Synthesis and in vitro cytotoxicity study of 3-(1H-indol-3-yl)-1,3- diphenylpropan-1-ones

Article abstract of DOI:10.1007/s00044-013-0875-y

A series of 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones 3a-l were synthesized in good to excellent yield by Michael addition of indole 1 with α,β-unsaturated ketones 2a-l in presence of indium(III) sulphate (20 mol%). The structure of the title compounds were established by ¹H NMR, ¹³C NMR, mass and elemental analysis. All the synthesized compounds were evaluated for in vitro cytotoxicity against five different cancer cell lines such as ACHN (human kidney adenocarcinoma), Panc1 (pancreatic), Calu1 (lung), H460 (non small cell lung), HCT116 (human colon cancer cell) and MCF10A (normal breast epithelium) using propidium iodide staining assay protocol. The result showed that the compounds 3e and 3l have excellent cytotoxic activity with the IC₅₀ value ranging from 1.4-2.7 to 2.4-3.4 μM, respectively, in comparison with the other compounds, Flavopiridol and Gemcitabine were employed as a positive control. The findings conferred 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones seem to be promising candidates for the development of new anticancer drugs.

Full text of DOI:10.1007/s00044-013-0875-y

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-013-0875-y
ORIGINAL RESEARCH
Synthesis and in vitro cytotoxicity study of 3-(1H-indol-3-yl)-1,3-
diphenylpropan-1-ones
•
Jagadeesh N. Masagalli Kittappa M. Mahadevan
•
•
Honnali Jayadevappa Hosanagara N. Harishkumar
•
•
Rajesha Ganalu Prashantha Nagaraja
Received: 9 June 2013 / Accepted: 7 November 2013
Ó Springer Science+Business Media New York 2013
Abstract A series of 3-(1H-indol-3-yl)-1,3-diphenylpro-
pan-1-ones 3a–l were synthesized in good to excellent
yield by Michael addition of indole 1 with a,b-unsaturated
ketones 2a–l in presence of indium(III) sulphate
(20 mol%). The structure of the title compounds were
findings conferred 3-(1H-indol-3-yl)-1,3-diphenylpropan-
1-ones seem to be promising candidates for the develop-
ment of new anticancer drugs.
Keywords Michael addition ꢀ Indium(III) sulphate ꢀ
Indole ꢀ Friedel–Crafts alkylation ꢀ Cytotoxic activity ꢀ
SAR analysis
1
established by H NMR, 13C NMR, mass and elemental
analysis. All the synthesized compounds were evaluated
for in vitro cytotoxicity against five different cancer cell
lines such as ACHN (human kidney adenocarcinoma),
Panc1 (pancreatic), Calu1 (lung), H460 (non small cell
lung), HCT116 (human colon cancer cell) and MCF10A
(normal breast epithelium) using propidium iodide staining
assay protocol. The result showed that the compounds 3e
and 3l have excellent cytotoxic activity with the IC50 value
ranging from 1.4–2.7 to 2.4–3.4 lM, respectively, in
comparison with the other compounds, Flavopiridol and
Gemcitabine were employed as a positive control. The
Introduction
Indole nucleus has been a structural subunit of many nat-
ural and pharmaceutical agents (Kameshwara et al., 2011;
Abdel-Rahman, 2010). In addition, several indole deriva-
tives have been found to exhibit anticancer (Ekhlass, 2010;
Vishal et al., 2012; Chen et al., 1996), antioxidant (Suzen
and Buyukbingol, 2000), antirhemuatoidal and anti-HIV
(Buyukbingol et al., 1994; Suzen and Buyukbingol, 1998)
activities. Natural product (?)-(S)-kurasoin B (1), ana-
logues of 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones
isolated from soil fungus Paecilomyces sp. (FO-3684) has
been reported as selective inhibitors of farnesyltransferase
(Rodney and Fernandes, 2008). Magdy and Atef (2009)
and Magdy et al. (2010) studied that indolylchalcones were
found to be promising candidates for in vitro antitumor
activity, as they were previously reported to posses anti-
cancer, immunosuppressant and therapeutic activities for
autoimmune diseases (Shum-ichi et al., 1999). Various
indolylchalcones containing methoxy group exhibits potent
and selective anticancer activity (Dalip et al., 2010). More
recently 3-(5-methoxy,2-methyl-1H-indol-3-yl)-1-(4-py-
ridinyl)-2-propen-1-one (2) served as a novel molecule for
methuosis (a type of nonapoptotic cell death) (Michael
et al., 2012).
Electronic supplementary material The online version of this
article (doi:10.1007/s00044-013-0875-y) contains supplementary
material, which is available to authorized users.
J. N. Masagalli ꢀ K. M. Mahadevan (&) ꢀ H. N. Harishkumar
Department of Post Graduate Studies and Research in
Chemistry, School of Chemical Sciences, Kuvempu University,
Shankaraghatta 577 451, Karnataka, India
e-mail: mahadevan.kmm@gmail.com
H. Jayadevappa
Department of Chemistry, Sahyadri Science College
(Autonomous), Shimoga 577 203, Karnataka, India
R. Ganalu
BETAHE, Bharathi College, Bharathinagara, Maddur,
Mandya 571 422, Karnataka, India
P. Nagaraja
Scientific Bio-Minds, Bangalore 560 092, Karnataka, India
123

Med Chem Res
N
sulphate (10, 20, 30 and 50 %) with different solvent under
reflux temperature. In our observations, 20 mol% of the
indium(III) sulphate in ethanol was sufficient for the synthesis
of 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones with high
yield (Table 1). The variation in the percentage of indium(III)
sulphate had only marginal difference in the yields and reac-
tions time. Hence 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-
ones 3a–l, (Scheme 1, Table 2) were synthesized via two
component one pot reaction of Indole 1 with different a,b-
unsaturated ketones 2a–l in presence of 20 mol% Indium(III)
sulphate in ethanol.
O
O
O
OH
N
H
N
H
MOMIPP (2)
(+)-(S)-kurasoin B (1)
The structure of compounds 1 and 2 resembles our syn-
thesized compounds, which prompted us to carry out their
in vitro cytotoxicity studies. This study was supported by our
previous study on investigation of new anticancer molecules
(Bindu et al., 2012a, b). Hence, herein we report the synthesis
and cytotoxic studies of 3-(1H-indol-3-yl)-1,3-diphenylpro-
pan-1-ones 3a–l. The cytotoxic study was carried out in vitro
against five human cancer cell lines such as ACHN, Panc1,
Calu1, H460 and HCT116. The normal breastepithelium cells
(MCF10A) were used to identify the selectivity of the com-
pounds towards highly proliferating cancer cells. Although
many methods have been reported to prepare various 3-(1H-
indol-3-yl)-1,3-diphenylpropan-1-ones (Brindaban et al.,
2005; Bimal et al., 2005; Bei-Yao et al., 2010; Arrigo et al.,
2009; Jianwei et al., 2010; Xiang et al., 2011; Zhi-Liang et al.,
2008), these methods suffer due to some draw backs such as
low yield, long reaction time, solubility of the catalyst in
solvents make difficulty in isolation of the products, their
reusability and chance of polymerization or dimerization of
the reactants. In this context, it is worthy to note that the
indium(III) sulphate is an effective milder Lewis acid catalyst
which offers the conjugate addition of indole to a,b-unsatu-
rated ketones smoothly to give goodyield and also the catalyst
could be recycled and reused two to three times without the
loss of its catalytic activity.
The relevance in using indium(III) sulphate for conjugate
addition is of its insolubility in ethanol as compared with
indium(III) chloride and indium(III) bromide as they are
soluble and cannot be reusable (Brindaban et al., 2005; Bimal
et al., 2005; Bei-Yao et al., 2010). Thus indium(III) sulphate
catalysed method found to be economical and efficient. Easy
isolationof the products and the recovery of the catalyst make
itenvironmentalfriendlyprocedure. Hence, weoptimizedthe
amount of indium(III) sulphate i.e. 20 mol% of the catalyst
was only used in entire reaction and evaluated the reusability
of catalyst in the model reaction 3a. Accordingly, we tested
the reusability in which the 20 mol% catalyst was taken for
the first reaction was filtered, washed with EtOH, oven dried
andreusedfor thereactiontogetsatisfactoryyieldof92 %. In
the third run of catalyst, yield was 89 %.
The catalytic activity of In2(SO4)3 in the conjugated
addition of indole to a,b-unsaturated ketones 2a–l is as
Table 1 Effect of solvent and catalyst on reaction time and yield
Entry Solvent
In2(SO4)3 (mol%) Time (h) Yield (%)a
1
2
3
4
5
6
a
Ethanol
Ethanol
Ethanol
Ethanol
Methanol
10
20
30
50
10
6
85
94
90
91
82
30
6
6
6
Results and discussion
6
Acetonitrileb 10
6–20
Chemistry
Yield after column chromatography
Initially, the conjugate addition of indole to a,b-unsaturated
ketones was carried out by varying percentage of indium(III)
b
Not a good solvent since many undesired side products were
observed by TLC
Scheme 1 Synthesis of 3-(1H-
indol-3-yl)-1,3-diphenylpropan-
1-ones 3a–l
R
R
3
1
R
4
R
R
O
2
3
R
5
R
2
In (SO )
4 3
20 mol %
2
+
N
H
EtOH/Reflux on water bath
5-6 hr
O
R
R
R
5
1
4
N
H
1
2(a-l)
3(a-l)
R3= OMe
R4= F, OMe
R1= H, F, Cl, OMe
R2= F, Cl
R5= H, OMe, F, Cl, Br
123

Med Chem Res
Table 2 In2(SO4)3 mediated conjugate addition of indole with a,b-unsaturated ketones
Entry
Productsa
Time (h)
6
Yield (%)b
94
M.P/L (oC)
118–120
F
3a
O
F
N
H
3b
6
89
115–117/117–119
O
Cl
N
H
F
3c
6
90
220–221
O
Cl
N
H
Cl
3d
6
87
70–73
O
F
N
H
123

Med Chem Res
Table 2 continued
Entry
Productsa
Time (h)
6
Yield (%)b
90
M.P/L (oC)
221–225
Cl
3e
O
O
O
Cl
Cl
F
N
H
MeO
3f
5
6
6
91
85
91
198–200/204–205
N
H
Br
3g
160–162
N
H
Br
3h
183–185
O
Cl
N
H
123

Med Chem Res
Table 2 continued
Entry
Productsa
Time (h)
6
Yield (%)b
90
M.P/L (oC)
MeO
3i
177–179/172–175
O
F
N
H
3j
5
88
200–202
O
OMe
OMe
N
H
Cl
3k
6
87
156–159
F
O
F
N
H
MeO
3l
6
89
198–201
OMe
OMe
O
N
H
All reactions were carried out at reflux temperature using 20 mol% In2(SO4)3 in ethanol
a
1
All products were characterized by H and 13C NMR and mass spectroscopy
b
Isolated yields
Biological activity
shown in Scheme 2. Initially the molecule of In2(SO4)3
attack the carbonyl oxygen to produce intermediate II.
Thus the 1,4-conjugate addition of indole at 3rd position
was facilitated which led to the formation of III. Subse-
quently, the intermediate III underwent cleavage to furnish
the final product V (Marco et al., 2002).
The synthesized 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-
ones 3a–l were tested for their in vitro cytotoxic effect against
five cancer cell lines such as ACHN, Panc1, Calu1, H460
HCT116 and MCF10A. Gemcitabine and Flavopyridol were
123

Med Chem Res
Scheme 2 The plausible
reaction mechanism for the
Indium(III) sulphate catalysed
Michael addition reaction
H
_
N+
_
_
In (SO
)
In (SO
2
)
2
4 3
4 3
In (SO )
4 3
-
2
. .
O
O+
In (SO
2
)
Nu:
4 3
O
O
H
+
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
I
III
II
_
_
HN
HN
Ph
In (SO
)
4 3
-H+
2
-
Nu:
O
=
O
N+
H
In (SO
)
4 3
2
Ph
Ph
Ph
IV H+
V
employed as positive control. According to the PI staining
assay, the IC50 (the concentration of compound required to
inhibit 50 % of cell growth) was determined. The results are
summarized in Table 3.
(1H-indol-3-yl)propan-1-one 3e and methoxy substituent in
3-(2,4-dimethoxyphenyl)-3-(1H-indol-3-yl)-1-(4-methoxy-
phenyl)propan-1-one 3l are the probable lead molecules
which significantly act against cancer cell lines.
As shown in Table 3 most of the tested compounds showed
moderate to high cytotoxic activity against ACHN, Panc1,
Calu1, H460 andHCT116cell lines. It was note worthy thatthe
cytotoxic effect was more pronounced against H460 cell line
compared with other cell line, wherein IC50 values at
1.7–4.8 lM in comparison with positive control Gemcitabine
at 0.27 lM and Flavopyridol at 0.58 lM, respectively.Among
the tested compounds 3a–l, the compound 3e having chloro
groups and compound 3l with methoxy groups are found to be
the most promising compounds in this series when compared
to positive control. Furthermore, the compound 3e showed
high potent activity against Panc1, Calu1, H460 cell line with
IC50 values at 1.4, 1.8 and 1.7 lM which was comparable with
positive control Gemcitabine at 0.34, 0.45, 0.27 lM and
Flavopyridol at 0.56, 0.64, 0.58 lM, respectively.
Experimental
Chemistry
The chemicals and reagents obtained from HiMedia, Sigma-
Aldrich Chemical Company were used as received. Melting
points were uncorrected, determined in open capillary.
Purity of the compounds was checked by TLC on silica gel,
and compounds were purified by using column chromatog-
raphy. FTIR spectra were recorded in KBr pellet using Shi-
madzu-8400S spectrometer in the range 400–4,000 cm-1
,
1H NMR and 13C NMR spectra were recorded on a Bruker
supercon FT NMR (400 MHz) spectrometer in CDCl3 or
DMSO-d6 and TMS as an internal standard. The chemical
shifts are expressed in d units. Mass spectra were recorded on
a JEOL SX 102/DA-6000 (10 kV) FAB mass spectrometer.
The purity of the compound is between 96 and 100 %.
Also found that the compounds 3a–d and positive con-
trol exhibited less cytotoxicity against the normal MCF10A
cell line at IC50 [ 10 lM. whereas the compounds 3e–
l showed moderate cytotoxic effect with IC50 values at
2.1–8.7 lM on normal MCF10A cell line.
Typical procedure for the synthesis of 1,3-bis(4-
The structural activity relationship (SAR) analysis of com-
pounds 3a–l containing chloro, fluoro, bromo and methoxy
functional groups in phenyl rings at C2, C3, C4 and C6 posi-
tions shows cytotoxic effect on cancer and normal cell lines are
listed in Table 3. The resultant values of each compound
depend on their functional groups which show moderate to high
inhibitory activity in all cancer cell lines with reference to
Gemcitabine and Flavopiridol with % SAR activation of 0.434
and 0.52 respectively. Since the synthesized compounds 3a–
d and 3f–k show high to moderate % SAR activation compare
to standard drugs no significant activity found on tested cancer
cell lines (Fig. 1). The % SAR activation value of compounds
3e having chloro substitution and compound 3l with methoxy
substitution lies in the range of standard drug i.e. 0.460 and
0.407 respectively shows significant anti cancer effect on tested
cell lines. Finally it has been concluded that the target com-
pounds having chloro substituent in 1,3-bis(4-chlorophenyl)-3-
fluorophenyl)-3-(1H-indol-3-yl)propan-1-one (3a)
To the stirred solution of chalcone (0.25 g, 1 mmol), indole
(0.12 g, 1 mmol) in ethanol (5 mL) was added indium(III)
sulphate (0.10 g, 20 mol%) and the reaction mixture was
refluxed on water bath until completion of the reaction as
indicated by TLC (pet ether/ethyl acetate 8:2 v/v). The
catalyst was recovered by filtration and washed with eth-
anol (3 9 3 mL), dried in oven. Then the combined filtrate
was quenched with water and extracted with ethyl acetate
(10 9 3 mL). The organic phase was combined, dried over
anhyd Na2SO4. Evaporation of organic phase offered crude
product which was then purified by column chromatogra-
phy over silica gel (pet ether/ethyl acetate 8:2 v/v) and
recrystallization from ethanol to get pure product 3a
(0.349 g, 94 %), as crystalline solid, mp 118–120 °C.
Similarly remaining compounds (3b–l) were also prepared.
123

Med Chem Res
Table 3 In vitro cytotoxic activities of compounds 3a–f, against five cancer and normal MCF10A cell lines
Compound
Cell line (IC50, lM SD)
SAR analysis
ACHN
Panc1
Calu1
H460
HCT116
MCF10A
(% of activation)
3a
3b
3c
3d
3e
3f
6.3 2.82
3.3 0.18
5.9 2.42
3.7 0.22
2.3 1.18
3.1 0.38
3.8 0.32
2.9 0.58
4.3 0.82
3.2 0.28
3.4 0.08
2.6 0.88
4.3 1.08
4.4 1.18
3.8 0.58
3.2 0.01
1.4 1.81
3.2 0.01
4.1 0.88
4.2 0.98
5.1 1.88
2.7 0.51
2.4 0.81
2.4 0.81
4.5 1.16
5.4 2.06
3.6 0.26
3.3 0.03
1.8 1.53
3.4 0.06
3.4 0.06
3.7 0.36
4.6 1.26
3.1 0.23
3.2 0.13
2.7 0.63
2.4 0.62
4.0 1.57
3.6 0.57
3.6 0.57
1.7 1.32
3.3 0.27
2.9 0.12
4.8 1.77
2.6 0.42
3.5 0.47
2.7 0.32
3.1 0.07
5.2 1.53 [10 3.2 0.970
4.7 1.03 [10 3.2 0.831
4.3 0.63 [10 3.2 0.933
4.2 0.53 [10 3.2 0.807
2.7 0.97
3.5 0.17
4.5 0.83
4.8 1.13
3.1 0.57
3.8 0.13
2.8 0.87
3.4 0.27
6.8
0
0.460
8.7 1.9 0.756
6.5 0.3 0.768
4.6 2.2 0.886
3.9 2.9 0.816
2.7 4.1 0.806
3.1 3.7 0.223
2.1 4.7 0.407
3g
3h
3i
3j
3k
3l
Positive control 1 Gemcitabine 0.17 3.29 0.34 2.85 0.45 2.87 0.27 2.73 0.24 3.39 [10 3.2 0.434
Positive control 2 Flavopiridol
0.45 3.03 0.56 2.65 0.64 2.69 0.58 2.44 0.72 2.95 [10 3.2 0.52
Spectral data
3-(4-Chlorophenyl)-1-(4-fluorophenyl)-3-(1H-indol-3-yl)
propan-1-one (3c) IR (KBr): m 3386, 2923, 1658,
1,3-Bis(4-fluorophenyl)-3-(1H-indol-3-yl)propan-1-one
(3a) IR (KBr): m 3402, 2923, 1666, 1010 cm-1, 1H NMR
(400 MHz, DMSO-d6) d: 10.86 (s, 1H), 8.12–8.08 (m, 2H),
7.45–7.41 (m, 3H), 7.36–7.30 (m, 4H), 7.06–7.01 (m, 3H),
6.90 (t, J = 1.8 Hz, 1H), 4.87 (t, J = 1.8 Hz, 1H), 3.91
(dd, J = 7.2, 7.2 Hz, 1H), 3.81 (dd, J = 8.0, 8.0 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d: 197.4 (CO–C1), 168.6
(C4–Ar1), 168.0 (C4–Ar3), 136.8 (C1–Ar1), 134.8 (C1–Ar3),
131.5 (C9–Ind), 131.5 (C3,5–Ar1), 131.4, 130.0 (C2,6–Ar3,
C2,6–Ar1), 126.7, 122.3, 121.9, 119.0, 118.7, 114.9, 111.8
(C8,2,5,6,4,3,7–Ind), 45.3 (CH–C3), 37.7 (CH2–C2). MS:
m/z = 360.1 (M?), 361.1 (M?1). Elemental analysis calcd
for C23H17F2NO = C, 76.44, H, 4.74, N, 3.88 % Found C,
76.14, H, 4.79, N, 3.81 %.
1087 cm-1,1H NMR (300 MHz, DMSO-d6) d: 10.90 (s,
1H), 8.06–8.12 (m, 2H), 7.25–7.43(m, 9H), 7.00–7.05 (m,
1H), 6.87–6.92 (m, 1H), 4.86 (t, J = 7.20 Hz, 1H), 3.92
(dd, J = 6.9, 17.4 Hz, 1H), 3.82 (dd, J = 7.8, 17.4 Hz,
1H). 13C NMR (300 MHz, DMSO-d6) d: 197.2 (CO–C1),
167.1 (C4–Ar1), 163.8 (C4–Ar3), 144.7 (C1–Ar3), 136.8
(C9–Ind), 134.0 (C2,6–Ar1), 131.5 (C1–Ar1), 131.4 (C2,6
–
Ar3), 130.1, 130.7 (C3,5–Ar1, C3,5–Ar3), 128.4, 122.4, 121.5,
119.0, 118.0, 115.9, 111.8 (C8,2,5,6,4,3,7–Ind), 44.4 (CH–C3),
37.4 (CH2–C2). MS: m/z = 376.2 (M-1). Elemental analysis
calcd for C23H17ClFNO = C, 73.11, H, 4.54, N, 3.71 %
Found C, 73.09, H, 4.59, N, 3.68 %.
1-(4-Chlorophenyl)-3-(4-fluorophenyl)-3-(1H-indol-3-yl)
propan-1-one (3d) IR (KBr): m 3409, 2922, 1666,
3-(4-Chlorophenyl)-3-(1H-indol-3-yl)-1-phenylpropan-1-
one (3b) (Chauan-Ji and Chen-Jiang, 2010) 1H NMR
(300 MHz, CDCl3) d: 8.00 (s, 1H), 7.78 (d, J = 8.55 Hz,
2H), 7.58 (d, J = 8.58 Hz, 2H), 7.26–7.41 (m, 3H), 7.17 (t,
J = 8.07 Hz, 1H), 7.04 (t, J = 7.92 Hz, 1H), 6.92–6.95
(m, 4H), 5.03 (t, J = 7.14 Hz, 1H), 3.77 (dd, J = 6.45,
16.62 Hz, 1H), 3.65 (dd, J = 8.01, 16.59 Hz, 1H). 13C
NMR (300 MHz, CDCl3) d: 197.3 (CO–C1), 135.6 (C1–
Ar1), 131.8 (C9–Ind), 129.5, 129.2 (C3,5–Ar3, C2,6–Ar1), 129.0,
128.2 (C2,6–Ar3, C3,5–Ar1), 126.3, 122.2, 121.1, 119.5, 119.3,
115.0, 111.1 (C8,2,5,6,4,3,7–Ind), 45.0 (CH–C3), 37.4 (CH2–C2).
MS: m/z = 361.1 (M?1). Elemental analysis calcd for
C23H18ClNO = C, 76.77, H, 5.04, N, 3.89 % Found C, 76.69,
H, 5.01, N, 3.81 %.
1
1234 cm-1, H NMR (300 MHz, DMSO-d6) d: 10.88 (d,
J = 12.90 Hz, 1H), 8.03 (d, J = 8.40 Hz, 2H), 7.57 (d, J =
8.40 Hz, 2H), 7.27–7.45 (m, 5H), 7.04 (t, J = 8.40 Hz, 3H),
6.88 (q, J = 12.90 Hz, 1H), 4.88 (t, J = 7.20 Hz, 1H), 3.94
(dd, J = 6.9, 17.1 Hz, 1H), 3.81 (dd, J = 7.8, 17.4 Hz, 1H).
13C NMR (300 MHz, DMSO-d6) d: 197.8 (CO–C1), 162.5
(C4–Ar3), 159.3 (C4–Ar1), 141.7 (C2,6–Ar1), 138.5 (C3,5
–
Ar1), 136.8 (C9–Ind), 135.9 (C1–Ar3), 130.4 (C1–Ar1), 130.0
(C3,5–Ar3), 129.9 (C2,6–Ar3), 126.7, 122.4, 121.5, 119.1,
118.7, 115.0, 111.8 (C8,2,5,6,4,3,7–Ind), 44.7 (CH–C3), 37.3
(CH2–C2). MS: m/z = 376.8 (M-1). Elemental analysis
calcd for C23H17ClFNO = C,73.11, H,4.54, N,3.71 % Found
C, 73.15, H, 4.58, N, 3.68 %.
123

Med Chem Res
Fig. 1 % SAR activation of
synthesized compounds 3a–f in
comparison with positive
control Gemcitabine and
Flavopiridol
1,3-Bis(4-chlorophenyl)-3-(1H-indol-3-yl)propan-1-one
(3e) IR (KBr): m 3448, 2930, 1681, 1095 cm-1, 1H NMR
(300 MHz, CDCl3) d: 8.03 (s, 1H), 7.86 (d, J = 8.52 Hz,
2H), 7.41 (q, J = 2.55 Hz, 3H), 7.37 (q, J = 8.55 Hz, 2H),
7.11–7.15 (m, 4H), 5.03 (t, J = 7.02 Hz, 1H), 3.78 (dd,
J = 6.39, 16.77 Hz, 1H), 3.66 (dd, J = 8.04, 16.8 Hz, 1H).
13C NMR (300 MHz, DMSO-d6) d: 197.3 (CO–C1), 161.5
7. 77 (d, J = 8.8 Hz, 2H), 7.57 (d, J = 8.8 Hz, 2H), 7.39–
7.26 (m, 4H), 7.18–7.14 (m, 1H), 7.05–6.91 (m, 4H), 5.02 (t,
J = 7.2 Hz, 1H), 3.77 (dd, J = 6.4 16.8 Hz, 1H), 3.65 (dd,
J = 7.6, 16.8 Hz, 1H). 13C NMR (400 MHz, CDCl3) d:
197.3 (CO–C1), 139.6 (C3,5–Ar1), 136.6 (C9–Ind), 135.8
(C1–Ar1), 131.9 (C2,6–Ar1), 129.5 (C2,6–Ar3), 128.2 122.3,
121.2, 119.5, 119.1, 115.1, 111.2 (C8,2,5,6,4,3,7–Ind), 45.1
(CH–C3), 37.6 (CH2–C2). MS: m/z = 422.2 (M?), 423.3
(M?1). Elemental analysis calcd for C23H17BrFNO = C,
65.42, H, 4.06, N, 3.32 % Found C, 65.36, H, 4.11, N, 3.36.
(C4–Ar1), 158.9 (C4–Ar3), 141.8 (C3,5–Ar1), 141.6 (C3,5
–
Ar3), 139.4 (C1–Ar3), 134.9 (C1–Ar1), 136.3 (C9–Ind), 130.9
(C2,6–Ar3), 131.0 (C2,6–Ar1), 129.9, 121.9, 117.5, 117.4,
116.8, 115.5, 110.3 (C8,2,5,6,4,3,7–Ind), 44.6 (CH–C3), 37.8
(CH2–C2). MS: m/z = 396.0 (M?2). Elemental analysis
calcd for C23H17Cl2NO = C, 70.06, H, 4.35, N, 3.55 %
Found C, 70.11, H, 4.40, N, 3.47 %.
1-(4-Bromophenyl)-3-(2-chlorophenyl)-3-(1H-indol-3-yl)
propan-1-one (3h) IR (KBr): m 3409, 2923, 1681,
1
1095 cm-1, H NMR (400 MHz, CDCl3) d: 8.02 (s, 1H),
7. 89 (d, J = 8.4 Hz, 2H), 7.78 (d, J = 8.8 Hz, 2H), 7.72
(s, 1H), 7.67–7.56 (m, 5H), 7.49–7.45 (m, 3H), 5.02 (t, J =
7.2 Hz, 1H), 3.76 (dd, J = 6.4, 16.8 Hz, 1H), 3.64 (dd,
J = 8, 16.4 Hz, 1H). 13C NMR (400 MHz, CDCl3) d: 197.8
(CO–C1), 139.8 (C1–Ar3), 136.6 (C9–Ind), 136.3 (C1–Ar1),
135.7 (C3,5–Ar1), 131.6 (C2,6–Ar1), 129.7 (C4–Ar3), 128.7
(C3,5–Ar3), 128.4 (C2–Ar3), 127.6, 123.2, 121.8, 119.3, 118.9,
115.4, 111.0 (C8,2,5,6,4,3,7–Ind), 45.4 (CH–C3), 37.9 (CH2–
C2). MS: m/z = 439.8 (M?1). Elemental analysis calcd for
C23H17BrClNO = C, 62.96, H, 3.91, N, 3.19 % Found C,
62.99, H, 3.88, N, 3.23 %.
3-(4-Chlorophenyl)-3-(1H-indol-3-yl)-1-(4-methoxyphenyl)
propan-1-one (3f) (Chauan-Ji and Chen-Jiang, 2010) 1H
NMR (400 MHz, CDCl3) d: 7.99 (s, 1H), 7.91–7.94 (d, J =
12 Hz, 2H), 7.00–7.41 (m, 9H), 6.90–6.93 (d, J = 12 Hz,
2H), 5.04 (t, J = 7.16 Hz, 1H), 3.00 (dd, J = 6.4, 6.36 Hz,
1H), 3.65 (dd, J = 8.08, 8.08 Hz, 1H), 3.87 (s, 3H). 13C
NMR (400 MHz, CDCl3) d: 197.8(CO–C1), 161.5 (C4–Ar1),
158.9 (C4–Ar3), 141.8 (C3,5–Ar3), 141.6 (C3,5–Ar1), 139.4
(C1–Ar3), 134.9 (C1–Ar1), 136.3 (C9–Ind), 130.9 (C2,6–Ar1),
131.0 (C2,6–Ar3), 129.9, 127.0, 117.5, 117.4, 116.8, 115.5,
110.3 (C8,2,5,6,4,3,7–Ind), 55.8 (OCH3), 44.6 (CH–C3), 37.8
(CH2–C2). MS: m/z = 412.3 (M?23). Elemental analysis
calcd for C24H20ClNO2 = C, 73.94, H, 5.17, N, 3.59 %
Found C, 73.89, H, 5.21, N, 3.63 %.
3-(4-Fluorophenyl)-3-(1H-indol-3-yl)-1-(4-methoxyphenyl)
propan-1-one (3i) (Chauan-Ji and Chen-Jiang, 2010) 1H
NMR (400 MHz, CDCl3) d: 7.97 (s, 1H), 7. 91 (d, J =
8.4 Hz, 2H), 7.39 (d, J = 8 Hz, 2H), 7.34–7.27 (m, 3H),
7.15(t, J = 7.2 Hz, 1H), 7.03–6.90 (m, 6H), 5.04 (t, J =
7.6 Hz, 1H), 3.85 (s, 3H), 3.74 (dd, J = 6.4, 16.8 Hz, 1H),
3.63 (dd, J = 8, 16.4 Hz, 1H). 13C NMR (400 MHz,
CDCl3) d: 197.1 (CO–C1), 164.2 (C4–Ar1), 149.5 (C4–Ar3),
1-(4-Bromophenyl)-3-(4-fluorophenyl)-3-(1H-indol-3-yl)
propan-1-one (3g) IR (KBr): m 3409, 2923, 1681, 1218,
1
1072 cm-1, H NMR (400 MHz, CDCl3) d: 7.98 (s, 1H),
123

Med Chem Res
139.0 (C3,5–Ar1), 138.4 (C1–Ar1), 137.3 (C9–Ind), 135.7
(OCH3, CH2–C2). MS: m/z = 438.0 (M?23). Elemental
analysis calcd for C26H25NO4 = C, 75.16, H, 6.06, N,
3.37 % Found C, 75.21, H, 6.16, N, 3.30 %.
(C1–Ar3), 130.1 (C3,5–Ar3) 128.1 (C2,6–Ar3), 127.2 (C2,6
–
Ar1), 122.5, 122.3, 119.4, 119.3, 118.9, 110.4 (C8,2,5,6,4,3,7–Ind),
56.3 (OCH3), 45.7 (CH–C3), 37.8 (CH2–C2). MS: m/z = 374.0
(M? 1). Elemental analysis calcd for C24H20FNO2 = C,
77.19, H, 5.40, N, 3.75 % Found C, 77.23, H, 5.36, N, 3.70 %.
Cytotoxic study
Propidium iodide (PI) staining assay (Zakiah et al., 2012)
3-(3,4-Dimethoxyphenyl)-3-(1H-indol-3-yl)-1-phenylpro-
pan-1-one (3j) IR (KBr):
m
3379, 2932, 1681,
PI was used to stain the nuclear changes of living and apoptotic
cells. Briefly, ACHN, Panc1, Calu1, H460 and HCT116 cancer
cell lines along with normal MCF10A cells (2 9 106 cells/
well) were incubated for 24 h in 5 % CO2 at 37 °C with dif-
ferent concentrations of the synthesized compounds 3a–
l. Gemcitabine and Flavopyridol were used as positive controls.
The cells were further incubated for another 48 h, harvested,
homogenised in 200 lL of 1 % formaldehyde and again
incubated for 15 min. The cells were washed twice with cold
PBS (Phosphate Buffered Saline), and then 1 mL of 10 lg/mL
PI was added into each well and incubated at 37 °C for 5 min in
dark to allow nuclear penetration. After being washed with cold
PBS, the cells were detected by blue filter (515 nm) fluorescent
microscope (Olympus Corp., Shibuya-ku, Tokyo, Japan) at
4009 magnification. The activity of derived compounds of
inhibitory constants was predicted based on standard deviation.
1257 cm-1, H NMR (400 MHz, CDCl3) d: 7.98 (s, 1H),
7. 85 (d, J = 6.4 Hz, 2H), 7.44 (d, J = 8 Hz, 1H), 7.40–
7.38 (m, 2H), 7.33 (d, J = 8.4 Hz, 1H), 7.18–7.14 (m, 1H),
7.05–7.01 (m, 1H), 6.9 (s, 1H), 6.86–6.84 (m, 2H), 6.75 (d,
J = 8.8 Hz, 1H), 4.98 (t, J = 7.2 Hz, 1H), 3.81 (s, 3H),
3.78 (s, 3H), 3.72 (dd, J = 6.4, 16.4 Hz, 1H), 3.65 (dd,
J = 8.4, 17.6 Hz, 1H). 13C NMR (400 MHz, CDCl3) d:
198.0 (CO–C1), 149.2 (C4–Ar3), 147.9 (C3–Ar3), 139.9
1
(C1–Ar1), 136.9 (C4–Ar1), 135.9 (C1–Ar3), 129.9 (C3,5
–
Ar1), 126.9 (C5–Ar3), 122.6 (C2–Ind), 121.7 (C2–Ar3), 119.9,
119.9, 119.8, 111.4 (C6,4,3,7–Ind), 56.2 (2OCH3), 45.6 (CH–
C3), 38.4 (CH2–C2). MS: m/z = 384.0 (M-1). Elemental
analysis calcd for C25H23NO3 = C, 77.90, H, 6.01, N,
3.63 % Found C, 77.93, H, 6.09, N, 3.59 %.
1-(4-Chlorophenyl)-3-(2,6-difluorophenyl)-3-(1H-indol-3-yl)
propan-1-one (3k) IR (KBr): m 3417, 2962, 1681, 1265,
1
1087 cm-1, H NMR (400 MHz, CDCl3) d: 8.03 (s, 1H),
Conclusion
7. 91–7. 89 (m, 2H), 7.68 (d, J = 8 Hz, 2H), 7.42–7.39 (m,
2H), 7.33 (d, 8 Hz, 1H), 7.19–7.15 (m, 2H), 7.12–7.07 (m,
2H), 6.82 (t, J = 8.4 Hz, 1H), 5.46 (t, J = 7.6 Hz, 1H), 4.06
(dd, J = 8.8, 17.2 Hz, 1H), 3.85 (dd, J = 6, 17.6 Hz, 1H).
13C NMR (400 MHz, CDCl3) d: 197.4 (CO–C1), 163.0 (C2–
Ar3), 160.6 (C6–Ar3), 160.5 (C4–Ar1), 139.9 (C1–Ar3), 136.
In conclusion, we demonstrated an efficient and simple
procedure for the Michael addition of indole to a,b-
unsaturated ketones catalysed by indium(III) sulphate. The
resultant compounds were tested to identify the cytotoxic
effect on cancer cell lines. The bioactivity of cell lines
compared with standard shows 3e and 3l have significant
effect with all tested cancer cell lines with IC50 values
ranging from 1.4 to 2.7 lM % SAR activation value of
0.46 and 2.4–3.4 lM % SAR activation of 0.407, respec-
tively. The standard compounds Gemcitabine and Flavo-
piridol show % SAR activation of 0.434 and 0.53.
4 (C9–Ind), 135.5 (C1–Ar1), 129.9 (C3,5–Ar1), 128.3 (C3,5
–
Ar3), 128.3 (C4–Ar3), 122.6, 122.0, 120.1, 119.2, 117.3, 111.
5 (C5,2,6,4,3,7–Ind), 42.7 (CH–C3), 37.5 (CH2–C2). MS:
m/z = 418.8 (M?23). Elemental analysis calcd for
C23H16ClF2NO = C, 69.79, H, 4.07, N, 3.54 % Found C,
69.81, H, 4.11, N, 3.50 %.
Acknowledgments The authors thank Department of Post Graduate
Studies and Research in Chemistry, Kuvempu University for providing
laboratory facilities and Prabhu D Mishra, Senior Group Leader, Nat-
ural Products Chemistry, Piramal Healthcare Limited Goregaon
(E) Mumbai for screening the compounds for in vitro cytotoxic activity.
3-(2,4-Dimethoxyphenyl)-3-(1H-indol-3-yl)-1-(4-methoxy-
phenyl)propan-1-one (3l) IR (KBr): m 3332, 2931, 1674,
1242 cm-1 1H NMR (400 MHz, CDCl3): d = 7.91 (s,
,
1H), 7.92 (d, J = 8.8 Hz, 2H), 7.45 (d, J = 8.0 Hz, 1H),
7.32 (d, J = 8.4 Hz, 1H), 7.15 (t, J = 7.2 Hz, 1H), 7.02 (t,
J = 7.2 Hz, 1H), 6.9 (s, 1H), 6.91–6.85 (m, 4H), 6.74 (d,
J = 8.8 Hz, 1H), 5.00 (t, J = 7.6 Hz, 1H), 3.85 (s, 3H),
3.81 (s, 3H), 3.76 (s, 3H), 3.71–3.66 (m, 2H). 13C NMR
(400 MHz, CDCl3) d = 197.5 (CO–C1), 146.6 (C2,4–Ar3),
137.1 (C1–Ar3), 136.0 (C9–Ind), 134.7 (C3,5–Ar3), 132.3
References
Abdel-Rahman F (2010) Synthesis of some new indole derivatives
containing pyrazoles with potential antitumor activity. Arkivoc
Xi:177–187
Arrigo S, Rosaria V, Maria RA (2009) Asymmetric Friedel-Crafts
alkylation of indole with chalones catalyzed by chiral phosphoric
acids. Molecules 14:3030–3036
(C6–Ar3), 130.1 (C1–Ar1), 130.0 (C2,6–Ar1), 129.9 (C3,5
–
Ar1), 127.3, 122.8, 121.8, 120.1, 119.8, 118.8, 111.5
(C5,2,6,4,3,7–Ind), 45.2 (2OCH3), 40.3 (CH–C3), 38.2
123

Med Chem Res
Bei-Yao L, Miao Z, Xin-Min Y, Yan-Qing P (2010) Conjugate
addition of indole to a,b-unsaturated ketones catalyzed by lewis
acid immobilized on a biorenewable support. J Chin Chem Soc
57:1243–1247
Bimal KB, Migue F, Claeissa A (2005) Iodine-catalyzed highly
efficient Michael reaction of indoles under solvent-free condi-
tion. Tetrahedron 46:2479–2482
Magdy AHZ, Atef MI (2009) Synthesis and cellular cytotoxicities of
new N-substituted indole-3-carbaldehyde and their indolylchal-
cones. J Chem Sci 121(4):455–462
Magdy AHZ, Hanan FS, Yasmin GA, Gamal-Eldeen Amira M (2010)
Efficient microwave irradiation enhanced stereoselective syn-
thesis and antitumor activity of indolylchalcones and their
pyrazoline analogs. J Chem Sci 122(4):587–595
Bindu PJ, Mahadevan KM, Ravikumar Naik TR (2012a) Sm(III)ni-
trate-catalyzed one-pot synthesis of furano[3,2c]-1,2,3,4-tetra-
hydroquinolines and DNA photocleavage studies. J Mol Struct
1020:142–147
Bindu PJ, Mahadevan KM, Satyanarayan ND, Ravikumar Naik TR
(2012b) Synthesis and DNA cleavage studies of novel quinoline
oxime esters. Bioorg Med Chem Lett 22:898–900
Marco B, Pier GC, Massimo G, Paolo M, Simona S, Achille UR
(2002) Sequential one-pot InBr 3-catalyzed 1,4-then 1,3-nucle-
ophilic addition to enones. J Org Chem 67:3700–3704
Michael WR, Jean HO, Ashley MY, Paul WE, William AM (2012)
Synthesis and evaluation of indole-based chalcones as inducers
of methuosis, a novel type of nonapoptotic cell death. J Med
Chem 55(5):1940–1956
Brindaban CR, Suvendu SD, Sampak S (2005) Indium(III) chloride-
catalyzed Michael addition of thioles to chalcones: a remarkable
solvent effect. Arkivoc iii:44–50
Buyukbingol E, Suzen S, Klopman G (1994) Studies on the synthesis
and structure–activity relationships of 5-(30-indolyl)-2-thiohyd-
antoin derivatives as aldose reductase enzyme inhibitors. Il
Farmaco 49:443–447
Chauan-Ji Y, Chen-Jiang L (2010) Synthesis of b-indolylketones
catalyzed by bronsted acidic ionic liquid [HSO3-bpy][HSO4].
Chem J Chin Univ 31(6):1158–1161
Chen I, Safe S, Bjeldanes L (1996) Indole-3-carbinol and dii-
ndolylmethane as aryl hydrocarbon (Ah) receptor agonists and
antagonists in T47D human breast cancer cells. Biochem
Pharmacol 51:1069–1076
Dalip K, Maruthi KN, Kanako A, Eriko K, Hiroshi H, Takeo I (2010)
Synthesis and biological evaluation of indolyl chalcones as
antitumor agents. Bioorg Med Chem Lett 20:3916–3919
Ekhlass N (2010) Synthesis, (in vitro) antitumor and antimicrobial
activity of some pyrazoline, pyridine, and pyrimidine derivatives
linked to indole moiety. J Am Sci 6(8):338–347
Jianwei X, Xinhai Z, Manna H, Fei M, Man W, Yiqian W (2010)
Sc(OTf)3: a highly efficient and renewable catalyst for Michael
addition of indoles to nitroolefins in water. Synth Commun
40:3259–3267
Rodney A, Fernandes (2008) A short synthesis of (?)-(S)-kurasoin B.
Tetrahedron Asymmetry 19:15–18
Shum-ichi I, Uichiro K, Tadashi A, Katsushige G, Hiromitsu S,
Masaji K, Junji K, Kimihito S, Etsuko N, Masami O, Soichiro S
(1999) Patent written in English, p. 48, Cont-in-part of US Ser.
No. 641, 699
Suzen S, Buyukbingol E (1998) Evaluation of anti-HIV activity of
5-(2-phenyl-30- Indolyl)-2-thiohydantoin. Il Farmaco 53:525–527
Suzen S, Buyukbingol E (2000) Anti-cancer activity studies of
indolalthiohydantoin (PIT) on certain cancer cell lines. Farmaco
55:246–248
Vishal S, Raman K, Tilak R, Vivek KG, Nitasha S, Ajit KS, Deepak
S, Surinderjit SB, Gurpinder S, Mohan PSI (2012) Synthesis and
cytotoxic evaluation of substituted 3-(30-indolyl-/30-pyridyl)-
isoxazolidines and bis-indoles. Acta pharmaceutica Sinica B
2(1):32–41
Xiang J, Haibo T, Yu Y (2011) Facile and efficient Michael addition
of indole to nitroolefins catalyzed by Zn(OAc)2 2H2O. Synth
Commun 41:372–379
Zakiah J, Nur NNN, Norwahidah AK, Wan ZWN (2012) Antipro-
liferative activity and apoptosis induction by gelam honey on
liver cancer cell line. IJAST 2(4):135–141
Zhi-Liang S, Shun-Jun J, Teck-Peng L (2008) Indium(III) iodide-
mediated Strecker reaction in water: an efficient and environ-
mentally friendly approach for the synthesis of a-aminonitrile
via a three-component condensation. Tetrahedron 64:8159–8163
Kameshwara RV, Bhupender SC, Amir NS, Rakesh T, Keykavous P,
Anil K (2011) 3-Substituted indoles: one-pot synthesis and
evaluation of anticancer and Src kinase inhibitory activities.
Bioorg Med Chem Lett 21:3511–3514
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