Synthesis of a potential 10E4 tetrasaccharide antigen involved in scrapie pathogenesis

Article abstract of DOI:10.1002/hlca.200690234

To test the hypothesis that tetrasaccharide 3 is involved in scrapie pathogenesis, tetrasaccharide derivative 32 functionalized with an amine linker at the reducing end was synthesized. A (2 + 2) glycosylation approach was chosen to furnish the target com

Full text of DOI:10.1002/hlca.200690234

Helvetica Chimica Acta – Vol. 89 (2006)2591
Synthesis of a Potential 10E4 Tetrasaccharide Antigen Involved in Scrapie
Pathogenesis
by Pascal Bindschädler, Christian Noti, Eva Castagnetti, and Peter H.Seeberger *
Laboratory for Organic Chemistry, Swiss Federal Institute of Technology (ETH)Zürich,
Wolfgang-Pauli-Strasse 10, HCIF315, CH-8093 Zürich
(fax: +41446331235; e-mail: seeberger@org.chem.ethz.ch)
To test the hypothesis that tetrasaccharide 3 is involved in scrapie pathogenesis, tetrasaccharide
derivative 32 functionalized with an amine linker at the reducing end was synthesized. A (2+2)glyco-
sylation approach was chosen to furnish the target compound in fully protected form. To investigate its
biological role, tetrasaccharide 32 was further functionalized to the corresponding thiol 33 using Trautꢀs
reagent. During the course of the synthesis, the N,N-diacetyl protecting group proved surprisingly labile
to radical and acidic conditions.
Introduction. – Heparin and heparan sulfate are the most complex glucosaminogly-
cans (GAGs), a class of protein-conjugated polysaccharides found in the extracellular
matrix of all mammalian cells. GAGs are involved in important biological functions by
binding to different growth factors, enzymes, morphogens, cell-adhesion molecules, and
cytokines [1]. Many aspects of GAG chemistry [2], biology [1d][3], and structure-activ-
ity relationship (SAR)[4] have been reviewed recently.
The unbranched, highly sulfated polysaccharide heparin is composed of disacchar-
ide units consisting of a uronic acid (UA)1,4-linked to a D-glucosamine (GlcN)unit. L-
Iduronic acid (IdoA, 90%)predominates its C(5)-epimer D-glucuronic acid (GlcA,
10%). Typically, a heparin disaccharide contains three sulfate groups: O-sulfation at
the OH group at C(2)of the uronic acids, at the OH group at C(3)and/or C(6)of
the amino sugar. Additionally, the glucosamine unit can be N-sulfated, N-acetylated,
or, less frequently, remain unmodified. Heparan sulfate is more heterogeneous than
heparin as it contains more N-acetyl D-glucosamines (GlcNAc)and glucuronic acids,
and less O-sulfates [5].
Recent evidence points to the possible involvement of a specific heparan sulfate
carbohydrate sequence in scrapie pathogenesis [6]. Scrapie is a transmissible neurode-
generative disease characterized by the deposition of PrPSc, a misfolded, abnormally
protease-resistant isoform of the parent prion protein PrPC [7]. Considerable progress
has been made toward understanding the molecular and cellular biology of prions;
however, precise details of the conversion mechanism to the disease-associated form
remain elusive [8]. It has been shown that the carbohydrate antigen on heparan sulfate
recognized by the monoclonal antibody 10E4 is uniquely co-distributed with the abnor-
mal prion protein PrPSc already in the earliest detectable brain lesions of scrapie-
infected mice [6]. To elucidate the role of the 10E4 antigen in scrapie pathogenesis,
it is crucial to determine its exact structure. Since biological sources do not yield suffi-
ꢁ 2006 Verlag Helvetica Chimica Acta AG, Zürich

2592
Helvetica Chimica Acta – Vol. 89 (2006)
cient amounts of clean material to establish the structure of the 10E4 antigen or to
determine its interactions with PrPSc on the molecular level, chemical synthesis serves
as a last resort.
A tetrasaccharide recognized by antibody 10E4 has been isolated and was exam-
ined by electrospray mass spectrometry (ESI-MS)[9]. The tetrasaccharide sequence
was found to contain a unique non-sulfated motif that includes a glucosamine with a
free amine in the sequence, UA-(1 ! 4)-GlcN-a-(1 ! 4)-UA-(1 ! 4)-GlcNAc. Tetra-
saccharides
1
(GlcA-b-(1 ! 4)-GlcN-a-(1 ! 4)-IdoA-a-(1 ! 4)-GlcNAc) and
2
(GlcA-b-(1 ! 4)-GlcN-a-(1 ! 4)-GlcA-b-(1 ! 4)-GlcNAc) were postulated to be
the most likely structures of the 10E4 antigen (Fig. 1).
Fig. 1. Structures of tetrasaccharides 1–3
Both, 1 and 2 were synthesized and tested by BonnaffØ, Feizi, and co-workers [10]
using the neoglycolipid (NGL)technology for oligosaccharide presentation and ligand
discovery [11]. 10E4 bound neither of the two structures. Therefore, tetrasaccharide 3
(IdoA-a-(1 ! 4)-GlcN-a-(1 ! 4)-GlcA-b-(1 ! 4)-GlcNAc; Fig. 1)was identified as
candidate antigen of 10E4 [9][12]. Herein, we describe the first total synthesis of a
derivative of tetrasaccharide 3.
Results and Discussion. – 1. Synthesis of Tetrasaccharide 4. Handling oligosacchar-
ides with a free reducing end can be problematic due to their aldehyde-like reactivity.
Therefore, tetrasaccharide 4 (Scheme 1), with a functionalized linker [13] attached via
an a-linkage1)to the reducing end, was chosen as synthetic target. Attachment of 4 to
1)Tetrasaccharide 3 is a-linked to the subsequent uronic acid.

Helvetica Chimica Acta – Vol. 89 (2006)2593
Scheme 1. Retrosynthetic Analysis of Tetrasaccharide 4
microarrays can be accomplished via the free sulfanyl function of the linker by conju-
gation to maleimide-derivatized structures [14].
Retrosynthetic analysis of tetrasaccharide 4 reveals a convergent (2+2)approach
to provide the fully protected precursor 5 (Scheme 1). Tetrasaccharide 5 would be con-
verted to 4 by radical-transformation of the trichloroacetyl (TCA)group to an acetate
group using Bu3SnH and catalytic amounts of 2,2’-azobis[isobutyronitrile] (AIBN), fol-
A
lowed by global deprotection. Disaccharide 6 had previously been prepared in our lab-
oratory [15]. Thus, initial efforts focused on the synthesis of reducing end disaccharide 7
and two monosaccharides, thioglycoside 8 and the TCA-protected glucosamine deriv-
ative 9 (Scheme 1).
Placement of the sulfanyl-linker via an a-linkage to the reducing-end monosacchar-
ide necessitated azido-glucose trichloroacetimidate 10 [16] as starting point for cou-

2594
Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 2
a) HÀ(OCH2CH2)3ÀSBn, TMSOTf, CH2Cl2, r.t.; 83% (a/b 0.57:0.43). b)1. Me
TCA-Cl, Et3N, CH2Cl2, 08 to r.t.; 89% (12a: 50%, 12b: 39%). c)TES, TFAA, TFA, CH 2Cl2, 08 to
158; 67%.
3P, THF, H2O, r.t.; 2.
AHCTREUNG
pling to 2-{2-[2-(benzylsulfanyl)ethoxy]ethoxy}ethanol [13][17] (Scheme 2). The trime-
thylsilyl triflate (TMSOTf)-catalyzed glycosylation furnished 11 in 83% yield. How-
ever, the 0.57:0.43 mixture of a/b-isomers (determined by 1H-NMR)were inseparable
by flash chromatography (FC). Azido-glucose 11 was converted to the TCA-protected
glucosamine 12 (89%)by reduction of the azido derivative with Me 3P to the amine, fol-
U
lowed by acylation with TCA-Cl. At this stage, the two anomers were readily separated
by FC. The desired a-isomer was converted to 9 (67%)by regioselective opening of the
benzylidine group, using trifluoroacetic acid (TFA), trifluoroacetic anhydride (TFAA),
and triethylsilane (Et3SiH, TES).
T
The OH group at C(4)of glucuronic acid 13 [18] was reacted with levulinic acid
(LevOH), diisopropylcarbodiimide (DIPC), and 4-(dimethylamino)pyridine
(DMAP)to yield 89% of fully protected thioglycoside 8 (Scheme 3). Alternatively,
13 was treated with [(9H-fluoren-9-yl)methoxy]carbonyl chloride (Fmoc-Cl) in pyri-
dine to yield building block 14 (80%)that is potentially useful for the automated syn-
thesis of oligosaccharides [19].
Scheme 3
a)LevOH, DIPC, DMAP, CH Cl2, r.t.; 89%. b)Fmoc-Cl, pyridine, 0 8 to r.t.; 80%.
2
Crystal structures of 8 and 14 (Fig. 2)confirmed the absolute configuration of these
compounds and offered insights into the conformational constraints of such systems.
These are two of the rare X-ray crystal structures of thioglycoside building blocks [20].
Union of glucosamine 9 and glucuronic acid 8 to obtain disaccharide 15 presented a
challenge (Scheme 4). 1-(Phenylsulfinyl)piperidine (BSP, ꢂbenzenesulfinyl piperidineꢀ)

Helvetica Chimica Acta – Vol. 89 (2006)2595
Fig. 2. ORTEP [21] Representation of the crystal structure of Fmoc-protected thioglycoside building
block 14
and triflic anhydride (Tf2O)were used to pre-activate thioglycoside 8 [22]. To avoid
A
ortho-ester formation, no base was added to the reaction mixture2). The reaction did
not proceed satisfactorily. Despite the participating BzO group at C(2)of 8, the reac-
tion did not selectively afford disaccharide 15. The thioether moiety of 9 is believed
to coordinate to the anomeric center and thereby diminish b-selectivity. A complex
mixture of products had to be purified by FC and recycling preparative HPLC to afford
15 in 31% yield. Removal of the Lev protecting group with in situ generated hydrazine
acetate proceeded in 97% yield to give 7 (Scheme 4). With compound 7 in hand, assem-
bly of the fully protected tetrasaccharide 5 was attempted by reaction of 7 with trichloro-
acetimidate 6. Unfortunately, the formation of the tetrasaccharide 5 was never ach-
ieved in acceptable yield or purity (Scheme 4).
Rearranged disaccharide 16 and silylated building block 17 were obtained as main
products (Fig. 3), presumably due to the highly disarmed3)nature of building block 7
and complications caused by the thioether. Unreacted 7 was also isolated.
Due to these major difficulties in both coupling steps, we decided to modify our
strategy and introduce the thiol at the tetrasaccharide stage – following the two crucial
coupling steps.
2. Synthesis of Tetrasaccharide 32 Using a Pentenyl Linker. Monosaccharide 18
(Scheme 5)was chosen to replace 9 at the reducing end of the tetrasaccharide. The
N,N-diacetyl protecting group [24] was selected for evaluation as amine-protecting
group. The diacetyl derivative can be readily converted to the N-monoacetate by
hydrolysis at the end of a synthesis. Masking of GlcNAc as GlcNAc2 or GlcN(TCA)
2)Usually, a base such as 2,4,6-tri-( tert-butyl)pyrimidine (TTBP) is used with Tf2
to quench TfOH that is generated in the course of the reaction [22].
3)For
Fraser-Reidꢀs armed–disarmed approach, see [23].
A

2596
Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 4
a)BSP, Tf
ACHTREUNG
Fig. 3. Structures of rearranged glycosyl trichloroacetimidate 16 and silylated building block 17
is generally recommended, since GlcNAc derivatives are poor nucleophiles in glycosy-
lation reactions [24d][25]4); even an inhibitory effect of a remote N-Ac group upon tri-
chlororoacetimidate-mediated coupling was observed when the GlcNAc was present at
the reducing end of a disaccharide [27]. The synthesis of 18 started with a Fischer gly-
cosylation [28] of N-acetyl-D-glucosamine 19 in pent-4-en-1-ol, followed by installation
of the 4,6-benzylidene acetal, and furnished selectively the desired a-glucosamine
derivative 20 (65%). O-Benzylation of the remaining free OH group to afford 21
was achieved in 92% yield using BnBr, BaOH, and BaO [29]5). Microwave irradiation
at 858 using AcCl and diisopropylethylamine (DIPEA)in MeCN/CH 2Cl2 3 :2 (v/v)was
used to form the N,N-diacetyl derivative 22 in 93% yield. Regioselective opening of the
benzylidene group, using TFA, TFAA, and TES, afforded 18 (67%). The reaction con-
4)However, there were also numerous successful glycosylation reactions performed on N-Ac-contain-
ing acceptors, see, e.g., [26].
5)Other methods such as BnBr/NaH or BnBr/Ag 2O did not give satisfactory results.

Helvetica Chimica Acta – Vol. 89 (2006)2597
Scheme 5
a)1. Pent-4-en-1-ol, TsOH·H 2O, 908; 2. PhCH(OMe)2, TsOH·H2O, MeCN, r.t.; 65%. b)BaO,
BaOH·8H2O, BnBr, DMF, r.t.; 92%. c)AcCl, DIPEA, CH 2Cl2/MeCN 3 :2 (v/v) , 858 (microwave,
80 W); 93%. d)TES, TFAA, TFA, CH Cl2, 08 to 148; 67%.
2
ditions had to be carefully adjusted, as longer reaction times and especially higher tem-
perature (>158)led to a dramatic decrease in yield due to partial cleavage of one of the
N-acetates.
Since the BSP/Tf2O system that was used for the condensation of 8 and 9 to form
A
disaccharide 15 is incompatible with the pent-4-enyl moiety of 18, we evaluated
MeOTf as an activator for 8. Coupling reactions with differently activatable building
blocks were also tested for their ability to furnish the desired disaccharide 23. We
first converted thioglycoside 8 to the corresponding trichloroacetimidate 24, sulfoxide
25, and phosphate 266)by reacting 8 with N-iodosuccinimide (NIS)and Tf 2
O, followed
A
by CCl3CN and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)(for 24; 57%), 3-chloroper-
oxybenzoic acid (m-CPBA)(for 25; 90%)7), or NIS and dibutylphosphoric acid (for
26), respectively. Sulfoxide 25 was obtained as a mixture of epimers (Scheme 6). The
molecular structure of the (S)-epimer that crystallized selectively was elucidated
(Fig. 4). It is one of the rare X-ray crystal structures of monosaccharides building blocks
containing a sulfoxide leaving group [30].
Scheme 6
a)1. NIS, Tf
ACHTREUNG
Disaccharide 23 was obtained in poor yield (28%), following activation of 8 with
MeOTf and reaction with 18, and could not be purified from the by-products (Table
1). Partial cleavage of one of the two N-acetyl groups and methylation of the OH
6)Synthesis and coupling of 26 are not shown.
7)Sulfone 27 (8%)was obtained as a side-product.

2598
Helvetica Chimica Acta – Vol. 89 (2006)
Fig. 4. ORTEP [21] Representation of the crystal structure of Lev-protected sulfoxide building block
25 ((S)-epimer)
Table 1. Coupling Reactions of 8, 24, 26, or 25 with 18 to formDisaccharide 23
X
18 [equiv.]
i)Yield [%]
28
8 (R=SPh, R1 =H)0.5
M,erO.t.Tf (5 equiv.)
)
a
24 (R=H, R1 =OC(NH)CCl3)0.8
26 (R=H, R1 =OP(O)(OBn)2)0.8
25 (R=S(O)Ph, R1 =H)0.8
TMSOTf (0.2 eq, u0iv.)
TMSOTf (1 eq,uiv.)
8
19
traces
32
À508 to r.t.
Tf
A
a)Contains traces of impurities (by 1H-NMR).
group at C(4)of 18 occurred. The use of trichloroacetimidate building block 24 and cat-
alytic amounts of TMSOTf afforded 23 in 19% yield. The reaction of phosphate 26 with
stoichiometric amounts of TMSOTf was very slow, and only traces of disaccharide 23
were isolated. Finally, coupling of sulfoxide 25 with building block 18, using again
Tf
2O but no base3), furnished disaccharide 23 in mediocre yield (32%)( Table 1). Cleav-
G
age of one of the two N-acetyl groups of 18 as well as of disaccharide 23 was the major
side reaction.
Removal of the Lev group using in situ generated hydrazine acetate yielded 28
(69%; Scheme 7). Again, partial loss of an N-acetyl group was observed. The
TMSOTf-catalyzed coupling of 28 with disaccharide 6 to give tetrasaccharide 29 was
achieved in 26% yield. The poor reactivity of the highly disarmed building block 28
most likely resulted in rearranged disaccharide 16 (Fig. 3)and the silylation of 28. In
addition, starting material 28 (35%)was re-isolated. Pentenyl functionalization was

Helvetica Chimica Acta – Vol. 89 (2006)2599
achieved by transforming the pentenyl moiety of tetrasaccharide 29 via a radical reac-
tion with HS(CH2)2
NHCbz [31] and catalytic amounts of AIBN [32] in benzene8)to the
G
Cbz-protected amine 30 (62%). An additional 27% of the mono-N-acetylated tetrasac-
charide was also obtained and used to proceed with the synthesis. To avoid elimination
of levulinate at the iduronic acid moiety, the Lev group was cleaved prior to global
hydrolysis. The free alcohol is less prone to elimination than the corresponding Lev
ester. Therefore, 30 was reacted with in situ generated hydrazine acetate. The crude
product, a mixture of mono- and di-N-acetate, due to partial cleavage of one of the
two N-acetates, was subsequently treated in a one-pot reaction with LiOH/H2O2 to
simultaneously oxidize the sulfine to the sulfone, and KOH/MeOH to furnish 31
(49%). The yield was diminished by inadvertent conversion of the Cbz-group to the
corresponding methyl carbamate and partial cleavage to the free amine. Hydrogena-
tion of 31 using H2 and Pd/C afforded 32.
3. Functionalization with Trautꢀs Reagent. To install the terminal thiol, 32 was
reacted with Trautꢀs reagent [14][33]. The thiol 33 (Fig. 5)can be used for conjugation
to maleimide-derivatized structures including chip surfaces and carrier proteins [14].
Fig. 5. Structure of the tetrasaccharide 33 (after functionalization of 32 with Trautꢀs reagent)
Conclusions. – We described the first total synthesis of the potential 10E4 tetrasac-
charide antigen 32. The use of 2-{2-[2-(benzylsulfanyl)ethoxy]ethoxy}ethyl as a linker
at the reducing end did not produce satisfying results as it complicated subsequent cou-
pling steps, including loss of selectivity for a glycosylation involving a participating
group. Employing the well-established pentenyl-linker and subsequent functionaliza-
tion steps on the tetrasaccharide stage helped us to overcome these challenges.
In the course of the synthesis of fully protected tetrasaccharide 30, it became evi-
dent that the N,N-diacetyl moiety is labile not only to basic but also to acidic conditions
(e.g., TFA, TfOH), even if the acid is used only at low temperature (e.g., 08)and/or in
catalytic amounts (e.g., TMSOTf). This finding confirmed observations by Crich and
Dudkin [24d]. In addition, the N,N-diacetyl was found to be neither fully compatible
with the conditions used for Lev deprotection (N2H4), nor with the radical conditions
used for linker functionalization to afford 30. These findings override the advantages
of the N,N-diacetyl moiety such as smooth installation and deprotection. N,N-Diacetyl
derivatives should be used with great care as a protecting group in oligosaccharide syn-
thesis. Biological investigations involving tetrasaccharide 33 are currently ongoing.
8)Benzene gave a significantly higher yield than THF.

2600
Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 7
a)Pyridine, AcOH, N H4·H2O, r.t.; 69%. b) 6, TMSOTf, CH2Cl2, À258 to À108; 26%. c)HS(CH )2-
2
2
A
THF, À58 to r.t., then 3M KOH, MeOH, r.t.; 49%. e) H2, Pd/C, MeOH/H2O 2 :1 (v/v), r.t.; 73%.
We are grateful to ETH-Zürich and the Swiss National Science Foundation (postdoctoral fellowship
to Dr. E. Castagnetti)for generous support of our work. We would like to thank CEM Corporation for
support of our microwave chemistry program. We thank P. Seiler for the determination of the X-ray crys-
tal structures and Dr. D. B. Werz for proofreading the manuscript.
Experimental Part
1. General. All chemicals used were reagent grade and used as supplied except where noted. CH2Cl2,
THF and toluene were purified by a Cycle-Trainer Solvent Delivery System. Pyridine and Et
A
freshly distilled over CaH2 under N2 before use. CCl3CN was distilled over P2O5 under Ar and stored

Helvetica Chimica Acta – Vol. 89 (2006)2601
O was distilled under Ar. Solvents for chromatography and workup procedures were distilled.
at 08. Tf2
ACHTREUNG
Reactions were performed under an Ar atmosphere except where noted. Abbreviations: AIBN: 2,2’-
Azoisobis[butyronitrile], BSP: (phenylsulfinyl)piperidine, DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene,
Cbz: PhCH2OC(O), DIPC: 1,3-diisopropylcarbodiimide, DIPEA: diisopropylethylamine (EtN(i-Pr)2),
A
DMAP: 4-(dimethylamino)pyridine, Fmoc-Cl: [(9H-fluoren-9-yl)methoxy]carbonyl chloride, h.v.: high
vacuum (0.01–0.1 Torr), LevOH: levulinic acid, m-CPBA: 3-chloroperoxybenzoic acid, NIS: N-iodosuc-
cinimide, TCA-Cl: trichloroacetyl chloride, TES: triethylsilane (Et
N
N
anhydride, TFA: trifluoroacetic acid, TFAA: trifluoroacetic anhydride, TMSOTf: trimethylsilyl trifluor-
omethanesulfonate, TsOH: p-toluenesulfonic acid. TLC: Merck silica gel 60 F254 plates; detection under
UV light at 254 nm and monitoring by solns. of ninhydrine (300 mg of ninhydrine, 3 ml of AcOH, and
100 ml of BuOH), anisaldehyde (23 ml of anisaldehyde, 9.4 ml of AcOH, 32 ml of conc. H2SO4, 880 ml
of EtOH)or ꢂMo-stainꢀ (25 g of phosphomolybdic acid, 10 g of Ce(SO )2 ·H2O, 60 ml of conc. H2SO4,
4
940 ml of H2O), followed by heating with a heat gun. FC: Fluka silica gel 60 (230–400 mesh). Gel-filtra-
tion chromatography: Sephadex G-25 from Amersham Biosciences. Prep. RP-HPLC: Waters HPLC sys-
tem (Waters, binary HPLC pump 1525, ELS detector 2420, dual l absorbance detector 2487)with SunFire
C8 column (SunFire 5 mm prep. column, C8 (150”10 mm)). Recycling prep. HPLC (LC-9101, Japan Ana-
lytical Industry Co., Ltd.); flow rate: 3.5 ml/min; solvent: CHCl3. Optical rotations ½aŠr:t: : Perkin-Elmer
D
241 polarimeter (10 cm, 1 ml cell); the solvents and concentrations (in g/100 ml) are indicated. Micro-
wave irradiation: CEM Discover microwave. IR Spectra: as 1–2% CHCl3 soln. on a Perkin-Elmer-782
spectrophotometer; in cmÀ1. NMR Spectra: 1H-NMR Spectra: Bruker AV600 (600 MHz), Bruker
DRX500 (500 MHz), Bruker DRX400 (400 MHz), or Varian VXR300 (300 MHz)spectrometers. 13C-
NMR Spectra: Bruker AV600 (150 MHz), Bruker DRX500 (125 MHz), Bruker DRX400 (100 MHz),
or Varian VXR300 (75 MHz)spectrometers. Chemical shifts d are given in ppm relative to resonances
1
of solvent, coupling constants J are given in Hertz (Hz). In ambiguous cases, H-assignment is based
on selective homonuclear decoupling experiments and 2D experiments. High-resolution mass spectra
were performed by the MS service at the Laboratory for Organic Chemistry, ETH Zürich (HR-
MALDI-MS)and by the MS service of the UNI-Fribourg (HR-ESI-MS)and are given in m/z.
2-{2-[2-(Benzylsulfanyl)ethoxy]ethoxy}ethyl 2-Azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-D-glu-
copyranoside (11). 2-Azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-D-glucopyranosyl trichloroacetimi-
date (10 [16]; 1.27 g, 2.4 mmol)and 2-{2-[2-(benzylsulfanyle)thoxy]ethoxy}ethanol [17] (0.92 g, 3.6
mmol)were co-evaporated with toluene (2”)and dissolved in CH 2Cl2 (48 ml). TMSOTf (46 ml, 0.24
mmol)was added, and the pale yellow soln. was stirred for 1 h at r.t. The reaction was quenched with
Et3N (1 ml), and the solvents were evaporated. FC (toluene/acetone 24 :1) afforded 11 (1.24 g, 83%)
N
as a mixture of a- and b-anomer (a/b 0.57:0.43). Colorless oil. Rf (toluene/acetone 12 :1)0.36. IR
1
(CHCl3): 3008w, 2924w, 2871w, 2112s, 1602w, 1496w, 1454w, 1369w, 1094s, 999m. H-NMR (CDCl3, 300
MHz): 2.59–2.65 (m, 2 H); 3.34–3.89 (m, 15.43 H); 3.91–4.03 (m, 1 H); 4.09 (t, J=9.5, 0.57 H);
4.25–4.35 (m, 1 H); 4.45 (d, J=7.8, 0.43 H); 4.79 (m, 1 H); 4.91 (m, 1 H); 4.96 (d, J=3.7, 0.57 H); 5.57
(s, 0.43 H); 5.58 (s, 0.57 H); 7.20–7.43 (m, 13 H); 7.46–7.51 (m, 2 H). 13C-NMR (CDCl3, 75 MHz):
30.7; 36.7; 62.7; 63.0; 66.2; 66.2; 67.6; 68.6; 69.0; 69.6; 70.2; 70.4; 70.4; 70.8; 70.9; 74.9; 75.0; 76.1; 77.3;
79.0; 81.6; 82.9; 98.7; 101.4; 101.4; 102.8; 126.0; 127.0; 127.9; 128.2; 128.3; 128.4; 128.4; 128.5; 129.0;
129.0; 137.2; 137.3; 137.9; 137.9; 138.5. HR-MALDI-MS: 644.2392 ([M+Na]+, C33
644.2401).
A
N3
G
N
2-{2-[2-(Benzylsulfanyl)ethoxy]ethoxy}ethyl 3-O-Benzyl-4,6-O-benzylidene-2-deoxy-2-(trichloroace-
tamido)-D-glucopyranoside (12). A soln. of 11 (1.18 g, 1.90 mmol)in THF (19 ml)and H 2O (2 ml)at 0 8
was treated with a 1M soln. of Me3P in THF (3.8 ml, 3.8 mmol). After stirring for 2 h at r.t., additional H2O
A
(2 ml)was added, and stirring was continued for 19 h at r.t. Then, the mixture was concentrated, co-
evaporated with toluene (3”)and CH Cl2 (3”), and dried for 2 h under h.v. The residue was dissolved
2
in CH2Cl2 (27 ml), and Et3N (0.66 ml, 4.8 mmol)and TCA-Cl (0.30 ml, 2.7 mmol)were added at 0 8.
A
The mixture was stirred for 1.5 h at r.t., diluted with CH2Cl2 (250 ml), washed with H2O (75 ml), sat.
NaHCO3 soln. (75 ml)and again H O (75 ml), dried (MgSO4)and concentrated. FC (toluene/AcOEt
2
9 :1 ! 4 :1)afforded 12a (0.71 g, 50%)and 12b (0.55 g, 39%).
Data of 12a. Colorless, highly viscous oil. Rf (toluene/AcOEt 85 :15)0.33. ½aŠr:t: =+45.6 (c=1.0,
D
CHCl3). IR (CHCl3): 3415w, 2995w, 2871w, 1718m, 1514m, 1454w, 1375w, 1087s, 1045m, 1003m. 1H-

2602
Helvetica Chimica Acta – Vol. 89 (2006)
NMR (CDCl3, 300 MHz): 2.60 (t, J=6.7, 2 H); 3.53–3.94 (m, 16 H); 4.22 (dd, J=9.3, 4.1, 1 H); 4.29 (dd,
J=10.3, 4.4, 1 H); 4.70 (d, J=11.5, 1 H); 4.90 (d, J=11.8, 1 H); 4.97 (d, J=3.7, 1 H); 5.60 (s, 1 H); 6.92 (d,
J=9.0, 1 H); 7.21–7.31 (m, 10 H); 7.38–7.41 (m, 3 H); 7.47–7.51 (m, 2 H). 13C-NMR (CDCl3, 75 MHz):
30.7; 36.7; 54.7; 62.9; 67.4; 68.9; 70.2; 70.3; 70.6; 70.8; 74.5; 76.1; 82.6; 92.6; 97.6; 101.3; 125.9; 127.0;
127.6; 127.7; 128.2; 128.3; 128.4; 128.9; 129.0; 137.2; 137.9; 138.3; 161.6. HR-MALDI-MS: 762.1418
([M+Na]+, C35
A
Cl3
G
N
Data of 12b. Colorless, highly viscous oil. Rf (toluene/AcOEt 85 :15)0.16. ½aŠr:t: =À8.8 (c=1.0,
D
CHCl3). IR (CHCl3): 3429w, 3008w, 2876w, 1717m, 1522m, 1454w, 1370w, 1175w, 1097s, 1029m, 1005m.
1H-NMR (CDCl3, 300 MHz): 2.59 (td, J=6.7, 1.2, 2 H); 3.52–3.81 (m, 15 H); 3.84–3.89 (m, 1 H); 4.19
(dd, J=10.1, 8.9, 1 H); 4.36 (dd, J=10.6, 5.0, 1 H); 4.69 (d, J=11.5, 1 H); 4.89 (d, J=11.5, 1 H); 5.04
(d, J=8.4, 1 H); 5.59 (s, 1 H); 7.06 (d, J=7.8, 1 H); 7.22–7.30 (m, 10 H); 7.36–7.39 (m, 3 H);
7.48–7.51 (m, 2 H). 13C-NMR (CDCl3, 75 MHz): 30.7; 36.7; 58.4; 66.1; 68.7; 68.8; 70.2; 70.5; 70.6; 70.8;
74.6; 76.5; 82.6; 92.6; 100.4; 101.2; 126.0; 127.0; 127.8; 128.1; 128.2; 128.4; 128.5; 128.9; 129.0; 137.2;
137.8; 138.2; 161.9. HR-MALDI-MS: 762.1418 ([M+Na]+, C35
A
Cl3
G
N
2-{2-[2-(Benzylsulfanyl)ethoxy]ethoxy}ethyl 3,6-Di-O-benzyl-2-deoxy-2-(trichloroacetamido)-a-D-
glucopyranoside (9). Compound 12a (0.108 g, 0.126 mmol)was co-evaporated with toluene (3”), dried
under h.v. overnight. Then, compound 12a was dissolved in CH2Cl2 (1 ml)and cooled to 0 8. The soln.
was treated with TES (0.14 ml, 0.87 mmol)and TFAA (21 ml, 0.15 mmol), and stirred at 08 for 10 min.
Then, TFA (56 ml, 0.73 mmol)was added dropwise. The mixture was stirred at 0 8 for 3 h, warmed to
158 in 2.5 h, and the reaction was quenched with ice-cold sat. NaHCO3 soln. The aq. phase was extracted
with CH2Cl2 (3”), and the combined org. phases were washed with sat. NaHCO3 soln., dried (MgSO4),
and concentrated. FC (hexane/AcOEt 4 :1 ! 3 :2)afforded 9 (72.5 mg, 67%). Colorless, highly viscous
oil. Rf (hexane/AcOEt 1:1)0.50. ½aŠr:t: =+47.3 (c=1.0, CHCl3). IR (CHCl3): 3419w, 3008w, 2919w, 2872w,
D
1718s, 1514m, 1454w, 1363w, 1303w, 1108s, 1056s. 1H-NMR (CDCl3, 300 MHz): 1.96 (br. s, 1 H); 2.62 (t,
J=6.9, 2 H); 3.53–3.86 (m, 17 H); 4.21 (td, J=9.6, 3.6, 1 H); 4.55 (d, J=12.1, 1 H); 4.62 (d, J=11.8, 1 H);
4.72 (d, J=11.5, 1 H); 4.80 (d, J=11.5, 1 H); 4.93 (d, J=3.6, 1 H); 7.12 (d, J=9.3, 1 H); 7.22–7.38 (m, 15
H). 13C-NMR (CDCl3, 75 MHz): 30.7; 36.7; 54.4; 67.2; 69.9; 70.1; 70.3; 70.4; 70.5; 70.8; 71.8; 73.7; 74.6;
80.0; 92.6; 97.3; 127.0; 127.6; 127.7; 127.8; 128.4; 128.4; 128.5; 128.8; 137.6; 137.9; 138.2; 161.5. HR-
MALDI-MS: 764.1574 ([M+Na]+, C35
A
Cl3
G
N
Methyl 2,3-Di-O-benzoyl-1-deoxy-4-O-levulinoyl-1-(phenylsulfanyl)-b-D-glucopyranosyluronate (8).
A soln. of 13 [18] (1.12 g, 2.35 mmol)in CH 2Cl2 (15 ml)at 0 8 was subsequently treated with DMAP (0.46
g, 3.8 mmol), DIPC (0.55 ml, 3.5 mmol), and LevOH (0.39 ml, 3.8 mmol). The mixture was stirred for 3 h
at r.t., diluted with AcOEt/hexane 3 :2 (v/v; 200 ml), filtered through a plug of silica, and concentrated.
FC (hexane/AcOEt 7:3 ! 1:1)afforded 8 (1.27 g, 89%). White solid. Rf (hexane/AcOEt 3 :2)0.20.
½aŠr:t: =+70.1 (c=1.0, CHCl3). IR (CHCl3): 3011w, 2957w, 1735s, 1602w, 1455w, 1440w, 1364w, 1155m,
D
1
1091m, 1070m, 1026m. H-NMR (CDCl3, 300 MHz): 2.03 (s, MeC); 2.33–2.64 (m, CH2CH2); 3.80 (s,
MeO); 4.23 (d, J=9.9, HÀC(5)); 4.98 (d, J=10.0, HÀC(1)); 5.39 (t, J=9.7, HÀC(2)or H ÀC(3)or
HÀC(4)); 5.42 (t, J=9.8, HÀC(2)or H ÀC(3)or H ÀC(4)); 5.71 (t, J=9.5, HÀC(2)or H ÀC(3)or H À
C(4)); 7.25–7.55 (m, 7 arom. H); 7.46–7.55 (m, 4 arom. H); 7.85–7.96 (m, 4 arom. H). 13C-NMR
(CDCl3, 75 MHz): 27.8 (CH2C(O)O); 29.6 (MeC); 37.7 (CC(O)CH2); 53.1 (MeO); 69.6, 69.9, 73.5,
76.3 (C(2), C(3), C(4), C(5)); 86.6 (C(1)); 128.3, 128.5, 128.6, 128.9, 129.7, 131.2, 133.3 (arom. CH,
arom. C); 164.7, 165.4, 166.7, 171.0 (C(O)); 205.3 (Me C(O)CH2). HR-MALDI-MS: 629.1441
([M+Na]+, C32
A
G
N
Methyl 2,3-Di-O-benzoyl-1-deoxy-4-O-{[(9H-fluoren-9-yl)methoxy]carbonyl}-1-(phenylsulfanyl)-b-
D-glucopyranosyluronate (14). A soln. of 13 [18] (0.149 g, 0.293 mmol)in pyridine (2 ml)at r.t. was
treated with Fmoc-Cl (0.151 g, 0.585 mmol). The mixture was stirred for 45 min at r.t., diluted with
AcOEt (40 ml), and washed with a soln. of H2O/conc. HCl 95 :5 (v/v; 3”20 ml), sat. aq. Na2CO3
(2”20 ml)and H 2O (20 ml), dried (MgSO4), and concentrated. FC (toluene/AcOEt 1:0 ! 9 :1)afforded
14 (0.172 g, 80%). White solid. Rf (toluene/AcOEt 9 :1)0.50. ½aŠr:t: =+48.0 (c=1.0, CHCl3). IR (CHCl3):
D
3067w, 3007w, 2957w, 1759s, 1736s, 1602w, 1451m, 1386w, 1092m, 1070m, 1025m, 968w. 1H-NMR (CDCl3,
300 MHz): 3.76 (s, Me); 4.07 (t, J=7.5, CHCH2); 4.24 (d, J=7.5, CH2
A
(d, J=9.9, HÀC(1)); 5.33 (t, J=9.7, HÀC(2)or H ÀC(3)or H ÀC(4)); 5.45 (t, J=9.6, HÀC(2)or H ÀC(3)
or HÀC(4)); 5.84 (t, J=9.4, HÀC(2)or H ÀC(3)or H ÀC(4)); 7.14–7.56 (m, 17 arom. H); 7.69–7.72 (m, 2

Helvetica Chimica Acta – Vol. 89 (2006)2603
arom. H); 7.87–7.89 (m, 2 arom. H); 7.95–7.98 (m, 2 arom. H). 13C-NMR (CDCl3, 75 MHz): 46.3
(CHCH2); 53.1 (Me); 69.9, 70.7, 73.1, 73.4, 76.0 (CH CH2, C(2), C(3), C(4), C(5)); 86.7 (C(1)); 119.8,
125.1, 127.0, 127.7, 128.3, 128.5, 128.9, 129.8, 131.2, 133.3, 141.0, 142.8, 142.9 (arom. CH, arom. C);
+
153.7 (OC(O)O); 164.7, 165.3, 166.6 (C(O)). HR-MALDI-MS: 753.1752 ([M+Na]+, C42
H34
U
A
;
calc. 753.1765).
2-{2-[2-(Benzylsulfanyl)ethoxy]ethoxy}ethyl (Methyl 2,3-Di-O-benzoyl-4-O-levulinoyl-b-D-glucopyr-
(15).
anosyluronate)-(1 ! 4)-3,6-di-O-benzyl-2-deoxy-2-(trichloroacetamido)-a-D-glucopyranoside
Compound 8 (81 mg, 134 mmol)and BSP (30.8 mg, 147 mmol)were co-evaporated with toluene (2”),
dried for 2 h under h.v., and dissolved in CH2Cl2 (2.7 ml). Freshly activated powdered 4-Š molecular
sieves were added, and the mixture was stirred for 30 min at r.t., cooled to À608, treated with Tf
C
2
added dropwise, and the soln. was allowed to warm to 58 in 80 min, stirred for 15 min at r.t., and the reac-
tion was quenched with Et3N (0.19 ml, 1.34 mmol). The mixture was diluted with CH2Cl2, then washed
G
with 10% Na2S2O3 soln. (10 ml), sat. NaHCO3 soln., and H2O, dried (MgSO4), and concentrated.
2”FC (i)hexane/acetone 4 :1 ! 7:3 and ii)toluene/AcOEt 4 :1 ! 3 :2)afforded 15 (52 mg, 31%).
Pale yellow, highly viscous oil. Rf (toluene/AcOEt 3 :2)0.50. ½aŠr:t: =+39.7 (c=0.35, CHCl3) . IR
D
(CHCl3): 3415w, 3005w, 2923w, 2862w, 1723s, 1600w, 1513w, 1451w, 1364w, 1313w, 1149m, 1093s,
1067m, 1036m. 1H-NMR (CDCl3, 300 MHz): 2.04 (s, Me (Lev)); 2.40–2.62 (m, CH2CH2 (Lev),
SCH2CH2); 3.38–3.77 (m, OCH2CH2OCH2CH2OCH2, SCH2Ph, HÀC(3)or
H
ÀC(4), HÀC(5),
CH2(6)); 3.52 (s, CO2
AHCTREUNG
C(4)); 4.35 (d, J=12.2, 1 H, PhCH); 4.63 (d, J=11.8, PhCH); 4.76 (d, J=7.4, HÀC(1’)); 4.77 (d,
J=12.2, PhCH); 4.94 (d, J=3.8, 1 H, HÀC(1)); 5.12 (d, J=11.8, PhCH); 5.34–5.51 (m, HÀC(2’) , HÀ
C(3’) , HÀC(4’)); 6.75 (d, J=8.5, NH); 7.21–7.57 (m, 21 arom. H); 7.83–7.90 (m, 4 arom. H). 13C-
NMR (CDCl3, 75 MHz): 27.8; 29.7; 30.7; 36.7; 37.8; 52.8; 54.5; 67.2; 67.4; 69.8; 70.1; 70.2; 70.3; 70.5;
70.8; 71.7; 72.4; 72.6; 73.7; 74.8; 77.3; 77.7; 92.5; 96.9; 100.2; 127.0; 127.2; 127.7; 128.2; 128.3; 128.4;
128.8; 128.8; 129.7; 129.7; 133.3; 133.4; 137.6; 138.3; 138.5; 161.4; 164.5; 165.4; 166.6; 171.0; 205.4.
HR-MALDI-MS: 1260.2933 ([M+Na]+, C61
A
Cl3
G
N
2-{2-[2-(Benzylsulfanyl)ethoxy]ethoxy}ethyl (Methyl 2,3-Di-O-benzoyl-b-D-glucopyranosyluronate)-
(1 ! 4)-3,6-di-O-benzyl-2-deoxy-2-(trichloroacetamido)-a-D-glucopyranoside (7). A soln. of 15 (43 mg,
34.7 mmol)in CH 2Cl2 (0.35 ml)at r.t. was subsequently treated with pyridine (83 ml), AcOH (55 ml),
and N2H4 ·H2O (2.4 ml, 69.4 mmol). The mixture was stirred for 1 h at r.t., and the reaction was quenched
with acetone (1 ml)and concentrated. FC (hexane/AcOEt 3 :2 ! 1:1)afforded 7 (38.4 mg, 97%). Pale
yellow, highly viscous oil. Rf (hexane/AcOEt 3 :2)0.20. ½aŠr:t: =+36.5 (c=1.0, CHCl3). IR (CHCl3):
D
3600w, 3422w, 3008w, 2892w, 1731s, 1600w, 1515w, 1452w, 1364w, 1313w, 1093s, 1070m, 1041m, 909w.
1H-NMR (CDCl3, 300 MHz): 2.58 (t, J=6.7, SCH2CH2); 3.28 (d, J=2.8, OH); 3.40–3.79 (m,
OCH2CH2OCH2CH2OCH2, SCH2Ph, HÀC(3)or H ÀC(4), HÀC(5), CH2(6), HÀC(5’)); 3.51 (s, CO2
G
138.3; 138.6; 161.5; 164.8; 166.3; 168.9. HR-MALDI-MS: 1162.2572 ([M+Na]+, C56
calc. 1162.2591).
H60
G
C
Pent-4-enyl N-Acetyl-2-amino-4,6-O-benzylidene-2-deoxy-a-D-glucopyranoside (20). To a soln. of N-
acetyl-D-glucosamine (19; 10 g, 45.2 mmol)in pent-4-en-1-ol (70 ml)was added TsOH·H 2O (0.86 g, 4.5
mmol), and the mixture was stirred at 908 for 24 h. The reaction was quenched with Et3N (10 ml), and
A
the solvents were evaporated. The residue was filtered through a plug of silica (MeOH/CH2Cl2 1:17),
co-evaporated with toluene (2”), dried under h.v. overnight, and suspended in MeCN (410 ml). The mix-
ture was treated with benzaldehyde dimethyl acetal (13.7 ml, 90.8 mmol)at r.t., its pH was adjusted to
3–4 by the addition of TsOH·H2O (2.7 g, 14.2 mmol), and stirred for 15 h at r.t. The reaction was
quenched with Et
C
D

2604
Helvetica Chimica Acta – Vol. 89 (2006)
1
3440w, 3007w, 2936w, 2871w, 1673s, 1509m, 1456w, 1376m, 1311w, 1126m, 1086s, 1033s, 997m. H-NMR
(CDCl3, 300 MHz): 1.67–1.76 (m, 2 H); 2.02 (s, 3 H); 2.10–2.18 (m, 2 H); 3.36–3.44 (m, 2 H); 3.56 (t,
J=9.2, 1 H); 3.67–3.84 (m, 3 H); 3.89 (td, J=9.5, 3.1, 1 H); 4.16–4.20 (m, 1 H); 4.24 (dd, J=9.5, 3.9, 1
H); 4.80 (d, J=3.8, 1 H); 4.98–5.08 (m, 2 H); 5.54 (s, 1 H); 5.74–5.88 (m, 1 H); 5.95 (d, J=8.7, 1 H);
7.32–7.37 (m, 3 H); 7.47–7.51 (m, 2 H). 13C-NMR (CDCl3, 75 MHz): 23.4; 28.5; 30.4; 54.1; 62.6; 67.5;
68.8; 70.4; 82.0; 97.7; 101.8; 115.2; 126.2; 128.1; 129.0; 137.0; 137.7; 171.2. HR-MALDI-MS: 400.1720
([M+Na]+, C20
N
N
Pent-4-enyl N-Acetyl-2-amino-3-O-benzyl-4,6-O-benzylidene-2-deoxy-a-D-glucopyranoside (21) . To
a suspension of 20 (0.50 g, 1.32 mmol), BaO (0.81 g, 5.28 mmol), and BaOH·8 H2O (0.21 g, 0.66
mmol)in DMF (2.2 ml)was added BnBr (0.32 ml, 2.65 mmol), and the mixture was stirred for 20 h at
r.t., diluted with CH2Cl2 (40 ml), and cooled to 08. At 08, 50% aq. AcOH (20 ml)was added to dissolve
the solids. The two phases were separated, and the org. phase was washed with ice-cold H2O, sat.
NaHCO3 soln., and again ice-cold H2O, dried (MgSO4), and concentrated. FC (toluene/AcOEt 10 :3
! 5 :2)afforded 21 (0.57 g, 92%). White solid. Rf (hexane/AcOEt 1:1)0.25. ½aŠr:t: =+101.9 (c=1.0,
D
CHCl3). IR (CHCl3): 3443w, 3008w, 2936w, 2874w, 1676s, 1513m, 1453w, 1375w, 1131m, 1088s, 1047s,
1
1001m. H-NMR (CDCl3, 300 MHz): 1.64–1.75 (m, 2 H); 1.92 (s, 3 H); 2.06–2.14 (m, 2 H); 3.38 (dt,
J=9.7, 6.5, 1 H); 3.64–3.88 (m, 5 H); 4.24–4.31 (m, 2 H); 4.65 (d, J=12.1, 1 H); 4.79 (d, J=3.7, 1 H);
4.93 (d, J=12.1, 1 H); 4.96–5.05 (m, 2 H); 5.34 (d, J=9.3, 1 H); 5.60 (s, 1 H); 5.72–5.85 (m, 1 H);
7.27–7.43 (m, 8 H); 7.48–7.53 (m, 2 H). 13C-NMR (CDCl3, 75 MHz): 23.3; 28.4; 30.3; 52.4; 62.7; 67.4;
68.9; 73.9; 76.0; 82.7; 98.0; 101.1; 115.0; 125.9; 127.6; 127.9; 128.2; 128.3; 128.9; 137.3; 137.8; 138.5;
169.6. HR-MALDI-MS: 490.2199 ([M+Na]+, C27
Pent-4-enyl
N
G
(22). To a soln. of 21 (0.415 g, 0.89 mmol)in CH 2Cl2 (3 ml)and MeCN (2 ml,) AcCl (0.32 ml, 4.5
mmol)and DIPEA (0.31 ml, 1.8 mmol)were added, and the mixture was heated in a microwave at
858 (80 W)for 3 h, diluted with CH 2Cl2, and washed with sat. NaHCO3 soln. The aq. phase was extracted
once with CH2Cl2. The combined org. phases were dried (MgSO4)and concentrated. FC (hexane/AcOEt
7:3)afforded 22 (0.45 g, 93%). Colorless oil. Rf (hexane/AcOEt 6 :4)0.45. ½aŠr:t: =+132.1 (c=1.0,
D
CHCl3). IR (CHCl3): 3008w, 2937w, 2871w, 1697m, 1678m, 1454w, 1368w, 1123m, 1092s, 1041m, 998m,
914w. 1H-NMR (CDCl3, 300 MHz): 1.63–1.73 (m, 2 H); 2.05–2.15 (m, 2 H); 2.28 (s, 6 H); 3.37 (dt,
J=9.7, 6.4, 1 H); 3.66–3.82 (m, 3 H); 3.93 (td, J=9.7, 4.5, 1 H); 4.30 (dd, J=10.1, 4.5, 1 H); 4.60 (dd,
J=10.9, 3.4, 1 H); 4.68 (dd, J=10.9, 8.1, 1 H); 4.72 (d, J=11.5, 1 H); 4.83 (d, J=3.7, 1 H); 4.94 (d,
J=11.5, 1 H); 4.98–5.07 (m, 2 H); 5.61 (s, 1 H); 5.72–5.86 (m, 1 H); 7.23–7.33 (m, 5 H); 7.38–7.44
(m, 3 H); 7.49–7.53 (m, 2 H). 13C-NMR (CDCl3, 75 MHz): 26.7; 28.6; 30.3; 58.8; 62.8; 68.0; 68.9; 73.8;
75.1; 84.0; 98.9; 101.2; 115.3; 125.9; 127.6; 127.7; 128.2; 129.0; 137.1; 137.5; 138.4; 175.2. HR-MALDI-
MS: 532.2297 ([M+Na]+, C29
N
N
Pent-4-enyl N,N-Diacetyl-2-amino-3,6-O-dibenzyl-2-deoxy-a-D-glucopyranoside (18). After co-evap-
orating with toluene (2”), 22 (0.386 g, 0.757 mmol)was dissolved in CH Cl2 (5 ml), cooled to 08, and
2
treated with TES (0.73 ml, 4.5 mmol)and TFAA (0.11 ml, 0.76 mmol). The mixture was stirred at 0
for 10 min, and TFA (0.29 ml, 3.8 mmol)was added dropwise. After the soln. was stirred at 0 8 for
2.5 h, it was warmed to 148 in 2.5 h, and, after stirring at 148 for 1 h, the reaction was quenched with Et3N
8
AHCTREUNG
(3.5 ml), diluted with CH2Cl2, and washed with sat. NaHCO3 soln. The aq. phase was extracted once with
CH2Cl2. The combined org. phases were dried (MgSO4)and concentrated. FC (toluene/AcOEt 9 :1 !
7:3)afforded 18 (259 mg, 67%). Colorless oil. Rf (toluene/AcOEt 7:3)0.33. ½aŠr:t: =+139.4 (c=1.0,
D
CHCl3). IR (CHCl3): 3497w 3008m, 2916w, 2862w, 1744w, 1676s, 1496w, 1454w, 1400w, 1365s, 1123m,
1
1046s, 916w. H-NMR (CDCl3, 300 MHz): 1.62–1.72 (m, 2 H); 2.06–2.13 (m, 2 H); 2.31 (s, 6 H); 2.53
(d, J=2.5, 1 H); 3.37 (dt, J=9.7, 6.4, 1 H); 3.64–3.82 (m, 5 H); 4.32 (dd, J=11.1, 3.6, 1 H); 4.51 (dd,
J=10.9, 7.8, 1 H); 4.55 (d, J=12.1, 1 H); 4.63 (d, J=12.1, 1 H); 4.74 (d, J=11.8, 1 H); 4.80 (d,
J=11.5, 1 H); 4.82 (d, J=3.7, 1 H); 4.95–5.06 (m, 2 H); 5.71–5.85 (m, 1 H); 7.25–7.38 (m, 10 H) .13C-
NMR (CDCl3, 75 MHz): 26.7; 28.6; 30.3; 59.3; 67.7; 69.7; 70.1; 73.2; 73.3; 73.7; 78.6; 98.4; 115.2; 127.6;
127.7; 127.8; 128.4; 128.5; 137.6; 138.6; 175.5. HR-MALDI-MS: 534.2463 ([M+Na]+, C29
N
N
calc. 534.2462).
(Methyl 2,3-Di-O-benzoyl-4-O-levulinoyl-b-D-glucopyranosyluronate) Trichloroacetimidate (24) . A
soln. of 8 (0.20 g, 0.33 mmol)in CH Cl2/H2O 100 :1 (v/v; 3.3 ml)was treated at r.t. with a soln. of NIS
2

Helvetica Chimica Acta – Vol. 89 (2006)2605
O (8 ml, 48 mmol)in CH 2Cl2 (4.5 ml). After 15 h, 10% Na2S2O3 soln. (10 ml)
(103 mg, 0.46 mmol)and Tf 2
ACHTREUNG
was added, and the layers were separated. The org. layer was washed with 10% NaHCO3 soln., dried
(MgSO4), and concentrated. FC (toluene/AcOEt 4 :1 ! 3 :2)afforded the hemiacetal (0.12 g, 0.23
mmol)that was dissolved in CH Cl2 (0.6 ml), and, at 08, CCl3CN (0.6 ml)and DBU (2.3 ml, 23 mmol)
2
were added. The soln. was stirred at 08 for 45 min, subsequently for 1.5 h at r.t. and concentrated. FC (tol-
uene/AcOEt 9 :1 ! 4 :1)afforded 24 (123 mg, 57%). White foam. Rf (toluene/AcOEt 4 :1)0.33.
½aŠr:t: =+113.3 (c=0.53, CHCl3). IR (CHCl3): 3344w, 3032w, 2954w, 1732s, 1678m, 1602w, 1585w,
D
1452w, 1354w, 1148m, 1108s, 1069m, 1029s, 972w. 1H-NMR (CDCl3, 300 MHz): 2.04 (s, CMe);
2.41–2.65 (m, CH2CH2); 3.79 (s, MeO); 4.64 (d, J=10.3, HÀC(5)); 4.84 (d, J=3.3, HÀC(1)); 5.53 (dd,
J=10.6, 3.3, HÀC(2)); 5.54 (t, J=10.1, HÀC(3)or H ÀC(4)); 6.10 (t, J=10.0, HÀC(3)or H ÀC(4));
7.32–7.41 (m, 4 arom. H); 7.47–7.55 (m, 2 arom. H); 7.91–7.96 (m, 4 arom. H); 8.66 (s, NH). 13C-
NMR (CDCl3, 75 MHz): 27.8 (CH2C(O)O); 29.7 (CMe); 37.7 (CC(O)CH2); 53.3 (MeO); 69.1, 69.4,
70.2, 70.8 (C(2), C(3), C(4), C(5)); 90.5 (CCl3); 92.8 (C(1)); 128.4, 128.7, 129.8, 129.8 (arom. CH);
133.4, 133.5 (arom. C); 160.1 (CCCl3); 165.1, 165.4, 167.0, 171.1 (C(O)); 205.3 (Me C(O)Me). HR-
MALDI-MS: 680.0453 ([M+Na]+, C28
A
G
N
Methyl 2,3-Di-O-benzoyl-1-deoxy-4-O-levulinoyl-1-phenylsulfinyl)-b-D-glucopyranosyluronate (25)
and Methyl 2,3-Di-O-benzoyl-1-deoxy-4-O-levulinoyl-1-(phenylsulfonyl)-b-D-glucopyranosyluronate
(27). A soln. of 8 (1.59 g, 2.55 mmol)in CH Cl2 (20 ml)at À788 was treated with a soln. of m-CPBA
2
(70–75%, 0.73 g, 2.9–3.2 mmol)in CH Cl2 (5 ml). The mixture was warmed to 08 in 1.5 h and stirred
2
at 08 for 30 min, the reaction was quenched with sat. NaHCO3 soln., and the soln. was diluted with
CH2Cl2. The aq. phase was extracted with CH2Cl2 (2”). The combined org. phases were washed with
brine, dried (MgSO4), and concentrated. FC (toluene/AcOEt 8 :2 ! 3 :2)afforded 25 (1.43 g, 90%;
3 :1 mixture of epimers)and 27 (0.13 g, 8%).
Data of 25. White solid. Rf (toluene/AcOEt 3 :2)0.16. ½aŠr:t: =+54.0 (c=1.0, CHCl3). IR (CHCl3):
D
3008w, 1739s, 1602w, 1452w, 1365w, 1152m, 1093m, 1070m, 1046w, 1027m. 1H-NMR (CDCl3, 300
MHz): 2.01 (s, 0.75 H, CMe); 2.02 (s, 2.25 H, CMe); 2.32–2.60 (m, CH2CH2); 3.72 (s, 2.25 H, MeO);
3.73 (s, 0.75 H, MeO); 4.15 (d, J=9.7, 0.25 H, HÀC(5)); 4.29 (d, J=9.0, 0.75 H, HÀC(5)); 4.58 (d,
J=9.3, 0.25 H, HÀC(1)); 4.80 (d, J=8.7, 0.75 H, HÀC(1)); 5.33 (t, J=8.9, 0.75 H, HÀC(4)); 5.38–5.45
(m, 0.25 H, HÀC(4)); 5.64–5.76 (m, HÀC(2), HÀC(3)); 7.30–7.53 (m, 10 arom. H); 7.67–7.78 (m, 3
arom. H); 7.85–7.91 (m, 2 arom. H). 13C-NMR (CDCl3, 75 MHz): 27.7 (CH2C(O)O); 29.6 (CMe);
37.6 (CC(O)CH2); 53.0, 53.5 (MeO); 66.9, 67.6, 68.6, 68.9, 72.4, 73.1, 76.0, 76.4 (C(2), C(3), C(4),
C(5)); 90.5, 92.9 (C(1)); 125.6, 125.8, 128.2, 128.3, 128.4, 128.5, 128.8, 128.9, 129.7, 129.8, 131.5, 131.8,
133.4, 138.5 (CH, arom.; C, arom.); 164.4, 165.2, 165.4, 166.0, 166.3, 170.9, 170.9 (C(O)); 205.3
(MeC(O)Me). HR-MALDI-MS: 645.1413 ([M+Na]+, C32
C
N
A
D
3032w, 2956w, 1741s, 1602w, 1585w, 1450w, 1331m, 1315w, 1150s, 1105m, 1094m, 1070m, 1026m. 1H-
NMR (CDCl3, 300 MHz): 2.03 (s, CMe); 2.33–2.60 (m, CH2CH2); 3.74 (s, MeO); 4.24 (d, J=9.7, HÀ
C(5)); 4.79 (d, J=9.7, HÀC(1)); 5.21 (t, J=9.3, HÀC(4)); 5.60 (t, J=9.3, HÀC(2)or H ÀC(3)); 5.70 (t,
J=9.0, HÀC(2)or H ÀC(3)); 7.33–7.41 (m, 4 arom. H); 7.48–7.55 (m, 2 arom. H); 7.58–7.63 (m, 2
arom. H); 7.70–7.75 (m, 1 arom. H); 7.82–7.86 (m, 2 arom. H); 7.93–7.97 (m, 2 arom. H); 7.99–8.03
(m, 2 arom. H). 13C-NMR (CDCl3, 75 MHz): 27.7 (CH2C(O)O); 29.6 (CMe); 37.6 (CC(O)CH2); 53.2
(MeO); 67.3, 68.8, 72.8, 76.0 (C(2), C(3), C(4), C(5)); 88.8 (C(1)); 128.3, 128.7, 128.9, 129.8, 129.9,
130.7, 133.4, 133.5, 134.1, 134.8 (arom. CH, arom. C); 164.7, 165.2, 165.8, 170.9 (C(O)); 205.3
(MeC(O)Me). HR-MALDI-MS: 661.1355 ([M+Na]+, C32
A
Pent-4-enyl (Methyl 2,3-Di-O-benzoyl-4-O-levulinoyl-b-D-glucopyranosyluronate)-(1 ! 4)-N,N-
diacetyl-2-amino-3,6-di-O-benzyl-2-deoxy-a-D-glucopyranoside (23). Compound 25 (0.91 g, 1.45 mmol)
was co-evaporated with toluene (2”), dried for 1 h under h.v., and dissolved in CH2Cl2 (29 ml). Freshly
activated, powdered 4-Š molecular sieves (1.86 g)were added, and the mixture was stirred for 30 min at
r.t. and cooled to À788. At À788, Tf
warm to À358 in 1 h and stirred at À358 for 20 min. Then, a soln. of 18 (0.57 g, 1.12 mmol)in CH 2Cl2 (3
ml)was added, the mixture was allowed to warm to 3 8 in 3 h, and the reaction was quenched with Et3N
U
A
(0.6 ml). The mixture was diluted with CH2Cl2, filtered through Celite, and washed with sat. NaHCO3
soln. The aq. layer was extracted with CH2Cl2 (2”), and the combined org. phases were washed with

2606
Helvetica Chimica Acta – Vol. 89 (2006)
brine, dried (MgSO4), and concentrated. FC (toluene/AcOEt 4 :1 ! 3 :2)and subsequent purification by
recycling prep. HPLC afforded 23 (382 mg, 32%). White foam. Rf (toluene/AcOEt 1:1)0.38.
½aŠr:t: =+86.5 (c=1.0, CHCl3). IR (CHCl3): 3008w, 2944w, 1736s, 1677w, 1602w, 1452w, 1365m, 1149m,
D
1093s, 1070m, 1028m. 1H-NMR (CDCl3, 400 MHz): 1.49–1.62 (m, OCH2
N
N
ACHTREUNG
OCH2CH2); 3.38 (dd, J=10.9, 1.7, HÀC(6)); 3.46–3.52 (m, HÀC(5), 1 H of OCH2CH2); 3.52 (s, CO2
ACHTREUNG
3.70 (dd, J=10.9, 2.6, HÀC(6)); 3.88 (d, J=9.6, HÀC(5’)); 4.05 (dd, J=10.0, 8.1, HÀC(4)); 4.38 (d,
J=12.1, PhCH); 4.43 (dd, J=11.2, 3.6, HÀC(2)); 4.50 (dd, J=11.2, 8.1, HÀC(3)); 4.61 (d, J=11.6,
PhCH); 4.75 (d, J=3.6, HÀC(1)); 4.77–4.87 (m, CH2=CH); 4.81 (d, J=10.3, HÀC(1’)); 4.82 (d,
J=12.1, PhCH); 5.14 (d, J=11.6, PhCH); 5.36–5.48 (m, HÀC(2’) , HÀC(3’) , HÀC(4’)); 5.64 (ddt,
J=17.1, 10.2, 6.6, CH2=CH); 7.19–7.57 (m, 16 arom. H); 7.84–7.90 (m, 4 arom. H). 13C-NMR
(CDCl3, 100 MHz): 26.6 (Me (NAc2)); 27.8 (CH2C(O)O); 28.2 (OCH2CH2); 29.5 (Me (Lev)); 30.0
(OCH2CH2CH2); 37.7 (MeC(O)CH2); 52.7 (MeO); 58.9 (C(2)); 67.4 (C(6)); 67.6 (OCH2CH2); 69.9
N
(C(4’)); 70.1 (C(5)); 71.7, 72.5 (C(2’), C(3’)); 72.8 (C(5’)); 73.5, 73.8 (PhCH2); 77.2 (C(3)); 78.2 (C(4));
98.3 (C(1)); 100.1 (C(1’)); 115.1 (CH2=CH); 127.1, 127.6, 128.1, 128.4, 128.4, 128.5, 128.6, 128.9, 129.0,
129.7, 129.9 (arom. CH); 133.4, 133.4, 137.5 (arom. C); 137.7 ( CH=CH2); 139.5 (arom. C); 164.6,
165.6, 166.8, 171.1, 175.4 (C(O)); 205.6 (MeC(O)Me). HR-MALDI-MS: 1030.3853 ([M+Na]+, C55
H61-
A
A
Pent-4-enyl (Methyl 2,3-Di-O-benzoyl-b-D-glucopyranosyluronate)-(1 ! 4)-N,N-diacetyl-2-amino-
3,6-di-O-benzyl-2-deoxy-a-D-glucopyranoside (28). A soln. of 23 (98.5 mg, 97.7 mmol)in CH Cl2 (3 ml)
2
at 08 was subsequently treated with pyridine (0.23 ml), AcOH (0.16 ml), and N2H4 ·H2O (4.4 ml, 127
mmol). The mixture was stirred for 1.25 h at r.t. Then, additional N2H4 ·H2O (2.4 ml, 69 mmol)was
added, and the resulting mixture was stirred for 45 min at r.t., subsequently the reaction was quenched
with acetone (1 ml), and the soln. was concentrated. Co-evaporation with toluene (2”), followed by
FC (toluene/AcOEt 7:3 ! 3 :2), afforded 28 (61.4 mg, 69%). White foam. Rf (toluene/AcOEt 1:1)
0.45. ½aŠr:t: =+83.5 (c=0.67, CHCl3). IR (CHCl3): 3600w, 3008w, 2954w, 1733s, 1600w, 1452w, 1365w,
D
1094s, 1069m, 1028m. 1H-NMR (CDCl3, 300 MHz): 1.53–1.60 (m, OCH2
N
N
CH2); 2.22 (s, NAc2); 3.22–3.29 (m, 1 H of OCH2CH2, OH); 3.39 (dd, J=10.7, 1.7, HÀC(6)); 3.47–3.55
(m, HÀC(5), 1 H of OCH2CH2); 3.52 (s, MeO); 3.71 (dd, J=10.7, 2.3, HÀC(6)); 3.77 (d, J=9.7, HÀ
C(5’)); 4.06–4.13 (m, HÀC(4), HÀC(4’)); 4.38 (d, J=12.1, PhCH); 4.45 (dd, J=11.1, 3.3, HÀC(2’));
4.51 (dd, J=11.2, 7.8, HÀC(3’)); 4.62 (d, J=11.2, PhCH); 4.74–4.87 (m, HÀC(1), HÀC(1’) , CH2=CH,
PhCH); 5.03 (d, J=11.2, PhCH); 5.28 (t, J=9.5, HÀC(3’)); 5.41 (dd, J=9.8, 8.0, HÀC(2’)); 5.64 (ddt,
J=17.1, 10.3, 6.7, CH2=CH); 7.18–7.57 (m, 16 arom. H); 7.84–7.87 (m, 2 arom. H); 7.94–7.96 (m, 2
arom. H). 13C-NMR (CDCl3, 75 MHz): 26.5; 28.1; 29.9; 52.5; 58.7; 67.2; 67.5; 70.0; 70.6; 71.3; 72.9;
73.7; 74.2; 74.9; 76.6; 77.6; 98.2; 100.1; 115.0; 127.0; 127.4; 128.0; 128.3; 128.3; 128.6; 128.9; 129.6;
129.8; 133.3; 137.4; 137.5; 139.3; 164.7; 166.4; 168.9; 175.4. HR-MALDI-MS: 932.3482 ([M+Na]+,
C
N
G
pyranosyluronate)-(1 ! 4)-N,N-diacetyl-2-amino-3,6-di-O-benzyl-2-deoxy-a-D-glucopyranoside
Compounds 28 (185 mg, 0.203 mmol)and 6 [15] (220 mg, 244 mmol)were co-evaporated with toluene
(2”), dried under h.v. overnight and dissolved in CH2Cl2 (4 ml). Freshly activated, powdered 4-Š molec-
ular sieves (337 mg)were added, and the mixture was stirred for 30 min at r.t. and cooled to À258. At
À258, TMSOTf (4.7 ml, 24 mmol)was added, and the soln. was warmed to À108 in 1 h and stirred at
À108 for 2.75 h. The reaction was quenched with Et
C
foam. Rf (toluene/AcOEt 2 :3)0.30. ½aŠr:t: =+15.6 (c=1.0, CHCl3). IR (CHCl3): 3008w, 2928w, 2112m,
D
1741s, 1453w, 1358w, 1153m, 1090m, 1028s. 1H-NMR (CDCl3, 600 MHz): 1.49–1.59 (m, OCH2
1.93–1.99 (m, OCH
N
N
(ddd, J=17.4, 6.8, 5.4, 1 H, CH2CH2 (Lev)); 2.53 (ddd, J=17.4, 8.0, 5.2, 1 H, CH2CH2 (Lev)); 2.64
(ddd, J=18.3, 6.8, 5.2, 1 H, CH2CH2 (Lev)); 2.74 (ddd, J=18.3, 8.0, 5.4, 1 H, CH2CH2 (Lev)); 3.22
(dd, J=10.2, 3.6, HÀC(2’’)); 3.25 (dt, J=11.2, 4.1, 1 H, OCH2CH2); 3.40 (dd, J=10.9, 1.6, HÀC(6));

Helvetica Chimica Acta – Vol. 89 (2006)2607
3.43–3.52 (m, HÀC(5), 1 H of OCH2CH2); 3.45 (s, CO2Me (IdoA)); 3.50 (s, CO2
N
G
J=10.2, 9.3, HÀC(3’’)); 3.69–3.71 (m, HÀC(6), HÀC(5’’)); 3.77 (d, J=9.6, HÀC(5’)); 3.79 (t, J=3.3, HÀ
C(3’’’)); 3.84 (t, J=9.6, HÀC(4’’)); 4.04 (dd, J=10.0, 8.4, HÀC(4)); 4.20 (dd, J=12.7, 2.5, HÀC(6’’)); 4.27
(t, J=9.4, HÀC(4’)); 4.41 (dd, J=11.1, 3.8, HÀC(2)); 4.42–4.44 (m, PhCH, HÀC(6’’)); 4.48 (dd, J=11.1,
8.4, HÀC(3)); 4.53 (d, J=10.8, PhCH); 4.56 (d, J=11.3, PhCH); 4.70 (d, J=11.4, PhCH); 4.73 (d,
J=10.8, PhCH); 4.75 (d, J=3.8, HÀC(1)); 4.76 (d, J=11.4, PhCH); 4.80–4.82 (m, 1 H, CH2=CH);
4.80 (d, J=8.0, HÀC(1’)); 4.81 (d, J=11.9, PhCH); 4.85 (ddd, J=17.1, 3.5, 1.6, 1 H, CH2=CH);
4.87–4.88 (m, HÀC(2’’’) , HÀC(5’’’)); 4.96 (d, J=3.6, HÀC(1’’)); 5.05 (d, J=11.3, PhCH); 5.07 (t,
J=3.4, HÀC(4’’’)); 5.12 (d, J=2.3, HÀC(1’’’)); 5.39 (dd, J=9.9, 8.0, HÀC(2’)); 5.57 (dd, J=9.9, 9.2,
HÀC(3’)); 5.64 (ddt, J=17.1, 10.3, 6.7, CH2=CH); 7.15–7.56 (m, 26 arom. H); 7.88–7.93 (m, 4 arom.
H). 13C-NMR (CDCl3, 150 MHz): 20.8, 20.9 (Me (OAc)); 26.6 (Me (NAc2)); 27.8 (CH2C(O)O); 28.2
(OCH2CH2); 29.7 (Me (Lev)); 30.0 (OCH 2CH2CH2); 37.5 (MeC(O)CH2); 52.1 (MeO (IdoA)); 52.8
G
(MeO (GlcA)); 59.0 (C(2)); 61.5 (C(6’’)); 63.8 (C(2’’)); 67.1, 67.8 (C(2’’’), C(5’’’)); 67.5 (C(6)); 67.6
(OCH2CH2); 68.1 (C(4’’’)); 70.2 (C(5)); 70.5 (C(5’’)); 71.9 (C(2’)); 73.0 (PhCH2); 73.1 (C(3’’’)); 73.4
(PhCH2); 73.6 (C(3’)); 73.8 (PhCH2); 74.4 (C(4’’)); 74.8 (C(5’)); 75.0 (PhCH2); 76.9 (C(3)); 77.8
(C(4’)); 78.3 (C(4)); 78.4 (C(3’’)); 97.7 (C(1’’’)); 98.3 (C(1)); 99.1 (C(1’’)); 100.4 (C(1’)); 115.1 (CH2=
CH); 127.1, 127.4, 127.6, 127.6, 128.0, 128.1, 128.1, 128.1, 128.2, 128.3, 128.4, 128.5, 128.5, 128.6, 129.0,
129.0, 129.1, 129.5, 129.6, 129.8, 133.0, 133.3 (arom. CH); 137.3 (arom. C); 137.5 ( CH=CH2); 137.6,
137.7, 139.3 (C, arom.); 164.8, 165.4, 167.3, 168.6, 169.8, 170.6, 171.7, 175.4 (C(O)); 205.8 (Me C(O)Me).
HR-MALDI-MS: 1611.5768 ([MÀHOAc+Na]+, C84
C
G
G
A
(0.6 ml)was added, and the soln. was instantly heated to reflux. After 2.25 h at reflux, the reaction
was quenched with hexene (0.4 ml), and the soln. was stirred for 15 min at r.t. and concentrated. FC (tol-
uene/acetone 4 :1 ! 2 :1)afforded 30 (42.5 mg, 62%). Colorless, highly viscous oil. Rf (toluene/AcOEt
2 :3)0.28. ½aŠr:t: =+31.8 (c=1.0, CHCl3). IR (CHCl3): 3456w, 3008w, 2928w, 2112m, 1740s, 1513w,
D
1
1453w, 1367m, 1155m, 1090m, 1028s, 909w. H-NMR (CDCl3, 500 MHz): 1.20–1.25 (m, CH2
CH2CH2);
1.36–1.44 (m, 2 CH2CH2CH2); 2.01 (s, AcO); 2.02 (s, AcO); 2.10 (s, Me (Lev)); 2.14 (s, NAc2);
E
2.35–2.49 (m, CH2 (Lev), SCH2); 2.54–2.61 (m, 1 H of CH2CH2 (Lev), SCH2); 2.68 (ddd, J=18.4, 7.9,
5.5, 1 H, CH2CH2 (Lev)); 3.14–3.19 (m, HÀC(2’’) , 1 H of OCH2CH2); 3.30–3.46 (m, HÀC(5), HÀ
C(6), 1 H of OCH2CH2, NCH2); 3.40 (s, MeO (IdoA)); 3.44 (s, MeO (GlcA)); 3.59–3.66 (m, HÀC(6),
HÀC(3’’) , HÀC(5’’)); 3.72 (d, J=9.7, HÀC(5’)); 3.74 (t, J=3.8, HÀC(3’’’)); 3.78 (t, J=9.6, HÀC(4’’));
3.98 (dd, J=9.9, 8.3, HÀC(4)); 4.14 (dd, J=12.7, 2.5, HÀC(6’’)); 4.20 (t, J=9.4, HÀC(4’)); 4.34–4.39
(m, HÀC(2), HÀC(6’’), PhCH); 4.42 (dd, J=11.1, 8.3, HÀC(3)); 4.47 (d, J=10.5, PhCH); 4.49 (d,
J=10.0, PhCH); 4.64 (d, J=11.4, PhCH); 4.67 (d, J=11.5, PhCH); 4.69 (d, J=4.3, HÀC(1)); 4.70 (d,
J=11.4, PhCH); 4.74 (d, J=13.2, PhCH); 4.76 (d, J=8.1, HÀC(1’)); 4.82–4.83 (m, HÀC(2’’’) , HÀ
C(5’’’)); 4.90 (d, J=3.6, HÀC(1’’)); 4.99 (d, J=11.4, PhCH); 5.01 (t, J=3.5, HÀC(4’’’)); 5.04 (s,
C(O)OCH2
G
J=9.5, HÀC(3’)); 7.09–7.48 (m, 31 arom. H); 7.82–7.87 (m, 4 arom. H). 13C-NMR (CDCl3, 125
MHz): 21.0; 21.1; 25.4; 26.8; 28.0; 29.0; 29.4; 29.9; 31.8; 32.4; 37.7; 40.4; 52.3; 53.0; 59.2; 61.7; 64.0;
67.0; 67.3; 67.9; 68.0; 68.3; 68.4; 70.5; 70.7; 72.1; 73.2; 73.3; 73.6; 73.8; 74.0; 74.5; 75.0; 75.2; 77.1; 77.5;
78.0; 78.6; 78.6; 97.9; 98.5; 99.3; 100.6; 127.3; 127.6; 127.7; 127.8; 128.2; 128.3; 128.3; 128.3; 128.4;
128.5; 128.5; 128.6; 128.7; 128.7; 128.8; 129.2; 129.2; 129.3; 129.7; 129.7; 130.0; 133.2; 133.6; 136.7;
137.5; 137.8; 137.9; 139.5; 156.5; 165.1; 165.6; 167.5; 168.8; 170.0; 170.8; 171.9; 175.6; 206.1. HR-
MALDI-MS: 1882.6708 ([M+Na]+, C96
5-{2-[(Benzyloxycarbonyl)amino]ethylsulfonyl}pentyl (3-O-Benzyl-a-L-idopyranosyluronate)-(1 !
4)-(2-azido-3-O-benzyl-2-deoxy-a-D-glucopyranoside)-(1 ! 4)-(b-D-glucopyranosyluronate)-(1 ! 4)-N-
acetyl-2-amino-3,6-di-O-benzyl-2-deoxy-a-D-glucopyranoside (31). A soln. of 30 (42.3 mg, 22.7 mmol)in
CH2Cl2 at 08 was subsequently treated with pyridine (0.22 ml), AcOH (0.15 ml), and a soln. of
N2H4·H2O in CH2Cl2 (1:4 (v/v) , 8ml, 45.5 mmol). The mixture was stirred for 2.25 h at r.t., the reaction

2608
Helvetica Chimica Acta – Vol. 89 (2006)
Table 2. Crystallographic Data for the Building Blocks 8, 14, and 25
8
14
25
Crystallized from
Empirical formula
Crystal temp. [K]
Crystal dimensions [mm]
Crystal system
Lattice parameters:
q Range [8]
a [Š]
AcOEt/hexane
AcOEt/hexane
AcOEt/hexane
C32
A
O10
A
C42
A
O10
A
C32
A
G
N
203(2)180(2)200(2)
0.13”0.10”0.09
monoclinic
0.14”0.11”0.08
monoclinic
0.22”0.18”0.16
monoclinic
2.03<q<25.04
2.84<q<25.02
3.56<q<25.05
10.0739(7)5.7218(1) 5.7329(2)
5.9307(4)29.4717(61)5.8855(4)
24.8830(19)10.5331(3) 16.4909(5)
b [Š]
c [Š]
a [8]
b [8]
90
94.682(2)95.924(1)90.575(1)
90 90
1481.68(18)1766.72(7) 1501.75(8)
90
90
90
g [8]
V [Š3]
Space group
Z
P21
2
1.360
0.168
3939
3939
3354
I>2s(I)
421
P21
2
1.374
0.154
4879
4879
4178
I>2s(I)
480
P21
2
1.377
0.170
4779
4779
4497
I>2s(I)
400
1calc [g cmÀ3
]
m [mmÀ1
]
Total reflections measured
Independent reflections
Reflections observed
Criterion
Parameters
Final R
wR2
Goodness-of-fit
D1(max,min) [eŠ
0.0591
0.1485
1.104
0.24, À0.23
0.0408
0.0967
0.908
0.17, À0.17
0.0459
0.1200
1.034
0.59, À0.26
À3
]
was quenched with acetone (1 ml), and the soln. was concentrated. The residue was co-evaporated with
toluene (2”), filtered through a plug of silica gel (CH2Cl2/acetone 7:3), dried under h.v. for 12 h, and dis-
solved in THF (3.2 ml). At À58, H2O2 (30%, 1.1 ml)and 1 M aq. LiOH (1.8 ml)were added, and the mix-
ture was stirred for 24 h at r.t. Then, MeOH (1.7 ml)and 3 M aq. KOH (3.2 ml)were added, and stirring
was continued for 17.5 h at r.t. Then, the mixture was neutralized with IR-120+ Amberlite resin, filtered,
co-evaporated with MeOH (2”), and concentrated. Purification by RP-HPLC (H2O (20% i-PrOH, 0.1%
TFA)/MeCN (20% i-PrOH, 0.1% TFA) 9 :1 for 2 min, 9 :1 ! 0 :1 in 20 min, flow rate 4.7 ml/min)
1
afforded 31 (16.0 mg, 49%). White, fluffy solid. tR 12.4–14.1 min. ½aŠr:t: =+51.1 (c=1.0, MeOH). H-
D
NMR (CD
3OD, 500 MHz): 1.47–1.51 (m, OCH2
U
CH2); 1.56–1.60 (m, OCH2
ACHTREUNG
SCH
G
ACHTREUNG
of OCH2CH2); 3.52 (t, J=6.7, NCH2); 3.56 (t, J=9.1, CH); 3.61–3.95 (m, HÀC(6), CH2(6’’) , 1 H of
OCH2CH2, 12 CH); 4.00–4.05 (m, HÀC(2), HÀC(6)); 4.31 (d, J=11.4, PhCH); 4.44 (d, J=8.2, HÀ
C(1’)); 4.44 (d, J=10.1, PhCH); 4.48 (d, J=11.8, PhCH); 4.57–4.63 (m, 3 PhCH); 4.66–4.69 (m, HÀ
C(1), PhCH, CH); 4.98 (d, J=11.0, PhCH); 5.03 (s, C(O)OCH2Ph); 5.15 (br. s, HÀC(1’’’)); 5.58 (d,
J=3.7, HÀC(1’’)); 7.10–7.40 (m, 25 arom. H). 13C-NMR (CD3
21.5 (Me); 25.1 (OCH2CH2CH2); 28.5 (OCH2CH2); 34.6 (NCH2); 51.9 (NCH2CH2); 52.8, 52.9 (C(2),
NCH2CH2); 60.0 (C(6’’)); 64.0 (C(2’’)); 66.5 (C(O)OCH2Ph); 66.9 (CH); 67.6 (O CH2CH2); 68.3
E
(C(6)); 68.8, 69.0, 70.9 (CH); 72.0 (PhCH2); 72.5 (CH); 73.2 (Ph CH2); 73.9 (CH); 74.2 (Ph CH2, CH);
74.5 (PhCH2); 74.9, 76.5, 76.9, 77.0, 77.5, 78.4, 78.9 (CH); 97.5 (C(1)); 98.3 (C(1 ’’)); 100.6 (C(1’’’));

Helvetica Chimica Acta – Vol. 89 (2006)2609
103.1 (C(1’)); 127.1, 127.2, 127.4, 127.7, 127.8, 127.9, 128.0, 128.2, 128.3, 128.4, 128.6 (CH, arom.); 137.0,
138.3, 138.4, 139.3 (arom. C); 157.4 (NC(O)O); 170.4 (N C(O)Me); 172.1, 172.2 (CC(O)O). HR-MALDI-
MS: 1454.5121 ([M+Na]+, C69
5-(2-Aminoethylsulfonyl)pentyl
A
N5
G
G
pyranoside)-(1 ! 4)-(b-D-glucopyranosyluronate)-(1 ! 4)-N-acetyl-2-amino-2-deoxy-a-D-glucopyrano-
side (32). Compound 31 (15.9 mg, 11.1 mmol)was dissolved in MeOH (2 ml)and H 2O (1 ml). Under an
Ar atmosphere, 100% Pd/C (15.9 mg)was added, and the Ar atmosphere exchanged for H 2. The mixture
was stirred for 18 h at r.t., filtered through Celite, co-evaporated with MeOH (2”), and concentrated. The
residue was purified by Sephadex G-25 chromatography (H2O/MeOH 9 :1)and lyophilized to afford 32
(7.4 mg, 73%). White, fluffy solid. ½aŠr:t: =+139.9 (c=0.57, H2O). 1H-NMR (D2
C
D
1 H); 3.48 (dd, J=10.2, 6.0, 1 H); 3.49 (dd, J=8.3, 5.8, 1 H); 3.53 (t, J=6.7, 2 H); 3.61 (t, J=6.7, 2 H);
3.64–3.67 (m, 1 H); 3.65 (dd, J=8.2, 7.0, 1 H); 3.69–3.92 (m, 13 H); 4.52 (d, J=4.5, HÀC(1)); 4.45 (d,
J=7.9, HÀC(1’)); 4.87 (d, J=2.8, HÀC(1’’’)); 5.65 (d, J=3.8, HÀC(1’’)). 13C-NMR (D2
G
C(1’), C(1’’), C(1’’’)); 177.0, 177.3, 178.6 (C(O)). HR-ESI-MS: 912.3123 ([M+H]+, C33
calc. 912.3125).
X-Ray Crystal-Structure Determination of 8, 14, and 25 (see the Table 2, and Figs. 2 and 4). The inten-
sities were collected on a Bruker-Nonius Kappa-CCD, MoKa radiation, l=0.7107 Š. The structure was
solved by direct methods [34] and refined by full-matrix least-squares analysis [35] including an isotropic
extinction correction. All non-H-atoms were refined anisotropically (H-atoms isotropic, wherby H-posi-
tions are based on stereochemical considerations). Table 2 shows the crystal data and details of the refine-
ment procedure.
CCDC-614522 (8), CCDC-614523 (14), and CCDC-614524 (25)contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of charge from the Cambridge Crystallo-
graphic Data Center via www.ccdc.cam.ac.uk/data_request/cif.
REFERENCES
[1] a)J. T. Gallagher, J. E. Turnbull, Glycobiology 1992, 2, 523; b)D. Spillmann, U. Lindahl, Curr.
Opin. Struct. Biol. 1994, 4, 677; c)K. S. Rostand, J. D. Esko, Infect. Immun. 1997, 65, 1; d)I. Capila,
R. J. Linhardt, Angew. Chem. 2002, 114, 426; Angew. Chem., Int. Ed. 2002, 41, 390; e)J. D. Esko, S.
B. Selleck, Annu. Rev. Biochem. 2002, 71, 435.
[2] C. A. A. van Boeckel, M. Petitou, Angew. Chem. 1993, 105, 1741; Angew. Chem., Int. Ed. 1993, 32,
1671; M. Petitou, C. A. A. van Boeckel, Angew. Chem. 2004, 116, 3180; Angew. Chem., Int. Ed.
2004, 43, 3118; L. Poletti, L. Lay, Eur. J. Org. Chem. 2003, 2999; J. D. C. CodØe, H. S. Overkleeft,
G. A. van der Marel, C. A. A. van Boeckel, Drug Discov. Today: Technol. 2004, 1, 317.
[3] A. K. Powell, E. A. Yates, D. G. Fernig, J. E. Turnbull, Glycobiology 2004, 14, 17R; D. L. Raben-
stein, Nat. Prod. Rep. 2002, 19, 312.
[4] C. Noti, P. H. Seeberger, Chem. Biol. 2005, 12, 731.
[5] J. T. Gallagher, A. Walker, Biochem. J. 1985, 230, 665.
[6] P. A. McBride, M. I. Wilson, P. Eikelenboom, A. Tunstall, M. E. Bruce, Exp. Neurol. 1998, 149, 447.
[7] S. B. Prusiner, Science 1982, 216, 136.
[8] D. A. Harris, ꢂPrions. Molecular and Cellular Biologyꢀ Horizon Scientific Press, Wymondham, UK,
1999.
[9] C. Leteux, W. Chai, K. Nagai, C. G. Herbert, A. M. Lawson, T. Feizi, J. Biol. Chem. 2001, 276, 12539.
[10] D. Hamza, R. Lucas, T. Feizi, W. Chai, D. BonnaffØ, A. Lubineau, ChemBioChem. 2006, 7, in press
(DOI 10.1002/cbic.200600356).
[11] T. Feizi, M. S. Stoll, C.-T. Yuen, W. Chai, A. M. Lawson, Methods Enzymol. 1994, 230, 484.
[12] T. Feizi, The Glycosciences Laboratory, Imperial College, personal communication.
[13] X. Liu, S. Siegrist, M. Amacker, R. Zurbriggen, G. Pluschke, P. H. Seeberger, ACS Chem. Biol. 2006,
1, 161.

2610
Helvetica Chimica Acta – Vol. 89 (2006)
[14] L. Schofield, M. C. Hewitt, K. Evans, M.-A. Siomos, P. H. Seeberger, Nature 2002, 418, 785.
[15] C. Noti, J. L. de Paz, L. Polito, P. H. Seeberger, Chem.–Eur. J., in press, DOI 10.1002/
chem.200601103.
[16] M. Takatani, T. Nakama, K. Kubo, S. Manabe, Y. Nakahara, Y. Ito, Y. Nakahara, Glycoconj. J. 2000,
17, 361; H. A. Orgueira, A. Bartolozzi, P. Schell, R. E. J. N. Litjens, E. R. Palmacci, P. H. Seeberger,
Chem.–Eur. J. 2003, 9, 140.
[17] P. Critchley, M. N. Willand, A. K. Rullay, D. H. G. Crout, Org. Biomol. Chem. 2003, 1, 928; N.
Boden, R. J. Bushby, S. Clarkson, S. D. Evans, P. F. Knowles, A. Marsh, Tetrahedron 1997, 53, 10939.
[18] L. J. van den Bos, J. D. C. CodØe, J. C. van der Toorn, T. J. Boltje, J. H. van Boom, H. S. Overkleeft,
G. A. van der Marel, Org. Lett. 2004, 6, 2165; J. D. C. CodØe, Ph.D. Thesis, Universiteit Leiden, NL-
Leiden, 2004.
[19] O. J. Plante, E. R. Palmacci, P. H. Seeberger, Science 2001, 291, 1523.
[20] H. Yamada, M. Nakatani, T. Ikeda, Y. Marumoto, Tetrahedron Lett. 1999, 40, 5573; A. BØrces, G.
Enright, T. Nukada, D. M. Whitfield, J. Am. Chem. Soc. 2001, 123, 5460; A. Imamura, H. Ando, S.
Korogi, G. Tanabe, O. Muraoka, H. Ishida, M. Kiso, Tetrahedron Lett. 2003, 44, 6725; S. Parsons, A.
Proud, S. Flitsch, P. Wood, personal communication, 2004; X. Guo, C. Cheng, X. Liu, X. Liu, R.
Wang, D. Xie, L. Wang, Y. Zhao, J. Mol. Struct.: THEOCHEM 2004, 710, 201.
[21] L. J. Farrugia, J. Appl. Crystallogr. 1997, 30, 565.
[22] D. Crich, M. Smith, J. Am. Chem. Soc. 2001, 123, 9015; D. Crich, A. Banerjee, W. Li, Q. Yao, J. Car-
bohydr. Chem. 2005, 24, 415.
[23] D. R. Mootoo, P. Konradsson, U. Udodong, B. Fraser-Reid, J. Am. Chem. Soc. 1988, 110, 5583; B.
Fraser-Reid, U. E. Udodong, Z. Wu, H. Ottosson, J. R. Merritt, C. S. Rao, C. Roberts, R. Madsen,
Synlett 1992, 927.
[24] a)J. C. Castro-Palomino, R. R. Schmidt, Tetrahedron Lett. 1995, 36, 6871; b)A. V. Demchenko, G.-
J. Boons, Tetrahedron Lett. 1998, 39, 3065; c)G. J. S. Lohman, P. H. Seeberger, J. Org. Chem. 2004,
69, 4081; d)D. Crich, V. Dudkin, J. Am. Chem. Soc. 2001, 123, 6819.
[25] H. Paulsen, Angew. Chem. 1982, 94, 184; Angew. Chem., Int. Ed. 1982, 21, 155.
[26] P. Sinay¨, Pure Appl. Chem. 1978, 50, 1437; A. Lubineau, D. BonnaffØ, Eur. J. Org. Chem. 1999, 2523.
[27] R. Lucas, D. Hamza, A. Lubineau, D. BonnaffØ, Eur. J. Org. Chem. 2004, 2107.
[28] E. Fischer, Ber. Dtsch. Chem. Ges. 1914, 47, 1980; L. F. Bornaghi, S.-A. Poulsen, Tetrahedron Lett.
2005, 46, 3485.
[29] P. Szabó, J. Chem. Soc., Perkin Trans. 1 1989, 919.
[30] N. Khiar, I. Alonso, N. Rodriguez, A. Fernandez-Mayoralas, J. Jimenez-Barbero, O. Nieto, F. Cano,
C. Foces-Foces, M. Martin-Lomas, Tetrahedron Lett. 1997, 38, 8267; D. Crich, J. Mataka, S. Sun,
K.-C. Lam, A. L. Rheingold, D. J. Wink, Chem. Commun. 1998, 2763; P. H. Buist, B. Behrouzian,
K. D. MacIsaac, S. Cassel, P. Rollin, A. Imberty, C. Gautier, S. PØrez, P. Genix, Tetrahedron: Asym-
metry 1999, 10, 2881; N. Khiar, I. Fernµndez, C. S. Araffljo, J.-A. Rodríguez, B. Suµrez, E. lvarez, J.
Org. Chem. 2003, 68, 1433.
[31] I. Shinkai, T. Liu, R. Reamer, M. Sletzinger, Synthesis 1980, 924.
[32] T. Buskas, E. Sçderberg, P. Konradsson, B. Fraser-Reid, J. Org. Chem. 2000, 65, 958; J. L. de Paz, C.
Noti, P. H. Seeberger, J. Am. Chem. Soc. 2006, 128, 2766.
[33] R. R. Traut, A. Bollen, T.-T. Sun, J. W. B. Hershey, J. Sundberg, L. R. Pierce, Biochemistry 1973, 12,
3266; R. Jue, J. M. Lambert, L. R. Pierce, R. R. Traut, Biochemistry 1978, 17, 5399.
[34] G. M. Sheldrick, ꢂSHELXS-97 Program for the Solution of Crystal Structuresꢀ, University of Gçt-
tingen, Gçttingen, 1997.
[35] G. M. Sheldrick, ꢂSHELXL-97 Program for the Refinement of Crystal Structuresꢀ, University of
Gçttingen, Gçttingen, 1997.
Received July 20, 2006