Regioselective synthesis, antimicrobial evaluation and theoretical studies of 2-styryl quinolines

Article abstract of DOI:10.1039/c4ob02277g

2-Styryl quinolines (9a-l) have been synthesized regioselectively from 2-methyl-quinoline by using NaOAc in water acetic acid binary solvents and evaluated for their antibacterial activity against both Gram-positive and Gram-negative strains. Among these,

Full text of DOI:10.1039/c4ob02277g

View Article Online
View Journal
Organic &
Biomolecular
Chemistry
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: A. Kamal, R.
Abdul, S. Riyaz, P. Y, B. Moku, G. K. C., A. S. M. Hussaini, S. Balasubramanian and P. K. Machiraju, Org.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/obc

Page 1 of 12
Organic & Biomolecular Chemistry
Dynamic Article Links►
Journal Name
View Article Online
DOI: 10.1039/C4OB02277G
Cite this: DOI: 10.1039/c0xx00000x
www.rsc.org/xxxxxx
ARTICLE TYPE
Regioselective synthesis, antimicrobial evaluation and theoretical studies
of 2-styryl quinolines
Ahmed Kamal,a* Abdul Rahim,a Sd Riyaz,a Y Poornachandra,a Moku Balakrishna,a C Ganesh Kumar,a
Syed Mohammed Ali Hussaini,a B Sridhar,b and Pavan Kumar Machirajuc
5
Received (in XXX, XXX) XthXXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
DOI: 10.1039/b000000x
2ꢀStyryl quinolines (9a-l) have been synthesized regioselectively from 2ꢀmethylꢀquinoline by using NaOAc in water acetic acid binary
solvents and evaluated for their antibacterial activity against both Gramꢀpositive and Gramꢀnegative strains. Among these, the
compounds 12 and 8 were found to be active against both bacterial strains. Compounds 9b, 9f, 9g, 9i, 9j and 9k were most active among
10 the series exhibiting MIC values ranging between 1.9ꢀ31.2 µg/ml against different bacterial strains. Compounds 9j and 9k were found to
be as potent as standard drug ciprofloxacin against Micrococcus luteus, Klebsiella planticola and Staphylococcus aureus, respectively. In
addition, the compounds showed bactericidal activity, compound 9j was found to be better as compared to ciprofloxacin with MBC value
of 0.9 µg/ml against both M. luteus and K. planticola. The compounds also inhibited biofilm formation, compound 9j was found to be
equipotent to erythromycin against M. luteus and S. aureus MLS16. Further, theoretical studies such as druggable properties and PMI
15 plot have been carried out.
Staphylococcus pneumoniae in a mouse lung infection model and
also exhibited activity against MRSA.15
Introduction
Oneꢀthird of the world’s population are infected by
Since last few years, the molecular hybridization
bacterial pathogens, which results in two million fatalities per
year.1 Development of bacterial resistance to the current
20 antibiotics and development of multidrug resistant strains like
50 approach for quinolineꢀbased antibacterials with structural
diversification in the Cꢀ3 position of the quinoline has been
used.16ꢀ19 Recently, the new quinolineꢀbased antiꢀTB drug,
bedaquiline (2)(BQ, TMC207, R207910) was approved by
FDA.20 Chloroquine (3), primaquine (4), mefloquine (5) and
55 quinine (6) are examples of the drugs containing quinoline
scaffold (Fig. 1). On the basis of substitution pattern on quinoline
ring in these drugs and in continuation to our research to find
potent antimicrobial agents,21ꢀ25 we herein report the design and
regioselective synthesis of 2ꢀstyryl quinolines26 and their
methicillinꢀresistant Staphylococcus aureus (MRSA) is
a
significantly increasing threat to human health.2 Drug resistance
develops as a result of gene mutation, rearrangement and genetic
transfer between different bacteria.3 In addition, bacterial
25 resistance is induced by various cellular mechanisms involving
efflux pumps, target modification, or drug inactivation by
enzymes.4 Antibiotics have been shown to be 1000ꢀ to 1500ꢀfold
less active against bacteria that are confined within a biofilm than
against individual freeꢀform planktonic bacteria.5 These facts
30 emphasized the urgent need to develop new affordable drugs with
novel structural features, high potency, less toxicity and activity
against drug resistant organisms with new mode of action.
60 evaluation for antimicrobial, bactericidal and
activities.
antiꢀbiofilm
Quinoline scaffold has gathered an immense attention
among chemists as well as biologists as it is one of the key
35 building elements for many naturally occurring compounds. The
quinoline ring is endowed with various activities, such as antiꢀ
tuberculosis,6 antimalarial,7 antiꢀ inflammatory,8 anticancer,9
65
antibiotic,10
antiꢀhypertensive,11
tyrokinase
PDGFꢀRTK
inhibiting agents,12 and antiꢀHIV.13,14 Compared to the successful
40 development on new fluoroquinolones, research on chemistry of
new quinolineꢀbased antimicrobial drugs seems to be
underdeveloped. However, certain synthetic small molecules
based on quinine core were found to exhibit broadꢀspectrum of
antibacterial activity. Quinineꢀlike molecule (1) that acts by
45 inhibition of bacterial gyrase and topoisomerase IV was found to
70
Fig. 1: Quinoline based antibacterial agents.
be efficient against
a strain of flouroquinoloneꢀresistant
This journal is © The Royal Society of Chemistry [year] [journal], [year], [vol], 00–00 |1

Organic & Biomolecular Chemistry
Page 2 of 12
View Article Online
DOI: 10.1039/C4OB02277G
20 sodium acetate affords the traces of product. Similarly with
acetic solvent the reaction underwent but with low yield and
when we used sodium acetate in this solvent yield was slightly
increased. We did not observe any remarkable increase in the
yield when we used temperature 120 oC and 80 oC.
Chemistry
Intermediate
7 was synthesized by the known
procedure we reported previously.27 2ꢀaminobenzophenone was
reacted with acetyl acetone in presence of catalytic amount of
HCl in acetonitrile to afford intermediate 7. The structure of 7
5
1
was assigned on the basis of its H NMR, two singlet at δ 1.96
and δ 2.67 ppm strongly supports the presence of –CH3 and –
COCH3. Likewise two double doublets appeared at δ 7.39ꢀ7.44
and δ 7.56ꢀ7.62 with J = 8.3 Hz, 1.51 Hz confirmed the presence
10 of two quinoline protons. To obtain final compounds 9aꢀl, we
used a new methodology in which compound 7 was condensed
with different substituted benzaldehydes (8a-l) in presence of
sodium acetate in equal ratio of water and acetic acid as green
solvents (Table 2). In the beginning, reaction between 2ꢀmethylꢀ
15 3ꢀacetylꢀ4ꢀphenyl quinoline and 4ꢀnitro benzaldehyde was carried
out in water at room temperature and at 120 oC, the completion of
the reaction was monitored by TLC (scheme 1). It was observed
that the reaction did not proceed even until 16 hours but the use
of
25
Scheme 1: Reaction of 7a with 8d under various conditions
Table 1: Optimization of the reaction conditions
Entry
1
2
3
4
5
6
7
Solvent
H2O
H2O
AcOH
AcOH
Base
ꢀa
Temp (oC)
120
Time (h)
Yielda(%)
Nil
Trace
20
16
16
16
8
8
8
NaOAc
120
120
120
80
80
80
120
ꢀa
NaOAc
NaOAc
ꢀa
NaOAc
NaOAc
38
35
44
69
AcOH
AcOH:H2Ob
AcOH:H2Ob
AcOH:H2Ob
8
8
8
83
a No buffer used, b 1:1 Solvent used.
Likewise when we moved to the binary mixture of
30 acetic acid and water we found that the use of sodium acetate
and refluxing temperature at 120 oC provides us very good
yield. The compound 7 was having labile methyl group at Cꢀ2
and at Cꢀ3, so we intend to condense only Cꢀ2 methyl under
neutral conditions by using sodium acetate as buffer in water
35 and in an acetic acid medium.
The structure of the target compounds were assigned by
1
their H and 13C NMR, IR and HRMS data.28 The coupling
1
45 constants values obtained from H NMR data indicate that the
geometry of the double bond in the product is predominantly
trans. Further, Xꢀray crystallographic study was performed on
9k to precisely determine the position of double bond that is
whether it was formed on the carbon of methyl group adjacent
50 to carbonyl at Cꢀ3 position of compound 7b or at Cꢀ2 position.
The Xꢀray crystal structure of the compound 9k has confirmed
the regioselective formation of double bond at Cꢀ2 position
through the application of sodium acetate in water acetic acid
solvents (Fig. 2). To the best of our knowledge, the synthesized
55 compounds and method used were not reported previously in
In conclusion, reaction optimization showed that in
basic medium, the Cꢀ3 methyl was condensed to give chalcone
as the product, but in acidic medium the desired compound
formed with low yield. So we tried the binary mixture of water
40 and acetic acid in presence of sodium acetate which furnished
the desired results (Table 1). Synthetic route for desired
compounds 9a-l is outlined in Scheme 2.
the
literature.
Scheme.2: Synthesis of 2ꢀstyrylquinoline
2
|
Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 3 of 12
Organic & Biomolecular Chemistry
View Article Online
DOI: 10.1039/C4OB02277G
Table 2: Synthesis of 2ꢀstyrylquinoline from quinoline and aldehyde
Yieldc
M.P (oC)
(%)
Entry
Quinolines (7a-b)
Aldehydes (8a-l)
Products (9a-l)
Time (h)
1
2
3
4
10
80
201ꢀ203
8a
9a
7a
8b
12
75
213ꢀ215
7a
9b
85
209ꢀ211
7a
8c
8
9c
7a
8d
8.5
86
246ꢀ248
9d
7a
8e
5
9
85
180ꢀ182
9e
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |3

Organic & Biomolecular Chemistry
Page 4 of 12
View Article Online
DOI: 10.1039/C4OB02277G
6
7a
8f
12
83
163ꢀ165
9f
7a
7
8g
14
81
159ꢀ161
9g
7a
8h
8
13
82
172ꢀ174
9h
9
7a
8i
15
82
230ꢀ232
9i
10
7b
8j
8
90
208ꢀ210
9j
4|
Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 5 of 12
Organic & Biomolecular Chemistry
View Article Online
DOI: 10.1039/C4OB02277G
8k
7b
11
9
88
217ꢀ219
9k
8k
8l
7b
12
14
85
243ꢀ245
9
9l
cIsolated yield.
15
Biological evaluation
Antimicrobial activity
Compounds 9a-l were tested for antimicrobial
activity against both Gramꢀpositive and Gramꢀnegative
20 bacterial strains. The results illustrate that out of 12,
compounds, 8 compounds exhibited promising antimicrobial
activity (Table 3) and the bactericidal effects with minimum
bactericidal concentration (MBC) values ranged between 0.9 to
31.2 µg/ml. Compound 9a was found to be active against
25 different Gramꢀpositive bacterial strains with MIC values
ranging between 15.6 to 31.2 µg/ml; however, it was more
promising against Gramꢀnegative bacteria with MIC value as
low as 3.9 µg/ml against P. aeruginosa MTCC 2453.
Compound 9b showed lowest MIC value of 1.9 µg/ml against
30 M. luteus MTCC 2470 and 3.9 µg/ml against S. aureus MTCC
96, B. subtilis MTCC 121 and K. planticola MTCC 530.
Compound 9f was found to be active against S. aureus MTCC
96 with MIC value of 1.9 µg/ml and showed good activity
against M. luteus MTCC 2470, B. subtilis MTCC 121, E. coli
35 MTCC 739, P. aeruginosa MTCC 2453 and K. planticola
MTCC 530 with MIC value of 3.9 µg/ml. Compound 9g
showed MIC value of 1.9 µg/ml against B. subtilis MTCC 121
and MIC value of 3.9 µg/ml against S. aureus MTCC 96.
Compound 9i was found to be more promising against M.
40 luteus MTCC 2470, S. aureus MTCC 96 and K. planticola
MTCC 530 exhibiting MIC value of 1.9 µg/ml and was good
against B. subtilis MTCC 121, S. aureus MLS16 MTCC 2940
and B. subtilis MTCC 121.
Fig. 2 : ORTEP of compound 9k. A view of AW80, showing the atomꢀ
labeling scheme. Displacement ellipsoids are drawn at the 30%
probability level and H atoms are represented by circles of
arbitrary radii. (CCDC No: 1023840)
5
10
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |5

Organic & Biomolecular Chemistry
Page 6 of 12
Dynamic Article Links►
Journal Name
View Article Online
DOI: 10.1039/C4OB02277G
Cite this: DOI: 10.1039/c0xx00000x
www.rsc.org/xxxxxx
ARTICLE TYPE
Table 3: Antimicrobial activity of the compounds against several standard strains
Minimum inhibitory concentration (µg/ml)
Entry
1
2
3
4
5
6
7
8
Compound
M.la
15.6±0.12
1.9±0.08
>125
>125
>125
3.9±0.13
7.8±0.16
>125
1.9±0.14
0.9±0.12
1.9±0.11
>125
S.ab
31.2±0.36
3.9±0.16
>125
S.ac
31.2±0.38
7.8±0.36
>125
B.sd
15.6±0.26
3.9±0.22
>125
E.ce
7.8±0.18
7.8±0.32
>125
P.af
3.9±0.24
7.8±0.28
>125
>125
>125
3.9±0.16
7.8±0.32
>125
7.8±0.21
1.9±0.22
1.9±0.18
31.2±0.42
0.9±0.08
ꢀi
K.pg
15.6±0.32
3.9±0.21
>125
>125
>125
3.9±0.28
15.6±0.24
>125
1.9±0.18
0.9±0.07
31.2±0.32
>125
C.ah
9a
9b
9c
9d
9e
9f
9g
9h
9i
ꢀi
ꢀi
ꢀi
>125
>125
>125
>125
ꢀi
>125
>125
>125
>125
ꢀi
1.9±0.12
3.9±0.22
>125
7.8±0.32
15.6±0.24
>125
3.9±0.18
1.9±0.16
>125
3.9±0.18
15.6±0.25
>125
ꢀi
ꢀi
ꢀi
9
1.9±0.11
1.9±0.13
0.9±0.08
>125
3.9±0.12
1.9±0.16
31.2±0.28
>125
3.9±0.28
1.9±0.22
1.9±0.24
>125
7.8±0.18
3.9±0.26
1.9±0.12
31.2±0.38
0.9±0.07
ꢀi
ꢀi
10
11
12
9j
9k
9l
ꢀi
ꢀi
ꢀi
ꢀi
Ciprofloxacin (standard)
Miconazole (standard)
0.9±0.12
0.9±0.09
0.9±0.10
0.9±0.11
0.9±0.11
ꢀi
ꢀi
ꢀi
ꢀi
ꢀi
7.8±0.14
aMicrococcus luteus MTCC 2470, bStaphylococcus aureus MTCC 96, cStaphylococcus aureus MLS16 MTCC 2940, dBacillus subtilis MTCC 121,
eEscherichia coli MTCC 739, Kseudomonas aeruginosa MTCC 2453, Klebsiella planticola MTCC 530, hCandida albicans MTCC 3017,i No activity.
f
g
Bactericidal activity
5
Compound 9j was found to be most active among the
20
Compounds were evaluated for bactericidal activity
(Table 4) and they exhibited good to promising activity against
all the tested bacterial strains. All the compounds showed
bactericidal effect on different strains with MBC value ranging
from 3.9 to 62.5 µg/ml. Compound 9j was found to be better in
25 this regard as compared to ciprofloxacin with MBC value of
0.9 µg/ml against M. luteus MTCC 2470 and promising against
S. aureus MLS16 MTCC 2940, P. aeruginosa MTCC 2453 and
K. planticola MTCC 530. Compound 9k was also found
promising against Bacillus subtilis MTCC 121 with MBC value
30 of 1.9 µg/ml.
series and equipotent to the standard drug ciprofloxacin with
MIC value of 0.9 µg/ml against M. luteus MTCC 2470 and K.
planticola MTCC 530. Compound 9j was found to be more
promising against all the remaining bacterial strains used
10 withMIC value of 1.9 µg/ml. For E. coli MTCC 739, the MIC
value observed was 3.9 µg/ml. Compound 9k was found to be
equipotent to ciprofloxacin against S. aureus MTCC 96 and
showed excellent MIC value of 1.9 µg/ml against M. luteus
15 MTCC 2470, B. subtilis MTCC 121 E.coli MTCC 739 and P.
aeruginosa MTCC 2453.
Table 4: MBC values of compounds against several bacterial strains
Minimum bactericidal concentration (µg/ml)
Entry
Compound
M.la
S.ab
S.ac
B.sd
E.ce
P.af
K.pg
1
2
3
4
5
6
7
8
9a
9b
9f
9g
9i
9j
9k
9l
31.2±0.46
3.9±0.28
7.8±0.34
15.6±0.42
3.9±0.18
0.9±0.08
3.9±0.22
>125
31.2±0.24
3.9±0.18
3.9±0.26
7.8±0.32
3.9±0.16
3.9±0.22
3.9±0.14
>125
62.5±0.42
15.6±0.36
15.6±0.32
31.2±0.28
7.8±0.24
1.9±0.11
31.2±0.28
>125
31.2±0.38
7.8±0.12
3.9±0.36
3.9±0.28
7.8±0.26
3.9±0.14
1.9±0.22
>125
15.6±0.26
7.8±0.35
7.8±0.34
15.6±0.26
15.6±0.28
7.8±0.28
3.9±0.16
62.5±0.52
0.58±0.08
7.8±0.22
15.6±0.26
3.9±0.22
15.6±0.38
7.8±0.14
1.9±0.16
3.9±0.24
62.5±0.48
1.17±0.08
31.2±0.22
3.9±0.28
7.8±0.26
31.2±0.18
3.8±0.24
0.9±0.08
62.5±0.35
>125
±
Ciprofloxacin (standard)
1.17±0.11
0.58±0.09
1.17±0.12
0.58±0.06
0.58±0.09
Anti-biofilm activity
Compounds exhibiting antibacterial and bactericidal
properties were also checked for bacterial biofilm inhibition
35 (Table 5). They were found to inhibit the biofilm formation
with IC50 values ranging between 0.3 and 30 µg/ml. Compound
9j was found to be potent as compared to that of erythromycin
against M. luteus MTCC 2470, S. aureus MLS16 MTCC 2940
and P. aeruginosa MTCC 2453. However, it was observed that
40 not even a single compound was active against the fungal strain
Candida albicans MTCC 3017 even at the maximum tested
concentration
(125µg/ml).
45
This journal is © The Royal Society of Chemistry [year] [journal], [year], [vol], 00–00 |6

Page 7 of 12
Organic & Biomolecular Chemistry
View Article Online
DOI: 10.1039/C4OB02277G
Table 5: Antiꢀbiofilm activity of compounds against different strains.
IC50 values (µg/ml)
Entry
Comp
M.la
S.ab
S.ac
B.sd
E.ce
P.af
K.pg
1
9a
9b
9f
9g
9i
22.3 ± 0.54
2.4 ± 0.16
3.1 ± 0.13
6.8 ± 0.22
2.8 ± 0.16
0.3 ± 0.11
1.2 ± 0.09
0.3 ± 0.08
25.3 ± 0.67
3.9 ± 0.15
2.9 ± 0.16
6.1 ± 0.22
3.1 ± 0.51
2.6 ± 0.13
3.1 ± 0.26
0.2 ± 0.07
29.5 ± 0.66
10.1 ± 0.38
9.2 ± 0.28
21.6 ± 0.56
4.2 ± 0.21
0.6 ± 0.12
15.6 ± 0.34
0.6 ± 0.08
18.4 ± 0.63
3.2 ± 0.16
2.1 ± 0.16
2.6 ± 0.22
4.6 ± 0.24
2.6 ± 0.12
0.8 ± 0.21
0.3 ± 0.11
6.2 ± 0.42
3.3 ± 0.28
4.2 ± 0.26
11.2 ± 0.44
8.1 ± 0.42
2.9 ± 0.24
2.6 ± 0.12
0.2 ± 0.09
3.2 ± 0.12
7.2 ± 0.52
2.9 ± 0.18
8.2 ± 0.44
2.8 ± 0.22
0.6 ± 0.12
2.2 ± 0.23
0.5 ± 0.11
16.9 ± 0.58
1.3 ± 0.12
6.1 ± 0.32
18.7 ± 0.44
1.1 ± 0.18
0.2 ± 0.08
42.3 ± 0.51
0.1 ± 0.05
2
3
4
5
6
7
9j
9k
Erythromycin
The structure–activity relationship study revealed
that NO2 group on quinoline ring was important for
antimicrobial, bactericidal as well as for antiꢀbiofilm activity
against all the tested strains. However, this NO2 group if
present on benzene ring attached to double bond (styryl
benzene) was found to be undesirable for activity. Similarly,
the OCF3 and 3,4,5ꢀtrimethoxy groups on styryl benzene ring
5
10 were found essential for activity against all strains. It was
observed that if both NO2 and OCF3 groups were present then
the compound exhibited activity with an increase in MIC value.
The activity of compound 9f against S. aureus was only due to
the presence of OCF3. Likewise, the presence of 3,5ꢀdiCF3,
15 OMe, OH, Cl groups on the styryl benzene ring were
responsible for the activity.
Comparison with FDA-approved drugs and PMI plot
40
Fig.4: PMI plot of our group of molecules relative to 1011 FDAꢀ
approved drugs. The PMI calculations involved aligning each molecule
to principal moment axes by using SYBYL and the normalized PMI
values were calculated by using inꢀhouse software.
45
In addition, the synthesized compounds were plotted
according to the normalized principal moment of inertia (PMI)
formalism of Sauer and Schwartz.32 Since molecular shape and
biological activity are intricately related, the screening of
molecules that have a higher degree of builtꢀin molecularꢀshape
50 diversity translates into a greater probability of discovering
compounds with biological activity. The three corners of the
isosceles triangle of the PMI plot are dominated by rods,
spheres, and discs, respectively (the shapes are representations
of the overall shape of the constituent molecules). From the
55 graph, it is clear that the FDA approved drugs cover the left
edge of the PMI space taking shapes intermediate between rods
and discs, 2ꢀstyryl quinolines (9a-l) falling under the same area
where the drug compounds fall in the graph. 2ꢀstyryl quinolines
(9a-l) are falling at the top of the left edge of the PMI space
60 (Fig. 4).33 The bioactivity track record of drug compounds is
wellꢀestablished. It can be said that the similar shapes of our
compounds to those of drug compounds will increase the
likelihood of discovering biologically relevant molecules by
using this method.
20
Fig.3: 1011 FDAꢀapproved drugs (lightꢀblue dots), as reported in the
GOSTAR database (GVK Bioscience proprietary database)
Using different molecular scaffolds from various
25 drugs, we assessed the skeletal diversity that was afforded by
the 2ꢀstyryl quinolines (9a-l) and their related chemical
descriptors by using in silico methods. We plotted them in
chemical space plots that corresponded to a set of six key
descriptors (i.e. polar surface area (PSA), solubility, hydrogen
30 bond acceptor (HBA), hydrogen bond donor (HBD), logA, and
logD) relative to 1011 FDA approved drugs (lightꢀblue dots),
as reported in the GOSTAR database (Fig. 1(a) )29ꢀ31. The plots
showed that these quinolines (Fig. 3), darkꢀgreen dots) are not
“outliers” with respect to these parameters when compared to
35 marketed drugs.
65 Conclusion
2ꢀStyrylquinolines (9a-l) have been synthesized
regioselectively from 2ꢀmethylꢀ3ꢀacetylꢀ4ꢀphenyl quinoline by
using sodium acetate in binary system (water:acetic acid) as a
green solvent. These compounds were further evaluated for
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |7

Organic & Biomolecular Chemistry
Page 8 of 12
View Article Online
DOI: 10.1039/C4OB02277G
their antiꢀmicrobial, bactericidal and biofilm inhibition
activities. All the compounds were found to be active and few
of them showed promising to excellent activities in the range
between 0.9ꢀ3.9 µg/ml. The skeletal diversity and related
chemical descriptors obtained from these compounds when
compared with 1011 FDA approved drugs, aligns in the same
region where the drugs lies in the plot. Similarly, the PMI plot
showed that they are falling under the same area where the
drug compounds appear in the graph. Based on the biological
55 benzaldehyde stirred for
5
min and 10 equivalents of
NaOAc was added to this solution. Now reaction kept under
o
reflux 120 C for 8ꢀ16 hours. Completion of reaction checked
by TLC .After rotary evaporation, reaction mixture was
neutralized with NaHCO3 and water (5ml) and chloroform
60 (20ml) were added and the aqueous layer was extracted with
chloroform (2x25ml). The combined organic layer was dried
over anhydrous Na2SO4 and concentrated by rotary evaporation
to afford crude product which was further purified by column
chromatography using ethyl acetate and hexane as solvent
5
10 and theoretical data obtained, it can be concluded that the
synthesized quinoline compounds have the potential to be
explored for further optimization.
65 system.
(E)ꢀ1-(2-( 4-Chlorostyryl )-4-phenylquinolin-3-yl ) ethanone
(9a).
Yields 80%; mp: 201ꢀ203 oC; 1H NMR (500 MHz, CDCl3): δ
ACKNOWLEDGEMENTS
2.07 (s, 3H), 7.16 (d, J=15.41 Hz, 1H), 7.34ꢀ7.39 (m, 3H),
The authors A.R. and M.B. are thankful to UGC, New Delhi
15 and Y.P. is thankful to CSIR, New Delhi for the award of
research fellowship. The author S.R. is thankful for the
financial support under the 12th Five Year plan project
‘Affordable Cancer Therapeutics (ACT)’ (CSC0301).
70 7.44ꢀ7.47
( m, 2H), 7.52ꢀ7.55 (m, 5H), 7.60ꢀ7.62 (d,
J=7.93,1H); 7.71ꢀ7.76 (m, 1H); 8.01ꢀ8.04 (d, J=15.41 Hz, 1H),
8.15ꢀ8.17 (d, J=8.39 Hz, 1H); 13C NMR (125 MHz, CDCl3): δ
32.82, 124.57, 125.61, 126.19, 126.87, 128.72, 128.76, 128.89,
128.95, 129.52, 130.06, 130.41, 134.46, 134.99, 135.14,
75 135.32, 144.54, 147.92, 149.82, 205.81; IR(KBr): ʋ 3423,
2923, 2853, 2361, 1654, 1508, 1482, 1122, 1092, 967, 765, 669
cmꢀ1; MS–ESIMS: m/z 384 (M+H)+; HR ESIMS: m/z calcd
Experimental section
20 I. Chemistry
for C25H19ClNO: 384.1149; found: 384.1152.
(E)ꢀ1-(2-(4-methoxystyryl)-4-phenylquinolin-3-yl) ethanone
80 (9b).
All chemicals and reagents were obtained from Aldrich
(Sigma–Aldrich, St. Louis, MO, USA) or AlfaAesar (Johnson
Matthey Company, Ward Hill, MA, USA). Reactions were
monitored by TLC, performed on silica gel glass plates
25 containing 60 Fꢀ254, and visualization on TLC was achieved
by UV light or iodine indicator. Column chromatography was
performed with Merck 60–120 mesh silica gel. 1H and 13C
NMR spectra were recorded on Gemini VarianꢀVXRꢀunity
(200, 400, 500 MHz) or Bruker UXNMR/XWINꢀNMR (300
30 MHz) instruments. Chemical shifts (δ) are expressed in ppm
relative to internal standard TMS. Multiplicities of NMR
signals are represented as singlet (s), doublet (d), doublet of
doublet (dd), triplet (t), quartet (q) and multiplet (m). ESI
spectra were recorded on Micro mass, Quattro LC using ESI+
35 software with capillary voltage 3.98 kV and ESI mode positive
ion trap detector.
Yields 75%; mp: 213ꢀ215 oC; 1H NMR (500 MHz, CDCl3): δ
2.08 (s, 3H), 3.84 (s, 3H) 6.91ꢀ6.93 (d, J=8.69 Hz, 2H), 7.05ꢀ
7.08 (d, J=15.41 Hz, 1H), 7.36ꢀ7.39 (m, 2H), 7.40ꢀ7.44 ( m,
1H), 7.53ꢀ7.55 (m, 3H), 7.56ꢀ7.59 (m, 3H); 7.71ꢀ7.74 (m, 1H);
85 8.02ꢀ8.05 (d, J=15.41 Hz, 1H), 8.13ꢀ8.15 (d, J=8.39 Hz, 1H);
13C NMR (125 MHz, CDCl3): δ 32.84, 55.32, 114.12, 121.80
125.44, 126.15, 126.48, 128.63, 128.82, 129.05, 129.31,
129.40, 130.07, 130.22, 134.43, 135.24, 136.35, 144.23,
147.96, 150.44, 160.23, 205.95; IR(KBr): ʋ 3423, 2924, 2836,
90 2360, 1632, 1603, 1508, 1483, 1260, 1247, 1158, 1025, 971,
835, 811, 768, 755, 706 cmꢀ1; MS–ESIMS: m/z 380 (M+H)+;
HR ESIMS: m/z calcd for C26H22NO2: 380.1645; found:
380.1647.
(E)ꢀ1-(2-(4-methoxy-3-nitrostyryl)-4-phenylquinoline-3-yl)
95 ethanone (9c).
Yields 85%; mp: 209ꢀ211 oC; 1H NMR (500 MHz, CDCl3): δ
1. General procedure for the synthesis of compounds (7a-b).
2.07 (s, 3H), 4.00 (s, 3H) 7.10ꢀ7.12 (d, J=8.85 Hz, 1H), 7.13ꢀ
7.16 (d, J=15.41 Hz, 1H), 7.38ꢀ7.40 (m, 2H), 7.44ꢀ7.48 ( m,
1H), 7.52ꢀ7.55 (m, 3H), 7.61ꢀ7.63 (dd, J=7.62, 0.91 Hz, 1H);
100 7.74ꢀ7.80 (m, 2H); 8.00ꢀ8.03 (d, J=15.56 Hz, 1H), 8.07ꢀ8.08 (d,
J=2.28 Hz, 1H), 8.14ꢀ8.16 (d, J=8.08 Hz, 1H); 13C NMR (125
MHz, CDCl3): δ 32.79, 56.67, 113.68, 124.42, 124.65, 125.64,
126.20, 126.98, 128.75, 129.00, 129.49, 130.04, 130.50,
132.87, 133.76, 134.38, 135.09, 139.82, 144.69, 147.88,
105 149.55, 152.91, 205.77; IR(KBr): ʋ 3428, 2927, 2360, 1696,
1617, 1564, 1530, 1441, 1415, 1353, 1270, 1208, 1165, 1086,
1016, 969, 821, 764, 705, 651 cmꢀ1; MS–ESIMS: m/z 425
(M+H)+; HR ESIMS: m/z calcd for C26H21N2O4: 425.1495;
found: 425.1494.
2ꢀaminobenzophenoneor5ꢀnitroꢀ2ꢀaminobenzophenone(5gm,
0.025mol) and acetyl acetone (2.53gm, 0.025mol) in 100ml
40 acetonitrile was stirred. To this solution catalytic amount of
HCl was added. Completion of reaction monitored by TLC.
After completion, reaction cool to room temperature then solid
observed. It was filtered and washed with hexane. Yield: 83%,
5.5g, white solid (7a).
45 3-Acetyl-2-methyl-4-phenylquinoline (7a).
White solid, yield 83%; 1H NMR (200 MHz, CDCl3): δ 8.04
(d, J=8.3 Hz, 1H ), 7.64ꢀ7.72( m, 1H ), 7.56ꢀ7.62 (dd, J=8.3,
1.51 Hz,1H),7.47ꢀ7.54 (m, 3H,), 7.39ꢀ7.44 (dd, J=8.3, 1.51 Hz,
1H,), 7.32ꢀ7.38 (m, 2H,), 2.67 (s,3H,), 1.96 (s, 3H,); IR(KBr): ʋ
50 3053, 3028, 1708, 1636, 1581, 1484, 1459, 1384, 1288, 1159,
1041, 880, 709, 651; ESIꢀMS: 262 (M+H)+.
110 (E)ꢀ1-(2-(4-nitrostyrl)-4-phenylquinolin-3-yl) ethanone (9d).
o
1
Yields 86%; mp: 246ꢀ248 C; H NMR (500 MHz, CDCl3): δ
2.06 (s, 3H), 7.34ꢀ7.37 (d, J=15.41 Hz, 1H), 7.38ꢀ7.41 (m, 2H),
7.47ꢀ7.52 (m, 1H), 7.53ꢀ7.57 ( m, 3H), 7.64ꢀ7.66 (d, J=7.78,
0.76 Hz, 1H), 7.74ꢀ7.76 (d, J=8.69 Hz, 2H), 7.76ꢀ7.80 (m, 1H);
2. General procedure for the synthesis of compounds (9a-l).
200 mg (0.76 mmol) 7a in 14 ml H2O:AcOH (1:1) solvent
was taken with 114 mg (0.84 mmol)
pꢀmethoxy
8|
Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 9 of 12
Organic & Biomolecular Chemistry
View Article Online
DOI: 10.1039/C4OB02277G
8.12ꢀ8.15 (d, J=15.56 Hz, 1H), 8.16ꢀ8.19 (d, J=8.39 Hz, 1H),
1H); 13C NMR (125 MHz, CDCl3): δ 32.81, 56.19, 60.93,
104.77, 106.65, 123.40, 125.51, 126.17, 126.68, 128.65,
128.87, 129.41, 130.03, 130.32, 132.14, 134.35, 135.14,
136.87, 138.95, 144.43, 147.90, 150.03, 153.31, 205.82;
65 IR(KBr): ʋ 2939, 2826, 1693, 1633, 1610, 1580, 1503, 1455,
1357, 1238, 1118, 1008, 968, 836, 768, 702, 650 cmꢀ1; MS–
ESIMS: m/z 440 (M+H)+; HR ESIMS: m/z calcd for
8.24ꢀ8.26 (d, J=8.69 Hz, 2H); 13C NMR (75 MHz, CDCl3): δ
32.75, 124.04, 126.25, 127.38, 128.03, 128.29, 128.81, 129.11,
129.63, 130.12, 130.68, 133.90, 134.57, 134.98, 142.84,
144.93, 147.40, 147.90, 149.06, 153.16, 205.70; IR(KBr): ʋ
3421, 3064, 2925, 2359, 1692, 1595, 1517, 1481, 1443, 1394,
1337, 1207, 1156, 1052, 1025, 967, 870, 839, 765, 749, 656
cmꢀ1; MS–ESIMS: m/z 395 (M+H)+; HR ESIMS: m/z calcd
for C25H19N2O3: 395.1390; found: 395.1397.
5
C28H26NO4: 440.1856; found: 440.1848.
(E)ꢀ1-(2-(4-hydroxy-3-methoxystyryl)-4-phenylquinolin-3-
70 yl) ethanone (9i).
10 (E)ꢀ1-(2-(4-fluorostyryl)-4-phenylquinoline-3-yl) ethanone
o
Yields 82%; mp: 230ꢀ232 C; 1H NMR (300 MHz, CDCl3): δ
(9e).
o
1
Yields 85%; mp: 180ꢀ182 C; H NMR (500 MHz, CDCl3): δ
2.07 (s, 3H), 7.05ꢀ7.09(t, J=8.69 Hz, 2H), 7.10ꢀ7.14 (d, J=15.56
Hz, 1H), 7.37ꢀ7.40 (m, 2H), 7.42ꢀ7.46 (m, 1H),7.51ꢀ7.55 (m,
15 3H), 7.57ꢀ7.61 (m, 3H); 7.72ꢀ7.76 (m, 1H); 8.02ꢀ8.05 (d,
J=15.41 Hz, 1H), 8.15ꢀ8.17 (d, J=8.24 Hz, 1H); 13C NMR (125
MHz, CDCl3): δ 32.80, 115.62, 115.79, 123.76, 125.55,
126.17, 126.76, 128.69, 128.91, 129.21, 129.28, 129.48,
130.06, 130.35, 132.71, 134.43, 135.15, 135.44, 144.46,
20 147.92, 149.98, 205.83; IR(KBr): ʋ 3064, 2927, 2852, 1692,
1632, 1539, 1506, 1483, 1158, 1127, 1052, 970, 822, 766, 706
cmꢀ1; MS–ESIMS: m/z 368 (M+H)+; HR ESIMS: m/z calcd
2.09 (s, 3H), 3.95 (s, 3H), 6.78ꢀ6.86 (m, 1H), 6.88ꢀ6.94 (d,
J=8.30 Hz, 1H), 7.02ꢀ7.07 (d, J=15.48 Hz, 1H), 7.35ꢀ7.45 (m,
5H), 7.51ꢀ7.56 ( m, 3H), 7.70ꢀ7.75 (m, 1H), 7.95ꢀ8.03 (d,
75 J=15.48 Hz, 1H), 8.13ꢀ8.21 (m, 1H), 9.82 (s, 1H); 13C NMR
(75 MHz, CDCl3): δ 29.12, 54.98, 110.04, 114.74, 115.03,
120.72, 121.02, 125.66, 126.01, 128.22, 128.80, 129.52,
129.78, 134.90, 136.50, 143.84, 146.11, 147.21, 149.90,
152.56, 205.14; IR(KBr): ʋ 3420, 2923, 2852, 2359, 1743,
80 1634, 1540, 1506, 1456, 1434, 1383, 1162, 1123, 703, 615 cmꢀ
1; MS–ESIMS: m/z 396 (M+H)+; HR ESIMS: m/z calcd for
C26H22NO3: 396.1594; found: 396.1604.
(E)ꢀ1-(6-nitro-4-phenyl-2-(4-
for C25H19FNO: 368.1445; found: 368.1447.
(E)ꢀ1-(4-phenyl-2-(4-(trifluoromethoxy)styryl)quinolin-3-yl)
25 ethanone (9f).
trifluoromethoxy)styryl)quinolin-3-yl) ethanone (9j).
o
1
85 Yields 90%; mp: 208ꢀ210 C; H NMR (500 MHz, CDCl3): δ
2.08 (s, 3H), 7.14ꢀ7.17 (d, J=15.41 Hz, 1H), 7.24ꢀ7.26 (m,
2H), 7.38ꢀ7.41 ( m, 2H), 7.57ꢀ7.60 (m, 3H), 7.65ꢀ7.67 (d,
J=8.69 Hz, 2H); 8.18ꢀ8.21 (d, J=15.41 Hz, 1H), 8.25ꢀ8.27 (d,
J=9.15 Hz, 1H), 8.49ꢀ8.51 (dd, J=6.86, 2.28 Hz, 1H), 8.56ꢀ
90 8.57 (d, J=2.28 Hz, 1H); 13C NMR (75 MHz, CDCl3): δ 32.49,
121.19, 122.12, 123.29, 123.95, 124.74, 129.28, 129.92,
129.98, 131.23, 133.61, 134.58, 135.80, 137.51, 145.63,
146.56, 149.94, 153.25, 204.69; IR(KBr): ʋ 3395, 3064, 2921,
2851, 1708, 1633, 1617, 1508, 1477, 1444, 1338, 1257, 1214,
95 1052, 967, 844, 764, 732, 669, 642 cmꢀ1; MS–ESIMS: m/z 479
(M+H)+; HR ESIMS: m/z calcd for C26H18F3N2O4: 479.1213;
o
1
Yields 83%; mp: 163ꢀ165 C; H NMR (300 MHz, CDCl3): δ
2.07 (s, 3H), 7.14ꢀ7.21 (d, J=15.86 Hz, 1H), 7.32ꢀ7.35 (m, 1H),
7.37ꢀ7.40 ( m, 3H), 7.46ꢀ7.48 (d, J=7.55 Hz, 1H), 7.49ꢀ7.55 (m,
3H), 7.60ꢀ7.65 (m, 3H); 7.73ꢀ7.78 (m, 1H); 8.04ꢀ8.08 (d,
30 J=15.86 Hz, 1H), 8.12ꢀ8.17 (d, J=8.30 Hz, 1H); 13C NMR (75
MHz, CDCl3): δ 32.78, 121.05, 125.02, 125.65, 126.19,
126.91, 128.43, 128.71, 128.85, 128.95, 129.55, 129.81,
130.06, 130.41, 134.98, 144.57, 147.93, 149.29, 149.74,
205.72; IR(KBr): ʋ 3065, 2922, 2852, 1740, 1703, 1672, 1643,
35 1545, 1506, 1443, 1417, 1394, 1356, 1257, 1210, 1014, 963,
844, 767, 705, 671, 657 cmꢀ1; MS–ESIMS: m/z 434 (M+H)+;
HR ESIMS: m/z calcd for C26H19F3NO2: 434.1362; found:
found: 479.1208.
(E)ꢀ1-(6-nitro-4-phenyl-2-(3,4,5-trimethoxystyryl)quinolin-
3-yl) ethanone (9k).
434.1360.
(E)ꢀ1-(2-(3,5-bis(trifluoromethyl)styryl-4-phenylquinolin-3-
40 yl) ethanone (9g).
o
1
100 Yield 88%; mp: 217ꢀ219 C; H NMR (500 MHz CDCl3 ): δ
2.09 (s, 3H), 3.90 (s, 3H), 3.94 (s, 6H), 6.85 (s, 2H), 7.05ꢀ7.10
(d, J=15.41 Hz, 1H), 7.37ꢀ7.41 (m, 2H), 7.59ꢀ7.61 (m, 3H),
7.13ꢀ7.16 (d, J=15.41 Hz, 1H), 8.23ꢀ8.25 (d, J=7.15 Hz, 1H),
8.48ꢀ8.51 (dd, J=6.71, 2.44Hz, 1H), 8.54ꢀ8.55 (d, J=2.44 Hz,
105 1H); 13C NMR (75 MHz, CDCl3): δ 32.55, 56.20, 60.94,
105.08, 122.21, 123.22, 123.78, 124.54, 129.16, 129.77,
129.89, 131.00, 131.46, 133.58, 139.46, 149.91, 153.37,
153.51, 204.80; IR(KBr): ʋ 3432, 2937, 2837, 2360, 1705,
1630, 1573, 1544, 1525, 1452, 1432, 1340, 1249, 1197, 1005,
110 970, 839, 790, 704, 651 cmꢀ1; MS–ESIMS: m/z 485 (M+H)+;
HR ESIMS: m/z calcd for C28H25N2O6: 485.1707; found:
o
1
Yields 81%; mp: 159ꢀ161 C; H NMR (300 MHz, CDCl3): δ
2.07 (s, 3H), 7.30ꢀ7.36 (d, J=15.48 Hz, 1H), 7.38ꢀ7.41 (m, 2H),
7.46ꢀ7.52 (m, 1H), 7.53ꢀ7.56 (m, 3H), 7.61ꢀ7.63 (dd, J=7.55,
0.75 Hz, 1H); 7.76ꢀ7.81 (m, 2H); 7.99ꢀ8.00 (m, 2H), 8.13ꢀ8.18
45 (d, J=15.67 Hz, 1H), 8.16ꢀ8.20 (d, J=8.49 Hz, 1H); 13C NMR
(75 MHz, CDCl3): δ 32.76, 125.88, 126.29, 127.19, 127.40,
127.67, 129.15, 129.72, 130.09, 130.25, 130.71, 131.89,
132.34, 133.43, 134.51, 135.06, 138.61, 145.00, 147.93,
148.98, 205.65; IR(KBr): ʋ 3428, 3069, 2925, 2854, 1739,
50 1704, 1672, 1610, 1560, 1542, 1451, 1382, 1249, 1183, 1126,
1023, 1009, 951, 892, 773, 764, 682, 659 cmꢀ1; MS–ESIMS:
m/z 486 (M+H)+; HR ESIMS: m/z calcd for C27H18F6NO:
485.1700.
(E)ꢀ1-(2-(4-hydroxy-3-methoxystyryl)-6-nitro-4-
phenylquinolin-3-yl) ethanone (9l).
486.1287; found: 486.1282.
(E)ꢀ1-(4-phenyl-2-(3,4,5-trimethoxystyryl)quinolin-3-yl)
55 ethanone (9h).
o
1
115 Yields 85%; mp: 243ꢀ245 C; H NMR (300 MHz, CDCl3): δ
2.09 (s, 3H), 3.97 (s, 3H), 6.94ꢀ6.97 (d, J=8.12 Hz, 1H), 6.99ꢀ
7.05 (d, J=15.29 Hz, 1H), 7.11ꢀ7.12 (d, J=1.32 Hz, 1H), 7.20ꢀ
7.26 (d, J=6.79, 1.32 Hz, 1H), 7.37ꢀ7.42 (m, 2H), 7.58ꢀ7.60 (
m, 3H), 8.13ꢀ8.19 (d, J=15.48 Hz, 1H), 8.21ꢀ8.24 (d, J=9.25
120 Hz, 1H), 8.46ꢀ8.54 (m, 2H); 13C NMR (75 MHz, DMSOꢀ
o
1
Yield 82%; mp: 172ꢀ174 C; H NMR (300 MHz CDCl3 ): δ
2.09 (s, 3H), 3.89 (s, 3H), 3.93 (s, 6H), 6.84 (s, 2H), 7.10ꢀ7.14
(d, J=15.67 Hz, 1H), 7.38ꢀ7.41 (m, 2H), 7.47 (d, J=7.55 Hz,
1H), 7.52ꢀ7.54 (m, 3H), 7.61 (d, J=7.93 Hz, 1H), 7.74 (t,
60 J=7.55 Hz, 1H), 7.98 (J=15.48 Hz, 1H), 8.16 (d, J=8.49 Hz,
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |9

Organic & Biomolecular Chemistry
Page 10 of 12
View Article Online
DOI: 10.1039/C4OB02277G
d6+CDCl3): δ 31.48, 54.92, 110.06, 114.82, 118.83, 120.96,
121.97, 122.51, 123.24 126.55, 128.01, 128.81, 129.82, 132.60,
134.54, 138.51, 143.94, 146.86, 147.74, 152.80, 203.57;
IR(KBr): ʋ 3290, 3004, 2963, 1666, 1615, 1594, 1543, 1517,
1445, 1422, 1375, 1313, 1263, 1148, 1087, 1035, 968, 907,
Activity Relationship) database.
These compounds were imported into DS 3.5 and converted
60 into 3D structures. Energy minimization was performed for all
of these 3D structures to identify global/local minima by
applying the CHARMm force field. The resulting 3Dstructures
were used to calculate the three principal moments of inertia;
the PMI values are sorted in ascending magnitude, that is, I1, I2,
65 and I3.Normalized PMI ratios (NPR) were calculated by
dividing the two smaller PMI values (I1 and I2) by the largest
PMI value (I3) and generated two characteristic values for each
compound (I1/I3 and I2/I3). These values were plotted against
each other and the resulting graph formed an isosceles triangle
70 that was defined by its three corners, wherein the vector [I1/I3,
I2/I3] was equal to [1,1], [0.5,0.5], and [0,1] (Fig. 1(b) ).
5
762, 709, 657, 645, 629 cmꢀ1;
MS–ESIMS: m/z 441
(M+H)+; HR ESI MS: m/z calcd for C26H21N2O5: 441.1445;
found: 441.1446.
II. X-ray crystallographic study.
10
Xꢀray data for the compounds were collected at room
temperature using a Bruker Smart Apex CCD diffractometer
with graphite monochromated MoK radiation ( =0.71073Å)
with ωꢀscan method34. Preliminary lattice parameters and
orientation matrices were obtained from four sets of
IV. Biology
15 frames.Integration and scaling of intensity data were
accomplished using SAINT program34. The structure was
solved by direct methods using SHELXS9735 and refinement
was carried out by fullꢀmatrix leastꢀsquares technique using
SHELXL97. Anisotropic displacement parameters were
20 included for all nonꢀhydrogen atoms. The Oꢀbound H atom was
located in difference Fourier maps and their positions and
isotropic displacement parameters were refined. All other H
atoms were positioned geometrically and treated as riding on
their parent C atoms [CꢀH = 0.93ꢀ0.97 Å and Uiso(H) =
25 1.5Ueq(C) for methyl H or 1.2Ueq(c) for other H atoms]. The
methyl groups were allowed to rotate but not to tip.
Crystal data for AW80: C26H20N2O5, M = 440.44, colorless
block, 0.18 x 0.16 x 0.07 mm3, monoclinic, space group P21/c
(No. 14), a = 7.1637(7), b = 26.057(3), c = 11.5507(11) Å,
30 = 95.513(2)°, V = 2146.1(4) Å3, Z = 4, Dc = 1.363 g/cm3,
F000 = 920, Bruker SMART APEX CCD areaꢀdetector, MoKλ
radiation, λ = 0.71073 Å, T = 294(2)K, 2 max = 50.0º, 20605
reflections collected, 3783 unique (Rint = 0.0502). Final GooF
= 1.250, R1 = 0.0826, wR2 = 0.1581, R indices based on 3081
35 reflections with I>2σ(I) (refinement on F2), 304 parameters, 0
1. Antimicrobial activity:
(a) Determination of MIC
The antimicrobial activity of the quinoline based
styryl conjugates were determined using well diffusion
method36 (Amsterdam, 1996) against different pathogenic
reference strains which were procured from the Microbial Type
Culture Collection (MTCC), CSIRꢀInstitute of Microbial
80 Technology, Chandigarh, India. The pathogenic reference
strains were seeded on the surface of the media petri plates,
containing MullerꢀHinton agar with 0.1 ml of previously
prepared microbial suspensions individually containing 1.5 ×
108 cfu mlꢀ1 (equal to 0.5 McFarland). Wells of 6.0 mm
85 diameter were prepared in the media plates using a cork borer
and the synthesized quinoline based styryl conjugates at a dose
range of 125 ꢀ 0.9 µg wellꢀ1 were added in each well under
sterile conditions in a laminar air flow chamber. Standard
antibiotic solution of ciprofloxacin and miconazole at a dose
90 range of 125 ꢀ 0.9 µg wellꢀ1 and the well containing methanol
served as positive and negative controls, respectively. The
plates were incubated for 24 h at 37°C for bacterial and 30°C
for Candida albicans and the well containing the least
concentration showing the inhibition zone was considered as
95 the minimum inhibitory concentration. All experiments were
carried out in duplicates and values are represented as mean ±
S.D.
75
restraints,
supplementary Crystallographic data for the structure. These
data can be obtained free of charge at
ꢁ = 0.096 mmꢀ1. CCDC 1023840 contains
www.ccdc.cam.ac.uk/conts/retrieving.html [or from the
40 Cambridge Crystallographic Data Centre (CCDC), 12 Union
Road, Cambridge CB2 1EZ, UK; fax: +44(0) 1223 336 033;
email: deposit@ccdc.cam.ac.uk].
(b) Determination of MBC
Bactericidal assay (NCCLS, 2000) was performed in
100 sterile 2.0 ml microfuge tubes against a panel of pathogenic
bacterial strains,37 including Micrococcus luteus MTCC 2470,
Staphylococcus aureus MTCC 96, Staphylococcus aureus
MLSꢀ16 MTCC 2940, Bacillus subtilis MTCC 121,
Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC
105 2453 and Klebsiella planticola MTCC 530 which were cultured
overnight in Mueller Hinton broth. Serial dilutions of test
compounds were prepared in Mueller Hinton broth with
different concentrations ranging from 0 to125 µg mlꢀ1. To the
test compounds, 100 µl of overnight cultured bacterial
110 suspensions were added to reach a final concentration of 1.5 ×
108 cfu mlꢀ1 (equal to 0.5 McFarland) and incubated at 37 ºC
for 24 h. After 24 h of incubation, the minimum bactericidal
concentration (MBC) was determined by sampling 10 µl of
suspension from the tubes onto Mueller Hinton agar plates and
III.PMI Plot analysis
Materials & Methods:
45
In silico and PMI analysis were carried out on 1100
FDAꢀapproved drugs (randomly taken from our GOSTAR
proprietary database and our compounds. Each molecule was
analyzed for a set of six physiochemical properties by using
online cheminformatics tools, ChemDraw, or manual
50 inspection. The data were collected on an Excel spreadsheet.
These results were used to generate the plot shown in Fig
1(a).The PMI calculations involved aligning each molecule to
the principal moment axes in SYBYL and the normalized PMI
values were calculated by using inꢀhouse software. The 2D
55 chemical structures of the compounds were drawn in Discovery
studio 3.5 (DS 3.5), whereas those of the FDAꢀapproved drugs
were collected from the GOSTAR (GvkbioOnline Structure
10|
Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 11 of 12
Organic & Biomolecular Chemistry
View Article Online
DOI: 10.1039/C4OB02277G
Milbank, R. J. Stevenson, USPat., 2006, 7064117.
10. A. Mahamoud, J. Chevalier, A. DavinꢀRegli, J. Barbe, J. M.
Pages, Curr. Drug Targ., 2006, 7, 843.
65 11. N. Muruganantham, R. Sivakumar, N. Anbalagan, V.
Gunasekaran, J. T. Leonard, Biol. Pharm. Bull., 2004, 27,
1683.
were incubated for 24 h at 37 ºC to observe the growth of test
organisms. MBC is the lowest concentration of compound
required to kill a particular bacterium. All the experiments were
carried in duplicates values are represented as mean ± S.D.
5
12. M. P. Maguire, K. R. Sheets, K. McVety, A. P. Spada, A.
A. Zilberstein, J. Med. Chem., 1994, 37, 2129.
70 13. W. D. Wilson, M. Zhao, S. E. Patterson, R. L. Wydra, L.
Janda, L. Strekowski, R. F. Schinazi, Med. Chem. Res.,
1992, 2, 102.
2. Biofilm inhibition crystal violet assay
The test compounds were screened in sterile 96 well
polystyrene microtiter plates using the modified biofilm
inhibition assay,38 against a panel of pathogenic bacterial
14. L. Strekowski, J. L. Mokrosz, V. A. Honkan, A. Czarny, M.
T. Cegla, S. E. Patterson, R. L. Wydra, R. F. Schinazi,
10 strains including Staphylococcus aureus MTCC 96,
Staphylococcus aureus MLSꢀ16 MTCC 2940 and Klebsiella
planticola MTCC 530, which were cultured overnight in
tryptone soy broth (supplemented with 0.5% glucose). The test
compounds of predetermined concentrations ranging from 0 to
15 250 µg/ml were mixed with the bacterial suspensions having an
initial inoculum concentration of 5×105 CFU/ml. Aliquots of
100 µl were distributed in each well and then incubated at 37
ºC for 24 h under static conditions. The medium was then
discarded and washed with phosphate buffered saline to
20 remove the nonꢀadherent bacteria. Each well of the microtiter
plate was stained with 100 µl of 0.1% crystal violet solution
followed by 30 min incubation at room temperature. Later the
crystal violet solution from the plates was discarded,
thoroughly washed with distilled water for 3 to 4 times and air
25 dried at room temperature. The crystal violet stained biofilm
was solubilised in 95% ethanol (100 µl) and the absorbance
was recorded at 540 nm using TRIAD multimode reader
(Dynex Technologies, Inc, Chantilly, VA, USA). Blank wells
were employed as background check. The inhibition data were
30 interpreted from the doseꢀresponse curves, where IC50 value is
defined as the concentration of inhibitor required to inhibit
50% of biofilm formation under the above assay conditions. All
the experiments were carried out in triplicates and the values
are indicated as mean ± S.D.
75
80
85
90
95
J. Med. Chem., 1991, 34, 1738.
15. G. S. Bisacchi, J. Dumas, In: Macor JE, ed. Annual Reports
in Medicinal Chemistry., Amsterdam Academic Press.
2009, 44, 379.
16. (a) C. Ryu, J. Lee, S. Jeong, J. Nho, Bioorg. Med. Chem.
Lett., 2009, 19, 146.; (b) R. Bhavana, S. Weng, E. Tiekink,
J. Organomet. Chem., 2013,726, 62.
17. S. Gogoi, K. Shekarrao, A. Duarah, T. Bora, S. Gogoi, R.
Boruah, Steroids., 2012, 77, 1438.
18. S. Nagarajan, P. Arjun, N. Raaman, T. Mohan Das,
Carbohydr. Res., 2010, 345, 1988.
19. N. Parmar, H. Barad, B. Pansuriya, S. Teraiya, V. Gupta, R.
Kant, Bioorg. Med. Chem. Lett., 2012, 22, 3816.
20. (a) K. Andries, P. Verhasselt, J. Guillemont, H. W.
Gohlmann, J. M. Neefs, H. Winkler, J. Van Gestel, P.
Timmerman, M. Zhu, E. Lee, Science., 2005, 307, 223.;
(b) Walker, Joseph, Tadena, Nathalie, Wall Street Journal.,
2012, Retrieved.2013ꢀ01ꢀ01.; (c) Edney, Anna, Bloomberg.
2012, Retrieved. 2013ꢀ01ꢀ01.
21. A. Kamal, P. Swapna, R. V. C. R. N. C. Shetti, A. B. Shaik,
M. P. N. Rao, S. Gupta, Eur. J. Med. Chem., 2013, 62, 661.
22. A. Kamal, S. K. Ahmed, K. S. Reddy, M. N. A. Khan,
R. V. C. R. N. C. Shetty, B. Siddhardha, U. S. N. Murthy,
I. A. Khan, M. Kumar, S. Sharma, A. B. Ram,
Bioorg. Med. Chem. Lett., 2007, 17, 5419.
100 23. A. Kamal, R. V. C. R. N. C. Shetti, S. Azeeza, P. Swapna,
M. N. A. Khan, I. A. Khan, S. Sharma, S. T. Abdullah, Eur.
J. Med. Chem., 2011, 46, 893.
24. A. Kamal, J. N. S. R. C. Murty, A. Viswanath, P. Sujitha,
C. G. Kumar, Bioorg. Med. Chem. Lett., 2012, 22, 4891.
105 25. A. Kamal, S. M. A. Hussaini, S. Faazil, Y. Poornachandra,
G. N. Reddy, C. G. Kumar, Bioorg. Med. Chem. Lett.,
2013, 23, 6842.
35
References and Notes
26. (a) S. K. Chervenkov, A. I. Pavlov, S. T. Slavova, Analytical
letters., 1995, 28, 57.; (b) C. Rahime, N. Jan, D. Elena, Thomas J.
1. R. L. Monaghan, J. F. Barrett, Biochem. Pharmacol., 2006,
71, 901.
2. (a) A. Dalhoff, Infection.,1994, 22, S111.; (b) D. Abbanat,
110
J. Müller, Org. Biomol. chem ., 2013, 11, 2597.
27. A. Kamal, A. Mallareddy, P. Suresh, V. L. Nayak,
R.V.C.R.N.C. Shetti, N. S. Rao, J. R. Tamboli, T. B. Shaik,
M.V.P.S. Vishnuwardhan, S. Ramakrishna, Eur. J. Med.
Chem., 2012, 47, 530.
40
M. Macielag, K. Bush, Expert. Opin. Investig. Drugs., 2003,
12, 379.; (c) K. Poole, Curr. Opin. Microbiol., 2001, 4, 500.
(d) C. T. Walsh, G.Wright, Chem. Rev. 2005, 105, 391.
3. M. E. Falagas, A. C. Kastoris, D. E. Karageorgopoulos, P. I.
Rafailidis, Int. J .Antimicrob. Agents., 2009, 34, 111.
115 28. Details are available in experimetal section.
29. (a) GVK Biosciences Pvt. Ltd. proprietary database.;
(b) Stable 3D structures of all of the compounds were used
to calculate their physicochemical properties, such as
molecular weight, number of hydrogenꢀbond donors
45 4. (a) M. C. McManus, Am. J. Health-Syst. Pharm., 1997, 54,
1420.; (b) F. C. Tenover, Am. J. Infect. Control., 2006, 34,
S3.
120
125
130
(HBD), number of hydrogenꢀbond acceptors(HBA), A logP,
log D, and polar surface area (PSA); these values were
calculated by using Discovery studio 3.1, Accelrys. Inc.
30. (a) P. Ertl, B. Rohde, P. Selzer, J. Med. Chem., 2000, 43,
3714.; (b) P. Ertl, Molecular. Drug. Properties.
R. Mannhold (Ed). Wiley-VCH., 2007, 111.
31. SYBYL 8.0. The Tripos Associates., St. Louis. 2008.
32. W. H. Sauer, M. K. Schwartz, J. Chem. Inf. Comput. Sci.,
2003, 43, 987.
5. (a) H. Ceri, M. E. Olson, C. Stremick, R. R. Read, D.
Morck, A. Buret, Clin. J. Microbiol. 1999, 37, 1771.; (b) M.
50
Simoes, M. O. Pereira, M. J. Vieira, Water. Sci. Technol.,
2003, 47, 217.;
(c) R. Slinger, F. Chan, W. Ferris, S. W. Yeung, M. St
Denis, I. Gaboury, S. D. Aaron, Diagn. Microbiol. Infect.
Dis., 2006, 56, 247.
55 6. A. Lilienkampf, J. Mao, B. Wan, Y. Wang, S. G. Franzblau,
A. P. Kozikowski, J. Med.Chem., 2009, 52, 2109.
7. P. Nasveld, S. Kitchener, Trans. R. Soc. Trop. Med. Hyg.,
2005, 99, 2.
33. A. W. Hung, A. Ramek, Y. Wang, T. Kaya, J. A. Wilson,
P. A. Clemonsa, D. W. Younga, Proc. Natl. Acad. Sci.
U.S.A., 2011, 108, 6799.
8. P. A. Leatham, H. A. Bird, V. Wright, D. Seymour, A.
34. SMART & SAINT. Software reference manuals. Versions
6.28a & 5.625, Bruker Analytical Xꢀray Systems Inc.
60
Gordon, Eur. J. Rheumatol. Inflamm., 1983, 6, 209.
9. W. A. Denny, W. R. Wilson, D. C. Ware, G. J. Atwell, J. B.
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |11

Organic & Biomolecular Chemistry
Page 12 of 12
View Article Online
DOI: 10.1039/C4OB02277G
Madison. Wisconsin. U.S.A., 2001.
35. G. M. Sheldrick, SHELXS97 and SHELXL97, Programs
for crystal structure solution and refinement; University of
Gottingen: Germany, 1997.
5
36. D. M.Baltimore, In: Loman, V.(Ed.) D. Amsterdam.
Antibiotics in LaboratoryMedicine., 4th Edition, Williams
and Wilkins, 1996, 52.
37. P. A. Wayne, National Committee for Clinical Laboratory
Standards, Approved standard 5 edi, NCCLS 2000. .
10 38. R. E. Furlani, A. A. Yeagley, C. Melander, Eur. J. Med.
Chem., 2013, 62, 59.
aMedicinal Chemistry and Pharmacology, CSIR-Indian Institute of
Chemical Technology, Uppal Road, Hyderabad 500007, India.
15 bDivision of X-ray Crystallography, CSIR-Indian Institute of Chemical
Technology, Uppal Road, Hyderabad 500007, India.
cGVK Biosciences Pvt. Ltd., Plot No. 79, IDA, Mallapur, Hyderabad
500076
20
25
12
|
Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]