Synthesis of tri- and tetrasaccharide fragments of the Shigella dysenteriae type 1 O-antigen deoxygenated and fluorinated at position 3 of the methyl α-D-galactopyranoside terminus

Article abstract of DOI:10.1016/S0008-6215(98)00216-X

The blockwise synthesis of methyl alpha tri- and tetrasaccharide analogs of the biochemical repeating unit of the Shigella dysenteriae type 1 O-polysaccharide is described. Modifications include deoxygenation and deoxyfluorination at position 3 of the galactopyranoside residue. Methyl 4,6-O-benzylidene-3-deoxy-α-D-xylo-hexopyranoside (8) and methyl 4,6-O-benzylidene-3-deoxy-3-fluoro-α-D-galactopyranoside (9) were condensed with (2,3,4-tri-O-benzoyl-α-L-rhamnopyranosyl)-(1→3)-2,4-di-O-benzoyl-α-L-rhamnopyranosyl chloride to give, after deprotection, the target trisaccharide methyl α-L-rhamnopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-3-deoxy-α-D-xylo-hexopyranoside and the corresponding fluorinated oligosaccharide. For the tetrasaccharide synthesis, the glycosyl acceptors 8 and 9 were condensed with the temporarily protected (2,4-di-O-benzoyl-3-O-chloroacetyl-α-L-rhamnopyranosyl)-(1→3)-2,4-di-O-benzoyl-α-L-rhamnopyranosyl chloride. Removal of the chloroacetyl group was followed by condensation of the resulting selectively deblocked trisaccharides with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-D-glucopyranosyl chloride. Reduction and deprotection then gave the free methyl 2-acetamido-2-deoxy-α-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-3-deoxy-α-D-xylo-hexopyranoside and the fluorinated analog. Copyright (C) 1998 Elsevier Science Ltd.

Full text of DOI:10.1016/S0008-6215(98)00216-X

Carbohydrate Research 311 (1998) 121±133
Synthesis of tri- and tetrasaccharide fragments
of the Shigella dysenteriae type 1 O-antigen
deoxygenated and ¯uorinated at position 3 of
the methyl ꢀ-d-galactopyranoside terminus1
Laurence A. Mulard *, Cornelis P.J. Glaudemans
NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
Received 24 April 1998; accepted 31 July 1998
Abstract
The blockwise synthesis of methyl alpha tri- and tetrasaccharide analogs of the biochemical
repeating unit of the Shigella dysenteriae type 1 O-polysaccharide is described. Modi®cations
include deoxygenation and deoxy¯uorination at position 3 of the galactopyranoside residue.
Methyl 4,6-O-benzylidene-3-deoxy-ꢀ-d-xylo-hexopyranoside (8) and methyl 4,6-O-benzylidene-3-
deoxy-3-¯uoro-ꢀ-d-galactopyranoside (9) were condensed with (2,3,4-tri-O-benzoyl-ꢀ-l-rhamno-
pyranosyl)-(1!3)-2,4-di-O-benzoyl-ꢀ-l-rhamnopyranosyl chloride to give, after deprotection, the
target trisaccharide methyl ꢀ-l-rhamnopyranosyl-(1!3)-ꢀ-l-rhamnopyranosyl-(1!2)-3-deoxy-ꢀ-
d-xylo-hexopyranoside and the corresponding ¯uorinated oligosaccharide. For the tetrasaccharide
synthesis, the glycosyl acceptors 8 and 9 were condensed with the temporarily protected (2,4-di-O-
benzoyl-3-O-chloroacetyl-ꢀ-l-rhamnopyranosyl)-(1!3)-2,4-di-O-benzoyl-ꢀ-l-rhamnopyranosyl
chloride. Removal of the chloroacetyl group was followed by condensation of the resulting selec-
tively deblocked trisaccharides with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-ꢀ-d-glucopyranosyl chlor-
ide. Reduction and deprotection then gave the free methyl 2-acetamido-2-deoxy-ꢀ-d-gluco-
pyranosyl-(1!3)-ꢀ-l-rhamnopyranosyl-(1!3)-ꢀ-l-rhamnopyranosyl-(1!2)-3-deoxy-ꢀ-d-xylo-he-
xopyranoside and the ¯uorinated analog. # 1998 Elsevier Science Ltd. All rights reserved
Keywords: Shigella dysenteriae type 1; Deoxygenated oligosaccharides; Deoxy¯uorinated oligosaccharides
1. Introduction
especially in children. The O-speci®c polysaccharide
(O-SP) portion of its lipopolysaccharide (LPS)
interacts directly with the host. It was suggested that
immunization with the O-antigen conjugated to a
carrier protein could confer protective immunity [2].
We have studied the anity of the S. dysenteriae
type 1 O-SP for a number of monoclonal immu-
noglobulins elicited by this bacterium [3,4].
Shigella dysenteriae type 1 is common in develop-
ing countries where it causes devastating epidemics,
* Corresponding author at present address: Unite de
Chimie Organique, Dept de BGM, Institut Pasteur, 28 rue du
Dr. Roux, 75724 Paris Cedex 15, France. Fax: 1 45 68 84 04; e-
mail: lmulard@pasteur.fr
1
Part 10 of the series Synthesis of ligands related to the
O-speci®c antigen of Shigella dysenteriae type 1. For part 9 see
ref [1].
The repeating unit of the organism's O-antigen
is the tetrasaccharide I [5,6]. Recent data [3] show
0008-6215/98/$Ðsee front matter # 1998 Elsevier Science Ltd. All rights reserved
PII S0008-6215(98)00216-X

122
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
disaccharide II to be the antigenic determinant for
a monoclonal IgM and an IgG [4] antibody, but
somewhat longer fragments bearing the galacto-
pyranose unit may be needed for optimal recogni-
tion by other antibodies.
Deoxy and deoxy¯uoro sugars have been used as
probes to investigate the hydrogen bonding net-
work between carbohydrate determinants and
protein epitopes [7,8]. We reported on the con-
tribution of the various hydroxyl groups in II to
binding with a monoclonal IgM antibody [1], and
showed the 3-OH of the galactopyranosyl residue
to be critical for binding. In order to examine the
e€ect of a ¯uorine atom at C-3 of the galactopyr-
anose unit on binding of ꢀ-l-Rhap-(1!3)-ꢀ-l-
Rhap-(1!2)-ꢀ-d-Galp-OMe and of ꢀ-d-GlcpNAc-
(1!3)-ꢀ-l-Rhap-(1!3)-ꢀ-l-Rhap-(1!2)-ꢀ-d-Galp-
OMe, the trisaccharide 15 and the tetrasaccharide
29 were prepared. Their synthesis is reported here,
together with that of the corresponding deoxy-
genated derivatives 12 and 25, respectively.
debenzoylation gave the desired deoxygenated tri-
saccharide 12 (91% from 11) and its corresponding
¯uorinated trisaccharide 15 (92% from 14).
1
Experimental single bond JC-1,H-1 coupling con-
stants were 174.2 Hz (A), 171.2 Hz (B), 172.3 Hz
(C) and 176.8 Hz (A), 173.3 Hz (B), 171.8 Hz (C)
for compounds 12 and 15, respectively.
2. Results and discussion
By analogy with the preparation of compounds
12 and 15, tetrasaccharides 25 and 29 were synthe-
sized using the fully protected rhamnobiosyl chlor-
ide 6 as a common building block. In both cases,
the N-acetyl glucosamine residue was introduced
last.
For the construction of the deoxygenated targets
12 and 25, compound 8 prepared in seven steps
from methyl ꢀ-d-galactopyranoside [9], was used
as the glycosyl acceptor. By analogy, the prepara-
tion of the ¯uorinated derivatives 15 and 29
involved the use of the ¯uorinated nucleophile 9
prepared from 1,2:5,6-di-O-isopropylidene-ꢀ-d-
glucofuranose in three steps [10].
Condensation of 8 and 9 respectively with the
known [11] rhamnobiosyl chloride 7 was per-
formed under base-de®cient conditions [12]. The
use of 7 as the donor rather than the fully acety-
lated rhamnobiosyl glycosyl bromide [13] avoids
the transesteri®cation known to occur [14] with 2-
O-acetylated glycoside halides under the conditions
of silver tri¯uoromethanesulfonate mediated gly-
cosylation conditions. Thus, the fully protected
trisaccharides 10 and 13 were obtained in 88 and
92% yield, respectively. Hydrogenolysis (10!11,
92% and 13!14, 94%) followed by Zemplen
This strategy required a rhamnopyranosyl donor
4 bearing a selectively removable blocking group
[15] at position 3 with di€ering protecting groups
elsewhere. The use of the known dibenzoylated
precursor 2 [16] prevented acyl migration later
during regioselective deblocking of the chloroacetyl
group at position 3 (2!3, 89%), while allowing
anchimeric assistance when replacing the leaving
group at C-1. The chloride 4 was easily obtained by
cleavage [17] with dichloromethyl methyl ether
(DCMME) in the presence of zinc chloride (88%).
Condensation of 4 with the glycosyl acceptor 2
promoted by silver tri¯uoromethanesulfonate then
gave the methyl glycoside 5 (84%) which was con-
verted to the chloride 6 (66%) again by selective
cleavage with DCMME/ZnCl2.

L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
123
were fully deacylated under Zemplen conditions to
give the target tetrasaccharides 25 (63%) and 29
(88%), respectively. Experimental single bond
1JC-1,H-1 coupling constants were 175.1 Hz (A),
171.0 Hz (B), 172.2 Hz (C), 174.9 Hz (D) and
178.8 Hz (A), 173.3 Hz (B), 171.3 Hz (C), 174.0 Hz
(D) for compounds 25 and 29, respectively.
By analogy with the synthesis of trisaccharides
10 and 13, condensation of the glycosyl acceptors 8
and 9 with the rhamnobiosyl donor 6 was pro-
moted by silver tri¯uoromethanesulfonate under
base-de®cient conditions, to give trisaccharides 16
(80%) and 18 (74%), respectively. Selective O-
dechloroacetylation in 16 and 18, using thiourea,
a€orded both the selectively deblocked 17 (88%)
and 19 (96%). Further chain extension, took
advantage of the nonparticipating nature of the 2-
azido group during chemical glycosylation with the
chloride 20 [18] under silver tri¯uoromethane-
sulfonate promoted Koenigs±Knorr conditions.
Yields of the corresponding deoxy- (21, 69%) and
deoxy¯uoro- (26, 85%) tetrasaccharides with the
desired 1,2-cis linkage, were comparable to that of
the reference compound bearing a non-modi®ed
galactopyranoside unit [19]. The N-acetylated tet-
rasaccharides 23 and 27 were readily obtained from
the azido precursors 21 and 26 by triphenylpho-
sphine reduction of the azido moiety to the amino
group (21! 22, 79%) followed by N-acetylation
(22!23, 96% and 26!27, 71% overall yield).
Subsequent hydrogenolysis of the benzylidene
acetal gave diols 24 (99%) and 28 (89%) which
The anomeric purity of both the tri- and tetra-
saccharide glycosides was con®rmed by 13C and 1H
NMR spectroscopy. Consideration of the glycosyl
halides and reaction conditions [19] employed to
synthesize 12, 15, 25 and 29 led us to expect high
anomeric purity. Based on the observation [20] that
1
ꢀ-linked pyranoses have single bond JC-1,H-1
values &170 Hz whilst those that are ꢁ-linked
1
have JC-1,H-1&160 Hz, this is indeed the case. Sin-
gle bond JC-1,H-1 coupling constants for all four
1
compounds did con®rm the ꢀ-anomeric con®gura-
tion at all linkages.
3. Experimental
General methods.ÐMelting points were deter-
mined on a Ko¯er hot stage. Optical rotations were
measured in CHCl3 solution at 25 ꢀC, except where

124
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
indicated otherwise, with a Perkin±Elmer auto-
matic polarimeter, Model 241 MC. TLC on pre-
coated slides of Silica Gel G F254 (Analtech) was
performed with solvent mixtures of appropriately
adjusted polarity consisting of A, CH2Cl2-MeOH;
B, hexane±EtOAc; C, hexane±acetone; D, toluene±
acetone; E, toluene±EtOAc; F, water±acetonitrile.
Detection was e€ected when applicable, with UV
light, and/or by charring with 5% H2SO4 in EtOH.
Preparative chromatography was performed by
elution from columns of Silica Gel 60 (particle size
0.04±0.063 mm). Reverse phase chromatography of
compounds 25 and 29 was performed by elution
from columns of Silica gel Lichoprep RP 18 (par-
ticle size 25±40 ꢂm). The NMR spectra were
Methyl 2,4-di-O-benzoyl-3-O-chloroacetyl-a-l-
rhamnopyranoside (3).ÐA solution of chloroacetic
anhydride (31.0 g, 181.3 mmol) in DMF (30 mL)
was added dropwise to a solution of methyl 2,4-di-
O-benzoyl-ꢀ-l-rhamnopyranoside
(2)
(40.1 g,
103.9 mmol) in a mixtureꢀ of DMF (140 mL) and
pyridine (170 mL) at 45 C. After 30 min, MeOH
was added and the cooling bath was removed. The
solution was concentrated and the residue was
taken up in CH2Cl2. Extractive work-up followed
by crꢀystallization gave 3 (42.7 g, 89%); mp 98.5±
ꢀ
1
99.5 C (EtOH); [ꢀ]d +90 (c 1.0); NMR: H, ꢃ
8.11±7.41 (m, 10 H, Ph), 5.65 (dd, 1 H, J2,3 3.4, J3,4
10.1 Hz, H-3), 5.54 (m, 1 H, H-2), 5.47 (t, 1 H, J4,5
9.9 Hz, H-4), 4.84 (bs, 1 H, H-1), 4.10 (dq, 1 H, J5,6
6.6 Hz, H-5), 3.87, 3.80 (2 d, 2 H, Jgem 15.0 Hz,
CH2Cl), 3.47 (s, 3 H, OCH3), and 1.33 (d, 3 H, H-
6); 13C, ꢃ 98.5 (C-1), 70.2 (C-2), 71.5 (C-4), 71.2 (C-
3), 66.5 (C-5), 55.3 (OCH3), 40.5 (CH2Cl), and 17.6
(C-6); CIMS: m/z 480 ([M+NH4]+). Anal. Calcd
for C23H23ClO8: C, 59.69; H, 5.00. Found: C,
59.59; H, 5.03.
ꢀ
recorded at 25 C for solutions in CDCl3, unless
stated otherwise, on a Varian Gemini-300 spectro-
1
meter (300 MHz for H, 75 MHz for 13C). Internal
references: for solutions in CDCl3, CDCl3
1
(77.00 ppm for 13C) and Me4Si (0.00 ppm for H),
for solutions in D2O, CD3OD (49.00 ppm for 13C)
1
and HOD (4.78 ppm for H). Proton-signal assign-
ments were made by ®rst-order analysis of the
spectra, and were supported by homonuclear
decoupling experiments. Of the two magnetically
nonequivalent geminal protons at C-6, the one
resonating at lower ®eld is denoted H-6a and the
one at higher ®eld is denoted H-6b. The 13C NMR
assignments were made by two-dimensional
13C±1H correlation maps (HETCOR). Inter-
changeable assignments are marked with an aster-
isk in listing of signal assignments. Sugar residues
in oligosaccharides were assigned roman numerals
in ascending order starting from the one bearing
the aglycon and identi®ed by a superscript in listing
of signal assignments. Low resolution chemical
ionization mass spectra (CIMS) were obtained
using NH3 as the ionizing gas. Before use, AgOTf
2,4-Di-O-benzoyl-3-O-chloroacetyl-a-l-rhamno-
pyranosyl chloride (4).ÐA solution of compound 3
(5.0 g, 10.8 mmol) in 1,2-dichloroethane (20 mL)
was treated with ꢀ,ꢀ-dichloromethyl methyl ether
.
(DCMME, 30 mL) and ZnCl2 Et2O complex
(1.4 mL of a 2.2 M solution in CH2Cl2) at 65 ꢀC for
7 h. The solution was diluted with toluene, con-
centrated and coevaporated with toluene three
times. The residue was chromatographed (solvent
C, 12:1) to give the known 4 (4.3 g, 88%) which
NMR data were identical to those published [18].
Methyl (2,4-di-O-benzoyl-3-O-chloroacetyl-a-l-
rhamnopyranosyl)-(1!3)-2,4-di-O-benzoyl-a-l-
rhamnopyranoside (5).ÐA solution of crude 4,
prepared from 3 (16.0 g, 34.6 mmol), 2,6-di-tert-
butyl-4-methyl pyridine (4.72 g, 23.0 mmol) and
ꢀ
was dried at 133 Pa/50 C for 2 h, CH2Cl2 was
compound 2 (8.02 g, 20.8 mmol) in CH2Cl2
(150 mL) was added dropwise to a suspension of
silver tri¯uoromethanesulfonate (AgOTf, 6.42 g,
dried over drierite. Solutions in organic solvents
were dried with anhyd sodium sulfate. Methyl 2,4-
di-O-benzoyl-ꢀ-l-rhamnopyranoside (2), prepared
as described [16] was obtained in an overall yield
of 74% starting from methyl ꢀ-l-rhamnopyrano-
side [21] (34.0 g, 190 mmol). 3,4,6-Tri-O-acetyl-2-
azido-2-deoxy-ꢀ-d-glucopyranosyl chloride (20)
was prepared [22] from the corresponding ꢁ-acet-
ate, obtained as described [18]. The disaccharide
(2,3,4-tri-O-benzoyl-ꢀ-l-rhamnopyranosyl)-(1!3)-
2,4-di-O-benzoyl-ꢀ-l-rhamnopyranosyl chloride
(7) was prepared from the nucleophile 2 as
described [11].
ꢀ
25.0 mmol) in CH2Cl2 (30 mL) at 15 C. After
30 min, more base (1.02 g, 5.0 mmol) was added,
the cooling bath was removed and stirring was
continued for 2 h, at which point very little starting
material remained (TLC, solvent E, 9:1). CH2Cl2
(100 mL) was added and the mixture was ®ltered
through a bed of Celite. The ®ltrate was washed
with a 1:1 mixture of 5% aq NaHCO3 and 5% aq
Na2S2O3, then water and satd aq NaCl. The
organic phase was dried and concentrated. Chro-
matography of the residue (solvent E, 30:1) gave

L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
125
disaccharide 5 (14.38 g, 84%) as a white foam, [ꢀ]d
+130ꢀ (c 1.0); NMR: 1H, ꢃ 8.25±7.34 (m, 20 H, Ph),
5.55 (t, 1 H, J3,4 9.8, J4,5 9.8 Hz, H-4I), 5.48 (dd, 1
H, J1,2 1.7, J2,3 3.4 Hz, H-2I), 5.41 (dd, 1 H, J2,3
3.2, J3,4 10.0 Hz, H-3II), 5.29 (t, 1 H, J4,5 9.8 Hz, H-
4II), 5.15 (dd, 1 H, J1,2 1.7 Hz, H-2II), 5.12 (bs, 1 H,
H-1II), 4.89 (d, 1 H, H-1I), 4.44 (dd, 1 H, H-3I),
4.05 (m, 2 H, H-5I, 5II), 3.71, 3.67 (2 d, 2 H, Jgem
15.0 Hz, CH2Cl), 3.45 (s, 3 H, OCH3), 1.34 (d, 3 H,
J5,6 6.3 Hz, H-6I), and 1.15 (d, 3 H, J5,6 6.1 Hz, H-
6II); 13C, ꢃ 99.2 (C-1I), 98.3 (C-1II), 76.01 (C-3I),
73.2 (C-4I), 72.1 (C-2I), 71.3 (C-4II), 70.5 (C-3II),
70.1 (C-2II), 67.4 (C-5II), 66.6 (C-5I), 55.3 (OCH3),
40.3 (CH2Cl), 17.7 (C-6I), and 17.4 (C-6II); CIMS:
m/z 834 ([M+NH4]+). Anal. Calcd for C43H41
ClO14: C, 63.20; H, 5.06. Found: C, 63.30; H, 5.11.
(2,4-Di-O-benzoyl-3-O-chloroacetyl-a-l-rhamno-
pyranosyl)-(1!3)-2,4-di-O-benzoyl-a-l-rhamnopyr-
CH2Cl2 (10 mL). After 45 min, when the tempera-
ꢀ
ture of the bath was 5 C, cooling was termi-
nated. The mixture was stirred for 45 min at
ambient temperature, after which time TLC (sol-
vent D, 9:1) showed that only little of the acceptor
remained and that 7 had completely disappeared.
The mixture was ®ltered through a bed of Celite,
and processed as described for the preparation of
the disaccharide 5. The residue was chromato-
graphed (solvent D, 24:1) to a€ord 10 (1.09 g, 88%)
as an amorphous solid, [ꢀ]d +154ꢀ (c 1.0); NMR:
1H, ꢃ 8.24±7.16 (m, 30 H, Ph), 5.61 (t, partially
overlapped, 1 H, J4.5 9.8 Hz, H-4II), 5.57 (dd, par-
tially overlapped, 1 H, J2,3 3.3, J3,4 10.1 Hz, H-3III),
5.54 (s, 1 H, PhCH), 5.51 (bd, partially overlapped,
1 H, H-2II), 5.48 (t, partially overlapped, 1 H, J4,5
9.8 Hz, H-4III), 5.26 (bd, 1 H, H-2III), 5.24 (bs, 1 H,
H-1III), 5.15 (bs, 1 H, H-1II), 5.00 (d, 1 H, J1,2
3.0 Hz, H-1I), 4.52 (dd, 1 H, J3,4 9.9, J2,3 3.2 Hz, H-
3II), 4.26 (bd, partially overlapped, 1 H, J6a,6b
11.9 Hz, H-6aI), 4.20 (m, 3 H, H-2I, 4I, 5II), 4.10
(m, 2 H, H-6bI, 5III), 3.64 (bs, 1 H, H-5I), 3.50 (s, 3
H, OCH3), 2.35±2.18 (m, 2 H, H-3I), 1.35 (d, 3 H,
J5,6 6.1 Hz, H-6II), and 1.13 (d, 3 H, J5,6 6.1 Hz, H-
6III); 13C, ꢃ 101.1 (PhCH), 99.2, 99.1 (C-1I, 1III),
98.1 (C-1II), 76.6 (C-3II), 73.4 (C-4I), 73.0 (C-4II),
72.9 (C-2I), 72.6 (C-2II), 71.5 (C-4III), 70.7 (C-2III),
69.5 (C-6I), 69.3 (C-3III), 67.4 (C-5III), 67.1 (C-5II),
61.7 (C-5I), 55.2 (OMe), 29.8 (C-3I), 18.0 (C-6II),
and 17.4 (C-6III); CIMS: m/z 1096 ([M+NH4]+).
Anal. Calcd for C61H58O18: C, 67.89; H, 5.42.
Found: C, 67.88; H, 5.46.
.
anosyl chloride (6).ÐZnCl2 Et2O complex (1.1 mL
of a 2.2 M solution in CH2Cl2) was added to a
stirred solution of the methyl glycoside 5 (5.9 g,
7.2 mmol) and DCMME (60 mL) in dichloroethane
(30 mL). The mixture was stirred at 60 ꢀC for
1.25 h after which time TLC (solvent B, 9:1)
showed that only traces of the starting material
remained. The solution was diluted with toluene,
concentrated and coevaporated repeatedly with
toluene. Chromatography of the residue gave the
chloride 6 (3.9 g, 66%) as a white foam, [ꢀ]d +108ꢀ
1
(c 1.0); NMR: H, ꢃ 8.21±7.35 (m, 20 H, Ph), 6.23
(bs, 1 H, H-1I), 5.63 (m, 2 H, H-2I, 4I), 5.40 (dd, 1
H, J2,3 2.6, J3,4 10.0 Hz, H-3II), 5.31 (t, 1 H, J4,5
9.8, J4,3 9.8 Hz, H-4II), 5.17 (bs, 2 H, H-1II, 2II),
4.74 (dd, 1 H, J2,3 3.4, J3,4 10.0 Hz, H-3I), 4.34 (dq,
1 H, J5,4 9.8 Hz, H-5I), 4.05 (dq, 1 H, H-5II), 3.73,
3.67 (2 d, 2 H, Jgem 14.9 Hz, CH2Cl), 1.38 (d, 3 H,
J5,6 6.3 Hz, H-6I), and 1.15 (d, 3 H, J5,6 6.3 Hz, H-
6II); 13C, ꢃ 99.3 (C-1II), 89.5 (C-1I), 74.6 (C-3I), 74.2
(C-4I), 72.4 (C-2I), 71.1 (C-4II), 70.3 (C-3II), 69.9
(C-2II), 69.8 (C-5I), 67.6 (C-5II), 40.2 (CH2Cl), and
17.3 (2 C, C-6I, 6II); CIMS: m/z 838 ([M+NH4]+).
Anal. Calcd for C42H38Cl2O13: C, 61.39; H, 4.66;
Cl, 8.63. Found: C, 61.11; H, 4.63; Cl, 9.06.
Methyl (2,3,4-tri-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyranosyl)-
(1!2)-3-deoxy-a-d-xylo-hexopyranoside (11).Ð
A suspension of 10% Pd-C catalyst (250 mg) in a
1:2.5:17.5 mixture of AcOH:acetone:EtOH (42 mL)
containing the fully protected 10 (850 mg,
0.79 mmol) was stirred at ambient temperature,
overnight, under a hydrogen atmosphere. The sus-
pension was ®ltered through a bed of Celite and
the ®ltrate concentrated. To eliminate any residual
traces of the catalyst, the residue was chromato-
graphed on a short column of silica gel (solvent D,
3:1) to give 11 (719 mg, 92%) as an amorphous
Methyl (2,3,4-tri-O-benzoyl-a-l-rhamnopyrano-
syl-(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyranosyl)-
(1!2)-4,6-O-benzylidene-3-deoxy-a-d-xylo-hexo-
pyranoside (10).ÐA solution of the glycosyl chlor-
ide 7 [11] (1.14 g, 1.34 mmol), the glycosyl acceptor
8 (306 mg, 1.15 mmol) and 2,6-di-tert-butyl-4-
methylpyridine (295 mg, 1.44 mmol) in CH2Cl2
(20 mL) was added dropwise, at 20 ꢀC, to a
stirred suspension of AgOTf (473 mg, 1.84 mmol) in
solid, [ꢀ]d +153ꢀ (c 1.0); NMR: H, ꢃ 8.24±7.16
1
(m, 25 H, Ph), 5.59 (t, partially overlapped, 1 H,
J4,5 10.0 Hz, H-4II), 5.57 (dd, partially overlapped,
1 H, J2,3 3.4, J3,4 10.1 Hz, H-3III), 5.50 (bd, par-
tially overlapped, 1 H, H-2II), 5.48 (t, partially
overlapped, 1 H, J4,5 10.0 Hz, H-4III), 5.26 (dd, 1
H, J1,2 1.7 Hz, H-2III), 5.24 (bs, 1 H, H-1III), 5.15

126
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
(d, 1 H, J1,2 1.4 Hz, H-1II), 4.93 (d, 1 H, J1,2 3.2 Hz,
H-1I), 4.51 (dd, 1 H, J3,4 9.8, J2,3 3.4 Hz, H-3II),
4.22 (dq, partially overlapped, 1 H, H-5II), 4.17 (m,
partially overlapped, 2 H, H-2I, 4I), 4.09 (dq, par-
tially overlapped, 1 H, H-5III), 3.90 (bs, 2 H, H-6I),
3.74 (t, 1 H, J5,6a 3.1, J5,6b 3.1 Hz, H-5I), 3.45 (s, 3
H, OCH3), 3.15 (bs, 1 H, OH), 2.07 (m, 2 H, H-3I),
1.35 (d, 3 H, J5,6 6.3 Hz, H-6II), and 1.12 (d, 3 H,
J5,6 6.3 Hz, H-6III); 13C, ꢃ 99.1 (C-1III), 98.9 (C-1I),
98.2 (C-1II), 76.4 (C-3II), 73.0 (2 C, C-2I, 4II), 72.6
(C-2II), 71.5 (C-4III), 70.7 (C-2III), 69.4 (C-3III),
69.0 (C-4I), 68.5 (C-5I), 67.4 (C-5III), 67.2 (C-5II),
64.1 (C-6I), 55.5 (OMe), 32.1 (C-3I), 18.0 (C-6II),
and 17.4 (C-6III); CIMS: m/z 1008 ([M+NH4]+).
Anal. Calcd for C54H54O18: C, 65.45; H, 5.49.
Found: C, 65.48; H, 5.53.
chloride 7 [11] (1.1 g, 1.30 mmol), the glycosyl
acceptor 9 (284 mg, 1.0 mmol) and 2,6-di-tert-
butyl-4-methylpyridine (287 mg, 1.4 mmol) in
CH2Cl2 (20 mL) was added dropwise, at 20 ꢀC, to
a stirred suspension of AgOTf (461 mg, 1.8 mmol)
in CH2Cl2 (10 mL). Cooling was terminated after
30 min, after which time TLC (solvent D, 19:1)
showed that no starting material remained. The
mixture was processed as described for the pre-
paration of the disaccharide 5, and the crude pro-
duct was chromatographed (solvent E, gradient) to
a€ord 13 (1.01 g, 92%) which crystallized on
ꢀ
standing, mp 130±131 C (EtOH); [ꢀ]d +172ꢀ (c
1.0); NMR: 1H, ꢃ 8.24±7.16 (m, 30 H, Ph), 5.64 (m,
1 H, H-2II), 5.59 (m, 2 H, H-4II, CHPh), 5.58 (dd,
partially overlapped, 1 H, J3,2 3.2 Hz, H-3III), 5.49
(t, 1 H, J3,4 10, J4,5 9.5 Hz, H-4III), 5.28 (dd, 1 H,
H-2III), 5.25 (m, 2 H, H-1II, 1III), 5.06 (t, partially
overlapped, 1 H, J1,F 3.9 Hz, H-1I), 4.95 (ddd,
partially overlapped, 1 H, J2,3 9.9, J3,4 3.7, J3,F
48.5 Hz, H-3I), 4.55 (dd, 1 H, J2,3 3.2, J3,4 9.8 Hz,
H-3II), 4.50 (bt, 1 H, J4,F 4.7 Hz, H-4I), 4.36 (dt,
partially overlapped, 1 H, J1,2 3.5, J2,F 10.1 Hz, H-
2I), 4.31 (bd, partially overlapped, 1 H, J6a,6b
12.2 Hz, H-6aI), 4.22±4.13 (m, 2 H, H-5II, 5III), 4.11
(bd, 1 H, H-6bI), 3.71 (bs, 1 H, H-5I), 3.47 (s, 3 H,
OCH3), and 1.36, 1.15 (2 d, 6 H, J5,6 6.1, J5,6
6.1 Hz, H-6II, 6III); 13C, ꢃ 100.8 (PhCH), 99.9 (d,
J1,F 11.2 Hz, C-1I), 99.1 (2 C, C-1II, 1III), 87.2 (d,
J3,F 191.1, C-3I), 76.0 (C-3II), 75.3 (d, J2,F 17.2 Hz,
C-2I), 74.8 (d, 16.0 Hz, C-4I), 73.1 (C-4II), 72.0 (C-
2II), 71.5 (C-4III), 70.7 (C-2III), 69.4 (C-3III), 69.1
(C-6I), 67.5, 67.4 (C-5II, 5III), 62.0 (d, J5,F 5.8 Hz,
C-5I), 55.6 (OMe), and 18.02, 17.4 (C-6II, 6III); 19F,
Methyl a-l-rhamnopyranosyl-(1!3)-a-l-rhamno-
pyranosyl-(1!2)-3-deoxy-a-d-xylo-hexopyranoside
(12).ÐA solution of 11 (560 mg, 0.56 mmol) in
MeOH (5 mL) was treated with M methanolic
MeONa (500 ꢂL) and the solution was stirred at
room temperature overnight. After neutralization
with Amberlite IR-120 (H+), and evaporation of
the solvent, the crude product was chromato-
graphed (solvent A) to give pure 12 (228 mg, 86%)
as a white amorphous solid; [ꢀ]d 26ꢀ (c 1.0,
1
water); NMR: H (D2O), ꢃ 5.03 (bs, 1 H, J1,2
II II
I
I
1.7 Hz, H-1III), 4.88 (m, 2 H, J1 ,2 1.9, J1 ,2
3.4 Hz, H-1II, 1I), 4.08 (m, 1 H, J4,5 1.4 Hz, H-4I),
4.06 (dd, 1 H, J2,3 3.3 Hz, H-2II), 4.04 (m, 1 H, H-
2I), 4.02 (dd, 1 H, J2,3 3.5 Hz, H-2III), 3.84 (m, 1 H,
H-5I), 3.83 (dd, 1 H, H-3II), 3.80 (m, 1 H, H-3III),
3.79 (m, 1 H, H-5III), 3.78 (m, 1 H, J4.5 9.6 Hz, H-
5II), 3.72 (dd, 1 H, J5,6a 4.4 Hz, H-6aI), 3.68 (dd, 1
H, J5,6b 7.8, J6a,6b 11.7 Hz, H-6bI), 3.53 (t, 1 H, J3,4
9.7 Hz, H-4II), 3.47 (s, 3 H, OCH3), 3.45 (t, 1 H,
J4,5 9.6, J3,4 9.7 Hz, H-4III), 2.07 (ddd, 1 H, J2,3a
12.5, J3a,3b 13.6, J3a,4 3.0 Hz, H-3aI), 1.93 (ddd, 1
H, J2,3b 5.1, J3b,4 3.4 Hz, H-3bI), 1.32 (d, 3 H, J5,6
6.3 Hz, H-6II), and 1.28 (d, 3 H, J5,6 6.3 Hz, H-6III);
13C, ꢃ 103.4 (C-1III, JC,H 172.3 Hz), 101.1 (C-1II,
JC,H 171.2 Hz), 89.1 (C-1I, JC,H 174.3 Hz), 79.2 (C-
3II), 73.0 (C-4III), 72.2 (C-4II), 72.0 (C-2I), 71.5 (C-
5I), 71.1 (3 C, C-3III, 2II, 2III), 70.1 (C-5II), 70.0 (C-
5III), 66.8 (C-4I), 62.4 (C-6I), 65.6 (OMe), 31.9 (C-
3I), 17.7 (C-6III), and 17.5 (C-6II); CIMS: m/z 488
ꢃ
46.13 (m, 1 F, JF,3 48.5, JF,4 5.1, JF,2 9.9 Hz, F-
3I); CIMS: m/z 1114 ([M+NH4]+). Anal. Calcd
for C61H57FO18: C, 66.79; H, 5.24; F, 1.73. Found:
C, 66.81; H, 5.43; F, 1.58.
Methyl (2,3,4-tri-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!2)-3-deoxy-3-¯uoro-a-d-galactopyranoside
(14).ÐA solution of the fully protected trisacchar-
ide 13 (788 mg, 0.72 mmol) in a 1:5 mixture of
ꢀ
water:AcOH (6 mL) was stirred at 65 C for 6 h.
Concentration of the solution and chromatography
of the residue (solvent D, 4:1) gave 14 (679 mg,
94%) as a white amorphous solid, [ꢀ]d +168ꢀ (c
([M+NH4]+). Anal. Calcd for C19H34O13 0.5
.
1
H2O: C, 47.60; H, 7.36. Found: C, 47.47; H, 7.33.
Methyl (2,3,4-tri-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyranosyl)-
(1!2)-4,6-O-benzylidene-3-deoxy-3-¯uoro-a-d-gal-
actopyranoside (13).ÐA solution of the glycosyl
1.0); NMR: H, ꢃ 8.24±7.18 (m, 25 H, Ph), 5.61
(dd, partially overlapped, 1 H, H-2II), 5.60 (t, par-
tially overlapped, 1 H, H-4II), 5.58 (dd, partially
overlapped, 1 H, J3,2 3.2, J3,4 10.1 Hz, H-3III), 5.48
(t, 1 H, J4,5 9.9 Hz, H-4III), 5.28 (dd, 1 H, J1,2

L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
127
1.7 Hz, H-2III), 5.26 (bs, 1 H, H-1III*), 5.21 (d, 1 H,
J1,2 1.5 Hz, H-1II*), 4.98 (t, 1 H, J1,F 3.9 Hz, H-1I),
4.85 (ddd, 1 H, J2,3 9.8, J3,4 3.4, J3,F 49.5 Hz, H-3I),
4.54 (dd, 1 H, J2,3 3.4, J3,4 9.7 Hz, H-3II), 4.33 (dd,
1 H, J4,F 6.6 Hz, H-4I), 4.24 (dt, partially over-
lapped, 1 H, J1,2 3.5, J2,F 11.2 Hz, H-2I), 4.24±4.11
(m, 2 H, H-5II, 5III), 4.31 (bd, partially overlapped,
1 H, J6a,6b 12.2 Hz, H-6aI), 4.11 (bd, 1 H, H-6bI),
3.71 (bs, 1 H, H-5I), 3.43 (s, 3 H, OCH3), and 1.35,
1.13 (2 d, 6 H, J5,6 6.1, J5,6 6.1 Hz, H-6II, 6III); 13C,
ꢃ 99.4 (d, J1,F 8.5 Hz, C-1I), 99.2 (C-1II), 99.1 (C-
1III), 89.0 (d, J3,F 183.6, C-3I), 76.1 (C-3II), 75.6 (d,
J2,F 16.8 Hz, C-2I), 73.0 (C-4II), 72.1 (C-2II), 71.5
(C-4III), 70.7 (C-2III), 69.5 (d, J4,F 18.8 Hz, C-4I),
69.3 (C-3III), 68.6 (d, J5,F 5.2 Hz, C-5I), 67.5, 67.4
(C-5II, 5III), 62.8 (C-6I), 55.4 (OMe), and 17.9, 17.4
(C-6II, 6III); 19F, ꢃ 41.40 (m, 1 F, JF,3 49.4, JF,4
5.0, JF,2 10.9 Hz, F-3I); CIMS: m/z 1026
H2O: C, 44.27; H, 7.04; F, 3.68. Found: C, 44.54;
H, 7.14; F, 3.64.
Methyl (2,4-di-O-benzoyl-3-O-chloroacetyl-a-l-
rhamnopyranosyl-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-
deoxy-a-d-xylo-hexopyranoside (16).ÐA solution
of the glycosyl chloride 6 (3.50 g, 4.26 mmol), the
glycosyl acceptor 8 (755 mg, 2.83 mmol) and 2,6-di-
tert-butyl-4-methylpyridine (805 mg, 3.92 mmol) in
CH2Cl2 (50 mL) was added with stirring, at 15 ꢀC,
to a suspension of AgOTf (1.29 g, 5.02 mmol) in
CH2Cl2 (30 mL). Stirring was continued for 1.5 h,
after which time the bath temperature had reached
ꢀ
0 C. TLC (9:1 toluene±EtOAc) showed the com-
plete disappearance of 8. The mixture was pro-
cessed as described for the preparation of 5, and
the crude product was chromatographed (solvent
E, 16:1) to give pure 16 (2.39 g, 80%) as a white
foam, together with a slightly contaminated frac-
tion (300 mg, 10%) which could be used directly,
([M+NH4]+). Anal. Calcd for C45H53FO18 0.5
.
H2O: C, 63.71; H, 5.34; F, 1.86. Found: C, 63.93;
H, 5.36; F, 1.56.
[ꢀ]d +110ꢀ (c 1.0); NMR: H, ꢃ 8.21±7.35 (m, 25
1
Methyl a-l-rhamnopyranosyl-(1!3)-a-l-rhamno-
pyranosyl-(1!2)-3-deoxy-3-¯uoro-a-d-galactopyr-
anoside (15).ÐA solution of 14 (532 mg,
0.52 mmol) in MeOH (5 mL) was treated with M
methanolic sodium methoxide (500 ꢂL) as descri-
bed for the preparation of 12. Chromatography of
the crude material (solvent A) gave pure 15
(230 mg, 88%) as a white amorphous solid; [ꢀ]d
H, Ph), 5.57 (t, partially overlapped, 1 H, J4,5
10.0 Hz, H-4II), 5.54 (s, 1 H, CHPh), 5.49 (bs, 1 H,
H-2II), 5.42 (dd, 1 H, J2,3 2.9, J3,4 10.0 Hz, H-3III),
5.30 (t, 1 H, J4,5 9.8 Hz, H-4III), 5.15 (m, 3 H, H-
1II, 1III, 2III), 5.00 (bs, 1 H, H-1I), 4.49 (dd, 1 H,
J3,4 9.7, J3,2 2.9 Hz, H-3II), 4.27±4.03 (m, 6 H, H-2I,
4I, 6I, 5II, 5III), 3.70 (bs, 2 H, CH2Cl), 3.63 (bs, 1 H,
H-5I), 2.31±2.17 (m, 2 H, H-3I), and 1.34, 1.15 (2 d,
6 H, J5,6 6.1, J5,6 6.1 Hz, H-6II, 6III); 13C, ꢃ 101.0
(PhCH), 99.1 (2 C, C-1II, 1III), 98.1 (C-1I), 76.2 (C-
3II), 73.3 (C-4I), 73.1 (C-4II), 72.9 (C-2I), 72.4 (C-
2II), 71.2 (C-4III), 70.4 (C-3III), 70.2 (C-2III), 69.5
(C-6I), 67.4 (C-5II), 67.0 (C-5III), 61.7 (C-5I), 55.2
(OMe), 40.3 (CH2Cl), 29.7 (C-3I), and 17.90, 17.3
(C-6II, 6III); CIMS: m/z 1068 ([M+NH4]+). Anal.
Calcd for C56H55ClO18: C, 63.97; H, 5.27; Cl, 3.37.
Found: C, 64.00; H, 5.31; Cl, 3.34.
Methyl (2,4-di-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyrano-
syl)-(1!2)-4,6-O-benzylidene-3-deoxy-a-d-xylo-
hexopyranoside (17).ÐA solution of the fully pro-
tected 16 (2.39 g, 2.27 mmol), thiourea (800 mg,
10.51 mmol) and sym-collidine (300 ꢂL, 2.27 mmol)
in a 1:1 mꢀixture CH2Cl2±MeOH (30 mL) was stir-
red at 25 C for 36 h. More CH2Cl2 (70 mL) was
added and stirring was continued for 15 min. The
resulting suspension was ®ltered through a bed of
Celite. The ®ltrate was extracted with ice-cold 5%
aq HCl, 5% aq NaHCO3, water, dried and con-
centrated. Column chromatography (solvent E,
9:1) of the residue a€orded 17 as an amorphous
41ꢀ (c 1.0, water); NMR: H (D2O), ꢃ 5.27 (d, 1
1
H, J1,2 1.7 Hz, H-1III), 4.99 (dd, 1 H, J1,2 4.0 Hz, H-
1I), 4.94 (d, 1 H, J1,2 1.8 Hz, H-1II), 4.81 (ddd, 1 H,
J2,3 10.0, J3,4 3.5, J3,F 49.0 Hz, H-3I), 4.29 (ddd, 1
H, J4,5 1.1 Hz, H-4I), 4.14 (ddd, 1 H, H-2I), 4.12
(dd, 1 H, J2,3 3.4 Hz, H-2II), 4.07 (dd, 1 H, J2,3
3.4 Hz, H-2III), 3.84 (m, 3 H, H-3II, 3III, 5III*), 3.80
(m, 2 H, J5,6a 5.0 Hz, H-5I, 6aI), 3.75 (dd, 1 H, J5,6b
7.2, J6a,6b 11.7 Hz, H-6bI), 3.73 (m, 1 H, H-5II*),
3.55 (t, 1 H, J3,4 9.7, J4.5 9.6 Hz, H-4II), 3.45 (t, 1
H, J3.4 9.7, J4,5 9.6 Hz, H-4III), 3.44 (s, 3 H, OCH3),
1.33 (d, 3 H, J5,6 6.3 Hz, H-6II), and 1.29 (d, 3 H,
J5,6 6.1 Hz, H-6III); 13C, ꢃ 103.3 (C-1III, JC,H
171.8 Hz), 102.9 (C-1II, JC,H 173.3 Hz), 99.7 (d, J1,F
10.3, JC,H 176.8 Hz, C-1I), 91.1 (d, J3,F 183.2 Hz,
C-3I), 79.0 (C-3II), 75.4 (d, J2,F 17.2 Hz, C-2I), 73.0
(C-4III), 72.2 (C-4II), 71.2 (C-2III), 71.1 (C-3III),
70.9 (d, J3,F 6.4 Hz, C-5I), 70.8 (C-2II), 70.4 (C-
5III*), 70.0 (C-5II*), 68.5 (d, J4,F 17.1 Hz, C-4I),
61.8 (C-6I), 55.9 (OMe), 17.8 (C-6II), and 17.6 (C-
6III); 19F, ꢃ 39.95 (m, 1 F, JF,3 49.0, JF,4 7.4, JF,2
11.5, JF,1 4.0 Hz, F-3I); CIMS: m/z 506
([M+NH4]+). Anal. Calcd for C19H33FO13 0.5
.

128
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
solid (1.95 g, 88%), [ꢀ]d +93ꢀ (c 1.0); NMR data:
1H, ꢃ 8.18±7.15 (m, 25 H, Ph), 5.54 (t, partially
overlapped, 1 H, J4,5 9.9 Hz, H-4II), 5.53 (s, par-
tially overlapped, 1 H, CHPh), 5.48 (dd, 1 H, J1,2
1.7 Hz, H-2II), 5.20, 5.12 (2 d, 2 H, J1,2 1.0, J1,2
1.0 Hz, H-1II, 1III), 5.06 (t, 1 H, J3,4 9.8, J4,5 9.8 Hz,
H-4III), 4.98 (m, 2 H, H-1I, 2III), 4.45 (dd, 1 H, J3,4
10.0, J3,2 3.3 Hz, H-3II), 4.25 (bd, 1 H, J6a,6b
13.0 Hz, H-6aI), 4.19±4.15 (m, 3 H, H-2I*, 6bI, 5II),
4.08 (bd, partially overlapped, 1 H, H-4I*), 4.06
(m, partially overlapped, 1 H, H-3III), 3.95 (dq, 1
H, H-5III), 3.63 (bs, 1 H, H-5I), 3.49 (s, 3 H, OMe),
2.24±2.14 (m, 2 H, H-3I), 1.32 (d, 3 H, J5,6 6.3 Hz,
H-6II), and 1.09 (d, 3 H, J5,6 6.2 Hz, H-6III); 13C, ꢃ
101.0 (PhCH), 99.2, 98.1 (C-1II, 1III), 99.1 (C-1I),
76.6 (C-3II), 75.1 (C-4III), 73.4 (C-4I), 73.0 (3 C, C-
2I, 4II, 2III), 72.6 (C-2II), 69.5 (C-6I), 68.5 (C-3III),
67.1, 67.0 (C-5II, 5III), 61.7 (C-5I), 55.2 (OMe), 29.7
(C-3I), 17.9 (C-6II), and 17.4 (C-6III); CIMS: m/z
992 ([M+NH4]+). Anal. Calcd for C54H54O17: C,
66.52; H, 5.58. Found: C, 66.59; H, 5.62.
10.1 Hz, H-2I), 4.28 (bd, 1 H, J6a,6b 12.5 Hz, H-
6aI), 4.23±4.13 (m, 2 H, H-5II, 5III), 4.07 (bd, 1 H,
H-6bI), 3.72 (d, 1 H, Jgem 15.0 Hz, CH2Cl), 3.67
(bs, partially overlapped, 1 H, H-5I), 3.66 (d, par-
tially overlapped, 1 H, CH2Cl), 3.46 (s, 3 H,
OCH3), and 1.36, 1.17 (2 d, 6 H, J5,6 6.2, J5,6
6.2 Hz, H-6II, 6III); 13C, ꢃ 100.6 (PhCH), 99.9 (d,
J1,F 9.1 Hz, C-1I), 99.1, 99.0 (2 C, C-1II, 1III), 87.8
(d, J3,F 192.4 Hz, C-3I), 75.6 (C-3II), 75.3 (d, J2,F
16.9 Hz, C-2I), 74.6 (d, J4,F 15.1 Hz, C-4I), 73.1 (C-
4II), 71.8 (C-2II), 71.2 (C-3III), 70.4 (C-4III), 70.1
(C-2III), 68.9 (C-6I), 67.3, 67.2 (C-5II, 5III), 61.9 (d,
J5,F 5.7 Hz, C-5I), 55.4 (OMe), 40.1 (CH2Cl), and
17.7, 17.1 (C-6II, 6III); CIMS: m/z 1086
([M+NH4]+). Anal. Calcd for C56H54ClFO18: C,
62.89; H, 5.09; Cl, 3.32; 1.78. Found: C, 62.86; H,
5.16; Cl, 3.67; F, 1.51.
Methyl (2,4-di-O-benzoyl-a-l-rhamnopyranosyl)-
(1!3)-(2,4-di-O-benzoyl-a-l-rhamnopyranosyl)-
(1!2)-4,6-O-benzylidene-3-deoxy-3-¯uoro-a-d-gal-
actopyranoside
(19).Ðsym-Collidine
(33 mL,
Methyl (2,4-di-O-benzoyl-3-O-chloroacetyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-deoxy-
3-¯uoro-a-d-galactopyranoside (18).ÐA solution of
the glycosyl chloride 6 (1.50 g, 1.83 mmol), the gly-
cosyl acceptor 9 (398 mg, 1.40 mmol) and 2,6-di-
tert-butyl-4-methylpyridine (400 mg, 1.95 mmol) in
CH2Cl2 (40 mL) was added dropwise, at 15 ꢀC, to
a stirred suspension of AgOTf (610 mg, 2.37 mmol)
in CH2Cl2 (15 mL). The mixture was stirred until it
reached 5 ꢀC, at which time the cooling bath was
0.25 mmol) was added to a solution of the fully
protected 18 (270 mg, 0.25 mmol) and thiourea
(96 mg, 1.25 mmol) in 1:1 of CH2Cl2±MeOH
(8 mL). The homogenous solution was stirred at
ambient temperature for 48 h. A large excess of
CH2Cl2 (50 mL) was added and the resulting pre-
cipitate was collected on a bed of Celite. The ®l-
trate was washed with 5% aq NaHCO3, water and
satd NaCl, dried, and chromatographed (solvent
C, 2.5:1) to give 19 (241 mg, 96%) as an amor-
phous solid, [ꢀ]d +119 (c 1.0); NMR: H, ꢃ 8.20±
7.34 (m, 25 H, Ph), 5.60 (dd, 1H, J1,2 1.9, J2,3
3.2 Hz, H-2II), 5.59 (s, partially overlapped, 1 H,
PhCH), 5.55 (t, partially overlapped, 1 H, J3,4 10.0,
J4,5 9.8 Hz, H-4II), 5.21 (bs, 2 H, H-1II, 1III), 5.07
(t, partially overlapped, 1 H, J4,5 9.8, J3,4 9.8 Hz,
H-4III), 5.04 (bt, partially overlapped, 1 H, J1,F 3.6,
J1,2 3.6 Hz, H-1I), 5.00 (dd, 1 H, J1,2 1.8, J2,3
3.2 Hz, H-2III), 4.94 (ddd, partially overlapped, 1
H, J2,3 10.0, J3,4 3.7 Hz, H-3I), 4.50 (dd, partially
overlapped, 1 H, J2,3 3.2, J3,4 9.7 Hz, H-3II), 4.49
(m, 1 H, H-4I), 4.36 (dt, partially overlapped, 1 H,
J1,2 3.6, J2,F 10.2 Hz, H-2I), 4.30 (bd, partially
overlapped, 1 H, J6a,6b 12.6 Hz, H-6aI), 4.16 (dq,
partially overlapped, 1 H, J4,5 9.7 Hz, H-5II), 4.08
(m, 2 H, H-6bI, 3III), 4.01 (dq, partially overlapped,
1 H, J4,5 9.6 Hz, H-5III), 3.70 (bs, partially over-
lapped, 1 H, H-5I), 3.46 (s, 3 H, OCH3), 2.17 (d, 1
H, J3,OH 7.8 Hz, OH-3III), 1.33 (d, 3 H, J5,6 6.3 Hz,
H-6II), and 1.12 (d, 3 H, J5,6 6.1 Hz, H-6III); 13C, ꢃ
100.7 (PhCH), 99.9 (d, J1,F 9.4 Hz, C-1I), 99.0 (2 C,
ꢀ
1
ꢀ
removed. Stirring was continued for 1 h at 25 C.
TLC (solvent E, 9:1) showed the complete dis-
appearance of 9 and the presence of one major
compound together with some minor ones of close
chromatographic mobility to that of 18. The sus-
pension was ®ltered through a bed of Celite, and
the ®ltrate was treated as described for the pre-
paration of 5. Chromatography of the residue
(solvent C, 3.5:1) gave 18 (1.11 g, 74%) as an
amorphous solid, [ꢀ]d +131ꢀ (c 1.0); NMR: H, ꢃ
1
8.22±7.33 (m, 25 H, Ph), 5.63 (m, 1 H, H-2II), 5.59
(m, partially overlapped, 1 H, J3,4 10.2, J4,5 9.5 Hz,
H-4II), 5.59 (s, partially overlapped, 1 H, PhCH),
5.44 (dd, 1 H, J3,2 2.7, J3,4 10.0 Hz, H-3III), 5.33 (t,
1 H, J4,5 9.8 Hz, H-4III), 5.24 (bs, 1 H, H-1II), 5.18
(bs, 2 H, H-1III, 2III), 5.06 (bt, partially overlapped,
1 H, J1,F 3.9 Hz, H-1I), 4.95 (ddd, partially over-
lapped, 1 H, J2,3 10.0, J3,4 3.7, J3,F 48.6 Hz, H-3I),
4.55 (dd, 1 H, J2,3 3.2, J3,4 9.7 Hz, H-3II), 4.47 (bt, 1
H, J4,F 4.6 Hz, H-4I), 4.36 (dt, 1H, J1,2 3.5, J2,F

L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
129
C-1II, 1III), 87.8 (d, J3,F 191.3 Hz, C-3I), 76.0 (C-
3II), 75.3 (d, J2,F 16.7 Hz, C-2I), 75.1 (C-4III), 74.8
(d, J4,F 15.7 Hz, C-4I), 73.1 (C-2II), 73.0 (C-4II),
72.1 (C-2II), 69.1 (C-6I), 68.5 (C-3III), 67.3, 67.0 (C-
5II, 5III), 62.0 (d, J5,F 5.5 Hz, C-5I), 55.6 (OMe),
and 18.0, 17.4 (C-6II, 6III); CIMS: m/z 1010
([M+NH4]+). Anal. Calcd for C54H53FO17: C,
65.31; H, 5.38; F, 1.91. Found: C, 65.25; H, 5.43;
F, 2.40.
(C-3II), 73.3 (d, C-4I), 73.1 (C-4II), 73.0 (C-3III),
72.3 (C-2II), 71.8 (2 C, C-2III, 4III), 70.2 (C-3IV),
69.5 (C-6I), 67.8 (C-2III), 67.5 (C-4IV), 67.3 (C-5III),
67.2 (C-5II), 67.0 (C-5IV), 61.7 (C-5I), 60.9 (C-6IV),
60.3 (C-2IV), 55.1 (OMe), 29.7 (C-3I), 20.6, 20.5,
20.3 (C(O)CH3), 17.9 (C-6II), and 17.4 (C-6III);
CIMS: m/z 1305 ([M+NH4]+). Anal. Calcd for
C66H69N3O24: C, 61.53; H, 5.40; N, 3.26. Found:
C, 61.35; H, 5.45; N, 3.16.
Methyl (3,4,6-tri-O-acetyl-2-azido-2-deoxy-a-d-
glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-
deoxy-a-d-xylo-hexopyranoside (21).ÐA solution
of the glycosyl acceptor 17 (370 mg, 0.35 mmol),
the chloride [22] 20 (200 mg, 0.57 mmol) and 2,6-di-
tert-butyl-4-methylpyridine (100 mg, 0.48 mmol) in
CH2Cl2 (15 mL) was added dropwise to a suspen-
sion of AgOTf (160 mg, 0.62 mmol) in CH2Cl2
(5 mL) at 10 ꢀC. The reaction mixture was stirred
Methyl (3,4,6-tri-O-acetyl-2-amino-2-deoxy-a-d-
glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)- 4,6-O-benzylidene-3-
deoxy-a-d-xylo-hexopyranoside (22).ÐA mixture
of the azido tetrasaccharide 21 (200 mg, 0.15 mmol)
and triphenylphosphine (203 mg, 0.77 mmol) in
CH2Cl2 (10 mL) was heated for 24 h at 35 ꢀC.
Water (0.5 mL) was added and stirring was main-
tained at the same temperature for another 24 h.
The organic phase was separated from the the aq
one, dried and concentrated. Chromatography of
the residue (solvent D, 4.5:1) a€orded the amino
derivative 22 as an amorphous solid (155 mg,
ꢀ
at 0 C for 1 h and then overnight at ambient tem-
perature. Although some of the glycosyl acceptor
17 subsisted in the mixture, the donor 20 was
completely consumed. CH2Cl2 was added and the
mixture was ®ltered through a bed of Celite.
Treatment was proceeded as described for the pre-
paration of the disaccharide 5. The residue was
chromatographed (solvent E, 12:1) to give pure
starting material 17 (54 mg, 15%) eluting ®rst and
21 (285 mg, 69% based on the consumed nucleo-
phile) as an amorphous solid, [ꢀ]d +157ꢀ (c 1.0);
79%); [ꢀ]d +146ꢀ (c 1.0); NMR: H, ꢃ 8.19±7.34
1
(m, 25 H, Ph), 5.53 (m, 2 H, J4,5 9.8 Hz, H-4II,
PhCH), 5.49 (dd, 1 H, J1,2 1.6 Hz, H-2II), 5.30 (t, 1
H, J3,4 9.6 Hz, H-4III), 5.17 (dd, 1 H, J2,3 2.8 Hz, H-
2III), 5.14 (s, 1 H, H-1II), 5.08 (d, 1 H, J1,2 1.0 Hz,
H-1III), 4.98 (bt, 1 H, J1,2 3.1 Hz, H-1I), 4.65 (dd, 1
H, J3,4 9.3, J4,5 10.2 Hz, H-4IV), 4.58 (dd, 1 H, J2,3
10.0 Hz, H-3IV), 4.51 (d, 1 H, J1,2 3.4 Hz, H-1IV),
4.46 (dd, 1 H, J2,3 3.4, J3,4 10.0 Hz, H-3II), 4.24 (d,
1 H, J6a,6b 12.9 Hz, H-6aI), 4.19 (m, 3 H, H-2I, 4I,
5II), 4.10 (dd, partially overlapped, 1 H, J2,3 3.1 Hz,
H-3III), 4.07 (d, partially overlapped, 1 H, J5,6b
1.5 Hz, H-6bI), 4.00 (dq, 1 H, J4,5 9.8 Hz, H-5III),
3.69 (dd, 1 H, J5,6 3.1, J6a,6b 12.3 Hz, H-6aIV), 3.63
(bs, 1 H, H-5I), 3.48 (s, 3 H, OCH3), 3.44 (m, 2 H,
H-5IV, 6bIV), 2.58 (dd, 1 H, J2,3 9.7 Hz, H-2IV),
2.17 (m, 2 H, H-3I), 2.01, 1.87, 1.58 (3 s, 9 H,
OAc), 1.33 (d, 3 H, J5,6 6.1 Hz, H-6II), and 1.12 (d,
3 H, J5,6 6.1 Hz, H-6III); 13C, ꢃ 101.0 (PhCH), 99.2
(d, C-1III), 99.1 (C-1I), 98.2 (C-1II), 96.0 (C-1IV),
76.1 (C-3II), 73.8 (C-3IV), 73.3 (C-2I*), 73.1 (C-4II),
73.0 (C-4I*), 72.3 (C-2II), 71.9 (C-4III), 71.2 (C-
3III), 69.5 (C-6I), 68.0 (C-2III), 67.8 (C-4IV), 67.3
(C-5IV), 67.2 (C-5III), 61.7 (C-5I), 61.2 (C-6IV), 55.1
(OMe), 53.9 (C-2IV), 29.7 (C-3I), 20.7, 20.6, 20.3
(OAc), 17.8 (C-6II), and 17.3 (C-6III); CIMS: m/z
1262 ([M+H]+). Anal. Calcd for C66H71NO24: C,
62.80; H, 5.67; N, 1.11. Found: C, 62.82; H, 5.92;
N, 0.95.
1
NMR: H, ꢃ 8.19±7.15 (m, 25 H, Ph), 5.47 (s,
overlapped, 1 H, PhCH), 5.46 (dd, overlapped, 1
H, J3,4 9.7, J4,5 9.3 Hz, H-4II), 5.44 (dd, 1 H, J1,2
1.7, J2,3 3.3 Hz, H-2II), 5.27 (dd, 1 H, J3,4 10, J4,5
9.8 Hz, H-4III), 5.10 (bs, 1 H, H-1III), 5.07 (bd, J2,3
3.0 Hz, H-2III), 5.02 (d, 1 H, J1,2 1.2 Hz, H-1II),
4.92 (d, 1 H, J1,2 2.9 Hz, H-1I), 4.97 (ddd, 1 H, J3,4
9.7 Hz, H-3IV), 4.65 (dd, 1 H, J4,5 9.5 Hz, H-4IV),
4.52 (d, 1 H, J1,2 3.5 Hz, H-1IV), 4.41 (dd, 1 H, H-
3II), 4.20 (dd, 1 H, J6a,6b 12.3, J5,6a 3.1 Hz, H-6aI),
4.15 (m, partially overlapped, 1 H, H-5II), 4.10 (dd,
1 H, J3,4 9.8 Hz, H-3III), 4.03±3.98 (m, 3 H, H-2I,
4I, 6bI), 3.92 (dq, 1 H, J5,6 6.3 Hz, H-5III), 3.68 (dd,
1 H, J5,6a 3.3, J6a,6b 12.4 Hz, H-6aIV), 3.56 (bs, 1 H,
H-5I), 3.46 (dt, partially overlapped, 1 H, H-5IV),
3.42 (s, 3 H, OMe), 3.38 (dd, 1 H, J5,6b 1.9 Hz, H-
6bIV), 2.94 (dd, 1 H, J2,3 10.5 Hz, H-2IV), 2.14±2.00
(m, 2 H, H-3I), 1.94, 1.80, 1.54 (3 s, 9 H, OAc),
1.27 (d, 3 H, J5,6 6.1 Hz, H-6II), and 1.04 (d, 3 H,
J5,6 6.1 Hz, H-6III); 13C, ꢃ 101.0 (PhCH), 99.1
(C-1III), 99.0 (C-1I), 98.2 (C-1II), 93.9 (C-1IV), 76.2

130
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
Methyl (2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-
of acetic acid±EtOH (25 mL) and the suspension
was stirred in a H2 atmosphere overnight. TLC
(solvent D, 2.2:1) showed that the reaction was
complete and a single product was formed. Filtra-
tion on a bed of Celite followed by elution on a
short column of silica gel to remove any residual
catalyst a€orded the di-hydroxylated 24 in theore-
a-d-glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-
deoxy-a-d-xylo-hexopyranoside (23).ÐA mixture
of the azido tetrasaccharide 21 (700 mg, 0.54 mmol)
and triphenylphosphine (715 mg, 2.73 mmol) in
CH2Cl2 (30 mL) was heated for 24 h at 35 ꢀC.
Water (2 mL) was added and stirring was main-
tained at the same temperature for another 24 h.
The organic phase was separated from the the
aqueous one, dried and concentrated. The residue
was taken up in pyridine (5 mL) and acetic anhy-
dride (2.5 mL) was added. The mixture was stirred
at ambient temperature overnight. Conventional
processing and chromatography of the residue
gave the N-acetylated product 23 (678 mg, 96%) as
an amorphous solid; [ꢀ]d +136ꢀ (c 1.0); NMR: 1H,
ꢃ 8.18±7.33 (m, 25 H, Ph), 5.53 (s, 1 H, H-4II,
PhCH), 5.51 (dd, 1 H, J3,4 9.7, J4,5 9.8 Hz, H-4II),
5.49 (dd, 1 H, J1,2 1.8, J2,3 3.3 Hz, 1 H, H-2II), 5.26
(t, 1 H, J4,5 9.8, J3,4 9.9 Hz, H-4III), 5.09 (m, 3 H,
H-1II, 1III, 2III), 4.97 (d, 1 H, J1,2 3.2 Hz, H-1I),
4.83 (dd, 1 H, J3,4 9.7, J4,5 9.8 Hz, H-4IV), 4.58 (dd,
1 H, J2,3 10.4 Hz, H-3IV), 4.44 (dd, 1 H, J2,3 3.3,
J3,4 9.9 Hz, H-3II), 4.46 (dd, 1 H, J1,2 3.6 Hz, H-
1IV), 4.24 (d, 1 H, J6a,6b 12.7 Hz, H-6aI), 4.19 (m, 2
H, H-2I, 4I), 4.07 (dd, 1 H, J5,6b 2.0 Hz, H-6bI),
4.03 (m, 3 H, J2,3 3.2 Hz, H-5II, 3III, 2IV), 3.98 (dq,
1 H, H-5III), 3.66 (dd, 1 H, J5,6a 3.0, J6a,6b 12.7 Hz,
H-6aIV), 3.63 (bs, 1 H, H-5I), 3.48 (s, 3 H, OCH3),
3.43 (dt, 1 H, H-5IV), 3.39 (dd, 1 H, J5,6b 1.9 Hz, H-
6bIV), 2.17 (m, 2 H, H-3I), 2.01, 1.87, 1.58 (3 s, 9 H,
OAc), 1.33 (d, 3 H, J5,6 6.1 Hz, H-6II), and 1.12 (d,
3 H, J5,6 6.1 Hz, H-6III); 13C, ꢃ 101.0 (PhCH), 99.0
(2 C, C-1I, 1III*), 98.2 (C-1II*), 95.6 (C-1IV), 76.3
(C-3II), 73.3 (C-4II), 73.1 (C-2I*), 72.9 (C-3III, 4I*),
72.2 (C-2II), 72.0 (C-4III), 70.9 (C-3IV), 69.5 (C-6I),
68.6 (C-2III), 67.6 (C-5IV), 67.4 (C-5III), 67.1 (C-
5II), 67.0 (C-4IV), 61.6 (C-5I), 60.8 (C-6IV), 55.1
(OMe), 50.8 (C-2IV), 29.7 (C-3I), 22.2 (NHAc),
20.7, 20.6, 20.3 (3 C, OAc), 17.9 (C-6II), and 17.4
(C-6III); CIMS: m/z 1321 ([M+NH4]+). Anal.
Calcd for C68H73NO25: C, 62.62; H, 5.64; N, 1.08.
Found: C, 62.56; H, 5.69; N, 1.03.
tical yield; [ꢀ]d +141ꢀ (c 1.0); NMR: H, ꢃ 8.19±
1
7.15 (m, 20 H, Ph), 5.51 (dd, partially overlapped,
1 H, J3,4 9.3, J4,5 10.4 Hz, H-4II), 5.50 (dd, partially
overlapped, 1 H, J2,3 2.8 Hz, H-2II), 5.26 (t, 1 H,
J4,5 9.8, J3,4 9.8 Hz, H-4III), 5.09 (bd, 3 H, H-1II,
1III, 2III), 4.92 (d, 1 H, J1,2 3.2 Hz, H-1I), 4.83 (dd, 1
H, J3,4 9.8, J4,5 9.6 Hz, H-4IV), 4.58 (dd, 1 H, J2,3
10.3 Hz, H-3IV), 4.45 (dd, 1 H, J2,3 3.4, J3,4 9.9 Hz,
H-3II), 4.41 (d, 1 H, J1,2 3.5 Hz, H-1IV), 4.20 (dq, 1
H, J4,5 9.9, J5,6 6.3 Hz, H-5II), 4.16 (m, 2 H, H-2I,
4I), 4.05 (m, 2 H, H-3III, 2IV), 3.97 (dq, 1 H, H-
5III), 3.89 (bd, 2 H, H-6I), 3.73 (bs, 1 H, H-5I), 3.65
(dd, 1 H, J6a,6b 12.4, J5,6a 2.8 Hz, H-6aIV), 3.45 (s, 3
H, OCH3), 3.41 (m, 1 H, H-5IV), 3.40 (d, 1 H, H-
6bIV), 2.05 (m, 2 H, H-3I), 2.00, 1.83, 1.60 (3 s, 9 H,
OAc), 1.33 (d, 3 H, H-6II), 1.32 (s, 3 H, NHAc),
and 1.11 (d, 3 H, J5,6 6.1 Hz, H-6III); 13C, ꢃ 100.1
(C-1III*), 99.0 (C-1I), 98.4 (C-1II*), 95.6 (C-1IV),
76.3 (C-3II), 73.1 (2 C, C-2II, 3III), 73.0 (C-2I), 72.3
(C-4II), 72.1 (C-4III), 71.0 (C-3IV), 68.8 (C-4I), 68.6
(C-5I), 68.5 (C-2III), 67.6 (C-5IV), 67.4 (C-5III), 67.1
(C-4IV), 67.0 (C-5II), 64.0 (C-6I), 60.9 (C-6IV), 55.0
(OMe), 50.8 (C-2IV), 32.0 (C-3I), 22.1 (NHAc),
20.7, 20.6, 20.3 (OAc), 17.8 (C-6II), and 17.3 (C-
6III); CIMS: m/z 1233 ([M+NH4]+). Anal. Calcd
for C61H69NO25: C, 60.24; H, 5.72; N, 1.15.
Found: C, 60.11; H, 5.83; N, 1.07.
Methyl (2-acetamido-2-deoxy-a-d-glucopyrano-
syl)-(1!3)-a-l-rhamnopyranosyl-(1!3)-a-l-rham-
nopyranosyl-(1!2)-3-deoxy-a-d-xylo-hexopyrano-
side (25). A solution of 24 (180 mg, 0.14 mmol) in
MeOH (5 mL) was treated with 0.5 M methanolic
MeONa (500 ꢂL) as described for the preparation
of 12. Reverse phase chromatography of the crude
material (solvent F) followed by lyophilisation gave
pure 25 (61 mg, 63%) as a white amorphous solid;
[ꢀ]d +51ꢀ (c 0.9, water); H NMR data (D2O):
1
5.07 (d, 1 H, J1,2 3.4 Hz, H-1IV), 5.06 (s, 1 H, H-
1III), 4.89 3.76 (m, 7.5 H, 0.5 H-2IV, 3III, 3II, 5III,
5I, 3IV, 6aIV, 6bIV), 3.75±3.65 (m, 3 H, H-5II, 6aI,
6bI), 3.59±3.50 (m, 3 H, H-5IV, 4II, 4III), 3.48 (s, 3
H, OCH3), 2.11 (m, 1 H, J3a,3b 13.3, J2,3a 3.8, J3a,4
3.8 Hz, H-3aI), 2.06 (s, 3 H, C(=O)CH3), 1.93
(ddd, 1 H, J2,3b 11.1, J3b,4 1.7 Hz, H-3bI), and 1.33,
1.32 (2 d, 6 H, J5,6 6.2 Hz, H-6II, 6III); 13C: ꢃ 175.2
Methyl (2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-
a-d-glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-3-deoxy-a-d-xylo-hexo-
pyranoside (24).Ð10% Palladium-on-charcoal
catalyst (200 mg) was added to a solution of the
N-acetylated 23 (310 mg, 24 ꢂmol) in a 1:4 mixture

L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
131
(C=O), 102.9 (C-1III, JC,H 172.2 Hz), 100.9 (C-1II,
JC,H 171.0 Hz), 99.0 (C-1I, JC,H 175.1 Hz), 95.1 (C-
1IV, JC,H 174.9 Hz), 79.1 (C-3II), 76.0 (C-3III), 72.6
(C-4IV), 72.0 (C-4II), 71.9 (C-2I), 71.7 (C-3IV), 71.4
(C-5I), 71.1 (C-4III), 70.9 (C-2II), 70.5 (C-5IV), 70.0
(2 C, C-5II, 5III), 67.6 (C-2III), 66.7 (C-4I), 62.2
(C-6I), 61.0 (C-6IV), 55.4 (OCH3), 54.4 (C-2IV),
31.7 (C-3I), 22.7 (C(=O)CH3), and 17.6, 17.5 (C-
6II, 6III); m/z 674 ([M+ H]+). Anal. Calcd for
C27H47NO18: C, 45.31; H, 7.38; N, 1.90. Found: C,
45.17; H, 7.11; N, 1.88.
H-5I), 3.53 (dt, 1 H, H-5IV), 3.46 (s, 3 H, OCH3),
3.44 (dd, 1 H, J5,6b 2.0 Hz, H-6bIV), 3.01 (dd, 1 H,
J2,3 10.5, J1,2 3.7 Hz, H-2IV), 2.00, 1.86, 1.60 (3 s, 9
H, OAc), 1.33 (d, 3 H, J5,6 6.3 Hz, H-6II), and 1.15
(d, 3 H, J5,6 6.1 Hz, H-6III); 13C NMR: ꢃ 100.9
(PhCH), 99.9 (d, J1,F 9.2 Hz, C-1I), 99.3, 99.1
(C-1II, 1III), 93.9 (C-1IV), 88.25 (d, J3,F 191.2 Hz,
C-3I), 75.6 (C-3II), 75.4 (d, J2,F 17.0 Hz, C-2I), 74.8
(d, J4,F 16.0 Hz, C-4I), 73.2 (C-2II), 71.8 (3 C, C-2II,
3III, 4III) 70.3 (C-3IV), 69.1 (C-6I), 67.8 (C-2III),
67.5 (C-4IV), 67.3 (2 C, C-5II, 5III), 67.2 (C-5IV),
62.0 (d, J5,F 5.7 Hz, C-5I), 55.6 (OMe), 20.6, 20.5,
20.3 (OAc), 17.8 (C-6II), and 17.3 (C-6III); CIMS:
m/z 1323 ([M+NH4]+). Anal. Calcd for
C66H68FN3O24: C, 60.69; H, 5.25; F, 1.45; N, 3.22.
Found: C, 60.71; H, 5.28; F, 1.10; N, 3.14.
Methyl (3,4,6-tri-O-acetyl-2-azido-2-deoxy-a-d-
glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-
deoxy-3-¯uoro-a-d-galactopyranoside
(26).ÐA
solution of the glycosyl acceptor 19 (550 mg,
0.51 mmol), the crude chloride 20 (314 mg,
0.90 mmol) and 2,6-di-tert-butyl-4-methylpyridine
(164 mg, 0.80 mmol) in CH2Cl2 (15 mL) was added
dropwise to a suspension of AgOTf (257 mg,
1.0 mmol) in CH2Cl2 (5 mL) under sꢀtirring at
Methyl (2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-
a-d-glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-4,6-O-benzylidene-3-
deoxy-3-¯uoro-a-d-galactopyranoside
(27).Ð
Hydrolysis, followed by N-acetylation, of the
azido tetrasaccharide 26 (600 mg, 0.45 mmol) was
performed as described for the preparation of the
deoxygenated 23. Chromatography of the residue
(solvent C, 2:1) gave the pure tetrasaccharide 27
(440 mg, 71%) as an amorphous solid, together
with a second fraction slightly contaminated by
triphenylphosphine (230 mg). Data for 27 are as
ꢀ
10 C. Stirring was maintained at 5 C for 1 h
and then overnight when the cooling bath reached
a ®nal temperature of 15 ꢀC. Although some of the
glycosyl acceptor 19 subsisted, the reaction mixture
had remained unchanged during this period.
Dichloromethane was added and the mixture was
®ltered through a bed of Celite. Processing fol-
lowed that described for the preparation of the
disaccharide 5. The residue was chromatographed
(solvent D, 19:1) to ®rst give pure starting material
19 (195 mg, 35%) and 26 (370 mg, 85% based on
the consumed nucleophile) as an amorphous solid,
follows; [ꢀ]d +139ꢀ (c 1.0); NMR: H, ꢃ 8.17±7.14
1
(m, 25 H, Ph), 5.62 (bs, 1 H, H-2II), 5.58 (s, 1 H,
PhCH), 5.52 (t, 1 H, J3,4 9.9, J4,5 9.8 Hz, H-4II),
5.27 (t, 1 H, J4,5 9.8, J3,4 9.8 Hz, H-4III), 5.17 (bs, 1
H, H-1II), 5.11 (m, 2 H, H-1III, 2III), 5.04 (bt, par-
tially overlapped, 1 H, J1,F 5.1 Hz, H-1I), 4.92
(ddd, partially overlapped, 1 H, J3,F 48.4, J2,3 9.8,
J3,4 3.8 Hz, H-3I), 4.82 (dd, 1 H, J4,5 9.8 Hz, H-4IV),
4.68 (dd, 1 H, J3,4 9.7, J2,3 10.0 Hz, H-3IV), 4.50
(dd, partially overlapped, 1 H, J2,3 3.5, J3,4 9.5 Hz,
H-3II), 4.49 (m, 1 H, H-4I), 4.42 (d, 1 H, J1,2
3.4 Hz, H-1IV), 4.33 (ddd, partially overlapped, 1
H, J1,2 3.7, J2,F 10.1 Hz, H-2I), 4.31 (dd, partially
overlapped, 1 H, J6a,6b 12.9 Hz, H-6aI), 4.16 (dq,
partially overlapped, 1 H, J4,5 10.0, J5,6 6.4 Hz, H-
5II), 4.11 (dd, 1 H, J5,6b 1.3 Hz, H-6bI), 4.07 (m,
partially overlapped, 2 H, J2,3 3.2 Hz, H-3III, 5III),
3.69 (bs, 1 H, H-5I), 3.66 (dd, partially overlapped,
1 H, J5,6a 2.0 Hz, H-6aIV), 3.45 (s, 3 H, OCH3),
3.44 (m, 1 H, H-5IV), 3.42 (dd, 1 H, J6a,6b 12.6 Hz,
H-6bIV), 1.99, 1.83, 1.60 (3 s, 9 H, OAc), 1.33 (d, 3
H, J5,6 6.3 Hz, H-6II), 1.32 (s, 3 H, NHAc), and
1.15 (d, 3 H, J5,6 6.1 Hz, H-6III); 13C, ꢃ 100.7
[ꢀ]d +174ꢀ (c 0.9); NMR: H, ꢃ 8.19±7.34 (m, 25
1
H, Ph), 5.63 (dd, 1H, J1,2 1.8, J2,3 3.2 Hz, H-2II),
5.59 (s, 1 H, PhCH), 5.54 (t, 1 H, J3,4 9.9, J4,5
9.8 Hz, H-4II), 5.07 (t, 1 H, J4,5 9.8, J3,4 10.0 Hz, H-
4III), 5.21 (bs, 3 H, H-1II, 1III, 2III), 5.04 (bt,
partially overlapped, 1 H, J1,F 4.9, J1,2 3.7 Hz,
H-1I), 4.93 (dd, 1 H, J3,4 9.3 Hz, H-3IV), 4.94 (ddd,
partially overlapped, 1 H, J3,F 44.5, J2,3 9.8, J3,4
3.7 Hz, H-3I), 4.71 (dd, 1 H, J4,5 10.0 Hz, H-4IV),
4.62 (d, 1 H, J1,2 3.6 Hz, H-1IV), 4.50 (dd, partially
overlapped, 1 H, J2,3 3.5, J3,4 9.9 Hz, H-3II), 4.49
(m, 1 H, H-4I), 4.34 (ddd, partially overlapped, 1
H, J1,2 3.6, J2,F 10.2 Hz, H-2I), 4.30 (dd, partially
overlapped, 1 H, J5,6a 1.7, J6a,6b 12.5 Hz, H-6aI),
4.17 (dq, partially overlapped, 1 H, J4,5 9.8 Hz, H-
5II), 4.10 (dd, 1 H, J5,6b 1.3 Hz, H-6bI), 4.07 (m,
partially overlapped, 2 H, H-3III, 5III), 3.76 (dd, 1
H, J5,6a 3.2, J6a,6b 12.4 Hz, H-6aIV), 3.70 (bs, 1 H,

132
L.A. Mulard, C.P.J. Glaudemans/Carbohydrate Research 311 (1998) 121±133
(PhCH), 99.9 (d, J1,F 8.9 Hz, C-1I), 99.2 (C-1II),
99.0 (C-1III), 95.5 (C-1IV), 87.2 (d, J3,F 191.6 Hz, C-
3I), 75.7 (C-3II), 75.4 (d, J2,F 17.1 Hz, C-2I), 74.7 (d,
J4,F 15.9 Hz, C-4I), 73.2 (C-4II), 72.8 (C-3III), 72.0
(C-4III), 71.7 (C-2II), 71.0 (C-3IV), 69.0 (C-6I), 68.5
(C-2III), 67.6 (C-5IV), 67.4 (C-5III), 67.2 (C-5II),
67.1 (C-4IV), 62.0 (d, J5,F 5.7 Hz, C-5I), 60.8 (C-
6IV), 55.6 (OMe), 50.8 (C-2IV), 22.2 (NHAc), 20.6,
20.4 (3 C, OAc), 17.8 (C-6II), and 17.3 (C-6III);
CIMS: m/z 1339 ([M+NH4]+). Anal. Calcd for
C68H72FNO25: C, 61.77; H, 5.48; F, 1.44; N, 1.06.
Found: C, 61.87; H, 5.57; F, 1.26; N, 0.88.
N, 1.13. Found: C, 59.34; H, 6.02; F, 1.68; N, 0.99.
Methyl (2-acetamido-2-deoxy-a-d-glucopyrano-
syl)-(1!3)-a-l-rhamnopyranosyl-(1!3)-a-l-
rhamnopyranosyl-(1!2)-3-deoxy-3-¯uoro-a-d-gal-
actopyranoside (29).ÐA solution of 28 (180 mg,
0.15 mmol) in MeOH (5 mL) was treated with
0.5 M methanolic sodium methoxide (500 ꢂL) as
described for the preparation of 12. Reverse phase
chromatography of the crude material (solvent F)
followed by lyophilisation gave pure 29 (89 mg,
88%) as a white amorphous solid; [ꢀ]d +72ꢀ (c 1.0,
1
water); H NMR data (D2O) ꢃ 5.07 (bs, over-
Methyl (2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-
a-d-glucopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!3)-(2,4-di-O-benzoyl-a-l-
rhamnopyranosyl)-(1!2)-3-deoxy-3-¯uoro-a-d-gal-
actopyranoside (28).Ð(a) The ¯uorinated tetra-
saccharide 27 (360 mg, 0.27 mmol) was hydro-
genolyzed as described for the preparation of 24.
Chromatography (solvent D, 2.3:1) of the residue
gave the dihydroxylated 28 (300 mg, 89%) as an
amorphous solid; [ꢀ]d +143ꢀ (c 1.0); NMR data:
1H, ꢃ 8.17±7.14 (m, 20 H, Ph), 5.61 (dd, partially
overlapped, 1 H, J2,3 4.4 Hz, H-2II), 5.51 (t, 1 H,
J3,4 9.8, J4,5 9.8 Hz, H-4II), 5.27 (t, 1 H, J4,5 9.8, J3,4
9.8 Hz, H-4III), 5.15 (s, 1 H, H-1II), 5.11 (bd, 2 H,
H-1III, 2III), 4.96 (dd, 1 H, J1,2 3.7, J1,F 3.9 Hz, H-
1I), 4.83 (dd, 1 H, J3,4 9.7, J4,5 9.9 Hz, H-4IV), 4.82
(ddd, 1 H, J3,F 49.6, J2,3 9.7, J3,4 3.3 Hz, H-3I), 4.68
(dd, 1 H, J2,3 10.5 Hz, H-3IV), 4.47 (dd, 1 H, J2,3
3.2, J3,4 9.8 Hz, H-3II), 4.42 (d, 1 H, J1,2 3.4 Hz, H-
1IV), 4.32 (m, 1 H, H-4I), 4.22 (ddd, 1 H, partially
overlapped, J1,2 3.6, J2,F 11.1 Hz, H-2I), 4.14 (dq,
partially overlapped, 1 H, J4,5 10.6, J5,6 6.3 Hz, H-
5II), 4.08 (m, 2 H, H-5III, 2IV), 4.04 (dd, 1 H, J2,3
3.1 Hz, H-3III), 3.93 (m, 2 H, H-6I), 3.82 (bs, 1 H,
H-5I), 3.65 (dd, 1 H, J6a,6b 12.3, J5,6a 2.8 Hz, H-
6aIV), 3.42 (m, 5 H, H-5IV, 6bIV, OCH3), 3.00 (bs, 1
H, OH-4I), 2.49 (bs, 1 H, OH-6I), 1.93 (m, 2 H, H-3I),
2.00, 1.83, 1.60 (3 s, 9 H, OAc), 1.32 (d, 3 H, H-6II),
1.32 (s, 3 H, NHAc), and 1.12 (d, 3 H, J5,6 6.1 Hz,
H-6III); 13C, ꢃ 99.3 (2 C, J1,F 6.4 Hz, C-1I, 1II*),
98.9 (C-1III*), 95.4 (C-1IV), 89.7 (d, J3,F 185 Hz, C-
3I), 75.8 (C-3II), 75.7 (d, J2,F 19.4 Hz, C-2I), 73.1
(C-4II), 72.8 (C-3III), 72.3 (C-4II), 72.0 (C-4III), 71.8
(C-2II), 69.3 (d, J4,F 17.0 Hz, C-4I), 68.6 (d, J5,F
7.8 Hz, C-5I), 68.5 (C-2III), 67.6 (C-5IV), 67.4 (C-
5III), 67.3 (C-5II), 67.1 (C-4IV), 62.6 (C-6I), 60.9 (C-
6IV), 55.4 (OMe), 50.8 (C-2IV), 32.0 (C-3I), 22.2
(NHAc), 20.7, 20.6, 20.3 (OAc), 17.8 (C-6II), and
17.4 (C-6III); CIMS: m/z 1251 ([M+NH4]+). Anal.
Calcd for C61H68FNO25: C, 59.36; H, 5.55; F, 1.54;
lapped, 1 H, H-1III), 5.06 (d, partially overlapped,
1 H, J1,2 3.5 Hz, H-1IV), 5.00 (dd, 1 H, J1,F 4.1 Hz,
H-1I), 4.95 (d, 1 H, J1,2 1.5 Hz, H-1II), 4.82 (ddd, 1
H, J2,3 9.9, J3,4 3.5, J3,F 48.2 Hz, H-3I), 4.28 (dd, 1
H, J4,F 7.5 Hz, H-4I), 4.20 (dd, 1 H, J1,2 2.0, J2,3
3.0 Hz, H-2III), 4.14 (ddd, partially overlapped, 1
H, J2,F 21.5, J1,2 4.0 Hz, H-2I), 4.13 (dd, 1 H, J2,3
4.0 Hz, H-2II), 4.02±3.74 (m, 12 H, H-2IV, 3IV, 4IV,
6aIV, 6bIV, 5I, 6aI, 6bI, 3II, 5II, 3III, 5III), 3.55 (m,
overlapped, 1 H, H-5IV), 3.54 (dd, partially over-
lapped, 1 H, J4,5 9.7, J3,4 9.6 Hz, H-4II), 3.53 (t,
partially overlapped, 1 H, J3,4 9.7, J4,5 9.7 Hz, H-
4III), 3.43 (s, 3 H, OCH3), 2.06 (s, 3 H, Ac), 1.33 (d,
3 H, J5,6 6.2 Hz, H-6II), and 1.32 (d, 3 H, J5,6
6.2 Hz, H-6III); 13C: ꢃ 175.2 (C=O), 102.9 (C-1III,
JC,H 171.3 Hz), 102.7 (C-1II, JC,H 173.3 Hz), 99.5
(d, J1,F 9.9 Hz, C-1I, JC,H 168.8 Hz), 95.1 (C-1IV,
JC,H 174.0 Hz), 91.0 (d, J3,F 173.2 Hz, C-3I), 78.9
(C-3II), 76.0 (C-3III), 75.1 (d, J2,F 17.3 Hz, C-2I),
72.6 (C-4IV), 71.9 (C-4II), 71.7 (C-3IV), 70.7 (d, J5,F
5.9 Hz, C-5I), 70.5 (2 C, C-2II, 5IV), 70.2 (C-5II),
70.0 (C-5III), 68.3 (d, J4,F 16.6 Hz, C-4I), 67.6 (C-
2III), 61.6 (C-6IV), 61.0 (C-6I), 55.7 (OCH3), 54.4
(C-2IV), and 17.5, 17.4 (C-6II, 6III); CIMS: m/z
692 ([M+H]+). Anal. Calcd for C27H46FNO18
.
3.5H2O: C, 42.97; H, 7.07; N, 1.85. Found: C,
42.93; H, 6.97; N, 1.76.
Acknowledgements
The authors thank Mr. J. Ughetto-Monfrin
(Unite de Chimie Organique, Institut Pasteur) for
recording the NMR spectra of the deprotected
materials.
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