Synthesis and anti-microbial activity evaluation of some new 1-benzoyl-isothiosemicarbazides

Article abstract of DOI:10.1016/j.farmac.2004.07.012

The synthesis of some aroylisothiosemicarbazides was accomplished and their biological activity against bacteria, fungi, and mycobacteria was investigated. Different synthetic pathways were followed according to the kind of substituents that were introduced on both the aroyl ring and the sulfur atom. Anti-bacterial activity was measured against Staphylococcus aureus, S. epidermidis, Streptococcus agalactiae and S. faecalis, Escherichia coli, and Salmonella typhi, while antifungal activity was evaluated against C. albicans. Two species, Mycobacterium tuberculosis H37RV and Mycobacterium avium ATCC19421, were employed to evaluate antimycobacterial activity.

Full text of DOI:10.1016/j.farmac.2004.07.012

IL FARMACO 59 (2004) 945–952
http://france.elsevier.com/direct/FARMAC/
Synthesis and anti-microbial activity evaluation
of some new 1-benzoyl-isothiosemicarbazides
A. Plumitallo a, M.C. Cardia a, S. Distinto a, A. DeLogu b, E. Maccioni a,*
a Dipartimento Farmaco Chimico Tecnologico, Via Ospedale, 72, 09124 Cagliari, Italy
b Dipartimento di Scienze Chirurgiche e Trapianti d’Organo, Via Palabanda, 14, 09123 Cagliari, Italy
Received 9 June 2004; accepted 27 July 2004
Available online 30 September 2004
Abstract
The synthesis of some aroylisothiosemicarbazides was accomplished and their biological activity against bacteria, fungi, and mycobacteria
was investigated. Different synthetic pathways were followed according to the kind of substituents that were introduced on both the aroyl ring
and the sulfur atom. Anti-bacterial activity was measured against Staphylococcus aureus, S. epidermidis, Streptococcus agalactiae and S.
faecalis, Escherichia coli, and Salmonella typhi, while antifungal activity was evaluated against C. albicans. Two species, Mycobacterium
tuberculosis H37RV and Mycobacterium avium ATCC19421, were employed to evaluate antimycobacterial activity.
© 2004 Elsevier SAS. All rights reserved.
Keywords: Aroylisothiosemicarbazides; Synthesis; Anti-microbial activity
1. Introduction
Thiosemicarbazones (A) and thiosemicarbazides (B,
Fig. 1) are an important class of molecules with a large
spectrum of biological properties. These compounds have
been studied as anti-tubercular [1–3], anti-bacterial [4–7],
anti-malarial [8], anti-leprosy [9], anti-parasitic [10], anti-
neoplastic [11–13], and anti-viral [14] agents.
Nevertheless, their derivatives, isothiosemicarbazones
(C) and isothiosemicarbazides (D), have not been studied
extensively from a biological point of view.
In a previous investigation on isothiosemicarbazone deri-
vatives an interesting activity against both fungi and bacteria
has been shown [15–19]. Moreover, the influence of structu-
ral changes, such as, the nature and length of the side chain
on the sulphur atom, the introduction of different groups on
the arylidene aromatic ring, the substitution of the arylidene
hydrogen atom with an alkyl group, the introduction of alkyl
groups on the terminal nitrogen atom (N4), and the replace-
ment of the aromatic ring with heterocyclic rings or cycloal-
Fig. 1
.
kanes, have been investigated. On the basis of the obtained
data some structure–activity relationships have been pointed
out.
Furthermore, the introduction of different substituents on
the sulphur atom, standing the previously observed structural
requirements, leads to significant changes in the biological
properties.
The longer the alkyl chain on the sulphur atom, the higher
the activity. However, when the number of carbon atoms is
greater than four, a decrease in the biological activity was
observed.
* Corresponding author.
E-mail address: maccione@unica.it (E. Maccioni).
0014-827X/$ - see front matter © 2004 Elsevier SAS. All rights reserved.
doi:10.1016/j.farmac.2004.07.012

946
A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
A further increase in the biological activity was observed
but while method c uses pyridine, method a uses sodium
hydrogen carbonate.
when the alkyl chain was replaced with benzyl groups. In
particular the highest activity was observed when chlorinated
benzyl groups were introduced.
On the basis of the previously reported SAR data, a preli-
minary study on benzoylisothiosemicarbazides D has been
carried out, in order to investigate their antibacterial and/or
antifungal activity.
According to method b the desired aroylthiosemicarbazi-
des are obtained by reaction of the hydrazides with potas-
sium thiocyanate. Method a was used successfully to synthe-
sise benzoylthiosemicarbazide 1, but it failed when electron
withdrawing groups were present in the aromatic ring. In fact
when 4-nitrobenzoylchloride was used to achieve 4-nitro-
benzoylthiosemicarbazide 6, with method a, a single product
was obtained with high yields. Based on analytical and spec-
tral data, the obtained product was compound 17a and not the
expected derivative 6.
2. Results and discussion
2.1. Chemistry
Isothiosemicarbazides 9–16 (Table 2) have been synthe-
sised by alkylation of the corresponding thiosemicarbazides
1–8 (Table 1).
While slightly modifying the usual methods, three diffe-
rent synthetic pathways shown in Scheme 1 have been fol-
lowed to optimise the yields of the starting products 1–8
[20–24].
Methods a and c are similar and consist of the direct
benzoylation of the thiosemicarbazides in a base medium,
A
similar behaviour was observed when 2,4-
dichlorobenzoylchloride was reacted, though with some dif-
Table 1
Compounds 1–8
Compound
1 [20]
2 [20]
3 [20]
4 [20]
5 [22]
6 [20]
7
R
m.p. (°C)
198
203
218–20
236 d
204
216
234
172
Crystallisation solvent
I.R., cm–1 (nujol)
Phenyl
Water
Ethanol
Ethanol
Ethoxyethanol
Ethanol
Ethanol
DMF/water
Ethanol
3540–3180,1655,1260
3455–3175,1680,1260
3460–3180,1680,1260
3390–3130, 1660, 1275, 1250,
3380–3150,1660,1290
3500–3140, 1680, 1520, 1340, 1260
3380–3170, 1650, 1235, 1120
3430–3130,1660,1270
4-Methylphenyl
4-Chlorophenyl
4-Methoxyphenyl
2,4-Dichlorophenyl
4-Nitrophenyl
3,4,5-Trimethoxyphenyl
4-Fluorophenyl
8 [23]
Scheme 1
.

A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
947
Table 2
Analytical data of synthesized compounds 9–16
Compound Formula
m.p. (°C)
Yield %
85
80
82
63
72
91
77
77
82
75
83
76
71
70
78
78
81
80
78
47
52
49
44
80
65
R
R′
Crystallisation solvent
Ethanol/charcoal
Ethanol/water
Ethanol/water
Methanol/water
Ethyl acetate
Ethyl acetate
Ethanol
9a
C9H11N3OS
231d
235d
227d
230d
244d
252d
248d
248d
241d
248d
244d
242d
210d
157-160
205
Phenyl
Methyl
9b
9c
9d
C
C
C
C
C
C
11H13N3OS
15H14N3OSCl
12H17N3OS
10H13N3OS
12H15N3OS
16H16N3OSCl
Phenyl
Allyl
Phenyl
3-Chlorobenzyl
Butyl
Phenyl
10a
10b
10c
11a
11b
11c
12a
12b
12c
13a
13b
13c
14a
14b
14c
15a
15b
15c
16a
16b
16c
4-methylphenyl
4-methylphenyl
4-methylphenyl
4-chlorophenyl
4-chlorophenyl
4-chlorophenyl
4-methoxyphenyl
4-methoxyphenyl
4-methoxyphenyl
2,4-dichlorophenyl
2,4-dichlorophenyl
2,4-dichlorophenyl
4-nitrophenyl
Methyl
Allyl
3-Chlorobenzyl
Methyl
C9H10N3OSCl
THF/Et.ac. 2:1
Ethanol/water
Ethanol/methanol/water
Methanol
C11H12N3OSCl
C15H13N3OSCl2
C10H13N3O2S
C12H15N3O2S
C16H16N3O2SCl
Allyl
3-Chlorobenzyl
Methyl
Allyl
Ethanol/methanol/water
Acetonitrile
3-Chlorobenzyl
Methyl
C9H9N3OSCl2
Ethanol
C
11H11N3OSCl2
15H12N3OSCl3
Allyl
Ethanol/water
Ethanol/THF
Ethanol
C
168-170
176d
238d
235d
223d
236d
175d
235d
230d
229d
3-Chlorobenzyl
Methyl
C9H10N4O3S
C11H12N4O3S
C15H13N4O3SCl
C12H17N3O4S
C14H19N3O4S
C18H20N3O4SCl
4-nitrophenyl
Allyl
Methanol
4-nitrophenyl
3-Chlorobenzyl
Methyl
Methanol
3,4,5-trimethoxyphenyl
3,4,5-trimethoxyphenyl
3,4,5-trimethoxyphenyl
4-fluorophenyl
4-fluorophenyl
4-fluorophenyl
Acetonitrile
Allyl
Acetonitrile
3-Chlorobenzyl
Methyl
Methanol/water
Ethyl acetate
Ethanol/water
Ethanol/water
C9H10N3OSF
C11H12N3OSF
Allyl
C15H13N3OSClF
3-Chlorobenzyl
ferences. In this case a mixture of two products was obtained,
which after purification were identified as compound 17b
and the desired 2,4-dichlorobenzoylthiosemicarbazide 5.
The formation of compounds 17a and 17b is likely to
be due to the weak capability of sodium hydrogen carbonate
to behave as a base in a heterogeneous medium. The resulting
acidity of the reaction medium could lead to the formation
of the intermediate compound 18, through the reaction of
the protonated acetone and aroylthiosemicarbazide. This
reaction is favoured by the high electrophilicity of the carbo-
nyl carbon atom, which is due to the presence of electron
withdrawing groups in the adjacent aromatic ring.
Aroylthiosemicarbazides 2,3,4,7 and 8 were mostly pre-
pared with good yields using method c, while 4-nitro- and
2,4-dichloro-benzoylthiosemicarbazides 5 and 6 were prepa-
red using method b.
All the obtained isothiosemicarbazides have been purified
by crystallisation from the appropriate solvent and characte-
rised by elemental analysis, IR, and 1H-NMR.
Isothiosemicarbazides 9–16 have been synthesised, with
good yields, by alkylation of thiosemicarbazides 1–8 according
Only in the case of the 2,4-dichlorobenzoyl derivatives
13a, 13b and 13c did H-NMR reveal the presence of a
1
to two different procedures [25], as depicted in Scheme 2
.
double set of signals, probably indicating the presence of two

948
A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
Scheme 2
.
geometric isomers on the N=C bond. Any attempt to purify
the two diastereoisomers in crystalline form was unsuccess-
ful.
AMX (300 MHz) using tetramethylsilane (TMS) as internal
standard and DMSO as solvent (chemical shifts in d values).
Electron ionisation (EI) mass spectra were obtained by a
Fisons QMD 1000 mass spectrometer (70 eV, 200 µA, ion
source temperature 200 °C). The samples were introduced
directly into the ion source. Elemental analyses were obtai-
ned on a Perkin–Elmer 240 B microanalyser.
2.2. Microbiology
All the synthesised aroylisothiosemicarbazides were tes-
ted against several microbial species to investigate the in-
fluence of structural modifications on their antibacterial, an-
timycobacterial, and antifungal activity.
3.2. Chemistry
The structures of all compounds were assigned on the
basis of IR, NMR, Mass spectra, and elemental analysis.
Analytical data of the synthesised compounds are in
agreement with the theoretical data.
In particular the antibacterial activity of compounds was
measured against four Gram-positive species (Staphylococ-
cus aureus, S. epidermidis, Streptococcus agalactiae, and S.
faecalis), and two Gram-negative species (Escherichia coli
and Salmonella typhi), while their antifungal activity was
evaluated against C. albicans.
3.3. Synthesis of the starting aroylthiosemicarbazides 1–8
The antimycobacterial activity was evaluated against two
mycobacterial species (Mycobacterium Tuberculosis
H37RV, Mycobacterium Avium ATCC19421). All the mi-
croorganisms were isolated from clinical specimens.
None of the tested compounds exhibit interesting antibac-
terial or antifungal activity. Only in the case of compounds
14b and 15a, was an activity against M. tuberculosis obser-
ved at 25 and 50 µg/ml, respectively.
3.3.1. General methods
(a) Finely pulverised thiosemicarbazide (0.11 mol) and Na-
HCO3 (9 g) were suspended in dry acetone (155 ml) at
–5 °C. The reaction mixture was kept at –5 °C and under
vigorous stirring the appropriate benzoyl chloride
(0.1 mol) was added dropwise. The mixture was stirred
for 4 h at 0 °C, allowed to warm up to room temperature,
and then filtered. The solvent was eliminated under va-
cuum, thus obtaining an oil, which was crystallised from
the appropriate solvent.
As a matter of fact the replacement of the benzylidene
group, previously studied [17], with the benzoyl group leads
to a dramatic decrease in antimicrobial activity.
(b) A mixture of benzoylhydrazide (0.1 mol) and potassium
thiocyanate (0.13 mol) was refluxed in water (150 ml)
and concentrated hydrochloric acid (85 ml) for 3 h. The
mixture was allowed to cool and the formed precipitate
was filtered off, washed with water several times, and
crystallised from ethanol.
3. Experimental
3.1. Materials and methods
Melting points are uncorrected and were determined on a
Reichert Kofler thermopan apparatus. Infrared (I.R.) spectra
were recorded on a Perkin–Elmer 1640 FT spectrometer
(c) Finely powdered thiosemicarbazide (0.1 mol) was sus-
pended in dry pyridine (100 ml). The reaction mixture
was cooled down to –5 °C, and the appropriate benzoyl-
chloride (0.1 mol) added dropwise, keeping temperature
1
(nujol, cm–1). H-NMR spectra were recorded on a Bruker

A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
949
accurately under 0 °C. The reaction was stirred overnight.
The crude precipitate was filtered off, washed several
times with water, and crystallised.
room temperature for a further 30–90 min. The crude
reaction was filtered and the solvent evaporated, obtai-
ning a solid, which was washed with water and crystal-
lised.
Compounds 1-(4-methylbenzoyl)thiosemicarbazide 2,
1-(4-chlorobenzoyl)thiosemicarbazide 3, 1-(4-methoxy-
benzoyl)thiosemicarbazide 4, 1-(3,4,5-trimethoxybenzoyl)-
thiosemicarbazide 7, and 1-(4-fluorobenzoyl)thiosemi-
carbazide 8 were prepared in good yields using method c.
According to these two procedures isothiosemicarbazides
9–16 were synthesised
3.4.1.1. 1-benzoyl-S-methylisothiosemicarbazide 9a. 1H-
NMR (DMSO-d6) d: 2.48 (s, 3H, CH3); 6.70 (s, 2H, NH2,
D-exch.); 7.55 (t, 1H, J = 6.8, aromatic proton); 7.59 (t, 1H,
J = 7.5, aromatic proton); 7.62 (t, 1H, J = 6.8, aromatic
proton); 7.94 (d, 2H, J = 6.8, aromatic protons); 10.11 (s, 1H,
CONH, D-exch.).
Compounds 1-(2,4-dichlorobenzoyl)thiosemicarbazide
5
and 1-(4-nitrobenzoyl)thiosemicarbazide 6 were prepared
using method b.
3.3.1.1. Synthesis of benzoxathiadiazepines 17a
and b. Using method a to react p-nitrobenzoylchloride and
thiosemicarbazide, a single product was obtained, which was
identified by elemental analysis and with spectroscopics
method, as compound 17a. M.p. 157°C (crystallised from
ethanol). I.R. (Nujol): 3440, 3290, 3180 (NH2), 1590 (C=N),
1510 (NO2), 1340 (NO2), cm–1. 1H-NMR (DMSO-d6): 2.15
(s, 6H, CH3); 6.70 (s, 2H, NH2, D-exch.); 7.90 (d, 2H, J = 8.8,
aromatic protons); 8.40 (d, 2H, J = 8.8, aromatic protons).
m/z: 280 (M+.), 265, 206, 150, 104.
3.4.1.2. 1-benzoyl-S-allyl-isothiosemicarbazide 9b. 1H-
NMR (DMSO-d6) d: 3.77 (d, 2H, J = 6.7, CH2S); 5.20 (d, 1H,
J = 9.7, CH2=); 5.41 (d, 1H, J = 17.0, CH2=); 6.05–6.11 (m,
1H, –CH=); 6.72 (s, 1H, NH2, D-exch.); 7.54 (t, 1H, J = 6.8,
aromatic proton); 7.6 (t, 1H, J = 7.4, aromatic proton); 7.63
(t, 1H, J = 7.6, aromatic proton); 7.94 (d, 2H, J = 6.8,
aromatic protons); 10.11 (s, 1H, CONH, D-exch.).
When method a was used to achieve 1-(2,4-dichloro-
benzoyl)thiosemicarbazide, a mixture of two products was
obtained. These two products were separated by crystallisa-
tion from acetone and identified as 2,4-dichloroben-
zoylthiosemicarbazide 5 and 2,2-dimethyl-4-amino-7-(2,4-
dichlorophenyl)-2H-1,3,5,6-oxathiadiazepine 17b, which
was recrystallised from acetone, m.p. 178°C.
3.4.1.3. 1-benzoyl-S-(3-chlorobenzyl)isothiosemicarbazide
9c. 1H-NMR (DMSO-d6) d: 4.36 (s, 2H, SCH2); 6.78 (s, 2H,
NH2, D-exch.); 7.24 (t, 1H, J = 6.6, aromatic proton); 7.29 (d,
1H, J = 7.7, aromatic proton); 7.54 (t, 1H, J = 6.8, aromatic
proton); 7.6 (t, 1H, J = 7.4, aromatic proton); 7.61 (d, 1H,
J = 6.7, aromatic proton); 7.65 (t, 1H, J = 7.6, aromatic
proton); 7.71 (s, 1H, aromatic proton); 7.96 (d, 2H, J = 6.8,
aromatic protons); 10.26 (s, 1H, CONH, D-exch.).
I.R. (Nujol): 3380, 3230, 3145 (NH2), 1600 (C=N), 1515
(Ar), cm–1.
3.4.1.4. 1-benzoyl-S-butyl-isothiosemicarbazide 9d. 1H-
NMR (DMSO-d6) d: 1.01 (t, 3H, CH3); 1.50 (m, 2H,
CH2CH3); 1.73 (m, 2H, CH2CH2S); 3.08 (t, 2H, SCH2); 6.65
(s, 1H, NH2, D-exch.); 7.53 (t, 1H, J = 6.8, aromatic proton);
7.56 (t, 1H, J = 7.4, aromatic protons); 7.59 (t, 1H, J = 6.8,
aromatic proton); 7.92 (d, 2H, J = 7.4, aromatic protons);
10.07 (s, 1H, CONH, D-exch.).
1H-NMR (DMSO-d6): 2.16 (s, 6H, CH3), 6.63 (s, 2H,
NH2, D-exch.), 7.35 (d, 1H, J = 6.9, aromatic proton); 7.68
(d, 1H, J = 6.9, aromatic proton); 7.78 (s, 1H, aromatic
proton); m/z: 304 (M+.), 269, 230, 174, 146, 130.
3.4. Synthesis of Aroylisothiosemicarbazides 9–16
3.4.1. General methods
3.4.1.5. 1-(4-methylbenzoyl)-S-methyl-isothiosemicarbazide
10a. 1H-NMR (DMSO-d6) d: 2.47 (s, 6H, SCH3 andArCH3);
6.64 (s, 2H, NH2, D-exch.); 7.34 (d, 2H, J = 7.9, aromatic
protons); 7.83 (d, 2H, J = 7.7, aromatic protons); 9.99 (s, 1H,
CONH, D-exch.).
(A)1-aroylthiosemicarbazide (25 mmol) and the appropriate
alkyl halides (25 mmol) were refluxed in ethanol (80 ml)
for 1 h. The solution was allowed to cool down to room
temperature and then ethyl ether was added, thus obtai-
ning the precipitation of isothiosemicarbazide chloride.
The obtained solid was treated with a solution of
dimethylsulphoxide/water = 1:1 and the obtained solu-
tion was treated with NaHCO3 up to the alkaline reaction.
The formed isothiosemicarbazide was filtered, washed
several times with water, and crystallised from ethanol or
a mixture of ethanol/water. We generally perform this
reaction to prepare the allylic and benzylic derivative.
(B)Small portions of aroylthiosemicarbazide (30 mmol)
were added to an equimolecular solution of sodium hy-
droxide in ethanol (70 ml). The reaction mixture was
stirred for 30 min at room temperature and then alkyl
halides (30 mmol) were added. The mixture was stirred at
3.4.1.6. 1-(4-methylbenzoyl)-S-allyl-isothiosemicarbazide
10b. 1H-NMR (DMSO-d6) d: 2.47 (s, 3H, CH3); 3.77 (d, 2H,
J = 6.7, CH2S); 5.21 (d, 1H, J = 9.7, CH2=); 5.41 (d, 1H,
J = 17.0, CH2=); 6.05–6.10 (m, 1H, –CH=); 6.70 (s, 2H,
NH2, D-exch.); 7.36 (d, 2H, J = 7.5, aromatic protons); 7.85
(d, 2H, J = 7.7, aromatic protons); 10.03 (s, 1H, CONH,
D-exch.).
3.4.1.7. 1-(4-methylbenzoyl)-S-(3-chlorobenzyl)isothiosemi-
1
carbazide 10c. H-NMR (DMSO-d6) d: 2.47 (s, 3H, CH3);
4.36 (s, 2H, CH2); 6.75 (s, 2H, NH2, D-exch.); 7.24 (t, 1H,

950
A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
J = 6.6, aromatic proton); 7.29 (d, 1H, J = 7.7, aromatic
proton); 7.39 (d, 2H, J = 7.5, aromatic protons); 7.61 (d, 1H,
J = 6.7, aromatic proton); 7.74 (s, 1H, aromatic proton); 7.87
(d, 2H, J = 7.4, aromatic protons); 10.07 (s, 1H, CONH,
D-exch.).
CH2=); 6.01–6.14 (m, 1H, –CH=); 6.58 (s, 2H, NH2,
D-exch.); 7.46 (d, 1H, J = 6.8, aromatic proton); 7.63 (d, 1H,
J = 6.8, aromatic proton); 7.86 (s, 1H, aromatic proton);
10.17 (s, 1H, CONH, D-exch.).
3.4.1.16. 1-(2,4-dichlorobenzoyl)-S-(3-chlorobenzyl)isothio-
1
3.4.1.8. 1-(4-chlorobenzoyl)-S-methyl-isothiosemicarbazide
11a. 1H-NMR (DMSO-d6) d: 2.47 (s, 3H, CH3); 6.73 (s, 2H,
NH2, D-exch.); 7.62 (d, 2H, J = 8.4, aromatic protons); 7.97
(d, 2H, J = 8.4, aromatic protons); 10.17 (s, 1H, CONH,
D-exch.).
semicarbazide 13c. H-NMR (DMSO-d6) d: 4.36 (s, 2H,
SCH2); 6.69 (s, 2H, NH2, D-exch.); 7.24 (t, 1H, J = 6.6,
aromatic proton); 7.29 (d, 1H, J = 7.7, aromatic proton); 7.46
(d, 1H, J = 6.9, aromatic protons); 7.61 (d, 1H, J = 6.7,
aromatic proton); 7.64 (d, 1H, J = 6.8, aromatic proton); 7.73
(s, 1H, aromatic proton); 7.86 (s, 1H, aromatic proton); 10.26
(s, 1H, CONH, D-exch.).
3.4.1.9. 1-(4-chlorobenzoyl)-S-allyl-isothiosemicarbazide
1
11b. H-NMR (DMSO-d6) d: 3.76 (d, 2H, J = 6.7, CH2S);
5.19 (d, 1H, J = 9.9, CH2=); 5.38 (d, 1H, J = 17, CH2=);
6.05–6.14 (m, 1H, –CH=); 6.79 (s, 2H, NH2, D-exch.); 7.63
(d, 2H, J = 8.6, aromatic protons); 7.98 (d, 2H, J = 8.4,
aromatic protons); 10.19 (s, 1H, CONH, D-exch.).
3.4.1.17. 1-(4-nitrobenzoyl)-S-methyl-isothiosemicarbazide
14a. H-NMR (DMSO-d6) d: 2.48 (s, 3H, SCH3); 6.82 (s,
2H, NH2, D-exch.); 8.19 (d, 2H, J = 8.1, aromatic protons);
8.40 (d, 2H, J = 8.1, aromatic protons); 10.39 (s, 1H, CONH,
D-exch.).
1
3.4.1.10. 1-(4-chlorobenzoyl)-S-(3-chlorobenzyl)isothiosemi-
carbazide 11c. 1H-NMR (DMSO-d6) d: 4.36 (s, 2H, SCH2);
6.83 (s, 2H, NH2, D-exch.); 7.25 (t, 1H, J = 6.7, aromatic
proton); 7.29 (d, 1H, J = 7.7, aromatic proton); 7.63 (d, 1H,
J =7.4, aromatic protons); 7.73 (s, 1H, aromatic proton), 7.87
(d, 2H, J = 8.6, aromatic protons); 7.98 (d, 2H, J = 8.4,
aromatic protons); 10.23 (s, 1H, CONH, D-exch.).
3.4.1.18. 1-(4-nitrobenzoyl)-S-allyl-isothiosemicarbazide
14b. H-NMR (DMSO-d6) d: 3.78 (d, 2H, J = 6.5, CH2S);
5.21 (d, 1H, J = 10.4, CH2=); 5.41 (d, 1H, J = 16.9, CH2=);
5.93–6.14 (m, 1H, –CH=); 6.86 (s, 2H, NH2, D-exch.); 8.18
(d, 2H, J = 7.3, aromatic protons); 8.39 (d, 2H, J = 6.9,
aromatic protons); 10.42 (s, 1H, CONH, D-exch.).
1
3.4.1.11. 1-(4-methoxybenzoyl)-S-methyl-isothiosemicarba-
zide 12a. 1H-NMR (DMSO-d6) d: 2.47 (s, 3H, SCH3); 3.91
(s, 3H, OCH3); 6.66 (s, 2H, NH2, D-exch.); 7.08 (d, 2H,
J = 8.8, aromatic protons); 7.90 (d, 2H, J = 8.4, aromatic
protons); 9.97 (s, 1H, CONH, D-exch.).
3.4.1.19. 1-(4-nitrobenzoyl)-S-(3-chlorobenzyl)isothiosemi-
carbazide 14c. 1H-NMR (DMSO-d6) d: 4.39 (s, 2H, SCH2);
7.28 (s, 2H, NH2, D-exch.); 7.40 (t, 1H, J = 7.3, aromatic
proton); 7.47 (d, 1H, J = 8.1, aromatic proton); 7.59 (d, 1H,
J = 7.9, aromatic proton); 7.73 (s, 1H, aromatic proton); 8.21
(d, 2H, J = 8.4, aromatic protons); 8.40 (d, 2H, J = 8.4,
aromatic protons); 10.52 (s, 1H, CONH, D-exch.).
3.4.1.12. 1-(4-methoxybenzoyl)-S-allyl-isothiosemicarba-
1
zide 12b. H-NMR (DMSO-d6) d: 3.75 (d, 2H, J = 6.5,
CH2S); 3.91 (s, 3H, OCH3); 5.18 (d, 1H, J = 10.0, CH2=);
5.40 (d, 1H, J = 16.9, CH2=); 6.04-6.13 (m, 1H, –CH=); 6.67
(s, 2H, NH2, D-exch.); 7.07 (d, 2H, J = 8.8, aromatic pro-
tons); 7.92 (d, 2H, J = 8.8, aromatic protons); 9.97 (s, 1H,
CONH, D-exch.).
3.4.1.20. 1-(3,4,5-trimethoxybenzoyl)-S-methyl-isothiosemi-
carbazide 15a. 1H-NMR (DMSO-d6) d: 2.47 (s, 3H, SCH3);
3.81 (s, 3H, OCH3); 3.94 (s, 6H, OCH3); 6.67 (s, 2H, NH2,
D-exch.); 7.26 (s, 2H, aromatic protons); 10.03 (s, 1H,
CONH, D-exch.).
3.4.1.13. 1-(4-methoxybenzoyl)-S-(3-chlorobenzyl)isothio-
semicarbazide 12c. H-NMR (DMSO-d6) d: 3.93 (s, 3H,
3.4.1.21. 1-(3,4,5-trimethoxybenzoyl)-S-allyl-isothiosemi-
carbazide 15b. 1H-NMR (DMSO-d6) d: 3.76 (d, 2H, J = 6.9,
CH2S); 3.81 (s, 3H, OCH3); 3.94 (s, 6H, OCH3); 5.21 (d, 1H,
J = 10.1, CH2=); 5.41 (d, 1H, J = 17.0, CH2=); 6.06–6.11 (m,
1H, –CH=); 6.71 (s, 2H, NH2, D-exch.); 7.28 (s, 2H, aroma-
tic protons); 10.06 (s, 1H, CONH, D-exch.).
1
OCH3); 4.34 (s, 2H, SCH2); 6.71 (s, 2H, NH2, D-exch.); 7.12
(d, 2H, J = 8.1, aromatic protons); 7.24 (t, 1H, J = 6.6,
aromatic proton); 7.29 (d, 1H, J = 7.7, aromatic proton); 7.60
(d, 1H, J = 6.7, aromatic proton); 7.73 (s, 1H, aromatic
proton); 7.99 (d, 2H, J = 7.9, aromatic protons); 10.00 (s, 1H,
CONH, D-exch.).
3.4.1.22. 1-(3,4,5-trimethoxybenzoyl)-S-(3-chlorobenzyl)-
1
isothiosemicarbazide 15c. H-NMR (DMSO-d6) d: 3.82 (s,
3.4.1.14. 1-(2,4-dichlorobenzoyl)-S-methyl-isothiosemicar-
bazide 13a. H-NMR (DMSO-d6) d: 2.47 (s, 3H, SCH3);
6.61 (s, 2H, NH2, D-exch.); 7.57 (d, 1H, J = 6.7, aromatic
proton); 7.68 (d, 1H, J = 6.7, aromatic proton); 7.87 (s, 1H,
aromatic proton); 10.16 (s, 1H, CONH, D-exch.).
3H, OCH3); 3.95 (s, 6H, OCH3); 4.53 (s, 2H, CH2S); 7.17 (s,
2H, NH2, D-exch.); 7.33 (s, 2H, aromatic protons); 7.40 (t,
1H, J = 7.4, aromatic proton); 7.47 (d, 1H, J = 8.1, aromatic
proton); 7.59 (d, 1H, J = 7.4, aromatic proton); 7.70 (s, 1H,
aromatic proton); 10.55 (s, 1H, CONH, D-exch.).
1
3.4.1.15. 1-(2,4-dichlorobenzoyl)-S-allyl-isothiosemicarba-
zide 13b. H-NMR (DMSO-d6) d: 3.76 (d, 2H, J = 6.9,
CH2S); 5.21 (d, 1H, J = 10.1, CH2=); 5.41 (d, 1H, J = 17,
3.4.1.23. 1-(4-fluorobenzoyl)-S-methyl-isothiosemicarba-
zide 16a. 1H-NMR (DMSO-d6) d: 2.47 (s, 3H, SCH3); 6.72
(s, 2H, NH2, D-exch.); 7.36 (t, 2H, J = 8.8, aromatic protons);
1

A. Plumitallo et al. / IL FARMACO 59 (2004) 945–952
951
8.00 (dt, 2H, Jo = 8.8, Jm = 5.7, aromatic protons); 10.13 (s,
1H, CONH, D-exch.).
growers) or of 7 days (for fast growers) in a CO2 (5%
CO2–95% humidified air) incubator at 37 °C, organism
growth was scored. The MIC was defined as the minimum
concentration causing complete growth inhibition of orga-
nisms or allowing no more than five colonies to grow.
3.4.1.24. 1-(4-fluorobenzoyl)-S-allyl-isothiosemicarbazide
1
16b. H-NMR (DMSO-d6) d: 3.66 (d, 2H, J = 6.8, CH2S);
5.09 (d, 1H, J = 10.1, CH2=); 5.29 (d, 1H, J = 17.0, CH2=);
5.93–5.99 (m, 1H, –CH=); 6.64 (s, 2H, NH2, D-exch.); 7.25
(t, 2H, J = 8.8, aromatic protons); 7.88 (dt, 2H, Jo = 8.8,
Jm = 5.8, aromatic protons); 10.02 (s, 1H, CONH, D-exch.)
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