Synthesis and application of spacer-modified L-fucose analogues

Article abstract of DOI:10.1081/CAR-100108277

Starting from 6-O-tert-butyldimethylsilyl-2,3;4,5-di-O-isopropylidenealdehydo-D-galactose (1), the carbon backbone elongated GDP-L-fucose analogue 15 bearing a chromophore tag at the end of a spacer was synthesized. Additionally, the analogues of 3-L-fuco

Full text of DOI:10.1081/CAR-100108277

J. CARBOHYDRATE CHEMISTRY, 20(7&8), 611–636 (2001)
SYNTHESIS AND APPLICATION OF SPACER-
MODIFIED L-FUCOSE ANALOGUES1
Andrej-Jakob Ott, Meinolf Brackhagen, Anahit Davtyan,
Birte Nolting, Hanna Boye, Astrid Schoknecht, and Christian Vogel*
University of Rostock, Department of Chemistry,
Division of Organic Chemistry, Buchbinderstraꢀe 9,
18055 Rostock, Germany
Dedicated to Professor Joachim Thiem on the occasion of his 60th birthday.
ABSTRACT
Starting from 6-O-tert-butyldimethylsilyl-2,3;4,5-di-O-isopropylidenealde-
hydo-D-galactose (1), the carbon backbone elongated GDP-L-fucose analogue
15 bearing a chromophore tag at the end of a spacer was synthesized. Addi-
tionally, the analogues of 3-L-fucosyllactose (29) and 2ꢁ-L-fucosyllactose (36),
where the fucosyl moiety is marked by a five atom alkyl chain at C-5, were pre-
pared as labeled oligosaccharides of human milk.
INTRODUCTION
As part of a program2 directed towards the synthesis of human milk oligosac-
charides containing fucose residues with various markers, we herein attempt to im-
prove the synthesis of a carbon backbone elongated L-fucose derivative bearing a
carboxy group at the end of the alkyl chain. Compound 8 was the base for the
preparation of a spacer-modified GDP-L-fucose analogue carrying a chromophore
marker. In addition, the glycosylation of various lactose derivatives with carbon
backbone elongated L-fucoses was investigated in order to obtain labeled oligosac-
charides of human milk. In connection with this, the first biological experiments
using these oligosaccharides will be discussed.
*Corresponding author. E-mail: christian.vogel@chemie.uni-rostock.de
611
Copyright © 2001 by Marcel Dekker, Inc.
www.dekker.com

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RESULTS AND DISCUSSION
The carbon backbone elongated L-fucose derivatives 9 and 10 are key inter-
mediates in our overall synthetic strategy for the preparation of GDP-L-fucose ana-
logues of human milk oligosaccharides bearing a chromophore tag (Scheme 2).
Previously, we were able to synthesize the protected D-galactose aldehyde 1 in
three steps from D-galactose diethyl dithioacetal in an overall yield of 65%.2 The
Wittig reaction with 4-carboxybutyl triphenylphosphonium bromide in the pres-
ence of lithium-bis-(trimethylsilyl) amide followed by esterification of the carboxy
function provided the alkene 3 in 58% yield (Scheme 1). Subsequent hydrogena-
tion (4, 94%), followed by cleavage of the TBDMS protecting group with tetra-n-
butylammonium fluoride (5, 98%), and oxidation by the Swern procedure gave the
carbon backbone elongated L-fucose derivative 6 (89%).
Removal of the isopropylidene group from 6 was accompanied by partial
cleavage of the ester bond (Scheme 2). Thus, after acetylation the ꢂ/ꢀ mixtures of
separated compounds 9 and 10 (ratio 1 : 1.5, 75%) were obtained in an overall yield
of 23% from D-galactose diethyl dithioacetal. An alternative route recently de-
scribed by us3 was comparatively successful, giving the target compound 9 in a
20% yield after the same number of synthetic steps. The free acid 10 was then used
for the synthesis of a chromophore labeled GDP-L-fucose analogue, whereas the
Scheme 1.

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613
Scheme 2.
ester 9 was converted into a glycosyl donor for the preparation of marked oligosac-
charides.
Compound 10 was therefore coupled with 4-amino-2,5-diethoxybenzanilide
(Fast Blue BB base) using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide
(EDCI)4 and 1-hydroxybenzotriazole (HOBt), giving the target compound 11 in
81% yield (Scheme 3).5,6 The ꢂ/ꢀ acetate 11 was treated with hydrogen bromide
Scheme 3.

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OTT ET AL.
in dichloromethane to give the glycosyl bromide 12 in 93% yield. Replacement of
bromine by phosphate was achieved using tetrabutylammonium phosphate.2,7 Af-
ter purification by column chromatography the acetylated phosphate 13 was iso-
lated in 43% yield. Without further characterization compound 13 was deacety-
lated and converted into the triethylammonium salt 14 in 60% yield (based on 13).
In the 1H NMR spectrum of 14 the vicinal coupling constant value J1,2 ꢃ 7.7 Hz
indicates clearly the ꢀ-glycosidic linkage of the pyranosyl phosphate which is a re-
quirement for biochemical activity.
To avoid the formation of a guanosine-5ꢁ-monophosphate dimer which can-
not be separated from the target compound 15, GMP-morpholidate9 was added in
portions to an excess of the fucosyl phosphate 14, providing the sugar nucleotide
15 in 28% yield. The analytical data of 15 are in complete agreement with the struc-
ture proposed. Thus, the coupling constant values 3J1,P ꢃ J1,2 ꢃ 7.6 Hz of galacto-
1
syl H-1 in the H NMR spectrum and the resonances of Gal-P at ꢄ ꢅ12.11 (d, J
ꢃ 19.5 Hz) Gal-P) and Rib-P at ꢄ ꢅ10.21 (d, J ꢃ 19.5 Hz) in the 31P NMR spec-
trum indicate clearly the stereochemistry at the diphosphate bridge. The enzymat-
ically catalyzed transfer of the chromophore labeled fucosyl moiety of 15 to a suit-
able glycosyl acceptor is currently under investigation.
For the synthesis of labeled oligosaccharides of human milk, the peracety-
lated L-fucose derivatives 9 and 16, bearing a simple carbon chain of five atoms at
C-5,2 were converted into the thioglycosides 17 and 18 in an analogous fashion as
described by R.K. Jain and K. L. Matta10 (Scheme 4). After deacetylation the re-
sulting compounds 19 and 20 were benzylated to provide the tri-O-benzyl thiogly-
cosides 21 and 22 in moderate yields (ca. 45%). Owing to these low yields, the
trimethylsilylation of 20 was used as a simple alternative for hydroxyl group pro-
tection11 to give 23 in 68% yield.
For the synthesis of a labeled 3-fucosyllactose (Scheme 5) the glycosylation
of the partially benzylated lactoside 2412 with glycosyl donor 21 was promoted by
freshly prepared13 iodonium di-sym-collidine perchlorate (IDCP)14 or dimethyl-
Scheme 4.

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615
Scheme 5.
(methylthio)sulfonium triflate (DMTST)15,16 to give the desired fully protected
trisaccharide 26 in comparable yields of 33% and 38%, respectively. The vicinal
coupling constant value J1,2 ꢃ 3.5 Hz in the 1H NMR spectrum and the C-1 signal
at ꢄ 96.93 in the 13C NMR spectrum of the fucosyl moiety proved the 1,2-cis-gly-
cosidic linkage. An exchange of the acceptor 24 by the partially benzylated benzyl
3ꢁ,4ꢁ-O-isopropylidene-ꢀ-lactoside 2517 and its glycosylation with 21 in a ratio of
one to one, promoted by DMTST, gave the trisaccharide 27 in a comparable 30%
yield or an 84% yield based on the recovered acceptor 25. The trisaccharides 26
and 27 were then taken through the requisite deprotection steps. The isopropyli-
dene group of 27 was removed by 80% acetic acid (60%). Catalytic hydrogenoly-
sis of 26 or 28 in ethanol/acetic acid in the presence of palladium-on-charcoal af-
forded the free trisaccharide 29 as an amorphous colorless solid in 90% yield.
For the synthesis of labeled 2ꢁ-fucosyllactoses (Scheme 6) an approach orig-
inally described by K. L. Matta and coworkers was used.18 After selective ben-
zoylation18 of the 2,3;5,6;3ꢁ,4ꢁ-tri-O-isopropylidenelactose dimethyl acetal,19,20
glycosylation of resulting acceptor 30 with glycosyl donor 21, promoted by
IDCP,21 provided the trisaccharide 31 in 46% yield after purification by MPLC.
The stereochemistry of the glycosidic linkage between the fucosyl residue and the
lactose was assigned based on the small coupling constant J1,2 ꢃ 3.2 Hz in the 1H
NMR spectrum and the signal for C-1 occurring at ꢄ 94.83 in the 13C NMR spec-
trum.
In the 13C NMR spectrum of a mixture of 31 and a slightly faster moving
(TLC) compound, probably the ꢀ-fucosyl isomer, additional signals in the
anomeric region were observed [ꢄ 102.56 (Fuc: C-1), 103.05 (Gal: C-1) and 105.25
(Glc: C-1)].

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Scheme 6.
After debenzoylation of 31 with methanolic sodium methoxide, the trisac-
charide 32 (84%) was deacetalated in aq 60% acetic acid at 60 °C to afford the tri-
O-benzyl trisaccharide 35 in 72% yield. Finally, catalytic hydrogenolysis of 35 in
glacial acetic acid and chromatographic purification provided the free trisaccharide
36 in a yield of 87% as a colorless powder.
Analogously the freshly prepared glycosyl donor 23 was coupled with ac-
ceptor 30 in the presence of IDCP to afford the partially trimethylsilylated trisac-
charide 33 in an excellent 78% yield (Scheme 6). Characteristic signals in the 1H
NMR spectrum appeared at ꢄ 5.29 (d, 1H, J1,2 ꢃ 3.7 Hz, Fuc: H-1) and in the 13
C
NMR spectrum at ꢄ 97.41 (Fuc: C-1), which confirm the assigned structure of 33.
Treatment of 33 with methanolic sodium methoxide led to a simultaneous cleav-
age of the benzoyl ester and the trimethylsilyl ether linkages in 81% yield. Finally,

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617
the deisopropylidenation of resulting 34 afforded an analog (37) of 2ꢁ-fucosyllac-
tose, where C-5 of the fucosyl moiety is derivatized with a five-atom spacer termi-
nating in a methoxycarbonyl group. In further experiments, we will use the trisac-
charide 37 for fluorescence marked fucosyllactose.
Recent results in a biological study22 indicated that 2ꢁ-fucosyllactose labeled
with an alkyl chain elongated fucose residue (36) was almost completely degraded,
most likely in the intestinal tract, when administered orally to three weeks old
suckling rats. No traces of this compound nor of the modified L-fucose were de-
tected in the faeces and only small amounts of 36 could be characterized in the
urine by high-pH anion-exchange chromatography with pulsed amperometric de-
tection.23 Surprisingly, a higher concentration of 36 in the rat milk does not lead to
a higher content in the urine of suckling rats. Nevertheless, this animal experiment
emphasized the supposition of an absorption pathway for human milk oligosac-
charides in breast-fed infants.24
EXPERIMENTAL
General methods. Melting points were determined with a Boetius micro
apparatus BHMK 05 (Rapido, Dresden) and are uncorrected. Optical rotations
were measured in a 2 cm cell with an automatic polarimeter “GYROMAT” (Dr.
Kernchen Co.). A Perkin-Elmer Model “Lambda 2” spectrometer was used for
measurement of UV-VIS spectra. NMR spectra were recorded with Bruker AC-
250 or ARX-300 spectrometers, at 250 MHz or 300 MHz for 1H and 62.9 MHz or
75.5 MHz for 13C, respectively. Chemical shifts are recorded relative to tetram-
ethylsilane (ꢄ ꢃ 0) as an internal standard. First order chemical shifts and coupling
constants were obtained from one-dimensional spectra, and assignment of proton
resonances was based on COSY experiments. Thin-layer chromatography (TLC)
was performed on precoated plates of silica gel (Merck, Silica Gel 60, F254, 0.25
mm) with the following solvent systems (v/v): (A) 10:1, (B) 9:1, (C) 5:1, (D) 4:1,
(E) 3:1, (F) 5:2, (G) 2:1, (H) 1:1, (I) 1:2 heptane-ethyl acetate, (J) 12:1, (K) 8:1,
(L) 4:1 ethyl acetate-methanol, (M) 5:2:1 ethyl acetate-methanol-water, (N) 5:1,
(O) 1:1, (P) 1:2 chloroform-methanol, (Q) 9:1 acetonitrile-water, and 2:1 2-
propanol-water. The spots were made visible by spraying with a methanolic 10%
H2SO4 solution and charring them for 3–5 min with a heat gun. Detection of ben-
zyl derivatives was effected by UV fluorescence. Preparative flash chromatogra-
phy, MPLC and HPLC was performed by elution from columns of slurry-packed
Silica Gel 60 (Merck, 40–63 ꢆm) or Nucleosil 100–7 (Knauer, 7.0 ꢆm), respec-
tively, using the above solvent systems. All solvents and reagents were purified
and dried according to standard procedures.25 After classical work up of the reac-
tion mixtures, the organic layers were dried over MgSO4, and then concentrated
under reduced pressure (rotary evaporator).
1-O-tert-Butyldimethylsilyl-2,3;4,5-di-O-isopropylidene-10-methoxycar-
bonyl-6,7,8,9,10-pentadeoxy-L-galacto-dec-6-enitol (3). To a stirred suspen-

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sion of (4-carboxybutyl)triphenylphosphonium bromide (50g, 113 mmol) in dry
tetrahydrofuran (100 mL) was added dropwise a 1 M solution of lithium
bis(trimethylsilyl)amide in dry tetrahydrofuran (200 mL, FLUKA) under argon at
room temperature. After stirring for 15 min, a solution of 1 (42.2 g, 110 mmol)2 in
dry tetrahydrofuran (60 mL) was slowly added and the yellow colored reaction
mixture was stirred for a further 30 min. The colorless mixture was then diluted
with water (300 mL) and concentrated under vacuum to a volume of 250 mL. To
the solution was added heptane (100 mL) and the precipitated salts were filtered
off. The phases were separated, the aqueous layer was washed with heptane (2 ꢇ
50 mL), and the organic layer and washings were combined. For esterification of
the carboxylic group, to the solution of 2 was added heptane (200 mL), chloroform
(100 mL), methyl iodide (20 mL, 320 mmol), tetrabutylammonium bromide (16 g,
50 mmol), and sodium hydrogen carbonate (8.3 g, 100 mmol). The suspension was
then vigorously stirred for 48 h at ambient temperature (TLC, solvent C, Rf 0.40).
The phases were separated and the aqueous phase was extracted with chloroform
(2 ꢇ 50 mL). The combined organic layers were washed with water (3 ꢇ 100 mL),
dried, and concentrated. The crude ester 3 (30 g, 58%) was used for the next step
without further purification. An analytical sample of 3 was obtained by HPLC (elu-
ent solvent C) as a colorless syrup: [ꢂ]D27 ꢈ6.0° (c 1.0, chloroform); H NMR
1
(CDCl3) ꢄ 0.06 [s, 6H, (CH3)2Si], 0.88 [s, 9H, (CH3)3C], 1.26, 1.28, 1.30 [3s, 12H,
2 ꢇ (CH3)2C], 1.64 (m, 2H, H-9, H-9ꢁ), 2.13 (m, 2H, H-8, H-8ꢁ), 2.24 (t, 2H, H-
10, H-10ꢁ), 3.56 (s, 3H, CO2CH3), 3.64 (dd, 1H, J1,1ꢁ ꢃ10.9 Hz, H-1), 3.68 (m, 1H,
H-4), 3.74 (dd, 1H, H-1ꢁ), 3.83 (m, 1H, H-2), 3.91 (m, 1H, H-5), 4.67 (m, 1H, H-
3), 5.37 (m, 1H, H-7), 5.52 (m, 1H, H-6); 13C NMR (CDCl3) ꢄ ꢅ5.48, ꢅ5.56
[(CH3)2Si], 18.20 [(CH3)3C], 24.85 (C-9), 26.77 [(CH3)3C], 26.95, 26.98, 27.01,
27.08 [2 ꢇ (CH3)2C], 27.07 (C-8), 33.16 (C-10), 51.14 (CO2CH3), 63.35 (C-1),
74.75 (C-3), 77.30 (C-5), 79.71 (C-2), 81.64 (C-4) 109.28, 109.33 [2 ꢇ (CH3)2C],
128.06(C-7), 131.96 (C-6); 173.53 (CO2CH3).
Anal. Calcd for C24H44O7Si (472.69): C, 60.98; H, 9.38. Found: C, 61.06;
H, 9.38.
1-O-tert-Butyldimethylsilyl-2,3;4,5-di-O-isopropylidene-10-methoxycar-
bonyl-6,7,8,9,10-pentadeoxy-L-galacto-decitol (4). The crude alkene 3 (25.1 g,
53 mmol) was dissolved in heptane (100 mL) and hydrogenated with H2 in the
presence of 10% Pd/C (1.2 g) at room temperature under atmospheric pressure. Af-
ter shaking overnight [TLC solvent C; during charring, the spot of the unsaturated
compound 3 (Rf 0.40) became black at once, whereas the spot of the saturated com-
pound 4 (Rf 0.50) changed more slowly from red-brown to black], the catalyst was
removed by centrifugation, and the solution was concentrated. The crude product
4 (23.7 g, 94%) was sufficiently pure for the next step. Processing by HPLC (elu-
24
ent solvent G) gave an analytical sample of 4 as a colorless syrup: [ꢂ]D ꢅ4.1°
1
(c 1.0, chloroform); H NMR (CDCl3) ꢄ 0.00 [s, 6H, (CH3)2Si], 0.82 [s, 9H,
(CH3)3C], 1.30, 1.33, 1.34, 1.35 [4s, 12H, 2 ꢇ (CH3)2C], 1.33–1.72 (6m, 8H, H-6,
H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.27 (t, 2H, H-10, H-10ꢁ), 3.57 (t, 1H,

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619
H-4), 3.62 (s, 3H, CO2CH3), 3.68 (dd, 1H, J1,1ꢁꢃ11.3 Hz, H-1), 3.82 (m, 1H, H-3),
3.85 (dd, 1H, H-1ꢁ), 3.90 (m, 1H, H-2), 3.98 (m, 1H, H-5); 13C NMR (CDCl3)
ꢄ ꢅ5.30, ꢅ5.45 [(CH3)2Si], 18.36 [(CH3)3C], 24.81 (C-9), 25.61 (C-7), 25.91
[(CH3)3C], 27.00, 27.06, 27.13, 27.38 [2 ꢇ (CH3)2C], 29.11 (C-8), 33.38 (C-6),
33.95 (C-10), 51.29 (COCH3), 63.35 (C-1), 74.48 (C-3), 80.48 (C-2), 81.31 (C-5),
81.89 (C-4) 108.77, 109.48 [2 ꢇ (CH3)2C], 173.03 (CO2CH3).
Anal. Calcd for C24H46O7Si (474.71): C, 60.72; H, 9.77. Found: C, 60.93; H,
9.64.
2,3;4,5-Di-O-isopropylidene-10-methoxycarbonyl-6,7,8,9,10-pen-
tadeoxy-L-galacto-decitol (5). To a vigorously stirred solution of the tert-
butyldimethylsilyl derivative 4 (23.7 g, 50 mmol) in acetone (100 mL) was added
tetra-n-butylammonium fluoride trihydrate (24.0 g, 76 mmol). After 4 h at ambient
temperature (TLC, solvent H, Rf 0.45), the solution was diluted with heptane (200
mL), concentrated to a volume of about 100 mL to remove acetone, and then di-
luted with chloroform (50 mL). The organic layer was washed successively with
water (50 mL), aq sat NaHCO3 (2 ꢇ 50 mL), water (2 ꢇ 50 mL), dried, and con-
centrated. The residue was purified by column chromatography (eluent solvent G)
to provide 5 (17.7 g, 98%) as a colorless syrup: [ꢂ]D23 ꢅ13.5° (c 1.0, chloroform);
1H NMR (CDCl3) ꢄ 1.17, 1.19 1.21, 1.23 [4s, 12H, 2 ꢇ (CH3)2C], 1.25–1.58 (6m,
8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.14 (t, 2H, H-10, H-10ꢁ), 2.82
(dd, 1H, OH), 3.40 (dd, 1H, H-4), 3.48 (s, 3H, CO2CH3), 3.53 (m, 1H, H-1), 3.55
(m, 1H, H-3), 3.64 (m, 1H, H-1ꢁ), 3.77 (m, 1H, H-5), 3.87 (m, 1H, H-2); 13C NMR
(CDCl3) ꢄ 24.43 (C-9), 25.20 (C-7), 26.54 (two signals are isochronic), 26.81,
27.00 [2 ꢇ (CH3)2C], 28.67 (C-8) 32.76 (C-6), 33..53 (C-10), 51.99 (CO2CH3),
62.33 (C-1), 78.49 (C-3), 80.53 (C-5), 80.92 (C-2), 81.21 (C-4), 108.70, 109.43 [2
x(CH3)2C], 173.69 (CO2CH3).
Anal. Calcd for C18H32O7 (360.45): C, 59.98; H, 8.95. Found: C, 60.07; H,
9.01.
2,3;4,5-Di-O-isopropylidene-10-methoxycarbonyl-6,7,8,9,10-pen-
tadeoxy-L-galacto-decose (6). Dimethyl sulfoxide (9.5 mL, 134 mmol) was
added dropwise to a stirred solution of oxalyl chloride (4.8 mL, 56 mmol) in dry
dichloromethane (40 mL) at ꢅ78°C, under an argon atmosphere. After the mixture
had been stirred for 30 min, a solution of the sugar alcohol 5 (18.0 g, 50 mmol) in
dry dichlormethane (50 mL) was added dropwise at ꢅ78°C. Stirring was contin-
ued for another 30 min before triethylamine (17 mL, 122 mmol) was added drop-
wise. The mixture was warmed to room temperature and the solution was then di-
luted by addition of heptane (280 mL). The organic solution was washed with
ice-water (2 ꢇ 80 mL), cold aq 1 M hydrochloric acid (2 ꢇ 80 mL), ice-water (80
mL), cold aq sat NaHCO3 (2 ꢇ 80 mL), ice-water (2 ꢇ 80 mL), dried, and con-
centrated. An analytical sample was obtained by HPLC (eluent solvent G), whereas
the main part of 6 (16.0 g, 89%, TLC, solvent H, Rf 0.50) was used without further
purification, colorless syrup: [ꢂ]D21 ꢅ36.3° (c 2.0, chloroform); 1H NMR (CDCl3)

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ꢄ 1.20, 1.22 1.33, 1.40 [4s, 12H, 2 ꢇ (CH3)2C], 1.32–1.60 (6m, 8H, H-6, H-6ꢁ, H-
7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.25 (t, 2H, H-10, H-10ꢁ), 3.58 (s, 3H, CO2CH3),
3.65 (t, 1H, H-4), 3.90 (m, 1H, H-5), 4.03 (dd, 1H, H-3), 4.40 (dd, 1H, H-2), 9.69
(d, H-1); 13C NMR (CDCl3) ꢄ 24.72 (C-9), 25.46 (C-7), 26.20, 27.00, 27.15, 28.96
[2 ꢇ (CH3)2C], 28.96 (C-8), 33.14 (C-6), 33.86 (C-10), 51.20 (CO2CH3), 77.79
(C-3), 79.80 (C-5), 80.81 (C-4), 83.14 (C-2), 109.13, 111.71 [2 ꢇ (CH3)2C],
173.89 (CO2CH3), 199.72 (C-1).
Anal. Calcd for C18H30O7 (358.43): C, 60,32; H, 8,44. Found: C, 60.59, H,
8.46.
Deisopropylidenation and acetylation of compounds 6. Dowex 50 [Hꢈ]
(20 g) was added to a solution of 6 (17.9 g, 50 mmol) in acetonitrile (200 mL) and
water (20 mL) and the mixture was stirred for 3 h at 70 °C. After filtration the fil-
trate was concentrated to a volume of 15 mL, aq 90% trifluoroacetic acid (40 mL)
was then added, and the solution was kept for 30 min at ambient temperature.
When the reaction was complete (TLC, solvent N), the solution was diluted with
toluene (50 mL) and concentrated. Traces of trifluoroacetic acid were removed by
repeated coevaporation with toluene (3 ꢇ 100 mL), and the residue was finally
lyophilized to provide 7 and 8 (13.0 g). Without further characterization a solution
of compounds 7 and 8 (the whole amount of the preceding step) in dry acetonitrile
(30 mL) was added dropwise to a solution of acetic anhydride (90 mL) and aq 70%
perchloric acid (0.9 mL) at 0°C. The solution was kept for 40 min at room temper-
ature and then slowly poured under vigorous stirring into ice-water (2 L). After
stirring for 2 h the aqueous layer was extracted with solvent heptane - ethyl acetate
2 : 1 (2 ꢇ 150 mL). The combined organic layers were washed with water
(4 ꢇ 50 mL), dried and concentrated. The residue was purified by MPLC (eluent
ethyl acetate gradient 25% → 100% in heptane). Analytical samples of 9 and 10
were obtained by HPLC using again ethyl acetate gradient 25% → 100% in hep-
tane as eluent.
1,2,3,4-Tetra-O-acetyl-10-methoxycarbonyl-6,7,8,9,10-ꢂ-L-galacto-de-
copyranose (9ꢂ). (4.5 g, 20%, TLC, solvent G, Rf 0.42), colorless syrup: [ꢂ]D27
ꢅ111.3° (c 1.0, chloroform); 1H NMR (CDCl3) ꢄ 1.24–1.59 (6m, 8H, H-6, H-6ꢁ,
H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.96, 1.98, 2.11, 2.13 (4s, 12H, 4 ꢇ OCOCH3),
2.24 (t, 2H, H-10, H-10ꢁ), 3.62 (s, 3H, CO2CH3), 3.99 (m, 1H, H-5); 5.26 (m, 1H,
H-4), 5.27 (m, 1H, H-3), 5.34 (m, 1H, H-2), 6.30 (d, 1H, J1,2 ꢃ 0.1 Hz, H-1); 13
C
NMR (CDCl3) ꢄ 20.44, 20.54, 20.64, 20.78 (4 ꢇ OCOCH3), 24.54 (C-9), 24.74
(C-7), 28.75 (C-8) 29.78 (C-6), 33.78 (C-10), 51.33 (CO2CH3), 68.13 (C-4), 69.25
(C-3), 70.92 (C-2, C-5, two signals are isochronic), 89.90 (C-1), 168.96, 169.31,
170.03, 170.31 (4 ꢇ OCOCH3), 173.86 (CO2CH3).
Anal. Calcd for C20H30O11 (446.45): C, 53.81; H, 6.77. Found: C, 53.69; H,
6.56.
1,2,3,4-Tetra-O-acetyl-10-methoxycarbonyl-6,7,8,9,10-ꢀ-L-galacto-de-
copyranose (9ꢀ). (2.2 g, 10%, TLC, solvent G, Rf 0.40), colorless crystals: mp

ORDER
REPRINTS
SPACER-MODIFIED L-FUCOSE ANALOGUES
621
75 °C (from ethyl acetate - heptane); [ꢂ]D22 ꢅ24.0° (c 1.5, chloroform); 1H NMR
(CDCl3) ꢄ 1.28–1.60 (6m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.94,
1.99, 2.07, 2.13 (4s, 12H, 4 ꢇ OCOCH3), 2.24 (t, 2H, H-10, H-10ꢁ), 3.61 (s, 3H,
COCH3), 3.68 (m, 1H, H-5), 5.01 (m, 1H, J3,4 ꢃ 3.6 Hz, H-3), 5.26 (m, 1H, H-4),
5.27 (dd, 1H, J2,3 ꢃ10.4 Hz, H-2), 5.60 (d, 1H, J1,2 ꢃ 8.2 Hz, H-1); 13C NMR
(CDCl3) ꢄ 20.45, 20.54, 20.64, 20.73 (4 ꢇ OCOCH3), 24.56 (C-9), 24.83 (C-7),
28.64 (C-8), 29.84 (C-6), 33.81 (C-10), 51.34 (CO2CH3), 68.16(C-2), 69.04 (C-4),
71.33 (C-3), 74.16 (C-5), 92.34 (C-1), 168.99, 169.32, 169.87, 170.31
(4 ꢇ OCOCH3), 173.89 (CO2CH3).
Anal. Calcd for C20H30O11 (446.45): C, 53.81; H, 6.77. Found: C, 53.82;
H, 6.49.
1,2,3,4-Tetra-O-acetyl-10-carboxy-6,7,8,9,10-ꢂ-L-galacto-decopyranose
(10ꢂ). (6.5 g, 30%, TLC, solvent G, Rf 0.17), colorless syrup: [ꢂ]D25 ꢅ106.7° (c
0.8, chloroform); 1H NMR (CDCl3) ꢄ 1.31–1.56 (6m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-
8, H-8ꢁ, H-9, H-9ꢁ), 1.93, 1.94, 2.04, 2.10 (4s, 12H, 4 ꢇ OCOCH3), 2.25 (t, 2H,
H-10, H-10ꢁ), 3.89 (m, 1H, H-5); 5.23 (m, 1H, H-3), 5.25 (m, 1H, H-4), 5.31 (m,
1H, H-2), 6.27 (d, 1H, J1,2 ꢃ1.8 Hz, H-1); 13C NMR (CDCl3) ꢄ 20.44, 20.52,
20.62, 20.72 (4 ꢇ OCOCH3), 24.30 (C-9), 24.71 (C-7), 28.66 (C-8) 29.77 (C-6),
33.68 (C-10), 66.88 (C-3), 67.94 (C-4), 69.61 (C-2), 70.92 (C-5), 89,91 (C-1),
169.05, 169.95, 170.12, 170.43 (4 ꢇ OCOCH3), 178.84 (CO2H).
Anal. Calcd for C19H28O11 (432.42): C, 52.77; H, 6.53. Found: C, 52.63; H,
6.31.
1,2,3,4-Tetra-O-acetyl-10-carboxy-6,7,8,9,10-ꢀ-L-galacto-decopyranose
(10ꢀ). (3.3 g, 15%, TLC, solvent G, Rf 0.15), colorless crystals: mp 136 °C (from
ethyl acetate - heptane); [ꢂ]D22 ꢅ20.4° (c 1.8, chloroform); H NMR (CDCl3) ꢄ
1
1.27–1.55 (6m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.92, 1.96, 2.04,
2.10 (4s, 12H, 4 ꢇ OCOCH3), 2.25 (t, 2H, H-10, H-10ꢁ), 3.67 (m, 1H, H-5), 5.01
(dd, 1H, J3,4 ꢃ 3.4 Hz, H-3), 5.23 (dd, 1H, J2,3 ꢃ 10.4 Hz, H-2), 5.24 (m, 1H,
H-4), 5.59 (d, 1H, J1,2 ꢃ 8.3 Hz, H-1); 13C NMR (CDCl3) ꢄ 20.43, 20.54 (two sig-
nals are isochronic), 20.71 (4 ꢇ OCOCH3), 24.28 (C-9), 24.80 (C-7), 28.53 (C-8)
29.79 (C-6), 33.68 (C-10), 68.17 (C-2), 69.08 (C-4), 71.31 (C-3), 74.12 (C-5),
92.31 (C-1), 169.06, 169.41, 169.94, 170.40 (4 ꢇ OCOCH3), 178.96 (CO2H).
Anal. Calcd for C19H28O11 (432.42): C, 52.77; H, 6.53. Found: C, 52.84;
H, 6.24.
1,2,3,4-Tetra-O-acetyl-10-(4-benzamido-2,5-diethyloxyphenylaminocar-
bonyl)-6,7,8,9,10-pentadeoxy-ꢂ,ꢀ-L-galacto-decopyranose (11ꢂ,ꢀ). Molecu-
lar sieves (4 Å, 10 g) were added to a stirred solution of 1-ethyl-3-(3-dimethy-
laminopropyl)carbodiimide (EDCI, 3.3 g, 17 mmol) and 1-hydroxybenzotriazole
(2.7 g, 17 mmol) in dry dichloromethane (48 mL) and dry N,N-dimethylformamide
(12 mL). After 30 min a solution of 10ꢂ,ꢀ (3.5g 8 mmol) and 4-amino-2,5-di-
ethoxybenzanilide (6.0 g, 20 mmol) in dry dichloromethane (32 mL) and dry N,N-
dimethylformamide (8 mL) was added. After stirring overnight at room tempera-

ORDER
REPRINTS
622
OTT ET AL.
ture (TLC, solvent I, Rf 0.40), the mixture was diluted with heptane (400 mL) and
chloroform (200 mL) and the organic layer washed successively with ice-water
(2 ꢇ 200 mL), cold aq 1 M hydrochloric acid (2 ꢇ 200 mL), ice-water (200 mL),
cold aq sat NaHCO3 (2 ꢇ 200 mL), ice-water (2 ꢇ 200 mL), dried, and concen-
trated. The crude product was purified by column chromatography (eluent ethyl ac-
etate gradient 50% → 75% in heptane) to yield 11ꢂ,ꢀ ( 81%). An analytical sam-
ple was obtained by HPLC using ethyl acetate gradient 50% → 75% in heptane as
eluent.
1,2,3,4-Tetra-O-acetyl-10-(4-benzamido-2,5-diethyloxyphenylaminocar-
bonyl)-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranose (11ꢂ). Colorless
crystals: mp 110°C (from ethyl acetate - heptane),[ꢂ]1D9 ꢅ84.0° (c 2.0, chloroform);
1H NMR (CDCl3) ꢄ 1.40, 1.68 (2m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-
9ꢁ), 1.43 (t, 6H, 2 ꢇ CH3CH2O), 1.97, 1.99, 2.10, 2.13 (4s, 12H, 4 ꢇ OCOCH3),
2.35 (t, 2H, H-10, H-10ꢁ), 4.02 (m, 1H, H-5), 4.14 (dq, 4H, CH3CH2O), 5.28 (m,
1H, H-3), 5.31 (m, 1H, H-2), 5.37 (m, 1H, H-4), 6.33 (d, 1H, J1,2 ꢃ1.7 Hz, H-1),
7.48, 7.52, 7.86, 8.25, [3m, 1s, 7H, C6H5CO, C6H2(OC2H5)2], 7.76, 8.58 (2s, 2H,
2 ꢇ NH); 13C NMR (CDCl3) ꢄ 14.92, 14.95 (2 ꢇ OCH2CH3), 20.51, 20.60, 20.85
(4 ꢇ OCOCH3, two signals are isochronic), 24.94 (C-9), 25.12 (C-7), 28.80 (C-8),
29.88 (C-6), 37.67 (C-10), 64.99, 65.05 (2 ꢇ CH3CH2O), 66.72 (C-3), 67.98 (C-
4), 69.62 (C-2), 71.05 (C-5), 89.96 (C-1), 104.26, 104.35, 123.35, 123.62, 126.85,
128.81, 131.68, 135.19, 140.67, 141.15 [C6H5CO, C6H2(OC2H5)2, 4 signals are
isochronic], 164.81 (C6H5CO), 169.02 (CONH), 169.87, 170.10, 170.40, 170.77 (4
ꢇ OCOCH3).
Anal. Calcd for C36H46N2O13 (714.77): C, 60.49; H, 6.49; N, 3.92. Found: C,
60.49; H, 6.50; N, 3.84.
1,2,3,4-Tetra-O-acetyl-10-(4-benzamido-2,5-diethyloxyphenylaminocar-
bonyl)-6,7,8,9,10-pentadeoxy-ꢀ-L-galacto-decopyranose (11ꢀ). Colorless
crystals: mp 133°C (from ethyl acetate - heptane),[ꢂ]1D9 ꢅ20.0° (c 2.0, chloroform);
1H NMR (CDCl3) ꢄ 1.39, 1.69 (2m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-
9ꢁ), 1.39 (t, 6H, 2 ꢇ CH3CH2O), 1.96, 2.00, 2.08, 2.14 (4s, 12H, 4 ꢇ OCOCH3),
2.35 (t, 2H, H-10, H-10ꢁ), 3.70 (m, 1H, H-5), 4.13 (dq, 4H, CH3CH2O), 5.03 (dd,
1H, J3,4 ꢃ 3.4 Hz, H-3), 5.27 (m, 1H, H-4), 5.29 (dd, 1H, J2,3 ꢃ 10.4 Hz, H-2), 5.63
(d, 1H, J1,2 ꢃ8.2 Hz, H-1), 7.48, 7.86, 8.20, 8.30, [2m, 2s, 7H, C6H5CO,
C6H2(OC2H5)2], 7.75, 8.58 (2s, 2H, 2 ꢇ NH); 13C NMR (CDCl3) ꢄ 14.96
(2 ꢇ CH3CH2O, two signals are isochronic), 20.77, 20.87, 20.94 (4 ꢇ OCOCH3,
two signals are isochronic), 24.30 (C-9), 24.71 (C-7), 28.79 (C-8), 29.90 (C-6),
37.68 (C-10), 64.90, 64.97 (2 ꢇ CH3CH2O), 68.05 (C-4), 68.99 (C-2), 71.16
(C-5), 71.34 (C-3), 92.32 (C-1), 104.07, 104.19, 123.21, 123.54, 126.86, 128.84,
131.73, 135.12, 140.07, 140.59 [C6H5CO, C6H2(OC2H5)2, 4 signals are
isochronic], 164.82 (C6H5CO), 169.14 (CONH), 169.45, 170.03, 170.44, 170.88
(4 ꢇ OCOCH3).
Anal. Calcd for C36H46N2O13 (714.77): C, 60.49; H, 6.49; N, 3.92. Found: C,
60.74; H, 6.52; N, 3.97.

ORDER
REPRINTS
SPACER-MODIFIED L-FUCOSE ANALOGUES
623
2,3,4-Tri-O-acetyl-10-(4-benzamido-2,5-diethyloxyphenylaminocar-
bonyl)-6, 7, 8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl bromide (12).
A
solution of water (0.33 mL, 18.2 mmol) in glacial acetic acid (1.6 mL) was added
dropwise to a stirred solution of 11 (4.5 g, 6.2 mmol) in dry dichloromethane (10
mL), acetic anhydride (0.6 mL, 6.2 mmol), glacial acetic acid (1.6 mL) and acetyl
bromide (1.4 mL, 18.2 mmol) at 5 °C. After stirring for two hours at ambient tem-
perature (TLC, solvent I, Rf 0.50), heptane (60 mL) and chloroform (30 mL) were
added, and the organic layer was successively washed with ice-water (40 mL), cold
sat aq NaHCO3 (2 ꢇ 40 mL), ice-water (2 ꢇ 40 mL), dried, and concentrated. The
bromide 20 (4.3 g, 93%; syrup) was immediately used for the next step without fur-
ther purification: 1H NMR (CDCl3), ꢄ 1.41, 1.69 (2m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ,
H-8, H-8ꢁ, H-9, H-9ꢁ), 1.43 (t, 6H, 2 ꢇ CH3CH2O), 1.99, 2.09, 2.14 (3s, 9H,
3 ꢇ OCOCH3), 2.37 (t, 2H, H-10, H-10ꢁ), 4.15 (dq, 4H, CH3CH2O), 4.16 (m, 1H,
H-5), 5.01 (m, 1H, H-2), 5.38 (dd, 1H, J3,4 ꢃ 3.4 Hz, H-3), 5.39 (m, 1H, H-4), 6.69
(d, 1H, J1,2 ꢃ 4.0 Hz, H-1), 7.50, 7.86, 8.20, 8.30, [2m, 2s, 7H, C6H5CO,
C6H2(OC2H5)2], 7.76, 8.59 (2s, 2H, 2 ꢇ NH); 13C NMR (CDCl3) ꢄ 14.94
(2 ꢇ CH3CH2O, two signals are isochronic), 20.53, 20.58, 20.70 (3 ꢇ OCOCH3),
24.74, 25.11, 28.63, 29.49 (C-6, C-7, C-8, C-9), 37.69 (C-10), 65.07 (2
ꢇ CH3CH2O, two signals are isochronic), 68.01 (C-2), 68.54 (C-3), 69.19 (C-4),
73.42 (C-5), 89.40 (C-1), 104.27, 104.38, 123.50, 124.00, 126.85, 128.80, 131.66,
135.00, 140.50, 141.15 [C6H5CO, C6H2(OC2H5)2, 4 signals are isochronic],
164.90 (C6H5CO), 169.90 (CONH), 170.00, 170.50, 171.30 (3 ꢇ OCOCH3).
Bis(triethylammonium) 10-(4-benzamido-2,5-diethyloxyphenylamino-
carbonyl)-6,7,8,9, 10-pentadeoxy-ꢀ-L-galacto-decopyranos-1-yl phosphate
(14). A solution of glycosyl bromide 12 (4.35 g, 5.9 mmol) in dry acetonitrile (30
mL) was added to a stirred mixture of tetrabutylammonium phosphate (4.0 g, 11.8
mmol) and ground molecular sieves (4Å) in dry acetonitrile (60 mL) at 0 °C under
an argon atmosphere in the dark. After 30 min at 0°C stirring was continued for a
further 1.5 h at ambient temperature (TLC, solvent Q, Rf 0.40). The molecular
sieves were then filtered off and the filtrate was concentrated. The purification of
the crude material by column chromatography (3.0 ꢇ 40 cm; eluent linear gradi-
ent ethyl acetate-methanol-triethylamine 100:0:1→70:30:1 v,v,v) provided 13 (2.3
g, 43%). Freshly distilled cyclohexylamine (30 mL) was added to a solution of the
triacetate 13 (2.3 g, 2.4 mmol) in dry methanol (30 mL), without the triacetate be-
ing characterized further. The reaction mixture was refluxed for two hours under
argon, cooled and concentrated. The residue was dissolved in water (600 mL), the
aqueous layer washed with heptane-chloroform (2:1, 5 ꢇ 50 mL), concentrated to
a volume of about 150 mL and lyophilized. The galactodecopyranosyl phosphate
was converted to the triethylammonium salt by loading onto Dowex 50-X8
(3 ꢇ 45 cm; 200–400 mesh, Et3NHꢈ) ion-exchange resin in water and eluting with
water (2 mL/min). Fractions containing the product were pooled and lyophilized to
provide 14 (1.2 g, 60%, based on 13), colorless powder: [ꢂ]D27 ꢅ17.6° (c 0.6,
1
methanol); H NMR (CD3OD) ꢄ 1.30 [m, 18H, N(CH2CH3)3], 1.43 [m, 6H, 2
ꢇ CH3CH2O], 1.47, 1.72 (2m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ),

ORDER
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624
OTT ET AL.
2.45 (t, 2H, H-10, H-10ꢁ), 3.19 [m, 12H, 2 ꢇ N(CH2CH3)3], 3.45 (m, 1H, H-5),
3.50 (m, 1H, H-3), 3.53 (m, 1H, H-2), 3.67 (d, 1H, J3,4 ꢃ 3.0 Hz, J4,5 ꢀ0.0 Hz, H-
4), 4.09 (m, 4H, CH3CH2O), 4.85 (t, 1H, 3J1,P ꢃ J1,2 ꢃ 7.7 Hz, H-1), 7.52, 7.58,
7.78, 7.86, 7.90 [3m, 2s, 7H, C6H5CO, C6H2(OC2H5)2]; 13C NMR (CD3OD) ꢄ 9.19
[N(CH2CH3)3], 15.23 (2 ꢇ CH3CH2O, two signals are isochronic), 26.58, 26.85,
30.30, 31.59 (C-6, C-7, C-8, C-9), 37.83 (C-10), 47.11 [N(CH2CH3)3], 66.21
(2 ꢇ CH3CH2O, two signals are isochronic), 71.60 (C-4), 74.30 (J2,P ꢃ 3.7 Hz,
C-2), 75.44 (C-3), 76.50 (C-5), 99.84 (J1,P ꢃ 2.1 Hz, C-1), 108.39, 108.49, 124.84,
125.40, 128.20, 129.88, 136.05, 138.95, 145.15, 145.42 [C6H5CO, C6H2(OC2H5)2,
4 signals are isochronic], 171.00 (C6H5CO), 177.44 (CONH); 31P NMR (CD3OD)
ꢄ 3.53.
For this ionic compound no microanalysis was performed, because the con-
centration of the counterions was not exactly defined.
Bis(ammonium) 10-(4-benzamido-2,5-diethyloxyphenylaminocarbo-
nyl)-6,7,8,9,10-pentadeoxy-ꢀ-L-galacto-decopyranos-1-yl guanosine 5-diphos-
phate (15). After stirring a suspension of galactodecopyranosyl phosphate 14
(829 mg, 1.0 mmol) and molecular sieves (4 Å,1.0 g) in dry pyridine (20 mL) under
an argon atmosphere for 30 min, guanosine 5ꢁ-monophosphomorpholidate
4-morpholine-N,N-dicyclohexylcarboxamidine salt was added in three portions
(200 mg, 150 mg and 120 mg, total 0.65 mmol) combined in each case with the ad-
dition of molecular sieves (500 mg) at room temperature in an interval of 20 h. Af-
ter the last addition the reaction mixture was stirred for a further 20 h (TLC, sol-
vent R, Rf 0.20–0.50), filtered, coconcentrated with water to remove pyridine,
concentrated to a volume of 120 mL and lyophilized. A part of the crude product
15 (200 mg of a total of 1.8 g) was passed through a column of Biogel P-2 (3.5 ꢇ
90 cm; Bio Rad, 45–90 ꢆm; 0.5 mL/min; 6 mL fractions) using aq 0.25 M
NH4HCO3 as the eluent. The carbohydrate fractions were pooled and lyophilized.
The treatment of the whole amount of the crude diphosphate as described above
provided analytically pure 15 (183 mg, 28% yield based on guanosine 5ꢁ-
monophosphomorpholidate 4-morpholine-N,N-dicyclohexylcarboxamidine salt)
as a colorless powder: [ꢂ]D23 ꢅ19.8° (c 0.33, water); UV ꢉ 310 nm (ꢊ 6400 L mol-
1 cm-1, water); 1H NMR (D2O) ꢄ 1.44 [m, 6H, 2 ꢇ CH3CH2O], 1.45, 1.70 (2m, 8H,
H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.42 (t, 2H, H-10, H-10ꢁ), 3.62 (m,
1H, H-5), 3.68 (t, 1H, J2,3 ꢃ 7.6 Hz, H-2) 3.72 (dd, 1H, J3,4 ꢃ 3.1 Hz, H-3), 3.86
(m, 1H, H-4), 4.02 (m, 4H, CH3CH2O), 4.26 (m, 2H, Rib: H-5), 4.36 (m, Rib: H-
4), 4.54 (dd, 1H, J3,4 ꢃ 3.5 Hz, Rib: H-3), 4.74 (m, 1H, Rib: H-2), 4,91 (t, 1H, 3J1,P
ꢃ J1,2 ꢃ 7.6 Hz, H-1), 5.88 (d, 1H, J1,2 ꢃ 6.4 Hz, Rib: H-1), 7.40, 7.58, 7.64, 7.70,
7.86 [3m, 2s, 7H, C6H5CO, C6H2(OC2H5)2], 8.08 (s, 1H, G: H-8); 13C NMR (D2O)
ꢄ 15.21, 15.24 (2 ꢇ CH3CH2O), 25.68, 26.19, 29.28, 30.56 (C-6, C-7, C-8, C-9),
37.37 (C-10), 66.35 (Rib: C-5), 66.62 (2 ꢇ CH3CH2O, two signals are isochronic),
70.87 (C-4), 71.48 (Rib: C-3), 72.56 (J ꢃ 7.6 Hz, C-2), 73.78 (C-3), 75.04 (Rib: C-
2), 76.36 (C-5), 84.79 (d, J ꢃ 9.3 Hz, Rib: C-4), 88,08 (Rib: C-1), 99.67 (C-1),
108.80, 109.39, 124.31, 124.45, 128.00, 129.92, 133.51, 144.28, 144.48 [C6H5CO,
C6H2(OC2H5)2, 6 signals are isochronic], 134.30, 138.20, 152.50, 154.69, 159,63

ORDER
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SPACER-MODIFIED L-FUCOSE ANALOGUES
625
(G: C-2, C-4, C-5, C-6, C-8), 168.30 (CONH), 176.22 (C6H5CO); 31P NMR (D2O)
ꢄꢅ12.11 (d, J ꢃ 19.5 Hz, Gal-P), ꢅ10.21 (d, J ꢃ 19.5 Hz, Rib-P).
Anal. Calcd for C38H57N9O19P2 (1005.87): C, 45.38; H, 5.71, N, 12.53; P,
6.16. Found: C, 45.11; H, 5.97; N, 13.00; P, 6.05.
Transformation of 9 and 16 into the acetylated methyl thioglycosides 17
and 18. To a solution of 9 (5.8 g, 15 mmol) or 1,2,3,4-tetra-O-acetyl-6,7,8,9,10-
pentadeoxy-L-galacto-decopyranose (16, 5.8 g, 15 mmol) in dry dichloromethane
(25 mL) were added S-trimethylsilylmethylmercaptan (5 mL, 34.4 mmol) and
trimethylsilyltriflate (2.5 mL, 13.8 mmol). After stirring for 24 h under argon at-
mosphere followed by TLC, the reaction mixture was treated with N-ethyldiiso-
propylamine (3 mL), diluted with chloroform (35 mL) and heptane (120 mL), and
the organic layer washed with water (3 ꢇ 90 mL), dried and concentrated. The
crude products were purified by MPLC (eluent ethyl acetate gradient 10% → 20%
in heptane).
Methyl 2,3,4-tri-O-acetyl-6,7,8,9,10-pentadeoxy-1-thio-ꢀ-L-galacto-de-
copyranoside (17). (4.7 g, 83%, TLC, solvent H, Rf 0.46), colorless syrup:[ꢂ]D22
ꢅ15.2° (c 1.0, chloroform); 1H NMR (CDCl3) ꢄ 0.85 (t, 3H, H-10, H-10ꢁ, H-10ꢋ),
1.25, 1.40, 1.60 (3m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.96, 2.04,
2.15, 2.18 (4s, 12H, 3 ꢇ OCOCH3, SCH3), 3.59 (m, 1H, H-5), 4.35 (d, 1H, J1,2
ꢃ 9.8 Hz, H-1), 5.02 (dd, 1H, J3,4 ꢃ 3.3 Hz, H-3), 5.20 (t, 1H, H-2), 5.30 (dd, 1H,
J4,5 ꢃ 2.2 Hz, H-4); 13C NMR (CDCl3) ꢄ 11.74 (SCH3), 13.88 (C-10), 20.58,
20.65, 20.77 (3 ꢇ OCOCH3), 22.36, 25.01, 30.43, 31.47 (C-6, C-7, C-8, C-9),
67.20 (C-2), 69.53 (C-4), 72.44 (C-3), 77.33 (C-5), 83.51 (C-1), 169.67, 170.08,
170.48 (3 ꢇ OCOCH3).
Anal. Calcd C17H28O7S (376.46): C, 54.23; H, 7.49; S, 8.51. Found: C, 54.34;
H, 7.59; S, 8.65.
Methyl 2,3,4-tri-O-acetyl-10-methoxycarbonyl-6,7,8,9,10-pentadeoxy-1-
thio-ꢀ-L-galacto-decopyranoside (18). (5.7 g, 87%, TLC, solvent H, Rf 0.53),
1
colorless crystals: mp 52–55 °C; [ꢂ]D22 ꢅ14.5° (c 1.0, chloroform); H NMR
(CDCl3) ꢄ 1.26–1.71 (3m, 8H, H-6, H-6ꢁ, H-7,H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.95,
2.04, 2.13, 2.16 (4s, 12H, 3 ꢇ OCOCH3, SCH3), 2.26 (t, 2H, H-10, H-10ꢁ), 3.58
(m, 1H, H-5), 3.63 (s, 3H, CO2CH3), 4.32 (d, 1H, J1,2 ꢃ 9.7 Hz, H-1), 5.01 (dd, 1H,
J
3,4 ꢃ 3.9 Hz, H-3), 5.19 (t, 1H, J2,3 ꢃ 9.9 Hz, H-2), 5.29 (dd, 1H, J4,5 ꢃ 0.7 Hz,
H-4); 13C NMR (CDCl3) ꢄ 11.67 (SCH3), 20.52, 20.59, 20.71 (3 ꢇ OCOCH3),
24.57, 25.01, 28.72, 30.27, 33.79 (C-6, C-7, C-8, C-9, C-10), 51.35 (CO2CH3),
67.09 (C-2), 69.49 (C-4), 72.34 (C-3), 77.14 (C-5), 83.47 (C-1), 169.64, 170.03,
170.45 (3 ꢇ OCOCH3), 173.93 (CO2CH3).
Anal. Calcd for C19H30O9S (434.50): C, 52.52; H, 6.96; S, 7.38. Found:
C, 52.65; H, 6.93; S, 7.17.
Deacetylation of 17 and 18. Methanolic 0.5 M sodium methoxide (6 mL) was
added to a stirred solution of 17 (3.4g, 9 mmol) or 18 (3.9 g, 9 mmol) in dry
methanol (60 mL) at ambient temperature. When the reaction was complete fol-

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626
OTT ET AL.
lowed by TLC, the mixture was passed through a layer of Dowex 50 (Hꢈ form),
and the filtrate was concentrated.
Methyl 6,7,8,9,10-pentadeoxy-1-thio-ꢀ-L-galacto-decopyranoside (19).
(1.8 g, 80%, TLC, solvent J, Rf 0.48), colorless crystals: mp 93–94°C (from ethyl
acetate); [ꢂ]D22 ꢈ4.5° (c 1.0, chloroform); 1H NMR (CD3OD) ꢄ 0.90 (t, 3H, H-10,
H-10ꢁ, H-10ꢋ), 1.35, 1.50, 1.75 (3m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-
9ꢁ), 2.30 (s, 3H, SCH3), 3.42 (m, 1H, H-5), 3.48 (dd, 1H, J3,4 ꢃ 3.2 Hz, H-3), 3.55
(t, 1H, H-2), 3.72 (dd, 1H, J4,5 ꢃ 0.8 Hz, H-4), 4.19 (d, 1H, J1,2 ꢃ 9.1 Hz, H-1);
13C NMR (CD3OD) ꢄ 15.32 (SCH3), 17.36 (C-10), 26.61, 29.56, 34.79, 35.89 (C-
6, C-7, C-8, C-9), 74.11 (C-2), 75.15 (C-4), 79.49 (C-3), 83.11 (C-5), 90.76 (C-1).
Anal. Calcd C11H22O4S (250.35): C, 52.77; H, 8.85; S, 12.80. Found: C,
52.47; H, 8.66; S, 12.71.
Methyl 10-methoxycarbonyl-6,7,8,9,10-pentadeoxy-1-thio-ꢀ-L-galacto-
decopyranoside (20). (2.5g, 89%, TLC, solvent K, Rf 0.42), the resulting syrup
crystallized after a few days in the refrigerator: mp 73–75 °C; [ꢂ]D23–6.4° (c 1.0,
chloroform); 1H NMR (CD3OD) ꢄ 1.31–1.84 (m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8,
H-8ꢁ, H-9, H-9ꢁ), 2.21 (s, 3H, SCH3), 2.36 (t, 2H, H-10, H-10ꢁ), 3.46 (m, 1H, H-
5), 3.49 (dd, 1H, J3,4 ꢃ 3.3 Hz, H-3), 3.56 (t, 1H, J2,3 ꢃ 9.3 Hz, H-2), 3.68 (s, 3H,
CO2CH3), 3.74 (dd, 1H, J4,5 ꢃ 0.8 Hz, H-4), (d, 1H, J1,2 ꢃ 9.3 Hz, H-1); 13C NMR
(CD3OD) ꢄ 12.20 (SCH3), 25.78, 26.38, 29.91, 31.53, 34.59 (C-6, C-7, C-8, C-9,
C-10), 51.85 (CO2CH3), 71.01 (C-2), 72.09 (C-4), 76.39 (C-3), 79.89 (C-5), 87.67
(C-1), 175.96 (CO2CH3).
Anal. Calcd for C13H24O6S (308.39): C, 50.63; H, 7.84; S 10.40. Found: C,
50.64; H, 7.74; S, 10.25.
Benzylation of 19 and 20. Sodium hydride (600 mg, 75% of sodium hy-
dride by weight, 18.5 mmol) was added to a stirred solution of 19 (1.5 g, 6 mmol)
or 20 (1.85 g, 6 mmol ) and benzyl bromide (2.6 mL, 22 mmol) in dry N,N- dimethyl-
formamide (20 mL) under an argon atmosphere at ꢅ60 °C. After 15 min at that tem-
perature, the reaction mixture was allowed to warm up to ambient temperature and
stirring was continued for a further 4 h followed by TLC. Methanol (3 mL) was then
added and after 15 min, the mixture was diluted with chloroform (70 ml) and hep-
tane (140 mL). The organic layer was washed successively with ice-water
(2 ꢇ 70 mL), cold aq 1 M hydrochloric acid (2 ꢇ 70 mL), ice-water (70 mL), cold
sat aq NaHCO3 (2 ꢇ 70 mL), ice-water (2 ꢇ 70 mL), dried and concentrated. The
crude products were purified by column chromatography (eluent ethyl acetate gra-
dient 0% → 10% in heptane).
Methyl 2,3,4-tri-O-benzyl-6,7,8,9,10-pentadeoxy-1-thio-ꢀ-L-galacto-de-
copyranoside (21). (1.5 g, 47 %, TLC, solvent E, Rf 0.58), colorless syrup:[ꢂ]D23
ꢅ6.8° (c 1.0, chloroform); 1H NMR (CDCl3) ꢄ 0.86 (t, 3H, H-10, H-10ꢁ, H-10ꢋ),
1.24, 1.50, 1.80 (3m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.22 (s, 3H,
SCH3), 3.25 (m, 1H, H-5), 3.57 (dd, 1H, J3,4 ꢃ 2.8 Hz, H-3), 3.70 (d, 1H, J4,5 ꢀ0

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SPACER-MODIFIED L-FUCOSE ANALOGUES
627
Hz, H-4), 3.86 (t, 1H, J2,3 ꢃ 9.4 Hz, H-2), 4.31 (d, 1H, J1,2 ꢃ 9.4 Hz, H-1),
4.66–5.15 (m, 6H, CH2C6H5), 7.15–7.42 (m, 15H, CH2C6H5); 13C NMR (CDCl3)
ꢄ 12.92 (SCH3), 14.03 (C-10), 22.54, 25.56, 31.14, 31.75 (C-6, C-7, C-8, C-9),
72.92, 74.38, 75.66 (3 ꢇ CH2C6H5), 75.31 (C-4), 78.43 (C-2), 78.90 (C-5), 84.78
(C-3), 85.68 (C-1), 127.50, 127.55, 127.65, 127.70, 128.17, 128.20, 129.43,
138.33, 138.45, 138.75 (CH2C6H5, 4 ꢇ 2 signals are isochronic).
Anal. Calcd C32H40O4S (520.72): C, 73.81; H, 7.74; S, 6.15. Found: C, 73.85;
H, 7.86; S, 5.98.
Methyl 2,3,4-tri-O-benzyl-10-methoxycarbonyl-6,7,8,9,10-pentadeoxy-
1-thio-ꢀ-L-galacto-decopyranoside (22). (1.4 g, 40%, TLC, solvent D, Rf 0.54),
colorless crystals: mp 40–43 °C (from ethyl acetate - heptane),[ꢂ]D23 ꢅ0.6° (c 1.0,
chloroform); 1H NMR (CDCl3) ꢄ 1.11–1.65 (3m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8,
H-8ꢁ, H-9, H-9ꢁ), 2.23 (s, 3H, SCH3), 2.30 (t, 2H, H-10, H-10ꢁ), 3.25 (m, 1H,
H-5), 3.58 (dd, 1H, J3,4 ꢃ 2.9 Hz, H-3), 3.67 (s, 3H, CO2CH3), 3.70 (d, 1H, J4,5 ꢀ0
Hz, H-4), 3.87 (t, 1H, J2,3 ꢃ 9.3 Hz, H-2), 4.32 (d, 1H, J1,2 ꢃ 9.3 Hz, H-1), 4.70,
5.02 (2d, 2H, J ꢃ 12.0 Hz, CH2C6H5), 4.79 (s, 2H, CH2C6H5), 4.84, 4.90 (2d, 2H,
J ꢃ 10.4 Hz, CH2C6H5), 7.26–7.44 (m, 15H, 3 ꢇ CH2C6H5); 13C NMR (CDCl3) ꢄ
13.02 (SCH3), 24.81, 25.54, 29.02, 31.0, 34,03 (C-6, C-7, C-8, C-9, C-10), 51.52
(CO2CH3), 72.94, 74.42 (2 ꢇ CH2C6H5), 75.30 (C-4), 75.71 (CH2C6H5), 78.40
(C-2), 78.72 (C-5), 84.73 (C-3), 85.71 (C-1), 127.52, 127.51, 127.60, 127.69,
128.18, 128.24, 129.47, 138.36, 138.49, 138.74 (CH2C6H5, 4 ꢇ 2 signals are
isochronic), 174.92 (CO2CH3).
Anal. Calcd for C34H42O6S (578.77): C, 70.56; H, 7.31; S 5.54. Found:
C, 70.24; H, 7.14; S, 5.58.
Methyl 10-methoxycarbonyl-6,7,8,9,10-pentadeoxy-1-thio-2,3,4-tris-O-
trimethylsilyl-ꢀ-L-galacto-decopyranoside (23). Trimethylsilyl chloride (0.76
mL, 6.0 mmol) was added dropwise to a solution of 20 (308 mg, 1.0 mmol) in dry
pyridine (4.5 ml) at ambient temperature. After stirring for two hours under an ar-
gon atmosphere followed by TLC (solvent A, Rf 0.34), dry ether (30 mL) was
added and the precipitated pyridinium salts were separated by filtration. The fil-
trate was concentrated and then coconcentrated with toluene (3 ꢇ 50 mL). The
residue was again dissolved in dry ether (30 mL), the solution filtered, concen-
trated and coconcentrated with toluene. The syrup obtained was then purified by
HPLC (eluent solvent A) to provide 23 (357 mg, 68%) as a colorless syrup: [ꢂ]D23
1
ꢈ12.3° (c 1.0, CHCl3); H NMR (CDCl3): ꢄ 0.11, 0.15, 0.16 [3s, 27H, 3 ꢇ
Si(CH3)3], 1.24–1.75 (m, 8H, H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 2.14 (s,
3H, SCH3), 2.29 (t, 2H, H-10, H-10ꢁ), 3.28 (m, 1H, H-5), 3.39 (dd, 1H, J3,4 ꢃ 2.7
Hz, H-3), 3,62 (d, 1H, J4,5 ꢀ0.0 Hz, H-4), 3.64 (s, 3H, CO2CH3), 3.74 (t, 1H, J2,3
ꢃ 9.2 Hz, H-2), 4.19 (d, 1H, J1,2 ꢃ 9.2 Hz, H-1); 13C NMR (CDCl3): ꢄ 0.43, 0.80,
1.08 [3 ꢇ Si(CH3)3], 13.14 (SCH3), 24.89, 25.42, 29.08, 31.02 (C-6, C-7, C-8, C-
9), 34.00 (C-10), 51.42 (CO2CH3), 71.05 (C-2), 74.40 (C-4), 77.15 (C-3), 78.91
(C-5), 87.26 (C-1), 175.14 (CO2CH3).

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OTT ET AL.
Anal. Calcd for C22H48O6SSi3 (524.93): C, 50.33; H, 9.55; S, 6.11. Found:
C, 50.21; H, 9.49; S 6.23.
Benzyl 2,3,4,6-tetra-O-benzyl-ꢀ-D-galactopyranosyl-(1→4)-[2,3,4-tri-O-
benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-(1→3)]-2,6-di-O-
benzyl-ꢀ-D-glucopyranoside (26). Promotion by IDCP: Powdered molecular
sieves (4Å, 1.0 g) were added to a solution of benzyl 2,3,4,6-tetra-O-benzyl-ꢀ-D-
galactopyranosyl-(1→4)-2,6-di-O-benzyl-ꢀ-D-glucopyranoside (24, 889 mg, 0.91
mmol) and glycosyl donor 21 (547 mg, 1.05 mmol) in dry diethyl ether (15 mL)
and dry dichloromethane (3 mL), and the mixture was stirred under an argon at-
mosphere for one hour at room temperature. After cooling to 0°C, iodonium di-
sym-collidine perchlorate (IDCP, 939 mg, 2.00 mmol) was added. After 15 min at
that temperature, the reaction mixture was stirred for a further 3.5 h at ambient tem-
perature (TLC, solvent F, Rf 0.47). Chloroform (250 mL) was then added and the
solids were filtered off. The filtrate was washed with cold aq 10% sodium thiosul-
fate (2 ꢇ 100 mL), ice-water (2 ꢇ 75 mL), cold aq 1M hydrochloric acid (2 ꢇ 50
mL), ice-water (2 ꢇ 75 mL), dried and concentrated. The crude product was puri-
fied by MPLC (eluent ethyl acetate gradient 0% → 14% in heptane) to furnish the
trisaccharide 26 (439 mg, 33%) as a colorless syrup.
Promotion by DMTST: To a solution of acceptor 24 (227 mg, 0.23 mmol) and
donor 21 (84 mg, 0.16 mmol) in dry toluene (5 mL) were added powdered molec-
ular sieves (4Å, 400 mg), and the mixture was stirred under argon for one hour at
room temperature. After cooling to 0°C, dimethyl(methylthio)sulfonium triflate
(DMTST, 102 mg, 0.4 mmol) was added and stirring was continued for a further
20 h at that temperature (TLC, solvent F, Rf 0.47). Triethylamine (0.1 ml),
methanol (0.1 ml), and chloroform (100 mL) were then added and the mixture was
filtered. The filtrate was washed with ice-water (2 ꢇ 50 mL), sat aq NaHCO3
(2 ꢇ 50 mL), ice-water (2 ꢇ 50 mL), dried, and concentrated. The crude product
was purified by MPLC (eluent ethyl acetate gradient 0% → 14% in heptane) to
yield 26 (89 mg, 38%) as a colorless syrup: [ꢂ]D24 ꢅ55.5° (c 1.0, chloroform); 1H
NMR (CDCl3) ꢄ 0.94 (t, 3H, J ꢃ 6.4 Hz, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.30–1.71 (m,
8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 3.38–4.35 (3m, 16H, Gal:
H-2, H-3, H-4, H-5, H-6, H-6ꢁ, Glc: H-2, H-3, H-4, H-5, H-6, H-6ꢁ, Fuc: H-2,
H-3, H-4, H-5), 4.38–5.16 (m, 20H, 10 ꢇ CH2C6H5), 4.58, 4.59 (2d, 2H, J1,2 ꢃ 7.3
Hz and 7.6 Hz, Gal: H-1, Glc: H-1), 5.81 (d, 1H, J1,2 ꢃ 3.5 Hz, Fuc: H-1),
7.20–7.57 (m, 50H, 10 ꢇ CH2C6H5); 13C NMR (CDCl3) ꢄ 14.28 (Fuc: C-10),
22.61, 25.17, 30.90, 32.79 (Fuc: C-6, C-7, C-8, C-9), 67.86, 67.95 (Gal: C-6, Glc:
C-6), 69.88, 72.58, 73.87, 74.16, 74.85, 75.68, 77.88, 79.46, 80.04, 82.56, 83.02
(Fuc, Gal, Glc: C-2, C-3, C-4, C-5; two signals are isochronic), 70.79, 72.38, 72.68,
73.02, 73.13, 73.37, 75.04, 75.30, 75.42 (10 ꢇ CH2C6H5, two signals are
isochronic), 96.93 (Fuc: C-1), 102.55, 102.60 (Gal: C-1, Glc: C-1), 126.53–139.22
(10 ꢇ CH2C6H5).
Anal. Calcd for C92H100O15 (1445.78): C, 76.43; H, 6.97. Found: C, 76.27;
H, 6.85.

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SPACER-MODIFIED L-FUCOSE ANALOGUES
629
Benzyl 2,6-di-O-benzyl-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→
4)-[2,3,4-tri-O-benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→3)]-2,6-di-O-benzyl-ꢀ-D-glucopyranoside (27). Powdered molecular
sieves (4Å, 1.5 g) were added to a solution of benzyl 2,6-di-O-benzyl-3,4-O-iso-
propylidene-ꢀ-D-galactopyranosyl-(1→4)-2,6-di-O-benzyl-ꢀ-D-glucopyranoside
(25, 0.49 g, 0.6 mmol) and glycosyl donor 21 (0.31 g, 0.6 mmol) in dry toluene (7
mL) and the mixture was stirred under argon for one hour at room temperature.
Dimethyl(methylthio)sulfonium triflate (DMTST, 0.46 g, 1.78 mmol) was added
after cooling to 0°C and stirring was continued for further 10 h at 0 °C (TLC, sol-
vent G, Rf 0.51). The reaction mixture was then filtered, diluted with heptane (140
mL) and chloroform (70 mL), and the organic layer washed with water (2 ꢇ 50
mL), sat aq NaHCO3 (3 ꢇ 50 mL), water (2 ꢇ 50 mL), dried, and concentrated.
The residue was purified by column chromatography (eluent solvent B) giving the
starting material 25 (320 mg) and the trisaccharide 27 (230 mg, 30%, or 84% based
22
D ꢅ
on recovered acceptor 25) as a light-yellow syrup:[ꢂ]
33.1° (c 1.0, chloroform);
1H NMR (CDCl3) ꢄ 0.91 (t, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.22–1.42 (3m, 8H,
Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.50, 1.54 [2s, 6H, C(CH3)2],
3.26 (dd, 1H, Gal: H-2), 3.32–4.17 (3m, 13H, Glc, Fuc: H-2, H-3, H-4, H-5; Gal:
H-3, H-4, H-5, H-6, H-6ꢁ), 4.38–5.17 (m, 18H, 8 ꢇ CH2C6H5 and Glc: H-6, H-6ꢁ),
4.54 (d, 1H, J1,2 ꢃ 7.8 Hz, Gal: H-1), 4.63 (d, 1H, J1,2 ꢃ 7.2 Hz, Glc: H-1), 5.78
(d, 1H, J1,2 ꢃ 3.2 Hz, Fuc: H-1), 7.24–7.52 (m, 40H, 8 ꢇ CH2C6H5); 13C NMR
(CDCl3) ꢄ 14.26 (Fuc: C-10), 22.59, 25.66, 31.52, 32.63 (Fuc: C-6, C-7, C-8, C-9),
26.35, 28.23 [C(CH3)2], 67.82 (Gal: C-6), 68.93 (Glc: C-6), 69.84, 71.67, 72.74,
73.61, 74.48, 75.40, 76.12, 77.34, 79.62, 79.75, 81.84, 83.26 (Glc, Gal, Fuc: C-2,
C-3, C-4, C-5), 70.93, 72.90, 73.26, 73.32, 73.47, 73.80, 74.85 (8 ꢇ CH2C6H5, two
signals are isochronic), 96.72 (Fuc: C-1), 102.15 (Gal: C-1), 102.57 (Glc: C-1),
109.60 [C(CH3)2], 126.51–139.30 (8 ꢇ CH2C6H5).
Anal. Calcd C81H92O15 (1305.61): C, 74.52; H, 7.10. Found: C, 74.25; H,
7.08.
Benzyl 2,6-di-O-benzyl-ꢀ-D-galactopyranosyl-(1→4)-[2,3,4-tri-O-ben-
zyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-(1→3)]-2,6-di-O-ben-
zyl-ꢀ-D-glucopyranoside (28). A solution of 27 (261 mg, 0.2 mmol) in aq 80%
acetic acid (35 mL) was heated overnight at 50°C. When the reaction was complete
(TLC, solvent H, Rf 0,53), the solution was diluted with toluene (70 mL) and con-
centrated. Traces of acetic acid were removed by repeated coconcentration with
toluene (3 ꢇ 30 mL). The residue was purified by column chromatography (eluent
solvent E) to provide 28 (152 mg, 60%) as a syrup: [ꢂ]D23 ꢅ41,5° (c 1.0, chloro-
form); 1H NMR (CDCl3) ꢄ 0.81 (t, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.16–1.62, (3m,
8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 3.28–5.04 (4m, 32H, 8 ꢇ
CH2C6H5; Glc, Gal, Fuc: H-2, H-3, H-4, H-5; Glc, Gal: H-6, H-6ꢁ), 4.47 (d, 1H,
J
1,2 ꢃ 8.5 Hz, Gal: H-1), 4.49 (d, 1H, J1,2 ꢃ 7.8 Hz, Glc: H-1), 5.74 (d, 1H, J1,2 ꢃ
3.3 Hz, Fuc: H-1), 7.04–7.40 (m, 40H, 8 ꢇ CH2C6H5); 13C NMR (CDCl3) ꢄ 14.25
(Fuc: C-10), 22.73, 25.19, 29.73, 32.75 (Fuc: C-6, C-7, C-8, C-9), 67.90 (Gal: C-

ORDER
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630
OTT ET AL.
6), 68.15 (Glc: C-6), 69.95, 70.79, 72.44, 72.87, 74.87, 75.17, 75.34, 75.95, 77.11,
79.77, 80.45, 82.98 (Glc, Gal, Fuc: C-2, C-3, C-4, C-5), 70.87, 72.69, 72.96, 73.18,
73.29, 73.37, 74.96, 75.07 (8 ꢇ CH2C6H5), 97.06 (Fuc: C-1), 102.45 (Gal: C-1),
102.65 (Glc: C-1), 126.41–139.23 (8 ꢇ CH2C6H5).
Anal. Calcd C78H88O15 (1265.54): C, 74.03; H, 7.01. Found: C, 74.18; H,
7.25.
ꢀ-D-Galactopyranosyl-(1→4)-[6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-de-
copyranosyl-(1→3)-ꢂ,ꢀ-D-glucopyranose (29). To a solution of 26 (145 mg,
0.1 mmol) or 28 (127 mg, 0.1 mmol) in ethanol (15 mL) and acetic acid (2 mL) pal-
ladium-on-charcoal (70 mg) was added. The suspension was stirred under an at-
mosphere of hydrogen for 24 h at room temperature. When the reaction was com-
plete (TLC, solvent P, Rf 0.20), the mixture was filtered over Celite, successively
eluted with ethanol, and the combined filtrates were concentrated. The residue was
purified by column chromatography (eluent solvent O) or RP-HPLC (eluent water
gradient 0% → 67% in methanol) to provide 29 (49 mg, 90%) as an amorphous col-
orless solid: 13C NMR (D2O) ꢄ 14.20 (Fuc: C-10), 22.25, 25.28, 30.66, 32.37 (Fuc:
C-6, C-7, C-8, C-9), 60.63, 60.65 (Glc: C-6ꢂ,ꢀ), 62.19 (Gal: C-6), 69.19, 69.94,
71.30, 71.74, 71.74, 72.09, 73.40, 72.79, 73.98, 74.18, 75.83, 76.16, 76.32, 76.62
(Gal, Glc, Fuc: C-2, C-3, C-4, C-5), 92.91 (Glc: C-1ꢀ), 96.57 (Glc: C-1ꢂ), 98.10,
98.34 (Fuc: C-1), 103.00 (Gal: C-1).
Anal. Calcd C22H40O15 (544.55): C, 48.52; H, 7.40. Found: C, 48.22; H, 7.28.
2,3,4-Tri-O-benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-6-O-benzoyl-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→4)-
2,3;4,6-di-O-isopropylidene-D-glucose dimethyl acetal (31). A suspension of
6-O-benzoyl-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→4)-2,3;4,6-di-O-
isopropylidene-D-glucose dimethyl acetal (30, 4.57 g, 7.5 mmol)18–20 and molecu-
lar sieves (4Å, 10 g) in dry ethyl ether (20 mL) and dry dichloromethane (4 mL)
was stirred for one hour under an atmosphere of argon at ambient temperature. Af-
ter cooling to 4°C, iodonium di-sym-collidine perchlorate (IDCP, 3.01 g, 6.4
mmol) and, after an additional 15 min, the glycosyl donor 21 (2.01 g, 3.86 mmol)
were added. The mixture was then allowed to react for 90 min at room temperature
(TLC, solvent G, Rf 0.42). The resulting suspension was diluted with chloroform
(250 mL) and filtered through a layer of Celite. The filtrate was washed with cold
aq 10% sodium thiosulfate (2 ꢇ 100 mL), ice-water (2 ꢇ 100 mL), dried and con-
centrated. The crude product was purified by MPLC (eluent ethyl acetate gradient
0% → 25% in heptane) to provide 31 (1.92 g, 46%,) as a colorless foam: [ꢂ]D23
ꢅ69.5° (c 1.0, CHCl3); 1H NMR (CDCl3) ꢄ 0.86 (t, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ),
1.20–1.63 (m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.27, 1.33,
1.37, 1.43, 1.50 [5s, 18H, 3 ꢇ C(CH3)2], 3.35, 3.37 [2s, 6H, C(OCH3)2], 3.76 (m,
2H, Gal: H-2, Fuc: H-4), 3.84 (m, 1H, Fuc: H-5), 3.94 (dd, 1H, J5,6 ꢃ 6.4 Hz, J6,6ꢁ
ꢃ 8.3 Hz, Glc: H-6), 3.99 (dd, 1H, J4,5 ꢃ 5.4 Hz, Glc: H-4), 4.03–4.15 (m, 5H, Fuc:
H-2, H-3, Gal: H-4, H-5, Glc: H-6ꢁ), 4.17 (dd, 1H, J3,4 ꢃ 2.0 Hz, Glc: H-3), 4.20

ORDER
REPRINTS
SPACER-MODIFIED L-FUCOSE ANALOGUES
631
(t, 1H, J2,3 ꢃ J3,4 ꢃ 5.7 Hz, Gal: H-3), 4.27 (m, 1H, Glc: H-5), 4.45 (d, 1H, J1,2
ꢃ 6.0 Hz, Glc: H-1), 4.48 (dd, 1H, J2,3 ꢃ 7.5 Hz, Glc: H-2), 4.56 (d, 2H, J5,6 ꢃ 6.0
Hz, Gal: H-6, H-6ꢁ), 4.76 (s, 2H, CH2C6H5), 4.75 (d, 1H, J1,2 ꢃ 7.6 Hz, Gal: H-1),
4.64, 4.78, 4.91, 4.99 (4d, 4H, J ꢃ 11.6 Hz, 2 ꢇ CH2C6H5), 5.63 (d, 1H, J1,2 ꢃ 3.2
Hz, Fuc: H-1), 7.29–8.10 (m, 20 H, CH2C6H5); 13C NMR (CDCl3) ꢄ 14.10 (Fuc:
C-10), 22.57, 25.32 (Fuc: C-8, C-9), 25.39, 26.42, 26.72, 26.94, 27.09, 27.84 [Gal,
Glc: 3 ꢇ C(CH3)2], 30.86, 32.22 (Fuc: C-6, C-7), 53.15, 55.95 [Glc: C(OCH3)2],
63.82 (Gal: C-6), 65.54 (Glc: C-6), 70.94 (Fuc: C-2, C-5, two signals are
isochronic), 72.74, 73.26, 74.50 (3 ꢇ CH2C6H5), 73.79 (Glc: C-3), 74.68 (Glc:
C-4), 74.97 (Glc: C-2), 75.13 (Fuc: C-4), 76.56 (Gal: C-2), 76.80 (Fuc: C-3), 77.26
(Glc: C-5), 77.60 (Gal: C-5), 79.48 (Gal: C-4), 80.09 (Gal: C-3), 94.83 (Fuc: C-1),
101.26 (Gal: C-1), 105.33 (Glc: C-1), 108.72, 109.78, 110.35 [3 ꢇ C(CH3)2],
127.29–139.38 (3 ꢇ CH2C6H5, OCOC6H5), 166.32 (OCOC6H5); FABꢈ mass
spectrum matrix nitrobenzyl alcohol: m/z 1084 [C61H80O17, 9%], 779 [M-Glcꢈ,
21%], 335 [100%].
Anal. Calcd for C61H80O17 (1085.28): C, 67.50; H, 7.42. Found: C, 67.29;
H, 7.41.
The proposed ꢀ-Fuc isomer (180 mg, 5%, in an 1 : 1 mixture together with
31, TLC, solvent G, Rf 0.44); gave additional signals in the anomeric region: 13
NMR (CDCl3) ꢄ 102.56 (Fuc: C-1), 103.05 (Gal: C-1), 105.25 (Glc: C-1).
C
2,3,4-Tri-O-benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→4)-2,3;4,6-di-O-iso-
propylidene-D-glucose dimethyl acetal (32). A methanolic sodium methoxide
solution (0.4 M, 4 mL) was added to a solution of 31 (1.63 g, 1.5 mmol) in dry
methanol (40 ml) and the mixture was stirred under an atmosphere of argon
overnight at ambient temperature (TLC, solvent H, Rf 0.44). The solution was then
passed through a layer of DOWEX 50 ꢇ 4 [Hꢈ] and concentrated. The residue was
purified by MPLC (eluent ethyl acetate gradient 30% → 50% in heptane) to pro-
vide 32 (1.24 g, 84%,) as a colorless syrup: [ꢂ]D23 ꢅ39.7° (c 1.0, chloroform); 1H
NMR (CDCl3) ꢄ 0.85 (t, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.18–1.63 (m, 8H, Fuc:
H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.30, 1.36, 1.38, 1.45 [4s, 18H,
C(CH3)2, 2 signals are isochronic], 3.48 [s, 6H, C(OCH3)2], 3.61 (m, 1H, Fuc: H-
4), 3.66 (dd, 1H, J4,5 ꢃ 1.5 Hz, Gal: H-4), 3.70 (dd, 1H, J2,3 ꢃ 6.2 Hz, Gal: H-2),
3.74–3.85 (m, 3H, Fuc: H-5, Gal: H-6, H-6ꢁ), 3.86 (dd, 1H, J5,6 ꢃ 6.0 Hz, J6,6ꢁ
ꢃ 8.1 Hz, Glc: H-6), 3.94 (dd, 1H, J4,5 ꢃ 5.6 Hz, Glc: H-4), 3.96–4.11 (m, 5H, Fuc:
H-2, H-3, Gal: H-5, Glc: H-3, H-6ꢁ), 4.17 (t, 1H, J3,4 ꢃ 6.0 Hz, Gal: H-3), 4.24 (m,
1H, Glc: H-5), 4.36 (d, 1H, J1,2 ꢃ 6.8 Hz, Glc: H-1), 4.54 (dd, 1H, J1,2 ꢃ 8.0 Hz,
Gal: H-1), 4.61 (d, 1H, J2,3 ꢃ 8.0 Hz, Glc: H-2), 4.63, 5.00 (2d, 2H, J ꢃ 11.7 Hz,
CH2C6H5), 4.76 (s, 2H, CH2C6H5), 4.85 (d, 2H, J ꢃ 11.9 Hz, CH2C6H5), 5.60 (d,
1H, J1,2 ꢃ 3.6 Hz, Fuc: H-1), 7.29–7.46 (m, 15 H, CH2C6H5); 13C NMR (CDCl3)
ꢄ 14.11 (Fuc: C-10), 22.57, 25.27, (Fuc: C-8, C-9), 25.35, 26.45, 26.47, 27.03,
27.05, 27.90 [3 ꢇ C(CH3)2], 30.72, 32.27 (Fuc: C-6, C-7), 53.93, 57.61
[C(OCH3)2], 62.50 (Gal: C-6), 65.23 (Glc: C-6), 72.83, 73.19, 74.63 (3

ORDER
REPRINTS
632
OTT ET AL.
ꢇ CH2C6H5), 70.93, 73.97, 74.67, 74.72, 75.79, 76.68, 76.37, 76.75, 77.19, 77.87,
79.42, 80.70 (Glc, Gal, Fuc: C-2, C-3, C-4, C-5), 94.86 (Fuc: C-1), 101.78 (Gal: C-
1), 107.55 (Glc: C-1), 108.80, 109.56, 110.48 [3 ꢇ C(CH3)2], 127.38, 127.45,
127.75, 128.13, 128.32, 128.38, 138.92, 139.01, 139.27 (3 ꢇ CH2C6H5, 9 signals
are isochronic); FABꢈ mass spectrum, matrix nitrobenzylalcohol: m/z 981
[C54H76Oꢈ16, 20%], 675 [M-Glcꢈ, 14%], 272 [100%], 241 [100%].
Anal. Calcd for C54H76O16 (981.18): C, 66.10; H, 7.80. Found: C, 65.85;
H, 7.92.
10-Methoxycarbonyl-2,3,4-tri-O-trimethylsilyl-6,7,8,9,10-pentadeoxy-ꢂ-
L-galacto-decopyranosyl-(1→2)-6-O-benzoyl-3,4-O-isopropylidene-ꢀ-D-galac-
topyranosyl-(1→4)-2,3;4,6-di-O-isopropylidene-D-glucose dimethyl acetal
(33). The glycosyl acceptor 30 (613 mg, 1.0 mmol) and molecular sieves (4 Å,
2.0 g) were added to a solution of freshly prepared glycosyl donor 23 (630 mg, 1.2
mmol) in dry diethyl ether (30 mL) and dry dichloromethane (6 mL). After stirring
under an atmosphere of argon for 30 min at 4 °C, iodonium di-sym-collidine per-
chlorate (IDCP, 761 mg, 1.6 mmol) was added and stirring was continued for one
hour at room temperature (TLC, solvent H, Rf 0.44). The reaction mixture was then
diluted with chloroform (100 mL) and passed through a layer of Celite. The filtrate
was washed with cold aq 10% sodium thiosulfate (2 ꢇ 30 mL), ice-water (2 ꢇ 30
mL), dried and concentrated. The residue was purified by column chromatography
(eluent solvent D) to give 33 (850 mg, 78%,) as a syrup: [ꢂ]D23 ꢅ65.3° (c 1.0, chlo-
roform); 1H NMR (CDCl3) ꢄ 0.03, 0.09, 0.11 [3s, 27H, 3 ꢇ Si(CH3)3], 1.24–1.65
(m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.25, 1.27, 1.34, 1.35,
1.40, 1.43 [6s, 18H, 3 ꢇ C(CH3)2], 2.26 (t, 2H, Fuc: H-10, H-10ꢁ), 3.30, 3.33 [2s,
6H, C(OCH3)2], 3.64 (s, 3H, CO2CH3), 3.65 (d, 1H, Fuc: H-4), 3.70 (dd, 1H, J2,3
ꢃ 5,6 Hz, Gal: H-2), 3.77 (dd, 1H, J3,4 ꢃ 2.7 Hz, Fuc: H-3), 3.79 (m, 1H, Fuc:
H-5), 3.87 (dd, 1H, J2,3 ꢃ 9.5 Hz, Fuc: H-2), 3.96 (dd, 1H, J3,4 ꢃ 5.9 Hz, J4,5 ꢃ 1.9
Hz, Gal: H-4), 3.98 (dd, 1H, J5,6 ꢃ 6.5 Hz, J6,6ꢁ ꢃ 8.5 Hz, Glc: H-6), 4.06 (m, 1H,
Gal: H-5), 4.08 (dd, 1H, J3,4 ꢃ 1.4 Hz, Glc: H-3), 4.14 (dd, 1H, J5,6ꢁ ꢃ 5.5 Hz, Glc:
H-6ꢁ), 4.21–4.24 (m, 3H, Glc: H-4, H-5, Gal: H-3), 4.34 (d, 1H, J1,2 ꢃ 5.9 Hz, Glc:
H-1), 4.49 (dd, 1H, J2,3 ꢃ 7.6 Hz, Glc: H-2), 4.53 (d, 1H, J5,6 ꢃ 5.7 Hz, Gal: H-6),
4.54 (d, 1H, J5,6ꢁ ꢃ 6.8 Hz, Gal: H-6ꢁ), 4.75 (d, 1H, J1,2 ꢃ 7.8 Hz, Gal: H-1), 5.29
(d, 1H, J1,2 ꢃ 3.7 Hz, Fuc: H-1), 7.37–8.02 (2m, 5H, OCOC6H5); 13C NMR
(CDCl3) ꢄ 0.09, 0.46, 0.70 [3 ꢇ Si(CH3)3, 3 signals are isochronic], 24.89, 25.13
(Fuc: C-7, C-8), 25.40, 26.17, 26.71, 26.92, 27.14, 27.73 [3 ꢇ C(CH3)2], 29.57,
30.8 (Fuc: C-6, C-9), 34.07 (Fuc: C-10), 51.32 (CO2CH3), 52.98, 55.82
[C(OCH3)2], 63.62 (Gal: C-6), 65.47 (Glc: C-6), 68.99 (Fuc: C-2), 70.75 (Fuc:
C-5), 70.80 (Gal: C-5), 70.92 (Fuc: C-3), 73.55 (Glc: C-5), 74.35 (Fuc: C-4), 74.43
(Gal: C-4), 74.81 (Glc: C-2), 75.82 (Gal: C-2), 77.28 (Gal, Glc: C-3, two signals
are isochronic), 79.67 (Glc: C-4), 97.41 (Fuc: C-1), 101.41 (Gal: C-1), 105.26
(Glc: C-1), 108.62, 109.77, 110.10 [C(CH3)2)], 128.35, 129.64, 129.96, 133.05
(OCOC6H5), 166.24 (OCOC6H5), 174.02 (CO2CH3).
Anal. Calcd for C51H88O19Si3 (1089.47): C, 56.22; H, 8.14. Found: C, 56.09;
H, 8.10.

ORDER
REPRINTS
SPACER-MODIFIED L-FUCOSE ANALOGUES
633
10-Methoxycarbonyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→4)-2,3;4,6-di-O-iso-
propylidene-D-glucose dimethyl acetal (34). A methanolic sodium methoxide
solution (0.5 N, 1.3 mL) was added to a solution of 33 (163 mg, 0.15 mmol) in dry
methanol (6 ml) and the mixture was stirred under an atmosphere of argon for 48
h at room temperature (TLC, solvent L, Rf 0.37). The solution was then passed
through a layer of DOWEX 50 ꢇ 4 [Hꢈ] and concentrated. The residue was puri-
fied by column chromatography (eluent solvent N) to give 34 (93 mg, 81%) as a
1
colorless syrup: [ꢂ]D23 ꢅ95.7° (c 1.0, methanol); H NMR (CD3OD) ꢄ 1.28–1.67
(m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.30, 1.32, 1.36, 1.42,
1.45 [5s, 18H, 3 ꢇ C(CH3)2, two signals are isochronic], 2.30 (t, 2H, Fuc: H-10,
H-10ꢁ), 3.45, 3.47 [2s, 6H, C(OCH3)2], 3.64 (s, 3H, CO2CH3), 3.67 (dd, 1H, J3,4
ꢃ 3.2 Hz, Fuc: H-3), 3.69 (dd, 1H, J2,3 ꢃ 6.1 Hz, Gal: H-2), 3.71 (m, 1H, Fuc: H-
5), 3.74 (dd, 1H, J2,3 ꢃ 9.0 Hz, Fuc: H-2), 3.77 (d, 1H, Fuc: H-4), 3.83 (m, 2H, Gal:
H-6, H-6ꢁ), 3.86 (dd, 1H, J4,5 ꢃ 6.6 Hz, Glc: H-4), 3.88 (m, 1H, Gal: H-5), 4.01
(dd, 1H, J5,6 ꢃ 6.3 Hz, J6,6ꢁ ꢃ 8.4 Hz, Glc: H-6), 4.13 (dd, 1H, J5,6ꢁ ꢃ 4.8 Hz, Glc:
H-6ꢁ), 4.14 (dd, 1H, J3,4 ꢃ 1.4 Hz, Glc H-3), 4.19 (dd, 1H, J4,5 ꢃ 1.7 Hz, Gal:
H-4), 4.26 (m, 1H, Glc: H-5), 4.31 (t, 1H, J3,4 ꢃ 6.1 Hz, Gal: H-3), 4.40 (d, 1H, J1,2
ꢃ 6.4 Hz, Glc: H-1), 4.53 (dd, 1H, J2,3 ꢃ 8.1 Hz, Glc: H-2), 4.59 (d, 1H, J1,2 ꢃ 8.1
Hz, Gal: H-1), 5.35 (d, 1H, J1,2 ꢃ 3.0 Hz, Fuc: H-1); 13C NMR (CD3OD) ꢄ 25.30,
26.51, 27.15, 27.31, 27.32, 28.27, [3 ꢇ C(CH3)2], 25.99, 26.45, 30.54, 31.47 (Fuc:
C-6, C-7, C-8, C-9), 34.72 (Fuc: C-10), 51.92 (CO2CH3), 55.22, 57.29
[C(OCH3)2], 62.69 (Gal: C-6), 66.85 (Glc: C-6), 70.10 (Fuc: C-5), 71.47 (Fuc:
C-2), 71.76 (Glc: C-5), 72.10 (Gal: C-2), 75.08 (Gal: C-4), 75.36 (Fuc: C-4), 76.76,
76.82 (Fuc: C-3, Glc: C-2), 76.96 (Glc: C-4), 77.89 (Glc: C-5), 78.72 (Glc: C-3),
81.42 (Gal: C-3), 97.52 (Fuc: C-1), 102.95 (Gal: C-1), 108.23 (Glc: C-1), 110.13,
110.61, 111.33 [3 ꢇ C(CH3)2], 175.89 (CO2CH3).
Anal. Calcd for C35H60O18 (768.83): C, 54.67; H, 7.87. Found: C, 54.53;
H, 7.91.
2,3,4-Tri-O-benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-4-O-ꢀ-D-galactopyranosyl-(1→4)-ꢂ/ꢀ-D-glucopyranose (35). A solution
of 32 (1.18 g, 1.2 mmol) in 30 mL aq 60% acetic acid was heated for 6 h at 60°C
(TLC, solvent L, Rf 0.19). The reaction mixture was then diluted with toluene (60
mL) and concentrated. The residue was coconcentrated with toluene (3 ꢇ 60 mL)
in order to remove traces of acetic acid. Finally, the crude product was purified by
MPLC (eluent solvent N) to yield 35 (704 mg, 72%) as a colorless syrup: Partially
interpreted 1H NMR (CD3OD) ꢄ 0.87 (m, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.16–1.59
(m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 4.44 (d, 0.4H, J1,2 ꢃ 7.7
Hz, Glc: H-1ꢀ), 4.46 (d, 1H, J1,2 ꢃ 7.0 Hz, Gal: H-1), 5.09 (d, 0.6H, J1,2 ꢃ 3.7 Hz,
Glc: H-1ꢂ), 5.72 (d, 1H, J1,2 ꢃ 3.6 Hz, Fuc: H-1), 7.24–7.46 (m, 15H, CH2C6H5);
partially interpreted 13C NMR (CD3OD) ꢄ 14.53 (Fuc: C-10), 23.50, 23.61, 26.58,
26.76, 31.98, 32.06, 33.38, 33.51 (Fuc: C-6, C-7, C-8, C-9), 61.65, 61.90 (Glc:
C-6ꢂ, C-6ꢀ), 62.48 (Gal: C-6), 73.42, 73.99, 76.00 (3 ꢇ CH2C6H5), 70.96, 71.87,
72.14, 73.00, 73.65, 75.58, 75.91, 76.39, 76.42, 76.50, 76.92, 77.27, 77.54, 77.85,

ORDER
REPRINTS
634
OTT ET AL.
77.91, 79.01, 79.34, 80.20 (Gal, Glc, Fuc: C-2, C-3, C-4, C-5), 93.69 (Glc: C-1ꢂ),
98.09 (Fuc: C-1), 98.14 (Glc: C-1ꢀ), 102.66, 102.70 (Gal: C-1), 128.57, 128.62,
128.69, 128.78, 129.20, 129.31, 129.39, 139.64, 140.07, 140.29 (3 ꢇ CH2C6H5, 8
signals are isochronic); FABꢈ mass spectrum, matrix NaCl (C43H58O15 ꢈ Na): m/z
837 [(M ꢈ Na)ꢈ, 100%].
Anal. Calcd for C43H58O15 (814.92): C, 63.37; H, 7.17. Found: C, 63.18;
H, 7.31.
6,7,8,9,10-Pentadeoxy-ꢂ-L-galacto-decopyranosyl-(1→2)-ꢀ-D-galactopy-
ranosyl-(1→4)-ꢂ/ꢀ-D-glucopyranose (36). To a solution of 35 (815 mg, 1.0
mmol) in glacial acetic acid (25 mL) palladium-on-charcoal (700 mg) was added.
The suspension was stirred under an atmosphere of hydrogen for 20 h at ambient
temperature. When the reaction was complete (TLC, solvent M, Rf 0.42), the mix-
ture was filtered over Celite and concentrated. The residue was coconcentrated
with toluene (3 ꢇ 30 mL) and purified by column chromatography (eluent solvent
1
M) to afford 36 (474 mg, 87%), as a colorless powder: Partially interpreted H
NMR (D2O) ꢄ 0.96 (m, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.34–1.72 (m, 8H, Fuc:
H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 4.57 (d, 1H, J1,2 ꢃ 7.8 Hz, Gal: H-1),
4.67 (d, 0.4H, J1,2 ꢃ 7.9 Hz, Glc: H-1ꢀ), 5.29 (d, 0.6H, J1,2 ꢃ 3.6 Hz, Glc: H-1ꢂ),
5.49, 5.51 (2d, 1H, J1,2 ꢃ 3.6 Hz, Fuc: H-1); partially interpreted 13C NMR (D2O)
ꢄ 14.20 (Fuc: C-10), 22.74, 22.83, 25.57, 25.72, 30.57, 30.64, 32.22, 32.28 (Fuc:
C-6, C-7, C-8, C-9), 60.78, 60.93 (Glc: C-6), 61.92 (Gal: C-6), 69.16, 70.09, 70.49,
70.98, 71.07, 71.29, 71.79, 72.09, 72.20, 74.71, 74.84, 75.26, 75.74, 75.93, 76.04,
76.23, 77.00, 77.37 (Gal, Glc, Fuc: C-2, C-3, C-4, C-5), 92.69 (Glc: C-1ꢂ), 96.82
(Glc: C-1ꢀ), 99.32, 99.43 (Fuc: C-1), 101.35 (Gal: C-1); FABꢈ mass spectrum,
matrix NaCl (C22H40O15 ꢈ Na): m/z 567 [(M ꢈ Na)ꢈ 48%], 177 (100%).
Anal. Calcd for C22H40O15 (544.55): C, 48.52; H, 7.40. Found: C,48.28;
H, 7.16.
10-Methoxycarbonyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→ 2)-ꢀ-D-galactopyranosyl-(1→4)-ꢂ/ꢀ-D-glucopyranose (37). A stirred so-
lution of 34 (77 mg, 0.1 mmol) in aq 80% acetic acid (5.0 mL) was heated for 6 h
at 80°C. TLC analysis (eluent solvent M) indicated the formation of a unidentified
byproduct (Rf 0.52) besides the desired compound 37 (Rf 0.37). The solution was
concentrated and the residue coconcentrated with toluene (3 ꢇ 10 mL). Finally,
crude 37 was purified by preparative TLC (eluent solvent M, Rf 0.37) in which the
isolated silica gel fractions were extracted with methanol. The extracts were con-
centrated to provide 37 (28 mg, 47%) as a colorless powder: Partially interpreted
1H NMR (D2O) ꢄ 1.21–1.82 (m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-
9ꢁ), 2.43 (t, 2H, Fuc: H-10, H-10ꢁ), 3.81 (s, 3H, CO2CH3), 4.57 (d, 1H, J1,2 ꢃ 7.4
Hz, Gal: H-1), 4.66 (d, 0.53 H, J1,2 ꢃ 7.7 Hz, Glc: H-1ꢀ), 5.28 (d, 0.47 H, J1,2
ꢃ 3.4 Hz, Glc: H-1ꢂ), 5.49, 5.51 (2 d, 1H, J1,2 ꢃ 3.3 Hz, Fuc: H-1); partially in-
terpreted 13C NMR (D2O) ꢄ 25.14, 25.20, 25.66, 25.88, 29.49, 29.56, 30.61, 34.53
(Fuc: C-6, C-7, C-8, C-9, C-10), 53.02 (CO2CH3), 60.88, 61.03 (Glc: C-6), 62.04
(Gal: C-6), 69.20, 70.20, 70.55, 71.10, 71.28, 71.41, 71.78, 72.27, 74.81, 74.95,

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SPACER-MODIFIED L-FUCOSE ANALOGUES
635
75.42, 75.68, 75.92, 76.17, 76.36, 77.13, 77.40 (Gal, Glc, Fuc: C-2, C-3, C-4,
C-5), 92.79 (Glc: C-1ꢂ), 96.93 (Glc: C-1ꢀ), 99.34, 99.49 (Fuc: C-1), 101.44 (Gal:
C-1), 178.64 (CO2CH3); Fabꢈ mass spectrum, matrix nitrobenzyl alcohol/NaCl
(C24H42O17 ꢈ Na): m/z 625 [(M ꢈ Na)ꢈ, 100%].
Anal. Calcd for C24H42O17 (602.59): C, 47.84; H, 7.03. Found: C, 47.59;
H, 6.83.
ACKNOWLEDGMENTS
The authors are indebted to the Deutschen Forschungsgemeinschaft as well
as the Fonds der Chemischen Industrie for financial support.
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Received February 27, 2001
Accepted April 26, 2001

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