Novel antileishmanial chalconoids: Synthesis and biological activity of 1- or 3-(6-chloro-2H-chromen-3-yl)propen-1-ones

Article abstract of DOI:10.1016/j.ejmech.2009.12.046

A series of novel chalconoids containing a 6-chloro-2H-chromen-3-yl group were prepared through a convenient and efficient synthetic method by using 5-chloro-2-hydroxybenzaldehyde as starting material. The target compounds were evaluated against the promastigote form of Leishmania major using MTT assay. All of the evaluated compounds have shown high in vitro antileishmanial activity at concentrations less than 3.0 μM. The results of cytotoxicity assessment against mouse peritoneal macrophage cells showed that these compounds display antileishmanial activity at non-cytotoxic concentrations.

Full text of DOI:10.1016/j.ejmech.2009.12.046

European Journal of Medicinal Chemistry 45 (2010) 1424–1429
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Novel antileishmanial chalconoids: Synthesis and biological activity
of 1- or 3-(6-chloro-2H-chromen-3-yl)propen-1-ones
Zohreh Nazarian a, Saeed Emami b, Samaneh Heydari c, Sussan K. Ardestani d, Maryam Nakhjiri a,
,c,
Fatemeh Poorrajab d, Abbas Shafiee a, Alireza Foroumadi a
*
a Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14174, Iran
b Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
c Drug Design & Development Research Center, Tehran University of Medical Sciences, Tehran 14174, Iran
d Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1365, Tehran, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel chalconoids containing a 6-chloro-2H-chromen-3-yl group were prepared through
a convenient and efficient synthetic method by using 5-chloro-2-hydroxybenzaldehyde as starting
material. The target compounds were evaluated against the promastigote form of Leishmania major using
MTT assay. All of the evaluated compounds have shown high in vitro antileishmanial activity at
Received 6 August 2009
Received in revised form
8 December 2009
Accepted 18 December 2009
Available online 28 December 2009
concentrations less than 3.0
mM. The results of cytotoxicity assessment against mouse peritoneal
macrophage cells showed that these compounds display antileishmanial activity at non-cytotoxic
concentrations.
Keywords:
Ó 2009 Elsevier Masson SAS. All rights reserved.
Chromene
Chalcones
Leishmania major
Antileishmanial activity
1. Introduction
(GlucantimeÒ), pentamidine, amphotericin B and miltefosine [4].
Despite the recent advances in new antileishmanial agents, the
Leishmaniasis is a parasitic infection caused by different species
belonging to the genus Leishmania, a protozoan which is trans-
mitted to humans by the bite of female phlebotomine sandfly.
Leishmaniasis infection causes a wide spectrum of disease in
humans, with many different clinical manifestations, such as
cutaneous, mucocutaneous and visceral leishmaniasis, which can
be fatal when untreated. Leishmaniasis has a major and increasing
impact on global public health and is endemic in many tropical and
subtropical regions of the world, particularly in Africa, Asia, and
Latin America. It found in 88 countries and affects around 12
million people of the world and 350 million people are at risk of
infection with Leishmania spp [1,2].
first-line therapy to all forms of leishmaniasis still requires
multiple, potentially toxic and painful injections with pentavalent
antimonials [5]. Furthermore, clinical resistance to pentavalent
antimonials has been reported recently. This resistance occurred
in 5–70% of patients in some areas of endemicity [6]. The
chemotherapy with the second-line drug pentamidine is also far
from satisfactory due to several side effects including renal and
hepatic toxicity, pancreatitis, hypotension, dysglycemia, and
cardiac abnormalities [7]. Although amphotericin B and its lipid
complex, are quite effective for visceral leishmaniasis, they are
expensive and do not appear to be suitable for treatment of non-
visceral diseases [7].
The management of leishmaniasis relies entirely on chemo-
therapy and so far no vaccine approved for human use is available
[3]. The drugs available for the treatment of Leishmania infections
is limited and includes pentavalent antimonials such as
sodium stibogluconate (PentostamÒ) and meglumine antimonate
Newly introduced oral miltefosine, a phosphocholine analogue,
has shown promise in the treatment of visceral leishmaniasis [8],
but presenting severe gastrointestinal problems and teratogenic
effects [9,10]. It is also known that current drugs contribute to
increased Leishmania–HIV co-infections. No treatment has proven
to be effective in achieving radical cure of visceral leishmaniasis
when it is associated with HIV infection. Therefore, there is an
increasingly urgent need for the development of new, orally active,
inexpensive, effective and safe drugs for the treatment of
leishmaniasis.
* Corresponding author. Faculty of Pharmacy and Pharmaceutical Sciences
Research Center, Tehran University of Medical Sciences, Tehran 14174, Iran. Tel.:
þ98 21 66954708; fax: þ98 21 66461178.
E-mail address: aforoumadi@yahoo.com (A. Foroumadi).
0223-5234/$ – see front matter Ó 2009 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2009.12.046

Z. Nazarian et al. / European Journal of Medicinal Chemistry 45 (2010) 1424–1429
1425
O
B
A
Chalcone; general structure
OH
O
O
R
O
H3CO
1, L i c o c h a l c o n e
HO
OH
2
A
2a:Crotaramosmin: R = 4-OH
2b: Crotaramin: R=4-OCH
3
2c: Crotin:3,4-(OH) 2
O
O
Cl
Cl
R
R
O
O
3a-d
4a-d
Fig. 1. Structure of chalcone, chalcone-like compounds 1 and 2 with antileishmanial activity, and designed chalconoids 3 and 4 as potential antileishmanial agents.
In the search for finding new antileishmanial drugs, both
synthetic and natural origin compounds comprising a diverse
group of chemical structures have been reported, including chal-
cones present in Glycirrhyza glabra and Piper aduncum [11,12]. Also,
the antileishmanial activity of several chalcones have been repor-
ted in the literature [13–16]. The most promising member of this
group is licochalcone A (1, Fig. 1), an oxygenated chalcone isolated
from the roots of Chinese liquorice [15]. A number of chalcone-like
2. Results and discussion
2.1. Chemistry
The general synthetic pathway used to synthesize the desig-
nated compounds 3 and 4 is outlined in Scheme 1. The treatment of
5-chloro-2-hydroxybenzaldehyde
dioxane in the presence of potassium carbonate afforded desired
chromene-3-carbaldehyde 6. Claisen–Schmidt condensation of
compound 6 with various acetophenones in ethanolic solution of
5 with acrolein in refluxing
compounds
having
5-hydroxy-2H-chromen-6-yl
moieties
(compounds 2) are reported to be potential agents against Leish-
mania in biological assays [17,18]. Based on these observations and
our program for designing new antileishmanial agents [19–23] we
hypothesized to synthesize 1- or 3-(6-chloro-2H-chromen-
3-yl)propen-1-ones (3 and 4) in which ring A or ring B of typical
chalcones was replaced by 6-chloro-2H-chromen-3-yl moiety
(Fig. 1). Thus, we herein report the synthesis and in vitro anti-
leishmanial activity of 1- or 3-(6-chloro-2H-chromen-3-yl)propen-
1-ones.
NaOH
afforded
3-(6-chloro-2H-chromen-3-yl)propen-1-ones
3a–d. The second type of target compounds as typified by general
structure 4a–d (Fig. 1), were prepared by a distinct rout (Scheme 1).
First, 5-chloro-2-hydroxybenzaldehyde 5 was reacted with methyl
vinyl ketone in refluxing dioxane in the presence of potassium
carbonate to give 1-(6-chloro-2H-chromen-3-yl)ethanone 7. Then,
Claisen–Schmidt condensation of compound 7 with different
aldehydes in ethanolic solution of NaOH yielded corresponding
O
O
Cl
Cl
H
b
R
O
O
6
3a-d
a
Cl
CHO
OH
c
5
O
O
Cl
Cl
d
CH3
R
O
7
O
4a-d
Scheme 1. Synthesis of chalconoids 3a–d and 4a–d. Reagents and conditions: (a) acrolein, 1,4-dioxane, K2CO3, reflux (b) appropriate acetophenone, NaOH, EtOH (c) methyl vinyl
ketone, 1,4-dioxane, K2CO3, reflux (d) appropriate aldehyde, NaOH, EtOH.

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Z. Nazarian et al. / European Journal of Medicinal Chemistry 45 (2010) 1424–1429
1-(6-chloro-2H-chromen-3-yl)propen-1-ones 4a–d. Yields for final
step ranged from 13% to quantitative but were not optimized. The
chalcones 3 and 4 were always obtained as (E)-isomer as judged by
1H NMR spectroscopy. Examination of the 1H NMR coupling
2.2. Biology
The parasitic protozoan Leishmania is digenetic and has two
distinct stages in its life cycle. The motile flagellated promastigote
stage lives in the alimentary canal of the sandfly vector, which, by
inoculation, transmits the promastigotes into the mammalian host,
where they enter macrophages differentiating and multiplying into
non-motile amastigotes [24]. In our study, the target compounds
constants of
a and b-vinylic protons in compounds 3 and 4 clearly
showed a large Ja values (15.5–16.0 Hz) and suggests a trans-
,
b
configuration. The structures and physicochemical data of final
compounds are illustrated in Table 1.
Table 1
Structures and physicochemical data of chalconoids 3a–d and 4a–d.
O
Ring B
Ring A
Compound
Ring A
Ring B
m.p. (ꢀC)
184–185
M.W
Yield (%)
89
Formula
Cl
Cl
Cl
3a
314.74
C18H12ClFO2
F
O
O
O
3b
3c
191–192
331.19
365.64
45
88
C18H12Cl2O2
Cl
226
C18H11Cl3O2
Cl
Cl
OCH3
OCH3
Cl
3d
207
386.83
13
C21H19ClO5
O
OCH3
Cl
Cl
Cl
Cl
4a
4b
167
147
375.64
310.77
98
49
C18H12BrClO2
Br
O
C19H15ClO2
H3C
O
O
O
H3CO
4c
146
167
356.80
356.80
46
18
C20H17ClO4
OCH3
4d
C20H17ClO4
OCH3
OCH3

Z. Nazarian et al. / European Journal of Medicinal Chemistry 45 (2010) 1424–1429
1427
Table 2
third day of incubation, were calculated based on a linear regres-
sion. All data were reported as the mean ꢁ SD in Table 2.
In vitro activities of compounds 3a–d and 4a–d against promastigote form of
L. major.
Generally, the IC50 values of the test compounds 3a–d and 4a–d
indicate that all compounds exhibit high activity against L. major
O
(IC50 ꢂ 3.0
mM). Structurally, compounds 3a–d have a group
6-chloro-2H-chromen-3-yl at the 3-position of propenone linkage
(ring A), whereas compound 4a–d have this pendant group at the
position 1 of propenone (ring B). Obtained results based on the IC50
values of compounds 3a–d and 4a–d demonstrated that these
restricted series of compounds showed small differences in their
overall activity profile. It seems that in (6-chloro-2H-chromen-
3-yl)propenones, the biological activity against L. major was slightly
influenced by the type of secondary aryl ring attached to the 1- or
3-position of propenone linker. Thus, the structure–activity rela-
tionship study was not crucial. However, it is notable that
compounds 3b and 4a (containing 2-chlorophenyl and 2-bromo-
phenyl, respectively) with IC50 values of 1.22 ꢁ 0.31 and 1.33 ꢁ 0.52
Ring B
Ring A
Compound
Ring A
Ring B
IC50 (m
M)a
Cl
Cl
Cl
3a
2.22 ꢁ 0.60
1.22 ꢁ 0.31
1.91 ꢁ 0.35
F
O
O
O
mM proved to be statistically the most potent compounds.
Comparison of the IC50 values reveals that certain substituents such
as methyl, dimethoxy and trimethoxy on phenyl are permitted and
well tolerated but cannot improve the inhibitory activity respect to
halogen substituents against Leishmania promastigotes.
The in vitro toxicity of compounds 3a–d and 4a–d against
mouse peritoneal macrophages was also assessed using MTT
colorimetric assay. Macrophage cells were treated with synthesized
compounds at the concentrations equal to IC50 values (against L.
major) for 24 h, side by side with the reference drug GlucantimeÒ.
Whereas, the reference drug decreased viability of macrophages up
to 40%, the test compound showed no effect on viability of
macrophage cells at those levels of concentrations.
3b
3c
Cl
Cl
Cl
OCH3
OCH3
Cl
3d
2.06 ꢁ 0.22
In conclusion,
a series of novel chalconoids containing
O
a 6-chloro-2H-chromen-3-yl group were prepared through an easy,
convenient, and efficient synthetic method by using 5-chloro-
2-hydroxybenzaldehyde as starting material. This new class of
chalconoids has been identified as potential antileishmanial agents.
All of the evaluated compounds have shown high in vitro anti-
OCH3
Cl
Cl
Cl
4a
4b
4c
1.33 ꢁ 0.52
2.75 ꢁ 0.37
3.00 ꢁ 0.60
leishmanial activity at concentrations less than 3.0 mM. The results
Br
O
O
O
of cytotoxicity assessment showed that these compounds display
antileishmanial activity at non-cytotoxic concentrations. Thus,
(6-chloro-2H-chromen-3-yl)propenone can be considered as
a promising lead for the development of an effective agent for
chemotherapy of leishmaniasis and other protozoan infections.
H3C
3. Experimental
H3CO
All chemicals and solvents used in this study were purchased
from Merck chemical. Melting points were determined on a kofler
hot stage apparatus and are uncorrected. The IR spectra were
OCH3
obtained on
a Shimadzu 470 spectrophotometer (potassium
bromide disks). 1H NMR spectra was recorded using a Bruker 500
spectrometer and chemical shifts are reported in parts per million
(ppm) relative to TMS as internal standard. The mass spectra were
run on a Finigan TSQ-70 spectrometer (Finigan, USA) at 70 eV.
Elemental analyses were carried out on CHN–O rapid elemental
analyzer (GmbH–Germany) for C, H and N, and the results are
within ꢁ0.4% of the theoretical values. Merck silica gel F254 plates
were used for analytical TLC.
Cl
OCH3
OCH3
4d
2.80 ꢁ 0.27
30 ꢁ 0.189b
O
GlucantimeÒ
a
The values represent mean ꢁ SD.
b
3.1. Synthesis of 6-chloro-2H-chromene-3-carbaldehyde (6)
The IC50 of Glucantime was in mg/mL.
A mixture of 5-chloro-2-hydroxybenzaldehyde (7 mmol) and
potassium carbonate (7 mmol) in 1,4-dioxane (12.5 mL) was treated
with acrolein (0.5 mL). The mixture was heated at 100 ꢀC for 8 h and
allowed to cool. The mixture was diluted with water and extracted
several times with ether. The combined ether extracts were dried
were subjected to in vitro antileishmanial activity profile against
the promastigote form of the Leishmania major using MTT assay,
side by side the reference drug GlucantimeÒ. The inhibitory
concentrations for 50% of inhibition (IC50) of Leishmania growth, at

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Z. Nazarian et al. / European Journal of Medicinal Chemistry 45 (2010) 1424–1429
(Na2SO4) and evaporated to give compound 6 as a yellow solid
which was crystallized from ethyl acetate–hexane. Yield 78%; m.p.
91–93 ꢀC [25].
(12), 192 (64), 175 (50), 145 (29), 127 (50), 110 (37), 100 (34), 82 (41),
70 (100), 44 (35). Anal. Calcd for C18H11Cl3O2: C, 59.13; H, 3.03.
Found: C, 58.88; H, 2.97.
3.2. Synthesis of 1-(6-chloro-2H-chromen-3-yl)ethanone (7)
3.3.4. (E)-3-(6-Chloro-2H-chromen-3-yl)-1-(3,4,5-
trimethoxyphenyl)prop-2-en-1-one (3d)
A mixture of 5-chloro-2-hydroxybenzaldehyde (5 mmol) and
potassium carbonate (5 mmol) in 1,4-dioxane (5 mL) was treated
with methyl vinyl ketone (5 mmol). The mixture was heated at 100
ꢀC for 4 h and allowed to cool. The mixture was diluted with water
and extracted several times with ether. The combined ether
extracts were dried (Na2SO4) and evaporated to give compound 7
as a yellow solid, which was crystallized from ethyl acetate–hexane
Yield 82%; m.p. 50–51 ꢀC [25].
1H NMR (500 MHz, CDCl3)
d
: 7.51 (d, 1H, J ¼ 16 Hz, H3 prope-
none), 7.21 (s, 2H, H2 and H6 phenyl), 7.15 (dd,1H, J ¼ 8.5 and 2.5 Hz,
H7 chromene), 7.09 (d, 1H, J ¼ 2.5 Hz, H5 chromene), 6.82 (d, 1H, J ¼
8.5 Hz, H8 chromene), 6.81–6.78 (m, 2H, H4 chromene and H2
propenone), 5.10 (s, 2H, OCH2), 3.95 (s, 9H, OCH3). 13C NMR (125
MHz, CDCl3): 188.6, 153.2, 152.9, 142.7, 140.9, 133.2, 130.7, 130.4,
129.9, 127.3, 126.6, 123.2, 121.1, 117.1, 106.1, 65.4, 61.0, 56.4. IR (KBr,
cmꢃ1
)
nmax: 1741 (C]O). MS (m/z, %): 388 (Mþ2, 40), 386 (Mþ, 100),
371 (18), 312 (10), 220 (21), 191 (43), 167 (24), 154 (32), 127 (11).
Anal. Calcd for C21H19ClO5: C, 65.20; H, 4.95. Found: C, 65.20; H, 5.07.
3.3. General procedure for the synthesis of 3-(6-chloro-2H-
chromen-3-yl)-1-phenyl propen-1-one derivatives 3a–d
3.4. General procedure for the synthesis of 1-(6-chloro-2H-
To a well stirred solution of compound 6 (1 mmol) and
substituted acetophenone (1 mmol) in absolute ethanol (5 mL), was
added a 3.5 M NaOH solution (2 mL) and stirred overnight in an ice-
bath. The reaction mixture was diluted with water and the
precipitate was filtered and crystallized from ethanol to give cor-
responding chalconoids 3a–d.
chromen-3-yl)-3-phenyl propen-1-one derivatives 4a–d
To a well stirred solution of 1-(6-chloro-2H-chromen-3-yl)-
ethanone (7, 1 mmol) and appropriate aldehyde (1 mmol) in
absolute ethanol (5 mL), was added a 3.5 M NaOH solution (2 mL)
and stirred overnight in an ice-bath. The reaction mixture was
diluted with water and the precipitate was filtered and crystallized
from ethanol to give corresponding chalconoids 4a–d.
3.3.1. (E)-3-(6-Chloro-2H-chromen-3-yl)-1-(2-fluorophenyl)-
prop-2-en-1-one (3a)
1H NMR (500 MHz, CDCl3)
d: 7.81 (dd, 1H, J ¼ 7.5 and 1.5 Hz, H6
3.4.1. (E)-3-(2-Bromophenyl)-1-(6-chloro-2H-chromen-3-yl)-
prop-2-en-1-one (4a)
phenyl), 7.57–7.52 (m, 1H, H4 phenyl), 7.50–7.45 (m, 1H, H5 phenyl),
7.40 (dt, 1H, J ¼ 7.5 and 1.5 Hz, H3 phenyl), 7.20–7.17 (m, 1H, H3
propenone), 7.15 (dd, 1H, J ¼ 8.5 and 2.5 Hz, H7 chromene), 7.13 (d,
1H, J ¼ 2.5 Hz, H5 chromene), 6.79 (d, 1H, J ¼ 8.5 Hz, H8 chromene),
6.78–6.73 (m, 2H, H2 propenone and H4 chromene), 5.06 (s, 2H,
OCH2). 13C NMR (125 MHz, CDCl3): 188.8, 162.2, 160.2, 153.1, 146.6,
140.8, 134.1, 131.0, 130.5, 130.0, 127.3, 125.0, 124.6, 123.1, 119.4, 117.2,
1H NMR (500 MHz, CDCl3)
d
: 7.79 (t, 1H, J ¼ 1 Hz, H4 chromene),
7.65 (d, 1H, J ¼ 15.5 Hz, H3 propenone), 7.57–7.53 (m, 2H, H3 and H6
phenyl), 7.39 (m, 1H, H5 phenyl), 7.34 (d, 1H, J ¼ 15.5 Hz, H2 pro-
penone), 7.32–7.29 (m, 1H, H4 phenyl), 7.23 (d, 1H, J ¼ 2.5 Hz, H5
chromene), 7.22–7.20 (m,1H, H7 chromene), 6.83 (d,1H, J ¼ 8 Hz, H8
chromene), 5.12 (d, 2H, J ¼ 1 Hz, OCH2). 13C NMR (125 MHz, CDCl3):
186.5, 154.1, 142.2, 136.8, 133.3, 132.5, 132.1, 130.7, 130.5, 128.5,
116.6, 65.3. IR (KBr, cmꢃ1
) nmax: 1751 (C]O), 1214 (C–O). MS (m/z,
%): 315 (Mþ1, 33), 314 (Mþ, 92), 233 (12), 220 (8), 191 (91), 165 (17),
133 (12), 123 (100), 109 (11), 101 (18), 95 (48), 75 (36), 51 (15). Anal.
Calcd for C18H12ClFO2: C, 68.69; H, 3.84. Found: C, 68.60; H, 3.96.
127.3, 126.6, 123.1, 121.9, 120.9, 117.7, 64.8. IR (KBr, cmꢃ1
) nmax: 1649
(C]O), 1178 (C–O). MS (m/z, %): 378 (Mþ2, 25), 376 (Mþ, 85), 359
(25), 295 (11), 267 (7), 260 (26), 231 (27), 219 (7), 202 (10), 165 (49),
155 (6),147 (19),130 (19),115 (12),102 (100), 89 (5), 75 (30), 63 (10),
51 (19). Anal. Calcd for C18H12BrClO2: C, 57.55; H, 3.22. Found: C,
57.41; H, 3.21.
3.3.2. (E)-3-(6-Chloro-2H-chromen-3-yl)-1-(2-chlorophenyl)-
prop-2-en-1-one (3b)
1H NMR (500 MHz, CDCl3)
d: 7.48–7.45 (m, 2H, H4 and H6
phenyl), 7.45–7.11 (m, 1H, H3 phenyl), 7.39–7.35 (m, 1H, H5 phenyl),
7.17 (dd, 1H, J ¼ 16 and 0.5 Hz, H3 propenone), 7.14 (dd, 1H, J ¼ 8.5
and 2.5 Hz, H7 chromene), 7.04 (d, 1H, J ¼ 2.5 Hz, H5 chromene),
6.78 (d, 1H, J ¼ 8.5 Hz, H8 chromene), 6.71 (brs, 1H, H4 chromene),
6.49 (d, 1H, J ¼ 16 Hz, H2 propenone), 5.03 (s, 2H, OCH2). IR (KBr,
3.4.2. (E)-1-(6-Chloro-2H-chromen-3-yl)-3-(4-methylphenyl)-
prop-2-en-1-one (4b)
1H NMR (500 MHz, CDCl3)
d: 7.74 (d, 1H, J ¼ 15.5 Hz, H3 pro-
penone), 7.54 (d, 2H, J ¼ 8 Hz, H2 and H6 phenyl), 7.37 (brs, 1H, H4
chromene), 7.33 (d, 1H, J ¼ 15.5 Hz, H2 propenone), 7.25 (d, 2H, J ¼ 8
Hz, H3 and H5 phenyl), 7.22 (dd, 1H, J ¼ 8.5 and 2.5 Hz, H7 chro-
mene), 7.19 (d, 1H, J ¼ 2.5 Hz, H5 chromene), 6.83 (d, 1H, J ¼ 8.5 Hz,
H8 chromene), 5.13 (d, 2H, J ¼ 1 Hz, OCH2), 2.41 (s, 3H, CH3). 13C
NMR (125 MHz, CDCl3): 187.0, 154.1, 144.1, 141.2, 132.8, 131.9, 131.8,
131.3, 129.7, 128.7, 128.5, 128.4, 126.5, 122.2, 118.7, 117.6, 65.0, 21.5.
cmꢃ1
)
nmax: 1741 (C]O). MS (m/z, %): 334 (Mþ4,16), 332 (Mþ2, 33),
330 (Mþ, 57), 314 (10), 260 (18), 222 (21), 192 (73), 167 (51), 141
(100), 130 (28), 114 (33), 58 (11). Anal. Calcd for C18H12Cl2O2: C,
65.28; H, 3.65. Found: C, 65.05; H, 3.66.
3.3.3. (E)-3-(6-Chloro-2H-chromen-3-yl)-1-(2,4-
IR (KBr, cmꢃ1
)
nmax: 1629 (C]O). MS (m/z, %): 312(Mþ2, 33), 310
dichlorophenyl)prop-2-en-1-one (3c)
(Mþ, 100), 293 (27), 267 (12), 232 (15), 218 (18), 202 (7), 165 (31),
155 (9), 145 (54), 130 (12), 115 (86), 102 (33), 91 (56), 75 (23), 65
(30), 51 (23). Anal. Calcd for C19H15ClO2: C, 73.43; H, 4.86. Found: C,
73.03; H, 4.78.
1H NMR (500 MHz, CDCl3)
d: 7.48 (d, 1H, J ¼ 2 Hz, H3 phenyl),
7.41 (d, 1H, J ¼ 8.5 Hz, H6 phenyl), 7.36 (dd, 1H, J ¼ 8.5 and 2 Hz, H5
phenyl), 7.18 (d, 1H, J ¼ 16 Hz, H3 propenone), 7.15 (dd, 1H, J ¼ 8.5
and 2.5 Hz, H7 chromene), 7.05 (d, 1H, J ¼ 2.5 Hz, H5 chromene),
6.79 (d, 1H, J ¼ 8.5 Hz, H8 chromene), 6.73 (s, 1H, H4 chromene),
6.47 (d, 1H, J ¼ 16 Hz, H2 propenone), 5.02 (s, 2H, OCH2). 13C NMR
(125 MHz, CDCl3): 193.1, 153.1, 141.9, 138.8, 131.6, 131.2, 130.7, 130.3,
129.8, 129.4, 127.3, 126.9, 126.8, 126.5, 125.6, 122.9, 117.2, 65.2. IR
3.4.3. (E)-1-(6-Chloro-2H-chromen-3-yl)-3-(2,5-
dimethoxyphenyl)prop-2-en-1-one (4c)
1H NMR (500 MHz, CDCl3)
d
: 8.00 (d, 1H, J ¼ 16 Hz, H3 prope-
none), 7.42 (d, 1H, J ¼ 16 Hz, H2 propenone), 7.35 (brs, 1H, H4
chromene), 7.22 (dd, 1H, J ¼ 8.5 and 2.5 Hz, H7 chromene), 7.19 (d,
1H, J ¼ 2.5 Hz, H5 chromene), 7.15 (d, 1H, J ¼ 3 Hz, H6 phenyl), 6.96
(KBr, cmꢃ1
)
nmax: 1654 (C]O), 1219 (C–O). MS (m/z, %): 369 (Mþ4,
13), 367 (Mþ2, 12), 365 (Mþ, 17), 329 (50), 265 (13), 220 (12), 203

Z. Nazarian et al. / European Journal of Medicinal Chemistry 45 (2010) 1424–1429
1429
(dd, 1H, J ¼ 9 and 3 Hz, H4 phenyl), 6.90 (d, 1H, J ¼ 9 Hz, H3 phenyl),
6.83 (d, 1H, J ¼ 8.5 Hz, H8 chromene), 5.14 (s, 2H, OCH2), 3.89 and
3.84 (2s, 6H, OCH3). 13C NMR (125 MHz, CDCl3): 187.5, 154.1, 153.5,
153.4, 139.4, 132.9, 131.7, 131.3, 128.3, 126.5, 124.3, 122.3, 120.9,
at a wavelength of 492 nm. Two or more independent experiments
in triplicate were performed for determination of sensitivity to each
drug, the IC50 were calculated by linear regression analysis,
expressed in mean ꢁ SD. Control cells were incubated with culture
medium plus DMSO.
117.6, 117.2, 113.9, 112.5, 65.1, 56.1, 55.9. IR (KBr, cmꢃ1
) nmax: 1644
(C]O). MS (m/z, %): 358 (Mþ2, 38), 356 (Mþ, 100), 324 (12), 306
(15), 297 (22), 281 (8), 262 (11),191 (25),176 (67),164 (75),148 (38),
133 (45), 102 (42), 89 (20), 77 (50), 63 (20), 51 (37). Anal. Calcd for
C20H17ClO4: C, 67.32; H, 4.80. Found: C, 67.11; H, 5.17.
3.5.3. Cytotoxicity against macrophages
In vitro toxicity against mouse peritoneal macrophages was
assessed with cells plated in 96-well plates at 2 ꢄ 105 cells/well.
After cell adherence, the medium was removed and replaced by the
media containing IC50 concentration of each compounds. The plates
were incubated for 24 h at 37 ꢀC in a humidified incubator with 5%
CO2. Control cells were incubated with culture medium plus DMSO.
Cell viability was determined by MTT colorimetric assay.
3.4.4. (E)-1-(6-Chloro-2H-chromen-3-yl)-3-(2,3-
dimethoxyphenyl)prop-2-en-1-one (4d)
1H NMR (500 MHz, CDCl3)
d: 8.03 (d, 1H, J ¼ 16 Hz, H3 prope-
none), 7.43 (d, 1H, J ¼ 16 Hz, H2 propenone), 7.36 (brs, 1H, H4
chromene), 7.26 (dd, 1H, J ¼ 8.5 and 1.5 Hz, H7 chromene), 7.21 (dd,
1H, J ¼ 8.5 and 1.5 Hz, H6 phenyl), 7.17 (d, 1H, J ¼ 1.5 Hz, H5 chro-
mene), 7.12 (t,1H, J ¼ 8.5 Hz, H5 phenyl), 6.99 (dd,1H, J ¼ 8.5 and 1.5
Hz, H4 phenyl), 6.83 (d, 1H, J ¼ 8.5 Hz, H8 chromene), 5.14 (d, 2H, J ¼
1.5 Hz, OCH2), 5.91 and 3.89 (2s, 6H, OCH3). 13C NMR (125 MHz,
CDCl3): 187.3, 154.1, 153.2, 148.9, 138.9, 132.8, 131.8, 131.4, 128.9,
128.4, 126.5, 124.2, 122.2, 121.3, 119.5, 117.6, 114.2, 64.9, 61.3, 55.9. IR
Acknowledgments
This work was supported by a grant from Tehran University of
Medical Sciences.
(KBr, cmꢃ1
)
nmax: 1639 (C]O). MS (m/z, %): 358 (Mþ2, 41), 356 (Mþ,
References
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164 (65), 155 (9), 148 (25), 133 (25), 102 (40), 91 (24), 77 (46), 63
(17), 51 (35). Anal. Calcd for C20H17ClO4: C, 67.32; H, 4.80. Found: C,
67.21; H, 4.69.
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