Microwave Assisted Synthesis of 5-[4-(3-Phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole Derivatives and Their Antimicrobial Activity

Article abstract of DOI:10.1134/S1070363219090275

In the present study, we report the synthesis of 5-[4-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole derivatives by the Michael addition of chalcones to hydrazine hydrate in presence of acetic acid under conventional heating and microwave irradiation. All the synthesized compounds are characterized by IR, NMR, and mass spectra. The products are screened for their in vitro antimicrobial activity against strains such as Staphylococcus aurous, Bacillus subtilis, Klebsiella pneumonia, Escherichia coli, Aspergillus Niger, Aspergillus flavus, and Fusarium oxysporum. Most of the compounds exhibit high activity.

Full text of DOI:10.1134/S1070363219090275

ISSN 1070-3632, Russian Journal of General Chemistry, 2019, Vol. 89, No. 9, pp. 1905–1910. © Pleiades Publishing, Ltd., 2019.
Microwave Assisted Synthesis
of 5-[4-(3-Phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole
Derivatives and Their Antimicrobial Activity
a
a
a
b
D. Ashok *, N. Nagaraju , B. Vijaya Lakshmi , and M. Sarasija
a
Green and Medicinal Chemistry Laboratory, Department of Chemistry, Osmania University,
Hyderabad, Telangana, 500007 India
*
e-mail: ashokdou@gmail.com
b
Department of Chemistry, Satavahana University, Karimnagar, Telangana, 505001 India
Received June 22, 2019; revised September 10, 2019; accepted September 13, 2019
Abstract—In the present study, we report the synthesis of 5-[4-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-
tetrazole derivatives by the Michael addition of chalcones to hydrazine hydrate in presence of acetic acid under
conventional heating and microwave irradiation. All the synthesized compounds are characterized by IR, NMR,
and mass spectra. The products are screened for their in vitro antimicrobial activity against strains such as
Staphylococcus aurous, Bacillus subtilis, Klebsiella pneumonia, Escherichia coli, Aspergillus Niger, Aspergillus
flavus, and Fusarium oxysporum. Most of the compounds exhibit high activity.
Keywords: acetophenone, 4-(1H-tetrazol-5-yl)benzaldehyde, microwave irradiation, antimicrobial activity
DOI: 10.1134/S1070363219090275
INTRODUCTION
RESULTS AND DISCUSSION
Tetrazole derivatives are broadly screened and well
documented as biologically active compounds. Fairly
recently the drugs Pemirolast [1] and Pranlukast [1]
containing the NH unsubstituted tetrazole ring were in-
troduced as a new generation of antihistaminic drugs, that
effectively acted on both H1 and H2 receptors of mast
cells. Pyrazoles are present as a core structural block in
a wide variety of compounds that demonstrate important
4-(1H-Tetrazol-5-yl)benzaldehyde (2) was derived
from 4-formylbenzonitrile (1) and sodium azide in the
presence of CuSO ·5H O. Its following reaction with
4
2
acetophenones 3a–3i under basic conditions gave the
corresponding chalcones 4a–4i (Scheme 1). The latter
semiproducts were cyclised with hydrazine hydrate in
acidic media under conventional heating and microwave
irradiation to furnish the title compounds 5a–5i in high
yields. Microwave irradiation led to higher yield of the
products within shorter reaction time than conventional
heating (Table 1).
pharmaceutical activities including antimicrobial [2],
antiviral [3], anti-inflammatory [4, 5], cytotoxic [6], and
many more.
Synthesis of heterocyclic compounds under micro-
wave irradiation is usually characterized by enhanced
reaction rate, higher yield and purity of products making
this approach to be a powerful tool for rapid and efficient
synthesis [7–9].
Antibacterial activity. The synthesized compounds
5a–5i were tested in vitro for their antibacterial activity
against gram-positive strains [Staphylococcus aureus
(ATCC 6538), Bacillus subtilis (ATCC 6633)] and gram-
negative strains [Escherichia coli (ATCC 25922), Klebsi-
ella pneumonia (ATCC 13883)] using gatifloxacin as the
standard drug. The activity was determined using filter
paper disc method by measuring the zone of inhibition in
mm. The compounds were tested at the concentrations of
20 and 40 μg/mL in DMSO (Table 2). The compound 5f
exhibited good activity against all bacterial strains. The
compounds 5b, 5c, 5d, and 5g demonstrated promising
Inspired by the above and in continuation to our earlier
studies of synthesis of tetrazoles derivatives, we have de-
veloped the synthetic approach to novel hybrid molecules
containing tetrazole and pyrazole active pharmacophores
under conventional and microwave irradiation methods.
All the synthesized compounds were screened for their
in vitro antimicrobial activity.
1
905

1906
ASHOK et al.
Scheme 1. Synthesis of 5-[4-(3-phenyl-4, 5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole derivatives (5a–5i) under conven-
tional (method a) and microwave irradiation (method b) conditions.
NaN3,
CHO
CHO
CuSO ·5H O (2 mol %)
4
2
DMSO, 140qC
N
N
N
NH
N
1
2
O
H C
3
R
O
3
aꢀ3i
R
KOHꢀEtOH,
room temperature
N
N
NH
N
4
aꢀ4i
NH NH ·H O
2
2
2
AcOH, NaOAc, Method aꢁ
DMF, 80ꢀ90qC
Method b
N
HN
R
N
N
NH
N
5
aꢀ5i
R = 4-H (3a–5a), 4-F (3b–5b), 4-Cl (3c–5c), 4-Br (3d–5d), 4-CH (3e–5e), 4-OCH (3f–5f), 3-OH (3g–5g), 3-Cl (3h–5h), 3-Br
3
3
(3i–5i). Method a: conventional heating; method b: microwave irradiation.
activity, whereas compounds 5a, 5e, 5h, and 5i were of
moderate activity.
Microwave initiated reactions were carried out in a
Milestone multi SYNTH microwave system. All reac-
tions were monitored by TLC on Merck Kieselgel 60
F524, and visualized under UV light and/or by spraying
Antifungal activity. Antifungal activity of the synthe-
sized compounds 5a–5i was tested against three patho-
genic fungi, Aspergillus niger, Aspergillus flavus, and
Fusarium oxysporum using amphotericin B as the stan-
dard drug. Activity was determined using the cup plate
agar diffusion method by measuring the zone of inhibition
in mm. The compounds were screened at concentration
of 50 μg/mLin DMSO (Table 2). The fluorine substituted
compound 5b and methoxy derivative 5f demonstrated
the highest activity against the other compounds charac-
terized as moderately activite.
5
% solution of H SO in ethanol followed by heating.
2 4
Column chromatography was carried out on Silica Gel 60
60–120 mesh). Melting points were determined in open
(
glass capillaries on a Stuart SMP30 apparatus and are
uncorrected. Element analysis was carried out on a Ther-
mofinnigan CHNS analyzer. IR spectra were recorded
in KBr on a Shimadzu FTIR 8400S spectrophotometer.
NMR spectra were measured on a Bruker 400 NMR
spectrometer using DMSO-d as a solvent and TMS as
6
an internal standard. Mass spectra were measured on a
Shimadzu mass spectrometer.
EXPERIMENTAL
All reagent grade chemicals were purchased from
Synthesis of substituted 5-[4-(3-phenyl-4,5-
Sigma Aldrich and used without further purification.
dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole de-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 9 2019

MICROWAVE ASSISTED SYNTHESIS
1907
Table 1. Reaction time and yield of compounds 5a–5i synthesized under different conditions
Time
Yield, %
conventional heating microwave irradiation
Product
mp, °C
conventional
heating, h
microwave irradiation,
min
5
a
172–174
161–163
155–157
172–174
192–194
186–188
171–173
184–186
178–180
8
7
8
7
7
7
8
7
8
8
9
60
65
62
63
50
61
62
65
69
75
77
80
79
76
72
80
72
75
5
b
5
c
8
5
d
10
9
5
e
5
f
10
10
9
5
g
5
h
5
i
8
Table 2. In vitro antibacterial and antifungal activity data for compounds 5a–5i
Inhibition zone, mm
gram-positive bacteria
S. aureus B. subtilis
gram-negative bacteria
E. coli K. pneumoniae A. niger A. flavus F.oxysporum
concentration, μg/mL
fungi
Compound
2
0
14
18
17
15
13
22
17
13
13
20
–
40
20
16
18
17
16
14
23
17
14
14
20
–
40
25
38
28
24
22
40
23
22
20
40
–
20
13
16
15
13
11
16
11
11
15
15
–
40
12
23
16
18
15
21
24
15
12
20
–
20
5
40
12
11
16
13
14
20
16
14
12
18
–
50
4.6
50
13.6
4.9
6.5
6.4
8.0
4.8
7.4
8.4
7.7
–
50
5.5
5
a
14
23
21
19
21
32
20
21
21
30
–
5
b
9
14.5
4.5
17.0
12.4
4.5
5
c
8
5
d
6
2.6
5
e
6
8.6
7.2
5
f
14
8
15.5
10.2
8.1
17.7
10.0
9.0
5
g
5
h
6
5
i
6
12.4
–
9.0
Gatifloxacin
10
–
–
Amphotericin B
14.0
12.5
15.2
rivatives (5a–5i). Method a. Conventional heating. To a
mixture of a (E)-3-[4-(1H-tetrazol-5-yl)phenyl]-1-phen-
ylprop-2-en-1-one derivative 4a–4i (1 mmol) in DMF
and the reaction mixture was heated at 80–90°C for 7–
8 h. Progress of the reaction was monitored by TLC. Upon
completion of the process, ice cold water was added to the
reaction mixture.Asolid product was filtered off, washed
with water and dried. The crude product was purified by
(5 mL) containing sodium acetate (1 mmol), hydrazine
hydrate (1 mmol), few drops of acetic acid were added,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 9 2019

1908
ASHOK et al.
column chromatography using a mixture EtOAc–hexane
6 : 4 v/v) to afford the corresponding pure product 5a–5i
127.1, 127.7, 129.8, 145.7, 152.5, 156.9. MS: 325 [M +
+
(
H] . Found, %: C 59.10; H 4.01; N 25.81. C H ClN .
1
6
13
6
as a pale yellow solid.
Calculated, %: C 59.17; H 4.03; N 25.88.
Method b. Microwave irradiation. Amixture of a (E)-
5-{4-[3-(4-Bromophenyl)-4,5-dihydro-1H-pyrazol-
–1
3
-[4-(1H-tetrazol-5-yl)phenyl]-1-phenylprop-2-en-1-one
derivative 4a–4i (1 mmol) in DMF (5 mL), sodium acetate
1 mmol), hydrazine hydrate (1 mmol), and few drops of
5-yl]phenyl}-1H-tetrazole (5d). IR spectrum, ν, cm :
1
1624 (C=N), 3325, 3425 (NH). H NMR spectrum, δ,
(
ppm: 3.02–3.09 d.d (1H, J = 8.2 Hz, J = 16.0 Hz, HA),
acetic acid was filled in a quartz tube and inserted into
a Teflon vial with screw cap and exposed to microwave
irradiation at 180W for 8–10 min, with intervals of 30 s.
After completion of the process (TLC), the reaction mix-
ture was poured over crushed ice. The solid thus obtained
was filtered off, washed with water and dried. The crude
product was purified by column chromatography on silica
gel using EtOAc–hexane (6:4 v/v) as an eluent to give the
corresponding pure product 5a–5i as a pale yellow solid.
3.67–3.73 d.d (1H, J = 10.1 Hz, J = 16.0 Hz, H ), 4.95–
B
4.99 m (1H, H ), 7.10 d (2H, J = 7.7 Hz, Ar-H), 7.30 d
X
(2H, J = 7.7 Hz, Ar-H), 7.91 d (2H, J = 8.1 Hz, Ar-H),
8.20 d (2H, J = 8.1 Hz, Ar-H). 13C NMR spectrum, δ,
ppm: 40.1, 61.8, 116.4, 118.6, 119.1, 120.6, 123.5, 125.9,
127.2, 128.1, 129.5, 145.5, 152.9, 158.9. MS: 369 [M +
+
H] . Found, %: C 52.15; H 3.52; N 22.66. C H BrN .
1
6
13
6
Calculated, %: C 52.05; H 3.55; N 22.76.
5
-{4-[3-(p-Tolyl)-4,5-dihydro-1H-pyrazol-5-yl]
–1
5
-[4-(3-Phenyl-4,5-dihydro-1H-pyrazol-5-yl)
phenyl}-1H-tetrazole (5e). IR spectrum, ν, cm : 1619
(C=N), 3315, 3420 (NH). H NMR spectrum, δ, ppm:
–
1
1
phenyl]-1H-tetrazole (5a). IR spectrum, ν, cm : 1624
1
(C=N), 3325, 3425 (NH). H NMR spectrum, δ, ppm:
3.07–3.13 d.d (1H, J = 8.0 Hz, J = 15.8 Hz, H ), 3.47–
A
3
3
.04–3.13 d.d (1H, J = 8.2 Hz, J = 16.0 Hz, H ), 3.57–
3.55 d.d (1H, J = 10.1 Hz, J = 15.8 Hz, H ), 4.93–4.99
A
B
.65 d.d (1H, J = 10.1 Hz, J = 16.0 Hz, H ), 4.93–4.99
m (1H, H ), 7.30–7.44 m (5H , Ar-H), 7.90 d (2H, J =
B
X
13
m (1H, H ), 7.30–7.44 m (5H, Ar-H), 7.90 d (2H, J =
7.8 Hz, Ar-H), 8.04 d (2H, J = 7.8 Hz, Ar-H). C NMR
spectrum, δ, ppm: 26.1, 43.1, 62.8, 114.9, 116.9, 119.0,
119.9, 123.5, 126.9, 127.5, 128.5, 129.8, 146.6, 153.7,
X
1
3
7
.8 Hz, Ar-H), 8.04 d (2H, J = 7.8 Hz, Ar-H). C NMR
spectrum, δ, ppm: 40.1, 61.8, 115.6, 117.6, 119.1, 119.6,
1
MS: 291 [M + H] . Found, %: C 66.18; H 4.85; N 28.64.
+
23.5, 125.9, 127.1, 128.1, 129.8, 145.6, 152.7, 156.9.
157.1. MS: 305 [M + H] . Found, %: C 67.18; H 5.45;
+
N 28.64. C H N . Calculated, %: C 67.09; H 5.30; N
1
7
16
6
C H N O. Calculated, %: C 66.19; H 4.86; N 28.95.
27.61.
16
14
6
5
-{4-[3-(4-Fluorophenyl)-4,5-dihydro-1H-pyrazol-
5-{4-[3-(4-Methoxyphenyl)-4,5-dihydro-1H-pyr-
azol-5-yl]phenyl}-1H-tetrazole (5f). IR spectrum, ν,
cm : 1624 (C=N), 3325, 3425 (NH). H NMR spectrum,
–
1
5
1
-yl]phenyl}-1H-tetrazole (5b). IR spectrum, ν, cm :
620 (C=N), 3325, 3421 (NH). H NMR spectrum, δ,
1
–1
1
ppm: 2.92–3.01 d.d (1H, J = 8.1 Hz, J = 16.2 Hz, HA),
δ, ppm: 3.02–3.09 d.d (1H, J = 8.2 Hz, J = 16.0 Hz, HA),
3
4
7
.67–3.73 d.d (1H, J = 10.2 Hz, J = 16.2 Hz, HB),
3.67–3.73 d.d (1H, J = 10.1 Hz, J = 16.0 Hz, H ), 3.8 s
B
.83–4.90 m (1H, H ), 6.91 d (2H, J = 7.5 Hz, Ar-H),
(3H, OCH ), 4.93–4.99 m (1H, H ), 6.91 d (2H, J = 7.5
X
3
X
.33 d (2H, J = 7.5 Hz, Ar-H), 7.91 d (2H, J = 7.8 Hz,
Hz, Ar-H), 7.33 d (2H, J = 7.5 Hz, Ar-H), 7.84 d (2H,
J = 8.3 Hz, Ar-H), 8.18 d (2H, J = 8.3 Hz, Ar-H). 13
13
Ar-H), 8.10 d (2H, J = 7.8 Hz,Ar-H). C NMR spectrum,
δ, ppm: 40.7, 60.9, 115.4, 117.2, 119.0, 119.9, 123.1,
C
NMR spectrum, δ, ppm: 40.8, 55.1, 61.4, 116.1, 117.7,
1
25.9, 127.1, 128.7, 132.8, 145.5, 153.0, 156.7. 158.1.
119.8, 120.3, 123.0, 125.8, 126.1, 127.4, 129.8, 146.7,
152.5, 156.4. MS: 321 [M + H] . Found, %: C 63.64; H
+
+
MS: 309 [M + H] . Found, %: C 62.31; H 4.21; N 27.20.
C H FN . Calculated, %: C 62.33; H 4.25; N 27.26.
5.23; N 26.01. C H N O. Calculated, %: C 63.74; H
16
13
6
17 16
6
5
.03; N 26.23.
5
-{4-[3-(4-Chlorophenyl)-4,5-dihydro-1H-pyrazol-
–
1
5
1
-yl]phenyl}-1H-tetrazole (5c). IR spectrum, ν, cm :
624 (C=N), 3315, 3422 (NH). H NMR spectrum, δ,
ppm: 3.07–3.19 d.d (1H, J = 8.7 Hz, J = 15.8 Hz, HA),
2-{5-[4-(1H-Tetrazol-5-yl)phenyl]-4,5-dihydro-1H-
1
–1
pyrazol-3-yl}phenol (5g). IR spectrum, ν, cm : 1624
(C=N), 3325, 3425 (NH), 3451 (OH). H NMR spectrum,
1
3
4
.55–3.69 d.d (1H, J = 10.1 Hz, J = 15.8 Hz, H ), 4.90–
δ, ppm: 3.02–3.09 d.d (1H, J = 8.2 Hz, J = 16.0 Hz,
H ), 3.67–3.73 d.d (1H, J = 10.1 Hz, J = 16.0 Hz, H ),
B
.99 m (1H, H ), 6.90 d (2H, J = 7.6 Hz, Ar-H), 7.30 d
X
A
B
(
8
2H, J = 7.6 Hz, Ar-H), 7.81 d (2H, J = 8.1 Hz, Ar-H),
.04 d (2H, J = 8.1 Hz, Ar-H). 13C NMR spectrum, δ,
ppm: 40.8, 61.4, 115.1, 117.0, 119.1, 119.3, 123.0, 125.9,
4.93–4.99 m (1H, H ), 6.90 d (2H, J = 7.6 Hz, Ar-H),
7.30 d (2H, J = 7.6 Hz, Ar-H), 7.64 d (2H, J = 8.1 Hz,
Ar-H), 8.04 d (2H, J = 8.1 Hz, Ar-H), 11.13 s (1H, -OH).
X
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 9 2019

MICROWAVE ASSISTED SYNTHESIS
1909
13C NMR spectrum, δ, ppm: 40.8, 61.6, 115.7, 116.6,
the experiments were carried out in triplicates, and the
results were expressed as zone of inhibition in mm. The
zones of inhibition of compounds 5a–5i were compared
with those of the standard antibiotic gatifloxacin (10 and
20 ꢀg/mL).
1
19.1, 119.3, 123.0, 125.9, 127.1, 127.7, 129.8, 145.6,
52.6, 156.8. MS: 307 [M + H] . Found, %: C 62.68; H
+
1
4
4
.55; N 27.34. C H N O. Calculated, %: C 62.74; H
1
6
14
6
.61; N 27.44.
5
-{4-[3-(3-Chlorophenyl)-4,5-dihydro-1H-pyrazol-
Antifungal activity. Antifungal activity of compounds
5a–5i was tested against three pathogenic fungi, namely
Aspergillus Niger, Aspergilus flavus, and Fusarium oxys-
porum by the poison plate technique at a concentration of
50 ꢀg/mL. Three kinds of fungi were incubated in PDA
at 25±1°C for 5 days to get new mycelium for antifungal
assay, then mycelium as discs of approximately 0.45 cm
diameter were cut from the culture medium, picked up
with a sterilised inoculation needle and inoculated in the
center of PDA plate. Test compounds were dissolved in
DMSO (10 mL) and added into the potato dextrose agar
medium (PDA, 90 mL). The final concentration of com-
pounds in the medium was adjusted to 50 ꢀg/mL. The
inoculated plates were incubated at 25±1°C for 5 days.
Acetone was diluted with sterilised distilled water and
used as a control, while clotrimazole (50 ꢀg/mL) was used
as a standard control for each treatment. The experiments
were carried out in triplicates. The radial growth of the
fungal colonies was measured on the 5th day.
–
1
5
1
-yl]phenyl}-1H-tetrazole (5h). IR spectrum, ν, cm :
614 (C=N), 3325, 3435 (NH). H NMR spectrum, δ,
ppm: 3.00–3.11 d.d (1H, J = 8.3 Hz, J = 16.5 Hz, HA),
.55–3.69 d.d (1H, J = 10.1 Hz, J = 16.5 Hz, H ), 4.75–
.83 m (1H, H ), 6.79–7.23 m (4H, Ar-H), 7.84 d (2H,
J = 8.3 Hz, Ar-H), 8.18 d (2H, J = 8.3 Hz, Ar-H). 13C
NMR spectrum, δ, ppm: 41.1, 63.4, 116.1, 117.0, 119.1,
19.9, 123.0, 125.9, 126.7, 127.7, 129.8, 145.7, 153.5,
1
3
4
B
X
1
1
+
56.9. MS: 325 [M + H] . Found, %: C 59.10; H 4.01;
N 25.81. C H ClN . Calculated, %: C 59.17; H 4.03;
N 25.88.
16
13
6
5-{4-[3-(3-Bromophenyl)-4,5-dihydro-1H-pyrazol-
–
1
5
1
-yl]phenyl}-1H-tetrazole (5i). IR spectrum, ν, cm :
624 (C=N), 3325, 3415 (NH). H NMR spectrum, δ,
ppm: 3.02–3.09 d.d (1H, J = 8.2 Hz, J = 16.0 Hz, HA),
.67–3.73 d.d (1H, J = 10.1 Hz, J = 16.0 Hz, H ), 4.95–
.99 m (1H, H ), 6.77–7.27 m (4H, Ar-H), 7.97 d (2H,
J = 8.1 Hz, Ar-H), 8.20 d (2H, J = 8.1 Hz, Ar-H). 13C
1
3
4
B
X
NMR spectrum, δ, ppm: 40.1, 61.8, 116.4, 118.6, 119.1,
CONCLUSIONS
1
1
20.6, 123.5, 125.9, 127.2, 128.1, 129.5, 145.5, 152.7,
56.9. MS: 369 [M + H] . Found, %: C 52.15; H 3.52;
A new series of 5-[4-(3-phenyl-4,5-dihydro-1H-pyr-
azol-5-yl)phenyl]-1H-tetrazole derivatives is synthesized
under conventional and microwave irradiation methods.
Under MWI conditions the reaction time was much
shorter leading to higher yields of products than under
conventional conditions. The synthesized compounds are
tested in vitro for determining their antimicrobial activity.
The compound 5f was found to be equipotent with the
standard drug gatifloxacin. The compounds 5b and 5f
exhibit the promising activity against pathogenic fungi.
+
N 22.66. C H BrN . Calculated, %: C 52.05; H 3.55;
16
13
6
N 22.76.
Antibacterial activity. The synthesized compounds
a–5i were tested for their antibacterial activity against
5
bacterial strains including gram-negative Klebsiella pneu-
monia and Escherichia coli and gram-positive Bacillus
subtilis and Staphylococcus aeureus at concentrations
of 10 and 20 ꢀg/mL. The cultures were diluted with 5%
saline, autoclaved, and the final volume was adjusted
5
6
FUNDING
(
concentration ca 10 –10 CFU/mL). The synthesized
compounds were diluted by DMSO for antibacterial
biological assays. For agar disc diffusion method, the
liquid form of a test compound was soaked on to the disc
and then allowed to air dry, to make the disc completely
saturated with the test compound. The saturated by a
chemical disc was introduced onto the upper layer of the
medium evenly flooded with the bacteria. The disc was
dipped in different chemical samples, placed over the
evenly spread bacterial nutrient media and incubated at
The authors are thankful to The Head, Department of
Chemistry, Osmania University for providing laboratory
facilities and the Director, Central Facilities for Research
and Development (CFRD), Osmania University for pro-
viding IR and NMR spectral analysis. We are thankful to
the University Grants Commission, New Delhi, for their
financial support. D. Ashok is thankful to UGC, New
Delhi for the award of UGC-BSR fellowship.
CONFLICT OF INTEREST
37°C for 24–48 h for more efficient inhibition of bacteria.
The zones of inhibition were measured after 24–48 h.All
No conflict of interest was declared by the authors.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 9 2019

1910
ASHOK et al.
6. Bhat, B.A., Dhar, K.L., Puri, S.C., Saxena, A.K.,
REFERENCES
Shanmugavel, M., and Qazi, G.N., Bioorg. Med.
Chem. Lett., 2005, vol. 15(12), p. 3177.
1
. Ostrovskii, V.A., Koldobskii, G.I., and Trifonov, R.E.,
Comprehensive Heterocycl. Chem. III, 2008, vol. 6,
p. 257.
https://doi.org/10.1016/j.bmcl.2005.03.121
https://doi.org/10.1016/B978-008044992-0.00517-4
7
8
. Uchida, H., Tanikoshi, H., Nakamura, S., Reddy, P.Y.,
and Toru, T., Synlett., 2003, vol. 8, p. 1117.
https://doi.org/10.1055/s-2003-39906
2
3
4
. Ashok,D.,Ganesh,A.,Ravi,S.,Lakshmi,B.V.,andRamesh,
B., Russ. J. Gen. Chem., 2014, vol. 84, p. 2248.
https://doi.org/10.1134/S1070363214110346
. Azarifar, D. and Shaebanzadeh, M., Molecules., 2002.
vol. 7(12), p. 885.
https://doi.org/10.3390/71200885
. Adib, M., Mahdavi, M., Mahmoodi, N., Pirelahi, H.,
and Bijanzadeh, H.R., Synlett., 2006, vol. 11,
p. 1765.
. Shoman, M.E., Abdel Aziz, M., Aly, O.M., Farag, H.H.,
and Morsy, M.A., Eur. J. Med. Chem., 2009, vol. 44,
p. 3068.
https://doi.org/10.1055/s-2006-944200
9
. Ashok, D., Madhuri, E.L., Sarasija, M., Sree Kanth, S.,
Vijjulatha, M., Malini Alaparthi, D., and Sagurthi, S.R.,
RSC Adv., 2017, vol.7, p. 25710.
https://doi.org/10.1016/j.ejmech.2008.07.008
5
. Barsoum, F.F., Hosni, H.M., and Girgis, A.S.,
Bioorg. Med. Chem., 2006, vol. 14, p. 3929.
https://doi.org/10.1016/j.bmc.2006.01.042
https://doi.org/10.1039/c7ra01550j
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 9 2019