Synthesis of a 1,3 β-glucan hexasaccharide designed to target vaccines to the dendritic cell receptor, Dectin-1

Article abstract of DOI:10.1016/j.carres.2015.03.007

Transformation of 3-O-benzyl-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose into 2,4,6-tri-O-benzoyl-3-O-benzyl glucopyranosyl imidate proceeded efficiently via crystalline benzyl and per-benzoylated derivatives. This imidate glycosylated di-O-isopropylidene-α-d-glucofuranose in high yield and glycosylation of the disaccharide after removal of the 3′-O-benzyl ether afforded the β1,3 linked trisaccharide in excellent yield. Di- and trisaccharides imidates were readily prepared from the furanose terminated glycosylation products but both were unreactive in glycosylation reaction with the debenzylated di- and trisaccharide alcohols. The 3′-O-benzyl perbenzoylated disaccharide pyranose derivative could be selectively debenzoylated and converted to the corresponding perbenzoylated 4,6:4′,6′-di-O-benzylidene derivative. Lewis acid catalyzed glycosidation gave the selectively protected disaccharide ethylthioglycoside in good overall yield. Glycosidation of this thioglycoside donor with 5-methoxycarbonylpentanol gave the disaccharide tether glycoside and after catalytic removal of benzyl ether the resulting disaccharide alcohol was glycosylated by the thioglycoside in a 2+2 reaction to yield a tetrasaccharide. Repetition of selective deprotection of the terminal 3-O-benzyl ether followed by glycosylation by the disaccharide thioglycoside gave a protected hexasaccharide. Hydrogenolysis of this hexasaccharide followed by transesterification and second hydrogenolysis to remove a residual benzyl group gave the target hexasaccharide glycoside 1 as a Dectin-1 ligand functionalized to permit covalent attachment to glycoconjugate vaccines and thereby facilitate improved antigen processing by dendritic cells.

Full text of DOI:10.1016/j.carres.2015.03.007

Carbohydrate Research 408 (2015) 96e106
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Synthesis of a 1,3
b-glucan hexasaccharide designed to target vaccines
to the dendritic cell receptor, Dectin-1
Hassan R.H. Elsaidi , Eugenia Paszkiewicz , David R. Bundle a
a
,
b
a
, *
a
Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Alexandria, Alexandria, Egypt
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 January 2015
Received in revised form
Transformation of 3-O-benzyl-1,2:5,6-di-O-isopropylidene-
a
-
D
-glucofuranose into 2,4,6-tri-O-benzoyl-
3-O-benzyl glucopyranosyl imidate proceeded efficiently via crystalline benzyl and per-benzoylated
derivatives. This imidate glycosylated di-O-isopropylidene-
a
-
D
-glucofuranose in high yield and glyco-
1,3 linked trisaccharide
3
March 2015
0
sylation of the disaccharide after removal of the 3 -O-benzyl ether afforded the
b
Accepted 6 March 2015
Available online 14 March 2015
in excellent yield. Di- and trisaccharides imidates were readily prepared from the furanose terminated
glycosylation products but both were unreactive in glycosylation reaction with the debenzylated di- and
0
trisaccharide alcohols. The 3 -O-benzyl perbenzoylated disaccharide pyranose derivative could be
Keywords:
0
0
selectively debenzoylated and converted to the corresponding perbenzoylated 4,6:4 ,6 -di-O-benzylidene
derivative. Lewis acid catalyzed glycosidation gave the selectively protected disaccharide ethyl-
thioglycoside in good overall yield. Glycosidation of this thioglycoside donor with 5-
methoxycarbonylpentanol gave the disaccharide tether glycoside and after catalytic removal of benzyl
ether the resulting disaccharide alcohol was glycosylated by the thioglycoside in a 2þ2 reaction to yield a
tetrasaccharide. Repetition of selective deprotection of the terminal 3-O-benzyl ether followed by
glycosylation by the disaccharide thioglycoside gave a protected hexasaccharide. Hydrogenolysis of this
hexasaccharide followed by transesterification and second hydrogenolysis to remove a residual benzyl
group gave the target hexasaccharide glycoside 1 as a Dectin-1 ligand functionalized to permit covalent
attachment to glycoconjugate vaccines and thereby facilitate improved antigen processing by dendritic
cells.
Beta 1,3-glucan synthesis
Beta 1,3-glucan hexasaccharide
Synthetic ligand for Dectin-1
Dendritic cell ligand
©
2015 Elsevier Ltd. All rights reserved.
1
. Introduction
to tetanus toxoid for DC uptake and processing.16 The simple
trimannoside-tetanus toxoid vaccine was a potent immunogen in
17
Conjugate vaccines containing 1,3 linked
epitopes can afford protection against fungal pathogens.
same glycans are ligands for Dectin-1, a C-type lectin receptor
present on the surface of dendritic cells (DCs).
prize for Medicine recognized the concept of targeting antigens to
dendritic cells for uptake and processing by these cells of the innate
b
-glucans as B-cell
rabbits but not mice and became an effective immunogen in mice
1
e3
16
The
when laminarin was conjugated to it. Five-fold higher antibody
titers to the mannan were observed and shown to be attributable to
DC processing of the antigen, whereas uptake of conjugates lacking
laminarin was so poor it could not be detected by uptake of fluo-
rescently labeled antigen. We also showed that Dectin-1 mediated
uptake of this tri-component vaccine resulted in stimulation of
innate immune cells to produce cytokines, mainly interleukin-6 (IL-
4
e11
The 2011 Nobel
immune system leading to improved immune responses against
tumor antigens.1
2e15
The possibility of targeting vaccines to DCs by
attaching carbohydrate ligands for one of the several C-type lectin
receptors that occur on DCs has provoked considerable interest.
6) and tumor-necrosis factor (TNF
of CD4 positive T helper lymphocytes (T
17 producing T -17 cells [16]. IL-17 is a potent recruitment factor
for neutrophils while T 1 cells are involved in B cell stimulation
a
), which induce differentiation
H
cells) intoT 1 cells and IL-
H
Since Dectin-1 binds
b
-glucan this property was used to direct an
-mannotriose epitope conjugated
H
otherwise poorly immunogenic
b
H
and antibody class switching. Both are desirable attributes of an
anti-fungal immune response.
These findings promoted us to consider using a synthetic
glucan that lacks the 1,6 side chains present in laminarin to target
b1,3-
*
Corresponding author. Tel.: þ1 780 492 8808; fax: þ1 780 492 7705.
E-mail address: dave.bundle@ualberta.ca (D.R. Bundle).
http://dx.doi.org/10.1016/j.carres.2015.03.007
008-6215/© 2015 Elsevier Ltd. All rights reserved.
0

H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
97
vaccines to DCs. The size of the
Dectin-1 has been cited to range between hexasaccharide up to
oligosaccharide as large as 15e25 mers.
b
1,3-glucan ligand recognized by
2.2. Attempted glycosylation with a trisaccharide imidate donor 10
Our initial plan was to synthesize the (1/3) hexaglucan via a
8
e11
It is rare for the binding
b
sites of either lectins or antibodies to make crucial contacts with
oligosaccharides larger than a hexasaccharide and we envisaged a
hexasaccharide presented in multivalent format to be a suitable
ligand to evoke strong uptake of a conjugate by DCs. Unpublished
3þ3 approach. With trisaccharide glycosyl acceptor 9 in hand,
trisaccharide imidate 10 was synthesized in good yield by acid-
2
8
catalyzed hydrolysis of 8 followed by perbenzoylation of the
resulting tetraol using BzCl and pyridine, removal of the anomeric
3
data in our laboratory confirms that presentation of
b
-1,3-glucan in
ester using methylamine and treatment of the resulting trisac-
multivalent format leads to enhanced activation of DCs. We have
therefore envisioned a hexasaccharide 1 derivatized for attachment
to a dendrimer that could in turn be conjugated to a protein carrier
charide pyranose derivative with trichloroacetonitrile and DBU in
2
9
DCM. Attempts to glycosylate acceptor 7 or 9 using imidate donor
10 employing a catalytic amount of TMSOTf at room temperature
for two days failed to yield any hexasaccharide. Increasing the
amount of TMSOTf to as high as two equivalents also with a reac-
tion time for two days failed to provide the anticipated product
(Scheme 3). Other variables examined included increasing the
equivalence of both donor and acceptor (for glycosylations of 7 and
9 three equivalents of donor were used), performing glycosylation
reactions at reflux in DCM and also with toluene as solvent at
bearing an epitope of interest. This required a robust synthesis of b-
1
,3-glucan attached to a tether for conjugation to terminal amino
18,19
groups of a dendrimer. 5-Methoxycarbonyl-pentanol
was cho-
sen as the linker because of its compatibility with deprotection of
the assembled oligosaccharide and its compatibility with different
conjugation reactions1
8,20
(Fig. 1).
Employing different glycosylation methods several groups have
2
1
22
ꢀ
achieved the synthesis of
b
-glucans; linear tetra-, penta-, hexa-
100 C. All of these modifications were without effect. Different
2
3e25
26
8
,
dodeca- and hexadecasaccharides, and a branched hep-
activators were not tried. Since unreacted imidate was not recov-
ered we assumed the failure to obtain glycosylation products was
due to low reactivity of the acceptors.
8
tadeca-oligosaccharide. Some difficulties were reported in
obtaining high yield glycosylation reactions accompanied in one
case by the unusual conformation of an internal glucose residue,
which adopted a twist boat conformation, despite the presence of a
2.3. Attempted glycosylation with a disaccharide imidate donor 12
2
5
4
,6-O-benzylidene group. We report here our attempts to syn-
thesize a hexasaccharide -1,3-linked glucan attached to a tether.
b
We examined the possibility of coupling a disaccharide imidate
donor to either di or trisaccharide glycosyl acceptor. Hydrolysis of
the acetal groups of disaccharide 6 followed by perbenzoylation of
the resulting tetraol gave the perbenzoylated disaccharide 11. Se-
2
. Results and discussion
3
lective removal of the anomeric benzoate of 11 using methylamine
We initially envisioned a convergent synthesis of
b(1/3) hex-
followed by treatment with trichloroacetonitrile and DBU gave
asaccharide starting from -glucose diacetonide as it allows facile
D
3
imidate 12. Glycosylation of either acceptor 7 or 9 was again
selective protection at C-3. Benzylation of diisopropylidene gluco-
furanose using benzyl chloride and sodium hydride in DMF affor-
ded 2 in almost quantitative yield.27 Subsequent acid-catalyzed
attempted but in this case disaccharide donor 12 was tried using
first a catalytic amount and then up to two equivalent of TMSOTf for
two days. No glycosylation product was obtained in either case
2
8
hydrolysis of compound 2 afforded crystalline tetraol 3, which
was then benzoylated using benzoyl chloride in pyridine furnishing
crystalline perbenzoate 4. Selective removal of anomeric benzoate
(Scheme 4).
3
2.4. Attempted tetrasaccharide synthesis with monosaccharide
imidate donor 5
was achieved via treatment with methylamine and the resulting
alcohol was converted into imidate 5 upon treatment with tri-
2
9
chloroacetonitrile and DBU. Synthesis of building block 5 could be
performed efficiently on a large scale since column chromatog-
raphy was only required for compound 5 (Scheme 1).
Unsuccessful attempts to execute donoreacceptor glycosylation
reactions consisting of the following combinations, 3þ3, 3þ2, 2þ3
or 2þ2 prompted us to examine the possibility of using the
monosaccharide imidate donor 5 to extend trisaccharide 9 to form
the corresponding tetrasaccharide under similar conditions to
those previously tried.
2.1. Disaccharide and trisaccharide synthesis
Glycosylation of diisopropylidene- -glucofuranose by imidate 5
D
However, after two days no glycosylation product was observed
(Scheme 5). Although synthesis with imidate 5 did not provide the
intended larger oligosaccharides, it did provide an optimized route
for large-scale synthesis of b(1/3)elinked trisaccharide 8 via a
series of transformations that required only limited column chro-
gave disaccharide 6 in high yield after crystallization. Disaccharide
alcohol 7 was obtained by hydrogenolysis of the benzyl ether.
Formation of trisaccharide 8 was accomplished in high yield from
glycosyl acceptor 7 and imidate donor 5 by employing a catalytic
2
9
amount of TMSOTf in DCM for 45 min. The trisaccharide alcohol 9
was obtained by hydrogenolysis using the same procedure as
compound 7. The stereoselectivity of the two glycosylation re-
actions was controlled by neighboring group participation of the O-
matography for purification.
2.5. Synthesis of disaccharide thioglycoside donor 15
2
J
-benzoyl group and was confirmed by measuring heteronuclear
C-1,H-1 coupling constants of 160e161.4 Hz (Scheme 2).
An alternative approach was investigated using a thioglycoside
donor. Treatment of disaccharide 11 with 0.5 equiv of freshly
1
30
Fig. 1. Structure of the b1,3-glucan tether glycoside 1 designed to serve as a dendritic cell targeting ligand. After conjugation to a glycoconjugate vaccine the resulting vaccine
construct can be more effectively processed by these antigen presenting cells.

98
H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
ꢀ
Scheme 1. (i) BnCl, NaH, DMF, 97%; (ii) Dioxane/6 M HCl (4:1), overnight, 93.5%; (iii) BzCl, pyridine, 0 C, 92%; (iv) CH
3
NH
2
3
, DCM/THF, 4 h; CCl CN, DCM, DBU, 30 min, 84%.
prepared NaOCH
3
for one hour conveniently transesterified only
dimethylacetal and a catalytic amount of p-toluenesulfonic acid to
0
0
31
32
those benzoate groups at C-4, C-6, C-4 and C-6 affording tetraol 13
in 72% yield. Longer reaction time resulted in removal of other
benzoate groups. Tetraol 13 reacted with benzaldehyde
give the diacetal 14 in a good yield. Then glycosidation of 14 by
thioethanol using BF $Et O promotor in DCM gave a 83% yield of
thioglycoside 15 (Scheme 6).
3
2
2 3 2 3
Scheme 2. (i) DCM, TMSOTf, 45 min, 89%; (ii) Pd/C, H , DCM/CH OH (1:4), overnight, 93%; (iii) 5, DCM, TMSOTf, 4 h, 91%; (iv) Pd/C, H , DCM/CH OH (1:4), overnight, 89%.

H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
99
3 2 3
Scheme 3. (i) 6 M HCl/Dioxane, 17 h; BzCl, pyridine, 2 h; CH NH , DCM/THF (1:10), 3 h; CCl CN, DCM, DBU, 30 min, 78% over four steps; (ii) TMSOTf, DCM, rt, 2 days.
3 2 3
Scheme 4. (i) 6 M HCl/Dioxane, 17 h; BzCl, pyridine, 2 h, 82%; (ii) CH NH , DCM, 3 h; CCl CN, DCM, DBU, 30 min, 81% over two steps; (iii) TMSOTf, DCM, rt, 2 days.
2
.6. Hexasaccharide synthesis utilizing the disaccharide
disaccharide glycoside 16 in 89% yield. Debenzylation of compound
16 using Pd/C under hydrogen atmosphere for three hours fur-
nished alcohol 17 with minimal hydrogenolysis of benzylidene
acetals. Glycosylation of disaccharide alcohol 17 by donor 15 using
the same procedures as for 16 gave 18, which was in turn converted
thioglycoside donor 15
5
-Methoxycarbonylpentanol was efficiently glycosylated by
3
2
disaccharide donor 15 using NISeAgOTf
activation to give
Scheme 5. (i) TMSOTf, DCM, rt, 2 days.

100
H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
3 3 3 2 3 2
Scheme 6. (i) DCM/CH OH (1:2), NaOCH , 1 h, 72%; (ii) PhCH(OCH ) , acetonitrile, p-TsOH, 1 h, 94%; (iii) DCM, EtSH, BF $Et O, overnight, 83%.
to tetrasaccharide alcohol 19 by controlled hydrogenolysis. Finally
NISeAgOTf32 mediated glycosylation of 19 by donor 15 furnished
the protected hexasaccharide 20 in 87% yield. A coupled HSQC
experiment was used to confirm the stereochemistry of all newly
formed glycosidic linkages after each glycosylation cycle. The
internal standards of the residual protonated solvent peaks;
7.24 ppm for solutions in CDCl , and to 0.1% external acetone (
2.225 ppm) for solutions in D
the aid of GCOSY, TOCSY, and TROESY experiments. C NMR
spectra were referenced to internal CDCl C 77.0 ppm) or to
external acetone 31.07 ppm). Optical rotations were
measured with a PerkineElmer 241 polarimeter at 22 C. Mass
spectrometric analysis was performed by positive-mode electro-
spray ionization on a Micromass ZabSpec Hybrid Sector-TOF mass
spectrometer.
d
H
H
3
d
2
O. Assignments were made with
1
3
3
(d
1
values of JC-1,H-1 were found to be 160.4e161.2 Hz, which confirms
(d C
-configuration.30
ꢀ
the
b
An acetic acid solution of hexasaccharide 20 was subjected to
hydrogenolysis using Pd/C under hydrogen atmosphere followed
by methanolysis of benzoate groups and a further hydrogenolysis
step in the presence of Pd(OH)
small amounts of residual of benzyl ether to furnish hexasaccharide
, (Scheme 7).
Imidates are recognized to be highly effective glycosylating
derivatives. However, here we experienced success with a thio-
glycoside donor when glycosylations with mono-, di- and trisac-
charide imidate donors failed. A similar experience was reported
during synthesis of Neisseria lipopolysaccharide inner core
oligosaccharides.33
2
on carbon was used to remove
4
.2. 5-Methoxycarbonylpentyl b-D-glucopyranosyl-(1/3)-b-D-
1
glucopyranosyl-(1/3)-
glucopyranosyl-(1/3)-
glucopyranoside (1)
b
-
-
D
-glucopyranosyl-(1/3)-
-glucopyranosyl-(1/3)-
b
-
D
D
-
-
b
D
b-
To a solution of 20 (400 mg, 0.17 mmol) in DCM/CH
3
OH (1:3)
(30 mL) was added Pd/C (40 mg, 10% w/w). The reaction mixture
was stirred for two days under hydrogen atmosphere before it was
filtered, concentrated under reduced pressure. The crude product
was dissolved in CH OH (10 mL) and freshly prepared NaOCH was
3
. Conclusion
3
3
added until the pH¼12 and the reaction was allowed overnight at
þ
3
-O-Benzyl-1,2:5,6-di-O-isoopropylidene-
a
-D
-glucofuranose
2
rt. The solution was neutralized with Amberlite IR-120 H resin,
provides convenient access to selectively protected
b
1,3 linked di
filtered and concentrated under reduced pressure and the result-
ing crude product was purified with column chromatography
(DCM/methanol 5:1) to give the product as white solid. NMR and
MS spectra of it indicated that it was a mixture with the main
component as O-benzyl derivative of expected hexasaccharide 1
so it was subjected to further deprotection. This product (172 mg)
and Pd(OH)2 (20% wt on carbon, 159 mg) were suspended in
glacial acetic acid (5.5 mL) and left stirred under H2 atmosphere
overnight. After 24 h TLC of the reaction mixture (DCM/MeOH/
and trisaccharides 6 and 9 as well as the corresponding imidates 10
and 12. The trisaccharide and disaccharide imidates were unable to
glycosylate the selectively protected di or trisaccharide alcohols 7
and 9. However, the target hexasaccharide 1 could be synthesized
by a 2þ2 and 2þ4 glycosylation sequence. This involved conversion
0
0
0
of 3 -O-benzyl perbenzoylated disaccharide 11 to the 4,6:4 ,6 -di-O-
benzylidene derivative 14 followed by Lewis acid catalyzed reaction
to yield the selectively protected disaccharide ethylthioglycoside
15. Glycosidation of 15 with 5-methoxycarbonylpentanol followed
2
H O/AcOH 12:6:1:0.1) indicated the reaction was complete. The
by a repetitive cycle involving removal of benzyl ether and glyco-
sylation by 15 in 2þ2 and 2þ4 reactions provided a route to
glycoside 1.
catalyst was filtered off using syringe filter (Milipore PVDF
0.45 mm) and rinsed with water. The combined filtrate was
concentrated and purified on RP-HPLC [Phenomex Luna C18(2),
water/acetonitrile 99:1/50:50, 50 min,
lyophilization, compound 1 was obtained as white fluffy solid
t
R
¼24.9 min. After
4
. Experimental data
(
[
d
45 mg, 24%);
R
f
0.24 (DCM/MeOH/H
2
O/AcOH 12:6:1:0.1);
ꢀ
1
ꢀ
4
.1. General methods
a
]
D
ꢁ18.6 (c 1.0, H
2
O); H NMR (700 MHz, D
2
O, 35 C):
4.73e4.76 (m, 3H), 4.73 (d, J¼7.9 Hz, 1H), 4.70 (d, J¼7.9 Hz, 1H),
Solvents used in reactions were purified by successive passage
4.43 (d, J¼8.2 Hz, 1H), 3.84e3.90 (m, 7H), 3.71e3.76 (m, 4H),
3.66e3.71 (m, 7H), 3.65 (s, 3H), 3.61e3.64 (m, 1H), 3.39e3.53 (m,
17H), 3.34e3.38 (m, 1H), 3.31 (dd, J¼9.3, 8.1 Hz, 1H), 2.36 (t,
through columns of alumina and copper under an argon atmo-
sphere. Analytical thin-layer chromatography (TLC) was per-
formed on silica gel 60-F254 (Merck). TLC detection was achieved
by charring with 5% sulfuric acid in ethanol. All commercial re-
agents were used as supplied. Column chromatography used sil-
13
J¼7.4 Hz, 2H), 1.56e1.62 (m, 4H), 1.31e1.36 ppm (m, 2H). C NMR
2
(125 MHz, D O): d 178.6 (C]O), 103.8,103.5, 102.9, 85.4, 85.2, 85.0,
76.9 76.7, 76.5, 74.4, 74.3, 73.9, 71.3, 70.6, 69.2, 69.1, 61.7, 53.1, 34.6,
1
þ
ica gel (SiliCycle, 230e400 mesh, 60 Å). H NMR spectra were
recorded at either 500, 600, or 700 MHz, and are referenced to
29.3, 25.6, 25.0 ppm. HRMS (ESI) calcd (MþNa)
43 74
C H O33Na:
1141.4005. Found: 1141.3991.

H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
101
Scheme 7. (i) NIS, AgOTf, DCM, ꢁ10 ꢀC, 30 min, 89%; (ii) Pd/C, H
, THF-CH
, acetic acid, overnight; NaOCH
OH (1:1), 3 h, 87%; (iii) NIS, AgOTf, DCM, ꢁ20 C, 2 h, 91%; (iv) Pd/C, H
, CH OH, overnight, Pd(OH) /C, H , acetic acid, overnight, 24%.
ꢀ
2
3
2 3
, THF-CH OH (1:1), 3 h, 73%; (v)
NIS, AgOTf, DCM, ꢁ20 ꢀC, 4 h, 87%; (vi) Pd/C, H
2
3
3
2
2
4
.3. 1,2:5,6-Di-O-isopropylidene-3-O-benzyl-
a
-
D
-glucofuranose (2)
solution of satd Na
2
CO
3
and then extracted with EtOAc (3ꢂ75 mL).
After the organic solvent was removed under reduced pressure, a
white pasty material was obtained, which was then dissolved in a
small amount of EtOAc and was kept in fridge. Compound 3 (36 g,
To a solution of 1,2:5,6-di-O-isopropylidene-
a-D-glucofuranose,
(
100 g, 0.38 mol) and benzyl chloride (50.024 g, 45.47 mL,
ꢀ
0
.395 mol) in DMF (300 mL), NaH (14.59 g, 0.608 mol) was added
93.5%) crystalized out as a white crystalline solid: mp 132e134 C;
ꢀ
ꢀ
1
portion-wise over 10 min at 0 C. The reaction mixture was stirred
at rt for 30 min before water (500 mL) was added. The solution was
diluted with EtOAc (2ꢂ200 mL) and washed with water
R
d
f
0.25 (EtOAc); [
a
]
D
þ21.6 (c 1.3, H
2
O); H NMR (700 MHz, D
), 4.82 (d, 2H,
), 3.84 (dd, 1H, J¼12.3,
), 3.73e3.64 (m, 4H, H-
), 3.57 (dd, 1H, J¼9.8, 3.7 Hz, H-2 ), 3.49e3.44 (m,
), 3.41 (ddd,1H, J¼10.0, 5.7, 2.0 Hz, H-4 ), 3.29 (td,1H,
137.7, 137.6, 128.8,
2
O)
7.45e7.34 (m, 10H, AreH), 5.17 (d, 1H, J¼3.7 Hz, H-1
b
J¼6.2 Hz, AreCH
2
), 4.60 (d, 1H, J¼8.0 Hz, H-1
a
(
2ꢂ200 mL). The organic layer was dried (Na
2
SO
4
), filtered,
2.2 Hz, H-5 ), 3.82e3.75 (m, 2H, H-3
b
b
, H-5
a
concentrated, and the resulting crude product was pure enough to
6
(a,b)
a
, H-6(a,b)
b
b
give 2 (130.6 g, 97%) as a yellowish oil, which was carried to the
next step without further purification: R
2H, H-3
J¼8.0, 1.5 Hz, H-2
128.7, 128.4, 128.3, 96.0 (C-1
75.9 (C-4 ), 75.1 (AreCH ), 74.9 (AreCH
), 69.40 (C-5 ), 60.71 (C-6 ), 60.55 (C-6
Na: 293.0996. Found: 293.0988.
a
, H-4
a
b
13
f
0.56 (5:1 hexaneeEtOAc);
); H NMR (500 MHz, CDCl ): 7.38e7.25
a
); C NMR (125 MHz, CDCl
), 92.3 (C-1 ), 84.0 (C-3 ), 81.4 (C-3
b
), 74.0 (C-2 ), 71.6 (C-4
3
): d
ꢀ
1
[
a
]
D
ꢁ24.3 (c 6.8, CHCl
3
3
d
a
b
a
b
),
),
(
m, 5H, AreH), 5.89 (d, 1H, J¼3.7 Hz, H-1), 4.69e4.62 (m, 2H,
b
2
2
a
AreCH
2
), 4.58 (d, 1H, J¼3.7 Hz, H-2), 4.37 (dt, 1H, J¼7.7, 6.0 Hz, H-3),
71.4 (C-2
a
a
,
b
b
a
). HRMS (ESI)
þ
4
3
.17e4.08 (m, 2H, H-5, H-6), 4.03e3.98 (m, 2H, H-4, H-6), 1.49 (s,
calcd (MþNa)
13 18 6
C H O
13
H, CH
3
), 1.42 (s, 3H, CH
):
3
), 1.37 (s, 3H, CH
3
), 1.30 (s, 3H, CH
3
));
C
NMR (125 MHz, CDCl
3
d
137.7, 128.4, 127.9, 127.7, 111.8 ((CH
3
)
2
C),
4.5. 1,2,4,6-Tetra-O-benzoyl-3-O-benzyl-b-D-glucopyranose (4)
1
09.0 ((CH
3
)
2
C), 105.3, 82.7, 81.7, 81.4, 72.6, 72.4, 67.4, 26.9, 26.3,
þ
2
6.3, 25.5. HRMS (ESI) calcd (MþNa)
C
19
H
26
O
6
Na: 373.1622.
To a solution of 3 (30 g, 111 mmol) in pyridine (300 mL) was
ꢀ
Found: 373.1614.
added BzCl (103.2 mL, 0.9 mol) dropwise at 0 C over 1 h. The re-
action mixture was stirred for additional 2 h at room temperature
4.4. 3-O-Benzyl-
a/b
-D
-glucopyranose (3)
2
before it was quenched with ice/H O (500 g) and stirring was
continued for another 1 h. The formed precipitate was filtered,
A solution of 6 M HCl (25 mL) was added to a solution of com-
washed with H
2
O and then recrystallized from EtOAc/Hexane to
ꢀ
pound 2 (50 g, 0.143 mol) in dioxane (100 mL) and stirred overnight
at room temperature. Dichloromethane (DCM) (50 mL) was added
to the reaction mixture and the yellowish organic layer was sepa-
rated and discarded. The aqueous layer was neutralized by adding a
give 4 (70 g, 92%) as a white crystalline solid: mp¼131.50 C; R
f
0.38
ꢀ
1
(EtOAc/hexane 1:3); [
a
]
D
þ1.3 (c 1.33, CHCl
3
); H NMR (500 MHz,
CDCl
3
)
d
8.07e8.03 (m, 7H, AreH), 7.63e7.55 (m, 4H, AreH),
7.50e7.39 (m, 9H, AreH), 7.14e7.03 (m, 5H, AreH), 6.23 (d, 1H,

102
H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
þ
J¼7.7 Hz, H-1), 5.80e5.74 (m, 2H, H-2, H-3), 4.70e4.65 (m, 3H,
AreCH , H-6 ), 4.31 (ddd, 1H,
), 4.49 (dd, 1H, J¼12.2, 5.1 Hz, H-6
J¼9.6, 5.1, 3.1 Hz, H-5), 4.25 (t, 1H, J¼8.7 Hz, H-4); C NMR
126 MHz, CDCl 166.2, 165.0, 164.8, 137.0, 133.7, 133.5, 133.4,
33.0, 130.2, 129.9, 129.8, 129.6, 129.2, 129.2, 128.6, 128.5, 128.5,
28.3, 128.2, 128.1, 127.8, 92.6, 79.2, 77.3, 77.1, 76.8, 74.3, 73.1, 72.1,
66.11, 63.20, 26.67, 26.57, 25.97, 25.07. HRMS (ESI) calcd (MþNa)
2
a
b
39 42
C H O14Na: 757.2467. Found: 757.2457.
13
0
0
0
(
1
1
3
)
d
4.8. 2 ,4 ,6 -Tri-O-benzoyl-
b-
D-glucopyranosyl-(1/3)-1,2:5,6-di-O-
isopropylidene-a-D-glucofuranose (7)
þ
7
0.3, 62.9. HRMS (ESI) calcd (MþNa)
C
41
H
34
O10Na: 709.2044.
To a solution of 6 (20 g, 24.2 mmol) in CH
3
OH/DCM (4:1)
Found: 709.2048.
(100 mL) was added Pd/C (1 g, 5% w/w). The reaction mixture was
stirred overnight under hydrogen atmosphere before it was
filtered, concentrated under reduced pressure and the crude mass
4.6. 2,4,6-Tri-O-benzoyl-3-O-benzyl-a-D-glucopyranosyl
was recrystallized from EtOAc/hexane to give 7 (16.6 g, 93%) as a
trichloroacetimidate (5)
ꢀ
crystalline white solid: mp 241e243 C; R
f
0.29 (EtOAc/hexane 1:2);
8.10e7.99 (m,
H, AreH), 7.63e7.53 (m, 3H, AreH), 7.51e7.37 (m, 6H, AreH), 5.55
ꢀ
1
[
6
a
]
D
ꢁ4.8 (c 1.4, CHCl
3
); H NMR (600 MHz, CDCl
3
)
d
To a solution of 4 (30 g, 43.7 mmol) in DCM/THF (1:10) (200 mL)
was added CH NH (30 mL, 33 wt% in absolute EtOH) and the re-
3
2
0
(
7
H-6
d,1H, J¼3.7 Hz, H-1), 5.44 (t,1H, J¼9.6 Hz, H-4 ), 5.22 (dd,1H, J¼9.1,
action mixture was stirred for 4 h at room temperature. The reac-
tion was quenched with 1 M HCl (100 mL), diluted with DCM
0
0
.7 Hz, H-2 ), 4.88 (d, 1H, J¼7.7 Hz, H-1 ), 4.66 (dd, 1H, J¼12.1, 3.1 Hz,
0
0
a
), 4.48 (dd, 1H, J¼12.1, 5.3 Hz, H-6 ), 4.41 (d, 1H, J¼3.7 Hz, H-
b
(
100 mL) and the organic layer was separated and the solvent was
2
1
), 4.36 (q, 1H, J¼5.9 Hz, H-5), 4.34 (d, 1H, J¼3.2 Hz, H-3), 4.24 (dd,
removed under reduced pressure. The resulting crude mass (25.5 g)
was dissolved in dry DCM (100 mL), trichloroacetonitrile (87.6 mL)
and DBU (0.5 mL) were added and the reaction mixture was stirred
for 30 min. The mixture was concentrated under reduced pressure
and the resulting crude product was purified with column chro-
0
H, J¼5.9, 3.2 Hz, H-4), 4.14 (t, 1H, J¼8.9 Hz, H-3 ), 4.05 (ddd, 1H,
0
J¼9.9, 5.2, 3.1 Hz, H-5 ), 4.01 (dd, 1H, J¼8.7, 6.5 Hz, H-6
a
), 3.96 (dd,
), 1.37 (s, 3H, CH ), 1.21 (s,
3 C
); C NMR (150.86 MHz, CDCl , d ) 166.2
1
3
H, J¼8.7, 5.6 Hz, H-6
b
), 1.44 (s, 3H, CH
3
3
13
H, CH ), 1.17 (s, 3H, CH
3
3
(
1
C]O), 166.1 (C]O), 165.8 (C]O), 133.6, 133.2, 129.9, 129.8, 129.7,
29.5, 129.3, 129.0, 128.6, 128.5, 128.4, 111.9, 108.7, 105.0, 99.5, 82.9,
1.0, 80.4, 74.6, 73.9, 73.0, 72.3, 72.2, 66.2, 63.2, 26.7, 26.6, 26.1, 25.1.
matography (EtOAc/hexane 1:3) to give 5 (26.7 g, 84%) as an
ꢀ
amorphous solid: R
f
0.54 (EtOAc/hexane 3:1); [
); H NMR (500 MHz, CDCl
J¼7.3 Hz, AreH), 7.68e7.60 (m, 3H, AreH), 7.60e7.55 (m, 6H, AreH),
.53e6.99 (m, 5H, AreH), 6.76 (d, 1H, J¼3.7 Hz, H-1), 5.72 (t, 1H,
J¼9.7 Hz, H-4), 5.55 (dd, 1H, J¼9.7, 3.7 Hz, H-2), 4.72 (ABq, 2H,
), 4.54e4.51 (m,
H, H-5), 4.48 (t, 1H, J¼9.7 Hz, H-3), 4.43 (dd, 1H, J¼12.2, 5.0 Hz, H-
a
]
D
þ113.3 (c 1.20,
8
1
CHCl
3
3
) d 8.61 (s, 1H, NH), 8.06 (q, 6H,
þ
HRMS (ESI) calcd (MþNa)
36 30 9 3
C H O NCl Na: 748.0878. Found:
748.0885.
7
0
0
00 00
00
4
(
.9. 2 ,4 ,6 -Tri-O-benzoyl-3 -O-benzyl-
b
-
D
-glucopyranosyl-
-glucopyranosyl-(1/3)-1,2:5,6-
a-D-glucofuranose (8)
J¼11.4 Hz, BnCH
2
), 4.64 (dd, 1H, J¼12.2, 2.5 Hz, H-6
a
0
0
0
1/3)-2 ,4 ,6 -tri-O-benzoyl-
di-O-isopropylidene-
b-D
1
6
1
3
b
); C NMR (126 MHz, CDCl 166.1 (CO), 165.3 (CO), 165.0 (CO),
3
) d
1
60.4 (C]NH), 137.2, 133.5, 133.5, 133.1, 129.9, 129.8, 129.8, 129.7,
To a solution of 5 (8.9 g, 12.25 mmol) and 7 (10 g, 13.6 mmol) in
DCM (100 mL) was added molecular sieves 4 Å (10 g). After the
1
29.2, 129.2, 128.5, 128.5, 128.4, 128.2, 128.1, 127.8, 93.5, 90.9, 76.6,
7
C
4.9, 72.47, 70.8, 70.2, 62.7. HRMS (ESI) calcd (MþNa)þ
solution was stirred for 30 min at rt, the reaction was cooled to
H
36 30
O
9
NCl
3
Na: 748.0878. Found: 748.0885.
ꢀ
0
C, TMSOTf (100
mL, 0.56 mmol) was added and the reaction
mixture was stirred for 4 h. After neutralization with Et
solution was concentrated under reduced pressure and the crude
3
N, the
0
0
0
0
4
.7. 2 ,4 ,6 -Tri-O-benzoyl-3 -O-benzyl-
b
-D
-glucopyranosyl-(1/3)-
1
,2:5,6-di-O-isopropylidene-
a-D
-glucofuranose (6)
mass was recrystallized from EtOAc/hexane to afford 8 (14.5 g,
9
1%) as an amorphous white powder: R
f
0.35 (EtOAc/hexane 1:2);
ꢀ
1
To a solution of 5 (20 g, 27.5 mmol) and 1,2:5,6-di-O-iso-
propylidene- -glucofuranose (7.9 g, 30.3 mmol) in DCM (100 mL)
was added molecular sieves 4 Å (10 g). After the solution was
stirred for 30 min, TMSOTf (250 L, 1.4 mmol) was added and the
reaction mixture was stirred for 45 min at room temperature. After
neutralization with Et N, the solution was concentrated under
[a
]
D
ꢁ29.0 (c 1.0, CHCl
3
); H NMR (500 MHz, CDCl 8.08e8.02
3
) d
a
-D
(m, 3H, AreH), 7.98e7.95 (m, 2H, AreH), 7.92e7.87 (m, 2H, AreH),
7.81e7.76 (m, 2H, AreH), 7.75e7.65 (m, 1H, AreH), 7.63e7.49 (m,
7H, AreH), 7.49e7.44 (m, 1H, AreH), 7.44e7.24 (m, 12H, AreH),
7.05e6.98 (m, 1H, AreH), 6.92 (t, J¼7.6 Hz, 2H, AreH), 6.87e6.77
(m, 2H, AreH), 5.50 (t, J¼9.4 Hz, 1H), 5.34e5.27 (m, 1H), 5.27e5.21
(m, 1H), 4.95 (d, J¼7.8 Hz, 1H), 4.71 (d, J¼7.4 Hz, 1H), 4.64 (dd,
J¼12.1, 3.6 Hz, 1H), 4.45 (ddd, J¼11.2, 9.7, 5.2 Hz, 4H), 4.41 (d,
J¼5.1 Hz, 1H), 4.30 (q, J¼5.9 Hz, 1H), 4.23 (d, J¼3.2 Hz, 1H), 4.18
(ddt, J¼9.7, 5.9, 3.4 Hz, 3H), 4.11e3.96 (m, 4H), 3.90 (td, J¼8.9,
m
3
reduced pressure and the crude mass was recrystallized from
EtOAc/hexane to afford 6 (20.2 g, 89%) as a crystalline white solid:
ꢀ
ꢀ
mp 197e199 C; R
f
0.42 (EtOAc/hexane 1:2); [
a]
D
ꢁ3.6 (c 1.0,
1
1
CHCl
3
); H NMR (500 MHz, CDCl
3
)
d
H NMR (700 MHz, CDCl
3
)
13
d
8.06e7.99 (m, 6H, AreH), 1.26e1.23 (m, 3H), 7.64e7.57 (m, 2H,
4.8 Hz, 3H), 1.42 (s, 3H), 1.38 (s, 3H), 1.26 (s, 3H), 1.10 (s, 3H);
C
AreH), 7.54 (ddt, 1H, J¼8.8, 7.4, 1.3 Hz, AreH), 7.51e7.47 (m, 2H,
NMR (126 MHz, CDCl 166.2 (C]O), 166.0 (C]O), 165.0 (C]O),
3
) d
AreH), 7.46e7.42 (m, 2H, AreH), 7.41e7.37 (m, 2H, AreH),
164.9 (C]O), 164.8 (C]O), 163.9 (C]O), 137.0, 133.6, 133.4, 133.3,
133.2, 133.1, 133.0, 129.9, 129.8, 129.76, 129.71, 129.68, 129.63,
129.57, 129.53, 129.50, 129.3, 129.2, 111.8, 108.5, 104.8, 100.8, 99.44,
82.5, 80.9, 80.5, 79.6, 77.7, 73.8, 73.5, 72.9, 72.4, 72.1, 71.2, 70.0,
7
.08e7.04 (m, 1H, AreH), 7.01 (d, 4H, J¼5.0 Hz, AreH), 5.60 (dd, 1H,
0
J¼9.9, 9.0 Hz, C-4 ), 5.46 (d, 1H, J¼3.7 Hz, H-1), 5.38 (dd, 1H, J¼9.1,
0
0
7
H-6
H-6
.7 Hz, H-2 ), 4.81 (d,1H, J¼7.7 Hz, H-1 ), 4.61 (dd,1H, J¼12.0, 3.4 Hz,
0
0
þ
a
), 4.59 (d, 2H, J¼1.0 Hz, AreCH
2
), 4.45 (dd, 1H, J¼12.0, 5.3 Hz,
66.1, 63.6, 63.4, 26.7, 26.6, 25.9, 25.0. HRMS (ESI) calcd (MþNa)
b
), 4.36 (dt, 1H, J¼6.5, 5.6 Hz, H-5), 4.31 (d, 1H, J¼3.7 Hz, H-2),
73 70
C H O22Na: 1321.4251. Found: 1321.4238.
4
1
.28 (d, 1H, J¼3.2 Hz, H-3), 4.23 (dd, 1H, J¼5.4, 3.1 Hz, H-4), 4.08 (t,
0
0
00 00 00
0 0 0
b-D-glucopyranosyl-(1/3)-2 ,4 ,6 -
H, J¼9.1 Hz, H-3 ), 4.04e3.99 (m, 2H, H-5 , H-6
), 1.42 (s, 3H, CH ), 1.37 (s, 3H, CH
); C NMR (126 MHz, CDCl
a
), 3.96 (dd, 1H,
4.10. 2 ,4 ,6 -Tri-O-benzoyl-
tri-O-benzoyl- -glucopyranosyl-(1/3)-1,2:5,6-di-O-
isopropylidene- -glucofuranose (9)
J¼8.7, 5.8 Hz, H-6
b
3
3
d
), 1.24 (s, 3H,
166.2, 165.0,
b-D
a-D
13
CH )1.12 (s, 3H, CH
3
3
3
)
1
1
8
64.6, 137.1, 133.5, 133.5, 133.01, 129.9, 129.7, 129.7, 129.6, 129.4,
29.2, 128.6, 128.5, 128.4, 128.2, 128.0, 127.7, 111.8, 108.6, 104.9, 99.8,
2.7, 81.1, 80.4, 79.1, 77.2, 77.0, 76.8, 73.8, 73.33, 73.02, 72.48, 70.92,
To a solution of 8 (1 g, 0.8 mmol) in CH
3
OH/DCM (2:1) (30 mL)
was added Pd/C (50 mg, 5% w/w). The reaction mixture was stirred

H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
103
overnight under hydrogen atmosphere before it was filtered,
concentrated under reduced pressure and the crude mass was
(C]O), 163.8 (C]O), 160.2 (C]O), 136.9, 133.7, 133.5, 133.4, 133.3,
133.2, 133.1, 133.0, 132.9, 130.0, 129.9, 129.8, 129.76, 129.73, 129.68,
129.66, 129.59, 129.56, 129.47, 129.38, 129.36, 129.13, 128.9, 128.7,
128.5, 128.4, 128.3, 128.3, 128.2, 128.0, 127.8, 127.5, 101.8, 101.0, 93.0,
recrystallized from EtOAc/hexane to give 9 (0.83 g, 89%) as amor-
ꢀ
phous white powder: R
f
0.3 (EtOAc/hexane 1:2); [
a
]
D
ꢁ39.7 (c 1.4,
1
1
CHCl
3
); H NMR (500 MHz, CDCl
3
)
d
H NMR (500 MHz, CDCl
3
)
90.8, 79.4, 77.9, 76.4, 73.7, 73.6, 73.1, 72.9, 72.3, 71.9, 71.2, 70.7, 68.5,
þ
d
8.09e8.05 (m, 2H, AreH), 8.05e7.92 (m, 8H, AreH), 7.88e7.82 (m,
H, AreH), 7.73e7.67 (m, 1H, AreH), 7.62e7.51 (m, 7H, AreH), 7.40
63.8, 63.6, 62.8. HRMS (ESI) calcd (MþNa)
90 74 3
C H O25NCl Na:
2
1696.3508. Found: 1696.3527.
(
td, J¼7.7, 1.9 Hz, 8H, AreH), 7.36e7.31 (m, 2H, AreH), 5.49 (t,
J¼9.4 Hz, 1H), 5.36 (dd, J¼8.9, 7.5 Hz, 1H), 5.27 (d, J¼3.7 Hz, 1H),
.11e5.00 (m, 2H), 4.93 (d, J¼7.7 Hz, 1H), 4.71 (d, J¼7.9 Hz, 1H), 4.63
dd, J¼12.1, 3.4 Hz, 1H), 4.46 (dd, J¼10.2, 7.5 Hz, 2H), 4.31 (q,
0
0
0
0
4.12. 2 ,4 ,6 -Tri-O-benzoyl-3 -O-benzyl-
b-D-glucopyranosyl-
5
(
(1/3)-2,4,6-tri-O-benzoyl- -glucopyranosyl benzoate (11)
b-D
J¼5.8 Hz, 1H), 4.27e4.17 (m, 4H), 4.07 (dt, J¼11.8, 6.2 Hz, 3H), 4.00
A solution of 6 (5 g, 6.1 mmol) in dioxane/6 M HCl (4:1) (50 mL)
was stirred at room temperature for 17 h before the solution was
diluted with H
and the organic layer was separated, washed with satd Na
(50 mL), satd NaCl (50 mL), dried over anhydrous Na SO and the
(
(
(
(
dd, J¼8.7, 6.6 Hz, 1H), 3.91 (dd, J¼9.0, 5.9 Hz, 3H), 1.42 (s, 3H), 1.38
13
s, 3H), 1.26 (s, 3H), 1.11 (s, 3H); C NMR (126 MHz, CDCl
3
)
d
166.4
2
O (50 mL). DCM (100 mL) was added to the mixture
C]O), 166.1 (C]O), 165.9 (C]O), 165.8 (C]O), 164.9 (C]O), 164.0
C]O), 133.8, 133.5, 133.4, 133.3, 133.2, 133.1, 130.0, 129.8, 129.8,
2
CO
3
2
4
1
29.7, 129.6, 129.6, 129.5, 129.4, 129.3, 129.2, 129.1, 128.9, 128.8,
solvent was removed under reduced pressure to give sticky white
mass. The crude solid was dissolved in pyridine (40 mL) and BzCl
(5.6 mL, 48.5 mmol) was added dropwise at 0 C over 10 min. The
128.6, 128.5, 128.4, 128.3, 128.2, 111.8, 108.6, 104.8, 100.4, 99.5, 82.6,
ꢀ
8
6
1.0, 80.4, 77.6, 74.8, 74.0, 73.5, 72.9, 72.5, 72.4, 71.8, 69.8, 66.1, 63.6,
þ
3.3, 26.7, 26.6, 25.9, 25.0. HRMS (ESI) calcd (MþNa)
C
66
H
64
O22Na:
reaction mixture was stirred for additional 2 h at room temperature
1231.3781. Found: 1231.3762.
before it was quenched with ice/H
continued for another 1 h. The formed precipitate was filtered,
washed with H O, dissolved in DCM (50 mL) and washed with satd
NaCl (50 mL) before was dried over anhydrous Na SO and the
2
O (100 g) and stirring was
0
0
00 00
0
00
4.11. 2 ,4 ,6 -Tri-O-benzoyl-3 -O-benzyl-
b
-
D
-glucopyranosyl-
-glucopyranosyl-(1/3)-2,4,6-tri-
-glucopyranosyl trichloroacetimidate (10)
2
0
0
(
1/3)-2 ,4 ,6 -tri-O-benzoyl-
b-
D
2
4
O-benzoyl-
b-
D
solvent was removed under reduced pressure to give 11 as white
ꢀ
solid (5.8, 82%): R
f
0.38 (EtOAc/hexane 1:3); [
a
]
D
ꢁ48.6 (c 1.5,
ꢀ
1
A solution of 8 (5 g, 3.84 mmol) in dioxane/6 M HCl (4:1)
CHCl ); mp 62.0e64.0 C; H NMR (500 MHz, CDCl
3
3
)
d
8.16 (d,
(
100 mL) was stirred at room temperature for 17 h before the so-
J¼1.3 Hz, 1H, AreH), 8.14 (d, J¼1.3 Hz, 1H, AreH), 8.12 (d, J¼1.2 Hz,
1H, AreH), 8.11 (d, J¼1.4 Hz, 1H, AreH), 8.03 (dd, J¼2.8, 1.2 Hz, 2H,
AreH), 8.02e8.01 (m, 3H, AreH), 8.00 (d, J¼1.3 Hz, 1H, AreH),
7.95e7.93 (m, 1H, AreH), 7.93 (t, J¼1.4 Hz, 2H, AreH), 7.91 (d,
J¼1.5 Hz, 1H, AreH), 7.61e7.29 (m, 18H, AreH), 7.20 (dd, J¼8.3,
7.5 Hz, 2H, AreH), 7.04e6.98 (m, 1H, AreH), 6.92 (t, J¼7.6 Hz, 2H,
AreH), 6.85e6.80 (m, 2H, AreH), 6.76 (d, J¼3.8 Hz, 1H, AreH), 5.64
(t, J¼9.7 Hz, 1H), 5.43 (dd, J¼9.9, 3.8 Hz, 1H), 5.35 (dd, J¼9.3, 7.9 Hz,
1H), 5.29 (dd, J¼9.8, 9.0 Hz, 1H), 5.07 (d, J¼7.9 Hz, 1H), 4.79 (t,
J¼9.6 Hz, 1H), 4.68e4.60 (m, 1H), 4.49e4.37 (m, 2H), 4.29 (dd,
J¼11.8, 3.6 Hz, 4H), 4.08 (ddd, J¼9.8, 6.2, 3.6 Hz, 1H), 3.97 (dd,
lution with diluted with H
the mixture and the organic layer was separated, washed with satd
Na CO (100 mL), satd NaCl (100 mL), dried over anhydrous Na SO
4
and the solvent was removed under reduced pressure to give
amorphous solid (3.5 g). The crude solid was dissolved in pyridine
2
O (100 mL). DCM (100 mL) was added to
2
3
2
ꢀ
(
20 mL) and BzCl (3.6 mL, 30.8 mmol) was added dropwise at 0 C
over 10 min. The reaction mixture was stirred for additional 2 h at
room temperature before it was quenched with ice/H O (100 g) and
stirring was continued for another 1 h. The formed precipitate was
filtered, washed with H O, dissolved in DCM (50 mL) and washed
with satd NaCl (50 mL) before was dried over anhydrous Na SO
and the solvent was removed under reduced pressure. The formed
white solid was dissolved in THF/DCM (4:1) (50 mL) and CH NH
7.5 mL, 33 wt% in absolute ethanol) was added and the reaction
mixture was stirred for 3 h before it was neutralized with 1 M HCl
25 mL), diluted with DCM (100 mL), the organic layer was sepa-
rated, dried over anhydrous Na SO and the solvent was removed
under reduced pressure. The resulting crude mass was dissolved in
dry DCM (40 mL), trichloroacetonitrile (7 mL) and DBU (100 L)
2
2
13
2
4
J¼11.9, 6.3 Hz, 1H), 3.93 (t, J¼9.1 Hz, 2H); C NMR (126 MHz, CDCl
3
)
d
166.2 (C]O), 166.1 (C]O), 163.0 (2C]O), 164.7 (C]O), 164.6 (C]
3
2
O), 164.3 (C]O), 136.9, 133.7, 133.6, 133.5, 133.4, 133.3, 133.2, 133.1,
133.0, 130.1, 129.8, 129.8, 129.8, 129.7, 129.6, 129.5, 129.4, 129.2,
129.2, 129.1, 128.9, 128.7, 128.6, 128.5, 128.4, 128.4, 128.3, 128.2,
(
(
128.1, 127.9, 127.6, 101.4, 90.0, 79.4, 76.0, 73.7, 73.2, 72.7, 72.1, 71.16,
þ
2
4
70.4, 69.1, 63.6, 62.9. HRMS (ESI) calcd (MþNa)
68 56
C H O18Na:
1183.3359. Found: 1183.3345.
m
0
0
0
0
were added and the reaction mixture was stirred for 30 min. The
mixture was concentrated under reduced pressure and the result-
ing crude product was purified with column chromatography
4.13. 2 ,4 ,6 -Tri-O-benzoyl-3 -O-benzyl-
b-D
-glucopyranosyl-
(1/3)-2,4,6-tri-O-benzoyl-
trichloroacetimidate (12)
b-D-glucopyranosyl
(
0
EtOAc/hexane 1:1) to give 10 (5 g, 78%) as an amorphous solid: R
f
ꢀ
1
.39 (EtOAc/hexane 1:1); [
a
]
D
ꢁ20.3 (c 1.2, CHCl
3
); H NMR
To a solution of 11 (2.5 g, 2.2 mmol) in THF/DCM (4:1) (25 mL)
NH (10 mL, 33 wt% in absolute ethanol) was added. The re-
(
500 MHz, CDCl
3
)
d
8.55 (s, 1H, NH), 8.12 (d, J¼7.7 Hz, 2H, AreH),
CH
3
2
8
.04 (t, J¼7.0 Hz, 6H, AreH), 7.97 (d, J¼7.7 Hz, 2H, AreH), 7.91e7.83
action was stirred for 3 h before it was neutralized with 1 M HCl
(25 mL), diluted with DCM (50 mL), the organic layer was sepa-
(
m, 4H, AreH), 7.69 (d, J¼7.7 Hz, 2H, AreH), 7.64e7.18 (m, 28H,
AreH), 6.99 (t, J¼7.4 Hz, 1H, AreH), 6.89 (t, J¼7.6 Hz, 2H, AreH),
.77 (d, J¼7.5 Hz, 2H, AreH), 6.69 (d, J¼3.7 Hz, 1H, AreH), 5.57 (t,
J¼9.8 Hz, 1H), 5.28 (t, J¼8.7 Hz, 1H), 5.21 (ddt, J¼24.7, 11.2, 5.0 Hz,
H), 5.01 (d, J¼8.0 Hz, 1H), 4.69 (dd, J¼8.8, 4.1 Hz, 1H), 4.65 (d,
J¼4.3 Hz, 1H), 4.63 (d, J¼2.8 Hz, 1H), 4.56 (dt, J¼10.4, 4.0 Hz, 21H),
rated, dried over anhydrous Na
under reduced pressure. The resulting crude mass was dissolved in
dry DCM (30 mL), trichloroacetonitrile (5 mL) and DBU (100 L)
2 4
SO and the solvent was removed
6
m
4
were added and the reaction solution was stirred for 30 min. The
mixture was concentrated under reduced pressure and the result-
ing crude product was purified with column chromatography
4
.43 (dd, J¼12.0, 5.2 Hz, 2H), 4.34 (dd, J¼11.8, 6.5 Hz, 4H), 4.13 (ddd,
J¼25.2, 11.3, 5.4 Hz, 2H), 4.01 (dd, J¼11.9, 5.6 Hz, 1H), 3.92 (dd,
(EtOAc/hexane 1:1) to give 12 (2.1 g, 81%) as an amorphous solid: R
f
ꢀ
1
J¼12.0, 6.7 Hz, 1H), 3.74 (dt, J¼9.7, 4.8 Hz, 1H), 3.68 (t, J¼9.1 Hz,
0.4 (EtOAc/hexane 1:1); [
(500 MHz, CDCl
a
]
D
3
þ4.82 (c 1.0, CHCl ); H NMR
13
1
H); C NMR (126 MHz, CDCl
3
)
d
166.1 (C]O), 166.0 (C]O), 165.9
3
)
d
8.53 (s, 1H, NH), 8.15e8.10 (m, 2H, AreH),
(
C]O), 165.0 (C]O), 164.9 (C]O), 164.8 (C]O), 164.7 (C]O), 164.5
8.06e8.01 (m, 4H, AreH), 7.96 (ddd, J¼10.0, 8.2, 1.5 Hz, 4H, AreH),

104
H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
7
.74e7.67 (m, 1H, AreH), 7.62e7.39 (m, 15H, AreH), 7.34 (t,
66.2, 65.3. HRMS (ESI) calcd (MþNa)þ
54 48
C H O14Na: 943.2936.
J¼7.7 Hz, 2H, AreH), 7.19 (t, J¼7.7 Hz, 2H, AreH), 7.01 (t, J¼7.4 Hz,
Found: 943.2935.
1
H, AreH), 6.92 (t, J¼7.6 Hz, 2H, AreH), 6.82 (d, J¼7.2 Hz, 2H,
0
0
0
0
AreH), 6.69 (d, J¼3.6 Hz, 1H), 5.61 (t, J¼9.8 Hz, 1H), 5.36e5.29 (m,
4.16. Ethylthio 2 -O-benzoyl-3 -O-benzyl-4 ,6 -O-benzylidene-
b-
D-
2
1
4
6
d
H), 5.24 (t, J¼9.4 Hz, 1H), 5.04 (d, J¼8.0 Hz, 1H), 4.70 (t, J¼9.6 Hz,
H), 4.63 (dd, J¼12.3, 2.7 Hz, 1H), 4.54 (ddd, J¼10.5, 5.1, 2.8 Hz, 1H),
.46e4.37 (m, 3H), 4.33 (dd, J¼12.0, 3.0 Hz, 1H), 4.06 (ddd, J¼9.9,
glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-benzylidene-
glucopyranoside (15)
b-D-
13
.9, 3.0 Hz, 1H), 3.94e3.86 (m, 2H); C NMR (126 MHz, CDCl
3
)
To a solution of 14 (3 g, 3.3 mmol) in DCM (30 mL) and crushed
4 Å molecular sieves (3 g) was added EtSH (0.4 mL, 4.9 mmol). The
166.2 (C]O), 166.1 (C]O), 165.0 (C]O), 164.9 (C]O), 164.7 (C]
O), 164.6 (C]O), 160.2 (C]NH), 136.9, 133.6, 133.5, 133.4, 133.3,
33.1, 132.9, 130.0, 129.9, 129.8, 129.7, 129.6, 129.5, 129.4, 129.3,
29.2, 128.9, 128.6, 128.5, 128.4, 128.3, 128.2, 128.1, 128.0, 127.9,
27.5, 101.5, 93.1, 90.7, 79.3, 76.0, 73.5, 73.1, 72.9, 72.3, 71.0, 70.7,
reaction mixture was stirred for 30 min at room temperature and
ꢀ
1
1
1
then cooled to 0 C before BF
3
$Et
2
O (1.6 mL, 13.2 mmol) was added
dropwise over 10 min. The reaction mixture was stirred overnight
before it was quenched with satd aq NaHCO soln (30 mL), the
3
þ
6
8.5, 63.7, 62.8. HRMS (ESI) calcd (MþNa)
C
H
63 52
O17NCl
3
Na:
organic layer was separated and concentrated to a yellow syrup
under reduced pressure. Column chromatography in (EtOAc/hex-
1222.2193. Found: 1222.2192.
ane 1:3) gave 15 (2.3 g, 82%) as a white powder after concentration:
0
ꢀ
4
.14. 3 -O-Benzyl-
b
-D
-glucopyranosyl-(1/3)-2-O-benzoyl-
b-
D-
R
f
0.39 (EtOAc/hexane 1:3);
[a
]
D
þ0.7 (c 1.0, CHCl
3
); mp
ꢀ
1
glucopyranosyl benzoate (13)
192.0e194.0 C; H NMR (700 MHz, CDCl ) d
3
8.17 (d, J¼7.0 Hz, 2H,
AreH), 7.86e7.83 (m, 2H, AreH), 7.64 (dd, J¼9.0, 7.1 Hz, 4H, AreH),
7.60e7.48 (m, 5H, AreH), 7.48e7.34 (m, 6H, AreH), 7.30 (t, J¼7.7 Hz,
1H, AreH), 7.15e7.12 (m, 1H, AreH), 7.11e7.05 (m, 4H, AreH), 5.61
(s, 1H), 5.37 (t, J¼9.5 Hz, 1H), 5.35 (s, 1H), 5.31 (t, J¼6.9 Hz, 1H), 4.94
(d, J¼6.9 Hz, 1H), 4.74, 4.62 (dd, J¼12.0 Hz, 2H), 4.61 (d, J¼9.5 Hz,
1H), 4.43 (dd, J¼10.5, 4.8 Hz, 1H), 4.28e4.22 (m, 2H), 3.94 (t,
J¼9.3 Hz, 1H), 3.85 (dt, J¼14.0, 9.8 Hz, 1H), 3.78e3.70 (m, 1H), 3.62
3
To a solution of 11 (2 g, 1.72 mmol) in DCM/CH OH (1:2)
30 mL) was added freshly prepared NaOCH (46.5 mg, 0.86 mmol)
3
(
and the reaction mixture was stirred for 1 h and then was
þ
neutralized with Amberlite IR-120 H resin, filtered and concen-
trated under reduced pressure. Column chromatography in
EtOAc/hexane 2:1) gave the title compound, 13, as waxy white
(
ꢀ
solid (0.92 g, 72%): R
f
0.19 (EtOAc/hexane 2:1); [
); H NMR (500 MHz, CDCl
AreH), 7.66 (dd, J¼8.4, 1.4 Hz, 2H, AreH), 7.61e7.55 (m, 3H, AreH),
.50e7.42 (m, 3H, AreH), 7.38 (tt, J¼7.4, 1.3 Hz, 1H, AreH), 7.24
dd, J¼8.3, 7.4 Hz, 2H, AreH), 7.14e7.04 (m, 7H, AreH), 6.59 (d,
a
]
D
þ36.8 (c 1.3,
(td, J¼9.7, 4.9 Hz, 1H), 3.46 (td, J¼9.8, 4.9 Hz, 1H), 2.69 (tp, J¼15.0,
1
13
CHCl
3
3
)
d
8.00 (dd, J¼8.3, 1.3 Hz, 2H,
7.5 Hz, 2H, SCH
2
), 1.20 (t, J¼7.5 Hz, 3H, SCH
2
CH
3
); C NMR
3
(126 MHz, CDCl ) d 164.8 (C]O), 164.7 (C]O), 137.8, 137.3, 137.2,
7
(
133.8, 133.0, 132.7, 130.2, 129.8, 129.7, 129.5, 129.4, 129.3, 128.9,
128.5,128.3,128.2,128.1,128.1,127.8,127.4,126.2,126.0,101.6,101.0,
100.6, 84.3, 80.7, 79.4, 79.0, 78.5, 73.8, 73.5, 72.1, 71.1, 68.7, 68.6,
J¼3.8 Hz, 1H), 5.28 (dd, J¼9.3, 7.8 Hz, 1H), 5.24 (dd, J¼9.8, 3.8 Hz,
1
8
H), 4.91 (d, J¼7.8 Hz, 1H), 4.61 (d, J¼11.5 Hz, 2H), 4.29 (dd, J¼9.8,
.2 Hz, 1H), 4.07 (dd, J¼12.1, 2.6 Hz, 1H), 4.01e3.83 (m, 7H), 3.66 (t,
66.0, 23.9, 14.7. HRMS (ESI) calcd (MþNa)þ
49 48
C H O12SNa:
860.2866. Found: 860.2857.
13
J¼9.1 Hz, 1H); C NMR (126 MHz, CDCl
3
) d 165.4 (C]O), 164.9
0
0
0
0
(
1
1
6
C]O), 164.6 (C]O), 137.7, 133.7, 133.5, 133.1, 132.9, 130.2, 129.9,
29.6, 129.5, 129.2, 129.0, 128.8, 128.6, 128.4, 128.3, 128.2, 128.1,
4.17. 5-Methoxycarbonylpentyl 2 -O-benzoyl-3 -O-benzyl-4 ,6 -O-
benzylidene-
b
-
-
D
-glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-
-glucopyranoside (16)
28.0, 127.7, 101.3, 90.2, 82.1, 80.9, 76.2, 74.7, 73.9, 73.6, 71.5, 70.0,
benzylidene-
b
D
8.5, 61.7, 61.5. HRMS (ESI) calcd (MþNa)þ
40 40
C H O14Na: 767.2310.
Found: 767.2298.
To a solution of 15 (3 g, 3.5 mmol) and methyl 6-
hydroxyhexanoate (600 mg, 4.2 mmol) in dry DCM (30 mL) was
added crushed 4 Å molecular sieves (3 g) and the mixture was
stirred for 30 min at rt. NIS (94 mg, 4.2 mmol) and AgOTf (51 mg,
0
0
0
0
4
.15. 2 -O-Benzoyl-3 -O-benzyl-4 ,6 -O-benzylidene-
b
-D
-
glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-benzylidene-
glucopyranosyl benzoate (14)
b-D-
ꢀ
0.2 mmol) were added to the mixture after it was cooled to ꢁ10 C
and was stirred for additional 30 min at the same temperature.
To a solution of 13 (3 g, 4.02 mmol) in acetonitrile (40 mL) was
added benzaldehyde dimethylacetal (1.5 mL, 9.7 mmol) followed
by p-toluenesulfonic acid (100 mg). The solution was stirred for
3
The reaction mixture was neutralized with Et N (0.5 mL), filtered
and concentrated to a colorless syrup under reduced pressure.
Column chromatography in (EtOAc/hexane 2:1) yielded 16 (2.9 g,
1
h and then was quenched with pyridine (1 mL) and concentrated
89%) as amorphous white solid: R
f
0.33 (EtOAc/hexane 1:2);
ꢀ
1
to a yellow oil under vacuum. The oil was chromatographed on
silica gel in (EtOAc/hexane 1:3) to yield 14 as a white waxy solid
[a
]
D
ꢁ14.8 (c 1.3, CHCl
3
); H NMR (500 MHz, CDCl 8.19e8.09
3
) d
(m, 1H, AreH), 7.87e7.80 (m, 2H, AreH), 7.67 (d, J¼6.8 Hz, 2H,
AreH), 7.60e7.49 (m, 2H, AreH), 7.49e7.34 (m, 6H, AreH), 7.30 (t,
J¼7.8 Hz, 2H, AreH), 7.19e6.93 (m, 5H, AreH), 5.60 (s, 1H), 5.39 (s,
1H), 4.94 (d, J¼7.1 Hz, 1H), 4.74 (d, J¼12.0 Hz, 1H), 4.63 (d,
J¼12.1 Hz, 1H), 4.58 (d, J¼7.6 Hz, 1H), 4.40 (dd, J¼10.6, 4.9 Hz, 1H),
4.28e4.14 (m, 2H), 3.92 (t, J¼9.4 Hz, 1H), 3.86 (td, J¼10.2, 9.8,
7.6 Hz, 2H), 3.83e3.79 (m, 1H), 3.80e3.71 (m, 3H), 3.63 (s, 3H),
3.57 (td, J¼9.7, 4.8 Hz, 1H), 3.44 (td, J¼9.8, 5.0 Hz, 1H), 3.40e3.33
(m, 1H), 3.20 (q, J¼7.3 Hz, 1H), 2.10e1.91 (m, 2H), 1.50e1.28 (m,
(
[
3.5 g, 94%) after concentration: R
a
f
0.3 (EtOAc/hexane 1:3);
ꢀ
1
]
D
ꢁ65.3 (c 1.4, CHCl
3
); H NMR (700 MHz, CDCl 8.02 (d,
3
) d
J¼7.7 Hz, 2H, AreH), 7.75 (d, J¼7.8 Hz, 2H, AreH), 7.64e7.58 (m,
4
H, AreH), 7.57e7.34 (m, 11H, AreH), 7.29 (dd, J¼15.8, 8.0 Hz, 2H,
AreH), 7.21 (t, J¼7.7 Hz, 2H, AreH), 7.11 (ddt, J¼21.5, 14.7, 7.1 Hz,
7
5
4
H, AreH), 5.67 (s, 1H), 5.40 (s, 1H), 5.38 (dd, J¼9.5, 4.0 Hz, 1H),
.33 (t, J¼7.3 Hz, 1H), 5.06 (d, J¼6.8 Hz, 1H), 4.75 (d, J¼12.1 Hz, 1H),
.66 (d, J¼12.1 Hz, 1H), 4.56 (t, J¼9.5 Hz, 1H), 4.36 (ddd, J¼15.1,
13
1
3
3
0.4, 5.0 Hz, 2H), 4.17 (td, J¼10.0, 5.0 Hz, 1H), 3.99 (t, J¼9.3 Hz, 1H),
3 3
4H), 1.12 (m, 2H); C NMR (126 MHz, CDCl ) d 174.0 (COCH ),
.94 (t, J¼9.6 Hz, 1H), 3.85 (t, J¼10.3 Hz, 2H), 3.81e3.76 (m, 2H),
164.7 (C]O), 164.5 (C]O), 137.9, 137.3, 137.2, 132.9, 132.7, 130.0,
129.9, 129.8, 129.7, 129.6, 129.2, 128.9, 128.4, 128.3, 128.2, 128.1,
128.0, 127.8, 127.4, 126.2, 126.0, 101.6, 101.5, 101.0, 100.7, 80.9, 79.4,
13
.59 (td, J¼9.8, 4.9 Hz, 1H); C NMR (176 MHz, CDCl
3
) d 164.9 (C]
O), 164.8 (C]O), 164.4 (C]O), 137.8, 137.3, 137.0, 133.8, 133.2,
32.9, 129.9, 129.7, 129.6, 129.3, 129.2, 129.1, 129.0, 128.8, 128.6,
28.5, 128.4, 128.3, 128.2, 128.11, 127.9, 127.5, 126.12, 126.0, 101.5,
01.1, 101.0, 90.4, 80.9, 79.0, 78.2, 75.3, 73.7, 73.5, 72.4, 68.8, 68.6,
1
1
1
78.4, 78.1, 73.8, 73.6, 73.6, 69.7, 68.8, 68.7, 66.5, 66.1, 51.4, 33.7,
þ
29.0, 25.3, 24.4. HRMS (ESI) calcd (MþNa)
54 56
C H O15Na: 967.3517.
Found: 967.3513.

H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
105
0
0
0
29.0, 25.3, 24.3. HRMS (ESI) calcd (MþNa)þ
4
b
.18. 5-Methoxycarbonylpentyl 2 -O-benzoyl-4 ,6 -O-benzylidene-
C
94
H
92
O27Na:
-D
-glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-benzylidene-
b
-D-
1675.5718. Found: 1675.5694.
glucopyranoside (17)
000 000 000
.20. 5-Methoxycarbonylpentyl 2 -O-benzoyl-4 ,6 -O-
4
00 00 00
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
To a solution of 16 (2.5 g, 2.6 mmol) in THF/CH
3
OH (1:1) (60 mL)
benzylidene-
benzylidene-
benzylidene-
benzylidene-
b-
b-
b-
b-
D
D
D
D
0
0
0
was added Pd/C (125 mg, 5% w/w). The reaction mixture was stirred
for 3 h under hydrogen atmosphere before it was filtered,
concentrated under reduced pressure to a colorless syrup. Column
chromatography of the crude product in (EtOAc/hexane 1:2) gave
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
-glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-
-glucopyranoside (19)
1
7 (2 g, 87%) as amorphous white solid: R
f
0.29 (EtOAc/hexane 1:2);
3
To a solution of 18 (1 g, 0.6 mmol) in THF/CH OH (1:1) (60 mL)
ꢀ
ꢀ
1
[
a
]
D
ꢁ9.06 (c 1.0, CHCl
3
); mp 81.0e83 C; H NMR (700 MHz,
7.82 (dd, J¼8.2, 1.4 Hz, 2H, AreH), 7.76e7.71 (m, 2H, AreH),
was added Pd/C (50 mg, 5% w/w). The reaction mixture was stirred
for 3 h under hydrogen atmosphere before it was filtered,
concentrated under reduced pressure to a colorless syrup. Column
chromatography of the crude product in (EtOAc/hexane 1:2) gave
CDCl
3
)
d
7
.57e7.49 (m, 4H, AreH), 7.46e7.33 (m, 10H, AreH), 7.30 (dd, J¼8.3,
.3 Hz, 2H, AreH), 5.57 (s, 1H), 5.38 (s, 1H), 5.26 (dd, J¼8.6, 7.5 Hz,
H), 5.13 (dd, J¼8.3, 7.1 Hz, 1H), 4.95 (d, J¼7.2 Hz, 1H), 4.57 (d,
J¼7.6 Hz, 1H), 4.38 (dd, J¼10.5, 4.9 Hz, 1H), 4.24e4.14 (m, 2H), 3.87
dd, J¼9.2, 8.2 Hz, 1H), 3.83 (td, J¼10.3, 9.8, 5.4 Hz, 2H), 3.79 (dt,
J¼9.7, 6.0 Hz, 1H), 3.71 (t, J¼10.3 Hz, 1H), 3.70e3.66 (m, 1H), 3.61 (s,
7
1
19 (690 mg, 73%) as amorphous white solid: R
f
0.30 (EtOAc/hexane
ꢀ
1
1:2); [
a
]
D
þ12.5 (c 2.4, CHCl
3
); H NMR (700 MHz, CDCl 7.95
3
) d
(
(dd, J¼8.3, 1.4 Hz, 2H, AreH), 7.85 (dd, J¼8.3, 1.4 Hz, 2H, AreH), 7.79
(dd, J¼8.3, 1.4 Hz, 2H, AreH), 7.66 (dd, J¼8.3, 1.4 Hz, 2H, AreH),
7.58e7.50 (m, 8H, AreH), 7.47 (dd, J¼7.7, 1.9 Hz, 2H, AreH),
7.45e7.31 (m, 16H, AreH), 7.30e7.23 (m, 5H, AreH), 7.22e7.17 (m,
1H, AreH), 5.55 (s, 1H), 5.44 (s, 1H), 5.19 (dd, J¼8.5, 7.4 Hz, 1H), 5.16
(t, J¼5.0 Hz, 1H), 5.08 (d, J¼7.4 Hz, 1H), 4.98 (d, J¼5.1 Hz, 1H), 4.95
(dd, J¼8.8, 7.8 Hz, 1H), 4.86e4.80 (m, 4H), 4.47 (d, J¼7.8 Hz, 1H),
4.34 (dd, J¼10.5, 4.8 Hz, 1H), 4.21 (dd, J¼10.5, 5.0 Hz, 1H), 4.16e4.09
(m, 3H), 4.07 (dd, J¼8.4, 4.9 Hz, 1H), 4.02e3.97 (m, 2H), 3.97e3.92
(m, 1H), 3.78 (dt, J¼9.9, 6.1 Hz, 1H), 3.75 (t, J¼10.2 Hz, 1H),
3.73e3.67 (m, 2H), 3.63 (s, 3H), 3.59 (td, J¼9.9, 4.2 Hz, 1H), 3.53 (t,
J¼10.1 Hz, 1H), 3.50e3.44 (m, 4H), 3.41 (tt, J¼9.9, 2.8 Hz, 2H), 3.35
3
H), 3.56 (td, J¼9.8, 4.9 Hz, 1H), 3.40 (td, J¼9.8, 5.0 Hz, 1H), 3.35
(
(
ddd, J¼9.7, 7.2, 5.8 Hz, 1H), 2.03 (ddd, J¼15.5, 8.8, 6.7 Hz, 1H), 1.96
13
ddd, J¼15.6, 8.6, 6.6 Hz, 1H), 1.47e1.33 (m, 4H), 1.11 (m, 2H);
173.9 (COCH ), 165.5 (C]O), 164.5 (C]O),
37.2, 136.9, 133.0, 132.9, 129.8, 129.6, 129.5, 129.3, 129.2, 129.1,
28.3, 128.2, 128.1, 126.3, 126.1, 101.7, 101.5, 101.4, 100.3, 80.5, 79.3,
C
NMR (126 MHz, CDCl
3
)
d
3
1
1
7
2
8.0, 75.3, 73.6, 72.6, 69.6, 68.76, 68.6, 66.4, 66.1, 51.4, 33.6, 28.9,
5.2, 24.4. HRMS (ESI) calcd (MþNa)þ
C
H
50
O15Na: 877.3042
47
Found: 877.3026.
(
ddd, J¼9.7, 7.2, 5.8 Hz,1H), 2.10e2.01 (m,1H),1.98 (ddd, J¼15.7, 8.6,
0
00
000
000 000
13
4.19. 5-Methoxycarbonylpentyl 2 -O-benzoyl-3 -O-benzyl-4 ,6 -
6.6 Hz, 1H), 1.48e1.34 (m, 4H), 1.20e1.06 (m, 2H); C NMR
(176 MHz, CDCl 173.9 (COCH ), 165.8 (C]O), 164.6 (C]O), 164.5
0
0
00 00
O-benzylidene-
b
-
D
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
3
)
d
3
0
0
0
benzylidene-
benzylidene-
benzylidene-
b
b
b
-
-
-
D-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
D-glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-
D-glucopyranoside (18)
(2C]O), 137.3, 137.2, 137.1, 137.0, 133.6, 133.3, 133.1, 133.0, 129.9,
129.8, 129.7, 129.6, 129.5, 129.4, 129.3, 129.24, 129.2, 129.1, 129.0,
128.9, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 128.1, 128.0, 126.4,
126.3, 126.2, 126.0, 101.8, 101.8, 101.5, 101.2, 100.7, 98.7, 98.6, 97.0,
To a solution of donor 15 (2 g, 2.3 mmol) and acceptor 17 (1.7 g,
mmol) in dry DCM (30 mL) was added crushed 4 Å molecular
sieves (3 g) and the mixture was stirred for 30 min at rt. NIS
80.8, 78.9, 78.1, 77.5, 76.8, 76.8, 75.4, 74.8, 74.3, 74.0, 73.6, 72.6, 72.5,
2
69.6, 68.7, 68.6, 66.4, 66.0, 65.6, 65.5, 51.4, 33.7, 29.0, 25.3, 24.3.
þ
HRMS (ESI) calcd (MþNa)
C
87
86
H O
27Na: 1585.5249. Found:
(
620 mg, 2.76 mmol) and AgOTf (26 mg, 0.1 mmol) were added to
1585.5243.
ꢀ
the mixture after it was cooled to ꢁ10 C and was stirred for
00000 00000 00000
4.21. 5-Methoxycarbonylpentyl 2 -O-benzoyl-4 ,6 -O-
additional 2 h at the same temperature. The reaction mixture was
0000 0000 0000
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
neutralized with Et
3
N (0.5 mL), filtered and concentrated to a
benzylidene-
benzylidene-
benzylidene-
benzylidene-
benzylidene-
benzylidene-
b-
b-
b-
b-
b-
b-
D
D
D
D
D
D
000 000 000
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
colorless syrup under reduced pressure. Column chromatography
in (EtOAc/hexane 1:2) yielded 18 (3 g, 91%) as amorphous white
00 00 00
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
ꢀ
0
0
0
solid: R
8.0e100.0 C; H NMR (700 MHz, CDCl
AreH), 7.79e7.75 (m, 2H, AreH), 7.66e7.61 (m, 2H, AreH),
.57e7.55 (m, 2H, AreH), 7.55e7.50 (m, 4H, AreH), 7.48e7.45 (m,
H, AreH), 7.44e7.22 (m, 23H, AreH), 7.19 (dd, J¼8.5, 6.5 Hz, 1H,
AreH), 7.14e7.10 (m, 3H, AreH), 7.07 (t, J¼7.6 Hz, 2H, AreH), 5.56 (s,
f
0.33 (EtOAc/hexane 1:2); [
a
]
D
þ8.4 (c 3.0, CHCl
3
); mp
7.88e7.81 (m, 4H,
-glucopyranosyl-(1/3)-2 -O-benzoyl-4 ,6 -O-
-glucopyranosyl-(1/3)-2-O-benzoyl-4,6-O-
-glucopyranoside (20)
ꢀ
1
9
3
)
d
7
2
To a solution of donor 15 (500 mg, 0.54 mmol) and acceptor 19
(700 mg, 0.45 mmol) in dry DCM (20 mL) was added crushed 4 Å
molecular sieves (1 g) and the mixture was stirred for 30 min at rt.
NIS (146 mg, 0.65 mmol) and AgOTf (26 mg, 0.1 mmol) were added
1
H), 5.44 (s, 1H), 5.31 (t, J¼7.9 Hz, 1H), 5.13 (t, J¼5.0 Hz, 1H), 5.01 (d,
J¼7.5 Hz, 1H), 4.95 (d, J¼5.5 Hz, 2H), 4.84e4.75 (m, 5H), 4.65 (d,
J¼12.1 Hz, 1H), 4.47 (d, J¼7.8 Hz, 1H), 4.35 (dd, J¼10.5, 4.7 Hz, 1H),
ꢀ
to the mixture after it was cooled to ꢁ10 C and was stirred for
4
4
.21 (dd, J¼10.4, 5.0 Hz, 1H), 4.17e4.07 (m, 3H), 4.03 (dd, J¼8.3,
.9 Hz,1H), 3.99 (t, J¼9.0 Hz,1H), 3.93 (dd, J¼8.5, 5.6 Hz,1H), 3.87 (t,
additional 4 h at the same temperature. The reaction mixture was
3
neutralized with Et N (0.2 mL), filtered and concentrated to a
colorless syrup under reduced pressure. Column chromatography
J¼9.3 Hz,1H), 3.85e3.67 (m, 5H), 3.63 (s, 3H), 3.58 (td, J¼9.8, 4.4 Hz,
1
3
2
H), 3.53 (t, J¼10.0 Hz, 1H), 3.51e3.43 (m, 4H), 3.43e3.38 (m, 2H),
in (EtOAc/hexane 1:2) yielded 20 (925 mg, 87%) as amorphous
ꢀ
.37e3.32 (m, 1H), 2.11e1.89 (m, 2H), 1.48e1.34 (m, 4H), 1.13 (m,
white solid: R
H NMR (700 MHz, CDCl
f
0.38 (EtOAc/hexane 1:2); [
a
]
D
þ18.0 (c 1.4, CHCl
3
);
1
3
1
H); C NMR (176 MHz, CDCl
3
)
d
173.9 (COCH
3
), 165.0 (C]O), 164.6
3
)
d
7.91e7.88 (m, 12H, AreH), 7.88e7.84
(
1
1
1
9
7
C]O), 164.5 (C]O), 164.4 (C]O), 137.9, 137.3, 137.2, 137.1, 133.4,
33.2, 133.0, 132.9, 129.8, 129.7, 129.6, 129.3, 129.1, 129.0, 128.9,
28.8, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 128.1, 128.03, 127.9,
27.8, 127.4, 126.4, 126.3, 126.1, 126.0, 101.8, 101.5, 101.2, 101.1, 100.7,
8.9, 98.6, 96.9, 81.2, 78.9, 78.3, 78.2, 77.5, 76.7 75.3, 74.1, 74.0, 73.7,
3.6, 73.4, 72.5, 69.6, 68.7, 68.6, 66.4, 66.0, 65.6, 65.4, 51.3, 33.6,
(m, 12H, AreH), 7.83e7.77 (m, 6H, AreH), 7.67e7.64 (m, 2H, AreH),
7.63e7.58 (m, 2H, AreH), 7.53 (t, J¼7.4 Hz, 2H, AreH), 7.51e7.21 (m,
43H, AreH), 7.21e7.17 (m, 1H, AreH), 7.17e7.12 (m, 3H, AreH), 7.09
(t, J¼7.3 Hz, 2H, AreH), 5.55 (s, 1H), 5.47 (s, 1H), 5.35 (t, J¼7.9 Hz,
1H), 5.19 (t, J¼4.9 Hz, 1H), 5.08 (d, J¼7.5 Hz, 1H), 5.00 (d, J¼5.1 Hz,
1H), 4.96 (t, J¼8.3 Hz, 1H), 4.92e4.85 (m, 7H), 4.83e4.77 (m, 4H),

106
H.R.H. Elsaidi et al. / Carbohydrate Research 408 (2015) 96e106
4
4
.68 (d, J¼12.1 Hz, 1H), 4.48 (d, J¼7.8 Hz, 1H), 4.35 (dd, J¼10.5,
.9 Hz, 1H), 4.25 (dd, J¼10.4, 4.9 Hz, 1H), 4.21e4.10 (m, 6H), 4.08
3. Bromuro C, Romano M, Chiani P, Berti F, Tontini M, Proietti D, et al. Vaccine
2010;28:2615e23.
4. Brown GD, Herre J, Williams DL, Willment JA, Marshall AS, Gordon S. J Exp Med
(
dd, J¼8.3, 4.7 Hz, 1H), 4.06e4.01 (m, 2H), 3.98 (dd, J¼8.3, 5.4 Hz,
2003;197:1119e24.
1
3
3
H), 3.96e3.93 (m, 1H), 3.90 (t, J¼9.3 Hz, 1H), 3.85 (t, J¼8.7 Hz, 1H),
.79 (dt, J¼9.8, 6.1 Hz, 1H), 3.74 (td, J¼10.2, 7.0 Hz, 2H), 3.64 (s, 3H),
.62e3.42 (m, 11H), 3.36 (ddd, J¼15.1, 11.8, 7.2 Hz, 3H), 2.10e1.93
5. Brown GD. Nat Rev Immunol 2006;6:33e43.
6
7
8
9
. Palma AS, Feizi T, Zhang Y, Stoll MS, Lawson AM, Díaz-Rodríguez E, et al. J Biol
Chem 2006;281:5771e9.
. Adams EL, Rice PJ, Graves B, Ensley HE, Yu H, Brown GD, et al. J Pharmacol Exp
Ther 2008;325:115e23.
. Tanaka H, Kawai T, Adachi Y, Ohno N, Takahashi T. Chem Commun 2010;46:
13
(
m, 2H), 1.51e1.37 (m, 4H), 1.20e1.08 (m, 2H); C NMR (176 MHz,
CDCl
64.6 (C]O), 164.5 (C]O), 138.0, 137.5, 137.4, 137.3, 137.2, 137.1,
33.8, 133.7, 133.6, 133.5, 133.4, 133.3, 130.0, 129.9, 129.8, 129.7,
29.6, 129.5, 129.4, 129.3, 129.2, 129.18, 129.17, 129.13, 129.08,
29.02, 128.9, 128.8, 128.7, 128.6, 128.5, 128.4, 128.3, 128.2, 128.14,
28.10, 127.9, 127.8, 127.4, 126.4, 126.3, 126.2, 126.1, 126.0, 101.9,
01.4, 101.30, 101.2, 101.1, 100.7, 98.7, 98.6, 97.1, 97.1, 96.9, 81.2, 78.9,
3 3
) d 173.9 (COCH ), 165.0 (C]O), 164.8 (C]O), 164.6 (2C]O),
8249e51.
1
1
1
1
1
1
. Sylla B, Gu eꢀ gan JP, Wieruszeski JM, Nugier-Chauvin C, Legentil L, Daniellou R,
et al. Carbohydr Res 2011;346:1490e4.
1
1
0. Tanaka H, Kawai T, Adachi Y, Hanashima S, Yamaguchi Y, Ohno N, et al. Bioorg
Med Chem 2012;20:3898e914.
1. Hanashima S, Ikeda A, Tanaka H, Adachi Y, Ohno N, Takahashi T, et al. Glycoconj
J 2014;31:199e207.
12. van Kooyk Y, Rabinovich GA. Nat Immunol 2008;9:593e601.
13. Unger WW, van Kooyk Y. Curr Opin Immunol 2011;23:131e7.
14. van Kooyk Y, Unger WW, Fehres CM, Kalay H, García-Vallejo JJ. Mol Immunol
2013;55:143e5.
7
7
6
8.4, 78.1, 77.9, 77.6, 76.6, 75.4, 74.6, 74.3, 74.1, 74.0, 73.7, 73.4, 73.4,
3.3, 72.9, 72.4, 69.6, 68.9, 68.8, 68.7, 68.6, 68.5, 66.4, 66.1, 65.6,
5.5, 65.4, 51.4, 33.6, 29.5, 25.3, 24.3. HRMS (ESI) calcd (MþNa)
þ
15. Fehres CM, Unger WW, Garcia-Vallejo JJ, van Kooyk Y. Front Immunol 2014 Apr
;5:149. http://dx.doi.org/10.3389/fimmu.2014.00149.
6. Lipinski T, Fitieh A, St. Pierre J, Ostergaard HL, Bundle DR, Touret N. J Immunol
013;190:4116e28.
17. Lipinski T, Wu X, Sadowska J, Kreiter E, Yasui Y, Cheriaparambil S, et al. Vaccine
012;30:6263e9.
8
C
134 128
H O39Na: 2383.7925. Found: 2383.7908.
1
2
Acknowledgments
2
1
1
8. Lemieux RU, Bundle DR, Baker DA. J Am Chem Soc 1975;97:4076e83.
This research was support by a grant to D. R. Bundle from the
Alberta Glycomics Centre and the Natural Science and Engineering
Research Council of Canada.
9. (a) Solladi eꢀ G, Ziani-Cherif C. J Org Chem 1993;58:2181e5;
(b) El Fangour S, Guy A, Despres V, Vidal J-P, Rossi J-C, Durand T. J Org Chem
2004;69:2498e503.
20. Kamath VP, Diedrich P, Hindsgaul O. Glycoconj J 1996;13:315e9.
2
1. Yu H, Williams DL, Ensley HE. Tetrahedron Lett 2005;46:3417e21.
Supplementary data
22. Jamois F, Ferrieres V, Guegan JP, Yvin JC, Plusquellec D, Vetvicka V. Glycobiology
005;15:393e407.
2
2
3. Adamoa R, Tontinia M, Brogionia G, Romanoa MR, Costantinia G, Danielia E,
et al. J Carbohydr Chem 2011;30:249e80.
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.carres.2015.03.
24. Zeng Y, Ning J, Kong F. Carbohydr Res 2003;338:307e11.
25. Mo KF, Li H, Mague JT, Ensley HE. Carbohydr Res 2009;344:439e47.
26. Weishaupt MW, Matthies S, Seeberger PH. Chemistry 2013;19:12497e503.
27. Ning J, Kong F, Lin B, Lei H. J Agric Food Chem 2003;51:987e91.
28. Collins PM. Tetrahedron 1965;21:1809e15.
0
07. These data include MOL files and InChiKeys of the most
important compounds described in this article.
References
29. Al-Mughaid H, Grindley TB. J Org Chem 2006;71:1390e8.
30. (a) Bock K, Pedersen C. J Chem Soc Perkin Trans 1974;2:293e9;
(
b) Bock K, Lundt I, Pedersen C. Tetrahedron Lett 1973:1037e40.
1
2
. Torosantucci A, Bromuro C, Chiani P, De Bernardis F, Berti F, Galli C, et al. J Exp
Med 2005;202:597e606.
. Torosantucci A, Chiani P, Bromuro C, De Bernardis F, Palma AS, Liu Y, et al. PLoS
One 2009;4:e5392.
3
3
3
1. Nitz M, Bundle DR. J Org Chem 2001;66:8411e23.
2. Elsaidi HRH, Barreda DR, Cairo CW, Lowary TL. ChemBioChem 2013;14:2153e9.
3. Olsson JDM, Oscarson S. Tetrahedron Asymmetry 2009;20:879e86.