Synthesis of β-D-GlcpNAc-(1→3)-α-L-Rhap-(1→2)-[β-L-Xylp- (1→4)]-α-L-Rhap-(1→3)-α-L-Rhap, the repeating unit of the O-antigen produced by Pseudomonas solanacearum ICMP 7942

Article abstract of DOI:10.1016/S0008-6215(02)00358-0

An efficient synthesis of β-D-GlcpNAc-(1→3)-α-L-Rhap-(1→2)-[β-L-Xylp- (1→4)]-α-L-Rhap-(1→3)-α-L-Rhap, the repeating unit of the O-antigen produced by Pseudomonas solanacearum ICMP 7942 and its isomer β-D-GlcpNAc-(1→3)-α-L-Rhap-(1→4)-[β-L-Xylp- (1→2)]-α-L-

Full text of DOI:10.1016/S0008-6215(02)00358-0

Carbohydrate Research 338 (2003) 19–27
www.elsevier.com/locate/carres
Synthesis of b-
D
-GlcpNAc-(1“3)-a-
L
-Rhap-(1“2)-
[b-
L
-Xylp-(1“4)]-a-
L
-Rhap-(1“3)-a- -Rhap, the repeating unit of
L
the O-antigen produced by Pseudomonas solanacearum ICMP 7942
Jianjun Zhang, Fanzuo Kong*
Research Center for Eco-En6ironmental Sciences, Academia Sinica, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, PR China
Received 15 July 2002; accepted 23 September 2002
Abstract
An efficient synthesis of b-
unit of the O-antigen produced by Pseudomonas solanacearum ICMP 7942 and its isomer b-
[b- -Xylp-(1“2)]-a- -Rhap-(1“3)-a- -Rhap was achieved via sequential assembly of the building blocks, allyl 2,3-O-isopropyli-
dene-a- -rhamnopyranoside (2), allyl 3,4-O-isopropylidene-a- -rhamnopyranoside (3), allyl 2,4-di-O-benzoyl-a- -rhamno-
pyranoside (6), 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b- -glucopyranosyl trichloroacetimidate (7), and 2,3,4-tri-O-benzoyl-b-L-
D
-GlcpNAc-(1“3)-a-
L
-Rhap-(1“2)-[b-
L
-Xylp-(1“4)]-a-
L
-Rhap-(1“3)-a-
L
-Rhap, the repeating
D
-GlcpNAc-(1“3)-a-
L
-Rhap-(1“4)-
L
L
L
L
L
L
D
xylopyranosyl trichloroacetimidate (12). The process was carried out in a regio- and stereoselective manner using glycosyl
trichloroacetimidates as donors and unprotected or partially protected rhamnopyranosides as acceptors in the presence of a
catalytic amount of trimethylsilyl trifluoromethanesulfonate (TMSOTf). © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Oligosaccharide; Rhamnose; Glucosamine
1. Introduction
antigen consisting of more than one type of repeating
unit.5 Synthesis of these compounds and their isomers
can help to provide a detailed knowledge of the chemi-
cal behavior and the structure–bioactivity relationships
among these oligosaccharides.
It was reported that the repeating unit of O-antigen
produced by Pseudomonas solanacearum ICMP 7942 is
a branched pentasaccharide with a backbone consisting
of one b-
a b- -Xylp group attached as a side chain to one of the
a-
-Rhap residues:1
D
-GlcpNAc and three a-L-Rhap residues, and
Rhamnose-containing oligosaccharides are widely
distributed in natural products, such as triterpenoid
glycosides,6 K-antigens,7 and a series of phenolic glycol-
ipids from mycobacteria.8 Synthesis of these target
compounds will need orthogonal masking groups and
multiple protection–deprotection steps if traditional
stepwise methods9,10 are used. Our previous work on
regio- and stereoselective syntheses of rhamnans re-
vealed that very high 3-selectivity was achieved when
unprotected rhamnose residue was used as acceptor,
and good 2-selectivity was obtained when a rhamnose
residue with 2,3-free OH groups was the acceptor,11,12
As part of our ongoing research project on the synthe-
sis of rhamnans, we present herein the synthesis of the
well-defined GlcpNAc-containing rhamnan pentasac-
charide and its isomer.
L
L
Pseudomonas solanacearum is a phytopathogenic,
gram-negative microorganism having many heteroge-
neous biological and biochemical properties.2–4 Each of
the P. solanacearum strains is characterized by an O-
* Corresponding author. Tel.: +86-10-62936613; fax.: +
86-10-62923563
E-mail address: fzkong@mail.rcees.ac.cn (F. Kong).
0008-6215/03/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(02)00358-0

20
J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
2. Results and discussion
ppm (dd, J1,2 1.8, J2,3 3.7) for H-2, and 5.28 ppm (dd,
3,4=J4,5=9.7) for H-4, respectively. Deallylation with
J
As shown in Scheme 1, condensation of 3,4,6-tri-O-ace-
PdCl2, followed by trichloroacetimidation with CCl3CN
in the presence of DBU or K2CO3,13 gave the disaccha-
ride donor 11. It is known that 4,6-O-isopropylidena-
tion of glucose, mannose and their glycosides is
efficiently achieved in DMF using 2-methoxypropene in
the presence of TsOH.14 However, reaction of allyl
ramnoside under the same conditions surprisingly gave
tyl-2-deoxy-2-phthalimido-b-
chloroacetimidate (7) with unprotected allyl a-
rhamnopyranoside (1) selectively gave allyl 3,4,6-tri-O-
acetyl-2-deoxy-2-phthalimido-b- -glucopyranosyl-(1
“3)-a- -rhamnopyranoside (8) in satisfactory yield
D-glucopyranosyl
tri-
L-
D
L
(59.5%). Keeping the temperature below −20 °C dur-
ing the addition of TMSOTf was necessary in order to
avoid byproduct formation. The (1“3)-linkage was
confirmed by benzoylation of 8 to give 9, whereby the
1H NMR spectrum of 9 showed characteristic signals at
l 4.31 ppm (dd, J2,3 3.7, J3,4 9.8) for H-3 and l 5.51
allyl 3,4-O-isopropylidene-a-
the main product, rather than 2,3-O-isopropylidene-a-
-rhamnopyranoside (2). The structure of 3 was con-
firmed by acetylation to give allyl 2-O-acetyl-3,4-O-
isopropylidene-a- -rhamnopyranoside (4), showing
L-rhamnopyranoside (3) as
L
L
Scheme 1. Conditions and reagents: (a) 2-methoxypropene, p-TsOH, DMF (25 mL), rt, 2 h; 30.3% for 2; 62.3% for 3; (b)
Ac2O–Pyridine (dry); 82.4% for 4; 80.1% for 15; 83.3% for 18; (c) i: AcCl–CH2Cl2, Pyridine–CH2Cl2 0 °C to rt, 2 h; ii: BzCl, rt,
12 h; 79.3% for two steps; (d) 3% CH3COCl–methanol, rt, 12–14 h; 87.9%; (e) TMSOTf, CH2Cl2; 81.9% for 19; 71.4% for 23;
88.8% for 26; 85.2% for 30; (f) BzCl–Pyridine (dry); 59.5% from 1; (g) PdCl2, 90% HOAc–NaOAc, rt, 12 h; 94.0% for 10; 87.7%
for 21; (h) CCl3CN, DBU, CH2Cl2 8 h; 88.9% for 11; 80.3% for 22; 66.8% for 29 from 27; (i) 90% TFA, rt, 2 h; 82.7% for 14;
83.2% for 17; (j) i: EtOH–10% hydrazine hydrate, reflux, 48 h; ii: Ac2O–Pyridine (dry), rt, 12 h; 78.7% for 24 for two steps; 81.8%
for 31 for two steps; (k) satd NH3–MeOH, rt, 72 h; 80.4% for 25; 82.8% for 32.

J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
21
1
characteristic signals at l 5.36 ppm (dd, J1,2 0.8, J2,3 2.9
(dd, J3,4=J4,5=10.0) for H-4, respectively, in its H
NMR spectrum. With the tetrasaccharide donor 22 or
29 and the monosaccharide acceptor 6 in hand, the
pentasaccharide 23 or 30 was readily obtained by cou-
pling of the donor and acceptor in dichloromethane in
the presence of TMSOTf.
Hz) for H-2 in its 1H NMR spectrum. Coupling of
2,3,4-tri-O-benzoyl-b-
L
-xylopyranosyl trichloroacetimi-
date (12) with 2,3-O-isopropylidene-a-
L-rhamnopyran-
oside (2) in the presence of a catalytic amount of
TMSOTf gave (1“4)-linked disaccharide 13 in high
yield, which could be used in the next step without
purification. O-Deisopropylidenation of 13 in 90% trifl-
uoroacetic acid (TFA) at room temperature furnished
the diol 14 in 82.7% overall yield. In the same way,
compound 16 could be obtained by condensation of 3
and 12, its 3,4-O-deisopropylidenation gave the (1“2)-
linked disaccharide acceptor 17 in satisfactory yield
(83.2% for two steps). Both structures of 14 and 17
were confirmed by acetylation to give allyl 2,3,4-tri-O-
Hydrazinolysis to remove the phthalimido group
from 23 or 30 was carried out in 10% hydrazine hy-
drate–EtOH under reflux, and it was accompanied by
reduction of the allyl group and debenzoylation. Subse-
quent acetylation of the resultant product with acetic
anhydride in pyridine readily gave acetylated pentasac-
charide 24 or 31. Their 1H NMR spectra showed a
characteristic signal at l 5.56 ppm (J 6.4 Hz), or 5.55
ppm (J 6.6 Hz) as a broad doublet for AcNH. Finally
deacylation of 24 or 31 in ammonia-saturated methanol
gave the target pentasaccharide 25 or 32. Their
bioassays are in progress and will be reported in due
course.
benzoyl-b-
L
-xylopyranosyl-(1“4)-2,3-O-acetyl-a-L-
rhamnopyranoside (15), showing characteristic signals
at l 3.67 ppm (dd, J3,4=J4,5=9.6 Hz) for H-4, and
allyl 2,3,4-tri-O-benzoyl-b-
L
-xylopyranosyl-(1“2)-3,4-
O-acetyl-a-
L
-rhamnopyranoside (18), showing charac-
In summary, branched pentasaccharides, containing
D-GlcpNAc, L-xylose and rhamnose, were synthesized
in a highly regioselective way with a simple procedure.
Large-scale preparations can be performed with this
method.
teristic signals at l 4.08 ppm (dd, J1,2 1.6, J2,3 3.4) for
1
H-2, respectively, in their H NMR spectra.
As we expected, condensation of the diol acceptor 14
with the disaccharide donor 11 at −20 °C selectively
gave 2-O-glycosylated tetrasaccharide 19 (81.9%) in
dichloromethane in the presence of TMSOTf. Acetyla-
tion of compound 19 with acetic anhydride in pyridine,
followed by deallylation with PdCl2 and trichloroace-
timidation with CCl3CN in the presence of DBU or
K2CO3, gave the tetrasaccharide donor 22 (70.4% from
3. Experimental
3.1. General methods
1
19). The H NMR spectrum of 22 gave H-3I (5.33 ppm,
J2,3 3.2, J3,4 9.7 Hz) as a downfield doublet of doublets,
and H-3II as an upfield signal, (4.27 ppm, J2,3 3.4, J3,4
9.8 Hz), confirming the structure of 19. Similarly, cou-
pling of the diol acceptor 17 with 11 selectively gave
4-O-glycosylated tetrasaccharide 26 (88.8%). The selec-
tivity was confirmed by acetylation of 26, then deallyla-
tion and trichloroacetimidation, giving the tetra-
Melting points were determined with a ‘Mel-Temp’
apparatus. Optical rotations were determined with a
Perkin–Elmer model 241-MC automatic polarimeter
1
for solutions in a 1-dm, jacketed cell. H NMR and 13C
NMR spectra were recorded with Varian XL-400 and
Varian XL-200 spectrometers for solutions in CDCl3 or
in D2O as indicated. Chemical shifts are expressed in
ppm downfield from the Me4Si absorption. Mass spec-
tra were recorded with a VG PLATFORM mass spec-
1
saccharide donor 29 (66.8% from 26). H NMR spec-
trum of 29 showed two characteristic rhamnose H-3
signals at l 5.02 (dd, J2,3 3.1, J3,4 9.8 Hz, H-3I) and 4.35
(dd, J2,3 3.2, J3,4 9.7 Hz, H-3II), respectively. These
stereoselective results further revealed that steric factor
of the acceptor plays an important role in their glycosy-
lation reactions.
trometer
using
the
ESI
mode.
Thin-layer
chromatography (TLC) was performed on silica gel HF
with detection by charring with 30% (v/v) sulfuric acid
in MeOH or by UV detection. Column chromatogra-
phy was conducted by elution of a column (8×100,
16×240, 18×300, 35×400 mm) of silica gel (100–200
mesh) and EtOAc–petroleum ether (bp 60–90 °C) as
the eluent. Analytical LC was performed with a Gilson
HPLC consisting of a pump (model 306), stainless steel
column packed with silica gel (Spherisorb SiO2, 10×
300 mm or 4.6×250 mm), differential refractometer
(132-RI Detector), UV–Vis detector (model 118).
EtOAc–petroleum ether (bp 60–90 °C) was used as the
eluent at a flow rate of 1–4 mL/min. Solutions were
concentrated at a temperature B60 °C under dimin-
ished pressure.
Treatment of allyl a- -rhamnopyranoside (1) with 1.1
L
equiv of acetyl chloride and 10.0 equiv of pyridine in
dry dichloromethane selectively gave allyl 3-O-acetyl-a-
L-rhamnopyranoside. Without working up, the mixture
was benzoylated with benzoyl chloride to give allyl
-rhamnopyranoside (5)
3-O-acetyl-2,4-di-O-benzoyl-a-
L
in a total yield of 79.3%. Structure of 5 was confirmed
by selective deacetylation15 to give allyl 2,4-di-O-ben-
zoyl-a- -rhamnopyranoside (6), showing characteristic
L
signals at l 4.34 ppm (dd, J2,3 3.5, J3,4 10.0) for H-3, l
5.41 ppm (dd, J1,2 1.7, J2,3 3.5) for H-2, and 5.28 ppm

22
J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
3.2. Preparation of allyl 3,4-O-isopropylidene-a-
rhamnopyranoside (3)
L
-
mL, 11 mmol) in anhyd CH2Cl2 (10 mL) was added
dropwise to the solution within 30 min at 0 °C. The
reaction mixture was slowly raised to rt and stirred for
2 h, at the end of which time TLC (1:2 petroleum
ether–EtOAc) indicated that the reaction was complete.
Benzoyl chloride (3.0 mL, 25 mmol) was added to the
reaction mixture, and stirring was continued until TLC
(4:1 petroleum ether–EtOAc) indicated that the reac-
tion was complete. The reaction mixture was diluted
with CH2Cl2 (100 mL), washed with water, 1 N HCl,
and dried (Na2SO4). The solution was concentrated,
and purification of the residue by flash column chro-
matography on a silica gel column (4:1 petroleum
ether–EtOAc) gave compound 5 (3.60 g, 79.3%) as a
syrup. [h]D +76.3° (c 1.1, CHCl3); 1H NMR (400
MHz, CDCl3): l 8.13–7.26 (m, 10 H, 2 BzꢁH), 5.98 (m,
1 H, OCH2CHꢀCH2), 5.65 (dd, 1 H, J2,3 3.4, J3,4 10.1
Hz, H-3), 5.54 (dd, 1 H, J1,2 1.7, J2,3 3.4 Hz, H-2), 5.47
(dd, 1 H, J3,4=J4,5=10.1 Hz, H-4), 5.39–5.25 (m, 2 H,
OCH2CHꢀCH2), 4.98 (d, 1 H, J1,2 1.7, H-1), 4.21–4.06
(m, 3 H, H-5, OCH2CHꢀCH2), 1.86 (s, 3 H, COCH3),
1.32 (d, 3 H, J5,6 6.2 Hz, H-6). Anal. Calcd for
C25H26O8: C, 66.07; H, 5.77. Found: C, 66.28; H, 5.50.
To a solution of allyl a- -rhamnoside (1) (2.04 g, 10
L
mmol) in anhyd DMF (25 mL) was added p-toluenesul-
fonic acid monohydrate (19 mg, 0.1 mmol) and 2-
methoxypropene (1.5 mL, 15 mmol) under N2
protection. The mixture was stirred at room tempera-
ture (rt) for 2 h, and TLC (3:1 petroleum ether–EtOAc)
indicated that the reaction was complete. Sodium bicar-
bonate (2.52 g, 30 mmol) was added to the reaction
mixture, and the mixture was stirred for additional 1 h.
After filtration, the mixture was concentrated in vacuo
to give a residue, which was subjected to silica gel
column chromatography (3:1 petroleum ether–EtOAc)
to give 2 (0.74 g, 30.3%) and 3 (1.52 g, 62.3%) as
colorless oils. For 2: [h]D −33.5° (c 1.1, CHCl3); lit.16
[h]D −36.6° (c 1.0, CHCl3). For 3: [h]D −43.3° (c 1.1,
1
CHCl3); H NMR (400 MHz, CDCl3): l 5.89 (m, 1 H,
OCH2CHꢀCH2), 5.33–5.19 (m, 2 H, OCH2CHꢀCH2),
4.83 (d, 1 H, J1,2 1.4, H-1), 4.19–4.00 (m, 2 H,
OCH2CHꢀCH2), 3.96 (dd, 1 H, J1,2 1.4, J2,3 3.4 Hz,
H-2), 3.78 (dd, 1 H, J2,3 3.4, J3,4 9.6 Hz, H-3), 3.71 (m,
1 H, H-5), 3.41 (dd, 1 H, J3,4=J4,5=9.6 Hz, H-4), 1.45
(s, 3 H, C(CH3)2), 1.35 (s, 3 H, C(CH3)2), 1.31 (d, 3 H,
J5,6 6.3 Hz, H-6). Anal. Calcd for C12H20O5: C, 59.00;
H, 8.26. Found: C, 58.89; H, 8.02.
3.5. Allyl 2,4-di-O-benzoyl-a-L-rhamnopyranoside (6)
To a solution of 5 (2.27 g, 5 mmol) in anhyd MeOH (50
mL) was added AcCl (1.5 mL) at 0 °C. The solution
was stoppered in a flask and stirred at rt until TLC (3:1
petroleum ether–EtOAc) showed that the starting ma-
terial disappeared. The solution was neutralized with
Et3N, then concentrated to dryness. The residue was
passed through a short silica gel column to give 6 (1.81
3.3. Allyl 2-O-acetyl-3,4-O-isopropylidene-a-L-
rhamnopyranoside (4)
To a solution of 3 (73 mg, 0.3 mmol) in Py (5 mL) was
added Ac2O (2.0 mL, 2 mmol). The reaction mixture
was stirred at rt for 12 h, at the end of which time TLC
(4:1 petroleum ether–EtOAc) indicated that the reac-
tion was complete. The reaction mixture was concen-
trated, and then the residue was purified by flash
column chromatography on a silica gel column (4:1
petroleum ether–EtOAc) to give compound 4 (70 mg,
82.4%) as a syrup: [h]D −30.3° (c 1.1, CHCl3); 1H
1
g, 87.9%) as a syrup: [h]D +46.7° (c 1.1, CHCl3); H
NMR (400 MHz, CDCl3): l 8.12–7.45 (m, 10 H, 2
BzꢁH), 5.97 (m, 1 H, OCH2CHꢀCH2), 5.41 (dd, 1 H,
J1,2 1.7, J2,3 3.5 Hz, H-2), 5.39–5.25 (m, 2 H,
OCH2CHꢀCH2), 5.28 (dd, 1 H, J3,4=J4,5=10.0 Hz,
H-4), 5.02 (d, 1 H, J1,2 1.7, H-1), 4.34 (dd, 1 H, J2,3 3.5,
J3,4 10.0 Hz, H-3), 4.27–4.05 (m,
3 H, H-5,
NMR (400 MHz, CDCl3):
l
5.89 (m,
1
H,
OCH2CHꢀCH2), 1.33 (d, 3 H, J5,6 6.3 Hz, H-6). Anal.
Calcd for C23H24O7: C, 66.98; H, 5.87. Found: C, 66.73;
H, 5.52.
OCH2CHꢀCH2), 5.36 (dd, 1 H, J1,2 0.8, J2,3 2.9 Hz,
H-2), 5.33–5.20 (m, 2 H, OCH2CHꢀCH2), 4.86 (d, 1 H,
J1,2 0.8, H-1), 4.21–3.98 (m, 2 H, OCH2CHꢀCH2), 3.93
(m, 1 H, H-5), 3.88 (dd, 1 H, J2,3 2.9, J3,4 9.5 Hz, H-3),
3.52 (dd, 1 H, J3,4=J4,5=9.5 Hz, H-4), 2.12 (s, 3 H,
COCH3), 1.44 (s, 3 H, C(CH3)2), 1.42 (s, 3 H, C(CH3)2),
1.35 (d, 3 H, J5,6 6.2 Hz, H-6). Anal. Calcd for
C14H22O6: C, 58.73; H, 7.75. Found: C, 58.93; H, 7.50.
3.6. Allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-D-
glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a-L-rhamno-
pyranoside (9)
3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-b-
ranosyl trichloroacetimidate (7) (5.80 g, 10 mmol) and
allyl a- -rhamnopyranoside (2) (2.04 mg, 10 mmol)
D-glucopy-
3.4. Allyl 3-O-acetyl-2,4-di-O-benzoyl-a-
ranoside (5)
L-rhamnopy-
L
were dried together under high vacuum for 2 h, then
dissolved in anhyd CH2Cl2 (40 mL). TMSOTf (60 mL,
0.2 equiv) was added dropwise at −25 °C with N2
protection. The reaction mixture was stirred for 3 h,
during which time the temperature was gradually raised
Allyl a- -rhamnopyranoside (1) (2.04 g, 10 mmol) was
L
dissolved in dry CH2Cl2 (40 mL) containing Py (8.1
mL, 100 mmol), then under N2 protection, AcCl (0.8

J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
23
to ambient temperature. Then the mixture was neutral-
ized with Et3N, and concentrated to dryness under
reduced pressure to afford the crude allyl 3,4,6-tri-O-
on a silica gel column with 2:1 petroleum ether–EtOAc
as the eluent, furnished the disaccharide donor 11 (3.90
g, 88.8%) as a syrup: [h]D +38.4° (c 0.5, CHCl3); H
1
acetyl-2-deoxy-2-phthalimido-b-
D
-glucopyranosyl-(1
NMR (400 MHz, CDCl3): l 8.80 (s, 1 H, CNHCCl3),
8.12–7.22 (m, 14 H, Ph), 6.42 (d, 1 H, J1,2 1.9 Hz, H-1),
5.69 (dd, 1 H, J1,2 1.9, J2,3 3.5 Hz, H-2), 6.63 (dd, 1 H,
J2%,3% 10.7, J3%,4% 10.0 Hz, H-3%), 5.58 (d, 1 H, J1%,2% 8.3 Hz,
H-1%), 5.44 (dd, 1 H, J3,4=J4,5=9.8 Hz, H-4), 5.04 (dd,
1 H, J3%,4%=J4%,5%=10.0 Hz, H-4%), 4.38 (dd, 1 H, J2,3 3.5,
J3,4 9.8 Hz, H-3), 4.22 (dd, 1 H, J1%,2% 8.3, J2%,3% 10.7 Hz,
H-2%), 4.11–3.83 (m, 4 H), 1.96 (s, 3 H, COCH3), 1.71
(s, 3 H, COCH3), 1.58 (s, 3 H, COCH3), 1.15 (d, 3 H,
J5,6 6.3 Hz, H-6). Anal. Calcd for C42H39Cl3N2O16: C,
54.00; H, 4.21. Found: C, 53.81; H, 4.38.
“3)-a- -rhamnopyranoside (8). To a solution of crude
L
8 in Py (20 mL), benzoyl chloride (3.5 mL, 30 mmol)
was added dropwise, and the mixture was stirred
overnight at rt. TLC (3:1 petroleum ether–EtOAc)
indicated that the reaction was complete. Ice water was
added, and the mixture was diluted with CH2Cl2,
washed with 1 N HCl, water, and satd aq NaHCO3.
The organic layer was combined, dried, and concen-
trated. Purification of the crude product by column
chromatography (3:1 petroleum ether–EtOAc) gave 9
(4.93 g, 59.5% for two steps) as a syrup: [h]D +40.8° (c
1
0.5, CHCl3); H NMR (400 MHz, CDCl3): l 8.10–7.18
3.8. Allyl 2,3,4-tri-O-benzoyl-b-
a- -rhamnopyranoside (14)
L-xylopyranosyl-(1“4)-
(m, 14 H, Ph), 5.97 (m, 1 H, CH2CHꢀCH2), 5.64–5.55
(m, 2 H, H-3%, H-4%), 5.51 (dd, 1 H, J1,2 1.8, J2,3 3.7 Hz,
H-2), 5.38–5.25 (m, 2 H, OCH2CHꢀCH2), 5.28 (dd, 1
H, J3,4=J4,5=9.7 Hz, H-4), 5.03 (d, 1 H, J1%,2% 9.1 Hz,
H-1%), 4.99 (d, 1 H, J1,2 1.8 Hz, H-1), 4.31 (dd, 1 H, J2,3
L
2,3,4-Tri-O-benzoyl-a-
idate (12) (6.07 g, 10.0 mmol) and allyl 2,3-O-isopropyl-
idene-a- -rhamnopyranoside (2) (2.44 g, 10.0 mmol)
L-xylopyranosyl trichloroacetim-
L
3.7, J3,4 9.8, H-3), 4.24–4.17 (m,
2
H, H-2%,
were dried together under high vacuum for 2 h, then
dissolved in anhyd CH2Cl2 (50 mL). TMSOTf (18.0 mL,
0.10 mmol) was added dropwise at −0 °C with N2
protection. The reaction mixture was stirred for 2 h,
during which time the temperature was gradually
warmed to ambient temperature. Then the mixture was
neutralized with Et3N and concentrated to dryness
under reduced pressure to afford the crude allyl 2,3,4-
OCH2CHꢀCH2), 4.13–4.11 (m, 2 H), 4.05 (m, 1 H,
OCH2CHꢀCH2), 3.92–3.83 (m, 2 H), 1.95 (s, 3 H,
COCH3), 1.91 (s, 3 H, COCH3), 1.71 (s, 3 H, COCH3),
1.22 (d, 3 H, J5,6 6.3 Hz, H-6); 13C NMR (100 MHz,
CDCl3): l 170.2, 169.5, 168.7, 165.5, 164.4, 98.1, 96.0,
76.0, 72.0, 71.8, 71.1, 70.1, 68.3, 68.2, 65.8, 61.4, 54.1,
20.2, 19.9, 19.7, 17.0. Anal. Calcd for C43H43NO16: C,
62.24; H, 5.22. Found: C, 62.28; H, 5.56.
tri-O-benzoyl-b-
L
-xylopyranosyl-(1“4)-2,3-O-isopro-
pylidene-a- -rhamnopyranoside (13). Compound 13
L
3.7. 3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-b-
glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a-L-rhamno-
pyranosyl trichloroacetimidate (11)
D-
was dissolved in 90% TFA (50 mL) and stirred for 2 h,
at the end of which time the reaction mixture was
poured into toluene (200 mL), and then the mixture
was concentrated. The residue was purified by flash
chromatography (1:1 petroleum ether–EtOAc) to give
14 (5.36 g, 82.7% for two steps) as a syrup: [h]D −9.6°
To a solution of allyl 3,4,6-tri-O-acetyl-2-deoxy-2-ph-
thalimido-b- -glucopyranosyl-(1“3)-2,4-di-O-ben-
zoyl-a- -rhamnopyranoside (9) (4.15 g, 5 mmol) in 90%
D
1
L
(c 1.0, CHCl3); H NMR (400 MHz, CDCl3): l 7.97–
HOAc (50 mL) containing NaOAc (1.46 g, 15 mmol)
was added PdCl2 (270 mg, 2.5 mmol), and the mixture
was stirred for 12 h, at the end of which time TLC (2:1
petroleum ether–EtOAc) indicated that the reaction
was complete. The mixture was diluted with CH2Cl2
(150 mL), washed with water and satd aq NaHCO3.
The organic layer was concentrated, and the residue
was passed through a short silica gel column with 2:1
petroleum ether–EtOAc as the eluent to give crude
7.32 (m, 15 H, 3 Ph), 5.89–5.81 (m, 2 H, H-3%,
OCH2CHꢀCH2), 5.53 (dd, 1 H, J1%,2% 7.5, J2%,3% 9.4 Hz,
H-2%), 5.39 (m, 1 H, H-4%), 5.27–5.15 (m, 2 H,
OCH2CHꢀCH2), 4.81 (d, 1 H, J1,2 0.8 Hz, H-1), 4.79 (d,
1 H, J1%,2% 7.5 Hz, H-1%), 4.50 (dd, 1 H, J 5.3, J 11.6 Hz,
H-5%), 4.08–4.02 (m, 2 H, H-2, OCH2CHꢀCH2), 3.94–
e
3.86 (m, 2 H, H-3, OCH2CHꢀCH2), 3.70–3.61 (m, 2 H,
H-5, H-5%), 3.46 (dd, 1 H, J3,4=J4,5=9.7 Hz, H-4),
a
1.06 (d, 3 H, J5,6 6.4 Hz, H-6). Anal. Calcd for
3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-
D
-glucopy-
C35H36O12: C, 64.81; H, 5.59. Found: C, 64.72; H, 5.38.
ranosyl-(1“3)-2,4-di-O-benzoyl-a,b- -rhamnopyran-
L
ose (10) (3.71 g, 94.0%). Compound 10 was dissolved in
CH2Cl2 (30 mL), and CCl3CN (1.0 mL, 10 mmol) and
DBU (135 mL, 0.9 mmol) were added. The reaction
mixture was stirred for 2 h, at the end of which time
TLC (2:1 petroleum ether–EtOAc) indicated that the
reaction was complete. Concentration of the reaction
mixture, followed by purification of the crude product
3.9. Allyl 2,3,4-tri-O-benzoyl-b-
L-xylopyranosyl-(1“4)-
2,3-di-O-acetyl-a- -rhamnopyranoside (15)
L
To a solution of allyl 2,3,4-tri-O-benzoyl-b-
L-xylopy-
ranosyl-(1“4)-a- -rhamnopyranoside (14) (65 mg, 0.1
L
mmol) in Py (5 mL) was added Ac2O (1.0 mL, 1 mmol).
The reaction mixture was stirred at rt for 12 h, at the

24
J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
3.11. Allyl 2,3,4-tri-O-benzoyl-b-
L-xylopyranosyl-(1“
end of which time TLC (3:1 petroleum ether–EtOAc)
indicated that the reaction was complete. The reaction
mixture was concentrated, and purification of the
residue by flash column chromatography on a silica gel
column (3:1 petroleum ether–EtOAc) gave compound
15 (586 mg, 80.1%) as a syrup: [h]D +10.3° (c 1.4,
2)-3,4-di-O-acetyl-a- -rhamnopyranoside (18)
L
To a solution of allyl 2,3,4-tri-O-benzoyl-b-
L-xylopy-
ranosyl-(1“2)-a- -rhamnopyranoside (17) (65 mg, 0.1
L
mmol) in Py (5 mL) was added Ac2O (1.0 mL, 1 mmol).
The reaction mixture was stirred at rt for 12 h, at the
end of which time TLC (3:1 petroleum ether–EtOAc)
indicated that the reaction was complete. The reaction
mixture was concentrated, and purification of the
residue by flash column chromatography on a silica gel
column (3:1 petroleum ether–EtOAc) gave compound
18 (61 mg, 83.3%) as a syrup: [h]D +8.4° (c 1.1,
1
CHCl3); H NMR (400 MHz, CDCl3): l 8.05–7.32 (m,
15 H, 3 Ph), 5.83 (m, 1 H, CH2CHꢀCH2), 5.72 (dd, 1
H, J2%,3%=J3%,4%=6.4 Hz, H-3%), 5.38 (dd, 1 H, J2,3 3.6,
J3,4 9.6 Hz, H-3), 5.32–5.17 (m, 5 H, H-2, H-2%, H-4%,
OCH2CHꢀCH2), 4.95 (d, 1 H, J1%,2% 4.6 Hz, H-1%), 4.71
(d, 1 H, J1,2 1.6 Hz, H-1), 4.44 (dd, 1 H, J 3.8, J 12.4
Hz, H-5%), 4.09 (m, 1 H, OCH2CHꢀCH2), 3.93 (m, 1 H,
e
1
CHCl3); H NMR (400 MHz, CDCl3): l 8.05–7.24 (m,
OCH2CHꢀCH2), 3.77–3.71 (m, 2 H, H-5, H-5%), 3.67
a
15 H, 3 Ph), 5.77 (m, 1 H, CH2CHꢀCH2), 5.58 (dd, 1
H, J2%,3%=J3%,4%=6.7 Hz, H-3%), 5.28 (dd, 1 H, J2,3 3.4,
J3,4 9.9 Hz, H-3), 5.32–5.17 (m, 4 H, H-2%, H-4%,
OCH2CHꢀCH2), 5.07 (dd, 1 H, J3,4=J4,5=9.9 Hz,
H-4), 4.85 (d, 1 H, J1%,2% 4.6 Hz, H-1%), 4.73 (d, 1 H, J1,2
1.6 Hz, H-1), 4.55 (dd, 1 H, J 3.0, J 12.6 Hz, H-5%), 4.08
(dd, 1 H, J1,2 1.6, J2,3 3.4, H-2), 4.03 (m, 1 H,
OCH2CHꢀCH2), 3.86 (m, 1 H, OCH2CHꢀCH2), 3.73–
3.67 (m, 2 H, H-5, H-5%), 2.15 (s, 3 H, COCH3), 2.06 (s,
3 H, COCH3), 1.22 (d, 3 H, J5,6 6.1 Hz, H-6). Anal.
Calcd for C34H40O14: C, 63.93; H, 5.50. Found: C,
64.00; H, 5.35.
(dd, 1 H, J3,4=J4,5=9.6 Hz, H-4), 2.13 (s, 3 H,
COCH3), 2.06 (s, 3 H, COCH3), 1.23 (d, 3 H, J5,6 6.0
Hz, H-6). Anal. Calcd for C39H40O14: C, 63.93; H, 5.50.
Found: C, 63.42; H, 5.38.
3.10. Allyl 2,3,4-tri-O-benzoyl-b-
2)-a- -rhamnopyranoside (17)
L-xylopyranosyl-(1“
L
2,3,4-Tri-O-benzoyl-a-
idate (12) (6.06 g, 10.0 mmol) and allyl 3,4-O-isopropyl-
idene-a- -rhamnopyranoside (3) (2.44 g, 10.0 mmol)
L-xylopyranosyl trichloroacetim-
L
were dried together under high vacuum for 2 h, then
dissolved in anhyd CH2Cl2 (50 mL). TMSOTf (18 mL,
0.1 mmol) was added dropwise at 0 °C with N2 protec-
tion. The reaction mixture was stirred for 2 h, during
which time the temperature was gradually warmed to
ambient temperature. Then the mixture was neutralized
with Et3N and concentrated to dryness under reduced
pressure to afford the crude allyl 2,3,4-tri-O-benzoyl-b-
3.12. Allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-
D
-glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a-
rhamnopyranosy-(1“2)-[2,3,4-tri-O-benzoyl-b-
xylopyranosyl-(1“4)]-a- -rhamnopyranoside (19)
L-
L-
L
3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-b-
ranosyl-(1“3)-2,4-di-O-benzoyl-a- -rhamnopyranosyl
trichloroacetimidate (11) (4.7 g, 5 mmol) and allyl
2,3,4-tri-O-benzoyl-b- -xylopyranosyl-(1“4)-a-L-
D-glucopy-
L
L
L
- xylopyranosyl - (1“2) - 3,4 - O - isopropylidene - a - L-
rhamnopyranoside (14) (3.3 g, 5 mmol) were dried
together under high vacuum for 2 h, then dissolved in
anhyd CH2Cl2 (40 mL). TMSOTf (36 mL, 0.2 mmol)
was added dropwise at −25 °C with N2 protection.
The reaction mixture was stirred for 3 h, during which
time the temperature was gradually raised to ambient
temperature. Then the mixture was neutralized with
Et3N, and concentrated. Purification of the crude
product by column chromatography (2:1 petroleum
ether–EtOAc) gave 19 (5.81 g, 81.9%) as a syrup: [h]D
rhamnopyranoside (16). Compound 16 was dissolved in
90% TFA (50 mL) and the mixture was stirred for 2 h,
at the end of which time the reaction mixture was
poured into toluene (200 mL), and then the mixture
was concentrated. The residue was purified by flash
chromatography (1:1 petroleum ether–EtOAc) to give
17 (5.39 g, 83.2% for two steps) as a syrup. [h]D +6.0°
1
(c 1.0, CHCl3); H NMR (400 MHz, CDCl3): l 7.97–
7.33 (m, 15 H, 3 Ph), 5.84–5.75 (m, 2 H, H-3%,
OCH2CHꢀCH2), 5.44 (dd, 1 H, J1%,2% 6.6, J2%,3% 8.4 Hz,
H-2%), 5.36 (m, 1 H, H-4%), 5.21–5.10 (m, 2 H,
OCH2CHꢀCH2), 4.84 (d, 1 H, J1%,2% 6.6 Hz, H-1%), 4.66
(d, 1 H, J1,2 1.0 Hz, H-1), 4.50 (dd, 1 H, J 4.8, J 11.8
1
+3.9° (c 1.0, CHCl3); H NMR (400 MHz, CDCl3): l
8.12–7.22 (m, 29 H, 5 Ph, Phth), 5.86 (m, 1 H,
OCH2CHꢀCH2), 5.84 (dd, 1 H, J3,4=J4,5=9.7 Hz,
H-4II), 5.76 (dd, 1 H, J1,2 1.0, J2,3 2.7 Hz, H-2II), 5.70
(dd, 1 H, J2,3=J3,4=9.3 Hz, H-3IV), 5.51–5.47 (m, 2
H, H-1III, H-2IV), 5.38–5.32 (m, 2 H, H-3III, H-4IV),
5.25 (m, 1 H, OCH2CHꢀCH2), 5.18 (d, 1 H, J1,2 1.8 Hz,
H-1II), 5.16 (m, 1 H, OCH2CHꢀCH2), 5.12 (dd, 1 H,
Hz, H-5%), 4.05 (m, 1 H, OCH2CHꢀCH2), 4.00 (dd, 1 H,
e
J1,2 1.0, J2,3 3.1, H-2), 3.82–3.66 (m, 3 H, H-3, H-5%,
OCH2CHꢀCH2), 3.54 (m, 1 H, H-5), 3.34 (dd, 1 H,
J3,4=J4,5=9.7 Hz, H-4), 2.62 (bs, 2 H, 2 OH), 1.06 (d,
3,4=J4,5=9.7 Hz, H-4III), 4.84 (d, 1 H, J1,2 7.8 Hz,
3 H, J5,6 6.4 Hz, H-6). Anal. Calcd for C35H36O12: C,
64.81; H, 5.59. Found: C, 64.67; H, 5.50.
J
H-1IV), 4.76 (d, 1 H, J1,2 0.8 Hz, H-1I), 4.32–4.21 (m, 4

J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
25
H), 5.10–5.06 (m, 2 H), 3.96–3.80 (m, 6 H), 3.63–3.56
(m, 2 H), 2.07 (s, 3 H, COCH3), 1.99 (s, 3 H, COCH3),
1.79 (s, 3 H, COCH3), 1.37 (d, 3 H, J5,6 6.2 Hz, H-6),
1.03 (d, 3 H, J5,6 6.3 Hz, H-6); 13C NMR (100 MHz,
CDCl3): l 170.5, 169.9, 169.4, 167.1, 165.7, 165.4,
165.1, 164.9, 164.8, 164.7, 117.3, 102.2, 99.5, 97.8, 97.6,
84.8, 72.4, 72.1, 71.3, 71.1, 70.3, 69.9, 69.4, 69.0, 67.8,
67.6, 66.7, 62.7, 62.0, 54.7, 20.6, 20.5, 20.3, 18.1, 16.8.
Anal. Calcd for C75H73NO27: C, 63.42; H, 5.18. Found:
C, 63.28; H, 5.36.
COCH3), 2.02 (s, 3 H, COCH3), 2.00 (s, 3 H, COCH3),
1.78 (s, 3 H, COCH3), 1.41 (d, 3 H, J5,6 6.3 Hz, H-6),
1.21 (d, 3 H, J5,6 6.3 Hz, H-6). Anal. Calcd for
C76H71Cl3N2O28: C, 58.26; H, 4.57. Found: C, 58.40; H,
4.38.
3.14. Allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-
D
-glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a-
rhamnopyranosyl-(1“2)-[2,3,4-tri-O-benzoyl-b-
xylopyranosyl-(1“4)-]3-O-acetyl-a- -rhamnopyranosyl-
(1“3)-2,4-di-O-benzoyl-a- -rhamnopyranoside (23)
L-
L-
L
L
3.13. 3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-b-
glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a- -rhamno-
pyranosyl-(1“2)-[2,3,4-tri-O-benzoyl-b- -xylopyran-
-rhamnopyranosyl
D-
L
Compound 22 (1.57 g, 1.0 mmol) and allyl 3,4-di-O-
benzoyl-a- -rhamnopyranoside (6) (0.42 g, 1.0 mmol)
L
L
osyl-(1“4)-]3-O-acetyl-a-
L
were dried together under high vacuum for 2 h, then
dissolved in anhyd CH2Cl2 (10 mL). TMSOTf (9.0 mL,
0.05 mmol) was added dropwise at 0 °C with N2 protec-
tion. The reaction mixture was stirred for 3 h, during
which time the temperature was gradually raised to
ambient temperature. Then the mixture was neutralized
with Et3N, concentrated to dryness. Purification of the
residue by column chromatography (1:1 petroleum
ether–EtOAc) gave 23 (1.30 g, 71.4%) as a foamy solid:
[h]D +62.0° (c 1.2, CHCl3); 1H NMR (400 MHz,
CDCl3): 8.13–7.30 (m, 39 H, 7 Ph, Phth), 5.97 (m, 1 H,
CH2CHꢀCH2), 5.43 (d, 1 H, J1,2 8.3 Hz, H-1), 4.98 (d,
1 H, J1,2 1.5 Hz, H-1), 4.92 (d, 1 H, J1,2 1.6 Hz, H-1),
4.80 (d, 1 H, J1,2 5.8 Hz, H-1), 4.53 (d, 1 H, J1,2 2.0 Hz,
H-1), 2.12 (s, 3 H, COCH3), 2.00 (s, 3 H, COCH3), 1.79
(s, 6 H, 2 COCH3), 1.30 (d, 3 H, J5,6 6.2 Hz, H-6), 1.07
(d, 3 H, J5,6 6.3 Hz, H-6), 1.04 (d, 3 H, J5,6 6.4 Hz,
H-6); 13C NMR (100 MHz, CDCl3): l 170.0, 169.4,
169.0, 168.8, 166.8, 165.5, 165.1, 165.0, 164.9, 164.5,
164.3, 164.2, 133.5, 133.1, 132.9, 132.8, 132.7, 132.6,
130.6, 130.0, 129.4, 129.3, 129.2, 129.0, 128.9, 128.7,
128.1, 128.0, 127.9, 127.8, 127.6, 117.3, 100.3, 100.0,
98.6, 97.3, 96.2, 20.3, 20.2, 20.1, 19.9, 17.5, 17.2, 16.8.
Anal. Calcd for C97H93NO34: C, 64.13; H, 5.16. Found:
C, 63.91; H, 5.28.
trichloroacetimidate (22)
To a solution of compound 19 (2.84 g, 2 mmol) in Py
(25 mL) was added Ac2O (10 mL, 10 mmol). The
reaction mixture was stirred at rt for 12 h and concen-
trated to give the crude product 20 as a syrup, which
was directly used in the next step without separation.
To the solution of 20 in 90% HOAc (20 mL) containing
NaOAc (60 mg, 6 mmol) was added PdCl2 (180 mg, 1.0
mmol), and the mixture was stirred for 12 h, at the end
of which time TLC (1:1 petroleum ether–EtOAc) indi-
cated that the reaction was complete. The mixture was
diluted with CH2Cl2 (100 mL), washed with water and
satd aq NaHCO3. The organic layer was concentrated,
and the residue was passed through a short silica gel
column with 1:1 petroleum ether–EtOAc as the eluent
to give crude 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-
b -
rhamnopyranosyl - (1“2) - [2,3,4 - tri - O - benzoyl - b -
xylopyranosyl-(1“4)-]3-O-acetyl-a,b-
D
- glucopyranosyl - (1“3) - 2,4 - di - O - benzoyl - a -
L
-
-
L
L-rhamnopyran-
ose (21) (2.49 g, 87.7% for two steps). Compound 21
was dissolved in CH2Cl2 (20 mL), and CCl3CN (0.5
mL, 5 mmol) and DBU (50 mL, 0.33 mmol) were
added. The reaction mixture was stirred for 2 h, at the
end of which time TLC (2:1 petroleum ether–EtOAc)
indicated that the reaction was complete. Concentra-
tion of the reaction mixture, followed by purification of
the crude product on a silica gel column with 2:1
petroleum ether–EtOAc as the eluent, furnished the
tetrasaccharide donor 22 (2.20 g, 80.3%) as a syrup:
[h]D +25.6° (c 1.0, CHCl3); 1H NMR (400 MHz,
CDCl3): l 8.63 (s, 1 H, CNHCCl3), 7.97–7.33 (m, 29
H, 5 Ph, Phth), 6.19 (d, 1 H, J1,2 2.1 Hz, H-1I),
5.75–5.56 (m, 2 H, H-3IV, H-4II), 5.55 (dd, 1 H, J1,2 2.0,
J2,3 3.4 Hz, H-2II), 5.53 (d, 1 H, J1,2 8.3 Hz, H-1III),
5.38–5.34 (m, 2 H, H-2IV, H-3III), 5.33 (dd, 1 H, J2,3
3.2, J3,4 9.7 Hz, H-3I), 5.30 (m, 1 H, H-4IV), 5.16 (dd, 1
H, J3,4=J4,5=9.5 Hz, H-4III), 4.97 (d, 1 H, J1,2 2.0 Hz,
H-1II), 4.92 (d, 1 H, J1,2 5.8 Hz, H-1IV), 4.27 (dd, 1 H,
J2,3 3.4, J3,4 9.8 Hz, H-3II), 4.26–4.22 (m, 5 H), 4.00–
3.92 (m, 4 H), 3.65–3.62 (m, 2 H), 2.09 (s, 3 H,
3.15. Propyl 3,4,6-tri-O-acetyl-2-acetamido-2-deoxy-b-
glucopyranosyl-(1“3)-2,4-di-O-acetyl-a- -rhamno-
pyranosyl-(1“2)-[2,3,4-tri-O-acetytyl-b- -xylopyran-
osyl-(1“4)-]3-O-acetyl-a- -rhamnopyranosyl-(1“3)-
2,4-di-O-acetyl-a- -rhamnopyranoside (24)
D-
L
L
L
L
Pentasaccharide 23 (910 mg, 0.5 mmol) was dissolved in
EtOH (36 mL) to which was added 100% hydrazine
hydrate (4 mL), and the solution was refluxed for 48 h.
The solution was then concentrated, and the residue
was co-evaporated several times with toluene. The
residue was taken up in Py (20 mL) to which was added
Ac2O (10 mL). The solution was left to stand for 12 h
at rt and then evaporated to dryness. Purification of the
residue by column chromatography (EtOAc) gave 24
(510 mg, 78.7% for two steps) as a foamy solid: [h]D

26
J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
1
−21.3° (c 1.1, CHCl3); H NMR (400 MHz, CDCl3):
5.56 (bd, 1 H, J 6.4 Hz, NHCOCH3), 5.09 (d, 1 H, J1,2
8.0 Hz, H-1), 4.80 (d, 1 H, J1,2 1.8 Hz, H-1), 4.72 (d, 1
H, J1,2 1.8 Hz, H-1), 4.70 (d, 1 H, J1,2 1.6 Hz, H-1), 4.53
(d, 1 H, J1,2 7.1 Hz, H-1), 2.15, 2.13, 2.10, 2.09, 2.08,
2.07, 2.04, 2.03, 2.02, 2.02, 2.00, 1.91 (12 s, 36 H, 12
COCH3), 1.62 (m, 2 H, OCH2CH2CH3), 1.26 (d, 3 H,
J5,6 6.4 Hz, H-6), 1.24 (d, 3 H, J5,6 6.3 Hz, H-6), 1.18
(d, 3 H, J5,6 6.4 Hz, H-6), 0.94 (t, 3 H, J 7.4 Hz,
OCH2CH2CH3); 13C NMR (100 MHz, CDCl3): l 170.6,
170.4, 170.4, 170.3, 170.2, 170.1, 169.8, 169.7, 167.7,
169.6, 169.5, 169.1, 101.4, 100.3, 99.0, 98.9, 97.18. Anal.
Calcd for C56H81NO33: C, 51.89; H, 6.30. Found: C,
51.81; H, 6.48.
OCH2CHꢀCH2), 3.57–3.47 (m, 2 H), 3.31 (dd, 1 H,
3,4=J4,5=9.7 Hz, H-4I), 2.03 (s, 3 H, COCH3), 1.92
J
(s, 3 H, COCH3), 1.71 (s, 3 H, COCH3), 1.34 (d, 3 H,
J5,6 6.2 Hz, H-6), 1.04 (d, 3 H, J5,6 6.3 Hz, H-6); 13C
NMR (100 MHz, CDCl3): l 170.1, 169.5, 166.8, 165.1,
165.0, 164.8, 164.6, 164.5, 117.2, 100.2, 98.1, 97.4, 95.9,
80.2, 79.7, 71.5, 70.7, 70.5, 70.4, 70.3, 70.0, 69.9, 68.7,
68.6, 67.3, 66.1, 61.7, 61.6, 54.4, 20.2, 20.1, 19.9, 17.6,
17.5. Anal. Calcd for C75H73NO27: C, 63.42; H, 5.18.
Found: C, 63.35; H, 5.51.
3.18. 3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-b-
glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a- -rhamno-
pyranosyl-(1“4)-[2,3,4-tri-O-benzoyl-b- -xylopyran-
-rhamnopyranosyl
D-
L
L
osyl-(1“2)]-3-O-acetyl-a-
L
3.16. Propyl 2-acetamido-2-deoxy-b-
D
-glucopyranosyl-
-xylopyran-
-rhamnopyranosyl-(1“3)-a- -rhamno-
trichloroacetimidate (29)
(1“3)-a- -rhamnopyranosyl-(1“2)-[b-
L
L
osyl-(1“4)-]-a-
L
L
A solution of 26 (2.84 g, 2 mmol) was acetylated with
Ac2O (8 mL) in Py (25 mL) to give 27, which was
deallylated and then trichloroacetimidated under the
same conditions as those used for the preparation of 22,
giving 29 as a foamy solid (2.09 g, 66.8% for three
steps): [h]D +46.1° (c 1.0, CHCl3); 1H NMR (400
MHz, CDCl3): l 8.55 (s, 1 H, CNHCCl3), 7.95–7.33
(m, 29 H, 5 Ph, Phth), 6.10 (d, 1 H, J1,2 1.8 Hz, H-1I),
5.77–5.70 (m, 2 H, H-3III, H-3IV), 5.46 (d, 1 H, J1,2 8.3
Hz, H-1III), 5.41–5.38 (m, 2 H, H-2II, H-2IV), 5.29–5.26
(m, 2 H, H-4III, H-4IV), 5.15 (dd, 1 H, J3,4=J4,5=9.7
Hz, H-4II), 5.07 (d, 1 H, J1,2 1.8 Hz, H-1II), 5.02 (dd, 1
H, J2,3 3.1, J3,4 9.8 Hz, H-3I), 4.85 (d, 1 H, J1,2 5.8 Hz,
H-1IV), 4.43 (dd, 1 H, J1,2 1.8, J2,3 3.1 Hz, H-2I), 4.35
(dd, 1 H, J2,3 3.2, J3,4 9.7 Hz, H-3II), 4.29–4.21 (m, 3
H), 3.96–3.89 (m, 4 H), 3.73 (dd, 1 H, J3,4=J4,5=9.8
Hz, H-4I), 3.60 (m, 1 H), 2.03 (s, 3 H, COCH3), 1.92 (s,
3 H, COCH3), 1.71 (s, 3 H, COCH3), 1.34 (d, 3 H, J5,6
6.2 Hz, H-6), 1.04 (d, 3 H, J5,6 6.3 Hz, H-6). Anal.
Calcd for C76H71Cl3N2O28: C, 58.26; H, 4.57. Found:
C, 58.37; H, 4.40.
pyranoside (25)
Pentasaccharide 24 (388 mg, 0.3 mmol) was dissolved in
satd NH3–MeOH (30 mL). After 96 h at rt, the reac-
tion mixture was concentrated, and the residue was
purified by chromatography on Sephadex LH-20
(MeOH) to afford 25 as a foamy solid (201 mg, 80.4%):
1
[h]D −44.0° (c 0.5, H2O); H NMR (400 MHz, D2O):
5.18 (s, 1 H, H-1), 4.96 (d, 1 H, J1,2 1.6 Hz, H-1), 4.82
(s, 1 H, H-1), 4.76 (d, 1 H, J1,2 6.1 Hz, H-1), 4.47 (d, 1
H, J1,2 7.8 Hz, H-1), 2.00 (s, 3 H, CH3CONH), 1.61 (m,
2 H, OCH2CH2CH3), 1.38 (d, 3 H, J5,6 6.0 Hz, H-6),
1.32 (d, 3 H, J5,6 6.3 Hz, H-6), 1.28 (d, 3 H, J5,6 6.2 Hz,
H-6), 0.93 (t, 3 H, J 7.4 Hz, OCH2CH2CH3); 13C NMR
(100 MHz, D2O): l 168.2, 106.5, 104.9,104.6, 103.5,
99.7, 19.1. MS (m/z) Calcd for C34H59NO22: 833.81
[M]+. Found: 856.90 [M+Na]+.
3.17. Allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-
D
-glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a-
rhamnopyranosyl-(1“4)-[2,3,4-tri-O-benzoyl-b-
xylopyranosyl-(1“2)]-a- -rhamnopyranoside (26)
L-
L-
L
3.19. Allyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-b-
glucopyranosyl-(1“3)-2,4-di-O-benzoyl-a- -rhamno-
pyranosyl-(1“4)-[2,3,4-tri-O-benzoyl-b- -xylopyran-
osyl-(1“2)-]3-O-acetyl-a- -rhamnopyranosyl-(1“3)-
2,4-di-O-benzoyl-a- -rhamnopyranoside (30)
D-
L
Compound 11(4.70 g, 5.0 mmol) and 17 (3.30 g, 5.0
mmol) were coupled under the same conditions as that
used for the preparation of 19 from 11 and 14, giving
26 as a foamy solid (6.30 g, 88.8%). [h]D +39.3° (c 1.0,
L
L
L
1
CHCl3); H NMR (400 MHz, CDCl3): l 8.12–7.22 (m,
Compound 29 (1.57 g, 1.0 mmol) and 6 (0.42 g, 1.0
mmol) were coupled under the same conditions as those
used for the preparation of 23 from 22 and 6, giving 30
(1.55 g, 85.2%) as a foamy solid: [h]D +98.5° (c 0.2,
29 H, 5 Ph, Phth), 5.75 (m, 1 H, OCH2CHꢀCH2),
5.71–5.67 (m, 2 H, H-3III, H-3IV), 5.48 (dd, 1 H, J1,2
1.8, J2,3 3.2 Hz, H-2II), 5.38 (d, 1 H, J1,2 8.3 Hz, H-1III),
5.33 (dd, 1 H, J1,2 8.3, J2,3 6.7 Hz, H-2IV), 5.28 (d, 1 H,
J1,2 1.8 Hz, H-1II), 5.26–5.22 (m, 2 H, H-4II, H-4III),
5.13–5.02 (m, 3 H, H-4IV, OCH2CHꢀCH2), 4.72 (d, 1
H, J1,2 6.4 Hz, H-1IV), 4.53 (s, 1 H, H-1I), 4.37 (dd, 1 H,
J2,3 3.2, J3,4 9.6 Hz, H-3II), 4.23–4.14 (m, 3 H), 3.96 (m,
1 H, OCH2CHꢀCH2), 3.91 (dd, 1 H, J2,3 2.9, J3,4 9.7
Hz, H-3I), 3.87–3.81 (m, 4 H), 3.70 (m, 1 H,
1
CHCl3); H NMR (400 MHz, CDCl3): 8.13–7.35 (m,
39 H, 7 Ph, Phth), 6.00 (m, 1 H, CH2CHꢀCH2), 5.47 (d,
1 H, J1,2 8.2 Hz, H-1), 5.15 (d, 1 H, J1,2 1.4 Hz, H-1),
5.01 (d, 1 H, J1,2 1.5 Hz, H-1), 4.88 (d, 1 H, J1,2 1.6 Hz,
H-1), 4.71 (d, 1 H, J1,2 6.0 Hz, H-1), 2.09 (s, 3 H,
COCH3), 1.99 (s, 3 H, COCH3), 1.89 (s, 3 H, COCH3),
1.78 (s, 3 H, COCH3), 1.31 (d, 3 H, J5,6 6.3 Hz, H-6),

J. Zhang, F. Kong / Carbohydrate Research 338 (2003) 19–27
27
1.26 (d, 3 H, J5,6 6.3 Hz, H-6), 0.92 (d, 3 H, J5,6 6.4 Hz,
H-6); 13C NMR (100 MHz, CDCl3): l 170.0, 169.4,
169.3, 169.0, 166.8, 165.6, 165.0, 164.9, 164.5, 164.4,
164.3, 164.2, 133.5, 133.4, 133.2, 133.1, 132.9, 132.8,
132.7, 132.5, 130.6, 129.6, 129.5, 129.4, 129.3, 129.2,
129.1, 129.0, 128.9, 128.8, 128.7, 128.5, 128.2, 128.1,
128.0, 127.9, 127.8, 127.6, 117.3, 99.3, 99.2, 98.5, 97.4,
96.4, 20.3, 20.2, 20.1, 19.9, 17.4, 17.2, 17.1. Anal. Calcd
for C97H93NO34: C, 64.13; H, 5.16. Found: C, 64.34; H,
5.20.
2 H, OCH2CH2CH3), 1.23 (d, 3 H, J5,6 6.2 Hz, H-6),
1.19 (d, 3 H, J5,6 6.3 Hz, H-6), 1.10 (d, 3 H, J5,6 6.4 Hz,
H-6), 0.81 (t, 3 H, J 7.6 Hz, OCH2CH2CH3); MS (m/z)
Calcd for C34H59NO22: 833.81 [M]+. Found: 856.85
[M+Na]+.
4. Supplementary material
The material is available from the authors on request.
Acknowledgements
3.20. Propyl 3,4,6-tri-O-acetyl-2-acetamido-2-deoxy-b-
D
-glucopyranosyl-(1“3)-2,4-di-O-acetyl-a-
pyranosyl-(1“4)-[2,3,4-tri-O-acetyl-b- -xylopyranosyl-
(1“2)]-3-O-acetyl-a- -rhamnopyranosyl-(1“3)-2,4-
di-O-acetyl-a- -rhamnopyranoside (31)
L-rhamno-
This work was supported by The Chinese Academy
of Sciences (KZCX3-J-08) and by The National Natu-
ral Science Foundation of China (Projects 30070185
and 39970864).
L
L
L
Compound 30 (910 mg, 0.5 mmol) was deblocked in
10% hydrazine–EtOH (40 mL) under reflux for 48 h,
and then acetylated with Ac2O (10 mL) in Py (15 mL)
to give 31 (530 mg, 81.8% for two steps) as a foamy
solid. [h]D −12.6° (c 1.0, CHCl3); 1H NMR (400 MHz,
CDCl3): 5.55 (bd, 1 H, J 6.6 Hz, NHCOCH3), 5.06 (d,
1 H, J1,2 7.4 Hz, H-1), 4.88 (s, 1 H, H-1), 4.74 (d, 1 H,
J1,2 1.6 Hz, H-1), 4.71 (d, 1 H, J1,2 1.7 Hz, H-1), 4.33
(d, 1 H, J1,2 6.6 Hz, H-1), 2.00, 2.18, 2.16, 2.08, 2.07,
2.05, 2.05, 2.04, 2.04, 2.01, 2.01, 1.90 (9 s, 36 H, 12
COCH3), 1.61 (m, 2 H, OCH2CH2CH3), 1.26 (d, 3 H,
J5,6 6.4 Hz, H-6), 1.23 (d, 3 H, J5,6 6.2 Hz, H-6), 1.19
(d, 3 H, J5,6 6.3 Hz, H-6), 0.95 (t, 3 H, J 7.4 Hz,
OCH2CH2CH3); 13C NMR (100 MHz, CDCl3): l 170.2,
170.1, 170.1, 170.0, 169.9, 169.6, 169.6, 169.4, 169.4,
169.4, 169.2, 168.7, 99.7, 98.9, 98.5, 98.0, 96.6. Anal.
Calcd for C56H81NO33: C, 51.89; H, 6.30. Found: C,
51.70; H, 6.41.
References
1. Shashkov, A. S.; Kocharova, N. A.; Knirel, Y. A.; Var-
banets, L. D.; Moskalenko, N. V.; Zdokhliy, A. V.
Bioorg. Khim. 1993, 19, 1089–1094.
2. Hayward, A. J. Appl. Bacteriol. 1964, 27, 265–277.
3. Okabe, N.; Goto, M. Shizuoka Diagaku Nogakubu
Kenkyn Hokoku. 1961, 11, 25–42.
4. Palleroni, N.; Doudoroff, M. J. Bacteriol. 1971, 107,
289–296.
5. Kocharova, N. A.; Knirel, Y. A.; Shashkov, A. S.; Nifan-
t’ev, N. E.; Kechetkov, N. K.; Varbanets, L. D.;
Moskalenko, N. V.; Brovarskaya, O. S.; Muras, V. A.;
Young, J. M. Carbohydr. Res. 1993, 250, 275–287.
6. Tommasi, N. D.; Piacente, S.; Gacs-Baitz, E.; De Si-
mone, F.; Pizza, C.; Aquino, R. J. Nat. Prod. 1998, 323,
61–66.
7. Jackson, G. E.; Ravenscroft, N.; Stephen, A. M. Carbo-
hydr. Res. 1990, 200, 409–418.
8. Mcneil, M.; Chatterjee, D.; Hunter, S. W.; Brenna, P. J.
Methods Enzymol. 1989, 179, 215–228.
9. Reimer, K. B.; Harris, S. L.; Varma, V.; Pinto, B. M.
Carbohydr. Res. 1992, 228, 399–414.
10. Albernas, J. M.; Harris, S. L.; Varma, V.; Pinto, B. M.
Carbohydr. Res. 1993, 245, 245–257.
3.21. Propyl 2-acetamido-2-deoxy-b-
(1“3)-a- -rhamnopyranosyl-(1“4)-[b-
(1“2)]-a- -rhamnopyranosyl-(1“3)-a-
pyranoside (32)
D
-glucopyranosyl-
-xylopyranosyl-
-rhamno-
L
L
L
L
11. Du, Y.; Kong, F. J. Carbohydr. Chem. 1999, 18, 655–
666.
12. Zhang, J.; Zhu, Y.; Kong, F. Carbohydr. Res. 2001, 336,
229–235.
13. Schmidt, R. R.; Kinzy, W. Ad6. Carbohydr. Chem.
Biochem. 1994, 50, 21–125.
14. Copeland, C.; Stick, R. V. Aust. J. Chem. 1978, 31,
1371–1374.
15. Auzanneau, F.-I.; Forooghian, F.; Pinto, B. M. Carbo-
hydr. Res. 1996, 291, 21–30.
16. Giss, R.; Payne, S.; Conant, R. J. Carbohydr. Chem.
1983, 2, 207–223.
Pentasaccharide 31 (400 mg, 0.31 mmol) was dissolved
in satd NH3–MeOH (50 mL). After 96 h at rt, the
reaction mixture was concentrated, and the residue was
purified by chromatography on Sephadex LH-20
(MeOH) to afford 32 as a foamy solid (213 mg, 82.8%):
1
[h]D −52.4° (c 0.5, H2O); H NMR (400 MHz, D2O):
5.03 (s, 1 H, H-1), 5.01 (d, 1 H, J1,2 1.0 Hz, H-1), 4.67
(s, 1 H, H-1), 4.66 (d, 1 H, J1,2 6.0 Hz, H-1), 4.31 (d, 1
H, J1,2 7.6 Hz, H-1), 1.93 (s, 3 H, CH3CONH), 1.52 (m,