Efficient L-Proline catalyzed synthesis of some new (4-substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-diones bearing thiazolopyrimidine derivatives and evaluation of their pharmacological activities

Article abstract of DOI:10.1016/j.molstruc.2021.131324

In the present study, a simple and efficient protocol has been developed to synthesize a series of new (4-substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-dione derivatives (4a-g) through L-proline-catalyzed reactio

Full text of DOI:10.1016/j.molstruc.2021.131324

Journal of Molecular Structure 1247 (2022) 131324
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstr
Efficient L-Proline catalyzed synthesis of some new
(4-substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-
d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-diones bearing
thiazolopyrimidine derivatives and evaluation of their pharmacological
activities
S.H. Sukanyaa, Talavara Venkatesha,∗, S.J. Aditya Raob,∗, Muthipeedika Nibin Joyc
a Department of PG Studies and Research in Chemistry, Jnanasahyadri, Kuvempu University, Shankaraghatta, Karnataka 577451, India
b Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute, Mysore, Karnataka 570020, India
c Innovation Center for Chemical and Pharmaceutical Technologies, Institute of Chemical Technology, Ural Federal University, 19 Mira Street, Yekaterinburg
620002, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
In the present study,
a simple and efficient protocol has been developed to synthesize a se-
Received 21 June 2021
Revised 13 August 2021
Accepted 15 August 2021
Available online 17 August 2021
ries of new (4-substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-
dione derivatives (4a-g) through L-proline-catalyzed reaction of 2-amino-4-(4-substituted-phenyl)thiazole
(1), substituted benzaldehyde (2), and barbituric/thiobarbituric acid (3) at a refluxed temperature in aque-
ous ethanol under mild and metal-free conditions. The obtained compounds were evaluated for in vitro
cytotoxicity and anti-inflammatory effects. The in silico docking studies provided the probable interactions
of synthesized compounds with P38 MAP kinase and MMP-9 proteins. The structures of all the synthe-
sized compounds were confirmed using analytical and spectroscopic techniques. The in vitro cytotoxic-
ity studies revealed the potential cytotoxic effects of the compounds 4f and 4g. The anti-inflammatory
studies suggested the prominent anti-inflammatory effects of the compounds 4a and 4g. The SAR stud-
ies showed the importance of electron-withdrawing groups in enhancing the potency among the tested
compounds. The results of in silico studies supported our findings from in vitro analysis in terms of drug-
likeness of the synthesized compounds and their effective interactions with P38 MAP kinase and MMP-9
proteins envisaging their use as prominent therapeutic agents.
Keywords:
Thaizole-pyrimidine derivatives
Cytotoxicity
Anti-inflammatory
SAR
ADME-toxicology study
Molecular docking
© 2021 Elsevier B.V. All rights reserved.
1. Introduction
catalysis [4]. It is efficient in catalyzing various organic transfor-
mations [5], Knoevenagel-type condensation [6], Biginelli reaction
Multicomponent one-step reactions (MCRs) are upstanding as a
valuable tool for synthesizing polyfunctional molecules with high
competence over multistep synthesis. Globally, it has been ex-
plored as an efficient tool for preparing several active drugs [1].
MCRs offer many advantages as they avoid unnecessary expensive
purification, high atom economy, toxic reagents, and solvents con-
sumption [2].
[7], Mannich [8], Michael [9], Diels-Alder [10], α-amination reac-
tion [11] and asymmetric Hantzsch reaction [12].
Heterocyclic compounds, mainly polyfunctionalized heterocy-
cles (PFHs), are widespread in bioactive natural compounds and
marketed pharmaceuticals, food and paints, agrochemicals, dyes
and pigments, electrochemicals, optoelectronic, fluorescence sen-
sors, and many other application-oriented resources [13–15].
Therefore, investigations on the synthesis of PFHs have received
particular attention. Among the privileged class of various het-
erocyclic compounds, thiazole and pyrimidine are key moieties
in medicinal chemistry. The significant pharmacological poten-
tial of these molecules includes antimicrobial, antioxidant, anti-
tubercular, anti-inflammatory, antiviral, and anticancer properties
[16,17].
Proline is a bifunctional chiral homogenous organocatalyst that
is cost-effective, efficient, and readily available than any other cat-
alyst [3]. L-Proline has both acidic (−COOH) and basic (−NH) func-
tionality and catalyzes chemical transformations similar to enzyme
∗
Corresponding author.
E-mail
addresses:
venkateshatalwar@gmail.com
(T.
Venkatesh),
adityaraosj@gmail.com (S.J. Aditya Rao).
https://doi.org/10.1016/j.molstruc.2021.131324
0022-2860/© 2021 Elsevier B.V. All rights reserved.

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Cancer is a global malignant disease causing severe health prob-
lems and even death. Cancer is generally characterized by the rapid
and uncontrolled proliferation of cells, thereby leading to the inva-
siveness of various tissues. The advancements in the medical field
have given good insights into the inheritance of cancer. However,
seeking a proper cure for cancer is still a major unsolved chal-
lenge to the scientific community [18]. A defensive response of
the body that minimizes tissue damage by inducing physiologi-
cal adaptations can be termed as inflammation. There are different
inflammatory disorders such as retinitis, multiple sclerosis, pso-
riasis, atherosclerosis, inflammatory bowel diseases, osteoarthritis,
and rheumatoid arthritis [19]. Although the significant effects of
inflammation do not look critical prima facie, chronic inflamma-
tion is a vital contributory factor in mortality and morbidity. These
observations emphasize the importance of developing potent an-
ticancer and anti-inflammatory agents with minimum side effects.
In this aspect, the concept of synthesizing novel heterocyclic com-
pounds is rational as a majority of available anticancer and anti-
inflammatory agents contain one or more heterocyclic groups. The
significance of pyrimidine and thiazole-based compounds are un-
derlined by their presence in various drugs available in the market
(Fig. 1).
derivatives and evaluation of their pharmacological potentials as
anticancer and anti-inflammatory molecules. The study extends to
predict the binding interactions of synthesized molecules target-
ing p38 MAP kinase and MMP-9 proteins along with their in silico
pharmacokinetic and pharmacodynamics profiling.
2. Experimental
2.1. Materials and method
The general information regarding the various solvents,
reagents, and instruments used for analysis has been explained in
the supporting information section.
2.2. Synthesis of 2-amino-4-(4-substituted-phenyl) thiazoles (1a-b)
The 2-amino-4-(4-substituted-phenyl)thiazole derivatives (1a-b)
were synthesized by the reaction of 4-methoxy/nitro substituted
phenacyl bromide (1 mmol) with thiourea (1 mmol). 15 mL aque-
ous ethanol was refluxed with constant stirring for about 2–3 h
according to the procedure of Ramamurthy et al., [22] then re-
crystallized using methanol and dried to afford pure solid products
(Scheme 1). The reported m.p. of compounds 1a and 1b are 208 °C
and 238 °C, respectively.
Since pyrimidine and thiazole are important scaffolds in drug
discovery, combining these pharmacophores into a single entity
could enhance their pharmacological properties. Rationalizing this
hypothesis by synthesizing a series of thiazolopyrimidine deriva-
tives could result in novel molecules displaying considerable phar-
macological potentials. Earlier, our research group has reported
different derivatives of pyrimidine moieties and other biologically
important heterocyclic compounds [20,21]. We herein report our
initial results of the synthesis of some novel thiazolopyrimidine
2.2.1. 4-(4-methoxyphenyl)-1,3-thiazol-2-amine (1a)
White solid, yield-70%, m.p. 206–208 °C; 1H NMR (400 MHz,
DMSO-d6, δ ppm): 3.78 (s, 3H, OCH3), 7.21 (s, 2H, NH2), 7.40 (s,
1H, CH), 8.11–8.13 (d, J = 8 Hz, 2H, Ar-H), 8.20–8.22 (d, J = 8 Hz,
2H, Ar-H); 13C NMR (100 MHz, DMSO–d6, δ ppm): 56.18 (OCH3),
–
107.12, 125.10, 127.51, 142.01, 147.12, 148.26 and 169.03 (C NH2);
HRMS: m/z 206.0120 [M+H]+.
2.2.2. 4-(4-nitrophenyl)-1,3-thiazol-2-amine (1b)
Yellow solid, yield-72%, m.p. 236–238 °C; 1H NMR (400 MHz,
DMSO_d6, δ ppm): 7.22 (s, 2H, NH2), 7.39 (s, 1H, CH), 8.01–8.03
(d, J = 8 Hz, 2H, Ar-H), 8.20–8.22 (d, J = 8 Hz, 2H, Ar-H); 13C
NMR (100 MHz, DMSO_d6, δ ppm): 107.03, 124.44, 126.71, 141.31,
–
–
146.36, 148.26 (C NO2) and 169.03 (C NH2); HRMS: m/z 222.0760
[M+H]+.
2.3. General procedure for the synthesis of (4-substituted-phenyl)-1,5-
dihydro-2H-pyrimido[4,5-d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-
dione derivatives (4a-g)
An equimolar quantity of 2-amino-4-(4-substituted-phenyl)
thiazoles (1a/b, 1 mmol), substituted benzaldehyde (2, 1 mmol),
and barbituric/thiobarbituric acid (3, 1 mmol) in the presence of
aqueous ethanol using 10 mol% of L-Proline was refluxed with con-
stant stirring for about 4–5 h. Simultaneously, the reaction was
monitored by TLC (Ethyl acetate & petroleum ether). After com-
pletion of the reaction, the reaction mixture was cooled to room
temperature and poured into the 100 mL flake ice with vigorous
stirring to get solid precipitate. Then, it was filtered, washed, re-
crystallized from absolute ethanol, and dried to afford pure solid
products (4a-g).
Scheme 1. Synthesis of 2-amino-4-(4-substituted-phenyl)thiazoles derivatives
Fig. 1. Some of the drugs containing thiazolopyrimidine moieties available in the
(1a-b).
market.
2

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
11.34 (s, 1H, NH); 13C NMR (100 MHz, DMSO-d6, δ ppm): 56.78,
59.45 (OCH3), 94.23, 118.12, 121.21, 128.32, 129.08, 130.21, 132.08,
133.34, 133.89, 134.08, 135.16, 136.12, 149.01, 150.03, 154.23,
155.12, 158.68, 160.43 and 162.32 (C=O); LCMS: m/z 436 [M+2];
Anal.Calcd for C22H18 N4O5S: C 60.82, H 4.18, N 12. 90%, Found: C
60.79, H 4.13, N 12.88%.
2.3.1. 7-(4-Methoxyphenyl)-5-(3-nitrophenyl)-1,5-dihydro-2H-
pyrimido[4,5-d][1,3] thiazolo[3,2-a]pyrimidine-2,4(3H)-dione (4a)
Yellow solid, yield-82%, m.p. 290–292 °C; FTIR (KBr, υ cm−1):
3363 (NH), 2920 (OCH3), 1668 (C=O) & 1602 (C=N); 1H NMR
(400 MHz, DMSO-d6, δ ppm): 3.74 (s, 3H, OCH3), 5.63 (s, 1H, CH),
6.96–6.98 (d, J = 8 Hz, 2H, Ar-H), 7.36–7.55 (m, 5H, Ar-H), 7.87 (s,
1H, CH), 7.97–7.99 (d, J = 8 Hz, 1H, Ar-H), 9.01 (s, 1H, NH) and 9.99
(s, 1H, NH); 13C NMR (100 MHz, DMSO-d6, δ ppm): 60.14, 91.60,
118.17, 118.86, 125.32, 126.24, 127.48, 127.74, 133.11, 134.12, 134.88,
135.21, 135.35, 138.76, 152.43, 152.60, 155.71, 157.25, 164.41 and
169.35 (C=O); LCMS: m/z 447 [M-2]; Anal.Calcd for C21H15N5O5S:
C 56.12, H 3.36, N 15.58%, Found: C 56.05, H 3.12, N 15.47%.
2.3.6. 5-(4-Hydroxyphenyl)-7-(4-nitrophenyl)-2-thioxo-1,2,3,5-
tetrahydro-4H-pyrimido [4,5-d][1,3]thiazolo[3,2-a]pyrimidin-4-one
(4f)
Yellow solid, yield-81%, m.p. 280–284 °C; FTIR (KBr, υ cm−1):
3471 (OH), 3294 (NH), 1666 (C=O)
&
1591 (C=N); 1H NMR
(400 MHz, DMSO-d6, δ ppm): 5.46 (s, 1H, CH), 6.52–6.54 (d,
J = 8 Hz, 2H, Ar-H), 6.80–6.82 (d, J = 8 Hz, 1H, Ar-H), 7.87(s, 1H,
Ar-H), 7.82–7.84 (d, J = 8 Hz, 2H, Ar-H), 8.18–8.22 (t, 2H, Ar-H), 8.72
(s, 1H, Ar-H), 11.50 (s, 1H, OH), 12.230 (s, 1H, NH), 12.327 (s, 1H,
NH); 13C NMR (100 MHz, DMSO-d6, δ ppm): 96.72, 107.30, 115.21,
116.37, 124.59, 126.91, 127.86, 128.31, 128.86, 130.91, 132.74, 146.69,
147.92, 155.08, 155.84, 162.57, 163.77, 169.57 (C=O) and 173.06
(C=S); HRMS: m/z 452.3012 [M+H]+; Anal.Calcd for C20H13N5O4S2:
C 53.21, H 2.90, N 15.51%, Found: C 53.17, H 2.87, N 15.47%.
2.3.2. 5-(4-Hydroxyphenyl)-7-(4-methoxyphenyl)-1,5-dihydro-2H-
pyrimido[4,5-d][1,3] thiazolo[3,2-a]pyrimidine-2,4(3H)-dione (4b)
Yellow solid, yield-80%, m.p. 295–298 °C; FTIR (KBr, υ cm−1):
3473 (OH), 3221 (NH), 2922 (OCH3), 1666 (C=O) & 1602 (C=N);
1H NMR (400 MHz, DMSO–d6, δ ppm): 3.78 (s, 3H, OCH3), 5.36
(s, 1H, CH), 6.66–6.68 (d, J = 8 Hz, 2H, Ar-H), 6.86 (s, 1H, Ar-H),
6.99–7.23 (m, 3H, Ar-H), 7.29–7.31 (t, J = 8 Hz, 1H, Ar-H), 7.83–7.85
(d, J = 8 Hz, 1H, Ar-H), 8.27 (s, 1H, Ar-H), 11.16 (s, 1H, NH), 11.28
(s, 1H, NH) and 12.00 (s, 1H, OH); 13C NMR (100 MHz, DMSO-
d6, δ ppm): 60.11 (OCH3), 93.11, 118.80, 121.40, 129.42, 130.70,
131.48, 132.96, 133.07, 133.97, 134.28, 135.14, 149.60, 152.06,
154.18, 154.60, 158.79, 160.47 and 163.61 (C=O); LCMS: m/z 422
[M+2]; Anal.Calcd for C21H16 N4O4S: C 59.99, H 3.84, N 13.33%,
Found: C 59.93, H 3.82, N 13.28%.
2.3.7. 5-(4-Chloro-3-nitrophenyl)-7-(4-nitrophenyl)-2-thioxo-1,2,3,5-
tetrahydro-4H-pyrimido [4,5-d][1,3]thiazolo[3,2-a]pyrimidin-4-one
(4g)
Yellow solid, yield-79%, m.p. 304–308 °C; FTIR (KBr, υ cm−1):
3284 (NH), 1666 (C=O) & 1618 (C=N); 1H NMR (400 MHz, DMSO-
d6, δ ppm): 5.57 (s, 1H, CH), 7.32–7.35 (d, J = 8 Hz, 2H, Ar-
H), 7.51–7.53 (d, J = 8 Hz, 1H, Ar-H), 7.65 (s, 1H, Ar-H), 7.85–
7.87 (d, J = 8 Hz, 1H, Ar-H), 7.98–8.00 (d, J = 8 Hz, 1H, Ar-H),
8.18–8.26 (m, 2H, Ar-H), 10.89 (s, 2H, NH); 13C NMR (100 MHz,
DMSO-d6, δ ppm): 90.57, 107.18, 122.37, 123.86, 124.20, 124.55,
125.32, 126.82, 131.09, 131.37, 132.60, 141.08, 144.98, 146.48,
147.86, 148.02, 162.64, 169.19, 169.75 (C=O) and 174.38 (C=S);
HRMS: m/z 513.1334 [M-1] and 511.1325 [M-2]; Anal.Calcd for
C20H11 ClN6O5S2: C 46.65, H 2.15, N 16.32%, Found: C 46.60, H 2.11,
N 16.28%.
2.3.3. 5-(4-Hydroxy-3-methoxyphenyl)-7-(4-methoxyphenyl)-1,5-
dihydro-2H-pyrimido [4,5-d][1,3]thiazolo[3,2-a]pyrimidine-
2,4(3H)-dione (4c)
Yellow solid, yield-81%, m.p. 267–270 °C; FTIR (KBr, υ cm−1):
3452 (OH), 3273 (NH), 2955 (OCH3), 1678 (C=O) & 1597 (C=N);
1H NMR (400 MHz, DMSO-d6, δ ppm): 3.84 (s, 6H, OCH3), 5.83
(s, 1H, CH), 6.99–7.05 (m, 4H, Ar-H), 7.18–7.20 (d, J = 8 Hz, 2H,
Ar-H), 7.89–7.91 (d, J = 8 Hz, 2H, Ar-H), 11.47 (s, 1H, NH), 11.74
(s, 1H, NH) and 12.13 (s, 1H, OH); 13C NMR (100 MHz, DMSO-
d6, δ ppm): 55.96, 56.03 (OCH3), 80.69, 96.59, 110.66, 114.28,
114.49, 122.54, 125.35, 126.99, 127.64, 128.12, 129.20, 129.79,
130.55, 131.37, 131.94, 135.26, 143.27, 143.58, 163.34 and 163.70
(C=O); HRMS: m/z 451.3702 [M+H]+; Anal.Calcd for C22H18 N4O5S:
C 58.66, H 4.03, N 12.44%, Found: C 58.63, H 3.98, N 12.38%.
2.4. Pharmacological activities
2.4.1. Cytotoxicity
In vitro cytotoxicity was assessed by MTT assay by following the
procedure of Kumbar et al. [23] against MCF-7 (Breast cancer) cell
line. The cells were seeded in a 96-well flat-bottom microplate and
maintained at 37 °C in 95% humidity and 5% CO2 overnight. Differ-
ent concentrations (200, 100, 50, 25, 12.5 and 6.25 μg/mL) of sam-
ples were treated. The cells were incubated for another 48 h, and
the wells were washed twice with PBS. 20 μL of MTT staining solu-
tion was added to each well, and the plate was incubated at 37 °C.
After 4 h, 100 μL of DMSO was added to each well to dissolve the
formazan crystals, and absorbance was recorded at 570 nm using
a microplate reader. The percentage of cell survival was calculated
by using the following formula [24,25].
2.3.4. 5-(4-N-dimethylphenyl)-7-(4-methoxyphenyl)-1,5-dihydro-2H-
pyrimido[4,5-d][1,3] thiazolo[3,2-a]pyrimidine-2,4(3H)-dione (4d)
Orange red solid, yield-79%, m.p. 275–278 °C; FTIR (KBr, υ
cm−1): 3322 (NH), 2832 (CH3), 1673 (C=O) & 1614 (C=N); 1H NMR
(400 MHz, DMSO-d6, δ ppm): 2.43 (s, 6H, CH3), 3.78 (s, 3H, OCH3),
5.43 (s, 1H, CH), 6.66–6.68 (d, J = 8 Hz, 2H, Ar-H), 6.89 (s, 1H, Ar-
H), 7.03–7.29 (m, 3H, Ar-H), 7.32–7.34 (t, J = 8 Hz, 1H, Ar-H), 7.83–
7.85 (d, J = 8 Hz, 1H, Ar-H), 8.26 (s, 1H, Ar-H), 11.20 (s, 1H, NH) and
11.32 (s, 1H, NH); 13C NMR (100 MHz, DMSO-d6, δ ppm): 22.01
(CH3), 56.18 (OCH3), 96.24, 117.20, 122.18, 128.40, 129.63, 130.01,
130.60, 131.28, 132.35, 133.08, 133.68, 134.19, 135.94, 149.24,
151.98, 154.03, 155.62, 158.87, 160.47 and 163.61 (C=O); LCMS: m/z
449 [M+2]; Anal.Calcd for C23H21N5O3S: C 61.78, H 4.73, N 15.65%,
Found: C 61.71, H 4.68, N 15.58%.
Mean OD of test compound
% of cell survival =
x100
Mean OD of Negative control
2.4.2. Anti-inflammatory activity
2.3.5. 5,7-Bis(4-methoxyphenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]
thiazolo[3,2a] pyrimidine -2,4(3H)-dione (4e)
The anti-inflammatory activity of the synthesized compounds
was investigated by the Gelatin Zymography electrophoresis
method [26]. 50 μL of matrix metalloproteinase (MMP) sample
was mixed with 50 μL of the synthesized compounds and incu-
bated for 1 hour at room temperature. MMP sample with Tetra-
cycline hydrochloride served as positive control while MMP sam-
ple alone served as a negative control. After incubation, an equal
quantity of non-reducing buffer was added to the above samples,
Light yellow solid, yield-81%, m.p. 285–290 °C; FTIR (KBr, υ
cm−1): 3228 (NH), 2962 (OCH3), 1666 (C=O) & 1612 (C=N); 1H
NMR (400 MHz, DMSO-d6, δ ppm): 3.84 (s, 6H, OCH3), 5.39 (s, 1H,
CH), 6.68–6.70 (d, J = 8 Hz, 2H, Ar-H), 6.88 (s, 1H, Ar-H), 7.00–
7.28 (m, 3H, Ar-H), 7.31–7.33 (t, J = 8 Hz, 1H, Ar-H), 7.83–7.85
(d, J = 8 Hz, 1H, Ar-H), 8.28 (s, 1H, Ar-H), 11.23 (s, 1H, NH) and
3

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Scheme 2. Synthesis of (4-substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3] thiazolo[3,2a]-pyrimidine-2,4(3H)-dione derivatives (4a-g).
Scheme 3. Plausible mechanism of synthesized compounds (4a-g).
mixed well, and 30 μL of each sample was loaded into the gel. The
electrophoresis was run at 50 V for 15 min and later increased to
100 V until the bromophenol blue reaches the bottom of the plate.
After electrophoresis, the gel was washed with SDS (sodium do-
decyl sulfate) surfactant followed by zymogram renaturing buffer
for 1 hour to remove the remaining surfactant from the gel and al-
lowed the gel for renaturing of the proteins. The gel was further in-
cubated in zymogram incubation buffer overnight at 37 0C. Finally,
the gel was stained with Coomassie blue R-250, and the develop-
ment of white bands indicated the presence of gelatinases with the
lower bands representing gelatinases-A (MMP-2) which are about
72 kD, while the upper bands are gelatinases-B (MMP-9) which are
about 95 kD [27].
Fig. 2. Images of anticancer study of the synthesized compounds (4a-g) and Nega-
tive control (NC).
Table 1
Effect of catalyst on synthesized compound 4a.
Entry
Catalyst
Solvent
Temperature (°C)
Time (hours)
Yield (%)
1
2
3
4
5
6
7
8
9
L-Proline
HCl
EtOH: H2O
EtOH
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
RT
6
90
8
90[43]
84[44]
89[45]
78[46]
77[47]
87[48]
95[49]
82[50]
TBAHS
–
EtOH: H2O
EtOH: acetic acid
MeOH
3
8
Zn(ClO4)2.6H2O
TMGT
8
Ionic liquid
EtOH/H2O
Solvent-free
Ball milling
5
InCl3
1
p-TSA
4
ZnO NPs
40min
4

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
2.4.3. In silico oral bioavailability assessment and ADME-toxicology
studies
ties used in the RO5 filter are derived using Osiris Data
warrior V.4.4.3 software [31]. Different parameters describing
the pharmacodynamics and pharmacokinetic properties were
assessed using the admetSAR server [32]. The bioavailabil-
ity scores were predicted using the molinspiration server
[33].
The oral bioavailability of the synthetic molecules (4a-
g) was predicted using the Lipinski rule-of-five (RO5) fil-
ter [28] to derive the candidate drug’s pharmacokinetic (PK)
and pharmacodynamics (PD) [29,30]. The structural proper-
Table 2
Physical and analytical data of synthesized compounds (4a-g).
Compd
4a
R
R1
H
R2
X
O
Aldehyde
Product
Yield (%)
82
MP ( °C)
OCH3
NO2
290–292
4b
4c
4d
OCH3
OCH3
OCH3
OH
H
O
O
O
80
81
79
295–298
267–270
275–278
OH
OCH3
N(CH3)2
H
4e
OCH3
OCH3
H
O
81
285–290
(continued on next page)
5

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Table 2 (continued)
Compd
4f
R
R1
R2
H
X
S
Aldehyde
Product
Yield (%)
81
MP ( °C)
NO2
OH
280–284
4g
NO2
Cl
NO2
S
79
304–308
Table 3
Percentage of cell viability against MCF-7 cell line of the synthesized compounds (4a-g).
Concentration
Mean cell Viability of MCF-7
in
4a
4b
4c
4d
4e
4f
4g
Std
μg/mL
NC
100
6.25
96.57 0.66
93.15 1.21
92.37 1.54
73.21 1.44
45.79 1.55
23.21 0.99
93.68 1.20
99.22 1.10
90.03 1.21
76.79 2.09
70.56 0.55
47.82 0.66
27.88 1.44
93.60 2.37
90.65 1.22
89.72 0.88
82.24 0.66
80.84 0.77
53.89 1.87
31.62 1.10
115.00 1.27
76.95 0.88
64.17 1.87
29.44 1.10
26.79 1.65
23.83 0.55
19.00 0.44
18.90 0.69
93.77 0.55
73.05 2.21
62.46 1.32
49.53 1.10
40.81 1.54
29.60 1.32
57.63 1.47
40.72 2.58
23.98 0.64
22.17 0.96
20.48 0.47
19.68 0.64
19.00 0.64
1.15 0.49
64.03 0.96
44.00 1.44
40.84 1.44
38.35 0.80
36.99 0.48
34.50 1.12
8.55 2.05
–
12.5
–
25
–
50
–
100
–
200
–
IC50 in μg/mL
298.86 6.35
Std- Paclitaxel (PTX), NC- Negative control.
Values are Mean SE, N = 3, ∗P<0.01 vs. Control.
Table 4
Anti-inflammatory activity results of synthesized compounds (4a-g).
2.4.4. In silico molecular docking studies
Automated docking was used to study the interactions of syn-
thesized compounds at the binding pocket of the target proteins.
The mode of cell death can be studied by considering necrosis,
apoptosis, necroptosis, autophagic cell death, etc. The inhibition of
P38 MAP kinase is likely to affect cellular proliferation account-
ing for cell toxicity [34,35]. This can be used as a test for mito-
chondrial respiration indirectly connected by cellular toxicity [36].
Similarly, Matrix metalloproteinases (MMPs) play important roles
in the interaction between inflammatory cells [37] and MMP-9,
specifically involved in several cancers associated with inflamma-
tion [38]. Inhibitors of metalloproteinase (TIMP) can be used to
control the elevated expression of MMP-9 to control pathological
conditions such as cancer and inflammation [39]. In the present
study, the molecular interactions of the synthesized compounds
at the binding pocket of P38 MAP kinase [36] and MMP-9 tar-
gets [40] were studied using automated docking by employing the
Autodock Vina program [41]. The co-crystallized structure of P38
MAP kinase (PDB ID: 1OUK) and MMP-9 (PDB ID: 5CUH) were re-
trieved from the protein databank, and their substrate binding sites
were identified using pdbsum server [36,42]. A grid box of dimen-
Anti-inflammatory
activity against MMP-2
(% Inhibition)
Anti-inflammatory
activity against MMP-9
(% Inhibition)
Entry
Compound
1
2
3
4
5
6
7
8
9
4a
4b
4c
90 0.41
50 0.48
37 0.37
33 0.38
45 0.36
78 0.32
85 0.34
99 0.51
–
45 0.38
5
5
5
0.25
0.41
0.42
4d
4e
4f
22 0.47
20 0.61
35 0.54
95 0.35
–
4 g
PC
NC
–
PC-Positive control, NC Negative control.
Values are Mean SE, N = 3, ∗P<0.01 vs. Control.
residues forming the active pocket. The binding interactions were
visualized using Biovia Discovery Studio Visualizer V.20.1.
2.4.5. Statistical analysis
˚
sions 56 × 60 × 48 A with X, Y & Z coordinates at 44.746, 34.234
The experiments were performed in triplicates. Difference be-
tween the group’s mean was measured using one-way analysis of
variance. The results were compared with the control and P-value
<0.01 was considered statistically significant. The statistical calcu-
lations reported in the study were performed using SPSS statistics
˚
and 32.603 for P38 MAPk and 44 × 52 × 48 A with X, Y & Z co-
ordinates at 15.463, 23.591and −1.658 for MMP-9 were created re-
spectively. All the torsions were allowed to rotate for synthesized
compounds during docking [30]. The grid box was set around the
6

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Fig. 3. A graph of % of surviving cells of compounds (4a-g) at different concentration against MCF-7 cell line (a and b) and A graph of IC50 value of compounds (4a-g) against
MCF-7 cell line (c).
Table 5
Bioavailability, drug likeness and in silico pharmacokinetic assessment of synthesized compounds (4a-g).
Bioavailibility and Drug likeness
In silico Pharmacokinetics
Compounds
Total
Polar
Human
CYP450
Molecular
Rotatable
Bonds
Surface
Area
Drug
intestinal
Caco-2 per- Blood brain 2D6
weight
cLogP
H-Acceptors
H-Donors
likeness
absorption
meability
barrier
substrate
4a
4b
4c
4d
4e
4f
449.446
420.448
450.474
447.518
434.475
451.486
514.929
2.1585
2.7934
2.7234
3.0355
3.0691
2.2433
2.2734
10
8
2
3
3
2
2
3
2
4
3
4
4
4
3
4
154.15
128.56
137.79
111.57
117.56
180.17
205.76
−0.37683
4.658
0.863+
0.893+
0.893+
0.918+
0.900+
0.832+
0.846+
0.656-
0.637-
0.601-
0.575-
0.515-
0.723-
0.805-
0.972+
0.969+
0.966+
0.972+
0.971+
0.972+
0.973+
0.853-
0.861-
0.861-
0.842-
0.865-
0.868-
0.872-
9
4.658
8
5.3679
4.6405
−1.1518
−1.1113
8
9
4g
11
Table 6
In silico pharmacodynamics and bioactivity assessment of synthesized compounds (4a-g).
In silico Pharmacodynamics
Bioactivity assessment
Ion
Compounds
Aerobic
biodegrad- Ames
Nuclear
receptor Protease Enzyme
modulator inhibitor ligand inhibitor inhibitor
Reproductive
Mutagenic Tumorigenic Effective
GPCR
channel
Kinase
Irritant
ability
toxicity
Hepatotoxicity ligand
4a
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
HIGH
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
HIGH
HIGH
NONE
NONE
NONE
NONE
NONE
NONE
NONE
0.95-
0.703+
0.593-
0.588-
0.567-
0.587-
0.700+
0.712-
0.875+
0.900+
0.850+
0.850+
0.850+
0.825+
0.850+
−0.50
−0.35
−0.35
−0.37
−0.38
−0.53
−0.55
−0.73
−0.67
−0.66
0.69
−0.68
−0.56
−0.55
−0.54
−0.58
−0.85
−0.83
−0.58
−0.42
−0.45
−0.49
−0.51
−0.75
−0.90
−0.91
−0.81
−0.081
−0.81
−0.81
−0.83
−0.87
−0.15
0.0
4b
4c
0.995-
1.00-
−0.01
−0.06
−0.05
−0.25
−0.33
4d
4e
0.991-
0.995-
0.995-
1.00-
−0.69
−0.69
−0.69
4f
4g g
7

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Enol II attacks the carbonyl group of the activated benzaldehyde
III and affords Knoevenagel intermediate IV. It undergoes Michael
addition with 2-amino-4-(4-substituted-phenyl) thiazole V, affords
intermediates VI & VII, followed by cyclocondensation giving the
final product VIII.
Firstly, we studied the effect of catalyst on the reaction. In
the previous reports, this method was carried out in the presence
of different catalysts such as HCl, TBAHS, Zn(ClO4)2.6H2O, TMGT,
InCl3, p-TSA, ZnO NPs, and also in the absence of catalyst (Table 1).
We screened different conditions to find the influence of catalyst in
the progress of reaction as well as in the increase of product yield.
The results were not very encouraging. Therefore, we concluded
that the best result was obtained in the presence of L-Proline at
10 mol%, whereas a further increase in the quantity of catalyst
does not have any significant effect on the reaction kinetics.
The structures of new (4-substituted-phenyl)-1,5-dihydro-
2H-pyrimido[4,5-d][1,3]thiazolo[3,2a]-pyrimidine-2,4(3H)-dione
derivatives (4a-g) were confirmed by recording their IR, 1H NMR,
13C NMR, and Mass spectral data. IR spectrum of compound
4a showed the absorption band in the region 3363 cm−1 that
can be attributed to the amide stretching vibration, 2920 cm−1
corresponds to methoxy group (OCH3), and the absorption band
at 1668 cm−1 corresponds to stretching vibration of the carbonyl
group (C=O). Another stretching vibrational band at 1602 cm−1
corresponds to the C=N bond. The 1H NMR spectrum of com-
pound 4a exhibited two singlet peaks at δ 9.99, and 9.01 ppm,
which corresponds to two NH protons of pyrimidine nucleus (s,
2H, NH) and another doublet peak at δ 7.98 (d, J = 8 Hz, 1H,
Ar-H) corresponds to aromatic proton. A singlet peak at δ 7.87
corresponds to the CH proton of the thiazole core (s, 1H, Ar-CH).
A multiplet peak was observed in the range of δ 7.36–7.55 ppm
corresponding to five aromatic protons (m, 5H, Ar-H) and doublet
peak in the range of δ 6.97 was observed due to two aromatic
protons (d, J = 8 Hz, 2H, Ar-H). A singlet peak at δ 5.63 due to CH
proton (s, 1H, CH) and another singlet at δ 3.74 corresponding to
three methoxy protons (s, 3H, OCH3) was also observed in the 1H
NMR spectrum. In addition, the 13C NMR spectrum of compound
4a exhibited a peak at δ 60.14 ppm due to methoxy carbon and
peaks at δ 164.41 and 169.35 ppm, which correspond to carbonyl
carbons.
Fig. 4. Electrophoresis bands for the anti-inflammatory activity of compounds
(4a-g).
The mass spectrum showed molecular ion peak [M-2] at m/z
is 447, which corresponds to the molecular weight of the com-
pound 4a (Supporting information: S1–S24). The physical and an-
alytical data of synthesized compounds (4a-g) has been tabulated
in Table 2.
Fig. 5. Anti-inflammatory activity of compounds (4a-g).
v.20 package and the graphs were plotted using GraphPad Prism
v.7.0.
3.2. Pharmacological activities
3. Results and discussion
3.2.1. Cytotoxicity study
3.1. Chemistry
The in vitro cytotoxicity of the synthesized compounds (4a-g)
was evaluated against MCF-7 (Breast cancer) cell line (Fig. 2). A
graph detailing the concentration versus survival fraction of the
compounds was plotted (Fig. 3), and the results were expressed
as the half-maximal inhibitory concentrations (IC50) (Table 3). Pa-
clitaxel used as a reference standard showed an IC50 value of
298.86 6.35 μg/mL.
In the present study, we developed
a simple, convenient,
and environmentally safe method to synthesize some new (4-
substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo
[3,2a]-pyrimidine-2,4(3H)-dione derivatives (4a-g) via one-
pot three-component reaction of 2-amino-4-(4-substituted-
phenyl)thiazoles (1), substituted benzaldehyde (2) and barbi-
turic/thiobarbituric acid (3) in aqueous ethanol using L-Proline as
a catalyst (Scheme 2).
The cytotoxicity results suggested that the test compounds
have a very good selectivity against the MCF-7 cell line com-
pared to the reference standard. The cytotoxicity data revealed
that compounds 4f & 4g possessed significant IC50 of 1.15 0.49
& 8.55 2.05 μg/mL, respectively. The remaining compounds also
displayed reliable selectivity with an IC50 value in the range of
18.90 0.69 to 115.00 1.27 μg/mL compared to reference standard
Paclitaxel. The compounds 4f & 4g demonstrated highly promising
cell viability at 6.25 μg/mL concentration. The preventive mecha-
nism may include the inhibition of genotoxic effects, increased an-
The plausible mechanism for the formation of new (4-
substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo
[3,2a]-pyrimidine-2,4(3H)-dione derivatives has been proposed in
Scheme 3. The reaction was initiated by the formation of enol II
from barbituric/thiobarbituric acid I. L-Proline was coordinated
through a hydrogen bond to the oxygen atom of the substituted
benzaldehyde III, and then it was activated for nucleophilic attack.
8

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
tioxidant and anti-inflammatory activities, inhibition of proteases
and cell proliferation, protection of intracellular communications
to modulate apoptosis [51], and signal transduction pathways. The
presence of electron-withdrawing nitro and chloro groups is sup-
posed to be the main reason for superior activity profile of the
compounds 4f & 4g.
anti-inflammatory effects displayed by the synthesized molecules
4a & 4g may be due to the presence of electron-withdrawing nitro
groups in those compounds.
3.2.3. Structure activity relationship (SAR) studies
The SAR studies have been carefully carried out for the newly
synthesized compounds (4a-g). The anti-inflammatory activity
studies against MMP-2 and MMP-9 revealed the vital presence
of electron-withdrawing groups for superior potency. The com-
pounds 4a and 4g demonstrated a prominent anti-inflammatory
effect compared to other molecules. The compound 4a possesses
one nitro group, whereas 4g has two nitro groups. The electron-
withdrawing functionalities are known to increase lipophilicity,
which enhances the cell-permeability of the synthesized com-
pounds. This could be the possible reason for the improved activity
profile of these compounds.
3.2.2. Anti-inflammatory activity
Gelatin zymography is the most sensitive and widely used as-
say for detecting the percentage inhibition of compounds against
two enzymes MMP-2 and MMP-9 (Figs.
4 and 5). The anti-
inflammatory activity results revealed that the compounds 4a & 4g
exhibited a noticeable activity in terms of% inhibition when com-
pared to other compounds. Compounds 4a & 4g displayed encour-
aging anti-inflammatory activity against matrix metalloproteinase-
2 (MMP-2) with% inhibition of 90 0.41 & 85 0.34 and moder-
ate anti-inflammatory activity against matrix metalloproteinase-9
(MMP-9) with% inhibition of 45 0.38 & 35 0.54 as compared to
positive control (99 0.51 & 95 0.35%), (Table 4) respectively. In-
flammation is a defense response displayed by the body against
infections and tissue damage [52]. It is a complex event character-
ized by redness (Latin rubor), heat (calor), swelling (tumor), and
pain (dolor). Anti-inflammatory drugs like aspirin, ibuprofen, and
diclofenac are currently in use. The probable reason behind the
All the newly synthesized compounds exhibited remarkable an-
ticancer activity compared to the reference drug, Paclitaxel. Among
the tested compounds, 4f and 4g displayed prominent IC50 values,
compared to other members of the series. Compounds 4f and 4g
demonstrated promising cell viability at 6.25 μg/mL concentration.
The presence of electron-withdrawing nitro and chloro group is
presumed to be the main reason for the superior activity profile of
4f and 4g. However, the combined effect of the electron-donating
Fig. 6. Three-dimensional and two-dimensional representations of molecular interactions between p38 MAPk target protein and synthesized compounds 4a (a, b), 4b (c, d),
4c (e, f), 4d (g, h), 4e (I, j), 4f (k, l), 4g (m, n) and reference drug Paclitaxel (o, p).
9

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
hydroxyl group and the electron-withdrawing nitro group could be
the possible reason for the superior potency of the compound 4f.
considered biologically active, whereas the values between −0.50
to 0.0 are considered to be moderately active and below −0.5 to
be inactive [29,54]. The bioactivity assessment indicated that the
molecules do not belong to the GPCR group of ligands, do not
modulate ion channels, non-kinase inhibitors, non-nuclear recep-
tor ligands, non-protease, and non-enzyme inhibitors (Table 6).
3.2.4. In silico ADME-toxicology studies
Assessment of absorption, distribution, metabolism, excretion
and toxicity (ADME-T) studies has been the crucial step in high
throughput screening [53], and the in silico methods are proven
to be a reliable approach. The bioavailability and drug-likeness of
all the synthesized compounds (4a-g) were assessed based on the
molecular properties. The results indicated that all the compounds
under study pass through Lipinski’s filter without any violation.
In silico pharmacokinetic studies indicated that the synthesized
molecules could penetrate the blood-brain barrier and human in-
testinal barrier but impermeable to Caco-2. (Table 5).
3.2.5. In silico molecular docking studies
The molecular interaction between the synthesized molecules
and appropriate target proteins was studied using the in silico
molecular docking method [55]. The binding interactions were
compared with standard drugs and expressed as kcal/mol. The
interactions of P38 MAPk with compound 4f displayed the least
binding energy of −8.7 kcal/mol followed by 4g (−8.4 kcal/mol)
(Fig. 6). The compounds 4a, 4c, 4b, 4e, and 4d have bound with
the minimum binding energies of −8.3, −8.3, −8.1, −7.9, and
−7.5 kcal/mol with P38 MAPk protein, respectively (Fig. 6). Simi-
larly, the synthesized compound 4g has bound to the target pro-
The In silico pharmacodynamics studies indicated the non-
mutagenic, non-tumorigenic, non-irritant, AMES nontoxic with
high reproductive effects and possible hepatotoxicity effects for all
synthesized molecules. The bioactivity scores higher than 0.0 are
Fig. 7. Three-dimensional and two-dimensional representations of molecular interactions between MMP-9 target protein and synthesized compounds 4a (a, b), 4b (c, d), 4c
(e, f), 4d (g, h), 4e (I, j), 4f (k, l), 4g (m, n) and reference drug Tetracycline (o, p).
10

S.H. Sukanya, T. Venkatesh, S.J. Aditya Rao et al.
Journal of Molecular Structure 1247 (2022) 131324
Table 7
In silico molecular docking results for anticancer and anti-inflammatory activity of synthesized compounds (4a-g) and standard drugs.
Anticancer activity Anti-inflammatory activity
Binding energy
Binding energy
in kcal/mol
Compd.
in kcal/mol
H-bonds
Residues
Compd.
H-bonds
Residues
Paclitaxel
−8.0
−8.3
−8.1
−8.3
−7.5
−7.9
−8.7
−8.4
03
04
04
03
02
02
03
03
TYR35, LYS53, ASP168
TYR35, LYS53, MET109, GLU71
TYR35, LYS53, MET109, ASP168
GLY170, ARG189, ASP168
GLY170, ASP168
Tetracycline
−7.3
−8.6
−7.9
−7.8
−7.9
−8.0
−8.0
−9.3
04
04
03
02
03
03
01
05
TYR251, LEU256, PRO254, PRO255
HIS226, HIS230, HIS236, TYR248
HIS226, HIS230, HIS236
HIS236, TYR248
4a
4b
4c
4d
4e
4f
4a
4b
4c
4d
4e
4f
HIS226, HIS230, HIS236
HIS226, HIS230, HIS236,
TYR248
GLY170, ASP168
TYR35, MET109, ASP168
TYR35, LYS53, MET109
4g
4g
HIS226, HIS230, HIS236, TYR248, ALA191
tein MMP-9 with a binding energy of −9.3 kcal/mol forming 5 hy-
drogen bonds. The rest of the synthesized compounds interacted
with MMP-9 protein with binding energies ranging between −8.6
to −7.8 kcal/mol (Fig. 7). The interaction energies of each molecule
with the number of hydrogen bonds formed with different residues
of the appropriate target proteins are presented in Table 7. In the
present study, P38 MAPk was used as a target for synthesized
compounds to correlate their anticancer effects. P38 MAPk acts
as a measure of mitochondrial respiration, indirectly correspond-
ing to cellular toxicity. By inhibiting P38 MAPk, the effect of in-
hibitors on cell proliferation can be measured [36]. The preventive
mechanisms behind such cancer-preventive effects may range from
the inhibition of genotoxic effects, increased antioxidants and anti-
inflammatory activity, inhibition of proteases and cell proliferation,
protection of intracellular communications to modulate apoptosis,
and signal transduction pathways [36,56]. Similarly, Matrix metal-
loproteinases (MMPs) play important roles in the interaction be-
tween inflammatory cells [37]. MMP9, along with other MMPs, is
expressed in inflammatory cells and involved in the regulation of
inflammation and other tissue responses [57,58] by deteriorating
the extracellular matrix (ECM) proteins and help in the remodel-
ing of the extracellular matrix [39]. MMP-9 also has crucial roles
in several cancers associated with inflammation [38]. Imbalance in
the activation and inhibition of MMPs plays a vital role in cancer
pathophysiology [39,59]. Inhibitors of metalloproteinase (TIMP) can
be used to control the elevated expression of MMP-9 to control
pathological conditions such as cancer and inflammation [39].
Supporting information
Materials and method & Spectroscopic data (IR, 1H NMR, 13C
NMR, and Mass spectrometry) along with spectra of the synthe-
sized compounds have been provided in the supporting informa-
tion file.
Declaration of Competing Interest
The authors declare that there is no conflict of interest regard-
ing the publication of this work.
CRediT authorship contribution statement
S.H. Sukanya: Methodology, Investigation, Writing – original
draft. Talavara Venkatesh: Investigation, Supervision, Writing – re-
view & editing. S.J. Aditya Rao: Writing – review & editing, Soft-
ware. Muthipeedika Nibin Joy: Writing – review & editing.
Acknowledgment
The authors are thankful to the Chairman, Department of
Chemistry, Kuvempu University, Shankaraghatta, for providing the
laboratory facilities. The authors are also thankful to SAIF, Mysore
University, and Karnataka University, Dharawad, for providing the
spectral data.
Supplementary materials
4. Conclusion
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.molstruc.2021.131324.
In summary, we have successfully synthesized new (4-
substituted-phenyl)-1,5-dihydro-2H-pyrimido[4,5-d][1,3]thiazolo
[3,2a]-pyrimidine-2,4(3H)-dione derivatives in good to excel-
lent yield and evaluated their in vitro cytotoxicity and anti-
inflammatory effects. Among the newly synthesized molecules,
the compounds 4f and 4g were identified as the most active
anticancer agents, whereas the compounds 4a and 4g were found
to exhibit promising anti-inflammatory activity. This was also sup-
ported by the in silico interaction studies. SAR studies revealed the
importance of electron-withdrawing groups in enhancing the po-
tency of these more active compounds. In silico ADME-toxicology
results indicated that all the compounds are nontoxic and good
oral bioavailability and drug-likeness score indicated that they are
suitable as drug-leads. From in silico molecular docking results, it
was found that the effective anticancer compounds 4f and 4g have
bound with P38 MAPk with a minimal binding energy of −8.7 and
−8.4 kcal/mol, respectively, while the effective anti-inflammatory
compounds, 4g, and 4a have bound with MMP-9 protein with a
minimal binding energy of −9.3 and −8.6 kcal/mol, respectively.
Further studies on lead optimization are being carried out in our
laboratory and will be reported in due course.
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