Synthesis, stereochemistry and biological activity of some novel long alkyl chain substituted thiazolidin-4-ones and thiazan-4-one from 10-undecenoic acid hydrazide

Article abstract of DOI:10.1016/j.ejmech.2004.10.003

The synthesis of four novel compounds, (i) [(11-{[2-(3-nitrophenyl)-4-oxo- 1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)sulfanyl]acetic acid (4), (ii) N-[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]undec-10-enamide (5), (iii) 2-[(11-{[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11- oxoundecyl)sulfanyl]propanoic acid (6) and (iv) 3-[(11-{[2-(3-nitrophenyl)-4- oxo-1,3-thiazinan-3-yl]amino}-11-oxoundecenyl) sulfanyl]propanoic acid (8) from 10-undecenoic acid hydrazide (1) via m-nitrobenzaldehyde-10-undecenohydrazone (2) using mercaptoacetic acid in (i), 2-mercaptopropionic acid in (ii and iii) and 3-mercaptopropionic acid in (iv) is described. The uncyclized products, ({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxo-undecyl}sulfanyl)acetic acid (3) and 3-({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxoundecyl}sulfanyl) propanoic acid (7) are also obtained in (i) and (iv), respectively. The hydrazones (2), (3) and (7) exist in two conformers as synperiplanar and antiperiplanar. Structural assignment, stereochemistry and biological assays are discussed.

Full text of DOI:10.1016/j.ejmech.2004.10.003

European Journal of Medicinal Chemistry 40 (2005) 173–184
www.elsevier.com/locate/ejmech
Original article
Synthesis, stereochemistry and biological activity of some novel long
alkyl chain substituted thiazolidin-4-ones and thiazan-4-one from
10-undecenoic acid hydrazide
V.P. Mujeebur Rahman a, Sayeed Mukhtar a, Wajid Husain Ansari a,*, Guy Lemiere b
a Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India
b Department of Chemistry (Natural Products), University of Antwerp (RUCA), Groenenborgerlaan 171 B-2020, Belgium
Received 28 May 2004; received in revised form 8 October 2004; accepted 11 October 2004
Available online 30 November 2004
Abstract
The synthesis of four novel compounds, (i) [(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)sulfanyl]acetic
acid (4), (ii) N-[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]undec-10-enamide (5), (iii) 2-[(11-{[5-methyl-2-(3-nitrophenyl)-4-
oxo-1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)sulfanyl]propanoic acid (6) and (iv) 3-[(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazinan-3-
yl]amino}-11-oxoundecenyl) sulfanyl]propanoic acid (8) from 10-undecenoic acid hydrazide (1) via m-nitrobenzaldehyde-10-
undecenohydrazone (2) using mercaptoacetic acid in (i), 2-mercaptopropionic acid in (ii and iii) and 3-mercaptopropionic acid in (iv) is
described. The uncyclized products, ({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxo-undecyl}sulfanyl)acetic acid (3) and 3-({11-[(2E)-
2-(3-nitrobenzylidene)hydrazino]-11-oxoundecyl}sulfanyl)propanoic acid (7) are also obtained in (i) and (iv), respectively. The hydrazones
(2), (3) and (7) exist in two conformers as synperiplanar and antiperiplanar. Structural assignment, stereochemistry and biological assays are
discussed.
© 2004 Elsevier SAS. All rights reserved.
Keywords: Acylhydrazone; Thiazolidin-4-ones; Tetrahydro-1,3-thiazin-4-one; Terminal carboxymethyl/ethylthio acylhydrazones; Cytotoxic activity; Antimi-
crobial activity
1. Introduction
inhibitory [13], calcium antagonist [14], cardioprotective
[15], antiischemic activity [16a,b] and a promising agent for
treating Alzheimer [11b], cancer [17], AIDS [18a,b] and
hepatitis B [18a]. Among the tetrahydro-1,3-thiazin-4-ones,
2-(4-chlorophenyl)-3-methyl-tetrahydro-1,3-thiazin-4-one-
1,1-dioxide (chloromezanone) is widely used as anticoagu-
lant [19], tranquilizer and muscle spasm [20]. Other deriva-
tives show wide range activities as antimicrobial [21a,b],
antiarthritic [22], antirheumatic [23] and in the treatment of
cardiac arrythimia [13], peptic ulcer [24] and occular inflam-
mation [25]. Also a number of long chain alkyl thioethers has
been reported for their antimicrobial [26a,b], tranquilizer
[27], analgesic and antidepressant [28] activities. As part of
our aim in search of biologically active nitrogen and sulfur
containing heterocyclic compounds, we have recently re-
ported [29,30] the synthesis and cytotoxic activity of two
novel compounds, 2-[2-carboxymethylthio-2-(4-chloro-
phenyl) ethyl]-2-(4-chlorophenyl)-4-thiazolidinone and
2-[2,2-bis(4-chlorophenyl) ethyl]-2-(4-chlorophenyl)thiazo-
In recent years attention has been focussed on the synthe-
sis of naturally occurring long alkyl chain substituted hetero-
cycles and their analogues [1–3]. The interest in thiazolidin-
4-ones and tetrahydro-1,3-thiazin-4-ones for medical
applications is also increasing strongly. (–) 2-(5-Carboxy-
pentyl) thiazolidin-4-one (actithiazic acid) isolated from the
culture broth of a strain of streptomyces shows highly spe-
cific in vitro activity against Mycobacterium tuberculosis
[4a,b]. Other substituted thiazolidin-4-ones exhibit diverse
biological activities such as anticonvulsant [5], antidiarrheal
[6], antiarthritic [7], anti-platelet activating factor activity
[8,a,b,c], antihistaminic [9a,b,c], antimicrobial [10a,b,c],
antidiabetic [11a,b], oxygenase inhibitory [12], K+ channel
* Corresponding author. Fax:(internet) +91 571 270 2064.
E-mail addresses: whansari_amu@indiatimes.com (W.H. Ansari),
lemiere@ruca.ua.ac.be (G. Lemiere).
0223-5234/$ - see front matter © 2004 Elsevier SAS. All rights reserved.
doi:10.1016/j.ejmech.2004.10.003

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V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
lidin-4-one from p,p′-dichlorochalcone using mercaptoace-
tic acid in the presence of ammonium carbonate. Evaluation
for cytotoxic activity was performed against 60 cell lines of
nine types of human cancers leukemia, lung, colon, CNS,
melanoma, ovarian, renal, prostate and breast. Noteworthy
results are obtained in the case of melanoma, colon and renal
cancers where the reduction in growth is 52%, 80% and 91%,
respectively, at the concentration of 1.0 × 10–4 M.
Because 4-thiazolidinones and thiazanones substituted in
the 2-position were proven to be biologically very potent and
selective and in anticipation that the lipophilization by long
alkyl chain thioether substitution in the ring may further
enhance their activity, prompted us to undertake this prob-
lem. The present paper deals with the synthesis, stereochem-
istry and biological screening of four novel compounds, (i)
[(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-
11-oxoundecyl)sulfanyl]acetic acid (4) (ii) N-[5-methyl-2-(3-
nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]undec-10-enamide
prepared following a published procedure [31] by refluxing
solution of 10-undecenoic acid hydrazide with
a
m-nitrobenzaldehyde (molar ratio, 1:1) in anhydrous ben-
zene for 5 h as yellow crystalline needles in 87.0% yield. The
compound (2) was then separately reacted with mercaptoace-
tic acid, 2-mercaptopropionic acid and 3-mercaptopropionic
acid (molar ratio, 1:3, in each case) in anhydrous benzene
monitoring (TLC) and refluxing the reaction mixtures for 16,
22 and 26 h, respectively, with azeotropic removal of water.
The products on chromatography over a silica gel column
using pet. ether (60–80 °C)–diethylether (1:1) as eluent,
yielded the respective compounds (Fig. 1). It is noteworthy
that no uncyclized product is formed in the reaction of
2-mercaptopropionic acid with the hydrazone (2) while an
uncyclized adduct is formed both in the case of mercaptoace-
tic acid and 3-mercaptopropionic acid. This is due to the fact
that mercaptoacetic acid and 3-mercaptopropionic acid first
undergo anti-Markovnikov’s addition at the terminal olefinic
bond and then cyclocondensation at the C=N double bond
whereas 2-mercaptopropionic acid first undergoes cyclocon-
densation at the C=N double bond and then addition at the
olefinic bond of the hydrazone (2) to give the respective
products. The increased nucleophilicity of the mercapto
group in the 2-mercaptopropionic acid probably facilitates
cyclocondensation. The course of addition of mercapto acids
to terminal olefinic bond is attributed to the free radical
mechanism [32].
(5
) (iii) 2-[(11-{[5-methyl-2-(3-nitro-phenyl)-4-oxo-1,3-
thiazolidin-3-yl]amino}-11-oxoundecyl) sulfanyl]propanoic
acid (6) and (iv) 3-[(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thia-
zinan-3-yl]amino}-11-oxoundecenyl) sulfanyl]propanoic
acid (8) along with two adducts (3) and (7), from 10-
undecenoic acid hydrazide (1) via m-nitrobenzaldehyde-10-
undecenohydrazone (2) using mercaptoacetic acid in (i),
2-mercaptopropionic acid in (ii and iii) and 3-mercapto-
propionic acid in (iv). The uncyclized adducts, ({11-[(2E)-2-
(3-nitrobenzylidene)hydrazino]-11-oxoundecyl}sulfanyl)-
acetic acid (3) and 3-({11-[(2E)-2-(3-nitrobenzylidene)
hydrazino]-11-oxoundecyl}sulfanyl)propanoic acid (7) are
obtained in (i) and (iv), respectively. It is believed that the
mercaptoacetic acid and 3-mercaptopropionic acid first un-
dergo addition to the terminal olefinic bond giving the ad-
ducts (3) and (7) while 2-mercaptopropionic acid first under-
goes cyclocondensation at the C=N double bond and thus no
uncyclized adduct is formed in (ii) and (iii). The stere-
ochemical investigation of the hydrazones (2), (3) and (7)
confirm the existence of two conformers as synperiplanar
(major) and antiperiplanar (minor). The hydrazone (2),
thiazolidin-4-one derivatives (4) and (5) and thiazan-4-one
derivative (8) are evaluated for cytotoxic activity first against
three cell lines of three types of human cancers: lung, breast
and CNS. The compound (5) found to be active in a panel of
three cell lines is then screened on a full panel of 60 cell lines
of nine types of human cancers: leukemia, lung, colon, CNS,
melanoma, ovarian, renal, prostate and breast. Screening
results of seven compounds (2)–(8) are also summarized for
antimicrobial activity against four bacteria, Escherichia coli,
Bacillus subtilis, Staphylococcus aureus and Pseudomonas
aeruginosa and one fungus, Candida albicans.
The structures and stereochemistry of (2), (3) and (7) have
1
been established by a combined study of IR, DCI-MS, H-
NMR, NOE, 13C-NMR and HETCOR spectra (spectral data
of the representative compound (2) are shown in Tables 1 and
2 and that of (3) and (7) in Section 4). IR spectra exhibited
characteristic absorption peaks corresponding to N–H/O–H,
C=O, C=C, C=N and NO2 groups. DCI-MS spectra showed
characteristic [M + 1]+ peaks corresponding to their molecu-
lar weights. The assignments of all the signals to individual H
or C-atoms have been performed on the basis of typical
d-values, J-constants, a HETCOR spectrum and by compar-
ing with the reference spectra (SDBS) [33] of 10-undecenoic
1
acid, 10-undecenamide and m-nitrobenzaldehyd. The H-
NMR and 13C-NMR spectra of these compounds dissolved
in acetone-d6 showed double signals especially of NH,
H-7 and H-2′ and of C-7, C-2′, C-3′, C-2 and C-6 which
indicated that these molecules are present in two stereoiso-
meric forms. The two forms were found to be in the ratio
(3:1) as calculated from the integration values of the NH- and
H-2′ signals. This can be thought of about E/Z isomers of the
C=N bond or stabile conformers around single bond such as
in the CO–NH group. To investigate this, we irradiated the
NH-proton, which resulted in a NOE-enhancement of H-7
(both signals), showing that the NH-proton and H-7 (in both
forms) are very near to each other. This can only be the case
in E-isomers. Further, in case of H-2′ signals, a NOE-
enhancement was observed only for the largest H-2′ signal
(75%) and absolutely no NOE-enhancement was seen for the
small H-2′ signal (25%) (Table 1). This showed that only in
2. Results and discussion
2.1. Chemistry
The synthesis of compounds (3)–(8) has been performed
in two steps: the hydrazone (2) as a precursor was first

V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
175
Fig. 1. Synthesis of: (2) (a) (1)/m-Nitrobenzaldehyde (molar ratio, 1:1), anhydrous benzene, reflux, 5 h. (3) + (4) (b) (2)/HS·CH2·COOH (molar ratio, 1:3),
anhydrous benzene, reflux, 16 h. (5) + (6) (b′) (2)/HS·CH(CH3)·COOH (molar ratio, 1:3), anhydrous benzene, reflux, 22 h. (7) + (8) (b″)
(2)/HS·CH2·CH2·COOH (molar ratio, 1:3), anhydrous benzene, reflux, 26 h.
Table 1
1H-NMR and NOE data of representative compound (2) in acetone-d6
H number
d (ppm)
Integration
Multiplicity
J (Hz)
NOE
7
8.17, 8.46 (~75%, 25%)
10.41, 10.76 (~75%, 25%)
1H
1H
s
s
NH
H-7 (~25%, 75%)
H-2′ (~75%)
2′
2.33, 2.74 (~25%, 75%)
2H
t
J2′,3′ 7.32; 7.48
J ≈ 7.32
3′
1.69
1.31
2.02
5.78
4.88
4.96
8.49
8.22
7.71
8.12
2H
br p
br s
td
4′–8′
9′
5 × 2H
2H
J9′,10′ 6.72; J9′,8′ 7.32
10′
1H
tdd
dd
dd
dd
dd
dd
dd
J10′,9′ 6.72; J10′,H 17.09; J10′,H 10.22
Z
E
HE
1H
JH ,10′ 10.22; JH
2.14
2.14
,H
E
E
Z
HZ
1H
JH ,10′ 17.09; JH
,H
Z
Z
E
Ar-2
Ar-4
Ar-5
Ar-6
1H
JAr-2,Ar-6/4 1.99; JAr-2,Ar-4/6 1.83
JAr-4,Ar-5 7.94; JAr-4,Ar-2/6 1.83
JAr-5,Ar-6 7.78; JAr-5,Ar-4 7.94
JAr-6,Ar-5 7.78; JAr-6,Ar-2/4 1.99
1H
1H
1H
the major form, the H-2′ protons are near to the NH-proton. It
was, therefore, concluded that both forms of the products are
due to a major synperiplanar CO–NH conformation (75%)
and a minor antiperiplanar CO–NH conformation (25%),
which are in equilibrium with each other as presented in
Fig. 2. An additional argument for this conclusion is the fact
The structures of (4), (5), (6) and (8) have been confirmed
1
by IR, DCI-MS, H-NMR, 13C-NMR and COSY spectra.
The assignments of all the signals to individual H- and C-
atoms (Tables 3, 4, 5 and Section 4) have been made from
their typical chemical shift values, coupling constants, rela-
tive integrations and by comparison with the spectra of the
precursor (2) (Tables 1, 2). IR spectra displayed characteris-
tic absorption bands corresponding to NH, OH, COOH,
CON, CONH, phenyl, NO2 and S-CH2 groups. DCI-MS
spectra showed [M + 1]+ peaks confirming their molecular
weights which are equivalent to the molecular weights of the
precursor (2) plus 2 mol of respective mercapto acids minus
1 mol of water except that of (5) where there is only 1 mol of
the acid. This indicated that addition and cyclocondensation
of the acids have occurred at the terminal C=C and C=N
bonds of (2) forming thiazolidinone/thiazanone rings except
in (5) where thiazolidinone ring has been formed only. The
1
that in the H-NMR spectra of the above compounds dis-
solved in DMSO-d6 again two forms are observed but now in
a 2:3 ratio for compound (2) and a 3:2 ratio for compounds
(3) and (7). This observation again is an indication that the
two forms are stabile conformers, which are in equilibrium
with each other, an equilibrium that is dependent on the
polarity of the solvent. The 1H-NMR and 13C-NMR spectra
of (3) and (7) also revealed that they are formed by an
anti-Markovnikov’s addition of mercaptoacetic acid/3-
mercaptopropionic acid to the terminal C=C double bond of
compound (2).

176
V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
Table 2
couplings of these protons were further confirmed by a
COSY spectrum (Table 3) where the broad signal at d 6.04
(H-2) showed a cross peak with two double doublets at d 3.75
(H-5cis) and at d 3.84 (H-5trans). Interestingly all the signals
13C-NMR and HETCOR data of (2) in acetone-d6
C number d (ppm)
HETCOR correlation
with
7
140.79, 144.53 (~75%, 25%)
H-7 (~75%, 25%)
1
in both the H-NMR and 13C-NMR spectra of (5) and (6)
1′
170.07, 172.12 (~75%, 25%)
were found to be similar except that (5) showed the signals
corresponding to a terminal double bond whereas (6) showed
the signals for a terminal thioether moiety (Tables 4, 5). This
was also confirmed by a DCI-mass spectra of (5) and (6)
which showed [M + 1]+ peaks at m/z 420 and m/z 526,
respectively, differing by a molecular weight of 106, which
corresponds to a HS·CH(CH3)·COOH group. This indicated
that in this case first the cyclocondensation of 2-mercapto-
propionic acid to the C=N double bond has occurred forming
(5) as the first product followed by the addition of
2-mercaptopropionic acid to the terminal double bond lead-
ing to the formation of (6). In addition, both the spectra
showed that these compounds contain a mixture of isomers
with cis and trans standing methyl and 3-nitrophenyl groups.
In the 1H-NMR/13C-NMR spectra (Section 4) of (8), the ring
methylene protons/carbons (–CH2–CH2–S–) appeared at dH
2.94/dC 37.24 (H-5/C-5) and dH 3.10/dC 27.59 (H-6/C-6) in
addition to the methylene protons/carbons of terminal thioet-
her moiety at dH 2.75/dC 24.53 (H-1″/C-1″) and dH 2.58/dC
35.25 (H-2″/C-2″) confirming the formation of tetrahydro-
1,3-thiazin-4-one ring. On the basis of above spectral find-
ings, structures and preferred conformation deduced are
shown in Fig. 3.
2′
33.09, 35.55 (~75%, 25%)
H-2′ (~75%, 25%)
H-3′
3′
25.41, 26.07 (~75%, 25%)
4′–8′
9′
29.22–30.3
34.42
H-4′–8′
H-9′
10′
139.81
114.59
137.68
121.8
H-10′
11′
HE-11′, HZ-11′
Ar-1
Ar-2
Ar-3
Ar-4
Ar-5
Ar-6
H–Ar-2
149.72
124.56
130.98
133.3
H–Ar-4
H–Ar-5
H–Ar-6
2.2. Study for biological activity
The newly synthesized compounds were evaluated for the
cytotoxic activity against malignant human tumor cells and
also for their antimicrobial (antibacterial and antifungal)
activity.
2.2.1. Cytotoxic activity against malignant human tumor
cells
Out of the newly synthesized compounds, (2), (4), (5) and
(8) were selected by the National Cancer Institute (NCI)
developmental therapeutic program for the in vitro cell line
screening to investigate their antitumor activity. The com-
pounds were first evaluated as one dose primary anticancer
assay in a three cell lines panel consisting of three types of
human cancers: breast (MCF7), lung (NCI-H460) and CNS
(SF-268) [34,35]. In the screening protocol, each cell line
was inoculated and preincubated for 24–48 h on a microtiter
plate. Test agents were then added at a single concentration
and the culture incubated for further 48 h. End point determi-
nations were made with alamar blue [36]. Results for each
test agent were reported as the percent growth of the treated
cells when compared to the untreated control cells. Com-
pounds that reduced the growth of any one of the cell lines to
approximately 32% or less are considered to be active. The
preliminary screening results are shown in Table 6. The
compound (5) demonstrated to be active in three cell lines,
Fig. 2. Stereoisomeric forms of (2), (3) and (7).
fragment ion peaks especially [(M + 1) – COCH2S]+ and
[(M + 1) – COCH2CH2S]+ are the diagnostic peaks for
thiazolidinone and thiazanone rings. The 1H-NMR and 13C-
NMR spectral data are in strong agreement with the forma-
tion of thiazolidin-4-one/tetrahydro-1,3-thiazin-4-one rings.
The H-7/C-7 signals of (2) have shifted to higher fields from
dH 8.17–8.46 (~75%, 25%)/dC 140.79–144.53 (~75%, 25%)
to dH 6.04/dC 62.23 in (4), to dH 6.01–6.04/dC 61.16 in (5) and
(6) and to dH 6.14/dC 66.02 in (8) due to formation of the ring
by the addition of mercapto acids at the C=N double bond.
1
Also in H-NMR spectrum of (4), the two diastereotopic
hydrogens of the thiazolidinone ring at C-5 appeared as a
double doublet by coupling with H-2 at d 3.84 (J = 15.87,
1.68, H-5trans) and d 3.75 (J = 15.87, 0.92, H-5cis). The

V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
177
Table 3
1H-NMR, 13C-NMR and COSY data of (4) in acetone-d6
H number
2
d (ppm)
6.04
Integration
Multiplicity
J (Hz)
COSY
C number
2
d (ppm)
62.23
1H
1H
1H
s
H-5cis, H-5trans
H-2
5trans
5cis
NH
3.84
dd
dd
J5trans,5cis 15.87; J5trans,H-2 1.68
J5cis,5trans 15.87; J5cis,H-2 0.92
4
172.17
34.09 a
171.71
33.09
3.75
H-2
5
Not appeared
2.08
1′
2′
2H
t
J2′,3′ 7.32
J ≈ 6.86
H-3′
2′
3′
1.5
2H
br p
br s
br p
t
H-2′, H-4′
H-4′, H-9′
H-11′, H-9′
3′
25.97
4′–9′
10′
1.19
6 × 2H
2H
4′–11′
1″
29.5–30.0
33.8 a
1.59
J ≈ 7.48
11′
2.64
2H
J11′,10′ 6.86
2″
169.67
142.18
124.76
149.54
123.63
131.01
135.31
1″
3.22
2H
s
Ar-1
Ar-2
Ar-3
Ar-4
Ar-5
Ar-6
Ar-2
Ar-4
Ar-5
Ar-6
8.34
1H
dd
dd
dd
dd
JAr-2,Ar-6/4 1.99; JAr-2,Ar-4/6 1.98
JAr-4,Ar-5 8.1; JAr-4,Ar-6/2 2.23
JAr-5,Ar-4 8.1; JAr-5,Ar-6 7.94
JAr-6,Ar-5 7.94
8.24
1H
7.71
1H
7.95
1H
JAr-6,Ar-2/4 1.99
a Assignment may be reversed.
Table 4
1H-NMR data of (5)/(6) in acetone-d6
H number
d (ppm)
Integration
Multiplicity
d/d
J (Hz)
2cis (5)/(6)
2trans (5)/(6)
5cis (5)/(6)
6.01/6.01
6.04/6.04
4.04/4.05
1H/1H
1H/1H
1H/1H
J2cis,5 0.91/0.91
d/d
J2trans,5 1.53/1.53
qd/qd
J5,CH −57.02;
3
J5cis,2 0.91/7.02, 0.91
5trans (5)/(6)
4.11/4.11
1H/1H
qd/qd
J5,CH −57.02;
3
J5trans,2 1.53/7.02, 1.53
5-CH3cis (5)/(6)
5-CH3trans (5)/(6)
N–H (5)/(6)
2′ (5)/(6)
1.59/159
1.61/1.61
9.28/9.28
2.11/2.11
1.5/1.5
3H/3H
3H/3H
1H/1H
2H/2H
2H/2H
d/d
JCH ,H−57.02⁄7.02
3−5
d/d
JCH ,H−57.02⁄7.02
3−5
s/s
t/t
J2′,3′ 7.33/7.33
J ≈ 7.33/7.17
3′ (5)/(6)
br p/ br p
4′–9′ (5)/(6)
10′ (5)
1.22/1.22
5.81
6 × 2H/6 × 2H
2H
br s/br s
tdd
J10’,9’ 6.72; J10’,H 17.09;
Z
J10’H 10.23,
E
H
H
E (5)
Z (5)
4.9
1H
dd
JH ,10’10.23;JH
2.13
2.13
H
Z
E
E’
4.98
1H
dd
JH ,10’17.09; JH
H
Z
Z
E’
10′ (6)
11′ (6)
1.59
2H
br p
t
J ≈ unresolved
J11′,10′.7.78
2.64
1H
1″ (6)
3.42
1H
q
JCH −1″, H–1″ 7.02
3
1″-CH3 (6)
Ar-2 (5)/(6)
Ar-4 (5)/(6)
Ar-5 (5)/(6)
Ar-6 (5)/(6)
1.6
3H
d
JCH −1″, H–1″ 7.02
3
8.34/8.34
8.26/8.26
7.73/7.73
7.95/7.95
1H/1H
1H/1H
1H/1H
1H/1H
dd/dd
dd/dd
dd/dd
dd/dd
JAr-2,Ar-4/6 1.99; JAr-2,Ar-6/4 1.83/1.98, 1.83
JAr-4,Ar-5 8.09, JAr-4,Ar-2/6 1.99/8.09, 1.99
JAr-5,Ar-4 8.09; JAr-5,Ar-6 7.93/8.09, 7.93
JAr-6,Ar-5 7.93; JAr-6,Ar-4/2 2.28/7.93, 2.29
was then screened against 60 cell lines of nine types of
human cancers: leukemia, lung, colon, CNS, melanoma,
ovarian, renal, prostate and breast at five different concentra-
tions. A 48 h continuous drug exposure protocol was used
with a sulforhodamine B (SRB) protein assay to estimate cell
viability or growth. Results (Table 7) are expressed as
log10GI50, which is the drug concentration (M) causing 50%
reduction in the net protein increase in control cells during
the drug incubation. This compound showed activity only at
higher concentration. Noteworthy results were obtained in
the case of non-small lung cancer (NCI-H226), melanoma
(SKMEL-28), and renal cancer (A-498) where the reduction
in growth was 75%, 97% and 84%, respectively, at the con-
centration of 1.0 × 10–4 M.
2.2.2. Antimicrobial activity
The in vitro antibacterial (S. aureus IOA-106, B. subtilis
MTCC-121 laboratory isolate, E. coli U.P-2566 and
P. aeruginosa IOA-110) and anti fungal (C. albicans SC-
5314 laboratory isolate) activities of the seven compounds
(2)–(8) were evaluated by agar well diffusion method. The
results for the antimicrobial study of the tested compounds
against the test organisms are depicted in Table 8. Antimicro-
bial activity against “Gram negative” bacteria was deduced

178
V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
Table 5
in all compounds. However, such activity could be detected
only in four compounds against “Gram positive” bacteria.
The compounds, (3), (4), (7) and (8) demonstrated overall
broad-spectrum antimicrobial activity, i.e. against both
“Gram negative” and “Gram positive” bacteria. Compound
(8) also demonstrated antifungal (anticandidal) activity. It is
interesting to note that the compound (7), which is a higher
homologue of (3) showed enhanced activity against all the
tested bacteria. Effective concentration of these active com-
pounds was 250 µg per well. Further exploration requires
detailed study on exact mode of interaction of these peculiar
compounds with “Gram negative” and “Gram positive” bac-
teria. In vivo protection and possible toxicity data on these
compounds are to be generated further.
13C-NMR data of (5)/(6) in acetone-d6
C number
2 (5)/(6)
4 (5)/(6)
5cis (5)/(6)
5trans (5)/(6)
5-CH3cis (5)/(6)
5-CH3trans (5)/(6)
1′ (5)/(6)
2′ (5)/(6)
3′ (5)/(6)
4′–8′ (5)
4′–10′ (6)
9′ (5)
d (ppm)
61.16/61.16
172.83/172.83
39.53/39.53
39.82/39.83
19.46/19.46
20.6/20.61
172.23/172.22
34.1 a/34.08
25.98/25.97
29.24–30.39
29.24–30.4
34.44 a
10′ (5)
139.88
11′ (5)/(6)
1″-CH3 (6)
1″ (6)
114.63/31.91
17.78
3. Conclusion
41.35
2″ (6)
174.33
In conclusion, the aim of the present research work was to
synthesize some novel long alkyl chain substituted
thiazolidin-4-ones/tetrahydro-1,3-thiazin-4-ones and to
evaluate their antitumor and antimicrobial activities. It has
been achieved by the synthesis of three novel thiazolidin-4-
ones (4), (5) and (6) and a novel tetrahydro-1,3-thiazin-4-one
(8), all bearing a long alkyl chain at 3-position. We have also
investigated the stereochemistry of long chain acyl hydra-
zones (2), (3) and (7). These were found to exist as syn-
periplanar and antiperiplanar conformers, the ratio of which
changes with the change in the polarity of the solvents. The
compound (5) showed significant cytotoxic activity in the
case of lung cancer, melanoma and renal cancer, where the
reduction in growth was found to be 75%, 97% and 84%,
respectively, at the concentration of 1.0 × 10–4 M. Com-
pounds (3), (4), (7) and (8) exhibited broad-spectrum antimi-
crobial activity. It is noteworthy that the compound (7), the
higher analogue of (3) showed enhanced activity against all
the tested bacteria. Further investigations for other biological
assays are required to explore their potentialities in future.
Ar-1cis (5)/(6)
Ar-1trans (5)/(6)
Ar-2 (5)/(6)
Ar-3 (5)/(6)
Ar-4 (5)/(6)
Ar-5 (5)/(6)
Ar-4 (5)/(6)
141.59/141.57
142.41/142.4
124.84/124.85
149.55/149.55
123.82/123.82
131.05/131.06
135.54/135.55
a Assignment may be reversed.
4. Experimental protocols
4.1. Chemistry
Reagents and solvents were of commercial grade and
were used without further purification. 10-Undecenoic acid
was also of commercial grade. Column chromatography was
performed on silica gel (60–120 mesh LR, 25049). Melting
points (m.p.) were determined on a Koffler hot-plate appara-
tus and are uncorrected. IR spectra were recorded on a
Perkin–Elmer 621 spectrophotometer using the KBr disc
Fig. 3
.
Table 6
Cytotoxic activity of the compounds against three cell lines of human
cancers
Test
Concen-
Retardation of growth (%)
MCF7 NCI-H460 SF-268
(Breast)
59
Activity
compounds tration
1
technique. H-NMR (d-ppm) spectra were recorded on a
(Lung)
95
(CNS)
107
65
(2)
(4)
(5)
(8)
1 × 10–4
1 × 10–4
1 × 10–4
1 × 10–4
Inactive
Inactive
Active
Varian Unity 400 spectrometer in acetone-d6 and DMSO-d6
with TMS as the internal standard. 13C-NMR spectra were
recorded on a Varian Unity 400 spectrometer at 100 MHz in
acetone-d6 and DMSO-d6. The splitting patterns of 1H-NMR
53
49
14
1
1
48
53
75
Inactive

V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
179
Table 7
Cytotoxic activity of compound (5) against 60 cell lines of human cancers
Type of cancer
Leukemia
Cell line
CCRF-CEM
HL-60 (TB)
K-562
MOLT-4
RPMI-8226
SR
A549/ATCC
EKVX
HOP-62
Concentration (M)
1.0 × 10–4
1.0 × 10–4
–
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
Log10GI50
–4.64
–4.32
–4.80
–4.78
–4.90
–5.64
–4.57
–4.42
–4.47
–4.77
–4.72
–4.63
–4.69
–4.61
–4.80
–4.52
–4.44
–4.23
–4.54
–4.75
–4.73
–4.38
–4.72
–4.75
–4.68
–4.63
–4.53
–4.71
–4.79
–4.72
–4.54
–4.55
–4.69
–4.73
–4.82
–4.91
–4.63
–4.73
–4.81
–4.53
–4.49
–4.28
–4.56
–4.76
–4.74
–4.72
–4.75
–4.74
–4.82
–4.75
–4.64
–4.66
–4.67
–4.77
–4.84
–4.75
–4.65
–4.79
–4.52
Retardation of growth (%)
–
–
–
7
–
39
–
–
Non-small cell
Lung cancer
–
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
8
HOP-92
39
75
24
54
12
54
–
25
–
–
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
SF-268
–
1.0 × 10–4
1.0 × 10–4
Colon cancer
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
57
41
–
CNS cancer
Melanoma
50
56
51
57
67
48
46
61
8
24
97
60
64
74
39
39
54
10
3
SF-295
SF-539
SNB-19
SNB-75
U251
LOX IMVI
MALME-3M
M14
–
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
IGROVI
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
SK-OV-3
786-0
A498
ACHN
CAKI-1
SN12C
TK-10
UO-31
PC-3
DU-145
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
Ovarian cancer
Renal cancer
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
1.0 × 10–4
–
1.0 × 10–4
–
–
11
84
48
24
72
65
70
16
37
29
27
56
54
67
35
59
13
Prostate cancer
Breast cancer
MCF7
NCI/ADR-RES
MDA-MB-231/ATCC
HS 578T
MDA-MB-435
MDA-N
–
1.0 × 10–4
–
–
BT-549
T-47D
1.0 × 10–4
1.0 × 10–4

180
V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
Table 8
Antimicrobial activity of some of the synthesized compounds by Agar well diffusion method
Test compounds
Effective concentration µg per well
Antimicrobial activity in terms of zone of inhibition in mm
SA
–
BS
–
EC
19
10
13
18
14
14
13
24
–
PA
–
CA
–
(2)
(3)
(4)
(5)
(6)
(7)
(8)
250
250
12
–
12
21
–
14
12
22
16
20
16
30
–
–
250
–
250
–
–
250
–
–
–
250
18
16
25
–
15
14
20
–
–
250
15
–
Chloram-phenicol
Fluconozole
100 µg per well
100 µg per well
25
SA, S. aureus; BS, B. subtilis; EC, E. coli; PA, P. aeruginosa; CA, C. albicans.
were designated as follows: s: singlet; d: doublet; t: triplet;
dd: double doublet; td: triplet doublet; tdd: triplet double
doublet; br s: broad singlet; br p: broad pentet; q: quartet; qd:
quartet doublet. DCI-mass spectra were recorded in a Riber-
mag RI0-10B quadrupole mass spectrometer using ammonia
as reagent gas.
4.1.3. ({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-oxo-
undecyl}sulfanyl)acetic acid (3) and [(11-{[2-(3-nitro-
phenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11-oxoundecyl)
sulfanyl]acetic acid (4) (reaction of (2)
with merceptoacetic acid)
To a solution of the precursor (2) (1.02 g, 3.0 mmol) in
anhydrous benzene (20.0 ml) was added mercaptoacetic acid
(832 mg, 9.0 mmol) and refluxed for 16 h with stirring at
80 °C, collecting the generated water in an azeotropic collec-
tor. The progress of the reaction was monitored (TLC) at
every 30 min. The reaction mixture was then worked up as
described for compound (2) and the orange oily residue left
was chromatographed over a silica gel column using pet.
ether (60–80 °C)–diethylether (1:1 v/v) as an eluent. Elution
of the column gave an orange solid, which on crystallization
from ethanol afforded (3) as crystalline yellow globules,
217 mg, (31.2%), m.p. = 120 °C, Rf = 0.43 (benzene–diethyl-
ether, 6:4 v/v).
4.1.1. 10-Undecenoic acid hydrazide (1)
Compound (1) was prepared from 10-undecenoic acid
according to the reported method [37] as white crystalline
globules in 84.0% yield, m.p. = 88 °C, Rf = 0.76 (benzene–
diethylether, 6:4 v/v). mmax 3425, 3300 (N–H), 2950, 2850
(C–H), 1630 (C=O), 1575 (C=C), 1530, 1460, 1440, 1380,
1190, 1160, 910 cm–1.
4.1.2. m-Nitrobenzaldehyde-10-undecenohydrazone (2)
A solution of (1) (4.0 g, 20.2 mmol) and m-nitro-
benzaldehyde (3.052 g, 20.2 mmol) in anhydrous benzene
(50.0 ml) was refluxed with stirring on an oil bath for 5 h,
collecting the generated water in an azeotropic collector. The
solution was then cooled, washed with water and the organic
phase was dried over Na2SO4. The solvent was distilled off
under diminished pressure and the product was crystallized
from ethanol to yield (2) as yellow crystalline needles, 5.81 g
(87.0%), m.p. = 128 °C, Rf = 0.7 (benzene–diethylether,
6:4 v/v).
mmax 3250 (N–H), 3075 (OH), 2900, 2850 (C–H), 1725
(COOH), 1645 (CO), 1610 (phenyl), 1555 (C=N), 1520
(NO2, asym. str.), 1350 (NO2, sym. str.), 1465 (S–CH2),
1400, 1380, 1190 cm–1; dH (acetone-d6): 8.18, 8.48 (~75%,
25%; 1H, s, H-7), 10.29, 10.66 (~75%, 25%; 1H, s, NH),
2.31, 2.74 (~25%, 75%; 2H, t, J = 7.48, 7.47, H-2′), 1.59 (2H,
br p, J ≈ 7.63, H-3′), 1.31 (12H, br s, H-4′–9′), 1.69 (2H, br p,
J ≈ 7.48, H-10′), 2.64 (2H, t, J = 7.32, H-11′), 3.22 (2H, s,
H-1″), 8.51 (1H, dd, J = 1.98, 1.83, Ar-2), 8.24 (1H, dd,
J = 7.93, 1.98, Ar-4), 7.73 (1H, dd, J = 7.94, 7.93, Ar-5), 8.14
(1H, dd, J = 7.94, 1.98, Ar-6); dH (DMSO-d6): 8.07, 8.27
(~60%, 40%; 1H, s, H-7), 11.39, 11.53 (~60%, 40%; 1H, s,
NH), 2.21, 2.62 (~40%, 60%; 2H, t, J = 7.33, 7.51, H-2′),
1.48 (2H, br p, J = 7.50, H-3′), 1.58 (2H, br p, J ≈ 7.14,
H-10′), 1.25 (12H, br s, H-4′–9′), 2.54 (2H, t, J = 6.78,
H-11′), 3.17 (2H, s, H-1″), 8.45 (1H, dd, J = 1.99, 1.83,Ar-2),
8.21 (1H, dd, J = 8.05, 1.83, Ar-4), 7.70 (1H, dd, J = 8.05,
7.69, Ar-5), 8.07 (1H, dd, J = 7.69, 1.82, Ar-6); dC (DMSO-
d6): 139.99, 143.24 (~60%, 40%; C-7), 168.95, 174.57
(~40%, 60%; C-1′), 31.76, 34.12 (~60%, 40%; C-2′), 24.17
(C-3′), 28.04–28.79 (C-4′–10′) 31.67 (C-11′), 171.47 (C-2″),
33.2 (C-1″), 136.18 (Ar–C-1), 120.51 (Ar–C-2), 148.18 (Ar–
C-3), 123.7 (Ar–C-4), 130.3 (Ar–C-5), 132.6 (Ar–C-6).
DCI-MS (NH3); m/z (%): 424 [(M + 1)+, 50.9] 425 (28.6),
mmax 3100 (N–H), 2950, 2850 (C–H), 1660, 1640 (C=O),
1580 (phenyl, C=C), 1550 (C=N), 1510 (NO2, asym. str.),
1330 (NO2, sym. str.), 1420, 1255, 1225, 1150, 1100, 1055,
970, 935, 885, 810, 790, 715 cm–1; dH (DMSO-d6): 8.09,
8.50 (~60%, 40%; 1H, s, H-7), 11.41, 11.54 (~60%, 40%;
1H, s, NH), 2.22, 2.64 (~40%, 60%; 2H, t, J = 7.5, 7.69,
H-2′), 1.6 (2H, br p, J = 7.14; H-3′), 1.28 (10H, br s, H-4′–8′),
2.0 (2H, td, J = 7.14, 6.60, H-9′), 5.76 (1H, tdd, J = 6.77,
17.22, 10.26, H-10′), 4.93 (1H, dd, J = 10.26, 2.01, HE), 5.00
(1H, dd, J = 17.22, 2.01, HZ), 8.47 (1H, dd, J = 2.02, 2.03,
Ar-2), 8.26 (1H, dd, J = 8.23, 2.02, Ar-4), 7.72 (1H, dd,
J = 7.51, 8.23, Ar-5), 8.09 (1H, d, J = 7.51, Ar-6); The dH and
dC (acetone-d6) values are given in Tables 1,2; DCI-MS
(NH3); m/z (%): 332 [(M + 1), 100.0], 333 (48.0), 334 (19.0),
335 (7.0), 316 (6.4), 317 (3.6), 165 (5.0), 149 (4.4), 118 (4.0),
59 (3.8).

V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
181
426 (10.2), 336 (10.6), 337 (4.2), 275 (3.8), 276 (52), 218
(5.8), 215 (4.3), 163 [(M+) – C13H23O2S, 11.8], 149 (36.7),
150 (10.2), 165 (9.4), 166 (10.0), 167 (4.8), 147 (11.0), 148
[(M+) – C13H25NO3S, 10.0], 149 (36.7), 150 (10.2), 136
(16.6), 137 (5.3), 133 (9.8), 134 [(M + 1) – C15H20N3O3,
58.8], 121 (9.5), 118 [M+ – C16H23N3O3, 13.0], 119 (6.3).
(4.1), 149 (26.9), 150 (5.3), 151 (4.1), 137 (4.5), 130 (16.5),
131 (3.7), 121 (6.2), 116 (4.5), 117 (3.3), 118 (7.8), 110 (5.3),
105 (3.3), 107 (4.5), 95 (4.9), 94 (3.3), 93 (6.2), 91 (3.3), 89
(7.4), 87 (7.4), 85 (24.0), 83 (6.2), 82 (3.3), 81 (14.9), 80
(3.7), 76 (31.1), 74 (21.1), 72 (10.3), 71 (4.1); and (6) as pale
yellow oily liquid, 528 mg, (34.5%), Rf = 0.32 (benzene–
diethylether, 6:4 v/v). mmax 3200 (N–H), 3000 (OH), 2900,
2850 (C–H), 1700 (COOH), 1680 (CON), 1650 (CONH),
1600 (phenyl), 1520 (NO2 asym. str.), 1350 (NO2, sym. str.),
1420 (S–CH2), 1360, 1210, 1125 cm–1. The dH and dC values
are given in Tables 4,5. DCI-MS (NH3); m/z (%): 525 [(M +
1)+, C24H35N3O6S2, 22.0], 526 (98.6), 527 (31.0), 524 (58.6),
543 [(M + 18)+, 31.7], 544 (8.9), 541 (8.9), 480 [(M+) –
COOH, 15.0], 471 (9.8), 454 (9.6), 436 (8.2), 419 [(M + 1)+
– SCH(CH3)COOH, 17.2], 405 (7.2), 308 [(M+) –
(C12H23O2S, 17.2], 290 [(M + 1)+ – C10H8N2O3S, 33.1], 289
(9.2), 288 (10.4), 280 [(M+) – C13H25O2S, 10.0], 273 [(M+) –
C10H10N3O3S, 9.6], 271 (9.4), 237 [(M+) – C14H26NO3S,
100.0], 238 (15.8), 239 (10.3), 229 (14.6), 218 (15.8), 207
(37.2), 199 (20.0), 184 (17.9), 180 (18.6), 164 (15.2), 165
(15.0), 166 (15.5), 151 (14.9), 147 (22.7), 138 (28.9), 130
(20.6), 121 (17.9), 108 (15.2), 87 (17.2), 75 (16.5).
Further elution of the column yielded (4) as a yellow oily
liquid, 810 mg (54.0%), Rf = 0.38 (benzene–diethylether,
6:4 v/v). mmax 3250 (N–H), 3050 (OH), 2900, 2850 (C–H),
1725 (COOH), 1685 (CON), 1660 (CONH), 1610 (phenyl),
1525 (NO2 asym. str.), 1355 (NO2, sym. str.), 1430 (S–CH2),
1405, 1260, 1165 cm–1; The dH and dC values are given in
Table 3. DCI-MS (NH3) m/z (%): 498 [(M + 1)+, 14.5], 499
(10.1), 452 [(M+) – CO2H, 10.2], 424 [(M + 1)+ – SCH2CO,
10.4], 425 (4.8), 332 (9.5), 273 (10.4), 274 (7.6), 275 (13.6),
276 [(M + 1)+ – C9H7N2O3S, 72.2], 277 (31.3), 278 (14.0),
258 [(M + 1)+ – C9H9N3O3S, 10.0], 239 (7.2), 240 [(M + 1)+
– C13H22O3S, 91.8], 241 (35.9), 242 (11.8), 230 (10.9), 231
[(M+) – C8H9N3O2S, 25.4], 232 (16.3), 223 [(M+) –
C13H24NO9S, 27.2], 224 (12.2), 210 [(M + 1)+
–
C13H24N2O3S, 39.5], 212 (24.0), 213 (13.1) 214 (6.4), 215
[(M+) – C13H24NO3S, 47.7], 216 (22.2), 217 (8.1), 218
(14.5), 193 (25.0), 194 (12.2), 195 (29.5), 196 (11.3), 176
(11.8), 178 (12.7), 162 (8.1), 163 (8.2), 164 (8.1), 165 (7.9),
166 (40.4), 148 (15.0), 149 (10.0), 150 (9.0), 151 (15.4), 152
(16.3), 153 (7.5), 134 (42.2), 135 (20.0), 136 (32.2), 137
(19.0), 138 (30.0), 139 (18.1), 118 (32.2), 119 (9.5), 110
(8.2), 81 (13.1), 82 (9.0), 83 (14.5), 87 (11.8), 89 (10.4), 91
(12.7), 93 (13.6), 94 (29.0), 95 (17.7), 96 (8.4), 97 (8.6), 99
(20.0), 100 (9.5).
4.1.5. 3-({11-[(2E)-2-(3-nitrobenzylidene)hydrazino]-11-
oxoundecyl}sulfanyl)propanoic acid (7) and
3-[(11-{[2-(3-nitrophenyl)-4-oxo-1,3-thiazinan-3-
yl]amino}-11-oxoundecenyl)sulfanyl]propanoic acid (8)
(reaction of (2) with 3-mercaptopropionic acid)
To a solution of (2) (1.02 g, 3.0 mmol) in anhydrous
benzene (20.0 ml) was added 3-mercaptopropionic acid
(961 mg, 9.0 mmol) and refluxed for 26 h as mentioned above
and then worked up as usual. The products on column chro-
matography (pet. ether (60–80 °C)–diethylether, 1:1 v/v)
yielded a yellow solid and an orange oily liquid. The former
on crystallization (benzene–acetone) afforded (7) as white
crystalline globules, 765 mg (58.0%), m.p. = 98 °C, Rf = 0.46
(benzene–diethylether, 6:4 v/v).
4.1.4. N-[5-methyl-2-(3-nitrophenyl)-4-oxo-1,3-thiazolidin-
3-yl]undec-10-enamide (5) and 2-[(11-{[5-methyl-2-
(3-nitrophenyl)-4-oxo-1,3-thiazolidin-3-yl]amino}-11-
oxoundecyl)sulfanyl]propanoic acid (6) (reaction of (2)
with 2-mercaptopropionic acid)
To a solution of (2) (1.01 g, 3.0 mmol) in anhydrous
benzene (20.0 ml) was added 2-mercaptopropionic acid
(961 mg, 9.0 mmol) and refluxed for 22 h as mentioned
above. The reaction mixture was worked up as usual and the
residue on purification by column chromatography (pet.
ether (60–80 °C)–diethylether, 4:6 v/v) yielded two liquid
compounds (5) as a colorless oily liquid, 536 mg (42.3%),
Rf = 0.46 (benzene–diethylether, 6:4 v/v).
mmax 3175 (N–H), 3040 (OH), 2900, 2800 (C–H), 1730
(COOH), 1645 (CONH), 1605 (phenyl), 1555 (C=N), 1520
(NO2), asym. str.), 1480 (S–CH2), 1340 (NO2, sym. str.),
1415, 1380, 1215, 1110, 800 cm–1; dH (acetone-d6): 8.18,
8.48 (~75%, 25%; 1H, s, H-7), 10.3, 10.66 (~75%, 25%; 1H,
s, NH), 2.31, 2.73 (~25%, 75%; 2H, t, J = 7.48, 7.31, H-2′),
1.56 (2H, br p, J ≈ 7.33, H-3′), 1.31 (12H, br s, H-4′–9′), 1.69
(2H, br p, J ≈ 7.33, H-10′), 2.55 (2H, t, J = 7.33, H-11′), 2.74
(2H, t, J = 7.17, H-1″), 2.57 (2H, t, J = 7.17, H-2″), 12.2 (1H,
br s, COOH), 8.51 (1H, dd, J = 1.99, 1.68, Ar-2), 8.24 (1H,
dd, J = 7.63, 1.83, Ar-4), 7.73 (1H, dd, J = 7.94, 7.63, Ar-5)
8.14 (1H, dd, J = 7.94, 1.98,Ar-6); dH (DMSO-d6): 8.11, 8.29
(~60%, 40%; 1H, s, H-7), 11.41, 11.55 (~60%, 40%; 1H, s,
NH), 2.23, 2.63 (~40%, 60%; 2H, t, J = 7.33, H-2′), 1.48 (2H,
br p, J ≈ 7.33, H-3′), 1.26 (12H, br s, H-4′–9′), 1.59 (2H, br p,
J ≈ 7.14, H-10′), 2.47 (2H, t, J = 7.14, H-11′), 2.65 (2H, t,
J = 6.77, H-1″), 2.49 (2H, t, J = 6.78, H-2″), 8.47 (1H, dd
, J = 1.99, 1.83,Ar-2), 8.23 (1H, dd, J = 8.05, 2.01,Ar-4) 7.72
(1H, dd, J = 7.88, 8.05, Ar-5), 8.08 (1H, dd, J = 7.88, 2.01,
mmax 3200 (N–H), 2900, 2850 (C–H), 1670 (CON), 1650
(CONH), 1580 (phenyl, C=C), 1510 (NO2 asym. str.), 1340
(NO2, sym. str.), 1410 (S–CH), 1380, 1250, 1180 cm–1. The
dH and dC values are given in Tables 4,5. DCI-MS (NH3); m/z
(%): 420 [(M + 1)+, C21H29N3O4S, 82.1], 421 (36.0), 422
(26.9), 437 [(M + 18)+, 6.6], 438 (3.7), 387 (9.1), 332 [(M +
18)+ – C3H4OS, 8.7], 313 (9.1), 266 (4.9), 254 [(M + 1)+ –
C11H19O, 82.1], 255 (13.6), 256 (4.9), 237 [(M + 1)+
–
C11H20NO, 100.0], 238 (20.7), 239 (7.8), 218 (4.1), 209
(3.3), 207 (4.5), 184 (11.6), 185 (6.6), 186 (3.3), 165 (7.0),
166 (8.7), 167 (60.5), 168 (9.1), 169 (3.3), 147 (21.9), 148

182
V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
Ar-6); dC (DMSO-d6): 139.97, 143.22 (~60%, 40%; C-7),
168.92, 174.55 (~40%, 60%; C-1′), 31.75, 34.11 (~60%,
40%; C-2′), 24.16 (C-3′), 28.40–28.80 (C-4′–10′), 31.00
(C-11′), 34.53 (C-2″), 26.35 (C-1″), 178.50 (C-3″), 136.17
(Ar–C-1), 120.50 (Ar–C-2), 148.18 (Ar–C-3), 123.69 (Ar–
C-4), 130.28 (Ar–C-5), 132.61 (Ar–C-6). DCI-MS (NH3);
m/z (%): 438 [(M + 1)+, C21H31N3O5S, 63.5], 439 (41.7), 440
(16.5), 366 (8.2), 336 (24.6), 337 (13.0), 304 [(M+) –
C5H9O2S, 14.2], 305 (8.0), 218 [(M+) – C12H13O2S, 25.9],
219 (10.0), 220 (7.4), 201 (8.4), 186 [(M+) – C12H12N3O3,
18.8), 187 (9.0), 163 (8.2), 164 (9.0), 165 (7.8), 166 (10.6),
148 [(M+) – C15H20N3O3, 24.8], 149 (16.4), 150 (15.2), 151
(15.2), 152 (7.8), 133 (23.6), 134 [(M + 1)+ – C16H23N3O3,
100.0], 135 (67.0), 136 (38.7), 137 (16.8), 118 (37.7), 119
(18.2), 120 (26.3), 121 (88.3), 122 (35.1), 123 (15.4), 106
(11.4), 107 (11.0), 108 (13.6), 109 (7.8), 94 (9.2), 72 (21.0),
73 (9.0) and the latter on further purification by silica gel
column gave (8) as a yellow oily liquid, 412 mg, (26.0%),
Rf = 0.24 (benzene–diethylether, 6:4 v/v).
experiment, cells were inoculated into 96-well microtiter
plates in 100 µm at plating densities ranging from 5000 to
40,000 cells per well depending on the doubling time of
individual cell lines. After cell inoculation, the microtiter
plates were incubated at 37 °C with 5% CO2, 95% air and
100% relative humidity for 24 h prior to addition of experi-
mental drugs. After 24 h, two plates of each cell line were
fixed in situ with TCA, to represent a measurement of the cell
population for each cell line at the time of drug addition (Tz).
Experimental drugs were solubilized in dimethyl sulfoxide at
400-fold of the desired final maximum test concentration and
stored frozen prior to use. At the time of the drug addition, an
aliquot of frozen concentrate was thawed and diluted to twice
the desired final maximum test concentration with complete
medium containing 50 µg ml–1 gentamicin. Additional four,
10-fold or 1/2 log serial dilutions were made to provide a
total of five drug concentrations plus control. Aliquots of
100 µl of these different drug dilutions were added to the
appropriate microtiter wells already containing 100 µl of
medium, resulting in the required final drug concentrations.
mmax 3200 (NH), 3050 (OH), 2910, 2840 (C–H), 1710
(COOH), 1680 (CON), 1650 (CONH), 1610 (phenyl), 1525
(NO2 asym. str.), 1430 (S–CH2), 1375, 1350 (NO2 sym. str.),
1230, 1170, 1070, 800, 720 cm–1. DCI-MS (NH3); m/z: 526
[M + H]+; dH (acetone-d6); 6.14 (1H, s, H-2), 2.94 (2H, t, J
= 6.71, H-5) 3.1 (2H, t, J = 6.71, H-6), 9.12 (1H, s, NH), 2.09
(1H, t, J = poorly resolved, H-2′), 1.58 (2H, br p, J = 7.17,
H-3′) 1.29 (12H, m, H-4′–9′), 1.6 (2H, br p, J = poorly
resolved, H-10′), 2.56 (2H, t, J = 7.33, H-11′), 2.75 (2H, t,
J = 7.17, H-1″), 2.58 (2H, t, J = 7.17, H-2″), 8.28 (1H, dd,
J = 2.14, 1.83 Ar-2), 8.23 (1H, dd, J = 8.09, 2.29, Ar-4), 7.72
(1H, dd, J = 8.09, 7.93, Ar-5), 7.9 (1H, dd, J = 7.93, 1.07,
Ar-6); dC (acetone-d6): 66.02 (C-2), 173.14 (C-4), 37.24a
(C-5), 27.59b (C-6), 172.35 (C-1′), 34.13 (C-2′), 25.97 (C-
3′), 29.50–30.20 (C-4′–11′), 24.53b (C-1″), 35.25a (C-2″),
169.15 (C-3″), 141.89 (Ar–C-1), 122.94 (Ar–C-2), 149.36
(Ar–C-3), 124.17 (Ar–C-4), 130.76 (Ar–C-5), 134.65 (Ar–
Following drug addition, the plates were incubated for an
additional 48 h at 37 °C, 5% CO2, 95% air and 100% relative
humidity. For adherent cells, the assay was terminated by the
addition of cold TCA. Cells were fixed in situ by the gentle
addition of 50 µl of cold 50% (w/v) TCA (final concentration,
10% TCA) and incubated for 60 min at 4 °C. The supernatant
was discarded, and the plates were washed five times with tap
water and air-dried. SRB solution (100 µl) at 0.4% (w/v) in
1% acetic acid was added to each well, and plates were
incubated for 10 min at room temperature. After staining,
unbound dye was removed by washing five times with 1%
acetic acid and the plates were air-dried. Bound stain was
subsequently solubilized with 10 mM trizma base, and the
absorbance was read on an automated plate reader at a wave-
length of 515 nm. For suspension cells, the methodology was
the same except that the assay was terminated by fixing
settled cells at the bottom of the wells by gently adding 50 µl
of 80% TCA (final concentration, 16% TCA). Using the
seven absorbance measurements (time zero (Tz), control
growth (C), and test growth in the presence of drug at the five
concentration levels (Ti)), the percentage growth was calcu-
lated at each of the drug concentrations levels. Percentage
growth inhibition was calculated as:
C-6). DCI-MS (NH3); m/z (%): 526 [(M
+
1)+,
C24H35N3O6S2, 18.8], 527 (9.3), 438 [(M + 1)+
–
CO(CH2)2S, 41.2], 439 (15.6), 440 (6.0), 420 (10.5), 406
(4.6), 341 [(M+) – C8H7NO2S, 100.0], 342 (31.7), 343 (10.2),
290 (13.8), 254 [(M + 1)+ – C14H25O3S, 27.0], 255 (9.0), 237
[(M+) – C14H26NO3S, 71.4], 238 (15.1), 239 (9.5), 220
(76.1), 221 (16.5), 166 (25.3), 167 (17.5), 150 (15.7), 138
(11.4), 120 (11.4), 121 (33.1), 123 (23.8), 118 (9.1), 93
(12.1), 87 (17.2), 89 (14.0), 81 (12.5), 77 (9.3), 72 (15.5).
[(Ti – Tz)/(C – Tz)] × 100 for concentration for which Ti ≥
Tz;
Ti – Tz/Tz × 100 for concentrations for which Ti < Tz.
4.2. Cytotoxic activity against malignant human tumor
cells
Three dose response parameters were calculated for each
experimental agent. Growth inhibition of 50% (GI50) was
calculated from [(Ti – Tz)/(C – Tz)] × 100 = 50, which was
the drug concentration resulting in a 50% reduction in the net
protein increase (as measured by SRB staining) in control
cells during the drug incubation. The drug concentration
resulting in total growth inhibition (TGI) was calculated
from Ti = Tz. Values were calculated for each of these
parameters if the level of activity was reached; however, if
The human tumor cell lines of the cancer-screening panel
were grown in RPMI 1640 medium containing 5% fetal
bovine serum and 2 mM L-glutamine. For a typical screening
a Assignment may be reversed.
b Assignment may be reversed.

V.P.M. Rahman et al. / European Journal of Medicinal Chemistry 40 (2005) 173–184
183
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We thank Professor Kabiruddin, Chairman, Aligarh Mus-
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are very grateful to Dr. V.L. Narayanan and all the staff
members of the National Cancer Institute, MD, USA for
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