Hybrid benzofuran-bisindole derivatives: New prototypes with promising anti-hyperlipidemic activities

Article abstract of DOI:10.1016/j.ejmech.2013.07.009

A series of different benzofuran-bisindole hybrids were synthesized and evaluated in vitro for their antioxidant and in vivo for antidyslipidemic activity in triton WR-1339 induced hyperlipidemic rats. Among the series, compounds 4a, 4c, 4h and 4j showed

Full text of DOI:10.1016/j.ejmech.2013.07.009

European Journal of Medicinal Chemistry 68 (2013) 38e46
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European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Hybrid benzofuranebisindole derivatives: New prototypes
with promising anti-hyperlipidemic activitiesq
,
a
b
a
Koneni V. Sashidhara a , Ram K. Modukuri , Ravi Sonkar , K. Bhaskara Rao ,
*
Gitika Bhatia b
a Medicinal and Process Chemistry Division, CSIR e Central Drug Research Institute, Lucknow 226 001, Uttar Pradesh, India
b Biochemistry Division, CSIR e Central Drug Research Institute, Lucknow 226 001, India
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of different benzofuranebisindole hybrids were synthesized and evaluated in vitro for their
antioxidant and in vivo for antidyslipidemic activity in triton WR-1339 induced hyperlipidemic rats.
Among the series, compounds 4a, 4c, 4h and 4j showed significant decrease in plasma levels of total
cholesterol (TC), phospholipids (PL) and triglycerides (TG) followed by increase in post heparin lipolytic
activity (PHLA). In addition, the active hybrids possessed moderate antioxidant properties and increased
the plasma lecithin cholesterol acyltransferase (LCAT) activity, which plays a key role in lipoprotein
metabolism contributing to an increased level of HDL-C in serum. These results indicate that these hy-
brids constitute novel prototypes for the management of dyslipidemia.
Received 26 March 2013
Received in revised form
15 July 2013
Accepted 21 July 2013
Available online 30 July 2013
Keywords:
Benzofuranebisindole
Lipid lowering activity
Lipoprotein metabolism
LCAT activity
Ó 2013 Elsevier Masson SAS. All rights reserved.
Triton model
1. Introduction
generic name) still remains the best selling branded lipid lowering
drug worldwide [6]. However, disorders of muscles, (rhabdomyol-
Hyperlipidemia, a key feature of the metabolic syndrome and is
the major cause of heart disease, stroke and death in most indus-
trialized world [1]. It is estimated that nearly 31.9 million US adults
have total serum cholesterol levels ꢀ240 mg/dL, and 13.8% are with
a prevalence of cardiovascular risk and this is set to rise in future
[2]. The typical characteristics of hyperlipidemia are high plasma
triglyceride (TG) concentration, low high density lipoprotein
cholesterol (HDL-C) concentration and increased concentration of
small density lipoprotein cholesterol (LDL-C) particles [3]. Current
available therapies for hyperlipidemia include statins, fibrates,
niacin/nicotinic acid and bile acid sequestrants [4]. Statins such as
atorvastatin, lovastatin, fluvastatin, simvastatin, and pravastatin
work via inhibition of HMG-CoA reductase, a key enzyme in
cholesterol biosynthetic pathway, leading to a reduced cholesterol
concentration and a consequent increase in expression of the low-
density lipoprotein receptor (LDLR), the main receptor involved in
the hepatic clearance of LDL cholesterol [5]. Atorvastatin (Lipitor
ysis) leading to withdrawal of cerivastatin in 2001 and in light of
the recent warning by the US FDA, ( February 28th, 2012. http://
www.fda.gov/safety Alerts) that statins may increase the risk of
diabetes mellitus, clearly underscores the constant need for new
class of drug to combat this dreaded metabolic disorder without
severe side effects [7].
Increase in oxidative stress has been frequently implicated in
the pathogenesis of several other metabolic risk factors such as
diabetes and coronary heart disease (CAD) [8]. Reactive oxygen
species, such as hydrogen peroxide (H2O2), superoxide anions (O2.ꢁ
)
or hydroxyl radicals (,OH), which are a by-product of oxidative
metabolism, can damage the cells resulting in lipid peroxidation,
modification of protein and nucleic acids. Excess of hydroxyl free
radicals are the major factor for the peroxidative damage to lipo-
proteins present in the blood, which are responsible for the initi-
ation and progression of atherosclerosis in the hyperlipidemic
conditions [9]. Due to multifactorial nature of the metabolic syn-
drome, it is envisaged that compounds endowed with both hypo-
lipidemic and antioxidant properties will be able to offer a better
therapeutic benefit.
q
Part XXV in the series, “Advances in drug design and discovery”.
Indoles are an important structural motif found in numerous
natural products and they exhibit diverse biological activities
including antioxidant properties [10]. Also, it is interesting to note
* Corresponding author. Tel.: þ91 9919317940; fax: þ91 522 2628493.
E-mail
addresses:
sashidhar123@gmail.com,
kv_sashidhara@cdri.res.in
(K.V. Sashidhara).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.07.009

K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
39
the presence of this important scaffold in fluvastatin, which is a
statin class of drug. Our previous laboratory experiences with this
framework clearly demonstrated its promising lipid lowering
properties [11]. On the other hand, benzofuran derivatives are
versatile biodynamic agents that can be used to design and develop
new potentially useful therapeutic agents [12]. In addition,
the benzofuran containing natural product tourefolic acids A and
acclimatized for one week before starting the experiment, had free
access to the normal diet and water.
3.2. Lipid lowering and plasma post heparin lipolytic activity
Rats were divided into twelve groups control, triton induced,
triton plus 4aes and gemfibrozil (100 mg/kg) treated groups,
containing six rats in each group. In this experiment of 18 h,
hyperlipidemia was developed by administration of triton WR-
1339 (Sigma chemical company, St. Louis, MO, USA) at a dose of
400 mg/kg body weight intraperitoneally to animals of all the
groups except the control. These derivatives were macerated with
gum acacia (0.2% w/v), suspended in water and fed simultaneously
with triton with a dose of 100 mg/kg p.o. to the animals of treated
group and the diet being withdrawn. Animals of control and triton
group without treatment with amide based fibrate compounds
were given same amount of gum acacia suspension (vehicle). After
18 h of treatment the animals were anaesthetized with thio-
pentone solution (50 mg/kg b.w.) prepared in normal saline and
then 1.0 mL blood was withdrawn from retro-orbital sinus using
glass capillary in EDTA coated eppendorf tube (3.0 mg/ml blood).
The blood was centrifuged (at 2500 g) at 4 ꢂC for 10 min and
plasma was separated. Plasma was diluted with normal saline
(ratio of 1:3) and used for analysis of total cholesterol (TC), tri-
glycerides (TG) and phospholipids (PL) by standard enzymatic
methods [19] and post heparin lipolytic activity (PHLA) were
assayed [20] using spectrophotometer, Beckmann auto-analyzer
and standard kits purchased from Beckmann Coulter Interna-
tional, USA.
B
have shown potent anti-lipid-peroxidative properties [13].
Furthermore, a literature survey and based on the framework re-
veals that benzofuran ring containing moiety, exhibit anti-
hyperlipidemic activity (Fig. 1) [14]. These studies, suggested that
compounds containing this ring might have a potential lipid-
lowering effect. In continuation of our drug discovery program on
new antidyslipidemic agents, and our laboratory experiences on
molecular hybridization approach [15,16], a series of new benzo-
furan based bisindoles prototypes were synthesized (our prototype
in Fig. 1) and evaluated for their anti-hyperlipidemic activity.
2. Chemistry
The synthesis of target and intermediate compounds is outlined
in the Scheme 1. The modified Duff reaction [17] on ortho-
substituted phenols (1aef) in the presence of hexamethylenetet-
ramine (HMTA) and TFA at 120 ꢂC followed by hydrolysis using 10%
aqueous H2SO4 solution gave the dicarbaldehyde intermediates
(2aef). The RapeStoermer reaction [18] on compounds (2aef) with
different phenacylbromides in the presence of K2CO3 furnished
benzofuran carbaldehyde derivatives (3aem) in quantitative yields.
Further, the introduction of indole template was achieved by the
reaction of different indoles in the presence of iodine and aceto-
nitrile as a solvent at room temperature to give the final benzo-
furanebisindole hybrids (4aes) in excellent yields. All the
3.3. Lipoprotein measurement in blood plasma of triton induced
hyperlipidemic rats
synthesized compounds were characterized by using 1H NMR, 13
NMR, IR spectroscopy and ESI-MS.
C
Plasma was fractionated into very low density lipoprotein
(VLDL), low density lipoprotein (LDL) and high density lipoprotein
(HDL) by polyanionic precipitation methods. Plasma and lipopro-
teins were analyzed for their TC, PL and TG [11].
3. Pharmacology
3.1. Animals used
3.4. Measurement of lipoprotein cholesterol level and LCAT activity
Rats (Charles Foster strain, male, adult, body weight 200e225 g)
were kept in a room with controlled temperature (25e26 ꢂC), hu-
midity (60e80%) and 12/12 h light/dark cycle (light on from 8.00
A.M. to 8.00 P.M.) under hygienic conditions. Animals, which were
Serum was fractionated into very low density lipoprotein
(VLDL), low density lipoprotein (LDL) and high density lipopro-
tein (HDL) by polyanionic precipitation methods. Plasma and li-
poproteins were analyzed for their TC, PL and TG by standard
Fig. 1. Chemical structure of some potent lipid modulating indoles, benzofurans and general structure of our prototype.

40
K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
Reagents and conditions: (i) HMTA / TFA, 120 ºC, 3h; (ii) 10% H2SO4, 90-100 ºC, 2h (iii)
Different substituted phenacyl bromides, K2CO3/CH3CN, reflux, 3h (iv) Different substituted
indoles, I2/CH3CN, r.t, 0.5h.
Scheme 1. Synthesis of novel benzofuranebisindole hybrids.
procedures reported earlier [21]. Serum lecithin: cholesterol
acetyltransferase (LCAT) activity was measured using method
reported earlier [22].
3.6. Statistical evaluation
Data were analyzed using student’s t-test. The hyperlipidemic
groups were compared with control drug treated groups. P < 0.05
was considered to be significant.
3.5. Antioxidant activity (generation of free radicals)
Superoxide anions (Oꢁ2 ) were generated enzymatically [23] by
xanthine (160 mM), xanthine oxidase (0.04 U) and nitroblue
4. Results and discussion
tetrazolium (320
mM) in absence or presence of compounds
(200 g/ml) in 100 mM phosphate buffer (pH 8.2). Fractions were
m
4.1. The lipid lowering activity of benzofuranebisindole hybrids
sonicated well in phosphate buffer before use. The reaction
mixtures were incubated at 37ꢂ C and after 30 min the reaction
was stopped by adding 0.5 mL glacial acetic acid. The amount of
formazone formed was measured at 560 nm on a spectropho-
tometer. Percentage inhibition was calculated taking absorption
coefficient of formazone as 7.2 ꢃ 103 Mꢁ1 1cmꢁ1. In another set of
experiment, an effect of compounds on generation of hydroxyl
radicals (,OH) was also studied by non-enzymic reactants [24].
Briefly (,OH) were generated in a non-enzymic system comprised
of deoxy ribose (2.8 mM), FeSO4$7H2O (2 mM), sodium ascorbate
Administration of triton WRe1339 in rats induced markedly
increased the plasma level of TC (4.0 fold), PL (3.3 fold) and TG (2.6
fold) and PHLA (30%) as compared to control. Treatment of hyper-
lipidemic rats with benzofuranebisindole hybrids 4(aes) at the
dose of 100 mg/kg p.o. reversed the plasma levels of lipids with
varying extents. However among these, the activity of 4a, 4c, 4h
and 4j was more pronounced. Compound 4j was found to be the
most potent in the series as it exhibited 28%, 29%, and 28% lowering
in TC, PL and TG respectively. The lipid lowering levels of these four
actives were comparable with that of the standard hypolipidemic
drug gemfibrozil, which at the same dose of 100 mg/kg decreased
levels of TC, PL and TG in plasma by 34%, 35% and 34%, respectively.
Compounds 4a, 4c, 4h and 4j showed significant reversal of PHLA in
plasma of hyperlipidemic rats by 16%, 17%,16% and 18% respectively,
comparable to gemfibrozil, which caused 20% reversal of activity of
this enzyme as compared to control group and the results are
summarized in Table 1.
(2.0 mM) and H2O2 (2.8 mM) in 50
final volume of 2.5 mL. The above reaction mixtures in the
absence or presence of compounds (200 g/ml) were incubated at
mM KH2PO4 buffer, pH 7.4 to a
m
37 ꢂC for 90 min. Reference samples and reagent blanks were also
run simultaneously. Malondialdehyde (MDA) content in both
experimental and reference samples were estimated spectro-
photometrically by thiobarbituric acid method as mentioned
above [25].

K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
41
Table 1
Percentage (%) change of plasma lipids with the treatment of benzofuranebisindole hybride molecules in triton-induced hyperlipidemic rats at the dose of 100 mg/kg body
weight.
Compound no.
Lipid profile
PHLAb
Total cholesterol (TC)a
Phospholipids (PL)a
Triglyceride (TG)a
Control
Triton
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
93.74 ꢄ 8.51
89.31 ꢄ 8.06
90.64 ꢄ 6.98
17.42 ꢄ 1.64
184.21 ꢄ 15.81c (þ1.9Fold)
141.84 ꢄ 10.74*** (ꢁ23)
152.89 ꢄ 11.69* (ꢁ17)
139.99 ꢄ 9.63*** (ꢁ24)
147.36 ꢄ 13.77** (ꢁ20)
145.52 ꢄ 11.36** (ꢁ21)
206.88 ꢄ 18.62c (þ2.3Fold)
159.29 ꢄ 15.11*** (ꢁ23)
175.84 ꢄ 11.59* (ꢁ15)
159.29 ꢄ 10.08*** (ꢁ23)
163.43 ꢄ 10.94** (ꢁ21)
165.50 ꢄ 12.86** (ꢁ20)
186.19 ꢄ 14.86* (ꢁ10)
186.19 ꢄ 14.57* (ꢁ10)
216.11 ꢄ 20.02c (þ2.3 Fold)
164.24 ꢄ 12.48*** (ꢁ24)
181.53 ꢄ 17.39* (ꢁ16)
166.40 ꢄ 10.28*** (ꢁ23)
170.72 ꢄ 17.08** (ꢁ21)
168.56 ꢄ 12.65** (ꢁ22)
194.40 ꢄ 18.63* (ꢁ10)
193.81 ꢄ 16.86* (ꢁ10)
166.40 ꢄ 9.64*** (ꢁ23)
200.98 ꢄ 18.88 NS (ꢁ7)
155.59 ꢄ 11.75*** (ꢁ28)
192.33 ꢄ 17.72* (ꢁ11)
194.49 ꢄ 19.04* (ꢁ10)
196.66 ꢄ 15.23 (ꢁ9)
13.21 ꢄ 1.26c (ꢁ23)
15.32 ꢄ 1.11* (þ16)
14.79 ꢄ 1.28* (þ12)
15.45 ꢄ 1.09* (þ17)
15.05 ꢄ 1.44* (þ14)
15.19 ꢄ 1.32* (þ15)
NS
162.10 ꢄ 13.35* (ꢁ12)
13.77 ꢄ 1.20
13.75 ꢄ 1.26
(þ4)
(þ4)
NS
NS
167.63 ꢄ 11.94
(ꢁ9)
139.99 ꢄ 12.33*** (ꢁ24)
171.25 ꢄ 18.01NS (ꢁ7)
132.63 ꢄ 10.76*** (ꢁ28)
163.94 ꢄ 14.16* (ꢁ11)
165.78 ꢄ 12.86* (ꢁ10)
159.29 ꢄ 10.66*** (ꢁ23)
15.32 ꢄ 1.41* (þ16)
NS
NS
190.11 ꢄ 18.16
(ꢁ8)
13.87 ꢄ 1.18
(þ5)
146.88 ꢄ 11.23*** (ꢁ29)
15.58 ꢄ 1.18* (þ18)
NS
186.19 ꢄ 17.12* (ꢁ10)
14.39 ꢄ 1.11
14.37 ꢄ 1.09
(þ9)
(þ9)
NS
NS
187.91 ꢄ 12.93
(ꢁ9)
169.47 ꢄ 12.83 (ꢁ8)
190.32 ꢄ 13.86 (ꢁ8)
14.26 ꢄ 1.29 (þ8)
NS
NS
167.63 ꢄ 11.94
176.84 ꢄ 16.38
(ꢁ9)
(ꢁ4)
186.19 ꢄ 14.57* (ꢁ10)
193.81 ꢄ 16.86* (ꢁ10)
207.46 ꢄ 18.69 NS (ꢁ4)
196.66 ꢄ 15.23 (ꢁ9)
13.75 ꢄ 1.26
13.47 ꢄ 1.31
(þ4)
NS
NS
NS
4o
4p
4q
4r
194.46 ꢄ 19.02
(ꢁ6)
(þ2)
169.47 ꢄ 12.83 (ꢁ8)
190.32 ꢄ 13.86 (ꢁ8)
14.26 ꢄ 1.29 (þ8)
143.68 ꢄ 8.82** (ꢁ22)
161.36 ꢄ 9.58** (ꢁ22)
172.88 ꢄ 10.43** (ꢁ20)
198.82 ꢄ 16.62 NS (ꢁ8)
194.49 ꢄ 15.37* (ꢁ10)
142.63 ꢄ 12.26*** (ꢁ34)
15.19 ꢄ 1.28* (þ15)
NS
NS
NS
171.31 ꢄ 17.08
(ꢁ7)
190.32 ꢄ 18.18
(ꢁ8)
13.73 ꢄ 1.22
13.71 ꢄ 1.22
(þ4)
(þ4)
NS
4s
162.10 ꢄ 14.58* (ꢁ12)
121.57 ꢄ 10.82*** (ꢁ34)
184.12 ꢄ 12.72* (ꢁ11)
134.47 ꢄ 12.81*** (ꢁ35)
Gemfibrozil
15.85 ꢄ 1.27** (þ20)
***P < 0.001; **P < 0.01; *P < 0.05; NS ¼ Non significant. The lipid lowering activity of Benzofuranebisindole hybrids (100 mg/kg) in Triton treated hyperlipidemic rats. Triton
treated group is compared with control and drug treated group is compared with triton group.
a
mg/dl.
b
n mol of free fatty acids formed/h/ml of plasma; values are mean ꢄ SD of six rats.
4.2. Effect of compounds 4a, 4c, 4h and 4j on lipid lowering at
the superoxide ions by 33% and 31%, hydroxyl radical’s by 30% and
different doses in triton induced hyperlipidemic rat
27% and microsomal lipid peroxidation by 31% and 32%, respectively.
The standard drug Alloperinol, at 200
mg/mL, showed 51% inhibition
After the confirmation of the most active hybrids in primary
screening we further, evaluated the activity of compounds 4a, 4c,
4h and 4j at different doses at 50e150 mg/kg body weight. Among
the four potent compounds, the compound 4j lowered the TC by
22%e29%, PL by 20%e29%, and TG by 20%e30% respectively in dose
dependent manner (Fig. 2.) The synthesized derivatives inhibited
cholesterol biosynthesis and enhanced the activity of lipolytic en-
zymes to early clearance of lipids from circulation in triton induced
hyperlipidemia.
in superoxide ions, whereas Mannitol and
a
-tocopherol, at the same
dose, showed 49% and 52% inhibition of hydroxyl ions and micro-
somal lipid peroxidation, respectively in in vitro system. The scav-
enging potential of the other derivatives was modest at best.
Interestingly, in terms of structure activity relationship, among
the series of benzofuranebisindole hybrids synthesized (4ae4s),
the presence of electron donating groups (methoxy substituted) on
both indole and benzofuran rings (4a, 4c, 4h and 4j) exhibited
potent activity, while the absence of these or its replacement with
electron withdrawing groups resulted in diminished activity, as
evidenced in compounds (4b, 4f, 4g, 4i, 4k, 4l and 4m).
4.3. Effect of compounds 4a, 4c, 4h and 4j on lipoprotein cholesterol
level and LCAT activity in triton induced hyperlipidemic rat
5. Conclusion
The analysis of hyperlipidemic plasma of triton administered
rats showed a significant increase in the level of lipoprotein lipids
and these effects were pronounced for VLDL and LDL followed by a
decrease in HDL as compared to control rats. Pleasingly, the treat-
ment with active compounds 4a, 4c, 4h and 4j significantly
reversed the VLDL, LDL and HDL levels as shown in Fig. 3.
Furthermore, triton administration markedly decreased the level of
LCAT in hyperlipidemic rats, and which on treatment with com-
pounds 4a, 4c, 4h and 4j were found to be significantly increased at
par with the standard drug gemfibrozil (Fig. 4). The role of LCAT
activity in lipoprotein metabolism which contributes to an
increased level of HDL-C in plasma is well known [22].
In conclusion, the pathological investigation has revealed that
the novel hybrids 4a, 4c, 4h and 4j have significant anti-
hyperlipidemic activity and they decreased the total cholesterol
(TC), phospholipids (PL) and triglycerides (TG) in plasma of
hyperlipidemic rats. In parallel, the treatment with active hybrids
effectively reversed the levels of VLDL, LDL and HDL and also
increased the LCAT activity, which plays a key role in lipoprotein
metabolism contributing to an increased level of HDL-C in plasma.
Furthermore, the synthesized hybrids compounds 4a and 4j
exhibited potent antioxidant properties. Thus, taken together our
findings strongly suggest that these novel hybrid prototypes (with
unique chemical structures) improve lipid abnormalities and would
be a potential new leads against dyslipidemia.
4.4. Effect of compounds 4ae4s on superoxide anions, hydroxyl
radicals and lipid-peroxidation
6. Experimental
Antioxidant activities of compounds 4ae4s at 200
mg/mL were
evaluated by generating free radicals [superoxide ions (O2.ꢁ), hy-
droxyl radicals (,OH), microsomal lipid peroxidation] in vitro in the
absence and presence of these compounds. The results of this study
are shown in Fig. 5. Compounds 4a and 4j significantly suppressed
6.1. General information
All reagents were commercial and were used without further
purification. Chromatography was carried on silica gel (60e120 and

42
K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
Fig. 2. Percentage (%) change of plasma lipids with the treatment of compounds 4a, 4c, 4h and 4j in triton-induced hyperlipidemic rats at the different doses. Each parameter
represents pooled data from 6 rats/group and values are expressed as mean ꢄ S.D. ***P < 0.001, **P < 0.01, *P < 0.05 compared b/w triton and triton plus compound treated different
doses. (50, 100 and 150 mg/kg b.wt).
100e200 mesh). All reactions were monitored by TLC; silica gel
plates with fluorescence F254 were used. Melting points were
uncorrected. The 1H NMR, 2D-NMR (COSY, HMBC, HSQC) and 13C
NMR spectra were determined on 200, 300, MHz and 50, 75, MHz,
respectively, using CDCl3 and DMSO- d6 as solvents and TMS as
internal standard. All chemical shifts were given in ppm. IR spectra
were recorded on in the range of 500e4000 cmꢁ1, and multiplicity
(s ¼ singlet, brs ¼ broad singlet, d ¼ doublet, brd ¼ broad doublet,
dd ¼ double doublet, t ¼ triplet, q ¼ quartet, m ¼ multiplet).
6.3. General synthetic procedure for preparation of 4-hydroxy-5-
alkyl isophthalaldehydes. (2aef)
2-Alkyl phenol (1.0 equiv.) and hexamethylenetetramine
(1.2 equiv.) were dissolved in TFA (25 mL) and the solution was
heated at 120 ꢂC for 3 h. After cooling to room temperature 10% aq.
H2SO4 (25 mL) was added and again the temperature maintained
(at 90e100 ꢂC) for two more hours. The solution was basified with
NaHCO3 to pH 8 and extracted 3-fold with 50 mL of CHCl3. The
combined organic layers were dried on Na2SO4, filtered, and
6.2. Starting materials (1aef)
Starting materials (1aef) were commercially available and were
used without further purification.
Fig. 3. Effect of compounds 4a, 4c, 4h and 4j (100 mg/kg) improves the lipoprotein
cholesterol level in triton induced hyperlipidemic rats. Each parameter represents
pooled data from 6 rats/group and values are expressed as mean ꢄ S.D. ***P < 0.001
compared between control and triton treated rats group only, bP < 0.01; cP < 0.001
between triton and triton plus compounds treated groups, gemfibrozil is taken as
standard drug.
Fig. 4. Compounds 4a, 4c, 4h and 4j (100 mg/kg) re-activate LCAT activity in triton
induced hyperlipidemic rats. Each parameter represents pooled data from 6 rats/group
and values are expressed as mean ꢄ S.D. ***P < 0.001 between control and triton
treated rats group only, aP < 0.05; bP < 0.01 between triton and triton plus compounds
treated groups, gemfibrozil is taken as standard drug.

K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
43
Fig. 5. The effect of benzofuranebisindole hybrids (200 mg/ml) on superoxide ion (nmol. formazone formed/min), hydroxyl ion (nmol. MDA formed/h) and lipid peroxidation in
microsomes (nmol. MDA formed/mg protein) was shown (standard drugs for superoxide anions-alloperinol (200 mg/ml), hydroxyl ions-manitol and for microsomal lipid perox-
idation-
(non significant).
a
-tocopherol (200
m
g/ml) were used. Each value is mean ꢄ SD of six values, *P < 0.05; **P < 0.01; ***P < 0.001 experimental values compared with control values. NOTE: NS
concentrated to dryness under reduced pressure. The crude prod-
uct was purified on a silica gel column (100e200 mesh) using
ethylacetate-hexane (12:88, v/v) as eluent to afford compounds
2aef in good yields.
6.3.5. 4-Hydroxy-5-propylisophthalaldehyde (2e)
Compound 2e was synthesized from 1e, after purification on a
silica gel eluted with ethylacetate-hexane (08:92, v/v), compound 2e
was obtained. Oily; Yield: 62%; IR (neat): 3259, 2872, 1710, 1620,
1010 cmꢁ1; 1H NMR (CDCl3, 400 MHz)
d: 11.85 (s, 1H), 9.96 (s, 1H),
6.3.1. 4-Hydroxy-5-methylisophthalaldehyde (2a)
9.89 (s, 1H), 7.96 (d, J ¼ 2.0 Hz, 1H), 7.91 (d, J ¼ 2.0 Hz, 1H), 2.68 (t,
Compound 2a was synthesized from 1a, after purification on a
silica gel eluted with ethylacetate-hexane (12:88, v/v), compound
2a was obtained. White solid; Yield: 60%; mp: 125e127 ꢂC; IR
J ¼ 6.6 Hz, 2H),1.71e1.61 (m, 2H), 0.96 (t, J ¼ 7.3 Hz, 3H); ESI-MS: m/z:
þ
193 (M þ H)þ; HRMS m/z calcd for C11H12O3 (M þ H) 193.0865,
found 193.0869.
(neat): 3262, 2865, 1703, 1626, 1013 cmꢁ1
;
1H NMR (CDCl3,
300 MHz)
d
: 11.82 (s,1H), 9.97 (s, 1H), 9.90 (s, 1H), 7.97 (d, J ¼ 1.8 Hz,
6.3.6. 5-Chloro-4-hydroxyisophthalaldehyde (2f)
1H), 7.93 (brs, 1H), 2.33 (s, 3H); 13C NMR (CDCl3, 75 MHz): 196.4,
189.9, 165.0, 137.2, 134.8, 128.7, 125.2, 119.7, 15.1; ESI-MS: m/z: 165
(M þ H)þ. HRMS m/z calcd for C9H8O3 (M þ H)þ 165.0552, found
165.0559.
Compound 2f was synthesized from 1f, after purification on a
silica gel eluted with ethylacetate-hexane (15:85, v/v), compound
2f was obtained. White solid; Yield: 70%; IR (neat): 3263, 2880,
1721, 1632, 1013 cmꢁ1 1H NMR (CDCl3, 400 MHz)
; d: 12.05 (s, 1H),
10.00 (s, 1H), 9.91 (s, 1H), 8.15 (d, J ¼ 1.9 Hz, 1H), 8.07 (d, J ¼ 1.9 Hz,
1H); ESI-MS: m/z: 185 (M þ H)þ; HRMS m/z calcd for C8H5ClO3
(M þ H) þ 185.0005, found 185.0011.
6.3.2. 4-Hydroxy-5-isopropylisophthalaldehyde (2b)
Compound 2b was synthesized from 1b, after purification on
a silica gel eluted with ethylacetate-hexane (12:88, v/v), com-
pound 2b was obtained. White solid, yield: 65%; mp: 163e
164 ꢂC; IR (KBr): 3028, 1677, 1665, 1615, 1229, 768 cmꢁ1; 1H NMR
6.4. General synthetic procedure for preparation of 2-(4-chloroben
zoyl)-7-methylbenzofuran-5-carbaldehyde (3a)
(CDCl3, 300 MHz) d: 11.94 (s, 1H), 9.97 (s, 1H), 9.91 (s, 1H), 7.99
(brs, 1H), 7.96 (d, J ¼ 1.47 Hz, 1H), 3.43e3.33 (m, 1H), 1.27 (d,
To a mixture of 4-hydroxy-5-methylisophthalaldehyde (2a) (1.0 g,
6.09 mmol), 4-chlorophenacylbromide (1.6 g, 7.31 mmol) and K2CO3
(0.8 g, 6.08 mmol), acetonitrile (20 mL) was added. The reaction
mixture was refluxed for 3 h. After completion of the reaction, K2CO3
was removed in a sintered funnel, and the filtrate was concentrated
under vacuum and subjected to column chromatography with EtOA-
c:Hexane (10:90, v/v) to give pure 3a as a pale yellow colored solid.
The compounds (3aem) were prepared in a manner similar to
the procedure described above.
J ¼ 5.19 HZ, 6H); 13C NMR (CDCl3, 75 MHz) : 196.6, 189.9, 164.3,
138.9, 134.8, 133.2, 129.0, 119.9, 26.5, 22.1; ESI-MS: m/z: 193
þ
(M þ H)þ. HRMS m/z calcd for C11H12O3 (M þ H)
193.0865,
found 193.0861.
6.3.3. 5-Tert-butyl-4-hydroxyisophthalaldehyde (2c)
Compound 2c was synthesized from 1c, after purification on a
silica gel eluted with ethylacetate-hexane (10:90, v/v), compound
2c was obtained.. Oily; Yield: 65%; IR (neat): 3252, 2865,1703,1626,
1013 cmꢁ1; 1H NMR (CDCl3, 300 MHz)
d
: 12.39 (s, 1H), 9.99 (s, 1H),
6.4.1. 2-(4-Chlorobenzoyl)-7-methylbenzofuran-5-carbaldehyde (3a)
Compound 3a was synthesized from 2a, after purification on a
silica gel eluted with ethylacetate-hexane (10:90, v/v), compound
3a was obtained. Pale yellow solid, yield; 85%; mp 168e169 ꢂC; IR
9.93 (s, 1H), 8.07 (brs, 1H), 7.99 (brs, 1H), 1.46 (s, 9H); 13C NMR
(CDCl3, 75 MHz); 196.4, 190.0, 166.1, 140, 135.4, 133.9, 128.6, 120.4,
35.2, 29.1; ESI-MS: m/z: 207 (M þ H)þ; HRMS m/z calcd for C12H14O3
(M þ H) þ 207.1021, found 207.1018.
(KBr); 3020, 1691, 1646, 1600, 1217, 777 cmꢁ1 1H NMR (CDCl3,
;
300 MHz)
d
; 10.04 (s,1H), 8.09 (s,1H), 8.03 (d, J ¼ 8.6 Hz, 2H), 7.86 (s,
6.3.4. 5-Ethyl-4-hydroxyisophthalaldehyde (2d)
1H), 7.63 (s,1H), 7.53 (d, J ¼ 8.6 Hz, 2H), 2.65 (s, 3H); 13C NMR (CDCl3,
75 MHz); 191.4, 182.5, 158.2, 153.3, 139.8, 135.0, 133.4, 131.0, 129.1,
128.9, 126.8, 124.9, 124.1,116.7, 15.2; ESI-MS (m/z) 299 (M þ H)þ;
HRMS m/z calcd for C17H11ClO3 (M þ H)þ 299.0475, found 299.0461.
Compound 2d was synthesized from 1d, after purification on a
silica gel eluted with ethylacetate-hexane (12:89, v/v), compound
2d was obtained. White solid, yield: 69%; mp: 173e174 ꢂC; IR
(neat): 3259, 2870, 1700, 1628, 1013 cmꢁ1
;
1H NMR (CDCl3,
400 MHz)
d
: 11.85 (s, 1H), 9.98 (s, 1H), 9.91 (s, 1H), 7.97e7.95 (m,
6.4.2. 7-Methyl-2-(4-methylbenzoyl) benzofuran-5-carbaldehyde
(3j)
Compound 3j was synthesized from 2j, after purification on a
silica gel eluted with ethylacetate-hexane (15:85, v/v), compound
2H), 2.78e2.72 (m, 2H), 1.26 (t, J ¼ 7.5 Hz, 3H); ESI-MS: m/z: 179
(M þ H)þ; HRMS m/z calcd for C10H10O3 (M þ H) þ 179.0708, found
179.0711.

44
K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
3j was obtained. Pale yellow solid, yield; 80%; mp 165e166 ꢂC; IR
(KBr): 3043, 1684, 1659, 1629, 1204, 755 cmꢁ1 1H NMR (CDCl3,
300 MHz)
(M þ H)þ; Anal Calcd for C39H36N2O5: C, 76.45; H, 5.92; N, 4.57;
;
Found: C, 76.51; H, 5.98; N, 4.62.
d
; 10.05 (s,1H), 8.08 (s,1H), 7.99 (d, J ¼ 8.1 H, 2Hz), 7.84 (s,
1H), 7.60 (s, 1H), 7.35 (d, J ¼ 8.1 Hz, 2H), 2.66 (s, 3H), 2.47(s, 3H); 13C
NMR (CDCl3, 75 MHz): 191.4, 183.5, 158.2, 153.8, 144.3, 134.2, 133.3,
128.7, 126.9, 124.8, 124.1, 116.3, 21.8, 15.2; ESI-MS: (m/z) 279
(M þ H)þ; HRMS m/z calcd for C18H14O3 (M þ H)þ 279.1021, found
279.1017.
6.5.4. (4-Chlorophenyl)(5-(di(1H-indol-3-yl)methyl)-7-ethylbenzo
furan-2-yl)methanone (4d)
Compound 4d was synthesized from 3d, after purification on a
silica gel eluted with hexane ethylacetate-hexane (20:80, v/v),
compound 4d was obtained. yellow solid; yield: 84%; mp: 190e
191 ꢂC; IR(KBr, cmꢁ1): 3414, 3013, 2143, 1639, 1219, 770; 1H NMR
6.5. General synthetic procedure for preparation of (5-(bis(5-methoxy-
1H-indol-3-yl)methyl)-7-methylbenzofuran-2-yl)(4-methoxyphenyl)
methanone (4a)
(DMSO-d6, 300 MHz)
d
: 10.87 (s, 2H), 7.86 (d, J ¼ 7.8 Hz, 2H), 7.76 (s,
1H), 7.66 (d, J ¼ 7.8 Hz, 2H), 7.58 (s, 2H), 7.54 (s, 2H), 7.40e7.32 (m,
4H), 7.07 (t, J ¼ 6.3 Hz, 2H), 6.92e6.87 (m, 4H), 6.00 (s, 1H), 2.92 (d,
J ¼ 7.0 Hz, 2H),1.31 (d, J ¼ 7.0 Hz, 3H); 13C NMR (DMSO-d6, 75 MHz);
182.7, 153.3, 151.6, 141.9, 138.3, 137.1, 136.0, 131.5, 129.4, 129.2, 127.9,
127.1, 126.9, 124.2, 121.4, 120.5, 119.6, 118.7, 118.6, 118.3, 111.9, 22.9,
14.4. ESI-MS: m/z: 530 (M þ H)þ; Anal Calcd for C34H25ClN2O2: C,
77.19; H, 4.76; N, 5.30; Found: C, 77.17; H, 4.73; N, 5.28.
A mixture of ethyl 2-(4-chlorobenzoyl)-7-methylbenzofuran-5-
carbaldehyde (3a) (1.0 g, 3.4 mmol), 5-methoxyindole (0.9 g,
6.8 mmol), and I2 (17.21 mg, 0.21 mmol) in acetonitrile (20 mL) was
stirred at room temperature for 30 min. After completion of the
reaction, the mixture treated with aq. Na2S2O3 solution (5%, 10 mL)
and the product was extracted with CHCl3 (3 ꢃ 25 mL). The com-
bined organic layers were dried with anhydrous sodium sulfate,
concentrated in vacuo, and purified by column chromatography to
afford 4a.
6.5.5. (5-(Bis (5-methoxy-1H-indol-3-yl) methyl)-7-chlorobenzo
furan-2-yl) (4-methoxy phenyl)methanone (4e)
Compound 4e was synthesized from 3e, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4e was obtained. Yellow solid; yield: 84%; mp: 130e131 ꢂC; IR(KBr,
The compounds (4aes) were prepared in a manner similar to
the procedure described above.
cmꢁ1): 3424, 3014,1635,1216, 769; 1H NMR (DMSO-d6, 300 MHz)
d:
10.78 (s, 2H), 8.10 (d, J ¼ 8.8 Hz, 2H), 7.84 (s, 1H), 7.77 (s, 1H), 7.69 (s,
1H), 7.30 (d, J ¼ 8.7 Hz, 2H), 7.15 (d, J ¼ 8.8 Hz, 2H), 6.93 (d, J ¼ 2 Hz,
2H), 6.83 (d, J ¼ 2.0 Hz, 2H), 6.78e6.74 (m, 2H), 6.00 (s, 1H), 3.91 (s,
3H), 3.65 (s, 6H) ESI-MS: m/z: 591 (M þ H)þ; Anal Calcd for
C35H27ClN2O5: C, 71.12; H, 4.60; N, 4.74; Found: C, 71.17; H, 4.67;
N, 4.71.
6.5.1. (5-(Bis(5-methoxy-1H-indol-3-yl)methyl)-7-methylbenzofuran-
2-yl)(4-methoxyphenyl) methanone (4a)
Compound 4a was synthesized from 3a, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4a was obtained. Yellow solid; yield: 84%; mp: 179e180 ꢂC; IR(KBr,
cmꢁ1): 3413, 3019, 1631, 1259, 1216, 770; 1H NMR (DMSO-d6,
300 MHz)
d
: 10.71 (s, 2H), 8.08 (d, J ¼ 8.1 Hz, 2H), 7.72 (s,1H), 7.58 (s,
6.5.6. (4-Chlorophenyl)(5-(di(1H-indol-3-yl)methyl)-7-isopropyl
benzofuran-2-yl)methanone (4f)
1H), 7.46 (s, 1H), 7.30e7.13 (m, 4H), 6.87e6.73 (m, 6H), 5.90 (s, 1H),
3.91 (s, 3H), 3.63 (s, 6H), 2.54 (s, 3H); 13C NMR (DMSO-d6, 50 MHz);
181.7, 163.1, 153.0, 152.6, 151.7, 141.1, 131.8, 131.6, 130.0, 129.3, 126.1,
124.4, 121.1, 126.17, 124.4, 121.1, 119.6, 117.7, 116.5, 113.9, 112.0,
110.5, 101.4, 55.2, 14.8. ESI-MS: m/z: 571 (M þ H)þ; Anal Calcd
for C36H30N2O5: C, 75.77; H, 5.30; N, 4.91; Found: C, 75.79; H, 5.37;
N, 4.89.
Compound 4f was synthesized from 3f, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4f was obtained. Yellow solid; yield: 84%; mp: 170e171 ꢂC; IR(KBr,
cmꢁ1): 3412, 3011,1630, 770; 1H NMR (DMSO-d6, 300 MHz)
d: 10.84
(s, 2H), 8.04 (d, J ¼ 7.8 Hz, 2H), 7.76e7.58 (m, 5H), 7.40e7.32 (m,
4H), 7.08 (t, J ¼ 6.0 Hz, 2H), 6.91e6.87 (m, 4H), 6.01 (s, 1H), 3.34 (m,
1H), 1.36 (d, J ¼ 6.0 Hz, 6H); 13C NMR (DMSO-d6, 75 MHz); 182.7,
152.7, 151.6, 141.9, 138.3, 137.1, 136.0, 132.4, 129.2, 127.4, 127.1, 127.0,
124.4, 121.4, 119.6, 118.7, 118.6, 118.3, 111.9, 22.9, 22.8. ESI-MS: m/z:
543 (M þ H)þ; Anal Calcd for C35H27ClN2O2: C, 77.41; H, 5.01; N,
5.16; Found: C, 77.48; H, 5.07; N, 5.14.
6.5.2. (5-(Di(1H-indol-3-yl)methyl)-7-isopropylbenzofuran-2-yl)(4-
methoxyphenyl)methanone (4b)
Compound 4b was synthesized from 3b, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4b was obtained. Yellow solid; yield: 72%; mp: 182e183 ꢂC;
IR(KBr,cmꢁ1): 3413, 3016, 2922, 1629, 768; 1H NMR (DMSO-d6,
6.5.7. 4-(5-(Di (1H-indol-3-yl) methyl)-7-isopropylbenzofuran-2-
carbonyl)benzonitrile (4g)
Compound 4g was synthesized from 3g, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4g was obtained. Yellow solid; yield: 84%; mp: 168e169 ꢂC; IR(KBr,
cmꢁ1): 3410, 3018, 2965, 1645, 1548, 1457, 1096, 767; 1H NMR
300 MHz)
d
: 10.83 (s, 2H), 8.07 (d, J ¼ 8.1 Hz, 2H), 7.69 (s, 1H), 7.56
(s, 2H), 7.40e7.32 (m, 4H), 7.15e7.04 (m, 4H), 6.92e6.87 (m, 4H),
6.01 (s, 1H), 3.90 (s, 3H), 3.33 (s, 1H), 1.36 (d, J ¼ 6.3 Hz, 6H); 13C
NMR (DMSO-d6, 75 MHz); 182.3, 163.7, 152.5, 152.3, 141.7, 137.1,
132.4, 132.2, 129.9, 127.1, 126.9, 124.2, 121.4, 120.3, 119.6, 118.8, 118.7,
116.8, 114.5, 111.9, 56.0, 29.2, 22.9. ESI-MS: m/z: 539 (M þ H)þ; Anal
Calcd for C36H30N2O3: C, 80.27; H, 5.61; N, 5.20; Found: C, 80.24; H,
5.59; N, 5.24.
(DMSO-d6, 300 MHz)
d
: 10.83 (s, 2H), 8.07 (d, J ¼ 9.5 Hz, 4H),7.75 (s,
1H), 7.55 (d, J ¼ 7.4 Hz, 2H), 7.36e7.28 (m, 4H), 7.03 (m, J ¼ 6.5 Hz,
2H), 6.88e6.83 (m, 4H), 5.98 (s, 1H), 3.35 (s, 1H), 1.32 (d, J ¼ 6.2 Hz,
6H); 13C NMR (DMSO-d6, 75 MHz); 182.8, 153.0, 151.3, 142.0, 141.1,
137.1, 133.1, 132.5, 130.2, 127.8, 127.1, 124.1, 121.4, 120.7, 119.1, 118.7,
115.3, 112.0, 29.1, 22.8; ESI-MS: m/z: 534 (M þ H)þ; Anal Calcd for
C36H27N3O2: C, 81.03; H, 5.10; N, 7.87; Found: C, 81.08; H, 5.14;
N, 7.90.
6.5.3. (5-(Bis(5-methoxy-1H-indol-3-yl)methyl)-7-tert-butylbenzo
furan-2-yl)(4-methoxy phenyl) methanone (4c)
Compound 4c was synthesized from 3c, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4c was obtained. Yellow solid; yield: 84%; mp: 175e176 ꢂC; IR(KBr,
cmꢁ1): 3429, 3018,1634,1218, 765; 1H NMR (DMSO-d6, 300 MHz)
d:
6.5.8. (5-(Bis (5-methoxy-1H-indol-3-yl) methyl)-7-propylbenzo
furan-2-yl) (4-methoxyphenyl) methanone (4h)
Compound 4h was synthesized from 3h, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4h was obtained. Yellow solid; yield: 84%; mp: 175e176 ꢂC; IR(KBr,
10.71 (s, 2H), 8.05 (d, J ¼ 8.0 Hz, 2H), 7.72 (s, 1H), 7.62 (d, J ¼ 4.7 Hz,
2H), 7.29 (d, J ¼ 8.7 Hz, 2H), 7.14 (d, J ¼ 8.7 Hz, 2H), 6.90 (d,
J ¼ 2.0 Hz, 2H), 6.81 (d, J ¼ 2.0 Hz, 2H), 6.76e6.72 (m, 2H), 5.94 (s,
1H), 3.90 (s, 3H), 3.62 (s, 6H), 1.50 (s, 9H). ESI-MS: m/z: 613

K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
45
cmꢁ1): 3410, 3018, 2965, 1645, 1548, 1457, 1096, 769; 1H NMR
(DMSO-d6, 300 MHz)
: 10.71 (s, 2H), 8.06 (d, J ¼ 8.8 Hz, 2H), 7.71 (s,
6.5.13. (5-(Di (1H-indol-3-yl) methyl)-7-methylbenzofuran-2-yl)
(p-tolyl) methanone (4m)
d
1H), 7.60 (d, J ¼ 1.4 Hz, 1H), 7.49 (d, J ¼ 1.4 Hz, 1H), 7.30 (s,1H), 7.28
(s,1H), 7.14 (d, J ¼ 8.8 Hz, 2H), 6.87 (d, J ¼ 2.3 Hz, 2H), 6.80 (d,
J ¼ 2.3 Hz, 2H), 6.76e6.72 (m, 2H), 5.92 (s, 1H), 3.90 (s, 3H), 3.62 (s,
6H), 2.89 (t, J ¼ 6.0 Hz, 2H),1.80e1.72 (m, 2H), 0.94(t, J ¼ 7.4 Hz, 3H);
13C NMR (DMSO-d6, 75 MHz); 182.3, 141.6, 132.4, 129.9, 127.5, 126.9,
126.1, 124.9, 120.5118.4, 116.9, 114.5, 112.6, 111.1, 102.0, 56.0, 55.8,
31.7, 22.9, 14.1. ESI-MS: m/z: 599 (M þ H)þ; Anal Calcd for
C38H34N2O5: C, 76.23; H, 5.72; N, 4.68; Found: C, 76.18; H, 5.70;
N, 4.65.
Compound 4m was synthesized from 3m, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4m was obtained. Yellow solid; yield: 84%; mp: 130e131 ꢂC; IR(KBr,
cmꢁ1): 3413,3012, 2142, 1636, 766; 1H NMR (DMSO-d6, 300 MHz)
d:
10.88 (s, 2H), 7.94 (d, J ¼ 7.3 Hz, 2H), 7.71 (s, 1H), 7.58 (s, 1H), 7.48e
7.33 (m, 6H), 7.07 (s, 2H), 6.92e6.87 (m, 4H), 5.98 (s, 1H), 2.54 (s,
3H), 2.45 (s, 3H); 13C NMR (DMSO-d6, 50 MHz); 182.9, 153.1, 151.5,
143.4, 141.1, 136.6, 134.2, 130.2, 129.2, 126.5, 126.2, 123.7, 121.2,
120.9, 119.0, 118.1, 117.2, 111.4, 21.12, 14.8; ESI-MS: m/z: 495
(M þ H)þ; Anal Calcd for C34H26N2O2: C, 82.57; H, 5.30; N, 5.66;
Found: C, 82.52; H, 5.28; N, 5.61.
6.5.9. 4-(5-(Di (1H-indol-3-yl) methyl)-7-methylbenzofuran-2-
carbonyl) benzonitrile (4i)
Compound 4i was synthesized from 3i, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), com-
pound 4i was obtained. Yellow solid; yield: 84%; mp: 180e
181 ꢂC; IR(KBr, cmꢁ1): 3412, 3015, 1643, 1219, 770; 1H NMR
6.5.14. (5-(Bis(5-nitro-1H-indol-3-yl)methyl)-7-isopropylbenzo
furan-2-yl)(4-methoxyphenyl) methanone (4n)
Compound 4n was synthesized from 3b, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4n was obtained. Yellow solid; yield: 84%; mp: 137e138 ꢂC; IR(KBr,
cmꢁ1): 3409, 3021, 2966, 1218, 1030, 765; 1H NMR (DMSO-d6,
(DMSO-d6, 300 MHz) d: 10.88 (s, 2H), 8.12e8.09 (m, 4H), 7.78 (s,
1H), 7.58 (s, 1H), 7.51 (s, 1H), 7.40e7.32 (m, 4H), 7.09e7.05 (m,
2H), 6.91e6.87 (m, 4H), 5.98 (s, 1H), 2.53 (s, 3H); 13C NMR
(DMSO-d6, 75 MHz); 182.8154.0, 151.3, 141.9, 141.0, 137.1, 133.1,
131.3, 130.2, 127.0, 126.7, 124.2, 121.4, 120.5, 119.5, 119.3, 118.7,
118.5, 115.3, 111.9, 15.3; ESI-MS: m/z: 506 (M þ H)þ; Anal Calcd for
C34H23N3O2: C, 80.77; H, 4.59; N, 8.31; Found: C, 80.81; H, 4.63;
N, 8.36.
300 MHz) d: 11.70 (s, 2H), 8.38 (s, 2H), 8.09e8.00 (m, 4H), 7.72 (s,
1H), 7.64e7.57 (m, 4H), 7.21e7.13 (m, 4H), 6.39 (s, 1H), 3.90 (s, 3H),
3.44e3.41 (m, 1H), 1.38 (d, J ¼ 6.2 Hz, 6H); 13C NMR (DMSO-d6,
50 MHz); 182.7, 163.2, 152.1, 151.9, 140.2, 139.9, 139.8, 132.3, 131.6,
129.2, 127.6, 126.9, 126.0, 125.7, 120.7, 119.9, 116.6, 116.2, 113.9, 112.1,
55.5, 28.5, 22.3; ESI-MS: m/z: 630 (M þ H)þ; Anal Calcd for
C36H28N4O7: C, 68.78; H, 4.49; N, 8.91; Found: C, 68.79; H, 4.51;
N, 8.94.
6.5.10. (5-(Bis (5-methoxy-1H-indol-3-yl) methyl)-7-ethylbenzo
furan-2-yl) (4-methoxyphenyl) methanone (4j)
Compound 4j was synthesized from 3j, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4j was obtained. Yellow solid; yield: 84%; mp: 177e178 ꢂC; IR(KBr,
6.5.15. (5-(Bis(5-nitro-1H-indol-3-yl)methyl)-7-ethylbenzofuran-
2-yl)(4-methoxyphenyl)methanone (4o)
Compound 4o was synthesized from 3j, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4o was obtained. Yellow solid; yield: 84%; mp: 178e179 ꢂC; IR(KBr,
cmꢁ1): 3429, 3019, 2954, 1633, 1512, 772; 1H NMR (DMSO-d6,
cmꢁ1): 3418, 3015, 1633, 1219, 771; 1H NMR (DMSO-d6, 300 MHz)
d:
10.71 (s, 2H), 8.07 (d, J ¼ 8.8 Hz, 2H), 7.72 (s, 1H), 7.58 (s, 1H), 7.52 (s,
1H), 7.28 (d, J ¼ 8.7 Hz, 2H), 7.15 (d, J ¼ 8.8 Hz, 2H), 6.87 (d,
J ¼ 3.0 Hz, 2H), 6.75 (d, J ¼ 3.0 Hz, 3H), 6.76e6.72 (m, 2H), 5.91 (s,
1H), 3.90 (s, 3H), 3.62 (s, 6H), 2.97e2.90 (m, 2H), 1.29 (d, J ¼ 1.2Hz,
3H); 13C NMR (DMSO-d6, 75 MHz); 182.3, 132.4, 132.2, 129.9, 128.9,
127.8, 127.5, 126.9, 124.9, 120.4, 118.4, 116.9, 114.6, 112.6, 111.1, 102.0,
56.1, 55.8, 22.9, 14.6; ESI-MS: m/z: 585 (M þ H)þ; Anal Calcd for
C37H32N2O5: C, 76.01; H, 5.52; N, 4.79; Found: C, 76.04; H, 5.57;
N, 4.82.
300 MHz) d: 11.71 (s, 2H), 8.39 (s, 2H), 8.08e8.00 (m, 4H), 7.73 (s,
1H), 7.60e7.57 (m, 4H), 7.19e7.13 (m, 4H), 6.39 (s, 1H), 3.90 (s, 3H),
2.95 (d, J ¼ 7.0 Hz, 2H), 1.33 (t, J ¼ 6.0 Hz, 3H); 13C NMR (DMSO-d6,
50 MHz); 181.7, 163.1, 152.7, 151.9, 140.2, 139.9, 139.8, 131.6, 129.2,
128.0, 127.7, 126.7, 125.7, 120.7, 119.9, 116.6, 116.2, 113.9, 112.1, 55.5,
22.4,13.9; ESI-MS: m/z: 615 (M þ H)þ; Anal Calcd for C35H26N4O7: C,
68.40; H, 4.26; N, 9.12; Found: C, 68.44; H, 4.28; N, 9.16.
6.5.11. (4-Chlorophenyl) (5-(di (1H-indol-3-yl) methyl)-7-methyl
benzofuran-2-yl) methanone (4k)
6.5.16. (5-(Di(1H-indol-3-yl)methyl)-7-ethylbenzofuran-2-yl)(4-
methoxyphenyl)methanone (4p)
Compound 4k was synthesized from 3k, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4k was obtained. Yellow solid; yield: 84%; mp: 168e169 ꢂC; IR(KBr,
Compound 4p was synthesized from 3j, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4p was obtained. Yellow solid; yield: 84%; mp: 165e166 ꢂC; IR(KBr,
cmꢁ1): 3419, 3015, 2916, 1253, 768; 1H NMR (DMSO-d6, 300 MHz)
cmꢁ1): 3435, 3017, 1636, 1219, 774; 1H NMR (DMSO-d6, 300 MHz)
d:
10.86 (s, 2H), 8.04 (d, J ¼ 7.8 Hz, 2H), 7.76e7.66 (m, 3H), 7.58 (s, 1H),
7.50 (s, 1H), 7.36 (m, 4H), 7.04 (t, J ¼ 6.6 Hz, 2H), 6.93 (m, 4H), 5.99
(s, 1H), 2.54 (s, 3H); ESI-MS: m/z: 516 (M þ H)þ; Anal Calcd for
C33H23ClN2O2: C, 76.96; H, 4.50; N, 5.44; Found: C, 76.99; H, 4.54;
N, 5.42.
d
: 10.8 (s, 2H), 8.00 (d, J ¼ 8.7 Hz, 2H), 7.69 (s, 1H), 7.57 (s, 1H), 7.51
(s, 1H), 7.40e7.33 (m, 4H), 7.15e7.05 (m, 4H), 6.92e6.87 (m, 4H),
6.00 (s,1H), 3.90 (s, 3H), 2.96e2.89 (m, 2H),1.26 (m,3H); ESI-MS: m/
z: 525 (M þ H)þ; Anal Calcd for C35H28N2O3: C, 80.13; H, 5.38; N,
5.34; Found: C, 80.16; H, 5.39; N, 5.36.
6.5.12. (7-Tert-butyl-5-(di(1H-indol-3-yl)methyl)benzofuran-2-yl)(4-
chlorophenyl)methanone (4l)
6.5.17. (5-(Bis (5-hydroxy-1H-indol-3-yl) methyl)-7-propylbenzo
uran-2-yl) (4-methoxyphenyl) methanone (4q)
Compound 4l was synthesized from 3l, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4l was obtained. yellow solid; yield: 84%; mp: 158e159 ꢂC; IR(KBr,
cmꢁ1): 3429, 3018, 2950, 1638, 1219, 770; 1H NMR (DMSO-d6,
Compound 4q was synthesized from 3h, after purification on a
silica gel eluted with ethylacetate-hexane (20:80, v/v), compound
4q was obtained. Yellow solid; yield: 84%; mp: 134e135 ꢂC; IR(KBr,
cmꢁ1): 3435, 3019, 1634, 1219, 777; 1H NMR (DMSO-d6, 300 MHz)
300 MHz)
d
: 10.83 (s, 2H), 8.04 (d, J ¼ 7.8 Hz, 2H), 7.77e7.60 (m, 5H),
d
: 10.53 (s, 2H), 8.52 (s, 2H), 8.08 (d, J ¼ 8.8 Hz, 2H), 7.72 (s, 1H), 7.53
7.40e7.32 (m, 4H), 7.07e6.87 (m, 6H), 6.02 (s, 1H), 1.47 (s, 9H); ESI-
MS: m/z: 558 (M þ H)þ; Anal Calcd for C36H29ClN2O2: C, 77.62; H,
5.25; N, 5.03; Found: C, 77.67; H, 5.29; N, 5.09.
(d, J ¼ 1.3 Hz, 1H), 7.44 (d, J ¼ 1.1 Hz, 1H), 7.19e7.14 (m, 4H), 6.69e
6.65 (m, 4H), 6.61e6.58 (m, 2H), 5.74 (s, 1H), 3.91 (s, 3H), 2.94e2.77
(m, 2H), 1.81e1.73 (m, 2H), 0.97 (t, J ¼ 7.2 Hz, 3H); ESI-MS: m/z: 571

46
K.V. Sashidhara et al. / European Journal of Medicinal Chemistry 68 (2013) 38e46
(M þ H)þ; Anal Calcd for C36H30N2O5: C, 75.77; H, 5.30; N, 4.91;
References
Found: C, 75.79; H, 5.34; N, 4.95.
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Acknowledgments
The authors are grateful to the Director, CDRI, Lucknow, India for
constant encouragement in drug development program, S.P. Singh
for technical support, SAIF for NMR, IR, and Mass spectral data.
R.K.M, K.B.R. and R.S. are thankful to CSIR, New Delhi, India for
financial support. This is CSIR-CDRI communication number 8496.
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Appendix A. Supplementary data
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Supplementary data related to this article can be found at
http://dx.doi.org/10.1016/j.ejmech.2013.07.009.