, J1,2 9.4 Hz, H-1), 4.97ꢁ4.78 (m, 6 H,
4 H-1, H-2, H-4), 4.68ꢁ4.54 (m, 5 H, 3 H-2, H-4, H-6),
4.44ꢁ4.31 (m, 4 H, H-4, 3 H-6), 4.22ꢁ3.89 (m, 14 H, H-
4, 2 CH2ꢀCHꢁCH2, 3 H-5, 8 H-6), 3.73ꢁ3.24 (m, 7 H, 4
afforded 19 (1.37 g, 91%). To a solution of 19 in CH2Cl2
(60 mL) and CH3OH (30 mL) was added PdCl2 (50 mg,
0.28 mmol), and the reaction mixture was stirred at rt
1 H, J 1.2, 17.2 Hz, CH2ꢀ
1.2, 10.4 Hz, CH2ꢀCHꢁ
/
/
/
/
/
until TLC (2:1 petroleum etherꢁEtOAc) indicated that
/
/
the reaction was complete. Then the mixture was
filtered, the solution was concentrated to dryness, and
the residue was purified by flash chromatography with
/
/
/
/
/
H-3, 3 H-5), 2.16, 2.09, 2.06, 2.04, 2.00, 1.98, 1.95, 1.90
1.03 (9 s, 27 H, 9 MeCO); 13C NMR (100 MHz, CDCl3),
d 170.8, 170.8, 170.7, 169.9, 169.2, 169.0, 168.6, 168.3,
168.3 (9 C, 9 MeCO), 166.2, 166.1, 165.9, 165.8, 165.6,
165.3, 165.3, 164.9 (9 C, 9 PhCO), 133.8ꢁ
128.2 (9 PhCO, ꢀCH2ꢀCHꢁCH2), 118.3 (1 C, ꢀ
CHꢁCH2), 101.8, 101.8, 101.6, 101.1, 100.9, 95.1 (6 C-1,
JC-1,H-1 161.1, 161.1, 167.5, 163.6, 168.0, 177.4 Hz),
86.4, 79.2, 78.5, 77.2, 76.5, 74.4, 73.1ꢁ71.3, 69.6ꢁ67.6,
63.8, 60.8 (C-2ꢁ6, ꢀCH2ꢀCHꢁCH2), 22.7, 22.7,22.7,
3:2 petroleum etherꢁEtOAc as the eluent to give 20 as a
/
foamy solid. A mixture of 20, trichloroacetonitrile (1.0
mL, 4.95 mmol) and DBU (0.1 mL, 0.65 mmol) in dry
CH2Cl2 (20 mL) was stirred for 3 h and then concen-
trated. The residue was purified by flash chromatogra-
/
133.2, 130.2ꢁ
/
/
/
/
/
CH2ꢀ
/
phy with 2:1 petroleum etherꢁ
give 21 as a syrup (1.23 g, 80% for two steps): [a]D
58.68 (c 1.0, CHCl3); 1H NMR (CDCl3): d 8.55 (s, 1 H,
CNHCCl3), 7.81ꢁ7.13 (m, 10 H, 2 Bz-H), 6.56 (d, 1 H,
J1,2 3.6 Hz, H-1), 5.31 (dd, 1 H, J1,2 J2,3 9.5 Hz, H-
2?), 5.24ꢁ5.12 (m, 4 H, H-2, H-3?, H-4, H-4?), 4.88 (d, 1
H, J1,2 9.5 Hz, H-1?), 4.44 (dd, 1 H, J5,6?e 4.6, J6?e,6?a 12.5
Hz, H-6?e), 4.39 (dd, 1 H, J2,3 J3,4 9.6 Hz, H-3),
4.30ꢁ4.09 (m, 5 H, H-6?a, H-6e, H-6a, H-5, H-5?), 3.95,
/EtOAc as the eluent to
/
ꢀ
/
ꢄ
/
/
/
/
/
/
/
/
ꢄ
/
ꢄ
/
20.6, 20.6, 20.6, 20.2, 20.2 (9 C, 9 MeCO). Anal. Calcd
for C120H120O49: C, 61.43; H, 5.16. Found: C, 61.45; H,
5.15.
/
ꢄ
/
ꢄ
/
/
3.9. Allyl b-
glucopyranosyl-(10
glucopyranosyl-(10
glucopyranoside (16)
D
-glucopyranosyl-(10
3)-b-
-glucopyranosyl-(10
6)]-b-
-glucopyranosyl-(10
/
3)-[b-
D
-
3.77 (ABq, J 14.8 Hz, 2 H, ClCH2CO), 2.10 (s, 3 H,
MeCO), 2.08 (s, 3 H, MeCO), 2.08 (s, 3 H, MeCO), 2.02
(s, 3 H, MeCO). Anal. Calcd for C38H39Cl4NO18: C,
48.58; H, 4.18. Found: C, 48.43; H, 4.13.
/
D
/
3)-b-
D-
/
D
/
3)-a-D-
Compound 15 (320 mg, 0.14 mmol) was dissolved in a
satd solution of NH3 in MeOH (10 mL). After 2 weeks
at rt, the reaction mixture was concentrated, and the
residue was purified on a Bio-Gel P2 column with
3.11. 3-O-Allyl-2-O-benzoyl-4,6-O-benzylidene-D-
glucopyranosyl trichloroacetimidate (22)
3-O-Allyl-D
-glucopyranose16 (3.85 g, 17.5 mmol) was
MeOHꢁ
as a pulverous crystalloid: [a]D
NMR (400 MHz, D2O): d 5.86 (m, 1 H, CH2ꢀ
CH2), 5.25 (dd, 1 H, J 1.4, 17.2 Hz, CH2ꢀCHꢁCH2),
5.15 (dd, 1 H, J 1.4, 10.2 Hz, CH2ꢀCHꢁCH2), 4.86 (1
/
water as the eluent to afford 16 (138 mg, 96%)
36.68 (c 1.0, H2O); 1H
CH ꢁ
dissolved in DMF (50 mL), and then benzaldehyde (2.35
mL, 19.3 mmol), triethyl orthoformate (3.0 mL, 18.0
mmol) and toluenesulfonic acid (0.22 g, 1.16 mmol) were
added. The reaction mixture was stirred overnight at rt,
and then quenched with Et3N. The solution was
concentrated, and the residue was purified by chroma-
ꢀ
/
/
/
/
/
/
/
H, J1,2 3.6 Hz, H-1), 4.71 (1 H, J1,2 7.6 Hz, H-1), 4.69 (1
H, J1,2 8.0 Hz, H-1), 4.69 (1 H, J1,2 8.0 Hz, H-1), 4.60 (1
tography (1:1 petroleum etherꢁ/EtOAc) to give 3-O-
H, J1,2 8.0 Hz, H-1), 4.41 (1 H, J1,2 8.0 Hz, H-1), 4.11ꢁ
3.22 (m, 38 H, H-2ꢁ6, CH2ꢀCHꢁ
CH2); 13C NMR (100
MHz, D2O): d 132.7 (1 C, CH2ꢀCHꢁCH2), 118.4 (1 C,
CH2ꢀCHꢁCH2), 102.9, 102.9, 102.8, 102.7, 102.6, 97.2
(6 C-1, JC-1,H-1 163.2, 163.2, 165.1, 164.5, 164.3, 171.6
/
allyl-4,6-O-benzylidene-D-glucopyranose. The hemiace-
/
/
/
tal was dissolved in Py (20 mL), and benzoyl chloride (2
mL, 17.1 mmol) was added drop-wise. After 4 h at
20 8C, excess benzoyl chloride was destroyed with
MeOH, and the reaction mixture was concentrated.
The residue was taken up in CH2Cl2, washed with 0.2 M
HCl, 10% NaHCO3 and H2O, and then concentrated.
/
/
/
/
ꢄ
/
Hz), 84.3, 84.3, 84.1, 83.3, 76.1, 75.7, 75.6, 74.5, 74.1,
73.5, 73.3, 73.2, 73.1, 72.2, 71.7, 70.9, 70.7, 69.6, 69.0,
68.9, 68.5, 68.2, 67.8 (C-2ꢁ
signals overlapped). Anal. Calcd for C39H66O31: C,
45.44; H, 6.45. Found: C, 45.30; H, 6.41.
/
6, CH2ꢀ
/
CHꢁ
/
CH2, some
Crude
glucopyranose thus obtained was redissolved in a satd
solution of NH3 in 3:1 tolueneꢁMeOH (200 mL) and
stirred at rt until TLC (3:1 petroleum etherꢁEtOAc)
3-O-allyl-1,2-O-benzoyl-4,6-O-benzylidene-D-
/
/
3.10. 4,6-Di-O-acetyl-2-O-benzoyl-3-O-chloroacetyl-b-
3)-4,6-di-O-acetyl-2-O-benzoyl-a-
indicated that the reaction was complete. The solution
was concentrated, and the residue was purified by
D
-glucopyranosyl-(10
/
D-glucopyranosyl trichloroacetimidate (21)
chromatography with 3:1 petroleum etherꢁ
the eluent to give 3-O-allyl-2-O-benzoyl-4,6-O-benzyl-
idene- -glucopyranose. A mixture of the hemiacetal,
/
EtOAc as
Donor 17 (1.17 g, 1.98 mmol) and acceptor 18 (739 mg,
1.81 mmol) were coupled as described in the general
procedure. Purification of the product by chromatogra-
D
trichlorocetonitrile (3.2 mL, 15.0 mmol) and DBU (0.25
mL, 2.02 mmol) in dry CH2Cl2 (40 mL) was stirred at rt
for 3 h and then concentrated. The residue was purified
phy with 3:1 petroleum etherꢁEtOAc as the eluent
/

Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ
/
2366
2365
by flash chromatography (3:1 petroleum etherꢁ
to give 22 as an anomeric mixture (4.07 g, 42% for four
1
steps): H NMR (CDCl3): d 8.70 (s, 1 H, CNHCCl3),
/
EtOAc)
3.13. Methyl 2-O-benzoyl-4,6-O-benzylidene-b-
glucopyranosyl-(103)-2,4,6-tri-O-acetyl-b-
glucopyranoside (25)
D-
/
D-
8.59 (s, 1 H, CNHCCl3), 8.09ꢁ
Ph-H), 6.66 (d, 1 H, J1,2 3.6 Hz, a-H-1), 6.10 (d, 1 H, J1,2
7.8 Hz, b-H-1), 5.86 (m, 1 H, CH2ꢀCH ꢁCH2), 5.82 (m,
1 H, CH2ꢀCH ꢁCH2), 5.66 (s, 1 H, PhCH), 5.62 (s, 1 H,
PhCH), 5.57 (dd, 1 H, J1,2 J2,3 7.8 Hz, H-2), 5.39
(dd, 1 H, J1,2 3.6, J2,3 9.6 Hz, H-2), 5.28ꢁ5.06 (m, 4 H, 2
CH2ꢀCHꢁCH2), 4.46ꢁ3.81 (m, 12 H, 2 H-3, 2 H-4, 2 H-
5, H-6, CHꢁCH2). Anal. Calcd for
CH2ꢀ
/
7.40 (m, 20 H, 2 Bz-H, 2
Compound 24 (2.52 g, 85%) was obtained by coupling
of the donor 22 (2.77 g, 4.98 mmol) with the acceptor 23
(1.33 g, 4.16 mmol) as described in the general proce-
dure. A mixture of 24 (2.42 g, 3.39 mmol), PdCl2 (50 mg,
0.28 mmol), CH2Cl2 (60 mL), and CH3OH (30 mL) was
/
/
/
/
ꢄ
/
ꢄ
/
/
stirred at rt until TLC (2:1 petroleum etherꢁEtOAc)
/
/
/
/
suggested that the reaction was complete. Then the
mixture was filtered, the solution was concentrated to
dryness, and the residue was purified by flash chroma-
4
2
/
/
C25H24Cl3NO7: C, 53.93; H, 4.34. Found: C, 53.85; H,
4.24.
tography with 3:1 petroleum etherꢁ
to give 25 (2.10 g, 92%): [a]D
35.48 (c 1.0, CHCl3); 1H
NMR (CDCl3): d 8.00ꢁ7.26 (m, 10 H, Bz-H, Ph-H),
5.56 (s, 1 H, PhCH), 5.04 (dd, 1 H, J3,4 J4,5 8.8 Hz,
/EtOAc as the eluent
ꢃ
/
/
3.12. Methyl 2,4,6-tri-O-acetyl-b-D-glucopyranoside (23)
ꢄ
/
ꢄ
/
H-4), 5.02 (dd, 1 H, J1,2 7.4, J2,3 9.4 Hz, H-2?), 4.90 (dd,
1 H, J1,2 7.8, J2,3 8.8 Hz, H-2), 4.81 (d, 1 H, J1,2 7.4 Hz,
H-1?), 4.37 (dd, 1 H, J5,6?e 4.8, J6?e,6?a 10.2 Hz, H-6?e),
1,2,4,6-Tetra-O-acetyl-3-O-allyl-
g, 20.6 mmol)[16] was dissolved in a satd solution of
NH3 in 3:1 tolueneꢁMeOH (100 mL), and the mixture
was stirred at rt until TLC (3:1 petroleum etherꢁEtOAc)
indicated that the reaction was complete. The solution
was concentrated and purified by chromatography with
D-glucopyranose (8.00
/
4.28 (d, 1 H, J1,2 7.8 Hz, H-1), 4.30ꢁ
H-6e), 4.01 (dd, 1 H, J2,3 J3,4 9.4 Hz, H-3?), 4.96 (dd,
1 H, J2,3 J3,4 8.8 Hz, H-3), 3.75 (dd, 1 H, J3,4
J4,5 9.4 Hz, H-4?), 3.68ꢁ3.49 (m, 3 H, H-5, H-5?, H-
/
4.09 (m, 2 H, H-6?a,
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
/
6a), 3.38 (s, 1 H, CH3O), 2.07 (s, 3 H, MeCO), 2.04 (s, 3
H, MeCO), 1.91 (s, 3 H, MeCO). Anal. Calcd for
C33H38O15: C, 58.75; H, 5.64. Found: C, 58.63; H, 5.57.
3:1 petroleum etherꢁ
tri-O-acetyl-3-O-allyl-
2,4,6-tri-O-acetyl-3-O-allyl-
/
EtOAc as the eluent to give 2,4,6-
-glucopyranose. A mixture of
-glucopyranose, trichloro-
D
D
cetonitrile (5.6 mL, 26.2 mmol) and DBU (0.5 mL, 4.04
mmol) in dry CH2Cl2 (60 mL) was stirred at rt for 3 h
and then concentrated. The residue was purified by flash
3.14. Methyl 4,6-di-O-acetyl-2-O-benzoyl-3-O-
chloroacetyl-b-
2-O-benzoyl-b-
4,6-O-benzylidene-b-
O-acetyl-b- -glucopyranoside (26)
D
-glucopyranosyl-(10
-glucopyranosyl-(10
-glucopyranosyl-(10
/
3)-4,6-di-O-acetyl-
3)-2-O-benzoyl-
3)-2,4,6-tri-
chromatography (2:1 petroleum etherꢁ
the donor, 2,4,6-tri-O-acetyl-3-O-allyl-a-
/
EtOAc) to give
-glucopyra-
D
/
D
D
/
nosyl trichloroacetimidate (6.36 g, 63% for two steps).
The donor (6.4 g, 11.5 mmol) was coupled with MeOH
(5 mL) as described in the general procedure, and the
product was purified by flash chromatography (3:1
D
Coupling of the donor 21 (1.05 g, 1.12 mmol) with the
acceptor 25 (0.69 g, 1.02 mmol), followed by purifica-
petroleum etherꢁ
acetyl-3-O-allyl-b-
/
EtOAc) to give methyl 2,4,6-tri-O-
D-glucopyranoside. To a solution of
tion on a silica gel column with 1:1 petroleum etherꢁ
EtOAc as the eluent gave 26 as a foamy solid (888 mg,
60%): [a]D
13.48 (c 1.0, CHCl3); 1H NMR (CDCl3): d
8.06ꢁ7.26 (m, 20 H, 3 Bz-H, Ph-H), 5.48 (s, 1 H,
PhCH), 5.32 (dd, 1 H, J1,2 7.7, J2,3 9.6 Hz, H-2), 5.13ꢁ
5.06 (m, 4 H, 3 H-2, H-3), 4.97 (dd, 1 H, J3,4 J4,5 9.5
Hz, H-4), 4.92 (dd, 1 H, J3,4 J4,5 9.2 Hz, H-4), 4.88
(dd, 1 H, J3,4 J4,5 9.6 Hz, H-4), 4.69 (d, 1 H, J1,2 8.9
/
the methyl glucoside in 60 mL CH2Cl2 and 30 mL
CH3OH was added PdCl2 (100 mg, 0.56 mmol), and the
reaction mixture was stirred at rt until TLC (2:1
ꢃ
/
/
/
petroleum etherꢁEtOAc) suggested the reaction was
/
ꢄ
/
ꢄ
/
complete. Then the mixture was filtered, the solution
was concentrated to dryness, and the residue was
purified by flash chromatography (3:2 petroleum
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
Hz, H-1), 4.68 (d, 1 H, J1,2 7.4 Hz, H-1), 4.66 (d, 1 H,
J1,2 7.7 Hz, H-1), 4.35 (dd, 1 H, J5,6e 5.6, J6e,6a 13.9 Hz,
H-6e), 4.34 (dd, 1 H, J5,6e 5.3, J6e,6a 10.1 Hz, H-6e), 4.18
etherꢁ
a foamy solid: [a]D
(CDCl3): d 4.96 (dd, 1 H, J3,4
/
EtOAc) to give 23 (2.64 g, 62% for two steps) as
1
ꢀ
/
45.28 (c 1.0, CHCl3); H NMR
ꢄ
/
J4,5 9.7 Hz, H-4), 4.85
ꢄ
/
(d, 1 H, J1,2 7.7 Hz, H-1), 4.22ꢁ
6), 3.92 (dd, 1 H, J2,3 J3,4 9.1 Hz, H-3), 3.84 (dd, 1
H, J2,3 J3,4 8.9 Hz, H-3), 3.78, 3.72 (ABq, 2 H, J
15.2 Hz, ClCH2CO), 3.64 (dd, 1 H, J3,4 J4,5 9.1 Hz,
H-4), 3.61ꢁ3.35 (m, 4 H, 4 H-5), 3.30 (s, 3 H, CH3O),
/3.97 (m, 7 H, H-3, 6 H-
(dd, 1 H, J1,2 7.8, J2,3 9.6 Hz, H-2), 4.37 (d, 1 H, J1,2 7.8
Hz, H-1), 4.29 (dd, 1 H, J5,6?e 4.8 Hz, J6?e,6?a 12.3 Hz, H-
6?e), 4.16 (dd, 1 H, J5,6?a 4.8, J6?e,6?a 12.2 Hz, H-6?e), 4.11
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
ꢄ
/
(dd, 1 H, J2,3
ꢄ/J3,4
ꢄ9.7 Hz, H-3), 3.72 (ddd, 1 H, J4,5
/
/
9.7, J5,6?e 4.8, J5,6?a 3.4 Hz, H-5), 3.51 (s, 3 H, OCH3).
Anal. Calcd for C13H20O9: C, 48.75; H, 6.29. Found: C,
48.64; H, 6.20.
2.05 (s, 3 H, MeCO), 2.02 (s, 3 H, MeCO), 1.97 (s, 3 H,
MeCO), 1.96 (s, 3 H, MeCO), 1.95 (s, 3 H, MeCO), 1.94
(s, 3 H, MeCO), 1.79 (s, 3 H, MeCO). Anal. Calcd for

2366
Y. Zeng, F. Kong / Carbohydrate Research 338 (2003) 2359ꢁ2366
/
C69H75ClO32: C, 57.08; H, 5.21. Found: C, 57.10; H,
5.19.
and by The National Natural Science Foundation of
China (Projects 39970864 and 30070815).
3.15. Methyl b-
glucopyranosyl-(10
glucopyranoside (29)
D
-glucopyranosyl-(10
/
3)-b-D-
/3)-b-
D
-glucopyranosyl-(10
/3)-b-D-
References
Thiourea (150 mg, 1.97 mmol) was added to a solution
(50 mL) of 26 (520 mg, 0.36 mmol) in 1:2 MeOH and
CH2Cl2, then the reaction mixture was refluxed for 17 h,
1. Bruneteau, M.; Fabre, I.; Perret, J.; Michel, G.; Ricci, P.;
Joseleau, J.; Kraus, J.; Schneider, M.; Blaschek, W.;
Franz, Gerhard Carbohydr. Res. 1988, 175, 137ꢁ
2. Johnson, J.; Kirkwood, S.; Misaki, A.; Nelson, T. E.;
Scalleti, J. D.; Smith, F. Chem. Ind. (Lond.) 1963, 820ꢁ
/143.
at the end of which time TLC (2:3 petroleum etherꢁ
/
EtOAc) indicated that the reaction was complete. The
mixture was concentrated to 1/5 of the original volume,
diluted with CH2Cl2, washed with satd aq NaHCO3 and
water, and the organic phase was dried and concen-
trated. Purification by column chromatography with 1:1
/
822.
3. Sone, Y.; Kakuta, M.; Misaki, A. Agric. Biol. Chem. 1978,
42, 417ꢁ
4. Bender, H.; Lehmann, J.; Wallenfels, K. Biochim. Biophys.
Acta 1959, 36, 1309ꢁ1316.
5. Yoshioka, Y.; Tabeta, R.; Saito, H.; Uehara, N.; Fu-
kuoka, F. Carbohydr. Res. 1985, 140, 93ꢁ100.
6. Yamada, H.; Kawaguchi, N.; Ohmori, T.; Takeshita, Y.;
Taneya, S.; Miyazaki, T. Carbohydr. Res. 1984, 125, 107ꢁ
/
425.
/
petroleum etherꢁ
mg, 85%). Compound 27 (380 mg, 0.28 mmol) was
added to 90% HOAcꢁH2O (20 mL), and the mixture
/
EtOAc as the eluent afforded 27 (420
/
/
was refluxed for 2 h, then concentrated, and co-
evaporated with toluene (10 mL) for three times.
Purification by column chromatography with 2:3 petro-
/
115.
7. Usui, T.; Iwasaki, Y.; Mizuno, T.; Tanaka, M.; Shinkai,
leum etherꢁEtOAc as the eluent gave compound 28 (312
/
K.; Arakawa, M. Carbohydr. Res. 1983, 115, 273ꢁ
8. He, H.; Yang, F.; Du, Y. Carbohydr. Res. 2002, 337,
1673ꢁ1678.
9. Yang, G.; Kong, F. Synlett 2000, 1423ꢁ
10. Amaya, T.; Tanaka, H.; Yamaguchi, T.; Shibuya, N.;
Takahashi, T. Tetrahedron Lett. 2001, 9191ꢁ9194.
11. Takeo, K.; Maki, K.; Wada, Y.; Kitamura, S. Carbohydr.
Res. 1993, 245, 81ꢁ96.
12. Verduyn, R.; Douwes, M.; Van der Klein, P. A. M.;
Mosinger, E. M.; Van der Marel, G. A.; Van Boom, J. H.
/280.
mg, 88%), which was dissolved in a satd solution of NH3
in MeOH (10 mL). After 2 weeks at rt, the reaction
mixture was concentrated, and the residue was purified
/
/1426.
on a Bio-Gel P2 column with MeOHꢁ
eluent to afford 29 (86.7 mg, 94%) as a pulverous
crystalloid: [a]D
2.68 (c 1.0, H2O); 1H NMR (400
/water as the
/
ꢃ
/
/
MHz, D2O): 4.69 (1 H, J1,2 8.4 Hz, H-1), 4.67 (1 H, J1,2
8.0 Hz, H-1), 4.65 (1 H, J1,2 8.0 Hz, H-1), 4.31 (1 H, J1,2
6, OCH3); 13C
¨
8.0 Hz, H-1), 3.85ꢁ
NMR (100 MHz, D2O): d 103.0, 102.8, 102.6, 102.5 (4
C-1, JC-1,H-1 165.1, 164.7, 165.3, 164.8 Hz), 84.5, 84.3,
84.1, 76.0, 75.6, 75.5, 73.5, 73.3, 73.2, 72.8, 69.6, 68.2,
68.1, 68.9, 60.7, 57.2 (C-2ꢁ6, OCH3, some signals
/
3.24 (m, 27 H, H-2ꢁ
/
Tetrahedron 1993, 49, 7301ꢁ
13. (a) Zeng, Y.; Ning, J.; Kong, F. Tetrahedron Lett. 2002,
3729ꢁ3733;
(b) Zeng, Y.; Ning, J.; Kong, F. Carbohydr. Res. 2003,
338, 307ꢁ311.
14. (a) Varga, Z.; Bajza, I.; Batta, G.; Lipta´k, A. Tetrahedron
Lett. 2002, 43, 3145ꢁ3148;
(b) Motawia, S. M.; Marcussen, J.; Moller, L. J. Carbo-
hydr. Chem. 1995, 14, 1279ꢁ1294.
15. Schmidt, R. R.; Kinzy, W. Adv. Carbohydr. Chem.
Biochem. 1994, 50, 21ꢁ125.
16. Peri, F.; Nicotra, F.; Leslie, C. P.; Micheli, F.; Seneci, P.;
Marchioro, C. J. Carbohydr. Chem. 2003, 22, 57ꢁ71.
/
7316.
ꢄ
/
/
/
/
overlapped). Anal. Calcd for C25H44O21: C, 44.12; H,
6.52. Found: C, 43.98; H, 6.48.
/
/
Acknowledgements
/
This work was supported by The Chinese Academy of
Sciences (Projects KJ952J1510 and KIP-RCEES9904)
/