Synthesis and affinity to DNA of phenylbenzoimidazoles and benzoimidazo[1,2-c]quinazolines

Article abstract of DOI:10.1016/j.ejmech.2009.03.004

Novel N-(benzoimidazophenyl)dialkylaminoalkylamides and 6-dialkylaminoalkylbenzoimidazo[1,2-c]quinazolines were prepared as potential interferon inducers and antiviral agents. They were screened for the DNA affinity by the ethidium bromide displacement assay. It was shown that the lg K_a values of the compounds containing tetracyclic benzoimidazo[1,2-c]quinazoline fragment are approximately one order magnitude greater than those of the corresponding acyclic phenylbenzoimidazole derivatives.

Full text of DOI:10.1016/j.ejmech.2009.03.004

European Journal of Medicinal Chemistry 44 (2009) 3305–3312
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Short communication
Synthesis and affinity to DNA of phenylbenzoimidazoles and
benzoimidazo[1,2-c]quinazolines
Elena A. Lyakhova a, Yulia A. Gusyeva b, Julia V. Nekhoroshkova c, Lev M. Shafran c,
,d,
Sergey A. Lyakhov a
*
a A.V. Bogatsky Physico-Chemical Institute of NAS of Ukraine, Lyustdorfskaya Doroga 86, Odessa 65080, Ukraine
b National Polytechnic University of Odessa, 1 Shevchenko Avenue, Odessa 65044, Ukraine
c Ukrainian Scientific and Research Institute of Medicine on Transport, 92 Kanatnaya Street, Odessa 65039, Ukraine
d Odessa National I.I. Mechnikov University, 2 Dvoryanskaya Street, Odessa 65026, Ukraine
a r t i c l e i n f o
a b s t r a c t
Article history:
Novel N-(benzoimidazophenyl)dialkylaminoalkylamides and 6-dialkylaminoalkylbenzoimidazo[1,2-
c]quinazolines were prepared as potential interferon inducers and antiviral agents. They were screened
for the DNA affinity by the ethidium bromide displacement assay. It was shown that the lg Ka values
of the compounds containing tetracyclic benzoimidazo[1,2-c]quinazoline fragment are approximately
one order magnitude greater than those of the corresponding acyclic phenylbenzoimidazole derivatives.
Ó 2009 Elsevier Masson SAS. All rights reserved.
Received 7 August 2008
Received in revised form
2 March 2009
Accepted 6 March 2009
Available online 21 March 2009
Keywords:
Benzoimidazo[1,2-c]quinazoline
Phenylbenzoimidazole
DNA interaction
1. Introduction
The natural factor providing nonspecific antiviral protection is
the interferon system. It is well known [3,4] that interferons are
The fast spread of viral diseases and the ability of viruses to
mutate into new dangerous forms are common obstacles in the
search of reliable antiviral agents. For instance, the epidemic of
severe acute respiratory syndrome (SARS), that took place 11.2002–
07.2003 affected 8447 people, according to the WHO [1], resulting
in 811 (9.6%) decease. The vaccine against coronavirus SARS was
only found after the end of epidemic. Furthermore, application of
chemotherapeutic agents, in particular, of ribavirin, is not usually
effective in the regular therapeutic regimen, while an increase of its
dose causes some serious side effects [2].
The need for the development of highly effective antiviral agents
with a nonspecific protection is obvious. Such agents could provide
a successful prophylaxis and therapy for viral diseases without
preliminary identification of an infectious agent. In addition,
nonspecific agents would eliminate the long procedure required for
the creation and approval of a vaccine.
effectively used for the treatment of viral, bacterial and oncological
diseases. However, application of exogenous interferon has
a number of limitations such as allergic reactions, formation of anti-
interferonic antibodies after prolonged application [5,6], and the
manifestation of side effects at overdose [7,8].
An alternative approach is to induce the synthesis of endoge-
nous interferon. Several interferon inducers such as amizon [9],
arbidol [10,11], primavir (cycloferon) [12,13] and amixine (tilorone)
[14,15] were successfully introduced into clinical practice in
Ukraine. Among these, tilorone showed a high preventive and
therapeutic efficacy for a wide spectrum of infectious agents. It is
known [16] that tilorone is capable of intercalating between the
DNA base pairs with its planar tricyclic fragment [17,18], and it has
been suggested that this intercalation into DNA is the most prob-
able mechanism of interferon induction [19,20]. Significant inter-
feron inducing properties have also been reported for intercalating
derivatives of fluorene [20,21], acridine [22,23], anthraquinone [24]
and phenanthroline [25]. Regarding the above, the search of
interferon inducers among low-molecular weight polycyclic carbo-
and heteroaromatic compounds, capable of forming complexes
with nucleic acids due to intercalation is a perspective direction in
the area of antiviral therapy.
* Corresponding author. Odessa National I.I. Mechnikov University, 2 Dvoryanskaya
Street, Odessa 65026, Ukraine. Tel.: þ380 48 765 51 26; fax: þ380 48 765 96 02.
E-mail address: sergey_a_lyakhov@ukr.net (S.A. Lyakhov).
0223-5234/$ – see front matter Ó 2009 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2009.03.004

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E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
It prompted us to investigate the benzoimidazo[1,2-c]quinazo-
Chloralkylamido derivatives 4 and 5 were obtained by the
reaction of the amine 3 with corresponding chloroacylchlorides in
glacial acetic acid in the presence of sodium acetate at room
temperature for 30–40 min [40] (Scheme 1). Products 4 and 5 were
isolated from the reaction mixture as chromatographically homo-
geneous compounds and then recrystallized from acetone. Treat-
ment of 4 and 5 with the corresponding secondary amines afforded
the compounds 6a–7e (Scheme 1). Unlike the previous step, the
methods of the dialkylaminoalkyl derivatives 6a–7e preparation
were dependent on the number of methylene units in the aliphatic
moiety. Treatment of chloromethyl derivative 4 with a threefold
excess of the secondary amines in DMF at room temperature for
24 h, followed by recrystallization from ethanol provided
compounds 6a–6e (n ¼ 1) in good yield. This method was found
unsuitable for the formation of similar compounds with 7a–7e
(n ¼ 2), and initial alkylating agents were recovered from the
reaction mixture. The synthesis of the dialkylaminoethyl deriva-
tives 7a–7e was accomplished by refluxing of compound 5 with
lines 1 which have been previously shown, via 1H NMR spectros-
copy, to form intercalation complexes with DNA [26]. Nevertheless,
quantitative characteristics of these compounds, in particular, the
constants of association, were not published. Furthermore, the
benzoimidazo[1,2-c]quinazoline derivatives have a low cytotoxicity
(IC50 ¼ 0.45–19.2
mM [26]) and moderate acute toxicity in vivo
(LD50 ¼ 300–500 mg/kg i.p. [27]).
On the other hand, there has been certain interest in the phe-
nylbenzoimidazole derivatives, since this fragment is similar to that
of the benzoimidazo[1,2-c]quinazolines. It is reported in most cases
that crescent-shaped molecules containing one or several benzoi-
midazole motifs (Hoechst 33258, etc.) are well-known minor
groove binding agents [28–36]. But then it was shown by Denny
et al. [37], the short ‘‘round’’ substituted phenylbenzoimidazole
derivatives 2 (R ¼ CH3, Cl, Ph) are also capable of intercalating into
DNA (lg Ka ¼ 5.04–6.43) as it demonstrated in ethidium bromide
displacement assay studies.
N
H
N
H3C
O
N
N
CH3
N
R
N
R
4
X
N
H
N
R
3
2
1
2
The present work is the first stage of our research aimed the
synthesis, investigation of spectral characteristics, affinity of the N-
a three- to fourfold excess of the secondary amine in ethanol for
1.5–2.0 h, followed by recrystallization from acetonitrile
(Scheme 1).
(benzoimidazophenyl)dialkylaminoalkylamides
and
6-dia-
lkylaminoalkylbenzoimidazo[1,2-c]quinazolines to DNA, and
‘‘structure–affinity’’ relationships of these compounds.
6-Chloroalkylbenzoimidazo[1,2-c]quinazolines 8 and 9 were
obtained by acylation of compound 3 with the chloroacylclorides in
H
N
N
N
N
R
N
R
HN
N
n
R
N
O
R
n
2. Results and discussion
glacial acetic acid at 60 ꢀC (Scheme 2) as described previously [40].
Compound 8 was treated with various secondary amines in DMF at
room temperature for 24 h to give the benzoimidazo[1,2-c]quina-
zolines 10a–10e (Scheme 2). This method failed in case of the
preparation of 11a–11e (n ¼ 2). On the other hand, the attempts to
prepare 11a by refluxing compound 9 with an excess of piperidine
in ethanol resulted in the formation of significant amount of
2.1. Synthesis
Initial 2-(2-aminophenyl)benzoimidazole
according to a literature method [38] in yield comparable to that of
previously described [39].
3 was prepared

E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
3307
N
N
N
N
i
N
ii or iii
N
H
H
H
R
N
HN
H2N
HN
Cl
3
6a - 6e (n=1)
7a - 7e (n=2)
4 (n=1)
5 (n=2)
R
O
n
O
n
Scheme 1. i: Cl(CH2)nCOCl, AcOH, AcONa, r.t.; ii: HNR2, DMF, r.t., 24 h (n ¼ 1); iii: HNR2, EtOH, refl., 2 h (n ¼ 2).
N
N
N
N
N
ii or iii
i
N
N
R
N
N
H
Cl
H2N
n
R
n
3
8 (n=1)
9 (n=2)
10a - 10e (n=1)
11a - 11e (n=2)
Scheme 2. i: Cl(CH2)nCOCl, AcOH, 60 ꢀC; ii: HNR2, DMF, r.t., 24 h (n ¼ 1); iii: HNR2, MeOH, refl. (n ¼ 2).
H C
3
CH
O
N
N CH
3
N
N
N
3
NR2]
N
n ¼ 1
n ¼ 2
n ¼ 1
n ¼ 2
6a
7a
10a
11a
6b
7b
10b
11b
6c
7c
10c
11c
6d
7d
10d
11d
6e
7e
10e
11e
compounds 5 and 7a (by TLC approx. <20% and approx. <60%
respectively), though the desired product 11a was also present in
the reaction mixture. Similar results were observed under trans-
formation of 9 to 11b–11e.
with morpholine gave the product 11d only after refluxing for 7 h, at
which time less than 10% of the parent compound 9 remained
unreacted, as detected by quantitative TLC.
Our attempt to obtain hydrochlorides of compounds 10a–10e
and 11a–11e for testing was unsuccessful due to the appearance of
6a–6e and 7a–7e in the corresponding samples. It was found, that
compounds 10a–11e were not stable as hydrochloride salts, running
hydrolysis in the presence of even traces of water. Furthermore, the
6-dialkylaminoalkylbenzimidazo[1,2-c]quinazolines 10a–11e can
be completely hydrolyzed by 6 M hydrochloric acid to the corre-
It is interesting to note that the previously proposed method [26]
of the synthesis for compounds 11a–11e (Scheme 3) based on the
treatment of compounds 7a–7e with a mixture of pyridine-thionyl
chloride in chloroform did not provide the targets 11a–11e at room
temperature. It was observed that refluxing of the chloride 9 with
a three- to fourfold excess of the appropriate secondary amines in
methanol provided the dialkylaminoethylbenzoimidazo[1,2-c]qui-
nazolines 11a–11e in high yield. The rate of this reaction exhibited
a dependence on the nature of secondary amines. Reaction with
4-methyl-piperidine was completed in 10 min, reaction with
piperidine or with 2-methylpiperidine within 30–40 min and
reaction with 4-methyl-piperazine within 2.5–3 h. The reaction
sponding
2-(2-dialkylaminoalkyamidophenyl)benzoimidazoles
6a–7e at 80 ꢀC for 5 min (Scheme 3).
The use of acetic acid instead of hydrochloric acid allowed us to
prepare the aqueous solution of acetates of 10a–11e with no
detectable hydrolysis to phenylbenzoimidazoles 6a–7e during
10–12 h.
It was found that stability of compounds 10a–11e in water
solution substantially depends on pH. For the solutions of
compounds 10a–11e kept at room temperature and pH ¼ 5.0–5.5,
hydrolysis products 6a–7e appeared within 15–45 min (<3%),
reaching concentrations 25–40% in the following 10–12 h. Aqueous
solutions of 10a–11e were stable at pH ¼ 5.7–7.0 with not more
than 3% of the compound were hydrolyzed during 10–12 h, hence
making them suitable for the DNA-binding assay. Additionally, the
degree of hydrolysis of 10a–11e depends on the character of tertiary
amino group. Thus, the 2-methyl-piperidine derivative 10b, in
N
N
i
N
R
N
N
H
R
N
ii
HN
R
N
n
10a - 10e (n=1)
11a - 11e (n=2)
6a - 6e (n=1)
7a - 7e (n=2)
R
O
n
Scheme 3. i: Pyridine-thionyl, CHCl3, r.t.; ii: 6 M HCl, 80 ꢀC.

3308
E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
Table 1
phenylbenzoimidazoles 6a–6e (n ¼ 1) and 7a–7e (n ¼ 2) indicates
that the difference between lg Ka values within the series of these
The lg Ka values of the synthesized compounds.
compounds is not significant (U ¼ 3, Utab. ¼1, U > Utab.
,
a
¼ 0.01). On
Compound
lgC50
lg Ka
Compound
lgC50
lg Ka
the other hand, the lg Ka values of benzoimidazo[1,2-c]quinazolines
10a–10e (n ¼ 1) are significantly different from 11a–11e (n ¼ 2)
6a
6b
6c
6d
6e
7a
7b
7c
7d
7e
ꢃ2.65
ꢃ2.66
ꢃ2.84
ꢃ2.58
ꢃ2.32
ꢃ2.80
ꢃ2.66
ꢃ2.83
ꢃ2.92
ꢃ2.86
4.75
4.76
4.94
4.68
4.42
4.90
4.76
4.93
5.02
4.96
10a
10b
10c
10d
10e
11a
11b
11c
ꢃ3.84
ꢃ3.65
ꢃ3.83
ꢃ3.44
ꢃ3.72
ꢃ4.03
ꢃ4.17
ꢃ4.23
ꢃ4.12
ꢃ4.18
ꢃ4.20
5.94
5.75
5.93
5.54
5.82
6.13
6.27
6.33
6.22
6.28
6.30
(U ¼ 0, Utab. ¼1, U < Utab.
,
a
¼ 0.01).
The observed lg Ka values for the ligands 6a–11e are specific to
monointercalators 4.42–6.33 (Table 1). Additionally, there is
a significant difference in the values of constants for the phenyl-
benzoimidazoles (lg Ka ¼ 4.42–5.02) and the benzimidazo[1,2-
c]quinazolines (lg Ka ¼ 5.54–6.33).
11d
11e
Amixine (tilorone)
3. Conclusion
a series of compounds 10a–10e (n ¼ 1), is the most stable product in
aqueous acidic medium with stability decreasing in the order
10c > 10a > 10e > 10d. It is necessary to note that the benzoimi-
dazo[1,2-c]quinazoline derivatives 11a–11e (n ¼ 2) are relatively
more stable products in aqueous acids (by TLC < 1%, for 10–12 h).
Therefore, compounds 10a–11e were directly converted to corre-
sponding acetates and 6a–7e to hydrochlorides immediately before
using them in the DNA-binding assay.
Thus, the lgKa values of the compounds 10a–11e containing
tetracyclic benzoimidazo[1,2-c]quinazoline fragment are approx-
imately one order magnitude greater than those of the corre-
sponding acyclic phenylbenzoimidazole derivatives 6a–7e. On the
one hand, these differences are in agreement with the Denny’s
conception about minimal intercalators, based on the terms of
planar area size. According to this conception planar part of
10a–11e is really larger than that of 6a–7e [37]. Though, in case
of planar conformation realization of the 6a–7e, these
compounds have even more number of the ‘‘heavy atoms’’ (C, N,
O) coplanar with benzoimidazole ring than tetracyclic 10a–11e.
On the other hand, possibility of rotation about Ph-BIm single
bond in 2-phenylbenzoimidazole allows realization of a set of
non-planar conformations in non-bound by DNA molecule, and
only planar conformation can be realized in the intercalative
complex. Decreasing of the possible conformations number of 6a–
7e under intercalation has to decrease the enthropic increment in
the total intercalation free energy. The last one also may be regarded
as a reason for the affinity decreasing of 2-phenylbenzoimidazoles
6a–7e comparatively to benzoimidazo-quinazolines 10a–11e.
Further clarification of the observed difference in DNA affinity of
2-phenylbenzoimidazoles and benzoimidazo-quinazolines needs
additional investigations, which are in progress.
2.2. Biology
In this paper we have investigated the affinity of the synthesized
compounds to DNA. As Denny had shown [37], that phenyl-
benzimidazoles 1 are also capable of intercalating into DNA, it is
reasonable to evaluate the binding parameters of not only the
tetracyclic compounds 10a–11e but also their acyclic analogues
6a–7e. The affinity of the synthesized compounds to calf thymus
DNA was determined by ethidium bromide displacement assay [41]
and the results are shown in Table 1.
The association constants of the resulting compounds exhibit
a dependence on both the number of methylene units in the
alkyl spacer as well as the nature of the intercalating fragment
itself.
The compounds can be divided into four groups with inter-
calating ability increasing in the following sequence: 6a–6e
(n ¼ 1) ꢁ 7a–7e (n ¼ 2) ꢂ 10a–10e (n ¼ 1) ꢁ 11a–11e (n ¼ 2) (Fig. 1).
In order to determine whether the lg Ka values of the phenyl-
benzoimidazoles 6a–7e and benzoimidazo[1,2-c]quinazolines
10a–11e belong to the same sample, we have carried out the Mann–
Whitney–Wilcoxon U-test [42,43]. The obtained U value (U ¼ 0,
4. Experimental
4.1. General
TLC: silica gel plates (MERK, UV-254), eluent
A
(CHCl3:(CH3)2CO ¼ 10:1); eluent B (C6H6:(C2H5)3N ¼ 10:1). Mp:
Electrothermal IA9100 digital melting-point apparatus, uncor-
rected. IR spectra were recorded on spectrometer Shimadzu FTIR-
8400 in tablets KBr. Mass spectra (FAB) were written on VG
70-70EQ. Mass spectra (electron stroke) were written on MH-1321.
1H NMR spectra are obtained on Varian VXR-300 at 300 MHz (the
internal standard – TMS). The ethidium bromide displacement
assay was carried out on spectrofluorimeter Solar CM2203.
Utab. ¼16, U ꢂ Utab.) is statistically significant ( ¼ 0.01) and shows
a
that the observed difference among these samples is also signifi-
cant. However, similar application of this rank criterion within
6a – 6e
7a – 7e
10a – 10e
11a – 11e
6.2
5.2
4.2
4.2. 2-(1H-Benzoimidazol-2-yl)-phenylamine (3)
A mixture of anthranilic acid (28.1 g, 0.2 mol) and o-phenyl-
enediamine (21.6 g, 0.2 mol) in 400 ml polyphosphoric acid was
heated at 250 ꢀC for 4 h with stirring. Then the reaction mixture
was cooled up to 100 ꢀC, poured under stirring onto 2000 ml of
cold distilled water and solution was led up to pH ¼ 8–9 by addi-
tion of 50% NaOH solution. The resulting precipitate was filtered
and washed with H2O up to neutral pH. The crude product was
recrystallized from ethanol–water mixture with a small amount of
activated charcoal. A yield: 13.2 g (31%). C13H11N3. M.W. 209.25.
M.p.: 214.5–215.0 ꢀC. (Lit. M.p.: 213–214 ꢀC [38]). Rf ¼ 0.36 (eluent
A); Rf ¼ 0.55 (eluent B), at UV-254 spot fluoresces. Mass spectrum
H3C
N
N
N
CH3
N
O
N
N CH3
Fig. 1. The affinity of the synthesized compounds to CT DNA.

E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
3309
(electron stroke), m/z (%): 209 (100) [M]þ, 182 (12), 118 (7),
104 (17).
233 (6), 112 (100), 98 (28). 1H NMR (DMSO-d6): 1.02 (d, 3H,
–N(CH2CH2)2CHCH3); 1.27–1.37 (n/r m, 2H); 1.41–1.55 (n/r m, 2H);
1.62–1.66 (m, 2H); 2.21–2.30 (m, 1H); 2.36–2.40 (m, 1H); 2.80–2.84
(m, 1H); 2.97 (d, 1H, COCH2N); 3.40 (d, 1H, COCH2N); 7.22–7.30 (m,
3H); 7.44–7.50 (m, 1H); 7.66 (n/r m, 2H); 8.00 (d, 1H); 8.76 (d, 1H);
12.72 (s, 1H); 13.02 (br s, 1H).
4.3. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-chloro-acetamide
(4)
Solution of anhydrous sodium acetate (1 g in 10 ml of glacial
acetic acid) was added at a stretch to the solution of 2-(1H-ben-
zoimidazol-2-yl)-phenylamine 3 (4.2 g, 0.02 mol) in 40 ml glacial
acetic acid at room temperature under intensive stirring, following
by chloracetylchloride (3.2 ml, 4.5 g, 0.04 mol) addition dropwise. A
reaction mixture was stirred at room temperature 40 min and put
in solution of sodium acetate (10 g in 150 ml of distilled water). The
resulting precipitate was filtered and properly washed by distilled
water. The product was recrystallized from acetone or ethanol. A
yield: 4.3 g (75%). C15H12ClN3O. M.W. 285.74. M.p.: 307 ꢀC. Rf ¼ 0.27
(CHCl3). Mass spectrum (FAB), m/z (%): 286 (100) [M þ H]þ. Mass
spectrum (electron stroke), m/z (%): 285 (0.8) [M]þ, 267 (100); 249
(68), 232 (57), 220 (34), 194 (19). 1H NMR (DMSO-d6): 4.51 (s, 2H),
7.30–7.36 (m, 3H), 7.51–7.57 (m, 1H), 7.66–7.67 (n/r m, 2H), 8.13 (d,
1H), 8.64 (d, 1H), 13.56 (br s, 1H).
4.7. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-(4-methyl-
piperidin-1-yl)-acetamide (6c)
This compound was prepared from 4 according to the method
mentioned under the synthesis of 6a, recrystallized from acetoni-
trile in 74% yield. C21H24N4O. M.W. 348.45. M.p.: 191–192 ꢀC.
Rf ¼ 0.19 (eluent A), Rf ¼ 0.50 (eluent B), at UV-254 spot fluoresces.
Mass spectrum (FAB), m/z (%): 349 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 348 (3) [M]þ, 249 (22), 236 (100), 233
(14), 220 (11), 112 (79), 98 (6). 1H NMR (DMSO-d6): 0.83 (d, 3H,
–N(CH2CH2)2CHCH3); 1.27–1.34 (n/r m, 3H); 1.49–1.52 (n/r m, 2H);
2.01–2.08 (m, 2H); 2.82 (d, 2H); 3.17 (s, 2H, COCH2N); 7.23–7.30 (m,
3H); 7.44–7.49 (m, 1H); 7.68 (n/r m, 2H); 7.99 (d, 1H); 8.81 (d, 1H);
12.80 (s, 1H).
4.4. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-chloro-
propionamide (5)
4.8. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-morpholin-4-yl-
acetamide (6d)
This compound was prepared from 3 according to the method
mentioned under the synthesis of 4 in 66% yield. C16H14ClN3O.
M.W. 299.76. M.p.: 210–211 ꢀC (decomp.). Rf ¼ 0.58 (eluent A),
Rf ¼ 0.55 (eluent B), at UV-254 spot fluoresces. Mass spectrum
(FAB), m/z (%): 300 (100) [M þ H]þ. 1H NMR (DMSO-d6): 3.03 (t,
2H); 4.00 (t, 2H); 7.26–7.35 (m, 3H); 7.49–7.54 (n/r t, 1H); 7.60 (n/r
d, 1H); 7.77 (n/r d, 1H); 8.13 (d, 1H); 8.70 (d, 1H); 13.20 (s, 1H); 13.23
(s, 1H).
This compound was prepared from 4 according to the method
mentioned under the synthesis of 6a, recrystallized from the
mixture acetonitrile–water (2:1) in 72% yield. C19H20N4O2. M.W.
336.40. M.p.: 209–210 ꢀC. Rf ¼ 0.26 (eluent A), Rf ¼ 0.42 (eluent B),
at UV-254 spot fluoresces. Mass spectrum (FAB), m/z (%): 337 (100)
[M þ H]þ. Mass spectrum (electron stroke), m/z (%): 334 (3) [M]þ,
236 (100), 233 (4), 100 (28). 1H NMR (DMSO-d6): 2.49 (t, 4H,
N(CH2CH2)2O); 3.23 (s, 2H, COCH2N); 3.68 (t, 4H, N(CH2CH2)2O);
7.22–7.37 (m, 3H); 7.44–7.60 (m, 1H); 7.67–7.80 (n/r m, 2H); 8.00 (d,
1H); 8.80 (d, 1H); 10.64 (s, 1H).
4.5. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-piperidin-1-yl-
acetamide (6a)
4.9. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-(4-methyl-
piperazin-1-yl)-acetamide (6e)
To a solution of 4 (0.57 g, 0.002 mol) in DMF (3 ml) was added
piperidine (0.6 ml, 0.006 mol). The reaction mixture was kept at
room temperature overnight, then poured out in 150 ml of distilled
water and led up to pH ¼ 7 by 10% solution HCl. The resulting
precipitate was filtered, washed with H2O to neutral pH, dried and
recrystallized from isopropanole. A yield: 0.45 g (67%) C20H22N4O.
M.W. 334.42. M.p.: 186–187 ꢀC. Rf ¼ 0.22 (eluent A), Rf ¼ 0.20
(eluent B), at UV-254 spot fluoresces. Mass spectrum (FAB), m/z (%):
335 (100) [M þ H]þ. Mass spectrum (electron stroke), m/z (%): 334
(3) [M]þ, 251 (3), 236 (100), 233 (4), 209 (2), 98 (86). 1H NMR
(CDCl3): 1.41–1.49 (m, 2H, –N(CH2CH2)2CH2); 1.63–1.70 (m, 4H,
–N(CH2CH2)2CH2); 2.52 (t, 4H, –N(CH2CH2)2CH2); 3.22 (s, 2H,
COCH2N); 6.99–7.04 (m, 1H); 7.21–7.32 (m, 3H); 7.59–7.67 (m, 3H);
8.68 (d, 1H); 12.49 (s, 1H). 1H NMR (DMSO-d6): 1.41–1.47 (m, 2H,
–N(CH2CH2)2CH2); 1.61–1.68 (m, 4H, –N(CH2CH2)2CH2); 2.49 (t, 4H,
–N(CH2CH2)2CH2); 3.17 (s, 2H, COCH2N); 7.23–7.31 (m, 3H); 7.45–
7.50 (m, 1H); 7.67 (n/r m, 2H); 8.01 (d, 1H); 8.82 (d, 1H); 12.82
(s, 1H); 12.97 (br s, 1H).
This compound was prepared from 4 according to the method
mentioned under the synthesis of 6a, recrystallized from benzene
in 70% yield. C20H23N5O. M.W. 349.44. M.p.: 199–200 ꢀC. Rf ¼ 0.02
(eluent A), Rf ¼ 0.23 (eluent B), at UV-254 spot fluoresces. Mass
spectrum (FAB), m/z (%): 350 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 349 (2) [M]þ, 306 (2), 293 (1), 279 (3),
266 (1), 249 (6), 236 (100), 220 (2), 210 (6), 113 (100). 1H NMR
(DMSO-d6): 2.13 (s, 3H, –N(CH2CH2)2NCH3); 2.40 (n/r m, 4H,
–N(CH2CH2)2NCH3); 2.50 (n/r m, 4H, –N(CH2CH2)2NCH3); 3.21 (s,
2H, COCH2N); 7.23–7.32 (m, 3H); 7.44–7.50 (m, 1H); 7.73 (n/r m,
2H); 7.99 (d, 1H); 8.79 (d, 1H); 12.82 (s, 1H).
4.10. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-piperidin-1-yl-
propionamide (7a)
Piperidine (0.6 ml, 0.51 g, 0.006 mol) was added to a solution of
5 (0.6 g, 0.002 mol) in ethanol (10 ml). The reaction mixture was
boiled for 2 h, evaporated to 1/3 of volume in vacuum and poured in
distilled water (100 ml). In case precipitate not formes, mixture
have been saturated with NaCl then the resulting precipitate was
filtered, washed with H2O and recrystallized from acetonitrile. A
yield 0.49 g (70%). C21H24N4O. M.W. 348.45. M.p.: 195–196 ꢀC.
Rf ¼ 0.01 (eluent A), Rf ¼ 0.11 (eluent B), at UV-254 spot fluoresces.
Mass spectrum (FAB), m/z (%): 349 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 348 (0.6) [M]þ, 264 (2), 244 (2), 236 (15),
221 (3), 210 (18), 98 (100). 1H NMR (DMSO-d6): 1.27–1.30 (m, 2H,
4.6. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-2-(2-methyl-
piperidin-1-yl)-acetamide (6b)
This compound was prepared from 4 according to the method
mentioned under the synthesis of 6a, recrystallized from EtOH–
H2O (2:1) in 52% yield. C21H24N4O. M.W. 348.45. M.p.: 166–167 ꢀC.
Rf ¼ 0.11 (eluent A), Rf ¼ 0.46 (eluent B), at UV-254 spot fluoresces.
Mass spectrum (FAB), m/z (%): 349 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 348 (3) [M]þ, 251 (6), 249 (3), 236 (77),

3310
E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
–N(CH2CH2)2CH2); 1.33–1.40 (m, 4H, –N(CH2CH2)2CH2); 2.36–2.38
(m, 4H, –N(CH2CH2)2CH2); 2.60–2.64 (m, 2H, COCH2CH2N); 2.69–
2.73 (m, 2H, COCH2CH2N); 7.21–7.31 (m, 3H); 7.44–7.49 (m, 1H);
7.63–7.67 (m, 2H); 8.09 (d, 1H); 8.66 (d, 1H); 13.00 (s, 1H).
(m, 3H); 7.44–7.49 (m, 1H); 7.64–7.67 (m, 2H); 8.09 (d, 1H); 8.66
(d, 1H); 13.00 (s, 1H).
4.15. 6-Chloromethyl-benzo[4,5]imidazo[1,2-c]quinazoline (8)
4.11. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-(2-methyl-
piperidin-1-yl)-propionamide (7b)
To the stirred solution of 3 (7.0 g, 0.035 mol) in 100 ml glacial
acetic acid was added dropwise chloracetylchloride (4.4 ml, 6.2 g,
0.055 mol). Solution was heated up on the water bath (not above
60 ꢀC) for 15 min, cooled and poured out in cool water. The
resulting precipitate was filtered, washed with H2O to neutral pH
and dried. After recrystallization from acetone product was
obtained with yield 6.3 g (68%). C15H10ClN3. M.W. 267.72. M.p.:
237–238 ꢀC. Rf ¼ 0.33 (CHCl3). IR nmax cmꢃ1: 2970–2990; 1595;
1665; 690. Mass spectrum (FAB), m/z (%): 268 (100) [M þ H]þ. Mass
spectrum (electron stroke), m/z (%): 267 (100) [M]þ, 232 (55). 1H
NMR (DMSO-d6): 5.49 (s, 2H); 7.55–7.66 (m, 2H); 7.77–7.83 (m, 1H);
7.87–7.93 (m, 1H); 7.97–8.02 (m, 2H); 8.25 (d, 1H); 8.60 (d, 1H).
This compound was prepared from 5 according to the method
mentioned under the synthesis of 7a, recrystallized from acetoni-
trile in 58% yield. C22H26N4O. M.W. 362.48. M.p.: 176–177 ꢀC.
Rf ¼ 0.05 (eluent A), Rf ¼ 0.12 (eluent B), at UV-254 spot fluoresces.
Mass spectrum (FAB), m/z (%): 363 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 362 (0.4) [M]þ, 347 (6), 263 (21), 244 (16),
236 (74), 219 (10), 209 (25), 112 (100), 84 (84). 1H NMR (DMSO-d6):
1.00 (d, 3H, –N(CH2CH2)2CHCH3); 1.05–1.53 (n/r m, 6H); 2.17–2.26
(m, 1H); 2.30–2.35 (m, 1H); 2.55–2.60 (t, 2H, COCH2CH2N); 2.76–
2.85 (m, 2H, COCH2CH2N), 3.00–3.08 (m, 1H); 7.21–7.31 (m, 3H);
7.44–7.49 (m, 1H); 7.62–7.65 (m, 2H); 8.09 (d, 1H); 8.66 (d, 1H);
13.03 (s, 1H).
4.16. 6-(2-Chloro-ethyl)-benzo[4,5]imidazo[1,2-c]quinazoline (9)
This compound was prepared from 3 according to the method
mentioned under the synthesis of 8 in 97% yield. C16H12ClN3. M.W.
281.75. M.p.: 165–166 ꢀC (decomp.). Rf ¼ 0.69 (eluent A), Rf ¼ 0.80
(eluent B), at UV-254 spot absorbs. Mass spectrum (FAB), m/z (%):
282 (100) [M þ H]þ. 1H NMR (CDCl3): 3.77 (t, 2H); 4.20 (t, 2H); 7.38–
7.42 (m, 1H); 7.47–7.51 (m, 1H); 7.57–7.63 (m, 1H); 7.70–7.74
(m, 1H); 7.80–7.83 (m, 1H); 7.88–7.95 (m, 2H); 8.62 (d, 1H).
4.12. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-(4-methyl-
piperidin-1-yl)-propionamide (7c)
This compound was prepared from 5 according to the method
mentioned under the synthesis of 7a, recrystallized from acetoni-
trile in 71% yield. C22H26N4O. M.W. 362.48. M.p.: 202–204 ꢀC.
Rf ¼ 0.01 (eluent A), Rf ¼ 0.12 (eluent B), at UV-254 spot fluoresces.
Mass spectrum (FAB), m/z (%): 363 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 362 (1.2) [M]þ, 264 (3), 244 (4), 236 (11),
221 (4), 210 (20), 112 (100). 1H NMR (DMSO-d6): 0.74 (d, 3H,
–N(CH2CH2)2CHCH3); 0.90–1.03 (m, 2H); 1.19 n/r m, 1H); 1.41 (d,
2H); 1.85 (t, 2H); 2.59–2.64 (m, 2H, COCH2CH2N); 2.70–2.74 (m, 2H,
COCH2CH2N); 2.84 (n/r d, 2H); 7.20–7.31 (m, 3H); 7.43–7.49 (m,1H);
7.63–7.66 (m, 2H); 8.09 (d, 1H); 8.67 (d, 1H); 13.01 (s, 1H).
4.17. 6-Piperidin-1-ylmethyl-benzo[4,5]imidazo[1,2-c]quinazoline
(10a)
To a suspension of 8 (0.54 g, 0.002 mol) in DMF (10 ml) at room
temperature was added piperidine (0.6 ml, 0.51 g, 0.006 mol), thus
a suspension passed in solution. The reaction mixture was kept at
room temperature for 24 h, then poured in 100 ml of distilled
water. The resulting precipitate was filtered, washed with H2O to
neutral pH and dried in the exsiccator above alkali within the night.
After recrystallization from heptane product was obtained with
yield 0.58 g (61%). C20H20N4. M.W. 316.41. M.p.: 145–146 ꢀC.
Rf ¼ 0.27 (eluent A), Rf ¼ 0.52 (eluent B), at UV-254 spot absorbs.
Mass spectrum (FAB), m/z (%): 317 (100) [M þ H]þ. 1H NMR (DMSO-
d6): 1.43–1.45 (m, 6H); 2.59 (n/r m, 4H); 4.15 (s, 2H, ArCH2N); 7.48–
7.60 (m, 2H); 7.71–7.77 (m, 1H); 7.82–7.88 (m, 1H); 7.93–7.96
(m, 2H); 8.09 (d, 1H); 8.57 (d, 1H).
4.13. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-morpholin-4-yl-
propionamide (7d)
This compound was prepared from 5 according to the method
mentioned under the synthesis of 7a, recrystallized from acetoni-
trile in 76% yield. C20H22N4O2. M.W. 350.42. M.p.: 210–212 ꢀC
(decomp.). Rf ¼ 0.04 (eluent A), Rf ¼ 0.48 (eluent B), at UV-254 spot
fluoresces. Mass spectrum (FAB), m/z (%): 351 (100) [M þ H]þ. Mass
spectrum (electron stroke), m/z (%): 350 (1) [M]þ, 332 (8), 320 (6),
307 (3), 281 (8), 264 (6), 236 (100), 222 (9), 209 (75), 100 (70). 1H
NMR (DMSO-d6): 2.43–2.45 (m, 4H, –N(CH2CH2)2O); 2.64–2.69 (m,
2H, COCH2CH2N); 2.74–2.79 (m, 2H, COCH2CH2N); 3.43 (t, 4H,
–N(CH2CH2)2O); 7.23–7.31 (m, 3H); 7.46–7.51 (m, 1H); 7.61 (n/r m,
1H); 7.72 (n/r m, 1H); 8.10 (d, 1H); 8.66 (d, 1H); 13.00 (s, 1H); 13.14
(br s, 1H).
4.18. 6-(2-Methyl-piperidin-1-ylmethyl)-benzo[4,5]imidazo[1,2-
c]quinazoline (10b)
This compound was prepared from 8 according to the method
mentioned under the synthesis of 10a, recrystallized from heptane
in 62% yield. C21H22N4. M.W. 330.44. M.p.: 134–135 ꢀC. Rf ¼ 0.41
(eluent A), Rf ¼ 0.52 (eluent B), at UV-254 spot absorbs. Mass
spectrum (FAB), m/z (%): 331 (100) [M þ H]þ. 1H NMR (DMSO-d6):
1.20 (d, 3H, –N(CH2CH2)2CHCH3); 1.37 (n/r m, 4H); 1.58 (n/r m, 2H);
2.46–2.56 (m, 1H); 2.65–2.71 (m, 1H); 2.85 (n/r m, 1H); 4.09 (d, 1H,
ArCH2N); 4.54 (d, 1H, ArCH2N); 7.47–7.60 (m, 2H); (m, 1H); 7.81–
7.87 (m, 1H); 7.91–7.95 (m, 2H); 8.32 (d, 1H); 8.57 (d, 1H).
4.14. N-[2-(1H-Benzoimidazol-2-yl)-phenyl]-3-(4-methyl-
piperazin-1-yl)-propionamide (7e)
This compound was prepared from 5 according to the method
mentioned under the synthesis of 7a, recrystallized from acetoni-
trile in 56% yield. C21H25N5O. M.W. 363.47. M.p.: 278–279 ꢀC. Rf ¼ 0
(eluent A), Rf ¼ 0.02 (eluent B), at UV-254 spot fluoresces. Mass
spectrum (FAB), m/z (%): 364 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 363 (3) [M]þ, 320 (6), 307 (10), 293 (31),
275 (11), 264 (18), 244 (7), 236 (51), 222 (27), 210 (47), 113 (71). 1H
NMR (DMSO-d6): 2.04 (s, 3H, –N(CH2CH2)2NCH3); 2.17 (n/r m, 4H,
–N(CH2CH2)2NCH3); 2.43 (n/r m, 4H, –N(CH2CH2)2NCH3); 2.61–2.65
(m, 2H, COCH2CH2N); 2.72–2.76 (m, 2H, COCH2CH2N); 7.21–7.31
4.19. 6-(4-Methyl-piperidin-1-ylmethyl)-benzo[4,5]imidazo[1,2-
c]quinazoline (10c)
This compound was prepared from 8 according to the method
mentioned under the synthesis of 10a, recrystallized from heptane
in 68% yield. C21H22N4. M.W. 330.44. M.p.: 142–144 ꢀC. Rf ¼ 0.52
(eluent A), Rf ¼ 0.52 (eluent B), at UV-254 spot absorbs. Mass

E.A. Lyakhova et al. / European Journal of Medicinal Chemistry 44 (2009) 3305–3312
3311
spectrum (FAB), m/z (%): 331 (100) [M þ H]þ, 259, 233, 219, 112.
4.24. 6-[2-(4-Methyl-piperidin-1-yl)-ethyl]-benzo[4,5]imidazo[1,2-
c]quinazoline (11c)
Mass spectrum (electron stroke), m/z (%): 233 (100), 98 (25). 1H
NMR (DMSO-d6): 0.81 (d, 3H, N(CH2CH2)2CHCH3); 0.98–1.06
(m, 2H); 1.36(n/r m,1H, N(CH2CH2)2CHCH3); 1.56(d, 2H); 2.17 (t, 2H);
2.95 (d, 2H); 4.16 (s, 2H, COCH2N); 7.47–7.58 (m, 2H); 7.70–7.76 (m,
1H); 7.81–7.89 (m, 1H); 7.92–7.95 (m, 2H); 8.07 (d, 1H); 8.57 (d, 1H).
This compound was prepared from 9 according to the method
mentioned under the synthesis of 11a, recrystallized from iso-
propanol in 68% yield. C22H24N4. M.W. 344.46. M.p.: 108–110 ꢀC.
Rf ¼ 0.07 (eluent A), Rf ¼ 0.48 (eluent B), at UV-254 spot absorbs.
Mass spectrum (FAB), m/z (%): 345 [M þ H]þ, 112 (100). Mass
spectrum (electron stroke), m/z (%): 344 (0.5) [M]þ, 244 (9), 112
(100). 1H NMR (DMSO-d6): 0.91 (d, 3H, N(CH2CH2)2CHCH3); 1.16–
1.29 (m, 2H); 1.38 (n/r m, 1H, N(CH2CH2)2CHCH3); 1.62–1.66 (m,
2H); 2.06–2.13 (m, 2H); 3.00–3.04 (m, 4H); 3.60 (t, 2H); 7.45–7.57
(m, 2H); 7.62–7.67 (m, 1H); 7.75–7.80 (m, 1H); 7.83 (d, 1H); 7.91
(d, 1H); 8.16 (d, 1H); 8.53 (d, 1H).
4.20. 6-Morpholin-4-ylmethyl-benzo[4,5]imidazo[1,2-
c]quinazoline (10d)
This compound was prepared from 8 according to the method
mentioned under the synthesis of 10a, recrystallized from heptane
in 82% yield. C19H18N4O. M.W. 318.38. M.p.: 191–192 ꢀC. Rf ¼ 0.38
(eluent A), Rf ¼ 0.40 (eluent B), at UV-254 spot absorbs. IR nmax
cmꢃ1: 2770–2990; 1600, 1665. Mass spectrum (FAB), m/z (%): 319
(100) [M þ H]þ, 233, 100. Mass spectrum (electron stroke), m/z (%):
233 (98), 83 (100). 1H NMR (DMSO-d6): 2.63 (t, 4H, N(CH2CH2)2O);
3.52 (t, 4H, N(CH2CH2)2O); 4.22 (s, 2H, COCH2N); 7.48–7.60 (m, 2H);
7.71–7.76 (m, 1H); 7.81–7.87 (m, 1H); 7.93–7.97 (m, 2H); 8.10
(d, 1H); 8.56 (d, 1H).
4.25. 6-(2-Morpholin-4-yl-ethyl)-benzo[4,5]imidazo[1,2-
c]quinazoline (11d)
This compound was prepared from 9 according to the method
mentioned under the synthesis of 11a, recrystallized from iso-
propanol in 81% yield. C20H20N4O. M.W. 332.41. M.p.: 190–191 ꢀC.
Rf ¼ 0.12 (eluent A), Rf ¼ 0.31 (eluent B), at UV-254 spot absorbs.
Mass spectrum (FAB), m/z (%): 333 (100) [M þ H]þ. Mass spectrum
(electron stroke), m/z (%): 332 (0.9) [M]þ, 314 (1.5), 245 (7), 233
(1.4), 100 (100). 1H NMR (DMSO-d6): 2.56 (t, 4H, N(CH2CH2)2O);
4.21. 6-(4-Methyl-piperazin-1-ylmethyl)-benzo[4,5]imidazo[1,2-
c]quinazoline (10e)
This compound was prepared from 8 according to the method
mentioned under the synthesis of 10a, recrystallized from heptane
in 54% yield. C20H21N5. M.W. 331.42. M.p.: 164–165 ꢀC. Rf ¼ 0.01
(eluent A), Rf ¼ 0.15 (eluent B), at UV-254 spot absorbs. Mass
spectrum (FAB), m/z (%): 332 (100) [M þ H]þ, 289, 261, 233, 220. 1H
NMR (DMSO-d6): 2.08 (s, 3H, N(CH2CH2)2NCH3); 2.25 (n/r m, 4H,
N(CH2CH2)2NCH3); 2.62 (n/r m, 4H, N(CH2CH2)2NCH3); 4.17 (s, 2H,
COCH2N); 7.47–7.58 (m, 2H); 7.70–7.75 (m, 1H); 7.80–7.85 (m, 1H);
7.92–7.94 (m, 2H); 8.05 (d, 1H); 8.55 (d, 1H).
3.00
(t,
2H,
ArCH2CH2N);
3.61–3.65
(m,
6H]4H
(N(CH2CH2)2O) þ 2H (ArCH2CH2N)); 7.46–7.56 (m, 2H); 7.64–7.70
(m, 1H); 7.77–7.87 (m, 2H); 7.93 (d, 1H); 8.17 (d, 1H); 8.51 (d, 1H).
4.26. 6-[2-(4-Methyl-piperazin-1-yl)-ethyl]-
benzo[4,5]imidazo[1,2-c]quinazoline (11e)
This compound was prepared from 9 according to the method
mentioned under the synthesis of 11a, recrystallized from iso-
propanol in 78% yield. C21H23N5. M.W. 345.45. M.p.: 97–98 ꢀC.
Rf ¼ 0 (eluent A), Rf ¼ 0.13 (eluent B), at UV-254 spot absorbs. Mass
spectrum (FAB), m/z (%): 346 [M þ H]þ, 275, 246, 113 (100). Mass
spectrum (electron stroke), m/z (%): 345 (2) [M]þ, 303 (12), 289 (5),
275 (22), 244 (20), 233 (8), 113 (81), 70 (100). 1H NMR (DMSO-d6):
2.18 (s, 3H, N(CH2CH2)2NCH3); 2.37 (n/r m, 4H, N(CH2CH2)2NCH3);
2.58 (n/r m, 4H, N(CH2CH2)2NCH3); 3.00 (t, 2H, ArCH2CH2N); 3.60 (t,
2H, ArCH2CH2N); 7.47–7.59 (m, 2H); 7.66–7.71 (m, 1H); 7.78–7.88
(m, 2H); 7.94 (t, 1H); 8.17 (d, 1H); 8.52 (d, 1H).
4.22. 6-(2-Piperidin-1-yl-ethyl)-benzo[4,5]imidazo[1,2-
c]quinazoline (11a)
To a solution of 9 (0.56 g, 0.002 mol) in methanol (50 ml) at
warming was added piperidine (0.6 ml, 0.006 mol). The reaction
mixture was boiled for 30–40 min, evaporated to 10 ml and poured
in 100 ml of distilled water. The resulting precipitate was filtered,
washed with H2O and dried. After recrystallization from iso-
propanol product was obtained with yield 0.49 g (74%). C21H22N4.
M.W. 330.44. M.p.: 119–120 ꢀC. Rf ¼ 0.01 (eluent A), Rf ¼ 0.48
(eluent B), at UV-254 spot absorbs. Mass spectrum (FAB), m/z (%):
331 (100) [M þ H]þ, 307, 246, 220, 98. 1H NMR (DMSO-d6): 1.41–
1.43 (m, 2H); 1.53–1.59 (m, 4H); 2.50 (n/r m, 4H); 2.93 (t, 2H,
ArCH2CH2N); 3.57 (t, 2H, ArCH2CH2N); 7.46–7.57 (m, 2H); 7.63–7.68
(m, 1H); 7.76–7.86 (m, 2H); 7.92 (d, 1H); 8.14 (d, 1H); 8.50 (d, 1H).
4.27. General procedure of benzimidazo[1,2-c]quinazolines
dissolution
To a suspension of benzimidazo[1,2-c]quinazoline (25–30 mg)
in methanol (0.5 ml) was added glacial acetic acid (5 ml) and
distilled water (9.5 ml). It was obtained initial solution of a ligand
‘‘L’’. The prepared solution is necessary for using (to bring to the
buffer with pH ¼ 7 or on medium of culture) during 10–12 h.
4.23. 6-[2-(2-Methyl-piperidin-1-yl)-ethyl]-benzo[4,5]imidazo[1,2-
c]quinazoline (11b)
This compound was prepared from 9 according to the method
mentioned under the synthesis of 11a, recrystallized from iso-
propanol in 64% yield. C22H24N4. M.W. 344.46. M.p.: 162–163 ꢀC.
Rf ¼ 0.06 (eluent A), Rf ¼ 0.48 (eluent B), at UV-254 spot absorbs.
Mass spectrum (FAB), m/z (%): 345 [M þ H]þ, 113 (100). Mass
spectrum (electron stroke), m/z (%): 344 (0.3) [M]þ, 244 (16), 112
(100). 1H NMR (DMSO-d6): 1.00 (d, 3H, –N(CH2CH2)2CHCH3); 1.16–
1.35 (n/r m, 2H); 1.44–1.49 (n/r m, 1H); 1.56–1.63 (m, 3H); 2.28–
2.37 (m, 1H); 2.41–2.45 (m, 1H); 2.93–3.01 (m, 2H, ArCH2CH2N);
3.34–3.40 (m, 1H); 3.56–3.62 (m, 2H, ArCH2CH2N); 7.48–7.60 (m,
2H); 7.65–7.71 (m, 1H); 7.78–7.88 (m, 2H); 7.94 (d, 1H); 8.18 (d, 1H);
8.53 (d, 1H).
4.28. General procedure of phenylbenzimidazoles dissolution
To a suspension of phenylbenzimidazole (50–65 mg) in meth-
anol (0.5 ml) was added 0.1 M solution of HCl (4 ml) and distilled
water (5.5 ml). The prepared solution is necessary for using during
24–48 h.
4.29. Procedure of preparation of initial solution for studying an
affinity into CT DNA by the ethidium bromide displacement assay
The capable of intercalating into DNA was studied by ethidium
bromide displacement assay [41]. It was prepared initial solution

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Fluorescence spectra were registered in the 560 – 800 nm range
while 535nm excitation, using standard 1sm cell. The peak of
ethidium bromide (lmax ¼ 615 nm) was marked out. Intensity of
working solutions’ fluorescence I was expressed in percentage from
intensity of control solution fluorescence. On the obtained data
dependence I, % – lgC was build.
Obtained values were approximated by sigmoid curve. The lgC50
point was determined as inflection point, and the confidence
interval – as width of 50% displacement errors corridor. From lgC50
value was determined C50, and further [41] calculated Ka.
Acknowledgements
This investigation was supported by the Department of Health
and Science of Ukraine (State Foundation for Basic Research, SFBR),
within the Grant President of Ukraine for support of young
scientists’ research from 30.01.2007. No. 18/2007; GP/134.
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