Synthesis, structure prediction, pharmacokinetic properties, molecular docking and antitumor activities of some novel thiazinone derivatives

Article abstract of DOI:10.1039/c5nj01369k

A novel series of thiazinone derivatives were obtained from unexpected cyclization of dimethyl acetylenedicarboxylate (DMAD) and diethyl acetylenedicarboxylate (DEAD) with corresponding 3-alkyl-2,6-diarylpiperidin-4-one thiosemicarbazones in dry methanol

Full text of DOI:10.1039/c5nj01369k

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DOI: 10.1039/C5NJ01369K
Journal Name
ARTICLE
Synthesis, structure prediction, pharmacokinetic properties,
molecular docking and antitumor activities of some novel
thiazinone derivatives.
Received 00th January 20xx,
Accepted 00th January 20xx
Selvam Athavan Alias Anand,a Chandrasekaran Loganathan,a Nisha Susan Thomas,b Kuppusamy
DOI: 10.1039/x0xx00000x
Saravanan,a Antony Therasa Alphonsaa and Senthamaraikannan Kabilan*,a
www.rsc.org/
A novel series of thiazinone derivatives were obtained from unexpected cyclization of dimethyl acetylenedicarboxylate
(DMAD) and diethyl acetylenedicarboxylate (DEAD) with corresponding 3–alkyl–2,6–diarylpiperidin–4one
thiosemicarbazones in dry methanol, without catalyst under mild conditions. The structures of newly synthesized
compounds were established on the basis of FT–IR, HR–Mass, 1H–NMR, 13C–NMR, 1H–1H COSY, 1H–13C COSY, DEPT–135,
and HMBC spectral techniques. From the 1H NMR, all newly synthesized compounds 17–24 were found to adopt chair
conformation. The theoretical studies were carried out using Schrödinger software suite for the structure prediction,
biochemical properties investigation and docking studies of all novel compounds. In order to provide the antitumor
activity, all the novel compounds were screened in vitro for their cytotoxicity and apoptosis activity against Hep G2 human
liver cancer cell line. The biological analysis revealed that the newly synthesized compounds have good/moderate
inhibitory activity against the tested cell line.
1. Introduction
In the present work, we report the way of reactivity
Recent advances in biochemistry and medicinal chemistry
allow access to do wonders in pharmaceutical applications. To
understand the principles of medicinal chemistry, it is
necessary to know about the physicochemical properties
including possible biological activity of the chemical
compounds. Organic compounds being continue to be
important in the development of new agents for treating
diseases. However, heterocyclic compounds with increasingly
specific pharmacological activities are clearly dominant. Even
in the field of modern medicinal chemistry, heterocyclic
alkaloids like morphine derivatives are the active ingredients in
between
3–alkyl–2,6–diarylpiperidin–4–one
thiosemicarbazone derivatives and DMAD/DEAD; an electron–
deficient alkyne diester which is used as dienophile and / or
dipolarophile in cycloaddition reactions.16
The molecular
–
20
structure of the resulting heterocycles was investigated using
spectral techniques and theoretically by HOMO-LUMO energy
gap calculations. To understand the fundamental drug−like
properties of the newly synthesized compounds,
pharmacokinetic properties predictions were carried out based
on Lipinski’s rule of five. The docking studies were performed
to find the mode of interactions between the compounds and
the selected protein. Both the pharmacokinetic properties
predictions and the docking studies were examined using
Maestro v 9.3.5 21 of Schrödinger software suite, 2012.
–
4
many natural remedies.1 Modifications in drug motifs using
heterocycles can also provide favorable biological properties.
We are actively doing research in the area of drug discovery
–
and synthesis of novel heterocycles.5 8 Our research is focused
The recent anticancer drug research indicates that the
piperidinone derivatives exhibit potent and sufficient activity
against cancer cell lines.22 All the newly synthesized molecules
were evaluated for their cytotoxicity on human liver cancer
cell line Hep G2 through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyl tetrazolium bromide, a yellow tetrazole) assay. The
apoptotic activity against Hep G2 was also carried out and the
morphological studies were performed using Acridine Orange
(AO)/Ethidium bromide (EB) staining.
on the design and synthesis of 3–alkyl–2,6–diarylpiperidin–4–
ones derivatives with heterocyclic systems such as oxime
ethers, thiadiazolines, imidazoles/benzotriazoles, thiones,
piperazine, morphine, benzimidazole exhibit diverse biological
–
15
activities.9
a.Drug Discovery Lab, Department of Chemistry, Annamalai University,
Annamalainagar, Tamilnadu – 608002, India.
b.Department of Bio-Chemistry and Bio-Technology, Annamalai University,
Annamalainagar, Tamilnadu – 608002, India.
Email: profskabilanau@gmail.com, Tel: +91 94439 24629
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
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partition coefficient between octanol and water V(iQewPAlrotigclPe oOn/lwine)
be less than 5. The compounds which have more than one
2. Experimental
2.1. Chemistry
DOI: 10.1039/C5NJ01369K
violation of these rules are not considered as orally active
molecule. The properties such as percentage of human oral
absorption, aqueous solubility, IC50 value for blockage of HERG
K+ channels and blood brain barrier permeability were also
predicted to know about the basic bioactivity of the compounds.
2.2.3 Docking Studies
The reaction between thioamides and alkyne diester was widely
emphasized for the synthesis of either thiazin–4–ones or
thiazolidin–4–ones.23–28 Thiazinone and thiazolidinone based
heterocycles are the most common motifs found in drug
design. The derivatives of thiazinone and thiazolidinone are of
much interest because of their miscellaneous biological
The critical interactions between Murine double minutes
(MDM2) and p53 proteins have been proved as a promising
target for anticancer therapy.42 The MDM2 is considered as
bonafide oncogene, which suppresses the significant activity of
the natural tumor suppressor p53. It was observed that the
growth of cancer cells was arrested by inhibiting the over
expression of MDM2 which demonstrate the significant
activation of p53.43 The 3D co–ordinates of crystallographic
structure of MDM2 protein complex44 (PDB ID: 4ODE) was
downloaded from Brookheaven protein Data Bank
(www.rscb.com). The protein complex was pre–processed and
prepared by Protein Preparation Wizard45 in Maestro of
Schrödinger software. The minimization of the complex was
continued using OPLS–2005 (Optimized Potential for Liquid
Simulations) force field46 until the root mean square deviation
(RMSD) reached the value of 0.3 Å.
The 2D structures of compounds 17-24 were imported from
the project table and the structures were minimized and
geometrically refined using Ligprep47 module. Conformers
were generated using torsional search method with distance
dependent dielectric solvation treatment and OPLS–2005 force
field. The extra precision (XP) mode of docking was used to
find the best fit molecules in the active site of MDM2 protein
using Glide48 application of Schrödinger software suite.
2.3. Biological Studies
activities
such
as
anticancer,29
antimicrobial,30
anticonvulsant,31 antituberculosis,32 and anti–HIV.33 Thiazinone
and thiazolidinone derivatives also act as α–Amino–3–
hydroxy–5–methyl–4–isoxazolepropionic acid (AMPA) receptor
antagonist34 and inhibitors of bacterial enzyme Mur–B35
respectively.
The starting material 3–alkyl–2,6–diarylpiperidin–4–ones
were prepared in good yields through consecutive steps as
reported in the literature.36,37 The thiosemicarbazone
derivatives were prepared in acidic methanol medium by
treating thiosemicarbazide with substituted piperidones under
reflux condition. These upon recrystallisation in methanol gave
pure
compounds.38
The
reaction
between
and
thiourea/thiosemicarbazone/thioamide
derivatives
electron–deficient alkyne diester is the convenient and
effective method to synthesize thiazolidinone or thiazinone
derivatives. We have considered a trial reaction of 3–alkyl–
2,6–diarylpiperidin–4–one thiosemicarbazone derivatives with
DMAD/DEAD to investigate in detail about the reactivity.
2.2. Computational Studies
The theoretical calculations reported in this work were
performed on
a Dell workstation equipped with Xeon
processor E3–1225, V2 quardcore, 3.20 GHz personal
computer with 8 GB total RAM and with Schrödinger software
suite, LLC, New York, 2012.
2.3.1 Cytotoxicity
Human hepatoma cell line, Hep G2 were obtained from the
National Centre for Cell Science, Pune, India. The cytotoxic
effect of the synthesized compounds 17-24 on Hep G2 liver
cancer cell line was evaluated through MTT dye reduction
assay as described earlier.49 The tested compounds were
dissolved quantitatively in dimethylsulfoxide (DMSO, Sigma,
USA) and diluted to make stock solution. Hep G2 cells were
seeded at a density of 5 x 103 cells/well into 96 well plates.
After 24 h, the cells were treated with various concentrations
of the compounds 17-24 in the range of 10-100 μM and
incubated for 24 h and 48 h as indicated. The cells were then
assayed by the addition of 20 μL of MTT (5 mg/mL in
phosphate-buffered saline) per well and incubated in dark at
37°C for 3 h. The purple formazan crystals formed after 3 h
were dissolved in 100 μL of DMSO after aspirating the MTT
and incubated for further 10 minutes. The mitochondrial
dehydrogenase in viable cells that reduces MTT to blue
formazan product was measured at 570 nm (measurement)
and 630 nm (reference) using a 96 wells plate reader (Bio-Rad,
Hercules, CA, USA). Data were collected from six independent
experiments and used to calculate the respective means. The
2.2.1 Identification of Stable Isomer
The quantum chemical calculations of compounds 17 and 25
were performed by using Schrödinger software with Jaguar39
application. The structures of the compounds 17 and 25 were
fully optimized in vacuum using density functional theory (DFT)
method at B3LYP and M06 hybrid functionals along with 6–
31G**, 6–311G**, and 6–311G–3DF–3PD basis sets. Highest
occupied molecular orbital (HOMO) energies, lowest
unoccupied molecular orbital (LUMO) energies and the energy
gap (LUMO-HOMO) of two compounds were calculated and
compared. The structure with maximum energy gap was
considered as a stable compound.
2.2.2 Pharmacokinetic Properties prediction
The 2D structures of compounds 17–24 were subjected to a
computational program using Qikprop40 module of Schrödinger
software for the insilico determination of pharmacokinetic
properties. A preliminary test of the drug–likeness of the
compounds was calculated in accordance with Lipinski’s rule of
five.41 To obey the Lipinski’s rule of five, the compounds
requires molecular weight (mol_MW) of less than 500 amu, no
more than 5 and 10 hydrogen bond donors (Donor HB) and
hydrogen bond acceptors (Accpt HB) respectively, and the
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percentage of inhibition was calculated from the data, using obtained after acid/base workup and recrystallised by slow
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DOI: 10.1039/C5NJ01369K
evaporation method in ethanol gives pure compound.
the formula:
2.5.2 General procedure for the preparation of compounds 9-16
[(Mean absorbance of treated cells)/(Mean absorbance of sham
control cells)100].
2.3.2 Assessment of unstained cell morphological assay
To the completely dissolved solution of substituted 3–alkyl–
2,6–diphenylpiperidin–4–one (1.0 mmol) in methanol, 0.2 mL
Hep G2 cells were grown on glass cover slip (22×22 mm) of conc. HCl and methanolic solution of thiosemicarbazide (1.0
placed in six well plates at a density of 5×105 cells/well and mmol) was added dropwise with stirring. The reaction mixture
incubated for 24 h before treatment with the IC50 (50% was refluxed with water condenser for 2 h. After completion,
Inhibitory concentration after treatment) values of compounds the reaction mixture was cooled to room temperature and the
17-24. The medium was subsequently removed from each well solid separated was filtered. The crude product was
of the sham control and the compounds treated Hep G2 cells recrystallised from methanol.
2.5.3 General procedure for the synthesis of compounds 17–24
after 24 h and/or 48 h incubation. The cover slips were then
inverted and placed over micro slides. The gross morphological
changes in the compounds treated and sham control cells
were observed using a differential interference phase contrast
light microscope (Axio Scope A1, Carl Zeiss, Jena, Germany)
To a warm solution of substituted 3–alkyl–2,6–diarylpiperidin–
4–one thiosemicarbazones (1.0 mmol) in methanol,
methanolic solution of DMAD (1.0 mmol) /DEAD (1.0 mmol)
was added drop wise with stirring. The reaction mixture was
allowed to stirred at 60°C for 2 h. The completion of reaction
was confirmed by TLC and the reaction mixture was cooled to
and photographed at 40X magnification
.
2.3.3 Acridine Orange /Ethidium bromide double staining
To characterize the cell apoptosis as a result of the synthesized room temperature. The yellow solid obtained was filtered and
compounds, Acridine Orange (AO)/Ethidium bromide (EB) washed with warm methanol.
(E)-methyl 2-(2-(1,3-dimethyl-2,6-diphenylpiperidin-4-
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (17).
staining was performed to detect the apoptotic cell
morphology as described by Spector et al.50 Equal volumes of
AO (100μg/mL) and EB (100μg/mL) in phosphate-buffered
saline (PBS) were prepared for staining. Cells (Hep G2) were
grown on glass cover slips in six well plates (5×105 cells/well)
for 24h. The cells were then incubated with the IC50 dose of all
newly synthesized compounds 17-24 for 24 h. After incubation
the medium was discarded and the cells were washed with
PBS. The cells were then trypsinized, placed on a glass slide,
Pale yellow powder, yield: 87%. M.p. 183-185 °C; 1H NMR (400
MHz, CDCl3, δ ppm) 0.87 (d, 3H), 1.69 (s, 3H), 2.37 (t, 1H), 2.75 (m,
1H), 2.90 (d, 1H), 3.22 (d, 1H), 3.53 (d, 1H), 3.85 (s, 3H), 6.86 (s, 1H),
7.44 – 7.26 (m, 10H). 13C NMR (125 MHz, CDCl3) δ: 12.81, 38.61,
41.47, 45.57, 52.57, 69.94, 77.90, 116.08, 127.21−128.69, 142.40,
142.90, 144.16, 157.47, 165.44, 166.44, 171.10. HRMS (ESI/(M+H)+)
calcd for C25H26N4O3S 463.1805 found 463.1821.
stained with AO/EB and examined using
a fluorescent (E)-methyl 2-(2-(2,6-bis(4-methoxyphenyl)-3-methylpiperidin-4-
microscope with an UV filter (450-490 nm). The cells reflecting
pathological changes were observed, calculated and
photographed at 40X magnification (Axio Scope A1, Carl Zeiss,
Jena, Germany).
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (18).
Pale yellow powder, yield: 76%. M.p. 211-213 °C; 1H NMR (400
MHz, DMSO-d6, δ ppm) 0.92 (d, 3H), 3.17 (t, 1H), 3.57 (m, 1H), 3.71
(s, 1H), 3.77 (s, 3H), 3.79 (s, 6H), 4.35 (d, 1H), 4.58 (d, 1H), 6.68 (s,
1H), 7.74 – 6.98 (m, 8H). 13C NMR (125 MHz, DMSO-d6) δ: 11.87,
31.92, 40.19, 52.44, 55.19, 58.79, 65.51, 114.44, 126.80−130.39,
142.83, 160.41, 165.60, 165.68, 165.89. HRMS (ESI/(M+H)+) calcd
for C26H28N4O5S 509.1859 found 509.1895.
2.4. Instrumentation
The melting points were determined in open capillary tubes
and are uncorrected. Infra–red spectra were recorded on
Thermo Nicolet FT–IR model iS5 spectrophotometer using KBr
pellet. The NMR spectra were recorded at 400 MHz and 300
MHz Bruker instruments using Tetramethylsilane (TMS) as an
(E)-ethyl-2-(2-(1,3-dimethyl-2,6-diphenylpiperidin-4-
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (19).
internal standard. Deuterated chloroform/deuterated DMSO Pale yellow powder, yield: 83%. M.p. 196-198 °C; 1H NMR (400
was used to record all NMR spectra and the chemical shifts are MHz, CDCl3, δ ppm) 0.87 (d, 3H), 1.34 (t, 3H), 1.70 (s, 3H), 2.36 (s,
reported in δ units (parts per million) relative to the standard. 1H), 2.76 (s, 1H), 2.89 (s, 1H), 3.22 (s, 1H), 3.53 (d, 1H), 4.30 (q, 2H),
Mass spectra were recorded on VG7070H and Thermo Nicolet 6.85 (s, 1H), 7.41 – 7.26 (m, 10H). 13C NMR (125 MHz, CDCl3) δ:
Exactive Plus mass spectrometers. All reactions were 12.78, 14.17, 38.56, 41.42, 45.51, 61.68, 69.91, 77.89, 116.59,
monitored by thin layer chromatography using silica gel 127.21−128.66, 142.04, 157.80, 165.62, 165.94, 170.90.
precoated aluminium sheets of Merck TLC 60 F254 and C26H28N4O3S, MS: 477.195 ([M+H]+).
(E)-methyl 2-(2-(2,6-bis(4-chlorophenyl)-3-methylpiperidin-4-
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (20).
visualized in UV light chamber. All reactions were carried out
using analytical grade solvents without further purification.
2.5. Synthetic Procedures
Yellow powder, yield: 82%. M.p. 205-207 °C; 1H NMR (300 MHz,
DMSO-d6, δ ppm) 0.93 (d, 3H), 3.21 (t, 1H), 3.63 (m, 1H), 3.72 (d,
1H), 3.77 (s, 3H), 4.46 (d, 1H), 4.69 (d, 1H), 6.68 (s, 1H), 7.90 – 7.52
(m, 8H). 13C NMR (100 MHz, DMSO-d6) δ: 11.75, 31.84, 52.36, 58.73,
65.34, 114.42, 128.51−134.63, 142.78, 160.55, 164.92, 165.57,
165.79. C24H22Cl2N4O3S, MS: 517.086 ([M+H]+).
2.5.1 General procedure for the preparation of compounds 1–8
Mannich condensation of appropriate ketones, aldehydes and
ammonium acetate or methyl amine in the ratio of 1:2:1
respectively, in the medium of 95% ethanol gives substituted
3–alkyl–2,6–diarylpiperidin–4–ones. The crude product was
[Type text]
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(E)-ethyl 2-(2-(2,6-bis(4-chlorophenyl)-3-methylpiperidin-4-
elimination of an alcohol molecule. The cyclization of this
View Article Online
intermediate has been claimed for twoDOdiI:ff1e0r.1e0n3t9/sCt5rNuJc0t1u3r6e9sK,
either i) α–cyclization resulting in the formation of a six–
membered thiazin–4–one ring or ii) β–cyclization resulting in
the formation of a five–membered thiazolidin–4–one ring (Fig.
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (21).
Yellow powder, yield: 78%. M.p. 217-219 °C; 1H NMR (300 MHz,
DMSO-d6, δ ppm) 0.93 (d, 3H), 1.25 (t, 3H), 3.17 (t, 1H), 3.60 (m,
1H), 3.76 (d, 1H), 4.23 (q, 2H), 4.45 (d, 1H), 4.68 (d, 1H), 6.65 (s, 1H),
7.88 – 7.52 (m, 8H). 13C NMR (100 MHz, DMSO-d6) δ: 11.79, 13.95,
31.89, 58.81, 61.31, 65.40, 114.75, 128.55−134.72, 142.69, 160.72,
164.91, 165.33, 165.64. C25H24Cl2N4O3S, MS: 531.101 ([M+H]+).
(E)-methyl 2-(2-(2,6-bis(4-chlorophenyl)-3-ethylpiperidin-4-
1
). It has been observed from the spectral analysis that the
intermediate is actually participated in α–cyclization leading to
the formation of six–membered thiazin–4–ones
regioselectively (Scheme 1).51-53
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (22).
Yellow powder, yield: 77%. M.p. 227-229 °C; 1H NMR (300 MHz,
DMSO-d6, δ ppm) 0.91 (t, 3H), 1.46 (q, 2H), 3.16 (t, 1H), 3.60 (s, 1H),
3.74 (s, 3H), 4.60 (m, 1H), 4.71 (m, 1H), 6.69 (s, 1H), 7.90 – 7.52 (m,
8H). 13C NMR (100 MHz, DMSO-d6) δ: 10.31, 18.46, 32.04, 45.22,
52.37, 58.69, 63.58, 114.41, 128.46−138.68, 142.85, 160.48, 163.59,
165.56, 165.78. C25H24Cl2N4O3S, MS: 531.101 ([M+H]+).
(E)-ethyl 2-(2-(2,6-bis(4-chlorophenyl)-3-ethylpiperidin-4-
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (23).
Yellow powder, yield: 74%. M.p. 232-234 °C; 1H NMR (300 MHz,
DMSO-d6, δ ppm) 0.91 (t, 3H), 1.25 (t, 3H), 1.47 (m, 2H), 3.77 (d,
1H), 4.23 (q, 2H), 4.59 (s, 1H), 4.69 (d, 1H), 6.65 (s, 1H), 7.84 – 7.52
(m, 8H). 13C NMR (100 MHz, DMSO-d6) δ: 10.33, 13.89, 18.47, 32.04,
45.26, 58.65, 61.26, 63.57, 114.78, 128.48−134.70, 142.60, 160.32,
163.55, 165.20, 165.59. C28H32Cl2N4O3S, MS: 545.117 ([M+H]+).
(E)-methyl 2-(2-(3-isopropyl-2,6-diphenylpiperidin-4-
Fig. 2 Formation of six membered thiazinone from the unstable five
membered thiazolidinone
On the other hand, there is a possibility of thiazinone
formation by the attack of methoxide ion on cyclic amide
carbonyl, leading to the unstable thiazolidinone ring which will
undergo a ring opening and consequent ring closure involving
the other ester carbonyl to give the six membered
thiazinone54,55 as the final product (Fig. 2).
ylidene)hydrazinyl)-4-oxo-4H-1,3-thiazine-6-carboxylate (24).
Pale yellow powder, yield: 85%. M.p. 201-203 °C; 1H NMR (400
MHz, DMSO-d6, δ ppm) 0.98 (d, 3H), 1.113 (d, 3H), 1.672 (s, 2H),
2.30 (t, 1H), 2.68 (d, 1H), 3.61 (d, 1H), 3.76 (s, 3H), 3.93 (d, 1H), 3.98
(d, 1H), 6.62 (s, 1H), 7.53 – 7.26 (m, 10H). 13C NMR (125 MHz,
DMSO-d6) δ: 17.42, 20.82, 26.93, 31.53, 52.31, 54.09, 59.75, 64.86,
113.39, 126.62−128.24, 142.60, 165.98, 166.47. C26H28N4O3S, MS:
477.195 ([M+H]+).
3.2. Spectral Analyses
The structure of newly synthesized compounds was supported
by spectral analyses such as FT–IR, HR–Mass, 1D and 2D NMR
spectra. The numbering pattern followed for compounds 17–
24 to explain the spectra was given in Fig. 3. The 1H NMR
spectrum splitting patterns are noted as broad singlet (bs),
singlet (s), doublet (d), triplet (t), quintet (q) and multiplet (m).
Compound 17 was considered as a representative for the
synthesized compounds and the 2D NMR spectra were
3. Results and Discussions
3.1. Reaction Mechanism
The first step of the mechanism involves the conjugate
addition of sulfur atom onto the triple bond of the acetylene
and the resulting intermediate undergoes intra–molecular
condensation via aminolysis of the ester group followed by the
recorded for it to elucidate the structure
.
3.2.1 FT–IR and HR–Mass spectral analyses
FT–IR spectrum (Fig. S1) recorded for the representative
compound 17 exhibits four sharp intense bands at 1733, 1702,
1642 and 1618 cm–1 characteristics of ester carbonyl, amide
carbonyl and imino group of thiazinone ring and imino group
of piperidine respectively, whereas the −NH− in 9th position
showed a broad band at 3389 cm–1. Mass spectra were
recorded for the new compounds and the observed peaks with
mass values (M+H)+ confirmed the formation of the products
.
3.2.2 1H, 13C and 2D NMR spectral analyses of the compound 17
1
In the H NMR (Fig. S2) spectrum, a sharp singlet at 1.69 ppm
with three protons integral corresponds to methyl protons H–
7a attached to the piperidones ring nitrogen. A doublet at 0.87
ppm is corresponding to methyl protons H–3’a attached to
carbon 3 and it shows HOMO correlation with the multiplet
signal at 2.75 ppm obviously due to H–3a proton in 1H−1H
Fig. 1 Plausible mechanism of the reaction between thioamide and
DMAD.
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COSY spectrum (Fig. S5). Moreover, the methoxy protons H–h correlation with H–6a proton (3.22 ppm). A triplet appeared
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DOI: 10.1039/C5NJ01369K
in the ester group of compound 17 resonate as a sharp singlet at 2.37 ppm with one proton integral corresponding to H–5a
at 3.85 ppm. The aromatic proton signals of two phenyl rings proton is confirmed by HOMO correlation with H–6a (3.22
of the compound 17 appear in the region of 7.44 to 7.27 ppm ppm) and H–5e (3.53 ppm). The large coupling constants were
as multiplet. A sharp singlet appeared at 6.86 ppm with one observed between H2 & H3 protons (J = 10.0 Hz) and H5 & H6
proton integral was assigned to methine proton H–e present in protons (J = 10.8 Hz) which suggested that the piperidone ring
Scheme 1. The reaction between 3–alkyl–2,6–diarylpiperidin–4–one
thiosemicarbazones and acetylene diesters.
exist largely in normal chair conformation with equatorial
the thiazinone ring. For compound 17, one of the two benzylic
protons appears as a doublet at 3.22 ppm is assigned for H–6a
proton and the other doublet at 2.90 ppm is assigned for H–2a
orientation of C–3 methyl and aryl groups.
In 13C NMR spectrum (Fig. S3), the signals at 77.9
, 69.9, 45.5
and 38.6 ppm in the aliphatic region are assigned to C–2, C–6,
C–3 and C–5 carbons of the piperidine ring based on one bond
correlations with H–2a (2.90 ppm) H–6a (3.22 ppm) and H–3a
(2.75 ppm) in the 1H–13C COSY spectrum (Fig. S6) and the
negative peak observed at 38.5 ppm in the DEPT-135 spectrum
1
proton as the later has correlation with H–3a in H–1H COSY.
The doublet at 3.53 ppm with one proton integral
corresponding to H–5e proton is confirmed by 1H–1H
Table 1. 1H–1H COSY, 1H–13C COSY and HMBC correlations of
compound 17
Correlations (ppm)
1H Chemical
shifts (ppm)
1H–1H
COSY
1H–13C
HMBC
COSY
0.87
(d, 3H, H–3’a)
77.90, 45.57, 12.81,
171.10
2.75 (m)
12.81
41.47
38.61
45.57
77.90
69.94
38.61
1.69
(s, 3H, H–7a)
–––––
77.90, 69.94
2.37
(t, 1H, H–5a)
3.53 (d),
3.22 (d)
69.94, 171.10, 144.16
12.81, 171.10, 77.90
2.75
(m, 1H, H–3a)
2.90 (d),
0.87 (d)
Fig. 3 Numbering pattern of compound 17 followed for the spectral
explanations.
2.90
(d, 1H, H–2a)
69.94, 45.57, 41.47,
12.81, 128.69, 142.90
2.75 (m)
3.22
(d, 1H, H–6a)
3.53 (d),
2.37 (t)
(Fig. S4) for C–5 carbon. The 2D NMR correlations of
compound 17 are given in Table 1. The methylene carbon C–5
127.21
1
is also confirmed in H–13C COSY by its cross peak with H–5a
3.53
(d, 1H, H–5e)
3.22 (d),
2.37 (t)
45.57, 171.10
(2.37 ppm) and H–5e (3.53 ppm). The signal at 41.4 ppm is
assigned to C–7 carbon as observed by the one bond
3.85 (s, 3H, H–h)
6.86 (s, 1H, H–e)
–––––
–––––
52.57
116.08
166.44
116.08, 165.44, 142.40
1
correlation with H–7a (1.69ppm) in H–13C COSY and multiple
128.69 –
127.21
77.90, 69.94, 127.21 –
128.69, 142.90, 144.16
bond correlation with H–2a (2.90 ppm) in HMBC spectrum (Fig.
S7). The signal at 12.8 ppm in the HMBC is assigned to methyl
7.44 – 7.26 (m)
–––––
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carbon C–3’ attached to the C–3 as it shows cross peak with H– 3.3. Computational Results
View Article Online
In HOMO and LUMO calculations, the resDuOltIs: 1o0b.1t0a3in9/eCd5NuJs0in13g6a9Kll
the levels of theories indicated that the energy gap of the
compound 17 with thiazinone ring were slightly higher than
3’a (0.87 ppm) and α correlation with H–3a (2.75 ppm) and β
correlation with H–2a (2.90 ppm). Moreover, the signal at 52.5
ppm is assigned to methyl carbon C–h of the ester group is as
Fig. 4 The expansions of HMBC spectrum of compound 17.
evidenced by one bond correlation with the corresponding
methyl protons H–h (3.85ppm).The signal nearer to aromatic
region at 116.0 ppm has one bond correlation with methine
proton H–e present in the thiazinone ring (6.86ppm) and it is
assigned for C–e carbon. The signal at 171.1 ppm shows
multiple bond correlation with 2.37 ppm (H–5a), 3.53 ppm (H–
5e), and also with 2.75 ppm (H–3a), 0.87 ppm (H–3’a) in the
HMBC spectrum is assigned for C–4 carbon. The quaternary
carbon signal at 142.4 ppm shows HMBC correlation with H–e
(6.86 ppm) and it is assigned for C–f carbon. The less intense
quaternary carbon signal at 157.4 ppm is assigned for C–b
carbon.
the compound 25 with thiazolidinone ring and hence
compound 17 was considered as a stable form for the
representative compound. The energy gap values of compounds 17
and 25 are given in Table 2. The pictorial representation of
HOMO and LUMO of all levels is given in the supplementary
data (Table S1).
Table 2. LUMO-HOMO energy gap of compounds 17 and 25.
LUMO-
HOMO
energy
LUMO-
HOMO
energy
Energy
difference
between
Level of Theories
/ basis set
gap of 17 gap of 25 17 and 25
(eV)
(eV)
(eV)
B3LYP/6–31G**
B3LYP/6–311G**
M06/6–31G**
4.05590
4.03328
0.02262
4.07044
4.66615
4.72981
4.04345
4.64301
4.65577
0.02699
0.02314
0.07404
M06/6–311G**
M06/6–311G–
3DF–3PD
7.47820
7.42291
0.05529
The expansions of HMBC spectrum were displayed in Fig. 4
.
The 13C signal at 166.4 ppm is assigned for the ester carbonyl
group C–g based on the β–correlation with the proton at 3.85
ppm (H–h). The signal of C–g (166.4 ppm) does not show any
other correlation with the proton peak at 6.86 ppm (H–e),
whereas the signal at 165.44 is assigned to amido carbonyl
carbon C–d shows α–correlation with the proton signal at 6.86
ppm (H–e). Therefore, these observations unequivocally
confirm the cyclization of acetylenes with 3–alkyl–2,6–
diarylpiperidin–4–one thiosemicarbazone derivatives to give
six–membered thiazin–4–ones and hence the formation of
compounds 25–32 was ruled out.
Fig. 5 Docking poses of A) Compound 19 and B) Compound 20
with MDM2 protein, PDB ID: 4ODE.
The Lipinski’s rule of five values of compounds 17–24 indicate that
the compounds are endowed with drug like properties.
Compounds 17
rule of five. All other compounds (18
,
19, and 24 showed no violation on Lipinski’s
20 21, and 22) showed
,
,
one violation except compound 23, which showed 2 violations
owing to its partition coefficient value between octanol and
water is more than 5 and the molecular weight is greater than
6 | J. Name., 2012, 00, 1-3
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500 amu. The drug−like prediction results by Qikprop are The docking results clearly indicate that the watVeierwmAroticlleecOunlleinse
DOI: 10.1039/C5NJ01369K
tabulated in Table 3. The tested compounds have satisfactory present in the active site of MDM2 protein plays an important
percentage of human oral absorption except compounds 18 role in binding. All the tested compounds display interactions
and 23 which have less than 70%. Predicted aqueous solubility with one or two water molecules (Fig. S37). The interactions
(QPlogS) parameter indicated that the compounds 17
and 24 possess permissible values and the chloro substituted Compounds 17
compounds (20 21 22, and 23) are having poor aqueous compounds 19 and 20 exhibited good interactions with an
,
18
,
19 between 4ODE and the compounds are tabulated in Table 4
.
,
19, 20 and 24 have good glide score and the
,
,
solubility. The prediction of blood brain barrier permeability important residue HIE 96 by π−π stacking which is essential for
(QPlogBB) for the tested compounds was assessed and all the the inhibitory activity of MDM2.56 These π−π stacking
compounds were predicted to have acceptable values. The IC50 interactions were performed by the phenyl ring attached to
value of HERG K+ channel blockage (QPlogHERG) was also the sixth position of the piperidyl ring. Compound 20 also
predicted and the results showed that all the tested showed π−cation interaction with MET 6 and hydrogen bond
compounds have moderate range of values.
interactions with two water molecules. The interactions
Table 3. Pharmacokinetic properties of compounds 17–24
between the MDM2 protein and the compounds 19 and 20 are
Factors of Lipinski’s rule of five
Pharmacokinetic properties
Percent
Comp
Donor
HB
Accpt
HB
Rule
of
Human Oral
Absorptiona
(> 80 high, <
25 poor)
77.765
QPlogSb
(–6.5 to
0.5)
mol_MW
(< 500)
QPlogPo/w
(< 5)
QPlogHERGc
QPlogBBd
(below –5)
(–3 to 1.2)
(< 5)
(< 10)
Five
17
18
19
20
21
22
23
24
462.565
508.591
476.592
517.429
531.456
531.456
545.482
476.592
1
2
1
2
2
2
2
2
9
3.375
3.525
3.817
4.451
4.660
4.647
5.022
4.009
0
1
0
1
1
1
2
0
–5.717
–6.263
–6.241
–7.860
–7.627
–7.451
–7.915
–6.148
–7.816
–7.713
–8.043
–7.935
–7.768
–7.752
–7.906
–7.869
–1.186
–1.379
–1.242
–1.042
–0.930
–0.923
–1.021
–0.894
10
9
66.254
81.491
8.5
8.5
8.5
8.5
8.5
70.759
73.580
73.520
63.080
86.528
aPercentage of human absorption, bPredicted aqueous solubility; S in mol/L,
cPredicted IC50 value for blockage of HERG K+ channels, dPredicted blood
brain barrier permeability
shown in Fig. 5. The tested compounds 18 and 23 form
hydrogen bond interactions with GLN 59 and TYR 67
respectively.
Docking studies was carried out to evaluate the binding affinity
and the interactions between the synthesized compounds and
the MDM2 protein (PDB ID: 4ODE). The docking score of the
compounds 17-24 varies from -8.427 to -7.027. The evdw and
ecoul are the predicted van der Waals’ interaction and
electrostatic interaction energies between ligand and the
protein.
3.4. Antitumor Studies
3.4.1 Cytotoxicity Results
The cytotoxicity of the tested compounds 17-24 were
evaluated against human Hep G2 cell line in various
concentrations viz. 10 μM, 20 μM, 30 μM, 40 μM, 50 μM, 60
μM, 70 μM, 80 μM, 90 μM, and 100 μM. Fig. 6 shows the
inhibitory effect of the synthesized compounds 17-24 on Hep
G2 liver cancer cells after 24 h and 48 h respectively.
Treated cells showed shrinkage in volume of cells, membrane
blebbing and loss of cell adhesion. The IC50 values of the novel
compounds ranges from 10 to 100 μM and tabulated in Table
Table 4. Docking results of compounds 17-24 with MDM2 protein
(PDB ID: 4ODE)
Glide
evdw
Glide
ecoul
XP
Interacting
Residues
Entry
Comp.
GScore
1
2
3
17
18
19
-8.046
-7.238
-7.88
-39.835
-42.618
-19.387
2.373
-3.552
5.124
H2O 326
GLN 59, H2O 312
HIE 96, H2O 312
HIE 96, MET 6,
H2O 312 & H2O
338
5
. The screening results revealed that the tested compounds
exhibited good and moderate antitumor activity against Hep
G2 cell line. Among this series, compounds 17 and 19 showed
significant activity in the tested cells (Fig. 7) with IC50 values
33.05±0.95 and 49.82±0.61 μM for 24 h and 22.03±1.61 and
28.58±2.53 μM for 48 h respectively. It was observed that the
4
20
-7.531
-46.244
-5.198
5
6
7
8
21
22
23
24
-7.48
-7.057
-7.027
-8.427
-43.657
-38.596
-44.717
-35.388
0.881
1.12
H2O 326
H2O 338
N-CH3 piperidyl ring (compounds 17 and 19
important role in enhancing the cytotoxicity of these
compounds. The compounds 20 21 22 and 23 with chloro
) plays an
-1.989
-2.565
TYR 67
H2O 312
,
,
[Type text]
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3.4.2 Evaluation of Apoptosis (AO/EB Staining)
substitution pattern displayed moderate anticancer activity.
View Article Online
Hep G2 cells treated with IC50 doseDOoIf: 10t.h10e39s/Cyn5NthJe01s3iz6e9dK
compounds revealed apoptotic characteristics such as lose of
cytoplasmic membrane integrity there by uptake of ethidium
bromide making the nucleus stain red. Whereas the untreated
Hep G2 cells were stained green as a result of intercalation
into the double stranded DNA.
Whereas the remaining compounds 18 and 24 showed
Fig. 6 Morphological observations of Hep G2 cells by inverted
microscope at actual magnification 40X. A) Untreated control cells
B) Hep G2 cell line showing nuclear fragmentation upon treatment
with compounds 17-24 after 24 h, C) After 48 h.
lower anticancer potency as compared to other compounds.
These aspects show that the methyl substitution (N-CH3) in the
piperidyl ring is important to enhance the anticancer activity.
Fig. 8 Analysis of apoptotic characters of compounds 17-24 by
AO/EB staining in liver carcinoma human cell line Hep G2 in
fluorescence microscopy at 40X magnification.
Early apoptotic cells showed bright green nucleus with
condensed or fragmented chromatin and late apoptotic cells
display condensed and fragmented orange or red colored
chromatin. Cells that have died from direct necrosis have a
structurally normal orange nucleus. Analysis of apoptotic
characters by AO/EB staining in Hep G2 cell line treated with
newly synthesized compounds (17-24) using fluorescence
microscopy is shown in Fig. 8. The treatment of compounds 17
and 19 caused more cells to undergo death in Hep G2 liver
cancer cells, in agreement with the cytotoxic results. The
observations revealed that all the compounds treated cells
show cytological changes, whereas in the untreated cells, no
such changes were observed. The photomicrographs in Fig. 8
show viable (light green), early apoptotic (bright green), late
apoptosis (red to orange) and necrosis (red) cells.
Fig. 7 IC50 range of Compounds 17-24 against Hep G2 human liver
cancer cells. Data shown are the mean values from six independent
experiments.
Table 5. IC50 values (expressed in μM) of compounds 17-24 against
human liver cancer cell line Hep G2.
4. Conclusions
In conclusion, a convenient and efficient method to synthesize
thiazin–4–one derivatives with good yields has been reported.
The newly synthesized compounds were characterized by FT–
IR, HR–Mass and 1D/2D NMR. All the spectral data
unambiguously demonstrates the cyclization of DMAD or
IC50 (μM)
Entry
Comp.
24h
48h
1
2
3
4
5
6
7
8
17
18
19
20
21
22
23
24
33.05 ± 0.95
77.63 ± 0.76
49.82 ± 0.61
57.26 ± 1.32
51.03 ± 3.31
63.58 ± 0.57
58.29 ± 0.79
70.52 ± 3.22
22.03 ± 1.61
61.80 ± 3.17
28.58 ± 2.53
44.57 ± 1.90
45.32 ± 0.47
56.32 ± 1.67
44.82 ± 2.84
42.87 ± 2.27
DEAD
with
3–alkyl–2,6–diarylpiperdin–4–one
thiosemicarbazone derivatives resulting in six–membered
thiazin–4–one regioselectively. From the chemical shifts and
coupling constants, the title compounds were found to adopt
chair conformations with equatorial orientation of aryl groups.
The representative compound (17) was theoretically studied
using DFT at B3LYP and M06 level of theories and found to be
in good agreement with the structure elucidated by 2D NMR
8 | J. Name., 2012, 00, 1-3
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17 A. A. Esmaeili, A. Moradi and H. K. Mohammadi,
DOI: 10.1039/C5NJ01369K
18 V. Nair, A. Deepthi, M. Poonoth, B. Santhamma, S. Vellalath,
spectra. The interactions between the synthesized compounds
and the tumor protein MDM2 were studied by molecular
docking. The docking results indicate that the compounds 19
and 20 show interactions with the critical amino acid HIE 96
which is necessary for the inhibition of MDM2 protein. The
View Article Online
Tetrahedron, 2010, 66, 3575–3578.
B. P. Babu, R. Mohan and E. Suresh, J. Org. Chem., 2006, 71
,
2313–2319.
19 M. Fan, Z. Yan, W. Liu and Y. Liang, J. Org. Chem., 2005, 70
8204–8207.
,
drug−like properties predictions show that the compounds 17
,
20 M. G. Bhovi and G. S. Gadaginamath, Indian J. Chem., 2005,
44B, 1068–1073.
19 and 24 have no violations owing to the Lipinski’s rule of five
and other tested parameters. Furthermore, in the evaluation
of antitumor studies, compounds 17 and 19 with N-CH3
substitution in the piperidyl ring showed good inhibitory
activity against Hep G2 human liver cancer cell line. These
compounds were also identified as a best molecules in
drug−like properties prediction. The evaluation of apoptosis
using AO/EB staining shows changes in the nuclear
morphology by the formation of apoptotic bodies and these
cell death also in agreement with the cytotoxicity results.
21 Maestro, version 9.3.5, Schrödinger, LLC, New York, 2012.
22 Y. Rew, D. Sun, F. G. D. Turiso, M. D. Barberger, H. P. Beck, J.
Canon, A. Chen, D. Chow, J. Diegnan, B. M. Fox, D. Gustin, X.
Huang, M. Jlang, X. Jiao, L. Jin, F. Kayser, D. J. Kopecky, Y. Li,
M. Lo, A. M. Long, K. Michelsen, J. D. Oliner, T. Osgood, M.
Ragains, A. Y. Saiki, S. Schneider, M. Toteva, P. Yakowec, X.
Yan, Q. Ye, D. Yu, X. Zhao, J. Zhou, J. C. Medina and S. H.
Olson, J. Med. Chem., 2012, 55, 4936-4954.
23 N. A. Danilkina, L. E. Mikhailov and B. A. Ivin, Russ. J. Org.
Chem., 2006, 42, 783-814.
24 I. Yavari, M. Sabbaghan, K. Porshamsian, M. Bagheri, S. A.
Asgari and Z. Hossaini, Mol. Divers, 2007, 11, 81–85.
25 V. S. Berseneva, A. V. Tkachev, Y. Y. Morzherin, W. Dehaen, I.
Luyten, S. Toppet and V. A. Bakulev, J. Chem. Soc. Perkin
Trans., 1998, 1, 2133–2136.
Acknowledgements
We gratefully acknowledge the funding support from
University Grants Commission (UGC) Grant No. 39–689–2010
SR and Department of Biotechnology (DBT) Grant No.
BT/PR14062/MED/30/357/2010, New Delhi, India. The
26 G. N. Lipunova, E. V. Nosova, A. A. Laeva, T. V. Trashakhova,
P. A. Slepukhin and V. N. Charushin, Russ. J. Org. Chem.,
2008, 44, 741–749.
27 J. J. Wade, J. Org. Chem., 1979, 44, 1816–1819.
computations have been supported by Department of 28 V. A. Bakulev, V. S. Berseneva, N. P. Belskaia, Y. Y. Morzherin,
A. Zaitsev, W. Dehaen, I. Luyten and S. Toppet, Org. Biomol.
Chem., 2003, 1, 134–139.
Biotechnology–North East Collaboration (DBT–NEC) Research
Project, Grant No. BT/252/NE/TBP/2011, New Delhi, India.
29 (a)V. P. M. Rahman, S. Mukhtar, W.H. Ansari and G. Lemiere,
Eur. J. Med. Chem., 2005, 40, 173–184;
(b) D. Havrylyuk, B. Zimenkovsky, O. Vasylenko, C.W. Day, D.
F Smee, P. Grellier and R. Lesyk, Eur. J. Med. Chem., 2013, 66,
228–237;
(c) H. Zhou, S. Wu, S. Zhai, A. Liu, Y. Sun, R. Li, Y. Zhang, S.
Ekins, P. W. Swaan, B. Fang, B. Zhang and B. Yan, J. Med.
Chem., 2008, 51, 1242–1251.
References
1
2
A. M. Clark, Pharm. Res., 1996, 13, 1133–1141.
C. J. Sutherland, J. E. Montgomery and I. G. Kestin, Paediatr
Anaesth., 1998, 8, 321–324.
3
4
F. H. Shaw and A. Shulman, Nature, 1955, 175, 388–389.
P. G. Lawlor, K. S. Turner, J. Hanson and E. D. Bruera, Cancer,
1998, 82, 1167–1173.
M. Koch, K. Perumal, O. Blacque, J. A. Garg, R. Saiganesh, S.
Kabilan, K. K. Balasubramanian and K. Venkatesan, Angew.
Chem., 2014, 126, 6496-6500.
30 (a) K. Mogilaiah, P. R. Reddy and R. B. Rao, Indian J. Chem.,
1999, 38B, 495–500;
(b) D. Patel, P. Kumari and N. Patel, Eur. J. Med. Chem., 2012,
48, 354–362.
31 (a) H. Yamashita, K. Ohno, H. Inami, J. Shishikura, S.
Sakamoto, M. Okada and T. Yamaguchi, Eur. J. Pharmacol.,
2004, 494, 147–154;
(b) C. Dwivedi, T. K. Gupta and S. S. Parmar, J. Med. Chem.,
1972, 15, 553–554.
32 (a) B. A. Sobin, J. Am. Chem. Soc., 1952, 74, 2947–2948;
(b) A. S. Narute, P. B. Khedekar and K. P. Bhusari, Indian J.
Chem., 2008, 47B, 586–591.
33 M. L. Barreca, J. Balzarini, A. Chimirri, E. D. Clercq, L. D. Luca,
H. D. Holtje, M. Holtje, A. M. Monforte, P. Monforte, C.
Pannecouque, A. Rao and M. Zappalà, J. Med. Chem., 2002,
45, 5410–5413.
34 K. Ohno, R. Tsutsumi, N. Matsumoto, H. Yamashita, Y.
Amada, J. Shishikura, H. I. S. Yatsugi, M. Okada, S. Sakamoto
and T. Yamaguchi, J. Pharmacol. Exp. Ther., 2003, 306, 66–
72.
5
6
7
8
K. Narayanan, M. Shanmugam, G. Vasuki and S. Kabilan, J.
Mol. Struct., 2014, 1056–1057, 70–78.
S. Umamatheswari, B. Balaji, M. Ramanathan and S. Kabilan,
Eur. J. Med. Chem., 2011, 46, 1415–1424.
P. Karthikeyan, A. Meena Rani, R. Saiganesh, K.K.
Balasubramanian and S. Kabilan, Tetrahedron, 2009 65, 811–
821.
K. Narayanan, M. Shanmugam, S. Jothivel and S. Kabilan,
Bioorg. Med. Chem. Lett., 2012, 22, 6602–6607.
9
10 S. Umamatheswari, B. Balaji, M. Ramanathan and S. Kabilan,
Bioorg. Med. Chem. Lett., 2010, 20, 6909–6914.
11 R. Ramachandran, M. Rani, S. Senthan, Y. T. Jeong and S.
Kabilan. Eur. J. Med. Chem., 2011, 46, 1926–1934.
12 S. Balasubramanian, C. Ramalingan, G. Aridoss and S.
Kabilan, Eur. J. Med. Chem., 2005, 40, 694–700.
13 G. Aridoss, P. Parthiban, R. Ramachandran, M. Prakash, Y. T.
Jeong and S. Kabilan, Eur. J. Med. Chem., 2009, 44, 577– 592.
14 G. Aridoss, S. Balasubramanian, P. Parthiban and S. Kabilan,
Eur. J. Med. Chem., 2007, 42, 851–860.
15 S. Balasubramanian, G. Aridoss, P. Parthiban, C. Ramalingan
and S. Kabilan, Biol. Pharm. Bull., 2006, 29, 125–130.
16 G. C. Nandi, S. Samai and M. S. Singh, J. Org. Chem., 2011,
76, 8009–8014.
35 C. J. Andres, J. J. Bronson, S. V. D’Andrea, M. S. Deshpande,
P. J. Falk, K. A. Grant–Young, W. E. Harte, H. Ho, P. F. Misco,
J. G. Robertson, D. Stock, Y. Sun and A. W. Walsh, Bioorg.
Med. Chem. Lett., 2000, 10, 715–717.
36 C. R. Noller and V. Baliah, J. Am. Chem. Soc., 1948, 70, 3853–
3855.
37 V. Baliah, R. Jeyaraman and L. Chandrasekaran, Chem. Rev.,
1983, 83, 379–423.
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38 S. Balasubramanian, C. Ramalingam and S. Kabilan, Indian J.
Chem., 2002, 41B, 2402–2404.
View Article Online
DOI: 10.1039/C5NJ01369K
39 Jaguar, version 7.9, Schrödinger, LLC, New York, 2012.
40 Qikprop, version 3.5, Schrödinger, LLC, New York, 2012.
41 (a) C. A. Lipinski, F. Lombardo, B. W. Dominy and P. J.
Feeney, Adv. Drug Deliv. Rev., 1997, 23, 3–25;
(b) C. A. Lipinski, F. Lombardo, B. W. Dominy and P. J.
Feeney, Adv. Drug Deliv. Rev., 2001, 46, 3–26.
42 (a) P. Chene, Nat. Rev. Cancer, 2003,
3
, 102-109.
(b) K. Khoury, G. M. Popowicz, T. A. Holak and A. Domling,
Med. Chem. Commun., 2011,
2, 246-260.
43 D. Bernard, Y. Zhao and S. Wang, J. Med. Chem., 2012, 55
,
4934-4935.
44 A. Z. Gonzalez, Z. Li, H. P. Beck, J. Canon, A. Chen, D. Chow, J.
Duquette, J. Eksterowicz, B. M. Fox, J. Fu, X. Huang, J. Houze,
L. Jin, Y. Li, Y. Ling, M. Lo, A. M. Long, L. R. McGee, J.
McIntosh, J. D. Oliner, T. Osgood, Y. Rew, A. Y. Saiki, P. Shaer,
S. Wortman, P. Yakowec, X. Yan, Q. Ye, D. Yu, X. Zhao, J.
Zhou, S. H. Olson, D. Sun and J. C. Medina, J. Med. Chem.,
2014, 57, 2963-2988.
45 Protein Preparation Wizard; Epik version 2.3, 2012; Impact
version 5.7, 2012, Schrödinger, LLC, New York.
46 W. L. Jorgensen, D. S. Maxwell and J. Tirado–Rives, J. Am.
Chem. Soc., 1996, 118, 11225–11236.
47 LigPrep, version 2.5, 2012, Schrödinger, LLC, New York.
48 Glide, version 5.8, 2012, Schrödinger, LLC, New York.
49 T. Mosmann, J. Immunol. Methods, 1983, 65, 55–63.
50 D. L. Spector, R. D. Goldman and L. A. Leinwand, Culture and
biochemical Analysis of cells, In: Cell: A Laboratory Manual,
1998, 1, Cold Spring Harbor Laboratory Press, Cold Spring
Harbor, New York.
51 N. A. Danilkina, L. E. Mikhaylov and B. A. Ivin, Chem.
Heterocycl. Compd., 2011, 47, 886−900.
52 B. Fabian, V. Kudar, A. Csampai, T. Z. Nagy and P. Sohar, J.
Organomet. Chem., 2007, 692, 5621−5632.
53 N. Nami, M. Hosseinzadeh and E. Rahimi, Phosphorus, Sulfur,
and Silicon, 2008, 183, 2438−2442.
54 V. N. Britsun and M. O. Lozinskii, Chem. Heterocycl. Compd.,
2007, 43, 1083−1100.
55 R. M. Acheson and J. D. Wallis, J. Chem. Soc. Perkin Trans. I,
1981, 415−422
56 (a) F. Gonzalez-Lopez de Turiso, D. Sun, Y. Rew, M. D.
Bartberger, H. P. Beck, J. Canon, A. Chen, D. Chow, T. L.
Correll, X. Huang, L. D. Julian, F. Kayser, M. C. Lo, A. M. Long,
D. McMinn, J. D. Oliner, T. Osgood, J. P. Powers, A. Y. Saiki, S.
Schneider, P. Shaffer, S. H. Xiao, P. Yakowek, X. Yan, Q. Ye, D.
Yu, X. Zhao, J. Zhou, J. C. Medina and S. H. Olson, J. Med.
Chem., 2013, 56, 4053−4070.
(b) D. Bernard, Y. Zhao and S. Wang, J. Med. Chem., 2012, 55
4934−4935.
,
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