Novel 2-(substituted phenyl Imino)-5-benzylidene-4-thiazolidinones as possible non-ulcerogenic tri-action drug candidates: synthesis, characterization, biological evaluation And docking studies

Article abstract of DOI:10.1007/s00044-018-02288-z

The present research was aimed at the synthesis and screening of 35 novel 2-(substituted phenyl imino)-5-benzylidene-4-thiazolidinones having different substitutions at imino phenyl and arylidene groups. The title compounds were synthesized by Knoevenagel

Full text of DOI:10.1007/s00044-018-02288-z

MEDICINAL
CHEMISTRY
RESEARCH
Medicinal Chemistry Research
https://doi.org/10.1007/s00044-018-02288-z
ORIGINAL RESEARCH
Novel 2-(substituted phenyl Imino)-5-benzylidene-4-thiazolidinones
as possible non-ulcerogenic tri-action drug candidates: synthesis,
characterization, biological evaluation And docking studies
4
Pooja Chawla1 Sourav Kalra2 Raj Kumar2 Ranjit Singh3 Shailendra K. Saraf
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Received: 16 October 2018 / Accepted: 26 December 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract
The present research was aimed at the synthesis and screening of 35 novel 2-(substituted phenyl imino)-5-benzylidene-4-
thiazolidinones having different substitutions at imino phenyl and arylidene groups. The title compounds were synthesized
by Knoevenagel condensation at the 5th position of the 4-thiazolidinone ring, in the presence of sodium acetate. The
structures were assigned on the basis of spectral data. The compounds were screened for in vivo anti-inflammatory,
antinociceptive and in vitro free-radical scavenging activities. The compounds exhibited significant activities when
compared with standard drugs. The distinctive property of the derivatives was that none of them had an acidic group, like
conventional NSAIDs, but exhibited significant in vivo activity in acute inflammation models. Further, the active
compounds of each series were docked against cyclooxygeanase (COX)-2 enzyme using Glide module of Maestro 11.1
program. It was evident from the docking results that 3-chlorophenylimino and 2-chloro moiety on 5-benzylidene nucleus of
the 4-thiazolidinone derivative (30) could easily fit into the COX-2-binding pocket, considered as critical interaction for
COX-2 inhibition. Interestingly, some of the compounds exhibited the potential of becoming dual action or even triple action
drug candidates, which could target degenerative disorders associated with excessive free-radical generation.
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Keywords 4-thiazolidinones Anti-inflammatory Antinociceptive Free-radical scavenging Docking Knoevenagel
condensation
Introduction
2015). In addition to playing a role in direct tissue damage,
their generation may also amplify body’s general inflam-
matory response and promote further cell injury (Clarkson
and Tremblay 1988). The role of free radicals in inflam-
matory process is well known (Flohe et al. 1985). A number
of non-steroidal anti-inflammatory drugs have been reported
to act either as inhibitors of free-radical production or as
radical scavengers (Saldanha et al. 1990). Thus, compounds
with antioxidant properties may offer protection in rheu-
matoid arthritis and inflammation and lead to potentially
An imbalance between cellular production of reactive
oxygen species (ROS) and body’s antioxidant defence
mechanism always leads to oxidative stress. ROS such as
superoxide radical, peroxynitryl, hydroxyl radical, and
hydrogen peroxide are constantly produced as a result of the
metabolic reactions in living systems. Pathogenesis of a
number of diseases has been reported to involve oxygen-
derived free-radicals or ROS (Halliwell and Gutteridge
* Shailendra K. Saraf
Bathinda 151001 Punjab, India
dirpharmniec@gmail.com
3
Adarsh Vijendra Institute of Pharmaceutical Sciences, Shobhit
University, Gangoh, Saharanpur 247341 U.P., India
1
Department of Pharmaceutical Chemistry, Indo-Soviet Friendship
College of Pharmacy (ISFCP), Moga 142001 Punjab, India
4
Babu Banarasi Das Northern India Institute of Technology, Sec-2,
Dr. Akhilesh Das Nagar, Faizabad Road, Lucknow 227105 U.P.,
India
2
Laboratory for Drug Design and Synthesis, Centre for
Pharmaceutical Sciences and Natural Products, School of Basic
and Applied Sciences, Central University of Punjab,

Medicinal Chemistry Research
Scheme 1 Synthetic pathway
for the title compounds
effective drugs. Treatment of various diseases could benefit
from the use of drugs that combine antioxidant and antiin-
flammatory activity. This has already been proved for a
number of commercially available non-steroidal anti-
inflammatory drugs, which simultaneously possess radical
scavenging properties (Orhan and Şahin 2001; Seth et al.
2014).
Experimental section
General
The synthetic route to obtain 2,5-disubstituted 4-
thiazolidinone derivatives (Scheme 1) was through the
chloroacetylation of substituted anilines (1a-e), using
chloroacetyl chloride to form 2-chloro-N-(substituted phe-
nyl) acetamide (2a-e), which upon heterocyclization with
ammonium thiocyanate afforded 2-(substituted phenyl
imino) thiazolidine-4-one (3a-e). Synthesis of 2-(substituted
phenyl imino)-5-substituted arylidene-thiazolidine-4-ones
(1–35) involved Knoevenagel reaction, and these com-
pounds were obtained by condensation of (3a-e) with var-
ious aryl aldehydes in glacial acetic acid in the presence of
sodium acetate (Vicini et al. 2008). The compounds were
characterized using UV, IR, 1HNMR, 13C nuclear magnetic
resonance (NMR), and high-resolution mass spectra
(HRMS) analysis.
Substituted 4-thiazolidinones, in addition to being anti-
inflammatory agents (Taranalli et al. 2008; Bhati and
Kumar 2008) and free-radical scavengers (Shih and Ke
2004), also possess a series of other activities like aldose
reductase inhibitory (Maccari et al. 2011), antidegenerative
(Panico et al. 2011), antimicrobial (Vicini et al. 2006; Omar
et al. 2010), and antihypertensive activity (Bhandari et al.
2009). Substitutions at various positions of this nucleus
have been made and, in particular 2-imino-5-arylidene 4-
thiazolidinones, have been reported to possess anti-
degenerative and antinflammatory activity (Ottana et al.
2005; Ottanà et al. 2007; Singh et al. 2015). 2,5-Dis-
ubstituted 4-thiazolidinones act as lipooxygenase and
cyclooxygeanase (COX) inhibitors (Geronikaki et al. 2008;
Chakraborti et al. 2010), with some authors reporting
selective COX-2 inhibition (Ottana et al. 2005). Some of the
synthesized compounds were evaluated for antimicrobial
activity by our research group and proved to be potent
antimicrobial agents (Chawla et al. 2012a, b). On the basis
of these reports, it was decided to synthesize some 2,5-
disubstituted 4-thiazolidinones and evaluate them for anti-
inflammatory, antinociceptive, and free-radical scavenging
activities.
Starting material, reagents, and solvents were procured
from Aldrich, Himedia, and SD Fine Chemicals and used as
such. Melting points were determined by open capillary
method and are uncorrected. The λmax values were recorded
on a Shimadzu 1700 UV-Visible spectrophotometer. The
infrared (IR) spectra were recorded on a Shimadzu 8400 S
1
FTIR spectrophotometer by KBr pellet technique. HNMR
and 13C NMR spectra were recorded on a Bruker Advance
DRX-300 spectrophotometer, using tetramethyl silane as
the internal standard and DMSO-d6 as the solvent. Chemi-
cal shift (δ) values are reported in ppm. Splitting patterns

Medicinal Chemistry Research
were designated as follows: s (singlet), d (doublet); m
(multiplet). HRMS studies were performed on a JEOL-
Accu TOF JMS-T100LC spectrometer. Progress of the
reactions was monitored on precoated TLC silica gel-G
plates and the spots were detected in an iodine chamber.
CDCl3): 167.5 (CONH, amide), 36.5 (CH2), 150.4 (C═N,
imino), 142.8 2 (C–N), 146.8 (C–NO2 benzene), 126.4–
132.1(4CH, benzene; Mass: M++1 peak at 238.
2-(4-nitrophenylimino) thiazolidin-4-one (3c)
Synthesis of 2-chloro-N-(substituted phenyl) acetamide (2a-
e)
Yellowish orange crystals (17.74 g, 79%); mp 230–233 °C
(dioxane); Rf value: 0.72 (Ethyl acetate: Chloroform 9:1);
IR(KBr, cm−1) ν: 1677 (C═O), 3413 (NH str.), 1510 (NH
bend), 1245 (C–N), 1643 (C═N), 1342 (Ar–NO2 Sym),
1413 (Ar–NO2 Asym), 3260 (C–H arom.), 746 (C–H para
Ice-cold chloroacetyl chloride (52 mL, 0.46 mol) was added
drop-wise to substituted aniline (0.2 mol) (1a-e) with stir-
ring, under anhydrous conditions. The reaction mixture was
stirred at room temperature for 4 h. The semisolid residue
was neutralized with sodium bicarbonate solution. The
contents were filtered off and washed thoroughly with cold
water. The crude mass was air dried and recrystallized from
ethanol.
1
arom.); HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.65 (s,
1H, NH), 4.09 (s, 2H, CH2), 7.54–7.48 (m, 2H, H-2 and 6),
7.95–7.86 (m, 2H, H-3 and 5); 13C NMR (DMSO-d6,
CDCl3): 166.9 (CONH, amide), 36.2 (CH2), 155.8 (C═N,
imino), 150.5 (C–N), 146.9 (C–NO2 benzene),121.5–125.4
(4CH, benzene); Mass: M+1 peak at 238.
Synthesis of 2-(substituted phenyl imino) thiazolidin-4-one
(3a-e)
2-(4-chlorophenylimino) thiazolidin-4-one (3d)
Reaction time 5 h; Rust colored powder (19.94 g, 88%); mp
200–203 °C (dioxane); Rf value: 0.81 (Ethyl acetate:
Chloroform 9:1); IR(KBr, cm−1) ν: 1733 (C═O), 3413(NH
str.), 1598(NH bend), 1257 (C–N); 1637 (C═N) 2921(C–H
arom.), 862 (C–H para arom.); 1150 (Ar–Cl); 1HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 12.08 (s, 1H, NH), 4.01 (s,
2H, CH2), 7.50–7.34 (m, 2H, H-2 and 6), 7.66–7.58 (m, 2H,
H-3 and 5); 13C NMR (DMSO-d6, CDCl3 167.4 (CONH,
amide), 36.4 (CH2), 150.5 (C═N, imino), 145.8 (C–N),
136.9 (C–Cl benzene), 124.2 (2H CH, benzene) 132.4 (2H
CH, benzene); Mass: M+1 peak at 227.
A solution of 2-chloro-N-(substituted phenyl) acetamide
(0.10 mol) and ammonium thiocyanate (15.22 g, 0.20 mol)
was refluxed in ethanol for 5 h and allowed to stand over-
night. The precipitate was filtered, washed with water and
recrystallized from 1,4-dioxane (Omar et al. 2010).
2-(3-chloro-4-fluorophenylimino) thiazolidin-4-one (3a)
Brown powder (14.67 g, 60%); mp 212–215 °C (from
dioxane); Rf value 0.72 (Ethyl acetate: Chloroform 9:1); IR
(KBr) (v cm−1): 1701 (-C═O):, 3400 (-NH- stretch), 1641
(-NH- bend), 1618 (C═N), 1248(C–N), 2922 (C–H stretch
(arom.), 860 (C–H bend (arom. para substituted), 650 and
800 (C–H bend (arom. meta substituted), 1438 (CH2), 1060
2-(3-chlorophenylimino) thiazolidin-4-one (3e)
Dark brown powder (13.59 g, 60%); mp 201–208 °C (from
dioxane); Rf value: 0.74 (Ethyl acetate:Chloroform 9:1); IR
(KBr) (ν cm−1): -C═O: 1701; -NH- stretch 3409; -NH-
bend 1573; -C–N 1247; C═N 1612; C–H stretch (arom.)
3062; CH2: 1446 Ar–Cl 1095; C–H bend meta (arom.) 775,
1
(Ar–Cl), 1191(Ar-F); HNMR (DMSO-d6, 300 MHz) (δ,
ppm): 12.02 (s, 1H, NH), 4.05 (s, 2H, CH2), 8.12 (d, 1H, J
= 25.6 Hz, H-5), 7.45 (s, 1H, H-2), 7.10 (d, 1H, J = 5.5 Hz,
H-6); 13C NMR (DMSO-d6, CDCl3): 167.2 (CONH,
amide), 36.3 (CH2), 159.2 (C═N, imino), 142.2 (C–N),
113.6–116.9 (3CH, benzene), 120.1 (C–Cl, benzene), 150.2
(C–F, benzene); Mass: M+1 peak at 245.5.
1
867; HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.06, (s,
1H, NH), 4.01 (s, 2H, CH2), 7.61 (s, 1H, H-2), 7.65 (d, 1H,
H-4), 7.08-6.99 (m, 1H, H-5), 7.23 (d, 1H, H-6); 13C NMR
(DMSO-d6, CDCl3): 167.8 (CONH, amide), 36.3 (CH2),
150.4 (C═N, imino), 149.8 (C–N),136.2 (C–Cl benzene),
123.4–132.4 (4H CH, benzene); Mass: M+1 peak at 227.
2-(2-nitrophenylimino) thiazolidin-4-one (3b)
Bright orange crystals (17.07 g, 72%); mp 161–164 °C
(dioxane); Rf value: 0.87 (Ethyl acetate: Chloroform 9:1);
IR(KBr, cm−1) ν:1731(C═O), 3463 (NH st), 1593 (NH
bend), 1257 (C–N), 1639 (C═N), 1342 (Ar–NO2 Sym),
1514 (Ar–NO2 Asym), 3001 (C–H arom.), 765 (C–H ortho
arom.); HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.54 (s,
1H, NH), 4.02 (s, 2H, CH2), 7.73–7.56 (m, 2H, H-4 and 5),
7.20 (d, 1H, J = 7.5 Hz, H-6); 13C NMR (DMSO-d6,
Synthesis of 2-(substituted phenyl imino-5-substituted
arylidene 4-thiazolidinones) (1–35)
The 2-(substituted phenyl imino) thiazolidin-4-one (3a-e)
(0.004 mol) was stirred in 35 mL of acetic acid, in the
presence of sodium acetate (0.008 mol). Various aryl alde-
hydes (0.006 mol) were then added and refluxed for
1

Medicinal Chemistry Research
different time periods using standard Knoevenagel reaction
procedure. The progress of the reaction was monitored by
TLC. The reaction mixture was cooled to room temperature
and the precipitated solid was filtered, washed thoroughly
with water and recrystallized from 1,4-dioxane (Omar et al.
2010).
nm; IR (KBr, cm−1) ν: -C═O: 1690; -NH- stretch: 3137;
-NH bend: 1587; -C–N: 1257; C–H stretch (arom.): 3053;
C–H bend (arom. para): 879, 817; (arom. meta): 669, 786;
C═C: 1654; Ar-F: 1257; Ar–Cl: 1100; 1HNMR (DMSO-d6,
300 MHz) (δ, ppm): 12.1 (s, 1H, NH); 8.09 (d, 1H, J = 24,
H-5); 7.74 (s, 1H, CH); 7.66 (d, 2H, J = 8.7, H-3’ and 5’);
7.47 (d, 2H, J = 9.3, H-2’ and 6’); 7.29 (d, 1H, J = 5.0, H-
5); 7.15 (d, 1H, J = 3.9, H-6); 6.962 (s, 1H, H-2); 13C NMR
(DMSO-d6, CDCl3): 168.4 (CONH, amide), 115.8 (C═C,
ethylene), 142.5 (C═C), 163.2 (C═N, imino), 133.1 (1C,
benzene), 133.6 (C–Cl), 128.2–129.5 (4H benzene), 145.3
(C–N), 118.3–122.8 (3H benzene), 124.3 (C–Cl), 158.4 (C–
F); HRMS calcd for C16H9Cl2FN2OS: 365.9797, found
366.9652; Anal. calcd.: C, 53.56; H, 2.91; N, 7.35; found:
C, 53.51; H, 2.87; N, 7.31
2-(3-chloro-4-fluorophenylimino)-5-(benzylidene)-4-
thiazolidinone (1)
Light brown crystals (843 mg, 62%); mp 208–210 °C (from
dioxane); Rf value: 0.69 (Toluene: Ethanol, 8:2); λmax 278
nm; IR(KBr, cm−1) ν: -C═O 1674; -NH- stretch 3419; -NH
bend 1550; -C–N 1244; C═N 1630; stretch (arom.) 3001;
C═C 1633; Ar–Cl 1050, Ar-F 1164; C–H bend (arom.
1
ortho) 758; HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.3
(s, 1H, NH), 8.09 (d, 1H, J = 29.4 Hz, H-5), 7.85 (s, 1H,
CH), 7.65 (d,2H, J = 12.3 Hz, H-3’and 5’), 7.29 (d, 1H, J =
5.1 Hz, H-4’), 7.15 (s, 1H, H-2), 7.07 (d, 2H, J = 3.1 Hz, H-
2’and 6’); 13C NMR (DMSO-d6, CDCl3): 168.4 (CONH,
amide), 115.9 (C═C, ethylene), 145.2 (C═C),163.5 (C═N,
imino), 126.6–129.5 (5CH, benzene), 133.6 (1C, benzene),
147.2 (C–N), 120.3–125.8 (3CH, benzene), 126.5 (C–Cl),
159.8 (C–F); HRMS calcd for C16H10ClFN2OS: 332.0186,
found 333.0165; Anal.Calcd.: C, 58.87; H, 3.49; N, 8.08;
Found: C, 58.77; H, 3.42; N, 8.01.
2-(3-chloro-4-fluorophenylimino)-5-(4-
hydroxybenzylidene)-4-thiazolidinone (4)
Yellowish white crystals (981 mg, 69%); mp 210–213 °C
(from dioxane); Rf value: 0.73 (Toluene: Ethanol, 8:2); λmax
267 nm; IR (KBr, cm−1) ν: -C═O: 1703; -NH- stretch:
3406; - NH- bend: 1585; -C–N: 1259; C–H stretch (arom.):
3055; C–H bend (arom. para): 819, 883; (arom. meta): 653,
744; Ar-F: 1191; C═C: 1643; Ar–Cl: 1056; Ar-OH: 3500;
1
C–O: 1220; HNMR (DMSO-d6, 300 MHz) (δ, ppm): 11.8
(s, 1H, NH); 8.0 (s, 1H, CH); 7.15 (d, 2H, J = 4.5, H-3’ and
5’); 6.95 (d, 2H, J = 3.6, H-2’ and 6’); 7.70 (m, 3H, H-2, 5
and 6); 13C NMR (DMSO-d6, CDCl3): 168.6 (CONH,
amide), 115.6 (C═C, ethylene), 163.4 (C═N, imino), 142.5
(C═C), 116.8 (2H benzene), 131.2 (2H benzene), 128.8 (1C
benzene), 158.7 (C–OH), 145.3 (C–N), 118.8–122.7 (3H
benzene), 124.3 (C–Cl), 157.4 (C–F); HRMS calcd for
C16H10ClFN2O2S: 348.0136, found 349.0015; Anal. calcd.:
C, 56.28; H, 3.33; N, 7.72; found: C, 56.21; H, 3.29; N,
7.75.
2-(3-chloro-4-fluorophenylimino)-5-(2-chlorobenzylidene)-
4-thiazolidinone (2)
Off-white crystals (1.0 g, 67%); mp 195–200 °C (from
dioxane); Rf value: 0.69 (Toluene: Ethanol, 8:2); λmax 274
nm; IR(KBr, cm−1) ν: C═O: 1703; -NH- stretch: 3253; -NH
bend: 1587; C═N: 1616; -C–N: 1242; C–H stretch (arom.):
3053; C–H bend (arom. meta): 648, 759; C–H bend (arom.
para): 819; C–H bend (arom. ortho): 750; C═C: 1643; Ar–
1
Cl: 1100; Ar-F: 1242; HNMR (DMSO-d6, 300 MHz) (δ,
ppm): 11.358 (s, 1H, NH); 8.31 (d, 1H, J = 14.1, H-5; 7.8 (s,
1H, CH); 7.269 (t, 1H, J = 2.1, H-4’); 7.156 (d, 1H, J = 4.8,
H-6’); 7.04 (m, 2H, J = 5.4, H-3’ and 5’); 6.962 (s, 1H, H-
2); 13C NMR (DMSO-d6, CDCl3): 168.5 (CONH, amide),
115.7 (C═C, ethylene), 142.9 (C═C), 163.6 (C═N, imino),
132.8 (1C,benzene), 135.2 (C–Cl), 126.1–129.8 (4CH,
benzene),146.3 (C–N), 118.6–122.8 (3H benzene), 124.8
(C–Cl), 158.9 (C–F); HRMS calcd for: C16H9Cl2FN2OS:
365.9797, found 366.9628; Anal.calcd.: C, 53.56; H, 2.91;
N, 7.35; found: C, 53.45; H, 2.89; N, 7.38.
2-(3-chloro-4-fluorophenylimino)-5-(2-nitrobenzylidene)-4-
thiazolidinone (5)
Reaction time 5 h; Rust colored crystals (976 mg, 63%); mp
189–191 °C (from dioxane); Rf value: 0.66 (Toluene:
Ethanol 8:2); λmax 267 nm; IR (KBr, cm−1) ν: -C═O: 1703;
-NH- stretch: 3436; - NH- bend: 1585; C═N: 1614; -C–N:
1259; C–H stretch (aromatic): 3053; C–H bend (arom.
ortho): 750; C–H bend (arom. meta): 651, 786; C–H bend
(arom. para): 819; C═C: 1643, Ar–NO2: 1346(sym), 1504
(asym); Ar–Cl: 1056; Ar-F: 1191; 1HNMR (DMSO-d6, 300
MHz) (δ, ppm): 11.9 (s, 1H, NH); 8.268 (s, 1H, CH); 8.234
(d, 1H, J = 4.2, H-5); 7.249 (d, 1H, J = 6.6, H-3’); 6.98 (m,
2H, J = 4.8, H-4’ and 5’); 7.149 (s, 1H, H-2); 8.18 (d, 1H, J
= 5.1, H-6’); 8.05 (d, 1H, J = 3.9, H-6); 13C NMR (DMSO-
d6, CDCl3): 168.4 (CONH, amide), 115.9 (C═C, ethylene),
2-(3-chloro-4-fluorophenylimino)-5-(4-chlorobenzylidene)-
4-thiazolidinone (3)
Light brown crystals (957 mg, 64%); mp 215–220 °C (from
dioxane); Rf value: 0.71 (Toluene: Ethanol, 8:2); λmax 347

Medicinal Chemistry Research
163.4 (C═N, imino), 142.6 (C═C), 127.8 (2C benzene),
123.4 (1C benzene), 127.9 (1C benzene), 135.23 (1C ben-
zene), 148.2 (C–NO2), 146.2 (C–N), 118.8–122.7 (3C
benzene), 124.3 (C–Cl), 157.4 (C–F); HRMS calcd for
C16H9ClFN3O3S: 377.7774, Found 377.9906; Anal. calcd.:
C, 52.11; H, 2.83; N, 10.72; found: C, 52.13; H, 2.80; N,
10.74.
2-(2-nitrophenylimino)-5-benzylidene-4-thiazolidinone (8)
Light brown powder (945 mg, 69%); mp 238–240 °C
(dioxane); Rf value: 0.69 (Toluene: Ethanol, 8:2); λmax: 285
nm; IR(KBr, cm−1) ν: 1726 (C═O), 3423 (NH str.), 1593
(NH bend), 1251(C–N), 1643 (C═N), 3009 (C–H str.
arom.), 1633(C═C), 1344 (Ar–NO2 Sym), 1519 (Ar–NO2
1
Asym); 761, 326 (C–H arom. ortho); HNMR (DMSO-d6,
2-(3-chloro-4-fluorophenylimino)-5-(3-nitrobenzylidene)-4-
thiazolidinone (6)
300 MHz) (δ, ppm): 12.74 (s, 1H, NH), 8.04 (d, 1H, J = 8.1
Hz, H-3), 7.51(s, 1H, CH), 7.73–7.64 (m, 2H, H-4 and 5),
7.30 (d, 1H, J = 7.5 Hz, H-6), 7.30–7.18 (m, 2H, H-2’ and
6’), 7.44–7.31 (m, 2H, H-3’ and 5’), 7.39 (m, 1H, J = 7.2
Hz, H-4’); 13C NMR (DMSO-d6, CDCl3): 168.8 (CONH,
amide), 116.6 (C═C, ethylene), 163.2 (C═N, imino), 142.6
(C═C), 136.5 (1C benzene), 127.7–129.2 (5C benzene),
142.3 (C–N), 145.9 (C–NO2), 125.5 (1C benzene), 128.6–
131.3 (3C benzene); HRMS calcd for C16H11N3O3S:
325.3418, found 326.0326; Anal. calcd.: C, 60.17; H, 3.86;
N, 12.38; found: C, 60.14; H, 3.85; N, 12.39.
Light brown crystals (1.0 g, 63%); mp 240–245 °C (from
dioxane); Rf value: 0.72 (Toluene: Ethanol, 8:2); λmax 339
nm; IR (KBr, cm−1) ν: -C═O: 1681; -NH- stretch: 3421;
-NH- bend: 1637; C═N: 1600; -C–N: 1263; C═C: 1637; C–
H stretch (arom.): 3045; C–H bend (arom. meta): 669, 750;
C–H bend (arom. para): 819; Ar–NO2: 1350 (sym), 1498
(asym); Ar–Cl: 1056; Ar-F: 1184; 1HNMR (DMSO-d6, 300
MHz) (δ, ppm): 12.4 (s, 1H, NH); 8.39 (d, 1H, J = 11.4, H-
5); 8.24(d, 1H, J = 3.3, H-5’); 8.06 (d, 1H, J = 8.1, H-4’);
7.822 (d, 1H, J = 7.8, H-6); 7.822 (m, 2H, J = 14.7, H-2’
and 6’); 7.575 (s, 1H, CH); 13C NMR (DMSO-d6, CDCl3):
168.1 (CONH, amide), 116.2 (C═C, ethylene), 163.2
(C═N, imino), 142.1 (C═C), 122.7–123.1 (2C benzene),
130.2 (1C benzene), 136.5 (1C benzene), 135.8 (1C ben-
zene), 147.4 (C–NO2), 146.1 (C–N), 118.5–122.4 (3C
benzene), 124.3 (C–Cl), 157.1 (C–F); HRMS calcd for
C16H9ClFN3O3S: 377.7774, found 378.0016; Anal. calcd.:
C, 52.11; H, 2.83; N, 10.72; found: C, 52.14; H, 2.81; N,
10.70.
2-(2-nitrophenylimino)-5-(2-chlorobenzylidene)-4-
thiazolidinone (9)
Rust powder (986 mg, 65%); mp 242–247 °C (dioxane); Rf
value: 0.69 (Toluene: Ethanol, 8:2); λmax: 331 nm; IR (KBr,
cm−1) ν: 1720 (C═O); 3423 (NH str.), 1562 (NH bend),
1658(C═N), 1253(C–N), 1643(C═C), 1342 (Ar–NO2
Sym), 1517 (Ar–NO2 Asym); 1041 (Ar–Cl), 761, 779 (C–H
arom. ortho); 1HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.9
(s, 1H, NH), 8.04 (d, 1H, J = 8.1 Hz, H-3), 7.85 (s, 1H,
CH), 7.72–7.60 (m, 2H, H-4 and 5), 7.97 (d, 1H, J = 7.8 Hz,
H-6), 7.28 (d, 1H, J = 7.8 Hz, H-3’), 7.61–7.46 (m, 2H, H-
4’ and 5’), 7.17 (d, 1H, J = 7.5 Hz, H-6’); 13C NMR
(DMSO-d6, CDCl3): 168.5 (CONH, amide), 116.4 (C═C,
ethylene), 163.3 (C═N, imino), 142.5 (C═C), 133.5 (1C
benzene), 126.3–129.7 (4C benzene), 134.2 (C–Cl), 142.4
(C–N), 145.9 (C–NO2), 125.6–131.5 (4C benzene); HRMS
calcd for C16H10ClN3O3S: 359.7869, found 360.2831; Anal.
calcd.: C, 54.62; H, 3.24; N, 11.24; found: C, 54.64; H,
3.22; N, 11.22.
2-(3-chloro-4-fluorophenylimino)-5-(4-hydroxy-3-
methoxybenzylidene)-4-thiazolidinone (7)
Mustard colored crystals (898 mg, 58%); mp 198–201 °C
(from dioxane); Rf value: 0.77 (Toluene: Ethanol, 8:2); λmax
267 nm; IR (KBr, cm−1) ν: -C═O 1728, -NH- stretch 3251,
-NH bend 1614, C═N 1585, -C–N 1259, C═C 1650; C–H
stretch (arom.) 3040; Ar-OH 3452 (Broad band); C–H bend
(arom. ortho) 765; C–H bend (arom. meta) 821 and 871, C–
1
H bend (arom. para) 805; HNMR (DMSO-d6, 300 MHz)
(δ, ppm): 12.91 (s, 1H, NH), 7.78 (s, 1H, H- 2), 7.40-6.91
(m, 2H, H- 5 and 6), 7.781 (s, 1H, CH), 7.67 (s, H-2’), 7.58
(m, 2H, H = 5’ and 6’), 10.20 (s, OH); 13C NMR (DMSO-
d6, CDCl3): 168.3 (CONH, amide), 116.4 (C═C, ethylene),
142.2 (C═C), 163.2 (C═N, imino), 111.2–116.9 (2C ben-
zene), 130.1 (1C benzene), 123.5 (1C benzene), 147.5 (C–
OH), 149.9 (1C benzene), 56.6 (OCH3), 146.3 (C–N),
119.8- 122.6 (3C benzene), 124.5 (C–Cl), 158.1 (C–F);
HRMS calcd for C17H12ClFN2O3S: 378.0241, found
380.9928; Anal. calcd.: C, 55.03; H, 3.59; N, 7.13; found:
C, 55.06; H, 3.62; N, 7.10.
2-(2-nitrophenylimino)–5-(4-chlorobenzylidene)-4-
thiazolidinone (10)
Buff colored powder (1.04 g, 69%); mp 205–210 °C
(dioxane); Rf value: 0.85 (Toluene: Ethanol, 8:2); λmax: 285
nm; IR (KBr, cm−1) ν: 1722 (C═O); 3450 (NH str.); 1255
(C–N); 2997 (C–H arom.), 1643 (C═C), 1344 (Ar–NO2
Sym), 1519 (Ar–NO2 Asym); 1057 (Ar–Cl), 757(C–H
1
ortho), 800 (C–H arom. para); HNMR (DMSO-d6, 300
MHz) (δ, ppm): 12.79 (s, 1H, NH), 8.04 (d, 1H, J = 8.1 Hz,
H-3), 7.54 (s, 1H, CH), 7.97–7.67 (m, 2H, J = 7.5 Hz, H-4

Medicinal Chemistry Research
and 5), 7.97 (d, 1H, J = 8.1 Hz, H-6), 7.40–7.38 (m, 2H, H-
2’and 6’), 7.35–7.16 (m, 2H, H-3’ and 4’); 13C NMR
(DMSO-d6, CDCl3): 168.6 (CONH, amide), 116.1 (C═C,
ethylene), 163.4 (C═N, imino), 142.3 (C═C), 128.4–129.4
(4C benzene), 133.6 (1C benzene), 133.9 (C–Cl), 142.6 (V-
N), 126.5–131.4 (4C benzene), 145.5 (C–NO2); HRMS
calcd for C16H10ClN3O3S: 359.7869, found 360.0325; Anal.
calcd.: C, 54.62; H, 3.24; N, 11.24; found: C, 54.64; H,
3.26; N, 11.27.
2-(2-nitrophenylimino)-5-(3-nitrobenzylidene)-4-
thiazolidinone (13)
Reaction time: 9 h; Light orange powder (982 mg, 63%);
mp 230–235 °C (dioxane); Rf value: 0.71 (Toluene: Etha-
nol, 8:2); λmax: 284 nm; IR (KBr, cm−1) ν: 1726(C═O),
3452 (NH str.), 1253 (C–N), 1600(C═N), 3060 (C–H
arom.), 1665(C═C), 1350 (Ar–NO2 Sym), 1519 (Ar–NO2
Asym), 745(C–H ortho), 795, 821 (C–H arom. meta);
1HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.91 (s, 1H,
NH), 8.24 (d, 1H, J = 7.8 Hz, H-3), 7.78–7.73 (m, 2H, H-4
and 5), 8.05 (d, 1H, J = 7.5 Hz, H-6), 7.88 (s, 1H, CH); 8.39
(s, 1H, H-2’), 7.93 (d, 1H, J = 7.5 Hz, H-4’), 7.42 (t, 1H, J
= 7.8 Hz, H-5’), 7.32 (d, 1H, J = 7.5 Hz, H-6’); 13C NMR
(DMSO-d6, CDCl3): 168.2 (CONH, amide), 116.6 (C═C,
ethylene), 163.2 (C═N, imino), 142.6 (C═C), 136.5 (1C
benzene), 134.2 (1C benzene), 122.9–123.9 (2C benzene),
134.9 (1C benzene), 147.4 (C–NO2), 142.3 (C–N), 145.5
(C–NO2), 125.3 (1C benzene), 128.2–131.2 (3C benzene);
HRMS calcd for C16H10N4O5S: 370.3394, found 371.2654;
Anal. calcd.: C, 53.12; H, 3.15; N, 14.58; found: C, 53.15;
H, 3.13; N, 14.56.
2-(2-nitrophenylimino)-5-(4-hydroxybenzylidene)-4-
thiazolidinone (11)
Reaction time: 8.5 h; Brown powder (1.04 g, 72%); mp
210–215 °C (dioxane); Rf value: 0.67 (Toluene: Ethanol,
8:2); λmax: 280 nm; IR (KBr, cm−1) ν: 1703(C═O), 3338
(NH str.), 1276(C–N), 1600(C═N), 3026(C–H arom.), 1656
(C═C), 1342 (Ar–NO2 Sym), 1514 (Ar–NO2 Asym), 3326
(Ar-OH Broad), 765(C–H arom. ortho), 805 (C–H para);
1HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.34 (s, 1H,
NH), 8.01 (d, 1H, H-3), 7.59 (s, 1H, CH), 7.81–7.67 (m,
3H, H-4, 5, 6), 7.37–7.19 (m, 2H, H-2’ and 6’), 7.17-6.85
(m, 2H, H-3’ and 5’), 10.18 (s, OH); 13C NMR (DMSO-d6,
CDCl3): 168.3 (CONH, amide), 116.5 (C═C, ethylene),
163.1 (C═N, imino), 142.4 (C═C), 127.4 (1C benzene),
130.4 (2C benzene), 116.1 (2C benzene), 158.2 (C–OH),
142.3 (C–N), 145.1 (C–NO2), 125.3–128.2 (2C benzene),
130.2–131.2 (2C benzene); HRMS calcd for C16H11N3O4S:
341.3412, found 342.0561; Anal. calcd.: C, 57.46; H, 3.69;
N, 11.82; found: C, 57.43; H, 3.67; N, 11.84.
2-(2-nitrophenylimino)-5-(4-hydroxy-3-
methoxybenzylidene)-4-thiazolidinone (14)
Reaction time: 10 h; Mustard powder (985 mg, 63%); mp
245–250 °C (dioxane); Rf value: 0.73 (Toluene: Ethanol,
8:2); λmax: 283 nm; IR (KBr, cm−1) ν: 1726 (C═O), 3452
(NH str.), 1253(C–N), 1600(C═N), 3060 (C–H arom.),
1665 (C═C), 1342 (Ar–NO2 Sym), 1514 (Ar–NO2 Asym),
3452 (Ar-OH Broad band); 765 (C–H arom. ortho); 821,
2-(2-nitrophenylimino)-5-(2-nitrobenzylidene)-4-
thiazolidinone (12)
1
871 (C–H arom. meta), 805 (C–H arom. para); HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 12.12 (s, 1H, NH), 7.83 (d,
1H, J = 3.9 Hz, H-3), 8.30–8.01(m, 3H, H-4, 5, and 6), 7.25
(s, 1H, CH), 6.93 (s, 1H, H-2), 7.43–7.39 (m, 2H, H-5’ and
6’), 9.85 (s, OH), 4.009 (s, 3H, OCH3); 13C NMR (DMSO-
d6, CDCl3): 168.4 (CONH, amide), 116.4 (C═C, ethylene),
163.5 (C═N, imino), 142.4 (C═C), 128.5 (1C benzene),
111.7 (1C benzene), 116.9 (1C benzene), 122.2 (1C ben-
zene), 147.6 (C–OH), 149.4 (1C benzene), 56.4 (CH3),
142.4 (C–N), 145.3 (C–NO2), 125.7 (1C benzene), 128.6
(1C benzene), 131.3 (1C benzene), 130.5 (1C benzene);
HRMS calcd for C17H13N3O5S: 371.3672, found 372.1055;
Anal. calcd.: C, 56.10; H, 3.92; N, 10.90; found: C, 56.13;
H, 3.90; N, 10.93.
Light brown powder (936 mg, 60%); mp 230–235 °C
(dioxane); Rf value: 0.81(Toluene: Ethanol 8:2); λmax: 284
nm; IR (KBr, cm−1) ν: 1726 (C═O), 3415(NH str.), 1257
(C–N), 1600(C═N), 3001 (C–H arom.), 1643(C═C), 1342
(Ar–NO2 Sym), 1514 (Ar–NO2 Asym), 763, 801 (C–H
arom. ortho); 1HNMR (DMSO-d6, 300 MHz) (δ, ppm):
12.88 (s, 1H, NH), 8.16 (d, 1H, J 8.1 Hz H-3), 8.15–7.95
(m, 2H, H-4 and 5), 8.01 (d, 1H, J = 8.1 Hz, H-6), 7.92 (s,
1H, CH), 7.25 (d, 1H, J = 7.8 Hz, H-3’), 7.71–7.61 (m, 2H,
H-4’ and 5’), 7.79 (d, 1H, J = 7.5 Hz, H-6’); 13C NMR
(DMSO-d6, CDCl3): 168.6 (CONH, amide), 116.2 (C═C,
ethylene), 163.4 (C═N, imino), 142.3 (C═C), 127.5 (2C
benzene), 123.4 (1C benzene), 128.9 (1C benzene), 134.9
(1C benzene), 147.9 (C–NO2), 142.8 (C–N), 147.3 (C–
NO2), 126.3–131.2 (4C benzene); HRMS calcd for
C16H10N4O5S: 370.3394, found 371.0268; Anal. calcd.: C,
53.12; H, 3.15; N, 14.58; found: C, 53.14; H, 3.11; N,
14.56.
2-(4-nitrophenylimino)-5-benzylidene-4-thiazolidinone (15)
Light brown (986 mg, 72%); mp 280–283 °C (dioxane); Rf
value: 0.72 (Toluene: Ethanol, 8:2); λmax: 285 nm; IR(KBr,
cm−1) ν: 1665 (C═O), 3269(NH str.), 1565(NH bend), 1244

Medicinal Chemistry Research
(C–N), 1631(C═N), 3016 (C–H arom.), 1631 (C═C), 1342
(Ar–NO2 Sym), 1519 (Ar–NO2 Asym), 748 (C–H arom.
para); HNMR (DMSO-d6, 300 MHz): (δ, ppm): 12.74 (s,
(C═C, ethylene), 163.2 (C═N, imino), 142.5 (C═C), 133.6
(1C benzene), 129.3 (2C benzene), 128.4 (2C benzene),
133.9 (C–Cl), 155.5 (C–N), 123.3 (2C benzene), 125.3 (2C
1
1H, NH), 7.40 (d, 1H, J = 8.1 Hz, H-2), 7.95 (d, 1H, J =
6.9 Hz, H-3), 7.45–7.40 (m, 2H, H-5 and 6), 7.51 (s, 1H,
CH), 7.18–7.15 (m, 2H, H-2’ and 6’), 7.76–7.71 (m, 3H, H-
4’, 3’ and 5’); 13C NMR (DMSO-d6, CDCl3): 168.6
(CONH, amide), 116.4 (C═C, ethylene),163.3 (C═N,
imino), 142.4 (C═C), 135.5 (1C benzene), 128.9 (2C ben-
zene), 127.4–128.9 (3C benzene), 154.3 (C–N), 146.2 (C–
NO2), 123.6 (2C benzene), 125.3 (2C benzene); HRMS
calcd for C16H11N3O3S: 325.3418, found 326.0695; Anal.
calcd.: C, 60.83; H, 4.82; N, 11.82; found: C, 60.85; H,
4.80; N, 11.85.
benzene),
146.5
(C–NO2);
HRMS
calcd
for
C16H10ClN3O3S: 359.7869, found 360.0356; Anal. calcd.:
C, 54.62; H, 3.24; N, 11.24; found: C, 54.64; H, 3.22; N,
11.21.
2-(4-nitrophenylimino)–5-(4-hydroxybenzylidene)-4-
thiazolidinone (18)
Reaction time: 8 h; Light yellow powder (1.03 g, 72%); mp
> 320 °C (dioxane); Rf value: 0.70 (Toluene: Ethanol, 8:2);
λ
max: 254 nm; IR (KBr, cm−1) ν: 1665(C═O), 3272 (NH
str.), 1244(C–N), 1565 (C═N), 3014 (C–H arom.), 1631
(C═C), 1340 (Ar–NO2 Sym), 1517 (Ar–NO2 Asym), 3413
(Ar-OH Broad band), 794, 856 (C–H arom. para); HNMR
2-(4-nitrophenylimino)-5-(2-chlorobenzylidene)-4-
thiazolidinone (16)
1
(DMSO-d6, 300 MHz) (δ, ppm): 12.34 (s, 1H, NH), 7.38 (s,
1H, H-2), 8.03–7.77 (m, 3H, H-3,5,6), 7.60(s, 1H, CH),
7.38–7.17 (m, 2H, H-2’ and 6’), 7.71–7.59 (m, 2H, H-3’
and 5’), 10.18 (s, OH); 13C NMR (DMSO-d6, CDCl3):
168.3 (CONH, amide), 116.1 (C═C, ethylene), 163.2
(C═N, imino), 142.4 (C═C), 127.5 (1C benzene), 130.9
(2C benzene), 116.1, 116.1 (2C benzene), 157.2 (C–OH),
155.3 (C–N), 123.5 (2C benzene), 125.4 (2C benzene),
146.6 (C–NO2); HRMS calcd for C16H11N3O4S: 341.3412,
found 342.0532; Anal. calcd.: C, 57.46; H, 3.69; N, 11.82;
found: C, 57.44; H, 3.67; N, 11.80.
Reaction time: 7 h; Rust powder (986 mg, 65%); mp 250–
255 °C (dioxane); Rf value: 0.69 (Toluene: Ethanol, 8:2);
λ
max: 255 nm; IR (KBr, cm−1) ν: 1665(C═O), 3270(NH
str.), 1244(C–N), 1631(C═N), 3014 (C–H arom.), 1631
(C═C), 1342 (Ar–NO2 Sym), 1517 (Ar–NO2 Asym), 1114
(Ar–Cl), 748 (C–H arom. ortho), 794 (C–H arom. para);
1HNMR (DMSO-d6, 300 MHz) (δ, ppm): 12.90, (s, 1H,
NH), 7.46, (s, 1H, H-2), 8.04 (d, 1H, J = 8.1 Hz, H-3),
7.72–7.96 (m, 2H, H-5 and 6), 7.86(s, 1H, CH), 7.71–7.29
(d, 2H, H-3’ and 6’), 7.43 (t, 2H, J = 9.6 Hz, H-4’ and 5’);
13C NMR (DMSO-d6, CDCl3): 168.4 (CONH, amide),
116.3 (C═C, ethylene), 163.4 (C═N, imino), 142.1 (C═C),
133.5 (1C benzene), 134.9 (C–Cl), 129.1–129.7 (2C ben-
zene), 126.6 (1C benzene), 127.2 (1C benzene), 154.9 (C–
N), 123.5 (2C benzene), 125.6 (2C benzene), 146.8 (C–
NO2); HRMS calcd for C16H10ClN3O3S: 359.7869, found
360.5326; Anal. calcd.: C, 54.62; H, 3.24; N, 11.24; found:
C, 54.64; H, 3.20; N, 11.22.
2-(4-nitrophenylimino)-5-(2-nitrobenzylidene)-4-
thiazolidinone (19)
Reaction time: 9 h; Light brown (936 mg, 60%); mp 250–
252 °C (dioxane); Rf value: 0.76 (Toluene: Ethanol, 8:2);
λ
max: 255 nm; IR (KBr, cm−1) ν: 1677 (C═O); 3278(NH-
str.), 1244 (C–N), 1599 (C═N), 2983 (C–H arom.), 1643
(C═C), 1385(Ar–NO2 Sym), 1510 (Ar–NO2 Asym), 745
(C–H arom. ortho), 800 (C–H para); HNMR (DMSO-d6,
1
2-(4-nitrophenylimino)-5-(4-chlorobenzylidene)-4-
thiazolidinone (17)
300 MHz) (δ, ppm): 12.88 (s,1H, NH), 7.96 (s, 1H, H-2),
8.16 (d, 1H, J = 8.1 Hz, H-3), 7.80 (t, 1H, J = 7.2 Hz, H-5),
7.26 (d, 1H, J = 7.8 Hz, H-6), 7.92 (s, 1H, CH), 8.01 (d, 1H,
J = 8.01 Hz, H-3’), 7.80 (t, 1H, J = 7.2 Hz, H-4’), 7.69 (t,
1H, J = 7.8 Hz, H-5’), 7.26 (d, 1H, J = 7.8 Hz, H-6’); 13C
NMR (DMSO-d6, CDCl3): 168.1 (CONH, amide), 116.4
(C═C, ethylene), 163.1 (C═N, imino), 142.6 (C═C), 127.5
(2C benzene), 123.7 (1C benzene), 128.1 (1C benzene),
134.6 (1C benzene), 147.9 (C–NO2), 155.4 (C–N), 123.3
(2C benzene),, 125.4 (2C benzene), 146.6 (C–NO2); HRMS
calcd for C16H10N4O5S: 370.3394, found 371.0649; Anal.
calcd.: C, 53.12; H, 3.15; N, 14.58; found: C, 53.14; H,
3.13; N, 14.60.
Reaction time: 8 h; Light yellow (1.05 g, 69%); mp 245–
250 °C (dioxane); Rf value: 0.85 (Toluene: Ethanol, 8:2);
λ
max: 254 nm; IR (KBr, cm−1) ν: 1665(C═O), 3274(NH
str.), 1244 (C–N), 1565 (C═N), 3018(C–H arom.), 1643
(C═C), 1344 (Ar–NO2 Sym), 1517 (Ar–NO2 Asym), 1114
(Ar–Cl); 817, 854 (C–H arom. para); HNMR (DMSO-d6,
1
300 MHz) (δ, ppm): 12.79 (s, 1H, NH), 7.71 (s, 1H, H-2),
8.04 (d, 1H, J = 8.1 Hz, H-3), 7.40 (t, 1H, J = 7.5 Hz, H-5),
7.30 (d, 1H, J = 7.8 Hz, H-6), 7.54 (s, 1H, CH), 7.31–7.16
(m, 2H, H-2’ and 6’), 7.96–7.71 (d, 2H, H-3’ and 5’); 13C
NMR (DMSO-d6, CDCl3): 168.3 (CONH, amide), 116.1

Medicinal Chemistry Research
2-(4-nitrophenylimino)-5-(3-nitrobenzylidene)-4-
thiazolidinone (20)
1245 (C–N), 1564 (C═N), 2963 (C–H arom.), 1639 (C═C),
1087 (Ar–Cl), 761 (C–H arom. para); HNMR (DMSO-d6,
1
300 MHz) (δ, ppm): 11.31 (s, 1H, NH), 7.06–7.51 (m, 4H,
H-2,3,5,6), 6.57 (s, 1H, CH), 7.57–7.65 (m, 2H, H-2’,6’),
7.65–8.01 (m, 3H, H = 3’,4’,5’); 13C NMR (DMSO-d6,
CDCl3): 168.6 (CONH, amide), 116.3 (C═C, ethylene),
165.2 (C═N, imino), 142.5 (C═C), 136.8 (1C benzene),
128.8 (2C benzene), 128.7 (2C benzene), 127.1 (1C ben-
zene), 147.8 (C–N), 122.6 (2C benzene), 130.3 (1C ben-
zene), 132.3 (C–Cl); HRMS calcd for C16H11ClN2OS:
314.7893, found 315.0595; Anal. calcd.: C, 62.69; H, 4.97;
N, 8.12; found: C, 62.67; H, 4.98; N, 8.14.
Reaction time: 9 h; Light brown (982 mg, 63%); mp > 310 °
C (dioxane); Rf value: 0.80 (Toluene: Ethanol, 8:2); λmax
:
255 nm; IR (KBr, cm−1) ν: 1677 (C═O); 3278 (NH str.),
1242 (C–N), 1596 (C═N), 2945 (C–H arom.), 1643(C═C),
1344 (Ar–NO2 Sym), 1514 (Ar–NO2 Asym), 748 (C–H
arom. para), 808, 845 (C–H arom. meta); 1HNMR (DMSO-
d6, 300 MHz) (δ, ppm): 12.91 (s, 1H, NH), 8.39 (s, 1H, H-
2), 8.24 (d, 1H, J = 7.8 Hz, H-3), 7.75 (t, 1H, J = 6.6 Hz, H-
5), 7.32 (d, 1H, J = 7.5 Hz, H-6), 7.88 (s, 1H, CH), 8.39 (s,
1H, H-2’), 8.05 (d, 1H, J = 7.5 Hz, H-4’), 7.42 (t, 1H, J =
7.8 Hz, H-5’), 7.93 (d, 1H, J = 7.5 Hz, H-6’); 13C NMR
(DMSO-d6, CDCl3): 168.7 (CONH, amide), 116.1 (C═C,
ethylene), 163.6 (C═N, imino), 142.5 (C═C), 136.5 (1C
benzene), 122.9 (1C benzene), 123.4 (1C benzene),, 129.6
(1C benzene), 134.2 (1C benzene), 147.7 (C–NO2), 155.4
(C–N), 123.3 (2C benzene),, 125.1 (2C benzene),, 146.6
(C–NO2); HRMS calcd for C16H10N4O5S: 370.3394, found
371.3654; Anal. calcd.: C, 53.12; H, 3.15; N, 14.58; found:
C, 53.10; H, 3.12; N, 14.57.
2-(4-chlorophenylimino)-5-(2-chlorobenzylidene)-4-
thiazolidinone (23)
Off-white powder (1.10 g, 72%); mp 310–312 °C (dioxane),
Rf value: 0.69 (Toluene: Ethanol 8:2), λmax: 276 nm, IR
(KBr, cm−1) ν: 1724 (C═O), 3413 (NH str.), 1490 (NH
bend), 1245 (C–N), 1606 (C═N), 2908 (C–H arom.), 1649
(C═C), 1091 (Ar–Cl), 756 (C–H arom. ortho), 825 (C–H
arom. para); 1HNMR(DMSO-d6, 300 MHz) (δ, ppm):
11.784 (s, 1H, NH), 7.628–7.593 (m, 2H, H-2 & 6), 6.98–
7.07 (m, 2H, H-3,5), 7.92 (s, 1H, CH), 7.57 (d, 1H, J = 9.3
H-3’), 7.44–7.60 (m, 2H, H = 4’,5’), 7.546 (d, 1H, J = 9.3,
H-6’); 13C NMR (DMSO-d6, CDCl3): 168.2 (CONH,
amide), 116.1 (C═C, ethylene), 163.5 (C═N), 142.2 (C═C),
133.4 (1C benzene), 134.4 (1C benzene), 129.8 (1C ben-
zene), 129.1 (1C benzene), 126.7 (1C benzene), 127.9 1C
benzene), 147.4 (C–N), 122.4 (2C benzene), 130.7 (2C
benzene), 132.8 (C–Cl); HRMS calcd for C16H10Cl2N2OS:
349.2344, found 349.0219; Anal. calcd.: C, 56.21; H, 3.33;
N, 7.71; found: C, 56.23; H, 3.31; N, 7.73.
2-(4-nitrophenylimino)-5-(4-hydroxy-3-
methoxybenzylidene)-4-thiazolidinone (21)
Mustard powder (985 mg, 63%); mp 270–275 °C (dioxane);
Rf value: 0.78 (Toluene: Ethanol, 8:2); λmax: 254 nm; IR
(KBr, cm−1) ν: 1665 (C═O), 3271 (NH str.), 1244 (C–N),
1565 (C═N), 3016 (C–H arom.), 1631 (C═C), 1340 (Ar–
NO2 Sym), 1517 (Ar–NO2 Asym), 3423 (Ar-OH Broad
band), 745 (C–H arom. ortho), 856, 871 (C–H arom. meta),
1
795 (C–H arom. para); HNMR (DMSO-d6, 300 MHz) (δ,
ppm): 12.00 (s, 1H, NH), 7.48 (s, 1H, H-2), 7.40–6.91(m,
3H, H-3, 5 and 6), 7.82 (s, 1H,H, CH), 7.67 (s, 1H, H-2’),
7.58 (m, 2H, H = 5’ and 6’), 9.85 (s, OH), 4.066 (s, 3H,
OCH3); 13C NMR (DMSO-d6, CDCl3): 168.1 (CONH,
amide), 116.2 (C═C, ethylene), 163.2 (C═N, imino), 142.4
(C═C), 128.5 (1C benzene), 111.6 (1C benzene), 116.2 (1C
benzene), 123.2 (1C benzene), 149.7 (1C benzene), 147.1
(C–OH), 56.3 (OCH3), 155.3 (C–N), 123.3(2C benzene),
125.1 (2C benzene), 146.2 (C–NO2); HRMS calcd for
C17H13N3O5S: 371.3672, found 372.3265; Anal. calcd.: C,
56.10; H, 3.92; N, 10.90; found: C, 56.12; H, 3.94; N,
10.93.
2-(4-chlorophenylimino)-5-(4-chlorobenzylidene)-4-
thiazolidinone (24)
Reaction time: 5 h; Off-white crystals (1.05 g, 68%); mp
320–325 °C (dioxane), Rf value: 0.90 (Toluene: Ethanol
8:2), λmax: 263 nm, IR(KBr, cm−1) ν: 1722 (C═O), 3413
(NH str.), 1505 (NH bend), 1247 (C–N), 1605 (C═N), 3051
(C–H arom.), 1649 (C═C), 1091 (Ar–Cl), 732 (C–H arom.
1
ortho), 821 (C–H arom. para); HNMR (DMSO-d6, 300
MHz) (δ, ppm): 10.908 (s, 1H, NH), 7.05–7.46 (m, 4H, H-
2,3,5,6), 7.63 (s, 1H, CH), 7.54–7.78 (m, 4H, H-2’,3’,5’,6’);
13C NMR (DMSO-d6, CDCl3): 168.7 (CONH, amide),
116.4 (C═C, ethylene), 163.1 (C═N), 142.3 (C═C), 133.4
(1C benzene), 129.8 (2C benzene), 128.1 (2C benzene),
133.9 (C–Cl), 147.2 (C–N), 122.3 (2C benzene), 130.4 (2C
benzene), 133.3 (C–Cl); HRMS calcd for C16H10Cl2N2OS:
349.2344, found 349.0219; Anal. calcd.: C, 56.21; H, 3.33;
N, 7.71; found: C, 56.23; H, 3.31; N, 7.74.
2-(4-chlorophenylimino)-5-benzylidene-4-thiazolidinone
(22)
Buff powder (958 mg, 69%); mp 340–342 °C (dioxane), Rf
value: 0.72 (Toluene: Ethanol 8:2), λmax: 346 nm, IR(KBr,
cm−1) ν: 1674 (C═O), 3413 (NH str.), 1564 (NH bend),

Medicinal Chemistry Research
2-(4-chlorophenylimino)-5-(4-hydroxybenzylidene)-4-
thiazolidinone (25)
7.51 (m, 2H, H-2,3,5,6), 8.36 (s, 1H, CH), 8.434 (s, 1H, H-
2’), 8.07 (d, 1H, J = 7.5 Hz, H-4’), 7.57–7.84 (m, H-5’,6’);
13C NMR (DMSO-d6, CDCl3): 168.2 (CONH, amide),
116.4 (C═C, ethylene), 163.1 (C═N), 142.6 (C═C), 136.9
(1C benzene), 122.9 (1C benzene), 129.1 (1C benzene),
134.9 (1C benzene), 147.9 (C–NO2), 123.4 (1C benzene),
147.8 (C–N), 122.3 (2C benzene), 130.2 (2C benzene),
133.4 (C–Cl); HRMS calcd for C16H11ClN2O2S: 359.7869,
found 360.0568; Anal. calcd.: C, 54.62; H, 3.24; N, 11.24;
found: C, 54.61; H, 3.21; N, 11.22.
Brown powder (1.09 g, 75%); mp 235–240 °C (dioxane), Rf
value: 0.71 (Toluene: Ethanol 8:2), λmax = 269 nm, IR(KBr,
cm−1) ν: -C═O 1701; -NH- stretch 3421; -NH- bend 1505;
-C–N 1255; C═N 1575; C–H stretch (aromatic) 2979; C═C
1639; Ar–Cl 1080; Ar-OH 3421 (Broad band); C–H bend
1
(arom. para) 740 and 821; HNMR (DMSO-d6, 300 MHz)
(δ, ppm): 11.268 (s, 1H, NH); 6.85–7.07 (m, 4H, H-
2,3,5,6); 7.897 (s, 1H, CH); 7.23–7.43 (m, 2H, H-2’,6’);
7.730 (d, 2H, J 6.3, H = 3’ and 5’); 10.288 (s, OH); 13C
NMR (DMSO-d6, CDCl3): 168.4 (CONH, amide), 116.9
(C═C, ethylene), 163.5 (C═N), 142.1 (C═C), 127.9 (1C
benzene), 130.9 (2C benzene), 117.1 (2C benzene), 157.9
(C–OH), 147.8 (C–N), 122.6 (2C benzene), 130.2 (2C
benzene), 132.4 (C–Cl); HRMS calcd for C16H11ClN2O2S:
330.7887, found 331.0555; Anal. calcd.: C, 59.21; H, 3.80;
N, 8.12; found: C, 59.19; H, 3.81; N, 8.11.
2-(4-chlorophenylimino)-5-(4-hydroxy-3-
methoxybenzylidene)-4-thiazolidinone (28)
Bright yellow crystals (810 mg, 51%); mp 220–228 °C
(dioxane), Rf value: 0.79 (Toluene: Ethanol 8:2), λmax: 344
nm, IR (KBr, cm−1) ν: 1691 (C═O), 3421 (NH str.), 1263
(C–N), 1505 (C═N), 2974 (C–H arom.), 1647 (C═C), 1091
(Ar–Cl), 3473 (Ar-OH Broad band), 823 (C–H arom. meta),
1
756 (C–H arom. para); HNMR (DMSO-d6, 300 MHz) (δ,
2-(4-chlorophenylimino)-5-(2-nitrobenzylidene)-4-
thiazolidinone (26)
ppm): 10.9 (s, 1H, NH), 6.80–7.45 (4H, H-2,3,5,6), 7.580
(s, 1H, CH), 7.635 (s, 1H, H-2’), 7.63–7.91 (m, 2H, H-
5’,6’), 4.01 (s, 3H, OCH3), 9.770 (s, OH); 13C NMR
(DMSO-d6, CDCl3): 168.9 (CONH, amide), 116.3 (C═C,
ethylene), 163.4 (C═N), 142.5 (C═C), 128.9 (1C benzene),
112.9 (1C benzene), 122.8 (1C benzene), 116.1 (1C ben-
zene), 147.4 (C–OH), 149.9 (1C benzene), 56.9 (OCH3),
147.4 (C–N), 122.9 (2C benzene), 130.6 (2C benzene),
132.4 (C–Cl); HRMS calcd for C17H13ClN2O3S: 360.8147,
found 361.0767; Anal. calcd.: C, 57.68; H, 4.03; N, 7.47;
found: C, 57.66; H, 4.01; N, 7.45.
Rust crystals, (1.05 g, 66%); mp 218–220 °C (dioxane), Rf
value: 0.79 (Toluene: Ethanol 8:2), λmax: 278 nm, IR (KBr,
cm−1) ν: 1678(C═O), 3255 (NH str.), 1500 (NH bend),
1238 (C–N), 1550 (C═N), 2983 (C–H arom.), 1618 (C═C),
1083(Ar–Cl), 1338 (Ar–NO2 Sym), 1517 (Ar–NO2 Asym),
756 (C–H arom. ortho), 821 (C–H arom. para);1HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 11.272 (s, 1H, NH), 7.31–
7.52 (m, 4H, H-2,3,5,6), 7.92 (s, 1H, CH), 7.79 (d, 1H, J =
7.5 Hz, H-3’), 7.76–8.05(m, 2H, H = 4’ and 5’), 7.511 (d,
1H, J = 8.4 Hz, H-6’); 13C NMR (DMSO-d6, CDCl3): 168.2
(CONH, amide), 116.4 (C═C, ethylene), 163.3 (C═N),
142.5 (C═C), 127.4 (2C benzene), 134.1 (1C benzene),
128.6 (1C benzene), 123.8 (1C benzene), 147.9 (C–NO2),
147.6 (C–N), 122.8 (2C benzene), 130.6 (2C benzene),
132.9 (C–Cl); HRMS calcd for C16H11ClN2O2S: 359.7869,
found 360.0568; Anal. calcd.: C, 54.62; H, 3.24; N, 11.24;
found: C, 54.60; H, 3.22; N, 11.21.
2-(3-chlorophenylimino)-5-benzylidene-4-thiazolidinone
(29)
Reaction time 8 h; Brown crystals (1.0 g, 72%); mp 260–
262 °C (from dioxane); Rf value: 0.72 (Toluene: Ethanol,
8:2); λmax 262 nm; IR (KBr, cm−1) ν: -C═O 1679; -NH-
stretch 3267; -NH bend 1504; -C–N 1244; C═N 1595; C–H
stretch (arom.) 3022; C═C 1629; Ar–Cl 1076; C–H bend
(arom. meta) 851 and 875; 1HNMR (DMSO-d6, 300 MHz):
(δ, ppm): 11.31, (S, 1H, NH), 7.509 (s, 1H, H-2), 7.084-
6.985 (m, 3H, H-4,5,6), 7.084 (s, 1H, CH), 7.748–7.509 (m,
5H arom.); 13C NMR (DMSO-d6, CDCl3): 168.1 (CONH,
amide), 116.3 (C═C, ethylene),, 163.5 (C═N), 135.9 (1C
benzene), 142.4 (C═C), 128.9 (2C benzene), 129.2 (2C
benzene), 127.1 (1C benzene), 149.4 (C–N), 120.9 (1C
benzene), 122.1(1C benzene), 134.8 (1C benzene), 127.6
(1C benzene), 131.6 (C–Cl); HRMS calcd for
C16H11ClN2OS: 314.0281, found 315.0583; Anal. calcd.: C,
62.10; H, 3.98; N, 8.52; found: C, 62.11; H, 3.96; N, 8.55.
2-(4-chlorophenylimino)-5-(3-nitrobenzylidene)-4-
thiazolidinone (27)
Buff powder (984 mg, 62%); mp 280–285 °C (dioxane), Rf
value: 0.84 (Toluene: Ethanol 8:2), λmax: 343 nm, IR (KBr,
cm−1) ν: 1681 (C═O), 3263 (NH str.), 1500 (NH bend),
1238 (C–N), 1512 (C═N), 2975 (C–H arom.), 1637 (C═C),
1091 (Ar–Cl), 1349 (Ar–NO2 Sym), 1512 (Ar–NO2 Asym),
1
821 (C–H arom. meta), 745 (C–H arom. para); HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 10.99 (s, 1H, NH), 7.07–

Medicinal Chemistry Research
2-(3-chlorophenylimino)-5-(2-chlorobenzylidene)-4-
thiazolidinone (30)
300 MHz) (δ, ppm): 10.288, (s, 1H, NH), 7.460 (s, 1H, H-
2), 7.56 (d, 1H, J 7.5, H-4), 7.258–7.041 (m, 2H, H-5 and
6), 7.433 (s, 1H, CH), 7.741–7.604 (m, 4H, arom.), 10.181
(s, 1H, OH); 13C NMR (DMSO-d6, CDCl3): 168.5 (CONH,
amide), 116.4 (C═C, ethylene), 163.6 (C═N), 142.6 (C═C),
127.9 (1C benzene), 130.9 (2C benzene), 115.4 (2C ben-
zene), 157.9 (C–OH), 150.2 (C–N), 122.1 (1C benzene),
127.4 (1C benzene), 131.2 (1C benzene), 120.3 (1C ben-
zene), 134.9 (C–Cl); HRMS calcd for C16H11ClN2O2S:
330.0230, found 331.05; Anal. calcd.: C, 59.21; H, 3.80; N,
8.12; found: C, 59.20; H, 3.83; N, 8.10.
Brown crystals (923 mg, 60%); mp 240–242 °C (from
dioxane); Rf value: 0.72 (Toluene: Ethanol, 8:2); λmax 263
nm; IR (KBr, cm−1) ν: -C═O 1722; -NH- stretch 3423; -NH
bend 1509; -C–N 1247; C═N 1599; C–H stretch (arom.)
2966; C═C 1654; Ar–Cl 1039; C–H bend (arom. meta)
862; C–H bend (arom. para) 765.; 1HNMR (DMSO-d6, 300
MHz) (δ, ppm): 11.7 (s, 1H, NH), 7.593 (s, 1H, H-2), 7.204
(d, 1H, J 28.5, H-4), 7.071-6.985 (m, 2H, H-5 and 6), 7.628
(s, 1H, CH), 7.577 (d, 1H, J 3.9, H-3’), 7.923–7.723 (m,
3H, H-4’, 5’, 6’); 13C NMR (DMSO-d6, CDCl3): 165.1
(CONH, amide), 116.4 (C═C, ethylene), 163.2 (C═N),
142.5 (C═C), 133.9 (1C benzene), 127.1 (1C benzene),
126.4 (1C benzene), 129.4 (1C benzene), 129.1 (1C ben-
zene), 134.9 (C–Cl), 150.8 (C–N), 122.4 (1C benzene),
120.9 (1C benzene), 131.6 (1C benzene), 127.6 (1C ben-
zene), 134.8 (C–Cl); HRMS calcd for C16H10Cl2N2OS:
347.9891, found 349.0123; Anal. calcd.: C, 56.21; H, 3.33;
N, 7.71; found: C, 56.23; H, 3.30; N, 7.73.
2-(3-chlorophenylimino)-5-(2-nitrobenzylidene)-4-
thiazolidinone (33)
Dark Brown crystals (1.0 g, 63%); mp 200–205 °C (from
dioxane); Rf value: 0.72 (Toluene: Ethanol, 8:2); λmax 274
nm; IR (KBr, cm−1) ν: -C═O 1685; -NH- stretch 3265; -NH
bend 1523; -C–N 1236; C═N 1598; C–H stretch (arom.)
3062; C═C 1639; Ar–Cl 1091; Ar–NO2 1342(sym) 1523
(asym); C–H bend (arom. meta) 772 and 857; C–H bend
(arom. ortho) 754; 1HNMR (DMSO-d6, 300 MHz) (δ,
ppm): 11.05 (s, 1H, NH), 7.716 (s, 1H, H-2), 7.701 (d, 1H, J
8.7, H-4), 7.687–7.638 (m, 2H, H-5 and 6), 7.497 (s, 1H,
CH), 7.762 (d, 1H, J 13.5, H-3’), 7.884–7.785 (m, 3H,
arom.); 13C NMR (DMSO-d6, CDCl3): 168.3 (CONH,
amide), 116.2 (C═C, ethylene), 163.2 (C═N), 142.4 (C═C),
127.6 (2C benzene), 135.4 (1C benzene), 123.9 (1C ben-
zene), 129.4 (1C benzene), 148.9 (C–NO2), 151.1 (C–N),
123.9 (1C benzene), 128.2 (1C benzene), 121.3 (1C ben-
zene), 132.3 (1C benzene), 135.4 (C–Cl); HRMS calcd for
C16H10ClN3O3S: 359.0131, found 360.0572; Anal. calcd.:
C, 54.62; H, 3.24; N, 11.24; found: C, 54.65; H, 3.22; N,
11.21.
2-(3-chlorophenylimino)-5-(4-chlorobenzylidene)-4-
thiazolidinone (31)
Reaction time 9 h; Brown crystals (1.07 g, 70%); mp 240–
245 °C (from dioxane); Rf value: 0.74 (Toluene: Ethanol,
8:2); λmax 348 nm; IR (KBr, cm−1) ν: -C═O 1672; -NH-
stretch 3265; -NH bend 1463; -C–N 1251; C═N 1631; C–H
stretch (arom.) 3053; C═C 1631; Ar–Cl 1091; C–H bend
1
(arom. meta) 821; C–H bend (arom. para) 763; HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 10.01 (s, 1H, NH), 7.542
(s, 1H, H-2), 7.063 (d, 1H, J 7.5,H-4), 7.45 (d, 2H, J 7.5, H-
5 and 6), 7.633 (s, 1H, CH), 7.633–7.441 (m, 4H, H-2’, 3’,
5’, and 6’); 13C NMR (DMSO-d6, CDCl3): 168.1 (CONH,
amide), 116.6 (C═C, ethylene), 163.4 (C═N), 142.1 (C═C),
133.9 (1C benzene), 129.9 (2C benzene), 128.4 (2C ben-
zene), 133.1 (C–Cl), 150.9 (C–N), 120.9 (1C benzene),
122.4 (1C benzene), 127.6 (1C benzene), 131.6 (1C ben-
zene), 134.8 (C–Cl); HRMS calcd for C16H10Cl2N2OS:
347.9891, found 349.0103; Anal. calcd.: C, 56.21; H, 3.33;
N, 7.71; found: C, 56.22; H, 3.35; N, 7.74.
2-(3-chlorophenylimino)-5-(3-nitrobenzylidene)-4-
thiazolidinone (34)
Brown crystals (1.03 g, 65%); mp 275–280 °C (from diox-
ane); Rf value: 0.72 (Toluene: Ethanol, 8:2); λmax 342 nm;
IR (KBr, cm−1) ν: -C═O 1677; -NH- stretch 3261; -NH
bend 1527; -C–N 1242; C═N 1598; C–H stretch (arom.)
2964; C═C 1629; Ar–Cl 1114; Ar–NO2 1352 (sym) 1510
(asym); C–H bend (arom. meta) 765 and 859; 1HNMR
(DMSO-d6, 300 MHz) (δ, ppm): 11.01 (s, 1H, NH), 7.726
(s, 1H, H-2), 7.611–7.510 (m, 3H, H-4,5 and 6), 7.611 (s,
1H, CH), 7.812 (s, 1H, H-2’), 7.828 (d, 1H, 7.925–7.844
(m, 2H, H-5’ and 6’); 13C NMR (DMSO-d6, CDCl3): 168.5
(CONH, amide), 116.9 (C═C, ethylene), 163.6
(C═N),142.2 (C═C), 137.6 1C benzene), 123.9 (1C ben-
zene), 124.4 (1C benzene), 130.4 (1C benzene), 135.9 (1C
benzene), 149.1 ((C–N), 149.9 (C–N), 123.2 (1C benzene),
120.9 (1C benzene), 127.2 (1C benzene), 131.9 (1C
2-(3-chlorophenylimino)-5-(4-hydroxybenzylidene)-4-
thiazolidinone (32)
Reaction time 7 h; Mustard yellow crystals (1.05 g, 72%);
mp 310–315 °C (from dioxane); Rf value: 0.796 (Toluene:
Ethanol, 8:2); λmax 365 nm; IR (KBr, cm−1) ν: -C═O 1677;
-NH- stretch 3413; -NH bend 1500; -C–N 1244; C═N
1564; C–H stretch (aromatic) 3026; C═C 1650; Ar–Cl
1091; Ar-OH 3469 (Broad band); C–H bend (arom. meta)
825, 850; C–H bend (arom. para) 764; 1HNMR (DMSO-d6,

Medicinal Chemistry Research
benzene), 135.1 (C–Cl); HRMS calcd for C16H10ClN3O3S:
359.0131, found 360.0572; Anal. calcd.: C, 54.62; H, 3.24;
N, 11.24; found: C, 54.60; H, 3.21; N, 11.22.
in PEG 400 was administered orally, 30 min before carra-
geenan injection. Control animals received the same volume
of vehicle. The volume of the paw was measured by a
plethysmometer immediately after the injection. Subsequent
readings of the volume of the same paw were recorded at 1,
2, 4 h intervals and compared with the initial readings. The
percent anti-inflammatory activity was calculated according
to the following formula:
2-(3-chlorophenylimino)-5-(4-hydroxy-3-
methoxybenzylidene)-4-thiazolidinone (35)
Dark brown crystals (955 mg, 60%); mp 225–230 °C (from
dioxane); Rf value: 0.73 (Toluene: Ethanol, 8:2); λmax 375
nm; IR (KBr, cm−1) ν: -C═O 1701; -NH- stretch 3265; -NH
bend 1497; -C–N 1255; C═N 1583; C–H stretch (arom.)
2905; C═C 1641; Ar–Cl 1033; Ar-OH 3425 (Broad band);
C–H bend (arom. meta) 795, 857; C–H bend (arom. para)
Percentage inhibition of edema ¼ð1 À Vt=VcÞ Â 100;
where Vt and Vc are volumes of edema in drug treated and
control groups, respectively.
Statistical analysis was carried out using Graph Pad
Prism 3.0 (Graph Pad Software, San Diego, CA). Sig-
nificance of statistical differences of control and test groups
was verified using analysis of variance (ANOVA) followed
by Dunnett’s test. Values are expressed as mean S.E.M; n
= 6. The compounds were considered to show significant
effect (Table 1).
1
744; HNMR (DMSO-d6, 300 MHz) (δ, ppm): 10.9 (s, 1H,
NH), 7.253 (s, 1H, H-2), 7.580–7.431 (m, 3H, H-4, 5, and
6), 7.045 (s, 1H, CH), 7.301 (s, 1H, H-2’), 3.839 (s, 3H,
OCH3), 9.81 (s, 1H, OH), 7.081-6.966 (d, 2H, H-5’ and 6’);
13C NMR (DMSO-d6, CDCl3): 167.5 (CONH, amide),
114.9 (C═C, ethylene), 162.6(C═N), 142.9 (C═C), 129.6
(1C benzene), 113.9 (1C benzene), 117.4 (1C benzene),
147.4(C–OH), 147.9 (1C benzene), 57.6 (OCH3), 150.1 (C–
N), 123.9 (1C benzene), 123.9 (1C benzene), 129.2 (1C
benzene), 132.5 (1C benzene), 136.1 (C–Cl); HRMS calcd
for C17H13ClN2O3S: 360.0335, found 361.0759; Anal.
calcd.: C, 57.68; H, 4.03; N, 7.47; found: C, 57.66; H, 4.05;
N, 7.45.
Antinociceptive activity
Antinociceptive activity of the test compounds, at a dose of
50 mg/kg, was studied by tail flick method in mice (Davies
et al. 1946; Crofford et al. 1994). Albino mice of either sex,
weighing 25–30 grams, were used for the study. Ibuprofen
40 mg/kg was used as the standard. After oral dose of the
standard and test compounds, reaction time was noted at 0,
1, 2, and 4 h time intervals. Basal reaction time to radiant
heat was taken by placing the tip (last 1–2 cm) of the tail on
the radiant heat source. Withdrawal of the tail from the
source was taken as the end point. A cutoff period of 10–12
s was observed to prevent damage to the tail. All the values
are expressed as means S.E.M. The results were analyzed
by ANOVA (Dunett’s test). Values are expressed as mean
S.E.M; n = 6. The compounds exhibited significant effect
(Table 2).
Pharmacological evaluation
The experiments were performed using Wistar rats of either
sex weighing 100–150 g, and albino mice of either sex
weighing 25–30 g. Standard food pellets and water were
given ad libitum. The animals were acclimatized for 14 days
under laboratory conditions. The animals were maintained
under natural day and night cycle before performing the
tests. Indomethacin and Ibuprofen were used as reference
drugs for anti-inflammatory and antinociceptive activities,
respectively. Test compounds dissolved in polyethylene
glycol PEG 400 were administered orally through suitable
gavages. Ethical clearance was obtained from Institutional
Animal Ethics Committee (IAEC) before performing the
experiments, and the same were conducted as per the Indian
National Science Academy Guidelines (Reg. No.
BBDNITM/IAEC/Clear/04/2010).
Percent protection ¼ðTc À Tt=Ct À TcÞÂ100;
where, Tc is the reaction time in the control group, Tt is the
reaction time in treated mice and Ct is the cutoff time.
Cutoff time was set at 15 seconds to prevent tissue damage.
Acute toxicity studies
Anti-inflammatory activity
The animals were tested for any kind of toxicity of the test
compounds and were observed for 14 days prior to per-
forming the pharmacological studies (Dixion 1985). Title
compounds were found to be non-toxic and were well tol-
erated by the experimental animals. The compounds
showed a high safety margin. The approximate lethal dose
ALD50 of the compounds was found to be >500 mg/kg.
Test compounds were evaluated for anti-inflammatory
activity by carrageenan-induced rat paw edema method
(Davies et al. 1946). The rats received a sub plantar injec-
tion of 0.1 mL saline, containing 1% carrageenan, in the
right hind paw. A suspension of test compounds (50 mg/kg)

Medicinal Chemistry Research
Table 1 Anti-inflammatory
activity of the synthesized
compounds (1–35)
Compound code
Mean paw volume SEM (mL) and % inhibition
Time after carrageenan injection
0 h
1.0 h
2 h
4 h
Control
0.110 0.037
0.110 0.028
0.110 0.032
0.130 0.041
0.140 0.018
0.110 0.022
0.120 0.014
0.130 0.031
0.120 0.022
0.110 0.087
0.120 0.015
0.110 0.034
0.110 0.029
0.120 0.090
0.120 0.045
0.120 0.020
0.120 0.092
0.110 0.057
0.120 0.061
0.110 0.020
0.110 0.031
0.110 0.028
0.120 0.093
0.110 0.030
0.110 0.052
0.120 0.021
0.120 0.045
0.110 0.022
0.110 0.041
0.120 0.020
0.110 0.020
0.110 0.040
0.120 0.038
0.110 0.027
0.120 0.038
0.110 0.038
0.120 0.017
0.550 0.029
0.650 0.031
0.680 0.023
Indomethacin
0.150 0.041 (72.72)
0.280 0.069 (49.09)
0.260 0.072 (52.72)
0.205 0.082 (62.72)
0.550 0.065 (8.33)
0.280 0.029 (49.09)
0.203 0.070 (63.09)
0.270 0.190 (50.90)
0.390 0.050 (29.09)
0.395 0.045 (28.18)
0.370 0.029 (32.72)
0.450 0.061 (18.18)
0.420 0.050 (23.63)
0.365 0.082 (33.63)
0.420 0.014 (23.63)
0.400 0.047 (27.27)
0.385 0.012 (30)
0.210 0.024 (67.69)
0.330 0.054 (49.23)
0.320 0.045 (50.77)
0.270 0.076 (62.85)
0.480 0.053 (36.00)
0.275 0.034 (57.69)
0.380 0.450 (45.71)
0.260 0.034 (57.69)
0.510 0.082 (21.53)
0.500 0.032 (23.07)
0.490 0.041 (24.61)
0.540 0.042 (16.92)
0.520 0.020 (20)
0.210 0.028 (69.11)
0.340 0.032 (50.00)
0.335 0.032 (50.73)
0.280 0.065 (58.82)
0.480 0.047 (36.00)
0.270 0.043 (60.29)
0.360 0.043 (52.00)
0.265 0.023 (61.02)
0.530 0.062 (22.06)
0.520 0.064 (23.53)
0.500 0.028 (26.47)
0.550 0.071 (19.11)
0.530 0.055 (22.06)
0.510 0.012 (25)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
0.500 0.059 (23.07)
0.520 0.042 (20)
0.500 0.031 (26.47)
0.520 0.039 (23.53)
0.505 0.020 (25.73)
0.465 0.052 (31.61)
0.565 0.069 (16.91)
0.510 0.014 (25)
0.520 0.025 (20)
0.500 0.065 (23.07)
0.465 0.070 (28.46)
0.560 0.030 (13.84)
0.510 0.079 (21.54)
0.480 0.039 (26.15)
0.470 0.045 (27.69)
0.285 0.059 (56.15)
0.280 0.028 (56.92)
0.270 0.045 (58.46)
0.485 0.060 (25.38)
0.260 0.081 (60)
0.360 0.065 (34.54)
0.460 0.034 (16.36)
0.400 0.028 (27.27)
0.370 0.021 (32.73)
0.390 0.014 (29.09)
0.254 0.040 (53.81)
0.220 0.050 (60)
0.480 0.082 (29.41)
0.485 0.019 (28.67)
0.290 0.025 (57.35)
0.270 0.040 (60.29)
0.270 0.041 (60.29)
0.490 0.082 (27.94)
0.270 0.055 (60.29)
0.310 0.028 (58.66)
0.270 0.022 (60.29)
0.300 0.020 (55.88)
0.290 0.039 (57.37)
0.290 0.049 (57.35)
0.500 0.089 (26.47)
0.310 0.037 (54.41)
0.295 0.026 (56.61)
0.330 0.051 (51.47)
0.218 0.024 (60.36)
0.410 0.050 (25.45)
0.240 0.041 (56.36)
0.190 0.041 (60)
0.320 0.042 (50.77)
0.270 0.081 (58.46)
0.290 0.041 (55.38)
0.280 0.048 (56.92)
0.275 0.019 (57.69)
0.480 0.028 (26.15)
0.285 0.039 (56.15)
0.280 0.018 (56.92)
0.330 0.073 (49.23)
0.242 0.020 (55)
0.240 0.075 (56.36)
0.235 0.091 (57.27)
0.190 0.027 (60)
0.490 0.041 (10.90)
0.225 0.056 (59.09)
0.220 0.023 (60)
0.260 0.059 (52.72)
Value in parenthesis indicate percent inhibition
Antioxidant activity
Molecular docking studies
Methodology
The test compounds were evaluated for in vitro free radical
scavenging capacity at concentrations of 2, 4, 6, 8, and 10
µg/mL in methanol through Diphenyl-1-picrylhydrazyl
(DPPH) assay method (Mensor et al. 2001; Oyaizu 1986;
Soare et al. 1997). The reduction capability of DPPH radical
is determined by a decrease in its absorbance at 517 nm
induced by antioxidants. The compounds showed promising
antioxidant activity in comparison to ascorbic acid as the
standard (Table 3).
The molecular docking studies were performed on the
human COX-2 (PDB ID: 5KIR), which contains rofecoxib
(Vioxx) as co-crystallized ligand. The resolution of the
protein was found to be 2.69 Å (Orlando and Malkowski
2016). The protein preparation was done using the protein
preparation wizard of Maestro (version 11.1) program
available in the Schrodinger software. Hydrogen atoms
were added and bond orders were assigned to the protein–
ligand complex at a consistent physiological pH (7.0). The

Medicinal Chemistry Research
Table 2 Antinociceptive activity
of the synthesized compounds
(1–35)
Compound
code
Flicking time (seconds)
0.5 h
1 h
2.55 0.061
2 h
4 h
2.55 0.069
Control
Ibuprofen
1
2.51 0.018
2.40 0.070
5.5 0.074 (54.36) 8.0 0.074 (68.12) 9.9 0.081 (75.75) 10.05 0.077 (74.63)
3.1 0.030 (19.35) 3.9 0.017 (34.61) 4.5 0.037 (46.66)
4.0 0.033 (37.25) 4.5 0.059 (43.33) 5.2 0.049 (53.84)
4.3 0.098 (41.62) 4.9 0.020 (47.95) 5.5 0.037 (56.36)
5.5 0.093 (53.63)
5.9 0.022 (56.77)
6.1 0.038 (58.19)
4.9 0.034 (47.96)
6.2 0.018 (58.87)
6.4 0.028 (60.15)
5.0 0.021 (49)
2
3
4
2.6 0.032 (3.46)
3.2 0.022 (20.31) 4.5 0.081 (46.66)
5
4.2 0.033 (40.23) 5.6 0.038 (54.46) 6.0 0.020 (60)
4.5 0.037 (44.22) 5.2 0.048 (50.96) 6.1 0.037 (60.65)
3.7 0.036 (32.16) 4.2 0.044 (39.28) 4.9 0.027 (51.02)
2.55 0.013 (1.56) 3.35 0.090 (23.88) 4.5 0.010 (46.66)
6
7
8
4.5 0.029 (43.33)
4.9 0.063 (47.96)
6.2 0.047 (58.87)
4.5 0.070 (43.33)
5.3 0.082 (51.88)
6.8 0.091 (62.5)
9
2.55 0.046 (1.56) 2.65 0.039 (3.77)
4.7 0.042 (48.94)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
5.0 0.042 (50) 5.3 0.062 (51.88) 6.0 0.049 (60)
3.5 0.040 (28.28) 3.8 0.071 (32.89) 4.12 0.08 (41.74)
3.9 0.071 (35.64) 4.85 0.060 (47.42) 5.1 0.060 (52.94)
5.45 0.06 (54.13) 6.09 0.071 (58.13) 6.5 0.043 (63.07)
4.5 0.071 (44.44) 4.99 0.062 (48.90) 5.59 0.071 (57.07) 6.03 0.072 (57.71)
2.8 0.045 (10.71) 3.5 0.062 (27.14) 4.2 0.011 (42.86)
3.12 0.061 (19.55) 3.95 0.065 (35.44) 5.12 0.042 (53.12)
4.9 0.062 (47.96)
6.3 0.022 (59.52)
6.75 0.062 (62.22)
5.0 0.028 (49)
5.0 0.024 (50)
5.95 0.062 (57.14) 6.25 0.051 (61.6)
2.55 0.042 (1.57) 2.99 0.046 (14.71) 4.5 0.051 (47.25)
3.8 0.044 (33.94) 4.2 0.051 (39.28) 5.0 0.046 (52)
4.2 0.091 (40.24) 5.5 0.062 (53.63) 6.2 0.012 (61.29)
6.2 0.099 (58.87)
6.8 0.064 (62.5)
3.9 0.049 (35.64) 4.2 0.011 (39.28) 5.4 0.092 (55.55) 5.95 0.066 (57.14)
4.0 0.064 (37.25) 5.5 0.020 (53.63) 6.2 0.072 (61.29)
5.4 0.070 (53.51) 6.5 0.041 (60.77) 6.7 0.021 (64.17)
5.9 0.040 (57.45) 6.6 0.021 (61.36) 6.8 0.070 (64.7)
3.5 0.020 (28.28) 4.0 0.059 (36.25) 4.2 0.06 (42.85)
6.9 0.062 (63.04)
7.0 0.041 (63.57)
7.1 0.064 (64.08)
4.5 0.070 (43.33)
6.6 0.082 (61.36)
7.1 0.040 (64.08)
6.2 0.070 (58.87)
6.8 0.047 (62.5)
6.8 0.028 (62.5)
6.9 0.037 (63.04)
5.0 0.037 (49)
4.0 0.070 (37.25) 5.0 0.099 (49)
5.5 0.029 (53.63)
6.3 0.080 (60.16) 6.7 0.040 (61.94) 6.8 0.050 (64.7)
4.0 0.040 (37.25) 4.5 0.042 (43.33) 5.0 0.044 (52)
3.5 0.038 (28.57) 4.5 0.031 (43.33) 5.1 0.039 (52.94)
4.8 0.038 (47.91) 5.3 0.037 (51.88) 6.0 0.031 (60)
5.2 0.027 (51.92) 5.8 0.018 (56.03) 6.3 0.032 (61.90)
3.2 0.026 (21.87) 4.1 0/037 (37.80) 4.5 0.021 (46.66)
2.7 0.038 (7.40)
2.9 0.022 (12.06) 3.0 0.082 (20)
3.5 0.038 (27.14)
7.2 0.031 (64.58)
4.2 0.047 (39.28)
5.8 0.030 (56.89) 6.2 0.028 (58.87) 6.7 0.031 (64.17)
3.0 0.021 (16.66) 3.2 0.077 (20.31) 4.0 0.011 (40)
Value in parenthesis indicate percent protection
optimization of the interactions between the side chains and
ligand with side chains was done. The energy minimization
of the X-ray structure was done at the root mean square
deviation value of 0.3 Å. This energy minimization also
ensured the placement of hydrogen atoms in an optimized
geometry (Friesner et al. 2006). The ligand preparation was
done using the Ligprep module where the SDF files of the
imported ligands were generated for their isomers,
tautomers, with a maximum of 10 conformations for each
ligand using latest OPLS3 force field (Glide 2018; Ligprep
2018; Harder et al. 2015). The minimized structure of the
enzyme was subjected to the grid generation module where
the active site of the enzyme was taken into consideration
and a grid was prepared for the docking of the ligands. The
docking studies were performed using Ligand Docking
module which takes up grid as a grid file and ligprep file to

Medicinal Chemistry Research
Table 3 Free radical scavenging
activity of the synthesized
compounds (1–35)
Compound
code
Absorbance at 517 nm
IC50 μg/
mL
2 μg/mL
4 μg/mL
6 μg/mL
8 μg/mL
10 μg/mL
Control
0.698
0.698
0.698
0.698
0.698
–
Ascorbic acid
0.363 (47.96) 0.279 (59.95) 0.228 (67.36) 0.182 (73.96) 0.112 (83.96) 1.06
0.471 (32.52) 0.419 (39.94) 0.377 (46.02) 0.298 (57.23) 0.270 (61.30) 3.35
0.444 (36.39) 0.412 (41.01) 0.342 (50.98) 0.279 (59.97) 0.210 (69.93) 2.81
0.439 (37.01) 0.412 (40.95) 0.307 (55.98) 0.251 (64.02) 0.211 (69.81) 2.60
0.412 (40.91) 0.397 (43.09) 0.307 (55.99) 0.250 (64.10) 0.209 (70.01) 2.39
0.475 (32.01) 0.398 (42.89) 0.350 (49.80) 0.295 (57.73) 0.231 (66.92) 3.01
0.489 (30.01) 0.433 (37.99) 0.313 (55.18) 0.251 (64.02) 0.209 (70.07) 2.86
0.404 (42.03) 0.389 (44.19) 0.340 (51.28) 0.265 (62.01) 0.202 (71.06) 2.46
0.461 (34.03) 0.351 (49.63) 0.286 (58.96) 0.277 (60.28) 0.206 (70.48) 2.44
0.481 (31.03) 0.412 (40.96) 0.342 (51.03) 0.278 (60.19) 0.243 (65.23) 3.04
0.445 (36.23) 0.409 (41.29) 0.318 (54.36) 0.265 (62.03) 0.209 (69.98) 2.68
0.415 (40.54) 0.391 (43.98) 0.311 (55.36) 0.286 (59.03) 0.209 (69.99) 2.49
0.442 (36.64) 0.402 (42.36) 0.346 (50.39) 0.279 (59.99) 0.240 (65.59) 2.87
0.489 (29.94) 0.428 (38.65) 0.317 (54.56) 0.242 (65.36) 0.182 (73.97) 2.78
0.412 (40.99) 0.351 (49.69) 0.335 (52.03) 0.278 (60.16) 0.209 (69.95) 2.33
0.499 (28.51) 0.463 (33.66) 0.356 (48.99) 0.316 (54.73) 0.244 (65.00) 3.41
0.459 (34.23) 0.381 (45.36) 0.333 (52.32) 0.279 (60.03) 0.265 (62.01) 2.88
0.521 (25.32) 0.446 (36.09) 0.419 (39.99) 0.380 (45.55) 0.307 (56.03) 4.33
0.442 (36.69) 0.370 (46.98) 0.321 (53.94) 0.279 (60.03) 0.263 (62.36) 2.64
0.488 (30.05) 0.442 (36.66) 0.405 (42.03) 0.358 (48.65) 0.307 (56.03) 4.14
0.482 (30.89) 0.420 (39.82) 0.401 (42.55) 0.352 (49.56) 0.282 (59.65) 3.82
0.428 (38.65) 0.351 (49.69) 0.295 (57.69) 0.279 (60.05) 0.248 (64.5) 2.33
0.539 (22.77) 0.453 (35.03) 0.433 (37.99) 0.425 (39.04) 0.418 (40.08) 6.89
0.544 (22.06) 0.487 (30.26) 0.453 (35.03) 0.419 (39.96) 0.411 (41.11) 6.41
0.530 (24.07) 0.492 (29.56) 0.472 (32.36) 0.454 (34.96) 0.402 (42.36) 6.52
0.488 (30.03) 0.403 (42.32) 0.346 (50.43) 0.273 (60.89) 0.242 (65.36) 3.02
0.557 (20.20) 0.517 (25.93) 0.465 (33.38) 0.453 (35.10) 0.418 (40.03) 6.91
0.552 (20.91) 0.539 (22.78) 0.517 (25.93) 0.432 (38.11) 0.374 (46.36) 5.9
0.449 (35.65) 0.391 (43.98) 0.304 (56.42) 0.241 (65.53) 0.211 (69.79) 2.52
0.552 (21.04) 0.523 (24.99) 0.497 (28.82) 0.476 (31.83) 0.438 (37.29) 8.4
0.541 (22.57) 0.513 (26.54) 0.486 (30.29) 0.449 (35.72) 0.426 (38.99) 7.56
0.506 (27.65) 0.469 (32.80) 0.437 (37.37) 0.419 (39.99) 0.402 (42.39) 6.81
0.437 (37.36) 0.401 (42.29) 0.352 (49.50) 0.333 (52.29) 0.318 (54.48) 3.64
0.476 (31.83) 0.443 (36.49) 0.419 (39.99) 0.398 (42.91) 0.376 (46.19) 5.99
0.481 (31.18) 0.433 (37.99) 0.400 (42.65) 0.342 (50.92) 0.321 (53.98) 4.14
0.411 (41.01) 0.399 (42.83) 0.363 (47.91) 0.332 (52.39) 0.288 (58.70) 3.32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Value in parenthesis indicate percent inhibition
generate the scores for the generated conformations by
ligand binding to the active site in comparison with the
standard, rofecoxib. The scores generated were the glide
scores that comprise of the interactions between protein and
ligand. These interactions include the van der Waals (vdW)
(contact term), a Coulomb (Coul) (electrostatic), the H
Bond (hydrogen bond), the Lipo term (lipophilic), the Metal
(metal), the RotB (penalty for freezing rotatable bonds), the
BuryP (penalizes buried polar groups) and Site (polar group
in the active site) interactions. The conformations with good
scores were generated.
Compound portrayed interaction in rofecoxib binding site
of human COX-2
The recognition pattern for the most potent investigational
compounds 23, 24, 26, 30, and 31 identified as COX-2
inhibitors, molecular docking based experiments were

Medicinal Chemistry Research
Fig. 1 The binding pattern of the
active molecules 23, 24, 26, 30,
31. a and inactive molecules b in
the COX-2 active site
rofecoxib. The planar ring A, containing a chloro group,
was observed to be aligned parallel to the ARG120 residue
and π-cation interactions were observed. Hydrogen bonding
was observed between the NH group of ligand and O group
of TYR355 amino acid residue and also perpendicular π–π
stacking interactions were observed between ring A and
TYR355. PHE518 ring energetically favors the π-anion
interactions with the ring B. Similar type of π–π interactions
were observed in the COX-2 active site residues TRP387
and TYR385 with ring C of compound 30 (Fig. 3).
The binding of the active molecule 30 and favorable
interactions have been shown in the Fig. 3a, b. The com-
parative study has been made between the active and
inactive pattern. The docking score of the active compounds
are enumerated in Table 4.
Fig. 2 The binding pattern of the rofecoxib (green), and active mole-
cule 30 (purple), 24 (pink), in the COX-2 active site
Prediction of physiochemical parameters
conducted using Glide module of Mastero 11.1 (Licensed
Version 2017) (Maestro 2018). The docking study on the
COX-2 was performed to investigate the binding pattern of
the potent identified COX-2 inhibitors. The flexible docking
experiment was performed using glide module of the
MAESTRO 11.1 (Maestro 2018). It was observed that the
active compound 30 best fitted to the rofecoxib COX-2
active site. The active site residues and binding pattern of
the active molecules was found to be similar to that of the
standard, rofecoxib. The active molecules were found to be
having B (thiazole ring) binding as the planar (Fig. 1a)
while in the inactive molecules the ring B was tilted (Fig.
1b). The binding pattern thus clarifies the differences
between the active and inactive molecules.
The interactions with the binding site residues and
compound 30 in the active site have been found to be
similar to that of rofecoxib (Fig. 2).
The binding pattern not only gave an idea about the
arrangement of the molecule in the active site but also
picturized important interactions between the molecules and
actives site residues. It was observed that similar types of
interactions were observed for the active molecule 30 and
The compounds synthesized were predicted for the phar-
maceutical properties with the help of QikProp module in
MAESTRO 11.4 (1) (Schrödinger 2018). The pharmaceu-
tical properties include Lipinski rule of 5 and other para-
meters such as bioavailability and pharmacokinetics, etc.
The module suggested that all the compounds followed the
Lipinski rule of 5. Moreover, the partition coefficient
(QPlogPo/w) predicted was in the normal range, i.e. −2.0 to
6.5. For all the synthesized compounds, the QPlogPo/w was
found to be 1.5–4.5. QPPCaco represents the gut cell
absorption of the compounds and ranges from 25 to 500 for
poor gut absorbed compounds while > 500 for the com-
pounds with good gut absorption. Some of the compounds
were predicted to have poor gut absorption, such as com-
pound 10, 11, 14, 17, 18, and 26 (Table 5). The human oral
absorption depends on the number of rotatable bonds,
number of metabolites, logP, cell permeability, and solu-
bility. The number 1 depicts low oral absorption, 2 repre-
sents medium oral absorption, and 3 represents normal oral
absorption. The percentage of normal oral absorption ranges
from 70 to 100%. It was observed that all the compounds
had normal oral absorption.

Medicinal Chemistry Research
Fig. 3 aThe binding pattern and
the important active site
interactions of the active
molecule 30 (purple), in the
COX-2 active site (3D view). b
2D representation of binding
pattern of the active molecule 30
in COX-2 active site
Results and discussion
spectra of synthesized compounds, arising owing to the
nitro and the chloro groups. The observed peaks in IR
spectra (cm−1) of lactam -NH at 3200, 1550, C═O at 1670
Novel 2-(substituted phenyl imino)-5-benzylidene-4-thia-
zolidinones, having different substitutions at imino phenyl
and arylidene groups, have been synthesized and evaluated
in this study. The bathochromic shift attributable to C═N
chromophoric group was obtained at 285–375 nm in the UV
1
and C═C at 1633 agreed with the structures. In HNMR
spectra (δ, ppm), -NH proton observed at 11.8–12.7 showed
substitution at 2nd position instead of 3rd position, which
could be attributed to a lactam proton (Vicini et al. 2008;

Medicinal Chemistry Research
Table 4 Active compounds
interactions and their respective
Investigational compound
Docking score
Important amino acids involved
docking scores and interactions
30
−9.515
−9.133
−9.121
−8.655
−8.539
−9.583
ARG120, TYR355, PHE518, TRP387, TYR385
ARG120, TYR355, PHE518, TRP387, TYR385
ARG120, TYR355, PHE518, TRP387, TYR385
ARG120, TYR355, PHE518, TRP387, TYR385
ARG120, TYR355, PHE518, TRP387, TYR385
ARG513, TYR355, PHE518, TRP387
24
23
31
26
Rofecoxib
Table 5 Important physiochemical properties of the compounds
S. No
Compound
M.W
Volume of compound
Donors
Acceptor
QPlogP o/w
QPPcaco
oral abs
% oral abs
1
4
348.779
378.805
359.786
341.341
371.367
359.786
341.341
349.234
349.234
330.788
359.786
360.814
349.234
349.234
330.788
991.333
1064.717
1031.093
1010.535
1084.997
1031.799
1007.546
998.528
1000.5
2
2
1
2
2
1
2
1
1
2
1
2
1
1
2
4.75
5.5
4.5
5.25
6
3.343
3.439
3.435
2.265
2.386
3.085
1.989
4.302
4.382
3.132
3.151
3.24
558.75
578.154
272.375
81.356
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
95.691
96.518
90.644
74.403
75.786
86.531
71.196
100
2
7
3
10
11
14
17
18
23
24
25
26
28
30
31
32
4
5
88.741
6
5
208.896
66.306
7
5.75
4
8
1724.964
1764.485
565.347
280.612
579.644
1723.781
1760.552
564.372
9
4
100
10
11
12
13
14
15
974.724
1025.969
1049.95
998.565
1001.13
975.016
4.75
5
94.548
89.211
95.374
100
5.5
4
4.302
4.385
3.134
4
100
4.75
94.543
Bruno et al. 2002; Ishida et al. 1990; Momose et al. 1991).
The presence of methine hydrogen (=CH) at 7.70–7.75
further confirmed the proposed structure. The HRMS
characterization of the synthesized compounds further
confirmed the success of synthesis. The compounds were
formed through amino-imino tautomerism involving het-
eroaryl thiazolidinones and their benzylidene derivatives
(Scheme 2) and E/Z isomerism of final compounds was
60.29%, 61.02%, 60.09%, 60.29%, 60.29%, 60.29%,
respectively) being comparable to the standard, Indo-
methacin (10 mg/kg) i.e., 69.11%. Moreover, most of the
compounds exhibited significant antinociceptive activity,
comparable to the standard drug, Ibuprofen (20 mg/kg).
Promising free-radical scavenging activity was recorded for
the synthesized compounds when compared with the stan-
dard. Acute toxicity studies were carried out as per OECD
guidelines and ALD50 of the compounds was > 500 mg/kg
(Dixion 1985). The selected test dose (50 mg/kg) was
decided on the basis of ALD50 value, i.e., 1/10th of the
determined LD50 (500 mg/kg).
Compounds (22–28) formed by the reaction of p-chloro
aniline were found to possess more potential in the series.
Among the synthesized compounds, it was observed that
substitution at the arylidene ring influenced the activity.
Structure activity relationship studies revealed that aryli-
dene ring containing electron withdrawing groups like -Cl
and -NO2 demonstrated better anti-inflammatory activity
than electron donating groups like -OH and -OCH3. Posi-
tions of these groups also affected the activity, with -Cl at
para and -NO2 at meta positions showing maximum activ-
ity. The findings matched well with the previous reports on
1
studied on the basis of HNMR and IR spectral data, and
confirmed on the basis of literature.
Compounds (1–35) were evaluated for anti-inflamma-
tory, antinociceptive, and antioxidant activities. Anti-
inflammatory activity was evaluated in vivo by
carrageenan-induced rat paw edema model (Winter et al.
1962) at a dose of 50 mg/kg (per oral), whereas anti-
nociceptive activity was carried out in vivo using tail flick
method (Davies et al. 1946; Dandiya and Menon 1963) at a
dose of 50 mg/kg (per oral) while antioxidant screening was
done in vitro at concentrations of 2, 4, 6, 8, and 10 µg/mL
using DPPH assay method (George et al. 2008). The results
are shown in Tables 2–4. The compounds have shown
varying degree of anti-inflammatory activity ranging from
16.91% to 61%; some compounds (5, 7, 23, 24, 26, 28 with

Medicinal Chemistry Research
Scheme 2 Mechanism of
formation and existence of 3–7
and their tautomers
the same nucleus (Ottana et al. 2005; Crofford et al. 1994).
Electron withdrawing groups like -Cl and -NO2 demon-
strated better activity than electron donating groups like
-OH and -OCH3. Chloro group at the para position led to
more active compounds (3, 10, 17, 24, 31) while nitro group
at the meta position also behaved in the same manner (6, 13,
20, 27, 34). Compound 7 proved to be the most potent with
the highest anti-inflammatory activity (61.02%). Anti-
nociceptive activity was not much affected by the presence
of electron withdrawing or electron-releasing groups.
Compounds 6, 13, 17, 20, 22, 23, 24, 26, 27, 29, 30, 31, and
34 showed significant antinociceptive activity. The activity
did not vary much with substituents on the arylidene ring.
However, the compounds (22–28) starting from 4-chloro
aniline proved to be more potent antinociceptive agents than
the other synthesized derivatives. Compounds with p-chloro
(24) and m-nitro (27) groups at arylidene ring proved to be
the most potent with the highest antinociceptive activity
(64%). Compounds (1–7) with Cl and F groups on benzene
ring attached to imino group at position-2 showed

Medicinal Chemistry Research
maximum antiinflammatory–antinociceptive activity. It has
been reported that 5-arylidene 4-thiazolidinones act as anti-
inflammatory agents by inhibiting COX-2 enzyme (Ottana
et al. 2005). Thus, the mechanism of action of the synthe-
sized compounds may also be through COX-2 inhibition.
The synthesized compounds exhibited the potential to
scavenge free radicals in varying capacities in the DPPH
assay. Activity was influenced by substitutions on arylidene
moeity present at position-5 of the 4-thiazolidinone nucleus.
Compounds with hydroxy substitution, either alone or in
addition to a methoxy group, emerged as better antioxidants
in every series (4, 7, 11, 14, 18, 21, 25, 28, 32, and 35). This
superiority may be due to the presence of electron cloud on
the aryl rings which can easily donate electron to DPPH.
The free-radical scavenging activity of the synthesized
compounds, which lack hydroxy or methoxy group is
attributable to the presence of free NH group at position-3
and unsaturated double bonds, which can donate hydrogen
and electrons, respectively. Similar findings have been
reported by Hossain and Bhattacharya (Hossain and Bhat-
tacharya 2007). Donation of hydrogen leaves the com-
pounds in their radical form and their structure gets
stabilized owing to electronic conjugation, thus favouring
the reaction to occur. Tominaga et al. (2005) have reported
that the presence of free hydroxyl group in the aryl moiety
is one of the factors in determining the DPPH-scavenging
activity of the compound, where protection of the free-
hydroxyl group drastically reduces the DPPH-scavenging
activity. IC50 of the synthesized derivatives was also cal-
culated and compounds 4, 14, and 21 were found to be the
most potent antioxidant agents, with IC50 (2.39, 2.33, 2.33
µg/mL) comparable to ascorbic acid (1.08 µg/mL). The
docking study on COX-2 was performed to investigate the
binding pattern of the potent identified COX-2 inhibitors. It
was observed that the active compound 30 best fits to the
rofecoxib COX-2 active site. The active site residues and
binding pattern of the active molecules was found to be
similar to the standard, rofecoxib. The active molecules
were found to be having B (thiazole ring) binding in the
planar (Fig. 1a), whereas in the inactive molecules the ring
B was tilted (Fig. 1b). The binding pattern thus clarifies the
differences between the active and inactive molecules. The
interactions with the binding site residues and compound 30
in the active site have been found to be similar to that of
rofecoxib (Fig. 2).
compounds showed promising anti-inflammatory, anti-
nociceptive, and free-radical scavenging activities. Docking
studies revealed that the interactions with the binding site
residues and compound 30 in the active site have been
found to be similar to that of rofecoxib. The planar ring A
containing chloro group was observed to be aligned parallel
to the ARG120 residue and π-cation interactions were
observed. Hydrogen bonding has been observed between
the NH group of ligand and O group of TYR355 amino-acid
residue and also perpendicular π–π stacking interactions
were observed between ring A and TYR355. PHE518 ring
energetically favors the π-anion interactions with the ring B.
Similar type of π–π interactions were observed in the COX-
2 active site residues TRP387 and TYR385 with ring C of
compound 30. As neurodegenerative disorders including
inflammation may be associated with free radicals like
reactive oxygen species, compounds containing both or
either of these activities may prove to be very useful. Drugs
possessing both activities can help in better patient com-
pliance. These compounds exhibit potential to counter three
diseases at the same time none of them had an acidic group,
thereby being non-ulcerogenic. The outstanding properties
of these compounds may open new horizons for further
studies at molecular level to ascertain their mode of action.
Acknowledgements The authors are thankful to Central Drug
Research Institute (CDRI) India for spectral characterization.
Compliance with ethical standards
Conflict of interest The authors declare no conflict of interest.
Publisher’s note: Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations.
References
Bhandari SV, Bothara KG, Patil AA, Chitre TS, Sarkate AP, Gore ST,
Dangre SC, Khachane CV (2009) Design, synthesis and phar-
macological screening of novel antihypertensive agents using
hybrid approach. Bioorg Med Chem 17:390–400
Bhati SK, Kumar A (2008) Synthesis of new substituted azetidinoyl
and thiazolidinoyl-1, 3, 4-thiadiazino (6, 5-b) indoles as pro-
mising anti-inflammatory agents. Eur J Med Chem 43:2323–2330
Bruno G, Costantino L, Curinga C, Maccari R, Monforte F, Nicolo F,
Ottana R, Vigorita M (2002) Synthesis and aldose reductase
inhibitory activity of 5-arylidene-2, 4-thiazolidinediones. Bioorg
Med Chem 10:1077–1084
Chakraborti AK, Garg SK, Kumar R, Motiwala HF, Jadhavar PS
(2010) Progress in COX-2 inhibitors: a journey so far. Curr Med
Chem 17:1563–1593
Conclusions
Chawla P, Singh R, Saraf SK (2012a) Effect of chloro and fluoro
groups on the antimicrobial activity of 2, 5-disubstituted 4-thia-
zolidinones: a comparative study. Med Chem Res 21:3263–3271
Chawla P, Singh R, Saraf SK (2012b) Syntheses and evaluation of 2,
5-disubstituted 4-thiazolidinone analogues as antimicrobial
agents. Med Chem Res 21:2064–2071
A total of 35 2,5-disubstituted 4-thiazolidinones (1–35)
have been synthesized and evaluated for in vivo anti-
inflammatory, antinociceptive activities and in vitro free-
radical scavenging properties using standard protocols. The

Medicinal Chemistry Research
Clarkson PM, Tremblay I (1988) Exercise-induced muscle damage,
repair, and adaptation in humans. J Appl Physiol 65:1–6
Crofford LJ, Wilder RL, Ristimäki A, Sano H, Remmers EF, Epps
HR, Hla T (1994) Cyclooxygenase-1 and-2 expression in rheu-
matoid synovial tissues. Effects of interleukin-1 beta, phorbol
ester and corticosteroids. J Clin Investig 93:1095–1101
Dandiya P, Menon M (1963) Studies on central nervous system
depressants.(III). Influence of some tranquillizing agents on
morphine analgesia. Arch Int Pharmacodyn Ther 141:223
Davies O, Raventos J, Walpole A (1946) A method for the evaluation
of analgesic activity using rats. Br J Pharmacol 1:255–264
Dixion W (1985) The up and down method or small samples. J Am
Stat Assoc 60:967–978
Flohe L, Beckmann R, Giertz H, Loschen G (1985) Oxygen-centered
free radicals as mediators of inflammation. In: Sies H (ed). Oxi-
dative stress. Academic Press, London, p 403–436
Friesner RA, Murphy RB, Repasky MP, Frye LL, Greenwood JR,
Halgren TA, Sanschagrin PC, Mainz DT (2006) Extra precision
glide: Docking and scoring incorporating a model of hydrophobic
enclosure for protein− ligand complexes. J Med Chem 49:6177–
6196
Omar K, Geronikaki A, Zoumpoulakis P, Camoutsis C, Soković M,
Ćirić A, Glamočlija J (2010) Novel 4-thiazolidinone derivatives
as potential antifungal and antibacterial drugs. Bioorg Med Chem
18:426–432
Orhan H, Şahin G (2001) In vitro effects of NSAIDS and para-
cetamolon oxidative stress-related parameters of human ery-
throcytes. Exp Toxicol Pathol 53:133–140
Orlando BJ, Malkowski MG (2016) Crystal structure of rofecoxib
bound to human cyclooxygenase-2. Sect Acta Crystallogr F
Struct Biol Comm 72:772–776
Ottana R, Maccari R, Barreca ML, Bruno G, Rotondo A, Rossi A,
Chiricosta G, Di Paola R, Sautebin L, Cuzzocrea S (2005) 5-
Arylidene-2-imino-4-thiazolidinones: design and synthesis of
novel anti-inflammatory agents. Bioorg Med Chem 13:4243–
4252
Ottanà R, Maccari R, Ciurleo R, Vigorita MG, Panico AM, Cardile V,
Garufi F, Ronsisvalle S (2007) Synthesis and in vitro evaluation
of 5-arylidene-3-hydroxyalkyl-2-phenylimino-4-thiazolidinones
with antidegenerative activity on human chondrocyte cultures.
Bioorg Med Chem 15:7618–7625
Oyaizu M (1986) Studies on products of browning reaction, Jpn. J
Nutr Diet 44:307–315
Panico AM, Vicini P, Geronikaki A, Incerti M, Cardile V, Crascì L,
George S, Parameswaran MK, Chakraborty R, Ravi TK (2008)
Synthesis and evaluation of the biological activities of some 3-{[5-
(6-methyl-4-aryl-2-oxo-1, 2, 3, 4-tetrahydropyrimidin-5-yl)-1, 3,
4-oxadiazol-2-yl]-imino}-1, 3-dihydro-2H-indol-2-one deriva-
tives. Acta Pharm 58:119–129
Messina R, Ronsisvalle
S
(2011) Heteroarylimino-4-
thiazolidinones as inhibitors of cartilage degradation. Bioorg
Chem 39:48–52
Geronikaki AA, Lagunin AA, Hadjipavlou-Litina DI, Eleftheriou PT,
Filimonov DA, Poroikov VV, Alam I, Saxena AK (2008)
Computer-aided discovery of anti-inflammatory thiazolidinones
with dual cyclooxygenase/lipoxygenase inhibition. J Med Chem
51:1601–1609
Saldanha L, Elias G, Rao M (1990) Oxygen radical scavenging
activity of phenylbutenones and their correlation with anti-
inflammatory activity. Arzneimittelforschung 40:89–91
Schrödinger (2018) Release 2018-4. QikProp, Schrödinger, LLC, New
York, NY
Glide (2018) Schrödinger Release 2018-1. Schrödinger, LLC, New
York, NY
Halliwell B, Gutteridge JM (2015) Free radicals in biology and
medicine, 5th edn. Oxford University Press, USA
Seth K, Garg SK, Kumar R, Purohit P, Meena VS, Goyal R, Banerjee
UC, Chakraborti AK (2014) 2-(2-Arylphenyl) benzoxazole as a
novel anti-inflammatory scaffold: synthesis and biological eva-
luation. ACS Med Chem Lett 5:512–516
Harder E, Damm W, Maple J, Wu C, Reboul M, Xiang JY, Wang L,
Lupyan D, Dahlgren MK, Knight JL (2015) OPLS3: a force field
providing broad coverage of drug-like small molecules and pro-
teins. J Chem Theory Comput 12:281–296
Hossain SU, Bhattacharya S (2007) Synthesis of O-prenylated and O-
geranylated derivatives of 5-benzylidene2, 4-thiazolidinediones
and evaluation of their free radical scavenging activity as well as
effect on some phase II antioxidant/detoxifying enzymes. Bioorg
Med Chem Lett 17:1149–1154
Ishida T, In Y, Inoue M, Tanaka C, Hamanaka N (1990) Conformation
of (Z)-3-carboxymethyl-[(2E)-2-methyl-3-phenylpropenylidene]
rhodanine (epalrestat), a potent aldose reductase inhibitor: X-ray
crystallographic, energy calculational, and nuclear magnetic
resonance studies. J Chem Soc Perkin Trans 2:1085–1091
Ligprep (2018) Schrödinger Release 2018-1. Schrödinger, LLC, New
York, NY
Maccari R, Del Corso A, Giglio M, Moschini R, Mura U, Ottanà R
(2011) In vitro evaluation of 5-arylidene-2-thioxo-4-thiazolidi-
nones active as aldose reductase inhibitors. Bioorg Med Chem
Lett 21:200–203
Shih MH, Ke FY (2004) Syntheses and evaluation of antioxidant
activity of sydnonyl substituted thiazolidinone and thiazoline
derivatives. Bioorg Med Chem 12:4633–4643
Singh N, Tripathi AC, Tewari A, Kumar SarafSK (2015) Ulcer-
ogenicity devoid novel non-steroidal anti-inflammatory agents
(NSAIDS): syntheses, computational studies, and activity of 5-
aryliden-2-imino-4-thiazolidinones. Med Chem Res 24:1927–
1941
Soare JR, Dinis TC, Cunha AP, Almeida L (1997) Antioxidant
activities of some extracts of Thymus zygis. Free Radic Res
26:469–478
Taranalli A, Bhat A, Srinivas S, Saravanan E (2008) anti-inflamma-
tory, analgesic and antipyretic activity of certain thiazolidinones.
Indian J Pharm Sci 70:159–164
Tominaga H, Kobayashi Y, Goto T, Kasemura K, Nomura M (2005)
DPPH radical-scavenging effect of several phenylpropanoid
compounds and their glycoside derivatives. Yakugaku Zasshi
125:371–375
Vicini P, Geronikaki A, Anastasia K, Incerti M, Zani F (2006)
Synthesis and antimicrobial activity of novel 2-thiazolylimino-5-
arylidene-4-thiazolidinones. Bioorg Med Chem 14:3859–3864
Vicini P, Geronikaki A, Incerti M, Zani F, Dearden J, Hewitt M (2008)
2-Heteroarylimino-5-benzylidene-4-thiazolidinones analogues of
2-thiazolylimino-5-benzylidene-4-thiazolidinones with anti-
microbial activity: Synthesis and structure–activity relationship.
Bioorg Med Chem 16:3714–3724
Maestro (2018) Schrödinger Release 2018-1. Schrödinger, LLC, New
York, NY
Mensor LL, Menezes FS, Leitão GG, Reis AS, Santos TCD, Coube
CS, Leitão SG (2001) Screening of Brazilian plant extracts for
antioxidant activity by the use of DPPH free radical method.
Phytother Res 15:127–130
Momose Y, Meguro K, Ikeda H, Hatanaka C, Oi S, Sohda T (1991)
Studies on antidiabetic agents. X. Synthesis and biological
activities of pioglitazone and related compounds. Chem Pharm
Bull 39:1440–1445
Winter CA, Risley EA, Nuss GW (1962) Carrageenin-induced edema
in hind paw of the rat as an assay for anti-inflammatory drugs.
Proc Soc Exp Biol Med 111:544–547