Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-d-arabino-hexopyranosides

Article abstract of DOI:10.1016/j.chemphyslip.2008.07.008

A homologous series of alkyl 2-deoxy-α-d-arabino-hexopyranosides and alkyl 2-deoxy-β-d-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C₈ to C₁₈ alkanols) with ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the β-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the α-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the α- and β-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited mesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase.

Full text of DOI:10.1016/j.chemphyslip.2008.07.008

Chemistry and Physics of Lipids 155 (2008) 90–97
Contents lists available at ScienceDirect
Chemistry and Physics of Lipids
journal homepage: www.elsevier.com/locate/chemphyslip
Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides:
synthesis and thermotropic behavior of alkyl
2-deoxy-d-arabino-hexopyranosides
Madan Kumar Singha, Narayanaswamy Jayaramana,∗, D.S. Shankar Raob, S. Krishna Prasadb
a Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India
b Centre for Liquid Crystal Research, Jalahalli, Bangalore 560 013, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 April 2008
Received in revised form 20 June 2008
Accepted 11 July 2008
Available online 23 July 2008
A homologous series of alkyl 2-deoxy-␣-d-arabino-hexopyranosides and alkyl 2-deoxy-␤-d-arabino-
hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C8 to C18 alkanols) with
ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-hexopyranoside, followed by a deprotection. The ther-
motropic behavior of these new types of alkyl glycosides was investigated. It was observed that the
␤-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting
monotropic smectic A phase. In contrast, the ␣-anomers are all non-mesomorphic. An effort to identify
the liquid crystalline behavior of binary mixtures of the ␣- and ␤-anomers was undertaken and it was
found that mixtures containing equimolar amounts of the anomers exhibited mesomorphic behavior. A
fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be
important for the alkyl 2-deoxy glycosides to form the mesophase.
Keywords:
2-Deoxy glycosides
Glycolipids
Glycosylations
Liquid crystals
Mesophase behavior
Smectic A phase
© 2008 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
Hexdecyl ␤-d-glucopyranoside is an early example of the glycol-
ipids exhibiting liquid crystalline properties (Fischer and Helferich,
Amphiphilic sugars are known to exhibit liquid crystalline
behavior owing to their amhiphilicity (van Doren et al., 2000;
Vill and Hashim, 2002; Jeffrey, 1986; Paleos and Tsiourvas, 1995;
Goodby et al., 1998, 2007; Tschierske, 1998). Cell membrane bound
glycolipids are examples par excellence of the lyotropic behavior
of the amphiphilic sugars and their importance in biological func-
tions (Abraham and Pascher, 1997; Wolken and Brown, 1980). A
driving force for the mesophase formation in these molecules is
the phase segregation, leading to aggregates, possessing distinct
lipophilic and hydrophilic regions (Boullanger, 1997; van Doren and
Wingert, 1994). Amphiphilic sugars possess an abundance of chiral
centers and their liquid crystalline phases are generally smectic or
columnar and/or cubic phases (Molinier et al., 2003, 2006, 2007).
The absence of macroscopic chirality in the amphiphilic sugars and
glycolipids could be attributed to the strong hydrogen bonding net-
work between the hydroxyl groups of the sugar moiety, which force
a layering with head to head arrangement of the molecules. It was
shown recently that features that affect hydrogen bonding net-
work can lead to the formation of chiral mesophases in sugar-based
bolaamphiphiles (Abraham et al., 2005; Das et al., 2008).
1911; Noller and Rockwell, 1938). The homologous series of
both alkyl ␣-d-glucopyranosides and alkyl ␤-d-glucopyranosides
exhibit the smectic A (SmA) phase and the SmA to isotropic tran-
sition temperature increases with increasing alkyl chain length
(Goodby, 1984; Pfeffer et al., 1976; Jeffrey and Bhattacharjee, 1983).
With detailed information available currently on the mesomor-
phic behavior of only the normal alkyl glycosides, it is pertinent to
investigate the mesomorphic behavior on alkyl glycosides that lack
one or more hydroxyl group in their hydrophilic sugar component.
This report presents the results of the studies on alkyl glycosides,
wherein 2-deoxy sugar constitutes the hydrophilic segment. Sev-
eral homologues of the alkyl ␣-d-arabino-hexopyranosides and
alkyl ␤-d-arabino-hexopyranosides series are synthesized and the
thermotropic behavior of these new alkyl glycosides is assessed
with the aid of polarizing optical microscopy (POM) and differential
scanning calorimetry (DSC).
2. Results and discussion
2.1. Synthesis
The synthesis of alkyl 2-deoxyglucosides was initiated from
ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-hexopyranoside
(Paul and Jayaraman, 2004). The alkyl 2-deoxyglucosides were
∗
Corresponding author. Tel.: +91 80 2293 2406; fax: +91 80 2360 0529.
E-mail address: jayaraman@orgchem.iisc.ernet.in (N. Jayaraman).
0009-3084/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.chemphyslip.2008.07.008

M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
91
Scheme 1. Synthesis of alkyl 2-deoxy-d-arabino-hexopyranosides (Cn-2d-␣/␤-Glc).
prepared by the glycosylation of 1-alkanols with the above glycosyl
donor in the presence of N-iodosuccinimide (NIS)/trimethylsilyl
trifluoro-methanesulfonate (TMSOTf), followed by the deprotec-
tion of the acetate protecting groups (Scheme 1). The glycosylation
led to almost equal amounts of both the ␣- and the ␤-anomers. The
alkyl 2-deoxy-␣- and ␤-d-arabino-hexopyranosides (Cn-2d-␣-Glc
and Cn-2d-␤-Glc) were characterized by physical methods to
confirm their constitutions.
exhibited a monotropic SmA phase. Upon slow cooling from the
isotropic state, a fan-shaped texture was observed (Fig. 1). When
the sample exhibiting the undisturbed fan-shaped focal conic pat-
tern was pressed, a near complete homeotropic alignment was
observed, thereby suggesting the texture to be a SmA phase. The
observed SmA texture is seen commonly for the sugar meso-
gens (Gray and Goodby, 1984; Zur et al., 1998; Jayaraman et al.,
2007). The compounds C9-2d-␤-Glc, C11 -2d-␤-Glc and C13-2d-␤-
Glc exhibited an endothermic peak in the heating cycle and two
exothermic peaks in the cooling cycle. The higher temperature peak
corresponded to the I–SmA transition, whereas the low tempera-
ture peak in the cooling cycle was due to the SmA–Cr transition.
A representative DSC thermogram is shown in Fig. 2. The even
numbered compounds C10-2d-␤-Glc, C12-2d-␤-Glc and C14 -2d-␤-
2.2. Thermal behavior
The mesomorphic behavior of these new alkyl glycosides was
investigated by POM and DSC techniques. Among the alkyl 2-
deoxy-␤-glucosides (Cn-2d-␤-Glc), compounds C9–C14 (n = 9–14)
Fig. 1. The fan-shaped texture of the SmA phase obtained upon slow cooling of the isotropic liquid of C13 -2d-␤-Glc (left) and binary mixture C12 -2d-␣,␤-Glc (1:1) (right).

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M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
Table 2
Transition temperatures and enthalpies of transitions for the binary mixtures of
alkyl 2-deoxy-␣/␤-d-arabino-hexopyranosidesa
Binary mixtures
Transition temperature (◦C) [enthalpy (J/g)]
Cr 80.0 [131.3]b SmA 87.2 I 72.4 [5.3] SmA 39.1 [79.1] Cr
C9-2d-␣,␤-Glc (1:1)
C10 -2d-␣,␤-Glc (1:1) Cr 83.7 [136.8]b SmA 93.7 I 82.3 [5.9] SmA 46.9 [102.4] Cr
C11 -2d-␣,␤-Glc (1:1) Cr 86.2 [113.6]b SmA 94.5 I 86.2 [4.6] SmA 58.9 [97.1] Cr
C12 -2d-␣,␤-Glc (1:1) Cr 88.4 [107.6]b SmA 97.3 I 85.0 [4.0] SmA 56.8 [91.0] Cr
C13 -2d-␣,␤-Glc (1:1) Cr 93.1 [137.1]b SmA 95.2 I 94.0 [4.2] SmA 68.6 [128.1] Cr
C
C
C
C
C
14 -2d-␣,␤-Glc (1:1) Cr 94.9 [138.4]b SmA 102.6 I 92.0 [3.7] SmA 73.5 [133.2] Cr
15 -2d-␣,␤-Glc (1:1) Cr 95.7 [125.5]b SmA 104.6 I 92.3 [3.0] SmA 76.7 [120.8] Cr
16 -2d-␣,␤-Glc (1:1) Cr 98.5 [160.2]b SmA 105.5 I 94.1 [2.8] SmA 77.9 [140.8] Cr
17 -2d-␣,␤-Glc (1:1) Cr 100.4 [145.8]b SmA 106.5 I 92.1 [2.4] SmA 81.0 [142.5] Cr
18 -2d-␣,␤-Glc (1:1) Cr 102.1 [169.1]b SmA 106.7 I 93.2 [2.3] SmA 81.7 [146.3] Cr
a
The heating and cooling rate is 5 ◦C min−1, during the second cycle.
The Cr–SmA and SmA–I transitions are merging together. The enthalpies are
b
given for the combined transitions.
Fig. 2. DSC thermogram for C11 -2d-␣-Glc at a heating and cooling rate is 5 ◦C min−1
during the second cycle.
Fig. 1. The phase transition temperatures and associated enthalpies
are presented in Table 2. The thermograms of all the binary mix-
tures showed an endothermic peak followed by a weaker transition
in the heating cycle of the thermograms, perhaps suggesting the
appearance of the SmA phase, a feature that could not be, however,
confirmed in the polarizing microscopy observations. In the cool-
ing cycle of the thermogram, two exothermic peaks were observed.
The peak with lower enthalpy was due to I–SmA transition and
the peak with higher enthalpy corresponded to SmA–Cr transi-
tion. The DSC thermogram of C15-2d-␣,␤-Glc (1:1), obtained at a
rate of 5 ◦C min−1, is shown in Fig. 3. It is observed that while the
I–SmA phase transition temperature was weakly affected by the
rate of cooling, the crystallization (SmA–Cr) temperature showed
a very strong dependence. Fig. 4 shows the temperatures for the
transitions I–SmA and SmA–Cr phases as a function of the cooling
rate. The crystallization temperature reached a limiting value at a
cooling rate of ∼15 ◦C min−1. A similar dependence of the SmA–Cr
transition temperature on the cooling rate was reported for the
monotropic liquid crystalline polyester (Bashir et al., 1998).
The crystal structure of the binary mixtures of octyl ␣-d-
glucoside and octyl ␤-d-glucoside in equimolar ratio is known
previously (Jeffrey and Yeon, 1992). In the crystalline state, both the
␣- and ␤-derivatives arrange in an alternate fashion. A similar pos-
sibility could be considered with the binary mixtures of the 2-deoxy
glycosides. The mesomorphism of the binary mixtures could be due
to the formation of dimers of the ␣- and ␤-anomers. The thermal
behavior of the binary mixtures of C13-2d-␣-Glc and C13-2d-␤-Glc,
as well as C15-2d-␣-Glc and C15-2d-␤-Glc, in different molar ratios,
from 10 mol% to 90 mol%, was also investigated. As the amount of
Glc also exhibited a fan-shaped texture of SmA phase for a narrow
temperature range (<2 ◦C), immediately prior to the crystallization.
Perhaps this low thermal stability of the phase prevented its sig-
nature being seen in the DSC. The metastable nature of the SmA
phase was evident from the fact that the phase was monotropic
for the odd numbered homologues. Also, the mesophase of odd
chain length compounds were more stable than the even chain
length derivatives. It is important to note that the melting and the
isotropic to SmA transition temperatures do not seem to have a sys-
tematic variation with the alkyl chain lengths. The corresponding
␣-anomers, namely, alkyl 2-deoxy-␣-d-glucosides (Cn-2d-␣-Glc)
were all non-mesomorphic. The phase transition temperatures and
the associated enthalpies are presented in Table 1. The melting
points of the ␣-anomers are slightly more than the corresponding
␤-anomers.
The binary mixtures of alkyl 2-deoxy-␣-d-glucosides and alkyl
2-deoxy-␤-d-glucosides in equimolar ratio exhibited SmA phase,
similar to that of the pure ␤-derivatives in the cooling cycle. The
texture of SmA phase for C12-2d-␣,␤-Glc (1:1) is presented in
Table 1
Transition temperatures and enthalpies of transitions for alkyl 2-deoxy-␣/␤-d-
arabino-hexopyranosidesa
Compounds
Transition temperature (◦C) [enthalpy (J/g)]
C8-2d-␣-Glc
C8-2d-␤-Glc
C9-2d-␣-Glc
C9-2d-␤-Glc
Cr 107.9 [132.1] I 95.7 [131.7] Cr
Cr 83.1 [80.6] I 71.5 [80.4] Cr
Cr 104.3 [114.4] I 90.9 [113.5] Cr
Cr 91.9 [97.0] I 83.9 [5.2] SmA 72.11 [91.3] Cr
Cr 111.4 [160.7] I 100.3 [160.6] Cr
Cr 97.7 [118.1] I 88.1 SmA 86.5 [118.0] Crb
Cr 109.0 [174.8] I 82.7 [172.9] Cr
Cr 99.2 [87.0] I 93.8 [3.9] SmA 86.5[82.5] Cr
Cr 110.4 [153.5] I 96.4 [148.7] Cr
Cr 103.7 [148.4] I 99.5 SmA 97.6 [147.6] Crb
Cr 113.2 [181.8] I 98.2 [181.6] Cr
C10 -2d-␣-Glc
C10 -2d-␤-Glc
C11 -2d-␣-Glc
C11 -2d-␤-Glc
C12 -2d-␣-Glc
C12 -2d-␤-Glc
C13 -2d-␣-Glc
C13 -2d-␤-Glc
C14 -2d-␣-Glc
C14 -2d-␤-Glc
Cr 104.0 [125.6] I 98.9 [3.7] SmA 91.4 [120.6] Cr
Cr 113.6 [158.5] I 93.1 [150.1] Cr
Cr 106.1 [123.6] I 97.2 SmA 92.4 [119.0] Crb
Cr 116.3 [190.3] I 102.2 [181.9] Cr
Cr 108.4 [123.4] I 97.1 [121.4] Cr
C15 -2d-␣-Glc
C15 -2d-␤-Glc
C16 -2d-␣-Glc
C16 -2d-␤-Glc
C17 -2d-␣-Glc
C17 -2d-␤-Glc
C18 -2d-␣-Glc
Cr 117.0 [181.9] I 100.2 [181.3 Cr
Cr 109.2 [146.5] I 99.1 [137.9] Cr
Cr 117.9 [157.4] I 103.7 [157.3] Cr
Cr 111.3 [131.3] I 104.2 [127.1] Cr
Cr 119.0 [212.0] I 92.3 [209.1] Cr
Cr 110.2 [145.0] I 100.9 [136.6] Cr
C18 -2d-␤-Glc
a
The heating/cooling rate is 5 ◦C min−1, during the second cycle.
Both the I–SmA and SmA–Cr transitions merged together. The I–SmA transition
b
Fig. 3. DSC thermogram for C15 -2d-␣,␤-Glc (1:1), at a heating and cooling rate is
5
◦C min−1 during the second cycle.
temperature was determined with the aid of POM.

M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
93
The binary mixtures of the glycoglycerolipids with phospholipids
have been studied to determine the glycolipid–phospholipid mis-
cibility in the solid and liquid crystalline states (Koynova et al.,
1988). Also, the head group orientations of alkyl glycolipids at a
lipid bilayer interface have been studied in detail (Sanders and
Prestegard, 1992).
The liquid crystalline behavior of the normal alkyl glucosides
is well known (Goodby, 1984; Pfeffer et al., 1976; Jeffrey and
Bhattacharjee, 1983). The alkyl glucosides, in both the ␣- and the
␤-anomeric configurations, exhibit enantiotropic SmA phase, with
alkyl chain lengths from C7 to C16 . In this case, the SmA–I transi-
tion temperature increases with increasing alkyl chain length (Vill
et al., 1989). The clearing points of ␣-glucosides are also found to
be more than the corresponding ␤-anomers and the mesomorphic
range of ␣-anomers is more generally (Goodby et al., 2007). The dif-
ference between the alkyl glucosides and the compounds studied
herein is the absence of the hydroxyl group at C-2 of the sugar moi-
ety in the later. The mesomorphism in carbohydrates is primarily
due to the microphase segregation of hydrophilic and hydropho-
bic moieties (Boullanger, 1997; van Doren and Wingert, 1994). The
molecules form a bilayer structure, as the hydrophilic sugar head
groups held together by the strong hydrogen bonding, and the
hydrophobic alkyl chain tails by the weak van der Waals forces (van
Doren and Wingert, 1991). The crystal structure of the alkyl ␣-d-
glucoside reveals that the molecules form a bilayer structure, both
in the crystalline state as well as in the mesophase (Moews and
Knox, 1976; Jeffrey and Yeon, 1987; van Koningsveld et al., 1988;
Adasch et al., 1998; Hoffmann et al., 2000). The alkyl 2-deoxy glu-
cosides studied herein are devoid of the hydroxyl group at C-2.
The observation that the mesomorphism exists not only in short
temperature ranges, but also is dependent on the anomeric config-
uration can be accounted due to the absence of the hydroxyl group
at C-2 in these alkyl 2-deoxy glucosides. These observations are
in contrast to the mesophase behavior of normal alkyl glycosides
that show greater mesophase stabilities for the ␣-anomers. The ␣-
anomers of the alkyl 2-deoxy glycosides studied herein destabilize
the mesophase formation, either due to an extremely narrow tem-
perature range at which the mesophase evolves, or due to an altered
molecular arrangement, which does not allow the mesophase for-
mation. The fact that the binary mixtures of the ␣- and ␤-anomers
exhibit the SmA phase indicate a possible reduction in the melting
temperatures and the crystallization tendencies of the ␣-anomers,
so as to allow the smectic phase formation in the binary mixtures.
A number of examples can be seen wherein an induced mesophase
evolves in the binary mixtures, including glycolipids (Tschierske,
1998, 2001; von Minden et al., 2002; Paleos and Tsiourvas, 1995).
Fig. 4. Plot of transition temperature versus cooling rate for C11 -2d-␤-Glc.
the ␣-anomer increased in the pure ␤-anomer for C13-2d-Glc, the
mesophase range increased and it reached a maximum at 50 mol%.
Further increase in the ␣-component reduced the mesophase range
and above 80 mol%, the mesophase ceased to exist. For C15-2d-Glc,
where both ␣- and ␤-anomers were not liquid crystalline, 25 mol%
of ␣-anomer induced a mesomorphism in the pure ␤-anomer. As
the component of the ␣-anomer increased, the mesomorphic range
increased, with a maximum at 50 mol%. The corresponding phase
diagrams are presented in Fig. 5. At higher concentrations of the ␣-
anomer, the mesomorphic range decreased. These results show that
both the ␣- and the ␤-anomers are able to induce the mesomor-
phism in the counterpart anomer equally. Importantly, the results
suggest that not only the hydroxyl group of the sugar moiety, but
also the anomeric configuration plays a role in the mesophase for-
mation.
There are few reports on the mesomorphic behavior of the
binary mixtures of thermotropic carbohydrate mesogens. The
binary mixtures of the ␣- and the ␤-anomers of n-alkyl d-
glucopyranosides were studied to describe the molecular packing
and co-solubility in the crystalline and the liquid crystalline phases
(Dorset, 1990). A cubic phase could be induced in the binary mix-
ture, with one component forming the columnar phase in its pure
state and the other component forming the lamellar phase (von
Minden et al., 2002; Feng et al., 2003). The stability of the induced
cubic phase was temperature- as well as concentration-dependent.
Fig. 5. Phase diagrams for the binary mixtures of (a) C13 -2d-␣-Glc and C13 -2d-␤-Glc and (b) C15 -2d-␣-Glc and C15 -2d-␤ –Glc.

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M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
3. Conclusion
4.2.1. Octyl 2-deoxy-˛-d-arabino-hexopyranoside (C8-2d-˛-Glc)
[˛]D25 = 106.4 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı:
4.86 (d, 1H, J = 5.01 Hz, –OH), 4.74 (d, 1H, J = 5.01, H-1), 4.73 (d, 1H,
J = 4.80 Hz, –OH), 4.40 (t, 1H, J = 5.90 Hz, –OH), 3.61 (m, 1H, H-3), 3.52
(m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24 (m, 1H,
H-5), 3.02 (m, 1H, J = 5.01 Hz, H-4), 1.85 (dd, 1H, J = 12.84, J = 5.01 Hz,
H-2e), 1.47 (m, 2H, –CH2–), 1.41 (dd, 1H, J = 12.84, J = 3.48 Hz, H-
2a), 1.22 (bs, 10H, –CH2–), 0.84 (t, 3H, J = 6.94 Hz, –CH3). 13C NMR
(75 MHz, DMSO-d6) ı: 96.4, 73.0, 71.7, 68.0, 66.0, 61.0, 38.0, 31.2,
28.9, 28.8, 28.7, 25.8, 22.1, 13.9. ESI-MS: m/z calcd for C14 H28O5Na:
299.1834; found: 299.1836. Anal. calcd for C14 H28O5: C, 60.84; H,
10.21; found: C, 60.65; H, 9.83%.
A
new homologous series of alkyl 2-deoxy-d-arabino-
hexopyranosides, in pure ␣- and ␤-anomeric forms, is synthesized.
Only the ␤-anomers with alkyl chain lengths between C9 and
C14 exhibited a monotropic SmA phase. None of the ␣-anomer
was liquid crystalline. Mesophase could, however, be induced by
mixing either of the anomers of same alkyl chain lengths and the
mesophase range was found to reach a maximum at ∼50 mol%.
In particular, this study uncovers that the presence of the C-2
hydroxyl group is crucial for the normal alkyl glycosides to exhibit
mesophase in a wide temperature range, for both the anomeric
forms of the glycosides. The absence of the C-2 hydroxyl group in
the present alkyl glycosides restricted their thermotropic behavior.
The present study illustrates that the C-2 hydroxyl group plays a
significant role in the mesophase formation of alkyl glycosides.
4.2.2. Octyl 2-deoxy-ˇ-d-arabino-hexopyranoside (C8-2d-ˇ-Glc)
[˛]D25 = −22.5 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(t, 2H, J = 4.54 Hz, –OH), 4.44 (t, 1H, J = 5.90 Hz, –OH), 4.41 (dd, 1H,
J = 9.71, 1.45 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.65 (ddd, 1H, J = 12.10,
5.90, 1.71 Hz, H-3), 3.44 (m, 1H, J = 5.90 Hz, H-4), 3.34 (m, 2H, H-6a
and H-6b, overlapped with DMSO residue peak), 2.99 (m, 1H, H-5),
1.91 (ddd, 1H, J = 12.10, 4.94, 1.45 Hz, H-2e), 1.46 (m, 2H, J = 6.03 Hz,
–CH2), 1.23 (m, 11H, H-2a and methylene), 0.84 (t, 3H, J = 6.52 Hz,
–CH3). 13C NMR (75 MHz, CDCl3) ı: 100.1, 75.4, 71.8, 71.5, 69.9, 61.9,
38.8, 31.8, 29.6, 29.4, 29.3, 26.0, 22.7, 14.1. ESI-MS: m/z calcd for
4. Experimental
4.1. General
Chemicals were purchased from commercial sources and were
used without further purification. The following alkyl 2-deoxy
glycosides are known previously: octyl 2-deoxy-␣/␤-d-arabino-
hexopyranoside (Liu and Still, 1993; Kim et al., 2005); tetradecyl
2-deoxy-␣/␤-d-arabino-hexopyranoside (Sanders and Prestegard,
1992). Solvents were dried and distilled using literature proce-
dure (Perrin and Armarego, 1988). Analytical TLC was performed on
commercial Merck plates, coated with silica gel GF254 (0.25 mm),
with a detection by charring after immersion in 5% H2SO4/EtOH.
Silica gel (100–200 mesh) was used for column chromatography.
Microanalyses were performed on an automated C, H, N ana-
lyzer. High resolution mass spectra were obtained from Q-TOF
instruments by an electrospray ionization (ESI) technique. 1H and
13C NMR spectral analysis were performed on a Jeol 300 and
75 MHz, respectively, or a Bruker 400 and 100 MHz, respectively.
The mesophases were characterized by using a Mettler FP82HT
hot stage and central processor, in conjunction with a Litz DMRXP
polarizing microscope. The transition temperatures and transition
enthalpies were determined by differential scanning calorimetry
(DSC Q100, TA Instruments).
C14 H28O5Na: 299.1834; found: 299.1825. Anal. calcd for C14 H28O5:
C, 60.84; H, 10.21; found: C, 60.76; H, 10.16%.
4.2.3. Nonyl 2-deoxy-˛-d-arabino-hexopyranoside (C9-2d-˛-Glc)
[˛]D25 = 96.7 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(d, 1H, J = 5.04 Hz, –OH), 4.76 (d, 1H, J = 5.04 Hz, H-1), 4.73 (d, 1H,
J = 4.84 Hz, –OH), 4.41 (t, 1H, J = 5.86 Hz, –OH), 3.60 (m, 1H, H-3), 3.52
(m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24 (m, 1H,
H-5), 3.01 (m, 1H, J = 5.04, H-4), 1.86 (dd, 1H, J = 12.85, 5.04 Hz, H-
2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.85, 3.53 Hz, H-2a), 1.23
(bs, 12H, –CH2), 0.84 (t, 3H, J = 6.41 Hz, –CH3). 13C NMR (100 MHz,
DMSO-d6) ı: 96.4, 73.1, 71.7, 68.1, 66.1, 61.0, 38.0, 31.3, 29.1, 29.0,
28.9, 28.7, 25.8, 22.1, 14.0. ESI-MS: m/z calcd for C15H30O5Na:
313.1978; found: 313.1990. Anal. calcd for C15H30O5: C, 62.04; H,
10.41; found: C, 61.92; H, 10.16%.
4.2.4. Nonyl 2-deoxy-ˇ-d-arabino-hexopyranoside (C9-2d-ˇ-Glc)
[˛]D25 = −28.3 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı:
4.84 (t, 2H, J = 4.49 Hz, –OH), 4.45 (t, 1H, J = 5.91 Hz, –OH), 4.41
(dd, 1H, J = 9.62, 1.42 Hz, H-1), 3.73 (m, 2H, –OCH2), 3.66 (ddd, 1H,
J = 12.0, 5.91, 1.86 Hz, H-3), 3.45 (m, 1H, J = 5.91 Hz, H-4), 3.35 (m,
2H, H-6a and H-6b, overlapped with DMSO residue peak), 3.00
(m, 1H, H-5), 1.92 (ddd, 1H, J = 12.0, 4.85, 1.42 Hz, H-2e), 1.46 (m,
2H, J = 5.81 Hz, –CH2), 1.23 (m, 13H, H-2a and methylene), 0.84 (t,
3H, J = 6.26 Hz, –CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0,
71.6, 70.7, 68.1, 61.2, 38.9, 31.3, 29.2, 29.0, 28.9, 28.7, 25.6, 22.1,
14.0. ESI-MS: m/z calcd for C15H30O5Na: 313.1991; found: 313.1990.
Anal. calcd for C15H30O5: C, 62.04; H, 10.41; found: C, 61.98; H,
10.02%.
4.2. General procedure for the synthesis of alkyl
2-deoxy-˛/ˇ-d-arabino-hexopyranosides
A mixture of ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-
hexopyranoside (Paul and Jayaraman, 2004) (0.3–0.5 g, 1 molar
equiv.), NIS (1.2 molar equiv.), 1-alkanol (1.2 molar equiv.) and 4 Å
MS in CH2Cl2 (10 mL) was stirred at 0 ◦C for 15 min. A solution of
TMSOTf (0.1 molar equiv.) in CH2Cl2 was added and allowed to
stir for 30 min at 0 ◦C, under N2 atmosphere. The reaction mixture
was filtered through a celite pad, the filtrate diluted with CH2Cl2,
washed with aq. NaHCO3 (3 × 50 mL), aq. Na2S2O3 (5%, 3 × 50 mL),
aq. NaCl (3 × 50 mL) and dried (Na2SO4). The solution was con-
centrated and subjected to column chromatography (SiO2). Alkyl
2-deoxy-3,4,6-tri-O-acetyl-d-arabino-hexopyranosides were sepa-
rated (EtOAc/pet. ether). A methanolic solution of NaOMe (0.5 M,
1 mL) was added to a solution of tri-O-acetyl-2-deoxyglucosides
in MeOH and stirred for 8 h at room temperature. The reaction
mixture was neutralized with AcOH/MeOH (1:9, v/v), concen-
trated, and the crude product purified by column chromatography
(SiO2, 5% MeOH/CHCl3), to afford alkyl 2-deoxy-␣-d-arabino-
hexopyranosides and alkyl 2-deoxy-␤-d-arabino-hexopyranosides,
each in ∼30–35% yield, as white solids.
4.2.5. Decyl 2-deoxy-˛-d-arabino-hexopyranoside
(C10-2d-˛-Glc)
[␣]D25 = 86.7 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(d, 1H, J = 5.02 Hz, –OH), 4.75 (d, 1H, J = 5.02, H-1), 4.73 (d, 1H,
J = 4.83 Hz, –OH), 4.41 (t, 1H, J = 5.95 Hz, –OH), 3.62 (m, 1H, H-3), 3.53
(m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24 (m, 1H,
H-5), 3.02 (m, 1H, J = 5.02, H-4), 1.85 (dd, 1H, J = 12.84, 5.02 Hz, H-
2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.84, 3.48 Hz, H-2a), 1.22
(bs, 14H, –CH2), 0.84 (t, 3H, J = 6.97 Hz, –CH3). 13C NMR (75 MHz,
DMSO-d6) ı: 96.5, 73.1, 71.7, 68.1, 66.1, 61.1, 38.1, 32.1, 31.4, 29.1,
28.8, 26.8, 25.9, 22.2, 21.2, 14.1. ESI-MS: m/z calcd for C16 H32O5Na:

M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
95
327.2147; found: 327.2144. Anal. calcd for C16 H32O5: C, 63.13; H,
10.16; found: C, 63.09; H, 10.23%.
and H-6b, overlapped with DMSO residue peak), 2.99 (m, 1H, H-5),
1.93 (ddd, 1H, J = 11.86, 4.90, 1.44 Hz, H-2e), 1.45 (m, 2H, J = 5.85 Hz,
–CH2), 1.22 (m, 19H, H-2a and methylene), 0.83 (t, 3H, J = 6.22 Hz,
–CH3). 13C NMR (75 MHz, DMSO-d6) ı: 100.1, 75.5, 71.7, 71.4, 69.9,
61.8, 38.8, 31.9, 29.7, 29.6, 29.5, 29.4, 26.0, 22.7, 14.1. ESI-MS: m/z
calcd for C18 H36O5Na: 355.2460; found: 355.2460. Anal. calcd for
C18 H36O5: C, 65.03; H, 10.91; found: C, 65.00; H, 10.83%.
4.2.6. Decyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C10-2d-ˇ-Glc)
[␣]D25 = −28.8 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(t, 2H, J = 4.46 Hz, –OH), 4.45 (t, 1H, J = 5.83 Hz, –OH), 4.40 (dd, 1H,
J = 9.58, 1.43 Hz, H-1), 3.72 (m, 2H, –OCH2), 3.67 (ddd, 1H, J = 12.01,
5.83, 1.83 Hz, H-3), 3.45 (m, 1H, J = 5.83 Hz, H-4), 3.33 (m, 2 H, H-6a
and H-6b, overlapped with DMSO residue peak), 3.02 (m, 1H, H-5),
1.92 (ddd, 1H, J = 12.01, 4.98, 1.43 Hz, H-2e), 1.46 (m, 2H, J = 5.84 Hz,
–CH2), 1.22 (m, 15H, H-2a and methylene), 0.84 (t, 3H, J = 6.16 Hz,
–CH3). 13C NMR (75 MHz, CDCl3) ı: 100.1, 75.5, 71.4, 71.3, 69.8, 61.6,
38.8, 31.9, 29.6, 29.5, 29.3, 26.0, 22.7, 14.1. ESI-MS: m/z calcd for
4.2.11. Tridecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C13 -2d-˛-Glc)
[␣]D25 = 81.0 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(d, 1H, J = 5.05 Hz, –OH), 4.75 (d, 1H, J = 5.05 Hz, H-1), 4.73 (d, 1H,
J = 4.88 Hz, –OH), 4.41 (t, 1H, J = 5.92 Hz, –OH), 3.60 (m, 1H, H-3),
3.53 (m, 1H, H-6a), 3.44 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24
(m, 1H, H-5), 3.01 (m, 1H, J = 5.05 Hz, H-4), 1.85 (dd, 1H, J = 12.80,
5.05 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.80, 3.54 Hz,
H-2a), 1.22 (bs, 20H, –CH2), 0.84 (t, 3H, J = 6.98 Hz, –CH3). 13C NMR
(100 MHz, DMSO-d6) ı: 96.4, 73.1, 71.7, 68.1, 66.1, 61.0, 38.0, 29.1,
29.0, 28.9, 28.8, 25.8, 22.1, 14.0. ESI-MS: m/z calcd for C19 H38O5Na:
369.2617; found: 369.2617. Anal. calcd for C19 H38O5: C, 65.86; H,
11.05; found: C, 65.86; H, 11.19%.
C16 H32O5Na: 327.2147; found: 327.2141. Anal. calcd for C16 H32O5:
C, 63.13; H, 10.16; found: C, 63.20; H, 10.53%.
4.2.7. Undecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C11 -2d-˛-Glc)
[␣]D25 = 86.8 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(d, 1H, J = 5.06 Hz, –OH), 4.76 (d, 1H, J = 5.06 Hz, H-1), 4.72 (d, 1H,
J = 4.89 Hz, –OH), 4.42 (t, 1H, J = 5.93 Hz, –OH), 3.60 (m, 1H, H-3),
3.53 (m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.25
(m, 1H, H-5), 3.01 (m, 1H, J = 5.06 Hz, H-4), 1.86 (dd, 1H, J = 12.74,
5.06 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.74, 3.54 Hz,
H-2a), 1.23 (bs, 16H, –CH2), 0.84 (t, 3H, J = 6.47 Hz, –CH3). 13C NMR
(100 MHz, DMSO-d6) ı: 96.4, 73.1, 71.7, 68.1, 66.1, 38.0, 31.3, 29.1,
29.0, 28.9, 28.7, 25.8, 22.1, 14.0. ESI-MS: m/z calcd for C17 H34O5Na:
341.2304; found: 341.2304. Anal. calcd for C17 H34O5: C, 64.12; H,
10.76; found: C, 64.21; H, 10.51%.
4.2.12. Tridecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C13 -2d-ˇ-Glc)
[␣]D25 = −23.5 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(t, 2H, J = 4.54 Hz, –OH), 4.44 (t, 1H, J = 5.92 Hz, –OH), 4.41 (dd, 1H,
J = 9.71, 1.45 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.65 (ddd, 1H, J = 12.20,
5.92, 1.71 Hz, H-3), 3.44 (m, 1H, J = 5.92 Hz, H-4), 3.34 (m, 2H, H-6a
and H-6b, overlapped with DMSO residue peak), 2.99 (m, 1H, H-5),
1.91 (ddd, 1H, J = 12.20, 4.94, 1.45 Hz, H-2e), 1.46 (m, 2H, J = 6.03 Hz,
–CH2), 1.23 (m, 21H, H-2a and methylene), 0.84 (t, 3H, J = 6.52 Hz,
–CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0, 71.6, 70.6, 68.1,
61.2, 38.9, 31.3, 29.2, 29.1, 29.0, 28.9, 28.7, 25.6, 22.1, 14.0. ESI-MS:
m/z calcd for C19 H38O5Na: 369.2617; found: 369.2617. Anal. calcd
for C19 H38O5: C, 65.86; H, 11.05; found: C, 65.58; H, 11.17%.
4.2.8. Undecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C11 -2d-ˇ-Glc)
[␣]D25 = −25.2 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.87
(t, 2H, J = 4.44 Hz, –OH), 4.48 (t, 1H, J = 5.93 Hz, –OH), 4.41 (dd, 1H,
J = 9.58, 1.43 Hz, H-1), 3.71 (m, 2H, –OCH2), 3.66 (ddd, 1H, J = 11.98,
5.93, 1.83 Hz, H-3), 3.44 (m, 1H, J = 5.93 Hz, H-4), 3.46 (m, 2H, H-6a
and H-6b, overlapped with DMSO residue peak), 3.01 (m, 1H, H-5),
1.94 (ddd, 1H, J = 11.98, 4.90, 1.43 Hz, H-2e), 1.45 (m, 2H, J = 5.86 Hz,
–CH2), 1.22 (m, 17H, H-2a and methylene), 0.83 (t, 3H, J = 6.52 Hz,
–CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.3, 77.1, 71.7, 70.7, 68.2,
61.3, 38.9, 31.4, 29.3, 29.1, 29.0, 28.8, 25.7, 22.2, 14.1. ESI-MS: m/z
calcd for C17 H34O5Na: 341.2304; found: 341.2293. Anal. calcd for
C17 H34O5: C, 64.12; H, 10.76; found: C, 63.99; H, 10.47%.
4.2.13. Tetradecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C14 -2d-˛-Glc)
[␣]D25 = 73.8 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.86
(d, 1H, J = 5.09 Hz, –OH), 4.77 (d, 1H, J = 5.09 Hz, H-1), 4.74 (d, 1H,
J = 4.85 Hz, –OH), 4.47 (t, 1H, J = 5.91 Hz, –OH), 3.62 (m, 1H, H-3),
3.54 (m, 1H, H-6a), 3.51 (m, 1H, H-6b), 3.28 (m, 2H, –OCH2), 3.23
(m, 1H, H-5), 3.02 (m, 1H, J = 5.09 Hz, H-4), 1.85 (dd, 1H, J = 12.80,
5.09 Hz, H-2e), 1.46 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.80, 3.51 Hz,
H-2a), 1.21 (bs, 22H, –CH2), 0.83 (t, 3H, J = 6.98 Hz, –CH3). 13C NMR
(100 MHz, DMSO-d6) ı: 96.5, 73.1, 71.8, 68.1, 66.1, 61.1, 38.1, 31.3,
29.1, 28.9, 28.8, 25.9, 22.2, 14.0. ESI-MS: m/z calcd for C20H40O5Na:
383.2773; found: 383.2756. Anal. calcd for C20H40O5: C, 66.63; H,
11.18; found: C, 66.52; H, 11.25%.
4.2.9. Dodecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C12-2d-˛-Glc)
[␣]D25 = 84.8 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(d, 1H, J = 5.10 Hz, –OH), 4.75 (d, 1H, J = 5.10 Hz, H-1), 4.72 (d, 1H,
J = 4.82 Hz, –OH), 4.40 (t, 1H, J = 5.94 Hz, –OH), 3.61 (m, 1H, H-3),
3.53 (m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24
(m, 1H, H-5), 3.02 (m, 1H, J = 5.10 Hz, H-4), 1.85 (dd, 1H, J = 12.84,
5.10 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.84, 3.48 Hz,
H-2a), 1.22 (bs, 18H, –CH2), 0.84 (t, 3H, J = 6.94 Hz, –CH3). 13C NMR
(75 MHz, DMSO-d6) ı: 96.6, 73.2, 71.8, 68.3, 66.3, 61.2, 38.1, 31.5,
29.2, 29.0, 28.9, 26.0, 22.3, 14.2. ESI-MS: m/z calcd for C18 H36O5Na:
355.2460; found: 355.2449. Anal. calcd for C18 H36O5: C, 65.03; H,
10.91; found: C, 64.94; H, 10.86%.
4.2.14. Tetradecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C14 -2d-ˇ-Glc)
[␣]D25 = −23.3 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.83
(m, 2H, –OH), 4.44 (t, 1H, J = 5.87 Hz, –OH), 4.41 (dd, 1H, J = 9.67,
1.47 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.67 (ddd, 1H, J = 11.71, 5.87,
1.87 Hz, H-3), 3.45 (m, 1H, J = 5.87 Hz, H-4), 3.36 (m, 2H, H-6a and
H-6b, overlapped with DMSO residue peak), 3.00 (m, 1H, H-5), 1.92
(ddd, 1H, J = 11.71, 4.97, 1.47 Hz, H-2e), 1.45 (m, 2H, J = 6.32 Hz, –CH2),
1.22 (m, 23H, H-2a and methylene), 0.84 (t, 3H, J = 6.52 Hz, –CH3).
13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0, 71.7, 70.7, 68.1, 61.2,
38.9, 31.3, 29.2, 29.0, 28.9, 28.7, 25.6, 22.1, 13.9. ESI-MS: m/z calcd for
4.2.10. Dodecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C12-2d-ˇ-Glc)
[␣]D25 = −29.8 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(t, 2H, J = 4.48 Hz, –OH), 4.48 (t, 1H, J = 5.91 Hz, –OH), 4.41 (dd, 1H,
J = 9.61, 1.44 Hz, H-1), 3.72 (m, 2H, –OCH2), 3.67 (ddd, 1H, J = 11.86,
5.91, 1.87 Hz, H-3), 3.44 (m, 1H, J = 5.91 Hz, H-4), 3.39 (m, 2H, H-6a
C
20H40O5Na: 383.2773; found: 383.2759. Anal. calcd for C20H40O5:
C, 66.63; H, 11.18; found: C, 67.04; H, 11.16%.

96
M.K. Singh et al. / Chemistry and Physics of Lipids 155 (2008) 90–97
13C NMR (100 MHz, DMSO-d6) ı: 96.4, 72.9, 71.8, 68.0, 66.0, 61.0,
37.9, 31.1, 29.1, 29.0, 28.9, 28.8, 28.7, 28.5, 25.6, 21.9, 13.8. ESI-MS:
m/z calcd for C23H46O5Na: 425.3243; found: 425.3260. Anal. calcd
for C23H46O5: C, 68.61; H, 11.51; found: C, 68.83; H, 11.51%.
4.2.15. Pentadecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C15 -2d-˛-Glc)
[␣]D25 = 76.0 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.85
(d, 1H, J = 5.12 Hz, –OH), 4.75 (d, 1H, J = 5.12 Hz, H-1), 4.72 (d, 1H,
J = 4.82 Hz, –OH), 4.40 (t, 1H, J = 5.94 Hz, –OH), 3.61 (m, 1H, H-3),
3.53 (m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.24
(m, 1H, H-5), 3.02 (m, 1H, J = 5.12 Hz, H-4), 1.85 (dd, 1H, J = 12.84,
5.12 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.84, 3.48 Hz,
H-2a), 1.22 (bs, 24 H, –CH2), 0.84 (t, 3H, J = 6.94 Hz, –CH3). 13C NMR
(100 MHz, DMSO-d6) ı: 96.4, 73.1, 71.7, 68.1, 66.1, 61.0, 38.0, 31.3,
29.1, 28.9, 28.8, 25.8, 22.1, 14.0. ESI-MS: m/z calcd for C21H42O5Na:
397.2930; found: 397.2915. Anal. calcd for C21H42O5: C, 67.34; H,
11.30; found: C, 67.29; H, 11.24%.
4.2.20. Heptadecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C17 -2d-ˇ-Glc)
[␣]D25 = −24.2 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(m, 2H, –OH), 4.44 (t, 1H, J = 5.86 Hz, –OH), 4.41 (dd, 1H, J = 9.67,
1.54 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.67 (ddd, 1H, J = 12.17, 5.86,
1.87 Hz, H-3), 3.45 (m, 1H, J = 5.86 Hz, H-4), 3.36 (m, 2H, H-6a and
H-6b, overlapped with DMSO residue), 3.00 (m, 1H, H-5), 1.92 (ddd,
1H, J = 12.17, 4.97, 1.54 Hz, H-2e), 1.45 (m, 2H, J = 6.32 Hz, –CH2), 1.22
(m, 29H, H-2a and methylene), 0.84 (t, 3H, J = 6.45 Hz, –CH3). 13C
NMR (100 MHz, DMSO-d6) ı: 99.1, 76.9, 71.7, 70.6, 67.9, 61.2, 38.8,
31.1, 29.1, 28.9, 28.8, 28.7, 28.5, 25.4, 21.9, 13.7. ESI-MS: m/z calcd for
4.2.16. Pentadecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C15 -2d-ˇ-Glc)
[␣]D25 = −24.2 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(t, 2H, J = 4.41 Hz, –OH), 4.44 (t, 1H, J = 5.85 Hz, –OH), 4.41 (dd, 1H,
J = 9.68, 1.44 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.66 (ddd, 1H, J = 12.0,
5.85, 1.69 Hz, H-3), 3.45 (m, 1H, J = 5.85 Hz, H-4), 3.36 (m, 2H, H-6a
and H-6b, overlapped with DMSO residue peak), 2.99 (m, 1H, H-
5)1.92 (ddd, 1H, J = 12.0, 5.14, 1.44 Hz, H-2e), 1.45 (m, 2H, J = 6.48 Hz,
–CH2), 1.22 (m, 25H, H-2a and methylene), 0.84 (t, 3H, J = 6.47 Hz,
–CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0, 71.6, 70.7, 68.1,
61.2, 38.9, 31.3, 29.2, 29.1, 29.0, 28.9, 28.7, 25.6, 22.1, 14.0. ESI-MS:
m/z calcd for C21H42O5Na: 397.2930; found: 397.2917. Anal. calcd
for C21H42O5: C, 67.34; H, 11.30; found: C, 67.49; H, 11.25%.
C
23H46O5Na: 425.3243; found: 425.3256. Anal. calcd for C23H46O5:
C, 68.61; H, 11.51; found: C, 68.63; H, 11.40%.
4.2.21. Octadecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C18 -2d-˛-Glc)
[␣]D25 = 61.3 (c 1, MeOH/CHCl3, 1:3, v/v). 1H NMR (400 MHz,
DMSO-d6) ı: 4.86 (d, 1H, J = 5.03 Hz, –OH), 4.77 (d, 1H, J = 5.03 Hz,
H-1), 4.74 (d, 1H, J = 4.85 Hz, –OH), 4.41 (t, 1H, J = 5.93 Hz, –OH),
3.61 (m, 1H, H-3), 3.53 (m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m,
2 H, –OCH2), 3.23 (m, 1H, H-5), 3.01 (m, 1H, J = 5.03 Hz, H-4), 1.85
(dd, 1H, J = 12.83, 5.03 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H,
J = 12.83, 3.52 Hz, H-2a), 1.22 (bs, 30H, –CH2), 0.84 (t, 3H, J = 6.94 Hz,
–CH3). 13C NMR (100 MHz, DMSO-d6) ı: 96.5, 73.1, 71.8, 68.1, 66.1,
61.1, 38.1, 31.3, 29.1, 28.9, 28.8, 25.9, 22.2, 14.0. ESI-MS: m/z calcd for
4.2.17. Hexadecyl 2-deoxy-˛-d-arabino-hexopyranoside
(C16 -2d-˛-Glc)
[␣]D25 = 68.2 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.83
(d, 1H, J = 5.03 Hz, –OH), 4.76 (d, 1H, J = 5.03 Hz, H-1), 4.70 (d, 1H,
J = 4.77 Hz, –OH), 4.39 (t, 1H, J = 5.94 Hz, –OH), 3.61 (m, 1H, H-3),
3.53 (m, 1H, H-6a), 3.46 (m, 1H, H-6b), 3.29 (m, 2H, –OCH2), 3.27
(m, 1H, H-5), 3.01 (m, 1H, J = 5.03 Hz, H-4), 1.85 (dd, 1H, J = 12.77,
5.03 Hz, H-2e), 1.47 (m, 2H, –CH2), 1.41 (dd, 1H, J = 12.77, 3.52 Hz,
H-2a), 1.22 (bs, 26H, –CH2), 0.84 (t, 3H, J = 6.98 Hz, –CH3). 13C
NMR (100 MHz, DMSO-d6) ı: 96.4, 73.1, 71.7, 68.0, 66.0, 61.0, 37.9,
31.3, 29.0, 28.9, 28.8, 28.7, 25.8, 22.1, 13.9. ESI-MS: m/z calcd for
C22H44O5Na: 411.3086; found: 411.3084. Anal. calcd for C22H44O5:
C, 68.00; H, 11.41; found: C, 68.32; H, 11.27%.
C
24H48O5Na: 439.3399; found: 439.3399. Anal. calcd for C24H48O5:
C, 69.19; H, 11.61; found: C, 69.29; H, 11.66%.
4.2.22. Octadecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C18 -2d-ˇ-Glc)
[␣]D25 = −18.0 (c 1, MeOH/CHCl3, 1:3, v/v). 1H NMR (400 MHz,
DMSO-d6) ı: 4.84 (t, 2H, J = 4.66, –OH), 4.43 (t, 1H, J = 5.81 Hz, –OH),
4.40 (dd, 1H, J = 9.41, 1.38 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.67 (ddd,
1H, J = 12.15, 5.81, 1.83 Hz, H-3), 3.44 (m, 1H, J = 5.81 Hz, H-4), 3.35
(m, 2H, H-6a and H-6b, oerlapped with DMSO residue), 2.99 (m,
1H, H-5), 1.92 (ddd, 1H, J = 12.15, 5.11, 1.38 Hz, H-2e), 1.45 (m, 2H,
J = 6.4 Hz, –CH2), 1.22 (m, 31H, H-2a and methylene), 0.84 (t, 3H,
J = 6.31 Hz, –CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0, 71.6,
70.7, 68.1, 61.2, 38.9, 31.3, 29.2, 29.0, 28.9, 28.7, 25.6, 22.1, 14.0. ESI-
MS: m/z calcd for C24H48O5Na: 439.3399; found: 439.3399. Anal.
calcd for C24H48O5: C, 69.19; H, 11.61; found: C, 69.21; H, 11.84%).
4.2.18. Hexadecyl 2-deoxy-ˇ-d-arabino-hexopyranoside
(C16 -2d-ˇ-Glc)
[␣]D25 = −19.0 (c 1, MeOH). 1H NMR (400 MHz, DMSO-d6) ı: 4.84
(t, 2H, J = 4.88 Hz, –OH), 4.43 (t, 1H, J = 5.83 Hz, –OH), 4.41 (dd, 1H,
J = 9.44, 1.37 Hz, H-1), 3.74 (m, 2H, –OCH2), 3.66 (ddd, 1H, J = 12.29,
5.83, 1.82 Hz, H-3), 3.44 (m, 1H, J = 5.83 Hz, H-4), 3.36 (m, 2H, H-6a
and H-6b, overlapped with DMSO residue peak), 2.99 (m, 1H, H-5),
1.92 (ddd, 1H, J = 12.29, 5.00, 1.37 Hz, H-2e), 1.46 (m, 2H, J = 6.43 Hz,
–CH2), 1.22 (m, 27H, H-2a and methylene), 0.84 (t, 3H, J = 6.45 Hz,
–CH3). 13C NMR (100 MHz, DMSO-d6) ı: 99.2, 77.0, 71.6, 70.7, 68.1,
61.2, 38.9, 31.3, 30.7, 29.2, 29.1, 29.0, 28.9, 28.7, 25.6, 22.1, 14.0. ESI-
MS: m/z calcd for C22H44O5Na: 411.3086; found: 411.3087. Anal.
calcd for C22H44O5: C, 68.00; H, 11.41; found: C, 67.86; H, 11.36%.
Acknowledgements
M.K.S. thanks Council of Scientific and Industrial Research, New
Delhi, India, for a research associate fellowship. We thank an anony-
mous referee for suggestions regarding the evolution of the smectic
phase with the binary mixtures.
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