Chemical synthesis of β-D-GlcpA(2SO4)-(1→3)-D-GalpNAc(6SO4), the disaccharide repeating unit of shark cartilage chondroitin sulfate D, and of its methyl β-D-glycoside derivative

Article abstract of DOI:10.1039/b002835p

The syntheses of sodium O-(disodium 2-O-sulfonato-β-D-glucopyranosyluronate)-(1→3)-2-acetamido-2-deoxy-6- O-sulfonato-D-galactopyranose 1, which represents a structural element of shark cartilage chondroitin sulfate D, and of its methyl β-D-glycoside derivative 2 are reported for the first time. The glucuronyl donor 10 is prepared in a straightforward manner from D-glucose, whereas the glycosyl acceptors 20 and 21 are obtained from known 3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-1-O-trichloroacetimidoyl- α-D-glucopyranose through glycosylation with benzyl alcohol and methanol, respectively, and subsequent transformation into D-galacto synthons by selective inversion of configuration at C-4. Unexpected pyranose → furanose ring contraction as well as 3,6-anhydro-derivative formation in the D-galacto series are also reported. Stereocontrolled coupling of the imidate 10 with the alcohols 20 and 21 afforded the corresponding β-linked disaccharide derivatives 24 and 25, respectively, which are submitted to radical reduction of the N-trichloroacetyl groups, O-desilylation, saponification, O-sulfonation, and catalytic hydrogenation to provide the target molecules 1 and 2, respectively, in high yields. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/b002835p

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Chemical synthesis of ꢀ-D-GlcpA(2SO4)-(1→3)-D-GalpNAc(6SO4),
the disaccharide repeating unit of shark cartilage chondroitin
sulfate D, and of its methyl ꢀ-D-glycoside derivative
1
Nathalie Karst and Jean-Claude Jacquinet*
Institut de Chimie Organique et Analytique, UPRES-A CNRS 6005, UFR Faculté des Sciences,
Université d’Orléans, BP 6759, F-45067 Orléans, France
Received (in Cambridge, UK) 10th April 2000, Accepted 19th June 2000
Published on the Web 19th July 2000
The syntheses of sodium O-(disodium 2-O-sulfonato-β--glucopyranosyluronate)-(1→3)-2-acetamido-2-deoxy-6-O-
sulfonato--galactopyranose 1, which represents a structural element of shark cartilage chondroitin sulfate D, and
of its methyl β--glycoside derivative 2 are reported for the first time. The glucuronyl donor 10 is prepared in a
straightforward manner from -glucose, whereas the glycosyl acceptors 20 and 21 are obtained from known 3,4,6-tri-
O-acetyl-2-deoxy-2-trichloroacetamido-1-O-trichloroacetimidoyl-α--glucopyranose through glycosylation with
benzyl alcohol and methanol, respectively, and subsequent transformation into -galacto synthons by selective
inversion of configuration at C-4. Unexpected pyranose → furanose ring contraction as well as 3,6-anhydro-
derivative formation in the -galacto series are also reported. Stereocontrolled coupling of the imidate 10 with the
alcohols 20 and 21 afforded the corresponding β-linked disaccharide derivatives 24 and 25, respectively, which are
submitted to radical reduction of the N-trichloroacetyl groups, O-desilylation, saponification, O-sulfonation, and
catalytic hydrogenation to provide the target molecules 1 and 2, respectively, in high yields.
Besides this, CS-D was found to promote neurite outgrowth
Introduction
for hippocampal and rat embrionic mesencephalic neurons.12
Chondroitin sulfate (CS) proteoglycans are widely distributed
among various tissues and exhibit a large variety of biological
Since most of the observed effects depend on binding of
glycosaminoglycan chains to proteins, determination of the
functions. They are found in the extracellular matrix of con-
precise structure and size of oligosaccharide sequences involved
nective tissues, at the surface of many cells, and in intracellular
in such binding is of prime importance. Until now, the detailed
secretory granules.1,2 They are linear copolymers built essen-
tially from dimeric units composed of -glucuronic acid (GlcA)
and 2-acetamido-2-deoxy--galactose (GalNAc), namely [4)-β-
-GlcpA-(1→3)-β--GalpNAc-(1→]n. Several types of CS (A,
structural and functional analyses of CS-D fragments have
been hampered by a lack of analytical tools. Although various
oligosaccharide fragments were prepared4–6 using bacterial
enzymes (chondroitinase, hyaluronidase), their structures were
B, C, D, E, and K) having sulfate(s) at various positions are
converted to unsaturated forms by the action of the eliminases,
known. These sulfation patterns give rise to biologically
and consequently are not suitable for binding assays, or to be
important functions deeply related to the position and the
number of sulfate groups. However, homogeneous polymers
(i.e. composed of regular repeating units) are not found in
used as acceptor substrates for biosynthetic enzymes. Thus,
chemical synthesis of molecules of definite size and structure
remains one of the most efficient way to address these
Nature, and species containing irregular sequences are often
problems.
encountered. These microheterogeneities complicate to a larger
In the last decade, several syntheses of CS-A and CS-C frag-
extent accurate biological studies, but are potential sites for
ments have been reported, such as those of di-,13–15 tri-,15–17
specific recognition processes. Whereas CS-A and CS-C (sul-
fated at C-4 and C-6 of the aminosugar moiety, respectively),
the most abundant types, were extensively studied, the other
variants, and especially CS-D (sulfated at C-6 of the GalNAc
tetra-,15 and pentasaccharides,18 but, to the best of our know-
ledge, no synthetic work on the -type appeared in the liter-
ature. As a primary target, we now report for the first time on
the chemical synthesis of the basic disaccharide repeating unit
of CS-D, compound 1, and those of its methyl β--glycoside
and C-2 of the GlcA units), draw less attention.
Shark cartilage is the major natural source of CS-D, and
commercial preparations are now available. The structure of the
basic disulfated disaccharide of CS-D was first established
by Seno and Murakami,3 and, more recently, several sulfated
oligosaccharides were isolated4–6 from shark cartilage CS-D,
1
and their structures were determined by high-field H NMR
spectroscopy. The interest in shark cartilage, and a fortiori
for CS-D, arose at the beginning of the eighties when it was
claimed7 that it contained a substance that strongly inhibits the
growth of new blood vessels toward solid tumors. The discovery
of this antiangiogenic activity led to numerous reports and to
the development of new drugs8,9 based on shark cartilage
extracts. However, clinical trials that support their beneficial
effects are anecdotal, and a matter of controversy.10,11 Indeed,
no structure–activity relationship studies were undertaken on
these mixtures of molecules.
derivative 2, in which the methyl group is suitable as a marker
for NMR studies.
Results and discussion
For the syntheses of the target disaccharides 1 and 2, a common
glycosyl donor (10) was designed, which could be condensed
DOI: 10.1039/b002835p
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This journal is © The Royal Society of Chemistry 2000
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with suitably protected glycosyl acceptors, namely 20 and 21.
As far as structures 1 and 2 contain sulfate esters, we first
planned to temporarily protect the hydroxy groups which
would ultimately carry these substituents with ester groups, and
those which should remain free with easily removable benzyl
ethers. This provides a stereocontrolling auxiliary at C-2 of the
glycosyl donor which would induce a 1,2-trans linkage form-
ation. Since -galactosamine is a rather expensive sugar, the
glycosyl acceptors 20 and 21 were prepared by selective inver-
sion of configuration at C-4 of easily attainable -glucosamine-
derived synthons. All glycosylation reactions were achieved by
using trichloroacetimidates.19
acetonitrile and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to
give the crystalline α-imidate 10 in 71% overall yield, the ano-
1
meric configuration of which was deduced from its H NMR
spectrum (J1,2 3.7 Hz). In this sequence, most of the compounds
were isolated by simple crystallization, thus avoiding tedious
chromatographic separations, and allowing a multigram-scale
preparation of the key intermediate 10.
Preparation of the glycosyl acceptors
For the syntheses of the glycosyl acceptors 20 and 21, the
first requirement was the stereocontrolled and high yielding
preparation of the benzyl (12) and methyl (13) β--glycosides.
We previously demonstrated16,23 that 2-deoxy-2-trichloroacet-
amido--glucopyranose derivatives activated at C-1 were very
efficient glycosyl donors for the synthesis of 1,2-trans-2-amino-
2-deoxy--glucosides, and that the N-trichloroacetyl group in
the products could be easily transformed into N-acetyl under
neutral conditions using tributylstannane (TBTH). In addition,
the N-trichloroacetyl group provides a much better solubility
in the usual organic solvents than does the N-acetyl group.
Thus, treatment of easily available 3,4,6-tri-O-acetyl-2-deoxy-2-
trichloroacetamido-1-O-trichloroacetimidoyl-α--glucopyr-
anose23 11 with benzyl alcohol and methanol, in dichloro-
methane, in the presence of trimethylsilyl triflate (15% based on
11), afforded readily the crystalline benzyl (12) and methyl (13)
glycosides in 89 and 90% yield, respectively (Scheme 2). No
Preparation of the glycosyl donor
Synthesis of the glycosyl donor 10 was achieved in a straight-
forward manner as follows (Scheme 1). The known tetraacetate
Scheme 1 Reagents and conditions: (i) 4-Methoxyphenol, 4 Å mol.
sieves, TMSOTf (0.15 mol equiv.), CH2Cl2, 0 ЊC, 2 h; (ii) MeONa,
MeOH, 16 h; (iii) PhCHO, TFA, 20 min; (iv) PhCOCl, pyridine,
CH2Cl2, 0 ЊC, 1 h 30 min; (v) Me3NؒBH3, AlCl3, diethyl ether–CH2Cl2,
0 ЊC, 2 h; (vi) CrO3–H2SO4 (Jones reagent), acetone, 1 h; then MeO-
COCl, Et3N, DMAP, CH2Cl2, 0 ЊC → rt, 2 h; (vii) CAN, toluene–
acetonitrile–water (1:1.5:1), 20 min; then CCl3CN, DBU, CH2Cl2,
0 ЊC, 10 min. MP = 4-methoxyphenyl.
3,20 easily prepared in three steps from commercially available
1,2:5,6-di-O-isopropylidene-α--glucofuranose, was treated
with 4-methoxyphenol and trimethylsilyl triflate (TMSOTf,
0.15 mol equiv.), in dichloromethane, to afford the crystalline
glycoside 4 in 69% yield. Transesterification of 4 with methan-
olic sodium methoxide gave the corresponding crystalline triol
5 in 89% yield, which was treated with benzaldehyde and
trifluoroacetic acid (TFA, 5%, v/v) to afford the crystalline
benzylidene acetal 6 in 84% yield. Treatment of 6 with benzoyl
chloride in pyridine provided the crystalline benzoate 7 in 83%
yield. Regioselective ring opening of the benzylidene acetal
with borane–trimethylamine complex21 and aluminium tri-
chloride afforded the crystalline alcohol 8 in 64% yield. Jones
oxidation (chromium trioxide in sulfuric acid) of 8 in acetone
gave the intermediate acid, which was directly treated with
methyl chloroformate, triethylamine, and 4-(dimethylamino)-
pyridine (DMAP) in dichloromethane to afford the crystalline
methyl uronate 9 in 68% overall yield. Introduction of the
trichloroacetimidoyl group at C-1 was then achieved through
oxidative removal of the 4-methoxyphenyl glycoside with
cerium() ammonium nitrate22 (CAN), followed by imidoyl-
ation of the intermediate free hemiacetal with trichloro-
Scheme 2 Reagents and conditions: (i) PhCH2OH, 4 Å mol. sieves,
TMSOTf (0.15 mol equiv.), CH2Cl2, 1 h (for 11 → 12); MeOH, 3 Å
mol. sieves, TMSOTf (0.15 mol equiv.), CH2Cl2, 1 h (for 11 → 13);
(ii) MeONa, MeOH, 16 h; then (CH3)3CCOCl, pyridine, CH2Cl2, 0 ЊC,
1 h 30 min (for 12 → 14, and 13 → 15); (iii) (CF3SO2)2O, pyridine,
CH2Cl2, Ϫ15 ЊC → 0 ЊC, 2 h; then NaNO2, DMF, 1 h 30 min (for
14 → 16, and 15 → 17); (iv) PhCH2Br, Bu4NϩIϪ, NaH, THF,
0 ЊC → rt, 5 h (for 16 → 18, and 17 → 19); (v) MeONa, MeOH,
48 h; then TBDMSCl, imidazole, DMF, 0 ЊC, 40 min (for 18 → 20,
and 19 → 21). TCA = trichloroacetyl; Piv = 2,2-dimethylpropionyl
(pivaloyl).
corresponding α-isomers were obtained in these reactions, and
the physical data for 13 are in agreement with those reported.24
Transesterification of 12 and 13 with methanolic sodium
methoxide gave the corresponding triols, which were treated
with pivaloyl chloride (2 mol equiv.) and pyridine in dichloro-
methane at 0 ЊC to afford selectively the crystalline 3,6-di-O-
pivaloyl derivatives 14 and 15 in 86 and 82% yield, respec-
tively. Inversion of configuration at C-4 was then achieved by
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J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717

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treatment of 14 and 15 with trifluoromethanesulfonic
anhydride and pyridine in dichloromethane at Ϫ15 ЊC, followed
by nucleophilic displacement of the intermediate triflates with
sodium nitrite25 in N,N-dimethylformamide (DMF) to afford
the crystalline, corresponding 3,6-di-O-pivaloyl--galacto
derivatives 16 and 17 in 65 and 67% overall yield, respectively.
The 1H NMR spectra of 16 and 17 showed signals at δ 2.50 and
2.25, respectively, attributed, after exchange with D2O, to 4-
hydroxy groups. The J-values (J3,4 3.2, J4,5 0.8 Hz) observed for
H-4 in both compounds fit quite well with those expected for a
-galacto structure. To follow the initial scheme, benzylation
at O-4 was next studied. Since the alcohols 16 and 17 were
substituted with ester groups, alkylation reactions under basic
conditions had to be avoided to prevent acyl migration.
Consequently, the alcohol 17 was treated with 4-methoxyphenyl
trichloroacetimidate,26 a reagent much more reactive than its
corresponding benzyl analogue, in dichloromethane, in the
presence of trifluoromethanesulfonic acid27 (0.1 mol equiv.),
but no 4-O-benzyl derivative could be isolated. The only detect-
able product was an isomer of the starting material, the
were always preponderant. As far as esters can be obtained
from non-hindered alcohols through the Mitsunobu reaction,
the diol derived from 18 was treated with triphenylphosphine,
diethyl azodicarboxylate (DEAD), and benzoic acid in THF,
but no benzoylated derivative could be obtained. A major
product was isolated from the mixture, and was identified
through 1H NMR and mass analyses as the 3,6-anhydro deriv-
ative 23 (Scheme 3). Such an intramolecular nucleophilic attack
of O-3 upon C-6 to form a tetrahydrofuran ring has been
reported30 in the -galacto series in the reaction with triphenyl-
phosphine, and this occurred even when C-3 was substituted
by a benzyloxy group.31 Such a lack of selectivity in acylation
reactions prompt us to modify our initial strategy, and to use
another selective protection at O-6 which could be removed
under non-basic conditions after coupling with the methyl
uronate 10. Thus, when the diols derived from 18 and 19 were
treated with tert-butyldimethylsilyl chloride (TBDMSCl) and
imidazole in DMF at 0 ЊC, the crystalline silyl ethers 20 and 21
were obtained in 88 and 85% yield, respectively.
1
structure of which was tentatively assigned, through H NMR
and mass analyses, to the furanoside 22 (Scheme 3). Such a
Disaccharide syntheses
Condensation of the imidate 10 (1.25 mol equiv.) with the
alcohols 20 and 21 (1 mol equiv.), in dichloromethane, at room
temperature, and in the presence of TMSOTf (20% based on
10), afforded smoothly the crystalline disaccharide derivatives
24 and 25 in 62 and 68% yield, respectively (Scheme 4). The
anomeric configurations of the newly established inter-
1
glycosidic linkages were deduced from their H NMR spectra
(δ 5.15 and 5.08, J1Ј,2Ј 7.6 and 7.5 Hz, respectively). The N-tri-
chloroacetyl groups in 24 and 25 were readily transformed
into N-acetyl through treatment with tributylstannane16,23 and
azoisobutyronitrile (AIBN) in refluxing benzene to afford the
crystalline acetamides 26 and 27 in 92 and 82% yield, respec-
tively. We previously reported16 that O-desilylation with tetra-
butylammonium fluoride caused extensive β-elimination at the
methyl uronate moiety in disaccharide structures, but treatment
of compounds 26 and 27 with aq. acetic acid in THF afforded
the crystalline alcohols 28 and 29 in 82 and 85% yield, respect-
ively. Saponification of the ester groups in 28 and 29 was then
achieved through treatment with lithium hydroperoxide32 in
THF at 0 ЊC, a reagent which readily saponifies the methyl ester
groups without elimination side-reaction, followed by methan-
olic sodium hydroxide to give the corresponding hydroxy acids.
These intermediates were directly O-sulfonated by treatment
with the sulfur trioxide–trimethylamine complex in DMF at
50 ЊC, followed by ion-exchange chromatography (Naϩ resin) to
provide the sodium salts 30 and 31 in 66 and 63% overall yield,
respectively. While 6-O-sulfonation proceeded readily, 2Ј-O-
sulfonation required a longer reaction time and a large excess of
reagent to go to completion. Comparison of the 1H NMR spec-
tra, recorded in deuterated methanol, of 30 and 31 and of their
non-sulfated hydroxy acid precursors, showed the expected13
downfield shifts (≈0.5 ppm) of the signals for Ha-6 and Hb-6
in sulfates 30 and 31, and downfield shifts (0.4 and 0.6 ppm,
respectively) of the signals for H-2Ј in 30 and 31, in good
agreement with those reported33 for 2-O-sulfonated -glucu-
ronic acid residues in synthetic disaccharides. These chemical-
shift differences indicated clearly that sulfation occurred at O-6
and O-2Ј. Final deprotection on 30 and 31 was then achieved by
catalytic hydrogenation (Pd-C in methanol–water) to afford
nearly quantitatively the target molecules 1 and 2, respectively.
The 1H and 13C NMR spectra of disaccharides 1 and 2 were in
full agreement with the expected structures, and in accord with
those reported4,6 for oligosaccharide fragments isolated from
shark cartilage after digestion with testicular hyaluronidase and
containing non-modified CS-D disaccharide unit.
Scheme 3 Reagents and conditions: (i) 4-Methoxybenzyl trichloro-
acetimidate, CF3SO3H (0.1 mol equiv.), CH2Cl2, 0 ЊC → rt, 2 h;
(ii) MeONa, MeOH, 48 h; then Ph3P, DEAD, PhCOOH, THF, rt, 1 h,
then 60 ЊC, 3 h.
modification of structure should result from a ring-closure
process involving O-4 participation in a transient open-
chain methyloxonium ion, and was not unexpected in the
-galacto series. For instance, in the Fischer glycosylation
reaction of -galactose with methanol, up to 50% of methyl
β--galactofuranoside can be isolated, and the presence of the
axial 4-hydroxy group in the starting pyranose was postulated28
to be the driving force of this glycosidic modification. In the
present case, additional steric hindrance caused by the bulky
pivaloyl groups at O-3 and O-6 should prevent alkylation from
taking place at O-4, and favour the ring-contraction process. It
is noteworthy that in the absence of alkylating reagent, or under
the catalysis of trimethylsilyl triflate (details not presented in
the Experimental section), similar ring contraction occurred.
However, treatment of the alcohols 16 and 17 with benzyl
bromide, tetrabutylammonium iodide, and sodium hydride in
tetrahydrofuran (THF) afforded readily the 4-O-benzyl deriv-
atives 18 and 19 in 81 and 80% yield, respectively. The 1H NMR
spectra for 18 and 19 are in complete agreement with the
expected structures, and showed that no ester migration
occurred under these basic conditions.
Transformation of the diesters 18 and 19 into the glycosyl
acceptors 20 and 21 was then achieved as follows. Trans-
esterification of compounds 18 and 19 with methanolic sodium
methoxide afforded quantitatively the corresponding diol
derivatives. Attempted selective 6-O-benzoylation of these
3,6-diols with benzoyl chloride in pyridine at low temperature,
benzoyl cyanide29 or benzoic anhydride in pyridine or
acetonitrile, or N-benzoylimidazole in dichloromethane failed,
and led to mixtures in which the 3,6-di-O-benzoyl derivatives
In conclusion, stereocontrolled and high yielding syntheses
of the basic disaccharide unit of CS-D, 1, and its methyl
β--glycoside derivative 2 are reported for the first time, and the
J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717
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pyranose20 3 (10 g, 23 mmol), 4-methoxyphenol (5.67 g, 57
mmol), and 4 Å powdered molecular sieves (5 g) in dry dichloro-
methane (100 cm3) was stirred for 30 min at rt under dry argon,
then cooled to 0 ЊC. TMSOTf (0.63 cm3, 3.45 mmol) was added,
and the mixture was stirred for 2 h at 0 ЊC. Triethylamine
(1.5 cm3) was added, and the mixture was filtered, washed
successively with water, saturated aq. NaHCO3 and water,
dried (MgSO4), and concentrated under reduced pressure. The
residue was crystallized from ethyl acetate to give the glycoside 4
(7.94 g, 69%), mp 154 ЊC; [α]D22 Ϫ21 (c 1 in chloroform) (Found:
C, 62.1; H, 5.9. C26H30O10 requires C, 62.1; H, 6.0%); δH(CDCl3)
2.08, 2.11, 2.15 (9 H, 3 s, 3 × COCH3), 3.78 (1 H, m, H-5), 3.84
(1 H, t, J2,3 = J3,4 = 9.3, H-3), 3.85 (3 H, s, OCH3), 4.23 (1 H, dd,
J5,6a 2.7, J6a,6b 12.3, Ha-6), 4.32 (1 H, dd, J5,6b 5.5, J6a,6b 12.3,
Hb-6), 4.65 (2 H, s, CH2Ph), 4.94 (1 H, d, J1,2 7.9, H-1), 5.27
(1 H, dd, J3,4 9.3, J4,5 10.0, H-4), 5.37 (1 H, dd, J1,2 7.9, J2,3 9.3,
H-2), and 6.80–7.50 (9 H, m, ArH); m/z 525 [M ϩ Na]ϩ, 379
[M Ϫ OC6H4OCH3]ϩ.
4-Methoxyphenyl 3-O-benzyl-ꢀ-D-glucopyranoside 5
Methanolic sodium methoxide (1 mol dmϪ3; 1 cm3) was added
to a solution of the ester 4 (7 g, 14 mmol) in dry methanol
(70 cm3), and the mixture was stirred overnight at rt, then was
neutralized with Amberlite IR-120 (Hϩ) resin, filtered, and con-
centrated under reduced pressure. The residue was crystallized
from methanol to give the triol 5 (4.66 g, 89%), mp 136 ЊC; [α]D22
Ϫ23 (c 1 in methanol) (Found: C, 63.8; H, 6.4. C20H24O7
requires C, 63.8; H, 6.4%); δH(CDCl3) 2.06 (1 H, dd, J 6.5
and 6.7, HO-6), 2.44 (1 H, d, J 2.4, HO-4), 2.56 (1 H, d, J 2.6,
HO-2), 3.50 (3 H, m, H-5, H2-6), 3.74 (1 H, m, J1,2 7.9, J2,3 9.5,
J2,OH 2.6, H-2), 3.86 (3 H, s, OCH3), 3.95 (2 H, m, H-3, -4), 4.91
(1 H, d, J1,2 7.9, H-1), 5.0 (2 H, ABq, CH2Ph), and 6.80–7.50
(9 H, m, ArH); m/z 399 [M ϩ Na]ϩ, 253 [M Ϫ OC6H4OCH3]ϩ.
Scheme 4 Reagents and conditions: (i) TMSOTf (0.2 mol equiv.), 4 Å
mol. sieves, CH2Cl2, 30 min (for 10 ϩ 20 → 20, and 10 ϩ 21 → 25);
(ii) TBTH, AIBN, benzene, 80 ЊC, 1 h (for 24 → 26, and 25 → 27);
(iii) THF–acetic acid–water (3:3:1), rt, 72 h (for 26 → 28); rt, 4 h;
then 40 ЊC, 4 h (for 27 → 29); (iv) LiOH-H2O2, THF, 0 ЊC → rt,
16 h; then 4 mol dmϪ3 NaOH, MeOH, rt, 6 h; (v) Me3NؒSO3, DMF,
50 ЊC, 72 h; then ion-exchange resin (Naϩ) in CH2Cl2–MeOH–water
(9:5:1) (for 28 → 30, and 29 → 31); (vi) H2, 10% Pd on carbon,
MeOH–water (for 30 → 1, and 31 → 2).
4-Methoxyphenyl 3-O-benzyl-4,6-O-benzylidene-ꢀ-D-gluco-
pyranoside 6
TFA (5%, v/v; 1.8 cm3) was added at rt under dry argon to a
suspension of the triol 5 (4.66 g, 12.4 mmol) in benzaldehyde
(37 cm3), and the mixture was stirred vigorously for 20 min.
Triethylamine (5 cm3), then cold diethyl ether (100 cm3), were
added, and the solids were filtered off and washed with cold
diethyl ether to give the benzylidene acetal 6 (4.83 g, 84%), mp
201–202 ЊC (from ethanol); [α]D22 Ϫ26 (c 1 in chloroform)
(Found: C, 69.7; H, 6.0. C27H28O7 requires C, 69.8; H, 6.1%);
δH(CDCl3) 2.51 (1 H, d, J 2.4, HO-2), 3.53 (1 H, m, H-5), 3.70–
3.88 (4 H, m, H-2, -3, -4, Hax-6), 3.78 (3 H, s, OCH3), 4.37 (1 H,
dd, J5,6eq 4.9, J6ax,6eq 10.2, Heq-6), 4.90 (1 H, d, J1,2 7.3, H-1), 4.91
(2 H, ABq, CH2Ph), 5.60 (1 H, s, PhCH), and 6.80–7.50 (14 H,
m, ArH); m/z 465 [M ϩ H]ϩ, 341 [M Ϫ OC6H4OCH3]ϩ.
way is now open for the preparation of fragments of larger size.
These sulfated molecules are currently being evaluated in bio-
logical assays, and the results of these studies will be reported
elsewhere in due course.
Experimental
General
Mps were recorded with a Büchi apparatus and are un-
corrected. Optical rotations were measured on a Perkin-Elmer
241 polarimeter and [α]D-values are given in units of 10Ϫ1 deg
cm2 gϪ1. NMR spectra were recorded at 300 K on a Bruker
DPX 250 Avance (250 MHz) spectrometer with TMS as
internal reference, unless otherwise stated, and J-values are
quoted in Hz. Assignments were based on homo- and hetero-
nuclear correlations using the supplier’s software. Low-
resolution mass spectra were recorded with a Perkin-Elmer
SCIEX API 300 spectrometer in the ion-spray (IS) mode. TLC
was performed on Merck 60 F254 precoated plates, and com-
pounds were detected by spraying the plates with 5% H2SO4 in
EtOH and heating. Flash silica chromatography was performed
using Merck silica gel C60 (0.040–0.063 mm). Elemental anal-
yses were carried out at the Service Central de Microanalyse
du Centre National de la Recherche Scientifique (Vernaison,
France). Light petroleum refers to the fraction with distillation
range 40–60 ЊC.
4-Methoxyphenyl 2-O-benzoyl-3-O-benzyl-4,6-O-benzylidene-ꢀ-
D-glucopyranoside 7
Benzoyl chloride (3.6 cm3, 31 mmol) was added dropwise at
0 ЊC to a solution of the alcohol 6 (4.83 g, 10.4 mmol) in dry
pyridine (40 cm3) and dry dichloromethane (20 cm3), and the
mixture was allowed to attain rt under stirring within 1 h 30
min. Methanol (10 cm3) was then added, and the mixture was
diluted with dichloromethane (100 cm3), washed successively
with water, saturated aq. NaHCO3 and water, dried (MgSO4),
and concentrated under reduced pressure. The residue was crys-
tallized from ethyl acetate–light petroleum to give the ester 7
(4.9 g, 83%), mp 177 ЊC; [α]D22 ϩ42 (c 1 in chloroform) (Found: C,
71.8; H, 5.4. C34H32O8 requires C, 71.8; H, 5.7%); δH(CDCl3)
3.61 (1 H, m, H-5), 3.73 (3 H, s, OCH3), 3.86–3.97 (3 H, m, H-3,
-4, Hax-6), 4.43 (1 H, dd, J5,6eq 4.9, J6ax,6eq 10.4, Heq-6), 4.79 (2 H,
ABq, CH2Ph), 5.07 (1 H, d, J1,2 7.8, H-1), 5.53 (1 H, dd, J1,2 7.8,
J2,3 9.1, H-2), 5.64 (1 H, s, PhCH), and 6.70–8.10 (19 H, m,
ArH); m/z 591 [M ϩ Na]ϩ, 569 [M ϩ H]ϩ.
4-Methoxyphenyl 2,4,6-tri-O-acetyl-3-O-benzyl-ꢀ-D-gluco-
pyranoside 4
A
mixture of 1,2,4,6-tetra-O-acetyl-3-O-benzyl-β--gluco-
2712 J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717

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4-Methoxyphenyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranoside 8
acetonitrile (2 cm3, 20 mmol), and DBU (0.08 cm3, 0.5 mmol) in
dry dichloromethane (10 cm3) was stirred for 10 min at 0 ЊC,
then was directly purified by flash silica chromatography [light
petroleum–ethyl acetate (4:1), containing 0.1% of triethyl-
amine] to provide the imidate 10 (1 g, 71%), mp 102–104 ЊC
(from diethyl ether–light petroleum); [α]D22 ϩ103 (c 1 in chloro-
form) (Found: C, 56.6; H, 4.4; N, 2.4. C30H28Cl3NO8 requires C,
56.6; H, 4.4; N, 2.2%); δH(CDCl3) 3.72 (3 H, s, CO2CH3), 4.01
(1H, dd, J3,4 9.9, J4,5 10.1, H-4), 4.27 (1 H, t, J2,3 = J3,4 = 9.9,
H-3), 4.48 (1 H, d, J4,5 10.1, H-5), 4.73, 4.81 (4 H, 2 ABq,
2 × CH2Ph), 5.39 (1 H, dd, J1,2 3.7, J2,3 9.9, H-2), 6.64 (1 H, d,
A solution of aluminium trichloride (3.32 g, 24.8 mmol) in dry
diethyl ether (30 cm3) was added dropwise at 0 ЊC under dry
argon to a mixture of the acetal 7 (3.54 g, 6.2 mmol), borane–
trimethylamine complex (2.27 g, 31 mmol) and 4 Å powdered
molecular sieves (5 g) in dry dichloromethane (60 cm3). The
mixture was stirred at 0 ЊC for 2 h, then was filtered through a
pad of Celite, diluted with dichloromethane (100 cm3), and
stirred at rt for 1 h with aq. sulfuric acid (0.75 mol dmϪ3; 10
cm3). The organic layer was washed successively with saturated
aq. NaHCO3 and water, dried (MgSO4), and concentrated
under reduced pressure. A solution of the residue in methanol
(50 cm3) and dichloromethane (5 cm3) was stirred for 15 min at
rt with Amberlite IR-120 resin (Hϩ, 20 cm3), filtered, concen-
trated, and evaporated twice with methanol containing 1% of
acetic acid, then with toluene. The solid residue was recrystal-
lized from methanol to give the alcohol 8 (2.27 g, 64%), mp
114 ЊC; [α]D22 ϩ36 (c 1 in chloroform) (Found: C, 71.5; H, 6.2.
C34H34O8 requires C, 71.6; H, 6.0%); δH(CDCl3) 1.92 (1 H, dd,
J 6.2 and 7.9, HO-6), 3.58 (1 H, m, H-5), 3.73 (3 H, s, OCH3),
3.78 (1 H, m, J5,6a 4.4, J6a,6b 12.2, J6a,OH 7.9, Ha-6), 3.90 (2 H, m,
H-3, -4), 3.94 (1 H, m, J5,6b 2.7, J6a,6b 12.2, J6b,OH 6.2, Hb-6), 4.74,
4.82 (4 H, 2 ABq, 2 × CH2Ph), 5.04 (1H, d, J1,2 7.9, H-1), 5.50
(1 H, dd, J1,2 7.9, J2,3 9.0, H-2), and 6.70–8.10 (19 H, m, ArH);
m/z 607 [M ϩ Na]ϩ, 461 [M Ϫ OC6H4OCH3]ϩ.
J1,2 3.7, H-1), 7.10–8.0 (15 H, m, Ph), and 8.57 (1 H, s, C᎐NH);
᎐
δC(67.8 MHz; CDCl3) 55.82 (CO2CH3), 72.12, 72.79 (C-3, -4),
75.69, 75.86 (CH2Ph), 78.77, 79.15 (C-2, -5), 90.82 (CCl3), 93.70
(C-1), 121.95–137.68 (aromatic C), and 160.45, 165.44, 168.80
(C᎐O, C᎐N); m/z 660 [M ϩ Na]ϩ, 476 [M Ϫ CCl CONH]ϩ for
᎐
᎐
3
35Cl.
Benzyl 3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-ꢀ-D-
glucopyranoside 12
A mixture of 3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-
1-O-trichloroacetimidoyl-α--glucopyranose23 11 (2.85 g, 4.8
mmol), benzyl alcohol (1 cm3, 9.6 mmol), and 4 Å powdered
molecular sieves (2 g) in dry dichloromethane (30 cm3) was
stirred for 1 h at rt under dry argon. TMSOTf (0.14 cm3, 0.7
mmol) was added, and the mixture was stirred for 1 h. Triethyl-
amine (0.15 cm3) was added, and the mixture was diluted with
dichloromethane (50 cm3), filtered through a pad of Celite,
washed successively with saturated aq. NaHCO3 and water,
dried (MgSO4), and concentrated under reduced pressure. The
residue was crystallized from ethyl acetate–light petroleum to
give the benzyl glycoside 12 (2.37 g, 89%), mp 140–141 ЊC; [α]D22
Ϫ41 (c 1 in chloroform) (Found: C, 46.7; H, 4.4; N, 2.6.
C21H24Cl3NO9 requires C, 46.6; H, 4.5; N, 2.6%); δH(CDCl3)
2.03, 2.04, 2.14 (9 H, 3 s, 3 × COCH3), 3.69 (1 H, m, H-5), 4.06
(1 H, m, H-2), 4.20 (1 H, dd, J5,6a 2.5, J6a,6b 12.4, Ha-6), 4.32
(1 H, dd, J5,6b 4.7, J6a,6b 12.4, Hb-6), 4.65 (1 H, d, J1,2 8.4, H-1),
4.78 (2 H, ABq, CH2Ph), 5.15 (1 H, t, J3,4 = J4,5 = 9.5, H-4), 5.27
(1 H, dd, J2,3 10.4, J3,4 9.5, H-3), 6.63 (1 H, d, J2,NH 8.2, NH),
and 7.40 (5 H, m, Ph); m/z 559 [M ϩ NH4]ϩ, 434 [M Ϫ
OCH2Ph]ϩ for 35Cl.
Methyl (4-methoxyphenyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-
glucopyranosid)uronate 9
Chromium trioxide in sulfuric acid (3.34 mol dmϪ3; 8 cm3) was
added portionwise within 1 h at rt to a stirred solution of the
alcohol 8 (2.33 g, 4 mmol) in acetone (58 cm3). The mixture was
poured into ice-cold water and extracted with ethyl acetate
(3 × 50 cm3). The combined extracts were washed with water,
dried (MgSO4), concentrated, and purified by flash silica chrom-
atography [dichloromethane → dichloromethane–methanol
(49:1)] to afford the corresponding acid (1.87 g, 79%) as a pale
yellow syrup.
Methyl chloroformate (0.26 cm3, 3.3 mmol) was added at
0 ЊC under dry argon to a solution of the above isolated acid
and DMAP (38 mg, 0.3 mmol) in dry dichloromethane (50 cm3)
and triethylamine (0.5 cm3), and the mixture was stirred for 1 h
at 0 ЊC, then for 1 h at rt, after which it was washed successively
with 5% aq. NH4Cl and water, dried (MgSO4), and concen-
trated under reduced pressure. Flash silica chromatography
[ethyl acetate–light petroleum (4:1→2:1)] afforded the methyl
uronate 9 (1.56 g, 68% from 8), mp 97 ЊC (from ethyl acetate–
light petroleum): [α]D22 ϩ21 (c 1 in chloroform) (Found: C, 70.0;
H, 5.7. C35H34O9 requires C, 70.2, H, 5.7%); δH(C6D6) 3.31, 3.39
(6 H, 2 s, CO2CH3, OCH3), 3.95 (1 H, t, J2,3 = J3,4 = 8.7, H-3),
4.22 (1 H, d, J4,5 9.4, H-5), 4.31 (1 H, dd, J3,4 8.7, J4,5 9.4, H-4),
4.80, 4.82 (4 H, 2 ABq, 2 × CH2Ph), 5.10 (1 H, d, J1,2 7.3, H-1),
6.09 (1 H, dd, J1,2 7.3, J2,3 8.7, H-2), and 6.70–8.30 (19 H, m,
ArH); m/z 621 [M ϩ Na]ϩ, 475 [M Ϫ OC6H4OCH3]ϩ.
Methyl 3,4,6-tri-O-acetyl-2-deoxy-2-trichloroacetamido-ꢀ-D-
glucopyranoside 13
A mixture of the imidate 11 (3.47 g, 5.83 mmol), dry methanol
(1.15 cm3, 29 mmol), and 3 Å powdered molecular sieves (4 g)
in dry dichloromethane (35 cm3) was treated as described for
the preparation of 12. The residue was crystallized from ethyl
acetate–light petroleum to give the methyl glycoside 13 (2.44 g,
90%), mp 131–132 ЊC (lit.,24 131–133 ЊC); [α]D22 Ϫ5 (c 1 in chloro-
form) [lit.,24 Ϫ2.3 (c 2 in chloroform)]; δH(CDCl3) 1.98, 2.08,
2.12 (9 H, 3 s, 3 × COCH3), 3.50 (3 H, s, OCH3), 3.74 (1 H, m,
H-5), 3.98 (1 H, m, H-2), 4.16 (1 H, dd, J5,6a 3.0, J6a,6b 12.5,
Ha-6), 4.29 (1 H, dd, J5,6b 5.0, J6a,6b 12.5, Hb-6), 4.61 (1 H, d,
J1,2 8.0, H-1), 5.10 (1 H, t, J3,4 = J4,5 = 9.0, H-4), 5.36 (1 H, dd,
J2,3 10.0, J3,4 9.0, H-3), and 6.97 (1 H, d, J2,NH 9.0, NH); m/z 482
[M ϩ NH4]ϩ, 433 [M Ϫ OCH3]ϩ for 35Cl.
Methyl 2-O-benzoyl-3,4-di-O-benzyl-1-O-trichloroacetimidoyl-
ꢁ-D-glucopyranuronate 10
CAN (6.08 g, 11 mmol) was added to a solution of the glyco-
side 9 (1.33 g, 2.2 mmol) in toluene–acetonitrile–water
(1:1.5:1; 52.5 cm3), and the mixture was stirred for 20 min at rt,
then poured into ice-cold water, and extracted with ethyl acetate
(3 × 50 cm3). The combined extracts were washed successively
with saturated aq. NaHCO3 and water, dried (MgSO4), and
concentrated under reduced pressure. Flash silica chromato-
graphy [dichloromethane→dichloromethane–methanol (49:1)]
afforded the corresponding hemiacetal (1 g, 90%) as a pale
yellow solid.
Benzyl 2-deoxy-3,6-di-O-pivaloyl-2-trichloroacetamido-ꢀ-D-
glucopyranoside 14
Methanolic sodium methoxide (1 mol dmϪ3; 1 cm3) was added
to a solution of the ester 12 (3 g, 5.56 mmol) in dry methanol
(30 cm3), and the mixture was stirred overnight at rt, then was
neutralized with Amberlite IR-120 (Hϩ) resin, filtered, concen-
trated, and dried over phosphorus pentaoxide under reduced
pressure.
Pivaloyl chloride (2.7 cm3, 22 mmol) was added at 0 ЊC to a
solution of the above isolated triol in dry dichloromethane (20
A mixture of the above isolated hemiacetal, trichloro-
J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717
2713

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cm3) and dry pyridine (10 cm3), and the mixture was stirred for
1 h 30 min at 0 ЊC. Methanol (3 cm3) was then added, and the
mixture was diluted with dichloromethane (50 cm3), washed
successively with water, saturated aq. NaHCO3 and water, dried
(MgSO4), and concentrated under reduced pressure. The
residue was crystallized from ethyl acetate–light petroleum to
give the alcohol 14 (2.79 g, 86%), mp 139–140 ЊC; [α]D22 Ϫ52 (c 1
in chloroform) (Found: C, 51.6; H, 5.8; N, 2.7. C25H34Cl3NO8
requires C, 51.5; H, 5.9; N, 2.4%); δH(CDCl3) 1.16, 1.28 [18 H, 2
s, 2 × (CH3)3C], 3.01 (1 H, br s, HO-4), 3.52 (2 H, m, H-4, -5),
4.04 (1 H, m, J1,2 8.2, J2,3 10.6, J2,NH 9.0, H-2), 4.35 (1 H, dd,
J5,6a 5.0, J6a,6b 12.1, Ha-6), 4.46 (1 H, dd, J5,6b 2.0, J6a,6b 12.1,
Hb-6), 4.62 (1 H, d, J1,2 8.2, H-1), 4.74 (2 H, ABq, CH2Ph),
5.34 (1 H, dd, J2,3 10.6, J3,4 8.7, H-3), 6.80 (1 H, d, J2,NH 9.0,
NH), and 7.50 (5 H, m, Ph); m/z 601 [M ϩ NH4]ϩ, 476 [M Ϫ
OCH2Ph]ϩ for 35Cl.
2 s, 2 × (CH3)3C], 2.25 (1 H, br s, HO-4), 3.53 (3 H, s, OCH3),
3.79 (1 H, m, H-5), 3.99 (1 H, m, J3,4 3.2, J4,5 0.8, H-4), 4.24
(1 H, m, J1,2 8.2, J2,3 11.2, J2,NH 7.9, H-2), 4.34 (2 H, m, H2-6),
4.57 (1 H, d, J1,2 8.2, H-1), 5.20 (1 H, dd, J2,3 11.2, J3,4 3.2, H-3),
and 6.83 (1 H, d, J2,NH 7.9, NH); m/z 525 [M ϩ NH4]ϩ, 474
[M Ϫ OCH3]ϩ for 35Cl.
Benzyl 4-O-benzyl-2-deoxy-3,6-di-O-pivaloyl-2-trichloro-
acetamido-ꢀ-D-galactopyranoside 18
Sodium hydride (60% in mineral oil; 0.67 g, 17 mmol) was
added portionwise at 0 ЊC under dry argon to a solution of the
alcohol 16 (3.25 g, 5.6 mmol) in dry THF (33 cm3), and the
mixture was stirred at 0 ЊC for 30 min. Tetrabutylammonium
iodide (0.41 g 1.1 mmol) and benzyl bromide (1.7 cm3, 14
mmol) were then added, and the mixture was stirred for 1 h at
0 ЊC and 4 h at rt. Acetic acid (1 cm3) was then added carefully,
and the mixture was diluted with ethyl acetate (100 cm3),
washed successively with water, saturated aq. NaHCO3 and
water, dried (MgSO4), and concentrated under reduced pres-
sure. Flash silica chromatography [toluene–ethyl acetate (9:1)]
afforded the benzyl ether 18 (3.0 g, 81%) as a white solid, mp
150 ЊC (from ethyl acetate–light petroleum); [α]D22 Ϫ54 (c 1 in
chloroform) (Found: C, 57.2; H, 6.0, N, 2.0. C32H40Cl3NO8
requires C, 57.1; H, 6.0; N, 2.1%); δH(CDCl3) 1.18, 1.20 [18 H,
2 s, 2 × (CH3)3C], 3.74 (1 H, m, H-5), 3.88 (1H, dd, J3,4 3.0, J4,5
0.9, H-4), 4.13 (1 H, dd, J5,6a 6.1, J6a,6b 11.2, Ha-6), 4.33 (1 H, dd,
J5,6b 6.8, J6a,6b 11.2, Hb-6), 4.42 (1 H, m, J1,2 8.2, J2,3 11.2, J2,NH
8.7, H-2), 4.61 (1 H, d, J1,2 8.2, H-1), 4.73 (4 H, m, 2 × CH2Ph),
5.20 (1 H, dd, J2,3 11.2, J3,4 3.0, H-3), 6.61 (1 H, d, J2,NH 8.7,
NH), and 7.30 (10 H, m, Ph); m/z 691 [M ϩ NH4]ϩ, 566
[M Ϫ OCH2Ph]ϩ for 35Cl.
Methyl 2-deoxy-3,6-di-O-pivaloyl-2-trichloroacetamido-ꢀ-D-
glucopyranoside 15
Compound 13 (4.64 g, 10 mmol) was treated as described for
the preparation of 14 to give the alcohol 15 (4.16 g, 82%), mp
164–165 ЊC (from ethyl acetate–light petroleum); [α]D22 Ϫ33 (c 1
in chloroform) (Found: C, 45.1; H, 6.0; N, 2.8. C19H30Cl3NO8
requires C, 45.0; H, 6.0; N, 2.8%); δH(CDCl3) 1.19, 1.21 [18 H,
2 s, 2 × (CH3)3C], 3.21 (1 H, d, J 6.0, HO-4), 3.39 (3 H, s,
OCH3), 3.47 (1 H, m, H-5), 3.60 (1 H, m, J3,4 9.5, J4,5 10.0, J4,OH
6.0, H-4), 3.93 (1 H, m, J1,2 8.5, J2,3 10.0, J2,NH 9.0, H-2), 4.28
(1 H, dd, J5,6a 6.0, J6a,6b 12.5, Ha-6), 4.41 (1 H, dd, J5,6b 2.5, J6a,6b
12.5, Hb-6), 4.54 (1 H, d, J1,2 8.5, H-1), 5.52 (1H, dd, J2,3 10.0,
J3,4 9.5, H-3), and 7.07 (1 H, d, J2,NH 9.0, NH); m/z 524
[M ϩ NH4]ϩ for 35Cl.
Benzyl 2-deoxy-3,6-di-O-pivaloyl-2-trichloroacetamido-ꢀ-D-
galactopyranoside 16
Methyl 4-O-benzyl-2-deoxy-3,6-di-O-pivaloyl-2-trichloro-
acetamido-ꢀ-D-galactopyranoside 19
Trifluoromethanesulfonic anhydride (3.3 cm3, 15.4 mmol) was
added dropwise at Ϫ15 ЊC under dry argon to a solution of the
alcohol 14 (6.4 g, 11 mmol) in dry dichloromethane (60 cm3)
and dry pyridine (8 cm3), and the mixture was allowed to warm
up slowly to 0 ЊC within 2 h. Crushed ice was added, and the
mixture was diluted with dichloromethane (30 cm3), washed
successively with ice-cold water, brine and water, dried
(MgSO4), and concentrated under reduced pressure to give the
crude 4-O-triflyl intermediate (7.7 g, 98%) as a yellow foam,
which was immediatly engaged in the next reaction.
A mixture of the above isolated crude triflate and dried
sodium nitrite (3.7 g, 55 mmol) in dry DMF (70 cm3) was
stirred for 1 h 30 min at rt under dry argon, then was poured
into ice-cold water, and extracted with ethyl acetate (4 × 80
cm3). The combined extracts were washed successively with
cold hydrochloric acid (1 mol dmϪ3) and water, dried (MgSO4),
and concentrated under reduced pressure. The residue was crys-
tallized from ethyl acetate–light petroleum to afford the alcohol
16 (4.16 g, 65%), mp 169 ЊC; [α]D22 ϩ13 (c 1 in chloroform)
(Found: C, 51.7; H, 5.8; N, 2.5. C25H34Cl3NO8 requires C, 51.5;
H, 5.9; N, 2.4%); δH(CDCl3) 1.22, 1.26 [18 H, 2 s, 2 × (CH3)3C],
2.50 (1 H, br s, HO-4), 3.75 (1 H, m, H-5), 3.95 (1 H, dd, J3,4 3.2,
J4,5 0.8, H-4), 4.30 (3 H, m, H-2, H2-6), 4.62 (1 H, d, J1,2 8.4,
H-1), 4.74 (2 H, ABq, CH2Ph), 5.10 (1 H, dd, J2,3 11.1, J3,4 3.2,
H-3), 6.83 (1 H, d, J2,NH 8.9, NH), and 7.30 (5 H, m, Ph); m/z
601 [M ϩ NH4]ϩ, 474 [M Ϫ OCH2Ph]ϩ for 35Cl.
Compound 17 (4.1 g, 8.1 mmol) was treated as described for
the preparation of 18. Flash silica chromatography [light
petroleum–ethyl acetate (5:1)] provided the benzyl ether 19
(3.88 g, 80%) as a white foam; [α]D22 Ϫ4 (c 1 in chloroform)
(Found: C, 52.3; H, 6.1; N, 2.5. C26H36Cl3NO8 requires C, 52.3;
H, 6.1; N, 2.4%); δH(CDCl3) 1.19, 1.22 [18 H, 2 s, 2 × (CH3)3C],
3.49 (3 H, s, OCH3), 3.78 (1 H, m, H-5), 3.87 (1 H, dd, J3,4
3.0, J4,5 0.9, H-4), 4.11 (1 H, dd, J5,6a 6.2, J6a,6b 11.0, Ha-6), 4.30
(2 H, m, H-2, Ha-6), 4.57 (1 H, d, J1,2 8.4, H-1), 4.69 (2 H, ABq,
CH2Ph), 5.29 (1 H, dd, J2,3 11.1, J3,4 3.0, H-3), 6.70 (1 H, d, J2,NH
8.8, NH), and 7.40 (5 H, m, Ph); m/z 615 [M ϩ NH4]ϩ, 566
[M Ϫ OCH3]ϩ for 35Cl.
Benzyl 4-O-benzyl-6-O-(tert-butyldimethylsilyl)-2-deoxy-2-
trichloroacetamido-ꢀ-D-galactopyranoside 20
Methanolic sodium methoxide (1 mol dmϪ3; 5 cm3) was added
to a solution of the diester 18 (3 g, 4.5 mmol) in dry methanol,
and the mixture was stirred for 48 h, then was neutralized with
Amberlite IR-120 (Hϩ) resin, filtered, concentrated and dried
over phosphorus pentaoxide under reduced pressure.
A mixture of the residue, imidazole (1.1 g, 16.2 mmol) and
TBDMSCl (1.85 g, 8.1 mmol) in dry DMF (25 cm3) was stirred
for 40 min at 0 ЊC, then was diluted with ethyl acetate (100 cm3),
washed successively with saturated aq. NaHCO3 and water,
dried (MgSO4), and concentrated under reduced pressure.
Flash silica chromatography [toluene–ethyl acetate (7:1)]
afforded the alcohol 20 (2.45 g, 88%) as a white solid, mp 157–
158 ЊC (from ethyl acetate–light petroleum); [α]D22 Ϫ16 (c 1 in
chloroform) (Found: C, 54.3; H, 6.2; N, 2.5. C28H38Cl3NO6Si
requires C, 54.3; H, 6.2; N, 2.3%); δH(CDCl3) 0.13 [6 H, s,
Si(CH3)2], 0.95 [9 H, s, (CH3)3CSi], 2.56 (1 H, d, J 8.6, HO-3),
3.51 (1 H, m, H-5), 3.82 (2 H, m, H2-6), 3.86 (1 H, m, J1,2 8.0,
J2,3 10.0, J2,NH 7.0, H-2), 3.92 (2 H, m, H-3, -4), 4.62 (1 H, d, J1,2
8.0, H-1), 4.70, 4.75 (4 H, 2 ABq, 2 × CH2Ph), 6.73 (1 H, d,
Methyl 2-deoxy-3,6-di-O-pivaloyl-2-trichloroacetamido-ꢀ-D-
galactopyranoside 17
Compound 15 (4.96 g, 9.8 mmol) was treated as described for
the preparation of 16 to give the alcohol 17 (3.33 g, 67%), mp
177 ЊC (from ethyl acetate–light petroleum); [α]D22 ϩ19 (c 1 in
chloroform) (Found: C, 45.2; H, 6.0; N, 3.0. C19H30Cl3NO8
requires C, 45.0; H, 6.0; N, 2.8%); δH(CDCl3) 1.21, 1.27 [18 H,
2714
J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717

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J2,NH 7.0, NH), and 7.30 (10 H, m, Ph); m/z 636 [M ϩ NH4]ϩ,
512 [M Ϫ OCH2Ph]ϩ for 35Cl.
3.82 (1 H, m, J1,2 8.4, J2,3 11.1, J2,NH 6.6, H-2), 3.86 (1 H, dd,
J3Ј,4Ј 8.5, J4Ј,5Ј 9.5, H-4Ј), 4.02 (2 H, m, H2-6), 4.15 (1 H, t,
J2Ј,3Ј = J3Ј,4Ј = 8.5, H-3Ј), 4.22 (1 H, d, J4Ј,5Ј 9.5, H-5Ј), 4.47 (1 H,
dd, J3,4 3.0, J4,5 0.8, H-4), 4.75, 4.80, 4.89 (6 H, 3 ABq,
3 × CH2Ph), 5.02 (1 H, dd, J2,3 11.1, J3,4 3.0, H-3), 5.15 (1 H, d,
J1Ј,2Ј 7.6, H-1Ј), 5.16 (1 H, d, J1,2 8.4, H-1), 5.30 (2 H, ABq,
CH2Ph), 5.96 (1 H, dd, J1Ј,2Ј 7.6, J2Ј,3Ј 8.5, H-2Ј), 6.48 (1 H, d,
J2,NH 6.6, NH), and 7.10–8.40 (25 H, m, Ph); m/z 1112
[M ϩ NH4]ϩ for 35Cl.
Methyl 4-O-benzyl-6-O-(tert-butyldimethylsilyl)-2-deoxy-2-
trichloroacetamido-ꢀ-D-galactopyranoside 21
The diester 19 (3.88 g, 6.5 mmol) was treated as described for
the preparation of 20. Flash silica chromatography [toluene–
ethyl acetate (6:1)] provided the alcohol 21 (3 g, 85%) as a white
solid, mp 158–159 ЊC (from diethyl ether–light petroleum);
[α]D22 ϩ13 (c 1 in chloroform) (Found: C, 48.7; H, 6.3; N, 2.8.
C22H34Cl3NO6Si requires C, 48.7; H, 6.3; N, 2.6%); δH(CDCl3)
0.11 [6 H, s, Si(CH3)2], 0.98 [9 H, s, (CH3)3CSi], 2.50 (1 H, br s,
HO-3), 3.51 (3 H, s, OCH3), 3.56 (1 H, m, H-5), 3.71 (1 H, m,
J1,2 8.2, J2,3 10.6, J2,NH 7.0, H-2), 3.82 (2 H, m, H2-6), 3.97 (1 H,
dd, J3,4 3.4, J4,5 1.0, H-4), 4.05 (1 H, m, J2,3 10.6, J3,4 3.4, H-3),
4.58 (1 H, d, J1,2 8.2, H-1), 4.80 (2 H, ABq, CH2Ph), 6.82 (1 H,
d, J2,NH 7.0, NH), and 7.35 (5 H, m, Ph); m/z 561 [M ϩ NH4]ϩ,
512 [M Ϫ OCH3]ϩ for 35Cl.
Methyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-4-O-benzyl-6-O-(tert-butyldimethyl-
silyl)-2-deoxy-2-trichloroacetamido-ꢀ-D-galactopyranoside 25
Coupling of the donor 10 (0.82 g, 1.29 mmol) and the acceptor
21 (0.5 g, 0.92 mmol) as described for the preparation of 24
afforded the disaccharide 25 (0.64 g, 68%), mp 165–166 ЊC
(from ethanol); [α]D22 ϩ0.5 (c 1 in chloroform) (Found: C, 58.9;
H, 6.0; N, 1.4. C50H60Cl3NO13Si requires C, 59.0; H, 5.9; N,
1.4%); δH(C6D6) 0.21 [6 H, s, (CH3)2Si], 1.26 [9 H, s, (CH3)3CSi],
3.31 (3 H, s, OCH3), 3.46 (3 H, s, CO2CH3), 3.51 (1 H, m, H-5),
3.70 (1 H, m, H-2), 3.78 (1 H, dd, J3Ј,4Ј 8.5, J4Ј,5Ј 10.0, H-4Ј), 3.90
(2 H, m, H2-6), 4.08 (1 H, t, J2Ј,3Ј = J3Ј,4Ј = 8.5, H-3Ј), 4.14 (1 H,
d, J4Ј,5Ј 10.0, H-5Ј), 4.41 (1 H, dd, J3,4 3.0, J4,5 0.8, H-4), 4.65,
4.71 (4 H, 2 ABq, 2 × CH2Ph), 4.88 (1 H, d, J1,2 8.5, H-1), 4.98
(1 H, dd, J2,3 11.0, J3,4 3.0, H-3), 5.08 (1 H, d, J1Ј,2Ј 7.5, H-1Ј),
5.30 (2 H, ABq, CH2Ph), 5.88 (1 H, dd, J1Ј,2Ј 7.5, J2Ј,3Ј 8.5, H-2Ј),
6.42 (1 H, d, J2,NH 6.5, NH), and 7.10–8.40 (20 H, m, Ph); m/z
1035 [M ϩ NH4]ϩ for 35Cl.
Methyl 2-deoxy-3,6-di-O-pivaloyl-2-trichloroacetamido-ꢀ-D-
galactofuranoside 22
Triflic acid (0.1 mol dmϪ3; 0.4 cm3) was added at 0 ЊC to a solu-
tion of the alcohol 17 (0.2 g, 0.4 mmol) and 4-methoxybenzyl
trichloroacetimidate (0.34 g, 1.2 mmol) in dry dichloromethane
(10 cm3), and the mixture was allowed to warm slowly to rt
within 2 h. Triethylamine (0.15 cm3) was added, and the mix-
ture was concentrated under reduced pressure. Flash silica
chromatography [toluene–ethyl acetate (6:1)] gave the furano-
side 22 (64 mg, 32%) as a foam; δH(CDCl3) 1.22, 1.24 [18 H, 2 s,
2 × (CH3)3C], 3.41 (3 H, s, OCH3), 3.46 (1 H, br s, HO-5), 4.07
(1 H, m, J4,5 = J5,6a = 1.2, J5,6b 2.5, H-5), 4.33 (1 H, dd, J2,3 2.4,
J2,NH 8.0, H-2), 4.36 (2 H, m, H-4, Ha-6), 4.48 (1 H, dd, J5,6b 1.2,
J6a,6b 8.4, Hb-6), 4.94 (1 H, s, H-1), 5.03 (1 H, dd, J2,3 2.4, J3,4 0.7,
H-3), and 7.25 (1 H, d, J2,NH 8.7, NH); m/z 525 [M ϩ NH4]ϩ,
474 [M Ϫ OCH3]ϩ for 35Cl.
Benzyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-6-O-(tert-
butyldimethylsilyl)-2-deoxy-ꢀ-D-galactopyranoside 26
A mixture of the trichloroacetamide 24 (1.28 g, 1.17 mmol),
tributylstannane (1.7 cm3, 7 mmol) and AIBN (10 mg) in dry
benzene (25 cm3) was stirred for 30 min at rt under a flow of dry
argon, then heated for 1 h at 80 ЊC, cooled, and concentrated
under reduced pressure. The solid residue was stirred with light
petroleum (30 cm3) for 1 h at rt, filtered off, washed with
light petroleum, and recrystallized from ethanol to provide the
acetamide 26 (1.06, 92%), mp 175–176 ЊC; [α]D22 Ϫ21 (c 1 in
chloroform) (Found: C, 67.8; H, 6.9; N, 1.3. C56H67NO13Si
requires C, 67.9; H, 6.8; N, 1.4%); δH(CDCl3) 0.10 [6 H, s,
(CH3)2Si], 0.85 [9 H, s, (CH3)3CSi], 1.35 (3 H, s, COCH3), 3.22
(1 H, m, J1,2 8.2, J2,3 11.0, J2,NH 6.6, H-2), 3.53 (1 H, m, J4,5 0.8,
J5,6a 6.0, J5,6b 6.2, H-5), 3.59 (1 H, dd, J3Ј,4Ј 9.0, J4Ј,5Ј 9.5, H-4Ј),
3.72 (3 H, s, CO2CH3), 3.84 (1 H, t, J2Ј,3Ј = J3Ј,4Ј = 9.0, H-3Ј), 4.0
(4 H, m, H-4, 5Ј, H2-6), 4.60, 4.70 (4 H, 2 ABq, 2 × CH2Ph),
4.74 (1 H, d, J1,2 8.2, H-1), 4.76 (5 H, m, H-3, 2 × CH2Ph), 4.99
(1 H, d, J1Ј,2Ј 7.5, H-1Ј), 5.25 (1 H, d, J2,NH 6.6, NH), 5.32 (1 H,
dd, J1Ј,2Ј 7.5, J2Ј,3Ј 9.0, H-2Ј), and 7.0–8.0 (25 H, m, Ph); m/z
991 [M ϩ H]ϩ, 882 [M Ϫ OCH2Ph]ϩ.
Benzyl 3,6-anhydro-4-O-benzyl-2-deoxy-2-trichloroacetamido-ꢀ-
D-galactopyranoside 23
DEAD (0.02 cm3, 0.12 mmol) was added to a solution of the
diol derived from 18 (51 mg, 0.1 mmol), together with triphenyl-
phosphine (30 mg, 0.12 mmol) and benzoic acid (15 mg, 0.12
mmol) in dry THF (2 cm3), and the mixture was stirred for 1 h
at rt and for 3 h at 60 ЊC, then cooled, and concentrated under
reduced pressure. Flash silica chromatography [toluene–ethyl
acetate (6:1)] afforded the anhydro sugar 23 (29 mg, 60%) as a
white powder; δH(CDCl3) 3.93 (1 H, d, J4,5 1.8, H-4), 4.09 (1 H,
dd, J5,6a 3.0, J6a,6b 9.7, Ha-6), 4.45 (1 H, d, J6a,6b 9.7, Hb-6), 4.50
(2 H, m, H-2, -5), 4.67 (1 H, br s, H-3), 4.68 (2 H, ABq, CH2Ph),
4.73 (1 H, br s, H-1), 4.78 (2 H, ABq, CH2Ph), 6.51 (1 H, d,
J2,NH 8.2, NH), and 7.30 (10 H, m, Ph); m/z 504 [M ϩ NH4]ϩ,
487 [M ϩ H]ϩ, 379 [M Ϫ OCH2Ph]ϩ for 35Cl.
Benzyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-4-O-benzyl-6-O-(tert-butyldimethyl-
silyl)-2-deoxy-2-trichloroacetamido-ꢀ-D-galactopyranoside 24
Methyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-6-O-(tert-
butyldimethylsilyl)-2-deoxy-ꢀ-D-galactopyranoside 27
A mixture of the donor 10 (0.64 g, 1 mmol), the acceptor 20
(0.5 g, 0.8 mmol) and 4 Å powdered molecular sieves (0.5 g) in
dry dichloromethane (11 cm3) was stirred for 1 h at rt under dry
argon. A solution of TMSOTf in dry toluene (1 mol dmϪ3; 0.2
cm3) was added, and the mixture was stirred for 30 min. Tri-
ethylamine (0.15 cm3) was added, and the mixture was filtered
and concentrated under reduced pressure. Flash silica chrom-
atography [toluene–ethyl acetate (15:1), containing 0.1% of
triethylamine] afforded the disaccharide 24 (0.5 g, 62%), mp
161–162 ЊC (from ethanol); [α]D22 Ϫ20 (c 1 in chloroform)
(Found: C, 61.5; H, 5.9; N, 1.6. C56H64Cl3NO13Si requires C,
61.5; H, 5.9; N, 1.3%); δH(C6D6) 0.22 [6 H, s, (CH3)2Si], 1.20
[9 H, s, (CH3)3CSi], 3.53 (3 H, s, CO2CH3), 3.56 (1 H, m, H-5),
The trichloroacetamide 25 (1.02 g, 1 mmol) was treated as
described for the preparation of 26, then the product was
recrystallized from ethanol to afford the acetamide 27 (0.75 g,
82%), mp 85–86 ЊC; [α]D22 Ϫ0.5 (c 1 in chloroform) (Found: C,
65.6; H, 6.9; N, 1.7. C50H63NO13Si requires C, 65.7; H, 7.0; N,
1.6%); δH(CDCl3) 0.10 [6 H, s, (CH3)2Si], 0.80 [9 H, s,
(CH3)3CSi], 1.40 (3 H, s, COCH3), 3.12 (1 H, m, J1,2 8.5, J2,3
11.0, J2,NH 6.6, H-2), 3.36 (3 H, s, OCH3), 3.46 (1 H, m, J4,5 1.0,
J5,6a 6.5, J5,6b 6.6, H-5), 3.55 (1 H, t, J3Ј,4Ј = J4Ј,5Ј = 9.5, H-4Ј), 3.69
(3 H, s, CO2CH3), 3.82 (1H, t, J2,3 = J3,4 = 9.5, H-3Ј), 3.98 (4 H,
m, H-4,- 5Ј, H2-6), 4.67 (5 H, m, H-3, 2 × CH2Ph), 4.71 (1 H, d,
J1Ј,2Ј 7.5, H-1Ј), 4.73 (2 H, ABq, CH2Ph), 4.81 (1 H, d, J1,2 8.5,
H-1), 5.24 (1 H, d, J2,NH 6.6, NH), 5.30 (1 H, dd, J1Ј,2Ј 7.5, J2Ј,3Ј
J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717
2715

View Article Online
9.5, H-2Ј), and 7.0–8.0 (20 H, m, Ph); m/z 937 [M ϩ Na]ϩ, 915
[M ϩ H]ϩ, 883 [M Ϫ OCH3]ϩ.
chromatography [ethyl acetate–methanol–water (12:2:1)] gave
a fraction that was eluted from a column (1.5 × 20 cm)
of Sephadex SP-C25 (Naϩ) with dichloromethane–methanol–
water (9:5:1) to afford the sodium salt 30 (0.49 g, 66% from 28)
as a white powder; [α]D22 Ϫ20 (c 1 in methanol) (Found: C, 49.4;
H, 4.9; N, 1.3. C42H44NNa3O18S2ؒ2H2O requires C, 49.5; H, 4.7;
N, 1.4%); δH(CD3OD) 2.0 (3 H, s, COCH3), 3.85 (2 H, m, H-3Ј,
-5), 4.0 (1 H, dd, J3Ј,4Ј 9.0, J4Ј,5Ј 9.5, H-4Ј), 4.02 (1 H, dd, J2,3 11.0,
J3,4 3.0, H-3), 4.03 (1 H, dd, J1,2 8.1, J2,3 11.0, H-2), 4.12 (3 H, m,
H-2Ј, H2-6), 4.15 (1 H, d, J4Ј,5Ј 9.5, H-5Ј), 4.17 (1 H, dd, J3,4 3.0,
J4,5 0.8, H-4), 4.61 (1 H, d, J1Ј,2Ј 7.8, H-1Ј), 4.77 (1 H, d, J1,2 8.1,
H-1), 4.85 (8 H, m, 4 × CH2Ph), and 7.30 (20 H, m, Ph).
Benzyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-2-deoxy-ꢀ-D-
galactopyranoside 28
A solution of the silyl ether 26 (0.99 g, 1 mmol) in THF–acetic
acid–water (3:3:1; 7 cm3) was stirred at rt for 72 h, then was
concentrated under reduced pressure, and evaporated with
water (3 × 10 cm3). The residue was crystallized from ethanol to
afford the alcohol 28 (0.72 g, 82%), mp 208–209 ЊC; [α]D22 Ϫ28
(c 1 in chloroform) (Found: C, 68.8; H, 6.0; N, 1.6. C50H53NO13
requires C, 68.6; H, 6.1; N, 1.6%); δH(CDCl3) 1.40 (3 H, s,
COCH3), 2.01 (1 H, br s, HO-6), 3.24 (1 H, m, J1,2 8.4, J2,3 11.0,
J2,NH 6.6, H-2), 3.42 (2 H, m, H-5, Ha-6), 3.66 (1 H, m, Hb-6),
3.76 (3 H, s, CO2CH3), 3.90 (2 H, m, H-4, -4Ј), 4.03 (2 H, m,
H-3Ј, -5Ј), 4.75 (9 H, m, H-3, 4 × CH2Ph), 4.79 (1 H, d, J1Ј,2Ј
7.7, H-1Ј), 5.02 (1 H, d, J1,2 8.4, H-1), 5.25 (1 H, d, J2,NH 6.6,
NH), 5.35 (1 H, dd, J1Ј,2Ј 7.7, J2Ј,3Ј 9.5, H-2Ј), and 7.0–8.0 (25 H,
m, Ph); m/z 894 [M ϩ NH4]ϩ, 877 [M ϩ H]ϩ, 769 [M Ϫ
OCH2Ph]ϩ.
Sodium methyl O-(disodium 3,4-di-O-benzyl-2-O-sulfonato-ꢀ-D-
glucopyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-2-
deoxy-6-O-sulfonato-ꢀ-D-galactopyranoside 31
The ester 29 (0.55 g, 0.69 mmol) was treated as described for
the preparation of 30. Flash silica chromatography [dichloro-
methane–methanol (4:1→3:1)] afforded the corresponding
acid (425 mg, 90%) as a white solid; δH(CD3OD) 2.0 (3 H, s,
COCH3), 3.46 (3 H, s, OCH3), 3.48 (1 H, dd, J1Ј,2Ј 7.4, J2Ј,3Ј 9.5,
H-2Ј), 3.55 (2 H, m, H-3Ј, Ha-6), 3.66 (1 H, dd, J5,6b 5.0, J6a,6b
10.5, Hb-6), 3.70 (1 H, m, H-5), 3.78 (2 H, m, H-4Ј, -5Ј), 3.86
(1 H, dd, J2,3 11.0, J3,4 3.0, H-3), 4.01 (1 H, dd, J3,4 3.0, J4,5 0.8,
H-4), 4.13 (1 H, dd, J1,2 8.2, J2,3 11.0, H-2), 4.36 (1 H, d, J1,2 8.2,
H-1), 4.46 (1 H, d, J1Ј,2Ј 7.4, H-1Ј), 4.80 (6 H, m, 3 × CH2Ph),
and 7.30 (15 H, m, Ph).
The above isolated acid was O-sulfonated as described for the
preparation of 30. Flash silica chromatography [ethyl acetate–
methanol–water (6:2:1→5:2:1)] followed by ion-exchange
chromatography as described above afforded the sodium salt 31
(0.42 g, 63% from 29) as a white powder; [α]D22 Ϫ7 (c 1 in meth-
anol) (Found: C, 45.6; H, 4.8; N, 1.5. C36H40NNa3O18S2ؒ2H2O
requires C, 45.8; H, 4.7; N, 1.5%); δH(CD3OD) 2.08 (3 H, s,
COCH3), 3.44 (3 H, s, OCH3), 3.83 (1 H, m, J4,5 0.8, J5,6a 5.0,
J5,6b 6.0, H-5), 3.93 (2 H, m, H-3Ј, -4Ј), 3.94 (1 H, dd, J1,2, 8.1,
J2,3 11.0, H-2), 4.05 (1 H, dd, J2,3 11.0, J3,4 3.0, H-3), 4.09 (3 H,
m, H-2Ј, H2-6), 4.15 (1 H, d, J4Ј,5Ј 9.5, H-5Ј), 4.17 (1 H, dd, J3,4
3.0, J4,5 0.8, H-4), 4.57 (1 H, d, J1,2 8.1, H-1), 4.61 (1 H, d, J1Ј,2Ј
7.5, H-1Ј), 4.80 (6 H, m, 3 × CH2Ph), and 7.30 (15 H, m, Ph).
Methyl O-(methyl 2-O-benzoyl-3,4-di-O-benzyl-ꢀ-D-gluco-
pyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-2-deoxy-ꢀ-D-
galactopyranoside 29
A solution of the silyl ether 27 (0.6 g, 0.66 mmol) in THF–
acetic acid–water (3:3:1; 7 cm3) was stirred for 4 h at rt,
then was heated at 40 ЊC for 4 h, cooled, concentrated under
reduced pressure, and evaporated with water (3 × 10 cm3). The
residue was crystallized from ethanol to give the alcohol 29
(0.43 g, 85%), mp 185–186 ЊC; [α]D22 Ϫ8 (c 1 in chloroform)
(Found: C, 66.0; H, 6.3; N, 1.7. C44H49NO13 requires C, 66.1; H,
6.2; N, 1.7%); δH(CDCl3) 1.50 (3 H, s, COCH3), 2.05 (1 H, br s,
HO-6), 3.17 (1 H, m, J1,2 8.2, J2,3 11.0, J2,NH 7.0, H-2), 3.41 (3 H,
s, OCH3), 3.58 (2 H, m, H-5, Ha-6), 3.76 (3 H, s, CO2CH3), 3.90
(2 H, m, H-4, Hb-6), 4.03 (1 H, dd, J2Ј,3Ј = J3Ј,4Ј = 9.5, H-3Ј), 4.05
(2 H, m, H-4Ј, -5Ј), 4.71 (1 H, dd, J2,3 11.0, J3,4 3.2, H-3), 4.76
(1 H, d, J1Ј,2Ј 7.7, H-1Ј), 4.80 (6 H, m, 3 × CH2Ph), 4.86 (1 H, d,
J1,2 8.2, H-1), 5.29 (1 H, d, J2,NH 7.0, NH), 5.37 (1 H, dd, J1Ј,2Ј
7.7, J2Ј,3Ј 9.5, H-2Ј), and 7.0–8.0 (20 H, m, Ph); m/z 818
[M ϩ NH4]ϩ, 801 [M ϩ H]ϩ, 769 [M Ϫ OCH3]ϩ.
Sodium O-(disodium 2-O-sulfonato-ꢀ-D-glucopyranosyluronate)-
(1→3)-2-acetamido-2-deoxy-6-O-sulfonato-D-galactopyranose 1
Sodium benzyl O-(disodium 3,4-di-O-benzyl-2-O-sulfonato-ꢀ-D-
glucopyranosyluronate)-(1→3)-2-acetamido-4-O-benzyl-2-
deoxy-6-O-sulfonato-ꢀ-D-galactopyranoside 30
A solution of the benzyl ether 30 (0.44 g, 0.42 mmol) in
methanol–water (10:1, 11 cm3) was hydrogenated in the pres-
ence of 10% Pd on carbon (0.1 g) at rt under one atmosphere
pressure of hydrogen for 24 h. More water (5 cm3) was then
added, and the mixture was hydrogenated for a further 24 h.
The catalyst was removed by filtration through Celite and the
filtrate was freeze dried to give the target compound 1 (0.25 g,
96%) as a hygroscopic white foam; [α]D22 ϩ11 (c 1, equil., in water)
(Found: C, 26.1; H, 3.6; N, 2.1. C14H20NNa3O18S2ؒH2O requires
C, 26.2; H, 3.4; N, 2.2%); δH(D2O; H2O) 1.95 (3 H, s, COCH3),
3.53, 3.54 (1 H, 2 t, J2Ј,3Ј = J3Ј,4Ј = 9.5, H-3Јα,β), 3.66, 3.67 (1 H,
2 t, J3Ј,4Ј = J4Ј,5Ј = 9.5, H-4Јα,β), 3.80 (3 H, m, H-2, -5, -5Јα,β),
3.84, 3.89 (1 H, 2 dd, J2,3 11.0, J3,4 3.0, H-3α,β), 4.01, 4.03 (1 H,
2 dd, J1Ј,2Ј 7.5, J2Ј,3Ј 9.5, H-2Јα,β), 4.10 (2 H, m, H2-6α,β), 4.16,
4.22 (1 H, 2 dd, J3,4 3.0, J4,5 0.8, H-4α,β), 4.65, 4.66 (1 H, 2 d,
J1Ј,2Ј 7.5, H-1Јα,β), 4.76 (0.5 H, d, J1,2 8.0, H-1β), and 5.22 (0.5
H, d, J1,2 3.5, H-1α); δC(67.8 MHz; D2O; acetone) 22.73, 23.11
(COCH3), 52.85, 52.99 (C-2α,β), 68.10, 68.60, 68.90 (C-4,
-6α,β), 71.92, 72.21 (C-3Јα,β), 75.01, 75.12 (C-4Јα,β), 76.01,
77.49 (C-5Јα,β), 80.31, 80.61 (C-3, -2Јα,β), 91.54 (C-1α), 96.05
A solution of the ester 28 (0.62 g, 0.71 mmol) in THF (16 cm3)
was treated at 0 ЊC with hydrogen peroxide (30 wt% solution in
water; 1.8 cm3) and lithium hydroxide (1 mol dmϪ3; 3.6 cm3),
and the mixture was stirred at 0 ЊC for 1 h and at rt for
16 h, then was cooled to 0 ЊC. Methanol (10 cm3) and sodium
hydroxide (4 mol dmϪ3; 4 cm3) were then added, and the mix-
ture was stirred at rt for 6 h, then was treated with Amberlite
IR-120 (Hϩ) resin to pH 3 (pH meter control), filtered, and con-
centrated under reduced pressure. Flash silica chromatography
[dichloromethane–methanol (5:1)] afforded the corresponding
acid (484 mg, 90%) as a white powder; δH(CD3OD) 1.95 (3 H, s,
COCH3), 3.60 (1 H, dd, J5,6a 5.0, J6a,6b 10.5, Ha-6), 3.68 (1 H, dd,
J1Ј,2Ј 7.5, J2Ј,3Ј 9.5, H-2Ј), 3.70 (2 H, m, H-3Ј, -5), 3.86 (1 H, dd,
J5,6b 6.4, J6a,6b 10.5, Hb-6), 3.98 (1 H, t, J3Ј,4Ј = J4Ј,5Ј = 9.5, H-4Ј),
4.03 (1 H, d, J4Ј,5Ј 9.5, H-5Ј), 4.04 (1 H, dd, J2,3 10.3, J3,4 3.0,
H-3), 4.18 (1 H, dd, J3,4 3.0, J4,5 0.8, H-4), 4.37 (1 H, dd, J1,2 8.4,
J2,3 10.3, H-2), 4.62 (1 H, d, J1Ј,2Ј 7.5, H-1Ј), 4.67 (1 H, d, J1,2 8.4,
H-1), 4.75–5.20 (8 H, m, 4 × CH2Ph), and 7.30 (20 H, m, Ph).
A solution of the above isolated acid and the sulfur trioxide–
trimethylamine complex (1.06 g, 8 mmol) in dry DMF (10 cm3)
was stirred at 50 ЊC for 24 h. More reagent (0.7 g, 5.3 mmol)
was then added, and the mixture was stirred at 50 ЊC for a
further 48 h, then cooled. Methanol (1 cm3) was added, and the
mixture was concentrated under reduced pressure. Flash silica
(C-1β), 101.53, 101.85 (C-1Јα,β), and 175.07, 175.31 (C᎐O).
᎐
Sodium methyl O-(disodium 2-O-sulfonato-ꢀ-D-glucopyranosyl-
uronate)-(1→3)-2-acetamido-2-deoxy-6-O-sulfonato-ꢀ-D-
galactopyranoside 2
The benzyl ether 31 (0.39 g, 0.4 mmol) was hydrogenated as
2716
J. Chem. Soc., Perkin Trans. 1, 2000, 2709–2717

View Article Online
10 D. R. Miller, G. T. Anderson, J. J. Starck, J. L. Granick and
described for the preparation of 1. The filtrate was freeze dried
to afford the target compound 2 (0.24 g; 95%) as a hygroscopic
white powder; [α]D22 Ϫ15 (c 1 in water) (Found: C, 27.3; H, 3.9; N,
2.0. C15H22NNa3O18S2ؒH2O requires C, 27.5; H, 3.7; N, 2.1%);
δH(D2O; H2O) 1.92 (3 H, s, COCH3), 3.40 (3 H, s, OCH3), 3.56
(1 H, t, J2Ј,3Ј = J3Ј,4Ј = 9.5, H-3Ј), 3.66 (1 H, t, J3Ј,4Ј = J4Ј,5Ј = 9.5,
H-4Ј), 3.80 (1 H, dd, J1,2 8.0, J2,3 11.0, H-2), 3.84 (1 H, m, H-5),
3.85 (1 H, d, J4Ј,5Ј 9.5, H-5Ј), 3.88 (1 H, dd, J2,3 11.0, J3,4 3.0,
H-3), 4.01 (1 H, dd, J1Ј,2Ј 7.5, J2Ј,3Ј 9.5, H-2Ј), 4.10 (1 H, dd, J3,4
3.0, J4,5 0.8, H-4), 4.13 (2 H, m, H2-6), 4.42 (1 H, d, J1,2 8.0,
H-1), and 4.67 (1 H, d, J1Ј,2Ј 7.5, H-1Ј); δC(67.8 MHz; D2O;
acetone) 23.11 (COCH3), 51.62 (C-2), 57.78 (OCH3), 67.88
(C-4), 67.99 (C-6), 71.72 (C-4Ј), 73.03 (C-3Ј), 75.02 (C-5Ј),
80.11, 80.40 (C-3, -2Ј), 101.92 (C-1Ј), 102.96 (C-1), and 173.90,
D. Richardson, J. Clin. Oncol., 1998, 16, 3649.
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175.51 (C᎐O).
᎐
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Acknowledgements
We are grateful for support by the CNRS and the Région
Centre via a BDI studentship to N. K.
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