Aldol derivatives of Thioxoimidazolidinones as potential anti-prostate cancer agents

Article abstract of DOI:10.1016/j.ejmech.2011.04.050

The paper discusses the synthesis and stereochemical aspects of the anti aldol products, 3-(substituted phenyl)-5-[(substituted phenyl) hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidines. The stereochemistry observed in the aldol reactions with benzaldehydes was explained by transition state model of the endocyclic (E)-enolate formed from the rigid 4-oxo-2-thioxoimidazolidine skeleton. Proton NMR and ROESY spectral analyses were carried out to identify the syn and anti conformations of the aldol diastereomers. Configurations of the enantiomers of the representative anti aldol product 3-(4-chlorophenyl)-5-[(4- chlorophenyl) hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine was determined by single crystal XRD studies. The compounds were screened in vitro against prostate cancer cell lines, PC-3 and LNCaP and the most potent derivatives were identified.

Full text of DOI:10.1016/j.ejmech.2011.04.050

European Journal of Medicinal Chemistry 46 (2011) 3291e3301
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Aldol derivatives of Thioxoimidazolidinones as potential anti-prostate
cancer agents
,
Gopal L. Khatik a, Jasmine Kaur b, Varun Kumar a, Kulbhushan Tikoo b, P. Venugopalan c, Vipin A. Nair a
*
a Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, Mohali, Punjab 160 062, India
b Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, Mohali, Punjab 160 062, India
c Department of Chemistry, Panjab University, Chandigarh, Punjab 160 014, India
a r t i c l e i n f o
a b s t r a c t
Article history:
The paper discusses the synthesis and stereochemical aspects of the anti aldol products, 3-(substituted
phenyl)-5-[(substituted phenyl) hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidines. The stereo-
chemistry observed in the aldol reactions with benzaldehydes was explained by transition state model of
the endocyclic (E)-enolate formed from the rigid 4-oxo-2-thioxoimidazolidine skeleton. Proton NMR and
ROESY spectral analyses were carried out to identify the syn and anti conformations of the aldol dia-
stereomers. Configurations of the enantiomers of the representative anti aldol product 3-(4-chlor-
ophenyl)-5-[(4-chlorophenyl) hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine was determined
by single crystal XRD studies. The compounds were screened in vitro against prostate cancer cell lines,
PC-3 and LNCaP and the most potent derivatives were identified.
Received 10 December 2010
Received in revised form
18 April 2011
Accepted 19 April 2011
Available online 29 April 2011
Keywords:
Thioxoimidazolidinone
Aldol
Ó 2011 Elsevier Masson SAS. All rights reserved.
Prostate
Androgen
1. Introduction
Recently thioxoimidazolidinones were reported as anti-prostate
cancer agents, selectively inhibiting the androgen receptor (Fig. 2)
Prostate cancer [1] has emerged as the second leading cause of
cancer deaths in males [2e6]. Though the development of prostate
cancer is mainly related to androgens and androgen receptor, the
exact cause is still unknown. Currently androgen antagonists are
being used in the treatment of prostate cancer, which involves two
classes of compounds, steroidal and non-steroidal (Fig. 1) [7,8].
Although non-steroidal compounds are more preferred due to
lesser cross-reactivity with other receptors [9], they have several
limitations such as resistance to therapy arising from mutation,
development of relapse as a result of the outgrowth of androgen
independent tumour cells, metastasis and hepatotoxicity. The
drawbacks of currently available prostate cancer drugs emphasise
the urgent need to develop novel therapeutic agents to control
metastatic prostate cancer.
[18]. Our interests and research works on biologically active hetero-
cyclic scaffolds [19e23] resulted in identifying a new class of antag-
onists based on 4-oxo-2-thioxoimidazolidine; their synthesis,
stereochemical aspects and preliminary biological results are dis-
cussed herein. The target molecules were designed on the basis of
structure based approach, considering the structures of the marketed
non-steroidal anti-prostate cancer agents. The chiral hydroxy group
of (R)-bicalutamide plays a crucial role in hydrogen bonding
2-Thioxoimidazolidinones which are highly useful synthetic
intermediates, have found a myriad of applications in the area
of therapeutics [10e14]. The 3,5-disubstituted-2-thioxoimidazo-
lidinones and their nucleosides exhibit high potency against the
Herpes Simplex Virus (HSV) [13], Human Immunodeficiency Virus
(HIV)[14]and leukaemia[14]. Theskeleton alsoformsanintegralpart
of COX inhibitors [15] and fatty acid amide hydrolase inhibitor
templates [16,17].
* Corresponding author. Tel.: þ91 172 2292045; fax: þ91 172 2214692.
E-mail addresses: vn74nr@yahoo.com, vnair@niper.ac.in (V.A. Nair).
Fig. 1. Steroidal (A) and non-steroidal (B) anti-prostate cancer agents.
0223-5234/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2011.04.050

3292
G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
of the 1H NMR spectra of the isolated diastereomers revealed that
in the case of diastereomer 6(a)(iv) the C5 methyl protons were
shielded, resonating at 1.45 ppm in comparison to the other isomer
6’(a)(iv) where the methyl protons resonated at 1.76 ppm (Table 1).
ROESY spectrum of the isomer 6(a)(iv) showed a very intense
interaction between the phenyl and methyl groups (Refer the
supplementary data Fig. S1 and Fig. S2) and therefore it may be
assumed that this diastereomer for which the methyl protons are
shielded, the methyl adopts a syn relationship with the phenyl
group and an anti relationship with the hydroxy group while for
diastereomer 6’(a)(iv) with methyl protons deshielded, the phenyl
and hydroxy groups are oriented anti and syn, respectively to the
methyl group. Thus it can be concluded that aldol reaction of the 4-
oxo-2-thioxoimidazolidine 4(a) with benzaldehyde 5(iv) afforded
the anti isomer as the major product, which is widely observed to
be the case with enolates of cyclic and acylic systems with E
geometry [28e34]. With 4-halobenzaldehydes 5(ieiii) we
observed diastereospecificity as only one diastereomer was formed,
irrespective of the lithium base (n-BuLi, LDA or LHMDS) employed
with no appreciable variations either in yield or selectivity.
Comparison of the 1H NMR spectra of syn and anti diastereomers
obtained from benzaldehyde with the diastereomers 6(aef)(ieiii)
formed from 4-halobenzaldehydes, provided sufficient grounds to
believe that the product formed exclusively was the anti isomer in
all the cases. To demonstrate this, the 1H NMR methyl shifts of the
diastereomer 6(a)(iv) and 6’(a)(iv) are compared with 6(a)(ii) in
Table 1. Observation of the diastereospecificity is intriguing and
may be attributed to stereoelectronic factors, while the precise
reasons need to be investigated by computational methods.
Fig. 2. Biologically important scaffolds based on imidazolidinone.
interactions with Leu-704 and Asn-705 of the androgen receptor as
revealed by the X-ray crystal structure of the mutant W741L AR
bound to (R)-bicalutamide [24,25]. Also the (R)-bicalutamide adopts
a bent conformation with the hydroxy group making direct contacts
with the residues of helix 12 of the androgen receptor. These aspects
along with detailed examination of other possible hydrogen bonding
and van der Waals interactions invoked in us the idea of having an
analogous conformationally restricted molecule incorporating the
salient features of bicalutamide, nilutamide and flutamide. A conve-
nient approach to this was to lock the amide nitrogen by suitably
substituted functional groups at the position alpha to the amide
carbonyl and this led to the conceptualisation of 3-(substituted
phenyl)-5-[(substituted phenyl) hydroxy methyl]-5-methyl-4-oxo-
2-thioxoimidazolidines as anti-prostate cancer agents.
2. Results and discussion
Aryl isothiocyanates 2(aef) prepared from the anilines 1(aef)
The anti diasteroselectivity can be explained from the transition
states illustrated in Fig. 3. The phenyl and methyl groups are in
a diequatorial conformation in the transition state TS-I and this is
possible only if they are trans to each other. Energetically this would
be the most stable conformation and the diaxial trans conformer
would be much less favored. The transition state TS-II with the
methyl group oriented axial and the phenyl group disposed equa-
torial represents a cis isomer and is less stable when compared to
the diequatorial trans conformer. The most stable diequatorial
conformation would thus lead to an anti diastereoselectivity in
product formation. An assignment of the stereochemistry would
indicate that the transition state TS-I would lead to (S,R) configu-
rations at C5 and C6 for the anti aldol and (R,S) for its enantiomer
whereas the syn aldol arising from the transition state TS-II will
have the configurations (R,R), and (S,S) for its enantiomer.
[26], were cyclized using D/L-alanine in the presence of triethylamine
in a mixture of dioxaneewater as the medium followed by addition
of conc. HCl to afford 3-(substituted phenyl)-5-methyl-4-oxo-2-
thioxoimidazolidines 3(aef) [27]. The free NH group of the 4-oxo-2-
thioxoimidazolidines were protected using di-tert-butyl dicarbonate
with N,N-dimethylaminopyridine (DMAP) and triethylamine in DCM
to afford 4(aef). Aldol reactions were performed with 4-hal-
obenzaldehydes 5(ieiii) using LDA, and the resultant adducts
6(aef)(ieiii) were deprotected using methanolic HCl to yield 3-
(substituted phenyl)-5-[(substituted phenyl) hydroxy methyl)]-5-
methyl-4-oxo-2-thioxoimidazolidines 7(aef)(ieiii) (Scheme 1).
As a model reaction, 3-(4-chlorophenyl)-5-methyl-4-oxo-2-
thioxoimidazolidine 4(a) was reacted with benzaldehyde 5(iv)
using LDA (Scheme 2). The resultant anti and syn aldol adducts
6(a)(iv) and 6’(a)(iv) were obtained in the ratio 70:30. Examination
Scheme 1. Synthesis of 3-(substituted phenyl)-5-[(substituted phenyl) hydroxy methyl)]-5-methyl-4-oxo-2-thioxoimidazolidines.

G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
3293
Fig. 3. Transition state models for the formation of anti and syn aldol diastereomers.
The conformation of 6(a)(ii) is greatly facilitated through
intramolecular hydrogen bonding which is evident from the proton
signal at 7.30 ppm and hence strongly internally bonded hydroxy
group might have failed to undergo derivatization while the
hydroxy signal at 2.50 ppm for 7(a)(ii) indicated the absence of
intramolecular hydrogen bonding. Thus a third chiral centre of
known and fixed configuration was incorporated, thereby con-
verting the two enantiomers of 7(a)(ii) into diastereomers 9(a)(ii)
and 9’(a)(ii) which were conveniently separated using preparative
thin layer chromatography and characterized by 1H NMR (Table 2).
The configurations were confirmed by single crystal X-ray
analysis. Though diastereomers 9(a)(ii) and 9’(a)(ii) were subjected
to crystallization, suitable crystals were formed only for diaste-
reomer 9(a)(ii) which was analyzed and a perspective view of this
diastereomer with the atom numbering is given in Fig. 4. The
crystal structure shows that the stereochemistry at C5 and C6 are
(S,R) for diastereomer 9(a)(ii) of the anti aldol MPA ester. Conse-
quently diastereomer 9’(a)(ii) of the anti aldol MPA ester should
have the opposite configuration (R,S) at the chiral centres; it being
the other anti aldol enantiomer.
Scheme 2. Anti and syn isomers of 3-(4-chlorophenyl)-5-(phenyl hydroxy methyl)-5-
methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl ester.
Efforts were then directed to confirm the stereochemistry of the
anti aldol products. To separate the enantiomers of the anti aldol,
chiral derivatisation of 6(a)(ii) was tried with (R)-a-methox-
yphenylacetic acid (R-MPA) [35e37], retaining the tert-butylox-
ycarbonyl group, owing to the apprehension that after deprotection
the free nitrogen of the thioxoimidazolidinone may interfere with
the subsequent reaction. But the reaction failed under the condi-
tions attempted (Scheme 3). Subsequently the deprotected
compound 7(a)(ii) was subjected to reaction with (R)-MPA using N-
(3-dimethylaminopropyl)-N’-ethylcarbodiimide
hydrochloride
(EDC.HCl) and DMAP in DCM. Quite interestingly the hydroxy group
underwent derivatization without any interference from nitrogen
of the thioxoimidazolidinone (Scheme 3).
Table 1
The anti aldol adducts of 5-methyl-3-(substituted phenyl)-4-
oxo-2-thioxoimidazolidines 7(aef)(ieiii) were then subjected to
biological evaluation on prostate cancer cell lines. The cytotoxicity
of the thioxoimidazolidinones were studied in vitro on PC-3 and
LNCaP prostate cancer cell lines with doxorubicin and flutamide
respectively as the positive controls. Each cell line was treated with
Chemical shift (ppm) comparison of aldol diastereomers.
Entry
Product
Methyl
t-Butyl
solutions of 0.001 nMe100 mM of the test compound. All the anti
aldol diastereomers were found to decrease the cell viability as
determined by colorimetric MTT assay, with IC50 values ranging
from micromolar to nanomolar concentrations (Table 3). Interest-
ingly none of the compounds exhibited agonistic effect on LNCaP
cells. For the highly active compounds plots of %viability against
1
1.76
1.43
2
1.45
1.39
3
1.44
1.39
Scheme 3. Chiral derivatization of secondary alcohol with (R)-MPA.

3294
G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
Table 2
Table 3
Chemical shift (ppm) comparison of (R)-MPA esters of 7(a)(ii).
Cytotoxic activity of compounds on PC-3 and LNCaP prostate cancer cell lines by MTT
assay.a,b
Entry
Product
H of NH of
(R)- thioxo-imi
MPA dazolidinone
Entry
Compound
R1
R2
R3
IC50
cells
(
mM) on PC-3
IC50 (mM) on
LNCaP cells
1
2
3
Doxorubicinc
Flutamidec
7(a)(i)
e
e
e
e
F
1.03
ndd
1.23
ndd
0.90
0.86
e
e
Cl
H
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
7(a)(ii)
7(a)(iii)
7(b)(i)
7(b)(ii)
7(b)(iii)
7(c)(i)
7(c)(ii)
7(c)(iii)
7(d)(i)
7(d)(ii)
7(d)(iii)
7(e)(i)
7(e)(ii)
7(e)(iii)
7(f)(i)
7(f)(ii)
7(f)(iii)
Cl
Cl
F
F
F
Cl
Cl
Cl
CN
CN
CN
CN
CN
CN
NO2
NO2
NO2
H
H
Cl
Cl
Cl
Br
F
Cl
Br
F
Cl
Br
F
Cl
Br
F
Cl
Br
F
Cl
Br
>100
>100
>100
>100
>100
>100
1.24
0.923
>100
>100
>100
>100
0.988
1.15
>100
>100
>100
98.2
1
4.782 7.088
Cl
w100
w100
0.960
0.500
93.200
>100
w100
w100
0.507
0.880
33
CF3
CF3
CF3
Cl
Cl
Cl
CF3
CF3
CF3
CF3
CF3
CF3
89
1.19
>100
0.939
73.4
a
The data represents the mean of three experiments.
The (ꢁ) anti aldol isomers were screened.
Used as a positive control.
nd ¼ not determined.
b
c
2
4.756 7.043
d
withdrawing groups Cl and CF3 at the para and meta positions,
exhibited the highest toxicity with IC50 values of 0.92 M on PC-3
cells and 0.50 M on LNCaP cells. Most of the reported anti-
m
m
prostatic compounds contain the functional groups CN and CF3 or
NO2 and CF3 at the para and meta positions in the aromatic A ring of
the parent skeleton [8,38,39]. But a similar substitution on this
pharmacophore did not remarkably improve the outcome
(compare 7(e,f)(ieiii) with 7(c)(ii,iii), Table 3). It was also observed
that the substituent on the aromatic B ring played a prominent role
with the activity decreasing in the order Br ꢀ Cl >>>> F. The
general cytotoxicity of these compounds was examined on the non-
doses for PC-3 and LNCaP cell lines are provided (Figs. 5 and 6).
Toxicity studies on LNCaP cells may suggest an androgen depen-
dent mechanistic pathway. The corresponding thioxooxazolidinone
derivatives synthesized by an analogous procedure [21] exhibited
poorer activity on PC-3 and LNCaP cell lines with IC50 values in the
range of 100 mM or more (Refer the Supplementary data, Table S1),
cancerous cells MCF-10A, and found to be non-toxic at 1.0
mM
which illustrated the significance of the thioxoimidazolidinone
scaffold. Compounds 7(a)(i), 7(c)(ii), 7(c)(iii), 7(e)(ii), 7(e)(iii) and
7(f)(ii) showed activity equal to or better than the standards
doxorubicin and flutamide on both PC-3 and LNCaP cell lines.
Compound 7(c)(iii), with an aryl A ring bearing the electron
concentration. Also a low level of toxicity on breast cancer cells
MCF-7 gave convincing evidence for the selectivity of these
compounds towards prostate cancer cells (Refer the supplementary
data, Fig. S13). The biological evaluation of the newly synthesized
4-oxo-2-thioxoimidazolidine derivatives further helped in identi-
fying a highly potent pharmacophore based on 5-methyl-3-
Fig. 4. ORTEP diagram of the diastereomer 9(a)(ii), hydrogen atoms were omitted for
clarity.
Fig. 5. Dose-response curves of most potent compounds on PC-3 cells.

G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
3295
dichloromethane (DCM) 4-chloroaniline (Merck) and sodium
hydrogen carbonate (CDH).
4.2. General procedure for the synthesis of aryl isothiocyanates 2
In a typical experiment, a solution of sodium hydrogen carbonate
(62.72 mmol) in 20 mL of water was stirred for 10 min and to it was
added dichloromethane (20 mL) followed by substituted aniline
(15.68 mmol). The reaction mixture was cooled to 0 ꢂC, thiophosgene
(23.52 mmol) was introduced dropwise over a period of 30 min and
continuously stirred at room temperature for 1 h. The reaction
mixture was washed with brine solution; the organic layer was dried
over anhydrous sodium sulphate and concentrated to get a crude
gummy compound which was recrystalized in hexane under cold
condition. The precipitate was filtered and dried to get the desired
compound. The products were characterized by analytical and
spectral methods.
Fig. 6. Dose-response curves of most potent compounds on LNCaP cells.
4.2.1. 4-chlorophenyl isothiocyanate 2(a)
Yield 81%; white solid; mp 134e136 ꢂC 1H NMR (400 MHz,
CDCl3) d 7.12e7.18 (m, 2H), 7.31e7.36 (m, 2H); MS: m/z (GC-MSMS)
(substituted phenyl)-5-[(substituted phenyl) hydroxy methyl]-
4-oxo-2-thioimidazolidine skeleton. Further, the asymmetric syn-
thesis of the active anti aldol enantiomer of the representative
compound has to be carried out and its pharmacological properties
need to be investigated in depth.
169.03 (M)þ.
4.2.2. 3-chloro-4-fluorophenyl isothiocyanate 2(b)
Yield 75%; colourless oil; 1H NMR (400 MHz, CDCl3)
d 7.09e7.16
(m, 2H), 7.29e7.37 (m, 1H); MS: m/z (GC-MSMS) 187.01 (M)þ.
3. Conclusions
4.2.3. 4-chloro-3-trifluoromethylphenyl isothiocyanate 2(c)
Yield 70%; colourless oil; 1H NMR (400 MHz, CDCl3)
d 7.31e7.34
The aldol reactions of 5-methyl-3-(substituted phenyl)-4-oxo-2-
thioxoimidazolidines afforded the anti isomer stereospecifically.
Biological evaluations of the anti isomers on PC-3 and LNCaP pros-
tate cancer cells demonstrated inhibition of cell growth. The highly
potent compound 7(c)(iii) demonstrated cytotoxicity better than
doxorubicin and flutamide on PC-3 and LNCaP cells respectively.
Further development of this scaffold may help to discover a poten-
tial therapeutic for the control and prevention of prostate cancer.
(m, 1H), 7.42e7.54 (m, 2H); MS: m/z (GC-MSMS) 237.07 (M)þ.
4.2.4. 3-chloro-4-cyanophenyl isothiocyanate 2(d)
Yield 73%; light yellow solid; mp 85e90 ꢂC; 1H NMR (300 MHz,
CDCl3)
d
7.18e7.22 (m,1H), 7.34 (d, J ¼ 8.4 Hz,1H), 7.66 (d, J ¼ 8.4 Hz,
1H); MS: m/z (GC-MSMS) 193.96(M)þ.
4.2.5. 4-cyano-3-trifluoromethylphenyl isothiocyanate 2(e)
Yield 65%; yellow oil; 1H NMR (400 MHz, CDCl3)
d 7.46e7.49
4. Experimental
(m, 1H), 7.59 (d, J ¼ 8.2 Hz, 1H), 7.83 (d, J ¼ 8.2 Hz, 1H); MS: m/z
(GC-MSMS) 228.01(M)þ.
4.1. General
4.2.6. 4-nitro-3-trifluoromethylphenyl isothiocyanate 2(f)
The 1H and 13C NMR spectra were recorded at 400 MHz/
300 MHz and 100 MHz/75 MHz, respectively on Bruker Advance
DPX 400/300 spectrometers in CDCl3/CD3OD/(CD3)2SO using TMS
Yield 68%; yellow oil; 1H NMR (400 MHz, CDCl3)
d 7.51e7.53
(m, 1H), 7.62 (d, J ¼ 8.6 Hz, 1H), 7.97 (d, J ¼ 8.6 Hz, 1H); MS: m/z
(GC-MSMS) 248.11(M)þ.
as the internal standard. The chemical shifts (d
) for 1H and 13C are
given in ppm relative to residual signals of the solvent. Coupling
constants are given in Hz. The following abbreviations are used to
indicate the multiplicity: s, singlet; d, doublet; t, triplet; q, quartet;
m, multiplet; brs, broad singlet. The IR spectra were recorded on
a Nicolet Impact Spectrometer as KBr pellets for solid samples.
Mass spectra were recorded on POLARIS Q (Thermo Scientific) GC-
MSMS, Maldi-TOF/TOF. Specific rotations were taken on Rudolph
Autopol IV Instrument and HRMS spectra were recorded on Bruker
Maxis TOF. The reactions were monitored by TLC (Merck). Evapo-
ration of solvents was performed under reduced pressure using
a rotary evaporator. Melting points are uncorrected. Commercial
grade reagents and solvents were used without further purifica-
tion; n-butyllithium, lithium diisopropylamide (LDA), lithium
hexamethyldisilazane (LHMDS), N-(3-dimethylaminopropyl)-N0-
4.3. General procedure for the synthesis of 3-(substituted phenyl)-
5-methyl-4-oxo-2-thioxoimidazolidines 3
In a typical experiment, triethylamine (1.2 mmol) was added to
a solution of aryl isothiocyanate (0.59 mmol) in dioxaneewater
(2 mL:6 mL) mixture at 0 ꢂC. An aqueous solution of
D/L-alanine
(0.7 mmol) was added to it and the solution was stirred for 30 min,
followed by the addition of conc. HCl until the pH became w2. The
reaction mixture was stirred for another 2 h and the precipitate
formed was filtered and dried to yield the desired compound. The
products were characterized by analytical and spectral methods.
4.3.1. 3-(4-chlorophenyl)-5-methyl-4-oxo-2-thioxoimidazolidine 3(a)
ethylcarbodiimide hydrochloride (EDC.HCl), (R)-(-)-
a-methox-
Yield 85%; white solid; mp 203e206 ꢂC; nmax 1755, 3168 cmꢃ1
;
yphenylacetic acid (R-MPA), 4-chloro-3-trifluoromethylaniline,
4-amino-2-chlorobenzonitrile (Aldrich), 4-fluoro-3-chloroaniline,
triethylamine, thiophosgene, 1,4-dioxane, di-tert-butyl dicar-
bonate, N,N-dimethylaminopyridine (DMAP), THF (Spectrochem);
1H NMR (300 MHz, CDCl3)
(m, 1H), 7.28 (d, J ¼ 8.6 Hz, 2H), 7.47 (d, J ¼ 8.6 Hz, 2H), 7.82 (brs, 1H,
d
1.59 (d, J ¼ 7.0 Hz, 3H), 4.32e4.38
NH); 13C NMR (75 MHz, CDCl3)
d 17.58, 56.04, 130.00, 130.10, 131.52,
135.83, 174.32, 183.69; MS: m/z (Maldi TOF/TOF) 241.32 (M þ H)þ.

3296
G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
4.3.2. 3-(3-chloro-4-fluorophenyl)-5-methyl-4-oxo-2-thioxoimida-
zolidine 3(b)
130.17, 130.45, 131.63, 136.10, 149.12, 172.45, 179.31; MS: m/z (Maldi
TOF/TOF) 363.42 (M þ Na)þ.
Yield 87%; white solid; mp 221e224 ꢂC; 1H NMR (400 MHz,
CDCl3)
d
1.61 (d, J ¼ 6.8 Hz, 3H), 4.34e4.40 (m, 1H), 7.28e7.30 (m,
4.4.2. 3-(3-chloro-4-fluorophenyl)-5-methyl-4-oxo-2-thioxoimid-
azolidine-1-carboxylic acid tert-butyl ester 4(b)
2H), 7.43e7.44 (m, 1H), 7.73 (brs, 1H, NH); 13C NMR (100 MHz,
CDCl3)
d
17.05, 55.47, 117.11, 121.84, 128.35, 128.43, 130.78, 157.03,
Yield 93%; white solid; mp 143e146 ꢂC; 1H NMR (300 MHz,
173.61, 182.88; MS: m/z (Maldi TOF/TOF) 259.32 (M þ H)þ.
CDCl3)
7.13e7.17 (m, 1H), 7.29 (s, 1H), 7.32e7.35 (m, 1H); 13C NMR (75 MHz,
CDCl3) 17.40, 28.02, 58.21, 85.61, 117.09, 121.82, 128.81, 128.94,
d
1.61 (s, 9H), 1.73 (d, J ¼ 6.8 Hz, 3H), 4.67e4.72 (m, 1H),
4.3.3. 3-(4-chloro-3-trifluoromethylphenyl)-5-methyl-4-oxo-2-
thioxoimidazolidine 3(c)
d
131.15, 148.49, 157.17, 171.79, 178.50; MS: m/z (Maldi TOF/TOF)
Yield 84%; white solid; mp 185e188 ꢂC; 1H NMR (400 MHz,
381.53 (M þ Na)þ.
CDCl3)
d
1.61 (d, J ¼ 7.2 Hz, 3H), 4.36e4.41 (m, 1H), 7.49e7.51 (m,
1H), 7.64 (d, J ¼ 8.4 Hz, 1H), 7.71 (s, 1H), 7.83 (brs, 1H, NH); 13C NMR
4.4.3. 3-(4-chloro-3-trifluoromethylphenyl)-5-methyl-4-oxo-2-
thioxoimidazolidine-1-carboxylic acid tert-butyl ester 4(c)
Yield 94%; white solid; mp 145e147 ꢂC; 1H NMR (400 MHz,
(100 MHz, CDCl3)
d 17.01, 55.55, 120.85, 123.57, 127.58, 129.12,
131.17, 132.19, 133.20, 173.41, 182.40; MS: m/z (Maldi TOF/TOF)
309.37 (M þ H)þ.
CDCl3)
7.40e7.42 (m, 1H), 7.61e7.66 (m, 2H); 13C NMR (100 MHz, CDCl3)
17.38, 28.02, 58.29, 85.77, 120.79, 128.06, 129.69, 131.23, 132.40,
d
1.62 (s, 9H), 1.75 (d, J ¼ 6.8 Hz, 3H), 4.70e4.75 (m, 1H),
4.3.4. 3-(4-chloro-3-cyanophenyl)-5-methyl-4-oxo-2-thioxoimida-
zolidine 3(d)
d
133.05, 133.58, 148.47, 171.61, 178.07; MS: m/z (Maldi TOF/TOF)
431.51 (M þ Na)þ.
Yield 86%; brick red solid; mp 238e240 ꢂC; 1H NMR (300 MHz,
CDCl3 þ CD3OD)
7.49e7.52 (m, 1H), 7.66e7.67 (m, 1H), 7.83e7.84 (m, 1H); 13C NMR
20.20, 59.58, 116.98, 119.25, 131.41,
d
1.57 (d, J ¼ 7.0 Hz, 3H), 4.35e4.40 (m, 1H),
4.4.4. 3-(4-chloro-3-cyanophenyl)-5-methyl-4-oxo-2-thioxoimida-
zolidine-1-carboxylic acid tert-butyl ester 4(d)
(75 MHz, CDCl3 þ CD3OD)
d
133.92, 137.99, 140.81, 141.72, 178.19, 185.26; MS: m/z (Maldi TOF/
TOF) 266.32 (M þ H)þ.
Yield 90%; white solid; mp 129e131 ꢂC; 1H NMR (300 MHz,
CDCl3)
d
1.61 (s, 9H), 1.74 (d, J ¼ 6.8 Hz, 3H), 4.71e4.73 (m, 1H),
7.33e7.36 (m, 1H), 7.50e7.51 (m, 1H), 7.80 (d, J ¼ 8.2 Hz, 1H); 13C
4.3.5. 4-(4-methyl-5-oxo-2-thioxoimidazolidin-1-yl)-2-(trifluoromethyl)
benzonitrile 3(e)
NMR (75 MHz, CDCl3) d 17.45, 27.66, 58.90, 86.50, 114.79, 115.70,
128.32,131.04,134.88,137.70,138.06,148.93,171.75,177.91; MS: m/z
Yield 70%; white solid; mp 185e188 ꢂC; FTIR (KBr) : cmꢃ1 1H
n ;
(Maldi TOF/TOF) 388.39 (M þ Na)þ.
NMR (300 MHz, CDCl3)
d
1.64 (d, J ¼ 7.0 Hz, 3H), 4.39e4.46 (m, 1H),
7.16 (brs, 1H, NH), 7.79 (d, J ¼ 8.2 Hz, 1H), 7.90 (s, 1H), 7.97
4.4.5. tert-butyl-3-(4-cyano-3-(trifluoromethyl)phenyl)-5-methyl-
4-oxo-2-thioxoimidazolidine-1-carboxylate 4(e)
(d, J ¼ 8.2 Hz, 1H); 13C NMR (75 MHz, CDCl3)
d; 17.08, 55.58, 110.28,
114.76, 127.27, 131.87, 133.03, 133.47, 135.31, 136.55, 172.89, 181.42;
Yield 81%; white solid; mp 134e136 ꢂC; 1H NMR (400 MHz,
MS: m/z (Maldi TOF/TOF) 300.38(M)þ.
CDCl3)
d
1.61 (s, 9H), 1.76 (d, J ¼ 8.0 Hz, 3H), 4.73e4.79 (m, 1H),
7.66e7.68 (m, 1H), 7.79 (s, 1H), 7.98 (d, J ¼ 8.4 Hz, 1H); 13C NMR
4.3.6. 5-methyl-3-(4-nitro-3-(trifluoromethyl)phenyl)-4-oxo-2-
thioxoimidazolidine 3(f)
(100 MHz, CDCl3) d 17.35, 28.01, 58.39, 86.08, 110.83, 114.58, 120.37,
127.51, 132.58, 135.48, 136.59, 148.36, 171.17, 177.18; MS: m/z (Maldi
Yield 85%; yellow solid; 205e208 ꢂC; 1H NMR (300 MHz, CDCl3)
TOF/TOF) 422.54 (M þ Na)þ.
d
1.66 (d, J ¼ 7.0 Hz, 3H), 4.42e4.47 (m, 1H), 7.28 (brs, 1H, NH),
7.81e7.84 (m, 1H), 7.94 (s, 1H), 8.04 (d, J ¼ 8.6 Hz, 1H); 13C NMR
4.4.6. tert-butyl-3-(3-nitro-4-trifluoromethylphenyl)-5-methyl-4-
oxo-2-thioxoimidazolidine-1-carboxylate 4(f)
(75 MHz, CDCl3) d 17.12, 55.52, 125.81, 127.95, 128.01, 131.48, 132.63,
136.14, 172.81, 181.44; MS: m/z (Maldi TOF/TOF) 320.43(M)þ.
Yield 85%; white solid; mp 119e121 ꢂC; 1H NMR (400 MHz,
CDCl3)
d
1.61 (s, 9H), 1.74 (d, J ¼ 8.0 Hz, 3H), 4.75e4.80 (m, 1H),
7.70e7.72 (m, 1H), 7.82 (s, 1H), 8.03 (d, J ¼ 8.5 Hz, 1H); 13C NMR
4.4. General procedure for the synthesis of 3-(substituted phenyl)-5-
(100 MHz, CDCl3) d 17.36, 28.01, 58.48, 86.12, 126.02, 128.71, 128.37,
methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl ester 4
133.42, 136.16, 148.37, 171.21, 177.20.
In a typical experiment, to a dichloromethane solution of 3-
(substituted
phenyl)-5-methyl-4-oxo-2-thioxoimidazolidine
4.5. General procedure for the synthesis of 3-(substituted phenyl)-
5-[(substituted phenyl) hydroxy methyl)-5-methyl-4-oxo-2-
thioxoimidazolidine-1-carboxylic acid tert-butyl ester 6
(27.08 mmol), triethylamine (32.49 mmol) was added at 0 ꢂC.
This was followed by the addition of di-tert-butyl dicarbonate
(32.49 mmol) and N,N-dimethylaminopyridine (0.27 mmol). The
liberation of CO2 along with a change in appearance of the reaction
mixture to yellow was observed. The reaction mixture was stirred
for 30 min, and then washed with 1 N aq. HCl, aq. NaHCO3 solution
and the organic layer was dried and concentrated to get the desired
compound. The products were characterized by analytical and
spectral methods.
In a typical experiment, 3-(substituted phenyl)-5-methyl-
4-oxo-2-thioxoimidazolidin-1-carboxylic acid tert-butyl ester
(4.1 mmol), dissolved in anhydrous THF (50 mL) and cooled
to ꢃ78 ꢂC, was treated with LDA (2.0 mL, 1.8 M solution) under
nitrogen atmosphere and stirred for 30 min. 4-Halobenzaldehyde
(4.9 mmol) was added to the reaction mixture, stirred for another
30 min, then quenched with saturated aq. NH4Cl and extracted
into ethyl acetate. The organic layer was dried and concentrated
to provide a gummy compound. The crude product was purified
by column chromatography on silica gel (60e120 mesh) using
ethyl acetateehexane mixture as the eluent to provide the
desired compound. The products were characterized by analytical
and spectral methods.
4.4.1. 3-(4-chlorophenyl)-5-methyl-4-oxo-2-thioxoimidazolidine-
1-carboxylic acid tert-butyl ester 4(a)
Yield 84%; white solid; mp 149e151 ꢂC; nmax 1755 and
3168 cmꢃ1
;
1H NMR (300 MHz, CDCl3)
d
1.60 (s, 9H), 1.72
(d, J ¼ 4.2 Hz, 3H), 4.68e4.72 (m, 1H), 7.18e7.20 (m, 2H), 7.46e7.49
(m, 2H); 13C NMR (75 MHz, CDCl3)
17.95, 28.13, 58.75, 86.01,
d

G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
3297
4.5.1. 3-(4-chlorophenyl)-5-[(4-fluorophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl
ester 6(a)(i)
HRMS (ESI-TOF) calcd for C22H21BrClFN2O4S ([M þ Na]þ): 564.9976;
found: 564.9983.
Rf 0.44, EtOAcehexane, 3:7; yield 40%; white solid; mp
4.5.7. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-fluorophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(c)(i)
184e186 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 9H), 1.44 (s, 3H),
5.72 (s, 1H), 7.14e7.18 (m, 2H), 7.25e7.27 (m, 2H), 7.41e7.44 (m, 3H),
7.47e7.48 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.72, 27.63, 66.91,
d
Rf 0.47, EtOAcehexane, 3:7; yield 39%; white solid; mp
78.95, 83.69, 116.12, 129.07, 129.15, 129.48, 129.68, 129.72, 131.30,
135.47, 151.47, 173.88, 183.15; HRMS (ESI-TOF) calcd for
C22H22ClFN2O4S ([M þ Na]þ): 487.0871; found: 487.0878.
138e140 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.39 (s, 9H), 1.46 (s, 3H),
5.71 (s, 1H), 7.09 (brs, 1H, OH), 7.15e7.19 (m, 2H), 7.40e7.44 (m, 2H),
7.46e7.49 (m, 1H), 7.64e7.66 (m, 2H); 13C NMR (100 MHz, CDCl3)
d
19.81, 27.55, 66.93, 78.87, 83.89, 116.22, 116.44, 127.80, 127.85,
4.5.2. 3-(4-chlorophenyl)-5-[(4-chlorophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl
ester 6(a)(ii)
129.00, 129.08, 129.54, 131.42, 132.28, 132.87, 151.42, 173.55, 182.30;
HRMS (ESI-TOF) calcd for C23H21ClF4N2O4S ([M þ Na]þ): 555.0745;
found: 555.0752.
Rf 0.41, EtOAcehexane, 3:7; yield 47%; white solid; mp
159e161 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 9H), 1.44 (s, 3H),
5.70 (s,1H), 7.25e7.27 (m, 2H), 7.30 (brs,1H, OH), 7.36e7.39 (m, 2H),
7.44e7.46 (m, 4H), 13C NMR (100 MHz, CDCl3)
19.73, 27.64, 66.70,
4.5.8. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-chlorophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(c)(ii)
d
78.94, 83.76, 128.57, 129.37, 129.48, 129.72, 131.30, 132.39, 135.47,
135.70, 151.44, 173.76, 183.14; HRMS (ESI-TOF) calcd for
C22H22Cl2N2O4S ([M þ Na]þ): 503.0575; found: 503.0581.
Rf 0.47, EtOAcehexane, 3:7; yield 43%; white solid; mp
149e151 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 9H), 1.47 (s, 3H),
5.72 (s, 1H), 7.38e7.40 (m, 2H), 7.45e7.50 (m, 3H), 7.64e7.67
(m, 2H); 13C NMR (100 MHz, CDCl3)
19.71, 27.56, 66.93, 78.93,
d
4.5.3. 3-(4-chlorophenyl)-5-[(4-bromophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl
ester 6(a)(iii)
84.03, 120.84, 123.56, 127.73, 127.78, 128.52, 129.31, 129.63, 131.35,
132.22, 133.47, 135.74, 151.41, 173.53, 182.35; HRMS (ESI-TOF) calcd
for C23H21Cl2F3N2O4S ([M þ Na]þ): 571.0449; found: 571.0456.
Rf 0.41, EtOAcehexane, 3:7; yield 46%; white solid; mp
169e171 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 9H), 1.46 (s, 3H),
5.70 (s, 1H), 7.28e7.30 (m, 2H), 7.33e7.35 (m, 2H), 7.48e7.52
(m, 2H), 7.61e7.63 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.72,
4.5.9. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-bromophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(c)(iii)
d
27.66, 66.73, 79.00, 83.85, 123.84, 128.84, 129.54, 129.73, 131.20,
132.36, 132.88, 135.50, 151.45, 173.81, 183.16; HRMS (ESI-TOF) calcd
for C22H22BrClN2O4S ([M þ Na]þ): 547.0070; found: 547.0067.
Rf 0.47, EtOAcehexane, 3:7; yield 38%; white solid; mp
159e161 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 9H), 1.47 (s, 3H),
5.70 (s, 1H), 7.32e7.34 (m, 2H), 7.48e7.50 (m, 1H), 7.60e7.67 (m,
4H); 13C NMR (100 MHz, CDCl3)
19.72, 27.57, 66.83, 78.98, 84.03,
d
4.5.4. 3-(3-chloro-4-fluorophenyl)-5-[(4-fluorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(b)(i)
120.84, 123.56, 127.73, 128.79, 129.30, 131.35, 131.86, 132.30, 132.75,
132.88, 133.46, 151.41, 173.50, 182.33; HRMS (ESI-TOF) calcd for
C23H21BrClF3N2O4S ([M þ Na]þ): 614.9944; found: 614.9938.
Rf 0.46, EtOAcehexane, 3:7; yield 47%; white solid; mp
188e191 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.43 (s, 9H), 1.45 (s, 3H),
5.74 (s, 1H), 7.16e7.20 (m, 2H), 7.23e7.26 (m,1H), 7.27e7.31 (m,1H),
7.39e7.45 (m, 4H); 13C NMR (100 MHz, CDCl3)
19.59, 27.63, 67.01,
4.5.10. 3-(3-chloro-4-cyanophenyl)-5-[(4-fluorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(d)(i)
d
78.98, 83.91, 116.17, 116.94, 121.79, 128.62, 128.70, 129.06, 129.19,
129.56, 130.91, 151.45, 157.23, 173.84, 182.89; HRMS (ESI-TOF) calcd
for C22H21ClF2N2O4S ([M þ Na]þ): 505.0777; found: 505.0771.
Rf 0.34, EtOAcehexane, 3:7; yield 40%; white solid; mp
206e208 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.41 (s, 9H), 1.47 (s, 3H),
5.75 (s,1H), 7.15e7.20 (m, 2H), 7.41e7.45 (m, 3H), 7.54e7.55 (m,1H),
7.71 (brs, 1H, OH), 7.82 (d, J ¼ 8.4 Hz, 1H); 13C NMR (100 MHz,
4.5.5. 3-(3-chloro-4-fluorophenyl)-5-[(4-chlorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(b)(ii)
CDCl3) d 19.58, 27.60, 67.29, 78.99, 84.07, 114.11, 115.21, 116.20,
129.07, 129.16, 129.37, 129.40, 130.07, 134.25, 137.38, 137.46, 151.35,
173.33, 181.66; HRMS (ESI-TOF) calcd for C23H21ClFN3O4S
([M þ Na]þ): 521.0823; found: 512.0823.
Rf 0.46, EtOAcehexane, 3:7; yield 39%; white solid; mp
179e181 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.42 (s, 9H), 1.46 (s, 3H),
5.73 (s, 1H), 7.24e7.31 (m, 2H), 7.39e7.41 (m, 3H), 7.46e7.48
(m, 2H), 7.71 (brs,1H, OH); 13C NMR (100 MHz, CDCl3)
19.57, 27.65,
4.5.11. 3-(3-chloro-4-cyanophenyl)-5-[(4-chlorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(d)(ii)
d
66.93, 79.00, 84.04, 116.98, 121.82, 128.56, 128.72, 129.11, 129.44,
130.88, 132.20, 135.70, 151.44, 157.24, 173.79, 182.90; HRMS (ESI-
TOF) calcd for C22H21Cl2FN2O4S ([M þ Na]þ): 521.0481; found:
521.0485.
Rf 0.34, EtOAcehexane, 3:7; yield 44%; white solid; mp
197e199 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.41 (s, 9H),1.48 (s, 3H), 5.75
(s, 1H), 7.38e7.47 (m, 5H), 7.54e7.55 (m, 1H), 7.81e7.83 (m, 1H), 8.00
(brs, 1H, OH); 13C NMR (100 MHz, CDCl3)
19.56, 27.60, 67.24, 79.01,
d
4.5.6. 3-(3-chloro-4-fluorophenyl)-5-[(4-bromophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(b)(iii)
84.22, 114.11, 115.20, 127.53, 128.56, 128.92, 129.59, 130.02, 132.05,
134.29, 135.75, 137.29, 151.34, 173.27, 181.69; HRMS (ESI-TOF) calcd
for C23H21Cl2N3O4S ([M þ Na]þ): 528.0526; found: 528.0524.
Rf 0.46, EtOAcehexane, 3:7; yield 44%; white solid; mp
79e82 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.42 (s, 9H), 1.45 (s, 3H), 5.73
4.5.12. 3-(3-chloro-4-cyanophenyl)-5-[(4-bromophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine-1-carboxylic acid
tert-butyl ester 6(d)(iii)
(s, 1H), 7.24e7.26 (m, 2H), 7.33e7.35 (m, 2H), 7.38e7.40 (m, 1H),
7.60e7.62 (m, 2H), 7.98 (brs, 1H, OH); 13C NMR (100 MHz, CDCl3)
d
19.56, 27.67, 66.92, 79.08, 84.08, 117.01, 121.81, 123.86, 128.66,
Rf 0.34, EtOAcehexane, 3:7; yield 37%; white solid; mp
128.84, 129.02, 130.85, 132.38, 132.72, 151.45, 157.23, 173.81, 182.90;
198e200 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.40 (s, 9H), 1.47 (s, 3H),

3298
G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
5.69 (s, 1H), 7.30e7.32 (m, 2H), 7.41e7.43 (m, 2H), 7.53e7.54
(m, 1H), 7.60e7.62 (m, 2H), 7.80e7.82 (m, 1H); 13C NMR (100 MHz,
4.5.18. 5-[(4-bromophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine-1-carboxylic
acid tert-butyl ester 6(f)(iii)
CDCl3)
d 19.63, 27.65, 66.98, 79.04, 84.18, 114.14, 115.21, 124.03,
127.52, 128.78, 130.06, 132.43, 132.56, 134.27, 137.33, 137.50, 151.30,
173.19, 181.61; HRMS (ESI-TOF) calcd for C23H21BrClN3O4S
([M þ Na]þ): 572.0023; found: 572.0011.
Rf 0.32, EtOAcehexane, 3:7; yield 44%; white solid; mp
117e119 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.40 (s, 9H), 1.50 (s, 3H),
5.71 (s, 1H), 7.21 (brs, 1H, OH), 7.32 (d, J ¼ 8.4 Hz, 2H), 7.63
(d, J ¼ 8.4 Hz, 2H) 7.77e7.84 (m, 2H), 8.05 (d, J ¼ 8.5 Hz, 1H); 13C
4.5.13. 5-[(4-fluorophenyl) hydroxy methyl]-3-(4-cyano-3-
trifluoromethylphenyl)-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(e)(i)
NMR (100 MHz, CDCl3) d 19.77, 27.60, 66.90, 78.99, 84.20, 124.10,
125.94, 128.23, 128.73, 128.93, 131.93, 132.46, 132.57, 133.06, 136.33,
151.28, 173.11, 181.29; HRMS (ESI-TOF) calcd for C23H21BrF3N3O6S
([M þ Na]þ): 626.0184; found: 626.0157.
Rf 0.34, EtOAcehexane, 3:7; yield 46%; white solid; mp
197e199 ꢂC; 1H NMR (300 MHz, CDCl3)
d 1.38 (s, 9H), 1.53 (s, 3H),
5.71 (s, 1H), 6.91 (brs,1H, OH), 7.15e7.20 (m, 2H), 7.39e7.43 (m, 2H),
4.5.19. 3-(4-chlorophenyl)-5-(phenyl hydroxy methyl)-5-methyl-4-
oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl ester.
6(a)(iv)
7.73e7.75 (m, 1H), 7.81 (s, 1H), 7.98 (d, J ¼ 8.4 Hz, 1H). 13C NMR
(75 MHz, CDCl3)
d 19.52, 27.24, 64.98, 76.82, 85.46, 127.39, 128.04,
128.17, 128.60, 128.92, 128.97, 129.15, 129.27, 129.30, 133.99, 135.27,
137.81, 172.56, 179.15; HRMS (ESI-TOF) calcd for C24H21F4N3O4S
([M þ Na]þ): 546.1087; found: 546.1081.
Anti isomer: Rf 0.29, EtOAcehexane, 1:3; white solid; mp
176e178 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.39 (s, 9H), 1.44 (s, 3H),
5.73 (s, 1H), 7.25e7.27 (m, 2H), 7.28 (brs, 1H, OH), 7.41e7.42 (m, 1H),
7.43e7.44 (m, 3H), 7.45e7.48 (m, 3H); 13C NMR (100 MHz, CDCl3)
4.5.14. 5-[(4-chlorophenyl) hydroxy methyl]-3-(4-cyano-3-
trifluoromethylphenyl)-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(e)(ii)
d 19.83, 27.65, 66.90, 79.56, 83.42, 127.20, 129.08, 129.44, 129.54,
129.80, 131.42, 133.81, 135.39, 151.54, 174.03, 183.04; HRMS (ESI-
TOF) calcd for C22H23ClN2O4S ([M þ Na]þ): 469.0965; found:
469.0963. 6’(a)(iv); syn isomer: Rf 0.37, EtOAcehexane, 1:3; white
Rf 0.34, EtOAcehexane, 3:7; yield 39%; white solid; mp
181e184 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.41 (s, 9H),1.48 (s, 3H), 5.72
solid; mp 158e160 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.43 (s, 9H), 1.76
(s, 3H), 5.75 (s,1H), 6.51e6.53 (m, 2H), 7.25e7.29 (m, 2H), 7.36e7.39
(m, 5H), 7.77 (brs, 1H, OH); 13C NMR (100 MHz, CDCl3)
20.19,
(s, 1H), 7.37e7.39 (m, 2H), 7.42e7.48 (m, 3H), 7.55e7.56 (m, 1H) 7.82
(d, J ¼ 8.4 Hz, 1H); 13C NMR (100 MHz, CDCl3)
d
19.62, 27.55, 67.07,
d
78.98, 84.16, 114.14, 115.21, 127.52, 128.53, 129.47, 130.06, 132.04,
134.26, 135.85, 137.34, 137.49, 151.31, 173.22, 181.62; HRMS (ESI-TOF)
calcd for C24H21ClF3N3O4S ([M þ Na]þ): 562.0791; found: 562.0778.
27.62, 68.24, 80.16, 83.81, 127.38, 128.61, 129.22, 129.42, 129.84,
131.44, 133.78, 135.18, 151.92, 172.88, 182.29; HRMS (ESI-TOF) calcd
for C22H23ClN2O4S ([M þ Na]þ): 469.0965; found: 469.0970.
4.5.15. 5-[(4-bromophenyl) hydroxy methyl]-3-(4-cyano-3-
trifluoromethylphenyl)-5-methyl-4-oxo-2-thioxoimidazolidine-1-
carboxylic acid tert-butyl ester 6(e)(iii)
4.6. General procedure for the synthesis of 3-(substituted phenyl)-
5-[(4-substituted phenyl) hydroxy methyl]-5-methyl-4-oxo-2-
thioxoimidazolidine 7
Rf 0.32, EtOAcehexane, 3:7; yield 45%; white solid; mp
198e201 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.38 (s, 9H), 1.49 (s, 3H),
5.70 (s,1H), 7.30e7.32 (m, 2H), 7.53e7.62 (m, 3H), 7.74 (d, J ¼ 8.0 Hz,
In a typical experiment, to a solution of 3-(substituted
1H), 7.82 (s, 1H), 7.99 (d, J ¼ 8.0 Hz, 1H); 13C NMR (100 MHz, CDCl3)
phenyl)-5-[(4-substituted phenyl) hydroxy methyl]-5-methyl-
4-oxo-2-thioxoimidazolidine-1-carboxylic acid tert-butyl ester
(0.32 mmol) in dichloromethane was added methanolic HCl
(2.5 mL, 1 M solution) and stirred for 12 h. The reaction mixture
was concentrated to provide a crude solid compound which was
purified by column chromatography on silica gel (60e120 mesh)
using a mixture of ethyl acetate and hexane as the eluent to
get the desired product. The products were characterized by
analytical and spectral methods.
d
19.60, 27.64, 67.01, 79.05, 84.15, 113.97, 115.20, 124.06, 127.52,
129.01, 130.06, 132.39, 132.59, 134.25, 136.63, 137.32, 137.47, 151.32,
173.22, 181.60; HRMS (ESI-TOF) calcd for C24H21BrF3N3O4S
([M þ Na]þ): 606.0286; found: 606.0283.
4.5.16. 5-[(4-fluorophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine-1-carboxylic
acid tert-butyl ester 6(f)(i)
Rf 0.32, EtOAcehexane, 3:7; yield 54%; white solid; mp
188e190 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 9H), 1.50 (s, 3H),
4.6.1. 3-(4-chlorophenyl)-5-[(4-fluorophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine 7(a)(i)
5.73 (s, 1H), 7.09 (brs, 1H, OH), 7.17e7.21 (m, 2H), 7.42e7.45 (m, 2H)
7.77e7.80 (m, 1H), 7.84e7.85 (m, 1H), 8.04 (d, J ¼ 8.5 Hz, 1H); 13C
Rf 0.60, EtOAcehexane, 2:3; yield 90%; white solid; mp
NMR (100 MHz, CDCl3)
d
19.82, 27.55, 67.07, 78.93, 84.07, 116.29,
172e174 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 3H), 2.47 (brs, 1H,
OH), 5.01 (s, 1H), 6.95 (brs,1H, NH), 7.13e7.17 (m, 2H), 7.25e7.34 (m,
2H), 7.40e7.48 (m, 4H); 13C NMR (100 MHz, CD3OD)
18.23, 68.36,
116.50,125.90,128.20,128.25,128.97,129.05,129.39,129.43,133.03,
136.38, 151.31, 173.17, 181.30; HRMS (ESI-TOF) calcd for
C23H21F4N3O6S ([M þ Na]þ): 566.0985; found: 566.0985.
d
75.76, 114.42, 128.51, 129.25, 129.94, 130.12, 132.22, 134.19, 134.84,
176.32, 182.91; HRMS (ESI-TOF) calcd for C17H14ClFN2O2S
([M þ Na]þ): 387.0347; found: 387.0348.
4.5.17. 5-[(4-chlorophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine-1-carboxylic
acid tert-butyl ester 6(f)(ii)
4.6.2. 3-(4-chlorophenyl)-5-[(4-chlorophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine 7(a)(ii)
Rf 0.32, EtOAcehexane, 3:7; yield 47%; white solid; mp
179e181 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 9H),1.51 (s, 3H), 5.71
Rf 0.60, EtOAcehexane, 2:3; yield 85%; white solid; mp
(s,1H), 7.19 (brs,1H, OH), 7.39 (d, J ¼ 8.4 Hz, 2H), 7.48 (d, J ¼ 8.4 Hz, 2H)
178e180 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 3H), 2.52 (brs, 1H,
OH), 5.02 (s, 1H), 6.96 (brs, 1H, NH), 7.25e7.30 (m, 2H), 7.37e7.39
(m, 2H), 7.43e7.49 (m, 4H); 13C NMR (100 MHz, CD3OD)
18.18,
7.77e7.80 (m,1H), 7.84e7.85 (m,1H), 8.05 (d, J ¼ 8.5 Hz,1H); 13C NMR
(100 MHz, CDCl3)
d
19.78, 27.55, 66.99, 78.93, 84.20, 125.95, 128.18,
d
128.24, 128.46, 128.68, 128.97, 129.53, 132.04, 133.06, 135.93, 136.32,
151.29, 173.12, 181.29; HRMS (ESI-TOF) calcd for C23H21ClF3N3O6S
([M þ Na]þ): 582.0689; found: 582.0695.
68.25, 75.93, 127.92, 128.50, 129.01, 129.93, 132.21, 133.87, 134.18,
137.63, 176.21, 182.92; HRMS (ESI-TOF) calcd for C17H14Cl2N2O2S
([M þ Na]þ): 403.0051; found: 403.0047.

G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
3299
4.6.3. 3-(4-chlorophenyl)-5-[(4-bromophenyl) hydroxy methyl]-5-
methyl-4-oxo-2-thioxoimidazolidine 7(a)(iii)
(m, 1H), 7.59e7.60 (m, 1H), 7.61e7.67 (m, 3H); 13C NMR (100 MHz,
CD3OD) 22.01, 72.38, 79.99, 125.08, 125.99, 131.62, 131.94, 132.26,
d
Rf 0.60, EtOAcehexane, 2:3; yield 95%; white solid; mp
133.23, 134.93, 135.68, 136.45, 137.38, 141.85, 179.72, 186.09; HRMS
(ESI-TOF) calcd for C18H13BrClF3N2O2S ([M þ Na]þ): 514.9420;
found: 514.9415.
186e188 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.38 (s, 3H), 2.57 (brs, 1H,
OH), 5.01 (s, 1H), 6.98 (brs, 1H, NH), 7.25e7.26 (m, 1H), 7.32e7.36
(m, 3H), 7.47e7.51 (m, 2H), 7.59e7.61 (m, 2H); 13C NMR (100 MHz,
CD3OD)
d
18.19, 68.22, 75.98, 121.93, 128.52, 129.32, 129.94, 130.95,
4.6.10. 2-chloro-4-[4-{(4-fluorophenyl) hydroxy methyl}-4-methyl-
5-oxo-2-thioxoimidazolidin-1-yl]benzonitrile 7(d)(i)
132.19, 134.19, 138.09, 176.18, 182.91; HRMS (ESI-TOF) calcd for
C17H14BrClN2O2S ([M þ Na]þ): 446.9546; found: 446.9541.
Rf 0.58, EtOAcehexane, 2:3; yield 65%; white solid; mp
178e181 ꢂC; 1H NMR (300 MHz, (CD3)2SO)
d
1.34 (s, 3H), 6.19
(s, 1H), 7.15e7.22 (m, 2H), 7.35e7.44 (m, 3H), 7.58 (s, 1H), 8.09e8.14
(m, 1H), 10.52 (brs, 1H, NH); 13C NMR (75 MHz, (CD3)2SO)
18.99,
4.6.4. 3-(3-chloro-4-fluorophenyl)-5-[(4-fluorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(b)(i)
d
Rf 0.64, EtOAcehexane, 2:3; yield 78%; white solid; mp
69.19, 75.52, 112.37, 114.92, 115.95, 128.82, 130.09, 130.17, 130.45,
135.26, 135.63, 135.67, 138.93, 175.39, 180.98; HRMS (ESI-TOF) calcd
for C18H13ClFN3O2S ([M þ Na]þ): 412.0299; found: 412.0295.
169e171 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 3H), 2.48 (brs, 1H,
OH), 5.04 (s,1H), 6.95 (brs,1H, NH), 7.15e7.19 (m, 2H), 7.21e7.25 (m,
2H), 7.40e7.45 (m, 3H); 13C NMR (100 MHz, CD3OD)
18.14, 68.46,
d
75.99, 114.45, 116.16, 120.44, 129.00, 129.25, 129.34, 130.19, 130.23,
130.81, 134.76, 176.16, 182.64; HRMS (ESI-TOF) calcd for
C17H13ClF2N2O2S ([M þ Na]þ): 405.0252; found: 405.0247.
4.6.11. 2-chloro-4-[4-{(4-chlorophenyl) hydroxy methyl}-4-methyl-
5-oxo-2-thioxoimidazolidin-1-yl]benzonitrile 7(d)(ii)
Rf 0.61, EtOAcehexane, 2:3; yield 73%; white solid; mp
179e181 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.41 (s, 3H), 2.52 (brs, 1H,
4.6.5. 3-(3-chloro-4-fluorophenyl)-5-[(4-chlorophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(b)(ii)
OH), 5.04 (s, 1H), 6.96 (brs, 1H, NH), 7.32e7.40 (m, 2H), 7.44e7.48 (m,
3H), 7.59e7.60(m,1H), 7.79e7.82 (m,1H);13C NMR(100 MHz, CD3OD)
Rf 0.64, EtOAcehexane, 2:3; yield 85%; white solid; mp
d 19.39, 69.97, 77.43, 114.02, 116.36, 129.21, 129.39, 130.42, 131.06,
175e178 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.40 (s, 3H), 2.56 (brs, 1H,
OH), 5.02 (s, 1H), 7.04 (brs, 1H, NH), 7.20e7.25 (m, 2H), 7.37e7.41
(m, 3H), 7.44e7.46 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.83,
131.34, 135.32, 137.36, 138.85, 139.90, 176.83, 183.01; HRMS (ESI-TOF)
calcd for C18H13Cl2N3O2S ([M þ Na]þ): 428.0004; found: 427.9992.
d
67.88, 76.16, 116.88, 117.10, 121.63, 128.45, 128.51, 129.26, 130.83,
135.50, 135.57, 157.08, 174.93, 183.07; HRMS (ESI-TOF) calcd for
C17H13Cl2FN2O2S ([M þ Na]þ): 420.9957; found: 420.9949.
4.6.12. 2-chloro-4-[4-{(4-bromophenyl) hydroxy methyl}-4-
methyl-5-oxo-2-thioxoimidazolidin-1-yl]benzonitrile 7(d)(iii)
Rf 0.61, EtOAcehexane, 2:3; yield 67%; white solid; mp
169e171 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.41 (s, 3H), 2.52 (brs, 1H,
4.6.6. 3-(3-chloro-4-fluorophenyl)-5-[(4-bromophenyl) hydroxy
methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(b)(iii)
OH), 5.02 (s, 1H), 6.98 (brs, 1H, NH), 7.32e7.34 (m, 2H), 7.43e7.46
(m, 1H), 7.52e7.54 (m, 1H), 7.59e7.63 (m, 2H), 7.79e7.81 (m, 1H);
Rf 0.64, EtOAcehexane, 2:3; yield 88%; white solid; mp
13C NMR (100 MHz, CD3OD)
d 19.40, 69.92, 77.48, 114.11, 116.37,
172e174 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 3H), 2.65 (brs, 1H,
OH), 4.99 (s, 1H), 7.13e7.27 (m, 2H), 7.29e7.33 (m, 2H), 7.38e7.39
(m, 1H), 7.58e7.60 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.84,
123.52, 129.79, 130.73, 132.36, 132.41, 135.41, 137.38, 139.42, 139.88,
176.81, 183.00; HRMS (ESI-TOF) calcd for C18H13BrClN3O2S
([M þ Na]þ): 471.9498; found: 471.9493.
d
67.95, 76.23, 116.91, 121.63, 123.59, 128.46, 129.06, 130.83, 132.19,
136.07, 157.08, 159.59, 175.03, 182.95; HRMS (ESI-TOF) calcd for
C17H13BrClFN2O2S ([M þ Na]þ): 464.9452; found: 464.9448.
4.6.13. 4-{4-[(4-fluorophenyl) hydroxy methyl]-4-methyl-5-oxo-2-
thioxoimidazolidin-1-yl}-2-trifluoromethyl benzonitrile 7(e)(i)
Rf 0.60, EtOAcehexane, 2:3; yield 58%; white solid; mp
4.6.7. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-fluorophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(c)(i)
Rf 0.71, EtOAcehexane, 2:3; yield 70%; white solid; mp
138e140 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.43 (s, 3H), 2.60 (brs, 1H,
OH), 5.06 (s, 1H), 6.95 (brs, 1H, NH), 7.06e7.22 (m, 3H), 7.38e7.57
(m,1H), 7.76e7.98 (m, 3H); 13C NMR (100 MHz, CDCl3)
19.81, 68.25,
d
158e160 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.39 (s, 3H), 2.54 (brs, 1H,
OH), 5.02 (s, 1H), 7.07 (brs, 1H, NH), 7.14e7.19 (m, 2H), 7.41e7.51
(m, 3H), 7.63e7.67 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.84,
76.26, 115.54, 116.07, 116.29, 126.91, 128.89, 128.97, 132.06, 132.78,
135.21, 135.33, 136.33, 136.84, 174.42, 181.62; HRMS (ESI-TOF) calcd
for C19H13F4N3O2S ([M þ Na]þ): 446.0562; found: 446.0562.
d
68.05, 76.19, 116.03, 116.24, 127.70, 127.76, 128.83, 128.91, 131.44,
132.18, 132.72, 132.88, 133.19, 174.80, 182.60; HRMS (ESI-TOF) calcd
for C18H13ClF4N2O2S ([M þ Na]þ): 455.0220; found: 455.0221.
4.6.14. 4-{4-[(4-chlorophenyl) hydroxy methyl]-4-methyl-5-oxo-2-
thioxoimidazolidin-1-yl}-2-trifluoromethyl benzonitrile 7(e)(ii)
Rf 0.60, EtOAcehexane, 2:3; yield 55%; white solid; mp
4.6.8. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-chlorophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(c)(ii)
Rf 0.75, EtOAcehexane, 2:3; yield 79%; white solid; mp
179e181 ꢂC; 1H NMR (400 MHz, CD3OD)
d
1.40 (s, 3H), 4.89 (s, 1H),
7.36e7.41 (m, 5H), 7.51e7.52 (d, J ¼ 1.8 Hz, 1H), 7.79 (d, J ¼ 8.3 Hz,
1H); 13C NMR (100 MHz, CD3OD)
23.03, 72.53, 79.91, 117.15,
d
179e181 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.41 (s, 3H), 2.63 (brs, 1H,
OH), 5.02 (s, 1H), 7.15 (brs, 1H, NH), 7.37e7.39 (m, 2H), 7.43e7.49
(m, 3H), 7.63e7.66 (m, 2H); 13C NMR (100 MHz, CDCl3)
19.80,
119.30, 131.38, 132.45, 132.68, 133.96, 137.95, 138.51, 140.54, 140.93,
141.72, 179.26, 185.57; HRMS (ESI-TOF) calcd for C19H13ClF3N3O2S
([M þ Na]þ): 462.0267; found: 462.0266.
d
68.03, 76.17, 120.87, 123.59, 127.73, 128.46, 129.13, 129.45, 131.39,
132.20, 132.72, 133.23, 133.50, 174.77, 182.57; HRMS (ESI-TOF) calcd
for C18H13Cl2F3N2O2S ([M þ Na]þ): 470.9925; found: 470.9925.
4.6.15. 4-{4-[(4-bromophenyl) hydroxy methyl]-4-methyl-5-oxo-2-
thioxoimidazolidin-1-yl}-2-trifluoromethyl benzonitrile 7(e)(iii)
Rf 0.60, EtOAcehexane, 2:3; yield 62%; white solid; mp
4.6.9. 3-(4-chloro-3-trifluoromethylphenyl)-5-[(4-bromophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine 7(c)(iii)
Rf 0.75, EtOAcehexane, 2:3; yield 74%; white solid; mp
152e154 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.43 (s, 3H), 2.64 (brs, 1H,
OH), 5.03 (s, 1H), 7.20 (brs, 1H, NH), 7.32e7.43 (m, 2H), 7.60e7.62
(m, 2H), 7.75e7.78 (m, 1H), 7.83e7.86 (m, 1H), 7.91e7.98 (m, 1H);
162e165 ꢂC; 1H NMR (400 MHz, CDCl3)
d
1.42 (s, 3H), 2.58 (brs, 1H,
13C NMR (100 MHz, CDCl3)
d
19.79, 68.09, 76.32, 110.29, 114.78,
OH), 5.02 (s, 1H), 7.03 (brs, 1H, NH), 7.32e7.34 (m, 2H), 7.47e7.51
123.80, 126.83, 128.85, 131.80, 132.04, 132.30, 133.86, 135.23, 135.87,

3300
G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
136.78, 174.30, 181.59; HRMS (ESI-TOF) calcd for C19H13BrF3N3O2S
4.7.2. (R)-[(S)-(4-Chlorophenyl){(R)-1-(4-chlorophenyl)-4-methyl-
5-oxo-2-thioxoimidazolidin-4-yl}methyl]-2-methoxy-2-
phenylacetate 9’(a)(ii)
([M þ H]þ): 483.9942; found: 483.9941.
4.6.16. 5-[(4-fluorophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine 7(f)(i)
Rf 0.61, EtOAcehexane, 2:3; yield 50%; white solid; mp
Rf 0.52, EtOAcehexane, 2:3; ½a D20
ꢄ
þ 45ꢂ (c 1.00, CHCl3); white
solid; mp 89e92 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.391 (s, 3H, CH3),
3.373 (s, 3H, OCH3), 4.756 (s, 1H, MPA), 5.833 (s, 1H, sec. alcohol),
6.76e6.79 (m, 2H), 7.043 (brs, 1H, NH), 7.15e7.22 (m, 2H), 7.18e7.21
(m, 2H), 7.32e7.34 (m, 2H) 7.35e7.43 (m, 3H), 7.47e7.51 (m, 2H);
158e160 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.43 (s, 3H), 2.43 (brs, 1H,
OH), 5.07 (s, 1H), 6.99 (brs, 1H, NH), 7.17e7.21 (m, 2H), 7.43e7.46
(m, 2H), 7.80e7.82 (m, 1H), 7.90e7.93 (m, 1H), 8.02e8.05 (m, 1H);
13C NMR (100 MHz, CD3OD)
d 21.95, 60.33, 70.31, 81.26, 85.81,
13C NMR (100 MHz, CDCl3)
d
19.83, 68.13, 76.27, 116.17, 116.38,
131.26, 131.99, 132.39, 132.60, 132.64, 132.67, 133.76, 135.73, 136.30,
138.35, 138.58, 139.60, 172.71, 178.47, 186.66; HRMS (ESI-TOF) calcd
for C26H22Cl2N2O4S ([M þ Na]þ): 551.0575; found: 551.0580.
125.85, 128.14,128.84, 128.92, 132.69, 132.83, 136.42, 174.34, 181.65;
HRMS (ESI-TOF) calcd for C18H13F4N3O2S ([M þ Na]þ): 466.0461;
found: 466.0447.
4.8. X-ray crystallographic data
4.6.17. 5-[(4-chlorophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine 7(f)(ii)
Rf 0.60, EtOAcehexane, 2:3; yield 60%; white solid; mp
Both diastereomers 9(a)(ii) and 9’(a)(ii) were subjected to
crystallization, crystals were formed only from diastereomer 9(a)(ii)
(DCM: Hexane ¼ 1:2, v/v) and a single crystal with dimension
0.35 ꢅ 0.23 ꢅ 0.20 mm was mounted and used for data collection.
The intensity data were collected; and the lattice parameters and
standard deviations were obtained. The data were corrected for
Lorentz and polarization factors. The structure was solved by Direct
Methods using SHELX-97 [40] package and also refined using the
same. Crystallographic data for the compound 9(a)(ii) has been
deposited with the Cambridge Crystallographic Data Centre, CCDC
No. 733607. Copies of the data can be obtained, free of charge, on
application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK,
(Fax: þ44 1223 336033 or e-mail: deposit@ccdc.cam.ac.uk).
148e150 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.39 (s, 3H), 2.60 (brs, 1H,
OH), 5.05 (s,1H), 7.11 (brs,1H, NH), 7.39e7.47 (m, 4H), 7.79e7.81 (m,
1H), 7.87e7.89 (m, 1H), 8.03 (d, J ¼ 8.0 Hz, 1H); 13C NMR (100 MHz,
CD3OD)
d 17.95, 68.93, 76.05, 125.53, 127.74, 127.87, 127.92, 127.99,
129.00, 133.53, 134.03, 137.17, 137.37, 147.06, 175.41, 181.47; HRMS
(ESI-TOF) calcd for C18H13ClF3N3O2S ([M þ H]þ): 460.0345; found:
460.0340.
4.6.18. 5-[(4-bromophenyl) hydroxy methyl]-5-methyl-3-(4-nitro-
3-trifluoromethylphenyl)-4-oxo-2-thioxoimidazolidine 7(f)(iii)
Rf 0.60, EtOAcehexane, 2:3; yield 57%; white solid; mp
108e110 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.43 (s, 3H), 2.62 (brs, 1H,
OH), 5.03 (s, 1H), 7.14 (brs, 1H, NH), 7.33 (d, J ¼ 8.2 Hz, 2H),
4.9. In-vitro cytotoxicity evaluation
7.58e7.63 (m, 2H), 7.79e7.81 (m, 1H), 7.88e7.89 (m, 1H), 8.03 (d,
J ¼ 8.2 Hz, 1H); 13C NMR (100 MHz, CDCl3)
d
19.75, 68.08, 76.31,
4.9.1. Cell lines and cell culture
125.74, 125.85, 128.05, 128.11, 128.73, 128.78, 131.84, 132.31, 132.83,
135.84, 136.38, 174.31, 181.64; HRMS (ESI-TOF) calcd for
C18H13BrF3N3O2S ([M þ Na]þ): 525.9660; found: 525.9641.
Human prostate carcinoma cells, PC-3 and LNCaP, were obtained
from National Centre for Cell Science (NCCS), India. The cells were
cultured in DMEM and RPMI1640 respectively, containing 10% FBS
and 1% penicillin-streptomycin. DMEM, RPMI1640, FBS, flutamide
and doxorubicin were obtained from Sigma. MTT was obtained
from Hi-Media. Cell cultures were maintained in flasks under
standard conditions: incubation at 37 ꢂC and 5% CO2. All the
subcultures were used prior to passage 15. Cells were routinely
passaged using 0.25% trypsin/0.1% EDTA. For treatment, cells were
cultured in the presence of increasing concentrations (10ꢃ12 M,
10ꢃ10 M, 10ꢃ8 M, 10ꢃ6 M and 10ꢃ4 M) of compounds for 24 h.
4.7. Synthesis of (R)-MPA ester 9
To
a
solution of 3-(4-chlorophenyl)-5-[(4-chlorophenyl)
hydroxy methyl]-5-methyl-4-oxo-2-thioxoimidazolidine (0.06 g,
0.16 mmol) in DCM (5 mL), (R)-MPA (0.026 g, 0.16 mmol), DMAP
(0.3 g, 0.17 mmol) and EDC.HCl (0.2 g, 0.17 mmol) were added. The
reaction mixture was stirred at room temperature for 1 h, then
washed with dilute HCl and the organic layer dried over anhydrous
sodium sulphate was concentrated to afford the (R)-MPA ester of
7(a)(ii) (white solid, 0.083 g, 70%, mixture of diastereomers). The
diastereomers obtained were separated by preparative thin layer
chromatography using a mixture of ethyl acetate and hexane (3:7)
as the eluent. The products were characterized by analytical and
spectral methods.
4.9.2. In-vitro cytotoxicity measurements
All in-vitro experiments for cell proliferation/inhibition were
performed in triplicates. PC-3 cells were originally derived from
advanced androgen independent bone metastasized prostate
cancer [41]. For the PC-3 cell growth inhibition assay, cells were
cultured in DMEM supplement and trypsinized, further diluted to
2.0 ꢅ 104 cell/mL with DMEM supplemented with 10% fetal bovine
serum. This cell suspension was transferred to 96-well microtiter
plates, and incubated in the presence or absence of increasing
concentration of positive control (doxorubicin) or the test
compounds (10ꢃ12 M, 10ꢃ10 M, 10ꢃ8 M, 10ꢃ6 M and 10ꢃ4 M) at 37 ꢂC
and 5% CO2 [42]. After 24 h incubation, cells were treated with MTT
solution for 4h in a cell culture incubator at 37 ꢂC and 5% CO2. Cell
proliferation was determined by the MTT method [43,44]. MTT
which is a tetrazolium salt is converted into insoluble formazan by
mitochondrial dehydrogenases in live cells. Formazan is dissolved
in DMSO (Merck) and absorbance was measured at dual wave-
length of 550 nm and 630 nm on an ELISA plate spectrophotometer
(Biotrek Instruments). Similar experiments were performed in
LNCaP cells also. Since LNCaP cells have demonstrated androgen
dependent cell growth [41]; promotion and inhibition of cell
4.7.1. (R)-[(R)-(4-chlorophenyl){(S)-1-(4-chlorophenyl)-4-methyl-
5-oxo-2-thioxoimidazolidin-4-yl}methyl]-2-methoxy-2-
phenylacetate 9(a)(ii)
Rf 0.61, EtOAcehexane, 2:3; ½a D20
ꢄ
ꢃ 88ꢂ (c 1.00, CHCl3); white
solid; mp 206e208 ꢂC; 1H NMR (400 MHz, CDCl3)
d 1.341 (s, 3H,
CH3), 3.304 (s, 3H, OCH3), 4.782 (s, 1H, MPA), 5.808 (s, 1H, sec.
alcohol), 6.98e7.00 (m, 2H), 7.088 (brs, 1H, NH), 7.11e7.15 (m, 2H),
7.24e7.26 (m, 2H), 7.36e7.45 (m, 7H); 13C NMR (100 MHz,
(CD3)2SO)
d 19.98, 58.13, 67.53, 77.86, 83.27, 128.49, 129.44, 129.86,
130.03, 130.16, 130.39, 131.64, 133.10, 134.38, 134.66, 134.82, 136.81,
169.86, 175.07, 183.24; HRMS (ESI-TOF) calcd for C26H22Cl2N2O4S
([M þ Na]þ): 551.0575; found: 551.0578.

G.L. Khatik et al. / European Journal of Medicinal Chemistry 46 (2011) 3291e3301
3301
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growth was considered as agonistic and antagonistic respectively.
These cells are known to possess an aberrant AR with a mutation of
877Thr to Ala. LNCaP cells were cultured as described above in
RPMI1640 media and were transferred into a 96-well plate with
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Funding for this research work from the Department of Science
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