Synthesis and anticancer effects of pongamol derivatives on mitogen signaling and cell cycle kinases

Article abstract of DOI:10.1007/s00044-011-9563-y

A series of oxazole and pyrazole derivatives of pongamol (1) were designed and synthesized to examine their anti-cancer activity. The cytotoxicity of these compounds was examined in three different human tumor cell lines, IMR-32, HeLa and Jurkat. Although

Full text of DOI:10.1007/s00044-011-9563-y

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:634–641
DOI 10.1007/s00044-011-9563-y
ORIGINAL RESEARCH
Synthesis and anticancer effects of pongamol derivatives
on mitogen signaling and cell cycle kinases
•
R. Ranga Rao Vishal Chaturvedi K. Suresh Babu
•
•
•
P. Prabhakar Reddy V. Rama Subba Rao
•
•
P. Sreekanth A. S. Sreedhar J. Madhusudana Rao
•
Received: 28 October 2010 / Accepted: 12 January 2011 / Published online: 30 January 2011
Ó Springer Science+Business Media, LLC 2011
Abstract A series of oxazole and pyrazole derivatives of
pongamol (1) were designed and synthesized to examine
their anti-cancer activity. The cytotoxicity of these com-
pounds was examined in three different human tumor cell
lines, IMR-32, HeLa and Jurkat. Although all compounds
tested were quite effective than the pongamol against all
the three different types of cancer cell lines examined, the
compounds (2), (5), and (6) were found to be the most
active compounds of this series.
new anticancer agents, preferably with novel mechanisms
of action. To identify new chemical entities for a more
effective treatment of cancer, drug designers can follow
many strategies, but the crucial decision is always the
selection of a suitable starting point from the vast chemical
space (Lloyd et al., 2006).
In this respect, natural products evolved as privileged
structures (Koehn and Carter, 2005) and biologically pre-
validated leads, in other words, as molecules that have
probably evolved evolutionarily to exert highly specialized
functions. About 74% of anticancer compounds are form
both natural or natural product–derived products, indicat-
ing potency of these scaffolds (Newman et al., 2003). The
unprecedented structures of these molecules make them
excellent synthetic targets, and their potent activity against
a broad number of therapeutic indications makes these
natural products excellent drug lead candidates for new
therapeutics (Newman, 2008). In connection with recent
investigations of Derris indica for value added products
(Rao et al., 2009), we have isolated large quantities of
pongamol (1), which prompted us to synthesize derivatives
and screen for potential anticancer activity. Traditionally,
the fruits and sprouts of this plant are being used in folk
remedies for abdominal tumors in India, the seeds for
keloid tumors in Sri Lanka, and a powder derived from the
plant for tumors in Vietnam. Literature prevalence revealed
that this plant is rich source of Flavonoids and chalcones,
which are known for their anti-cancer and anti-oxidant
properties (Carcahe-Blanco et al., 2003).
Keywords Derris indica ꢀ Chalcones ꢀ
Pyrazole derivatives ꢀ Oxazole ꢀ Anticancer activity
Introduction
Cancer is one of the most serious threats against human
health in the world (Shewach, 2009). Over the past few
decades, extensive research has led to the development of a
plethora of chemotherapeutic agents (Cragg and Newman,
2005; Cragg et al., 2009). The limitations of current anti-
cancer drugs and rapid development of drug resistance
(Sreedhar and Csermely, 2004; Pechan, 1991; McCubrey
et al., 2006) have highlighted the need for the discovery of
R. R. Rao ꢀ K. S. Babu ꢀ P. P. Reddy ꢀ
V. R. S. Rao ꢀ J. M. Rao (&)
Division of Organic Chemistry-I, Natural Products Laboratory,
Indian Institute of Chemical Technology, Hyderabad 500 007,
India
Pongamol (1) belongs to the chalcone class family, in
which two aromatic rings are joined by a three-carbon
a,b-unsaturated carbonyl system, and the wide variety of
pharmacological activities reported includes anti-inflam-
matory, analgesic, antioxidant, antibacterial, antifungal,
and antiprotozoal activities (Gupta and Shaw, 2009).
e-mail: janaswamy@iict.res.in
V. Chaturvedi ꢀ P. Sreekanth ꢀ A. S. Sreedhar (&)
Centre for Cellular and Molecular Biology,
Hyderabad 500 007, India
e-mail: assr@ccmb.res.in
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635
Except in the Traditional system of use, no information is
available on anticancer activity of pongamol. Oxazoles and
pyrazoles are heterocyclic organic compounds that have
five-member ring structure. While oxazole contains 3 car-
bon atoms, an oxygen atom, and 1 nitrogen atoms, pyrazole
contains 3 carbon atoms and 2 nitrogen atoms. The drug
derivatives of oxazole or pyrazole heterocyclic compounds
are reported to enhance drug effectivity (Nakamura et al.,
2003; Nawwar et al., 1994). Therefore, our present study
was focused to evaluate the anticancer effects of pongamol
and its oxazole and pyrazole derivatives. Herein, we report
the synthesis and anticancer activity of the pongamol and
its derivatives using three human tumor cell lines, neuro-
blastoma (IMR-32), T-lymphocytes (Jurkat) and cervical
cancer cells (HeLa). The rationale to select different cell
types was to examine the unique feature and identify the
potential target molecule or pathway in cancer cells.
hydroxylamine hydrochloride in acetic acid at 85°C for 4 h
in acetic acid. Pyrazole derivatives of pongamol (3–12)
were prepared by heating pongamol (1) with various
hydrazines for 8 h in acetic acid [hydrazine hydrate for (3),
phenylhydrazine for (4), 3-fluorophenylhydrazine hydro-
chloride for (5), 2-fluorophenylhydrazine hydrochloride
for (6), 4-fluorophenylhydrazine hydrochloride for (7),
3-nitrophenylhydrazine hydrochloride for (8), 2,4-dinitro-
phenylhydrazine hydrochloride for (9), 2,4-dichlorophenyl-
hydrazine hydrochloride for (10), 4-methoxyphenylhydrazine
hydrochloride for (11), 2-methylphenylhydrazene hydro-
chloride for (12), and 2,4-dimethyl phenyl hydrazine for (13).
All the synthesized derivatives were well characterized by
1
using H NMR, 13C NMR, and HRESI–MS analyses.
Biological activity
Discussion
Chemistry
The IMR-32 cells (1 9 106 cells/ml) were treated with
varying concentrations of pongamol (1) and its synthetic
derivatives (2–13) ranging from 20 to 200 lM for 16 h, and
analyzed by MTT assay. The compounds 1, 4, 10, 11, 13
showed no significant change in cytotoxicity with increased
drug concentrations. However, compounds 2, 3, 5, 6, 7, 8, 9,
12 showed dose-dependent enhancement of cytotox-
icity. Among compounds that showed dose-dependent
Results and discussion
The designed analogues (2–13) were synthesized through
an acid-catalyzed condensation with hydroxyl amine
hydrochloride and various substituted hydrazine hydro-
chlorides (Scheme 1). The isoxazole derivative (2) of
pongamol was synthesized by treatment of pongamol with
O
OMe
i
N
O
2
O
O
OMe
N
OMe
ii
NH
O
OH
3
4. R1 = R2 = R3 = H
1
O
5. R1 = R3 = H, R2 = F
6. R1 = F, R2 = R3 = H
7. R1 = R2 = H, R3 = F
8. R1 = R3 = H, R2 = NO2
9. R1 = R3 = NO2, R2 = H
10. R1 = R3 = Cl, R2 = H
11. R1 = R2 = H, R3 = OMe
12. R1 = CH3, R2 = R3 = H
13. R1 =R3 = CH3, R2 =H
OMe
N
N
iii
R1
R2
R3
(4-13)
Scheme 1 Synthesis of pongamol derivatives. Reagents and condi-
tions: (i) Hydroxylamine hydrochloride, Acetic acid, 85°C, 4 h. (ii)
hydrazine hydrate. (iii) phenylhydrazine; 3-fluorophenylhydrazine
hydrochloride; 2-fluorophenylhydrazine hydrochloride; 4-fluor-
ophenylhydrazine hydrochloride; 3-nitrophenylhydrazine hydrochloride;
2,4-dinitrophenylhydrazine hydrochloride; 2,4-dichlorophenylhydra-
zine hydrochloride; 4-methoxyphenylhydrazine hydrochloride;
2-methylphenylhydrazene hydrochloride; 2,4-dimethylphenylhydra-
zene hydrochloride. Acetic acid/8 h, reflux
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Med Chem Res (2012) 21:634–641
cytotoxicity, compounds 2, 5, and 6 induced a significant
dose-dependent cytotoxicity that has reached to a maximum
of 80% and minimum of 60% at higher concentrations
(Fig. 1a).
Barbacid, 2009). Compounds 2, 5, and 6 are found to be
effective in destabilizing CDK2 in all the three cancer
types, Jurkat, HeLa and IMR-32. Since endoplasmic
reticulum (ER) stress induces and sensitizes cells for cell
cycle independent cytotoxicity (Miki et al., 2009), we
found compounds, 1 and 5 induces ER stress which was
evidenced by the induction of Grp94 (Fig. 3).
Effective anticancer treatments are aimed either to
induce cytostasis or apoptosis, therefore drug-induced cell
cycle arrest is a pre-requisite for energy-dependent cell
killing (Sreedhar et al., 2004; Sreedhar and Csermely,
2004). A dose-dependent cytotoxicity of tumor cells
induced by the pongamol (1) and its derivatives (2–13)
therefore suggested a possible cytostatic effect. The IMR-
32 tumor cells after drug treatments were analyzed by
FACS (fluorescence activated cell sorting), none of the
compounds including 2, 5, and 6 showed drug-induced cell
cycle arrest. However, there is a significant decrease in the
cell number in the G1 phase of cell cycle in cells treated
with compounds 2, 5, 6, and 12 and the massive decrease in
cell number may be related to increased cytotoxicity
(Fig. 1b). Interestingly, none of these drugs were also
found to be effective even to induce G2-M cell cycle block,
on the other hand compounds 1, 2, and 5 showed a decrease
in G2-M population (Fig. 1c).
Compared to normal cells, tumor cells are always
exposed to high selection pressure and constant stress
conditions therefore anticancer drugs that can target either
cell cycle or mitogen signaling can be effective in com-
bating cancer (Sreedhar and Csermely, 2004). However,
we have examined for effect of all Pongamol (1) and its
derivatives (2–13) in normal fibroblast cells, and found that
these drugs do not show any growth inhibitory or cytotoxic
effects (data not presented). We are also evaluating the
cytotoxic effects of these drugs in primary cultures.
Conclusion
In conclusion, we show that among different oxazole and
pyrazole derivatives, the oxazole compound (2), pyrazole
derivatives with fluorine positional variance 5 and 6
showed enhanced cytotoxicity. Among the Pongamol (1)
derivatives, compounds 2, 5, and 6 though showed differ-
ential sensitivity in different cell types in targeting the
ERK1 signaling, however, were all effective in targeting
CDK2, suggesting a potential role for these drugs in tar-
geting the cell cycle.
To examine whether the pongamol and its derivative
drugs-induced effects are cell type specific or not, jurkat
and HeLa cancer cells were treated with 200 lM concen-
tration of compounds 1, 2, 5, and 6 compounds similar to
IMR-32 and the cytotoxicity was assessed. Unlike IMR-32
which showed 38, 58, 86, and 71 cytotoxicity for com-
pounds 1, 2, 5, and 6, HeLa showed 23, 26, 28, and 35 and
Jurkat showed 17, 31, 35, 45 for the same compounds
(Fig. 2a). Although compared to IMR-32 cells, HeLa and
Jurkat showed lesser cytotoxicity, it was found to be sig-
nificant and concentration dependent (data not shown). Cell
cycle analysis of HeLa and Jurkat cells both showed drug-
induced decrease in cells in both G1 and G2-M phase of
cell cycle, which once again may relate to increase in
cytotoxicity upon drug treatments (Fig. 2b, c).
Experimental
General
IR spectra were recorded on Nicolet-740 spectrometer with
KBr Pellets. The 1H and 13C NMR spectra were recorded on
a Bruker FT-300 MHz spectrometer at 300 MHz for 1H and
75 MHz for 13C, respectively, using TMS as internal stan-
dard. The chemical shifts are expressed as (d) values in parts
per million (ppm) and the coupling constants (J) are given in
hertz (Hz). Spin multiplicities are described as s (singlet), br
s (broad singlet), d (doublet), t (triplet), q (quartet), and m
(multiplet). Mass spectra were measured on LC-MSD-Trap-
SL instrument. Melting points were recorded on Electro-
thermal 9100 and are uncorrected. Most of the reaction
solvents were purified by distillation under nitrogen from the
indicating drying agent and used fresh, dichloromethane
(calcium hydride), acetone (potassium permanganate).
Column chromatography was carried out using silica gel
100–200 mesh (Acme Silica gel) and precoated silica gel
plates (Merck, 60 F254) were used for preparative TLC.
Protein kinases are identified as signatures of cancer and
blocking the mitogen signaling molecules has emerged as a
potential anticancer strategy (Sreedhar et al., 2004; Noble
et al., 2004; Gunby et al., 2007). Pongamol (1) and its
derivatives 2, 5, and 6 when tested for anti tyrosine kinase
activity failed to show such activity (data not presented),
for this reason we examined the effect of these compounds
on mitogen signal kinase, ERK1 by immunoblotting. While
compound (2) was effective in destabilizing the ERK1 in
Jurkat, HeLa, and IMR-32, compound (5) was effective
against IMR-32, and compound (6) was effective against
HeLa cells. Similarly, targeting the cell cycle using
selective cell cycle inhibitor drugs is suggested to be
effective anticancer treatment both as single treatment as
well as combinatorial drug treatment (Dancey and Saus-
ville, 2003; Lapenna and Giordano, 2009; Malumbres and
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Med Chem Res (2012) 21:634–641
637
Fig. 1 a The IMR32 cells
showing the percent cell death
induced by pongamol (1) and its
derivatives (2–13). Untreated
and DMSO-treated cells were
used for normalization. b Effect
of pongamol (1) and its
derivatives (2–13) on G1 phase
cell cycle arrest of IMR32 cells.
Control and DMSO-treated cells
were used for reference and
compared with drug-induced
cytostatic effect. c Effect of
pongamol (1) and its derivatives
(2–13) on G2-M phase cell
cycle arrest of IMR32 cells.
Control and DMSO-treated cells
were used for reference and
compared with drug-induced
cytostatic effect
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Med Chem Res (2012) 21:634–641
Fig. 3 Immunoblot analysis of grp94, cdk1, and ERK1 proteins from
the cell lysates made from pongamol (1) and its derivatives (2, 5, and 6)
treated Jurkat, HeLa, and IMR32 cells
Portion of active DCM/MeOH (1:1) extract (50 g) was
subjected to column chromatography (silica gel, 100–200
mesh) using step gradient of hexane, EtOAc, acetone,
CHCl3, MeOH to yield six major fractions (F1–F6). Frac-
tion F1 was subjected to repeated silica gel (100–200
mesh) column chromatography (CC) by eluting with
EtOAc/hexane (10:90) to yield 1.23 g of pongamol.
General procedure for the preparation of (3-(4-
methoxybenzofuran-5-yl)-5-phenylisoxazole (2)
The oxazole analogue was prepared by treating pongamol
0.030 g (1 mmol) with hydroxylamine hydrochloride,
0.008 g (1.2 mmol), in acetic acid at 85°C for 4 h
(Scheme 1). The reaction mixture was evaporated to dry-
ness; residue was dissolved in dichloromethane and washed
with water. The crude product was purified by column
chromatography (hexane: ethyl acetate = 95:5) to afford a
colorless solid (0.020 g, 72%); mp: 105–106°C; IR (KBr):
Fig. 2 a Cytotoxicity of pongamol (1) and its derivatives (2, 5, and 6)
on HeLa and Jurkat tumor cells. Untreated and DMSO-treated cells
were used for normalization. b Effect of pongamol (1) and its
derivatives (2, 5, and 6) on G1 phase cell cycle arrest of HeLa and
Jurkat cells. Control and DMSO-treated cells were used for reference
and compared with drug-induced cytostatic effect. c Effect of
pongamol (1) and its derivatives (2, 5, and 6) on G2-M phase cell
cycle arrest of HeLa and Jurkat cells. Control and DMSO-treated cells
were used for reference and compared with drug-induced cytostatic
effect
1728, 1605, 1468, 1344, 1286, 1235, 1066, 961, 764 cm-1
;
1H NMR (300 MHz, CDCl3): d 7.85 (m, H-2 & H-6), 7.64
(d, J = 8.7 Hz, H-60), 7.60 (d, J = 1.5 Hz, H-200),
7.44–7.36 (m, H-3 & H-50), 7.33–7.26 (m, H-4 & H-5),
6.97 (s, H-300), 6.87 (s, H-a), 4.17 (s, OMe); 13C NMR
(75 MHz, CDCl3): d 167.7, 156.5, 162.7, 150.1, 144.6,
133.4, 133.8, 128.6, 127.7, 125.6, 124.5, 114.4, 107.4,
104.9, 100.1, 60.4; HRESI–MS calcd for C18H14N2O2
[M?H]? 291.0892, found 291.0894.
Extraction and isolation of pongamol from the roots
of Derris indica
The air dried and powdered roots of D. indica (5 kg) were
extracted three times with DCM/MeOH (1:1) for 48 h. The
combined extracts were concentrated under vacuum.
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Med Chem Res (2012) 21:634–641
639
1188, 1150, 966, 869, 769 cm-1
;
1H NMR (300 MHz,
General procedure for the preparation of N-(substituted)
phenyl pongamol pyrazole compounds (3–13)
CDCl3): d 7.90–6.82 (m, H-2 & H-6), 7.57 (br s, H-200),
7.46–7.01 (m, H-60, H-3, H-4, H-5 & 4-Ar–H), 6.88 (m,
H-300 & H-50), 6.73 (s, H-a), 3.67 (s, OMe); 13C NMR
(75 MHz, CDCl3): d 164.2, 160.9, 157.5, 152.0, 150.9,
144.3, 142.6, 141.3, 133.1, 129.6, 129.4, 128.6, 128.0,
127.2, 125.8, 118.7, 115.4, 113.5, 113.2, 111.2, 110.9,
106.9, 106.2, 105.1, 59.2; HRESI-MS calcd for
C24H17FN2O2 [M?H]? 385.1347, found 385.1356.
Pongamol (0.030 g, 1 mmol) was dissolved in glacial acetic
acid (5 ml), and different hydrazine derivatives (1.2 mmol)
(hydrazine hydrate, phenylhydrazine, 3-fluoro phenylhydr-
azine hydrochloride, 2-fluorophenylhydrazine hydrochloride,
4-fluoro phenylhydrazine hydrochloride, 3-nitrophenylhydr-
azine hydrochloride, 2,4-dinitrophenylhydrazine hydrochloride,
2,4-dichlorophenylhydrazine hydrochloride, 4-methoxy-
phenylhydrazine hydrochloride, 2-methylphenylhydrazene
hydrochloride, 2,4-dimethylphenylhydrazene hydrochloride
at 85°C) were added to the solution. The solution was
refluxed for 8 h, and then the solvent was removed in vacuo.
Residue was dissolved in ethyl acetate and washed with
water. Organic portion was collected, dried over sodium
sulfate, and concentrated in vacuo. Crude product was fur-
ther purified by column chromatography. All the products
(3–13) were prepared by using the same procedure.
1-(2-Fluorophenyl)-3-(4-methoxybenzofuran-5-yl)-5-
phenyl-1H-pyrazole (6)
Isolated as a yellow solid. Yield (0.023 g, 60%); mp:
135–136°C; IR (KBr): 1596, 1556, 1509, 1463, 1345,
1
1236, 1067, 963, 762 cm-1; H NMR (300 MHz, CDCl3):
d 7.99 (d, J = 8.6 Hz, H-60), 7.61–7.55 (m, H-200 & H-50),
7.39–7.21 (m, H-2, H-3, H-4, H-5, H-6 & 3-Ar–H),
7.11–7.04 (m, H-a & Ar–H), 6.94 (dd, J = 2.2, 0.9 Hz,
H-300), 4.08 (s, OMe); 13C NMR (75 MHz, CDCl3): d
158.2, 157.1, 154.8, 152.4, 151.0, 144.1, 142.9, 133.2,
129.3, 129.2, 128.8, 128.5, 127.8, 127.0, 125.9, 124.0,
118.6, 116.6, 116.3, 115.3, 106.0, 105.6, 105.0, 59.6;
HRESI-MS calcd for C24H17FN2O2 [M?H]? 385.1347,
found 385.1351.
3-(4-Methoxybenzofuran-5-yl)-5-phenyl-1H-pyrazole (3)
Isolated as a colorless solid (0.022 g, 75%); mp: 129°C; IR
(KBr): 3283, 1725, 1656, 1598, 1545, 1496, 1345, 1284,
1
1230, 1065, 956, 716 cm-1; H NMR (300 MHz, CDCl3):
d 7.95 (d, J = 8.7 Hz, H-60), 7.91–7.83 (m, H-2 & H-6),
7.60 (d, J = 1.9 Hz, H-200), 7.52–7.40 (m, H-3, H-4 &
H-5), 7.32 (d, J = 8.7 Hz, H-50), 7.02 (s, H-a), 6.99 (br s,
H-300), 4.21 (s, OMe); 13C NMR (75 MHz, CDCl3): d
166.9, 162.9, 157.7, 150.9, 144.4, 129.7, 128.9, 128.8,
126.8, 125.7, 124.1, 107.0, 106.7, 105.2, 104.9, 100.6,
100.2, 59.8; HRESI–MS calcd for C18H14N2O2 [M?H]?
291.1128, found 291.1126.
1-(4-Fluorophenyl)-3-(4-methoxybenzofuran-5-yl)-5-
phenyl-1H-pyrazole (7)
Isolated as a yellow solid. Yield (0.026 g, 68%); mp:
139–140°C; IR (KBr): 1641, 1554, 1511, 1465, 1346,
1223, 1151, 1065, 966, 840, 766 cm-1
;
1H NMR
(300 MHz, CDCl3): d 8.01 (d, J = 8.4 Hz, H-60), 7.57 (d,
J = 2.0 Hz, H-200), 7.40–7.22 (m, H-2, H-3, H-4, H-5, H-6,
4 Ar–H), 7.08–7.00 (m, H-50 & H-a), 6.95 (s, H-300), 4.09
(s, OMe); 13C NMR (75 MHz, CDCl3): d 157.4, 156.7,
144.3, 144.0, 128.8, 128.6, 128.5, 128.2, 127.8, 127.3,
126.9, 126.8, 125.8, 125.5, 125.4, 125.3, 115.8, 115.5,
115.2, 108.8, 107.0, 106.4, 106.2, 105.1, 104.9, 60.4, 59.3;
HRESI-MS calcd for C24H17FN2O2 [M?H]? 385.13547,
found 385.1354.
3-(4-Methoxybenzofuran-5-yl)-1,5-diphenyl-1H-pyrazole (4)
Isolated as a colorless solid. Yield (0.024 g, 65%); mp:
156–157°C; IR (KBr): 3285, 3237, 1657, 1545, 1497,
;
1437, 1371, 1303, 1239, 997, 755 cm-1 1H NMR
(300 MHz, CDCl3): d 7.93–7.88 (m, H-2 & H-6), 7.55 (d,
J = 2.3 Hz, H-200), 7.43–7.15 (m, H-60, H-50, H-3, H-4,
H-5, & 5–Ar–H), 6.84 (d, J = 2.0 Hz, H-300), 6.74 (s, H-a),
3.62 (s, OMe); 13C NMR (75 MHz, CDCl3): d 157.3,
151.6, 150.8, 144.2, 141.3, 140.8, 133.2, 128.6 (3C), 128.5
(3C), 127.7, 127.3, 126.7, 125.7 (2C), 123.6 (2C), 106.4,
105.9, 105.0, 59.2; HRESI-MS calcd for C24H18N2O2
[M?H]? 367.1441, found 367.1443.
3-(4-Methoxybenzofuran-5-yl)-1-(3-nitrophenyl)-5-
phenyl-1H-pyrazole (8)
Isolated as a yellow viscous liquid. Yield (0.018 g, 45%);
IR (KBr): 1659, 1588, 1525, 1483, 1353, 1254, 1151, 1037,
1
943, 735 cm-1; H NMR (300 MHz, CDCl3): d 8.36 (t,
1-(3-Fluorophenyl)-3-(4-methoxybenzofuran-5-yl)-5-
J = 2.2 Hz, Ar–H). 8.05 (qd, J = 1.1, 2.0, 3.0 Hz, Ar–H),
7.92 (m, H-2 & H-6), 7.60 (m, H-200 & Ar–H), 7.47–7.30
(m, H-3, H-4, H-5, 2 Ar–H), H-60 & H-50), 6.86 (dd,
J = 2.2, 0.9 Hz, H-300), 6.77 (s, H-a), 4.10 (s, OMe); 13C
NMR (75 MHz, CDCl3): d 156.9, 151.4, 150.4, 148.5,
phenyl-1H-pyrazole (5)
Isolated as a yellow solid. Yield (0.025 g, 65%); mp:
138°C; IR (KBr): 1691, 1612, 1492, 1462, 1344, 1231,
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Med Chem Res (2012) 21:634–641
144.0, 143.7, 141.2, 130.5, 129.8, 129.3, 128.9, 128.8,
125.5, 121.2, 119.6, 118.2, 110.1, 107.1, 104.9, 60.4; ESI-
MS m/z [M ? H]? 411.4.
764 cm-1
;
1H NMR (300 MHz, CDCl3): d 7.89 (d,
J = 8.6 Hz, H-60), 7.56 (d, J = 1.8 Hz, H-200), 7.35–7.16
(m, H-50, H-2, H-3, H-4, H-5, H-6 & 4 Ar–H), 7.09 (s,
H-a), 6.95 (d, J = 1.8 Hz, H-300), 4.09 (s, OMe), 2.07 (s,
Ar–CH3); 13C NMR (75 MHz, CDCl3): d 156.6, 148.9,
151.4, 144.6, 143.9, 139.8, 135.7, 131.0, 130.7, 128.7,
128.4, 127.9, 126.5, 125.6, 119.7, 119.1, 107.0, 106.6,
104.8, 60.4, 29.8; HRESI-MS calcd for C25H20N2O2
[M?H]? 381.1596, found 381.1598.
1-(2,4-Dinitrophenyl)-3-(4-methoxybenzofuran-5-yl)-
5-phenyl-1H-pyrazole (9)
Isolated as a yellow viscous liquid. Yield (0.018 g, 40%);
IR (KBr): 1605, 1535, 1500, 1465, 1343, 1238, 1065, 963,
741 cm-1
;
1H NMR (300 MHz, CDCl3): d 8.68 (d,
J = 2.0 Hz, Ar–H). 8.23 (dd, J = 8.8, 2.2 Hz, Ar–H), 7.82
(m, H-2 & H-6), 7.59 (d, J = 2.0, H-200), 7.42–7.23 (m,
Ar–H, H-60, H-50, H-3, H-4 & H-5), 6.94 (br s, H-300), 6.82
(s, H-a), 3.75 (s, OMe); 13C NMR (75 MHz, CDCl3): d
157.8, 154.2, 145.4, 144.8, 144.1, 142.7, 138.7, 132.0,
129.2, 129.0, 128.7, 127.5, 127.0, 126.4, 126.0, 125.5,
120.7, 113.9, 110.2, 107.7, 107.2, 107.1, 104.8, 60.0;
HRESI-MS calcd for C24H16N4O6 [M ? H]? 457.1143,
found 457.1122.
1-(2,4-Dimethylphenyl)-3-(4-methoxybenzofuran-5-
yl)-5-phenyl-1H-pyrazole (13)
Isolated as a yellow viscous liquid. Yield (0.025 g, 57%);
IR (KBr): 1596, 1491, 1468, 1345, 1235, 1066, 968,
765 cm-1; 1H NMR (300 MHz, CDCl3): d 7.91 (m, H-2 &
H-6), 7.52 (d, J = 2.2 Hz, H-200), 7.36–7.47 (m, H-60, H-3,
H-4, H-5, Ar–H),7.18 (m, H-50 & 2 *Ar–H), 6.96 (d,
J = 2.2 Hz, H-300), 6.77 (s, H-a), 3.85 (s, OMe), 2.08 (s,
Ar–CH3), 2.09 (s, Ar–CH3). ESI-MS m/z [M ? H]? 394.1.
1-(2,4-Dichlorophenyl)-3-(4-methoxybenzofuran-5-yl)-
Acknowledgments Authors gratefully acknowledge keen interest of
Dr. J. S. Yadav, Director, IICT, Hyderabad. RRR thanks to CSIR,
New Delhi for his financial support.
5-phenyl-1H-pyrazole (10)
Isolated as a yellow viscous liquid. Yield (0.024 g, 55%);
IR (KBr): 1597, 1492, 1469, 1346, 1235, 1066, 969,
768 cm-1; 1H NMR (300 MHz, CDCl3): d 7.92 (m, H-2 &
H-6), 7.53 (d, J = 2.2 Hz, H-200), 7.48–7.37 (m, H-60, H-3,
H-4, H-5, Aromatic-1H),7.18 (m, H-50 & 2-Ar–H), 6.96 (d,
J = 2.2 Hz, H-300), 6.77 (s, H-a), 3.85 (s, OMe); 13C NMR
(75 MHz, CDCl3): d 157.2, 156.6, 145.4, 144.2, 144.0,
143.2, 137.0, 132.9, 129.9, 128.5, 128.4, 128.2, 127.9,
127.7, 125.7, 125.3, 119.4, 117.8, 114.4, 107.2, 106.8,
105.8, 105.0, 104.8, 60.3; HRESI-MS calcd for C24H16
Cl2N2O2 [M?H]? 435.0662, found 435.0665.
References
Carcahe-Blanco EJ, Kang A, Park EJ, Su B, Kardono LBS, Riswan S,
Fong HHS, Pezzuto JM, Kinghorn AD (2003) Constituents of the
bark of Pongamia pinnata with the potential to induce quinone
reductase. J Nat Prod 66:1197–1202
Cragg GM, Newman DJ (2005) Plants as a source of anti-cancer
agents. J Ethnopharmacol 100:72–79
Cragg GM, Grothaus PG, Newman DJ (2009) Impact of natural
products on developing new anti-cancer agents. J Chem Rev
109:3012–3043
3-(4-Methoxybenzofuran-5-yl)-1-(4-methoxyphenyl)-
Dancey J, Sausville EA (2003) Issues and progress with protein
kinase inhibitors for cancer treatment. Nat Rev Drug Discov
2:296–313
5-phenyl-1H-pyrazole (11)
Gunby RH, Sala E, Tartari CJ, Puttini M, Gambacorti-Passerini C,
Mologni L (2007) Oncogenic fusion tyrosine kinases as molec-
ular targets for anti-cancer therapy. Anticancer Agents Med
Chem 7:594–611
Gupta M, Shaw BP (2009) Uses off medicinal plants in panchakarma
ayurvedic therapy. Indian J Tradit Knowl 8:372–378
Koehn FE, Carter GT (2005) The evolving role of natural products in
drug discovery. Nat Rev Drug Discov 4:206–220
Lapenna S, Giordano A (2009) Cell cycle kinases as therapeutic
targets for cancer. Nat Rev Drug Discov 8:547–566
Lloyd DG, Golfis G, Knox AJS, Fayne D, Meegan MJ, Oprea TI
(2006) Oncology exploration: charting cancer medicinal chem-
istry space. Drug Discov Today 11:149–159
Isolated as a yellow viscous liquid. Yield (0.014 g, 35%); IR
(KBr): 1596, 1466, 1346, 1242, 1068, 910, 802, 765 cm-1
;
1H NMR (300 MHz, CDCl3): d 7.90 (m, H-2 & H-60), 7.56
(d, J = 2.0 Hz, H-200), 7.18–7.43 (m, H-50, H-2, H-3, H-4,
H-5, H-6 & 2 Ar–H), 6.86 (d, J = 2.0 Hz, H-300), 6.77 (d,
J = 8.8 Hz, 2 Ar–H), 6.72 (s, H-a), 3.76 (s, OMe), 3.69 (s,
OMe); 13C NMR (CDCl3, 75 MHz): d 144.1, 134.4, 133.5,
128.5, 127.6, 127.5, 125.8, 125.2, 113.7, 106.1, 106.0, 105.1,
59.5, 55.2; ESI-MS m/z [M?H]? 397.6.
Malumbres M, Barbacid M (2009) Cell cycle, CDKs and cancer: a
changing paradigm. Nat Rev 9:153–166
McCubrey JA, Steelman LS, Abrams SL, Lee JT, Chang F, Bertrand
FE, Navolanic PM, Terrian DM, Franklin RA, D’Assoro AB,
Salisbury JL, Mazzarino MC, Stivala F, Libra M (2006) Roles of
the RAF/MEK/ERK and PI3K/PTEN/AKT pathways in
3-(4-Methoxybenzofuran-5-yl)-5-phenyl-1-o-tolyl-1H-
pyrazole (12)
Isolated as a yellow viscous liquid. Yield (0.016 g, 42%);
IR (KBr): 1599, 1500, 1414, 1241, 1186, 1147, 1065, 969,
123

Med Chem Res (2012) 21:634–641
641
malignant transformation and drug resistance. Adv Enzyme
Regul 46:249–279
Noble MEM, Endicott JA, Johnson LN (2004) Protein kinase
inhibitors. Science 303:1713–1928
Miki T, Miura T, Hotta H, Tanno M, Yano T, Sato T, Terashima Y,
Takada A, Ishikawa S, Shimamoto K (2009) Endoplasmic
reticulum stress in diabetic hearts abolishes erythropoietin-
induced myocardial protection by impairment of phospho-
glycogen synthase kinase-3beta-mediated suppression of mito-
chondrial permeability transition. Diabetes 58:2863–2872
Nakamura T, Sato M, Kakinuma H, Miyata N, Taniguchi K, Bando K,
Koda A, Kameo K (2003) Pyrazole and isoxazole derivatives as
new, potent, and selective 20-hydroxy-5,8,11,14-eicosatetrae-
noic acid synthase inhibitors. J Med Chem 46:5416–5427
Nawwar GA, Swellem RH, Ibrahim AM (1994) Oxazole, pyrazole
and piperidine derivatives having an o-hydroxyaryl moiety with
anticipated molluscicidal activity. Arch Pharm Res 17:66–70
Newman DJ (2008) Natural products as leads to potential drugs: an
old process or the new hope for drug discovery? J Med Chem
51:2589–2599
Pechan PM (1991) Heat shock proteins and cell proliferation. FEBS
Lett 280:1–4
Rao RR, Tiwari AK, Reddy PP, Babu KS, Ali AZ, Madhusudana K,
Rao JM (2009) New furanoflavanoids, intestinal alpha-glucosi-
dase inhibitory and free-radical (DPPH) scavenging activity
from antihyperglycemic root extract of Derris indica (Lam.).
Bioorg Med Chem 17:5170–5175
Shewach DS (2009) Introduction to cancer chemotherapeutics. Chem
Rev 109:2859–2861
Sreedhar AS, Csermely P (2004) Heat shock proteins in the regulation
of apoptosis: new strategies in tumor therapy. A comprehensive
review. Pharmacol Ther 101:227–257
Sreedhar AS, Soti C, Csermely P (2004) Inhibition of Hsp90: a new
strategy for inhibiting protein kinases. Biochim Biophys Acta
1697:233–242
Newman DJ, Cragg GM, Snader KM (2003) Natural products as
sources of new drugs over the period 1981–2002. J Nat Prod
66:1022–1037
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