Design, synthesis and molecular modelling of novel 4-thiazolidinones of potential activity against Gram positive bacteria

Article abstract of DOI:10.1007/s00044-012-0115-x

A series of novel 4-thiazolidinones (2-21) incorporating 2-(2,4,5-trichlorophenoxy)propanamide was synthesised. Reaction of 2-(2,4,5-trichlorophenoxy)propanohydrazide (1) with the corresponding carbonyl compounds afforded 2-(2,4,5-trichlorophenoxy)propanehydrazide hydrazones (2-11) which upon reaction with thioglycolic acid revealed 4-thiazolidinone derivatives (12-21). Structure elucidation of the synthesised compounds was done based on analytical and spectral data. The newly synthesised compounds were evaluated for their antimicrobial activity. Compounds 13 and 17 showed the equipotent activity with MIC value 6.25 μg ml^-1 compared with chloramphenicol as reference drug. Docking studies of the promising compounds was done on MurB using Dock6.4 docking program to study their observed activity.

Full text of DOI:10.1007/s00044-012-0115-x

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-012-0115-x
ORIGINAL RESEARCH
Design, synthesis and molecular modelling of novel
4-thiazolidinones of potential activity against Gram positive
bacteria
Awwad A. Radwan
Received: 2 January 2012 / Accepted: 22 May 2012
Ó Springer Science+Business Media, LLC 2012
Abstract A series of novel 4-thiazolidinones (2–21)
incorporating 2-(2,4,5-trichlorophenoxy)propanamide was
synthesised. Reaction of 2-(2,4,5-trichlorophenoxy)propa-
nohydrazide (1) with the corresponding carbonyl compounds
afforded 2-(2,4,5-trichlorophenoxy)propanehydrazide hydra-
zones (2–11) which upon reaction with thioglycolic acid
revealed 4-thiazolidinone derivatives (12–21). Structure
elucidation of the synthesised compounds was done based
on analytical and spectral data. The newly synthesised
compounds were evaluated for their antimicrobial activity.
Compounds 13 and 17 showed the equipotent activity with
MIC value 6.25 lg ml-1 compared with chloramphenicol
as reference drug. Docking studies of the promising com-
pounds was done on MurB using Dock6.4 docking program
to study their observed activity.
including emerging infectious diseases and the increasing
number of multi-drug resistant microbial pathogens with
particular relevance for Gram positive bacteria (Dessen
et al., 2001; Muroi et al., 2004; Pfeltz and Wilkinson,
2004; Roberts, 2004; Tenover and McDonald, 2005).
These resistant microorganisms cause infectious diseases
which are considered as an important challenge to the
medical community and need for an effective therapy
has led to an increasing search for novel antimicrobial
agents (Chikhalia and Vashi, 2009). Microorganism
resistance to antimicrobials threatens the health of many
throughout the world, since both old and new infectious
diseases remain a formidable public health threat. One of
the most interesting areas of research is the search for
compounds that combat resistant bacteria. Thiazolidi-
nones were found to possess antibacterial activity (Fuloria
et al., 2009; Kumar et al., 2012; Mistry and Jauhari,
2012; Solankee et al., 2012). Naturally occurring mole-
cules containing thiazolidinone moiety showed important
antibiotic, immunosuppressive and antitumor activities
(Vagdevi et al., 2006; Badorc et al., 1997; Rzasa et al.,
1998; Zhong, 2011). Thiazolidinones also, possess a
wide spectrum of activities like antifungal (Karali et al.,
1998; Fahmy, 2001, Khan and Yusuf, 2009), anticon-
vulsant (Ergenc and Capan, 1994; Capan et al., 1996),
COX-1 inhibitors (Look et al., 1996), antituberculosis
(Bukowski et al., 1998; Ulusoy, 2002; Babaoglu et al.,
2003) and antihistaminic (Diurno et al., 1992) activity.
Thiazolidinones containing b-lactam ring inhibit the
biosynthesis of the peptidoglycan polymer essential for
cell wall of bacteria. MurB enzyme is a unique target for
antibacterial activity of thiazolidinone (Andres et al.,
2000a, b). Thiazolidinones I were reported to be potent
inhibitor of MurB (Andres et al., 2000a, b; Bronson
et al., 2003). This activity, coupled with the design
Keywords 4-Thiazolidinones ꢀ Hydrazide–hydrazones ꢀ
Synthesis ꢀ Dock ꢀ Antibacterial
Introduction
One of the challenging dilemma in the medical com-
munity is the treatment of infectious diseases in hospital-
based healthcare because of a combination of factors
The author’s address on leave is Assiut University, Assiut, Egypt.
A. A. Radwan (&)
Pharmaceutical Technology Center (PTC),
College of Pharmacy, King Saud University,
P.O. Box 2457, Riyadh 11451, Saudi Arabia
e-mail: dhna_2001@hotmail.com
A. A. Radwan
Department of Pharmaceutical Organic Chemistry,
Faculty of Pharmacy, Assiut University, Assiut 71527, Egypt
123

Med Chem Res
principles of the thiazolidinones, supports the postulate
that 4-thiazolidinones may be recognized as diphosphate
mimics by a biological selector (Andres et al., 2000a, b).
On the basis of crystal structure analysis of the MurB
enoylpyruvate–UDP-N-acetylglucosamine (EP–UNAG) com-
plex, it was found that the carboxylate of the substrate
interacts with residues Arg159 and Glu325 and could be
responsible for transition state stabilization whereas the
diphosphate moiety of the substrate interacts with resi-
dues Tyr190, Lys217, Asn233 and Glu288. Thus, tem-
plates were chosen that contained functional surrogates
of the diphosphate with side-chains oriented to occupy
space similar to the glucosamine and uridine moieties as
potential MurB inhibitors. The 4-thiazolidinones met
these criteria and a series of compounds were synthes-
ised (Andres et al., 2000a, b).
elemental methods of analyses and were consistent with the
proposed structures. All spectral data are in accordance
with the assumed structures.
The most differentiating stretching bands in IR spectra are
shown at the range of 1,624–1,600 cm-1 for the hydrazone
C=N group of compounds, 2–11, and at the range of 1,722–
1,692 cm-1 for the carbonyl functionality of the 4-thiazo-
lidinone moiety of compounds 12–21. Generally, all the
synthesised compounds 2–21 showed carboxamide group at
the range of 1,687–1,664 and 3,256–3,164 cm-1 for the
carbonyl and amide functionalities, respectively. Further-
more, aliphatic C–H stretching around 2,994–2,904 cm-1
and aromatic C–H stretching around 3,100–3,031 cm-1 are
also observed. 1H and 13C NMR signals of compounds
(2–21) showed a similar trend in the chemical shift of the
common part of the molecular backbone. 1H-NMR spectra of
compounds 2–7 indicated the presence of a singlet at d 8.1–
8.43 ppm which could be assigned to CH=N. Compound 8
showed a characteristic signal at d 2.25 and 2.31 ppm cor-
responding to methyl group of p-tolyl moiety and methyl
group of ethylidene moiety, respectively. Compound 9
showed a characteristic signal at d 2.31 ppm due to methyl
group of ethylidene moiety. Compounds 10 and 11 showed
characteristic signals at d 6.99–7.96 ppm due to isatin moi-
ety. 1H-NMR spectra of thiazolidinones 12–21 revealed the
disappearance of imino group and appearance of a signal at d
3.24–3.71 which could be assigned for the methylene C-5
protons of the thiazolidinone ring. In addition, compounds
12–17 showed a signal at d 5.77–6.07 due methine C-2
proton of the thiazolidinone ring.
O
OH
O
S
R
O
O
N
O
S
N
R
N
H
R1
R
Ar
I
II
In view of these findings and in continuation of our work on
the synthesis of antimicrobial agents of pharmaceutical interest
(Radwan and Hussein, 2006; Hyallah and Radwan, 2007;
Mostafa et al., 2008), the rational approach to lead discovery
has prompted a better insight in developing new thiazolidinone
derivatives, with general formula II, based on the structural
formula I to explore substitution effect, at 2- and 3-position of
the thiazolidinone ring, on the antimicrobial activity.
13C-NMR spectra of compounds hydrazone compounds
2–11 showed a characteristic signal at d 156.1–167.1 ppm
due to hydrazone C=N, while the thiazolidinone com-
pounds 12–21 showed characteristic signals at d 34.5–
41.66, 53.01–72.34 and 165.88–170.46 ppm due to the
thiazolidinones C-5, C-2 and C-4, respectively.
Results and discussion
Mass spectra and elemental analysis were found in
agreement with the suggested chemical structures of the
synthesised compounds.
Synthesis
The key intermediate compound 1 was prepared from
2-(2,4,5-trichlorophenoxy)propanoic acid by the ester for-
mation followed by hydrazinolysis. The target compounds,
2–11, were synthesised by the reaction of compound 1 with
the corresponding carbonyl compound.
Antimicrobial evaluations
Compounds (2–21) were evaluated for their in vitro
antimicrobial activity against Gram positive bacteria:
S. aureus (ATCC 25923), B. subtilis (ATCC 10400) and
Gram negative bacteria: E. coli (ATCC 25922), P. aeru-
ginosa (ATCC 27855), Shig. Sonnei (ATCC 11060) and
fungal strains: C. albicans (ATCC 10231). Antimicrobial
activity was assessed by serial twofold dilution technique
(Madhukar et al., 2009). Chloramphenicol was used as a
standard drug for antibacterial activity and miconazole
was used as a standard drug for antifungal activity.
Table 1 lists the MIC values of the tested compounds.
2-(2,4,5-Trichlorophenoxy)-N-(4-oxo-2-substitutedthia-
zolidin-3-yl)propanamide derivatives (12–21) were obtained
via reaction of the corresponding compounds 2–11 with
thioglycolic acid, Scheme 1. Figure 1 shows that the
hydrazone undergoes attack by sulphur nucleophile,
followed by intramolecular cyclization on elimination of
water (Bolognese et al., 2004). Structures of the synthes-
ised compounds were verified on the bases of spectral and
123

Med Chem Res
Scheme 1 Adopted synthetic
pathways of compounds 2–21.
2, 12 R=H, Ar=C6H4NO2-3; 3,
13 R=H, Ar=C4H3S-2; 4, 14
R=H, Ar=C4H2S–CH3–5; 5, 15
R=H, Ar=C4H2O–CH3–5; 6, 16
R=H, Ar=C5H4N-3; 7, 17 R=H,
Ar=C5H4N-4; 8, 18 R=CH3,
Ar=C6H4–CH3-4; 9, 19 R=CH3,
Ar=C6H4-Cl-4; 10, 20 R1=H;
11, 21 R1=CH:C–CH2
Cl
Cl
MeOH/ H2SO4
Reflux
Cl
O
OH
O
Cl
O
O
O
Cl
Cl
Cl
H2N
EtOH/N2H4,
Reflux 4 h
Cl
O
NH
Cl
1
O
EtOH, Reflux 2 h
O
R
O
Ar
O
N
R1
Cl
Cl
Cl
Ar
R1
N
O
R
Cl
O
HN N
O
N
O
NH
Cl
Cl
10,11
O
2-9
O
HS
O
HS
OH
OH
PhH, Reflux 15-18 h
PhH, Reflux 15-18 h
R
Ar
R1
N
S
Cl
Cl
HN N
Cl
O
S
O
O
O
Cl
Cl
O
HN
N
Cl
O
O
12-19
20,21
Antimycobacterium tuberculosis activity
The thiazolidinone derivatives (12–21) were found inac-
tive against fungi strains and Gram negative bacteria,
while they exhibited promising antibacterial activity
against Gram positive bacteria strains. Compounds 13 and
17 were found equipotent to chloramphenicol as growth
inhibitors of the tested Gram positive bacteria. Com-
pounds 12, 14–16, 18 and 19 were found either equipotent
or slightly less potent than chloramphenicol as growth
inhibitors of the tested Gram positive bacteria, while
compounds 20 and 21 showed a weak activity. On the
other hand, compounds (2-11) did not show any activity
against all the species tested.
Primary screening of compounds (2–21) for their in vitro
antituberculosis against M. tuberculosis H37Rv using
microdilution assay, the Microplate Alamar Blue Assay
(MABA) (Collins and Franzblau, 1997). None of the syn-
thesized compounds exhibited antimycobacterial activity.
Docking procedure
In order to investigate the possible interactions between our
newly synthesised compounds and the active site of the
123

Med Chem Res
O
HS
OH
S
N
R
HN
R
O
OH
-H2O
S
S
R
N
R
N
O
O
H2O
Fig. 1 Mechanism of formation of 1,3-thiazolidin-4-ones from imine
MurB enzyme, a docking process were undertaken using
Dock6.4 (Lang et al., 2009). In the docking procedure, the
coordinates of UDP-N-acetylmuramate dehydrogenase
(E. coli MurB) enzyme X-ray structure, complexed with its
co-crystallised ligand naphthyl tetronic acid inhibitor,
(2Q85) was taken from the Protein Data Bank (Mansour
Fig. 2 Naphthyl tetronic acid from 2Q85 (X-ray white, docked cyan)
oriented in UDP-N-acetylmuramate dehydrogenase (MurB) binding site
(hydrogen bonds are displayed in orange cylinder) (Color figure online)
The docking poses belonging to our newly synthesised
anti-Gram positive bacteria active compounds (Figs. 3, 4)
suggested that hydrogen bonding between the carbonyl
oxygen of the thiazolidinone ring and the amino group of
Asn 233 stabilized the aromatic ring (4-pyridinyl) group
over the thiazolidinone ring system in parallel orientation
between its pi system and the Ala 264, Ala 265 and Leu
290 with hydrophobic interaction between hydrophobic
side chains of these amino acids and the electronic system
of the pi system. However, the trichlorophenyl moiety is
generally oriented in the hydrophobic pocket surrounded
by the side chains of Ala 124, Arg 214, Lys 217 and
Leu 218. The propionamide moiety is stabilized by the
˚
et al., 2007). The RMSD value difference of 0.53 A of the
pose from the non-restricted redocking of the naphthyl
tetronic acid inhibitor, MurB-bound X-ray ligand, structure
itself also confirmed the approach (Fig. 2). The binding site
includes hydrophobic pocket delineated by the side chains
of Lys 217, Leu 218, Ala 265, Glu 288, Leu 290, and the
binding site which is enriched with hydrogen bond donor
groups represented by Arg 159, Arg 214, Asn 233, Glu 325
and Tyr 190 that surrounds the functional groups of the
oxalane ring of naphthyl tetronic acid inhibitor, X-ray
ligand (Fig. 2).
Table 1 Minimum inhibitory concentration in lg ml-1 of compounds 12–21 against selected microbial strains
Compd.
no.
Staphylococcus
aureus
Bacillus
subtilis
Escherichia
coli
Salmonella
typhimurium
Shigella
sonnei
Pseudomonous
aeruginosa
Candida
albicans
12
12.5
6.25
12.5
12.5
6.25
6.25
12.5
12.5
25
12.5
6.25
12.5
12.5
12.5
6.25
6.25
12.5
50
–
–
–
–
–
–
–
–
13
–
–
14
–
–
–
–
–
15
–
–
–
–
–
16
–
–
–
–
–
17
–
–
–
–
–
18
–
–
–
–
–
19
–
–
–
–
–
20
–
–
–
–
–
21
50
50
–
–
–
–
–
Chloramph
Miconazole
6.25
–
6.25
–
12.5
–
25
–
25
–
–
–
3.12
3.12
123

Med Chem Res
Fig. 3 Compound 17 (coloured white) docked in MurB binding site
(hydrogen bonds are displayed in orange cylinder) (Color figure
online)
Fig. 5 Compound 21 (coloured cyan) docked in MurB binding site
(hydrogen bond is displayed in orange cylinder) (Color figure online)
hydrophobic interaction between the side chain of Leu 290
and the methyl group of propionamide moiety and, in some
cases, hydrogen boding between the amide oxygen atom
and the hydroxyl group of Tyr 190. The docking poses
belonging to our newly synthesised compounds with thia-
zolidinone ring in spiro structure with heterocyclic ring
(anti-Gram positive bacteria weak active compounds 20
and 21, Fig. 5) failed to be oriented inside the proposed
binding pocket.
Experimental
Synthesis
Melting points were determined on Barnstead 9001 Elec-
trothermal melting point apparatus using open capillary
tubes and are uncorrected. IR spectra were obtained, as KBr
discs, on a Perkin Elmer FT-IR spectrophotometer at the
Research Center, College of Pharmacy, King Saud Uni-
versity, Saudi Arabia. The data are given in mmax (cm-1).
1H and 13C NMR spectra were recorded in either DMSO-d6
or CDCl3 on a Bruker NMR spectrophotometer operating at
Although the generated docking poses illustrated a
parallelism between MIC values against the tested Gram
positive bacteria strains and compound interactions with
the surrounding environment regarding side chain changes
in general, more new analogues are suggested to be syn-
thesised with its in vitro evaluation against MurB enzyme
for further molecular modelling studies would be the best
option for verification.
500 MHz for H and 125.76 MHz for 13C; the chemical
1
shifts are expressed in d (ppm) downfield from tetrameth-
ylsilane (TMS) used as internal standard. Mass spectra were
taken on a Varian 320-MS spectrometer at the Research
Center, College of Pharmacy, King Saud University, Saudi
Arabia. Mass spectral data were given as m/z (intensity %).
Elemental analysis was performed on a Perkin Elmer CHN
analyzer, model no. 2400. Monitoring of reactions and
checking of purity of the final products were carried out by
thin layer chromatography (TLC) using silica gel precoated
aluminium sheets (60 F254, Merck), The developing sol-
vent system was chloroform/methanol (8:2) and the spots
were detected with ultraviolet light (UV) at 365 and
254 nm. (RS)-2-(3,4,5-tri-chlorophenoxypropionic acid,
silvex, was obtained from Acros (Geel, Belgium), alde-
hydes, acetophenones and thioglycolic acid were purchased
from Sigma-Aldrich Company (St. Louis, MO, USA).
Antimicrobial activity was done at the research centre,
college of Pharmacy, King Saud University, Saudi Arabia.
Fig. 4 Binding site surface with docked, compound 17 (coloured
magenta, hydrogen bond coloured orange) (Color figure online)
123

Med Chem Res
2-(2,4,5-Trichlorophenoxy)propanehydrazide (1)
2-(2,4,5-Trichlorophenoxy)-N0-((thiophen-2-
yl)methylene)propanehydrazide (3)
A solution of 2-(2,4,5-Trichlorophenoxy)propanoic acid
(10 mmol, 2.69 g) and ethanol (20 ml) containing few
drops of sulphuric acid was refluxed for 4 h. The reaction
mixture was cooled and excess alcohol was removed under
reduced pressure. The remaining residue was poured onto a
5 % aqueous sodium bicarbonate solution (25 ml). Then
the aqueous layer was extracted using diethyl ether. The
organic layer extract was dried over anhydrous magnesium
sulphate followed by evaporation of the ether solvent under
reduced pressure. The obtained oily product of the crude
ester and an excess of hydrazine hydrate (30 mmol) in
ethanol (20 ml) was refluxed for 3 h and cooled. The solid
was separated by filtration and recrystallised from ethanol
to afford 2-(2,4,5-trichlorophenoxy)propanehydrazide 1 as
colourless fine needles. Yield 83 %; m.p. 210-211 °C; IR,
(KBr, cm-1): 3318, 3264 (NH, NH2), 3,031(CH-arom.),
2985 (CH-aliph.), 1662 (C=O). 1H-NMR (DMSO-d6, d,
ppm): 1.45 [d, 3H, CH3], 4.25 [s, 2H, NH2, D2O
exchangeable], 4.72 [q, 1H, O–CH–CO], 7.15 [s, 1H, tri-
chlorophenyl-H6], 7.61 [s, 1H, trichlorophenyl-H3], 9.18
[s, 1H, CONH–, D2O exchangeable]. Anal. Calcd. for
C9H9Cl3N2O2: C, 38.12; H, 3.20; N, 9.88. Found: C, 38.35;
H, 3.31; N, 9.72.
Yield 78 %; m.p. 210–211 °C; IR (KBr, cm-1): 3168 (NH),
3084 (CH-arom.), 2953 (CH-aliph.), 1672 (C=O), 1612
1
(C=N). H-NMR (DMSO-d6, d, ppm): 1.56 [d, 3H, CH3],
5.00 [q, 1H, –O–CH–CO], 7.15 [t, 1H, Ar–H4], 7.31 [s, 1H,
trichlorophenyl-H6], 7.46 [d, 1H, Ar–H5], 7.65 [d, 1H,
Ar–H3], 7.84 [s, 1H, trichlorophenyl-H3], 8.22 [s, 1H,
CH=N], 11.60 [s, 1H, CONH, D2O exchangeable]. 13C-
NMR (CDCl3, d, ppm): 17.1 (CH3), 71.8 (O–C–), 115.6,
121.5, 123.0, 127.8, 128.7, 130.2, 138.4, 139.5, 143.5, 152.3
(aromatic carbons), 165.9 (C=N), 170.0 (C=O). MS (m/z):
377 [M??2] (3.3), 375 [M?] (3.7), 41 (100). Anal. Calcd.
for C14H11Cl3N2O2S: C, 44.52; H, 2.94; N, 7.42; S, 8.49.
Found: C, 44.79; H, 3.13; N, 7.58; S, 8.65.
2-(2,4,5-Trichlorophenoxy)-N0-((5-methylthiophen-2-
yl)methylene)propanehydrazide (4)
Yield 75 % m.p. 188–189 °C; IR (KBr, cm-1): 3188 (NH),
3094 (CH-arom.), 2947 (CH-aliph.), 1662 (C=O), 1604
(C=N). 1H-NMR (CDCl3, d, ppm): 1.55 [d, 3H, CH3], 2.46
[s, 3H, Ar–CH3], 4.99 [q, 1H, –O–CH–CO], 6.81 [d, 1H,
Ar–H4], 7.26 [d, 1H, Ar–H3], 7.31 [s, 1H, trichlorophenyl-
H6], 7.84 [s, 1H, trichlorophenyl-H3], 8.10 [s, 1H, CH=N],
11.53 [s, 1H, CONH, D2O exchangeable]. 13C-NMR
(CDCl3, d, ppm): 15.2 (Ar–CH3), 17.0 (CH3), 71.9 (O–CH–),
115.6, 121.6, 123.0, 126.2, 130.2, 131.1, 136.2, 139.5,
142.6, 152.3 (aromatic carbons), 165.7 (C=N), 169.8 (C=O).
MS (m/z): 391 [M??2] (6.8), 389 [M?] (7.2), 105 (100).
Anal. Calcd. for C15H13Cl3N2O2S: C, 45.99; H, 3.35;
N, 7.15; S, 8.19. Found: C, 45.72; H, 3.51; N, 7.01;
S, 7.92.
2-(2,4,5-Trichlorophenoxy)propanehydrazide hydrazones
(2–11)
A mixture of 1 (10 mmol, 2.83 g) and a corresponding
carbonyl compound (20 mmol) in ethanol (50 ml) con-
taining a catalytic amount of glacial acetic acid (1 ml) was
refluxed for 2 h. The mixture was cooled; the solid was
separated by filtration and recrystallized from ethanol to
give the corresponding hydrazide–hydrazones 2–11.
2-(2,4,5-Trichlorophenoxy)-N0-(3-
nitrobenzylidene)propanehydrazide (2)
2-(2,4,5-Trichlorophenoxy)-N0-((5-methylfuran-2-
yl)methylene)propanehydrazide (5)
Yield 95 %; m.p. 230–231 °C; IR (KBr, cm-1): 3174
(NH), 3092 (CH-arom.), 2938 (CH-aliph.), 1666 (C=O),
Yield 73 %; m.p. 207–208 °C; IR, (KBr, cm-1): 3216
(NH), 3053(CH-arom.), 2971 (CH-aliph.), 1667 (C=O),
1624 (C=N). 1H-NMR (CDCl3, d, ppm): 1.73 [d, 3H,
CH3], 2.36 [s, 3H, Ar–CH3], 4.84 [q, 1H, –O–CH–CO],
6.14 [d, 1H, Ar–H4], 6.7 [d, 1H, Ar–H3], 7.13 [s, 1H,
trichlorophenyl-H6], 7.52 [s, 1H, trichlorophenyl-H3],
8.20 [s, 1H, CH=N], 11.27 [s, 1H, CONH, D2O
exchangeable]. 13C-NMR (CDCl3, d, ppm): 15.3 (Ar–
CH3), 17.9 (CH3), 58.4 (O–CH–), 108.5, 116.9, 117.9,
122.7, 126.4, 131.0, 131.9, 139.8, 147.0, 151.1 (aromatic
carbons), 156.1 (CH=N), 167.6 (C=O). MS (m/z): 376
[M??2] (4.2), 374 [M?] (3.9), 52 (100). Anal. Calcd. for
C15H13Cl3N2O3: C, 47.96; H, 3.49; N, 7.46. Found: C,
48.15; H, 3.63; N, 7.58.
1
1609 (C=N). H-NMR (DMSO-d6, d, ppm): 1.6 [d, 3H,
CH3], 5.07 [q, 1H, –O–CH–CO], 7.24 [s, 1H, trichlor-
ophenyl-H6], 7.72 [t, 1H, Ar–H5], 7.85 [s, 1H, trichlor-
ophenyl-H3], 8.12 [d, 1H, Ar–H6], 8.25, [s, 1H, CH=N],
8.43 [d, 1H, Ar–H4], 8.52 [s, 1H, Ar–H2], 11.92 [s, 1H,
CONH, D2O exchangeable]. 13C-NMR (DMSO-d6, d,
ppm): 17.2 (CH3), 72.1 (O–C–), 152.29, 148.1, 146.0,
142.2, 135.6, 132.8, 130.8, 130.1, 124.2, 123.1, 121.1,
115.7 (aromatic carbons), 166.49 (CH=N), 170.7 (C=O).
MS (m/z): 417 [M??2] (8.5), 415 [M?] (8.7), 41 (100).
Anal. Calcd. for C16H12Cl3N3O4: C, 46.12; H, 2.90; N,
10.09. Found: C, 46.37; H, 3.11; N, 10.23.
123

Med Chem Res
2-(2,4,5-Trichlorophenoxy)-N0-((pyridin-3-
yl)methylene)propanehydrazide (6)
2-(2,4,5-Trichlorophenoxy)-N0-(1-(4-
chlorophenyl)ethylidene)propanehydrazide (9)
Yield 82 %; m.p. 192–193 °C; IR, (KBr, cm-1): 3204
(NH), 3062 (CH-arom.), 2994 (CH-aliph.), 1670 (C=O),
1609 (C=N). 1H-NMR (CDCl3, d, ppm): 1.75 [d, 3H, CH3],
4.9 [q, 1H, –O–CH–CO], 7.10 [s, 1H, trichlorophenyl-H6],
7.36 [t, 1H, Ar–H5], 7.92 [s, 1H, trichlorophenyl-H3], 8.20
[d, 1H, Ar–H6], 8.28 [s, 1H, CH=N], 8.65, [d, 1H, Ar–H4],
8.82 [d, 1H, Ar–H2], 10.62 [s, 1H, CONH, D2O
exchangeable]. 13C-NMR (CDCl3, d, ppm): 17.8 (CH3),
72.7 (O–CH–),116.2, 122.8, 126.6, 129.2, 131.3, 133.7,
142.8, 146.5, 148.9, 151.1, 152.6 (aromatic carbons), 166.9
(CH=N), 172.5 (C=O). MS (m/z): 373 [M??2] (6.7), 371
[M?] (6.1), 148 (100). Anal. Calcd. for C15H12Cl3N3O2: C,
48.35; H, 3.25; N, 11.28. Found: C, 48.20; H, 3.39; N,
11.01.
Yield 95 % m.p. 198–199 °C; IR, (KBr, cm-1): 3174
(NH), 3033 (CH-arom.), 2986 (CH-aliph.), 1674 (C=O),
1613 (C=N).1H-NMR (CDCl3, d, ppm): 1.67 [d, 3H, CH3],
2.31 [s, 3H, CH3–C=], 4.98 [q, 1H, –O–CH–CO], 7.11 [s,
1H, trichlorophenyl-H6], 7.28 [s, 1H, trichlorophenyl-H3],
7.39 [d, 2H, Ar–H3, Ar–H5], 7.81 [d, 2H, Ar–H2, Ar–H6],
9.63 [s, 1H, CONH, D2O exchangeable]. 13C-NMR
(CDCl3, d, ppm): 13.2 (CH3), 18.2 (CH3), 73.4 (O–CH–),
116.2, 122.4, 127.4, 128.6, 129.7, 131.1, 132.0, 135.8,
136.1, 152.6 (aromatic carbons), 166.1 (C=N), 171.8
(C=O). MS (m/z): 420 [M??2] (10.7), 418 [M?] (9.1).
Anal. Calcd. for C17H14Cl4N2O2: C, 48.60; H, 3.36; N,
6.67. Found: C, 48.79; H, 3.18; N, 6.51.
2-(2,4,5-Trichlorophenoxy)-N0-(2-oxoindolin-3-
ylidene)propanehydrazide (10)
2-(2,4,5-Trichlorophenoxy)-N0-((pyridin-4-
yl)methylene)propanehydrazide (7)
Yield 91 %; m.p. 208–209 °C; IR, (KBr, cm-1): 3183
(NH), 3073 (CH-arom.), 2934 (CH-aliph.), 1709 (C=O),
1679 (C=O), 1622 (C=N). 1H-NMR (CDCl3, d, ppm): 1.78
[d, 3H, CH3], 4.97 [q, 1H, –O–CH–CO], 6.99 [d, 1H,
isatin-H4], 7.1 [s, 1H, trichlorophenyl-H6], 7.14 [t, 1H,
isatin-H5], 7.37 [t, 1H, isatin-H6], 7.54 [s, 1H, trichlor-
ophenyl-H3], 7.82 [d, 1H, isatin-H7], 7.96 [s, 1H, isatin-
NH, D2O exchangeable], 8.1 [s, 1H, CONH, D2O
exchangeable]. 13C-NMR (CDCl3, d, ppm): 18.52 (CH3),
58.49 O–CH–), 110.8, 116.9, 122.6, 123.4, 123.6, 126.3,
131.4, 132.2, 138.8, 141.0, 151.3 (aromatic carbons), 162.3
(C=O), 168.6 (C=O). Mass m/z [%]: 412 [M??2] (5.3),
410 [M?] (5.1), 43 (100). Anal. Calcd. for C17H12Cl3N3O3:
C, 49.48; H, 2.93; N, 10.18. Found: C, 49.21; H, 2.80; N,
10.02.
Yield 85 % m.p. 163–164 °C; IR, (KBr, cm-1): 3286
(NH), 3100 (CH-arom.), 2940 (CH-aliph.), 1687 (C=O),
1600 (C=N). 1H-NMR (CDCl3, d, ppm): 1.75 [d, 3H,
CH3], 4.91 [q, 1H, –O–CH–CO], 7.10 [s, 1H, trichlor-
ophenyl-H6], 7.63 [d, 2H, Ar–H2, Ar–H6], 7.73 [s, 1H,
trichlorophenyl-H3], 8.25 [s, 1H, CH=N], 8.68 [d, 2H, Ar–
H3, Ar–H5], 10.7 [s, 1H, CONH, D2O exchangeable]. 13C-
NMR (DMSO-d6, d, ppm): 17.8 (CH3), 72.8 (O–CH–),
116.3, 121.0, 126.7, 131.2, 140.8, 143.1, 146.9, 150.0,
152.5 (aromatic carbons), 167.1 (CH=N), 172.7 (C=O). MS
(m/z): 373 [M??2] (7.3), 371 [M?] (6.8), 43 (100). Anal.
Calcd. for C15H12Cl3N3O2: C, 48.35; H, 3.25; N, 11.28.
Found: C, 48.02; H, 3.39; N, 11.15.
2-(2,4,5-Trichlorophenoxy)-N0-(2-oxo-1-(prop-2-
ynyl)indolin-3-ylidene)propanehydrazide (11)
2-(2,4,5-Trichlorophenoxy)-N0-(1-p-
tolylethylidene)propanehydrazide (8)
Yield 85 % m.p. 182–183 °C; IR, (KBr, cm-1): 3209
(NH), 3097 (CH-arom.), 2938 (CH-aliph.), 2237 (C:C),
1713 (C=O), 1677 (C=O) 1614 (C=N). H-NMR (CDCl3,
Yield 93 %; m.p. 196–197 °C; IR, (KBr, cm-1): 3201
(NH), 3037 (CH-arom.), 2934 (CH-aliph.), 1664 (C=O),
1610 (C=N). 1H-NMR (CDCl3, d, ppm): 1.77 [d, 3H, CH3],
2.25 [s, 3H, p-tolyl-CH3], 2.31 [s, 3H, ethylidene-CH3],
4.98 [q, 1H, –O–CH–CO], 7.11 [s, 1H, trichlorophenyl-
H6], 7.22 [d, 2H, Ar–H3, Ar–H5], 7.55 [s, 1H, trichlor-
ophenyl-H3], 7.76 [d, 2H, Ar–H2, Ar–H6], 9.58 [s, 1H,
CONH, D2O exchangeable]. 13C-NMR (CDCl3, d, ppm):
12.8 (Ar–CH3), 17.8 (CH3), 21.3 (CH3), 73.0 (O–CH–),
116.2, 122.4, 126.1, 129.2, 130.3, 131.9, 134.5, 140.0,
150.8, 154.0 (aromatic carbons), 166.0 (C=N), 172.0
(C=O). MS (m/z): 398 [M??2] (3.2), 400 [M?] (3.5). Anal.
Calcd. for C18H17Cl3N2O2: C, 54.09; H, 4.29; N, 7.01.
Found: C, 53.82; H, 4.03; N, 7.22.
1
d, ppm): 1.65 [d, 3H, CH3], 2.18 [s, 1H, :CH], 4.49 [s,
2H, :C–CH2–N], 4.94 [q, 1H, –O–CH–CO], 7.0 [d, 1H,
isatin-H4], 7.1 [s, 1H, trichlorophenyl-H6], 7.17 [t, 1H,
isatin-H5], 7.44 [t, 1H, isatin-H6], 7.54 [s, 1H, trichlor-
ophenyl-H3], 7.84 [d, 1H, isatin-H7], 8.0 [s, 1H, CONH,
D2O exchangeable]. 13C-NMR (CDCl3, d, ppm): 18.5
(CH3), 29.4 (propynyl-C1), 63.4 (propynyl-C3), 71.3 (O–
CH–), 86.8 (propynyl-C2), 110.2, 117.5, 119.4, 120.9,
123.7, 126.5, 131.2, 131.9, 138.8, 142.5, 151.4 (aromatic
carbons), 160.2 (C=O), 168.6 (C=O). Mass m/z [ %]: 451
[M??2] (15.0), 449 [M?] (13.5), 61 (100.0). Anal. Calcd.
123

Med Chem Res
for C20H14Cl3N3O3: C, 53.30; H, 3.13; N, 9.32. Found: C,
53.58; H, 3.01; N, 9.51.
C16H13Cl3N2O3S2: C, 42.54; H, 2.90; N, 6.20. Found: C,
42.15; H, 2.78; N, 6.46.
2-(2,4,5-Trichlorophenoxy)-N-(4-oxo-2-
substitutedthiazolidin-3-yl)propanamide (12–21)
2-(2,4,5-Trichlorophenoxy)-N-(2-(5-methylthiophen-2-yl)-
4-oxothiazolidin-3-yl)propanamide (14)
To a well-stirred suspension of the appropriate hydrazone
derivatives (2–11), (10 mmol) in dry benzene (50 ml),
mercaptoacetic acid (4.2 ml, 60 mmol) in dry benzene
(10 ml) was added. The reaction mixture was refluxed for
15-18 h and the solvent was evaporated under reduced
pressure. The residue was triturated with boiling water
(100 ml), left overnight, filtered off, washed with water,
dried and crystallised from the proper solvent affording the
title compounds (12–21).
Yield 78 % m.p. 135–136 °C; IR, (KBr, cm-1): 3175
(NH), 3062 (CH-arom.), 2925 (CH-aliph.), 1722 (C=O
thiazolidinone), 1685 (C=O amide).1H-NMR (DMSO-d6,
d, ppm): 1.47 [d, 3H, CH3], 2.25 [s, 3H, Ar–CH3], 3.49 [s,
2H, thiazolidinone-H3], 4.82 [q, 1H, –O–CH–CO], 5.96 [s,
1H, thiazolidinone-H5], 6.65 [d, 1H, Ar–H4], 6.90 [d, 1H,
Ar–H3], 7.21 [s, 1H, trichlorophenyl-H6], 7.83 [s, 1H,
trichlorophenyl-H3], 12.67 [s, 1H, CONH, D2O exchange-
able]. 13C-NMR (DMSO-d6, d, ppm): 15.25 (Ar–CH3),
18.75 (CH3), 40.54 (thiazolidinone N–CH-S), 57.27 (thia-
zolidinone CH2), 73.24 (O–CH–), 116.25, 121.59, 123.60,
125.04, 126.60, 129.04, 130.2, 130.6, 141.8, 152.1 (aro-
matic carbons), 170.46 (thiazolidinone C=O), 172.04
(C=O). Mass m/z [%]: 465 [M??2] (2.4), 463 [M?] (2.2),
118 (100.0). Anal. Calcd. for C17H15Cl3N2O3S2: C, 43.83;
H, 3.25; N, 6.01. Found: C, 43.61; H, 3.40; N, 6.25.
2-(2,4,5-Trichlorophenoxy)-N-(2-(3-nitrophenyl)-4-
oxothiazolidin-3-yl)propanamide (12)
Yield 75 % m.p. 182–183 °C; IR (KBr, cm-1): 3173 (NH),
3085 (CH-arom.), 2985 (CH-aliph.), 1728 (C=O thiazo-
lidinone), 1669 (C=O amide). 1H-NMR (DMSO-d6, d,
ppm): 1.6 [d, 3H, CH3], 3.34 [s, 2H, thiazolidinone-H3],
5.08 [q, 1H, –O–CH–CO], 5.85 [s, 1H, thiazolidinone-H5],
7.26 [s, 1H, trichlorophenyl-H6], 7.34 [s, 1H, trichlor-
ophenyl-H3], 7.74 [dd, 1H, Ar–H5], 7.82 [s, 1H, Ar–H6],
8.12 [d, 1H, Ar–H4], 8.16 [s, 1H, Ar–H2], 11.9 [s, 1H,
CONH, D2O exchangeable]. 13C-NMR (DMSO-d6, d,
ppm): 18.09 (CH3), 41.66 (thiazolidinone N–CH–S), 66.32
(thiazolidinone CH2), 74.46 (O–CH–), 115.85, 121.10,
123.10, 124.44, 130.1, 130.88, 133.34, 135.78, 142.30,
146.0, 148.20, 152.70 (aromatic carbons), 166.48 (thiazo-
lidinone C=O), 170.78 (C=O). Anal. Calcd. for C18H14
Cl3N3O5S: C, 44.05; H, 2.88; N, 8.56. Found: C, 44.31; H,
3.02; N, 8.35.
2-(2,4,5-Trichlorophenoxy)-N-(2-(5-methylfuran-2-yl)-4-
oxothiazolidin-3-yl)propanamide (15)
Yield 73 %; m.p. 150–151 °C; IR, (KBr, cm-1): 3213
(NH), 3100 (CH-arom.), 2907 (CH-aliph.), 1708 (C=O
thiazolidinone), 1668 (C=O amide).1H-NMR (DMSO-d6,
d, ppm): 1.49 (d, 3H, CH3), 2.26 (s, 3H, Ar–CH3), 3.48
(s, 2H, thiazolidinone-H3), 4.92 (q, 1H, –O–CH–CO),
5.77 (s, 1H, thiazolidinone-H5), 6.03 (d, 1H, Ar–H4),
6.40 (d, 1H, Ar–H3), 7.30 (s, 1H, trichlorophenyl-H6),
7.82 (s, 1H, trichlorophenyl-H3), 11.50 (s, 1H, CONH).
13C-NMR (DMSO-d6, d, ppm): 13.43 (Ar–CH3), 18.65
(CH3), 38.99 (thiazolidinone N–CH-S), 53.01 (thiazolid-
inone CH2), 74.58 (O–CH–), 108.58, 116.48, 122.08,
128.28, 130.86, 134.66, 137.94, 147.47, 152.31, 154.82
(aromatic carbons), 165.88 (thiazolidinone C=O), 170.11
(C=O). Mass m/z [%]: 449 [M??2] (4.2), 447 [M?]
(4.4), 62 (100.0). Anal. Calcd. for C17H15Cl3N2O4S: C,
45.40; H, 3.36; N, 6.23. Found: C, 45.18; H, 3.11; N,
6.52.
2-(2,4,5-Trichlorophenoxy)-N-(4-oxo-2-(thiophen-2-
yl)thiazolidin-3-yl)propanamide (13)
Yield 78 % m.p. 123–124 °C; IR, (KBr, cm-1): 3164
(NH), 3046 (CH-arom.), 2982 (CH-aliph.), 1721 (C=O
1
thiazolidinone), 1677 (C=O amide). H-NMR (DMSO-d6,
d, ppm): 1.43 [d, 3H, CH3], 3.24 [s, 2H, thiazolidinone-
H3], 4.87 [q, 1H, –O–CH–CO], 6.07 [s, 1H, thiazolidinone-
H5], 6.98–7.00 [m, 2H, Ar–H3 and Ar–H4], 7.21 [d, 1H,
Ar–H5], 7.31 [s, 1H, trichlorophenyl-H6], 7.83 [s, 1H,
trichlorophenyl-H3], 12.60 [s, 1H, CONH, D2O exchange-
able]. 13C-NMR (DMSO-d6, d, ppm): 18.16 (CH3), 40.55
(thiazolidinone N–CH–S), 57.29 (thiazolidinone CH2),
73.79 (O–CH–),116.3, 121.8, 123.7, 126.7, 128.4, 128.9,
130.2, 130.6, 141.4, 152.2 (aromatic carbons), 168.02
(thiazolidinone C=O), 172.04 (C=O). Mass m/z [%]: 451
[M??2] (4.5), 449 [M?] (4.3), 45 (100.0). Anal. Calcd. for
2-(2,4,5-Trichlorophenoxy)-N-(4-oxo-2-(pyridin-3-
yl)thiazolidin-3-yl)propanamide (16)
Yield 73 % m.p. 212–213 °C; IR, (KBr, cm-1): 3190
(NH), 3061 (CH-arom.), 2989 (CH-aliph.), 1704 (C=O
thiazolidinone), 1680 (C=O amide).1H-NMR (DMSO-d6,
d, ppm): 1.40 [d, 3H, CH3], 3.63 [s, 2H, thiazolidinone-
H3], 4.84 [q, 1H, –O–CH–CO], 5.83 [s, 1H, thiazolidinone-
H5], 7.14 [s, 1H, trichlorophenyl-H6], 7.41 [dd, 1H, Ar–H5],
123

Med Chem Res
2-(2,4,5-Trichlorophenoxy)-N-(2-(4-chlorophenyl)-2-
methyl-4-oxothiazolidin-3-yl)propanamide (19)
7.79 [s, 1H, trichlorophenyl-H3], 7.89 [d, 1H, Ar–H4], 8.55
[d, 1H, Ar–H6], 8.62 [s, 1H, Ar–H2], 10.64 [s, 1H, CONH,
D2O exchangeable]. 13C-NMR (DMSO-d6, d, ppm): 18.55
(CH3), 29.12 (thiazolidinone N–CH–S), 59.49 (thiazolidi-
none CH2), 73.66 (O–CH–), 116.42, 121.83, 123.5, 123.71,
130.27, 130.69, 133.73, 135.67, 149.06, 150.17, 151.98
(aromatic carbons), 168.50 (thiazolidinone C=O), 169.01
(C=O). Mass m/z [%]: 446 [M??2] (5.2), 444 [M?] (5.0),
176 (100). Anal. Calcd. for C17H14Cl3N3O3S: C, 45.71; H,
3.16; N, 9.41. Found: C, 46.04; H, 3.03; N, 9.18.
Yield 84 % m.p. 195–196 °C; IR, (KBr, cm-1): 3174
(NH), 3034 (CH-arom.), 2985 (CH-aliph.), 1693 (C=O
1
thiazolidinone), 1668 (C=O amide). H-NMR (DMSO-d6,
d, ppm): 1.59 [d, 3H, CH3], 2.28 [s, 3H, thiazolidinone-5-
CH3], 3.34 [s, 2H, thiazolidinone-H3], 5.25 [q, 1H, –O–
CH–CO], 7.17 [s, 1H, trichlorophenyl-H6], 7.44 [d, 2H,
Ar–H3, Ar–H5], 7.49 [d, 2H, Ar–H2 and Ar–H6], 7.77 [s,
1H, trichlorophenyl-H3], 10.99 [s, 1H, CONH, D2O
exchangeable]. 13C-NMR (DMSO-d6, d, ppm): 17.40
(CH3), 18.32 (CH3), 34.50 (thiazolidinone N–CH–S), 66.31
(thiazolidinone CH2), 73.62 (O–CH–), 115.70, 122.95,
127.90, 128.28, 130.04, 130.73, 133.97, 136.55, 148.19,
152.50 (aromatic carbons), 166.5 (thiazolidinone C=O),
171.41 (C=O). Mass m/z [%]: 493 [M??2] (6.9), 491 [M?]
(7.8), 47 (100). Anal. Calcd. for C19H16Cl4N2O3S: C,
46.17; H, 3.26; N, 5.67. Found: C, 46.42; H, 3.04; N, 5.46.
2-(2,4,5-Trichlorophenoxy)-N-(4-oxo-2-(pyridin-4-
yl)thiazolidin-3-yl)propanamide (17)
Yield 73 % m.p. 155–156 °C; IR, (KBr, cm-1): 3191
(NH), 3100 (CH-arom.), 2960 (CH-aliph.), 1705 (C=O
1
thiazolidinone), 1665 (C=O amide). H-NMR (DMSO-d6,
d, ppm): 1.50 (d, 3H, CH3), 3.51 (s, 2H, thiazolidinone-
H3), 5.10 (q, 1H, –O–CH–CO), 5.85 (s, 1H, thiazolidinone-
H5), 7.25 (s, 1H, trichlorophenyl-H6), 7.62 (d, 2H, Ar–H3,
Ar–H5), 7.80 (s, 1H, trichlorophenyl-H3), 8.64 (d, 2H, Ar–
H2 and Ar–H6), 12.07 (s, 1H, CONH, D2O exchangeable).
13C-NMR (DMSO-d6, d, ppm): 18.19 (CH3), 29.12 (thia-
zolidinone N–CH–S), 72.09 (thiazolidinone CH2), 74.33
(O–CH–), 115.83, 121.02, 123.64, 130.78, 140.95, 142.01,
146.04, 150.11, 152.69 (aromatic carbons), 166.61 (thia-
zolidinone C=O), 170.95 (C=O). Mass m/z [%]: 446
[M??2] (6.9), 444 [M?] (6.4), 197 (100). Anal. Calcd. for
C17H14Cl3N3O3S: C, 45.71; H, 3.16; N, 9.41. Found: C,
45.95; H, 3.38; N, 9.23.
2-(2,4,5-Trichlorophenoxy)-N-(2,40-dioxo-1,2-dihydro-
30H-spiro[indole-3,20-[1,3]thiazolidin]-30-yl)propanamide
(20)
Yield 78 % m.p. 216–218 °C; IR, (KBr, cm-1): 3226
(NH), 3096 (CH-arom.), 2938 (CH-aliph.), 1722 (C=O
isatin), 1711 (C=O thiazolidinone), 1651 (C=O amide). 1H-
NMR (DMSO-d6, d, ppm): 1.61 [d, 3H, CH3], 3.35 [s, 2H,
thiazolidinone-H3], 5.43 [q, 1H, –O–CH–CO], 6.93 [d, 1H,
Ar–H7], 7.09 [t, 1H, Ar–H5], 7.37 [t, 1H, Ar–H6], 7.39 [s,
1H, trichlorophenyl-H6], 7.61 [d, 1H, Ar–H4], 7.88 [s, 1H,
trichlorophenyl-H3], 11.24 [s, 1H, CONH, D2O exchange-
able], 13.55 [s, 1H, indolinone-NH, D2O exchangeable].
13C-NMR (DMSO-d6, d, ppm): 17.7 (CH3), 63.01 (thia-
zolidinone CH2), 73.02 (thiazolidinone-C2), 75.1 (O–CH–
), 111.1, 116.9, 119.6, 121.0, 122.6, 128.3, 130.4, 130.9,
131.8, 132.0, 133.0, 142.7 (aromatic carbons), 162.4 (two
exocyclic CO), 167.5 (C=O). Mass m/z [%]: 486 [M??2]
(8.9), 484 [M?] (9.1), 61 (100). Anal. Calcd. for
C19H14Cl3N3O4S: C, 46.88; H, 2.90; N, 8.63. Found: C,
47.03; H, 2.71; N, 8.41.
2-(2,4,5-Trichlorophenoxy)-N-(2-methyl-4-oxo-2-p-
tolylthiazolidin-3-yl)propanamide (18)
Yield 80 % m.p. 154–155 °C; IR, (KBr, cm-1): 3175
(NH), 3031 (CH-arom.), 2973 (CH-aliph.), 1692 (C=O
1
thiazolidinone), 1667 (C=O amide). H-NMR (DMSO-d6,
d, ppm): 1.50 [d, 3H, CH3], 2.26 [s, 3H, thiazolidinone-5-
CH3], 2.36 [s, 3H, Ar–4-CH3], 3.35 [s, 2H, thiazolidinone-
H3], 4.94 [q, 1H, –O–CH–CO], 7.20 [d, 2H, Ar–H3, Ar–
H5], 7.31 [s, 1H, trichlorophenyl-H6], 7.60 [d, 2H, Ar–H2
and Ar–H6], 7.83 [s, 1H, trichlorophenyl-H3], 10.37 [s,
1H, CONH, D2O exchangeable]. 13C-NMR (DMSO-d6, d,
ppm): 13.60 (Ar–CH3), 18.60 (CH3), 20.80 (CH3), 25.03
(thiazolidinone N–CH–S), 72.34 (thiazolidinone CH2),
73.93 O–CH–), 115.60, 123.59, 126.34, 128.89, 130.05,
130.87, 134.98, 138.90, 149.47, 152.80 (aromatic carbons),
167.0 (thiazolidinone C=O), 171.28 (C=O). Mass m/z [%]:
474 [M??2] (5.7), 472 [M?] (5.4), 62 (100). Anal. Calcd.
for C20H19Cl3N2O3S: C, 50.70; H, 4.04; N, 5.91. Found: C,
50.52; H, 4.25; N, 5.65.
2-(2,4,5-Trichlorophenoxy)-N-(2,40-dioxo-1-(prop-2-ynyl)-
1,2-dihydro-30H-spiro[indole-3,20-[1,3]thiazolidin]-30-
yl)propanamide (21)
Yield 76 % m.p. 177–178 °C; IR, (KBr, cm-1): 3205
(NH), 3082 (CH-arom.), 2937 (CH-aliph.), 2235 (C:C),
1728 (CO isatin) 1712 (C=O thiazolidinone), 1688 (C=O
1
amide). H-NMR (DMSO-d6, d, ppm): 1.55 (d, 3H, CH3),
2.15 (s, 1H, :CH), 3.48 (s, 2H, propynyl-CH2), 3.71 (s,
2H, thiazolidinone-H3), 4.83 (q, 1H, –O–CH–CO), 7.09 (d,
1H, Ar–H7), 7.18 (s, 1H, trichlorophenyl-H6), 7.2 (t, 1H,
123

Med Chem Res
Ar–H5), 7.32 (t, 1H, Ar–H6), 7.57 (s, 1H, trichlorophenyl-
H3), 7.84 (d, 1H, Ar–H4), 11.50 (s, 1H, CONH). Mass m/z
[%]: 524 [M??2] (10.7), 522 [M?] (11.0), 62 (100). Anal.
Calcd. for C22H16Cl3N3O4S: C, 50.35; H, 3.07; N, 8.01.
Found: C, 50.61; H, 3.25; N, 7.83.
Protein Data Bank (Mansour et al., 2007). The co-crys-
tallised ligand was docked in its original protein structure.
Docking was performed with default settings to obtain a
population of possible conformations and orientations for
˚
the inhibitors at the binding site. A 10-A sphere around the
centre of the binding pocket was defined as binding pocket
for the docking runs. All torsion angles in each compound
were allowed to rotate freely.
Antimicrobial evaluations
Compounds (2–21) were evaluated for their in vitro anti-
microbial activity against Gram positive bacteria: S. aureus
(ATCC 25923), B. subtilis (ATCC 10400), Gram negative E.
coli (ATCC 25922), P. aeruginosa (ATCC 27855), Shig.
Sonnei (ATCC 11060) and fungal strains: C. albicans
(ATCC 10231). Antimicrobial activity was assessed by
serial twofold dilution technique (Madhukar et al., 2009).
Ciprofloxacin was used as a standard drug for antibacterial
activity and miconazole was used as a standard drug for
antifungal activity. All the compounds were dissolved in
Conclusion
It was concluded that thiazolidinone analogues (12–21)
are selectively active against the tested Gram positive
bacteria. Compounds 13 and 17 were found equipotent
with the reference drug, chloramphenicol, with MIC value
6.25 lg ml-1. A good correlation was found between the
in silico generated model and the reported X-ray structure
with similar hydrogen bonding and orientation inside the
binding site. On the other hand, the hydrazide-hydrazone
derivatives (2–11) showed no antimicrobial activity.
dimethyl sulfoxide to give a concentration of 100 lg ml-1
.
Twofold dilutions of test and standard compounds were
prepared in double strength nutrient broth (bacteria) or
Sabouraud dextrose broth (fungi). The stock solution was
serially diluted to give concentrations of 100–6.25 lg ml-1
in nutrient broth. The inoculum size was approximately 106
colony forming units (CFU)/ml. The tubes were incubated at
37 1 °C for 24 h (bacteria) and 25 °C for 7 days (fungi).
After that, the inoculated culture tubes were macroscopi-
cally examined for turbidity. The culture tube showing tur-
bidity (lower concentration) and the culture tube showing no
turbidity (higher concentration) gave the minimum inhibi-
tory concentration (MIC) for the compound.
Acknowledgments The author is grateful to the sponsorship of the
Research Centre of College of Pharmacy, and to the deanship of
scientific research, King Saud University, Saudi Arabia.
References
Andres CJ, Bronson JJ, D’Andrea SV, Despande MS, Falk PJ, Grant-
Young KA, Harte WE, Ho HT, Misco PF, Robertson JG, Stock D,
Sun Y, Walsch AW (2000a) 4-Thiazolidinones: novel inhibitors
of the bacterial enzyme MurB. Bioorg Med Chem Lett 10:
715–717
Antimycobacterium tuberculosis activity
Andres C, Bronson JV, D’Andrea S, Deshpande M, Falk P, Grant-
Young K, Harte W, Ho H, Misco P, Robertson J, Stock D, Sun Y,
Walsh A (2000b) N-acyl phenylalanine analogues as potent small
molecule VLA-4 antagonists. Bioorg Med Chem Lett 10:
725–727
Babaoglu K, Page MA, Jones VC, McNeil MR, Dong C, Naismith JH,
Lee RE (2003) Novel inhibitors of an emerging target in
mycobacterium tuberculosis; substituted thiazolidinones as
inhibitors of dTDP-rhamnose synthesis. Bioorg Med Chem Lett
13:3227–3230
Badorc A, Bordes MF, DeCointel P, Savi P, Lale A, Petitou M,
Maffrand JP, Herbert JM (1997) New orally active non-pep-
tide fibrinogen receptor (GpIIb-IIIa) antagonists: identification
of ethyl 3-[N-[4-[4-[amino[(ethoxycarbonyl) imino]methyl]
phenyl]-1,3-thiazol-2-yl]-N-[1-[(ethoxycarbonyl)methyl]piperid-
4-yl]amino]propionate (SR121787) as a potent and long-acting
antithrombotic agent. J Med Chem 40:3393–3401
Bolognese A, Correale G, Manfra M, Lavecchia A, Novellino E,
Barone V (2004) Thiazolidin-4-one formation. Mechanistic and
synthetic aspects of the reaction of imines and mercaptoacetic
acid under microwave and conventional heating. Org Biomol
Chem 2:2809–2813
Preliminary screening of compounds 2–21 for their in vitro
antituberculosis was conducted at 100 lg ml-1 against
M. tuberculosis H37Rv in BACTEC 12B medium using a
broth microdilution assay, the MABA (Collins and Fran-
zblau, 1997). Rifampin was used as the standard in the
tests. None of the compounds were considered for further
evaluation as they had mycobacterial inhibitions less than
90 % at more than 200 lg ml-1 (Ku¨c¸u¨kgu¨ze et al., 2006).
Docking procedure
All molecular modelling studies were performed on PC
windows Vista Home Premium Intel(R) Core(TM)2
Duo, 1.83 GHz using Dock6.4 (Lang et al., 2009). All
compounds were generated in the protonation state
under physiological condition. The coordinates of UDP-
N-acetylmuramate dehydrogenase (MURB) enzyme X-ray
structure, complexed with its co-crystallised ligand naph-
thyl tetronic acid inhibitor, (2Q85) was taken from the
Bronson JJ, DenBleyker SKL, Falk PJ, Mate RA, Ho HT, Pucci MJ,
Snyder LB (2003) Discovery of the first antibacterial small
123

Med Chem Res
molecule inhibitors of MurB. Bioorg Med Chem Lett 13:873–
875
from 4-thiazolidinone combinatorial libraries. Bioorg Med Chem
Lett 6:707–712
Bukowski L, Janowiec M, Zwolska-Kwiek Z, Andrezejczyk Z (1998)
Some reactions of 2-(cyanomethyl)imidazo[4,5-b]pyridine with
isothiocyanates. Antituberculotic activity of the obtained com-
pounds. Pharmazie 53:373–376
Madhukar A, Kannappan N, Aakashdeep I, Kumar P, Kumar M,
Verma P (2009) Synthesis and antimicrobial studies of biphenyl-
4-carboxylic acid 2-(aryl)-4-oxothiazolidin-3-ylamide. Int
Chem Tech Res 1:1376–1380
J
Capan G, Ergenc N, Ekinci AC, Vidin A (1996) Synthesis and
anticonvulsant activity of new 3-(2-furylcarbonylamino)-4-thia-
zolidinone and 2-(2-furylcarbonylhydrazono)-4-thiazoline deriv-
atives. Il Farmaco 51:729–732
Chikhalia KH, Vashi DB, Patel MJ (2009) Synthesis of a novel class
of some 1,3,4-oxadiazole derivatives as antimicrobial agents.
J Enzym Inhib Med Chem 24:617–622
Collins L, Franzblau SG (1997) Microplate alamar blue assay versus
BACTEC 460 system for high-throughput screening of com-
pounds against Mycobacterium tuberculosis and Mycobacterium
avium. Antimicrob Agents Chemother 41:1004–1009
Dessen A, DiGuilmi AM, Vernet T, Dideberg O (2001) Molecular
mechanisms of antibiotic resistance in Gram-positive pathogens.
Curr Drug Targets Infect Disord 1:63–77
Diurno MV, Mazzoni O, Calignano PE, Giordano F, Bolognese A
(1992) Synthesis and antihistaminic activity of some thiazolidin-
4-ones. J Med Chem 35:2910–2912
Ergenc N, Capan G (1994) Synthesis and anticonvulsant activity of
new 4-thiazolidone and 4-thiazoline derivatives. Il Farmaco 49:
133–135
Fahmy HTY (2001) Synthesis of some new triazoles as potential
antifungal agents. Boll Chim Farm 140:422–427
Fuloria NK, Singh V, Yar MS, Ali M (2009) Antimicrobial evaluation
of imines and thiazolidinones derived from 3-phenyl propa-
nehydrazide. Acta Pol Pharm Drug Res 66:141–146
Hyallah A, Radwan AA (2007) Synthesis and quantitative structure
activity relationship of new 3-allyl-5-substituted-tetrahydro-2H-
1,3,5-thiadiazine-2-thiones of potential antimicrobial activity.
Bull Pharm Sci Assiut Univ 30:39–50
Mansour T, Caulfield CE, Rasmussen B, Chopra R, Krishnamurthy G,
Morris KM, Svenson K, Bard J, Smeltzer C, Naughton S, Antane
S, Yang Y, Severin A, Quagliato D, Petersen PJ, Singh G (2007)
Crystal structure of E. coli MurB bound to a napthyl tetronic acid
inhibitor. doi:10.2210/pdb2q85/pdb
Mistry BM, Jauhari S (2012) Synthesis and in vitro antimicrobial and
anti-tubercular evaluation of some quinoline-based azitidinone
and thiazolidinone analogues. Med Chem Res. doi:10.1007/
s00044-012-0060-8
Mostafa YA-H, Hussein MA, Radwan AA, Kfafy A-HN (2008)
Synthesis and antimicrobial activity of certain new 1,2,4-
triazolo[1,5-a]pyrimidine derivatives. Arch Pharm Res 31:279–
293
Muroi H, Nihei K, Tsujimoto K, Kubo I (2004) Synergistic effects of
anacardic acids and methicillin against methicillin resistant
Staphylococcus aureus. Bioorg Med Chem 12:583–587
Pfeltz RF, Wilkinson BJ (2004) The escalating challenge of
vancomycin resistance in Staphylococcus aureus. Curr Drug
Targets Infect Disord 4:273–294
Radwan AA, Hussein NA (2006) Synthesis and antimicrobial activity
of aome 3-(1-phenylethyl)-5-substituted-2H-tetrahydro-1,3,5-
thiadiazine-2-thione derivatives. Bull Pharm Sci Assiut Univ
28:255–260
Roberts MC (2004) Distribution of macrolide, lincosamide, strep-
togramin, ketolide and oxazolidinone (MLSKO) resistance genes
in Gram-negative bacteria. Curr Drug Targets Infect Disord 4:
207–215
Rzasa M, Shea HA, Romo D (1998) Total synthesis of the potent,
immunosuppressive marine agent (–)-pateamine A from Mycale
sp. employing a b-lactam-based macrocyclization. J Am Chem
Soc 120:591–592
Solankee AN, Patel KP, Patel RP (2012) A facile synthesis and
studies of some new 4-thiazolidinones and 5-arylidenes. Adv
Appl Sci Res 3:117–122
Karali N, Ilhan E, Gursoy A, Kiraz
M (1998) New cyl-
cohexylidenehydrazide and 4-aza-1-thiaspiro [4.5] decan-3-one
derivatives of 3-phenyl-4(3H)-quinazolinones. Il Farmaco 53:
346–349
Khan SA, Yusuf M (2009) Synthesis and biological evaluation of
some thiazolidinone derivatives of steroid as antibacterial agents.
Eur J Med Chem 44:2597–2600
Ku¨c¸u¨kgu¨ze G, Kocatepe A, DeClercq E, S¸ahin F, Gu¨llu¨ce M (2006)
Synthesis and biological activity of 4-thiazolidinones, thiose-
micarbazides derived from diflunisal hydrazide. Eur J Med
Chem 41:353–359
Kumar D, Bux FB, Parmar V, Singh A (2012) Thiazolidinone: synthesis
and biological studies. Der Pharma Chemica 4:538–543
Lang PT, Brozell SR, Mukherjee S, Pettersen ET, Meng EC, Thomas
V, Rizzo RC, Case DA, James TL, Kuntz ID (2009) Dock 6:
combining technique to model RNA-small molecule complexes.
RNA 15:1219–1230
Tenover FC, McDonald LC (2005) Vancomycin-resistant staphylo-
cocci and enterococci: epidemiology and control. Curr Opin
Infect Dis 18:300–305
Ulusoy N (2002) Synthesis and antituberculosis activity of cyclo-
alkylidene hydrazide and 4-aza-1-thiaspiro[4,5]decan-3-one
derivatives of imidazo[2,1-b]thiazole. Arzneim-Forsch-Drug
Res 52:565–571
Vagdevi HM, Vaidya VP, Latha KP, Padmashali B (2006) Synthesis
and pharmacological examination of some thiazolidinone deriv-
atives of naphtho[2,1-b]furan. Ind J Pharm Sci 68:719–725
Zhong J (2011) Muscarine, imidazole, oxazole, and thiazole alka-
loids. Nat Prod Rep 28:1143–1191
Look GC, Schullek JR, Homes CP, Chinn JP, Gordon EM, Gallop
MA (1996) The identification of cyclooxygenase-1 inhibitors
123