Synthesis and bacteriostatic activities of bis(Thiourea) derivatives with variable Chain Length

Article abstract of DOI:10.1155/2016/2739832

A series of 1,4-bis(decoxyphenyl)carbamothioyl-Terephthalamide derivatives was successfully synthesised by reaction of benzene- 1,4-dicarbonyl isothiocyanate intermediates with long alkyl chain. The alkylation was performed via Williamson etherification o

Full text of DOI:10.1155/2016/2739832

Hindawi Publishing Corporation
Journal of Chemistry
Volume 2016, Article ID 2739832, 7 pages
http://dx.doi.org/10.1155/2016/2739832
Research Article
Synthesis and Bacteriostatic Activities of
Bis(thiourea) Derivatives with Variable Chain Length
Ainaa Nadiah Abd Halim and Zainab Ngaini
Department of Chemistry, Faculty of Resources Science and Technology, Universiti Malaysia Sarawak,
94300 Kota Samarahan, Sarawak, Malaysia
Correspondence should be addressed to Zainab Ngaini; nzainab@unimas.my
Received 1 September 2016; Revised 18 November 2016; Accepted 24 November 2016
Academic Editor: Radhey Srivastava
Copyright © 2016 A. N. Abd Halim and Z. Ngaini. is is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
A series of 1,4-bis(decoxyphenyl)carbamothioyl-terephthalamide derivatives was successfully synthesised by reaction of benzene-
1,4-dicarbonyl isothiocyanate intermediates with long alkyl chain. e alkylation was performed via Williamson etherification
of 4-acetamidophenol with bromoalkanes. e synthesised bis(thiourea) derivatives differed in the chain length, C H , where
ꢀ
2ꢀꢁ+
+
ꢀ ꢁ =0, 12, and 14. e structures of all compounds were characterised by elemental CHN analysis, IR, H, and +3C NMR
spectroscopies. Bacteriostatic activities of bis(thiourea derivatives which consisted of two folds of N-H, C=O, and C=S and long
alkyl chain substituents were carried out against Gram-negative bacteria (Escherichia coli, ATCC 25922) via turbidimetric kinetic
method. Bis(thiourea) derivatives with ꢀ ꢁ =0 and ꢀ ꢁ =2 displayed excellent activity against E. coli with MIC of 135 ꢂg/mL and
145 ꢂg/mL, respectively, while bis(thiourea) derivatives with ꢀ ꢁ =4 acted as cutoff point with no antibacterial properties. Similar
trend was observed in binding affinity to the active site of enoyl ACP reductase (FabI), which demonstrated binding free energy of
−5.3 Kcal/mol and −4.9 and −4.8 Kcal/mol, respectively.
1. Introduction
in thiourea moieties which can be easily protonated under
acidic condition and reacted with the carboxyl and phosphate
groups of the bacterial surface and thus enhanced the activity
[16].
Incorporation of alkyl chain as substituents in thiourea
derivatives has been reported for significant biological prop-
erties [17, 18]. e presence of long alkyl chains was reported
to enhance the biological activity of thiourea derivatives [19].
Alkyl chains have the ability to increase lipophilicity and pro-
mote the ability of the compound to disrupt microorganism
cell wall [20–22].
iourea which is also known as thiocarbamide is a white
crystalline solid compound that consists of sulphur and nitro-
gen atoms. iourea moiety has become intensely synthesised
due to its ability to undergo structural modifications [1]. e
existing of two units of reactive primary amine groups has
made thiourea a suitable precursor for a synthesis of many
new compounds [2]. iourea derivatives are well known to
display a broad spectrum of applications in pharmaceutical
industry due to their biological properties such as antipara-
sitic [3], anticancer [4], antioxidant [5, 6], antibacterial [7–
10], antifungal [11], and anti-HIV [12, 13] properties.
e synthesis and antibacterial studies of monothiourea
derivative are progressing at the considerable rate while
bis(thiourea) compounds are relatively less reported [14]. e
presence of two or more thiourea moieties, for example,
bis(thiourea), was envisaged to possess better antibacterial
activity [15]. is is due to the ability of C=S and N-H groups
In this paper, we report on the synthesis of novel 1,4-
bis(decoxyphenyl)carbamothioyl-terephthalamide derivati-
ves (2a–c) bearing alkyl chain of different length (C , C ,
+0
+2
and C ). e compounds were demonstrated for antibac-
+4
terial activities against Gram-negative bacteria (Escherichia
coli, ATCC 25922) where the effects of different length of alkyl
chains were evaluated.

2
Journal of Chemistry
2. Materials and Methods
4-(Tetradecyloxy)benzenamine (1c). 4-(Tetradecyloxy)benze-
namine (1c) was obtained from N-(4-(tetradecyloxy)phenyl)
acetamide (3.50 g, 10 mmol). (2.80 g, 91%) as off-white solid,
m.p: 142-143∘C ]max (KBr/cm−+) 3467 (NH), 2915 (CH), 1510
(Ar-C), 1169 (C-N), 1039 (C-O). ꢃ (500 MHz, DMSO-d )
Benzene-1,4-dioylchloride was acquired from Acros Organ-
ics. Potassium thiocyanate, 1-bromodecane, 1-bromododec-
ane, and 1-bromotetradecane were purchased from Merck
kGaa. e solvents were dried and distilled before being
used under nitrogen as follows: acetone was distilled over
potassium permanganate and acetonitrile was distilled over
calcium hydride. All the reagents were used as received
without any further purification.
H
6
0.85 (3H, t, 1x CH ), 1.23–1.98 (24H, m, 12x CH ), 3.94 (2H,
3
2
t, 1x CH ), 7.01 (2H, d, ꢄ ꢁ 9.55 Hz, Ar-H), 7.31 (2H, d,
2
ꢄ ꢁ 8.6 Hz, Ar-H), 10.25 (2H, s, 1x NH). ꢃ (125 MHz, DMSO-
d ) 14.0, 22.1, 25.5, 28.6, 28.7, 28.8, 29.0, C30.7, 31.3, 67.8, 115.3,
6
124.1, 124.3, 158.1.
Physical Measurement. Melting points were determined by
using Stuart SMP3 melting point apparatus and uncorrected.
e elemental CHNS analysis was provided by Universiti
Teknologi MARA (UiTM) using ermo Scientific6 FLASH
2000 CHNS/O Analyzers. Infrared (IR) spectra (]/cm−+)
were recorded as KBr pellets on Perkin Elmer ermoscien-
tific Smart Omni Transmission Nicolet IS10 Fourier Trans-
form Infrared Spectrometer (FTIR). +H NMR and +3C NMR
spectra were recorded using JEOL ECA 500 spectrometer at
500 MHz (+H) and 125 MHz (+3C) with the chemical shifs ꢃ
2.2. Synthesis of 1,4-bis(decoxyphenyl)carbamothioyl-tereph-
thalamide Derivatives (2a–2c). A solution of benzene-1,4-
dioylchloride in dry acetone (20 mL) was added into a sus-
pension of potassium thiocyanate in dry acetone (20 mL). e
mixture was stirred at room temperature to form precipitate.
e mixture was filtered and the white KCl was removed.
e filtrate was used directly in next step. Triethylamine was
added dropwise to benzenamine derivatives (1a–1c) in dry
acetone (20 mL). e mixture was added to the filtrate. e
reaction mixture was stirred at room temperature for 4 h and
filtered. e crude solid was recrystallised in DMF : MeOH
(1 : 1) mixture. e preparation of 2a–2c with benzenamine
derivatives 1a–1c (g, mmol) and yield is shown as follows.
(ppm) reported relative to DMSO-d as standards.
6
2.1. Synthesis of Benzenamine Derivatives (1a–1c). A mixture
of 4-acetamidophenol, bromoalkane, and K CO in acetone
2
3
N1,N4-bis[(4-Decoxyphenyl)carbamothioyl]terephthalamide
(2a). N1,N4-bis[(4-decoxyphenyl)carbamothioyl]tereph-tha-
lamide (2a) was obtained from 4-(decyloxy)benzenamine
1a (0.25 g, 1 mmol). (0.26 g, 69%) as bright yellow, m.p:
199-200∘C; (Found: C, 67.46; H, 7.76; N, 7.49; S, 8.52.
C H N O S , Requires C, 67. 5; H, 7. 8; N, 7. 5; S, 8. 6%); ]max
(20 mL) was heated at reflux constant stirring for 48 h. e
reaction mixture was cooled to room temperature and taken
to dryness. e solid was stirred for 1 h with 50 mL of 2%
sodium hydroxide and filtered and then heated at reflux for
2 h in ethanol : concentrated hydrochloric acid (1 : 1) ratio
(10 mL : 10 mL) and allowed to cool to room temperature.
Water (20 mL) was added to the reaction mixture and the
layers were separated. e aqueous layer was extracted with
dichloromethane (20 mL). e organic layer was separated,
42 58
4
4
2
(KBr/cm−+) 3393 (NH), 2922 (CH), 1668 (C=O amide), 1531
(Ar-C), 1244 (C=S), 1144 (C-N), 1116 (C-O). ꢃ (500 MHz,
H
CDCl ) 0.88 (6H, t, 2x CH ), 1.28–1.80 (32H, m, 16x CH ),
3
3
2
3.97 (4H, t, 2x CH ), 6.94 (4H, d, J = 9.15 Hz, Ar-H), 7.56
2
dried over MgSO , and filtered and solvent was removed in
4
(4H, d, J = 9.2 Hz, Ar-H), 8.05 (4H, s, Ar-H), 9.14 (2H, s, 2x
NH), 12.25 (2H, s, 2x NH). ꢃ (125 MHz, CDCl ) 14.2, 22.8,
vacuo to afford intermediate compounds 1a–1c with yields as
C
3
follows.
26.1, 29.3, 29.4, 29.5, 29.7, 32.0, 68.4, 114.8, 125.9, 128.4, 158.2,
165.5, 178.2.
4-(Decyloxy)benzenamine (1a). 4-(Decyloxy)benzenamine
(1a) was obtained from N-(4-(decyloxy)phenyl)acetamide
(2.92 g, 10 mmol). (2.02 g, 81%) as milky white solid, m.p: 136-
137∘C ]max (KBr/cm−+) 3467 (NH), 2917 (CH), 1509 (Ar-C),
N1,N4-bis[(4-Dodecoxyphenyl)carbamothioyl]terephthalamide
(2b). N1,N4-bis[(4-dodecoxyphenyl)carbamothioyl]tereph-
thalamide (2b) was obtained from 4-(dodecyloxy)benzen-
amine 1b (0.29 g, 1 mmol). (0.24 g, 60%) as light yellow solid,
m.p: 202-203∘C; (Found: C, 68.78; H, 8.28; N, 7.03; S, 8.03.
C H N O S , Requires C, 68.8; H, 8.3; N, 7.0; S, 8.0%); ]max
1169 (C-N), 1028 (C-O). ꢃ (500 MHz, CDCl ) 0.89 (3H, t, 1x
CH ), 1.27–1.72 (16H, m, H8x CH ), 3.82 (2H, t, 1x CH ), 6.71
3
3
2
2
(2H, d, ꢄ ꢁ 7.65 Hz, Ar-H), 7.33 (2H, d, J = 8.6 Hz, Ar-H),
10.10 (2H, s, 1x NH). ꢃ (125 MHz, CDCl ) 14.2, 22.8, 26.1,
46 66
4
4
2
(KBr/cm−+) 3397 (NH), 2921 (CH), 1668 (C=O amide), 1532
C
3
29.3, 29.4, 29.6, 29.7, 32.0, 68.3, 115.4, 122.3, 124.7, 159.2.
(Ar-C), 1245 (C=S), 1145 (C-N), 1117 (C-O). ꢃ (500 MHz,
H
CDCl ) 0.88 (6H, t, 2x CH ), 1.26–1.81 (40H, m, 20x CH ),
3
3
2
4-(Dodecyloxy)benzenamine (1b). 4-(Dodecyloxy)benzena-
mine (1b) was obtained from N-(4-(dodecyloxy)phenyl)acet-
amide (3.20 g, 10 mmol). (1.92 g, 69%) as light brown solid,
m.p: 139-140∘C ]max (KBr/cm−+) 3467 (NH), 2916 (CH), 1509
(Ar-C), 1169 (C-N), 1028 (C-O). ꢃ (500 MHz, DMSO-d )
3.97 (4H, t, 2x CH ), 6.95 (4H, d, ꢄ ꢁ 9.=5 Hz, Ar-H), 7.56
2
(4H, d, ꢄ ꢁ 9.=5 Hz, Ar-H), 8.06 (4H, s, Ar-H), 9.10 (2H, s, 2x
NH), 12.24 (2H, s, 2x NH). ꢃ (125 MHz, CDCl ) 13.1, 21.5,
24.9, 28.1, 28.2, 28.4, 28.5, 30.C8, 67.1, 113.4, 125.0, 127.7, 129.6,
3
135.1, 156.6, 166.5, 178.3.
H
6
0.84 (3H, t, 1x CH ), 1.23–1.68 (20H, m, 10x CH ), 3.94 (2H,
3
2
t, 1x CH ), 7.00 (2H, d, ꢄ ꢁ 8.6 Hz, Ar-H), 7.31 (2H, d, ꢄ ꢁ
N1,N4-bis[(4-Tetradecoxyphenyl)carbamothioyl]terephthala-
mide (2c). N1,N4-bis[(4-tetradecoxyphenyl)carbamothioyl]-
terephthalamide (2c) was obtained from 4-(tetradecyloxy)-
benzenamine 1c (0.31 g, 1 mmol). (0.20 g, 46%) as yellow
2
8.6 Hz, Ar-H), 10.29 (2H, s, 1x NH). ꢃ (125 MHz, DMSO-d )
C
6
14.0, 22.1, 25.5, 28.6, 28.7, 28.8, 29.0, 29.1, 31.3, 67.8, 115.3, 123.9,
124.5, 158.2.

Journal of Chemistry
3
O
(i) R-Br, K2CO3, acetone,
2% NaOH
OH
O
O
R
Cl
+
(ii) CH3CH2OH, Conc. HCl
Cl
N
H
H2N
O
1a–c
KSCN, TEA
acetonitrile, r.t
O
R
S
O
N
N
H
H
H
N
H
N
S
O
R
O
2a–c
R, 2a = C10H21
2b = C12H25
2c = C14H29
Scheme 1: Synthesis of bis(thiourea) derivatives.
solid, m.p: 208–210∘C; (Found: C, 69.98; H, 8.72; N, 7.36;
S, 7.49. C H N O S , Requires C, 69.9; H, 8.7; N, 7.4; S,
with AutoDock Tools 1.5.6 [25] prior to docking with Auto-
˚
Dock Vina program. e cubic grid box of 60 A size (ꢈ, ꢉ,
50 74
4
4
2
7. 5%); ]max (KBr/cm−+) 3397 (NH), 2918 (CH), 1669 (C=O
Amide), 1531 (Ar-C), 1244 (C=S), 1148 (C-N), 1117 (C-O).
ꢃ (500 MHz, CDCl ) 0.88 (6H, t, 2x CH ), 1.26–1.80 (48H,
and ꢊ) with a spacing of 0.375 A were centred on the active
˚
site of the protein. e X-ray crystal structure of the enzyme
enoyl ACP reductase (FabI) of E. coli (PDB entry: 1C14) was
retrieved from Protein Data Bank (http://www.rcsb.org/pdb/
home/home.do) [26].
H
3
3
m, 24x CH ), 3.98 (4H, t, 2x CH ), 6.95 (4H, d, ꢄ ꢁ 8.6 Hz,
2
2
Ar-H), 7.56 (4H, d, ꢄ ꢁ 8.6 Hz, Ar-H), 8.06 (4H, s, Ar-H),
9.05 (2H, s, 2x NH), 12.23 (2H, s, 2x NH). ꢃ (125 MHz,
C
CDCl ) 14.2, 22.8, 26.1, 29.3, 29.5, 29.7, 29.8, 32.0, 68.3, 114.8,
3
3. Results and Discussion
125.9, 128.4, 130.1, 136.2, 158.2, 165.6, 178.0.
3.1. Chemistry. e synthesis of bis(thiourea) 2a–2c involved
multiple steps reactions. e reaction involved alkylation of
4-acetamidophenol with a series of bromoalkanes (C , C ,
2.3. Antibacterial Screening. e synthesised bis(thiourea)
compounds 2a–2c were screened for the antibacterial activ-
ities against Gram-negative bacteria E. coli and employing
turbidimetric kinetic method. e bacteria were cultured on
Luria-Bertani (LB) agar for 24 h at 37∘C. e inoculums were
prepared by allowing bacteria to grow on media containing
nutrient broth at 37∘C with permanent stirring at 250 rpm
for 18 h. e inoculums (0.2 mL) were inoculated with 10 mL
of culture medium (with increasing concentration of the
compounds dissolved in propanol). e mixture was shaken
at 180 rpm at 37∘C. Inoculums with propanol were used as
a control. Aliquots of each replicates were taken at every
1 h interval for 6 h. e transmittances (ꢅ) were recorded
using a UV-Visible spectrophotometer (Optima SP-300). e
antibacterial activities were determined by plotting a graph
of ln ꢆꢇ versus time. e ln ꢆꢇ is defined as transmittance
value, which represents the number colony forming units
(CFU) mL−+ for bacteria versus time following expressions:
E. coli ln ꢆꢇ = 27.1–8.56ꢅ [23].
+0
+2
and C ) in the presence of K CO followed by hydrolysis
+4
2
3
to form benzenamine derivatives (intermediate) 1a–1c. e
reaction of intermediate 1a–1c prior to deprotonation by TEA
for 3 h at room temperature gave bis(thiourea) 2a–2c with
moderate yields of 46–69%. e synthesis route of 2a–2c is
illustrated in Scheme 1.
e IR spectra showed the successful formation of 2a–2c
with the presence of frequencies at 3397–3393 cm−+ attributed
to VNH band. e absorption attributed to aliphatic car-
bon chain was observed at 2922–2918 cm−+, while strong
absorption band at 1669–1668 cm−+ corresponded to VC=O
amide. e aromatic ring was represented by the absorption
bands at 1532–1531 cm−+. e VC=S absorption bands were
observed at 1245–1244 cm−+ which confirmed the formation
of thiourea in the compounds [27]. e VC-N absorption band
was observed at 1148–1144 cm−+ [28].
Further confirmation of the formation of 2a–2c was
+
supported by H and +3C NMR spectroscopies. e two
2.4. Molecular Docking. e docking studies on 2a–2c were
carried out using AutoDock Vina 1.1.2 program [24]. e
polar hydrogens of the compounds and protein were added
singlets attributed to CSNH and CONH peak were observed
at 12.25–12.23 ppm and 9.14–9.05 ppm, respectively, which
indicated the formation of thiourea [7]. e peak of CSNH

4
Journal of Chemistry
2b
2a
26
24
22
20
26
24
22
20
0
1
2
3
4
5
6
0
1
2
3
4
5
6
Time (h)
Time (h)
80g/mL
100 g/mL
80g/mL
100 g/mL
C(−)
C(−)
C(+)
C(+)
50g/mL
50g/mL
(a)
(b)
2c
26
24
22
20
0
1
2
3
4
5
6
Time (h)
80g/mL
100 g/mL
C(−)
C(+)
50g/mL
(c)
Figure 1: Growth of E. coli in media containing compounds: (a) 2a, (b) 2b, and (c) 2c.
was at higher chemical shif due to deshielding effect [18].
Multiple peaks observed at 8.06–6.94 ppm were assigned to
aromatic protons. e resonance as triplet at 3.97 ppm was
attributed to -OCH while alkyl chain (-CH ) was repre-
activities using turbidimetric kinetic method. Compounds
2a–2c were examined at the concentration of 50 ꢂg/mL,
80 ꢂg/mL, and 100 ꢂg/mL against Gram-negative bacteria E.
coli ATCC 25922. e result for an antibacterial assay for each
compound is shown in Figure 1. e results were represented
by graphs of ln ꢆꢇ versus time (ꢇ) where ln ꢆꢇ, defined as
transmittance value, corresponded to the number of colony
forming units (CFU) mL−+ for E. coli versus time following
expression ln ꢆꢇ = 27.1–8.56ꢅ [23]. Compounds 2a and 2b
showed excellent inhibition against E. coli compared to 2c.
2
2
sented by the peaks at 0.88–1.81 ppm.
e resonance of +3C NMR at 178.3–178.2 ppm and 166.4–
165.5 ppm was attributed to C=S and C=O, respectively.
e multiple resonances observed at 158.2–113.4 ppm were
assigned to aromatic carbons in the compound. e -OCH
2
was observed at 68.4–67.1 ppm while -CH was observed as
2
multiple resonances due to the number of carbon chains at
e minimum inhibitory concentration (MIC) was also
performed by extrapolating the concentration at the zero
growth rate of E. coli (ꢂ ꢁ 0) [30]. MIC is the lowest concen-
tration of the antimicrobial agent that inhibits the develop-
ment of visible growth afer overnight incubation and use to
confirm the resistance of microorganisms to the antibacte-
rial agent [31]. Propanol was used as negative control and
32.0–13.1 ppm. e -OCH peak appeared at higher frequency
2
compared to alkyl -CH resonance due to downfield effect as
2
it has been attached to higher electronegative atom (oxygen)
[29].
3.2. Antibacterial Activity and Docking. e synthesised bis-
(thiourea) derivatives 2a–2c were screened for antibacterial

Journal of Chemistry
5
2
1.5
1
0.5
0
0
40
80
120
160
Concentration (g/mL)
−0.5
C(+)
2a
2b
2c
Figure 2: Minimum inhibitory concentration of 2a–2c against E. coli.
(a)
(b)
(c)
Figure 3: e molecular binding of (a) 2a, (b) 2b, and (c) 2c with enzyme enoyl ACP reductase (FabI) of E. coli.
ampicillin as positive control. e MIC of 2a–2c is shown in
Figure 2.
comparison to 2a and 2b, 2c which has the longest carbon
chain could have imitated the molecule in the lipid bilayer
of organism and afforded less disruption in the bacteria
membrane [33].
e MIC data obtained showed that both 2a and 2b
exhibited excellent antibacterial activities with MIC values
of 135 ꢂg/mL and 145 ꢂg/mL, respectively. e MIC value
For the further understanding of the interactions between
of ampicillin was observed at 108 ꢂg/mL. e MIC values
less than 200 ꢂg/mL can be suggested for pharmacological
purposes [32]. It was believed that the antibacterial activities
of 2a and 2b were due to the lipophilic character of the long
alkyl chain which has the ability to disrupt microorganism
cell wall [20, 21].
Gram-negative bacteria E. coli and bis(thiourea) derivatives
2a–2c as potential antibacterial agents, 2a–2c were interacted
via docking to the active site of the enzyme enoyl ACP
reductase (FabI) of E. coli (PDB entry: 1C14) using AutoDock
Vina 1.1.2 program [24–26]. e binding interaction for 2a–2c
is shown in Figure 3.
However, the antibacterial activities of the compounds
decreased as the alkyl chains increased. Compound 2c with
e binding affinity of 2a–2c was evaluated based on
binding free energies (Δꢋꢂ, Kcal/mol) [34]. Based on the
binding model depicted in Figure 3, 2a possessed the highest
C
alkyl chains, for instance, showed the MIC values of
+4
>200 ꢂg/mL. is phenomenon was due to the cutoff effect
where the compound demonstrated a parabolic effect as
the alkyl chain lengths increased from 14 to 16 [20]. In
binding affinity with a binding free energy of −5.3 Kcal/mol
followed by 2b and 2c with −4.9 and −4.8 Kcal/mol, respec-
tively. Compound 2a is strongly bound to enzyme enoyl ACP

6
Journal of Chemistry
reductase (FabI) of E. coli through ꢌ-ꢌ bond interactions (yel-
low colour cylindrical wireframe) with hydrophobic pockets
of Phe 1231 and His 1246. e hydrophobic interaction
between phenyl rings has increased the lipophilicity of the
compound [32]. Other basic residues such as Asn 1227, Ser
1228, Asp 1224, Val 1247, Gly 1249, and Ile 1216 (Figure 3)
were observed in close proximity to compound 2a, which
suggested that a strong electrostatic interaction was also
involved in the binding process [35]. On the other hand, the
increase of carbon chain in 2b and 2c was accountable for
lesser binding affinity [36].
[5] C. Saturnino, M. D’Auria, N. Paesano et al., “Antioxidant activity
of thioureidic derivatives I,” Il Farmaco, vol. 58, no. 9, pp. 823–
828, 2003.
[6] P. Venkatesh and S. N. Pandeya, “Synthesis and anti-oxidant
activity of some N-(anilinocarbonothioyl) benzamide and het-
erocyclic based thiourea derivatives,” International Journal of
ChemTech Research, vol. 1, no. 3, pp. 733–741, 2009.
[7] P. B. Kaswala, K. H. Chikhalia, N. K. Shah, D. P. Patel, D. H. Patel,
and G. V. Mudaliar, “Design, synthesis and antimicrobial eva-
luation of s-triazinyl urea and thiourea derivatives,” Arkivoc, vol.
2009, no. 11, pp. 326–335, 2009.
[8] Z. Ngaini, M. A. Mohd Arif, H. Hussain, E. S. Mei, D. Tang,
and D. H. A. Kamaluddin, “Synthesis and antibacterial activity
of acetoxybenzoyl thioureas with aryl and amino acid side
Chains,” Phosphorus, Sulfur and Silicon and the Related Ele-
ments, vol. 187, no. 1, pp. 1–7, 2012.
[9] W. S. H. Wan Zullkiplee, A. N. Abd Halim, Z. Ngaini, M. A.
Mohd Ariff, and H. Hussain, “Bis-iourea bearing aryl and
amino acids side chains and their antibacterial activities,” Phos-
phorus, Sulfur and Silicon and the Related Elements, vol. 189, no.
6, pp. 832–838, 2014.
[10] N. I. M. Halim, K. Kassim, A. H. Fadzil, and B. M. Yamin, “Syn-
thesis, characterisation and antibacterial studies of Cu(II) com-
plexes thiourea,” Malaysian Journal of Analytical Sciences, vol.
16, no. 1, pp. 56–61, 2012.
[11] J. Wu, Q. Shi, Z. Chen, M. He, L. Jin, and D. Hu, “Synthesis and
bioactivity of pyrazole acyl thiourea derivatives,” Molecules, vol.
17, no. 5, pp. 5139–5150, 2012.
[12] F. M. Uckun, C. Mao, S. Pendergrass et al., “N-[2-(4-methyl-
phenyl)ethyl]-N’-[2-(5-bromopyridyl)]-thiourea as a potent
inhibitor of NNRTI-resistant and multidrug-resistant human
immunodeficiency virus type 1,” Antiviral Chemistry and Che-
motherapy, vol. 11, no. 2, pp. 135–140, 2000.
4. Conclusions
Novels bis(thiourea) derivatives 2a–2c were successfully syn-
thesised and evaluated for antibacterial activities against E.
coli. e MIC data obtained showed that 2a and 2b with
ꢀ ꢁ =0 and ꢀ ꢁ =2 exhibited excellent antibacterial activities
with MIC values of 135 ꢂg/mL and 145 ꢂg/mL, respectively.
e increase of carbon chain has decreased the antibacterial
activities. Further studies on the correlation of the molec-
ular structure and binding affinity via molecular docking
interaction study revealed the binding interaction of 2a–2c
with enzyme enoyl ACP reductase (FabI) of E. coli, in a
similar trend to that of the biological activities. Based on the
molecular docking and antibacterial assay study, it can be
suggested that 2a is a potential antibacterial agent for phar-
maceutical applications.
Competing Interests
e authors declare that there is no conflict of interests
regarding the publication of this paper.
[13] I. Ku¨c¸u¨kgu¨zel, E. Tatar, S¸. G. Ku¨c¸u¨kgu¨zel, S. Rollas, and E. De
Clercq, “Synthesis of some novel thiourea derivatives obtained
from 5-[(4-aminophenoxy)methyl]-4-alkyl/aryl-2,4-dihydro-
3H-1,2,4-triazole-3-thiones and evaluation as antiviral/anti-
HIV and anti-tuberculosis agents,” European Journal of Medi-
cinal Chemistry, vol. 43, no. 2, pp. 381–392, 2008.
[14] N. I. M. Halim, K. Kassim, A. H. Fadzil, and B. M. Yamin, “Syn-
thesis, characterization and antibacterial studies of benzoylth-
iourea derivatives,” IPCBEE, vol. 14, pp. 55–59, 2011.
Acknowledgments
e authors would like to acknowledge Universiti Malaysia
Sarawak and Ministry of Education for research funds
F07(DPP42)/1262/2015(17) and FRGS/E14099/F07/69/1298/
2015(15).
[15] M. O. Uwaisulqarni and M. B. Yamin, “Synthesis and structural
study of bis-thiourea moieties with aromatic linkers,” in Pro-
ceedings of the 11th International Annual Symposium on Sustain-
ability Science and Management, Universiti Malaysia Tereng-
ganu, 2012.
[16] Z. Zhong, R. Xing, S. Liu, L. Wang, S. Cai, and P. Li, “Synthesis
of acyl thiourea derivatives of chitosan and their antimicrobial
activities in vitro,” Carbohydrate Research, vol. 343, no. 3, pp.
566–570, 2008.
[17] M. Huang, Y. Sun, W. Yang et al., “[583] ACH-806: a potent
inhibitor of HCV replication with a novel mechanism of action,”
Journal of Hepatology, vol. 46, p. S221, 2007.
[18] S. Saeed, N. Rashid, P. G. Jones, M. Ali, and R. Hussain, “Synthe-
sis, characterization and biological evaluation of some thiourea
derivatives bearing benzothiazole moiety as potential antimi-
crobial and anticancer agents,” European Journal of Medicinal
Chemistry, vol. 45, no. 4, pp. 1323–1331, 2010.
References
[1] M. Ili, M. Bucos, F. Dumitracu, and V. Cˆırcu, “Mesomorphic
behaviour of N-benzoyl-Nꢍ-aryl thioureas liquid crystalline
compounds,” Journal of Molecular Structure, vol. 987, no. 1–3,
pp. 1–6, 2011.
[2] S. Murru, C. B. Singh, V. Kavala, and B. K. Patel, “A convenient
one-pot synthesis of thiazol-2-imines: application in the con-
struction of pifithrin analogues,” Tetrahedron, vol. 64, no. 8, pp.
1931–1942, 2008.
[3] J. Mu¨ller, C. Limban, B. Stadelmann et al., “ioureides of 2-
(phenoxymethyl) benzoic acid 4-R substituted: a novel class of
anti-parasitic compounds,” Parasitology International, vol. 58,
no. 2, pp. 128–135, 2009.
[4] J. C. Shing, J. W. Choi, R. Chapman et al., “A novel synthetic 1,3-
phenyl bis-thiourea compound targets microtubule polymer-
ization to cause cancer cell death,” Cancer Biology & erapy,
vol. 15, no. 7, pp. 895–905, 2014.
[19] N. S. Reddy, A. S. Rao, M. A. Chari, V. R. Kumar, V. Jyothy, and V.
Himabindu, “Synthesis and antibacterial activity of sulfonamide

Journal of Chemistry
7
derivatives at C-8 alkyl chain of anacardic acid mixture isolated
from a natural product cashew nut shell liquid (CNSL),” Journal
of Chemical Sciences, vol. 124, no. 3, pp. 723–730, 2012.
[34] P.-C. Lv, H.-Q. Li, J. Sun, Y. Zhou, and H.-L. Zhu, “Synthesis and
biological evaluation of pyrazole derivatives containing thiou-
rea skeleton as anticancer agents,” Bioorganic and Medicinal
Chemistry, vol. 18, no. 13, pp. 4606–4614, 2010.
[35] Y. He, Y. Wang, L. Tang et al., “Binding of puerarin to human
serum albumin: a spectroscopic analysis and molecular dock-
ing,” Journal of Fluorescence, vol. 18, no. 2, pp. 433–442, 2008.
[20] C. R. Birnie, D. Malamud, and R. L. Schnaare, “Antimicrobial
evaluation of N-alkyl betaines and N-alkyl-N, N-dimethyl-
amine oxides with variations in chain length,” Antimicrobial
Agents and Chemotherapy, vol. 44, no. 9, pp. 2514–2517, 2000.
[21] K. D. Park, Y. S. Park, S. J. Cho et al., “Antimicrobial activity of 3-
O-Acyl-(-)-epicatechin and 3-O-Acyl-(+)- catechin derivatives,”
Planta Medica, vol. 70, no. 3, pp. 272–276, 2004.
[22] Z. Ngaini, S. M. Haris Fadzillah, and H. Hussain, “Synthesis and
antimicrobial studies of hydroxylated chalcone derivatives with
variable chain length,” Natural Product Research, vol. 26, no. 10,
pp. 892–902, 2012.
[36] M. Kvasnica, J. Oklestkova, V. Bazgier, L. Rarova, K. Berka,
and M. Strnad, “Biological activities of new monohydroxylated
brassinosteroid analogues with a carboxylic group in the side
chain,” Steroids, vol. 85, pp. 58–64, 2014.
[23] N. B. Pappano, O. N. P. Centorbi De, and F. H. Ferretti, “Deter-
mination of the responsible molecular zone for the chalcones
bacteriostatic activity,” Revista de Microbiologia, vol. 25, no. 3,
pp. 168–174, 1994.
[24] O. Trott and A. J. Olson, “Sofware news and update AutoDock
Vina: improving the speed and accuracy of docking with a new
scoring function, efficient optimization, and multithreading,”
Journal of Computational Chemistry, vol. 31, no. 2, pp. 455–461,
2010.
[25] G. M. Morris, H. Ruth, W. Lindstrom et al., “AutoDock4 and
AutoDockTools4: automated docking with selective receptor
flexibility,” Journal of Computational Chemistry, vol. 30, no. 16,
pp. 2785–2791, 2009.
[26] S. George, M. B. Ramzeena, S. V. Ram, S. K. Selvaraj, S. Rajan,
and T. K. Ravi, “Design, docking, synthesis and anti E. coli
screening of novel thiadiazolo thiourea derivatives as possible
inhibitors of enoyl ACP reductase (FabI) enzyme,” Bangladesh
Journal of Pharmacology, vol. 9, no. 1, pp. 49–53, 2014.
[27] A. Saeed, N. Abbas, Z. Ashraf, and M. Bolte, “Synthesis, chara-
cterization and antibacterial activity of new 1, 2-and 1, 4-bis
(N’-substituted thioureido) benzene derivatives,” South African
Journal of Chemistry, vol. 66, pp. 273–278, 2013.
[28] A. Saeed, H. Rafique, A. Hameed, and S. Rasheed, “Synthesis
and antibacterial activity of some new 1-aroyl-3-(substituted-
2-benzothiazolyl)thioureas,”Pharmaceutical Chemistry Journal,
vol. 42, article 191, 2008.
[29] M. K. Rauf, Imtiaz-ud-Din, A. Badshah et al., “Synthesis, struc-
tural characterization and in vitro cytotoxicity and anti-bacte-
rial activity of some copper (I) complexes with N, Nꢍ-dis-
ubstituted thioureas,” Journal of Inorganic Biochemistry, vol. 103,
no. 8, pp. 1135–1144, 2009.
[30] M. De Los Angeles Alvarez, V. E. P. Zarelli, N. B. Pappano, and
N. B. Debattista, “Bacteriostatic action of synthetic polyhydrox-
ylated chalcones against Escherichia coli,” Biocell, vol. 28, no. 1,
pp. 31–34, 2004.
[31] D. Greenwood, R. Slack, and J. Peutherer, “Medical microbiol-
ogy,” in A Guide to Microbial Infections: Pathogenesis, Immunity,
Laboratory Diagnosis and Control, ELST Publishers, Edinburgh,
UK, 15th edition, 1997.
[32] H. Arslan, N. Duran, G. Borekci, C. K. Ozer, and C. Akbay,
“Antimicrobial activity of some thiourea derivatives and their
nickel and copper complexes,” Molecules, vol. 14, no. 1, pp. 519–
527, 2009.
ˇ
[33] F. Dev´ınsky, A. Kopecka-Leitmanova´, F. Serˇsenˇ, and P. Balgavy´,
“Cut-off effect in antimicrobial activity and in membrane per-
turbation efficiency of the homologous series of N,N-dimethy-
lalkylamine oxides,” Journal of Pharmacy and Pharmacology,
vol. 42, no. 11, pp. 790–794, 1990.

International Journal of
Advances in
Organic Chemistry
International
International Journal of
International Journal of
Photoenergy
Medicinal Chemistry
Analytical Chemistry
Physical Chemistry
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
Volume 2014
International Journal of
Carbohydrate
Chemistry
Journal of
Quantum Chemistry
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
http://www.hindawi.com
Volume 2014
Volume 2014
Submit your manuscripts at
http://www.hindawi.com
Journal of
The Scientific
Analytical Methods
in Chemistry
World Journal
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
http://www.hindawi.com
Volume 2014
Volume 2014
International Journal of
Journal of
Journal of
International Journal of
Bioinorganic Chemistry
Spectroscopy
Inorganic Chemistry
Electrochemistry
Applied Chemistry
and Applications
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
Journal of
Journal of
International Journal of
Chromatography
Journal of
Theoretical Chemistry
Research International
Catalysts
Chemistry
Spectroscopy
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
Volume 2014
Volume 2014
Volume 2014