Synthesis, antimicrobial and cytotoxic activities, and molecular docking studies of N-arylsulfonylindoles containing an aminoguanidine, a semicarbazide, and a thiosemicarbazide moiety

Article abstract of DOI:10.1016/j.ejmech.2019.01.038

Thirty-six N-arylsulfonyl-3-substituted indoles were designed and synthesized by combining the N-arylsulfonylindoles with aminoguanidine, semicarbazide, and thiosemicarbazide, respectively. Their antibacterial activities were screened, and cytotoxic activities were evaluated. The results showed that aminoguanidines (6) exhibited much better antibacterial activity than semicarbazides (7) and thiosemicarbazides (8). Most compounds in series 6 showed potent inhibitory activity against the tested bacterial strains, including multidrug-resistant strains, with MIC values in the range of 1.08–23.46 μM. The cytotoxic activity of the compounds 6c, 6d, 6h, 6j, 6k and 6l was assessed in two human cancer cell lines A590 and SGC7901, and one human normal cell line HEK 293T. The results indicated that compounds selected exhibited excellent activity against the tested cancer cells with IC₅₀ values in the range of 1.51–15.12 μM suggesting the potential of them as new antibacterial and anticancer agents. What's more, the results of resistance study revealed that resistance of the tested bacteria toward 6d is not easily developed. Molecular docking studies revealed that the aminoguanidine and arylsulfonylindole moieties played a significant role in binding the target site of E. coli FabH-CoA receptor.

Full text of DOI:10.1016/j.ejmech.2019.01.038

Accepted Manuscript
Synthesis, antimicrobial and cytotoxic activities, and molecular docking studies
of N-arylsulfonylindoles containing an aminoguanidine, a semicarbazide, and a
thiosemicarbazide moiety
Mingxia Song, Shiben Wang, Zhiyang Fu, Shengchao Zhou, Huabin Cheng, Zhuo
Liang, Zengtao Wang, Xianqing Deng
PII:
S0223-5234(19)30048-0
DOI:
https://doi.org/10.1016/j.ejmech.2019.01.038
EJMECH 11045
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 15 July 2018
Revised Date: 19 October 2018
Accepted Date: 15 January 2019
Please cite this article as: M. Song, S. Wang, Z. Fu, S. Zhou, H. Cheng, Z. Liang, Z. Wang, X. Deng,
Synthesis, antimicrobial and cytotoxic activities, and molecular docking studies of N-arylsulfonylindoles
containing an aminoguanidine, a semicarbazide, and a thiosemicarbazide moiety, European Journal of
Medicinal Chemistry (2019), doi: https://doi.org/10.1016/j.ejmech.2019.01.038.
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ACCEPTED MANUSCRIPT
Graphical abstract
O
S
N
O
H
N
E. coli FabH-CoA
H
NH2
HCl
NH
Br
Br
N
N
MIC = 1.12 uM
MIC = 0.56 uM
(methicillin-resistant S. aureus)
(multidrug-resistant E. coli )

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Synthesis, antimicrobial and cytotoxic activities, and molecular docking studies
of N-arylsulfonylindoles containing an aminoguanidine, a semicarbazide, and a
thiosemicarbazide moiety
Mingxia Song a, Shiben Wang b, Zhiyang Fu a, Shengchao Zhou a, Huabin Cheng a, Zhuo Liang a,
Zengtao Wang c, Xianqing Deng a, *
a Basic Medical and Pharmacy College, Jinggangshan University, Ji’an, 343009, Jiangxi, China;
b School of Pharmacy; Liaocheng University; LiaoCheng, 252059, Shandong, China
c
College of pharmacy, Jiangxi University of Traditional Chinese Medicine, Nanchang, 330004,
Jiangxi, China
Abstract
Thirty-six N-arylsulfonyl-3-substituted indoles were designed and synthesized by combining
the N-arylsulfonylindoles with aminoguanidine, semicarbazide, and thiosemicarbazide,
respectively. Their antibacterial activities were screened, and cytotoxic activities were evaluated.
The results showed that aminoguanidines (6) exhibited much better antibacterial activity than
semicarbazide (7) and thiosemicarbazides (8). Most compounds in series 6 showed potent
inhibitory activity against the tested bacterial strains, including multidrug-resistant strains, with
MIC values in the range of 1.08–23.46 µM. The cytotoxic activity of the compounds 6c, 6d, 6h, 6j,
6k and 6l was assessed in two human cancer cell lines A590 and SGC7901, and one human
normal cell line HEK 293T. The results indicated that compounds selected exhibited excellent
activity against the tested cancer cells with IC50 values in the range of 1.51-15.12 µM suggesting
the potential of them as new antibacterial and anticancer agents. What’s more, the results of
resistance study revealed that resistance of the tested bacteria toward 6d is not easily developed.
Molecular docking studies revealed that the aminoguanidine and arylsulfonylindole moieties
played a significant role in binding the target site of E. coli FabH-CoA receptor.
Keywords: N-arylsulfonylindole; aminoguanidine; antibacterial activity; cytotoxic activities;
docking
1. Introduction
The search for new antibacterial drugs is an urgent and attractive goal for medicinal chemists
because of the increasing antibacterial resistance [1]. Drug-resistant bacteria, such as
methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE),
multi-drug resistant Escherichia coli, and multi-drug resistant Pseudomonas aeruginosa, cause
lethal diseases and great difficulties in the treatment of community-acquired and nosocomial
infections [2–5], which severely threaten global public health and result in high economic costs
[6]. The main reason for this worldwide problem is the widespread use of broad-spectrum
antibiotics, anticancer drugs, and anti-HIV drugs, which facilitate the evolution of resistance [7].
A possible solution for this problem is the responsible use of existing drugs, and the search for
new antibacterial drugs with a new mechanism of action and/or with the ability to overcome drug
resistance.
Indole, an intercellular signaling molecule, regulates various aspects of bacterial physiology,
including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence

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[8]. A number of indole derivatives, including auxin phytohormone indole-3-acetic acid (IAA) and
neurotransmitters such as serotonin, have important cellular functions [9, 10]. Thus far, indoles
have been reported to exhibit important physiological functions and potent pharmacological
activities, including anti-inflammatory and antioxidant [11], antineoplastic [12-14], antimicrobial
[15, 16], antiviral [14, 17, 18], anti-HIV activity [19], and anti-cancer [20]. N-arylsulfonylindoles,
an indole derivative, have received increasing attention in the field of chemical drug research as
5-HT6 receptor antagonists [21], anti-AIDS agents [22], and antifungal agents [23]. Based on the
antibacterial property of sulfonamides, we investigated a series of N-arylsulfonylindoles as
antibacterial agents in our previous work (Figure 1). Their marked inhibitory activity against
gram-positive bacteria (including multidrug-resistant clinical isolates) confirmed our hypothesis
that N-arylsulfonylindole is a potent skeleton to develop new antibacterial drugs [24].
Figure 1. Structure of N-arylsulfonylindoles and hydrazone-containing antibiotics
(thioacetazone, furacin, and furazolidone)
Chemical compounds having azomethine –NHN=CH moiety (hydrazone) represent an
important class for the development of antimicrobial agents [25, 26]. As representatives of clinical
drugs containing the hydrazone moiety, thioacetazone, furacin, and furazolidone (Figure 1) play
an important role in the treatment of infections [27-29]. Hydrazone compounds can easily form
multiple hydrogen bonds with the proteins of microorganisms to increase the binding force of the
receptor. Therefore, hydrazone compounds have been extensively researched to find new
antimicrobial agents. Recently, this scaffold was found to have important therapeutic targets on
β-ketoacyl-acyl carrier protein synthase III (FabH) enzyme [30]. FabH has an important role in the
catalysis of branched-chain fatty acids, both in gram-positive and gram-negative bacteria; however,
there are no significant homologous proteins in humans [31].
Based on these observations, and as part of our ongoing program aimed at the discovery and
development of new antimicrobial molecules, in this work, three series of
N-arylsulfonyl-3-substituted indoles 6a-6l, 7a-7l, and 8a-8l were designed. The target compounds
were prepared by combining the N-arylsulfonylindoles with an aminoguanidine, a semicarbazide,
and a thiosemicarbazide moiety, respectively. Their antibacterial activities were screened against
gram-positive and gram-negative bacteria, and molecular docking of FabH was performed to

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verify the action target and understand the binding pattern. Considering the reported anticancer
activity of numerous compounds containing guanidine moiety [32, 33], the anticancer activity of
aminoguanidines (6) was also evaluated against two cancer cell strains (A590 cells and SGC7901
cells).
2. Result and discussion
2.1. Chemistry
The synthetic route to prepare a new class of N-arylsulfonylindole-linked aminoguanidines,
semicarbazides, and thiosemicarbazides from indoles (1a, 1b) and benzenesulfonyl chlorides (2a,
2b) is depicted in Scheme 2. In one route, the reaction of 1 with 2 in the presence of sodium
hydroxide and benzyltriethylammonium chloride in dry dichloromethane produced
N-benzenesulfonylindoles (3a-3d). Then compounds 5a-5h were prepared by the acetylization
and propionylation of 3a-3d using acetyl chloride and propionic anhydride, respectively, in the
presence of AlCl3. In another route, under Vilsmeier-Haack (DMF-POCl3) conditions, compounds
1a and 1b were transformed into corresponding 3-carboxaldehyde functionalized indoles (4a, 4b),
which then reacted with benzenesulfonyl chlorides (2a, 2b) to afford compounds 5i-5l. Finally, the
condensation of 5a-5l with aminoguanidines, semicarbazides, and thiosemicarbazides, produced
the target compounds 6a-6l, 7a-7l, and 8a-8l, respectively. The structures of the target compounds
were well characterized by 1H-NMR, 13C-NMR, and high-resolution mass spectrometry.
Scheme 1. The synthesis route of compounds 6a-6l, 7a-7l, and 8a-8l. Reagents and Conditions: (a)
NaOH/TEBA; (b) POCl3/DMF; (c) Aminoguanidine hydrochloride for series of 6a-6l/
semicarbazide hydrochloride for series of 7a-7l/thiosemicarbazide for series of 8a-8l.

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2.2. Antimicrobial activity
All of the target compounds (6a-6l, 7a-7l, and 8a-8l) were evaluated for their in vitro
anti-bacterial activity using a serial dilution method to obtain the minimum inhibitory
concentration (MIC) against six gram-positive strains (S. aureus (CMCC(B) 26003 and CMCC
25923, S. pyogenes CMCC 32067, E. faecalis CMCC 29212, and B. subtilis CMCC 63501), four
gram-negative strains (E. coli (CMCC 25922 and CMCC 44568) and P. aeruginosa (CMCC 27853
and CMCC 10104)) as well as two methicillin-resistant clinical isolates (S. aureus ATCC 43300
and ATCC 33591) and two multidrug-resistant gram-negative strains (E. coli ATCC BAA-196 and P.
aeruginosa ATCC BAA-2111). Gatifloxacin, moxifloxacin, norfloxacin, oxacillin, and penicillin
were used as positive control drugs.
<Insert Table 1>
First, compounds 6-8 were screened for their activity against six gram-positive strains and four
gram-negative strains. Initial screening results described as MIC values are presented in Table 1.
The results showed that gram-positive bacteria were more susceptible to tested compounds than
gram-negative ones. The aminoguanidines (6) exhibited greater activity than semicarbazide (7),
and thiosemicarbazides (8). Among aminoguanidines (6), most of the tested compounds showed
potent inhibitory activity against the selected bacterial strains, especially S. aureus CMCC(B)
26003 and 25923, S. pneumonia CMCC 31968, B. subtilis CMCC 63501, and E. coli CMCC
44568 with MIC values in the range of 1.08–23.46 µM. Among them, compounds 6a, 6f, and 6h
showed the highest activity against S. pneumonia CMCC 31968 with MICs of 1.40, 1.12 and 1.08
µM, while compounds 6d and 6j showed the best activity against E. coli CMCC 44568 with MICs
of 1.12 and 1.19 µM respectively. P. aeruginosa isolates have a low antibiotic susceptibility and
are resistant to many common first-line antibiotics. It is worth mentioning that, in this study, some
compounds such as 6a, 6c, 6e, and 6i-6k exhibited good inhibition activity against two P.
aeruginosa strains (CMCC 27853 and CMCC 10104). For the series of semicarbazide (7) and
thiosemicarbazides (8), most of the compounds showed no inhibition activity against the selected
bacterial strains in the range of 267.78–359.55 µM, except 7b, 7d, 7g, 7i-7l, 8a, 8c, 8e, and 8f,
which exhibited moderate activity against some gram-positive strains.
<Insert Table 2>
In the following trials, six compounds (6c, 6d, 6h, 6j, 6k, and 6l) were chosen to evaluate their
inhibitory activity against two methicillin-resistant clinical isolates (S. aureus ATCC 43300 and
ATCC 33591) and two multidrug-resistant gram-negative strains (E. coli ATCC BAA-196 and P.
aeruginosa ATCC BAA-2111) based on their excellent performance in the preliminary trials. As
shown in Table 2, all the tested compounds had excellent inhibitory activities against the two

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methicillin-resistant clinical isolates, with MICs in the range of 1.12-5.63 µM. They also exhibited
moderate activity against the multi-drug resistant E. coli ATCC BAA-196, with MICs in the range
of 0.56–11.27 µM. On the contrary, no inhibitory activity was noted against P. aeruginosa ATCC
BAA-2111 at concentrations below 69.41–86.72 µM except for compound 6k, with an MIC of
11.27 µM. In this trial, compound 6d was the most potent one, with an MIC of 1.12 µM and 0.56
µM against S. aureus ATCC 43300 and E. coli ATCC BAA-196, respectively; it also showed
superior activity compared with that of gatifloxacin, moxiflocaxin, norfloxacin, oxacillin, and
penicillin.
Figure 2. Propensity of the development of bacterial resistance toward compound 6d and
norfloxacin. (A for S. aureus; B for E. coli).
Bacterial resistance against most antibiotics is a major threat to public health [34]. Thus, the
propensity of compounds to inhibit bacterial resistance is an important property. The ability of 6d
to oppose the development of resistance against S. aureus and E. coli was tested. Norfloxacin was
selected as positive controls. Resistance is usually defined as a > 4-fold increase from the original
MIC value [35]. No change in the MIC of compound 6d presented in the test, indicating that
exposure of the S. aureus and E. coli to it did not lead to the development of bacterial resistance
over 18 generations. In contrast, norfloxacin showed 32-fold and 16-fold increases in the MIC
values for the S. aureus and E. coli, respectively (Fig. 2). The results revealed that resistance of
the tested bacteria toward 6d is not easily developed.
Figure 3. Interactions of compound 6d with E. coli FabH (A for 2D model; B for 3D model).

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FabH receptor (also called β-ketoacyl-acyl carrier protein synthase III receptor) is a
condensing enzyme that plays key roles in fatty acid biosynthesis [36]. It has been an essential
target for novel antibacterial drug design [37, 38]. In this study, to illustrate the probable
molecular interactions between the antimicrobial compounds and receptor (PDB ID: 1HNJ) [39],
the molecular docking of representative 6d was developed using Discovery Studio 4.5 version (DS
4.5, Fig. 3). The binding site was defined based on the volume occupied by the bound ligand in
“Define and Edit Binding site” tools of DS 4.5. The first validation of docking protocol was
performed by redocking of the co-crystallized ligand MLC to the active site of FabH protein (Fig.
4A). The RMSD value was used for evaluating the accuracy of the docking protocol, which was
calculated by the difference between original and redocking poses using the DS 4.5 software. The
results suggested that the redocked ligand completely superimposed on the co-crystallized one
(Fig. 4B) with a low RMSD value of 0.722 Ǻ.
Figure 4. (A) The co-crystallized MLC in 3D ligand-protein complex (PDB: 1HNJ). (B)
Redocking of the co-crystallized MLC yielded RMSD of 0.722 Ǻ.
According to the molecular docking analysis, 6d showed a -CDOCKER_energy value of 22.65,
reflecting that 6d could bind with the active site well. As shown in Fig. 3, the key residues
including GLU211, GLY209, ASN210, Val212, ASN247, PHE213, ILE250, Met207, ILE156, and
ALA246, involved in the recognition for 6d in the active site of E. coli FabH. The C=N group of
compound 6d as an H-bond acceptor was involved in the interaction with the hydroxy group of
Asn210, while the guanidine group was responsible to form a hydrogen bond and an electrostatic
interaction with Glu211. In addition to the above, the arylsulfonylindole showed various
interactions with some critical amino acid residues (Gly209, Asn247, Phe213, Val212, Met207,
Ile156, Ile250, and Ala246) via aromatic stacking interaction, hydrogen bonding, and hydrophobic
force interaction. These docking results indicated that aminoguanidine and arylsulfonylindole
moieties played a significant role in binding to the target site of E. coli FabH-CoA receptor.

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Figure 5. Interactions of compound SB-418011 with E. coli FabH (A for 2D model; B for 3D
model).
For comparison, the potent FabH inhibitor SB418011 was performed by a molecular docking
(Fig. 5) [40]. The SB418011 showed a similar -CDOCKER_energy value (26.47) to compare with
6d. The common residue GLY209 was responsible for a Pi-sigma stacked interaction with the
indole skeleton of SB418011. In addition, there are three alkyl interactions with the hydrophobic
residues of the inner cavity (ARG151, TRP32 and MET207). Specifically, the carboxylic acid
group of SB418011 formed a strong hydrogen bond and attractive charge interaction. These
docking study results indicated a small difference between the binding modes of 6d and
SB418011.
<Insert Table 3>
<Insert Table 4>
2.3. Cytotoxic activity
Compounds 6c, 6d, 6h, 6j, 6k, and 6l were also chosen to evaluate their cytotoxic activity
against two human cancer cell lines: A590 and SGC7901 and one human normal cell lines: HEK
293T. The IC50 values of the tested compounds are shown in Table 3. Interestingly, all the tested
compounds showed excellent activity against the investigated cancer cells with an IC50 range of
1.51–15.12 µM. The highest activity against A590 cells was exhibited by compound 6h (IC50
=
2.33 µM), followed by compound 6c (IC50 = 2.68 µM). The highest activity against SGC7901 was
exhibited by compound 6d (IC50 = 1.51 µM); compounds 6c and 6k (IC50 = 2.38, 2.12 µM,
respectively) also exhibited good activities. Compounds 6c, 6d, 6h, 6j, 6k, and 6l showed IC50
values in the range of 52.99–86.66 µM against the normal cell line HEK 293T, and the results
indicated that these compounds have non-toxicity in normal cells in comparison to cancer cells,
suggesting a potential for a good therapeutic index as anticancer drugs. Additionally, their

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selectivity index (SI) was calculated using the cytotoxicity against HEK 293T and their
antimicrobial activity (Table 4). Due to the low toxicity and high antibacterial activity, most of
presented compounds showed acceptable SI for all bacterial strains. Compound 6d exhibited the
highest SI value of 100.70 for Multi-drug resistant Escherichia coli ATCC BAA-196.
3. Conclusion
In the present work, a series of novel N-arylsulfonylindoles containing an aminoguanidine, a
semicarbazide, or a thiosemicarbazide moiety were synthesized and characterized. These
compounds were screened for antimicrobial and anticancer activities. Gram-positive bacteria were
more susceptible towards these tested compounds than gram-negative ones. The aminoguanidine
derivatives (6), having a greater polarity and more hydrogen bonding, exhibited greater activity
than semicarbazide and thiosemicarbazide derivatives (7 and 8). Compounds 6a-6l showed potent
inhibitory activity against the selected bacterial strains with MIC values in the range of 1.08–23.46
µM, including the multidrug resistant strains. Among of them, compounds 6d was identified as the
most promising one, having superior activity to gatifloxacin, moxiflocaxin, norfloxacin, oxacillin,
and penicillin against the tested multidrug-resistant strains. Furthermore, compound 6d also
exhibited significant anticancer activity against lung (A549) and gastric cancer cells (SGC7901),
with IC50 of 4.44 and 1.51 µM, respectively. To understand the binding pattern, molecular docking
of representative 6d was performed, which demonstrated that compound 6d has a forceful binding
with the E. coli FabH-CoA, and that the aminoguanidine and arylsulfonylindole moieties of
compound 6d play a significant role in binding with the target site. These findings strongly
support the assumption that aminoguanidine and arylsulfonylindole moieties are good options for
the development of new antimicrobial and anticancer agents.
4. Experimental section
4.1. Instruments and reagents
All the reagents and solvents were purchased from Aladdin (Shanghai, China) or Sinopharm
Chemical Reagent Co. Ltd. (Shanghai, China), and were used as received. Melting points were
determined in open capillary tubes and are uncorrected. Reaction courses were monitored by
thin-layer chromatography (TLC) on silica gel-precoated F254 plates (Merck, Darmstadt,
Germany). Developed plates were examined with UV lamps (254 nm). Nuclear magnetic
resonance spectroscopy was performed on an AV-300 spectrometer (Bruker, Zurich, Switzerland)
operating at 300 MHz for 1H and 75 MHz for 13C and using DMSO-d6 as the solvent and
tetramethylsilane as the internal standard. Matrix-assisted laser desorption/ionization
time-of-flight mass spectrometry (MALDI-MS) experiments were performed on a Bruker
ultrafleXtreme MALDI-TOF/TOF mass spectrometer (Bruker Daltonik GmbH, Leipzig, Germany)
equipped with a smartbeam II laser (1000 Hz).
4.2. Synthesis method and spectral data
4.2.1. General procedure for the preparation of compounds 3a–3d
To a 50-mL round-bottom flask, 1H-indole (1a, 1 mmol), benzenesulfonyl chloride (2a, 1.2
mmol), sodium hydroxide (1.75 mmol), and benzyltriethylammonium chloride (TEBA, 0.1 mmol)

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were added along with 30 mL of dry dichloromethane. The resulting solution was stirred at room
temperature. The reaction was monitored with TLC. Upon completion, the reaction was poured
into 15 mL water and the resulting aqueous solution was extracted with dichloromethane (30 mL
× 3). The combined organic layers were dried over anhydrous Na2SO4 and concentrated in vacuo
to obtain a white crude solid of 3a, which was directly used in the next step without purification.
Compounds 3b-3d were obtained using the same method as that for 3a.
4.2.2. General procedure for the preparation of compounds 4a–4b
To a cooled (0-5 °C) solution of dimethyl formamide (DMF, 10 mL), 3 mL POCl3 was added
slowly and stirred for 20 min. To the solution, 1H-indole (1a, 10 mmol) dissolved in 5 mL DMF
was added and stirred at 35 °C for 1 h. The resulting reaction mixture was poured into 6 mL ice
water and then adjusted to PH = 8~9 using 30% aqueous sodium hydroxide, which resulted in a
white precipitate. The precipitate was filtered and dried to yield compound 4a. Compound 4b was
obtained using the same method as that for 4a.
4.2.3. General procedure for the preparation of compounds 5a–5h
To a 100-mL round-bottom flask with AlCl3 (6.0 mmol) and 15 mL dry dichloromethane, 3
mmol of acetyl chloride (for 5a-5d) or propionic anhydride (for 5e-5h) was added drop wise and
the reaction was stirred at room temperature for 20 min; the dichloromethane solution of
compound 3 was added to the reaction and the resulting solution was stirred for 1 h. The reaction
was monitored with TLC. Upon completion, the reaction was poured into 30 mL ice water and the
resulting aqueous solution was extracted with dichloromethane (30 mL × 3). The combined
organic layers were washed with saturated potassium bicarbonate solution and dried with
anhydrous Na2SO4. The organic layer was evaporated to dryness to furnish a white crude solid of
5, which was directly used in the next step without purification.
4.2.4. General procedure for the preparation of compounds 5i–5l
To a 50-mL round-bottom flask, compound 4a (1 mmol), benzenesulfonyl chloride (2a, 1.2
mmol), sodium hydroxide (1.75 mmol), and benzyltriethylammonium chloride (TEBA, 0.1 mmol)
were added along with 30 mL of dry dichloromethane. The resulting solution was stirred at room
temperature. The reaction was monitored with TLC. Upon completion, the reaction was poured
into 15 mL water and the resulting aqueous solution was extracted with dichloromethane (30 mL
× 3). The combined organic layers were dried over anhydrous Na2SO4 and concentrated in vacuo
to obtain a white crude solid of 5i which was directly used in the next step without purification.
The compounds 5j-5l were obtained using the same method as that for 5i.
4.2.5. General procedure for the preparation of compounds 6a-6l
Compound 5 (0.5 mmol) was dissolved in 5 mL methanol and 6 drops of concentrated
hydrochloric acid were added to the solution. The reaction was stirred for 5 min. Then,
aminoguanidine hydrochloride (0.45 mmol) was added to the resulting solution and stirred at
110 °C for 2 h. After cooling, the solvent was evaporated in vacuo, followed by the purification of
the resulting residue by silica gel column chromatography (dichloromethane/methanol = 6/1) and
acidized with concentrated hydrochloric acid to generate a pure solid 6a-6l.
4.2.6. General procedure for the preparation of compounds 7a-7l
To a 50-mL round-bottom flask, compound 5a (1 mmol), semicarbazide hydrochloride (1
mmol), and sodium acetate (1 mmol) were added along with 10 mL of 50% ethanol. The mixture

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was stirred at 110 °C for 9 h. After cooling, the solvent was evaporated in vacuo, followed by
purification of the resulting residue by silica gel column chromatography
(dichloromethane/methanol = 60/1) to generate a white solid 7a. The compounds 7b-7l were
obtained using the same method as that for 7a.
4.2.7. General procedure for the preparation of compounds 8a-8l
Thiosemicarbazide (1 mmol) and potassium hydroxide (1 mmol) were dissolved in 10 mL
ethanol and stirred for 30 min. The resulting solution was added to a solution of compound 5b (1
mmol) in 10 mL ethanol. The mixture was stirred at 110 °C for 3 h. The reaction was cooled,
which resulted in a white precipitate that was then recrystallized in alcohol to obtain compound
8a. The compounds 8b-8l were obtained using the same method as that for 8a.
2-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)ethylidene)hydrazine-1-carboximidamide (6a)
1
White solid, m.p. 256 ºC, yield 30.6%. H-NMR (DMSO-d6, 300MHz): δ 2.47 (s, 3H, CH3),
7.30-7.72 (m, 9H, Ph-H, guanidyl-H), 7.97 (d, 1H, J = 8.2 Hz, Ph-H), 8.08 (d, 2H, J = 7.3 Hz,
Ph-H), 8.28 (d, 1H, J = 7.9 Hz, Ph-H), 8.42 (s, 1H, N-CH), 11.26 (s, 1H, HCl). 13C-NMR
(DMSO-d6, 75MHz): δ 156.42, 149.94, 137.11, 135.39, 135.17, 130.42, 129.40, 127.37, 127.33,
126.05, 124.84, 124.50, 121.03, 113.32, 16.62. ESI-HRMS calcd for C17H18N5O2S+ ([M + H]+):
356.1176; found: 356.1172.
2-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)ethylidene)hydrazine-1-carboximidamide (6b)
1
White solid, m.p. 243 ºC, yield 61.4%. H-NMR (DMSO-d6, 300MHz): δ 2.46 (s, 3H, CH3),
7.55-7.76 (m, 4H, Ph-H), 7.82 (br.s, 4H, guanidyl-H), 7.91-8.09 (m, 3H, Ph-H), 8.34 (d, 1H, J =
1.8 Hz, Ph-H), 8.47 (s, 1H, N-CH), 11.31 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.63,
149.71, 136.85, 135.60, 134.00, 130.51, 130.43, 129.15, 128.80, 127.40, 126.68, 120.48, 117.74,
115.27, 16.72. ESI-HRMS calcd for C17H17BrN5O2S+ ([M + H]+): 434.0281; found: 434.0272.
2-(1-(1-Tosyl-1H-indol-3-yl)ethylidene)hydrazine-1-carboximidamide (6c)
1
light red solid, m.p. 184-185 ºC, yield 86.4%. H-NMR (DMSO-d6, 300MHz): δ 2.32 (s, 3H,
CH3), 2.47 (s, 3H, CH3), 7.32 (t, 1H, J = 7.2 Hz, Ph-H), 7.40 (d, 2H, J = 8.1 Hz, Ph-H), 7.41 (t, 1H,
J = 7.2 Hz, Ph-H), 7.73 (br.s, 4H, guanidyl-H), 7.95 (d, 3H, J = 8.1 Hz, Ph-H), 8.27 (d, 1H, J = 7.7
Hz, Ph-H), 8.39 (s, 1H, N-CH), 11.26 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.40,
150.01, 146.33, 135.16, 134.21, 130.81, 129.44, 127.42, 127.31, 125.97, 124.76, 124.45, 120.85,
113.34, 21.50, 16.62. ESI-HRMS calcd for C18H20N5O2S+ ([M + H]+): 370.1332; found:
370.1326.
2-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)ethylidene)hydrazine-1-carboximidamide (6d)
1
White solid, m.p. 246-248 ºC, yield 75.4%. H-NMR (DMSO-d6, 300MHz): δ 2.33 (s, 3H,
Ph-CH3), 2.44 (s, 3H, N=C-CH3), 7.42 (d, 2H, J = 8.0 Hz, Ph-H), 7.56 (d, 1H, J = 8.9 Hz, Ph-H),
7.79 (br.s, 4H, guanidyl-H), 7.91 (d, 1H, J = 8.9 Hz, Ph-H), 7.95 (d, 2H, J = 8.0 Hz, Ph-H), 8.35 (s,
1H, Ph-H), 8.44 (s, 1H, N-CH), 11.25 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.57,
149.79, 146.61, 133.99, 133.94, 130.91, 130.47, 129.13, 128.73, 127.45, 126.62, 120.31, 117.65,
115.29, 21.53, 16.67. ESI-HRMS calcd for C18H19BrN5O2S+ ([M + H]+): 448.0437; found:
448.0431.
2-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)propylidene)hydrazine-1-carboximidamide (6e)

ACCEPTED MANUSCRIPT
Dark red solid, m.p. 119-120 ºC, yield 72.3%. 1H-NMR (DMSO-d6, 300MHz): δ 1.15 (t, 3H, J
= 7.4 Hz, CH3), 2.97 (q, 2H, J = 7.2 Hz, CH2), 7.31-7.71 (m, 5H, Ph-H), 7.73 (br.s, 4H,
guanidyl-H), 7.98 (d, 1H, J = 8.2 Hz, Ph-H), 8.07 (d, 2H, J = 7.7 Hz, Ph-H), 8.24 (d, 2H, J = 7.8
Hz, Ph-H), 8.42 (s, 1H, N-CH), 11.40 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.61,
154.46, 137.05, 135.39, 135.28, 130.41, 129.05, 127.62, 127.35, 126.06, 124.88, 124.51, 119.81,
113.36, 22.47, 11.89. ESI-HRMS calcd for C18H20N5O2S+ ([M + H]+): 370.1332; found:
370.1330.
2-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)propylidene)hydrazine-1-carboximidamide (6f)
1
White solid, m.p. 260 ºC, yield 96.0%. H-NMR (DMSO-d6, 300MHz): δ 1.13 (t, 3H, J = 7.3
Hz, CH3), 2.94 (q, 2H, J = 7.2 Hz, CH2), 7.56-7.74 (m, 4H, Ph-H), 7.78 (br.s, 4H, guanidyl-H),
7.94 (d, 1H, J = 8.8 Hz, Ph-H), 8.07 (d, 2H, J = 7.3 Hz, Ph-H), 8.32 (d, 1H, J = 1.8 Hz, Ph-H),
8.45 (s, 1H, N-CH), 11.39 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.65, 154.22, 136.82,
135.62, 134.13, 130.50, 130.11, 129.49, 128.82, 127.37, 126.69, 119.26, 117.76, 115.32, 22.49,
11.73. ESI-HRMS calcd for C18H19BrN5O2S+ ([M + H]+): 448.0437; found: 448.0422.
2-(1-(1-Tosyl-1H-indol-3-yl)propylidene)hydrazine-1-carboximidamide (6g)
Dark red solid, m.p. 175-176 ºC, yield 60.0%. 1H-NMR (DMSO-d6, 300MHz): δ 1.15 (t, 3H, J
= 7.3 Hz, CH2CH3), 2.30 (s, 3H, Ph-CH3), 2.97 (q, 2H, J = 7.4 Hz, CH2), 7.30-7.44 (m, 4H, Ph-H),
7.77 (br.s, 4H, guanidyl-H), 7.93-7.97 (m, 3H, Ph-H), 8.24 (d, 1H, J = 7.8 Hz, Ph-H), 8.39 (s, 1H,
N-CH), 11.43 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 156.50, 154.57, 146.33, 135.28,
134.17, 130.79, 129.10, 127.59, 127.39, 125.99, 124.80, 124.44, 119.62, 113.39, 22.42, 21.49,
11.88. ESI-HRMS calcd for C19H22N5O2S+ ([M + H]+): 384.1489; found: 384.1478.
2-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)propylidene)hydrazine-1-carboximidamide (6h)
1
White solid, m.p. 242-244 ºC, yield 73.7%. H-NMR (DMSO-d6, 300MHz): δ 1.17 (t, 3H, J =
7.4 Hz, CH2CH3), 2.33 (s, 3H, Ph-CH3), 2.88 (q, 2H, J = 7.5 Hz, CH2), 7.32 (d, 2H, J = 8.3 Hz,
Ph-H), 7.45 (dd, 1H, J = 8.8 Hz, J = 1.9 Hz, Ph-H), 7.62 (br.s, 4H, guanidyl-H), 7.86 (d, 3H, J =
8.3 Hz, Ph-H), 8.25 (s, 2H, Ph-H, N-CH), 11.18 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ
156.47, 153.93, 146.10, 134.18, 134.12, 130.52, 129.47, 129.42, 128.43, 127.23, 126.40, 119.00,
117.59, 115.03, 22.58, 21.60, 11.59. ESI-HRMS calcd for C19H21BrN5O2S+ ([M + H]+):
462.0594; found: 462.0588.
2-((1-(Phenylsulfonyl)-1H-indol-3-yl)methylene)hydrazine-1-carboximidamide (6i)
1
White solid, m.p. 246-247 ºC, yield 67.1%. H-NMR (DMSO-d6, 300MHz): δ 7.35 (t, 1H, J =
7.5 Hz, Ph-H), 7.45 (t, 1H, J = 7.7 Hz, Ph-H), 7.60-7.75 (m, 7H, Ph-H, guanidyl-H), 7.97 (d, 1H, J
= 8.2 Hz, Ph-H), 8.03 (d, 2H, J = 7.7 Hz, Ph-H), 8.36 (d, 1H, J = 7.9 Hz, Ph-H), 8.39 (s, 1H,
N-CH), 8.48 (s, 1H, CH=N), 12.08 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 155.59, 142.77,
137.03, 135.50, 135.13, 131.59, 130.51, 127.30, 126.87, 126.43, 124.89, 124.02, 117.59, 113.43.
ESI-HRMS calcd for Chemical Formula: C16H16N5O2S+ ([M + H]+): 342.1019; found:
342.1018.
2-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)methylidene)hydrazine-1-carboximidamide (6j)
1
White solid, m.p. 224 ºC, yield 57.9%. H-NMR (DMSO-d6, 300MHz): δ 7.58-7.75 (m, 4H,

ACCEPTED MANUSCRIPT
Ph-H), 7.77 (br.s, 4H, guanidyl-H), 7.93 (d, 1H, J = 8.8 Hz, Ph-H), 8.03 (dd, 2H, J1 = 7.3 Hz, J2 =
1.3 Hz, Ph-H), 8.36 (s, 1H, CH=N), 8.45 (d, 1H, J = 1.7 Hz, Ph-H), 8.54 (s, 1H, N-CH), 12.04 (s,
1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 155.63, 142.38, 136.77, 135.74, 133.99, 132.64,
130.61, 129.27, 128.59, 127.35, 125.80, 117.97, 116.94, 115.39. ESI-HRMS calcd for
C16H15BrN5O2S+ ([M + H]+): 420.0124; found: 420.0120.
2-((1-Tosyl-1H-indol-3-yl)methylene)hydrazine-1-carboximidamide (6k)
1
Light yellow solid, m.p. 160-161 ºC, yield 69.6%. H-NMR (DMSO-d6, 300MHz): δ 2.30 (s,
3H, CH3), 7.32-7.47 (m, 4H, Ph-H), 7.72 (br.s, 4H, guanidyl-H), 7.90 (d, 2H, J = 8.2 Hz, Ph-H),
7.95 (d, 1H, J = 8.3 Hz, Ph-H), 8.37 (d, 1H, J = 7.8 Hz, Ph-H), 8.40 (s, 1H, N-CH), 8.45 (s, 1H,
CH=N), 12.03 (br.s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 155.54, 146.45, 142.83, 135.10,
134.10, 131.60, 130.90, 127.35, 126.85, 126.36, 124.82, 123.97, 117.42, 113.44, 21.52.
ESI-HRMS calcd for C17H18N5O2S+ ([M + H]+): 356.1176; found: 356.1166.
2-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)methylidene)hydrazine-1-carboximidamide (6l)
1
White solid, m.p. 246-247 ºC, yield 66.7%. H-NMR (DMSO-d6, 300MHz): δ 2.33 (s, 3H,
CH3), 7.43 (d, 2H, J = 8.0 Hz, Ph-H), 7.59 (d, 1H, J = 8.7 Hz, Ph-H), 7.76 (br.s, 4H, guanidyl-H),
7.91 (d, 3H, J = 8.4 Hz, Ph-H), 8.35 (s, 1H, Ph-H), 8.45 (s, 1H, N-CH), 8.51 (s, 1H, CH=N), 11.31
(s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 155.61, 146.75, 142.45, 133.98, 133.85, 132.68,
131.00, 129.19, 128.57, 127.39, 125.76, 117.89, 116.79, 115.41, 21.55. ESI-HRMS calcd for
C17H17BrN5O2S+ ([M + H]+): 434.0281; found: 434.0274.
1-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)ethylidene)semicarbazide (7a)
1
White solid, m.p. 211-213 ºC, yield 32.0%. H-NMR (DMSO-d6, 300MHz): δ 2.29 (s, 3H,
CH3), 6.29 (s, 2H, NH2), 7.30-7.72 (m, 5H, Ph-H), 7.95-8.06 (m, 3H, Ph-H), 8.18 (s, 1H, N-CH),
8.28 (d, 1H, J = 7.7 Hz, Ph-H), 9.37 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 157.38, 142.14,
137.24, 135.34, 135.22, 130.34, 127.84, 127.31, 127.27, 125.83, 124.70, 124.11, 122.38, 113.43,
15.07. ESI-HRMS calcd for C17H17N4O3S+ ([M + H]+): 357.1016; found: 357.1014.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)ethylidene)semicarbazide (7b)
1
White solid, m.p. 235 ºC, yield 58.0%. H-NMR (DMSO-d6, 300MHz): δ 2.27 (s, 3H, CH3),
6.29 (br.s, 2H, NH2), 7.53-7.72 (m, 4H, Ph-H), 7.90-8.06 (m, 3H, Ph-H), 8.24 (d, 1H, J = 1.8 Hz,
Ph-H), 8.44 (s, 1H, N-CH), 9.43 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.26, 141.75,
137.00, 135.44, 134.18, 130.43, 129.69, 128.50, 128.36, 127.30, 126.47, 121.74, 117.44, 115.40,
15.00. ESI-HRMS calcd for C17H16BrN4O3S+ ([M + H]+): 435.0121; found: 435.0117.
1-(1-(1-Tosyl-1H-indol-3-yl)ethylidene)semicarbazide (7c)
1
White solid, m.p. 229 ºC, yield 67.0%. H-NMR (CDCl3, 300MHz): δ 2.31 (s, 3H, CH3), 2.37
(s, 3H, CH3), 5.78 (br.s, 2H, NH2), 7.27 (d, 2H, J = 8.8 Hz, Ph-H), 7.32-7.41 (m, 2H, Ph-H), 7.81
(d, 2H, J = 8.8 Hz, Ph-H), 7.82 (s, 1H, N-CH), 8.01 (d, 1H, J = 8.1 Hz, Ph-H), 8.14 (d, 1H, J = 7.5
Hz, Ph-H), 8.56 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.64, 145.47, 135.60, 134.84,
130.08, 127.48, 126.94, 126.70, 126.64, 125.52, 124.10, 122.75, 121.15, 113.58, 21.59, 14.47.
ESI-HRMS calcd for C18H19N4O3S+ ([M + H]+): 371.1172; found: 371.1162.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)ethylidene)semicarbazide (7d)

ACCEPTED MANUSCRIPT
White solid, m.p. 234-235 ºC, yield 84.0%. 1H-NMR (DMSO-d6 + CDCl3, 300MHz): δ 2.24 (s,
3H, Ph-CH3), 2.31 (s, 3H, N=C-CH3), 6.11 (br.s, 2H, NH2), 7.30 (d, 2H, J = 8.3 Hz, Ph-H), 7.43
(dd, 1H, J1 = 8.8, J2 = 1.8 Hz, Ph-H), 7.82-7.86 (m, 3H, Ph-H), 8.02 (s, 1H, N-CH), 8.36 (d, 1H, J
= 1.8 Hz, Ph-H), 9.40 (s, 1H, CONH). 13C-NMR (DMSO-d6 + CDCl3, 75MHz): δ 157.38, 145.91,
141.58, 134.30, 134.18, 130.48, 129.63, 128.11, 127.78, 127.14, 126.20, 121.52, 117.28, 115.10,
21.59, 14.95. ESI-HRMS calcd for C18H18BrN4O3S+ ([M + H]+): 449.0278; found: 449.0274.
1-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)propylidene)semicarbazide (7e)
1
White solid, m.p. 206 ºC, yield 23.0%. H-NMR (DMSO-d6, 300MHz): δ 1.11 (t, 3H, J = 6.6
Hz, CH3), 2.76 (q, 2H, J = 6.7 Hz, CH2), 6.21 (s, 2H, NH2), 7.28-7.61 (m, 5H, Ph-H), 7.96-8.03
(m, 4H, Ph-H), 8.22 (s, 1H, N-CH), 9.51 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 157.43,
146.40, 137.40, 135.50, 134.78, 129.97, 128.20, 127.06, 126.40, 125.56, 124.42, 123.89, 121.22,
113.38, 21.09, 11.21. ESI-HRMS calcd for C18H19N4O3S+ ([M + H]+): 371.1172; found:
371.1170.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl) propylidene)semicarbazide (7f)
1
White solid, m.p. 241 ºC, yield 65.0%. H-NMR (DMSO-d6, 300MHz): δ 1.05 (t, 3H, J = 7.3
Hz, CH3), 2.76 (q, 2H, J = 7.5 Hz, CH2), 6.26 (br.s, 2H, NH2), 7.53-7.73 (m, 4H, Ph-H), 7.93 (d,
1H, J = 8.8 Hz, Ph-H), 8.05 (d, 2H, J = 7.4 Hz, Ph-H), 8.24 (s, 1H, N-CH), 8.44 (s, 1H, Ph-H),
9.58 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.09, 145.99, 136.93, 135.47, 134.28,
130.44, 130.04, 128.52, 127.93, 127.29, 126.53, 120.60, 117.46, 115.43, 20.87, 11.22. ESI-HRMS
calcd for C18H18BrN4O3S+ ([M + H]+): 449.0278; found: 449.0275.
1-(1-(1-Tosyl-1H-indol-3-yl)propylidene)semicarbazide (7g)
1
White solid, m.p. 214-216 ºC, yield 66.0%. H-NMR (DMSO-d6, 300MHz): δ 1.07 (t, 3H, J =
7.4 Hz, CH2CH3), 2.31 (s, 3H, Ph-CH3), 2.79 (q, 2H, J = 7.4 Hz, CH2), 6.27 (br.s, 2H, NH2),
7.31-7.40 (m, 4H, Ph-H), 7.90-7.96 (m, 3H, Ph-H), 8.14 (s, 1H, N-CH), 8.25 (d, 1H, J = 7.8 Hz,
Ph-H), 9.52 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.27, 146.51, 146.15, 135.44,
134.26, 130.74, 128.15, 127.30, 126.92, 125.78, 124.63, 124.06, 121.06, 113.50, 21.49, 20.90,
11.35. ESI-HRMS calcd for C19H21N4O3S+ ([M + H]+): 385.1329; found: 385.1321.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)propylidene)semicarbazide (7h)
1
White solid, m.p. 237-238 ºC, yield 68.0%. H-NMR (DMSO-d6, 300MHz): δ 1.10 (t, 3H, J =
7.5 Hz, CH2CH3), 2.30 (s, 3H, Ph-CH3), 2.69 (q, 2H, J = 7.5 Hz, CH2), 6.04 (s, 2H, NH2), 7.26 (d,
2H, J = 8.2 Hz, Ph-H), 7.39 (dd, 1H, J1 = 8.8, J2 = 2.0 Hz, Ph-H), 7.78 (d, 2H, J = 8.2 Hz, Ph-H),
7.81 (d, 1H, J = 8.8 Hz, Ph-H), 7.86 (d, 1H, J = 2.0 Hz, Ph-H), 8.31 (s, 1H, N-CH), 9.36 (s, 1H,
CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.40, 150.45, 146.07, 145.83, 134.29, 134.26, 130.34,
129.90, 128.07, 126.96, 126.13, 120.30, 117.34, 114.98, 21.60, 21.21, 10.97. ESI-HRMS calcd for
C19H20BrN4O3S+ ([M + H]+): 463.0434; found: 463.0429.
1-((1-(Phenylsulfonyl)-1H-indol-3-yl)methylene)semicarbazide (7i)
1
White solid, m.p. 197-199 ºC, yield 63.0%. H-NMR (DMSO-d6, 300MHz): δ 5.86 (s, 2H,
NH2), 7.29-7.62 (m, 5H, Ph-H), 7.83 (s, 1H, CH=N), 7.90-7.99 (m, 3H, Ph-H), 8.09 (s, 1H, N-CH),
8.13 (d, 1H, J = 8.04 Hz, Ph-H), 10.23 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 162.18,

ACCEPTED MANUSCRIPT
142.25, 140.43, 140.14, 139.12, 134.31, 132.48, 132.06, 131.53, 130.47, 128.95, 127.42, 123.34,
118.11. ESI-HRMS calcd for C16H15N4O3S+ ([M + H]+): 343.0859; found: 343.0855.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl) methylidene)semicarbazide (7j)
1
White solid, m.p. 208-210 ºC, yield 48.0%. H-NMR (DMSO-d6+ CDCl3, 300MHz): δ 6.02
(br.s, 2H, NH2), 7.42-7.62 (m, 4H, Ph-H), 7.82-7.92 (m, 3H, Ph-H), 7.96 (s, 1H, CH=N), 8.00 (s,
1H, N-CH), 8.18 (d, 1H, J = 1.4 Hz, Ph-H), 10.29 (s, 1H, CONH). 13C-NMR (DMSO-d6 + CDCl3,
75MHz): δ 157.15, 137.19, 134.83, 134.76, 134.10, 129.89, 129.13, 129.03, 128.52, 126.97,
125.23, 118.05, 117.47, 115.09. ESI-HRMS calcd for C16H14BrN4O3S+ ([M + H]+): 420.9965;
found: 420.9960.
1-(1-(1-Tosyl-1H-indol-3-yl)methylidene)semicarbazide (7k)
White solid, m.p. 217-218 ºC, yield 46.0%. 1H-NMR (DMSO-d6 + CDCl3, 300MHz): δ 2.30 (s,
3H, CH3), 6.21 (br.s, 2H, NH2), 7.25 (d, 2H, J = 8.0 Hz, Ph-H), 7.30 (d, 1H, J = 7.3 Hz, Ph-H),
7.74 (d, 2H, J = 8.0 Hz, Ph-H), 7.82 (s, 1H, CH=N), 7.83-7.89 (m, 2H, Ph-H), 8.01 (s, 1H, N-CH),
8.07 (d, 1H, J = 7.8 Hz, Ph-H), 10.19 (s, 1H, CONH). 13C-NMR (DMSO-d6, 75MHz): δ 157.21,
145.64, 135.28, 134.53, 130.54, 130.25, 127.86, 127.35, 126.93, 125.65, 124.18, 122.84, 118.57,
113.36, 21.58. ESI-HRMS calcd for C17H17N4O3S+ ([M + H]+): 357.1016; found: 357.1012.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)methylidene)semicarbazide (7l)
1
White solid, m.p. 225 ºC, yield 52.0%. H-NMR (DMSO-d6, 300MHz): δ 2.31 (s, 3H, CH3),
6.42 (br.s, 2H, NH2), 7.39 (d, 2H, J = 7.8 Hz, Ph-H), 7.56 (dd, 1H, J1 = 8.4 Hz, J2 = 1.8 Hz, Ph-H),
7.87-7.92 (m, 3H, Ph-H), 8.03 (s, 1H, CH=N), 8.28(s, 1H, N-CH), 8.31 (d, 1H, J = 1.8 Hz, Ph-H),
10.31 (s, 1H, HCl). 13C-NMR (DMSO-d6, 75MHz): δ 157.00, 146.50, 134.55, 134.08, 133.98,
130.88, 130.03, 129.16, 128.81, 127.30, 125.46, 118.12, 117.51, 115.49, 21.52. ESI-HRMS calcd
for C17H16BrN4O3S+ ([M + H]+): 435.0121; found: 435.0113.
1-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)ethylidene) thiosemicarbazide (8a)
1
White solid, m.p. 218-219 ºC, yield 56.0%. H-NMR (DMSO-d6, 300MHz): δ 2.41 (s, 3H,
CH3), 7.30-7.73 (m, 6H, Ph-H), 7.97 (d, 1H, J = 7.9 Hz, Ph-H), 8.07 (d, 2H, J = 7.7 Hz, Ph-H),
8.25 (s, 1H, NH2), 8.35 (s, 1H, N-CH, NH2), 10.31 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ
180.12, 147.54, 137.96, 136.15, 136.05, 131.21, 129.82, 128.35, 128.17, 126.77, 125.65, 125.05,
122.52, 114.21, 16.69. ESI-HRMS calcd for C17H17N4O2S2+ ([M + H]+): 373.0787; found:
373.0785.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)ethylidene)thiosemicarbazide (8b)
1
White solid, m.p. 234 ºC, yield 80.0%. H-NMR (DMSO-d6, 300MHz): δ 2.38 (s, 3H, CH3),
7.54-7.76 (m, 5H, Ph-H), 7.91-8.09 (m, 3H, Ph-H), 8.32 (br.s, 1H, NH2), 8.39 (s, 1H, N-CH), 8.40
(br.s, 1H, NH2), 10.36 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.42, 146.67, 136.91,
135.57, 134.08, 130.50, 129.97, 129.39, 128.64, 127.38, 121.11, 117.61, 115.31, 99.99, 15.84.
ESI-HRMS calcd for C17H16BrN4O2S2+ ([M + H]+): 450.9893; found: 450.9892.
1-(1-(1-Tosyl-1H-indol-3-yl)ethylidene)thiosemicarbazide (8c)
White solid, m.p. 233 ºC, yield 70.3%. 1H-NMR (DMSO-d6 + CDCl3, 300MHz): δ 2.34 (s, 3H,

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CH3), 2.39 (s, 3H, CH3), 7.29-7.34 (m, 5H, Ph-H), 7.82-7.93 (m, 3H, Ph-H), 8.05 (s, 1H, NH2),
8.16 (s, 1H, NH2), 8.21 (s, 1H, N-CH), 10.13 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ
179.27, 145.71, 135.34, 134.52, 130.38, 130.32, 128.03, 127.54, 127.15, 127.07, 125.50, 124.33,
121.50, 113.33, 21.58, 15.56. ESI-HRMS calcd for C18H19N4O2S2+ ([M + H]+): 387.0944;
found: 387.0936.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)ethylidene)thiosemicarbazide (8d)
1
White solid, m.p. 203-205 ºC, yield 82.6%. H-NMR (DMSO-d6, 300MHz): δ 2.33 (s, 3H,
Ph-CH3), 2.38 (s, 3H, N=C-CH3), 7.40-7.55 (m, 4H, Ph-H), 7.89-7.96 (m, 3H, Ph-H), 8.35 (br.s,
3H, NH2, N-CH), 10.34 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.45, 159.64, 146.53,
134.10, 134.02, 130.89, 129.38, 128.63, 128.56, 127.52, 127.42, 121.02, 117.53, 115.34, 21.52,
15.96. ESI-HRMS calcd for C18H18BrN4O2S 2+ ([M + H]+): 465.0049; found: 465.0043.
1-(1-(1-(Phenylsulfonyl)-1H-indol-3-yl)propylidene)thiosemicarbazide (8e)
1
White solid, m.p. 201 ºC, yield 58.6%. H-NMR (DMSO-d6, 300MHz): δ 1.10 (t, 3H, J = 6.9
Hz, CH3), 2.95 (q, 2H, J = 6.8 Hz, CH2), 7.30-7.41 (m, 3H, Ph-H), 7.58-7.70 (m, 3H, Ph-H), 7.97
(d, 1H, J = 8.0 Hz, Ph-H), 8.06 (d, 2H, J = 7.3 Hz, Ph-H), 8.21 (s, 1H, NH2), 8.31 (s, 2H, N-CH,
NH2), 10.42 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.44, 150.79, 137.12, 135.35,
135.23, 130.38, 128.58, 127.84, 127.33, 125.98, 124.86, 124.11, 120.56, 113.47, 21.51, 11.86.
ESI-HRMS calcd for C18H19N4O2S2+ ([M + H]+): 387.0944; found: 387.0940.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)propylidene)thiosemicarbazide (8f)
1
White solid, m.p. 221 ºC, yield 83.0%. H-NMR (DMSO-d6, 300MHz): δ 1.09 (t, 3H, J = 7.2
Hz, CH3), 2.91 (q, 2H, J = 7.2 Hz, CH2), 7.48 (br.s, 1H, NH2), 7.54-7.75 (m, 4H, Ph-H), 7.93 (d,
1H, J = 8.8 Hz, Ph-H), 8.07 (d, 2H, J = 7.7 Hz, Ph-H), 8.34 (br.s, 1H, NH2), 8.37 (s, 2H, Ph-H,
N-CH), 10.34 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.84, 150.44, 136.92, 135.54,
134.20, 130.64, 130.47, 129.76, 128.64, 127.69, 127.35, 120.10, 117.66, 115.35, 21.53, 11.75.
ESI-HRMS calcd for C18H18BrN4O2S2+ ([M + H]+): 465.0049; found: 465.0046.
1-(1-(1-Tosyl-1H-indol-3-yl)propylidene)thiosemicarbazide (8g)
1
White solid, m.p. 208 ºC, yield 78.9%. H-NMR (DMSO-d6, 300MHz): δ 1.10 (t, 3H, J = 7.1
Hz, CH2CH3), 2.30 (s, 3H, Ph-CH3), 2.94 (q, 2H, J = 7.1 Hz, CH2), 7.30-7.40 (m, 5H, Ph-H),
7.92-7.97 (m, 3H, Ph-H), 8.21 (br.s, 1H, NH2), 8.30 (s, 1H, N-CH), 8.34 (br.s, 1H, NH2), 10.42 (s,
1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.41, 150.84, 146.26, 135.35, 134.22, 130.77,
128.60, 127.84, 127.36, 125.90, 124.77, 124.07, 120.42, 113.49, 21.59, 21.48, 11.88. ESI-HRMS
calcd for C19H21N4O2S2+ ([M + H]+): 401.1100; found: 401.1096.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)propylidene)thiosemicarbazide (8h)
1
White solid, m.p. 205 ºC, yield 79.7%. H-NMR (DMSO-d6, 300MHz): δ 1.09 (t, 3H, J = 6.6
Hz, CH2CH3), 2.30 (s, 3H, Ph-CH3), 2.91 (q, 2H, J = 6.7 Hz, CH2), 7.39 (d, 2H, J = 7.7 Hz, Ph-H),
7.52-7.89 (m, 3H, Ph-H), 7.93 (d, 2H, J = 7.7 Hz, Ph-H), 8.34 (br.s, 3H, NH2, N-CH), 10.50 (s, 1H,
NH). 13C-NMR (DMSO-d6, 75MHz): δ 179.75, 150.57, 146.50, 134.19, 134.00, 130.85, 129.74,
129.51, 128.55, 127.38, 126.55, 119.96, 117.58, 115.36, 21.81, 21.50, 11.77. ESI-HRMS calcd for
C19H20BrN4O2S2+ ([M + H]+): 479.0206; found: 479.0201.

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1-((1-(Phenylsulfonyl)-1H-indol-3-yl)methylene)thiosemicarbazide (8i)
1
White solid, m.p. 201-202 ºC, yield 26.0%. H-NMR (DMSO-d6, 300MHz): δ 6.89 (s, 1H,
NH2), 7.19 (s, 1H, NH2), 7.28-7.55 (m, 5H, Ph-H), 7.92-8.03 (m, 5H, Ph-H, CH=N), 8.25 (s, 1H,
N-CH), 10.63 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 177.50, 139.15, 137.58, 135.46,
134.36, 130.01, 129.54, 126.97, 126.81, 126.01, 124.42, 122.37, 117.11, 113.57, 77.47, 77.04,
76.62. ESI-HRMS calcd for C16H15N4O2S2+ ([M + H]+): 359.0631; found: 359.0629.
1-(1-(5-Bromo-1-(phenylsulfonyl)-1H-indol-3-yl)methylidene)thiosemicarbazide (8j)
1
White solid, m.p. 207-210 ºC, yield 51.5%. H-NMR (DMSO-d6+ CDCl3, 300MHz): δ7.27
(br.s, 1H, NH2), 7.41 (br.s, 1H, NH2), 7.45-7.60 (m, 3H, Ph-H), 7.81-7.96 (m, 4H, Ph-H), 8.01 (s,
1H, Ph-H), 8.16 (s, 1H, CH=N), 8.19 (s, 1H, N-CH), 11.43 (s, 1H, NH). 13C-NMR (DMSO-d6 +
CDCl3, 75MHz): δ 178.23, 137.64, 137.15, 134.85, 134.07, 130.35, 129.87, 128.83, 128.67,
126.97, 125.22, 117.66, 117.45, 114.99. ESI-HRMS calcd for C16H14BrN4O2S2+ ([M + H]+):
436.9736; found: 436.9733.
1-(1-(1-Tosyl-1H-indol-3-yl)methylidene)thiosemicarbazide (8k)
1
White solid, m.p. 206 ºC, yield 50.0%. H-NMR (CDCl3, 300MHz): δ 2.33 (s, 3H, CH3), 6.94
(s, 1H, NH2), 7.16 (s, 1H, NH2), 7.23 (d, 2H, J = 8.2 Hz, Ph-H), 7.32-7.41 (m, 2H, Ph-H), 7.80 (d,
2H, J = 8.2 Hz, Ph-H), 7.92 (s, 1H, CH=N), 7.98 (d, 1H, J = 8.4 Hz, Ph-H), 8.02 (d, 1H, J = 8.2
Hz, Ph-H), 8.24 (s, 1H, N-CH), 10.61 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 176.99,
145.67, 139.46, 135.45, 134.59, 130.14, 127.24, 127.03, 126.77, 125.91, 124.32, 122.33, 116.85,
113.59, 21.59. ESI-HRMS calcd for C17H17N4O2S2+ ([M + H]+): 373.0787; found: 373.0782.
1-(1-(5-Bromo-1-tosyl-1H-indol-3-yl)methylidene)thiosemicarbazide (8l)
1
White solid, m.p. 225 ºC, yield 68.6%. H-NMR (DMSO-d6, 300MHz): δ 2.33 (s, 3H, CH3),
7.42 (d, 2H, J = 7.5 Hz, Ph-H), 7.56 (d, 1H, J = 7.4 Hz Ph-H), 7.78 (br.s, 1H, NH2), 7.91 (d, 3H, J
= 7.5 Hz, Ph-H), 8.19 (br.s, 1H, NH2), 8.24 (s, 1H, CH=N), 8.35 (s, 1H, Ph-H), 8.39 (s, 1H,
N-CH), 11.44 (s, 1H, NH). 13C-NMR (DMSO-d6, 75MHz): δ 178.20, 146.63, 137.83, 134.02,
133.96, 131.58, 130.93, 128.99, 128.85, 127.39, 125.58, 117.69, 117.48, 115.41, 21.54.
ESI-HRMS calcd for C17H16BrN4O2S2+ ([M + H]+): 450.9893; found: 450.9889.
4.3. Evaluation of anti-bacterial activity in vitro
Test bacteria were grown to mid-log phase in Mueller-Hinton broth (MHB) or Tryptone Soya
Broth (TSB) and diluted 1000-fold in the same medium. Bacteria (105 CFU/mL) were inoculated
into MHB or TSB and dispensed at 0.2 mL/well in a 96-well microtiter plate. As positive controls,
gatifloxacin, moxifloxacin, norfloxacin, oxacillin, and penicillin were used. Test compounds were
prepared in DMSO, the final concentration of which did not exceed 0.05%. The MIC was defined
as the concentration of a test compound that completely inhibited bacteria growth during 24-h
incubation at 37 °C. Bacteria growth was determined by measuring the absorption at 630 nm using
a microtiter enzyme-linked immunosorbent assay (ELISA) reader. All experiments were carried
out three times.
4.4. Evaluation of cytotoxicity activity in vitro

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Lung cancer cell line (A590), gastric cancer cell line (SGC7901) and human embryonic kidney
293T cells (HEK 293T cells) were used to test the cytotoxic activity of the new compounds. A590,
SGC7901and HEK 293T cells were grown in Dulbecco modified Eagle medium supplemented
with fetal bovine serum (10%), and antibiotics (penicillin-streptomycin mixture (100 U/ml)). Cells
at 80 to 90% confluence were split by trypsin (0.25% in PBS; pH 7.4), and the medium was
changed at 24-h intervals. The cells were cultured at 37 °C in a 5% CO2 incubator. The cells were
grown to three passages, and approximately 1 × 104 cells were seeded into each well of a 96-well
plate and allowed to incubate to allow attachment of the cells to the substrate. After 24 h, the
medium was replaced with DMEM supplemented with 10% FBS containing various
concentrations (0.3, 1, 3, 10, 30, and 100 µmol/L) of test compounds and incubated for 48 h. For
each concentration, three wells were set in parallel. Then, 20 µL of CCK-8 solution was added to
each well. After incubation for 3 h, the optical density was measured at 450 nm using a microtiter
ELISA reader. The IC50 values were defined as the concentrations inhibiting 50% of cell growth.
For the purpose of comparing the safety of these compounds, the selectivity index (SI) was
calculated as ratio between cytotoxicity (IC50) in HEK 293T cells and antibacterial activity (MIC)
(Selectivity index (SI) = IC50 / MIC).
4.5. Propensity of bacterial resistance development
In order to evaluate the propensity of developing bacterial resistance towards the compounds,
one of the potent compound (6d) was used in the study. First, MIC of compound 6d was
determined against S. aureus (Staphylococcus aureus CMCC 25923) and E. coli (Escherichia coli
CMCC 44568), and subsequently the compounds was challenged repeatedly at the 1/2 MIC level.
Norfloxacin was chosen to be the control antibiotic. The initial MIC values of 6d and norfloxacin
were determined against respective bacteria. After the initial MIC experiment, serial passaging
was initiated by transferring bacterial suspension grown at the sub-MIC of the
compound/antibiotic (at MIC/2) and was subjected to another MIC assay. After 22 h incubation
period, cells grown at the sub-MIC of the test compound/antibiotic were once again transferred
and assayed for MIC experiment. The process was repeated for 18 passages for both S. aureus and
E. coli, respectively. The MIC for 6d and norfloxacin was plotted against days to determine the
propensity of bacterial resistance development [41].
4.6. Docking studies
Molecular docking of compound 6d into the E. coli FabH-CoA complex structure (PDB code:
1HNJ) [36] was carried out using the Discovery Studio (version 4.5) as implemented through the
graphical user interface DS–CDOCKER protocol. The 3D structure of 1HNJ in docking study was
downloaded from Protein Data Bank. The three–dimensional structures of 6d was constructed
using Chem. 3D ultra 12.0 software [Chemical Structure Drawing Standard; Cambridge Soft
corporation, USA (2010)], and was energetically minimized by using MMFF94 with 5000
iterations and a minimum RMS gradient of 0.10. For protein preparation, the hydrogen atoms
were added, and water and impurities were removed. The 3D structure of 6d was placed during
the molecular docking procedure. Types of interactions of the docked protein with 6d were
analyzed after molecular docking. Compound would retain 10 poses, and were ranked and
selected by CDOCKER_INTERACTION_ ENERGY.
Acknowledgments: This work was supported by the National Science Foundation of China (No.
81560561) and Natural Science Foundation of Jiangxi Province, China (No. 20161BAB215207).

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341-356.

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Table 1. Inhibitory activity (MIC, µmol/L) of compounds 6a-6l, 7a-7l, and 8a-8l against gram-positive and gram-negative bacteria.
Gram-positive strains
Gram-negative strains
Compound
R1-
R2-
R3-
26003a
22.54
4.62
25923b
22.54
4.62
32067c
31968d
29212e
45.07
9.24
63501f
22.54
25922g
45.07
44568h
27853i
10104j
45.07
6a
6b
6c
6d
6e
6f
H
H
H
CH3
CH3
CH3
CH3
C2H5
C2H5
C2H5
C2H5
H
22.54
1.40
11.27
90.14
5-Br
H
295.61
21.68
4.62
9.24
10.84
4.47
18.48
9.24
>295.61
346.88
>295.61
10.84
4- CH3
4- CH3
H
10.84
4.47
5.42
2.71
43.36
8.94
21.68
10.84
5-Br
H
2.24
286.35
10.84
2.24
286.35
43.36
1.12
>286.35
173.44
>286.35
43.36
21.68
4.47
21.68
10.84
1.12
43.36
8.95
>346.88
4.47
43.36
5-Br
H
H
4.47 >286.35
17.90
4.47
>286.35
334.20
>286.35
>334.20
>277.66
23.46
6g
6h
6i
4- CH3
4- CH3
H
5.22
10.44
2.17
5.22
83.55
1.08
20.89
4.34
10.44
2.17
20.89
20.89
5-Br
H
4.34
138.83
34.71
4.34
>277.66
46.92
5.87
11.73 >375.37
2.37
11.28 >360.56
2.31 >295.61 >295.61
46.92
46.92
19.09
45.12
9.24
11.73
4.77
>375.37
9.55
23.46
6j
5-Br
H
H
H
152.74
11.28
2.31
305.49 >305.49
2.82
1.19
>305.49
45.12
9.55
6k
6l
4- CH3
4- CH3
H
H
5.64
11.28
11.28
11.28
5-Br
H
H
2.31
9.24
2.31
>295.61
>359.55
>294.93
>345.95
>285.71
>345.95
>285.71
>333.33
>277.06
>295.61
>359.55
>294.93
>345.95
>285.71
>345.95
>285.71
>333.33
>277.06
7a
7b
7c
7d
7e
7f
CH3
CH3
CH3
CH3
359.55 >359.55 >359.55 >359.55 >359.55
294.93 294.93 >294.93 >294.93 36.87
89.89
294.93
345.95
8.93
>359.55
>294.93
>345.95
>285.71
>345.95
>285.71
>333.33
>277.06
>359.55
>294.93
>345.95
>285.71
>345.95
>285.71
>333.33
>277.06
5-Br
H
H
4- CH3
4- CH3
H
345.95 >345.95 >345.95 >345.95 >345.95
285.71 >285.71 >285.71 >285.71 >285.71
5-Br
H
C2H5 >345.95
C2H5 >285.71 >285.71 >285.71 >285.71 >285.71
C2H5 333.33 83.33 >333.33 >333.33 >333.33
C2H5 >277.06 >277.06 >277.06 >277.06 >277.06
345.95 >345.95 >345.95 >345.95
>345.95
>285.71
333.33
>277.06
5-Br
H
H
7g
7h
4- CH3
4- CH3
5-Br

ACCEPTED MANUSCRIPT
7i
H
5-Br
H
H
H
H
H
93.57
38.10
44.94
93.57 >374.27 >374.27 >374.27
304.76 >304.76 >304.76 >304.76
179.78 >359.55 >359.55 >359.55
93.57
19.05
>374.27
>304.76
359.55
>294.93
344.09
>284.44
331.61
>275.86
331.61
>275.86
>320.00
267.78
>357.54
>293.58
>343.16
>284.44
0.33
>374.27
>304.76
359.55
>294.93
344.09
>284.44
331.61
>275.86
331.61
>275.86
>320.00
267.78
>357.54
>293.58
>343.16
>284.44
0.33
>374.27
>304.76
359.55
>294.93
344.09
>284.44
331.61
>275.86
331.61
275.86
>320.00
>267.78
357.54
>293.58
343.16
>284.44
5.33
>374.27
>304.76
>359.55
>294.93
>344.09
>284.44
>331.61
>275.86
>331.61
>275.86
>320.00
>267.78
>357.54
>293.58
>343.16
>284.44
5.33
7j
7k
4- CH3
4- CH3
H
H
44.94
7l
5-Br
H
H
294.93 >294.93 >294.93 >294.93 >294.93
344.09 344.09 >344.09 >344.09 >344.09
284.44 >284.44 >284.44 >284.44 >284.44
9.22
8a
CH3
CH3
CH3
CH3
C2H5
C2H5
C2H5
C2H5
H
172.04
284.44
165.80
>275.86
82.90
8b
5-Br
H
H
8c
4- CH3
4- CH3
H
331.61
275.86
64
331.61 >331.61 >331.61
275.86 >275.86 >275.86 >275.86
331.61 >331.61 >331.61 165.80
331.61
8d
5-Br
H
8e
8f
5-Br
H
H
275.86 >275.86 >275.86 >275.86 >275.86
68.97
8g
4- CH3
4- CH3
H
320.00
133.89
320.00 >320.00 >320.00 >320.00
267.78 >267.78 >267.78 >267.78
>320.00
>267.78
>357.54
>293.58
>343.16
>284.44
5.33
8h
5-Br
H
8i
178.77 >357.54 >357.54 >357.54 >357.54
293.58 >293.58 >293.58 >293.58 >293.58
343.16 >343.16 >343.16 >343.16 >343.16
284.44 >284.44 >284.44 >284.44 >284.44
8j
5-Br
H
H
H
8k
4- CH3
4- CH3
—
H
8l
5-Br
—
H
0.33
0.31
0.39
0.31
0.37
0.33 >341.33 >341.33
0.31 >319.20 >319.20
0.39 >401.25 >401.25
0.31 >319.20 >319.20
0.37 >383.23 >383.23
Gatifloxacin
Moxifloxacin
Norfloxacin
Oxacillin
penicillin
—
2.67
2.49
0.31
0.31
—
—
—
4.99
4.99
9.98
0.39
0.39
—
—
—
3.13
6.27
6.27
12.54
319.20
383.23
>319.20
>383.23
>319.20
—
—
—
319.20
383.23
>319.20
383.23
>319.20
95.81
>383.23
—
—
—
a Staphylococcus aureus CMCC(B)26003; b Staphylococcus aureus CMCC 25923; c Streptococcus pyogenes CMCC 32067; d Streptococcus pneumonia CMCC 31968
e Enterococcus faecalis CMCC 29212; f Bacillus subtilis CMCC 63501; g Escherichia coli CMCC 25922; h Escherichia coli CMCC 44568; i Pseudomonas aeruginosa CMCC
27853; j Pseudomonas aeruginosa CMCC 10104.

ACCEPTED MANUSCRIPT
Table 2. Inhibitory activity (MIC, µmol/L) of compounds 6c, 6d, 6h, 6j, 6k, and 6l against clinical isolates of multidrug-resistant strains.
multidrug-resistant Gram-positive strains
multidrug-resistant Gram-negative strains
Compound
R1-
R2-
4- CH3
R3-
CH3
43300a
33591b
BAA-196c
BAA-2111d
>86.72
>71.59
>69.41
>76.37
11.27
>73.90
2.66
5.42
5.42
10.84
6c
H
6d
5-Br
5-Br
5-Br
H
4- CH3
4- CH3
H
CH3
C2H5
H
1.12
2.24
0.56
2.17
2.17
2.39
8.68
2.39
6h
2.39
6j
2.82
5.63
1.15
11.27
1.15
6k
4- CH3
4- CH3
—
H
1.15
6l
5-Br
—
H
Gatifloxacin
Moxifloxacin
Norfloxacin
Oxacillin
penicillin
1.33
0.67
0.62
1.33
1.25
1.57
ND
—
1.25
2.49
—
—
—
1.57
0.78
3.13
—
—
—
159.60
19.95
ND
—
—
—
95.81
>95.81
ND
ND
—
—
—
a Staphylococcus aureus ATCC 43300; b Staphylococcus aureus ATCC 33591; c multi-drug resistant Escherichia coli ATCC BAA-196;
d multi-drug resistant Pseudomonas aeruginosa ATCC BAA-2111; ND: not detected

ACCEPTED MANUSCRIPT
Table 3. The Inhibitory activity (IC50, µmol/L) of compounds 6c, 6d, 6h, 6j, 6k, and 6l against cancer
cell lines A590 and SGC7901 and normal cell lines HEK 293T.
Compound
R1-
R2-
R3-
CH3
CH3
C2H5
H
A590
2.68
SGC7901 HEK 293T
52.99
56.39
57.64
71.61
86.66
73.46
2.38
1.51
3.92
3.06
2.12
4.00
6c
6d
6h
6j
H
4- CH3
4- CH3
4- CH3
H
4.44
5-Br
5-Br
5-Br
H
2.33
14.67
12.22
15.12
6k
6l
4- CH3
4- CH3
H
5-Br
H
Table 4. Selectivity index values of compounds 6c, 6d, 6h, 6j, 6k, and 6l against bacterial strains
(mammal cell was HEK 293T).
6c
4.89
9.78
2.44
19.55
1.22
4.89
2.44
4.89
0.15
4.89
9.78
9.78
6d
6h
6j
6k
6l
Staphylococcus aureus CMCC(B)26003
Staphylococcus aureus CMCC 25923
12.62 13.28
0.47
7.68 31.80
7.68 31.80
25.17 13.28 30.22
0.20 0.42
25.17 53.37 <0.23 30.73 <0.25
6.31 13.28 3.75 1.92 7.95
12.62 26.56 15.01 15.37 31.80
0.20 1.66 7.50 7.68 7.95
Streptococcus pyogenes CMCC 32067
Streptococcus pneumonia CMCC 31968
Enterococcus faecalis CMCC 29212
0.23 <0.24 <0.24
Bacillus subtilis CMCC 63501
Escherichia coli CMCC 25922
Escherichia coli CMCC 44568
50.35 13.28 60.18
<0.20 <0.21 <0.23
7.68 31.80
1.92 <0.25
7.68 <0.25
Pseudomonas aeruginosa CMCC 27853
Pseudomonas aeruginosa CMCC 10104
Methicillin-resistant Staphylococcus aureus ATCC 43300
Methicillin-resistant Staphylococcus aureus ATCC 33591
Multi-drug resistant Escherichia coli ATCC BAA-196
<0.20 <0.21
7.50
50.35 26.56 29.96 30.73 63.88
25.17 26.56 29.96 15.39 63.88
4.89 100.70
6.64 29.96
7.67 63.88
7.67 <0.99
Multi-drug resistant Pseudomonas aeruginosa ATCC BAA-2111 <0.61
<0.79 <0.83 <0.94

ACCEPTED MANUSCRIPT
Highlights:
•
N-arylsulfonylindoles containing an aminoguanidine showed excellent inhibitory

activity against multidrug-resistant strains
•
•
•
Anti-cancer activity was also confirmed with a high selectivity
Resistance of strains S. aureus and E. coli toward 6d is not easily developed
Molecular docking studies suggested the FabH was involved in the the
antibacterial activity of 6d