Synthesis of "mixed type" oligosaccharide mimetics based on a carbohydrate scaffold

Article abstract of DOI:10.1002/1099-0690(20021)2002:1<79::AID-EJOC79>3.0.CO;2-1

In multivalent glycoligands including cluster glycosides, one type of sugar epitope is normally clustered. Such molecules have been valuable tools for investigation and inhibition of cell adhesion processes. They have, for example, served as in vitro anti

Full text of DOI:10.1002/1099-0690(20021)2002:1<79::AID-EJOC79>3.0.CO;2-1

FULL PAPER
Synthesis of ‘‘Mixed Type’’ Oligosaccharide Mimetics Based on a
Carbohydrate Scaffold
Anupama Patel[a] and Thisbe K. Lindhorst*[a]
Keywords: Carbohydrates / Glycosides / Neoglycoconjugates / Oligosaccharide mimetics / Oligosaccharides
In multivalent glycoligands including cluster glycosides, one
‘‘mixed’’ glycoclusters, starting from the trifunctional galacto-
type of sugar epitope is normally clustered. Such molecules side 10 that serves as a carbohydrate scaffold, is hence pre-
have been valuable tools for investigation and inhibition of
cell adhesion processes. They have, for example, served as in
sented here. Compound 10 has three potential reactive sites,
which were addressed successively. Firstly, peptide coupling
vitro antiadhesives in mannose-specific bacterial adhesion. with the carboxy-functionalized mannoside 11 furnished the
Wild-type bacteria, however, utilize a number of different
sugar epitopes for adhesion, involving bacterial lectins of dif-
disaccharide mimetic 13, which in turn provided the trisacch-
aride mimetic 19 after peptide coupling with the amino-func-
ferent specificity. The synthesis of glycomimetics containing tionalized fucoside 17. Finally, a pentasaccharide mimetic 23
sugar derivatives from different sugar series is therefore of was obtained after thiourea-bridging with acetylated lacto-
interest, with the eventual goal of providing multivalent
glycoligands of a more complex type. The synthesis of novel
syl isothiocyanate.
Introduction
one type of glycoligand presented on a multivalent scaf-
fold.[10] The orthogonal derivatization of a carbohydrate
scaffold would allow successive attachment of different
sugar moieties, implying the synthesis of more complex oli-
gosaccharide mimetics. Orthogonally protected carbohyd-
rate derivatives were introduced as core molecules for com-
binatorial chemistry,[15Ϫ17] and carbohydrate derivatives
have only recently been derivatized to serve as scaffold mo-
lecules.[18]
Naturally occurring glycoconjugates contain complex oli-
gosaccharides of high structural diversity, which are able to
encode biological information.[1Ϫ3] This is decoded in spe-
cific molecular recognition events[4] involving saccharide
portions as the carbohydrate ligands and proteins as recep-
tors; these are called lectins and selectins, respectively.[5]
CarbohydrateϪprotein interactions mediate such important
cellular processes as signal transduction, immune response,
or adhesion of pathogens to their host cells.[6] Synthetic
glycoligands have been valuable tools with which to invest-
igate possible interference with these interactions and to ob-
tain a better understanding of their molecular details.[7,8]
They have been designed as oligosaccharide mimetics or as
structurally simplified mimetics of multivalent glycoconju-
gates,[9] as shown with, for example, neoglycopolymers or
glycodendrimers.[10,11] In all cases, the principal architecture
of these synthetic glycoligands has comprised a core molec-
ule serving as an oligovalent scaffold, carbohydrate epi-
topes, and spacers to link the sugar epitopes to the core
molecule. Recently, carbohydrate derivatives Ϫ termed ‘‘oc-
topus glycosides’’ Ϫ have been introduced[12] and used as
core molecules for the synthesis of cluster glycosides:[13] as
pentavalent ligands for shiga-like toxins, for example.[14] All
the approaches so far chosen for the synthesis of multiva-
lent glycoligands have in common that it has always been
In our group, an ABC-type building block has been syn-
thesized; it is based on mannose and bears three orthogon-
ally protected functions A, B, and C, with three free hy-
droxy groups retained in the sugar ring.[19] We have used
this building block as a core molecule for the synthesis of
oligomannoside mimetics, including a dendritic high-mo-
lecular-weight derivative, as we are especially interested in
the inhibition of mannose-specific adhesion of Escherichia
coli[20,21] by cluster mannosides and similar glycomimet-
ics.[22] In this contribution we have extended this concept to
access glycomimetics of a ‘‘mixed’’ type. The use of carbo-
hydrate moieties from different sugar series in a successive
manner should make oligosaccharide mimetics of the com-
plex and hybrid types available, similarly to the high-man-
nose-type oligosaccharides synthesized earlier.[19] Such
mixed-type glycomimetics should be of great utility for the
synthesis of lectin ligands as well as for the provision of
antiadhesives for a ‘‘multi-lectin’’-mediated adhesion scen-
ario.
[a]
Institute of Organic Chemistry, Christiana Albertina
University Kiel,
To fulfil the outlined concept, an ABC-type galactoside
(10; Scheme 2) was chosen as the core saccharide and sub-
sequently subjected to coupling reactions, firstly with a
Otto-Hahn-Platz 4, 24098 Kiel, Germany
Fax: (internat.) ϩ 49-(0)431/880-7410
E-mail: tklind@oc.uni-kiel.de
Eur. J. Org. Chem. 2002, 79Ϫ86
WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
1434Ϫ193X/02/0101Ϫ0079 $ 17.50ϩ.50/0
79

A. Patel, T. K. Lindhorst
FULL PAPER
mannoside derivative, then an -fucoside moiety, and finally obviously reacts in this case as a base rather than a nucle-
a lactose derivative, to provide a pentasaccharide mimetic in ophile, which has not been observed in the analogous case
high yield with a minimum of protecting group chemistry. in the mannose series.[19]
In order to avoid anhydro ring formation, the free hy-
droxy groups of 4 were protected prior to the nucleophilic
displacement reaction. Tosylate 4 was carefully treated at
Ϫ10 °C with acetic anhydride in pyridine, to provide the
Results and Discussion
tri-O-acetylated galactoside 6 in 97% yield. This allowed
Galactoside 10 (Scheme 2) was chosen as the central
the synthesis of the unprotected 6-azido-6-deoxy galacto-
building block, with three (potential) reactive sites. It was
side derivative 8 without problems, after deacetylation of 7.
synthesized starting from the known 2-azidoethyl β--gal-
actopyranoside 1 (Scheme 1),[23] which was subjected to Pd-
catalyzed hydrogenation in the presence of Boc2O in order
to protect the resulting free amine in situ, thus avoiding O-
Ǟ N-acetyl group migration. This procedure furnished the
Catalytic hydrogenation of 8 with palladium on charcoal
yielded the corresponding amine 9, which was then sub-
jected to a Michael-type reaction with methyl acrylate to
afford the Michael-type mono-adduct 10 in 60% overall
yield (Scheme 2). Interestingly, the bis-addition product 10a
could not be obtained even when an excess of methyl acryl-
ate[26] at elevated reaction temperatures (ca. 40 °C) was used
in the treatment of the amine 9. This may be attributable to
steric hindrance caused by the axial 4-hydroxy group in 10.
acetylated N-Boc-protected galactoside 2 in 81% yield.
[24]
´
Zemplen deprotection
afforded the tetraol 3, which was
in turn regioselectively tosylated to give 4 in 61% overall
yield. Surprisingly, when the 6-O-tosylate 4 was subjected
to a nucleophilic displacement reaction using sodium azide
in DMF, the 3,6-anhydro derivative 5 was obtained in high
Galactoside 10 represents a trifunctional carbohydrate
yield, instead of the desired azide 8. A singlet for the anom- scaffold molecule in which the three functionalities can be
eric proton and a large downfield shift of the 3-H signal successively addressed in further reactions. Thus, the sec-
1
from δ ϭ 3.45 to δ ϭ 3.92 in the H NMR spectrum of 5 ondary amino function in 10 was subjected to peptide coup-
indicated formation of the anhydro ring,[25] which may oc- ling with p-(α--mannosyloxy)methylbenzoic acid (11)[27]
1
cur through a C4 conformation of 4, in equilibrium with by using the onium salt based coupling reagent HATU.[28]
the more favored 4C1 conformation. MS data (306.1 for [M This resulted in the mixed disaccharide mimetic 12
ϩ H]ϩ) further confirmed the structure of 5. Sodium azide (Scheme 2), bearing a galactosyl and a mannosyl residue, in
Scheme 1. a) Pd/C, H2, (Boc)2O, ethyl acetate, room temp., 12 h, 81%; b) NaOMe/MeOH, 0 °C Ǟ room temp., 1 h, 96%; c) TsCl,
pyridine, 0 °C Ǟ room temp., 2 h, 64%; d) NaN3, DMF, 80 °C, 24 h, (5: 82%; 8: 0%); e) Ac2O, pyridine, Ϫ10 °C Ǟ ϩ4 °C, 12 h, 97%;
f) NaN3, DMF, 80 °C, 24 h, 72%; g) NaOMe/MeOH, 0 °C Ǟ room temp., 1 h, 98%
80
Eur. J. Org. Chem. 2002, 79Ϫ86

“Mixed Type” Oligosaccharide Mimetics
FULL PAPER
Scheme 2. a) Pd/C, H2, MeOH, room temp., 6 h; b) methyl acrylate (excess), MeOH, room temp. Ǟ 40 °C, 15 h, 60% over two steps;
c) HATU, DIPEA, DMF, room temp.Ǟ 45 °C, 12 h, 79%; d) LiOH·H2O, MeOH/H2O (2:1), 0 °C, 12 h, quant.
79% yield. Interestingly, it was observed that the galactoside NMR spectra revealed the disappearance of those signals
10 and the disaccharide mimetic 12 are prone to undergo corresponding to the protons (δ ϭ 3.63) and carbon atoms
ester hydrolysis in deuterated protic solvents. When NMR (δ ϭ 52.6) of the methyl ester. Concomitantly, additional
samples of 10 and 12 in [D]4MeOH were stored overnight signals appeared at δ ϭ 3.33 and δ ϭ 49.84, representing
at ambient temperature and then recorded, their 1H and 13
C
liberated methanol and thus indicating methyl ester hydro-
Scheme 3. a) NaN3, TBABr, DMF, 60 °C, 30 min; b) NaOMe/MeOH, 0 °C Ǟ room temp., 1 h, 70% over two steps; c) Pd/C, H2, MeOH,
room temp., 6 h, quant.; d) HATU, DIPEA, DMF, room temp. Ǟ 45 °C, 12 h, 56%; e) Me2S/CF3CO2H (1:2), 0 °C, 4 h, 88%
Eur. J. Org. Chem. 2002, 79Ϫ86
81

A. Patel, T. K. Lindhorst
FULL PAPER
Scheme 4. a) SnCl4 (1  in CH2Cl2), TMSNCS, DCE (dichloroethane), 50 °C, 3 h, 75% (β/α ϭ 2:1); b) DMF, DIPEA, 50 °C, 12 h;
c) NH3/MeOH, 0 °C, 12 h, 83% over two steps
lysis by the trace amount of water present in [D4]methanol. and trisaccharide analogues 12 and 18, respectively, showed
This observation with 10 and 12 was only made in double and broad signals for 1-H, and less pronounced sig-
[D]4MeOH and D2O, and not in [D]6acetone.
nals for 2-H and 3-H, an effect caused by (E)/(Z) isomerism
In order to synthesize a trisaccharide mimetic based on occurring in the NHBoc group, due to the partial double-
galactoside 10, compound 12 was saponified to the corres- bond character of the Boc CϪN bond.[33] In compound 23
ponding acid 13, which was carried forward into a second a similar multiplet pattern due to the presence of (E) and
peptide coupling reaction, with 2-aminoethyl α--fucoside (Z) stereoisomers resulting from the thiourea linkage was
(17) as the amine component. This could easily be obtained observed.
from the known bromo derivative 14[29] in three steps
(Scheme 3). HATU-assisted peptide coupling of the amine
17 and the disaccharide mimetic 13 gave the trisaccharide
mimetic 18 in 56% yield. The Boc-protected amino function
in 18 was then liberated in an anhydrous mixture of trifluo-
Conclusion
Our goal was to achieve easy and quick access to com-
roacetic acid and dimethyl sulfide (2:1)[30] to yield the cor- plex oligosaccharide mimetics based on an orthogonally
responding free amine 19, without affecting the glycosidic protected oligofunctional core saccharide. It was demon-
bond. To increase the yield in the next step, it was necessary strated that, starting from the trifunctional carbohydrate
to neutralize final traces of TFA carefully with aqueous scaffold 10, oligosaccharide mimetics of a ‘‘mixed’’ type
ammonia during the workup and to desalt the crude amine (compounds 12, 18, 23) containing carbohydrate moieties
on a short Bio-gel P-2 column.
of differently configured sugar series, could be produced
Finally, amine 19 was ligated to the lactosyl isothiocyan- easily and quickly by employing ligation chemistries altern-
ate 21 by thiourea bridging. The disaccharide isothiocyan- ative to glycosidation. The synthetic route demonstrated
ate could easily be obtained from the corresponding per- here can be applied for the synthesis of a large number of
acetate by using trimethylsilyl isothiocyanate (TMSNCS)[31] different oligosaccharide mimetics and glycoconjugates.
in the presence of SnCl4 in preference to other methods The concept is open to a variety of modifications, such as
(Scheme 4).[32] Thus, the pentasaccharide mimetic 22 was solid-phase synthesis, combinatorial approaches, biolabe-
obtained when the amine 19 was treated with the lactosyl ling, or multivalent presentation. Exploration of the differ-
isothiocyanate 21 in dry DMF, and deacetylation of the ent arrangements of functional groups provided by such
crude product with methanolic ammonia gave the fully de- types of oligosaccharide mimetics may also provide new
protected glycocluster 23. After purification by GPC on lead structures for the design of potent antiadhesives. In
Bio-gel P-2 with ammonium hydrogen carbonate buffer as addition, if it is considered that adhesion of wild-type bac-
the eluent, pure 23 was obtained in 83% yield over two teria is dependent on more than only one type of fimbriae,
steps.
but rather utilizes sugar epitopes of different configuration,
The structures of all the synthesized oligosaccharide mi- as is also the case in many other natural adhesion processes,
metics could be clearly confirmed by their NMR and ‘‘mixed’’ glycoclusters may offer great potential in this con-
1
MALDI-TOF-MS data. The H NMR spectra of the di- text.
82
Eur. J. Org. Chem. 2002, 79Ϫ86

“Mixed Type” Oligosaccharide Mimetics
FULL PAPER
4), 61.7 (C-6), 40.8 (CH2N), 28.8 [C(CH3)3], 21.2, 21.1, 20.9 (4
COCH3). C21H33NO12 (491.49): calcd. C 51.32, H 6.77, N 2.85;
found C 50.93, H 6.94, N 2.93.
Experimental Section
Abbreviations: HATU: O-(7-azabenzotriazol-1-yl)-N,N,NЈ,NЈ-tetra-
methyluronium hexafluorophosphate; DIPEA: diisopropylethylam-
ine; CCA: α-Hydroxy-4-cyanocinnamic acid; DHB: Dihydroxyben-
zoic acid; gal: galactose; man: mannose; fuc: fucose; glc: glucose;
galЈ: galactoside of lactose moiety; iPrOH: 2-propanol.
2-(tert-Butyloxycarbonylamido)ethyl β-D-Galactopyranoside (3): A
freshly prepared solution of NaOMe in MeOH (1 , 1 mL) was
added at 0 °C to a solution of the Boc-protected galactoside 2
(3.80 g, 7.73 mmol) in methanol (40 mL), and the mixture was
stirred at room temp. for 1 h. The basic reaction mixture was then
neutralized with methanolic HCl solution (10%) and concentrated.
The crude product was purified by flash chromatography (MeOH/
CH2Cl2, 1:10) to yield tetraol 3 (2.40 g, 7.42 mmol, 96%) as a white
amorphous solid. [α]D ϭ Ϫ1.5 (c ϭ 1.08 in MeOH). 1H NMR
(400 MHz, [D4]MeOH): δ ϭ 4.22 (d, J1,2 ϭ 7.1 Hz, 1 H, 1-H), 3.88
(mc, 1 H, OCHa), 8.82 (d, 1 H, 4-H), 3.78Ϫ3.68 (m, 2 H, 3-H, 6-
General Remarks: For TLC, Merck silica gel 60 F254 plates were
used. Flash chromatography was performed on silica gel 60
(230Ϫ400 mesh, 40Ϫ63 µm, Merck) and detection was carried out
by charring with 20% ethanolic sulfuric acid solution containing
5% of α-naphthol and under UV light when applicable. For size
exclusion chromatography, Sephadex LH-20 with methanol as the
eluent and Bio-gel P-2 and Bio-gel P-6 with 15 m aq. NH4HCO3
buffer (pH ϭ 7.8Ϫ8.0) as the eluent were used. Organic solutions
were concentrated in a rotary evaporator at bath temperatures Ͻ
Ha), 3.61 (mc, 1 H, OCHb), 3.55Ϫ3.44 (m, J1,2 ϭ 7.1, J5,6b
ϭ
6.1 Hz, 3 H, 2-H, 6-Hb, 5-H), 3.25 (mc, 2 H, CH2N), 1.45 (s, 9 H,
tBu). 13C NMR (100.62 MHz, [D4]MeOH): δ ϭ 158.5 (BocCO),
105.1 (C-1), 80.1 [C(CH3)3], 76.7 (C-4), 74.8 (C-3), 72.5 (C-2), 70.2
(C-5), 70.0 (OCH2), 62.5 (C-6), 41.5 (CH2N), 28.8 [C(CH3)3].
C13H25NO8 (323.34): calcd. C 48.29, H 7.79, N 4.33; found C
47.98, H 7.80, N 4.30.
1
45 °C. Aqueous solutions were concentrated by lyophilization. H
and 13C NMR spectra were recorded with Bruker ARX 300 and
1
DRX 500 instruments at 298 K, at 300 MHz (for H), 75.46 MHz
(for 13C NMR), and at 500 MHz (for 1H), 125.84 MHz (for 13C
NMR). Chemical shifts are given in ppm relative to internal TMS
(δ ϭ 0.00 for 1H and 13C NMR) and, when the samples were meas-
ured in D2O, the spectra were calibrated relative to internal HOD
(δ ϭ 4.63) for 1H NMR and, in the case of 13C NMR, to
[D4]MeOH (δ ϭ 49.30 for 13C NMR), which was added to the
solution. Coupling constants (J) are given in Hz. Two-dimensional
1H-1H and 1H-13C-COSY (HMQC) experiments were performed
for complete signal assignments wherever necessary. IR spectra
were recorded with FT-IR ATI Mattson Instruments (USA).
MALDI-TOF mass spectra were recorded with Bruker Biflex and
EI-MS with Finnigan MAT 8230 machines. For MALDI-TOF
measurements, the samples were prepared as solutions in aceto-
nitrile/water/TFA (2:1:0.1) with a concentration of 1 mg/mL solu-
tion. Compounds were co-crystallized with either DHB or CCA.
The mass peaks obtained with all the samples were calibrated in
reference to the [M ϩ H]ϩ peaks of angiotensin II (1046.54), angio-
tensin I (1296.69), bombesin (1619.82), and to the [2 M ϩ H]ϩ peak
of α-cyano-4-hydroxycinnamic acid (380.02). Optical rotations were
recorded at the Na-D line, 589 nm, 20 °C, cell length 10 cm and
1 cm in special cases. Elemental analyses were carried out in the
Institute of Inorganic Chemistry, Christian-Albrechts-University,
Kiel.
2-(tert-Butyloxycarbonylamido)ethyl 6-O-(4-Tolylsulfonyl)-β-D-ga-
lactopyranoside (4): The tetraol 3 (2.33 g, 7.20 mmol) was dissolved
in pyridine (10 mL) and treated with tosyl chloride (1.51 g,
7.92 mmol) at 0 °C under argon. The reaction mixture was then
allowed to attain room temp. and was further stirred for 2 h. Excess
tosyl chloride was quenched by adding MeOH at 0 °C and then
the solvents were evaporated. The crude product thus obtained was
purified by flash chromatography (CH2Cl2/MeOH, 10:1) to give
the 6-O-tosylated derivative 4 (2.20 g, 4.61 mmol, 64%) as a white
amorphous solid. [α]D ϭ Ϫ7.0 (c ϭ 1.42 in MeOH). 1H NMR
(500 MHz, [D4]MeOH): δ ϭ 7.80 (d, J ϭ 8.4 Hz, 2 H, 2 aryl-H),
7.45 (d, J ϭ 8.7 Hz, 2 H, 2 aryl-H), 4.24Ϫ4.14 (m, 3 H, 1-H, 6-Ha,
6-Hb), 3.83Ϫ3.61 (m, 3 H, 2-H, 4-H, OCHa), 3.52 (mc, 1 H, OCHb),
3.48Ϫ3.42 (m, 2 H, 3-H, 5-H), 3.21 (mc, 2 H, CH2N), 2.45 (s, 3 H,
TsCH3), 1.42 (s, 9 H, tBu). 13C NMR (125.75 MHz, [D4]MeOH):
δ ϭ 158.2 (BocCO), 146.6 (aryl-Cq), 134.3 (aryl-Cq), 131.2 (2 aryl-
CH), 129.0 (2 aryl-CH), 104.8 (C-1), 80.0 [C(CH3)3], 74.3 (C-3),
74.0 (C-4, C-2), 72.2 (C-5), 70.7 (C-6), 70.0 (OCH2), 41.5 (CH2N),
28.8 [C(CH3)3, 21.6 (TsCH3). C20H31NO10S (477.53): calcd. C
50.31, H 6.54, N 2.93 found C 50.43, H 6.79, N 2.92.
2-(tert-Butyloxycarbonylamido)ethyl 3,6-Anhydro-β-D-galactopyr-
anoside (5): A suspension of the 6-O-tosylated mannoside 4 (1.56 g,
3.27 mmol) and NaN3 (1.60 g, 24.52 mmol) in dry DMF (20 mL)
was stirred at 60 °C for 12 h. DMF was then removed in vacuo
and the residual solid was dissolved in ethyl acetate and filtered
through a thin Celite bed to remove insoluble salts from the prod-
uct mixture. The filtrate was concentrated and the crude product
was purified by flash chromatography (CH2Cl2/MeOH, 9:1) to
yield the anhydro-galactoside 5 (0.82 g, 2.68 mmol, 82%) as a col-
orless syrup. [α]D ؍ Ϫ70.4 (c ϭ 3.8 in MeOH). 1H NMR
2-(tert-Butyloxycarbonylamido)ethyl 2,3,4,6-Tetra-O-acetyl-β-D-ga-
lactopyranoside (2): A suspension of 2-azidoethyl 2,3,4,6-tetra-O-
acetyl-β--galactopyranoside (1;[23] 4.00 g, 9.59 mmol), activated
Pd catalyst (10% on charcoal; 100 mg) and di-tert-butyl dicarbon-
ate (3.14 g, 14.38 mmol) in ethyl acetate (30 mL) was hydrogenated
under atmospheric pressure for 6 h at room temp. The reaction
mixture was then filtered through a thin Celite bed and the filtrate
was concentrated. The crude product was purified by flash chroma-
tography (ethyl acetate/toluene, 1:1) to afford the Boc-protected ga-
lactoside 2 (3.80 g, 7.73 mmol, 81%) in the form of a white solid.
[α]D ϭ ϩ2.4 (c ϭ 1.23 in CHCl3). 1H NMR (400 MHz, CDCl3):
(500 MHz, [D4]MeOH): δ ϭ 4.52 (s, 1 H, 1-H), 4.33 (d, J5,6a
1.9 Hz, 1 H, 6-Ha), 4.18Ϫ4.14 (m, 2 H, 6-Hb, 4-H), 4.11 (d, J2,3
ϭ
ϭ
4.8 Hz, 1 H, 2-H), 3.92 (d, J2,3 ϭ 4.8 Hz, 1 H, 3-H), 3.90 (mc, 1 H,
5-H), 3.76 (mc, 1 H, OCHa), 3.37 (mc, 1 H, OCHb), 3.23 (mc, 2 H,
CH2N), 1.43 (s, 9 H, tBu). 13C NMR (125.75 MHz, [D4]MeOH):
δ ϭ 158.3 (BocCO), 103.5 (C-1), 82.5 (C-2), 80.1 [C(CH3)3], 79.1
(C-4), 74.0 (C-3), 72.3 (C-5), 71.2 (C-6), 68.2 (OCH2), 41.1 (CH2N),
28.8 [C(CH3)3]. EI-MS: m/z ϭ 306.1 [M ϩ H]ϩ found for
C13H23NO7 (calcd. 305.14).
δ ϭ 5.40 (d, J3,4 ϭ 3.1 Hz, 1 H, 4-H), 5.20 (dd, J2,3 ϭ 10.7, J1,2
ϭ
8.2 Hz, 1 H, 2-H), 5.02 (dd, J2,3 ϭ10.7, J3,4ϭ 3.5 Hz, 1 H, 3-H),
4.93 (s, 1 H, NH), 4.47 (d, J1,2 ϭ 7.7 Hz, 1 H, 1-H), 4.17 (dd,
J6a,6b ϭ 11.2, J5,6a ϭ 6.7 Hz, 1 H, 6-Ha), 4.13 (dd, J6a,6b ϭ 11.2 Hz,
1 H, 6-Hb), 3.95Ϫ3.85 (m, 2 H, 5-H, OCHa), 3.65 (mc, 1 H, OCHb),
3.33 (mc, 2 H, CH2N), 2.16, 2.08, 2.05, 1.99 (each s, each 3 H, 4
COCH3), 1.44 (s, 9 H, tBu). 13C NMR (100.67 MHz, CDCl3): δ ϭ
170.7, 170.6, 170.5, 169.9 (4 COCH3), 156.3 (BocCO), 102.0 (C-1), 2-(tert-Butyloxycarbonylamido)ethyl 2,3,4-Tri-O-acetyl-6-O-(4-to-
79.8 [C(CH3)3], 71.2 (C-5, C-3), 70.2 (OCH2), 69.3 (C-2), 67.4 (C- lylsulfonyl)-β-
D
-galactopyranoside (6): The unprotected tosylated 5
Eur. J. Org. Chem. 2002, 79Ϫ86
83

A. Patel, T. K. Lindhorst
FULL PAPER
(2.10 g, 4.40 mmol) was dissolved in pyridine and the solution was
2-(tert-Butyloxycarbonylamido)ethyl 6-Deoxy-6-{[2-(methoxy-
cooled to Ϫ10 °C. Ice-cold acetic anhydride (2 mL) was then added carbonyl)ethyl]amino}-β-D-galactopyranoside (10): A mixture of the
slowly while stirring. The reaction mixture was kept at 4 °C for 12 h
and was then concentrated, and the crude product was purified by
flash chromatography (n-hexane/acetone, 2.5:1) to afford the
azide 8 (0.85 g, 2.44 mmol) and activated Pd catalyst (10% on char-
coal, 50 mg) in MeOH (10 mL) was hydrogenated under atmo-
spheric pressure for 10 h at room temp. The suspension was filtered
acetylated derivative 6 (2.57 g, 4.25 mmol, 97%) as a colorless through a short pad of Celite and the filtrate was concentrated. The
syrup. [α]D ϭ Ϫ2.7 (c ϭ 1.14 in CHCl3). 1H NMR (500 MHz, crude amino-functionalized derivative 9 thus obtained was further
CDCl3): δ ϭ 7.75 (d, J ϭ 8.4 Hz, 2 H, 2 aryl-H), 7.35 (d, J ϭ
8.6 Hz, 2 H, 2 aryl-H), 5.35 (dd, J3,4 ϭ 3.4, J4,5 ϭ 1.2 Hz, 1 H, 4-
treated with freshly distilled methyl acrylate (1.91 g, 22.23 mmol)
in dry MeOH (10 mL) at 0 °C under argon. The reaction mixture
H), 5.14 (dd, J1,2 ϭ 7.9, J2,3 ϭ 10.5 Hz, 1 H, 2-H), 4.97 (dd, J2,3 ϭ was then heated at 40 °C in darkness for 18 h. Concentration and
10.5, J3,4 ϭ 3.4 Hz, 1 H, 3-H), 4.82 (s, 1 H, NH), 4.42 (d, J1,2ϭ purification of the crude product by flash chromatography
7.9 Hz, 1 H, 1-H), 4.11 (dd, J5,6a ϭ 6.6, J6a,6b ϭ 12.8 Hz, 1 H, 6- (CH2Cl2/MeOH, 2.5:1) yielded the Michael mono-adduct 10
Ha), 4.00 (dd, J5,6b ϭ 6.3, J6a,6b ϭ 12.8 Hz, 1 H, 6-Hb), 3.93 (ddd,
(0.60 g, 1.47 mmol, 60% over two steps) as a white, hygroscopic
J5,6 ϭ 7.6, J5,6b ϭ 6.4, J4,5 ϭ 1.2 Hz, 1 H, 5-H), 3.82 (mc, 1 H, solid. [α]D ϭ Ϫ1.1 (c ϭ 1.58 in MeOH). 1H NMR (500 MHz,
OCHa), 3.58 (mc, 1 H, OCHb), 3.29 (mc, 2 H, CH2N), 2.44 (s, 3 H, [D4]MeOH): δ ϭ 4.27 (d, J1,2 ϭ 7.6 Hz, 1 H, 1-H), 3.90 (mc, 1 H,
TsCH3), 2.05, 2.03, 1.96 (each s, each 3 H, 3 COCH3), 1.43 (s, 9 OCHa), 3.81 (dd, J4,5 ϭ 1.6 Hz, 1 H, 4-H), 3.76 (mc, 1 H, 5-H),
H, tBu). 13C NMR (125.75 MHz, CDCl3): δ ϭ 170.0, 169.9, 169.6
3.71 (s, 3 H, CO2CH3), 3.62 (mc, 1 H, OCHb), 3.53Ϫ3.48 (m, 2
(3 COCH3), 156.2 (BocCO), 145.3 (aryl-Cq), 132.3 (aryl-Cq), 130.0 H, 2-H, 3-H), 3.31 (mc, 1 H, CHaNHBoc), 3.27Ϫ3.19 (m, 2 H,
(2 aryl-CH), 128.1 (2 aryl-CH), 101.5 (C-1), 80.0 [C(CH3)3], 70.7 CHbNHBoc, 6-H), 3.13 (mc, 2 H, NCH2), 3.08 (dd, J6a,6b ϭ 12.7,
(C-5), 70.5 (C-3), 69.7 (OCH2), 68.7 (C-2), 66.8 (C-4), 66.1 (C- J5,6b ϭ 3.4 Hz, 1 H, 6-Hb), 2.71 (t, J ϭ 6.6 Hz, 2 H, CH2CO),
6), 40.2 (CH2N), 28.4 [C(CH3)3], 21.7 (TsCH3), 20.53, 20.52, 20.51 1.44 (s, 9 H, tBu). 13C NMR (125.75 MHz, [D4]MeOH): δ ϭ 173.7
(3 COCH3).
(CO2CH3), 158.5 (BocCO), 105.1 (C-1), 80.2 [C(CH3)3], 74.5 (C-
3), 72.6 (C-5), 72.2 (C-2), 71.6 (C-4), 70.1 (OCH2), 52.5 (CO2CH3),
50.4 (C-6), 45.3 (NCH2), 41.5 (CH2NBoc), 32.7 (CH2CO), 28.8
[C(CH3)3]. C17H32N2O9·H2O (426.46): calcd. C 47.88, H 8.04, N
6.57, found C 48.21, H 7.95, N 6.49.
2-(tert-Butyloxycarbonylamido)ethyl 2,3,4-Tri-O-acetyl-6-azido-6-
deoxy-β-
D-galactopyranoside (7): A suspension of the acetyl-pro-
tected galactoside
6
(2.47 g, 4.09 mmol) and NaN3 (5.32 g,
81.83 mmol) in dry DMF (30 mL) was stirred at 80 °C for 24 h.
DMF was removed in vacuo and the crude product was dissolved
in ether. The organic layer was washed with water to remove inor-
ganic salts and brine. Drying with anhydrous Na2SO4, concentra-
tion, and purification by flash chromatography (n-hexane/acetone,
2.5:1) afforded the 6-deoxy-6-azido derivative 7 (1.40 g, 2.95 mmol,
72%) as a colorless syrup. [α]D ؍ Ϫ3.4 (c ϭ 1.10 in CHCl3). 1H
2-(tert-Butyloxycarbonylamido)ethyl 6-Deoxy-6-({p-[(α-
syloxy)methyl]benzoyl}[2-(methoxycarbonyl)ethyl]amino)-β-
galactopyranoside (12): The galactoside 10 (120 mg, 0.29 mmol),
the mannoside 11 (170 mg, 0.58 mmol), HATU (246 mg,
0.65 mmol), and DIPEA (0.25 mL, 1.47 mmol) were dissolved in
DMF (5 mL) under argon. The reaction mixture was stirred at 45
D-manno-
D
-
NMR (500 MHz, CDCl3): δ ϭ 5.35 (dd, J3,4 ϭ 3.5, J4,5 ϭ 1.2 Hz, °C for 6 h and DMF was then removed in vacuo. The resulting
1 H, 4-H), 5.21 (dd, J1,2 ϭ 7.9, J2,3 ϭ 10.5 Hz, 1 H, 2-H), 5.02 (dd, crude product was a pale yellow syrup, which was subjected to gel
J2,3 ϭ 10.5, J3,4 ϭ 3.4 Hz, 1 H, 3-H), 4.88 (s, 1 H, NH), 4.50 (d, permeation chromatography on Bio-gel P-2. This afforded the title
J
1,2ϭ 7.9 Hz, 1 H, 1-H), 3.93 (mc, 1 H, OCHa), 3.85 (ddd, J4,5
ϭ
compound 12 (160 mg, 0.23 mmol, 79%) as a white, hygroscopic
1.2, J5,6a ϭ 8.1, J5,6b ϭ 4.4 Hz, 1 H, 5-H), 3.64 (mc, 1 H, OCHb),
lyophilizate. [α]D ϭ ϩ37 (c ϭ 1.14 in MeOH). 1H NMR (500 MHz,
3.55 (dd, J5,6a ϭ 8.1, J6a,6b ϭ 12.9 Hz, 1 H, 6-Ha), 3.34 (mc, 2 H, [D4]MeOH): δ ϭ 7.50Ϫ7.37 (m, 4 H, 4 aryl-H), 4.84 (d, J1,2
ϭ
CH2N), 3.16 (dd, J5,6b ϭ 4.4, J6a,6b ϭ 12.9 Hz, 1 H, 6-Hb), 2.20, 1.8 Hz, 1 H, man 1-H), 4.79 (d, J ϭ 12.2 Hz, 1 H, PhCHa), 4.57
2.10, 2.00 (each s, each 3 H, 3 COCH3), 1.44 (s, 9 H, tBu). 13C (d, J ϭ 11.8 Hz, 1 H, PhCHb), 4.24 (d, J1,2 ϭ 7.8 Hz, 1 H, gal 1-
NMR (125.75 MHz, CDCl3): δ ϭ 170.2, 170.0, 169.6 (3 COCH3), H), 3.96Ϫ3.76 (m, 7 H, OCHa, man 6-Ha, NCHa, man 2-H, gal 3-
155.8 (BocCO), 101.5 (C-1), 79.4 [C(CH3)3], 72.9 (C-5), 70.7 (C-3),
H, gal 4-H, gal 5-H), 3.75Ϫ3.65 (m, 5 H, man 6-Hb, gal 6-Ha,
69.7 (OCH2), 68.8 (C-2), 67.9 (C-4), 50.5 (C-6), 40.2 (CH2N), 28.4 OCHb, NCHb, man 3-H), 3.71 (s, 3 H, CO2CH3), 3.64Ϫ3.51 (m, 3
[C(CH3)3], 20.9, 20.7, 20.6 (3 COCH3).
H, man 4-H, gal 6-Hb, man 5-H), 3.50 (mc, 1 H, gal 2-H), 3.28
(mc, 2 H, CH2NHBoc), 2.68 (mc, 2 H, CH2CO), 1.44 (s, 9 H, tBu).
13C NMR (125.84 MHz, [D4]MeOH): δ ϭ 174.8 (CO2CH3), 173.5
(NCO), 158.5 (BocCO), 141.4 (aryl-Cq), 137.7 (aryl-Cq), 129.1,
128.4, 127.8 (4 aryl-CH), 105.1 (gal C-1), 101.0 (man C-1, 1JC1,H1 ϭ
168.3 Hz), 80.2 [C(CH3)3], 75.0 (man C-5), 74.6 (gal C-2), 74.2 (gal
C-3), 72.7 (man C-3), 72.4 (gal C-5), 72.2 (man C-2), 71.0 (gal C-
4), 70.0 (OCH2), 69.4 (PhCH2), 68.7 (man C-4), 63.0 (man C-6),
52.5 (gal C-6), 52.3 (CO2CH3), 47.8 (NCH2), 41.5 (CH2NHBoc),
33.1 (CH2CO), 28.8 [C(CH3)3]. MALDI-TOF MS: m/z ϭ 727.5 [M
ϩ Na]ϩ and 743.5 [M ϩ K]ϩ found for C31H48N2O16 (calcd. 704.3).
C31H48N2O16 (704.73): calcd. C 52.83, H 6.87, N 3.98, found C
52.02, H 6.56, N 4.15.
2-(tert-Butyloxycarbonylamido)ethyl 6-Azido-6-deoxy-β-D-galactop-
yranoside (8): The acetylated galactoside 7 (1.27 g, 2.67 mmol) was
dissolved in methanol (10 mL) and a freshly prepared solution of
NaOMe in MeOH (1 , 0.5 mL) was then added at 0 °C. The
mixture was stirred at room temp. for 1 h. The basic reaction mix-
ture was neutralized with methanolic HCl solution (10%) and con-
centrated. The crude product thus obtained was purified by flash
chromatography (MeOH/CH2Cl2, 1:10) to yield triol 8 (0.91 g,
2.62 mmol, 98%) as a white hygroscopic solid. [α]D ϭ Ϫ29.5 (c ϭ
1.15 in MeOH). 1H NMR (500 MHz, [D4]MeOH): δ ϭ 4.26 (d,
J1,2 ϭ 7.5 Hz, 1 H, 1-H), 3.90 (mc, 1 H, OCHa), 3.74 (dd, J4,5
1.1, J3,4 ϭ 3.0 Hz, 1 H, 4-H), 3.69 (dd, J4,5 ϭ 1.2, J5,6b ϭ 4.8 Hz,
1 H, 5-H), 3.65Ϫ3.58 (m, 2 H, 6-Ha, OCHb), 3.55Ϫ3.48 (m, 2 H, 2-tert-Butyloxycarbonylamidoethyl
2-H, 3-H), 3.27 (mc, 2 H, CH2N), 3.22 (dd, J6a,6b ϭ 11.0, J5,6b
ϭ
6-Deoxy-6-[{p-[(α-
D-manno-
ϭ
syloxy)methyl]benzoyl}(2-propanoyl)amino]-β- -galactopyr-
D
4.2 Hz, 1 H, 6-Hb), 1.43 (s, 9 H, tBu). 13C NMR (125.75 MHz, anoside (13): The disaccharide analogue 12 (156 mg, 0.22 mmol)
[D4]MeOH): δ ϭ 158.5 (BocCO), 104.9 (C-1), 80.1 [C(CH3)3], 75.7 was dissolved in MeOH/H2O (1:2; 2 mL) and treated with
(C-5), 74.5 (C-3), 72.3 (C-2), 70.7 (C-4), 70.0 (OCH2), 52.5 (C-6), LiOH·H2O (11 mg, 0.26 mmol) at 0 °C for 12 h. The basic reaction
41.4 (CH2N), 28.8 [C(CH3)3].
mixture was then neutralized at 0 °C to a value of pH ϭ 6 by
84
Eur. J. Org. Chem. 2002, 79Ϫ86

“Mixed Type” Oligosaccharide Mimetics
FULL PAPER
careful addition of HCl (2 ). The obtained clear solution was found for C38H61N3O20 (calcd. 879.38). C38H61N3O20 (879.91):
freeze-dried to afford the crude carboxylic acid 13 as a white, calcd. C 51.87, H 6.99, N 4.78, found C 50.98, H 6.80, N 4.93.
amorphous solid (152 mg, 0.22 mmol, quant.), which was used in
2-Aminoethyl
oyl}(2-{[2-(α-
6-Deoxy-6-[{p-[(α-
-fucosyloxy)ethyl]carbamoyl}ethyl)amino]-β-D-
D-mannosyloxy)methyl]benz-
the next step without purification.
L
galactopyranoside (19): The trisaccharide analogue 18 (45 mg,
0.05 mmol) was dissolved in a freshly prepared solution of
Me2SϪCF3CO2H (1:2; 1 mL) and stirred for 3 h at 0 °C. The reac-
tion mixture was then concentrated in a rotary evaporator in a
closed fume hood and final traces of CF3CO2H were quenched
with satd. NH3/H2O solution (1 mL) at 0 °C. After lyophilization
of the aqueous mixture, it was desalted with Bio-gel P-2 to give the
corresponding amino derivative 19 [35 mg, 0.05 mmol, 88%; TLC
(iPrOH/H2O/NH3, 7:2:1): Rf ϭ 0.1 (UV, α-naphthol)].
2-Azidoethyl α-
L
-Fucoside (16): The bromoethyl fucoside 14[29]
(2.00 g, 5.03 mmol) was treated with NaN3 (1.63 g, 25.17 mmol) in
DMF (5 mL) at 60 °C for 1 h. After removal of DMF in vacuo,
the residual syrup was suspended in ethyl acetate and the suspen-
sion was filtered through a thin Celite bed. The filtrate was washed
with water to remove inorganic salts and brine and the organic
layer was then dried with anhydrous Na2SO4. After filtration and
concentration, the triacetylated azido derivative 15 was obtained as
a white solid. Without further purification, 15 was then dissolved
in methanol and treated with a freshly prepared NaOMe solution
(0.5 mL, 1 ) for 1 h at room temp. The reaction was quenched
with diluted HCl solution and the solvent was removed. Sub-
sequent chromatographic purification (CH2Cl2/MeOH, 9:1) of the
crude product afforded the title fucoside 16 (0.82 g, 3.51 mmol,
2,3,6,2Ј,3Ј,4Ј,6Ј-Hepta-O-acetyl-β-D-lactopyranosyl Isothiocyanate
(21): A solution of tin(IV) chloride in CH2Cl2 (1 , 0.60 mL,
0.60 mmol) was added to a solution of lactose octaacetate (20;
270 mg, 0.40 mmol) in dry DCE (dichloroethane) (4 mL). Trime-
thylsilyl isothiocyanate (0.09 mL, 0.60 mmol) was then added
slowly at 0 °C under argon and the reaction mixture was heated at
50 °C. After 3 h, the reaction mixture was allowed to cool to room
temp., diluted with CH2Cl2 (5 mL), and washed successively with
water, satd. NaHCO3, and brine. The organic layer was then dried
with anhydrous Na2SO4, filtered, and concentrated. TLC analysis
of the crude product showed the presence of an anomeric mixture,
which was subjected to flash chromatography (n-hexane/ethyl acet-
ate, 1.5:1) to yield the title β anomer 21 (135 mg, 0.20 mmol) as
a white solid, together with the corresponding α anomer (70 mg,
0.10 mmol) in the ratio of 2:1 (75%). IR: ν˜ ϭ 2029.3 cmϪ1(NCS).
M.p. 75Ϫ77 °C. [α]D ϭ Ϫ1.0 (c ϭ 1.14 in CHCl3) (ref.[32] syrup).
70% over two steps) as a colorless syrup. [α]D ϭ Ϫ112.8 (c ϭ 1.25
1
in MeOH). H NMR (500 MHz, [D4]MeOH): δ ϭ 4.78 (d, J1,2
ϭ
3.44 Hz, 1 H, 1-H), 4.01 (mc, 1 H, 5-H), 3.84 (mc, 1 H, OCHa),
3.75 (mc, 2 H, 3-H, 2-H), 3.67 (dd, 1 H, J3,4 ϭ 1.32, J4,5 ϭ 3.15 Hz,
4-H), 3.62 (mc, 1 H, OCHb), 3.55 (mc, 1 H, OCHaN3), 3.36 (mc,
1 H, CHbN3), 1.22 (d, J1,2 ϭ 3.44 Hz, 3 H, 6-CH3). 13C NMR
(125.75 MHz, [D4]MeOH): δ ϭ 100.8 (C-1), 73.6 (C-4), 71.5 (C-3),
69.81 (C-2), 68.1 (OCH2), 67.8 (C-5), 51.9 (CH2N3), 16.6 (6-CH3).
2-(tert-Butyloxycarbonylamido)ethyl 6-Deoxy-6-[{p-[(α-
carbamoyl}syloxy)methyl]benzoyl}(2-{[2-(α- -fucosyloxy)ethyl]-
ethyl)amino]-β- -galactopyranoside (18): The azidoethyl fucoside 16
D-manno-
L
D
1
[α]D ϭ ϩ5.5 (c ϭ 1 in CH2Cl2). H NMR (500 MHz, CDCl3): δ ϭ
(0.10 g, 0.42 mmol) and Pd catalyst (10% on charcoal; 50 mg) were
dissolved in MeOH (10 mL) and the mixture was hydrogenated un-
der atmospheric pressure for 3 h at room temp. The suspension was
filtered through a short pad of Celite and the filtrate was concen-
trated. The obtained crude amino derivative 17 was used without
further purification in the subsequent coupling reaction. A mixture
of carboxylic acid 13 (140 mg, 0.20 mmol), 2-aminoethyl α--fuco-
side 17 (63 mg, 0.30 mmol), HATU (100 mg, 0.26 mmol), and DI-
PEA (0.10 mL, 0.61 mmol) in dry DMF (2 mL) was stirred at 45
°C for 12 h under argon. The reaction mixture was then concen-
trated in vacuo and the resulting pale yellow syrup was subjected
to gel permeation chromatography on Bio-gel P-2 to provide the
title compound 18 (100 mg, 0.11 mmol, 56%) as a white, hygro-
5.35 (dd, J4,5 ϭ 1.3, J3,4 ϭ 3.5 Hz, 1 H, gal 4-H), 5.20 (dd, J2,3
9.2, J3,4 ϭ 10.0 Hz, 1 H, glc 3-H), 5.10 (dd, J1,2 ϭ 7.9, J2,3
ϭ
ϭ
10.4 Hz, 1 H, gal 2-H), 5.02 (dd, J1,2 ϭ 8.0, J2,3 ϭ 9.2 Hz, 1 H, glc
2-H), 5.01 (d, J1,2 ϭ 8.0 Hz, 1 H, glc 1-H), 4.96 (dd, J2,3 ϭ 10.4,
J3,4 ϭ 3.5 Hz, 1 H, gal 3-H), 4.49 (d, J1,2 ϭ 7.9 Hz, 1 H, gal 1-H),
4.48 (dd, J5,6 ϭ 2.1, J6a,6b ϭ 12.2 Hz, 1 H, glc 6-Ha), 4.13 (dd,
J5,6b ϭ 6.5, J6a,6b ϭ 12.2 Hz, 1 H, glc 6-Hb), 4.13Ϫ4.06 (m, 2 H,
gal 6-Ha, 6b), 3.88 (ddd, J4,5 ϭ 1.3, J5,6a ϭ 7.4, J5,6b ϭ 13.6 Hz, 1
H, gal 5-H), 3.82 (dd, J4,5 ϭ 9.0, J3,4 ϭ 10.0 Hz, 1 H, glc 4-H),
3.66 (mc, 1 H, glc 5-H), 2.16, 2.15, 2.10, 2.07, 2.06, 2.05, 1.96 (each
s, each 3 H, 7 COCH3). 13C NMR (125.84 MHz, CDCl3): δ ϭ
170.3, 170.2, 170.0, 169.9, 169.6, 169.3, 169.0 (7 COCH3), 144.0
(CϭS), 101.0 (gal C-1), 83.2 (glc C-1), 75.6 (glc C-4), 74.7 (glc C-
5), 72.4 (glc C-3), 72.1 (gal C-2), 70.8 (gal C-3), 70.7 (gal C-5), 69.0
(gal C-2), 66.5 (gal C-4), 61.6 (glc C-6), 60.7 (gal C-6), 20.70, 20.63,
20.57, 20.56, 20.54, 20.50, 20.40 (7 COCH3).
1
scopic lyophilizate. [α]D ϭ Ϫ11.5 (c ϭ 1.03 in MeOH). H NMR
(500 MHz, [D4]MeOH): δ ϭ 7.50Ϫ7.38 (m, 4 H, 4 aryl-H), 4.84
(d, J1,2 ϭ 1.8 Hz, 1 H, man 1-H), 4.81Ϫ4.74 (m, 2 H, PhCHa, fuc
1-H), 4.58 (d, J ϭ 11.8 Hz, 1 H, PhCHb), 4.24 (d, J1,2 ϭ 7.7 Hz, 1
H, gal 1-H), 3.98Ϫ3.78 (m, 7 H, OOCHa, man 6-Ha, gal 3-H, man 2-[(β-
2-H, gal 4-H, gal 5-H, fuc 5-H), 3.76Ϫ3.67 (m, 8 H, man 6-Hb, gal syloxy)methyl]benzoyl}(2-{[2-(α-
6-Ha, NCH2, man 3-H, fuc 2-H, OCH2), 3.66Ϫ3.42 (m, 7 H, gal ethyl)amino]-β- -galactopyranoside (23): The amino-functionalized
D-Lactopyranosyl)thioureido]ethyl 6-Deoxy-6-[{p-[(α-
D-manno-
L
-fucosyloxy)ethyl]carbamoyl}-
D
6-Hb, man 4-H, man 5-H, gal 2-H, OCHb, fuc 3-H, fuc 4-H), 3.28 trisaccharide analogue 19 (35 mg, 0.05 mmol) was treated with the
(mc, 2 H, CH2NHBoc), 2.65 (mc, 2 H, CH2CONH) 2.45 (mc, 2 H, lactosyl isothiocyanate 21 (45 mg, 0.07 mmol) in dry DMF (1 mL)
CONHCH2), 1.44 (s, 9 H, tBu), 1.20 (s, 3 H, fuc 6-CH3). 13C NMR at 50 °C for 12 h. The reaction mixture was then concentrated in
(125.75 MHz, [D4]MeOH): δ ϭ 174.7 (CONH), 173.3 (NCOPh), vacuo to afford the crude partially protected thiourea derivative 22.
158.5 (BocCO), 141.2, 137.5 (2 aryl-Cq), 129.2, 129.0, 128.5, 127.9 This was treated with NH3/MeOH (7 , 2 mL) at 0 °C and stored
(4 aryl CH), 105.1, 104.9 (gal C-1), 101.0 (man C-1), 100.6 (fuc C-
in the refridgerator for 12 h. Concentration of the reaction mixture
1), 80.2 [C(CH3)3], 75.1 (man C-5), 74.6 (gal C-2), 73.9 (gal C-3), yielded a pale yellow syrup, which was subjected to gel permeation
73.6 (fuc C-4), 72.7 (man C-3), 72.4 (gal C-5), 72.2 (man C-2), 71.7 chromatography on Bio-gel P-2 to afford the fully deprotected pen-
(fuc C-5), 71.0 (gal C-4), 70.0 (fuc C-3), 69.9 (OCH2), 69.4 tasaccharide mimetic 23 (43 mg, 0.04 mmol, 83% over two steps)
(PhCH2), 68.7 (man C-4), 67.7 (fuc C-2), 67.8 (OCH2), 63.0 (man as a white, hygroscopic lyophilizate. [α]D ϭ Ϫ15.4 (c ϭ 1.30 in
1
C-6), 52.3 (gal C-6), 48.6 (NCH2), 41.5 (CH2NHBoc), 35.9
H2O). H NMR (500 MHz, D2O): δ ϭ 7.55Ϫ7.46 (m, 2 H, 2 aryl-
(CONHCH2), 35.1 (CH2CO), 28.8 [C(CH3)3], 16.7 (fuc 6-CH3). H), 7.45Ϫ7.35 (m, 2 H, 2 aryl H), 4.98 (s, 1 H, man 1-H),
MALDI-TOF MS: m/z ϭ 902.3 [M ϩ Na]ϩ and 918.3 [M ϩ K]ϩ
4.86Ϫ4.74 (m, 3 H, glc 1-H, PhCHa, fuc 1-H), 4.63 (mc, 1 H,
Eur. J. Org. Chem. 2002, 79Ϫ86
85

A. Patel, T. K. Lindhorst
FULL PAPER
[12]
[13]
[14]
M. Dubber, Th. K. Lindhorst, Carbohydr. Res. 1998, 310,
35Ϫ41.
M. Dubber, Th. K. Lindhorst, J. Org. Chem. 2000, 65,
5275Ϫ5281.
P. I. Kitov, J. M. Sadowska, G. Mulvey, G. D. Armstrong, H.
Ling, N. S. Pannu, R. J. Read, D. R. Bundle, Nature 2000,
403, 669Ϫ672.
C.-H. Wong, X.-S. Ye, Z. Zhang, J. Am. Chem. Soc. 1998,
120, 7137Ϫ7138.
T. Wunberg, C. Kallus, T. Opatz, S. Henke, W. Schmidt, H.
Kunz, Angew. Chem. 1998, 110, 2620Ϫ2622; Angew. Chem. Int.
Ed. 1998, 37, 2503Ϫ2505.
R. Hirschmann, L. Ducry, A. B. Smith III, J. Org. Chem. 2000,
65, 8307Ϫ8316.
M. Ghosh, R. G. Dulina, R. Kakarla, M. J. Sofia, J. Org.
Chem. 2000, 65, 8387Ϫ8390.
A. Patel, Th. K. Lindhorst, J. Org. Chem. 2001, 66,
2674Ϫ2680.
N. Sharon, FEBS Lett. 1987, 217, 145Ϫ157.
S. Kötter, U. Krallmann-Wenzel, S. Ehlers, Th. K. Lindhorst,
J. Chem. Soc., Perkin Trans. 1 1998, 2193Ϫ2200.
Th. K. Lindhorst, M. Dubber, U. Krallmann-Wenzel, S. Ehlers,
Eur. J. Org. Chem. 2000, 2027Ϫ2034.
PhCHb), 4.45 (d, J1,2 ϭ 7.7 Hz, 1 H, galЈ 1-H), 4.40 (d, J1,2
ϭ
7.8 Hz, 1 H, gal 1-H), 4.07Ϫ3.87 (m, 5 H, OOCHa, man 6-Ha, gal
3-H, man 2-H, fuc 5-H), 3.86Ϫ3.61 (m, 25 H, gal 4-H, gal 5-H,
galЈ 6-Ha, galЈ 5-H, man 6-Hb, galЈ 4-H, man 3-H, fuc 4-H, glc 6-
Ha, gal Ј 6-Hb, NCH2, OCHa, fuc 2-H, glc 2-H, fuc 3-H, gal 6-Ha,
glc 6-Hb, man 4-H, glc 3-H, galЈ 3-H, glc 4-H, man 5-H, 2 OCHb),
3.60Ϫ3.21 (m, 6 H, gal 2-H, galЈ 2-H, glc 5-H, CH2NHCO, gal 6-
Hb), 2.67 (mc, 2 H, CH2CONH) 2.45 (mc, 2 H, CONHCH2), 1.16
(d, J ϭ 7.7 Hz, 3 H, fuc 6-CH3). 13C NMR (125.75 MHz, D2O):
δ ϭ 181.8 (CϭS, weak signal), 176.3 (CONH), 175.3 (NCOPh),
141.6, 136.8 (2 aryl-Cq), 131.1, 131.0 (2 aryl CH), 129.5, 129.3 (2
aryl CH), 105. 3 (gal C-1), 105.1 (galЈ C-1), 101.9 (man C-1, fuc
C-1), 100.8 (glc C-1), 80.3 (glc C-3, gal C-5), 77.4 (gal C-2, C-3),
75.4 (glc C-5), 74.9 (glc C-2, galЈ C-2), 74.2 (fuc C-4), 73.3 (man
C-3), 73.0 (gal C-5, man C-2), 72.4 (fuc C-5), 72.0 (fuc C-3), 71.7
(gal C-4), 71.4 (galЈ C-4), 71.2 (OCH2, PhCH2), 71.0 (glc C-4), 70.4
(man C-4), 69.1 (fuc C-2), 68.7 (OCH2), 63.5 (man C-6), 63.2 (glc
C-6), 62.3 (galЈ C-6), 53.2 (gal C-6), 48.0 (NCH2), 41.7
(CH2NHCO), 36.9 (CONHCH2), 36.2 (CH2CO), 17.7 (fuc 6-CH3).
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
MALDI-TOF MS: m/z
ϭ 1183.4 [M ϩ
Na]ϩ found for
C47H76N4O27S (calcd. 1160.44). A correct elemental analysis for
C47H76N4O27S (1161.19) was not obtained.
A. Y. Chernyak, G. V. M. Sharma, L. O. Kononov, P. Radha
Krishna, A. B. Levinsky, N. K. Kochetkov, A. V. Ramarao,
Carbohydr. Res. 1992, 223, 303Ϫ309.
[24]
[25]
´
G. Zemplen, E. Pacsu, Ber. Dtsch. Chem. Ges. 1929, 62,
1613Ϫ1614.
Acknowledgments
R. L. Whistler, M. L. Wolfrom (Eds.), Methods in Carbohydrate
Chemistry. Reactions of Carbohydrates, Academic Press, New
York, 1963, vol. II, p. 172Ϫ187.
This work was funded by the DFG (SFB 470). We gratefully
acknowledge Dr. C. Wolff for performing the NMR experiments
and Mrs. U. Cornelissen for elemental analyses.
[26]
[27]
C. Kieburg, K. Sadalapure, Th. K. Lindhorst, Eur. J. Org.
Chem. 2000, 2035Ϫ2040.
Th. K. Lindhorst, S. Kötter, J. Kubisch, U. Krallmann-Wenzel,
[1]
ˇ
A. Varki, Glycobiology 1993, 3, 97Ϫ130.
S. Ehlers, V. Kren, Eur. J. Org. Chem. 1998, 1669Ϫ1674.
[2]
[28]
[29]
A. Kobata, Glycoconjugate J. 2000, 17, 443Ϫ464.
L. A. Carpino, J. Am. Chem. Soc. 1993, 115, 4397Ϫ4398.
J. Dahmen, T. Frejd, G. Grönberg, T. Lave, G. Magnusson, G.
Noori, Carbohydr. Res. 1983, 116, 303Ϫ307.
[3]
C. R. Bertozzi, L. L. Kiessling, Science 2001, 291, 2357Ϫ2364.
[4]
T. Muramatsu, Glycoconjugate J. 2000, 17, 577Ϫ595.
[5]
[30]
[31]
H. Lis, N. Sharon, Chem. Rev. 1998, 98, 637Ϫ674.
K. Katano, H. A. Y. Aoyagi, M. Overhand, S. J. Sucheck, W.
C. Stevens, Jr., C. D. Hess, X. Zhou, S. M. Hecht, J. Am. Chem.
Soc. 1998, 120, 11285Ϫ11296.
[6]
K.-A. Karlsson, Curr. Opin. Struct. Biol. 1995, 5, 622Ϫ635.
[7]
P. Sears, C.-H. Wong, Angew. Chem. 1999, 111, 2446Ϫ2471;
´
Angew. Chem. Int. Ed. 1999, 38, 2300Ϫ2324.
H. Paulsen, Z. Györgydeak, M. Friedmann, Chem. Ber. 1974,
[8]
Y. C. Lee, R. T. Lee, Acc. Chem. Res. 1995, 28, 321Ϫ327.
107, 1590Ϫ1613.
[9]
[32]
[33]
R. T. Lee, Y. C. Lee, Glycoconjugate J. 2000, 17, 543Ϫ551.
Th. K. Lindhorst, C. Kieburg, Synthesis 1995, 1228Ϫ1230.
G. Fischer, Chem. Soc. Rev. 2000, 29, 119Ϫ127.
Received July 31, 2001
[10]
Th. K. Lindhorst, Top. Curr. Chem. 2002, 218, 201Ϫ235.
[11]
N. Röckendorf, Th. K. Lindhorst, Top. Curr. Chem. 2001,
217, 201Ϫ238.
[O01380]
86
Eur. J. Org. Chem. 2002, 79Ϫ86