Synthesis and antiproliferative evaluation of 2'-arenesulfonyloxy-5- benzylidene-thiazolidine-2,4-diones

Article abstract of DOI:10.1002/jhet.859

A series of 2'-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones (TZDs) were synthesized and examined for their antiproliferative effects on a panel of carcinoma cell lines. Our results indicated that initial synthesis of 5-[2'-hydroxybenzylidene]-2,

Full text of DOI:10.1002/jhet.859

792
Synthesis and Antiproliferative Evaluation of
Vol 49
20-Arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones
Emily M. Chen,a Pei-Jung Lu,b and Arthur Y. Shawc,d
*
aDepartment of Chemistry, Tamkang University, Danshui 251, Taiwan
bInstitute of Clinical Medicine, National Cheng Kung University, Tainan 701, Taiwan
cDepartment of Pharmacology and Toxicology, College of Pharmacy,
University of Arizona, Tucson, Arizona 85721
dThe Southwest Comprehensive Center for Drug Discovery and Development, 1580 E. Hanley Blvd.,
Oro Valley, Arizona 85737
*
E-mail: shaw@pharmacy.arizona.edu
Received November 13, 2010
DOI 10.1002/jhet.859
View this article online at wileyonlinelibrary.com.
O O
S
O
Ar
O
O
HN
O
HN
S
S
O
1
8a-8p
A series of 20-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones (TZDs) were synthesized and
examined for their antiproliferative effects on a panel of carcinoma cell lines. Our results indicated that initial
synthesis of 5-[20-hydroxybenzylidene]-2,4-thiazolidinone (9) by Knoevenagel condensation followed by
nucleophilic substitution with arylsulfonyl chlorides exhibited superior efficiency to the alternative synthetic
route. Among tested compounds, only 8c and 8e showed significant antiproliferative activity against PC-3 and
BT474 cells with GI50 values of 8.4 and 20.6 mM, respectively. SKHep cells displayed interesting structure-
activity relationships in response to TZD derivatives treatment. Alkyl group-substituted TZD analogs such as
8a (4-Me, GI50, 9.4 mM) and 8k (4-iso-propyl, GI50, 9.8 mM) revealed better antiproliferative activity than
those with bulkier alkyl groups. On the other hand, halogen-substituted TZD analogs 8c, 8h, and 8i showed
better antiproliferative activity against H460 cell line. Together, the new synthesized TZD derivatives 8a-8p
exhibited appreciable antiproliferative activity worth for further study.
J. Heterocyclic Chem., 49, 792 (2012).
INTRODUCTION
5a-f with 2-hydroxybenzaldehyde (6) in the presence of
triethylamine in dichloromethane was carried out to afford
arylsulfonates 7a-f with good yields of 83–94% [13]. Aryl-
sulfonates 7a-f were subjected to undergo Knoevenagel
condensation with thiazolidinone (1) in the presence of
0.5 equiv of piperidine in refluxed ethanol for 18–22 hr that
afforded compounds 8a-f with moderate yields of 43–56%.
Accordingly, Knoevenagel condensation was poor in either
strong bases such as sodium hydride and triethylamine or
any bases more than 0.5 equiv. Moreover, the condensation
reaction would not occur if no heat was charged.
We further turned our attention to employ the Method B
in which the 5-[20-hydroxybenzylidene]-2,4-thiazolidinone
(9) was initially prepared as indicated in Scheme 1 [14].
Knoevenagel condensation of 2-hydroxybenzaldehyde 6
was expediently completed in the presence of sodium
acetate in thiazolidinone 1 solution at 120ꢀC in 10 min to
give 9 with 85% isolated yield. With the intermediate 9
in hand, nucleophilic substitution of 9 with arylsulfonyl
chlorides 5g-p was taken place in the presence of triethyla-
mine in acetone to give final products 8g-p with moderate
yields of 52–69%. Compared to Method A, Method B
demonstrated to be more efficient in terms of time and
overall yield (Table 1).
Thiazolidinone (TZD) derivatives are reported to exhibit a
variety of pharmacological activities such as antidiabetic [1],
antioxidant [2], anti-inflammatory [3], antimicrobial [4],
antiproliferative [5,6], antiviral [7], anticonvulsant [8], anti-
fungal [9,10], and antibacterial activities [11]. In regard to
its structural accessibility, TZD scaffold 1 can be modified
to expand their diverse corresponding derivatives 2-4
(Fig. 1) [12]. Among all biological activities, the anticancer
activity is of particular interest to us that we attempted to syn-
thesize a new series of 20-arenesulfonyloxy-5-benzylidene-
thiazolidine-2,4-diones. To the best of our knowledge, the
antiproliferative activity of above-mentioned TZD derivatives
has not yet been examined. Herein, we employed two
synthetic routes to prepare TZD derivatives by incorporating
20-arylsulfonyloxy groups as well as to evaluate their antipro-
liferative effect on a panel of carcinoma cell lines.
RESULTS AND DISCUSSION
To prepare a series of 20-arenesulfonyloxy-5-benzylidene-
thiazolidine-2,4-diones, two synthetic pathways were
utilized in the present work as shown in Scheme 1. As in-
dicated, nucleophilic substitution of arylsulfonyl chlorides
© 2012 HeteroCorporation

July 2012
Synthesis and Antiproliferative Evaluation of 20-Arenesulfonyloxy-5-benzylidene-
thiazolidine-2,4-diones
793
SKHep cells to the tested compounds exhibited interesting
structure-activity relationships. For instance, compared to
8b (GI50, 9.8 mM) without any substituents at 4-position,
alkyl group-substituted analogs showed that methyl (8a,
GI50, 9.4 mM) and isopropyl (8k, GI50, 9.8 mM) groups
displayed better antiproliferative activity while the potency
was counteracted as the bulky groups such as t-butyl (8l,
GI50, 15.7 mM) and phenyl (8n, GI50, 23.1 mM) groups
were introduced. Moreover, we found that neither electron-
donating groups (8f, 3-OMe; 8g, 4-OMe and 8j, 3,4-di-OMe)
nor electron-withdrawing groups (8c, 4-Cl; 8d, 4-NO2; 8h,
4-F; 8i, 4-Br and 8m, 4-OCF3) at 3- and/or 4-position
showed any antiproliferative activity against SKHep cells
at maximal concentration treatment. Interestingly, 8e bearing
2-nitro group exhibited the most potent activity among all
tested compounds with a GI50 value of 8.7 mM against SKHep
cells. In addition, replacement of benzene ring 8b (GI50,
9.8 mM) with naphthalene moiety (8o and 8p) resulted in the
loss of antiproliferative activity. As regard to the sensitivity
of H460 cells in response to the compound treatment, we
found that halogen-substituted analogs 8c (4-Cl), 8h (4-F),
and 8i (4-Br) exhibited better activity than others with GI50
values of 8.7, 16.5, and 18.9 mM, respectively. Except for 8a
(4-Me) without activity, analogs containing alky groups did
not show substantial structure-activity relationships between
8k (4-iso-propyl, GI50, 22.3 mM), 8l (4-tert-butyl, GI50,
27.2 mM) and 8n (4-biphenyl, GI50, 18.9 mM).
Figure 1. Thiazolidine-2,4-dione (1) and its derivatives 2-4.
The antiproliferative evaluation of newly synthesized
20-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones
8a-p was examined on a panel of five human carcinoma
cell lines, including PC-3 (prostate carcinoma cell), H460
(lung large cell adenocarcinoma cell), SW620 (colorectal
adenocarcinoma cell), BT474 (breast carcinoma cell) and
SKHep (hepatocellular carcinoma cell). The MTT (3-
[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide)
assay was utilized for these antiproliferation studies and
the GI50 values are summarized in Table 2 [15]. The com-
pound concentration causing a 50% cell growth inhibition
(GI50) was determined by interpolation from dose-response
curves. The maximal concentration of tested compounds
was treated with 40 mM to all cell lines due to the solubility
of tested compounds in the Dulbecco’s modified eagle
medium (DMEM).
As shown in Table 2, none of the tested compounds
exhibited antiproliferative effect against SW620 cells.
On the other hand, only 8c and 8e showed significant
antiproliferative activity against PC-3 and BT474 cells
with GI50 values of 8.4 and 20.6 mM, respectively. Never-
theless, both SKHep and H460 cells displayed appreciable
sensitivity in response to TZD treatment. Exposure of
MATERIALS AND METHODS
Synthesis. Chemical reagents and organic solvents were
purchased from TCI, Acros, Aldrich and Alfa Aesar unless
otherwise mentioned. Melting points were determined by Fargo
MP-2D. Nuclear magnetic resonance spectra (1H and 13C NMR)
were measured on a Bruker AC-300 instrument. Chemical shifts
(d) are reported in ppm relative to the TMS peak. High resolution
mass spectra (HRMS) were obtained by FAB on a Jeol JMS-700
instrument. Flash column chromatography was performed with
Scheme 1. Reagents and conditions: (a) 2-hydroxybenzaldehyde (6), DCM, TEA, r.t, 2–3 hr; (b) 1, EtOH, piperidine, ref lux, 18–22 hr; (c) 1, NaOAc,
120–140ꢀC, 10 min; (d) arylsulfonyl chlorides 5g-p, acetone, TEA, r.t, 18–22 hr.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

794
E. M. Chen, P.-J. Lu, and A. Y. Shaw
Vol 49
Table 1
Synthesis of 20-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones 8a–p.
Table 1
(Continued)
Entry
1
Structure
Yield (%)a
39
EntrEyntry
Structure
Yield (%)a
8a
8b
8c
8d
8e
8f
12
8l
57
54
57
58
58
2
44
46
46
45
48
44
47
46
49
53
13
14
15
8m
8n
8o
8p
3
4
16
5
aTwo-step isolated yield.
6
silica gel (230–400 mesh). Elemental analysis was carried out on a
Heraeus Vario EL-III C, H, N analyzer.
General procedure. 2-Formylphenyl 4-methylbenzenesulfonate
(7a). To a solution of 4-toluenesulfonyl chloride (0.59 g, 3.12
mmol) in dry dichloromethane (10 mL), 2-hydroxybenzaldehyde
(0.38 g, 3.12 mmol) and triethylamine (0.35 g, 3.43 mmol) were
added to the solution. The resulting mixture was stirred at room
temperature for 2 hr. The reaction solution was extracted with
water (20 mL) and brine (20 mL). The organic layer was dried
over anhydrous MgSO4. After filtration, solvent was removed
under reduced pressure and the crude residue was purified by
flash chromatography (hexane/ethyl acetate: 8/2) to afford 7a
(0.76 g, 88%). M.p 62.8ꢀC. 1H NMR (300 MHz, CDCl3) d
2.45(s, 3H), 7.19(d, J = 8.0Hz, 1H), 7.32(d, J = 8.3 Hz, 2H),
7.39(dd, J = 7.5, 7.6 Hz, 1H), 7.58(dd, J = 7.6, 8.0 Hz, 1H), 7.70
(d, J = 8.3 Hz, 2H), 7.85(d, J = 7.5 Hz, 1H), 9.99(s, 1H) ppm 13C
NMR (75 MHz, CDCl3) ꢀ 21.93, 123.90, 127.70, 128.68, 128.83,
129.49, 130.31, 131.58, 135.48, 146.50, 151.41, 187.49 ppm.
2-Formylphenyl benzenesulfonate (7b). Compound 7b was
synthesized from the procedure described for Compound 7a.
Yield: 92%. M.p 54.8ꢀC. H NMR (300 MHz, CDCl3) d 7.19
(d, J = 7.9 Hz, 1H), 7.42(dd, J = 7.5, 7.7 Hz, 1H), 7.56(dd,
J = 7.3, 7.5 Hz, 2H), 7.57(dd, J = 7.7, 7.9 Hz, 1H), 7.70(t,
J = 7.5 Hz, 1H), 7.85(d, J = 7.3 Hz, 2H), 7.88(d, J = 7.5
Hz, 1H), 9.99(s, 1H) ppm. 13C NMR (75 MHz, CDCl3) d
123.83, 127.81, 128.64, 128.94, 129.47, 129.71, 134.60, 135.12,
135.50, 151.24, 187.35 ppm.
7
8g
8h
8i
8
9
10
11
8j
1
8k
2-Formylphenyl 4-chlorobenzenesulfonate (7c). Compound 7c
was synthesized from the procedure described for Compound 7a.
(Continued)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2012
Synthesis and Antiproliferative Evaluation of 20-Arenesulfonyloxy-5-benzylidene-
thiazolidine-2,4-diones
795
Table 2
Antiproliferative evaluation of 20-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones 8a-p against carcinoma cells.
GI50 (mM)a
No.
SKHep
H460
SW620
BT474
PC-3
8a
8b
8c
8d
8e
8f
8g
8h
8i
8j
8k
8l
8m
8n
8o
8p
9.4 ꢁ 2.7
12.3 ꢁ 2.6
>40
>40
21.9 ꢁ 2.9
8.7 ꢁ 1.2
17.9 ꢁ 2.9
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
8.4 ꢁ 0.8
>40
>40
>40
8.7 ꢁ 0.9
20.6 ꢁ 2.9
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
>40
16.5 ꢁ 3.3
18.9 ꢁ 4.1
>40
22.3 ꢁ 2.6
27.2 ꢁ 4.3
>40
9.8 ꢁ 1.3
15.7 ꢁ 1.5
>40
23.1 ꢁ 2.2
18.9 ꢁ 3.8
>40
>40
>40
>40
>40
>40
aGI50 values are presented as the mean ꢁ SEM (standard error of the mean) from three separated experiments.
Yield: 94%. M.p 53.2ꢀC. 1H NMR (300 MHz, CDCl3) d 7.18 (d,
J = 7.6 Hz, 1H), 7.45(dd, J = 7.2, 7.7 Hz, 1H), 7.53(d, J = 6.8 Hz,
2H), 7.62(dd, J = 7.2, 7.6 Hz, 1H), 7.79(d, J = 6.8 Hz, 2H), 7.90
(d, J = 7.7 Hz, 1H), 10.07(s, 1H) ppm. 13C NMR (75 MHz,
CDCl3) d 123.69, 128.03, 129.39, 129.45, 130.10, 133.43,
135.60, 142.06, 151.41, 187.33 ppm.
mmol) and piperidine, (0.11 g, 1.3 mmol) in dry ethanol (8 mL),
the resulting mixture was stirred under reflux for 30 min, followed
by the addition of 2-formylphenyl 4-methylbenzenesulfonate (7a ,
0.75 g, 2.7 mmol) to stir for another 18 hr. The reaction solution
was evaporated in vacuo and the crude product was purified by
flash chromatography (hexane/ethyl acetate: 9/1 to 1/1) to afford
Compound 8a (0.46 g, 45 %). M.p 198.6ꢀC.
2-Formylphenyl 4-nitrobenzenesulfonate (7d). Compound 7d
was synthesized from the procedure described for Compound
1H NMR (300 MHz, DMSO-d6) d 2.33(s, 3H), 7.29(s, 1H),
7.35(dd, J = 7.9, 8.0 Hz, 1H), 7.36(d, J = 8.1 Hz, 2H), 7.41(d,
J = 7.0 Hz, 1H), 7.48(dd, J = 7.0, 7.9 Hz, 1H), 7.55(d, J = 8.1
Hz, 2H), 7.57(d, J = 8.0 Hz, 1H) ppm. 13C NMR (75 MHz,
DMSO-d6) d 21.06, 124.08, 124.60, 126.70, 127.10, 128.20,
128.34, 128.40, 130.47, 130.47, 130.65, 131.87, 146.13,
166.50, 167.73 ppm. HRMS (M+1)+ calcd for C17H14NO5S2
376.0313, found 376.0315. Anal. calcd. for C17H13NO5S2: C,
54.39; H, 3.49; N, 3.73. Found: C, 54.32; H, 3.54; N, 3.68.
(Z)-20-Benzenesulfonyloxy-5-benzylidene-thiazolidine-2,4-dione
(8b). Compound 8b was synthesized from the procedure described
for Compound 8a. Yield: 48 %. M.p 224.5ꢀC. 1H NMR (300
MHz, DMSO-d6) d 7.30(d, J = 8.1 Hz, 1H), 7.39(s, 1H), 7.47(dd,
J = 7.7, 8.4 Hz, 1H), 7.55(dd, J = 8.1, 8.4 Hz, 1H), 7.60(d, J = 7.7
Hz, 1H), 7.61(dd, J = 7.0, 7.2 Hz, 2H), 7.75(d, J = 7.2 Hz, 2H),
7.76(t, J = 7.0 Hz, 1H) ppm.13C NMR (75 MHz, DMSO-d6) d
123.80, 124.28, 126.76, 126.99, 128.15, 128.38, 128.54, 130.00,
131.89, 133.76, 135.18, 147.50, 166.63, 167.54 ppm. HRMS
(M+1)+ calcd for C16H12NO5S2 362.0157, found 362.0158. Anal.
calcd. for C16H11NO5S2: C, 53.18; H, 3.07; N, 3.88. Found: C,
53.23; H, 2.98; N, 3.78.
1
7a. Yield: 83%. M.p 121.3ꢀC. H NMR (300 MHz, CDCl3) d
7.20(d, J = 7.8 Hz, 1H), 7.47(dd, J = 6.3, 7.7 Hz, 1H), 7.62(dd,
J = 6.3, 7.8 Hz, 1H), 7.91(d, J = 7.7 Hz, 1H), 8.11(d, J = 8.9
Hz, 2H), 8.41(d, J = 8.9 Hz, 2H), 10.07(s, 1H) ppm. 13C NMR
(75 MHz, CDCl3) d 123.54, 124.83, 128.41, 129.34, 130.19,
135.74, 140.47, 150.26, 151.52, 187.11 ppm.
2-Formylphenyl 2-nitrobenzenesulfonate (7e). Compound 7e
was synthesized from the procedure described for Compound
1
7a. Yield: 85%. M.p 102.6ꢀC. H NMR (300 MHz, CDCl3) d
7.34(d, J = 8.1 Hz, 1H), 7.47(dd, J = 6.1, 7.1 Hz, 1H), 7.61(dd,
J = 6.1, 8.1 Hz, 1H), 7.74(m, 1H), 7.89(d, J = 7.1 Hz, 1H),
7.93(m, 3H), 10.23(s, 1H) ppm.13C NMR (75MHz, CDCl3) d
123.82, 125.40, 128.01, 128.32, 129.38, 132.19, 132.60,
135.73, 136.30, 148.90, 150.66, 187.80 ppm.
2-Formylphenyl 3-methoxybenzenesulfonate (7f). Compound
7f was synthesized from the procedure described for Compound
7a. Yield: 94%. M.p 50.6ꢀC. 1H NMR (300 MHz, CDCl3) d
3.79(s, 3H), 7.18(d, J = 8.1 Hz, 1H), 7.20(dd, J = 7.2, 7.6 Hz,
1H), 7.28(s, 1H), 7.40(m, 3H), 7.57(dd, J = 7.2, 8.1 Hz, 1H),
7.86(d, J = 7.6 Hz, 1H), 10.00(s, 1H) ppm.13C NMR (75 MHz,
CDCl3) d 55.46, 112.87, 120.23, 120.95, 123.33, 127.47, 128.46,
129.13, 130.42, 135.03, 135.15, 150.71, 159.85, 186.96 ppm.
(Z)-20-(4-Methylbenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8a). To a solution of 2,4-thiazolidinedione (0.32 g, 2.7
(Z)-20-(4-Chlorobenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8c). Compound 8c was synthesized from the procedure
described for Compound 8a. Yield: 43 %. M.p 187.7ꢀC. 1H NMR
(300 MHz, DMSO-d6) d 7.24(s, 1H), 7.38(d, J = 7.9 Hz, 1H), 7.46
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

796
E. M. Chen, P.-J. Lu, and A. Y. Shaw
Vol 49
(dd, J = 7.7, 8.0 Hz, 1H), 7.52(dd, J = 7.7, 7.9 Hz, 1H), 7.57(d, J =
8.0 Hz, 1H), 7.64(d, J = 8.8 Hz, 2H), 7.70(d, J = 8.8 Hz, 2H) ppm.
13C NMR (75 MHz, DMSO-d6) d 123.95, 124.16, 127.02, 127.18,
128.47, 128.55, 130.04, 130.28, 131.91, 132.20, 140.57, 147.33,
166.84, 167.65 ppm. HRMS (M+1)+ calcd for C16H11ClNO5S2
395.9767, found 395.9738. Anal. calcd. for C16H10ClNO5S2: C,
48.55; H, 2.55; N, 3.54. Found: C, 48.59; H, 2.46; N, 3.59.
(Z)-20-(4-Nitrobenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8d). Compound 8d was synthesized from the procedure
described for Compound 8a. Yield: 56 %. M.p 213.7ꢀC. 1H NMR
(300 MHz, DMSO-d6) d 7.12(s, 1H), 7.28(m, 1H), 7.47(m, 3H),
8.02(d, J = 8.8 Hz, 2H), 8.36(d, J = 8.8 Hz, 2H) ppm. 13C NMR
(75 MHz, DMSO-d6) d 119.04, 123.60, 125.06, 128.33, 128.47,
128.54, 129.99, 130.66, 133.51, 139.16, 147.05, 150.87, 171.03,
174.20 ppm. HRMS (M+1)+ calcd for C16H11N2O7S2 407.0008,
found 407.3997. Anal. calcd. for C16H10N2O7S2: C, 47.29; H,
2.48; N, 6.89. Found: C, 47.36; H, 2.53; N, 6.78.
(Z)-20-(2-Nitrobenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8e). Compound 8e was synthesized from the procedure
described for Compound 8a. Yield: 53 %. M.p 184.7ꢀC. 1H NMR
(300 MHz, DMSO-d6) d 7.38(m, 1H), 7.56(m, 4H), 7.83(d, J =
8.2 Hz, 1H), 7.84(dd, J = 7.9, 8.5 Hz, 1H), 8.01(dd, J = 8.2,
8.5 Hz, 1H), 8.11(d, J = 7.9 Hz, 1H) ppm. 13C NMR (75 MHz,
DMSO-d6) d 123.71, 124.28, 125.97, 126.26, 127.09, 127.71,
128.65, 128.80, 131.55, 131.94, 133.46, 136.89, 147.45, 147.59,
167.10, 167.68 ppm. HRMS (M+1)+ calcd for C16H11N2O7S2
407.0008, found 407.0005. Anal. calcd. for C16H10N2O7S2: C,
47.29; H, 2.48; N, 6.89. Found: C, 47.25; H, 2.52; N, 6.83.
(Z)-20-(3-Methoxybenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8f). Compound 8f was synthesized from the procedure de-
scribed for Compound 8a. Yield: 51 %. M.p 136.4ꢀC. 1H NMR (300
MHz, DMSO-d6) d 3.76(s, 3H), 7.15(s, 1H), 7.20(d, J = 7.8 Hz, 1H),
7.27(d, J = 8.0 Hz, 1H), 7.32(s, 1H), 7.38(d, J = 8.1 Hz, 1H), 7.42
(dd, J = 7.7, 7.9 Hz, 1H), 7.46(d, J = 7.9 Hz, 1H), 7.49(dd, J =
8.0, 8.1 Hz, 1H), 7.57(dd, J = 7.7, 7.8 Hz, 1H) ppm.13C NMR (75
MHz, DMSO-d6) d 55.67, 112.13, 120.35, 121.41, 123.99, 124.29,
126.57, 127.03, 128.37, 131.13, 131.89, 134.67, 147.49, 159.85,
166.51, 167.54 ppm. HRMS (M+1)+ calcd for C17H14NO6S2
392.0263, found 392.0262. Anal. calcd. for C17H13NO6S2: C,
52.16; H, 3.35; N, 3.58. Found: C, 52.15; H, 3.39; N, 3.49.
thiazolidine-2,4-dione (9, 0.30 g, 1.36 mmol) and 4-methoxyben-
zenesulfonyl chloride (0.31 g, 1.5 mmol) was dissolved in dry
acetone (10 mL), triethylamine (0.27 g, 2.72 mmol) was added
to the solution and the mixture was stirred at room temperature
for 18 hr. The reaction solvent was removed under reduced pres-
sure and the crude residue was purified by flash chromatography
(hexane/ethyl acetate: 8/2 to 1/1) to afford Compound 8g (0.28 g,
1
52 %). M.p 211.2ꢀC. H NMR (300 MHz, DMSO-d6) d 3.79(s,
3H), 7.04(d, J = 8.6 Hz, 2H), 7.28(s, 1H), 7.35(d, J = 7.9 Hz,
1H), 7.41(d, J = 7.5 Hz, 1H), 7.49(dd, J = 7.2, 7.5 Hz, 1H), 7.56
(dd, J = 7.2, 7.9 Hz, 1H), 7.58(d, J = 8.6 Hz, 2H) ppm. 13C
NMR (75 MHz, DMSO-d6) d 55.84, 115.15, 124.17, 124.53,
124.63, 126.48, 127.13, 128.25, 130.59, 131.79, 147.55, 164.18,
166.53, 167.55 ppm. HRMS (M+1)+ calcd for C17H14NO6S2
392.0263, found 392.0259. Anal. calcd. for C17H13NO6S2: C,
52.16; H, 3.35; N, 3.58. Found: C, 52.11; H, 3.41; N, 3.51.
(Z)-20-(4-Fluorobenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8h). Compound 8h was synthesized from the proce-
dure described for Compound 8g. Yield: 56 %. M.p 198.8ꢀC.
1H NMR (300 MHz, DMSO-d6) d 7.32(s, 1H), 7.33(m, 1H),
7.45(m, 3H), 7.56(m, 2H), 7.81(m, 2H) ppm. 13C NMR (75
MHz, DMSO-d6) d 117.26, 117.57, 123.99, 124.22, 126.99,
128.46, 128.57, 129.99, 131.52, 131.65, 131.92, 147.41,
166.72, 167.54 ppm. HRMS (M+1)+ calcd for C16H11FNO5S2
380.0063, found 380.0058. Anal. calcd. for C16H10FNO5S2: C,
50.65; H, 2.66; N, 3.69. Found: C, 50.61; H, 2.75; N, 3.65.
(Z)-20-(4-Bromobenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8i). Compound 8i was synthesized from the procedure
described for Compound 8g. Yield: 54 %. M.p 212.8ꢀC. 1H
NMR (300 MHz, DMSO-d6) d 7.23(s, 1H), 7.39(d, J = 7.7 Hz,
1H), 7.43(dd, J = 7.3, 7.8 Hz, 1H), 7.52(dd, J = 7.3, 7.7 Hz, 1H),
7.56(d, J = 7.8 Hz, 1H), 7.59(d, J = 8.6 Hz, 2H), 7.78(d, J = 8.6
Hz, 2H) ppm. 13C NMR (75 MHz, DMSO-d6) d 124.13, 124.20,
126.79, 126.93, 128.44, 128.57, 129.81, 129.95, 131.98, 132.52,
133.25, 147.33, 166.41, 167.43 ppm. HRMS (M+1)+ calcd for
C16H11BrNO5S2 439.9262, found 439.9263. Anal. calcd. for
C16H10BrNO5S2: C, 43.65; H, 2.29; N, 3.18. Found: C, 43.61; H,
2.32; N, 3.13.
(Z)-20-(3,4-Dimethoxybenzenesulfonyloxy)-5-benzylidene-
thiazolidine-2,4-dione (8j). Compound 8j was synthesized from the
procedure described for Compound 8g. Yield: 58 %. M.p 221.2ꢀC.
1H NMR (300 MHz, DMSO-d6) d 3.71(s, 3H), 3.77(s, 3H), 7.01(d,
J = 8.6 Hz, 1H), 7.02(s, 1H), 7.12(d, J = 8.6 Hz, 1H), 7.21(s, 1H),
7.39(d, J = 7.4 Hz, 1H), 7.42(d, J = 7.8 Hz, 1H), 7.49(dd, J = 7.4,
7.6 Hz, 1H), 7.58(dd, J = 7.6, 7.8 Hz, 1H) ppm. 13C NMR (75
MHz, DMSO-d6) d 55.60, 55.92, 109.62, 111.56, 122.82,
124.05, 124.22, 124.35, 126.44, 127.35, 128.12, 128.23, 131.77,
147.62, 149.11, 154.09, 166.83, 167.68 ppm. HRMS (M+1)+
calcd for C18H16NO7S2 422.0368, found 422.0362. Anal. calcd.
for C18H15NO7S2: C, 51.30; H, 3.59; N, 3.32. Found: C, 51.30;
H, 3.59; N, 3.32.
(Z)-5-(2-Hydroxybenzylidene)thiazolidine-2,4-dione (9). To a
solution of 2,4-thiazolidinedione (0.44 g, 3.75 mmol) and sodium
acetate (0.3 g, 3.75 mmol), 2-hydroxybenzaldehyde (0.46 g, 3.75
mmol) was added and the resulting mixture was stirred under re-
flux for 10 min. The reaction was cooled and the precipitate was
washed with water to afford the crude product. The crude product
was recrystallized with water and DMF to give 9 (0.71 g, 85 %).
1
M.p 196.5ꢀC. H NMR (300 MHz, DMSO-d6) d 6.89(d, J =8.0
Hz, 1H), 6.93(dd, J = 7.1, 7.6 Hz, 1H), 7.26(dd, J = 7.6, 8.0
Hz, 1H), 7.39(d, J = 7.1 Hz, 1H), 8.18(s, 1H) ppm. 13C NMR
(75 MHz, DMSO-d6) d 116.16, 119.69, 120.01, 121.96, 127.06,
128.33, 132.23, 157.30, 167.58, 168.22 ppm.
(Z)-20-(4-Methoxybenzenesulfonyloxy)-5-benzylidene-thiazoli-
dine-2,4-dione (8g). A mixture of (Z)-5-(2-Hydroxybenzylidene)
(Z)-20-(4-Isopropylbenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8k). Compound 8k was synthesized from the procedure
described for Compound 8g. Yield: 62 %. M.p 222.4ꢀC. 1H NMR
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2012
Synthesis and Antiproliferative Evaluation of 20-Arenesulfonyloxy-5-benzylidene-
thiazolidine-2,4-diones
797
(300 MHz, DMSO-d6) d 1.15(d, J = 6.9 Hz, 6H), 2.92(septet, J =
6.9 Hz, 1H), 7.32(s, 1H), 7.38(d, J= 8.1 Hz, 1H), 7.40(d, J = 7.1
Hz, 1H), 7.42(d, J = 8.5 Hz, 2H), 7.50(dd, J = 7.1, 7.5 Hz, 1H),
7.58(dd, J = 7.5, 8.1 Hz, 1H), 7.60(d, J = 8.5 Hz, 2H) ppm.13C
NMR (75 MHz, DMSO-d6) d 23.06, 33.43, 124.10, 124.20,
126.24, 126.85, 127.75, 128.33, 128.41, 130.94, 131.90, 147.58,
156.33, 166.48, 167.49 ppm. HRMS (M+1)+ calcd for
C19H18NO5S2 404.0626, found 404.0625. Anal. calcd. for
C19H17NO5S2: C, 56.56; H, 4.25; N, 3.47. Found: C, 56.53; H,
4.31; N, 3.41.
(Z)-20-(4-tert-Butylbenzenesulfonyloxy)-5-benzylidene-thiazolidine-
2,4-dione (8l). Compound 8l was synthesized from the procedure
described for Compound 8g. Yield: 67 %. M.p 207.4ꢀC. 1H
NMR (300 MHz, DMSO-d6) d 1.22(s, 9H), 7.32(s, 1H), 7.39(d,
J = 8.3 Hz, 1H), 7.42(d, J = 7.0 Hz, 1H), 7.49(dd, J = 7.0, 7.9
Hz, 1H), 7.54(d, J = 8.7 Hz, 2H), 7.55(dd, J = 7.9, 8.3 Hz, 1H),
7.61(d, J = 8.7 Hz, 2H) ppm.13C NMR (75 MHz, DMSO-d6) d
30.44, 35.05, 124.09, 124.12, 126.11, 126.59, 126.76, 128.16,
128.32, 130.62, 131.89, 147.56, 158.57, 166.44, 167.44 ppm.
HRMS (M+1)+ calcd for C20H20NO5S2 418.0783, found
418.0784. Anal. calcd. for C20H20NO5S2: C, 57.54; H, 4.59; N,
3.35. Found: C, 57.51; H, 4.62; N, 3.34.
123.09, 123.65, 124.45, 124.61, 126.84, 127.18, 127.56,
127.64, 128.16, 128.63, 129.37, 131.47, 131.73, 133.80,
136.70, 147.57, 166.19, 167.42 ppm. HRMS (M+1)+ calcd for
C20H14NO5S2 412.0313, found 412.0311. Anal. calcd. for
C20H13NO5S2: C, 58.38; H, 3.18; N, 3.40. Found: C, 58.34; H,
3.21; N, 3.37.
(Z)-20-(2-Naphthylsulfonyloxy)-5-benzylidene-thiazolidine-2,4-
dione (8p). Compound 8p was synthesized from the procedure
described for Compound 8g. Yield: 69 %. M.p 210.0ꢀC. 1H
NMR (300 MHz, DMSO-d6) d 7.26(s, 1H), 7.33(d, J = 7.3 Hz,
1H), 7.41(d, J = 8.0 Hz, 1H), 7.46(dd, J = 7.5, 8.0 Hz, 1H),
7.56(dd, J = 7.3, 7.5 Hz, 1H), 7.63(dd, J = 6.8, 8.0 Hz, 1H),
7.66(dd, J = 6.8, 6.9 Hz, 1H), 7.75(d, J = 6.9 Hz, 1H), 8.00(d,
J = 8.0 Hz, 1H), 8.06(d, J = 8.0 Hz, 1H), 8.11(d, J = 8.0 Hz,
1H), 8.45(s, 1H) ppm.13C NMR (75 MHz, DMSO-d6) d 122.36,
123.62, 124.09, 126.97, 127.25, 127.78, 128.12, 128.30, 128.36,
129.73, 130.14, 130.25, 130.42, 131.54, 131.77, 135.21, 147.49,
166.87, 167.56 ppm. HRMS (M+1)+ calcd for C20H14NO5S2
412.0313, found 412.0314. Anal. calcd. for C20H13NO5S2: C,
58.38; H, 3.18; N, 3.40. Found: C, 58.32; H, 3.23; N, 3.43.
Cell culture. Cancer cells were purchased from Bioresource
Collection and Research Center in Taiwan. Each cell line was
maintained in the standard medium and grown as a monolayer
in Dulbecco’s Modified Eagle Medium (DMEM) containing
10% fetal bovine serum, 2 mM glutamine, 100 units/mL
penicillin, and 100 g/mL streptomycin. Cultures were maintained
at 37ꢀC with 5 % CO2 in a humidified atmosphere.
(Z)-20-(4-Trifluoromethxybenzenesulfonyloxy)-5-benzylidene-
thiazolidine-2,4-dione (8m). Compound 8m was synthesized from
the procedure described for Compound 8g. Yield: 64 %. M.p
1
214.4ꢀC. H NMR (300 MHz, DMSO-d6) d 7.20(s, 1H), 7.43(d,
J = 7.8 Hz, 1H), 7.45(d, J = 7.2 Hz, 1H), 7.53(dd, J = 7.2, 7.5
Hz, 1H), 7.61(dd, J = 7.5, 7.8 Hz, 1H), 7.93(m, 4H) ppm. 13C
NMR (75 MHz, DMSO-d6) d 121.21, 123.88, 124.26, 124.83,
126.77, 127.15, 128.52, 128.71, 129.33, 132.10, 134.46, 137.45,
147.31, 166.33, 167.21 ppm. HRMS (M+1)+ calcd for
C17H11F3NO6S2 445.9980, found 445.9982. Anal. calcd. for
C17H10F3NO6S2: C, 45.84; H, 2.26; N, 3.14. Found: C, 45.88; H,
2.31; N, 3.07.
(Z)-20-(4-Biphenylsulfonyloxy)-5-benzylidene-thiazolidine-2,4-
dione (8n). Compound 8n was synthesized from the procedure
described for Compound 8g. Yield: 67 %. M.p 168.7ꢀC. 1H
NMR (300 MHz, DMSO-d6) d 7.21(m, 1H), 7.22(s, 1H), 7.39
(m, 3H), 7.47(t, J = 7.4 Hz, 1H), 7.52(dd, J = 7.4, 8.5 Hz, 2H),
7.67(d, J = 8.5 Hz, 2H), 7.81(m, 4H) ppm. 13C NMR (75 MHz,
DMSO-d6) d 114.48, 122.79, 127.31, 127.72, 127.82, 128.15,
128.83, 128.96, 129.07, 129.87, 132.65, 138.10, 139.08,
146.53, 147.16, 174.92, 181.92 ppm. HRMS (M+1)+ calcd for
C22H16NO5S2 438.0470, found 438.0468. Anal. calcd. For
C22H15NO5S2: C, 60.40; H, 3.46; N, 3.20. Found: C, 60.36; H,
3.52; N, 3.14.
(Z)-20-(1-Naphthylsulfonyloxy)-5-benzylidene-thiazolidine-2,4-
dione (8o). Compound 8o was synthesized from the procedure
described for Compound 8g. Yield: 68 %. M.p 173.2ꢀC. 1H
NMR (300 MHz, DMSO-d6) d 7.10(m, 1H), 7.39(m, 1H), 7.43
(dd, J = 6.8, 8.2 Hz, 1H), 7.44(s, 1H), 7.45(dd, J = 6.8, 8.5 Hz,
1H), 7.64(dd, J = 7.4, 7.9 Hz, 1H), 7.73(m, 2H), 8.11(d, J = 7.4
Hz, 1H), 8.14(d, J = 7.9 Hz, 1H), 8.37(d, J = 8.2 Hz, 1H), 8.51
(d, J = 8.5 Hz, 1H) ppm. 13C NMR (75 MHz, DMSO-d6) d
MTT assay for cell viability. Cells were plated in 96-well
microtiter plates at a density of 5 ꢂ 103/well and incubated for
24 h. After that, cells were treated with vehicle alone (control)
or compounds (drugs were dissolved in DMSO previously) at
the concentrations indicated. Treated cells were further
incubated for 48 h. Cell survival is expressed as percentage
of control cell growth. The 3-[4, 5-Dimethylthiazol-2-yl]-2,
5-diphenyltetrazolium bromide (MTT, 2 mg/mL) dye reduction
assay in 96-well microplates was used. The assay is dependent
on the reduction of MTT by mitochondrial dehydrogenases of
viable cell to a blue formazan product, which come be measured
spectrophotometrically. Tumor cells were incubated in each well
with serial dilutions of the tested compounds. After 2 days of
incubation (37ꢀC, 5 % CO2 in a humid atmosphere) 100 mL of
MTT (2 mg/mL in PBS) was added to each well and the plate was
incubated for a further 2 h (37ꢀC). The resulting formazan was
dissolved in 100 mL DMSO and read at 570 nm. The percentage of
growth inhibition was calculated by the following equation:
percentage growth inhibition = (1ꢃAt/Ac) ꢂ 100, where At and Ac
represent the absorbance in treated and control cultures, respectively.
The drug concentration causing a 50 % cell growth inhibition (GI50)
was determined by interpolation from dose-response curves. All
determinations were carried out in four to six separated experiments.
Statistical analysis. Data are presented as the meanꢁsem
(standard error of the mean) from four to six separated
experiments. Statistical analyses were performed using
Bonferroni t-test method after ANOVA for multigroup
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

798
E. M. Chen, P.-J. Lu, and A. Y. Shaw
Vol 49
comparison and Student’s t-test method for two-group
comparison. P = 0.05 was considered significant. Analysis of
linear regression (at least five data within 20–80% inhibition)
was used to calculate GI50 value.
concluded that the new synthesized 20-arenesulfonyloxy-
5-benzylidene-thiazolidine-2,4-diones have shown to be
antiproliferative agents deserved for further study.
Acknowledgments. This work was supported by the National
Science Council of the Republic of China to A.Y.S.
CONCLUSIONS
In summary, we have successfully synthesized a series
of 20-arenesulfonyloxy-5-benzylidene-thiazolidine-2,4-diones
by employing two synthetic pathways. We found that the
optimal yield of Knoevenagel condensation was obtained
in the presence of 0.5 equiv of piperidine in refluxed
ethanol for 18–22 hr. In addition, we also found that
initial preparation of 5-[20-hydroxybenzylidene]-2,4-
thiazolidinone (9) followed by nucleophilic substitution
with arylsulfonyl chlorides exhibited better efficiency.
Upon exposure of five carcinoma cells, none of test com-
pounds exhibited antirpoliferative activity against SW620
cells. We found that only 8c and 8e showed significant
antiproliferative activity against PC-3 and BT474 cells
with GI50 values of 8.4 and 20.6 mM, respectively. We also
obtained that SKHep exhibited some interesting structure-
activity relationship results in response to TZD treatment.
Among alkyl group-substituted TZD analogs, 8a (4-Me,
GI50, 9.4 mM) and 8k (4-iso-propyl, GI50, 9.8 mM) revealed
better antiproliferative activity than those of bulkier alkyl
group-substituted TZD analogs such as t-butyl (8l, GI50,
15.7 mM) and phenyl (8n, GI50, 23.1 mM). On the other
hand, we found that halogen-substituted analogs 8c (4-Cl,
GI50, 8.7 mM), 8h (4-F, GI50, 16.5 mM) and 8i (4-Br,
GI50, 18.9 mM) showed better antiproliferative activity
than others against H460 cells. Taken together, we
REFERENCES AND NOTES
[1] Strumvoll, M.; Haring, H. U. Ann Med 2002, 34, 217.
[2] Hossain, U.; Bhattacharia, S. Bioorg Med Chem Lett 2007,
17, 1149.
[3] Ottana, R.; Maccari, R.; Barreca, M. L.; Bruno, G.; Rotondo, A.;
Rossi, A.; Chiricosta, G.; Di Paola, R.; Sautebin, L.; Cuzzocrea, S.; Vigorita,
M. G. Bioorg Med Chem 2005, 13, 4243.
[4] Vicini, P.; Geronikaki, A.; Anastasia, K.; Incerti, M.; Zani, F.
Bioorg Med Chem 2006, 14, 3859.
[5] Gududuru, V.; Hurh, E.; Dalton, J. T.; Miller, D. D. Bioorg
Med Chem Lett 2004, 14, 5289.
[6] Ottana, R.; Carotti, S.; Maccari, R.; Landini, I.; Chiricosta, G.;
Caciagli, B.; Vigorita, M. G.; Mini, E. Bioorg Med Chem Lett 2005, 15,
3930.
[7] Elbarbary, A. A.; Khodair, A. I.; Pedersen, E. B.; Nielsen, C.
Monatsh Chem 1994, 125, 593.
[8] El-Feky, S. A. H. Pharmazie 1992, 48, 894.
[9] Liu, H. L.; Li, Z. C.; Anthonsen, T. Molecules 2000, 5, 1055.
[10] Mobinikhaledi, A.; Foroughifar, N.; Kalhor, M.; Mirabolfathy,
M. J Hectrocycl Chem 2010, 47, 77.
[11] Kalaiya, S. B.; Parikh, A. R. J Indian Chem Soc 1987, 64, 172.
[12] Popov-Pergal, K. M.; Poleti, D.; Ranèiæ, M. P.; Meden, A.;
Pergal, M. V. J Hectrocycl Chem 2010, 47, 224.
[13] Lima, L. M.; Frattani, F. S.; dos Santos, J. L.; Castro, H. C.;
Fraga, C. A. M.; Zingali, R. B.; Barreiro, E. J. Eur J Med Chem 2008,
43, 348.
[14] Li, G.-S.; Wang, C.; Li, J.-C.; Zhou, Y.-X.; Zhao, H.-R.; Li, P.;
Geng, H.-J. Chin J Appl Chem 2004, 21, 10, 1069.
[15] Mosman, T. J Immunol Method 1983, 65, 55.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet