Design, synthesis and biological evaluation of a series of pyrano chalcone derivatives containing indole moiety as novel anti-tubulin agents

Article abstract of DOI:10.1016/j.bmc.2014.02.028

A new series of pyrano chalcone derivatives containing indole moiety (3-42, 49a-49r) were synthesized and evaluated for their antiproliferative activities. Among all the compounds, compound 49b with a propionyloxy group at the 4-position of the left phenyl ring and N-methyl-5-indoly on the right ring displayed the most potent cytotoxic activity against all tested cancer cell lines including multidrug resistant phenotype, which inhibits cancer cell growth with IC₅₀ values ranging from 0.22 to 1.80 μM. Furthermore, 49b significantly induced cell cycle arrest in G2/M phase and inhibited the polymerization of tubulin. Molecular docking analysis demonstrated the interaction of 49b at the colchicine binding site of tubulin. In experiments in vivo, 49b exerted potent anticancer activity in HepG2 human liver carcinoma in BALB/c nude mice. These results indicated these compounds are promising inhibitors of tubulin polymerization for the potential treatment of cancer.

Full text of DOI:10.1016/j.bmc.2014.02.028

Bioorganic & Medicinal Chemistry 22 (2014) 2060–2079
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Design, synthesis and biological evaluation of a series of pyrano
chalcone derivatives containing indole moiety as novel anti-tubulin
agents
Guangcheng Wang a, , Chunyan Li a, , Lin He a, Kai Lei a, Fang Wang a, Yuzi Pu a, Zhuang Yang a,b
,
Dong Cao a, Liang Ma a, Jinying Chen a, Yun Sang a,b, Xiaolin Liang a, Mingli Xiang a, Aihua Peng a,
Yuquan Wei a, Lijuan Chen a,
⇑
a State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Keyuan Road 4, Gaopeng Street, Chengdu 610041, China
b College of Chemistry of Sichuan University, Chengdu 610064, Sichuan, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A new series of pyrano chalcone derivatives containing indole moiety (3–42, 49a–49r) were synthesized
and evaluated for their antiproliferative activities. Among all the compounds, compound 49b with a pro-
pionyloxy group at the 4-position of the left phenyl ring and N-methyl-5-indoly on the right ring dis-
played the most potent cytotoxic activity against all tested cancer cell lines including multidrug
Received 9 December 2013
Revised 19 February 2014
Accepted 22 February 2014
Available online 1 March 2014
resistant phenotype, which inhibits cancer cell growth with IC50 values ranging from 0.22 to 1.80 lM.
Furthermore, 49b significantly induced cell cycle arrest in G2/M phase and inhibited the polymerization
of tubulin. Molecular docking analysis demonstrated the interaction of 49b at the colchicine binding site
of tubulin. In experiments in vivo, 49b exerted potent anticancer activity in HepG2 human liver carci-
noma in BALB/c nude mice. These results indicated these compounds are promising inhibitors of tubulin
polymerization for the potential treatment of cancer.
Keywords:
Millepachine
Indole
Chalcone
Tubulin
Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction
indole moiety emerged as a versatile molecular skeleton for the
development of compounds with antitubulin activity.14,15 Over
Microtubules are essential cytoskeletal polymers in all eukary-
otic cells controlling various cellular functions, including cell sig-
naling, cell division, secretion, cell architecture in interphase, and
intracellular transport1–3 and are recognized as important targets
for the development of compounds useful in anticancer chemo-
therapy. The three characterized binding sites of tubulin are the
taxane,4 vinca alkaloid5 and colchicine sites.6 Anti-mitotic com-
pounds such as taxanes and vinca alkaloids have been widely used
in the clinical treatment of different human cancers over the past
decade.7 However, the development of drug resistance, side effects,
complex synthesis, and low bioavailability render these drugs sub-
optimum for clinical treatment of cancer.8 This has encouraged sci-
entists and industry to develop novel antimitotic agents for cancer
therapy.
the last few years, numbers of tubulin polymerization inhibitors
containing indole moiety have been obtained from natural sources
or have been prepared by chemical synthesis. Among them, vin-
blastine16 and vincristine,16 which have been used in clinical and
indibulin,17 MKC-118 and LP-261,19 which are in clinical trials
showed good antiproliferative activities (Fig. 1).
Recently, we have reported the synthesis and biological evalua-
tion of three different series of pyrano chalcone derivatives,20–22
based on the molecular skeleton of nature occurring pyrano chal-
cone millepachine which isolated from Millettia pachycarpa for
the first time in our group.23 These compounds strongly inhibited
the growth of cancer cell lines and tubulin polymerization by bind-
ing to the colchicine site of tubulin and caused cells to arrest in the
G2/M phase of the cell cycle. As a part of our search for novel tubu-
lin polymerization inhibitors, these encouraging results prompted
us to synthesize a new series of pyrano chalcone derivatives
containing indole moiety.
Indole-based derivatives have been found to exhibit a variety of
biological activities such as antiproliferative,9 anti-inflammatory,10
antimalarial,11 anti-bacterial,12 and antifungal activities.13 The
In the present investigation, a new series of pyrano chalcone
derivatives containing indole moiety (3–42, 49a–49r) were synthe-
sized and evaluated for their cytotoxic activities. Among all the
compounds, compound 49b displayed the most potent cytotoxic
⇑
Corresponding author. Tel.: +86 28 85164063; fax: +86 28 85164060.
E-mail address: chenlijuan125@163.com (L. Chen).
These authors contributed equally to this work.
http://dx.doi.org/10.1016/j.bmc.2014.02.028
0968-0896/Ó 2014 Elsevier Ltd. All rights reserved.

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2061
Figure 1. Structures of some indole-based molecules as anti-tubulin agents.
activity against all tested cancer cell lines including multidrug
resistant phenotype, which inhibits cancer cell growth with IC50
values ranging from 0.22 to 1.80 lM. Furthermore, 49b signifi-
cantly induced cell cycle arrest in G2/M phase and inhibit the poly-
merization of tubulin. Molecular docking analysis demonstrated
the interaction of compound 49b at the colchicine binding site of
tubulin.
smoothly to afforded 1,1-dimethylpropargyl ether 1 in good yield,
which, upon heating in pyridine at 120 °C for overnight, underwent
Claisen rearrangement, leading to key intermediate 2. Having
appropriate quantities intermediate 2, we focus on the synthesis
of N-alkyl indole aldehydes 7a–42a, which were synthesized, in
moderate to good yields, by heating indole aldehydes with various
alkyl halides in the presence of Cs2CO3 in CH3CN. Condensation of 2
and N–H indole aldehydes or N-alkyl indole aldehydes 7a–42a
under Claisen–Schmidt conditions using 50% KOH in methanol
provided the desired compounds 3–42.
2. Chemistry
Compounds 49a–49r were synthesized by the method shown in
Scheme 2. The 4-hydroxyl of 1-(2,4-dihydroxyphenyl)ethanone 43
was protected with 3,4-dihydro-2H-Pyran in dichloromethane in
the presence of pyridinium p-toluenesulfonate (PPTS) to give the
Pyrano chalcone derivatives containing indole moiety 3–42
were prepared by the synthetic route outlined in Scheme 1.
Treatment of paeonol with 3-chloro-3-methyl-1-butyne in the
presence of DBU and catalytic amounts of CuCl2ÁH2O proceeded
Scheme 1. Reagents and conditions: (a) DBU, CuCl2ÁH2O, CH3CN, 0 °C, 5 h; (b) pyridine, 120 °C, 12 h; (c) Cs2CO3, CH3CN, 60 °C, 2 h; (d) KOH, methanol, 48 h, room
temperature.

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
THP ether 44, which condensation with 3-chloro-3-methyl-1-bu-
tyne in the presence of DBU and catalytic amounts of CuCl2ÁH2O
provided the 1,1-dimethylpropargyl ether 45, The crude 45 was
directly heating in pyridine at 120 °C for overnight, underwent
Claisen rearrangement, leading to key intermediate 46. Condensa-
tion of 46 and 1-methyl-1H-indole-5-carbaldehyde 31a under
Claisen–Schmidt conditions using 50% KOH in methanol provided
the desired compound 47. Deprotection of the THP groups using
p-toluenesulfonic acid in CH3OH–THF (1:1) solution at 60 °C for
5 h yielded key intermediate 48, followed by an esterification or
etherification of the liberated phenol with acid anhydride, alkyl
halide and sulfonyl halide to afford the final desired products
49a–49r.
the substitutions at the N1-position of 5-indole ring influences cell
growth inhibitory activities. On the basis of these results, the
N-methyl-5-indoly ring seems to be the optimal group on the right
ring.
To understand the effect of substituents at the C-4 position of
the left phenyl ring, compounds 49a–49r were prepared and eval-
uated for their antiproliferative activities. As shown in Table 2,
introduction ester groups (49a–49d), alkoxy groups (49e–49j) or
sulfonate ester groups (49k–49r) at the C-5 position, resulted in
slightly increase of cytotoxicity. Among all the compounds, com-
pound 49b with a propionyloxy group at the 4-position of the left
phenyl ring displayed the most potent cytotoxic activity.
To further evaluate the antiproliferative properties, the most
potent compound 49b was chosen to be further evaluated by
MTT assay against various tumor cell lines (SMMC-7221, HepG2,
PC-3, A549, K562, HCT116, SKOV3 and MCF-7), vincristine
resistant HCT-8 (HCT-8/V), taxol resistant HCT-8 (HCT-8/T) and
normal human cell line (LO2). The results were presented in
Table 3. Compound 49b showed strong antiproliferative activity
3. Results and discussion
3.1. Antiproliferative activity in vitro
The synthesized pyrano chalcone derivatives 3–42 were evalu-
ated for their antiproliferative activities against human hepatocel-
lular liver carcinoma cell line HepG2, which has widely been used
for the screening of potential antitumor compounds, by using MTT
method. Millepachine was chosen as reference molecules. The
compounds that exhibit IC50 > 10.0 lM are considered to be
inactive on the respective cancer cell lines. The cytotoxicities were
expressed as IC50 values presented in Table 1.
With respect to the study of structure–activity relationship
(SAR), we first evaluated the effect of the position of the indole ring
and the N1-substitution group on the indole ring for cytotoxic
activity. Date from cytotoxicity assay of compounds 3–42
with IC50 values in the range of 0.22–1.80 lM against all tested
cancer cell lines and low cytotoxicity on normal human cell line
(LO2).
Although many anticancer drugs in clinical use are effective,
their potentials are limited by the development of drug resis-
tance. Multiple drug resistance cell lines have been reported over-
expression of transmembrane cellular pumps P-glycoprotein
(Pgp).24 To investigate whether these derivatives are substrates
of P-glycoprotein, the antiproliferative activity of 49b against tu-
mor cell lines with different resistance phenotypes was evaluated
by MTT assay. As showed in Table 3, 49b was effective against the
tested cell lines and retained activity in cell lines with various
multiple drug resistance phenotypes. These results indicating that
this type of compound has great potential to overcome resistance
to anti-tubulin drugs.
suggested that
position of the indole ring resulted in the best activity. Shifting
,b-unsaturated ketone group to the C-4 or C-6 position resulted
a,b-unsaturated ketone located at the C-3, or C-5
a
in moderate activity, while changing to the C-7 position decreased
the activity drastically. It is interesting to point out that compound
31, with a N1-methyl group, displayed the most potent antiprolif-
3.2. Tubulin polymerization assay
erative activity with an IC50 value of 0.84 lM. However, compound
To investigate whether the antiproliferative activities of these
compounds were related to the interaction with the microtubule
system, the effect of compound 49b on the polymerization of
4, with a N1–H group, slightly decrease of cytotoxicity, but increase
in the bulkiness of the substituent (32) resulted in a remarkable
decrease of cytotoxicity, thus revealing that the steric effect of
Scheme 2. Reagents and conditions: (a) DHP, PPTS, CH2Cl2, 5 h, room temperature; (b) DBU, CuCl2ÁH2O, CH3CN, 0 °C, 5 h; (c) pyridine, 120 °C, 12 h; (d) KOH, methanol, 48 h,
room temperature; (e) TsOH, THF–CH3OH = 1:1, 60 °C, 5 h; (f) compounds 49a–49e: pyridine, 12 h, room temperature; compounds 49f–49j: Cs2CO3, acetone, 12 h, room
temperature; compounds 49k–49r: Cs2CO3, acetone, 12 h, room temperature.

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
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Table 1
Table 2
The in vitro antiproliferative activities of pyrano chalcone derivatives 3–42 and
The in vitro antiproliferative activities of pyrano chalcone derivatives 49a–49r against
millepachine against human cancer cell lines HepG2
human cancer cell lines HepG2
O
O
O
O
R2
N
O
O
N
R1
49a-49r
3-43
Compound
R2
Acetyl
Propionyl
Isobutyryl
Pentanoyl
Ethyl
Isopropyl
n-Propyl
n-Butyl
IC50 (lM)
Compound
R1
Indole position
IC50 (lM)
49a
49b
49c
49d
49e
49f
49g
49h
49i
49j
49k
49l
49m
49n
49o
49p
49q
49r
0.52 0.05
0.22 0.03
0.37 0.04
0.92 0.08
0.75 0.10
0.78 0.03
0.46 0.05
0.63 0.02
0.67 0.06
0.97 0.04
0.69 0.05
0.62 0.03
1.53 0.12
0.86 0.05
0.75 0.03
1.87 0.22
1.55 0.03
0.57 0.04
Millepachine
3
4
5
6
7
8
9
1.51 0.03
8.38 0.04
1.06 0.02
4.95 0.02
7.62 0.03
4.70 0.05
2.23 0.04
3.01 0.02
>10.0
2.81 0.22
3.23 0.06
1.78 0.02
2.75 0.02
3.09 0.04
>10.0
H
H
H
H
4
5
6
7
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
5
5
6
6
6
6
6
7
7
7
7
7
Methoxymethyl
Methyl
Ethyl
Isobutyl
Prenyl
2-Morpholinoethyl
Benzyl
2-Fluorobenzyl
3-Fluorobenzyl
4-Fluorobenzyl
2-Chlorobenzyl
3-Chlorobenzyl
4-Chlorobenzyl
2-Bromobenzyl
3-Bromobenzyl
4-Bromobenzyl
2-Trifluoromethylbenzyl
3-Trifluoromethylbenzyl
4-Trifluoromethylbenzyl
Methyl
n-Amyl
Isobutyl
3,5-Difluorobenzenesulfonyl
4-Bromo-2-(trifluoromethyl)benzenesulfonyl
2,3,4,5,6-Pentafluorobenzenesulfonyl
4-Methylbenzenesulfonyl
3-Methoxybenzenesulfonyl
4-Isopropylbenzenesulfonyl
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
1.94 0.04
2.13 0.03
>10.0
>10.0
1.38 0.04
>10.0
3-(Trifluoromethyl)benzenesulfonyl
2-Methoxy-4-nitrobenzenesulfonyl
Table 3
>10.0
The in vitro antiproliferative activities of selected compound 49b against various
human tumor cell lines and normal human liver cell line LO2
2.18 0.02
3.46 0.08
2.75 0.03
5.54 0.04
>10.0
>10.0
>10.0
0.84 0.12
4.45 0.05
8.85 0.06
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
Cell lines
Liver
IC50 (lM)
Ethyl
3-Fluorobenzyl
3-Chlorobenzyl
3-Bromobenzyl
Methyl
2-(Piperidin-1-yl)ethyl
Methyl
SMMC-7221
HepG2
1.8 0.04
0.22 0.03
Prostate
Lung
Leukemia
Colon
Ovarian
Breast
PC-3
A549
K562
HCT116
SKOV3
MCF-7
0.65 0.01
0.68 0.01
0.8 0.01
1.28 0.01
0.23 0.04
1.5 0.02
Ethyl
3-Fluorobenzyl
3-Chlorobenzyl
3-Bromobenzyl
Methyl
Drug resistant
HCT-8/T
HCT-8/V
1.6 0.04
0.45 0.02
Ethyl
Normal
LO2
>10.0
3-Fluorobenzyl
3-Chlorobenzyl
3-Bromobenzyl
tions of 0.125
lM, 0.25
lM, 0.375
l
M and 0.50
l
M, respectively. In
control (untreated cells) 25.5% of accumulation in G2/M phase was
observed. These results clearly demonstrated that 49b could arrest
cells in G2/M phase in a dose-dependent manner, which is consis-
tent with the behavior of tubulin-binding agents.
purified tubulin was evaluated at a concentration of 10.0
lM. Col-
chicine (2.5 M) and paclitaxel (2.5 M) were used as a reference.
l
l
Figure 2 shows that compound 49b proved to be a strong inhibitor
of tubulin polymerization and indicates the rational relationship
between the inhibition of tubulin and the corresponding antiprolif-
erative activity. The results demonstrated that tubulin is a possible
target for these compounds.
3.4. Effects on apoptosis
Cell-cycle arrest in the G2/M phase is frequently followed by
DNA fragmentation and other morphological features of apoptosis.
To determine whether compound 49b exhibiting high antitumor
activity induce apoptosis of HepG2 cells, the potency of 49b to
induce apoptosis was further characterized by apoptosis assay.
3.3. Cell cycle analysis
Because the anti-mitotic drugs induced cell cycle arrest at G2/M
phase in various cancer cell lines and led to an increment of the rel-
ative peak in the DNA histogram.25,26 The effect of the most active
compound 49b on cell cycle progression was investigated in
HepG2 (human hepatocellular liver carcinoma) cells by flow
cytometry at various concentrations. As shown in Figure 3, the per-
centage of cells in the G2/M phase were 26.2%, 60.7%, 75.0% and
86.0% when the cells were treated with 49b for 24 h at concentra-
HepG2 cells were treated with 0.125
lM, 0.25 lM, 0.375 lM and
0.50 M of 49b for 48 h. As shown in Figure 4, the results showed
l
that the effect was observed in a dose-dependent manner and the
apoptotic rates of HepG2 cells increased with the increase of
concentration of 49b. The results demonstrated that 49b, in addi-
tion to its antiproliferative properties, also induced apoptosis in
the tested cancer cell lines.

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
3.7. In vivo antitumor activity of compound 49b
To further evaluate the antitumor effect of 49b in vivo, we per-
formed an animal study using a hepatocarcinoma HepG2 mice
model. As shown in Figure 7, the results demonstrated that the
growth of tumors in mice treated with 49b (30 mg/kg) was
reduced by 56.58% compared with that in control mice treated
with vehicle only at day 35. By comparison, positive control anti-
cancer drug 5-Fu reduced the growth of tumors by 25.93%. Mean-
while, we did not observe significant growth inhibition of mice in
the 49b and 5-Fu treated groups compared to the vehicle group.
These results indicated that 49b had a significant in vivo antitumor
activity in mice, with little effect on the normal growth of the
animals.
4. Conclusions
In conclusion, the synthesis and biological evaluation of a series
of pyrano chalcone derivatives containing indole moiety was
discussed. Most of these synthesized compounds showed
moderate to potent cytotoxic activity against HepG2 cancer cell
lines. The SAR study demonstrated that N-methyl-5-indoly on right
ring and propionyloxy group at the 4-position of the left phenyl
ring had beneficial effect on the cytotoxicity activity. Flow cytom-
etry analysis and Immunofluorenscence staining assay showed
that compound 49b led to cell cycle arrest at the G2/M phase by
effectively inhibit microtubule polymerization. Finally, molecular
docking analysis demonstrated the interaction of 49b at the
colchicine binding site of tubulin. These results indicated pyrano
chalcone derivatives containing indole moiety are promising
inhibitors of tubulin polymerization for the potential treatment
of cancer.
Figure 2. Effects of 49b on in vitro tubulin polymerization assay. Purified tubulin of
rat and ATP were mixed in a 96-well plate. The reaction was started by warming the
solution from 4 to 37 °C. Colchicine (2.5 lM) and paclitaxel (2.5 lM) were used as a
reference, while DMSO (0.1% v/v) was used as a vehicle control. The effect on
tubulin assembly was monitored in a Spectramax M5 Microtiter Plate Luminometer
(Molecular Devices, USA) at 350 nm at 60 s intervals for 60 min at 37 °C.
3.5. Immunofluorenscence staining
Accumulative evidence showed that microtubule-targeting
drugs disrupt the cellular microtubule network and formation of
the mitotic spindle, subsequently resulting in the blockage of the
cell cycle in G2/M phase.27 In order to confirm the antiproliferative
activity of 49b derived from an interaction with tubulin, we inves-
tigated microtubule structure in human hepatocellular liver carci-
noma cell line HepG2 exposed to 49b by immunofluorescence
5. Experimental section
5.1. Chemistry
using a-tubulin monoclonal antibody. As shown in Figure 5, in con-
All starting materials and reagents were purchased from com-
mercial suppliers. TLC was performed on 0.20 mm Silica Gel 60
F254 plates (Qingdao Ocean Chemical Factory, Shandong, China).
Nuclear magnetic resonance spectra (NMR) were recorded at
400 MHz on a Varian spectrometer (Varian, Palo Alto, CA) and
reported in parts per million. Mass spectra (MS) were measured
by Q-TOF Priemier mass spectrometer (Micromass, Manchester,
UK).
trol cells, we observed a well-organized microtubule network
throughout the cells. However, cells treatment with 49b showed
disrupted microtubule organization. These results confirm that
tubulin is an effective target for its anti-tumor activity.
3.6. Docking study
To further elucidate the interactions between compound 49b
and tubulin, a molecular docking study was performed by simula-
tion of compound 49b into the colchicine binding site of tubulin.
The molecular docking study was carried out by genetic optimiza-
tion of ligand docking (GOLD)28 that docks flexible ligands into
protein binding sites. The 3D structure of tubulin was gained from
Protein Data Bank (PDB ID: 3N2G).29 All water molecules were
deleted, and Charmm force field was assigned by using Accelrys
Discovery Studio 3.1. The binding site was defined as a sphere con-
taining the residues within 10 Å from the ligand. The Goldscore
was used as fitness function. And the rest parameters were kept
at their default values. The results of the molecular docking study
are summarized in Figure 6. The binding site of tubulin is a semi-
enclosed pocket. N-methyl indole moiety of the compound 49b is
surrounded by residues Tyr52, Gln136, Glu200, Tyr202, Val238
and Ile378 which form a hydrophobic domain. Residues Thr179,
Ala180, Ala250, Leu255, Asn258, Ala316, Val318, Lys352 and
Ala354 form a polar domain, which locate the other part of the
compound 49b of which the oxygen atom connecting with benzo-
pyran ring can form a hydrogen bond with the hydroxyl group of
Thr179. Overall, the result of the molecular docking study sug-
gested that compound 49b was a potential inhibitor of tubulin.
5.1.1. 1-(4-Methoxy-2-((2-methylbut-3-yn-2-yl)oxy)phenyl)
ethanone (1)
To
a solution of 1-(2-hydroxy-4-methoxyphenyl)ethanone
(1.66 g, 10 mmol) in CH3CN (100 mL) at 0 °C was added DBU
(1.5 mL, 15 mmol), CuCl2ÁH2O (5 mg, 0.3% mol), and 3-chloro-3-
methyl-1-butyne (1.53 g, 15 mmol). The mixture was stirred at
0 °C for 5 h and monitored by TLC. After completed, 1 N HCl (aq)
was added to adjust pH = 2. After removing the solvent under
reduced pressure, the residue was poured into water (50 mL) and
the white precipitate was collected by filtration to obtain 1
(1.97 g, 85%). 1H NMR (CDCl3, 400 MHz) d: 1.75 (s, 6H), 2.58 (s,
3H), 2.69 (s, 1H), 3.84 (s, 3H), 6.58 (dd, 1H, J = 8.8 Hz, 2.0 Hz),
7.19 (d, 1H, J = 2.0 Hz), 7.75 (d, 1H, J = 8.8 Hz); MS (ESI, m/z):
255.05 [M+Na]+.
5.1.2. 1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)ethanone
(2)
A suspension of 1 (2.32 g, 10 mmol) in pyridine (50 mL) was
stirred at 120 °C for 12 h. After cooling to room temperature, the
mixture concentrated under reduced pressure to give 2 as black

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2065
Figure 3. Flow cytometry analysis of compound 49b in HepG2 cells. (A) Cell cycle distribution of HepG2 cells after treatment with 49b at different concentrations (0.125
0.25 M, 0.375 M and 0.50 M) for 24 h. An increased proportion of cells at G2/M phase were observed in cells treated with 49b. (B) The statistical graph of cell cycle
distribution.
lM,
l
l
l
oil, which was used in the next step without further purification.
1H NMR (CDCl3, 400 MHz) d: 1.49 (s, 6H), 2.62 (s, 3H), 3.87 (s,
3H), 5.61 (d, 1H, J = 10.0 Hz), 6.47 (d, 1H, J = 8.8 Hz), 6.66 (d, 1H,
J = 10.0 Hz), 7.73 (d, 1H, J = 8.8 Hz); MS (ESI, m/z): 255.14 [M+Na]+.
5.1.3. General procedure A for the synthesis of 7a–42a
To a solution of indole-aldehyde (435 mg 3 mmol) in CH3CN
(30 mL) was added Cs2CO3 (829 mg, 6 mmol), and the mixture
was refluxed for 2 h. To this solution, alkyl halide (3.3 mmol) was

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
Figure 4. Apoptotic effects of 49b in HepG2 cells. (A) The results are expressed in the percentage of apoptotic cells detected following 48 h of treatment with 49b at different
concentrations (0.125 M, 0.25 M, 0.375 M and 0.50 M). (B) The rate of apoptotic cells as detected by flow cytometry.
l
l
l
l
added, and the mixture was heated under reflux for 1 h. After the
completion of the reaction, the solvent was evaporated under re-
duced pressure and water was added to the reaction mixture and
extracted 3 times for ethyl acetate. The combined organic layers
were dried over Na2SO4 and concentrated under vacuum. The res-
idue was purified by flash chromatography.
400 MHz) d: 1.55 (t, 3H, J = 7.2 Hz), 4.20 (q, 2H, J = 7.2 Hz),
7.26–7.34 (m, 2H), 7.38 (t, 1H, J = 7.2 Hz), 7.74 (s, 1H), 8.30 (d,
1H, J = 8.0 Hz), 10.0 (s, 1H); MS (ESI, m/z): 196.1 [M+Na]+.
5.1.3.4. 1-Isopropyl-1H-indole-3-carbaldehyde (10a). The com-
pound 10a was prepared from indole-3-aldehyde and 2-iodopro-
pane according to general procedure A. The residue was purified
by flash chromatography to give 387 mg (69%) of product. 1H
NMR (CDCl3, 400 MHz) d: 1.57 (d, 6H, J = 6.8 Hz), 4.69 (heptet, 1H,
J = 6.8 Hz), 7.28–7.35 (m, 2H), 7.40 (d, 1H, J = 8.0 Hz), 7.84 (s, 1H),
8.31 (d, 1H, J = 7.2 Hz), 10.0 (s, 1H); MS (ESI, m/z): 210.1 [M+Na]+.
5.1.3.1. 1-(Methoxymethyl)-1H-indole-3-carbaldehyde (7a). The
compound 7a was prepared from indole-3-aldehyde and chloro
(methoxy)methane according to general procedure A. The residue
was purified by flash chromatography to give 465 mg (82%) of prod-
uct. 1H NMR (CDCl3, 400 MHz) d: 3.30 (s, 3H), 5.50 (s, 2H), 7.33–7.39
(m, 2H), 7.52 (d, 1H, J = 8.0 Hz), 7.80 (s, 1H), 8.31 (d, 1H, J = 7.2 Hz),
10.05 (s, 1H); MS (ESI, m/z): 212.2 [M+Na]+.
5.1.3.5.
1-(3-Methylbut-2-en-1-yl)-1H-indole-3-carbaldehyde
(11a). The compound 11a was prepared from indole-3-aldehyde
and 1-bromo-3-methylbut-2-ene according to general procedure
A. The residue was purified by flash chromatography to give
371 mg (58%) of product. 1H NMR (CDCl3, 400 MHz) d: 1.82 (s,
3H), 1.84 (s, 3H), 4.71 (d, 2H, J = 7.2 Hz), 5.42 (t, 1H, J = 7.2 Hz),
7.29–7.38 (m, 3H), 7.72 (s, 1H), 8.29 (d, 1H, J = 8.0 Hz), 9.97 (s,
1H); MS (ESI, m/z): 236.1 [M+Na]+.
5.1.3.2. 1-Methyl-1H-indole-3-carbaldehyde (8a). The com-
pound 8a was prepared from indole-3-aldehyde and iodomethane
according to general procedure A. The residue was purified by flash
chromatography to give 358 mg (75%) of product. 1H NMR (CDCl3,
400 MHz) d: 3.76 (s, 3H), 7.27–7.30 (m, 3H), 7.55–7.57 (m, 1H),
8.26–8.28 (m, 1H), 9.88 (s, 1H); MS (ESI, m/z): 182.2 [M+Na]+.
5.1.3.6.
1-(2-Morpholinoethyl)-1H-indole-3-carbaldehyde
(12a). The compound 12a was prepared from indole-3-aldehyde
and 4-(2-chloroethyl)morpholine hydrochloride according to gen-
eral procedure A. The residue was purified by flash chromatogra-
phy to give 379 mg (49%) of product. 1H NMR (CDCl3, 400 MHz)
d: 2.49 (t, 4H, J = 4.4 Hz), 2.80 (t, 2H, J = 6.4 Hz), 3.70 (t, 4H,
5.1.3.3. 1-Ethyl-1H-indole-3-carbaldehyde (9a). The compound
9a was prepared from indole-3-aldehyde and iodoethane
according to general procedure A. The residue was purified by flash
chromatography to give 442 mg (85%) of product. 1H NMR (CDCl3,

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2067
Figure 5. Effect of 49b on the organization of cellular microtubule network. HepG2 cells treated with 49b were fixed and stained with
a
-tubulin, and then counterstained
with 4,6-diamidino-2-phenylindole (DAPI). Microtubules and unassembled tubulin are shown in green. DNA, stained with DAPI, is shown in blue.
Figure 6. The interaction mode of compound 49b within the binding site of tubulin (PDB ID: 3N2G). Ligand is represented with thick stick and carbon atoms are depicted
with green color. Residues within the binding site were expressed with thin stick and colored by their types.
J = 4.4 Hz), 4.28 (t, 2H, J = 6.4 Hz), 7.30–7.35 (m, 2H), 7.38 (t, 1H,
J = 7.2 Hz), 7.81 (s, 1H), 8.30 (d, 1H, J = 8.0 Hz), 10.01 (s, 1H); MS
(ESI, m/z): 281.1 [M+Na]+.
was purified by flash chromatography to give 600 mg (85%) of
product. 1H NMR (CDCl3, 400 MHz) d: 5.35 (s, 2H), 7.17 (d, 1H,
J = 7.2 Hz), 7.31–7.35 (m, 6H), 7.70 (s, 1H), 8.32 (d, 1H, J = 7.2 Hz),
10.00 (s, 1H); MS (ESI, m/z): 258.1 [M+Na]+.
5.1.3.7. 1-Benzyl-1H-indole-3-carbaldehyde (13a). The com-
pound 13a was prepared from indole-3-aldehyde and (bromo-
methyl)benzene according to general procedure A. The residue
5.1.3.8.
1-(2-Fluorobenzyl)-1H-indole-3-carbaldehyde
(14a). The compound 14a was prepared from indole-3-aldehyde

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
Figure 7. The in vivo antitumor activity of compound 49b against HepG2 xenografts in BALB/c nude mice. (A) The curves of inhibition of tumors. HepG2 tumor-bearing nude
mice were administered vehicle alone, or 15 mg/kg or 30 mg/kg of 49b once every two days for 21 days, the positive group received injections of 5-Fu at a dose of 5 mg/kg
once a day. Each group contained six mice; bars, SD. (B) Effects of 49b and 5-Fu on mice body weight, bars, SD. (C) The picture of the stripping tumor from mice. (D) Effects
of 49b and 5-Fu on tumor weight.⁄P < 0.05, ⁄⁄P < 0.01, and ⁄⁄⁄P < 0.001, significantly different compared with control by t test.
and 1-(bromomethyl)-2-fluorobenzene according to general proce-
dure A. The residue was purified by flash chromatography to give
631 mg (83%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.40 (s,
2H), 7.05–7.15 (m, 4H), 7.27–7.46 (m, 3H), 7.77 (s, 1H), 8.32 (d,
1H, J = 8.0 Hz), 10.01 (s, 1H); MS (ESI, m/z): 254.1 [M+H]+.
5.1.3.12.
1-(3-Chlorobenzyl)-1H-indole-3-carbaldehyde
(18a). The compound 18a was prepared from indole-3-aldehyde
and 1-chloro-3-(chloromethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
574 mg (71%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.33 (s, 2H),
6.09 (d, 2H, J = 8.0 Hz), 7.26–7.32 (m, 5H), 7.70 (s, 1H), 8.31 (d, 1H,
J = 8.8 Hz), 10.00 (s, 1H); MS (ESI, m/z): 292.0 [M+Na]+.
5.1.3.9. 1-(3-Fluorobenzyl)-1H-indole-3-carbaldehyde (15a). The
compound 15a was prepared from indole-3-aldehyde and 1-(bro-
momethyl)-3-fluorobenzene according to general procedure A.
The residue was purified by flash chromatography to give
615 mg (81%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.35 (s,
2H), 6.84 (d, 1H, J = 8.8 Hz), 6.93 (d, 1H, J = 8.0 Hz), 7.01 (t, 1H,
J = 8.0 Hz), 7.27–7.34 (m, 4H), 7.72 (s, 1H), 8.32 (d, 1H, J = 8.0 Hz),
10.02 (s, 1H); MS (ESI, m/z): 276.0 [M+Na]+.
5.1.3.13.
1-(4-Chlorobenzyl)-1H-indole-3-carbaldehyde
(19a). The compound 19a was prepared from indole-3-aldehyde
and 1-chloro-4-(chloromethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
639 mg (79%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.31 (s, 2H),
7.01 (d, 1H, J = 7.2 Hz), 7.17 (s, 1H), 7.24–7.34 (m, 5H), 7.70 (s, 1H),
8.32 (d, 1H, J = 8.8 Hz), 10.00 (s, 1H); MS (ESI, m/z): 292.0 [M+Na]+.
5.1.3.10.
1-(4-Fluorobenzyl)-1H-indole-3-carbaldehyde
(16a). The compound 16a was prepared from indole-3-aldehyde
and 1-(bromomethyl)-4-fluorobenzene according to general proce-
dure A. The residue was purified by flash chromatography to give
577 mg (76%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.33 (s,
2H), 7.04 (t, 2H, J = 8.0 Hz), 7.16 (t, 2H, J = 8.0 Hz), 7.31–7.33 (m,
3H), 7.70 (s, 1H), 8.32 (d, 1H, J = 8.0 Hz), 10.00 (s, 1H); MS (ESI,
m/z): 276.0 [M+Na]+.
5.1.3.14.
1-(2-Bromobenzyl)-1H-indole-3-carbaldehyde
(20a). The compound 20a was prepared from indole-3-aldehyde
and 1-bromo-2-(bromomethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
631 mg (67%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.45 (s, 2H),
6.78 (t, 1H, J = 8.0 Hz), 7.19–7.21 (m, 2H), 7.32–7.36 (m, 3H), 7.65
(t, 1H, J = 8.0 Hz), 7.71 (s, 1H), 8.33 (d, 1H, J = 8.8 Hz), 10.01 (s,
1H); MS (ESI, m/z): 337.0 [M+Na]+.
5.1.3.11.
1-(2-Chlorobenzyl)-1H-indole-3-carbaldehyde
(17a). The compound 17a was prepared from indole-3-aldehyde
and 1-chloro-2-(chloromethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
680 mg (84%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.46 (s, 2H),
6.83 (d, 1H, J = 8.0 Hz), 7.18 (t, 1H, J = 8.0 Hz), 7.27–7.34 (m, 4H),
7.45 (d, 1H, J = 8.0 Hz), 7.72 (s, 1H), 8.33 (d, 1H, J = 8.8 Hz), 10.02
(s, 1H); MS (ESI, m/z): 292.0 [M+Na]+.
5.1.3.15.
1-(3-Bromobenzyl)-1H-indole-3-carbaldehyde
(21a). The compound 21a was prepared from indole-3-aldehyde
and 1-bromo-3-(bromomethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
575 mg (61%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.33 (s, 2H),
7.05 (d, 1H, J = 8.0 Hz), 7.18–7.23 (m, 1H), 7.29–7.35 (m, 4H), 7.45

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2069
(d, 1H, J = 7.2 Hz), 7.72 (s, 1H), 8.32 (d, 1H, J = 8.8 Hz), 10.02 (s, 1H);
MS (ESI, m/z): 337.0 [M+Na]+.
5.1.3.23.
1-(3-Chlorobenzyl)-1H-indole-4-carbaldehyde
(29a). The compound 29a was prepared from indole-4-aldehyde
and 1-chloro-3-(chloromethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
615 mg (76%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.34 (s, 2H),
6.74 (d, 1H, J = 7.8 Hz), 7.08 (s, 1H), 7.19–7.36 (m, 5H), 7.49 (d, 1H,
J = 8.0 Hz), 7.62 (d, 1H, J = 7.2 Hz), 10.24 (s, 1H); MS (ESI, m/z):
292.0 [M+Na]+.
5.1.3.16.
1-(4-Bromobenzyl)-1H-indole-3-carbaldehyde
(22a). The compound 22a was prepared from indole-3-aldehyde
and 1-bromo-4-(bromomethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
726 mg (77%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.30 (s, 2H),
7.02 (d, 2H, J = 8.0 Hz), 7.27–7.34 (m, 3H), 7.45 (d, 2H, J = 8.0 Hz),
7.69 (s, 1H), 8.31 (d, 1H, J = 8.8 Hz), 9.99 (s, 1H); MS (ESI, m/z):
337.0 [M+Na]+.
5.1.3.24.
1-(3-Bromobenzyl)-1H-indole-4-carbaldehyde
(30a). The compound 30a was prepared from indole-4-aldehyde
and 1-bromo-3-(bromomethyl)benzene according to general pro-
cedure A. The residue was purified by flash chromatography to give
622 mg (66%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.34 (s, 2H),
6.95 (d, 1H, J = 7.6 Hz), 7.15 (t, 1H, J = 7.6 Hz), 7.26 (s, 1H), 7.29 (d,
1H, J = 7.6 Hz), 7.33 (s, 1H), 7.36 (s, 1H), 7.39 (d, 1H, J = 8.0 Hz), 7.49
(d, 1H, J = 8.0 Hz), 7.62 (d, 1H, J = 7.2 Hz), 10.24 (s, 1H); MS (ESI, m/
z): 337.0 [M+Na]+.
5.1.3.17. 1-(2-(Trifluoromethyl)benzyl)-1H-indole-3-carbalde-
hyde (23a). The compound 23a was prepared from indole-3-alde-
hyde and 1-(bromomethyl)-2-(trifluoromethyl)benzene according
togeneral procedureA. The residuewas purifiedby flash chromatog-
raphy to give 536 mg (59%) of product. 1H NMR (CDCl3, 400 MHz) d:
5.57 (s, 2H), 6.70 (d, 1H, J = 8.0 Hz), 7.19 (d, 1H, J = 8.0 Hz), 7.25–7.34
(m, 2H), 7.36–7.43 (m, 2H), 7.71 (s, 1H), 7.74 (d, 2H, J = 8.0 Hz), 8.31
(d, 1H, J = 8.8 Hz), 10.01 (s, 1H); MS (ESI, m/z): 326.0 [M+Na]+.
5.1.3.25. 1-Methyl-1H-indole-5-carbaldehyde (31a). The com-
pound 31a was prepared from indole-5-aldehyde and iodometh-
ane according to general procedure A. The residue was purified
by flash chromatography to give 401 mg (84%) of product. 1H
NMR (CDCl3, 400 MHz) d: 3.84 (s, 3H), 6.64 (d, 1H, J = 2.8 Hz),
7.15 (d, 1H, J = 2.8 Hz), 7.39 (d, 1H, J = 8.8 Hz), 7.79 (d, 1H,
J = 8.8 Hz), 8.15 (s, 1H), 10.03 (s, 1H); MS (ESI, m/z): 182.2 [M+Na]+.
5.1.3.18. 1-(3-(Trifluoromethyl)benzyl)-1H-indole-3-carbalde-
hyde (24a). The compound 24a was prepared from indole-3-alde-
hyde and 1-(bromomethyl)-3-(trifluoromethyl)benzene according
togeneral procedureA. The residuewas purifiedby flash chromatog-
raphy to give 573 mg (63%) of product. 1H NMR (CDCl3, 400 MHz) d:
5.43 (s, 2H), 7.26–7.34 (m, 4H), 7.46 (t, 1H, J = 8.0 Hz), 7.51 (s, 1H),
7.59 (d, 1H, J = 8.0 Hz), 7.74 (s, 1H), 8.33 (d, 1H, J = 8.8 Hz), 10.03 (s,
1H); MS (ESI, m/z): 326.1 [M+Na]+.
5.1.3.26. 1-(2-(Piperidin-1-yl)ethyl)-1H-indole-5-carbaldehyde
(32a). The compound 32a was prepared from indole-5-aldehyde
and 1-(2-chloroethyl)piperidine hydrochloride according to gen-
eral procedure A. The residue was purified by flash chromatogra-
phy to give 361 mg (47%) of product. 1H NMR (CDCl3, 400 MHz)
d: 1.44–1.45 (m, 2H), 1.55–1.59 (m, 4H), 2.34–2.50 (m, 4H), 2.70
(t, 2H, J = 6.8 Hz), 4.26 (t, 2H, J = 6.8 Hz), 6.64 (d, 1H, J = 2.4 Hz),
7.25 (d, 1H, J = 2.4 Hz), 7.42 (d, 1H, J = 8.8 Hz), 7.46 (d, 1H,
J = 8.8 Hz), 8.13 (s, 1H), 10.01 (s, 1H); MS (ESI, m/z): 255.4 [MÀH]À.
5.1.3.19. 1-(4-(Trifluoromethyl)benzyl)-1H-indole-3-carbalde-
hyde (25a). The compound 25a was prepared from indole-3-alde-
hyde and 1-(bromomethyl)-4-(trifluoromethyl)benzene according
togeneral procedureA. The residuewas purifiedby flash chromatog-
raphy to give 491 mg (54%) of product. 1H NMR (CDCl3, 400 MHz) d:
5.44 (s, 2H), 7.25–7.29 (m, 3H), 7.30–7.35 (m, 2H), 7.59 (d, 2H,
J = 8.0 Hz), 7.74 (s, 1H), 8.33 (d, 1H, J = 8.8 Hz), 10.03 (s, 1H); MS
(ESI, m/z): 302.3 [MÀH]À.
5.1.3.27. 1-Methyl-1H-indole-6-carbaldehyde (33a). The com-
pound 33a was prepared from indole-6-aldehyde and iodometh-
ane according to general procedure A. The residue was purified
by flash chromatography to give 363 mg (76%) of product. 1H
NMR (CDCl3, 400 MHz) d: 3.88 (s, 3H), 6.56 (d, 1H, J = 2.4 Hz),
7.28 (d, 1H, J = 2.4 Hz), 7.62 (d, 1H, J = 8.0 Hz), 7.70 (d, 1H,
J = 8.0 Hz), 7.90 (s, 1H), 10.07 (s, 1H); MS (ESI, m/z): 182.2 [M+Na]+.
5.1.3.20. 1-Methyl-1H-indole-4-carbaldehyde (26a). The com-
pound 26a was prepared from indole-4-aldehyde and iodometh-
ane according to general procedure A. The residue was purified
by flash chromatography to give 491 mg (70%) of product. 1H
NMR (CDCl3, 400 MHz) d: 3.84 (s, 3H), 7.23–7.26 (m, 2H), 7.34 (t,
1H, J = 8.0 Hz), 7.57 (d, 1H, J = 8.0 Hz), 7.61 (d, 1H, J = 7.2 Hz),
10.23 (s, 1H); MS (ESI, m/z): 182.2 [M+Na]+.
5.1.3.28. 1-Ethyl-1H-indole-6-carbaldehyde (34a). The com-
pound 33a was prepared from indole-6-aldehyde and iodoethane
according to general procedure A. The residue was purified by flash
chromatography to give 379 mg (73%) of product. 1H NMR (CDCl3,
400 MHz) d: 1.49 (t, 3H, J = 7.2 Hz), 4.21 (q, 2H, J = 7.2 Hz), 6.55 (d,
1H, J = 2.4 Hz), 7.33 (d, 1H, J = 2.4 Hz), 7.60 (d, 1H, J = 8.0 Hz), 7.69
(d, 1H, J = 8.0 Hz), 7.91 (s, 1H), 10.05 (s, 1H); MS (ESI, m/z): 196.2
[M+Na]+.
5.1.3.21. 1-Ethyl-1H-indole-4-carbaldehyde (27a). The com-
pound 27a was prepared from indole-4-aldehyde and iodoethane
according to general procedure A. The residue was purified by flash
chromatography to give 405 mg (78%) of product. 1H NMR (CDCl3,
400 MHz) d: 1.48 (t, 3H, J = 7.2 Hz), 4.21 (q, 2H, J = 7.2 Hz),
7.25–7.36 (m, 4H), 7.61 (d, 2H, J = 7.2 Hz), 10.24 (s, 1H); MS (ESI,
m/z): 196.1 [M+Na]+.
5.1.3.29. 1-(3-Fluorobenzyl)-1H-indole-6-carbaldehyde (35a). The
compound 35a was prepared from indole-6-aldehyde and 1-(bromo-
methyl)-3-fluorobenzene according to general procedure A. The residue
was purified by flash chromatography to give 570 mg (75%) of product.
1H NMR (CDCl3, 400 MHz) d: 5.36 (s, 2H), 6.65 (d, 1H, J = 2.4 Hz), 6.96 (d,
1H, J = 6.8 Hz), 7.09 (s, 1H), 7.21–7.29 (m, 2H), 7.33 (d, 1H, J = 2.4 Hz),
7.64 (d, 1H, J = 8.0 Hz), 7.74 (d, 1H, J = 8.0 Hz), 7.81 (s, 1H), 10.01 (s,
1H); MS (ESI, m/z): 276.0 [M+Na]+.
5.1.3.22. 1-(3-Fluorobenzyl)-1H-indole-4-carbaldehyde (28a). The
compound 28a was prepared from indole-4-aldehyde and 1-(bromo-
methyl)-3-fluorobenzene according to general procedure A. The residue
was purified by flash chromatography to give 539 mg (71%) of product.
1H NMR (CDCl3, 400 MHz) d: 5.38 (s, 2H), 6.74 (d, 1H, J = 8.0 Hz), 6.85
(d, 1H, J = 8.0 Hz), 6.96 (t, 1H, J = 8.0 Hz), 7.24–7.36 (m, 4H), 7.50 (d, 1H,
J = 8.0 Hz), 7.63 (d, 1H, J = 7.2 Hz), 10.25 (s, 1H); MS (ESI, m/z): 276.0
[M+Na]+.

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
5.1.3.30. 1-(3-Chlorobenzyl)-1H-indole-6-carbaldehyde (36a). The
compound 36a was prepared from indole-6-aldehyde and 1-chloro-3-
(chloromethyl)benzene according to general procedure A. The residue
was purified by flash chromatography to give 510 mg (63%) of product.
1H NMR (CDCl3, 400 MHz) d: 5.40 (s, 2H), 6.64 (d, 1H, J = 2.4 Hz), 6.75 (d,
1H, J = 8.8 Hz), 6.88 (d, 1H, J = 8.0 Hz), 6.97 (t, 1H, J = 8.0 Hz), 7.21–7.31
(m, 1H), 7.35 (d, 1H, J = 2.4 Hz), 7.64 (d, 1H, J = 8.0 Hz), 7.74 (d, 1H,
J = 8.0 Hz), 7.82 (s, 1H), 10.01 (s, 1H); MS (ESI, m/z): 292.0 [M+Na]+.
5.1.4. General procedure B for the synthesis of 3–42
A solution of 50% KOH (2 mL, aq) was added dropwise to a stir-
red solution of 2 (1 mmol, 1 equiv) and indole-aldehyde (1 mmol,
1 equiv) in methanol (10 mL) at 0 °C. The resulting mixture was
stirred at room temperature for 48 h under N2 atmosphere. After
the end of reaction, the mixture was poured into ice water and
pH was brought back to 7.0 by the careful addition of 1 N HCl solu-
tion. The aqueous layer was extracted with ethyl acetate, washed
with brine, dried (Na2SO4), and then concentrated in vacuo. The
residue was purified by silica gel column chromatography to pro-
vide 3–42 as a yellow solid.
5.1.3.31. 1-(3-Bromobenzyl)-1H-indole-6-carbaldehyde (37a). The
compound 37a was prepared from indole-6-aldehyde and 1-bromo-
3-(bromomethyl)benzene according to general procedure A. The res-
idue was purified by flash chromatography to give 565 mg (60%) of
product. 1H NMR (CDCl3, 400 MHz) d: 5.35 (s, 2H), 6.64 (d, 1H,
J = 2.4 Hz), 6.98 (d, 1H, J = 8.0 Hz), 7.16 (t, 1H, J = 8.0 Hz), 7.25–7.26
(m, 1H), 7.33 (d, 1H, J = 2.4 Hz), 7.40 (d, 1H, J = 7.2 Hz), 7.63 (d, 1H,
J = 8.0 Hz), 7.73 (d, 1H, J = 8.0 Hz), 7.81 (s, 1H), 10.00 (s, 1H); MS
(ESI, m/z): 337.0 [M+Na]+.
5.1.4.1. (E)-3-(1H-Indol-4-yl)-1-(5-methoxy-2,2-dimethyl-2H-chro-
men-8-yl)prop-2-en-1-one (3). The reaction was carried out fol-
lowing the general procedure B with 1H-indole-4-carbaldehyde
(145 mg, 1 mmol) to give 3 as a yellow solid (158 mg, 44%). 1H NMR
(400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.62 (d, 1H, J = 10.0 Hz),
6.52 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H, J = 10.0 Hz), 6.95 (s, 1H), 7.22 (t,
1H, J = 8.0 Hz), 7.32 (t, 1H, J = 2.8 Hz), 7.43 (d, 1H, J = 8.0 Hz), 7.46 (d,
1H, J = 8.0 Hz), 7.75 (d, 1H, J = 8.8 Hz), 7.91 (d, 1H, J = 15.6 Hz), 8.13
(d, 1H, J = 15.6 Hz), 8.43 (s, 1H); 13C NMR (CDCl3, 100 MHz) d: 28.0,
28.0, 55.8, 77.0, 101.7, 103.5, 110.5, 113.1, 116.8, 120.5, 122.0, 122.0,
125.5, 127.3, 127.3, 127.7, 128.9, 131.8, 136.4, 140.8, 153.7, 158.4,
190.5; HRMS (ESI) calcd for [M+H]+ C23H22NO3: 360.1600, found:
360.1605.
5.1.3.32. 1-Methyl-1H-indole-7-carbaldehyde (38a). The com-
pound 38a was prepared from indole-7-aldehyde and iodometh-
ane according to general procedure A. The residue was purified
by flash chromatography to give 401 mg (84%) of product. 1H
NMR (CDCl3, 400 MHz) d: 4.13 (s, 3H), 6.58 (d, 1H, J = 2.4 Hz),
7.07 (d, 1H, J = 2.4 Hz), 7.22 (t, 1H, J = 8.0 Hz), 7.68 (d, 1H,
J = 8.0 Hz), 7.86 (d, 1H, J = 8.0 Hz), 10.21 (s, 1H); MS (ESI, m/z):
182.2 [M+Na]+.
5.1.4.2.
(E)-3-(1H-Indol-5-yl)-1-(5-methoxy-2,2-dimethyl-2H-
chromen-8-yl)prop-2-en-1-one (4). The reaction was carried
out following the general procedure B with 1H-indole-5-carbalde-
hyde (145 mg, 1 mmol) to give 4 as a yellow solid (209 mg, 58%).
1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.89 (s, 3H), 5.64 (d,
J = 10.0 Hz, 1H), 6.52 (d, J = 8.8 Hz, 1H), 6.60 (s, 1H), 6.71 (d,
J = 10.0 Hz, 1H), 7.25–7.22 (m, 1H), 7.40 (d, J = 8.5 Hz, 1H), 7.52
(dd, J = 8.5, 1.2 Hz, 1H), 7.71 (dd, J = 12.2, 10.1 Hz, 2H), 7.86 (d,
J = 15.2 Hz, 2H), 8.32 (s, 1H); 13C NMR (CDCl3, 100 MHz) d: 28.0,
28.0, 55.8, 76.8, 103.4, 103.5, 110.5, 111.6, 116.8, 121.7, 122.1,
122.8, 124.8, 125.2, 127.7, 128.3, 128.7, 131.6, 136.9, 143.8,
153.5, 158.2, 190.5; HRMS (ESI) calcd for [M+H]+ C23H22NO3:
360.1600, found: 360.1605.
5.1.3.33. 1-Ethyl-1H-indole-7-carbaldehyde (39a). The com-
pound 39a was prepared from indole-7-aldehyde and iodoethane
according to general procedure A. The residue was purified by
flash chromatography to give 395 mg (76%) of product. 1H NMR
(CDCl3, 400 MHz) d: 1.37 (t, 3H, J = 7.2 Hz), 4.64 (q, 2H,
J = 7.2 Hz), 6.60 (d, 1H, J = 2.4 Hz), 7.10 (d, 1H, J = 2.4 Hz), 7.23
(t, 1H, J = 8.0 Hz), 7.68 (d, 1H, J = 8.0 Hz), 7.88 (d, 1H, J = 8.0 Hz),
10.14 (s, 1H); MS (ESI, m/z): 196.1 [M+Na]+.
5.1.3.34. 1-(3-Fluorobenzyl)-1H-indole-7-carbaldehyde (40a). The
compound 40a was prepared from indole-7-aldehyde and 1-(bromo-
methyl)-3-fluorobenzene according to general procedure A. The resi-
due was purified by flash chromatography to give 509 mg (67%) of
product. 1H NMR (CDCl3, 400 MHz) d: 5.92 (s, 2H), 6.70 (d, 1H,
J = 2.4 Hz), 6.94–7.00 (m, 2H), 7.07–7.19 (m, 2H), 7.28–7.33 (m,
2H), 7.64 (d, 1H, J = 8.0 Hz), 7.92 (d, 1H, J = 8.0 Hz), 9.94 (s, 1H); MS
(ESI, m/z): 276.0 [M+Na]+.
5.1.4.3.
(E)-3-(1H-Indol-6-yl)-1-(5-methoxy-2,2-dimethyl-2H-
chromen-8-yl)prop-2-en-1-one (5). The reaction was carried
out following the general procedure B with 1H-indole-6-carbalde-
hyde (145 mg, 1 mmol) to give 5 as a yellow solid (243 mg, 68%).
1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.89 (s, 3H), 5.63 (d,
1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.57 (s, 1H), 6.69 (d, 1H,
J = 10.0 Hz), 7.29 (s, 1H), 7.46 (d, 1H, J = 8.8 Hz), 7.61 (s, 1H), 7.63
(d, 1H, J = 8.8 Hz), 7.71–7.75 (m, 2H), 7.83 (d, 1H, J = 15.6 Hz),
8.42 (s, 1H); 13C NMR (CDCl3, 100 MHz) d: 28.1, 28.1, 55.8, 76.9,
103.1, 103.4, 110.5, 113.2, 116.8, 119.0, 121.1, 122.0, 125.3,
126.4, 128.8, 129.6, 131.6, 136.0, 143.6, 153.6, 158.3, 190.4; HRMS
(ESI) calcd for [M+H]+ C23H22NO3: 360.1600, found: 360.1600.
5.1.3.35. 1-(3-Chlorobenzyl)-1H-indole-7-carbaldehyde (41a). The
compound 41a was prepared from indole-7-aldehyde and 1-chloro-
3-(chloromethyl)benzene according to general procedure A. The resi-
due was purified by flash chromatography to give 550 mg (68%) of
product. 1H NMR (CDCl3, 400 MHz) d: 5.91 (s, 2H), 6.70 (d, 1H,
J = 2.4 Hz), 6.92–6.93 (m, 2H), 7.13–7.16 (m, 3H), 7.19–7.20 (m,
1H), 7.65 (d, 1H, J = 8.0 Hz), 7.92 (d, 1H, J = 8.0 Hz), 9.95 (s, 1H); MS
(ESI, m/z): 292.0 [M+Na]+.
5.1.4.4.
(E)-3-(1H-Indol-7-yl)-1-(5-methoxy-2,2-dimethyl-2H-
chromen-8-yl)prop-2-en-1-one (6). The reaction was carried
out following the general procedure B with 1H-indole-7-carbalde-
hyde (145 mg, 1 mmol) to give 6 as a yellow solid (215 mg, 60%).
1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.90 (s, 3H), 5.65 (d,
1H, J = 10.0 Hz), 6.54 (d, 1H, J = 8.8 Hz), 6.61 (t, 1H, J = 2.8 Hz),
6.71 (d, 1H, J = 10.0 Hz), 7.17 (t, 1H, J = 8.0 Hz), 7.25–7.26 (m,
1H), 7.51 (d, 1H, J = 8.0 Hz), 7.69 (d, 1H, J = 8.0 Hz), 7.77 (d, 1H,
J = 8.8 Hz), 7.83 (d, 1H, J = 15.6 Hz), 8.14 (d, 1H, J = 15.6 Hz), 8.94
(s, 1H); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 55.9, 77.2, 102.9,
103.6, 110.6, 116.8, 119.5, 120.0, 121.2, 121.9, 123.0, 125.0,
126.8, 128.9, 128.9, 131.8, 135.2, 138.1, 153.8, 158.6, 190.3; HRMS
(ESI) calcd for [M+H]+ C23H22NO3: 360.1600, found: 360.1658.
5.1.3.36.
(42a).
1-(3-Bromobenzyl)-1H-indole-7-carbaldehyde
The compound 42a was prepared from indole-7-alde-
hyde and 1-bromo-3-(bromomethyl)benzene according to general
procedure A. The residue was purified by flash chromatography to
give 660 mg (70%) of product. 1H NMR (CDCl3, 400 MHz) d: 5.81 (s,
2H), 6.61 (d, 1H, J = 2.4 Hz), 6.73 (d, 1H, J = 8.0 Hz), 6.97 (d, 1H,
J = 8.0 Hz), 7.00–7.03 (m, 1H), 7.09 (d, 1H, J = 2.4 Hz), 7.18 (d, 1H,
J = 8.0 Hz), 7.22 (d, 1H, J = 8.0 Hz), 7.56 (d, 1H, J = 8.0 Hz), 7.83 (d,
1H, J = 8.0 Hz), 9.85 (s, 1H); MS (ESI, m/z): 337.0 [M+Na]+.

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2071
5.1.4.5. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
(methoxymethyl)-1H-indol-3-yl)prop-2-en-1-one (7). The
J = 6.8 Hz), 5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.0 Hz), 6.71
(d, 1H, J = 10.0 Hz), 7.22 (d, 1H, J = 8.0 Hz), 7.29 (t, 1H, J = 8.0 Hz),
7.36 (d, 1H, J = 8.0 Hz), 7.46 (s, 1H), 7.75–7.78 (m, 2H), 7.99 (d,
1H, J = 15.6 Hz), 8.06 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3,
100 MHz) d: 18.1, 25.7, 27.9, 27.9, 44.4, 55.8, 76.9, 103.3, 110.3,
110.5, 113.4, 116.9, 118.7, 121.1, 122.3, 122.8, 126.5, 128.8,
131.8, 133.0, 136.4, 137.6, 138.0, 153.4, 158.0, 190.1; HRMS (ESI)
calcd for [M+H]+ C28H30NO3: 428.2226, found: 428.2221.
reaction was carried out following the general procedure B with
7a (189 mg, 1 mmol) to give 7 as a yellow solid (149 mg, 37%).
1H NMR (CDCl3, 400 MHz) d: 1.53 (s, 6H), 3.28 (s, 3H), 3.89 (s,
3H), 5.47 (s, 2H), 5.64 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz),
6.71 (d, 1H, J = 10.0 Hz), 7.28 (d, 1H, J = 8.0 Hz), 7.34 (t, 1H,
J = 8.0 Hz), 7.51 (s, 1H), 7.52 (d, 1H, J = 8.0 Hz), 7.60 (d, 1H,
J = 8.0 Hz), 7.81 (d, 1H, J = 16.0 Hz), 7.97 (d, 1H, J = 16.0 Hz), 8.08
(d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 55.8,
56.2, 77.0, 77.8, 103.4, 110.5, 110.8, 114.6, 116.9, 121.2, 121.7,
122.2, 123.5, 123.8, 126.7, 128.8, 131.8, 133.2, 135.4, 137.6,
153.5, 158.1, 190.1; HRMS (ESI) calcd for [M+H]+ C25H26NO4:
404.1862, found: 404.1858.
5.1.4.10. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
(2-morpholinoethyl)-1H-indol-3-yl)prop-2-en-1-one (12). The
reaction was carried out following the general procedure B with
12a (189 mg, 1 mmol) to give 12 as a yellow solid (111 mg, 26%).
1H NMR (400 MHz, CDCl3) d: 1.53 (s, 6H), 2.49 (t, 4H, J = 4.4 Hz),
2.77 (t, 2H, J = 6.4 Hz), 3.70 (t, 4H, J = 4.4 Hz), 3.89 (s, 3H), 4.25 (t,
2H, J = 6.4 Hz), 5.64 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz),
6.71 (d, 1H, J = 10.0 Hz), 7.22 (d, 1H, J = 8.0 Hz), 7.30 (t, 1H,
J = 8.0 Hz), 7.38 (d, 1H, J = 8.0 Hz), 7.52 (s, 1H), 7.75 (d, 1H,
J = 8.8 Hz), 7.76 (d, 1H, J = 15.6 Hz), 7.98 (d, 1H, J = 15.6 Hz), 8.07
(d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 44.1,
53.8, 53.8, 55.8, 55.8, 57.8, 66.9, 76.9, 103.4, 110.0, 110.5, 113.6,
116.9, 121.1, 121.3, 122.4, 122.7, 122.9, 126.2, 128.8, 131.8, 133.9,
136.0, 137.5, 153.4, 158.0, 190.1; HRMS (ESI) calcd for [M+H]+
C29H33N2O4: 473.2440, found: 473.2445.
5.1.4.6. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
methyl-1H-indol-3-yl)prop-2-en-1-one (8). The reaction was
carried out following the general procedure B with 8a (189 mg,
1 mmol) to give 8 as a yellow solid (153 mg, 41%). 1H NMR
(400 MHz, CDCl3) d: 1.52 (s, 6H), 3.83 (s, 3H), 3.89 (s, 3H), 5.63
(d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.71 (d, 1H,
J = 10.0 Hz), 7.23 (d, 1H, J = 7.2 Hz), 7.30–7.37 (m, 2H), 7.39 (s,
1H), 7.74 (d, 1H, J = 8.8 Hz), 7.75 (d, 1H, J = 16.0 Hz), 7.97 (d, 1H,
J = 16.0 Hz), 8.07 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d:
28.0, 28.0, 33.2, 55.8, 76.9, 103.3, 110.0, 110.5, 113.5, 116.9,
121.1, 121.1, 122.4, 122.7, 122.9, 126.2, 128.8, 131.7, 134.2,
135.9, 138.2, 153.4, 158.0, 190.2; HRMS (ESI) calcd for [M+H]+
C24H24NO3: 374.1756, found: 374.1752.
5.1.4.11.
(E)-3-(1-Benzyl-1H-indol-3-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (13). The reac-
tion was carried out following the general procedure B with 13a
(189 mg, 1 mmol) to give 13 as a yellow solid (189 mg, 42%). 1H
NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.88 (s, 3H), 5.32 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H,
J = 10.0 Hz), 7.15–7.16 (m, 2H), 7.22–7.25 (m, 2H), 7.27–7.32 (m,
4H), 7.44 (s, 1H), 7.74 (d, 1H, J = 8.8 Hz), 7.97 (d, 1H, J = 16.0 Hz),
8.08 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0,
50.5, 55.8, 76.9, 103.4, 110.5, 110.5, 114.0, 116.9, 121.2, 121.3,
122.3, 123.0, 123.1, 126.4, 127.0, 127.0, 128.1, 128.8, 129.0,
129.0, 131.8, 133.5, 135.9, 136.2, 137.8, 153.4, 158.0, 190.1; HRMS
(ESI) calcd for [M+H]+ C30H28NO3: 450.2069, found: 450.2061.
5.1.4.7.
(E)-3-(1-Ethyl-1H-indol-3-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (9). The reaction
was carried out following the general procedure B with 9a
(189 mg, 1 mmol) to give 9 as a yellow solid (154 mg, 40%). 1H
NMR (400 MHz, CDCl3) d: 1.21 (t, 3H, J = 7.2 Hz), 1.52 (s, 6H),
3.45 (q, 2H, J = 7.2 Hz), 3.88 (s, 3H), 3.63 (d, 1H, J = 10.0 Hz), 6.51
(d, 1H, J = 8.8 Hz), 6.71 (d, 1H, J = 10.0 Hz), 7.22 (d, 1H, J = 8.0 Hz),
7.30 (t, 1H, J = 8.0 Hz), 7.37 (d, 1H, J = 8.0 Hz), 7.45 (s, 1H), 7.75
(d, 1H, J = 8.8 Hz), 7.76 (d, 1H, J = 15.6 Hz), 7.98 (d, 1H,
J = 15.6 Hz), 8.07 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d:
15.2, 28.0, 28.0, 41.4, 55.8, 76.9, 103.3, 110.1, 110.5, 113.5, 116.9,
121.0, 121.2, 122.4, 122.6, 122.8, 126.3, 128.8, 131.7, 132.6,
136.1, 137.3, 153.4, 158.0, 190.2; HRMS (ESI) calcd for [M+H]+
C25H26NO3: 388.1913, found: 388.1907.
5.1.4.12. (E)-3-(1-(2-Fluorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(14). The
reaction was carried out following the general procedure B with
14a (189 mg, 1 mmol) to give 14 as a yellow solid (215 mg, 46%).
1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.88 (s, 3H), 5.37 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H,
J = 10.0 Hz), 6.98 (t, 1H, J = 7.2 Hz), 7.05 (t, 1H, J = 7.2 Hz), 7.10 (t,
1H, J = 8.8 Hz), 7.23–7.30 (m, 3H), 7.37 (d, 1H, J = 7.2 Hz), 7.50 (s,
1H), 7.75 (d, 1H, J = 8.8 Hz), 7.77 (d, 1H, J = 16.0 Hz), 7.98 (d, 1H,
J = 16.0 Hz), 8.07 (d, 1H, J = 7.2 Hz); 13C NMR (CDCl3, 100 MHz) d:
28.0, 28.0, 44.2, 55.8, 76.9, 103.4, 110.3, 110.5, 114.2, 115.6, 115.8,
116.9, 121.2, 121.3, 122.2, 123.1, 123.2, 124.7, 126.4, 128.8, 129.2,
130.0, 130.1, 131.8, 133.4, 135.8, 137.6, 153.5, 158.1, 190.0; HRMS
(ESI) calcd for [M+H]+ C30H27FNO3: 468.1975, found: 468.1976.
5.1.4.8.
(E)-3-(1-Isopropyl-1H-indol-3-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (10). The reac-
tion was carried out following the general procedure B with 10a
(189 mg, 1 mmol) to give 10 as a yellow solid (132 mg, 33%). 1H
NMR (400 MHz, CDCl3) d: 1.63 (s, 6H), 1.55 (d, 6H, J = 6.8 Hz),
3.88 (s, 3H), 4.67 (heptet, 1H, J = 6.8 Hz), 5.63 (d, 1H, J = 10.0 Hz),
6.51 (d, 1H, J = 8.8 Hz), 6.71 (d, 1H, J = 10.0 Hz), 7.22 (d, 1H,
J = 8.0 Hz), 7.29 (t, 1H, J = 8.0 Hz), 7.55 (s, 1H), 7.75 (d, 1H,
J = 8.8 Hz), 7.76 (d, 1H, J = 15.6 Hz), 7.99 (d, 1H, J = 15.6 Hz), 8.07
(d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 22.7, 22.7, 27.9,
27.9, 47.5, 55.8, 76.9, 103.3, 110.2, 110.5, 113.7, 116.9, 121.1,
121.2, 122.5, 122.5, 122.7, 126.3, 128.8, 129.5, 131.7, 136.2,
137.2, 153.4, 157.9, 190.1; HRMS (ESI) calcd for [M+H]+
C26H28NO3: 402.2069, found: 402.2066.
5.1.4.13. (E)-3-(1-(3-Fluorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one (15). The reac-
tion was carried out following the general procedure B with 15a
(189 mg, 1 mmol) to give 15 as a yellow solid (187 mg, 40%). 1H
NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.88 (s, 3H), 5.32 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.71 (d, 1H,
J = 10.0 Hz), 6.82 (d, 1H, J = 8.0 Hz), 6.91 (d, 1H, J = 8.0 Hz), 6.96 (t,
1H, J = 8.0 Hz), 7.27–7.31 (m, 4H), 7.45 (s, 1H), 7.75 (d, 1H,
J = 8.8 Hz), 7.79 (d, 1H, J = 15.6 Hz), 7.98 (d, 1H, J = 15.6 Hz), 8.09 (d,
1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.9, 55.8,
76.9, 103.4, 110.4, 110.5, 113.8, 114.0, 114.2, 114.9, 115.1, 116.9,
5.1.4.9. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
(3-methylbut-2-en-1-yl)-1H-indol-3-yl)prop-2-en-1-one
(11). The reaction was carried out following the general proce-
dure B with 11a (189 mg, 1 mmol) to give 11 as a yellow solid
(167 mg, 39%). 1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 1.80 (s,
3H), 1.83 (s, 3H), 3.89 (s, 3H), 4.69 (d, 2H, J = 6.8 Hz), 5.40 (t, 1H,

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
121.3, 121.4, 122.3, 122.4, 123.3, 126.4, 128.8, 130.6, 131.8, 133.3,
135.5, 137.6, 138.8, 153.4, 158.1, 190.1; HRMS (ESI) calcd for
[M+H]+ C30H27FNO3: 468.1975, found: 468.1978.
5.1.4.18. (E)-3-(1-(2-Bromobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one (20). The
reaction was carried out following the general procedure B with
20a (189 mg, 1 mmol) to give 20 as a yellow solid (180 mg, 34%).
1H NMR (400 MHz, CDCl3) d: 1.53 (s, 6H), 3.88 (s, 3H), 5.40 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.68 (d, 1H,
J = 4.8 Hz), 6.71 (d, 1H, J = 10.0 Hz), 7.22–7.31 (m, 5H), 7.45 (s, 1H),
7.62 (t, 1H, J = 4.8 Hz), 7.75 (d, 1H, J = 8.8 Hz), 7.79 (d, 1H,
J = 15.6 Hz), 7.98 (d, 1H, J = 15.6 Hz), 8.10 (d, 1H, J = 8.0 Hz); 13C
NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 50.5, 55.8, 76.9, 103.4, 110.5,
110.5, 114.3, 116.9, 121.2, 121.4, 122.2, 122.6, 123.2, 123.3, 126.3,
128.0, 128.3, 128.8, 129.6, 131.8, 133.0, 133.5, 135.5, 135.6, 137.7,
153.5, 158.1, 190.0; HRMS (ESI) calcd for [M+H]+ C30H27BrNO3:
528.1174, found: 528.1171.
5.1.4.14. (E)-3-(1-(4-Fluorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(16). The
reaction was carried out following the general procedure B with
16a (189 mg, 1 mmol) to give 16 as a yellow solid (145 mg,
31%). 1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.30
(s, 2H), 5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.71 (d,
1H, J = 10.0 Hz), 7.01 (d, 2H, J = 8.0 Hz), 7.14 (d, 2H, J = 8.0 Hz),
7.23–7.30 (m, 5H), 7.43 (s, 1H), 7.75–7.81 (m, 2H), 7.96 (d, 1H,
J = 15.6 Hz), 8.08 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d:
27.9, 27.9, 49.8, 55.8, 76.9, 103.4, 110.4, 110.5, 114.1, 115.8,
116.0, 116.9, 121.2, 121.3, 122.2, 123.1, 123.2, 126.5, 128.7,
128.8, 128.8, 131.8, 132.0, 132.0, 133.3, 135.7, 137.6, 153.4,
158.1, 190.0; HRMS (ESI) calcd for [M+H]+ C30H27FNO3: 468.1975,
found: 468.1977.
5.1.4.19. (E)-3-(1-(3-Bromobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(21). The
reaction was carried out following the general procedure B with
21a (189 mg, 1 mmol) to give 21 as a yellow solid (248 mg, 47%).
1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.88 (s, 3H), 5.29 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H,
J = 10.0 Hz), 7.02 (d, 1H, J = 8.0 Hz), 7.17 (t, 1H, J = 8.0 Hz),
7.23–7.29 (m, 3H), 7.34 (s, 1H), 7.41–7.44 (m, 2H), 7.75 (d, 1H,
J = 8.8 Hz), 7.78 (d, 1H, J = 15.6 Hz), 7.97 (d, 1H, J = 15.6 Hz), 8.08
(d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.8,
55.8, 76.9, 103.4, 110.4, 110.5, 114.3, 116.9, 121.3, 121.4, 122.2,
123.1, 123.3, 123.3, 125.5, 126.4, 128.8, 129.9, 130.6, 131.3, 131.8,
133.3, 135.6, 137.6, 138.6, 153.5, 158.1, 190.0; HRMS (ESI) calcd
for [M+H]+ C30H27BrNO3: 528.1174, found: 528.1178.
5.1.4.15. (E)-3-(1-(2-Chlorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(17). The
reaction was carried out following the general procedure B with
17a (189 mg, 1 mmol) to give 17 as a yellow solid (189 mg,
39%). 1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.88 (s, 3H), 5.43
(s, 2H), 5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.0 Hz), 6.71 (d,
1H, J = 10.0 Hz), 6.75 (d, 1H, J = 8.0 Hz), 7.13 (t, 1H, J = 8.0 Hz),
7.22–7.30 (m, 4H), 7.42 (d, 1H, J = 8.0 Hz), 7.44 (d, 1H, J = 8.0 Hz),
7.75 (d, 1H, J = 8.0 Hz), 7.79 (d, 1H, J = 16.0 Hz), 7.98 (d, 1H,
J = 16.0 Hz), 8.10 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d:
28.0, 28.0, 48.0, 55.8, 76.9, 103.4, 110.4, 110.5, 114.2, 116.9,
121.2, 121.4, 122.3, 123.2, 123.3, 126.4, 127.4, 128.3, 128.8,
129.3, 129.8, 131.8, 132.7, 133.5, 133.9, 135.6, 137.7, 153.4,
158.1, 190.1; HRMS (ESI) calcd for [M+H]+ C30H27ClNO3:
484.1679, found: 484.1674.
5.1.4.20. (E)-3-(1-(4-Bromobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(22). The
reaction was carried out following the general procedure B with
22a (189 mg, 1 mmol) to give 22 as a yellow solid (190 mg, 36%).
1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.88 (s, 3H), 5.28 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.51 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H,
J = 10.0 Hz), 7.00 (d, 2H, J = 8.0 Hz), 7.22–7.29 (m, 3H), 7.43–7.45
(m, 3H), 7.74 (d, 1H, J = 8.8 Hz), 7.78 (d, 1H, J = 16.0 Hz), 7.96 (d,
1H, J = 16.0 Hz), 8.08 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz)
d: 27.9, 27.9, 49.9, 55.8, 76.9, 103.4, 110.4, 110.5, 114.2, 116.9,
121.3, 121.4, 122.0, 122.2, 123.2, 123.2, 126.4, 128.6, 128.6, 128.8,
131.8, 132.1, 132.1, 133.3, 135.3, 135.6, 137.6, 153.4, 158.1, 190.1;
HRMS (ESI) calcd for [M+H]+ C30H27BrNO3: 528.1174, found:
528.1170.
5.1.4.16. (E)-3-(1-(3-Chlorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(18). The
reaction was carried out following the general procedure B with
18a (189 mg, 1 mmol) to give 18 as a yellow solid (218 mg,
45%). 1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.89 (s, 3H), 5.31
(s, 2H), 5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.71 (d,
1H, J = 10.0 Hz), 6.99 (d, 1H, J = 8.0 Hz), 7.11 (s, 1H), 7.23–7.31
(m, 5H), 7.45 (s, 1H), 7.75 (d, 1H, J = 8.8 Hz), 7.79 (d, 1H,
J = 16.0 Hz), 7.97 (d, 1H, J = 16.0 Hz), 8.09 (d, 1H, J = 8.0 Hz); 13C
NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.9, 55.8, 76.9, 103.4,
110.4, 110.5, 114.3, 116.9, 121.3, 121.4, 122.2, 123.3, 123.3,
125.0, 126.4, 127.0, 128.3, 128.8, 130.3, 131.8, 133.3, 134.9,
135.6, 137.6, 138.3, 153.5, 158.1, 190.0; HRMS (ESI) calcd for
[M+H]+ C30H27ClNO3: 484.1679, found: 484.1679.
5.1.4.21. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-(2-(trifluoromethyl)benzyl)-1H-indol-3-yl)prop-2-en-1-one
(23). The reaction was carried out following the general proce-
dure B with 23a (189 mg, 1 mmol) to give 23 as a yellow solid
(150 mg, 29%). 1H NMR (400 MHz, CDCl3) d: 1.53 (s, 6H), 3.89 (s,
3H), 5.57 (s, 2H), 5.64 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz),
6.68 (d, 1H, J = 4.8 Hz), 6.71 (d, 1H, J = 10.0 Hz), 7.20–7.31 (m,
3H), 7.34–7.40 (m, 2H), 7.47 (s, 1H), 7.73 (d, 1H, J = 4.8 Hz), 7.76
(d, 1H, J = 8.8 Hz), 7.81 (d, 1H, J = 15.6 Hz), 7.99 (d, 1H,
J = 15.6 Hz), 8.11 (d, 1H, J = 8.8 Hz); 13C NMR (CDCl3, 100 MHz) d:
28.0, 28.0, 46.8, 55.8, 76.9, 103.4, 110.4, 110.5, 114.5, 116.9,
121.3, 121.5, 122.2, 123.4, 123.4, 126.2, 126.2, 126.4, 127.1,
127.5, 127.9, 128.8, 131.8, 132.6, 133.6, 135.1, 135.5, 137.7,
153.5, 158.1, 190.0; HRMS (ESI) calcd for [M+H]+ C31H27F3NO3:
518.1943, found: 518.1943.
5.1.4.17. (E)-3-(1-(4-Chlorobenzyl)-1H-indol-3-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(19). The
reaction was carried out following the general procedure B with
19a (189 mg, 1 mmol) to give 19 as a yellow solid (203 mg, 42%).
1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.30 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.71 (d, 1H,
J = 10.0 Hz), 7.07 (d, 1H, J = 8.0 Hz), 7.22–7.27 (m, 5H), 7.28 (d, 1H,
J = 8.0 Hz), 7.44 (s, 1H), 7.75 (d, 1H, J = 8.8 Hz), 7.78 (d, 1H,
J = 15.6 Hz), 7.96 (d, 1H, J = 15.6 Hz), 8.08 (d, 1H, J = 8.0 Hz); 13C
NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.9, 55.8, 76.9, 103.4, 110.4,
110.5, 114.2, 116.9, 121.3, 121.4, 122.2, 123.2, 123.2, 126.5, 128.3,
128.3, 128.8, 129.2, 129.2, 131.8, 133.3, 133.9, 134.7, 135.6, 137.6,
153.5, 158.1, 190.0; HRMS (ESI) calcd for [M+H]+ C30H27ClNO3:
484.1679, found: 484.1674.
5.1.4.22. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-(3-(trifluoromethyl)benzyl)-1H-indol-3-yl)prop-2-en-1-one
(24). The reaction was carried out following the general proce-
dure B with 24a (189 mg, 1 mmol) to give 24 as a yellow solid
(181 mg, 35%). 1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.88 (s,

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2073
3H), 5.39 (s, 2H), 5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz),
6.71 (d, 1H, J = 10.0 Hz), 7.23–7.27 (m, 5H), 7.41 (d, 1H,
J = 8.0 Hz), 7.45 (d, 1H, J = 8.0 Hz), 7.50 (s, 1H), 7.76 (d, 1H,
J = 8.8 Hz), 7.79 (d, 1H, J = 15.6 Hz), 7.99 (d, 1H, J = 15.6 Hz), 8.09
(d, 1H, J = 8.0 Hz); 13C NMR (CDCl3, 100 MHz) d: 27.9, 27.9, 50.0,
55.8, 76.9, 103.4, 110.3, 110.5, 114.4, 116.9, 121.3, 121.5, 122.2,
123.4, 123.4, 123.7, 123.7, 125.0, 125.0, 126.5, 128.8, 129.7,
130.2, 131.8, 133.1, 135.5, 137.4, 137.6, 153.5, 158.1, 190.0; HRMS
(ESI) calcd for [M+H]+ C31H27F3NO3: 518.1943, found: 518.1948.
131.8, 136.7, 139.8, 140.2, 153.7, 158.4, 190.2; HRMS (ESI) calcd
for [M+H]+ C30H27FNO3: 468.1975, found: 468.1971.
5.1.4.27. (E)-3-(1-(3-Chlorobenzyl)-1H-indol-4-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(29). The
reaction was carried out following the general procedure B with
29a (189 mg, 1 mmol) to give 29 as a yellow solid (213 mg, 44%).
1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.33 (s, 2H),
5.63 (d, 1H, J = 10.0 Hz), 6.53 (d, 1H, J = 8.8 Hz), 6.70 (d, 1H,
J = 10.0 Hz), 6.94–6.96 (m, 2H), 7.13 (s, 1H), 7.21–7.29 (m, 5H),
7.47 (d, 1H, J = 8.0 Hz), 7.75 (d, 1H, J = 8.8 Hz), 7.91 (d, 1H,
J = 15.6 Hz), 8.13 (d, 1H, J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d:
28.0, 28.0, 49.7, 55.8, 77.0, 101.2, 103.5, 110.5, 111.4, 116.8, 120.2,
122.0, 122.0, 124.8, 126.8, 127.5, 128.0, 128.2, 128.3, 128.8, 129.3,
130.2, 131.8, 134.8, 136.7, 139.3, 140.2, 153.7, 158.4, 190.2; HRMS
(ESI) calcd for [M+H]+ C30H27ClNO3: 484.1679, found: 484.1679.
5.1.4.23. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-
3-(1-(4-(trifluoromethyl)benzyl)-1H-indol-3-yl)prop-2-en-1-
one (25). The reaction was carried out following the general
procedure B with 25a (189 mg, 1 mmol) to give 25 as a yellow solid
(166 mg, 32%). 1H NMR (400 MHz, CDCl3) d: 1.52 (s, 6H), 3.89 (s,
3H), 5.40 (s, 2H), 5.63 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz),
6.71 (d, 1H, J = 10.0 Hz), 7.21–7.29 (m, 5H), 7.46 (s, 1H), 7.57 (d,
2H, J = 8.0 Hz), 7.75 (d, 1H, J = 8.8 Hz), 7.80 (d, 1H, J = 15.6 Hz),
7.97 (d, 1H, J = 15.6 Hz), 8.10 (d, 1H, J = 8.0 Hz); 13C NMR (CDCl3,
100 MHz) d: 27.9, 27.9, 50.0, 55.8, 76.9, 103.4, 110.3, 110.5,
114.4, 116.9, 121.3, 121.5, 122.2, 123.4, 123.4, 125.9, 126.0,
126.0, 126.0, 126.4, 127.1, 127.1, 128.8, 131.8, 133.2, 135.4,
137.6, 140.4, 153.5, 158.1, 190.0; HRMS (ESI) calcd for [M+H]+
C31H27F3NO3: 518.1943, found: 518.1942.
5.1.4.28. (E)-3-(1-(3-Bromobenzyl)-1H-indol-4-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one (30). The reac-
tion was carried out following the general procedure B with 30a
(189 mg, 1 mmol) to give 30 as a yellow solid (217 mg, 41%). 1H
NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.33 (s, 2H), 5.62
(d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.69 (d, 1H, J = 10.0 Hz),
6.95–6.99 (m, 2H), 7.14–7.30 (m, 5H), 7.39 (d, 1H, J = 8.0 Hz), 7.47
(d, 1H, J = 8.0 Hz), 7.75 (d, 1H, J = 8.8 Hz), 7.91 (d, 1H, J = 15.6 Hz),
8.13 (d, 1H, J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0,
49.7, 55.8, 77.0, 101.2, 103.5, 110.5, 111.4, 116.8, 120.2, 122.0,
122.1, 123.0, 125.3, 127.6, 128.2, 128.3, 128.8, 129.3, 129.7, 130.5,
130.9, 131.8, 136.7, 139.6, 140.2, 153.7, 158.4, 190.2; HRMS (ESI)
calcd for [M+H]+ C30H27BrNO3: 528.1174, found: 528.1179.
5.1.4.24. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-4-yl)prop-2-en-1-one (26). The reaction
was carried out following the general procedure B with 26a
(189 mg, 1 mmol) to give 26 as a yellow solid (175 mg, 47%). 1H
NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.83 (s, 3H), 3.89 (s, 3H),
5.62 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.69 (d, 1H,
J = 10.0 Hz), 6.87 (d, 1H, J = 2.8 Hz), 7.15 (d, 1H, J = 2.8 Hz),
7.23–7.27 (m, 2H), 7.36 (d, 1H, J = 8.0 Hz), 7.45 (d, 1H, J = 8.0 Hz),
7.74 (d, 1H, J = 8.8 Hz), 7.89 (d, 1H, J = 15.6 Hz), 8.11 (d, 1H,
J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 33.1, 55.8,
77.0, 100.2, 103.5, 110.5, 111.1, 116.8, 120.2, 121.6, 122.0, 127.4,
127.9, 128.8, 130.0, 131.8, 137.2, 140.6, 153.7, 158.3, 190.3; HRMS
(ESI) calcd for [M+H]+ C24H24NO3: 374.1756, found: 374.1754.
5.1.4.29. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-5-yl)prop-2-en-1-one (31). The reaction
was carried out following the general procedure B with 31a
(189 mg, 1 mmol) to give 31 as a yellow solid (179 mg, 48%). 1H
NMR (CDCl3, 400 MHz) d: 1.52 (s, 6H), 3.81 (s, 3H), 3.89 (s, 3H),
5.62 (d, 1H, J = 10.0 Hz), 6.51–6.53 (m, 2H), 6.69 (d, 1H,
J = 10.0 Hz), 7.07 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.54
(d, 1H, J = 8.8 Hz), 7.67–7.72 (m, 2H), 7.84–7.88 (m, 2H); 13C
NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 33.0, 55.8, 76.8, 102.0,
103.4, 109.8, 110.5, 116.8, 121.2, 122.2, 123.0, 124.6, 127.2,
128.7, 128.8, 129.9, 131.6, 137.8, 134.9, 153.5, 158.1, 190.4; HRMS
(ESI) calcd for [M+H]+ C24H24NO3: 374.1756, found: 374.1758.
5.1.4.25.
(E)-3-(1-Ethyl-1H-indol-4-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (27). The reac-
tion was carried out following the general procedure B with 27a
(189 mg, 1 mmol) to give 27 as a yellow solid (190 mg, 49%). 1H
NMR (400 MHz, CDCl3) d: 1.49 (t, 3H, J = 7.2 Hz), 1.51 (s, 6H),
3.89 (s, 3H), 4.18 (q, 2H, J = 7.2 Hz), 5.62 (d, 1H, J = 10.0 Hz), 6.52
(d, 1H, J = 8.8 Hz), 6.69 (d, 1H, J = 10.0 Hz), 6.88 (d, 1H, J = 2.8 Hz),
7.22–7.23 (m, 2H), 7.38 (d, 1H, J = 8.0 Hz), 7.45 (d, 1H, J = 8.0 Hz),
7.74 (d, 1H, J = 8.8 Hz), 7.89 (d, 1H, J = 15.6 Hz), 8.12 (d, 1H,
J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 15.5, 28.0, 28.0, 41.2,
55.8, 77.0, 100.3, 103.4, 110.5, 111.1, 116.8, 120.0, 121.4, 122.1,
127.3, 128.0, 128.1, 128.2, 128.8, 131.8, 136.2, 140.7, 153.7,
158.3, 190.3; HRMS (ESI) calcd for [M+H]+ C25H26NO3: 388.1913,
found: 388.1918.
5.1.4.30. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-(2-(piperidin-1-yl)ethyl)-1H-indol-5-yl)prop-2-en-1-one
(32). The reaction was carried out following the general proce-
dure B with 32a (189 mg, 1 mmol) to give 32 as a yellow solid
(99 mg, 21%). 1H NMR (CDCl3, 400 MHz) d: 1.47–1.41 (m, 2H),
1.52 (s, 6H), 1.59 (dt, J = 11.0, 5.6 Hz, 4H), 2.45 (s, 4H), 2.70 (t,
J = 7.2 Hz, 2H), 3.88 (s, 3H), 4.24 (t, J = 7.2 Hz, 2H), 5.63 (d,
J = 10.0 Hz, 1H), 6.51 (dd, J = 6.0, 2.7 Hz, 2H), 6.70 (d, J = 10.0 Hz,
1H), 7.16 (d, J = 3.1 Hz, 1H),7.36 (d, J = 8.6 Hz, 1H), 7.57–7.49 (m,
1H),7.70 (dd, J = 12.2, 10.4 Hz, 2H), 7.86 (d, J = 15.5 Hz, 2H); HRMS
(ESI) calcd for [M+H]+ C30H35N2O3: 471.2648, found: 471.2646.
5.1.4.26. (E)-3-(1-(3-Fluorobenzyl)-1H-indol-4-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(28). The
5.1.4.31. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-6-yl)prop-2-en-1-one (33). The reaction
was carried out following the general procedure B with 33a
(189 mg, 1 mmol) to give 33 as a yellow solid (172 mg, 46%). 1H
NMR (400 MHz, CDCl3) d: 1.53 (s, 6H), 3.81 (s, 3H), 3.88 (s, 3H),
5.63 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 2.8 Hz), 6.51 (d, 1H,
J = 8.8 Hz), 6.70 (d, 1H, J = 10.0 Hz), 7.12 (d, 1H, J = 2.8 Hz), 7.42
(d, 1H, J = 8.8 Hz), 7.54 (s, 1H), 7.60 (d, 1H, J = 8.8 Hz), 7.72–7.79
(m, 2H), 7.85 (d, 1H, J = 15.6 Hz). 13C NMR (CDCl3, 100 MHz) d:
28.1, 28.1, 32.9, 55.8, 76.8, 101.5, 103.4, 110.5, 110.8, 116.8,
reaction was carried out following the general procedure B with
28a (189 mg, 1 mmol) to give 28 as a yellow solid (164 mg,
35%). 1H NMR (400 MHz, CDCl3) d: 1.51 (s, 6H), 3.89 (s, 3H), 5.34
(s, 2H), 5.62 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.69 (d,
1H, J = 10.0 Hz), 6.77 (d, 1H, J = 8.0 Hz), 6.87 (d, 1H, J = 8.0 Hz),
6.93–6.96 (m, 2H), 7.18–7.29 (m, 4H), 7.47 (d, 1H, J = 8.0 Hz),
7.75 (d, 1H, J = 8.8 Hz), 7.91 (d, 1H, J = 15.6 Hz), 8.13 (d, 1H,
J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.8, 55.8,
77.0, 101.2, 103.5, 110.5, 111.4, 113.6, 113.8, 114.6, 114.8, 116.8,
120.2, 122.0, 122.2, 127.5, 128.2, 128.3, 128.8, 129.3, 130.5,

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
118.9, 121.2, 122.0, 125.4, 128.7, 129.3, 130.2, 130.9, 131.7, 136.9,
143.5, 153.6, 158.2, 190.2; HRMS (ESI) calcd for [M+H]+ C24H24NO3:
374.1756, found: 374.1761.
5.1.4.36. (E)-1-(5-Methoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-7-yl)prop-2-en-1-one (38). The reaction
was carried out following the general procedure B with 38a
(189 mg, 1 mmol) to give 38 as a yellow solid (168 mg, 45%). 1H
NMR (400 MHz, CDCl3) d: 1.53 (s, 6H), 3.89 (s, 3H), 4.10 (s, 3H),
5.63 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 2.8 Hz), 6.53 (d, 1H,
J = 8.8 Hz), 6.69 (d, 1H, J = 10.0 Hz), 7.00 (d, 1H, J = 2.8 Hz), 7.11 (t,
1H, J = 8.0 Hz), 7.51 (d, 1H, J = 8.0 Hz), 7.64 (d, 1H, J = 8.0 Hz), 7.71
(d, 1H, J = 15.6 Hz), 7.75 (d, 1H, J = 8.8 Hz), 8.58 (d, 1H, J = 15.6 Hz);
13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 37.9, 55.8, 77.0, 101.3,
103.6, 110.5, 116.8, 119.7, 121.1, 121.5, 121.7, 123.0, 128.4, 128.8,
130.5, 131.4, 131.8, 134.7, 138.6, 153.9, 158.5, 189.5; HRMS (ESI)
calcd for [M+H]+ C24H24NO3: 374.1756, found: 374.1752.
5.1.4.32.
(E)-3-(1-Ethyl-1H-indol-6-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (34). The reac-
tion was carried out following the general procedure B with
34a (189 mg, 1 mmol) to give 34 as a yellow solid (120 mg,
31%). 1H NMR (400 MHz, CDCl3) d: 1.49 (t, 3H, J = 7.2 Hz), 1.53
(s, 6H), 3.89 (s, 3H), 4.18 (q, 2H, J = 7.2 Hz), 5.63 (d, 1H,
J = 10.0 Hz), 6.50 (d, 1H, J = 2.8 Hz), 6.52 (d, 1H, J = 8.8 Hz), 6.70
(d, 1H, J = 10.0 Hz), 7.19 (d, 1H, J = 2.8 Hz), 7.42 (d, 1H,
J = 8.0 Hz), 7.57 (s, 1H), 7.61 (d, 1H, J = 8.0 Hz), 7.72–7.78 (m,
2H), 7.85 (d, 1H, J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 15.5,
28.0, 28.0, 41.1, 55.8, 76.8, 101.6, 103.4, 110.4, 110.8, 116.8,
118.9, 121.3, 122.1, 125.3, 128.7, 129.2, 129.2, 130.4, 131.7,
135.8, 143.6, 153.6, 158.2, 190.2; HRMS (ESI) calcd for [M+H]+
C25H26NO3: 388.1913, found: 388.1911.
5.1.4.37.
(E)-3-(1-Ethyl-1H-indol-7-yl)-1-(5-methoxy-2,2-
dimethyl-2H-chromen-8-yl)prop-2-en-1-one (39). The reac-
tion was carried out following the general procedure B with 39a
(189 mg, 1 mmol) to give 39 as a yellow solid (155 mg, 40%). 1H
NMR (400 MHz, CDCl3) d: 1.51 (t, 3H, J = 2.8 Hz), 1.52 (s, 6H),
3.89 (s, 3H), 4.38 (q, 2H, J = 2.8 Hz), 5.63 (d, 1H, J = 10.0 Hz), 6.51
(d, 1H, J = 2.8 Hz), 6.53 (d, 1H, J = 8.8 Hz), 6.69 (d, 1H, J = 10.0 Hz),
7.09–7.13 (m, 2H), 7.47 (d, 1H, J = 8.0 Hz), 7.64 (d, 1H, J = 8.0 Hz),
7.68 (d, 1H, J = 15.6 Hz), 7.75 (d, 1H, J = 8.8 Hz), 8.44 (d, 1H,
J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 16.7, 28.0, 28.0, 44.5,
55.8, 77.0, 101.7, 103.6, 110.5, 116.8, 119.6, 121.2, 121.4, 121.6,
122.9, 128.8, 128.9, 129.6, 130.5, 131.7, 133.7, 139.1, 153.8,
158.5, 189.7; HRMS (ESI) calcd for [M+H]+ C25H26NO3: 388.1913,
found: 388.1908.
5.1.4.33.
(E)-3-(1-(3-Fluorobenzyl)-1H-indol-6-yl)-1-(5-meth-
oxy-2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(35). The reaction was carried out following the general proce-
dure B with 35a (189 mg, 1 mmol) to give 35 as a yellow solid
(182 mg, 39%). 1H NMR (400 MHz, CDCl3) d: 1.45 (s, 6H), 3.88
(s, 3H), 5.35 (s, 2H), 5.60 (d, 1H, J = 10.0 Hz), 6.50 (d, 1H,
J = 8.8 Hz), 6.59 (s, 1H), 6.68 (d, 1H, J = 10.0 Hz), 6.75 (d, 1H,
J = 8.8 Hz), 6.87 (d, 1H, J = 8.0 Hz), 6.96 (t, 1H, J = 8.0 Hz),
7.26–7.30 (m, 3H), 7.44–7.46 (m, 2H), 7.64–7.71 (m, 2H), 7.77
(d, 1H, J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0,
49.7, 55.8, 76.6, 102.6, 103.4, 110.4, 111.0, 113.4, 113.6, 114.7,
114.9, 116.8, 119.4, 121.5, 121.9, 122.1, 125.5, 128.7, 129.7,
130.3, 130.5, 131.7, 136.4, 139.7, 143.3, 153.6, 158.3, 190.1;
HRMS (ESI) calcd for [M+H]+ C30H27FNO3: 468.1975, found:
468.1975.
5.1.4.38. (E)-3-(1-(3-Fluorobenzyl)-1H-indol-7-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(40). The
reaction was carried out following the general procedure B with
40a (189 mg, 1 mmol) to give 40 as a yellow solid (135 mg, 29%).
1H NMR (400 MHz, CDCl3) d: 1.45 (s, 6H), 3.89 (s, 3H), 5.53 (s, 2H),
5.60 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 8.8 Hz), 6.62 (d, 1H,
J = 2.8 Hz), 6.67 (d, 1H, J = 10.0 Hz), 6.98–6.99 (m, 2H), 7.12–7.16
(m, 2H), 7.18–7.22 (m, 2H), 7.39 (d, 1H, J = 8.0 Hz), 7.45 (d, 1H,
J = 15.6 Hz), 7.65–7.70 (m, 2H), 8.13 (d, 1H, J = 15.6 Hz); 13C NMR
(CDCl3, 100 MHz) d: 28.0, 28.0, 52.6, 55.8, 77.0, 102.5, 103.5,
110.5, 112.9, 113.2, 114.5, 114.7, 116.7, 120.2, 121.6, 121.8, 121.8,
122.9, 128.8, 129.6, 130.4, 130.5, 130.9, 131.5, 133.9, 139.1, 140.8,
153.5, 158.3, 190.0; HRMS (ESI) calcd for [M+H]+ C30H27FNO3:
468.1975, found: 468.1980.
5.1.4.34. (E)-3-(1-(3-Chlorobenzyl)-1H-indol-6-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(36). The
reaction was carried out following the general procedure B with
36a (189 mg, 1 mmol) to give 36 as a yellow solid (237 mg,
49%). 1H NMR (400 MHz, CDCl3) d: 1.45 (s, 6H), 3.87 (s, 3H), 5.32
(s, 2H), 5.60 (d, 1H, J = 10.0 Hz), 6.50 (d, 1H, J = 8.8 Hz), 6.58 (d,
1H, J = 2.8 Hz), 6.68 (d, 1H, J = 10.0 Hz), 6.94 (d, 1H, J = 6.4 Hz),
7.10 (s, 1H), 7.19 (d, 1H, J = 6.4 Hz), 7.22 (d, 2H, J = 6.4 Hz), 7.44
(d, 2H, J = 6.4 Hz), 7.64–7.71 (m, 3H), 7.77 (d, 1H, J = 15.6 Hz);
13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 49.6, 55.8, 76.8, 102.7,
103.4, 110.4, 110.9, 116.8, 119.4, 121.5, 121.9, 124.6, 125.5,
126.6, 128.1, 128.7, 129.7, 130.2, 130.3, 130.5, 131.7, 134.9,
136.4, 139.2, 143.2, 153.6, 158.3, 190.1; HRMS (ESI) calcd for
[M+H]+ C30H27ClNO3: 484.1679, found: 484.1684.
5.1.4.39. (E)-3-(1-(3-Chlorobenzyl)-1H-indol-7-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(41). The
reaction was carried out following the general procedure B with
41a (189 mg, 1 mmol) to give 41 as a yellow solid (155 mg, 32%).
1H NMR (400 MHz, CDCl3) d: 1.45 (s, 6H), 3.88 (s, 3H), 5.55 (s, 2H),
5.59 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 8.8 Hz), 6.62 (d, 1H,
J = 2.8 Hz), 6.66 (d, 1H, J = 10.0 Hz), 6.87–6.89 (m, 2H), 7.08–7.15
(m, 3H), 7.21–7.24 (m, 1H), 7.39 (d, 1H, J = 8.0 Hz), 7.44 (d, 1H,
J = 15.6 Hz), 7.63 (d, 1H, J = 8.8 Hz), 7.68 (d, 1H, J = 8.0 Hz), 8.11 (d,
1H, J = 15.6 Hz); 13C NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 52.6,
55.8, 77.0, 102.6, 103.5, 110.5, 116.7, 120.2, 121.6, 121.6, 121.8,
122.9, 124.5, 126.2, 127.9, 128.8, 129.6, 130.1, 130.5, 130.9, 131.6,
133.9, 134.8, 139.0, 140.2, 153.6, 158.3, 189.8; HRMS (ESI) calcd
for [M+H]+ C30H27ClNO3: 484.1679, found: 484.1674.
5.1.4.35. (E)-3-(1-(3-Bromobenzyl)-1H-indol-6-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(37). The
reaction was carried out following the general procedure B with
37a (189 mg, 1 mmol) to give 37 as a yellow solid (164 mg,
31%). 1H NMR (400 MHz, CDCl3) d: 1.45 (s, 6H), 3.87 (s, 3H), 5.31
(s, 2H), 5.60 (d, 1H, J = 10.0 Hz), 6.50 (d, 1H, J = 8.8 Hz), 6.58 (d,
1H, J = 2.8 Hz), 6.68 (d, 1H, J = 10.0 Hz), 6.97 (d, 1H, J = 8.0 Hz),
7.16 (t, 1H, J = 8.0 Hz), 7.18 (d, 1H, J = 2.8 Hz), 7.27 (s, 1H), 7.39
(d, 1H, J = 8.0 Hz), 7.44 (d, 2H, J = 8.0 Hz), 7.64 (d, 1H, J = 8.8 Hz),
7.68–7.72 (m, 2H), 7.77 (d, 1H, J = 15.6 Hz); 13C NMR (CDCl3,
100 MHz) d: 28.0, 28.0, 49.5, 55.8, 76.8, 102.7, 103.5, 110.4,
110.9, 116.8, 119.4, 121.5, 121.9, 123.0, 125.1, 125.5, 128.7,
129.5, 129.7, 130.3, 130.5, 130.5, 131.0, 131.7, 136.4, 139.5,
143.2, 153.6, 158.3, 190.1; HRMS (ESI) calcd for [M+H]+
C30H27BrNO3: 528.1174, found: 528.1170.
5.1.4.40. (E)-3-(1-(3-Bromobenzyl)-1H-indol-7-yl)-1-(5-methoxy-
2,2-dimethyl-2H-chromen-8-yl)prop-2-en-1-one
(42). The
reaction was carried out following the general procedure B with
42a (189 mg, 1 mmol) to give 42 as a yellow solid (206 mg, 39%).
1H NMR (400 MHz, CDCl3) d: 1.46 (s, 6H), 3.88 (s, 3H), 5.52 (s, 2H),
5.60 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 8.8 Hz), 6.61 (d, 1H,
J = 2.8 Hz), 6.66 (d, 1H, J = 10.0 Hz), 7.01 (d, 1H, J = 8.0 Hz), 7.13 (d,

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
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2H, J = 8.0 Hz), 7.22 (d, 1H, J = 8.0 Hz), 7.32 (d, 1H, J = 8.0 Hz), 7.40 (d,
1H, J = 8.0 Hz), 7.46 (d, 1H, J = 15.6 Hz), 7.53 (s, 1H), 7.65 (d, 1H,
J = 8.8 Hz), 7.68 (d, 1H, J = 8.0 Hz), 8.13 (d, 1H, J = 15.6 Hz); 13C
NMR (CDCl3, 100 MHz) d: 28.0, 28.0, 52.5, 55.8, 77.0, 102.6, 103.5,
110.5, 116.7, 120.2, 121.5, 121.8, 123.0, 125.0, 125.3, 128.8, 129.2,
129.5, 130.1, 130.4, 130.5, 130.9, 131.6, 133.9, 139.1, 140.4, 143.3,
153.6, 158.4, 189.9; HRMS (ESI) calcd for [M+H]+ C30H27BrNO3:
528.1174, found: 528.1182.
NMR (d6 DMSO, 400 MHz) d: 1.49 (s, 6H), 3.82 (s, 3H), 5.74 (d,
1H, J = 10.0 Hz), 6.51–6.54 (m, 2H), 6.64 (d, 1H, J = 10.0 Hz), 7.39
(s, 1H), 7.47 (d, 1H, J = 8.8 Hz), 7.55 (s, 2H), 7.65 (d, 1H,
J = 16.0 Hz), 7.69 (d, 1H, J = 16.0 Hz), 7.87 (s, 1H), 10.50 (s, 1H);
MS (ESI, m/z): 360.3 [M+H]+.
5.1.10. General procedure C for the synthesis of 49a–49d
The appropriate acid anhydride (5 mmol) was added to a solu-
tion of 48 (179.7 mg, 0.5 mmol) in pyridine. The reaction mixture
was stirred at room temperature for 24 h. The solvent was
removed under reduced pressure and the residue was purified by
silica gel chromatography.
5.1.5. 1-(2-Hydroxy-4-((tetrahydro-2H-pyran-2-yl)oxy)phenyl)-
ethanone (44)
A solution of DHP (18 mL, 197 mmol) in CH2Cl2 (100 mL) was
added dropwise to a solution of 1-(2,4-dihydroxyphenyl)ethanone
43 (10 g, 65 mmol) and PPTS (600 mg) at room temperature. The
resulting mixture was stirred for 4 h at room temperature and
monitored by TLC, then washed with saturated aqueous NaHCO3
solution, and extracted with CH2Cl2. The collected organic extracts
were dried over anhydrous NaSO4, filtered, and concentrated under
reduced pressure to give 44 as white solid, which was used in the
next step without further purification.
5.1.10.1. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl acetate (49a). The title compound was
synthesized according to the general procedure
C using 48
(179.7 mg, 0.5 mmol), acetic anhydride (610 L, 5 mmol), and pyr-
l
idine (5 mL). The product was purified by silica gel column chro-
matography to give 49a (78 mg, 39%) as a yellow solid. 1H NMR
(400 MHz, CDCl3) d: 1.51 (s, 6H), 2.35 (s, 3H), 3.81 (s, 3H), 5.72
(d, 1H, J = 10.0 Hz), 6.39 (d, 1H, J = 10.0 Hz), 6.53 (d, 1H,
J = 2.8 Hz), 6.71 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H, J = 2.8 Hz), 7.33 (d,
1H, J = 8.8 Hz), 7.49–7.54 (m, 2H), 7.58 (d, 1H, J = 8.0 Hz),
7.82–7.84 (m, 2H); 13C NMR (CDCl3, 100 MHz) d: 20.9, 28.1, 28.1,
33.0, 77.3, 102.1, 109.9, 114.5, 114.6, 116.2, 121.2, 123.2, 124.1,
126.5, 126.8, 128.8, 130.0, 130.2, 131.4, 137.9, 145.2, 148.7,
152.9, 168.8, 191.3; HRMS (ESI) calcd for [M+H]+ C25H24NO4:
402.1705, found: 402.1702.
5.1.6. 1-(2-((2-Methylbut-3-yn-2-yl)oxy)-4-((tetrahydro-2H-
pyran-2-yl)oxy)phenyl)ethanone (45)
To a solution of 44 (4.43 g, 10 mmol) in CH3CN (100 mL) at 0 °C
was added DBU (1.5 mL, 15 mmol), CuCl2Á2H2O (5 mg, 0.3% mol),
and 3-chloro-3-methyl-1-butyne (1.53 g, 15 mmol). The mixture
was stirred at 0 °C for 5 h and monitored by TLC. After completed,
1 N HCl (aq) was added to adjust pH = 2. The reaction mixture was
poured into ice-cold water and extracted with ethyl acetate
(3 Â 200 mL). The organic layer was dried over Na2SO4 and evapo-
rated under reduced pressure to give 45 as an red oil (40%), which
was used in the next step without further purification.
5.1.10.2. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl propionate (49b). The title compound
was synthesized according to the general procedure C using 48
(179.7 mg, 0.5 mmol), propionic anhydride (650 lL, 5 mmol), and
5.1.7. 1-(2,2-Dimethyl-5-((tetrahydro-2H-pyran-2-yl)oxy)-2H-
chromen-8-yl)ethanone (46)
A mixture of 45 (17.5 g) and pyridine (75 mL) was stirred at
120 °C for 12 h. After cooling to room temperature, the mixture
concentrated under reduced pressure to give 46 as black oil, which
was used in the next step without further purification.
pyridine (5 mL). The product was purified by silica gel column
chromatography to give 49b (137 mg, 66%) as a yellow solid. 1H
NMR (400 MHz, CDCl3) d: 1.45 (t, 3H, J = 6.8 Hz), 1.53 (s, 6H),
3.81 (s, 3H), 4.08 (q, 2H, J = 6.8 Hz), 5.62 (d, 1H, J = 10.0 Hz), 6.49
(d, 1H, J = 8.8 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.73 (d, 1H, J = 10.0 Hz),
7.07 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.0 Hz), 7.54 (d, 1H,
J = 8.0 Hz), 7.69–7.73 (m, 2H), 7.85–7.88 (m, 2H); 13C NMR
(100 MHz, CDCl3) d: 9.17, 27.65, 28.14, 28.14, 33.03, 77.25,
102.11, 109.87, 114.56, 114.67, 116.18, 121.24, 123.19, 124.18,
126.43, 126.80, 128.79, 130.02, 130.21, 131.30, 137.90, 145.15,
148.85, 152.94, 172.29, 191.27. HRMS (ESI) calcd for [M+H]+
C26H26NO4: 416.1862, found: 416.1860.
5.1.8. (E)-1-(2,2-Dimethyl-5-((tetrahydro-2H-pyran-2-yl)oxy)-
2H-chromen-8-yl)-3-(1-methyl-1H-indol-5-yl)prop-2-en-1-one
(47)
To a solution (140 mL) of 46 (3.02 g, 10 mmol) and 31a (8.40 g,
10 mmol) in methanol was added 50% KOH (20 mL, aq) and the
mixture was stirred for overnight. The reaction mixture was
poured into ice water and extracted with ethyl acetate (100 mL)
and washed with saturated brine. The organic layer was dried over
anhydrous magnesium sulfate. The solvent was evaporated under
reduced pressure and the residue was purified by silica gel column
chromatography to give 47 as a yellow solid (51%). 1H NMR (CDCl3,
400 MHz) d: 1.52 (s, 3H), 1.53 (s, 3H), 1.57–2.08 (m, 6H), 3.62–3.65
(m, 1H), 3.81 (s, 3H), 3.85–3.90 (m, 1H), 5.51–5.53 (m, 1H), 5.64 (d,
1H, J = 10.0 Hz), 6.52 (s, 1H), 6.75 (t, 2H, J = 8.8 Hz), 7.07 (s, 1H),
7.32 (d, 1H, J = 8.8 Hz), 7.54 (d, 1H, J = 8.8 Hz), 7.64–7.68 (m, 2H),
7.83–7.87 (m, 2H); MS (ESI, m/z): 444.5 [M+H]+.
5.1.10.3. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl isobutyrate (49c). The title compound
was synthesized according to the general procedure C using 48
(179.7 mg, 0.5 mmol), isobutyric anhydride (400 lL, 5 mmol), and
pyridine (5 mL). The product was purified by silica gel column chro-
matography to give 49c (136 mg, 63%) as a yellow solid. 1H NMR
(400 MHz, CDCl3) d: 1.35 (d, 6H, J = 7.2 Hz), 1.51 (s, 6H), 2.87 (hep-
tet, 1H, J = 7.2 Hz), 3.81 (s, 3H), 5.71 (d, 1H, J = 10.0 Hz), 5.36 (d, 1H,
J = 10.0 Hz), 6.53 (d, 1H, J = 2.8 Hz), 6.69 (d, 1H, J = 8.8 Hz), 7.07 (d,
1H, J = 2.8 Hz), 7.33 (d, 1H, J = 8.8 Hz), 7.50–7.54 (m, 2H), 7.58 (d,
1H, J = 8.8 Hz), 7.81–7.84 (m, 2H); 13C NMR (100 MHz, CDCl3) d:
19.1, 19.1, 28.2, 28.2, 33.0, 34.3, 77.3, 102.1, 109.9, 114.5, 114.7,
116.1, 121.2, 123.2, 124.2, 126.4, 126.8, 128.8, 130.0, 130.2, 131.3,
137.9, 145.2, 149.0, 153.0, 174.9, 191.3; HRMS (ESI) calcd for
[M+H]+ C27H28NO4: 430.2018, found: 430.2012.
5.1.9. (E)-1-(5-Hydroxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
methyl-1H-indol-5-yl)prop-2-en-1-one (48)
To a solution of 47 (6.65 g, 15 mmol) in CH3OH (150 mL) and
THF (150 mL) at room temperature was added pTsOH (258 mg,
1.5 mmol). The resulting mixture was stirred at 60 °C for 1 h. After
cooling to room temperature, the mixture concentrated under re-
duced. The residue was dissolved in EtOAc (300 mL) and washed
with water, brine, dried over anhydrous Na2SO4, and concentrated
under reduce pressure to give a yellow solid 48 (5.0 g, 93%). 1H
5.1.10.4. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl pentanoate (49d). The title compound
was synthesized according to the general procedure C using 48
(179.7 mg, 0.5 mmol), pentanoic anhydride (500 lL, 5 mmol), and

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G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
pyridine (5 mL). The product was purified by silica gel column
chromatography to give 49d (156 mg, 70%) as a yellow solid. 1H
NMR (400 MHz, CDCl3) d: 1.00 (t, 3H, J = 7.2 Hz), 1.42 (sext, 2H,
J = 7.2 Hz), 1.51 (s, 6H), 1.77 (quint, 2H, J = 7.2 Hz), 2.61 (t, 2H,
J = 7.2 Hz), 3.81 (s, 3H), 5.71 (d, 1H, J = 10.0 Hz), 5.37 (d, 1H,
J = 10.0 Hz), 6.53 (d, 1H, J = 2.8 Hz), 6.70 (d, 1H, J = 8.8 Hz), 7.07
(d, 1H, J = 2.8 Hz), 7.33 (d, 1H, J = 8.8 Hz), 7.49–7.53 (m, 2H), 7.58
(d, 1H, J = 8.8 Hz), 7.81–7.85 (m, 2H); 13C NMR (100 MHz, CDCl3)
d: 13.8, 22.3, 27.0, 28.1, 28.1, 33.0, 34.0, 77.2, 102.1, 109.9, 114.6,
114.7, 116.2, 121.2, 123.2, 124.2, 126.4, 126.8, 128.8, 130.0,
130.2, 131.3, 137.9, 145.1, 148.9, 152.9, 171.6, 191.3; HRMS (ESI)
calcd for [M+H]+ C28H30NO4: 444.2175, found: 444.2171.
(100 MHz, CDCl3) d: 10.6, 22.6, 28.1, 28.1, 31.0, 33.0, 69.9, 102.0,
104.3, 109.8, 110.5, 117.0, 121.2, 121.9, 123.0, 124.7, 127.2,
128.5, 128.8, 129.9, 131.6, 137.7, 143.8, 153.6, 157.7, 190.4; HRMS
(ESI) calcd for [M+H]+ C26H28NO3: 402.2069, found: 402.2065.
5.1.11.4. (E)-1-(5-Butoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
methyl-1H-indol-5-yl)prop-2-en-1-one (49h). The title com-
pound was synthesized according to the general procedure D using
1-iodobutane (114 lL, 0.75 mmol), 48 (179.7 mg, 0.5 mmol),
Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The product was
purified by silica gel column chromatography to give 49h
(160 mg, 77%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
0.99 (t, 3H, J = 7.2 Hz), 1.49 (sext, 2H, J = 7.2 Hz), 1.52 (s, 6H),
1.80 (quint, 2H, J = 7.2 Hz), 3.80 (s, 3H), 4.04 (t, 2H, J = 7.2 Hz),
5.61 (d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 8.8 Hz), 6.52 (d, 1H,
J = 2.8 Hz), 6.72 (d, 1H, J = 10.0 Hz), 7.06 (d, 1H, J = 2.8 Hz), 7.32
(d, 1H, J = 8.8 Hz), 7.54 (d, 1H, J = 8.8 Hz), 7.69 (d, 1H, J = 8.8 Hz),
7.69 (d, 1H, J = 16.0 Hz), 7.85–7.88 (m, 2H); 13C NMR (100 MHz,
CDCl3) d: 13.9, 19.3, 28.1, 28.1, 31.0, 31.3, 33.0, 68.2, 102.0,
104.2, 109.8, 110.5, 117.0, 121.2, 121.9, 123.0, 124.6, 127.2,
128.5, 128.8, 129.9, 131.6, 137.7, 143.7, 153.6, 157.8, 190.3; HRMS
(ESI) calcd for [M+H]+ C27H30NO3: 416.2226, found: 416.2228.
5.1.11. General procedure D for the synthesis of 49e–49j
A
mixture of appropriate alkyl halide (0.75 mmol), 48
(179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone
(5 mL) was stirred at room temperature for overnight. The mixture
was filtered to remove Cs2CO3 and the filtrate was concentrated in
vacuo. The residue was purified by silica gel chromatography.
5.1.11.1. (E)-1-(5-Ethoxy-2,2-dimethyl-2H-chromen-8-yl)-3-(1-
methyl-1H-indol-5-yl)prop-2-en-1-one (49e). The title com-
pound was synthesized according to the general procedure D using
iodoethane (125 lL, 0.75 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3
(325 mg, 1 mmol) and acetone (5 mL). The product was purified
by silica gel column chromatography to give 49e (143 mg, 74%)
as a yellow solid. 1H NMR (400 MHz, CDCl3) d: 1.45 (t, 3H,
J = 6.8 Hz), 1.52 (s, 6H), 3.80 (s, 3H), 4.08 (q, 2H, J = 6.8 Hz), 5.62
(d, 1H, J = 10.0 Hz), 6.49 (d, 1H, J = 8.8 Hz), 6.52 (d, 1H, J = 2.8 Hz),
6.72 (d, 1H, J = 10.0 Hz), 7.07 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H,
J = 8.8 Hz), 7.54 (d, 1H, J = 8.8 Hz), 7.69–7.73 (m, 2H), 7.85–7.88
(m, 2H); 13C NMR (100 MHz, CDCl3) d: 14.8, 28.1, 28.1, 31.0, 33.0,
64.1, 102.0, 104.2, 109.8, 110.5, 117.0, 121.2, 121.9, 123.0, 124.6,
127.2, 128.6, 128.8, 129.9, 131.6, 137.7, 143.8, 153.6, 157.6,
190.4; HRMS (ESI) calcd for [M+H]+ C25H26NO3: 388.1913, found:
388.1915.
5.1.11.5. (E)-1-(2,2-Dimethyl-5-(pentyloxy)-2H-chromen-8-yl)-
3-(1-methyl-1H-indol-5-yl)prop-2-en-1-one (49i). The title
compound was synthesized according to the general procedure D
using 1-iodopentane (130 lL, 0.75 mmol), 48 (179.7 mg,
0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The
product was purified by silica gel column chromatography to give
49i (170 mg, 79%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
0.95 (t, 3H, J = 7.2 Hz), 1.37–1.49 (m, 4H), 1.53 (s, 6H), 1.82 (quint,
2H, J = 7.2 Hz), 3.80 (s, 3H), 4.03 (t, 2H, J = 7.2 Hz), 5.62 (d, 1H,
J = 10.0 Hz), 6.48 (d, 1H, J = 8.8 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.72
(d, 1H, J = 10.0 Hz), 7.06 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz),
7.54 (d, 1H, J = 8.8 Hz), 7.69–7.73 (m, 2H), 7.85–7.88 (m, 2H); 13C
NMR (100 MHz, CDCl3) d: 14.1, 22.5, 28.1, 28.1, 28.2, 28.9, 29.7,
33.0, 68.5, 102.0, 104.2, 109.8, 110.5, 117.0, 121.2, 121.9, 123.0,
124.7, 127.2, 128.5, 128.8, 129.9, 131.6, 137.7, 143.7, 153.6,
157.8, 190.3; HRMS (ESI) calcd for [M+H]+ C28H32NO3: 430.2382,
found: 430.2386.
5.1.11.2. (E)-1-(5-Isopropoxy-2,2-dimethyl-2H-chromen-8-yl)-
3-(1-methyl-1H-indol-5-yl)prop-2-en-1-one (49f). The title
compound was synthesized according to the general procedure D
using 2-iodopropane (98 lL, 0.75 mmol), 48 (179.7 mg, 0.5 mmol),
Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The product was
purified by silica gel column chromatography to give 49f
(158 mg, 79%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
1.36 (d, 6H, J = 6.0 Hz), 1.52 (s, 6H), 3.81 (s, 3H), 4.63 (heptet, 1H,
J = 6.0 Hz), 5.61 (d, 1H, J = 10.0 Hz), 6.50–6.52 (m, 2H), 6.71 (d,
1H, J = 10.0 Hz), 7.07 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz),
7.54 (d, 1H, J = 8.8 Hz), 7.68 (d, 1H, J = 8.8 Hz), 7.69 (d, 1H,
J = 16.0 Hz), 7.85–7.89 (m, 2H); 13C NMR (100 MHz, CDCl3) d:
22.2, 22.2, 28.1, 28.1, 31.0, 33.0, 70.7, 102.0, 105.6, 109.8, 111.3,
117.2, 121.2, 121.6, 122.9, 124.7, 127.2, 128.4, 128.8, 129.9,
131.4, 137.7, 143.7, 153.8, 156.8, 190.3; HRMS (ESI) calcd for
[M+H]+ C26H28NO3: 402.2069, found: 402.2061.
5.1.11.6. (E)-1-(5-Isobutoxy-2,2-dimethyl-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-5-yl)prop-2-en-1-one (49j). The title com-
pound was synthesized according to the general procedure D using
1-iodo-2-methylpropane (115 lL, 0.75 mmol), 48 (179.7 mg,
0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The
product was purified by silica gel column chromatography to give
49j (133 mg, 64%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
1.05 (d, 6H, J = 6.8 Hz), 1.53 (s, 6H), 2.10–2.17 (m, 1H, J = 6.8 Hz),
3.79–3.81 (m, 5H), 5.62 (d, 1H, J = 10.0 Hz), 6.48 (d, 1H,
J = 8.8 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.73 (d, 1H, J = 10.0 Hz), 7.07
(d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.54 (d, 1H, J = 8.8 Hz),
7.69–7.73 (m, 2H), 7.85–7.88 (m, 2H); 13C NMR (100 MHz, CDCl3)
d: 19.3, 19.3, 28.1, 28.1, 28.4, 31.0, 33.0, 74.7, 102.0, 104.3, 109.8,
110.5, 117.0, 121.2, 121.9, 122.9, 124.7, 127.2, 128.5, 128.8,
129.9, 131.6, 137.7, 143.8, 153.6, 157.8, 190.3; HRMS (ESI) calcd
for [M+H]+ C27H30NO3: 416.2226, found: 416.2226.
5.1.11.3. (E)-1-(2,2-Dimethyl-5-propoxy-2H-chromen-8-yl)-3-
(1-methyl-1H-indol-5-yl)prop-2-en-1-one (49g). The
compound was synthesized according to the general procedure D
using 1-iodopropane (95 L, 0.75 mmol), 48 (179.7 mg, 0.5 mmol),
title
l
Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The product was
purified by silica gel column chromatography to give 49g
(138 mg, 69%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
1.06 (t, 3H, J = 7.2 Hz), 1.53 (s, 6H), 1.80 (sext, 2H, J = 7.2 Hz),
3.80 (s, 3H), 3.99 (t, 2H, J = 7.2 Hz), 5.61 (d, 1H, J = 10.0 Hz), 6.48
(d, 1H, J = 8.8 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.73 (d, 1H, J = 10.0 Hz),
7.06 (d, 1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.54 (d, 1H,
J = 8.8 Hz), 7.69–7.73 (m, 2H), 7.85–7.88 (m, 2H); 13C NMR
5.1.12. General procedure E for the synthesis of 49k–49r
A mixture of appropriate aryl sulfonyl chloride (0.6 mmol), 48
(179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone
(5 mL) was stirred at room temperature for overnight. The mixture
was filtered to remove Cs2CO3 and the filtrate was concentrated in
vacuo. The residue was purified by silica gel chromatography.

G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
2077
5.1.12.1. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl 3,5-difluorobenzenesulfonate
J = 16.0 Hz), 7.83 (s, 1H); 13C NMR (100 MHz, CDCl3) d: 21.8, 28.0,
28.0, 33.0, 77.3, 102.1, 109.9, 114.7, 116.0, 116.2, 121.2, 123.3,
123.8, 126.6, 127.5, 128.6, 128.6, 128.6, 128.8, 130.0, 130.0,
130.1, 131.5, 132.2, 138.0, 145.6, 145.7, 147.3, 152.8, 191.2; HRMS
(ESI) calcd for [M+H]+ C30H28NO5S: 514.1688, found: 514.1685.
(49k). The title compound was synthesized according to the
general procedure E using 3,5-difluorobenzene-1-sulfonyl chlo-
ride (127.5 mg, 0.6 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3
(325 mg, 1 mmol) and acetone (5 mL). The product was purified
by silica gel column chromatography to give 49k (132 mg, 49%)
as a yellow solid. 1H NMR (400 MHz, CDCl3) d: 1.43 (s, 6H),
3.81 (s, 3H), 5.64 (d, 1H, J = 10.0 Hz), 6.33 (d, 1H, J = 10.0 Hz),
6.53 (d, 1H, J = 2.8 Hz), 6.69 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H,
J = 2.8 Hz), 7.13–7.17 (m, 1H), 7.33 (d, 1H, J = 8.8 Hz), 7.40–7.45
(m, 3H), 7.50 (d, 2H, J = 8.8 Hz), 7.78–7.83 (m, 2H); 13C NMR
(100 MHz, CDCl3) d: 27.9, 27.9, 33.1, 77.4, 102.2, 109.9, 110.2,
112.2, 112.4, 114.5, 115.7, 115.8, 121.3, 123.4, 123.7, 126.5,
128.1, 128.8, 130.1, 130.2, 132.1, 138.0, 138.3, 146.0, 146.8,
152.8, 161.6, 164.1, 191.1; HRMS (ESI) calcd for [M+H]+
C29H24F2NO5S: 536.1343, found: 536.1348.
5.1.12.5. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acryloyl)-
2H-chromen-5-yl 3-methoxybenzenesulfonate (49o). The title
compound was synthesized according to the general procedure E
using 3-methoxybenzene-1-sulfonyl chloride (142 mg, 0.6 mmol),
48 (179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone
(5 mL). The product was purified by silica gel column chromatogra-
phy to give 49o (183 mg, 69%) as
a
yellow solid. 1H NMR
(400 MHz, CDCl3) d: 1.41 (s, 6H), 3.81 (s, 3H), 3.83 (s, 3H), 5.60 (d,
1H, J = 10.0 Hz), 6.38 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 2.8 Hz),
6.66 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H, J = 2.8 Hz), 7.18–7.21 (m, 1H),
7.32 (d, 2H, J = 8.8 Hz), 7.41–7.45 (m, 3H), 7.47 (d, 1H, J = 8.8 Hz),
7.50 (d, 1H, J = 8.8 Hz), 7.77 (d, 1H, J = 16.0 Hz), 7.83 (s, 1H); 13C
NMR (100 MHz, CDCl3) d: 28.0, 28.0, 31.0, 33.1, 55.8, 102.1, 109.9,
112.8, 114.6, 116.0, 116.1, 120.8, 121.1, 121.2, 123.3, 123.8, 126.6,
127.6, 128.8, 130.0, 130.1, 130.4, 131.6, 136.2, 138.0, 145.7, 147.3,
152.8, 160.0, 191.2; HRMS (ESI) calcd for [M+H]+ C30H28NO6S:
530.1637, found: 530.1633.
5.1.12.2. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl 4-bromo-2-(trifluoromethyl)benzene-
sulfonate (49l). The title compound was synthesized according
to the general procedure E using 4-bromo-2-(trifluoromethyl)ben-
zene-1-sulfonyl chloride (194 mg, 0.6 mmol), 48 (179.7 mg,
0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone (5 mL). The
product was purified by silica gel column chromatography to give
49l (157 mg, 48%) as a yellow solid. 1H NMR (400 MHz, CDCl3) d:
1.44 (s, 6H), 3.81 (s, 3H), 5.68 (d, 1H, J = 10.0 Hz), 6.47 (d, 1H,
J = 10.0 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.55 (d, 1H, J = 8.8 Hz), 7.08
(d, 1H, J = 2.8 Hz), 7.33 (d, 1H, J = 8.8 Hz), 7.40 (d, 1H, J = 16.0 Hz),
7.44 (d, 1H, J = 8.8 Hz), 7.50 (d, 2H, J = 8.8 Hz), 7.77 (d, 1H,
J = 16.0 Hz), 7.83 (s, 1H), 7.84 (d, 1H, J = 8.8 Hz), 7.91 (d, 1H,
J = 8.8 Hz), 8.12 (s, 1H); 13C NMR (100 MHz, CDCl3) d: 28.0, 28.0,
33.1, 57.3, 102.2, 107.7, 109.9, 113.9, 115.1, 115.8, 116.2, 121.2,
123.3, 123.7, 126.5, 127.8, 128.8, 129.0, 130.1, 130.1, 131.8,
133.2, 138.0, 145.9, 147.0, 152.6, 152.9, 158.3, 191.1; HRMS (ESI)
calcd for [M+H]+ C30H24BrF3NO5S: 646.0511, found: 646.05113.
5.1.12.6. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acryloyl)-
2H-chromen-5-yl 4-isopropylbenzenesulfonate (49p). The title
compound was synthesized according to the general procedure E
using 4-isopropylbenzene-1-sulfonyl chloride (131 mg, 0.6 mmol),
48 (179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and acetone
(5 mL). The product was purified by silica gel column chromatogra-
phy to give 49p (162 mg, 60%) as
a
yellow solid. 1H NMR
(400 MHz, CDCl3) d: 1.26 (d, 6H, J = 6.8 Hz), 1.39 (s, 6H), 3.00 (heptet,
1H, J = 6.0 Hz), 3.81 (s, 3H), 5.55 (d, 1H, J = 10.0 Hz), 6.35 (d, 1H,
J = 10.0 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.69 (d, 1H, J = 8.8 Hz), 7.08 (d,
1H, J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.37 (d, 2H, J = 8.8 Hz), 7.41
(d, 1H, J = 15.6 Hz), 7.47 (d, 1H, J = 8.8 Hz), 7.50 (d, 1H, J = 8.8 Hz),
7.77 (d, 2H, J = 8.8 Hz), 7.78 (d, 1H, J = 15.6 Hz), 7.83 (s, 1H); 13C
NMR (100 MHz, CDCl3) d: 23.7, 23.7, 28.0, 28.0, 33.1, 34.3, 77.2,
102.1, 109.9, 114.8, 116.0, 116.1, 121.2, 123.3, 123.9, 126.6, 127.5,
127.5, 127.5, 128.8, 128.8, 128.8, 130.0, 130.1, 131.3, 132.4, 138.0,
145.6, 147.3, 152.8, 156.4, 191.2; HRMS (ESI) calcd for [M+H]+
C32H32NO5S: 542.2001, found: 542.2006.
5.1.12.3. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl 2,3,4,5,6-pentafluorobenzenesulfonate
(49m). The title compound was synthesized according to the
general procedure E using 2,3,4,5,6-pentafluorobenzene-1-sulfonyl
chloride (160 mg, 0.6 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3
(325 mg, 1 mmol) and acetone (5 mL). The product was purified
by silica gel column chromatography to give 49m (149 mg, 51%)
as a yellow solid. 1H NMR (400 MHz, CDCl3) d: 1.46 (s, 6H), 3.81
(s, 3H), 5.76 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H, J = 2.8 Hz), 6.55 (d,
1H, J = 10.0 Hz), 6.81 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H, J = 2.8 Hz),
7.32 (d, 1H, J = 8.8 Hz), 7.38 (d, 1H, J = 16.0 Hz), 7.50 (d, 1H,
J = 8.8 Hz), 7.52 (d, 1H, J = 8.8 Hz), 7.76 (d, 1H, J = 16.0 Hz), 7.82 (s,
1H); 13C NMR (100 MHz, CDCl3) d: 27.9, 27.9, 33.0, 77.6, 102.2,
109.9, 113.6, 115.5, 115.6, 121.3, 123.4, 123.6, 126.5, 128.5, 128.8,
130.2, 130.4, 132.5, 132.6, 138.0, 146.2, 146.3, 152.9, 191.0; HRMS
(ESI) calcd for [M+H]+ C29H21F5NO5S: 590.1061, found: 590.1059.
5.1.12.7. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl
(49q). The title compound was synthesized according to the gen-
eral procedure using 3-(trifluoromethyl)benzene-1-sulfonyl
3-(trifluoromethyl)benzenesulfonate
E
chloride (147 mg, 0.6 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3
(325 mg, 1 mmol) and acetone (5 mL). The product was purified
by silica gel column chromatography to give 49p (201 mg, 71%)
as a yellow solid. 1H NMR (400 MHz, CDCl3) d: 1.44 (s, 6H), 3.81
(s, 3H), 5.66 (d, 1H, J = 10.0 Hz), 6.50–6.54 (m, 3H), 7.08 (d, 1H,
J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.41 (d, 1H, J = 15.6 Hz), 7.42
(d, 1H, J = 8.8 Hz), 7.50 (d, 1H, J = 8.8 Hz), 7.72 (t, 1H, J = 8.0 Hz),
7.77 (d, 1H, J = 16.0 Hz), 7.83–7.85 (m, 2H), 8.00 (d, 1H,
J = 8.0 Hz), 8.09 (d, 1H, J = 8.0 Hz); 13C NMR (100 MHz, CDCl3) d:
28.0, 28.0, 33.1, 77.5, 102.1, 109.9, 114.3, 116.0, 116.2, 121.2,
123.3, 123.8, 126.5, 127.8, 128.8, 128.9, 130.0, 130.1, 131.9,
132.5, 132.9, 134.0, 134.6, 138.0, 145.9, 147.0, 152.9, 191.2;
HRMS (ESI) calcd for [M+H]+ C30H25F3NO5S: 568.1406, found:
568.1414.
5.1.12.4. (E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acry-
loyl)-2H-chromen-5-yl 4-methylbenzenesulfonate (49n). The
title compound was synthesized according to the general proce-
dure
E using 4-methylbenzene-1-sulfonyl chloride (114 mg,
0.6 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol)
and acetone (5 mL). The product was purified by silica gel column
chromatography to give 49n (174 mg, 68%) as a yellow solid. 1H
NMR (400 MHz, CDCl3) d: 1.40 (s, 6H), 2.45 (s, 3H), 3.81 (s, 3H),
5.59 (d, 1H, J = 10.0 Hz), 6.40 (d, 1H, J = 10.0 Hz), 6.52 (d, 1H,
J = 2.8 Hz), 6.63 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H, J = 2.8 Hz), 7.32–
7.34 (m, 3H), 7.41 (d, 1H, J = 16.0 Hz), 7.45 (d, 1H, J = 8.8 Hz),
7.50 (d, 1H, J = 8.8 Hz), 7.74 (d, 2H, J = 8.0 Hz), 7.78 (d, 1H,
5.1.12.8.
(E)-2,2-Dimethyl-8-(3-(1-methyl-1H-indol-5-yl)acryloyl)-
2H-chromen-5-yl 2-methoxy-4-nitrobenzenesulfonate (49r). The
title compound was synthesized according to the general procedure E
using
2-methoxy-4-nitrobenzene-1-sulfonyl
chloride
(151 mg,

2078
G. Wang et al. / Bioorg. Med. Chem. 22 (2014) 2060–2079
0.6 mmol), 48 (179.7 mg, 0.5 mmol), Cs2CO3 (325 mg, 1 mmol) and ace-
tone (5 mL). The product was purified by silica gel column chromatogra-
phy to give 49r (176 mg, 71%) as a yellow solid. 1HNMR(400 MHz,CDCl3)
d: 1.44 (s, 6H), 3.81 (s, 3H), 4.12 (s, 3H), 5.71 (d, 1H, J = 10.0 Hz),6.52(d,1H,
J = 2.8 Hz), 6.61 (d, 1H, J = 10.0 Hz), 6.69 (d, 1H, J = 8.8 Hz), 7.08 (d, 1H,
J = 2.8 Hz), 7.32 (d, 1H, J = 8.8 Hz), 7.39 (d, 1H, J = 16.0 Hz), 7.45 (d, 1H,
J = 8.8 Hz), 7.49 (d, 1H, J = 8.8 Hz), 7.76 (d, 1H, J = 16.0 Hz), 7.82 (s, 1H),
7.88–7.91 (m, 2H), 8.06 (d, 1H, J = 8.8 Hz); 13C NMR (100 MHz, CDCl3) d:
28.0, 28.0, 31.0, 33.1, 77.5, 102.2, 109.9, 114.3, 115.9, 116.1, 121.3,
123.4, 123.7, 126.5, 128.0, 128.8, 129.9, 130.1, 130.1, 132.1, 132.2, 132.2,
133.0, 134.3, 135.5, 138.0, 146.0, 146.8, 152.9, 191.1; HRMS (ESI) calcd
for [M+H]+ C30H27N2O8S: 575.1488, found: 575.1484.
a-tubulin followed by fluorescence antibody. Nuclei were labeled
with DAPI. Cells were visualized using a fluorescence microscope.
5.2.6. The in vivo antitumor activity
Six weeks old, female BALB/c nude mice (16–18 g) were pur-
chased from the animal breeding laboratories of Sichuan University
Animal Center (Sichuan, Chengdu, China). HepG2 cells (1 Â 107)
were collected in 0.1 mL of DMEM and these cell suspensions were
inoculated into the right gluteal region of each nude mouse. Once
the HepG2 xenografts reached a size of 100 mm3, twenty-four fe-
male BALB/c nude mice were randomly divided into four groups:
a vehicle control group, a positive group, and two tested groups.
The mice in the test group received tail intravenous once every
other day at the dosage of 15 mg/kg or 30 mg/kg of 49b for 21 days.
The positive group received tail intravenous once a day of 5-Fu at a
dose of 5 mg/kg, and the control group received injection of vehicle
alone following the time schedule for the test groups. Tumor bur-
den was measured every 3 days with a caliper (calculated volume
5.2. Biological evaluation
5.2.1. Cytotoxicity assay
1 Â 104 cells per well were plated in 96-well culture plates and
incubated for 24 h. After incubation, Tetrazolium dye [3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazo-lium bromide, MTT]
(mm3) =
p
/6  length  width  width). After completing the
treatment schedule, tumor-bearing mice were euthanized.
solution (20
was incubated until a purple precipitate was visible. Then, the pre-
cipitates were dissolved in 150 L of DMSO, after the medium was
lL of 5 mg/mL) in PBS was added to each well. This
l
Acknowledgments
carefully removed, shaken mechanically for 10 min, and then
absorbance values at a wavelength of 570 nm were determined
with the Spectramax M5 Microtiter Plate Luminometer (Molecular
Devices, USA). Values were calculated using percentage of growth
versus untreated control.
The authors greatly appreciate the financial support from
National Key Programs of China during the 12th Five-Year Plan
Period (2012ZX09103101-009) and National Natural Science
Foundation of China (81373283).
References and notes
5.2.2. Tubulin polymerization assay
MAP-rich tubulin (2 mg/mL) was preincubated in polymeriza-
tion buffer (0.1 M MES, 1 mM EGTA, pH 6.5, 0.5 mM MgCl2) with
various compound at 4 °C for 2 min before the addition of 1 mM
GTP. The samples were then rapidly warmed to 37 °C in a 96-well
plate thermostatically controlled Spectramax M5 Microtiter Plate
Luminometer, and the change in absorbance at 350 nm was period-
ically measured. Colchicine and Paclitaxel were used as reference.
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