Facile synthesis of 1-thio-β-lactoside clusters scaffolded onto p-methoxyphenyl, β-D-galactopyranoside, β-D-glucopyranoside, and lactoside

Article abstract of DOI:10.1016/S0008-6215(02)00094-0

The free-radical addition of 2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl-(1 →4)-2,3,6-tri-O-acetyl-1-thio-β-D-glucopyranose to the allyl ether functions of p-methoxyphenyl per-O-allyl-D-galactopyranoside, D-glucopyranoside, and lactoside provides a concise and effective route for synthesis of glycoside clusters, of use for exploring anti-metastatic activity.

Full text of DOI:10.1016/S0008-6215(02)00094-0

Carbohydrate Research 337 (2002) 977–981
www.elsevier.com/locate/carres
Facile synthesis of 1-thio-b-lactoside clusters scaffolded onto
p-methoxyphenyl, b-
D
-galactopyranoside, b- -glucopyranoside, and
D
lactoside
Xiang-Bao Meng, Lian-Dai Yang, Hui Li, Qing Li, Tie-Ming Cheng, Meng-Shen Cai,
Zhong-Jun Li*
Department of Chemical Biology, School of Pharmaceutical Science, National Research Laboratory of Natural and Biomimetic Drugs,
Peking Uni6ersity, Beijing 100083, China
Received 10 October 2001; accepted 26 March 2002
Abstract
The free-radical addition of 2,3,4,6-tetra-O-acetyl-b-
D
-galactopyranosyl-(1“4)-2,3,6-tri-O-acetyl-1-thio-b-
D-glucopyranose to
-galactopyranoside, -glucopyranoside, and lactoside provides a concise
the allyl ether functions of p-methoxyphenyl per-O-allyl-
D
D
and effective route for synthesis of glycoside clusters, of use for exploring anti-metastatic activity. © 2002 Elsevier Science Ltd.
All rights reserved.
Keywords: Free-radical addition; 1-Thio-b-lactoside; Glycocluster; Anti-metastasis
1. Introduction
reactions of thiols with allylic ethers, to explore their
anti-metastatic activity.
Tumor cell adhesion mediated by cell-surface carbo-
hydrates has been suggested to play a key step in tumor
cell
metastasis.
Carbohydrates
are
potential
2. Results and discussion
candidates1–5 for prevention of metastatic spread by
disrupting the requisite carbohydrate-initiated interac-
tions between tumor cells and other cells, such as
endothelial cells and platelets.6 To date, application of
such approaches have been frustrated by the inherent
low affinity of carbohydrate ligands for their protein
receptors. Because cell-surface carbohydrates typically
occur as clusters, a variety of multivalent carbohydrates
have been designed and prepared7 to exploit the so-
called ‘‘glycoside-cluster effect ’’,8,9 which apparently
constitutes the best strategy for overcoming the ‘‘weak
binding’’ problem.
Synthesis of 1-thiolactose (3).—To prepare 3, hepta-
O-acetyl-a-lactosyl bromide (1) was refluxed with
thiourea in acetone for 30 min (Scheme 1) but the
intermediate, the 2-thiopseudourea hydrobromide (2)
was much more difficult to crystallize than described.14
Instead, the solution was concentrated, and then chlo-
roform and a solution of sodium pyrosulfite in water
heated at 85 °C were added to the residue. The mixture
was boiled for 15 min to give the desired compound 3
in 57.8% yield in two steps and characterized by FTIR
(2565 cm−1, SH; 1747 cm−1, CO).15
Methyl b-lactoside can significantly reduce the for-
mation of lung tumor colonies in mice.5 To increase its
efficacy, multivalent b-lactosides have been synthesized
in Roy’s group.10–13 We have, therefore, prepared three
lactoside clusters (I, II, and III), by classical radical
Synthesis of p-methoxyphenyl per-O-allyl glycosides
(6, 9, and 12) (Scheme 2).—Compounds 4,16 7, and 10
were O-deacetylated to afford 5, 8, and 11 quantita-
tively. Compounds 5, 8, and 11 were treated with
sodium hydride in anhydrous N,N-dimethylformamide
(DMF) at room temperature for 15 min and then allyl
bromide was added dropwise to give the corresponding
compounds 6, 9, and 12, respectively, in good yield.
* Corresponding author. Fax: +86-10-62367134.
E-mail address: zjli@mail.bjmu.edu.cn (Z.-J. Li).
0008-6215/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(02)00094-0

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X.-B. Meng et al. / Carbohydrate Research 337 (2002) 977–981
Synthesis of the free lactoside cluster target compounds
indicated almost complete conversion into 13, 14, or 15
when the concentration of 6, 9, and 12 in the reaction
mixture was about 5 mM. At lower concentrations
‘‘under substitution’’ of 6, 9, and 12 occurs; if the
concentration of the reactants is too high, then the major
product of the reaction is the disulfide formed by
dimerization of two molecules of 3.18–20
The acetyl-protected compounds 13, 14, and 15 were
deacetylated to afford the deprotected clusters (I, II, and
III) almost quantitatively (Scheme 3).
(I, II, and III).—Free-radical additions were initiated
mostly by exposure to UV radiation or by the addition
of chemical initiators. The first case requires special
apparatus and undesirable byproducts were formed in
the second.17 We chose a peroxide (o-nitroperoxybenzoic
acid) as the chain-reaction initiator. The methanolic
reaction mixture was thoroughly degassed by a stream
of argon and then heated to the decomposition temper-
ature of the catalyst, and boiled under reflux for 8 h. TLC
Scheme 1. (a) Thiourea, acetone, reflux, 30 min. (b) Na2S2O5, CHC13–H2O, reflux, 30 min. 57.8% (two steps).
Scheme 2. (a) NaOCH3, CH3OH, ion-exchange resin (H+); (b) allyl bromide, NaH, DMF, rt.
Scheme 3. (a) CH3OH, Ar, o-nitroperoxybenzoic acid, reflux; (b) NaOCH3, CH3OH, ion-exchange resin (H+).

X.-B. Meng et al. / Carbohydrate Research 337 (2002) 977–981
979
1
p-Methoxyphenyl 2,3,4,6-tetra-O-allyl-i-
D
-galacto-
Structural characterizations of the clusters.—The H
NMR spectra of the clusters are characterized by a
number of overlapping peaks due to many magnetically
similar CH2 and CH groups on each molecule. Assign-
ment of the broad-band spectra (especially the sugar
ring) is very difficult. The decoupled 13C NMR spectra
pyranoside (6).—Compound 6 (5.62 g, 87.1%) was ob-
tained as white needles; mp 70–71 °C; [h]2D5 −23.0° (c
1
1.13, CHCl3); H NMR (CDCl3): l 6.99 (d, 2 H, J 9.0
Hz, C6H4OCH3), 6.79 (d, 2 H, J 9.0 Hz, C6H4OCH3),
5.99–5.85 (m, 4 H, CH2ꢀCHCH2O), 5.30–5.12 (m, 8
H, CH2ꢀCHCH2O), 4.74 (d, 1 H, J1,2 7.5 Hz, H-1),
4.42–4.00 (m, 8 H, CH2ꢀCHCH2O), 3.82 (m, 2 H, H-2,
H-3), 3.77 (s, 1 H, OCH3), 3.68 (m, 1 H, H-5) 3.60 (m,
2 H, H-6a,6b), 3.40 (dd, 1 H, J 3.3, J 6.3 Hz, H-4); 13C
NMR (CDCl3): l 155.2, 151.6 (C6H4OCH3), 135.5,
135.3, 135.0, 134.5 (CH2ꢀCHCH2O), 118.6, 117.2,
116.8, 116.6, 114.5 (C6H4OCH3, CH2ꢀCHCH2O), 103.2
(C-1), 81.2 (C-2), 79.0; 74.0, 73.9, 73.6, 73.3
(CH2ꢀCHCH2O), 72.5, 71.9, 68.5 (C-6), 55.7 (OCH3);
MALDITOF–MS: Calcd for C25H34O7: m/z 446.5.
Found: m/z [M+Na]+ 469.6, [M+K]+ 485.5. Anal.
Calcd for C25H34O7: C, 67.24; H, 6.67. Found: C, 67.16;
H, 6.50.
1
shared similar features of the H NMR spectra. Some
of the C signals were difficult to detect because of their
relatively small intensities in the higher molecular-
weight derivatives.
The elemental analyses of all compounds were in
good agreement with theory.
MALDITOF–MS is the best way to confirm if the
product assignment is correct. The spectra of 15 ob-
tained in the positive-ion mode indicated two peaks:
m/z 5250.8 and 5276.7, which are smaller than the
calculated value (5295.0). It was assumed that the rela-
tively high laser energy (0.56 mJ) promoted deacetyla-
tion in the presence of the acidic matrix
(2,5-dihydroxybenzoic acid) and water. The two peaks
(5250.8 and 5276.7) can be assigned as [M−Ac+2H]+
and [M−Ac+H+Na]+ within the scope of instru-
mental error.
p-Methoxyphenyl 2,3,4,6-tetra-O-allyl-i-D-glucopy-
ranoside (9).—Compound 9 (4.00 g, 85.3%) was ob-
1
tained as a syrup; [h]2D5 −18.9° (c 2.65, CHCl3); H
NMR (CDCl3): l 6.99 (d, 2 H, J 9.0 Hz, C6H4OCH3),
6.80 (d, 2 H, J 9.0 Hz, C6H4OCH3), 6.02–5.85 (m, 4 H,
CH2ꢀCHCH2O), 5.32–5.15 (m, 8 H, CH2ꢀCHCH2O),
4.74 (d, 1 H, J1,2 7.2 Hz, H-1), 4.48–4.01 (m, 8 H,
CH2ꢀCHCH2O), 3.77 (s, 1 H, OCH3), 3.72 (m, 1 H,
H-2), 3.62 (dd, J 2.7, J 3.9 Hz, H-4), 3.45 (br, 4 H,
H-3,5,6a,6b); 13C NMR (CDCl3): l 155.3, 151.6
(C6H4OCH3), 135.2, 135.0, 134.8, 134.7 (CH2ꢀ
CHCH2O), 118.4 (2 C), 116.9, 116.7, 116.6, 114.5
(C6H4OCH3, CH2ꢀCHCH2O), 102.7 (C-1), 84.1, 81.4;
75.0, 74.4, 73.8, 73.7 (CH2ꢀCHCH2O), 72.4, 68.9 (C-6),
55.6 (OCH3); MALDITOF–MS: Calcd for C25H34O7:
m/z 446.5. Found: m/z [M+Na]+ 469.6, [M+K]+
485.5. Anal. Calcd for C25H34O7: C, 67.24; H, 6.67.
Found: C, 67.40; H, 6.45.
The anti-metastatic activity of these clusters on tu-
mor cells will be reported in detail elsewhere.
3. Experimental
General methods.—Solvents were purified conven-
tionally. Melting points are uncorrected. NMR spectra
were recorded with Varian VXR-300 and Jeol-300 spec-
trometers. Mass spectra were recorded with an LDI-
1700 spectrometer (MALDITOF). Optical rotations
were measured using an Optical Activity AA-10R auto-
matic polarimeter. Elemental analyses were performed
with a Perkin–Elmer 240C instrument. TLC was per-
formed on Silica gel GF254 plates (Hai Yang Chemical
Factory, Qingdao, Shandong, PR China) with detection
by quenching of UV fluorescence and by spraying with
5% H2SO4. Column chromatography was performed on
Silica Gel H (10–40 mm, Hai Yang Chemical Factory,
Qingdao, Shandong, PR China).
Typical methods for preparation of compounds 6, 9,
and 12.—To a solution of 5, 8, or 11 in anhyd DMF,
NaH (60%) was added (1.2 equiv per OH). The mixture
was stirred at rt for 15 min, and then allyl bromide (1.5
equiv per OH) was added dropwise. The reaction was
completed after 2 h, as indicated by TLC. Drops of
MeOH were added to decompose excess NaH, and then
the mixture was diluted with toluene and washed with
brine. The extracts were dried (Na2SO4) and evaporated
in vacuo, and the residue chromatographed to give the
desired 6, 9, and 12 in good yields.
p-Methoxyphenyl
2,3,6,2%,3%,4%,6%-hepta-O-allyl-i-
lactoside (12).—Compound 12 (5.97 g, 79.1%) was
obtained as white needles; mp 75–76 °C; [h]2D5 −19.6°
1
(c 1.43, CHCl3); H NMR (CDCl3): l 6.99 (d, 2 H, J
9.0 Hz, C6H4OCH3), 6.79 (d,
2 H, J 9.0 Hz,
C6H4OCH3), 6.02–5.84 (m, 8 H, CH2ꢀCHCH2O),
5.34–5.10 (m, 16 H, CH2ꢀCHCH2O), 4.74 (d, 1 H, J1,2
7.8 Hz, H-1), 4.48–3.95 (m, 16 H, CH2ꢀCHCH2O),
3.78 (m, 4 H), 3.76 (s, 3 H, OCH3), 3.64–3.44 (m, 8 H,),
3.30 (dd, 1 H, J 3.3, J 3.0 Hz, H-4); 13C NMR (CDCl3):
l 155.2, 151.8 (C6H4OCH3), 136.0, 135.7, 135.4, 135.3,
135.0, 134.6 (CH2ꢀCHCH2O), 118.5, 117.2, 116.6,
116.4, 116.0, 115.8, 114.5 (C6H4OCH3, CH2ꢀ
CHCH2O), 103.1, 102.7 (C-1,1%), 83.1, 82.1, 81.3, 79.5;
75.3, 74.3, 73.9, 73.8, 73.7, 73.1, 72.9, 71.5
(CH2ꢀCHCH2O), 68.5, 68.0 (C-6,6%), 55.7 (OCH3);
MALDITOF–MS: Calcd for C40H56O12: m/z 728.9.
Found: m/z [M+Na]+ 750.9, [M+K]+ 767.4. Anal.
Calcd for C40H56O12: C, 65.92; H, 7.74. Found: C,
65.76; H, 7.56.

980
X.-B. Meng et al. / Carbohydrate Research 337 (2002) 977–981
p-Methoxyphenyl 2,3,6,2%,3%,4%,6%-hepta-O-[3-(hepta-
O-acetyl-i-lactosylthio)propyl]-i-lactoside (15).—
Typical method for preparation of clusters 13, 14, and
15.—The thiol 3 (2 equiv per allyl group) and 6 (9 or
12, all at 5 mM) were dissolved in abs MeOH. A stream
of Ar was bubbled through the solution for 30 min to
thoroughly degas it. The solution, kept under an atmo-
sphere of Ar, was treated with o-nitroperoxybenzoic
acid (0.1 equiv per allyl group) under reflux until the
reaction was complete (8 h). The mixture was diluted
with EtOAc, washed with aq NaHCO3, dried (Na2SO4),
and concentrated. The residue was purified by column
chromatography to afford the product.
Compound 15 (220 mg, 46.5%) was obtained as a foam;
1
[h]2D5 +8.2° (c 0.98, CHCl3); H NMR (CDCl3): l 6.93
(d, 2 H, J 9.0 Hz, C6H4OCH3), 6.79 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 5.31 (m), 5.17–4.87 (m), 4.47 (br), 4.06
(br), 3.87 (br), 3.64 (br) (ꢀ112 H), 3.75 (s, 3 H,
OCH3), 3.48 (br, 14 H, OCH2CH2CH2S), 2.68 (br, 14
H, OCH2CH2CH2S), 2.12, 2.08, 2.02, 1.93, 1.81 (ꢀ147
H, Ac), 1.81 (br, 14 H, OCH2CH2CH2S); 13C NMR
(CDCl3): l 170.3, 170.1, 169.7, 169.1 (Ac), 155.2, 151.3,
118.0, 114.5 (C6H4OCH3), 101.0 (O-anomeric C), 83.7
(S-anomeric C), 76.2, 73.8, 70.9, 70.6, 69.1, 66.6, 62.2,
60.7; 55.6 (OCH3), 30.0 (OCH2CH2CH2S), 27.5
(OCH2CH2CH2S), 20.8, 20.6, 20.5 (Ac); MALDITOF–
MS: Calcd for C222H308O131S7: m/z 5295.0. Found: m/z
[M−Ac+2H]+5250.8, [M−Ac+H+Na]+ 5276.7.
Anal. Calcd for C222H308O131S7: C, 50.36; H, 5.86.
Found: C, 50.20; H, 5.65.
Typical method for the preparation of O-deprotected
clusters I, II, and III.—To a solution of 13 (14 or 15) in
abs MeOH, a catalytic amount of NaOCH3 was added.
The mixture was stirred at rt for 5 h, and then water
was added until the cloudy solution became clear again.
The solution was neutralized with cation-exchange resin
(H+). The resin was filtered off and washed with water,
and the combined filtrate and washings were evapo-
rated in vacuo to afford the target clusters quantita-
tively as white foams.
p-Methoxyphenyl 2,3,4,6-tetra-O-[3-(hepta-O-acetyl-
i-lactosylthio)propyl]-i-
D
-galactopyranoside
(13).—
Compound 13 (180 mg, 58.8%) was obtained as a foam;
1
[h]2D5 −7.5° (c 3.48, CHCl3); H NMR (CDCl3): l 6.93
(d, 2 H, J 9.0 Hz, C6H4OCH3), 6.79 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 5.31 (m, 4 H), 5.17–4.84 (m, 16 H), 4.43
(m, 14 H), 4.04 (m, 14 H), 3.85–3.77, 3.72–3.58 (m, 15
H), 3.74 (s,
3
H, OCH3), 3.52 (br,
8
H,
OCH2CH2CH2S), 2.67 (br, 8 H, OCH2CH2CH2S), 2.13,
2.11, 2.07, 2.06, 2.05, 2.04, 2.02, 2.01, 1.93 (ꢀ84 H,
Ac), 1.82 (br, 8 H, OCH2CH2CH2S); 13C NMR
(CDCl3): l 170.7, 170.6, 170.5, 170.4, 170.0, 169.4 (Ac),
155.5, 151.8, 118.4, 114.9 (C6H4OCH3), 101.5 (O-
anomeric C), 84.2, 77.8, 77.6 (S-anomeric C) 74.2, 71.8,
71.0, 70.9, 70.8, 69.5, 67.0, 62.6, 61.1; 56.0 (OCH3),
31.3, 30.8, 30.0 (OCH2CH2CH2S), 27.8, 27.7
(OCH2CH2CH2S), 21.3, 21.2, 21.1, 21.0, 20.1 (Ac);
p-Methoxyphenyl 2,3,4,6-tetra-O-[3-(i-lactosylthio)-
MALDITOF–MS: Calcd for
C129H178O75S4: m/z
-galactopyranoside (I).—[h]2D5 +93.7° (c
3055.7. Found: m/z [M+Na]+ 3074.6, [M+K]+
3091.1. Anal. Calcd for C129H178O75S4: C, 50.68; H,
5.87. Found: C, 50.96; H, 5.58.
propyl]-i-
D
1
1.26, D2O); H NMR (D2O): l 6.92 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 6.82 (d, 2 H, J 9.0 Hz, C6H4OCH3), 4.39
(m, 2 H), 4.26 (m, 6 H), 3.74 (s, 3 H, OCH3), 3.64–3.34
(m, ꢀ55 H), 3.19 (m, 8 H, OCH2CH2CH2S), 2.64 (br,
8 H, OCH2CH2CH2S), 1.79 (br, 8 H, OCH2CH2CH2S);
p-Methoxyphenyl 2,3,4,6-tetra-O-[3-(hepta-O-acetyl-
i-lactosylthio)propyl]-i-
D
-glucopyranoside
(14).—
Compound 14 (200 mg, 65.4%) was obtained as a foam;
[h]2D5 −21.1° (c 0.38, CHCl3); 1H NMR (CDCl3): l 6.93
(d, 2 H, J 9.0 Hz, C6H4OCH3), 6.80 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 5.32 (m, 4 H), 5.21–4.88 (m, 16 H), 4.45
(m, 14 H), 4.05 (m, 14 H), 3.86 (br), 3.63 (m, 15 H),
3.75 (s, 3 H, OCH3), 3.52 (br, 8 H, CH2CH2CH2S), 2.69
(br, 8 H, CH2CH2CH2S), 2.32, 2.14, 2.12, 2.08, 2.05,
2.03, 2.02, 2.00, 1.94 (ꢀ84 H, Ac), 1.82 (br, 8 H,
CH2CH2CH2S); 13C NMR (CDCl3): l 170.3, 170.1,
170.0, 169.9, 169.7, 169.1 (Ac), 155.2, 151.3, 118.0,
114.5 (C6H4OCH3), 101.1 (O-anomeric C), 84.7, 83.8,
83.6, 83.5, 82.0 (S-anomeric C), 77.9, 77.2, 76.2, 76.0,
73.8, 71.6, 71.1, 71.0, 70.9, 70.8, 70.6, 70.4, 70.1, 69.8,
69.7, 69.6, 69.0, 66.6, 62.2, 60.7; 55.6 (OCH3), 30.5,
30.1, 29.7 (OCH2CH2CH2S), 27.6, 27.3, 27.1 (OCH2-
CH2CH2S), 21.0, 20.9, 20.8, 20.6, 20.5 (Ac); MALDI-
13C NMR (D2O):
l 157.3, 153.5, 120.7, 117.8
(C6H4OCH3), 105.5 (O-anomeric C), 88.0, 87.9, 86.3
(S-anomeric C), 81.3, 78.4, 78.0, 78.0, 76.4, 75.2, 75.1,
75.0, 74.7, 74.5, 74.4, 73.7, 73.6, 72.2, 72.0, 72.1, 71.4,
71.2, 63.7, 62.9, 62.8 (3 C), 62.5; 58.5 (OCH3), 32.9,
32.7, 32.6, 31.9 (OCH2CH2CH2S), 29.5 (2 C), 29.4 (2
C), 29.3 (OCH2CH2CH2S); MALDITOF–MS: Calcd
for C73H122O47S4: m/z 1878.6. Found: m/z [M+Na]+
1901.8. Anal. Calcd for C73H122O47S4: C, 46.67; H,
6.55. Found: C, 47.00; H, 6.88.
p-Methoxyphenyl 2,3,4,6-tetra-O-[3-(i-lactosylthio)-
propyl]-i-
D
-glucopyranoside (II).—[h]2D5 −100.0° (c
1
0.80, D2O); H NMR (D2O): l 6.92 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 6.82 (d, 2 H, J 9.0 Hz, C6H4OCH3), 4.40
(m, 2 H), 4.25 (br, 6 H), 3.74 (s, 3 H, OCH3), 3.65–3.34
(m, ꢀ55 H), 3.20 (br, 8 H, OCH2CH2CH2S), 2.67 (br,
8 H, OCH2CH2CH2S), 1.77 (br, 8 H, OCH2CH2CH2S);
TOF–MS: Calcd for
Found: m/z [M+Na]+ 3076.3. Anal. Calcd for
129H178O75S4: C, 50.68; H, 5.87. Found: C, 50.88; H,
5.74.
C129H178O75S4: m/z 3055.7.
13C NMR (D2O):
l 157.3, 153.6, 120.8, 117.8
C
(C6H4OCH3), 105.5 (O-anomeric C), 88.0 (S-anomeric
C), 81.6, 81.3, 81.0, 78.4, 78.0, 76.2, 75.2, 75.0, 74.7,

X.-B. Meng et al. / Carbohydrate Research 337 (2002) 977–981
981
74.2, 73.6, 72.2, 72.0, 71.5, 71.2, 63.7, 62.9, 62.5; 58.5
References
(OCH3), 32.6, 32.3, 32.0 (OCH2CH2CH2S), 29.4
(OCH2CH2CH2S); MALDITOF–MS: Calcd for
C73H122O47S4: m/z 1878.6. Found: m/z [M+Na]+
1901.2. Anal. Calcd for C73H122O47S4: C, 46.67; H,
6.55. Found: C, 46.44; H, 6.40.
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p-Methoxyphenyl 2,3,4,2%,3%,4%,6%-hepta-O-(3-i-lacto-
sylthio)propyl-i-lactoside (III).—[h]2D5 +106.0° (c 1.17,
D2O); 1H NMR (D2O): l 6.94 (d, 2 H, J 9.0 Hz,
C6H4OCH3), 6.82 (d, 2 H, J 9.0 Hz, C6H4OCH3), 4.40
(m, 4 H), 4.26 (br, 10 H), 3.74 (s, 3 H, OCH3),
3.97–3.33 (m, ꢀ98 H), 3.20 (br, 14 H,
OCH2CH2CH2S), 2.68 (br, 14 H, OCH2CH2CH2S),
1.78 (br, 8 H, OCH2CH2CH2S); 13C NMR (D2O): l
157.3, 153.6, 120.6, 117.8 (C6H4OCH3), 105.8 (O-
anomeric C), 91.9, 88.1, 88.0 (2 C) (S-anomeric C),
81.7, 81.3, 80.9, 78.5, 78.2, 78.0, 75.2, 74.8, 74.7, 73.9,
73.4, 71.2, 63.7, 63.0, 62.8, 62.6; 58.5 (OCH3), 32.9, 32.8
(OCH2CH2CH2S), 29.5 (OCH2CH2CH2S); MALDI-
TOF–MS: Calcd for C124H210O82S7: m/z 3235.0.
Found: m/z [M+Na]+ 3256.7. Anal. Calcd for
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Acknowledgements
This project was supported by the National Natural
Science Foundation of the PR China (NSCF) and a
grant from the Ministry of Science and Technology of
the PR China.
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