Synthesis and crystal structure of chalcones as well as on cytotoxicity and antibacterial properties

Article abstract of DOI:10.1007/s00044-011-9549-9

A series of chalcones derivatives were synthesized and evaluated for cytotoxic and antibacterial activities in vitro. These modifications changed their bioactivity profile and indicated a combination of SAR analysis toward the substituents in rings A and

Full text of DOI:10.1007/s00044-011-9549-9

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:444–452
DOI 10.1007/s00044-011-9549-9
ORIGINAL RESEARCH
Synthesis and crystal structure of chalcones as well
as on cytotoxicity and antibacterial properties
•
Jianzhang Wu Cong Wang Yuepiao Cai Jing Peng
•
•
•
•
Donglou Liang Yunjie Zhao Shulin Yang Xiaokun Li
•
•
•
•
Xiaoping Wu Guang Liang
Received: 21 August 2010 / Accepted: 4 January 2011 / Published online: 18 January 2011
Ó Springer Science+Business Media, LLC 2011
Abstract A series of chalcones derivatives were synthe-
sized and evaluated for cytotoxic and antibacterial activi-
ties in vitro. These modifications changed their bioactivity
profile and indicated a combination of SAR analysis
toward the substituents in rings A and B of chalcones.
Compounds 2, 6–8, 14–17, and 32 exhibited good cyto-
toxic properties against two human cancer cell lines HT29
and SGC7901. Compounds 16 and 17 showed high anti-
bacterial activity toward 14 clinically isolated multidrug-
resistant strains. Subsequently, the structure of bi-bioactive
compound 16 was determined using single-crystal X-ray
diffraction. This study presents a few novel leading com-
pounds for the development of potential antitumor and
antibacterial agents.
Introduction
Chalcones, with the common skeleton of 1,3-diaryl-2-
propen-1-ones, are essential intermediate compounds in
flavonoid biosynthesis in plants (Nowakowska, 2007).
Chemically, they are open-chained molecules consisting of
two aromatic rings linked by a three-carbon a,b-unsatu-
rated carbonyl system. Extensive investigations have
demonstrated active biological properties of natural and
synthetic chalcones, including antiinflammatory (Tanaka
et al., 2009; Park et al., 2009; Heidari et al., 2009; Ko
et al., 2003), antioxidant (Padhye et al., 2009; Ghosh et al.,
2009), antimalarial (Bhattacharya et al., 2009; Tomar
et al., 2010; Dominguez et al., 2005), antitumoral (Rat-
kovic et al., 2010; Hua et al., 2009; Henmi et al., 2009;
Tang et al., 2008; Kamal et al., 2008; Boumendjel et al.,
2008; Rao et al., 2004), and antibacterial (Batovska et al.,
2009; Nowakowska et al., 2008; Liu et al., 2008; Avila
et al., 2008; Nielsen et al., 2005) properties in vitro and in
vivo. Among currently identified anti-tumor agents, chal-
cones represent an important class of naturally small
molecules useful in cancer chemotherapy (Ratkovic et al.,
2010; Boumendjel et al., 2008; Kumar et al., 2003). It is
demonstrated that chalcones exhibit antimitotic properties
caused by inhibition of tubulin polymerization by attaching
to the colchicine-binding site (Boumendjel et al., 2008).
Cancer and infective disease are two of the leading
causes of human death in developing as well as advanced
countries. Although many therapeutic strategies including
chemotherapy and radiotherapy are available, high sys-
temic toxicity and drug resistance limit the successful
outcomes in many cases. Therefore, novel treatment
approaches and therapeutic agents are urgently needed for
the cancer therapy and multi-drug-resistant infective dis-
ease. Among chalcones and their synthetic derivatives,
Keywords Chalcones ꢀ Synthesis ꢀ Cytotoxicity ꢀ
Antibacterial activity ꢀ Crystal structure
Jianzhang Wu, Cong Wang contribute equally to this work.
J. Wu ꢀ C. Wang ꢀ Y. Cai ꢀ J. Peng ꢀ D. Liang ꢀ Y. Zhao ꢀ
X. Li ꢀ X. Wu ꢀ G. Liang (&)
Bioorganic & Medicinal Chemistry Research Center,
School of Pharmacy, Wenzhou Medicinal College,
Wenzhou, Zhejiang 325035, People’s Republic of China
e-mail: cuiliang1234@gmail.com
J. Wu ꢀ S. Yang ꢀ X. Li ꢀ G. Liang
Institute of Biotechnology, Nanjing University of Science
and Technology, Nanjing 210094, People’s Republic of China
C. Wang ꢀ X. Wu
Institute of Tissue Transplantation and Immunology,
Jinan University, Guangzhou 510632,
People’s Republic of China
123

Med Chem Res (2012) 21:444–452
445
several compounds displayed cytotoxic activity toward
cultured tumor cells (Ratkovic et al., 2010; Hua et al.,
2009; Henmi et al., 2009; Tang et al., 2008; Kamal et al.,
2008; Boumendjel et al., 2008; Rao et al., 2004) and
inhibitory properties against pathogenic bacteria (Batovska
et al., 2009; Nowakowska et al., 2008; Liu et al., 2008;
Avila et al., 2008; Nielsen et al., 2005). They were also
effective in vivo as anti-tumor, chemopreventing, anti-
bacterial, and anti-inflammatory agents.
Results and discussion
Chemistry
An amount of 40 chalcones whose structures were shown in
Scheme 1 were synthesized by Claisene-Schmidt condensa-
tion between acetophenones (acetophenone, 40-aminoaceto-
phenone, 30-aminoacetophenone, 40-methoxyacetophenone,
20-hydroxyacetophenone, and 30,50-difluoroacetophenone)
and aryl aldehydes. As shown in Scheme 1, compounds 3, 12
and 16 were synthesized by reflux in acidic media using HCl
as catalyst, while other chalcones were synthesized at 5°C
with a catalytic amount of NaOH. All reactions were moni-
tored on the silica gel thin layer chromatography. The yields
of products were in the range of 10 and 95% after purifica-
tion. In general, the yields of reactions using NaOH as cat-
alyst were greater than that of reactions under HCl
To find the broad spectrum biologically active chal-
cones, we have previously described the anti-inflamma-
tory, antimicrobial, and antitumor activities of chalcone
analogs containing 5-C central linker (Liang et al. 2009).
As part of our ongoing research for potential anticancer
drug candidates, in the present study, a series of chal-
cones derivatives with 3-C central linker were synthesized
and tested for cytotoxicity and antibacterial activity in
vitro. Most compounds exhibited good cytotoxic proper-
ties against human cancer cell lines HT29 and SGC7901.
Several compounds displayed good antibacterial activity,
especially against multidrug-resistant gram-positive bac-
1
circumstance. Details of yields, melting points, H-NMR,
IR, and ESI–MS analysis are described in experimental
1
section. The H-NMR spectral evidence that the coupling
constants of double bonding hydrogens reached 15–16 Hz
confirmed the trans-conformation in the structures of all
chalcones. Before used to the biological experiments, com-
pounds were purified using re-crystallization or column
chromatography and were determined by HPLC method to
meet purity more than 98%.
teria. Subsequently,
a structure–activity relationship
analysis was also carried out to understand the structural
requirements for optimum activity and the most active
compound 16 was determined through single-crystal
X-ray diffraction.
Scheme 1 Design, chemical
structures, and general synthesis
of chalcones. Reagents and
conditions (i) HCl and reflux for
3, 12, and 16; (ii) 5°C and
NaOH for other compounds
O
R3
1,5-diaryl-1,4-pentadien-3-ones
Also called as mono-carbonyl analogues
of curcumin in our previous publications
R4
O
O
O
Chalcone
2
2
1
1
OHC
3
3
4
i or ii
R1
R2
4
A
B
R1
R2
A
B
5
5
LnHm
General structure of chalcones
Comp.
R1 in ring A R2 in ring B
Comp.
R1 in ring A
R2 in ring B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
4-NH2
4-OCH3
2-OH
3-NH2
3-F,5-F
4-NH2
4-NH2
H
4-NH2
3-NH2
4-OCH3
2-OH
3-F,5-F
4-NH2
4-OCH3
H
2-Cl,4-Cl
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
3-F, 5-F
4-NH2
4-OCH3
3-F, 5-F
4-NH2
3-NH2
4-OCH3
H
4-NH2
4-OCH3
4-NH2
4-OCH3
4-OCH3
2-OCH3, 4-OCH3
2-OCH3
2-OCH3
2-Cl,4-Cl
2-Cl,4-Cl
4-N(CH3)2
4-N(CH3)2
2-Cl
2-OCH3
2-OCH3, 3-OCH3
2-OCH3, 3-OCH3
2-OCH3, 3-OCH3
2-CF3
2-CF3
2-CF3
2-Br
2-Br
2-F, 4-F
2-Cl
4-OCH3
4-OCH3
4-OCH3
4-OCH3
4-OCH3
4-OCH3
2-F
2-F
4-OH
4-OH
3-OCH3, 4-OCH3 2-Cl,4-Cl
3-OCH3, 4-OCH3 4-N(CH3)2
3-OCH3, 4-OCH3 2-Cl
3-OCH3, 4-OCH3 4-OCH3
3-OCH3, 4-OCH3 2-OCH3, 4-OCH3
3-OCH3, 4-OCH3 2-OCH3, 3-OCH3
3-OCH3, 4-OCH3 2-Br
4-OCH3
H
4-NH2
2-OH
2-OCH3, 4-OCH3
2-OCH3, 4-OCH3
2-OCH3, 4-OCH3
123

446
Med Chem Res (2012) 21:444–452
Pharmacology
Cytotoxic properties
Table 1 Cytotoxicity of present compounds against three tumor cells
Compound
IC50 (lM)
HT29
SGC7901
It has been reported that chalcones possess a wide-spec-
trum of anti-tumor properties, especially against digestive
cancers. The in vitro cytotoxicity against HT29 (human
colorectal cancer) and SGC7901 (human gastric cancer
cell) were evaluated using the MTT method. Table 1 lists
the IC50 values of present chalcones against two cell lines.
5-Fluorouracil (5-Fu) was used as a positive control. Most
of the chalcones exhibited antiproliferative activities
against selected tumor cells. Arbitrary thresholds of
IC50\30 lM were used to identify promising compounds.
Among tested chalcones, 19 ones were found to have IC50
values that were lower than 30 lM against different cell
lines, and several compounds demonstrated higher cyto-
toxicity than the positive 5-Fu, especially against SGC7901
cells.
1
39.98 1.37
18.87 2.12
42.36 0.83
NA
87.71 23.26
12.58 0.77
ND
2
3
4
N.D.
5
NA
NA
6
29.44 3.02
26.25 1.45
24.19 1.54
55.68 5.6
42.78 2.86
49.06 9.04
59.54 24.36
101.04 23.62
47.82 5.43
18.87 4.55
24.60 2.94
18.56 4.66
130.65 52.38
NA
11.64 2.01
11.15 1.37
7.25 1.87
20.17 3.19
53.76 0.89
19.21 7.4
62.10 16.63
NA
7
8
9
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
5-Fu
7.44 0.88
21.24 0.9
13.74 0.16
14.69 3.17
ND
As an excellent leading compound, chalcones have been
extensively investigated in medicinal chemistry. The sim-
ple structure and the ease of preparation render chalcones
an attractive scaffold for structure–activity relationship
(SAR) studies, and a wide number of substituted chalcones
have been synthesized to evaluate effects of various func-
tional groups on biological activities (Ratkovic et al., 2010;
Hua et al., 2009; Henmi et al., 2009; Tang et al., 2008;
Kamal et al., 2008; Boumendjel et al., 2008; Rao et al.,
2004). Present compounds were designed to evaluate the
SAR on different substitutions (both electron-donating and
electron-withdrawing groups), as well as different positions
on two phenyl rings (A and B).
NA
NA
NA
NA
55.54 0.83
7.87 6.25
NA
ND
ND
53.20 9.12
69.58 34.85
43.74 3.66
41.74 4.13
42.86 0.54
ND
75.41 15.13
61.24 1.36
6.21 0.98
13.08 2.18
40.34 10.55
15.72 12.05
ND
The data given in Table 1 indicate that the change in the
substituent of the phenyl B ring affects the cytotoxic
activity of chalcones. When the B ring is substituted for
strong electron-donating 4-N(CH3)2 or 2,4-dimethoxy
groups, the compounds generally display little bioactivity,
such as 4, 5, 18–21, 35, and 38. The introduction of either
electron-withdrawing or slightly weak electron-donating
substituents (derivatives 1–3, 6–7, 8–13, 14–15, 16–17, 25–
27, 31–34, 36, and 40) enhanced antiproliferative activity.
No significant difference was observed between chalcones
substituted by 2-halogen in ring B. The slightly weak
electron-donating substituents including 4-methoxy and
2,3-dimethoxy in ring B also increased the inhibitory
activity against tumor cells. For example, the anti-
SGC7901 effects of 8 and 26 were highest among all tested
compounds and positive control, with IC50 of 7.25 and
6.21 lM, respectively.
36.43 15.34
35.40 10.32
25.74 5.82
11.13 4.48
18.69 3.23
49.83 8.48
15.45 1.35
54.62 9.75
65.50 4.44
35.86 7.88
13.95 2.38
9.72 1.21
39.61 4.74
19.97 5.26
48.41 7.60
60.5 2.68
NA
24.71 1.78
101.72 19.84
NA
70.67 0.50
21.43 3.53
29.19 4.72
ND not determined; NA no activity
Recently, Boumendjel et al. demonstrated that dimeth-
oxylation or trimethoxylation at 2,4,6-carbons was highly
beneficial to cell cycle arrest at G2/M, while hydroxylation
at 2-position was generally detrimental (Boumendjel et al.,
Several studies have demonstrated the positive influence
of a polymethoxylated ring A on cytotoxicity against tumor
cell lines. For example, Ducki and colleagues reported the
importance of methoxylation on the A-ring (Ducki, 2009).
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Med Chem Res (2012) 21:444–452
447
2008). However, the results from Tzeng group contrasted
with previous results, showing high cytotoxicity of
2-hydroxylated chalcones against Jurkat and U937 cancer
cells (Rao et al., 2004). Thus, a clear correlation between
the substituting pattern of chalcones on the ring A and their
cytotoxicity appears to be difficult to establish. As depicted
in Table 1, all the chalcones with electron-donating sub-
stituents including -NH2, -OCH3 and -OH on the ring A
displayed a strong capacity to inhibit cell proliferation
(compounds 4–5 and 18–21 are still inactive due to elec-
tron-donating-substituted B ring), while the weak activities
were observed on 3,5-difluoride chalcones 13, 21, and 24.
We also analyzed the effects of different position (20, 30, or
40) in ring A where an electron-donating moiety occupied.
Both 2-substituted and 3-substituted chalcones (3 and 10)
with electron-donating groups exhibited cytotoxicity, but
with relatively high IC50 values. Taking together, the
analysis of substituents in ring A showed that the cytotoxic
activity of chalcones could be increased by placing an
electron-donating substituent, especially at 4-position, and
could be reduced through the induction of an electron-
withdrawing substituent. Without the electron-effective
moiety in ring A, the compounds also exhibited excellent
cytotoxic properties. For example, the IC50 values of 8 and
16 (against SGC7901) were all below 15 lM.
anti-bacterial activity studies. All strains were clinically
isolated from local hospitalized patients in the First Affil-
iated Hospital of Wenzhou Medical College and charac-
terized by the Microbial Department in this hospital.
Staphylococcus aureus ATCC 25923 (S. aureus 25923)
purchased from ATCC was used as a non-resistant control.
Details of the 14 strains are described in the reference. The
antibacterial activity of present chalcones was evaluated by
the minimum inhibitory concentration (MIC) method.
Table 2 listed the MIC values of six active chalcones
against seven Grams-positive strains and eight Gram-neg-
ative strains. Other chalcones synthesized in this study
exhibited no activity against these strains. The quinolones
antibiotic levofloxacin served as a positive control. As
expected, some quinolones-resistant strains were not sen-
sitive to levofloxacin. In general, these compounds pos-
sessed higher activity against gram-positive bacteria than
gram-negative bacteria. Among these drug-resistant bac-
teria, Enterococcus faecalis 609230, S. aureus 25923, and
S. aureus 701230 were more sensitive to these compounds.
The 4-(dimethylamino) substituent in ring B of chalcones
may be of importance, for example, 16, 17, 25, and 26
inhibited Gram-positive bacteria growth in a broad spec-
trum. Batovska et al. (2009) reported that 16 had strong
anti-staphylococcal activity with an MIC of 125 lg/ml.
Here, our data further supported earlier result, showing that
16 and 17, especially 17, have strong broad spectrum
antibacterial activity. Thus, the electron-donating substit-
uents at 4-position of ring B may contribute to the anti-
bacterial activity of chalcones. Although the antibacterial
activity of chalcones is not very strong, these stains are all
multidrug-resistant and several are insensitive to levoflox-
acin. Inhibition against them suggests more significant
meanings in clinical therapy. The antibacterial mechanism
of the active chalcones may differ from the current drugs.
Compound 17 showed highest in vitro activity (MIC
\80 lg/ml) and it is currently under further investigation
as a potential anti-bacterial agent.
Digestive cancers are most sensitive to chalcones. Here,
we observed that a majority of compounds exerted high
cytotoxicity against two digestive cancer cell lines HT29
and SGC7901. The underlying molecular mechanism and
the development of new anti-cancer agents from chalcones
are the focus of our continuing research.
Antibacterial activity
A number of bacteria with multiple drug resistance pose a
serious threat to human health. Many clinically efficacious
antibiotics have become less effective due to the devel-
opment of drug resistance (Rodriguez et al., 2010; Lee
et al., 2009). Natural products are a vital source of struc-
turally diverse compounds to spur the development of new
antibacterial agents. Among chalcone derivatives, licoch-
alcone A, naturally isolated from the roots and rhizomes of
Glycyrrhiza inflata, is an active leading compound against
a wide range of Gram-positive organisms (Tsukiyama
et al., 2002). Recently, the antibacterial activity of chal-
cones has been increasingly documented. Many research
groups synthesized novel chalcones that possess antibac-
terial activity (Batovska et al., 2009; Nowakowska et al.,
2008; Liu et al., 2008; Avila et al., 2008; Nielsen et al.,
2005; Rizvi et al., 2010).
The bacterial burden on human health is quickly out-
weighing available therapeutics due to the multidrug
resistance. Combined with a diminishing number of new
agents entering clinical practice, such resistance is widely
recognized as a major threat to public health. Our results
may lead to development of new lead compounds as anti-
bacterial agents against multidrug-resistant clinical strains.
X-ray crystallographic analysis of 16
Finally, compound 16, which displayed duplicate activity,
was re-crystallized from CH3OH/CH2Cl2 (1:2) and its
single-crystal structure were determined by X-ray diffrac-
tion. The structural analysis revealed that two 16 molecules
combined by a hydrogen bonding in one unit cell. All H
One of our long-term goals is to find novel antibiotic
agents that can reverse multidrug resistance. Here, 14
multidrug-resistant bacteria strains were used for these
123

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Med Chem Res (2012) 21:444–452
Table 2 In vitro antibacterial activity of chalcones against bacteria strains
Compound
Minimum inhibitory concentration (MIC, lg/ml) against gram-positive bacteria strains
S.a 25923
S.a 701230
S.a 701219
S.e 620206
S.e 619083
E.f 609230
E.fm 609205
8
279
537
158
40
[1000
537
[1000
[1000
158
[1000
[1000
158
[1000
[1000
158
279
[1000
[1000
315
9
537
16
158
158
17
81
81
81
20
81
[1000
325
25
325
81
325
325
325
325
325
26
161
161
[1000
[1000
81
[1000
[1000
323
Levofloxacin
12.5
12.5
100
125
[1000
Compound
Minimum inhibitory concentration (MIC, lg/ml) against gram-negative bacteria strains
E.c 629119
E.c 629247
K.p 626511
K.p 626238
B-5 302234
B-8 303211
P.a 630266
P.a 701218
8
[1000
158
[1000
158
279
279
[1000
158
[1000
158
279
279
16
[1000
[1000
325
[1000
[1000
325
[1000
[1000
325
158
17
548
548
548
548
[1000
325
25
325
325
325
325
Levofloxacin
[1000
25
125
[1000
[1000
12.5
325
[1000
Information of clinically isolated multidrug-resistant strains: S. a 25923 = Staphylococcus aureus ATCC 25923; S.a 701230 = Staphylococcus
aureus (gentamicin resistant); S.a 701219 = Staphylococcus aureus (penicillin G resistant); S. e 620206 = Staphylococcus epidermidis
(ampicillin, penicillin G, bactrim, erythromycin, gentamicin and oxacillin resistant); S. e 619083 = Staphylococcus epidermidis (bactrim,
clindamycin and amoxicillin resistant); E. f 609230 = Enterococcus faecalis (moxifloxacin, levofloxacin, rifampicin and tetracycline resistant);
E. fm 609205 = Enterococcus faecium (levofloxacin, penicillin G, rifampicin and tetracycline resistant); E. c 629119 = Escherichia Coli
(Ciprofloxacin, Tetracycline, erythromycin, ampicillin, gentamicinampicillin and gentamicin resistant); E. c 629247 = Escherichia Coli
(ampicillin, aztreonam, ceftriaxone, cefepime, bactrim, sulbactam, cefazolin and ceftazidime resistant); K. p 626511 = klebsiella pneumonia
(ampicillin resistant); K. p 626238 = Klebsiella pneumonia (ampicillin, ciprofloxacin, nitrofurantoin and levofloxacin resistant); B5
302234 = baumanii (ampicillin, sulbactam, aztreonam, ciprofloxacin, ceftriaxone, cefazolin, nitrofurantoin, cefepime, gentamicin, tienam,
levofloxacin, bactrim, ceftazidime, Tobramycin, Piperacillin, Rifampicin and Tetracycline resistant); B8 303211 = baumanii (ampicillin,
nitrofurantoin and cefazolin resistant); P. a 630266 = Pseudomonas aeruginosa (ampicillin, sulbactam, ceftriaxone, cefazolin, nitrofurantoin and
bactrim resistant); P. a 701218 = Pseudomonas aeruginosa (ampicillin, sulbactam, ceftriaxone, cefazolin, nitrofurantoin, bactrim, tienam,
ciprofloxacin and levofloxacin resistant))
atoms were located in different Fourier maps and were
˚
refined freely in idealized positions, with C–H = 0.93 A
˚
for aromatic H and vinyl H or 0.96 A for methylene H. The
isolated multidrug-resistant strains. Our structural design
altered bioactivity profile of the chalcones and indicated a
combination of SAR analysis toward the substituents in
rings A and B of chalcones. The electron-donating modi-
fication in ring A may be pharmacologically favorable for
chalcones-based anti-tumor drug development. Our data
crystal structure of the unit cell of 16 is shown in Fig. 1.
The details of the crystal data, data collection, and refine-
ment are listed in Table 3. The geometry lengths of the
intermolecular hydrogen bond are given in Table 4. The
results showed that the crystal of 16 belongs to the ortho-
rhombic system, space group P2(1)2(1)2(1) with
also yielded
a few novel leading compounds for
the development of potential antibacterial candidates with
the ability of reversal of multidrug resistance. In addition,
the crystal structure of compound 16 with strong cytotox-
icity and anti-bacterial activities was reported.
˚
a = 5.3796 (6) A, b = 12.9543 (14) A, c = 17.1522 (18)
˚
3
˚
˚
A, a = b = c = 90°, V = 1195.2 (2) A , Z = 4,
F000 = 472, Dx = 1.246 Mg m-3, and l = 0.08 mm-1. A
dihedral angle between the two phenyl rings C4/C5/C6/C7/
C8/C9 and C10/C11/C12/C13/C14/C15 is 25.39°.
Experimental section
General procedure for the synthesis of chalcones
Conclusion
1H-NMR spectra were recorded on a Bruker AVANCE
600 MHz spectrometer. Electron-spray ionization mass
spectra in positive mode (ESI–MS) data were recorded on
Bruker Esquire HCT ion-trap mass spectrometer equipped
In summary, a series of chalcones were synthesized as
potent cytotoxic agents against two human digestive tumor
cell lines and antimicrobial agents against 14 clinically
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Med Chem Res (2012) 21:444–452
449
Fig. 1 The crystal structure of
16 in a unit cell with labeled
non-hydrogen atom, showing
displacement ellipsoids at the
50% probability level. Dashed
lines indicate intramolecular
hydrogen bonding
Table 3 Crystal data of 16
Crystal data
C15H12O2
˚
a = b = c = 90°
Cell parameters from 1584 reflections
k = 0.71073 A
FW = 224.25
3
˚
V = 1195.2 (2) A
Orthorhombic, P2(1)2(1)2(1)
Prismatic, green Z = 4
h = 4.8–45.2°
l = 0.08 mm-1
T = 293 (2) K
˚
a = 5.3796 (6) A
F000 = 472
Dx = 1.246 Mg m-3
˚
b = 12.9543 (14) A
˚
c = 17.1522 (18) A
Mo Ka radiation
0.40 9 0.38 9 0.27 mm
Data collection
Tmin = 0.592
Tmix = 1.000
hmax = 26.0°
Refinement
6525 independent reflections,
1167 reflections with I [ 2r (I)
hmin = 2.0°
h = -6 ? 6; k = -15 ? 15; l = -21 ? 9
Rint = 0.056
R[F2 [ 2r(F2)] = 0.039 1396 reflections
(D/r)max \ 0.001
-3
wR(F2) = 0.095
159 parameters
w = 1/[r2(F2o) ? (0.0537P)2]
Dqmax = 0.09 e A
˚
-3
˚
S = 1.04
Dqmin = -0.14 e A
Table 4 Hydrogen-bond geometry for compound 16
added dropwise. The mixture was stirred at room temper-
ature for 4–8 h. The resulting precipitate was filtered and
washed with water and cold ethanol, and then dried in
vacuum. For 3, 12 and 16: To a solution of 10 mmol
acetophenones in dried EtOH (10 ml) was added 10 mmol
aryl aldehydes. The mixture was heated until a clear
solution was obtained. Then a dried HCl gas producted by
the reaction of H2SO4 and NaCl was inleted to the solution
until saturated. The mixture was stirred and refluxed for
24 h. The resulting precipitate was filtered and washed
with water and cold ethanol, and then dried in vacuum.
Compounds 7, 11, 15–17, 28, 29, 31, 32 were purified
by recrystallization using alcohol and CH2Cl2 (1:2–2:1).
Other compounds were purified by silica gel column
˚
D–H (A)
˚
˚
D–HꢀꢀꢀA
HꢀꢀꢀA (A)
1.84 (3)
DꢀꢀꢀA (A)
2.691 (2)
D–HꢀꢀꢀA (°)
175 (3)
O2–H2AꢀꢀꢀO1i
Symmetry codes: (i) -x?3/2, -y?2, z - 1/2
0.85 (3)
with an electrospray ion source. Melting points were
determined on a Fisher-Johns melting apparatus and are
corrected. Column chromatography purifications were
carried out on Silica Gel 60 (E. Merck, 70-230 mesh).
General procedure for synthesis of chalcones: To a
solution of 10 mmol acetophenone in EtOH (10 ml) was
added 10 mmol aryl aldehydes. The solution was stirred at
5–10°C, and 40%(w/v) NaOH in H2O (10 mmol) was
123

450
Med Chem Res (2012) 21:444–452
chromatography using CH2Cl2/CH3OH as the eluent. The
structural data in 1HNMR and ESI–MS of newly described
compounds were listed as following.
J = 7.8 Hz, 1H, H-6), 7.750 (t, 1H, H-5), 7.635 (t, 1H,
H-4), 6.760 (d, J = 8.4 Hz, 2H, H-30, H-50). ESI–MS m/z:
292.5(M ? 1)?, calcd for C16H12F3NO: 291.27.
4.1.1 (E)-2,4-dichloro-40-aminochalcone (1): orange
4.1.7 (E)-2-bromo-40-aminochalcone (31): yellow
1
1
yellow power, 22.1% yield, mp 189.0–190.5°C. H-NMR
power, 38% yield, mp 143.2–147.9°C. H-NMR (CDCl3),
(DMSO), d: 8.215 (d, J = 8.4 Hz, 2H, H-20, H-60), 7.947
(d, J = 15.6 Hz, 1H, H-b), 7.935 (d, J = 8.4 Hz, 1H, H-6),
7.854 (d, J = 15.6 Hz, 1H, H-a), 7.727 (s, 1H, H-3), 7.520
(d, J = 8.7 Hz, 1H, H-5), 6.621 (d, J = 8.4 Hz, 2H, H-30,
H-50), 4.180 (brs, 2H, NH2-40). ESI–MS m/z: 290.3(M-1)-,
calcd for C15H11Cl2NO: 292.16.
d: 8.083(d, J = 15.6 Hz, 1H, H-b), 7.930 (d, J = 8.4 Hz,
2H, H-20, H-60), 7.719 (d, J = 7.8 Hz, 1H, H-3), 7.630 (d,
J = 7.8 Hz, 1H, H-6), 7.432 (d, J = 15.6 Hz, 1H, H-a),
7.347 (t, 1H, H-5), 7.229 (t, 1H, H-4), 6.705(d, J = 8.4 Hz,
2H, H-30, H-50), 4.150 (brs, 2H, NH2-40). ESI–MS m/z:
302.0 (M ? 1)?, calcd for C15H12BrNO: 302.17.
4.1.2 (E)-4-dimethylamino-30,50-difluorochalcone (5):
orange yellow power, 5.43% yield, mp 125.0–129.7°C. 1H-
NMR (CDCl3), d: 7.821 (d, J = 15.6 Hz, 1H, H-b), 7.552
(d, J = 9.0 Hz, 2H, H-2, H-6), 7.500 (dd, J = 1.8 Hz,
7.8 Hz, 2H, H-20, H-60), 7.200 (d, J = 15.0 Hz, 1H, H-a),
6.987 (tt, J = 2.4 Hz, 8.4 Hz, 1H, H-40), 6.697 (d,
J = 9.0 Hz, 2H, H-3, H-5), 3.062 (s, 6H, OCH3-30, OCH3-
40). ESI–MS m/z: 288.3(M ? 1)?, calcd for C17H15F2NO:
287.3.
4.1.8 (E)-2,6-difluoro-40-methoxychalcone (33): white
1
power colorless crystal, 55% yield, mp 88.4–90.5°C. H-
NMR (CDCl3), d: 8.037 (d, J = 8.4 Hz, 2H, H-20, H-60),
7.823 (d, J = 15.6 Hz, 1H, H-b), 7.618 (d, J = 16.2 Hz,
1H, H-a), 7.322–7.3369 (m, 1H, H-4), 7.061–7.088 (m, 2H,
H-3, H-5), 6.992 (d, J = 8.4 Hz, H-30, H-50), 43.900 (s,
3H, -OCH3-40).IR (cm-1): 1655 (C = O), 1491, 1572,
1598 (Ar), 1600 (C = C), 3410 (NH2), 1187 (C–O).. ESI–
MS m/z: 274.1(M ? 1)?, calcd for C16H12F2O2: 274.26.
4.1.9 (E)-2-chloro -30,40-dimethoxychalcone (36):
white power, 93.7% yield, mp 70.2–72.8°C. 1H-NMR
(CDCl3), d: 8.186 (d, J = 15.6 Hz, 1H, H-b), 7.770 (d,
J = 7.8 Hz, 1H, H-60), 7.704 (d, J = 8.4 Hz, 1H, H-6),
7.651 (s, 1H, H-20), 7.522 (d, J = 15.6 Hz, 1H, H-a), 7.475
(d, J = 7.8 Hz, 1H, H-3), 7.345–7.358 (m, 2H, H-4, H-5),
6.964 (d, J = 8.4 Hz, 1H, H-50), 3.985 (s, 6H, OCH3-30,
OCH3-40). ESI–MS m/z: 303.6(M ? 1)?, 305.6(M ? 1)?,
calcd for C17H15ClO3: 302.75.
4.1.3 (E)-4-methoxy-30,50-difluorochalcone (13): light
1
yellow power, 67.7% yield, mp 101.2–102.1°C. H-NMR
(CDCl3), d: 7.820 (d, J = 15.6 Hz, 1H, H-b), 7.615 (dd,
J = 1.8 Hz, 8.4 Hz, 2H, H-2, H-6), 7.511 (m, J = 2.4 Hz,
7.8 Hz, 2H, H-20, H-60), 7.285 (d, J = 15.6 Hz, 1H, H-a),
7.019 (tt, J = 1.8 Hz, 1H, H-4), 6.951 (dd, J = 1.8 Hz,
8.4 Hz, 2H, H-3, H-5), 3.869 (s, 3H, OCH3-4). ESI–MS
m/z: 275.1(M ? 1)?, calcd for C16H12F2O2: 274.26.
4.1.4 (E)-2-fluoro-40-aminochalcone (14): yellow
power, 91.6% yield, mp 138.7–140.4°C. 1H-NMR
(CDCl3), d: 7.936 (d, J = 7.8 Hz, 2H, H-20 H-60), 7.863 (d,
J = 15.6 Hz, 1H, H-b), 7.653 (d, J = 15.6 Hz, 1H, H- a),
7.619–7.647 (m, 1H, H-6), 7.345–7.362 (m, 1H, H-4),
7.170–7.196 (m, 1H, H-5), 7.105–7.138 (m, 1H, H-3),
6.704 (d, J = 7.8 Hz, 2H, H-30, H-50), 4.185 (brs, 2H,
NH2-40). ESI–MS m/z: 240.2(M-1)-, calcd for
C15H12FNO: 241.26.
4.1.10 (E)-2,3-dimethoxy -30,40-dimethoxychalcone
(39): white power, 69.1% yield, mp 82.5–84.2°C. 1H-NMR
(CDCl3), d: 8.072 (d, J = 15.6 Hz, 1H, H-b), 7.782 (dd,
J = 1.8 Hz, 8.4 Hz, 1H, H-60), 7.628 (d, J = 15.6 Hz, 1H,
H-a), 7.629 (d, J = 1.8 Hz, 1H, H-20), 7.275 (dd,
J = 1.2 Hz, 7.8 Hz, 1H, H-6), 7.098 (t, J = 8.4 Hz, 1H,
H-5), 6.967 (dd, J = 1.2 Hz, 7.8 Hz, 1H, H-4), 6.932 (d,
J = 8.4 Hz, 1H, H-50), 3.973 (s, 3H, OCH3-2), 3.970 (s,
3H, OCH3-30), 3.897 (s, 3H, OCH3-3), 3.890 (s, 3H, OCH3-
40). ESI–MS m/z: 329.0(M ? 1)?, calcd for C19H20O5:
328.36.
4.1.11 (E)-2-bromo-30,40-dimethoxychalcone (40):
white power, 75.3% yield, mp 99.2–103.5°C. 1H-NMR
(CDCl3), d: 8.107 (d, J = 15.6 Hz, 1H, H-b), 7.230 (dd,
J = 1.2 Hz, 7.8 Hz, 1H, H-3), 7.675 (dd, J = 1.8 Hz,
8.4 Hz, 1H, H-30), 7.642 (dd, J = 1.2 Hz, 8.4 Hz, 1H,
H-6), 7.622 (d, J = 1.8 Hz, 1H, H-20), 7.432 (d,
J = 15.6 Hz, 1H, H-a), 7.364 (t, J = 7.8 Hz, 1H, H-5),
7.243 (dd, J = 1.2 Hz, 7.2 Hz, 1H, H-4), 6.935 (d,
J = 8.4 Hz, 1H, H-50), 3.974 (s, 6H, OCH3-30, OCH3-40).
ESI–MS m/z: 349.6(M ? 1)?, 347.7(M ? 1)?, calcd for
C17H15BrO3: 347.2.
4.1.5 (E)-2,4-dimethoxy-30,50-difluorochalcone (21):
1
yellow power, 69.4% yield, mp 144.4–149.3°C. H-NMR
(CDCl3), d: 8.069 (d, J = 16.2 Hz, 1H, H-b), 7.564 (d,
J = 8.4 Hz, 1H, H-6), 7.500 (dd, J = 1.8 Hz, 7.2 Hz, 2H,
H-20, H-60), 7.429 (d, J = 15.6, 1H, H-a), 6.997 (tt,
J = 1.8 Hz, 8.4 Hz, 1H, H-40), 6.547 (dd, J = 1.8 Hz,
8.4 Hz, 1H, H-5), 6.483 (d, J = 1.8 Hz, 1H, H-3), 3.916 (d,
3H, OCH3-2), 3.867 (d, 3H, OCH3-4). ESI–MS m/z:
305.3(M ? 1)?, calcd forC17H14F2O3: 304.29.
4.1.6 (E)-2-trifluoromethyl-40-aminochalcone (29):
1
yellow crystal, 71.7% yield, mp 179.8–181.3°C. H-NMR
(CDCl3), d: 8.196 (d, J = 7.8 Hz, 1H, H-3), 8.067 (d,
J = 15.6 Hz, 1H, H-b), 7.988 (d, J = 8.4 Hz, 2H, H-20,
H-60), 7.867(d, J = 15.6 Hz, 1H, H-a), 7.819(d,
123

Med Chem Res (2012) 21:444–452
451
Methyl thiazolyl tetrazolium (MTT) assay
ESI–MS analysis are described in Online Supplemental
Data. Supplementary crystallographic data for 16 (CCDC
No. 717888) can be obtained free of charge at CCDC
database.
Cells were cultured in RMPI-1640 containing 10% FBS
and seeded in 96-well plates with 5000 cells per well. After
incubated in a CO2 incubator for 24 h, compounds in
DMSO at the concentrations of 100 lM, 33 lM, 11 lM
and 3.7 lM and vehicle control were added to each plate,
respectively. After 72 h treatment, a fresh solution of MTT
(5 mg/ml) prepared in NaCl solution (0.9%) was added to
each single well of the 96-well plate. The plate were then
incubated for 3 h, cells dissolved with 100 ll DMSO, and
then analyzed in a multi-well-plate reader at 570 nM. Each
compound was tested at least three runs for each concen-
tration. IC50 values were determined using Prism GraphPad
software.
Acknowledgments This study was partially supported by the
National Natural Science Funding of China (20802054), Young
Talent Funding of Zhejiang Department of Health (2009QN020), Key
Project of Wenzhou Sci & Tech Bureau (Y20090009 & Y20100006),
and Zhejiang Natural Science Funding (Y2101108 & Y4090261).
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