A convergent synthesis of trisaccharides with α-Neu5Ac-(2 → 3)-β-D- Gal-(1 → 4)-β-D-GlcNAc and α-Neu5Ac-(2 → 3)-β-D-Gal-(1 → 3)-α-D-GalNAc sequences

Article abstract of DOI:10.1016/S0008-6215(00)00080-X

The syntheses of three trisaccharides: α-Neu5Ac-(2 → 3)-β-D-Gal-(1 → 4)-β-D-GlcNAc → OMe, α-Neu5Ac-(2 → 3)-β-D-Gal6SO₃Na-(1 → 4)-β-D- GlcNAc → OMe, and α-Neu5Ac-(2 → 3)-β-D-Gal-(1 → 3)-α-D-GalNAc → OBn were accomplished by using either methyl (

Full text of DOI:10.1016/S0008-6215(00)00080-X

www.elsevier.nl/locate/carres
Carbohydrate Research 328 (2000) 147–163
A convergent synthesis of trisaccharides with
a-Neu5Ac-(2“3)-b-
D
-Gal-(1“4)-b-
D
-GlcNAc and
a-Neu5Ac-(2“3)-b- -Gal-(1“3)-a-
D
D
-GalNAc sequences
Jie Xia, James L. Alderfer, Conrad F. Piskorz, Robert D. Locke, Khushi L. Matta *
Molecular and Cellular Biophysics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo,
NY 14263, USA
Received 20 September 1999; accepted 3 March 2000
Abstract
The syntheses of three trisaccharides: a-Neu5Ac-(2“3)-b-
-Gal6SO3Na-(1“4)-b- -GlcNAc“OMe, and a-Neu5Ac-(2“3)-b-
plished by using either methyl (phenyl 5-acetamido - 4,7,8,9 - tetra - O - acetyl - 3,5 - dideoxy - 2 - thio - b -
galacto-2-nonulopyranoside)onate or methyl (phenyl N-acetyl-5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-
-glycero- -galacto-2-nonulopyranoside)onate as the sialyl donor. The N,N-diacetylamino sialyl donor appears to
D
-Gal-(1“4)-b-
D
-GlcNAc“OMe, a-Neu5Ac-(2“3)-b-
-GalNAc“OBn were accom-
- glycero -
D
D
D
-Gal-(1“3)-a-
D
D
D-
b-D
D
be more reactive than its parent acetamido sugar when allowed to react with an disaccharide acceptor under the same
glycosylation conditions. The trisaccharides, as well as the intermediate products, were fully characterized by 2D
1
DQF H–1H COSY and 2D ROESY spectroscopy. © 2000 Elsevier Science Ltd. All rights reserved.
Keywords: Convergent synthesis; 2D DQF-COSY; 2D ROESY; Sialyl donor; Trisaccharide
(2“3) to galactose, a-(2“6) to galactose,
N-acetylglucosamine or N-acetylgalac-
1. Introduction
tosamine, and a-(2“8) to NeuAc. Sialosides
[5] have been the subject of extensive research
because of their potential use as therapeutics,
and recent reviews describe various ap-
proaches to their synthesis [6]. In synthetic
carbohydrate chemistry stereoselective a-sialyl-
ation, which derives from sialic acid’s unique
structural features [7], is one of the most
difficult problems. Therefore, many synthetic
methods have been developed to solve these
problems. The most successful method uses a
directing auxiliary group (ꢀOH, ꢀSePh, ꢀSPh)
in the 3b-position of Neu5Ac [8]. Recently,
the N,N-acyl group of neuraminyl derivatives
were used to synthesize sialylated oligosaccha-
rides [9]. This prompted us to prepare the
Sialic acid (Neu5Ac) frequently terminates
the oligosaccharide chains of glycoproteins
and glycolipids that play a central role in
cell-surface recognition phenomena [1]. Cell-
surface sialosides serve as ligands for micro-
bial toxins [2], microbial adhesions that
mediate attachment to host cells [3], and
lectins that mediate intercellular recognition
[4]. Sialic acids are usually found in the termi-
nal positions of oligosaccharides, and the
most abundant of these linkages include a-
* Corresponding author. Tel.: +1-716-8452300; fax: +1-
716-8453458.
E-mail address: klmatta@yahoo.com (K.L. Matta).
0008-6215/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(00)00080-X

148
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
relatively inexpensive and the most widely
used sialic acid donor 9, which has been used
in our laboratory [10], and its corresponding
5-N,N-diacetyl neuraminyl derivative, 23, and
examine their properties as sialyl donors with
disaccharide acceptors 8 and 20 in the synthe-
ses of three target trisaccharides with the a-
(4,6 - O - benzylidene - i -
(1“3)-2-acetamido-2-deoxy-6-O-trimethyl-
acetyl-h- -galacopyranoside (20).—In order
D
- galactopyranosyl)-
D
to synthesize the target trisaccharide
molecules 1–3 (Fig. 1) the monosaccharide
donors 4 [11], 9 [12], 14, and 23; monosaccha-
ride acceptors 5 [13], and 15 [14], another
disaccharide acceptors 8, and 20 were pre-
pared (Fig. 2, Schemes 1–3). Having the req-
uisite glycosyl donor and glycosyl acceptors in
hand, attention was focused on regioselective
glycosylation in order to prepare the b-(1“4)-
linked disaccharide 6. Thus, Sn(II)Cl2ꢀAgOTf
[15] mediated regioselective glycosylation of
2,3,4,6 - tetra - O - acetyl - b - galactopyranosyl
fluoride with the 4-hydroxyl group of 5 in the
presence of 3-hydroxyl group opening was
first tried. Unfortunately, this protocol re-
sulted in only a modest yield of the b-(1“4)-
linked disaccharide 6 after a long reaction
time of 12 h at −15 to 25 °C. Attention was
Neu5Ac-(2“3)-b-
“OMe (1), a-Neu5Ac-(2“3)-b-
SO3Na)-(1“4)-b- -GlcNAc“OMe (2) and a-
Neu5Ac-(2“3)-b- -Gal-(1“3)-a- -GalNAc-
D
-Gal-(1“4)-b-
D
-GlcNAc-
D-Gal-(6-
D
D
D
“OBn (3) sequences, which are frequently
occurring constitutes of glycoproteins and gly-
colipids.
2. Results and discussion
Synthesis of disaccharide acceptors: methyl
(4,6 - O - benzylidene - i -
D
- galactopyranosyl)-
(1“4)-2-deoxy-2-phthalimido-6-O-trimethyl-
acetyl-i- -glucopyranoside (8) and benzyl
D
Fig. 1. Targets sialylated and/or sulfated trisaccharides 1–3.
Fig. 2. Key intermediates used in the synthesis of the target trisaccharide molecules.

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
149
Scheme 1. (a) NIS–TfOH, 4A-MS, CH2Cl2, −45 to −40 °C, 1 h, 75%; (b) CH3ONa–CH3OH (1 M), 1:1 CH2Cl2–CH3OH, pH
10, −10 to −5 °C, 20 min, 86%; (c) PhCH(OCH3)2, p-TsOH–CH3CN, rt, 12 h, 78%; (d) donor 9, NIS–TfOH, 3A-MS, 3:1
CH2Cl2–CH3CN, −45 to −40 °C, 2 h, 45%; (e) 1:1 pyridine–Ac2O, DMAP, rt, 12 h; (f) 60% HOAc, 60–65 °C, 4–6 h, 71%;
(g) LiI–pyridine, 120–125 °C, 6–8 h; (h) 1:4 NH2NH2·H2O–EtOH, 80–90 °C, 4–5 h, then, 1:1 pyridine–Ac2O, DMAP, rt, 12 h;
(i) CH3ONa–CH3OH (1 M), CH3OH, rt, 12 h, three steps 15%; (j) SO3·pyridine–pyridine, 0–5 °C, 12–16 h, 64%; (k)
LiI–pyridine, 120–125 °C, 6–8 h; (l) 1:4 NH2NH2·H2O–EtOH, 80–90 °C, 4–5 h, then, 1:1 pyridine–Ac2O, DMAP, rt, 12 h; (m)
CH3ONa–CH3OH (1 M), CH3OH–H2O, rt, 12 h, three steps, 36%.
tion of two-dimensional double-quantum
then turned to thioglycosides, which have at-
tracted considerable attention and have been
very successfully used in oligosaccharide syn-
thesis. Coupling of phenyl 3,4,6-tetra-O-ace-
1
filtered H–1H correlation spectroscopy (2D
1
DQF H–1H COSY) and D2O exchange ex-
periments. The value observed for the vicinal
coupling constant (3J1,2) between the proton
on H-1% (doublet at l 4.62) and H-2% (double
doublet at l 5.23) associated with galactose
residue was 8.0 Hz, which confirmed the 1,2-
trans configuration (b configuration) of the
newly formed linkage. Intersaccharide connec-
tivity, e.g., the b-(1“4) linkage, was unam-
biguously confirmed by identification of a
doublet at l 4.26 which had a long range
coupling (3J=1.6 Hz) with H-3 of the Glc-
tyl-1-thio-b- -galactopyranoside (4) with
D
glycosyl acceptor 5 in the presence of the more
powerful activator NIS–TfOH at a reasonable
reaction temperature (−45 to −40 °C) gave
the desired b-(1“4)-linked disaccharide 6 in
excellent yield (75%).
The position, connectivity and stereochem-
istry of the glycosidic linkage in disaccharide 6
was fully confirmed by complete assignment
of all the peaks in the spectra with combina-

150
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
benzene afforded the desired b-(1“3)-linked
disaccharide 16 [16]. The disaccharide 17 was
obtained by treatment of disaccharide 16 with
60% HOAc at 60–65 °C for 1.5 h in an excel-
lent yield of 71%. Regioselective protection of
the primary hydroxyl group of disaccharide 17
was accomplished by treatment with pivaloyl
chloride in the presence of dry pyridine at
0–25 °C to give disaccharide 18 in a high yield
of 95%. The O-acetyl groups of disaccharide
18 were selectively removed in the presence of
the 6-O-pivaloyl substituent, as described for
the conversion to 7 from 6, providing com-
pound 19 in 99%. The 4,6-O-benzylidenated
disaccharide acceptor 20 was then obtained in
good yield (73%). Having the requisite glyco-
syl disaccharide acceptors 8 and 20 and the
sialyl donors 9 and 23 in hand, our attention
NPthth residue I as the proton from HO-3 of
1
the same sugar residue I in 2D DQF H–1H
COSY spectroscopy (not shown). This assign-
ment was further confirmed by treating disac-
charide 6 with D2O, which caused the doublet
peak at l 4.26 (HO-3) to disappear (Fig. 3).
Selective O-deacetylation of disaccharide 6
in 1:1 CH3OH–CH2Cl2 with 1 M sodium
methoxide solution at −10 to −5 °C for 20
min provided compound 7 in 86%. The 4,6-O-
benzylidenated disaccharide acceptor 8 was
then obtained in 78% yield by treatment of
compound 7 with a,a-dimethoxytoluene at
room temperature in dry acetonitrile and in
the presence of a catalytic amount of p-TsOH.
Condensation of compound 15 with galac-
tosyl bromide 14 (2.0 equivalents) (Scheme 2)
in the presence of Hg(CN)2 in 1:1 CH3NO2–
Scheme 2. (a) 1:1 Hg(CN)2–CH3NO2–benzene, 40–45 °C, 16–24 h; (b) 60% HOAc, 60–65 °C, 71%; (c) PivCl–pyridine, 0–25 °C,
12 h, 95%; (d) CH3ONa–CH3OH (1 M), pH 10, −10 to −5 °C, 20 min, 99%; (e) PhCH(OCH3)2, p-TsOH, CH3CN, rt, 3–4 h,
73%; (f) donor 9, NIS–TfOH, 3:1 CH2Cl2–CH3CN, 3A-MS, N2, −45 to −40 °C, 2–3 h, 42%; (g) 1:1 Ac2O–pyridine, DMAP,
rt, 12 h, 78%; (h) LiI–pyridine, 120–125 °C, 6–8 h, (i) 60% HOAc, 60–65 °C; (j) CH3ONa–CH3OH (1 M), CH3OH, rt, 24 h,
three steps, 52%.

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
151
NIS–TfOH in dry 3:1 dichloromethane–ace-
tonitrile for 1 h at −40 to −45 °C. Forma-
tion of the undesirable glycal was also
observed. An attempt was made to avoid for-
mation of the undesirable glycal by reducing
donor excess and using 1.1 equivalent of sialyl
donor 23. The disaccharide acceptor 8, how-
ever, was not completely consumed, and for-
mation of the undesirable glycal could not be
avoided. In order to completely consume dis-
accharide acceptor 8, another 1.1 equivalents
of sialyl donor 23 was added. In comparing
sialyl donors 9 and 23 in an identical reaction
with 8, the trivial additional N-acetyl group
seemingly improved reactivity of glycosyl
donor 23 (Scheme 3). Employment of a non-
polar (CH2Cl2), or polar (CH3CN, CH3-
CH2CN, ClCH2CH2Cl) solvent did not appear
to be critical to formation of the thermody-
namically unfavored a-glycoside of Neu5Ac
[9c,19]. A mixture of dichloromethane and
acetonitrile was used to accommodate the re-
spective solubilities of donors 9 and 23, as well
as acceptors 8 and 20. The proportion of
TfOH was found to be very critical for the
reaction, and 22–45% of TfOH to the amount
of NIS was deemed essential.
Scheme 3. (a) 2-Propenyl acetate–p-TsOH·H2O, 65 °C, 16 h,
99%; (b) donor 23, NIS–TfOH, 3:1 CH2Cl2–CH3CN, 3A-
MS, −45 to −40 °C, 1–1.5 h, 52–55%; (c) pyridine–Ac2O,
rt, 12 h, 78%; (d) LiI–pyridine, 120–125 °C, N2, 6–8 h, (e)
60% HOAc, 60–65 °C, 4–6 h; (f) 4:1 EtOH–NH2–NH2·H2O,
80–85 °C, 6 h, then, Ac2O–pyridine, rt, 12 h, (g) CH3ONa–
CH3OH (1 M), CH3OH, rt, 24 h, four steps, 12%.
was next focused on their regioselective and
stereoselective sialylation.
The complete structural assignment for
compounds 10, 22 and 24 was accomplished
Regio- and h-stereoselecti6e sialylation of
disaccharide acceptors 8 and 20 with sialyl
donors 9 and 23.—Phenylthio-containing sia-
lyl donors 9 and 23 were employed along with
N-iodosuccinimide (NIS)–trifluoromethane-
sulfonic acid (TfOH), a powerful glycosyl pro-
moter for thioglycosides [17] and n-pentenyl
glycosides [18]. Regioselective sialylation of
HO-3 of the galactose residue of disaccharide
acceptors 8 and 20 was achieved because of its
higher nucleophilicity as compared to HO-2.
Thus, 8 and 20, respectively, were reacted with
sialyl donor 9 (2.20–3.0 equivalents) in 3:1
dichloromethane–acetonitrile for 2 h at −40
to −45 °C promoted by NIS–TfOH to yield
trisaccharides 10 (45%) and 21 (42%)
(Schemes 1 and 2). The undesired glycal, a
product of elimination of sialyl donor 9, was
observed as a major product. Similarly, trisac-
charide 24 was obtained in 50–55% yield from
reaction of 8 with new sialyl donor 23 (2.2–
3.0 equivalents) (Scheme 3) in the presence of
1
through a combination of 2D DQF H–1H
COSY spectroscopy (Fig. 4: 1D and Fig. 5:
2D DQF-COSY spectra of trisaccharide 24)
and 2D ROESY spectroscopy (not shown).
The stereochemistry of the glycosidic linkage
for Neu5Ac in trisaccharides 10, 22 and 24,
was determined to be the a configuration,
based on the chemical shifts of H-4¦ and H-7¦
that were observed at l 5.00–4.90 (H-4¦) and
l 5.32–5.27 (H-7¦) for trisaccharide 10, at
4.85–4.80 (H-4¦) and 5.37–5.23 (H-7¦) for 22
[20] and similar shifts for trisaccharide 24. The
chemical shift of H-4¦ for trisaccharide 24 was
downfield at l 5.48–5.40 because of the elec-
tron-withdrawing effect of an additional N-
acetyl group, while that for H-7¦ was at l
5.23–5.17. The connectivity of a-Neu5Ac-
(2“3)-b-
D
-Gal-(1“4)-b- -GlcN of trisac-
D
charide 25 was confirmed by 2D ROESY
spectroscopy by observation of a strong NOE
cross-peak between H-1% (l 4.73–4.71) of

152
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
Remo6al of protecti6e groups to produce
target trisaccharides h-Neu5Ac-(2“3)-i-
Gal-(1“4)-i- -GlcNAc-(1“O)Me (1), h-
Neu5Ac-(2“3)-i- -Gal-(6-SO3Na)-(1“4)-
i- -GlcNAc-(1“O)Me (2) and h-Neu5Ac-
(2“3)-i- -Gal-(1“3)-h- -GalNAc(1“O)-
Bn (3).—Trisaccharide 1 was obtained from
sugar residue II and H-4 (l 3.84) of sugar
residue I, confirming a b- -Gal-(1“4)-Glc-
NAc linkage. A similar observation of a weak
NOE cross-peak between H-3% (l 4.53–4.50)
of sugar residue II and H-3a¦ (l 1.67–1.61) of
sialic acid residue III confirmed the Neu5Ac-
(2“3)-Gal linkage.
D
-
D
D
D
D
D
D
1
Fig. 3. 400 MHz H NMR spectra of disaccharide 6: (A) recorded in CD2Cl2; (B) recorded in CD2Cl2+D2O at 303.0 K.
1
Fig. 4. 400 MHz H NMR spectrum of trisaccharide 24 recorded in CD2Cl2 at 303.0 K.

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
153
1
Fig. 5. 600 MHz 2D H–1H DQF-COSY spectrum of trisaccharide 24 recorded in CD2Cl2 at 303.0 K.
spectrum of 1, a weak intersaccharide NOE
cross peak was observed between H-3a¦ (l
1.739–1.730) of sialic acid residue III and
H-3%(l 4.09–4.02) of galactose residue II,
which is indicative that the sialic acid residue
was attached to C-3 of galactose residue II.
Similarly, a strong NOE cross peak between
H-1% (at l 4.44–4.42) to H-4 (at l 3.60–3.58)
of sugar residue I (see Figs. 6 and 7) indicated
linkage at C-4 of GlcNAc.
11 by; (a) removal of the 4,6-O-benzylidene
group of 11 by treatment with 60% aqueous
HOAc at 60–65 °C to give 12; (b) removal of
methyl group by treatment of compound 12 in
the presence of a large excess of lithium iodide
in dry pyridine at 120–125 °C under dry N2,
(c) removal of the phthalimido group (EtOH–
NH2NH2·H2O, 80–90°C, 4 h), then acetyla-
tion with pyridine–Ac2O, (d) O-deacetylation
(NaOCH3–CH3OH). A protocol employed
for preparation of target trisaccharide 2 was
similar to that described in the literature [10c].
A similar deprotection procedure was adopted
for trisaccharide 22 to afford the target trisac-
charide 3.
The structures of trisaccharide 1, 2, and 3
were unambiguously established by a combi-
nation of 2D DQF 1H–1H COSY spec-
troscopy, 2D ROESY spectroscopy and 13C
NMR experiments. For example, in the NMR
Fig. 6. NOEs of inter- and intrasaccharide residues indicated
by the 2D ROESY spectrum.

154
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
Fig. 7. NOEs of inter- and intrasaccharide residues observed by 2D ROESY spectra.
In summary, the glycosylating capability of
CD2Cl2, CD3OD. 13C NMR spectra were
recorded at 303.0 K with a Bruker AM 400
(100.6 MHz) spectrometer using CDCl3 (77.0
ppm), CD2Cl2 (54.15 ppm), CD3OD (49.15
ppm), or acetone-d6 (206.0 or 29.8) as refer-
ence. First-order chemical shifts and coupling
constants (J/Hz) were obtained from one-di-
mensional spectra, and assignments of protons
sialyl donor 23 was compared with that of its
derivative 9 by synthesizing three target trisac-
charides,
Gal-(1“4)-b-
Neu5Ac-(2“3)-b-
GlcNAc-(1“O)-Me (2) and a-Neu5Ac-
-GalNAc-(1“O)-
namely,
-GlcNAc-(1“O)-Me (1), a-
-Gal6-SO3Na-(1“4)-b-
a-Neu5Ac-(2“3)-b-
D
-
D
D
D
-
(2“3)-b-
D
-Gal-(1“3)-a-
D
1
resonance were based on 2D DQF H–1H
Bn (3). The presence of an additional N-acetyl
group apparently improved the reactivity of
sialyl donor 23 in comparison to that of its
parent compound 9.
COSY and 2D ROESY. Two-dimensional
1
double-quantum filtered phase sensitive H–
1
1H correlated spectra (DQF H–1H COSY)
and rotating-frame nuclear Overhauser en-
hancement spectroscopy (ROESY) were
recorded at 303.0 K using a Bruker AM 400
(400 MHz) spectrometer and a Bruker AMX
600 (600 MHz) spectrometer. For ROESY
experiments, the mixing time was set at 400
ms. All samples submitted for elemental
analyses were dried for 48 h under vacuum
over P2O5 at room temperature (rt). Elemental
analyses were performed by Robertson Labo-
ratory, Madison, NJ. p-Toluenesulfonic acid
monohydrate (p-TsOH·H2O) was co-evapo-
rated (at 80 °C) with anhyd MeCN, then dried
3. Experimental
General
procedures.—Thin-layer
chro-
matography (TLC) was conducted on glass
plates precoated with a 0.25 mm layer of Silica
Gel 60 F254 (Analtech GHLF uniplates). The
components were visualized either by expo-
sure to UV light or by spraying with 10%
H2SO4, and 0.2% p-anisaldehyde in a solution
of EtOH and heating or both. Solutions were
concentrated under reduced pressure at B
40 °C. The silica gel used for column chro-
matography was Baker Analyzed (60–200
mesh). Optical rotations were measured at
25 °C with a Perkin–Elmer 241 polarimeter.
1H NMR spectra were recorded at 30 °C with
either a Bruker AM 400 (400 MHz) or AMX
600 (600 MHz) spectrometer. The values of l
(ppm) are given relative to the signal (l 0) for
internal Me4Si for solutions in CDCl3,
under vacuum for 0.5
h
before use.
CH2Cl2,CH3CN, CH3OH, and benzene were
,
kept over 4 A molecule sieves. Pyridine was
redistilled over potassium hydroxide, and
CH3NO2 was freshly distilled over P2O5.
Pheny1 2,3,4,6-tetra-O-acetyl-1-thio-i- -
D
galactopyranoside (4).—Compound 4 was pre-
pared according to the literature [11] in
quantitative yield as a white solid: TLC Rf =

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
155
was then neutralized with satd aq NaHCO3,
the solids were filtered off, and the organic
layer was washed with satd NaHCO3 soln,
Na2S2O3 (10%) and water, dried with Na2SO4
and concentrated. The crude product was
purified on a silica gel column using 1:1 hex-
ane–EtOAc as the eluent to give pure com-
pound 6 (13.08 g, 75%) as an amorphous
solid: TLC Rf =0.43 (1:1 hexane–EtOAc);
[h]D +14.7° (c 1.0, CHCl3); 1H NMR
(CD2Cl2, 400 MHz): l 7.90–7.82 (m, 2 H,
ArH), 7.80–7.74 (m, 2 H, ArH), 5.40–5.36 (d,
1 H, J3%,4% 3.2 Hz, H-4%), 5.26–5.20 (dd, 1 H,
J2%,1% 8.4, J2%,3% 10.4 Hz, H-2%), 5.18–5.12 (d, 1
H, J1,2 8.4 Hz, H-1), 5.04–4.98 (dd, 1 H, J3%,4%
3.6, J2%,3% 11.0 Hz, H-3%), 4.64–4.60 (d, 1 H,
J1%,2% 8.0 Hz, H-1%), 4.42–4.38 (m, 2 H, H-3,
H-6a), 4.24–4.22 (d, 1 H, J 1.6 Hz, OH-3),
4.18–4.00 (m, 5 H, H-2, H-6b, H-5%, H-6a%,
H-6b%), 3.82–3.74 (m, 1 H, H-5), 3.60–3.56
(dd, 1 H, H-4), 3.41 (s, 3 H, OCH3), 2.14 (s, 3
H, Ac), 2.08 (s, 3 H, Ac), 1.97 (s, 3 H, Ac),
1.83 (s, 3 H, Ac), 1.26 (s, 9 H, t-Bu); 13C
NMR (CD2Cl2, 100.6 MHz): l 177.76, 170.38,
170.23, 170.06, 169.61, 134.36, 132.05, 123.4,
102.31, 99.40 (C-1, C-1%), 83.97, 72.41, 71.80,
71.99, 70.07, 68.90, 67.14, 62.97, 61.97, 55.85,
56.07, 27.26 (3 CH3), 20.66 (Ac), 20.58 (Ac),
20.52 (Ac), 20.29 (Ac); Anal. Calcd for
C34H43NO17: C, 55.36; H, 5.89; N, 1.90.
Found: C, 55.47; H, 5.95; N, 1.83.
0.43 (4:1 hexane–EtOAc); [h]D +12.0° (c 1.5,
CHCl3); 1H NMR (CDCl3, 400 MHz): l
7.50–7.40 (m, 2 H, ArH), 7.32–7.20 (m, 3 H,
ArH), 5.40–5.30 (d, 1 H, J 2.8 Hz, H-4),
5.20–5.10 (t, 1 H, H-2), 5.10–4.90 (dd, 1 H,
J3,4 2.8, J2,3 8.0 Hz, H-3), 4.70–4.60 (d, 1 H,
J1,2 9.6 Hz, H-1), 4.20–4.10 (m, 2 H, H-6a,
H-6b), 4.00–3.80 (t, 1 H, H-5), 2.05 (s, 3 H,
Ac), 2.03 (s, 3 H, Ac), 1.98 (s, 3 H, Ac), 1.91
(s, 3 H, Ac); 13C NMR (CDCl3, 100.6 MHz):
l 132.67, 128.98 128.22, 86.57 (C-1), 74.55,
72.10, 67.41, 61.77, 62.00, 20.93 (Ac), 20.73
(Ac), 20.67 (Ac), 20.63 (Ac).
Methyl 2 - deoxy - 6 - O - trimethylacetyl - 2-
phthalimido-i- -glucopyranoside (5).—To a
D
cold (0 °C), stirred solution of methyl 2-
deoxy - 2 - phthalimido - b - - glucopyranoside
D
(25.34 g, 78.45 mmol) in dry pyridine (150
mL), was added trimethylacetyl chloride (11
mL, 86.30 mmol). After 9 h at rt, an addi-
tional portion (4 mL, 31.38 mmol) of
trimethylacetyl chloride was added again, and
stirring was continued for a total of 21 h. The
solution was concentrated, and the crude mix-
ture was applied to a column of silica gel and
eluted with 20:1 CH2Cl2–CH3OH to give pure
compound 5 (30 g, 95%) as an amorphous
solid: TLC Rf=0.45 (20:1 CH2Cl2–CH3OH);
1H NMR (CDCl3, 400 MHz): l 7.82–7.81 (m,
2 H, ArH), 7.75–7.71 (m, 2 H, ArH), 5.09–
5.07 (d, 1 H, J1,2 8.8 Hz, H-1), 4.46–4.44 (dd,
1 H, H-6a), 4.38 (m, 2 H, H-6b, H-3), 4.03–
3.98 (dd, 1 H, H-2), 3.64–3.61 (m, 1 H, H-4),
3.41–3.36 (m, 4 H, OCH3, H-5), 1.25 (s, 9 H,
t-Bu); 13C NMR (CDCl3, 100.6 MHz): l
179.19, 133.90, 131.56, 123.27, 99.03 (C-1),
73.91, 73.75, 71.89, 71.32, 63.20, 56.41, 27.00
(3 CH3).
Methyl
(i- -galactopyranosyl)-(1“4)-2-
D
deoxy-6-O-trimethylacetyl-2-phthalimido-i-
D-
glucopyranoside (7).—To a cold (−10 to
−5 °C) solution of compound 6 (5.0 g, 6.78
mmol) in 1:1 CH2Cl2 –CH3OH (30 mL), was
added dropwise a 1 M soln of CH3ONa in
MeOH until the pH of the soln was adjusted
to 10, and the stirring was continued at the
same temperature for 20 min. The solution
was then neutralized with Amberlite IR 120
(H+) cation-exchange resin, filtered and con-
centrated. The crude product was applied to a
short column of silica gel eluted with 10:1
CH2Cl2–CH3OH to give pure compound 7
(3.31 g, 86%) as an amorphous solid: TLC
Methyl (2,3,4,6-tetra-O-acetyl-i-
topyranosyl)-(1“4)-2-deoxy-6-O-trimethyl-
acetyl - 2 - phthalimido - i - - glucopyranoside
D-galac-
D
(6).—A solution of pheny1 2,3,4,6-tetra-O-
acetyl-1-thio-b-galactopyranoside (4, 12.86 g,
29.23 mmol), methyl 2-deoxy-2-phthalimido-
6-O-trimethylacetyl-b- -glucopyranoside (5,
D
13.08 g, 32.14 mmol), NIS (19.72 g, 87.69
mmol) in dry CH2Cl2 (238 mL) containing
4A-MS (149 g) was stirred at −45 to −40 °C
for 2–3 h in an N2 atmosphere. TfOH (2.97
mL) was then added, and stirring continued at
the same temperature for 1 h. The solution
Rf =0.31 (10:1 CH2Cl2–CH3OH); [h]D
+
1
13.5° (c 0.5, CH3OH); H NMR (CD2Cl2, 400
MHz): l 8.00–7.60 (m, 4 H, ArH), 5.12–5.10
(d, 1 H, J1,2 8.0 Hz, H-1), 4.70–4.60 (dd, 1 H),
4.50–4.37 (m, 2 H), 4.34–4.32 (d, 1 H, J1%,2%

156
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
glucopyranoside (10).—A solution of donor 9
(1.109 g, 1.90 mmol), disaccharide acceptor 8
(500 mg, 0.76 mmol), NIS (1.28 g, 5.7 mmol)
in dry 3:1 CH2Cl2–MeCN (30 mL) containing
3A-MS (5 g) was cooled (−45 to −40 °C)
and stirred in an atmosphere of N2 for 1.5–2
h. TfOH (0.15 mL) was then added dropwise
and the stirring was continued at the same
temperature for 1.5 h. More TfOH (40 mL)
was then added, and stirring was continued
for an additional 1 h. The solution was neu-
tralized with satd aq NaHCO3 soln, the solids
were filtered off, and the organic layer was
washed with satd NaHCO3 soln, 10% Na2S2O3
and water, dried (Na2SO4) and concentrated.
The crude mixture was placed on a short silica
gel column and eluted with 1:5 hexane–
EtOAc to give pure compound 10 (430 mg,
0.380 mmol, 45%) as a glass white solid: TLC
Rf =0.35 (1:5 hexane–EtOAc); 1H NMR
(CDCl3, 400 MHz) l 8.00–7.90 (m, 2 H,
ArH), 7.90–7.80 (m, 2 H, ArH), 7.60–7.40
(m, 2 H, ArH), 7.40–7.20 (m, 3 H, ArH),
5.46–5.43 (m, 1 H, H-8¦), 5.37 (s, 1 H, benzyl-
idene proton), 5.32–5.27 (t, 2 H, H-7¦,
NHAc¦), 5.21–5.19 (d, 1 H, J1,2 8.8 Hz, H-1),
5.00–4.90 (ddd, 1 H, H-4¦), 4.85–4.82 (d, 1 H,
J 2.8 Hz, H-4%), 4.57–4.55 (d, 1 H, J1%,2% 8.0
Hz, H-1%), 4.48–4.44 (dd, 1 H, J 8.8, 10.8 Hz,
H-3), 4.41–4.38 (dd, 1 H, J 2.2, Jgem 12.6 Hz,
H-9b¦), 4.27–4.19 (m, 3 H, H-3%, H-6a, H-2),
4.16–4.04 (m, 4 H, H-6¦, H-6b%, H-9a¦, H-6b),
3.98–3.83 (m, 4 H, H-5¦, H-2%, H-5%, H-5),
3.68 (s, 3 H, COOCH3), 3.58–3.56 (m, 2 H,
H-6a%, H-4), 3.46 (s, 3 H, OCH3), 2.77–2.72
(dd, 1 H, J3e¦,4¦ 4.4, Jgem 12.6 Hz, H-3e¦), 2.13
(s, 3 H, Ac), 2.11 (s, 3 H, Ac), 2.02 (s, 3 H,
Ac), 2.00 (s, 3 H, Ac), 1.98 (s, 3 H, Ac), 1.97
(t, 1 H, J3a¦,3e¦ 12.6 Hz, H-3a¦), 1.25 (s, 9 H,
t-Bu); 13C NMR (CDCl3, 100.6 MHz) l
178.25, 171.07, 170.82, 170.46, 170.42, 170.33,
137.90, 134.12, 132.14, 129.19, 128.33, 126.58,
123.48, 104.49, 101.11, 99.24, 97.45 (C-1, C-1%,
C-2¦, benzylidene carbon), 83.27, 75.05, 73.99,
73.38, 72.86, 70.14, 68.94, 68.65, 68.59, 68.50,
67.30, 66.79, 63.54, 62.85, 56.80, 56.11, 53.20,
50.05, 38.56 (C-3¦), 27.43 (3 CH3) (Ac), 23.40
(Ac), 21.47 (Ac), 21.00 (Ac), 20.93 (Ac); Anal.
Calcd for C53H66N2O25: C, 56.28; H, 5.89; N,
2.48. Found: C, 55.95; H, 5.95; N, 2.40.
7.2 Hz, H-1%), 4.04–3.98 (dd, 1 H), 3.79–3.60
(m, 5 H), 3.60–3.50 (m, 2 H), 3.50–3.40 (dd,
1 H), 3.36 (s, 3 H, OCH3), 1.25 (s, 9 H, t-Bu);
13C NMR (CD2Cl2, 100.6 MHz) l 180.14,
136.07, 133.39, 124.72, 105.71, 100.96 (C-1,
C-1%), 81.86, 77.85, 75.26, 74.93, 72.95, 71.52,
70.79, 64.41, 63.12, 58.08, 57.46, 40.4
[C(CH3)3], 27.95 (CH3); Anal. Calcd for
C26H35NO13: C, 54.83; H, 6.21; N, 2.46.
Found: C, 54.93; H, 6.21; N, 2.32.
Methyl (4,6-O-benzylidene-i-
ranosyl)-(1“4)-2-deoxy-6-O-trimethylacetyl-
2-phthalimido-i- -glucopyranoside (8).—To a
D
-galactopy-
D
solution of compound 7 (830 mg, 1.46 mmol),
a,a-dimethoxytoluene (0.5 mL, 2.3 mmol) in
dry MeCN (20 mL), was added p-TsOH·H2O
(191 mg). The mixture was stirred overnight at
rt. The acid was then neutralized with Et3N,
and the solution concentrated. The crude
product was applied to a short column of
silica gel eluted with 20:1 CH2Cl2–MeOH to
give pure compound 8 (752 mg, 78%) as an
amorphous solid: TLC Rf=0.44 (20:1
CH2Cl2 –CH3OH) [h]D +31.7° (c 1.0, CHCl3);
1H NMR (CD2Cl2, 400 MHz): l 7.90–7.80
(m, 2 H, ArH), 7.80–7.70 (m, 2 H, ArH),
7.50–7.40 (m, 2 H, ArH), 7.40–7.30 (m, 3 H,
ArH), 5.52 (s, 1 H, benzylidene proton), 5.15–
5.13 (d, 1 H, J1,2 8.4 Hz, H-1), 4.66–4.63 (dd,
1 H, J 1.6, Jgem 11.6 Hz, H-6a), 4.50–4.40 (dd,
1 H, H-3), 4.38–4.36 (d, 1 H, J1%,2% 8.2 Hz,
H-1%), 4.30–4.20 (dd, 1 H, J 5.6, Jgem 12.0 Hz,
H-6b), 4.20–4.10 (m, 2 H, H-4%, H-6a%), 4.10–
4.00 (m, 2 H, H-2, H-6b%), 3.80–3.70 (m, 2 H,
H-5, H-2%), 3.70–3.60 (m, 1 H, H-3%), 3.56 (m,
1 H, H-5%), 3.53–3.49 (t, 1 H, H-4), 3.41 (s, 3
H, OCH3), 3.30 (d, 1 H, J2%,OH% 2.8 Hz, OH-2%),
2.70 (d, 1 H, J3%,OH% 8.0 Hz, OH-3%), 1.24 (s, 9
H, t-Bu); 13C NMR (CD2Cl2, 100.6 MHz): l
138.05, 134.47, 132.17, 129.50, 128.55, 126.61,
123.58, 104.48, 101.50, 99.50 (C-1, C-1%, ben-
zylidene carbon), 83.12, 75.36, 73.67, 72.99,
71.81, 70.11, 69.14, 67.50, 63.55, 57.00, 56.20,
39.80 [C(CH3)3], 27.36 (3 CH3); Anal. Calcd
for C33H39NO13: C, 60.27; H, 5.99; N, 2.13.
Found: C, 60.02; H, 6.15; N, 1.89.
Methyl [methyl (5-acetamido-4,7,8,9-tetra-
O-acetyl-3,5-dideoxy-
D
-glycero-h- -galacto-
D
non - 2 - ulopyranosyl)onate] - (2“3) - (4,6-O-
benzylidene-i- -galactopyranosyl)-(1“4)-2-
deoxy-2-phthalimido-6-O-trimethylacetyl-i-
D
Methyl [methyl (5-acetamido-4,7,8,9-tetra-
D
-
O-acetyl-3,5-dideoxy-
D
-glycero-h- -galacto-
D

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
157
non-2-ulopyranosyl)onate]-(2“3)-(2-O-acetyl-
i- -galactopyranosyl)-(1“4)-2-deoxy-3-O-
acetyl-2-phthalimido-6-O-trimethylacetyl-i-
perature for 9 h. The solution was then
quenched with MeOH and concentrated. The
crude mixture was placed on a short silica gel
column and eluted with 10:1 CH2Cl2–MeOH
to give compound 13 (150 mg, 64%) as a white
glass solid: TLC Rf =0.16 (10:1 CH2Cl2–
D
D-
glucopyranoside (12).—Compound 10 (380
mg, 0.30 mmol) was acetylated with 1:1
Ac2O–pyridine in the presence of a catalytic
amount of DMAP at rt overnight, and the
acetylated product of 10 was treated with 60%
aq AcOH (20 mL) at 60–65 °C for 6 h. The
solution was then concentrated. The crude
product was purified in a short column of
silica gel with 10:1 CH2Cl2–MeOH as the
eluent to give compound 12 (220 mg, 71%) as
an amorphous solid: TLC Rf=0.40 (10:1
1
CH3OH); H NMR (CD3OD, 400 MHz): l
8.00–7.90 (m, 4 H, ArH), 5.76–5.69 (ddd, 1
H, H-8¦), 5.67–5.63 (dd, 1 H, J 8.4, J 10.8 Hz,
H-3), 5.40–5.37 (d, 1 H), 5.29–5.27 (d, 1 H,
J1,2 8.4 Hz, H-1), 5.05–5.01 (dd, 1 H, J 8.0, J
9.8 Hz, H-2), 4.80–4.78 (d, 1 H, J1%,2% 7.2 Hz,
H-1%), 4.69–4.66 (d, 1 H, J 9.6 Hz), 4.30–4.29
(m, 2 H), 4.22–4.17 (dd, 1 H), 4.10–3.90 (m,
9 H), 3.84 (s, 3 H, OCH3), 3.76–3.74 (t, 1 H,
H-5), 3.58–3.57 (d, 1 H, J 2.4 Hz, H-4%), 3.41
(s, 3 H, OCH3), 2.75–2.71 (dd, 1 H, J 4.0, Jgem
12.2 Hz, H-3e¦), 2.31 (s, 3 H, Ac), 2.17 (s, 3
H, Ac), 2.07 (s, 6 H, 2 Ac), 1.98 (s, 3 H, Ac),
1.95 (s, 3 H, Ac), 1.82 (s, 3 H, Ac), 1.68–1.60
(t, 1 H, Jgem 12.8 Hz, H-3a¦), 1.26 (s, 9 H,
t-Bu); 13C NMR (CD3OD, 100.6 MHz) l
174.16, 172.96, 172.84, 172.77, 170.18, 136.40,
125.03, 103.24, 100.64 (C-1, C-1%), 99.18 (C-
2¦), 79.32, 75.53, 75.21, 74.78, 73.80, 73.55,
71.93, 71.57, 69.55, 69.28, 68.39, 66.82, 64.69,
64.45, 57.73, 56.87, 54.43, 50.61, 39.43 (C-3¦),
28.27 (3 CH3), 23.34 (Ac), 22.39 (Ac), 22.28
(Ac), 21.66 (Ac), 21.54 (Ac), 21.41 (Ac); Anal.
Calcd for C50H66N2O30S: C, 49.75; H, 5.51; N,
2.32; S, 2.66. Found: C, 49.77; H, 5.41; N,
2.12; S, 2.66.
1
CH2Cl2 –CH3OH); H NMR (CD3OD, 400
MHz): l 8.00–7.80 (m, 2 H, ArH), 7.80–7.60
(m, 2 H, ArH), 5.72–5.68 (dd, 1 H, J 8.4, J
10.4 Hz, H-3), 5.56–5.50 (m 2 H), 5.24–5.22
(d, 1 H, J1,2 8.0 Hz, H-1), 5.21–5.19 (d, 1 H),
5.00–4.98 (t, 1 H), 4.96–4.93 (ddd, 1 H, H-
8¦), 4.67–4.65 (d, 1 H, J1%,2% 7.6 Hz, H-1%),
4.59–4.56 (d, 1 H, Jgem 11.6 Hz, H-9b¦), 4.40–
4.36 (dd, 1 H, J 2.4, J 12.4 Hz, H-6a), 4.310–
4.29 (dd, 1 H, J 2.4, J 10.2 Hz), 4.15–3.72 (m
11 H, OCH3), 3.57 (d, 1 H, H-4%), 3.50–3.49
(t, 1 H, H-5), 3.99 (s, 3 H, OCH3), 2.67–2.63
(dd, 1 H, J 4.4, Jgem 11.0 Hz, H-3e¦), 2.23 (s,
3 H, Ac), 2.12 (s, 3 H, Ac), 2.08 (s, 3 H, Ac),
2.05 (s, 3 H, Ac), 2.00 (s, 3 H, Ac), 1.99 (s, 3
H, Ac), 1.92 (s, 3 H, Ac), 1.80–1.78 (t, 1 H,
Jgem 12.3 Hz, H-3a¦), 1.25 (s, 9 H, t-Bu); 13C
NMR (CD3OD, 100.6 MHz) l 173.71, 172.49,
172.38, 172.24, 172.14, 171.95, 171.36, 169.86,
135.86, 124.62, 102.73, 102.20 (C-1, C-1%),
98.68 (C-2¦), 78.61, 76.55, 75.41, 74.77, 73.47,
73.10, 71.60, 71.12, 69.13, 68.79, 68.24, 64.17,
63.95, 61.42, 57.32, 56.45, 53.72, 50.18, 40.2
[C(CH3)3], 39.04 (C-3¦), 27.83 (3 CH3), 22.91
(Ac), 21.97 (Ac), 21.82 (Ac), 21.23 (Ac), 21.09
(Ac), 21.00 (Ac), 20.82 (Ac); Anal. Calcd for
C50H66N2O27: C, 53.28; H, 5.90; N, 2.48.
Found: C, 53.46; H, 5.92; N, 2.39.
Methyl [(5-acetamido-3,5-dideoxy-
ero-h- -galacto-non-2-ulopyranosylonic acid)-
(2“3)-i- -galactopyranosyl]-(1“4)-2-aceta-
mido-2-deoxy-i- -glucopyranoside (1).—
D-glyc-
D
D
D
Lithium iodide (LiI, 400 mg, 3.0 mmol) was
added to a solution of compound 12 (170 mg,
0.15 mmol) in dry pyridine (3 mL), The mix-
ture was stirred for 6–8 h at 120–125 °C
under an N2 atmosphere. The dark-yellow
solution was concentrated, and the residue
was co-evaporated with toluene, then dis-
solved in EtOAc. The solution was washed
with satd NaCl, dried (Na2SO4), and evapo-
rated to a bright-yellow residue that was di-
rectly used for the next step. To the solution
of the bright-yellow free acid in MeOH (15
mL) was added NH2NH2·H2O (5 mL) solu-
tion. After 3–4 h at 80–85 °C, the mixture
was concentrated under vacuum to a crude
mixture that was co-evaporated with toluene,
Methyl [methyl (5-acetamido-4,7,8,9-tetra-
O-acetyl-3,5-dideoxy-
D
-glycero-h- -galacto-
D
non-2-ulopyranosyl)onate]-(2“3)-(6-O-sulfate-
i - - galactopyranosyl) - (1“4) - 2 - deoxy - 2-
phthalimido-6-O-trimethylacetyl-i- -glucopy-
D
D
ranoside (13).—To a cold (0–5 °C) stirred so-
lution of compound 12 (220 mg, 0.19 mmol)
in dry pyridine (3 mL) was added a
SO3·pyridine complex (36 mg, 0.23 mmol),
and stirring was continued at the same tem-

158
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
mmol) and powdered Hg(CN)2 (2.8 g) in 1:1
benzene–nitromethane (100 mL) was boiled
until 50 mL of solvent had distilled off. The
temperature was then adjusted to 40–45 °C,
then acetylated with 1:1 Ac2O–pyridine (8
mL) overnight at rt. The acetylated mixture
was concentrated and de-acetylated with 1 M
CH3ONa in MeOH at rt for 24 h and concen-
trated under vacuum to give a crude mixture
that was purified on a short silica gel column
by eluting with 3:1:1 n-C3H7OH–HOAc–wa-
ter to give compound 1 (16.0 mg, 15%) as an
amorphous solid: TLC Rf =0.30 (3:1:1 n-
and 2,4,6-tetra-O-acetyl-a- -galactopyranosyl
D
bromide (3.83 g, 9.34 mmol) was added, and
the stirring was continued for 16–24 h at
40–45 °C. The mixture was diluted with ben-
zene and washed with satd aq NaHCO3, 10%
aq potassium iodide and water, dried
(Na2SO4), and concentrated. The crude mix-
ture was taken up in 60% aq AcOH (20 mL)
and stirred for 1.5–2 h at 60–65 °C. The
AcOH was evaporated under reduced pres-
sure, and the residue was co-evaporated with
several added portions of toluene. It was then
applied to a short column of silica gel and
eluted with 20:1 CH2Cl2–CH3OH to give pure
compound 17 (2.37 g, 71%) as a bright-yellow
glassy solid: TLC Rf=0.41 (20:1 CH2Cl2–
1
C3H7OH–HOAc–water); H NMR (CD3OD,
600 MHz): l 4.44–4.42 (d, 1 H, J1,2 7.8 Hz,
H-1%), 4.30–4.28 (d, 1 H, J1,2 8.4 Hz, H-1),
4.04–4.03 (dd, 1 H, J 2.4, J 8.4 Hz, H-3%),
3.92–3.82 (m, 5 H, H-6b%, H-4%, H-6a%, H-4,
H-9b¦), 3.73–3.67 (m, 4 H, H-7¦, H-4¦, H-2,
H-6b), 3.65–3.52 (m, 6 H, H-3, H-6¦, H-9a¦,
H-6a, H-2, H-5¦), 3.48–3.47 (m, 1 H, H-5),
3.44 (s, 3 H, OCH3), 3.40–3.39 (m, 2 H, H-8¦,
H-5%), 2.85–2.83 (dd, 1 H, J 4.0, Jgem 10.8 Hz,
H-3e¦), 1.99 (s, 3 H, Ac), 1.94 (s, 3 H, Ac),
1.71 (t, 1 H, H-3a¦); 13C NMR (CD3OD,
100.6 MHz) l 180.64 (CꢁO), 175.70 (CꢁO),
173.82 (CꢁO), 105.20, 104.07, 102.30 (C-1,
C-1%, C-2¦), 82.30, 77.84, 77.29, 76.76, 75.14,
74.51, 73.24, 71.08, 70.32, 69.55, 69.28, 64.87,
62.95, 62.20, 61.23, 57.25, 56.66, 54.20, 42.27
(C-3¦), 23.13 (Ac), 22.82 (Ac).
1
CH3OH); [h]D +84.3° (c 1.0, CHCl3); H
NMR (CD2Cl2, 400 MHz): l 7.37–7.36 (m, 5
H, ArH), 5.86–5.84 (d, 1 H, J 9.2 Hz, NHAc),
5.36–5.32 (d, 1 H, H-4%), 5.20–5.10 (t, 1 H,
H-2%), 5.10–5.00 (dd, 1 H, H-3%), 5.00–4.90 (d,
1 H, H-1), 4.72–4.69 (d, 1 H, Jgem 12.0 Hz,
OCHAPh, ABq), 4.67–4.65 (d, 1 H, J1%,2% 8.0
Hz, H-1%), 4.60–4.40 (m, 2 H, OCHBPh, Jgem
11.2 Hz, ABq), 4.20–4.00 (m, 3 H), 4.00–3.90
(m, 1 H), 3.90–3.80 (m, 4 H), 2.13 (s, 3 H,
Ac), 2.02 (s, 3 H, Ac), 1.95 (s, 3 H, Ac), 1.92
(s, 3 H, Ac), 1.90 (s, 3 H, Ac); 13C NMR
(CDCl3, 100.6 MHz) l 172.88, 172.03, 171.89,
171.57, 171.47, 135.30, 129.59, 129.47, 128.98,
102.84, 97.98 (C-1, C-1%), 78.37, 72.46, 72.29,
72.01, 70.30, 69.95, 68.88, 49.73, 22.89 (Ac),
20.84 (Ac), 20.65 (Ac), 20.57 (2 Ac); Anal.
Calcd for C29H39NO15: C, 54.29; H, 6.14; N,
2.18. Found: C, 54.09; H, 6.13; N, 2.12.
Methyl
cero-h- -galacto-non-2-ulopyranosylonic acid)-
(2“3)-(sodium 6-O-sulfo-i- -galactopyrano-
syl]-(1“4)-2-acetamido-2-deoxy-i- -gluco-
[(5-acetamido-3,5-dideoxy- -gly-
D
D
D
D
pyranoside (2).—Compound 13 (100 mg, 0.08
mmol) was submitted to an identical reaction
sequence as described for 12 to give 1. The
residue dissolved in water and stirred with
Amberlite IR 120 cation exchange resin (Na+)
for 4–5 h at rt. The resin was filtered off, the
filtrate was concentrated and purified on a
column of silica gel by eluting with 1:1:1
n-C3H7OH–HOAc–water to give compound
2 (25 mg, 36%) as a amorphous solid: TLC
Rf=0.42 (1:1:1 n-C3H7OH–HOAc–H2O); 13C
NMR (D2O, 100.6 MHz) l 173.99, 173.37,
172.78, 101.43, 99.85, 98.81, 77.34, 72.29,
66.14, 61.60, 59.66, 56.05, 54.04, 50.68, 38.63
(C-3¦), 21.11, 21.02.
Benzyl (2,3,4,6-O-tetra-O-acety-i-
topyranosyl)-(1“3)-2-acetamido-2-deoxy-6-
O - trimethylacetyl - h - - galacopyranoside
D-galac-
D
(18).—To a cold (ice-bath) soln of compound
17 (1.96 g, 3.06 mmol) in dry pyridine (20 mL)
was added dropwise trimethylacetyl chloride
(0.41 mL, 3.33 mmol), and the stirring was
continued for 8 h at 0–25 °C. More trimethyl-
acetyl chloride (0.12 mL) was added at 0 °C,
and the stirring was continued for an addi-
tional 4–5 h at 0–25 °C. The mixture was
concentrated, and the crude product was
Benzyl (2,3,4,6-O-tetra-O-acetyl-i-
topyranosyl)-(1“3)-2-acetamido-2-deoxy-h-
-galacopyranoside (17).—A stirred mixture
of benzyl 2-acetamido-4,6-O-benzylidene-2-
deoxy-a- -galactopyranoside (15, 2.08 g, 5.21
D-galac-
D
D

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
159
compound 20 (1.31 g, 73%) as a white solid:
TLC Rf=0.5 (10:1 CH2Cl2–MeOH); 1H
NMR (CD2Cl2, 400 MHz): l 7.56–7.50 (m, 2
H, ArH), 7.40–7.30 (m, 8 H, ArH), 5.60–5.50
(s, 1 H, benzylidene proton), 5.00 (d, 1 H, J1,2
4.0 Hz, H-1), 4.80–4.72 (d, 1 H, Jgem 12.0 Hz,
OCHAPh, ABq), 4.52–4.44 (m, 2 H, OCHBPh,
Jgem 11.2 Hz, ABq, H-2), 4.44–4.40 (d, 1 H,
J1,2 7.6 Hz, H-1%), 4.32–4.28 (m, 3 H, H-6a,
H-6b%, H-6b), 4.24–4.16 (m, 2 H, H-4, H-4%),
4.16–4.08 (m, 2 H, H-5, H-6a%), 3.92–3.84
(dd, 1 H, J 2.8, J 11.2 Hz, H-3), 3.72–3.64
(dd, 1 H, H-2%), 3.64–3.56 (dd, 1 H, H-3%),
1.96 (s, 3 H, Ac), 1.23 (s, 9 H, t-Bu); 13C
NMR (CD2Cl2, 100.6 MHz): l 129.40, 128.87,
128.55, 128.49, 128.41, 126.61, 105.67, 101.54,
97.38 (C-1, C-1%, benzylidene carbon), 79.42,
76.35, 72.62, 71.12, 69.77 (2 C), 69.01 (2 C),
67.26, 64.64, 39.80, 27.24 (3 CH3), 22.75 (Ac);
Anal. Calcd for C33H43NO12: C, 61.39; H,
6.71; N, 2.17. Found: C, 61.17; H, 6.75; N,
2.17.
passed through a short silica gel column and
eluted with 40:1 CH2Cl2–MeOH to give pure
compound 18 (2.1 g, 95%) as a white solid:
TLC Rf=0.28 (40:1 CH2Cl2–MeOH); [h]D +
1
76.0° (c 0.5, CHCl3); H NMR (CD2Cl2, 400
MHz): l 7.60–7.20 (m, 5 H, ArH), 5.53–5.51
(d, 1 H, J 9.6 Hz, NHAc), 5.40–5.39 (d, 1 H,
J3%,4% 2.8 Hz, H-4%), 5.23–5.20 (dd, 1 H, H-2%),
5.02–4.98 (dd, 1 H, H-3%), 4.97–4.96 (d, 1 H,
J1,2 3.6 Hz, H-1, a form), 4.76–4.73 (d, 1 H, J
11.2 Hz, OCHAPh, ABq), 4.64–4.60 (m, 2 H,
H-1%, J1%,2% 8.0 Hz, H-2), 4.48–4.45 (d, 1 H,
Jgem 12.0 Hz, OCHBPh, ABq), 4.41–4.36 (m, 2
H, H-6a%, H-6b%), 4.18–4.09 (m, 4 H, H-4,
H-6a, H-5%, H-6b), 4.00–3.92 (t, 1 H, H-5),
3.81–3.78 (dd, 1 H, H-3), 2.05 (s, 3 H, Ac),
2.04 (s, 3 H, Ac), 2.01 (s, 3 H, Ac), 1.98 (s, 3
H, Ac), 1.95 (s, 3 H, Ac), 1.24 (s, 9 H, t-Bu);
13C NMR (CD2Cl2, 100.6 MHz): l 178.52,
170.51, 170.36, 170.35, 169.55, 169.51, 137.03,
128.92, 128.68, 128.61, 128.34, 101.89, 97.21
(C-1, C-1%), 78.13, 71.13, 70.85, 69.73, 68.84,
68.77, 68.54, 68.48, 67.08, 64.27, 61.46, 27.42
(3 CH3), 23.55, 20.85, 20.83, 20.80, 20.75,
20.72; Anal. Calcd for C34H47NO16: C, 56.27;
H, 6.54; N, 1.93. Found: C, 56.38; H, 6.53; N,
1.90.
Benzyl [methyl (5-acetamido-4,7,8,9-tetra-
O-acetyl-3,5-dideoxy-
D
-glycero-h- -galacto-
D
non-2-ulopyranosyl)onate]-(2“3)-(2-O-acetyl-
4,6 - O - benzylidene - i - - galactopyranosyl)-
(1“4)-3-acetyl-6-O-trimethylacetyl-2-aceta-
mido-2-deoxy-h- -galactopyranoside (22).—A
D
D
Benzyl (4,6-O-benzylidene-i-
osyl) - (1“3) - 2 - acetamido - 6 - O - trimethyl-
acetyl-2-deoxy-h- -galactopyranoside (20).—
D-galactopyran-
solution of donor 9 (470 mg, 0.81 mmol),
disaccharide acceptor 20 (220 mg, 0.34 mmol),
NIS (547 mg, 2.43 mmol) in dry 3:1 CH2Cl2–
MeCN (30 mL) containing 3A-MS (6.0 g) was
stirred at −45 to −40 °C for 1.5–2 h in an
atmosphere of N2. TfOH (64 mL) was then
added dropwise, and the stirring was contin-
ued at the same temperature for 1.5 h. Addi-
tional TfOH (17 mL) was added, and stirring
was continued at the same temperature for 1
h. The mixture was neutralized with satd aq
NaHCO3, the solids were filtered off and the
organic layer was washed with satd NaHCO3
soln, 10% Na2S2O3, water, dried (Na2SO4),
and concen-trated under diminished pressure
to a crude mixture that was passed through a
short silica gel column eluted with 1:5 hex-
ane–EtOAc to give pure compound 21 (156
mg, 0.14 mmol, 42.0%) as an amorphous
solid. Compound 21 (370 mg, 0.33 mmol) was
treated with 1:1 pyridine–Ac2O (10 mL)
overnight at rt. The mixture was concentrated
under reduced pressure, and the residue was
passed through a short silica gel column
D
A solution of compound 18 (2.04 g, 2.81
mmol) in 1:1 CH2Cl2–MeOH (20 mL) was
cooled to −10 to −5 °C, treated with a 1 M
solution of CH3ONa–CH3OH until the pH of
the solution was equal to 10 (controlled by pH
paper), and the stirring was continued at the
same temperature for 20 min. The solution
was neutralized with Amberlite IR120 (H+)
cation-exchange resin. The resin was filtered
off, and the mixture was concentrated. The
crude product was applied to a short silica gel
column and eluted with 10:1 CH2Cl2–MeOH
to give quantitatively pure compound 19 (1.56
g, 2.80 mmol), which was dissolved in dry
CH3CN (48 mL) and a,a-dimethoxytoluene
(2.31 mL, 4.20 mmol), then treated with p-
TsOH (461 mg). After 6–8 h at rt the solution
was neutralized with Et3N and concentrated
to give a crude product mixture which was
passed through a short silica gel column
eluted with 10:1 CH2Cl2–MeOH to give pure

160
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
stirred at 60–65 °C for 4–6 h. The mixture
was then concentrated, and the residue was
dissolved in MeOH (5 mL) and treated with 1
M CH3ONa and stirred overnight at rt. It was
concentrated under reduced pressure, and the
crude product was passed through a short
silica gel column eluted with 3:1:1 n-
C3H7OH–HOAc–water to give compound 3
(53 mg, 52%) as an amorphous solid: TLC
Rf =0.46 (3:1:1 n-CH3CH2CH2OH–HOAc–
eluted with 20:1 CH2Cl2–CH3OH to give
compound 22 (310 mg, 78%) as an amorphous
solid: TLC Rf=0.64 (20:1 CH2Cl2–CH3OH);
[h]D +69.6° (c 1.65, CHCl3); 1H NMR
(CDCl3, 400 MHz): l 7.48–7.22 (m 10 H,
ArH), 6.50–6.49 (d, 1 H, J 6.0 Hz, NHAc),
5.70–5.60 (ddd, 1 H, H-8¦), 5.43–5.42 (d, 1 H,
J 2.8 Hz, H-4), 5.37–5.23 (m, 4 H, NHAc¦,
H-7¦, benzylidene proton, H-2%), 5.18–5.17 (d,
1 H, J1,2 3.6 Hz, H-1), 4.85–4.80 (ddd, 1 H,
H-4¦), 4.76–4.74 (d, 1 H, J1%,2% 8.0 Hz, H-1%),
4.63–4.60 (d, 1 H, Jgem 12.0 Hz, OCHAPh,
ABq), 4.46–4.43 (d, 1 H, Jgem 12.8 Hz,
OCHBPh, ABq), 4.42–4.36 (m, 3 H, H-2, H-
3%, H-9b¦), 4.27–4.11 (m, 3 H, H-6a, H-6a%,
H-6b%), 4.11–4.06 (m, 2 H, H-3, H-5¦), 4.00–
3.96 (m, 2 H, H-6b, H-5%), 3.91–3.84 (m, 2 H,
H-6¦, H-9a¦), 3.74 (s, 3 H, OCH3), 3.71–3.70
(d, 1 H, H-4%), 3.48 (m, 1 H, H-5), 2.67–2.65
(dd, 1 H, J 4.2 Hz, Jgem 12.8 Hz, H-3e¦), 2.24
(s, 3 H, Ac), 2.17 (s, 3 H, Ac), 2.10 (s, 6 H, 2
Ac), 2.00 (s, 3 H, Ac), 1.94 (s, 3 H, Ac), 1.87
(s, 3 H, Ac), 1.85 (s, 3 H, Ac), 1.79–1.72 (t, 1
1
water); [h]D +65.7° (c 0.25, CH3OH); H
NMR (CD3OD, 600 MHz): l 7.40–7.28 (m, 5
H, ArH), 4.91 (d, 1 H, H-1), 4.77–4.75 (d, 1
H, Jgem 12.0 Hz, OCHAPh, ABq), 4.52–4.99
(d, 1 H, Jgem 12.0 Hz, OCHBPh, ABq), 4.49–
4.47 (d, 1 H, J1%,2% 7.2 Hz, H-1%), 4.43–4.4.41
(dd, 1 H, J 9.6 Hz, H-2), 4.20 (s, 1 H, H-4),
4.04–4.02 (dd, 1 H, H-3%), 4.00–3.99 (t, 1 H,
H-3), 3.94 (d, 1 H, H-5), 3.90–3.83 (m, 1 H,
H-8¦), 3.82–3.60 (m, 10 H, H-4¦, H-5%, H-9a¦,
H-9b¦, H-6a, H-6b, H-6¦, H-6a%, H-5¦, H-6b%),
3.60–3.59 (t, 1 H, H-2%), 3.56–3.52 (d, 1 H,
H-7¦), 2.85–2.81 (dd, 1 H, J 4.0, Jgem 11.8 Hz,
H-3e¦), 2.02 (s, 3 H, Ac), 1.96 (s, 3 H, Ac),
1.74 (t, 1 H, H-3a¦); 13C NMR (CD3OD,
100.6 MHz): l 176.51, 176.18, 175.09, 130.39,
130.28, 129.92, 106.92, 101.50 (C¦-2), 99.01,
79.78, 78.56, 77.52, 75.90, 73.92, 73.33, 71.82,
71.34, 70.98, 70.20, 65.27, 63.92, 63.81, 55.01,
51.27, 42.50 (C-3¦), 23.93 (Ac), 23.68 (Ac).
13
H, J 12.8 Hz, H-3a¦), 1.22 (s, 9 H, t-Bu); C
NMR (CDCl3, 100.6 MHz): l 178.51, 171.47,
171.20, 170.90, 170.70, 170.60, 170.34, 170.28,
169.02, 138.04, 137.46, 129.41, 128.83, 128.59,
128.50, 128.39, 126.90, 101.95, 100.53, 97.25,
96.70 (C-1, C-1%, C-2¦, benzylidene carbon),
74.51, 72.90, 72.62, 72.58, 69.95, 69.65, 69.33,
69.30, 67.97, 67.92, 67.88, 66.58, 63.53, 53.25,
49.83, 49.49, 38.39 (C-3¦), 30.00 [C(CH3)3],
27.58 (3 CH3), 23.50 (Ac), 23.33 (Ac), 21.76
(Ac), 21.49 (Ac), 21.17 (Ac), 21.13 (Ac), 20.96
(Ac); Anal. Calcd for C57H74N2O26: C, 56.90;
H, 6.21; N, 2.33. Found: C, 56.68; H, 6.36; N,
2.17.
Phenyl
4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-i-
glycero - - galacto - 2 - nonulopyranoside)onate
(methyl
5-acetamido-N-acetyl-
D-
D
(23).—A solution of compound 9 (6.64 g,
11.38 mmol) in 2-propenyl acetate (58 mL),
was treated with p-TsOH·H2O (108 mg, 0.57
mmol), and the mixture was stirred for 16 h at
60–65 °C. Et3N was then added, and the mix-
ture was concentrated to give a crude product
that was passed through a short silica gel
column eluted with 1:1 hexane–EtOAc to give
pure 23 as an amorphous solid in quantitative
yield: TLC Rf =0.53 (1:1 hexane–EtOAc) [h]D
Benzyl [(5-acetamido-3,5-dideoxy-
h - - galacto - non - 2 - ulopyranosylonic acid)-
(2“3)-i- -galactopyranosyl]-(1“3)-2-aceta-
mido-2-deoxy-h- -galactopyranoside (3).—To
D-glycero-
D
D
D
a solution of compound 22 (160 mg, 0.13
mmol) in dry pyridine (3 mL) was added
lithium iodide (500 mg, 3.76 mmol). After 6–8
h at 120–125 °C under an N2 atmosphere, the
dark-yellow soln was concentrated under vac-
uum to a crude product that was co-evapo-
rated with toluene and dissolved in EtOAc,
washed with satd aq NaCl, dried (Na2SO4)
and concentrated to give a bright-yellow solid
that was dissolved in 60% aq AcOH and
1
−58.2° (c 1.0, CHCl3); H NMR (CD2Cl2,
400 MHz): l 7.51–7.49 (m, 2 H, ArH), 7.39–
7.34 (m, 3 H, ArH), 5.88–5.82 (ddd, 1 H,
H-4), 5.65–5.62 (dd, 1 H, J 2.0 Hz, J 9.8 Hz,
H-5), 5.25 (t, 1 H, H-7), 4.90 (m, 1 H, H-8),
4.32–4.29 (dd, 1 H, J 1.6, J 12.2 Hz, H-9a),
4.14–4.03 (m, 2 H, H-9b, H-6), 3.62 (s, 3 H,
COOCH3), 2.80–2.68 (dd, 1 H, J3e,4 4.0, Jgem

J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
161
eluted with 1:5 hexane–EtOAc to give pure
12.2 Hz, H-3e), 2.39 (s, 3 H, Ac), 2.26 (s, 3 H,
Ac), 2.09 (dd, 1 H, H-3a), 2.08 (s, 6 H, 2 Ac),
compound 24 (282 mg, 52%) as a glassy white
1
13
solid: TLC Rf=0.35 (1:5 hexane–EtOAc); H
1.99 (s, 6 H, 2 Ac); C NMR (CD2Cl2, 100.6
NMR (CD2Cl2, 600 MHz): l 8.00–7.90 (m, 2
H, ArH), 7.90–7.80 (m, 2 H, ArH), 7.60–7.40
(m, 2 H, ArH), 7.40–7.20 (m 3 H, ArH),
5.52–5.49 (ddd, 1 H, H-4¦), 5.39 (s, 1 H,
benzylidene proton), 5.32–5.27 (t, 1 H, H-8¦),
5.17–5.15 (dd, 1 H, H-7¦), 5.14–5.11 (d, 1 H,
J1,2 8.4 Hz, H-1), 4.94–4.92 (dd, 1 H, J 10.4
Hz, H-6¦), 4.79–4.76 (dd, 1 H, H-6b), 4.58–
4.57 (d, 1 H, J1%,2% 7.2 Hz, H-1%), 4.47–4.39 (m,
2 H, H-9a¦, H-3), 4.33–4.29 (m, 2 H, H-3%,
OH-3), 4.24–4.19 (dd, 1 H, H-6a), 4.16–4.07
(dd, 1 H, H-6b%), 4.07–3.99 (m, 4 H, H-5¦,
H-2, H-9b¦, H-6a%), 3.95–3.94 (d, 1 H, J 2.8
Hz, H-4%), 3.90–3.80 (m, 4 H, H-5, COOCH3),
3.80–3.75 (t, 1 H, H-2%), 3.38 (s, 3 H, OCH3),
3.31 (d, 1 H, OH-2%), 2.90–2.80 (dd, 1 H, J
4.8, Jgem 12.4 Hz, H-3e¦), 2.30 (br, 3 H, Ac),
2.11 (s, 3 H, Ac), 2.08 (s, 3 H, Ac), 2.01 (s, 3
H, Ac), 1.93 (s, 3 H, Ac), 1.92–1.86 (t, 1 H, J
12.8 Hz, H-3a¦), 1.52 (s, 3 H, Ac), 1.25 (s, 9
H, t-Bu); 13C NMR (CDCl3, 100.6 MHz): l
171.26, 170.81, 170.78, 168.78, 166.50, 138.55,
134.80, 132.56, 129.78, 128.91, 127.21, 123.57,
104.95, 101.75, 99.76 (C-1, C-1%, benzylidene
carbon), 97.14 (C-2¦), 83.65, 75.89, 75.12,
73.75, 71.11, 70.59, 69.97, 69.25, 69.03, 6753,
67.36, 66.98, 63.80, 62.83, 57.76, 57.21, 56.70,
39.55 (C-3¦), 30.39 [C(CH3)3], 27.83 (3 CH3),
21.61 (Ac), 21.34 (Ac), 21.24 (2 Ac), 21.21
(Ac); Anal. Calcd for C55H68N2O26: C, 56.31;
H, 5.84; N, 2.39. Found: C, 57.31; H, 6.20; N,
2.59.
MHz): l 175.06, 173.74, 170.53, 170.44,
170.36, 169.75, 168.69, 136.63, 130.08, 130.20,
129.46, 89.19 (C-2), 72.28, 70.48, 69.04, 67.08,
62.44, 57.82, 52.85, 38.97 (C-3), 28.15, 25.97,
21.02, 20.99, 20.87; Anal. Calcd for
C28H35NO13S: C, 53.75; H, 5.64; N, 2.24; S,
5.13. Found: C, 53.73; H, 5.67; N, 2.06; S,
5.12.
Methyl [methyl 5-acetamido-N-acetyl-4,7,
8,9-tetra-O-acetyl-3,5-dideoxy-
D
-glycero-h- -
D
galacto - non - 2 - ulopyranosyl)onate] - (2“3)-
(4,6 - O - benzylidene - i - - galactopyranosyl)-
(1“4)-2-deoxy-2-phthalimido-6-O-trimethyl-
acetyl-i- -glucopyranoside (24)
D
D
Procedure A. A solution of donor 23 (544
mg, 0.87 mmol), disaccharide acceptor 8 (520
mg, 0.79 mmol), NIS (587 mg, 2.61 mmol) in
dry 3:1 CH2Cl2–MeCN (20 mL) containing
3A-MS (6 g) was stirred at −45 to −40 °C
for 1.5–2 h under an N2 atmosphere. TfOH
(70 mL) was then added dropwise, and stirring
was continued for 1 h at the same tempera-
ture. More donor 23 (544 mg, 0.87 mmol) and
TfOH (70 mL) were added, and stirring was
continued for an additional 1 h. The solution
was neutralized with satd aq NaHCO3, solids
were filtered off, and the organic layer was
washed with satd aq NaHCO3 soln, 10%
Na2S2O3, water, dried (Na2SO4) and concen-
trated and the crude mixture was passed
through a short silica gel column eluted with
1:5 hexane–EtOAc to give pure compound 24
(550 mg, 55.0%) as a white glassy solid.
Procedure B. A solution of donor 23 (713
mg, 1.14 mmol), disaccharide acceptor 8 (300
mg, 0.46 mmol), NIS (770 mg, 3.42 mmol) in
dry 3:1 CH2Cl2–MeCN (15 mL) containing
3A-MS (4–5 g) was stirred at −45 to −
40 °C for 1.5–2 h under an N2 atmosphere.
TfOH (100 mL) was then added dropwise, and
stirring was continued for 1 h at the same
temperature. The solution was neutralized
with satd aq NaHCO3, solids were filtered off,
and the organic layer was washed with satd aq
NaHCO3, 10% Na2S2O3, water, dried
(Na2SO4), and concentrated under reduced
pressure to give a crude mixture that was
passed through a short silica gel column
Methyl
[methyl
5-acetamido-N-acetyl-
4,7,8,9-tetra-O-acetyl-3,5-dideoxy-
D
-glycero-h-
D
-galacto-non-2-ulopyranosy)onate] -(2“3)-
(2-O-acetyl-4,6-O-benzylidene-i-
D
-galactopy-
ranosyl)-(1“4)-2-phthalimido-2-O-acetyl-6-
O - trimethylacetyl - 2 - deoxy - i -
D
- glucopyra-
noside (25).—Compound 24 (150 mg) was
acetylated with 1:1 pyridine–Ac2O (8 mL)
overnight at rt, and concentrated under vac-
uum to give a crude product that was passed
through a short silica gel column eluting with
1:4 hexane–EtOAc to give compound 25 (134
mg) as a glassy white solid in 78% yield: TLC
Rf =0.35 (1:5 hexane–EtOAc); 1H NMR
(CD2Cl2, 600 MHz): l 7.85–7.76 (m, 4 H,
ArH), 7.60–7.20 (m, 5 H, ArH), 5.78–5.73 (t,

162
J. Xia et al. / Carbohydrate Research 328 (2000) 147–163
acid was dissolved in 60% aq AcOH, stirred at
60–65 °C for 4–6 h, then concentrated to a
crude mixture which was dissolved in MeOH
(5 mL) and deacetylated with 1 M CH3ONa
overnight at rt, concentrated under vacuum to
a crude product that was passed through a
short silica gel column eluted with 3:1:1 n-
C3H7OH–HOAc–water to give compound 1
(5 mg) as an amorphous solid in a total yield
of 12%.
1 H, J 8.4 Hz, H-3), 5.55–5.51 (m, 1 H, H-8¦),
5.47–5.44 (ddd, 1 H, H-4¦), 5.38 (s, 1 H,
benzylidene H), 5.28–5.26 (d, 1 H, J1,2 8.4 Hz,
H-1), 5.22–5.20 (dd, 1 H, H-7¦), 5.10–4.97
(dd, 1 H, H-2%), 4.78–4.75 (dd, 1 H, H-6¦),
4.73–4.71 (d, 1 H, J1%,2% 8.0 Hz, H-1%), 4.67–
4.64 (dd, 1 H, H-5), 4.53–4.50 (dd, 1 H, J 3.2
Hz, J 8.4 Hz, H-3%), 4.41–4.38 (dd, 1 H,
H-9a¦), 4.27–4.12 (m, 4 H, H-5¦, H-6b%, H-6a,
H-2), 4.07–3.99 (m, 2 H, H-9b¦, H-6a%), 3.86–
3.80 (m, 5 H, H-6b, H-4, OCH3), 3.80–3.79
(d, 1 H, J 3.2 Hz, H-4%), 3.48–3.46 (s, 1 H,
H-5%), 3.42 (s, 3 H, OCH3), 2.80–2.72 (dd, 1
H, J 4.4 Hz, Jgem 13.2 Hz, H-3e¦), 2.34 (s, 3 H,
Ac), 2.28 (s, 3 H, Ac), 2.24 (s, 3 H, Ac), 2.17
(s, 3 H, Ac), 2.09 (s, 3 H, Ac), 2.05 (s, 3 H,
Ac), 1.94 (s, 3 H, Ac), 1.89 (s, 3 H, Ac),
1.67–1.61 (t, 1 H, Jgem 12.8 Hz, H-3a¦), 1.20
(s, 9 H, t-Bu); 13C NMR (CDCl3, 100.6 MHz):
l 178.66, 173.83, 173.63, 170.71, 170.38,
170.13, 169.99, 169.21, 101.89, 101.26, 99.22,
98.17 (C-1, C-1%, benzylidene C, C-2¦), 77.77,
74.84, 73.71, 72.46, 71.27, 70.28, 69.73, 69.05,
68.54, 67.61, 66.91, 66.61, 62.92, 62.52, 57.02,
56.64, 55.20, 39.21 (C-2¦), 27.30 (3 CH3),
21.61 (Ac), 21.29 (Ac), 21.15 (Ac), 20.91 (Ac),
20.87 (Ac), 20.82 (Ac), 20.68 (Ac); Anal.
Calcd for C59H72N2O28: C, 56.37; H, 5.77; N,
2.28. Found: C, 57.21; H, 6.17; N, 2.15.
Acknowledgements
This work was supported by Grant No.
CA63218, CA35329 and in part by Grant No.
P30CA16056, all awarded by the National
Cancer Institute.
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