Synthesis of some derivatives of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine; a novel heterocyclic system

Article abstract of DOI:10.3184/174751915X14428472915706

Several new derivatives of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine have been synthesised through the reaction of 5-hydrazinyl-1H-tetrazole with 5-bromo-2,4-dichloro-6-methylpyrimidine in CHCl₃ solution at ambient conditions. Further trea

Full text of DOI:10.3184/174751915X14428472915706

JOURNAL OF CHEMICAL RESEARCH 2015
VOL. 39 OCTOBER, 609–611
RESEARCH PAPER 609
Synthesis of some derivatives of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine;
a novel heterocyclic system
Negin Noorolahian and Ali Shiri*
Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran
Several new derivatives of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine have been synthesised through the reaction of 5-hydrazinyl-1H-
tetrazole with 5-bromo-2,4-dichloro-6-methylpyrimidine in CHCl3 solution at ambient conditions. Further treatment of the synthesised
compound with secondary amines gave the corresponding substituted heterocycles which were subsequently cyclised into pyrimido[5,4-e]
tetrazolo[5,1-c][1,2,4]triazines as derivatives of a novel heterocyclic system on treatment with NaNH2 in CH3CN.
Keywords: pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine, heterocyclisation, 5-hydrazinyl-1H-tetrazole
Tetrazoles are a class of heterocycles that have received attention
due to their wide range of applications. They have been used
as explosives and rocket and gun propellants in construction
and mining, in emergency escape devices and in automobile
air bags.1-3 This nitrogen-rich ring system is also used in
pharmaceuticals.4-6 In addition, they are important as synthons
and precursors of carbenes in flash vacuum pyrolysis7 and have
a wide range of practical applications in organic syntheses.8
The other main application of tetrazole derivatives is as gas-
generating compositions.9 Various tetrazole-based compounds
have also shown good coordination properties and are able to
form stable complexes with several metal ions.10-12
corresponded to the phenyl moiety and the removal of the broad
singlet signal at 6.70 ppm from the NH2 group of the precursor
2 was replaced by the appearance of two NH signals at δ 8.46
and 8.60. In the IR spectrum, the disappearance of stretching
vibration bands for the NH2 group at ν 3346 and 3238 cm-1
also confirmed the occurrence of themhaxydrazine substitution
step. Compound 4 was further treated with various secondary
amines in refluxing EtOH, and gave the corresponding
substituted derivatives 5a–d in quantitative yields.
In an attempt to prepare new
derivatives of the pyrimido
ring system, compounds
[5,4-e]tetrazolo[5,1-c][1,2,4]triazine
5a–d were treated
with NaNH2 in refluxing acetonitrile. After
Furthermore, tetrazole derivatives have been used in organic
synthesis as derivatising agents for the chemical modification of
alcohols.13 They are also significant precursors for the synthesis
of various nitrogen-containing heterocycles and in many useful
transformations.14
On the other hand, there are reviews dealing with the synthesis
of condensed 1,2,4-triazines.15–17 This heterocyclic moiety plays
a vital role in many biological activities including antiviral,18
antihypertensive,19 blood-platelet aggregation inhibitory,20
analgesic,21 and antibacterial properties22, 23 as well as some new
anti-HIV and anticancer agents.24
Encouraged by the research activities in the field of tetrazole
and triazine moieties and in pursuit of our continuing interest in
developing new protocols for the synthesis of new heterocyclic
ring systems,25 we envisioned the synthesis of new derivatives
of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine 6a–d as a
novel heterocyclic ring system.
8 h it was observed that the only products obtained were 6a–d,
derivatives of a novel heterocyclic system.
Beside the correct elemental analyses, the spectral data of
compounds 6a–d are in agreement with the assigned structures.
For instance, the IR spectrum of compound 5a displayed two
stretching vibration bands for the NH group at νmax 3283 and
1
3117 cm–1. The H NMR spectrum showed the signals for the
pyrrolidine moiety at 1.83 and 3.03 ppm, a singlet at 2.48 ppm
due to the methyl protons, a multiplet in the region 7.09–7.63
ppm due to the phenyl group and two signals at 6.67 ppm and
8.07 ppm corresponding to the NH groups. The mass spectrum
of 5a showed a molecular ion peak at m/z 416 (M+) consistent
with a molecular formula of C16H18BrN9.
The IR spectrum of compound 6b displayed a stretching
vibration band for the NH group at νmax 3333 cm–1. The 1H NMR
spectrum showed the signals of the morpholine moiety at 2.50
and 3.39 ppm, a singlet signal at 2.36 ppm due to the methyl
protons, a multiplet in the range 6.98–7.66 ppm due to the
phenyl group and a signal at 9.32 ppm corresponding to the NH
group. The mass spectrum of 6b showed a molecular ion peak
at m/z 351 (M+) related to the molecular formula of C16H17N9O.
Results and discussion
The starting material, 1-phenyl-5-methylsulfanyltetrazole 1 was
easily obtained from the treatment of phenyl isothiocyanate
with NaN3 in the presence of pyridine in water at room
temperature and subsequent methylation with methyl iodide.26
The reaction of compound 1 with hydrazine hydrate gave,
quantitatively, the desired hydrazine derivative 2 which has been
synthesised previously with modifications, but not completely
characterised.27-29 On the other hand, 5-bromo-2,4-dichloro-
6-methylpyrimidine 3 was prepared through the reaction of
thiourea and ethyl acetoacetate in a four-stage method.30 The
treatment of compound 2 with the latter in a mixture of NaOH
in DMF at 0 ºC afforded 5-bromo-2-chloro-4-methyl-6-[2-(1-
phenyl-1H-tetrazol-5-yl)hydrazinyl]pyrimidine 4 (Scheme 1).
Conclusion
In summary, we have demonstrated a novel and efficient
synthetic protocol for the preparation of the pyrimido[5,4-e]
tetrazolo[5,1-c][1,2,4]triazine systems 6a–d. The desired
ring formation could be carried out through the treatment
of 5-hydrazinyl-1-phenyl-1H-tetrazole 2 and 5-bromo-2,4-
dichloro-6-methylpyrimidine 3 in NaOH/DMF which was
subsequently treated with secondary amines in boiling EtOH.
The reaction of the hydrazinyltetrazoles 5a–d with NaNH2
in CH3CN eventually gave the desired novel derivatives of
1
The H NMR spectrum of compound 3 showed a singlet
the
pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine
system
signal at 2.5 ppm indicating the presence of the CH3 group
6a–d. These new compounds like all other biologically
of the pyrimidine ring, a multiplet in the range δ 6.61–7.53
active heterocyclic compounds may be good candidates for
* Correspondent. E-mail: alishiri@um.ac.ir

610 JOURNAL OF CHEMICAL RESEARCH 2015
SMe
Ph
HN
N
NH2
Ph
N
NH2NH2
N
N
N
N
N
N
H
N
N
C
l
C
HN
Ph
1
2
DMF/NaOH
0 °C
N
N
Br
N
N
N
N
l
C
H
3
Cl
Br
4
N
H
C
3
R2NH
Et H
O
3
reflux
H
H
N
N
NR2
N
N
C
NR2
N
HN
N
Ph
NaNH2
N
N
Ph
N
N
N
N
N
H N
C 3C
Br
H
C
N
3
N
H
3
5a-d
6a-d
a
c
Entry
R2NH
b
d
HN
HN
HN
HN
N
O
Ph
Scheme 1
dichloro-6-methylpyrimidine 3 (0.24 g, 1 mmol) and powdered NaOH
(1 g) in DMF (5 mL) at temperature of 0–5 ºC. After the completion
of the reaction, which was monitored by TLC using EtOAc: n-hexane
(3:7) as eluent, water (10 mL) was added and the resulting solid was
separated and washed with water (2 × 10 mL) and dried in vacuo.
Further purification was performed by washing the precipitate with
petroleum ether.Yield 90%; m.p. 250–252 C, H NMR (DMSO-d6)
δH 2.50 (3H, s, CH3), 6.61–7.53 (5Harom, m, phenyl), 8.46 (1H, s, NH),
8.60 (1H, s, NH); 13C NMR (100 MHz, DMSO-d6) δc 23.8, 115.2, 117.4,
117.5, 121.7, 128.8, 129.1, 144.7, 162.3, 167.4; IR (KBr) νmax/cm-1 3361,
2941, 2916, 1624; MS (m/z) 381 (M), 383 (M+2), 345 (M-Cl, 35), 330
(M-Cl,-CH3, 15). Anal. calcd for C12H10BrClN8: C, 37.77; H, 2.64; N,
29.36; found: C, 37.69; H, 2.58; N, 29.28%.
investigating their pharmaceutical properties in biological
systems. These studies are in progress in our laboratory and
will be published in due course.
Experimental
Melting points were recorded on an Electrothermal type 9100 melting
point apparatus. The IR spectra were obtained on Avatar 370 FTIR
Thermo Nicolet spectrophotometer and only noteworthy absorptions
º
1
1
are listed. The H NMR and 13C NMR spectra were recorded on a
Bruker Avance DRX-400 spectrometer. Chemical shifts are reported
in ppm downfield from TMS as internal standard. The mass spectra
were scanned on a Varian Mat CH-7 instrument at 70 eV. Elemental
analyses were performed on a Thermo Finnigan Flash EA 1112
microanalyser.
Preparation
of
2-amino-5-bromo-4-methyl-6-[2-(1-phenyl-1H-
5-Hydrazinyl-1-phenyl-1H-tetrazole (2): Excess hydrazine hydrate
(2 mL) was added to a stirred solution of 5-(methylthio)-1-phenyl-1H-
tetrazole (1) (0.19 g, 1 mmol) in pyridine (2 mL) and the solution was
refluxed for 1 day. After the completion of the reaction, the solvent was
removed under reduced pressure and the resulting solid was washed
with water (2 × 20 mL) and recrystallised from EtOAc to obtain the
tetrazol-5-yl)hydrazinyl]pyrimidines 5a–d; general procedure
The appropriate secondary amine (1.5 mmol) was added to a
stirred solution of compound 4 (0.38 g, 1 mmol,) and Et3N (0.2 mL,
1.5 mmol,) in EtOH (5 mL), and the solution was heated under reflux
for 12 h. After the completion of the reaction, the mixture was cooled
and the solvent was removed under reduced pressure. The resulting
solid was washed with water (2 × 10 mL) and recrystallised from
EtOH.
1
pure product as a white solid; yield 57%; m.p. 215–217 ºC, H NMR
(400 MHz, DMSO-d6) δH 6.70 (2H, s, NH2), 6.95–6.98 (3Harom, m,
phenyl), 7.32–7.36 (2Harom, m, phenyl), 9.2 (1H. s, NH). 13C NMR (100
5-Bromo-4-methyl-6-[2-(1-phenyl-1H-tetrazol-5-yl)hydrazinyl]-
2-(pyrrolidin-1-yl)pyrimidine (5a): White powder; yield 75%;
MHz, DMSO-d6) δC 128.4, 128.7, 128.8, 129.3, 156.4; IR (KBr) νmax
/
cm-1 3346, 3238, 3113, 3031, 1643; MS (m/z) 176 (M). Anal. calcd
for C7H8N6: C, 47.72; H, 4.58; N, 47.70; found: C, 47.65; H, 4.50; N,
47.61%.
1
m.p. 200–202 ºC; H NMR (DMSO-d6) δH 1.83 (4H, t, J = 6.2 Hz,
CH2-pyrrolidine), 2.48 (3H, s, -CH3), 3.03 (2H, t, J = 6.2 Hz, CH2N-
pyrrolidine), 3.45 (2H, s, CH2N-pyrrolidine), 7.09–7.63 (5Harom, m,
phenyl), 6.67 (1H, s, NH), 8.07 (1H, s, NH); 13C NMR (DMSO-d6): δc
23.5, 25.1, 54.1, 96.3, 128.1, 128.2, 129.0, 155.6, 158.2, 165.2, 169.1;
IR (KBr) νmax/cm-1 3283, 3117, 2964, 2917, 2867, 1622,750; MS (m/z)
5-Bromo-2-chloro-4-methyl-6-[2-(1-phenyl-1H-tetrazol-5-yl)
hydrazinyl]pyrimidine (4): 5-Hydrazinyl-1-phenyl-1H-tetrazole
2
(1 mmol, 0.18 g) was added slowly to a stirred mixture of 5-bromo-2,4-

JOURNAL OF CHEMICAL RESEARCH 2015 611
415 (M), 417 (M+2). Anal. calcd for C16H18BrN9: C, 46.16; H, 4.36; N,
30.28; found: C, 46.02; H, 4.30; N, 30.21%
powder; yield 78%; m.p. 205–207 ºC; 1H NMR (DMSO-d6) δH 2.40 (3H,
s, CH3), 2.85–2.92 (8H, m, CH2), 6.89–7.40 (10H, m, phenyl), 9.50 (1H, s,
NH); 13C NMR (DMSO-d6) δc 17.5, 49.5, 49.6, 117.5, 114.6, 119.3, 121.7,
122.3, 129.6, 129.7, 143.3, 146.4, 149.5, 150.4, 156.2, 154.3; IR (KBr)
4-(5-Bromo-4-methyl-6-[2-(1-phenyl-1H-tetrazol-5-yl)hydrazinyl]-
2-(morpholin-4-yl)pyrimidine (5b): White powder; yield 71%;
m.p. 180–181 ºC; 1H NMR (DMSO-d6) δH 2.43 (3H, s, CH3), 3.65
(4H, t, J = 6.1 Hz, CH2N-morpholine), 3.74 (4H, t, J = 6.1 Hz, CH2O-
morpholine), 6.71 (1H, s, NH), 7.45–7.62 (5H, m, phenyl), 8.12 (1H, s,
NH); 13C NMR (DMSO-d6) δc 23.1, 48.9, 66.7, 96.1, 128.1, 128.4, 129.2,
156.0, 158.3, 165.2, 169.3; IR (KBr) νmax/cm-1 3333, 2959, 2850, 1666,
751; MS (m/z) 431 (M), 433 (M+2). Anal. calcd for C16H18BrN9O: C,
44.46; H, 4.20%; N, 29.16; found: C, 44.39; H, 4.16; N, 29.10%.
5-Bromo-4-methyl-6-[2-(1-phenyl-1H-tetrazol-5-yl)hydrazinyl]-
2-(piperidin-1-yl)pyrimidine (5c): Brown powder; yield 65%;
ν
max/cm-1 3457, 3353, 2962, 2922, 2851, 1620, 749; MS (m/z) 426 (M),
349 (M-Ph), 265 (M-piperazine). Anal. calcd for C22H22N10: C, 61.96; H,
5.20; N, 32.84; found: C, 61.89; H, 5.15; N, 32.77%.
The authors gratefully acknowledge Research Council of
Ferdowsi University of Mashhad for financial support of this
project (3/29091). This paper is dedicated to Prof. Mohammad
Rahimizadeh.
1
m.p. 195–197 ºC; H NMR (DMSO-d6) δH 1.45 (4H, t, J = 6.3 Hz,
Received 13 July 2015; accepted 20 September 2015
Paper 1503492 doi: 10.3184/174751915X14428472915706
Published online: 2 October 2015
CH2CH2CH2N), 1.59 (2H, m, CH2), 2.40 (3H, s, CH3-pyrimidine), 3.71
(4H, t, J = 6.3 Hz, CH2N-piperidine), 6.73 (1H, s, NH), 7.45–7.62 (5H,
m, Ar), 8.05 (1H, s, NH); 13C NMR (DMSO-d6) δc 23.2, 24.3, 25.2,
58.1, 96.3, 128.2, 128.4, 129.3, 156.0, 158.8, 165.5, 169.2; IR (KBr)
References
ν
max/cm-1 3020, 2990, 1592, 1555, 1015; MS (m/z) 429 (M), 431 (M+2).
1
2
G. F. Adams and R. W. Show, Annu. Rev. Phys. Chem., 1992, 43, 311.
V.A. Ostrovskii, M.S. Pevzner, T.P. Kofmna, M.B. Shcherbinin and I.V.
Tselinskii, Targets Heterocycl. Syst., 1999, 3, 467.
Anal. calcd for C17H20BrN9: C, 47.45; H, 4.68; N, 29.30; found: C,
47.40; H, 4.61; N, 29.25%.
3
4
5
6
7
8
M. Hiskey, D.E. Chavez, D.L. Naud, S.F. Son, H.L. Berghout and C.A.
Bome, Proc. Int. Pyrotech. Semin, 2000, 27, 3.
H. Singh, A.S. Chawla, V.K. Kapoor and D. Paul, Prog. Med. Chem., 1980,
17, 151.
5-Bromo-4-methyl-6-[2-(1-phenyl-1H-tetrazol-5-yl)hydrazinyl]-2-
(4-phenylpiperazin-1-yl)pyrimidine (5d): Brown powder; yield 78%;
m.p. 205–206ºC; 1H NMR (DMSO-d6) δH 2.43 (3H, s, CH3), 3.23 (4H,
t, J = 6.3 Hz, CH2N), 3.51 (4H, t, J = 6.3 Hz, CH2N), 6.73–7.59 (10Harom
,
T. Ichikawa, T. Kitazaki, Y. Matsushita, H. Hosono, M. Yamada, M.
Mizuno and K. Itoh, Chem. Pharm. Bull., 2000, 48, 1947.
T. Ichikawa, M. Yamada, M. Yamaguchi, T. Kitazaki, Y. Matsushita, K.
Higashikawa and K. Itoh, Chem. Pharm. Bull., 2001, 49, 1110.
D.J. Carini, V.D. John, E.A. Paul and T.C. Andrew, J. Med. Chem., 1991,
34, 2525.
V.A. Ostrovskii, G.I. Koldobskii and R.E. Trifonov, Comprehensive
heterocyclic chemistry III, eds A.R. Katritzky, C.A. Ramsden, E.F.V.
Scriven and R.J.K Taylor, Elsevier, Oxford, 2008, Vol. 6, p. 257.
H. Bock, R. Dammel, S. Fisher and C. Wentrup, Tetrahedron Lett., 1987,
28, 617.
m, phenyl); 13C NMR (DMSO-d6) δc 23.2, 49.5, 49.6, 96.3, 114.1, 121.7,
128.6, 128.4, 128.3, 129.6, 129.5, 149.1, 156.0, 158.3, 165.2, 169.1; IR
(KBr) νmax/cm-1 3457; 3353, 2962, 2922, 1620, 749; MS (m/z) 506 (M),
508 (M+2), 429 (M-Ph), 345 (M-piperazine), 266 (M-Br), 251 (M-
CH3), 174 (M-Ph). Anal. calcd for C22H23BrN10: C, 52.08; H, 4.57; N,
27.61; found: C, 51.98; H, 4.50; N, 27.53%.
Preparation of pyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazines 6a–d;
general procedure
9
10 P.N. Gaponik, S.V. Voitekhovich and O.A. Ivashkevich, Russ. Chem. Rev.,
2006, 75, 507.
11 J.R. Anacona and P. Alvarez, Trans. Met. Chem., 2002, 27, 856.
12 Z.H. Chohan, C.T. Supuran and A. Scozzafava, J. Enzyme. Inhibit. Med.
Chem., 2004, 19, 79.
13 L.M.T Frija, R. Fausto and R.M.S. Loureiro, J. Mol. Cat. A Chem., 2009,
305, 142.
14 N.C.P Araujo, P.M.M. Barroca, J.F. Bickley and A.F. Brigas, J. Chem. Soc.,
Perkin Trans. 1, 2002, 1213.
15 E.S.H. El Ashry, N. Rashed, M. Taha and E. Ramadan, Adv. Heterocycl.
Chem., 1994, 59, 39.
16 E.S.H. El Ashry, N. Rashed, A. Mousaad and E. Ramadan, Adv. Heterocycl.
Chem., 1994. 61, 207.
17 H. Neunhoeffer and P.F. Wiley, Chem. Heterocycl. Compd., 1978, 33, 749
18 V.L. Rusinov, E.N. Ulomskii, O.N. Chupakhin and V.N. Charushin, Russ.
Chem. Bull., 2008, 57, 985.
19 W.P. Heilman, R.D. Heilman, J.A. Scozzie, R.J. Wayner, J.M. Gullo and
Z.S. Ariyan, J. Med. Chem., 1979, 22, 671.
20 A. Monge, J. Palop, C. Ramirez, M. Font and E. Fernandez-Alvarez, Eur.
J. Med. Chem., 1991, 26, 179.
21 H.M. Ashour, O.G. Shaaban, O.H. Rizk and I.M. El-Ashmawy, Eur. J. Med.
Chem., 2013, 62, 341.
22 A.M. Dave, K.N. Bhatt, N.K. Undavia and P.B. Trivedi, J. Indian Chem.
Soc., 1989, 66, 246.
23 M.A.E. Shaban, M.A.M. Taha and A.E.A. Morgaan, Monatsh. Chem.,
2000, 131, 487.
24 R.M. Abdel-Rahman, J.M. Morsy, S. El Edfawy and H.A. Amine,
Pharmazie, 1999, 54, 667.
25 A. Hazrathoseyni, S.M. Seyedi, A. Shiri and H. Eshghi, J. Chem. Res.,
2015, 39, 148.
26 S.Y. Han, J.W. Lee, H-J. Kim, Y-J. Kim, S.W. Lee and Y.S. Gyoung, Bull.
Korean Chem. Soc., 2012, 33, 55.
27 K. Ehrmann, D. Rieder, H. Wille, H. Winter and F. Henke-Stark, J. Prakt.
Chem., 1932, 134, 282.
A mixture of compounds 5a–d (1 mmol) and NaNH2 (0.12 g, 3 mmol)
in dry CH3CN (5 mL) was heated for 8 h under reflux. After completion
of the reaction, the solvent was removed under reduced pressure and the
mixture was neutralised with acetic acid. The precipitate was filtered off,
washed with water and recrystallised from EtOH.
9-Methyl-3-phenyl-7-(pyrrolidin-1-yl)-3,5-dihydropyrimido[5,4-e]
tetrazolo[5,1-c][1,2,4]triazine (6a): Brown powder; yield 76%; m.p.
1
225–226 ºC; H NMR (DMSO-d6) δH 1.92 (4H, t, J = 7.1 Hz, CH2),
2.33 (3H, s, CH3), 3.32 (4H, t, J = 7.1 Hz, CH2N), 6.76–7.20 (5Harom
,
m, phenyl), 8.07 (1H, s, NH); 13C NMR (DMSO-d6) δc 17.5, 25.3, 54.1,
117.4, 119.0, 122.8, 129.1, 144.2, 150.3, 155.1, 156.6; IR (KBr) νmax/cm-1
3422, 3143, 2966, 2923, 2854, 1626; MS (m/z) 335 (M), 258 (M-Ph),
243 (M-CH3), 173 (M-pyrrolidine). Anal. calcd for C16H17N9: C, 57.30;
H, 5.11; N, 37.59; found: C, 57.24; H, 5.05; N, 37.49%.
9-Methyl-3-phenyl-7-(morpholin-4-yl)-3,5-dihydropyrimido[5,4-e]
tetrazolo[5,1-c][1,2,4]triazine (6b): Brown powder; yield 65%; m.p.
º
1
180–181 C; H NMR (DMSO-d6) δH 2.36 (3H, s, CH3), 2.50 (4H, t,
J = 6.4 Hz, CH2N), 3.39 (4H, t, J = 6.4 Hz, CH2O), 6.98–7.66 (5Harom
,
m, phenyl), 9.32 (1H, s, NH); 13C NMR (DMSO-d6) δc 17.4, 48.8, 66.4,
117.4, 119.1, 122.3, 129.5, 144.9, 150.5, 155.6, 156.8; IR (KBr) νmax/cm-1
3333, 2959, 2850, 1666; MS (m/z) 351 (M), 274 (M-Ph), 259 (M-CH3),
173 (M-morpholine). Anal. calcd for C16H17N9O: C, 54.69; H, 4.88; N,
35.88; found: C, 54.60; H, 4.82; N, 35.79%.
9-Methyl-3-phenyl-7-(piperidin-1-yl)-3,5-dihydropyrimido[5,4-e]
tetrazolo[5,1-c][1,2,4]triazine (6c): Brown powder; yield 65%; m.p.
1
195–197 ºC; H NMR (DMSO-d6) δ 1.24 (6H, m, CH2CH2CH2), 2.26
(3H, s, CH3), 3.35 (4H, t, J = 6.8 Hz,2 × CH2N), 6.88–7.68 (5Harom, m,
Ar), 8.24 (1H, s, NH); 13C NMR (DMSO-d6) δc 17.5, 24.2, 25.1, 54.3,
117.3, 119.0, 122.4, 129.6, 144.8, 150.4, 155.5, 156.7; IR (KBr) νmax/cm-1
3020, 2990, 1592, 1555, 1015; MS (m/z) 349 (M), 265 (M-piperidine),
250 (M-CH3). Anal. calcd for C17H19N9: C, 58.44; H, 5.48; N, 36.08;
found: C, 58.36; H, 5.40; N, 35.98%.
28 M. A. A. Moustafa, A. M. Ismaiel, H. M. Eisa and A. A. El-Emam, J.
Chinese Chem. Soc. (Taipei), 1991, 38, 199.
29 K. Yamazaki, H. Hasegawa, K. Umekawa, Y. Ueki, N. Ohashi and M.
Kanaoka, Bioorg. Med. Chem. Lett., 2002, 12, 1275.
30 M. Bakavoli, M. Nikpour and M. Rahimizadeh, J. Heterocycl. Chem.,
2006, 43, 1327.
9 - Me t h y l -3 - p h e n y l -7- ( 4 - p h e n y l p i p era z i n -1-y l ) -3 , 5 -
dihydropyrimido[5,4-e]tetrazolo[5,1-c][1,2,4]triazine (6d): Brown