Synthesis and QSAR analysis of chalcone derivatives as nitric oxide inhibitory agent

Article abstract of DOI:10.1007/s00044-011-9706-1

In this study, thirty-eight chalcone analogs were synthesized and evaluated for nitric oxide (NO) inhibition activity on RAW 264.7 cells. Among these compounds, chalcones bearing furanyl group showed remarkable anti-inflammatory activity. Both compounds 2d and 2j were identified as the most potent NO inhibitor on IFN-γ/LPS-activated RAW 264.7 cells. In order to examine the structure-activity relationship, a 3D QSAR analysis was carried out by comparative molecular field analysis (CoMFA) method on the selected chalcones. Partial least square analysis produced a statistically coherent model with good predictive value, r² = 0.989 and a good cross validated value, q ² = 0.583.

Full text of DOI:10.1007/s00044-011-9706-1

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:1953–1966
DOI 10.1007/s00044-011-9706-1
ORIGINAL RESEARCH
Synthesis and QSAR analysis of chalcone derivatives
as nitric oxide inhibitory agent
•
Kok Wai Lam Reaz Uddin Choi Yi Liew Chau Ling Tham
•
•
•
•
Daud A. Israf Ahmad Syahida Mohd. Basyaruddin Abdul Rahman
•
•
•
Zaheer Ul-Haq Nordin H. Lajis
Received: 3 June 2010 / Accepted: 11 June 2011 / Published online: 9 July 2011
Ó Springer Science+Business Media, LLC 2011
Abstract In this study, thirty-eight chalcone analogs
were synthesized and evaluated for nitric oxide (NO)
inhibition activity on RAW 264.7 cells. Among these
compounds, chalcones bearing furanyl group showed
remarkable anti-inflammatory activity. Both compounds 2d
and 2j were identified as the most potent NO inhibitor on
IFN-c/LPS-activated RAW 264.7 cells. In order to examine
the structure–activity relationship, a 3D QSAR analysis
was carried out by comparative molecular field analysis
(CoMFA) method on the selected chalcones. Partial least
square analysis produced a statistically coherent model
with good predictive value, r2 = 0.989 and a good cross
validated value, q2 = 0.583.
Keywords Nitric oxide inhibition ꢀ Chalcone analogues ꢀ
RAW 264.7 ꢀ 3D QSAR ꢀ CoMFA
Introduction
Chalcone is a diarylpropanoid commonly found throughout
the plant kingdom and acts as precursor for biosynthesis of
flavonoids. Despite their structural simplicity, these com-
pounds exhibit diverse important pharmacological effects
on biological systems including anti-inflammatory (Correa
et al., 2001), anti-mycobacterial (Rojas et al., 2002), anti-
malarial (Chen et al., 1994), anti-fungal (Boeck et al.,
2006; Lopez et al., 2001), anti-viral (Phrutivorapongkul
et al., 2003), and anti-nociceptive (Correa et al., 2001).
Previous studies have shown that chalcones bearing phenyl
group with chloro and hydroxyl substituents inhibit nitric
oxide (NO) synthesis as well as inducible nitric oxide
synthase (iNOS) protein expression in RAW 264.7 cells
(Ko et al., 2003; Won et al., 2005). The synthetic chalcone
20,50-dihydroxy-4-chlorodihydrochalcone was found to
inhibit the cyclooxygenase-2 (COX-2) activity in RAW
264.7 cells (Huang et al., 2001). In our own study on
cardamonin, a naturally occurring chalcone isolated from
the fruits of Alpinia rafflesiana, we found that it suppressed
both NO and PGE2 in interferon-c (IFN-c)- and lipopoly-
saccharide (LPS)- induced RAW 264.7 cells (Ahmad et al.,
2006; Israf et al., 2007).
K. W. Lam ꢀ N. H. Lajis (&)
Laboratory of Natural Products, Institute of Bioscience,
University Putra Malaysia, 43400 UPM Serdang,
Selangor Darul Ehsan, Malaysia
e-mail: nhlajis@ibs.upm.edu.my
R. Uddin ꢀ Z. Ul-Haq
Dr. Panjwani Center for Molecular Medicine & Drug Research,
International Center for Chemical & Biological Sciences,
University of Karachi, Karachi 75270, Pakistan
C. Y. Liew ꢀ C. L. Tham ꢀ D. A. Israf
Department of Biomedical Sciences,
Faculty of Medicine and Health Sciences,
University Putra Malaysia, 43400 UPM
Serdang, Selangor Darul Ehsan, Malaysia
A. Syahida
Department of Biochemistry,
Faculty of Biotechnology and Molecular Sciences,
University Putra Malaysia, 43400 UPM Serdang,
Selangor Darul Ehsan, Malaysia
In order to explore further the interaction and effects of
chalcone derivatives on inflammatory mediators, we syn-
thesize further analogs of this class of compounds and
establish the structure–activity relationship as the initial
Mohd. B. A. Rahman ꢀ N. H. Lajis
Department of Chemistry, Faculty of Science,
University Putra Malaysia, 43400 UPM Serdang,
Selangor Darul Ehsan, Malaysia
123

1954
Med Chem Res (2012) 21:1953–1966
step. Three dimensional quantitative structure–activity
relationship (3D QSAR) is an approach utilized in drug
design. This approach is based on the physicochemical
Discussion
CH3
O
N
O
O
CH3
;
;
B =
;
O
β
(1a-d)
(2a-q)
(4a-b)
CH3
B
(3a-d)
A
X
α
S
S
Cl
;
or
N
(5a-b)
(7a-d)
(6a-c)
Structure–activity relationship (SAR)
factors, steric and electrostatic field of the compound, and
correlates them with biological activities. This effort is
expected to allow us to understand the relationship between
the physicochemical features of a compound with biolog-
ical activities, and further design the more potentially
effective drugs in a rational way. 3D QSAR analysis was
applied to correlate the structure of chalcones and its bio-
logical activities have been reported (Chiaradia et al.,
2008; Liu and Go, 2007; Sivakumar et al., 2007; Xue et al.,
2004). However, to the best of our knowledge, no 3D
QSAR of chalcone and its NO inhibitory activity, as a
preliminary investigation on its potential as anti-inflam-
matory agent, have not been undertaken.
The NO inhibition activity of the synthesized chalcone
derivatives on IFN-c/LPS-activated macrophage cells is
summarized in Table 1, with L-NAME used as positive con-
trol. The suppression of cell viability affected by all deriva-
tives did not fall in close proximity to the IC50 of NO
inhibition, and therefore, the inhibitory effect upon NO
secretion was apparently not duetocell death. Theresultsalso
clearly indicated that compounds exhibiting significant NO
inhibitory activity may be related to the presence of aromatic
rings(A andB)andavinylketonemoiety. Thechalconesfrom
series 2 exhibited higher NO suppression relative to other
series with IC50 values ranging from 2.26 lM to more than
50 lM. The trend of NO inhibitory activity appeared to be in
the order of 2 [ 3 [ 1 [ 7 [ 6 [ 4 [ 5. One of the main
reasonscontributingtothestrikingeffectsofNOinhibitionby
compounds from series 2, 3, and 1 may be related to the
presence of furanyl moiety in the compounds.
Results
Synthesis
The NO suppression effect was further analyzed based
on different theoretical parameters according to Lipinski
criteria, which include logP, molecular weight and volume
as well on the number of hydrogen bond donor and
acceptor groups present (Lipinski et al., 2001). Based on
this analysis, all active NO inhibitors from series 2 recor-
ded logP value of lower than 5, and thus fulfilled
the Lipinski rules, which requires that most ‘‘drug-like’’
molecules should not exceed this value. Only compounds
2e and 2r from this series showed poor NO suppression.
These chalcone analogs possessed low logP values, which
is associated with their high hydrophilic character. This in
turn may restrict their capability to cross the hydrophobic
barrier in cells or in ligand binding in the active site.
Similar instance was also observed in the case of series 4
and 5 compounds, which recorded a low logP values in the
region of 2, and could be rationalized as to be due to the
presence of pyridinyl ring (ring B). These compounds
The general synthetic pathways for the preparation of the
desired compounds are represented in Scheme 1. All
chalcones were prepared based on Claisen-Schmidt con-
densation between the aromatic aldehydes and selected
ketones. In general, the protection of hydroxylated aro-
matic aldehydes in the form of tetrahydropyranyl ether was
required before base-catalyzed aldol condensation step.
Deprotection using strong p-toluenesulfonic acid was
conducted to achieve the desired respective products.
However, this general strategy was not successful in the
case of hydroxylated aromatic aldehyde at ortho position.
The higher concentration of base with longer reflux time
was required to accomplish satisfactory yields. Carboxy-
methylation of para-hydroxybenzaldehyde was accom-
plished by reacting it with a-chloroacetic acid in the
presence of sodium hydroxide. All compounds were char-
1
acterized by H, 13C NMR, EI-mass spectrometry and IR
analysis.
123

Med Chem Res (2012) 21:1953–1966
1955
O
O
O
O
(i)
H
(ii)
(iii)
B
B
H
HO
THPO
B =
THPO
HO
(III)
(I)
(II)
O
O
CH3
N
O
S
O
CH3
H (iv)
B
O
;
;
;
X
X
CH3
(IV)
S
Cl
;
or
X = -OH; -OCH3; di -OCH3; tri -OCH3;
-OCH2COOH; F; or Cl.
N
HOOCCH2
(vi)
HOOCCH2
O
O
OH
O
O
O
(v)
B
H
H
(V)
(VI)
O
O
O
O
(vii)
O
H
(VII)
Scheme 1 Synthetic scheme for chalcone analogs. Reagents and
conditions: (i) 3,4-dihydro-2H-pyran, pyridinium p-toluenesulfonate,
CH2Cl2, 4 h. (ii) respective heterocyclic ketone, NaOH, ethanol, reflux.
(iii) TsOH, methanol, rt, 2 h. (iv) respective aldehyde, respective
heterocyclic ketone, NaOH, ethanol, reflux. (v) a-chloroacetic acid,
NaOH, reflux, 4 h. (vi) respective heterocyclic ketone, NaOH, ethanol,
reflux. (vii) 2-acetylfuran, NaOH, ethanol, reflux
displayed only moderate NO inhibition activity. According
to Lipinski, logP is an important feature for good drug
absorption and permeation (Balanco et al., 1998; Tetko
et al., 2005; Veber et al., 2002).
On the other hand, the presence of electron donating
group such as hydroxyl group at ortho position in the phenyl
ring A appeared to be an important factor for NO sup-
pression in the series 1, 2, 4, 5, 6, and 7. Analog 2a, bearing
ortho-hydroxyl group in ring A recorded significant sup-
pression of nitrite with an IC50 value of 5.88 0.38 lM,
while 5a recorded a lower activity with an IC50 value of
31.74 1.21 lM. These results suggest that the presence
of ortho phenolic hydroxy group at ring A was vital for the
suppression of NO secretion in RAW 264.7. This was fur-
ther supported by the fact that replacing the proton of ortho-
hydroxyl into an acetic acid group in compounds 2e and 3d
totally masked the NO inhibition activity.
Correlating the structural feature of ring B with the
activity revealed that furanyl radical generally recorded
higher NO inhibitory activity than pyridinyl or thiophenyl
analogs. Both of these compounds did not violate any of
the Lipinski rules. Structurally, the only major difference is
the replacement of oxygen with sulfur atom in the five-
membered ring B. This observation could be best explained
by the fact that the oxygen species in furan ring might have
a higher hydrogen bond accepting capacity compared with
the sulfur species in the thiophenyl derivatives. In the case
of thiophene, H-bond formation is more susceptible toward
the aromatic pi system as compared with the unshared
electron pair localized at S atom. In contrast, the oxygen
atom in the furanyl ring is more capable of forming
hydrogen bond through its non-bonding electron pair
(Cooke et al., 1998). The pyridinyl derivatives from series
4 and 5 demonstrated minimal NO inhibition compared
with the furanyl and thiophenyl series, which could be
rationalized by the larger ring size of B, thus prohibiting its
occupancy in the active site of the mediators in NO
production.
Among the compounds in series 3, in which ring
B consisted of 2,5-dimethylfuran ring, the highest NO
suppression was observed when the hydroxyl substituent
was located at meta-position at ring A. This was in contrast
to the related compounds from series 2. m-Hydroxylated
phenyl ring in this group of compounds exhibited lower
IC50 value than those analogs from series 1 and 2. This
change in activity trend may be related to the change of
location of the oxygen atom in ring B, resulting in the
alteration of their interaction with the mediators.
The results presented in Fig. 1 show that analogs 2j and 2r
inhibited NO secretion in a dose-dependent manner. The most
123

1956
Med Chem Res (2012) 21:1953–1966
Table 1 The IC50 values of anti-inflammatory activity and the Lipinski’s Rule of five values for chalcone derivatives
Compound Substituted position
(series)
Ring B
Anti-inflammatory activity
IC50 (lM) (Mean SEMa)
Lipinski Rule of 5b
in phenyl ring A, X
miLogP Volume
MW
HBA HBD
1a
1b
1c
1d
2a
2b
2c
2d
2e
o-hydroxy
19.33 2.82
24.76 2.64
24.89 3.29
16.02 0.97
5.88 0.38
9.35 0.95
16.29 0.63
2.51 0.42
C50
2.829
2.565
2.589
2.930
3.051
2.787
2.811
3.152
2.365
3.249
3.137
2.939
3.259
2.931
3.128
3.226
3.430
191.438 214.220
191.438 214.220
191.438 214.220
234.512 258.273
207.999 228.247
207.999 228.247
207.999 228.247
251.073 272.300
252.769 286.283
223.315 257.245
276.618 302.326
276.618 302.326
230.458 260.264
251.073 272.300
251.073 272.300
204.913 230.238
204.913 230.238
3
3
3
4
3
3
3
4
5
5
5
5
3
4
4
2
2
1
1
1
0
1
1
1
0
1
0
0
0
0
0
0
0
0
m-hydroxy
p-hydroxy
2,5-dimethoxy
o-hydroxy
m-hydroxy
p-hydroxy
2,5-dimethoxy
o-(2-oxyacetic acid)
14.51 1.34
5.62 1.52
4.47 1.47
5.31 0.60
2.26 0.47
6.45 1.50
12.87 2.45
16.06 3.78
2f
p-nitro
2g
2h
2i
2,4,6-trimethoxy
2,3,4-trimethoxy
2-fluoro,4-methoxy
2,3-dimethoxy
2,6-dimethoxy
o-fluoro
2j
2k
2l
2m
2n
2o
2p
2q
2r
3a
3b
3c
3d
4a
4b
5a
5b
5c
6a
6b
6c
7a
7b
7c
7d
9a
8a
m-fluoro
p-fluoro
17.04 2.82
16.98 4.51
7.76 1.32
11.48 1.86
21.31 2.15
13.78 0.28
7.96 0.10
13.50 2.03
C50
3.454
3.741
3.944
3.968
2.368
2.962
2.698
2.722
2.276
2.402
2.138
2.283
2.019
2.043
3.471
3.231
3.572
4.273
4.009
4.033
4.374
ND
204.913 230.238
213.517 246.693
213.517 246.693
213.517 246.693
181.549 202.209
224.560 242.274
224.560 242.274
224.560 242.274
269.330 300.310
205.714 225.247
205.714 225.247
205.714 225.247
205.714 225.247
205.714 225.247
200.582 230.288
200.582 230.288
243.656 274.341
214.118 264.733
214.118 264.733
214.118 264.733
257.191 308.786
2
2
2
2
3
3
3
3
5
3
3
3
3
3
2
2
3
2
2
2
3
ND
4
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
0
ND
2
o-chloro
m-chloro
p-chloro
Furan
o-hydroxy
m-hydroxy
p-hydroxy
o-(2-oxyacetic acid)
o-hydroxy
29.95 1.07
49.51 1.18
31.74 1.21
C50
m-hydroxy
o-hydroxy
m-hydroxy
p-hydroxy
C50
o-hydroxy
16.22 0.18
46.82 0.95
38.71 0.24
23.43 1.02
33.28 1.63
C50
p-hydroxy
2,5-dimethoxy
o-hydroxy
m-hydroxy
p-hydroxy
2,5-dimethoxy
L-NAMEc
26.04 0.83
23.21 1.64
11.48 1.25
–
–
ND
ND
cardamonin
3.233
243.434 270.284
ND not determined
a
Standard error of the mean
b
Calculation was generated out online www.molinspiration.com website (Molinspiration Property Engine v2009.01)
Positive control used for anti-inflammatory assay
c
123

Med Chem Res (2012) 21:1953–1966
1957
25
20
15
10
5
25
20
*
15
10
***
**
5
***
***
***
***
C
*** *** ***
***
C
0
***
0
μM
0.78 1.56 3.13 6.25 12.50 25.00 50.00250.00
0
μM
0.78 1.56 3.13 6.25 12.50 25.00 50.00250.00
0
L-NAME
compound 2j
IFN-γ/LPS
compound 2r
IFN-γ/LPS
L-NAME
Fig. 1 Nitric oxide (NO) production level of RAW 264.7 in the
presence of compounds 2j and 2r. C: basal level of nitrite concen-
tration without IFN-c/LPS treatment. All values are mean SEM. of
three different experiments. *P \ 0.05, **P \ 0.01, ***P \ 0.001
significantly different from the IFN-c/LPS-treated control group
CoMFA analysis
active compound 2j suppressed the NO production signifi-
cantly, with an IC50 value of 2.26 0.47 lM, which repre-
sents almost a10-fold and 5-foldimprovementcomparedwith
positive inhibitor, L-NAME and cardamonin, respectively.
Compound 2r recorded less significant NO inhibition with an
IC50 value of 21.31 2.15 lM, which suggested that a six-
membered phenyl ring in A might be required for the NO
inhibition. In another related study on compound 2j, it was
suggested that the NO inhibition was due to the down-regu-
lation of inducible nitric oxide synthase (iNOS), and cyclo-
oxygenase-2(COX-2),withoutanydirecteffectuponiNOSor
COX-2 enzyme activity (Liew et al. 2010).
QSAR with CoMFA was widely used in correlating the
activity with molecular structure utilizing a set of physi-
cochemical parameters (Cramer Iii et al., 1988). The
results from the statistical and graphical analyses can be
employed to optimize the efficacy and safety of drug
candidates through structural modification of the active
templates. In this study, CoMFA method was adopted with
Partial Least Squares (PLS) regression on NO inhibitory
effect toward IFN-c/LPS-activated RAW 264.7. CoMFA
analysis was performed on 22 selected compounds and 18
of them were assigned as training sets (n = 18), while the
other four as test sets (n = 4). A predictive CoMFA model
on the basis of the common substructure-based alignment
was generated in Table 2 with the conventional correlation
coefficient r2 = 0.963 and cross-validation q2 = 0.583,
while both the steric and electrostatic fields contribute
71.7% and 28.3%, respectively (Table 3). The results
showed that steric interaction played a major role in the
NO inhibition activity. Finally, four test sets were assigned
Figure 2 represents the effect of compounds 2j and 2r
upon the viability in RAW 264.7 cells. It is evident that
compound 2j is toxic to cells at the concentrations of
25 lM and above, whereas 2r does not. Therefore, it was
obvious that the large difference in toxicity between 2j and
2r could be associated with the substituent pattern in ring
A. Thus, replacement of 2,3-dimethoxyphenyl ring with
furanyl in radical A resulted in an improvement to cell
viability below the 50 lM concentration level (Table 1).
150
150
**
*
**
100
50
0
***
100
***
***
***
***
50
0
***
***
***
C
0
0.78 1.56 3.13 6.25 12.50 25.00 50.00250.00
μM
C
0
0.78 1.56 3.13 6.25 12.50 25.00 50.00250.00
μM
L-NAME
compound 2r
IFN-γ/LPS
L-NAME
compound 2j
IFN-γ/LPS
Fig. 2 RAW 264.7 cell viability in the presence of compounds 2j and
2r. C: basal level of nitrite concentration without IFN-c/LPS
treatment. All values are mean SEM of three different experiments.
*P \ 0.05, **P \ 0.01, ***P \ 0.001 significantly different from the
IFN-c/LPS-treated control group
123

1958
Med Chem Res (2012) 21:1953–1966
could also be found in the region of ortho position in ring
A. For example, compounds in series 2, which contain
methyl group in the furanyl ring (radical B), displayed
higher NO inhibition than compounds from series 1. The
prominent NO suppressive effects shown by those com-
pounds containing methyl substituent in ring B proved to
be an interesting new observation. These results also sug-
gest that bulky substituent at this region is highly favorable
for NO inhibition potency. Large-sized yellow-colored
isopleths representing bulky favorable could be found in
both meta positions in ring A.
Table 2 Comparison of experimental and calculated biological
activities of selected compounds by using CoMFA
No.
Compound
Actual
pIC50
CoMFA predicted
pIC50
Residual
Training set
1
2
1a
1b
1c
1d
2b
2c
2d
2g
2h
2i
4.71
4.61
4.60
4.80
5.03
4.79
5.60
5.25
5.35
4.91
5.65
5.19
4.89
4.79
4.77
5.11
4.94
4.67
4.69
4.65
4.51
4.87
5.05
4.82
5.55
5.28
5.34
4.91
5.63
5.21
4.83
4.95
4.76
4.99
4.95
4.67
0.02
-0.04
0.09
3
6
-0.07
-0.02
-0.03
0.05
4
5
The regions with red isopleths, which are defined as
electrostatic favorable areas with negative charge could be
found in the region of ortho and para position in ring A,
suggesting that electron withdrawing groups in the ortho
and meta position are highly favorable. A large-sized blue-
colored isopleths encompassing the other side of ortho and
meta position in ring A, suggesting that positive charge
preference to enhance NO inhibition activity. Since most of
the active compounds contain hydroxyl group in this blue
region, it is therefore important to assume that the presence
of electronegative atom in the para and meta position
might be involved in the hydrogen bonding interaction with
the target moieties in this region. For example, compounds
2d, 2j, and 2a exhibited more potent NO inhibition than
other compounds in the same series because of the pres-
ence of ortho hydroxy and methoxy group in ring A, which
is necessary in affecting the NO suppression activity in the
cell.
7
8
-0.03
0.01
9
10
11
12
13
14
15
16
17
18
Test set
19
20
21
22
0.00
2j
0.02
2k
2l
-0.02
0.06
2m
2o
2p
2q
2r
-0.15
0.01
0.12
-0.01
0.00
2a
5.16
4.84
4.77
4.94
5.06
5.00
4.98
4.61
0.10
-0.17
-0.21
0.33
2f
2n
Cardamonin
Experimental
to validate the reliability of the model as presented in
Fig. 3.
Chemistry
The steric contour field map was plotted as shown in
Fig. 4. The green isopleths represent the favorable steric
group while the yellow isopleths represent the less favor-
able. The small-sized green-colored isopleths are found
surrounding the methyl group in ring B. Green isopleths
All the chemicals and reagents were purchased from the
suppliers including Sigma–Aldrich and Merck and Acros
Organics chemical companies. All the solvents used in this
experiment were either of HPLC-grade or dried and dis-
tilled before use. Typical work-ups include washing with
brine and drying the organic layer with magnesium sulfate
(anhydrous) followed by concentration in vacuo. Analytic
TLC was carried out on silica gel F254 precoated (0.2 mm
thickness, Merck) on aluminum sheets. The TLC plates
were spotted with the samples using a fine glass capillary
tube and developed in a chromatographic tank saturated
with solvent vapor at room temperature. The IR spectra
were recorded on a Perkin Elmer RXI FT-IR spectrometer
as KBr disk or thin film. Mass spectra were measured on
Thermo Finnigan POLARISQ spectrometer, with ioniza-
tion induced by electron impact at 70 eV. Nuclear Mag-
netic Resonance Spectra were recorded in CDCl3, CD3OD,
or DMSO-d6 using Varian 500 MHz NMR Spectrometer.
5.8
5.6
5.4
5.2
5
CoMFA training
4.8
CoMFA test
4.6
CoMFA Cardamonin
4.4
4.2
4.2
4.7
5.2
5.7
6.2
Fig. 3 Plots of the predicted versus experimental activity data of
3D-QSAR from CoMFA for the training and the test compounds
123

Med Chem Res (2012) 21:1953–1966
1959
Fig. 4 Electrostatic and steric maps from the CoMFA model.
a Favorable electrostatic areas with positive charges are indicated
by blue isopleths, whereas favorable electrostatic areas with negative
charges are shown by red isopleths. b Favorable steric areas with
more bulkiness are indicated by green isopleths, whereas the
disfavorable steric areas are shown by yellow isopleths
water was added into the mixture, and the product was
extracted with EA. The EA layer was concentrated in
vacuo, and the final product was dried using magnesium
sulfate anhydrous and used in the next step without further
purification.
Table 3 Summary of CoMFA analysis
CoMFA model
Result
R2 cross validated (q2)
SEP
0.583
0.254
6
Number of components
Non cross-validated r2
Standard error of estimate
F
0.963
0.076
47.725
0.717
0.283
0.989
0.126
General procedures for the synthesis of III
The crude product from previous reaction (II) and catalytic
amount of p-toluenesulfonic acid were dissolved in meth-
anol. The mixture was stirred for 2 h, and the reaction was
monitored by TLC. Once the reaction was completed, the
mixture was washed with 40 ml water, neutralized with
Na2CO3 and extracted with ethyl acetate. The organic layer
was concentrated in vacuo and subjected to further purifi-
cation using column chromatography.
Steric contribution
Electostatic contribution
Predicted r2
Predicted r2 with cardamonin
General procedures for the synthesis of I
para- or meta-Hydroxylated aromatic aldehyde (10 mmol)
was suspended in dichloromethane in the presence of py-
ridinium p-toluene sulfonate (10 mmol). The mixture was
stirred at room temperature followed by the addition of
5 ml of 3,4-dihydropyran in dropwise manner. Then, the
mixture was stirred monitored by TLC for another 4 h.
Once the reaction was completed, the mixture was washed
with water and extracted with ethyl acetate (EA). The EA
layer was concentrated in vacuo, and the final product
appeared as clear oils.
General procedures for the synthesis of IV
Into a 150 ml single-necked round-bottomed flask con-
taining a vigorously stirred mixture of appropriate aromatic
aldehyde (10 mmol, 1 equiv) and ketone (10 mmol, 1
equiv) in 20 ml of absolute ethanol, a few drops of 40%
NaOH in ethanol was slowly added. The stirring was
continued and refluxed for 2 h. Upon completion, 100 ml
of distilled water was added and further extracted with EA.
The EA layer was concentrated in vacuo and subjected to
further purification by recrystallization in appropriate sol-
vent or column chromatography.
General procedures for the synthesis of II
A mixture of 10 mmol of I and 10 mmol of appropriate
acetone (methyl heteroaryl ketone) in absolute ethanol was
stirred, and a few drops of 40% of NaOH in ethanol was
added. The mixture was stirred overnight at room tem-
perature. The reaction was checked by TLC on the fol-
lowing day. After the reaction was completed, 50 ml of
General procedures for the synthesis of V
A 20 ml aqueous solution of a mixture of 2-hydroxy-
benzaldehyde (10 mmol) and sodium hydroxide (20 mmol)
was stirred, and a-chloroacetic acid (10 mmol) was added
in a dropwise manner. The mixture was then heated under
123

1960
Med Chem Res (2012) 21:1953–1966
reflux in a water bath for 4 h. Following this, the solution
was acidified with 20 ml of concentrated hydrochloric acid
and was cooled in ice bath. The white crystals V was
formed and filtered off followed by rinsing with water.
Further recrystallization was conducted from appropriate
solvent. The reaction yielded a pure crystalline product.
J = 3.5 Hz, 1H, H-4 furanyl), 7.76 (t, J = 8.0 Hz, 1H, H-5
phenyl), 7.84 (d, J = 1.5 Hz, 1H, H-2 furanyl), 8.12 (d,
J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz, CD3OD): d
112.7, 114.7, 118.0, 118.9, 120.2, 121.0, 130.0, 136.1,
144.5, 148.0, 153.6, 157.9, 178.6; EIMS m/z (rel. int.) calcd
for C13H10O3 (M?, %): 214 (M?, 74).
1-(furan-2-yl)-3-(4-hydroxyphenyl)prop-2-en-1-one (1c)
Yield: 50%; yellow powder; IR(KBr) mmax: 3430 (–OH),
1644 (C=O), 1572 (C=C), 1462, 1051, 826; 1H NMR
(500 MHz, CD3OD): d 6.69 (dd, J = 3.5/1.5 Hz, 1H, H-3
furanyl), 6.86 (d, J = 8.5 Hz, 2H, H-3/5 phenyl), 7.43 (d,
J = 15.5 Hz, 1H, H-a), 7.52 (d, J = 3.5 Hz, 1H, H-4
furanyl), 7.61 (d, J = 8.5 Hz, 2H, H-2/6 phenyl), 7.80 (d,
J = 15.5 Hz, 1H, H-b), 7.83 (d, J = 1.5 Hz, 1H, H-2
furanyl). 13C NMR (125 MHz, CD3OD): d 112.6, 115.7,
115.8, 117.7, 118.3, 126.3, 130.8, 144.8, 147.7, 160.7,
178.9; EIMS m/z (rel. int.) calcd for C13H10O3 (M?, %):
214 (M?, 69).
General procedures for the synthesis of VI
The product V (10 mmol) was further reacted with selected
10 mmol of aldehyde in the presence of catalytic amount of
40% sodium hydroxide in 20 ml of absolute ethanol. The
mixture was refluxed in a water bath for an hour. Water
(50 ml) was then added, and the product was extracted with
EA and concentrated in vacuo. The EA soluble extract was
then subjected to purification using silica gel column
chromatography.
General procedures for the synthesis of (VII)
3-(2,5-dimethoxyphenyl)-1-(furan-2-yl)prop-2-en-1-one
(1d); Yield: 62%; IR(KBr) mmax: 2940 (C–H stretch), 1654
(C=O), 1594 (C=C), 1495 (C=C), 1464, 1260 (C–O aro-
matic), 1220, 1046; 1H NMR (500 MHz, CDCl3): d 3.80 (s,
3H, OCH3), 3.85 (s, 3H, OCH3), 6.57 (dd, J = 3.5/1.5 Hz,
1H, H-3 furanyl), 6.87 (d, J = 8.5 Hz, 1H, H-3 phenyl),
6.94 (dd, J = 8.5 Hz/3.0 Hz, 1H, H-4 phenyl), 7.16 (d,
J = 3.0 Hz, 1H, H-6 phenyl), 7.31 (d, J = 3.5 Hz, 1H, H-4
furanyl), 7.50 (d, J = 16.0 Hz, 1H, H-a), 7.64 (d,
J = 1.5 Hz, 1H, H-2 furanyl), 8.17 (d, J = 16.0 Hz, 1H,
H-b). 13C NMR (125 MHz, CDCl3): d 50.0, 56.4, 112.6,
113.9, 117.6, 117.7, 122.2, 124.5, 126.4, 139.5, 146.6,
146.7, 153.7, 154.1, 178.7; EIMS m/z (rel. int.) calcd for
C15H14O4 (M?, %): 258 (M?, 12).
Into a 150 ml single-necked round-bottomed flask con-
taining a vigorously stirred mixture of appropriate aromatic
aldehyde (10 mmol, 1 equiv) and ketone (10 mmol, 1
equiv) in 20 ml of absolute ethanol, a few drops of 40%
NaOH in ethanol was slowly added. The stirring was
continued and refluxed for 2 h. Upon completion, 100 ml
of distilled water was added and further extracted with EA.
The EA layer was concentrated in vacuo and subjected to
further purification by recrystallization in appropriate sol-
vent or column chromatography.
Spectral data
3-(2-hydroxyphenyl)-1-(5-methylfuran-2-yl)prop-2-
en-1-one (2a) Yield: 53%; orange needle crystals; IR(KBr)
1-(furan-2-yl)-3-(2-hydroxyphenyl)prop-2-en-1-one (1a)
Yield: 42%; yellow crystals; IR(KBr) mmax: 3248 (–OH),
1644 (C=O), 1578 (C=C), 1459, 1052, 756; 1H NMR
(500 MHz, CD3OD): d 6.66 (dd, J = 3.5/1.5 Hz, 1H, H-3
furanyl), 6.86 (t, J = 7.5 Hz, 1H, H-5 phenyl), 6.88 (d,
J = 8.0 Hz, 1H, H-3 phenyl), 7.23 (td, J = 8.0/1.5 Hz, 1H,
H-4 phenyl), 7.46 (d, J = 3.5 Hz, 1H, H-4 furanyl), 7.63
(dd, J = 7.5/1.5 Hz, 1H, H-6 phenyl), 7.66 (d, J = 16.0 Hz,
1H, H-a), 7.81 (d, J = 1.5 Hz, 1H, H-2 furanyl), 8.18
(d, J = 16.0 Hz, 1H, H-b). 13C NMR (125 MHz, CD3OD):
d 112.6, 116.02, 118.4, 119.8, 120.6, 121.8, 129.3, 132.1,
140.5, 147.7, 153.8, 157.8, 179.3; EIMS m/z (rel. int.) calcd
for C13H10O3 (M?, %): 214 (M?, 8).
m
max: 3281 (–OH), 1640 (C=O), 1586 (C=C), 1511 (C=C),
1252 (C–O aromatic), 1073, 756; 1H NMR (500 MHz,
CD3OD): d 2.40 (s, 3H, CH3), 6.30 (d, J = 2.5 Hz, 1H,
H-4 furanyl), 6.85 (t, J = 8.0 Hz, 1H, H-5 phenyl), 6.89 (d,
J = 8.0 Hz, 1H, H-3 phenyl), 7.23 (t, J = 8.0 Hz, 1H, H-4
phenyl), 7.39 (d, J = 2.5 Hz, 1H, H-3 furanyl), 7.59 (d,
J = 16.0 Hz, 1H, H-a), 7.62 (d, J = 8.0 Hz, 1H, H-5
phenyl), 8.14 (d, J = 16.0 Hz, 1H, H-b). 13C NMR
(125 MHz, CD3OD): d 12.8, 109.4, 109.5, 115.9, 119.7,
120.7, 121.9, 129.1, 131.9, 139.8, 152.6, 157.7, 159.1,
178.6; EIMS m/z (rel. int.) calcd for C14H12O3 (M?, %):
228 (M?, 12).
1-(furan-2-yl)-3-(3-hydroxyphenyl)prop-2-en-1-one (1b)
Yield: 56%; yellow crystals; IR(KBr) mmax: 3307 (–OH),
1654 (C=O), 1594 (C=C), 1460, 1278 (C–O aromatic),
1051, 765; 1H NMR (500 MHz, CD3OD): d 6.69 (dd,
J = 3.5/1.5 Hz, 1H, H-3 furanyl), 6.86 (d, J = 8.0 Hz, 1H,
H-4 phenyl), 7.12 (s, 1H, H-2 phenyl), 7.19 (d, J = 8.0 Hz,
1H, H-6 phenyl), 7.52 (d, J = 15.5 Hz, 1H, H-a), 7.54 (d,
3-(3-hydroxyphenyl)-1-(5-methylfuran-2-yl)prop-
2en-1-one (2b) Yield: 79%; yellow flakes; IR(KBr) mmax
:
3306 (–OH), 1648 (C=O), 1593 (C=C), 1511 (C=C), 1282
(C–O aromatic), 1072, 783; 1H NMR (500 MHz, CD3OD):
d 2.42 (s, 3H, CH3), 6.34 (d, J = 3.0 Hz, 1H, H-4 furanyl),
6.88 (dd, J = 7.5 Hz/1.5 Hz, 1H, H-4 phenyl), 7.12 (s, 1H,
H-2 phenyl), 7.18 (dd, J = 7.5/1.5 Hz, 1H, H-6 phenyl),
123

Med Chem Res (2012) 21:1953–1966
1961
7.26 (t, J = 7.5 Hz, 1H, H-5 phenyl), 7.46 (d, J = 15.5 Hz,
1H, H-a), 7.48 (d, J = 3.0 Hz, 1H, H-3 furanyl), 7.71 (d,
J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz, CD3OD): d
12.7, 109.3, 114.7, 117.8, 120.1, 121.1, 121.2, 129.9, 136.2,
143.8, 152.4, 157.9, 159.5, 177.8; EIMS m/z (rel. int.) calcd
for C14H12O3 (M?, %): 228 (M?, 32).
1-(5-methylfuran-2-yl)-3-(2,4,6-trimethoxyphenyl)prop-
2-en-1-one (2g); Yield: 65%; yellow crystals; IR(KBr)
m
max: 2941 (C–H stretch), 1645 (C=O), 1588 (C=C), 1514
1
(C=C), 1321, 1206 (C–O aromatic), 1121, 755; H NMR
(500 MHz, DMSO): d 2.39 (s, 3H, CH3), 3.85 (s, 3H,
OMe), 3.91 (s, 6H, OMe), 6.30 (s, 2H, H-3/5 phenyl), 6.38
(d, J = 3.0 Hz, 1H, H-4 furanyl), 7.37 (d, J = 3.0 Hz, 1H,
H-3 furanyl), 7.65 (d, J = 16.0 Hz, 1H, H-a), 8.05 (d,
J = 16.0 Hz, 1H, H-b). 13C NMR (125 MHz, DMSO): d
14.4, 56.2, 56.7, 91.6, 105.6, 109.9, 119.9, 120.9, 134.0,
153.1, 158.1, 162.0, 163.9, 178.0; EIMS m/z (rel. int.) calcd
for C17H18O5 (M?, %): 302 (M?, 5).
3-(4-hydroxyphenyl)-1-(5-methylfuran-2-yl)prop-2-en-
:
1-one (2c); Yield: 68%; yellow amorphous; IR(KBr) mmax
3402 (O–H), 2956 (C–H stretch), 1676 (C=O), 1601
(C=C), 1520 (C=C), 1162, 833; 1H NMR (500 MHz,
DMSO): d 2.31 (s, 3H, CH3), 6.40 (d, J = 3.0 Hz, 1H, H-4
furanyl), 6.84 (d, J = 8.5 Hz, 2H, H-3 phenyl), 7.44 (d,
J = 15.5 Hz, 1H, H-a), 7.60 (d, J = 15.5 Hz, 1H, H-b),
7.64 (d, J = 3.0 Hz, 1H, H-3 furanyl), 7.68 (d, J = 8.5 Hz,
2H, H-2 phenyl). 13C NMR (125 MHz, DMSO): d 14.4,
110.1, 116.5, 119.2, 121.2, 126.3, 131.5, 143.3, 152.8,
158.7, 160.7, 176.7; EIMS m/z (rel. int.) calcd for
C14H12O3 (M?, %): 228 (M?, 31).
1-(5-methylfuran-2-yl)-3-(2,3,4-trimethoxyphenyl)prop-
2-en-1-one (2h); Yield: 75%; yellow powder; IR(KBr)
m
max: 2939 (C–H stretch), 1651 (C=O), 1588 (C=C), 1514
(C=C), 1280 (C–O aromatic), 1096, 796; 1H NMR
(500 MHz, DMSO): d 2.40 (s, 3H, CH3), 3.79 (s, 3H,
OMe), 3.86 (s, 3H, OMe), 3.91 (s, 3H, OMe), 6.41 (d,
J = 3.0 Hz, 1H, H-4 furanyl), 6.91 (d, J = 9.0 Hz, 1H H-5
phenyl), 7.54 (d, J = 16.0 Hz, 1H, H-a), 7.65 (d,
J = 3.0 Hz, 1H, H-3 furanyl), 7.69 (d, J = 9.0 Hz, 1H,
H-6 phenyl), 7.86 (d, J = 16.0 Hz, 1H, H-b). 13C NMR
(125 MHz, DMSO): d 14.4, 56.6, 61.0, 62.2, 109.1, 110.2,
121.1, 121.5, 124.0, 137.2, 142.5, 153.7, 156.3, 158.9,
176.7; EIMS m/z (rel. int.) calcd for C17H18O5 (M?, %):
302 (M?, 12).
3-(2,5-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-
2-en-1-one (2d) Yield: 69%; yellow crystals; IR(KBr) mmax
2945 (C–H stretch), 1652 (C=O), 1597 (C=C), 1514 (C=C),
:
1
1067, 802; H NMR (500 MHz, DMSO): d 2.39 (s, 3H,
CH3), 3.78 (s, 3H, OMe), 3.82 (s, 3H, OMe), 6.42 (d,
J = 3.5 Hz, 1H, H-4 furanyl), 7.01 (overlapped, 2H, H-3/4
phenyl), 7.46 (s, 1H, H-6 phenyl), 7.63 (d, J = 16.0 Hz,
1H, H-a), 7.73 (d, J = 3.5 Hz, 1H, H-3 furanyl), 7.99 (d,
J = 16.0 Hz, 1H, H-b). 13C NMR (125 MHz, DMSO): d
14.4, 56.2, 56.7, 109.9, 113.3, 113.6, 118.4, 121.9, 122.7,
124.1, 137.0, 152.7, 153.3, 153.9, 159.2, 176.6; EIMS m/z
(rel. int.) calcd for C16H16O4 (M?, %): 272 (30).
3-(2-fluoro-4-methoxyphenyl)-1-(5-methylfuran-2-yl)prop-
2-en-1-one (2i); Yield: 87%; yellow crystals; IR(KBr) mmax
:
2921 (C–H stretch), 1652 (C=O), 1597 (C=C), 1513 (C=C),
1271 (C–O aromatic), 1067; 1H NMR (500 MHz, DMSO):
d 2.40 (s, 3H, CH3), 3.82 (s, 3H), 6.42 (d, J = 3.5 Hz, 1H,
H-4 furanyl), 6.89 (d, J = 12.0 Hz, 1H, H-5 phenyl), 6.94
(d, J = 12.0 Hz, 1H, H-6 phenyl), 7.56 (d, J = 16.0 Hz,
1H, H-a), 7.67 (d, J = 3.5 Hz, 1H, H-3 furanyl), 7.73 (d,
J = 16.0 Hz, 1H, H-b), 7.96 (s, 1H, H-3 phenyl). 13C
NMR (125 MHz, DMSO): d 14.5, 56.6, 102.5, 110.1,
112.3, 115.2, 121.7, 130.7, 134.3, 152.6, 159.2, 161.7,
163.4, 162.7, 176.3; EIMS m/z (rel. int.) calcd for
C15H13FO3 (M?, %): 260 (M?, 39).
2-(2-(3-(5-methylfuran-2-yl)-3-oxoprop-1-enyl)phenoxy)
acetic acid (2e) Yield: 43%; yellow powder; IR(KBr) mmax
:
1H NMR (500 MHz, DMSO): d 2.39 (s, 3H, CH3), 4.83 (s,
2H, CH2), 6.41 (d, J = 3.5 Hz, 1H, H-4 furanyl), 7.01
(overlapped, 2H, H-3/5 phenyl), 7.40 (t, J = 8.0 Hz, 1H,
H-4 phenyl), 7.73 (overlapped, 2H, H-3 furanyl/H-6 phe-
nyl), 7.82 (d, J = 8.0 Hz, 1H, H-4 phenyl), 7.90 (d,
J = 16.0 Hz, 1H, H-b). 13C NMR (125 MHz, DMSO): d
14.3, 65.6, 109.9, 110.1, 113.3, 121.8, 123.5, 123.7, 130.8,
132.4, 138.0, 152.8, 157.5, 159.2, 170.7, 176.9; EIMS m/z
(rel. int.) calcd for C16H14O5 (M?, %): 211 (M?, 100).
1-(5-methylfuran-2-yl)-3-(4-nitrophenyl)prop-2-en-1-
one (2f); Yield: 85%; orange crystals; IR(KBr) mmax: 2922
(C–H stretch), 1640 (C=O), 1520 (C=C), 1340 (N–O),
3-(2,3-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-
2-en-1-one (2j); Yield: 76%; yellow crystals; IR(KBr) mmax
:
2934 (C–H stretch), 1651 (C=O), 1596 (C=C), 1512 (C=C),
1267 (C–O aromatic), 1075, 999; 1H NMR (500 MHz,
DMSO): d 2.40 (s, 3H, CH3), 3.79 (s, 3H, OMe), 3.83 (s,
3H, OMe), 6.43 (d, J = 3.0 Hz, 1H, H-4 furanyl), 7.14
(overlapped, 2H, H-4/6 phenyl), 7.54 (t, J = 4.5 Hz, 1H,
H-5 phenyl), 7.62 (d, J = 16.5 Hz, 1H, H-a), 7.72 (d,
J = 3.0 Hz, 1H, H-3 furanyl), 7.95 (d, J = 16.5 Hz, 1H,
H-b). 13C NMR (125 MHz, DMSO): d 14.4, 56.5, 61.7,
110.3, 115.6, 119.7, 122.1, 123.6, 124.9, 128.7, 136.8,
148.9, 152.6, 153.5, 159.3, 176.6; EIMS m/z (rel. int.) calcd
for C16H16O4 (M?, %): 272 (M?, 5).
1
1053, 1011; H NMR (500 MHz, DMSO): d 2.39 (s, 3H,
CH3), 6.39 (d, J = 3.5 Hz, 1H, H-4 furanyl), 6.74 (d,
J = 8.5 Hz, 2H, H-2/6 phenyl), 7.36 (d, J = 15.5 Hz, 1H,
H-a), 7.59 (overlapped, 3H, H-3 furanyl/H-3/4 phenyl),
7.64 (d, J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz,
DMSO): d 14.3, 109.9, 112.4, 116.8, 120.4, 122.5, 131.2,
143.9, 152.6, 153.0, 158.2, 176.7; EIMS m/z (rel. int.)
C14H11NO4 (M?, %): 257 (M?, 100).
123

1962
Med Chem Res (2012) 21:1953–1966
3-(2,6-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-
2-en-1-one (2k) Yield: 82%; yellow needles; IR(KBr) mmax
2942 (C–H stretch), 1649 (C=O), 1592 (C=C), 1513 (C=C),
(C–H stretch), 1653 (C=O), 1600 (C=C), 1508 (C=C), 1335
1
(C–O aromatic), 1072, 760; H NMR (500 MHz, DMSO):
:
d 2.40 (s, 3H, CH3), 6.45 (d, J = 3.5 Hz, 1H, H-4 furanyl),
7.45 (overlapped, 2H H-4/5 phenyl), 7.55 (d, J = 8.0 Hz,
1H H-6 phenyl), 7.70 (d, J = 15.5 Hz, 1H, H-a), 7.78 (d,
J = 3.0 Hz, 1H, H-3 furanyl), 7.99 (d, J = 15.5 Hz, 1H,
H-b), 8.12 (d, J = 8.0 Hz, 1H, H-3 phenyl). 13C NMR
(125 MHz, DMSO): d 14.4, 110.3, 122.9, 125.4, 128.4,
129.0, 130.7, 132.6, 132.8, 134.9, 137.4, 152.4, 159.8,
176.0; EIMS m/z (rel. int.) calcd for C14H11ClO2 (M?, %):
246 (M?, 8).
1
1260 (C–O aromatic), 1203 (C–O), 1108, 742; H NMR
(500 MHz, DMSO): d 2.40 (s, 3H, CH3), 3.90 (s, 6H,
OMe), 6.40 (d, J = 3.0 Hz, 1H, H-4 furanyl), 6.74 (d,
J = 8.0 Hz, 2H, H-3/5 phenyl), 7.39 (t, J = 8.0 Hz, 1H,
H-4 phenyl), 7.44 (d, J = 3.0 Hz, 1H, H-3 furanyl), 7.79
(d, J = 16.0 Hz, 1H, H-a), 8.09 (d, J = 16.0 Hz, 1H, H-b).
13C NMR (125 MHz, DMSO): d 14.4, 56.7, 104.8, 110.1,
112.0, 120.7, 124.1, 132.9, 133.7, 152.9, 158.6, 160.7,
177.9; EIMS m/z (rel. int.) calcd for C14H12O3 (M?, %):
272 (M?, 4).
3-(3-chlorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2p) Yield: 77%; yellow powder; IR(KBr) mmax: 2930
(C–H stretch), 1656 (C=O), 1602 (C=C), 1512 (C=C), 1205
(C–O aromatic), 1066; 1H NMR (500 MHz, DMSO): d
2.40 (s, 3H, CH3), 6.44 (d, J = 3.0 Hz, 1H, H-4 furanyl),
7.47 (overlapped, 2H, H-4/5 phenyl), 7.64 (d, J = 15.5 Hz,
1H, H-a), 7.70 (d, J = 15.5 Hz, 1H, H-b), 7.81 (over-
lapped, 2H, H-3 furanyl/H-6 phenyl), 7.98 (s, 1H, H-2
phenyl).13C NMR (125 MHz, DMSO): d 14.5, 110.3,
122.7, 124.3, 128.3, 128.5, 130.7, 131.4, 134.5, 137.5,
141.1, 152.5, 159.6, 176.2; EIMS m/z (rel. int.) calcd for
C14H11ClO2 (M?, %): 246 (M?, 99).
3-(2-fluorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2l); Yield: 84%; pale yellow powder; IR(KBr) mmax
:
3111 (C–H stretch), 1660 (C=O), 1604 (C=C), 1513 (C=C),
1228 (C–O aromatic), 757; 1H NMR (500 MHz, DMSO): d
2.40 (s, 3H, CH3), 6.43 (d, J = 3.0 Hz, 1H, H-4 furanyl),
7.29 (d, J = 8.0 Hz, 1H, H-3 phenyl), 7.30 (d, J = 8.0 Hz,
1H, H-6 phenyl), 7.49 (t, J = 8.0 Hz, 1H, H-5 phenyl),
7.70 (d, J = 15.5 Hz, 1H, H-a), 7.72 (d, J = 3.0 Hz, 1H,
H-3 furanyl), 7.79 (d, J = 15.5 Hz, 1H, H-b), 8.03 (t,
J = 8.0 Hz, 1H, H-4 phenyl). 13C NMR (125 MHz,
DMSO): d 14.4, 110.4, 116.7, 122.4, 122.8, 124.8, 125.6,
129.7, 133.2, 134.1, 152.4, 159.6, 160.5, 176.1; EIMS m/z
(rel. int.) calcd for C14H11FO2 (M?, %): 230 (M?, 100).
3-(3-fluorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2m); Yield: 91%; yellow crystals; IR(KBr) mmax: 3104
(C–H stretch), 1654 (C=O), 1606 (C=C), 1513 (C=C), 1266
3-(4-chlorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2q) Yield: 89%; pale yellow powder; IR(KBr) mmax
:
3011 (C–H stretch), 1650 (C=O), 1596 (C=C), 1508 (C=C),
1333 (C–O aromatic), 1065, 776; 1H NMR (500 MHz,
DMSO): d 2.40 (s, 3H, CH3), 6.44 (d, J = 3.5 Hz, 1H, H-4
furanyl), 7.51 (d, J = 8.5 Hz, 2H, H-3/5 phenyl), 7.66 (d,
J = 15.5 Hz, 1H, H-a), 7.68 (d, J = 15.5 Hz, 1H, H-b),
7.76 (d, J = 3.5 Hz, 1H, H-3 furanyl), 7.87 (d, J = 8.5 Hz,
2H, H-2/6 phenyl). 13C NMR (125 MHz, DMSO): d 14.5,
110.2, 122.3, 123.5, 129.6, 131.0, 134.2, 135.6, 141.4,
152.5, 159.4, 176.3; EIMS m/z (rel. int.) calcd for
C14H11ClO2 (M?, %): 246 (12).
1
(C–O aromatic), 1068, 784; H NMR (500 MHz, DMSO):
d 2.40 (s, 3H, CH3), 6.43 (d, J = 3.5 Hz, 1H, H-4 furanyl),
7.26 (t, J = 8.5 Hz, 1H, H-5 phenyl), 7.49 (d, J = 8.5 Hz,
1H, H-4 phenyl), 7.64 (d, J = 8.5 Hz, 1H, H-5 phenyl),
7.67 (s, 1H, H-2 phenyl), 7.69 (d, J = 15.5 Hz, 1H, H-a),
7.77 (d, J = 15.5 Hz, 1H, H-b), 7.79 (d, J = 3.5 Hz, 1H,
H-3 furanyl). 13C NMR (125 MHz, DMSO): d 14.5, 110.3,
115.2, 117.8, 122.5, 124.2, 126.1, 131.4, 137.9, 141.3,
152.5, 159.5, 164.2, 176.2; EIMS m/z (rel. int.) calcd for
C14H11FO2 (M?, %): 230 (M?, 68).
3-(furan-2-yl)-1-(5-methylfuran-2-yl)prop-2-en-1-one
(2r) Yield: 66%; brown crystals; IR(KBr) mmax: 2931 (C–H
stretch), 1654 (C=O), 1514 (C=C), 1064, 1018; H NMR
1
(500 MHz, DMSO): d 2.40 (s, 3H, CH3), 6.41 (d,
J = 3.0 Hz, 1H, H-4 furanyl), 6.67 (d, J = 1.5 Hz, 1H,
H-3’ furanyl), 7.04 (d, J = 3.0 Hz, 1H, H-5’ furanyl), 7.30
(d, J = 15.5 Hz, 1H, H-a), 7.53 (d, J = 15.5 Hz, 1H, H-b),
7.58 (dd, J = 3.0 Hz/1.5 Hz, 1H, H-4’ furanyl), 7.88 (d,
J = 3.0 Hz, 1H, H-3 furanyl). 13C NMR (125 MHz,
DMSO): d 14.4, 110.3, 113.8, 117.5, 119.4, 121.4, 129.5,
146.7, 151.7, 152.5, 159.1, 176.2; EIMS m/z (rel. int.) calcd
for C12H10O3 (M?, %): 202 (M?, 100).
3-(4-fluorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2n) Yield: 72%; pale yellow powder; IR(KBr) mmax
:
3017 (C–H stretch), 1650 (C=O), 1595 (C=C), 1511 (C=C),
1336 (C–O aromatic), 1067, 831; 1H NMR (500 MHz,
DMSO): d 2.40 (s, 3H, CH3), 6.44 (d, J = 3.0 Hz, 1H, H-4
furanyl), 7.31 (d, J = 8.5 Hz, 2H, H-3/5 phenyl), 7.62 (d,
J = 15.5 Hz, 1H, H-a), 7.71 (d, J = 15.5 Hz, 1H, H-b),
7.75 (d, J = 3.0 Hz, 1H, H-3 furanyl), 7.93 (d, J = 8.5 Hz,
2H, H-2/6 phenyl). 13C NMR (125 MHz, DMSO): d 14.4,
110.2, 116.5, 122.2, 122.6, 131.8, 141.6, 152.6, 159.3,
163.0, 165.0, 176.4; EIMS m/z (rel. int.) calcd for
C14H11FO2 (M?, %): 230 (67).
1-(2,5-dimethylfuran-3-yl)-3-(2-hydroxyphenyl)prop-
2-en-1-one (3a) Yield: 32%; yellow crystals; IR(KBr) mmax
:
3306 (–OH), 1642 (C=O), 1576 (C=C), 1458 (C=C), 1229
(C–O aromatic), 1017, 755; 1H NMR (500 MHz, CD3OD):
d 2.27 (s, 3H, CH3), 2.56 (s, 3H, CH3), 6.43 (s, 1H, H-4
furanyl), 6.87 (overlapped, 2H, H-3/5 phenyl),), 7.24
3-(2-chlorophenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-
one (2o) Yield: 80%; pale yellow; IR(KBr) mmax: 3017
123

Med Chem Res (2012) 21:1953–1966
1963
(t, J = 8.0 Hz, 1H, H-4 phenyl),), 7.45 (d, J = 15.5 Hz,
1H, H-a), 7.59 (d, J = 8.0 Hz, 1H, H-6 phenyl), 8.00 (d,
J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz, CD3OD): d
11.9, 13.4, 105.7, 115.9, 119.7, 121.9, 122.9, 123.8, 129.3,
131.6, 139.5, 150.5, 157.6, 157.8, 187.8; EIMS m/z (rel.
int.) calcd for C15H14O3 (M?, %): 242 (M?, 26).
CD3OD): d 116.0, 119.7, 120.1, 122.2, 122.8, 127.1, 128.8,
132.1, 137.6, 141.1, 148.9, 154.5, 157.8, 190.3; EIMS m/z
(rel. int.) calcd for C14H11NO2 (M?, %): 225 (M?, 15).
3-(3-hydroxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one
(4b) Yield: 62%; pale green powder; IR(KBr) mmax: 3326
(–OH), 1667 (C=O), 1581 (C=C), 1451, 1243 (C–O aro-
1
1-(2,5-dimethylfuran-3-yl)-3-(3-hydroxyphenyl)prop-2-
matic), 778; H NMR (500 MHz, CD3OD): d 6.87 (dd,
en-1-one (3b) Yield: 84%; yellow crystals; IR(KBr) mmax
:
J = 7.5 Hz/1.5 Hz, 1H, H-4 phenyl), 7.15 (s, 1H, H-2
phenyl), 7.20 (d, J = 7.5 Hz, 1H, H-6 phenyl), 7.27 (t,
J = 7.5 Hz, 1H, H-5 phenyl), 7.61 (td, J = 7.5 Hz/1.5 Hz,
1H, H-5 pyridinyl), 7.81 (d, J = 16.0 Hz, 1H, H-a), 7.98
(td, J = 7.5 Hz/1.5 Hz, 1H, H-4 pyridinyl), 8.14 (d,
J = 7.5 Hz, 1H, H-3 pyridinyl), 8.20 (d, J = 16.0 Hz, 1H,
3392 (–OH), 1651 (C=O), 1583 (C=C), 1452 (C=C), 1399,
1231 (C–O aromatic), 1019, 783; 1H NMR (500 MHz,
CD3OD): d 2.27 (s, 3H, CH3), 2.52 (s, 3H, CH3), 6.41 (s,
1H, H-4 furanyl), 6.85 (dd, J = 8.0 Hz/1.5 Hz, 1H, H-5
phenyl), 7.17 (overlapped, 2H, H-2/4 phenyl), 7.18 (d,
J = 16.0 Hz, 1H, H-a), 7.25 (d, J = 8.0 Hz, 1H, H-6
phenyl), 7.56 (d, J = 16.0 Hz, 1H, H-b). 13C NMR
(125 MHz, CD3OD): d 11.9, 13.4, 105.6, 114.6, 117.6,
119.9, 123.8, 129.9, 136.3, 143.3, 150.5, 157.9, 158.2,
186.8, 193.0; EIMS m/z (rel. int.) calcd for C15H14O3 (M?,
%): 242 (M?, 100).
H-b), 8.73 (dd, J = 7.5 Hz/1.5 Hz, 1H, H-6 pyridinyl). 13
C
NMR (125 MHz, CD3OD): d 114.7, 118.0, 120.3, 120.7,
122.8, 127.3, 129.9, 136.5, 137.6, 145.1, 149.0, 154.2,
158.0, 199.7; EIMS m/z (rel. int.) calcd for C14H11NO2
(M?, %): 225 (M?, 25).
3-(2-hydroxyphenyl)-1-(pyridin-4-yl)prop-2-en-1-one
(5a) Yield: 31%; yellow crystals; IR(KBr) mmax: 3273
(–OH), 1642 (C=O), 1586 (C=C), 1458, 1251 (C–O aro-
matic), 753; 1H NMR (500 MHz, CD3OD): d 6.90 (d,
J = 8.0 Hz, 1H, H-3 phenyl), 7.29 (t, J = 8.0 Hz, 1H, H-5
phenyl), 7.70 (d, J = 8.0 Hz, 1H, H-6 phenyl), 7.75 (d,
J = 16.0 Hz, 1H, H-a), 7.88 (t, J = 8.0 Hz, 1H, H-4
phenyl), 7.93 (d, J = 6.0 Hz, 2H, H-3/5 pyridinyl), 8.17 (d,
J = 16.0 Hz, 1H, H-b), 8.78 (d, J = 6.0 Hz, 2H, H-2/6
pyridinyl). 13C NMR (125 MHz, CD3OD): d 116.0, 119.8,
120.8, 122.1, 123.0, 129.5, 132.5, 143.3, 150.1, 150.2,
163.9, 189.2; EIMS m/z (rel. int.) calcd for C14H11NO2
(M?, %): 224 (M?, 13).
1-(2,5-dimethylfuran-3-yl)-3-(4-hydroxyphenyl)prop-2-
en-1-one (3c); Yield: 54%; yellow powder; IR(KBr) mmax
:
3216 (–OH), 1675 (C=O), 1606 (C=C), 1454 (C=C), 1292,
1219 (C–O aromatic), 1163, 833; 1H NMR (500 MHz,
CD3OD): d 2.29 (s, 3H, CH3), 2.57 (s, 3H, CH3), 6.51 (s,
1H, H-4 furanyl), 7.21 (d, J = 15.5 Hz, 1H, H-a), 7.58 (d,
J = 9.0 Hz, 2H, H-3/5 phenyl), 7.65 (d, J = 15.5 Hz, 1H,
H-b), 7.80 (d, J = 9.0 Hz, 2H, H-2/6 phenyl). 13C NMR
(125 MHz, CD3OD): d 11.9, 13.4, 105.6, 115.7, 120.7,
122.7, 126.5, 130.4, 132.3, 143.8, 150.5, 160.4, 191.7;
EIMS m/z (rel. int.) calcd for C15H14O3 (M?, %): 242 (M?,
100).
2-(2-(3-(2,5-dimethylfuran-3-yl)-3-oxoprop-1-enyl)phenoxy)
3-(3-hydroxyphenyl)-1-(pyridin-4-yl)prop-2-en-1-one
(5b) Yield: 42%; pale yellow powder; IR(KBr) mmax: 3436
(–OH), 1631 (C=O), 1580 (C=C), 1414, 1240 (C–O aro-
matic), 786; 1H NMR (500 MHz, CD3OD): d 6.91 (d,
J = 8.0 Hz, 1H, H-4 phenyl), 7.16 (s, 1H, H-2 phenyl),
7.24 (d, J = 8.0 Hz, 1H, H-6 phenyl), 7.28 (t, J = 8.0 Hz,
1H, H-5 phenyl), 7.61 (d, J = 16.0 Hz, 1H, H-a), 7.77 (d,
J = 16.0 Hz, 1H, H-b), 7.95 (d, J = 6.0 Hz, 2H, H-3/5
pyridinyl), 8.78 (d, J = 6.0 Hz, 2H, H-2/6 pyridinyl). 13C
NMR (125 MHz, CD3OD): d 114.9, 118.3, 120.4, 121.0,
122.1, 129.9, 135.9, 145.3, 147.1, 150.2, 158.0, 189.9;
EIMS m/z (rel. int.) calcd for C14H11NO2 (M?, %): 225
(M?, 55).
acetic acid (3d) Yield: 42%; yellow powder; IR(KBr) mmax
:
1H NMR (500 MHz, DMSO): d 2.25 (s, 3H, CH3), 2.25 (s,
3H, CH3), 4.81 (s, 2H, CH2), 6.75 (s, 1H, H-4 furanyl),
7.00 (overlapped, 2H, H-3/5 phenyl), 7.39 (t, J = 8.0 Hz,
1H, H-4 phenyl), 7.68 (d, J = 15.5 Hz, 1H, H-a), 7.80 (d,
J = 8.0 Hz, 1H, H-6 phenyl), 7.87 (d, J = 15.5 Hz, 1H,
H-b). 13C NMR (125 MHz, DMSO): d 13.6, 14.7, 65.6,
106.8, 113.2, 121.8, 123.1, 123.8, 125.8, 130.7, 132.3,
138.2, 150.4, 157.5, 157.7, 170.7, 185.9; EIMS m/z (rel.
int.) calcd for C17716O5 (M?, %): 300 (M?, 48).
3-(2-hydroxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one
(4a); Yield: 32%; green crystals; IR(KBr) mmax: 3401
(–OH), 1660 (C=O), 1592 (C=C), 1458, 1339, 746; 1H
NMR (500 MHz, CD3OD): d 6.88 (dd, J = 8.0 Hz/1.5 Hz,
1H, H-3 phenyl), 6.90 (t, J = 8.0 Hz, 1H, H-5 phenyl),
7.26 (td, J = 8.0 Hz/1.5 Hz, 1H, H-4 phenyl), 7.59 (dd,
J = 8.0 Hz/1.5 Hz, 1H, H-6 phenyl), 7.70 (d,
J = 15.0 Hz, 1H, H-a), 8.00 (td, J = 8.0 Hz/1.5 Hz, 1H,
H-5 pyridinyl), 8.14 (d, J = 15.0 Hz, 1H, H-b), 8.27
(overlapped, 2H, H-3/4 pyridinyl), 8.74 (dd, J = 8.0 Hz/
1.5 Hz, 1H, H-6 pyridinyl). 13C NMR (125 MHz,
3-(4-hydroxyphenyl)-1-(pyridin-4-yl)prop-2-en-1-one
(5c) Yield: 61%; orange powder; IR(KBr) mmax: 3286
(–OH), 1632 (C=O), 1573 (C=C), 1456, 1252 (C–O aro-
matic), 782; 1H NMR (500 MHz, CD3OD): d 6.87 (d,
J = 8.5 Hz, 2H, H-5/5 phenyl), 7.60 (d, J = 15.5 Hz, 1H,
H-a), 7.72 (d, J = 8.5 Hz, 2H, H-2/6 phenyl), 7.92 (d,
J = 15.5 Hz, 1H, H-b), 8.58 (d, J = 7.0 Hz, 2H, H-3/5
pyridinyl), 9.09 (d, J = 7.0 Hz, 2H, H-2/6 pyridinyl). 13C
NMR (125 MHz, CD3OD): d 115.8, 117.4, 122.7, 127.1,
123

1964
Med Chem Res (2012) 21:1953–1966
130.8, 137.6, 145.7, 148.9, 160.7, 189.7; EIMS m/z (rel.
int.) calcd for C14H11NO2 (M?, %): 225 (M?, 100).
3-(2-hydroxyphenyl)-1-(thiophen-2-yl)prop-2-en-1-one
(6a) Yield: 25%; yellow solid; IR(KBr) mmax: 3293 (–OH),
1636 (C=O), 1570 (C=C), 1412, 1234 (C–O aromatic),
121.7, 128.1, 128.3, 129.4, 132.1, 132.3, 139.2, 140.9,
144.9, 157.9, 182.6; EIMS m/z (rel. int.) calcd for
C13H9ClO2S (M?, %): 264 (M?, 12).
1-(5-chlorothiophen-2-yl)-3-(3-hydroxyphenyl)prop-2-
en-1-one (7b) Yield: 56%; pale yellow solid; IR(KBr) mmax
:
1
1063, 752; H NMR (500 MHz, CD3OD): d 6.89 (over-
3370 (–OH), 1641 (C=O), 1582 (C=C), 1416, 1262 (C–O
aromatic), 1022; 1H NMR (500 MHz, CD3OD): d 6.89 (dd,
J = 8.0 Hz/1.0 Hz, 1H, H-4 phenyl), 7.12 (s, 1H, H-2
phenyl) 7.14 (d, J = 4.0 Hz, 1H, H-4 thiophenyl), 7.22
(dd, J = 8.0 Hz/1.0 Hz, 1H, H-6 phenyl), 7.27 (t,
J = 8.0 Hz, 1H, H-5 phenyl), 7.55 (d, J = 15.5 Hz, 1H,
H-a), 7.72 (d, J = 15.5 Hz, 1H, H-b), 7.93 (d, J = 4.0 Hz,
1H, H-3 thiophenyl). 13C NMR (125 MHz, CD3OD): d
114.8, 118.0, 120.1, 120.2, 128.4, 129.9, 132.8, 136.1,
139.6, 144.6, 144.8, 157.9, 181.9; EIMS m/z (rel. int.) calcd
for C13H9ClO2S (M?, %): 264 (M?, 50).
lapped, 2H, H-3/5 phenyl), 7.25 (overlapped, 2H, H-4
thiophenyl/H-4 phenyl), 7.67 (d, J = 8.0 Hz, 1H, H-6
phenyl), 7.76 (d, J = 15.5 Hz, 1H, H-a), 7.86 (dd,
J = 4.5 Hz/1.5 Hz, 1H, H-3 thiophenyl), 8.02 (dd,
J = 4.5 Hz/1.5 Hz, 1H, H-5 thiophenyl), 8.15 (d,
J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz, CD3OD): d
115.9, 119.7, 121.1, 121.8, 129.4, 131.4, 131.9, 132.6,
134.4, 140.5, 145.7, 157.8, 183.7; EIMS m/z (rel. int.) calcd
for C13H10O2S (M?, %): 230 (M?, 14).
3-(4-hydroxyphenyl)-1-(thiophen-2-yl)prop-2-en-1-one
(6b) Yield: 71%; yellow powder; IR(KBr) mmax: 3171
(–OH), 1671 (C=O), 1605 (C=C), 1454 (C=C), 1290 (C–O
1-(5-chlorothiophen-2-yl)-3-(4-hydroxyphenyl)prop-2-
en-1-one (7c) Yield: 71%; yellow powder; IR(KBr) mmax
3369 (–OH), 1676 (C=O), 1582 (C=C), 1416, 1217 (C–O
:
1
aromatic), 1219 (C–O), 1163, 833; H NMR (500 MHz,
1
CD3OD): d 6.86 (d, J = 8.5 Hz, 2H, H-3/5 phenyl), 7.25
(t, J = 4.0 Hz, 1H, H-4 thiophenyl), 7.50 (d, J = 15.5 Hz,
1H, H-a), 7.61 (d, J = 8.5 Hz, 2H, H-2/6 phenyl), 7.76 (d,
J = 15.5 Hz, 1H, H-b), 7.84 (dd, J = 4.0 Hz/1.5 Hz, 1H,
H-3 thiophenyl), 8.05 (dd, J = 4.0 Hz/1.5 Hz, 1H, H-5
thiophenyl). 13C NMR (125 MHz, CD3OD): d 115.8,
118.1, 126.4, 128.5, 130.8, 132.6, 134.3, 144.8, 145.8,
160.6, 183.2; EIMS m/z (rel. int.) calcd for C15H14O3S
(M?, %): 230 (M?, 100).
aromatic), 1157; H NMR (500 MHz, CD3OD): d 6.85 (d,
J = 8.0 Hz, 2H, H-3/5 phenyl), 7.11 (d, J = 4.0 Hz, 1H,
H-4 thiophenyl), 7.43 (d, J = 15.5 Hz, 1H, H-a), 7.61 (d,
J = 8.0 Hz, 2H, H-2/6 phenyl), 7.74 (d, J = 15.5 Hz, 1H,
H-b), 7.88 (d, J = 4.0 Hz, 1H, H-3 thiophenyl). 13C NMR
(125 MHz, CD3OD): d 115.8, 116.7, 126.3, 128.2, 130.8,
132.2, 139.1, 144.9, 145.0, 160.8, 182.1; EIMS m/z (rel.
int.) calcd for C13H9ClO2S (M?, %): 264 (M?, 100).
1-(5-chlorothiophen-2-yl)-3-(2,5-dimethoxyphenyl)prop-
3-(2,5-dimethoxyphenyl)-1-(thiophen-2-yl)prop-2-en-1-
one (6c) Yield: 71%; yellow crystals; IR(KBr) mmax: 2942
(C–H stretch), 1647 (C=O), 1589 (C=C), 1495 (C=C),
2-en-1-one (7d) Yield: 63%; yellow powder; IR(KBr) mmax:
2923 (C–H stretch), 1676 (C=O), 1614 (C=C), 1511 (C=C),
1225 (C–O aromatic), 1074; 1H NMR (500 MHz, DMSO):
d 3.79 (s, 3H, CH3), 3.83 (s, 3H, CH3), 7.04 (overlapped,
2H, H-3/4 phenyl), 7.37 (d, J = 4.0 Hz, 1H, H-4 thio-
phenyl), 7.54 (s, 1H, H-6 phenyl), 7.80 (d, J = 15.5 Hz,
1H, H-a), 7.90 (d, J = 15.5 Hz, 1H, H-b), 8.24 (d,
J = 4.0 Hz, 1H, H-3 thiophenyl). 13C NMR (125 MHz,
DMSO): d 56.5, 56.9, 113.3, 113.8, 119.2, 121.2, 123.8,
129.7, 129.9, 134.4, 138.6, 145.4, 153.5, 153.9, 181.7;
EIMS m/z (rel. int.) calcd for C15H13ClO3S (M?, %): 308
(M?, 11).
1
1414, 1258 (C–O aromatic), 1219 (C–O), 1044; H NMR
(500 MHz, CDCl3): d 3.79 (s, 3H, OMe), 3.85 (s, 3H,
OMe), 6.86 (d, J = 9.0 Hz, 1H, H-4 phenyl), 6.93 (d,
J = 9.0 Hz, 1H, H-3 phenyl), 7.14 (s, 1H, H-6 phenyl),
7.16 (t, J = 4.0 Hz, 1H, H-4 thiophenyl), 7.51 (d,
J = 15.5 Hz, 1H, H-a), 7.65 (d, J = 4.0 Hz, 1H, H-3
thiophenyl), 7.84 (d, J = 4.0 Hz, 1H, H-5 thiophenyl),
8.11 (d, J = 15.5 Hz, 1H, H-b). 13C NMR (125 MHz,
CDCl3): d 56.0, 56.4, 112.7, 114.2, 117.4, 122.9, 124.5,
128.4, 131.9, 133.8, 139.6, 146.0, 153.6, 153.7, 182.8;
EIMS m/z (rel. int.) calcd for C15H14O3S (M?, %): 274
(M?, 10).
Bioassay procedures
1-(5-chlorothiophen-2-yl)-3-(2-hydroxyphenyl)prop-2-
en-1-one (7a) Yield: 51%; yellow needle crystals; IR(KBr)
Cell cultures and treatment
m
max: 3258 (–OH), 1629 (C=O), 1565 (C=C), 1415, 1231
(C–O aromatic), 1021, 744; 1H NMR (500 MHz, CD3OD):
6.89 (overlapped, 2H, H-3/5 phenyl), 7.14 (d,
The RAW 264.7 cells (ATCC) were cultured in a plastic
culture flask in Dulbecco’s Modified Eagle’s Medium
(DMEM) supplemented with 10% FBS and 1% penicillin/
streptomycin under 5% CO2 atmosphere at 37°C. Cells at
confluency of 80–90% were scrapped out and seeded into
96-well plate at 5 9 104 cells/50 ll well. Attached cells
were then induced with 100 U/ml of recombinant mouse
d
J = 4.0 Hz, 1H, H-4 thiophenyl), 7.28 (td, J = 8.0 Hz/
2.0 Hz, 1H, H-4 phenyl), 7.67 (d, J = 15.5 Hz, 1H, H-a),
7.68 (dd, J = 8.5 Hz/2.0 Hz, 1H, H-6 phenyl), 7.87 (d,
J = 4.0 Hz, 1H, H-3 thiophenyl), 8.14 (d, J = 15.5 Hz,
1H, H-b). 13C NMR (125 MHz, CD3OD): d 115.9, 119.7,
123

Med Chem Res (2012) 21:1953–1966
1965
interferon-gamma (IFN-c) and 5 lg/ml of LPS (Esche-
richia coli, serotype 0111:B4) in the presence or absence
(negative control) of test compounds for 17–20 h. The NO
production was then determined by Griess assay, and the
percentage of the activity was calculated.
skeleton was selected as the atoms to superimpose all the
compounds using SYBYL 7.3 alignment method.
CoMFA analysis
The steric and electrostatic fields in CoMFA were calcu-
lated using sp3 carbon atom with ?1.0 charge as the probe
atom. Both field energies were truncated to 30 kcal/mol,
and the CoMFA fields generated automatically were scaled
by the CoMFA-STD method. In order to investigate the
effect of grid spacing, initially the CoMFA models were
developed at varying grid spacing values (i.e., 0.5, 1.0 and
Griess assay
The NO scavenging(Mirkov et al., 2004) and NO produc-
tion in cell culture were determined by measuring the
nitrite (NO2-) formation in the SNP solution mixtures and
supernatants of spent cell culture media, respectively, by
using Griess assay (Tsikas, 2007). In brief, 50 ll of Griess
Reagent (1% sulfanilamide and 0.1% naphtylethyenedi-
amine dihydrochloride in 2.5% H3PO4) was added to 50 ll
of SNP solution mixtures and/or cell culture supernatant.
The color density was measured at 550 nm after 10 min
incubation at room temperature.
2
˚
2.0 A), and the best q values were obtained when the grid
˚
spacing was set to 2.0 A.
Partial least squares (PLS) analysis
The PLS method was employed to set up a correlation
between the molecular fields and the pIC50 of anti inflam-
matory activities of the tested compounds. The optimal
number of components was determined using cross-vali-
dation (leave-one-out) method. To speed up the analysis
and reduce noise, columns with an r value below 2.0 kcal/
mol were filtered off. The cross-validated q2 that resulted in
optimum number of components and the lowest standard
error of prediction were taken. Final analysis was then
performed to calculate conventional r2 and standard error
using the optimum number of components.
Cell viability determination (MTT assay)
After removal of culture media, all wells were topped-up
with 100 ll of DMEM, followed by the addition of 20 ll
of
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT, 5 mg/ml). The cells were incubated under
5% CO2 at 37°C for 4 h. The formazan crystals formed
were dissolved in DMSO, the absorbance was read at
570 nm, and the percentage of cell viability was calculated.
CoMFA contour maps
Statistical analysis
Contour maps were generated as a scalar product of the
coefficients and standard deviations (StDev*Coeff) asso-
ciated with each column. Favored and disfavored levels,
fixed at 80 and 20%, respectively, were employed to dis-
play the steric fields are shown in green (more bulk
favored) and yellow (less bulk favored), while the elec-
trostatic field contours are displayed in red (electronegative
substituents favored) and blue (electropositive substituents
favored) colors.
The IC50 values were calculated using GraphPad Prism
software with one parameter model [y = 100/(1 ? a/x)].
Differences between the groups were determined by one-
way analysis of variance (ANOVA) followed by Dunnett
test method. Statistical significance of differences between
the groups was accepted at P \ 0.05.
Computational procedures
Acknowledgment This study was financially supported by a grant
from the Ministry of Higher Education, Malaysia under the Funda-
mental Research Grant Scheme (FRGS) (01-11-08-651FR). Kok-Wai
Lam was a recipient of the Graduate Research Fellowship (GRF)
scheme supported by UPM.
Molecular modeling and alignment
All molecular modeling methods were performed using
SYBYL 7.3 (Sybyl) on Genuine IntelÒ XeonÒ 2.33 GHz
Quadcore processor running under open SuSe Linux 11.0
environment. The 3D structures of all compounds were
built and minimized with conjugate gradient’s method
using SYBYL 7.3 Tripos force field with 1000 iterations.
The geometries of all molecules involved in this study were
optimized by conjugate gradient’s method using Tripos
force field. Then, the common linker of the chalcone
References
Ahmad S, Israf DA, Lajis NH, Shaari K, Mohamed H, Wahab AA,
Ariffin KT, Hoo WY, Aziz NA, Kadir AA, Sulaiman MR,
Somchit MN (2006) Cardamonin, inhibits pro-inflammatory
mediators in activated RAW 264.7 cells and whole blood. Eur J
Pharmacol 538(1–3):188–194
123

1966
Med Chem Res (2012) 21:1953–1966
Balanco JM, Pral EM, da Silva S, Bijovsky AT, Mortara RA, Alfieri
SC (1998) Axenic cultivation and partial characterization of
Leishmania braziliensis amastigote-like stages. Parasitology
116(Pt 2):103–113
Lipinski CA, Lombardo F, Dominy BW, Feeney PJ (2001) Exper-
imental and computational approaches to estimate solubility and
permeability in drug discovery and development settings. Adv
Drug Deliv Rev 46(1–3):3–26
Boeck P, Bandeira Falcao CA, Leal PC, Yunes RA, Filho VC, Torres-
Santos EC, Rossi-Bergmann B (2006) Synthesis of chalcone
analogues with increased antileishmanial activity. Bioorg Med
Chem 14(5):1538–1545
Liu X, Go ML (2007) Antiproliferative activity of chalcones with
basic functionalities. Bioorg Med Chem 15(22):7021–7034
Lopez SN, Castelli MV, Zacchino SA, Dominguez JN, Lobo G,
Charris–Charris J, Cortes JC, Ribas JC, Devia C, Rodriguez AM,
Enriz RD (2001) In vitro antifungal evaluation and structure-
activity relationships of a new series of chalcone derivatives and
synthetic analogues, with inhibitory properties against polymers
of the fungal cell wall. Bioorg Med Chem 9(8):1999–2013
Mirkov SM, Djordjevic AN, Andric NL, Andric SA, Kostic TS,
Bogdanovic GM, Vojinovic-Miloradov MB, Kovacevic RZ (2004)
Nitric oxide-scavenging activity of polyhydroxylated fullerenol,
C60(OH)24. Nitric Oxide 11(2):201–207
Phrutivorapongkul A, Lipipun V, Ruangrungsi N, Kirtikara K,
Nishikawa K, Maruyama S, Watanabe T, Ishikawa T (2003)
Studies on the chemical constituents of stem bark of Millettia
leucantha: isolation of new chalcones with cytotoxic, anti-herpes
simplex virus and anti-inflammatory activities. Chem Pharm Bull
(Tokyo) 51(2):187–190
Chen M, Christensen SB, Theander TG, Kharazmi
A (1994)
Antileishmanial activity of licochalcone A in mice infected with
Leishmania major and in hamsters infected with Leishmania
donovani. Antimicrob Agents Chemother 38(6):1339–1344
Chiaradia LD, dos Santos R, Vitor CE, Vieira AA, Leal PC, Nunes
RJ, Calixto JB, Yunes RA (2008) Synthesis and pharmacological
activity of chalcones derived from 2,4,6-trimethoxyacetophe-
none in RAW 264.7 cells stimulated by LPS: quantitative
structure-activity relationships. Bioorg Med Chem 16(2):658–
667
Cooke SA, Corlett GK, Legon AC (1998) Rotational spectrum of
thiophene? HCl. Does thiophene act as an aromatic p-type
electron donor or an n-type electron donor in hydrogen-bond
formation? J Chem Soc Faraday Trans 94(11):1565–1570
Correa R, Pereira MA, Buffon D, dos Santos L, Cechinell Filho V,
Santos AR, Nunes RJ (2001) Antinociceptive properties of
chalcones. Structure-activity relationships. Arch Pharm (Wein-
heim) 334(10):332–334
Rojas J, Dominguez JN, Charris JE, Lobo G, Paya M, Ferrandiz ML
(2002) Synthesis and inhibitory activity of dimethylamino-
chalcone derivatives on the induction of nitric oxide synthase.
Eur J Med Chem 37(8):699–705
Cramer Iii RD, Patterson DE, Bunce JD (1988) Comparative
molecular field analysis (CoMFA). 1. Effect of shape on binding
of steroids to carrier proteins. J Am Chem Soc 110(18):5959–
5967
Huang YC, Guh JH, Cheng ZJ, Chang YL, Hwang TL, Lin CN, Teng
CM (2001) Inhibitory effect of DCDC on lipopolysaccharide-
induced nitric oxide synthesis in RAW 264.7 cells. Life Sci
68(21):2435–2447
Sivakumar PM, Seenivasan SP, Kumar V, Doble M (2007) Synthesis,
antimycobacterial activity evaluation, and QSAR studies of
chalcone derivatives. Bioorg Med Chem Lett 17(6):1695–1700
Tetko IV, Gasteiger J, Todeschini R, Mauri A, Livingstone D, Ertl P,
Palyulin VA, Radchenko EV, Zefirov NS, Makarenko AS,
Tanchuk VY, Prokopenko VV (2005) Virtual computational
chemistry laboratory—design and description. J Comput Aided
Mol Des 19(6):453–463
Israf DA, Khaizurin TA, Syahida A, Lajis NH, Khozirah S (2007)
Cardamonin inhibits COX and iNOS expression via inhibition of
p65NF-jB nuclear translocation and Ij-B phosphorylation in
RAW 264.7 macrophage cells. Mol Immunol 44(5):673–679
Ko HH, Tsao LT, Yu KL, Liu CT, Wang JP, Lin CN (2003)
Structure-activity relationship studies on chalcone derivatives:
the potent inhibition of chemical mediators release. Bioorg Med
Chem 11(1):105–111
Liew CY, Tham CL, Lam KW, Mohamad AS, Kim MK, Cheah YK,
Zakaria ZA, Sulaiman MR, Lajis MN, Israf DA (2010) A
synthetic hydroxypropenone inhibits nitric oxide, prostaglandin
E2, and proinflammatory cytokine synthesis. Immunopharmacol
Immunotoxicol 32:495
Tsikas D (2007) Analysis of nitrite and nitrate in biological fluids by
assays based on the Griess reaction: appraisal of the Griess
reaction in the L-arginine/nitric oxide area of research. J Chro-
matogr B Analyt Technol Biomed Life Sci 851(1–2):51–70
Veber DF, Johnson SR, Cheng HY, Smith BR, Ward KW, Kopple KD
(2002) Molecular properties that influence the oral bioavailabil-
ity of drug candidates. J Med Chem 45(12):2615–2623
Won SJ, Liu CT, Tsao LT, Weng JR, Ko HH, Wang JP, Lin CN
(2005) Synthetic chalcones as potential anti-inflammatory and
cancer chemopreventive agents. Eur J Med Chem 40(1):103–112
Xue CX, Cui SY, Liu MC, Hu ZD, Fan BT (2004) 3D QSAR studies
on antimalarial alkoxylated and hydroxylated chalcones by
CoMFA and CoMSIA. Eur J Med Chem 39(9):745–753
123