Synthesis, Spectroscopic Studies of Fluorinated Pyrimido-1,2,4-Triazines: Protective Effect Against Some Plant Pathogenic Fungi

Article abstract of DOI:10.1002/jhet.2386

In search for new biologically active compounds, several new fluorine-substituted pyrimido [2,3-c][1,2,4]triazino (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) have been synthesized via the nucleophilic attack of 2-hydrazinopyrimidinone (2) toward more positive carbons under different conditions. Structure of the newly synthesized compounds was deduced from elemental analyses as well as their spectral data (UV, IR, NMR, and M/S). The antifungal activity of the target ring systems has been evaluated both in vitro and in vivo against some phytopathogenic fungi associated with wheat grains. Result showed that compounds 6, 7, and 8 have high protection of wheat grains against the fungal infection.

Full text of DOI:10.1002/jhet.2386

Month 2015 Synthesis, Spectroscopic Studies of Fluorinated Pyrimido-1,2,4-Triazines:
Protective Effect Against Some Plant Pathogenic Fungi
*
Faisal M. S. Aqlan, Mohammed S. T. Makki, and Rada M. Abdel-Rahman
Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
*
E-mail: aqlanfaisal@gmail.com
Received June 4, 2014
DOI 10.1002/jhet.2386
Published online 00 March 2015 in Wiley Online Library (wileyonlinelibrary.com).
In search for new biologically active compounds, several new fluorine-substituted pyrimido [2,3-c][1,2,4]
triazino (3–16) have been synthesized via the nucleophilic attack of 2-hydrazinopyrimidinone (2) toward
more positive carbons under different conditions. Structure of the newly synthesized compounds was de-
duced from elemental analyses as well as their spectral data (UV, IR, NMR, and M/S). The antifungal activ-
ity of the target ring systems has been evaluated both in vitro and in vivo against some phytopathogenic fungi
associated with wheat grains. Result showed that compounds 6, 7, and 8 have high protection of wheat grains
against the fungal infection.
J. Heterocyclic Chem., 00, 00 (2015).
INTRODUCTION
distribution in the molecule, affecting its absorption, distri-
bution, and metabolism [20,21].
The treatment of infectious diseases remains an important
and challenging problem because of a combination of fac-
tors including the discovery of new infectious microorgan-
isms and the increasing number of multi-drug resistant
microbial pathogens. Therefore, there is real perceived need
for the discovery of new compounds endowed with biocidal
and/or enzymatic activity. Pyrimidines continue to receive
much attention in recent years due to their unique physical,
chemical, and pharmacological applications as potential mi-
crobial growth inhibitors [1–3], photochemical probe agents
[4], and biocidal agents [5]. A variety of nitrogen-bridged
pyrimidines was reported to be used as multi-targeted small
molecule inhibitors and resistance-modifying agents [6–11].
On the other hand, 1,2,4-triazines and their condensed
hetrobicyclic ring systems have attracted considerable inter-
est in recent years as anti-HIV [12], antifungal agents
[13,14], molluscicidal agents [15], and antitumor agents
[16]. Furthermore, several triazine derivatives have been
known to display a wide spectrum of medical and pharma-
cological activities [17,18]. In addition, some 1,2,4-triazine
derivatives have shown an interesting activity as plant pro-
tection agents [19]. On the other hand, introduction of fluo-
rine atoms into bioactive molecules often improves and
enhances their medicinal, pharmacological, and biological
activities, mainly because of the enhanced hydrophobicity,
increase in membrane permeability, and increased stability
against metabolic transformation. Moreover, the very high
electronegativity of fluorine atom can modify the electronic
In view of these observations, this work is devoted to the
synthesis of fluorinated hybrid molecules containing both
the pyrimidine and 1,2,4-triazine nuclei in one structure en-
tity, namely, pyrimido[2,3-c][1,2,4]triazino hoping to get
potential biologically active compounds as plant protecting
agents against fungal infections.
RESULTS AND DISCUSSION
Chemistry. The starting material 4-(4-fluorophenyl)-
2-hydrazinyl-6-oxo-1,6-dihydropyrimidine-5-carbonitrile
2 was obtained from refluxing the corresponding 2-
mercapto derivatives 1 with hydrazine hydrate in ethanol
(Scheme 1).
Structures of 1 and 2 were deduced from their IR and
1HNMR spectra. IR spectra of 1 showed the presence of
NH, CN, C¼O, and S–H functional groups at λ 3437,
2232, 1702, and 1161 cmꢀ1, whereas that of 2 recorded a
lack of SH functional groups, with present of NH2, NH at
1
λ 3400–3199 cmꢀ1. HNMR spectra of 1 showed a signal
at δ 4.95–4.93 and 8.0 ppm for SH and NH protons
(Fig. 1).
Cyclocondensation of 2-hydraziano pyrimidinone 2 with a
1,2-bicarbonyl compounds as sodium pyruvate (in aqueous so-
dium hydroxide) or diethyl oxalate (in THF) [22] afforded
8-(4′-fluorophenyl)-7-cyano-3-methylpyrimido[3,4-c][1,2,4]tri-
azine-4,6-dione 3 and/or 8-(4′-fluorophenyl)-7-cyano-1,2,3,4-
© 2015 HeteroCorporation

F. M. S. Aqlan, M. S. T. Makki, and R. M. Abdel-Rahman
Vol 000
Scheme 1. Synthesis of compounds 1–6.
various isomeric structural formulae. 1H-NMR of com-
pounds 6a,b showed δ 8.16–7.97ppm for 2H, coupling of
aryl protons with the styryl moiety. In addition, the IR spectra
recorded the presence of C–Cl, C–Br, and C–F at λ 756, 779,
and 1250cmꢀ1, whereas the MS of 6a showed m/z at 420
with a base peak at 95 (Fig. 2).
In Scheme 2, compound 2 reacted with isatin under dif-
ferent reaction conditions (either in NaOH or DMF) [24],
where 8-(4′-fluorophenyl-7-cyano-3-(2׳-aminophenyl)-1H-
pyrimido[3,2–c][1,2,4]triazine-4,6-dione 7 and 11-(4′-fluo-
rophenyl-10-cyano-1H-pyrimido[3,2–c][1,2,4,]triazine[6,5-b]
indole 10 were obtained, respectively. Chemical reactivity of
compound 7 was evaluated by fluoroacetylation of the NH2
group with trifluoroacetic anhydride in boiling THF,
where the 1-(2′-trifluoroacetyl)-3-(2′-trifluoroacetyl)-
3-(2׳-trifluoroacetyl-aminophenyl)pyrimido[3,2-c][1,2,4]
triazine-4,6-dione 8 was produced. Analogously, treat-
ment of 7 with 4-fluorobenzoyl chloride in warm DMF re-
sulted in the formation of the corresponding 4-fluoroanilido
derivative 9. The IR of 8 showed the presence of absorption
bands of both NH2 and two carbonyl groups at λ 3200,
1700, 1626 cm ꢀ1, respectively. The mass spectrum of
compound 10 exhibited the molecular ion peak at m/z
356 with a base peak at m/z 95 (C6H4F) (Fig. 3).
Figure 1. Mass fragmentation pattern of compound.
tetrahydropyrimido[3,2–c][1, 2, 4]triazine-3,4,6-trione 4, re-
spectively (Scheme 2). The IR of 3 showed λ at 1735 and
1678cmꢀ1 attributed to two carbonyl groups, whereas com-
pound 4 recorded λ at 1670 and 1610cmꢀ1 for carbonyl and
amide functions, respectively. The 13C-NMR of compound 3
exhibited signals at δ 169.82 and 165.24ppm for two C¼O,
whereas its MS recorded the molecular ion peak at m/z 298 with
a base peak at m/z 95. An interesting result was obtained by the
cycloaddition of 2-hydrazinopyrimidinone 2 with (E) 4-aryl-2-
oxo-but-3-enoic acid 5 in refluxing sodium hydroxide solution
[23], where 8-(4′-fluorophenyl-7-cyano-3-styryl-1H-pyrimido
[3,2–c][1,2,4]triazine-4,6-diones 6a,b were produced instead
of the 5-(4-substitutedphenyl)-1-(5-cyano-4-(4-fluorophenyl)-
6-oxo-1,6-dihydropyrimidin-2-yl)-4,5-dihydro-1H-pyrazole-3-
carboxylic acids (Scheme 1). Compounds 6a,b did not give
acidity test with bicarbonate solution, instead, they showed
Regarding Scheme 3, regioselective heterocyclization of
he starting 2-hydrazino-pyrimidinone 2 as a nucleophile
with different α-active electrophilic reagents as mono-
chloroacetic acid in refluxing aqueous NaOH produced
8-(4′-fluorophenyl-7-cyano-1,2,3,4–tetrahydropyrimido
Journal of Heterocyclic Chemistry
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Month 2015
Synthesis of Fluorinated Pyrimido-1,2,4-Triazines
Scheme 2. Synthesis of compounds 7–10.
Figure 2. Mass fragmentation pattern of compound 6a.
[3,2-c][1,2,4] triazine-4,6-dione 11, whereas treatment of
2 with chloroacetyl chloride in warm DMF (accelerated
SN2 reaction) [20] yielded the isomeric structure 12.
Structures of 11 and 12 were confirmed from their UV,
IR, and NMR spectra. The IR of compounds 11 and 12 re-
corded the presence of NH–NH and CH2 as well as two
carbonyl groups at λ 3366, 3152, 2890, 1668, and
1639 cmꢀ1, respectively. The UV of 10 recorded a λmax
at 373 nm attributed to n–π* and π–π* electronic transi-
tion. 13C-NMR of 11 recorded δ at 170, 161 ppm for
C¼O and CONH carbons, whereas 1H-NMR of 12
showed signals at δ ppm 12.32, 11.43 of two NH and
3.68 for CH2 protons.
In their turn, compounds 11 and 12 were subjected to
Kneogeval condensation with 4-chlorobenzaldehyde in
refluxing ethanol using piperidine as a catalyst to produce
the arylidene derivatives 13 and 14, respectively (Scheme 3).
The UV absorption of these compounds gave a good indica-
tion about their skeletons, where λmax of 13 is higher than
14, which is attributed to the aromatic stabilization of the
heterocyclic system. On the other hand, oxidation of the
pyrimidothiazinones 11 and 12 using Fe2(SO4) in warm
methanol yielded the corresponding oxidized products 15
and 16, respectively. The prevalence of the aromatic pheno-
lic form was chemically deduced by giving a positive test
with neutral FeCl3. The UV absorption spectrum of 15 re-
corded λmax at 378nm, whereas the IR spectra for both 15
and 16 exhibited λ at 2220, 1280, and 1250cmꢀ1 attributed
to CN, C¼O, and C–F functions, respectively, in addition to
the absorption bands at λ 3450cmꢀ1 for OH in 15 and at
3470cmꢀ1 for 16.
Biological activity. Plant protection and antifungal activity. It
has been reported that several pyrimidinones are inhibitors
of Zeta-carotene desaturase [25] and possess interesting
herbicidal activity [26]. Recently, Abdel-Rahman et al.
reported that some pyrimidopyrimidines acted as multi-
targeted small molecule inhibitors and resistance-
modifying agents. On the other hand, the NCNN group
Journal of Heterocyclic Chemistry
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F. M. S. Aqlan, M. S. T. Makki, and R. M. Abdel-Rahman
Vol 000
Figure 3. Mass fragmentation pattern of compound 10.
Scheme 3. Synthesis of compounds 11–16.
proved to be an essential part of various heterocycles
bearing high biological activities [27,28]. In addition,
1,2,4-triazines and their fused derivatives have found
applications as herbicides [29], amylolytic agent for
fungi [30], and plant protection agents [31]. Therefore, it
was of interest to evaluate the antifungal activity of the
target compounds both in vitro and in vivo against some
phytopathogenic fungi associated with wheat grains.
alterata, Helimenthosporium sativum, and Fusarium
moniliforme. DMF was used to make the desired
concentrations, and sterile potato dextrose agar cultures
were used. The culture plates were inoculated with a 4-
mm diameter disc of inoculum of each fungus removed
from a 7-day-old culture. Fungitoxicity was expressed as
toxicity index depending on the ED50 values [32,33]
(Table 1).
In vitro antifungal activity.
The in vitro antifungal
In vivo fungal activity.
The in vivo fungal toxicity
activity of the new compounds was evaluated by
inhibition of fungal mycelial growth of Alternaria
activity of the compounds was tested on A. alterata and
F. moniliforme fungi. Discs of orange rinds (3 × 3 cm)
Journal of Heterocyclic Chemistry
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Month 2015
Synthesis of Fluorinated Pyrimido-1,2,4-Triazines
Table 1
Antifungal activity toxicity index.
Table 3
Germination percent of wheat grains treated the tested compounds and
planted in soil infested with some fungi.
Comp.
no.
Alternaria
alterata
Helimenthosporium
sativum
Fusarium
moniliforme
% Germination in soil infested with
1
3
4
6a
6b
7
4
5
2
5
4
5
1
3
2
2
3
2
0
5
5
0
0
3
1
0
2
0
4
5
5
0
0
0
1
1
Comp.
no.
Concentration
Alternaria
alterata
Fusarium
moniliforme
μg/mL
1
500
1000
500
1000
500
1000
500
1000
500
1000
500
1000
500
1000
500
1000
500
50.00
53.15
43.16
47.25
27.25
38.50
63.50
80.15
26.55
38.13
57.00
68.00
55.52
70.00
42.50
40.11
50.00
51.85
40.85
41.25
28.75
28.00
31.26
46.00
58.25
26.25
30.00
79.5
3
8
11
12
13
4
6a
6b
7
89.5
Estimated ED50 for inhibition of mycelia growth.
28.50
31.00
52.51
54.61
56.00
58.66
28.00
30.00
28.00
30.00
63.55
75.75
30.00
were removed from sound novel orange fruits. The discs
were surface sterilized by immersing 70% ethanol, the
rinds were treated with the tested compounds by dipping.
The treated discs were allowed to dry and were artificially
inoculated with spores of tested fungi, commercial
thiobendazol-2-(4-thiazolyl)benzimidazol was used as
control. All treatments were replicated three times, and all
the discs were stored in petri dishes containing a wet cotton
plug to ensure a high relative humidity. After 1week, the
percentage of rotted discs was evaluated (Table 2).
8
11
12
13
*TBZ
1000
500
1000
500
*Commercial thiobendazol-2-(4-thiazolyl)benzimidazole (TBZ) was used
as reference standard.
From the results obtained in (Table 2), F. moniliforme is
more sensitive to the tested compounds followed by H.
sativum and A. alterata. Compounds 6a, 6b, and 8 exhib-
ited a high fungal toxicity activity. On the other hand, com-
pound 7 is more toxic than the other tested compounds. It
is interesting that compounds 11–13 showed a total loss
of activity.
concentration of 1000 μg/mLꢀ1 against F. moniliforme. Fi-
nally, the best germination (80–90%) was achieved by
treating the seeds with a solution containing 1000 μg/mL
of compound 6a followed by compound 8 under the same
concentration (59–70% germination) (Table 3).
In the prevention of blue mold development [34], the ac-
tion of the tested compounds on the decay control on rind
discs is presented in Table 3. The results indicate that only
compounds 3 and 6b gave a good control at a concentra-
tion of 500 μg/mLꢀ1 against A. alterata, whereas com-
pounds 1, 6b, 11, and 12 gave a good control at a
CONCLUSION
In conclusion, compounds 6a, 6b, 7, and 8 can be used
as plant protective against fungal toxicities A. alterata
and F. moniliforme by inhibition of mycelia growth com-
pared with thiobendazol-2-(4-thiazolyl)benzimidazol as
control. Also, compounds 6a and 8 exhibited a higher ger-
mination percentage, whereas compounds 1, 6a, 11, and 12
gave a good control at higher concentration. Thus, these
compounds can be used as plant growth regulators.
Table 2
ED50 (μg/mL) values of some fluorinated pyrimido-1,2,4-triazines.
Comp.
no.
Alternaria
alterata
Helimenthosporium
sativum
Fusarium
moniliforme
1
3
4
6a
6b
7
80.8
250.5
166.2
7.2
110.3
280.3
200.0
8.3
310.0
320.0
390.5
11.2
EXPERIMENTAL
Melting points were determined with an electro thermal bib by
Stuart Scientific Melting Point SMPI (UK). The IR spectra re-
corded for KBr discs were recorded on Perkins Lemer Spectrum
29.5
18.5
13.5
169.0
150.5
1000.0
1000.0
1000.0
18.105
140.5
1000.0
1000.0
1000.0
220.5
220.05
1000.0
1000.0
1000.0
1
8
RXI-FT-IR system 55529 (USA). H-NMR spectra were deter-
11
12
13
mined for solution in deuterated (DMSO) with a Brucker NMR
Advance DPX 400 MH (Germany) using TMS as an internal
standard. Mass spectra were measured on a GCMS-Q 1000-Ex.
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F. M. S. Aqlan, M. S. T. Makki, and R. M. Abdel-Rahman
Vol 000
Spectrometer (Germany). Electronic absorption spectra were re-
corded on Shimadzu UV and visible 3101 PC spectrophotometer
(Kyoto, Japan). Elemental analysis determination was performed
in Microanalytical Center Cairo University-Egypt. 19F-NMR
spectra were recorded by using hexafluorobenzene, and the
aromatic C–F exhibited at ꢀ122 to ꢀ124 ppm. Compound 5
was prepared according the reported method [35].
8-(4′-Fluorophenyl)-7-cyano-1,2-dihydro-pyrimido[3,2-c]
[1,2,4]triazin-3,4,6-trione (4). A mixture of 2 (0.01 mol)
and sodium pyruvate (0.01 mol) in THF (50 mL) was refluxed
for 4 h and then cooled. The solid product was filtered and crys-
tallized from dioxan to give 4 as yellowish crystals, mp 278–
280°C, yield 65%; IR (ʋcꢀm1): 3250–3143 (b, NH–NH), 2210
(C≡N), 1670, 1610 (C¼O,–CONH), 1588 (C¼N), 1392 (NCN),
1
4-(4′-Fluorophenyl)-5-cyano-2-mercapto-3H-pyrionidin-6-one (1).
Equimolar mixture of 4-Fluorobenzaldehyde and ethyl 2-
cyanoethanoate was refluxed with thiourea (1:1 mmole) in so-
dium ethoxide, then stirred for 2 h and left over night to give
the targets product 1 [22] by a high yield of 85% and crystallized
from ethanol to give 1 as orange crystals. mp 209–210°C; IR (λ
cmꢀ1) 3437 (NH), 3081 (Ar–CH), 2232 (C≡N), 1702 (C¼O),
1552 (C¼N), 386 (CN–C), 1250 (C–F), 1161 (C¼S), 842
(P-substituted phenyl), 674 (C–F); 1H-NMR (δ ppm): 8.00
(τ, 1H, NH), 7.75–7.73, 7.45–7.35, 7.24–7.21, 7.145–7.104
(each s, 4H, aromatic CH), 4.95–4.93, (s, 1H, SH); 13C-NMR
(δ ppm): 179.74 (C¼S), 176.50 (C¼O), 159.63–158.92 (C–F),
131.31–131.25, 130.38–130.75, 129.23–129.17, 128.95–128.89,
125.09–125.07 (aromatic carbons), 116.33–116.95 (C N), 115.59,
114.15 (C¼N), 113.35 (CN), 90.62 (NCN), 77.67, 77.46, 77.25
(5,6–C¼C of pyrimidine); Anal. Calcd. C, 53.44; H, 2.42;
N, 17.00; S, 12.95; F, 7.96% for C11H6N3FSO (247). Found:
C, 53.00; H, 2.30; N, 16.63; S, 12.69; F, 7.33%.
1239 (C–F), 837,811 (P-substituted ring), 659 (C–F); H-NMR (δ
ppm): 12.38, 12.14 (each s, 2H, NH, NH of 1,2,3-triazine), 8.17,
8.6, 8.01, 7.96, (each s, 4H of aryl, 7.19, 7.11 (coupling, doubled,
doubled of F on CH protons); 13C-NMR (δ ppm) = 169.61, 164.52,
163.11, 162.82, 161.80, 153.39, 146.20, 132.48, 130.72, 116.87–
115.06, 86.37, 78.56–78.12. Anal. Calcd. C, 52.17; H, 2.06; N,
23.41; F, 6.35% for C13H6N5FO3 (299). Found: C, 51.89; H, 1.88;
N, 23.11; F, 6.20%.
8-(4′-Fluorophenyl)-7-cyano-3-styryl-pyrimido[3,2-c][1,2,4]
triazin-4,6-diones (6a,b). A mixture of 2 (0.01 mol) and com-
pound 5a and/or 5b [35] (0.01 mol) in NaOH (5%, 100 mL) was
refluxed for 2 h then cooled and poured into ice HCl. The yielded
solid was filtered and crystallized from THF to give 6a and/or
6b, respectively, as yellow crystals, 6a yield 70%; mp 170–172°C;
6a: UV (ʎmax nm) = 375; IR (ʋꢀcm1): 3180 (NH), 3080 (aromatic
CH), 2923 (aliphatic CH), 2217 (C≡N), 1680, 1660 (2C¼O), 1615
(C¼C), 1586 (C¼N), 1485 (deformation, CH¼CH), 1384 (NCN),
1252 (C–F), 827, 815 (P-substituted ring), 756 (C–Cl), 680 (C–F);
1H-NMR (δ ppm): 8.62–8.55 (d, 1H, NH), 8.16–7.97 (each s, 2H,
coupling of aryl protons with –CH¼CH– protons); 7.95–7.90, 7.89–
7.74, 7.73–7.68, 7.60–7.58, 7.57 7.53, 7.18–7.16, 7.12–7.09, 6.73–
6.67 (each s, 8H, aromatic protons); 13C-NMR (δ ppm) = 167.42
(C¼O), 153.29 (C–F), 146.53 (C–C),131.94, 131.92, 131.69,
131.41, 131.32, 130.83, 130.78, 130.56, 130.49, 130.42, 129.96,
129.88 (12 aromatic carbons), 127.36 (CN) (115.98–115.95,
115.83–115.81 (C¼N), 115.59, 115.38, 115.19 (C–N), 111.53,
111.46 (CH¼CH), 77.82–77.39 (NCN); M/S (Int%) = 420 (10.95),
392 (5.11), 364 (8.13), 336 (6.01), 198 (18.23), 297 (25.13), 160
(37.11), 137 (3.15), 95 (100), 111 (78.77), 66 (15.00); Anal. Calcd.
C, 60.14; H, 2.62; N, 16.70; F, 4.53, Cl, 8.35% for C21H11N5FClO2
(419). Found: C, 60.01; H, 2.55; N, 16.49; F, 4.29; Cl, 8.21%.
1H-2-hydrazino-4-aryl-5-cyano pyrimidin-6-one (2). Equi-
molar mixture of compound 1 (0.01 mol) and hydrazine hydrate
(0.01 mol) was refluxed in ethanol (20 mL) for 6 h then cooled.
The resulted solid was filtered and crystallized from EtOH to
give 2 as deep yellow crystals. UV (λ
nm) 358.4; IR (λ
max
cmꢀ1): 3400–3100 (b, NH, NH2), 3067 (aromatic CH), 2228
(C≡N), 1667 (C¼O), 1601 (deformation NH2), 1551 (C¼N),
1295 (C–N), 1245 (C–F), 830 (P-Substituted ring), 776 (C–F);
1H-NMR (δ ppm): 8.62 (s, 1H, NH), 7.98–7.85, 7.75–7.65,
7.26–7.16, 7.16–7.022, (2H, 2H of aromatic protons), 3.61 (s,
2H, NH2); 13C-NMR (δ ppm): 176.43 (C¼O), 160–158 (C–F),
131.32–131.26, 130.48–130.42, 130.23–130.21, 125.10 (six car-
bons of aryl pyridine), 115.93–115.79 (C≡N), 114.18 (C¼N), 90.52
(N–C–N), 78.07, 77.85, 77.64 (4,5–CH¼CH of pyrimidine); M+/S
(Int.%): 245 (246, M + 1, 13%), 214 (8.15), 148 (3.00), 95 (100),
52 (75); Anal. Calcd. C, 53.87; H, 3.26; N, 28.57; F, 7.75% for
C11H8FN5O (245). Found: C, 53.51; H, 3.00; N, 28.33; F, 7.45%.
6b, yield 65%; mp 128–130°C; IR (ʋꢀcm1) = 3190 (NH), 3080
(aromatic CH), 2923, 2880 (aliphatic CH), 2099 (CN), 1680,
1676 (2C¼O), 1584 (C¼N), 1484, 1424 (deformation CH¼CH),
1399 (NCN), 1259 (C–F), 928, 884, 808 (P-substituted ring), 756,
1
679 (C–Br, C–F); H-NMR (δ ppm) = 9.973 (s, 1H, NH), 8.62–
8-(4′-Fluorophenyl)-7-cyano-3-methyl-pyrimido[3,2-c][1,2,4-
8.59 (each m, 2H, coupling CH¼CH– with aryl protons), 7.96–
7.95, 7.86–7.853, 7.851–7.842, 7.80–7.78, 7.44–7.43, 7.16–
7.14, 6.73–6.69 (each s, 8H, aromatic protons), 3.69–3.68 (s,
1H, ,B CH¼) 3.69–3.68 (s, 1H, α, CH =), 3.09–3.05 (s, 1H, β–
CH¼); 13C-NMR (δ ppm) = 160.93 (C¼O), 160.71 (C¼O),
137.04 (C–F), 132.48–132.41 (C–Br), 130.91–130.86, 130.60–
130.54, 130.48, 130.25–130.23, 130.95–130.174, 129.739–
129.687, 129.734, 129.06–129.05, 128.93–128.59 (12 aromatic
carbons), 116.04, 116.02 (CN), 115.90–115.88 (α CH¼),
115.44–115.30 (β–CH¼), 111.59 (CN); Anal. Calcd. C, 54.31;
H, 2.37; N, 16.50; F, 4.09, Br, 17.24% for C21H11N5FBrO2
(464). Found: C, 54.02; H, 2.15; N, 16.35; F, 3.85; Br, 17.01%.
8-(4′-Fluorophenyl)-7-cyano-1H-3-(2′-aminophenyl)pyrimido
[3,2-c][1,2,4]triazin-4,6-dione (7). A mixture of 2 (0.01 mol)
and isatin (0.01 mol) in NaOH (5%, 100 mL) was refluxed for
2 h then cooled and poured into ice HCl. The yielded solid
was filtered and crystallized from EtOH to give 7 as yellowish
crystals, mp 277–279°C, yield 75%.
]triazin-4,6-dione (3).
Equal amounts of 2 and diethyl oxalate
(1:1 mmole) were refluxed with NaOH (2%, 100 mL) for 4 h then
cooled and poured into ice HCl. The yielded solid was filtered
and crystallized from EtOH to give 3 as yellowish crystals, mp
244–246°C, yield 68%; IR (ʋꢀcm1) = 3128 (NH), 3080 (aromatic
CH), 2937 (aliphatic CH), 2229 (C≡N) ,1735 (C¼O), 1678 (C¼O),
1587 (C¼N), 1485 (deformation, CH3), 1372 (cyclic NCN),
1252 (C–F), 847 (aromatic C¼C), 664 (C–F); 1H-NMR (δ ppm)=
12.87 (s, 1H, NH), 8.008–8.006, 7.993–7.981, 7.473–7.41,
7.193–7.167 (each s, 4H, aromatic protons), 2.258 (s, 3H, CH3);
13C-NMR (δ ppm) = 169.82 (C¼O), 165.24–164.60 (C¼O),
153 (C–F), 143.79, 132.01, 131.02, 130.96, 116.17,115.48 (aro-
matic carbons), 115.33 (C≡N), 89.71 (NCN), 77.69–
77.67,77.46–77.24 (C¼C of pyrimidine), 12.453 (CH3); M/S
(Int%) = 297 (298, M+1, 13.11%), 269 (8.11), 241 (28.15), 187
(21.0), 95 (100), 92 (35.18); Anal. Calcd. C, 56.56; H, 2.69; N,
23.56; F, 6.39% for C14H8N5FO2 (297). Found: C, 56.33; H,
2.39; N, 23.11; F, 6.21%).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2015
Synthesis of Fluorinated Pyrimido-1,2,4-Triazines
UV (ʎmax nm) = 370; IR (ʋꢀcm1) = 3199 (NH), 2224 (C≡N),
1680, 1660 (2C¼O), 1621 (deformation NH2), 1607, 1541
(C¼N), 1384 (NCN), 1237 (C–F), 893, 843, 815, 785 (O,P-substituted
ring), 656 (C–F); 1H-NMR (δ ppm) = 10.70 (s, 1H, NH), 7.55, 7.67–
7.61, 7.34–7.31, 7.21–7.208, 7.202–7.197, 7.095–7.077, 6.967–6.90
(each m, 7H, aromatic), 6.89–6.88 (s, 1H, NH of NH2), 3.677–3.651
(s, 2H, NH2); 13C-NMR (δ ppm) = 164.23 (C¼O), 145.16–145.14
(C–F), 133 (C–NH2), 128.76–122.5 (aromatic carbons), 116 (NCN),
111–113 (CN), 78.09–77.666 (carbons of 1,2, 4-triazine), 66 (C¼N);
Anal. Calcd. C, 60.96; H, 2.94; N, 22.24; F, 5.08% for C19H11N6FO2
(374). Found: C, 60.59; H, 2.88; N, 22.05; F, 4.95%.
Trifluoroacetyl-3-(trifluoroacetyl amino phenyl-8-4-fluoro-phe-
nyl-7-cyano-pyrimido-[3,2-c][1,2,4] triazin-4,6-dione (8). A mix-
ture of compound 7 (0.285 g and trifluoroacetic anhydride (2 mL) in
THF (20 mL) was reflux for 24 h and cooled. The resulted solid filtered
off and crystallized from dioxan to give 8 as yellowish crystals, yield
70%; mp 239–240°C; IR (ʋcꢀm1): 3200 (NH2), 2215 (C≡N), 1700,
1626 (C¼O), 1598 (CONH), 1585 (C¼N), 1316 (NCN), 1295, 1224
(C–F), 805, 825 (O,P-substituted ring), 707 (C–F); 1H-NMR (δ
ppm): 12.8, 10.8 (each s, NH↔OH), 7.88–6.77 (m, 8H, aryl protons);
13C-NMR (δ ppm) = 184.50, 159.40, 145.08, 138.33, 128.58, 128.32,
124.79, 122.87, 120.71, 115.95–111.06, 78.51; Anal. Calcd. C,
49.64; H, 1.61; N, 23.92; F, 15.10 for C23H9N6F7O4 (556). Found:
C, 49.39; H, 1.51; N, 23.55; F, 14.88%.
132.15, 130.86–130.81, 130.04–129.71, 129.23, 129.15–129.07,
129–016–129.91 (6C aromatic), 116 (C≡N), 115.78, 115.23
(C¼N), 87.24 (C–N), 77.83, 77.62, 77.40 (carbons of 1,2,4-
triazine), 40.14–39.58 (aliphatic carbons); Anal. Calcd. C,
54.73; H, 2.2.80; N, 24.56; F, 6.69%. For C13H8N5FO2 (285).
Found: C, 54.55; H, 2.39; N, 24.28; F 6.51%.
8-(4′-Fluorophenyl)-7-cyano-1,2,3,4-tetrahydro-pyrimido[3,2-
c][1,2,4]triazin-3,6-dione (12).
A mixture of 2 (0.01 mol) and
chloroacetyl chloride (0.01 mol) in DMF (100 mL) was warmed for
1 h then cooled. The obtained solid was filtered and crystallized from
dioxan to give 12 as faint yellow crystals, yield 60%; mp 254–255°C;
UV (ʎmax nm): 351; IR (ʋꢀcm1): 3400–3200 (b, OH, NH–NH), 2210
(C≡N), 1668 (C¼O), 1591 (C¼N), 1494, 1410 (deformation CH2),
1392 (NCN), 1254 (C–F), 857, 815, 786 (P-substituted ring), 658
(C–F); 1H-NMR (δ ppm) = 12.32 (s, 1H, NH, 1,2,4-triazine), 11.43
(s, 1H, NH, 1,2,4-triazine), 8.61–8.55, 7.96–7.90, 7.85–7.51, 7.48–
7.37, 7.18–7.098 (each s, aromatic protons), 3.68–3.66 (m, 2H,
CH2), 2.900–2.58 (each s, 2H, N–CH2–COH); Anal. Calcd. C,
54.73; H, 2.80; N, 24.56; F, 6.69% for C13H8N5FO2 (285). Found:
C, 54.33; H, 2.51; N, 24.13; F, 6.48%.
8-(4′-Fluorophenyl)-3-arylidene-7-cyano-1,2-dihydro-pyrimido
[3,2-c][1,2,4]triazin-4,6-dione (13).
Equimolar mixture of 11 and
p-chlorobenzaldehyde in EtOH (50 mL)-piperidine drops was refluxed
for 2 h then cooled and poured into ice. The produced solid was filtered
and crystallized from dioxan to give 13 as yellowish crystals, yield
65%; mp 256–258°C; UV (ʎmax nm):360; IR (ʋꢀcm1): 3300,3143
(NH, NH), 2209 (C≡N), 1663 (C¼O), 1640 (C¼O), 1586 (C¼N),
1487, 1458 (deformation CH¼), 1391 (cyclic NCN), 1256 (C–F),
862, 826, 812, 780 (P-substituted ring), 680 (C–Cl), 656 (C–F); 1H-
NMR (δ ppm): 8.61, 8.59 (each s, 1H, 1H, NH, NH), 8.12–8.10,
8.097–8.08 (m, 2H of coupling aryl with α and β carbons of styryl),
7.999, 7.95–7.92, 7.89–7.82, 7.74–7.65, 7.60–7.55, 7.248–7.229,
7.214–7.200, 7.176–7.143 (each s, 8H, aromatic protons), 3.82–3.45,
3.229–3.024 (each m, 2H, CH¼CH); 13C-NMR (δ ppm): 160.81
(C¼O), 160.75 (C¼O), 160.50 (C–F), 132.82 (C–Cl), 132.03,
131.94–131.92, 131.16–131.10, 130.56–130.50, 130.48–130.43,
130.25, 129.896, 129.83, 128.96, 128.51, 125.52 (12 carbons of aro-
matic rings), 115.98–115.955, 115.83–115.81 (C¼C of pyrimidine),
115.63 (6C of 1,2,4-triazine), 115.49 (C≡N), 77.96–77.53 (NCN of
1,2,4-triazine), 56.54 (C¼N), 36.29, 33.54 (two aliphatic carbons
(=CH–Ar); Anal. Calcd. C, 58.82; H, 2.69; N, 17.15; F, 4.65; Cl,
8.82% for C20H11N5FClO2 (408). Found: C, 58.52; H, 2.34; N,
16.88; F, 4.35; Cl, 8.59%.
8-(4′-Fluorophenyl)-3′-[2-(4′-fluorobenzoyl)aminophenyl]-7-
cyano–pyrimido[3,2-c] [1,2,4] triazin-4,6-dione (9).
Equimo-
lar mixture of compound 7 and 4-fluorobenzoylchloride in DMF
(10mL) was warmed for 30min, cooled then poured into ice. The
solid thus obtained filtered off and crystallized from dioxan to give 9
as reddish crystals, yield 60%; mp 221–223°C; IR (ʋꢀcm1): 3220–3190
(b, NH), 3020 (Ar CH), 2220 (C≡N) 1660, 1590 (C¼O, CONH),
1
1250 (C–F),900,800–820 (aryl CH), 660 (C–F); H-NMR (δ ppm)
10.8 (s, 1H, OH), 8.18–6.89 (m, 8H, aryl protons); 13C-NMR (δ
ppm) = 163.0 162.12, 145.16, 133.94, 130.76, 130.71, 129.54,
128.74,125.17, 122.57, 121.43, 116.04,110.37, 78.14–77.55,
66.79; Anal. Calcd. C, 62.90; H, 2.82; N, 16.93; F, 7.66%. For
C26H14N6F2O3 (496). Found: C, 62.49; H, 2.58; N 16.61; F 7.35%.
11-(4′-Fluorophenyl)-10-cyano-1H-pyrimido[3,2-c][1,2,4]triazino
[6,5-b]indole (10).
A mixture of 2 (0.01 mol) and isatin (0.01 mol)
in DMF was refluxed for 2 h then cooled. The yielded solid was filtered
and crystallized from dioxan give 10 as brown crystals, yield 65%; mp
304–305°C; UV (ʎmax nm): 373; IR (ʋꢀcm1) = 3201 (NH), 2225 (C≡N),
1666 (C¼O), 1608, 1541 (C¼N), 1384 (cyclic NCN), 1238 (C–F),
894, 843, 815, 785 (O,P-substituted ring), 656 (C–F); MS (Int%)
= 356 (11.18), 328 (38.12), 300 (13.00), 274 (33.43), 179 (45.81), 95
(100); Anal. Calcd. C, 64.04; H, 2.52; N, 23.59; F, 5.33%. For
C19H9N6FO (356). Found: C, 63.74; H, 2.35; N, 23.29; F, 5.21%.
8-(4′-Fluorophenyl)-7-cyano-1,2,3,4-tetrahydro-pyrimido[3,2-
8-(4′-Fluorophenyl)-4-aryldene-7-cyano-1,2-dihydro-pyrimido
[3,2-c][1,2,4]triazin-3,6-dione (14).
Equimolar mixture of 12 and
p-chlorobenzaldehyde in EtOH (100 mL)-piperidine drops was
refluxed for 2 h then cooled and poured into ice. The produced solid
was filtered and crystallized from ethanol to give 14 as faint yellow
crystals, yield 58%; mp 231–232°C.; IR (ʋꢀcm1): 3500–3400 (b, NH,
OH), 3020 (Ar–CH), 2910 (R–CH), 2180 (C≡N), 1708 (C¼O),
1590, 1580 (C¼C, C¼N), 1380 (NCN), 1240 (C–F), 840, 810 (Ar–
CH), 710, 660 (C–Cl and C–F); Anal. Calcd. C, 58.82; H, 2.69; N,
17.15; F, 4.65; Cl, 8.82% for C20H11N5FClO2 (408). Found: C,
58.55; H, 2.39; N, 16.89; F, 4.41; Cl, 8.55%.
c][1,2,4]triazin-4,6-dione (11).
Equimolar mixture of 2 and
chloroacetic acid in NaOH (5% 1:1, 100 mL) was refluxed for 4 h
then cooled and poured into ice HCl. The produced solid was filtered
and crystallized from THF to give 11 as yellowish crystal, yield
66%; mp 167–168°C.
IR (ʋꢀcm1) = 3366 (NH), 3152 (NH), 3090 (aromatic CH), 2890
(aliphatic CH), 2217 (C≡N), 1668 (C¼O), 1639 (CONH), 1612
(C¼N), 1556 (C¼N), 1489 (deformation CH), 1395 (cyclic
NCN), 1238 (C–F), 842, 811 (P-substituted ring), 779 (C–F);
1H-NMR (δ ppm): 12.21–12.06 (s, 1H, NH), 11.70 (s, 1H, NH),
7.98–7.95, 7.88–7.87, 7.77–7.45, 7.24–7.10 (each s, 4H, aromatic
protons), 5.41 (s, 1H, OH of –COCH2), 3.065–2.97 (s, 2H, NH);
13C-NMR (δ ppm): 170.01 (C¼O), 161.76 (C¼O), 153.23 (C–F),
8-(4′-Fluorophenyl)-7-cyano-4-hydroxy-pyrimido[3,2-c][1,2,4]
triazin-6-one (15) and 8-(4′-fluorophenyl)-7-cyano-3-hydroxy-
pyrimido[3,2-c][1,2,4]triazin-6-one (16).
A mixture of com-
pounds 11 and/or 12 (0.2 g) and FeCl3 (0.2 g) in MeOH (20 mL)
was refluxed for 3 h then filtered while hot. The solid thus
obtained from filtrates filtered off and crystallized from dioxan to
give 15 and 16 as deep brown crystals.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

F. M. S. Aqlan, M. S. T. Makki, and R. M. Abdel-Rahman
Vol 000
[13] Abdel-Rahman, R. M.; Makki, M. S. T.; Al Sayed, T. A.;
Ibrahim, M. A. Eur J Chem 2010, 1, 236.
[14] Ali, T. E.; Abdel-Rahman, R. M.; Hanafy, F. I.; El-Edfawy, S. M.
Phosphorus, Sulfur, and Silicon 2008, 183, 2565.
[15] Leyla Yurttas, L.; Demirayak, S.; Ilgin, S.; Atli, O. Bioorg
Med Chem 2014, 22, 6313.
15, yield 68%; mp 154–155°C; UV (ʎmax nm): 375 nm; IR
(ʋꢀcm1): 3450 (OH), 2220 (C≡N), 1680 (C¼O), 1250 (C–F); Anal.
Calcd. C, 55.12; H, 2.12; N, 24.73; F, 6.71% for C13H6N5FO2
(283). Found: C, 54.89; H, 1.98; N, 24.35; F, 6.0% soluble in
NaOH solution in cold water.
[16] Patel, A. B.; Chikhalia, K. H.; Kumari, P. J. Saudi Chem Soci
2014, 18, 646.
16, yield 66%; mp 228–230°C; UV (ʎmax nm): 378 nm; IR
(ʋꢀcm1): 3470 (OH), 2195 (C≡N), 1670 (C¼O), 1230 (C–F); Anal.
Calcd. C, 55.12; H, 2.12; N, 24.73; F, 6.71% for C13H6N5FO2
(283). Found: C, 54.69; H, 1.88; N, 24.49; F, 6.55% soluble in
NaOH solution in cold water.
[17] El-Naggar, S. A.; El-Barbary, A. A.; Mansour, M. A.;
Abdel-Shafy, F.; Talat, S. Inter J Cancer Res 2011, 7, 278.
[18] Abdel-Rahman, R. M. Pharmazie 2000, 56, 195.
[19] Smart, B. E. J Fluorine Chem 2001, 109, 3.
[20] Ojima, J. M.; McCarthy, J. T.; Welch, J. T. Biomedical Fron-
tiers of Fluorine Chemistry; American Chemical Society: Washington,
DC., 1996.
[21] Abdel-Aziz, S. A. Phosphorus sulfur and Silicon 1996, 116, 39.
[22] Abdel-Rahman, R. M.; Morsy, J. M.; Allimony, H. A.;
Abdel-Monem, W. R. Boll Chim Farmaceutico 1999, 138, 176.
[23] (a)Abdel-Monem, W. R.; Abdel-Rahman, R. M. Inter J Chem
2006, 16, 1; (b)Gebauer, M. G.; Mckinlay, C.; Gready, J. E. Eur J Med
Chem 2003, 38, 719.
[24] Abdel-Rahman, R. M.; Abdel-Monem, W. R. Indian J Chem
2007, 86B, 38.
[25] Burdge, E. I. Pest Manag Sci 2000, 56, 245.
[26] Tice, C. M. US. 1994, 5300477, Chem. Abstr. 122, 31543.
[27] Gebouer, M. G.; McKinlay, C.; Gready, J. E. Eur J Med Chem
2003, 38, 719.
Acknowledgments. The authors are thankful to the Chemistry
Department at King Abdulaziz University for providing the
research facilities.
REFERENCES AND NOTES
[1] Aly, H. M.; Saleh, N. M.; Elhady, H. A. Eur J Med Chem
2011, 46, 4566.
[2] Kakeri, M.; Nasef, M. M.; Abouzari-Lotf, E. J Mol Liq 2014,
199, 267.
[3] Liu, Z.; Wu, S.; Wang, Y., Li, R.; Wang, J.; Wangf, L.; Zhao, Y.;
Gong, P. Eur J Med Chem 2014, 87, 782.
[4] Makkii, M. S. T.; Bakhotmah, D. A.; Abdel-Rahman, R. M.;
El-Shahawy, M. S. Inter J Org Chem 2012, 2, 311.
[5] Bannwarth, P.; Gree, D.; Das, S.; Yadav, J. J.; Gree, R.
J Fluorine Chem 2011, 132, 3.
[28] The Merck index & Co. Inc. Whitehouse Station, NJ. USA,
9935, 2006.
[29] Eue, L.; Tietz, H. Pflanzen Schutz – Nachr 1970, 23, 208;
Chem Abstr. 1972, 77, 330196a.
[30] Abdel-Rahman, R. M.; Abdel Malik, M. S. Pakistan J Sci Ind
Res 1990, 33, 142.
[6] Al-Issa, S. A. Saudi Pharma J 2013, 21, 305.
[7] Abdel-Rahman, R. M.; El-mahdy, K. Heterocycles 2012, 85,
2391.
[8] Bacelar, A. H.; Carvalho, M. A.; Proenca, M. F. Eur J Med
Chem 2010, 45, 3234.
[31] (a) Abdel-Rahman, R. M. Pharmazie 2001, 56, 195; (b)
Abdel-Rahman, R. M. Pharmazie 2001, 56, 18.
[9] Atta, K. F. M.; Farahat, O. M.; Ghobashy, S. M.; Marei, M. G.
Molecules 2011, 16, 10387.
[10] Zhou, Y.; Wei, L.; Brady, T. P.; Redddy, P. S.; Nguyen, T.;
Chen, J.; Au, Q.; Yoon, I. S.; Yip, G.; Zhang, B.; Barber, J. R.; Ng, S. C.
Bioorg Med Chem Lett 2009, 19, 4303.
[32] Chamberlain, K.; Carter, G. A. Pestic Sci 1980, 11, 526.
[33] Finny, D. J. Estimation of the Median Effective Dose-response
Curve. In Probit Analysis; Cambridge University Press: New York, USA,
1971. Chapter 3; pp. 20–48.
[34] Argudo, C.; Paloua, L.; Bermejo, A.; Cano, A.; del Río, M. A.;
González-Mas, M. C. Postharvest Biology and Technology 2012,
68, 47.
[11] Abdel-Rahman, R. M.; Makki, M. S. T.; Ali, T.; Ibrahim, M. A.
Curr Org Synth 2012, 9, 1.
[12] Ibrahim, M. A.; Abdel-Rahman, R. M.; Abdel-Halim, A. M.;
Ibrahim, S. S.; Allimony, H. A. ARKIVOC 2008, XVI, 202.
[35] Zaher, H. A.; Ibrahim, Y. A.; Mohammady, R. J Heterocycl
Chem 1984, 21, 905.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet