Synthesis of 3-alkyl(Aryl)-4-alkylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-ones and 3-alkyl-4-alkylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones as antitumor agents

Article abstract of DOI:10.1016/S0968-0896(02)00420-0

A series of 3-alkyl-4-phenylethylidenamino- (8) and 3-alkyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (9) was synthesized from the reaction of the corresponding 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1), with phenylacetaldehyde and cinnamaldehyde. 3-Alkyl-4-(2-phenylethylamino)- (10) and 3-alkyl-4-(3-phenylpropylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (11) were obtained from the selective reduction of compounds (8) and (9) with NaBH₄. The in vitro antitumor activity of the novel compounds was screened and the highest inhibition of tree tumor cell lines was observed for the compounds containing phenylethylenamino and phenylethylamino groups at position 4 of 1,2,4-triazol ring.

Full text of DOI:10.1016/S0968-0896(02)00420-0

Bioorganic & Medicinal Chemistry 10 (2002) 3717–3723
Synthesis of 3-Alkyl(Aryl)-4-alkylidenamino-4,5-dihydro-
1H-1,2,4-triazol-5-ones and 3-Alkyl-4-alkylamino-4,5-dihydro-
1H-1,2,4-triazol-5-ones as Antitumor Agents
Neslihan Demirbas,* Reyhan Ugurluoglu and Ahmet Demirbas
Karadeniz Technical University, Department of Chemistry, 61080 Trabzon, Turkey
Received 7 May 2002; accepted 16 August 2002
Abstract—A series of 3-alkyl-4-phenylethylidenamino- (8) and 3-alkyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-1,2,4-triazol-
5-ones (9) was synthesized from the reaction of the corresponding 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1),
with phenylacetaldehyde and cinnamaldehyde. 3-Alkyl-4-(2-phenylethylamino)- (10) and 3-alkyl-4-(3-phenylpropylamino)-4,5-
dihydro-1H-1,2,4-triazol-5-ones (11) were obtained from the selective reduction of compounds (8) and (9) with NaBH4. The in vitro
antitumor activity of the novel compounds was screened and the highest inhibition of tree tumor cell lines was observed for the
compounds containing phenylethylenamino and phenylethylamino groups at position 4 of 1,2,4-triazol ring.
# 2002 Elsevier Science Ltd. All rights reserved.
Introduction
activity contain phenyl and p-tolyl groups at position 3
of the heterocycle and p-nitrophenylmethylenamino,
o-chlorophenylmethylenamino and phenylmethylenamino
groups at position 4 of the arylidenamino structure
(2–4) (Chart 1).20 In another study, some 3-alkyl-4-
(2-hydroxy-1-naphthylidenamino)- (5) and N,N0-bis(3-
alkyl-4,5-dihydro-1H-1,2,4-triazol-5-on-4-yl)-1,4-butane-
diimines (6) having antitumor activities were obtained
from the reaction of type 1 compounds with 1-hydroxy-
naphthaldehyde and 2,5-dimethoxytetrahydrofuran.21
There exist a number of 1,2,4-triazoles and 4,5-dihydro-
1H-1,2,4-triazol-5-ones having a wide range of biological
activities such as analgesic,1 antibacterial,2ꢀ7 fungi-
cidal,8,9 anti-inflammatory,10,11 antihypertensive,12,13
herbicidal,14,15 coccidiostatic,16 antiviral,17 antago-
nistic,18 controgestational19 and antitumoral.20ꢀ22
Moreover, several compounds involving 1,2,4-triazole
moiety and having divers pharmacological and anti-
tumorial activities were reported.23ꢀ29
Moreover,
N,N0-bis(3-alkyl-4,5-dihydro-1H-1,2,4-tri-
azol-5-on-4-yl)-1,4-xylenediimines (7b and 7c), having
cytostatic activity against some of the 60 tumor cell lines
were synthesized in our laboratories from the reaction
of type 1 compounds with terephthalaldehyde (Chart
1).22 Recently, 3-alkyl(aryl)-4-alkylamino-4,5-dihydro-
1H-1,2,4-triazol-5-ones have been synthesized by the
reduction of 4-alkylidenamino compounds by using
NaBH4 as a selective reducing agent.33
The chemistry of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-
1,2,4-triazol-5-one compounds (1), studied in detail by
Ikizler and coworkers30 was reported to be good
nucleophiles in most reactions. For example, 3-alkyl
(aryl)-4-alkyliden(aryliden)amino-4,5-dihydro-1H-1,2,4-
triazol-5-ones were obtained via nucleophilic attack of
amino nitrogen at position 4 on the 1,2,4-triazol-5-one
ring to carbonyl carbon of various aldehydes.30ꢀ32 It has
also been reported that the conversation of the amino
groupin 4 position at 1,2,4-triazol ring into aryliden-
amino groupcauses antitumor activity. 21 Several alkyliden
(aryliden)amino compounds were synthesized by using
type 1 compounds and reported to be antitumor active
agents. Among these, the compounds having the highest
We report here the synthesis and testing results of
potentially antitumor active 3-alkyl(aryl)-4-alkyliden
(aryliden)amino-, 3-alkyl(aryl)-4-alkyl(aryl)amino- and
1-acetyl-3-alkyl(aryl)-4-alkyliden(aryliden)amino-4,5-di-
hydro-1H-1,2,4-triazol-5-ones. 3-alkyl-4-(phenylethyl-
idenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (8) and
3-alkyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-1,2,4-
triazol-5-ones (9) were synthesized by the reaction of
type (1) compounds with phenylacetaldehyde and cinna-
maldehyde. 3-alkyl-4-(2-phenylethylamino)-4,5-dihydro-
*Corresponding author. Tel.: +90-462-377-2600; fax: +90-462-325-
3195; e-mail: neslihan@ktu.edu.tr
0968-0896/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S0968-0896(02)00420-0

3718
N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
Chart 1.
1H-1,2,4-triazol-5-ones (10) and 3-alkyl-4-(3-phenyl-
propylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (11)
were obtained by the reduction of type 8 and 9 com-
pounds with NaBH4. Furthermore, the acetylation of
compounds 8e, 9a and 9d was performed and subse-
quently 1-acetyl-3-p-tolyl-4-(2-phenylethylidenamino)-
4,5-dihydro-1H-1,2,4-triazol-5-ones (12e), 1-acetyl-3-
aryl-4-(3-phenylethylidenamino)-4,5-dihydro-1H-1,2,4-
triazol-5-ones (13a and 13d) were synthesized. (Scheme
1). All compounds, except 8d, 9e, 11d and 11e, were
selected by the National Cancer Instutite, USA and
screened for their in vitro antitumor activities.
Scheme 1. Synthetic pathway for the preparation of compounds 8–13.

N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
3719
Results and Discussion
and at the same time, this is an evidence for the reduc-
tion of this carbon atom in compounds 8 and 9 to form
10 and 11. The signal of the reduced (–NH–CH2) car-
bon atom of the compounds 10 and 11 was observed at
50 ppm in 13C NMR spectra.
Previously, the reduction of some 4-arylidenamino
compounds obtained by the reaction of type 1 com-
pounds with diverse halogenobenzaldehydes and
p-tolualdehyde has been reported.33 In the present
study, in order to improve the method, arom-aliphatic
aldehydes such as phenylacetaldehyde and cinnamal-
dehyde were used to synthesize type 8 and 9 compounds
and subsequently these products were reduced with
NaBH4 to obtain 3-alkyl-4-(2-phenylethylamino)-4,5-
dihydro-1H-1,2,4-triazol-5-ones (10) and 3-alkyl-4-(3-
phenylpropyl-amino)-4,5-dihydro-1H-1,2,4-triazol-5-ones
(11). It has been previously reported that resonance
structures may exist in the compounds containing azo-
methyne groups and these compounds may form E and
Z isomers together in diverse percentage.34 In particular
the type 9 compounds, a resonance associated with both
azomethyne and allyl groups may exist (Scheme 2).
Together with azomethyne group, the carbon–carbon
double bond in type 9 compounds was probably due to
this resonance, reduced with NaBH4. As a result of
these resonance structures, one carbon atom of carbon–
carbon double bond in compounds 9 should be more
electropositive than the other. Therefore, this situation
may facilitate the attack of hydride ion of NaBH4 to
this carbon atom. Furthermore, only one signal was
observed in 13C NMR spectra indicating the formation
of either E or Z isomer.
The growth inhibition properties of the selected com-
pounds by the National Cancer Institute, USA were
screened on three human tumor cell lines, breast Cancer
(MCF7), non small cell lung cancer (NCI-H460) and
CNS (SF-268) as listed in Table 1. From the point of a
structure–activity relationship, the results obtained
reveal that an antitumor property appears as a result of
the conversion of 4-amino-4,5-dihydro-1H-1,2,4-triazol-
5-ones 1 into 4-alkylidenamino- or 4-alkylamino-4,5-
dihydro-1H-1,2,4-triazol-5-ones and 1-acetyl-derivative
of compound 8e whereas type 1 compounds are known
as antitumor inactive.21 The highest activity was
observed for phenylethylidenamino and phenylethyl-
amino groups at position 4 of the heteroring. The com-
pounds 9b and 9c containing 3-phenylallylidenamino
groupat position 4 of 1,2,4-triazol ring have less cyto-
static effect against two cell line than formers.
According to the results obtained, 3-alkyl-4-alkyliden
(or alkyl)amino-4,5-dihydro-1H-1,2,4-triazol-5-ones can
be described as a new class of antitumor agents. Which
served us to search structural modifications in 4,5-di-
hydro-1H-1,2,4-triazol-5-one ring for designing poten-
tially antitumor active 1,2,4-triazol-5-one systems.
The exocyclic–NH signals were observed at 5–6 ppm in
the compounds 10, 11 while endocyclic –NH proton
signals were seen at 10–12 ppm as expected for all. In
Experimental
Chemistry
1
presence of D2O, the singlet signals disappeared in H
NMR spectra and the –N¼CH proton signal of com-
pounds 8 and 9 were recorded at 9–10 ppm. These sig-
nals disappeared when the compounds 10 and 11
formed. Instead, a new signal at 3–3.5 ppm belonging to
methylenic protons of –NH–CH2 groupof compounds
Melting points were determined on a Gallenkamp melt-
1
ing point apparatus and are uncorrected. H NMR and
13C NMR spectra were recorded on a Varian-Mercury
200 MHz spectrophotometer. The IR spectra were mea-
sured as potassium bromide pellets using a Perkin-Elmer
1600 series FTIR spectrophotometer. The ultraviolet
1
10 and 11 was seen. In the H NMR spectra of com-
pounds 12 and 13, a new additional signal belonging to
methyl protons of acetyl group was recorded at 2.5
ppm. The signals belonging to carbonyl carbon and
methyl carbon of acetyl group were seen at 166 ppm and
23.5 ppm in 13C –NMR spectra of compounds 12 and
13. The –N¼CH carbon signal of compounds 8, 9, 12
and 13 was recorded at 156–160 ppm. The dis-
appearance of this signal in the case of compounds 10
and 11 indicates that this signal belongs to the carbon atom
of –N¼CH groupof compounds 8 and 9, respectively,
Table 1. Antitumor screening data for the selected compounds
Compd Number assigned
by NCI
Growth percentage of tumor cell
MCF7
NCI-H460
SF-268
8a
8b
8c
8e
9a
9b
9c
9d
10a
10b
10c
10d
10e
12e
13a
13d
S723464
S723465
S723466
S723467
S723036
S723038
S723220
S723039
S723461
S723462
S723463
S723459
S723460
S723468
S723217
S723218
111
120
130
0
94
37
73
32
0
135
105
0
118
0
0
0
0
0
116
0
0
0
93
17
67
22
0
0
0
0
0
81
49
98
52
0
0
0
0
0
0
99
95
0
118
119
119
121
Scheme 2. Resonance structures of 4-(3-phenylallylidenamino) deri-
vatives 9, 13.

3720
N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
absorption spectra were measured between 200–400 nm
on a Schimadzu 1202 UV–vis spectrometer using 10 mm
quartz cells. Combustion analysis was performed on a
Carlo Erba 1106 elemental analyzer. The chemicals were
obtained from Fluka Chemie AG Buchs (Switzerland).
Compounds 1 and 2 were synthesized according to the
published methods.4,22
(2CH), 127.90 (2CH), 126.50 (C)], 40.01 (CH2), 29.95
(CH2).
3-Phenyl-4-phenylethylidenamino-4,5-dihydro-1H-1,2,4-
triazol-5-one (8d). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from benzene to afford the desired com-
pound (yield: 1.40 g, 50.35%). Mp 176–177 ꢁC. Analysis
(% calcd/found): for C16H14ON4 C: 69.05/68.27, H:
5.07/4.92, N: 20.13/20.97; IR (KBr) cmꢀ1: 3167 (nNH),
General method for synthesis of 3-alkyl(aryl)-4-
phenylethylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-
ones (8)
1
1691 (nC¼O), 1552 (nC¼N); H NMR (DMSO-d6) d 3.75
(d, CH2, J=5.2 Hz), 9.20 (t, N¼CH, J=5.2 Hz), 7.86 (bs,
2H), 7.28–7.43 (m, 10H), 10.92 (s, NH); 13C NMR
(DMSO-d6) d 161.01 (N¼CH), 152.40 (triazole C3),
145.95 (triazole C5), Ar C :[135.30 (C), 130.31 (CH),
129.18 (2CH), 128.88 (2CH), 128.34 (4CH), 127.12 (CH),
126.50 (C)], 40.16 (CH2).
The corresponding 3-alkyl-4-amino-4,5-dihydro-1H-
1,2,4-triazol-5-one (1) (0.01 mol) was heated in an oil
bath with phenylacetaldehyde (2.11 mL, 0.01 mol) at
150–160 ꢁC for 2 h. After cooling the mixture to room
temperature, a solid appeared, and it was recrystallized
from an appropriate solvent to afford the desired
compound.
3-(p-Tolyl)-4-phenylethylidenamino-4,5-dihydro-1H-1,2,4-
triazol-5-one (8e). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from ethylacetate to afford the desired
compound (yield: 1.31 g, 44.86%). Mp 176–177ꢁC. Ana-
lysis (% calcd/found): for C17H16ON4 C: 69.84/69.80, H:
5.52/5.42, N: 19.17/18.63; IR (KBr) cmꢀ1: 3164 (nNH),
1694 (nC¼O), 1590 (nC¼N); 1H NMR (DMSO-d6) d 2.40 (s,
CH3), 3.75 (d, CH2, J=5.6 Hz), 9.16 (t, N¼CH, J=5.6
Hz), 7.74–7.10 (m, 7H), 7.78 (d, 2H, J=8.0 Hz), 10.34 (s,
NH); 13C NMR (DMSO-d6) d 160.79 (N¼CH), 152.24
(triazole C3), 145.88 (triazole C5), Ar C: [140.53 (C),
135.02 (C), 129.16 (2CH), 129.11 (2CH), 128.23 (2CH),
127.09 (CH), 123.580 (C)], 40.16 (CH2), 21.51 (CH3).
3-Methyl-4-phenylethylidenamino-4,5-dihydro-1H-1,2,4-
triazol-5-one (8a). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from benzene–petroleum ether (1:3) to
afford the desired compound (yield: 1.06 g, 49.23%).
Mp126–127 ꢁC. Analysis (% calcd/found): for
C11H12ON4 C: 61.09/60.75, H: 5.59/5.96, N: 25.91/
26.71; IR (KBr) cmꢀ1: 3182 (nNH), 1899 (nC¼O), 1593
1
(nC¼N); H NMR (DMSO-d6) d 2,30 (s, CH3), 3.70 (d,
CH2, J=5.8 Hz), 9.20 (t, N=CH, J=5.8 Hz), 7.75–7.36
(m, 5H), 10.25 (s, NH); 13C NMR (DMSO-d6) d 158.90
(N¼CH), 152.30 (triazole C3), 145.40 (triazole C5), Ar C
: [135.40 (C), 129.02 (2CH), 128.85 (2CH), 127.07
(CH)], 40.19 CH2), 11.52 (CH3).
General method for synthesis of 3-alkyl(aryl)-4-(3-
phenylallylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-
ones (9)
3-Benzyl-4-phenylethylidenamino-4,5-dihydro-1H-1,2,4-
triazol-5-one (8b). Following the general procedure
reported above, a white solid was obtained. This was
recrystallized from benzene to afford the desired com-
pound (yield: 1.35 g, 46.23%). M.p. 163–164 ꢁC. Ana-
lysis (% calcd/found): for C17H16ON4 C: 69.84/70.01;
H: 5.52/5.78, N: 19.17/19.20; IR (KBr) cmꢀ1: 3182
The corresponding 3-alkyl-4-amino-4,5-dihydro-1H-
1,2,4-triazol-5-one (1) (0.01 mol) was heated in an oil
bath with cinnamaldehyde (1.25 mL, 0.01 mol) at 120–
130 ꢁC for 2 h. After cooling the mixture to room tem-
perature, a solid appeared. It was recrystallized from an
appropriate solvent to afford the desired compound.
1
(nNH), 1690 (nC¼O), 1550 (nC¼N); H NMR (DMSO-d6)
d 3.65 (d, CH2, J=5.8 Hz), 4.00 (s, CH2), 9.10 (t,
N¼CH, J=5.4 Hz), 7.10–7.35 (m, 10H), 10.60 (s, NH);
13C NMR (DMSO-d6) d 158.90 (N¼CH), 152.30 (tria-
zole C3), 147.20 (triazole C5), Ar C: [135.30 (2C), 129.10
(2CH), 129.04 (2CH), 128.722 (CH), 128.53 (2CH),
126.97 (2CH)], 40.19 (CH2), 11.52 (CH3).
3-Methyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-
1,2,4-triazol-5-one (9a). Following the general proce-
dure reported above, a white solid was obtained. It was
recrystallized from chloroform–ethylacetate (1:3) to
afford the desired compound (yield: 1.90 g, 83.33%).
Mp221–224 ꢁC. Analysis (% calcd/found): for
C12H12ON4 C: 63.14/62.58, H: 5.30/5.10, N: 24.55/
24.92; IR (KBr) cmꢀ1: 3177 (nNH), 1703 (nC¼O), 1595
3-(p-Chlorobenzyl)-4-phenylethylidenamino-4,5-dihydro-
1H-1,2,4-triazol-5-one (8c). Following the general pro-
cedure reported above, a white solid was obtained. It
was recrystallized benzene to afford the desired com-
pound (yield: 1.52 g, 46.62%). Mp 189–190 ꢁC. Analysis
(% calcd/found): for C17H15ON4Cl C: 62.48/63.051; H:
4.62/4.71, N: 17.14/16.93; IR (KBr) cmꢀ1: 3168 (nNH),
1690 (nC¼O), 1595 (nC¼N); 1H NMR (CDCl3) d 3.70 (d,
CH2, J=5.8 Hz), 3.98 (s, CH2), 9.05 (t, N¼CH,
J=5.4 Hz), 7.15–7.40 (m, 9H), 10.90 (s, NH); 13C
NMR (CDCl3) d 158.10 (N¼CH), 151.05 (triazole C3),
145.05 (triazole C5), Ar C: [135.10(C), 134.02 (2CH),
130.95 (2CH), 130.02 (2CH), 128.02 (2CH), 127.95
1
(nC¼N); H NMR (CDCl3) d 2.21 (s, CH3), 7.10 (dd,
CH, Jab=9.4, Jbc=16), 7.40 (Jbc=16), 9.55 (d, N¼CH,
J=9.4 Hz), 6.97–7.10 (m, Ar–H, 6H), 11.81 (s, NH);
13C NMR (DMSO-d6) d 156.33 (N¼CH), 151.34 (tria-
zole C3), 144.10 (triazole C5), Ar C: [135.47 (C), 129.05
(2CH), 127.73 (2CH), 125.05 (CH)], 11.38 (CH3).
3-Benzyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-
1,2,4-triazol-5-one (9b). Following the general procedure
reported above, a white solid was obtained. It was recrys-
tallized from ethyl acetate to afford the desired compound

N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
3721
(yield: 2.50 g, 82.23%). Mp199–200 ꢁC. Analysis (%
calcd/found): for C13H16ON4 C: 71.03/71.62, H: 5.30/4.92,
N: 18.4/17.91; IR (KBr) cmꢀ1: 3165 (nNH), 1689 (nC¼O),
1588 (nC¼N) ); 1H NMR (DMSO-d6) d 4.10 (s, CH2), 7.69
(dd, CH, Jab=9.3 Hz, Jbc=16 Hz, 7.10 Jbc=16 Hz), 9.55
(d, N¼CH, J=9.4 Hz), 7.20–7.45 (m, Ar–H, 8H), 7.50 (d,
Ar–H, 2H), 10.60 (s, NH); 13C NMR (CDCl3) d 156.70
(N¼CH), 152.08 (triazole C3), 147.28 (triazole C5), Ar C :
[135.40 (C), 134.97 (C), 129.03 (2CH), 128.80 (2CH),
127.40 (2CH), 127.01 (CH), 125.04 (CH)], 31.53 (CH2).
0.03 mol) in 30 mL diglime. Then, the mixture was
refluxed for 8 h and subsequently, was poured in 500
mL water. On cooling in deepfreeze, a solid appeared.
It was recrystallized from an appropriate solvent to
afford the desired compound.
3-Methyl-4-(2-phenylethylamino)-4,5-dihydro-1H-1,2,4-
triazol-5-one (10a). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from benzene–n-hexane (1:3) to afford
the desired compound (yield: 1.09 g, 50.0%). Mp 115–
116 ꢁC. Analysis (% calcd/found): for C18H14ON4 C:
60.53/60.17, H: 6.47/7.07, N: 25.67/25.93; IR (KBr)
3-(p-Chlorobenzyl)-4-(3-phenylallylidenamino)-4,5-dihydro-
1H-1,2,4-triazol-5-one (9c). Following the general pro-
cedure reported above, a white solid was obtained. It
was recrystallized from chloroform–ethyl acetate (1:2)
to afford the desired compound (yield: 2.82 g, 82.84%).
Mp229–230 ꢁC. Analysis (% calcd/found): for
C13H16ON4Cl C: 63.81/63.27, H: 4.46/4.82, N: 16.53/
16.82; IR (KBr) cmꢀ1: 3177 (nNH), 1703 (nC¼O), 1595
(nC¼N); 1H NMR (CDCl3) d 4.00 (s, CH2), 7.05 (dd, CH
Jab=9 Hz, Jbc=16), 7.25 (d, J=16 Hz), 9.50 (d, N¼CH,
J=9.2 Hz), 7.30–7.50 (m, Ar–H, 7H), 7.65–7.70 (m, 2H),
12.00 (s, NH); 13C NMR (DMSO-d6) d 156.05 (N¼CH),
151.30 (triazole C3), 145.50 (triazole C5), Ar C: [135.47
(C), 134.50 (C), 131.40 (C), 130.70 (2CH), 128.22 (2CH),
127.48 (2CH), 124.70 (CH)], 30.03 (CH2).
1
cmꢀ1: 3177, 3250 (nNH), 1706 (nC¼O), 1590 (nC¼N); H
NMR (DMSO-d6) d 2.05 (s, CH3), 2.70–2.80 (m,
CH2), 3.20–3.30 (m, NHCH2), 6.05 (s,NNH), 7.20–
7.38 (m, Ar-H, 5H), 11.40 (s, NH); 13C NMR
(DMSO-d6) d 154.03 (triazole C3), 145.63 (triazole C5),
Ar C: [139.48 (C), 128.38 (2CH), 126.66 (2CH), 128.66
(2CH), 126.13 (CH)], 50.52 (CH2), 33.79 (CH2), 10.86
(CH3).
3-Benzyl-4-(2-phenylethylamino)-4,5-dihydro-1H-1,2,4-
triazol-5-one (10b). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from acetone–water (1:3) to afford the
desired compound (yield: 1.66 g, 56.46%). Mp 115–
116 ꢁC. Analysis (% calcd/found): for C17H18ON4 C:
69.37/68.65, H: 6.16/6.54, N: 19.04/18.31; IR (KBr)
3-Phenyl-4-(3-phenylallylidenamino)-4,5-dihydro-1H-
1,2,4-triazol-5-one (9d). Following the general proce-
dure reported above, a white solid was obtained. It was
recrystallized from benzene to afford the desired com-
pound (yield: 1.95 g, 67.24%). Mp 196–197ꢁC. Analysis
(% calcd/found): for C17H14ON4 C: 41.42/41.88, H: 2.85/
3.12, N: 11.32/11.82; IR (KBr) cmꢀ1: 3158 (nNH), 1694
1
cmꢀ1: 3231, 3166 (nNH), 1702 (nC¼O), 1585 (nC¼N); H
NMR (DMSO-d6) d 2.52–2.65 (m, CH2), 3.75 (s, CH2)
3.20–3.30 (m, NHCH2), 6.05 (bs, NNH), 7.10–7.40 (m,
Ar–H, 10H), 11.52 (s, NH), 13C NMR (CDCl3) d 153.52
(triazole C3), 147.08 (triazole C5), Ar C: [138.86 (C),
135.61 (C), 128.29 (C), 128.07 (2CH), 128.04 (2CH),
127.92 (2CH), 127.78 (CH), 124.14 (CH)], 49.89 (CH2),
33.02 (CH2), 30.30 (CH2).
1
(nC¼O), 1623 (nC¼N); H NMR (DMSO-d6) d 6,95 (dd,
CH Jab=9 Hz, Jbc=16 Hz, 7.15 (d, J=16 Hz), 9.60 (d,
N¼CH, J=9.2 Hz), 7.20–7.60 (m, Ar–H, 5H), 7.90–8.02
(m, Ar–H, 5H), 10.82 (s, NH); 13C NMR (CDCl3) d 158.50
(N¼CH), 152.50 (triazole C3), 146.01 (triazole C5), 144.02
(CH), 129.30 (CH), Ar C: [135.30 (C), 130.03 (C), 128.80
(2C), 128.48 (2C), 127.40 (2C), 126.50 (C), 124.80 (C)].
3-(p-Chlorobenzyl)-4-(2-phenylethylamino)-4,5-dihydro-
1H-1,2,4-triazol-5-one (10c). Following the general pro-
cedure reported above, a white solid was obtained. It
was recrystallized from acetone–water (1:3) to afford the
desired compound (yield: 1.70 g, 51.82%). M.p. 151–
152 ꢁC. Analysis (% calcd/found): for C17H18ON4Cl C:
62.10/61.71: H: 5.21/4.88, N: 17.03/17.70; IR (KBr)
3-(p-tolyl)-4-(3-phenylallylidenamino)-4,5-dihydro-1H-
1,2,4-triazol-5-one (9e). Following the general proce-
dure reported above, a white solid was obtained. It was
recrystallized from benzene to afford the desired com-
pound (yield: 2.10 g, 69.07%). Mp 215–216 ꢁC. Analysis
(% calcd/found): for C18H16ON4 C: 70.03/70.86, H:
5.30/5.32, N: 18.41/18.30; IR (KBr) cmꢀ1: 3163 (nNH),
1
cmꢀ1: 3229, 3179 (nNH), 1727 (nC¼O), 1590 (nC¼N); H
NMR (CDCl3) d 2.60–2.75 (m, CH2), 3.75 (s, CH2),
2.90–3.10 (m, NHCH2), 4.54 (t, NNH, J=6.4 Hz),
7.05–7.30 (m, Ar–H, 9H), 10.30 (s, NH); 13C NMR
(CDCl3) d 154.03 (triazole C3), 147.05 (triazole C5), Ar
C:[138.03 (C), 135.02 (C), 133.28 (C), 130.12 (2CH),
128.60 (2CH), 128.48 (2CH), 126.31 (CH)], 50.03 (CH2),
33.90 (CH2), 30.80 (CH2).
1
1694 (nC¼O), 1625 (nC¼N); H NMR (CDCl3) d 2.40 (s,
CH3), 7.10 (dd, CH Jab=9.0 Hz, Jbc=16 Hz), 7.30 (d,
J=16 Hz), 9.45 (d, N¼CH, J=9.0 Hz), 7.30–7.50 (m, Ar–
H, 5H), 7.62–7.90 (m, Ar–H, 4H),12.30 (s, NH); 13C
NMR (DMSO-d6) d 158.03 (N¼CH), 150.08 (triazole C3),
143.80 (triazole C5), 143.05 (CH), 129.03 (CH), Ar C:
[134.02 (C), 130.01 (C), 129.03 (2C), 128.01 (2C), 127.02
(2C), 127.00 (2C), 124.03 (C), 126–3.05 (C)], 20.05 (CH3).
3-Phenyl-4-(2-phenylethylamino)-4,5-dihydro-1H-1,2,4-
triazol-5-one (10d). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from chloroform–n-hexane (1:3) to afford
the desired compound (yield: 50%). Mp 166–167 ꢁC.
Analysis (% calcd/found): for C16H16ON4 C: 68.55/
General method for synthesis of 3-alkyl(aryl)-4-(2-
phenylethylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (10)
68.75: H: 5.75/5.60, N: 19.99/19.52; IR (KBr) cmꢀ1
3237,3154 (nNH), 1702 (nC¼O), 1519 (nC¼N); H NMR
(DMSO-d6) d 2.60–2.70 (m, CH2), 2.95–3.10 (m,
:
1
A solution of corresponding compound (8) (0.01) in 40
mL diglime was treated with a solution of NaBH4 (1.11 g,

3722
N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
NHCH2), 6.20 (t, NNH, J=6.5 Hz), 7.18–7.50 (m, Ar–
H, 8H), 7.85 (d, 2H, Ar–H, J=8.0 Hz), 11.90 (s, NH);
13C NMR (DMSO-d6) d 154.05 (triazole C3), 144.08
(triazole C5), Ar C:[139.05 (C), 129.08 (2CH), 128.80
(2CH), 128.29 (2CH), 128.25 (2CH), 127.04 (2CH),
127.03 (C), 126.11 (CH)], 50.08 (CH2), 33.50 (CH2).
(C),129.41 (2CH), 128.32 (3CH), 127.33 (2CH), 126.24
(CH), 125.67 (CH), 124.38 (C)], 48.70 (CH2), 32.65
(CH2), 29.29 (CH2), 21.08 (CH3).
1-Acetyl-3-(p-tolyl)4-phenylethylydenamino-4,5-dihydro-
1H-1,2,4-triazol-5-one (12e). Compound (8e) (2.92 g,
0.01 mol) was refluxed with 10 mL acetic anhydride for
2 h. Then, the mixture was cooled to room temperature
and added 40 mL ethanol and than refluxed 30 min. On
cooling the mixture in the deep-freeze a solid appeared.
This crude product was crystallized from benzene–pet-
roleum ether (1:2) to give compound (12e) (yield: 2.00 g,
3-(p-tolyl)-4-(2-phenylethylamino)-4,5-dihydro-1H-1,2,4-
triazol-5-one (10e). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from acetone–water (1:3) to afford the
desired compound (yield: 1.94 g, 65.68%). Mp 163–
164 ꢁC. Analysis (% calcd/found): for C17H18ON4 C:
69.37/69.05, H: 6.59/5.97, N: 19.04/19.28; IR (KBr)
ꢁ
59.88%). Mp102–103 C. Analysis (% calcd/found): for
C19H18O2N4 C: 68.24/69.64, H: 5.42/5.02, N: 16.76/
16.92; IR (KBr) cmꢀ1, 1731, 1725 (nC¼O), 1517 (nC¼N);
1H NMR (DMSO-d6) d 2.64 (s, CH3), 2.42 (s, CH3),
3.78 (d, CH2, J=5.6 Hz), 9.09 (d, N¼CH, J=5.6 Hz),
7.40–7.82 (m, Ar–H, 9H); 13C NMR (CDCl3) d 162.31
(triazole C3), 148.90 (triazole C5), Ar C: [141.82 (C),
134.90 (C), 129.14 (3CH), 129.12 (3CH), 127.90 (CH),
127.21 (2CH), 122.40 (C)], 40.08 (CH2), 23.70 (CH3),
21.58 (CH3).
1
cmꢀ1: 3274,3156 (nNH), 1702 (nC¼O), 1518 (nC¼N); H
NMR (CDCl3) d 2.37 (s, CH3), 2.77 (t, CH2, J=7.0
Hz), 3.22–3.35 (m, NHCH2), 5.00 (t, NNH, J=6.4 Hz),
7.05–7.30 (m, Ar–H, 7H), 7.85 (d, 2H, Ar–H, J=8.2 Hz),
11.05 (s, NH); 13C NMR (CDCl3) d 155.03 (triazole C3),
145.08 (triazole C5), Ar C: [140.08 (C), 138.80 (C), 129.44
(2CH), 128.99 (2CH), 128.74 (2CH), 127.51 (2CH), 126.66
(CH), 123.90 (C)], 51.97 (CH2), 34.33 (CH2), 19.95 (CH3).
General method for synthesis of 3-alkyl(aryl)-4-(3-
phenylpropylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones
(11)
General method for synthesis of 1-acetyl-3-alkyl(aryl)-4-
(3-phenylallylydenamino)-4,5-dihydro-1H-1,2,4-triazol-5-
ones (13)
A solution of corresponding compound (9) (0.01) in 40
mL diglime was treated with a solution of NaBH4 (1.11
g, 0.03 mol) in 30 mL diglime. Then, the mixture was
refluxed for 8 h and subsequently was poured in 500 mL
water. On cooling in deep freeze, a solid appeared. It
was recrystallized from an appropriate solvent to afford
the desired compound.
The corresponding compound (9) (0.01 mol) was
refluxed with 10 mL acetic anhydride for 2 h. Then, the
mixture was cooled to room temperature and added 40
mL ethanol and than refluxed 30 min. After evaporated
at 35–40 ꢁC under reduced pressure a solid appeared.
This was recrystallized from an appropriate solvent to
afford desired compound.
3-Phenyl-4-(3-phenylpropylamino)-4,5-dihydro-1H-1,2,4-
triazol-5-one (11d). Following the general procedure
reported above, a white solid was obtained. It was
recrystallized from ethanol–water (1:3) to afford the
desired compound (yield: 1.50 g, 51.02%) Mp 147–
148 ꢁC. Analysis (% calcd/found): for C17H18ON4 C:
69.37/68.87, H: 6.16/15.97, N: 19.04/18.6; IR (KBr)
1-Acetyl-3-phenyl-4-(3-phenylallylydenamino)-4,5-dihydro-
1H-1,2,4-triazol-5-one (13a). Following the general pro-
cedure reported above, a white solid was obtained. It
was recrystallized from benzene–petroleum ether (1:2) to
afford desired compound (yield: 1.82 g, 67.40%) Mp
168–169 ꢁC. Analysis (% calcd/found): for C14H14O2N4
C: 62.21/69.64, H: 5.22/5.20, N: 20.73/19.98; IR (KBr)
1
1
cmꢀ1: 3248,3152 (nNH), 1703 (nC¼O), 1515 (nC¼N); H
cmꢀ1, 1727 (n2C¼O), 1616 (nC¼N); H NMR (CDCl3) d
NMR (CDCl3) d 1.65–1.80 (m, CH2), 2.50–2.65 (m,
CH2), 3.37 (q, NHCH2, J=7.0 Hz), 5.08 (t, NNH, J=5.4
Hz), 6.95–8.10 (m, Ar–H, 10H), 11.30 (s, NH); 13C NMR
(CDCl3) d 154.32 (triazole C3), 145.35 (triazole C5), Ar C:
[131.05 (C), 129.98 (2C), 128.53 (2C), 127.41(3C), 127.13
(2C), 125.79 (C)], 48.60 (CH2), 32.59 (CH2), 29.14 (CH2).
2.36 (s, CH3), 2.60 (s, CH3), 9.48 (d, N¼CH, J=9.4
Hz), 7.58–7.50 (m, Ar–H, 2H); 7.33–7.42 (m, Ar–H,
2H); 13C NMR (CDCl3) d 157.52 (triazole C3), 147.50
(triazole C5), 148.20 (N¼CH), 144.45 (CH), 125.60
(CH), Ar C: [135.12 (C), 129.89 (CH), 128.91 (CH),
127.53 (2CH), 124.60], 23.28 (CH3), 11.658 (CH3).
3-(p-Tolyl)-4-(3-phenylpropylamino)-4,5-dihydro-1H-
1,2,4- triazol-5-one (11e). Following the general proce-
dure reported above, a white solid was obtained. It was
recrystallized from ethanol–water (1:3) to afford the
desired compound (yield: 1.53 g, 49.67%). Mp 147–
149 ꢁC. Analysis (% calcd/found): for C18H20ON4 C:
70.10/69.64, H: 6.54 /6.89, N: 18.17/18.76; IR (KBr)
1-Acetyl-3-phenyl-4-(3-phenylallylidenamino)-4,5-dihydro-
1H-1,2,4-triazol-5-one (13d). Following the general pro-
cedure reported above, a white solid was obtained. It
was recrystallized from from benzene–petroleum ether
(1:2) to afford desired compound (yield: 2.50 g, 75.30%)
Mp167–168 ꢁC. Analysis (% calcd/found): for
C19H16O2N4 C: 68.66/69.03, H: 4.85/4.80, N: 16.86/
16.70; IR (KBr) cmꢀ1, 1780, 1778 (nC¼O), 1619 (nC¼N);
1H NMR (DMSO-d6) d 2.57 (s, CH3), 9.28 (d, N¼CH,
J=9.2 Hz), 7.95–7.85 (m, Ar–H, 2H), 7.80–7.65 (m, Ar–
H, 2H), 7.65–7.45 (m, Ar–H, 3H), 7.45–7.40 (m, Ar–H,
3H); 13C NMR (CDCl3) d 161.00 (N¼CH), 148.02 (tri-
azole C3), 145.28 (triazole C5), 145.23 (CH), 124.14
1
cmꢀ1: 3250, 3163 (nNH), 1703 (nC¼O), 1509 (nC¼N); H
NMR (DMSO-d6) d 2.35 (s, CH3),1.50–1.70 (m, CH2),
2.45–2.50 (m, CH2), 3.13.30 (m, NHCH2,), 6.20 (t,
NNH, J=5.4 Hz), 6.98–7.93 (m, Ar–H, 9H), 11.94 (s,
NH); 13C NMR (DMSO-d6) d 154.43 (triazole C3),
145.50 (triazole C5), Ar C: [132.20 (C), 132.30

N. Demirbacs˛ et al. / Bioorg. Med. Chem. 10 (2002) 3717–3723
3723
(CH), Ar C: [135.00 (2C), 131.50 (CH), 129.98 (CH),
128.52 (2CH), 127.76 (4CH), 125.98 (CH)], 23.47 (CH3).
11. Wade, P. C.; Vogt, B. R.; Kissick, T. P.; Simkins, L. M.;
Palmer, D. M.; Millonig, R. C. J. Med. Chem. 1982, 25, 331.
12. Emilsson, H.; Selander, H.; Gaarder, J. Eur. J. Med.
Chem. Chim. Ther. 1985, 21, 333.
Pharmacology
13. Emilsson, H.; Luthman, K.; Selander, H. J. Med. Chem.
Chim. Ther. 1986, 21, 235.
All compounds, except 8d, 9e, 11d and 11e, were selec-
ted by the National Cancer Instutite, USA for screening
towards in vitro three human tumor cell lines, breast
Cancer (MCF7), non small cell lung cancer (NCI-H460)
and CNS (SF-268). Each cell line was inoculated and
preincubated on a microtiter plate. Test agents were
then added at a single concentration and culture incu-
bated for 48 h. End-point determinations were made
with alamar blue.35
14. Lindig, M.; Findeisen, K.; Mueller, K. H.; Santel, H. J.;
Schmidt, R. R.; Strang, H.; Feucht, D. Eur. Pat. Appl. EP,
294, 666, 14 Dec 1988; Chem. Asstr. 1989, 11, 174097n.
15. Mueller, K. H.; Lindig, M.; Findeisen, K.; Koenig, K.;
Luerssen, K.; Santel, H. J.; Schimdt, R. R.; Strang, H. Ger
(East) DD., 298, 393, 20 February 1992; chem Asstr. 1992,
117, 48571y.
16. Mano, M.; Matsuno, T.; Imai, K. Chem. Pharm. Bull.
1976, 24, 2871.
17. Somorai, T.; Szilagyi, G.; Reiter, J.; Pongo, L.; Lang, T.;
Toldy, L.; Horvarth, S. Arch. Pharm. (Weinheim) 1987, 320,
554.
Acknowledgements
18. Bonjean, J.; Schunack, W. Arch. Pharm. (Weinheim)
1987, 320, 554.
This work was supported by the Research Fund of
Karadeniz Technical University. The authors thank the
National Cancer Instutite, USA, for antitumor screen-
ing results and Dr. S. Guner (KTU, Department of
Chemistry) for critical reading of the manuscript.
19. Omodei-Sale, A.; Consonni, P.; Galliani, G. J. Med.
Chem. 1983, 26, 1187.
20. Ikizler, A. A.; Ikizler, A.; Serdar, M.; Yıldırım, N. Acta
Pol. Pharm. Drug Res. 1997, 54, 360.
21. Ikizler, A. A.; Ikizler, A.; Yuksek, H.; Serdar, M. M.
Model. Meas. Cont. C 1997, 57, 25.
22. Ikizler, A. A.; Uzunali, E.; Demirbas, A. Indian J. Pharm.
2000, 5, 289.
23. Turan-Zitouni, G.; Sıvacı, M. F.; Kılıc, S. Erol, K. Eur. J.
Med. Chem. 2001, 36, 685.
24. Varvarasou, A.; Siatra-Papastaikoudi, T.; Tsotunis, A.; Tsa-
References and Notes
1. Clemense, F.; Joliveau-Maushart, C.; Meier, J.; Cereda, J.;
Delevallee, F.; Benzoni, J.; Deraedt, R. Eur. J. Med. Chem.
Chim. Ther. 1985, 20, 250.
2. Ikizler, A.; Gumus, F.; Ozden, S.; Abbasodlu, U. Pharma-
tili-Kakoulidou, A.; Vamvakides, A. IL Farmaco 1998, 53, 320.
.
.
25. Addel, M.; Ismail, H. Heterocycles 1999, 51, 379.
26. Modzelowska-Banachiewicz, B.; Kaminska, T. Eur. J.
Med. Chem. 2001, 36, 93.
27. Demirayak, S.; Benkli, K.; Guven, K. Eur. J. Med. Chem.
2000, 35, 1037.
28. Ulusoy, N.; Gursoy, A.; Otuk, G. IL Farmaco 2001, 56,
947.
29. Baraldi, P. G.; Pavani, M. G.; Nunez, M. C.; Brigidi, P.;
Vitali, B.; Gambari, R.; Romagnoli, R. Bioorg. and Med.
Chem. 2002, 449.
zie 1989, 44, 506.
3. Yuksek, H.; Demirbas, A.; Ikizler, A.; Johansson, C. B.;
.
.
Celik, C.; Ikizler, A. A. Arzneim Forsh. Drug Res. 1997, 47, 405.
.
4. Demirbas, A.; Johansson, C. B.; Duman, N.; Ikizler, A. A.
Acta Pol. Pharm. Drug Res. 1996, 53, 117.
5. Malbec, F.; Milcent, R.; Vicart, P.; Bure, A. M. J. Hetero-
cycl. Chem. 1984, 21, 1769.
6. Milcent, R.; Vicart, P. Eur. J. Med. Chem. Chim. Ther.
1983, 18, 215.
.
7. Ikizler, A. A.; Ucar, F.; Demirbas, N.; Yasa, I.; Demirbas,
A.; Genzer, T. Ind. J. Pharm. Sci. 1999, 61, 271.
8. Chollet, J.-F.; Bonnemain, J.-L.; Miginiac, L.; Rohr, O.
Pesticide Sci. 1990, 29, 422.
30. Ikizler, A.; Sancak, K. Rov. Roumaine Chim. 1998, 43, 133.
31. Ikizler, A. A.; Un, R. Chem. Acta Turc. 1979, 7, 269.
32. Ikizler, A. A.; Ikizler, A.; Yıldırım, N. Monatsch Chem.
1991, 122, 557.
9. Murabayashi, A.; Masuko, M.; Niikawa, M.; Shirane, N.;
Futura, T.; Hayashi, Y.; Makisumi, Y. J. Pesticide Sci. 1991,
16, 419.
33. Kahveci, B.; Ikizler, A. A. Turk. J. Chem. 2000, 24, 343.
34. Mamolo, M. G.; Falagiani, V.; Zampieri, D.; Vio, L.;
Banfi, E. IL Farmaco 2001, 56, 587.
10. Gruta, A. K.; Bhargava, K. P. Pharmazie 1978, 33, 430.
35. Gray, G. D.; Wickstrom, E. Biotechniques 1996, 21, 780.