Synthesis of Novel Alkyl Amide Functionalized Trifluoromethyl Substituted Furo/thieno Pyridine Derivatives: Their Anticancer Activity and CoMFA and CoMSIA Studies

Article abstract of DOI:10.1002/jhet.3578

A series of novel alkyl amide functionalized trifluoromethyl substituted furo/thieno pyridine derivatives 4a–h, 5a–d, and 6a–h were prepared starting from 2-oxo/thioxo-6-phenyl/thien-2-yl-4-(trifluoromethyl)-1,2-dihydropyridine-3-carbonitrile 1 on reactio

Full text of DOI:10.1002/jhet.3578

Month 2019
Synthesis of Novel Alkyl Amide Functionalized Trifluoromethyl
Substituted Furo/thieno Pyridine Derivatives: Their Anticancer Activity
and CoMFA and CoMSIA Studies
Srinu Bhoomandla,a,b Shravan Kumar Gunda, Srawanthi Kotoori, and Phani Raja Kanuparthy
c
b
a
*
aDepartment of Chemistry, Gitam University, Rudraram, Hyderabad, TS 502329, India
bMalla Reddy Institute of Technology and Science, Maisammaguda, Secunderabad, TS 500100, India
cBioinformatics Division, PGRRCDE, Osmania University, Hyderabad, TS 500007, India
*E-mail: phani.kpr@gmail.com
Received August 6, 2018
DOI 10.1002/jhet.3578
Published online 00 Month 2019 in Wiley Online Library (wileyonlinelibrary.com).
A series of novel alkyl amide functionalized trifluoromethyl substituted furo/thieno pyridine derivatives
4a–h, 5a–d, and 6a–h were prepared starting from 2-oxo/thioxo-6-phenyl/thien-2-yl-4-(trifluoromethyl)-
1,2-dihydropyridine-3-carbonitrile 1 on reaction with bromoethylacetate followed by reaction with different
primary aliphatic amines, cyclic secondary amines, or L-amino acids under different set of conditions. All the
synthesized compounds 4a–h, 5a–d, and 6a–h were screened for anticancer activity against four cancer cell
lines such as HeLa—cervical cancer (CCL-2), COLO205—colon cancer (CCL-222), HepG2—liver cancer
(HB-8065), and MCF7—breast cancer (HTB-22). Compounds 4g and 4h are found to have promising anti-
cancer activity at micromolar concentration. CoMFA and CoMSIA methods were applied to derive 3D-
QSAR models for alkyl amide tagged furo/thieno pyridine derivatives as potential anticancer inhibitors.
3D-QSAR models provided a strong basis for future rational design of more active and selective HeLa,
COLO205, HepG2, and MCF-7 cell line inhibitors.
J. Heterocyclic Chem., 00, 00 (2019).
INTRODUCTION
[14], skin diseases [15], and hyperglycemia [16].
Trifluoromethylated drugs such as nilutamide, flutamide,
hydroxyflutamide, and bicalutamide are nonsteroidal
antiandrogens that are widely used for the treatment of
metastatic prostate cancer [17,18]. Recently, it was found
that the trifluoromethyl group [19–21] at a strategic
position of an organic molecule dramatically alters the
properties of molecule in terms of lipid solubility,
oxidative thermal stability, permeability, and oral
bioavailability.
During the past decade, cancer disease continued to be a
worldwide killer [1]. The medicinal chemists have paid
great attention to the development of novel lead molecule
from natural source, and the demand is growing towards
new therapies against cancer. Although chemotherapy is
the mainstay for cancer treatment, the use of available
chemotherapeutics is often limited due to undesirable side
effects. Currently, a number of heterocyclic compounds
are available commercially as anticancer agents. Fused
pyridines are extensively used in neurology, particularly
in the treatment of neurodegenerative disorders such as
Parkinson’s disease [2], antianxiety disorders [3], and
depression [4]. Among all classes of biologically active
heterocyclic compounds, the 5,6-fused ring systems such
as furopyridines and thienopyridines attract in the
development of new pharmaceutical agents and play an
active role in the development of different medicinal
agents [5–8]. These are structurally analogues to indoles
and pyrrolopyridines and play a significant role in
Based on the importance of both the scaffolds
furopyridine and thienopyridine, we assumed and
synthesized
trifluoromethyl
novel
alkyl
amide
furo/thieno
functionalized
pyridine
substituted
derivatives and submitted for anticancer activity against
four cancer cell lines such as HeLa—cervical cancer,
COLO205—colon cancer, HepG2—liver cancer, and
MCF7—breast cancer. Compounds 4g and 4h are found
to have promising anticancer activity at micromolar
concentration.
The 2(1H) pyridine 1 was reacted with 2-bromoethyl
acetate under basic conditions (K2CO3) and obtained
selectively 2-O-ethylacetoxy-3-cyano-4-trifluoro methyl-
6-substituted pyridine derivatives 2. Compounds 2 were
promoting
activity
[9,10].
Furopyridine
and
thienopyridine scaffolds are present in many bioactive
molecules and acted against HIV [11–13], CNS disorders
© 2019 Wiley Periodicals, Inc.

S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
cyclized in DMF using potassium carbonate as base and
obtained furo[2,3-b]pyridine derivatives 3. The reaction
sequence includes selective O-alkylation and then
abstraction of proton by base from an active methylene
followed cyclization onto nitrile carbon. This type of
cyclization is also known as Thorpe–Ziegler cyclization.
Compound 3 was further reacted with different primary
aliphatic amines, cyclic secondary amines, or L-amino
acids under various set of conditions and obtained N-
alkyl acetamide pyrazolo[3,4-b]pyridine 4, secondary
amine ethanone tagged pyrazolo[3,4-b]pyridine 5, and a-
DMSO, K2CO3, 150–160°C, 10–12 h could not give the
product, and the starting material was recovered. It is
attributed to the less basicity of aromatic amines
compared with aliphatic amines. The synthetic sequence
is drawn in Scheme 1, and products are tabulated in
Table 1.
Compounds 4a–h, 5a–d, and 6a–h were screened for
in vitro against four cancer cell lines such as HeLa—
cervical cancer (CCL-2), COLO205—colon cancer
(CCL-222), HepG2—liver cancer (HB-8065), and MCF7
—breast cancer (HTB-22) as A549 (lung cancer, CCL-
185), MCF7 (breast cancer, HTB-22), DU145 (prostate
cancer, HTB-81), and HeLa (cervical cancer, CCL-2)
using MTT assay [22]. IC50 values in micromolar
concentration of the test compounds for 24 h on each cell
line were calculated and presented in Table 2.
amino acid functionalized pyrazolo[3,4-b]pyridine
6
derivatives, respectively. However, reaction of compound
3 with aromatic amines under different set of conditions
such as (i) DMF, K2CO3, 110–120°C, 12–14 h, (ii)
ethanol, Zn dust, sealed tube, 120°C, 10–12 h, and (iii)
Scheme 1. Synthetic route of alkyl amide functionalized trifluoromethyl substituted furo/thieno pyridine derivatives 4a–h, 5a–d, and 6a–h.
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Novel alkyl amide functionalized furo/thieno pyridine derivatives
Table 1
Preparation of alkyl amide functionalized trifluoromethyl substituted furo/thieno pyridine derivatives 4a–h, 5a–d, and 6a–h.
Entry
Compound
R
X
R0
Yield (%)
1.
2.
3.
4.
5.
6.
7.
8.
4a
4b
4c
4d
4e
4f
4g
4h
5a
5b
5c
5d
6a
6b
6c
6d
6e
6f
Phenyl
Phenyl
Thien-2-yl
Thien-2-yl
Phenyl
O
S
O
S
O
S
O
S
O
S
O
S
O
S
O
S
–CH3
–CH3
–CH3
90
87
91
92
89
86
89
84
82
79
85
78
82
79
85
80
86
82
88
80
–CH3
–CH2–C6H5
–CH2–C6H5
–CH2–C6H5
–CH2–C6H5
–CH3
Phenyl
Thien-2-yl
Thien-2-yl
Phenyl
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Phenyl
–CH3
–CH3
–CH3
–CH3
–CH3
–CH3
–CH3
Thien-2-yl
Thien-2-yl
Phenyl
Phenyl
Thien-2-yl
Thien-2-yl
Phenyl
Phenyl
Thien-2-yl
Thien-2-yl
O
S
O
S
–CH2–C6H5
–CH2–C6H5
–CH2–C6H5
–CH2–C6H5
6g
6h
All the compounds except 5a and 5b showed activity
against four cancer cell lines at micromolar concentration.
Among all the compounds, 4g, 4h, 6d, and 6g showed
promising activity, while the compounds 4c, 4d, 4f, 6c,
and 6h showed moderate activity. Compound 4h was
considered as the more potent towards all the cancer cell
lines. The structure–activity relationship studies revealed
that the thieno-2-yl group containing molecules showed
more activity. In amide derivatives (4a–h), tagged
aromatic amide derivatives are more potent compared
with simple tagged aliphatic amide derivatives.
Thienopyridine derivatives also showed promising
activity, compared with furopyridine derivatives.
Thienopyridine amide derivatives having thieno-2-yl
group at 6th position and with tagged aromatic (benzyl)
group showed promising cytotoxicity compared with
phenyl group at 6th position of furopyridine ring. In
conclusion, thieo-2-yl group and tagged aromatic
(benzyl) groups are crucial for thienopyridine for
promoting cytotoxic activity.
is, biological activities with chemical structures, and
also used to predict the biological activity of
nonsynthesized compounds; they are structurally related
to training sets [23]. The present investigation reports
the first application of 3D-QSAR to study of alkyl
amide tagged furo/thieno pyridine derivatives as potent
anticancer inhibitors. We studied 16 compounds for
HeLa and COLO205 cell line inhibitors as anticancer
agents using CoMFA (comparative molecular field
analysis) [24] and CoMSIA (comparative molecular
similarity indices analysis) [25]. Models obtained from
3D-QSAR studies provide a strong basis for future
rational design of more active and selective HeLa and
COLO205 cell line inhibitors.
MATERIALS AND METHODS
Data set.
In the present study, alkyl amide tagged
furo/thieno pyridine derivatives as HeLa and COLO205
cell line inhibitors were selected for 3D-QSAR, and their
biological data are presented in Table 1. The IC50 values
of alkyl amide tagged furo/thieno pyridine derivatives
were often converted to their negative logarithm (pIC50)
values. The pIC50 values of these compounds range from
4.20 to 5.07 for HeLa cell lines and 4.28 to 5.11 for
COLO205 cell lines, providing a wide range and
homogenous data set for 3D-QSAR study. The data set
was validated by external test set by taking 5 and 3
compounds that were selected randomly for HeLa and
COLO205 targets, respectively. Remaining compounds
were taken as the training set.
QSAR INTRODUCTION
In general, the 3D-QSAR techniques are valuable
methods of ligand-based drug design by correlating
physicochemical properties from
a set of related
compounds to their known molecular property or
molecular activity values. Validation of QSAR models
plays the vital role in defining the applicability of the
QSAR model for the prediction of designed molecules.
QSAR model is mostly used to correlate properties, that
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S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
Table 2
In vitro cytotoxicity of compounds 4a–h, 5a–d, and 6a–h.
IC50 values (in μM)
Compound
HeLa
COLO205
HepG2
MCF7
4a
4b
4c
4d
4e
4f
4g
4h
5a
5b
5c
5d
6a
6b
6c
6d
6e
6f
21.2 0.18
25.2 0.22
17.5 0.12
17.2 0.23
21.1 0.21
24.2 0.12
10.2 0.12
8.5 0.23
—
32.5 0.33
31.3 0.43
24.6 0.21
16.1 0.12
31.5 0.34
30.6 0.29
11.7 0.28
7.7 0.14
—
12.2 0.51
43.2 0.11
21.4 0.36
29.2 0.38
119.2 0.41
32.6 0.51
14.1 0.20
11.5 0.31
—
—
45.2 0.35
35.5 0.25
31.5 0.22
—
43.3 0.32
12.8 0.22
16.8
—
—
—
41.7 0.52
62.7 0.38
127.3 0.32
31.5 0.42
14.1 0.18
—
48.5 0.22
21.2 0.48
38.4 0.42
0
—
—
—
—
—
63.2 0.52
45.3 0.22
50.2 0.42
—
38.5 0.18
19.2 0.24
—
44.6 0.18
14.2 0.14
24.5 0.11
38.9 0.31
42.5 0.36
—
18.9 0.18
25.7 0.24
—
52.5 0.21
15.8 0.44
32.6 0.25
50.8 0.33
49.8 0.23
—
44.8 0.42
12.8 0.43
—
66.2 0.41
18.4 0.24
44.1 0.21
6g
6h
5-Fluorouracil (standard control)
1.8 0.09
1.9 0.11
1.7 0.08
1.8 0.07
“—” indicates IC50 value >127.3 μg/mL. Cell lines used are as follows: HeLa—cervical cancer (CCL-2), COLO205—colon cancer (CCL-222), HepG2—
liver cancer (HB-8065), and MCF7—breast cancer (HTB-22).
Structure building and minimization. All structures of
alkyl amide tagged furo/thieno pyridine derivatives were
sketched in SYBYL 6.7, a molecular modeling package,
and energy minimization was performed to each and
every alkyl amide tagged furo/thieno pyridine derivative
using Tripos force field with distance-dependent dielectric
function and Powell conjugate gradient algorithm with a
convergence criterion of 0.005 kcal/mol; all the
molecules were minimized by adding Gasteiger–Huckel
charges [26].
Molecular alignment. In general, a geometric similarity
should exist between the modeled structures and that of the
bioactive conformation for 3D QSAR [27]. The spatial
alignment of compounds under study is thus one of the
most sensitive and determining factors in obtaining a
reliable model. Molecular alignment plays a crucial role
in CoMFA and CoMSIA studies [28]. The results of
CoMFA and CoMSIA are extremely sensitive to a
number of factors like alignment rules, orientation of the
compounds that are aligned, probe atom type, and lattice
shifting step size [29]. The accuracy of CoMFA and
CoMSIA model prediction and contour analysis depends
on structural alignment of molecules, and thus, we
applied alignment to align all the molecules used in the
current study. The molecular alignment was performed
by using the SYBYL database align option. This option
uses alignment of structures through pair-wise atom
superpositioning that places all structures in the database
in the same frame of reference as the template compound.
The most common part C-(4-trifluoromethyl-pyridin-3-
yl)-methylamine of the most active compound 4h was
used for HeLa and COLO205 cell lines that were used as
templates, and the remaining molecules were aligned to it
through using the basic. The aligned molecules are
shown in Figure 1.
3D-QSAR studies. For better comprehension of steric,
electrostatic, hydrophobic, hydrogen-bond donor, and
hydrogen-bond acceptor field contributions for the set of
molecules, and to build predictive three-dimensional
quantitative structure–activity relationship models, both
CoMFA and CoMSIA studies were performed on the
Figure 1. Alignment of all the compounds for HeLa cell line inhibitors
and COLO205 cell line inhibitors. [Color figure can be viewed at
wileyonlinelibrary.com]
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Novel alkyl amide functionalized furo/thieno pyridine derivatives
basis of molecular alignment as described earlier. CoMFA
calculates steric and electrostatic properties, whereas
CoMSIA calculates hydrophobic, donor, and acceptor
properties along with steric and electrostatic properties.
CoMFA and CoMSIA properties are calculated with
respect to Lennard–Jones and Columbic potentials.
anticancer inhibitors. The statistical results of CoMFA
and CoMSIA analyses are summarized in Table 3. The
best predictions were obtained with CoMFA standard
model involving cross-validated coefficient (q2) = 0.791
for HeLa and 0.772 for COLO205 and correlation
coefficient (r2) = 0.996 and 0.989 for HeLa and
COLO205,
respectively.
Standard
error
of
CoMFA studies.
Steric and electrostatic properties
estimate = 0.046 for HeLa and 0.035 for COLO205.
Cross-validation = 0.796 and 0.770 for HeLa and
COLO205, respectively, with number of components as 5
and column filtering as 2.0 kcal/mol. In CoMSIA, the
standard model predictions obtained are q2 = 0.779 for
HeLa and 0.722 for COLO205, r2 = 0.991 for HeLa and
0.984 for COLO205, standard error of estimate = 0.061
and 0.045 for HeLa and COLO205, respectively, and
cross-validation = 0.793 and 0.733 for HeLa and
COLO205, respectively, with number of components as 6
and column filtering as 1.0 kcal/mol. Both the targets
show better predictive ability for these compounds.
Bootstrapping method is used to evaluate the robustness
and the statistical confidence of the QSAR model. It
involves simulating a large number of data sets that are
of the same size as original and are produced by
randomly selecting samples from the original set.
Biological activities and predicted and residual values of
both training set and test set CoMFA and CoMSIA are
shown in Table 3.
were calculated using Tripos force field engine, and the
aligned molecules were placed in a 3D grid box so that
the entire set was included. CoMFA descriptors were
generated using sp3 probe atom carrying +1 charge to
generate steric and electrostatic fields; 30-kcal/mol cut-off
was used for the analysis, and standard options were used
for the calculation of regression analysis. Partial least
square was performed by selecting leave-one-out using 5
as the number of components, and the column filtering
was set as 2.0 kcal/mol.
CoMSIA studies.
CoMSIA analysis was performed
with the QSAR option in SYBYL. Five different
properties were used in CoMSIA studies, which are
steric, electrostatic, hydrophobic, donor, and acceptor,
based on which similarity indices between a probe atom
and compound were calculated. The probe atom with 1-Å
radius, +1 charge, and +1 for hydrophobicity was set at
the intersections of the lattice.
Table 3 shows the results of relative contributions for
CoMFA and CoMSIA methods. For CoMFA, steric
contributions are 51.5% and 69.5% for HeLa and
COLO205, respectively, and 48.5% and 30.5% field
contribution was observed for electrostatic respectively
for HeLa and COLO205 cell lines, whereas for CoMSIA,
RESULTS AND DISCUSSION
CoMFA and CoMSIA. CoMFA and CoMSIA methods
were applied to derive 3D-QSAR models for alkyl amide
tagged furo/thieno pyridine derivatives as potential
Table 3
The statistical results of CoMFA and CoMSIA analysis.
HeLa
COLO205
CoMFA
CoMSIA
CoMFA
CoMSIA
q2
0.791
0.996
0.046
95.713
0.796
5
0.799
0.991
0.061
43.676
0.793
6
0.772
0.989
0.035
82.062
0.770
5
0.722
0.984
0.045
37.099
0.733
6
r2
SEE
F‐value
CV
N
Bootstrap
Mean
0.016
0.997
SD
0.013
0.001
Mean
0.011
0.999
SD
0.010
0.001
Mean
0.025
0.993
SD
0.021
0.006
Mean
0.015
0.998
SD
0.020
0.003
SEE
r2
Field contribution (%)
Steric
51.5
48.5
—
—
—
18.5
21.4
30.0
11.1
19.1
69.5
30.5
—
—
—
22.1
18.6
34.3
8.70
16.3
Electrostatic
Hydrophobic
Donor
Acceptor
CV, cross‐validation; SEE, standard error of estimate.
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S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
the observed contributions for steric, electrostatic,
hydrophobic, donor, and acceptor properties are given in
Table 2. Electrostatic property is the main contributor in
CoMSIA analysis.
alkyl amide tagged furo/thieno pyridine derivatives
against anticancer on comparison with CoMFA results
(Tables 4–7).
Contour analysis. CoMFA and CoMSIA steric contour
Tables 4–7 indicate experimental and cross-validated/
predicted biological affinities and residuals obtained by
the CoMFA and CoMSIA for alkyl amide tagged
furo/thieno pyridine derivatives as HeLa and COLO205
cell line inhibitors. For HeLa cell line, CoMFA results
show a higher predictive ability for alkyl amide tagged
furo/thieno pyridine derivatives against anticancer on
comparison with CoMSIA results. For COLO205 cell
line, CoMSIA results show a higher predictive ability for
plots.
For HeLa, the CoMFA model was used to
generate the three-dimensional contour maps to represent
the quantitative structure activity result. A single large
green isopleth is present above amide tagged benzyl ring;
it indicates that the position contains more steric
hindrance. The compound shows four yellow contours at
thieno pyridine ring and three contours at thiophene ring,
which indicates that steric hindrance is less. In CoMSIA, a
very large green contour present amide tagged benzyl ring,
Table 4
Test set: Experimental and cross-validated/predicted biological affinities and residuals obtained by the CoMFA and CoMSIA for alkyl amide tagged furo/
thieno pyridine derivatives as HeLa cell line inhibitors.
CoMFA
CoMSIA
Compound
pIC50
Predicted
Residual
Predicted
Residual
4b
4e
4f
6d
6g
4.60
4.67
4.62
4.72
4.85
4.80
5.03
4.86
4.04
4.51
ꢀ0.20
ꢀ0.36
ꢀ0.24
0.68
4.77
5.04
4.87
4.37
4.45
ꢀ0.17
ꢀ0.37
ꢀ0.25
0.35
0.34
0.40
Table 5
Training set: Experimental and cross-validated/predicted biological affinities and residuals obtained by the CoMFA and CoMSIA for alkyl amide tagged
furo/thieno pyridine derivatives as HeLa cell line inhibitors.
CoMFA
CoMSIA
Compound
pIC50
Predicted
Residual
Predicted
Residual
4a
4c
4d
4g
4h
6a
6c
6f
4.67
4.76
4.76
4.99
5.07
4.30
4.41
4.35
4.61
4.63
4.72
4.57
4.72
4.73
4.25
4.48
4.53
4.47
0.04
0.04
0.19
0.27
0.34
4.61
4.75
4.72
4.88
4.85
4.19
4.52
4.52
4.49
0.06
0.01
0.04
0.11
0.22
0.05
0.11
ꢀ0.07
ꢀ0.18
0.14
ꢀ0.11
ꢀ0.17
0.12
6h
Table 6
Test set: Experimental and cross-validated/predicted biological affinities and residuals obtained by the CoMFA and CoMSIA for alkyl amide tagged furo/
thieno pyridine derivatives as COLO205 cell line inhibitors.
CoMFA
CoMSIA
Compound
pIC50
Predicted
Residual
Predicted
Residual
4f
5d
6d
4.51
4.41
4.59
4.81
4.91
4.57
ꢀ0.30
ꢀ0.50
0.02
4.84
4.78
4.58
ꢀ0.33
ꢀ0.37
0.01
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Month 2019
Novel alkyl amide functionalized furo/thieno pyridine derivatives
Table 7
Training set: Experimental and cross-validated/predicted biological affinities and residuals obtained by the CoMFA and CoMSIA for alkyl amide tagged
furo/thieno pyridine derivatives as COLO205 cell line inhibitors.
CoMFA
CoMSIA
Compound
pIC50
Predicted
Residual
Predicted
Residual
4a
4b
4c
4d
4e
4g
4h
6a
6c
6f
4.49
4.5
4.45
4.63
4.68
4.69
4.63
4.72
4.79
4.51
4.59
4.24
4.67
4.58
0.04
ꢀ0.13
ꢀ0.07
0.10
4.36
4.65
4.74
4.66
4.63
4.78
4.86
4.48
4.61
4.21
4.65
4.58
0.13
ꢀ0.15
ꢀ0.13
0.13
4.61
4.79
4.50
4.93
5.11
4.37
4.72
4.28
4.8
ꢀ0.13
ꢀ0.13
0.21
0.15
0.32
0.25
ꢀ0.14
ꢀ0.11
0.13
0.11
0.04
0.13
ꢀ0.09
0.07
0.15
ꢀ0.09
6g
6h
4.49
which increases the steric hindrance, and a large yellow
contour below the amide ring. Adding bulk groups at this
ring decreases the biological activity.
tagged benzyl ring, where activity increases, and two
large yellow contours are present above amide tagged
benzyl ring, covering thiophene ring, which decreases the
activity by adding bulk groups. The most active
compound shows that yellow and green contours are
present, which are shown in Figure 2.
In CoMFA, the most active compound showed two
green contours, a large and green contour. A large
polyhedron is present above amide tagged benzyl ring
and a small polyhedron below the thiophene ring,
indicating steric favorable region where biological
activity increases by adding bulky groups. One big and
one small yellow contours are present, covering
thiophene ring where bulky groups decrease the activity
of the compound. In CoMSIA, the most active compound
shows that a large green contour is present above amide
CoMFA electrostatics contours plots.
For HeLa, the
electrostatic contours maps of CoMFA and CoMSIA are
shown in blue and red colors. In both CoMFA and
CoMSIA, medium-sized blue contours are present near
amide tagged benzyl ring, indicating that addition of
positive charge groups may increase the biological
activity of a compound. The blue contours are in
Figure 2. CoMFA and CoMSIA contour maps of the most active compound. Sterically favored areas are shown in green color (contribution level of
80%). Sterically unfavored areas are shown in yellow color (contribution level of 20%). [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
favorable region and red contours in disfavorable region. A
very small-sized red contour and a medium-sized red
contour are present above amide tagged benzyl ring; at
this position, electron density is estimated to increase the
biological activity. Adding electro-negative groups may
enhance the activity. For COLO205, a small blue-colored
contour is present near amide tagged benzyl ring, and
medium-sized red-colored contours are present above
amide tagged benzyl ring, shown in Figure 3. In
CoMSIA, blue contour is present above thiophene ring,
where addition of negative groups enhances the biological
activity.
hydrophobic substitution, shown in Figure 4. For both
HeLa and COLO205, a large white contour is present
around thiophene, indicating disfavored conformation for
hydrophobic substitution.
COMSIA hydrogen-bond donor contour analysis.
The
graphical representation of the field contributions of the
hydrogen-bond donor is shown in Figure 5. Donor
contour maps are shown in cyan and purple colors. Cyan
contour maps explain the position of hydrogen-bond
donor groups, which increases biological activity, while
purple contours are biologically unflavored, shown in
Figure 5. For HeLa, a large cyan-colored contour is
present around amide tagged benzyl ring, and in
COLO205, the most active compound shows a small cyan
isopleth above amide tagged benzyl ring, which enhance
the biological activity, and two medium-sized purple
isopleths are present around amide tagged benzyl ring,
which reduce the biological activity.
COMSIA hydrophobic contour analysis.
CoMSIA
hydrophobic contour maps are shown in yellow and
white colors. For HeLa, two medium-sized yellow
contours present amide tagged benzyl ring. For
COLO205, a large yellow contour is present by covering
the amide tagged benzyl ring; this indicates favorable
Figure 3. CoMFA and CoMSIA electrostatic contour maps of the most active compound. Positive potential favored areas are shown in blue color (con-
tribution level of 80%). Positive potential unfavored areas are shown in red color (contribution level of 20%). [Color figure can be viewed at
wileyonlinelibrary.com]
Figure 4. Hydrophobic contour maps are shown in yellow and white areas, indicating where hydrophobic amino acid residues will increase or decrease
the affinity, respectively. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Novel alkyl amide functionalized furo/thieno pyridine derivatives
Figure 5. Hydrogen-bond donor contours are shown in cyan and purple areas, indicating where hydrogen-bond donor groups on the ligand will increase
or decrease the affinity, respectively. [Color figure can be viewed at wileyonlinelibrary.com]
COMSIA hydrogen-bond acceptor contour analysis.
Hydrogen-bond acceptor contours are represented in
magenta and red colors. Magenta color indicates favorable
region, and red color indicates unfavorable region of
biological activity. In HeLa, the most active compound
shows two large magenta isopleths, one magenta
polyhedron covering amide tagged benzyl ring and one
above amide tagged benzyl ring, whereas in COLO205,
the most active compound shows that a medium-sized
magenta and a large red contour and a small red contour
are present, which are shown in Figure 6.
134.9, 137.3, 139.9, 142.2, 160.9; MS (ESI): m/z
[(M + H)+]: 336. HRMS m/z Calcd for C16H12F3N3O2
[(M + H)+]: 336.0369. Found: 336.0371.
3-Amino-N-methyl-6-phenyl-4-(trifluoromethyl)thieno[2,3-b]
pyridine-2-carboxamide (4b).
Yellow solid; mp 171–
173°C; IR (KBr, cmꢀ1): 1662 (–CONH–); 1H NMR
(DMSO-d6, 300 MHz): δ ppm 2.74 (s, 3H, –N–CH3),
6.53 (br s, 2H, –NH2), 7.38 (br s, 1H, –CONH–),
7.43–7.52 (m, 3H, Ar–H), 7.79 (s, 1H, Py–H), 7.90–
7.95 (m, 2H, Ar–H); 13C NMR (DMSO-d6, 75 MHz):
δ ppm 25.2, 123.1, 123.7, 125.3, 126.0, 128.0, 129.0,
129.8, 129.9, 131.3, 133.4, 133.8, 134.6, 162.3;
MS (ESI): m/z [(M + H)+]: 352. HRMS m/z Calcd
for C16H12F3N3OS [(M + H)+]: 352.0116. Found:
352.0118.
General
procedure.
Ethyl 3-amino-6-(phenyl/
thiophen-2-yl)-4-(trifluoromethyl) furo/thieno[2,3-b]
pyridine-2-carboxylate 3 (0.01 mol) reacted with different
primary aliphatic amines (0.015 mol) at 80–90°C for 10–
12 h; after completion of the reaction, reaction mixture
was poured into crushed ice, and solid was formed. This
solid was filtered and dried to afford the solid product 4.
3-Amino-N-methyl-6-phenyl-4-(trifluoromethyl)furo[2,3-b]
pyridine-2-carboxamide (4a). Pale yellow solid; mp 185–
3-Amino-N-methyl-6-(thiophen-2-yl)-4-(trifluoromethyl)
furo[2,3-b]pyridine-2-carboxamide (4c). Yellow solid; mp
161–162°C; IR (KBr, cmꢀ1): 1664 (–CONH–); 1H
NMR (DMSO-d6, 300 MHz): δ ppm 2.73 (s, 3H, –N–
CH3), 6.51 (br s, 2H, –NH2), 7.32 (br s, 1H,
–CONH–), 7.51 (dd, J = 4.15, 1H, Ar–H), 7.75
(dd, J = 4.91, 1H, Ar–H), 7.98 (s, 1H, Py–H), 8.14
(dd, J = 3.77, 1H, Ar–H); 13C NMR (DMSO-d6,
75 MHz): δ ppm 26.2, 122.0, 125.4, 125.8, 127.0,
128.1, 130.0, 132.0, 134.7, 137.4, 139.9, 142.1, 143.6,
160.5; MS (ESI): m/z [(M + H)+]: 342. HRMS m/z
187°C; IR (KBr, cmꢀ1): 1660 (–CONH–); 1H NMR
(DMSO-d6, 300 MHz): δ ppm 2.68 (s, 3H, –N–CH3),
6.52 (br s, 2H, –NH2), 7.32 (br s, 1H, –CONH–), 7.48–
7.56 (m, 3H, Ar–H), 7.78 (s, 1H, Py–H), 8.10–8.17 (m,
2H, Ar–H); 13C NMR (DMSO-d6, 75 MHz): δ ppm 25.4,
119.3,125.2, 125.5, 127.1, 128.1, 129.0, 130.6, 133.6,
Figure 6. Magenta and red areas indicate where hydrogen-bond acceptor groups on the ligand will increase or decrease the affinity, respectively Alkyl
amide tagged furo/thieno pyridine derivatives as HeLa cell line inhibitor. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
Calcd for C14H10F3N3O2S [(M + H)+]: 342.0553. Found:
NMR (DMSO-d6, 300 MHz): δ ppm 4.32 (d, 2H,
J = 5.83, –CH2–N–), 6.51 (br s, 2H, –NH2), 7.32 (br s,
1H, –CONH–), 7.41 (dd, J = 4.71, 1H, Ar–H), 7.48–7.58
(m, 3H, Ar–H), 7.62–7.68 (m, 2H, Ar–H), 7.86 (dd,
J = 4.74, 1H, Ar–H), 7.96 (dd, J = 3.75, 1H, Ar–H), 8.09
(s, 1H, Py–H); 13C NMR (DMSO-d6, 75 MHz): δ ppm
46.0, 119.7, 120.6, 122.0, 123.9, 125.4, 126.0, 127.7,
128.9, 129.8, 130.7, 132.2, 133.8, 135.9, 136.3, 142.1,
144.7, 159.5; MS (ESI): m/z [(M + H)+]: 434. HRMS m/z
Calcd for C20H14F3N3OS2 [(M + H)+]: 434.1025. Found:
434.1027.
342.0551.
3-Amino-N-methyl-6-(thiophen-2-yl)-4-(trifluoromethyl)
thieno[2,3-b]pyridine-2-carboxamide (4d).
Yellow solid;
mp 184–186°C; IR (KBr, cmꢀ1): 1662 (–CONH–); H
NMR (DMSO-d6, 300 MHz): δ ppm 2.72 (s, 3H, –N–
CH3), 6.52 (br s, 2H, –NH2), 7.33 (br s, 1H, –CONH–),
7.52 (dd, J = 4.72, 1H, Ar–H), 7.65 (dd, J = 4.73, 1H,
Ar–H), 7.81 (s, 1H, Py–H), 8.84 (dd, J = 3.72, 1H, Ar–
H); 13C NMR (DMSO-d6, 75 MHz): δ ppm 25.4, 121.9,
123.5, 124.6, 125.7, 127.7, 128.3, 129.0, 130.2, 135.9,
137.9, 162.3; MS (ESI): m/z [(M + H)+]: 358. HRMS m/z
Calcd for C14H10F3N3OS2 [(M + H)+]: 358.1012. Found:
1
General
procedure.
Ethyl 3-amino-6-(phenyl/
thiophen-2-yl)-4-(trifluoromethyl)furo/thieno[2,3-b]
358.1015.
pyridine-2-carboxylate 3 (0.01 mol) reacted with excess
of secondary amines (0.015 mol) and potassium
carbonate (0.81 mol) were charged into a round bottom
flask, and the mixture was heated at 100°C for 12 h.
The reaction mixture was cooled to room temperature,
treated with crushed ice, and neutralized with 1-N HCl.
The solid precipitate was filtered and washed with
excess water, and the crude product was recrystallized
3-Amino-N-benzyl-6-phenyl-4-(trifluoromethyl)furo[2,3-b]
pyridine-2-carboxamide (4e). Pale yellow solid; mp 192–
193°C; IR (KBr, cmꢀ1): 1667 (–CONH–); 1H NMR
(DMSO-d6, 300 MHz): δ ppm 4.35 (d, 2H, J = 5.86,
–CH2–N–), 6.53 (br s, 2H, –NH2), 7.32 (br s, 1H,
–CONH–), 7.41–7.58 (m, 6H, Ar–H), 7.79 (s, 1H,
Py–H), 8.10–8.18 (m, 4H, Ar–H); 13C NMR (DMSO-d6,
75 MHz): δ ppm 46.0, 119.0, 120.1, 122.3, 122.6, 123.9,
124.8, 125.8, 127.9, 128.9, 130.8, 133.9, 134.3, 135.5,
137.4, 144.5, 145.1, 160.1; MS (ESI): m/z [(M + H)+]:
412. HRMS m/z Calcd for C22H16F3N3O2 [(M + H)+]:
from ethanol.
(3-Amino-6-phenyl-4-(trifluoromethyl)furo[2,3-b]pyridin-2-
yl)(4-methylpiperazin-1-yl)methanone (5a).
Yellow solid;
mp 145–147°C; IR (KBr, cmꢀ1): 1668 (–CONH–); H
NMR (DMSO-d6, 300 MHz): δ ppm 2.32 (s, 3H, –CH3),
2.84–2.96 (m, 4H, –(CH2)2–), 3.12–3.25 (m, 4H,
–(CH2)2–), 6.58 (br s, 2H, –NH2), 7.38–7.48 (m, 3H,
Ar–H), 7.67–7.74 (m, 2H, Ar–H), 8.12 (s, 1H, Py–H);
13C NMR (DMSO-d6, 75 MHz): δ ppm 46.3, 49.8, 50.7,
123.7, 125.2, 126.0, 128.0, 129.0, 129.8, 131.3, 133.4,
133.8, 134.6, 142.1, 162.3; MS (ESI): m/z [(M + H)+]:
434. HRMS m/z Calcd for C20H19F3N4O2 [(M + H)+]:
1
412.0229. Found: 412.0231.
3-Amino-N-benzyl-6-phenyl-4-(trifluoromethyl)thieno[2,3-b]
pyridine-2-carboxamide (4f). Dark yellow solid; mp 197–
199°C; IR (KBr, cmꢀ1): 1666 (–CONH–); 1H NMR
(DMSO-d6, 300 MHz): δ ppm 4.34 (d, 2H, J = 5.83,
–CH2–N–), 6.51 (br s, 2H, –NH2), 7.35 (br s, 1H,
–CONH–), 7.44–7.60 (m, 6H, Ar–H), 7.81 (s, 1H,
Py–H), 8.12–8.19 (m, 4H, Ar–H); 13C NMR (DMSO-d6,
75 MHz): δ ppm 46.1, 119.9, 120.8, 123.0, 123.4, 124.6,
125.6, 126.4, 127.9, 129.6, 131.4, 133.9, 134.2, 135.6,
137.3, 141.8, 147.9, 160.1; MS (ESI): m/z [(M + H)+]:
428. HRMS m/z Calcd for C22H16F3N3OS [(M + H)+]:
405. 0126. Found: 405.0128.
(3-Amino-6-phenyl-4-(trifluoromethyl)thieno[2,3-b]pyridin-
2-yl)(4-methylpiperazin-1-yl)methanone (5b). Yellow solid;
1
mp 162–164°C; IR (KBr, cmꢀ1): 1665 (–CONH–); H
NMR (DMSO-d6, 300 MHz): δ ppm 2.34 (s, 3H, –CH3),
2.79–2.87 (m, 4H, –(CH2)2–), 3.12–3.23 (m, 4H,
–(CH2)2–), 6.52 (br s, 2H, –NH2), 7.36–7.48 (m, 3H,
Ar–H), 7.58–7.65 (m, 2H, Ar–H), 8.04 (s, 1H, Py–H);
13C NMR (DMSO-d6, 75 MHz): δ ppm 46.0, 49.1, 50.9,
122.8, 123.3, 124.4, 125.4, 126.5, 127.1, 128.0, 129.0,
130.6, 132.2, 136.1, 146.6, 160.8; MS (ESI): m/z
[(M + H)+]: 421. HRMS m/z Calcd for C20H19F3N4OS
428.0105. Found: 428.0108.
3-Amino-N-benzyl-6-(thiophen-2-yl)-4-(trifluoromethyl)
furo[2,3-b]pyridine-2-carboxamide (4g). Yellow solid; mp
151–152°C; IR (KBr, cmꢀ1): 1661 (–CONH–); H NMR
1
(DMSO-d6, 300 MHz): δ ppm 4.34 (d, 2H, J = 5.85,
–CH2–N–), 6.52 (br s, 2H, –NH2), 7.32 (br s, 1H,
–CONH–), 7.43 (dd, J = 4.72, 1H, Ar–H), 7.49–7.57 (m,
3H, Ar–H), 7.64–7.71 (m, 2H, Ar–H), 7.78 (dd, J = 4.72,
1H, Ar–H), 7.82 (dd, J = 3.72, 1H, Ar–H), 8.24 (s, 1H,
Py–H); 13C NMR (DMSO-d6, 75 MHz): δ ppm 46.2,
118.0, 119.0, 121.1, 121.6, 122.7, 123.7, 124.5, 126.0,
127.7, 129.5, 132.0, 132.4, 133.7, 137.9, 139.9, 147.0,
160.3; MS (ESI): m/z [(M + H)+]: 418. HRMS m/z Calcd
for C20H14F3N3O2S [(M + H)+]: 418.0342. Found:
[(M + H)+]: 421. 0432. Found: 421.0434.
(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)furo[2,3-b]
pyridin-2-yl)(4-methylpiperazin-1-yl)methanone
(5c).
Yellow solid; mp 152–154°C; IR (KBr, cmꢀ1): 1662
1
(–CONH–); H NMR (DMSO-d6, 300 MHz): δ ppm 2.61
(s, 3H, –CH3), 2.73–2.81 (m, 4H, –(CH2)2–), 3.75–3.82
(m, 4H, –(CH2)2–), 6.52 (br s, 2H, –NH2), 7.43 (dd,
J = 4.76, 1H, Ar–H), 7.58 (dd, J = 4.72, 1H, Ar–H), 7.83
(s, 1H, Py–H), 8.82 (dd, J = 3.72, 1H, Ar–H); 13C NMR
(DMSO-d6, 75 MHz): δ ppm 46.2, 49.6, 50.9, 120.1,
418.0343.
3-Amino-N-benzyl-6-(thiophen-2-yl)-4-(trifluoromethyl)
thieno[2,3-b]pyridine-2-carboxamide (4h).
Yellow solid;
mp 165–166°C; IR (KBr, cmꢀ1): 1665 (–CONH–); H
1
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Novel alkyl amide functionalized furo/thieno pyridine derivatives
123.6, 125.5, 126.7, 128.1, 129.0, 130.7, 133.3, 134.3,
135.1, 139.7, 141.9, 159.8; MS (ESI): m/z [(M + H)+]:
411. HRMS m/z Calcd for C18H17F3N4O2S [(M + H)+]:
411.0251. Found: 411.0254.
(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)thieno[2,3-b]
(d, 3H, –CH3), 4.32–4.41 (m, 1H, –CH–), 6.51 (br s, 2H,
–NH2), 7.48 (dd, J = 4.71, 1H, Ar–H), 7.78 (dd,
J = 4.78, 1H, Ar–H), 7.98 (s, 1H, Py–H), 8.09 (dd,
J = 3.72, 1H, Ar–H), 8.45 (d, 1H, –CONH–); 13C NMR
(DMSO-d6, 75 MHz): δ ppm 16.6, 48.9, 121.4, 122.6,
123.5, 125.0, 126.8, 127.1, 129.4, 130.8, 134.9, 136.5,
142.3, 146.4, 160.2, 171.3; MS (ESI): m/z [(M + H)+]:
400. HRMS m/z Calcd for C16H12F3N3O4S [(M + H)+]:
pyridin-2-yl)(4-methylpiperazin-1-yl)methanone
(5d).
Yellow solid; mp 163–164°C; IR (KBr, cmꢀ1): 1662
1
(–CONH–); H NMR (DMSO-d6, 300 MHz): δ ppm 2.35
(s, 3H, –CH3), 2.70–2.82 (m, 4H, –(CH2)2–), 3.12–3.21
(m, 4H, –(CH2)2–), 6.51 (br s, 2H, –NH2), 7.46 (dd,
J = 4.72, 1H, Ar–H), 7.54 (dd, J = 4.76, 1H, Ar–H), 7.81
(s, 1H, Py–H), 8.82 (dd, J = 3.72, 1H, Ar–H); 13C NMR
(DMSO-d6, 75 MHz): δ ppm 46.2, 49.2, 50.9, 122.0,
125.4, 125.8, 127.0, 128.1, 130.0, 132.0, 134.7, 137.3,
139.9, 142.1, 143.6, 160.5; MS (ESI): m/z [(M + H)+]:
427. HRMS m/z Calcd for C18H17F3N4OS2 [(M + H)+]:
427.0502. Found: 427.0505.
General procedure. To the mixture of ethyl 3-amino-
6-(phenyl/thiophen-2-yl)-4-(trifluoromethyl)furo/thieno
[2,3-b]pyridine-2-carboxylate 3 (0.01 mol), L-amino acid
(0.02 mol), potassium carbonate (0.05 mol), and dimethyl
sulfoxide (10 ml) was added and refluxed for 12 h. The
reaction mixture was cooled and diluted with ice water.
The aqueous solution was neutralized with 1-N HCl until
the pH is neutral. The precipitated solid was filtered,
400.0118. Found: 400.0120.
2-(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)thieno[2,3-
b]pyridine-2-carboxamido)propanoic acid (6d).
Yellow
solid; mp 183–185°C; IR (KBr, cmꢀ1): 1660 (–CONH–),
1
1728 (COOH); H NMR (DMSO-d6, 300 MHz): δ ppm
1.38 (d, 3H, –CH3), 4.26–4.38 (m, 1H, –CH–), 6.52 (br
s, 2H, –NH2), 7.56 (dd, J = 4.74, 1H, Ar–H), 7.79 (dd,
J = 4.78, 1H, Ar–H), 8.01 (s, 1H, Py–H), 8.15 (dd,
J = 3.71, 1H, Ar–H), 8.48 (d, 1H, –CONH–); 13C NMR
(DMSO-d6, 75 MHz): δ ppm 16.8, 47.9, 121.4, 123.7,
124.9, 125.1, 126.4, 128.0, 129.0, 129.9, 131.3, 134.8,
142.2, 146.8, 161.5, 171.3; MS (ESI): m/z [(M + H)+]:
416. HRMS m/z Calcd for C16H12F3N3O3S2 [(M + H)+]:
416.1058. Found: 416.1056.
2-(3-Amino-6-phenyl-4-(trifluoromethyl)furo[2,3-b]pyridine-
2-carboxamido)-3-phenylpropanoic acid (6e).
Pale yellow
solid; mp 199–201°C; IR (KBr, cmꢀ1): 1665 (–CONH–),
1
1725 (COOH); H NMR (DMSO-d6, 300 MHz): δ ppm
dried, and recrystallized from ethanol.
2-(3-Amino-6-phenyl-4-(trifluoromethyl)furo[2,3-b]pyridine-
2.69 (d, 2H, –CH2–Ph), 4.61–4.72 (m, 1H, –CH–), 6.51
(br s, 2H, –NH2), 7.51–7.58 (m, 4H, Ar–H), 7.72–7.85
(m, 6H, Ar–H), 8.15 (s, 1H, Py–H), 8.42 (d, 1H,
–CONH–); 13C NMR (DMSO-d6, 75 MHz): δ ppm 34.7,
58.0, 1206, 122.1, 122.8, 124.0, 124.4, 125.6, 125.9,
126.5, 127.2, 128.1, 129.1, 131.5, 132.4, 134.7, 142.0,
146.7, 158.8, 170.6; MS (ESI): m/z [(M + H)+]: 470.
HRMS m/z Calcd for C24H18F3N3O4 [(M + H)+]:
2-carboxamido)propanoic acid (6a).
Yellow solid; mp
153–155°C; IR (KBr, cmꢀ1): 1659 (–CONH–), 1728
1
(COOH); H NMR (DMSO-d6, 300 MHz): δ ppm 1.43
(d, 3H, –CH3), 4.42–4.51 (m, 1H, –CH–), 6.52 (br s,
2H, –NH2), 7.44–7.58 (m, 3H, Ar–H), 7.83 (s, 1H, Py–
H), 8.01–8.11 (m, 2H, Ar–H), 8.42 (br s, 1H,
–CONH–); 13C NMR (DMSO-d6, 75 MHz): δ ppm
16.3, 48.9, 119.5, 120.5, 121.2, 121.8, 123.1, 123.7,
124.6, 125.2, 126.0, 134.6, 142.1, 146.6, 162.8,
170.1; MS (ESI): m/z [(M + H)+]: 394. HRMS m/z
Calcd for C18H14F3N3O4 [(M + H)+]: 394.0546. Found:
470.0189. Found: 470.0191.
2-(3-Amino-6-phenyl-4-(trifluoromethyl)thieno[2,3-b]
pyridine-2-carboxamido)-3-phenylpropanoic acid (6f).
Pale yellow solid; mp 182–184°C; IR (KBr, cmꢀ1):
1
1660 (–CONH–), 1731 (COOH); H NMR (DMSO-d6,
394.0549.
300 MHz): δ ppm 2.71 (d, 2H, –CH2–Ph), 4.42–4.51
(m, 1H, –CH–), 6.52 (br s, 2H, –NH2), 7.42–7.56
(m, 4H, Ar–H), 7.72–7.87 (m, 6H, Ar–H), 8.03 (s, 1H,
Py–H), 8.41 (d, 1H, –CONH–); 13C NMR (DMSO-d6,
75 MHz): δ ppm 34.7, 58.0, 121.0, 122.7, 123.4,
124.6, 125.0, 125.9, 126.7, 127.8, 128.6, 129.0, 129.4,
131.3, 132.4, 134.7, 143.0, 147.3, 159.9, 171.3; MS
2-(3-Amino-6-phenyl-4-(trifluoromethyl)thieno[2,3-b]
pyridine-2-carboxamido)propanoic acid (6b).
Pale yellow
solid; mp 185–187°C; IR (KBr, cmꢀ1): 1656 (–CONH–),
1
1731 (COOH); H NMR (DMSO-d6, 300 MHz): δ ppm
1.37 (d, 3H, –CH3), 4.41–4.52 (m, 1H, –CH–), 6.49 (br
s, 2H, –NH2), 7.46–7.57 (m, 3H, Ar–H), 7.78 (s, 1H, Py–
H), 8.04–8.14 (m, 2H, Ar–H), 8.43 (d, 1H, –CONH–);
13C NMR (DMSO-d6, 75 MHz): δ ppm 16.6, 48.9,
121.4, 122.6, 123.5, 125.0, 126.8, 127.1, 129.4, 130.8,
134.9, 136.5, 142.3, 146.4, 160.2, 170.5; MS (ESI): m/z
[(M + H)+]: 410. HRMS m/z Calcd for C18H14F3N3O3S
(ESI): m/z [(M
+
H)+]: 486. HRMS m/z Calcd
for C24H18F3N3O3S [(M + H)+]: 486.0287. Found:
486.0287.
2-(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)furo[2,3-b]
pyridine-2-carboxamido)-3-phenylpropanoic acid (6g).
[(M + H)+]: 410.0112. Found: 410.0112.
Yellow solid; mp 196–198°C; IR (KBr, cmꢀ1): 1662
(–CONH–), 1734 (COOH); 1H NMR (DMSO-d6,
300 MHz): δ ppm 2.72 (d, 2H, –CH2–Ph), 4.42–4.51 (m,
1H, –CH–), 6.50 (br s, 2H, –NH2), 7.42 (dd, J = 4.74,
2-(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)furo[2,3-b]
pyridine-2-carboxamido)propanoic acid (6c). Yellow solid;
mp 169–171°C; IR (KBr, cmꢀ1): 1658 (–CONH–), 1726
1
(COOH); H NMR (DMSO-d6, 300 MHz): δ ppm 1.33
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

S. Bhoomandla, S. K. Gunda, S. Kotoori, and P. R. Kanuparthy
Vol 000
[2] Baraldi, P. G.; Cacciari, B.; Romagnoli, R.; Spalluto, G.;
Monopoli, A.; Ongini, E.; Varani, K.; Borea, P. A. J Med Chem 2002,
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1H, Ar–H), 7.48–7.53 (m, 3H, Ar–H), 7.65–7.68 (m, 2H,
Ar–H), 7.73 (dd, J = 3.72, 1H, Ar–H), 7.81 (dd, J = 4.74,
1H, Ar–H), 8.11 (s, 1H, Py–H), 8.43 (d, 1H, –CONH–);
13C NMR (DMSO-d6, 75 MHz): δ ppm 34.0, 57.2,
120.3, 121.8, 122.5, 123.7, 124.0, 125.0, 125.9, 126.8,
127.7, 128.0, 128.8, 131.3, 132.5, 134.7, 143.0, 147.7,
160.0, 170.9; MS (ESI): m/z [(M + H)+]: 476. HRMS m/z
Calcd for C22H16F3N3O4S [(M + H)+]: 476.0615. Found:
[3] Goodacre, S. C.; Street, L. J.; Hallett, D. J.; Crawforth, J. M.;
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Kazmierski, W. M.; Chong, P. Y.; De Anda, F.; Edelstein, M.; Ferris, R.;
Peckham, J.; Wheelan, P.; Xiong, Z.; Zhang, H.; Nishizawa, R.; Takaoka,
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Nashashibi, I.; Xu, Y.; Dugar, S.; Levy, D. E.; Jung, J. Bioorg Med Chem
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476.0618.
2-(3-Amino-6-(thiophen-2-yl)-4-(trifluoromethyl)thieno[2,3-
b]pyridine-2-carboxamido)-3-phenylpropanoic acid (6h).
Yellow solid; mp 181–183°C; IR (KBr, cmꢀ1): 1665
(–CONH–), 1737 (COOH); 1H NMR (DMSO-d6,
300 MHz): δ ppm 2.64 (d, 2H, –CH2–Ph), 4.42–4.52 (m,
1H, –CH–), 6.54 (br s, 2H, –NH2), 7.44 (dd, J = 4.72,
1H, Ar–H), 7.48–7.52 (m, 3H, Ar–H), 7.58–7.64 (m, 2H,
Ar–H), 7.78 (dd, J = 4.74, 1H, Ar–H), 7.84 (dd, J = 3.71,
1H, Ar–H), 8.23 (s, 1H, Py–H), 8.42 (d, 1H, –CONH–);
13C NMR (DMSO-d6, 75 MHz): δ ppm 34.4, 58.2,
120.6, 122.1, 122.7, 123.8, 124.3, 125.2, 125.8, 126.9,
128.4, 129.0, 129.3, 132.0, 133.0, 134.7, 143.0, 147.6,
159.4, 171.5; MS (ESI): m/z [(M + H)+]: 492. HRMS m/z
Calcd for C22H16F3N3O3S2 [(M + H)+]: 492.0118.
Found: 492.0115.
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CONCLUSION
In conclusion,
a series of novel alkyl amide
functionalized trifluoromethyl substituted furo/thieno
pyridine derivatives 4a–h, 5a–d, and 6a–h were prepared
and evaluated for anticancer against four human cancer
cell lines. Among all the compounds screened, the
compounds 4g and 4h showed significant activity against
all cell lines at micromolar concentration (8.5–16.8 μM).
3D-QSAR, CoMFA, and CoMSIA studies have been
applied to alkyl amide functionalized trifluoromethyl
substituted furo/thieno pyridine derivatives. Both these
CoMFA and CoMSIA models for HeLa and COLO205
inhibitors generated have confirmed to be statistically
precise with higher q2 and r2. The information achieved
from CoMFA and CoMSIA models could lead to a better
design of novel selective and higher potent alkyl amide
functionalized trifluoromethyl substituted furo/thieno
pyridine derivatives as anticancer agents.
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Acknowledgments. Author Srinu Bhoomandla is thankful to the
Director, Gitam University, Hyderabad, for providing lab facility
and Malla Reddy Institute of Technology and Science,
Secunderabad, for constant encouragement.
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Journal of Heterocyclic Chemistry
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SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of the
article.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet