Synthesis, bioactivities, DFT and in-silico appraisal of azo clubbed benzothiazole derivatives

Article abstract of DOI:10.1016/j.molstruc.2019.04.123

Six new azo clubbed benzothiazole dyes were synthesized by diazotization reaction. These six novel compounds were characterized using ¹H NMR, FTIR, UV–Visible, fluorescence spectroscopy, LC-MS, and elemental analysis. The in-vitro antimicrobial

Full text of DOI:10.1016/j.molstruc.2019.04.123

Accepted Manuscript
Synthesis, bioactivities, DFT and in-silico appraisal of azo clubbed benzothiazole
derivatives
Chaitannya W. Ghanavatkar, Virendra R. Mishra, Suraj N. Mali, Hemchandra K.
Chaudhari, Nagaiyan Sekar
PII:
S0022-2860(19)30534-4
DOI:
https://doi.org/10.1016/j.molstruc.2019.04.123
MOLSTR 26495
Reference:
To appear in: Journal of Molecular Structure
Received Date: 30 January 2019
Revised Date: 3 April 2019
Accepted Date: 28 April 2019
Please cite this article as: C.W. Ghanavatkar, V.R. Mishra, S.N. Mali, H.K. Chaudhari, N. Sekar,
Synthesis, bioactivities, DFT and in-silico appraisal of azo clubbed benzothiazole derivatives, Journal of
Molecular Structure (2019), doi: https://doi.org/10.1016/j.molstruc.2019.04.123.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Synthesis, Bioactivities, DFT and in-silico appraisal of azo clubbed
Benzothiazole derivatives.
a
b
Chaitannya W. Ghanavatkar , Virendra R. Mishra, Suraj N. Mali , Hemchandra K.
b
a,*
Chaudhari , Nagaiyan Sekar
Chaitannya W. Ghanavatkar -ORCID ID- https://orcid.org/0000-0003-0821-1083
Virendra R. Mishra -ORCID ID- https://orcid.org/0000-0003-0070-4705
a,*
Department of Dyestuff Technology, Institute of Chemical Technology, Matunga (E),
Mumbai, Maharashtra, India, PIN: 400 019.
E-mail: nethi.sekar@gmail.com; n.sekar@ictmumbai.edu.in
ORCID ID- https://orcid.org/0000-0001-7568-5129
Suraj Narayan Mali -ORCID ID- https://orcid.org/0000-0003-1995-136X
b
Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology,
Matunga (E), Mumbai, Maharashtra, India, PIN: 400 019.
E-mail: hemchandrachaudhari@yahoo.com, hk.chaudhari@ictmumbai.edu.in
ORCID ID- https://orcid.org/0000-0001-6866-9147

ACCEPTED MANUSCRIPT
Graphical Abstract:
Abstract
Six new azo clubbed benzothiazole dyes were synthesized by diazotization reaction. These
1
six novel compounds were characterized using H NMR, FTIR, UV–Visible, fluorescence
spectroscopy, LC-MS, and elemental analysis. The in-vitro antimicrobial screening studies
were performed using popular REMA assay method on “gram-positive” (“Staphylococcus
aureus”) and “gram-negative” (“Escherichia coli”) strains. DNA cleavage study was also
carried out to check nuclease activity. The “HOMO-LUMO” theoretical calculations were
correlated with current in-vitro antibacterial results. In -silico studies were performed using
Molecular Docking, Molecular dynamics, Prime MMGBSA, admetSAR, and QikProp
ADMET method.
Keywords: Benzothiazole, azo clubbed heterocycles, biological activity, Molecular docking,
Density functional theory (DFT)

ACCEPTED MANUSCRIPT
1
. Introduction
Since the last couple of decades, S and N containing heterocycles i.e. Benzothiazole,
thiazole, isothiazole scaffolds attracted researchers and utilized in dyeing on polyester
fiber[1,2], nonlinear optical materials (NLO) [3], structural and spectroscopic properties,
ESIPT and DFT studies[4,5], antimycobacterial [6], antimicrobial [7], anticancer [8] and
various pharmacological activities[9]. Furthermore, pyridone and pyrazole containing
compounds also play an important role in medicinal chemistry [10–15].
Among these compounds, Heterocyclic azo dyes can be easily produced and comprise
an important class of aromatic compounds[1,16–20]. Azo dyes are also involved in biological
reactions like RNA inhibition, nitrogen fixation, protein synthesis [21]. Various azo dyes
containing either metal complex or heterocyclic ring are synthesized and tested for in vivo
and in vitro activity[22–24]. An azo compound Sulfasalazine is a well-known antibiotic in
human infections have great importance, as sulfonamides are derived from “protonsil”.
However, Antimicrobial drug resistance to antibiotics is a widespread problem. Hence
design, synthesis, and testing of new compounds are necessary.
In this regard, we designed, synthesized and screened the biological activity of six
new benzothiazole containing heterocyclic azo dyes. Dyes are synthesized through azo
coupling reaction using substituted pyridone or substituted pyrazole as coupling component.
The newly synthesized heterocyclic azo dyes are investigated for their potential in-vitro
activities against both, “gram-positive” i.e. “S. aureus” (“Staphylococcus aureus”) and
“gram-negative” bacteria i.e. “E. Coli” (“Escherichia Coli”) strains by using “REMA
method”. DNA cleavage activity studies were carried out using the electrophoretic mobility
shift assay. “HOMO-LUMO” gap of all the compounds were calculated using the
computational method and used to compare with the actual in-vitro antibacterial results.
The molecular docking simulations were performed for three bacterial targets including the
common one. Using Molecular docking study, the binding affinities were determined [25]
against the variety of targets and might reveal more insights into the possible mechanisms.
2
2
. Experimental
.1 Materials and equipment
Solvents and chemicals were obtained from the commercial source (“Spectrochem” and “SD
Fine Chemicals Ltd”.) and then used for the experiments with no further purification.
Reactions were monitored by using thin layered chromatography plates (TLC) (0.25mm “E-

ACCEPTED MANUSCRIPT
Merck silica gel 60-F254, pre-coated”). TLC plates were visualized using UV light. Standard
melting point apparatus used from “Sunder industrial product, Mumbai” to analyze melting
1
points. “Nuclear magnetic resonance ( H NMR)” spectra recorded using 400MHz or 500MHz
instrument of “Agilent Technology”. “FT-IR” spectrum recorded on “Perkin Elmer Fourier
Transform IR instrument”. “Perkin Elmer Lambda-25 spectrophotometer” was used to record
o
the absorption spectra of all the compounds at room temperature (25-27 C). Fluorescence
spectra are recorded with “Varian Cary Eclipse fluorescence spectrophotometer” at room
temperature. The LC-MS of the compounds were measured on Varian Inc. mass analyzer (410
Prostar Binary LC with 500 MS IT model) with Electrospray Ionization (ESI, negative mode).
2
.2 Computational Method
“Density Functional Theory (DFT)” was used to optimize the ground state of all compounds
by using the “Gaussian 09 package” [26] and popular “hybrid functional B3LYP”. The
B3LYP functional is a combination of “Becke’s three parameter exchange functional (B3)”
[
27] with the “nonlocal correlation functional of Lee, Yang, and Parr (LYP)” [28]. The basis
sets used for all atoms were the popular Pople’s split-valence basis sets. The B3LYP
functional is used with the “double zeta basis set 6-31G (d)” for optimization. Molecules are
optimized in the gas phase using the same basis sets.
2
.3 Molecular Modelling
The popular Glide module from Schrodinger’s molecular modeling package was utilized for
calculations of molecular dockings. Molecular dynamics for 1.2ns was done using Desmond
module incorporated in Schrodinger's molecular modeling package 2017 [29]. All properties
corresponding with calculations of ADME were calculated using the QikProp [30] module
(QikProp, Schrodinger LLC, NY, 2017). The molecular mechanics generalized born surface
area energies (MM GBSA) were also calculated using the Prime module [31].
2
2
.4 Biological activities
.4.1 Antibacterial activities
The newly synthesized azo compounds were checked for their antimicrobial activity by using
the “REMA” (“Resazurin microtiter assay method”) on “gram-positive”, “S. aureus”
(“Staphylococcus aureus”) and “gram-negative”, “E. Coli” (“Escherichia coli”) bacterial
strains. The activities are reported in “Minimum inhibitory concentration (MIC in µg/mL)”
form. Detail procedure is given in Supplementary Information (SI).
2
.4.2 DNA cleavage studies

ACCEPTED MANUSCRIPT
DNA cleavage studies carried out with the plasmid pBR 322 DNA using the Electrophoretic
mobility shift assay. Detail procedure is given in Supplementary Information (SI).
2
.5 Synthesis
Intermediates (3, 7) [32] and (C1, C2) [33] were synthesized as reported. (C3) used as it is
received from a commercial source.
2
.5.1 General procedure for preparation of intermediates 4 and 8
Substituted aromatic amine- 3 or 7 (2 mmol.) was stirred in 30% or 70% H SO . The
2
4
o
obtained reaction mixture then cooled to 0-5 C. A solution of NaNO (2.2 mmol) prepared in
2
o
water and added dropwise over the period of 15 min at 0-5 C. The resulting reaction mixture
o
was stirred for 1.5 h at 0-5 C. Completion of diazotization was monitored by using starch-
iodide paper. 0.01 g of urea was added to consume an excess of nitrous acid. Resulting
diazonium salt solution was then immediately used for the coupling reaction with C1 or C2
or C3.
2
.5.2 General procedure for synthesis of heterocyclic azo dyes 5 (a-c) and 9 (a-c)
C1 or C2 or C3 (2 mmol.) dissolved in a stirred solution of NaOH (2 mmol.). A clear pale
o
yellow solution obtained is then cooled to 0-5 C. To this solution, diazotized amine was
o
added slowly, dropwise with mechanical stirring by maintaining temperature at 0-5 C.
Saturated sodium carbonate solution was added simultaneously to maintain pH of reaction
mixture at 7–9. The solution was stirred for 2 h., before diluting or raising to neutral pH. The
resulting dyes 5(a-c) and 9(a-c) are then filtered, washed with water, and recrystallized using
ethanol. Scheme A represents the synthesis of new azo dyes.
2
.5.2.1 Synthesis of 5-((3-(Benzo[d]thiazol-2-yl)-4-hydroxyphenyl)diazenyl)-1-butyl-6-
hydroxy-4-methyl-2-oxo-1,2-dihydropyridine-3-carbonitrile
(5a).
Brown-Red
-1
1
solid.Yield:85 %, m.p.=310-312 °C IR (ʋ cm ) 3270 (OH), 2227 (CN), 1512(-N=N-) H
6
NMR (500 MHz, DMSO-d ) δ 14.76 (s, 1H), 11.93 (s, 1H), 8.45 (d, J = 2.2 Hz, 1H), 8.12 (d,
J = 7.9 Hz, 1H), 8.04 (d, J = 8.1 Hz, 1H), 7.74 (d, J = 9.0 Hz, 1H), 7.54 (t, J = 7.3 Hz, 1H),
7
.44 (t, J = 7.6 Hz, 1H), 7.14 (d, J = 8.9 Hz, 1H), 3.80 – 3.75 (m, 2H), 2.48 (s, 3H), 1.51 (m,
J = 14.7, 7.4 Hz, 2H), 1.29 (m, J = 14.8, 7.4 Hz, 2H), 0.89 (t, J = 7.4 Hz, 3H). LC–MS: m/z
-
=
458.1, [M–H] . Elemental analysis Anal. Calcd for C H N O S C, 62.73; H, 4.61; N,
2
4
21
5
3
1
2
4
8
5.24; found C, 62.76; H, 4.61; N, 15.25
.5.2.2 Synthesis of 5-((3-(Benzo[d]thiazol-2-yl)-4-hydroxyphenyl) diazenyl)-6-hydroxy-
-methyl-2-oxo-1-phenyl-1,2-dihydropyridine-3-carbonitrile (5b). Brown solid, Yield:
-1
1
3%, m.p.= 298-300 °C, IR (ʋ cm ) 3573(OH), 2219 (CN), 1508(-N=N-) H NMR (400

ACCEPTED MANUSCRIPT
6
MHz, DMSO-d ) δ 14.62 (s, 1H), 11.94 (s, 1H), 8.43 (s, 1H), 8.11 (d, J = 7.6 Hz, 1H), 8.00
(d, J = 7.6 Hz, 1H), 7.71 (d, J = 5.9 Hz, 1H), 7.56 – 7.34 (m, 5H), 7.27 (d, J = 7.2 Hz, 2H),
-
7
.13 (d, J = 8.9 Hz, 1H), 2.47 (s, 3H). LC–MS: m/z =478.0, [M–H]
.
Elemental analysis
Anal. Calcd for C H N O S C, 65.12; H, 3.57; N, 14.61 found C, 65.15; H, 3.57; N, 14.62
2
6
17
5
3
2
.5.2.3 Synthesis of 4-((3-(Benzo[d]thiazol-2-yl)-4-hydroxyphenyl)diazenyl)-3-methyl-1-
-1
phenyl-1H-pyrazol-5-ol (5c). Brown solid. Yield: 82%, m.p. = 226-228°C, IR (ʋ cm )
1
6
3
594(OH), 3064 (Ar-CH), 1547 (-N=N-) H NMR (400 MHz, DMSO-d ) δ 13.52 (s, 1H),
1.77 (s, 1H), 8.53 (s, 1H), 8.19 (d, J = 7.8 Hz,1H), 8.12 (d, J = 8.0 Hz, 1H), 7.96 (d, J = 8.0
1
Hz, 2H), 7.75 (d, J = 8.6 Hz, 1H), 7.58 (t, 1H), 7.48 (t, J = 7.5 Hz, 3H), 7.30 – 7.15 (m, J =
-
1
4.9, 8.0 Hz, 2H), 2.36 (s, 3H). LC–MS: m/z =426.0, [M–H] . Elemental analysis Anal.
Calcd. for C H N O S: C, 64.62; H, 4.01; N, 16.38; found C, 64.67; H, 4.01; N, 16.38
2
3
17
5
2
2
.5.2.4 Synthesis of 5-((4-(Benzo[d]thiazol-2-yl)-3-hydroxyphenyl)diazenyl)-1-butyl-6-
hydroxy-4-methyl-2-oxo-1,2-dihydropyridine-3-carbonitrile (9a). Red-orange solid,
-1
1
Yield: 87% m. p.=300-302°C, IR (ʋ cm ) 3578 (OH), 2226 (CN), 1506 (-N=N-) H NMR
6
(
400 MHz, DMSO-d ) δ 14.42 (s, 1H), 11.94 (s, 1H), 8.23 (d, J = 8.7 Hz, 1H), 8.10 (d, J =
7
.8 Hz, 1H), 8.01 (d, J = 8.1 Hz, 1H), 7.54 – 7.47 (m, 1H), 7.45 – 7.38 (m, 1H), 7.37 – 7.28
(m, J = 13.6, 7.1 Hz, 2H), 3.80 (t, 2H), 2.51 (s, 3H), 1.56 – 1.45 (m, 2H), 1.34 – 1.23 (m,
-
2
H), 0.88 (t, 3H). LC–MS: m/z =458.2, [M–H] . Elemental analysis Anal. Calcd. for
C H N O S C, 62.73; H, 4.61; N, 15.24; found: C, 62.78; H, 4.66; N, 15.25
24
21
5
3
2
4
.5.2.5 Synthesis of 5-((4-(Benzo[d]thiazol-2-yl)-3-hydroxyphenyl)diazenyl)-6-hydroxy-
-methyl-2-oxo-1-phenyl-1,2-dihydropyridine-3-carbonitrile (9b). Red solid, Yield: 91%
-1
1
m. p. = 286-287°C, IR (ʋ cm ) 3565 (OH), 3071 (Ar-CH), 2225 (CN), 1513(-N=N-), H
6
NMR (400 MHz, DMSO-d ) δ 14.17 (s, 1H), 11.81 (s, 1H), 8.10 (d, J = 8.6 Hz, 1H), 7.97 (d,
J = 7.8 Hz, 1H), 7.88 (d, J = 8.1 Hz, 1H), 7.37 (s, 1H), 7.36 (d, J = 1.9 Hz, 1H), 7.34 (s, 1H),
7
.33 – 7.31 (m, 1H), 7.30 (d, J = 3.4 Hz, 1H), 7.24 (d, J = 1.9 Hz, 1H), 7.21 (d, J = 2.2 Hz,
1
H), 7.17 (d, J = 1.5 Hz, 1H), 7.16 (d, J = 1.7 Hz, 1H), 2.48 (s, 3H). LC–MS: m/z =478.0,
-
[
M–H] . Elemental analysis Anal. Calcd for C H N O S C, 65.12; H, 3.57; N, 14.61 found:
2
6
17
5
3
C, 65.15; H, 3.57; N, 14.62
2
.5.2.6 Synthesis of 4-((4-(Bsenzo[d]thiazol-2-yl)-3-hydroxyphenyl)diazenyl)-3-methyl-1-
-1
phenyl-1H-pyrazol-5-ol (9c). Brown solid. Yield:85% m. p. =215-217 °C, IR (ʋ cm )
1
6
3
1
7
7
569(OH), 3064 (Ar-CH), 1540(-N=N-) H NMR (400 MHz, DMSO-d ) δ 13.27 (s, 1H),
1.94 (s, 1H), 8.28 (d, J = 8.7 Hz, 1H), 8.15 (d, J = 8.0 Hz, 1H), 8.06 (d, J = 8.0 Hz, 1H),
.94 (d, J = 7.9 Hz, 1H), 7.58 – 7.53 (m, 1H), 7.52 – 7.43 (m, 3H), 7.34 (d, J = 1.8 Hz, 1H),
.31 (d, J = 2.0 Hz, 1H), 7.29 (d, J = 2.1 Hz, 1H), 7.25 (t, 1H), 2.35 (s, 3H). LC–MS: m/z

ACCEPTED MANUSCRIPT
-
=
426.0, [M–H] . Elemental analysis Anal. Cald. for C H N O S C, 64.62; H, 4.01; N,
23 17 5 2
1
6.38; found C, 64.64; H, 4.01; N, 16.39
Scheme A: Synthesis scheme of new Heterocyclic Azo Dyes 5 (a-c) and 9 (a-c).
3
. Results and discussions
Six new heterocyclic azo dyes containing benzothiazole moiety are successfully synthesized
according to scheme A. Intermediates 3 and 7 are prepared via cyclisation, by reacting of 5-
aminosalicylic acid or 4-aminosalicylic acid with 2-aminothiophenol respectively. These
o
intermediates 3 or 7 were treated with conc. H SO and sodium nitrite (NaNO ) at 0-5 C to
2
4
2
obtain the diazonium salt solution and then coupled with compounds C1 or C2 or C3 at 0-5
o
C by maintaining pH 7-9. The desired new heterocyclic dyes 5(a-c) and 9(a-c) were
obtained in good yield.

ACCEPTED MANUSCRIPT
3
3
3
.1 Characterization
-
1
.1.1 In the “IR spectra” of 5(a-c) and 9(a-c), a broad peak observed around 3270 cm to
-1
-1
600 cm and assigned for (-OH) stretching . Peaks observed between 1500-1550 cm are
due to azo group, (-N=N-) stretching vibrations. The “aromatic C–H stretching” vibrations
−
1
were observed between 3060–3170 cm .
1
6
3
.1.2 H NMR spectra, of 5(a-c) and 9(a-c) are analyzed in DMSO (d ). Multiplet peaks in
the range of 7.14-8.45 ppm shown the presence of aromatic ring protons. In all the dyes, 5(a-
c) and 9(a-c), two singlets peaks in the 11-14 ppm region, are due to presence of hydroxyl
proton. For 5a and 9a, peaks are observed in the 0.9-2.7 ppm region, shows the presence of
aliphatic protons. Singlet peak for three protons observed around 2.30 ppm to 2.50 ppm
confirms presence of (Ar-CH3)
3
.1.3 UV-Visible and fluorescence study
A “UV-visible spectra” of 5(a-c) or 9(a-c) was measured in ethyl acetate as a solvent at a
concentration of 10 µM in the wavelength range of 350-700 nm. The λmax range for reported
azo compounds is 414-457 nm. Emission spectra also measured in ethyl acetate solvent. All
the azo compounds are emissive in the wavelength range of 495-561 nm and stoke’s shift in
the range of 79-105 nm. Pyrazole containing compounds (5c and 9c) are less emissive than
Pyridone compounds (5a, 5b, 9a, 9b). All the data is summarized in Table 1.
Table 1: Absorption and emission spectral data for 5(a-c) and 9(a-c)
Compound
Absorbance
nm)
Emission
(cm )
Stoke's shift
-
1
-1
-1
(
(cm )
21930
21881
24155
21882
21930
23753
(nm)
559
551
495
560
561
500
(nm)
103
94
(cm )
4041
3733
3953
4025
4105
3753
5
a
456
457
414
457
456
421
17889
18148
20202
17857
17825
20000
5
b
5
9
c
a
81
103
105
79
9
b
9
c

ACCEPTED MANUSCRIPT
Figure.1 UV-Visible absorption and emission spectra of synthesized 5(a-c) and 9(a-c) in
Ethyl Acetate
3
3
.2 Biological evaluation
.2.1 Antibacterial testing
The six newly synthesized azo compounds, 5(a-c) and 9(a-c) were further tested for their
antimicrobial potential using the well-known “Resazurin microtiter assay method” (REMA)
method. All the activities are reported in “MIC(µg/mL)” and mentioned in Table 2. The
bacterial strains used were “gram-positive” (S. aureus) and “gram-negative” (“E. coli”)
bacteria. The standard “MIC values” obtained for ciprofloxacin drug were 50 µg/mL (on
S.aureus) and 25 µg/mL (on E.coli) [34]. The compounds 5a and 9c were obtained with
moderate antibacterial potential against “gram-negative” strains having “MIC values” of 312.5
µg/mL.
Table 2: The tabular representation for in-vitro antimicrobial activities of 5(a-c) and 9(a-c).
“
MIC” (µg/mL)
“
Gram- positive”
“Gram- negative”
Compound
(“Staphylococcus aureus”)
(“Escherichia coli”)
5
a
1250
1250
1250
625
312.5
1250
625
5
b
5
9
c
a
625
9
9
b
c
1250
625
50
625
312.5
25
Ciprofloxacin

ACCEPTED MANUSCRIPT
3
.2.2 Electrophoretic mobility shift assay (DNA cleavage studies)
The DNA cleavage studies carried out with the plasmid pBR 322 DNA using the
Electrophoretic mobility shift assay by using the well-known protocol [35]. An increment in
DNA isoforms was determined with naked eyes. When a circular plasmid DNA is run using the
agarose gel electrophoresis, the fastest migration will be for supercoiled form (SC) i.e. (Form
I). The slower moving open circular form (Form II) i.e. NC form will be produced, if one of
the strands cleaved. A linear form (Form III) will be observed if both strands cleave and it
will migrate in between SC form and NC form. Our results showed concentration-dependent
formation of NC (Form II) form from SC form (Form I) (SI, Figure S1). Presence of three
forms of pBR322 DNA for 9b and 9c proved that these compounds were slightly caused
double-strand DNA cleavage. There were distinguishable formations of condensed DNA forms and
majority formation of Nick DNA forms (Single-stranded DNA isoform upon cleavage). The slight
formation of “condensed DNA forms” may be attributed to the fact that, the compounds (with DNA
complex) are enough heavy to interact and cleave both the DNA strands so that they cannot migrate
across Gel- electrophoresis. Hence, observed at initial loading wells. So, we can say that
compounds are inhibiting bacterial growth due to DNA cleavage i.e. interaction with their
genome [36].

ACCEPTED MANUSCRIPT
Figure 2: The plot for antibacterial activities obtained for newly synthesized azo linked
compounds.
3
.3 “Molecular docking” and “ADME” predictions:
The flexible ligand docking simulations were carried out using the “Glide module” [28]. The
necessary 3D- crystal structure were obtained from the protein database. The crystal
structures used were dialkylglycine decarboxylase (PDB id-1D7U) [37,38], “S. aureus
Gyrase complex” with GSK299423 and DNA (PDB id:2XCS) [39] and “S. aureus Gyrase
complex” with ciprofloxacin and DNA(PDB id:2XCT) (Figures 3-5). The present six new
azo compounds along with standard drug ciprofloxacin were allowed to dock into active
pockets of these targets. The best dock compound, interacting residues, and their docking
scores are represented in Table 3 and 4. The molecular mechanics generalized born surface
area energy calculations were performed using the Prime module [30] (Table 3). The Prime
MMGBSA dG bind energy of 5c (-60.808 kcal/mol) was better than standard ciprofloxacin (-
3
5.625 kcal/mol). The moderate correlation between in-silico predictions and in-vitro activity data
may be attributed to the number of factors like type of cell walls, pH, cell membrane permeability,
environments, other metabolic reactions in bacteria, etc. which generally not considered during
docking simulations. The QikProp module was incorporated for calculations of ADME
parameters of these six new azo compounds (Table 5). The parameters calculated from
QikProp were found within acceptable ranges. The percent human oral absorption values

ACCEPTED MANUSCRIPT
predicted for all these new heterocycles were more than 80%. The low-high caco-cell
permeability and moderate-high logP values can be directly correlated with moderate antibacterial
potential. The loose correlation between MIC may be attributed to the moderate to high caco and logP
values. The changes in log P values (Lipophilicity parameter) can directly affect the passage of drug
through the cell membranes. The percent human oral absorption for Standard Ciprofloxacin was
found to be 48.861%; However for our compounds it is greater than standard. The in-silico
predictions for ciprofloxacin showed that all the parameters for ADME are moderate and it is non-
carcinogen. Accordingly, after comparing to standard ciprofloxacin, our compounds may be
effectively optimized into lead compounds for potent antimicrobials agents in future. The in-silico
carcinogenicity predictions and cytochrome profiling for compounds 5(a-c) and 9(a-c)
(Table 6) were done using the admetSAR tool [39]. Table 6 enlists the effect on various
metabolic enzymes i.e. cytochromes as calculated in-silico using the admetSAR.
Table 3: The scores obtained after for molecular docking of compounds 5(a-c) and 9(a-c) on
targets 2XCS, 2XCT and 1D7U.
Compound
PDB ID:2XCS
PDB ID:2XCT
PDB ID:1D7U
glide
Docking
glide
Docking
score
XP
glide
Docking
score
MMGBSA
dG Bind
Energy
score
XP
energy
energy
energy
XP
(
Kcal/mol)
(Kcal/mol)
(Kcal/mol)
-2.659
(Kcal/mol)
-43.162
5
5
a
-2.242
-38.61
-6.277
-38.92
-2.173
b
-4.048
-4.246
-41.289
-41.257
-5.955
-7.353
-36.093
-43.547
-2.711
-1.565
-8.74
-40.618
-60.808
5
c
-3.745
(most dock)
(most dock)
9
a
-2.593
-4.148
-4.423
-43.155
-33.476
-43.562
-4.519
-4.355
-6.486
-25.455
-38.018
-31.834
-3.008
-5.894
-40.31
9
b
-
-
-
-
-
-
9
c
(most dock)
Ciprofloxacin
-3.523
-41.993
-8.811
-41.855
-3.066
-12.357
-35.625
Table 4: The results for interactions obtained after molecular docking of compounds 5(a-c)
and 9(a-c) on target proteins 2XCS, 2XCT and 1D7U.
Compound
PDB ID:2XCS
PDB ID:2XCT
INTERACTING RESIDUES
MN G:2000(SALT
PDB ID:1D7U
5
a
DG E:10(PI-PI STACKING)
ARG406(PI-
BRIDGE)
CATION),LYS272(SALT
BRIDGE),TRP138(H-BOND)

ACCEPTED MANUSCRIPT
5
b
DC F:11,DG F:10,DC E:11,
MN G:2000(SALT
BRIDGE)
ARG406(PI-
CATION),LYS272(SALT
BRIDGE,PI-CATION)
DGE:10 (PI-PI
STACKING),GLY D:1117(H-
BOND)
5
c
DC F:11 & DG F:10(PI-PI
STACKING)
MN G:2000(SALT
BRIDGE),
DG G:9(PI-PI STACKING),
DA H:13(H-BOND)
ARG406 & LYS272(SALT
BRIDGE),GLN52(H-
BOND),TYR20(H-
BOND),TRP123(PI-PI
STACKING)
9
a
LYS D:581(H-BOND)
MN G:2000(SALT
BRIDGE), DG G:9,DA
H:13(PI-PI STACKING)
MN G:2000(SALT
ARG406(H-
BOND),TRP138(H-BOND)
9
b
DC E:11(PI-PI
STACKING,H-BOND), DC
F:11, DG E:10(PI-PI
STACKING)
NOT DOCKED
BRIDGE),
DA H:13(PI-PI
STACKING,H-BOND),DG
G:9(PI-PI STACKING)
MN G:2000(SALT
BRIDGE), DA H:13,DG
G:9(PI-PI STACKING)
MN G:2000(SALT
9
c
DC F:11,DG F:10, DG
E:10(PI-PI STACKING)
NOT DOCKED
CIPRO-
FLOXACIN
DG F:8,DG F:9(SALT
BRIDGE,H-BOND)
TRP138(PI-
CATION),ALA112(H-BOND)
BRIDGE), DA H:13,DG
G:9(PI-PI STACKING)
Figure 3: A] 2D and B] 3D interaction diagram for best dock 5c:1D7U.

ACCEPTED MANUSCRIPT
Figure 4: A] 2D and B] 3D interaction diagram for best dock 9c:2XCS.
Figure 5: A] 2D and B] 3D interaction diagram for best dock 5c:2XCT.

ACCEPTED MANUSCRIPT
Table 5: ADME predictions by QikProp of 5(a-c) and 9(a-c).
Compound
MW
volume QPlogPo/w QPPCaco #metab
%Human
Oral
PSA
Rule #stars
Of
Absorption
85.056
Five
5
a
459.52 1422.189
479.51 1430.656
427.48 1308.787
459.52 1425.501
479.51 1432.594
427.48 1306.605
3.523
3.803
5.085
3.569
3.831
5.08
124.247
125.057
853.876
131.696
131.327
880.024
13.583
5
5
5
5
5
5
0
124.696
125.646
87.057
0
0
1
0
0
1
0
1
2
2
1
2
2
1
5
b
86.746
96.224
85.781
87.292
96.435
48.861
5
9
c
a
124.577
125.473
86.984
9
b
9
c
Ciprofloxacin 331.346 1017.742
0.28
98.121
#
stars=Number of property or descriptor values that fall outside the 95% range of similar values for known
drugs ,QPlogPo/w = Predicted octanol/water partition coefficient, QPPCaco = Predicted apparent Caco-2 cell
permeability in nm/sec. , Percent Human Oral Absorption= Predicted human oral absorption on 0 to 100%
scale., Rule of Five= Number of violations of Lipinski’s rule of five, volume =Total solvent-accessible volume
in cubic angstroms using a probe with a 1.4 Å radius, PSA= Van der Waals surface area of polar nitrogen and
oxygen atoms, #metab=Number of likely metabolic reactions.
Table 6: In-silico distribution of 5(a-c) and 9(a-c) as obtained from the admetSAR server.
Compound
p-gp
substrate/
inhibitor
probabilit
y
CYP-2C9
substrate/
inhibitor
CYP-2D6
substrate/
inhibitor
CYP-3A4
substrate/
inhibitor
CYP-
1A2
inhibitor
CYP-
2C19
inhibitor
Rat Acute
Toxicity
LD50,
Carcinogenicity
mol/kg
5
5
a
Substrate
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Non-
Inhibitor
Non-
Inhibitor
2.4766
2.3636
Non-carcinogen
Non-carcinogen
/
Non
inhibitor
Non-
substrate
b
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Non-
Inhibitor
Inhibitor
Inhibitor
/
Non
inhibitor
Non-
substrate
5
9
c
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Inhibitor
2.2467
Non-carcinogen
/
Non
inhibitor
Substrate
a
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Non-
Inhibitor
Non-
Inhibitor
2.4766
2.3636
Non-carcinogen
Non-carcinogen
/
Non
inhibitor
Non-
substrate
9
b
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Non-
Inhibitor
Inhibitor
Inhibitor
/
Non
inhibitor
Non-
substrate
9
c
Non-
substrate
Non-
substrate
Substrate/inh
ibitor
Inhibitor
2.2467
2.1882
Non-carcinogen
Non-carcinogen
/
Non
inhibitor
substrate
Ciprofloxacin
Non-
substrate
Non-
substrate
Non-
substrate
Non-
inhibitor
Non-
inhibitor
/
Non
inhibitor
3
.4 Molecular Dynamics Study
The molecular dynamics simulation study was performed with OPLS-2005 force filed for 5ns
nanoseconds) simulation time with best-docked 5c:1D7U complex using Desmond 4 module
(

ACCEPTED MANUSCRIPT
(Schrodinger LLC, NY, release 2016). The total of 55106 atoms were present during the
simulation. The trajectories were collected at every 4.8 ps and numbers of frames were kept
at 250. After simulation with water as a solvent, we found that the complex was enough
stable for a period of 5ns (Figure 6-7).
Figure- 6 A] Showing the protein-ligand interaction throughout the simulation time of 5ns
(green-H-bond, purple-hydrophobic contacts, Pink-ionic contacts, and Blue-Water
bridges).Values more than 1 suggesting more contacts and corresponding to 100%. B]
Timeline representation plot after MD simulation time of 5ns.
Figure-7: A] A plot showing the properties corresponding with ligands after MD simulation
and B] RMSD plot for 5c:1D7U complex.

ACCEPTED MANUSCRIPT
3
.5 “HOMO–LUMO theory” and (“FMO” approach)
All the compounds 5(a-c) and 9(a-c) are optimized with “B3LYP/6-31g (d)” method in the
gas phase. “Highest Occupied Molecular Orbital”- i.e. “HOMO” and “Lowest Unoccupied
Molecular Orbital”- i.e. “LUMO” are the most important orbitals in a molecule. Analyzing
the Energy gap (ELUMO – EHOMO) is important, as these values are related to the reactivity of
molecules [34]. A molecule with a high chemical reactivity and low kinetic stability is
generally accomplice with a small energy gap between frontier orbitals. A molecule when
energized, it easily loses an electron, as “HOMO energy” is directly related to “ionization
potential”. On the other hand “LUMO energy” directly related with “electron affinity”, as it
accepts an electron. “HOMO – LUMO” theory is used to compare with biological activities
of newly synthesized dyes 5(a-c) and 9(a-c). The (ELUMO – EHOMO) values are gathered in
Table 7 and also presented in Figure 8. It is observed that 9(a-c) has less “HOMO-LUMO”
gap compared to 5(a-c). So, 9(a-c) should exhibit better biological activity compared to 5(a-
c). This correlation confirmed by “REMA assay method”. Dyes 9(a-c) shown comparatively
better activities than dyes 5(a-c) for “S.aureus” bacteria.
Table 7: The tabular representation for calculation of “HOMO-LUMO energy gap” for
synthesized compounds 5(a-c) and 9(a-c).
HOMO Energy
LUMO Energy
E LUMO-EHOMO
eV
Compound
Hartree
eV
Hartree
eV
5
a
-0.2064
-0.2050
-5.61
-5.58
-0.0784
-0.0768
-2.13
-2.09
3.48
3.49
5
b
5
9
c
a
-0.1964
-0.2113
-5.34
-5.75
-0.0634
-0.0940
-1.73
-2.56
3.62
3.19
9
b
-0.2102
-0.2029
-5.72
-5.52
-0.0924
-0.0793
-2.56
-2.16
3.20
3.36
9
c

ACCEPTED MANUSCRIPT
Figure 8: The graphical representation for the calculation of “HOMO-LUMO energy gap”
for 5(a-c) and 9(a-c).
4
. Conclusion
In the present work, six new 5(a-c) and 9(a-c) heterocyclic azo compounds are synthesized.
These azo clubbed derivatives were characterized using various spectroscopic techniques
1
such as H NMR, FTIR, UV–Visible, fluorescence spectroscopy, LC-MS, and elemental
analysis. All compounds are emissive and shown Stoke’s shifts of around 81-105nm. All
compounds are screened against antibacterial activity by using REMA method. 5a and 9a
showed moderate activity against Gram-negative (Escherichia coli) strain. Comparative
HOMO-LUMO studies also performed and it observed that 9(a-c) molecules have less
HOMO-LUMO gap compared to 5(a-c). Compounds which have comparative less HUMO-
LUMO gap shown good activity. Molecular docking protocols were performed for different
target proteins (PDB ids-2XCS, 2XCT, and 1D7U).The results after docking studies were
correlated with the actual in-vitro data. Molecular Dynamics Study showed that the complex
was stable for common bacterial target protein 1D7U complex with most docked molecule 5c
during 5 ns simulation time. In summary, our studies indicated that these complexes have an
affinity for DNA. Furthermore, the docking simulation results obtained in present work
suggests the future applications of these azo clubbed compounds as antibacterial agents.

ACCEPTED MANUSCRIPT
Accordingly, after comparing ADME and molecular properties of our compounds to standard
ciprofloxacin, our compounds may be effectively optimized into lead compounds for potent
antimicrobial agents in future.
Acknowledgment
Authors (CWG and VRM) are thankful to Principal Scientific Adviser to Government of
India (PSA to GOI) for JRF (Junior Research Fellowship) and financial support.
5
. References:
1] J.J.S.-G. Krasaka, Synthesis and Properties of Monoazo Disperse Dyes Derived from
-Amino-5-nitro [2,1] benzisothiazole, Dye. Pigment. 8 (1987) 345–352.
[
3
doi:10.1016/0143-7208(87)85024-6.
[
[
2] M.A. Satam, R.K. Raut, N. Sekar, Dyes and Pigments and comparison with 2-naphthol
analogs, Dye. Pigment. 96 (2013) 92–103. doi:10.1016/j.dyepig.2012.07.019.
3] S.K. Lanke, N. Sekar, Coumarin Push-Pull NLOphores with Red Emission:
Solvatochromic and Theoretical Approach, J. Fluoresc. 26 (2016) 949–962.
doi:10.1007/s10895-016-1783-6.
[
[
[
[
4] M.M. Jadhav, I.A. Alswaidan, L. Rhyman, P. Ramasami, N. Sekar, TD-DFT
Investigation of 2,5-Bis(2-benzothiazolyl)hydroquinone and 2,5-Bis(benzo[d]thiazol-
2
0
-yl)-4-methoxyphenol, J. Solution Chem. 46 (2017) 1005–1023. doi:10.1007/s10953-
17-0628-5.
5] T. Tao, F. Xu, X.C. Chen, Q.Q. Liu, W. Huang, X.Z. You, Comparisons between azo
dyes and Schiff bases having the same benzothiazole/phenol skeleton: Syntheses,
crystal structures and spectroscopic properties, Dye. Pigment. 92 (2012) 916–922.
doi:10.1016/j.dyepig.2011.09.008.
6] J. Graham, C.E. Wong, J. Day, E. McFaddin, U. Ochsner, T. Hoang, C.L. Young, W.
Ribble, M.A. DeGroote, T. Jarvis, X. Sun, Discovery of Benzothiazole Amides as
Potent Antimycobacterial Agents, Bioorg. Med. Chem. Lett. (2018) 1–5.
doi:10.1016/j.bmcl.2018.08.026.
7] S.K. Maddili, Z.Z. Li, V.K. Kannekanti, R.R.Y. Bheemanaboina, B. Tuniki, V.K.R.
Tangadanchu, C.H. Zhou, Azoalkyl ether imidazo[2,1-b]benzothiazoles as potentially
antimicrobial agents with novel structural skeleton, Bioorganic Med. Chem. Lett. 28
(2018) 2426–2431. doi:10.1016/j.bmcl.2018.06.016.
[
[
8] A. Rouf, C. Tanyeli, Bioactive thiazole and benzothiazole derivatives, Eur. J. Med.
Chem. 97 (2015) 911–927. doi:10.1016/j.ejmech.2014.10.058.
9] P.C. Sharma, A. Sinhmar, A. Sharma, H. Rajak, D.P. Pathak, Medicinal significance of
benzothiazole scaffold: An insight view, J. Enzyme Inhib. Med. Chem. 28 (2012) 240–
2
66. doi:10.3109/14756366.2012.720572.
[
[
10] M.T. El Sayed, M.A.M.S. El-Sharief, E.S. Zarie, N.M. Morsy, A.R. Elsheakh, A.
Voronkov, V. Berishvili, G.S. Hassan, Design, synthesis, anti-inflammatory activity
and molecular docking of potential novel antipyrine and pyrazolone analogs as
cyclooxygenase enzyme (COX) inhibitors, Bioorganic Med. Chem. Lett. 28 (2018)
9
52–957. doi:10.1016/j.bmcl.2018.01.043.
11] S. Rasapalli, Y. Fan, M. Yu, C. Rees, J.T. Harris, J.A. Golen, J.P. Jasinski, A.L.
Rheingold, S.M. Kwasny, T.J. Opperman, Detour of prenostodione synthesis towards
pyrazolones for antibacterial activity, Bioorganic Med. Chem. Lett. 23 (2013) 3235–

ACCEPTED MANUSCRIPT
3
238. doi:10.1016/j.bmcl.2013.03.123.
[
12] D. Renck, P. Machado, A.A. Souto, L.A. Rosado, T. Erig, M.M. Campos, C.B. Farias,
R. Roesler, L.F.S.M. Timmers, O.N. De Souza, D.S. Santos, L.A. Basso, Design of
Novel Potent Inhibitors of Human Uridine Phosphorylase- 1: Synthesis, Inhibition
Studies, Thermodynamics, and in Vitro In fl uence on 5 ‑ Fluorouracil Cytotoxicity,
5
6 (2013) 8892–8902. doi:10.1021/jm401389u.
[
[
[
[
[
13] V.A. Joseph, J.H. Pandya, R.N. Jadeja, Syntheses , crystal structure and biological
evaluation of Schiff bases and copper complexes derived from 4-formylpyrazolone, J.
Mol. Struct. 1081 (2015) 443–448. doi:10.1016/j.molstruc.2014.10.056.
14] V. Kumar, K. Kaur, G. Kumar, A. Kumar, European Journal of Medicinal Chemistry
Pyrazole containing natural productsꢀ: Synthetic preview and biological signifi cance,
Eur. J. Med. Chem. 69 (2013) 735–753. doi:10.1016/j.ejmech.2013.08.053.
15] F. Karc, F. Karc, A. Demirçal, M. Yamaç, Synthesis , solvatochromic properties and
antimicrobial activities of some novel pyridone-based disperse disazo dyes, J. Mol.
Liq. 187 (2013) 302–308. doi:10.1016/j.molliq.2013.08.005.
16] Y. Cui, G. Qian, L. Chen, Z. Wang, M. Wang, Synthesis and nonlinear optical
properties of a series of azo chromophore functionalized alkoxysilanes, Dye. Pigment.
7
7 (2008) 217–222. doi:10.1016/j.dyepig.2007.05.005.
17] M.S. Refat, M.Y. El-sayed, A. Majid, A. Adam, Cu ( II ), Co ( II ) and Ni ( II )
complexes of new Schiff base ligandꢀ: Synthesis , thermal and spectroscopic
characterizations, J. Mol. Struct. 1038 (2013) 62–72.
doi:10.1016/j.molstruc.2013.01.059.
[
[
[
18] F. Qiu, Y. Cao, H. Xu, Y. Jiang, Synthesis and properties of polymer containing azo-
dye chromophores for nonlinear optical applications, Dye. Pigment. 75 (2007) 454–
4
59. doi:10.1016/j.dyepig.2006.06.037.
19] B. Çatikkaş, E. Aktan, E. Yalçin, Vibrational and electronic investigations, NLO,
FMO analysis on a hetarylazoindole disperse dye by density functional theory, J. Mol.
Struct. 1117 (2016) 218–226. doi:10.1016/j.molstruc.2016.03.074.
20] V.R. Mishra, C.W. Ghanavatkar, S.I. Qureshi, H.K. Chaudhari, N. Sekar, Design,
Synthesis, antimicrobial activity and computational studies of novel azo linked
substituted benzimidazole, benzoxazole and benzothiazole derivatives, Comput. Biol.
Chem. 78 (2019) 330–337. doi:10.1016/j.compbiolchem.2019.01.003.
[
[
21] N. Hassan, A.Z. El-sonbati, M.G. El-desouky, Synthesis , characterization , molecular
docking and DNA binding studies of Cu ( II ), Ni ( II ), Zn ( II ) and Mn ( II )
complexes, J. Mol. Liq. 242 (2017) 293–307. doi:10.1016/j.molliq.2017.07.019.
22] W.H. Mahmoud, G.G. Mohamed, S.Y.A. Mohamedin, Spectroscopic characterization,
thermal, antimicrobial and molecular docking studies on nano-size mixed ligand
complexes based on sudan III azodye and 1,10-phenanthroline, J. Therm. Anal.
Calorim. 130 (2017) 2167–2184. doi:10.1007/s10973-017-6482-2.
[
[
[
23] W.H. Mahmoud, F.N. Sayed, G.G. Mohamed, Synthesis, characterization and in vitro
antimicrobial and anti-breast cancer activity studies of metal complexes of novel
pentadentate azo dye ligand, Appl. Organomet. Chem. 30 (2016) 959–973.
doi:10.1002/aoc.3529.
24] A. Mohammadi, B. Khalili, M. Tahavor, Novel push-pull heterocyclic azo disperse
dyes containing piperazine moiety: Synthesis, spectral properties, antioxidant activity
and dyeing performance on polyester fibers, Spectrochim. Acta - Part A Mol. Biomol.
Spectrosc. 150 (2015) 799–805. doi:10.1016/j.saa.2015.06.024.
25] S.N. Mali, H.K. Chaudhari, Computational Studies on Imidazo[1,2-a] Pyridine-3-
Carboxamide Analogues as Antimycobacterial Agents: Common Pharmacophore
Generation, Atom-based 3D-QSAR, Molecular dynamics Simulation, QikProp,

ACCEPTED MANUSCRIPT
Molecular Docking and Prime MMGBSA Approaches, Open Pharm. Sci. J. 5 (2018)
1
2–23. doi:10.2174/1874844901805010012.
[
26] G. M. J. Frisch, W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R.
Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M.
Caricato, X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg,
Gaussian 09, Revision C.01, Inc. Wallingford, CT. (2009) 2009–2009. doi:111.
27] A.D. Becke, A new mixing of Hartree–Fock and local density-functional theories, J.
Chem. Phys. 98 (1993) 1372. doi:10.1063/1.464304.
[
[
28] C. Lee, W. Yang, R.G. Parr, Development of the Colic-Salvetti correlation-energy into
a functional of the electron density formula Chengteh, Phys. Rev. B. 37 (1988) 785–
7
89. doi:10.1103/PhysRevB.37.785.
[
[
[
[
29] Glide., New York, NY:Schrodinger, LLC, (2017).
30] Qikprop, New York, NY: Schrodinger, LLC, (2017).
31] Prime., New York, NY: Schrodinger, LLC, (2017).
32] M.G. Holler, L.F. Campo, A. Brandelli, V. Stefani, Synthesis and spectroscopic
characterisation of 2-(2′-hydroxyphenyl)benzazole isothiocyanates as new fluorescent
probes for proteins, J. Photochem. Photobiol. A Chem. 149 (2002) 217–225.
doi:10.1016/S1010-6030(02)00008-4.
[
[
33] C.C. Chen, I.J. Wang, Synthesis of some pyridone azo dyes from 1-substituted 2-
hydroxy-6-pyridone derivatives and their colour assessment, Dye. Pigment. 15 (1991)
6
9–82. doi:10.1016/0143-7208(91)87008-B.
34] P.M. Chauhan, S.N. Thummar, K.H. Chikhalia, Design, synthesis, bioactivity, and
computational studies of some morpholine-clubbed coumarinyl acetamide and
cinnamide derivatives, J. Iran. Chem. Soc. 15 (2018) 1261–1277. doi:10.1007/s13738-
0
18-1324-0.
[
35] S.S. Bhat, N. Shivalingegowda, V.K. Revankar, N.K. Lokanath, M.S. Kugaji, V.
Kumbar, K. Bhat, Synthesis, structural characterization and biological properties of
phosphorescent iridium(III) complexes, J. Inorg. Biochem. 177 (2017) 127–137.
doi:10.1016/j.jinorgbio.2017.09.020.
[
[
[
36] N.M. Mallikarjuna, J. Keshavayya, Synthesis, spectroscopic characterization and
pharmacological studies on novel sulfamethaxazole based azo dyes, J. King Saud
Univ. - Sci. (2018). doi:10.1016/j.jksus.2018.04.033.
37] V.N. Malashkevich, P. Strop, J.W. Keller, J.N. Jansonius, M.D. Toney, Crystal
structures of dialkylglycine decarboxylase inhibitor complexes, J. Mol. Biol. 294
(1999) 193–200. doi:10.1006/jmbi.1999.3254.
38] F.A. Bassyouni, T.S. Saleh, M.M. Elhefnawi, S.I.A. El-Moez, W.M. El-Senousy, M.E.
Abdel-Rehim, Synthesis, pharmacological activity evaluation and molecular modeling
of new polynuclear heterocyclic compounds containing benzimidazole derivatives,
Arch. Pharm. Res. 35 (2012) 2063–2075. doi:10.1007/s12272-012-1204-6.
[
39] B.D. Bax, P.F. Chan, D.S. Eggleston, A. Fosberry, D.R. Gentry, F. Gorrec, I.
Giordano, M.M. Hann, A. Hennessy, M. Hibbs, J. Huang, E. Jones, J. Jones, K.K.
Brown, C.J. Lewis, E.W. May, M.R. Saunders, O. Singh, C.E. Spitzfaden, C. Shen, A.
Shillings, A.J. Theobald, A. Wohlkonig, N.D. Pearson, M.N. Gwynn, Type IIA
topoisomerase inhibition by a new class of antibacterial agents, Nature. 466 (2010)
9
35–940. doi:10.1038/nature09197.

ACCEPTED MANUSCRIPT
Synthesis, Bioactivities, DFT and in-silico appraisal of azo clubbed
Benzothiazole derivatives.
.
a
a
b
Chaitannya W. Ghanavatkar , Virendra R. Mishra , Suraj N. Mali . Dr. Hemchandra K.
b
a, *
Chaudhari , Nagaiyan Sekar
Highlights
•
•
•
Six new heterocyclic azo dyes are synthesised
They are emissive, showed Stoke’s shifts of around 81-105nm
They have moderate activity against Gram-negative (Escherichia coli) strain. DFT-
computed HOMO-LUMO studies also performed.
•
•
Docking studies on common bacterial targets (PDB ids-2XCS, 2XCT and 1D7U)
showed good results
Molecular Dynamics studies showed that the complex was stable for common
bacterial target protein 1D7U complex with most docked molecule 5c during 5ns
simulation time.
•
These complexes have moderate affinity for DNA.