Synthesis, determination of the lipophilicity, anticancer and antimicrobial properties of some fused 1,2,4-triazole derivatives

Article abstract of DOI:10.1016/j.ejmech.2007.03.033

3-Unsubstituted and 3-substituted-7-aryl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazoles (1-14) were designed and obtained from biologically active 1-aryl-2-hydrazonoimidazolidines by cyclocondensation reaction with triethyl orthoformates (1-4), phenoxyaceti

Full text of DOI:10.1016/j.ejmech.2007.03.033

Available online at www.sciencedirect.com
European Journal of Medicinal Chemistry 43 (2008) 404e419
http://www.elsevier.com/locate/ejmech
Short communication
Synthesis, determination of the lipophilicity, anticancer and
antimicrobial properties of some fused 1,2,4-triazole derivatives
b
c
a
Krzysztof Sztanke a, , Tomasz Tuzimski , Jolanta Rzymowska , Kazimierz Pasternak ,
*
d
´
Martyna Kandefer-Szerszen
a Chair and Department of Medical Chemistry, Professor Feliks Skubiszewski Medical University of Lublin, 4 Staszica Street, 20d081 Lublin, Poland
b Department of Physical Chemistry, Professor Feliks Skubiszewski Medical University, 6 Staszica Street, 20d081 Lublin, Poland
c Chair and Department of Biology and Genetics, Professor Feliks Skubiszewski Medical University, 6 Staszica Street, 20d081 Lublin, Poland
d Department of Virology and Immunology, Maria Curie-Skłodowska University, 19 Akademicka Street, 20d033 Lublin, Poland
Received 28 September 2006; received in revised form 17 February 2007; accepted 26 March 2007
Available online 14 April 2007
Abstract
3-Unsubstituted and 3-substituted-7-aryl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazoles (1e14) were designed and obtained from biologically
active 1-aryl-2-hydrazonoimidazolidines by cyclocondensation reaction with triethyl orthoformates (1e4), phenoxyacetic acid derivatives (5e
1
13) and carbon disulfide (14), respectively. Their chemical structures were confirmed by IR, H NMR, 13C NMR, MS spectra and elemental
analysis. In the high performance liquid chromatographic series of experiments, fourteen synthesized compounds (1e14) were chromatographed
on octadecyl silica adsorbent and their lipophilicity parameter (log kW) was determined using various aqueous systems: mixture of water and
organic modifiers (methanol e MeOH, acetonitrile e MeCN or dioxane e DX). Compounds 7 and 12 were evaluated for their cytotoxic activity
against three cancer cell lines: human Caucasian colon adenocarcinoma cell line e LS180 (ECACC 87021202), human uterus carcinoma cell
line e SiHa (ECACC 85060701) and human breast carcinoma cell line e T47D (ECACC 85102201). Compound 12 was found to be the most
effective in vitro against human colon adenocarcinoma cell line (LS180). Moreover, the distinctly marked lower cytotoxicity of compounds 7
and 12 against the normal cell line e human skin fibroblasts (HSF) and almost several-fold higher against the examined cancer cell lines was
ascertained. The cytotoxic effect of imidazotriazole 7 was noticed on DNA structure of breast cancer cell line (T47D) by using the comet assay.
Compound 7 in concentration of 29.3 mM was found to possess efficiency for DNA strand breakage. In particular, this led to cutting of the DNA
strands and formation of small fragments of DNA e two higher and one lighter in comparison with control DNA. Moreover, significant viability
decreases in the human leukaemic RPMI 8226 cells treated with different concentrations of imidazotriazoles 8e12 were observed, suggesting
their antiproliferative properties. Besides, three tested compounds (9, 13, 14) revealed significant antimicrobial activities with MIC values in the
range of 30.9e44.0 mM. Compound 13 showed superior antibacterial activity to ampicillin and chloramphenicol in vitro, whereas 14 displayed
superior antifungal activity to miconazole.
Ó 2007 Elsevier Masson SAS. All rights reserved.
Keywords: Imidazo[2,1-c][1,2,4]triazoles; Structure elucidation; Lipophilicity; Cytotoxicity; Anticancer activity studies; The comet assay; A novel DNA strand
breaking agent; Human colon adenocarcinoma cells (LS180); Human uterus cancer cells (SiHa); Human breast cancer cells (T47D); Human cervix epitheloid
carcinoma cells (HeLa); Human leukaemic RPMI 8226 cells; Antibacterial activity; Antimycotic activity
1. Introduction
There exist a number of [1,2,4]triazoles having a wide
range of pharmacological activities. The following [1,2,4]tria-
zole derivatives are applied in medicine: alprazolam (tranquil-
* Corresponding author. Tel.: þ48 81 5324002; fax: þ48 81 5323998.
E-mail address: krzysztof.sztanke@am.lublin.pl (K. Sztanke).
izer), estazolam (hypnotic, sedative, tranquilizer), rilmazafon
0223-5234/$ - see front matter Ó 2007 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2007.03.033

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
405
(hypnotic, anxiolytic, used in the case of neurotic insomnia),
R
R
R
R
benatradin (diuretic), trapidil (hypotensive), trazodon (antide-
pressant, anxiolytic), etoperidone (antidepressant), nefazodone
(antidepressant, 5-HT2 A-antagonist), anastrozole, letrozole,
vorozole (antineoplastics, nonsteroidal competitive aromatase
inhibitors), ribavirin (the potent antiviral N-nucleoside), fluco-
nazole, itraconazole, terconazole (the powerful azole antifun-
gal agents) [1].
a
N
N
NH
NH2
S
SH
d
NH2
N
NH
e
b
R
c
R
R
NH
It follows from the literature survey that, depending on the
type of substituent, the derivatives of [1,2,4]triazole have
a high potential for biological activity, possessing a wide range
of antimicrobial [2e5] and antitumour [6e9] properties. The
other ones show also anti-inflammatory [10], antihypertensive
[11], anticonvulsant and antiviral [12], analgesic [13] activities.
Our previous studies concerning bridgehead nitrogen-heterocy-
clic compounds obtained by fusion of the 4,5-dihydroimidazole
and [1,2,4]triazole nuclei, have identified one compound
containing the methylthio group at position 3 and with a 4-meth-
ylphenyl substituent at position 7 (e.g., 7-(4-methylphenyl)-3-
methylthio-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole) with
a significant antibacterial activity. This heterobicycle was
strongly active against Staphylococcus aureus ATCC 25923,
with a MIC value of 31.7 mM and showed superior antibacterial
activity to ampicillin [14]. On the other hand, a comprehensive
literature search showed that some derivatives having the
same heterocyclic skeleton, e.g., 7-aryl-5-methyl-3-thiolo-
imidazo[2,1-c][1,2,4]triazol-6-ones have been reported as pos-
sible antifungal agents. These bioactive compounds exhibited
fungicidal action almost equivalent to that of Mancozeb
(Dithane M-45) at 1000 ppm concentration and inhibited the
growth of Aspergillus niger and Fusarium oxysporum by
more than 48 and 47%, respectively, even at 10 ppm concen-
tration [15].
Prompted by these reports, and in continuation of our
search for bioactive molecules [14,16e19] and imidazo-fused
heterocycles revealing promising anticancer activities [20,21],
it seemed worthwhile to synthesize some novel biheterocyclic
derivatives containing the dihydroimidazole and [1,2,4]tria-
zole nuclei as possible compounds of high biological potency.
We report herein the synthesis, determination of the lipophilic-
ity of 3-unsubstituted and 3-substituted-7-aryl-5H-6,7-dihy-
droimidazo[2,1-c][1,2,4]triazole derivatives and testing results
of possible antitumour and antimicrobial active 3-phenoxy-
methyl and 3-thiolo-7-aryl-5H-6,7-dihydroimidazo[2,1-c]-
[1,2,4]triazole derivatives.
N
N
SCH3
HI
f
NHNH2
HI
CN
N
N
Scheme 1. Synthetic pathway for the preparation of starting 1-aryl-2-hydrazi-
noimidazolines. Reagents and conditions: (a) aziridine, AlCl3, dry toluene, (b)
HCHO, Na2S2O5, NaCN, water, reflux; (c) H2, NiRa, MeOHeNH3, 100 ꢀC;
(d) CS2, xylene, rt, 20 min, reflux, 7 h; (e) CH3IeMeOH, rt, 48 h, reflux,
6 h; (f) hydrazine hydrateeMeOH, reflux, 24 h.
Thus in the first step, commercially available anilines were
converted into N-arylethylenediamines by the Lehmann
method [22] or by the classical Knoevenagel and Mercklin
method with its further Takeda modification [23,24]. Their
further condensation with carbon disulfide in the xylene me-
dium led to the formation of intermediates e dithiocarbaminic
acid derivatives, which could easily be cyclized in boiling sol-
vent under reaction conditions to 1-arylimidazolidine-2-thio-
nes (1-aryl-2-mercaptoimidazolines) with concomitant loss
of hydrogen sulfide molecule. Because of existence of thi-
olethione tautomerism, the alkylation of respective thiols
with one equivalent methyl iodide was possible and afforded
1-aryl-2-methylthioimidazolines in 75e85% yields [14], these
in turn were refluxed with hydrazine hydrate to obtain 1-aryl-
2-hydrazinoimidazolines in good yields (65e76%). Finally
these compounds were used as the starting materials in the
synthesis of reported herein imidazotriazole derivatives (1e
14) (Scheme 2).
R
N
N
NH2
NH
R'
HO
O
b
CH2O
a
C
HC(OEt)3
R
CS2
c
2. Chemistry
R
R
The starting biologically active 1-aryl-2-hydrazonoimida-
zolidines (1-aryl-2-hydrazinoimidazolines), used in this study
were prepared by patent pending according to Sztanke from
N
N
N
N
N
N
N
N
N
R'
N
N
N
CH2O
SH
1-arylimidazolidine-2-thiones by
a
previously reported
1-4
5-13
14
method [16,19]. The four-step synthetic pathway for the prep-
aration of starting hydrazones was achieved by a sequence of
reactions starting from the respective anilines and is outlined
in Scheme 1.
Scheme 2. Synthetic route to obtain final imidazotriazoles of the type 1e14.
Conditions: (a) DMF, reflux, 6 h; (b) DMF, reflux, 6 h, NaOH (6%); (c)
MeOH, NaOHewater, rt, 30 min, reflux (water bath), 14 h. R and R0 as shown
in Table 1.

406
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
Cyclocondensation of 1-aryl-2-hydrazonoimidazolidines
61.9 ppm in the 13C NMR spectra of compounds 6e13, respec-
tively. Also, both quaternary triazole-C-3 and C-7a carbon
atoms signals were recorded at ca. 138.1 ppm and 159.3 ppm,
respectively, in their 13C NMR spectra.
The IR spectra confirmed the structure of the compounds
investigated. The examined compounds can be recognized
by the presence of specific absorption bands of the C]N moi-
ety in the range of 1607e1619 cmꢁ1. The absence of any Ne
H characteristic bands in the shorter wavelength region (ca.
3400 cmꢁ1) suggests their cyclic structure.
EI mass spectra (EIMS) of compounds 1e5 and 8e12 pro-
vided their molecular ion peaks at m/z: 186, 216, 220, 254,
292, 340, 354, 360, 374 and 394, respectively, with intensities
that varied from 4.5 to 100% confirming their molecular
weights. The molecular ion for compounds 3, 4, 8e12 was
calculated according to 35Cl isotope. The data are presented
in Section 5.
with triethyl orthoformate or derivatives of phenoxyacetic
acid in refluxing DMF afforded the corresponding 3-unsubsti-
tuted (1e4) or 3-phenoxymethyl (5e13) 7-aryl-5H-6,7-dihy-
droimidazo[2,1-c][1,2,4]triazoles, after a ring closure with
concomitant loss of ethanol or hydrogen oxide molecule,
respectively. Also, boiling of 1-(4-chlorophenyl)-2-hydrazonoi-
midazolidine with CS2 in aqueous KOH resulted in 7-(4-chlor-
ophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole-3-thiol
(14) in 76.1% yield with concomitant loss of hydrogen sulfide
molecule.
The majority of final products were obtained as previously
described [17e19], with the exception of compounds 4, 10e
12 whose synthesis has not been described in the literature
as yet. These compounds were generated according to the syn-
thetic method described by Sztanke et al. [17,18] with its fur-
ther modification. Thus, the highest yields for final
imidazotriazole derivatives were achieved, when the reaction
could be carried out starting from the free bases of 1-aryl-2-
hydrazonoimidazolidine, instead of their hydroiodide salts.
In this way improved yield values for compounds 1e3, 5e9
and 13e14 were obtained. The physicochemical, infrared
3. Lipophilicity results
Inthehighperformanceliquidchromatographic(HPLC)series
of experiments, fourteen derivatives of 3-(un)substituted-7-aryl-
5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (Table 1) were
chromatographedonoctadecylsilicaadsorbent(SUPELCOSILÔ
LC-18) using various aqueous systems: mixtures of water and
organic modifiers (methanol e MeOH, acetonitrile e MeCN or
dioxane e DX). Diethylamine (DEA) and phosphate buffer
(pH ¼ 3.5) were added to mobile phase (eluent containing
0.05 MLꢁ1 DEA in organic modifier (MeOH, MeCN or DX) e
buffered mobile phase).
The investigated compounds, such as heterocyclic bases,
e.g., alkaloids are difficult for chromatographic analysis.
Since the investigated compounds appear in solutions as
ionized and unionized forms, they are difficult for chromato-
graphic separation. Mobile phase pH is a major factor for
the separation of analytes with acidebase properties [25e29].
Retention models of ionizable solutes in liquid chro-
matography with a function of pH and solvent composition
1
(IR) data and H NMR, 13C NMR resonances and mass spec-
troscopic analyses (EIMS) of the compounds synthesized are
presented in Section 7.
A general synthesis of final imidazo[2,1-c][1,2,4]triazole
derivatives is shown in Scheme 2.
In view of continuous and widespread interest in the design
and the synthesis of novel heterocyclic derivatives containing
a [1,2,4]triazole moiety, the synthetic approach leading to the
formation of biheterocyclic dihydroimidazo[2,1-c][1,2,4]tria-
zole derivatives, described by us, might be considered as a useful
method for the preparation of these biologically active com-
pounds because of the affordability of the starting materials,
good yields obtained and straightforward product isolation.
NMR spectral characteristic of derivatives of the bihetero-
cyclic, polynitrogenated dihydroimidazotriazole system (1e
5, 10e14), revealed in their 1H NMR spectra the two
double-doublet signals of the H5 and H6 at ca. 4.34 and
4.58 ppm, with the coupling constants of J w 7.3 Hz,
J0 w 6.1 Hz, respectively, or multiplet signals in the range of
3.77e4.55 ppm in the spectra of compounds 6e9. The differ-
ence between chemical shifts of both signals can suggest an
important difference in the acidity of hydrogen atoms, which
was confirmed by the chemical shift values of respective car-
bon atoms in their 13C NMR spectra (ca. 39.8 ppm for the C-5
and 53.3 ppm for the C-6). Apart from the signals of aromatic
hydrogen atoms observed at aromatic region (6.97e
7.65 ppm), the two additional singlet signals: first from the
methylene protons derived from the phenoxymethylene forma-
tion (eCH2OPh) and second from the triazole-CH were ob-
´
were described by Soczewinski [30,31] and reviewed by
Schoenmakers and co-workers [32]. The theory of RP reten-
tion for ionic compounds with a function of pH assumes that
a given solute exists in ionized and non-ionized forms and in-
teracts by two different modes with chromatographic system
components.
Basic analytes can interact with silanol groups of silica ma-
trix, which can remain underivatised on bonded RP stationary
phases [33]. Silica is also the most widely used material in
chromatography. Silica supports are still superior to other sup-
ports in terms of efficiency, rigidity and performance.
Protonated basic compounds can interact with residual sila-
nol groups of the stationary phase, as shown in the equation:
1
served at ca. 5.26 ppm in the H NMR spectra of compounds
of the type 5e13 and at about 8.18 ppm in the 1H NMR spectra
of compounds 1e4, integrating for two protons and one proton,
respectively. The signals belonging to the methylene secondary
carbon atoms derived from the phenoxymethylene formation
were seen at 60.8, 60.9, 60.8, 60.9, 60.8, 60.9, 61.7,
XHþ þ SiOꢁNaþ 4 Naþ þ SiOꢁXHþ
Thus, besides the reversed phase retention mechanism an ion-
exchange retention mechanism also occurs, which often

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
407
Table 1
Chemical structures of 3-(un)substituted-7-aryl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazoles whose lipophilicities were determined
R
R
N
N
N
N
N
N
R'
N
N
CH2O
R'
1-4, 14
5-13
No.
Compound
7-Phenyl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
7-(4-Methoxylphenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4] triazole
R
R0
pKa1
pKa2
1
H
H
5.00
3.07
2.97
2.91
2.95
2.97
2.94
2.95
2.96
2.87
2.88
2.85
2.79
2.74
3.02
ꢁ4.16
e
2
4-OCH3
4-Cl
H
3
7-(4-Chlorophenyl)- 5H-6,7-dihydroimidazo[2,1-c][1,2,4] triazole
7-(3,4-Dichlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-Phenoxymethyl-7-phenyl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
H
4
3,4-Cl2
H
H
e
5
H
4-Cl
2.03
ꢁ4.34
2.03
ꢁ4.30
ꢁ4.28
e
6
3-(4-Chlorophenoxymethyl)-7-(4-methoxyphenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-[(2-Methyl-4-chloro)phenoxymethyl]-7-phenyl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-(4-Chlorophenoxymethyl)-7-(4-methylphenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-[(2-Methyl-4-chloro)phenoxymethyl]-7-(4-methylphenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-(4-Chlorophenoxymethyl-7-(4-chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-[(2-Methyl-4-chloro)phenoxymethyl]-7-(4-chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-(2,4-Dichlorophenoxymethyl)-7-(4-chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
3-(2,4-Dichlorophenoxymethyl)-7-(3,4-dichlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
7-(4-Chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole-3-thiol
4-OCH3
H
7
2-CH3; 4-Cl
4-Cl
8
4-CH3
4-CH3
4-Cl
9
2-CH3; 4-Cl
4-Cl
10
11
12
13
14
4-Cl
4-Cl
2-CH3; 4-Cl
2,4-Cl2
2,4-Cl2
SH
e
e
3,4-Cl2
4-Cl
e
e
results in asymmetry of peaks, irreproducible retention and
worse separation.
blocking of free silanols the peak shape of chromatographed
derivatives are improved.
Strong silanophilic interactions that can occur with these
analytes and the adsorbent surface can lead to poor peak
shape. In systems containing solely mixtures of water and or-
ganic modifier the peaks of chromatographed derivatives were
tailing and asymmetric. Silanol interaction can be reduced,
e.g., in chromatography of basic compounds by addition of
a more basic compound, which interacts more strongly with
residual silanols, allowing the less basic compound to interact
solely with the alkyl ligand of the stationary phase [34]. Sila-
nol interaction can be also reduced by using mobile phase of
a high pH (>7.0), when the ionization of some determined ba-
sic compounds is suppressed [35]. Diethylamine (DEA) was
added as silanol blocker to the eluent. To protect the stationary
phases, buffered mobile phases were applied.
The pKa values of investigated compounds have been eval-
uated by Pallas 3.1.1.2 software [36], and these have been used
to choose optimal composition of mobile phase. The structures
and pKa values of the above mentioned compounds are shown
in Table 1. In the structure of investigated compounds, there
are basic nitrogen atoms in positions 4 and 7 of heterobicycle
for which the pKa1 values are in the range of 2.74e5.00. The
pKa2 values of the compounds lie between ꢁ4.34 and 3.02.
The pKa values indicate that the analytes are very weakly ba-
sic. The pH values of used mobile phases after addition of di-
ethylamine and acetate buffer at pH ¼ 3.5 were higher than the
pKa basic analyte þ 1.5 (lies between 7.5 and 10) so that the basic
investigated compounds were completely unionized. In addi-
tion, diethylamine caused blocking of residual silanol groups.
Owing to application of ion suppression of analytes and
The experimental data obtained for reversed phase HPLC
systems: the intercepts (log kW), slopes (S ), regression coeffi-
cients (r), F statistic and standard errors (s) calculated for the
95% confidence level are presented in Table 2. The log kW
value is widely known as a lipophilicity parameter and is often
used for QSAR studies. The log kW values of the compounds
increase with addition of non-polar groups for reversed phase
chromatographic systems, for example, the addition of non-
polar substituents, e.g., eCl [37]. Comparison of the log kW
values for the investigated derivatives, in general, indicates
that the highest lipophilicity was observ ed for compounds
with 4-Cl and 3,4-Cl2 substituents. Compound 13 had the high-
est log kW values in aqueous systems with methanol and diox-
ane. The influence was by the eCl substituent at R and the
values of log kW increased generally in all RP chromatographic
systems (5e13) in the order R ¼ 4-Cl and R0 ¼ eH < R ¼ 4-Cl
and R0 ¼ 4-Cl < R ¼ 4-Cl and R0 ¼ 2-CH3, 4-Cl < R ¼ 4-Cl
and R0 ¼ 2,4-Cl2 < R ¼ 3,4-Cl2 and R0 ¼ 2,4-Cl2.
Fig. 1 presents the correlation between log kW values, de-
termined in dioxaneewater system, and log P values calcu-
lated by using Pallas 3.1.1.2 software [36]. The values of
log P of the solutes 8, 10e13 increased generally with addi-
tional substituent (4-CH3 or 4-Cl), especially with R ¼ 3,4-
Cl2 and R0 ¼ 2,4-Cl2. The solutes 8, 10e13 had log P values
higher with additional substituent (eCH3 or eCl), correspond-
ing with their higher values of log kW.
Attempts to correlate the chromatographic lipophilicity pa-
rameters with log P values calculated with some computer
programs failed; apparently, the structures of the compounds

408
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
Table 2
Terms of the equation log k ¼ log kW ꢁ S4 for the compounds investigated on
6
13
y = 0.6146x + 2.382
r = 0.6707
12
an octadecyl silica column (LC-18) with aqueous mobile phases
11
8
5
4
3
2
1
0
10
No.
log kW
S
r
F
s
n
9
DXeH2Oe20% buffer pH 3.5 containing 0.05 M Lꢁ1 DEA
7
1
1.16 ꢂ 0.09
1.22 ꢂ 0.08
1.89 ꢂ 0.09
2.49 ꢂ 0.08
1.78 ꢂ 0.11
1.52 ꢂ 0.13
1.17 ꢂ 0.09
3.55 ꢂ 0.20
1.10 ꢂ 0.05
3.41 ꢂ 0.19
3.87 ꢂ 0.21
4.15 ꢂ 0.21
4.61 ꢂ 0.16
ꢁ0.09 ꢂ 0.07
4.43 ꢂ 0.36
4.67 ꢂ 0.33
4.88 ꢂ 0.31
5.57 ꢂ 0.25
4.43 ꢂ 0.46
6.81 ꢂ 0.98
4.43 ꢂ 0.37
6.48 ꢂ 0.49
4.45 ꢂ 0.23
5.84 ꢂ 0.36
6.40 ꢂ 0.41
6.67 ꢂ 0.41
6.39 ꢂ 0.25
3.60 ꢂ 0.30
0.9900
0.9927
0.9922
0.9970
0.9894
0.9898
0.9900
0.9971
0.9987
0.9944
0.9939
0.9945
0.9978
0.9896
148.11
204.56
252.76
495.38
92.96
0.1041
0.0934
0.1198
0.0792
0.1233
0.1060
0.1050
0.0696
0.0320
0.1137
0.1294
0.1285
0.0596
0.0865
5
5
6
5
4
3
5
5
3
5
5
5
5
5
2
6
3
14
5
4
4
5
3
6
48.11
7
146.24
173.58
385.37
264.33
245.10
269.28
667.43
141.86
8
1
2
9
10
11
12
13
14
-1
0
1
2
3
4
5
MeCNeH2Oe20% buffer pH 3.5 containing 0.05 M Lꢁ1 DEA
log kw (DX - H2O - 20% buffer pH 3.5 + 0.05 mL-1 DEA)
1
1.37 ꢂ 0.10
1.56 ꢂ 0.11
2.70 ꢂ 0.17
2.11 ꢂ 0.27
1.37 ꢂ 0.11
1.54 ꢂ 0.13
1.36 ꢂ 0.11
3.04 ꢂ 0.26
1.00 ꢂ 0.16
3.23 ꢂ 0.23
3.70 ꢂ 0.21
3.75 ꢂ 0.25
3.32 ꢂ 0.25
4.78 ꢂ 0.41
5.54 ꢂ 0.44
8.01 ꢂ 0.66
4.52 ꢂ 0.67
4.78 ꢂ 0.42
5.37 ꢂ 0.50
4.74 ꢂ 0.43
5.10 ꢂ 0.57
3.87 ꢂ 0.61
5.26 ꢂ 0.47
5.81 ꢂ 0.43
5.81 ꢂ 0.53
3.76 ꢂ 0.35
e
0.9891
0.9906
0.9900
0.9785
0.9888
0.9873
0.9880
0.9879
0.9644
0.9921
0.9945
0.9918
0.9873
e
135.67
157.68
148.41
45.04
0.0987
0.1062
0.1585
0.1993
0.1005
0.1201
0.1029
0.1266
0.1891
0.1125
0.1029
0.1264
0.0551
e
5
5
5
4
5
5
5
5
4
4
4
4
5
e
2
Fig. 1. Correlation between log kW values for reversed mobile phases (dioxa-
neewater e 20% buffer pH 3.5 containing 0.05 M Lꢁ1 DEA) on the octadecyl
silica column (LC-18) and log P values calculated by using Pallas 3.11.2
software.
3
4
5
131.41
116.23
122.93
81.22
6
7
8
The high values of r (r > 0.9644) prove the excellent fit be-
tween experimental data and the logarithmic equation. The
values of the F statistic are always higher than the critical
value F, thus proving additionally a good fit of the data with
the examined model.
9
36.05
10
11
12
13
14
124.34
181.42
120.22
116.14
e
e
MeOHeH2Oe20% buffer pH 3.5 containing 0.05 M Lꢁ1 DEA
1
1.62 ꢂ 0.10
1.87 ꢂ 0.13
2.19 ꢂ 0.09
2.92 ꢂ 0.08
1.62 ꢂ 0.08
1.88 ꢂ 0.12
1.62 ꢂ 0.08
4.27 ꢂ 0.19
1.58 ꢂ 0.03
4.38 ꢂ 0.19
4.61 ꢂ 0.20
4.85 ꢂ 0.16
6.00 ꢂ 0.16
3.42 ꢂ 0.23
3.93 ꢂ 0.28
3.71 ꢂ 0.17
4.38 ꢂ 0.15
3.42 ꢂ 0.19
3.96 ꢂ 0.28
3.43 ꢂ 0.19
5.37 ꢂ 0.26
3.21 ꢂ 0.07
5.49 ꢂ 0.27
5.56 ꢂ 0.27
5.72 ꢂ 0.21
6.77 ꢂ 0.23
e
0.9910
0.9876
0.9968
0.9983
0.9927
0.9879
0.9926
0.9965
0.9991
0.9964
0.9977
0.9986
0.9983
e
219.31
197.26
469.18
860.76
340.18
202.49
331.89
422.80
2112.1
416.66
439.00
722.13
874.52
e
0.1115
0.1481
0.0542
0.0472
0.0982
0.1471
0.0995
0.0826
0.0292
0.0851
0.0594
0.0476
0.0362
e
6
7
5
5
7
7
7
5
6
5
4
4
5
e
4. Pharmacology
2
3
4
4.1. Antitumour screening studies
5
6
The newly synthesized compounds 7, 12 were evaluated for
their anticancer activity towards human tumour cell lines de-
rived from various human cancer types (colon, breast, uterus):
LS180 (ECACC 87021202, human Caucasian colon adenocar-
cinoma cells), SiHa (ECACC 85060701, uterus cancer cells),
T47D (ECACC 85102201, human breast carcinoma cells).
Furthermore, both normal cell lines were included in the cyto-
toxicity study: HSF (human skin fibroblast) cells e primary
cell line and Vero (ECACC 88020401, African Green Monkey
Kidney cells, GMK clone).
We have also investigated the changes in survival of human
leukaemic RPMI 8226 cells and HeLa cancer cells, induced by
the designed imidazotriazole derivatives (1e3, 5e12) in order
to choose the compounds having promising antiproliferative
properties. Their influence on normal human skin fibroblast
(HSF) cells was also determined.
7
8
9
10
11
12
13
14
e
investigated are too complex for the programs available. The
computer program [36] cannot discern different positions: or-
tho, meta and para of eCl substituent. The solutes 7 and 9, be-
longing to the examined 3,7-disubstituted imidazotriazoles,
which have log P relatively much higher than the correspond-
ing log kW can be given as example. The solutes 1e4, 14 lack-
ing eCH2OPh formation at R0 have the lowest values of log P
and the values of log P corresponding with their small values
of log kW. The regression equation for compounds 1e14 was
log P ¼ 0.6146 log kW þ 2.382 and the correlation coefficient
was found to be r ¼ 0.6707.
4.2. Antimicrobial studies
The lipophilicity of the compounds imperceptibly increases
with the eOCH3 group in reversed phases systems (relative
value of k is 1.1 for 30% MeCN [37]), e.g., solute 6.
Determination of the in vitro antimicrobial activity of the
compounds tested was performed using the microdilution
method, according to the National Committee for Clinical

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
409
Table 3
Inhibition of in vitro normal and cancer cells growth by imidazotriazoles 7 and
12
Laboratory Standards (NCCLS) [38e40] and the disc-diffu-
sion method by KirbyeBauer [40e43].
The in vitro activities of three examined compounds (9, 13,
14) against pathogenic bacteria, yeast-like fungi and moulds
were compared. The following microorganisms were used:
S. aureus ATCC 25923, Staphylococcus epidermidis, Strepto-
coccus pyogenes, Streptococcus agalactiae (Gram-positive
bacteria), Escherichia coli ATCC 25922, Pseudomonas aerugi-
nosa ATCC 27853, Proteus vulgaris, Klebsiella pneumoniae,
Enterobacter aerogenes (Gram-negative bacteria), Candida al-
bicans ATCC 10231 (yeast-like fungus), Aspergillus spp.
(moulds). The majority of strains under study were clinical
isolates, identified with conventional morphological and bio-
chemical methods.
The microdilution method for estimation of MIC values
(the lowest concentration of compounds required to inhibit
the growth of the tested microorganism) was applied to evalu-
ate the antimicrobial activity. In this method the two reference
strains of bacteria e S. aureus ATCC 25923, P. aeruginosa
ATCC 27853 and one reference fungal strain e C. albicans
ATCC 10231 were included in this study. The antibacterial
(9, 13) and antifungal (14) potencies of the compounds were
compared with the activities of topical antibacterial (ampicil-
lin, chloramphenicol) and antifungal (miconazole) drugs.
Cell line
Cytotoxicity (growth inhibition in %)
7
12
I
II
I
II
Normal cell lines
HSF
GMK
4
20
8
20
7
20
10
28
Cancer cell lines
LS180
SiHa
35
30
25
39
30
40
48
35
28
54
41
48
T47D
HSF e human skin fibroblast cells e primary cell line; Vero (GMK, ECACC
88020401, African Green Monkey Kidney cells); LS180 (ECACC 87021202)
e human Caucasian colon adenocarcinoma cells; SiHa (ECACC 85060701) e
uterus cancer cells; T47D (ECACC 86012201) e human breast carcinoma
cells; I e concentration of 10 mg mLꢁ1, which correspond to concentration
of 29.3 mM for compound 7 and 25.3 mM for compound 12; II e concentration
of 50 mg mLꢁ1, which correspond to concentration of 146.7 mM for compound
7 and 126.7 mM for compound 12.
particularly when it was applied in higher concentration. Sim-
ilarly, compound 7 exhibited 35 and 39% growth inhibition,
respectively, in both tested concentrations against human co-
lon adenocarcinoma cell line (LS180), whereas 12 showed
similar inhibitory effect on SiHa cancer cell line. Its growth in-
hibition values were found to be 35 and 41%, respectively, at
both examined concentrations: 25.3 mM (10 mg mLꢁ1) and
126.7 mM (50 mg mLꢁ1). Compound 12, in comparison to 7,
was more potent against uterus cancer cells (SiHa) in both
tested concentrations and against human breast carcinoma
cell line T47D in higher examined concentration. Compound
7 was the most active against human Caucasian colon adeno-
carcinoma cell line (LS180) at both examined concentrations:
29.3 mM (10 mg mLꢁ1) and 146.7 mM (50 mg mLꢁ1) and
against human breast carcinoma cell line T47D at a concentra-
tion of 146.7 mM (50 mg mLꢁ1). Both examined heterobi-
cycles (7, 12) are the 3-phenoxymethyl-7-aryl-5H-6,
7-dihydroimidazo[2,1-c][1,2,4]triazole derivatives and these
molecules differ from in the presence of a methyl (7) or
a chloro (12) substituent in ortho position of the phenoxy-
methylene formation and in the location of a chloro substituent
at para position of the phenyl ring (12) or its lack in the case
of compound 7. Compounds 7 and 12 showed different log kW
values of 1.17 and 4.15, respectively, in dioxaneewater sys-
tem. It was found that the introduction of a chloro substituent
to the phenyl ring, and the replacement of a methyl substituent
by a chloro substituent at the 2-position of the phenyl ring, that
of the phenoxymethylene formation in the case of compound
12 led to significant increase in lipophilicity (log kW ¼ 4.15
in aqueous system with dioxane) and influenced in increase
of anticancer activity. Moreover, the distinctly marked lower
cytotoxicity of derivatives 7 and 12 against normal cell lines
(human skin fibroblast cells e HSF and Vero African Green
Monkey Kidney cells e GMK clone) and almost several-
fold higher against the majority of cancer cell lines was ascer-
tained (Table 3 and Figs. 2e6). Taking into consideration the
5. Results and discussion
5.1. Antitumour activity studies
Compounds 7 and 12 were evaluated for their anticancer
activity. Results for each test agent are reported as the growth
inhibition percentage of treated cells when compared to the
untreated control ones. Compounds, which reduced the
growth, are passed on for evaluation towards three human can-
cer and two normal cell lines. Compounds 7 and 12 were
found to be active. These compounds were proved to exhibit
different levels of anticancer properties. According to the re-
sults listed in Table 3, compound 12 was found to be the
most active against the human Caucasian colon adenocarci-
noma cell line (LS180), reaching comparative growth inhibi-
tion values (48 and 54%) for each tested concentration:
25.3 mM (10 mg mLꢁ1) and 126.7 mM (50 mg mLꢁ1), respec-
tively. Moreover, it’s distinctly marked lower cytotoxicity to-
wards normal cell lines, especially towards human skin
fibroblasts (HSF) and almost seven-fold higher against
LS180 cancer cells in
a
concentration of 25.3 mM
(10 mg mLꢁ1) was ascertained. This compound was also found
to be above five-fold higher cytotoxic against LS180 cancer
cell line than towards normal cell line e HSF in a concentra-
tion of 126.7 mM (50 mg mLꢁ1). Compound 12 was about 1.7
times and 1.4 times more active against human Caucasian co-
lon adenocarcinoma cell line (LS180) than against human
breast carcinoma cell line (T47D) and uterus cancer cell line
(SiHa), respectively, at a single concentration of 25.3 mM
(10 mg mLꢁ1). On the contrary, both, human colon adenocarci-
noma cell line (LS180) and human breast cancer cell line
(T47D) showed similar susceptibility levels to this compound,

410
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
HSF
LS180
60
40
20
0
60
I – concentration of 10 µg mL-1
II – concentration of 50 µg mL-1
I – concentration of 10 µg mL-1
II – concentration of 50 µg mL-1
I
II
I
II
40
20
0
7
12
7
12
Compounds
Compounds
Fig. 4. Inhibition of in vitro human Caucasian colon adenocarcinoma cell line
(LS180) growth (expressed as growth inhibition percentage) by tested imida-
zotriazoles 7 and 12 in both examined concentrations (10 and 50 mg mLꢁ1).
Fig. 2. Cytotoxicity of tested imidazotriazoles 7 and 12 in both examined con-
centrations (10 and 50 mg mLꢁ1) towards human skin fibroblast (HSF) cell line
expressed as the growth inhibition (in %).
Compound 7 affected the superoxide dismutase (SOD)
gene expression in two cancer cells: LS180 and T47D
(Fig. 7). Furthermore, the effect of the tested heterobicycle 7
was noticed on DNA structure of the human breast cancer
cell line (T47D) by using the comet assay, which is shown
in Photo 1. This sensitive and rapid microelectrophoretic tech-
nique, also called the single cell gel assay (SCG) and microgel
growth inhibition comparative study results concerning the in-
fluence of the tested compounds on cancer and normal cell
lines, the selective action of the examined compounds can
be expected .
It has been reported that compounds having [1,2,4]triazole
moieties appear to bevery effective inhibitors of many enzymes,
for instance glycolytic, Krebs cycle enzymes in terms for pre-
venting digestive tract cancer. It is known that [1,2,4]triazole
moieties interact strongly with the heme iron and aromatic
substituents in the active site of aromatase. Three drugs e non-
steroidal, competitive aromatase inhibitors e anastrozole, letro-
zole and vorozole (belonging to the [1,2,4]triazole derivatives)
have been approved by the American food and drug administra-
tion (FDA) for first-line treatment of postmenopausal women
with hormone-receptor positive locally advanced or metastatic
breast cancer [7].
It can be speculated that the tested compounds possessing
a dihydroimidazo[2,1-c][1,2,4]triazole scaffold inhibit the
LS180 and SiHa cancer cell lines by possibly interacting
with important metabolic enzymes.
Compound 12 was found to be the most effective in vitro
against human colon adenocarcinoma cell line LS180 in
both examined concentrations. The tested compound demon-
strated antiproliferative properties those suggest its further in-
vestigation as a potential anticancer agent. Further studies are
in progress to define the important mechanisms of action of
the above mentioned compound.
¨
electrophoresis (MGE), was introduced by Ostling and Johan-
son for the direct visualization of DNA damage in individual
mammalian cells. DNA was isolated from cell cultures after
incubation with compound 7 by phenolechloroform method.
DNA damage in tested cancer cell lines after incubation
with imidazotriazole 7 in a concentration of 29.3 mM
(10 mg mLꢁ1) was analysed using the field gel electrophoresis.
This compound was found to be effective in inducing DNA
damage. This led to cutting of the DNA strands in tested
cell lines and formation of small fragments of DNA e two
higher and one lighter in comparison to control DNA mole-
cules (Fig. 8). The effect of the examined imidazotriazole of
the type 7 seemed to be similar to nuclease function. In con-
clusion compound 7 was found to possess the efficiency for
DNA strand breakage of cancer cell lines such as the cytotoxic
antibiotic e bleomycin [44], isolated from Streptomyces verti-
cillus and effective in combination therapies against certain
types of skin cancer, testicular carcinoma and lymphomas.
DNA strand breakage caused by compound 7 can have dra-
matic effects on higher-order chromatin structure because of
GMK
SiHa
60
60
I – concentration of 10 µg mL-1
I – concentration of 10 µg mL-1
I
II
I
II
II – concentration of 50 µg mL-1
II – concentration of 50 µg mL-1
40
20
0
40
20
0
7
12
7
12
Compounds
Compounds
Fig. 3. Cytotoxicity of tested imidazotriazoles 7 and 12 in both examined con-
centrations (10 and 50 mg mLꢁ1) towards African Green Monkey Kidney cell
line (GMK) expressed as growth inhibition (in %).
Fig. 5. Inhibition of in vitro human uterus carcinoma cell line growth (SiHa)
(expressed as growth inhibition percentage) by tested imidazotriazoles 7 and
12 in both examined concentrations (10 and 50 mg mLꢁ1).

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
411
T47D
60
40
20
0
I – concentration of 10 µg mL-1
II – concentration of 50 µg mL-1
I
II
7
12
Compounds
Fig. 6. Inhibition of in vitro human breast carcinoma cell line growth (T47D)
(expressed as growth inhibition in %) by tested imidazotriazoles 7 and 12 in
both examined concentrations (10 and 50 mg mLꢁ1).
its supercoiling and tight packaging within the nucleus. Taking
into account the above mentioned biological activity, com-
pound 7 may be promising for the development of novel
agents that induce the DNA strand breakage.
Photo 1a. Control cell of breast cancer line (T47D) (the comet assay).
compounds 1e3, 5 and 12 were found to be more toxic against
HeLa cancer cell line than towards normal HSF cells. Sub-
stance 6 revealed similar level of susceptibility towards both
HeLa and HSF cells.
The majority of the investigated compounds revealed low
toxicity towards the examined normal cell line e HSF cells.
Only compound 10, having a log kW value of 3.41 in water
system with dioxane, in a concentration of 100 mM caused sig-
nificant decrease (to 16%) in viability of HSF cells.
All the compounds with the best cytotoxicity against leukae-
mic RPMI 8226 cells (8e12) possess the lipophilic weak-elec-
tron-withdrawing chloro substituent and the lipophilic weak
electron-donating methyl group at the 4-position of the phenyl
ring and simultaneously 2-CH3; 4-Cl, 2,4-Cl2 and 4-Cl substit-
uents at the second phenyl ring, that of the phenoxymethylene
moiety. These compounds, with exception of 9 showed
relatively the highest log kW values in the range of 3.41e4.15
(Table 2). Amongst those, the most potent was 11, e.g., 3[(2-
methyl-4-chloro)phenoxymethyl]-7-(4-chlorophenyl)-5H-6,7-
dihydroimidazo[2,1-c][1,2,4]triazole, having a log kW value of
3.87 in aqueous system with dioxane. This compound applied
in a concentration of 1 mM caused the highest viability decrease
(to 46.4%) in human leukaemic RPMI 8226 cells. The presence
of both substituted phenyl rings: first at the C-3 (that of the
phenoxymethylene formation) and second at the N-7 seemed to
be an important factor that influenced the antitumour potency
In the next series of experiments, we have also investigated
the action of the designed imidazo[2,1-c][1,2,4]triazoles (1e3,
5e12) on the viability of human leukaemic RPMI 8226 cells
and HeLa cancer cells in order to select compounds having
promising antiproliferative activities. The complete set of
data obtained in the MTT viability assay revealed that the leu-
kaemia cell line RPMI 8226 was relatively more sensitive to
five of 11 tested compounds (8e12) than was the other human
cervix cancer cell line e HeLa (Table 4). The highest viability
decreases (to 46, 32 and 31%, respectively, after exposure for
24 h) in leukaemic RPMI 8226 cells treated with 1, 50 and
100 mM heterobicycle 11 were observed. Also compound 10
in concentrations of 1, 50 and 100 mM caused significant via-
bility decreases (to 60.1, 34.5 and 34%, respectively), in hu-
man leukaemic RPMI 8226 cells. The remaining compounds
8, 9 and 12 in concentrations of 50 and 100 mM were proved
to evoke viability decreases to 24.4e39.9% in leukaemic
RPMI 8226 cells. On the contrary, about two to three-fold
lower viability decreases were produced in HeLa cancer cells
treated with the same concentrations of these compounds.
However, heterobicycles 1e3, 5e6 in three different concen-
trations of the compound solutions (1, 50, 100 mM) nearly
did not change the viability of human leukaemic RPMI 8226
cells. Simultaneously, slight viability changes seemed to be
mainly concentration-independent (Table 4). Furthermore,
LS 180
SiHa
T47D
GMK
LS 180
SiHa
T47D
PCR
product
125 bp
C
7
C
7
C
7
C
7
7
C
7
C
7
C
C – control
C – control
bp – base pairs
Fig. 8. DNA damage in tested cell lines after incubation with compound 7 in
a concentration of 29.3 mM (10 mg mLꢁ1). Cells, prepared as agarose plugs,
were lysed and subjected to pulsed field gel electrophoresis through a 1% aga-
rose gel.
Fig. 7. SOD gene expression in cancer cell lines after incubation with tested
imidazotriazole 7 in a concentration of 29.3 mM (10 mg mLꢁ1). Electropho-
retogram on 1% agarose gel.

412
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
Table 4
Percentage of viable normal human skin fibroblasts (HSF) and cancer cell
lines (RPMI and HeLa) following 24 h treatment with the tested concentra-
tions of imidazotriazoles 1e3, 5e12
Comp.
Concentration
in mM
Cell viability
in normal
HSF cells
Cell viability
in RPMI
cancer cells
Cell viability
in HeLa
cancer cells
1
1
50
100
1
97.6 ꢂ 2.8
89.5 ꢂ 3.3
85.6 ꢂ 3.2
104.7 ꢂ 4.4
95.2 ꢂ 1.6
89.3 ꢂ 4.9
101.0 ꢂ 4.7
90.9 ꢂ 2.7
90.7 ꢂ 1.9
91.7 ꢂ 3.7
87.6 ꢂ 2.4
83.0 ꢂ 1.7
80.3 ꢂ 1.3
67.1 ꢂ 1.5
64.6 ꢂ 3.0
79.2 ꢂ 5.3
76.8 ꢂ 4.5
72.5 ꢂ 3.7
88.1 ꢂ 4.6
68.4 ꢂ 4.2
64.7 ꢂ 3.7
74.9 ꢂ 5.9
56.9 ꢂ 5.3
62.1 ꢂ 3.8
88.7 ꢂ 2.6
63.8 ꢂ 5.3
16.2 ꢂ 7.2
79.5 ꢂ 4.6
74.0 ꢂ 5.0
71.0 ꢂ 5.1
83.0 ꢂ 4.9
83.9 ꢂ 11.9
86.8 ꢂ 14.2
99.3 ꢂ 4.3
101.6 ꢂ 4.8
97.6 ꢂ 3.8
101.5 ꢂ 6.5
96.5 ꢂ 5.5
91.3 ꢂ 7.5
103.6 ꢂ 7.3
96.9 ꢂ 5.0
87.5 ꢂ 6.1
104.3 ꢂ 5.1
99.0 ꢂ 5.1
100.9 ꢂ 4.0
99.7 ꢂ 5.7
98.4 ꢂ 7.6
94.9 ꢂ 8.5
112.2 ꢂ 4.8
113.9 ꢂ 4.9
108.4 ꢂ 4.3
104.0 ꢂ 2.9
39.5 ꢂ 1.7
39.9 ꢂ 2.2
85.5 ꢂ 3.7
27.7 ꢂ 1.0
25.4 ꢂ 1.5
60.1 ꢂ 3.3
34.5 ꢂ 1.1
34.0 ꢂ 1.0
46.4 ꢂ 2.4
32.4 ꢂ 1.5
31.1 ꢂ 2.0
98.4 ꢂ 5.6
24.4 ꢂ 1.2
24.5 ꢂ 1.7
73.2 ꢂ 4.6
75.4 ꢂ 9.8
72.8 ꢂ 5.7
93.0 ꢂ 12.3
91.7 ꢂ 11.0
80.6 ꢂ 5.3
77.9 ꢂ 7.0
67.6 ꢂ 2.8
68.4 ꢂ 2.7
85.3 ꢂ 7.0
71.1 ꢂ 5.1
70.3 ꢂ 6.1
81.5 ꢂ 7.2
72.1 ꢂ 6.5
68.9 ꢂ 6.0
65.6 ꢂ 8.0
75.1 ꢂ 3.9
75.9 ꢂ 5.2
89.0 ꢂ 6.1
78.3 ꢂ 6.1
77.9 ꢂ 5.2
95.1 ꢂ 4.2
75.2 ꢂ 4.2
75.6 ꢂ 2.2
63.2 ꢂ 2.3
56.3 ꢂ 2.8
52.4 ꢂ 1.3
92.1 ꢂ 4.5
71.8 ꢂ 3.8
71.0 ꢂ 3.7
68.4 ꢂ 7.9
59.9 ꢂ 4.2
56.3 ꢂ 4.9
2
50
100
1
3
50
100
1
5
50
100
1
Photo 1b. DNA molecules damage in breast cancer cells (T47D) after incuba-
tion with compound 7 in a concentration of 10 mg mLꢁ1 (the comet assay).
6
50
100
1
against that human hematopoietic cancer cell line. Thus tested
imidazotriazoles unsubstituted in the 3-position of heterobicycle
(1e3) and those possessing unsubstituted or disubstituted phe-
nyl ring, that of the phenoxymethylene formation, and simulta-
neously having unsubstituted the second phenyl ring (5, 7) were
found to be inactive against leukaemic RPMI 8226 cells. All
these compounds had relatively lower log kW values in the range
of 1.16e2.49 (Table 2). Also derivative 6 from this imidazotria-
zole scaffold, having a log kW value of 1.52, and substituted at
the N-7 by a 4-methoxyphenyl group and containing a chloro
substituent at the 4-position of the second phenyl ring, that of
the phenoxymethylene moiety, did not change the viability of
leukaemic RPMI 8226 cells. The replacement of a 4-chloro
and a 4-methyl group of an aromatic phenyl ring at the 7-posi-
tion of heterobicycle in compounds 11 and 9 by a proton like
in the case of compound 7 resulted in the complete loss of activ-
ity against human leukaemic RPMI 8226 cells.
7
50
100
1
8
50
100
1
9
50
100
1
10
11
12
50
100
1
50
100
1
50
100
HSF e human skin fibroblast cells e primary cell line; RPMI 8226 (ECACC
87012702) e human peripheral blood myeloma; HeLa (ECACC 93021013) e
human Negroid cervix epitheloid carcinoma.
Taking into consideration the influence of the following in-
vestigated compounds (8e9 and 11e12) on human leukaemic
RPMI 8226 cells and normal cell line e human skin fibro-
blasts (HSF), the selective action of the examined derivatives
can be expected. Thus, these ones may be used as a basis
for the design of novel antiproliferative agents.
ampicillin and chloramphenicol, respectively. Moreover, com-
pound 9 was found to inhibit the growth of S. epidermidis in con-
centrations of 281.8 mM (100 mg mLꢁ1
) and 563.6 mM
(200 mg mLꢁ1) in the disc-diffusion assay. Compound 13, i.e.,
3-(2,4-dichlorophenoxymethyl)-7-(3,4-dichlorophenyl)-5H-
6,7-dihydroimidazo[2,1-c][1,2,4]triazole, with the highest lipo-
philicity (log kW ¼ 4.61 in aqueous system with dioxane) was
active against P. aeruginosa ATCC 27853 with MIC results at
36.3 mM. It’s antibacterial potency was superior to that of ampi-
cillin and chloramphenicol as observed in Table 6. This com-
pound was also found to exhibit activity against Pr. vulgaris at
concentrations of 232.5 mM (100 mg mLꢁ1) and 465.0 mM
(200 mg mLꢁ1) and K. pneumoniae, En. aerogenes at concentra-
tion of 465.0 mM (200 mg mLꢁ1) in the disc-diffusion assay.
Although, the structural changes of compounds 9 and 13,
significantly altered the log kW values as observed for 9
(log kW ¼ 1.10) and 13 (log kW ¼ 4.61), however, these ones
showed little effect on the antibacterial activity with MIC
values of 44.0 and 36.3 mM, respectively. Simultaneously,
5.2. Antimicrobial action
Three imidazotriazoles of the type 9, 13, 14 have been eval-
uated for their general pharmacological activities and all these
compounds have been found to possess positive antimicrobial
activity (Tables 5 and 6). Two of three tested compounds (9,
13) were found to have highly significant antibacterial activity
but no antifungal potency. These compounds were also inactive
against moulds. Compound 9, e.g., 3-[(2-methyl-4-chloro)phe-
noxymethyl]-7-(4-methylphenyl)-5H-6,7-dihydroimidazo[2,1-
c][1,2,4]triazole, having a log kW value of 1.10 in aqueous
system with dioxane, showed good activity against S. aureus
ATCC 25923 with a MIC value of 44.0 mM. Its antibacterial
potency was found to be 1.2 to 3.6-fold lower than that of

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
413
log kW ¼ ꢁ0.09) and 3 (R ¼ 4-Cl, R0 ¼ H, log kW ¼ 1.89),
which have different log kW values can be given as example.
Simultaneously, for compound 14 antifungal activity superior
to miconazole was observed. Probably, the significant decrease
in lipophilicity and an increasing percentage of sulfur element
could be a qualitative explanation of changes in antimicrobial
specificity of this compound in relation to 9, 13 as observed
in Tables 4 and 5. It is of interest that the literature search
revealed that some derivatives having the same heterocyclic
Table 5
Antimicrobial activities of three synthesized compounds against the tested bac-
terial and fungal isolates using disc-diffusion method
Microorganism
Compound and inhibition zone (mm)
9
13
14
A
M
I
II
I
II
I
II
Escherichia coli ATCC 25922
Pseudomonas aeruginosa
ATCC 27853
e
e
e
e
e
e
e
e
e
e
þþ
þ
e
e
þ
þþ
Proteus vulgaris
e
e
e
þ
e
þ
e
e
e
þþ
þ
e
e
e
e
e
e
e
e
e
e
e
e
e
skeleton
e
e.g., 7-aryl-5-methyl-3-thiolo-imidazo[2,1-c]
Klebsiella pneumoniae
Enterobacter aerogenes
Staphylococcus aureus
ATCC 25923
e
e
[1,2,4]triazol-6-ones have been reported as possible antifungal
drugs [15].
e
þþ
þ
e
þþ
e
As a result, compound 9 was found to exhibit the most po-
tent in vitro antibacterial activity with a MIC value of 44.0 mM
against S. aureus ATCC 25923 and may be considered prom-
ising for the development of new antibacterial agents.
Compound 13 was found to express the most potent in vitro
anti Gram-negative activity with a MIC value of 36.3 mM
against P. aeruginosa ATCC 27853. This compound was gen-
erally active against the majority of Gram-negative bacterial
strains examined, with the exception of E. coli ATCC 25922,
and therefore may be considered promising for the develop-
ment of selective anti Gram-negative antibacterial agents.
As a result compound 14 demonstrated good antifungal ac-
tivity against C. albicans ATCC 10231 with a MIC value of
30.9 mM. This compound showed superior antifungal activity
to miconazole. Taking into account its antifungal effectiveness
and lack of activity against all the examined Gram-positive
and Gram-negative bacterial strains and moulds, this com-
pound may be considered promising for the development of
new antifungal agents.
Staphylococcus epidermidis
Streptococcus pyogenes
Streptococcus agalactiae
þ
e
e
þþ
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
e
þ
e
þþ
þþ
e
e
e
Candida albicans ATCC 10231 e
Aspergillus spp.
e
þþ þþ
þþ
e
e
e
e
e
e
Results were interpreted in terms of the diameter of the inhibition zone: (e):
0e10 mm (R, resistant); (þ): 11e16 mm (I, intermediate); (þþ): 17e
25 mm (S, susceptible); I e concentration of 100 mg mLꢁ1, which correspond
to concentration range of 232.5e395.7 mM depending on molecular weight of
the examined compound; II e concentration of 200 mg mLꢁ1, which corre-
spond to concentration range of 465.0e791.3 mM depending on molecular
weight of the examined compound; Standards: A e ampicillin in concentration
of 572.4 mM (200 mg mLꢁ1); M e miconazole in concentration of 480.6 mM
(200 mg mLꢁ1).
higher lipophilicity of 13 could possible be a qualitative expla-
nation of changes in the antibacterial specificity of this com-
pound in relation to 9 as observed in Tables 5 and 6.
Heterobicycle 14, i.e., 7-(4-chlorophenyl)-5H-6,7-dihydroi-
midazo[2,1-c][1,2,4]triazole-3-thiol, having the lowest value
of log kW (ꢁ0.09), revealed highly significant antifungal activ-
ity and was found to be completely inactive against all the ex-
amined bacterial and mould strains in the disc-diffusion
method (Table 5). Full details of the method of testing have
been described elsewhere [45]. In the present study in the mi-
crodilution assay imidazotriazole of the type 14 demonstrated
good antifungal activity against C. albicans ATCC 10231 with
a MIC value of 30.9 mM. Its antifungal potency was 1.2-fold
higher than that of miconazole. An introduction of the sulfanyl
group in the position 3 to the dihydroimidazotriazole system
as in 14 significantly altered the log kW value in aqueous sys-
tem with dioxane. Imidazotriazoles 14 (R ¼ 4-Cl, R0 ¼ SH,
6. Conclusion
In this report, an easy and useful method to synthesize anti-
tumour and antimicrobial active imidazotriazole aryl deriva-
tives containing the phenoxymethylene (7e9, 11e13)
formation or the sulfanyl group (14) has been presented. The
identified analogues, in particular 3-phenoxymethyl-7-aryl-
5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole derivatives (7
and 12), demonstrated antiproliferative and apoptotic proper-
ties justifying their further investigation as potential anticancer
agents. Moreover, compound 7 was found to exhibit efficiency
for DNA strand breakage and may be promising for the devel-
opment of novel antitumour agents that induce the DNA strand
breakage. Also significant viability decreases in human leu-
kaemic RPMI 8226 cells treated with different concentrations
of compounds 8e12 were observed, suggesting their antipro-
liferative properties. Compounds 9, 13 can serve as novel tem-
plates for bacterial infection chemotherapy, whereas 14 may
be potential candidate for new antifungal agents. Further opti-
mization of these identified chemical leads can possibly lead
to more active molecules. Since all the examined compounds
(7e14) are showing promising results, studies to establish
their in vivo efficacy and safety are being planned for their
further development. It may be concluded that the fusion of
4,5-dihydroimidazole and [1,2,4]triazole nuclei in the case
Table 6
Antimicrobial activity expressed as MIC (mM) of the tested imidazotriazoles 9,
13, 14
Microorganism code
Compound
Standard
A
9
13
14
C
M
Staphylococcus aureus
ATCC 25923
44.0
35.8
12.1
Pseudomonas aeruginosa
ATCC 27853
36.3
>357.7 >386.8
Candida albicans
ATCC 10231
30.9
37.5
Standards: A e ampicillin; C e chloramphenicol; M e miconazole.

414
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
of the examined bicycles (7e14) might result in bioactive
molecules of high potency, particularly if the substituents are
designed with optimum toxophoric requirements.
CH2), 4.54 (dd, J ¼ 6.8 Hz, J0 ¼ 5.8 Hz, 2H, CH2), 6.97e7.59
(m, 5H, ar-H), 8.19 (s, 1H, CH); 13C NMR (DMSO-d6): 39.7
(imidazolidine-C-5), 52.9 (imidazolidine-C-6), 140.2 (tria-
zole-C-3), 159.0 (C-7a), ar C: 114.1, 120.0, 128.6, 136.0;
EIMS [70 eV, m/z (%)]: 187 (19.6), 186 (Mþ, 100.0), 184
(82.0), 171 (3.3), 170 (2.5), 160 (10.1), 159 (15.5), 158
(37.6), 157 (2.1), 144 (1.5), 143 (2.2), 132 (4.3), 131 (13.5),
130 (13.8), 129 (2.7), 119 (1.6), 118 (10.8), 117 (31.9), 116
(5.9), 109 (7.0), 106 (1.5), 105 (9.2), 104 (38.9), 102 (57.4),
95 (1.9), 93 (4.8), 92 (2.3), 91 (11.8), 90 (4.3), 89 (1.5), 84
(4.0), 83 (14.8), 82 (2.4), 79 (1.8), 78 (6.9), 77 (53.7), 76
(37.2), 75 (8.0), 74 (4.6), 70 (1.4), 65 (4.0), 64 (3.2), 63
(4.6), 56 (3.2), 55 (7.1), 54 (3.1), 53 (2.3), 52 (4.1), 51
(13.4), 49 (6.7).
7. Experimental protocols
7.1. Instrumentations and general materials
Chemicals (methyl iodide, hydrazine hydrate, triethyl or-
thoformate, phenoxyacetic acid derivatives and carbon disul-
fide) were purchased from Merck (Darmstadt, Germany) as
‘synthesis grade’ and used without further purification. Melt-
ing points (m.p.) were determined on a Boetius apparatus
and are given uncorrected. The IR spectra were measured as
potassium bromide pellets using a Perkin-Elmer 1725X spec-
trometer. NMR spectra (1H and 13C) of the compounds synthe-
sized were recorded on a Bruker 300 MHz spectrometer in
hexadeuterodimethyl sulfoxide (DMSO-d6) with TMS as an
external standard at 295 K. Mass spectroscopic analyses for
compounds 1e5, 8e12 were recorded at 70 eV on a Trace
DSQ mass spectrometer (Thermo Finnigan) for molecular
ion peaks. The molecular ion for the compounds 3, 4, 8e12
was calculated according to 35Cl isotope. Thin-layer chroma-
tography was carried out on commercial Merck SiO2 60 F254
plates having fluorescence indicator; the spots were visualized
with UV light l ¼ 254 nm, and by spraying with a 2% ethanol
solution of ninhydrin or charging reagent.
In the high performance liquid chromatographic (HPLC) se-
ries of experiments, fourteen derivatives of the type 1e14 were
chromatographed on octadecyl silica adsorbent (SUPELCO-
SILÔ LC-18) using various aqueous systems: mixture of water
and organic modifiers (methanol e MeOH, acetonitrile e
MeCN or dioxane e DX). Diethylamine (DEA) and phosphate
buffer (pH ¼ 3.5) were added to mobile phase (eluent contain-
ing 0.05 M Lꢁ1 DEA in organic modifier (MeOH, MeCN or
DX) e buffered mobile phase).
7.1.1.2. 7-(4-Methoxyphenyl)-5H-6,7-dihydroimidazo[2,1-c]
[1,2,4]triazole (2). Recrystallized from MeOHeDMF mix-
ture, yield 60.3%, m.p. 265e267 ꢀC; IR (KBr) (n, cmꢁ1):
1
1610 (C]N); H NMR (DMSO-d6, 300 MHz): 3.73 (s, 3H,
OCH3), 4.25 (dd, J ¼ 6.8 Hz, J0 ¼ 5.7 Hz, 2H, CH2), 4.52
(dd, J ¼ 6.8 Hz, J0 ¼ 5.7 Hz, 2H, CH2), 6.99 (d, 2H, ar-H),
7.42 (d, 2H, ar-H), 8.15 (s, 1H, CH); 13C NMR (DMSO-d6):
39.7 (imidazolidine-C-5), 53.4 (imidazolidine-C-6), 55.1
(CH3O), 135.9 (triazole-C-3), 159.3 (C-7a), ar C: 114.3,
115.3, 134.1, 153.4; EIMS [70 eV, m/z (%)]: 217 (18.0), 216
(Mþ, 100.0), 215 (19.1), 202 (7.9), 201 (64.2), 189 (2.6),
188 (16.9), 175 (3.0), 174 (6.1), 173 (31.1), 161 (2.8), 158
(2.3), 147 (7.1), 146 (5.4), 145 (4.3), 134 (8.5), 133 (13.1),
132 (6.1), 121 (6.0), 120 (10.0), 119 (5.2), 118 (7.5), 117
(3.6), 109 (2.2), 108 (6.9), 107 (8.0), 106 (3.3), 105 (4.7),
104 (7.0), 103 (13.5), 102 (3.9), 95 (5.8), 92 (8.8), 91 (4.6),
90 (16.0), 83 (2.8), 80 (2.5), 79 (3.3), 78 (5.8), 77 (11.0), 76
(5.6), 75 (3.2), 66 (3.2), 65 (5.3), 64 (7.8), 63 (8.3), 55
(2.6), 53 (2.3), 52 (2.4), 51 (2.9).
7.1.1.3. 7-(4-Chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,
2,4]triazole (3). Recrystallized from MeOHeDMF mixture,
yield 74.4%, m.p. 242e244 ꢀC; IR (KBr) (n, cmꢁ1): 1611
(C]N); 1H NMR (DMSO-d6, 300 MHz): 4.29 (dd,
J ¼ 6.5 Hz, J0 ¼ 5.8 Hz, 2H, CH2), 4.52 (dd, J ¼ 6.5 Hz,
J0 ¼ 5.7 Hz, 2H, CH2), 7.41 (d, 2H, ar-H), 7.53 (d, 2H, ar-
H), 8.21 (s, 1H, CH); 13C NMR (DMSO-d6): 39.7 (imidazoli-
dine-C-5), 53.1 (imidazolidine-C-6), 139.1 (triazole-C-3),
158.8 (C-7a), ar C: 115.7, 123.9, 128.5, 136.2; EIMS [70 eV,
m/z (%)]: 223 (3.8), 222 (31.8), 221 (23.3), 220 (Mþ,
100.0), 219 (35.9), 207 (1.2), 205 (1.4), 204 (1.3), 196 (3.1),
195 (3.9), 194 (18.2), 193 (9.3), 192 (26.5), 191 (1.1), 185
(4.3), 184 (5.0), 167 (2.3), 166 (3.3), 165 (5.0), 164 (5.1),
159 (1.2), 158 (5.5), 157 (8.8), 156 (2.5), 154 (1.7), 153
(5.6), 152 (5.0), 151 (15.2), 141 (2.0), 140 (8.3), 139 (14.8),
138 (23.0), 137 (32.5), 136 (1.2), 131 (3.6), 130 (3.6), 129
(1.5), 128 (1.0), 127 (2.3), 126 (1.1), 125 (6.6), 124 (1.6),
117 (3.4), 116 (2.4), 113 (6.6), 112 (2.3), 111 (20.2), 110
(2.4), 109 (3.8), 104 (1.4), 103 (4.4), 102 (25.6), 101 (2.4),
100 (1.9), 99 (2.7), 95 (2.6), 92 (2.8), 91 (1.9), 90 (2.7), 89
(2.6), 85 (2.1), 84 (4.2), 83 (13.7), 82 (1.1), 78 (1.4), 77
(4.9), 76 (8.4), 75 (24.7), 74 (6.0), 73 (2.9), 70 (1.5), 65
Elemental analyses were performed on a Perkin-Elmer an-
alyzer and were in the range of ꢂ0.4% for each element ana-
lyzed (C, H, N, Cl).
7.1.1. General procedure for synthesis of 7-aryl-5H-6,7-
dihydroimidazo[2,1-c][1,2,4]triazoles (1e4)
A mixture containing 1-aryl-2-hydrazonoimidazolidine
(0.03 mol) and triethyl orthoformate (0.03 mol) in 100 mL of
DMF was heated under reflux for 6 h. The amount of the col-
lected EtOH was a measure of the reaction course. Then the
reaction mixture was concentrated to ca. 30 mL and cooled
overnight. The precipitate yielded was filtered off, washed
three times with cold methanol. After collection and purifica-
tion by recrystallization from MeOHeDMF mixture or from
DMF, the compounds 1e4 were obtained in 60.3e74.4%
yields.
7.1.1.1. 7-Phenyl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
(1). Recrystallized from MeOHeDMF mixture, yield 68.3%,
m.p. 238e241 ꢀC; IR (KBr) (n, cmꢁ1): 1608 (C]N); 1H NMR
(DMSO-d6, 300 MHz): 4.35 (dd, J ¼ 6.7 Hz, J0 ¼ 5.8 Hz, 2H,

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
415
(1.1), 64 (2.2), 63 (5.2), 62 (2.5), 61 (1.5), 56 (5.1), 55 (9.4),
54 (3.1), 53 (2.3), 52 (2.6), 51 (9.7), 50 (11.7), 49 (1.0), 43
(1.1), 42 (1.7), 41 (1.9), 40 (1.3), 39 (3.6), 38 (2.8), 37 (2.1).
OCH2), 7.10e7.40 (m, 8H, ar-H); 13C NMR (DMSO-d6):
39.8 (imidazolidine-C-5), 53.5 (imidazolidine-C-6), 55.2
(CH3O), 60.8 (CH2O), 136.1 (triazole-C-3), 156.4 (C-7a), ar
C: 114.1, 115.8, 128.5, 130.6, 136.5, 143.7, 157.2, 157.8.
7.1.1.4. 7-(3,4-Dichlorophenyl)-5H-6,7-dihydroimidazo[2,1-c]
[1,2,4]triazole (4). Recrystallized from DMF, yield 65.5%,
m.p. 199e202 ꢀC; IR (KBr) (n, cmꢁ1): 1609 (C]N); 1H
NMR (DMSO-d6, 300 MHz): 4.29 (dd, J ¼ 7.4 Hz,
J0 ¼ 6.2 Hz, 2H, CH2), 4.55 (dd, J ¼ 7.5 Hz, J0 ¼ 6.3 Hz, 2H,
CH2), 7.18e7.95 (m, 3H, ar-H), 8.16 (1H, CH); 13C NMR
(DMSO-d6): 39.7 (imidazolidine-C-5), 53.2 (imidazolidine-
C-6), 140.0 (triazole-C-3), 158.4 (C-7a), ar C: 114.3, 115.6,
121.6, 130.4, 131.3, 136.4; EIMS [70 eV, m/z (%)]: 258
(10.6), 257 (13.0), 256 (64.0), 255 (44.3), 254 (Mþ, 100.0),
253 (57.0), 230 (8.3), 229 (5.9), 228 (23.8), 227 (8.8), 226
(25.0), 219 (6.5), 218 (7.0), 200 (4.2), 198 (4.8), 192 (8.5),
191 (8.0), 187 (9.3), 186 (5.1), 185 (13.8), 175 (5.5), 174
(11.8), 173 (21.2), 172 (18.1), 171 (31.4), 159 (4.4), 147
(10.3), 145 (16.9), 138 (6.4), 137 (4.0), 136 (15.8), 135 (4.0),
111 (10.3), 110 (11.0), 109 (34.2), 101 (4.4), 100 (21.0), 99
(5.8), 97 (4.9), 96 (4.2), 95 (5.9), 85 (4.6), 84 (8.0), 83
(16.0), 76 (4.1), 75 (13.5), 74 (13.2), 73 (7.2), 66 (4.4), 55 (9.1).
7.1.2.3. 3-[(2-Methyl-4-chloro)phenoxymethyl]-7-phenyl-5H-6,
7-dihydroimidazo[2,1-c][1,2,4]triazole
(7). Recrystallized
from DMF, yield 44.2%, m.p. 248e251 ꢀC; IR (KBr) (n,
1
cmꢁ1): 1612 (C]N); H NMR (DMSO-d6, 300 MHz): 2.27
(s, 3H, CH3), 4.25e4.55 (m, 4H, 2CH2), 5.20 (s, 2H,
OCH2), 7.08e7.55 (m, 8H, ar-H); 13C NMR (DMSO-d6):
15.4 (CH3), 39.9 (imidazolidine-C-5), 53.4 (imidazolidine-C-
6), 60.9 (CH2O), 138.4 (triazole-C-3), 159.6 (C-7a), ar C:
113.6, 114.2, 121.6, 124.6, 125.3, 127.9, 129.8, 142.6, 154.5.
7.1.2.4. 3-(4-Chlorophenoxymethyl)-7-(4-methylphenyl)-5H-6,
7-dihydroimidazo[2,1-c][1,2,4]triazole
(8). Recrystallized
from iPrOH, yield 59.3%, m.p. 273e276 ꢀC; IR (KBr) (n,
1
cmꢁ1): 1607 (C]N); H NMR (DMSO-d6, 300 MHz): 2.30
(s, 3H, CH3), 4.20e4.45 (m, 4H, 2CH2), 5.19 (s, 2H, OCH2),
7.08e7.41 (m, 8H, ar-H); 13C NMR (DMSO-d6): 19.8 (CH3),
39.8 (imidazolidine-C-5), 53.3 (imidazolidine-C-6), 60.8
(CH2O), 137.7 (triazole-C-3), 159.9 (C-7a), ar C: 114.2,
116.6, 125.1, 129.0, 129.1, 129.2, 143.6, 156.3; EIMS
[70 eV, m/z (%)]: 342 (2.8), 341 (2.0), 340 (Mþ, 8.5), 215
(1.4), 214 (17.5), 213 (100.0), 211 (1.8), 185 (5.3), 184 (2.5),
183 (2.0), 171 (5.4), 170 (39.5), 169 (15.0), 158 (4.1), 157
(15.8), 155 (1.1), 153 (2.1), 145 (1.3), 144 (3.5), 143 (4.1),
142 (1.9), 131 (1.3), 130 (1.3), 129 (1.4), 128 (1.5), 127
(3.0), 119 (1.3), 118 (5.1), 117 (17.0), 116 (11.5), 115 (1.6),
111 (2.4), 105 (1.1), 101 (2.5), 99 (7.4), 92 (1.3), 91 (12.0),
90 (6.9), 89 (5.6), 77 (2.1), 75 (2.2), 73 (2.5), 68 (1.0), 67
(1.1), 66 (3.3), 65 (6.4), 64 (2.2), 63 (3.0), 54 (1.2), 41 (1.8).
7.1.2. Generalprocedure for synthesis ofthe 3-phenoxymethyl-
7-aryl-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
derivatives (5e13)
The appropriate derivative of 1-aryl-2-hydrazonoimidazoli-
dine (0.05 mol) and adequate phenoxyacetic acid derivative
(0.055 mol) were refluxed in 80 cm3 of DMF for 6 h. Then
the excess of solvent was distilled under reduced pressure.
The product was obtained by neutralizing the content with
aqueous sodium hydroxide (6%) after adding cold water, and
finally purified by recrystallization from DMF, iPrOH, EtOH
or DMFeMeOH mixture in the proportion indicated.
7.1.2.5. 3-[(2-Methyl-4-chloro)phenoxymethyl]-7-(4-methyl-
phenyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (9). Re-
crystallized from EtOH, yield 43.5%, m.p. 245e248 ꢀC; IR
(KBr) (n, cmꢁ1): 1609 (C]N); 1H NMR (DMSO-d6,
300 MHz): 2.11 (s, 3H, CH3), 2.18 (s, 3H, CH3), 3.77e4.10
(m, 4H, 2CH2), 5.18 (s, 2H, OCH2), 6.92e7.40 (m, 7H, ar-
H); 13C NMR (DMSO-d6): 15.3 (CH3), 19.8 (CH3), 39.8 (imi-
dazolidine-C-5), 53.3 (imidazolidine-C-6), 60.9 (CH2O),
137.6 (triazole-C-3), 160.0 (C-7a), ar C: 113.6, 114.2, 124.6,
126.1, 128.5, 129.1, 129.8, 143.7, 154.4; EIMS [70 eV, m/z
(%)]: 356 (1.5), 355 (1.2), 354 (Mþ, 4.7), 215 (1.5), 214
(18.2), 213 (100.0), 211 (1.7), 186 (0.8), 185 (5.1), 184
(2.3), 183 (1.8), 172 (0.7), 171 (4.7), 170 (36.5), 169 (12.9),
159 (0.9), 158 (3.7), 157 (13.4), 155 (1.1), 145 (1.0), 144
(2.9), 143 (4.2), 142 (2.1), 141 (3.6), 131 (1.1), 130 (0.8),
125 (0.8), 120 (1.0), 119 (1.1), 118 (3.9), 117 (13.1), 116
(8.5), 115 (1.5), 113 (1.2), 107 (0.8), 105 (1.0), 104 (0.7),
92 (1.0), 91 (10.3), 90 (5.9), 89 (5.2), 78 (1.9), 77 (9.3), 68
(0.8), 67 (0.8), 66 (1.6), 65 (4.9), 63 (1.4), 51 (1.4), 41 (1.4).
7.1.2.1. 3-Phenoxymethyl-7-phenyl-5H-6,7-dihydroimidazo[2,
1-c][1,2,4]triazole (5). Recrystallized from DMF, yield
68.2%, m.p. 247e250 ꢀC; IR (KBr) (n, cmꢁ1): 1608
(C]N); 1H NMR (DMSO-d6, 300 MHz): 4.33 (dd,
J ¼ 7.8 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 4.59 (dd, J ¼ 7.7 Hz,
J0 ¼ 6.3 Hz, 2H, CH2), 5.33 (s, 2H, OCH2), 7.08e7.59 (m,
10H, ar-H); EIMS [70 eV, m/z (%)]: 292 (Mþ, 4.5), 187
(11.9), 186 (100.0), 185 (55.7), 171 (1.7), 160 (4.8), 159
(7.4), 158 (15.9), 157 (2.0), 132 (1.9), 131 (6.0), 130 (6.1),
129 (1.8), 118 (5.1), 117 (14.7), 116 (2.6), 109 (4.3), 105
(6.2), 104 (28.0), 103 (41.0), 97 (2.6), 95 (2.6), 93 (3.6), 91
(7.1), 90 (2.1), 84 (3.0), 83 (9.3), 82 (2.3), 81 (1.9), 78
(3.3), 77 (26.1), 76 (15.2), 75 (3.3), 74 (1.9), 73 (1.8), 71
(1.9), 70 (1.7), 69 (3.5), 65 (2.6), 64 (1.9), 63 (2.6), 57
(2.3), 56 (2.0), 55 (5.5), 54 (2.1), 52 (2.5), 51 (8.5), 50
(4.1), 43 (2.2), 41 (2.1), 39 (2.7).
7.1.2.2. 3-(4-Chlorophenoxymethyl)-7-(4-methoxyphenyl)-5H-
6,7-dihydroimidazo[2,1-c][1,2,4]triazole (6). Recrystallized
from DMF, yield 59.2%, m.p. 230e233 ꢀC; IR (KBr) (n,
7.1.2.6. 3-(4-Chlorophenoxymethyl)-7-(4-chlorophenyl)-5H-6,
7-dihydroimidazo[2,1-c][1,2,4]triazole (10). Recrystallized from
DMFeMeOH mixture (2:1), yield 69.7%, m.p. 244e246
1
cmꢁ1): 1610 (C]N); H NMR (DMSO-d6, 300 MHz): 3.80
(s, 3H, OCH3), 4.02e4.40 (m, 4H, 2CH2), 5.20 (s, 2H,

416
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
ꢀC; IR (KBr) (n, cmꢁ1): 1610 (C]N); H NMR (DMSO-d6,
300 MHz): 4.33 (dd, J ¼ 7.8 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 4.59
(dd, J ¼ 7.7 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 5.33 (s, 2H, OCH2),
7.08e7.59 (m, 8H, ar-H); 13C NMR (DMSO-d6): 39.9 (imida-
zolidine-C-5), 53.5 (imidazolidine-C-6), 60.8 (CH2O), 138.9
(triazole-C-3), 159.6 (C-7a), ar C: 115.9, 116.7, 124.1,
125.1, 128.7, 129.1, 144.0, 156.4; EIMS [70 eV, m/z (%)]:
362 (3.6), 361 (1.3), 360 (Mþ, 5.8), 236 (4.0), 235 (30.1),
234 (13.9), 233 (100.0), 198 (1.7), 179 (4.8), 178 (2.1), 177
(16.1), 171 (8.7), 170 (73.9), 169 (30.4), 164 (2.3), 162
(2.4), 155 (2.4), 143 (7.8), 142 (3.0), 141 (1.4), 140 (3.6),
139 (9.1), 138 (4.6), 137 (26.1), 129 (2.1), 128 (2.5), 127
(5.7), 113 (4.4), 111 (14.1), 102 (9.0), 101 (4.1), 100 (1.2),
99 (10.0), 85 (1.4), 77 (1.6), 76 (3.2), 75 (11.2), 74 (1.4), 73
(4.3), 66 (5.2), 65 (1.4), 64 (1.6), 63 (3.7), 54 (2.4), 51
(2.2), 50 (2.2), 42 (3.1), 41 (9.1), 40 (1.3), 39 (2.3).
(1.6), 66 (4.4), 63 (4.6), 62 (1.5), 54 (2.7), 51 (2.2), 50
(2.0), 42 (3.2), 41 (9.4), 39 (1.8).
1
7.1.2.9. 3-(2,4-Dichlorophenoxymethyl)-7-(3,4-dichlorophenyl)-
5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (13). Recrystal-
lized from DMF, yield 44.7%, m.p. 228e230 ꢀC; IR (KBr)
(n, cmꢁ1): 1611 (C]N); 1H NMR (DMSO-d6, 300 MHz):
4.38 (dd, J ¼ 7.5 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 4.65 (dd,
J ¼ 7.6 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 5.35 (s, 2H, OCH2),
7.40e7.65 (m, 6H, ar-H); 13C NMR (DMSO-d6): 39.9 (imida-
zolidine-C-5), 53.1 (imidazolidine-C-6), 61.9 (CH2O), 138.3
(triazole-C-3), 158.8 (C-7a), ar C: 114.6, 117.9, 122.0,
123.7, 126.6, 130.6, 131.1, 132.0, 139.5, 142.5, 146.9, 156.4.
7.1.3. Synthesis of 7-(4-chlorophenyl)-5H-6,7-dihydro-
imidazo[2,1-c][1,2,4]triazole-3-thiol (14)
7.1.2.7. 3[-(2-Methyl-4-chloro)phenoxymethyl]-7-(4-chloroph-
1-(4-Chlorophenyl)-2-hydrazonoimidazolidine (0.01 mol)
was dissolved in 30 mL of methanol. Sodium hydroxide
(0.02 mol) dissolved in small amount of water and 20 mL of
methanol was added. Then carbon disulfide (0.02 mol) in
30 mL of methanol was added dropwise at room temperature.
The reaction mixture was stirred for 30 min at this temperature
and then heated on the water bath as long as hydrogen sulfide
was evolved (about 14 h). The residue was acidified and final
product was obtained. The precipitate was filtered off, washed
two times with water and finally purified by recrystallization
from propan-2-ol.
enyl)-5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole
(11). Re-
crystallized from DMFeMeOH mixture (3:1), yield 66.4%,
m.p. 246e247 ꢀC; IR (KBr) (n, cmꢁ1): 1608 (C]N); 1H
NMR (DMSO-d6, 300 MHz): 2.19 (s, 3H, CH3), 4.31 (dd,
J ¼ 7.5 Hz, J0 ¼ 6.2 Hz, 2H, CH2), 4.57 (dd, J ¼ 7.5 Hz,
J0 ¼ 6.3 Hz, 2H, CH2), 5.20 (s, 2H, OCH2), 7.12e7.55 (m,
7H, ar-H); 13C NMR (DMSO-d6): 15.6 (CH3), 40.0 (imidazo-
lidine-C-5), 53.5 (imidazolidine-C-6), 60.9 (CH2O), 138.9 (tri-
azole-C-3), 159.7 (C-7a), ar C: 113.5, 115.9, 124.1, 124.6,
126.2, 128.5, 128.7, 129.9, 141.1, 154.4; EIMS [70 eV, m/z
(%)]: 376 (3.5), 374 (Mþ, 5.5), 236 (4.8), 235 (30.6), 234
(15.4), 233 (100.0), 231 (1.7), 198 (1.7), 179 (4.4), 178
(1.9), 177 (13.9), 171 (8.7), 170 (72.5), 169 (27.1), 168
(2.0), 164 (1.9), 155 (2.5), 143 (8.7), 142 (3.8), 141 (6.4),
140 (2.9), 139 (9.0), 138 (5.5), 137 (24.4), 125 (2.7), 115
(1.6), 113 (4.7), 112 (1.6), 111 (9.9), 102 (8.7), 97 (2.8), 89
(2.7), 85 (1.6), 78 (3.5), 77 (17.6), 76 (2.9), 75 (7.7),
69 (2.0), 67 (1.9), 66 (9.0), 65 (8.1), 63 (2.8), 54 (4.0),
52 (1.7), 51 (5.4), 50 (2.0), 42 (2.8), 41 (8.3), 40 (4.2), 39
(4.7).
7.1.3.1. 7-(4-Chlorophenyl)-5H-6,7-dihydroimidazo[2,1-c][1,
2,4]triazole-3-thiol (14). Recrystallized from iPrOH, yield
76.1%, m.p. 294e297 ꢀC; IR (KBr) (n, cmꢁ1): 1619 (C¼N);
2560 (SH); 1H NMR (DMSO-d6, 300 MHz): 3.80 (s, 1H,
SH), 4.55 (dd, J ¼ 7.5 Hz, J0 ¼ 6.2 Hz, dd, 2H, CH2), 4.70
(dd, J ¼ 7.5 Hz, J0 ¼ 6.2 Hz, dd, 2H, CH2), 7.27e7.66 (m,
4H, ar-H); 13C NMR (DMSO-d6): 39.5 (imidazolidine-C-5),
53.0 (imidazolidine-C-6), 141.0 (triazole-C-3), 158.6 (C-7a),
ar C: 115.5, 123.7, 128.8, 136.0.
7.1.2.8. 3-(2,4-Dichlorophenoxymethyl)-7-(4-chlorophenyl)-
5H-6,7-dihydroimidazo[2,1-c][1,2,4]triazole (12). Recrystal-
lized from DMFeMeOH mixture (3:1), yield 62.5%, m.p.
7.2. HPLC experimental
1
235e236 ꢀC; IR (KBr) (n, cmꢁ1): 1609 (C]N); H NMR
HPLC analysis was performed using liquid chromatograph
LC-10V ATVP Shimadzu equipped with SUPELCOSILÔ LC-
18 150 ꢃ 4.6 mm column (Supelco, Bellefonte, PA, USA)
dp ¼ 5 mm, UVevis SPD-10AVVP Simadzu detector and
Rheodyne 20 mL injector. Detection was at 254 nm. All chro-
matographic measurements were carried out at 22 ꢂ 1 ꢀC with
eluent flow rate of 1.0 mL minꢁ1. Acetonitrile, methanol and
dioxane of chromatographic quality, diethylamine were from
Merck (Darmstadt, Germany). The pH of phosphate buffer
used in experiments in 0.01 M Lꢁ1 concentrations were mea-
sured in aqueous solutions. Chromatograms were registered
for using the program Shimadzu CLASS-VP.
(DMSO-d6, 300 MHz): 4.35 (dd, J ¼ 7.5 Hz, J0 ¼ 6.3 Hz,
2H, CH2), 4.60 (dd, J ¼ 7.6 Hz, J0 ¼ 6.3 Hz, 2H, CH2), 5.33
(s, 2H, OCH2), 7.37e7.60 (m, 7H, ar-H); 13C NMR
(DMSO-d6): 40.1 (imidazolidine-C-5), 53.5 (imidazolidine-
C-6), 61.7 (CH2O), 138.8 (triazole-C-3), 159.8 (C-7a), ar C:
115.9, 122.7, 124.2, 125.4, 128.0, 128.7, 129.3, 143.6,
151.9; EIMS [70 eV, m/z (%)]: 398 (1.5), 396 (4.4), 394
(Mþ, 4.8), 236 (4.6), 235 (34.1), 234 (16.4), 233 (100.0),
198 (1.9), 179 (5.0), 178 (2.3), 177 (16.2), 171 (9.1), 170
(70.7), 169 (30.1), 165 (1.7), 164 (3.3), 163 (3.2), 162 (2.3),
161 (4.3), 155 (2.5), 143 (8.0), 142 (2.7), 140 (2.9), 139
(9.4), 138 (7.3), 137 (27.0), 135 (5.1), 133 (8.2), 113 (4.2),
112 (1.8), 111 (13.3), 109 (2.2), 102 (9.4), 99 (1.4), 85
(2.2), 77 (1.8), 76 (3.2), 75 (10.3), 74 (2.1), 73 (3.8), 67
Statistical analyses of the data were carried out with STA-
TISTICA for Windows (Polish version, StatSoft, Inc. (1997),
2300 East 14 th Street, Tulsa, USA).

K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
417
7.3. Biological assays
European Collection of Cell Cultures (ECACC). Normal cell
line e human skin fibroblasts (HSF) were routinely grown
in Dulbecco’s modified Eagle’s medium (DMEM), supple-
mented with 10% FBS, 100 mg mLꢁ1 of streptomycin,
100 U mLꢁ1 of penicillin in plastic tissue culture flasks
(Nunc, Denmark).
Cells were maintained in RPMI 1640 medium, supple-
mented with 10% FBS, 2 mM L-glutamine and 10 mg mLꢁ1
gentamycin and 1 mM Na pyruvate. Cells were grown at
37 ꢀC in a humidified atmosphere consisting of 5% CO2.
These ones were passaged three times weakly and maintained
at a density of 6 ꢃ 105 (leukaemia RPMI 8226), 3 ꢃ 105
(HeLa) and 1 ꢃ 105 cells (HSF) per mL. Cells used in the ex-
periment were in logarithmic growth phase. The medium used
for experiment had the same constituents as that used for cell
passage, unless otherwise indicated.
7.3.1. Inhibition of tumour cell growth assay
Compounds 7, 12 were selected for screening towards in vi-
tro three human cancer cell lines: human Caucasian colon ad-
enocarcinoma (LS180), human uterus cancer (SiHa), human
breast carcinoma (T47D). Besides two normal cell lines: hu-
man skin fibroblasts (HSF) and Vero (Green Monkey Kidney
cells) were also included in the cytotoxicity study.
In the current protocol each cell line was inoculated at
104 cells per mL density and preincubated on a microtiter
plate. Test agents were then added at double examined concen-
trations (10 and 50 mg mLꢁ1) and culture incubated for 72 h.
End-point determinations were made with 5-bromo-20-de-
oxy-uridine (BrdU) [46e49] labeling on Elisa reader (BIO-
TEC Instruments USA).
The growth percentage was evaluated spectrophotometri-
cally versus untreated controls with used cell viability of
growth assay. Results for each spectrophotometrical measure
were noticed as percent of growth inhibition (Table 2). All ex-
periments were done in triplicates. The investigations were
carried out in the Department of Biology and Genetics, Med-
ical University, Lublin, Poland.
MTT reduction cell viability assay was performed using
cells cultured in 96-well plates. Compounds 1e3, 5e12 were
dissolved in DMSO prior to dilution into the biological assay.
The effect of the examined concentrations (1, 50 and
100 mM) of heterocycles 1e3, 5e12 on the cell viability was
estimated by a colorimetric assay MTT based (the succinate
dehydrogenase inhibition, SDI test) described by Takenouchi
and Munekata [54]. The metabolic activity was measured in
cell populations via incubation with a 3-(4,5-dimethylthiazol-
2-yl)-2,5-diphenyltetrazolium bromide (MTT) that was re-
duced into a coloured, water-insoluble formazan salt by viable
cells. Additions were made to the culture medium for 24 h.
Cells were washed two times with HEPES-buffered incubation
medium (140 mM NaCl, 5 mM KCl, 5 mM NaHCO3, 1.1 mM
MgCl2, 1.2 mM CaCl2, 5.5 mM glucose and 20 mM HEPES,
pH 7.4), and incubated for 45 min at 37 ꢀC in HBM containing
MTT (0.5 mg mLꢁ1). After this period, the HBM was carefully
removed and the blue formazan product was solubilized in
300 mL of 100% DMSO. The absorbance of each well was
read in an ELISA microplate reader at 570 nm. The obtained
results were presented as percentage of cell viability in com-
parison to control. The presented results were obtained from
three independent measurements. The investigations were car-
ried out in the Department of Virology and Immunology, Maria
Curie-Sk1odowska University, Lublin, Poland.
7.3.2. Detection of induction DNA damage in the tested cell
lines after incubation with imidazotriazole 7
Following treatment of heterocycle 7 with 29.3 mM, cells
were washed two times with phosphate buffered saline
(PBS). In the next step the DNA was isolated by using the lys-
ing buffer and proteolytic enzyme e proteinase K [50]. After
purification, DNA samples were spread over 1% agarose gel
with addition of propidium iodide. Electrophoresis was per-
formed at 120 V for 1.5 h at the room temperature. All exper-
iments were repeated three times. The investigations were
carried out in the Department of Biology and Genetics, Med-
ical University, Lublin, Poland.
7.3.3. Evaluation of DNA damage
The evaluation of DNA damage was determined by using
the comet assay [51]. DNA damage was quantified as an in-
crease in tail moment, an indicator of damage that is propor-
tional to the number of strand breaks per cell. Tail moment
is the product of the percent of fluorescence in the tail and
the distance between the means of the head and tail fluores-
cence distributions. All experiments were done in triplicates.
The investigations were carried out in the Department of Biol-
ogy and Genetics, Medical University, Lublin, Poland.
7.3.5. Antimicrobial activity studies
7.3.5.1. Disc-diffusion assay. Assay of antimicrobial activity in
vitro: the synthesized compounds (9, 13, 14) were tested for
their antimicrobial (antibacterial and antifungal) activities by
disc-diffusion method by Kirby-Bauer, using Mueller-Hinton
medium for bacteria and the same medium with 4% glucose
for fungi. The majority of test microorganisms were obtained
from clinical specimens of the Laboratory of Medical Micro-
biology Department, Medical University of Lublin. The
assayed collection included the following microorganisms:
S. epidermidis, S. pyogenes, S. agalactiae (Gram-positive bac-
teria), Pr. vulgaris, K. pneumoniae, En. aerogenes (Gram-neg-
ative bacteria), and Aspergillus spp. Moreover, two reference
strains of bacteria e S. aureus ATCC 25923, P. aeruginosa
7.3.4. Action of novel imidazotriazoles (1e3, 5e12) on the
viability of RPMI 8226 and HeLa cancer cells
Human peripheral blood myeloma e RPMI 8226 (ECACC
87012702) derived from the peripheral blood of a 61-year-old
male with multiple myeloma, is a recognized model for mul-
tiple myelomas [52,53]. Human Negroid cervix epitheloid car-
cinoma e HeLa (ECACC 93021013) is derived from
a cervical carcinoma from a 31-year-old Negro. Both the
above mentioned cancer cells were obtained from the

418
K. Sztanke et al. / European Journal of Medicinal Chemistry 43 (2008) 404e419
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microorganism cultures were spread over the following appro-
priate media: Mueller-Hinton agar for S. aureus ATCC 25923,
E. coli ATCC 25922 and Sabouraud agar for the yeast-like
fungi (C. albicans) and for the moulds (Aspergillus spp.) in
Petri dishes. Then, the paper discs impregnated with the solu-
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the media inoculated with the microorganism. The plates
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