Synthesis and biological activity of fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines

Article abstract of DOI:10.1016/j.jfluchem.2015.03.010

New fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines were designed as potential anticancer agents and a practical method for their preparation was developed. The reaction of benzhydrazide with cyanoguanidine followed by intr

Full text of DOI:10.1016/j.jfluchem.2015.03.010

Journal of Fluorine Chemistry 175 (2015) 68–72
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Synthesis and biological activity of fluorinated
7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines§
Anna V. Dolzhenko a, Bee Jen Tan b, Gigi Ngar Chee Chiu b, Wai Keung Chui b,
Anton V. Dolzhenko a,c,
*
a School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia
b Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore
c School of Pharmacy, Curtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia
A R T I C L E I N F O
A B S T R A C T
Article history:
New fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines were designed
as potential anticancer agents and a practical method for their preparation was developed. The reaction
of benzhydrazide with cyanoguanidine followed by intramolecular cyclocondensation resulted in the
formation of triazolylguanidine, which upon condensation with trichloroacetonitrile afforded a key
intermediate – 2-phenyl-7-trichloromethyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amine. In mild condi-
tions, this intermediate underwent nucleophilic displacement of the trichloromethyl group with a series
of fluorinated benzylamines providing the target compounds. Antiproliferative activity of the prepared
compounds against the lung and breast cancer cells was explored. Together with anticancer effect, some
compounds demonstrated anti-angiogenic properties.
Received 24 February 2015
Received in revised form 24 March 2015
Accepted 26 March 2015
Available online 3 April 2015
Keywords:
Triazine
Triazole
5-Azapurine
Amination
ß 2015 Elsevier B.V. All rights reserved.
Anticancer activity
Anti-angiogenic activity
1. Introduction
ment [16–19] and many advancements in the field of anticancer
agents [20,21].
In the drug discovery programs utilizing purine isosteres as
scaffolds, 1,3,5-triazine-based purine analogs are known to possess
a broad range of biological activities [2]. The 5-azapurine (1,2,
4-triazolo[1,5-a][1,3,5]triazine) skeleton [3] has been recognized as
one of the most promising scaffolds among this type of molecules,
particularly for development of new potent bioactive compounds.
Our studies on this heterocyclic system resulted in the development
of a series of practical synthetic methods [4–10] and identification of
several compounds with potent anticancer properties [11]. More-
over, some of the identified compounds were found to inhibit
expression of several angiogenic factors, which are associated with
the tumor growth and metastasis [12–15].
Previously, in our program dedicated to the search of new
antiproliferative agents, we identified fluorinated 1,2,4-tria-
zolo[1,5-a][1,3,5]triazine derivatives 1 (Fig. 1), which were active
against several cancer cell lines [11]. Further development of
structure 1 faced two important medicinal chemistry problems
associated with the dihydro-1,2,4-triazolo[1,5-a][1,3,5]triazine
core structure: (i) existence of the compounds in the form of
racemate due to chirality at C-7 and (ii) potential metabolic
(hydrolytic) instability of the partially saturated dihydrotriazine
ring. The oxidation-aromatization of the heterocyclic system
seemed to be a potential solution for both problems. However,
the aromatization of the structure would significantly change the
geometry of the molecule 1 by eliminating the NH hydrogen bond
donor and by making the fluorinated phenyl ring constrained in the
plane of the 1,2,4-triazolo[1,5-a][1,3,5]triazine system. To over-
come these drawbacks we designed structures 2 (Fig. 1) with the
NH hydrogen donor in close vicinity of the N-6 atom. This
modification aims to retain ability of 2 to interact with the
biological target via a hydrogen bonding pattern, which is similar
to the one proposed for compounds 1. The introduction of the
flexible methylenic bridge should allow the fluorinated phenyl ring
The unique character of fluorinated compounds has been
translated into several successful achievements in drug develop-
§
Part 28 in the series ‘‘Fused heterocyclic systems with an s-triazine ring’’, for
part 27, see [1].
*
Corresponding author at: School of Pharmacy, Monash University Malaysia,
Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia.
Tel.: +60 3 5514 5867; fax: +60 3 5514 6364.
E-mail address: anton.dolzhenko@monash.edu (A.V. Dolzhenko).
http://dx.doi.org/10.1016/j.jfluchem.2015.03.010
0022-1139/ß 2015 Elsevier B.V. All rights reserved.

A.V. Dolzhenko et al. / Journal of Fluorine Chemistry 175 (2015) 68–72
69
substituted benzylamines were used for nucleophilic displacement
of the trichloromethyl group to generate a small library of
fluorinated 1,2,4-triazolo[1,5-a][1,3,5]triazines 2 for biological
screening. The neutral character of the leaving group and
formation of chemically inert and volatile byproduct (chloroform)
as well as mild reaction conditions and straightforward isolation of
the product make this clean and practical procedure a useful tool
for the construction of new bioactive substances.
Fig. 1. Design of fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-
a][1,3,5]triazin-5-amines with potential antiproliferative activity.
The structure of the synthesized compounds was supported by
the NMR spectral data compared with structurally related amino
substituted 1,2,4-triazolo[1,5-a][1,3,5]triazines [5–7,10] and fur-
ther confirmed by X-ray crystallographic study (Fig. 2). The
downfield chemical shift of the benzylamino NH triplet in the 1H
NMR spectra can be attributed to the anisotropic effect of the
heterocyclic ring and indicates a high degree of delocalization of
the electron pair of this exocyclic nitrogen. This geometry
facilitates a potential intramolecular hydrogen bonding of the
NH proton with the triazole ring nitrogen. The molecular structure
of 2c, established using X-ray crystallography data, supported the
NMR spectroscopy findings.
of 2 to enter into the same pocket as the fluorinated phenyl ring of
the prototype 1. To test this hypothesis, a small library of
fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]
triazin-5-amines (2) was synthesized and their antiproliferative
activity against cancer cell lines was explored. In our previous
evaluation of compounds 1, no significant difference in the
biological activity was observed between compounds substituted
with 3- or 4-pyridyl groups [11]. Therefore, we assumed that
removal of the pyridine nitrogen atom can minimize potential
undesirable interaction without altering binding pattern with the
target responsible for the anticipated antiproliferative effect.
Herein, we report synthesis of new fluorinated 1,2,4-tria-
2.2. Biological activity
zolo[1,5-a][1,3,5]triazines
2 and their biological activity viz.
antiproliferative activity against lung cancer A549 and breast
cancer MDA-MB-231 cell lines and anti-angiogenic properties.
The antiproliferative activity of the prepared compounds 2
against lung cancer A549 and breast cancer MDA-MB-231 cell lines
was evaluated in vitro using MTT assay and results were expressed
as IC50 values [25]. The results of the anticancer activity tests are
presented in Table 1. In general, compounds 2 were more active
than their prototypes 1 in the growth inhibition of selected cancer
cell lines. Moreover, despite the fact that the actual target for both
sets of compounds remains unknown, our design appeared to be
reliable. The most active compounds of series 1 and 2 had the same
substitution pattern on the phenyl ring i.e. identical types and
positions of fluorinated groups. Particularly, the highest activity
was observed for 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-
a][1,3,5]triazin-5-amines with 3-fluoro (2b), 3-trifluoromethyl
(2e) and 4-trifluoromethyl (2f) substituents on the benzyl moiety.
In the antiproliferative activity tests against the A549 cell line, the
IC50 value of 2b was lower than that of other compounds in the
series. However, activity of 2b was rather selective and to achieve
an antiproliferative effect against the MDA-MB-231 cell line, 2b
should be applied at higher concentrations than other compounds
reported here.
2. Results and discussion
2.1. Chemistry
The synthesis of the designed compounds 2 was performed
using a practical method based on the introduction of fluorinated
benzylamino moieties by the replacement of a trichloromethyl
group on the electrophilic center [10,22,23].
The reaction of benzhydrazide (3) with cyanoguanidine in the
presence of hydrochloric acid provided N-benzamidobiguanide (4)
(Scheme 1). The biguanide 4 was further cyclized under alkaline
conditions according to the previously reported method [4] to
afford N-(3-phenyl-1,2,4-triazol-5-yl)guanidine (5). Heating gua-
nidine 5 with trichloroacetonitrile in toluene resulted in the
chemo- and regioselective triazine ring closure affording 2-phenyl-
7-trichloromethyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amine (6).
This compound (6) has been recognized as an excellent
building block for the synthesis of 5-azapurine derivatives
[10]. Heating 6 with benzylamines in DMF at 70–80 8C resulted
in the formation of 2 (Scheme 1). The fluorine/trifluoromethyl
It should be noted that at higher concentrations, 2f was
considerably more active than other compounds. The concentra-
tion-response curve for this compound was found to be distinct
Scheme 1. Synthesis of fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines (2a–g).

70
A.V. Dolzhenko et al. / Journal of Fluorine Chemistry 175 (2015) 68–72
Fig. 2. Molecular structure of 7-(4-fluorobenzylamino)-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amine (2c) crystallized with two methanol molecules in the
asymmetric unit [24]. Displacement ellipsoids are drawn at the 50% probability level.
synthesized compounds, together with their IC50 values, the IC90
values were also determined using CalcuSyn 2.0. For the most
active (from the IC50 value prospective) against A549 cells
Table 1
Antiproliferative activity of 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]
triazin-5-amines (2a–g).
compounds (2b, 2e, and 2f), their IC90 values indicated that 2f
Compound
ArF
IC50
,
m
M
could be more than 5 times more effective than 2b and 2e (Table 2).
Moreover, the both type of cancer cells were more responsive to
the treatment with 2f at higher concentrations. Thus, the IC90 value
for 2f against the MDA-MB-231 cell line was 58 ꢀ 6.2 mM.
A549
MDA-MB-231
2a
2b
2c
2d
2e
2f
2-FC6H4
63 ꢀ 8.0
19 ꢀ 5.4
70 ꢀ 10.2
64 ꢀ 19.4
30 ꢀ 10.3
29 ꢀ 6.7
50 ꢀ 11.6
41 ꢀ 0.7
99 ꢀ 21.2
60 ꢀ 3.2
71 ꢀ 13.3
56 ꢀ 9.7
27 ꢀ 6.4
48 ꢀ 11.1
3-FC6H4
4-FC6H4
The evaluation of anti-angiogenenic properties of the synthe-
sized compounds was performed by Eli Lilly and Co. using the tube
formation assay in co-cultured human clonal ECFC cells with
human adipose ADSC cells under the PD2/OIDD scheme [26]. The
compounds with the benzylamino moiety bearing trifluoromethyl
group(s) demonstrated concentration-dependent anti-angiogenic
effect (Table 3). The most active in the antiproliferative experi-
ments against both cancer cell lines used in the study, compound
2f also exhibited highest in the series activity in the anti-
2-CF3C6H4
3-CF3C6H4
4-CF3C6H4
3,5-(CF3)2C6H3
2g
from those of other compounds in this series. This characteristic
behavior of 2f is illustrated in Fig. 3, which compares response of
A549 cells to various concentrations of 2f after 72 h with effects of
2b (lowest IC50 value in the series) and 2e (similar to 2f IC50 value).
The antiproliferetive effect of 2f expanded in relatively narrow
range of concentrations and culminated with a nearly complete
cessation of the cell growth well before a similar effect could be
observed for other active compounds. In order to get a more
meaningful picture of the actual antiproliferative effect of the
angiogenic screening at the concentration 2
mM. However, at
higher concentrations, the most active compound was 2g, which
possessed EC50 value of 9.4
mM in this assay.
Table 2
IC90 values for the most active 7-benzylamino-2-phenyl-1,2,4-triazolo[1,
5-a][1,3,5]triazin-5-amines (2b, 2e and 2f) against A549 cell line.
Compound
ArF
IC90, mM
2b
2e
2f
3-FC6H4
272 ꢀ 14.7
272 ꢀ 93.9
54 ꢀ 6.8
3-CF3C6H4
4-CF3C6H4
Table 3
Anti-angiogenenic activity of trifluoromethyl-substituted 7-benzylamino-2-phe-
nyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines (2d–g) in the anti-angiogenesis
tube formation assay (tube area).
Compound
ArF
Inhibition, %
2
m
M
10 mM
2d
2e
2f
2-CF3C6H4
11
6
28
16
49
55
3-CF3C6H4
Fig. 3. Concentration-dependent antiproliferative effect of the most active
fluorinated 7-benzylamino-2-phenyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines
(2b, 2e and 2f) against A549 lung cancer cells lines after 72 h.
4-CF3C6H4
26
12
2g
3,5-(CF3)2C6H3

A.V. Dolzhenko et al. / Journal of Fluorine Chemistry 175 (2015) 68–72
71
3. Conclusion
1H NMR (300 MHz, Me2SO-d6):
d
4.68 (2H, d, 3J = 6.0 Hz, CH2),
7.02–7.16 (3H, m, NH2 and H-400), 7.22–7.31 (2H, m, H-200 and
4
We successfully designed new anticancer fluorinated 5-azapurine
derivatives via rational structural modifications of the previously
identified series of active compounds. Anticancer and anti-
angiogenic properties of the most active compounds 2f and 2g
make them promising leads for further development of new
anticancer agents.
H-600), 7.38 (1H, td, 3J = 7.8 Hz, JH–F = 6.3 Hz, H-500), 7.46–7.59
(3H, m, H-30, H-40 and H-50), 8.08–8.19 (2H, m, H-20 and H-60), 9.05
(1H, t, 3J = 6.0 Hz, NH).
13C NMR (75 MHz, Me2SO-d6):
d 42.7 (CH2), 113.8 (d,
2JC–F = 21.2 Hz, C-400), 114.2 (d, JC–F = 21.8 Hz, C-200), 123.4
2
4
(d, JC–F = 2.9 Hz, C-600), 126.6 (C-30 and C-50), 128.6 (C-20 and
C-60), 130.0 (C-40), 130.2 (d, 3JC–F = 8.2 Hz, C-500), 130.8 (C-10), 141.4
3
1
(d, JC–F = 7.1 Hz, C-100), 149.1 (C-7), 159.4 (C-2), 162.1 (d, JC–
F = 243.4 Hz, C-300), 162.3 (C-3a), 162.8 (C-5).
4. Experimental
Anal. Calcd. for C17H14FN7: C, 60.89; H, 4.21; N, 29.24%. Found:
C, 60.77; H, 4.30; N, 29.06%.
Melting points (uncorrected) were determined on a Gallen-
kamp melting point apparatus. The reaction progress was
monitored using TLC, which was carried out on aluminum plates
coated with Silica gel 60 F254 (Merck) with detection by UV light.
1H and 13C NMR spectra were recorded on a Bruker DPX-300
spectrometer, using Me2SO-d6 as a solvent and TMS as an internal
reference.
4.2.3. 7-(4-Fluorobenzylamino)-2-phenyl-1,2,4-triazolo[1,5-
a][1,3,5]triazin-5-amine (2c)
Yield = 88%; mp 249–250 8C (EtOH).
1H NMR (300 MHz, Me2SO-d6):
d
4.64 (2H, d, 3J = 6.0 Hz, CH2),
7.08 (2H, s, NH2), 7.17 (2H, dd, 3J = 8.7 Hz, JH–F = 9.0 Hz, H-300
and H-500), 7.47 (2H, dd, 3J = 8.3 Hz, 4JH–F = 5.7 Hz, H-200 and H-600),
7.48–7.57 (3H, m, H-30, H-40 and H-50), 8.07–8.18 (2H, m, H-20 and
H-60), 9.03 (1H, t, 3J = 6.0 Hz, NH).
3
4.1. Synthesis of 2-phenyl-7-trichloromethyl-1,2,
4-triazolo[1,5-a][1,3,5]triazin-5-amine (6)
13C NMR (75 MHz, Me2SO-d6):
d 42.5 (CH2), 115.0 (d,
2JC–F = 21.8 Hz, C-300 and C-500), 126.6 (C-30 and C-50), 128.6 (C-20
and C-60), 129.5 (d, 3JC–F = 8.2 Hz, C-200 and C-600), 130.0 (C-40), 130.7
(C-10), 134.6 (d, 4JC–F = 2.9 Hz, C-100), 149.0 (C-7), 159.4 (C-2), 161.3
Guanidine
5 (4.04 g, 20 mmol) and trichloroacetonitrile
(2.0 mL, 40 mmol) were heated in toluene (50 mL) with stirring
for 7 h. After cooling, the product formed was filtered and
washed with toluene (10 mL) and cold EtOH (10 mL). Yield = 94%,
mp 262–263 8C.
1
(d, JC–F = 242.8 Hz, C-400), 162.3 (C-3a), 162.8 (C-5).
Anal. Calcd. for C17H14FN7: C, 60.89; H, 4.21; N, 29.24%. Found:
C, 60.69; H, 4.40; N, 29.18%.
1H NMR (300 MHz, Me2SO-d6):
d
7.48–7.66 (m, 3H, H-30, H-40
and H-50), 8.09–8.22 (m, 2H, H-20 and H-60), 8.24 (s, 2H, NH2).
13C NMR (75 MHz, Me2SO-d6): 89.2 (CCl3), 127.1 (C-30 and C-
d
4.2.4. 7-(2-Trifluoromethylbenzylamino)-2-phenyl-1,2,
4-triazolo[1,5-a][1,3,5]triazin-5-amine (2d)
Yield = 90%; mp 242–243 8C (EtOH).
50), 128.8 (C-20 and C-60), 129.7 (C-10), 130.9 (C-40), 150.2 (C-7),
160.3 (C-2), 160.7 (C-3a), 164.4 (C-5).
1H NMR (300 MHz, Me2SO-d6):
d
4.90 (2H, d, 3J = 5.7 Hz, CH2),
Anal. Calcd. for C11H7Cl3N6: C, 40.09; H, 2.14; N, 25.50%. Found:
C, 39.85; H, 2.23; N, 25.36%.
7.04 (2H, s, NH2), 7.45–7.57 (4H, m, H-30, H-40, H-50 and H-400), 7.59
3
3
(1H, d, J = 7.5 Hz, H-600), 7.66 (1H, t, J = 7.3 Hz, H-500), 7.76 (1H,
3
d, J = 7.9 Hz, H-300), 8.10–8.21 (2H, m, H-20 and H-60), 9.04 (1H,
4.2. General method for the preparation of 7-benzylamino-2-phenyl-
t, 3J = 5.7 Hz, NH).
1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amines (2a–g)
13C NMR (75 MHz, Me2SO-d6):
d 39.9 (CH2), 124.4 (q,
2
3
1JC–F = 274.0 Hz, CF3), 125.8 (q, JC–F = 30.2 Hz, C-200), 125.8 (q, JC–
2-Phenyl-7-trichloromethyl-1,2,4-triazolo[1,5-a][1,3,5]triazin-
5-amine (6, 0.66 g, 2.0 mmol) was added to a solution of the
appropriate fluorinated benzylamine (2.5 mmol) in DMF (5 mL)
and the mixture was heated at 70–80 8C with stirring for 3 h. After
cooling, ice-cold water (40 mL) was added and the product was
filtered and recrystallized from MeOH or EtOH.
F = 5.9 Hz, C-300), 126.6 (C-30 and C-50), 127.4 (C-400), 127.8 (C-600), 128.6
3
(C-20 and C-60), 130.0 (C-40), 130.8 (C-10), 132.7 (C-500), 136.4 (q, JC–
F = 1.2 Hz, C-100), 149.4 (C-7), 159.4 (C-2), 162.3 (C-3a), 162.9 (C-5).
Anal. Calcd. for C18H14F3N7: C, 56.10; H, 3.66; N, 25.44%. Found:
C, 55.89; H, 3.83; N, 25.34%.
4.2.1. 7-(2-Fluorobenzylamino)-2-phenyl-1,2,4-triazolo[1,5-
a][1,3,5]triazin-5-amine (2a)
4.2.5. 7-(3-Trifluoromethylbenzylamino)-2-phenyl-1,2,4-
triazolo[1,5-a][1,3,5]triazin-5-amine (2e)
Yield = 85%; mp 250–252 8C (EtOH).
Yield = 92%; mp 245–246 8C (MeOH).
1H NMR (300 MHz, Me2SO-d6):
d
4.74 (2H, d, 3J = 5.7 Hz, CH2),
1H NMR (300 MHz, Me2SO-d6):
d
4.77 (2H, d, 3J = 6.0 Hz, CH2),
7.08 (2H, s, NH2), 7.14–7.26 (2H, m, H-300 and H-500), 7.34 (1H, td,
7.12 (2H, s, NH2), 7.46–7.56 (3H, m, H-30, H-40 and H-50), 7.60 (1H, t,
4
3J = 7.9 Hz, JH-F = 5.7 Hz, H-400), 7.42–7.57 (3H, m, H-30, H-40, H-50
3
3J = 7.7 Hz, H-500), 7.66 (1H, d, J = 7.5 Hz, H-400), 7.76 (1H, d,
and H-600), 8.09–8.19 (2H, m, H-20 and H-60), 9.01 (1H, t, 3J = 5.7 Hz,
3J = 7.5 Hz, H-600), 7.80 (1H, s, H-500), 8.10–8.21 (2H, m, H-20 and H-
60), 9.12 (1H, t, 3J = 6.0 Hz, NH).
NH).
13C NMR (75 MHz, Me2SO-d6):
d
37.2 (d, JC–F = 4.7 Hz, CH2),
3
13C NMR (75 MHz, Me2SO-d6):
d
42.9 (CH2), 123.8 (q, JC–
3
115.0 (d, 2JC–F = 21.2 Hz, C-300), 124.3 (d, 4JC–F = 3.5 Hz, C-500), 125.0
(d, 2JC–F = 14.1 Hz, C-100), 126.6 (C-30 and C-50), 128.6 (C-20 and C-60),
3
1
F = 3.7 Hz, C-400), 124.1 (q, JC–F = 3.7 Hz, C-200), 124.2 (q, JC–
F = 272.4 Hz, CF3), 126.7 (C-30 and C-50), 128.6 (C-20 and C-60), 129.0
3
3
2
129.0 (d, JC–F = 8.2 Hz, C-400), 129.2 (d, JC–F = 4.7 Hz, C-600),
(q, JC–F = 31.6 Hz, C-300), 129.4 (C-500), 130.0 (C-40), 130.8 (C-10),
131.7 (q, 4JC–F = 1.2 Hz, C-600), 139.9 (C-100), 149.1 (C-7), 159.4 (C-2),
162.4 (C-3a), 162.9 (C-5).
130.0 (C-40), 130.7 (C-10), 149.2 (C-7), 159.4 (C-2), 159.8
1
(d, JC–F = 244.6 Hz, C-100), 162.3 (C-3a), 162.8 (C-5).
Anal. Calcd. for C17H14FN7: C, 60.89; H, 4.21; N, 29.24%. Found:
C, 60.75; H, 4.23; N, 28.98%.
Anal. Calcd. for C18H14F3N7: C, 56.10; H, 3.66; N, 25.44%. Found:
C, 56.01; H, 3.80; N, 25.25%.
4.2.2. 7-(3-Fluorobenzylamino)-2-phenyl-1,2,
4-triazolo[1,5-a][1,3,5]triazin-5-amine (2b)
Yield = 87%; mp 239–240 8C (MeOH).
4.2.6. 7-(4-Trifluoromethylbenzylamino)-2-phenyl-1,2,
4-triazolo[1,5-a][1,3,5]triazin-5-amine (2f)
Yield = 94%; mp 230–231 8C (MeOH).

72
A.V. Dolzhenko et al. / Journal of Fluorine Chemistry 175 (2015) 68–72
1H NMR (300 MHz, Me2SO-d6):
d
4.75 (2H, d, 3J = 6.2 Hz, CH2),
References
7.07 (2H, s, NH2), 7.46–7.57 (3H, m, H-30, H-40 and H-50), 7.63
(2H, d, 3J = 8.3 Hz, H-200 and H-600), 7.71 (2H, d, 3J = 8.3 Hz, H-300 and
H-500), 8.09–8.18 (2H, m, H-20 and H-60), 9.11 (1H, t, 3J = 6.2 Hz, NH).
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129 (2008) 429–434.
13C NMR (75 MHz, Me2SO-d6):
d
42.8 (CH2), 124.2
1
3
(q, JC–F = 272.1 Hz, CF3), 125.1 (q, JC–F = 3.7 Hz, C-300 and C-500),
2
126.6 (C-30 and C-50), 127.6 (q, JC–F = 31.6 Hz, C-400), 128.0 (C-200
and C-600), 128.6 (C-20 and C-60), 130.0 (C-40), 130.7 (C-10), 143.2
5
(q, JC–F = 1.2 Hz, C-100), 149.1 (C-7), 159.4 (C-2), 162.3 (C-3a),
162.9 (C-5).
Anal. Calcd. for C18H14F3N7: C, 56.10; H, 3.66; N, 25.44%. Found:
C, 55.92; H, 3.76; N, 25.32%.
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34–40.
[14] H. Bera, W.K. Chui, S.D. Gupta, A.V. Dolzhenko, L. Sun, Med. Chem. Res. 22 (2013)
6010–6021.
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67 (2013) 325–334.
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1201–1229.
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Chemistry Research Advances, Nova Science Publishers, Inc, New York, 2007,
pp. 105–142.
[18] J.P. Be´gue´, D. Bonnet-Delpon, Bioorganic and Medicinal Chemistry of Fluorine,
Wiley, New York, NY, 2008.
[19] I. Ojima, Fluorine in Medicinal Chemistry and Chemical Biology, Blackwell,
Oxford, 2009.
4.2.7. 7-[3,5-bis-(Trifluoromethyl)benzylamino]-2-phenyl-1,2,
4-triazolo[1,5-a][1,3,5]triazin-5-amine (2g)
Yield = 93%; mp 261–262 8C (MeOH).
1H NMR (300 MHz, Me2SO-d6):
d
4.84 (2H, d, 3J = 6.0 Hz, CH2),
7.10 (2H, s, NH2), 7.46–7.58 (3H, m, H-30, H-40 and H-50), 8.03 (1H, s,
H-400), 8.09–8.20 (4H, m, H-20, H-60, H-200 and H-600), 9.11 (1H, t,
3J = 6.0 Hz, NH).
13C NMR (75 MHz, Me2SO-d6):
d 42.6 (CH2), 120.9 (m,
1
3JC–F = 3.2 Hz, C-400), 123.3 (q, JC–F = 272.8 Hz, 2CF3), 126.6 (C-30
3
and C-50), 128.5 (q, JC–F = 4.3 Hz, C-200 and C-600), 128.6 (C-20 and
2
C-60), 130.0 (C-40), 130.1 (q, JC–F = 32.7 Hz, C-300 and C-500), 130.8
(C-10), 141.9 (C-100), 149.1 (C-7), 159.4 (C-2), 162.3 (C-3a),
162.9 (C-5).
[20] X. Yang, A. Guan, J. Fluor. Chem. 161 (2014) 1–10.
[21] J. Seitz, J.G. Vineberg, E.S. Zuniga, I. Ojima, J. Fluor. Chem. 152 (2013) 157–165.
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(2011) o1183–o1184.
Anal. Calcd. for C19H13F6N7: C, 50.34; H, 2.89; N, 21.63%. Found:
C, 50.18; H, 2.74; N, 21.45%.
Acknowledgement
[25] M.C. Alley, D.A. Scudiero, A. Monks, M.L. Hursey, M.J. Czerwinski, D.L. Fine, B.J.
Abbott, J.G. Mayo, R.H. Shoemaker, M.R. Boyd, Cancer Res. 48 (1988) 589–601.
[26] J.A. Lee, S. Chu, F.S. Willard, K.L. Cox, R.J. Sells Gavin, R.B. Peery, S.E. Oliver, J. Oler,
T.D. Meredith, S.A. Heidler, W.H. Gough, S. Husain, A.D. Palkowitz, C.M. Moxham,
J. Biomol Screen. 16 (2011) 588–602.
The authors are grateful for the OIDD screening data supplied
courtesy of Eli Lilly and Company, which are reported with
permission.