Synthesis of 3-chloro-4-fluorophenyl-3,4-dichlorophenyl substituted thiocarbamide derivatives as potential antitubercular agents

Article abstract of DOI:10.1007/s00044-014-1059-0

A series of dihalosubstituted thiocarbamide derivatives (5a-e, 6a-e, 7a-e, and 8a-e) were synthesized as antitubercular agents. The structures of dihalosubstituted thiocarbamide derivatives were established on the basis of IR, ¹H, ¹³C NMR, and mass spectral data. All the compounds were tested in vitro for antimycobacterial activity against Mycobacterium tuberculosis (ATCC-25177) by well-diffusion method and MIC by serial dilution method. Results of the antitubercular screening revealed that some of the compounds showed moderate to good antitubercular activity. Of all the compounds tested, two derivatives viz., 8d and 8e expressed MIC of 25 μg/ml, and one compound 7e showed MIC of 12.5 μg/ml against M. tuberculosis (ATCC-25177). Graphical Abstract: [Figure not available: see fulltext.]

Full text of DOI:10.1007/s00044-014-1059-0

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2015) 24:334–343
DOI 10.1007/s00044-014-1059-0
ORIGINAL RESEARCH
Synthesis of 3-chloro-4-fluorophenyl-3,4-dichlorophenyl
substituted thiocarbamide derivatives as potential
antitubercular agents
M. Faiz Arshad
Allam A. Hassan
•
Suresh Kumar
Ahmed Elkerdasy
•
Abdulmohsen H. Al Rohaimi
Neeraj Upmanyu
•
•
•
Received: 18 December 2013 / Accepted: 22 May 2014 / Published online: 15 July 2014
Ó Springer Science+Business Media New York 2014
Abstract A series of dihalosubstituted thiocarbamide
derivatives (5a–e, 6a–e, 7a–e, and 8a–e) were synthesized
as antitubercular agents. The structures of dihalosubstituted
thiocarbamide derivatives were established on the basis of
Keywords Antimycobacterial activity ꢀ
3-Chloro-4-fluoroaniline ꢀ 3,4-Dichloro aniline ꢀ
Thiocarbamide ꢀ Reductive amination
1
13
IR, H, C NMR, and mass spectral data. All the com-
pounds were tested in vitro for antimycobacterial activity
against Mycobacterium tuberculosis (ATCC-25177) by
well-diffusion method and MIC by serial dilution method.
Results of the antitubercular screening revealed that some
of the compounds showed moderate to good antitubercular
activity. Of all the compounds tested, two derivatives viz.,
Introduction
Tuberculosis (TB) is a highly prevalent infectious disease
and had been the major cause of mortality worldwide. The
World Health Organization (WHO) has estimated in 2011
that about 8.7 million people fell ill due to the infection of
Mycobacterium tuberculosis (Mtb), the causative agent of
TB and 1.4 million died from TB. It is the second most
deadly disease only next to HIV/AIDS, and among HIV-
infected people with weakened immune system, TB is a
leading killer of people causing one-quarter of all deaths
8
7
d and 8e expressed MIC of 25 lg/ml, and one compound
e showed MIC of 12.5 lg/ml against M. tuberculosis
(
ATCC-25177).
(WHO Fact Sheet, 2013). This situation has been further
exacerbated by increasing reports on drug-resistant M.
tuberculosis strains viz. the virtually incurable extensive
drug-resistant TB (XDR-TB) (Andrews et al., 2007 and
Jain and Mondal, 2008) and serious multidrug-resistant TB
M. Faiz Arshad (&) ꢀ A. H. Al Rohaimi ꢀ
A. A. Hassan ꢀ A. Elkerdasy
Department of Pharmaceutical Sciences, College of Pharmacy,
Shaqra University, Al-dawadmi, P.O. Box 33, Shagra,
Saudi Arabia
(MDR-TB), which are the cause of great concern, as they
e-mail: drfaizarshad@gmail.com
are resistant to both first-line and second-line TB drugs
S. Kumar
Department of Pharmaceutical Chemistry, Faculty of Pharmacy,
Jamia Hamdard, New Delhi 110062, India
(
Gandhi et al., 2006 and Donald and Van Helden, 2009).
Thioamide-containing drugs, Ethionamide (ETH) and
Prothionamide (PTH), have been broadly used to control
mycobacterial infections caused by Mycobacterium tuber-
culosis, M. leprae, and M. avium complex infections
A. A. Hassan
Department of Chemistry, Faculty of Science, Suez University,
Suez, Egypt
(
Fajardo et al., 2006 and Yajko et al., 1987). ETH and PTH
are both bactericidal, and they are the most frequently used
drugs for the treatment of drug-resistant TB and, therefore,
are becoming increasingly relevant as the number of mul-
tidrug-resistant and extensively drug-resistant cases
worldwide (CDC, 2006 and Crofton et al., 1997). More-
over, ETH and PTH are also used in a combined
A. Elkerdasy
Department of Biochemistry, College of Veterinary Medicine,
Sadat University, Sadat City, Egypt
N. Upmanyu
Department of Pharmaceutical Chemistry, R.K.D.F. College of
Pharmacy, Bhopal 462047, Madhya Pradesh, India
1
23

Med Chem Res (2015) 24:334–343
335
Fig. 1 Chemical structures of
various antitubercular drugs and
their mode of action showing
activator and final targets (Feng
et al., 2007). The sign ‘‘?’’
denotes unclear targets of drugs
like TAC, ISO and PZA. TAC
and ISO after activation through
EthA act on unknown targets
inhibiting mycolic acid
biosynthesis (InhA-independent
mechanisms). Similarly PncA
activated PZA acts on unknown
target resulting in the disruption
of membrane transport and
energetics
Drug
Activator
Targets
Effect
O
NH2
Disruption of
membrane
transport and
energetics
N
PZA
PncA
KatG
?
N
O
NHNH2
InhA
INH
N
S
NH2
ETH
N
H
N
NH2
O
N
?
EthA
S
N
TAC
H
?
O
O
S
Oleic
Acid
DesA3
N
N
H
H
ISO
chemotherapy regimen with either Dapsone or Rifampin to
specifically inhibited through inhibition of the stearoyl-
treat leprosy (Katoch et al., 1992).
CoA desaturase DesA3 by activated ISO (Dover et al.,
2007 and Feng et al., 2007).
Impelled by these observations and to progress the
Background
development of potent and effective newer antitubercular
agents, it was envisaged to synthesize newer thiocarbamide
derivatives with chemical modification of ETH and
exposing these newer thiocarbamides against M. tubercu-
losis (Mtb). The chemical modification strategy was opted
in the hope that it may provide information in the identi-
fication of some new targets or enzymes/receptors which
involve in biosynthesis of mycolic acid, since different
thiocarbamide drugs (ETH, TAC, ISO, and C26) act
through different final targets upon metabolic activation by
protein EthA.
Studies carried out in the field of TB biochemistry have
revealed that M. tuberculosis is unique among bacteria;
therefore, several drugs require for activation in situ to
produce inhibitory effect (Fraaije et al., 2004). Drugs such
as Isoniazid (INH), ETH, and Pyrazinamide (PZA) all
require metabolic activation for exerting lethal effects
against the deadly M. tuberculosis. These prodrugs get into
tubercle bacilli by passive diffusion, where they are acti-
vated by specific proteins to a range of reactive radicals or
species. PZA is activated by the nicotinamidase-peroxidase
PncA, whereas INH is activated by the catalase-peroxidase
KatG. These radicals then attack on multiple targets as
specific targets in the cell are shown in Fig. 1. Similarly,
several thiocarbamide groups containing drugs e.g., ETH,
TAC, ISO, C26, etc., require metabolic activation by pro-
tein EthA, following which the activated product exert its
lethal effect by interacting with a final target. Studies on
genetically modified and wild-type Mycobacterium bovis
BCG strain have shown that ETH, TAC, and ISO are all
activated by protein EthA in vivo, and each drug acts on
different final targets that ultimately lead to inhibition of
mycolic acid biosynthesis which result in bactericidal
effect of these drugs. Oleic acid synthesis appears to be
Results and discussion
Chemistry
The various secondary amines (3a–3e and 4a–4e) of
3-chloro-4-fluoroaniline or 3,4-dichloroaniline were syn-
thesized by direct reductive amination using NaBH in the
4
presence of iodine as reducing agent as outlined in
Scheme 1. The reaction was carried out by simply stirring
1.0 equivalent of aldehyde and 1.2 equivalents of aromatic
amine in methanol in the presence of the NaBH reagent.
4
The iodine catalyzed the in situ formation of an imine at
123

3
36
Med Chem Res (2015) 24:334–343
Scheme 1 Route of synthesis
of dihalosubstituted
thiocarbamide derivatives
R1
S
NH2
(
5a–e, 6a–e, 7a–e, and 8a–e).
Reagents and conditions:
a) NaBH /I , methanol, stirring
O
R
N
N
H
(
4 2
+
R
r.t. (b) phenylisothiocyanate,
ethanol, reflux
(c) methylisothiocyanate,
ethanol, reflux
R1
Cl
R2
a
Cl
(1, 2)
b
[
(7a-e) (8a-e)]
R1
R
2
R
NH
c
R1
S
Cl
R
N
N
H
R2
[
(3a-e) (4a-e)]
Cl
R2
[(5a-e) (6a-e)]
room temperature that was ultimately reduced in situ to the
3-chloro-4-fluoroaniline were observed as two doublets,
one at d value 6.48–6.50 (J = 8.0 Hz) for H-6 proton and
another at d value 7.16–7.18 (J = 7.8 Hz) for H-5 proton.
A singlet at d value 6.79 was identified for H-2 proton. The
secondary amine by NaBH (Bawa et al., 2011). The sec-
4
ondary amines of 3-chloro-4-fluoroaniline or 3,4-dichlo-
roaniline were served as penultimate intermediate for
synthesis of thiourea derivatives (5a–5e, 6a–6e, 7a–7e, and
1
3
C NMR spectrum of 5a compound was discussed as
1
3
8
a–8e). The thiocarbamide derivatives (5a–5e, 6a–6e, 7a–
e, and 8a–8e) were synthesized by reacting secondary
prototype to support the C NMR data of other compounds.
The signal due to C=S carbon was observed at d value
176.5, while the methine carbon was observed at d value
65.9. The fact was also supported by MS spectrum of
7
amines (3a–3e, 4a–4e) with methylisothiocyanate or
phenylisothiocyanate in absolute ethanol. The combustion
analysis of compounds (5a–5e, 6a–6e, 7a–7e, and 8a–8e)
was found to be within the acceptable limit of ± 0.4 %.
?
compound which exhibited molecular ions (M ) peak at m/z
260 and (M?2) peak at 262 for compound 5a. Similarly,
spectral characterization of compounds (7a–e and 8a–e) is
1
discussed by exemplifying 7a as prototype compound. In H
The structures of thiocarbamide derivatives (5a–5e, 6a–6e,
7
1
a–7e, and 8a–8e) were established on the basis of IR, H,
1
3
and C NMR and mass spectral data. In FTIR, the char-
acteristic C=S and NH bands were observed in the range of
NMR spectrum of compound 7a, the signal due to NH
proton of CSNHPh group was resonated as broad singlet at d
value 7.82 ppm which was found to be D O exchangeable,
1
340–1361 and 3309–3342, respectively, for compound
2
1
5a–5e, 6a–6e). In H NMR spectrum of compound 5a, the
(
while methine function of[CHNCSNHPh group was found
to be a multiplet of one proton resonating at d value
NH function of[NCSNH proton resonated as broad singlet
1
3
at d value 5.12 ppm which was D O exchangeable, while
2.76 ppm. In C NMR spectrum of the compound 7a, the
signal due to C=S carbon was observed at d value 177.4.
The methylene carbon rasonated at d value 65.5 while
methyl carbon of isopropyl group was observed at d value
20.2 and 20.9 respectively. Similarly, the FAB-MS
2
the methine proton was observed as multiplets at d value
2
.70 ppm. The signal due NHCH proton in spectrum of
3
compounds 5a appeared as broad singlet integrating for
three protons at d value 2.86 ppm. The aromatic protons of
1
23

Med Chem Res (2015) 24:334–343
337
spectrum of compound 7a was also recorded to further
support the structure of compound. The molecular ion peak
Table 1 Antimycobacterial activity screening data of dihalosubsti-
tuted thiocarbamide derivatives (5a–5e, 6a–6e, 7a–7e, and 8a–8e)
?
M ) was identified at m/z 322 and for M ? 2 at m/z 324.
(
Compd.
no.
R
R
1
R
2
Antitubercular activity
against ATCC
All these data suggest successful synthesis of target
compounds.
Preliminary
screening
MIC
Antimycobacterial activity
(ZOI in mm)
at 1,000 lg/ml
The antimycobacterial activity of compounds (5a–5e, 6a–
e, 7a–7e, and 8a–8e) was determined by drug-diffusion
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
8
8
8
8
8
a
b
c
CH
CH
3
3
CH
CH
3
3
F
F
F
F
F
9.93 ± 0.41
8.02 ± 0.35
11.08 ± 0.29
12.60 ± 0.38
13.84 ± 0.44
10.02 ± 0.37
09.59 ± 0.42
12.07 ± 0.32
14.82 ± 0.45
15.40 ± 0.44
10.06 ± 0.43
11.04 ± 0.38
11.15 ± 0.31
17.81 ± 0.42
19.85 ± 0.40
11.92 ± 0.48
10.51 ± 0.36
13.93 ± 0.44
18.88 ± 0.40
20.38 ± 0.37
–
[400
[400
400
400
200
[400
[400
400
200
100
[400
400
400
50
6
CH
2
technique in Lowenstein Jensen medium (LJM) against the
M. tuberculosis (ATCC-25177) as test organism (Gupta
et al., 2010). A stock solution of 10 mg/ml of sample was
prepared in DMSO which was further diluted to 1 mg/ml
for primary screening. MICs of test compounds were
determined by adding twofold serial dilutions of test
compounds in DMSO in conc. range of 6.25, 12.5, 25.0, 50,
Cyclohexyl
Furyl
d
e
H
Thienyl
CH
CH
CH
3
3
3
a
b
c
CH
CH
3
3
Cl
Cl
Cl
Cl
Cl
F
CH
2
Cyclohexyl
Furyl
d
e
H
1
00, 200, and 400 lg/ml in LJM and observing in which of
the tubes the microorganism did not show growth after
8 days at 37 °C. The results of antimycobacterial activity
Thienyl
CH
CH
CH
3
3
3
a
b
c
CH
CH
3
3
2
CH
2
F
are presented in Table 1. Figure 2 shows a bar diagram of
preliminary activity of test compounds at 1 mg/ml. Results
of preliminary antimycobacterial screening suggested that
among all the derivatives (5a–5e, 6a–6e, 7a–7e, and 8a–
Cyclohexyl
Furyl
F
d
e
H
F
Thienyl
CH
CH
CH
3
3
3
F
12.5
400
[400
400
25
a
b
c
CH
CH
3
3
Cl
Cl
Cl
Cl
Cl
8
e), compounds 5a, 5b, 6a, 6b, 7a, and 8b exhibited feeble
antimycobacterial activity (ZOI \ 10.51 mm) at conc. of
,000 lg/ml, while their MICs were found to be[400 lg/
ml. The thiocarbamide derivatives exhibited MIC at
00 lg/ml against bacterial strain viz. M. tuberculosis
ATCC-25177) includes 5c, 5d, 6c, 7c, 8a and 8c. Among
CH
2
Cyclohexyl
Furyl
1
d
e
H
Thienyl
CH
3
25
4
DMSO
INH
–
(
NT
3.12
3.12
the thiocarbamide (5a–5e, 6a–6e, 7a–7e, and 8a–8e)
derivatives, compound viz. 8d and 8e expressed good
activity against M. tuberculosis (ATCC-25177) and their
MICs were found to be 25 lg/ml. While thiocarbamide
derivatives 6e and 7d showed MIC of 100 and 50 lg/ml,
respectively, against test strain, only one compound i.e., 7e
exhibited MIC of 12.5 50 lg/ml against M. tuberculosis
ETH
NT
NT not tested, – inactive
found to be the highest among the series, their antimyco-
bacterial activity against M. tuberculosis (ATCC-25177)
was lower than the furan or thiophene derivatives. More-
over, it was also noticed the synthesized compounds which
exhibited moderate to good antimycobacterial activity
against the test strain M. tuberculosis (ATCC-25177), and
their MICs were higher than the reference compounds i.e.,
INH and ETH (MIC 3.12 lg/ml).
(
ATCC-25177). A preliminary SAR may be deduced on
synthesized thiocarbamide derivatives (5a–5e, 6a–6e, 7a–
e, and 8a–8e). The presence of thiocarbamide group in all
7
the compounds may be the fact that all the derivatives were
active at conc. of 1,000 lg/ml in preliminary screening.
Among the compounds of series (5a–5e, 6a–6e, 7a–7e, and
1
a–8e), the MIC further decreases when the N of thio-
8
Experimental
carbamide is replaced by five-member heterocyclic ring
viz. furan/thiophene in compounds 5d, 5e, 6d, and 6e. The
antimycobacterial activity further increase when the N2
substituents are replaced by phenyl ring in compounds 7d,
Chemistry
Melting points were determined by the open capillary
method with electrical melting point apparatus and are
uncorrected. IR spectra were recorded as KBr (pallet) on
7
e, 8d, and 8e. The replacement of 3-fluoro group with
-chloro in compounds (6a–6e and 8a–8e) marginally
3
1
increase antimycobacterial activity. This may be due to the
increased hydrophobicity of dichloro compounds.
Although the Clog P values of cyclohexyl derivatives were
Nicolet, Protege 460 FTIR spectrophotometer and H and
1
3
C NMR spectra recorded on Bruker DPX 300 MHz
spectrophotometer using DMSO-d or CDCl as an NMR
6
3
123

3
38
Med Chem Res (2015) 24:334–343
Fig. 2 Bar diagram showing
antimycobacterial activity of
test compounds against M.
tuberculosis (ATCC-25177)
25
Antimycobacterial activity of test compounds against M.
2
1
1
0
5
0
5
0
tuberculosis (ATCC-25177)
5a
5b 5c 5d 5e 6a 6b 6c 6d 6e 7a 7b 7c 7d 7e 8a 8b 8c 8d 8e
Test Compounds (5a-5e, 6a-6e, 7a-7e & 8a-8e)
solvent. TMS used as internal standard and chemical shifts
the data reported in parts per million (in ppm) where s, bs, d,
t, and m designated as singlet, broad singlet, doublet, triplet,
refluxed for 8–10 h. After completion of the reaction
checked by TLC, the content of the flask reduced to half and
left overnight. The crystalline mass obtained was filtered off,
washed with ether, dried, and recrystallized from ethanol.
The physicochemical and spectral data of synthesized com-
pounds (5a–e, 6a–e) are given below.
1
3
and multiplet, respectively. In case of C NMR spectrum,
0
0
C-1 -C6 represented the substituted aromatic ring carbons
0
0
00
whereas C1 –C6 represented the carbons of un-substituted
aromatic ring. Similarly, thiophene and furan carbons were
indicated with their respective names. Mass spectra were
recorded on JEOL SX102/DA-6000 mass spectrometer
using m-nitrobenzylalcohol as a matrix and elemental ana-
lysis on CHN Analyzer Perkin Elmer 2400. Thin Layer
Chromatography (TLC) was performed to monitor progress
of the reaction and purity of the compounds, spot being
located under iodine vapor or UV-light.
1-(3-Chloro-4-fluorophenyl)-1-isopropyl-3-methylthiourea
(5a)
Yield 56 %; Yellowish brown (EtOH); (The compound
was prepared by procedure mentioned above); mp
154–155 °C; Clog P 2.85; IR (KBr) mmax; 3309, 1589,
-
1 1
1352, 1032 cm ; H NMR (300 MHz, CDCl ): d 1.65 (m,
3
0
The route of synthesis of various thiocarbamides
derivatives is outlined as scheme-1. The penultimate
intermediates (3a–e and 4a–e) were synthesized by litera-
ture method (Bawa et al., 2011).
6H, CH(CH ) ), 7.16–7.18 (d, 1H, J = 7.8 Hz, H-5 ), 6.79
3
2
0
0
(s, 1H, H-2 ), 6.48–6.50 (d, 1H, J = 8.0 Hz, H-6 ), 5.12
(bs, 1H, NH, D O-exchangeble), 2.86 (s, 3H, NH-CH ),
3
2
1
3
2.70 (m, 1H, CH); C NMR (CDCl , 75 MHz) d: 176.5
3
0
0
(
C, C=S), 154.5 (C, C-4 ), 137.3 (C, C-1 ), 129.1 (CH,
0
0
0
0
General method for the synthesis of compounds (3a–e,
4
C-6 ), 126.2 (CH, C-2 ), 120.7 (C, C-3 ), 113.7 (CH, C-5 ),
65.9 (CH, CH CHCH ), 32.2 (CH , NHCH ), 20.4 (CH ,
a–e)
3
3
3
3
3
CH CHCH ), 19.8 (CH , CH CHCH ); FAB-MS m/z 260
3
3
3
3
3
?
To a mixture of appropriate aldehydes/ketones (a–
e) (1.0 mmol) and 3-chloro-4-fluoroaniline or 3,4-dichlo-
roaniline (1.0 mmol) in 50 ml of methanol, 50 mg iodine
was added with stirring at room temperature, and then
(M ), 262 (M?2); Anal. Calcd for C H ClFN S (calcd.
11 14 2
260.76) C, 50.67; H, 5.41; N, 10.74. Found: C, 50.82 H,
5.44; N, 10.77.
5
5 mg of sodium borohydride was added portionwise with
1-sec-Butyl-1-(3-chloro-4-fluorophenyl)-3-methylthiourea
stirring. The reaction mixture was stirred further for 5–6 h.
The precipitate was formed, which was filtered, washed
with water, dried, and recrystallized from ethanol to give
crystalline product.
(5b)
Yield 49 %; Yellowish white (EtOH); (The compound was
prepared by procedure mentioned above); mp 172 °C; Clog
P 3.00; IR (KBr) mmax : 3323, 1596, 1349, 1026 cm ; 1H
NMR (300 MHz, CDCl ): d 7.17–7.19 (d, 1H, H-5 ,
J = 8.0 Hz), 6.80 (s, 1H, H-2 ), 6.51–6.53 (d, 1H, H-6 ,
-
1
0
0
General method for the synthesis of compounds (5a–e,
6
3
0
a–e)
J = 7,8 Hz), 5.60 (bs, 1H, NH, D O-exchangeble), 2.86 (s,
2
To a solution of compound (3a–e) or (4a–e) (0.05 mol) in
absolute ethanol 30 mL, equimolar amount of methylisoth-
iocyanate was added, and the content of the flask was
3H, NH-CH ), 2.68 (m, 1H, CH), 1.39–1.68 (m, 5H,
3
1
CH CHCH ), 0.97 (t, 3H, CH ); C NMR (CDCl3,
3
2
3
3
0
0
75 MHz) d: 176.4 (C=S), 154.3 (C, C-4 ), 137.5 (C, C-1 ),
1
23

Med Chem Res (2015) 24:334–343
339
0
0
0
0
1
28.2 (CH, C-6 ), 125.9 (CH, C-2 ), 121.2 (C, C-3 ), 114.0
0
1H, H-6 , J = 7.3 Hz), 6.11–6.23 (m, 3H, thiophen-H),
(
CH, C-5 ), 66.8 (CH, CH CH CHCH ), 31.9 (CH ,
3
5.07 (bs, 1H, NH, D O-exchangeble), 4.02 (q, 1H, CH),
2
3
2
3
NHCH3), 26.5 (CH2, CH CH CHCH ), 15.8 (CH3,
3
2.78 (s, 3H, NH-CH3), 1.38–1.39 (d, 3H, CH3,
1
2
3
3
CH CH CHCH ), 12.5 (CH , CH CH ); Anal. Calcd for
2
J = 4.3 Hz); C NMR (CDCl , 75 MHz) d: 176.4 (C,
3
2
3
3
3
3
0
0
C H ClFN S (calcd. 274.79): C, 52.45; H, 5.87; N,
1
C=S), 154.7 (C, C-4 ), 136.9 (C, C-1 ), 129.8 (CH, C-3,
0
2
16
2
1
0.19. Found: C, 52.28; H, 5.88; N, 10.23.
thiophene), 129.3 (CH, C-4, thiophene), 128.6 (CH, C-6 ),
1
27.7 (C, C-2, thiophene), 127.0 (CH, C-5, thiophene),
0
0
0
1
-(3-Chloro-4-fluorophenyl)-1-cyclohexyl-3-
126.1 (CH, C-2 ), 122.2 (C, C-3 ), 113.8 (CH, C-5 ), 69.2
(CH, CH CH), 30.8 (CH , NHCH ), 20.3 (CH , CH CH);
methylthiourea (5c)
3
3
3
3
3
Anal. Calcd for C H ClFN S (calcd. 328.86): C, 51.13;
14
1
4
2 2
Yield 38 %; Light brown (MeOH); (The compound was
H, 4.29; N, 8.52. Found: C, 51.13; H, 4.29; N, 8.52.
prepared by procedure mentioned above); mp 140–142 °C;
-
1
Clog P 4.80; IR (KBr) mmax; 3342, 1582, 1350, 1039 cm
;
1-(3,4-Dichlorophenyl)-1-isopropyl-3-methylthiourea (6a)
0
0
NMR (300 MHz, CDCl ): d 7.17–7.19 (d, 1H, H-5 ,
3
0
J = 7.6 Hz), 6.80 (s, 1H, H-2 ), 6.49–6.51 (d, 1H, H-6 ,
Yield 60 %; Creamy white (EtOH) (The compound was
J = 7.2 Hz), 4.89 (bs, 1H, NH, D O-exchangeble), 2.86 (bs,
2
prepared by procedure mentioned above); mp 151–152 °C;
-
1 1
3
1
1
H, NH-CH ), 2.65 (m, 1H, CH), 1.47–1.69 (m, 4H, CH ),
3
Clog P 3.30; IR (KBr) mmax 3336, 1596, 1361, 1023 cm ; H
2
1
3
0
0
.19–1.40 (m, 6H, CH2); C NMR (CDCl , 75 MHz) d:
NMR (300 MHz, CDCl ): d 7.17–7.19 (d, 1H, H-5 ,
3
3
0
0
0
76.1 (C, C=S), 155.2 (C, C-4 ), 137.8 (C, C-1 ), 128.9 (CH,
0
J = 7.1 Hz), 6.74 (s, 1H, H-2 ), 6.55–6.57 (d, 1H, H-6 ,
0
0
0
C-6 ), 126.3(CH, C-2 ), 121.0 (C, C-3 ), 113.7 (CH, C-5 ),
2.4 (CH, cyclohexyl), 32.3 (CH , NHCH ), 30.9 (CH ,
J = 7.8 Hz), 5.10 (bs, 1H, NH, D O-exchangeble), 2.74 (m,
2
1
1H, CH), 1.69 (m, 6H, CH(CH3)2); C NMR (CDCl3,
3
7
3
3
2
0
0
cyclohexyl), 30.7 (CH , cyclohexyl), 25.7 (CH , cyclo-
2
75 MHz) d: 177.2 (C, C=S), 140.3 (C, C-1 ), 132.4 (C, C-3 ),
2
0
0
0
hexyl), 25.1 (CH , cyclohexyl), 24.4 (CH , cyclohexyl);
2
129.6 (C, C-4 ), 128.9 (CH, C-6 ), 128.4 (CH, C-5 ), 127.8
0
2
Anal. Calcd for C H ClFN S (calcd. 300.82): C, 55.90; H,
1
(CH, C-2 ), 66.3 (CH, CH CHCH ), 32.2 (CH , NHCH ),
3
4
18
2
3
3
3
6
.03; N, 9.31. Found: C, 55.68; H, 6.05; N, 9.35.
20.2 (CH , CH CHCH ), 19.8 (CH , CH CHCH ); Anal.
3 3 3 3 3 3
Calcd for C H Cl N S (calcd. 277.21): C, 47.66; H, 5.09;
14
1
1
2 2
1
-(3-Chloro-4-fluorophenyl)-1-(furan-2-ylmethyl)-3-
N, 10.11. Found: C, 47.18; H, 5.11; N, 10.15.
methylthiourea (5d)
1-sec-Butyl-1-(3,4-dichlorophenyl)-3-methylthiourea (6b)
Yield 54 %; Beige-colored solid (MeOH); (The compound
was prepared by procedure mentioned above); mp
Yield 55 %; Light Brown (EtOH); (The compound was
1
85–186 °C; Clog P 2.90; IR (KBr) m
3327, 1597, 1340,
prepared by procedure mentioned above); mp 143 °C; Clog
max
-
1
-1
1
028 cm ; NMR (300 MHz, CDCl ): d 7.68–7.70 (dd, 1H,
P 3.45; IR (KBr) mmax : 3327, 1599, 1358, 1029 cm ,
3
0
0
0
NMR (300 MHz, CDCl ): d 7.20–7.22 (d, 1H, H-5 ,
H-5 J = 7.1 Hz, J = 2.3 Hz), 7.20 (s, 1H, H 2 ), 6.81 (d,
0
3
0
0
1
H, H-6 , J = 7.3 Hz), 6.39–6.48 (m, 3H, Furan-H), 5.25
J = 7.2 Hz), 6.81 (s, 1H, H-2 ), 6.52–6.54 (d, 1H, H-6 ,
(
bs, 1H, NH, D O-exchangeble), 4.64 (q, 2H, CH ), 2.84 (s,
2
J = 6.9 Hz), 5.29 (bs, 1H, NH, D O-exchangeble), 2.89
2
2
1
3
3
H, NH-CH3); C NMR (CDCl , 75 MHz) d: 177.4 (C,
(bs, 3H, NH-CH ), 2.70 (m, 1H, CH), 1.37–1.64 (m, 5H,
3
3
0
13
CH CHCH ), 1.01 (t, 3H, CH ); C NMR (CDCl3,
C=S), 154.8 (C, C-4 ), 148.5 (C, C-2, furan), 142.1 (CH, C-5,
0
2
3
3
0
0
0
furan), 137.3 (C, C-1 ), 128.5 (CH, C-6 ), 126.2 (CH, C-2 ),
0
75 MHz) d: 176.5 (C, C=S), 139.8 (C, C-1 ), 131.9 (C,
0
0
0
0
0
1
21.0 (C, C-3 ), 113.7 (CH, C-5 ), 110.5 (CH, C-3, furan)
10.9 (CH, C-4, furan), 60.6 (CH , NCH ), 31.6 (CH
C-3 ), 130.0 (C, C-4 ), 129.7 (CH, C-6 ), 128.6 (CH, C-5 ),
0
1
128.2 (CH, C-2 ), 67.2 (CH, CHCH ), 31.7 (CH , NHCH ),
3
2
2
3
3
3
?
NHCH ); FAB-MS m/z 362 (M ), 364 (M?2). Anal. Calcd
27.4 (CH , CH CH ), 16.8 (CH , CHCH ), 11.7 (CH ,
2 2 3 3 3 3
3
?
for C H ClFN OS (calcd. 290.76): C, 52.26; H, 4.05; N,
2
CH CH ); FAB-MS; m/z 290 (M ), 292 (M?2), 294
2 3
1
2
13
9
.38. Found: C, 52.59; H, 4.08; N, 9.43.
(M?4). Anal. Calcd for C H Cl N S (calcd. 291.24): C,
12 16 2 2
49.49; H, 5.54; N, 9.62. Found: C, 49.76; H, 5.56; N, 9.67.
1
-(3-Chloro-4-fluorophenyl)-3-methyl-1-(1-(thiophen-2-
ylethyl)thiourea (5e)
1-Cyclohexyl-1-(3,4-dichlorophenyl)-3-methylthiourea
6c)
(
Yield 51 %; Yellowish Brown (EtOH); (The compound
was prepared by procedure mentioned above); mp
Yield 40 %; Yellowish white (EtOH); (The compound was
1
1
93–194 °C; Clog P 3.30; IR (KBr) m
3337, 1583, 1360,
0
0
prepared by procedure mentioned above); mp 160–162 °C;
max
-
1
-1
033 cm ; NMR (300 MHz, CDCl ): d 7.51 (dd, 1H, H-5
Clog P 5.25; IR (KBr) mmax 3338, 1590, 1361, 1030 cm ;
3
0
NMR (300 MHz, CDCl ): d 7.17–7.19 (d, 1H, H-5 ,
J = 7.3 Hz, J = 2.5 Hz), 7.17 (s, 1H, H-2 ), 6.43–6.45 (d,
3
123

3
40
Med Chem Res (2015) 24:334–343
0
0
J = 7.2 Hz), 6.80 (s, 1H, H-2 ), 6.49–6.51 (d, 1H, H-6 ,
General method for the synthesis of compound (7a–e,
8a–e)
J = 6.8 Hz), 5.06 (bs, 1H, NH, D O-exchangeble), 2.89
2
(
bs, 3H, NH-CH ), 1.44–1.65 (m, 4H, CH ), 1.17–1.41 (m,
3 2
1
3
6
1
H, CH2); C NMR (CDCl , 75 MHz) d: 176.8 (C, C=S),
To a solution of compound (3a–e) or (4a–e) (0.05 mol) in
absolute ethanol 30 mL, equimolar amount of phenyliso-
thiocyanate was added, and the content of the flask was
refluxed for 8–12 h. After completion of the reaction
checked by TLC, the content of the flask reduced to half
and left overnight. The crystalline mass obtained was fil-
tered off, washed with ether, dried, and recrystallized from
ethanol to give (7a–e, 8a–e). The physicochemical and
spectral data of compound (7a–e, 8a–e) are given below.
3
0
0
0
40.5 (C, C-1 ), 132.2 (C, C-3 ), 129.9 (C, C-4 ), 129.5
0
0
0
(
CH, C-6 ), 128.4 (CH, C-5 ), 127.9 (CH, C-2 ), 72.0 (CH,
cyclohexyl), 32.4 (CH , NHCH ), 31.6 (CH , cyclohexyl),
3
3
2
3
1.2 (CH , cyclohexyl), 25.9 (CH , cyclohexyl), 25.5
2 2
(
CH , cyclohexyl), 24.7 (CH , cyclohexyl); Anal. Calcd for
2 2
C H Cl N S (calcd. 317.28): C, 53.00; H, 5.72; N, 8.83.
1
4
18
2 2
Found: C, 52.79; H, 5.74; N, 8.89.
1
-(3,4-Dichlorophenyl)-1-(furan-2-ylmethyl)-3-
methylthiourea (6d)
1-(3-Chloro-4-fluorophenyl)-1-isopropyl-3-phenylthiourea
(
7a)
Yield 48 %; Brownish Yellow (EtOH); (The compound
was prepared by procedure mentioned above); mp
Yield 61 %; Cream-colored (EtOH); (The compound was
1
78–179 °C; Clog P 3.35; IR (KBr) m
3345, 1594, 1357,
max
prepared by procedure mentioned above); mp 160–161 °C;
-
1
1
036 cm ; NMR (300 MHz, CDCl ): d 7.73 (dd, 1H,
-1
3321, 1594, 1367, 1041 cm ;
3
Clog P 3.88; IR (KBr) m
max
0
0
H-6 , J = 7.8 Hz, J = 2.4 Hz) 7.18–7.20 (d, 1H, H-6 ,
0
1
H NMR (300 MHz, CDCl ): d 7.82 (bs, 1H, NH, D O-
3
2
J = 7.0 Hz), 6.80 (s, 1H, H-2 ), 6.41–6.49 (m, 3H, Furan-
0
exchangeble), 7.06–7.08 (d, 1H, H-5 , J = 7.8 Hz),
0
H), 5.30 (bs, 1H, NH, D O-exchangeble), 4.66 (s, 2H,
2
1
CH ), 2.80 (s, 3H, NH-CH ); C NMR (CDCl , 75 MHz)
6
.67–6.78 (m, 6H, Ar–H), 6.50 (s, 1H, H-2 ), 2.76 (m, 1H,
13
3
2
3
3
CH), 1.68 (m, 6H, CH(CH ) );
3
C NMR (CDCl3,
0
2
d: 177.8 (C, C=S), 149.3 (C, C-2, furan), 141.7 (CH, C-5,
furan), 139.7 (C, C-1 ), 132.3 (C, C-3 ), 130.1 (C, C-4 ),
7
5 MHz) d: 177.4 (C, C=S), 154.6 (C, C-4 ), 139.7 (C,
0
0
0
0
0
0
00
00
C-1 ), 136.7 (C, C-1 ), 129.6 (CH, C-3 , C-5 ), 128.6 (CH,
00
0
0
0
1
1
29.4 (CH, C-6 ), 128.7 (CH, C-5 ), 127.9 (CH, C-2 ),
10.7 (CH, C-3, furan), 110.9(CH, C-4, furan), 61.1 (CH2,
0
00
0
C-2 ), 127.8 (CH, C-4 ), 126.7 (CH, C-6 ), 125.8 (CH,
00
0
0
C-2 , C-6 ), 121.5 (C, C-3 ), 113.9 (CH, C-5 ), 65.5 (CH,
CH CHCH ), 20.9 (CH3, CH CHCH ), 20.2 (CH3,
NCH2), 32.2 (CH3, NHCH3); Anal. Calcd for
C H Cl N OS (calcd. 315.22): C, 49.53; H, 3.84; N,
3
3
3
3
1
3
12
2 2
?
CH CHCH ); FAB-MS; m/z 322 (M ), 324 (M?2); Anal.
3
3
8
.89. Found: C, 49.26; H, 3.85; N, 8.93.
Calcd for C H ClFN S (calcd. 322.83): C, 59.53; H,
2
1
6
16
5.00; N, 8.68. Found: C, 59.29; H, 5.02; N, 8.72.
1
-(3,4-Dichlorophenyl)-3-methyl-1-(1-(thiophen-2-
yl)ethyl)thiourea (6e)
1-sec-Butyl-1-(3-chloro-4-fluorophenyl)-3-phenylthiourea
Yield 53 %; Gray white solid (EtOH); (The compound was
(7b)
prepared by procedure mentioned above); mp 205 °C; Clog
-
1
P 3.75; IR (KBr) mmax 3329, 1593, 1355, 1032 cm ; NMR
Yield 57 %; Yellowish brown (MeOH); (The compound
was prepared by procedure mentioned above); mp
179–180 °C; Clog P 4.02; IR (KBr) mmax 3337, 1598, 1370,
0
300 MHz, CDCl ): d 7.53 (dd, 1H, H-5 , J = 7.8 Hz,
J = 2.1 Hz) 7.19 (s, 1H, H-2 ), 6.49–6.51 (d, 1H, H-6 ,
J = 8.2 Hz), 6.38–6.45 (m, 3H, thiophen-H), 5.04 (bs, 1H,
(
3
0
0
-
1
1037 cm ; NMR (300 MHz, CDCl
): d 7.56 (bs, 1H, NH,
O-exchangeble), 7.07–7.09 (d, 1H, H-5 , J = 7.8 Hz),
3
0
NH, D O-exchangeble), 4.06 (q, 1H, CH), 2.84 (s, 3H, NH-
2
D
2
1
CH ), 1.34–1.35 (d, 3H, CH , J = 4.1 Hz); C NMR
3
0
6.92 (s, 1H, H-2 ), 6.50–6.83 (m, 5H, Ar–H), 2.72 (m, 1H,
CH), 1.52–1.59 (m, 2H, CH ), 0.99–1.21 (m, 6H, CH );
, 75 MHz) d: 177.6 (C, C=S), 154.7 (C,
3
3
0
(
CDCl , 75 MHz) d: 176.9 (C, C=S), 139.8 (C, C-1 ), 132.5
2
3
3
1
3
0
0
(
C, C-3 ), 131.4 (C, C-4 ), 130.3 (CH, C-2, thiophene),
0
C NMR (CDCl
3
0
0
00
0
00
1
29.7 (CH, C-6 ), 129.2 (CH, C-5 ), 128.3 (CH, C-5, thi-
0
C-4 ), 139.3 (C, C-1 ), 137.2 (C, C-1 ), 129.2 (CH, C-3 ,
00 0 00
ophene), 127.9 (C, C-3, thiophene), 127.6 (CH, C-2 ),
C-5 ), 128.5 (CH, C-2 ), 127.9 (CH, C-4 ), 126.9 (CH,
0
0
00
00
1
26.6 (CH, C-4, thiophene), 70.2 (CH, CHCH ), 32.0
3
C-6 ), 126.2 (CH, C-2 , C-6 ), 121.3 (C, C-3 ), 114.1 (CH,
0
(
CH , NHCH ), 19.7 (CH , CHCH ); FAB-MS; m/z 344
3
C-5 ), 66.9 (CH, CH
3
CH), 26.8 (CH
CH), 13.0 (CH , CH CH ); Anal. Calcd for
18ClFN S (calcd. 336.85): C, 60.61; H, 5.39; N, 8.32.
Found: C, 60.37; H, 5.42; N, 8.36.
2 3 2
, CH CH ), 16.7
3
3
3
?
M ), 346 (M?2); Anal. Calcd for C H Cl N S (calcd.
(
(CH
3
, CH
3
3
3
2
1
4
14
2 2 2
3
4
45.31): C, 48.70; H, 4.09; N, 8.11. Found: C, 48.54; H,
.11 N, 8.15.
C
17
H
2
1
23

Med Chem Res (2015) 24:334–343
341
0
1
-(3-Chloro-4-fluorophenyl)-1-cyclohexyl-3-
128.7 (CH, C-5, thiophene), 128.3 (CH, C-2 ), 127.8 (C,
C-2, thiophene), 127.2 (CH, C-4, thiophene), 126.7 (CH,
phenylthiourea (7c)
0
00
00
0
C-6 ), 125.8 (CH, C-2 , C-6 ), 121.4 (C, C-3 ), 113.8 (CH,
0
Yield 43 %; Light brown solid (EtOH); (The compound
was prepared by procedure mentioned above); mp
C-5 ), 69.2 (CH, CH CH), 20.1 (CH , CH CH); Anal.
3
3
3
Calcd for C H ClFN S (calcd. 390.93): C, 58.38; H,
1
9
16
2 2
1
52–153 °C; Clog P 5.83; IR (KBr) m
3329, 1593, 1366,
4.13; N, 7.17. Found: C, 58.17; H, 4.16; N, 7.20.
max
-
1
1
032 cm ; NMR (300 MHz, CDCl ): d 7.82 (bs, 1H, NH,
3
0
D O-exchangeble) 7.19–7.21 (d, 1H, H-6 , J = 8.4 Hz),
2
1-(3,4-Dichlorophenyl)-1-isopropyl-3-phenylthiourea (8a)
0
7
.09–7.12 (d, 1H, H-5 , J = 8.0 Hz), 6.62-6.77 (m, 5H,
0
Ar–H), 6.52–6.54 (d, 1H, H-2 , J = 8.4 Hz), 2.59 (m, 1H,
Yield 64 %; Beige-colored (EtOH) (This compound was
CH), 1.43–1.68 (m, 4H, CH ), 1.16–1.41 (m, 6H, CH );
2
prepared by procedure mentioned above); mp 170 °C; Clog
P 4.33; IR (KBr) mmax 3323, 1597, 1363, 1037 cm ; H
2
1
3
-1 1
C NMR (CDCl , 75 MHz) d: 177.2 (C, C=S), 154.0 (C,
3
0
0
0
00
0
00
C-4 ), 138.8 (C, C-1 ), 137.0 (C, C-1 ), 129.7 (CH, C-3 ,
0
NMR (300 MHz, CDCl ): d 7.50 (bs, 1H, NH, D O-ex-
3
2
0
00
0
C-5 ), 128.7(CH, C-2 ), 128.1 (CH, C-4 ), 126.6 (CH,
00
changeble) 7.19–7.21 (d, 1H, H-5 , J = 8.2 Hz), 7.06–7.08
0
00
0
0
C-6 ), 126.2 (CH, C-2 , C-6 ), 121.6 (C, C-3 ), 113.6 (CH,
(d, 1H, H-6 , J = 7.6 Hz), 6.67 (s, 1H, H-2 ), 6.48-6.50 (m,
13
0
C-5 ), 72.6 (CH, cyclohexyl), 32.4 (CH , cyclohexyl), 32.3
2
5H, Ar–H),1.68 (m, 6H, CH(CH3)2); C NMR (CDCl3,
0
(
CH , cyclohexyl), 25.8 (2 9 CH , cyclohexyl) 25.5 (CH ,
2
75 MHz) d: 176.8 (C, C=S), 139.6 (C, C-1 ), 138.0 (C,
2
2
00 0 0 00
cyclohexyl); Anal. Calcd for C H ClFN S (calcd.
1
C-1 ), 132.3 (C, C-3 ), 129.6 (C, C-4 ), 129.2 (CH, C-3 ,
9
20
2
00 0 0
C-5 ), 128.9 (CH, C-6 ), 128.7 (CH, C-5 ), 127.6 (CH,
3
5
62.89): C, 62.88; H, 5.56; N, 7.72. Found: C, 62.63; H,
.58; N, 7.77.
0
0
00
00
C-4 ), 126.3 (CH, C-2 , C-6 ), 65.7 (CH, CH CHCH ),
3
3
20.1 (CH , CH CHCH ), 19.9 (CH , CH CHCH ); Anal.
3 3 3 3 3 3
1
-(3-Chloro-4-fluorophenyl)-1-(furan-2-ylmethyl)-3-
Calcd. for C H Cl N S (calcd. 339.28): C, 56.64; H,
16 16 2 2
phenylthiourea (7d)
4.75; N, 8.26. Found: C, 56.39; H, 4.78; N, 8.32.
Yield 48 %; Gray white (EtOH); (The compound was
1-sec-Butyl-1-(3,4-dichlorophenyl)-3-phenylthiourea (8b)
prepared by procedure mentioned above); mp 190–192 °C;
Clog P 3.93; IR (KBr) mmax 3329, 1593, 1366, 1032 cm
-
1
;
Yield 65 %; Brownish Yellow (EtOH); (The compound was
NMR (300 MHz, CDCl ): d 7.85 (bs, 1H, NH, D O-ex-
prepared by procedure mentioned above); mp 164 °C; Clog
P 4.47; IR (KBr) mmax 3332, 1588, 1352, 1028 cm ; NMR
3
2
-
1
changeble) 7.69–7.75 (m, 3H, Ar–H), 7.18–7.23 (m, 3H,
Ar–H), 6.79– 6.83 (m, 2H, Ar–H), 6.37–6.46 (m, 3H,
(300 MHz, CDCl ): d 7.63 (bs, 1H, NH-exchangeble)
3
1
Furan-H), 4.64 (s, 2H, CH2); C NMR (CDCl , 75 MHz)
3
0
0
3
7.20–7.22 (d, 1H, H-5 , J = 8.0 Hz), 7.04–7.07 (s, 1H, H-2 ),
0
0
d: 176.7 (C, C=S), 153.7 (C, C-4 ), 149.6 (C, C-2, furan),
6.67–6.81 (m, 5H, Ar–H), 6.54–6.56 (d, 1H, H-6 ,
0
0
0
1
41.8 (CH, C-5, furan), 138.8 (C, C-1 ), 137.0 (C, C-1 ),
00
J = 7.6 Hz), 2.75 (m, 1H, CH), 1.44–1.68 (m, 5H,
13
0
0
0
1
29.5 (CH, C-3 , C-5 ), 128.6 (CH, C-2 ), 127.7(CH,
0
CH CHCH ), 1.02 (t, 3H, CH ); C NMR (CDCl , 75 MHz)
2
3
3
3
0
0
00
00
0 00
C-4 ), 126.9 (CH, C-6 ), 126.7 (CH, C-2 , C-6 ), 120.8 (C,
0
d: 176.9 (C, C=S), 139.6 (C, C-1 ), 138.1 (C, C-1 ), 132.5 (C,
0
0 0 00 00
C-3 ), 129.9 (C, C-4 ), 129.5 (CH, C-3 , C-5 ), 128.9 (CH,
C-3 ), 114.2 (CH, C-5 ), 110.9 (CH, C-4, furan), 110.7 (CH,
C-3, furan), 62.0 (CH ); Anal. Calcd. for C H ClFN OS
0
0
00
00
2
18 14
2
C-6 ), 127.8 (CH, C-5 ), 127.4 (CH, C-4 ), 126.2 (CH, C-2 ,
00
C-6 ), 68.2 (CH, CH CH), 26.7 (CH , CH CH ), 16.7 (CH ,
3 2 3 2 3
(
calcd. 360.83): C, 59.91; H, 3.91; N, 7.76. Found: C,
6
0.08; H, 3.94; N, 7.79.
CHCH3), 12.7 (CH3, CH CH ); Anal. Calcd for
3 2
C H Cl N S (calcd. 353.31): C, 57.79; H, 5.14; N, 7.93.
1
7
18
2 2
1
-(3-Chloro-4-fluorophenyl)-3-phenyl-1-(1-(thiophen-2-
Found: C, 57.56; H, 5.16; N, 7.97.
yl)ethyl)thiourea (7e)
1-Cyclohexyl-1-(3,4-dichlorophenyl)-3-phenylthiourea
Yield 55 %; Beige-colored (EtOH); (The compound was
(8c)
prepared by procedure mentioned above); mp 207–209 °C;
Clog P 4.33; IR (KBr) mmax 3337, 1597, 1368, 1037 cm
-
1
;
Yield 36 %; Light Yellowish (MeOH); (The compound
was prepared by procedure mentioned above); mp
NMR (300 MHz, CDCl ): d 7.73 (bs, 1H, NH, D O-ex-
3
2
0
changeble) 7.51 (dd, 1H, H-5 J = 7.8 Hz, J = 2.7 Hz),
155–156 °C; Clog P 6.28; IR (KBr) m
3329, 1603, 1350,
max
0
0
-1
7
6
3
1
.47 (s, 1H, H-2 ), 7.17–7.19 (d, 1H, H-6 , J = 7.8 Hz),
1041 cm ; NMR (300 MHz, CDCl ): d 7.78 (bs, 1H, NH,
3
0
.41–6.65 (m, 5H, Ar–H), 4.06 (q, 1H, CH), 1.37-1.38 (d,
1
H, CH , J = 4.3 Hz); C NMR (CDCl , 75 MHz) d:
D O-exchangeble) 7.18–7.20 (d, 1H, H-5 , J = 8.4 Hz),
2
3
0
3
3
7.11-7.13 (s, 1H, H-2 ), 6.77-6.80 (m, 2H, Ar–H),
0
0
00
76.2 (C, C=S), 154.6 (C, C-4 ), 139.5 (C, C-1 ), 136.7 (C,
0
6.67–6.70 (m, 3H, Ar–H), 6.56–6.58 (d, 1H, H-6 ,
00
00
C-1 ), 129.6 (CH, C-3 , C-5 ), 129.2 (CH, C-3, thiophene),
J = 8.0 Hz), 2.62 (m, 1H, CH), 1.45-1.67 (m, 4H, CH2),
123

3
42
Med Chem Res (2015) 24:334–343
1
3
1
.12-1.40 (m, 6H, CH2); C NMR (CDCl , 75 MHz) d:
solution of 10 mg/ml of sample was prepared in DMSO
which was further diluted to 1 mg/ml for primary screen-
ing. After this, 50 ll of working solution was poured into
the wells, and plates were incubated for 12–15 days at
37 °C. Zone of inhibition was measured by digital vernier
caliper. MICs were determined by adding two serial dilu-
tions of test compounds in DMSO in conc. range of 6.25,
12.5, 25.0, 50, 100, 200, and 400 lg/ml in LJM and
observing in which of the tubes the microorganism did not
show growth after 28 days at 37 °C. Positive control was
done using inoculation in LJ media.
3
0
00
1
76.2 (C, C=S), 139.4 (C, C-1 ), 138.3 (C, C-1 ), 132.4 (C,
0
0
00
00
C-3 ), 129.7 (C, C-4 ), 129.2 (CH, C-3 , C-5 ), 128.8 (CH,
00
0
0
C-6 ), 127.9 (CH, C-5 ), 127.5 (CH, C-4 ), 126.6 (CH,
0
0
00
C-2 , C-6 ), 72.4 (CH, cyclohexyl), 32.4 (2XCH , cyclo-
2
hexyl), 26.1 (2XCH , cyclohexyl), 25.5 (CH , cyclohexyl);
2
2
Anal. Calcd for C H Cl N S (calcd. 389.35): C, 60.16;
20
19
2 2
H, 5.31; N, 7.38. Found: C, 60.34; H, 5.34; N, 7.42.
1
-(3,4-Dichlorophenyl)-1-(furan-2-ylmethyl)-3-
phenylthiourea (8d)
Yield 60 %; Light Yellow (EtOH); (The compound was
prepared by procedure mentioned above); mp 199–201 °C;
Conclusion
-
1
;
Clog P 4.38; IR (KBr) mmax 3336, 1603, 1354, 1031 cm
0
NMR (300 MHz, CDCl3): d 7.89 (dd, 1H, H-5 ,
In the present investigation, a series of thiocarbamide
derivatives containing 3-chloro-4-fluoro aniline or 3,4-
dichloroaniline system were synthesized based on the
diversity in mechanism of action of various thioamides-
containing drugs (ETH, ISO). All the compounds (5a–5e,
6a–6e, 7a–7e, and 8a–8e) were screened for antimyco-
bacterial activity by drug-diffusion technique in LJM
against the M. tuberculosis (ATCC-25177) as test organ-
ism. The results of antimycobacterial screening exhibit that
for antimycobacterial activity, the presence of furan/thio-
phene ring at N1 of thiocarbamide function enhances an-
timycobacterial activity over the aliphatic that is isopropyl
or sec-isobutyl or cyclohexyl group, while the replacement
of 3-fluoro group with 3-chloro in compounds (6a–6e and
8a–8e) marginally increase antimycobacterial activity. Of
all the derivatives compounds, 8d, 8e, and 7e expressed
MIC of 25 and 12.5 lg/ml against M. tuberculosis (ATCC-
25177). These thiocarbamide derivatives discovered in this
study may be further exploited to improve their MIC and
may provide valuable therapeutic intervention for the
treatment of TB.
0
J = 7.8 Hz, J = 2.5 Hz), 7.81–7.84 (m, 2H, H-2 & NH),
0
7
.68–7.70 (d, 1H, H-6 J = 7.4 Hz), 7.19–7.26 (m, 3H, Ar–
1
H), 6.77–6.83 (m, 2H, Ar–H), 4.67 (s, 2H, CH2); C NMR
3
(
CDCl , 75 MHz) d: 177.2 (C, C=S), 149.3 (C, C-2, furan),
3
0 00
1
1
1
1
42.3 (CH, C-5, furan), 139.4 (C, C-1 ), 138.3 (C, C-1 ),
0
0
00
00
0
32.4 (C, C-3 ), 130.0 (C, C-4 ), 129.7 (CH, C-3 , C-5 ),
0
0
28.6 (CH, C-6 ), 128.3 (CH, C-5 ), 127.2 (CH, C-4 ),
0
0
00
26.5 (CH, C-2 , C-6 ), 110.6 (CH, C-4, furan), 110.2
(
CH, C-3, furan), 61.2 (CH , NCH ); Anal. Calcd for
2 2
C H Cl N OS (calcd. 377.29): C, 57.30; H, 3.74; N,
1
8
14
2 2
7
.42. Found: C, 57.48; H, 3.75; N, 7.46.
1
-(3,4-Dichlorophenyl)-3-phenyl-1-(1-(thiophen-2-
yl)ethyl)thiourea (8e)
Yield 53 %; Light brown (EtOH); (The compound was prepared
by procedure mentioned above); mp 212–213 °C; Clog P 4.78;
IR (KBr) mmax; 3329, 1593, 1355, 1032 cm ; NMR (300 MHz,
CDCl ): d 7.66 (bs, 1H, NH), 7.54–7.56 (d, 1H, H-5
-1
0
3
0
J = 7.6 Hz), 7.20-7.22 (s, 1H, H-2 ), 6.97–6.01 (m, 3H, Ar–H),
0
6
.72–6.78(m, 2H, Ar–H), 6.54(dd, 1H, H-6 ,J = 8.0 & 2.3 Hz),
13
C
Acknowledgments The authors are thankful to IIT Delhi for
recording NMR spectra and PBRI, Bhopal, India for antitubercular
screening of test compounds.
4
.03 (q, 1H, CH,), 1.33-1.34 (d, 3H, CH , J = 4.7 Hz);
3
0
NMR (CDCl , 75 MHz) d: 177.1 (C, C=S), 139.7 (C, C-1 ),
1
3
00 0 0
38.5 (C, C-1 ), 132.2 (C, C-3 ), 130.0 (C, C-4 ), 130.0 (CH,
00
0
0
C-3 , C-5 ), 129.8 (CH, C-3, thiophene), 128.9 (CH, C-5, thi-
0
0
0
ophene), 128.8 (CH, C-6 ), 128.7 (CH, C-5 ), 128.0 (CH, C-2 ),
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00
1
27.7 (C, C-2, thiophene), 127.2 (CH, C-4 ), 126.8 (CH, C-4,
0
0
00
thiophene), 126.4 (CH, C-2 , C-6 ), 69.2 (CH, CH CH), 19.9
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3 3
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