Triphenylethylene analogues: Design, synthesis and evaluation of antitumor activity and topoisomerase inhibitors

Article abstract of DOI:10.1016/j.ejmech.2020.112775

To structurally relate anticancer drug tamoxifen used in the treatment of breast cancer, a sequence of compounds is designed and synthesized as potential drug candidates. McMurry coupling reaction is used as the key synthetic step in the preparation of these analogues and the ratios of E/Z-isomers are determined on the basis of NMR and HPLC experiments. The new compounds are found to be cytotoxic in the micromolar range with 60 human tumor cell lines at one dose and five dose concentration levels. Detailed studies on the most active compounds 11–13 show these compounds are capable to inhibit the growth of cancer cells. Finally, with the aim to correlate the antiproliferative activity with an intracellular target(s), the effect on relaxation activity of DNA topoisomerase-II is assayed. The relevance of interaction of most active compounds with topoisomerase-II is demonstrated which is also supported by docking studies.

Full text of DOI:10.1016/j.ejmech.2020.112775

European Journal of Medicinal Chemistry 208 (2020) 112775
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Research paper
Triphenylethylene analogues: Design, synthesis and evaluation of
antitumor activity and topoisomerase inhibitors
Sudesh Rani, Kamaldeep Paul*
School of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, 147001, India
a r t i c l e i n f o
a b s t r a c t
Article history:
To structurally relate anticancer drug tamoxifen used in the treatment of breast cancer, a sequence of
compounds is designed and synthesized as potential drug candidates. McMurry coupling reaction is used
as the key synthetic step in the preparation of these analogues and the ratios of E/Z-isomers are
determined on the basis of NMR and HPLC experiments. The new compounds are found to be cytotoxic in
the micromolar range with 60 human tumor cell lines at one dose and five dose concentration levels.
Detailed studies on the most active compounds 11e13 show these compounds are capable to inhibit the
growth of cancer cells. Finally, with the aim to correlate the antiproliferative activity with an intracellular
target(s), the effect on relaxation activity of DNA topoisomerase-II is assayed. The relevance of interaction
of most active compounds with topoisomerase-II is demonstrated which is also supported by docking
studies.
Received 9 April 2020
Received in revised form
8 August 2020
Accepted 19 August 2020
Available online 30 August 2020
Keywords:
Tamoxifen derivatives
McMurry reaction
Antitumor activity
Topoisomerase-II
MTT assay
© 2020 Elsevier Masson SAS. All rights reserved.
1. Introduction
antioxidant [10,11], antifungal [9], antiangiogenesis [12] and anti-
viral [9] properties. Moreover, it reduces the risk of coronary artery
The incidence of cancer continues to increase and remains the
second leading cause of mortality through worldwide [1]. Among
women, breast cancer is the one of the most common causes of
death [2]. According to American Cancer Society Statistics esti-
mated in 2019, over 1,762,450 cases of cancer were diagnosed in
United States alone and that over 606,880 people died from this
disease [3]. In recent years, researchers have made considerable
progress in the field of drug discovery but still drug resistance in
cancer treatment remains a frontline intervention [4]. In pharma-
ceuticals, a pioneering drug tamoxifen (I, Fig. 1) has attracted the
attention of researchers over many years [5]. Tamoxifen (I, Fig. 1) is
a triphenylethylene substituted selective estrogen receptor modu-
lator (SERM) which is employed as a chemotherapeutic agent for
breast cancer [6]. It is the first line chemopreventive which is
effective at every stage of breast cancer in premenopausal and
postmenopausal women [7]. These days, tamoxifen (I) (Z-isomer)
has been sold as brand name Nolvadex and considered as one of the
best selling medicine for breast cancer [8]. In addition to breast
cancer, tamoxifen (I) (triphenylethylene derivative) also exhibited
immense pharmacological properties such as antibacterial [9],
disease and bone fractures at some sites [13]. In recent years,
tamoxifen analogues have made a significant impact on the phar-
macotherapy of estrogen receptor (ER) positive cancer cell lines.
Despite its many advantages, the most challenging issue is ac-
quired resistance which often emerges with long term adminis-
tration of tamoxifen (I, Fig. 1) in the victim [14]. Tamoxifen (I) acts
as partial agonistic, thus, increasing the risk of endometrium cancer
and venous thromboembolism [15]. It is also associated with
numerous side effects such as menstrual abnormalities, vaginal
dryness, hot flashes and hepatocytotoxicity [16e18].
Primarily, tamoxifen (I) ceases the tumor growth either by
blocking estrogen receptor or inhibiting estrogen receptor medi-
ated signaling pathways which prevents the interaction of tran-
scription factor-ER [19]. As tamoxifen (I) has many sites of action,
several non-ER mediated mechanisms of cytotoxcity have been
documented such as PKC inhibition [20], calmodulin inhibition [21]
and by suppressing formation of L-glutamate [22] etc. Besides
these, tamoxifen (I) targets cellular DNA through intercalation [23]
or by inhibiting the enzymes which promote DNA replication such
as topoisomerase [24,25]. It is a cationic drug and inhibits both b-
oxidation and respiration in hepatic mitochondrial cells [25]. This
causes cell cycle arrest and leads to programmed cell death called
apoptosis.
* Corresponding author.
E-mail address: kpaul@thapar.edu (K. Paul).
Through structural-activity relationship studies, it has been
https://doi.org/10.1016/j.ejmech.2020.112775
0223-5234/© 2020 Elsevier Masson SAS. All rights reserved.

2
S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
Fig. 1. Structure of drug tamoxifen (I), toremifene (II), ospemifene (III); and tamoxifen derivative in clinical trial droloxifene (IV); and bioactive lead (V).
observed that the triarylethylene core (as in tamoxifen (I)) forms
the backbone which mimics the effect of natural estrogen. It was
observed that this core acts as an estrogen agonist and side-chain
attached to the core is responsible for its antagonistic (full/par-
tial) behavior [26]. Over the past years, some of the triphenyl-
ethylene analogues such as toremifene (II), ospemifene (III) and
droloxifene (IV) (Fig. 1) have been studied extensively in clinical
trials [27]. The effect of varying O-substituted aminoalkyl side chain
has been demonstrated in the case of tamoxifen (I) [28], ospemi-
fene (III).
[29] and bioactive lead (V) [30]. Recently, endoxifen, one of the
metabolites of tamoxifen has been evaluated in phase I clinical
trials for bipolar disorder [31]. Additionally, it has also been re-
ported that substituting one of N-methyl group of tamoxifen side
chain by a N-(2,2,2-trifluoroethyl) group loses its potency to inhibit
MCF-7 cells [32]. This profound effect shows that the decrease in
basicity of side chain reduces its potency towards cancer cell lines.
Altogether, to develop structure-activity relationships towards the
novel anticancer active triarylethylenes, variation in side-chain
attached to its core has gained substantial attention in literature
(Fig. 2).
In our present work, we have synthesized a new series of tri-
phenylethylene analogues via McMurry coupling reaction with
variations in amine side chain and characterized by various spec-
troscopic techniques. We described the synthesis of fifteen novel
compounds and evaluated their anti-proliferative effect on a panel
of 60 human cancer cell lines. It has been revealed that by the
replacement of ethyl group with methyl group and introduction of
amino-substituted isopropanol chain in tamoxifen (I) is considered
as significant structural changes to enhance the anticancer activity.
To study the molecular targets for cytotoxcity, the effect on
topoisomerase-II relaxation is reported for the most cytotoxic de-
rivatives. Furthermore, colorimetric analysis was also performed to
investigate the toxicity towards normal cell lines. Docking studies
also suggested a plausible explanation of the biological experi-
mental evidences.
2. Results and discussion
2.1. Chemistry
To synthesize triphenylethylene scaffolds, a chemical approach
was depicted including McMurry coupling and nucleophilic sub-
stitution reaction as shown in Scheme 1. Cross-coupled product 4-
(1,2-diphenylprop-1-en-yl)phenol (3) was easily prepared by the
reaction of equimolar amount of 4-hydroxy benzophenone (1) with
acetophenone (2) via McMurry reaction [33], in a very good yield
(80%). Subsequently, the desired intermediate 4 in 3.4:1 ratio of E-
and Z-isomers was furnished in good yield (65%) by the treatment
of compound 3 with epichlorohydrin in the presence of potassium
carbonate in acetonitrile. Finally, epoxide 4 was treated with
various primary and secondary amines in acetonitrile at reflux
temperature. The epoxy ring was opened up to afford corre-
sponding derivatives 5e19 in quantitative yield 65e85% with
varying ratio of E- and Z-isomers (Scheme 1). The statistical mixture
of E- and Z-stereoisomers of triphenylethylene derivatives was
obtained and attempts were made to isolate the E- and Z-isomers
but these were unsuccessful due to same Rf value in different sol-
vent systems. So, without any isolation of E- and Z-stereoisomers,
the synthesized analogues were characterized by 1H NMR, 13C NMR,
and mass spectrometry (Schemes S1eS33). Further, the E/Z ratio of
triphenylethylene derivatives was confirmed by 1H NMR from the
integral of respective protons [34] as well as HPLC methodology
[35]. Moreover, the stereochemical assignments of the E- and Z-
isomers were determined on the basis of chemical shifts in 1H NMR
as well as 2D-NOESY and COSY experiments (Figs. S34 and S35)
Fig. 2. Design of novel triphenylethylene analogs.

S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
3
Scheme 1. Synthesis of triphenylethylene analogues with variation of amines (5e19).
where methyl group (deshielded protons at
isomer showed NOE with one of the aromatic ring and that NOE is
absent in case of other isomer (Z-isomer, at 2.10 ppm). The side
d
2.14 ppm) of the E-
were also compared with known drug tamoxifen.
Most of the synthesized triphenylethylene analogues show an
interesting antiproliferative activity with negative % growth inhi-
bition with a higher cytotoxic activity towards most of the cancer
cell lines. An opposite behavior, as expected, was found for
tamoxifen, which shows cytotoxicity towards few cancer cell lines.
Moreover, the comparison between the obtained results and the
chemical structures of the new derivatives 5e19, allowed some
interesting structure-activity relationships to be discovered. The
analogous with secondary amine substituents piperidine (5), N-
ethylpiperazine (8) and N-benzylpiperazine (10) and primary
amine substituents allyl amine (15) and 2-aminopyrazine (19)
show a scarce antiproliferative activity and were considered to be
least effective in the series. Increase in lipophilicity in case of
analogous of triphenylethylene with substituents morpholine (6),
N-methylpiperazine (7), N-phenylpiperazine (9), butyl amine (16),
benzyl amine (17) and 4-flouroaniline (18) increased the anti-
proliferative activity to some extent. Interestingly, derivatives
bearing primary amines 4-(2-aminoethyl)morpholine (11), cyclo-
hexylamine (12), N,N-diethylethylenediamine (13) and N,N-dime-
thylethylenediamine (14) render the compounds more active,
suggesting that hydrophilicity and/or hydrogen bond donor played
an important role in the cytotoxic effect (Tables S1eS3).
d
chain at aromatic ring also showed similar behavior. This rela-
tionship is also found to be true for tamoxifen as all the protons of
E-tamoxifen resonate at down-field as compared to Z-tamoxifen
[36,37]. The E/Z ratio of derivatives was confirmed by reverse phase
HPLC methodology by opening of the epoxy ring with piperidine (in
case of compound 5). Chromatogram of compound 5 spiked with E-
and Z-isomers is shown in Fig. S36. The retention times of E- and Z-
triphenylethylene have been found to be 10.14 and 12.41 min,
respectively. Thus, the 1H NMR spectrum of compound 5 contained
CH3 singlet, centered at
d 2.14 ppm and d 2.10 ppm was assigned E
configuration (retention time of 10.14) and Z configuration (reten-
tion time of 12.14), respectively. It has been revealed that the ratio
of E/Z-isomers determined from 1H NMR is corroborated with HPLC
as both have same ratio of isomers i.e. 2.2:1. The E/Z ratios of other
derivatives were also determined in the same methodologies.
2.2. In vitro antiproliferative activity
The E/Z derivatives of triphenylethylene series 5e19 were cho-
sen by the National Cancer Institute, USA on account of computer
modeling techniques for anticancer activity [38]. These compounds
were evaluated in vitro for antiproliferative assay against a panel of
60-human cancer cell lines at a single dose of 10 mM concentration,
and the percentages of growth inhibition (% GI) over these cell lines
were determined (Tables 1 and 2). Further the obtained results
Preliminary in vitro activity revealed that compound 6 inhibited
the growth of leukemia cancer cell line K-562 and colon cancer cell
line HT29 with growth inhibition of 80.30% and 86.88%, respec-
tively. Compound 7 displayed selectivity towards leukemia cancer
cell lines (K-562; GI ¼ 95.76%, SR; GI ¼ 96.19%) and colon cancer cell

4
S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
Table 1
Percentage growth inhibition (GI%) of in vitro subpanel tumor cell lines at 10 mM concentration of compounds 5e12.
Panel
Cell line
5
6
7
8
9
10
11
12
Leukemia
CCRF-CEM
8.64
19.56
24.80
-
29.97
4.15
43.49
-33.44
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
4.77
31.06
5.24
4.61
24.68
-
4.16
-
6.16
0.76
-
-
39.28
80.30
38.51
24.96
52.84
12.84
3.36
9.90
19.77
3.44
-
4.48
7.41
26.73
30.64
-
21.39
95.76
38.42
25.00
96.19
27.94
10.98
18.15
35.35
-
5.03
9.54
29.03
11.04
37.46
9.11
-
23.27
91.77
28.81
17.74
2.85
15.64
-
15.25
35.29
17.63
28.55
3.59
61.61
-
7.12
-
-
-
2.33
-
-
-
38.95 10.84
70.99
97.60
59.01
79.80
99.31
29.23
17.17
25.13
40.88
3.88
16.77
27.32
82.40
55.45
-57.06
98.44
43.74
40.97
42.42
39.72
21.29
21.20
-
6.25
-
6.98
-
-
-
-
-41.90
-43.71
-11.36
-63.65
-32.61
-69.72
-89.52
22.74
-80.19
-90.41
-92.05
-54.71
Lung
A549
EKVX
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
SF-295
SF-539
SNB-19
2.85
26.06
12.46
25.05
6.94
-
-
-
-
-
-
-
-
11.59 19.71
-
-
-
3.68
-
-
-
-
4.96
-
-
-
9.85
29.64
-
3.87
-
-
-
8.61
3.59
-
-
2.68
-
-
-
1.04
-
-
-
16.99
7.80
-
-
-
-
Colon
-64.50 -61.83
-59.62 -93.32
-
25.67
38.82
65.87
31.35
26.69
-
-
-
-
-
-
-
7.30
53.65
46.16
86.88
36.37
11.43
-
95.53
96.81
45.69
50.95
28.83
27.18
8.80
34.22
67.39
81.30
-71.70 -88.65
7.31 7.51
-63.83 -93.78
5.09
-86.2
70.97
-88.15
-42.26
-82.85
-85.96
-95.44
-97.16
-56.53
-93.70
-58.37
-99.24
-
-
-
CNS
25.75
-
8.67
-
-
-
5.50
-
-
-
-
-
-
-
3.39
-
-
-
-
-
-
-
SNB-75
U251
LOX IMVI
MALME-3M
M14
8.61
19.91
12.15
24.75
-45.08
9.29
1.12
10.04
12.88
6.64
3.00
3.82
9.60
10.69
12.81
11.48
6.78
24.69
24.23
7.89
19.99
10.69
13.34
10.39
-
-
-
-
-
Melanoma
-
MDA-MB-435
SK-MEL-2
SKMEL-28
SK-MEL-5
UAAC-257
UAAC-62
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
NCI-RES
SK-OV 3
786-0
A-498
ACHN
CAKI-1
SN12C
TK-10
UO-31
PC-3
DU-145
8.99
-
-
-60.26
-96.36
-96.13
17.42
9.87
16.76
37.33
36.65
22.11
29.77
24.76
21.84
19.81
4.57
17.79
8.47
12.30
9.02
15.31
25.16
2.30
11.59
18.18
-
-
-
-
-
-
-
-27.51 -62.76
37.33
36.65
22.11
29.77
24.76
21.84
19.81
4.57
-72.18
-93.28
-88.29
-86.38
-91.75
Ovarian
Renal
-
1.77
-
-
-
-
-
13.49
-
10.98
2.91
-
17.37
3.23
-
14.84
-
3.01
1.40
-
-
5.97
-
-
-
-
-
-
-
-37.30
-74.71
-31.44
-
8.68
32.87
8.44
-
17.63
-
2.44
13.96
1.00
11.20
10.98
5.31
22.40
16.19
11.04
30.20
-
20.05
18.56
32.14
23.93
26.48
30.83
34.55
32.25
55.39
70.63
29.51
-
31.68
-100.0
-95.99
-91.03
-66.91
-99.83
-79.44
-89.14
-89.78
-90.39
-58.46
-
1.16
2.30
4.23
19.87
11.63
5.68
26.33
28.17
1.88
15.80
-
9.19
14.26 17.75
-
-
-
-
-
-
-
-
-
-
-
-
22.36
2.44
-
-
-
-
63.15
22.44
8.36
Prostate
Breast
30.12
MCF7
-
-
-
52.99
10.24
9.59
MDA-MB-231
HS 578T
BT-549
T-47D
MDA-MB-468
6.96
-
10.78
1.28
16.16
-
5.73
6.69
39.68
14.87
5.70
10.74
45.18
26.24
-
-
10.65
46.86
-60.46
-79.45
6.56
- indicated inactive, bold - %GI ≥ 50%, red bold – cytotoxic

S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
5
Table 2
Percentage growth inhibition (GI%) of in vitro subpanel tumor cell lines at 10
m
M concentration of compounds 13e19.
Panel
Cell Lines
13
14
15
16
17
18
19
TAM
Leukemia
CCRF-CEM
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
A549
EKVX
HOP-62
HOP-92
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
SF-268
-
-
31.00
37.01
88.82
31.72
-17.72
23.56
11.03
-
4.26
5.49
3.96
12.29
-45.45
14.22
-26.15
-37.79
91.66
82.10
89.24
60.24
85.31
1.48
-
6.47
6.20
14.85
19.11
-
14.57
13.99
17.19
9.26
28.56
18.51
13.99
4.28
5.91
20.68
-
32.91
69.53
29.60
37.40
37.41
30.62
24.93
18.78
-
-
-
-18.04
-49.05
-22.96
-18.48
-34.85
-5.03
-32.08
82.31
-41.83
-9.64
69.22
-13.70
89.95
51.97
61.26
-1.12
28.60
19.27
22.52
50.20
-
65.4
60.4
-
66.7
-28.3
-18.9
50.2
40.0
56.9
2.90
-
-
4.07
1.77
1.36
-
-
-
-
-
17.73
-
-
-
-
-
-
-
Lung
-
-
17.14
65.34
-1.25
-
7.50
39.7
34.0
97.6
53.4
-89.0
83.7
73.8
92.4
-11.2
75.0
95.1
43.3
59.8
-
47.4
60.1
95.2
-43.9
-67.5
-75.0
62.2
31.5
88.7
-95.2
-64.3
-
9.83
18.43
-
7.71
37.75
-
7.30
25.04
25.66
12.05
23.17
16.62
-
14.06
-
-
23.02
-
-
7.02
3.04
-
6.05
-
-
-
17.64
78.33
27.80
-47.32
56.59
21.93
69.64
90.25
29.56
28.94
-
25.42
25.29
16.34
12.04
72.76
72.53
37.77
17.64
92.57
2.14
39.73
24.63
25.43
-
23.75
19.81
27.02
12.95
22.12
-
-81.04
-24.03
-50.71
-85.53
33.21
-24.27
-28.60
-92.32
-69.07
-
-83.19
-83.56
91.33
-87.43
-50.84
-83.53
-88.83
9.43
87.96
-41.46
-87.09
-96.96
-55.80
-82.75
-32.02
-70.78
-52.37
84.32
91.29
11.84
-
-
28.79
-
-
-
-
-
-
6.54
1.10
-
-
Colon
-
15.85
5.69
7.92
6.54
3.38
-
CNS
SF-295
SF-539
SNB-19
SNB-75
11.27
5.35
19.29
27.58
-81.49
15.78
23.78
-
5.41
-
-
4.09
-
3.70
-
13.73
7.44
8.93
3.48
-
-
-
-
-
7.77
20.39
4.71
13.40
12.32
11.49
8.49
5.85
-
U251
Melanoma
LOX IMVI
MALME-3M
M14
-
12.06
-
-
-
-
-
-
-
25.70
12.24
-
17.15
-
-
-
4.11
-
-
-
-
-
-
-
MDA-MB-435
SK-MEL-2
SKMEL-28
SK-MEL-5
UAAC-257
UAAC-62
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
NCI-RES
SK-OV 3
786-0
A-498
ACHN
CAKI-1
SN12C
TK-10
UO-31
PC-3
DU-145
MCF7
MDA-MB-231
HS 578T
BT-549
T-47D
-
2.72
6.69
-
34.62
23.22
22.21
-
46.08
17.04
-
18.77
9.09
2.91
20.97
23.63
-
43.55
26.21
24.08
62.21
-
6.81
-
11.37
86.59
-
-
6.41
-
2.29
-
11.35
3.55
9.31
17.39
-
36.50
16.24
7.40
20.62
2.67
6.12
8.36
-
-
Ovarian
Renal
-
-
58.8
47.1
53.7
-
-
4.33
-
-
-
1.87
4.04
-
4.39
-
2.21
8.86
4.04
9.09
39.5
7.12
-
9.16
59.36
-52.71
9.79
56.8
33.2
-41.0
35.9
39.4
70.9
52.3
48.1
59.7
65.6
34.6
-10.3
54.8
39.5
30.2
-
-
7.44
-
10.58
72.10
21.12
-
57.23
26.44
3.45
13.42
28.98
-
-
20.67
3.74
20.07
-
17.09
20.65
24.18
12.96
11.56
30.46
24.19
22.09
27.12
31.70
22.55
6.37
-
-76.21
-33.48
-56.47
68.67
-28.94
-83.59
-22.53
94.58
-46.00
-43.62
-47.83
6.02
14.80
35.13
12.95
-
42.40
19.26
5.95
-
26.94
20.62
-
18.87
8.72
-
30.24
6.19
-
Prostate
Breast
3.41
-
-
-
-
-
-
-
-
11.66
-
-
18.42
11.49
-
25.68
8.97
-3.36
-65.15
MDA-MB-468
42.18
-
-13.3
- indicated inactive, bold - %GI ≥ 50%, red bold – cytotoxic

6
S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
line (HT29; GI ¼ 91.77%), melanoma cancer cell line (MDA-MB-435;
GI ¼ 61.61%) while compound 16 showed cytostatic activity to-
wards leukemia cancer cell line K-562, and colon cancer cell lines
HCC-2998, HCT-116, HCT-15, HT29 and KM12, and cytotoxic activity
towards RPMI-8226, NCIeH322 M, NCIeH522, COLO 205 and
U251 cell lines. As it is clear from the data given in tables, due to an
increase in basicity, compounds 11e13 exhibited excellent cyto-
static activity as well as cytotoxicity towards most of the cancer cell
lines and therefore selected to test their anticancer activity at 5-
dose concentration levels. Moreover, for most of the cancer cell
lines, compounds 12 and 13 had more cytotoxicity than tamoxifen,
indicating these compounds exhibited high selectivity and activity
than tamoxifen and may also act via non-estrogen mechanism.
Compounds 11e13 were selected by the NCI for further testing
for in vitro antitumor activity against 60 human tumor cell lines.
The GI50, total growth inhibition (TGI) and half maximal lethal
concentration (LC50) were measured in micromolar range for each
cell line. For K562 human leukemia cancer cell line, compounds 12
Fig. 3. Cytotoxic effect of compounds 11, 12 and 13 to human normal cell line
(Hek293).
2.4. DNA topoisomerase-IIa mediated relaxation activity
and 13 had GI50 values of 0.35 mM and 0.52 mM, respectively; values
To account for possible mechanism of cytotoxicity, the effect of
the most active compounds 11, 12 and 13 on relaxation activity of
represent an activity higher than that for tamoxifen (TAM). Com-
pound 13 also showed very good activity towards colon cancer cell
line HT29 and melanoma cancer cell line LOXIMVI with GI50 values
plasmid DNA catalyzed TOPO-IIa was analyzed. As topoisomerase is
a class of nucleoenzyme, the enzymatic action of topoisomerase-II
a
of 0.56 mM and 0.43 mM, respectively. The MG MID GI50 values of
converts the supercoiled DNA into relaxed form. The inhibition of
topoisomerase-II action impairs DNA replication, thus prevents the
cell growth [39]. Supercoiled pHOT1 plasmid DNA was incubated
these three compounds on the 60 tumor cell lines are shown in
comparison with known drug TAM as positive control in Table 3.
Compound 11 showed comparable activity as tamoxifen while
compound 12 having cyclohexylamine in side-chain with GI50 value
with TOPO-IIa and 50 mL of compounds 11, 12 and 13 in different
wells on 1% agarose gel and DNA relaxation product was resolved
by gel electrophoresis (BIO-RAD). A well-known drug etoposide
(DNA intercalator, TOPO-II inhibitor) was used as a positive control.
Fig. 4 showed the effect of representative compounds (11, 12,13 and
positive control) on the relaxation of plasmid pHOT1 DNA, medi-
of 1.69
m
M and compound 13 containing N,N-diethyl ethylenedi-
M showed enhanced
M). It is concluded
amine as side chain with GI50 value of 1.53
m
activity as compared to tamoxifen (GI50 ¼ 3.76
m
that compounds 12 and 13 were found to be 2e3 folds more active
than tamoxifen.
ated by topoisomerase-IIa. Among these compounds, compounds
2.3. MTT assay
To evaluate the cytotoxic effect of compounds 11, 12 and 13 on
human normal cell line Hek293, a colorimetric assay (MTT assay)
was performed at five different concentrations of 10ꢀ4, 10ꢀ5, 10ꢀ6
,
10ꢀ7 and 10ꢀ8 M. It has been observed that derivative 11 showed
only 15.82%, 13.73%, 7.04%, 5.43% and 4.74% cytotoxicity to
Hek293 cells whereas compound 12 exhibited 18.89%,15.13%, 9.13%,
6.34% and 5.29%; and compound 13 displayed 20.08%, 16.52%,
14.92%, 14.57%, 8.08% cytotoxicity to Hek293 cells at above said
concentrations (Fig. 3). It revealed that the potent compounds 11,12
and 13 showed low cytotoxicity against normal cells and selectively
kill the cancer cells. These compounds showed only 20% toxicity to
Fig. 4. Effect on relaxation activity of supercoiled pHOT1 plasmid DNA by topoisom-
erase-II . Supercoiled plasmid DNA was incubated with topoisomerase-II , in the
absence (TOPO-II) and in the presence of compounds 11, 12, 13 and etoposide positive
control (PC) at 50 M concentrations.
a
a
Hek293 cells even at 100
mM concentration.
m
Table 3
Compounds 11e13 and TAM with median growth-inhibitory (GI50
,
m
M), total growth-inhibitory (TGI,
m
M) and median lethal concentrations (LC50
,
mM) of in vitro subpanel
cancer cell lines.
Compound
Activity (
mM)
I
II
III
IV
V
VI
VII
VIII
IX
MIG-MIDa
11
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
LC50
GI50
TGI
2.19
5.80
23.9
1.54
3.81
38.61
1.29
3.70
1.50
2.08
6.42
2.90
4.19
12.21
36.33
1.70
3.37
5.85
1.50
3.11
5.87
4.01
9.20
2.60
2.06
5.51
13.75
1.56
3.30
5.64
1.23
2.85
5.93
1.88
5.96
1.77
2.81
9.90
25.21
1.69
3.22
5.87
1.47
2.93
5.45
4.04
10.6
44.14
1.87
3.74
8.55
1.81
3.38
6.11
1.28
2.95
5.46
2.03
5.49
1.70
5.20
16.32
45.84
1.96
3.43
24.00
1.65
3.27
6.04
4.70
11.86
2.78
2.40
7.75
22.03
1.62
2.99
5.71
1.40
2.79
5.47
7.71
1.19
2.59
3.57
12.95
38.45
1.67
3.90
6.11
2.40
4.81
6.39
4.40
11.13
233
3.69
9.08
29.07
1.73
3.58
6.73
1.59
3.54
37.25
3.05
10.38
2.83
3.10
9.25
26.7
1.69
3.36
11.62
1.53
3.32
8.81
3.76
9.01
24.4
12
13
TAM
LC50
I, leukemia; II, non-small cell lung cancer; III, colon cancer; IV, CNS cancer; V, melanoma; VI, ovarian cancer; VII, renal cancer; VIII, prostate cancer; IX, breast cancer.
a
Full panel mean-graph midpoint (
mM). TAM ¼ Tamoxifen.

S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
7
12 and 13 exerted significant but partial inhibitory effect on
topoisomerase-II relaxation at 50 M concentration, as demon-
observed among them, that are in general lower than the suggested
significant threshold (2.5 kcal/mol). These compounds were stabi-
m
strated by the appearance of supercoiled DNA. This data revealed
that triphenylethylene analogues showed antiproliferative activity
through TOPO-II inhibition. Taking into account that compound 11
exerts the low antiproliferative capacity. These data could also
suggest the contribution of the inhibition on topoisomerase-II to
the cytotoxicity.
lized in the active site of TOPO-II through hydrogen bonding, p-p
stacking and hydrophobic interactions (Fig. 5). Compound 11
interacted with residues of TOPO-II via Lys306 (d ¼ 2.59 Å), HIS354
(d ¼ 3.79 Å) and ASN358 (d ¼ 3.62 Å) through hydrogen bonding,
and ILE311 (d ¼ 3.60 Å) and MET61 (d ¼ 5.11 Å) with van der Waal’s
forces (Fig. 5A). Compound 12 is surrounded by PHE308 and LYS357
showing only hydrophobic interaction with TOPO-II (Fig. 5B).
Compound 13 binds with TOPO-II MET 273 (d ¼ 2.35 Å) and TYR274
(d ¼ 2.49 Å) residues by hydrogen bonds; GLU305 (d ¼ 3.92 Å)
2.5. Physicochemical properties
residue by electrostatic-p anionic interactions; and TRP62, TRP361,
ADMET predicts the pharmacokinetic behavior of a molecule
and structural modification in molecule alters its pharmacokinetic
and distribution of a drug [40]. To determine the properties and
drug-like characteristics of compounds 5e19, we have carried out
the theoretical prediction of ADMET parameters (log P, molecular
weight, TPSA, number of hydrogen donors and acceptors, and
Lipinski rule violation) using MedChem_designer 5.5 software [41].
If a compound has log P ꢁ 5, TPSA (topological polar surface
area) ꢁ 140, molecular weight ꢁ 500, number of H acceptor (nNO)
ꢁ10, number of hydrogen bond donor (nNHOH) ꢁ 5, then it is
considered to be a member of biologically active drug family.
S þ log P predict the solubility of the compound in aqueous media
and higher S þ log P value lesser the solubility in an aqueous me-
dium. Compounds violating ADMET and Lipinski’s rule of five [42]
have poor solubility and low absorption. As shown in Table 4, it is
concluded that compounds selected for in vitro anticancer activity
displayed good physiological properties except 9, 10, 17 and 18
where violation is due to either higher molecular weight or log
P > 5. The antitumor activity of compounds 11e13 also supported
the physicochemical parameters where no violation exists.
LYS278 and LYS306 by hydrophobic interactions (Fig. 5C). Reference
drug etoposide fits in the binding pocket of TOPO-II (ARG324,
TRP62, ARG241, SER320, GLN59, GLN310, THR319 residues) through
hydrogen bonding interactions (Fig. 5D).
3. Conclusion
We have identified a novel series of aminopropan-2-ol based E/
Z-tamoxifen and characterized by NMR and HPLC spectroscopy. The
biological data on 60 different human cancer cell lines at one dose
and five dose concentration levels showed interesting activity for
most of the described compounds. The presence of primary amines
viz., (2-aminoethyl)morpholine (11), cyclohexylamine (12) and N,N-
diethylethylenediamine (13) at the side chain seems to improve the
cytotoxic activity due to increase in the ability of hydrogen donor
while most of the secondary amines of the tamoxifen skeleton
don’t affect positively on the cytotoxicity of the compound. MTT
assay towards normal cell line Hek293 suggests that these com-
pounds could kill selectively cancer cells and not normal cells.
Further biological experiments point out TOPO-II as a possible
intracellular target responsible for the cytotoxicity of these com-
pounds. Furthermore, a docking study was performed and pre-
dicted the binding of compounds with TOPO-II by forming H-bond,
van der Waal’s interaction and hydrophobic interaction. In
conclusion, interestingly, notwithstanding the common general
2.6. Molecular docking
Molecular docking studies were performed to understand the
intermolecular interactions between the topoisomerase-II (PDB
code: 1ZXM) and the ligands (11, 12 and 13) using AutoDock vina
software 4.0 and compare with etoposide [43]. Docked structure of
compound 12 showed different binding sites than compounds 11
and 13 which share the same binding site. The binding energy
scores for ligands 11, 12, 13 and etoposide (reference drug) were
calculated to be ꢀ7.2, ꢀ6.0, ꢀ6.8 and ꢀ9.1 kcal/mol, respectively;
suggesting a strong binding affinity of tamoxifen derivatives for the
proposed binding sites, although it was not possible to effectively
rank the compounds, due to the small binding energy differences
triarylskeleton, here reported tamoxifen analogues show
a
different biological profile with respect to the reference drug, being
more cytotoxic on non-estrogenic cell lines and affecting the cat-
alytic activity of the topoisomerase-II. Altogether, these results
show various aminopropan-2-ol as an interesting side chain for the
obtainment of new anticancer compounds. Altogether, the biolog-
ical screening results showed triphenylethylene derivatives as an
interesting scaffold and gives new insight into the development of
Table 4
Physicochemical properties of triphenylethylene analogue 5e19 and reference drug tamoxifen.
Entry
Diff. Coeff.
MlogP
S þ logP
TPSA
Mol. Wt.
nNO
nNHOH
nviolation
5
6
7
8
0.574
0.583
0.564
0.551
0.527
0.516
0.547
0.560
0.539
0.564
0.594
0.574
0.560
0.571
0.583
0.610
4.568
3.564
3.760
3.953
4.754
4.660
3.165
4.761
4.345
3.956
4.494
4.764
5.129
5.571
3.237
5.201
5.750
5.061
4.981
5.224
6.584
6.277
4.847
6.247
5.519
5.109
5.081
5.954
6.136
6.797
4.949
6.642
32.70
41.93
35.94
35.94
35.94
35.94
53.96
41.49
44.73
44.73
41.49
41.49
41.49
41.49
67.27
12.47
427.59
429.56
442.60
456.63
504.67
518.70
472.63
441.62
458.65
430.59
399.54
415.57
449.59
453.56
437.54
371.52
3
4
4
4
4
4
5
3
4
4
3
3
3
3
5
2
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
0
none
none
none
none
1
9
10
11
12
13
14
15
16
17
18
19
TAM
1
none
none
none
none
none
none
1
1
none
1
TAM ¼ Tamoxifen.

8
S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
Fig. 5. Binding poses showing interactions of compounds 11 (A), 12 (B), 13 (C) and etoposide (D) with TOPO-II (PDB code: 1ZXM).
novel anticancer drugs.
evaporated. A yellow colored oily product was collected. The crude
was purified by column chromatography using eluents hexane-
ethyl acetate (97:3) to obtain the desired product. Finally, the
chromatographed product was washed with hexane to afford
white-colored precipitates of E/Z diastereomers in 1:1; 80% yield;
4. Experimental section
4.1. General procedure
mp. 145e148 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m, 2H,
ArH), 7.23e7.21 (m, 3H, ArH), 7.18e7.05 (m, 12H, ArH), 7.03e6.96
(m, 3H, ArH), 6.89e6.84 (dd, 2H, ArH), 6.81e6.77 (m, 2H, ArH),
6.75e6.71 (m, 2H, ArH), 6.49e6.45 (m, 2H, ArH), 4.81 (s, 1H, OH),
4.59 (s, 1H, OH), 2.14 (s, 3H, CH3), 2.10 (s, 3H, CH3); 13C NMR
All substrates, reagents, and solvents were purchased from
Aldrich, Spectrochem, TCI and used without further purification.
Reactions were carried out using dry solvent under nitrogen at-
mosphere. Melting points were determined in open capillaries and
were uncorrected. Reactions were monitored by thin-layer chro-
matography using silica gel GF-254 and visualized by UV light.
Column chromatography was performed using silica gel of mesh
size 60e120.1H and 13C NMR were recorded on Jeol spectrometer
(400 MHz for 1H and 100 MHz for 13C) using CDCl3 as a solvent.
Chemical shifts are reported in parts per million (ppm) with TMS as
an internal reference. Mass spectra of the synthesized compounds
were observed at Water Micromass-Q-T of Micro.
(100 MHz, CDCl3)
d 154.22, 153.54, 144.32, 144.27, 143.81, 143.42,
138.84, 138.73, 136.21, 135.85, 135.41, 134.95, 132.28, 131.53, 131.02,
130.12, 129.42, 129.40, 128.19, 128.01, 127.93, 127.46, 126.64, 126.19,
126.18, 125.86, 115.00, 114.43 (AreC), 23.52 (CH3), 23.44(CH3); MS:
287.1 [Mþ1]þ.
4.2.2. 2-((4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)methyl)oxirane
(4)
4-(1,2-Diphenylprop-1-en-1-yl)phenol (1.0 g, 3.5 mmol) 3 was
refluxed with epichlorohydrin (2.73 mL, 34.9 mmol) in the pres-
ence of potassium carbonate (0.58 g, 4.1 mmol) in acetonitrile for
16 h. After the completion of reaction, the solvent was evaporated
under reduced pressure. Then the product was extracted from
aqueous layer using CHCl3. On removal of chloroform, the white
colored semi-solid product was obtained. The crude was further
purified by column chromatography by employing hexane-
ethylacetate (98:2) as solvent system to obtain white solid of E/Z
3.4:1; 65% yield; mp. 58e62 ꢂC; 1H NMR (400 MHz, CDCl3)
4.2. Synthesis
4.2.1. 4-(1,2-Diphenylprop-1-en-1-yl)phenol (3)
To a two-necked oven-dried round bottom flask, a suspension of
zinc (1.61 g, 25.2 mmol) in 20 mL of dry THF was stirred at 0e5 ꢂC
for 15 min. To the stirred suspension, the slow addition of TiCl4
(1.38 mL, 12.6 mmol) was done carefully with the help of a syringe
under the inert atmosphere of nitrogen. After the complete addi-
tion of TiCl4, the resulting black mixture was stirred at room tem-
perature for 30 min and then allowed to reflux for 3 h. The reaction
mixture was gradually cooled to 0 ꢂC and was charged with pyri-
dine (0.5 mL, 6.3 mmol), and further stirred for 15 min. A solution of
4-hydroxy benzophenone (0.5 g, 2.5 mmol) and acetophenone
(0.29 mL, 2.5 mmol) in dried THF was added slowly to the reaction
mixture. The reaction was refluxed for 2.5 h. The reaction was
monitored by TLC. After the completion of the reaction, it was
quenched by the addition of a 10% aqueous solution of K2CO3 till
neutralization. Then, the quenched solution was filtered off. From
the filtrate, the crude product was extracted with chloroform. The
organic layer was dried over sodium sulfate and the solvent was
d
7.35e7.28 (m, 1H), 7.24e7.19 (m, 1H), 7.17e7.08 (m, 10H),
6.90e6.76 (m, 5H), 6.79e6.76 (m, 1H), 6.59e6.54 (m, 1H), 4.22 (dd,
1H, J ¼ 11.0, J ¼ 3.24 Hz, OCH2), 4.18 (dd, 1H, J ¼ 11.04, J ¼ 3.24 Hz,
OCH2), 3.97 (dd, 1H, J ¼ 10.60, J ¼ 5.64 Hz, OCH2), 3.82 (dd, 1H,
J ¼ 10.92, J ¼ 5.64 Hz, OCH2), 3.38e3.33 (m, 1H, CH-epoxy),
3.29e3.25 (m, 1H, CH-epoxy), 2.92e2.87 (m, 1H, CH2-epoxy),
2.86e2.83 (m, 1H, CH2-epoxy), 2.77e2.73 (m, 1H, CH2-epoxy),
2.69e2.67 (m, 1H, CH2-epoxy), 2.14 (s, 3H, CH3), 2.10 (s, 3H, CH3);
13C NMR (100 MHz, CDCl3)
d 157.28, 156.61, 144.33, 144.30, 143.86,
143.45, 138.92, 138.80, 136.65, 136.64, 136.23, 135.53, 135.10, 132.17,
131.43, 131.07, 130.17, 129.47, 129.44, 128.26, 128.10, 128.00, 127.54,

S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
9
126.71, 126.27, 125.94, 114.28, 113.62 (AreC), 68.88 (OCH2), 68.61
(OCH2), 50.30 (epoxy OCH), 50.20 (epoxy OCH), 44.89 (epoxy
OCH2), 44.86 (epoxy OCH2), 23.59 (CH3), 23.53 (CH3); MS: 343.1
[Mþ1]þ.
1H), 7.24e7.22 (m, 1H), 7.16e7.07 (m, 9H), 7.02e6.98 (m, 3H),
6.90e6.86 (m, 4H), 6.78e6.76 (m, 1H), 6.58e6.55 (m, 1H),
4.14e4.08 (m, 1H, OCH2), 4.05e4.01 (m, 1H, OCH2), 4.00 (s, 1H, CH),
3.98 (s, 1H, CH), 3.85e3.83 (m, 1H, OCH2), 2.74e2.39 (m, 17H), 2.14
(s, 3H, CH3), 2.11 (s, 2H, CH3), 1.11e1.08 (m, 5H, NeCH3); 13C NMR
4.2.3. General procedure for the synthesis of triarylethylene
analogous 5e19
(100 MHz, CDCl3) d 157.43, 156.73, 144.27, 143.84, 143.41, 138.89,
138.76, 136.35, 135.93, 132.04, 131.00, 130.99, 130.09, 129.39, 128.16,
128.00, 127.90, 127.43, 126.59, 126.16, 125.83, 114.59, 114.10, 113.47
(AreC), 70.27 (OCH2), 70.03 (OCH2), 65.55 (CeOH), 65.49 (CeOH),
60.55 (NCH2), 60.48 (NCH2), 52.82 (pip-NCH2), 52.33 (pipalkyl-
NCH2), 23.50 (CH3), 23.44 (CH3), 11.97 (pipalkyl-CH3); MS: 457.3
[Mþ1]þ.
To a solution of 2-2-((4-(1,2-diphenylprop-1-en-1-yl)phenoxy)
methyl)oxirane 4 (0.10 g, 0.2 mmol) in acetonitrile, K2CO3 (0.048 g,
0.35 mmol) was added and the solution was refluxed with various
primary and secondary amines (1.4 mmol) for 3e4 h until the
completion of reaction. After removal of solvent under reduced
pressure, water was added to the reaction mixture and extracted
with chloroform. The obtained residues were purified by column
chromatography using different ratios of hexane-ethyl acetate as
eluents to give compounds 5e19.
4.2.3.5. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-(4-
phenylpiperazin-1-yl)propan-2-ol (9). White solid, E/Z: 2.3:1; Yield
75%; mp:141e143 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m,
1H), 7.28e7.26 (m, 2H), 7.23e7.21 (m, 1H), 7.16e7.06 (m, 10H),
7.03e6.97 (m, 3H), 6.94e6.83 (m, 9H), 6.79e6.75 (m, 1H),
6.59e6.55 (m, 1H), 4.77 (s, 2H, OH), 4.18e4.11 (m, 1H, OCH2),
4.10e4.04 (m, 1H, OCH2), 4.02 (s, 1H, OCH), 4.01 (s, 1H, OCH),
3.97e3.96 (m, 1H, OCH2), 3.87e3.86 (m, 1H, OCH2), 3.26e3.17 (m,
7H, pip-CH2), 2.87e2.76 (m, 4H, pip-CH2), 2.68e2.48 (m, 7H), 2.14
4.2.3.1. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-(piperidin-1-
yl)propan-2-ol (5). White solid, E/Z: 2.2:1; Yield 75%; mp:
125e127 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m, 1H),
7.24e7.20 (m, 1H), 7.15e7.07 (m, 9H), 7.02e6.97 (m, 3H), 6.90e6.84
(m, 4H), 6.77e6.74 (m, 1H), 6.58e6.54 (m, 1H), 4.12e4.06 (m, 1H,
OCH3), 4.01e3.99 (m, 1H, OCH3), 3.98e3.97 (m, 1H, OCH) 3.96e3.94
(m, 1H, OCH), 3.85e3.79 (m, 1H, OCH2), 3.49e3.44 (m, 1H, OCH2),
2.61 (br, s, 4H, pip-NCH2), 2.51 (m, 1H, OCH2), 2.48e2.29 (m, 5H),
2.13 (s, 3H, CH3), 2.09 (s, 3H, CH3), 1.53e1.64 (m, 6H, pip-CH2),
(s, 3H, CH3), 2.10 (s, 2H, CH3); 13C NMR (100 MHz, CDCl3)
d 157.28,
156.60, 151.12, 144.14, 143.29, 138.74, 138.61, 136.29, 135.90, 135.31,
134.90, 131.96, 131.22, 130.89, 129.99, 129.87, 129.29, 129.13, 128.79,
128.72, 128.42, 128.34, 128.06, 127.90, 127.80, 127.33, 126.50, 126.07,
125.98, 125.73, 119.91, 116.13, 114.47, 113.98, 113.35 (AreC), 70.06
(OCH2), 69.83 (OCH2), 65.54 (CeOH), 65.48 (CeOH), 60.52 (NCH2),
60.45 (NCH2), 53.28 (pip-NCH2), 53.25 (pip-NCH2), 49.26 (pip-
NCH2), 49.23 (pip-NCH2), 23.40 (CH3), 23.34 (CH3); MS: 505.3
[Mþ1]þ.
1.46e1.41 (m, 3H, CH2); 13C NMR (100 MHz, CDCl3)
d 157.50, 144.29,
143.43, 138.91, 136.27, 135.36, 131.20, 131.00, 129.40, 127.90, 127.42,
126.15, 125.82, 114.10 (AreC), 70.41 (CH2eO), 65.35 (CeOH), 61.31
(CeN), 54.81 (pip-NCH2), 26.07 (CH2-pip), 24.25 (CH2-pip), 23.51
(CH3); MS: 428.2 [Mþ1]þ.
4.2.3.2. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-
4.2.3.6. 1-(4-Benzylpiperazin-1-yl)-3-(4-(1,2-diphenylprop-1-en-1-
morpholinopropan-2-ol (6). White solid, E/Z: 3:1; Yield 77%; mp:
yl)phenoxy)propan-2-ol (10). White solid, E/Z: 2:1; Yield 74%; mp:
124e127 ꢂC; 1H NMR (400 MHz, CDCl3)
d
7.91 (br, s, 1H), 7.42e7.25
142e144 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.30 (m, 8H),
(m, 5H), 7.13e6.58 (m, 5H), 4.13e3.86 (m, 8H), 4.01 (s, 2H, OCH),
3.74 (s, 8H, morph OeCH2), 3.06e2.86 (s, 4H), 2.67e2.32 (m, 14H),
2.15 (s, 3H, CH3), 2.11 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3)
7.27e7.24 (m, 2H), 7.23e7.22 (m, 1H), 7.18e7.06 (m, 10H), 7.03e6.98
(m, 3H), 6.90e6.86 (m, 4H), 6.78e6.75 (m, 1H), 6.57e6.55 (m, 1H),
5.02 (br, s, 2H, OH), 4.15e4.02 (m, 2H, OCH2), 3.99 (s, 1H, OCH), 3.98
(s, 1H, OCH), 3.53 (s, 2H, benzyl-CH2), 3.51 (s, 2H, benzyl-CH2),
2.82e2.39 (m, 1H), 2.14 (s, 3H, CH3), 2.11 (s, 2H, CH3); 13C NMR
d
157.36, 156.68, 144.29, 144.24, 143.82, 143.39, 138.84, 138.71,
136.41, 136.00, 135.42, 134.96, 132.06, 131.32, 130.99, 130.09, 129.39,
128.16, 128.00, 127.91, 127.44, 126.60, 126.18, 126.15, 125.84, 114.08,
113.45 (AreC), 70.13 (OCH2), 69.88 (OCH2), 67.10 (morph-OCH2),
67.08 (morph-OCH2), 65.43 (OCH), 65.37 (OCH), 61.13 (NeCH2),
61.05 (NeCH2), 53.80 (morph-NCH2), 23.50 (CH3), 23.44 (CH3); MS:
430.2 [Mþ1]þ.
(100 MHz, CDCl3)
d 157.42, 156.74, 144.29, 144.28, 143.85, 143.42,
138.89, 138.76, 137.83, 136.34, 135.93, 135.39, 134.92, 132.07, 131.32,
131.02, 130.12, 129.97, 129.42, 129.37, 129.27, 128.91, 128.39, 128.18,
128.02, 127.93, 127.45, 127.29, 126.62, 126.18, 125.85, 114.59, 114.10,
113.47 (AreC), 70.26 (OCH2), 70.01 (OCH2), 65.43 (CeOH), 65.36
(CeOH), 62.98 (NCH2), 60.60 (benzyl-C), 60.53 (benzyl-C), 53.27
(pip-NCH2), 52.86 (pip-NCH2), 23.53 (CH3), 23.47 (CH3); MS: 519.3
[Mþ1]þ.
4.2.3.3. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-(4-
methylpiperazin-1-yl)propan-2-ol (7). White solid, E/Z: 1.75:1; Yield
78%; mp: 132e135 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.30 (m,
1H), 7.23e7.20 (m, 2H), 7.15e7.06 (m, 9H), 7.02e6.95 (m, 3H),
6.90e6.84 (m, 4H), 6.74e6.78 (m, 1H), 6.57e6.54 (m, 1H), 4.12e4.06
(m, 1H, OCH2), 4.03e4.00 (m, 1H, OCH2), 3.98 (br, s, 1H, CH), 3.97
(br, s, 1H, CH), 3.84e3.82 (m, 1H, OCH), 2.70e2.40 (m, 14H), 2.28 (s,
4.2.3.7. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-((2-
morpholinoethyl)amino)propan-2-ol (11). White solid, E/Z: 1.33:1;
Yield 76%; mp: 137e140 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.31
(m, 2H), 7.24e7.19 (m, 2H), 7.17e7.06 (m, 11H), 7.00e6.97 (m, 3H),
6.89e6.84 (m, 4H), 6.78e6.74 (m, 2H), 6.56e6.52 (m, 2H), 4.16e4.10
(m, 1H, OCH2), 4.06e4.01 (m, 1H, OCH2), 4.00e3.95 (m, 2H, OCH),
3.87e3.80 (m, 2H, OCH2), 3.70e3.65 (m, 7H, morpho-CH2),
3.15e2.73 (m, 12H), 2.56e2.49 (m, 4H), 2.46e2.43 (m, 7H, morpho-
CH2), 2.13 (s, 3H, CH3), 2.09 (s, 3H, CH3); 13C NMR (100 MHz, CDCl3)
3H, NeCH3), 2.27 (s, 3H, NeCH3), 2.13 (s, CH3), 2.09 (s, 3H, CH3); 13
C
NMR (100 MHz, CDCl3)
d 157.42, 156.74, 144.29, 144.26, 143.83,
143.40, 138.87, 138.74, 136.35, 135.93, 135.39, 134.92, 132.04, 131.30,
130.99, 130.09, 129.39, 128.16, 128.00, 127.90, 127.43, 126.59, 126.16,
125.82, 114.09, 113.46 (AreC), 70.24 (OCH2), 70.00 (OCH2), 65.55
(CeOH), 65.48 (CeOH), 60.51 (CeN), 60.44 (CeN), 55.19 (pip-
NCH2), 46.06 (pip-NCH3), 23.50 (CH3), 23.43 (CH3); MS: 443.2
[Mþ1]þ.
d
157.36, 156.68, 144.29, 144.23, 143.82, 143.39, 138.84, 138.70,
136.39, 135.97, 135.41, 134.96, 132.08, 131.33, 130.99, 130.09, 129.98,
129.39, 128.88, 128.53, 128.17, 128.01, 127.91, 127.44, 126.61, 126.10,
125.85, 114.56, 114.07, 113.44 (AreC), 70.38 (OCH2), 70.16 (OCH2),
68.50 (CeOH), 68.44 (CeOH), 67.09 (morph-OC), 67.00 (morph-
OC), 58.26 (ethylene-NC), 53.78 (morph-NC), 53.72 (morph-NC),
51.86 (NCH2), 51.80 (CH2), 45.82 (ethylene-NHC), 23.50 (CH3), 23.46
4.2.3.4. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-(4-
ethylpiperazin-1-yl)propan-2-ol (8). White solid, E/Z: 1.6:1; Yield
72%; mp: 136e138 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m,

10
S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
(CH3); MS: 473.29 [Mþ1]þ.
156.55, 144.28, 144.24, 143.81, 143.75, 143.39, 138.84, 138.71, 136.47,
136.07, 135.43, 134.99, 134.65, 134.55, 132.23, 132.10, 131.36, 131.00,
130.11, 130.02, 129.40, 128.89, 128.53, 128.18, 128.02, 127.92, 127.45,
126.62, 126.19, 125.85, 118.77 (allyl-CH2), 114.58, 114.48, 114.10,
113.47 (AreC), 70.17 (OCH2), 70.14 (OCH2), 68.12 (CeOH), 68.05
(CeOH), 52.31 (NCH2), 52.26 (NCH2), 41.10 (allyl-NCH2), 23.52
(CH3), 23.46 (CH3); MS: 400.2 [Mþ1]þ.
4.2.3.8. 1-(Cyclohexylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phe-
noxy)propan-2-ol (12). White solid, E/Z: 2.3:1; Yield 80%; mp:
135e138 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.30 (m, 1H),
7.22e7.20 (m, 1H), 7.16e7.05 (m, 10H), 7.02e6.96 (m, 3H),
6.89e6.83 (m, 4H), 6.78e6.74 (m,1H), 6.57e6.53 (m, 1H), 4.01e3.87
(m, 4H), 3.83e3.81 (m, 1H, OCH2), 2.93e2.89 (m, 1H, CH2),
2.85e2.81 (m, 1H, CH2), 2.76e2.71 (m, 1H, CH2), 2.68e2.63 (m, 1H,
CH2), 2.45e2.35 (m, 2H, cyclohexyl-CH), 2.13 (s, 3H, CH3), 2.03 (s,
3H, CH3), 1.91e1.84 (m, 4H, cyclohexyl-NCH2), 1.74e1.68 (m, 4H,
CH2), 1.61e1.57 (m, 4H, cyclohexyl-NCH2), 1.29e1.19 (m, 4H, CH2),
4.2.3.12. 1-(Butylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phenoxy)
propan-2-ol (16). White solid, E/Z: 2.4:1; Yield 85%; mp:
119e121 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.30 (m, 1H),
7.22e7.20 (m, 1H), 7.15e7.07 (m, 9H), 7.00e6.98 (m, 3H), 6.88e6.86
(m, 4H), 6.71e6.69 (m, 1H), 6.55e6.45 (m, 1H), 4.06 (s, 1H, OCH2),
3.97e3.96 (m, 2H, OCH), 3.92e3.81 (m, 1H, OCH2), 3.25e3.16 (m,
1H, OCH2), 2.86e2.58 (m, 4H, OCH), 2.33e2.29 (m, 3H, butyl-NCH2),
2.13 (s, 3H, CH3), 2.09 (s, 2H, CH3), 1.57e1.43 (m, 3H, butyl-CH2),
1.36e1.31 (m, 3H, butyl-CH2), 0.92e0.87 (m, 4H, butyl-CH3); 13C
1.16e1.00 (m, 4H, CH2); 13C NMR (100 MHz, CDCl3)
d 157.34, 156.71,
144.29, 144.25, 143.40, 138.86, 138.72, 136.36, 136.29 135.98, 135.88,
135.39, 135.32, 134.99, 134.93, 132.06, 131.31, 130.99, 130.09, 129.39,
128.16, 128.00, 127.90, 127.43, 126.59, 126.16, 125.83, 114.09, 113.45
(AreC), 70.46 (OCH2), 70.24 (OCH2), 68.53 (CeOH), 68.48 (CeOH),
56.84 (NCH2), 56.80 (NCH2), 48.83 (cyclohexyl-NCH), 48.76
(cyclohexyl-NCH), 34.03 (cyclohexyl-C), 33.98 (cyclohexyl-C), 33.79
(cyclohexyl-C), 33.75 (cyclohexyl-C), 26.15 (cyclohexyl-C), 25.11
(cyclohexyl-C), 23.49 (CH3), 23.44 (CH3); MS: 442.2 [Mþ1]þ.
NMR (100 MHz, CDCl3)
d 157.15, 156.78, 144.24, 144.09, 143.24,
138.69, 138.55, 136.27, 135.31, 135.26, 132.05, 131.93, 131.29, 131.18,
130.84, 129.95, 129.24, 128.01, 127.98, 127.86, 127.81, 127.76, 127.29,
126.46, 126.40, 126.03, 125.94, 125.69, 125.62, 114.98, 114.41, 113.93,
113.29 (AreC), 70.28 (OCH2), 70.06 (OCH2), 68.00 (CeOH), 67.94
(CeOH), 51.66 (NCH2), 51.60 (NCH2), 49.41 (butyl-NCH), 31.90
(butyl-C), 31.54 (butyl-C), 23.35 (CH3), 20.30 (butyl-C), 14.10 (butyl-
C), 13.94 (butyl-C); MS: 416.2 [Mþ1]þ.
4.2.3.9. 1-(Diethylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phe-
noxy)propan-2-ol (13). White solid, E/Z: 2.5:1; Yield 78%; mp:
130e132 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m, 1H),
7.24e7.22 (m, 1H), 7.16e7.08 (m, 9H), 7.01e6.96 (m, 3H), 6.90e6.88
(m, 4H), 6.79e6.77 (m, 1H), 6.58e6.56 (m, 1H), 4.09e4.05 (m, 1H,
OCH2), 4.02e3.91 (m, 3H), 3.86e3.79 (m, 1H, OCH2), 3.32 (br, s, 2H,
NH), 2.90e2.69 (m, 6H), 2.58e2.49 (m, 9H), 2.15 (s, 3H, CH3), 2.12 (s,
1H, CH3), 1.04e0.98 (m, 9H, N,N- diethyl CH3); 13C NMR (100 MHz,
4.2.3.13. 1-(Benzylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phe-
noxy)propan-2-ol (17). White solid, E/Z: 2:1; Yield 67%; mp:
133e135 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.26 (m, 9H),
7.22e7.20 (m, 2H), 7.02e6.98 (m, 3H), 6.89e6.81 (m, 4H), 6.77e6.74
(m, 1H), 6.56e6.53 (m, 1H), 4.10e4.05 (m, 2H, OCH2), 3.99e3.97 (m,
2H, OCH), 3.84e3.78 (m, 2H, OCH2), 3.51 (s, 2H, benzyl-CH2), 3.49
(s, 1H, benzyl-CH2), 2.77e2.69 (m, 2H, CH), 2.53e2.47 (m, 2H, CH),
2.13 (s, 3H, CH3), 2.09 (s, 2H, CH3); 13C NMR (100 MHz, CDCl3)
CDCl3)
d 157.42, 156.74, 144.31, 144.28, 143.86, 143.42, 138.91,
138.77, 136.32, 135.91, 135.39, 134.92, 132.06, 131.39, 131.31, 131.00,
130.10, 129.41, 129.38, 128.17, 128.02, 127.92, 127.45, 126.68, 126.18,
125.84, 114.12, 113.49 (AreC), 70.42 (OCH2), 70.19 (OCH2), 68.03
(CeOH), 67.96 (CeOH), 52.31 (NHCH2), 52.26 (NHCH2), 52.00
(ethylene-NCH2), 51.92 (ethylene-NCH2), 46.93 (ethylene-NHCH2),
46.85 (N,N-diethyl CH2), 23.52 (CH3), 23.46 (CH3), 11.42 (N,N-
diethyl CH3); MS: 459.3 [Mþ1]þ.
d
157.44, 156.70, 144.28, 143.85, 143.43, 138.90, 138.77, 137.97,
136.34, 135.93, 135.39, 134.92, 132.06, 131.32, 131.02, 130.12, 129.97,
129.42, 129.36, 129.20, 128.53, 128.49, 128.37, 128.18, 128.02, 127.93,
127.45, 127.25, 126.60, 126.18, 126.09, 125.85, 114.60, 114.11, 113.48
(AreC), 70.27 (OCH2), 70.03 (OCH2), 65.50 (CeOH), 65.45 (CeOH),
60.72 (benzyl-C), 60.49 (benzyl-C), 53.45 (NCH2), 53.14 (NCH2),
23.53 (CH3), 23.47 (CH3); MS: 450.2 [Mþ1]þ.
4.2.3.10. 1-(Dimethylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phe-
noxy)propan-2-ol (14). White solid, E/Z: 3.5:1; Yield 75%; mp:
127e129 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.34e7.30 (m, 1H),
7.22e7.20 (m, 1H), 7.14e7.06 (m, 14H), 7.00e6.95 (m, 3H),
6.88e6.85 (m, 4H), 6.77e6.72 (m, 1H), 6.56e6.54 (m, 1H),
4.06e4.00 (m, 2H, OCH2), 3.98e3.93 (m, 2H, OCH), 3.82e3.81 (m,
1H, OCH2), 2.89e2.66 (m, 6H), 2.47e2.29 (m, 5H), 2.22 (s, 6H,
dimethyl-NCH3), 2.20 (s, 2H, dimethyl-NCH3), 2.13 (s, 3H, CH3), 2.09
4.2.3.14. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-((4-
fluorophenyl)amino)propan-2-ol (18). White solid, E/Z: 12.5:1; Yield
70%; mp: 134e137 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e726 (m,
1H), 7.17e7.05 (m, 8H), 7.03e6.96 (m, 3H), 6.92e6.84 (m, 6H),
6.63e6.59 (m, 2H), 4.25e4.24 (m, 1H, OCH2), 4.10e4.02 (m, 2H,
OCH), 3.98e3.91 (m, 1H, OCH2), 3.49e3.43 (m, 1H, CH), 3.40e3.36
(m, 1H, CH), 3.29e3.22 (m, 1H, CH), 2.13 (s, 3H, CH3), 2.10 (s, 3H,
(s, 3H, CH3); 13C NMR (100 MHz, CDCl3)
d 157.43, 156.73, 144.27,
138.88, 138.75, 136.29, 135.88, 135.37, 134.90, 132.05, 131.30, 131.00,
130.10, 129.95, 129.40, 128.16, 128.01, 127.90, 127.43, 126.59, 126.16,
126.07, 125.82, 114.09, 113.46 (AreC), 70.39 (OCH2), 70.17 (OCH2),
68.53 (CeOH), 68.47 (CeOH), 59.21 (ethylene-NCH2), 51.96 (NCH2),
51.89 (NCH2), 47.02 (ethylene-NHC), 45.50 (ethylene-NCH3), 23.50
(CH3), 23.44 (NCH3); MS: 431.2 [Mþ1]þ.
CH3); 13C NMR (100 MHz, CDCl3)
d 157.04, 144.48, 144.17, 143.34,
138.74, 136.79, 135.56, 131.45, 130.99, 129.40, 127.95, 127.49, 126.25,
125.91, 115.97, 115.75, 114.34, 114.26, 114.10 (AreC), 70.06 (OCH2),
68.83 (CeOH), 47.34 (NCH2), 23.51 (CH3); MS: 453.2 [Mþ1]þ.
4.2.3.15. 1-(4-(1,2-Diphenylprop-1-en-1-yl)phenoxy)-3-(pyrazin-2-
4.2.3.11. 1-(Allylamino)-3-(4-(1,2-diphenylprop-1-en-1-yl)phenoxy)
ylamino)propan-2-ol (19). White solid, E/Z: 1.5:1; Yield 65%; mp:
propan-2-ol (15). White solid, E/Z: 1.7:1; Yield 68%; mp:
148e150 ꢂC; 1H NMR (400 MHz, CDCl3)
d 7.35e7.31 (m, 2H), 7.22
120e123 ꢂC; 1H NMR (400 MHz, CDCl3)
d
7.34e7.31 (m, 1H),
(m, 1H), 7.14e7.09 (m, 12H), 7.01e6.99 (m, 4H), 6.90e6.86 (m, 3H),
6.80e6.78 (m, 2H), 6.72e6.74 (m, 2H), 4.78 (br, s, 1H, NH), 4.55 (br,
s, 1H, NH), 4.22e3.95 (m, 3H), 2.54e2.40 (m, 2H, CH2), 2.14 (s, 1H,
CH3), 2.10 (s, 1H, CH3); MS: 438.2 [Mþ1]þ.
7.23e7.20 (m, 1H), 7.17e7.05 (m, 10H), 7.02e6.95 (m, 3H),
6.89e6.85 (m, 4H), 6.78e6.75 (m, 1H), 6.56e6.52 (m, 1H),
5.91e5.77 (m, 1H, allyl-CH), 5.24e5.12 (m, 2H, allyl CH2), 4.16e4.07
(m, 1H, OCH2), 4.05e4.01 (m, 1H, OCH2), 3.99e3.94 (m, 2H, OCH),
3.87e3.79 (m, 1H, OCH2), 3.49e3.44 (m, 1H, OCH2), 3.40e3.17 (m,
2H, allyl-NCH2), 2.88e2.58 (m, 3H, CH2), 2.13 (s, 3H, CH3), 2.10 (s,
4.3. HPLC chromatography
2H, CH3); 13C NMR (100 MHz, CDCl3)
d
157.28, 157.24, 156.59,
To analyze the ratio of E- and Z-isomers of the triphenylethylene

S. Rani, K. Paul / European Journal of Medicinal Chemistry 208 (2020) 112775
11
derivatives, reversed-phase high-performance liquid chromatog-
interactions were converted to the required pdbqt format.
raphy (RP-HPLC) has been performed using Ultimate 3000 HPLC
(Thermofisher Scientific) system, equipped with C-18 column
(250 ꢃ 4.6 mm, 5 mm) and UVevis detector. The wavelength used
was 276 nm and the mobile phase was comprised of 0.01 M tet-
rabutylammonium hydrogen sulfate: methanol: acetonitrile
(5:10:85; v/v/v) with flow rate 1.0 mL/min. The stock solution of E/Z
triphenylethylene derivative i.e. 5 (1 mM) was prepared in aceto-
nitrile and protected from direct light. The stock solution was then
Declaration of competing interest
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
Acknowledgments
diluted to produce
a solution of compound in acetonitrile
(2.3 ꢃ 10ꢀ4 M). First, the prepared sample was filtrated using
KP thanks the CSIR, New Delhi [(02(0310)/17/EMR-II] and SERB,
New Delhi (CRG/2018/002159) for financial support. The authors
express their gratitude to NCI, NIH for antiproliferative activity.
0.22 mm cellulose filtrate. Then, 20 ml of the filtered sample was
injected into the column with an injection loop.
4.4. Biological evaluation
Appendix A. Supplementary data
4.4.1. MTT assay
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.ejmech.2020.112775.
The cytotoxicity of triphenylethylene derivatives 11e13 was
determined using MTT assay. Hek293 human embryonic kidney
cells were seeded in 96 well plates at the density of 1 ꢃ 10ꢀ5 cells/
well in low glucose Dulbecco’s modified Eagle’s medium (DMEM)
containing 10% fetal bovine serum (FBS), 50 mM glutamine, 100 U/
ml penicillin and 100 mg/mL streptomycin. Cells were incubated at
37 ꢂC in an atmosphere of 5% CO2 incubator. Cells were treated with
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