Preparation of new β-D-xyloside- and β-D-xylobioside-based ionic liquids through chemical and/or enzymatic reactions

Article abstract of DOI:10.1016/j.carres.2017.09.012

Several tetraalkylphosphonium and tetraalkylammonium salts containing xyloside- and xylobioside-based anionic moieties have been prepared. Two stereoselective routes have been developed: i) a chemical pathway in four steps from D-xylose, and ii) a chemoenzymatic pathway directly from biomass-derived xylans. These salts displayed interesting properties as ionic liquids. Their structures have been correlated to their thermal properties (melting, glass transition and decomposition temperatures).

Full text of DOI:10.1016/j.carres.2017.09.012

Carbohydrate Research 451 (2017) 72e80
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Preparation of new
b-D-xyloside- and b-D-xylobioside-based ionic
liquids through chemical and/or enzymatic reactions
S. Gatard a , R. Plantier-Royon , C. R eꢀ mond , M. Muzard , C. Kowandy ,
,
*
a
b
a
a
a, **
S. Bouquillon
a
Institut de Chimie Mol ꢀe culaire de Reims, CNRS UMR 7312, Universit ꢀe de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex, France
UMR FARE 614, Fractionnement des AgroRessources et Environnement, Chaire AFERE, Universit ꢀe de Reims-Champagne-Ardenne, INRA, 51686 Reims Cedex,
b
France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 September 2017
Received in revised form
Several tetraalkylphosphonium and tetraalkylammonium salts containing xyloside- and xylobioside-
based anionic moieties have been prepared. Two stereoselective routes have been developed: i) a
chemical pathway in four steps from D-xylose, and ii) a chemoenzymatic pathway directly from biomass-
derived xylans. These salts displayed interesting properties as ionic liquids. Their structures have been
correlated to their thermal properties (melting, glass transition and decomposition temperatures).
21 September 2017
Accepted 21 September 2017
Available online 23 September 2017
©
2017 Elsevier Ltd. All rights reserved.
Keywords:
Xyloside
Xylobioside
Xylans
Chemo-enzymatic synthesis
Ionic liquids
1
. Introduction
chiral discrimination or asymmetric organic reactions [12].
Lignocellulosic biomass represents an abundant source of
valuable molecules in a biorefinery context [13]. Among these
molecules, xylans, mainly constituted of xylose residues, generate a
growing interest for processing into various molecules of interest
[14], such as xylitol, ethanol, and might be building blocks of choice
for more complex molecules [15]. Xylans could represent 25e35%
of dry matter in graminaceous plants and in hardwoods and this
level could reach up to 50% in some tissues of cereal grains [16,17].
In this paper, following previous works on valorization of pentoses
into surfactants [18e20], glycodendrimers [21,22] or as ionic liquids
[23], we will describe the synthesis of xyloside- and xylobioside-
based ILs from D-xylose or directly from xylans.
Ionic Liquids (ILs) are compounds of importance due to their
potential applications in various fields such as catalysis [1,2], syn-
thetic chemistry [3e6], electrochemistry [7,8], solubilization and
transformation of biopolymers [9,10], etc … The wide variety of
combinations of cations and anions allows refining their physico-
chemical properties (melting temperature, viscosity, density, hy-
drophobicity, solubility …) for well-chosen applications. For
example, their low volatility makes them compounds of choice for
greener solvents as alternatives to common organic solvents. Their
development is therefore part of a sustainable development
strategy.
In this context, one approach to produce greener ILs is to use
renewable resources such as D-glucose or D-xylose the most
abundant carbohydrates in the plant kingdom [11,12]. Some ex-
amples of ILs based on fructose, glucose derivatives, isomannide or
isosorbide were recently reported for their uses as solvents for
Our work is also part of an approach to assess how the physi-
cochemical properties of ILs vary with different anion/cation as-
sociations. For this purpose, we designed a general structure of
xyloside- and -D-xylobioside-based ILs with a modular amphi-
philic anionic structure that can be divided into three blocks
Scheme 1): i) a polar head containing one or two xylose units, ii) a
b-D-
b
(
modular linker on the anomeric position of the sugar (methylene,
pentyl, benzyl or triazolyl), and iii) a carboxylate anion type, which
makes these ILs very attractive for various applications [24e27]. As
*
Corresponding author.
** Corresponding author.
E-mail addresses: sylvain.gatard@univ-reims.fr (S. Gatard), sandrine.
þ
þ
4
4
counter cations, we chose tetralkylammonium ( NBu , NHex ) or
bouquillon@univ-reims.fr (S. Bouquillon).
https://doi.org/10.1016/j.carres.2017.09.012
0
008-6215/© 2017 Elsevier Ltd. All rights reserved.

S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
73
Scheme 1. Chemical and chemo-enzymatic pathways to access to the b-D-xyloside- and b-D-xylobioside-based ILs.
þ
-
phosphonium ( PBu
4
), which are large cations and generate salts
2.2. Analysis
with lower melting points than imidazolium- or pyridinium-based
ILs [3].
1H (500.1 MHz, 600.2 MHz), 13C (125.0 MHz,150.0 MHz) and 31P-
NMR (202.4 MHz) spectra were recorded on an AC 500 and AC 600
To access to these salts, two stereoselective routes have been
developed. In a chemical pathway from D-xylose, peracetylated
b
-
2
Bruker instruments in D O or DMSO-d6. Chemical shifts are
D-xylopyranose was first glycosylated with a hydroxyester in the
presence of a Lewis acid. After deacetylation, a subsequent sapon-
ification reaction was carried out to form the b-D-xyloside-based
ILs. In a chemo-enzymatic strategy from xylans, an enzymatic
transglycosylation catalyzed by a xylanase followed by a saponifi-
cation step led to both b-D-xyloside- and b-D-xylobioside-based
expressed in parts per million (ppm), coupling constants jJ j are
given in Hertz (Hz) and pattern abbreviations are s for singlet, d for
doublet, dd for doublet of doublet, t for triplet, q for quartet, quint
for quintuplet, sext for sextuplet and m for multiplet. IR spectra
were recorded on a Perkin Elmer spectrometer (UATR Two). C and H
analyses were performed on a Perkin Elmer 2400 CHN equipment.
ILs. The range of ILs has also been expanded by introducing a tri-
azolyl linker through a copper-catalyzed azide-alkyne cycloaddi-
tion (CuAAC), which appeared as an increasingly popular tool to
synthesize ionic liquids [23,28e30]. The melting, glass transition
and decomposition temperatures of all the b-D-xyloside- and b-D-
xylobioside-based ILs were then measured in order to determine
their liquidus range.
Chromatographies were carried out on MN Silica 60 (40e63 mm) or
Silica 60 F254 (TLC plates). ESI-HRMS spectra were obtained on a
hybrid tandem quadrupole/time-of-flight (Q-TOF) instrument,
equipped with a pneumatically assisted electrospray (Z-spray) ion
source (Micromass, Manchester, UK) operated in positive and
negative mode. The electrospray potential was set to 3 kV in posi-
ꢀ1
tive ion mode (flow of injection 5 mL min ) and the extraction cone
voltage was usually varied between 30 and 90 V. Optical rotations
were measured on a Perkin Elmer 241 polarimeter. The DSC ex-
periments were carried out on a Q100 TA instruments heat flux
ꢀ
1
2
. Experimental section
differential calorimeter at a heating rate of 5 K min under a
ꢀ1
constant flow of dry nitrogen (50 mL min ). Aluminum crucibles
were loaded with around 2 mg of sample. The decomposition
temperatures of the ILs were measured using a Q500 TA in-
struments, with the mass of TGA samples varying between 10 and
20 mg (protocol followed: flow of dry nitrogen at 60 mL min on
sample; isotherm for 5 min at 50 C to stabilize the apparatus and
2.1. Materials
Methyl 6-hydroxyhexanoate [31] and compounds 1 [32] and 15
ꢀ1
[33] were synthesized as previously described in the literature. A
ꢁ
recombinant thermophilic family 10 endo-xylanase (Tx-xylanase)
from Thermobacillus xylanilyticus was produced by E. coli BL21
ꢁ
ꢁ
purge the oven; heating from 50 C to 400 C at a rate of
ꢀ1
ꢁ
(
DE3) using a previously established protocol [34]. All other re-
10 K min ; isotherm for 15 min at 400 C; for liquid or viscous
samples, an aluminum capsule was used to avoid fouling the
measurement platform).
agents were commercially available and used as received. CH Cl
was dried using a Pure Solv solvent drying system over aluminum
oxide under an argon atmosphere before use.
2
2

74
S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
2
2
.3. Synthesis
NCH
2
CH
2
CH
2
CH
3
), 1.40 (8H, sext, 3J 7.4, NCH
CH CH CH ), 3.20e3.26 (8H, m,
), 3.32e3.40 (2H, m, 2-H, 5-H), 3.49 (1H, t,
2 2 2 3
CH CH CH ),
1.65e1.73 (8H, m, NCH
2
2
2
3
.3.1. General procedure for the glycosylation and deacetylation
NCH
2
CH
2
CH
2
CH
3
3
3
3
reactions
To a solution of 1,2,3,4-tetra-O-acetyl-
equiv) and the corresponding alcohol (1.2 equiv, ethyl glycolate,
methyl 6-hydroxyhexanoate or methyl 4-(hydroxymethyl)benzo-
ate) in CH
J
J
3,2 ¼ J3,4 9.2, 3-H), 3.63e3.69 (1H, m, 4-H), 3.98 (1H, dd, J5,4 5.4,
2
3
3
b
-D-xylopyranose 1 (1.0
5,5 11.6, 5-H), 4.10 (1H, d, J 15.5, OCH
2
), 4.27 (1H, d, J 15.5, OCH
2
),
3
13
ꢁ
4.45 (1H, d, J1,2 7.7, 1-H); C NMR (150 MHz, D
(NCH
(NCH
2
CH
O, 25 C):
d
¼ 12.8
2
CH
2
CH
CH
2
CH
3
),
19.2
(NCH
2
CH
2
2
CH
3
),
23.2
ꢁ
2
Cl
2
was added BF
3
.Et
2
O (1.5 equiv) at 0 C under Ar. After
2
CH
2
2
CH
3
), 58.2 (NCH
2
CH CH CH ), 65.2 (C-5), 68.5
2
2
3
stirring for 2 h, at room temperature, the organic mixture was
washed with a saturated solution of NaHCO and water, dried over
Na SO and concentrated to dryness under reduced pressure.
To a solution of the previously xyloside obtained in MeOH was
(OCH
(ATR, neat): 1590 cm (C¼O); elemental analysis: calcd (%) for
: C 61.44, H 10.53, N 3.11; found: C 61.50, H 10.54, N 3.11.
2
), 69.2 (C-4), 73.0 (C-2), 75.5 (C-3), 103.1 (C-1), 177.2 (C¼O); IR
ꢀ1
3
2
4
23 7
C H47NO
ꢁ
20
IL 6. Yield 77%, white solid, m.p. 72 C; [
a
]
D
¼ ꢀ15.1 (c¼0.40 in
1
ꢁ
3
added Na (10.0 mol %) under Ar. After stirring for 1 h at room
H
2
O); H NMR (600 MHz, D
2
O, 25 C):
d
¼ 0.88 (12H, t, J 7.4,
þ
temperature, the mixture was neutralized with DOWEX (H ),
NCH
NCH
NCH
2
2
2
CH
CH
2
CH
2
CH
CH
2
CH
CH
2
CH
CH
3
),
),
1.30e1.37
1.63e1.67
3.15e3.20
(24H,
(8H,
(8H,
m,
m,
m,
filtered and concentrated to dryness under reduced pressure.
Xyloside 2 was obtained as a white solid and was characterized
without any further purification. The xyloside 3 was purified by
2
CH
CH
CH
2
2
2
2
2
3
CH
2
CH
CH
2
2
CH
CH
2
CH
CH
3
),
NCH
2
CH
2
2
3
), 3.28e3.35 (2H, m, 2-H, 5-H), 3.44 (1H, t,
3
3
3
flash chromatography over silica gel with eluting mixture CH
2
Cl
2
/
J
J
3,2 ¼ J3,4 9.0, 3-H), 3.58e3.65 (1H, m, 4-H), 3.93 (1H, dd, J5,4 5.4,
2
2
2
MeOH: 8:2 to afford a white solid. In the case of xyloside 4, the
5,5 11.6, 5-H), 4.04 (1H, d, J 15.5, OCH
2
), 4.22 (1H, d, J 15.5, OCH
2
),
3
13
ꢁ
residue was washed with CH
compound.
2
Cl
2
(3 ꢂ 50 mL) to afford a pure
4.39 (1H, d, J1,2 7.7, 1-H); C NMR (150 MHz, D
2
O, 25 C):
d
¼ 13.2
(NCH
(NCH
(NCH
2
2
2
CH
CH
CH
2
2
2
CH
CH
CH
2
2
2
CH
CH
CH
2
2
2
CH
2
CH
CH
CH
3
3
3
), 20.9 (NCH
), 25.2 (NCH
), 58.1 (NCH
2
CH
CH
CH
2
CH
CH
CH
2
CH
CH
CH
2
CH
CH
CH
2
CH
CH
CH
3
), 21.7
Xyloside 2. Yield 72%, white solid, m.p. 95 C; 1H NMR
ꢁ
CH
2
), 30.4
3
), 65.2
2
2
2
2
2
3
ꢁ
3
2
(
3
600 MHz, D
.34 (1H, dd,
2
O, 25 C):
d
¼ 3.29 (1H, dd, J5,4 10.6, J5,5 11.6, 5-H),
CH
2
2
2
2
2
2
3
2,1 7.8, 3
2,3 9.3, 2-H), 3.44 (t, 3J3,2
3
J
J
¼
J
3,4 9.3, 3-H),
(C-5), 68.5 (OCH
2
), 69.1 (C-4), 73.0 (C-2), 75.5 (C-3), 103.1 (C-1),
3
ꢀ1
3
J
.60e3.62 (1H, m, 4-H), 3.78 (3H, s, OCH
3
), 3.95 (1H, dd,
J
5,4 5.5,
177.0 (C¼O); IR (ATR, neat): 1602 cm (C¼O); elemental analysis:
2
3
13
5,5 11.6, 5-H), 4.43 (2H, s, OCH
2
), 4.44 (1H, d, J1,2 7.8,1-H); C NMR
), 65.2 (C-5), 66.2 (OCH ), 69.1
calcd (%) for C31
11.51, N 2.94.
7
H63NO : C 66.27, H 11.30, N 2.49; found: C 66.67, H
ꢁ
(
150 MHz, D
2
O, 25 C):
d
¼ 52.5 (OCH
3
2
2
0
O); 1H NMR
CH CH CH ),
), 1.49e1.59 (8H, m,
CH CH CH ), 3.28e3.35
(2H, m, 2-H, 5-H), 3.34 (1H, t, J3,2 ¼ J3,4 9.2, 3-H), 3.58e3.65 (1H,
(
C-4), 72.7 (C-2), 75.5 (C-3), 102.9 (C-1), 172.3 (C¼O); IR (ATR, neat):
IL 7. Yield 96%, oily, [
a
d
]
D
¼ ꢀ25.3 (c ¼ 0.40 in H
2
ꢀ
1
þ
ꢁ
3
1
2
C
748 cm (C¼O); ESI-HRMS: m/z calcd for C
8
H14NaO
7
: [MþNa] :
(500 MHz, D
1.46 (8H, sext,
PCH CH CH CH
2
O, 25 C):
¼ 0.92 (12H, t, J 7.4, PCH
7.4, PCH CH CH CH
), 2.11e2.19 (8H, m, PCH
2
2
2
3
3
45.0637; found: 245.0627; elemental analysis: calcd for
J
2
2
2
3
8 14
H
O
7
þ0.25 H
2
O: C 42.38, H 6.44; found: C 42.12, H 6.24.
2
2
2
3
2
2
2
3
Xyloside 3. Yield 26%, white solid, m.p. 92 C; 1H NMR
ꢁ
3
3
ꢁ
3
2
3
(
600 MHz, D
2
O, 25 C):
d
¼ 1.33e1.39 (2H, m, OCH
2
CH
2
CH
2
CH
2
3
CH
2
),
m, 4-H), 3.94 (1H, dd, J5,4 5.4, J5,5 11.6, 5-H), 4.04 (1H, d, J 15.5,
3
3
13
1.52e1.58 (2H, m, OCH
2
CH CH CH CH
2
2
2
2
), 1.61 (2H, quint, J 7.6,
OCH
(125 MHz, D
2
), 4.23 (1H, d, J 5.5, OCH
2
), 4.40 (1H, d, J1,2 7.7, 1-H); C NMR
CH CH CH ), 17.6 (d, J 48.2,
CH CH CH ), 23.2 (d, J 15.3,
), 65.2 (C-5), 68.5 (OCH ), 69.2 (C-4), 73.0 (C-2)
O,
); IR (ATR, neat): 1594 cm (C¼O);
3
ꢁ
OCH
2
CH
2
CH
2
CH
2
CH
2
), 2.41 (2H, t, J 7.4, OCH
2
CH
2
CH
2
CH
2
CH
2
), 3.23
2
O, 25 C):
d
¼ 12.5 (PCH
2
2
2
3
3
3
3
2
(
(
1H, dd, J2,1 7.9, J2,3 9.3, 2-H), 3,31 (1H, t, J5,4 ¼ J5,5 11.7, 5-H), 3.42
PCH
PCH
2
CH
CH
2
CH
CH
2
CH
CH
3
), 22.6 (d, J 4.5, PCH
2
2
2
3
3
3
3
1H, t, J3,2 ¼ J3,4 9.3, 3-H), 3.59 (2H, t, J 6.5, OCH
2
CH
2
CH
2
CH
2
CH
2
),
2
2
2
3
2
3
31
3
.69 (3H, s, OCH
3
), 3.83e3.88 (1H, m, 4-H), 3.86 (1H, dd,
J
5,4 5.4,
75.5 (C-3), 103.1 (C-1), 177.0 (C¼O); P NMR (202.4 MHz, D
2
2
3
13
ꢁ
ꢀ1
J5,5 11.7, 5-H), 4.38 (1H, d, J1,2 7.9, 1-H); C NMR (150 MHz, D
2
O,
25 C, TMS):
d
¼ 33.25 (s, PBu
4
ꢁ
2
5
C):
d
¼
24.5
30.8
(OCH
(OCH
), 61.5 (OCH
2
CH
2
CH
2
CH
CH
CH
2
CH
CH
CH
2
),
),
CH
28.4
33.5
elemental analysis: calcd (%) for C23
47
H O
7
P: C 59.21, H 10.15; found:
(
(
OCH
OCH
2
CH
CH
2
CH
2
CH
CH
2
CH
2
),
2
CH
2
CH
2
2
2
C 59.35, H 10.42.
2
0
O); 1H NMR
2
2
CH
2
2
CH
2
), 48.8 (OCH
3
2
2
2
2
CH
2
),
IL 8. Yield 99%, oily, [
a
d
]
D
¼ ꢀ22.6 (c ¼ 0.18 in H
2
ꢁ
3
6
5.0 (C-5), 70.3 (C-4), 72.9 (C-2), 75.7 (C-3), 102.9 (C-1), 177.5
(600 MHz, D
1.31e1.39 (10H, m, OCH
(2H, quint,
2
O, 25 C):
¼ 0.93 (12H, t, J 7.6, NCH
CH CH CH CH , NCH CH
7.6, OCH CH CH CH CH
NCH CH CH CH
2
CH CH CH ),
CH CH ), 1.56
), 1.60e1.67 (10H, m,
2
2
3
ꢀ1
(
C
C¼O); IR (ATR, neat): 1728 cm (C¼O); ESI-HRMS: m/z calcd for
2
2
2
2
2
2
2
2
3
þ
3
12
H
22NaO
7
: [MþNa] : 301.1263; found: 301.1259.
J
2
2
2
2
2
Xyloside 4. Yield 70%, white solid, m.p. 148 C; 1H NMR
ꢁ
OCH
OCH
CH
CH
CH
CH
CH
CH
CH
,
), 2.16 (2H, t,
3
J
7.5,
2
2
2
2
2
2
2
2
2
3
ꢁ
(
600 MHz, D
J
2
O, 25 C):
d
¼ 3.32e3.36 (2H, m, 2-H, 5-H), 3.45 (1H, t,
2
2
CH
2
2
), 3.15e3.20 (8H, m, NCH CH CH CH ), 3.21
2 2 2 3
3
3
3
3
3
2
3,2 ¼ J3,4 9.2, 3-H), 3.63e3.67 (1H, m, 4-H), 3.96 (3H, s, OCH
3
), 3.99
(1H, dd, J2,1 7.9, J2,3 9.3, 2-H), 3.27 (1H, t, J5,4 ¼ J5,5 11.7, 5-H), 3.40
3
2
3
3 3
(
1H, dd, J5,4 5.4, J5,5 11.3, 5-H), 4.52 (1H, d, J1,2 7.8, 1-H), 4.84 (1H,
(1H, t, J3,2 ¼ J3,4 9.3, 3-H), 3.56e3.60 (1H, m, 4-H), 3.63e3.67 (1H,
3
3
3
d, J 13.3, OCH
8
2
), 4.97 (1H, d, J 13.3, OCH
2
), 7.58 (1H, d, J 8.1, CHAr),
m, OCH
2
CH
2
CH
2
CH
2
CH
2
), 3.82e3.87 (1H, m, OCH
2
CH
2
CH
2
CH
2
CH
2
),
C
3
13
ꢁ
3
2
3
13
.06 (1H, d, J 8.1, CHAr); C NMR (150 MHz, D
2
O, 25 C):
), 73.0 (C-2), 75.7 (C-3),
d
¼ 52.7
3.91 (1H, dd, J5,4 5.7, J5,5 11.7, 5-H), 4.37 (1H, d, J1,2 7.9, 1-H);
ꢁ
(
OCH
3
), 65.2 (C-5), 69.2 (C-4), 70.8 (OCH
2
NMR (150 MHz, D
2
O, 25 C):
23.1
d
¼ 12.8 (NCH
(NCH CH CH
CH CH CH
CH CH CH
69.2
2
CH
CH
CH
CH
2
CH
2
),
CH
3
), 19.1
25.0
28.5
58.1
1
02.4 (C-1), 128.2 (CHAr), 129.2 (CqAr), 129.7 (CHAr), 142.5 (CqAr),
(NCH
(OCH
(OCH
2
2
2
2
CH
CH
CH
CH
2
2
2
2
CH
CH
CH
CH
2
CH
2
CH
2
CH
2
CH
2
CH
3
2
2
3
2
),
2
2
2
3
ꢀ1
169.2 (C¼O); IR (ATR, neat): 1713 cm (C¼O); ESI-HRMS: m/z calcd
CH
CH
),
2
2
),
),
25.6
37.5
65.1
(OCH
(OCH
2
2
2
2
2
),
),
þ
for C14
H18NaO
7
: [MþNa] : 321.0950; found: 321.0952.
2
2
2
2
2
(NCH
(C-5),
(C-4),
70.5
2.3.2. General procedure for the saponification reactions
(OCH
2
CH
2
CH
CH
2
), 73.0 (C-2), 75.7 (C-3), 102.9 (C-1), 183.8
ꢀ
1
Compounds 2e4 and 16 (1.0 equiv) were dissolved in distilled
water. An aqueous solution of NBu OH (1 equiv) or PBu OH (1
OH (1 equiv) was then added, and the mixture was
(C¼O); IR (ATR, neat): 1563 cm (C¼O); elemental analysis: calcd
4
4
(%) for C27 O: C 62.45, H 10.97, N 2.69; found: C
H55NO
7
þ0.75 H
2
equiv) or NHex
4
62.28, H 11.10, N 2.80.
ꢁ
20
O); 1H NMR
stirred at 50 C for 1 h. After lyophilization, compounds 5e13 and
IL 9. Yield 94%, oily, [
a
]
D
¼ ꢀ15.1 (c ¼ 0.13 in H
2
ꢁ
3
1
9e21 were isolated and characterized without further
purification.
IL 5. Yield 98%, white solid, [
(600 MHz,
D
2
O, 25
CH CH
, NCH
CH ), 1.61e1.67 (10H, m, OCH
C):
d
¼
0.88 (12H, t,
1.30e1.37 (26H,
CH CH CH CH
J
7.0,
NCH
OCH
7.6, OCH
2
CH
CH
2
2
2
CH
2
CH
2
2
3
),
m,
2
0
1
3
a
ꢁ
]
D
¼ ꢀ25.7 (c ¼ 0.40 in H
2
O); H
2
CH
CH
2
CH
CH
2
CH
CH
2
2
CH
2
2
2
2
3
), 1.57 (2H, quint,
CH CH CH
J
3
NMR (600 MHz,
D
2
O, 25 C):
d
¼
0.99 (12H, t,
J
7.3,
2
2
2
2
2
2
2
2
CH
2
,

S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
75
3
NCH
2
CH
2
CH
2
CH
2
CH
2
CH
3
), 2.17 (2H, t, J 7.4, OCH
2
CH
2
CH
2
CH
J
2
CH
2
),
elemental analysis: calcd (%) for C37
10.58, N 2.18; found: C 69.01, H 10.75, N 2.23.
H
67NO
7
þ0.1 H
2
O: C 69.46, H
3
3
J
.17e3.19 (8H, m, NCH
2
CH CH CH CH CH ), 3.21 (1H, dd,
2
2
2
2
3
2,1 7.9,
3
3
2
3
3
20
1
2,3 9.3, 2-H), 3.28 (1H, t, J5,4 ¼ J5,5 11.7, 5-H), 3.40 (t, J3,2 ¼ J3,4
IL 13. Yield 99%, oily, [
a
]
D
¼ ꢀ28.6 (c ¼ 0.12 in H
2
O); H NMR
ꢁ
3
9
.3, 3-H), 3.57e3.62 (1H, m, 4-H), 3.64e3.68 (1H, m,
(600 MHz, D
1.43 (8H, sext,
PCH CH CH CH
(2H, m, 2-H, 5-H), 3.41 (1H, t, J3,2 ¼ J3,4 9.2, 3-H), 3.58e3.65 (1H,
2
O, 25 C):
d
¼ 0.91 (12H, t, J 7.3, PCH
7.2, PCH CH CH CH ), 1.47e1.54 (8H, m,
), 2.07e2.14 (8H, m, PCH CH CH CH ), 3.24e3.39
2 2 2 3
CH CH CH ),
3
OCH
dd,
2
CH
2
CH
2
CH
J
2
CH
2
), 3.85 (1H, m, OCH
2
CH
2
CH
2
CH
1,2 7.9, 1-H); C NMR
CH CH CH CH ), 20.9
CH CH CH CH ), 25.0
CH CH CH CH
CH CH CH CH
), 37.5 (OCH CH CH CH
2
CH
2
), 3.91 (1H,
J
2
2
2
3
3
2
3
13
J
5,4 5.7,
5,5 11.7, 5-H), 4.38 (1H, d,
J
2
2
2
3
2
2
2
3
ꢁ
3
3
(
(
(
(
(
(
(
(
(
150 MHz, D
NCH
OCH
OCH
NCH
2
2
2
2
O, 25 C):
d
¼ 13.2 (NCH
), 21.7 (NCH
), 25.1 (NCH CH
(OCH
2
CH
2
2
2
2
3
3
2
3
2
CH
CH
CH
2
CH
2
CH
2
CH
CH
CH
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
2
2
2
2
2
CH
3
2
CH
2
2
2
2
3
m, 4-H), 3.95 (1H, dd, J5,4 5.5, J5,5 11.6, 5-H), 4.47 (1H, d, J1,2 7.9, 1-
2
2
2
2
2
2
2
2
2
3
),
), 25.6
30.4
H), 4.75 (1H, d, J 12.0, OCH
2
), 4.90 (1H, d, J 12.0, OCH
J 8.0, CHAr), 7.83 (2H, d, J 8.0, CHAr); C NMR (150 MHz, D
2
), 7.44 (2H, d,
3
3
13
),
CH
CH
28.6
2
2
2
2
2
2
O,
ꢁ
2
CH
2
CH
CH
2
2
CH
CH
CH
3
2
2
2
2
CH
2
), 58.1
25 C):
d
¼ 12.5 (PCH
CH
65.1 (C-5), 69.2 (C-4), 71.0 (OCH
2
CH
2
CH
2
CH
3
), 17.6 (d, J 48.2, PCH
2
CH
2
CH
CH
2
CH
CH
3
),
),
NCH
OCH
2
CH
CH
2
3
), 65.1 (C-5), 69.2 (C-4), 70.5
22.6 (d, J 4.6, PCH
2
2
CH
2
CH
3
), 23.2 (d, J 15.3, PCH
2
CH
2
2
3
2
2
CH
2
), 73.0 (C-2), 75.8 (C-3), 102.9 (C-1), 183.7
2
), 73.0 (C-2), 75.7 (C-3), 102.2 (C-1),
ꢀ1
31
C¼O); IR (ATR, neat): 1566 cm (C¼O); elemental analysis: calcd
%) for C35 O: C 66.10, H 11.56, N 2.20; found: C 66.40, H
þH
1.39, N 2.42.
128.0 (CHAr), 129.0 (CHAr), 136.2 (CqAr), 139.5 (CqAr), 175.0 (C¼O);
P
ꢁ
H71NO
7
2
NMR (202.4 MHz, D
neat): 1597 cm
2
O, 25 C, TMS): ¼
4
d33.21 (s, PBu ); IR (ATR,
ꢀ
1
1
(C¼O); elemental analysis: calcd (%) for
2
0
1
IL 10. Yield 96%, oily, [
a
]
D
¼ ꢀ20.1 (c ¼ 0.15 in H
2
O); H NMR
CH CH CH ),
), 1.44 (8H, sext, J 7.3,
), 1.50e1.55 (10H, m, OCH CH CH CH CH
), 1.57e1.63 (2H, m, OCH CH CH CH CH
CH CH CH CH , PCH CH CH CH ), 3.21
1H, dd, J2,1 7.9, J2,3 9.3, 2-H), 3.29 (1H, t, J5,4 ¼ J5,5 11.6, 5-H), 3.40
C
29
H
51
O
7
Pþ1.25 H
2
O: C 61.62, H 9.54; found: C 61.71, H 9.48.
ꢁ
3
20
O); 1H NMR
CH CH ),
), 1.58e1.66 (8H, m,
CH CH CH ), 3.27 (1H,
dd, J2,1 8.0, J2,3 9.0, 2-H), 3.34 (1H, t, J5,4 ¼ J5,5 11.3, 5-H), 3.42 (1H,
(
600 MHz, D
2
O, 25 C):
d
¼ 0.91 (12H, t, J 7.3, PCH
2
2
2
3
IL 14. Yield 95%, oily, [
a]
D
¼ ꢀ23.9 (c 4.10 in H
2
3
3
ꢁ
3
1.34 (2H, quint, J 7.2, OCH
2
CH CH CH CH
2
2
2
2
(500 MHz, D
1.35 (8H, sext,
NCH CH CH CH
2
O, 25 C):
d
¼ 0.92 (12H, t, J 7.2, NCH
7.2, NCH CH CH CH
), 3.13e3.17 (8H, m, NCH
2
CH
2
2
3
3
PCH
PCH
2
2
CH
CH
2
CH
CH
2
CH
CH
3
3
2
2
2
2
2
,
J
2
2
2
3
2
2
2
2
2
2
2
),
2
2
2
3
2
2
2
3
3
3
3
2
2
.12e2.17 (10H, m, OCH
2
2
2
2
2
2
2
2
3
3
3
3
2
3
3
3
(
(
t, J3,2 ¼ J3,4 ¼ 9.0, 3-H), 3.58e3.65 (1H, m, 4-H), 3.97 (1H, dd, J5,4
2 3 2
3
3
1H, t, J3,2 ¼ J3,4 9.3, 3-H), 3.56e3.60 (1H, m, 4-H), 3.62e3.66 (1H,
5.5,
OCH
J
5,5 11.3, 5-H), 4.52 (1H, d,
J1,2 8.0, 1-H), 4.87 (1H, d, J 12.5,
2
m, OCH
3
NMR (150 MHz, D
2
CH
2
CH
2
CH
2
CH
2
), 3.82e3.86 (1H, m, OCH
2
CH
2
CH
2
CH
2
CH
2
),
C
2
), 4.97 (1H, d, J 12.5, OCH
(1H, s, H-triazolyl); C NMR (125 MHz, D
2
), 5.10 (2H, s, triazolyl-CH ), 8.00
2
3
2
3
13
13
ꢁ
.91 (1H, dd, J5,4 5.5, J5,5 11.6, 5-H), 4.37 (1H, d, J1,2 7.9, 1-H);
2
O, 25 C):
CH CH ),
3
CH CH CH ), 62.4 (tri-
d
¼ 13.3
ꢁ
2
O, 25 C, TMS):
CH CH ), 22.6 (d, J 4.5, PCH
CH CH ), 25.0 (OCH CH
CH CH
69.2
d
¼ 12.5 (PCH
CH
CH
CH
2
CH
CH
CH
CH
2
CH
CH
CH
2
CH
3
), 17.6
(NCH
(NCH
2
CH
2
CH
CH
2
CH
3
),
19.6
(NCH
), 58.5 (NCH
2
CH
2
2
3
23.6
(
J
d, J 48.2, PCH
15.3, PCH
2
CH
CH
2
2
3
2
2
2
3
), 23.2 (d,
2
CH
2
2
CH
3
), 53.6 (OCH
2
2
2
2
2
2
2
3
2
2
2
2
2
),
), 25.6
37.5
2
azolyl-CH ), 63.4 (C-5), 69.6 (C-4), 74.1 (C-2), 76.0 (C-3), 102.3 (C-1),
ꢀ
1
(
(
(
(
(
OCH
OCH
OCH
2
CH
CH
CH
2
2
2
CH
CH
CH
2
CH
CH
CH
2
CH
2
CH
2
CH
2
2
2
),
),
28.5
65.1
(OCH
(C-5),
2
2
2
2
2
126.7 (C-H triazolyl), 143.8 (C-triazolyl), 173.4 (C¼O); IR (cm ):
2
2
(C-4),
70.5
1620, 2784, 2957, 3445, 2957, 2784; elemental analysis: calcd (%)
2
2
), 73.0 (C-2), 75.8 (C-3), 102.9 (C-1), 183.7
50 4 7
for C26H N O : C 58.84, H 9.49, N 10.54; found: C 58.47, H 9.70, N
3
1
ꢁ
C¼O); P NMR (202.4 MHz, D
2
O, 25 C):
d
¼ 33.23 (s, PBu
4
); IR
10.33.
ꢀ
1
20
1
ATR, neat): 1565 cm (C¼O); elemental analysis: calcd (%) for
O: C 60.99, H 10.62; found: C 60.80, H 10.51.
IL 19. Yield, 95%, white solid, [
a
]
D
¼ ꢀ39.0 (c ¼ 0.34 in H
2
O); H
ꢁ
3
C
27
H
55
O
7
Pþ0.5 H
2
NMR (600 MHz,
NCH CH CH CH
1.60e1.67 (8H, m, NCH
D
2
O, 25 C):
d
¼
0.93 (12H, t,
7.4, NCH CH CH
J
7.6,
CH ),
2
0
1
3
IL 11. Yield 88%, white solid, [
NMR (500 MHz,
a
]
D
¼ ꢀ24.3 (c ¼ 0.40 in H
2
O); H
2
2
2
3
), 1.34 (8H, sext,
CH CH
J
2
2
2
3
ꢁ
3
D
2
O, 25 C):
d
¼
0.92 (12H, t,
7.4, NCH CH CH
J
7.4,
CH ),
2
2
2
CH
3
), 3.13e3.22 (8H, m,
3
3
3
0
NCH
2
CH
2
CH
2
CH
3
), 1.32 (8H, sext,
CH CH
), 3.27e3.32 (2H, m, 2-H, 5-H), 3.41 (1H, t,
J
2
2
2
3
NCH
2
CH
¼
2
CH
J
2
0
CH
3
), 3.24 (1H, dd, J
2
0
,1
0
7.8, J
2
0
,3
0
9.1, 2 -H), 3.29 (1H, t,
3
2
0
1.55e1.64 (8H, m, NCH
2
2
2
CH
3
), 3.11e3.14 (8H, m,
J
J
5
0
,4’
5
0
,5
11.6, 5 -H), 3.34e3.38 (2H, m, 2-H, 5-H), 3.41 (1H, t,
3
3
3
3
0
0 0
9.1, 3 -H), 3.58e3.63
3 ,4
NCH
J
2
CH
2
CH
2
CH
3
3,2 ¼ J3,4 9.3, 3-H), 3.56 (1H, t, J
3
0
,2’ ¼ J
3
3
3
0
3
2
3,2 ¼ J3,4 9.2, 3-H), 3.57e3.64 (1H, m, 4-H), 3.94 (1H, dd, J5,4 5.4,
(1H, m, 4 -H), 3.74e3.80 (1H, m, 4-H), 3.95 (1H, dd, J
5
0
,4
0
5.5, J
5
0
,5
0
2J5,5 11.6, H-5), 4.47 (1H, d, J1,2 7.8, 1-H), 4.75 (1H, d, J 12.0, OCH
3
2
),
11.6, 5 -H), 4.05 (1H, d, J 15.6, OCH
0
2
), 4.06 (1H, dd, J5,4 5.3, J5,5 11.7,
3
2
2
2
2
3
3
2
3
4
.90 (1H, d, J 12.0, OCH
2
), 7.47 (2H, d, J 8.3, CHAr), 7.87 (2H, d, J 8.3,
5-H), 4.22 (1H, d, J 15.6, OCH
2
), 4.42 (1H, d, J1,2 7.7, 1-H), 4.44 (1H,
7.8, 1 -H); C NMR (150 MHz, D
13
ꢁ
3
0
13
ꢁ
CHAr); C NMR (125 MHz, D
9.1 (NCH CH CH CH ),
NCH CH CH CH
5.7 (C-3), 102.3 (C-1), 128.0 (CHAr), 129.1 (CHAr), 136.3 (CqAr), 139.6
2
O, 25 C):
d
¼ 12.8 (NCH
2
CH
CH
), 73.0 (C-2),
2
CH
2
CH
58.0
3
),
d,
J
1
0
,2
0
2
O, 25 C):
d
¼ 12.8
1
(
7
2
2
2
3
23.1
(NCH CH CH
2
2
2
3
),
(NCH
(NCH
68.4 (OCH
2
CH
2
CH
CH
2
CH
3
),
19.1
(NCH
CH CH
2
CH
2
CH
2
CH
3
),
23.1
0
2
2
2
3
), 65.1 (C-5), 69.2 (C-4), 71.0 (OCH
2
2
CH
2
2
CH
3
), 58.0 (NCH
2
CH
2
2
3
), 62.9 (C-5), 65.2 (C-5 ),
0
0
0
2
), 69.1 (C-4 ), 72.7 (C-2 ), 72.8 (C-2), 73.5 (C-3 ), 75.5 (C-
ꢀ
1
0
(C
qAr), 175.0 (C¼O); IR (ATR, neat): 1598 cm (C¼O); elemental
3), 76.3 (C-4), 101.8 (C-1 ), 102.9 (C-1), 177.0 (C¼O); IR (ATR, neat):
ꢀ
1
analysis: calcd (%) for C29 51NO O: C 64.59, H 9.81, N 2.60;
H
7
þ0.75 H
2
1599 cm (C¼O); elemental analysis: calcd (%) for C28
H55NO11: C
found: C 64.48, H 10.32, N 2.89.
57.81, H 9.53, N 2.41; found: C 57.56, H 9.61, N 3.04.
2
0
ꢁ
20
IL 12. Yield 99%, white solid, [
a
]
D
¼ ꢀ24.5 (c ¼ 0.38 in DMSO);
IL 20. Yield 91%, white solid, m.p. 93 C, [
a
]
D
¼ ꢀ35.7 (c ¼ 0.34
3
1
ꢁ
1
ꢁ
H NMR (500 MHz, DMSO-d6, 25 C):
d
¼ 0.84e0.89 (12H, m,
in H
2
O); H NMR (600 MHz, D
2
O, 25 C):
d
¼ 0.88 (12H, t, J 7.0,
NCH
NCH
NCH
2
2
2
CH
CH
CH
2
CH
2
CH
CH
CH
2
CH
CH
CH
CH
2
CH
CH
CH
CH
3
),
),
1.26e1.30
1.52e1.57
(24H,
(8H,
m,
m,
NCH
NCH
NCH
2
2
2
CH
CH
2
2
CH
2
CH
CH
2
CH
CH
2
CH
CH
3
),
),
1.30e1.35
1.63e1.67
3.15e3.20
(24H,
(8H,
(8H,
m,
m,
m,
2
CH
2
2
2
3
CH
CH
CH
2
2
2
2
3
2
CH
2
2
2
3
), 3.01e3.08 (2H, m, 2-H, 5-H), 3.12e3.20
CH CH CH ), 3.29e3.36 (1H, m, 4-H),
CH
2
CH
CH
2
2
CH
CH
2
CH
3
),
3
7.8, 3
0
(
9H, m, 3-H, NCH
2
2
2
2
2
3
NCH
2
CH
2
2
3
2
CH
3
), 3.25 (1H, dd,
J
2
0
,1
0
J
2
0
,3
0
9.1, 2 -H),
3
2
2
0
3
.44 (3H, br s, OH), 3.73 (1H, dd, J5,4 5.3, J5,5 11.2, 5-H), 4.21 (1H, d,
3.30 (1H, t,
J
5
0
,4’
¼
J
5
0
,5
0
11.6, 5 -H), 3.34e3.39 (2H, m, 2-H, 5-H),
3
2
2
3
3
3
3
0
0 0
9.1, 3 -
3 ,4
J1,2 7.6, 1-H), 4.53 (1H, d, J 12.3, OCH
2
), 4.75 (1H, d, J 12.3, OCH
2
),
3.41 (1H, t, J3,2 ¼ J3,4 9.3 Hz, 3-H), 3.57 (1H, t, J
3
0
,2’ ¼ J
3
3
13
0
7
.25 (1H, d, J 8.1, CHAr), 7.80 (1H, d, J 8.1, CHAr); C NMR (125 MHz,
H), 3.60e3.65 (1H, m, 4 -H), 3.75e3.81 (1H, m, 4-H), 3.96 (1H, dd,
ꢁ
3
3
2
0
2
DMSO-d6, 25 C):
d
¼
13.8 (NCH
), 21.9 (NCH
), 30.6 (NCH
2
CH
CH
2
CH
CH
2
CH
CH
2
CH
CH
CH
), 69.8 (C-4), 73.5
2
CH
3
), 21.0
J
J
5
0
,4
0
5.4, J
5
0
,5
0
11.6, 5 -H), 4.05 (1H, d, J 15.6, OCH
2
), 4.07 (1H, dd,
2
2
3
(
(
(
(
NCH
NCH
NCH
2
CH
CH
CH
2
CH
CH
CH
2
2
2
CH
CH
CH
2
2
2
CH
CH
CH
2
2
2
CH
CH
CH
3
3
3
2
2
2
2
2
CH
3
), 25.5
5,4 5.2, J5,5 11.6, 5-H), 4.22 (1H, d, J 15.6, OCH
2
), 4.42 (1H, d, J1,2
3
0
13
CH
2
CH
2
CH
2
2
CH
3
), 57.7
7.7, 1-H), 4.44 (1H, d,
25
(NCH
(NCH
J
1
0
,2
0
7.8, 1 -H); C NMR (150 MHz, D O,
2
2
2
2
ꢁ
2
2
), 65.9 (C-5), 69.0 (OCH
2
C):
d
¼
13.2
(NCH
), 21.7 (NCH
), 30.3 (NCH
2
CH
CH
CH
2
CH
2
CH
CH CH
CH CH
2
CH
CH
CH
2
CH
CH
CH
3
),
20.9
), 25.1
3
), 58.1
C-2), 76.8 (C-3), 103.3 (C-1), 126.2 (CHAr), 128.9 (CHAr), 138.3 (CqAr),
39.7 (CqAr), 169.2 (C¼O); IR (ATR, neat): 1599 cm
2
CH
CH
2
2
CH
CH
2
CH
CH
2
CH
CH
2
CH
CH
3
3
2
2
2
2
2
2
3
ꢀ
1
1
(C¼O);
2
2
2
2
2
2
2
2

76
S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
0
7.7, 1-H); 13C NMR (125 MHz, D
ꢁ
(
(
(
NCH
2
CH
2
CH
2
CH
2
CH
2
CH
3
), 62.9 (C-5), 65.2 (C-5 ), 68.4 (OCH
2
), 69.1
2
O, 25 C):
d
¼ 14.6 (C(O)OCH
2 3
CH ),
0
0
0
C-4 ), 72.7 (C-2 ), 72.8 (C-2), 73.5 (C-3 ), 75.5 (C-3), 76.3 (C-4), 101.8
62.1 (C(O)OCH CH ), 65.2 (C-5), 66.3 (OCH ), 68.7 (C-4), 73.4 (C-2),
2
3
2
0
ꢀ1
C-1 ), 102.9 (C-1), 177.0 (C¼O); IR (ATR, neat): 1598 cm (C¼O);
75.2 (C-3), 103.6 (C-1), 173.9 (C¼O); IR (ATR, neat):
ꢀ1
: [MþNa]þ:
elemental analysis: calcd (%) for C36
2
H
71NO11: C 62.31, H 10.31, N
1745 cm (C¼O); ESI-HRMS: m/z calcd for C
9 7
H16NaO
.02; found: C 61.97, H 10.41, N, 2.32.
IL 21. Yield 99%, oily, [
259.0794; found: 259.0797.
2
0
1
Xyloside 18. 1.136 g, oily; 1H NMR (600 MHz, D
ꢁ
a
]
D
¼ ꢀ40.5 (c ¼ 0.35 in H
2
O); H NMR
2
O, 25 C):
ꢁ
3
3
0 0
(
500 MHz, D
2
O, 25 C):
d
¼ 0.92 (12H, t, J 7.3, PCH
7.2, PCH CH CH CH ), 1.49e1.57 (8H, m,
), 2.12e2.18 (8H, m, PCH
2
CH
2
CH
2
CH
3
),
d
¼ 1.31 (3H, t, J 7.2, C(O)OCH
2 3
CH ), 3.24e3.29 (2H, m, 2 -H, 5 -H),
3
0
0
1
PCH
dd,
3
.44 (8H, sext,
J
2
2
2
3
3.32e3.38 (3H, m, 2-H, 3-H, 5-H), 3.50e3.56 (2H, m, 3 -H, 4 -H),
3
2
0
CH
J
2
CH
2
CH
3
2
CH
2
CH
¼
2
CH
3
0
), 3.25 (1H,
11.6, 5 -H),
3.66e3.72 (1H, m, 4-H), 3.93 (1H, dd, J
5
0
,4
0
5.4, J
5
0
,5
0
11.6, 5 -H), 4.04
2
3
3
0
3
2
0
3
2
3
0
0
7.8,
J
0
0
9.1, 2 -H), 3.30 (1H, t,
J
5
0
J
0
(1H, dd, J5,4 5.2, J5,5 11.7, 5-H), 4.24 (2H, q, J 7.2, C(O)OCH
CH
);
),
C
2
,1
2
,3
,4’
5
,5
2
3
3
3
2
0
13
.35e3.40 (2H, m, 2-H, 5-H), 3.40 (1H, t, J3,2 ¼ J3,4 9.3, 3-H), 3.57
4.29 (1H, d, J 12.6, OCH
2
), 4.35e4.38 (3H, m, 1-H, 1 -H, OCH
2
3
3
0
0
ꢁ
(
(
1H, t,
J
3
0
,2’ ¼ J
3
0
,4
0
9.1, 3 -H), 3.60e3.64 (1H, m, 4 -H), 3.75e3.81
NMR (150 MHz, D
OCH CH
2
O, 25 C):
d
0
¼ 13.1 (C(O)OCH
2 3
CH ), 60.9 (C(O)
3
2
0
2
0
0
0
1H, m, 4-H), 3.95 (1H, dd, J
5
0
,4
0
5.4, J
5
0
,5
0
11.6, 5 -H), 4.04 (1H, d, J
2
3
), 63.1 (C-5), 65.4 (C-1 ), 65.7 (C-5), 69.6 (C-4 ), 72.9 (C-2 ),
3
2
2
0
1
OCH
5.6, OCH
2
), 4.06 (1H, dd, J5,4 5.3, J5,5 11.7, 5-H), 4.22 (1H, d, J 15.6,
73.0 (C-2), 74.0 (C-3 ), 76.2 (C-3), 76.6 (C-4),102.5 (C-1 ),103.2 (C-1),
3
3
0
13
ꢀ1
), 4.42 (1H, d,
J
1,2 7.7, 1-H), 4.44 (1H, d,
J
1
0
,2
0
7.8, 1 -H);
CH ), 17.6 (d, J
), 23.2 (d, J
), 69.1 (C-
C
170.7 (C¼O); IR (ATR, neat): 1736 cm (C¼O); ESI-HRMS: m/z calcd
2
ꢁ
þ
NMR (125 MHz, D
8.2, PCH CH CH
CH
2
O, 25 C):
d
¼ 12.5 (PCH
2
CH
2
CH
2
CH
3
for C14
H
24NaO11: [MþNa] : 391.1216; found: 391.1219.
4
1
4
1
d
2
2
2
CH
CH
3
), 22.7 (d, J 4.6, PCH
2
CH CH
2
2
3
0
5.3, PCH
2
CH
2
2
3
), 62.9 (C-5), 65.2 (C-5 ), 68.4 (OCH
), 72.7 (C-2 ), 72.8 (C-2), 73.5 (C-3 ), 75.5 (C-3), 76.3 (C-4),101.8 (C-
2
3. Results and discussion
0
0
0
0
31
ꢁ
),102.9 (C-1), 177.0 (C¼O); P NMR (202.4 MHz, D
2
O, 25 C, TMS):
3.1. Synthesis
ꢀ
1
¼ 33.23 (s; PBu ); IR (ATR, neat): 1601 cm (C¼O); elemental
4
analysis: calcd (%) for C28
found: C 55.37, H 9.15.
H
55
O11Pþ0.25 H
2
O: C 55.75, H 9.27;
The
b
-D-xyloside-based salts 5e13 were synthesized in four
-D-
steps from D-xylose (Scheme 2). First, 1,2,3,4-tetra-O-acetyl-
b
xylopyranose 1 was selectively prepared under kinetic control from
ꢁ
2
.3.3. “Click” reaction
Propargyl- -D-xyloside 15 (470 mg, 2.5 mmol) and ethyl 2-
azidoacetate (387 mg, 3 mmol) were dissolved in a mixture t-
butanol/water: 1/1 (4 mL). CuSO .5H O (45 mg, 0,18 mmol) and
D-xylose and sodium acetate in acetic anhydride at 100 C [32].
b
Freshly prepared peracetylated xylopyranose 1 was then treated
with either ethyl glycolate, methyl 6-hydroxyhexanoate [31] or
4
2
methyl 4-(hydroxymethyl)benzoate in the presence of BF
The prepared -D-xylosides were then deacetylated without
further purification under Zempl eꢀ n conditions [35] to give the
-D-
xylopyranosides 2e4 with free hydroxyl groups. Compounds 2 and
4 were isolated in a pure form with good overall yields over two
steps, respectively 72% and 70%, while 3 was obtained with a low
yield (26%) probably due to a lack of reactivity of the methyl 6-
hydroxyhexanoate towards the peracetylated xylopyranose 1 dur-
ing the glycosylation step. Alternative reaction conditions using 4
3 2
.Et O.
sodium ascorbate (100 mg, 0.5 mmol) were then added. After 12 h
stirring at room temperature, the reaction mixture was purified by
flash chromatography over silica gel (EtOAc/MeOH: 9/1). After
evaporation to dryness, compound 16 was obtained as a white
solid.
b
b
ꢁ
20
Xyloside 16. Yield 86%, white solid, m.p. 103 C, [
a
]
D
¼ ꢀ 43.4
1
ꢁ
3
(
c ¼ 0.35 in H
2
O); H NMR (500 MHz, D
2
O, 25 C):
d
¼ 1.28 (3H, t, J
7
.1, C(O)OCH
2
CH ), 3.26e3.35 (2H, m, 2-H, 5-H), 3.43 (1H, t,
3
3
3
3
J
3,2 ¼ J3,4 9.2, 3-H), 3.59e3.64 (1H, m, 4-H), 3.97 (1H, dd, J5,4 5.5,
3 2
equiv. of BF .Et O and 6-methylhexanoate or longer reaction times
2J5,5 11.6, 5-H), 4.28 (2H, q, J 7.1, C(O)OCH
3
3
didn't improve the yield.
2
3
CH ), 4.50 (1H, d, J1,2 7.8,
2
2
1
-H), 4.88 (1H, d, J 12.6, OCH
2
), 4.97 (1H, d, J 12.6, OCH
2
), 5.40 (2H,
O,
),
), 63.4 (C-5), 69.6 (C-4), 74.1 (C-2), 76.0 (C-3),
Compounds 2e4 were then mixed with either tetrabuty-
lammonium hydroxide (TBAOH), tetrahexylammonium hydroxide
(THAOH) or tetrabutylphosphonium hydroxide (TBPOH) in a 1:1
13
s, triazolyl-CH
2
6
2
), 8.12 (1H, s, H-triazolyl); C NMR (125 MHz, D
CH ), 28.5 (C(O)OCH CH ), 51.6 (OCH
2
2
ꢁ
5 C):
d
¼ 13.4 (C(O)OCH
2
3
2
3
ꢁ
2.4 (triazolyl-CH
2
stoichiometry in water for 1 h at 50 C to yield the corresponding
1
02.3 (C-1), 127.0 (C-H triazolyl), 143.2 (C-triazolyl), 169.2 (C¼O); IR
salts 5e13. Saponification reactions occurred in high yields in all
ꢀ1
1
13
(
ATR, neat): 1737 cm (C¼O); elemental analysis: calcd (%) for
cases (77e99%). H and C NMR spectra showed the total disap-
pearance of the signals of the methyl group of the ester function.
Furthermore, theoretical and experimental proportions in
elemental analyses appear to be consistent with an acceptable error
of less than 0.4% by taking into account in some cases the hydro-
philic nature of these molecules.
12 19 3 7
C H N O
: C 45.42, H 6.03, N 13.24; found: C 44.99, H 5.97, N
13.16.
2.3.4. Enzymatic transglycosylation reaction
Xylans (14 g, 10% p/v), ethyl glycolate (14 mL, 10% v/v), xylanase
1
0 IU/mL (50 mL) and water (76 mL) were introduced in a closed
The
b
-D-xyloside-based IL 14 containing a triazolyl linker was
-D-xyloside 15 (Scheme 3), as previ-
glass vessel with a magnetic stirring. The reaction was incubated in
a thermostated oil bath for 24 h at 60 C and stopped by incubating
during 10 min at 100 C. Then, the reaction mixture was centrifuged
synthesized from propargyl-
ously described [33]. First, a Huisgen-type 1,3 dipolar reaction
[36,37] catalyzed by Cu(I) species (CuAAC) [38e40] was applied in
b
ꢁ
ꢁ
for 10 min in order to pellet the residual xylans. The surnageant was
concentrated to dryness under reduced pressure and the residue,
extracted with a mixture EtOAc/MeOH (1:1) (3 ꢂ 140 mL). The
combined extracts were concentrated to dryness under reduced
pressure and the crude product was purified by flash chromatog-
raphy over silica gel (EtOAc/MeOH: 9:1) in order to isolate com-
pounds 17 and 18 in a pure form.
2
the presence of ethyl 2-azidoacetate in a mixture t-BuOH/H O (1/1)
to give the “click” compound 16 [41]. Direct purification by flash
chromatography (eluting mixture EtOAc/MeOH: 7/3) provided
compound 16 in a pure form with a good yield (86%). The presence
1
of the 1,2,3-triazolyl linkage was confirmed in H NMR spectra by
the signal at 8.12 ppm. FTIR spectrum shows the disappearance of
ꢀ
1
the band around 2110 cm suggesting that the excess of azide was
1
ꢁ
13
Xyloside 17. 815 mg, oily; H NMR (500 MHz, D
2
O, 25 C):
removed during the purification. The C NMR spectrum confirmed
3
3
2
d
¼ 1.30 (3H, t, J 7.2, C(O)OCH
2
CH
3
), 3.34 (1H, dd, J5,4 10.4, J5,5 11.6,
the 1,4-substitution of the triazole moiety by the large
azolyl
- dC-triazolyl) value of 16.2 ppm.
D(d
C-H tri-
3
3
3
3
5
3
4
-H), 3.39 (1H, dd, J2,1 7.7, J2,3 9.2, 2-H), 3.48 (1H, t, J3,2 ¼ J3,4 9.2,
3
2
-H), 3.65e3.70 (1H, m, 4-H), 4.00 (1H, dd, J5,4 5.5, J5,5 11.6, 5-H),
Compound 16 was then mixed with tetrabutylammonium hy-
3
3
ꢁ
.29 (2H, q, J 7.2, C(O)OCH
2
CH
3
), 4.45 (2H, s, OCH
2
), 4.49 (1H, d, J1,2
droxide (TBAOH) in a 1:1 stoichiometry in water for 1 h at 50 C to

S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
77
Scheme 2. Synthesis of the b-D-xyloside-based ILs 5e13.
Scheme 3. “Click” synthesis of the b-D-xyloside-based IL 14.
form the corresponding salt 14 in high yield (Scheme 3). ESI-HRMS
Using enzymatic transglycosylation with glycoside hydrolases to
indicates the presence of the corresponding anion, with a signal at
perform glycosylation reactions: i) avoids to proceed via chemical
route such as the well-known Fischer glycosidation [42] or the
Koenigs-Knorr reaction [43] that require organic solvents and acid
2
88.0826 (m/z) for 14 (corresponding chemical formula
).
C
10 14 3 7
H N O

78
S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
Scheme 4. Xylanase-catalyzed transglycosylation of xylans with ethyl glycolate.
catalysts, ii) minimizes waste, iii) favors the anomeric stereo-
selectivity and iv) can lead in the same time to oligoxylosides with a
degree of polymerization greater than one. Previous studies
demonstrated the ability of xylanases to produce xylosides and
oligoxylosides from xylans [18,32,33,44e48]. From beechwood
xylans and ethyl glycolate, the xylanase from Thermobacillus xyla-
balance (HLB) of the anionic part seems to partially influence the
physical properties at room temperature of the -D-xyloside- and
-D-xylobioside-based ILs. Indeed, -D-xyloside-based ILs 8 and 9
bearing a pentyl linker and 14 with a triazolyl linker are very
viscous liquids whereas 5 and 6 containing a methylene linker or 11
and 12 with a benzyl linker are solid compounds.
b
b
b
nilyticus, selectively produced
b
-D-xyloside 17 (58.2 mg per g of
Incorporating a benzyl linker instead of a methylene on the
anomeric position of the sugar leads to an increase of the solid-
liquid transitions, respectively at 98 C for 11 and 112 C for 12,
probably due to the presence of aromatic rings which allows p-p
xylans) and -D-xylobioside 18 (81.1 mg per g of xylans) in aqueous
b
ꢁ
ꢁ
media (Scheme 4).
To study the influence of the polar head on the physico-chemical
properties of the corresponding salts,
b
-D-xylobioside-based ILs
stacking between ions and results in an increase of the lattice
energy.
1
9e21 were synthesized from -D-xylobioside 18 via a saponifi-
b
cation reaction in the presence of either tetrabutylammonium hy-
droxide (TBAOH), tetrahexylammonium hydroxide (THAOH) or
tetrabutylphosphonium hydroxide (TBPOH) in a 1:1 stoichiometry
However, increasing the number of xylose units from 1 to 2 does
not result in a significant change in the physical state, since com-
pounds 19, 20, 21 and their parent compounds 5, 6, 7 follow the
same trend. Only a slight increase of the melting temperature from
72 C to 93 C in the tetrahexylammonium series (6 / 20) by
increasing the number of xylose units from 1 to 2 is observed.
The thermogravimetric analyses show that the decomposition
(
Scheme 5). These salts were isolated in high yields (91e99%) and
1
13
ꢁ
ꢁ
characterized by H and C NMR spectra, and elemental analyses.
All the prepared ILs are highly soluble in water and methanol
and very poorly soluble in classical organic solvents such as
dichloromethane, chloroform, diethyl ether or ethyl acetate.
temperatures of the b-D-xyloside- and b-D-xylobioside-based ILs
ꢁ
ꢁ
are included between 140 C and 260 C. The thermal stability of
these ILs seems to be limited likely due to the strength of
heteroatom-carbon and heteroatom-hydrogen bonds [53]. As ex-
pected, the phosphonium derivatives have higher thermal stability
than their ammonium analogs [54]. Likewise, increasing the
number of xylose units from 1 to 2 enhances the decomposition
temperature. However, no trend was observed for a same linker,
changing the size of the alkyl chain from butyl to hexyl in the
ammonium series.
3.2. Physicochemical properties
Table 1 gives some of their physicochemical properties. Glass
transition (T ) and decomposition (Tdec) temperatures were evalu-
g
ated by differential scanning calorimetry (DSC) and thermal
gravimetric analysis (ATG) experiments.
All the phosphonium salts 7, 10, 13 and 21 are extremely viscous
liquids at room temperature whereas most of the corresponding
ammonium salts 5, 6, 11, 12, 19 and 20 are solids. A few studies have
previously described that the replacement of the nitrogen atom by
the phosphorus one, lowers the melting points of the phosphonium
salts in comparison to their ammonium analogs [49e51]. This
decrease might be attributed to a larger radius of the phosphorus
atom compared to the nitrogen atom, which decreases the lattice
energy and gives more flexibility to the cation structure.
The glass transition temperatures, which indicate the lower
limit for the salts 7, 8, 9, 10, 13, 14 and 21 in which they can be used
as liquid if no melting point is determined, are generally included
ꢁ
ꢁ
between ꢀ35 C and 2 C. Negative T
g
values are classical for ionic
liquids [51].
4. Conclusions
Surprisingly, for a same linker, changing the size of the alkyl
chain from butyl to hexyl in the ammonium series brings a slight
increase to the melting temperatures measured for these ILs [3].
In conclusion, a chemical and a chemo-enzymatic route enabled
the easy preparation of -D-xyloside- and -D-xylobioside-based
ILs containing either tetraalkylphosphonium or tetraalkylammo-
nium cations with a modular amphiphilic anionic structure. The
HLB of each IL anion is designed by introducing one or two xylose
b
b
ꢁ
ꢁ
Thus, the melting points for 5 and 6 are respectively 59 C and 74 C
ꢁ
ꢁ
and for 11 and 12, respectively 98 C and 112 C.
In addition to the nature of the cation, the hydrophilic lipophilic
Scheme 5. Synthesis of the
b-D-xylobioside-based ILs 19e21.

S. Gatard et al. / Carbohydrate Research 451 (2017) 72e80
79
Table 1
Properties of
b
-D-xyloside- and b-D-xylobioside-based ILs.
mpa ( C) [52]
ꢁ
T
b
( C)
ꢁ
[a
]
20
Physical aspect
Compound
O
g
O
O
R
R
R
R
HO
HO
O
HO
O
LINKER
Y
OH
OH
O
n
n
0
Linker
Y, R
5
6
7
N, n-Bu
59
74
e
e
ꢀ25.7
ꢀ15.1
ꢀ25.3
Solid
Solid
Oil
0
0
N, n-Hex
P, n-Bu
ꢀ4
e
8
9
0
0
0
N, n-Bu
N, n-Hex
P, n-Bu
e
e
e
ꢀ35
ꢀ30
0
ꢀ22.6
ꢀ15.1
ꢀ20.1
Oil
Oil
Oil
1
0
1
1
0
0
0
N, n-Bu
N, n-Hex
P, n-Bu
98
112
e
ꢀ32
ꢀ4
ꢀ24.3
ꢀ24.5
ꢀ28.9
Solid
Solid
Oil
1
1
2
3
ꢀ19
14
0
N, n-Bu
e
ꢀ26
ꢀ23.9
Oil
N
N
N
19
20
21
1
1
1
N, n-Bu
N, n-Hex
P, n-Bu
e
ꢀ32
16
2
ꢀ39.0
ꢀ35.7
ꢀ40.5
Solid
Solid
Oil
93
e
a
Determined on a Stuart™ melting point apparatus SMP3.
Determined by DSC.
b
units and various hydrophobic moieties (methylene, pentyl, benzyl
or triazolyl) into the anomeric position bearing a carboxylate group.
ILs containing phosphonium cations and a pentyl moiety are
generally liquids while those containing ammonium cations and a
small alkyl or benzyl moiety are solids. The glass transition tem-
203e208.
7] H. Ohno (Ed.), Electrochemical Aspects of Ionic Liquids, second ed., John Wiley
Sons, Hoboken, N.J., U.S.A, 2011.
8] M.H. Chakrabarti, F.S. Mjalli, I.M. Alnashef, M.A. Hashim, M.A. Hussain,
L. Bahadori, C.T.J. Low, Renew. Sust. Energ. Rev. 30 (2014) 254e270.
[
[
[
&
9] D. Ma, Y. Tan, J. Ming, G. Zhao, J. Chin. Cereals Oils Assoc. 28 (2013) 124e128.
[
[
10] J. Song, H. Fan, J. Ma, B. Han, Green Chem. 15 (2013) 2619e2635.
11] P.T. Anastas, J.C. Warner, Green Chemistry: Theory and Practice, Oxford Uni-
versity Press, New York, 1998.
ꢁ
peratures for the liquids are between ꢀ35 and 0 C, and the tran-
sition melting temperatures for the solids are generally lower than
ꢁ
[12] J. Hulsbosch, D.E. De Vos, K. Binnemans, R. Ameloot, ACS Sustain. Chem. Eng. 4
2016) 2917e2931.
13] B. Kamm, R. Kamm, Adv. Biochem. Engin./Biotechnol. 105 (2007) 175e204.
[14] J.J. Bozell, G.R. Petersen, Green Chem. 12 (2010) 539e554.
1
00 C. In addition, the thermal stability of the phosphonium ILs is
(
higher than their ammoniums analogs. These results illustrate the
impact of the various anion/cation combinations on the thermal
properties of these biomass-derived ILs.
[
[
15] M. Sekine, T. Kimura, Y. Katayama, D. Takahashi, K. Toshima, RSC Adv. 3
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(
[
Acknowledgements
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ILs (M eꢀ lanie Gray, Maxime Moreaux, François Pedinielli, Aur eꢀ lien
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