Microwave assisted synthesis, characterization, molecular docking, antiinflammatory and analgesic activity of acylhydrazones bearing thiophene moiety

Article abstract of DOI:10.14233/ajchem.2017.20785

NSAIDS are the first drug of choice in the treatment of inflammation has several side effects and still there is a need to introduce a new effective agent. In the present study, N-acylhydrazones bearing thiophene moiety were synthesized by applying bioiso

Full text of DOI:10.14233/ajchem.2017.20785

Asian Journal of Chemistry; Vol. 29, No. 11 (2017), 2479-2484
ASIAN JOURNAL OF CHEMISTRY
https://doi.org/10.14233/ajchem.2017.20785
Microwave Assisted Synthesis, Characterization, Molecular Docking,
Antiinflammatory and Analgesic Activity of Acylhydrazones Bearing Thiophene Moiety
2
M. SOUJANYA1,* and G. RAJITHA
1Department of Pharmaceutical Chemistry, Gokula Krishna College of Pharmacy, SPSR Nellore-524 121, India
2Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Technology, Sri Padmavathi MahilaVisvavidyalayam (Mahila University),
Tirupati-517 502, India
*Corresponding author: E-mail: soujipharma@gmail.com
Received: 17 May 2017;
Accepted: 17 August 2017;
Published online: 29 September 2017;
AJC-18576
NSAIDS are the first drug of choice in the treatment of inflammation has several side effects and still there is a need to introduce a new
effective agent. In the present study, N-acylhydrazones bearing thiophene moiety were synthesized by applying bioisosterism drug design
tool, characterized, screened for anti-inflammatory, analgesic activity and molecular docking using GLIDE. All the compounds viz.,
2-benzamido-N’-(substituted)-3-(thiophen-2-yl)acrylohydrazides (4a-l) were synthesized by the microwave irradiation of compound
2-(benzamido)-3-(thiophen-2-yl)acrylohydrazide (3) with different aromatic/heteroaromatic aldehydes in acidic conditions by microwave
irradiation and characterized by IR, 1H & 13C NMR, Mass spectra, followed by elemental analysis. Compound 4j showed slightly superior
anti-inflammatory and analgesic activity (76 and 64 %) than standard (73 %, 62 %). The above results were supported by molecular
docking studies done by using COX-2 protein revealed, compound (4j,4d) have -9.77, -9.58 as docking score which is higher than
standard (-7.18). The present study concludes the potentiality of acylhydrazones to further developed as effective anti-inflammatory
agents.
Keywords: Acylhydrazones, Anti-inflammatory activity, Analgesic activity, Molecular docking, Bioisosterism.
with thiophene and screened for anti-inflammatory, analgesic
INTRODUCTION
and molecular docking studies against COX-2 protein (pdb
Inflammation is the complex defense mechanism of body
code: 5F19).
in different pathological such as arthritis, asthma, inflammatory
bowel diseases. The therapeutic option for the treatment of
EXPERIMENTAL
inflammation is the conventional NSAIDS but suffers with
the gastric pain [1] and cardiac toxicity [2]. So there is a signi-
ficant need for the development of safer drug, which is devoid
from classical side effects. On the other hand hydrazones are
the versatile molecule has wide range of biological activities
viz. antimicrobial [3], anti-inflammatory [4,5], antitubercular
[6,7], anticancer [8], anti HIV [9], analgesic [10], antiamoebic
[11] etc. Particularly hydrazone moiety attached to heterocyclic
systems was shown to offer enhanced activity [12] and also the
heterocyclic system plays an important role in drug develop-
ment of anti-inflammatory agents [13]. This is achieved by the
application of bioisosterism, one of the powerful drug design
tool includes the exchange of one of bioisoster with the other
to modify the activity profile of lead compound. Against the
above background it has been planned to synthesize new acyl-
hydrazone derivatives from the N-(α-acetamido cinnamoyl)-
arylhydrazones [14] by the bioisosteric replacement of phenyl
All the melting points reported in this series were deter-
mined in open capillaries usingThermonik Pricision Melting Point
Cum Boiling Point Apparatus C-PMB and are uncorrected.
Homogeneity of the compounds was checked by using pre
coated TLC plates. The IR spectra were recorded using KBr
1
pellets on a Perkin-Elmer 1760 Spectrophotometer. H, 13C
NMR spectra were recorded on BrukerAdvance/Jeol 400 MHz
spectrophotometer, using tetra methyl saline as internal
standard. Mass spectra were recorded on anApex Mass spectro-
photometer, elemental analyses were performed on Flash
EA1112 CHNS analyzer and microwave irradiation was
carried out in a domestic microwave oven (LGMS, 2.45 MHz).
All the solvents and chemicals were procured from Sigma
Aldrich and used without purification.
Synthesis of 2-Phenyl-4-[(thiophen-2-yl)methylene]
oxazol-5-one (2): Synthesis of 2-phenyl-4-[(thiophen-2-yl)-

2480 Soujanya et al.
Asian J. Chem.
methylene]oxazol-5-one was done accordance with the pre-
viously reported method [15].
Ar C-H, HC=C), 8.32 (s, 1H, HC=N), 9.91 (s, 1H, CO-NH),
11.54 (s, 1H, CO-NH-N); Anal. calcd. for C24H23N3O5S (%):
C, 61.53; H, 5.13; N, 8.55. Found: C, 61.70; H, 5.21; N, 8.37.
2-Benzamido-N’-(4-dimethylaminobenzylidene)-3-
(thiophen-2-yl) acrylohydrazide (4e): Yield: 79 %; m.p.: 202-
204 °C; IR (KBr, νmax, cm–1): 3271 (N-H), 3076 (Ar C-H), 2810
(-CH3), 1653 (C=O), 1576 (C=N); 1H NMR (400 MHz, DMSO-
d6) δ: 2.69 (s, 6H, N-(CH3)2), 6.95-7.97 (m, 13H,Ar C-H, HC=C),
8.29 (s, 1H, HC=N), 9.87 (s, 1H, CO-NH), 11.49 (s, 1H, CO-NH-
N); Anal. calcd. for C23H22N4O2S (%): C, 67.54; H, 5.44; N,
12.60. Found: C, 67.83; H, 5.52; N, 12.80.
2-Benzamido-N’-(4-chlorobenzylidene)-3-(thiophen-2-
yl) acrylohydrazide (4f): Yield: 77 %; m.p.: 238-240 °C; IR
(KBr, νmax, cm–1): 3269 (N-H), 3062 (Ar C-H), 1662 (C=O),
1571 (C=N); 1H NMR (400 MHz, DMSO-d6) δ: 7.16 (s, 1H,
HC=C), 7.07-8.21 (m, 13H, Ar C-H, HC=C), 8.40 (s, 1H,
HC=N), 9.92 (s, 1H, CO-NH), 11.51 (s, 1H, CO-NH-N);Anal.
calcd. for C21H18N3O2SCl (%): C, 61.37; H; 4.16; N, 9.64. Found:
C, 63.25; H; 4.34; N, 9.76.
2-Benzamido-N’-(4-nitrobenzylidene)-3-(thiophen-2-
yl) acrylohydrazide (4g):Yield: 80 %; m.p.: 246-248 °C; IR
(KBr, νmax, cm–1): 3268 (N-H), 3061 (Ar C-H), 1655 (C=O),
1568 (C=N), 1525, 1317 (NO2); 1H NMR (400 MHz, DMSO-
d6) δ: 7.14-8.30 (m, 13H,Ar C-H, HC=C), 8.54 (s, 1H, HC=N),
9.98 (s, 1H, CO-NH), 11.80 (s, 1H, CO-NH-N); Anal. calcd.
for C21H16N4O4S (%): C, 59.87; H, 4.06, N, 13.55 Found: C,
59.54; H, 4.25; N, 13.62.
Synthesis of 2-(benzamido)-3-(thiophen-2-yl)-acylo-
hydrazide (3): 2-Phenyl-4-((thiophen-2-yl)methylene)oxazol-
5-one (2, 0.01 mmol) was stirred with a solution of hydrazine
hydrate (0.02 mmol) in ethanol (20 mL) for 30 min. The deep
yellow colour of oxazolone immediately changed to light yellow
colour product, which was filtered, washed, used in next step
[16]. Yield: 79 %; m.p.: 155-157 °C; IR (KBr, νmax, cm–1):
3228, 3242 (NH2), 3073 (Ar C-H) 1651 (C=O), 1573 (C=N);
1H NMR (400 MHz, DMSO-d6) δ: 4.45 (s, 2H, NH2), 6.98-
7.99 (m, 9H, Ar C-H, HC=C), 9.73 (s, 1H, CO-NH-C), 10.66
(s, 1H, CO-NH-N);Anal. calcd. for C14H13N3O2S(%): C, 58.52;
H, 4.56, N, 14.62. Found: C, 58.17; H, 4.24; N, 17.53.
General procedure for the synthesis of 2-benzamido-N’-
(substituted)-3-(thiophen-2yl)acrylohydrazide (4a-l):
Equimolar ratios of α-benzamido-(4-nitro)-cinnamal-hydrazide
and different benzaldehydes (0.01 mol) in absolute ethanol
with a few drops of glacial acetic acid were transferred in to
reaction flask and allowed to microwave irradiation at 160
watts with 15 s of interval for about 60-180 s. The reaction
was monitored by TLC and the mixture was allowed to cool at
room temperature, filter and purified by recrystallization from
methanol. The physical data of all the title compounds were
given below:
2-Benzamido-N’-(benzylidene)-3-(thiophen-2-yl)acrylo-
hydrazide (4a): Yield: 71 %; m.p.: 210-212 °C; IR (KBr, νmax
,
cm–1): 3290 (N-H), 3103 (Ar C-H), 1637 (C=O), 1567 (C=N);
1H NMR (400 MHz, DMSO- d6) δ: 7.09-8.11 (m, 14H, Ar C-
H, HC=C), 8.42 (s, 1H, HC=N), 9.93 (s, 1H, CO-NH), 11.59
(s, 1H, CO-NH-N); 13C NMR (100 MHz, DMSO-d6): δ 115,
127, 128, 129, 130, 132, 133, 147, 163, 165. EI-MS m/z; 375
(M+). Anal. calcd. for C21H17N3O2S (%): C, 67.18; H, 4.56; N,
11.19. Found: C, 67.34; H, 4.64; N, 11.22.
2-Benzamido-3-(thiophen-2-yl)-N’-[(thiophen-2-yl)
methylene]acrylohydrazide (4h): Yield: 82 %; m.p.: 228-
230 °C; IR (KBr, νmax, cm–1): 3273 (N-H), 3026 (Ar C-H),
1659 (C=O), 1542 (C=N); 1H NMR (400 MHz, DMSO-d6) δ:
7.09-8.06 (m, 12H,Ar C-H, HC=C), 8.08 (s, 1H, HC=N), 9.90
(s, 1H, CO-NH), 11.51 (s, 1H, CO-NH-N); Anal. calcd. for
C19H15N3O2 S2 (%): C, 59.82; H, 3.96; N, 11.02. Found: C,
58.53; H, 3.65; N, 11.35.
2-Benzamido-N’-[(pyridin-4yl)methylene]-3-(thiophen-
2-yl)acrylohydrazide (4i):Yield: 78 %; m.p.: 185-187 °C; IR
(KBr, νmax, cm–1): 3223 (N-H), 3043 (Ar C-H), 1645 (C=O),
1543 (C=N); 1H NMR (400 MHz, DMSO-d6) δ: 7.10-8.59 (m,
13H, Ar C-H, HC=C), 8.38 (s, 1H, HC=N), 9.94 (s, 1H, CO-
NH), 11.82 (s, 1H, CO-NH-N); Anal. calcd. for C20H16N4O2S
(%): C, 63.81; H, 4.28; N, 14.88. Found: C, 63.49; H, 4.41; N,
14.72.
2-Benzamido-N’-(indol-3-yl-methylene)-3-(thiophen-2-
yl)acrylohydrazide (4j): Yield: 75 %; m.p.: 235-237 °C; IR
(KBr, νmax, cm–1): 3475 (N-H of Ind), 3252 (N-H), 3053 (Ar
C-H), 1673 (C=O), 1572 (N=C); 1H NMR (400 MHz, DMSO-d6)
δ: 6.70-8.13 (m, 14H, Ar C-H, HC=C), 8.43 (s, 1H, HC=N),
10.81 (s, 1H, CO-NH-), 10.21 (s, 1H, NH of Ind), 11.09 (s,
1H, CO-NH-N);13C NMR (100 MHz, DMSO-d6) δ: 111, 112,
115, 120, 126, 127, 128, 129, 130, 132, 135, 137, 144, 162, 165.
EI-MS m/z; 414 (M+); Anal. calcd. for C23H18N4O2S (%): C,
66.65; H, 4.38; N, 13.52. Found: C, 66.24; H, 4.68; N, 13.49.
2-(Benzamido)-N’-(2-oxoindolin-3-ylidene)-3-(thiophen-
2-yl)acrylohydrazide (4k): Yield: 69 %; m.p.: 231-233 °C;
IR (KBr, νmax, cm–1): 3470 (N-H of Isa), 3238 (N-H), 3063
(Ar C-H), 1725, 1675 (C=O of isa, C=O of CONH); 1H NMR
(400 MHz, DMSO-d6) δ: 6.6-8.14 (m, 13H, Ar C-H, HC=C),
2-Benzamido-N’-(4-methoxybenzylidene)-3-(thiophen-
2-yl)acrylohydrazide (4b): Yield: 68 %; m.p.: 220-222 °C;
IR (KBr, νmax, cm–1): 3255 (N-H), 3068 (Ar C-H), 2836
1
(-OCH3), 1640 (C=O), 1577 (C=N); H NMR (400 MHz,
DMSO-d6) δ 3.76 (s, 3H, Ar-OCH3), 6.96-8.08 (m, 13H, Ar
C-H, HC=C), 8.33 (s, 1H, HC=N), 9.89 (s, 1H, CO-NH), 11.42
(s, 1H, CO-NH-N);Anal. calcd. for C22H19N3O3S (%): C, 65.18;
H, 4.56; N, 11.19. Found: C, 65.33; H, 4.41; N, 11.53.
2-Benzamido-N’-(4-hydroxy-3-methoxybenzylidene)-
3-(thiophen-2-yl)acrylohydrazide (4c) Yield: 70 %; m.p.:
230-232 °C; IR (KBr, νmax, cm–1): 3362 (Ar-OH) 3266 (N-H),
2997 (Ar C-H), 2841 (-OCH3), 1647 (C=O), 1597 (C=N); 1HNMR
(400 MHz, DMSO-d6) δ: 3.66 (s, 3H, Ar-OCH3), 6.91-8.07
(m, 12H, Ar C-H, HC=C), 8.41 (s, 1H, HC=N), 9.60 (s, 1H,
Ar-OH), 9.90 (s, 1H, CO-NH), 11.50 (s, 1H, CO-NHN); 13C NMR
(100 MHz, DMSO-d6) δ: 55.2, 113, 116, 122, 125, 126, 127,
128, 130, 133, 137, 144, 148, 149, 163, 166. EI-MS m/z; 421
(M+). Anal. calcd. for C22H19N3O4S (%): C, 62.69; H, 4.54; N,
9.97. Found: C, 62.51; H, 4.34; N, 9.82
2-Benzamido-N’-(3, 4, 5-trimethoxybenzylidene)-3-
(thiophen-2-yl)acrylohydrazide (4d):Yield: 74 %; m.p.: 164-
166 °C; IR (KBr, νmax, cm–1): 3194 (N-H), 3060 (Ar C-H),
2837 (-OCH3), 1660 (C=O), 1572 (C=N); 1H NMR (400 MHz,
DMSO-d6) δ: 3.66-3.786 (s, 6H,Ar-OCH3), 6.95-8.08 (m, 14H,

Vol. 29, No. 11 (2017)
Microwave Assisted of Acylhydrazones Bearing Thiophene Moiety 2481
10.78 (s, 1H, NH of Isa), 10.07 (s, 1H, CO-NH), 11.08 (s, 1H,
CO-NH-N);Anal. calcd. for C22H16N4O3S (%): C, 63.45; H, 3.87;
N, 13.45. Found: C, 63.54; H, 3.83; N, 13.59.
structure of aforementioned compounds (4a-l) were drawn
using chem 3D ultra 12.0 software (Cambridge soft corporation)
and the druglikness scores for all ligands were evaluated with
the help of Lipinski filter. Subsequently, the optimized ligands
and standard drug were embedded in to the generated grid of
human COX-2 protein to access their binding affinities and
dock score using GLIDE XP docking score method.
2-(Benzamido)-N’-[(naphthalen-3-yl)methylene]-3-
(thiophen-2-yl)acrylohydrazide (4l):Yield: 70 %; m.p.: 181-
183 °C; IR (KBr, νmax, cm–1): 3186 (N-H), 3049 (Ar C-H),
1647 (C=O), 1576 (C=N); 1H NMR (400 MHz, DMSO-d6) δ:
7.16 (s, 1H, HC=C), 7.10-8.11 (m, 16H, Ar C-H, HC=C), 8.7
(s, 1H, HC=N), 9.95 (s, 1H, CO-NH), 11.63 (s, 1H, CO-NH-
N); Anal. calcd. for C25H19N3O2S (%): C, 70.57; H, 4.50; N,
9.88. Found: C, 70.19; H, 4.68; N, 9.85.
in vivo Antiinflammatory activity: The in vivo anti-
inflammatory activity of all the title compounds was evaluated
using carrageenan-induced hind paw edema test in male albino
rats (150-180 g) of Wistar strain at 100 mg/kg body weight
[17]. The rats were divided into groups of six animals. Control
group received 0.5 % sodium carboxymethyl cellulose, the
standard group received standard drug indomethacin 5 mg/kg
body weight and the test groups received the synthesized com-
pounds at the dose of 100 mg/kg body weight. The volume of
the injected paw was measured by plethysmograph imme-
diately after carrageenan injection. The paw volume was again
measured after 3 h. A mark was made at the lateral maleolus
and the foot was dipped to the same distance into the arm of
plethysmograph. Average edema volumes for test compound
treated and positive control rats were compared statistically and
expressed as the pre cent edema inhibition, which was calculated
using the formula.
RESULTS AND DISCUSSION
2-Benzamido-N’-(substituted benzylidene)-3-(thiophen-
2-yl)acrylohydrazides (4a-l) were synthesized by the nucleo-
philic addition of 2-(benzamido)-3-(thiophen-2-yl)acrylo-
hydrazide (3) with aromatic aldehydes and simultaneous
elimination of water by microwave irradiation (160 watts) under
acidic conditions with less reaction time (30-180 s), high purity
and yields (68-82 %), depicted in Scheme-I. Compound 3
has been synthesized from intermediate compound 2 by the
action of hydrazine hydrate, act as strong nucleophile attacks
the oxazole ring at highly susceptible carbonyl site. Compound
2 was prepared according to literature procedure. The IR
spectral data of title compounds 4a-l showed strong bands
between 3475–3186 cm–1and 1675-1637 cm–1 due to the presence
of NH and C=O peaks, respectively and also appearance of
two more bands between 3103-2997 cm–1, 1577-1542 cm–1
region indicates the presence of aromatic C-H, N=CH groups
in title compounds. This was further confirmed by 1H NMR spectra
explains the appearance of a new singlet around δ 8.0 region
(which corresponds to CH=N proton), in the place of singlet
at δ 4.45 (due to free NH2 in compound 3) clearly indicates
the formation of title compounds. This was supported by the
appearance of singlet between of δ 11.09-11.82 region due to
the protons of -CONH-N= group (hydrazone) and showed a multi-
plet between δ 6.70-8.21 regions indicates the shielding and
deshielding of aromatic protons by substituents on ring.Additional
support for the structures of title compounds was provided by
13C NMR spectra reveals two peaks around δ 163-166 and a peak
around δ 55 assigned for carbonyl group of amide and methoxy
group respectively. The peaks resonated between δ 111-149
is due to the presence of aromatic/hero-aromatic carbons and
also appearance of signal around δ 140 indicates the presence
of C=N linkage. All the title compounds conformed by the
appearance of molecular ion peaks between m/z 375-421.
Antiinflammatory activity:All the compounds (4a-l) eva-
luated for the antiinflammatory activity by carrageenan induced
rat paw edema method and the activity profile clearly indicates
the type of substitution at the hydrazone end of the molecule
significantly alters the activity follows such as fused heteroaryl
> phenyl with EDG > phenyl > polycyclic moiety > six mem-
bered hetero aryl > phenyl with EWG > five membered heteroaryl
substitutions (Table-1). It is also observed that among all com-
pound (4j) elicited superior activity than standard, is due to the
presence of additional electron rich heterocyclic ring within the
molecule [12] followed by compounds (4c and 4d) due to the
presence of more number of EDGs at the hydrazide end of the
molecule responsible for the enhanced activity [19]. It is important
to note, as increase the number of EDGs on phenyl ring enhance
the activity (4d > 4b) and this observation gave additional support
for the importance of EDGs towards the activity.
Inhibition (%) = 100 (1-Vt/V c)
(1)
where, Vc = volume of edema in the control group and Vt =
volume of edema in the treated group. Statistical significance
of the results was tested by Dunnet’s test.
Analgesic activity by acetic acid induced writhing
method: This method was based on acetic acid-induced writhings
in mice [18]. Albino mice of both sex (18-25 g) were used. The
animals were divided into groups consisting of six mice each
and control group received 0.5 % sodium carboxy methyl-
cellulose. Test groups were dosed with the test compounds and
the standard group with aspirin, at a dose of 100 mg/kg p.o., 1 h
before intraperitoneal injection of 0.6 % acetic acid (10 mL/
kg). Mice were observed for the total number of writhes for a
period of 15 min beginning 5 min after the acetic acid injection
and the total number of writhes was recorded. The mean value
of writhes for each group was calculated and compared
statistically with the vehicle treated control group. Results were
expressed in terms of percent inhibition of the number of
writhes, which was calculated using the formula:
Inhibition (%) = 100(1-Wt/Wc)
(2)
where, Wc number of writhes for the control group and Wt
number of writhes for the treated group. Statistical significance
of the results was tested by Dunnet’s test.
Molecular docking: Molecular docking of compounds
(4a-l) with 3D X-ray crystal structure of human COX-2 retrieved
from the Protein data bank (PDB code: 5F19) was imported
in to maestro v 9.0. All the bound water, ligands were elimi-
nated from the protein and receptor grid of 20 × 20 × 20 Å
was generated around the active site using PyMOL. The 3D

2482 Soujanya et al.
Asian J. Chem.
O
O
Cl
HO
N
H
H
N
O
2
S
OH
O
STEP 1
O
(1)
a
STEP 2
O
S
NH2NH2
R
O
S
O
NH
b
O
c
STEP 3
STEP 4
HN
O
NH
2
S
N
NH
O
NH
R
N
O
(4a-4l)
(2)
(3)
(a): (CH3CO)2 O/zinc oxide and ethanol; (b) : Absolute ethanol, stirring; (c): MW at 160 W
R=Phenyl (4a); 4-Methoxy phenyl (4b); 4-Hydroxy, 3-methoxy phenyl (4c); 3,4,5-Trimethoxy phenyl (4d); 4-Dimethyl amino phenyl(4e);
4-Chloro phenyl (4f); 4-Nitro phenyl (4g); Thiophen-2-yl (4h); Pyridin-4-yl (4i); Indol-3-yl (4j); Isatin-3-yl (4k); Naphthalen-2-yl (4l)
Scheme-I: General sequence of reactions for the synthesis of compounds (4a-l)
TABLE-1
in vivo ANTI-INFLAMMATORY ACTIVITY AND MOLECULAR DOCKING SCORES OF TITLE COMPOUNDS (4a-l)
in vivo
Molecular docking
AA
Compd.
No.
Edema
Edema
NHB
HBD (Å)
DS
BE (Kcal/mol)
volume ( SD)a
0.17 (0.14)c
0.15(0.04)b
0.13(0.02)c
0.13(0.02)b
0.25 (0.05)b
0.26(0.17)b
0.31 (0.25)c
0.35(0.22)b
0.25(0.25)c
0.12(0.01)c
0.15(0.09)c
0.16(0.06)b
0.14(0.02)c
inhibition (%)d
67*
69*
74*
73*
48
46
39
27
51
76*
70*
66*
73*
2
–
2
1
1
1
1
1
1
1
2
–
0
2.17, 2.06
–
GLN203, HIE388
–
-7.58
-7.02
-8.96
-9.58
-6.87
-7.08
-6.63
-6.97
-7.92
-9.77
-7.94
-7.20
-7.18
-58.07
-50.10
-75.15
-75.72
-73.46
-81.88
-72.72
-56.03
-69.86
-70.01
-70.16
-64.69
-37.19
4a
4b
4c
4d
4e
4f
2.00, 2.31
2.08
2.63
2.06
2.43
2.21
2.04
2.23
2.01
–
GLN454
GLN454
HIE388
HIE388
HIE388
HIE388
HIS214
HIE388
ASN382, HIE388
–
4g
4h
4i
4j
4k
4l
–
–
Std
Significant levels *p < 0.001 by Dunnet’s t- test; aEdema volume was measured 3 h after carrageenan injection and expressed as mean standard
deviation; Control edema volume = 0.48 0.04; Control edema volume = 0.52 0.01; At 100 mg/kg (p.o) per cent edema inhibition was
calculated by comparing edema volume with that of the respective control animals; NHB: No of hydrogen bonds; HD: Hydrogen bond distance;
AA: Amino acid; DS: Docking score; BE: Binding free energy
b
c
d
Molecular docking: All the title compounds (4a-l) were
docked into COX-2 (PDB code: 5F19) protein. Docking studies
reveals, the aromatic substitution at the hydrazide end and
thiophene moiety responsible for fitting of ligand in to the
hydrophobic cavity of target and also the carbonyl group,
substitutions on the aromatic ring responsible for hydrogen
bond formation with the target illustrated in Fig. 1. The results
(Table-1) revealed that all the compounds showed good binding
affinity towards the target except few (4e, 4g, 4h) and com-
pound (4j: -9.77) showed highest docking score than standard
(-0.718), forms one hydrogen bond (2.23 Å) with the HIS 388
amino acid present at the active site of target protein (Figs. 2
and 3). It is interesting to note that all the compounds bind
with the target protein in cis conformation except 4a, 4c,4d
(trans conformation) and form hydrogen bond between C=O
of ligand with the HIE 388 amino acid of target protein. And
also compounds (4c and 4d) form two hydrogen bond inter-
actions with GLN454 amino acid of target protein is due to
the terminal EDGs, which influences the biological activity
significantly.
Analgesic activity: Further the study was extended by
screening of active antiinflammatory compounds (4a, 4b, 4c,

Vol. 29, No. 11 (2017)
Microwave Assisted of Acylhydrazones Bearing Thiophene Moiety 2483
TABLE-2
in vivo ANALGESIC ACTIVITY OF COMPOUNDS 4a-l
Number of writhes in
15 min ( SD)a
Writhing inhibition
in (%)c
Compd. No.
responsible for fitting into
hydropholic cavity of target
O
55 ( 16)
58 ( 15)
34 ( 04)
42 ( 12)
28 ( 02)
33 ( 05)
30 ( 02)
29
26
4a
4b
4c
O
N H
responsible for hydrogen
bond formation with target
56*
46*
64*
58*
62*
S
N
NH
4d
4j
4k
Std
R
responsible for π−π staking
interaction with target
Significant levels *p < 0.001 by Dunnet’s t- test; aNumber of writhes
in 15 min beginning 5 min after acetic acid injection and expressed as
mean standard deviation; bControl number of writhes = 78 ( 2); cAt
100 mg/kg Per cent writhing inhibition was calculated by comparing
number of writhes with that of the respective control animals.
Fig. 1. Interaction sites of title compounds with COX-2 protein
Conclusion
In conclusion, we have synthesized the title compounds
by using microwave technique with less reaction time, good
yields, screened for the antiinflammatory and analgesic activity.
Among all the compounds, compound 4j emerged as a lead
compound have both antiinflammatory and analgesic activity
which is supported by molecular docking studies and also need
further studies to optimize the molecule as effective drug candidate.
REFERENCES
1. M.C. Allison, A.G. Howatson, C.J. Torrance, F.D. Lee and R.I. Russell,
N. Engl. J. Med., 327, 749 (1992);
https://doi.org/10.1056/NEJM199209103271101.
2. P. McGettigan and D. Henry, JAMA, 296, 1633 (2006);
https://doi.org/10.1001/jama.296.13.jrv60011.
3. A.M. Pieczonka,A. Strzelczyk, B. Sadowska, G. Mloston and P. Staczek,
Eur. J. Med. Chem., 64, 389 (2013);
Fig. 2. Interaction of 4j with COX-2
https://doi.org/10.1016/j.ejmech.2013.04.023.
4. M. Gokce, S. Utku and E. Kupeli, Eur. J. Med. Chem., 44, 3760 (2009);
https://doi.org/10.1016/j.ejmech.2009.04.048.
5. C.M. Moldovan, O. Oniga, A. Parvu, B. Tiperciuc, P. Verite, A. Pirnau,
O. Crisan, M. Bojita and R. Pop, Eur. J. Med. Chem., 46, 526 (2011);
https://doi.org/10.1016/j.ejmech.2010.11.032.
6. E.Vavrikova, S. Polanc, M. Kocevar, K. Horvati, S. Bosze, J. Stolarikova,
K. Vavrova and J. Vinsova, Eur. J. Med. Chem., 46, 4937 (2011);
https://doi.org/10.1016/j.ejmech.2011.07.052.
7. J.D. Bhatt, C.J. Chudasama and K.D. Patel, Bioorg. Med. Chem., 23,
7711 (2015);
https://doi.org/10.1016/j.bmc.2015.11.018.
8. A.T. Mavrova, D. Wesselinova, N. Vassilev and J.A. Tsenov, Eur. J. Med.
Chem., 63, 696 (2013);
https://doi.org/10.1016/j.ejmech.2013.03.010.
9. Y. Jin, Z. Tan, M. He, B. Tian, S. Tiang, I. Hawlett and M.Yang, Bioorg.
Med. Chem., 18, 2135 (2010);
https://doi.org/10.1016/j.bmc.2010.02.003.
10. P. Hernández, M. Cabrera, M.L. Lavaggi, L. Celano, I. Tiscornia, T.
Rodrigues da Costa, L. Thomson, M. Bollati-Fogolín, A.L.P. Miranda,
L.M. Lima, E.J. Barreiro, M. González and H. Cerecetto, Bioorg. Med.
Chem., 20, 2158 (2012);
https://doi.org/10.1016/j.bmc.2012.01.034.
11. S.M. Siddiqui, A. Salahuddin and A. Azam, Eur. J. Med. Chem., 49,
411 (2012);
Fig. 3. Interaction of compound standard with COX-2
https://doi.org/10.1016/j.ejmech.2012.01.030.
12. A.R. Todeschini, A.L.P. de Miranda, K.C.M. da Silva, S.C. Parrini and
E.J. Barreiro, Eur. J. Med. Chem., 33, 189 (1998);
https://doi.org/10.1016/S0223-5234(98)80008-1.
13. F. Haviv, J.D. Ratajczyk, R.W. DeNet, F.A. Kerdesky, R.L. Walters,
S.P. Schmidt, J.H. Holms, P.R. Young and G.W. Carter, J. Med. Chem.,
31, 1719 (1988);
4d, 4j and 4k) for analgesic activity by using acetic acid induced
writhing test. The analgesic data (Table-2) of title compounds
revealed compound (4j) showed prominent activity which is
higher than standard (62 %) followed by compound 4k, 4c
showed moderate activity and remaining all are less active than
standard.
https://doi.org/10.1021/jm00117a010.

2484 Soujanya et al.
Asian J. Chem.
14. G. Rajitha, K.V.S.R.G. Prasad, A. Umamaheswari, D. Pradhan and K.
Bharathi, Med. Chem. Res., 23, 5204 (2014);
17. C.A. Winter, E.A. Risley and G.W. Nuss, Proc. Soc. Exp. Biol. Med.,
111, 544 (1962);
https://doi.org/10.1007/s00044-014-1091-0.
https://doi.org/10.3181/00379727-111-27849.
18. R. Koster, M. Anderson and E.J. De Beer, Federation Proceed., 18,
412 (1959).
19. J.R. Dimmock, S.C. Vashishtha and J.P. Stables, Eur. J. Med. Chem.,
35, 241 (2000);
15. G. Fareed, N. Afza, A. Versiani, N. Fareed, R. Mughal, A. Kalhoro, L.
Iqbal and M. Lateef, J. Serb. Chem. Soc., 78, 1127 (2013);
https://doi.org/10.2298/JSC120917126F.
16. G. Rajitha, N. Saideepa and P. Praneetha, Indian J. Chem., 50B, 729
(2011).
https://doi.org/10.1016/S0223-5234(00)00123-9.