Synthesis of dimeric lactose and dimeric (sialyl) LewisX glycolipids

Article abstract of DOI:10.1016/S0008-6215(02)00086-1

To investigate structural requirements for the homophilic interaction between carbohydrates on planar model membranes, divalent derivatives with enforced proximity between the two carbohydrate epitopes (lactose, Lewis^X, and sialyl Lewis^X) were synthesized by use of a dimeric membrane anchor as scaffold.

Full text of DOI:10.1016/S0008-6215(02)00086-1

Carbohydrate Research 337 (2002) 1089–1094
www.elsevier.com/locate/carres
Synthesis of dimeric lactose and dimeric (sialyl) LewisX glycolipids
Christian Gege, Richard R. Schmidt*
Fachbereich Chemie, Uni6ersita¨t Konstanz, Box M725, D-78457 Konstanz, Germany
Received 24 January 2002; accepted 20 March 2002
Abstract
To investigate structural requirements for the homophilic interaction between carbohydrates on planar model membranes,
divalent derivatives with enforced proximity between the two carbohydrate epitopes (lactose, LewisX, and sialyl LewisX) were
synthesized by use of a dimeric membrane anchor as scaffold. © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Carbohydrate–carbohydrate interaction; Lewis antigen; Neoglycolipids; Molecular recognition
tives were synthesized, which represent the smallest
possible carbohydrate cluster (Fig. 1, 1–3). Thus, the
tethering of the membrane anchor causes an enforced
proximity between the carbohydrate moieties, and the
flexibility of the carbohydrate residue is reduced to a
rotational mobility when these molecules are inserted in
planar membranes.
Considerations of the preferred conformation and
van-der-Waals radii of glycolipids reveal, that for each
hydrophilic carbohydrate head group two lipophilic
alkyl chains are required in order to be suitable con-
stituents in a physiologically relevant planar membrane
environment.7 In our case, a 2-branched fatty alkyl
residue was used to mimic the ceramide moiety of
naturally occurring glycosphingolipids.8 For the attach-
ment of two carbohydrate moieties and two 2-branched
1. Introduction
Glycolipids, found on the surface of living cells,
constitute an important class of biomolecules that are
involved in biomolecular recognition, for example in
specific cell–cell binding events.1 The amplification of
relatively weak monovalent carbohydrate–lectin affini-
ties to strong polyvalent contacts is a prerequisite of
many carbohydrate-based recognition processes.2 The
sialyl LewisX (sLeX) epitope Neu5Aca(2“3)Galb(1“
4)[Fuca(1“3)]GlcNAc is a prominent example because
of its implication in inflammation through binding to
selectins.3 The proper orientation of the sLeX glycolipid
on planar membrane surfaces leads to high local con-
centrations (lateral clusters) resulting in enhanced se-
lectin affinities.4
The polyvalent and protein-independent homophilic
carbohydrate–carbohydrate interaction is another cell-
adhesion process depending on a suitable organization
of sugar head groups, as has been recently found for
the LewisX (LeX) antigen family.5 With two covalently
tethered LeX trisaccharide epitopes, the calcium medi-
ated self-assembly of the carbohydrate moieties within
the complex could be characterized by NMR
spectroscopy.6
fatty alkyl residues, a D-threitol based scaffold was used
(Fig. 2, 4). The inherent C2 symmetry simplifies the
NMR-spectroscopic interpretation; in addition, the car-
bohydrate moieties are separated by six single bonds
that allow for considerable conformational flexibility.
Furthermore, the primary hydroxy groups enable gly-
cosylation with high yield.
2. Results and discussion
In continuation of these investigations on homophilic
carbohydrate interactions, dimeric glycolipid deriva-
The synthesis of the 2-branched alkylalcohol was
accomplished as described for homologous com-
pounds.9 Dimethyl malonate was alkylated twice with
1-decyl bromide, followed by saponification of the
methyl ester and decarboxylation (Scheme 1). The re-
* Corresponding author. Tel.: +49-7531-882538; fax: +
49-7531-883135.
E-mail address: richard.schmidt@uni-konstanz.de (R.R.
Schmidt).
0008-6215/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(02)00086-1

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C. Gege, R.R. Schmidt / Carbohydrate Research 337 (2002) 1089–1094
Fig. 1. Dimeric glycolipids 1–3 with lactose, LewisX, and sialyl LewisX head groups.
sulting acid was reduced with LiAlH4 and the formed
alcohol 58 was activated with tosyl chloride in pyridine
to afford tosylate 6.
investigated. These compounds should prove useful for
the investigation of homophilic carbohydrate interac-
tions when inserted in bicelles† as planar model mem-
branes.15 Also other cluster types are currently
generated to explore systematically the effect of multi-
valent ligand representations on biological activity.‡17
Reaction of 1,4-O-benzyl protected D-threitol deriva-
tive 710 with an excess of tosylate 6 and sodium hydride
as base in DMF–THF furnished the protected mem-
brane anchor 8 in 93% yield (Scheme 2). After hy-
drogenolytic debenzylation, the membrane anchor 4
was obtained, which served as an acceptor for the
following glycosylations.
The assembly of the target compounds is shown in
Scheme 3. Glycosylation of 4 with a threefold excess of
perbenzoylated lactosyl trichloroacetimidate 911 was
performed in the presence of TMSOTf as a catalyst
affording the dimeric glycolipid 10 in 83% yield. Exclu-
sively, the desired b-glycoside was isolated (J1a,2a 7.9
Hz). Removal of all O-benzoyl groups under Zemple´n
conditions gave the target compound 1 in 85% yield.
For the synthesis of the LeX derivative, trichloroace-
timidate 1112 was used with a threefold excess. Its
glycosidation with acceptor 4 was performed in CH2Cl2
at room temperature. To avoid the isolation of the
corresponding orthoester,13 0.4 equiv of TMSOTf and a
further 0.2 equiv of TMSOTf after 30 min were used
and the reaction time was prolonged to 4.5 h to give 12.
After removal of all O-acyl groups under Zemple´n
conditions, the target compound 2 with the desired
b-glycosidic linkage (1H NMR: J1a,2a 7.8 Hz) was iso-
lated in 69% after two steps.
Fig. 2. Structure of the required lipid anchor 4.
Scheme 1. Synthesis of 2-(decyl) dodecyl tosylate (6).
With sLeX trichloroacetimidate 13,12,13 as hexaosyl
donor, the corresponding sLeX intermediate 14 was
synthesized under the same conditions as described
above. Finally, removal of all O-acyl groups and sa-
ponification of the methyl ester the target compound 3
was isolated as triethylammonium salt after chromatog-
raphy on reversed-phase silica gel with MeOH–water–
NEt3 as eluent in 54% after two steps.
Scheme 2. Generation of lipid anchor 4.
In conclusion, an efficient method for the construc-
tion of dimeric glycolipids with lactose, LeX and sLeX,
having up to 12 sugar residues as head group has been
† For bicelle experiments, see Ref. 14.
‡ For a review on multivalent ligand design, see Ref. 16.

C. Gege, R.R. Schmidt / Carbohydrate Research 337 (2002) 1089–1094
1091
Scheme 3. Synthesis of the target molecules 1–3.
3. Experimental
2-Decyl-dodecyl-1-tosylate (6).—To a solution of 2-
decyl-dodecan-1-ol 58 (2.77 g, 8.48 mmol) in dry pyri-
dine (10 mL) was added TsCl (1.94 g, 10.2 mmol) at rt.
The mixture was stirred for 5 h, concentrated and
diluted with water and extracted with CHCl3 (3×50
mL). The organic layers were combined, dried
(Na2SO4), filtered, and concentrated. The residue,
purified by flash chromatography (25:1–19:1 petroleum
ether–EtOAc), led to 6 (3.77 g, 92%) as a colorless oil.
General methods.—Solvents were purified according
to the standard procedures. Flash chromatography was
performed on J.T. Baker Silica Gel 60 (40–63 mm) or
RP-18 Silica Gel (40 mm) at a pressure of 0.4 bar. TLC
was performed on E. Merck Silica Gel plastic plates
60F254 or E. Merck Silica Gel glass plates HPTLC
60F254, or E. Merck Silica Gel glass plates RP-18
60F254S; compounds were visualized by treatment with
a solution of (NH4)6Mo7O24·4 H2O (20 g) and Ce(SO4)2
(0.4 g) in 10% H2SO4 (400 mL) and heating at 150 °C.
Optical rotations were measured on a Perkin–Elmer
polarimeter 241 in a 1 dm cell at 22 °C. NMR measure-
ments were recorded on a Bruker AC250 Cryospec or a
Bruker DRX600 spectrometer with TMS as internal
standard. The carbohydrate monomers were assigned in
alphabetical order, beginning with the aglycon, based in
part on carbon–proton shift-correlation heteronuclear
multiple quantum coherence (HMQC). MALDI-mass
spectra were recorded on a Kratos Kompact MALDI I
instrument using a 2,5-dihydroxybenzoic acid matrix
unless otherwise stated.
1
Rf 0.67 (9:1 petroleum ether–EtOAc); H NMR (250
MHz, CDCl3): l 7.79, 7.34 (2 d, 4 H, C6H4), 3.91 (d,
Jvic 5.3 Hz, 2 H, OCH2), 2.45 (s, 3 H, CH3), 1.59–1.54
(m, 1 H, CH), 1.31–1.16 (m, 36 H, 18 CH2), 0.88 (t, 6
H, 2 CH3). MALDI-MS (positive mode, THF): 503.1
[M+Na]+.
1,4-Di-O-benzyl-2,3-di-O-(2-decyl-dodecyl)-
tol (8).—To a suspension of 6 (2.16 g, 4.50 mmol, 3
equiv) and 1,4-di-O-benzyl-
-threitol 710 (454 mg, 1.50
D-threi-
D
mmol) in dry 3:2 DMF–THF (25 mL) was added NaH
(144 mg, 6.0 mmol). The mixture was stirred overnight
under argon at 50–55 °C. Then additional 6 (750 mg,
1.56 mmol) and NaH (36 mg, 1.5 mmol) was added and

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C. Gege, R.R. Schmidt / Carbohydrate Research 337 (2002) 1089–1094
stirred again overnight. After addition of MeOH, the
mixture was concentrated, diluted with brine and ex-
tracted with CHCl3 (3×100 mL). The organic layers
were combined, dried (Na2SO4), filtered, and concen-
trated. Flash chromatography (20:1 petroleum ether–
EtOAc) of the residue furnished 8 (1.28 g, 93%) as a
colorless oil. [h]D +3.2° (c 1, CHCl3); Rf 0.54 (20:1
petroleum ether–EtOAc); 1H NMR (250 MHz,
CDCl3): l 7.32–7.27 (m, 10 H, 2 C6H5), 4.51 (s, 4 H, 2
CH2Ph), 3.68–3.48 (m, 8 H, 4 CH2), 3.36 (dd, 2 H,
CHO), 1.54 (m, 2 H, 2 CH), 1.30–1.25 (m, 72 H, 36
CH2), 0.88 (t, 12 H, 4 CH3). MALDI-MS (positive
mode, THF): 941.0 [M+Na]+, 957.0 [M+K]+.
stirred for 2 days at rt, then neutralized with Amberlite
IR-120 (H+), filtered, and concentrated. Flash chro-
matography (75:25:4–70:30:5 CHCl3–MeOH–water)
of the residue furnished 1 (60 mg, 85%) as a colorless
amorphous solid after lyophilization from water–diox-
ane. Rf 0.47 (14:6:1 CHCl3–MeOH–water, HPTLC);
1H NMR (600 MHz, 65:25:4 CDCl3–CD3OD–D2O): l
4.29 (d, J1,2 6.8 Hz, 2 H, 1b-H), 4.25 (d, J1,2 7.8 Hz, 2
H, 1a-H), 3.95 (br d, Jgem 9.0 Hz, 2 H, 1%-H), 3.83–3.33
[m, 30 H, HMQC: 3.78 (6%a-H), 3.78 (6a-H), 3.76
(4b-H), 3.71 (6%b-H), 3.61 (6b-H), 3.59 (1%-H), 3.53
(5b-H), 3.52 (4a-H), 3.48 (3a-H), 3.48 (2%-H), 3.45 (3b-
H), 3.45 (2b-H), 3.42 (3%-H), 3.34 (3%-H), 3.34 (5a-H)],
3.24 (dd, 2 H, 2a-H), 1.48 (s, 2 H, 4%-H), 1.25–1.08 (m,
72 H, 36 CH2), 0.80 (t, 12 H, 4 CH3). 13C NMR (151
MHz, 65:25:4 CDCl3–CD3OD–D2O, excerpt): 103.99
(1b-C), 103.56 (1a-C), 79.95 (2%-C), 79.76 (4a-C), 76.09
(5b-C), 75.48, 75.25, 75.21 (3a-C, 5a-C, 3%-C), 73.77
(3b-C), 73.55 (2a-C), 71.66 (2b-C), 69.43 (4b-C), 68.91
(1%-C), 61.78 (6b-C), 61.30 (6a-C). MALDI-MS (posi-
tive mode, CHCl3–MeOH): 1410.6 [M+Na]+, 1427.6
[M+K]+.
2,3-Di-O-(2-decyl-dodecyl)- -threitol (4).—To a so-
D
lution of 8 (1.21 g, 1.32 mmol) in EtOAc (40 mL) was
added AcOH (3 drops) and 10% Pd–C (180 mg).
Hydrogenolysis was performed at atmospheric pressure
overnight and then the mixture was filtered through
Celite, washed and concentrated. Flash chromatogra-
phy (9:1–7:1 petroleum ether–EtOAc) of the residue
led to 4 (763 mg, 72%) as a colorless oil. [h]D +0.8° (c
1
1, CHCl3); Rf 0.16 (9:1 petroleum ether–EtOAc); H
NMR (250 MHz, CDCl3): l 3.82–3.44 (m, 10 H, 2
CHO, 4 CH2), 2.36 (s, 2 H, 2 OH), 1.54 (m, 2 H, 2
CH), 1.34–1.26 (m, 72 H, 36 CH2), 0.88 (t, 12 H, 4
CH3). MALDI-MS (positive mode, THF): 761.4 [M+
Na]+, 777.3 [M+K]+.
1,4-Di-O-[(2,4,6-tri-O-acetyl-i-
(1“4)-[(2,3,4-tri-O-acetyl-h- -fucopyranosyl)-(1“3)]-
(2-acetamido-6-O-acetyl-2-deoxy-i- -glucopyranosyl)-
(1“3)-(2,4,6-tri-O-acetyl-i- -galactopyranosyl)-(1“4)-
3,6-di-O-acetyl-2-O-benzoyl-i- -glucopyranosyl]-2,3-
diO-(2-decyl-dodecyl)- -threitol (12).—A solution of
D-galactopyranosyl)-
L
D
D
D
1,4-Di-O-[(2,3,4,6-tetra-O-benzoyl-i-
nosyl)-(1“4)-2,3,6-tri-O-benzoyl-i- -glucopyranosyl]-
2,3-di-O-(2-decyl-dodecyl)- -threitol (10).—A solution
of O-(2,3,4,6-tetra-O-benzoyl-b- -galactopyranosyl)-
(1“4)-2,3,6-tri-O-benzoyl-a/b- -glucopyranosyl tri-
D
-galactopyra-
D
D
LeX trichloroacetimidate 1112 (209 mg, 124 mmol, 3
equiv) and 4 (31.0 mg, 41.3 mmol) in dry CH2Cl2 (5 mL)
was stirred with molecular sieves AW-300 for 30 min.
Then TMSOTf (3.0 mL, 17 mmol, 0.4 equiv) was added
under argon at rt and after 30 min again TMSOTf (1.5
mL, 0.2 equiv). After further 4 h, the solution was
neutralized with NEt3, filtrated, and concentrated.
Flash chromatography (2:1 toluene–acetone) of the
residue gave 12 (135 mg, 88%) as a pale yellow foam. Rf
0.33 (3:2 toluene–acetone, HPTLC); 1H NMR (600
MHz, CDCl3): l 7.95–7.43 (m, 10 H, 2 C6H5), 5.41–
3.06 [m, 78 H, HMQC: 5.40 (4e-H), 5.36 (4d-H), 5.32
(1d-H), 5.32 (3a-H), 5.30 (4b-H), 5.18 (3d-H), 5.10
(2a-H), 5.09 (2e-H), 5.01 (3e-H), 4.96 (6%c-H), 4.96
(2b-H), 4.95 (5d-H), 4.95 (2d-H), 4.95 (1c-H), 4.60
(1e-H), 4.41 (6%a-H), 4.39 (6%e-H), 4.39 (1b-H), 4.32
(1a-H), 4.30 (3c-H), 4.20 (6e-H), 4.12 (6a-H), 4.10
(6%b-H), 4.03 (6b-H), 3.93 (6c-H), 3.89 (1%-CHH), 3.87
(5e-H), 3.80 (4c-H), 3.77 (4a-H), 3.75 (5b-H), 3.70
(3b-H), 3.52 (5a-H), 3.42 (5c-H), 3.35 (1%-CHH), 3.35
(2%-H), 3.14, 3.07 (3%-CH2), 3.05 (2c-H), NcH], 2.19–
1.90 (m, 84 H, 28 COCH3), 1.63 (s, 2 H, 4%-H), 1.32–
0.92 (m, 78 H, 36 CH2, 6d-CH3), 0.89 (t, 12 H, 4 CH3).
MALDI-MS (positive mode, THF): 3734.9 [M+Na]+,
3750.2 [M+K]+.
D
D
D
chloroacetimidate (9)11 (234 mg, 193 mmol, 3 equiv) and
4 (47.6 mg, 64.3 mmol) in dry CH2Cl2 (3 mL) was
stirred with molecular sieves AW-300 for 30 min. Then
TMSOTf (3.5 mL, 19 mmol, 0.3 equiv) was added under
argon at rt. After 1 h the solution was neutralized with
NEt3, filtrated, and concentrated. Flash chromatogra-
phy (14:1 toluene–EtOAc) of the residue gave 10 (153
mg, 83%) as a colorless foam. [h]D +32.3° (c 1,
1
CHCl3); Rf 0.37 (12:1 toluene–EtOAc); H NMR (600
MHz, CDCl3): l 8.00–7.12 (m, 70 H, 14 C6H5), 5.73–
5.70 (m, 4 H, 2b-H, 4b-H), 5.64 (d, J2,3=J3,4 9.5 Hz, 2
H, 3a-H), 5.38–5.34 (m, 4 H, 2a-H, 3b-H), 4.81 (d, J1,2
7.9 Hz, 2 H, 1b-H), 4.49–4.42 (m, 4 H, 6a-H, 6%a-H),
4.31 (d, J1,2 7.9 Hz, 2 H, 1a-H), 4.15 (dd, J3,4=J4,5 9.4
Hz, 2 H, 4a-H), 3.85–3.83 (m, 4 H, 2%-H, 5b-H), 3.67
(m, 4 H, 6b-H, 6%b-H), 3.54 (m, 2 H, 5a-H), 3.31 (m, 4
H, 1%-CH2), 3.12–3.03 (m, 4 H, 3%-CH2), 1.58 (s, 2 H,
4%-H), 1.30–0.96 (m, 72 H, 36 CH2), 0.88 (t, 12 H, 4
CH3). Anal. Calcd for C170H194O38·H2O (2863.40): C,
71.31; H, 6.90. Found: C, 71.35; H, 6.92.
1,4-Di-O-[(i-
D
-galactopyranosyl)-(1“4)-i-D-gluco-
pyranosyl]-2,3-di-O-(2-decyl-dodecyl)-
To a solution of 10 (145 mg, 50.6 mmol) in dry MeOH
(10 mL) was added NaOMe (10 mg). The mixture was
D
-threitol (1).—
1,4-Di-O-[(i-
pyranosyl) - (1“3)] - (2 - acetamido - 2 - deoxy-i-
pyranosyl)-(1“3)-(i- -galactopyranosyl)-(1“4)-i-D-
D
-galactopyranosyl)-(1“4)-[(h-
L
-fuco-
D-gluco-
D

C. Gege, R.R. Schmidt / Carbohydrate Research 337 (2002) 1089–1094
1093
glucopyranosyl]-2,3-di-O-(2-decyl-dodecyl)-
D
-threitol
H), 3.88 (1%-CHH), 3.87 (4c-H), 3.86 (COOCH3), 3.84
(5e-H), 3.77 (4a-H), 3.73 (5b-H), 3.69 (3b-H), 3.63
(6f-H), 3.51 (5a-H), 3.45 (5c-H), 3.35 (2%-H), 3.34 (1%-
CHH), 3.18 (2c-H), 3.14, 3.07 (3%-CH2)], 2.58 (dd, J3,4
4.2, Jgem 12.4 Hz, 2 H, 3f-He), 2.20–1.85 (m, 108 H, 36
COCH3), 1.68 (t, J3,4=Jgem 12.3 Hz, 2 H, 3f-Ha), 1.62
(s, 2 H, 4%-H), 1.32–0.94 (m, 78 H, 36 CH2, 6d-CH3),
0.89 (t, 12 H, 4 CH3). 13C NMR (151 MHz, CDCl3,
excerpt): l 100.8 (1a-C), 100.7 (1b-C), 99.9 (1e-C), 99.4,
(1c-C), 95.3 (1d-C), 78.6 (2%-C), 76.0 (3b-C), 75.6 (4a-
C), 74.4 (3%-C), 74.3 (4c-C), 73.1 (5c-C), 72.8 (5a-C),
72.5 (3a-C), 72.3 (3c-C), 71.9 (6f-C), 71.8 (2a-C), 71.6
(4d-C), 71.4 (3e-C), 71.2 (2b-C), 71.2 (5b-C), 70.9 (5e-
C), 70.1 (1%-C), 69.8 (2e-C), 69.4 (4f-C), 69.0 (4b-C),
68.9 (2d-C), 68.0 (3d-C), 67.6 (8f-C), 67.4 (4e-C), 66.6
(7f-C), 64.1 (5d-C), 62.1 (6a-C), 61.7 (9f-C), 61.5 (6b-
C), 61.4 (6e-C), 60.9 (6b-C), 58.5 (2cC), 53.2 (OCH3),
49.1 (5f-C), 38.3 (4%-C), 37.4 (3f-C), 15.8 (6d-C).
MALDI-MS (positive mode, THF): 4598.7 [M+Na]+,
4613.1 [M+K]+. Anal. Calcd for C214H314N4O102
(4574.70): C, 56.19; H, 6.92; N, 1.22. Found: C, 56.20;
H, 6.84; N, 0.85.
(2).—To a solution of 12 (130 mg, 35.0 mmol) in dry
MeOH (40 mL) was added NaOMe (40 mg). The
mixture was stirred for 3 days at rt, then neutralized
with Amberlite IR-120 (H+), filtered, and adsorbed on
RP-18 Silica Gel. Flash chromatography with RP-18
Silica Gel (2:1–5:1–1:0 MeOH–water) furnished 2
(57.9 mg, 78%) as a colorless amorphous solid after
1
lyophilization from water. Rf 0.36 (MeOH, RP-18); H
NMR (600 MHz, CD3OD): l 5.05 (d, J1,2 3.8 Hz, 2 H,
1d-H), 4.82 (5d-H in solvent signal), 4.70 (d, J1,2 7.9 Hz,
2 H, 1c-H), 4.43 (d, J1,2 7.5 Hz, 2 H, 1e-H), 4.37 (d, J1,2
7.7 Hz, 2 H, 1b-H), 4.32 (d, J1,2 7.8 Hz, 2 H, 1a-H),
4.05–3.23 [m, 54 H, HMQC: 4.05 (4b-H), 3.95 (6%c-H),
3.91 (3c-H), 3.90 (2c-H), 3.90 (6c-H), 3.89 (6%a-H), 3.87
(4c-H), 3.86 (3d-H), 3.84 (6a-H), 3.79 (4e-H), 3.78
(6%b-H), 3.76 (6%e-H), 3.71 (4d-H), 3.67 (6b-H), 3.66
(6e-H), 3.64 (2d-H), 3.62 (2b-H), 3.58 (5b-H), 3.57
(4a-H), 3.53 (3b-H), 3.52 (3a-H), 3.50 (2e-H), 3.45
(5e-H), 3.45 (3e-H), 3.43 (5c-H), 3.40 (5a-H), 3.26 (2a-
H)], 1.97 (s, 6 H, COCH3), 1.55 (m, 2 H, 4%-H),
1.38–1.28 (m, 72 H, 36 CH2), 1.17 (d, J5,6 6.5 Hz, 6 H,
6d-CH3), 0.90 (t, 12 H, 4 CH3). MALDI-MS (positive
mode, MeOH): 2436.4 [M+Na]+.
1,4 - Di - O - [(triethylammonium - 5 - acetamido - 3,5 - di-
deoxy-
(2“3)-(i-
nosyl)-(1“3)]-(2-acetamido-2-deoxy-i-
nosyl) - (1“3) - (i - - galactopyranosyl) - (1“4) - i -
glucopyranosyl]-2,3-di-O-(2-decyl-dodecyl)- -threitol
D
-glycero-h-
D
-galacto-2-nonulopyranosylonate)-
-fucopyra-
-glucopyra-
D
-galactopyranosyl)-(1“4)-[(h-
L
1,4-Di-O-[(methyl-5-acetamido-4,7,8,9-tetra-O-ace-
D
tyl-3,5-dideoxy-
osylonate)-(2“3)-(2,4,6-tri-O-acetyl-i-
nosyl) - (1“4) - [(2,3,4 - tri - O-acetyl-h- -fucopyranosyl)-
(1“3)]-(2-acetamido-6-O-acetyl-2-deoxy-i- -gluco-
pyranosyl)-(1“3)-(2,4,6-tri-O-acetyl-i- -galactopyra-
nosyl)-(1“4)-3,6-di-O-acetyl-2-O-benzoyl-i- -gluco-
pyranosyl]-2,3-di-O-(2-decyl-dodecyl)- -threitol (14).—
D
-glycero-h-
D
-galacto-2-nonulopyran-
D
D-
D
-galactopyra-
D
L
(3).—To a solution of 14 (159 mg, 34.8 mmol) in dry
MeOH (40 mL) was added NaOMe (80 mg). The
mixture was stirred for 2 days at rt, then water (0.5 mL)
was added and stirred for 3 h. After neutralization with
Amberlite IR-120 (H+), the mixture was filtered and
adsorbed on RP-18 Silica Gel. Flash chromatography
with RP-18 Silica Gel (5:1–8:1–1:0 MeOH–water+
0.5% NEt3) afforded 1 (91.4 mg, 82%) as a colorless
amorphous solid after lyophilization from water. Rf
D
D
D
D
A solution of sLeX trichloroacetimidate 1313 (346 mg,
165 mmol, 3 equiv) and 4 (40.7 mg, 55.0 mmol) in dry
CH2Cl2 (5 mL) was stirred with molecular sieves AW-
300 for 30 min. Then TMSOTf (4.0 mL, 22 mmol, 0.4
equiv) was added under argon at rt and after 30 min
again TMSOTf (2.0 mL, 0.2 equiv). After further 4.5 h,
the solution was neutralized with NEt3, filtrated, and
concentrated. Flash chromatography (20:1–15:1
CHCl3–MeOH) of the residue gave 14 (166 mg, 66%)
as a colorless foam. [h]D −19.5° (c 1, CHCl3); Rf 0.26
1
0.71 (MeOH, RP-18); H NMR (600 MHz, CD3OD): l
5.04 (d, J1,2 3.7 Hz, 2 H, 1d-H), 4.82 (5d-H in solvent
signal), 4.68 (d, J1,2 7.7 Hz, 2 H, 1c-H), 4.50 (d, J1,2 7.7
Hz, 2 H, 1e-H), 4.37 (d, J1,2 7.7 Hz, 2 H, 1b-H), 4.32 (d,
J1,2 7.8 Hz, 2 H, 1a-H), 4.05–3.25 [m, 68 H, HMQC:
4.05 (4b-H), 4.03 (3e-H), 4.02 (6%c-H), 3.93 (2c-H), 3.91
(3c-H), 3.89 (6a-H), 3.87 (4e-H), 3.88 (6c-H), 3.85 (4c-
H), 3.84 (9%f-H), 3.84 (6a-H), 3.77 (6%b-H), 3.75 (6%e-H),
3.71 (4d-H), 3.70 (5f-H), 3.70 (4f-H), 3.69 (6f-H), 3.69
(6b-H), 3.64 (6e-H), 3.63 (7f-H), 3.62 (2d-H), 3.61
(2b-H), 3.59 (9f-H), 3.59 (5b-H), 3.57 (3d-H), 3.56
(4a-H), 3.54 (3b-H), 3.53 (2e-H), 3.51 (3a-H), 3.45
(8f-H), 3.45 (5e-H), 3.43 (5c-H), 3.39 (5a-H), 3.25 (2a-
H)], 3.20 (q, 12 H, N(CH2Me)3), 2.87 (dd, 2 H, 3f-He),
2.00, 1.97 (2 s, 12 H, 2 COCH3), 1.71 (t, 2 H, 3f-Ha),
1.55 (m, 2 H, 4%-H), 1.37–1.28 (m, 90 H, 18 CH2,
N(CH2CH3)3), 1.15 (d, J5,6 6.5 Hz, 6 H, 6d-CH3), 0.90
(t, 12 H, 2 CH3). MALDI-MS (negative mode, matrix
4-nitroaniline, MeOH): 2990 [M−NEt3−HNEt3]−,
3012 [M−2HNEt3+Na]−.
1
(3:2 toluene–acetone, HPTLC); H NMR (600 MHz,
CDCl3): l 8.00–7.42 (m, 10 H, 2 C6H5), 5.33–5.31 [m,
12 H, HMQC: 5.51 (8f-H), 5.44 (7f-H), 5.33 (1d-H),
5.33 (4b-H), 5.32 (NcH), 5.31 (4d-H)], 5.23 (dd, J2,3
=
J3,4 9.5 Hz, 2 H, 3a-H), 5.20 (dd, J2,3 10.9, J3,4 3.1 Hz,
2 H, 3d-H), 5.10 (dd, J1,2 8.2, J2,3 9.5 Hz, 2 H, 2a-H),
5.02–4.77 [m, 20 H, HMQC: 5.00 (5d-H), 4.98 (2b-H),
4.95 (4e-H), 4.95 (2d-H), 4.90 (1c-H), 4.89 (2e-H), 4.88
(4f-H), 4.81 (6%c-H), 4.77 (1e-H), NfH], 4.52 (dd, J2,3
10.1, J3,4 3.2 Hz, 2 H, 3e-H), 4.43–4.37 [m, 4 H,
HMQC: 4.42 (6%a-H), 4.38 (6%e-H)], 4.33 (d, J1,2 7.9 Hz,
2 H, 1a-H), 4.31 (d, J1,2 8.0 Hz, 2 H, 1b-H), 4.43–3.07
[m, 50 H, HMQC: 4.25 (9%f-H) 4.22 (3c-H), 4.22 (6e-H),
4.13 (6a-H), 4.08 (9f-H), 4.03 (5f-H), 4.00 (6b-H, 6%b-

1094
C. Gege, R.R. Schmidt / Carbohydrate Research 337 (2002) 1089–1094
(c) de la Fuente, J. M.; Barrientos, A. G.; Rojas, T. C.;
Acknowledgements
Rojo, J.; Can˜ada, J.; Ferna´ndez, A.; Penade´s, S. Angew.
Chem. 2001, 113, 2317–2321; Angew. Chem. Int. Ed. 2001,
40, 2258–2261.
This work was supported by the Deutsche
Forschungsgemeinschaft and the Fonds der Chemis-
chen Industrie. We are grateful to Professor Armin
Geyer (University Regensburg) for the structural as-
signments.
6. Geyer, A.; Gege, C.; Schmidt, R. R. Angew. Chem. 2000,
112, 3381–3385; Angew. Chem. Int. Ed. 2000, 39, 3246–
3249.
7. Schmidt R. R.; Jankowski K. Liebigs Ann. 1996, 867–879.
8. Hasegawa A.; Suzuki N.; Ishida H.; Kiso M. J. Carbohydr.
Chem. 1996, 15, 623–637.
9. Garrigues E.; Souchard J.-P.; Nepveu F. Tetrahedron Lett.
1998, 39, 4489–4492.
10. Dehmlow E. V.; Sauerbier C. Liebigs Ann. Chem. 1989,
181–185.
References
11. Boons G. J. P. H.; van Delft F. L.; van der Klein P. A.
M.; van der Marel G. A.; van Boom J. H. Tetrahedron
1992, 48, 885–904.
12. Gege, C.; Geyer, A.; Schmidt, R. R. unpublished results.
13. Gege C.; Oscarson S.; Schmidt R. R. Tetrahedron Lett.
2001, 42, 377–380.
14. (a) Sanders C. R., II; Hare B. J.; Howard K. P.; Prestegard
J. H. Prog. NMR Spectrosc. 1994, 26, 421–444;
(b) Prestegard J. H. Nature, Struct. Biol. NMR II Suppl.
1998, 5, 517–522;
(c) Bolon P. J.; Prestegard J. H. J. Am. Chem. Soc. 1998,
120, 9366–9367.
15. Gege C.; Arsic M.; Schmidt R. R.; Geyer A. In Proceedings
of ECSOC-4. http://www.mdpi.org/ecsoc-4.htm; Wirth T.;
Kappe C. O.; Felder E.; Diederichsen U.; Lin S.-K., Eds.;
MDPI: Basel, 2000; p C0014.
1. Varki A.; Cummings R.; Esko J.; Freeze H.; Hart G.;
Marth J. Essentials of Glycobiology; Cold Spring Harbor
Laboratory Press: New York, 1999.
2. (a) Ernst B.; Hart G. W.; Sinay¨ P. Carbohydrates in
Chemistry and Biology; Wiley VCH: Weinheim, 2000;
(b) Mammen, M.; Choi, S. -K.; Whitesides, G. M. Angew.
Chem. 1998, 110, 2908–2953; Angew. Chem. Int., Ed. Engl.
1998, 37, 2754–2794.
3. Simanek E. E.; McGarvey G. J.; Jablonowski J. A.; Wong
C.-H. Chem. Re6. 1998, 98, 833–862.
4. Vogel J.; Bendas G.; Bakowsky U.; Hummel G.; Schmidt
R. R.; Kettmann U.; Rothe U. Biochim. Biophys. Acta
1998, 1372, 205–215.
5. (a) Hakomori S.; Handa K.; Iwabuchi K.; Yamamura S.;
Prinetti A. Glycobiology 1998, 8, xi–xix;
(b) Geyer, A.; Gege, C.; Schmidt, R. R. Angew. Chem.
1999, 111, 1569–1571; Angew. Chem. Int. Ed. 1999, 38,
1466–1468;
16. Kiessling L. L.; Strong L. E.; Gestwicki J. E. Annu. Rep.
Med. Chem. 2000, 35, 321–330.
17. Cong, Y.; Gege, C.; Schmidt, R. R. unpublished results.