Synthesis of 6-thio pseudo glycolipids and their orientation on a gold slide studied by IRRAS

Article abstract of DOI:10.1016/j.carres.2010.09.035

We have synthesized four 6-thio pseudo glycolipid analogues and assessed how two of them self-assembled on a gold surface. These structures were designed as candidate tethers molecules to anchor bilayer lipid membranes on gold. 6-Deoxy-6-thiogalactose was chosen to anchor the macromolecule to the gold and define an aqueous zone at the gold surface. A long alkane chain (C-12 or C-18) linked to the anomeric position of the sugar residue was chosen to anchor a bilayer lipid membrane. The linkage between the carbohydrate and the hydrophobic chains is either a glycosidic bond or a 1,4-disubstituted triazole formed by copper(I)-catalysed alkyne-azide cycloaddition (CuAAC) of the propargyl glycoside with azido-dodecane and azido-octadecane. We are expecting that the hydrocarbon chains will orient themselves perpendicular to the gold surface and be incorporated into the first leaflet of the bilayer membrane. We have studied self assembled monolayers of the C-12 aglycone analogues on gold using infrared reflection absorption spectroscopy (IRRAS). We compared the results given by the IRRAS experiments to the IR spectra recorded by attenuated total reflection (ATR) spectroscopy on films of the randomly oriented analogues. Our results demonstrate that the C-12 analogues did bind to gold and did orient themselves perpendicular to the gold slide.

Full text of DOI:10.1016/j.carres.2010.09.035

Carbohydrate Research 345 (2010) 2723–2730
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Note
Synthesis of 6-thio pseudo glycolipids and their orientation on a gold slide
studied by IRRAS
⇑
Mickael Guillemineau, Serena Singh, Michael Grossutti, France-Isabelle Auzanneau
Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 18 August 2010
Received in revised form 28 September 2010
Accepted 30 September 2010
Available online 23 October 2010
We have synthesized four 6-thio pseudo glycolipid analogues and assessed how two of them self-assem-
bled on a gold surface. These structures were designed as candidate tethers molecules to anchor bilayer
lipid membranes on gold. 6-Deoxy-6-thiogalactose was chosen to anchor the macromolecule to the gold
and define an aqueous zone at the gold surface. A long alkane chain (C-12 or C-18) linked to the anomeric
position of the sugar residue was chosen to anchor a bilayer lipid membrane. The linkage between the
carbohydrate and the hydrophobic chains is either a glycosidic bond or a 1,4-disubstituted triazole
formed by copper(I)-catalysed alkyne-azide cycloaddition (CuAAC) of the propargyl glycoside with
azido-dodecane and azido-octadecane. We are expecting that the hydrocarbon chains will orient them-
selves perpendicular to the gold surface and be incorporated into the first leaflet of the bilayer mem-
brane. We have studied self assembled monolayers of the C-12 aglycone analogues on gold using
infrared reflection absorption spectroscopy (IRRAS). We compared the results given by the IRRAS exper-
iments to the IR spectra recorded by attenuated total reflection (ATR) spectroscopy on films of the ran-
domly oriented analogues. Our results demonstrate that the C-12 analogues did bind to gold and did
orient themselves perpendicular to the gold slide.
Keywords:
6-Thio pseudo glycolipid analogues
Carbohydrate-based tether
Bilayer lipid membrane
Ó 2010 Elsevier Ltd. All rights reserved.
The complexity of biological membranes makes their direct
study very challenging and the design and development of artificial
model membranes constitutes an area of intensive research.1–3
Amongst these artificial model membranes, artificial bilayer lipid
membranes (BLMs) supported on glass, quartz, silicon or gold are
of considerable interest since they can be characterized easily
using various analytical techniques: SPR, EIS, AFM etc.4–14 These
artificial bilayer membranes are either freely supported on the so-
lid surface4,5 or tethered to the surface.6–14 While the freely sup-
ported membranes maintain better fluidity than the tethered
BLMs, they are often unstable and present structural defects.1–5
In contrast, tethered artificial bilayer membranes exhibit good sta-
bility and thus many such models have been developed in the past
two decades.1–3,6–14 Whether tethered or freely supported, the
supported BLMs designed for the study of transmembrane proteins
and events must be separated from the solid support by an hydro-
philic layer1–3 that allows the incorporation of the transmembrane
proteins9,11,13,14 or the transport of ions and molecules.15 For this
purpose many tethers have been developed and they are usually
made up of three domains: (1) a lipid chain that inserts itself in
the first leaflet of the BLM; (2) an hydrophilic spacer molecule such
as an amphiphilic copolymer,6 a polyethyleneglycol chain7–10 or a
peptide chain11–14 that provides the necessary hydrophilic region
between the BLM and the solid support and (3) an anchoring func-
tional group such as a disulfide6–8,10–12,16 or thiol8,12–14,17 for gold
support or a silane for glass immobilization.9 In this study, we
are proposing the development of a new type of tether molecules
in which the hydrophilic spacer molecule is based on a thiocarbo-
hydrate that is self adsorbed on gold. Self-assembled monolayers
(SAM) of 1-b-D-thioglucose on gold have been described by
Revell18 and used by Quirk19 to study the enzymatic digestion of
freely supported cellulose fibres by atomic force microscopy.
However, it is only very recently20 that SAMs of 1-b-
D-thioglucose
on gold were studied at the molecular level by electrochemical
scanning tunnelling microscopy (EC-STM) and polarization modu-
lation infrared reflection adsorption spectroscopy (PM-IRRAS).
These studies20 demonstrated that, upon self-assembly on gold,
1-b-
thus providing an organised hydrophilic layer on the gold slide.
Thus, one may suggest that an alkane chain at O-4 of 1-b- -thioglu-
D-thioglucose oriented itself perpendicular to the gold surface,
D
cose would extend perpendicular to the gold surface and be able to
insert itself in the first leaflet of a BLM while the glucose moiety
provides a hydrophilic zone between the solid substrate and the
BLM. However, it has been shown that 1-b-
on a solid silver electrode had the potential to anomerize to a mix-
ture of
and b anomers.21 Thus, since the configuration of the ano-
D-thioglucose adsorbed
a
meric thiol linked to gold will determine the orientation of the
sugar and, therefore, the orientation of the O-4 linked lipid chains,
⇑
Corresponding author. Tel.: +1 519 824 4120x53809; fax: +1 519 766 1499.
E-mail address: fauzanne@uoguelph.ca (F.-I. Auzanneau).
0008-6215/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2010.09.035

2724
M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
the ability of 1-thioglucose to anomerize precludes its use as such
a carbohydrate template. We envisioned that the introduction of a
thiol at C-4 or C-6 of a sugar unit together with that of a long al-
kane chain at the anomeric position would give novel interesting
tether molecules that would not be able to undergo anomerization
on the gold surface. We postulated that a 6-thio hexose would be
able to self-assemble perpendicularly to the gold surface and that
a lipid chain positioned equatorial (i.e., b) at the anomeric position
would extend perpendicular to the gold surface and thus be able to
anchor a BLM as represented schematically on Figure 1. Based on
its ease of synthesis, we chose to use 6-deoxy-6-thiogalactose to
anchor the macromolecule to the gold surface and define the
aqueous zone between the gold surface and the bilayer while
C-12 or C-18 alkane chains linked at the anomeric position were
chosen with the expectation that they would be able to insert
themselves in the first leaflet of a BLM (Fig. 1). The linkage between
the carbohydrate and the hydrophobic chains is either a b glyco-
sidic bond as in compounds 1 and 2, or a 1,4-disubstituted triazole
formed by copper(I)-catalysed alkyne-azide cycloaddition (CuAAC)
as in analogues 3 and 4.22,23 Thus, we report here the synthesis of
four pseudo glycolipid analogues 1–4 as a first generation of carbo-
hydrate-based tether molecules to anchor bilayer lipid membranes
to gold. The construction and study of tethered BLMs using these
novel 6-thio pseudo glycolipids are beyond the scope of this paper.
However, in order to demonstrate that our analogues did bind and
orient themselves on a gold slide, self-assembled monolayers of 1
and 3 were studied by infrared reflection absorption spectroscopy
(IRRAS).24 Analogues 1 and 3 did indeed orient themselves on the
gold slide in such a way that the lipid chains extended perpendic-
ular to the gold surface and should therefore be able to insert
themselves in the first leaflet of a BLM as proposed on Figure 1.
SAc
O
O
O
O
O
5
a
SAc
O
R3O
R3O
R1
R3O
R2
6 R1, R2 = H, OH, R3 = H
7 R1 = H, R2 = Br, R3 = Ac
b
c
SAc
AcO
AcO
O
O
n
OAc
8 n = 11
9 n = 17
Scheme 1. Reagents and conditions: (a) TFA–AcOH–H2O (5:3:2), rt (95%); (b) (i)
Ac2O–pyridine, 50 °C, (ii) 33% HBr–AcOH, rt (50%); (c) dodecanol or octadodecanol,
Hg(CN)2, toluene, MS 4 Å, 40 °C (76%).
mediate polyol 6 as described previously by Elhalabi and Rice using
a mixture of acetic anhydride–acetic acid–sulfuric acid.26 However,
in our hands the desired peracetate was obtained in only 5% yield.
Thus, diisopropylidene 5 was treated with a mixture of TFA–AcOH–
H2O and the resulting polyol 6 was isolated and purified by column
chromatography (Scheme 1). Acetylation followed by treatment of
the peracetate intermediate with HBr in acetic acid gave the
known27 glycosyl bromide 7 which was, in turn, glycosidated with
either dodecanol or octadecanol under Helfrich conditions. To al-
low an efficient purification of the desired glycosides, the excess
alcohol was acetylated in situ by treating the reaction mixtures
with acetic anhydride–pyridine and the desired glycosides 8 and
9 were isolated in good yield upon column chromatography. Final-
ly, Zemplèn deacetylations gave the glycolipid analogues 1 and 2 in
excellent yields.
SH
HO
O
HO
O
n
OH
1 n = 11
2
n = 17
SH
HO
HO
N
N
O
O
N
n
OH
3 n = 11
CuI-catalysed azide-alkyne 1,3-dipolar cycloaddition or the so-
called ‘click’ chemistry is an attractive approach to efficiently couple
two entities28 and since its development22,23 it has been used to
make a large number of new compounds including glycoclusters,
glycodendrimers and glycopolymers.29–34 In this report, we applied
this method to link the propargyl glycoside 10 to the known azides
1135 and1236 (Scheme2). Thus, propargylglycoside10wasprepared
4
n = 17
The synthesis of compounds 1 and 2 was easily carried out in
four steps from the known25 6-deoxy-6-thioacetate diisopropylid-
ene galactose derivative 5 (Scheme 1). We first attempted to
remove the isopropylidene groups and in situ acetylate the inter-
OH
HO
HO
O
O
S
Hydrophilic zone
Bilayer membrane
Figure 1. Proposed model of a tethered bilayer lipid membrane using carbohydrate-based tether 1 as the anchoring molecule.

M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
2725
and, therefore,donotneedtobeseparated, columnchromatography
easily allowed separation of the thiol 4 and disulfide 15. It is impor-
tant to note that the C-18 aglycone analogues 2 and 4 were poorly
soluble in any given pure solvent other than DMSO. However, they
couldbe solubilizedinto a 9:1mixtureof CDCl3–CD3ODandthiscon-
stituted the best solvent to acquire NMR data without favouring the
oxidation of the thiol to the disulfide. We were able, in this solvent
mixture, to identify key NMR features that are characteristic to the
thiol and disulfide, respectively. Indeed, H-6a and H-6b in thiol 4
gave signals in the 1H NMR spectrum at 2.82 and 2.67 ppm, respec-
tively, while the same signals in disulfide 15 were found at a lower
field: 3.05 and 2.96 ppm, respectively. An even more obvious differ-
ence in chemical shift of C-6 in the thiol and disulfide was also found
in the 13C NMR spectra. Indeed, C-6 in thiol 4 gave a signal at
24.4 ppm while the same carbon in disulfide 15 gave a signal at
39.4 ppm. The NMR features identified in thiol 4 were also found
in analogues 1–3 confirming that these analogues did not contain
any disulfide.
7
a
SAc
O
AcO
AcO
O
OAc
10
11 n = 11
b
n
N3
12
n = 17
SAc
AcO
AcO
N
N
O
O
N
OAc
13
n
OH
n = 11
14 n = 17
N
HO
HO
HO
HO
O
17
O
N
N
N
Scheme 2. Reagents and conditions: (a) AgOTf, TMU, propargyl alcohol, CH2Cl2,
ꢁ40 °C to rt (56%); (b) 11 or 12, THF–water 11:3, Na ascorbate, CuSO4, 5H2O, rt (55%
for 13, 59% for 14).
S
S
N
from glycosyl bromide 7 through glycosidation with propargyl alco-
hol. We first attempted this glycosidation under Helfrich conditions
as described above for the synthesis of glycosides 8 and 9. However,
under these conditions the desired glycoside was obtained contam-
inated with the corresponding orthoester. Best results were ob-
tained when the reaction was carried out under AgOTf–TMU
activation and even though propargyl glycoside 10 was isolated in
a mediocre 56% yield it could be easily purified by column chroma-
tography. The preparation of the known35,36 azides 11 and 12 was
accomplished in two steps from the corresponding alcohols. Dodec-
anol and octadecanol were first converted into the corresponding io-
dide analogues (PPh3, imidazole, I2) which were, in turn, submitted
to nucleophilic displacement with sodium azide in DMF. The desired
azido-dodecane 11 and azido-octadecane 12 were obtained in 70%
and 78% yields, respectively, over the two steps. The cycloaddition
between propargyl glycoside 10 and the azido-alkane 11 and 12
was carried out in a mixture of THF and water using a slight excess
of azide (1.1 equiv). Copper(I) was generated in situ through the
reductionofthecopper(II)sulfatebysodiumascorbateandthe‘click’
adducts 13 and 14 were obtained in 55% and 59% yields, respectively.
These yields are comparable to that reported recently for the cyclo-
addition between peracetylated propargyl b-glucopyranoside and
11-azidoundecanoic acid.37 Attempts to further improve the yield
of these reactions by using copper(I) iodide in THF were unsuccess-
O
O
N
17
OH
15
Compounds 1 and 3 were self-assembled on polycrystalline gold
slides and studied using infrared reflection absorption spectroscopy
(IRRAS), an analytical technique which allows the recording of IR
data on gold-adsorbed monolayer films. For comparative purposes,
films of compounds 1 and 3 were deposited on a ZnSe internal reflec-
tion element and studied using attenuated total reflection (ATR)
spectroscopy, an analytical technique that allows the recording of
IR data for a film (ꢀ1
lm thick) of randomly oriented molecules.
Comparingthetwo sets of IR data gave us informationon theadsorp-
tion and orientation of the pseudo-glycolipids 1 and 3 on the gold
slide.24 Figures 2 and 3 show two regions of the ATR and IRRAS spec-
tra obtained for 1 and 3. Figure 2 shows the asymmetric
as(CH3), and symmetric s(CH2), s(CH3) stretching vibrations ob-
served in the ATR and IRRAS spectra of compounds 1 and 3. As can
be seen in the IRRAS spectra these bands [ as(CH3), as(CH2), s(CH3),
s(CH2)] are centred at 2964, 2926, 2877 and 2854 cmꢁ1, respec-
mas(CH2),
m
m
m
m
m
m
m
tively, and are in total agreement with those recorded in the ATR
spectra (centred at 2954, 2920, 2872 and 2852 cmꢁ1, respectively)
clearly indicating a successful adsorption of 1 and 3 on the gold slide.
In addition, when compared to the ATR spectra obtained for the ran-
domly oriented glycolipids 1 and 3 on ZnSe, the IRRAS spectra of the
SAM of 1 and 3 on gold show a clear decrease in band intensityfor the
ful. The structure of analogue 13 and 14 was confirmed by 1H and 13
C
NMR as well as HR-ESIMS. Indeed, the 1,4 disubstituted triazole ring
gave a typical singlet at 7.48 ppm and typical signals at ꢀ145 and
ꢀ125 ppm in the 1H and 13C NMR spectra, respectively. The large dif-
ference in chemical shift measured for the triazole carbon atoms
mas(CH2) relative to mas(CH3). This decrease in mas(CH2) intensity sug-
gests that the lipid chains in glycolipids 1 and 3 are extended and ori-
ented perpendicular to the surface of the gold slide.24 This
orientation of the lipid chains in 1 and 3 is ideal for their insertion
into the fist leaflet of a bilayer. Finally, the clear differences
observed in Figure 3 that shows the IRRAS and ATR spectra in the
ꢀ1500–1000 cmꢁ1 region also suggest orientation at the gold
surface.24
Thus as postulated the 6-thio galactose analogues 1 and 3 did
self-assemble perpendicularly to the gold surface allowing the lipid
chains positioned equatorial (i.e., b) at the anomeric position to
extend perpendicular to the gold surface for insertion into the first
leaflet of a BLM. Further studies are on going to assess the ability of
the hydrocarbon chains to tether an artificial bilayer membrane
[
D
(dC4 ꢁ dC5) = ꢀ20 ppm] was characteristic in both cases of the ex-
pected formation of the 1,4 regioisomers.38 Zemplèn deacetylation
of analogue 13 gave the desired pseudo glycolipid analogue 3 in
quantitative yield. Interestingly, Zemplèn deacetylation of analogue
14 under the same conditions than used to prepare the thiols 1–3
gave the thiol 4 contaminated with 10% of the corresponding disul-
fide 15. The deacetylation of analogue 14 was carried out on multiple
samples and it was observed that the amount of disulfide formation
varied from one deacetylation to the next. We also observed that dis-
solving the product of this reaction in DMSO to acquire NMR data fa-
voured the oxidation of thiol 4 to the disulfide 15. Even though both
thiols8,12–14,17 and disulfides6–8,10–16 can be immobilized on gold

2726
M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
Figure 2. ATR (top trace) and IRRAS (bottom trace, collected at a 70° incident angle)
spectra of (a) compound 1 and (b) compound 3 for the asymmetric as(CH2), as(CH3),
and symmetric s(CH2), s(CH3) stretching vibrations (a.u. denotes absorbance units).
m
m
Figure 3. ATR (top trace) and IRRAS (bottom trace, collected at a 80° incident angle)
spectra of (a) compound 1 and (b) compound 3 for the ꢀ1500–1000 cmꢁ1 region
(a.u. denotes absorbance units).
m
m
while the galactose residue provides the required hydrophilic
region between the first leaflet of the bilayer and the gold support.
However, when tethering BLMs to gold using analogues 1–4, it is
clear that one sugar residue will not provide a hydrophilic zone
thick enough to allow the insertion of transmembrane proteins
into the model membrane. Indeed, these first generation tether
candidates (1–4) were synthesized to test our hypothesis that if
the thiol was placed at C-6 and the lipid chain equatorial at the
anomeric position, the orientation of the lipid chain could allow
anchoring of a BLM. We are now preparing a second generation
of carbohydrate-based tether molecules using di- and tri- saccha-
rides as carbohydrate templates. The disaccharide-based pseudo
glycolipids will have a thiol at the 6-position of the non-reducing
13C CDCl3 d 77.0), CD3OD (internal standard, for 1H residual
CD2HOD d 3.30; for 13C CD3OD d 49.0) or DMSO-d6 (internal stan-
dard, for 1H residual CD2HSOCD3 d 2.49; for 13C DMSO-d6 d 39.0).
Chemical shifts (ppm) and coupling constants (J, Hz) were obtained
from a first-order analysis of one-dimensional spectra and assign-
ments of proton and carbon resonances were based on two dimen-
sional 1H–1H and 13C–1H correlation experiments. 1H NMR data are
reported using standard abbreviations: singlet (s), doublet (d), trip-
let (t), doublet of doublet (dd), triplet of doublet (td) and multiplet
(m). TLC was performed on aluminium plates precoated with Silica
Gel 60 (250 lm) containing a fluorescent indicator. The plates were
visualized under UV and charred with a 10% solution of H2SO4 in
EtOH. Compounds were purified by flash chromatography with Sil-
ica Gel 60 (230–400 mesh) unless otherwise stated. Solvents were
distilled and dried according to standard procedures39 and organic
solutions were dried over Na2SO4 and concentrated under reduced
pressure below 40 °C. Optical rotations were measured at 23 °C on
a Rudolph Research Autopol III polarimeter and reported as fol-
end sugar that will be b-linked to the 4-position of a D-glucoside
residue carrying a b-linked lipid chain at the anomeric position.
Based on the results presented herein, we expect that the use of
such disaccharides (6-thio lactose or cellobiose) will maximize an
extended orientation of the disaccharide perpendicular to the gold
surface and that the b-linked lipid chains will also extend perpen-
dicular to the gold surface for tethering of a BLM.
lows: [a] (c in grams per 100 mL, solvent). High resolution elec-
D
trospray ionization mass spectra (HRESI MS) were recorded by
the analytical services of the McMaster Regional Center for Mass
Spectrometry, Hamilton, Ontario.
1. Experimental
1.1. General methods
1.2. Dodecyl 6-thio-b-D-galactopyranoside (1)
1H NMR (600.13 or 400.13 MHz) and 13C NMR (150.9 or
100.6 MHz) spectra were recorded with Bruker Avances spectrom-
eters in CDCl3 (internal standard, for 1H residual CHCl3 d 7.24; for
Sodium (20 mg, 0.866 mmol, 4 equiv) was added to a solution of
peracetate 8 (115 mg, 0.217 mmol, 1 equiv) in anhyd MeOH

M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
2727
(8.5 mL), the reaction mixture was stirred at rt for 1 h and deionized
with Dowex 50 (H+) resin. The resin was filtered off, washed with
MeOH(25 mL)andthecombinedfiltrateandwashingswereconcen-
trated yielding pure glycolipid analogue 1 (74 mg, 94%) as a white
30.4, 30.1, 27.5, 23.7 (NCH2(CH2)10CH3), 25.2 (C-6), 14.5
(N(CH2)11CH3). HRESIMS calcd for C21H39O5N3SNa [M+Na]+:
468.2508, found: 498.2505.
amorphous powder. [a]
+8.0 (c 1.0, MeOH). 1H NMR (400 MHz,
D
1.5. 1-Octadecane-4-(6-thio-b-
[1,2,3]-triazole (4) and 1-octadecane-4-(6-thio-b-
D
-galactopyranosyloxymethyl)-
-galacto-
CD3OD): d 4.18 (d, 1H, J = 7.2 Hz, H-1), 3.91 (d, 1H, J = 2.1 Hz, H-4),
3.85 (m, 1H, OCHaHb(CH2)10CH3), 3.55 (m, 1H, OCHaHb(CH2)10CH3),
3.48–3.41 (m, 3H, H-2, H-3, H-5), 2.79 (dd, 1H, J = 7.3, 13.6 Hz,
H-6a), 2.66 (dd, 1H, J = 6.6, 13.6 Hz, H-6b), 1.62 (2H, m,
OCH2CH2(CH2)9CH3), 1.28 (m, 18H, OCH2CH2(CH2)9CH3), 0.89 (t,
3H, J = 6.6 Hz, O(CH2)11CH3). 13C NMR (100 MHz, CD3OD): d 105
(C-1), 78.0 (C-5), 75.0 (C-3), 72.4 (C-2), 71.0 (OCH2(CH2)10CH3),
70.3 (C-4), 33.1, 30.9, 30.8, 30.6, 30.5, 27.1, 23.7 (OCH2(CH2)10CH3),
25.2 (C-6), 14.5 (O(CH2)11CH3). HRESIMS calcd for C18H40NO5S
[M+NH4]+: 382.2627, found: 382.2637.
D
pyranosyloxymethyl)-[1,2,3]-triazole disulfide (15)
Sodium (7 mg, 0.304 mmol, 4 equiv) was added to a solution of
peracetate 14 (53 mg, 76 lmol, 1 equiv) in anhyd MeOH (7.6 mL)
and the reaction was left to proceed (1.5 h) and worked up as de-
scribed Section 1.2 for the preparation of compound 1. After evap-
oration of the solvent, the mixture (35 mg, 88%, 4/15 = 9:1
estimated by 1H NMR) of glycolipid analogue 4 and disulfide 15
was obtained as an amorphous powder. For analytical purpose,
these two products were separated by column chromatography
(MeOH–CH2Cl2, 8:92).
1.3. Octadecyl 6-thio-b-D-galactopyranoside (2)
Sodium (11.2 mg, 0.486 mmol, 2 equiv) was added to a solution
of peracetate 9 (150 mg, 0.243 mmol, 1 equiv) in anhyd MeOH
(2.5 mL) and the reaction was left to proceed (2 h) and worked up
as described Section 1.2 for the preparation of compound 1.
Glycolipid analogue 2 (80 mg, 73%) was obtained pure as a white
1.5.1. Analytical data for thiol 4
[a
]
D
ꢁ10.0 (c 1.0, 9:1.0 CHCl3–MeOH). 1H NMR (400 MHz, 9:1
CDCl3–CD3OD): d 7.57 (s, 1H, @CH), 4.92 (d, 1H, J = 12.2 Hz, OCHaHb),
4.67 (d, 1H, J = 12.2 Hz, OCHaHb), 4.30–4.22 (m, 3H, H-1,
NCH2(CH2)16CH3), 3.90 (d, 1H, J = 2.6 Hz, H-4), 3.56–3.44 (m, 2H,
H-2, H-3), 3.40 (t, 1H, J = 7.0 Hz, H-5), 2.82 (dd, 1H, J = 7.3, 13.8 Hz,
H-6a), 2.67 (dd, 1H, J = 6.4, 13.7 Hz, H-6b), 1.81 (t, 2H, J = 6.8 Hz,
NCH2CH2(CH2)15CH3), 1.28–1.10 (m, 30H, NCH2CH2(CH2)15CH3),
0.79 (t, 3H, J = 6.6 Hz, N(CH2)17CH3). 13C NMR (100 MHz, 9:1
CDCl3–CD3OD): d 144.0 (C@CH), 122.7 (C@CH), 102.6 (C-1), 76.6
(C-5), 73.4 (C-3), 71.1 (C-2), 68.6 (C-4), 62.1 (OCH2), 50.5
(NCH2(CH2)16CH3), 31.9, 30.2, 29.6, 29.5, 29.3, 28.9, 26.4, 22.6
(NCH2(CH2)16CH3), 24.4 (C-6), 14.0 (N(CH2)17CH3). HRESIMS calcd
for C27H51O5SN3Na [M+Na]+: 552.3447, found: 552.3461.
amorphous powder. [
a]
ꢁ9.5 (c 1.0, 9:1 CHCl3–MeOH). 1H NMR
D
(400 MHz, 9:1 CDCl3–CD3OD): d 4.14 (m, 1H, H-1), 3.91 (s, 1H,
H-4), 3.83 (m, 2H, OCHaHb(CH2)16CH3), 3.54–3.43 (m, 3H, H-2, H-3,
OCHaHb(CH2)16CH3), 3.39 (t, 1H, J = 7.0 Hz, H-5), 2.81 (m, 1H,
H-6a), 2.65 (dd, 1H, J = 6.7, 14.3 Hz, H-6b), 1.56 (m, 2H,
OCH2CH2(CH2)15CH3), 1.33–1.10 (m, 30H, OCH2CH2(CH2)15CH3),
0.80 (t, 3H, J = 6.4 Hz, O(CH2)17CH3). 1H NMR (400 MHz, DMSO-d6):
d 4.81 (d, 1H, J = 4.2 Hz, OH-2), 4.71, (d, 1H, J = 5.0 Hz, OH-3), 4.51
(d, 1H, J = 4.8 Hz, OH-4), 4.04 (d, 1H, J = 7.1 Hz, H-1), 3.74–3.65 (m,
2H, H-4, OCHaHb(CH2)16CH3), 3.40 (m, 1H, OCHaHb(CH2)16CH3),
3.34–3.29 (m, 1H, H-5), 3.27–3.19 (m, 2H, H-2, H-3), 2.67–2.54 (m,
2H, H-6a, H-6b), 2.18 (t, 1H, J = 8.9 Hz, SH), 1.50 (m, 2H,
OCH2CH2(CH2)15CH3), 1.33–1.18 (m, 30H, OCH2CH2(CH2)15CH3),
0.84 (t, 3H, J = 6.5 Hz, O(CH2)17CH3). 13C NMR (100 MHz, 9:1
CDCl3–CD3OD): d 103.0 (C-1), 76.4 (C-5), 73.4 (C-3), 71.3 (C-2),
70.2 (OCH2(CH2)16CH3), 68.7 (C-4), 31.8, 29.6, 29.5, 29.3, 29.2, 25.8,
24.5, 22.6 (OCH2(CH2)16CH3), 24.3 (C-6), 14.0 (O(CH2)17CH3). 13C
NMR (100 MHz, DMSO-d6): d 103.4 (C-1), 76.0 (C-5), 73.3 (C-3),
70.3 (C-2), 68.6 (OCH2(CH2)16CH3), 68.3 (C-4), 31.3, 29.3, 29.0, 28.9,
28.7, 25.5, 22.1 (OCH2(CH2)16CH3), 24.3 (C-6), 13.9 (O(CH2)17CH3).
1.5.2. Analytical data for disulfide 15
[a
]
D
ꢁ12.0 (c 0.3, 9:1 CHCl3–MeOH). 1H NMR (400 MHz, 9:1
CDCl3–CD3OD): d 7.59 (s, 2H, @CH), 4.94 (d, 2H, J = 12.3 Hz,
OCHaHb), 4.67 (d, 2H, J = 12.2 Hz, OCHaHb), 4.30 (d, 2H, J = 7.1 Hz,
H-1), 4.25 (t, 2H, J = 7.2 Hz, NCH2(CH2)16CH3), 3.87 (s, 2H, H-4),
3.67 (t, 2H, J = 6.7 Hz, H-5), 3.58–3.49 (m, 4H, H-2, H-3), 3.05 (dd,
2H, J = 7.5, 14.0 Hz, H-6a), 2.96 (dd, 2H, J = 5.8, 13.8 Hz, H-6b),
1.81 (t, 4H, J = 6.8 Hz, NCH2CH2(CH2)15CH3), 1.30–1.13 (m, 60H,
NCH2CH2(CH2)15CH3), 0.81 (t, 6H, J = 6.6 Hz, N(CH2)17CH3). 13C
NMR (100 MHz, 9:1 CDCl3–CD3OD): d 143.9 (C@CH), 122.8 (C@CH),
102.5 (C-1), 73.5 (C-5), 73.3 (C-3), 71.0 (C-2), 69.1 (C-4), 62.0
(OCH2), 50.4 (NCH2(CH2)16CH3), 39.4 (C-6), 31.8, 30.1, 29.6, 29.5,
29.3, 29.2, 28.9, 26.4, 22.6 (NCH2(CH2)16CH3), 14.0 (N(CH2)17CH3).
HRESIMS calcd for C54H101O10S2N6 [M+H]+: 1057.7021, found:
1057.7053.
HRESIMS calcd for
466.3596.
C
24H52NO5S [M+NH4]+: 466.3566, found:
1.4. 1-Dodecane-4-(6-thio-b-D-galactopyranosyloxymethyl)-
[1,2,3]-triazole (3)
Sodium (11 mg, 0.497 mmol, 4 equiv) was added to a solution of
peracetate 13 (76 mg, 0.124 mmol, 1 equiv) in anhyd MeOH
(12 mL) and the reaction was left to proceed (1 h) and worked up
as described Section 1.2 for the preparation of compound 1. Glyco-
lipid analogue 3 (55 mg, quant.) was obtained pure as a slightly
1.6. 6-S-Acetyl-6-thio-
a,b-D-galactopyranose (6)
The known25 1:2,3:4-di-O-isopropylidene-6-S-acetyl-6-thio-
a
,b- -galactopyranose 5 (1.01 g, 3.18 mmol) was dissolved in a
D
mixture of 2:3:5 H2O–AcOH–TFA (30 mL) and left at rt for 1 h.
The mixture was diluted with toluene (30 mL), solvents were evap-
orated and the residue was co-concentrated with toluene (2 ꢂ
30 mL). Chromatography (EtOAc–MeOH–H2O, 90:6:4) of the resi-
yellowish foam. [
a
]
D
ꢁ4.5 (c 1.0, MeOH). 1H NMR (400 MHz,
CD3OD): d 8.01 (s, 1H, @CH), 4.95 (d, 1H, J = 12.5 Hz, OCHaHb),
4.77 (d, 1H, J = 12.5 Hz, OCHaHb), 4.42–4.32 (m, 3H, H-1,
NCH2(CH2)10CH3, 3.92 (d, 1H, J = 2.6 Hz, H-4), 3.57–3.43 (m, 3H,
H-2, H-3, H-5), 2.81 (dd, 1H, J = 7.2, 13.6 Hz, H-6a), 2.67 (dd, 1H,
J = 6.6, 13.6 Hz, H-6b), 1.88 (t, 2H, J = 7.2 Hz, NCH2CH2(CH2)9CH3),
1.38–1.22 (m, 18H, NCH2CH2(CH2)9CH3), 0.88 (t, 3H, J = 6.6 Hz,
due gave hemiacetal 6 (718 mg, 95%,
1H NMR (400 MHz, CD3OD): d 5.09 (d, 1H, J = 3.2 Hz, H-1
(dd, 1H, J = 3.7, 3.8 Hz, H-1b), 3.98 (t, 1H, J = 6.7 Hz, H-5
(d, 1H, J = 1.7 Hz, H-4
, H-3 ), 3.49 (td, 1H, J = 7.3, 0.9 Hz, H-5b), 3.45–3.39 (m, 2H,
H-2b, H-3b), 3.19–3.02 (m, 4H, H-6 ,b), 2.31 (s, 6H, SCOCH3- ,b).
13C NMR (100 MHz, CD3OD): d 197.2 (C@O), 98.7 (C-1b), 94.2 (C-
a/b ratio 1:1) as a white foam.
a
), 4.38
a), 3.83
a
), 3.78 (s, 1H, H-4b), 3.75–3.67 (m, 2H, H-
N(CH2)11CH3). 13C NMR (100 MHz, CD3OD):
d
145.7 (C@CH),
2a
a
125.2 (C@CH), 104.2 (C-1), 78.1 (C-5), 74.8 (C-3), 72.2 (C-2), 70.2
(C-4), 63.2 (OCH2), 51.4 (NCH2(CH2)10CH3), 33.0, 31.3, 30.7, 30.6,
a
a

2728
M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
1
a
), 75.2 (C-5b), 74.9, 73.5 (C-2b, C-3b), 71.9 (C-4
71.2, 70.2 (C-2 , C-3 ), 70.4 (C-5 ), 30.7, 30.6 (C-6
(SCOCH3-
,b). HRESIMS calcd for C8H14O6SNa [M+Na]+: 261.0409,
a
), 71.2 (C-4b),
1.9. Octadecyl 2,3,4-tri-O-acetyl-6-S-acetyl-6-thio-b-D-
galactopyranoside (9)
a
a
a
a,b), 30.4
a
found: 261.0407.
Octadecanol (475 mg, 1.76 mol, 5 equiv) was glycosylated with
bromide 7 (150 mg, 0.351 mmol, 1 equiv) under Hg(CN)2 (133 mg,
0.527 mmol, 1.5 equiv) activation as described above Section 1.8
for the synthesis of glycoside 8. After work up (as described Section
1.8), chromatography (EtOAc–hexanes, 2:8) of the residue gave the
octadecyl glycoside 9 pure (165 mg, 76%) as a white amorphous
1.7. 2,3,4-Tri-O-acetyl-6-S-acetyl-6-thio-a-D-galactopyranosyl
bromide (7)
Hemiacetal 6 (148 mg, 0.624 mmol) was dissolved in a mixture
Ac2O–pyridine (1:1, 2 mL) and the solution was stirred at 50 °C for
1.5 h. The solvents were co-evaporated with toluene (2 ꢂ 3 mL)
and a solution of the residue in CH2Cl2 (15 mL) was washed succes-
sively with 2 M HCl (3 ꢂ 15 mL) and satd aq NaHCO3 (3 ꢂ 15 mL).
The aq layers were re-extracted with CH2Cl2 (2 ꢂ 15 mL) and the
combined organic layers were dried and concentrated. The crude
peracetylated intermediate was obtained as a yellowish foam
(204 mg, 80%), dried overnight and dissolved in anhyd CH2Cl2
(2.5 mL) under N2. A solution of HBr in AcOH (33%, 1 mL) was
added dropwise to the reaction mixture which was stirred for
30 min at rt, diluted with CH2Cl2 (15 mL) and quickly washed with
satd aq NaHCO3 (40 mL). The aq layer was re-extracted with CH2Cl2
(2 ꢂ 20 mL) and the combined organic layers were dried and con-
centrated. Chromatography (EtOAc–hexanes, 4:6) of the residue
powder. [a]
+19.5 (c 1.0, CH2Cl2). 1H NMR (400 MHz, CDCl3): d
D
5.38 (d, 1H, J = 2.7 Hz, H-4), 5.15 (dd, 1H, J = 8.0, 10.4 Hz, H-2), 4.95
(dd, 1H, J = 3.4, 10.5 Hz, H-3), 4.39 (d, 1H, J = 8.0 Hz, H-1), 3.83 (m,
1H, OCHaHb(CH2)16CH3), 3.63 (td, 1H, J = 0.8, 7.0 Hz, H-5), 3.42
(m, 1H, OCHaHb(CH2)16CH3), 3.09 (dd, 1H, J = 7.0, 13.9 Hz, H-6a),
3.02 (dd, 1H, J = 7.1, 13.8 Hz, H-6b), 2.32 (s, 3H, SCOCH3), 2.14,
2.02, 1.95 (3s, 9H, OCOCH3), 1.55 (m, 2H, OCH2CH2(CH2)15CH3),
1.33–1.20 (m, 30H, OCH2CH2(CH2)15CH3), 0.85 (t, 3H, J = 6.6 Hz,
O(CH2)17CH3). 13C NMR (100 MHz, CDCl3): d 194.7, 170.3, 170.1,
169.4 (C@O), 101.2 (C-1), 72.0 (C-5), 71.1 (C-3), 70.3 (OCH2(CH2)16
-
CH3), 68.9 (C-2), 68.0 (C-4), 31.9, 29.7, 29.6, 29.4, 29.3, 25.8, 22.7
(OCH2(CH2)16CH3), 30.4 (SCOCH3), 28.6 (C-6), 20.7, 20.6 (OCOCH3),
14.1 (O(CH2)17CH3). HRESIMS calcd for C32H60NO9S [M+NH4]+:
634.3989, found: 466.4033.
gave the pure bromide 7 (168 mg, 63%) as a brownish syrup. [
a]
D
+213 (c 1.0, CH2Cl2), lit.27 +197 (c 1.1, CHCl3). 1H NMR
½
a 2D5
ꢃ
1.10. 2-Propynyl 2,3,4-tri-O-acetyl-6-S-acetyl-6-thio-b-D-galacto-
(400 MHz, CDCl3): d 6.64 (d, 1H, J = 3.7 Hz, H-1), 5.48 (dd, 1H,
J = 1.1, 3.2 Hz, H-4), 5.34 (dd, 1H, J = 3.2, 10.6 Hz, H-3), 4.97 (dd,
1H, J = 3.9, 10.6 Hz, H-2), 4.23 (t, 1H, J = 7.1 Hz, H-5), 3.15 (dd,
1H, J = 7.2, 13.9 Hz, H-6a), 2.95 (dd, 1H, J = 7.0, 13.9 Hz, H-6b),
2.31 (s, 3H, SCOCH3), 2.14, 2.07, 1.97 (3s, 9H, OCOCH3 ꢂ 3). 13C
NMR (100 MHz, CDCl3): d 194.0, 170.0, 170.0, 169.7 (C@O), 88.2
(C-1), 72.4 (C-5), 68.2 (C-3), 67.7 (C-4), 67.6 (C-2), 30.4 (SCOCH3),
27.8 (C-6), 20.7, 20.6, 20.5 (OCOCH3 ꢂ 3).
pyranoside (10)
A mixture of propargyl alcohol (96.7
and N,N-tetramethylurea (99.3 L, 0.830 mmol, 1.5 equiv) in anhyd
lL, 1.66 mmol, 3 equiv)
l
CH2Cl2 (2 mL) containing silver trifluoromethanesulfonate
(156.5 mg, 0.609 mmol, 1.1 equiv) was cooled to ꢁ40 °C under
N2. A solution of bromide 7 (238 mg, 0.554 mmol, 1 equiv) in an-
hyd CH2Cl2 (3.5 mL) was added dropwise to the mixture and after
30 min at ꢁ40 °C the reaction mixture was allowed to warm up to
rt slowly and the reaction was left under stirring for a further 3 h at
rt. The solids were filtered off on CeliteÒ, washed with CH2Cl2
(15 mL) and the combined filtrate and washings were washed with
satd aq NaHCO3 (20 mL). The aq phase was re-extracted with
CH2Cl2 (2 ꢂ 10 mL) and the combined organic layers were dried
and concentrated. Chromatography (EtOAc–hexanes, 3:7) of the
residue gave propagyl glycoside 10 pure as a yellowish oil
1.8. Dodecyl 2,3,4-tri-O-acetyl-6-S-acetyl-6-thio-b-D-galacto-
pyranoside (8)
A solution of dodecanol (327 mg, 1.76 mol, 5 equiv) and bro-
mide 7 (150 mg, 0.351 mmol, 1 equiv) in anhyd toluene (3.5 mL)
containing freshly activated MS 4 Å (175 mg) was stirred under
N2 for 30 min at rt. Hg(CN)2 (133 mg, 0.527 mmol, 1.5 equiv) was
added to the reaction mixture that was then stirred at 40 °C for
22 h. A mixture pyridine–Ac2O (1:1, 2 mL) was added to the mix-
ture which was then heated to 50 °C for 3 h. The reaction mixture
was allowed to cool down to rt, diluted with EtOAc (30 mL) and fil-
tered over a pad of CeliteÒ. The solids were washed with EtOAc
(10 mL) and the combined filtrate and washings were washed with
2 M HCl (3 ꢂ 30 mL) and satd aq NaHCO3 (3 ꢂ 30 mL). The aq
phases were re-extracted with EtOAc (2 ꢂ 15 mL) and the com-
bined organic layers were dried and concentrated. Chromatogra-
phy (EtOAc–hexanes, 2:8) of the residue gave the dodecyl
glycoside 8 pure as a white amorphous powder (142 mg, 76%).
(125 mg, 56%). [
a
]
D ꢁ2.0 (c 1.0, CH2Cl2). 1H NMR (600 MHz, CDCl3):
d 5.39 (d, 1H, J = 3.3 Hz, H-4), 5.17 (dd, 1H, J = 8.1, 10.3 Hz, H-2), 5.0
(dd, 1H, J = 3.3, 10.3 Hz, H-3), 4.68 (d, 1H, J = 8.0 Hz, H-1), 4.38 (t,
2H, J = 2 Hz, OCH2C„CH), 3.69 (t, 1H, J = 7.1 Hz, H-5), 3.1 (dd, 1H,
J = 6.9, 13.9 Hz, H-6a), 3.02 (dd, 1H, J = 7.1, 13.9 Hz, H-6b), 2.44 (t,
1H, J = 2.1 Hz, C„CH), 2.32 (s, 3H, SCOCH3), 2.14, 2.04, 1.95 (3s,
9H, OCOCH3 ꢂ 3). 13C NMR (125 MHz, CDCl3): d 194.6, 170.3,
170.1, 169.6 (C@O), 98.6 (C-1), 78.3 (C„CH), 75.3 (C„CH), 72.3
(C-4), 71 (C-2), 68.5 (C-3), 67.9 (C-5), 55.9 (OCH2C„CH), 30.5
(SCOCH3), 28.6 (C-6), 20.8, 20.7, 20.6 (OCOCH3). HRESIMS calcd
for C17H22O9SNa [M+Na]+: 425.0882, found: 425.0898.
[a]
+23.2 (c 1.0, CH2Cl2). 1H NMR (400 MHz, CDCl3): d 5.38 (dd,
D
1H, J = 0.6, 3.1 Hz, H-4), 5.15 (dd, 1H, J = 8.0, 10.5 Hz, H-2), 4.95
(dd, 1H, J = 3.4, 10.5 Hz, H-3), 4.39 (d, 1H, J = 8 Hz, H-1), 3.86 (m,
1H, OCHaHb(CH2)10CH3), 3.63 (td, 1H, J = 0.8, 7.4 Hz, H-5), 3.45
(m, 1H, OCHaHb(CH2)10CH3), 3.08 (dd, 1H, J = 7.0, 13.8 Hz, H-6a),
3.02 (dd, 1H, J = 7.1, 13.9 Hz, H-6b), 2.31 (s, 3H, SCOCH3), 2.14,
2.02, 1.94 (3s, 9H, OCOCH3), 1.55 (m, 2H, OCH2CH2(CH2)9CH3),
1.25 (m, 18H, OCH2CH2(CH2)9CH3), 0.85 (t, 3H, J = 6.8 Hz,
O(CH2)11CH3). 13C NMR (100 MHz, CDCl3): d 194.7, 170.4, 170.1,
169.4 (C@O), 101.2 (C-1), 72.0 (C-5), 71.1 (C-3), 70.3
(OCH2(CH2)10CH3), 68.9 (C-2), 68.0 (C-4), 31.9, 29.6, 29.4, 29.3,
28.6, 22.7 (OCH2(CH2)10CH3), 30.4 (SCOCH3), 25.8 (C-6), 20.7, 20.6
(OCOCH3), 14.1 (O(CH2)11CH3). HRESIMS calcd for C26H44O9SNa
[M+Na]+: 555.2604, found: 555.2580.
1.11. 1-Azido-dodecane (11)
PPh3 (2.89 g, 11 mmol, 4.1 equiv), I2 (2.12 g, 8.34 mmol,
3.1 equiv) and imidazole (751 mg, 11 mmol, 4.1 equiv) were added
at rt to a solution of dodecanol (501 mg, 2.7 mmol, 1 equiv) in tol-
uene (70 mL). The reaction was heated to reflux for 2 h, then al-
lowed to cool down to rt and satd aq NaHCO3 (70 mL) was
added. The biphasic mixture was stirred for 5 min and I2 was added
until the organic phase remained brown. A 20% aq Na2S2O3 solu-
tion was then added to the reaction mixture until it became colour-
less and the biphasic mixture was transferred to a separatory
funnel. The aq layer was drained and the organic phase was
washed with water (3 ꢂ 70 mL), dried and concentrated.

M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
2729
Chromatography (EtOAc–hexanes, 1:9) of the residue gave the
1.14. 1-Octadecane-4-(2,3,4-tri-O-acetyl-6-S-acetyl-6-thio-b-D-
pure 1-iodo-dodecane (606 mg, 76%) intermediate as a yellowish
oil. The iodide (527 mg, 1.8 mmol, 1 equiv) was dissolved in anhyd
DMF (25 mL) and NaN3 (694 mg, 11 mmol, 6 equiv) was added to
the solution. The reaction mixture was heated to 60 °C for 20 h,
allowed to cool down to rt and diluted with water (25 mL). The
mixture was extracted with Et2O (3 ꢂ 50 mL) and the organic
phases were washed with water (3 ꢂ 50 mL), dried and concen-
trated. Chromatography (EtOAc–hexanes, 2:98) of the residue gave
the azido 11 (347 mg, 92%) pure as a colourless oil. 1H NMR
(600 MHz, CDCl3): d 3.23 (t, 2H, J = 7.0 Hz, CH2N3), 1.58 (m, 2H,
J = 7.0 Hz, CH2CH2N3), 1.35 (2H, m, CH2CH2CH2N3), 1.25 (16H, m,
CH3(CH2)8CH2CH2CH2N3), 0.86 (t, 3H, J = 6.8 Hz, CH3). 13C NMR
(125 MHz, CDCl3): d 51.5 (CH2N3), 31.9, 29.6, 29.5, 29.3, 29.2,
28.8, 26.7, 22.6 (CH3(CH2)10CH2N3), 14.1 (CH3). The NMR data is
in accordance to the literature.35
galactopyranosyloxy-methyl)-[1,2,3]-triazole (14)
Propargyl glycoside 10 (57 mg, 0.142 mmol, 1 equiv) and 1-
azido-octadecane 12 (46 mg, 0.156 mmol, 1.1 equiv) were reacted
as described Section 1.13 for the synthesis of cyclo-adduct 13. After
work up as described above Section 1.13, chromatography (EtOAc–
hexanes, 4:6) of the residue gave cyclo-adduct 14 (58 mg, 59%) pure
as a colourless amorphous glass. [a]
+6.2 (c 1.0, CH2Cl2). 1H NMR
D
(400 MHz, CDCl3): d 7.48 (s, 1H, @CH), 5.38 (dd, 1H, J = 0.5, 2.9 Hz,
H-4), 5.17 (dd, 1H, J = 8.0, 10.4 Hz, H-2), 4.96 (m, 2H, H-3, OCHaHb),
4.78 (d, 1H, J = 12.5 Hz, OCHaHb), 4.58 (d, 1H, J = 8.0 Hz, H-1), 4.30
(t, 2H, J = 6.9 Hz, NCH2(CH2)16CH3), 3.69 (t, 1H, J = 7.0 Hz, H-5),
3.10 (dd, 1H, J = 6.8, 13.9 Hz, H-6a), 3.01 (dd, 1H, J = 7.2, 13.9 Hz,
H-6b), 2.32 (s, 3H, SCOCH3), 2.13, 1.95, 1.93 (3s, 9H, OCOCH3), 1.86
(t, 2H, J = 7.0 Hz, NCH2CH2(CH2)15CH3), 1.32–1.17 (m, 30H, NCH2-
CH2(CH2)15CH3), 0.83 (t, 3H, J = 6.6 Hz, N(CH2)17CH3). 13C NMR
(100 MHz, CDCl3): d 194.5, 170.3, 170.0, 169.5 (C@O), 144.1 (C@CH),
122.4 (C@CH), 100.3 (C-1), 72.2 (C-5), 71.0 (C-3), 68.7 (C-2), 67.9
(C-4), 63.0 (OCH2), 50.4 (NCH2(CH2)16CH3), 31.9, 30.3, 29.6, 29.5,
29.4, 29.3, 29.0, 26.5, 22.6 (NCH2(CH2)16CH3), 30.5 (SCOCH3), 28.6
(C-6), 20.7, 20.5 (OCOCH3), 14.1 (N(CH2)17CH3). HRESIMS calcd for
C35H60O9SN3 [M+H]+: 698.4050, found: 698.4057.
1.12. 1-Azido-octadecane (12)
Octadecanol (504 mg, 1.86 mmol, 1 equiv) in toluene (50 mL)
was converted into the corresponding iodide using PPh3 (2.0 g,
7.6 mmol, 4 equiv), I2 (1.47 g, 5.8 mmol, 3 equiv) and imidazole
(520 mg, 7.6 mmol, 4 equiv) as described above Section 1.11 for
thesynthesisof 1-iodo-dodecane. Thereaction wasworkedup asde-
scribed Section 1.11 and chromatography (EtOAc–hexanes, 2:98)
gave the pure 1-iodo-octadecane (579 mg, 82%) as a yellowish oil.
It was converted (553 mg, 1.45 mmol, 1 equiv) to the corresponding
1-azido octadecane as described above Section 1.11 for the synthesis
of 1-azido-dodecane and after work up and chromatography
(EtOAc–hexanes, 2:98) the 1-azido-octadecane 12 (409 mg, 95%)
was isolated pure as a colourless oil. 1H NMR (400 MHz, CDCl3): d
3.23 (t, 2H, J = 7.0 Hz, CH2N3), 1.58 (m, 2H, J = 6.8 Hz, CH2CH2N3),
1.37–1.20 (30H, m, CH3(CH2)15CH2CH2N3), 0.86 (t, 3H, J = 6.7 Hz,
CH3). 13C NMR (100 MHz, CDCl3): d 51.5 (CH2N3), 31.9, 29.7, 29.6,
29.5, 29.4, 29.2, 28.8, 26.7, 22.7 (CH3(CH2)16CH2N3), 14.1 (CH3). The
NMR data is in accordance to the literature.36
1.15. Attenuated total reflection (ATR) spectroscopy on films of
randomly oriented compounds 1 and 3
Sample films were deposited onto the internal reflection ele-
ment by evaporation of a 2 mg mLꢁ1 solution of either compound
1 or 3 in MeOH. ATR spectra were collected at room temperature
on a Nicolet Nexus 870 spectrometer (Madison, WI) equipped with
an MCT-A detector (Nicolet, Madison, WI) and a VeeMax II variable
angle specular reflectance accessory (Pike Technologies, Madison,
WI). The instrumental resolution was 4 cmꢁ1. Spectra were col-
lected at a 45° incident angle with a 45° face angle ZnSe internal
reflection element (Pike Technologies, Madison, WI).
1.13. 1-Docecane-4-(2,3,4-tri-O-acetyl-6-S-acetyl-6-thio-b-D-
galactopyranosyloxy-methyl)-[1,2,3]-triazole (13)
1.16. Infrared reflection absorption spectroscopy (IRRAS) on
self-assembled mono layers of 1 and 3 on gold
Propargyl glycoside 10 (114 mg, 0.284 mmol, 1 equiv) and 1-azi-
do-dodecane 11 (66 mg, 0.312 mmol, 1.1 equiv) were dissolved in a
mixture THF-water (11:3, 14 mL) and a 1 M aq solution of sodium
Self-assembled monolayers were obtained by incubating a gold
slide in a 2 mg mLꢁ1 solution of either compound 1 or 3 in MeOH
for 24 h. The gold slide was then rinsed, first with methanol and
then with water. IRRAS spectra were collected at room tempera-
ture on a Nicolet Nexus 870 spectrometer (Madison, WI) equipped
with an MCT-A detector (Nicolet, Madison, WI), a VeeMax II vari-
able angle specular reflectance accessory (Pike Technologies, Mad-
ison, WI), and a ZnSe wire-grid polarizer (Pike Technologies,
Madison, WI). The instrumental resolution was 4 cmꢁ1. For the
CH stretching region, the incident angle was 70°. For the 1500–
1000 cmꢁ1 region, the incident angle was 80°.
ascorbate (567
lL, 0.567 mmol, 2 equiv) followed by a 0.1 M aq
solution of copper(II) sulfate pentahydrate (284
lL, 0.284 mmol,
0.1 equiv) were added. The reaction mixture was stirred at rt for
23 h and the solvents were evaporated. The residue was dissolved
in EtOAc (20 mL), washed with satd aq NaHCO3 (3 ꢂ 20 mL) and
the aq phases were re-extracted with EtOAc (2 ꢂ 10 mL). The com-
bined organic layers were dried, concentrated and chromatography
(EtOAc–hexanes, 4:6) of the residue gave the cyclo-adduct 13
(97 mg, 55%) pure as a colourless amorphous glass. [a]D +1.6 (c 1.0,
CH2Cl2). 1H NMR (400 MHz, CDCl3): d 7.48 (s, 1H, @CH), 5.38 (d,
1H, J = 2.9 Hz, H-4), 5.18 (dd, 1H, J = 8.0, 10.4 Hz, H-2), 4.96 (m, 2H,
H-3, OCHaHb), 4.78 (d, 1H, J = 12.5 Hz, OCHaHb), 4.58 (d, 1H,
J = 8.0 Hz, H-1), 4.30 (t, 2H, J = 7.0 Hz, NCH2(CH2)10CH3), 3.69 (t, 1H,
J = 6.9 Hz, H-5), 3.10 (dd, 1H, J = 6.8, 13.9 Hz, H-6a), 3.01 (dd, 1H,
J = 7.2, 13.9 Hz, H-6b), 2.32 (s, 3H, SCOCH3), 2.14, 1.95, 1.94 (3s, 9H,
OCOCH3), 1.86 (t, 2H, J = 7.0 Hz, NCH2CH2(CH2)9CH3), 1.31–1.19
(m, 18H, NCH2CH2(CH2)9CH3), 0.84 (t, 3H, J = 6.6 Hz, N(CH2)11CH3).
13C NMR (100 MHz, CDCl3): d 194.5, 170.2, 170.0, 169.5 (C@O),
144.0 (C@CH), 122.4 (C@CH), 100.2 (C-1), 72.2 (C-5), 70.9 (C-3),
68.7 (C-2), 67.9 (C-4), 63.0 (OCH2), 50.3 (NCH2(CH2)10CH3), 31.8,
30.3, 29.5, 29.3, 28.9, 26.4, 22.6 (NCH2(CH2)10CH3), 30.4 (SCOCH3),
28.5 (C-6), 20.8, 20.7, 20.5 (OCOCH3), 14.0 (N(CH2)11CH3). HRESIMS
calcd for C29H48O9SN3 [M+H]+: 614.3131, found: 614.3104.
Acknowledgements
The authors are grateful for financial support by NSERC. We also
wish to thank Professor Jacek Lipkowski (Department of Chemistry,
University of Guelph) for the access to IRRAS and ATR as well as for
scientific discussions.
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.carres.2010.09.035.

2730
M. Guillemineau et al. / Carbohydrate Research 345 (2010) 2723–2730
20. Kycia, A. H. Ph.D. Thesis, University of Guelph, August 2010.
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