Studies on a novel class of triaryl pyridine N-glycosylamine amphiphiles as super gelators

Article abstract of DOI:10.1039/c2ob06834f

A novel class of six different triaryl pyridine N-glycosylamine amphiphiles was synthesised and characterized based on different spectral techniques, such as NMR and mass analysis. Gelation properties in different aromatic and aliphatic solvents were studied and gelation was observed predominantly in aliphatic solvents with CGC of 0.5% (w/v) and is attributed to the presence of long alkyl chain. All the gels thus obtained were studied using FE-SEM and powder XRD techniques which reveal fibrous entanglement of the molecules in the gel state with intermolecular spaces of 3.62 nm and 0.43 nm.

Full text of DOI:10.1039/c2ob06834f

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PAPER
Studies on a novel class of triaryl pyridine N-glycosylamine amphiphiles as
super gelators†‡
Manivannan Kalavathi Dhinakaran and Thangamuthu Mohan Das*
Received 1st November 2011, Accepted 21st December 2011
DOI: 10.1039/c2ob06834f
A novel class of six different triaryl pyridine N-glycosylamine amphiphiles was synthesised and
characterized based on different spectral techniques, such as NMR and mass analysis. Gelation properties
in different aromatic and aliphatic solvents were studied and gelation was observed predominantly in
aliphatic solvents with CGC of 0.5% (w/v) and is attributed to the presence of long alkyl chain. All the
gels thus obtained were studied using FE-SEM and powder XRD techniques which reveal fibrous
entanglement of the molecules in the gel state with intermolecular spaces of 3.62 nm and 0.43 nm.
possess antimicrobial activity.22 In addition, this class of deriva-
Introduction
tives is reported to have significance as novel materials in photo-
sensitizers for the conversion of solar energy.23
Gels are viscoelastic materials consisting of low molecular
weight gelator molecules and solvents. Depending upon the
solvent in which the gel is obtained they are classified into
hydrogelator and organogelator.1–4 Multiple interactions, such as
hydrogen bonding, π–π stacking, and hydrophobic interactions,
are mainly responsible for the formation of gels.5 Gelator mol-
ecules and their gels have a wide range of application in tissue
engineering,6 cosmetics,7 as a vehicle for controlled drug deliv-
ery etc.8 In addition, they are used in template syntheses of nano-
particles and inorganic nanostructures,9 sensors,10 and food
processing.11,12 Among the gelators, non-ionic amphiphilic gela-
tors having carbohydrate head groups are reported to have
growing applications in the areas of foods, pharmaceuticals,
detergents13 etc., and this is due to their ready biodegradability,
mildness to skin, non-toxicity and synergistic effects in combi-
nation with anionic amphiphiles.14 Several non-ionic carbo-
hydrate modified products are based on sorbitan,15 glycosides,16
sugar-esters,17 including mannitol monoesters,18 and amides,19
etc.
The structural modification of carbohydrate molecules to
obtain low molecular weight gelators has been an interesting
field of research in recent years.24 Since carbohydrate molecules
are biocompatible, the gels derived from these molecules have
wide application in biology and also as functional materials.25
Moreover, the abundant availability of saccharides enhances
research into the design of novel sugar based gelator molecules.
The self-assembly of sugar based-amphiphilic systems is thus
emerging as a particular powerful strategy to direct the self-
assembly of relatively simple glycosyl amines into sophisticated
materials possessing wide applications. Due to their dual affinity
for polar and non-polar solvents these amphiphiles can self-
assemble to minimize their free energy.26 In addition the gels
can be stabilized by intermolecular hydrogen bonds between
sugar-OH groups as well as van der Waals interactions between
alkyl groups. In the search of new molecular entities with poten-
tial gelation ability, we have recently reported pyridine based N-
glycosylamine and 4,6-O-protected-β-C-glycosides27 as potential
gelators with diverse applications. In the present study we report
a novel class of triaryl pyridine based N-glycosylamine amphi-
philes as super gelators. Thus, the design was such that the
hydrophilic head and hydrophobic tail are connected through a
chromophoric planar base.
In order to prepare gelators and gels with diverse functionality,
we have incorporated the triaryl pyridine nucleus. In general the
3,4,5-triaryl pyridine nucleus is of special interest because of its
close structural resemblance to the recommended photodynamic
cell-specific symmetrical triaryl-telluropyrylium, selenopyrylium
and thiopyrylium cancer therapeutic agents.20 Triaryl pyridine
derivatives also act as G-quadruplex binding ligands21 and
Results and discussion
Triaryl pyridine amine derivatives (5–7) were synthesised from
long alkyl chain substituted benzaldehydes (1–3) and 4-amino-
acetophenone (4) in the presence of NaOH and ammonium
acetate in polyethylene glycol-300 [PEG-300] as reaction
medium (Scheme 1). Three triaryl pyridine amines thus obtained
were glycosylated according to the literature procedure28 leading
Department of Organic Chemistry, University of Madras, Guindy
Campus, Chennai, 600 025, India. E-mail: tmdas_72@yahoo.com;
Fax: +91-44-22352494; Tel: +91-44-22202814
†Dedicated to Professor C. P. Rao.
‡Electronic supplementary information (ESI) available: 1H and 13C
NMR, mass spectra, additional FE-SEM and TEM images. See DOI:
10.1039/c2ob06834f
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Scheme 1 Synthesis of N-glycosylamines 10–15.
products (10–15) were characterized based on NMR (1H and
Table 1 Synthesis of triaryl pyridine N-glycosylamines (10–15)
1
13C) and mass spectral analysis. The H NMR spectra of N-gly-
Compounds
R1
R2
R3
R4
Yield (%)
cosylamines show peaks around 0.8–1.8 ppm, 3.3–4.5 ppm,
5–6 ppm, and 6.6–8.2 ppm corresponding to the alkyl chain, sac-
charide skeleton, glycosyl amine and aromatic groups respect-
ively. Studies further show the existence of the β-anomeric form
with chemical shifts around 4.7 ppm and coupling constants
around 7.8 Hz. However 13C NMR studies show peaks around
18–41 ppm, 72–106 ppm and 110–162 ppm corresponding to
the alkyl chain, saccharide carbon, including acetal and aromatic
carbons respectively (see ESI for details†).
10
11
12
13
14
15
H
H
OC8H17
OC8H17
OC8H17
OC8H17
OC8H17
OC8H17
H
H
H
H
CH3
C3H7
CH3
C3H7
CH3
C3H7
65
72
68
66
80
74
OC8H17
OC8H17
OC8H17
OC8H17
OC8H17
OC8H17
to the formation of glycosyl amines. The identities of all the syn-
thesised N-glycosylamines were confirmed using NMR (1H and
13C), mass spectrometry and elemental analysis. All the syn-
thesised compounds were subjected to gelation studies with a
wide range of solvents and the gels thus obtained were character-
ized using microscopic techniques, viz., FE-SEM, TEM analysis.
Gelation studies
The gelation studies were carried out as per the reported pro-
cedure.33 A known amount of triaryl pyridine amines (5–7)/N-
glycosylamines (10–15) was added to 1 mL of solvent in a glass
vial and heated to dissolve the gelator. After cooling to ambient
temperature, the vial was turned upside down to verify the gel
formation. The reversibility of the gelation was confirmed by
repeated heating, and cooling. The critical gelation concentration
(CGC) of triaryl pyridine amines (5–7) and N-glycosylamines
(10–15) was determined from the minimum amount of gelator
required for the formation of gel at room temperature and the
study was carried out in ten different solvents. Studies further
show that the triaryl pyridine amines do not form gels, whereas
the corresponding N-glycosylated products do form gels, which
is due to the entrapment of solvent molecules between the
Synthesis and characterization
Attempts made to synthesise triaryl pyridine amines by adopting
conventional methods29–31 did not result in the formation of the
expected product. However, by using the one-pot strategy
reported by Smith et al.,32 triaryl pyridine amines (5–7) were
synthesised (Scheme 1) and were characterised based on NMR
and elemental analysis. N-Glycosylation28 of triaryl pyridine
amines (5–7) using 4,6-O-protected-D-glucose derivatives (8, 9)
resulted in the formation of the expected N-glycosylated pro-
ducts (10–15) in 65–80% yield (Table 1). N-Glycosylated
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Fig. 1 Schematic representation of solution to gel transition.
Table 2 Gelation studies of triaryl pyridine N-glycosylamines (10–15)
Status of compound (CGCa %)
Solvent
10
11
12
13
14
15
CHCl3
EtOH
THF
G (1.5) G (1.5) G (1.5) G (1)
G (1.5) G (1.5) G (1.5) G (1)
G (0.5) G (0.5)
G (0.5) G (0.5)
G (0.5) G (0.5)
G (0.5) G (0.5)
PG
G (1.5) PG
G (1)
G (1)
DCM
G (1.5)
S
S
EtOAc
Acetone
IPA
Benzene
Toluene
Hexane
G (2)
S
I
P
P
I
G (1.5) G (1.5) G (1.5) G (0.5) G (0.5)
S
I
S
PG
P
G (1.5) G (0.5) G (0.5)
PG
PG
PG
P
G (1)
G (1)
G (1)
PG
G (1.5)
G (1)
G (1)
PG
Fig. 2 FE-SEM images of gel 13 (1% w/v ethanol): a) solution and b)
gel.
P
P
I
PG
P
a G – gelation, PG – partial gelation, S – soluble, I – insoluble, P –
precipitation. CGC – critical gelation concentration.
fibrous network (Fig. 2b). Thus the FE-SEM analysis reveals the
conversion of spherical particles into fibres upon self-assembly
in the gel state,34 and TEM images of N-glycosylamine 13 also
show nanofibres (see ESI for further details†). Thus FE-SEM
and TEM analysis clearly evidence the formation of gels due to
self-assembly of molecules from the dis-assembled solution state
(Fig. 1).
gelators. The results of gelation are summarised in Table 2. Polar
(ethanol, tetrahydrofuran, ethyl acetate, isopropyl alcohol,
acetone, dichloromethane) and non-polar solvents (hexane,
chloroform, benzene,toluenee) were used for gelation. Among
these, the aliphatic solvents viz., chloroform, dichloromethane,
tetrahydrofuran, ethanol, ethyl acetate, acetone and isopropyl
alcohol were found to be the best for gelation, which is due to
the presence of long alkyl chains. However, among the different
aromatic solvents studied benzene and toluene were found to
form gels. A schematic representation of the sol to gel transition
upon cooling and heating due to self-assembly and dis-assembly
of N-glycosylamines is shown in Fig. 1.
Thermal stability
The main characteristic property of gels obtained from low mol-
ecular weight gelators (LMWG) is the thermo-reversible gel to
solution and vice versa transitions that occur by self-assembly
and dis-assembly of the molecules. The gel to solution transition
temperatures (Tgel) of the gelators have been determined using
the dropping ball method.35 Tgel values for N-glycosylamine 13
in tetrahydrofuran, ethanol and chloroform as a function of con-
centration are shown in Fig. 3. As the concentration increases the
Tgel increases and attains stability near the boiling point. Tetra-
hydrofuran and ethanol also show similar trends in gel melting
temperature, while chloroform has same Tgel of 58 °C from a
concentration of 35 mg mL−1 to 50 mg mL−1. The studies
further reveal that the gels of compound 13 are thermally more
stable even at temperatures nearer to the boiling point of the
solvent, which is due to the self-assembly of the molecules and
is further evidenced from the morphological studies.
Morphological studies
The morphology of N-glycosylamines in solution and gel state
were studied with FE-SEM and TEM analysis using 1% w/v of
N-glycosylamine 13 in ethanol. FE-SEM images (Fig. 2a) of N-
glycosylamine 13, recorded immediately after heating the com-
pound 13 (1% w/v) in ethanol, show a spherical structure which
is due to the identical state of the N-glycosylamine molecules in
solution. However cooling the solution to room temperature for a
period of 1 h leads to the formation of a gel, which shows a
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Fig. 3 Concentration dependent melting temperature of gels of com-
pound 13 in THF, EtOH and CHCl3.
Fig. 5 Absorption spectra of a) 10, b) 11, c) 12, d) 13, e) 14 and f) 15
in ethanol at 1 × 10−5 M concentration.
Fig. 4 Powder XRD pattern of xerogel 13.
Fig. 6 Emission spectra of a) 10, b) 11, c) 12, d) 13, e) 14 and f) 15 in
XRD analysis of the gels
ethanol at 1 × 10−5 M concentration.
In order to study the molecular packing in the gel, WAXD (wide
angle X-ray diffraction) studies was carried out on the xerogel of
N-glycosylamine 13. The XRD pattern of xerogel 13 is shown in
Fig. 4. The X-ray diffractogram reveals a lamellar structure,36
which is due to the ordered packing of molecules in the gel state.
A sharp peak at low angle 2.48° (2θ) with an interlayer distance
of 3.62 nm arises from the packing of the long alkyl chain due
to van der Waals interactions. The diffraction in the wide-angle
region around 20.55° (2θ) gives a very broad peak with an inter-
layer distance of 0.43 nm attributable to the π–π stacking37 of
the triaryl pyridine unit in the self-assembled state. Thus the
XRD analysis confirms the self-assembly of the molecules in the
gel state.
Conclusion
A one-pot facile modified literature procedure has been adopted
to synthesise triaryl pyridine amines and their corresponding gly-
cosylated products in good yield. Identities of all the synthesised
compounds were confirmed using NMR and mass spectral tech-
niques. Gelation studies reveal that the N-glycosylamines are
super gelators. Morphological studies using FE-SEM and TEM
show fibrous networks of the N-glycosylamines in the gel state.
Thus triaryl pyridine N-glycosylamines act as amphiphilic gela-
tors due to the hydrophobic tail and hydrophilic head that are
linked through a chromophoric triaryl pyridine moiety.
Experimental section
Photophysical studies
Materials
The chromophoric nature of the N-glycosylamines 10–15 was
investigated using absorption and emission spectroscopy. The
absorption spectra of the N- glycosylamines have been recorded
at a concentration of 1 × 10−5 M in ethanol. N-Glycosylamines
10–15 show characteristic absorption bands in the range of
300–320 nm and 340–360 nm (Fig. 5). On excitation of the N-
glycosylamines at their absorption maxima of 300–320 nm they
show corresponding emission in the range of 450–500 nm
(Fig. 6).
Polyethylene glycol-300 (PEG-300), 4-aminoacetophenone, and
butyraldehyde were purchased from Sigma Aldrich chemicals
Pvt. Ltd. USA. Hydrochloric acid, NaOH, D-glucose, ethanol
were purchased from SRL India Ltd., were of high purity and
were used without further purification. Column chromatography
was performed on silica gel (100–200 mesh). NMR spectra were
recorded on a Bruker DRX 300 MHz instrument in CDCl3 (with
a few drops of DMSO-d6). Chemical shifts are referenced to
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2,6-Bis-(4(4,6-O-butylidene-β-D-glucopyranosyl-amino)phenyl)-
4-(4-O-octyl-phenyl)pyridine (11). Compound, 11 was obtained
by the reaction of the mono-octyl derivative of triaryl pyridine
amine, 5, with 4,6-O-butylidene-D-glucopyranose, 9 as an
orange yellow solid; 0.65 g (yield, 72%); mp: 170–172 °C; [α]D
−30 (c 0.1% in ethanol); 1H NMR (300 MHz, CDCl3 + DMSO-
d6, ppm): δH 7.98 (d, J = 8.4 Hz, 4H, Ar-H); 7.70–7.59 (m, 4H,
Ar-H); 6.96 (d, J = 8.7 Hz, 2H, Ar-H); 6.79 (d, J = 8.4 Hz, 4H,
Ar-H); 6.04 (d, J = 6.6 Hz, 2H, Gly-NH); 5.21 (s, 2H, Sacc-
OH); 5.01 (s, 2H, Sacc-OH); 4.58 (t, J = 7.5 Hz,2H, Ano-H);
4.51 (t, J = 4.8 Hz, 2H, Ace-H); 4.10 (d, J = 6 Hz, 2H, Sacc-H);
3.97 (t, J = 6.6 Hz, 2H, OCH2); 3.60 (t, J = 4.5 Hz, 2H, Sacc-
H); 3.42–3.32 (m, 8H, Sacc-H); 1.77–1.72 (m, 4H, CH2);
1.58–1.53 (m, 4H, CH2); 1.41–1.23 (m, 12H, CH2); 0.78–0.88
(m, 9H, CH3). 13C NMR (75 MHz, CDCl3 + DMSO-d6, ppm):
δC 164.6 (2C, Ar-C); 161.5 (1C, Ar-C); 153.8 (2C, Ar-C); 152.3
(1C, Ar-C); 135.8 (2C, Ar-C); 134.3 (2C, Ar-C); 132.9 (4C, Ar-
C); 132.6 (4C, Ar-C); 119.8 (2C, Ar-C); 119.3 (1C, Ar-C);
118.5 (2C, Ar-C); 106.9 (2C, Ace-C); 91.1 (2C, Ano-C); 85.5
(2C, Sacc-C); 78.9 (2C, Sacc-C); 78.7 (2C, Sacc-C); 78.1 (1C,
OCH2); 72.8 (2C, Sacc-C); 72.1 (2C, Sacc-C); 41.1 (2C, CH2);
36.5 (1C, CH2); 34.0 (1C, CH2); 33.9(2C, CH2); 30.7 (2C,
CH2); 27.3 (1C, CH2); 22.2 (2C, CH2); 18.9 (2C, CH3); 18.8
(1C, CH3). Anal. Calcd for C51H67N3O11: C,68.21; H, 7.52; N,
4.68. Found: C, 68.11; H,7.46; N, 4.71%. EI-MS: m/z calcd for
C51H67N3O11. 897.47, found 898.67.
internal TMS. FE-SEM images were recorded on a Hitachi
SU-6600 instrument. Mass spectra were recorded using a
Thermo Finnigan-ESI mass spectrometer, and optical rotation
was performed using a Rudolph-Autopol II digital polarimeter.
Elemental analyses were carried out on
microanalyser.
a Thermoquest
Synthesis of 2,6-bis(4-aminophenyl)-4-(alkyloxyphenyl) pyridine
(5–7)31
To a stirred solution of 4-aminoacetophenone, 4 (4 mmol), and
NaOH (4 mmol) in PEG-300, 2 mmol of benzaldehyde deriva-
tive (1–3) was added and heated to 100 °C. After stirring for 3 h
the temperature was reduced to 70 °C and ammonium acetate
(2 g) was added, then the temperature was increased to 100 °C
and stirring continued for a further 3 h. After completion of the
reaction, the reaction mixture was poured on to crushed ice, and
the precipitate thus obtained was filtered and further purified by
crystallization to obtain 2,6-bis(4-aminophenyl)-4-(alkyloxyphe-
nyl)pyridines, 5–7, in 73–85% yield.
General procedure for the synthesis of 2,6-bis-(4(4,6-Ο-protected-
β-D-glycopyranosy-amino)-phenyl)-4-(alkoxy-phenyl) pyridines
(10–15)
To a stirred solution of 2 mmol of 4,6-O-protected-D-glucose
derivatives (8) in 5 ml of ethanol, 1 mmol of alkyl substituted
triaryl pyridine amine (5) was added. The reaction mixture was
stirred at 50 °C for 10 min and at room temperature for 24 h.
The reaction was monitored through TLC. The solid N-glycosy-
lamine (10) which separated was filtered off, washed with
ethanol and dried with ether. These N-glycosyl amines are of sat-
2,6-Bis-(4(4,6-O-ethylidene-β-D-glucopyranosyl-amino)phenyl)-
4-(3,4 di-O-octyl-phenyl)pyridine (12). Compound 12 was
obtained by the reaction of the di-O-octyl derivative of triaryl
pyridine amine 6 with 4,6-O-ethylidene-D-glucopyranose 8 as an
orange yellow solid; 0.66 g (yield, 68%); mp: 165–168 °C; [α]D
−32 (c 0.1% in ethanol); 1H NMR (300 MHz, CDCl3 + DMSO-
d6, ppm): δH 7.98 (d, J = 7.8 Hz, 2H, Ar-H); 7.91 (d, J = 7.5 Hz,
2H, Ar-H); 7.64 (s, 2H, Ar-H); 7.25–7.20 (m, 2H, Ar-H); 6.95
(d, J = 8.4 Hz, 1H, Ar-H); 6.80 (d, J = 8.4 Hz, 2H, Ar-H); 6.71
(d, J = 8.1 Hz, 2H, Ar-H); 6.00 (s, 1H, Gly-NH); 4.69 (d, 2H, J
= 4.8 Hz, Ace-H); 4.59 (d, 2H, J = 6 Hz, Ano-H); 4.09-3.97 (m,
8H, OCH2, Sacc-OH, H); 3.73–3.61 (m, 13H, OCH2, Sacc-H);
1.78 (s, 6H, CH2); 1.45 (d, J = 3.6 Hz, 6H, CH2); 1.31–1.23 (m,
18H, CH2, CH3); 0.82 (s, 6H, CH3). 13C NMR (75 MHz,
CDCl3 + DMSO-d6, ppm): δC 161.6 (1C, Ar-C); 154.8(1C, Ar-
C); 154.2 (1C, Ar-C); 153.5 (2C, Ar-C); 152.2 (1C, Ar-C);
136.8 (1C, Ar-C); 134.5 (1C, Ar-C); 133.3 (1C, Ar-C); 132.8
(2C, Ar-C); 132.6 (2C, Ar-C); 124.8 (1C, Ar-C); 119.4 (2C, Ar-
C); 118.9 (2C, Ar-C), 118.5 (2C, Ar-C); 117.8 (1C, Ar-C); 104.1
(2C, Ace-C); 91.2 (2C, Ano-C); 85.4 (2C, Sacc-C); 78.9 (2C,
Sacc-C); 78.7 (2C, Sacc-C); 74.4 (1C, OCH2); 74.0 (1C, OCH2);
73.3 (2C, Sacc-C); 71.9 (2C, Sacc-C); 36.5 (2C, CH2); 34.1 (2C,
CH2); 34.0 (2C, CH2); 33.9 (2C, CH2); 30.8 (2C, CH2); 30.8
(2C, CH2); 27.3 (2C, CH2); 25.3 (2C, CH3); 18.9 (2C, CH3).
Anal. Calcd for C55H75N3O12: C, 68.09; H, 7.79; N, 4.33.
found: C, 68.15; H, 7.75; N, 4.29%.
1
isfactory purity and have been characterized using H and 13C
NMR and mass analysis. A similar procedure was adopted for
the synthesis of compounds 11–15.
2,6-Bis-(4(4,6-O-ethylidene-β-D-glucopyranosyl-amino) phenyl)-
4-(4-O-octyl-phenyl)pyridine (10). Orange yellow solid; 0.55 g
(yield, 65%); mp: 160–163 °C; [α]D −22 (c 0.1% in ethanol);
1H NMR (300 MHz, CDCl3 + DMSO-d6, ppm): δH 7.98 (d, J =
8.1 Hz, 4H, Ar-H); 7.64–7.59 (m, 4H, Ar-H); 6.96 (d, J = 8.4
Hz, 2H, Ar-H); 6.79 (d, J = 8.4 Hz, 4H, Ar-H); 5.97 (d, 2H, J =
6.6 Hz, Gly-NH); 5.11 (s, 2H, Sacc-OH), 5.06 (s, 2H, Sacc-OH);
4.69 (d, J = 4.8 Hz, 2H, Ace-H); 4.59 (t, J = 7.8 Hz, 2H, Ano-
H); 4.08 (d, J = 6 Hz, 2H, Sacc-H); 3.96 (t, J = 6.6 Hz, 4H,
OCH2, Sacc-H); 3.76–3.61 (m, 2H, Sacc-H); 3.44–3.20 (m, 6H,
Sacc-H); 1.77–1.70 (m, 2H, CH2); 1.31–1.23 (m, 16H, CH2 &
CH3); 0.82–0.80 (m, 6H, CH3). 13C NMR (75 MHz, CDCl3 +
DMSO-d6, ppm): δC 164.1 (2C, Ar-C); 161.1 (1C, Ar-C); 153.8
(2C, Ar-C); 151.7 (1C, Ar-C); 135.7 (2C, Ar-C); 134.6 (2C, Ar-
C); 132.4 (4C, Ar-C); 132.2 (4C, Ar-C); 119.3 (2C, Ar-C);
118.1 (3C, Ar-C); 103.7 (2C, Ace-C); 90.7 (2C, Ano-C); 84.9
(2C, Sacc-C); 78.5 (2C, Sacc-C); 78.2 (2C, Sacc-C); 72.6 (1C,
OCH2); 72.4 (2C, Sacc-C); 71.4 (2C, Sacc-C); 36.0 (1C, CH2);
33.6 (1C, CH2); 33.4 (1C, CH2) 30.3 (2C, CH2); 26.9 (1C,
CH2); 25.8 (2C, CH3); 18.5 (1C, CH3). Anal. Calcd for
C47H59N3O11: C, 67.04; H, 7.06; N, 4.99. Found: C, 67.20;
H,7.16, N, 4.94%. EI-MS: m/z calcd for C47H59N3O11. 841.41,
found 842.47.
2,6-Bis-(4(4,6-O-butylidene-β-D-glucopyranosyl-amino)phenyl)-
4-(3,4 di-O-octyl-phenyl)pyridine (13). Compound 13 was
obtained by the reaction of the di-O-octyl derivative of triaryl
pyridine amine 6 with 4,6-O-butylidene-D-glucopyranose, 8 as
an orange yellow solid; 0.68 g (yield, 66%); mp: 175–178 °C;
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1
[α]D −13 (c 0.1% in ethanol); H NMR (300 MHz, CDCl3 +
OH); 4.58 (t, J = 7.2 Hz, 2H, Ano-H); 4.50 (d, J = 4.8 Hz, 2H,
Ace-H); 4.12-4.08 (m, 6H, OCH2); 3.93 (t, J = 6.3 Hz, 4H,
Sacc-H); 3.72 (d, J = 6.6 Hz, 2H, Sacc-H); 3.63–3.43 (m, 6H,
Sacc-H); 1.78–1.68 (m, 8H, CH2); 1.56–1.54 (m, 8H, CH2);
1.40(s, 30H, CH2); 0.88 (s, 15H, CH3). 13C NMR (75 MHz,
CDCl3 + DMSO-d6, ppm): δC 161.4 (1C, Ar-C); 158.2 (4C, Ar-
C); 154.7 (2C, Ar-C); 152.3 (2C, Ar-C); 143.4 (2C, Ar-C);
139.5 (2C, Ar-C); 134.3 (2C, Ar-C), 132.7 (4C, Ar-C); 118.8
(1C, Ar-C); 118.5 (2C, Ar-C); 110.4 (1C, Ar-C); 106.9 (2C,
Ace-C); 91.1 (2C, Ano -C); 85.5 (2C, Sacc-C); 78.9 (1C,
OCH2); 78.7 (2C, Sacc-C); 78.1 (2C, OCH2); 73.9 (2C, Sacc-
C); 73.1 (2C, Sacc-C); 72.1 (2C, Sacc-C); 41.1 (2C, CH2); 36.6
(2C, CH2); 36.5 (2C, CH2); 35.1 (2C, CH2); 34.2 (2C, CH2);
34.1 (2C, CH2); 34.0 (2C, CH2); 30.9 (2C, CH2); 27.4 (2C,
CH2); 27 (2C, CH2); 22.2 (2C, CH2); 18.9 (2C, CH3); 18.8 (3C,
CH3). Anal. Calcd for C67H99N3O13: C, 69.70; H, 8.64; N, 3.64.
Found: C, 69.82; H, 8.81; N, 3.68%. EI-MS: m/z calcd for
C67H99N3O13 1153.71, found 1154.80
DMSO-d6, ppm): δH 7.97 (d, J = 8.4 Hz, 2H, Ar-H); 7.91 (d, J =
8.4 Hz, 2H, Ar-H); 7.55 (s, 2H, Ar-H); 7.22-7.17 (m, 2H, Ar-H);
6.92 (d, J = 8.1 Hz, 1H, Ar-H); 6.78 (d, J = 8.4 Hz, 2H, Ar-H);
6.70 (d, J = 8.4 Hz, 2H, Ar-H); 5.80 (s, 1H, GlyNH); 4.60 (t, J
= 7.8 Hz, 2H, Ano-H); 4.51 (d, J = 4.8 Hz, 2H, Ace-H);
4.12–4.10 (s, 2H, Sacc-OH); 4.03–3.91 (m, 7H, OCH2, Sacc-H,
Gly-NH); 3.67 (t, J = 9 Hz, 2H, OCH2); 3.44–3.37 (m, 9H,
Sacc-H); 1.77 (s, 6H, CH2); 1.59–1.56 (m, 4H, CH2); 1.43–1.22
(m, 22H, CH2); 0.87–0.83 (m, 12H, CH3). 13C NMR (75 MHz,
CDCl3 + DMSO-d6, ppm): δC 161.6 (1C, Ar-C); 154.8 (2C, Ar-
C); 154.2 (2C, Ar-C); 153.1 (2C, Ar-C); 151.0 (1C, Ar-C);
136.8 (1C, Ar-C); 133.7 (1C, Ar-C); 132.8 (2C, Ar-C); 132.7
(2C, Ar-C); 124.7 (2C, Ar-C); 119.5 (2C, Ar-C); 118.8 (2C, Ar-
C); 118.6 (2C, Ar-C); 117.8 (1C, Ar-C); 107.0 (2C, Ace-C);
91.1 (2C, Ano-C); 85.3 (2C, Sacc-C); 78.9 (2C, Sacc-C); 78.7
(2C, Sacc-C); 74.4 (1C, OCH2); 73.9 (1C, OCH2); 73.2 (2C,
Sacc-C); 72.0 (2C, Sacc-C); 41.0 (2C, CH2); 36.5 (2C, CH2);
34.1 (2C, CH2); 34.1 (2C,CH2); 33.9 (2C, CH2); 30.8 (2C,
CH2); 27.3 (2C, CH2); 22.1 (2C, CH2); 18.8 (2C, CH3); 18.7
(2C, CH3). Anal. Calcd for C59H83N3O12: C,69.05; H, 8.15; N,
4.09. found: C, 69.20; H, 8.05; N, 4.06%.
Acknowledgements
The authors acknowledge SERC-DST, New Delhi, India for
financial support. We thank SERC-DST, New Delhi, India for
NMR facilities under the DST-FIST scheme to the Department
of Organic Chemistry, University of Madras, Chennai, India, and
we acknowledge the National Centre for Nanoscience and Nano-
technology, University of Madras, Chennai, India for FE-SEM
analysis and financial support. M. K. D thanks UGC, New
Delhi, India for a Junior Research Fellowship.
2,6-Bis-(4(4,6-O-ethylidene-β-D-glucopyranosyl-amino)phenyl)-
4-(3,4,5 tri-O-octyl-phenyl)pyridine (14). Compound, 14 was
obtained by the reaction of the tri-O-octyl derivative of triaryl
pyridine amine 7 with 4,6-O-ethylidene-D-glucopyranose, 8 as a
yellow orange solid; 0.88 g (yield, 80%); mp: 178–182 °C; [α]D
−48 (c 0.1% in ethanol); 1H NMR (300 MHz. CDCl3 + DMSO-
d6, ppm): δH 7.99 (d, J = 8.4 Hz, 4H, Ar-H); 7.58 (s, 2H, Ar-H);
6.84 (s, 2H, Ar-H); 6.79 (d, J = 8.7 Hz, 4H, Ar-H); 6.05 (s, 2H,
Gly-NH); 5.09 (s, 4H, Sacc-OH); 4.68 (d, J = 4.8 Hz, 2H, Ace-
H); 4.56 (t, J = 7.8 Hz, 2H, Ano-H); 4.03 (t, J = 6 Hz, 6H,
-OCH2); 3.92 (t, J = 6.3 Hz, 4H, Sacc-H); 3.61–3.54 (m, 2H,
Sacc-H); 3.47–3.33 (m, 6H, Sacc-H); 1.80–1.66 (m, 8H, CH2);
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2082 | Org. Biomol. Chem., 2012, 10, 2077–2083
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