Design, synthesis and antibacterial activities of 5-(pyrazin-2-yl)-4H-1,2, 4-triazole-3-thiol derivatives containing Schiff base formation as FabH inhibitory

Article abstract of DOI:10.1016/j.bmcl.2013.11.079

A series of novel schiff base derivatives (H¹-H²⁰) containing pyrazine and triazole moiety have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of β-ketoacyl-acyl carrier protein synthase III (FabH). These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Bacillus amyloliquefaciens and selected compounds among them were tested for their Escherichia coli FabH inhibitory activity. Based on the biological data, compound H¹⁷ showed the most potent antibacterial activity with MIC values of 0.39-1.56 μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC₅₀ of 5.2 μM, being better than the positive control Kanamycin B with IC₅₀ of 6.3 μM. Furthermore, docking simulation was performed to position compound H¹⁷ into the E. coli FabH active site to determine the probable binding conformation. This study indicated that compound H¹⁷ has demonstrated significant E. coli FabH inhibitory activity as a potential antibacterial agent and provides valuable information for the design of E. coli FabH inhibitors.

Full text of DOI:10.1016/j.bmcl.2013.11.079

Bioorganic & Medicinal Chemistry Letters xxx (2013) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Design, synthesis and antibacterial activities of 5-(pyrazin-2-yl)
-4H-1,2,4-triazole-3-thiol derivatives containing Schiff base
formation as FabH inhibitory
⇑
Fei Zhang, Qing Wen, She-Feng Wang, Baloch Shahla Karim, Yu-Shun Yang, Jia-Jia Liu, Wei-Ming Zhang ,
Hai-Liang Zhu
⇑
Nanjing Institute for the Comprehensive Utilization of Wild Plant, Nanjing 210042, People’s Republic of China
State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
A series of novel schiff base derivatives (H1–H20) containing pyrazine and triazole moiety have been
designed and synthesized, and their biological activities were also evaluated as potential inhibitors of
b-ketoacyl-acyl carrier protein synthase III (FabH). These compounds were assayed for antibacterial
activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and
Bacillus amyloliquefaciens and selected compounds among them were tested for their Escherichia coli FabH
inhibitory activity. Based on the biological data, compound H17 showed the most potent antibacterial
Article history:
Received 4 August 2013
Revised 4 November 2013
Accepted 27 November 2013
Available online xxxx
Keywords:
FabH inhibitor
Antibacterial
activity with MIC values of 0.39–1.56
potent E. coli FabH inhibitory activity with IC50 of 5.2
cin B with IC50 of 6.3
M. Furthermore, docking simulation was performed to position compound H17 into
l
g/mL against the tested bacterial strains and exhibited the most
l
M, being better than the positive control Kanamy-
l
Schiff base
the E. coli FabH active site to determine the probable binding conformation. This study indicated that
compound H17 has demonstrated significant E. coli FabH inhibitory activity as a potential antibacterial
agent and provides valuable information for the design of E. coli FabH inhibitors.
Ó 2013 Published by Elsevier Ltd.
1,2,4-Triazole
Structure–activity relationship
Certain bacterial diseases pose potential threat to human health
and these bacterial diseases yet have not been overcome.1 More
than one-third of the world populations are infected by bacterial
pathogens and nearly two million people per year die from bacte-
rial infections.2 The overuse of various antibiotics has caused resis-
tance in certain bacteria and the human pathogen no longer
response to these clinically used antibiotics.3,4 Therefore, there is
an urgent need for development of new antibacterial agents with
novel target, and the newly designed antibiotics can overcome
the shortcomings of previously developed antibacterial drugs.5,6
To overcome the emerging drug resistance, the discovery of novel
antibiotic chemical scaffolds with new mode of action is crucial for
bacteria survival.
O
CoA
Acetyl-CoA
CO2+CoA-SH
O
O
S
Me
S-Acp
Acetoacetyl-Acp
O
O
FabH
HO
S-Acp
Malonyl-Acp
Figure 1. FabH accomplishes the initial condensation step in FAS II.
The fatty acid biosynthesis (FAS) is an essential metabolic pro-
cess for prokaryotic organisms and it is required for cell viability
and growth, and recently it has attracted the attention to be used
as a target for new antibacterial drugs.7,8 The human fatty acid syn-
thesis occurs via a homodimeric multifunctional enzyme,9,10 while
in bacteria the pathway is consists of various discrete enzymes11
and each one can be considered a supposed target. These features
make the type II FAS pathway a potential target for new antimicro-
bial agents.12
The b-ketoacyl-acyl carrier protein synthase III (FabH) is a key
enzyme in bacterial FAS pathway, which initiates the FAB cycle
by catalyzing the first condensation step between acetyl-CoA and
malonyl-ACP, playing a key regulatory role in the bacterial FAB
cycle (Fig. 1).13 Furthermore, FabH has been confirmed as an essen-
tial for the survival of organism and it exists in a wide number of
important human pathogens.14,15 FabH has also no close homo-
⇑
Corresponding author. Tel./fax: +86 25 83592672.
E-mail addresses: botanyzh@163.com (W.-M. Zhang), zhuhl@nju.edu.cn (H.-L.
Zhu).
0960-894X/$ - see front matter Ó 2013 Published by Elsevier Ltd.
http://dx.doi.org/10.1016/j.bmcl.2013.11.079
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F. Zhang et al. / Bioorg. Med. Chem. Lett. xxx (2013) xxx–xxx
Cl
OH
Br
OH
H
N
Br
N
Cl
N
N
S
HO
11
YKAs3003
OH
Cl
OH
H
N
H
N
N
N
N
N
N
HO
HO
CF3
6
6e
Figure 2. New potential FabH inhibitors: 11 discovered by Zhu et al.; YKAs3003, 6 and 6e discovered by Kim et al.
logue in humans and its selectivity for acetyl-CoA over acyl-ACP
differs from the other condensing enzymes involved in fatty acid
synthesis in bacteria.16,17 In addition, some chemical compounds
from various organisms have been revealed to inhibiting the
FabH,18–22 consequently making FabH as an new target for the
development of new antimicrobial agents.
In addition, the introduction of different heterocyclic com-
pounds to the backbone of carbon chain will affect its biological
activities, which has drawn widespread attention.30,31 Ligands con-
taining a pyrazine ring are generally studied especially
p-donor
properties.32 Pyrazine has been paid wide attention, due to the dia-
zine rings form a significant class of compounds existed in several
natural and synthetic compounds.33 Pyrazine derivatives have
been widely used in the field of pharmaceutical chemistry for the
skeleton of biologically active sites.34
Previously various kinds of compounds were screened by using
structure guided drug design methods.23–26 The compounds con-
taining Schiff base moiety or hydrozone moiety show effective
antimicrobial activity against various bacteria, including inhibitors
of FabH, as reported previously by our laboratory24,25,38 and Kim
Some Schiff base derivatives have been reported as FabH inhib-
itors.6,24,26 In continuation to widen our research on antibacterial
compounds with FabH inhibitory activity, we sought to synthesis
a set of Schiff base derivatives containing pyrazine and triazole
moiety as antibacterial agents. The antimicrobial activity of
these compounds against two Gram-negative bacterial strains
(Escherichia coli and Pseudomonas fluorescence) and three Gram-
positive bacterial strains (Staphylococcus aureus, Bacillus subtilis
and Bacillus amyloliquefaciens) were also determined. Meanwhile,
docking simulations were performed using the X-ray crystallo-
graphic structure of the FabH of E. coli complexed with the most
potent inhibitors6,35 to explore the binding modes of these
compounds at the active site.
and co-workers26,27 Compounds such as (11;24 YKAs3003;27
6
and 6e26) reported as inhibitors of Escherichia coli FabH showed
the most effective antibacterial activity and FabH inhibitory activ-
ity several times in each article that are displayed in Figure 2. As
shown in Figure 2, these compounds always have a Schiff base
moiety (AC@NA) or a hydrazone moiety (ANHAN@CHA) in the
core structures. Moreover, triazole moiety have attracted consider-
able attention because of their particular physical, chemical and
biological activities based on their particular structures and wide
spectrum of biological properties such as antimicrobial activity
against several strains of bacteria.28,29
O
H
N
COOH
N
COOCH3
N
CONHNH2
N
N
N
SK
a
b
c
N
H
S
N
(1)
N
(2)
N
(3)
(4)
d
R5
R4
R3
CHO
N
N
N
SH
R1
(6)
N
N
N
N
R2
SH
N
N
N
R1
e
NH2
R5
R4
N
(5)
R2
R3
Scheme 1. The synthetic routes of compounds H1–H20. Reagents and conditions: (a), methanol, concentrated sulfuric acid, reflux, 12 h; (b) hydrazine hydrate (85%), ethanol,
reflux, 4–5 h; (c) KOH (0.9 N), CS2, ethanol, rt, 8 h; (d) hydrazine hydrate (85%), ethanol, reflux,12 h; (e) ethanol, acetic acid, reflux,4–5 h.
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F. Zhang et al. / Bioorg. Med. Chem. Lett. xxx (2013) xxx–xxx
3
Table 1
mixture was then poured into ice-water in order to obtain the
intermediate 5. Lastly, the synthesis of compounds H1–H20 was
accomplished by reacting 5 with aldehyde 6 in ethanol.6,36 All of
the synthetic compounds presented 1H NMR and ESI-MS spectra
data, which were in full accordance with their depicted structures.
All the synthesized Schiff base derivatives H1–H20 were evalu-
ated for their antimicrobial activities against two Gram-negative
bacterial strains (Escherichia coli and Pseudomonas fluorescence)
and three Gram-positive bacterial strains, (Staphylococcus aureus,
Bacillus subtilis and Bacillus amyloliquefaciens) by the standard
two-fold serial broth dilution method. And the MIC values (mini-
mum inhibitory concentrations) of those compounds against these
bacteria were presented in Table 2. As a control, the standard anti-
bacterial agent kanamycin B was screened under identical condi-
tions. The results revealed the synthetic compounds exhibited
effective antibacterial activities.
Chemical structures of H1–H19
N
N
SH
N
N
N
N
R1
R5
R2
R4
R3
R1
R2
R3
R4
R5
Of all the tested compounds, compound H17 displayed the most
potent activity with MIC values of 0.39, 1.56, 1.56, 0.78 and
H1
H
H
H
H
H
H
F
H
Cl
H
OCH3
H
OCH3
H
H
H
OH
H
H
H
H
H
H
H
H
F
Br
H
F
H
H
H
H
H
H
H
H
H
H
OCH3
OCH3
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H2
H3
0.78
amyloliquefaciens respectively, which was superior to kanamycin
with corresponding MIC values of 3.13, 1.56, 1.56, 3.13,
1.56 g/mL, respectively. Compound 11 in our previous studies
lg/mL against E. coli, P. aeruginosa, S. aureus, B. subtilis and B
H4
Cl
H5
CH3
OCH3
H
H6
B
H7
l
H8
H
Cl
displayed broad-spectrum antimicrobial activity against tested
H9
H
bacterial strains (E. coli, P. aeruginosa, S. aureus and B. subtilis) with
H10
H11
H12
H13
H14
H15
H16
H17
H18
H19
OCH3
H
OCH3
H
OCH3
H
OCH3
OCH3
OCH3
H
MIC values of 0.78–25
l
g/mL.24 YKAs3003 displayed MIC values in
128-256
l
g/mL against various bacteria.27 Compound 6 also dis-
played broad-spectrum antimicrobial activity against bacterial
strains (E. coli, E. faecalis, VREF and S. aureus) with MIC values of
H
NO2
OH
H
4–64
lg /mL; While 6e showed selective antimicrobial activity
H
H
OH
OH
against S. aureus with MIC values of 1–2
l
g/mL, while the MIC val-
ues against other bacterial strains were 32 to >512 l
g/mL.26 Com-
H
H
H
pared to the compounds in previous studies, the compound H17
H
OH
Chemical structures of H20
.
showed much more potent broad-spectrum antibacterial activity
with the MIC values of 0.39–1.56
rial strains.
Then the structure–activity relationships (SAR) studies were
performed to determine how the aldehyde affected the antimicro-
bial activity. Compound H2 without any substituent group on ben-
zene ring showed moderate antimicrobial activity with the mean
lg/mL against the tested bacte-
N
N
SH
N
N
N
N
MIC values of 25, 25, 50, 25 and 50 lg/mL against E. coli, P. aerugin-
osa, S. aureus, B. subtilis and B. amyloliquefaciens, respectively.
We evaluated the effect of introducing different substituent
group(s) at the para-position of benzene ring in H2. According to
the antibacterial data, the introduction of the electron-withdrawing
groups (halogen groups or ANO2) weakened the antimicrobial ef-
fects. For instance, compounds (H1, H3, H4) with halogen group(s)
and H15 with nitro group at the para-position of benzene ring exhib-
ited poor activities with MIC values of both 25 to >50 lg/mL. But
introduction of the electron-donating groups (here it was AOHACH3
or AOCH3) atthe para-positionof benzenering slightlyimprovedthe
antimicrobial effects of compounds (H5, H6, H16) with MIC values of
12.5–50
ring showed the best antibacterial activity in the range of 12.5–
50 g/mL. Among derivatives with electron-withdrawing substitu-
l
g/mL. Among them, H5 with a methyl group on benzene
l
In this study, twenty Schiff base derivatives containing pyrazine
and triazole moiety were synthesized. The synthetic routes of com-
pounds H1–H20 were shown in Scheme 1 and the structure of these
compounds have been shown in Table 1. The synthesis followed
the general pathway. Firstly, esterification of the 2-pyrazine
carboxylic acid 1 with methanol and concentrated sulfuric acid
afforded the corresponding ester 2. Secondly, the pyrazine-2-car-
bohydrazide 3 was obtained by reacting 2 with 85% hydrazine
monohydrate in ethanol. And the hydrazide 3 was stirred with
KOH in absolute methanol and carbon disulfide (CS2) was slowly
ents at the para-position of benzene ring, the potent inhibitory
activity order of compounds with halogen groups was Br > F > Cl
(e.g.,: H1, H3, H4); while derivatives with electron-donating, the po-
tent inhibitory activity order was ACH3 > AOH > AOCH3(e.g.,: H5,
H
16, H6).
Compounds with
a fluorine atom on the ortho-position,
meta-position or para-position of benzene ring exhibited different
degree of inhibitory activity, the potency order was ortho-posi-
tion > para-position > meta-position(e.g.,: H3, H7, H8). Compared
with the inhibitory activity of compounds with hydroxyl group
(e.g.,: H16, H17, H18) and methoxyl group (e.g.,: H6, H13, H14) on
different position respectively, they performed identical results.
added, then compound
4 was precipitated. Thirdly, dried
compound 4 was stirred in concentrated sulfuric acid at 0 °C, the
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F. Zhang et al. / Bioorg. Med. Chem. Lett. xxx (2013) xxx–xxx
Table 2
Antimicrobial activity of the synthesized compounds
Compound
Minimum inhibitory concentrations (
l
g/mL)
Gram-positive
B. subtilis
Gram-negative
E. coli
P. aeruginosa
S. aureus
B. amyloliquefaciens
H1
50.00
25.00
25.00
50.00
12.50
12.50
25.00
25.00
50.00
25.00
6.25
50.00
25.00
>50.00
>50.00
50.00
25.00
50.00
>50.00
>50.00
50.00
12.50
12.50
25.00
50.00
25.00
25.00
1.56
50.00
50.00
50.00
50.00
25.00
50.00
50.00
50.00
50.00
12.50
25.00
12.50
25.00
>50.00
>50.00
50.00
1.56
25.00
25.00
50.00
>50.00
25.00
50.00
50.00
>50.00
>50.00
25.00
3.13
25.00
50.00
50.00
50.00
25.00
25.00
50.00
50.00
>50.00
25.00
6.25
25.00
25.00
50.00
50.00
25.00
0.78
H2
H3
H4
H5
H6
H7
H8
H9
H10
H11
H12
6.25
12.5
6.25
H13
25.00
50.00
25.00
25.00
0.78
50.00
25.00
25.00
3.13
H14
25.00
25.00
12.50
0.39
25.00
12.50
12.50
3.13
H15
H16
H17
H18
25.00
12.50
25.00
1.56
>50.00
25.00
50.00
1.56
50.00
25.00
50.00
1.56
H19
H20
Kanamycin B
Table 3
E. coli FabH inhibitory activities, hemolytic activities and cytotoxicity of the selected
compounds
Compounds
E. coli FabH
IC50 M)
Hemolysis
Cytotoxicity
IC50 M)
(
l
LC30a (mg/mL)
(l
H4
>100.0
27.1
>100.0
45.5
12.8
15.1
22.9
29.3
5.2
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
>10.0
218.1
156.3
205.7
163.3
142.5
169.4
172.7
174.9
131.4
151.2
147.8
139.6
H5
H9
H10
H11
H12
H13
H16
H17
H18
48.3
24.6
6.3
H19
Kanamycin B
a
Lytic concentration 30%.
Compounds H11, H12, H19 with multi-substituted groups showed
Figure 3. Correlation between the antibacterial activity against E. coli and the E. coli
FabH inhibitory activity, y = 1.72198x + 4.04507, R2 = 0.980.
potent antimicrobial activities with MIC values of 3.13–25 lg/mL.
Among the compounds, H11 with three methoxyl group on the
1-position, 3-position and 4-position of benzene ring displayed
best antibacterial activity with MIC values of 3.13-25 lg/mL.
Simultaneously, compound H20 condensed by cinnamaldehyde
Table 4
CDOCKER_INTERACTION_ENERGY of compounds and 1HNJ
displayed an obvious increase in potency with MIC values of
12.5–50
Subsequently, we selected the top 9 compounds (H5, H10–H13
16–H19) and the bottom 2 compounds (H4 and H9) of antibacterial
l
g/mL, compared with H2.
Compounds CDOCKER
INTERACTION ENERGY
Compounds CDOCKER
INTERACTION ENERGY
,
H
D
Gb (kcal/mol)
DGb (kcal/mol)
activity according to their MIC values to examine their E. coli FabH
inhibitory activity and the results were summarized in Table 3. All
the bottom compounds showed poor E. coli FabH inhibitory
activities while most of the top compounds displayed remarkable
E. coli FabH inhibitory activities. Moreover, compound H17 showed
H1
H2
H3
H4
H5
H6
H7
H8
H9
H10
28.20
29.57
27.69
29.27
31.54
27.67
29.15
26.30
29.98
31.39
H11
H12
H13
H14
H15
H16
H17
H18
H19
H20
36.26
32.77
32.03
29.36
27.39
31.51
43.25
30.02
31.76
27.77
the most potent inhibitory activity with IC50 of 5.2
comparable to the positive control Kanamycin B with IC50 of
6.3
M.37 And other tested top compounds displayed moderate
inhibitory activity with IC50 ranging from 12.8 to 48.3 M while
the IC50 of the bottom 2 compounds was all >100 M. The results
lM, which was
l
l
l
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F. Zhang et al. / Bioorg. Med. Chem. Lett. xxx (2013) xxx–xxx
5
Figure 4. (a) 2D molecular docking modeling of compound H17 with 1HNJ. The purple circles showed the amino acids which participated in hydrogen bonding and the p-
cation interactions are shown as orange lines. The green circles showed the amino acids which participated in the Van der Waals interactions. (b) 3D model of the interaction
between compound H17 and 1HNJ bonding site. The one H-bonds (green line) is displayed as dotted line, and the p-cation interactions are shown as orange lines.
demonstrated that H17 had a high binding affinity with E. coli FabH,
which was consistent with the potent antibacterial activity of H17
model of compound H17 with 1HNJ is depicted in Figure 4. In the
binding model of H17, H17 is nicely bound to the 1HNJ via hydrogen
bond with ARG A: 36 (angle OÁÁÁHAN = 140.24°, distance = 1.7 Å),
and Pi–Pi interactions (distance = 4.7 Å) is formed by TRP A:32
with pyrazine ring, which strengthened the binding affinity, lead-
ing to the increased antimicrobial activity of the compound. The
binding model of H17 inferred that the introduction of pyrazine
moiety made the ligand easier to combine with FabH, compared
with the reported compounds.6,39 Hence, high binding affinities
led to potent antimicrobial activity and the attempt to obtain
new potential antibacterial FabH inhibitors had been verified with
the expected results.
To conclude, a series of schiff base derivatives containing pyra-
zine and triazole moiety were designed, prepared and evaluated
for their antibacterial activity against E. coli, P. aeruginosa, S. aureus,
B. subtilis and B. amyloliquefaciens. Some synthetic compounds
showed potent antibacterial and E. coli FabH inhibitory activities
with compound H17 showed the most effective antibacterial activ-
ity with MIC values of 0.39–1.56 mg/mL against the tested bacte-
rial strains and revealed the most potent E. coli FabH inhibitory
.
One of the major obstacles to the clinical use of many com-
pounds with potent antibacterial activities, however, is their ability
to lesion mammalian cell that causes high hemolytic and cytotoxic
activity to the host organism. Hemolytic activity, as a measure of
cytotoxicity and model for mammalian cells, is conventionally
used due to the fragility of red blood cells generally. But occasion-
ally compounds which show low hemolytic activities have the
fearful cytotoxicity against mammalian cells. Therefore, the hemo-
lysis and cytotoxicity assays were both tested. Then we tested their
cytotoxic activity on a mouse embryonic fibroblast cell line (NIH-
3T3) using the MTT assay and their hemolytic activity to prove
the potency of the compounds.26
The pharmacological results of these compounds were summa-
rized in Table 3. It showed that the selected compounds possessed
low hemolytic activities. Based on the date, it demonstrated that
the compounds with potent inhibitory activity were low toxic.
The analysis between the antibacterial activity against E. coli
and the E. coli FabH inhibitory activity of the top 9 compounds
(H5, H10–H13, H16–H19) indicated that there was a moderate corre-
lation between FabH inhibition and inhibition of E. coli cellular pro-
liferation, as confirmed in Figure 3, with a correlation coefficient
value (R square) of 0.980.
activity with IC50 of 5.2 lM. And the cytotoxicity test
demonstrated that the selected compounds possessed low cyto-
toxic activities. Meanwhile, the structure-activity relationships
and molecular modeling study offered further insight into interac-
tions between the receptor and its ligands. The binding model of
H17 inferred that the introduction of pyrazine moiety made the li-
gand easier to combine with FabH, compared with the reported
compounds. The structure can be introduced into some nature
antibacterial compounds as the potent inhibitor in the future
study.
The results of E. coli FabH inhibitory activities were correspond-
ing to the structure-activity relationships (SAR) of the antibacterial
activities which were tested. This indicated that the potent anti-
bacterial activities of the synthetic compounds were probably re-
lated to their FabH inhibitory activities.
The molecular docking of the synthetic Schiff base derivatives
and E. coli FabH was performed on the binding model based on
the E. coli FabH-CoA complex structure (1HNJ. pdb)38 by using
the Discovery Stutio (version 3.1), to gaining the better
understanding on the potency of compounds and guide further
SAR studies. The docking calculation of the compounds was de-
picted in Table 4. It demonstrated that the compounds had good
binding affinity to FabH and the results of EDOCKER_INTERAC-
TION_ENERGY almost have the same trend with the structure
activity relationships of antibacterial activities, which further
proved the correlation between the antibacterial activities and
E. coli FabH inhibitory activities of the compounds.
In summary, this study shows that compound H17 has demon-
strated significant E. coli FabH inhibitory activity as a potential
antibacterial agent and provides valuable information for the de-
sign of E. coli FabH inhibitors.
Acknowledgment
The work was financed by Natural Science Foundation of China
(No. J1103512).
Supplementary data
Compounds, especially compound H17 with the most effective
inhibitory activity displayed the maximum data, and illustrated
that it was most easy to combine with E. coli FabH. The binding
Supplementary data associated with this article can be found, in
theonline version, at http://dx.doi.org/10.1016/j.bmcl.2013.11.079.
Please cite this article in press as: Zhang, F.; et al. Bioorg. Med. Chem. Lett. (2013), http://dx.doi.org/10.1016/j.bmcl.2013.11.079

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F. Zhang et al. / Bioorg. Med. Chem. Lett. xxx (2013) xxx–xxx
21. Li, Z.; Huang, Y.; Ge, J.; Fan, H.; Zhou, X.; Li, S.; Bartlam, M.; Wang, H.; Rao, Z. J.
References and notes
Mol. Biol. 2007, 371, 1075.
22. Oefner, C.; Schulz, H.; D’Arcy, A.; Dale, G. E. Acta Crystallogr. Sect. D: Biol.
Crystallogr. D 2006, 62, 613.
23. Lee, P. J.; Bhonsle, J. B.; Gaona, H. W.; Huddler, D. P.; Heady, T. N.; Deitrick, M.
K.; Bhattacharjee, A.; McCalmont, W. F.; Gerena, L.; Lopez-Sanchez, M.; Roncal,
N. E.; Hudson, T. H.; Johnson, J. D.; Prigge, S. T.; Waters, N. C. J. Med. Chem. 2009,
52, 952.
24. Lv, P. C.; Wang, K. R.; Yang, Y.; Mao, W. J.; Chen, J.; Xiong, J.; Zhu, H. L. Bioorg.
Med. Chem. Lett. 2009, 19, 6750.
25. Lv, P. C.; Sun, J.; Luo, Y.; Yang, Y.; Zhu, H. L. Bioorg. Med. Chem. Lett. 2010, 20,
4657.
26. Lee, J. Y.; Jeong, K. W.; Shin, S.; Lee, J. U.; Kim, Y. Eur. J. Med. Chem. 2012, 47,
261.
27. Lee, J. Y.; Jeong, K. W.; Lee, J. U.; Kang, D. I.; Kim, Y. Bioorg. Med. Chem. 2009, 17,
1506.
28. Khalil, Nasser S. A. M. Eur. J. Med. Chem. 2007, 42, 1193.
29. Rasrasl, A. J. M. Eur J. Med. Chem. 2010, 45, 2307.
30. Zhao, Y.; Ouyang, G. P.; Xu, W. M.; Jin, L. H.; Yuan, K. Chin. J. Org. Chem. 2011,
2010, 30.
31. Yang, Y. S.; Zhang, F.; Gao, C.; Zhang, Y. B.; Wang, X. L.; Gong, H. B.; Zhu, H. L.
Bioorg. Med. Chem. Lett. 2012, 22, 4619.
1. Pérez-Castillo, Yunierkis; Cabrera-Pérez, Miguel Ángel; Ann Nowé J. Comput.
Aided. Mol. Des. 2011, 25, 371.
2. Monaghan, R. L.; Barrett, J. F. Biochem. Pharmacol. 2006, 71, 901.
3. Wang, J. et al Nature 2006, 441, 358.
4. Leeb, M. Nature 2004, 431, 892.
5. Khalafi-Nezhad, A.; Rad, M. N. S.; Mohabatkar, H.; Asrari, Z.; Hemmateenejad, B.
Bioorg. Med. Chem. 1931, 2005, 13.
6. Wang, X. L.; Zhang, Y. B.; Tang, J. F.; Yang, Y. S.; Chen, R. Q.; Zhang, F.; Zhu, H. L.
Eur. J. Med. Chem. 2012, 57, 373.
7. Heath, R. J.; Rock, C. O. Bioorg. Med. Chem. 1995, 270, 44.
8. Heath, R. J.; Rock, C. O. Curr. Opin. Investig. Drugs 2004, 5, 146.
9. Jayakumar, A.; Tai, M. H.; Huang, W. Y.; al-Feel, W.; Hsu, M.; Abu-Elheiga, L.;
Chirala, S. S.; Wakil, S. J. Proc. Natl. Acad. Sci. U.S.A. 1995, 92, 8695.
10. Jayakumar, A.; Huang, W. Y.; Raetz, B.; Chirala, S. S.; Wakil, S. J. Proc. Natl. Acad.
Sci. U.S.A. 1996, 93, 14509.
11. Alhamadsheh, M. M.; Musayev, F.; Komissarov, A. A.; Sachdeva, S.; Wright, H.
T.; Scarsdale, N.; Florova, G.; Florova, G.; Reynolds, K. A. Chem. Biol. 2007, 14,
513.
12. Li, H. Q.; Luo, Y.; Zhu, H. L. Bioorg. Med. Chem. 2011, 19, 4454.
13. Li, Z. L.; Li, Q. S.; Zhang, H. J.; Hu, Y.; Zhu, D. D.; Zhu, H. L. Bioorg. Med. Chem.
2011, 19, 4413.
14. Lu, Y. J.; Zhang, Y. M.; Rock, C. O. Biochem. Cell Biol. 2004, 82, 145.
15. Tsay, J. T.; Oh, W.; Larson, T. J.; Jackowski, S.; Rock, C. O. J. Biol. Chem. 1992, 267,
6807.
16. Campbell, J. W.; Cronan, J. E. J. Annu. Rev. Microbiol. 2001, 55, 305.
17. Zhang, Y. M.; White, S. W.; Rock, C. O. J. Biol. Chem. 2006, 281, 17541.
18. Freundlich, J. S.; Wang, F.; Tsa, H. C.; Kuo, M.; Shieh, H. M.; Anderson, J. W.;
Nkrumah, L. J.; Valderramos, J. C.; Yu, M.; Kumar, T. R. S.; Valderramos, S. G.;
Jacobs, W. R., Jr; Schiehser, G. A.; Jacobus, D. P.; Fidock, D. A.; Sacchettini, J. C. J.
Biol. Chem. 2007, 282, 25436.
19. Muench, S. P.; Prigge, S. T.; McLeod, R.; Rafferty, J. B.; Kirisits, M. J.; Roberts, E.
J.; Mui, C. W.; Rice, D. W. Acta Crystallogr. Sect. D: Biol. Crystallogr. 2007, 63, 328.
20. Dias, M. V. B.; Vasconcelos, I. B.; Prado, A. M. X.; Fadel, V.; Basso, L. A.; de
Azevedo, W. F.; Santos, D. S. Biology 2007, 159, 369.
32. Singh, A. K.; Kumar, P.; Yadav, M.; Pandey, D. S. J. Organomet. Chem. 2010, 695,
567.
33. Zhao, X. H.; Liu, S. S.; Li, Y. Z.; Chen, M. D. Spectrochim. Acta. 2010, 75, 794.
34. Janin, Yves L. Bioorg. Med. Chem. 2007, 15, 2479.
35. Knight, R. L.; Meier, D.; Oliver, K.; Meissner, J. W. G.; Owen, D. A.; Thomas, E. J.;
Tremayne, N.; Williams, S. C. Bioorg. Med. Chem. Lett. 2008, 18, 147.
36. Zhang, Y. B.; Wang, X. L.; Liu, W.; Yang, Y. S.; Tang, J. F.; Zhu, H. L. Bioorg. Med.
Chem. 2012, 20, 6356.
37. He, X.; Anne, M. R.; Umesh, R. D.; Glen, E. K.; Kevin, A. R. Antimicrob. Agents
Chemother. 2004, 48, 3093.
38. Qiu, X.; Janson, C. A.; Smith, W. W.; Head, M.; Lonsdale, J.; Konstantinidis, A. K.
J. Mol. Biol. 2001, 307, 341.
39. Li, H. Q.; Luo, Y.; Lv, P. C.; Shi, L.; Liu, C. H.; Zhu, H. L. Bioorg. Med. Chem. Lett.
2010, 20, 2025.
Please cite this article in press as: Zhang, F.; et al. Bioorg. Med. Chem. Lett. (2013), http://dx.doi.org/10.1016/j.bmcl.2013.11.079