Synthesis of 2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio]-N- (thiazole-2-yl)acetamide derivatives and their anticancer activities

Article abstract of DOI:10.1007/s00044-012-0411-5

In this work, 2-(4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio)-N- (thiazol-2-yl) acetamide derivatives were synthesized by reacting 4,5-dimethyl-1-(phenylamino)-1H-imidazole-2(3H)-thione derivatives with some 2-chloro-N-(thiazol-2-yl)acetamide compou

Full text of DOI:10.1007/s00044-012-0411-5

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2013) 22:4110–4124
DOI 10.1007/s00044-012-0411-5
ORIGINAL RESEARCH
Synthesis of 2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-
2-ylthio]-N-(thiazole-2-yl)acetamide derivatives and their
anticancer activities
•
Murat Duran S¸eref Demirayak
Received: 19 August 2012 / Accepted: 8 December 2012 / Published online: 21 December 2012
Ó Springer Science+Business Media New York 2012
Abstract In this work, 2-(4,5-dimethyl-1-(phenylamino)-
1H-imidazol-2-ylthio)-N-(thiazol-2-yl)acetamide derivatives
were synthesized by reacting 4,5-dimethyl-1-(phenylamino)-
1H-imidazole-2(3H)-thione derivatives with some 2-chloro-
N-(thiazol-2-yl)acetamide compounds. The structure of
synthesized compounds was confirmed by IR, 1H NMR, and
mass spectra. Anticancer activities of the compounds selected
by the National Cancer Institute were investigated by testing
against a panel of 60 different human tumor cell lines derived
from nine neoplastic cancer types. Compounds 7, 13, and 23
exhibited reasonable anticancer activity against the screened
cancer types with relatively low GI50 values. The compounds
showed high activity against melanoma-type cell lines.
United States. The early stage of melanoma can be cured
surgically. However, melanoma metastasizing to major
organs (stage IV) is virtually incurable (Park et al., 2011).
It is known that cytotoxic agents (classic specific purine
and pyrimidine bases or non-specific alkylation agents) are
conventionally employed in cancer therapy. Despite their
known and harshly criticized toxicity, these agents will be
used until less harmful drug alternatives are discovered.
Another limitation of the cancer therapy is the resistance,
which may be developed by tumor cells during clinical
treatment, against anticancer agents. Due to the above-
mentioned disadvantages of the drug therapies, research is
focused to obtain novel compounds for use in efficient
therapies of cancer which is the most frightening disease
(Adjei and Buolamwini, 2006). Such research includes
targeting cancer-specific proteins acting by different
mechanisms.
Keywords Imidazole ꢀ Thiazole ꢀ Anticancer ꢀ
Melanoma ꢀ Acetamide
A literature review of new anticancer agents showed that
imidazole (Lagoja et al., 2003) and thiazole (Barone et al.,
1979) derivatives are important research topics in medici-
nal chemistry. In general, imidazole derivatives are known
to possess a diverse range of pharmacological activity.
Imidazole ring is the part of some antitumor drugs such as
dacarbazine [(5-(3,3-dimethyl-1-triazenyl)imidazole-4-car-
boxylic acid amide] and imuran [6-(1-methyl-4-nitroimi-
dazolyl-thio)-purine] as well the tumor growth inhibiting
Introduction
Cancer is a disease of uncontrolled mitosis, which results in
cells that grow and divide beyond the normal limits.
Cancer is a major cause of deaths all around the world. The
World Health Organization projected twelve million deaths
by cancer with existing therapeutics by 2030 (Kumar et al.,
2011). Additionally, melanoma is the most aggressive form
of the skin cancer and is the fastest growing cancer in the
cyclocreatine
(l-carboxymethyl-2-iminoimidazolidine)
(Krezel, 1998). In particular, compounds including imid-
azole and 2-acetylaminothiazole moiety have been widely
investigated for a range of pharmacological activities such
as anti-inflammatory (Geronikaki et al., 2003; Tseng et al.,
2009), antimicrobial (Bellina et al., 2007; Bondock et al.,
2010), antifungal (Bujdakova and Muckova, 1994; El-
Sharief and Moussa, 2009), anticonvulsant (Rostom et al.,
2009; Siddiqui and Ahsan, 2010), antiarrhythmic
M. Duran (&)
Department of Chemistry, Faculty of Arts & Sciences, Eskis¸ehir
Osmangazi University, 26480 Eskisehir, Turkey
e-mail: mduran@ogu.edu.tr
S¸. Demirayak
Department of Pharmaceutical Chemistry, Faculty of Pharmacy,
Medipol University, 34083 Istanbul, Turkey
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4111
(Amr et al., 2009; Grover and Dhein, 2001), neuroprotec-
tive (Graczyk et al., 2005; Milhaud et al., 2000), antidia-
betic (Crane et al., 2006), and antiproliferative (Luzina and
Popov, 2009; Bolos et al., 2002).
checked by TLC in 1:1 ethanol/EtOAc. After the solvent
was removed under reduced pressure, water (100 mL) and
brine were added to the residue. The mixture was filtered
off and dried in air. The solid was dissolved in ethanol and
activated charcoal was added to the solution and then
boiled. After filtering off the charcoal by filter paper, the
residue was purified by recrystallization from ethanol and a
(70–81 %) yield was obtained for 1–32.
In order to extend our previous study related to synthesis and
anticancer activities of some benzimidazole compounds
(Demirayak et al., 2011), we attempted to prepare a new
imidazole-based compound that has a potential anticancer
effect. For this purpose, 32 derivatives of 2-(4,5-dimethyl-1-
(phenylamino)-1H-imidazol-2-ylthio)-N-(thiazol-2-yl)acet-
amide structure were synthesized and their anticancer
activities were evaluated on the potential cancer agents.
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-
ylthio]-N-(thiazol-2-yl)acetamide 1
67 % yield; mp 224–225 °C (dec); IR mmax (KBr)/cm-1
3278 (N–H), 1682 (C=O), 1576 (C=C), 1128 (C–N), 583
(Ar–S); dH (400.13 MHz) (DMSO-d6) 12.79 (1H, s, N–H),
9.16 (1H, s, N–H), 7.48 (1H, d, J = 3.57 Hz, thiazole
C4–H), 7.23 (1H, d, J = 3.53 Hz, thiazole C5–H), 7.19
(2H, t, J = 7.92 Hz, phenyl C3–H, C5–H), 6.83 (1H, t,
J = 3.72 Hz, phenyl C4–H), 6.45 (2H, d, J = 8.40 Hz,
phenyl C2–H, C6–H), 4.12 (2H, s, S–CH2–), 2.08 (3H, s,
imidazole C5–CH3), 1.91 (3H, s, imidazole C4–CH3); MS
(FAB) [M ? 1]?: m/z 360; For C16H17N5OS2 calculated:
53.46 % C, 4.77 % H, 19.48 % N; found: 53.23 % C,
4.43 % H, 19.81 % N.
Experimental
Chemistry
Melting points (°C, uncorrected) of the synthesized com-
pounds were determined using the Electrothermal melting
1
point apparatus. H NMR spectra were recorded with a
BRUKER DPX-400, 400.13 MHz high performance digital
FT-NMR spectrometer, in DMSO-d6 solvent including
TMS as an internal standard. Coupling constants (J) are
reported as Hertz. IR spectra were obtained in KBr pressed
pellets via Bruker Tensor 27 FT-IR spectrometer. Mass
spectra fast atom bombardment (FAB) was obtained on a
VG Quattro mass spectrometer. Elemental analyses were
performed on a Perkin Elmer EAL 240 elemental analyzer.
The purities of compounds were checked by TLC on silica
gel 60 F254. Starting materials were either commercially
available or synthesized according to the methods given in
the literature.
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-
ylthio]-N-(4-methylthiazol-2-yl)acetamide 2
75 % yield; mp 119–120 °C; IR mmax (KBr)/cm-1 3488
(N–H), 1671 (C=O), 1601 (C=C), 1128 (C–N), 603 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.68 (1H, s, N–H), 9.15
(1H, s, N–H), 7.21 (2H, t, J = 7.94 Hz, phenyl C3–H, C5–
H), 6.83 (1H, t, J = 3.80 Hz, phenyl C4–H), 6.77 (1H, s,
thiazole C5–H), 6.45 (2H, d, J = 8.32 Hz, phenyl C2–H,
C6–H), 4.10 (2H, s, S–CH2–), 2.26 (3H, s, thiazole CH3),
2.07 (3H, s, imidazole C5–CH3), 1.91 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 375; For C17H19N5OS2
calculated: 54.67 % C, 5.13 % H, 18.75 % N; found:
54.90 % C, 5.45 % H, 18.74 % N.
Methods of preparation of compounds 2-chloro-N-
(thiazol-2-yl)acetamides (2a–h) and 4,5-dimethyl-1-
(phenylamino)-1H-imidazole-2(3H)-thiones (3a–d)
Starting materials 1a–h and 2a–h were prepared according
to the method described by (Zav’yalov et al., 2007; Koti
et al., 2007) and (Singh et al., 2010), respectively. Syn-
thesis of imidazole derivatives (3a–d) was achieved using
the method described by (Schantl and Lagoja, 1997).
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-
ylthio]-N-(4-nitrothiazol-2-yl)acetamide 3
Synthesis procedure of compounds 2-[4,5-dimethyl-1-
(phenylamino)-1H-imidazol-2-ylthio]-N-(thiazole-2-
yl)acetamides (1–32)
84 % yield; mp 165–167 °C; IR mmax (KBr)/cm-1 3335
(N–H), 1687 (C=O), 1601 (C=C), 1182 (C–N), 585 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.66 (1H, s, N–H), 9.14
(1H, s, N–H), 8.64 (1H, s, thiazole C4–H), 7.20 (2H, t,
J = 7.94 Hz, phenyl C3–H, C5–H), 6.84 (1H, t,
J = 4.11 Hz, phenyl C4–H), 6.45 (2H, d, J = 8.30 Hz,
phenyl C2–H, C6–H), 4.11 (2H, s, S–CH2–), 2.09 (3H, s,
imidazole C5–CH3), 1.90 (3H, s, imidazole C4–CH3); MS
(FAB) [M ? 1]?: m/z 405; For C16H16N6O3S2 calculated:
Equimolar quantities of 2a–h (3 mmol) in acetone (30 mL)
and equimolar potassium carbonate were mixed and fol-
lowed by the addition of equimolar 4,5-dimethyl-1-(phe-
nylamino)-1H-imidazole-2(3H)-thione derivatives (3a–d).
The solution was stirred at room temperature for 24 h and
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N-[4-(4-chlorophenyl)thiazol-2-yl]-2-(4,5-dimethyl-1-
47.51 % C, 3.99 % H, 20.78 % N; found: 47.86 % C,
3.72 % H, 20.39 % N.
(phenylamino)-1H-imidazol-2-ylthio]acetamide 7
56 % yield; mp 192–193 °C; IR mmax (KBr)/cm-1 3248
(N–H), 1677 (C=O), 1574 (C=C), 1133 (C–N), 600 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.81 (1H, s, N–H), 9.15
(1H, s, N–H), 7.92 (2H, d, J = 8.60 Hz, phenyl C02–H, C60 –
H), 7.72 (1H, s, thiazole C5–H), 7.50 (2H, d, J = 6.92 Hz,
phenyl C03–H, C50 –H), 7.20 (2H, t, J = 7.92 Hz, phenyl C3–
H, C5–H), 6.84 (1H, t, J = 3.68 Hz, phenyl C4–H), 6.45
(2H, d, J = 7.64 Hz, phenyl C2–H, C6–H), 4.07 (2H, s, S–
CH2–), 2.09 (3H, s, imidazole C5–CH3), 1.91 (3H, s,
imidazole C4–CH3); MS (FAB) [M ? 1]?: m/z 471; For
C22H20ClN5OS2 calculated: 56.22 % C, 4.29 % H,
14.90 % N; found: 55.94 % C, 4.45 % H, 15.15 % N.
Ethyl 2-[2-(4,5-dimethyl-1-(phenylamino)-1H-imidazol-
2-ylthio)acetamido]thiazole-4-carboxylate 4
63 % yield; mp 159–160 °C; IR mmax (KBr)/cm-1 3357
(N–H), 1721 (C=O), 1675 (C=C), 1142 (C–N), 600 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.81 (1H, s, N–H), 9.78
(1H, s, N–H), 8.06 (1H, s, thiazole C5–H), 7.20 (2H, t,
J = 7.92 Hz, phenyl C3–H, C5–H), 6.84 (1H, t,
J = 4.00 Hz, phenyl C4–H), 6.45 (2H, d, J = 8.20 Hz,
phenyl C2–H, C6–H), 4.28 (2H, q, J = 7.00 Hz,
–CH2CH3), 4.07 (2H, s, S–CH2–), 2.09 (3H, s, imidazole
C5–CH3), 1.90 (3H, s, imidazole C4–CH3), 1.30 (3H, t,
J = 7.00 Hz, –CH2CH3); MS (FAB) [M ? 1]?: m/z 433;
For C19H21N5O3S2 calculated: 52.88 % C, 4.91 % H,
16.23 % N; found: 52.94 % C, 5.06 % H, 16.37 % N.
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio]-
N-(4,5,6,7-tetrahydrobenzo[d]thiazol-2-yl)acetamide 8
63 % yield; mp 164–166 °C; IR mmax (KBr)/cm-1 3334
(N–H), 1678 (C=O), 1610 (C=C), 1126 (C–N), 576 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.80 (1H, s, N–H), 9.17
(1H, s, N–H), 7.20 (2H, t, J = 8.00 Hz, C3–H, C5–H), 6.84
(1H, t, J = 4.00 Hz, phenyl C4–H), 6.46 (2H, d,
J = 8.00 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–),
2.64 (2H, s, –CH2–), 2.54 (2H, s, –CH2–), 2.06 (3H, s,
imidazole C5–CH3), 1.89 (3H, s, imidazole C4–CH3), 1.76
(4H, s, –CH2–CH2–); MS (FAB) [M ? 1]?: m/z 415; For
C20H23N5OS2 calculated: 58.08 % C, 5.61 % H, 16.93 %
N; found: 58.42 % C, 5.59 % H, 16.82 % N.
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio]-
N-(4-phenylthiazol-2-yl)acetamide 5
78 % yield; mp 171–172 °C; IR mmax (KBr)/cm-1 3254
(N–H), 1677 (C=O), 1600 (C=C), 1135 (C–N), 597 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.78 (1H, s, N–H), 9.15
(1H, s, N–H), 7.92 (2H, d, J = 7.50 Hz, phenyl C02–H C60 –
H), 7.65 (1H, s, thiazole C5–H), 7.45 (2H, t, J = 7.60 Hz,
phenyl C03–H, C50 –H), 7.35 (1H, t, J = 7.32 Hz, phenyl C04–
H), 7.20 (2H, t, J = 7.93 Hz, phenyl C3–H, C5–H), 6.84
(1H, t, J = 4.10 Hz, phenyl C4–H), 6.45 (2H, d,
J = 8.10 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–),
2.07 (3H, s, imidazole C5–CH3), 1.89 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 437; For C22H21N5OS2
calculated: 60.66 % C, 4.86 % H, 16.08 % N; found:
60.89 % C, 4.59 % H, 15.83 % N.
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-
ylthio]-N-(thiazol-2-yl)acetamide 9
54 % yield; mp 183–184 °C; IR mmax (KBr)/cm-1 3334
(N–H), 1680 (C=O), 1609 (C=C), 1138 (C–N), 587 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.28 (1H, s, N–H), 8.99
(1H, s, N–H), 7.48 (1H, d, J = 3.55 Hz, thiazole C4–H),
7.22 (1H, d, J = 3.51 Hz, thiazole C5–H), 6.99 (2H, d,
J = 8.27 Hz, phenyl C3–H, C5–H), 6.36 (2H, d, J =
8.23 Hz, phenyl C2–H, C6–H), 4.11 (2H, s, S–CH2–), 2.16
(3H, s, phenyl CH3), 2.09 (3H, s, imidazole C5–CH3), 1.90
(3H, s, imidazole C4–CH3); MS (FAB) [M ? 1]?: m/z 375;
For C17H19N5OS2 calculated: 54.67 % C, 5.13 % H,
18.75 % N; found: 54.93 % C, 5.24 % H, 18.92 % N.
2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio]-
N-(4-(4-methoxyphenyl)thiazol-2-yl)acetamide 6
53 % yield; mp 167–168 °C; IR mmax (KBr)/cm-1 3262
(N–H), 1674 (C=O), 1555 (C=C), 1127 (C–N), 600 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.56 (1H, s, N–H), 9.15
(1H, s, N–H), 7.84 (2H, d, J = 8.84 Hz, phenyl C02–H, C60 –
H), 7.47 (1H, s, thiazole C5–H), 7.20 (2H, t, J = 7.94 Hz,
phenyl C3–H, C5–H), 7.00 (2H, d, J = 8.92 Hz, phenyl
C03–H, C50 –H), 6.83 (1H, t, J = 4.89 Hz, phenyl C4–H),
6.46 (2H, d, J = 8.52 Hz, phenyl C2–H, C6–H), 4.06 (2H,
s, S–CH2–), 3.79 (3H, s, phenyl OCH3), 2.10 (3H, s,
imidazole C5–CH3), 1.91 (3H, s, imidazole C4–CH3); MS
(FAB) [M ? 1]?: m/z 467; For C23H23N5O2S2 calculated:
59.33 % C, 4.98 % H, 15.04 % N; found: 59.34 % C,
4.78 % H, 15.35 % N.
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-ylthio]-
N-(4-methylthiazol-2-yl)acetamide 10
78 % yield; mp 186–187 °C; IR mmax (KBr)/cm-1 3319
(N–H), 1667 (C=O), 1616 (C=C), 1134 (C–N), 586 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.77 (1H, s, N–H), 9.00
(1H, s, N–H), 7.00 (2H, d, J = 8.20 Hz, phenyl C3–H,
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C5–H), 6.77 (1H, s, thiazole C5–H), 6.35 (2H, d,
J = 8.28 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–),
2.26 (3H, s, thiazole CH3), 2.16 (3H, s, phenyl CH3), 2.10
(3H, s, imidazole C5–CH3), 1.90 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 389; For C18H21N5OS2
calculated: 55.79 % C, 5.46 % H, 18.07 % N; found:
55.41 % C, 5.28 % H, 18.47 % N.
C5–CH3), 1.90 (3H, s, imidazole C4–CH3); MS (FAB)
[M ? 1]?: m/z 451; For C23H23N5OS2 calculated: 61.44 %
C, 5.16 % H, 15.58 % N; found: 61.34 % C, 5.28 % H,
15.27 % N.
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-ylthio]-
N-(4-(4-methoxyphenyl)thiazol-2-yl)acetamide 14
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-
72 % yield; mp 162–164 °C; IR mmax (KBr)/cm-1 3253
(N–H), 1681 (C=O), 1613 (C=C), 1130 (C–N), 604 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.81 (1H, s, N–H), 8.98
(1H, s, N–H), Ar–H), 7.84 (2H, d, J = 8.80 Hz, phenyl
C02–H C06–H), 7.47 (1H, s, thiazole C5–H), 7.01 (4H, d,
J = 9.00 Hz, phenyl C03–H, C50 –H and C3–H, C5–H), 6.35
(2H, d, J = 8.32 Hz, phenyl C2–H, C6–H), 4.07 (2H, s, S–
CH2–), 3.79 (3H, s, phenyl OCH3), 2.17 (3H, s, imidazole
C5–CH3), 2.09 (3H, s, phenyl CH3), 1.91 (3H, s, imidazole
C4–CH3); MS (FAB) [M ? 1]?: m/z 481; For C24H25N5
O2S2 calculated: 60.10 % C, 5.25 % H, 14.60 % N; found:
60.04 % C, 5.04 % H, 14.82 % N.
ylthio]-N-(4-nitrothiazol-2-yl)acetamide 11
82 % yield; mp 187 °C (dec); IR mmax (KBr)/cm-1 3328
(N–H), 1717 (C=O), 1572 (C=C), 1124 (C–N), 624 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.78 (1H, s, N–H), 9.01
(1H, s, N–H), 8.65 (1H, s, thiazole C4–H), 7.00 (2H, d,
J = 8.38 Hz, phenyl C3–H, C5–H), 6.36 (2H, d,
J = 8.28 Hz, phenyl C2–H, C6–H), 4.11 (2H, s, S–CH2–),
2.17 (3H, s, phenyl CH3), 2.08 (3H, s, imidazole C5–CH3),
1.91 (3H, s, imidazole C4–CH3); MS (FAB) [M ? 1]?:
m/z 420; For C17H18N6O3S2 calculated: 48.79 % C, 4.34 %
H, 20.08 % N; found: 48.90 % C, 4.52 % H, 19.69 % N.
N-[4-(4-chlorophenyl)thiazol-2-yl)-2-(4,5-dimethyl-
Ethyl 2-[2-(4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-
1-(p-tolylamino)-1H-imidazol-2-ylthio]acetamide 15
2-ylthio)acetamido]thiazole-4-carboxylate 12
62 % yield; mp 194–195 °C; IR mmax (KBr)/cm-1 3356
(N–H), 1678 (C=O), 1615 (C=C), 1133 (C–N), 603 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.80 (1H, s, N–H), 8.97
(1H, s, N–H), 7.93 (2H, d, J = 8.59 Hz, phenyl C02–H, C60 –
H), 7.72 (1H, s, thiazole C5–H), 7.51 (2H, d, J = 7.00 Hz,
phenyl C03–H, C05–H), 6.99 (2H, d, J = 8.23 Hz, phenyl
C3–H, C5–H), 6.35 (2H, d, J = 8.18 Hz, phenyl C2–H, C6–
H), 4.07 (2H, s, S–CH2–), 2.16 (3H, s, phenyl CH3), 2.09
(3H, s, imidazole C5–CH3), 1.90 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 485; For C23H22ClN5OS2
calculated: 57.07 % C, 4.58 % H, 14.47 % N; found:
56.88 % C, 4.52 % H, 14.38 % N.
59 % yield; mp 189–190 °C; IR mmax (KBr)/cm-1 3438
(N–H), 1686 (C=O), 1614 (C=C), 1144 (C–N), 636 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.80 (1H, s, N–H), 8.96
(1H, s, N–H), 8.06 (1H, s, thiazole C5–H), 7.00 (2H, d,
J = 8.28 Hz, phenyl C3–H, C5–H), 6.36 (2H, d,
J = 8.35 Hz, phenyl C2–H, C6–H), 4.09 (2H, s, S–CH2–),
4.28 (2H, q, J = 7.12 Hz, –CH2CH3), 2.17 (3H, s, phenyl
CH3), 2.07 (3H, s, imidazole C5–CH3), 1.89 (3H, s, imid-
azole C4–CH3), 1.30 (3H, t, J = 7.12 Hz, –CH2CH3); MS
(FAB) [M ? 1]?: m/z 447; For C20H23N5O3S2 calculated:
53.91 % C, 5.20 % H, 15.72 % N; found: 53.69 % C,
5.37 % H, 15.88 % N.
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-ylthio]-
2-[4,5-dimethyl-1-(p-tolylamino)-1H-imidazol-2-ylthio]-
N-(4,5,6,7-tetrahydrobenzo[d]thiazol-2-yl)acetamide 16
N-(4-phenylthiazol-2-yl)acetamide 13
62 % yield; mp 198–199 °C; IR mmax (KBr)/cm-1 3326
(N–H), 1673 (C=O), 1564 (C=C), 1137 (C–N), 585 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.27 (1H, s, N–H), 8.97
(1H, s, N–H), 6.99 (2H, d, J = 8.28 Hz, phenyl C3–H, C5–
H), 6.35 (2H, d, J = 8.40 Hz, phenyl C2–H, C6–H), 4.00
(2H, s, S–CH2–), 2.63 (2H, s, –CH2–), 2.55 (2H, s, –CH2–),
2.18 (3H, s, phenyl CH3), 2.06 (3H, s, imidazole C5–CH3),
1.89 (3H, s, imidazole C4–CH3), 1.77 (4H, s, –CH2–CH2–);
MS (FAB) [M ? 1]?: m/z 429; For C21H25N5OS2 calcu-
lated: 58.99 % C, 5.89 % H, 16.38 % N; found: 59.04 %
C, 6.06 % H, 16.58 % N.
63 % yield; mp 185–186 °C; IR mmax (KBr)/cm-1 3262
(N–H), 1677 (C=O), 1615 (C=C), 1135 (C–N), 598 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.80 (1H, s, N–H), 8.99
(1H, s, N–H), 7.91 (2H, d, J = 7.64 Hz, phenyl C02–H C60 –
H), 7.65 (1H, s, thiazole C5–H), 7.44 (2H, t, J = 7.62 Hz,
phenyl C03–H, C50 –H), 7.34 (1H, t, J = 7.30 Hz, phenyl C04–
H), 7.00 (2H, d, J = 8.20 Hz, phenyl C3–H, C5–H), 6.36
(2H, d, J = 8.28 Hz, phenyl C2–H, C6–H), 4.05 (2H, s, S–
CH2–), 2.17 (3H, s, phenyl CH3), 2.10 (3H, s, imidazole
123

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Med Chem Res (2013) 22:4110–4124
2-[1-(4-methoxyphenylamino)-4,5-dimethyl-1H-imidazol-
J = 8.94 Hz, phenyl C3–H, C5–H), 6.43 (2H, d,
J = 8.90 Hz, phenyl C2–H, C6–H), 4.28 (2H, q, J =
7.10 Hz, –CH2CH3), 4.09 (2H, s, S–CH2–), 3.65 (3H, s,
phenyl OCH3), 2.10 (3H, s, imidazole C5–CH3), 1.90 (3H,
s, imidazole C4–CH3), 1.30 (3H, t, J = 7.10 Hz, –CH2
CH3); MS (FAB) [M ? 1]?: m/z 463; For C20H23
N5O4S2 calculated: 52.04 % C, 5.02 % H, 15.17 % N;
found: 52.35 % C, 5.07 % H, 14.91 % N.
2-ylthio]-N-(thiazol-2-yl)acetamide 17
48 % yield; mp 129–130 °C; IR mmax (KBr)/cm-1 3227
(N–H), 1682 (C=O), 1607 (C=C), 1134 (C–N), 591 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.05 (1H, s, N–H), 8.85
(1H, s, N–H), 7.48 (1H, d, J = 3.56 Hz, thiazole C4–H),
7.23 (1H, d, J = 3.52 Hz, thiazole C5–H), 6.80 (2H, d,
J = 8.92 Hz, phenyl C3–H, C5–H), 6.43 (2H, d,
J = 8.92 Hz, phenyl C2–H, C6–H), 4.05 (2H, s, S–CH2–),
3.66 (3H, s, phenyl OCH3), 2.07 (3H, s, imidazole C5–
CH3), 1.92 (3H, s, imidazole C4–CH3); MS (FAB)
[M ? 1]?: m/z 391; For C17H19N5O2S2 calculated:
52.42 % C, 4.92 % H, 17.98 % N; found: 52.79 % C,
5.03 % H, 18.02 % N.
2-[1-(4-methoxyphenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4-phenylthiazol-2-yl)acetamide 21
69 % yield; mp 183–184 °C; IR mmax (KBr)/cm-1 3253
(N–H), 1678 (C=O), 1555 (C=C), 1135 (C–N), 602 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.47 (1H, s, N–H), 8.85
(1H, s, N–H), 7.91 (2H, d, J = 7.44 Hz, phenyl C02–H C60 –
H), 7.65 (1H, s, thiazole C5–H), 7.43 (2H, t, J = 7.80 Hz,
phenyl C03–H, C50 –H), 7.33 (1H, t, J = 7.34 Hz, phenyl C04–
H), 6.80 (2H, d, J = 8.88 Hz, phenyl C3–H, C5–H), 6.43
(2H, d, J = 8.88 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–
CH2–), 3.65 (3H, s, phenyl OCH3), 2.09 (3H, s, imidazole
C5–CH3), 1.90 (3H, s, imidazole C4–CH3); MS (FAB)
[M ? 1]?: m/z 467; For C23H23N5O2S2 calculated:
59.33 % C, 4.98 % H, 15.04 % N; found: 58.97 % C,
4.71 % H, 15.37 % N.
2-[1-(4-methoxyphenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4-methylthiazol-2-yl)acetamide 18
79 % yield; mp 180–181 °C; IR mmax (KBr)/cm-1 3320
(N–H), 1668 (C=O), 1610 (C=C), 1136 (C–N), 589 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.47 (1H, s, N–H), 8.85
(1H, s, N–H), 6.81 (2H, d, J = 8.85 Hz, phenyl C3–H, C5–
H), 6.77 (1H, s, thiazole C5–H), 6.43 (2H, d, J = 8.90 Hz,
phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–), 3.65 (3H, s,
phenyl OCH3), 2.25 (3H, s, thiazole CH3), 2.09 (3H, s,
imidazole C5–CH3), 1.92 (3H, s, imidazole C4–CH3); MS
(FAB) [M ? 1]?: m/z 405; For C18H21N5O2S2 calculated:
53.58 % C, 5.25 % H, 17.36 % N; found: 53.67 % C,
5.01 % H, 17.11 % N.
N-[4-(4-methoxyphenyl)thiazol-2-yl]-2-[1-(4-
methoxyphenylamino)-4,5-dimethyl-1H-imidazol-2-
ylthio]acetamide 22
80 % yield; mp 164–165 °C; IR mmax (KBr)/cm-1 3246
(N–H), 1682 (C=O), 1612 (C=C), 1131 (C–N), 605 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.30 (1H, s, N–H), 8.88
(1H, s, N–H), 7.84 (2H, d, J = 8.85 Hz, phenyl C02–H C60 –
H), 7.47 (1H, s, thiazole C5–H), 6.99 (2H, d, J = 8.89 Hz,
phenyl C03–H, C05–H), 6.80 (2H, d, J = 8.93 Hz, phenyl
C3–H, C5–H), 6.43 (2H, d, J = 8.93 Hz, phenyl C2–H, C6–
H), 4.09 (2H, s, S–CH2–), 3.79 (3H, s, phenyl OCH3), 3.65
(3H, s, phenyl OCH3), 2.08 (3H, s, imidazole C5–CH3),
1.89 (3H, s, imidazole C4–CH3); MS (FAB) [M ? 1]?: m/
z 497; For C24H25N5O3S2 calculated: 58.16 % C, 5.08 %
H, 14.13 % N; found: 57.97 % C, 4.92 % H, 14.10 % N.
2-[1-(4-methoxyphenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4-nitrothiazol-2-yl)acetamide 19
81 % yield; mp 148–149 °C; IR mmax (KBr)/cm-1 3296
(N–H), 1700 (C=O), 1570 (C=C), 1123 (C–N), 600 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.25 (1H, s, N–H), 8.88
(1H, s, N–H), 8.65 (1H, s, thiazole C4–H), 6.80 (2H, d,
J = 8.96 Hz, phenyl C3–H, C5–H), 6.42 (2H, d,
J = 8.92 Hz, phenyl C2–H, C6–H), 4.12 (2H, s, S–CH2–),
3.66 (3H, s, phenyl OCH3), 2.04 (3H, s, imidazole C5–
CH3), 1.89 (3H, s, imidazole C4–CH3); MS (FAB)
[M ? 1]?: m/z 436; For C17H18N6O4S2 calculated:
46.99 % C, 4.18 % H, 19.34 % N; found: 46.84 % C,
3.97 % H, 19.47 % N.
N–[4-(4-chlorophenyl)thiazol-2-yl)-2-(1-(4-
methoxyphenylamino)-4,5-dimethyl-1H-imidazol-2-
ylthio]acetamide 23
Ethyl 2-[2-(1-(4-methoxyphenylamino)-4,5-dimethyl-1H-
39 % yield; mp 196–197 °C; IR mmax (KBr)/cm-1 3245
(N–H), 1679 (C=O), 1614 (C=C), 1134 (C–N), 605 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.45 (1H, s, N–H), 8.86
(1H, s, N–H), 7.93 (2H, d, J = 8.59 Hz, phenyl C02–H C60 –
H), 7.72 (1H, s, thiazole C5–H), 7.51 (2H, d, J = 6.72 Hz,
phenyl C03–H, C05–H), 6.80 (2H, d, J = 8.90 Hz, phenyl
imidazol-2-ylthio)acetamido]thiazole-4-carboxylate 20
66 % yield; mp 173–174 °C; IR mmax (KBr)/cm-1 3431
(N–H), 1727 (C=O), 1682 (C=C), 1141 (C–N), 604 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.46 (1H, s, N–H), 8.86
(1H, s, N–H), 8.05 (1H, s, thiazole C5–H), 6.80 (2H, d,
123

Med Chem Res (2013) 22:4110–4124
4115
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-2-
C3–H, C5–H), 6.42 (2H, d, J = 8.90 Hz, phenyl C2–H, C6–
H), 4.07 (2H, s, S–CH2–), 3.65 (3H, s, phenyl OCH3), 2.09
(3H, s, imidazole C5–CH3), 1.91 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 501; For C23H22ClN5
O2S2 calculated: 55.25 % C, 4.43 % H, 14.01 % N; found:
54.92 % C, 4.07 % H, 14.00 % N.
ylthio]-N-(4-nitrothiazol-2-yl)acetamide 27
87 % yield; mp 182–183 °C; IR mmax (KBr)/cm-1 3329
(N–H), 1688 (C=O), 1619 (C=C), 1132 (C–N), 581 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.51 (1H, s, N–H), 9.25
(1H, s, N–H), 8.65 (1H, s, thiazole C4–H), 7.24 (2H, d,
J = 8.87 Hz, phenyl C3–H, C5–H), 6.45 (2H, d,
J = 8.89 Hz, phenyl C2–H, C6–H), 4.12 (2H, s, S–CH2–),
2.04 (3H, s, imidazole C5–CH3), 1.89 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 440; For C16H15ClN6
O3S2 calculated: 43.78 % C, 3.44 % H, 19.15 % N; found:
43.43 % C, 3.61 % H, 19.02 % N.
2-[1-(4-methoxyphenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4,5,6,7-tetrahydrobenzo[d]thiazol-2-
yl)acetamide 24
66 % yield; mp 183–184 °C; IR mmax (KBr)/cm-1 3319
(N–H), 1672 (C=O), 1616 (C=C), 1138 (C–N), 590 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.07 (1H, s, N–H), 8.86
(1H, s, N–H), 6.80 (2H, d, J = 8.93 Hz, phenyl C3–H, C5–
H), 6.42 (2H, d, J = 8.93 Hz, phenyl C2–H, C6–H), 4.09
(2H, s, S–CH2–), 3.66 (3H, s, phenyl OCH3), 2.63 (2H,
s, –CH2–), 2.55 (2H, s, –CH2–), 2.07 (3H, s, imidazole C5–
CH3), 1.90 (3H, s, imidazole C4–CH3), 1.77 (4H, s, –CH2–
CH2–); MS (FAB) [M ? 1]?: m/z 445; For C21H25N5O2S2
calculated: 56.86 % C, 5.68 % H, 15.79 % N; found:
56.96 % C, 5.83 % H, 16.04 % N.
Ethyl 2-[2-(1-(4-chlorophenylamino)-4,5-dimethyl-1H-
imidazol-2-ylthio)acetamido]thiazole-4-carboxylate 28
32 % yield; mp 183–185 °C; IR mmax (KBr)/cm-1 3166
(N–H), 1728 (C=O), 1689 (C=C), 1144 (C–N), 571 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.48 (1H, s, N–H), 9.25
(1H, s, N–H), 8.05 (1H, s, thiazole C5–H), 7.24 (2H, d,
J = 8.87 Hz, phenyl C3–H, C5–H), 6.45 (2H, d,
J = 8.88 Hz, phenyl C2–H, C6–H), 4.28 (2H, q, J =
7.11 Hz, –CH2CH3), 4.09 (2H, s, –S–CH2–), 2.10 (3H, s,
imidazole C5–CH3), 1.90 (3H, s, imidazole C4–CH3), 1.30
(3H, t, J = 7.12 Hz, –CH2CH3); MS (FAB) [M ? 1]?: m/
z 467; For C19H20ClN5O3S2 calculated: 48.97 % C, 4.33 %
H, 15.03 % N; found: 48.78 % C, 4.67 % H, 15.19 % N.
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(thiazol-2-yl)acetamide 25
69 % yield; mp 185–186 °C; IR mmax (KBr)/cm-1 3271
(N–H), 1661 (C=O), 1615 (C=C), 1135 (C–N), 587 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.56 (1H, s, N–H), 9.40
(1H, s, N–H), 7.49 (1H, d, J = 3.54 Hz, thiazole C4–H),
7.23 (1H, d, J = 3.53 Hz, thiazole C5–H), 7.24 (2H, d,
J = 8.88 Hz, phenyl C3–H, C5–H), 6.44 (2H, d,
J = 8.87 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–),
2.10 (3H, s, imidazole C5–CH3), 1.91 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 395; For C16H16ClN5OS2
calculated: 48.79 % C, 4.09 % H, 17.78 % N; found:
48.72 % C, 4.36 % H, 17.77 % N.
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-2-
ylthio]-N-(4-phenylthiazol-2-yl)acetamide 29
83 % yield; mp 181–184 °C; IR mmax (KBr)/cm-1 3255
(N–H), 1680 (C=O), 1598 (C=C), 1134 (C–N), 593 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.50 (1H, s, N–H), 9.20
(1H, s, N–H), 7.91 (2H, d, J = 7.54 Hz, phenyl C02–H C60 –
H), 7.65 (1H, s, thiazole C5–H), 7.43 (2H, t, J = 7.65 Hz,
phenyl C03–H, C50 –H), 7.34 (1H, t, J = 7.35 Hz, phenyl C04–
H), 7.24 (2H, d, J = 8.89 Hz, phenyl C3–H, C5–H), 6.45
(2H, d, J = 8.88 Hz, phenyl C2–H, C6–H), 4.06 (2H, s, S–
CH2–), 2.09 (3H, s, imidazole C5–CH3), 1.90 (3H, s,
imidazole C4–CH3); MS (FAB) [M ? 1]?: m/z 471; For
C22H20ClN5OS2 calculated: 56.22 % C, 4.29 % H,
14.90 % N; found: 56.45 % C, 4.41 % H, 15.00 % N.
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4-methylthiazol-2-yl)acetamide 26
62 % yield; mp 201–203 °C; IR mmax (KBr)/cm-1 3314
(N–H), 1665 (C=O), 1619 (C=C), 1132 (C–N), 584 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.50 (1H, s, N–H), 9.30
(1H, s, N–H), 7.24 (2H, d, J = 8.87 Hz, phenyl C3–H, C5–
H), 6.78 (1H, s, thiazole C5–H), 6.45 (2H, d, J = 8.88 Hz,
phenyl C2–H, C6–H), 4.06 (2H, s, S–CH2–), 2.25 (3H, s,
thiazole CH3), 2.09 (3H, s, imidazole C5–CH3), 1.92 (3H,
s, imidazole C4–CH3); MS (FAB) [M ? 1]?: m/z 409; For
C17H18ClN5OS2 calculated: 50.05 % C, 4.45 % H,
17.17 % N; found: 50.15 % C, 4.69 % H, 17.18 % N.
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-2-
ylthio]-N-[4-(4-methoxyphenyl)thiazol-2-yl]acetamide 30
65 % yield; mp 209–211 °C; IR mmax (KBr)/cm-1 3351
(N–H), 1682 (C=O), 1609 (C=C), 1134 (C–N), 576 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.57 (1H, s, N–H), 9.32
(1H, s, N–H), 7.84 (2H, d, J = 8.86 Hz, phenyl C02–H C60 –
H), 7.47 (1H, s, thiazole C5–H), 7.24 (2H, d, J = 8.87 Hz,
123

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Med Chem Res (2013) 22:4110–4124
Antitumor screening
phenyl C3–H, C5–H), 7.00 (2H, d, J = 8.88 Hz, phenyl
C03–H, C50 –H), 6.45 (2H, d, J = 8.87 Hz, phenyl C2–H, C6–
H), 4.06 (2H, s, S–CH2–), 3.80 (3H, s, phenyl OCH3), 2.10
(3H, s, imidazole C5–CH3), 1.91 (3H, s, imidazole C4–
CH3); MS (FAB) [M ? 1]?: m/z 501; For
C23H22ClN5O2S2 calculated: 55.25 % C, 4.43 % H,
14.01 % N; found: 55.50 % C, 4.55 % H, 14.23 % N.
All the newly synthesized compounds (1–32) were
screened for their anticancer activity at the National
Institutes of Health (NIH, Bethesda, Maryland, USA) under
the National Cancer Institute (NCI) Drug Discovery Pro-
gram, according to the procedure suggested by Boyd
(1989; NCI, 2012).
The process utilized 60 different human tumor cell lines
of nine cancer types [(Monks et al., 1991), Leukemia (L),
Non-Small Cell Lung Cancer (NSCLC), Colon Cancer
(CC), Central Nervous System Cancer (CNSC), Melanoma
(M), Ovarian Cancer (OC), Renal Cancer (RC), Prostate
Cancer (PC), and Breast Cancer (BC)]. The process aimed
to identify growth inhibition or cell killing of particular
tumor cell lines by specific compounds.
N-[4-(4-chlorophenyl)thiazol-2-yl]-2-[1-(4-
chlorophenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]acetamide 31
63 % yield; mp 196–197 °C; IR mmax (KBr)/cm-1 3249
(N–H), 1678 (C=O), 1614 (C=C), 1133 (C–N), 601 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.81 (1H, s, N–H), 9.40
(1H, s, N–H), 7.92 (2H, d, J = 8.59 Hz, phenyl C02–H, C60 –
H), 7.72 (1H, s, thiazole C5–H), 7.50 (2H, d, J = 6.71 Hz,
phenyl C03–H, C05–H), 7.24 (2H, d, J = 8.86 Hz, phenyl
C3–H, C5–H), 6.45 (2H, d, J = 8.88 Hz, phenyl C2–H, C6–
H), 4.07 (2H, s, S–CH2–), 2.09 (3H, s, imidazole C5–CH3),
1.91 (3H, s, imidazole C4–CH3); MS (FAB) [M ? 1]?: m/
z 505; For C22H19Cl2N5OS2 calculated: 52.38 % C, 3.80 %
H, 13.88 % N; found: 52.75 % C, 3.94 % H, 14.07 % N.
Full panel and mean-graph midpoint values (MG-MID)
are given in Table 1. Results of each test agent are reported
as the percentage growth of the treated cells compared to
the untreated control cells. The compounds reducing the
growth of any cell up to 32 % or less (negative numbers
indicate the killing of the cell) passed the evaluation of 60
cell lines over a five-log dose range.
Three response parameters (GI50, TGI, and LC50) were
calculated for each cell line. The GI50 value (growth
inhibitory activity) corresponds to the concentration of the
compounds causing 50 % decrease in net cell growth;
the TGI value (cytostatic activity) is the concentration of
the compounds resulting in total growth inhibition; and the
LC50 value (cytotoxic activity) is the concentration of the
compounds causing net 50 % loss of initial cells at the end
of the incubation period (48 h). The presence of living cells
and their growth were evaluated spectrophotometrically
with the sulforhodamine (SRB) protein dye test and com-
pared with the standards (cisplatin and melphalan). The
screening results are presented in Table 2; positive values
under 100 describe growth inhibitory activity, while neg-
ative values indicate cytotoxic activity.
2-[1-(4-chlorophenylamino)-4,5-dimethyl-1H-imidazol-
2-ylthio]-N-(4,5,6,7-tetrahydrobenzo[d]thiazol-2-
yl)acetamide 32
42 % yield; mp 164–165 °C; IR mmax (KBr)/cm-1 3324
(N–H), 1671 (C=O), 1613 (C=C), 1139 (C–N), 582 (Ar–S);
dH (400.13 MHz) (DMSO-d6) 12.49 (1H, s, N–H), 9.33
(1H, s, N–H), 7.24 (2H, d, J = 8.87 Hz, phenyl C3–H, C5–
H), 6.45 (2H, d, J = 8.89 Hz, phenyl C2–H, C6–H), 4.07
(2H, s, S–CH2–), 2.63 (2H, s, –CH2–), 2.55 (2H, s, –CH2–),
2.06 (3H, s, imidazole C5–CH3), 1.89 (3H, s, imidazole C4–
CH3), 1.77 (4H, s, –CH2–CH2–); MS (FAB) [M ? 1]?:
m/z 449; For C20H22ClN5OS2 calculated: 53.62 % C, 4.95 %
H, 15.63 % N; found: 53.88 % C, 4.63 % H, 15.84 % N.
Table 1 The mean-graph midpoint values of growth % of tested compounds
Compd no.
L
NSCLC
CC
CNSC
M
OC
RC
97.10
PC
BC
MG-MID
1
101.62
30.83
72.46
57.05
101.09
34.75
108.56
99.43
44.37
79.73
59.18
107.00
59.42
106.99
105.14
53.90
86.25
67.09
105.40
52.82
111.36
96.05
43.04
77.46
60.57
101.76
61.42
103.72
101.39
49.46
78.94
55.05
104.89
55.66
108.37
102.48
50.33
85.20
61.59
102.78
60.31
105.76
104.96
62.27
98.63
77.60
107.46
57.66
113.18
100.33
41.38
83.08
43.96
102.12
50.16
105.43
100.60
47.36
79.89
59.88
103.63
55.12
106.75
7
51.97
71.63
12
13
17
23
25
67.42
100.98
55.80
101.78
Leukemia (L), Non-Small Cell Lung Cancer (NSCLC), Colon Cancer (CC), Central Nervous System Cancer (CNSC) Cancer, Melanoma (M),
Ovarian Cancer (OC), Renal Cancer (RC), Prostate Cancer (PC), and Breast Cancer (BC), Mean-graph midpoint (MG-MID)
123

Med Chem Res (2013) 22:4110–4124
4117
Table 2 60 human tumor cell lines’ anticancer screening data at single dose assay as percent cell growth promotion of selected compounds
Cell lines
Compound no.
1
7
12
13
17
23
25
L
CCRF-CEM
HL-60(TB)
K-562
102.19
96.52
NT
24.68
57.71
100.87
98.86
NT
99.59
42.07
27.56
41.02
NT
77.24
78.51
92.25
72.05
87.01
63.80
37.67
54.72
55.78
72.64
NT
95.84
112.86
117.57
104.54
120.95
101.35
108.49
100.95
100.20
99.68
26.88
36.10
35.70
40.30
MOLT-4
RPMI-8226
SR
100.89
102.22
104.00
12.66
NSCLC
A549/ATCC
EKVX
98.55
115.74
83.75
28.85
34.55
48.49
NT
82.13
99.66
63.23
44.51
70.72
74.71
97.18
109.11
76.30
46.29
49.68
67.17
59.94
46.34
39.38
96.01
78.13
49.70
104.98
108.98
106.40
117.01
105.15
106.56
110.58
108.22
95.16
44.00
41.94
100.44
38.65
60.46
31.88
111.90
39.32
66.22
101.96
123.20
88.30
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
CC
76.48
96.74
100.29
97.67
59.84
12.20
70.81
52.96
47.28
93.51
109.41
131.80
106.00
111.97
118.03
102.18
102.09
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
117.71
101.96
93.75
65.21
69.51
29.45
57.63
25.29
57.14
73.10
80.51
96.72
68.84
98.05
52.44
108.43
98.75
32.48
91.96
40.22
67.18
56.13
82.85
98.80
107.27
110.49
106.93
100.06
102.36
96.74
79.56
54.24
27.81
59.76
30.12
43.08
75.20
121.19
115.62
94.47
97.16
102.77
108.32
113.75
123.41
99.80
KM12
109.29
116.34
SW-620
CNSC
113.70
SF-268
106.58
86.60
56.40
31.02
35.42
59.64
39.12
36.61
102.22
53.71
73.62
75.40
83.76
76.07
81.68
46.10
73.68
74.35
38.33
49.30
103.59
91.49
66.13
43.89
79.14
79.24
56.63
43.51
112.74
97.66
SF-295
SF-539
86.84
101.05
109.69
100.22
104.49
90.10
SNB-19
SNB-75
U251
108.55
85.30
121.25
92.05
102.44
108.53
M
LOX IMVI
MALME-3M
M14
99.28
121.77
96.90
104.58
106.73
99.72
94.75
94.83
94.24
26.08
99.30
47.55
41.00
84.99
54.29
10.19
46.91
34.83
77.98
110.81
70.97
78.21
93.46
80.17
47.48
88.46
62.91
51.93
92.03
76.97
76.71
81.38
77.24
-66.75
54.08
51.82
105.40
119.70
107.71
97.68
38.91
99.15
62.46
50.36
90.48
82.63
-21.47
48.91
49.53
101.80
140.83
97.83
MDA-MB-435
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
OC
110.71
116.11
111.02
84.95
92.70
113.96
102.75
108.29
95.78
107.66
104.39
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
123.21
116.22
103.25
80.93
68.44
61.29
35.93
65.75
95.15
108.50
74.76
86.00
78.47
25.36
81.80
102.01
113.42
110.54
89.33
70.85
60.75
30.81
111.33
126.10
117.12
102.19
87.36
74.57
123

4118
Med Chem Res (2013) 22:4110–4124
Table 2 continued
Cell lines
Compound no.
1
7
12
82.64
13
55.49
17
23
25
OVCAR-8
NCI/ADR-RES
SK-OV-3
RC
95.17
96.10
31.91
20.41
68.56
103.25
92.35
43.88
23.11
81.45
104.90
100.18
102.45
70.04
90.71
34.40
69.62
102.50
108.56
786-0
103.46
101.70
95.27
54.27
74.31
49.37
36.74
72.14
39.25
56.83
32.86
83.82
90.47
76.52
80.52
38.47
62.75
77.84
62.65
82.27
92.54
60.88
53.60
61.47
64.31
72.70
51.58
100.29
99.48
59.54
69.49
52.04
34.44
NT
111.66
101.93
104.69
101.14
91.41
A498
ACHN
100.51
90.35
CAKI-1
RXF 393
SN12C
102.08
83.96
126.87
98.23
94.40
67.16
68.50
39.41
96.39
TK-10
111.75
84.18
105.37
86.71
120.55
86.43
UO-31
PC
PC-3
93.56
59.13
65.41
88.30
71.80
83.40
103.43
112.49
35.69
79.62
103.63
122.72
DU-145
BC
116.36
108.96
MCF7
98.76
95.50
27.14
48.83
70.58
54.00
26.64
21.05
80.14
62.50
139.32
91.44
57.89
67.17
24.07
46.00
105.97
63.51
6.48
102.31
105.41
109.70
105.55
94.87
16.16
79.71
86.14
53.32
39.43
26.17
104.33
98.69
MDA-MB-231/ATCC
HS 578T
BT-549
T-47D
115.31
96.32
121.05
111.12
91.74
90.52
MDA-MB-468
105.55
17.71
94.85
105.66
NT not tested
Cisplatin (cis-[PtCl2(NH3)2], cis-diamminedichloroplati-
num) is a widely used platinum-containing anticancer drug
´
(Bogdanovic et al., 2002). Melphalan is an alkylating agent that
compounds. The sharp, strong bands located between 1661 and
1728 cm-1 correspond to the characteristic C=O stretching
vibrations of the compounds. The bands at about 571–636 cm-1
represent the presence of Ar–S vibrations of all compounds.
is used extensively in the treatment of neoplastic diseases, such
as myeloma, chronic lymphocytic leukemia, and ovarian and
breast carcinomas, for several important chemotherapeutic
drugs (Dulik et al., 1986).
1
By means of H NMR spectra, the structures of the com-
pounds were confirmed. The –S–CH2– signals of all synthe-
sized compounds (1–32) were observed at 4.05–4.12 ppm.
Two N–H hydrogen signals of all compounds appeared at
8.85–9.78 (CO–NH) and 12.05–12.81 (NH–N) ppm. Peaks at
6.35–7.24 ppm were assigned to the characteristic para
hydrogens of benzene rings. The hydrogen atoms of the
phenyl groups attached to thiazole ring were given as C0x–H in
the explanation of the spectroscopic data. The singlet peaks of
the methyl groups at C4–CH3 and C5–CH3 positions on
imidazole rings were observed at about 1.89–1.92 and
2.04–2.10 ppm, respectively. Molecular ions detected by FAB
confirmed the molecular weights of the compounds. Ele-
mental analyses of all compounds gave satisfactory results.
Results and Discussion
Chemistry
Synthesis of 2-[4,5-dimethyl-1-(phenylamino)-1H-imidazol-
2-ylthio]-N-(thiazol-2-yl)acetamide derivatives (1–32) was
achieved by a sequence of reactions depicted in Figs. 1 and
2. The reaction of 2a–h thiazole compounds with a variety of
imidazole-2-thione derivatives (3a–d) gave the 1–32 deriv-
atives (Table 3) (Zhan et al., 2009). After the synthesis of
these compounds, they were recrystallized from ethanol to
investigate their anticancer activities.
Pharmacology
In the IR spectra, the bands at about 3166–3488 cm-1
The structures of the synthesized compounds (1–32) were
submitted for screening against the NCI-60 cell lines’
assigned to the N–H groups existed in all synthesized
123

Med Chem Res (2013) 22:4110–4124
4119
R1
Fig. 1 Preparation of 2-chloro-
N-(thiazol-2-yl)acetamides
(2a–h) and 4,5-dimethyl-1-
(phenylamino)-1H-imidazole-
2(3H)-thiones (3a–d), a EtOH,
D; b Et3N, THF, RT; c AcOH,
RT
R1
R2
O
S
a
N
+
NH2 NH2
R2
NH2
Br(Cl)
S
1a-h
R1
O
O
b
N
1a-h
+
Cl
Cl
R2
N
Cl
S
H
2a-h
H
N
H3C
S
N
H3C
H3C
O
NH
H3C
c
NH2
NH
+
+
NaSCN
R3
Cl
R3
3a-d
1a. R1=R2=H
1b. R1=CH3, R2=H
1e. R1= C6H5-, R2=H
1h. R1=R2=-(CH2)4-
3c. R3= OCH3
1c. R1=H, R2=NO2
1d. R1= COOC2H5, R2=H
1g. R1=4-Cl-C6H5-, R2=H
3b. R3= CH3
1f. R1=4-OCH3-C6H5-, R2=H
3a. R3=H
3d. R3= Cl
Fig. 2 Preparation of
compounds 1–32, d Acetone,
K2CO3, RT
H3C
N
S
O
R1
R2
d
N
N
S
H3C
2a-h
3a-d
+
HN
NH
1-32
R3
panel. Seven compounds (1 (NSC 751264), 7 (NSC
751265), 12 (NSC 751267), 13 (NSC 751269), 17 (NSC
751270), 23 (NSC 751271), 25 (NSC 751272)) of 32 were
initially accepted by the National Cancer Institute for
in vitro disease-oriented human cells screening panel assay
(NCI-60) (Grever et al., 1992) and their antitumor activi-
ties were investigated at a single concentration of 10-5 M.
Afterward, three compounds (7, 13, 23) of these seven
compounds were chosen for further investigation and tested
at 10-fold dilutions of five concentrations ranging from
10-4 to 10-8 M in order to obtain concentration - %
growth inhibition curves.
When the results in Table 1 are compared, it can be seen
that the compounds 7 and 23 exhibit a higher anticancer
effect than the other selected compounds (1, 12, 13, 17, and
25). It is worthwhile to note that compound 7 and 23 include
chlorine atom in their para-substituted positions of their
phenyl rings located to the 4th position of the thiazole ring.
As shown in Table 1, the percentage growth values of
compounds 7, 13, and 23 are 47.36 %, 59.88 %, and
123

4120
Med Chem Res (2013) 22:4110–4124
Formula (M.W.)
Table 3 2-[4,5-dimethyl-1-
(phenylamino)-1H-imidazol-2-
ylthio]-N-(thiazole-2-
Comp.
R1
R2
R3
1a
2
–H
–H
–H
–H
–H
–H
–H
–H
C16H17N5OS2 (359.48)
C17H19N5OS2 (373.51)
C16H16N6O3S2 (404.48)
C19H21N5O3S2 (431.53)
C22H21N5OS2 (435.58)
yl)acetamide and derivatives
–CH3
–H
–H
3
–NO2
–H
4
–COOC2H5
C6H5–
5
–H
6
4–OCH3–
C6H5–
–H
C23H23N5O2S2 (465.60)
7b
8
4–Cl–C6H5–
–(CH2)4–
–H
–H
–H
C22H20ClN5OS2 (470.02)
C20H23N5OS2 (413.57)
C17H19N5OS2 (373.51)
C18H21N5OS2 (387.53)
C17H18N6O3S2 (418.50)
C20H23N5O3S2 (445.57)
C23H23N5OS2 (449.60)
C24H25N5O2S2 (479.63)
–H
9
–H
–CH3
–CH3
–CH3
–CH3
–CH3
–CH3
10
11
12a
13b
14
–CH3
–H
–H
–NO2
–H
–COOC2H5
C6H5–
–H
4–OCH3–
C6H5–
–H
15
16
17a
18
19
20
21
22
4–Cl–C6H5–
–(CH2)4–
–H
–H
–CH3
C23H22ClN5OS2 (484.05)
C21H25N5OS2 (427.60)
C17H19N5O2S2 (389.50)
C18H21N5O2S2 (403.53)
C17H18N6O4S2 (434.50)
C20H23N5O4S2 (461.57)
C23H23N5O2S2 (465.60)
C24H25N5O3S2 (495.63)
–CH3
–H
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–OCH3
–CH3
–H
–H
–NO2
–H
–COOC2H5
C6H5–
–H
4–OCH3–
C6H5–
–H
23b
4–Cl–C6H5–
–H
–OCH3
C23H22ClN5O2S2
(500.05)
24
25a
26
27
–(CH2)4–
–H
–OCH3
–Cl
C21H25N5O2S2 (443.60)
C16H16ClN5OS2 (393.92)
C17H18ClN5OS2 (407.95)
–H
–CH3
–H
–H
–Cl
–NO2
–Cl
C16H15ClN6O3S2
(438.92)
28
–COOC2H5
–H
–Cl
C19H20ClN5O3S2
(465.99)
a
29
30
C6H5–
–H
–H
–Cl
–Cl
C22H20ClN5OS2 (470.02)
Selected compounds for
in vitro one dose (10-5 M) full
NCI 60 cell panel assay
4–OCH3–
C6H5–
C23H22ClN5O2S2
(500.05)
b
Selected compounds for
31
32
4–Cl–C6H5–
–H
–Cl
–Cl
C22H19Cl2N5OS2
(504.47)
in vitro five dose (10-4 to
10-8 M) full NCI 60 cell panel
assay
–(CH2)4–
C20H22ClN5OS2 (448.01)
55.12 %, respectively. Low percentage growth values are
observed for K-562, NCI-H23, HCT-116, HT29, SK-MEL-
5, OVCAR-4, NCI/ADR-RES, MCF7, T-47D, and MDA-
MB-468 type cell lines. These compounds were examined
using in vitro 5 dose full NCI 60 cell panel assay.
ring, apart from the others (7, 13, 23). On the other hand,
the highest cell inhibition (10.19 %) is observed for com-
pound 7 in the cancerous cell type melanoma SK-MEL-5 in
the single dose investigation. Compound 7 also exhibits the
highest activity in 14 subtypes of cancer, with a cell inhi-
bition value of up to 32 % (OVCAR-8 (31.91 %), SF-295
(31.02 %), HCT-116 (29.45 %), A549/ATCC (28.85 %),
K-562 (27.56 %), MCF7 (27.14), T-47D (26.64 %),
LOX IMVI (26.08 %), HT29 (25.29 %), MDA-MB-468
(21.05 %), NCI/ADR-RES (20.41 %), SR (12.66 %),
In primary single high dose studies, the compound 12
gives the highest activity (24.68 %) in the cancerous cell
type leukemia CCRF-CEM (Table 2). The high activity of
this compound may be attributed to the presence of an ester
group (-COOCH2CH5) on the 4th location of the thiazole
123

Med Chem Res (2013) 22:4110–4124
4121
NCI-H23 (12.20 %) and SK-MEL-5 (10.19 %)). Addition-
ally, compound 7 gives relatively low activity in renal- and
prostate-type cancerous cells, while it is not effective for
MALME-3M (99.30 %)-type Melanoma cancerous cells.
It is seen from Table 2 that the compound 13 presents
effective inhibition against five subtypes of melanoma,
ovarian, and breast cancer. It gives the highest activity for
melanoma SK-MEL-5-type cancerous cells with the value
of -66.75 % growth inhibitions. The anticancer activity
results of compound 13 for the above-mentioned sub-
types of cancer can be listed as follows: T-47D (6.48 %)
[MDA-MB-468 (17.71 %)[MCF7 (24.07 %)[OVCAR-
4 (25.36 %). Like other effective compounds, 13 contains a
phenyl group on the 4th location of thiazole ring and it can
be said that this compound is highly effective in breast
cancer.
Compound 23 demonstrated potent anticancer activities
against nine cancer cell lines. The highest activity (-1.47 %)
was observed for SK-MEL-5 cell line. Reasonable activity
results were observed for MCF7 (16.16 %), NCI/ADR-RES
(23.11 %), MDA-MB-468 (26.17 %), K-562 (26.88 %),
HCT-116 (27.81 %), HT29 (30.12 %), OVCAR-4 (30.81 %),
Table 4 NCI in vitro testing results of compounds 7, 13, and 23 at the five dose level in lM concentration
Cell lines
Compound no.
7
13
23
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
L
CCRF-CEM
HL-60(TB)
K-562
5.49
2.99
0.12
2.51
3.55
3.81
[100
[100
[100
9.94
[100
[100
[100
[100
[100
[100
NA
3.82
[100
1.58
2.54
5.80
7.02
[100
59.1
[100
[100
[100
[100
[100
[100
4.64
3.62
3.46
NA
39.1
[100
[100
[100
[100
[100
[100
[100
[100
[100
MOLT-4
RPMI-8226
SR
[100
[100
NA
NSCLC
A549/ATCC
EKVX
2.90
1.84
3.06
1.61
3.37
1.85
4.17
2.89
2.54
11.6
12.2
9.63
6.89
18.8
6.02
22.9
11.0
13.7
40.1
94.1
31.7
38.9
93.9
26.3
[100
82.1
66.5
3.03
1.39
18.4
NA
[100
5.61
[100
[100
[100
3.32
1.92
NA
[100
[100
[100
[100
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
CC
[100
2.42
3.26
1.53
[100
2.69
5.05
7.80
[100
[100
[100
[100
[100
[100
NA
[100
[100
[100
10.6
3.42
10.2
3.88
2.97
[100
[100
16.5
[100
[100
83.3
86.8
[100
[100
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
4.13
10.6
1.84
5.74
3.78
2.95
5.50
14.5
29.5
4.62
23.3
15.4
14.0
22.9
49.8
82.6
15.5
76.9
49.5
41.4
74.6
3.98
NA
34.4
[100
1.94
3.07
2.12
4.79
4.61
1.84
4.78
3.55
9.91
6.51
[100
[100
[100
[100
[100
[100
2.82
5.17
4.37
4.13
8.03
26.5
[100
28.2
[100
[100
[100
[100
[100
14.1
[100
50.4
KM12
19.1
11.1
SW-620
CNSC
[100
[100
SF-268
4.80
2.29
1.90
9.41
3.48
3.13
20.1
16.5
4.27
24.6
16.2
13.0
58.8
[100
9.64
61.7
49.3
41.4
9.10
1.06
4.68
7.49
2.81
4.50
[100
5.89
[100
[100
[100
[100
[100
[100
2.81
2.18
4.15
6.20
4.80
4.03
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
SF-295
SF-539
35.2
SNB-19
SNB-75
U251
[100
[100
[100
M
LOX IMVI
1.78
3.72
7.79
3.32
19.3
[100
3.02
44.2
[100
123

4122
Med Chem Res (2013) 22:4110–4124
Table 4 continued
Cell lines
Compound no.
7
13
23
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
MALME-3M
M14
10.8
3.69
3.25
10.1
10.1
2.24
3.07
3.09
37.6
16.0
21.8
27.6
24.6
6.31
17.0
16.1
[100
51.2
2.48
3.70
2.66
7.58
NA
13.6
48.6
9.54
35.3
[100
[100
[100
[100
2.90
3.02
3.22
15.7
18.0
1.41
2.97
3.62
[100
[100
[100
66.8
[100
[100
[100
[100
[100
7.96
MDA-MB-435
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
OC
[100
75.5
59.7
[100
3.35
25.8
2.00
2.12
3.15
5.72
9.29
23.8
[100
50.3
[100
[100
41.1
[100
[100
[100
[100
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
NCI/ADR-RES
SK-OV-3
RC
3.36
3.00
4.60
2.65
2.71
2.60
5.91
20.6
12.1
22.1
13.5
7.73
7.18
19.8
[100
36.2
[100
54.2
38.9
69.9
47.4
4.59
8.24
2.13
17.2
3.79
3.04
10.6
[100
[100
[100
[100
[100
22.2
[100
[100
[100
[100
[100
[100
[100
5.67
3.13
4.02
[100
4.82
2.89
4.24
[100
24.2
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
[100
786-0
3.60
2.24
3.67
3.93
2.97
2.38
3.65
3.59
13.7
10.5
14.1
22.6
7.33
10.1
13.8
37.7
38.9
35.8
51.5
[100
26.8
35.8
40.7
[100
4.41
17.4
4.06
1.86
NA
[100
[100
62.9
[100
[100
[100
99.3
3.46
2.22
2.27
2.16
3.53
2.30
14.8
2.62
18.2
56.5
8.76
[100
9.64
7.52
80.9
[100
[100
[100
[100
[100
[100
[100
[100
[100
A498
ACHN
CAKI-1
6.10
RXF 393
SN12C
3.20
18.9
2.89
14.2
63.0
TK-10
[100
[100
[100
[100
UO-31
PC
PC-3
2.34
5.64
11.0
18.7
38.4
45.4
NA
2.65
4.06
[100
[100
[100
[100
DU-145
9.75
64.6
[100
BC
MCF7
2.94
3.01
3.42
7.02
1.40
1.45
11.4
15.2
21.6
20.9
5.24
6.27
52.2
57.8
[100
51.8
34.6
40.4
NA
3.36
8.37
11.8
6.46
1.23
0.57
25.5
[100
[100
82.0
[100
[100
[100
[100
[100
[100
MDA-MB-231/ATCC
HS 578T
BT-549
3.34
3.41
3.18
1.85
1.70
[100
[100
14.1
[100
[100
94.7
T-47D
10.4
[100
[100
8.04
MDA-MB-468
6.67
7.73
NA not available
NCI-H23 (31.88 %) cell lines. Similar to compound 7, 23 has
a chlorine atom in its molecular structure. It shows low
activity against CNSC, RC, and PC and the lowest activity
against NSCLC (111.90 %).
Compounds 7 and 23 exhibited strong anticancer activity
against most of the tested cell lines derived from 9 different
human cancer types with GI50 values of 0.12–10.8 lM and
0.57–18.0 lM, respectively. On the other hand, compound
23 exhibited no activity even in the highest concentration
(100 lM) test against HL-60(TB), NCI-H322M, and OV-
CAR-5 subpanels of leukemia, non-small cell lung cancer,
and ovarian cancer, respectively. These results can be seen
from Table 4 as ‘‘[100.’’
It can be seen from Table 4 that three of the compounds
(7, 13, and 23) demonstrate higher inhibition than the
others. The common feature of these compounds is being
effective against melanoma SK-MEL-5-type cancerous
cells.
123

Med Chem Res (2013) 22:4110–4124
4123
Table 5 Comparison of compounds showing anticancer activity with melphalan and cisplatin
Compd no.
L
NSCLC
CC
CNSC
M
OC
RC
PC
3.99
BC
3.21
MG_MID
7
3.08
3.91
4.15
3.31
0.41
2.69
6.18
2.88
6.76
0.63
4.93
4.75
3.31
7.76
0.72
4.17
4.94
4.03
7.59
0.66
5.35
3.38
5.98
8.32
0.83
3.55
7.08
4.13
6.61
0.35
3.25
3.80
5.58
4.15
8.13
0.63
13
23
A
B
7.53
4.17
9.75
3.36
2.70
5.30
10.23
0.68
32.36
0.39
16.22
0.89
A melphalan, B cisplatin, L leukemia, NSCLC Non-small cell lung cancer, CC Colon cancer, CNSC central nervous system cancer, M melanoma,
OC ovarian cancer, RC renal cancer, PC prostate cancer, BC breast cancer, MG-MID mean-graph midpoint
A comparison of the results in Table 4 reveals that
compounds 7, 13, and 23 exhibit the most potent activities
against K-562 (0.12 lM) cell line of leukemia, SF-295
(1.06 lM) cell line of central nervous system cancer, and
MDA-MB-468 (0.57 lM) cell line of breast cancer,
respectively. The GI50 values of these compounds and
standards (melphalan and cisplatin) are in given in Table 5.
It can be noticed from the Table that the GI50 values of the
three compounds tested in this study are lower than that of
melphalan.
study is required in order to reveal the effect of chlorine
atom substitution to 2-, 3- positions of the phenyl ring or
di- and tri-chloro substitution of these compounds.
Conclusions
In the present paper, synthesis of novel 32 compounds was
achieved and 7 compounds among them were accepted by
the NCI for testing their anticancer activities. Three of the
selected compounds demonstrated higher antitumor activ-
ities than the others. In particular, the most effective com-
pound (13) showed selective activity against melanoma
cell lines (SK-MEL-5).
Structure activity relationship
The anticancer activity screening (Table 2) revealed that
the unsubstituted compound 1 did not exhibit any activity
against the growth of cancer cell lines. As it is known,
chlorine atom withdraws electron inductively and donates
electron mesomerically. In the case of Cl atom substitution
to the R3 position (compound 25), inhibition of cell lines
was not observed. In contrast to 25, substitution of para-
chlorophenyl to the R1 position (7 and 23) leads to an
increase in anticancer activity against all cell lines (except
RC and PC). If we take into consideration compounds 1
and 17, it might be said that the location of –H and –OCH3
groups to the R3 position of compound 7 and 23 does not
contribute to the anticancer activities of the compounds. In
order to find out which position exhibits potent activity,
compounds 1, 7 and 17, 23 should be compared. 1 and 7
have the same substituent (-H) on their R3 positions, while
17 and 23 have the same substituent (-OCH3) on their R3
locations. From here, we can conclude that substituents in
the R3 position are not effective in anticancer property and
the main activity of these compounds (7, 23) comes from
the presence of para-chlorophenyl groups.
Acknowledgments The authors would like to thank Eskis¸ehir Os-
mangazi University for support and the National Cancer Institute
(NCI), Bethesda, MD, USA, for in vitro screening of the compounds
in human cancer cell lines.
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