Synthesis and biological evaluation of 1-benzylidene-3,4-dihydronaphthalen- 2-one as a new class of microtubule-targeting agents

Article abstract of DOI:10.1021/jm300596s

A series of 1-benzylidene-3,4-dihydronaphthalen-2-one derivatives were designed and synthesized, and their biological activities in vitro and in vivo were evaluated. The results showed a number of the title compounds exhibiting potent nanomolar activity in several human cancer cell lines. Of these, compound 22b showed the strongest inhibitory activity against human CEM, MDA-MBA-435, and K562 cells (IC₅₀ = 1 nM), displayed in vitro inhibition of tubulin polymerization (IC₅₀ = 3.93 μM), and significantly induced cell cycle arrest in G2/M phase. In addition, compound 22b could inhibit the tumor growth in colon nude mouse xenograft tumor model significantly and seemed safer than CA-4 when achieving a similar tumor suppression. This study provided a new molecular scaffold for the further development of antitumor agents that target tubulin.

Full text of DOI:10.1021/jm300596s

Article
pubs.acs.org/jmc
Synthesis and Biological Evaluation of 1-Benzylidene-3,
4-dihydronaphthalen-2-one as a New Class of
Microtubule-Targeting Agents
Jia Liu,† Can-Hui Zheng,*,† Xiao-Hui Ren, Feng Zhou, Wei Li, Ju Zhu, Jia-Guo Lv,* and You-Jun Zhou*
School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
ABSTRACT: A series of 1-benzylidene-3,4-dihydronaphthalen-2-one derivatives were
designed and synthesized, and their biological activities in vitro and in vivo were evaluated.
The results showed a number of the title compounds exhibiting potent nanomolar activity in
several human cancer cell lines. Of these, compound 22b showed the strongest inhibitory
activity against human CEM, MDA-MBA-435, and K562 cells (IC50 = 1 nM), displayed in
vitro inhibition of tubulin polymerization (IC50 = 3.93 μM), and significantly induced cell
cycle arrest in G2/M phase. In addition, compound 22b could inhibit the tumor growth in
colon nude mouse xenograft tumor model significantly and seemed safer than CA-4 when
achieving a similar tumor suppression. This study provided a new molecular scaffold for the
further development of antitumor agents that target tubulin.
shutdown to induce widespread necrosis in solid tumors.12−14
INTRODUCTION
Microtubule arrangement and rearrangement play important
■
Then a large number of structurally diverse CA-4 analogues
have been developed15−18 as VDAs in the past decade, and
roles in many aspects of cellular structure and function. Inves-
some of them have entered clinical trials.19−26 (Figure 1).
tigations into the polymerization dynamics that regulate micro-
The early phase clinical trials in many solid tumors have
tubule efficacy and in turn cellular replication may prove useful
in the development of anticancer therapeutics.1 This is one of
demonstrated that these CA-4 analogues have promising
therapeutic benefits.27,28 However, many of them were also
the reasons why microtubules are an attractive molecular target
hampered by dose-limiting toxicities21 or cumulative toxic-
for anticancer agents. Compounds target microtubules bind at
ities.20 Some of these toxicities came from the effect on other
tissues of these drugs (lack of specificity of tumor-related
vasculature)29 or from the systemic effects of cytokines and
other factors produced in compensatory response of tumors.30
Currently, CA4P in combination with antiangiogenic drugs,
metronomic chemotherapy, or radiotherapy has been inves-
tigated to improve the therapeutic index in preclinical and
clinical studies.31−34 Furthermore, developing novel CA-4 analo-
gues of improved specificity is another important approach to
reduce their toxicity.35−38
three distinct binding sites:2 the taxane site for microtubule-
stabilizing agents,3,4 the vinca site,5 and the colchicine site6,7 for
microtubule-destabilizing agents. The taxanes and vinca
alkaloids have been successfully used in clinical oncology;8−10
however, none of the colchicine site inhibitors (CSIs) have
been approved in clinic as antitumor agents.
The first CSI colchicine, which inhibits cancer cell prolifera-
tion powerfully, has limited its applications in clinic as anti-
tumor agent because of its narrow therapeutic index.11 Recent
studies show that another CSI combretastatin A-4 (CA-4,
Figure 1) with strong cytotoxicities has activity as vascular
It is well-known that CSIs have three important pharmaco-
phore components, a linking bridge and two hydrophobic rings
(rings A and B, Figure 1), and the appropriate dihedral angle
and cis-configuration of the two rings are important. As the two
hydrophobic rings of the CA-4 analogues are essential to their
activities,39−42 a large number of modifications of CA-4 focused
on the linking bridge.43−48 There also some modifications
focused on combining the linking bridge with the B ring, which
provided a potential advantage in promoting the acitivities,49−53
enhancing the tumor selectivity, and minimizing the
toxicity.36−38,54 Therefore, we designed a new CA-4 analogue
with the 1-benzylidene-3,4-dihydronaphthalen-2-one skeleton,
in which the relatively flexible six-membered ring connects the
Figure 1. Structures of CA-4 and its analogues that entered clinical
trials.
disrupting agents (VDAs) targeting already established vascula-
ture of solid tumors, causing rapid and catastrophic vascular
Received: December 31, 2011
Published: June 7, 2012
© 2012 American Chemical Society
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linking bridge and B ring. It provided proper restriction to the
dihedral angle of the two aromatic rings, and the carbonyl group
near the linking bridge can improve its solubility and may be
favorable for activity because of its polar interactions with the
β-Ala250−Leu255 loop at the tubulin colchicine site.55−57
In this study, a series of 1-benzylidene-3,4-dihydronaphthalen-
2-one derivatives were synthesized, and their cytotoxicity levels
were evaluated. The effects on tubulin polymerization and the
tumor cell cycle distribution of selected compounds were inves-
tigated to determine their exact mechanism, and their modes of
binding to tubulin were studied by molecular docking. The most
promising compound was further tested for antitumor activity
and toxicity in vivo.
compounds could exist as either E or Z isomers because of the
presence of the exocyclic double bond, the synthesis gave rise
to a single (predominant) isomer. To distinguish the con-
figuration (E or Z) of these compounds, we focused on the
chemical shifts of the H-2′ or H-6′ protons on the benzylidene
A ring. In the literature,59 deshielding by the carbonyl group on
the naphthalen-2-one would make chemical shifts of the H-2′ or
H-6′ protons downfield from 7.45−7.84 ppm (E isomer) to
7.85−8.53 ppm (Z isomer). All the chemical shifts of the
aromatic protons were below 7.84 ppm, consistent with the
literature and indicating that the products were E isomers. To
unequivocally confirm the configuration of these 1-benzylidene-
3,4-dihydronaphthalen-2-one analogues, compound 22b was
subjected to single-crystal X-ray analysis, as shown in Figure 2A,
which also verified the E configuration.
X-ray crystal analysis of one compound indicated a low-
energy conformation. In order to determine whether the
1-benzylidene-3,4-dihydronaphthalen-2-one skeleton could
provide a proper restriction to the dihedral angle of the two
aromatic rings, the X-ray crystal structure of compound 22b
was superimposed onto the binding conformation to tubulin of
CA-4. As shown in Figure 2B, the conformation of compound
22b fits that of CA-4 very well. The 1-benzylidene-3,4-
dihydronaphthalen-2-one, via its flexible nonplanar structure
incorporating an olefin linking bridge, restricted the appropriate
dihedral angle of the two rings in a proper range.
RESULTS AND DISCUSSION
■
Chemistry. The general route for the synthesis of the target
1-benzylidene-3,4-dihydronaphthalen-2-one derivatives is de-
picted in Scheme 1. The appropriate dimethoxynaphthalenes
a
Scheme 1. Synthesis of the Target Compounds
Biological Activity. The in vitro antitumor activity of all
the synthesized 1-benzylidene-3,4-dihydronaphthalen-2-one
analogues was tested in three human tumor cell lines by
MTT assay: the CEM human leukemia, HCT-116 human
colon cancer, and MDA-MB-435 human breast carcinoma cell
lines. These cell lines were selected from the solid tumors19,32
and non-solid tumors60 used in preclinical and clinical research
of CA-4 analogues. CA-4 was used as a positive control. The
results showed that all of the target compounds exhibited
anticancer activity (Table 1). Compound 22b displayed the
strongest antiproliferative activity against CEM (IC50 = 1 nM),
a
Reagents: (i) (CH3)2SO2, NaOH; (ii) Na, EtOH; (iii) substituted
benzylidene, AcOH/piperidine, CH2Cl2.
were prepared by methylation with dimethyl sulfate. The
intermediates 2a−c were chemoselectively reduced at the
β-position of the naphthalene ring using sodium in refluxing
ethanol to yield derivatives 3a−c. The Knoevenael reaction
with the appropriate benzylidene catalyzed by piperidine and
acetic acid at room temperature furnished 1-benzylidene-3,4-
dihydronaphthalen-2-one derivatives.58 The structures of 60
targeting compounds are listed in Scheme 1.
MDA-MBA-435 (IC50 = 1 nM), and HCT-116 cells (IC50
=
0.1 μM). The compounds’ cytotoxicities against CEM and
MDA-MBA-435 cells were compared to those of CA-4. In a
follow-up assay, compound 22b also showed potent cytotox-
icity against other cell lines of these three tumors: the K562
human leukemia (IC50 = 1 nM), HT-29 human colon cancer
The steric hindrance of the carbonyl group on naphthalen-
2-one was found to favor the E isomer. Though the final
Figure 2. X-ray structure of compound 22b: (A) ORTEP drawing of compound 22b; (B) superposition of 22b (green) with the docking modes of
CA4 (gray) bound to the colchicine of tubulin.
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(IC50 = 0.01 μM), and ZR-75-30 human breast carcinoma cell
lines (IC50 = 0.01 μM).
CA-4 was also examined for comparative purposes. The results
showed that compound 22b, which had shown the strongest
cytotoxicity, has the strongest antitubulin activity (IC50 of
3.93 μM compared to 1.77 μM for CA-4). This trend for the
inhibition of tubulin polymerization of the compounds was in
good qualitative agreement with their cytotoxic SAR.
Compound 22b (6-methoxy on the B ring), which has the
same 3,4,5-trimethoxy group on the A ring, was found to be
more potent than 22a (5-methoxy) and 22c (7-methoxy)
against cancer cell lines. It was also more active against tubulin
polymerization. This is consistent with the conclusion that
methoxy substituted at the C-6 position of 3,4-dihydronaph-
thalen-2-one is more effective than at C-5 or C-7. A gradual
decrease in antitubulin activity was observed as we moved from
compounds 22b, 20b, 21b to 5b. This was also consistent with
their antiproliferative tendencies, which appear to be based on
the number of methoxy groups on the A ring. In addition, the
antitubulin abilities (23b vs 5b) also illustrated that a methoxy
group at the C-2 position on the A ring had a negative effect.
This was consistent with the observation of cytotoxicities. On
the basis of this correlation between the antitubulin and
anticancer activities, we concluded that the antiproliferative
effects of these compounds were mediated by direct interaction
with tubulin.
The hydrophobic B ring was fundamental for antiprolifer-
ative activity.40,61 The position of the methoxy substituent on
the 3,4-dihydronaphthalen-2-one moiety (B ring) had a critical
influence on their cytotoxicities. The SAR information
indicated that the methoxy group located at the C-6 position
exhibited the best activity; shifting it to the C-5 or C-7 position
resulted in moderate activity. Most of the 6-methoxy
substituted compounds were 2- to 60- fold more potent than
5- or 7-methoxy counterparts against all the test cancer cells.
Notably, the most active compound, 22b, caused a distinct
increase in cytotoxicity by 2−3 orders of magnitude (22b vs
22a, 22c). The 6-methoxy group on the tetralone ring in
1-benzylidene-3,4-dihydronaphthalen-2-ones may mimic the
para-methoxy on the B ring of CA-4, exerting maximum
activity.
In the series of 6-methoxy-3,4-dihydronaphthalen-2-one
analogues, compound 22b, which has a 3,4,5- trimethoxy
group on its A ring, showed the most pronounced
antiproliferative activity. To determine the role of SAR
substitutions on the 1-benzylidene ring (A ring of CA-4), we
introduced various groups to the A ring. As shown in Table 1,
compounds with a methoxy group were generally more
cytotoxic than the other moieties. Neither replacement with a
smaller group (5b vs 6b) nor replacement with a larger (5b vs
7b, 17b) caused any decrease in potency. Replacement with
more polar groups (5b vs 8b, 9b, 10b) resulted in a slight loss
of cytotoxic activity.
The number and location of methoxy substituted on A ring
played a profound role on antiproliferative activity. A
comparison between the antiproliferative activities of com-
pounds 22b, 20b, 21b, and 5b illustrated the cytotoxic SAR
of the number of methoxy groups substituted on the A ring
(3 > 2 > 1). However, introducing a methoxy group at the C-2
position on the A ring showed a deleterious effect on activity.
It was supported by compound 23b (2,3,4- trimethoxy), which
was around 5- to 10-fold less active than the dimethoxy
substituent (20b and 21b) and about 2- to 8-fold less potent
than the methoxy substituent (5b). Replacing any methoxy on
compound 20b with a hydroxyl moiety (resulting in
compounds 18b and 19b) was found to cause a 3- to 80-fold
decrease in antiproliferative activity against all cell lines, further
indicating that the presence of polar substituents on the A ring
is unfavorable to potency.
Analysis of Cell Cycle Effects. Because the inhibition of
tubulin polymerization is often implicated in G2/M-phase cell
cycle arrest in various cancer cell lines, the effects of different
concentrations of compound 22b on cell cycle progression
were examined with HCT-116 cells. After 24 h of exposure,
compound 22b was found to cause an obvious increase in the
number cells in the G2/M phase with a concomitant decrease
of cells in the G1 and S phases. This effect appeared to be dose
dependent. As shown in Figure 3, lower concentrations of 22b
To determine whether these compounds exert their activities
by direct interaction with microtubules, selected compounds
(5b, 20b, 21b, 22a, 22b, 22c, and 23b) were examined for
their effects on the in vitro polymerization of tubulin (Table 2).
Figure 3. Cell cycle distribution of human cancer HCT-116 cells
treated for 24 h with different amounts of 22b.
Table 2. In Vitro Antitubulin Effects of the Target
Compounds
(0.2 μM) induced a slight alteration (17% of cells were in
the G2/M phase, compared to 13% of untreated cells) in the
distribution of HCT-116 cells throughout the cell cycle, whereas
higher concentrations (2 μM) induced a massive accumula-
tion (74%).
Molecular Modeling Studies. To make sense of the
cytotoxic and antitubulin data observed, molecular docking
simulations of the relative compounds to tubulin were carried
out. The X-ray crystal structure of the DAMA−colchicine−
tubulin complex (PDB code 1SA0) was used as the tubulin
compd
inhibition of tubulin assembly, IC50 SD (μM)
22a
22b
22c
20b
21b
5b
18.68 2.32
3.93 0.40
9.63 1.1
6.42 0.55
6.88 1.03
25.82 2.96
25.78 2.29
1.77 0.42
23b
CA-4
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Figure 4. Predicted binding modes with DAMA-colchicine at the β-tubulin binding site: (A) CA-4 (green) and 22b (red); (B) 22b (red) and 23b
(blue). P1 and P2 are two hydrophobic pockets in the interface between α- and β-tubulin.
protein template. The result shows that most of the compounds
bound to the colchicine binding site of tubulin in the same
orientation with CA-4. Compound 22b bound to tubulin
nicely, and the binding mode is shown in Figure 4A. The
trimethoxyphenyl moiety can foster van der Waals interactions
with the hydrophobic P1 pocket bounded by Leu248, Ala316,
Val318, Lys352, and Ile378 of β-tubulin, while the tetralone
ring can foster van der Waals interactions with the hydrophobic
P2 pocket consisting of Thr179, Val181 of α-tubulin and
Asn258, Met259, Lys352 of β-tubulin. Two methoxy O atoms
on the A ring form a hydrogen bond with the thiol group of
Cys241 of β-tubulin. The carbonyl group on tetralone remains
in proximity to the polar region L (Figure 4) with large
flexibility (Leu248-Lys254 of β-tubulin), which has the
possibility to form hydrogen bonds directly or through the
structured water molecules.57,62
and the other doses for CA-4 and compound 22b did not cause
any mouse to die. The body weight change of the mice over the
course of the experiment is shown in Figure 5. Compared to
Figure 5. Acute toxicity testing for compound 22b and CA-4.
The methoxy on the B ring is placed in the hydrophobic P2
pocket and enhances the van der Waals interactions with it.
However, the methoxy at the C-6 position was buried deeper in
the pocket than C-5 or C-7 position when binding, leading to
compounds bearing this group to have relatively higher binding
abilities, which is consistent with their biological activity levels
observed. In addition, the methoxy at C-3, C-4, and C-5
positions of the A ring forms van der Waals interactions well
with the hydrophobic P1 pocket. This may be the reason why
adding methoxy groups to these positions can enhance their
cytotoxic activity, and the presence of polar substituents is
unfavorable to activity. The methoxy is the group with optimal
volume for interaction with this pocket, which can explain why
replacement with neither a smaller group nor a larger group is
unfavorable to activity. However, introducing a methoxy group
at the C-2 position on the A ring showed a dramatic loss in
activity, which can be rationalized by the docking result of
compound 23b compared to compound 22b (Figure 4B). The
A ring cannot occupy the P1 pocket well because of steric
hindrance with tubulin of the C-2 position methoxy.
the control vehicle-treated mice, compound 22b, even at a dose
of 600 mg/kg, did not cause significant body weight loss, which
is indicative of negligible systemic toxicity over 10 days.
However, significant body weight loss was observed at 50 mg/kg
CA-4, suggesting some systemic toxicity.
Guided by the preliminary toxicity experiment, the doses
(100, 150, 300 mg/kg for compound 22b; 30 and 50 mg/kg for
CA-4) were chosen to evaluate their in vivo antitumor activity.
Human colon carcinoma xenografts were established by
subcutaneous implantation of HT-29 cells (5 × 106) on the
right flanks of BALB/C nude mice. Once the HT-29 xenografts
reached a size of around 100 mm3, mice were randomly
assigned into control group (12 mice) and intervention groups
(6 mice per group). Antitumor activities of compound 22b and
CA-4 (ip once a day) were studied with cisplatin (ip the first 2
days) as a positive control. The results (Figure 6 and Table 3)
showed that compound 22b at 100, 150, and 300 mg/kg dose-
dependently decreased tumor volumes on day 21 (T/C = 52%,
45%, and 34%, respectively), while the T/C of CA-4 at
50 mg/kg was 47%. Compared to the control vehicle-treated
mice, compound 22b at diverse doses did not cause obvious
body weight loss, and the vital organs (kidney, liver, and
spleen) examined after euthanization at the end of the experi-
ment appear the same in terms of color, weight, and size,
indicating negligible toxicity to the mice. However, obvious
body weight loss was observed at every dose of CA-4, and
lost weight of the vital organs was observed at 50 mg/kg CA-4.
In Vivo Antitumor Activity. Compound 22b and CA-4
were preliminarily evaluated for toxicity against male ICR mice,
using ip administration once on day 1. Mice were randomly
divided into the control group and intervention groups (150,
300, 600 mg/kg for compound 22b; 50 and 100 mg/kg for
CA-4) with 20 mice in each group and half male and half
female. The dose 100 mg/kg for CA-4 caused one mouse
(1/20) to die on day 2 and another two mice to die on day 5,
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Figure 6. Inhibition of human xenograft growth in vivo by compound 22b and CA-4. HT-29 tumor-bearing nude mice were administered vehicle
alone or 100, 150, 300 mg/kg compound 22b or 30, 50 mg/kg CA-4 intraperitoneally once a day. The figure shows the tumor volume of 22b (A)
and CA-4 (B) recorded at the indicated days after treatments. Data are expressed as mean SEM of tumor volume at each time point.
a
Table 3. Blood Analysis after in Vivo Antitumor Activity against Human Colon Carcinoma Model
tumor volume,
mean SD
(mm3)
body wt
change,
mean (g)
compd
(mg/kg)
mice toxic
T/C
(%)
WBC
PLT
(n)
death
(×103 mm−3
)
LY (×103 mm−3
)
(×103 mm−3
)
ALT (IU/L)
ALP (IU/L)
control
12
6
0/12
0/6
0/6
0/6
0/6
0/6
0/6
1702 114
888 126**
772 149**
595 73**
905 98**
799 98**
493 41**
100
52
45
34
53
47
29
2.7
2.3
3
25.38 0.22
15.88 0.41
1509 34
28 0.4
107.6 0.8
112 1.3*
116.3 0.8*
107.6 0.8
105.3 1.1
149.3 1.1**
127.6 2.8*
22b (100)
22b (150)
22b (300)
CA-4 (30)
CA-4 (50)
cisplatin (7)
24.42 0.27**
20.18 0.10**
19.96 0.49**
19.34 0.38**
12.09 0.20**
7.34 0.24**
11.08 0.27**
10.03 0.85*
8.87 0.61**
10.62 2.01
1440
4
24 0.6*
28 0.6
6
1375 21
1240 34*
1923 38*
2206 38**
902 14**
6
2.6
1.7
1.8
1.1
26 0.6
6
25 0.6*
66.3 0.4**
29.6 1.1
6
4.14 0.04**
4.11 0.14**
6
a
WBC = white blood cell. LY = lymphocyte. PLT = platelet. ALT = alanine transaminase. ALP = alkaline phosphatase. Data are expressed as the
mean SEM. (∗) P < 0.05, (∗∗) P < 0.01 vs control.
potent compound, 22b, became arrested in the G2/M phases
of the cell cycle. These results showed that the antiproliferative
effects of these compounds were mediated by direct interaction
with tubulin. Then molecular docking simulations of these
compounds to tubulin were carried out. The results show that
they are nicely bound to the colchicine binding site of tubulin
with a very similar binding mode of CA-4 and can rationalize
the experimental SAR well. The antitumor activity in vivo of
compound 22b was tested, and the results showed that
compound 22b could inhibit the tumor growth in colon nude
mouse xenograft tumor model (HT-29 cells) significantly and
seemed safer than CA-4 when achieving a similar tumor
suppression. This study provides a new molecular scaffold for
the further development of antitumor agents that target tubulin.
The biochemical parameters (Table 3) examined at the end of
the experiment showed that, after compound treatment, white
blood cells and lymphocytes may decrease and alanine
transaminase and alkaline phosphatase may increase com-
pared to the vehicle control, which indicated some toxicity to
liver and bone marrow. However, at a dose (compound 22b,
150 mg/kg; CA-4, 50 mg/kg) achieving a similar T/C ratio, the
change of the biochemical parameters of compound 22b was
less obvious than that of CA-4. Even at a greater dose achieving
a larger T/C ratio (300 mg/kg, T/C = 34%), compound 22b
still displayed this advantage.
All these results showed that this CA-4 analogue compound
22b could inhibit tumor growth significantly and seemed safer
than CA-4 when achieving a similar tumor suppression, which
is probably attributed to its negligible effect on normal tissues
and good specificity of tumor-related vasculature. The exact
mechanism still needs further research.
EXPERIMENTAL SECTION
■
Chemistry. General Methods. Melting points were measured on
an electrically heated RK-Z melting point apparatus and are
uncorrected. Infrared (IR) spectra were recorded on a PE Spectrum
One FI-IR spectrometer as KBr pellets. 1H NMR and 13C NMR
spectra were recorded on a Bruker AC-300P spectrometer (Bruker
Company, Germany), using TMS as an internal standard and CDCl3
or DMSO-d6 as solvents. Chemical shifts are given in ppm (δ), and the
spectral data are consistent with the assigned structures. The mass
spectra were recorded on a Micromass Qtof-Micro LC−MS
instrument. Crystal structure was determined on a Bruker SMART
CCD (Bruker Company, Germany). Silica gel thin-layer chromatog-
raphy was performed on precoated plates GF-254. Silica gel column
chromatography was performed with silica gel 60 G. All compounds
were routinely checked by TLC by using silica gel plates GF-254. All
solvents and reagents were analytically pure and, when necessary, were
purified and dried by standard protocols. All starting materials were
commercially available unless otherwise indicated. Yields of purified
products were not optimized. The purity of each compound (>95%) was
determined on an Agilent 1100 series LC system (column, ZORBAX
CONCLUSION
■
A series of 1-benzylidene-3,4-dihydronaphthalen-2-one deriva-
tives were designed and synthesized, and their biological
activities were evaluated in vitro and in vivo. The results
showed all the title compounds to exhibit inhibitory activity
against the three human cancer cell lines. Preliminary
structure−activity relationship studies indicated that substitu-
tion at the C-6 position of the B ring of the title molecule was
beneficial to cytotoxic activity. Among all analogues synthesized
in this study, (E)-1-(3,4,5-trimethoxybenzylidene)-6-methoxy-
3,4-dihydronaphthalen-2(1H)-one (22b) was the most potent
inhibitor of human tumor cell growth (IC50 of 1 nM against
several human tumor cell lines) and tubulin polymerization
(IC50 of 3.93 μM). A flow cytometric study showed that a
significant percentage of HCT-116 cells treated with the most
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1
Eclipse XDB C8, 4.6 mm × 150 mm, 5 μm; mobile phase, methanol
(80%)/H2O; flow rate, 1.0 mL/min; UV wavelength, absorbance at
254 nm; temperature, ambient; injection volume, 20 μL).
697, 662, 564, 537, 471, 441. H NMR (300 MHz, CDCl3) δ 7.71 (s,
1H), 7.30−7.36 (m, 2H), 7.23−7.27 (m, 3H), 6.98 (d, J = 7.8 Hz,
1H), 6.92 (d, J = 7.8 Hz, 1H), 6.79 (d, J = 7.8 Hz, 1H), 3.88 (s, 3H),
3.10 (t, J = 6.3 Hz, 2H), 2.58 (t, J = 6.3 Hz, 2H); 13C NMR (300
MHz, CDCl3) δ 202.09, 156.19, 135.44, 135.29, 134.00, 133.91,
129.65, 128.85, 128.28, 127.02, 126.54, 121.45, 109.69, 55.56, 36.55,
19.33; HRMS (ES+) m/z found 264.1151; C18H16O2 (M+) requires
264.1150.
General Method for the Synthesis of Methoxy-2-tetralones
3a−c. The method to synthesize 5-methoxy-2-tetralone (3a) is
described. To a 1 L round-bottom flask fitted with mechanical stirrer,
1,6-dimethoxynaphthalene (20.0 g, 0.11 mol) was added to the
refluxing anhydrous ethanol (200 mL). Sodium (19 g, 0.83 mol), cut
into small pieces, was added as rapidly as possible to the solution.
Refluxing was continued until all sodium disappeared. The reaction
mixture was cooled to 10 °C, and then 2 N hydrochloric acid (about
330 mL) was added dropwise until the pH was changed to 3. The
reaction mixture was extracted with acetic ether (50 mL × 3). The
ethyl acetate layers were combined and washed with saturated brine
solution (50 mL × 3), dried over anhydrous sodium sulfate, and
filtrated, and the solvent was evaporated. The residual oil was purified
by distillation under reduced pressure to yield 11.8 g (63%) of 3a as
yellow oil, which solidified under room temperature: bp 160−165 °C
(10 mmHg). Recrystallization from petroleum ether (bp 60−90 °C)
gave 3a as a white needle: mp 38−40 °C
(E)-1-(4-Methoxybenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (5a). Yield 55%, yellow crystal. Mp: 106−108 °C.
HPLC: 96.6%. IR (KBr) ν (cm−1): 3075, 2994, 2953, 2906, 2842,
1682, 1606, 1588, 1510, 1490, 1462, 1442, 1409, 1364, 1295, 1251,
1208, 1171, 1136, 1110, 1028, 946, 904, 871, 826, 720, 590, 527, 502.
1H NMR (300 MHz, CDCl3) δ 7.65 (s, 1H), 7.46 (d, J = 7.2 Hz, 2H),
7.18 (d, J = 8.1 Hz, 1H), 6.99 (s, 1H), 6.81 (d, J = 7.8 Hz, 2H), 6.76
(s, 1H), 3.82 (s, 3H), 3.55 (s, 3H), 2.96 (s, 2H), 2.60 (s, 2H); 13C
NMR (300 MHz, CDCl3) δ 201.69, 160.38, 157.52, 135.30, 133.76,
131.93, 131.63, 130.70, 128.81, 127.19, 114.83, 113.78, 112.93, 55.25,
55.14, 37.36, 26.92; HRMS (ES+) m/z found 294.1255; C19H18O3
(M+) requires 294.1256.
(E)-1-(4-Methoxybenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (5b). Yield 52%, yellow crystal. Mp: 118−120 °C.
HPLC: 97.1%. 1H NMR (300 MHz, CDCl3) δ 7.62 (s, 1H), 7.47 (dd,
J = 8.4, 2.4 Hz, 1H), 7.38 (d, J = 8.1 Hz, 2H), 6.87 (d, J = 8.1 Hz, 2H),
6.80 (d, J = 2.7 Hz, 1H), 6.60 (dd, J = 8.7, 2.1 Hz, 1H), 3.88 (s, 3H),
3.83 (s, 3H), 3.00 (t, J = 6.6 Hz, 2H), 2.61 (t, J = 6.6 Hz, 2H); HRMS
(ES+) m/z found 294.1257; C19H18O3 (M+) requires 294.1256.
(E)-1-(4-Methoxybenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (5c). Yield 60%, yellow crystal. Mp: 128−130 °C.
HPLC: 95.8%. IR (KBr) ν (cm−1): 3091, 3072, 3002, 2955, 2932,
2906, 2882, 2835, 1687, 1604, 1568, 1507, 1466, 1438, 1367, 1340,
1305, 1255, 1168, 1140, 1110, 1067, 1031, 964, 911, 825, 798, 779,
Similarly, 3b and 3c were synthesized from the appropriate dimeth-
oxynaphthalenes. Compound 3b: mp 36−38 °C (lit. mp 36 °C). Com-
pound 3c: mp 28−30 °C (lit. mp 27−28 °C)
General Method for the Synthesis of (E)-1-Benzylideneme-
thoxy-2-tetralone Analogues (4−23). (E)-1-(3,4,5-Trimethoxy-
benzylidene)-6-methoxy-3,4-dihydronaphthalen-2(1H)-one
(22b). A solution of compound 3b (1.76 g, 10 mmol) and 3,4,
5-trimethoxybenzaldehyde (1.96 g, 10 mmol) in dichloromethane
(30 mL) was stirred under room temperature for 24 h. The reaction
mixture was washed with water, saturated brine solution. The com-
bined organic layers were dried over anhydrous sodium sulfate, filtered,
evaporated in vacuo, and purified by column chromatography on silica
gel (eluent, petroleum ether/acetic ether, 50:1 to 10:1 v/v) or
recrystallization to afford the pure compound 22b as a yellow crytstal.
1
732, 517, 428. H NMR (300 MHz, CDCl3) δ 7.64 (s, 1H), 7.40 (d,
J = 8.4 Hz, 2H), 6.98−7.07 (m, 2H), 6.77 (d, J = 8.7 Hz, 2H), 6.76 (s,
1H), 3.88 (s, 3H), 3.85 (s, 3H), 3.07 (t, J = 6.3 Hz, 2H), 2.56 (t, J =
6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 202.17, 160.33, 156.20,
135.40, 134.44, 132.05, 131.61, 127.41, 126.96, 126.48, 121.17, 113.72,
109.46, 55.55, 55.23, 36.64, 19.34; HRMS (ES+) m/z found 294.1254;
C19H18O3 (M+) requires 294.1256.
1
Yield 47%. Mp: 102−104 °C. HPLC: 99.7%. H NMR (300 MHz,
CDCl3) δ 7.49 (s, 1H), 7.44 (d, J = 8.6 Hz, 1H), 6.80 (d, J = 2.2 Hz,
1H), 6.72 (s, 2H), 6.64 (dd, J = 8.6, 2.2 Hz, 1H), 3.85 (s, 6H), 3.71
(s, 6H), 3.01 (t, J = 6.4 Hz, 2H), 2.62 (t, J = 6.4 Hz, 2H); 13C NMR
(300 MHz, CDCl3) δ 201.78, 159.42, 152.91, 140.23, 138.68, 133.21,
132.59, 130.60, 130.46, 124.86, 112.73, 111.81, 106.86, 60.89, 55.93,
55.25, 36.98, 28.05; HRMS (ES+) m/z found 354.1466; C21H22O5(M+)
requires 354.1467.
(E)-1-(4-Methylbenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (6a). Yield 40%, yellow crystal. Mp: 104−106 °C.
1
HPLC: 96.2%. H NMR (300 MHz, CDCl3) δ 7.68 (s, 1H), 7.36 (d,
The synthetic methods for the following compounds were similar to
J = 8.1 Hz, 2H), 7.18 (d, J = 8.4 Hz, 1H), 7.08 (d, J = 8.1 Hz, 2H),
6.92 (s, 1H), 6.77 (dd, J = 8.4, 2.7 Hz, 1H), 6.83 (dd, J = 8.4 Hz, J =
2.2 Hz, 1H), 3.52 (s, 3H), 2.98 (t, J = 6.6 Hz, 2H), 2.61 (t, J = 6.6 Hz,
2H), 2.34 (s, 3H); 13C NMR (300 MHz, CDCl3) δ 201.63, 157.49,
139.26, 135.56, 133.57, 133.03, 132.08, 130.68, 129.70, 129.06, 128.76,
114.96, 113.17, 55.06, 37.31, 26.89, 21.38; HRMS (ES+) m/z found
278.1330; C19H18O2(M+) requires 278.1307.
(E)-1-(4-Methylbenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (6b). Yield 46%, yellow crystal. Mp: 120−122 °C.
HPLC: 96.8%. 1H NMR (300 MHz, CDCl3) δ 7.58 (s, 1H), 7.35 (dd,
J = 8.1, 2.7 Hz, 3H), 7.07 (d, J = 8.1 Hz, 2H), 6.80 (d, J = 2.7 Hz, 1H),
6.60 (dd, J = 8.7, 2.7 Hz, 1H), 3.83 (s, 3H), 3.00 (t, J = 6.3 Hz, 2H),
2.62 (t, J = 6.3 Hz, 2H), 2.34 (s, 3H); 13C NMR (300 MHz, CDCl3) δ
201.88, 159.34, 140.05, 138.94, 133.57, 132.53, 130.29, 129.52, 129.11,
125.23, 112.76, 112.03, 55.23, 37.10, 28.10, 21.41; HRMS (ES+) m/z
found 278.1307; C19H18O2(M+) requires 278.1307.
the synthesis of compound 22b.
(E)-1-Benzylidene-5-methoxy-3,4-dihydronaphthalen-2(1H)-
one (4a). Yield 58%, yellow crystal. Mp: 110−112 °C. HPLC: 96.2%.
IR (KBr) ν (cm−1): 3355, 3072, 3020, 2995, 2958, 2904, 2831, 1688,
1606, 1569, 1488, 1439, 1403, 1359, 1303, 1278, 1241, 1190, 1167,
1096, 1038, 991, 934, 899, 874, 850, 808, 756, 710, 690, 586, 553, 504,
462, 425. 1H NMR (300 MHz, CDCl3) δ 7.71 (s, 1H), 7.41−7.44 (m,
2H), 7.24−7.29 (m, 3H), 7.17 (d, J = 8.4 Hz, 1H), 6.83 (s, 1H), 6.77
(dd, J = 8.4, 2.4 Hz, 1H), 3.45 (s, 3H), 2.99 (t, J = 6.3 Hz, 2H), 2.62 (t,
J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.50, 157.54,
135.37, 135.27, 133.84, 130.73, 129.56, 128.90, 128.87, 128.40, 115.33,
113.16, 55.00, 37.32, 26.90; HRMS (ES+) m/z found 264.1152;
C18H16O2 (M+) requires 264.1150.
(E)-1-Benzylidene-6-methoxy-3,4-dihydronaphthalen-2(1H)-
one (4b). Yield 52%, yellow crystal. Mp: 105−107 °C. HPLC: 95.8%.
1H NMR (300 MHz, CDCl3) δ 7.60 (s, 1H), 7.40−7.47 (m, 2H),
(E)-1-(4-Methylbenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (6c). Yield 48%, yellow crystal. Mp: 160−162 °C.
HPLC: 97.9%. IR (KBr) ν (cm−1): 3092, 3022, 2959, 2889, 2855,
2835, 1690, 1608, 1594, 1573, 1503, 1474, 1438, 1400, 1365, 1340,
1303, 1264, 1249, 1183, 1163, 1141, 1109, 1068, 1020, 986, 965, 910,
7.24−7.29 (m, 4H), 6.80 (d, J = 2.4 Hz, 1H), 6.57 (dd, J = 8.7, 2.4 Hz,
1H), 3.83 (s, 3H), 3.02 (t, J = 6.6 Hz, 2H), 2.63 (t, J = 6.6 Hz, 2H);
13C NMR (300 MHz, CDCl3) δ 201.78, 159.40, 140.07, 135.55,
133.31, 133.24, 130.38, 129.40, 128.60, 128.34, 124.94, 112.78, 112.03,
55.20, 37.01, 28.04; HRMS (ES+) m/z found 264.1166; C18H16O2
(M+) requires 264.1150.
1
887, 844, 813, 789, 780, 731, 693, 669, 573, 499, 472, 430. H NMR
(300 MHz, CDCl3) δ 7.67 (s, 1H), 7.32 (d, J = 7.8 Hz, 2H), 7.06 (d,
J = 8.1 Hz, 2H), 6.99 (d, J = 4.5 Hz, 2H), 6.78 (t, J = 4.5 Hz, 1H), 3.89
(s, 3H), 3.08 (t, J = 6.6 Hz, 2H), 2.57 (t, J = 6.6 Hz, 2H), 2.34 (s, 3H);
13C NMR (300 MHz, CDCl3) δ 202.19, 156.16, 139.22, 135.65,
134.25, 133.12, 132.22, 129.78, 129.02, 126.95, 126.50, 121.35, 109.54,
(E)-1-Benzylidene-7-methoxy-3,4-dihydronaphthalen-2(1H)-
one (4c). Yield 58%, yellow crystal. Mp: 118−120 °C. HPLC: 97.4%.
IR (KBr) ν (cm−1): 3077, 3043, 3021, 2996, 2966, 2933, 2873, 2837,
2795, 1686, 1599, 1574, 1473, 1442, 1408, 1365, 1342, 1301, 1272,
1253, 1181, 1159, 1138, 1067, 1020, 962, 929, 910, 841, 783, 756, 732,
5726
dx.doi.org/10.1021/jm300596s | J. Med. Chem. 2012, 55, 5720−5733

Journal of Medicinal Chemistry
Article
55.55, 36.60, 21.43, 19.33; HRMS (ES+) m/z found 278.1306;
C19H18O2(M+) requires 278.1307.
498, 441; 1H NMR (300 MHz, CDCl3) δ 8.15 (d, J = 9 Hz, 2H), 7.65
(s, 1H), 7.56 (d, J = 8.4 Hz, 2H), 7.27 (s, 1H), 7.24 (d, J = 9 Hz, 1H),
6.83 (dd, J = 8.4, 2.2 Hz, 1H), 3.51 (s, 3H), 3.03 (t, J = 6.3 Hz, 2H),
2.66 (t, J = 6.3 Hz, 2H); HRMS (ES+) m/z found 309.0998;
C18H15NO4 (M+) requires 309.1001.
(E)-1-(4-tert-Butylbenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (7a). Yield 53%, yellow crystal. Mp: 140−142 °C.
HPLC: 99.3%. IR (KBr) ν (cm−1): 3027, 2955, 2952, 2906, 2863,
2836, 1693, 1612, 1594, 1571, 1489, 1402, 1362, 1302, 1273, 1244,
1192, 1166, 1093, 1040, 993, 904, 828, 800, 709, 591, 549, 492, 420.
1H NMR (300 MHz, CDCl3) δ 7.70 (s, 1H), 7.43 (d, J = 8.1 Hz, 1H),
(E)-1-(4-Nitrobenzylidene)-6-methoxy-3,4-dihydronaphtha-
len-2(1H)-one (9b). Yield 50%, yellow crystal. Mp: 150−152 °C.
1
HPLC: 95.3%. H NMR (300 MHz, CDCl3) δ 7.95 (d, J = 8.7 Hz,
7.40 (d, J = 8.4 Hz, 2H), 7.31 (d, J = 8.4 Hz, 2H), 7.16 (d, J = 8.4 Hz,
1H), 6.89 (d, J = 2.7 Hz, 1H), 6.77 (dd, J = 8.4, 2.7 Hz, 1H), 3.47 (s,
3H), 2.98 (t, J = 6.6 Hz, 1H), 2.62 (t, J = 6.6 Hz, 1H), 1.31 (s, 9H);
13C NMR (300 MHz, CDCl3) δ 201.68, 157.45, 152.43, 135.52,
2H), 7.63 (s, 1H), 7.50 (d, J = 8.7 Hz, 2H), 7.24 (s, 1H), 7.18 (d, J =
2.4 Hz, 1H), 6.70 (dd, J = 8.4, 2.4 Hz, 1H), 3.51 (s, 3H), 3.03 (t, J =
6.3 Hz, 2H), 2.66 (t, J = 6.3 Hz, 2H); HRMS (ES+) m/z found
309.1002; C18H15NO4 (M+) requires 309.1001.
133.57, 133.29, 132.25, 130.70, 129.49, 128.79, 125.30, 115.39, 112.92,
54.94, 37.37, 34.76, 31.11, 26.92; HRMS (ES+) m/z found 320.1778;
C22H24O2 (M+) requires 320.1776.
(E)-1-(4-Nitrobenzylidene)-7-methoxy-3,4-dihydronaphtha-
len-2(1H)-one (9c). Yield 50%, yellow crystal. Mp: 156−158 °C.
HPLC: 96.4%. IR (KBr) ν (cm−1): 3112, 3082, 3029, 2989, 2966,
2931, 2906, 2859, 2833, 1697, 1594, 1516, 1471, 1434, 1405, 1342,
1296, 1247, 1176, 1133, 1108, 1066, 962, 914, 841, 787, 749, 688, 566,
(E)-1-(4-tert-Butylbenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (7b). Yield 56%, yellow crystal. Mp: 146−148 °C.
HPLC: 97.1%. IR (KBr) ν (cm−1): 3445, 3360, 3027, 2972, 2952,
2864, 1688, 1600, 1494, 1460, 1406, 1362, 1308, 1259, 1229, 1191,
1163, 1141, 1108, 1089, 1029, 912, 873, 843, 824, 714, 664, 621, 561,
1
478, 417. H NMR (300 MHz, CDCl3) δ 8.10 (d, J = 11.1 Hz, 2H),
7.62 (s, 1H), 7.48 (d, J = 11.1 Hz, 2H), 6.98 (t, J = 8.1 Hz, 1H), 6.82
(d, J = 7.5 Hz, 1H), 6.72 (d, J = 7.5 Hz, 1H), 3.88 (s, 3H), 3.11 (t, J =
6.6 Hz, 2H), 2.65 (t, J = 6.6 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ
201.47, 156.42, 147.34, 142.49, 136.73, 132.81, 131.99, 130.21, 127.44,
127.00, 123.58, 121.31, 110.48, 55.58, 36.17, 19.27; HRMS (ES+) m/z
found 309.1004; C18H15NO4 (M+) requires 309.1001.
(E)-1-(4-Trifluoromethylbenzylidene)-5-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (10a). Yield 46%, yellow crystal. Mp:
130−131 °C. HPLC: 96.8%. IR (KBr) ν (cm−1): 3063, 2994, 2965,
2944, 2907, 2847, 1699, 1614, 1599, 1568, 1489, 1412, 1356, 1322,
1247, 1165, 1129, 1104, 1063, 1042, 1015, 885, 833, 803, 703, 645,
602, 564. 1H NMR (300 MHz, CDCl3) δ 7.66 (s, 1H), 7.48−7.55 (m,
4H), 7.19 (d, J = 8.4 Hz, 1H), 6.78 (dd, J = 8.4, 1.8 Hz, 1H), 6.67 (d,
J = 2.1 Hz, 1H), 3.43 (s, 3H), 3.00 (t, J = 6.3 Hz, 2H), 2.63 (t, J = 6.3
Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.16, 157.63, 139.21,
135.55, 133.07, 132.55, 130.92, 129.68, 129.12, 125.33, 125.29, 115.57,
113.27, 54.89, 37.05, 26.77; HRMS (ES+) m/z found 332.1021;
C19H15F3O2 (M+) requires 332.1024.
1
470. H NMR (300 MHz, CDCl3) δ 7.58 (s, 1H), 7.40 (s, 3H), 7.28
(d, J = 6.6 Hz, 2H), 6.81 (s, 1H), 6.62 (d, J = 8.4 Hz, 1H), 3.84 (s,
3H), 3.00 (s, 2H), 2.61 (s, 2H); 13C NMR (300 MHz, CDCl3) δ
202.02, 159.33, 152.21, 140.01, 133.44, 132.57, 132.37, 130.30, 129.41,
125.28, 112.71, 112.06, 55.23, 37.06, 34.74, 31.14, 28.07; HRMS
(ES+) m/z found 320.1776; C22H24O2 (M+) requires 320.1776.
(E)-1-(4-tert-Butylbenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (7c). Yield 46%, yellow powder. Mp: 150−152 °C.
HPLC: 96.3%. IR (KBr) ν (cm−1): 3079, 3002, 2960, 2869, 2838,
1688, 1595, 1572, 1505, 1471, 1440, 1403, 1364, 1342, 1250, 1176,
1158, 1139, 1105, 1072, 1019, 962, 912, 827, 777, 727, 674, 576, 440.
1H NMR (300 MHz, CDCl3) δ 7.66 (s, 1H), 7.38 (d, J = 8.4 Hz, 2H),
7.27 (d, J = 8.4 Hz, 2H), 7.02 (d, J = 7.8 Hz, 2H), 6.80 (d, J = 7.5 Hz,
1H), 3.89 (s, 3H), 3.08 (t, J = 6.6 Hz, 2H), 2.57 (t, J = 6.6 Hz, 2H),
1.31 (s, 9H); 13C NMR (300 MHz, CDCl3) δ 202.33, 156.16, 152.48,
135.49, 134.31, 133.19, 132.12, 129.68, 126.94, 126.52, 125.20, 121.40,
109.60, 55.56, 36.58, 34.76, 31.15, 19.34; HRMS (ES+) m/z found
320.1779; C22H24O2 (M+) requires 320.1776.
(E)-1-(4-Hydroxybenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (8a). Yield 40%, yellow crystal. Mp: 150−152 °C.
HPLC: 95.4%. IR (KBr) ν (cm−1): 3377, 3021, 2995, 2940, 2908,
2834, 1679, 1612, 1586, 1512, 1488, 1432, 1403, 1367, 1303, 1275,
1249, 1191, 1167, 1100, 1039, 994, 961, 906, 831, 803, 706, 627, 587,
549, 525, 477, 446; 1H NMR (300 MHz, CDCl3) δ 7.62 (s, 1H), 7.35
(d, J = 8.4 Hz, 2H), 6.98−7.12 (m, 2H), 6.82 (d, J = 7.2 Hz, 2H),
6.70−6.76 (m, 1H), 5.50 (s, 1H), 3.82 (s, 3H), 2.99 (t, J = 6.3 Hz,
2H), 2.59 (t, J = 6.3 Hz, 2H); HRMS (ES+) m/z found 280.1098;
C18H16O3 (M+) requires 280.1099.
(E)-1-(4-Hydroxybenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (8b). Yield 42%, yellow crystal. Mp: 146−148 °C.
HPLC: 95.7%. 1H NMR (300 MHz, CDCl3) δ 7.60 (s, 1H), 7.41 (dd,
J = 8.4, 2.4 Hz, 1H), 7.30 (d, J = 8.4 Hz, 1H), 6.77 (dd, J = 8.1, 2.7 Hz,
2H), 6.70 (d, J = 2.7 Hz, 1H), 6.58 (dd, J = 8.7, 2.4 Hz, 2H), 5.62
(s, 1H) 3.88 (s, 3H), 3.83 (s, 3H), 3.00 (t, J = 6.6 Hz, 2H), 2.61 (t, J =
6.6 Hz, 2H); HRMS (ES+) m/z found 280.1086; C18H16O3 (M+)
requires 280.1099.
(E)-1-(4-Trifluoromethylbenzylidene)-6-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (10b). Yield 48%, yellow crystal. Mp:
1
123−125 °C. HPLC: 97.1%. H NMR (300 MHz, CDCl3) δ 7.54 (s,
1H), 7.51 (s, 4H), 7.15 (d, J = 8.7 Hz, 1H), 6.81 (d, J = 2.7 Hz, 1H),
6.58 (dd, J = 8.7, 2.7 Hz, 1H), 3.83 (s, 3H), 3.03 (t, J = 6.3 Hz, 2H),
2.65 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.02,
159.87, 140.41, 139.52, 134.96, 131.09, 130.49, 129.55, 125.37, 124.25,
113.17, 112.25, 55.29, 36.86, 28.00; HRMS (ES+) m/z found
332.1018; C19H15F3O2 (M+) requires 332.1024.
(E)-1-(4-Trifluoromethylbenzylidene)-7-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (10c). Yield 53%, yellow crystal. Mp:
1
123−125 °C. HPLC: 96.3%. H NMR (300 MHz, CDCl3) δ 7.63
(s, 1H), 7.62 (d, J = 8.4 Hz, 2H), 7.48 (d, J = 8.1 Hz, 2H), 7.09 (d, J =
8.4 Hz, 1H), 6.95 (s, 1H), 6.67 (d, J = 2.7 Hz, 1H), 3.62 (s, 3H), 3.05
(t, J = 6.3 Hz, 2H), 2.62 (t, J = 6.3 Hz, 2H); HRMS (ES+) m/z found
332.1028; C19H15F3O2 (M+) requires 332.1024.
(E)-1-(4-Bromobenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (11a). Yield 43%, yellow powder. Mp: 126−
1
128 °C. HPLC: 96.4%. H NMR (300 MHz, CDCl3) δ 7.55 (s, 1H),
7.42 (d, J = 8.7 Hz, 2H), 7.36 (s, 1H), 7.30 (s, 1H), 7.07 (d, J = 8.7
Hz, 2H), 7.00 (dd, J = 8.4, 2.2 Hz, 1H), 3.51 (s, 3H), 3.05 (t, J = 6.3
Hz, 2H), 2.59 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ
201.42, 157.64, 134.31, 134.10, 133.76, 132.95, 131.63, 131.15, 130.84,
129.03, 123.01, 115.24, 113.24, 55.13, 37.16, 26.84; HRMS (ES+) m/z
found 342.0257; C18H15BrO2 (M+) requires 342.0255.
(E)-1-(4-Hydroxybenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (8c). Yield 42%, yellow crystal. Mp: 153−155 °C.
1
HPLC: 99.1%. H NMR (300 MHz, CDCl3) δ 7.63 (s, 1H), 7.35 (d,
J = 8.4 Hz, 2H), 7.98−7.07 (m, 2H), 6.78 (d, J = 7.2 Hz, 1H), 6.73 (d,
J = 8.4 Hz, 2H), 5.58 (s, 1H), 3.88 (s, 3H), 3.06 (t, J = 6.3 Hz, 2H),
2.56 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 203.02,
156.91, 156.21, 135.85, 134.31, 131.90, 127.26, 126.89, 126.55, 121.18,
115.36, 109.52, 55.59, 36.70, 19.31; HRMS (ES+) m/z found
280.1119; C18H16O3 (M+) requires 280.1099.
(E)-1-(4-Bromobenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (11b). Yield 47%, yellow crystal. Mp: 126−
1
128 °C. HPLC: 97.1%. H NMR (300 MHz, CDCl3) δ 7.47 (s, 1H),
7.37 (d, J = 8.4 Hz, 2H), 7.27 (d, J = 8.4 Hz, 2H), 7.22 (d, J = 8.7 Hz,
1H), 6.79 (d, J = 2.4 Hz, 1H), 6.57 (dd, J = 8.7, 2.4 Hz, 1H), 3.83 (s,
3H), 2.99 (t, J = 6.3 Hz, 2H), 2.61 (t, J = 6.3 Hz, 2H); 13C NMR (300
MHz, CDCl3) δ 201.53, 159.62, 140.24, 134.52, 133.73, 131.69,
131.60, 130.95, 130.27, 124.52, 122.59, 113.03, 112.15, 55.24, 36.91,
(E)-1-(4-Nitrobenzylidene)-5-methoxy-3,4-dihydronaphtha-
len-2(1H)-one (9a). Yield 52%, yellow crystal. Mp: 131−133 °C.
HPLC: 95.2%. IR (KBr) ν (cm−1): 3097, 3021, 2998, 2969, 2943,
2907, 2835, 1698, 1608, 1520, 1485, 1462, 1343, 1305, 1282, 1247,
1209, 1165, 1107, 1038, 889, 866, 848, 812, 751, 709, 689, 586, 558,
5727
dx.doi.org/10.1021/jm300596s | J. Med. Chem. 2012, 55, 5720−5733

Journal of Medicinal Chemistry
Article
28.00; HRMS (ES+) m/z found 342.0251; C18H15BrO2 (M+) requires
342.0255.
HPLC: 95.1%. IR (KBr) ν (cm−1): 3088, 3064, 3023, 3000, 2965,
2945, 2908, 2855, 2832, 1693, 1608, 1574, 1543, 1492, 1465, 1435,
1357, 1324, 1301, 1279, 1235, 1193, 1169, 1099, 1046, 904, 867, 826,
808, 748, 719, 592. 1H NMR (300 MHz, CDCl3) δ 7.73 (s, 1H), 7.31
(dd, J = 8.4, 1.8 Hz, 1H), 7.18 (d, J = 8.4 Hz, 1H), 7.11 (d, J = 8.4 Hz,
1H), 6.89 (dd, J = 8.4, 2.7 Hz, 1H), 6.77 (dd, J = 8.1, 2.4 Hz, 1H), 6.56
(d, J = 2.7 Hz, 1H), 3.48 (s, 3H), 3.02 (t, J = 6.6 Hz, 2H), 2.65 (t, J =
6.6 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 200.53, 158.96, 136.76,
135.60, 134.82, 133.19, 132.01, 130.81, 129.41, 128.86, 126.37, 114.39,
110.59, 55.44, 39.02, 27.28; HRMS (ES+) m/z found 332.0368;
C18H14Cl2O2 (M+) requires 332.0371.
(E)-1-(4-Bromobenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (11c). Yield 56%, yellow crystal. Mp: 130−132 °C.
HPLC: 96.5%. IR (KBr) ν (cm−1): 3089, 2955, 2836, 1688, 1599,
1573, 1474, 1460, 1436, 1394, 1362, 1340, 1298, 1266, 1252, 1164,
1100, 1067, 1012, 1010, 986, 967, 906, 889, 846, 817, 797, 783, 733,
1
711, 697, 669, 647, 568, 545, 499, 476, 441. H NMR (300 MHz,
CDCl3) δ 7.57 (s, 1H), 7.38 (d, J = 8.7 Hz, 2H), 7.25 (d, J = 8.4 Hz,
2H), 6.98 (d, J = 8.1 Hz, 1H), 6.87 (d, J = 7.8 Hz, 1H), 6.79 (d, J = 8.1
Hz, 1H), 3.88 (s, 3H), 3.08 (t, J = 6.6 Hz, 2H), 2.56 (t, J = 6.6 Hz,
2H); 13C NMR (300 MHz, CDCl3) δ 201.81, 156.27, 134.38, 134.21,
133.86, 133.58, 131.54, 131.17, 127.12, 126.74, 122.92, 121.23, 109.88,
55.56, 36.43, 19.29; HRMS (ES+) m/z found 342.0258; C18H15BrO2
(M+) requires 342.0255.
(E)-1-(2,4-Dichlorobenzylidene)-6-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (14b). Yield 40%, yellow powder. Mp: 122−
1
124 °C. HPLC: 96.3%. H NMR (300 MHz, CDCl3) δ 7.74 (s, 1H),
7.49 (dd, J = 7.8, 1.8 Hz, 1H), 7.42−7.47 (m, 1H), 7.39 (s, 1H), 7.32
(d, J = 8.4 Hz, 1H), 7.20−7.25 (m, 1H), 6.61 (dd, J = 8.7, 2.4 Hz, 1H),
3.84 (s, 3H), 3.02 (t, J = 6.6 Hz, 2H), 2.67 (t, J = 6.6 Hz, 2H); HRMS
(ES+) m/z found 332.0370; C18H14Cl2O2 (M+) requires 332.0371.
(E)-1-(2,4-Dichlorobenzylidene)-7-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (14c). Yield 47%, yellow powder. Mp: 126−
128 °C. HPLC: 97.3%. IR (KBr) ν (cm−1): 3089, 3066, 2998, 2958,
2901, 2829, 1695, 1603, 1577, 1475, 1453, 1359, 1294, 1262, 1226,
1098, 1080, 1049, 1019, 996, 881, 861, 823, 771, 733, 579, 555, 448.
1H NMR (300 MHz, CDCl3) δ 7.45 (s, 1H), 7.31 (d, J = 7.8 Hz, 1H),
(E)-1-(4-Chlorobenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (12a). Yield 46%, yellow powder. Mp: 140−
1
142 °C. HPLC: 97.1%. H NMR (300 MHz, CDCl3) δ 7.62 (s, 1H),
7.39 (d, J = 8.7 Hz, 2H), 7.28 (d, J = 8.4 Hz, 1H), 6.89 (d, J = 8.7 Hz,
2H), 6.84 (dd, J = 8.4, 2.4 Hz, 1H), 6.79 (d, J = 8.4 Hz, 1H), 3.52 (s,
3H), 3.00 (t, J = 6.3 Hz, 2H), 2.58 (t, J = 6.3 Hz, 2H); HRMS (ES+)
m/z found 299.0835; C18H15ClO2 (M + H+) requires 299.0839.
(E)-1-(4-Chlorobenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (12b). Yield 42%, yellow powder. Mp: 142−
1
144 °C. HPLC: 97.1%. H NMR (300 MHz, CDCl3) δ 7.43 (s, 1H),
7.22 (dd, J = 8.1, 1.5 Hz, 1H), 7.15 (s, 1H), 7.09 (d, J = 8.4 Hz, 1H),
6.54−6.62 (m, 1H), 3.80 (s, 3H), 3.01 (t, J = 6.3 Hz, 2H), 2.58 (t, J =
6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.05, 156.29, 137.01,
135.59, 134.74, 133.63, 131.93, 130.94, 129.65, 128.86, 127.10, 126.76,
125.63, 121.31, 109.95, 55.60, 38.48, 20.71; HRMS (ES+) m/z found
332.0370; C18H14Cl2O2 (M+) requires 332.0371.
7.31 (d, J = 8.7 Hz, 2H), 7.22 (d, J = 8.4 Hz, 2H), 7.21 (d, J = 8.7 Hz,
1H), 6.78 (d, J = 2.7 Hz, 1H), 6.57 (dd, J = 8.7, 2.7 Hz, 1H), 3.83 (s,
3H), 2.99 (t, J = 6.6 Hz, 2H), 2.62 (t, J = 6.6 Hz, 2H); HRMS (ES+)
m/z found 298.0758; C18H15ClO2 (M+) requires 298.0761.
(E)-1-(4-Chlorobenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (12c). Yield 46%, yellow powder. Mp: 148−
150 °C. HPLC: 95.9%. IR (KBr) ν (cm−1): 3089, 3046, 3009, 2989,
2958, 2936, 2901, 2857, 2835, 1691, 1600, 1574, 1480, 1438, 1397,
1363, 1339, 1301, 1269, 1250, 1164, 1093, 1068, 1009, 965, 909, 823,
(E)-1-(3,4-Dichlorobenzylidene)-5-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (15a). Yield 35%, yellow powder. Mp: 118−
1
120 °C. HPLC: 96.8%. H NMR (300 MHz, CDCl3) δ 7.54 (s, 1H),
1
7.35 (s, 1H), 7.18−7.26 (m, 2H), 7.04−7.12 (m, 2H), 6.64−6.72 (m,
1H), 3.69 (s, 3H), 2.96 (t, J = 6.3 Hz, 1H), 2.67 (t, J = 6.3 Hz, 1H);
13C NMR (300 MHz, CDCl3) δ 200.53, 158.96, 136.76, 135.60,
134.82, 133.19, 132.01, 130.81, 129.41, 128.86, 126.37, 114.39, 110.59,
55.44, 39.02, 27.28; HRMS (ES+) m/z found 332.0370; C18H14Cl2O2
(M+) requires 332.0371.
800, 781, 733, 668, 566, 501. H NMR (300 MHz, CDCl3) δ 7.59 (s,
1H), 7.32 (d, J = 8.4 Hz, 2H), 7.21 (d, J = 8.4 Hz, 2H), 6.99 (t, J = 8.1
Hz, 1H), 6.88 (d, J = 8.1 Hz, 1H), 6.79 (d, J = 8.1 Hz, 1H), 3.88 (s,
3H), 3.08 (t, J = 6.3 Hz, 2H), 2.57 (t, J = 6.3 Hz, 2H); 13C NMR (300
MHz, CDCl3) δ 201.87, 156.26, 134.60, 133.82, 133.74, 133.60,
130.93, 128.57, 127.13, 126.70, 121.22, 109.87, 55.55, 36.43, 19.29;
HRMS (ES+) m/z found 299.0832; C18H15ClO2 (M + H+) requires
299.0839.
(E)-1-(3,4-Dichlorobenzylidene)-6-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (15b). Yield 42%, yellow crystal. Mp: 124−
1
(E)-1-(2-Chlorobenzylidene)-5-methoxy-3,4-dihydronaph-
126 °C. HPLC: 96.2%. H NMR (300 MHz, CDCl3) δ 7.63 (s, 1H),
thalen-2(1H)-one (13a). Yield 46%, yellow powder. Mp: 98−100 °C.
7.54 (d, J = 8.4 Hz, 1H), 7.50 (d, J = 8.4 Hz, 1H), 7.42 (dd, J = 11.1,
2.1 Hz, 2H), 6.99−7.07 (m, 1H), 6.78 (s, 1H), 6.55 (dd, J = 8.7, 2.7
Hz, 1H), 3.86 (s, 3H), 3.04 (t, J = 6.6 Hz, 2H), 2.62 (t, J = 6.6 Hz,
2H); HRMS (ES+) m/z found 332.0374; C18H14Cl2O2 (M+) requires
332.0371.
1
HPLC: 96.2%. H NMR (300 MHz, CDCl3) δ 7.83 (s, 1H), 7.43 (d,
J = 8.1 Hz, 1H), 7.20−7.26 (m, 2H), 7.09−7.18 (m, 2H), 6.76 (dd, J =
8.1, 2.4 Hz, 1H), 6.56 (d, J = 2.7 Hz, 1H), 3.40 (s, 3H), 3.00 (t, J = 6.3
Hz, 2H), 2.66 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ
200.72, 157.58, 135.18, 134.77, 134.49, 132.98, 132.30, 130.68, 130.08,
129.87, 129.65, 128.89, 126.43, 115.44, 113.10, 54.91, 37.46, 26.91;
HRMS (ES+) m/z found 298.0783; C18H15ClO2 (M+) requires
298.0761.
(E)-1-(3,4-Dichlorobenzylidene)-7-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (15c). Yield 52%, yellow crystal. Mp: 124−
126 °C. HPLC: 95.8%. IR (KBr) ν (cm−1): 3445, 2998, 2961, 2914,
2831, 1686, 1542, 1473, 1453, 1385, 1351, 1290, 1262, 1226, 1182,
1131, 1078, 1022, 978, 897, 855, 810, 770, 704, 663, 581, 554, 491,
(E)-1-(2-Chlorobenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (13b). Yield 50%, yellow crystal. Mp: 122−
1
432. H NMR (300 MHz, CDCl3) δ 7.52 (s, 1H), 7.37 (s, 1H), 7.23
1
124 °C. HPLC: 97.2%. H NMR (300 MHz, CDCl3) δ 7.63 (s, 1H),
(dd, J = 7.8, 2.4 Hz, 1H), 7.05 (dd, J = 8.4, 2.4 Hz, 1H), 6.89 (d, J =
8.1 Hz, 1H), 7.02 (dd, J = 8.4, 1.8 Hz, 1H), 6.89 (d, J = 7.8 Hz, 1H),
3.88 (s, 3H), 3.09 (t, J = 6.3 Hz, 2H), 2.64 (t, J = 6.3 Hz, 2H); HRMS
(ES+) m/z found 332.0370; C18H14Cl2O2 (M+) requires 332.0371.
(E)-1-(2,6-Dichlorobenzylidene)-5-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (16a). Yield 30%, yellow powder. Mp: 120−
122 °C. HPLC: 95.8%. IR (KBr) ν (cm−1): 3081, 3026, 2993, 2963,
2915, 2861, 2839, 1698, 1615, 1571, 1487, 1428, 1348, 1301, 1276,
7.38 (d, J = 8.1 Hz, 1H), 7.20−7.24 (m, 2H), 7.15−7.26 (m, 2H), 6.56
(dd, J = 8.4, 2.4 Hz, 1H), 6.56 (d, J = 2.4 Hz, 1H), 3.63 (s, 3H), 2.99
(t, J = 6.3 Hz, 2H), 2.68 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz,
CDCl3) δ 201.72, 160.01, 140.24, 135.41, 134.52, 133.86, 132.01,
130.48, 129.93, 128.86, 128.35, 126.88, 124.36, 113.09, 112.30, 55.40,
38.93, 28.54; HRMS (ES+) m/z found 298.0754; C18H15ClO2 (M+)
requires 298.0761.
(E)-1-(2-Chlorobenzylidene)-7-methoxy-3,4-dihydronaph-
1
1236, 1191, 1165, 1096, 1036, 992, 879, 860, 819, 779, 742, 700. H
thalen-2(1H)-one (13c). Yield 50%, yellow crystal. Mp: 124−126 °C.
1
NMR (300 MHz, CDCl3) δ 7.57 (s, 1H), 7.31 (d, J = 8.4 Hz, 2H),
7.20 (d, J = 7.2 Hz, 1H), 7.14 (d, J = 8.7 Hz, 1H), 6.74 (dd, J = 8.4, 2.7
Hz, 1H), 6.30 (d, J = 2.7 Hz, 1H), 3.36 (s, 3H), 2.99 (t, J = 6.3 Hz,
1H), 2.69 (t, J = 6.3 Hz, 1H); 13C NMR (300 MHz, CDCl3) δ 200.37,
157.87, 137.78, 134.66, 134.23, 133.81, 130.20, 129.27, 129.11, 128.75,
128.17, 115.48, 111.28, 54.79, 37.38, 26.76; HRMS (ES+) m/z found
332.0372; C18H14Cl2O2 (M+) requires 332.0371.
HPLC: 95.6%. H NMR (300 MHz, CDCl3) δ 7.78 (s, 1H), 7.38 (d,
J = 8.4 Hz, 1H), 7.12 (d, J = 7.8 Hz, 1H), 7.04 (dd, J = 8.1, 2.4 Hz,
2H), 6.96 (s, 1H), 6.72−6.80 (m, 1H), 6.54−6.58 (m, 1H), 3.76 (s,
3H), 3.09 (t, J = 6.6 Hz, 2H), 2.63 (t, J = 6.6 Hz, 2H); HRMS (ES+)
m/z found 298.0760; C18H15ClO2 (M+) requires 298.0761.
(E)-1-(2,4-Dichlorobenzylidene)-5-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (14a). Yield 42%, yellow powder. Mp: 118−120 °C.
5728
dx.doi.org/10.1021/jm300596s | J. Med. Chem. 2012, 55, 5720−5733

Journal of Medicinal Chemistry
Article
(E)-1-(3-Hydroxybenzylidene)-6-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (16b). Yield 35%, yellow crystal. Mp: 168−
3.83 (s, 3H), 2.98 (t, J = 6.3 Hz, 2H), 2.59 (t, J = 6.3 Hz, 2H);
13C NMR (300 MHz, CDCl3) δ 202.01, 159.30, 147.25, 145.21,
139.99, 133.34, 131.97, 130.22, 128.63, 125.18, 122.98, 115.05, 112.72,
112.07, 110.35, 55.86, 55.22, 37.08, 28.08; HRMS (ES+) m/z found
310.1204; C19H18O4 (M+) requires 310.1205.
1
170 °C. HPLC: 96.9%. H NMR (300 MHz, CDCl3) δ 7.54 (s, 1H),
7.30 (d, J = 8.7 Hz, 1H), 7.15 (d, J = 7.8 Hz, 1H), 7.00 (d, J = 7.8 Hz,
1H), 6.92 (s, 1H), 6.78 (d, J = 7.8 Hz, 2H), 6.59 (dd, J = 8.7, 2.7 Hz,
1H), 3.86 (s, 3H), 3.00 (t, J = 6.3 Hz, 2H), 2.63 (t, J = 6.3 Hz, 2H);
13C NMR (300 MHz, CDCl3) δ 200.37, 157.87, 137.78, 134.66,
134.23, 133.81, 130.20, 129.27, 129.11, 128.75, 128.17, 115.48, 111.28,
54.79, 37,38, 26.76; HRMS (ES+) m/z found 280.1036; C18H16O3
(M+) requires 280.1099.
(E)-1-(3-Hydroxybenzylidene)-7-methoxy-3,4-dihydronaph-
thalen-2(1H)-one (16c). Yield 35%, yellow crystal. Mp: 160−162 °C.
HPLC: 97.7%. IR (KBr) ν (cm−1): 3174, 2976, 2361, 1673, 1591,
1571, 1451, 1364, 1343, 1286, 1261, 1196, 1162, 1067, 1022, 1001,
974, 942, 906, 880, 867, 792, 732, 692, 592, 564, 532, 482, 462, 430.
1H NMR (300 MHz, CDCl3) δ 7.63 (s, 1H), 7.14 (d, J = 8.4 Hz, 1H),
7.00 (d, J = 8.4 Hz, 1H), 6.94−6.98 (m, 2H) 6.89 (s, 1H), 6.74−6.80
(m, 2H), 5.22 (s, 1H), 3.88 (s, 3H), 3.08 (t, J = 6.3 Hz, 2H), 2.58 (t,
J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.37, 156.14,
155.50, 136.76, 135.19, 134.19, 133.80, 129.62, 126.98, 126.61, 122.27,
121.57, 116.07, 109.78, 55.57, 36.54, 19.29; HRMS (ES+) m/z found
280.1096; C18H16O3 (M+) requires 280.1099.
(E)-1-(3-Hydroxy-4-methoxybenzylidene)-7-methoxy-3,4-di-
hydronaphthalen-2(1H)-one (18c). Yield 43%, yellow crystal. Mp:
178−180 °C. HPLC: 99.7%. IR (KBr) ν (cm−1): 3315, 3005, 2961,
2940, 2905, 2882, 2840, 2733, 1681, 1590, 1506, 1471, 1441, 1370,
1344, 1283, 1251, 1173, 1130, 1068, 1027, 997, 971, 944, 908, 806,
780, 757, 730, 673, 615, 503, 434. 1H NMR (300 MHz, CDCl3) δ 7.57
(s, 1H), 7.05 (d, J = 7.8 Hz, 2H), 7.02 (dd, J = 7.8, 2.4 Hz, 2H), 6.97
(dd, J = 8.1, 2.1 Hz, 1H), 6.76 (dd, J = 8.4, 2.7 Hz, 2H), 5.61 (s, 1H),
3.89 (s, 3H), 3.87 (s, 3H), 3.05 (t, J = 6.6 Hz, 2H), 2.54 (t, J = 6.6 Hz,
2H); 13C NMR (300 MHz, CDCl3) δ 202.32, 156.13, 147.46, 145.12,
135.38, 134.20, 132.54, 128.30, 126.92, 126.50, 123.28, 121.31, 115.37,
110.24, 109.60, 55.86, 55.55, 36.59, 19.30; HRMS (ES+) m/z found
310.1204; C19H18O4 (M+) requires 310.1205.
(E)-1-(4-Hydroxy-3-methoxybenzylidene)-5-methoxy-3,4-di-
hydronaphthalen-2(1H)-one (19a). Yield 49%, yellow crystal. Mp:
158−160 °C. HPLC: 99.3%. IR (KBr) ν (cm−1): 3359, 3002, 2945,
2841, 1677, 1612, 1573, 1516, 1489, 1444, 1383, 1306, 1284, 1247,
1230, 1204, 1166, 1121, 1096, 1044, 1025, 934, 801, 626, 548, 481,
422. 1H NMR (300 MHz, CDCl3) δ 7.60 (s, 1H), 7.18 (d, J = 8.4 Hz,
1H), 7.09 (s, 1H), 7.04 (d, J = 2.7 Hz, 2H), 6.83 (d, J = 8.4 Hz, 1H),
6.76 (dd, J = 8.4, 2.7 Hz, 1H), 5.97 (s, 1H), 3.71 (s, 3H), 3.64 (s, 3H),
2.96 (t, J = 6.3 Hz, 2H), 2.60 (t, J = 6.3 Hz, 2H); 13C NMR (300
MHz, CDCl3) δ 201.81, 157.46, 147.01, 146.15, 135.63, 133.70,
131.82, 130.81, 128.85, 126.79, 124.76, 114.65, 114.46, 113.31, 112.02,
55.77, 55.21, 37.36, 26.92; HRMS (ES+) m/z found 310.1209;
C19H18O4 (M+) requires 310.1205.
(E)-1-(4-Dimethylaminobenzylidene)-5-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (17a). Yield 58%, yellow crystal. Mp:
1
118−119 °C. HPLC: 99.3%. H NMR (300 MHz, CDCl3) δ 7.57 (s,
1H), 7.23 (d, J = 8.1 Hz, 2H), 7.14 (d, J = 8.4 Hz, 2H), 6.76 (dd, J =
8.1, 2.4 Hz, 1H), 6.56 (d, J = 2.7 Hz, 2H), 3.68 (s, 3H), 3.10 (s, 6H),
2.89 (t, J = 6.3 Hz, 1H), 2.65 (t, J = 6.3 Hz, 1H); 13C NMR (300
MHz, CDCl3) δ 201.16, 157.50, 151.00, 136.59, 134.70, 132.09,
130.59, 129.44, 128.63, 114.30, 112.74, 111.42, 55.28, 40.18, 37.56,
27.07; HRMS (ES+) m/z found 307.1576; C20H21NO2 (M+) requires
307.1572.
(E)-1-(4-Hydroxy-3-methoxybenzylidene)-6-methoxy-3,4-di-
hydronaphthalen-2(1H)-one (19b). Yield 52%, yellow crystal. Mp:
(E)-1-(4-Dimethylaminobenzylidene)-6-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (17b). Yield 52%, yellow crystal. Mp:
128−130 °C. HPLC: 97.5%. IR (KBr) ν (cm−1): 2905, 2360, 1676,
1607, 1582, 1522, 1490, 1431, 1363, 1301, 1264, 1229, 1191, 1147,
1136, 1101, 1066, 1031, 1015, 945, 900, 867, 847, 821, 807, 718, 668,
662, 564, 510, 474. 1H NMR (300 MHz, CDCl3) δ 7.56 (s, 1H), 7.54
(s, 1H), 7.47 (s, 1H), 7.44 (s, 1H), 6.79 (d, J = 2.7 Hz, 1H), 6.65 (dd,
J = 8.7, 2.7 Hz, 1H), 6.58 (d, J = 8.7 Hz, 2H), 3.84 (s, 3H), 3.00
(s, 6H), 2.96 (t, J = 6.3 Hz, 2H), 2.57 (t, J = 6.3 Hz, 2H); 13C NMR
(300 MHz, CDCl3) δ 201.98, 158.87, 150.74, 139.82, 134.69, 131.64,
129.83, 129.15, 126.28, 112.60, 111.91, 111.44, 55.26, 40.14, 37.32,
28.24; HRMS (ES+) m/z found 307.1575; C20H21NO2 (M+) requires
307.1572.
(E)-1-(4-Dimethylaminobenzylidene)-7-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (17c). Yield 48%, yellow crystal. Mp:
98−100 °C. HPLC: 97.5%. 1H NMR (300 MHz, CDCl3) δ 7.63
(s, 1H), 7.56(d, J = 8.1 Hz, 2H), 7.37 (d, J = 7.8 Hz, 1H), 6.79 (d, J =
2.7 Hz, 1H), 6.65 (dd, J = 8.7, 2.7 Hz, 3H), 3.92 (s, 3H), 3.12 (s, 6H),
3.06 (t, J = 6.3 Hz, 2H), 2.53 (t, J = 6.3 Hz, 2H); HRMS (ES+) m/z
found 307.1589; C20H21NO2 (M+) requires 307.1572.
1
153−155 °C. HPLC: 98.6%. H NMR (300 MHz, CDCl3) δ 7.53 (s,
1H), 7.45 (d, J = 8.7 Hz, 1H), 7.06 (s, 1H), 7.02 (s, 1H), 6.83 (s, 1H),
6.80 (s, 1H), 6.63 (dd, J = 8.7, 2.7 Hz, 1H), 5.85 (s, 1H), 3.83 (s, 3H),
3.72 (s, 3H), 2.99 (t, J = 6.6 Hz, 2H), 2.60 (t, J = 6.6 Hz, 2H); 13C
NMR (300 MHz, CDCl3) δ 201.67, 159.26, 146.65, 146.11, 140.16,
133.70, 131.36, 130.27, 127.33, 125.31, 124.44, 114.42, 112.73, 111.88,
111.60, 55.77, 55.27, 37.11, 28.13; HRMS (ES+) m/z found 310.1206;
C19H18O4 (M+) requires 310.1205.
(E)-1-(4-Hydroxy-3-methoxybenzylidene)-7-methoxy-3,4-di-
hydronaphthalen-2(1H)-one (19c). Yield 50%, yellow crystal. Mp:
1
160−162 °C. HPLC: 98.6%. H NMR (300 MHz, CDCl3) δ 7.60 (s,
1H), 7.11 (d, J = 7.8 Hz, 1H), 7.02 (d, J = 7.8, 2.1 Hz, 2H), 6.99 (s,
1H), 6.80 (dd, J = 8.1, 2.1 Hz, 2H), 5.98−6.02 (m, 1H), 3.88 (s, 3H),
3.67 (s, 3H), 3.06 (t, J = 6.3 Hz, 2H), 2.55 (t, J = 6.3 Hz, 2H); 13C
NMR (300 MHz, CDCl3) δ 202.38, 156.17, 146.96, 146.05, 135.77,
134.32, 131.79, 127.03, 126.91, 126.27, 124.97, 121.33, 114.40, 111.84,
109.46, 55.72, 55.53, 36.61, 19.32; HRMS (ES+) m/z found 310.1209;
C19H18O4 (M+) requires 310.1205.
(E)-1-(3,4-Dimethoxybenzylidene)-5-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (20a). Yield 50%, yellow solid. Mp: 84−
(E)-1-(3-Hydroxy-4-methoxybenzylidene)-5-methoxy-3,4-di-
1
hydronaphthalen-2(1H)-one (18a). Yield 42%, yellow crystal. Mp:
86 °C. HPLC: 97.2%. H NMR (300 MHz, CDCl3) δ 7.62 (s, 1H),
1
170−172 °C. HPLC: 95.1%. H NMR (300 MHz, CDCl3) δ 7.59 (s,
7.28 (d, J = 8.4 Hz, 1H), 7.00 (dd, J = 8.4, 2.4 Hz, 1H), 6.95 (s, 1H),
6.68 (d, J = 2.4 Hz, 2H), 6.62 (dd, J = 8.7, 2.4 Hz, 1H), 3.85(s, 6H),
3.63 (s, 3H), 2.92 (t, J = 6.3 Hz, 2H), 2.61 (t, J = 6.3 Hz, 2H); HRMS
(ES+) m/z found 324.1360; C20H20O4(M+) requires 324.1362.
(E)-1-(3,4-Dimethoxybenzylidene)-6-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (20b). Yield 50%, yellow powder. Mp: 114−
1H), 7.16 (d, J = 7.6 Hz, 2H), 7.11 (s, 1H), 7.01 (s, 2H), 6.77 (d, J =
7.8 Hz, 2H), 5.71 (s, 1H), 3.89 (s, 3H), 3.57 (s, 3H), 2.95 (s, 1H),
2.59 (s, 3H); 13C NMR (300 MHz, CDCl3) δ 201.91, 157.52, 147.55,
145.21, 135.37, 133.54, 132.31, 130.72, 128.74, 128.06, 123.32, 115.38,
114.97, 113.18, 110.32, 55.88, 55.24, 37.33, 26.89; HRMS (ES+) m/z
found 310.1211; C19H18O4 (M+) requires 310.1205.
1
116 °C. HPLC: 95.3%. H NMR (300 MHz, CDCl3) δ 7.52 (s, 1H),
7.42 (d, J = 8.7 Hz, 1H), 7.07 (dd, J = 8.7, 2.2 Hz, 1H), 7.03 (s, 1H),
6.76 (d, J = 8.7 Hz, 1H), 6.62 (dd, J = 8.4 Hz, 2.2 Hz, 1H), 3.90 (s,
3H), 3.85 (s, 6H), 2.99 (t, J = 6.3 Hz, 2H), 2.62 (t, J = 6.3 Hz, 2H);
HRMS (ES+) m/z found 324.1361; C20H20O4(M+) requires 324.1362.
(E)-1-(3,4-Dimethoxybenzylidene)-7-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (20c). Yield 43%, yellow crystal. Mp: 114−
116 °C. HPLC: 95.5%. IR (KBr) ν (cm−1): 3005, 2950, 2835, 2361,
1686, 1595, 1579, 1509, 1471, 1440, 1418, 1370, 1342, 1250, 1157,
1137, 1070, 1016, 968, 903, 860, 807, 793, 781, 768, 735, 695, 674,
(E)-1-(3-Hydroxy-4-methoxybenzylidene)-5-methoxy-3,4-di-
hydronaphthalen-2(1H)-one (18b). Yield 48%, yellow crystal. Mp:
170−172 °C. HPLC: 96.4%. IR (KBr) ν (cm−1): 3556, 2999, 2939,
2902, 2839, 1681, 1613, 1585, 1570, 1510, 1484, 1436, 1367, 1332,
1277, 1245, 1196, 1161, 1129, 1094, 1039, 1021, 999, 926, 901, 873,
816, 796, 760, 727, 622, 562, 487, 424; 1H NMR (300 MHz, CDCl3) δ
7.50 (s, 1H), 7.38 (d, J = 8.4 Hz, 1H), 7.06 (d, J = 2.1 Hz, 1H), 7.01
(dd, J = 8.7, 2.1 Hz, 1H), 6.78 (d, J = 2.1 Hz, 1H), 6.76 (d, J = 8.4 Hz,
1H), 6.62 (dd, J = 8.7, 2.7 Hz, 1H), 5.55 (s, 1H), 3.90 (s, 3H),
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623, 604, 553, 460, 437. 1H NMR (300 MHz, CDCl3) δ 7.61 (s, 1H),
7.00−7.10 (m, 4H), 6.78 (d, J = 8.4 Hz, 2H), 3.89 (s, 6H), 3.64
(s, 3H), 3.07 (t, J = 6.3 Hz, 2H), 2.56 (t, J = 6.3 Hz, 2H); 13C NMR
(300 MHz, CDCl3) δ 202.08, 156.17, 150.04, 148.26, 135.43, 134.31,
132.08, 127.47, 127.05, 126.27, 124.48, 121.41, 112.02, 110.70, 109.47,
55.80, 55.57, 55.53, 36.59, 19.34; HRMS (ES+) m/z found 324.1364;
C20H20O4(M+) requires 324.1362.
(E)-1-(2,3,4-Trimethoxybenzylidene)-6-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (23b). Yield 43%, yellow powder. Mp:
112−114 °C. HPLC: 96.1%. H NMR (300 MHz, CDCl3) δ 7.73 (s,
1
1H), 7.30 (d, J = 8.4 Hz, 1H), 7.03 (d, J = 8.7 Hz, 1H), 6.77 (s, 1H),
6.57 (dd, J = 8.7, 2.2 Hz, 1H), 6.37 (d, J = 8.7 Hz, 1H), 3.90 (s, 6H),
3.85 (s, 6H), 2.99 (t, J = 6.3 Hz, 2H), 2.62 (t, J = 6.3 Hz, 2H); HRMS
(ES+) m/z found 354.1464; C21H22O5(M+) requires 354.1467.
(E)-1-(2,3,4-Trimethoxybenzylidene)-7-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (23c). Yield 46%, yellow solid. Mp: 78−
(E)-1-(3,5-Dimethoxybenzylidene)-5-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (21a). Yield 48%, yellow crystal. Mp: 126−
128 °C. HPLC: 95.7%. IR (KBr) ν (cm−1): 2955, 2833, 2360, 1691,
1584, 1491, 1459, 1361, 1341, 1318, 1299, 1279, 1233, 1201, 1163,
1099, 1068, 1038, 995, 914, 874, 843, 816, 805, 744, 714, 689, 546,
1
80 °C. HPLC: 97.4%. H NMR (300 MHz, CDCl3) δ 7.60 (s, 1H),
6.93−6.99 (m, 1H), 6.87 (d, J = 2.4 Hz, 1H), 6.73 (s, 1H), 6.68 (dd,
J = 8.7, 2.4 Hz, 1H), 6.50 (d, J = 8.4 Hz, 1H), 3.92 (s, 6H), 3.73
(s, 6H), 2.99 (t, J = 6.3 Hz, 2H), 2.61 (t, J = 6.3 Hz, 2H); HRMS
(ES+) m/z found 354.1466; C21H22O5(M+) requires 354.1467.
Biology. Cytotoxicity Assay. Cytotoxic effects were examined in
the MDA-MB-435 human breast carcinoma, HCT-116 human colon
carcinoma, and CEM human leukemia cell lines. Cells in logarithmic
phase were diluted to a density of 40000−50000 cells/mL in culture
medium based on growth characteristics. For each well of a 96-well
microplate, 100 μL of cell dilution was seeded, allowed to attach
overnight, and then exposed to varying concentrations (10−4−10−9 M)
of compounds for 72 h (37 °C, 5% CO2 atmosphere). The number of
living cells was estimated by the MTT assay. Absorbance at 570 nm
was recorded on a Wellscan MK-2 multifunction microplate reader
(Labsystems Inc.). Compounds were tested in triplicate in at least
three independent assays. The IC50 values were determined by a
nonlinear regression analysis. Average values were reported.
1
484, 423. H NMR (300 MHz, CDCl3) δ 7.62 (s, 1H), 7.17 (d, J =
8.4 Hz, 1H), 6.91 (d, J = 2.4 Hz, 1H), 6.77 (dd, J = 8.4, 2.7 Hz, 1H),
6.58 (d, J = 2.1 Hz, 2H), 6.39 (d, J = 2.1 Hz, 1H), 3.68 (s, 6H), 3.53
(s, 3H), 2.99 (t, J = 6.3 Hz, 2H), 2.62 (t, J = 6.3 Hz, 2H); 13C NMR
(300 MHz, CDCl3) δ 201.61, 160.62, 157.45, 136.90, 135.22, 134.16,
133.14, 130.76, 128.79, 115.32, 113.51, 107.32, 101,64, 55.29, 55.15,
37.28, 26.87; HRMS (ES+) m/z found 324.1365; C20H20O4(M+)
requires 324.1362.
(E)-1-(3,5-Dimethoxybenzylidene)-6-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (21b). Yield 53%, yellow crystal. Mp: 126−
128 °C. HPLC: 98.8%. IR (KBr) ν (cm−1): 2959, 2836, 2362, 1687,
1594, 1498, 1448, 1424, 1373, 1336, 1309, 1263, 1252, 1222, 1205,
1
1154, 1093, 1053, 1027, 904, 850, 834, 694, 672 619, 563, 537. H
NMR (300 MHz, CDCl3) δ 7.52 (s, 1H), 7.33 (d, J = 8.7 Hz, 1H),
6.78 (d, J = 2.4 Hz, 1H), 6.62 (d, J = 8.7 Hz, 1H), 6.58 (d, J = 8.7 Hz,
1H), 6.38 (d, J = 2.4 Hz, 1H), 3.83 (s, 3H), 3.69 (s, 6H), 3.01 (t, J =
6.3 Hz, 2H), 2.63 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ
201.61, 160.59, 159.47, 140.09,137.32, 133.59, 133.23, 130.79, 124.82,
112.68, 111.98, 107.17, 101.37, 55.27, 37.00, 28.05; HRMS (ES+) m/z
found 324.1363; C20H20O4 (M+) requires 324.1362.
Tubulin Polymerization Assay.63,64 Procine brain tubulin was
purchased from cytoskeleton. Tubulin (>99% pure, 3 mg/mL) in
100 μL of general tubulin buffer (80 mM PIPES, pH 6.9, 0.5 mM
EGTA, 2 mM MgCl2, 1 mM GTP, and 5% glycerol) at 0 °C was
placed in a prewarmed half area 96-well plate at 37 °C in the presence
of tested compounds at varying concentrations. The reaction was
started by warming the samples at 37 °C. The mass of polymer formed
was monitored by turbidimetry at 340 nm every 1 min for 60 min with
a BioTek’s Synergy 4 multifunction microplate reader.
Cell Cycle Analysis. For flow cytometric analysis of DNA content,
106 HCT-116 cells in exponential growth were treated with varying
concentrations of compound 22b for 24 h. After centrifugation, the
cell pellet was fixed in 2 mL of citrate buffer. Fixed cells were treated
with 1.5 mL of RNase A for 20 min. Samples were analyzed on a BD
FACStar Plus cell sorter flow cytometer. The percentage of each phase
of the cell cycle (G1, S, G2/M) was calculated on living cells. The
percentage of apoptotic cells is referred to the cell populations
characterized by the appearance of a sub-G1-peak.
In Vivo Antitumor Activity. Four-week-old female BALB/c nude
mice (18−20 g) were obtained from Shanghai SLAC Laboratory
Animal Co., Ltd. (Shanghai, China). The animals were maintained
under specific pathogen-free conditions in Shanghai Institute of Phar-
maceutical Industry. Once the HT-29 xenografts reached a size of
around 100 mm3, mice were randomly assigned into corresponding
groups and injected intraperitoneally at 0.1 mL per 20 g of body
weight.65 The drugs or vehicle were administered once a day. After
completing the treatment schedule and the evaluation period, tumor-
bearing mice were euthanized. Tumor volume (TV) was calculated by
the formula: TV= (ab2)/2 where a is the length and b is the width of
the tumor nodules determined once per 4 days by caliper measure-
ments and recorded along with body weights. The study was approved
by Shanghai Institute of Pharmaceutical Industry.
(E)-1-(3,5-Dimethoxybenzylidene)-7-methoxy-3,4-dihydro-
naphthalen-2(1H)-one (21c). Yield 50%, yellow powder. Mp: 126−
1
128 °C. HPLC: 99.1%. H NMR (300 MHz, CDCl3) δ 7.59 (s, 1H),
6.97−7.04 (m, 2H), 6.78 (dd, J = 6.6, 2.4 Hz, 1H), 6.54 (s, 2H), 6.39
(d, J = 2.2 Hz, 1H), 3.87 (s, 3H), 3.67 (s, 6H), 3.08 (t, J = 6.6 Hz,
2H), 2.58 (t, J = 6.6 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 202.09,
160,49, 156.07, 136.94, 135.27, 134.24, 133.79, 127.02, 126.38, 121.76,
109.74, 107.40, 101.67, 55.52, 55.24, 36.49, 19.30; HRMS (ES+) m/z
found 324.1381; C20H20O4 (M+) requires 324.1362.
(E)-1-(3,4,5-Trimethoxybenzylidene)-5-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (22a). Yield 1.89 g (53%). Mp: 115−
1
117 °C. HPLC: 99.6%. H NMR (300 MHz, CDCl3) δ 7.58 (s, 1H),
7.18 (d, J = 8.4 Hz, 1H), 7.00 (s, 1H), 6.78 (dd, J = 8.4, 2.7 Hz, 1H),
6.73 (s, 2H), 3.86 (s, 3H), 3.70 (s, 6H), 3.56 (s, 3H), 2.98 (t, J =
6.6 Hz, 2H), 2.60 (t, J = 6.6 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ
201.60, 157.39, 152.91, 138.97, 135.12, 133.22, 130.84, 129.99, 128.89,
114.89, 113.52, 107.16, 60.89, 55.95, 55.15, 37.25, 26.86; HRMS
(ES+) m/z found 354.1466; C21H22O5 (M+) requires 354.1467.
(E)-1-(3,4,5-Trimethoxybenzylidene)-7-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (22c). Yield 53%, yellow crystal. Mp:
1
120−123 °C. HPLC: 99.2%. H NMR (300 MHz, CDCl3) δ 7.56 (s,
1H), 7.04−7.10 (m, 2H), 6.78 (d, J = 8.7 Hz, 1H), 6.69 (s, 2H), 3.90
(s, 6H), 3.69 (s, 6H), 3.08 (t, J = 6.3 Hz, 2H), 2.57 (t, J = 6.3 Hz, 2H);
13C NMR (300 MHz, CDCl3) δ 202.17, 156.17, 152.84, 138.92,
135.26, 133.93, 133.22, 130.10, 127.15, 126.27, 121.63, 109.65, 107.22,
60.93, 55.94, 55.54, 36.52, 19.32; HRMS (ES+) m/z found 354.1469;
C21H22O5(M+) requires 354.1467.
Molecular Docking. The X-ray structure of the DAMA−colchicine−
tubulin complex (PDB code 1SA0) was used as the tubulin protein
template. All calculations were performed on an Origin 300 server.
Docking was carried out with AutoDock program. A grid of 45 × 40 × 40
was used to ensure that the area probed was adequate for the ligands
to explore all possible binding modes. Docking runs were performed
using the Larmarckian genetic algorithm (LGA) with some modifica-
tions of the docking parameters. Each docking experiment was derived
from 50 different runs that was set to terminate after a maximum of 10
000 000 energy evaluations or 370 000 generations, yielding 50 docked
conformations. At the end of a docking job with multiple runs,
(E)-1-(2,3,4-Trimethoxybenzylidene)-5-methoxy-3,4-dihy-
dronaphthalen-2(1H)-one (23a). Yield 50%, yellow crystal. Mp:
1
118−120 °C. HPLC: 96.5%. H NMR (300 MHz, CDCl3) δ 7.84 (s,
1H), 7.16 (d, J = 8.4 Hz, 1H), 7.06 (d, J = 9 Hz, 1H), 6.89 (d, J = 2.4
Hz, 1H), 6.75 (dd, J = 8.7, 2.7 Hz, 1H), 6.50 (d, J = 8.7 Hz, 1H), 3.92
(s, 3H), 3.88 (s, 3H), 3.85 (s, 3H), 3.53 (s, 3H), 2.97 (t, J = 6.3 Hz,
2H), 2.62 (t, J = 6.3 Hz, 2H); 13C NMR (300 MHz, CDCl3) δ 201.09,
157.47, 154.61, 153.49, 142.15, 134.05, 132.78, 131.26, 130.61, 128.73,
124.33, 121.93, 114.43, 113.16, 106.87, 61.45, 60.93, 55.99, 55.04,
37.57, 26.99; HRMS (ES+) m/z found 354.1464; C21H22O5(M+)
requires 354.1467.
5730
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Article
AutoDock performed cluster analysis. Docking solutions with ligand
all-atom rmsd values within 0.5 Å of each other were clustered
together and ranked by the lowest energy representative. Low energy
binding modes and the lowest energy conformation from clusters of
five or more occurrences were selected for further refinement. These
were then refined by SYBYL, with the binding mode that had the
lowest complex energy after minimization being selected as the final
binding mode.
X-ray Crystallography. Crystal data for 22b are as follows:
C21H22O5, MW 354.39; crystal size, 0.06 × 0.05 × 0.04 mm3; yellow,
prism; space group P2(1)/c; monoclinic, a = 11.13(3) Å, b = 12.69(3) Å,
c = 14.47(3) Å, α = γ = 90°, β = 111.59(3) °; V = 1900(8) Å; Z = 4;
Dc = 1.239 g/cm3; F(000) = 752; m = 0.088 mm−1; range for data
collection, 2.53−26.16; reflections collected 6490; unique reflections
3326 [Rint = 0.1003]; data/restraints/parameters 3326/0/240; good-
ness-of-fit on F2 1.056; R indices (all data), R1 = 0.0824, wR2 =
0.1960; final R indices [I > 2σ(I)], R1 = 0.0628, wR2 = 0.1785;
CCDC, 761109.
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AUTHOR INFORMATION
■
Corresponding Author
*For C.-H.Z.: phone, +86 021 81871240; e-mail, canhui_
zheng@yahoo.com.cn. For J.-G.L.: phone, +86 021 81871234;
e-mail, ljg20060508@yahoo.com.cn. For Y.-J.Z.: phone, +86
021 81871231; e-mail, zhouyoujun2006@yahoo.com.cn.
(14) Hori, K.; Saito, S. Microvascular mechanisms by which the
combretastatin A-4 derivative AC7700 (AVE8062) induces tumour
blood flow stasis. Br. J. Cancer 2003, 89, 1334−1344.
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of combretastatin A-4 derivatives as anticancer agents. Curr. Med.
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(16) Theeramunkong, S.; Caldarelli, A.; Massarotti, A.; Aprile, S.;
Caprioglio, D.; Zaninetti, R.; Teruggi, A.; Pirali, T.; Grosa, G.; Tron,
G. C.; Genazzani, A. A. Regioselective Suzuki coupling of dihalo-
heteroaromatic compounds as a rapid strategy to synthesize potent
rigid combretastatin analogues. J. Med. Chem. 2011, 54, 4977−4986.
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Author Contributions
†These authors contributed equally to this work.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The work was supported by National Natural Science
Foundation of China (Grant No. 21172260), the Key Program
for Basic Research of Shanghai “Technology Innovation Action
Plan” (Grant No. 09JC1417500), Shanghai Natural Science
Foundation (Grant No. 09ZR1438800), and National Natural
Science Foundation of China (Grant No. 30901859).
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vitro antitumor activity of new 1,4-diarylimidazole-2-ones and their
2-thione analogues. Bioorg. Med. Chem. Lett. 2008, 18, 989−993.
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ABBREVIATIONS USED
■
VDA, vascular disrupting agent; CA-4, combretastatin A-4; CA-
4P, combretastatin A-4 phosphate; CSI, colchicine site
inhibitor; TLC, thin layer chromatography; MTT, 3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; PIPES,
piperazine-N,N′-bis[2-ethanesulfonic acid]sequisodium salt;
EGTA, ethylene glycol bis(2-aminoethyl ether)-N,N,N′,N′-
tetraacetic acid; WBC, white blood cell; LY, lymphocyte;
PLT, platelet; ALT, alanine transaminase; ALP, alkaline
phosphatase
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