Heterocycles 23: Synthesis, characterization and anticancer activity of new hydrazinoselenazole derivatives

Article abstract of DOI:10.1007/s00044-013-0558-8

A series of novel functionalized 1,3-selenazole was synthesized by Hantzsch-type condensation reaction and evaluated for their in vitro cytotoxic activity against two human cancer cell lines. The structures of the synthesized selenosemicarbazones and func

Full text of DOI:10.1007/s00044-013-0558-8

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-013-0558-8
ORIGINAL RESEARCH
Heterocycles 23: Synthesis, characterization and anticancer
activity of new hydrazinoselenazole derivatives
•
•
•
•
´ ´
Valentin Zaharia Adriana Ignat Bathelemy Ngameni Victor Kuete
•
•
Marlyse L. Moungang Charles N. Fokunang Mihai Vasilescu
•
•
•
•
Nicolae Palibroda Castelia Cristea Luminita Silaghi-Dumitrescu
Bonaventure T. Ngadjui
Received: 2 January 2013 / Accepted: 20 February 2013
Ó Springer Science+Business Media New York 2013
Abstract A series of novel functionalized 1,3-selenazole
was synthesized by Hantzsch-type condensation reaction
and evaluated for their in vitro cytotoxic activity against
two human cancer cell lines. The structures of the syn-
thesized selenosemicarbazones and functionalized 2-hy-
drazinyl-1,3-selenazole derivatives were assigned based on
IR and NMR spectroscopic investigations, mass spec-
trometry, and elemental analysis data. Some of the syn-
thesized compounds showed significant cytotoxic
activities, the IC50 values below or around 10 lM were
recorded with compounds 1d and 4b on both androgen-
insensitive prostate cancer cells (DU-145) and hepatocar-
cinoma (Hep-G2) cell lines.
Introduction
Selenium used to be considered as an essential nutrient,
constituent of selenoproteins involved in self-defense
mechanism against oxidative stress (Wessjohann et al.,
2007; Naithani, 2008; Lopez et al., 2009), in reducing
certain inflammatory processes and in detoxification pro-
cesses (Akbaraly et al., 2005), but on the other hand,
selenium-accumulating plants grown in seleniferous soil
(Pire et al., 2007) were identified as causing livestock
poisoning. Based on the benefits associated to the presence
of selenium, the synthesis of many organoselenium deriv-
atives characterized by a large variety of biological activ-
ities was developed. The synthesis of heterocyclic systems
is of potential importance in the field of medicinal chem-
istry because most of the compounds with biological
properties are derived from heterocyclic structures.
Keywords Selenazole Á Hantzsch reaction Á
Cytotoxicity Á Prostate cancer Á Hepatocarcinoma
B. Ngameni (&) Á C. N. Fokunang Á B. T. Ngadjui
V. Zaharia (&) Á A. Ignat (&) Á B. Ngameni
Faculty of Medicine and Biomedical Sciences, University
Faculty of Pharmacy, ‘‘Iuliu Hatieganu’’ University of Medicine
and Pharmacy, Victor Babes 41, 400012 Cluj-Napoca, Romania
e-mail: vzaharia@umfcluj.ro
´
of Yaounde I, Yaounde, Cameroon
e-mail: bath_ngameni@yahoo.fr
´
A. Ignat
e-mail: adriana.ignat@umfcluj.ro
V. Kuete
Faculty of Science, University of Dschang, Dschang, Cameroon
M. Vasilescu
Faculty of Physics, ‘‘Babes¸ Bolyai’’ University,
M. Kogalniceanu 1, 400028 Cluj-Napoca, Romania
M. L. Moungang Á B. T. Ngadjui
´ ´
Faculty of Science, University of Yaounde I, Yaounde,
Cameroon
N. Palibroda
National Institute for Research and Development
of Isotopic and Molecular Technologies,
Donath 65-103, Cluj-Napoca 400028, Romania
A. Ignat Á C. Cristea Á L. Silaghi-Dumitrescu
Faculty of Chemistry and Chemical Engineering,
‘‘Babes Bolyai’’ University, Arany Janos 11,
400028 Cluj-Napoca, Romania
123

Med Chem Res
Similarly, heterocyclic compounds containing selenium
have received a great deal of attention due to the wide
variety of pharmacological activities reported for these
compounds, including anticancer (Srivastava and Robins,
1983), antibacterial (Goldstein et al., 1990), and antiviral
(Nguyen et al., 2009) properties. A number of recent
studies have indicated that 1,3-selenazole derivatives
inhibit the synthesis of nitric acid (Ueda et al., 2005) and
they are antagonists for histamine H2 receptors (van der
Goot et al., 1994). In addition, it has also been shown that
2-dialkyl-amino-1,3-selenazole derivatives described by
Kantlehner et al., 1996 were used as intermediates in the
synthesis of some dyes (Keil and Hartmann, 2000). N-acyl-
derivatives of 2-amino-4-(isothiocyanatomethyl)-1,3-sele-
nazole have been reported to possess antitumor activity
(Kumar et al., 1993). Recently, Nam et al., 2008 reported
the inhibitory activity of 2-piperidin- and 4-phenyl-2-
piperidin-1,3-selenazole upon anion-superoxidase. The lit-
erature survey regarding the biological effects of selenaz-
ole derivatives, the similarity between the chemical
properties of selenium and sulfur equally balanced by our
experience regarding the chemical synthesis and evaluation
of antimicrobial and antitumoral effects of hydrazino-thi-
azole derivatives (Renson, 1956; Boik, 2001), encouraged
us to synthesize a new series of hydrazino-1,3-selenazole
derivatives and to investigate their biological properties.
The 1,3-selenazole derivatives described below
(Schemes 1, 2, 3, 4) were obtained by Hantzsch-type
cyclization reaction between selenosemicarbazide precur-
sors (selenosemicarbazones or aroyl-selenosemicarbazide
derivatives respectively) and a-halogeno-carbonyl deriva-
tives. The anticancer effects of selenazoles in prostate DU-
145 and liver cancers have not been widely studied.
Despite recent advances in our understanding of the bio-
logical processes leading to the development of cancer,
there is still a need for new and effective agents to help
bringing this disease under control. Prompted by the fore-
going observations, coupled with our interest in the syn-
thesis of heterocyclic compounds, we have reported below
the synthesis of new hydrazinoselenazole derivatives and
the results of our investigations regarding their cytotoxic
activities.
Results and discussion
Chemical synthesis
The synthesis of the new selenazoles described in this work
used two precursors. The first precursors are the seleno-
semicarbozones 1a–c, obtained by the condensation of
selenosemicarbazide with (hetero) aromatic carbaldehydes
(Scheme 1).
The second precursors are the aroyl-selenosemicarbazide
derivatives 4a–b, are prepared by acylation of selenosemicar-
bazide (Scheme 3). The Hantzsch-type condensation between
the selenosemicarbazide derivatives with a-halogenocarbonyl
derivatives resulted to a new aryliden-hydrazinoselenazoles
2a–h (Scheme 2) and aroyl-hydrazinoselenazoles 5a–d
(Scheme 4).
For the synthesis of selenosemicarbazones 1a–d, a series
of aromatic carbaldehydes, such as benzaldehyde, p-chloro-,
and p-methoxy-benzaldehyde, as well as a heteroaromatic
carbaldehyde (2-phenyl-thiazole-4-carbaldehyde), was used
(Scheme 1). The new thiazolyl-selenosemicarbazone 1d
was obtained in satisfactory yields (55 %) by a procedure
previously applied for the preparation of 1a–c (Renson,
1956).
The selenosemicarbazones 1a–d were further subjected to
condensation using different a-halogenocarbonyl derivatives
such as monochloroacetone, 1,3-dichloroacetone, a-bro-
moacetophenone, 3-chloro-acetylacetone, and a-bromoace-
tylacetic ester, in DMF/acetone solution. A series of new
hydrazinoselenazoles 2a–h were thus obtained in satisfac-
tory yields (51–59 %) after 24-h reaction time at room
1
temperature. The H-NMR data indicate highly deshielded
protons in the NH groups characterized by chemical shifts
range 9.9–11.8 ppm for both semicarbazones 1a–d and
selenazoles 2a–h. Acetylation of the selenazoles 2a–h was
readily accomplished using acetic anhydride in the presence
of pyridine (Scheme 2), being obtained 3a–h compounds,
with yields between 46 and 68 %. The IR spectra of the
stable crystalline acetyl derivatives 3a–h display the typical
absorption bands.
The aroyl-selenosemicarbazides 4a–b were obtained in
good yields (58 and 65 %, respectively) by the reaction of
Scheme 1 Synthetic route to
selenosemicarbazones 1a–d
Ar-CH=N-NH-C-NH2
Ar-CH=O + H2N-NH-C-NH2
Se
1a-d
Se
1a
1b
1c
1d
C6H5-
pCl-C6H4-
pCH3O-C6H4-
C6H5-Th
Ar
N
C6H5
S
123

Med Chem Res
NH2
Se
CO R1
CH R2
Ar CH
N
NH
C
+
X
DMF, 24h
r.t
N
R1
R2
Ar CH
N
NH
Se
2a - h
Ac2O
Py, reflux
N
R1
R2
Ar CH
N
N
Se
CO
CH3
3a - h
2a, 3a
2b, 3b
2c, 3c
2d,3d
2e,3e
2f,3f
2g,3g
2h,3h
C6H4Cl(p)
CH3
H
C6H4Cl(p)
CH2Cl
H
C6H4Cl(p)
C6H5
C6H4Cl(p)
CH3
COOC2H5
C6H4OCH3(p)
C6H4OCH3(p)
C6H5-Th
CH2Cl
H
C6H5-Th
CH3
COCH3
Ar
R1
R2
CH3
H
C6H5
H
H
Scheme 2 Hantzsch type condensation to hydrazinoselenazoles and their acetylation
NaOH
During the acetylation of 5a–d with acetic anhydride, a
double acylation of the hydrazine group occured, leading to
diacetyl derivatives 6a–d (Scheme 4) in satisfactory yields.
The selenohydrazone 1d, the hydrazino-selenazoles 2a–
h, aroyl-selenosemicarbazide 4a–b aroyl-hydrazino-sele-
nazoles 5a–d, and their acyl derivatives (3a–h, 6a–d) were
reported here for the first time as obtained via total syn-
thesis based on the described protocols. The structures of
the synthesized compounds were fully assigned based on
Ar-CO-NH-NH-C-NH2
Ar-COCl + H2N-NH-C-NH2
r.t., 1h
Se
4a-b
Se
4a
C6H5
4b
C6H5Cl (p)
Ar
Scheme 3 Synthesis of aroyl-selenosemicarbazides
CO
R1
NH2
Se
+
Ar CO NH NH
C
CH R2
X
1
spectroscopic data (IR, H-, and 13C-NMR), mass spec-
trometry, and elemental analysis (cf. ‘‘Experimental.
Chemistry’’ section).
N
R1
R2
Ar CO NH NH
Se
5a-d
Biology
Ac2O
The synthetized compounds were tested for their cytotox-
icity against two human cancer cell lines and the results are
summarized in Table 1. In the US NCI plant screening
program, a sample is generally considered to have in vitro
cytotoxic activity if the IC50 value following incubation
between 48 and 72 h is less than 4 lg/ml for pure com-
pounds (Boik, 2001). This cutoff point for good cytotoxic
compound has also been defined as 10 lM (Brahemi et al.,
2010). In the present work, some of the synthesized com-
pounds showed significant cytotoxic activities, the IC50
values below or around 10 lM were recorded with com-
pounds 1d and 4b on both androgen-insensitive prostate
cancer cells (DU-145) and hepatocarcinoma (Hep-G2) cell
lines. Compounds 1b also exhibited significant cytotoxicity
against DU-145. The activity of the most active compound,
1c (IC50: 6.14 and 9.18 lM respectively against DU-145
and Hep-G2) can be considered as important with regard to
CH3 CO
N
R1
R2
Ar CO
N N
Se
CH3 CO
6a-d
5a,6a
C6H5
CH3
H
5b,6b
C6H5
C6H5
H
5c,6c
C6H5Cl (p)
5d,6d
C6H5Cl (p)
Ar
R1
R2
CH3
H
C6H5
H
Scheme 4 Hantzsch type condensation to aroyl-hydrazino-selena-
zoles 5a–d and their acetylation
acid chlorides (benzoylchloride and p-chlorobenzoylchlo-
ride, respectively) with selenosemicarbazide (Scheme 3).
Aroyl-hydrazino-selenazoles 5a–d were successfully
obtained by the condensation of 4a–b with monochloroacetone
and a-bromoacetophenone, respectively, in the presence of
aqueous NaOH (Scheme 4).
123

Med Chem Res
First, it appears that the presence of selenium is important for
cytotoxic activity. However, it was found that when selenium
atom is free in the structure, the activity was better than when
it was included in an heterocycle. For example, only but all
compounds of the series 1 (1a–d) and 4 (4a and 4b) exhibited
IC50 below 10 lg/ml. These compounds were generally the
most active samples. Second, within the compounds of series
1 and 4, those containing a chloride atom in position 4 of the
benzene cycle 1b (IC50: 8.63 and 12.97 lM on DU-145 and
Hep-G2, respectively) and 4b (IC50: 7.59 and 10.66 lM on
DU-145 and Hep-G2, respectively) were among the most
active. Finally, the presence of thiazolic and chloride sub-
stituents simultaneously in the structure of the compounds
seemed to improve their activities as observed with com-
pounds 2g (IC50: 16.37 and 18.76 lM on DU-145 and
Hep-G2, respectively) and 3g (IC50: 19.61 and 19.28 lM on
DU-145 and Hep-G2, respectively).
Table 1 Activity of the studied compounds and doxorubicin on
DU-145 and HepG-2 cancer cell lines
Compounds Cell lines and IC50 values in lg/ml and in lM
(in bracket)
DU-145
Hep-G2
1a
1b
1c
1d
2a
2b
2c
2d
2e
2f
9.22
2.25
7.76
1.9
(40.77)
(8.63)
8.84
3.38
(39.09)
(12.97)
(11.32)
(9.18)
(30.29)
(6.14)
2.9
2.84
14.74
[25
19.54
17.68
[25
18.15
6.25
19.42
20.63
24.28
[25
[25
[25
[25
8.31
13.51
8.5
(49.36)
([75.06)
(54.17)
(47.69)
([84.97)
(50.94)
(16.37)
(49.88)
(60.56)
(64.73)
([62.07)
([60.57)
([74.35)
([62.76)
(19.61)
(31.32)
(35.11)
(7.59)
16.86
[25
15.33
19.56
24.49
17.98
7.16
(56.46)
([75.06)
(42.50)
(52.77)
(83.24)
(50.47)
(18.76)
(61.31)
(59.24)
([66.65)
([62.07)
(55.15)
([74.35)
([62.76)
(19.28)
(29.35)
(34.82)
(10.66)
([89.23)
([73.05)
([79.46)
(62.89)
([68.63)
([58.64)
([62.70)
([54.26)
(4.89)
2g
2h
3a
3b
3c
3d
3e
3f
23.87
20.18
[25
[25
22.76
[25
[25
8.17
Conclusions
In conclusion, new hydrazinoselenazole derivatives were
synthesized and their structure were determined and also
assayed for their in vitro cytotoxic activity against two
human cancer cell lines. This synthesis offers significant
improvements over existing procedures and thus helps to
facilitate the entry into a synthesis of a variety of sele-
nazole compounds of potentially high synthetic and bio-
logical utilities. Also, this technique affords through one-
pot reaction a various selenazoles derivatives with excel-
lent yields and without formation of undesirable side
products. The studies on the hydrazinoselenazoles and their
derivatives as anticancer compounds are currently under
investigation in our laboratory.
3g
3h
4a
4b
5a
5b
5c
5d
6a
6b
6c
6d
12.66
8.43
2.22
[25
[25
[25
24.51
[25
[25
[25
[25
3.12
([89.23)
([73.05)
([79.46)
(65.07)
([68.63)
([58.64)
([62.70)
([54.26)
(3.27)
[25
[25
[25
23.69
[25
[25
[25
[25
2.66
Doxorubicin 1.78
Bold values indicate best activities
Experimental
Chemistry
Melting points were determined using an Electro thermal
IA 9200 digital melting point apparatus and are uncor-
rected. Elemental analyses were performed using a Vario
EL III instrument. The mass spectra were run on a Varian
MAT-311A instrument and using a Bruker Esquire 3000
ESI-ion trap-mass spectrometer. IR spectra were recorded
on a Bruker Vector 22 FT-IR spectrometer fitted with a
Golden Gate ATR accessory. NMR spectra were recorded
on a WM-400 MHz and 300 MHz Bruker NMR instrument
using CDCl3 or DMSO-d6 as solvent and TMS as internal
reference (chemical shifts in d, ppm).
that of the reference anticancer drug, doxorubicin (IC50:
3.27 and 4.89 lM, respectively, against DU-145 and Hep-
G2), as the compound was less than twofold less active.
This compound can therefore be considered as potential
cytotoxic drug and deserves further investigations on nor-
mals and other cancer cell lines as well as additional
pharmacological studies, and complementary assays on
normal cell lines.
When exploring the structure–activity relationship of the
studied compounds, three main points can be highlighted.
123

Med Chem Res
General procedure for the synthesis of aryliden-
selenosemicarbazides (1a–d)
2-Phenyl-1,3-thiazolo-5-methyliden-selenosemicarbazide
(1d) White crystals, yield = 55 %, m.p. = 189–190 °C, IR
(cm-1): 3359, 3265 (mNH); 3139 (mCH); 1620 (mC=N); 1529
(mC=Caromatic). MS (m/z): 308/310/312 (M?); 229; 189; 161;
2 mmol (0.27 g) selenosemicarbazide was dissolved in
5 ml glacial acetic acid and 2 ml ethanol. 2 mmol of aro-
matic carbaldehyde dissolved in 5 ml ethanol was added
and the reaction mixture was refluxed for 4 h. The hot
reaction mixture was filtered, the solution was cooled, and
the precipitate thus obtained was collected by filtration.
The purification of the product was performed by recrys-
tallization from DMF/acetic acid mixture in volumetric
ratio 1:2.
1
121(100 %); 104; 83; 77; 71; 57; 43. H-NMR (400 MHz,
DMSO-d6, d ppm): 7.49 (t, 2H,C6H5-meta, J = 8.6 Hz), 7.55
(t, 1H, C6H5-para, J = 8.6 Hz), 7.94 (d, 2H, C6H5-ortho,
J = 8.6 Hz), 8.29 (s, 1H, Th–CH), 8.37 (s, 1H, CH=N), 11.84
(s, 1H, NH), 13.02 (s, 2H, NH2). 13C-NMR (100.5 MHz,
DMSO-d6, d ppm): 120.1, 126.3, 126.5, 128.7, 129.4, 129.5,
136.1, 143.1, 152.4, 159.2, 164.3. Anal. Calcd. for: C11H10
N4SSe: C, 42.72 %; H, 3.26 %; N, 18.12 %; S, 10.37 %.
Found: C, 42.63 %; H, 3.20 %; N, 18.10 %; S, 10.30 %.
Benzyliden-selenosemicarbazide (1a) Yellow crystals,
yield = 63 %, m.p. = 169–170 °C [m.p. = 167–168 °C lit.
(Renson, 1956)], IR(cm-1): 3372, 3263 (mNH); 3024, 2921
(mCH); 1643 (mC=N); 1600 (mC=Caromatic). MS (m/z):
229/227/225 (M?); 145; 119; 103; 104, 77(100 %); 51; 43;
28. 1H-NMR (400 MHz, CDCl3, d ppm): 7.45 (t, 1H, C6H5-
para, J = 7.3 Hz), 7.54 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.77
(d, 2H, C6H5-ortho, J = 7.3 Hz), 7.85 (s, 1H, CH=N), 9.87
(s, 1H, NH), 10.16 (s, 2H, NH2). 13C-NMR (100.5 MHz,
CDCl3, d ppm): 126.1, 126.4, 128.1, 129.4, 129.7, 135.7,
143.7, 163.2. Anal. Calcd. for C8H9N3Se: C, 24.49 %; H,
4.01 %; N, 18.58 %. Found: C, 41.89 %; H, 4.03 %; N,
18.50 %.
General procedure for the preparation of aryliden-
hydrazino-selenazole (2a–h)
2 mmol selenosemicarbazone was dissolved in 5 ml DMF
and 5 ml anhydrous acetone. 2 mmol of a-halogenocar-
bonyl derivative was added. The reaction mixture was
stirred at room temperature for 24 h and then neutralized
with NaHCO3. The precipitate thus obtained was filtered
and then recrystallized from ethanol.
4-Methyl-2-[(4-chloro-benzyliden)-hydrazinyl]-1,3-selenazole
(2a) Pink crystals, yield = 52 %, m.p. = 193–195 °C, IR
(cm-1): 3179 (mNH); 2977, 2862 (mCH); 1630 (mC=N); 1575
(mC=Caromatic). MS (m/z): 297/299/301 (M?); 218; 188;
162(100 %); 160; 138; 120; 119; 111; 89; 75; 39; 1H-NMR
(300 MHz, CDCl3, d ppm): 2.41 (s, 3H, CH3), 7.15 (s, 1H,
CH–Se), 7.63 (d, 2H, C6H4-meta, J = 8.7 Hz), 7.89 (d, 2H,
C6H4-ortho, J = 8.7 Hz), 8.02 (s, 1H, CH=N), 10.12 (s, 1H,
NH). 13C-NMR (75.5 MHz, CDCl3, d ppm): 17.5, 116.2,
127.2, 127.6, 128.3, 128.7, 133.0, 137.1, 139.8, 151.9, 173.5.
Anal. Calcd. for C11H10N3ClSe: C, 44.24 %; H, 3.38 %; N,
14.07 %. Found: C, 44.02 %; H, 3.33 %; N, 14.05 %.
p-Chloro-benzyliden-selenosemicarbazide (1b) Yellow
crystals, yield = 61.23 %, m.p. = 220–221 °C [m.p. =
219–220 °C lit. (Renson, 1956)], IR(cm-1): 3417, 3265
(mNH); 3154, 2981 (mCH); 1602 (mC=N); 1560, 1525
(mC=Caromatic). MS (m/z): 263/261/259 (M?); 220; 179; 153;
1
140; 138(100 %); 111; 89; 77; 75; 28. H-NMR (400 MHz,
CDCl3, d ppm): 7.39 (d, 2H, C6H5-meta, J = 8.5 Hz), 7.77
(d, 2H, C6H5-ortho, J = 8.5 Hz), 7.88 (s, 1H, CH=N), 9.92
(s, 1H, NH), 10.18 (s, 2H, NH2). 13C-NMR (100.5 MHz,
CDCl3, d ppm): 127.7, 128.0, 128.9, 129.4, 130.4, 135.7, 145.7,
167.2. Anal. Calcd. for C8H8ClN3Se: C, 36.87 %; H, 3.09 %;
N, 16.13 %. Found: C, 36.45 %; H, 3.10 %; N,16.05 %.
4-Chloromethyl-2-[(4-chloro-benzyliden)-hydrazinyl]-1,3-
selenazole (2b) White crystals, yield = 51 %, m.p. =
210–211 °C, IR (cm-1): 3147 (mNH); 2960, 2862, 2786
(mCH); 1597 (mC=N); 1575 (mC=Caromatic). MS (m/z):331/
333/335 (M?); 298; 222; 196(100 %); 161; 138; 111; 89;
p-Methoxy-benzyliden-selenosemicarbazide (1c) White
crystals, yield = 62 %, m.p. = 183–184 °C [m.p. = 183–
184 °C lit. (Renson, 1956)], IR (cm-1): 3363, 3259 (mNH);
3123, 2973, (mCH); 1605 (mC=N); 1511 (mC=Caromatic). MS
(m/z): 255/257/259 (M?); 175; 140; 134(100 %); 108; 92;
77; 64; 39. 1H-NMR (400 MHz, CDCl3, d ppm): 3.82
(s, 3H, OCH3), 7.02 (d, 2H, C6H5-meta, J = 8.6 Hz), 7.68
(d, 2H, C6H5-ortho, J = 8.6 Hz), 7.76 (s, 1H, CH=N), 9.95
(s, 1H, NH), 10.16 (s, 2H, NH2). 13C-NMR (100.5 MHz,
CDCl3, d ppm): 55.4, 113.9, 114.0, 127.9, 128.4, 128.9,
146.1, 161.6, 167.2. Anal. Calcd. for C9H11N3OSe:
C, 24.20 %; H, 4.33 %; N, 16.40 %. Found: C, 23.99 %;
H, 4.20 %; N, 16.35 %.
1
75; 50; 39; 36; 28. H-NMR (300 MHz, CDCl3, d ppm):
4.68 (s, 2H, CH2Cl), 7.72 (s, 1H, CH–Se), 7.45 (d, 2H,
C6H4-meta, J = 8.7 Hz), 7.58 (d, 2H, C6H4-ortho,
J = 8.7 Hz), 8.12 (s, 1H, CH=N) 10.16 (s, 1H, NH). 13C-
NMR (75.5 MHz, CDCl3, d ppm): 40.3, 118.2, 127.3,
127.6, 128.3, 128.7, 133.0, 137.1, 139.7, 151.1, 170.6.
Anal. Calcd. for C11H9N3Cl2Se: C, 39.67 %; H, 2.72 %; N,
12.62 %. Found: C, 39.55 %; H, 2.69 %; N, 12.39 %.
4-Phenyl-2-[(4-chloro-benzyliden)-hydrazinyl]-1,3-selenazole
(2c) White crystals, yield = 56 %, m.p. = 184–185 °C,
123

Med Chem Res
IR (cm-1): 3140 (mNH); 3063, 2949 (mCH); 1595 (mC=N);
1570 (mC=Caromatic). MS (m/z): 359/363/361(M?); 359; 224;
182(100 %); 138; 111; 102; 89; 77; 51; 39; 28. H-NMR
J = 7.3 Hz), 7.65 (s, 1H, CH–Se), 8.01 (s, 1H, CH=N), 12.11
(s, 1H, NH). 13C-NMR (100.5 MHz, DMSO-d6, d ppm): 55.7,
114.4, 114.9, 115.3, 125.8, 126.6, 127.4, 127.9, 128.2, 128.5,
129.0, 129.1, 129.7, 160.8, 169.2, 171.5. Anal. Calcd. For
C17H15N3OSe C, 57.31 %; H, 4.24 %; N, 11.79 %. Found: C,
57.29 %; H, 4.18 %; N, 11.46 %.
1
(300 MHz, CDCl3, d ppm): 7.35 (t, 1H, C6H5-para,
J = 7.3 Hz), 7.48 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.56
(d, 2H, C6H5-ortho, J = 7.3 Hz), 7.43 (d, 2H, C6H4-meta,
J = 8.4 Hz), 7.91 (d, 2H, C6H5-ortho, J = 8.4 Hz), 7.85
(s, 1H, CH–Se), 8.08 (s, 1H, CH=N), 10.14 (s, 1H, NH).
13C-NMR (75.5 MHz, CDCl3, d ppm): 113.6, 126.1, 126.2,
127.2, 127.3, 128.3, 128.5, 128.7, 128.8, 129.4, 133.0, 135.0,
137.1, 140.2, 149.7, 177.5. Anal. Calcd. For C16H12N3ClSe:
C, 53.28 %; H, 3.35 %; N, 11.65 %. Found: C, 53.19 %; H,
3.26 %; N, 11.49 %.
4-Chloromethyl-[2-(2-phenyl-1,3-thiazolo-4-methylidene)-
hydrazinyl]-1,3-selenazole (2g) White crystals yield =
52 %, m.p. = 175–176 °C, IR (cm-1): 3289 (mNH); 2965
(mCH); 1603 (mC=N); 1570 (mC=Caromatic). MS (m/z):
381/383/384 (M?); 224; 182(100 %); 179; 134; 109; 92;
1
77; 64; 51; 39. H-NMR (300 MHz, DMSO-d6, d ppm):
4.78 (s, 2H, CH2Cl), 7.42 (s, 1H, CH–Se), 7.31 (s, 1H, CH–Th),
7.78 (t, 1H, C6H5-para, J = 7.6 Hz), 7.85 (t, 2H, C6H5-meta,
J = 7.6 Hz), 7.98 (d, 2H, C6H4-ortho, J = 7.6 Hz), 8.07 (s,
1H, CH=N), 11.59 (s, 1H, NH). 13C-NMR (75.5 MHz, DMSO-
d6, d ppm): 40.3, 116.3, 118.9, 125.0, 126.6, 126.7, 128.7,
128.8, 129.9, 134.3, 149.6, 151.1, 167.0, 171.4. Anal. Calcd.
for C14H11ClN4SSe: C, 44.05 %; H, 2.90 %; N, 14.68 %;
S, 8.40 %. Found: C, 44.02 %; H, 2.89 %; N, 14.63 %; S,
8.36 %.
5-Ethoxycarbonyl-4-methyl-2-[(4-chloro-benzyliden)-hy-
drazinyl]-1,3-selenazole (2d) Brown crystals yield =
59 %, m.p. = 197–198 °C, IR (cm-1): 3184 (mNH); 2980,
2862 (mCH); 1742 (mC=O ester); 1621 (mC=N); 1596
(mC=Caromatic). MS (m/z): 369/371/373 (M?); 326; 260;
234; 188; 160; 111; 89; 67; 42; 29(100 %). 1H-NMR
(400 MHz, DMSO-d6, d ppm): 1.23 (t, 3H, CH3,
J = 7.0 Hz), 2.37 (s, 3H, CH3), 4.14 (q, 2H, CH2,
J = 7.0 Hz), 7.47 (d, 2H, C6H4-meta, J = 8.4 Hz), 7.71
(d, 2H, C6H4-ortho, J = 8.4 Hz), 8.21 (s, 1H, CH=N),
10.52 (s, 1H, NH). 13C-NMR (100.5 MHz, DMSO-d6,
d ppm): 14.7, 16.8, 60.7, 128.7, 129.0, 129.3, 129.5,
133.7, 134.8, 137.2, 138.7, 157.4, 163.4, 174.8. Anal.
Calcd. for C14H14ClN3O2Se: C, 45.36 %; H, 3.81 %; N,
11.34 %. Found: C, 45.29 %; H, 3.36 %; N, 11.28 %.
4-Methyl-5-acetyl-[2-(2-phenyl-1,3-thiazolo-4-methylidene)
-hydrazinyl]-1,3-selenazole (2h) White crystals, yield =
57 %, m.p. = 169–170 °C, IR (cm-1): 3279 (mNH); 2935
(mCH); 1605 (mC=N); 1570 (mC=Caromatic). MS (m/z):
388/390/391 (M?); 224; 182(100 %); 179; 134; 109; 92;
1
77; 64; 51; 39. H-NMR (400 MHz, DMSO-d6, d ppm):
2.05 (s, 3H, CH3), 2.41 (s, 3H, CH3), 7.49–7.51 (m, 3H,
Ar–H), 7.94 (d, 2H, Ar–H; J = 7.6 Hz), 7.99 (s, 1H, CH–
Th), 8.22 (s, 1H, CH=N), 8.33 (s, 1H, NH). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 18.8, 24.5, 118.7, 126.4,
126.8, 127.0, 129.5, 129.9, 131.1, 133.2, 149.9, 152.8,
158.0, 160.0, 164.8, 167.7. Anal. Calcd. for C16H14N4O
SSe: C, 49.36 %; H, 3.62 %; N, 14.39 %; S, 8.23 %.
Found: C, 49.32 % H, 3.57 % N, 14.35 %; S, 8.20 %.
4-Methyl-[2-(4-methoxy-benzyliden)-hydrazinyl]-1,3-sele-
nazole (2e) Brown crystals, yield = 56 %, m.p. = 155–
157 °C. IR (cm-1): 3112 (mNH); 2924 (mCH); 1627
(mC=N) 1596 (mC=Caromatic). MS (m/z): 293/295/297 (M?);
162(100 %); 160; 134; 120; 92; 77; 64; 39. 1H-NMR
(300 MHz, DMSO-d6, d ppm): 2.36 (s, 3H, CH3), 3.81 (s,
3H, OCH3), 7.06 (d, 2H, C6H4-meta, J = 8.8 Hz), 7.12 (s, 1H,
CH–Se), 7.82 (d, 2H, C6H4-ortho, J = 8.8 Hz), 8.37 (s, 1H,
CH=N), 10.42 (s, 1H, NH). 13C-NMR (75.5 MHz, DMSO-d6,
d ppm): 18.9, 55.3, 114.6, 114.8, 115.2, 124.9, 128.1, 128.2,
138.4, 151.9, 161.8, 173.5. Anal. Calcd. for C12H13N3O2Se: C,
48.99 %; H, 4.45 %; N, 14.28 %. Found: C, 48.79 %; H,
4.41 %; N, 14.21 %.
General procedure for the preparation of 2-(N1-acetyl-
N2-aryliden-hydrazino)-1,3-selenazoles (3a–h)
2 mmol aryliden-hydrazinoselenazole (2a–h) was treated
with 2 ml acetic anhydride and 2 drops of pyridine. The
reaction mixture was refluxed for 5 min and then poured in
water. The precipitate was filtered and purified by recrys-
tallization from ethanol.
4-Phenyl-[2-(4-metoxybenzyliden)-hydrazinyl]-1,3-selenazole
(2f) White crystals, yield = 53 %, m.p. = 169–170 °C,
IR (cm-1): 3289 (mNH); 2965 (mCH); 1603 (mC=N); 1570
(mC=Caromatic). MS (m/z):353/357/359 (M?); 224; 182
(100 %); 179; 134; 109; 92; 77; 64; 51; 39. 1H-NMR
(400 MHz, DMSO-d6, d ppm): 3.77 (s, 3H, OCH3,), 6.98
(d, 2H, C6H4-meta, J = 8.6 Hz), 7.26 (t, 1H, C6H5-para,
J = 7.3 Hz), 7.36 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.58 (d,
2H, C6H5-ortho, J = 8.6 Hz), 7.81 (d, 2H, C6H4-ortho,
4-Methyl-2-[(4-chloro-benzyliden)-N-acetyl-hydrazinyl]-1,
3-selenazole (3a) White crystals, yield = 53 %, m.p. =
80–81 °C, IR (cm-1): 2978 (mCH); 1685 (mC=O amide);
1629 (mC=N). MS (m/z): 339/341/343 (M?); 299; 188; 162;
1
138; 111; 89; 75; 43(100 %); 39; 28. H-NMR (300 MHz,
DMSO-d6, d ppm): 2.23 (s, 3H, CH3), 2.63 (s, 3H, CH3),
123

Med Chem Res
4-Methyl-2-[(4-methoxybenzyliden)-N-acethyl-hydrazinyl]-
1,3-selenazole (3e) Brown-yellow, yield = 56 %, m.p. =
92–93 °C, IR (cm-1): 2926 (mCH); 1693 (mC=O amide);
1627 (mC=N); 1591 (mC=Caromatic). MS (m/z): 335/337/339
(M?); 259; 204; 162; 134; 120; 92; 77; 51; 43(100 %). 1H-
NMR (400 MHz, DMSO-d6, d ppm): 2.22 (s, 3H, CH3),
2.36 (s, 3H, CH3), 3.81 (s, 3H, OCH3), 7.06 (d, 2H, C6H4-
meta, J = 8.8 Hz), 7.36 (s, 1H, CH–Se), 7.82 (d, 2H,
C6H4-ortho, J = 8.8 Hz), 9.07 (s, 1H, CH=N). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 19.0, 23.0, 55.9, 115.0,
115.7, 125.9, 126.1, 128.5, 130.7, 147.1, 157.1, 162.8, 163.7,
170.6. Anal. Calcd. for C14H15N3O2Se: C, 50.01 %; H, 4.50 %;
N, 12.50 %. Found: C, 49.83 %; H, 4.46 %; N, 12.31 %.
7.45 (d, 2H, C6H4-meta, J = 8.7 Hz), 7.75 (d, 2H, C6H4-
ortho, J = 8.7 Hz), 8.23 (s, 1H, CH–Se), 9.61 (s, 1H,
CH=N). 13C-NMR (100.5 MHz, DMSO-d6, d ppm): 17.2,
22.15, 110.3, 126.9, 127.2, 128.5, 128.6, 133.3, 135.1,
145.8, 152.1, 154.6, 171.2. Anal. Calcd. for C13H12N3
ClOSe: C, 45.83 %; H, 3.55 %; N, 12.33 %. Found: C,
45.76 %; H, 3.52 %; N, 12.23 %.
4-Chloromethyl-2-[(4-chlorobenziliden)-N-acetyl-hydrazi-
nyl]-1,3-selenazole (3b) White crystals, yield = 52 %,
m.p. = 132–133 °C, IR (cm-1): 3041 (mCH); 1682 (mC=O
amide); 1628 (mC=N). MS (m/z): 373/375 (M?); 333; 196;
161; 124; 89; 43(100 %); 28. 1H-NMR (300 MHz, DMSO-
d6, d ppm): 2.18 (s, 3H, CH3), 4.63 (s, 2H, CH2Cl), 7.45 (d,
2H, C6H4-meta, J = 8.7 Hz), 7.75 (d, 2H, C6H4-ortho,
J = 8.7 Hz), 8.29 (s, 1H, CH–Se), 9.42 (s, 1H, CH=N).
13C-NMR (100.5 MHz, DMSO-d6, d ppm): 22.6, 40.3,
118.6, 127.3, 127.3, 128.4, 128.7, 133.1, 137.2, 144.3,
151.1, 154.3, 172.2. Anal. Calcd. for C13H11N3ClOSe: C,
41.62 %; H, 2.96 %; N, 11.20 %;. Found: C, 41.60 %; H,
2.93 %; N, 11.05 %.
4-Phenyl-2-[(4-methoxybenzyliden)-N-acetyl-hydrazinyl]-
1,3-selenazole (3f) White-yellowish crystals, yield =
61 %, m.p. = 140–142 °C, IR (cm-1): 2933 (mCH); 1678
(mC=O amide); 1624 (mC=N) 1593 (mC=Caromatic). MS (m/
z): 397/398/399 (M?); 357/266/224; 182; 135; 102; 77;
1
43(100 %). H-NMR (400 MHz, DMSO-d6, d ppm): 2.47
(s, 3H, CH3), 3.83 (s, 3H, OCH3), 7.10 (d, 2H, C6H4-meta,
J = 8.8 Hz), 7.25 (t, 1H, C6H5-para, J = 7.4 Hz), 7.34
(t, 2H, C6H5-meta, J = 7.4 Hz), 7.80 (d, 2H, C6H5-ortho,
J = 7.3 Hz), 7.89 (d, 2H, C6H4-ortho, J = 8.8 Hz), 8.24
(s, 1H, CH–Se), 9.33 (s, 1H, CH=N). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 23.0, 55.9, 115.1, 116.4,
126.0, 126.2, 128.0, 128.4. 129.0, 129.1, 130.6, 131.2,
134.8, 135.6, 149.1, 157.3, 162.8, 164.1, 171.1. Anal.
Calcd. for C19H17N3O2Se: C, 57.29 %; H, 4.30 %; N,
10.55 %. Found: C, 57.29 %; H, 4.21 %; N, 10.43 %.
4-Phenyl-2-[(4-chlorobenzyliden)-N-acetyl-hydrazinyl]-1,
3-selenazole (3c) White-yellowish crystals, yield = 68 %,
m.p. = 162–163 °C, IR (cm-1): 3072 (mCH); 1701 (mC=O
amide); 1630 (mC=N). MS (m/z): 401/403/405 (M?); 361;
1
266; 224; 182; 137; 102; 89; 77; 51; 43(100 %). H-NMR
(400 MHz, DMSO-d6, d ppm): 2.06 (s, 1H, CH3), 7.27
(t, 1H, C6H5-para, J = 7.3 Hz), 7.37 (t, 2H, C6H5-meta,
J = 7.6 Hz), 7.61 (d, 2H, C6H5-meta, J = 8.4 Hz), 7.82
(d, 2H, C6H4-ortho, J = 7.6 Hz), 7.95 (d, 2H, C6H4-ortho,
J = 8.4 Hz), 8.31 (s, 1H, CH–Se), 9.61 (s, 1H, CH=N).
13C-NMR (100.5 MHz, DMSO-d6, d ppm): 23.1, 117.3,
126.3, 126.8, 127.5, 128.1, 128.5, 129.2, 129.8, 130.3,
132.8, 135.2, 136.8, 149.3, 157.2, 159.7, 171.9. Anal. Calcd.
for C18H14ClN3OSe: C, 53.68 %; H, 3.50 %; N, 10.43 %.
Found: C, 53.41 %; H, 3.39 %; N, 10.24 %.
4-Chloromethyl-2-[(2-phenyl-1,3-thiazolo-4-methyliden)-
N-acetyl-hydrazinyl]-1,3–selenazole (3g) White crystals,
yield = 48 %, m.p. = 145–146 °C, IR (cm-1): 2936
(mCH); 1693 (mC=O amide); 1625 (mC=N); 1570 (mC=Caro-
matic). MS (m/z): 421/424/426 (M?); 382; 253; 190; 161;
121; 59; 43(100 %). 1H-NMR (300 MHz, DMSO-d6, d
ppm): 2.51 (s, 3H, CH3), 4.83 (s, 2H, CH2Cl), 7.58 (s, 1H,
CH–Th), 7.82 (t, 1H, C6H5-para, J = 7.3 Hz), 7.86 (t, 2H,
C6H5-meta, J = 7.5 Hz), 7.99 (d, 2H, C6H4-ortho, J =
7.5 Hz), 8.26 (s, 1H, CH–Se), 9.26 (s, 1H, CH=N).
13C-NMR (100.5 MHz, DMSO-d6, d ppm): 22.6, 40.3,
115.2, 118.5, 125.0, 126.3, 126.5, 128.8, 128.9, 130.0, 134.4,
149.5, 151.1, 155.3, 167.0, 171.4. Anal. Calcd. for C16H13
ClN4OSSe: C, 45.35 %; H, 3.09 %; N, 13.22 %; S, 7.57 %.
Found: C, 45.32 %; H, 3.02 %; N, 13.21 %; S, 7.51 %.
5-Ethoxycarbonyl-4-methyl-2-[(4-chlorobenzyliden)-N-acetyl-
hydrazinyl]-1,3-selenazole (3d) White-yellowish crystals,
yield = 48 %, m.p. = 132–133 °C, IR (cm-1): 3012
(mCH); 1712 (mC=O ester); 1672 (mC=O amide); 1621
(mC=N). MS (m/z): 411/413/416 (M?); 371; 326; 298; 234;
188; 160; 111; 89; 67; 43(100 %); 28. 1H-NMR (300 MHz,
DMSO-d6, d ppm): 1.42 (t, 3H, CH3, J = 6.9 Hz), 2.38
(s, 3H, CH3), 2.45 (s, 3H, CH3), 4.51 (q, 2H, CH2,
J = 6.9 Hz), 7.64 (d, 2H, C6H4-meta, J = 8.4 Hz), 7.92 (d,
2H, C6H4-ortho, J = 8.4 Hz), 8.28 (s, 1H, CH–Se), 9.63
(s, 1H, CH=N). 13C-NMR (100.5 MHz, DMSO-d6, d ppm):
14.3, 16.5, 22.4, 61.7, 128.3, 129.1, 129.5, 129.7, 133.5,
134.8, 137.1, 138.3, 157.4, 159.33, 163.4, 174.8. Anal.
Calcd. for C16H16ClN3O3Se: C, 46.56 %; H, 3.91 %; N,
10.18 %; Found: C, 46.12 %; H, 3.76 %; N, 10.02 %.
4-Methyl-5-acetyl-2-[(2-phenyl-1,3-thiazolo-4-methyliden-
N-acetyl-hydrazinyl]-1,3-selenazole (3h) White crystals,
yield = 49 %, m.p. = 191–193 °C, IR (cm-1): 3092 (mCH);
1691(mC=Ocetone); 1655(mC=O amide). MS(m/z):430/431/
432 (M?); 390; 342; 230; 188; 161; 121; 83; 57; 43(100 %).
1H-NMR (400 MHz, DMSO-d6, d ppm): 2.05 (s, 3H, CH3),
123

Med Chem Res
2.41 (s, 3H, CH3), 2.52 (s, 3H, CH3), 7.54 (t, 1H, C6H5-para,
J = 7.3 Hz), 7.59 (t, 2H, C6H5-meta, J = 8.8 Hz), 7.97 (d,
2H, C6H5-ortho, J = 8.8 Hz), 7.98 (s, 1H, CH–Th), 9.14 (s,
1H, CH=N). 13C-NMR(100.5 MHz, DMSO-d6, dppm): 18.6,
22.3, 24.2, 118.5, 126.6, 126.7, 127.0, 129.2, 129.3, 132.1,
133.4, 150.0, 152.6, 154.2, 158.1, 160.3, 164.5, 167.8. Anal.
Calcd. for C18H16N4O2SSe: C, 50.12 %; H, 3.74 %; N,
12.99 %; S, 7.43 %. Found: C, 50.09 %; H, 3.68 %; N,
12.75 %; S, 7.39 %.
2 mmol of a-halogenocarbonyl derivative was added. The
reaction mixture was stirred at room temperature for 24 h.
The precipitate formed after neutralization with NaHCO3
was collected by filtration. The product was purified by
recrystallization from ethanol.
4-Methyl-[2-(benzoyl-hydrazinyl)]-1,3-selenazole (5a) White
crystals, yield = 59 %, m.p. = 177–178 °C, IR (cm-1):
3423, 3201 (mNH); 3099, 2983 (mCH); 1661 (mC=O amide);
1593 (mC=Caromatic). MS (m/z): 279/281/283 (M?); 204;
General procedure for the synthesis of aroyl-
selenosemicarbazide (4a–b)
1
188; 162; 146; 105; 89; 77(100 %); 43; 39; 28. H-NMR,
(400 MHz, DMSO-d6, d ppm): 2.07 (s, 3H, CH3), 6.72 (s,
1H, CH–Se), 7.49 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.57 (t,
1H, C6H5-para, J = 7.3 Hz), 7.85 (d, 2H, C6H5-ortho,
J = 7.3 Hz), 9.61 (s, 1H, NH), 10.79 (s, 1H, NH). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 18.8, 105.9, 127.8, 128.0,
129.0, 129.1, 132.5, 132.9, 148.9, 166.6, 175.2. Anal. Calcd.
for C11H11N3OSe: C, 47.15 %; H, 3.96 %; N, 15.00 %.
Found: C, 47.03 %; H, 3.71 %; N, 14.96 %.
2 mmol (0.27 g) selenosemicarbazide was dissolved in
5 ml of NaOH 8 % aqueous solution and 2 mmol of a-
cylchloride was added. The reaction mixture was stirred at
room temperature for 1 h. Water was added until the vol-
ume became double and the solution was acidified with
acetic acid. The precipitate thus obtained was collected by
filtration. The purification was performed by recrystalli-
zation from water and ethanol in 1:2 volumetric ratios.
4-Phenyl-2-(benzoyl-hydrazinyl)-1,3-selenazole (5b) White
crystals, yield = 63 %, m.p. = 172–173 °C, IR (cm-1):
3426, 3204 (mNH); 3099, 2983 (mCH); 1663 (mC=O amide);
1593 (mC=Caromatic). MS (m/z): 341/343/345 (M?); 266; 238;
223; 162; 138; 120; 105; 77(100 %); 39; 28. 1H-NMR
(400 MHz, DMSO-d6, d ppm): 7.25 (t, 1H, C6H5-para,
J = 7.6 Hz), 7.35 (t, 2H, C6H5-meta, J = 7.6 Hz), 7.52 (t,
2H, C6H5-meta, J = 7.3 Hz), 7.60 (t, 1H, C6H5-para,
J = 7.3 Hz), 7.70 (s, 1H, CH–Se), 7.81 (d, 2H, C6H4-ortho,
J = 7.6 Hz), 7.88 (d, 2H, C6H4-ortho, J = 7.3 Hz), 9.81 (s,
1H, NH), 10.93 (s, 1H, NH). 13C-NMR (100.5 MHz, DMSO-
d6, d ppm): 108.2, 126.0, 126.3, 127.7, 127.9, 128.3, 128.3,
129.0, 129.1, 132.6, 132.7, 132.8, 136.0, 151.9, 168.0, 175.7.
Anal. Calcd. for C16H13N3OSe: C, 56.15 %; H, 3.83 %; N,
12.28 %. Found: C, 56.11 %; H, 3.79 %; N, 12.22 %.
Benzoyl-selenosemicarbazide (4a) White crystals, yield =
58 %, m.p. = 182–183 °C, IR (cm-1): 3343, 3271 (mNH);
3123, 2973, (mCH); 1679 (mC=O amide), 1521 (mC=Caro-
matic). MS (m/z): 240/242/244 (M?); 227; 166; 138(100 %);
105; 77; 50; 43; 28. 1H-NMR (400 MHz, DMSO-d6, d
ppm): 7.44 (t, 2H, C6H5-meta, J = 7.2 Hz); 7.53 (t, 1H,
C6H5-para, J = 7.2 Hz), 7.87 (d, 2H, C6H5-ortho, J =
7.2 Hz), 8.12 (s, 1H, NH), 8.26 (s, 1H, NH), 9.72 (s, 2H,
NH2). 13C-NMR (100.5 MHz, DMSO-d6, d ppm): 125.5,
128.3, 128.6, 129.7, 130.9, 132.1, 133.0, 165.9. Anal.
Calcd. for C8H9N3OSe: C, 39.68 %; H, 3.75 %; N,
17.35 %. Found: C, 39.63 %; H, 3.68 %; N,17.31 %.
p-Chloro-benzoyl-selenosemicarbazide (4b) White crys-
tals, yield = 65 %, m.p. = 199–200 °C, IR (cm-1): 3336,
3262 (mNH); 3133, 2985 (mCH); 1682 (mC=O amide); 1592
(mC=Caromatic). MS (m/z): 275/277/279, 280 (M?); 196;
4-Methyl-2-[(4-chlorobenzoyl)-hydrazinyl]-1,3-selenazole
(5c) White crystals yield = 67 %, m.p. = 189–190 °C,
IR (cm-1): 3415, 3211 (mNH); 3097, 2846 (mCH); 1660
(mC=O amide); 1596 (mC=C aromatic). MS (m/z): 313/315/
317 (M?); 204; 162; 146; 138; 111;77(100 %); 39; 28. 1H-
NMR (400 MHz, DMSO-d6, d ppm): 2.07 (s, 3H, CH3), 6.71
(s, 1H, CH–Se), 7.57 (d, 2H, C6H5-meta, J = 8.5 Hz), 7.86
(d, 2H, C6H4-ortho, J = 8.5 Hz), 9.65 (s, 1H, NH), 10.86 (s,
1H, NH). 13C-NMR (100.5 MHz, DMSO-d6, d ppm): 18.7,
105.7, 129.2, 129.8, 130.1, 131.6, 135.4, 137.3, 149.0, 165.5,
175.0. Anal. Calcd. for C11H10ClN3OSe: C, 41.99 %; H,
3.20 %; N, 13.36 %. Found: C, 41.99 %; H, 3.16 %; N,
13.29 %.
1
195; 152; 141; 139(100 %); 111; 75; 50; 43; 28. H-NMR
(400 MHz, DMSO-d6, d ppm): 7.53 (d, 2H, C6H5-meta,
J = 8.6 Hz), 7.87 (d, 1H, C6H5-ortho, J = 8.6 Hz), 8.2
(s, 1H, NH), 8.32 (s, 1H, NH), 9.72 (s, 2H, NH2). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 125.4, 128.1, 128.4, 129.7,
130.9, 132.1, 138.0, 165.9. Anal. Calcd. for C8H8N3ClOSe:
C, 34.74 %; H, 2.92 %; N, 15.19 %. Found: C, 34.56 %; H,
2.85 %; N, 15.10 %.
General procedure for the preparation of aroyl-hydrazinyl-
1,3-selenazole (5a–d)
4-phenyl-2-[(4-chlorobenzoyl)-hydrazinyl]-1,3-selenazole (5d)
White-yellowish crystals, yield = 63 %, m.p. = 196–197 °C,
2 mmol (0.26 g) of aroyl-selenosemicarbazide was dis-
solved in 5 ml DMF and 5 ml anhydrous acetone and then
123

Med Chem Res
IR (cm-1): 3410, 3212 (mNH); 3095, 2843 (mCH); 1665 (mC=O
amide); 1596 (mC=C aromatic). MS (m/z): 375/377 (M?);
299; 238; 223; 207; 169; 154; 146; 138; 77(100 %); 39; 28.
1H-NMR (400 MHz, DMSO-d6, d ppm): 7.25 (t, 1H, C6H5-
para, J = 7.3 Hz), 7.35 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.60
(d, 2H, C6H5-meta, J = 8.5 Hz), 7.70 (s, 1H, CH–Se), 7.80 (d,
2H, C6H4-ortho, J = 7.3 Hz), 7.90 (d, 2H, C6H4-ortho,
J = 8.5 Hz), 9.83 (s, 1H, NH), 11.00 (s, 1H, NH). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 108.6, 126.0, 126.3, 126.6,
127.0, 127.7, 129.0, 129.4, 129.6, 130.1, 131.5, 136.0, 137.5,
151.9, 165.9, 175.3. Anal. Calcd. for C16H12ClN3OSe: C,
51.02 %; H, 3.21 %; N, 11.15 %. Found: C, 51.00 %; H,
3.19 %; N,11.12 %; .
C20H17N3O3Se: C, 56.26 %; H, 3.93 %; N, 10.93 %.
Found: C, 56.21 %; H, 3.89 %; N, 10.85 %.
4-Methyl-2-[(4-chloro-benzoyl)-N,N-diacetyl-hydrazinyl]-
1,3-selenazole (6c) White crystals, yield = 52 %, m.p. =
200–202 °C, IR (cm-1): 3097, 2846 (mCH); 1660, 1631
(mC=O amide); 1596 (mC=C aromatic). MS (m/z): 357/359
(M?); 204; 162; 146; 138; 111;77; 43(100 %); 39; 28.
1H-NMR (400 MHz, DMSO-d6, d ppm): 2.32 (s, 3H, CH3),
2.41 (s, 3H, CH3), 2.46 (s, 3H, CH3), 7.35 (s, 1H, CH–Se),
7.55 (d, 2H, C6H5-meta, J = 8.5 Hz), 7.72 (d, 2H, C6H4-
ortho, J = 8.5 Hz). 13C-NMR (100.5 MHz, DMSO-d6, d
ppm): 18.7, 31.1, 32.4, 116.7, 129.0, 129.1, 130.1, 130.3,
133.2, 137.5, 146.9, 158.0, 169.2, 171.8, 172.0. Anal.
Calcd. for C15H14ClN3O3Se: C, 43.78 %; H, 3.39 %; N,
11.78 %. Found: C, 43.65 %; H, 3.36 %; N, 11.67 %.
General procedure for the preparation of 2-(N,N-
diacetyl-aroyl-hydrazinyl)-1,3-selenazole (6a–d)
2 mmol aroyl-hydrazino-selenazole (5a–d) was treated
with 2 ml acetic anhydride and 2 drops of pyridine. The
mixture was stirred at room temperature for 24 h. The
product was evaporated under vacuum to dryness and the
residue was recrystallized from ethanol.
4-Phenyl-2-[(4-chloro-benzoyl)-N,N-diacetyl-hydrazinyl]-
1,3-selenazole (6d) Yellow crystals, yield = 53 %,
m.p = 140–141 °C, IR (cm-1): 3095, 2843 (mCH); 1665,
1638 (mC=O amide); 1596 (mC=Caromatic). MS (m/z): 419,
421 (M?); 238/223/207; 169; 154; 146; 138; 43(100 %); 39;
1
28. H-NMR (400 MHz, DMSO-d6, d ppm): 2.40 (s, 3H,
4-Methyl-2-(benzoyl-N,N-diacetyl-hydrazinyl)-1,3-selenaz-
ole (6a) White crystals, yield = 51 %, m.p. = 163–
164 °C, IR (cm-1): 3099, 2983, 2846 (mCH); 1634, 1661
(mC=O amide); 1593 (mC=Caromatic). MS (m/z): 323/325
(M?); 281; 203; 188; 162; 146; 116; 77; 43(100 %); 39;
28.
1H-NMR (400 MHz, DMSO-d6, d ppm): 2.30 (s, 3H, CH3),
2.34 (s, 3H, CH3), 2.38 (s, 3H, CH3), 7.35 (s, 1H, CH–Se), 7.46
(t, 2H, C6H5-meta, J = 7.4 Hz), 7.56 (t, 1H, C6H5-para,
J = 7.4 Hz), 7.70 (d, 2H, C6H5-ortho, J = 7.6 Hz). 13C-NMR
100.5 MHz, DMSO-d6, d ppm): 18.7, 31.1, 37.5, 116.7, 129,0,
129.0, 129.1, 130,3, 133.2, 137.5, 146.9, 158.0, 169.2, 171.7,
171.9. Anal. Calcd. for C15H15N3O3Se: C, 48.46 %; H, 4.07 %;
N, 13.04 %. Found: C, 48.23 %; H, 4.02 %; N, 12.96 %.
CH3), 2.43 (s, 3H, CH3), 7.29 (t, 1H, C6H5-para,
J = 7.3 Hz), 7.37 (t, 2H, C6H5-meta, J = 7.3 Hz), 7.55
(d, 2H, C6H5-meta, J = 8.5 Hz), 7.80 (d, 2H, C6H4-ortho,
J = 7.3 Hz), 7.90 (d, 2H, C6H4-ortho, J = 8.5 Hz), 7.77 (s,
1H, CH–Se). 13C-NMR (100.5 MHz, DMSO-d6, d ppm):
24.5, 25.2, 118.1, 125.9, 125.9, 126.6, 126.7, 128.3, 128.9,
129.0, 129.3, 130.5, 132.9, 135.2, 137.8, 148.9, 158.5,
171.87, 172.06. Anal. Calcd. for C20H16ClN3O3Se: C,
51.63 %; H, 3.37 %; N, 10.03 %. Found: C, 51.52 %; H,
3.27 %; N, 10.00 %.
Cytotoxicity assay
Antitumor assay on Human DU-145 prostate carcinoma
and Hepatocarcinoma Hep-G2 cells
4-Phenyl-2-(benzoyl-N,N-diacetyl-hydrazinyl)-1,3-selenaz-
ole (6b) White crystals, yield = 53 %, m.p. = 155–
156 °C, IR (cm-1): 3099, 2983 (mCH); 1632, 1663 (mC=O
amide); 1593 (iC=Caromatic). MS (m/z): 385/387 (M?); 342;
266; 238; 223; 162; 138; 120; 105; 43(100 %); 39; 28. 1H-
NMR (400 MHz, DMSO-d6, d ppm): 2.41 (s, 3H, CH3),
2.44 (s, 3H, CH3), 7.24 (t, 1H, C6H5-para, J = 7.2 Hz),
7.33 (t, 2H, C6H5-meta, J = 7.8 Hz), 7.51 (t, 2H, C6H5-
meta, J = 7.2 Hz), 7.60 (t, 1H, C6H5-para, J = 7.8 Hz),
7.80 (s, 1H, CH–Se), 7.81 (d, 2H, C6H4-ortho, J =
7.2 Hz), 7.82 (d, 2H, C6H4-ortho, J = 7.8 Hz). 13C-NMR
(100.5 MHz, DMSO-d6, d ppm): 21.3, 24.4, 116.6, 126.0,
127.7, 127.9, 128.3, 129.0, 129.1, 132.6, 132.7, 132.8,
136.0, 151.9, 168.0, 166.9, 175.7, 175.9. Anal. Calcd. for
The cytotoxic activities of the samples were tested on
human DU-145 (androgen-insensitive prostate cancer cells)
and hepatocarcinoma Hep-G2 following the XTT (2,3-
bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-
carboxyanilide inner salt) assay (Gerlier and Thomasset,
1986; Zee-Cheng, 1997; Itharat et al., 2004). Briefly, DU-
145 and HepG-2 cells were cultured in Dulbecco’s mini-
mum essential medium (DMEM) supplemented with 5 %
fetal calf serum (FCS), gentamicin sulfate (0.004 %),
glucose (0.57 %), and NaHCO3 (0.12 %) (Complete
medium). Cells were seeded into 96-well flat-bottomed
plates at a concentration of 3.0 9 105 cells/ml. After 24 h,
cells were treated with samples, which were diluted with
123

Med Chem Res
Kantlehner W, Hauber M, Vettel MJ (1996) Orthoamides. IL.
Reactions of orthoamide derivatives with sulfur and selenium,
syntheses of 1,3-thiazole- and 1,3-selenazole derivatives. Prakt
Chem 338:403–413
Keil D, Hartmann H (2000) Preparation and characterisation of
2-amino-5-selenazolyl-substituted squaraines. Dyes Pigments
44:149–153
Kumar Y, Green R, Wise DS, Wotring LL, Townsend LB (1993)
Synthesis of 2,4-disubstituted thiazoles and selenazoles as
potential antifilarial and antitumor agents. 2. 2-Arylamido and
2-alkylamido derivatives of 2-amino-4-(isothiocyanatometh-
yl)thiazole and 2-amino-4-(isothiocyanatomethyl)selenazole.
J Med Chem 36:3849–3852
Lopez O, Maza S, Ulgar V, Maya I, Fernandez-Bolanos JG (2009)
Synthesis of sugar-derived isoselenocyanates, selenoureas, and
selenazoles. Tetrahedron 65:2556–2566
culture medium at various concentrations to a final range of
1.57–25 lM (Gerlier and Thomasset, 1986; Itharat et al.,
2004). XTT labeling reagent (50:1) was added and the
absorbance (560 nm) read after 72 h (Itharat et al., 2004).
Experiments were carried out three times in triplicate. The
concentration of the sample that inhibited 50 % cell pro-
liferation (IC50) was determined graphically. Doxorubicin,
a known antitumor agent, was used as positive control. The
cells survival percentage was determined by the formula:
% Survival Cell = (ODT/ODC) 9 100; ODT and ODC
being the absorbance of the test sample-treated group and
the control group (0.1 % DMSO), respectively. IC50 value
was the concentration of sample required to inhibit 50 % of
the cell proliferation and was calculated from a calibration
curve by a linear regression (Joshi et al., 2010) using
Microsoft Excel.
Naithani R (2008) Organoselenium compounds in cancer chemopre-
vention. Mini Rev Med Chem 8:657–668
Nam KN, Koketsu M, Lee EH (2008) 5-Chloroacetyl-2-amino-1,3-
selenazoles attenuate microglial inflammatory responses through
NF-kappaB inhibition. Eur J Pharm 589:53–57
Nguyen JT, Hoopes JD, Smee DF, Prichard MN, Driebe EM, Engelthaler
DM, Le MH, Keim PS, Spence RP, Went GT (2009) Triple
combination of oseltamivir, amantadine, and ribavirin displays
synergistic activity against multiple influenza virus strains in vitro.
Antimicrob Agents Chemother 53(10):4115–4126
Acknowledgments Financial support of this work by the Grant
CEEX nr.2 CEx-06-11-55/26.07.2006 is gratefully acknowledged.
References
Pire L, Deby-Dupont G, Lemineur T, Preiser JC (2007) How to keep
oxidative stress under control? Curr Nutr Food Sci 3:222–235
Akbaraly NT, Arnaud J, Haninger-Favier I, Gourlet V, Roussel AM,
Berr C (2005) Selenium and mortality in the elderly: results from
the EVA study. Clin Chem 51:2117–2123
Boik J (2001) Natural compounds in cancer therapy. Oregon Medical
Press, Princeton, pp 24–25
Brahemi G, Kona FR, Fiasella A, Buac D, Soukupov J, Brancale A,
Burger AM, Westwell AD (2010) Exploring the structural
requirements for inhibition of the ubiquitin E3 ligase breast
cancer associated protein 2 (BCA2) as a treatment for breast
cancer. J Med Chem 53:2757–2765
´ ´
Renson H (1956) Bulletin de Societes Chimiques Belges 65:684
Srivastava C, Robins RK (1983) Synthesis and antitumor activity of
2-beta-D-ribofuranosylselenazole-4-carboxamide and related
derivatives. J Med Chem 26:445–448
Ueda S, Terauchi H, Suzuki K, Matsumoto M, Kubo T, Minato H,
Arai Y, Tsuji J, Watanabe N (2005) Novel and orally bioavail-
able inducible nitric oxide synthase inhibitors: synthesis and
evaluation of optically active 4,5-dialkyl-2-iminoselenazolidine
derivatives. Bioorg Med Chem Lett 15:1361–1366
van der Goot H, Eriks JC, Leurs R, Timmerman
H (1994)
Gerlier D, Thomasset N (1986) Use of MTT colorimetric assay to
measure cell activation. J Immunol Methods 94(1/2):57–63
Goldstein M, Kennedy SD, Hennen WJ (1990) Selenium-77 NMR
and crystallographic studies of selenazofurin and its 5-amino
derivative. J Am Chem Soc 112:8265–8268
Amselamine, a new selective histamine H2-receptor agonist.
Bioorg Med Chem Lett 4:1913–1916
Wessjohann LA, Schneider A, Abbas M, Brandt W (2007) Selenium
in chemistry and biochemistry in comparison to sulfur. Biol
Chem 388(10):997–1006
Itharat A, Houghton PJ, Eno-Amooquaye E, Burke PJ, Sampson JH,
Raman A (2004) In vitro cytotoxic activity of Thai medicinal
plants used traditionally to treat cancer. J Ethnopharmacol
90(1):33–38
Zee-Cheng R (1997) Anticancer research on Loranthaceae plants.
Drugs Fut 22:519–530
Joshi SC, Verma AR, Mathela CS (2010) Antioxidant and antibac-
terial activities of the leaf essential oils of Himalayan Lauraceae
species. Food Chem Toxicol 48:37–40
123