Assessing the Optimal Deoxygenation Pattern of Dodecyl Glycosides for Antimicrobial Activity Against Bacillus anthracis

Article abstract of DOI:10.1002/ejoc.201801764

The discovery of the bactericide dodecyl 2,6-dideoxypyranoside reorganizing membrane phospholipid matrix of Bacillus species into a hexagonal phase, encouraged further research on glycone deoxygenation/bioactivity relationship. We now describe expedient syntheses of new 2-, 3-, 4-deoxy, 2,3- and 3,4-dideoxy glycosides in moderate to good yields. Interestingly, Amberlyst 15 is a key protagonist, efficiently applied for the transacetalation of alkyl deoxy glycosides and for ring contraction to access regioselectively hexofuranosides. The 2-deoxy-d-arabino pyranoside affords the higher MIC values against two Bacillus spp. and Enterococcus faecalis, while a 4-fold decrease or higher was found by inversion of configuration or by deoxygenation at C-3. While 2,3- and 3,4-dideoxygenation do not improve bioactivity, the 4,6-dideoxy-α-d-xylo-hexopyranoside remains a promising glycoside, presenting low MIC values for all species tested, and low cytotoxicity in intestinal and liver cell models.

Full text of DOI:10.1002/ejoc.201801764

A Journal of
Accepted Article
Title: Assessing the optimal deoxygenation pattern of dodecyl
glycosides for antimicrobial activity against Bacillus anthracis
Authors: Amelia Pilar Rauter, Catarina Dias, Alice Martins, Ana
Pelerito, Maria Conceição Oliveira, Marialessandra Contino,
and Nicola Colabufo
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201801764
Link to VoR: http://dx.doi.org/10.1002/ejoc.201801764
Supported by

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
Assessing the optimal deoxygenation pattern of dodecyl
glycosides for antimicrobial activity against Bacillus anthracis
Catarina Dias,[a,b] Alice Martins,[a,b] Ana Pelerito,[c] Maria C. Oliveira,[b] Marialessandra Contino,[d] Nicola
A. Colabufo,[d,e] and Amélia P. Rauter*[,a,b]
Dedicated to the memory of Prof. Dr. Derek Horton in recognition of his outstanding contributions in the subject of industrial
carbohydrate chemistry
Abstract: The discovery of the bactericide dodecyl 2,6-
dideoxypyranoside reorganizing membrane phospholipid matrix of
Bacillus species into a hexagonal phase, encouraged further research
on glycone deoxygenation/bioactivity relationship. We now describe
expedient syntheses of new 2-, 3-, 4-deoxy, 2,3- and 3,4-dideoxy
glycosides in moderate to good yields. Interestingly, Amberlyst 15 is
a key protagonist, efficiently applied for the transacetalation of alkyl
deoxy glycosides and for ring contraction to access regioselectively
hexofuranosides. The 2-deoxy-D-arabino pyranoside affords the
higher MIC values against two Bacillus spp. and Enterococcus
faecalis, while a 4-fold decrease or higher was found by inversion of
configuration or by deoxygenation at C-3. While 2,3- and 3,4-
dideoxygenation do not improve bioactivity, the 4,6-dideoxy-α-D-xylo-
hexopyranoside remains a promising glycoside, presenting low MIC
values for all species tested, and low cytotoxicity in intestinal and liver
cell models.
affecting animals and humans, and a serious bioterrorism
threat.[1] The latter is responsible for food poisoning and generate
biofilms, particularly important in implanted medical devices,
triggering chronic wounds, persistent infections and creating a
physical barrier to antibiotics.[2] The apprehension with the
emergence of antibiotic-resistant bacterial strains led to a
renovated interest in the search for antibiotics exhibiting
structures prone to different mechanisms of action.
In this context, research in carbohydrate-based antibiotics
provides structural diversity and unique physicochemical
properties. In the last decade, our research group has introduced
a new family of alkyl deoxy glycosides, some of which exhibiting
a potent activity against Bacillus spp. Both dodecyl 4,6-dideoxy-
α-D-xylo-hexopyranoside
(1)
and
2,6-α-D-arabino-
hexopyranoside 2 are active against Bacillus spp., in particular B.
cereus and B. anthracis (MIC 12.6 μM for 1, and 50 μM for 2).[3,4]
Surprisingly, the 6-hydroxylated analogue 3 was not active on B.
cereus, although it exhibited surface activity parameters such as
critical micelle concentration, adsorption and aggregation data of
the same order of magnitude as those of compound 2,[3]
suggesting that there is no causal link between surface activity
and the mode of action. Indeed, the unprecedented mode of
action underlying membrane disruption, that results from
Introduction
One of the main societal challenges of the present century is the
unstoppable rise of antimicrobial resistant bacteria. Bacillus
genus comprises a variety of pathogenic species, namely B.
anthracis and B. cereus, which despite the genetic similarity, rise
diverse concerns. The first causes the infectious disease anthrax
membrane
permeabilization
by
local
induction
of
phosphatidylethanolamine reorganization from lamellar to
inverted hexagonal phases may explain this behaviour.[4]
[a]
C. Dias, Dr. A. Martins and Prof. A.P. Rauter
Centro de Química e Bioquímica
Faculdade de Ciências, Universidade de Lisboa
Campo Grande, 1749-016 Lisboa, Portugal
aprauter@fc.ul.pt
https://ciencias.ulisboa.pt/en/perfil/aprauter
C. Dias, Dr. A. Martins, Dr. M. C. Oliveira, and Prof. A.P. Rauter
Centro de Química Estrutural, Universidade de Lisboa
Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Dr. A. Pelerito
Figure 1. Alkyl deoxyglycosides active on Bacillus spp: Dodecyl 4,6-dideoxy-α-
D-xylo-hexopyranoside (1), dodecyl 2,6-dideoxy-α-D-arabino-hexopyranoside
(2) and dodecyl 2-deoxy-α-D-arabino-hexopyranoside (3).
[b]
[c]
Instituto Nacional de Saúde Doutor Ricardo Jorge
Av. Padre Cruz, 1649-016 Lisboa, Portugal
Dr.M. Contino and Prof. N. A. Colabufo
Dipartimento di Farmacia-Scienze del Farmaco
Università degli Studi di Bari
Via Edoardo Orabona, 4, 70125 Bari, Italy
Prof. N. A. Colabufo
Biofordrug
Thus, aiming at recognizing the optimal deoxygenation pattern for
antimicrobial activity, this paper describes a series of analogues
to compounds 1-3 to fully explore the potential of deoxy
glycosides as new antimicrobials.
Synthetic methodologies towards dodecyl 2-, 3-, 4-deoxy,
and 2,3-, 3,4-, and 4,6-dideoxy glycosides were investigated.
Glycoside antimicrobial activity against Bacillus species and
[d]
[e]
Università degli Studi di Bari
Via Edoardo Orabona, 4, 70125 Bari, Italy
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
for this glycosylation reaction. These results are in line with those
obtained by our group with other heterogeneous catalysts,
namely with acid zeolites as promoters of hexopyranose
acetalation.[6] Despite the low yield (28%), this method afforded a
direct access to the thermodinamically less stable furanoside as
a major reaction product, thus allowing to have insights into the
Enterococcus faecalis was assayed and the most promising
structures confronted with in vitro cytotoxicity in intestinal and liver
cell models.
five-membered
vs
six-membered
ring
impact
on
Results and Discussion
bioactivity/selectivity. This reaction outcome prompted us to
develop a second approach to access 16, starting with the
conversion of 3,4,6-tri-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-
hex-1-enitol (17) in the 2,3-unsaturated dodecyl glycosides 18a,b
(scheme 2B). The α-anomer 18a was selectively oxidized with m-
CPBA into epoxide 19, which reduction with LiAlH4 gave the 3-
and 2-deoxy glycosides 16 and 20, in 20% and 33% yield,
respectively. The configuration of the epoxide 19 was first
proposed due to a strong correlation of H-3 with H-4 observed in
the NOESY spectrum, together with the coupling constants J3,4
and J2,3. NMR data of the resulting reduction products allowed
structural assignment of 2-and 3-deoxygenation, in particular the
axial H-3 NMR signal of 16, exhibiting J3ax,4ax=J2ax,3ax=J3ax,3eq=11
Hz.
Chemistry. Synthesis of 4-deoxy glycosides starts by the
transformation of methyl α-D-glucopyranoside to access position
4 free for further manipulation. Conventional benzylidenation,
followed by benzylation of the free positions and selective
benzylidene ring opening affords the substrate which is converted
into a triflate and reduced with tetrabutylammonium borohydride
(Scheme 1). The resulting 4-deoxy glycoside precursor 7 reacts
with dodecan-1-ol, in the presence of Amberlyst 15. This effective
and clean methodology, described by Corma and co-workers for
the conversion of cellulose into biodegradable surfactants,[5] is
herein adapted as an efficient glycochemistry tool, by avoiding
multistep syntheses for the insertion of good leaving groups in
glycosylation donor. Benzyl deprotection gives the anomeric
mixture 8a,b in good yield. 6-Deoxygenation succeeded with
triflation and reduction, since selective tosylation failed to meet
the expectations. The resulting anomers could only be separated
after acetylation to give 9 and 10, isolated by CC. Deacetylation
afforded the target 4,6-dideoxy glycosides 1 and 11 in high yield.
Scheme 2. A. Synthesis of dodecyl 3-deoxy-α-D-ribo-hexopyranoside and -
hexofuranoside, via Fisher glycosylation. a) Tf2O, py, DCM, -10 ºC; b) n-
Bu4NBH4, THF, 72% (over two steps); c) 80% TFA, 90%; d) C12H25OH,
Amberlyst 15, reflux (15, 28%; 16, 8%). B. Synthesis of dodecyl 3-deoxy-α-D-
ribo-hexopyranoside via epoxide. e) C12H25OH, BF3•Et2O; f) NaOMe, MeOH,
18a, 73% (over two steps); 18b, 11% (over two steps) ; g) m-CPBA, NaHCO3,
DCM, 74%; h) LiAlH4, THF (16, 20%; 20, 33%).
Synthesis of the dideoxy glycoside 23 (Scheme 3) was
accomplished by hydrogenation of the benzyl protected Ferrier
product 22a, which was prepared by reacting a benzyl protected
glycal with dodecan-1-ol in the presence of zeolite HY. The
elimination of benzyl alcohol is not common when Lewis acids are
used. However this heterogeneous catalyst is able to protonate
the hard C-3 oxygen, with consequent debenzoxylation and
formation of the delocalized allylic oxycarbenium ion
characteristic of the Ferrier rearrangement, that reacts with the
alcohol to selectively afford the thermodinamically more stable
anomer.[6] Nevertheless, the approach using a benzyl protected
starting material is less appealing than the one starting from acetyl
protected glycals, as an overall yield of 43% is obtained for 22a,b
with low selectivity for the α-anomer.
Scheme 1. Synthesis of dodecyl 4-deoxy and 4,6-dideoxy-D-xylo-
hexopyranosides. a) PhCH(OMe)2, p-TsOH, DMF, 60 ºC, 240 mbar, 94%; b)
BnBr, NaH, DMF, 82%; c) NaBH3CN, I2, MeCN, 77%; d) Tf2O, py, DCM, -10ºC;
e) n-Bu4NBH4, THF, 83% (over two steps); f) C12H25OH, Amberlyst 15; g) Et3SiH,
10% Pd/C, EtOAc, 80% (over two-steps); h) Tf2O, py, DCM, -10 ºC; i) LiAlH4,
THF; j) Ac2O, py, DMAP; (41% over 3 steps); k) NaOMe, MeOH (94-96%).
Deoxygenation of position 3 is also investigated (Scheme 2). In
the first approach, the 3-deoxy sugar 14 is prepared via triflation
and reduction of diacetoneglucose (DAG) followed by
isopropylidene hydrolysis (Scheme 2A). It is then used directly as
a glycosyl donor in Fisher glycosylation of dodecan-1-ol. As acid
promoters, Amberlyst 15, IR-120, dowex-50R, and the clay
montmorillonite were tested. With this approach pyranoside 16 is
the minor product, isolated only up to 10%. Interestingly, the major
reaction product embodies a furanose ring, and the highest yield
is obtained with Amberlyst 15 as promoter, revealing its versatility
Deoxygenation of positions 3 and 4 (Scheme 4) is effectively
achieved by selectively protecting positions 2 and 6 with the
pivaloyl group, triflation of the remaining free hydroxy groups and
reaction with tetrabutylammonium borohydride. The methyl 3,4-
dideoxy glycoside 25 is isolated in 29% yield, with the concomitant
formation of the 4-deoxy derivative 26 in 33% yield. Reaction of
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
25 with dodecan-1-ol in the presence of Amberlyst 15 affords the
dodecyl glycosides that, after deacylation, give the target
molecules 27a and 27b.
11
>405
96
>405
96
>405
96
>405
96
>405
96
50
n.d.
n.d.
100
n.d.
100
n.d.
n.d.
4,6-dideoxy, β
15
100
50
3-deoxy, Fur
16
48
48
48
48
48
3-deoxy, Pyr
20
48
48
48
96
96
>50
100
>50
n.d.
2-deoxy, Pyr
23
2,3-dideoxy
50
50
50
50
50
27
3,4-dideoxy
101
25
101
25
101
25
101
25
101
25
Scheme 3. Synthesis of dodecyl 2,3-dideoxy-D-erythro-hexopyranoside (23). a)
C12H25OH, HY, DCE, 43%; b) Et3SiH 10% Pd/C, 51%.
Ref [a]
[a] Chloramphenicol was used as reference.
Interestingly, when only position 4 is deoxygenated (compound
8a), a four-fold decrease in activity is found, in line with previous
findings.[4] This result can be rationalized as the hydroxy group at
position 6 is more readily solvated by water molecules, making
this glycoside less lipophilic, with a negative impact on its
interaction with the phosphatidylethanolamine enriched
phospholipid membranes. Apart from these observations, there is
no clear tendency regarding the effect of the deoxygenated
position by considering the 2-, 3- and 4-deoxy glycosides
(compounds 8a, 16 and 20), all of them presenting the same MIC
values. Dideoxygenated compound 23 present virtually the same
antimicrobial activity against B. anthracis strains, while the 3,4-
deoxy compound 27a is the less active one of the group. It is also
interesting to note that pyranoside 16 is active at 48 µM while its
furanose analogue (15) is twice less active. The difficult structure-
activity relationship underlying these results is indeed a well-
known characteristic of membrane-targeting antimicrobial
compounds.[7]
The cell viability of intestinal (Caco-2) and hepatic (HepG2)
cell models was assessed by the MTT assay, after 48 h of
incubation time. With the exception of compounds 1 and 3, most
compounds showed toxicity values in Caco 2 cells of the same
order of magnitude, or higher, than those exhibited for their
bactericide activity. Only compounds 1, the most active one, and
the analogues 2, 16 and 23 were selected to be tested in HepG2
cells. The IC50 of all tested compounds is 50 µM or above, with
compounds 1, 16 and 23 being the less toxic for intestinal cells.
Compound 1 presented an IC50 four times its MIC value for Caco-
2 cells, and more than eight times the MIC value for HepG2 cells
making it the most promising lead for further development.
Scheme 4. Synthesis of dodecyl 3,4-dideoxy-D-erythro-hexopyranosides. a)
PivCl, py, DCM, 65%; b) Tf2O, py, DCM, -10 ºC; c) n-Bu4NBH4, THF, 29% (over
two steps); d) C12H25OH, Amberlyst15; e) KOH, H2O:MeOH (27, 36%; 28, 15%,
over two steps).
Antimicrobial activity and cytotoxicity. Antimicrobial activity
over three B. anthracis strains, B. cereus and E. faecalis is
evaluated by the Müller-Hinton agar dilution method, according to
CLSI guidelines (Table 1). Compound 1, deoxygenated in
positions 4 and 6, is the most active one, presenting a potent
antimicrobial activity in all tested strains. The lack of activity of its
beta-anomer (11) confirms, once again, the tendency already
reported by us for β-hexopyranosides.[3, 4]
Table 1. Antibacterial activity expressed in MIC values and cytotoxicity (IC50).
Cytotoxicity
(IC50) in µM
MIC in µM
Compound
B. anthracis
E.
B.
Caco-2 Hep G2
faecalis cereus
Sterne
12.6
50
pathog.
12.6
50
Ovine
12.6
50
1[4]
12.6
50
12.6
25
50
100
50
>100
50
4,6-dideoxy, α
Conclusions
2[4]
2,6-dideoxy, α
Aiming at recognizing the role of deoxygenation pattern for
optimization of dodecyl glycoside antimicrobial activity, mono-
and dideoxy dodecyl glycosides were successfully synthesized in
moderate to good yields. The usefulness of Amberlyst 15 as
glycosylation promoter is patent, particularly for the
3[3]
2-deoxy
386
48
12
12
12
386
48
n.d.
n.d.
8a
48
48
48
n.d.
4-deoxy, Pyr
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
Samples were analyzed by flow injection analysis (FIA) using a isocratic
gradient 50 A:50 B of 0.1% formic acid in water (A) and 0.1% of formic acid
in acetonitrile (B), at a flow rate of 5 µLmin-1 over 15 min. Calibration of the
TOF analyzer was performed with a calibrant solution of sodium formate
10 mM. The full scan mass spectra were acquired over a mass range of
50-1000 m/z at a spectra rate of 0.2 Hz. Data was processed using Data
Analysis 4.2 software.
transacetalation of methyl glycosides (Schemes 2 and 4) to easily
access the dodecyl glycosides. This heterogeneous catalyst,
alternatively to the Lewis acids commonly used, is recovered,
environmentally friendly, and affords stereoselectively the most
active α-anomer. Its successful use with the free sugar avoids
additional protection and deprotection steps required when other
Lewis acid catalysts are applied, leading to the regioselective
formation of hexofuranosides by a single reaction step, also an
achievement within synthetic methodologies known for such
structures. In addition, catalyst removal by filtration facilitates
reaction work up and consequently the isolation of both the
hexopyranoside/hexofuranoside isomers, that is much easier
than when other catalysts are used. Deoxygenation carried out by
triflation and reaction with tetrabutylammonium borohydride has
proven as an efficient route for the synthesis of the 3-, 4-, 4,6- and
3,4- deoxygenated compounds.
Dodecyl 2-, 3-, 4-deoxy, and 2,3-, 3,4-, and 4,6-dideoxy
glycosides were tested for their antimicrobial activity. As it is
appanage of membrane-targeting antimicrobial compounds, the
structure-activity relationship underlying the antimicrobial results
was not so clear, as the impact of the deoxygenation position or
the number of deoxygenated positions was not linear. The 2-
deoxy-D-arabino-pyranoside shows a promising MIC value for B.
pathogenic, B. ovine and E. faecalis but is not active for B. cereus
and B. sterne. Nevertheless, the configuration at C-3 is relevant
for the bioactivity over these species, as a four fold decrease in
bioactivity, or higher is found when glycone configuration at C-3
is inverted or embodies a 3-deoxygenation. The 2,3 and 3,4-
dideoxygenation pattern do not seem to improve bioactivity, while
4,6-dideoxygenation rises as the most promising structural
feature, leading to compound 11, active over all microbes tested,
and presenting an IC50 four/eight times its MIC value for Caco-2
cells, and HepG2 cells, respectively.
Methyl 2,3-Di-O-benzyl-4,6-O-benzylidene-α-D-glucopyranoside (5).
To a solution of methyl 4,6-O-benzylidene-α-D-glucopyranoside[8] (3 g,
10.6 mmol) in DMF (200 mL), NaH (60% oil suspension, 2.84 g, 42.4 mmol,
4 equiv.) was carefully added at 0 ºC and the reaction was stirred for 15
min. Then, benzyl bromide (5.1 mL, 42.4 mmol, 4 equiv.) was added and
the reaction was stirred at room temperature overnight. The reaction was
quenched by pouring it into cooled water (200 mL) and extracted with DCM
(3×100 mL). Organic phases were combined, washed with saturated
aqueous sodium hydrogen carbonate and dried with MgSO4. After filtration
and concentration under reduced pressure, the residue was purified by CC
(hexhex/EtOAc 5:1), affording compound 5 as a white solid in 82% yield
(4.03 g). Physical and spectroscopic data were in agreement with this
structure, previously reported in the literature.[9]
Methyl 2,3,6-tri-O-benzyl-α-D-glucopyranoside (6). To a solution of
compound 5 (3.00 g, 6.49 mmol) in acetonitrile (60 mL) containing 4Å
molecular sieves (ca. 200 mg), sodium cyanoborohydride (2.037 g, 32.4
mmol, 5 equiv.) was added. Then, molecular iodine (3,781 g, 14.9 mmol,
2.3 equiv.) was added portion wise over 1 h (each time iodine was added
the solution became orange and only when the solution became white
more iodine was added). After completion of the starting material (3 h), the
reaction mixture was diluted with DCM (100 mL) and filtered over Celite.
The filtered solution was washed with saturated aqueous sodium hydrogen
carbonate and then water. Organic phases were combined and dried with
MgSO4, filtered, and concentrated under reduced pressure to give a syrup
purified by CC eluted with CyHex-EtOAc 4:1, affording compound 6 as a
colourless oil in 77% yield (2,32 g). Physical and spectroscopic data are
fully in agreement with the assigned structure, that was previously reported
in the literature.[10]
Methyl
2,3,6-tri-O-benzyl-4-deoxy-α-D-xylo-hexopyranoside
(7).
Compound 6 (2.30 g, 4.95 mmol) was dissolved in DCM (70 mL) and
pyridine (0.9 mL, 11.39 mmol, 2.3 equiv.), and cooled to -10 ºC, under N2.
Trifluoromethanesulfonic anhydride (1.92 mL, 11.39 mmol, 2.3 equiv.) was
then added dropwise to the stirred solution, which was then warmed to 2
ºC and stirred for 2 h 30 min. The reaction was quenched by addition of
cool distilled water (100 mL), followed by extraction with DCM (2 x 100
mL). Organic phase was dried with MgSO4, filtered and evaporated under
reduced pressure, affording highly labile off-white powder composed by
Experimental Section
Chemistry. Starting materials and reagents were purchased from Sigma–
Aldrich, Fluka and Acros. The solvents were dried prior to use with 4 or 3
Å (methanol) molecular sieves. The spectroscopic and physical data of
these compounds are in agreement with those previously reported. TLC
was carried out on aluminium sheets (20 cm x 20 cm) coated with 0.2 mm
silica gel 60 F-254 (Merck) and detection was accomplished by spraying
the plates with a solution of H2SO4 in ethanol (10%) followed by heating at
120 °C. The compounds were purified by column chromatography (CC)
using silica gel 60G (0.040–0.063 mm, Merck) or silica gel 60G (0.015–
0.040 mm, Merck). Melting points were first obtained with a SMP3 Melting
Point Apparatus, Stuart Scientific, Bibby. Optical rotations were measured
methyl
2,3,6-tri-O-benzyl-4-deoxy-4-trifluoromethanesulfonyl-α-D-
glucopyranoside. The solid was dissolved in toluene (74 mL), and tetra-n-
butylammonium borohydride (3.76 g, 14.85 mmol, 3 equiv.) was added.
The reaction mixture was stirred at 85 ºC for 2 h, cooled to room
temperature and then poured into ice cold water (100 mL). After extraction
with DCM (2x50 mL), the organic phase was washed with saturated
aqueous sodium hydrogen carbonate (2x50 mL) and water (50 mL).
Organic phases were combined and dried with MgSO4, filtered, and
concentrated under reduced pressure. The residue was purified by CC
eluted with hex/EtOAc 10:1 to afford compound 7 as a colourless oil in
83% yield (1.84 g). Physical and spectroscopic data were in agreement
with those previously reported for this compound.[11]
with
a
Perkin–Elmer 343 polarimeter. Compounds structural
characterization was accessed by NMR and high-resolution mass
spectrometry (MS) analyses. Specific NMR assignements were
determined by multidimensional and decoupling experiments. H and 13
1
C
NMR spectra for final compounds are provided in Supplementary
Information (Figures S1 to S18). NMR spectra were recorded with a Bruker
Avance 400 spectrometer at 298 K operating at 100.62 MHz for 13C NMR
and at 400.13 MHz for 1H NMR. The solvents used were CDCl3 with 0.03%
TMS and CD3OD (Sigma–Aldrich). The chemical shifts are reported as δ
(ppm) and the coupling constants (J) are given in Hz. High resolution ESI
positive mode mass spectra were obtained on a QqTOF Impact IITM mass
spectrometer (Bruker Daltonics) operating in the high-resolution mode.
Dodecyl 4-deoxy-D-xylo-hexopyranoside (8a,b).
A
solution of
compound 7 (1.498 g, 3.34 mmol) in dodecan-1-ol (11.2 mL, 50 mmol, 15
equiv.), containing Amberlyst 15 beads (0.250 g) was stirred at 100 ºC for
4.5 h. The solution was diluted with DCM, the resin beads were filtered off,
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
and the solution was concentrated under reduced pressure. The residue
was taken up in methanol (15 mL) and, after addition of Pd/C 10% (50 mg)
and inertization of the vessel with N2, triethylsilane (1.8 mL, 21.26 mmol,
6.4 equiv.) was added dropwise. After 24 h, the catalyst was filtered off
using Celite, the solvent was evaporated under reduced pressure, and the
residue was purified by CC (Petrol. ether/EtOAC 1:1  EtOAc). The
anomeric mixture 8a,b (1.1:1 α/β) was obtained as a white solid, in 80%
methanol (0.1 mL per 0.100 mg of substrate) is added. The reaction
mixture is stirred for 2 h at room temperature. Neutralization with Amberlite
IR-120, filtration and evaporation of the solvent, afforded the deacetylated
compounds 1 and 11 in quantitative yield.
Dodecyl 2,3-di-O-acetyl-4,6-dideoxy-α-D-xylo-hexopyranoside (9).
Syrup. Rf (hex/EtOAc 5:1) = 0.50; 1H NMR (400.13 MHz, CDCl3, 25 ºC): δ
= 5.25 (ddd, 3J2,3 = 10 Hz, 3J3,4ax = 11 Hz, 3J3,4eq = 5 Hz, 1 H, 3-H), 4.97 (d,
3J1,2 = 3.4 Hz, 1 H, 1-H), 4.80 (dd, 1 H, 2-H), 4.05-3.95 (m, 1 H, 5-H), 3.65
(td, 3J1'a,1'b = 10 Hz, 3J1'a,2' = 7 Hz, 1 H, 1'a-H), 3.36 (td, 3J1'b,2' = 7 Hz, 1 H,
1'b-H), 2.18 (br dd, 3J3,4eq= 5 Hz, 3J4eq,5 = 1 Hz, 1 H, 4eq-H), 2.06 (s, 3 H, -
1
yield (o.89 g). Rf (EtOAc/Tol 3:1) = 0.20; H NMR (400.13 MHz, CD3OH,
25 ºC): δ = 4.81 (d, 3J1,2=3.6 Hz, 1 H, 1α-H), 4.19 (d, 3J1,2=7.9 Hz, 1 H, 1β-
3
H), 3.91-3.80 (m, 3 H, 3α-H, 5α-H and 1'aβ-H), 3.72 (td, J1'a,1'b= 9 Hz,
3J1'a,2'=7 Hz, 1 H, 1'aα-H), 3.65-3.48 (m, 7 H, 3β-H, 5β-H, 6α-H, 6β-H, 1'bβ-
H), 3.42 (td, 1 H, 1'bα-H), 3.32 (m, 1 H, 2α-H)*, 3.08 (t, 3J1,2=3J2,3=7.9 Hz,
1 H, 2β-H), 1.93 (br dd, 2 H, 3J4ax,4eq= 13 Hz, 3J4eq,5=3J3,4eq= 3 Hz, 4eqα-H,
4eqβ-H), 1.69-1.67 (m, 4 H, 2'α-H, 2'β-H), 1.42-1.25 (m, 38 H, 3'-H to 11'-
H α and β, 4axα-H, 4axβ-H), 0.92-0.88 (m, 6 H, 12'α-H, 12'β-H) ppm. 13C
NMR (100.62 MHz, CD3OD, 25 ºC): δ = 104.7 (C-1β), 100.7 (C-1α), 76.9
(C-2β), 75.6 (C-2α), 73.9, 72.3, 70.9, 70.0 (C-3 e C-4, α and β), 69.1 (C-
1'α), 68.9 (C-1'β), 65.7 (C-6α), 65.6 (C-6β), 36.6 (C-4α, C-4β), 33.2, 30.9,
30.9, 30.7, 30.6, 27.4, 27.2, 23.8 (C-2' to C-11' α and β), 14.6 (C-12' α and
β) ppm. *Signal under MeOH signal. HRMS: Calcd. [C18H36NaO5]
335.2455; Found 335.2451 (error 1.0 ppm).
OAc), 2.02 (s,
3 H, -OAc), 1.60-1.52 (m, 2 H, 2'-H), 1.41 (q,
3J3,4ax=3J4,5=3J4eq,4ax = 11 Hz, 1 H, 4ax-H), 1.35-1.21 (m, 18 H, 3'-H to 11'-
H), 1.18 (d, 3J5,6 = 6 Hz, 3 H, 6-H), 0.87 (t, 3J11',12' = 6 Hz, 3 H, 12'-H) ppm.
13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 170.5 (C=O, OAc), 170.3 (C=O,
OAc), 96.3 (C-1), 72.2 (C-2), 68.2 (C-3), 68.0 (C-1'), 63.0 (C-5), 38.2 (C-
4), 31.9, 29.7, 29.6, 29.4, 29.3, 26.1, 22.7 (C-2' to C-11'), 21.1 (CH3, OAc),
20.9 (CH3, OAc), 20.6 (C-6), 14.1 (C-12’) ppm.
Dodecyl 2,3-di-O-acetyl-4,6-di-deoxy-β-D-xylo-hexopyranoside (10).
Colourless oil; Rf (hex/EtOAc 5:1) = 0.39; 1H NMR (400.13 MHz, CD3OH,
25 ºC): δ = 4.96 (ddd, 3J2,3 = 10 Hz, 3J3,4ax = 10 Hz, 3J3,4eq = 5 Hz, 1 H, 3-
H), 4.85 (dd, 3J1,2 = 3J2,3 = 8 Hz, 1 H, 2-H), 4.35 (d, 3J1,2=8 Hz, 1 H, 1-H),
3.85 (td, 3J1'a,1'b = 10 Hz, 3J1'a,2' = 7 Hz, 1 H, 1'a-H), 3.68-3.58 (m, 1 H, 5-H),
3.45 (td, 1 H, 1'b-H), 2.12-2.06 (m, 1 H, 4eq-H), 1.71-1.42 (m, 5 H, 2'-H,
Dodecyl 4-deoxy-α-D-xylo-hexopyranoside (8a). An aliquote of the
anomeric mixture 8a,b was further purified by CC with CHCl3:EtOH 95:5,
to afford the pure alfa-anomer (8a) for characterization and biological
evaluation. Rf (CHCl3:EtOH 9:1) = 0.3; m.p.=79.6-80.7°C; [α]2퐷0= 71º (c1,
MeOH). 1H NMR (400.13 MHz, CD3OH, 25 ºC): δ = 4.80 (d, 3J1,2=3.6 Hz,
1 H, 1-H), 3.89-3.80 (m, 2 H, 3-H, 5-H), 3.71 (td, 3J1'a,1'b= 9 Hz, 3J1'a,2'=7 Hz,
1 H, 1'a-H), 3.52 (br d, 3J5,6=5 Hz, 2 H, 6a,b-H, 3.41 (td, 1 H, 1'b-H), 3.30
(1H, 2-H)*, 1.92 (ddd, 3J4ax,4eq = 12 Hz, 3J4eq,5 = 2, 3J3,4eq = 5 Hz, 1 H, 4eq-H),
1.71-1.55 (m, 2 H, 2'-H), 1.48-1.23 (m, 19 H, 3'-H to 11'-H, and 4ax-H),
0.92 (t, 3 H, 12'-H) ppm. 13C NMR (100.62 MHz, CD3OD, 25 ºC): δ = 100.7
(C-1), 75.5 (C-2), 73.8, 69.9 (C-3, C-5), 69.0 (C-1'), 65.7 (C-6), 36.5 (C-4),
33.1, 30.8, 30.7, 30.6, 30.5, 27.4, 23.7 (C-2' to C-11'), 14.5 (C-12') ppm.
*Signal partially under MeOH signal. HRMS: Calcd. [C18H36NaO5]
335.2455; Found 335.2444 (error 3.0 ppm).
3'-H, 4ax-H), 1.41-1.17 (m, 19 H, 4'-H to 11'-H and 6-H), 0.86 (t, 3J11',12'
=
7 Hz, 3 H, 12'-H) ppm. 13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 170.1
(C=O, OAc), 169.8 (C=O, OAc), 98.8 (C-1), 72.6 (C-2), 71.2 (C-3), 69.8
(C-1'), 67.7 (C-5), 37.9 (C-4), 31.9, 29.7, 29.6, 29.5, 29.4, 25.9, 22.7 (C-2'
to C-11'), 21.0 (CH3, OAc), 20.9 (CH3, OAc), 20.7 (C-6), 14.1 (C-12') ppm.
Dodecyl 4,6-dideoxy-α-D-xylo-hexopyranoside (1). Obtained from
compound 9 (0.099g, 0.25 mmol), as a white solid in 96% yield (0.076 g).
Rf (tol/EtOAc 2:3)=0.31; M.p.=34.3-36.0 °C; [α]2퐷0= +103 º (c1, CH2Cl2); 1H
NMR (400.13 MHz, CD3OH, 25 ºC): δ = 4.70 (d, 3J1,2 = 3.4 Hz, 1H, 1-H),
3.90 (quint. d, 3J5,6=6 Hz, 3J4eq,5=2 Hz, 1H, 5-H), 3.77 (qd, 3J2,3 = 3J3,4x = 10
3
Hz, 3J3,4eq = 5 Hz, 1 H, 3-H), 3.62 (td, J1'a,1'b = 10 Hz, 3J1'a,2 ' = 7 Hz, 1 H,
1'a-H), 3.40 (td, 3J1'b,2' = 6 Hz, 3J1'b,2' = 7 Hz, 1 H, 1'b-H), 3.24 (dd, 3J2,3 = 9
Hz, 1 H, 2-H), 1.91 (ddd, 3J4ax,4eq = 12 Hz, 1 H, 4eq-H), 1.65-1.51 (m, 2 H,
2'-H), 1.40-1.18 (m, 19 H, 3'-H to 11'-H and 4ax-H), 1.13 (d, 3J5,6 = 6 Hz, 3
H, 6-H), 0.87 (br t, 3J11',12' = 6 Hz, 3 H, 12'-H) ppm. 13C NMR (100.62 MHz,
CD3OD, 25 ºC): δ = 100.8 (C-1), 75.5 (C-2), 69.1, 68.9 (C-1' and C-3), 65.2
(C-5), 42.3 (C-4), 33.1, 30.8, 30.7, 30.6, 30.5, 27.4, 23.8 (C-2' to C-11'),
21.2 (C-6), 14.5 (C-12’) ppm. HRMS: Calcd. [C18H36NaO4] 339.2506;
Found 339.2509 (error -1.1 ppm)
Dodecyl 4,6-dideoxy-α/β-D-xylo-hexopyranoside (1, 11). The anomeric
mixture 8a,b (0.3176 g, 0.955 mmol) was dissolved in DCM (10 mL) and
pyridine (0.12 mL, 1.43 mmol, 1.5 equiv.), and cooled to -10 ºC, under N2.
Trifluoromethanesulfonic anhydride (0.24 mL, 1.43 mmol, 1.5 equiv.) was
added dropwise to the stirring solution, which was then warmed to 2ºC and
stirred for 1 h. The reaction was quenched by addition of 20 mL of cool
distilled water, followed by extraction with DCM (2 x 20 mL). The organic
phase was dried with MgSO4, filtered and evaporated under reduced
pressure at 25 ºC, affording a syrup. This intermediate triflate was
dissolved in THF (8.3 mL), and a 2 M LiAlH4 solution in THF (1.67 mL,
3.34 mmol, 3.5 equiv.) was added dropwise at 0 ºC. After stirring 1 h at
room temperature, the reaction was again cooled to 0 ºC and the
aluminium salts were removed by slow addition of water (0.3 mL), aqueous
NaOH 15% (0.9 mL) and water (0.9 mL) gave a mixture kept under stirring
for 15 min at room temperature. Addition of MgSO4 resulted in a
suspension, and after filtration of the solids, the solution was concentrated
under reduced pressure to give a syrup composed by an inseparable
anomeric mixture of dodecyl 4,6-dideoxy-D-xylo-hexopyranoside, which
was dissolved in pyridine (4 mL), and Ac2O (2 mL) followed by a spatula
tip of DMAP. The reaction was stirred at room temperature overnight. The
fully acetylated α and β glycosides could be distinguished in the TLC plate
(hex/EtOAc 5:1). After co-evaporation of pyridine with toluene, the
anomers were purified by column chromatography (hex/EtOAc 25:1) to
afford the dodecyl 2,3-di-O-acetyl-4,6-dideoxy-α-D-xylo-hexopyranoside
(9, 116 mg, 30% yield) and dodecyl 2,3-di-O-acetyl-4,6-dideoxy-β-D-xylo-
hexopyranoside (10, 42 mg, 11% yield). The acetylated compound (9 or
10) is dissolved in methanol (100mg/mL), and a 1M solution of NaOMe in
Dodecyl 4,6-dideoxy-β-D-xylo-hexopyranoside (11). Obtained from
compound 10 (0.030g, 0.075 mmol), as a white solid in 94% yield (0.022
g). Rf (tol/EtOAc 2:3) = 0.31; M.p.=48.2-50.7 °C; [α]2퐷0 = -30 º (c0.6,
CH2Cl2); 1H NMR (400.13 MHz, CD3OH, 25 ºC): δ = 4.12 (d, 3J1,2 = 7.9 Hz,
1 H, 1-H), 3.78 (td, 3J1'a,1'b = 10 Hz, 3J1'a,2' = 7 Hz, H 1, 1'a-H), 3.60-3.44 (m,
3 H, 1'b-H, 3-H and 5-H), 3.01 (t, 3J1,2 = 3J2,3 = 8 Hz, 1 H, 2-H), 1.89 (ddd,
3J4ax,4eq = 13 Hz, 3J3,4eq = 2 Hz, 1 H, H-4eq), 1.58 (quint, 3J1'a,2' = 3J2'a,3' = 7Hz,
2 H, H-2'), 1.39-1.21 18 (m, 19 H, 3'-H to 11'-H and 4ax-H), 1.13 (d, 3J5,6
=
6 Hz, 3 H, H-6), 0.87 (br t, 3J11',12' = 6 Hz, 3 H, 12'-H) ppm. 13C NMR (100.62
MHz, CD3OD, 25 ºC): δ = 104.6 (C-1), 76.8 (C-2), 72.2 (C-3), 70-9 (C-1'),
69.1 (C-5), 42.1 (C-4), 33.1, 30.9, 30.8, 30.6, 30.5, 27.1, 23.8 (C-2' to C-
11'), 21.3 (C-6), 14.5 (C-12') ppm. HRMS: Calcd. [C18H36NaO4] 339.2506;
Exp. 339.2495 (error 3.3 ppm).
1,2:5,6-Di-O-isopropylidene-3-deoxy-α-D-ribo-hexofuranose
(13).
Triflic anhydride (1.3 mL, 7.68 mmol, 2 equiv.) was added dropwise to a
stirring solution of 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose (1.00g,
3.84 mmol) in DCM (30 mL) and pyridine (0.62 mL, 7.68 mmol, 2 equiv.),
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
at -10 ºC under N2. The reaction was stirred for 15 min, after which
complete conversion of the starting material into the triflate derivative had
occurred. The reaction was poured into 50 mL of ice cold water and the
organic phase was separated. The aqueous phase was further extracted
with DCM (2x50 mL). Organic phases were combined, dried with MgSO4
and evaporated under reduced pressure, affording 1,2:5,6-di-O-
isopropylidene-3-O-triflyl-α-D-ribo-hexofuranose as a colourless oil in 82%
yield. Rf (hex/EtOAC 2:1) = 0.78, 1H RMN (400.13 MHz, CDCl3, 25 ºC): δ
= 5.98 (d, 3J1,2 = 5 Hz, 1 H, 1-H), 5.36 (br s, 1 H, 3-H), 4.76 (d, 1 H, 2-H),
4.22-4.13 (m, 3 H, 4-H, 5-H, 6a-H), 3.97 (dd, 3J6a,6b = 9 Hz, 3J5,6b = 3 Hz, 1
H, 6b-H), 1.52 (s, 3 H, -CH3 isoprop.), 1.42 (s, 3 H, -CH3 isoprop.), 1.34 (s,
3 H, -CH3 isoprop.), 1.33 (s, 3 H, -CH3 isoprop.) ppm. 13C RMN (100.62
MHz, CDCl3, 25 ºC): δ = 113.1 (Cq isoprop.), 109.8 (Cq isoprop.), 105.0
(C-1), 88.1 (C-2),83.2 (C-3), 79.9 (C-4), 71.7 (C-5), 67.6 (C-6), 26.8, 26.5,
26.2, 24.8 (-CH3 isoprop.) ppm.
1,2:5,6-Di-O-isopropylidene-3-O-triflyl-α-D-ribo-hexofuranose (1.85 g,
4.74 mmol) was dissolved in dried toluene (100 mL) and n-Bu4NBH4 (2.4
g, 9.47 mmol, 2 equiv.) was added in one portion. The reaction mixture
was refluxed under N2 for 4 h and quenched by pouring the solution into
ice cold water (40 mL). The organic phase was extracted with DCM (2 x
50 mL) and washed with a saturated sodium bicarbonate (50 mL) and
water (50 mL). The organic phase was dried with MgSO4 and evaporated
under reduced pressure. The resulting residue was purified by column
chromatography, eluted with hex/EtOAc 9:1, affording compound 13 as a
colourless oil in 54% yield (0.624 g). Rf (Hex/EtOAC 4:1) = 0.31; [α]2퐷0= -5
º (c1, CHCl3); 1H RMN (400.13 MHz, CDCl3, 25 ºC): δ = 5.82 (d, 3J1,2 = 3
Hz, 1 H, 1-H), 5.36 (br s, 1 H, 3-H), 4.76 (br t, 3J2,3b=4, 1 H, 2-H), 4.19-4.09
(m, 3 H, 4-H, 5-H, 6a-H), 3.82 (dd, 3J6a,6b =8 Hz, 3J5,6b = 5 Hz, 1 H, 6b-H),
2.19 (dd, 3J3a,3b = 14 Hz, 3J3a,4 = 3 Hz, 1 H, 3a.H), 1.77 (ddd, 3J3b,4 = 5 Hz,
1 H, 3b-H), 1.52 (s, 3 H, -CH3 isoprop.), 1.43 (s, 3 H, -CH3 isoprop.), 1.36
(s, 3 H, -CH3 isoprop.), 1.32 (s, 3 H, -CH3 isoprop.) ppm. 13C RMN (100.62
MHz, CDCl3, 25 ºC): δ = 111.3 (Cq isoprop.), 109.6 (Cq isoprop.), 105.6
(C-1), 80.4 (C-2), 78.6 (C-4, C-5), 67.2 (C-6), 35.2 (C-2) 26.8, 26.5, 26.2,
24.8 (-CH3 isoprop.) ppm. HRMS: Calcd. [C12H21O5] 245.1384; Found
245.1392 (error 3.3 ppm).
6ª-H), 3.65 (br td, 3J1'a,1'b = 9 Hz, 3J1'a,2' = 7 Hz, 1 H, 1'a-H), 3.55 (dd, 3J5,6b
= 6 Hz, 1 H, 6b-H), 3.50-3.43 (m, 1 H, 5-H), 3.36 (td, J1'b,2' = 7 Hz, 1 H,
3
1'b-H), 2.12-2.03 (m, 1 H, 3a-H), 1.97 (dd, 3J3b,4 = 7 Hz, 3J3a,3b = 13 Hz, 1
H, 3b-H), 1.58-1.49 (m, 2 H, 2'-H), 1.39-1.22 (m, 18 H, 3'-H to 11'-H), 0.90
(t, 3J11',12' = 6Hz, 3 H, 12'-H) ppm. 1C NMR (100.62 MHz, CD3OD, 25 ºC):
δ =109.7 (C-1), 80.7 (C-4), 76.9 (C-5), 76.5 (C-2), 68.4 (C-1'), 65.2 (C-6),
36.0 (C-3), 33.1, 30.8, 30.7, 30.6, 30.5, 27.3, 23.7 (C-2’ to C-11'), 14.5 (C-
12') ppm. HRMS: Calcd. [C18H36NaO4] 335.2455; Found 335.2454 (error
0.3 ppm).
Dodecyl 3-deoxy-α-D-ribo-hexopyranoside (16). Rf (DCM/MeOH 12:1)
= 0.31; m.p.=94.0-95.0°C; [α]2퐷0= +83 º (c0.3, CH2Cl2); 1H NMR (400.13
MHz, CD3OD, 25 ºC): δ = 4.64 (d, 3J1,2=3 Hz, 1 H, 1-H), 4.59 (s, 1 H, OH),
3.80-3.68 (m, 2 H, 1'a-H, 6a-H), 3.64-3.54 (m, 2 H, 2-H, 6b-H), 3.50-3.39
(m, 3 H, 1'b-H, 4-H and 5-H), 2.01 (td, 3J2,3eq = 3J3eq,4 = 4 Hz, 3J3e,3ax = 11
Hz, 1 H, 3eq-H), 1.76 (q, 3J2,3ax = 3J3ax,4 = 3J3e,3ax = 11 Hz, 1 H, 3ax-H), 1.67-
1.54 (m, 2 H, 2'-H), 1.45-1.20 (m, 18 H, 3'-H to 11'-H), 0.87 (t, 3 H, 3J11',12'
1
= 6 Hz, 1 H, 12'-H) ppm. C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 98.9
(C-1), 74.4 (C-4), 68.8 (C-1'), 68.5 (C-2), 66.2 (C-5), 62.7 (C-6), 36.9 (C-
3), 33.1, 30.8, 30.7, 30.5, 27.4, 23.8 (C-2' to C-11'), 14.5 (C-12') ppm.
HRMS: Calcd. [C18H36NaO5] 355.2455; Found 355.2449 (error 1.6 ppm).
Dodecyl 2,3-dideoxy-α,β-D-erythro-hex-2-enopyranosides (18a,b). To
a
solution of 3,4,6-tri-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-
enitol (2.0 g, 7.35 mmol) in dichloromethane (60 mL), dodecan-1-ol (1.81
mL, 8.08 mmol, 1.1 equiv.) and BF3•Et2O (0.05 mL, 0.37 mmol, 0.05
equiv.) were added. After 2 h at room temperature, the reaction, which had
turned blue, was washed twice with NaHCO3 (2 x 100 mL) and with brine
(100 mL). The organic phase was dried with anhydrous MgSO4, which was
filtered off, and concentrated under reduced pressure. The resulting
residue was dissolved in methanol (25 mL) and, after addition of a 1M
solution of NaOMe in MeOH (0.6 mL), the reaction stirred for 1.5 h at room
temperature. Neutralization with Amberlite IR-120, filtration and
evaporation of the solvent gave a residue that was purified by CC eluted
with hex/EtOAc 2:1, affording compound 18a as a white solid in 73% yield
(1.69 g), along with the beta anomer 18b as a colourless oil in 11% yield
(0.025 g).
3-Deoxy-D-ribo-hexopyranose (14). Compound 13 (1.00 g, 4.09 mmol),
was dissolved in aqueous trifluoroacetic acid 80% (7 mL) and stirred at 40
ºC for 2 h. Co-evaporation of the acid with toluene gave 14 as a colourless
oil in quantitative yield (α/β 0.8:1) (0.67 g). Rf (DCM/EtOH 9:1) = 0.15; 1H
Dodecyl 2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (18a). Rf
(hex/EtOAc 1:1) = 0.45; m.p.=68.6-69.6 °C; [α]2퐷0= +45 º (c0.3, CH2Cl2); 1H
NMR (400.13 MHz, CDCl3, 25 ºC): δ = 5.87 (br d, 3J2,3 = 10 Hz, 1 H, 3-H),
3
RMN (400.13 MHz, CD3OD, 25 ºC): δ = 4.95 (d, J1,2=3 Hz, 1 H, 1α-H),
4.33 (d, 3J1,2=8 Hz, 1 H, 1β-H), 3.77-3.66 (m, 1 H, 6aβ-H), 3.59-3.50 (m, 4
H, 2α-H, 6bβ-H, 6aα-H, 5β-H), 3.49-3.36 (m, 3 H, 4α-H, 6bα-H, 4β-H),
5.69 (td, 3J1,2 = 2 Hz, 1 H, 2-H), 4.93 (br s, 1 H, 1-H), 3.99 (dd, 1H, 3J3,4
1 Hz, 3J4,5 = 9 Hz, 1 H, 4-H), 3.83-3.74 (m, 2 H, 6a-H and 1'a-H), 3.70-3.57
=
3.27-3.13 (m, 2 H, 5α-H, 2β-H), 2.20 (td, 3J2,3e = 3J3e,4 = 5 Hz, 3J3a,3e = 12
3
3
(m, 2 H, 5-H and 6b-H), 3.44 (td, J1'a,1'b = 10 Hz, J1'b,2' = 6 Hz, 1 H, 1'b-
H),1.60-1.51 (m, 2 H, 2'-H), 1.39-1.20 (m, 18 H, 3'-H to 11'-H), 0.88 (t,
3J11',12' = 6 Hz, 3 H, 12'-H) ppm.13C NMR (100.62 MHz, CDCl3, 25 ºC): δ =
134.6 (C-3), 127.3 (C-2), 95.5 (C-1), 73.6 (C-5), 69.5 (C-1'), 64.2 (C-4),
62.7 (C-6), 33.1, 30.9, 30.8, 30.6, 30.5, 27.4, 23.8 (C-2' to C-11'), 14.5 (C-
12') ppm. HRMS: Calcd. [C18H34NaO4] 337.2349; Found 337.2348 (error
0.5 ppm).
3
Hz, 1 H, 3eqβ-H), 1.99-1.92 (m, 1 H, 3eqα-H), 1.72 (q, J2,3ax
= =
3J3ax,4
3J3ax,3e = 12 Hz, 1 H, 3axβ-H), 1.39 (q, 1H, 3J2,3ax = J3ax,4 = J3ax,3e=12 Hz, 1
H, 3axα-H) ppm. 13C RMN (100.62 MHz, CD3OD, 25 ºC): δ =100.1 (C-1β),
92.6 (C-1α), 81.7 (C-5α), 80.7, 76.8 (C-4α, C-4β), 73.7 (C-5β), 70.4 (C-2β),
66.2 (C-2α), 65.1 (C-6α), 62.8 (C-6β), 40.5 (C-3β), 36.1 (C-3α) ppm.
HRMS: Calcd. [C6H12NaO5] 187.0577; Found 187.0574 (error -1.6 ppm).
Fischer glycosylation procedure. Compound 14 (0.050g, 0.305 mmol)
and Amberlyst 15 (50mg/300mg substrate) were dissolved in dodecan-1-
ol (0.851 mL, 0.457 mmol, 15 equiv.) and the solution was stirred for 5 h
at 100 ºC. Reaction products were isolated by CC eluted with a gradient
from dichloromethane to dichlotomethane/ethanol 10:1. Compound 15
was isolated in 28% yield, as a colourless oil (28.4 mg), while compound
16 was isolated in 8% yield, as a white solid (8.1 mg). Both beta anomers
were detected in the TLC as traces and were not isolated.
Dodecyl 2,3-dideoxy-β-D-erythro-hex-2-enopyranoside (18b). Rf
(hex/EtOAc 1:1) = 0.33; [α]퐷20= +8 º (c1, MeOH); 1H NMR (400.13 MHz,
CDCl3, 25 ºC): δ = 6.02 (br d, 3J2,3 = 10 Hz, 1 H, 3-H), 5.78 (br d, 1 H, 2-
H), 5.14 (br s, 1 H, 1-H), 4.20 (br d, 3J4,5 = 5 Hz, 1 H, 4-H), 3.90-3.75 (m, 3
H, 6a-H, 6b-H and 1'a-H), 3.68 (ddd, 3J5,6a = 2 Hz, 3J5,6b = 6 Hz, 1 H, H-5),
3.51 (td, 3J1'a,1'b = 9 Hz, 3J1'b,2 = 7 Hz, 1 H, 1'b-H), 2.88 (br s, 2 H, OH), 1.64-
1.54 (m, 2 H, 2'-H), 1.38-1.18 (m, 18 H, 3'-H to 11'-H), 0.88 (t, 3J11',12' = 6
Hz, 3 H, 12'-H) ppm.13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 132.0 (C-
3), 128.1 (C-2), 96.3 (C-1), 78.2 (C-5), 68.7 (C-1'), 63.3, 63.2 (C-4 and C6),
31.9, 29.7, 29.6, 29.5, 29.4, 26.0, 22.7 (C-2' to C-11'), 14.1 (C-12') ppm.
HRMS: Calcd. [C18H34NaO4] 337.2349; Found 337.2353 (error -1.1 ppm).
Dodecyl 3-deoxy-α-D-ribo-hexofuranoside (15). Rf (DCM/MeOH
12:1)=0.29; [α]2퐷0= -50 º (c0.1, CH2Cl2); 1H NMR (400.13 MHz, CD3OD, 25
ºC): δ = 4.83 (s, 1 H, H-1), 4.22 (q, 3J3a,4 = 3J3b,4 = 3J4,5 = 7 Hz, 1 H, H-4),
4.13 (d, 3J2,3a = 4 Hz, 1 H, 2-H), 3.73 (dd, 3J5,6a = 3Hz, 3J6a,6b = 12 Hz, 1 H,
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
Dodecyl 2,3-anhydro-α-D-allo-hexopyranoside (19). Sodium hydrogen
carbonate (0.033g, 0.40 mmol, 2 equiv.) and m-CPBA (0.069g, 0.40 mmol,
2 equiv.) were added to a stirring solution of 2,3-unsaturated compound
18a (0.063g, 0.20 mmol) in DCM (2 mL). The solution was stirred
vigorously at room temperature for 3 days. The reaction mixture was
diluted with DCM (10 mL), washed with saturated aqueous NaHCO3 (2x25
mL), and saturated aqueous Na2S2O3 (2x25 mL). The organic phase was
dried with MgSO4, filtered and evaporated, to give a residue, which was
purified by CC eluted with cyHex/EtOAc 1:1. Compound 19 was isolated
in 74% yield (0.043 g), based on reacted starting material, recovered in
12% yield. Rf (hex./EtOAc 1:2)=0.23; m.p.= 91.2-94.0°C; [α]2퐷0= +40 º (c0.1,
CH2Cl2); 1H NMR (400.13 MHz, CD3OD, 25 ºC): δ = 4.96 (d, 3J1,2 = 3 Hz,
1 H, 1-H), 4.60 (br s, 1 H, OH), 3.83-3.68 (m, 3 H, 6a-H, 1'a-H, 5-H), 3.63-
3.56 (m, 2 H, 6b-H, 4-H), 3.50-3.43 (m, 2 H, 1'b-H, 2-H), 3.35 (br dd, 3J2,3
= 4.0 Hz, 3J3,4 = 1.5 Hz, 1 H, 3-H), 1.63-1.54 (m, 2 H, 2'-H), 1.40-1.22 (m,
Dodecyl
4,6-di-O-benzyl-2,3-dideoxy-α-D-erythro-hex-2-
enopyranoside (22a). Rf (hex/EtOAc 8:1)= 0.5; [α]2퐷0= +58 º (c1, CH2Cl2);
1H NMR (400.13 MHz, CDCl3, 25 ºC): δ = 7.41-7.24 (m, 10 H, CH2Ph),
6.09 (d, 3J2,3 = 10 Hz, 1 H, 3-H), 5.80 (br d, 1 H, 2-H), 5.04 (br s, 1 H, 1-H),
4.72-4.44 (m, 4 H, CH2PH), 4.20 (d, 3J4,5=9Hz, 1 H, 4-H), 4.02-3.96 (m, 1
H, 5-H), 3.83-3.69 (m, 3 H, 6-H, 1'a-H), 3.50 (td, 3J1'a,1'b = 10 Hz, 3J1'a,2’ = 7
Hz, 1 H, 1'b-H), 1.68-1.54 (m, 2 H, 2'-H), 1.40-1.20 (m, 18 H, 3'-H to 11'-
H), 0.91 (t, 3J11',12'=7 Hz, 3 H, 12'-H) ppm. 13C NMR (100.62 MHz, CDCl3,
25 ºC): δ = 138.2, 138.1 (Cq, Ph), 130.5 (C-3), 128.4, 128.3, 127.9, 127.8,
127.7, 127.6 (CH, Ph), 126.7 (C-2), 94.6 (C-1), 73.3, 71.0 (CH2Ph), 70.3
(C-4), 69.1 (C-5), 68.9 (C-6), 68.7 (C-1'), 31.9, 29.8, 29.7, 29.6, 29.4, 29.3,
26.2, 22.7 (C-2' to C11'), 14.1 (C-12') ppm. HRMS: Calcd. [C32H46NaO4]
517.3291; Found 517.3288 (error -0.4 ppm).
Dodecyl
4,6-di-O-benzyl-2,3-dideoxy-β-D-erythro-hex-2-
3
1
18 H, 3'-H to 11'-H), 0.87 (t, J11',12'=7 Hz, 3 H, 12'-H) ppm. The coupling
enopyranoside (22b). Rf (hex./EtOAc 8:1)=0.49; H NMR (400.13 MHz,
CDCl3, 25 ºC): δ = δ 7.39-7.20 (m, 10 H, CH2Ph), 6.06 (d, 3J2,3 = 10 Hz, 1
H, 3-H), 5.77 (br td, 3J1,2 = 2 Hz, 1 H, 2-H), 5.01 (br s, 1 H, H-1), 4.67-4.42
(m, 4 H, CH2PH), 4.17 (d, 3J4,5 = 9Hz, 1 H, 4-H), 3.98-3.93 (m, 1 H, 5-H),
3.83-3.66 (m, 3 H, 6-H, 1'a-H), 3.47 (td, 3J1'a,1'b = 9 Hz, 3J1'a,2' = 6 Hz, 1 H,
1'b-H), 1.61-1.54 (m, 2 H, 2'-H), 1.35-1.20 (m, 18 H, 3'-H to 11'-H), 0.88 (t,
3J11',12' = 7 Hz, 3 H, 12'-H) ppm. 13C NMR (100.62 MHz, CDCl3, 25 ºC): δ =
138.3, 137.9 (Cq, Ph), 129.2 (C-3), 128.4, 128.3, 127.7, 127.6 (CH, Ph),
126.7 (C-2), 96.0 (C-1), 73.3, 71.0 (CH2Ph), 75.3 (C-4), 69.9 (C-5), 69.6
(C-6), 68.4 (C-1'), 29.8, 29.7, 29.6, 29.5, 29.3, 26.1, 22.7 (C-2' to C11'),
14.1 (C-12') ppm. HRMS: Calcd. [C32H46NaO4] 517.3291; Found 517.3290
(error -0.2 ppm).
constants are in agreement with those registered for an acetylated
analogue in the literature[12] 1C NMR (100.62 MHz, CD3OD, 25 ºC): δ =
94.9 (C-1), 70. 9 (C-4), 69.2 (C-1'), 66.4 (C-5), 62.4 (C-6), 56.2 (C-2),
55.2(C-3), 33.1, 30.8, 30.7, 30.6, 30.5, 27.3, 23.8 (C-2' to C-11'), 14.5 (C-
12') ppm. HRMS: Calcd. [C18H34NaO5] 353.2298; Found 353.2308 (error -
2.7 ppm).
Dodecyl 3-deoxy-α-D-ribo-hexopyranoside (16) and dodecyl 2-deoxy-
α-D-ribo-hexopyranoside (20). To a solution of epoxide 19 (0.080g, 0.242
mmol) in THF (2 mL), a 2M solution of LiAlH4 in THF (0.24 mL, 0.484 mmol,
2 equiv.) was added dropwise, at 0 ºC. After stirring for 24 h at room
temperature, the reaction was cooled to 0 ºC and the aluminium salts were
removed by addition of water (0.2 mL), then aqueous NaOH 15 % (0.6
mL), then water (0.6 mL), and stirring for 15 min at room temperature.
MgSO4 was added to the resulting suspension and, after filtration of the
solids, the solution was concentrated under reduced pressure to give a
syrup, purified by CC eluted with hex/EtOAc 1:3, to give both 3-deoxy
glycoside and 16 and 2-deoxy glycoside 20 in 20% yield (0.0161 g) and
33% yield (0.0266 g), respectively, both as white solids.
Dodecyl 2,3-dideoxy-α-D-erythro-pyranoside (23). To a solution of
compound 22a (0.050g, 0.101 mmol) in MeOH (5 mL) and EtOAc (1 mL),
was added a suspension of 10% Pd/C (0.200g, wet) in MeOH (2 mL).
Under N2, triethylsilane was added dropwise (0.7 mL), leading to a visible
evolution of H2, and the solution was stirred overnight. After filtration of the
catalyst through Celite, and evaporation of the solvent, title compound was
obtained as a colourless oil in 51% yield (16.3 mg). Rf (Petrol. ether/EtOAC
1:1)=0.5; [α]2퐷0= +86 º (c0.1, CH2Cl2); 1H NMR (400.13 MHz, CDCl3, 25
ºC): δ = 4.72 (d, J1,2=3 Hz, 1 H, 1-H), 3.75 (dd, J5,6a = 2 Hz, 3J6a,6b = 11
Hz, 1 H, 6a-H), 3.67 (td, 3J1'a,1'b = 10 Hz, 3J1'a,2' = 7 Hz, 1 H, 1'a-H), 3.62 (dd,
3J5,6b = 5 Hz, 1 H, 6b-H), 3.47 (ddd, 3J4,5 = 9 Hz, 1 H, H-5), 3.44-3.37 (m, 1
H, 4-H), 3.34 (td, 1 H, 1'b-H), 1.83-1.65 (m, 4 H, 2-H and 3-H), 1.60-1.51
(m, 2 H, 2'-H), 1.42-1.20 (m, 18 H, 3'-H to 11'-H), 0.87 (t, 3J11'12'=7 Hz, 3 H,
H-12') ppm. 13C NMR (CDCl3) δ 95.3 (C-1), 73.3 (C-5), 66 (C-1'), 65.1 (C-
4), 61.1 (C-6), 31.1, 28.8, 28.6, 28.5 (C-2' to C-11'), 28.4, 21.8 (C3 and
C4), 12.5 (C-12') ppm. HRMS: Calcd. [C18H36NaO4] 339.2506; Found
339.2503 (error 0.7 ppm).
3
3
Dodecyl 3-deoxy-α-D-ribo-hexopyranoside (16). White solid; Rf
(hex./EtOAc 1:4)=0.35; Spectroscopic characterization is in full agreement
with the product obtained by Fischer glycosylation (above).
Dodecyl 2-deoxy-α-D-ribo-hexopyranoside (20). Rf (hex./EtOAc
1:4)=0.54; m.p.=51.6-52.8°C; [α]2퐷0 = +13 º (c0.5, CH2Cl2); 1H NMR
(400.13 MHz, CD3OD, 25 ºC): δ = 4.87 (1 H, 1-H, under MeOH signal),
4.60 (s, 1 H, OH), 3.91 (br d, 3J2,3=3 Hz, 1 H, 3-H), 3.85-3.6 (m, 4 H, 1'a-
3
H, 5-H, 6-H), 3.44 (dd, 3J3,4 = 2 Hz, 3J4,5 = 10 Hz, 1 H, 4-H), 3.36 (td, J1'a,1'b
= 10 Hz, 3J1'b,2' = 6 Hz, 1 H, 1'b-H), 2.02 (ddd, 3J1,2eq = 1 Hz, 3J2eq,3 = 3Hz,
3J2ax,2eq = 14 Hz, 1 H, 2eq-H), 1.89 (td, 3J2ax,3 = 3J1,2 = 3 Hz, 2ax-H), 1.66-
1.50 (m, 2 H, 2'-H), 1.40.20 (m, 18 H, 3'-H to 11'-H), 0.87 (t, 3J11',12' = 7 Hz,
Methyl 2,6-di-O-pivaloyl-α-D-glucopyranoside (24). To a solution of
methyl α-D-glucopyranoside (2,02 g, 10.4 mmol) in pyridine (20 mL), a
solution of pivaloyl chloride (2,2 equiv., 22,8 mmol, 2.8 mL) in DCM (4 mL)
was added dropwise, at -78 ºC. After stirring at -10 ºC for 2h, the reaction
was diluted with DCM (100 mL), washed with a 2M HCl solution until the
odour of pyridine was no longer detected. The organic phase then washed
with water, dried with MgSO4, filtered and evaporated. The resulting
residue was purified by CC eluted with petrol. ether/ EtOAc 5:1. Compound
24 was obtained as a white solid in 65% (2.44 g) yield. Physical and
spectroscopic data were in agreement with data reported in the
literature.[13]
1
1 H, 12'-H) ppm. C NMR (100.62 MHz, CD3OD, 25 ºC): δ = 98.3 (C-1),
70.0 (C-4), 69.0 (C-3), 68-9 (C-1'), 68.5 (C-5), 63.0 (C-6), 36.2 (C-2), 33.1,
30.8, 30.7, 30.6, 30.5, 27.4, 23.8 (C-2' to C-11'), 14.5 (C-12') ppm. HRMS:
Calcd. [C18H36NaO5] 335.2455; Found 335.2450 (error 1.3 ppm).
Dodecyl
4,6-di-O-benzyl-2,3-dideoxy-D-erythro-hex-2-
enopyranosides (22a,b). To a solution of 3,4,6-tri-O-benzyl-1,5-anhydro-
2-deoxy-D-arabino-hex-1-enitol (0.500 g, 1.2 mmol) in dichloroethane (5
mL), dodecan-1-ol (0.559g, 3 mmol, 2.5 equiv.) and zeolyte HY (0.192g,
pre-activated to 140 ºC) were added. The reaction was heated to 100 ºC
under microwave irradiation (200 W) in a closed vessel microwave reactor
for 30 min. The solution was then diluted in dichloroethane, filtered and
concentrated. The residue was purified by CC eluted with Hex/EtOAc 25:1,
affording compounds 22a and 22b in 29% (0.172 g) and 14% yield (0.083
g), respectively, both as colourless oils.
Methyl
2,6-di-O-pivaloyl-3,4-dideoxy-α-D-erythro-hexopyranoside
(25) and methyl 4-deoxy-2,6-di-O-pivaloyl-α-D-xylo-hexopyranoside
(26). Compound 24 (1 g, 2.75 mmol) was dissolved in DCM (30 mL) and
pyridine (0.89 mL, 11.0 mmol, 4 equiv.), and cooled to -10 ºC, under N2.
Trifluoromethanesulfonic anhydride (1.86 mL, 11.0 mmol, 4 equiv.) was
then added dropwise to the stirring solution, which was then warmed to 2
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
ºC and stirred for 2h30. The reaction was quenched by addition of 100 mL
of cool distilled water, followed by extraction with DCM (2 x 100 mL).
Organic phase was dried with MgSO4, filtered and evaporated under
reduced pressure, affording highly labile colourless syrup composed of
Dodecyl
3,4-dideoxy-β-D-erythro-hexopyranoside
(27b).
Rf
(CyHex/EtOAc 1:3)0.64; [α]퐷20= -22 º (c0.2, CH2Cl2); 1H NMR (100.62 MHz,
CDCl3, 25 ºC): δ = 4.21 (d, 3J1,2 = 8 Hz, 1 H, 1-H), 3.90 (td, 3J1'a,1'b= 10 Hz,
3J1'a,2' = 7 Hz, 1 H, 1'a-H), 3.66-3.56 (m, 3 H, 5-H and 6-H), 3.51 (td, 1 H,
1'b-H), 3.43-3.35 (m, 1 H, 2-H), 2.14-2.08 (m, 1 H, 3ax-H), 1.97 (br s, 2 H,
OH), 1.66-1.54 (m, 3 H, 2'-H and 4ax-H), 1.52-1.42 (m, 2, 3eq-H and 4eq-
methyl
2,6-di-O-pivaloyl-3,4-di-O-trifluoromethanesulfonyl-α-D-gluco-
pyranoside. The syrup was dissolved in toluene (32 mL), tetra-n-
butylammonium borohydride (4.180 g, 16.2 mmol, 5.9 equiv.) was added,
and the reaction mixture was stirred at 85 ºC overnight, cooled to room
temperature and poured into ice cold water (100 mL). After extraction with
DCM (2x50 mL), the organic phase was washed with saturated aqueous
sodium hydrogen carbonate (2x50 mL) and water (50 mL). The organic
phase was dried with MgSO4, filtered, and concentrated under reduced
pressure to give a syrup that was purified by CC eluted with Hex/EtOAc
10:1, to afford compound 27a as a colourless oil in 29% yield (0.263 g)
and compound 27b also as a colourless oil in 33% yield (0.314 mg).
3
H), 1.35-1.15 (m, 18 H, 3'-H to 11'-H), 0.87 (t, J11',12' = 7 Hz, 3 H, 12'-H)
ppm. 13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 105.3 (C-1), 76.4 (C-5),
69.9 (C-1'), 69.8 (C-2), 65.3 (C-6), 31.9, 29.7, 29.6, 29.4, 29.3, 28.9, 26.0,
25.9, 22.7 (C-3, C-4, and C-2' to C11'), 14.1 (C-12') ppm. HRMS: Calcd.
[C18H36NaO4] 339.2506; Found 339.2507 (error -0.3 ppm).
Antimicrobial assays and bacterial strains. For results presented in
table 1, the broth microdilution method on Müller-Hinton medium was
employed to determine the MIC values, according to the Clinical and
Laboratory Standards Institute (CLSI) guidelines.[14] Three strains of the B.
anthracis (INSA private collection), B. cereus (ATCC 11778) and E.
faecalis (ATCC 29212) were used. Compounds were incubated with
bacteria for 16 h at 37 °C prior to determining the MIC, which is defined as
the lowest concentration of the tested compounds at which no bacterial
growth was observed.
Methyl
2,6-di-O-pivaloyl-3,4-dideoxy-α-D-erythro-hexopyranoside
(25). [α]2퐷0= +82 º (c1; CHCl3); Rf (hex/EtOAc 3:1)= 0.67; 1H NMR (400.13
MHz, CDCl3, 25 ºC): δ = 4.78 (d, 3J1,2 = 3 Hz, 1 H, 1-H), 4.72 (ddd, 3J2,3ax
3
= 12 Hz, J2,3eq = 4 Hz, 1 H, 2-H), 4.11-4.00 (m, 2 H, 6-H), 3.97-3.89 (m,
1H, 5-H), 3.39 (s, 3 H, -OMe), 1.94 (qd, 3J3ax,3eq = 12 Hz, 3J3a,4e = 3J3a,4a
=
3
4 Hz, 1 H, 3ax-H), 1.84-1.77 (m, 1 H, 3eq-H), 1.72 (ddd, J4a,4e = 13 Hz,
4eq-H), 1.53 (qd, 1 H, 4ax-H), 1.21 (s, 9 H, -OPiv), 1.19 (s, 9 H, -OPiv)
ppm. 13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 178.3, 178.1 (C=O, Piv),
96.9 (C-1), 69.8 (C-2), 66.1 (C-5 and C-6), 55.0 (OMe), 38.8, 38.7 (Cq, -
OPiv), 27.2, 27.0 (CH3, -OPiv), 26.5 (C-4), 22.8 (C-3) ppm. HRMS: Calcd.
[C17H30NaO6] 353.1935; Found 353.1935 (error 0.0 ppm).
Cytotoxicity. Caco-2 and HepG2 cell culture and viability assays were
performed using a pre-established methodology.[15] Caco-2 and HepG2
cells were grown in DMEM high glucose supplemented with 10% foetal
bovine serum, glutamine (2 mM), penicillin (100 U/mL), and streptomycin
(100 g/mL), in a humidified incubator at 37 °C with a 5 % CO2
atmosphere. The cells were trypsinized twice a week with trypsin/EDTA
(0.05%/0.02%) and the medium was also changed twice a week.
Determination of cell growth was performed using the MTT [3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. On day 1,
20,000 cells/well were seeded into 96-well plates in a volume of 100 L.
On day 2, the different drugs concentration (0.1–100 M) were added to
the plate. In all the experiments, the various drug-solvents (EtOH, DMSO)
were added in each control to evaluate a possible solvent cytotoxicity. After
the established incubation time with drugs,10 L MTT (0.5 mg/mL) was
added to each well, and after 3-4 h incubation at 37 °C, the supernatant
was removed. The formazan crystals were solubilized using DMSO/EtOH
(1:1) (100 L) and the absorbance values at 570 nm and 630 nm were
determined on the microplate reader Victor3 from Perkin Elmer Life
Sciences.
Methyl 4-deoxy-2,6-di-O-pivaloyl-α-D-xylo-hexopyranoside (26). Rf
(hex/EtOAc 3:1)= 0.58; [α]2퐷0= +75 º (c1; CHCl3); Rf (hex/EtOAc 3:1)= 0.58;
1H NMR (400.13 MHz, CDCl3, 25 ºC): δ = 4.72 (d, 3J1,2 = 4 Hz, 1 H, H-1),
4.55 (s, 1 H, OH), 4.30-4.22 (m, 2 H, 3-H and 5-H), 4.15-4.02 (m, 3 H, 6-H
and 2-H), 3.43 (s, 3 H, -OMe), 2.02 (td, 3J4e,5 = 3J3,4e = 3 Hz, 3J4e,4a = 14 Hz,
1 H, 4ax-H), 1.83 (ddd, 3J4a,5 = 3J3,4a = 11 Hz, 1 H, 4ax-H), 1.21 (s, 9 H, -
OPiv) ppm. 13C NMR (100.62 MHz, CDCl3, 25 ºC): δ = 178.2 (C=O, Piv),
101.0 (C-1), 68.2 (C-2), 67.9, 68.8 (C-5 and C-6), 61.3 (C-3), 55.9 (OMe),
38.8 (Cq, -OPiv), 34.0 (C-4), 27.2 (CH3, -OPiv) ppm. HRMS: Calcd.
[C17H30NaO7] 369.1884; Found 369.1883 (error 0.1 ppm).
Dodecyl 3,4-dideoxy-D-erythro-hexopyranosides (27a,b). Compound
25 (0.260 g, 0.787 mmol) and Amberlyst 15 (0.050 g) were suspended in
dodecan-1-ol (2.41 mL, 10.75 mmol, 14 equiv.) and stirred at 95 ºC for 20
h. Reaction was then cooled to r.t., diluted with DCM, the A-15 beads were
filtered off and DCM was evaporated under reduced pressure. The residue
was ressuspended in 3 mL of MeOH:H2O 50:50, and potassium hydroxide
pellets (0.6 g) were added to the stirring solution. After 16 h at room
temperature, reaction was diluted with MeOH (3 mL) and neutralized with
IR-120. After filtration and evaporation of the solvent, the residue was
purified by CC, eluted with hex/acetone 4:1, affording the alfa anomer 27a
as a white solid in 36% yield (0.0896 g), and the beta-anomer 27b as a
colourless oil, in 14% yield (0.0338 g).
Acknowledgments
The European Union is gratefully acknowledged for the support of
the project “Diagnostic and Drug Discovery Initiative for
Alzheimer's Disease” (D3i4AD), FP7-PEOPLE-2013-IAPP, GA
612347. The authors thank the Management Authorities of the
European Regional Development Fund and the National Strategic
Reference Framework for the support of the Incentive System –
Research &Technological Development Co-Promotion FACIB
Project nr. 21457. Fundação para a Ciência e a Tecnologia is also
acknowledged for the support of project UID/Multi/0612/2013, and
for the Ph.D. grant SFRH/BDE/51998/2012 (CD), co-sponsored
by CIPAN.
Dodecyl
3,4-dideoxy-α-D-arabino-hexopyranoside
(27a).
Rf
(CyHex/EtOAc 1:3)=0.65; M.p. = 52.9.0-53.8°C; [α]2퐷0= +71 º (c1, CH2Cl2);
1H NMR (400.13 MHz, CDCl3, 25 ºC): δ = 4.66 (d, 3J1,2= 3 Hz, 1 H, H-1),
3.75-3.66 (m, 2 H, 5-H and 1'a-H), 3.55 (ddd, 3J2,3ax = 11 Hz, 3J2,3eq = 4 Hz,
3
1 H, 2-H), 3.46-3.37 (m, 2 H, 6-H and 1'b-H), 1.80 (qd, J3ax,3eq = 12 Hz,
3J2,3eq = 4 Hz, 1 H, 3eq-H), 1.75-1.68 (m, 1 H, 3ax-H), 1.67-1.54 (m, 3 H,
4eq-H and 2'-H), 1.45-1.34 (m, 3 H, 4ax-H, 3'-H), 1.33-1.21 (m, 16H, 4'-H
to 11'-H), 0.87 (t, 3J11',12' = 7 Hz, 1 H, 12'-H) ppm. 13C NMR (100.62 MHz,
CDCl3, 25 ºC): δ = δ 99.8 (C-1), 70.1 (C-5), 69.6 (C-2), 68.8 (C-1'), 65.9
(C-6), 33.1, 30.8, 30.7, 30.5, 23.8 (C-2', C-4' to C-11'), 27.8, 27.4, 27.3 (C-
3, C-4 and C-3'), 14.5 (C-12') ppm. HRMS: Calcd. [C18H36NaO4] 339.2506;
Found 339.2500 (error 1.6 ppm).
Keywords: antimicrobial • carbohydrate • deoxygenation •
anthrax
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
Ribeiro, M. J. Ferreira, C. Oliveira, M. Guisnet, Eur. J. Org.
Chem. 2006, 2429-2439.
References
[7]
[8]
J. G. Hurdle, A. J. O'Neill, I. Chopra, R. E. Lee, Nat. Rev.
Microbiol. 2011, 9, 62-75.
[1]
a) D. A. Sweeney, C. W. Hicks, X. Cui, Y. Li, P. Q. Eichacker,
Am. J. Resp. Crit. Care 2011, 184, 1333-1341; b) A. K. Goel,
World J. Clinic. Cases 2015, 3, 20-33.
V. Cachatra, A. Almeida, J. Sardinha, S. D. Lucas, A. Gomes, P.
D. Vaz, M. H. Florêncio, R. Nunes, D. Vila-Viçosa, M. J.
Calhorda, A. P. Rauter, Org. Lett. 2015, 17, 5622-5625.
D. Beaupere, I. Boutbaiba, G. Menailly, R. Uzan, Carbohydr. Res.
1988, 152-155.
P.J. Garegg, H. Hultberg, Carbohydr. Res. 1981, 93, C10-C11
S. Czernecki, J. M. Valery, J. Carbohydr. Chem. 1989, 8(5), 793-
798
R. J. Ferrier, N. Prasad, J. Chem Soc C: Organic 1969, 570-575.
A. P. Rauter, F. Piedade, T. Almeida, R. Ramalho, M. J.
Ferreira, R. Resende, J. Amado, H. Pereira, J. Justino, A. Neves,
F. V. M. Silva, T. Canda, Carbohydr. Res., 2004, 339, 1889 –
1897.
Clinical and Laboratory Standards Institute. Methods for Dilution
Antimicrobial Susceptibility Tests for Bacteria that Grow
Aerobically. Approved Standard, 10th ed, NCCLS document
M7–A4, 2015.
[2]
[3]
F. Celandroni, S. Salvetti, S. A. Gueye, D. Mazzantini, A. Lupetti,
S. Senesi, E. Ghelardi, PloS one 2016, 11, e0152831.
a) F. V. M. Silva, M. Goulart, J. Justino, A. Neves, F. Santos, J.
Caio, S. Lucas, A. Newton, D. Sacoto, E. Barbosa, M.-S. Santos,
A. P. Rauter, Bioorg. Med. Chem. 2008, 16, 4083-4092; b) A.
Martins, M. S. Santos, C. Dias, P. Serra, V. Cachatra, J. Pais, J.
Caio, V. H. Teixeira, M. Machuqueiro, M. S. Silva, A. Pelerito,
J. Justino, M. Goulart, F. V. Silva, A. P. Rauter, Eur. J. Org.
Chem. 2013, 1448-1459.
C. Dias, J. Pais, R. Nunes, A. F. Almeida, P. Serra, N. Xavier, D.
Vila-Viçosa, M. Machuqueiro, A. Viana, A. Martins, M. Santos,
A. Pelerito, R. Dias, R. Tenreiro, M. Oliveira, M. Contino, N.
Colabufo, R. Almeida, M. Sanchez-Blazquez, J. Marquês, A.
Rauter, Nat. Commun. 2018, 9, https://doi.org/10.1038/s41467-
018-06488-4.
[9]
[10]
[11]
[12]
[13]
[4]
[14]
[15]
[5]
[6]
N. Villandier, A. Corma, ChemSusChem 2011, 4, 508-513.
A. P. Rauter, F. Ramôa-Ribeiro, A. C. Fernandes, J. Figueiredo,
Tetrahedron 1995, 51, 6529-6540; bA. P. Rauter, T. Almeida, A.
I. Vicente, V. Ribeiro, J. C. Bordado, J. P. Marques, F. Ramôa
G. Nesi, N. A. Colabufo, M. Contino, M. G. Perrone, M.
Digiacomo, R. Perrone, A. Lapucci, M. Macchia, S. Rapposelli,
Eur. J. Med. Chem. 2014, 76, 558-566.
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201801764
European Journal of Organic Chemistry
FULL PAPER
Entry for the Table of Contents
FULL PAPER
Sugar deoxygenation
Catarina Dias, Alice Martins, Ana
Pelerito, Maria C. Oliveira,
Marialessandra Contino, Nicola A.
Colabufo, Amélia P. Rauter*
Page No. – Page No.
The fight against antibiotic resistance emergence relies on alternative antibiotics.
Approaches towards new dodecyl deoxy and dideoxy glycosides were devised and
compounds tested over Bacillus spp. and Enterococcus faecalis. The 4,6-
dideoxygenation pattern gave the most active glycoside against all microbes tested.
Assessing the optimal deoxygenation
pattern of dodecyl glycosides for
antimicrobial activity against Bacillus
anthracis
This article is protected by copyright. All rights reserved.