Asymmetrical 2,6-bis(benzylidene)cyclohexanones: Synthesis, cytotoxic activity and QSAR study

Article abstract of DOI:10.1016/j.ejmech.2012.01.045

In order to develop novel anti-cancer agents, a series of asymmetrical 2,6-bis (benzylidene)cyclohexanone derivatives containing nitrobenzylidene moiety were synthesized and their cytotoxic activity were determined in vitro against MDA-MB 231, MCF-7 and SK-N-MC cell lines using MTT assay. Among the tested compounds, the highest activity against MDA-MB 231 cells was achieved by 2-(3-bromo-5-methoxy-4-propoxybenzylidene)-6-(2-nitrobenzylidene)cyclohexanone (compound 5d). Whereas, compound 5j (the 3-nitro analog of compound 5d) was the most potent compound against MCF-7 and SK-N-MC cell lines. The results indicated that the cytotoxic activity profile against different tumor cells can be optimized by desired 4-alkoxy-3-bromo-5-methoxybenzylidene scaffold.

Full text of DOI:10.1016/j.ejmech.2012.01.045

European Journal of Medicinal Chemistry 50 (2012) 113e123
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Asymmetrical 2,6-bis(benzylidene)cyclohexanones: Synthesis, cytotoxic activity
and QSAR study
,
Maryam Nakhjiri a, Maliheh Safavi b c, Eskandar Alipour d, Saeed Emami e, Amir Farzin Atash b,
,
b
Mona Jafari-Zavareh b, Sussan K. Ardestani c, Mehdi Khoshneviszadeh b, Alireza Foroumadi a
,
,
Abbas Shafiee b
*
a Drug Design & Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
b Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran14176, Iran
c Institute of Biochemistry and Biophysics, Department of Biochemistry, University of Tehran, PO Box 13145-1384, Tehran, Iran
d Department of Chemistry, Islamic Azad University, Tehran-North Branch, Zafar St., Tehran, Iran
e Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
In order to develop novel anti-cancer agents, a series of asymmetrical 2,6-bis (benzylidene)cyclohexa-
none derivatives containing nitrobenzylidene moiety were synthesized and their cytotoxic activity were
determined in vitro against MDA-MB 231, MCF-7 and SK-N-MC cell lines using MTT assay. Among the
tested compounds, the highest activity against MDA-MB 231 cells was achieved by 2-(3-bromo-5-
methoxy-4-propoxybenzylidene)-6-(2-nitrobenzylidene)cyclohexanone (compound 5d). Whereas,
compound 5j (the 3-nitro analog of compound 5d) was the most potent compound against MCF-7 and
SK-N-MC cell lines. The results indicated that the cytotoxic activity profile against different tumor cells
can be optimized by desired 4-alkoxy-3-bromo-5-methoxybenzylidene scaffold.
Received 18 September 2011
Received in revised form
23 January 2012
Accepted 23 January 2012
Available online 28 January 2012
Keywords:
Anti-Cancer agents
Cytotoxic activity
Curcuminoids
Ó 2012 Elsevier Masson SAS. All rights reserved.
Benzylidene cyclohexanone
1. Introduction
interest in the field of discovery and development of novel anti-
cancer agents with high efficacy, low toxicity, and minimum
Cancer represents one of the most serious clinical problems in
the world and its incidence is rising in developing as well as
developed countries. Despite improved imaging and molecular
diagnostic techniques and advances in prevention and chemo-
therapeutic management, the disease still impacts millions of
patients worldwide [1]. Apart from the utility of surgical operations
and irradiation, chemotherapy still remains an important option for
the management of cancer. Cancer cells are characterized by
unlimited replications, self-sufficiency in growth signals, and
insensitivity to antigrowth signals, sustained angiogenesis, metas-
tasis, and evasion of apoptosis [2]. However, anti-cancer agents
generally act on metabolically active or rapidly proliferating cells,
and cannot distinguish between cancer and normal cells. Thus,
toxicity and poor tolerance to the current anti-cancer agents are
dose-limiting factors [3]. Therefore, there has been growing
undesirable side effects.
Among the wide range of compounds tested as potential anti-
cancer agents, derivatives comprising functionalities as Michael
acceptor have attracted reasonable attention. Previous evidences
suggest that anti-cancer compounds such as alkylating agents bind
directly to various cellular nucleophiles, thus lacking selectivity.
Meanwile, Michaelacceptorscanbestructurallymodified, sothat they
can react selectively with target nucleophiles [4]. A group of repre-
sentative natural cytotoxic compounds containing Michael acceptor
are conjugated enones or enone-like compounds such as chalcones
and bis-chalcones. Chalcones are open-chain molecules where two
aromatic rings flank a three-carbon enone fragment on either side.
Curcumin (1, Fig. 1) is a naturally occurring bis-chalcone derivative
constituent of the turmeric that is obtained from the powdered root of
Curcuma longa L [5]. Previous studies have shown that curcumin has
potent anti-cancer and antiangiogenic properties [6]. Its anti-cancer
properties include growth inhibition and apoptosis induction in
a variety of cancer cell lines in vitro, as well as the ability to inhibit
tumorigenesis in vivo [7e9]. In addition, it has been proposed that
* Corresponding author. Tel.: þ98 21 66406757; fax: þ98 21 66461178.
E-mail address: ashafiee@ams.ac.ir (A. Shafiee).
0223-5234/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2012.01.045

114
M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
Fig. 1. Structures of curcumin (1) and some related compounds 2e4 as lead compounds possessing cytotoxic activity, and asymmetrical 2,6-bis(benzylidene)cyclohexanones 5 as
target compounds.
conjugated enones like curcumin, inhibit glutathione-S-transferase,
which enhances the cytotoxicity of these compounds [10,11].
In an attempt to obtain more potent curcuminoids with serving
the core structure of curcumin to keep the biological properties
and safety profile intact, biologic analyses of various synthetic
derivatives of curcumin have been conducted. These studies mainly
(nitrobenzylidene)cyclohexanones (4, Fig. 1). The highest potencies
were displayed by (2-nitrobenzylidene)cyclohexanone derivatives
[17]. They believed that interactions with cellular thiols occur at the
olefinic carbon atoms, thus the strongly electron-attracting nitro
group which should cause the olefinic carbon atoms to be electron
deficient thereby enhances thiol alkylation ability.
focused on changes in the
b
-diketone structure and aryl substitution
Considering the above results and in continuation of our research
program to find an anti-cancer agent [18e20] in this work we report
the synthesis and evaluation of a number of asymmetrical 2,6-
pattern. Therefore, some curcuminoids were made by omitting
the active methylene group and one carbonyl group of curcumin
leading to mono-carbonyl derivatives, diarylpentanoids (diaryl-1,4-
pentadiene-3-ones) [12,13]. For example, the mono-carbonyl
compounds 1,5-bis(3,4-dimethoxyphenyl)-1,4-pentadiene-3-one
(2, BDMPP), and 2,6-bis((3-methoxy-4-hydroxyphenyl)methylene)
cyclohexanone (3, BMHPC) (Fig.1), have been synthesized and tested
for antitumor activity. BMHPC has been demonstrated to have high
affinity for nuclear type II sites on breast cancer cells and inhibits cell
proliferation. In the same study, a close relative of BMHPC, 2,6-
bis((3,4-dihydroxyphenyl)methylene)cyclohexanone (BDHPC) was
shown to inhibit mouse mammary tumor growth in vivo [14].
Previously, Dimmock et al. reported the cytotoxic activity of a series
of 2,6-bis(benzylidene)cyclohexanones in which the substituents in
each of the aryl rings differed in their electronic properties [15,16]
Recently, Dimmock team also reported the synthesis and cytotoxic
activity of three series of structurally isomeric 2-benzylidene-6-
bis(benzylidene)cyclohexanones
5 containing nitrobenzylidene
moiety in order to develop novel anti-cancer agents (Fig. 1).
Different substituted-benzylidenes were considered for insertion
onto (nitrobenzylidene)cyclohexanone, including 4-hydroxyl-3-
methoxy-, 3-bromo-4-hydroxy-5-methoxy- and 3-bromo-4,5-
dimethoxybenzylidene groups due to recent disclosure of the
cytotoxicity of compounds containing these substituents. Thus we
report here, the synthesis, cytotoxic activity and SAR study of
asymmetrical 2,6-bis(benzylidene)cyclohexanones (5, Fig. 1).
2. Chemistry
The asymmetrical 2,6-bis(benzylidene)cyclohexanones 5aev
were prepared according to Scheme 1. Mono-benzylidene cyclohex-
anones 7aec were synthesized by condensation of cyclohexanone (6)

M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
115
growth inhibitory activity (IC50 ¼ 0.85e75
mg/ml) against all tested
cell lines with exception of 5q against MDA-MB-231 cells
(IC50 > 100 g/ml). In the case of MCF-7 cells, the IC50 values of
compounds were <30 g/ml, but most of compounds inhibited
these cells at the concentrations less than 10 g/ml. Compounds 5j
and 5v were the most potent compounds against MCF-7 cells with
IC50 value of z1 g/ml. Against SK-N-MC, the IC50 values of all
compounds (with the exception of compound 5a) were less than
50 g/ml and compound 5j showed the highest cytotoxic activity
with IC50 value of 1.51 ꢁ 0.70 g/ml. Furthermore, compounds
5bed, 5f, 5m, 5r and 5s exhibited good cytotoxic activity
(IC50 < 10 g/ml) against SK-N-MC cell line. The comparison of IC50
m
m
m
Scheme 1. Synthetic route for the preparation of compounds 5aev. Reagents and
conditions: (a) Morpholine, 4eCH3C6H4SO2OH (p-TSA), toluene, reflux; (b) nitro-
benzaldehyde, reflux and then, water, 50e55 ꢃC; (c) appropriate benzaldehyde
derivative, dry HCl gas, ethanol.
m
m
m
and appropriate nitrobenzaldehyde via enamine intermediate. The
reaction of compounds 7aec with substituted benzaldehyde under
acidicconditionsinethanolaffordedtargetcompounds5aev[17]. The
required bromoaldehyde 9 was prepared by bromination of vanillin
(8) using Br2 in acetic acid. O-Alkylation of bromovanillin 9 with
suitablealkyl iodideinthe presence of K2CO3 inDMF gaveappropriate
alkoxybenzaldehyde 10aed (Scheme 2).
m
values against MDA-MB 231 cell line revealed that propoxy deriv-
atives 5d, 5j and 5t had the most potent activity against this cell line
(IC50 ꢂ 4
5g, 5kem, 5o, 5r and 5u showed better activity (IC50
g/ml) than remaining compounds against
mg/ml). Apart from propoxy derivatives, compounds 5c,
values ¼ 5.01e8.99
m
The structural characterization of the new final compounds 5 is
based on their spectral data and elemental analyses. For example, the
FT-IR spectra of compounds 5 revealed two absorption bands at
1527e1502 and 1356e1335 cmꢀ1 characteristic to NO2 group. The FT-
IR spectra of the cyclohexanone derivatives also showed a very strong
nC¼O maximum about 1669e1659 cmꢀ1. Their 1H NMR spectra
MDA-MB-231 cells. The comparison of IC50 values of target
compounds 5aev with reference drug etoposide revealed that most
compounds were more potent than etoposide. For example the
activity of the most potent compound 5j was about 7e20 times
more than etoposide against tested cell lines.
Structurally, target compounds can categorized based on the
position of nitro group on the benzylidene moiety in three series.
According to the resulting data from limited numbers of derivatives of
2-nitrobenzylidene series 5aed, itcouldbe concluded thatcompound
5d containing 3-bromo-4-propoxy-5-methoxybenzylidene scaffold
showed better profile of cytotoxic activity against SK-N-MC and MDA-
revealed two signals at d 7.67e7.96 ppm assignable to vinylic protons
of bezylidenes. The survey in 13C NMR spectra of title compounds
revealedthatthecarbonylcarbonisdisplayeddownfield at >189 ppm.
3. Pharmacology
MB 231 cell lines (IC50 ꢂ 4.14
mg/ml).However,inthecaseofMCF-7, the
The in vitro anti-cancer activity of target compounds 5aev was
determined against MCF-7, MDA-MB 231 (breast cancer human cell
lines) and SK-N-MC (neuroblastoma) cells using MTT (3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method
[21]. Briefly, cell viability was assessed by MTT colorimetric assay in
which the viable cell number is directly proportional to the
production of purple formazan. This color product can be measured
spectrophotometrically at 550 nm by an ELISA plate reader. When
the amount of purple formazan produced by cells treated with
different concentration of test compounds is compared with the
amount of formazan produced by untreated control cells, the
inhibitory activity of compounds against tumor cells can be deduced
through the production of a doseeresponse curve.
growth inhibitory activity of 3-bromo-4,5-dimethoxybenzylidene
derivative 5c was statistically equal to that of 4-propoxy analog 5d.
Among the 3-nitro compounds, the highest activity against all cell
lines was also achieved by the introduction of 3-bromo-4-propoxy-5-
methoxybenzylidene group. In the 4-nitro series, the introduction of
3-bromo-4-ethoxy-5-methoxybenzylidene resulted in optimum
derivative (compound 5s) against MCF-7 and SK-N-MC cells, while
in the case of MDA-MB 231 cell line, similar to 2-nitro and 3-nitro
series, better activity was displayed by 3-bromo-4-propoxy-5-
methoxybenzylidene derivative (compound 5t). Thus, the effect of
4-alkoxy length (1Ce4C) is depending on the other substitutions and
the type of cell line.
Among the nitrobenzylidene compounds described in this
study, the cytotoxic activities of para-methoxy compounds 5a and
5e against different cell lines including human Mol 4/C8 and CEM T-
lymphocytes and murine L1210 cells have been reported by Dim-
mock et al. [17] These compounds were included in our study for
comparing their activities with poly-substituted compounds. As
seen from data, poly-substituted compounds for example 5d and 5j
had a better profile of cytotoxic activity in comparison to those of
mono-methoxylated compounds 5a and 5e.
Two independent experiments in triplicate were performed for
determination of growth inhibition for each compound. The IC50
were calculated by linear regression analysis, expressed in
Mean ꢁ SD. The standard drug etoposide was used to compare the
inhibitory activity.
4. Results and discussion
4.1. Cytotoxic activity
Previous studies have shown that
a,b-unsaturated carbonyl
compounds such as conjugated enones and dienones permit
a Michael addition of intracellular thiol compounds, such as
glutathione, to the olefinic double bond [15e17]. Specially, it has
been proposed that conjugated enones inhibit glutathione-S-
transferase, which enhances the cytotoxicity of these compounds
[11]. In (nitrobenzylidene)cyclohexanone derivatives, the strongly
electron-attracting nitro group cause the olefinic carbon atoms to
be electron deficient thereby enhances their expected reactivity
with the essential thiol groups [17]. Nevertheless, the reasons for
the relative cytotoxic potencies of target compounds are multifac-
torial and for example, the cytotoxic effect of compounds con-
taining 3-bromo-4,5-dialkoxyphenyl scaffold are frequently
associated with their ability to induce apoptosis in a variety of
cancer cell lines.
The results of cytotoxic activity were summarized as IC50 (mg/
ml) of compounds in Table 1. Generally, the IC50 values of
compounds demonstrated that all compounds showed significant
Scheme 2. Synthesis of aldehyde intermediates 9 and 10aed. Reagents and conditions:
(a) Br2, AcOH, rt; (b) alkyl iodide, K2CO3, DMF.

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M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
Table 1
Cytotoxic activity (IC50, mg/ml) of compounds 5aev.
O
R
O2N
.
Compound
NO2 position
2
R
MCF-7
SK-N-MC
MDA-MB-231
5a
5b
11.22 ꢁ 5.36
74.98 ꢁ 13.59
45.05 ꢁ 10.73
OCH3
2
2
5.62 ꢁ 2.37
3.35 ꢁ 2.48
4.49 ꢁ 0.73
6.24 ꢁ 1.38
14.33 ꢁ 4.25
8.99 ꢁ 2.19
OCH3
Br
5c
OCH3
OCH3
Br
CH3
5d
2
4.14 ꢁ 1.52
3.50 ꢁ 1.93
1.99 ꢁ 1.02
O
OCH3
5e
5f
3
3
5.71 ꢁ 1.15
4.17 ꢁ 1.84
10.36 ꢁ 1.24
4.94 ꢁ 1.78
44.70 ꢁ 11.94
13.17 ꢁ 3.53
OCH3
OCH3
5g
5h
3
3
5.14 ꢁ 2.11
4.72 ꢁ 2.36
10.08 ꢁ 2.57
16.70 ꢁ 4.13
5.59 ꢁ 1.91
H3CO
OCH3
Br
13.91 ꢁ 4.96
OCH3
OCH3
Br
5i
3
3
3
24.87 ꢁ 9.67
0.85 ꢁ 0.47
5.97 ꢁ 2.97
10.79 ꢁ 2.36
1.51 ꢁ 0.70
25.35 ꢁ 3.38
19.31 ꢁ 5.82
2.99 ꢁ 1.82
5.53 ꢁ 3.42
O
OCH3
CH3
Br
CH3
5j
O
OCH3
Br
5k
O
CH3
OCH3
5l
3
3
8.40 ꢁ 1.30
5.15 ꢁ 1.22
17.90 ꢁ 5.87
4.15 ꢁ 1.10
8.85 ꢁ 0.12
5.01 ꢁ 3.33
NO2
5m
Cl

M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
117
Table 1 (continued )
Compound
NO2 position
4
R
MCF-7
SK-N-MC
MDA-MB-231
5n
5o
5p
5q
5.82 ꢁ 1.84
11.53 ꢁ 1.75
51.38 ꢁ 14.85
6.73 ꢁ 2.56
13.08 ꢁ 6.08
>100
OCH3
4
4
4
13.32 ꢁ 5.69
7.05 ꢁ 3.63
4.93 ꢁ 0.83
22.15 ꢁ 4.83
48.02 ꢁ 8.44
16.80 ꢁ 3.50
H3CO
OCH3
OH
OCH3
Br
OH
OCH3
Br
5r
4
11.04 ꢁ 4.99
9.86 ꢁ 0.29
8.71 ꢁ 3.47
OCH3
OCH3
Br
5s
5t
4
4
4
4
3.08 ꢁ 1.10
7.98 ꢁ 3.73
27.01 ꢁ 5.72
3.91 ꢁ 0.91
23.27 ꢁ 27
34.70 ꢁ 10.28
4.01 ꢁ 1.32
8.38 ꢁ 1.93
O
OCH3
CH3
Br
CH3
O
OCH3
Br
5u
41.32 ꢁ 9.99
O
OCH3
CH3
5v
1.02 ꢁ 0.84
14.05 ꢁ 1.28
14.04 ꢁ 1.05
12.43 ꢁ 2.10
20.52 ꢁ 2.47
Cl
Etoposide
18.43 ꢁ 1.55
4.2. QSAR study
dipole moment and partial charges were calculated by the
Hyperchem software. Activity data were converted to loga-
rithmic scale (i.e. pIC50 for cytotoxicity in different cell lines). For
each set of descriptors, the best multi-linear regression equations
were obtained by the stepwise selection methods of multiple
linear regression (MLR) subroutine of SPSS software [22]. The
correlation coefficient (R2), standard error of regression (SE),
correlation coefficient for cross-validation significance (Q2), root
mean square error (RMS) and significant level (p-value) were
employed to judge the validity of regression equation. As co-
linearity degrades the performances of the MLR-based QSAR
equation, at the first, correlation analysis was performed to
detect the co-linear descriptors [23]. Thus, the correlation of
descriptors with each other and with activity data was examined
and among the co-linear descriptors one of them that repre-
sented the highest correlation with activity was retained and the
rest were omitted. The resulted correlation matrix is represented
in Table 2 for the remaining descriptors.
In order to evaluate the effects of the structural parameters of
the investigated derivatives 5aev on their cytotoxic activities,
QuantitativeeStructure Activity Relationship (QSAR) analysis
with different types of molecular descriptors was performed.
Several physicochemical descriptors such as hydrophobicity,
topological indices, electronic parameters and steric factors are
usually used in QSAR studies in order to find the effects of
different structural properties on the biological activity of
compound of interest. Since the calculated values of some elec-
tronic descriptors depend on the three-dimensional molecular
geometry, the optimum 3-D geometry of the molecules were
obtained by Hyperchem software (Hypercube Inc, USA), using
AM1 semi-empirical method. The resulting structures were used
to calculate constitutional, functional, geometrical and topolog-
ical descriptors by Dragon software. Meanwhile some electronic
descriptors such as frontier molecular orbital (HOMO, LUMO),

118
M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
Table 2
Correlation coefficient (R2) matrix for some of descriptors used in this study.
X4A
1
VRA2
GATS4p
DELS
qneg
0.009
ꢀ0.094
0.334
0.044
1
ATS5v
MATS1m
PJI3
X4A
ꢀ0.718
0.316
ꢀ0.176
1
ꢀ0.683
0.441
ꢀ0.277
1
ꢀ0.506
0.399
ꢀ0.790
0.350
ꢀ0.375
1
ꢀ0.152
ꢀ0.025
ꢀ0.649
0.387
ꢀ0.061
0.676
1
ꢀ0.523
0.534
ꢀ0.003
0.292
0.201
0.042
ꢀ0.225
1
VRA2
GATS4p
DELS
1
qneg
ATS5v
MATS1m
PJI3
In the first step, it was tried to find an appropriate model for
cytotoxic activity in SK-N-MC cell line. The obtained equation is
shown by Eq. (1):
The four-parametric equation, containing Geary autocorrelation
of lag 4 weighted by polarizability (GATS4p), average Randic-type
eigenvector-based index from adjacency matrix (VRA2), average
connectivity index of order 4 (X4A) and molecular electro-
topological variation (DELS) has squared correlation coefficient and
standard error equal to 0.895 and 0.116, respectively. The values of
the descriptors used by Eqs. (1) and (2) together with the predicted
-log IC50 (pIC50) are listed in Table 3. The correlation between the
observed and predicted activities of all the compounds using Eq. (1)
and Eq. (2) is represented graphically in Fig. 3A and Fig. 3B.
These two equations show that spatial and topological
descriptors play important role in cytotoxicity of these compounds.
The similarity of descriptors in equations suggests that molecules
produce cytotoxic effects through same mechanism. In a molecule,
Moran’s and Geary’s spatial autocorrelation analysis tests whether
the value of an atomic property at one atom in the molecular
structure is independent of the values of the property at neigh-
boring atoms. If dependence exists, the property is said to exhibit
spatial autocorrelation [24]. The autocorrelation vectors represent
the degree of similarity between molecules. Therefore, cytotoxic
activity of these series of compounds is mainly dependant on
molecular shape of structure.
pIC50 ¼ e 5.441(ꢁ9.432) e 3.463(ꢁ0.661)
GATS4p þ 153.528(ꢁ22.120) qneg e 46.014(ꢁ7.015) MATS1m
e 2.394(ꢁ0.467) PJI3 þ 14.287(ꢁ4.401) ATS5v
(1)
N
¼
21 R2
¼
0.912 RMScv
¼
0.162 SE
¼
0.147
Q2 ¼ 0.831 F ¼ 31.83.
In this equation, the values in the parenthesis represent the
standard deviation of the coefficients.
As seen in the Eq. (1), this equation has high statistical quality,
which can explain and predict 92.7% and 86% of variances in the
cytotoxic activity data in SK-N-MC cell line, respectively. This model
contains Geary autocorrelation of lag 4 weighted by polarizability
(GATS4p), maximum negative charge (qneg), Moran autocorrela-
tion of lag 1 weighted by mass (MATS1m), 3D Petitjean shape index
(PJI3) and Broto-Moreau autocorrelation of lag 5 (log function)
weighted by van der Waals volume (ATS5v).
The next equation was obtained for cytotoxicity of MCF-7 cell line:
pIC50 ¼ 50.344(ꢁ5.435) e 1.667(ꢁ0.261) GATS4p
e 0.166(ꢁ0.024) VAR2 e 324.104 (ꢁ42.216) X4A
5. Conclusion
e 0.043(ꢁ0.010) DELS
(2)
In conclusion, a series of asymmetrical 2,6-bis(benzylidene)
cyclohexanone derivatives containing nitrobenzylidene moiety were
synthesized and their cytotoxic activity were determined in vitro
N ¼ 20 R2 ¼ 0:893 RMScv ¼ 0:162 SE ¼ 0:116 Q2 ¼ 0:77
F ¼ 29:821.
Table 3
Data of the selected descriptors used in this study and predicted values of pIC50
.
Compound
X4A
VRA2
GATS4p
DELS
qneg
ATS5v
MATS1m
PJI3
Predicted pIC50
(SK-N-MC)
Predicted pIC50
(MCF-7)
5a
5b
5c
5d
5e
5f
5g
5h
5i
0.122
0.122
0.121
0.119
0.122
0.122
0.121
0.121
0.120
0.119
0.120
0.122
0.123
0.123
0.122
0.121
0.121
0.122
0.120
0.119
0.120
0.122
7.921
7.556
6.972
8.495
7.723
7.480
7.783
8.201
8.728
9.59
11.27
7.462
7.04
7.643
8.27
6.855
8.105
8.811
9.346
11.87
12.55
7.31
2.0830
2.0730
1.9280
1.779
31.590
31.815
37.803
39.433
30.495
30.717
35.308
36.686
37.644
38.305
38.868
41.983
30.798
29.968
34.541
39.026
39.048
35.922
36.872
39.118
38.335
29.814
0.361
0.365
0.365
0.363
0.360
0.362
0.361
0.362
0.360
0.361
0.361
0.360
0.359
0.364
0.364
0.362
0.364
0.362
0.364
0.362
0.361
0.360
0.430
0.431
0.471
0.485
0.421
0.423
0.439
0.463
0.470
0.451
0.438
0.416
0.433
0.420
0.436
0.429
0.445
0.460
0.468
0.442
0.440
0.425
0.9420
0.9420
0.9590
0.951
0.788
0.694
0.684
0.807
0.660
0.684
0.584
0.700
0.781
0.795
0.862
0.594
0.654
0.764
0.794
0.782
0.790
0.585
0.691
0.874
0.758
0.601
4.581
4.716
3.866
5.365
4.596
3.794
4.317
4.782
4.489
4.783
4.677
4.232
5.125
4.566
4.286
4.312
4.428
4.889
4.241
4.904
5.385
4.489
4.607
4.885
4.790
5.478
4.998
4.683
4.848
4.735
5.142
5.036
4.677
4.828
5.060
4.826
4.730
4.513
5.032
4.994
4.405
4.914
5.451
4.588
2.0130
2.0030
2.0680
1.8750
1.8720
1.7300
1.7760
1.9230
1.7940
2.0340
2.0960
2.0790
1.9420
1.8980
1.8950
2.0150
2.0350
1.9380
0.9420
0.9420
0.9410
0.9590
0.9550
0.9510
0.9480
0.9550
0.9570
0.942
0.9410
0.9450
0.9620
0.9590
0.9550
0.9480
0.9480
0.9570
5j
5k
5l
5m
5n
5o
5p
5q
5r
5s
5t
5u
5v

M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
119
NMR spectral data assignments, the atom numbering of
compounds 5a-v is depicted in Fig. 2. The IR spectra were taken
using Nicolet FT-IR Magna 550 spectrometer (KBr disks) (Nicolet,
Madison, WI, USA). MS spectra were obtained with a Finnigan MAT
TSQ-70 spectrometer (Finnigan MAT, Bremen, Germany). The
results of elemental analyses (C, H, N) were within ꢁ0.4% of theo-
retical values for C, H, and N.
O
CB
CA
2
2'
5'
1
1
1'
3
2
6
3'
R
O2N
5
6
3
6'
4
4'
4
5
Fig. 2. The atom numbering of compounds 5aev for NMR spectral data assignments.
6.2. General procedure for the synthesis of (E)-2-(nitrobenzylidene)
cyclohexanones 7aec
against MDA-MB 231, MCF-7 and SK-N-MC cell lines. Among the
tested compounds, the highest activity against MDA-MB 231 cells
was achieved by 2-(3-bromo-5-methoxy-4-propoxybenzylidene)-6-
(2-nitrobenzylidene)cyclohexanone (compound 5d). Its activity
against MDA-MB 231 cell line was 10-fold more than that of standard
drug etoposide. Whereas, compound 5j (the 3-nitro analog of
compound 5d) was the most potent compound against MCF-7 and
SK-N-MC cell lines. The activity of the compound 5j was about 7e20
times more than etoposide against tested cell lines. The results
indicated that the cytotoxic activity profile against different tumor
A solution of cyclohexanone (4.9 g, 0.05 mol), morpholine
(4.75 g, 0.055 mol), 4-toluenesulfonic acid (0.02 g) in toluene
(50 ml) was heated under reflux using a DeaneStark apparatus for
8 h. Then, nitrobenzaldehyde (6.8 g, 0.045 mol) was added to the
reaction mixture and heating under reflux was continued for 12 h.
Water (25 ml) was added to the reaction mixture and heated at
50e55 ꢃC for 1 h. The organic phase was separated, washed with
hydrochloric acid (5%, 20 ml) and water (3 ꢄ 50 ml), and dried.
Toluene was removed under reduced pressure to give a viscous oil
which was purified by chromatography using a column of silica gel
60 (70e230 mesh) and an eluting solvent of ethyl acetate/hexane
(1:9) to give 7aec [17].
cells
was
optimized
by
desired
4-alkoxy-3-bromo-5-
methoxybenzylidene scaffold. Also, the QSAR study demonstrated
that spatial and topological descriptors play important role in cyto-
toxicity of these compounds against MCF-7 and SK-N-MC cell lines.
6. Experimental protocols
6.2.1. 2-(2-Nitrobenzylidene)cyclohexanone (7a)
Yield 48%; m.p. 90e92 ꢃC; IR (KBr, cmꢀ1): 1671 (C]O), 1520 and
6.1. General methods
1335 (NO2). 1H NMR (CDCl3)
d: 8.11 (dd, J ¼ 8.0 and 1.5 Hz, 1H, H-3
aromatic), 7.62 (dt, J ¼ 8.0 and 1.5 Hz, 1H, H-5 aromatic), 7.59 (br s,
1H, ]CH), 7.49 (dt, J ¼ 8.0 and 1.5 Hz, 1H, H-4 aromatic), 7.32 (d,
J ¼ 8 Hz, 1H, H-6 aromatic), 2.57 (t, J ¼ 6.5 Hz, 2H, CH2-6 cyclo-
hexanone), 2.53 (dt, J ¼ 6.5 and 1.5 Hz, 2H, CH2-3 cyclohexanone),
1.97e1.90 (m, 2H, CH2-5 cyclohexanone), 1.77e1.70 (m, 2H, CH2-4
cyclohexanone). Anal. Calcd for C13H13NO3: C, 67.52; H, 5.67; N,
6.06. Found: C, 67.22; H, 5.37; N, 6.26.
All solvents, chemicals and reagents were obtained from Merck
Company (Darmstadt, Germany). The purity of all compounds was
confirmed by TLC using different eluting solvents. 1H NMR spectra
were measured using a Bruker 400 and 500 spectrometers (Bruker,
Rheinstetten, Germany) and chemical shifts are expressed as
d
(ppm) with tetramethylsilane (TMS) as internal standard. For
6.2.2. 2-(3-Nitrobenzylidene)cyclohexanone (7b)
Yield 47%; m.p. 50e52 ꢃC; IR (KBr, cmꢀ1): 1672 (C]O), 1526 and
1350 (NO2). 1H NMR (CDCl3)
d: 8.23 (s, 1H, H-2 aromatic), 8.17 (dd,
J ¼ 8.0 and 1.5 Hz, 1H, H-4 aromatic), 7.67 (d, J ¼ 8 Hz, 1H, H-6
aromatic), 7.57 (t, J ¼ 8 Hz, 1H, H-5 aromatic), 7.46 (br s, 1H, ¼CH),
2.84 (dt, J ¼ 6.5 and 2.0 Hz, 2H, CH2-3 cyclohexanone), 2.57 (t,
J ¼ 6.5 Hz, 2H, CH2-6 cyclohexanone), 1.99e1.93 (m, 2H, CH2-5
cyclohexanone), 1.84e1.77 (m, 2H, CH2-4 cyclohexanone). Anal.
Calcd for C13H13NO3: C, 67.52; H, 5.67; N, 6.06. Found: C, 67.47; H,
5.72; N, 5.96.
6.2.3. 2-(4-Nitrobenzylidene)cyclohexanone (7c)
Yield 52%; m.p. 118e120 ꢃC; IR (KBr, cmꢀ1): 1667 (C]O), 1516
and 1350 (NO2). 1H NMR (CDCl3)
d
: 8.24 (d, J ¼ 9 Hz, 2H, H-3 and H-
5 aromatic), 7.52 (d, J ¼ 9 Hz, 2H, H-2 and H-6 aromatic), 7.45 (br s,
1H, ¼CH), 2.82 (dt, J ¼ 6.5 and 2.0 Hz, 2H, CH2-3 cyclohexanone),
2.58 (t, J ¼ 6.5 Hz, 2H, CH2-6 cyclohexanone), 2.00e1.90 (m, 2H,
CH2-5 cyclohexanone), 1.83e1.76 (m, 2H, CH2-4 cyclohexanone).
Anal. Calcd for C13H13NO3: C, 67.52; H, 5.67; N, 6.06. Found: C,
67.52; H, 5.37; N, 6.18.
6.3. General procedure for the synthesis of 2-(substituted
benzylidene)-6-(nitrobenzylidene) cyclohexanones 5aev
Dry hydrogen chloride was passed into a solution of compound
7 (1 mmol) and the appropriate arylaldehyde (1 mmol) in ethanol
(5 ml). The reaction mixture was stirred at room temperature for
24 h and the resulting solid was collected and crystallized from
ethanol.
Fig. 3. Plots of cross-validated predicted values of activity by MLR against the exper-
imental values for different cell lines: (A) SK-N-MC and (B) MCF-7.

120
M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
6.3.1. 2-(4-Methoxybenzylidene)-6-(2-nitrobenzylidene)
cyclohexanone (5a)
135.7, 133.1, 132.4, 132.0, 131.1, 128.9, 126.4, 124.8, 117.80,
114.21,75.1, 56.1, 29.6, 28.5, 27.7, 23.4, 22.7, 10.4. Anal. Calcd for
C24H24BrNO5: C, 59.27; H, 4.97; N, 2.88. Found: C, 59.34; H, 5.26;
Yield 41%; m.p. 162e164 ꢃC; IR (KBr, cmꢀ1): 1664 (C]O), 1521
and 1337 (NO2). 1H NMR (CDCl3)
d
: 8.12 (d, J ¼ 8.5, 1H, H-30
N, 2.88.
aromatic), 7.94 (br s, 1H, ¼CBH), 7.80 (br s, 1H, ¼CAH), 7.64 (t,
J ¼ 7.5 Hz, 1H, H-50 aromatic), 7.49 (t, J ¼ 7.5 Hz, 1H, H-40 aromatic),
7.46 (d, J ¼ 8.5 Hz, 2H, H-2 and H-6 aromatic), 7.36 (d, J ¼ 7.5 Hz, 1H,
H-60 aromatic), 6.94 (d, J ¼ 8.5 Hz, 2H, H-3 and H-5 aromatic), 3.85
(s, 3H, OMe), 2.95e2.90 (m, 2H, CH2-5 cyclohexanone), 2.63e2.57
(m, 2H, CH2-3 cyclohexanone), 1.77 (quintet, 2H, J ¼ 6.5 Hz, CH2-4
6.3.5. 2-(4-Methoxybenzylidene)-6-(3-nitrobenzylidene)
cyclohexanone (5e)
Yield 50%; m.p. 129e131 ꢃC; IR (KBr, cmꢀ1): 1659 (C]O), 1502
and 1345 (NO2).1H NMR (CDCl3) : 8.30 (br s,1H, H-20 aromatic), 8.18
d
(dt, J ¼ 8.0 and 1.0 Hz, 1H, H-40 aromatic), 7.80 (br s, 1H, ¼CBH), 7.77
(br s,1H, ¼CAH), 7.73 (d, J ¼ 8 Hz,1H, H-60 aromatic), 7.58 (t, J ¼ 8 Hz,
1H, H-50 aromatic), 7.47 (d, J ¼ 8.5 Hz, 2H, H-2 and H-6 aromatic),
6.95 (dd, J ¼ 8.5 and 2.0 Hz, 2H, H-3 and H-5 aromatic), 3.85 (s, 3H,
OMe), 2.96(dt, J¼ 6.5 and2.0 Hz, 2H, CH2-5cyclohexanone), 2.92(dt,
J¼ 6.5 and 2.0 Hz, 2H, CH2-3cyclohexanone),1.83 (quintet, J¼ 6.5 Hz,
cyclohexanone). 13C NMR (CDCl3)
d: 189.3, 160.1, 148.3, 138.1, 137.9,
133.5, 132.9, 132.4, 132.3, 131.2, 128.8, 128.5, 124.8, 113.8, 55.3, 28.7,
27.8, 22.9. MS (m/z, %): 349 (Mþ, 62), 332 (81), 318 (26), 303 (100),
229 (18), 201 (38), 173 (25), 159 (29), 146 (38), 128 (26), 115 (38), 91
(18), 77 (35), 55 (12). Anal. Calcd for C21H19NO4: C, 72.19; H, 5.48; N,
4.01. Found: C, 71.95; H, 5.25; N, 3.88.
2H, CH2-4 cyclohexanone). 13C NMR (CDCl3)
d: 189.5, 160.2, 148.2,
138.7,137.9,137.7,136.1,133.5,133.2,132.4,129.3,128.3,124.3,122.9,
114.0, 55.3, 28.4, 28.3, 22.7. MS (m/z, %): 349 (Mþ, 74), 332 (100), 318
(31), 302 (32), 273 (12), 215 (12), 199 (15), 128 (18), 115 (25), 91 (12),
77 (15), 55 (12). Anal. Calcd for C21H19NO4: C, 72.19; H, 5.48; N, 4.01.
Found: C, 72.45; H, 5.21; N, 4.35.
6.3.2. 2-(3-Methoxybenzylidene)-6-(2-nitrobenzylidene)
cyclohexanone (5b)
Yield 43%; m.p. 122e124 ꢃC; IR (KBr, cmꢀ1): 1666 (C]O), 1516
and 1335 (NO2). 1H NMR (CDCl3)
d
: 8.13 (dd, J ¼ 7.5 and 1.0 Hz, 1H,
H-30 aromatic), 7.95 (br s, 1H, ¼CBH), 7.79 (br s, 1H, ¼CAH), 7.64 (dt,
J ¼ 7.5 and 1.0 Hz, 1H, H-50 aromatic), 7.50 (dt, J ¼ 7.5 and 1.0 Hz,
1H, H-40 aromatic), 7.37 (d, J ¼ 7.5 Hz, 1H, H-60 aromatic), 7.32 (t,
J ¼ 8 Hz, 1H, H-5 aromatic), 7.06 (d, J ¼ 8 Hz, 1H, H-6 aromatic),
6.99 (br s, 1H, H-2 aromatic), 6.90 (dd, J ¼ 8.0 and 2.0 Hz, 1H, H-4
aromatic), 3.83 (s, 3H, OMe), 2.92 (dt, J ¼ 6.0 and 2.0 Hz, 2H, CH2-5
cyclohexanone), 2.61 (dt, J ¼ 6.0 and 2.0 Hz, 2H, CH2-3 cyclohex-
anone), 1.76 (quintet, J ¼ 6 Hz, 2H, CH2-4 cyclohexanone). 13C NMR
6.3.6. 2-(3-Methoxybenzylidene)-6-(3-nitrobenzylidene)
cyclohexanone (5f)
Yield 89%; m.p.135e137 ꢃC; IR (KBr, cmꢀ1): 1664 (C]O),1526 and
1347 (NO2). 1H NMR (CDCl3) : 8.31 (br s, 1H, H-20 aromatic), 8.19 (dt,
d
J ¼ 8.0 and 1.0 Hz,1H, H-40 aromatic), 7.78 (br s, 2H, ¼CAH and ¼ CBH),
7.74 (d, J ¼ 8 Hz,1H, H-60 aromatic), 7.59 (t, J ¼ 8 Hz,1H, H-50 aromatic),
7.33 (t, J ¼ 8 Hz,1H, H-5 aromatic), 7.07 (d, J ¼ 8 Hz,1H, H-6 aromatic),
7.00 (br s, 1H, H-2 aromatic), 6.91 (dd, J ¼ 8.0 and 2.5 Hz, 1H, H-4
aromatic), 3.84 (s, 3H, OMe), 3.00e2.90 (m, 4H, CH2-3 and CH2-5
(CDCl3) d: 189.4, 159.4, 148.2, 137.8, 137.7, 137.1, 135.9, 132.9, 132.1,
131.1, 129.3, 128.8, 124.8, 122.8, 115.8, 114.4, 55.2, 28.5, 27.8, 22.9.
MS (m/z, %): 349 (Mþ, 63), 332 (100), 318 (36), 303 (37), 202 (15),
171 (14), 128 (16), 115 (31), 91 (12), 77 (15). Anal. Calcd for
C21H19NO4: C, 72.19; H, 5.48; N, 4.01. Found: C, 71.88; H, 5.65; N,
4.22.
cyclohexanone),1.82 (quintet, J ¼ 6 Hz, 2H, CH2-4 cyclohexanone).13
C
NMR (CDCl3)d:189.7,159.4,148.2,138.5,137.7,137.5,137.0,136.1,135.8,
133.7,129.4,124.3,123.0,115.8,114.4, 55.3, 28.3, 22.7. MS (m/z, %): 349
(Mþ, 29), 332 (100), 318 (51), 302 (30),115 (17), 69 (23). Anal. Calcd for
C21H19NO4: C, 72.19; H, 5.48; N, 4.01. Found: C, 71.92; H, 5.52; N, 4.22.
6.3.3. 2-(3-Bromo-4,5-dimethoxybenzylidene)-6-(2-
nitrobenzylidene)cyclohexanone (5c)
6.3.7. 2-(2,3-Dimethoxybenzylidene)-6-(3-nitrobenzylidene)
cyclohexanone (5g)
Yield 81%; m.p. 131e133 ꢃC; IR (KBr, cmꢀ1): 1669 (C]O), 1521
and 1342 (NO2). 1H NMR (CDCl3)
d
: 8.14 (dd, J ¼ 8.0 and 1.5 Hz, 1H,
Yield 32%; m.p. 130e131 ꢃC; IR (KBr, cmꢀ1): 1662 (C]O), 1525
H-30 aromatic), 7.95 (br s, 1H, ¼CBH), 7.68 (br s, 1H, ¼CAH), 7.65 (dt,
J ¼ 8.0 and 1.5 Hz,1H, H-50 aromatic), 7.51 (dt, J ¼ 8.0 and 1.5 Hz,1H,
H-40 aromatic), 7.37 (d, J ¼ 8 Hz, 1H, H-60 aromatic), 7.27 (d,
J ¼ 1.5 Hz, 1H, H-2 aromatic), 6.93 (d, J ¼ 1.5 Hz, 1H, H-6 aromatic),
3.88 (s, 6H, 2MeO), 2.94e2.87 (m, 2H, CH2-5 cyclohexanone),
2.64e2.57 (m, 2H, CH2-3 cyclohexanone), 1.81e1.74 (m, 2H, CH2-4
and 1351 (NO2). 1H NMR (CDCl3)
d
: 8.31 (t, J ¼ 2 Hz, 1H, H-20
aromatic), 8.19 (dt, J ¼ 8.4 and 1.2 Hz, 1H, H-40 aromatic) 7.96 (br s,
1H, ¼CBH), 7.78 (br s, 1H, ¼CAH), 7.74 (d, J ¼ 8.4 Hz, 1H, H-60
aromatic), 7.59 (t, J ¼ 8.4 Hz, 1H, H-50 aromatic), 7.08 (t, J ¼ 7.6 Hz,
1H, H-5 aromatic), 6.98e6.92 (m, 2H, H-4 and H-6 aromatic), 3.89
(s, 6H, OMe), 2.98e2.90 (m, 2H, CH2-5 cyclohexanone), 2.88e2.80
(m, 2H, CH2-3 cyclohexanone), 1.79 (quintet, J ¼ 6.8 Hz, 2H, CH2-4
cyclohexanone). Anal. Calcd for C22H21NO5: C, 69.64; H, 5.58; N,
3.69. Found: C, 69.75; H, 5.72; N, 3.45.
cyclohexanone). 13C NMR (CDCl3)
d: 189.1, 153.3, 148.2, 146.8, 137.5,
136.2, 135.9, 133.2, 133.0, 132.8, 132.0, 131.1, 128.9, 126.4, 124.9, 60.6,
56.1, 28.5, 27.7, 22.8. MS (m/z, %): 459 ([M þ 2]þ, 43), 457 (Mþ, 43),
442 (100), 413 (98), 378 (81), 259 (44), 120 (75), 77 (55), 55 (62).
Anal. Calcd for C22H20BrNO5: C, 57.66; H, 4.40; N, 3.06. Found: C,
57.92; H, 4.15; N, 3.18.
6.3.8. 2-(3-Bromo-4,5-dimethoxybenzylidene)-6-(3-
nitrobenzylidene)cyclohexanone (5h)
Yield 60%; m.p. 167e169 ꢃC; IR (KBr, cmꢀ1): 1659 (C]O), 1526
6.3.4. 2-(3-Bromo-5-methoxy-4-propoxybenzylidene)-6-(2-
nitrobenzylidene)cyclohexanone (5d)
and 1342 (NO2). 1H NMR (CDCl3) : 8.30 (br s, 1H, H-20 aromatic),
d
8.19 (dd, J ¼ 8.0 and 1.5 Hz, 1H, H-40 aromatic), 7.77 (br s, 1H, ¼CBH),
7.74 (d, J ¼ 8 Hz, 1H, H-60 aromatic), 7.67 (br s, 1H, ¼CAH), 7.59 (t,
J ¼ 8 Hz,1H, H-50 aromatic), 7.15 (d, J ¼ 2 Hz,1H, H-2 aromatic), 6.93
(d, J ¼ 2 Hz, 1H, H-6 aromatic), 3.89 (s, 6H, 2MeO), 3.00e2.88 (m,
4H, CH2-3 and CH2-5 cyclohexanone), 1.84 (quintet, J ¼ 6 Hz, 2H,
Yield 81%; m.p. 117e119 ꢃC; IR (KBr, cmꢀ1): 1665 (C]O), 1525
and 1356 (NO2). 1H NMR (CDCl3)
d
: 8.15 (dd, J ¼ 8.0 and 1.5 Hz, 1H,
H-30 aromatic), 7.95 (br s, 1H, ¼CBH), 7.69 (br s, 1H, ¼CAH), 7.67 (dt,
J ¼ 8.0 and 1.5 Hz, 1H, H-50 aromatic), 7.53 (dt, J ¼ 8.0 and 1.5 Hz,
1H, H-40 aromatic), 7.38 (d, J ¼ 8.0 Hz, 1H, H-60 aromatic), 7.29 (d,
J ¼ 1.5 Hz, 1H, H-2 aromatic), 6.94 (d, J ¼ 1.5 Hz, 1H, H-6 aromatic),
4.00 (t, J ¼ 7.6 Hz, 2H, CH2O), 3.88 (s, 3H, OMe), 2.98e2.88 (m, 4H,
CH2-3 and CH2-5 cyclohexanone), 1.88e1.76 (m, 4H, CH2-4 cyclo-
hexanone and eCH2- propoxy), 1.07 (t, 3H, J ¼ 7.6 Hz, CH3 pro-
CH2-4 cyclohexanone).13C NMR (CDCl3)
d: 189.3, 153.3, 148.2, 146.9,
138.3, 137.4, 136.1, 135.8, 133.9, 132.7, 129.4, 124.3, 123.1, 117.6, 114.1,
60.7, 56.1, 28.2, 22.6. MS (m/z, %): 459 ([Mþ2]þ, 21), 457 (Mþ, 21),
442 (33), 428 (25), 378 (100), 332 (21), 228 (18), 129 (18), 115 (25),
57 (16). Anal. Calcd for C22H20BrNO5: C, 57.66; H, 4.40; N, 3.06.
Found: C, 57.82; H, 4.15; N, 3.25.
poxy). 13C NMR (CDCl3)
d: 189.1, 153.3, 148.2, 146.3, 137.5, 136.3,

M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
121
6.3.9. 2-(3-Bromo-4-ethoxy-5-methoxybenzylidene)-6-(3-
nitrobenzylidene)cyclohexanone (5i)
for C20H16ClNO3: C, 67.90; H, 4.56; N, 3.96. Found: C, 67.95; H,
4.45; N, 4.15.
Yield 62%; m.p. 149e151 ꢃC; IR (KBr, cmꢀ1): 1664 (C]O), 1521
and 1347 (NO2).1H NMR (CDCl3)
d
: 8.30 (br s,1H, H-20 aromatic), 8.20
6.3.14. 2-(3-Methoxybenzylidene)-6-(4-nitrobenzylidene)
cyclohexanone (5n)
(d, J ¼ 8 Hz,1H, H-40 aromatic), 7.78 (br s,1H, ¼CBH), 7.74 (d, J ¼ 8 Hz,
1H, H-60 aromatic), 7.68 (br s, 1H, ¼CAH), 7.59 (t, J ¼ 8 Hz, 1H, H-50
aromatic), 7.29 (br s,1H, H-2 aromatic), 6.93 (br s,1H, H-6 aromatic),
4.12 (q, J ¼ 7 Hz, 2H, OCH2), 3.88 (s, 3H, OMe), 2.99e2.89 (m, 4H, H-3
and H-5 cyclohexanone), 1.89 (quintet, J ¼ 6 Hz, 2H, H-4 cyclohex-
Yield 35%; m.p. 149e151 ꢃC; IR (KBr, cmꢀ1): 1659 (C]O), 1516
and 1342 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 9 Hz, 2H, H-30 and H-
50 aromatic), 7.78 (t, J ¼ 2 Hz, 2H, ¼CAH and ¼ CBH), 7.58 (d, J ¼ 9 Hz,
2H, H-20 and H-60 aromatic), 7.34 (t, J ¼ 8 Hz,1H, H-5 aromatic), 7.07
(d, J ¼ 8 Hz, 1H, H-6 aromatic), 7.00 (br s, 1H, H-2 aromatic), 6.91
(dd, J ¼ 8.0 and 2.5 Hz, 1H, H-4 aromatic), 3.84 (s, 3H, OMe), 2.96
(dt, J ¼ 6.0 and 2.0 Hz, 2H, CH2-5 cyclohexanone), 2.91(dt, J ¼ 6.0
and 2.0 Hz, 2H, CH2-3 cyclohexanone), 1.82 (quintet, J ¼ 6 Hz, 2H,
anone), 1.43 (t, J ¼ 7 Hz, 3H, CH3). 13C NMR (CDCl3)
d: 189.3, 153.5,
148.2,146.2,138.3,137.5,136.2,136.0,135.7,133.9,132.4,129.4,126.6,
124.3, 123.0, 118.1, 114.1, 69.3, 56.1, 28.3, 28.2, 22.6, 15.6. MS (m/z, %):
473 ([Mþ2]þ, 32), 471 (Mþ, 32), 456 (44), 442 (32), 428 (11), 444 (11),
392 (100), 364 (52), 349 (11), 332 (15), 215 (15), 202 (17), 128 (22),
115 (28), 102 (11), 89 (14), 55 (11). Anal. Calcd for C23H22BrNO5: C,
58.49; H, 4.69; N, 2.97. Found: C, 58.72; H, 4.45; N, 3.10.
CH2-4 cyclohexanone). 13C NMR (CDCl3)
d: 189.6, 147.1, 142.5, 139.2,
137.8, 136.9, 135.7, 133.8, 130.7, 129.4, 123.5, 122.8, 114.4, 55.2, 28.3,
22.7. MS (m/z, %): 349 (Mþ, 64), 332 (48), 318 (100), 302 (17), 272
(10), 115 (17). Anal. Calcd for C21H19NO4: C, 72.19; H, 5.48; N, 4.01.
CHN Found: C, 71.88; H, 5.65; N, 3.87.
6.3.10. 2-(3-Bromo-5-methoxy-4-propoxybenzylidene)-6-(3-
nitrobenzylidene)cyclohexanone (5j)
Yield 64%; m.p. 108e110 ꢃC; IR (KBr, cmꢀ1): 1660 (C]O), 1527
6.3.15. 2-(2,3-Dimethoxybenzylidene)-6-(4-nitrobenzylidene)
cyclohexanone (5o)
and 1345 (NO2). 1H NMR (CDCl3) : 8.31 (s, 1H, H-20 aromatic), 8.20
d
(d, J ¼ 8.4 Hz, 1H, H-40 aromatic), 7.78 (s, 1H, ¼CBH), 7.74 (d,
J ¼ 8.4 Hz, 1H, H-60 aromatic), 7.68 (s, 1H, ¼CAH), 7.59 (t, J ¼ 8.4 Hz,
1H, H-50 aromatic), 7.29 (s, 1H, H-2 aromatic), 6.93 (s, 1H, H-6
aromatic), 4.00 (t, J ¼ 7.6 Hz, 2H, OCH2 propoxy), 3.88 (s, 3H, OMe),
2.98e2.90 (m, 4H, CH2-3 and CH2-5 cyclohexanone), 1.90e1.80 (m,
4H, CH2-4 cyclohexanone and eCH2- propoxy), 1.07 (t, J ¼ 7.6 Hz,
3H, CH3 propoxy). Anal. Calcd for C24H24BrNO5: C, 59.27; H, 4.97; N,
2.88. Found: C, 59.42; H, 5.15; N, 3.10.
Yield 69%; m.p. 163e165 ꢃC; IR (KBr, cmꢀ1): 1660 (C]O), 1514
and 1341 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 8.8 Hz, 2H, H-30 and
H-50 aromatic), 7.96 (t, J ¼ 2.1 Hz, 1H, ¼CBH), 7.78 (t, J ¼ 2.1 Hz,
1H, ¼CAH), 7.59 (d, J ¼ 8.8 Hz, 2H, H-20 and H-60 aromatic), 7.08 (t,
J ¼ 7.9 Hz, 1H, H-5 aromatic), 6.97e6.93 (m, 2H, H-4 and H-6
aromatic), 3.90 (s, 3H, OMe), 3.83 (s, 3H, OMe), 2.91 (dt, J ¼ 6.3 and
2.1 Hz, 2H, CH2-5 cyclohexanone), 2.85 (dt, J ¼ 6.3 and 2.1 Hz, 2H,
CH2-3 cyclohexanone), 1.79 (quintet, J ¼ 6.3 Hz, 2H, CH2-4 cyclo-
hexanone). 13C NMR (CDCl3)
d: 189.7, 152.9, 148.4,147.1,142.6, 139.4,
6.3.11. 2-(3-Bromo-4-butoxy-5-methoxybenzylidene)-6-(3-
nitrobenzylidene)cyclohexanone (5k)
136.8, 133.8, 133.5, 130.7, 130.0, 123.5, 122.0, 113.0, 61.1, 55.8, 28.6,
28.3, 22.9. Anal. Calcd for C22H21NO5: C, 69.64; H, 5.58; N, 3.69.
Found: C, 69.50; H, 5.80; N, 3.85.
Yield 47%; m.p. 144e145 ꢃC; IR (KBr, cmꢀ1): 1663 (C]O), 1525
and 1346 (NO2). 1H NMR (CDCl3) : 8.31 (s, 1H, H-20 aromatic), 8.19
d
(d, J ¼ 8 Hz, 1H, H-40 aromatic), 7.78 (s, 1H, ¼CBH), 7.74 (d, J ¼ 8 Hz,
1H, H-60 aromatic), 7.68 (s, 1H, ¼CAH), 7.59 (t, J ¼ 8 Hz, 1H, H-50
aromatic), 7.29 (s, 1H, H-2 aromatic), 6.93 (s,1H, H-6 aromatic), 4.04
(t, J ¼ 7.2 Hz, 2H, OCH2), 3.87 (s, 3H, OMe), 3.00e2.90 (m, 4H, CH2-3
and CH2-5 cyclohexanone), 1.95e1.78 (m, 4H, H-4 cyclohexanone
and eCH2- butoxy), 1.59e1.51 (m, 2H, eCH2- butoxy), 0.98 (t,
J ¼ 7.2 Hz, 3H, CH3 butoxy). Anal. Calcd for C25H26BrNO5: C, 60.01;
H, 5.24; N, 2.80. Found: C, 59.85; H, 5.35; N, 3.05.
6.3.16. 2-(4-Hydroxy-3-methoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5p)
Yield 47%; m.p.193e195 ꢃC; IR (KBr, cmꢀ1): 3324 (OH),1659 (C]
O),1516 and 1342 (NO2).1H NMR (CDCl3)
d
: 8.25 (d, J ¼ 9 Hz, 2H, H-30
and H-50 aromatic), 7.77 (br s, 2H, ¼CAH and ¼ CBH), 7.57 (d, J ¼ 9 Hz,
2H, H-20 and H-60 aromatic), 7.09 (dd, J ¼ 8.0 and 1.5 Hz, 1H, H-6
aromatic), 7.00 (d, J ¼ 1.5 Hz,1H, H-2 aromatic), 6.96 (d, J ¼ 8 Hz,1H,
H-5 aromatic), 5.89 (s, 1H, OH), 3.93 (s, 3H, OMe), 2.96 (dt, J ¼ 6.0
and 2.0 Hz, 2H, CH2-5 cyclohexanone), 2.89 (dt, J ¼ 6.0 and 2.0 Hz,
2H, CH2-3 cyclohexanone), 1.83 (quintet, J ¼ 6 Hz, 2H, CH2-4
6.3.12. 2-(3-Nitrobenzylidene)-6-(4-nitrobenzylidene)
cyclohexanone (5l)
cyclohexanone). 13C NMR (CDCl3)
d: 189.4, 147.1, 146.8, 146.3, 142.6,
Yield 40%; m.p. 186e188 ꢃC; IR (KBr, cmꢀ1): 1666 (C]O), 1525
139.4, 138.5, 134.8, 133.4, 130.7, 128.1, 124.7, 123.6, 114.5, 113.3, 55.9,
28.4, 22.7. MS (m/z, %): 365 (Mþ, 58), 348 (93), 332 (100), 318 (73),
302 (34), 128 (23), 115 (33), 57 (22). Anal. Calcd for C21H19NO5: C,
69.03; H, 5.24; N, 3.83. Found: C, 70.08; H, 5.05; N, 3.98.
and 1348 (NO2). 1H NMR (CDCl3)
d: 8.33 (br s, 1H, H-2 aromatic),
8.28 (d, J ¼ 8.8 Hz, 2H, H-30 and H-50 aromatic), 8.24e8.21 (m, 1H,
H-4 aromatic), 7.82 (br s, 2H, ¼CAH and ¼ CBH), 7.77 (d, J ¼ 8.8 Hz,
2H, H-6 aromatic), 7.65e7.63 (m, 1H, H-5 aromatic), 7.61 (d,
J ¼ 8.8 Hz, 2H, H-20 and H-60 aromatic), 3.01e2.94 (m, 4H, CH2-3
and CH2-5 cyclohexanone), 1.87 (quintet, J ¼ 6.2 Hz, 2H, CH2-4
cyclohexanone). Anal. Calcd for C20H16N2O5: C, 65.93; H, 4.43; N,
7.69. Found: C, 64.80; H, 4.65; N, 7.69.
6.3.17. 2-(3-Bromo-4-hydroxy-5-methoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5q)
Yield 36%; m.p. 216e218 ꢃC; IR (KBr, cmꢀ1): 3400 (OH), 1659
(C]O), 1593 and 1337 (NO2). 1H NMR (CDCl3)
d: 8.26 (d, J ¼ 8.6 Hz,
2H, H-30 and H-50 aromatic), 7.77 (br s, 1H, ¼CBH), 7.68 (br s,
1H, ¼CAH), 7.58 (d, J ¼ 8.6 Hz, 2H, H-20 and H-60 aromatic), 7.30 (s,
1H, H-2 aromatic), 6.93 (s, 1H, H-6 aromatic), 6.13 (s, 1H, OH), 3.94
(s, 3H, OMe), 2.98e2.93 (dt, J ¼ 6.0 and 2.0 Hz, 2H, CH2-5 cyclo-
hexanone), 2.92e2.87 (dt, J ¼ 6.0 and 2.0 Hz, 2H, CH2-3 cyclohex-
anone), 1.85 (quintet, J ¼ 6 Hz, 2H, CH2-4 cyclohexanone). 13C NMR
6.3.13. 2-(3-Chlorobenzylidene)-6-(3-nitrobenzylidene)
cyclohexanone (5m)
Yield 30%; m.p. 141e142 ꢃC; IR (KBr, cmꢀ1): 1662 (C]O), 1525
and 1348 (NO2). 1H NMR (CDCl3)
d
: 8.32 (t, J ¼ 1.8 Hz, 1H, H-20
aromatic), 8.22 (ddd, J ¼ 8.2, 2.2 and 0.95 Hz, 1H, H-40 aromatic),
7.80 (t, J ¼ 2 Hz, 1H, ¼CBH), 7.77 (br s, 1H, ¼CAH), 7.76e7.74 (m,
1H, H-60 aromatic), 7.61 (t, J ¼ 8.2 Hz, 1H, H-50 aromatic), 7.46 (br
s, 1H, H-2 aromatic), 7.38e7.33 (m, 3H, H-4, H-5 and H-6
aromatic), 2.98e2.92 (m, 4H, CH2-3 and CH2-5 cyclohexanone),
1.86 (quintet, J ¼ 6.2 Hz, 2H, CH2-4 cyclohexanone). Anal. Calcd
(CDCl3) d: 190.2, 161.2, 153.2, 150.1, 141.3, 140.2, 139.5, 131.6, 129.4,
128.4, 127.1, 123.8, 119.0, 116.1, 57.6, 38.3, 24.4. MS (m/z, %): 445
([Mþ2]þ, 37), 443 (Mþ, 37), 414 (18), 379 (45), 364 (100), 214 (18),
115 (22), 89 (13). Anal. Calcd for C21H18BrNO5: C, 56.77; H, 4.08; N,
3.15. Found: C, 56.82; H, 3.95; N, 2.98.

122
M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
6.3.18. 2-(3-Bromo-4,5-dimethoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5r)
2H, CH2-4 cyclohexanone). Anal. Calcd for C20H16ClNO3: C, 67.90; H,
4.56; N, 3.96. Found: C, 67.90; H, 4.70; N, 3.88.
Yield 36%; m.p. 148e150 ꢃC; IR (KBr, cmꢀ1): 1664 (C]O), 1516
and 1347 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 8.5 Hz, 2H, H-30 and
6.4. Preparation of 3-bromo-4-hydroxy-5-methoxybenzaldehyde
(9) [25]
H-50 aromatic), 7.77 (br s, 1H, ¼CBH), 7.68 (br s, 1H, ¼CAH), 7.58 (d,
J ¼ 8.5 Hz, 2H, H-20 and H-60 aromatic), 7.28 (d, J ¼ 2 Hz, 1H, H-2
aromatic), 6.94 (d, J ¼ 2 Hz, 1H, H-6 aromatic), 3.90 (s, 3H, OMe),
3.89 (s, 3H, OMe), 2.97e2.87 (m, 4H, CH2-3 and CH2-5 cyclohexa-
A solution of bromine (10.5 g, 6.8 mmol) in glacial acetic acid
(20 ml) was added dropwise to a solution of vanillin (10.0 g,
6.5 mmol) in glacial acetic acid. The mixture was stirred at rt for
1 h. After ascertaining the completion of the reaction by TLC, the
white precipitated solid was collected, washed with acetic acid
and recrystallized (ethanol) to give the desired compound 9. Yield
77%; m.p. 163e165 ꢃC; IR (KBr, cmꢀ1): 3329 (OH), 1669 (C]O). 1H
none), 1.88e1.80 (m, 2H, CH2-4 cyclohexanone). 13C NMR (CDCl3)
d:
189.2, 153.3, 147.1, 142.3, 139.0, 136.2, 135.7, 134.0, 132.6, 130.7,
126.5, 123.5, 117.6, 114.1, 60.6, 56.1, 28.3, 22.6. MS (m/z, %): 459
([Mþ2]þ, 64), 457 (Mþ, 64), 428 (41), 378 (100), 319 (25), 228 (23),
115 (25). Anal. Calcd for C22H20BrNO5: C, 57.66; H, 4.40; N, 3.06
Found: C, 57.83; H, 4.55; N, 3.22.
NMR (CDCl3)
d
: 9.66 (s, 1H, CHO), 7.53 (d, J ¼ 3 Hz, 1H, H-2
aromatic), 7.47 (s, 1H, OH), 7.23 (d, J ¼ 3 Hz, 1H, H-6 aromatic), 3.85
6.3.19. 2-(3-Bromo-4-ethoxy-5-methoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5s)
(s, 3H, OMe).
Yield 30%; m.p. 148e150 ꢃC; IR (KBr, cmꢀ1): 1669 (C]O), 1516
and 1342 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 9 Hz, 2H, H-30 and H-
6.5. General procedure for the preparation of 4-alkoxy-3-bromo-5-
methoxybenzaldehyde (10aed) [26,27]
50 aromatic), 7.77 (br s, 1H, ¼CBH), 7.68 (br s, 1H, ¼CAH), 7.58 (d,
J ¼ 9 Hz, 2H, H-20 and H-60 aromatic), 7.29 (d, J ¼ 2 Hz, 1H, H-2
aromatic), 6.93 (d, J ¼ 2 Hz, 1H, H-6 aromatic), 4.12 (q, J ¼ 7 Hz, 2H,
OCH2), 3.88 (s, 3H, OMe), 2.94 (dt, J ¼ 7.0 and 2.0 Hz, 2H, CH2-5
cyclohexanone), 2.90 (dt, J ¼ 7.0 and 2.0 Hz, 2H, CH2-3 cyclohexa-
none), 1.84 (quintet, J ¼ 7 Hz, 2H, CH2-4 cyclohexanone), 1.43 (t,
A solution of potassium carbonate (1 mmol) and compound 9
(1 mmol) in DMF (25 ml) was heated to 80 ꢃC after 5 min, alkyl
iodide (20 mmol) was added to the reaction mixture and the
completion of reaction was followed by TLC. After the reaction was
completed, the mixture was allowed to cool to rt. Then, the mixture
was extracted with diethyl ether (3 ꢄ 25 ml). The combined organic
extracts were washed with water, dried over sodium sulfate and
then the solvent was evaporated to give the desired benzaldehyde
10aed.
J ¼ 7 Hz, 3H, CH3). 13C NMR (CDCl3)
d: 189.3, 153.5, 147.2, 146.3,
142.4, 139.1, 136.4, 135.6, 134.0, 132.4, 130.7, 126.5, 123.6, 114.1, 69.3,
56.1, 28.3, 22.6, 15.6. MS (m/z, %): 473 ([Mþ2]þ, 54), 471 (Mþ, 54),
442 (41), 414 (17), 392 (100), 364 (88),128 (23),115 (27). Anal. Calcd
for C23H22BrNO5: C, 58.49; H, 4.69; N, 2.97. Found: C, 58.62; H, 4.35;
N, 3.08.
6.5.1. 3-Bromo-4,5-dimethoxybenzaldehyde (10a)
Yield 71%; m.p. 70e72 ꢃC; IR (KBr, cmꢀ1): 1685 (C]O). 1H NMR
6.3.20. 2-(3-Bromo-5-methoxy-4-propoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5t)
(CDCl3)
d
: 9.84 (s, 1H, CHO), 7.64 (d, J ¼ 2 Hz, 1H, H-2 aromatic), 7.38
Yield 66%; m.p. 125e127 ꢃC; IR (KBr, cmꢀ1): 1664 (C]O), 1515
(d, J ¼ 2 Hz, 1H, H-6 aromatic), 3.94 (s, 3H, OMe), 3.93 (s, 3H, OMe).
and 1340 (NO2).1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 8.4 Hz, 2H, H-30 and H-
Anal. Calcd for C9H9BrO3: C, 44.11; H, 3.70. Found: C, 44.18; H, 3.50.
50 aromatic), 7.78 (br s, 1H, ¼CBH), 7.68 (br s, 1H, ¼CAH), 7.58 (d,
J ¼ 8.4 Hz, 2H, H-20 and H-60 aromatic), 7.29 (d, J ¼ 2 Hz, 1H, H-2
aromatic), 6.93 (d, J ¼ 2 Hz,1H, H-6 aromatic), 4.00 (t, J ¼ 7.6 Hz, 2H,
CH2O), 3.87 (s, 3H, OMe), 2.98e2.88 (m, 4H, CH2-3 and CH2-5
cyclohexanone),1.90e1.80 (m, 4H, CH2-4 cyclohexanone and eCH2-
propoxy), 1.06 (t, J ¼ 7.6 Hz, 3H, CH3 propoxy). Anal. Calcd for
C24H24BrNO5: C, 59.27; H, 4.97; N, 2.88. Found: C, 59.35; H, 5.25; N,
2.88.
6.5.2. 3-Bromo-4-ethoxy-5-methoxybenzaldehyde (10b)
Yield 71%; m.p. 70e72 ꢃC; IR (KBr, cmꢀ1): 1685 (C]O). 1H NMR
(CDCl3)
d
: 9.84 (s, 1H, CHO), 7.65 (d, J ¼ 2 Hz, 1H, H-2 aromatic), 7.38
(d, J ¼ 2 Hz, 1H, H-6 aromatic), 4.19 (q, J ¼ 7 Hz, 2H, OCH2), 3.92 (s,
3H, OMe), 1.44 (t, J ¼ 7 Hz, 3H, CH3). Anal. Calcd for C10H11BrO3: C,
46.36; H, 4.28. Found: C, 46.16; H, 4.29.
6.5.3. 3-Bromo-5-methoxy-4-propoxybenzaldehyde (10c)
Yield 79%; oil; IR (KBr, cmꢀ1): 1696 (C]O). 1H NMR (CDCl3)
d:
6.3.21. 2-(3-Bromo-4-butoxy-5-methoxybenzylidene)-6-(4-
nitrobenzylidene)cyclohexanone (5u)
9.83 (s, 1H, CHO), 7.65 (d, J ¼ 1.6 Hz, 1H, H-2 aromatic), 7.37 (d,
J ¼ 1.6 Hz, 1H, H-6 aromatic), 4.07 (t, J ¼ 6.8 Hz, 2H, OCH2), 3.91 (s,
3H, OMe), 1.92 (m, 2H, eCH2-), 1.06 (t, J ¼ 6.8 Hz, 3H, CH3 propoxy).
Anal. Calcd for C11H13BrO3: C, 48.37; H, 4.80. Found: C, 48.45; H,
4.95.
Yield 57%; m.p. 89e90 ꢃC; IR (KBr, cmꢀ1): 1665 (C]O), 1511 and
1339 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 8 Hz, 2H, H-30 and H-50
aromatic), 7.78 (s, 1H, ¼CBH), 7.68 (s, 1H, ¼CAH), 7.58 (d, J ¼ 8 Hz,
2H, H-20 and H-60 aromatic), 7.29 (s, 1H, H-2 aromatic), 6.93 (s, 1H,
H-6 aromatic), 4.04 (t, J ¼ 7.2 Hz, 2H, OCH2), 3.87 (s, 3H, OMe),
3.00e2.86 (m, 4H, CH2-3 and CH2-5 cyclohexanone), 1.90e1.75 (m,
4H, CH2-4 cyclohexanone and eCH2- butoxy), 1.63e1.48 (m,
2H, eCH2- butoxy), 0.98 (t, J ¼ 7.2 Hz, 3H, CH3 butoxy). Anal. Calcd
for C25H26BrNO5: C, 60.01; H, 5.24; N, 2.80. Found: C, 60.15; H, 5.45;
N, 2.98.
6.5.4. 3-Bromo-4-butoxy-5-methoxybenzaldehyde (10d)
Yield 65%; oil; IR (KBr, cmꢀ1): 1695 (C]O). 1H NMR (CDCl3)
d:
9.83 (s, 1H, CHO), 7.63 (d, J ¼ 1.6 Hz, 1H, H-2 aromatic), 7.37 (d,
J ¼ 1.6 Hz, 1H, H-6 aromatic), 4.11 (t, J ¼ 6.8 Hz, 2H, OCH2), 3.91 (s,
3H, OMe), 1.87 (m, 2H, eCH2-), 1.60e1.49 (m, 2H, eCH2-), 0.98 (t,
J ¼ 6.8 Hz, 3H, CH3 butoxy). Anal. Calcd for C12H15BrO3: C, 50.19; H,
5.27. Found: C, 49.95; H, 5.45.
6.3.22. 2-(4-Chlorobenzylidene)-6-(4-nitrobenzylidene)
cyclohexanone (5v)
Yield 40%; m.p. 148e149 ꢃC; IR (KBr, cmꢀ1): 1663 (C]O), 1516
Acknowledgment
and 1344 (NO2). 1H NMR (CDCl3)
d
: 8.26 (d, J ¼ 8.8 Hz, 2H, H-30 and
H-50 aromatic), 7.78 (br s, 1H, ¼CBH), 7.76 (br s, 1H, ¼CAH), 7.59 (d,
J ¼ 8.8 Hz, 2H, H-20 and H-60 aromatic), 7.46e7.34 (m, 4H, aromatic),
3.02e2.82 (m, 4H, CH2-3 and CH2-5 cyclohexanone), 1.98e1.78 (m,
This work was supported by grants from the research council of
Tehran University of Medical Sciences and Iran National Science
Foundation (INSF).

M. Nakhjiri et al. / European Journal of Medicinal Chemistry 50 (2012) 113e123
123
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