N. Kaloyanov et al. / European Journal of Medicinal Chemistry 46 (2011) 1992e1996
1995
purchased from FlukaChemieAG, Buchs, Switzerland. 5-Amino-1,10-
phenanthroline.H2O was prepared in our laboratory from 5-nitro-
1,10-phenanthroline by reduction with hydrazine hydrate using
Raney-nickel as a catalyst. All other chemicals used were of the
highest available quality. Composition of the products was deter-
mined by elemental analysis on Vario ELV5.18.018 (Elementar Ana-
lysensysteme GmbH, Hanau, Germany) performing in CHNS mode.
FAB-mass spectra were taken on a Thermo DFS High Resolution
Magnetic Sector MS Direct Probe - CI(CH4). Infrared spectra were
recorded on a PerkineElmer 1600 Series FTIR spectrophotometer in
the range of 4400e450 cmꢀ1, resolution 4 cmꢀ1, in KBr pellets. UV
spectra were recorded on UVeVIS Cary 100 instrument. X-ray
diffraction intensities were collected on a Siemens P4 diffractometer.
6.1.1.1. Preparation of (5-NH2-phen)2(phen) (H2O)3 (1). 172 mg
(0.87 mmol) phen.H2O, 185 mg (0.87 mmol) (5-NH2-phen).H2O,
274 mg (2.5 mmol) NaBF4 and 5 ml of 96% EtOH were dissolved in
30 ml distilled water at 70 ꢁC. Then the solution was brought to
ambient temperature, and distilled H2O added to 50 ml. The solu-
tion was kept in a refrigerator at 2e3 ꢁC for 30 d. The formed yel-
lowebrown crystals were filtered off, washed with distilled water
Fig. 6. Vitality (%) of human glioblastoma brain tumour cells 8-MG-BA, treated with
substances 1e5.
no case stimulated to proliferation (Fig. 6). It is worth mentioning
that at a quantity of 4.10ꢀ1 mg all tested compounds show an op-
timal suppressive effect.
In summary, it can be stated that the substances 1, 2 and 3 have
a pronounced cytotoxic effect on HEp-2 cells, substances 2,3 and 5
on 8-MG-BA cells, and substances 2 and 3 on HepG2 cells. Therefore,
molecular complexes 2 and 3 demonstrate the most outstanding
toxic effect towards all examined human tumour cell lines although
exhibiting no cytotoxicity towards the control at below 4.10ꢀ2 mg.
1,10-phenanthroline and its derivatives express different activity
to metastatic enzymes of the tumour cell matrix (MTT-enzymes).
Using quite different tumour cell lines, we can suspect such capacity
of action of our newly synthesized compounds. As shown by Gerber
et al. [12], phen has enzyme-modulatory properties in addition to its
antioxidant activity. In rat hepatocytes phen caused inhibition of
respiration and enhancement of cellular ATP content, pyruvate
release and CO2 formation from glycerol. This is a result of the phen
modulatory action on various enzymes involved in cellular energy
metabolism. Sanchez-Sweatman et al. [13] demonstrated by in vitro
experiments that prostate PC3 adenocarcinoma cell lines were not
subjected to matrix degradation after co-culturing with phen.
and ethyl ether and dried in a desiccator over P4O10
Yield: 50.6%.
.
Anal. calcd. for C36H32N8O3 (C, H, N):
Calculated (%): C, 69.15; H, 5.12; N, 17.92.
Found (%): C, 69.23; H, 5.19; N, 18.36.
FTIR (cmꢀ1): 625, 737, 843, 1409, 1488, 1618, 1651, 3237, 3348.
CIMS(CH4): 181 [phenHþ]þ.
Compounds 2, 3, 4 and 5 were prepared under identical con-
ditions to 1.
6.1.1.2. (phen)2(imidazole) (Hþ) (BF4ꢀ) (2). Yield: 50.2%.
Anal. calcd. for C27H28N6BF4 (C, H, N):
Calculated (%): C, 62.75; H, 4.06; N, 16.27.
Found (%): C, 62.93; H, 4.19; N, 16.34.
FTIR cmꢀ1: 731, 841, 1056(BF4ꢀ), 1422, 1509.
CIMS(CH4): 181 [phenHþ]þ, 196 [phen(CH4)]þ.
6.1.1.3. (phen)2(benzimidazole) (Hþ) (BF4ꢀ) (3). Yield: 38.7%.
Anal. calcd. for C29H31N6BF4 (C, H, N):
5. Conclusion
Calculated (%): C, 65.74; H, 4.06; N, 14.83.
Found (%): C, 65.31; H, 3.84; N, 14.30.
The following new compounds (5-NH2-phen)2(phen) (H2O)3 (1),
(phen)2 (imidazole) (Hþ) (BF4ꢀ) (2), (phen)2(benzimidazole) (Hþ)
(BF4ꢀ) (3), (5-NH2-phen)4 (H2O)3 (4), and (phen)3(indole) (Hþ)
FTIR cmꢀ1: 729, 839, 1058(BF4ꢀ), 1422, 1510, 1619.
CIMS(CH4): 117 [bimid]þ, 181 [phenHþ]þ, 196 [phen(CH4)]þ
ꢀ
(BF4ꢀ) (5) were synthesized by BF4 directed self-assembly. Anti-
6.1.1.4. (5-NH2-phen)4(H2O)3 (4). Yield: 49.7%.
Anal. calcd. for C48H42N12O (C, H, N):
tumour investigations of the molecular complexes 1e5 were per-
formed. As expected, the substances showed differing activities
depending on cell line and amount of the compound used.
Pronounced cytotoxic effects on HEp-2 cells were observed for 1, 2,
3, on 8-MG-BA cells for 2, 3, 5, and on HepG2 cells for 2 and 3.
Therefore, molecular complexes 2 and 3 demonstrated the most
outstanding toxic effect towards all examined human tumour cell
lines although having no cytotoxicity towards the control at
amounts below 4.10ꢀ2 mg. This is not the case with 4 and 5, which
are non-toxic to the tumour cells, but stimulate both HepG2 and
HEp-2.
Calculated (%): C, 68.98; H, 5.03; N, 20.12.
Found (%): C, 68.53; H, 4.91; N, 20.14.
FTIR cmꢀ1: 738, 1409, 1488, 1618, 1652, 3235, 3345, 3437.
6.1.1.5. (phen)3(indole) (Hþ) (BF4ꢀ) (5). Yield: 21.9%.
Anal. calcd. for C44H31N7BF4 (C, H, N):
Calculated (%): C, 70.82; H, 4.29; N, 13.14.
Found (%): C, 70.78; H, 4.09; N, 12.63.
FTIR cmꢀ1: 715, 776, 841, 1060(BF4ꢀ), 1421, 1596, 1616, 3161,
3386.
Analyses indicated by the symbols of the elements or functions
were within ꢂ0.4% of the theoretical values.
6. Experimental protocols
6.1. Chemistry
6.1.1.6. X-ray structural analysis. Compound 2 crystallizes in the
monoclinic space group P2(1)/c with a ¼ 9.359(5), b ¼ 18.578(10),
c ¼ 13.651(8) A, beta ¼ 93.01(65)ꢁ, V ¼ 2416(2) Å3. Intensity data
were collected for a crystal of 2 up to theta ¼ 25ꢁ on a Siemens P4
diffractometer at 294 K using omega scans and Mo Kalpha radiation
6.1.1. Chemicals and apparatus
1,10-Phenanthroline.H2O and NaBF4 were obtained from Merck,
Darmstadt, Germany. Imidazole, benzimidazole and indole were