Synthesis, characterization, and antibacterial activity of novel (1H-Benzo[d]imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene, phenoxazine, and oxazine

Article abstract of DOI:10.1002/jhet.1998

A series of novel (1H-benzo[d]imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene, phenoxazine, and oxazine derivatives have been synthesized from 2-(2',4'-dihydroxyphenyl) benzimidazole intermediate. Synthesized compounds 8a-8d are fluorescent in solution,

Full text of DOI:10.1002/jhet.1998

Month 2014
Synthesis, Characterization, and Antibacterial Activity of Novel
(
1H-Benzo[d]imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene,
Phenoxazine, and Oxazine
Vikas S. Patil, Vikas S. Padalkar, Kiran R. Phatangare, Prashant G. Umape, Bhushan N. Borase and N. Sekar*
Tinctorial Chemistry Group, Department of Intermediate and Dyestuff Technology, Institute of Chemical Technology
(
Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019, Maharashtra, India
*
E-mail: n.sekar@ictmumbai.edu.in, nethi.sekar@gmail.com
Received December 11, 2012
DOI 10.1002/jhet.1998
Published online 00 Month 2014 in Wiley Online Library (wileyonlinelibrary.com).
A series of novel (1H-benzo[d]imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene, phenoxazine, and
0
0
oxazine derivatives have been synthesized from 2-(2 ,4 -dihydroxyphenyl) benzimidazole intermediate.
Synthesized compounds 8a–8d are fluorescent in solution, photophysical properties of compounds were
studied and results revealed that compounds absorb and emit in UV–visible region with good fluorescence
ꢀ
quantum yield. Synthesized compounds are thermally stable up to 300 C. The antibacterial activities of
the synthesized compounds were studied by the well-diffusion method. Escherichia coli (ATTC-25922),
Staphylococcus aureus (ATCC-25923), Micrococcus (ATCC-4698), and Bacillus subtilis (ATCC-55422)
were used to investigate the antibacterial activities.
J. Heterocyclic Chem., 00, 00 (2014).
INTRODUCTION
in synthesis and application of these fluorophores [16]
because of their obvious merits. They have been used as
probes in liquid binding to proteins, peptides, DNA [17],
antifungal agents [17], and covalent labeling of model car-
boxylic acids [18] and amino acids [19]. Synthesis of
benzo-phenoxazine dyes such as Meldola’s blue, Nile
Red, Nile blue, and their extensive study in order to in-
crease the quantum yield and solubility in water for efficient
use as labeling for biomolecules [20,21].
Binding proteins offer an alternative approach for
sensing a variety of analytes such as maltose, glucose,
lactate, and other metabolites [15]. In contrast to
enzymatic sensors, fluorophore-labeled binding proteins
require no cofactors and produce no enzymatic
byproducts, a source of potential biosensor degradation
during longer implant times. Binding proteins can be
specific to molecules of biological interest and can
reversibly bind these ligands, properties that are
desirable for constructing continuous biosensors. The
fluorescence properties of such dyes can be correlated to
change in microenvironment associated with the binding
of analyte to protein. These dyes are derivatives of Nile
Red, a phenoxazine that are known to possess a very high
environmental sensitivity [16–28].
Phenoxazine type of organic fluorophores has demon-
strated their potential for displays as recent advances in
organic light-emitting diodes (OLEDs) [1–7]. Emissive
materials capable of accepting both electrons and holes
while exhibiting high luminescence quantum yield are
necessary to improve the performance and durability of
OLEDs [6,7]. This means that the light-emitting molecule
should have very stable radical cations and radical anions,
[
6,7] a requirement that is very similar to that of electro-
generated chemo-luminescence. A molecular design
approach to such multifunctional materials for OLEDs is
to combine distinct electron donor (D) and acceptor (A)
units into a suitable emissive D–A molecule [1–11].
Recent development in the field of electronics mainly in
organic light emitting diodes indicates that there is a desper-
ate need for highly fluorescent compound. Phenoxazine
type of organic fluorophores due to their intrinsic high
fluorescent properties seem to be fulfilling this need [8,9].
Fluorescent properties of phenoxazines are due to donor–
acceptor system existing within the molecules. Charge
transfer of these molecules is controlled by applied poten-
tial difference analogous to transistor and termed as field ef-
fect charge transfer [10,11]. Hence, these kinds of
molecules find application in electronics and are used as
dopant in semiconductor materials. Doping of these mole-
cules produces electron and holes, make them valuable can-
didates and find application in electronics [10–14].
Organic fluorophores are extensively used in labeling of
biomolecules. Phenoxazine nucleic acid from cytosine
analogs have been synthesized recently. A nucleic acid
base cytosine analog has potential to hold structure binding
to a guanine in helical nucleic acids. Along with
primary hydrogen bonding, secondary hydrogen bonding
of the ammonium group shows analogous trend in
phenoxazine nucleic acid-DNA duplexes introduced
Fluorescent dyes belonging to the class of xanthenes,
oxazines, and phenoxazines are highly attractive in biolog-
ical applications. There has been continuous development
©
2014 HeteroCorporation

V. S. Patil, V. S. Padalkar, K. R. Phatangare, P. G. Umape, B. N. Borase, and N. Sekar
Vol 000
secondary hydrogen bonding. All the properties strongly
depend on primary and secondary attach modified
nucleobase of nucleoside [29–31].
at reflux condition in different solvents (Scheme 1). Further
cyclocondensation of DHPBI with 4-(diethylamino)-2-
hydroxy benzaldehyde 5 and 5-(diethylamino)-2-nitrosophenol
6 was carried out at reflux temperature using catalytic
amount of H SO in water for 6 h and in methanol for 16h
Besides the use in electronics and bioconjugation field,
phenoxazines also exhibit antibacterial activity [32]. They
show good antibacterial activity but information available
in these lines is very little. Hence, there is a wide scope for
the synthesis and study the antibacterial activity of novel
phenoxazine. Keeping the above developments in mind,
and as a part of ongoing research on benzimidazole chemis-
try [33,34], we have developed phenoxazine type of long-
wavelength fluorescent dyes suitable for bioconjugation with
significant sensitivity to their microenvironment. Here,
consolidated effort has also been made to synthesis, charac-
terize novel (1H-benzo[d]imidazole-2-yl)-6-(diethylamino)-
2
4
to gave respective compounds 8a and 8b. Nitroso-DHPBI
4 was prepared by dissolving water insoluble DHPBI 3 in
appropriate quantity of 35% alkali solution and controlled
addition of 40% H SO over the period of 0.5–1 h. Nitroso-
2
4
ꢀ
DHPBI 4 was precipitated slowly in 4 h at 0–5 C. Due to
its unstable nature, it was dried under vacuum and used for
further reaction. Nitroso-DHPBI 4 and 2-(morpholin-4-yl)-
1,3-thiazol-4-ol 7 were cyclocondensed with DHPBI 3 in
DMF for 16 h to yield the desired compounds 8c and 8d.
1
All compounds were characterized by FT-IR, H NMR,
3
H-one-xanthene, phenoxazine, and oxazine derivatives
and mass spectral analysis and further described by UV–vis
spectroscopy, molar extinction coefficient, and thermal
stability by Thermo Gravimetric Analysis (TGA). The
details are summarized in Table 1 Figure 3.
from di-hydroxyphenyl benzimidazole.
RESULTS AND DISCUSSIONS
Photophysical properties.
Compound 8a shows dual
Di-hydroxyphenyl benzimidazole (DHPBI) 3 was
prepared by the known method in polyphosphoric acid and
purified by acid-base treatment in water. The xanthene,
phenoxazine, and oxazine compounds 8a–8d were prepared
absorption-emission with absorptions at 316 nm and
550 nm, on excitation at 316 nm two emissions at 370 nm
and 444 nm are observed. Compound 8b shows single
absorption as compared with 8a and absorbs only at
ꢀ
ꢀ
Scheme 1. Reagents and conditions: (a) PPA, 250 C, 4 h; (b) Dil. H
2
SO
4
, reflux, 3 h; (c) Methanol, reflux, 16 h; (d) NaNO
2
, HCl, 0–5 C, 3.5 h; (e)
ꢀ
NaOH, NaNO
2
, H
2
SO
4
, 0–5 C, 3.5 h; (f) DMF, reflux, 16 h.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2014
Synthesis, Characterization, and Antibacterial Activity of Novel (1H-Benzo[d]
imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene, Phenoxazine, and Oxazine
Table 1
Photophysical properties of compounds 8a–8d.
Absorption/excitation l
Emission l max
Molar absorptivity
mol dm cm
Thermal stability
Molecular
formula
Molecular
weight
ꢁ
1
3
ꢁ1
ꢀ
Compounds
max (nm)
(nm)
C (%)
8a
316 (0.869)
370 (0.144)
2462.7
1620.0
—
239
(99.35)
C
24
H
21
N
3
O
2
383
4
44 (0.740)
5
50 (0.058)
—
8
8
8
b
c
316 (0.703)
358 (0.134)
3084.8
334
(96.06)
356
C
C
23
23
H
20
15
N
4
5
O
2
3
384
445
405
4
44 (0.840)
265 (0.248)
—
1517.6
1103.7
1761.8
1445.9
H
N
O
3
28 (0.341)
442 (0.489)
(98.14)
d
280 (0.355)
15 20 5 3
C H N O S
3
31 (0.435)
06 (0.357)
—
3
4
66 (0.030)
50 (0.115)
351
(95.36)
4
1437.8
Figure 2. Absorption of compounds 8a–8d.
Figure 1. UV–vis absorption and fluorescence emission photographs of
dyes 3 and 8a–8d in water.
3
16 nm, and the emission band is split into two at 358 nm
and 444 nm on excitation with 316 nm. Compounds 8a
and 8b give emission on excitation only at 316 nm.
Compound 8c shows absorption at 265 nm and 328 nm
with only single emission at 442 nm on excitation with
3
28 nm. Compound 8d absorbs at three different
wavelengths at 280 nm, 331 nm, and 406 nm. Compound
d on excitation at 331 nm shows emissions at 366 nm
8
and 450 nm. Compounds 8a–8d show good fluorescence
when the solution made in DMF was exposed to UV
3
65 nm (Fig. 1). Graphical representations of absorption
and emission spectra in UV–visible region are shown in
Figures 2 and 3, respectively. A molar extinction
coefficient of all synthesized compounds at each absorption
is found to be less as compared with the commercially
available dyes. (Table 1).
Thermal stability. In order to give more insight into the
dyes 8a–8d, the thermal studies of the compounds have been
carried out using TGA. The thermogravimetric studies have
Figure 3. Emission of compounds 8a–8d.
ꢀ
been carried out in the temperature range 50–600 C under
ꢀ
ꢁ1
nitrogen gas at a heating rate of 10 C min . The TGA
results indicated that the synthesized dyes are stable up to
ꢀ
ꢀ
300 C. Above 280 C, the thermogravimetric curve of the
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

V. S. Patil, V. S. Padalkar, K. R. Phatangare, P. G. Umape, B. N. Borase, and N. Sekar
Vol 000
synthesized compounds show a major loss in weight (Fig. 4).
concentrations test solutions. The plates were incubated for
24 h at 37 C. After 24 h, the zone of inhibitions observed
ꢀ
The comparisons of the T (decomposition temperature)
d
showed that the thermal stability of compound 8d is
found to be more as compared with other compounds
around the holes in each plate was measured. Antibacterial
activity was determined by measuring the diameter zone of
inhibition. Activity of each compound was compared with
ciprofloxacin and sulfametoxazol as standards. These results
are summarized in Table 2 and Figure 5.
(Table 1, Fig. 4).
Biological activity.
The antibacterial activities of the
synthesized compounds were studied by the well-diffusion
method. For this study, Escherichia coli (ATTC-25922),
Staphylococcus aureus (ATCC-25923), Micrococcus
All the synthesized compounds show good activity
against all stains studied. Among four compounds, 8d
shows good activity against all bacterial stains. From
antibacterial activity study, it is observed that concentration
of compound does not affect the activity results in both 0.5
and 1 mg/mL give equivalent results. The results show that
8a–8c contain hydroxy benzimidazole (HBI) are observed
almost similar in activity. 8d contains thiazole moiety
and its antibacterial activity is found to be enhanced. Com-
pounds 8a and 8b contain electron donating diethyl amine,
and inductive as well as mesomeric effects are prevalent;
they show good activity against all strains, but slightly less
against B. subtilis, comparatively same against E. coli,
S. aureus, and Micrococcus. Compound 8c substituted with
electron withdrawing benzimidazole substituent show nil
activity against B. subtilis and comparatively same against
(ATCC-4698), Bacillus subtilis (ATCC-55422) were used
to investigate the antibacterial activities. The synthesized
compounds were tested against the Gram negative bacteria
(E. coli). The bacterial cultures were prepared in infusion
broth for their activity tests. The compounds were
dissolved in DMSO at concentration of 0.5 mg/mL and
1
mg/mL. Antibacterial activity of DMSO against the test
organisms was investigated and found to be nil.
3
Approximately 1 cm of a 24-h broth culture contains
6
ꢁ3
1
0 cfu cm
was placed in sterile Petri dish. Molten
3
ꢀ
nutrient agar (15 cm ), kept at 45 C, was then poured into
the petri dishes and allowed to solidify. The 6 mm diameter
holes were then punched carefully using a sterile cork borer
and completely filled with the test solutions of respective
1
1
20
00
––––––– 3
––––––– 8a
––––––– 8b
––––––– 8c
––––––– 8d
8
6
4
2
0
0
0
0
0
Weight (%)
0
100
200
300
400
500
600
Temperature (°C)
Universal V4.2E TA Instruments
Figure 4. Thermal stability by Thermo Gravimetric Analysis (TGA).
Table 2
Antibacterial activities of compounds 8a–8d.
Escherichia coli
Staphylococcus aureus
Micrococcus
Bacillus subtilis
Compound
0
.5 mg/mL
1 mg/mL
0.5 mg/mL
1 mg/mL
0.5 mg/mL
1 mg/mL
0.5 mg/mL
8
8
8
8
a
b
c
5
6
6
6
9
8
5
6
6
7
—
—
7
5
7
7
16
10
8
7
7
8
—
—
5
6
5
7
18
10
5
6
6
8
—
—
3
4
—
6
20
16
d
Ciplofloxacin
Sulfametoxazol
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2014
Synthesis, Characterization, and Antibacterial Activity of Novel (1H-Benzo[d]
imidazole-2-yl)-6-(diethylamino)-3H-one-xanthene, Phenoxazine, and Oxazine
recorded on a Perkin-Elmer 257 spectrometer using KBr disks.
1
H NMR spectra were recorded on VXR 400-MHz instrument
using TMS as an internal standard. The UV–visible absorption
spectra of the compounds were recorded on a Spectronic
Genesys 2 UV–visible spectrophotometer; UV–visible emission
spectra were recorded on JASCO–FP 1520.
Synthesis
0
0
Synthesis of 2-(2 ,4 -dihydroxyphenyl) benzimidazole 3. 2,4-
Dihydroxy benzoic acid (10 g, 64.9 mmol), and o-
1
phenylenediamine 2 (7.012 g, 64.9 mmol) were mixed in
polyphosphoric acid (121.94 g). The mixture was stirred at
ꢀ
2
50 C for 4 h and then it was allowed to cool at room
temperature, poured over 1200 mL ice-cold water with
constant stirring dark brown precipitate was obtained. It was
filtered, washed with cold water.
Figure 5. Graphical representation of antibacterial activity.
0
0
Purification of 2-(2 ,4 -dihydroxyphenyl) benzimidazole 3.
Dissolved compound 3 in cold solution of 10% Na CO (15.75 g
2
3
E. coli, S. aureus, and Micrococcus. Compound 8d with
five member ring thiazole, electron donating morpholino
substituent is found to have good activity against all stains.
Preferentially, against B. subtilis for which other com-
pounds were found to be nil. Results obtained at both
dissolved in 137 mL of water) acidified with 1:1 HCl (40 mL) at
ꢀ
temperature less than 10 C. This solution was kept overnight in
ꢀ
refrigerator at 0 C solid separated, filtered, and dried. (Scheme 1)
ꢀ
Yield 54%, Melting point = > 300 C.
FT-IR (KBr): 3438 (phenolic O–H), 3322 (N–H), 1651
concentrations against B. Subtilis are same for 8d.
Relative fluorescence quantum yield. Quantum yield of
(imine CN), 1571 (aromatic CC), 1516, 1421, 1389, 1203
(phenol C–O) cm .
ꢁ
1
synthesized compounds was calculated by using Tinopal as
reference standard. Absorption and emission characteristics
of the standard and for compounds in ethanol were
measured at different concentrations at (2, 4, 6, 8, and
1
3 2
H NMR (CD ) SO: d 6.88 (d, 1H, J = 6.4 Hz), 6.88 (d, 1H,
J = 6.4 Hz), 7.05 (s, 1H, J = 1.8 Hz), 7.34 (s, 2H, J = 7.2 Hz ),
7.71 (s, 2H, J = 7.2, 1.8 Hz), 8.07 (s, 1H), 11.2 (s, 1H) ppm.
Mass: m/z 226 (M + 1).
Synthesis of 2-(1H-benzo[d]imidazole-2-yl)-6-(diethylamino)-
H-xanthene-3-one 8a. 4-(Diethylamino)-2-hydroxybenzaldehyde
1.70 g, 8.84 mmol) 5 and 2 (2 ,4 -dihydroxyphenyl) benzimidazole
(2.00 g, 8.84 mmol) mixed together in 30 mL water and H SO
1.73 g, 17.60 mmol) reflux for 6 h gave corresponding xanthene
1
0ppm level). Emission intensity values were plotted
3
(
3
(
against absorbance values and linear plots were obtained.
Gradients were calculated for compounds as well as
standard. All the measurements were carried out by
keeping the parameters constant such as solvent and slit
width. Relative quantum yields of synthesized compounds
in different solvents were calculated by using formula
0
0
2
4
8
a. (Scheme 1)
ꢀ
Yield:63%, Melting point = >300 C.
FT-IR (KBr): 3291, 3072, 2936, 1613, 1516, 1497, 1456,
390, 1316, 1273, 1180, 1093, 1007, 1002, 915, 837, 737 cm .
1
[35]. The quantum efficiency of compound 8a was found
ꢁ
1
1
to be more (0.854) as compared with compounds 8b–8d
1
3 2
H NMR (CD ) SO): d = 1.98 (t, 6H), 3.34 (q, 4H), 6.38
(8b= 0.473, 8c = 0.480, and 8c = 0.612).
(
s, 2H, J = 1.8 Hz), 6.44 (s, 1H), 6.57 (s, 1H), 6.83 (d, 2H,
J = 7.0 Hz), 7.18 (d, 3H, J = 7.8 Hz), 7.38 (d, 2H, J = 7.8 Hz),
.50 (s, 2H) ppm.
Mass: m/z: 384 (M + 1).
Synthesis of 2-(1H-benzo[d]imidazole-2-yl)-6-(diethylamino)-
H-phenoxazin-3-one 8b.
.09 mmol) treated with NaNO
0.995 g 27.2 mmol, 35%) at 0–5 C in 20 mL water for 3.5 h
À
Á
2
2
f ¼ f ðGradX=GradSTÞ ꢀ x=ꢀ ST ;
(1)
X
ST
7
where f is the quantum yield of synthesized compound;
X
fST is the quantum yield of standard used; Grad is the
X
3
9
(
3-(Diethylamino) phenol (1.5 g,
gradient of synthesized compound; Grad is the gradient
X
2
(0.752 g, 10.9 mmol) and HCl
2
ST
of standard used; ꢀ is the refractive index of solvent for
standard sample; and ꢀ is the refractive index of solvent
ꢀ
2
X
give 5-(diethylamino)-2-nitrosophenol 6 (melting point 88–
ꢀ
0
0
for synthesized compound.
90 C). Cyclocondensation of 2-(2 ,4 -dihydroxyphenyl)
benzimidazole 3 (1.164 g, 5.15 mmol) and 5-(diethylamino)-2-
nitrosophenol 4 (1 g 5.15 mmol) reflux in methanol for 16 h
yield 8b. (Scheme 1)
EXPERIMENTAL
Yield: 59%, Melting point = >300 C.
General. All commercial reagents and solvents were procured
from S.D. fine chemicals (India) and were used without
purification. The reaction was monitored by TLC using on
ꢁ
1
FT-IR (KBr, cm ): 3294, 3103, 2978, 2856, 1613, 1493, 1390,
ꢁ1
1
319, 1273, 1173, 1093, 1063, 998, 960, 908, 837, 740 cm .
1
0
.25 mm E-Merck silica gel 60 F254 precoated plates, which
3 2
H NMR (CD ) SO: d = 1.99 (t, 6H), 2.2 (s, 1H), 3.76 (q,
were visualized with UV light. Melting points were measured
on standard melting point apparatus from Sunder industrial
product Mumbai and are uncorrected. The FT-IR spectra were
4H,), 5.98 (s, 1H), 6.38 (d, 2H, J = 6.8 Hz), 6.42 (s, 2H),
6.77 (d, 2H, J = 6.8 Hz ), 7.14 (dd, 3H, J = 7.2, 1.8 Hz), 7.52
(s, 1H), 8.01 (s, 1H) ppm.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

V. S. Patil, V. S. Padalkar, K. R. Phatangare, P. G. Umape, B. N. Borase, and N. Sekar
Vol 000
REFERENCES AND NOTES
Mass: m/z: 385 (M + 1).
0
0
0
Synthesis of 2(2 ,4 -dihydroxy-5 -nitrosophenyl)benzimidazole
0
0
[1] Kraft, A.; Grimsdale, A. C.; Holmes, A. B. Angew Chem Int
4
.
2(2 ,4 -Dihydroxyphenyl) benzimidazole 3 (1g, 4.42mmol)
dissolved in NaOH solution (0.198g, 4.95 mmol 35%) add slowly
NaNO (0.3663g, 5.30mmol 100%) solution and stir it for half
an hour and slowly added H SO (0.5636 g, 5.75 mmol 40%) over
the period of half hour, stir reaction for 3.5 h gave 2(2 ,4 -hydroxy
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4
0
0
0
ꢀ
5
-nitroso phenyl) benzimidazole 4 (melting point 240 C).
(
Scheme 1)
[
Synthesis of 2,8-di(1H-benzo[d]imidazole-2-yl)-7-(diethylamino)-
0 0 0
2(2 ,4 -Dihydroxy-5 -nitrosophenyl)
3
H- phenoxazin-3-one 8c.
benzimidazole 4 (0.5 g, 1.96mmol) and 2(2 ,4 -dihydroxyphenyl)
benzimidazole 3 (0.44 g, 1.96mmol) in DMF reflux for 16h gives
0
0
[
8
c. (Scheme 1)
[
ꢀ
Yield: 68%, Melting point = >300 C.
[
ꢁ
1
FT-IR (KBr): 1570, 1664, 3430–3320 broad cm
.
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1
3 2
H NMR (CD ) SO: d = 3.54 (t, 4H), 3.79 (t, 4H), 5.10 (s, 1H),
[
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5
.37 (s, 1H), 6.4–7.6 (m, 9H), 8.21 (s, 1H) ppm.
[
Mass: m/z: 445 (M + 1).
Synthesis of 7-(1H-benzo[d]imidazol-2-yl)-2-morpholino-6H-
benzo[e]thiazolo[4,5-b][1,4]oxazin-6-one 8d. 2(2 ,4 -Dihydroxy
nitrosophenyl) benzimidazole 4 (0.5 g, 1.96 mmol) refluxed with
-(morpholin-4-yl)-1,3-thiazol-4-ol 7 (0.364 g, 1.96 mmol) in DMF
1
[
0
0
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0
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for 13 h yield 8d. (Scheme 1)
[
ꢀ
Yield: 71%, Melting point = >300 C.
Research Products, 9th edn., Eugene, Oregon: United States, 2002.
ꢁ
1
[
[
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FT-IR (KBr): 1570, 1664, 2856, 2880, 3430–3320 broad cm
.
1
H NMR (CD ) SO): d 3.39 (q, 4H), 3.60 (q, 4H), 6.04–7.90
3
2
(
m, 6H), 6.30 (s, 1H) ppm.
Mass: m/z: 405 (M + 1).
[
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CONCLUSION
In this report, we developed easy and useful method for the
M. S. T. Tetrahedron Lett 2007, 48, 8347.
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[
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azole. Most of these compounds show moderate antibacterial
activity as compared with commercially available standard
compounds. Hence, these may be the lead interest molecules
for the future study in synthetic and biological development.
Conclusion can be made that these classes of compounds
potentially holds great promise towards development of
novel class of antibacterial agents. Further study being
conducted to acquire more information about quantitative
structure–activity relationships.
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[
[
[
[
Acknowledgment. The authors Vikas Patil and Vikas Padalkar
are thankful to Huntsman International LLC for financial support.
[
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet