A facile synthesis of some 3-cyano-1,4,6-trisubstituted-2(1H)-pyridinones and their biological evaluation as anticancer agents

Article abstract of DOI:10.1007/s00044-010-9469-0

The synthesis of some new 3-cyano-1,4,6-trisubstituted-2(1H)-pyridinones supported with various pharmacophores and functionalities at positin-1 is described. The in vitro anticancer activity of 24 of the newly synthesized compounds was evaluated according to the protocol of the NCI in vitro disease-oriented human cells screening panel assay. The results revealed that five compounds 4a-c, 7b, and 12b were able to display moderate antitumor potential against some of the tested subpanel tumor cell lines at the GI50 and TGI levels, however, with marginal or no cytotoxic (LC₅₀) activity. The obtained data suggested that better antitumor activity was linked to derivatives with either 4-bromophenyl or 3,4-dimethoxyphenyl moieties, together with a 1-methyl-1H-pyrrol-2-yl counter part at positions 6 and 4, respectively. Consequently, he 3-cyano-4-(1-methyl-1H-pyrrol-2-yl)-6-(4- bromophenyl or 3,4-dimethoxyphenyl)-2(1H)-pyridinones 4a and 4b, could be considered as the most active members identified in this investigation as evidenced from their relative higher growth inhibitory (GI₅₀ (MG-MID) 77.6 and 67.6 μM, respectively) and cytostatic (TGI (MG-MID) 85.1 and 95.5 lM, respectively) activities, when compared with the substituted thiocarbamoyl analog 7b and the icyclic [1,2,4]triazolo[3,4-a]pyridine derivative 12b. Springer Science+Business Media, LLC 2010.

Full text of DOI:10.1007/s00044-010-9469-0

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2011) 20:1260–1272
DOI 10.1007/s00044-010-9469-0
ORIGINAL RESEARCH
A facile synthesis of some 3-cyano-1,4,6-trisubstituted-2(1H)-
pyridinones and their biological evaluation as anticancer agents
•
Sherif A. F. Rostom Hassan M. Faidallah
•
Mohammed S. Al-Saadi
Received: 24 January 2010 / Accepted: 7 October 2010 / Published online: 21 October 2010
Ó Springer Science+Business Media, LLC 2010
Abstract The synthesis of some new 3-cyano-1,4,
6-trisubstituted-2(1H)-pyridinones supported with various
pharmacophores and functionalities at positin-1 is descri-
bed. The in vitro anticancer activity of 24 of the newly
synthesized compounds was evaluated according to the
protocol of the NCI in vitro disease-oriented human cells
screening panel assay. The results revealed that five com-
pounds 4a–c, 7b, and 12b were able to display moderate
antitumor potential against some of the tested subpanel
tumor cell lines at the GI50 and TGI levels, however, with
marginal or no cytotoxic (LC50) activity. The obtained data
suggested that better antitumor activity was linked to
derivatives with either 4-bromophenyl or 3,4-dimethoxy-
phenyl moieties, together with a 1-methyl-1H-pyrrol-2-yl
counter part at positions 6 and 4, respectively. Conse-
quently, the 3-cyano-4-(1-methyl-1H-pyrrol-2-yl)-6-(4-
bromophenyl or 3,4-dimethoxyphenyl)-2(1H)-pyridinones
4a and 4b, could be considered as the most active members
identified in this investigation as evidenced from their
relative higher growth inhibitory (GI50 (MG-MID) 77.6
and 67.6 lM, respectively) and cytostatic (TGI (MG-MID)
85.1 and 95.5 lM, respectively) activities, when compared
with the substituted thiocarbamoyl analog 7b and the
bicyclic [1,2,4]triazolo[3,4-a]pyridine derivative 12b.
Keywords Synthesis Á Chalcones Á Pyridinones Á
Pyrrole Á Thiophene Á Anticancer activity
The worldwide-ongoing efforts of research on treatment of
malignancy are focused on the discovery of novel potent
and effective antineoplastic agents, particularly those
interacting with novel biological targets. Nevertheless, in
spite of the large number of available chemotherapeutic
agents, the medical need is still largely unmet due to many
factors among which the lack of selectivity of conventional
drugs leading to toxicity, the metastatic spreading, and the
intrinsic or acquired resistance to chemotherapy developed
after few therapeutic cycles (multi-drug resistance; MDR)
(Bran˜a and Ramos, 2001; Cozzi, 2003). At the same time,
random screening remains one of the essential means to
discover new structure leads with antineoplastic activity.
The National Cancer Institute (NCI), Bethesda, USA, is
still playing an articular role in this field, with special
emphasis on novel chemical structures that have not had
extensive clinical evaluation (Cocco et al., 2000). In this
respect, among the most important pharmacologically
active heterocycles, pyridine-containing compounds have
attracted much attention as versatile chemotherapeutic
agents owing to their reported potential antimicrobial
(Abdel-Aziz et al., 2005; Srivastava et al., 2007; Aridoss
et al., 2007), antitubercular (Mamolo et al., 1999; Ranft
et al., 1999), antiamoebic (Abid et al., 2005), antiparasitic
(Goebel et al., 2008), and antiviral activities (Dragovich
et al., 2002; Gudmundsson et al., 2005; Allen et al., 2006).
As far as the antineoplastic potential is concerned,
pyridine derivatives were reported to possess cytotoxic
S. A. F. Rostom (&)
Faculty of Pharmacy, Department of Pharmaceutical Chemistry,
King Abdulaziz University, P.O. Box 80260, Jeddah 21589,
Saudi Arabia
e-mail: sherifrostom@yahoo.com
H. M. Faidallah
Faculty of Science, Department of Chemistry,
King Abdulaziz University, Jeddah 21589, Saudi Arabia
M. S. Al-Saadi
Faculty of Medicine, Division of Medicinal Chemistry,
King Abdulaziz University, Jeddah 21589, Saudi Arabia
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Med Chem Res (2011) 20:1260–1272
1261
(Perez-Rebolledo et al., 2005; Kamal et al., 2007), anti-
proliferative (Poreba et al., 2001; Kim et al., 2010), anti-
cancer (Segapelo et al., 2009; Abadi et al., 2009), CDK
kinase (Huang et al., 2007; Jacquemard et al., 2008) and
topoisomerase I, II inhibitory activities (Thapa et al.,
2010). Penclomedine (PEN1, 3,5-dichloro-4,6-dimethoxy-
2-(trichloromethyl)pyridine), is an antitumor agent which
was selected for clinical development by the NCI based on
its selective antitumor activity against some carcinomas
(Tiwari et al., 2002). Furthermore, particular interest
has been focussed on the anticancer activity of cyanopyr-
idine derivatives, for instance, some 2-cyanopyridylurea,
3-cyano-2,6-dihydropyridine, and dicyanopyridine deriva-
tives have been claimed for their antitumor properties in
treating hyperproliferative and angiogenesis disorders
(Cocco et al., 2005), whereas other substituted cyanopyri-
dines were reported to possess remarkable antitumor as
well as anti-HCV activities (El-Hawash et al., 2006).
During our ongoing studies aimed at the discovery of new
structure leads endowed with diverse chemotherapeutic
activities (Fahmy et al., 2002, 2003; Rostom et al., 2003a, b;
Al-Saadi et al., 2005a; Rostom, 2006; Faid-Allah et al., 2007;
Al-Saadi et al., 2008a, b; Rostom et al., 2009a, b), much
concern has been given to the antimicrobial and antitumor
potentials of some pyridines (Al-Saadi et al., 2005b; Faid
Allah et al., 2008; Rostom et al., 2009c), among which those
comprising the 3-cyano-4,6-disubstituted-2(1H)-pyridinone
scaffold (Al-Saadi et al., 2005b). Some of these compounds
were selected by the NCI to be evaluated for their antitumor
potentials, where they exhibited promising broad-spectrum
antitumor activity against several subpanel tumor cell lines.
The results obtained (reported herein for the first time)
prompted the design and synthesis of new analogs with fur-
ther structure modification of the above-mentioned scaffold
by introducing various pharmacophores and functionalities at
positin-1 that are believed to be responsible for the biological
significance of some relevant anticancer agents such as the
formyl, acetyl, nitroso, benzenesulfonyl, thioureido, and
alkyl groups. The substitution profile of the main pyridine
ring was designed so as to comprise some biologically active
counterparts such as the pyrrolyl, thienyl, and methoxylated
phenyl rings, together with other pharmacophoric groups that
would confer different electronic, lipophilic, and steric
environment, which would influence the targeted anticancer
activity. Moreover, it was considered worthwhile to utilize
the N-acetyl derivatives as precursors for the synthesis of the
fused-ring system triazolo[3,4-a]pyridine as an interesting
structural variation, hoping to improve the anticipated che-
motherapeutic activity. The in vitro antitumor activity of the
newly synthesized compounds has been evaluated according
to the protocol of the NCI (Grever et al., 1992; Boyd and
Paull, 1995; Monks et al., 1991).
Chemistry
The synthetic routes adopted for the preparation of the
intermediate and target compounds are described in
Schemes 1 and 2. In the first part, two synthetic strategies
were adopted to synthesize the target cyanopyridinones
4a–c according to a reported procedure (Al-Saadi et al.,
2005b). The first method involved the formation of the
intermediate 1,3-disubstituted-2-propen-1-ones 3a–c (chal-
cones) via Claisen–Schmidt condensation of the appropri-
ate aryl or hetaryl aldehydes 2a,b with the appropriate
ketones 1a–c using ethanolic potassium hydroxide. These
chalcones, in their turn, were allowed to react with ethyl
cyanoacetate and ammonium acetate to yield the target
3-cyano-4,6-disubstituted-2(1H)-pyridinones 4a–c. On the
other hand, the same compounds 4a–c could be directly
prepared via one-pot multicomponent reaction (MCR) of
the appropriate ketones 1a–c, the aldehydes 2a,b, an excess
of ammonium acetate and ethyl cyanoacetate in boiling
ethanol. Such type of reactions has received considerable
interest since it is easier to perform, gives higher yields and
less time consuming. Therefore, a comparison of the data
obtained from the above-mentioned synthetic methods
revealed that the one-pot reaction was better in terms of
yield percentage.
In their turn, the pyridinones 4a-c obtained from
Scheme 1 were utilized as key intermediates for the syn-
thesis of the target compounds in the second part (Scheme
2). In this respect, heating 4a–c with formic acid resulted in
the formation of the N-formyl pyridinones 5a–c. Whereas,
reacting the same starts with sodium nitrite in the presence
of cold acetic acid was used to synthesize the N-nitroso
derivatives 6a–c. Condensation of 4a–c with the appro-
priate aryl isothiocyanate in alkaline medium afforded the
corresponding N-arylthiocarbamoyl pyridinones 7a-f. Fur-
thermore, when compounds 4a–c were alkylated with
either ethyl iodide or benzyl chloride in the presence of
sodium hydroxide, the targeted N-alkyl pyridinones 8a–
f were formed, but in low yields. However, better yields
were obtained when the reaction was carried out in pyri-
dine as a basic solvent. At this stage, it was thought of
interest to study the effect of applying different conditions
that affect the alkylation of such type of pyridinones. In
this respect, compounds 4a–c were treated with the same
alkyl halides in the presence of ethanolic silver nitrate
according to a reported procedure (Hopkins et al., 1966) in
an attempt to obtain the O-alkyl derivatives 9, nevertheless,
such method failed to produce the targeted compounds.
Furthermore, adopting another reported procedures that
utilize sodium ethoxide as a basic catalyst instead of silver
nitrate (Kornblum et al., 1963a, b) were also insufficient to
afford the O-alkylated compounds 9. On the other hand,
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1262
Med Chem Res (2011) 20:1260–1272
Scheme 1 Reagents and
O
O
reaction conditions: i potassium
hydroxide, ethanol, r.t., 6-8 h, ii
ethyl cyanoacetate, ammonium
acetate, ethanol, reflux, 6–8 h,
iii (one-put) ethyl cyanoacetate,
ammonium acetate, ethanol,
reflux, 3–6 h
+
R1
H
R
2a,b
1a-c
R = a: 4-BrC6H4,
R1 = a: 1-methylpyrrol-2-yl,
b: 4-CH3OC6H4
b: 3,4-di-CH3OC6H3,
c: 2-thienyl
iii
i
R1
CN
ii
O
R
N
H
O
R
R1
4a-c
3a-c
3, 4: R = a: 4-BrC6H4, b: 3,4-di-3,4-di-CH3OC6H3, c: 2-thienyl;
R1 = a,b: 1-methylpyrrol-2-yl, c: 4-CH3OC6H4
reacting compounds 4a–c with benzenesulfonyl chloride in
the presence of pyridine resulted in the introduction of a
phenylsulfonyl moiety at position-1 to yield compounds
10a–c. Warming the starting compounds 4a–c with acetic
anhydride in the presence of anhydrous sodium acetate
afforded the N-acetyl derivatives 11a–c. In their turn, when
compounds 10a–c were reacted with hydrazine hydrate, the
targeted 1,2,4-triazolo[3,4-a]pyridines 12a–c were suc-
cessfully obtained.
cell lines. Only compounds which satisfy pre-determined
threshold inhibition criteria would progress to the 5-dose
screen. The threshold inhibition criteria for progression to
the 5-dose screen was designed to efficiently capture
compounds with anti-proliferative activity and is based on
careful analysis of historical Development Therapeutic
Program (DTP) screening data. The data are reported as a
mean graph of the percent growth of treated cells, and
presented as percentage growth inhibition (GI%) caused by
the test compounds (Table 1).
The obtained data revealed that, some of the tested
subpanel tumor cell lines exhibited some sensitivity pro-
files against most of the tested compounds. Among these,
the non-small cell lung cancer HOP-92 cell line exhibited a
variable degree of sensitivity toward 17 out of the tested
compounds, with particular sensitivity toward compounds
8b and 12b (GI values 44.7 and 48.0%, respectively).
Meanwhile, moderate activity toward the same cell line
was displayed by compounds 6c, 7b, and 12a (GI values
36.2, 39.6, and 30.0%, respectively). Concerning the Leu-
kemia subpanel, most of the tested compounds revealed
considerable growth inhibitory activities against most of
the tested cell lines, especially the CCRF-CEM cell line.
Particular high activities against this cell line were shown
by compounds 8a, 10a, 10c, and 12a with GI values of
62.5, 55.9, 56.2, and 66.0%, respectively. Whereas, com-
pounds 5b, 6c, 7b, 8b, 8c, and 12b proved to exert mod-
erate growth inhibition on the same cell line with values GI
In vitro antitumor screening
Primary in vitro one-dose assay
Out of the newly synthesized compounds, 24 derivatives
were selected for the evaluation of their antitumor activity
as per National Cancer Institute (NCI) in vitro protocol
(Grever et al., 1992; Boyd and Paull, 1995; Monks et al.,
1991).
Effective one-dose assay has been added to the NCI 60
Cell screen in order to increase compound throughput and
reduce data turnaround time to suppliers while maintaining
efficient identification of active compounds. All com-
pounds submitted to the NCI 60 Cell screen, are now tested
initially at a single high dose (10 lM) in the full NCI 60
cell panel including leukemia, non-small cell lung, colon,
CNS, melanoma, ovarian, renal, prostate, and breast cancer
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Med Chem Res (2011) 20:1260–1272
1263
Scheme 2 Reagents and
R1
N
R1
R1
N
reaction conditions: i formic
acid, reflux, 3 h, ii sodium
nitrite, acetic acid, 0°C, 2 h, iii
R2NCS, pyridine, reflux, 6–8 h,
iv R3X, pyridine, reflux, 3–4 h,
v R3X, ethanol, silver nitrate or
sodium ethoxide, reflux, 3–10 h,
vi benzenesulfonyl chloride,
pyridine, reflux, 4–6 h, vii
acetic anhydride, anhyd. sodium
acetate, reflux, 4 h, viii
CN
O
CN
O
CN
O
R
H
R
N
R
NO
N
S
H
O
R2
6a-c
7a-f
5a-c
ii
i
iii
hydrazine hydrate 98%, ethanol,
reflux, 6–8 h
R1
R1
R1
CN
O
CN
CN
O
R3
R
N
R
N
9
O
v
R
N
H
iv
R3
8a-f
4a-c
vii
vi
R1
R1
N
R1
CN
CN
O
CN
viii
R
N
O
R
R
N
N
SO2
N
O
11a-c
12a-c
10a-c
5, 6, 10, 11, 12: R = a: 4-BrC6H4, b: 3,4-di-CH3OC6H3, c: 2-thienyl;
R1 = a,b: 1-methylpyrrol-2-yl, c: 4-CH3OC6H4
7: R = a: 4-BrC6H4, b: 3,4-di-CH3OC6H3, c: 2-thienyl;
R1 = a,b: 1-methylpyrrol-2-yl, c: 4-CH3OC6H4 ;
R2 = a, c, e: C6H5, b, d, f: 4-FC6H4
8: R = a: 4-BrC6H4, b: 3,4-di-CH3OC6H3, c: 2-thienyl;
R1 = a,b: 1-methylpyrrol-2-yl, c: 4-CH3OC6H4 ;
R3 = a, c, e: C2H5, b, d, f: CH2C6H5
of 47.1, 42.0, 48.3, 39.5, 43.7, and 39.2%, respectively.
Furthermore, remarkable sensitivity profile was shown by
the Leukemia K-562 cell line toward compounds 5a, 6c,
7b, 8b, 8c, 8f, and 12b with GI values of 54.8, 65.8, 60.0,
45.4, 63.5, 50.4, and 41.5%, respectively. In relation to the
Leukemia HL-60(TB), the growth of this cell line was
potentially inhibited by the presence of compound 7b (GI
value 82.2%), whereas, compounds 5b, 10a, and 10c
showed appreciable growth inhibition on the same cell line
with values of 57.1, 59.7, and 55.0%, respectively. Addi-
tionally, Leukemia RPMI-8226 cell line showed mild
sensitivity toward compounds 8a, 8b, 12a, and 12b (GI%
range 32.1–43.2), meanwhile, compounds 7b and 8d
proved to exert a recognizable inhibitory activity against
the same cell line (GI values 59.2 and 64.1%). It is worth-
mentioning that, both of the prostate cancer cell lines were
resistant to most of the tested compounds, except for
compounds 8a, 8b, 12a, and 12b, which showed weak
activity against the PC-3 cell line, with GI values of 28.0,
32.5, 24.0, and 23.8%, respectively.
Further interpretation of the results revealed that, the
4-fluorophenyl thiocarbamoyl 2(1H)-pyridinone analog 7b
proved to be the most active member in this primary bio-
assay, with a broad spectrum of growth inhibitory activity
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Med Chem Res (2011) 20:1260–1272
Table 1 In vitro percentage growth inhibition (GI %) caused by the selected compounds against some tumor cell lines at the single-dose assay
Cpd no.
Panel
Subpanel tumor cell lines (% growth inhibitory activity)
5a
Non-small cell lung cancer
Ovarian cancer
HOP-92 (24.2)
OVCAR-5 (26.9)
Leukemia
K-562 (54.8)
Renal Cancer
UO-31 (29.7)
5b
6a
Leukemia
CCRF-CEM (47.1), HL-60 (TB) (57.1), K-562 (21.4), MOLT-4 (28.5)
Non-small cell lung cancer
Leukemia
HOP-92 (28.2), BT-549 (32.8)
SR (37.5)
Renal Cancer
A498 (25.7)
6b
6c
7b
Non-small cell lung cancer
Leukemia
HOP-92 (26.8)
K-562 (26.6)
Non-small cell lung cancer
Leukemia
HOP-92 (36.2)
CCRF-CEM (42.0), K-562 (65.8)
Non-small cell lung cancer
A549/ATCC (47.8), EKVX (29.7), HOP-62 (34.5), HOP-92 (39.6),
NCI-H460 (31.6),
Colon cancer
COLO 205 (45.6), HCC–2998 (27.6)
MDA-MB-435 (35.1)
Breast cancer
Leukemia
CCRF-CEM (48.3), HL-60 (TB) (82.3), K-562 (60.0), RPMI-8226 (59.2)
786-0 (28.8), A498 (27.6), CAKI-1 (30.3),
LOX IMVI (23.0), M14 (29.1), SK-MEL-5 (33.5)
SF-295 (40.2), SNB-75 (42.7), U251 (26.3)
K-562 (26.9), SR (27.8)
Renal cancer
Melanoma
CNS cancer
7d
8a
Leukemia
Renal cancer
CAKI-1 (31.1)
Non-small cell lung cancer
Breast cancer
HOP-92 (28.3)
MDA-MB-468 (30.0)
Leukemia
CCRF-CEM (62.5), RPMI-8226 (35.0)
PC-3 (28.0)
Prostate cancer
Non-small cell lung cancer
Leukemia
8b
8c
HOP-92 (44.7)
CCRF-CEM (39.5), K-562 (45.4), PRMI-8226 (38.2)
PC-3 (32.5)
Prostate cancer
Non-small cell lung cancer
Leukemia
HOP-92 (29.0)
CCRF-CEM (43.7), K-562 (63.5)
A498 (44.0)
Renal cancer
8d
8f
Leukemia
RPMI-8226 (64.1)
Non-small cell lung cancer
Leukemia
HOP-92 (26.8), NCI-H23 (21.0), NCI/ADR-
K-562 (50.4)
Renal cancer
UO-31 (23.5)
10a
10b
Non-small cell lung cancer
Leukemia
HOP-92 (26.0), NCI-H23 (22.2)
CCRF-CEM (55.9), HL-60 (TB) (59.7), K-562 (22.5), MOLT-4 (26.6)
HOP-92 (25.8),
Non-small cell lung cancer
Breast cancer
BT-549 (21.0)
Leukemia
SR (31.4)
10c
Non-small cell lung cancer
Leukemia
HOP-92 (21.3), NCI-H23 (20.0)
CCRF-CEM (56.2), HL-60 (TB) (55.0), K-562 (27.7), MOLT-4 (28.1),
RPMI-8226 (22.0)
11a
11b
11c
Non-small cell lung cancer
Leukemia
HOP-92 (24.6)
K-562 (25.3)
HOP-92 (29.6)
SR (30.5)
Non-small cell lung cancer
Leukemia
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Med Chem Res (2011) 20:1260–1272
1265
Table 1 continued
Cpd no.
Panel
Subpanel tumor cell lines (% growth inhibitory activity)
12a
Non-small cell lung cancer
Leukemia
HOP-92 (30.0)
CCRF-CEM (66.0), RPMI-8226 (43.2)
PC-3 (24.0)
Prostate Cancer
12b
Non-small cell lung cancer
Breast cancer
HOP-92 (48.0)
T-47D (34.3), MCF7 (29.0)
CCRF-CEM (39.2), K-562 (41.5), RPMI-8226 (32.1)
PC-3 (23.8)
Leukemia
Prostate cancer
CNS Cancer
SNB-75 (25.8)
12c
Non-small cell lung cancer
HOP-92 (23.5)
The data obtained from NCI’s in vitro disease-oriented human tumor cell screen at 10 lM conc
against seven of the nine tested subpanel tumor cell lines,
and particular effectiveness against the Leukemia subpanel
tumor cell lines CCRF-CEM, HL-60 (TB), K-562, and
RPMI-8226 (GI% 48.3, 82.3, 60.0, and 59.2, respectively).
In addition, the bicyclic [1,2,4]triazolo[3,4-a]pyridine
derivative 12b was also able to exhibit a noticeable spec-
trum of antitumor activity against five different subpanels,
with special moderate growth inhibitory activity on the
Leukemia tumor cell lines CCRF-CEM, K-562, and RPMI-
8226 (GI% values 39.2, 41.5, and 32.1, respectively).
Consequently, compounds 7b and 12b passed this primary
anticancer assay and were carried over to the 5-dose screen
against a panel of about 60 different tumor cell lines.
and default GI50, TGI, or LC50 values of all cell lines in the
subpanel or the full panel, respectively. The NCI antitumor
drug discovery was designed to distinguish between broad-
spectrum antitumor compounds and tumor or subpanel-
selective agents.
In this part of the present study, the active five com-
pounds including the previously prepared 4a and 4b (Al-
Saadi et al., 2005b), together with the new analogs; 4c, 7b,
and 12b, exhibited variable degree of antitumor activities
against some of the tested subpanel tumor cell lines (GI50,
TGI, and LC50 values \100 lM). These compounds
showed particular sensitivity toward some individual cell
lines, as well as a broad spectrum (MG-MID) of antitumor
activity (Table 2).
In vitro full panel (five-dose) 60-cell line assay for
compounds 4a–c, 7b, and 12b
With regard to the sensitivity against some individual
cell lines, compound 4a revealed mild to moderate growth
inhibitory activity against 14 tumor cell lines belonging to
7 different subpanels, with special influence on the non-
small cell lung Hop-92 and CNS SNB-75 cell lines (GI50
27.5 and 25.7 lM, respectively). Furthermore, compound
4b was also able to inhibit the growth of 14 different cell
lines, with a remarkable activity against the leukemia
CCRF-CEM and SR cell lines (GI50 5.01 and 0.48 lM,
respectively) and a distinctive sensitivity to the non-small
cell lung HOP-92 cell line at both the GI50 (0.05 lM) and
the TGI (9.77 lM) levels. Moreover, it revealed moderate
antitumor activity against the leukemia RPMI-8226, non-
small cell lung EKVX, CNS SNB-75 and breast T-47D cell
lines with GI50 values of 22.9, 30.9, 23.9, and 34.7 lM,
respectively. Meanwhile, compound 4c exhibited weak
antitumor profile against 6 cell lines, nevertheless, with
considerable equipotent activity against leukemia CCRF-
CEM and RPMI-8226 cell lines (GI50 23.4 and 22.4 lM,
respectively). Shifting to the analog 7b, it showed obser-
vable antitumor spectrum against 10 different cell lines,
with a distinctive growth inhibitory and cytostatic poten-
tials against the non-small cell lung HOP-92 cell line (GI50
0.01 and TGI 0.03 lM, respectively), and a reliable
Five compounds namely, 4a–c and 7b and 12b, were
selected to be evaluated for their antitumor activities
according to the in vitro full panel (five-dose) 60-cell line
assay. (Grever et al., 1992; Boyd and Paull, 1995; Monks
et al., 1991).
About 60 cell lines of nine tumor subpanels, including
leukemia, non-small cell lung, colon, CNS, melanoma,
ovarian, renal, prostate, and breast cancer cell lines, were
incubated with five concentrations (0.01–100 lM) for each
compound and were used to create log concentration-%
growth inhibition curves. Three response parameters (GI50,
TGI, and LC50) were calculated for each cell line. The GI50
value (growth inhibitory activity) corresponds to the con-
centration of the compounds causing 50% decrease in net
cell growth, the TGI value (cytostatic activity) is the con-
centration 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).
Subpanel and full panel mean-graph midpoint values (MG-
MID) for certain agents are the average of individual real
123

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Med Chem Res (2011) 20:1260–1272
Table 2 Growth inhibitory concentration (GI50, lM) of some selected in vitro tumor cell lines of compounds 4a–c, 7b, and 12b
Cell lines
4a
4b
4c
7b
12b
Leukemia
a
CCRF-CEM
HL-60(TB)
RPMI-8226
SR
47.3
–
5.01
–
23.4
45.7
22.4
60.2
–
–
14.5
–
–
57.5
–
22.9
0.48
19.0 (45.7)b
–
–
Non-small cell lung cancer
EKVX
34.7
–
30.9
–
–
–
–
37.1
37.1
HOP-62
–
–
–
HOP-92
27.5
34.7
0.05 (9.77)
30.9
0.01 (0.03)
37.1
0.01 (0.03)
37.1
EKVX
Colon cancer
HCC-2998
CNS cancer
SF-268
–
89.1
–
–
–
–
–
–
20.4
–
–
SF-539
89.1
25.7
67.6
23.9
–
–
SNB-75
39.8
38.0
44.7
Melanoma
UACC-62
48.9
66.1
–
72.4
95.5
Ovarian cancer
IGROV1
77.6
85.1
–
91.2
–
–
22.9
–
–
–
–
OVCAR-3
OVCAR-4
Renal cancer
A498
–
–
69.2
–
54.9
69.2
56.2
85.1
–
–
17.8
13.8 (27.5) (54.9)c
25.7
–
UO-31
Breast cancer
MDA-MB-231/ATCC
BT-549
83.2
85.1
–
–
–
–
–
–
–
–
–
T-47D
34.7
67.6
95.5
–
–
–
–
GI50 (MG-MID)d
TGI (MG-MID)e
LC50 (MG-MID)f
77.6
85.1
–
91.2
–
83.2
95.5
–
89.1
–
–
–
Data obtained from NCI’s in vitro disease-oriented human tumor cell screen
a
Values [100 lM
b
Total growth inhibitory concentration value (TGI, lM)
c
Lethal concentration 50 value (LC50, lM)
d
GI50 (lM) full panel mean-graph mid point (MG-MID) = the average sensitivity of all cell lines toward the test agent
TGI (lM) full panel mean-graph mid point (MG-MID) = the average sensitivity of all cell lines toward the test agent
LC50 (lM) full panel mean-graph mid point (MG-MID) = the average sensitivity of all cell lines toward the test agent
e
f
activity against the leukemia HL-60(TB) and renal A498
HOP-92 and leukemia RPMI-8226 cell lines at both the
GI50 (0.01 and 19.0 lM) and the TGI (0.03 and 45.7 lM)
levels.
cell lines (GI50 14.5 and 17.8 lM, respectively). Mean-
while, the same compound displayed significant growth
inhibitory, cytostatic, and cytotoxic activities on the renal
UO-31 cell line with GI50, TGI, and LC50 values of 13.8,
27.5, and 54.9 lM, respectively. Finally, the bicyclic
derivative 12b was able to affect the growth of 7 cell lines,
with particular activity against the non-small cell lung
Concerning the broad-spectrum antitumor activity, the
results revealed that the five active compounds; 4a, 4b, 4c,
7b, and 12b, showed effective growth inhibition GI50 (MG-
MID) values of 77.6, 67.6, 91.2, 83.2, and 89.1 lM,
respectively. Moreover, three compounds namely; 4a, 4b,
123

Med Chem Res (2011) 20:1260–1272
1267
3-(4-Methoxyphenyl)-1-(2-thienyl)-2-propen-1-one 3c
and 7b were able to display a cytostatic activity with TGI
(MG-MID) values of 85.1, 95.5, and 95.5 lM, respectively
(Table 2). However, all the tested compounds were
deprived of any cytotoxic efficacy (LC50 (MG-MID) values
[100 lM).
A solution of the 4-methoxybenzaldehyde 2c (1.36 g,
10 mmol) in ethanol (20 ml) was added to a stirred solu-
tion of 2-acetylthiophene 1c (1.26 g, 10 mmol) in ethanolic
potassium hydroxide (20%) (20 ml), and stirring was
maintained at room temperature for 6 h. The reaction
mixture was then poured onto water (200 ml) and set aside
for an overnight. The precipitated solid product was col-
lected by filtration, washed with water, dried, and recrys-
tallized from ethanol. Yield: 92%; m.p. 80–82°C; IR
(cm-1): 1665 (C=O). 1H-NMR (d-ppm): 3.67 (s, 3H,
OCH3), 6.58–7.41 (m, 6H, 2 olefinic H, and 4 Ar–H),
7.58–7.72 (m, 3H, 3, and thiophen-H). Analysis for
C14H12O2S (244.31): C: 68.83; H: 4.95. Found: C: 68.96;
H: 4.79.
Further interpretation of the obtained results indicated
that, better antitumor activity was confined to those
derivatives comprising either the 4-bromophenyl or
3,4-dimethoxyphenyl moieties, together with a 1-methyl-
1H-pyrrol-2-yl counterpart at positions 6 and 4, respec-
tively, at the main 3-cyano-2(1H)-pyridinone scaffold. In
this view, the 3-cyano-4-(1-methyl-1H-pyrrol-2-yl)-6-(4-
bromophenyl or 3,4-dimethoxyphenyl)-2(1H)-pyridinones
4a and 4b, could be considered as the most active members
identified in this investigation as evidenced from their
relative higher growth inhibitory (GI50 (MG-MID) 77.6
and 67.6 lM, respectively) and cytostatic (TGI (MG-MID)
85.1 and 95.5 lM, respectively) potentials, when compared
with the substituted thiocarbamoyl analog 7b and the
bicyclic [1,2,4]triazolo[3,4-a]pyridine derivative 12b. In
addition, the active compounds revealed special effective-
ness against the leukemia subpanel, particularly the CCRF-
CEM and RPMI-8226 cell lines, beside their pronounced
activity toward the non-small cell lung cancer HOP-92 cell
line (Table 2).
3-Cyano-4-(4-methoxyphenyl)-6-(2-thienyl)-2(1H)-
pyridinone 4c
Method A
A mixture of the chalcone 3c (2.44 g, 10 mmol), ethyl
cyanoacetate (1.1 g, 10 mmol), and ammonium acetate
(6.2 g, 80 mmol) in absolute ethanol (30 ml) was heated
under reflux for 8 h. After being cooled to room tempera-
ture, the solid product formed was filtered, washed with
water, dried, and recrystallized from the DMF containing
few drops of water (Yield: 36%)
All these favorable features make such type of pyridine
derivatives the appropriate candidates for further derivati-
zation in order to explore the scope and limitations of their
potential, hoping to find more selective and active anti-
cancer and/or antileukemic agent(s).
Method B
A one-pot mixture of 2-acetylthiophene 1c (1.26 g,
10 mmol), 4-methoxybenzaldehyde 2c (1.36 g, 10 mmol),
ethyl cyanoacetate (1.1 g, 10 mmol), and ammonium ace-
tate (6.2 g, 80 mmol) in absolute ethanol (50 ml) was
refluxed for 6 h. The reaction mixture was allowed to cool,
and the formed precipitate was filtered, washed with water,
dried, and recrystallized (Yield: 51%).
M.p.: 244–246°C; IR (cm-1): 3400–3250 (NH), 2210
(CN), 1675 (C=O). 1H-NMR (d-ppm): 3.82 (s, 3H, OCH3),
6.24 (s, 1H, pyridine C5-H), 6.81–7.64 (m, 7H, 3 thiophen-
H, and 4 Ar–H), 8.21 (s, 1H, NH). Analysis for
C17H12N2O2S (308.35): C: 66.22; H: 3.92; N: 9.08. Found:
C: 65.96; H: 4.13; N: 9.27.
Experimental
Melting points were determined on a Gallenkamp melting
point apparatus and are uncorrected. The infrared (IR)
spectra were recorded on Shimadzu FT-IR 8400S infrared
spectrophotometer using the KBr pellet technique. 1H-
NMR spectra were recorded on a Bruker DPX-400 FT
NMR spectrometer using tetramethylsilane as the internal
standard and DMSO-d6 as a solvent (Chemical shifts in d,
ppm). Splitting patterns were designated as follows: s:
singlet; d: doublet; m: multiplet; q: quartet. Elemental
analyses were performed on a 2400 Perkin Elmer Series 2
analyzer and the found values were within 0.4% of the
theoretical values. Follow up of the reactions and checking
the homogeneity of the compounds were made by TLC on
silica gel-protected aluminum sheets (Type 60 F254,
Merck) and the spots were detected by exposure to
UV-lamp at k 254. The synthesis, physicochemical, and
analytical data of compounds 3a,b and 4a,b are reported in
reference Al-Saadi et al. (2005b).
3-Cyano-1-formyl-4,6-disubstituted-2(1H)-pyridinones
5a–c
A solution of the appropriate pyridinone 4a–c (3 mmol) in
formic acid (5 ml) was heated under reflux for 3 h. The
reaction mixture was poured on crushed ice and the
123

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Med Chem Res (2011) 20:1260–1272
3-Cyano-1-nitroso-4,6-disubstituted-2(1H)-pyridinones
6a–c
separated solid product was filtered, washed with water,
dried, and recrystallized. Physicochemical and analytical
data are recorded in Table 3. IR (cm-1): 2220–2210 (CN),
1678–1670 (C=O pyridone), 1663–1657 (C=O aldehyde).
1H-NMR (d-ppm) for 5b (R = 3,4-diOCH3-C6H3, R1 = 1-
methylpyrrol-2-yl): 3.46 (s, 3H, CH3), 3.75 (s, 3H, OCH3),
3.81 (s, 3H, OCH3), 6.74–7.66 (m, 7H, 3 Ar–H, 3 pyrrole-
H, and pyridine C5-H), 8.37 (s, 1H, aldehyde-H).
To an ice-cooled stirred solution of the appropriate start
4a–c (3 mmol) in acetic acid (10 ml), was added dropwise
a solution of sodium nitrite (0.28 g, 4 mmol) in water
(5 ml) over a period of 2 h. Stirring was maintained for
further 2 h, then the reaction mixture was left aside at room
Table 3 Physicochemical and analytical data of compounds 5–12
Cpd. no.
R
R1
R2 or R3 M.p. °C
Yield % Mol. formula
(mol. weight)
Analysis
(Solvent)a
% Calcd. Found
5a
4-BrC6H4
1-methyl-pyrrol-2-yl
–
–
–
–
–
–
111–113 (E)
109–110 (E)
60
78
C18H12BrN3O2 (382.21)
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
56.56
3.16
56.19
2.83
10.99
66.11
4.72
11.24
65.87
4.97
5b
5c
6a
6b
6c
7a
7b
7c
7d
7e
7f
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl
C20H17N3O4 (363.37)
C18H12N2O3S (336.36)
C17H11BrN4O2 (383.21)
C19H16N4O4 (364.35)
C17H11N3O3S (337.35)
11.56
64.27
3.6
11.31
64.39
3.41
2-thienyl
4-BrC6H4
4-OCH3-C6H4
221–227 (D/W) 75
8.33
8.12
1-methyl-pyrrol-2-yl
108–110 (E)
112–114 (E)
87
39
53.28
2.89
53.13
3.07
14.62
62.63
4.43
14.46
62.37
4.58
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl
15.38
60.52
3.29
15.04
60.16
3.44
2-thienyl
4-BrC6H4
4-BrC6H4
4-OCH3-C6H4
231–232 (D/W) 79
12.46
58.9
12.72
59.22
3.41
1-methyl-pyrrol-2-yl C6H5
155–157 (E)
74
70
C24H17BrN4O S
(489.39)
3.5
11.45
56.81
3.18
11.63
57.26
3.4
1-methyl-pyrrol-2-yl 4-F-C6H4 103–105 (E)
C24H16BrFN4OS
(507.38)
11.04
66.37
4.71
10.88
66.41
4.54
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl C6H5
102–104 (E/W) 60
C26H22N4O3S (470.54)
C26H21FN4O3S (488.53)
C24H17N3O2S2 (443.54)
11.91
63.92
4.33
12.06
64.05
4.17
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl 4-F-C6H4 106–108 (E/W) 55
11.47
64.99
3.86
11.59
65.28
3.61
2-thienyl
2-thienyl
4-OCH3-C6H4
4-OCH3-C6H4
C6H5
218–220 (DMF/ 72
W)
9.47
9.76
4-F-C6H4 226–227 (DMF/ 65
W)
C24H16FN3O2S2
(461.53)
62.46
3.49
62.25
3.67
9.1
9.23
123

Med Chem Res (2011) 20:1260–1272
1269
Table 3 continued
Cpd. no.
R
R1
R2 or R3 M.p. °C
Yield % Mol. formula
(mol. weight)
Analysis
% Calcd. Found
(Solvent)a
8a
4-BrC6H4
1-methyl-pyrrol-2-yl C2H5
1-methyl-pyrrol-2-yl CH2–
101–103 (B/PE) 79
C19H16BrN3O (382.25)
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
C
H
N
59.7
59.54
4.46
4.22
10.99
64.88
4.08
11.07
64.51
3.96
8b
4-BrC6H4
108-110 (E/B)
107–109 (E)
59
67
45
C24H18BrN3O (444.32)
C21H21N3O3 (363.41)
C26H23N3O3 (425.48)
C19H16N2O2S (336.41)
C24H18N2O2S (398.48)
C6H5
9.46
9.73
8c
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl C2H5
69.41
5.82
69.3
6.02
11.56
73.39
5.45
11.37
73.56
5.13
8d
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl CH2–
99–101 (B/PE)
C6H5
9.88
10.09
67.98
4.43
8e
2-thienyl
2-thienyl
4-BrC6H4
4-OCH3-C6H4
C2H5
233–235 (A/W) 79
229–231 (A/W) 68
67.84
4.79
8.33
8.26
8f
4-OCH3-C6H4
CH2–
C6H5
72.34
4.55
72.06
4.71
7.03
6.89
10a
10b
10c
11a
11b
11c
12a
12b
12c
a
1-methyl-pyrrol-2-yl
–
–
–
–
–
–
–
–
–
101–103 (E)
97–99 (E/B)
166–168 (E)
145–147 (E)
128–130 (E)
67
53
66
72
68
61
34
20
C23H16BrN3O3S
(494.36)
55.88
3.26
56.04
3.13
8.5
8.27
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl
C25H21N3O5S (475.52)
C23H16N2O4S2 (448.51)
C19H14BrN3O2 (396.24)
C21H19N3O4 (377.39)
C19H14N2O3S (350.39)
C19H14BrN5 (392.25)
C21H19N5O2 (373.41)
C19H14N4OS (346.41)
63.15
4.45
62.86
4.63
8.84
8.55
2-thienyl
4-BrC6H4
4-OCH3-C6H4
61.59
3.6
61.4
3.72
6.25
6.01
1-methyl-pyrrol-2-yl
57.59
3.56
57.41
3.63
10.6
10.27
67.01
4.92
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl
66.83
5.07
11.13
65.13
4.03
11.27
64.88
3.81
2-thienyl
4-BrC6H4
4-OCH3-C6H4
256–258
(DMF/W)
7.99
8.14
1-methyl-pyrrol-2-yl
123–125 (E)
117–119 (E)
58.18
3.6
58.29
3.43
17.85
67.55
5.13
17.61
67.31
5.34
3,4-di-CH3O-C6H3 1-methyl-pyrrol-2-yl
18.76
65.88
4.07
18.32
65.97
3.82
2-thienyl
4-OCH3-C6H4
224–226 (D/W) 27
16.17
16.24
Crystallization solvents: E ethanol, B benzene, W water. DMF N,N-dimethylformamide, D 1,4-dioxan, PE petroleum ether (60/80)
123

1270
Med Chem Res (2011) 20:1260–1272
temperature for overnight. The formed solid product was
filtered, washed with water, dried, and recrystallized.
Physicochemical and analytical data are recorded in
Table 3. IR (cm-1): 2223–2217 (CN), 1675–1667 (C=O
pyridone). 1H-NMR (d-ppm) for 6c (R = 2-thienyl,
R1 = 4-OCH3-C6H4): 3.71 (s, 3H, OCH3), 6.71–7.54 (m,
8H, 4 Ar–H, 3 thiophen-H, and pyridine C5-H).
6.65–7.72 (m, 8H, 4 Ar–H, 3 thiophen-H, and pyridine
C5-H).
3-Cyano-1-phenylsulfonyl-4,6-disubstituted-2(1H)-
pyridinones 10a–c
A mixture of the appropriate start 4a–c (3 mmol) and
benzenesulfonyl chloride (3 mmol) in pyridine (10 ml) was
heated under reflux for 4–6 h. After cooling to room tem-
perature, the reaction mixture was poured on crushed ice
and the separated solid product was filtered, washed with
water, dried, and recrystallized. Physicochemical and
analytical data are recorded in Table 3. IR (cm-1):
2230–2221 (CN), 1670–1665 (C=O pyridone), 1388–1370
and 1197–1175 (SO2). 1H-NMR (d-ppm) for 10b
(R = 3,4-diOCH3-C6H3, R1 = 1-methylpyrrol-2-yl): 3.42
(s, 3H, CH3), 3.78 (s, 3H, OCH3), 3.85 (s, 3H, OCH3),
6.69–7.95 (m, 12H, 8 Ar–H, 3 pyrrole-H, and pyridine C5-
H). For 10c: (R = 2-thienyl, R1 = 4-OCH3-C6H4): 3.75 (s,
3H, OCH3), 6.64 (s, 1H, pyridine C5-H), 6.82-7.88 (m,
12H, 9 Ar–H, and 3 thiophen-H).
3-Cyano-1-(substituted thiocarbamoyl)-4,6-
disubstituted-2(1H)-pyridinones 7a–f
A mixture of the appropriate starting compound 4a–
c (3 mmol) and the appropriate isothiocyanate (4 mmol) in
pyridine (10 ml) was heated under reflux for 6–8 h. After
being cooled to room temperature, the reaction mixture
was poured on ice cold water and the separated solid
product was filtered, washed with water, dried, and re-
crystallized. Physicochemical and analytical data are
recorded in Table 3. IR (cm-1): 2230–2215 (CN),
1
1678–1665 (C=O pyridone), 1232–1216 (C=S). H-NMR
(d-ppm) for 7a (R = 4-Br-C6H4, R1 = 1-methylpyrrol-2-
yl, R2 = C6H5): 3.49 (s, 3H, CH3), 5.87–6.24 (m, 4H, 3
pyrrole-H and pyridine C5-H), 6.68–7.27 (m, 9H, 9 Ar–H),
8.51 (s, 1H, NH). For 7c (R = 3,4-diOCH3-C6H3, R1 =
1-methylpyrrol-2-yl, R2 = C6H5): 3.45 (s, 3H, CH3), 3.80
(s, 3H, OCH3), 3.87 (s, 3H, OCH3), 6.41 (s, 1H, pyridine
C5-H), 6.73–7.84 (m, 11H, 8 Ar–H, 3 pyrrole-H), 8.47 (s,
1H, NH). For 7f (R = 2-thienyl, R1 = 4-OCH3-C6H4,
R2 = 4-F-C6H4): 3.83 (s, 3H, OCH3), 6.47 (s, 1H, pyridine
C5-H), 6.85–7.61 (m, 11H, 8 Ar–H, 3 thiophen-H), 8.55 (s,
1H, NH).
1-Acetyl-3-cyano-4,6-disubstituted-2(1H)-pyridinones
11a–c
To a solution of the appropriate 4a–c (3 mmol) in acetic
anhydride (10 ml), was added anhydrous sodium acetate
(0.37 g, 4.5 mmol). The reaction mixture was heated under
reflux for 4 h, allowed to cool, then poured on crushed ice
with vigorous stirring. The formed solid product was filtered,
thoroughly washed with water, dried, and recrystallized.
Physicochemical and analytical data are recorded in Table 3.
IR (cm-1): 2226-2215 (CN), 1725–1718 (C=O acetyl),
1678–1672 (C=O pyridone). 1H-NMR (d-ppm) for 11b
(R = 3,4-diOCH3-C6H3, R1 = 1-methylpyrrol-2-yl): 2.48
(s, 3H, CH3CO), 3.51 (s, 3H, N-CH3), 3.77 (s, 6H, 2 OCH3),
6.74–7.28 (m, 7H, 3 Ar–H, 3 pyrrole-H and pyridine C5-H).
For 11c: (R = 2-thienyl, R1 = 4-OCH3-C6H4): 2.51 (s, 3H,
CH3CO), 3.46 (s, 3H, N-CH3), 3.85 (s, 3H, OCH3), 6.69–7.68
(m, 8H, 4 Ar–H, 3 thiophen-H, and pyridine C5-H).
3-Cyano-1-(benzyl or ethyl)-4,6-disubstituted-2(1H)-
pyridinones 8a–f
To a solution of the appropriate pyridone 4a–c (3 mmol) in
pyridine (10 ml), was added the appropriate alkyl halide
(3 mmol) and the mixture was heated under reflux for 3–4 h.
The reaction mixture was allowed to attain room tempera-
ture, poured on ice cold water and the separated solid product
was filtered, washed with water, dried, and recrystallized.
Physicochemical and analytical data are recorded in Table 3.
IR (cm-1): 2222–2216 (CN), 1675–1668 (C=O pyridone).
1H-NMR (d-ppm) for 8a (R = 4-Br-C6H4, R1 = 1-methyl-
pyrrol-2-yl, R3 = CH2CH3): 1.49 (t, J = 4 Hz, 2H, CH3),
2.94 (q, J = 4 Hz, 2H, CH2), 3.44 (s, 3H, CH3), 6.59 (s, 1H,
pyridine C5-H), 6.88–7.94 (m, 7H, 4 Ar–H, and 3 pyrrole-H).
For 8d (R = 3,4-diOCH3-C6H3, R1 = 1-methylpyrrol-2-yl,
R3 = CH2-C6H5): 3.39 (s, 3H, CH3), 3.71 (s, 6H, 2 OCH3),
4.46 (s, 2H, CH2), 6.51 (s, 1H, pyridine C5-H), 6.92–7.88 (m,
11H, 8 Ar–H, and 3 pyrrole-H). For 8e (R = 2-thienyl,
R1 = 4-OCH3-C6H4, R3 = CH2CH3): 1.45 (t, J = 4 Hz,
2H, CH3), 2.87 (q, J = 4 Hz, 2H, CH2), 3.76 (s, 3H, OCH3),
8-Cyano-5,7-disubstituted-[1,2,4]-triazolo[3,4-
a]pyridines 12a–c
A mixture of the appropriate 1-acetylpyridinone 11a–
c (3 mmol) and hydrazine hydrate (0.3 g, 5 mmol) in
ethanol (15 ml) was heated under reflux for 6–8 h. The
reaction mixture was allowed to attain room temperature,
poured on crushed ice and the precipitated solid product
was filtered, washed with water, dried, and recrystallized.
Physicochemical and analytical data were recorded in
1
Table 3. IR (cm-1): 2220–2215 (CN). H-NMR (d-ppm)
for 12a (R = 4-Br-C6H4, R1 = 1-methyl-pyrrol-2-yl): 2.61
123

Med Chem Res (2011) 20:1260–1272
1271
Riyadh, KSA, for the financial support of this research work (Project
No. 106-26). Extendable thanks are conveyed to the staff members of
the National Cancer Institute (NCI) in vitro disease-oriented human
cells screening panel assay, Bethesda, Maryland, U.S.A, for carrying
out the in vitro anticancer screening.
(s, 3H, triazole CH3), 3.46 (s, 3H, N-CH3), 6.69–7.44 (m,
8H, 4 Ar–H, 3 pyrrole-H, and pyridine C5-H). For 12b
(R = 3,4-diOCH3-C6H3, R1 = 1-methylpyrrol-2-yl): 2.55
(s, 3H, triazole CH3), 3.49 (s, 3H, N-CH3), 3.74 (s, 6H, 2
OCH3), 6.81–7.52 (m, 7H, 3 Ar–H, 3 pyrrole-H, and pyr-
idine C5-H).
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