Bis-enaminones as precursors for synthesis of novel 3,4-bis(heteroaryl) pyrazoles and 3,6-bis-(heteroaryl)-pyrazolo[3,4-d]pyridazines

Article abstract of DOI:10.3184/174751911X13079876877588

Coupling of bis-enaminones with benzenediazonium chloride and 3-diazo-1,2,4-triazole proved to be convenient routes for the synthesis of novel 3,4-bis(pyrazol-3-yl)pyrazoles and 3,6-bis(heteroaryl)pyrazolo[3,4-d] pyridazines which have not been reported previously. The structures of the products were elucidated on the basis of their spectral properties, elemental analyses and, wherever possible, by alternate synthesis.

Full text of DOI:10.3184/174751911X13079876877588

JOURNAL OF CHEMICAL RESEARCH 2011
RESEARCH PAPER 341
JUNE, 341–345
Bis-enaminones as precursors for synthesis of novel
3,4-bis(heteroaryl)pyrazoles and
3,6-bis-(heteroaryl)-pyrazolo[3,4-d]pyridazines
Ahmad S. Shawali* and Adel J. M. Haboub
Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
Coupling of bis-enaminones with benzenediazonium chloride and 3-diazo-1,2,4-triazole proved to be convenient
routes for the synthesis of novel 3,4-bis(pyrazol-3-yl)pyrazoles and 3,6-bis(heteroaryl)pyrazolo[3,4-d]pyridazines
which have not been reported previously. The structures of the products were elucidated on the basis of their
spectral properties, elemental analyses and, wherever possible, by alternate synthesis.
Keywords: hydrazonoyl halides, heterocycles, enaminones, pyrazoles
Enaminones of type I have been reported to couple with
arenediazonium salts to give the respective hydrazones II
(Scheme 1).1–4 In conjunction with our recent work on bis-
enaminones of type III,5–10 we decided to study their azo cou-
pling with diazotised aromatic and heterocyclic amines and to
explore the reactions of the resulting azo-coupled products IV
and V with hydrazine hydrate. Our aim was to shed some light
on the site selectivity in the latter reactions and explore their
utility to synthesise new ter-heterocycles of type VI and VII
(Fig. 1).
spectra revealed that they exist only in the form Z-3 (Fig. 2).
This is because such spectra revealed, in each case, two singlet
signals in the regions δ 10.35–10.37 and 12.79–12.88 due to
the resonances of the –CHO and hydrazone NH protons,
respectively (see Experimental). These chemical shift values
are similar to those of the syn-isomers (Z-isomers) of 3-aryl-3-
oxo-2-arylhydrazononopropanals (ArCOC(CHO)=NNHAr’)
which were reported to exhibit their –CHO signals at δ 9.50–
1
9.63 and hydrazone NH signals at δ 11.85–12.78.11 The H
NMR spectra of the anti-isomers (E-isomers) of the latter
compounds revealed the signals for their –CHO and NH
proton resonances in the regions δ 9.96–10.17 and 13.9–14.35,
respectively.11
Condensation of the product 3a with hydrazine hydrate was
next examined to shed some light on its site reactivity. This
reaction yielded a single product that was identified, on the
basis of its spectral and elemental analyses, as 4 rather than 5
(Scheme 2). The assigned structure 4 was confirmed by com-
parison with an authentic sample of 5, prepared by an unam-
biguous synthesis as depicted in Scheme 2. Thus, reaction
Results and discussion
The starting bis-enaminones 2a–c were prepared by con-
densation of 3,4-diacetylpyrazole derivatives 1a–c each with
N,N-dimethylformamide dimethyl acetal (DMF-DMA) as pre-
viously described from our laboratory (Scheme 1).10 Coupling
of 2a–c each with a benzenediazonium derivative in ethanol
in the presence of sodium acetate gave the corresponding
coupling products 3a–c (Scheme 1). Although the latter
compounds can exist in the E- and/or Z-forms, their 1H NMR
Fig. 1
* Correspondent. E-mail: as_shawali@mail.com

342 JOURNAL OF CHEMICAL RESEARCH 2011
Scheme 1
Fig. 2
Scheme 2
of 3,6-dimethylpyrazolo[3,4-d]pyridazine 6 with DMF-DMA
yielded the bis-enamine 7. Coupling of the latter with ben-
zenediazonium chloride afforded 5 which proved completely
different from 4 (Scheme 2). The structures of the products
4–7 were consistent with their spectral (IR, 1H NMR and Ms)
and microanalytical data (see Experimental).
Next, we examined coupling of 2a with diazotised 3-amino-
1,2,4-triazole in ethanol in the presence of sodium acetate. The
reaction afforded a product that proved to be the respective
1-phenyl-5-methyl-3,4-bis[1,2,4-triazolo[3,4-c][1,2,4]triazin-
6-yl)carbonyl]pyrazole 8a (Scheme 3). Structure assignment
of the latter was based on its spectral and elemental analysis

JOURNAL OF CHEMICAL RESEARCH 2011 343
Scheme 3
data. For example, its IR spectrum showed no –CHO bands
established on the basis of its spectral (IR, 1H NMR, MS) and
elemental analyses (see Experimental). When 9 was heated
in ethanol in the presence of sodium hydroxide, it isomerised
to the thermodynamically more stable [1,2,4]triazolo[5,1-c]
[1,2,4]triazine derivative 10 via a Dimroth-type rearrangement
through tandem ring opening and ring closure reactions
(Scheme 4). This rearrangement is compatible with those
reported in earlier reports on rearrangements of [1,2,4]
triazolo[3,4-c][1,2,4]triazines and pyrimidines.12,15 Conclusive
evidence for the rearrangement of 9 into 10, was provided by
comparison of their H NMR spectra. For example, the H
NMR spectrum of 9 revealed the H-3 proton signal at δ 8.88,
whereas that of 10 showed the H-7 proton signal at δ 8.47. This
feature is consistent with literature reports which indicate that
the H-3 proton of [1,2,4]triazolo[3,4-c]pyrimidine is more
deshieldedthanthatofH-7of[1,2,4]triazolo[5,1-c]pyrimidine.14
The driving force for this rearrangement seems to be due to the
fact that the [1,2,4]triazolo[5,1-c][1,2,4]triazine ring system
is thermodynamically more stable than its isomer namely
[1,2,4]triazolo[3,4-c][1,2,4]triazine as is the case for the
[1,2,4]triazolopyrimidine isomers.16 This suggestion was con-
firmed by calculating the heats of formation (∆Hf) of both ring
systems at the AM1 level using the Hyperchem program pack-
age (version 4.0).17 The results of these calculations showed
that the enthalpy of formation of [1,2,4]triazolo[3,4-c]
[1,2,4]triazines (106.89 kcal mol−1) is less than that of [1,2,4]
triazolo[5,1-c][1,2,4]triazine (151.56 kcal mol−1).
but instead exhibited a ketonic carbonyl band in the region ν
1
1676–1681 cm−1. Also, its H NMR spectrum did not show a
signal characteristic of a –CHO group, they it exhibited two
characteristic singlet signals at δ 7.87and 8.58 assignable to
H-3 and H-5 of the [1,2,4]triazolo[3,4-c][1,2,4]triazine ring
residue, respectively.12
To account for the formation of 8, it is suggested
(Scheme 3), that the initially formed azo coupled product A
can either undergo in situ cyclisation via elimination of dimeth-
ylamine to give 8 or hydrolysis to give the bis-aldehyde der-
ivative B which in turn undergoes dehydrative cyclisation to
afford 8. However, all attempts to isolate the intermediate B
failed. This suggests that former route involving direct in situ
cyclisation of the intermediate A is the predominant route.
Next, condensation of the diketone 8 with hydrazine hydrate
was examined to see if it would yield 3,6-bis([1,2,4]triazolo
[3,4-c][1,2,4]triazin-3-yl)-1-phenyl-7-methyl-pyrazolo[3,4-d]-
pyridazine 9 or its isomer, namely 3,6-bis([1,2,4]triazolo
[5,1-c][1,2,4]triazin-3-yl)-1-phenyl-7-methylpyrazolo[3,4-d]-
pyridazine 10 (Scheme 3). Literature reports indicate that
the [1,2,4]triazolo[3,4-c][1,2,4]triazine derivatives undergo
readily Dimroth-type rearrangement to give the respective
[1,2,4]triazolo[5,1-c][1,2,4]triazine isomers upon heating in
the presence of a base.13,14 However, when the diketone 8 was
refluxed with hydrazine hydrate for 2 h the product was identi-
fied as the pyrazolopyridazine 9. The structure of the latter was
1
1

344 JOURNAL OF CHEMICAL RESEARCH 2011
Scheme 4
3,4-Bis(2-phenylhydrazo-1,2,3-trioxo-1-propyl)-1-(4-methoxyphe-
Experimental
nyl)-5-methylpyrazole (3c): Pale brown solid, yield 1.0 g (78 %), m.p.
All melting points were determined on Gallenkamp apparatus.
Solvents were generally distilled and dried by standard literature pro-
cedures prior to use. The IR spectra were measured on a Pye-Unicam
SP300 instrument in potassium bromide discs. The 1 H NMR spectra
were recorded on a Varian Mercury VXR-300 MHz spectrometer and
the chemical shifts δ are downfield from tetramethylsilane (TMS)
as an internal standard. The mass spectra were recorded on a GCMS-
Q1000-EX Shimadzu and GCMS 5988-A HP spectrometers, the
ionizing voltage was 70 eV. Elemental analyses were carried out
by the Microanalytical Center of Cairo University, Giza, Egypt. The
bis-enaminones 2 were prepared as previously described from our
laboratory.10
156–158 °C, IR (KBr) νmax/cm−1 3416(NH), 1683, 1731 (C=O).),
1
1025(C–O–C). H NMR (DMSO-d6) δ = 3.31(s, 3H, CH3), 3.83 (s,
3H, OCH3), 7.09–7.54(m, 14H, ArH), 10.37 (s, 2H, 2CHO), 12.79 (s,
2H, 2NH). MS m/z (%) 536(M+, 0.1), 272 (38), 257 (100), 240 (30),
230 (10), 214 (26), 198 (14), 186 (18), 172 (18), 167 (17), 156 (15),
148 (43), 142 (15), 133 (10), 122 (15), 116 (17), 103 (25), 91 (64), 76
(53), 63 (35), 51 (46). Anal. Calcd for C29H24N6O5 (536.55) C, 64.92;
H, 4.51; N, 15.66. Found: C, 65.13; H, 4.70; N, 15.82%.
3,4-Bis(4-phenylhydrazonopyrazol-3-yl)-1-phenyl-5-methyl-pyra-
zole (4): A mixture of compound 3a (0.25 g, 0.5 mmol) and hydrazine
hydrate (10 mL) in absolute ethanol was refluxed for 10 h and the
reaction mixture was then cooled. The solid that precipitated was
filtered off and crystallised from ethanol to give compound 4a as an
orange solid. Yield 0.99 g, (78 %), m.p. > 300 °C, IR (KBr) νmax/cm−1
3418 (NH), 1596 (C=N). 1H NMR (DMSO-d6) δ = 3.31 (s, 3H, CH3),
7.60 (s, 15H, ArH), 7.83 (s, 2H, pyrazole-H), 9.92 (s, 2H, 2NH); MS
m/z (%) 498 (M+, 0.35), 301 (12), 274 (10), 238 (10), 140 (10), 118
(31), 104 (27), 92 (100), 82 (21), 76 (80), 65 (58), 50 (32). Anal. Calcd
for C28H22N10 (498.55) C, 67.46; H, 4.45; N, 28.09. Found: C, 67.75;
H, 4.63; N, 28.27%.
Coupling of bis-enaminones 2a–c with diazotised aniline: A solu-
tion of the appropriate bis-enaminone 2 (1.76 g, 5 mmol) in ethanol
(20 mL) and sodium acetate trihydrate (0.5 g) was cooled in an ice
bath at 0–5°C while being stirred. Portions of the appropriate diazo-
nium salt were added to the cold solution The salt was prepared by
diazotising the appropriate aniline derivative (10 mmol) in hydrochlo-
ric acid (6M, 3 mL) with sodium nitrite (0.70 g, 10 mmol) in water
(5 mL). After all the diazonium salt solution was added, the mixture
was stirred for a further 30 min. while cooling in an ice-bath. The
reaction mixture was then left in a refrigerator for three days. The
solid that precipitated was filtered off, washed with water, dried and
finally crystallised from ethanol to give the respective products 3.
3,4-Bis(2-phenylhydrazo-1,2,3-trioxo-1-propyl)-1-phenyl-5-methyl-
pyrazole (3a): Red solid, yield 1.0 g, (78 %), m.p. 122–124 °C, IR
(KBr) νmax/cm−1 3425(NH), 1689, 1645 (C=O). 1H NMR (DMSO-d6)
δ = 3.36(s, 3H, CH3), 6.7–7.9 (m, 15H, ArH), 10.35 (s, 2H, 2HCO),
12.83 (s, 2H, 2NH). MS m/z (%) 506(M+, 0.11), 169 (8), 153(15), 121
(4), 111 (11), 104 (11), 97 (17), 121 (14), 94 (88), 82 (14), 76 (16), 71
(18), 65 (50), 56 (25), 46 (100). Anal. Calcd for C28H22N6O4 (506.53)
C, 66.40; H, 4.38; N, 16.59. Found: C, 66.70; H, 4.49; N, 16.72%.
3,4-Bis(2-phenylhydrazo-1,2,3-trioxo-1-propyl)-1-(4-methylphe-
nyl)-5-methylpyrazole (3b): Brown solid, yield 1.0 g, (78 %), m.p,
1,4,5-Trimethyl-6-phenyl-6H-pyrazolo[3,4-d]-pyridazine (6):
A
mixture of the pyrazole derivative 1a (0.25 g, 1 mmol) and hydrazine
hydrate (10 mL) in absolute ethanol was refluxed for 10 h and the
reaction mixture was cooled. The solid that precipitated was filtered
off and crystallised from ethanol to give compound 6a as white solid,
0.15 g, 63% yield, m.p. 254–256˚C (EtOH) (lit.16 m.p. 239–240 °C).
1
IR (KBr) νmax/cm−1 1634 (C=N). H NMR (CDCl3): δ = 2.75 (s, 3H,
CH3), 2.89 (s, 6H, 2CH3), 7.49–7.63 (m, 5H, ArH). MS m/z (%): 238
(M+, 100), 117 (13), 141 (12), 77 (45). Anal. Calcd for C14H14N4
(238.29): C, 70.57; H, 5.92; N, 23.51. Found: C, 70.79; H, 6.02;
N, 23.55%.
4,7-Bis(2-dimethylaminovinyl)-3-methyl-2-phenyl-2H-pyrazolo
[3,4-d]pyridazine (7): A mixture of compound 6 (1.5 g, 6.3 mmol)
and N,N-dimethylformamide dimethyl acetal (DMF-DMA) (4.0 g)
was refluxed for 20 h then left to cool. Methanol was added to the cold
mixture. The resulting solid was collected by filtration, washed with
methanol, dried and finally crystallised from ethanol to afford the bis-
enamine 7 as pale orange solid, (1.7 g, 78 % yield), m.p. 242–244 °C.
1H NMR (CDCl3) δ = 2.77 (s, 3H, CH3), 2.87 [s, 6H, N(CH3)2], 2.93
[s, 6H, N(CH3)2], 5.86 (d, J = 13.0 Hz, 2H, =CH), 7.50–7.59 (m, 5H,
ArH), 7.61 (d, J = 13.0 Hz, 2H, =CH); MS m/z (%): 348 (M+, .74), 238
166–168 °C, IR (KBr) νmax/cm−1 3427(NH), 1645, 1687(C=O). H
1
NMR (DMSO-d6) δ = 2.48 (s, 3H, CH3), 3.31(s, 3H, CH3), 6.94–
7.30(m, 14H, ArH), 10.35 (s, 2H, 2CHO), 12.88 (s, 2H, 2NH). MS
m/z (%) 520(M+, 0.1), 315 (15), 256 (16), 241 (100), 224 (27), 198
(28), 168 (19), 155 (20), 142 (20), 132 (50), 118 (14), 104 (33), 90
(93), 76 (36), 64 (59), 50 (22), 46 (10). Anal. Calcd for C29H24N6O4
(520.55) C, 66.91; H, 4.65; N, 16.14. Found: C, 67.15; H, 4.80; N,
16.00%.

JOURNAL OF CHEMICAL RESEARCH 2011 345
(32), 149 (22), 141 (11.26), 118 (28.31), 104 (32.7), 98 (20), 77 (45),
46 (100). Anal. Calcd for C20H24N6 (348.45): C, 68.94; H, 6.94;
N, 24.12. Found: C, 69.05; H, 7.10; N, 24.25%.
(31), 97 (70), 91 (48), 84 (60), 76 (89), 68 (55), 56 (90). Anal. Calcd
for C21H14N12O3 (482.42) C, 52.28; H, 2.93; N, 34.84. Found: C, 52.45;
H, 3.05; N, 35.02%.
4,7-Bis[(2-oxo-1-phenylhydrazono)-3-methyl-2-phenyl-ethyl]-2H-
pyrazolo[3,4-d]pyridazine (5): A solution of bis-enamine 7 (0.35 g,
1 mmol) in ethanol (20 mL) and sodium acetate trihydrate (0.5 g) was
cooled in an ice bath at 0–5°C while being stirred. To the resulting
cold solution was added portions of a cold solution of benzenediazo-
nium chloride prepared by diazotising aniline (0.2 g, 2 mmol) in
hydrochloric acid (6 M, 3 mL) with sodium nitrite (0.14 g, 2 mmol) in
water (10 mL). After all the diazonium salt was added, the mixture
was stirred for a further 30 min. while cooling in an ice-bath. The
reaction mixture was then left in a refrigerator for three days. The
solid that precipitated was filtered off, washed with water, dried and
finally crystallised from the appropriate solvent to give the product 5a
as pale orange solid. Yield (1.0 g, 78 %), mp. > 300 °C, IR (KBr)
Synthesis of 4,7-bis([1,2,4]triazolo[3,4-c][1,2,4]triazin-6-yl)-3-
methyl-1-phenyl-pyrazolo[3,4-d]pyridazine (9): A mixture of com-
pound 8a (0.67 g, 1.5 mmol) and hydrazine hydrate (10 mL) in
absolute ethanol was refluxed for 10 h and the reaction mixture was
cooled. The solid that precipitated was filtered off and crystallised
from (ethanol-dioxane) to give compound 9 as pale green solid. Yield
(0.53 g, 80 %), m.p. 278–280 °C, IR (KBr) νmax/cm−1 1629 (C=N). 1H
NMR (DMSO-d6) δ = 3.32 (s, 3H, CH3), 7.65 (s, 5H, ArH), 7.92 (s,
2H, H-5), 8.88 (s, 2H, H-3). MS m/z (%) 448 (M+, 0.24), 263 (77), 249
(12), 238 (23), 223 (14), 207 (15), 167 (15), 149 (12), 142 (16), 126
(16), 122 (11), 117 (37), 109 (13), 104 (52), 96 (62), 82 (100), 76 (90),
67 (80), 54 (64), 50 (51). Anal. Calcd for C20H12N14 (448.41) C, 53.57;
H, 2.70; N, 43.73. Found: C, 53.72; H, 2.83; N, 43.90%.
Synthesis of 4,7-bis([1,2,4]triazolo[5,1-c][1,2,4]triazin-3-yl)-3-
methyl-1-phenylpyrazolo[3,4-d]pyridazine (10): A mixture of com-
pound 9 (0.5 g, 1 mmol) and potassium hydroxide in absolute ethanol
was refluxed for 3–5 h and the reaction mixture was cooled and poured
into water. The solid that precipitated was filtered off and crystallised
from (ethanol-dioxane) to give the title compound as brown solid.
Yield (0.33 g, 75 %), m.p. > 300 °C, IR (KBr) νmax/cm−1 1629 (C=N).
1H NMR (DMSO-d6) δ = 3.25 (s, 3H, CH3), 7.54 (s, 5H, ArH), 7.92 (s,
2H, H-4), 8.47 (s, 2H, H-7). MS m/z (%) 449 (M++1, 0.60), 368 (13),
263 (58), 237 (34), 223 (12), 207 (18), 193 (10), 165 (11), 151 (15),
141 (17), 135 (13), 123 (16), 117 (28), 110 (28), 105 (18), 97 (60), 83
(63), 76 (50), 68 (57), 54 (100). Anal. Calcd for C20H12N14 (448.41)
C, 53.57; H, 2.70; N, 43.73. Found: C, 53.72; H, 2.83; N, 43.90%.
1
νmax/cm−1 3428 (NH), 1603 (C=O). H NMR (DMSO-d6) δ = 3.32
(s, 3H, CH3), 7.71 (s, 15H, ArH), 10.23 (s, 2H, 2CHO), 12.64 (s, 2H,
2NH); MS m/z (%) 502 (M+, 2), 149 (58), 143 (11), 134 (11), 131 (14),
127 (11), 123 (15), 118 (30), 109 (27), 104 (40), 97 (34), 93 (50),
82 (45), 77 (83), 69 (60), 56 (100), 50 (44). Anal. Calcd for
C28H22N8O2(502.54) C, 66.92; H, 4.41; N, 22.30. Found: C, 67.12;
H, 4.63; N, 22.46%.
3,4-Bis{([1,2,4]triazolo[3,4-c][1,2,4]triazin-6-yl)carbonyl)}-1-
aryl-5-methylpyrazoles (8a–c): A solution of bis-enaminones 2
(1.76 g, 5 mmole) in ethanol (20 mL) and sodium acetate trihydrate
(0.5 g) was cooled in an ice bath at 0–5°C while being stirred. To the
resulting cold solution was added portions of a cold solution of
3-diazo-1,2,4-triazole, prepared by diazotising 3-amino-1,2,4-triazole
(10 mmole) in hydrochloric acid (6M, 3 mL) with sodium nitrite
(0.70 g, 10 mmole) in water (5 mL). After all the diazonium salt solu-
tion was added, the mixture was stirred for further 30 minutes while
cooling in an ice-bath. The reaction mixture was then left in a refrig-
erator for three days. The solid that precipitated was filtered off,
washed with water, dried and finally crystallised from ethanol to give
the respective products.
Received 2 January 2011; accepted 23 May 2011
Paper 1100504 doi: 10.3184/174751911X13079876877588
Published online: 11 July 2011
References
3,4-Bis{([1,2,4]triazolo[3,4-c][1,2,4]triazin-6-yl)carbonyl)}-1-
1
K.M. Al-Zaydi, E.A.A. Hafez and M.H. Elnagdi, J. Chem. Res., 2000, (S)
154, (M) 510.
phenyl-5-methylpyrazole (8a): Deep red solid, yield 1.71 g, (76 %),
1
m.p. 122–124 °C, IR (KBr) νmax/cm−1 1665 (C=O), 1605 (C=N). H
2
3
K.M. Al-Zaydi and R.M. Borik, Molecules, 2007, 12, 2061.
M.A. Al-Shiekh, H.Y. Medrassi, M.H. Elnagdi and E.A. Hafez, Arkivoc,
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NMR (DMSO-d6) δ = 3.38 (s, 3H, CH3), 7.45-7.62 (m, 5H, ArH), 7.87
(s, 2H, H-3), 8.58 (s, 2H, H-5). MS m/z (%) 452 (M+, 0.42), 287 (18),
149 (33), 144 (11), 125 (35), 118 (17), 113 (44), 109 (24), 102 (37),
96 (94), 84 (100), 76 (52), 69 (61), 56 (93).Anal. Calcd for C20H12N12O2
(452.40) C, 53.10; H, 2.67; N, 37.15. Found: C, 53.20; H, 2.82;
N, 37.30%.
4
5
A. Alnajjar; M.M. Abdelkhalik, A. Al-Enezi and M.H. Elnagdi, Molecules,
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3,4-Bis{([1,2,4]triazolo[3,4-c][1,2,4]triazin-6-yl)carbonyl)}-1-(4-
methylphenyl)-5-methylpyrazole (8b): Orange solid, yield 1.86 g,
1
(80 %), m.p. 156–158 °C, IR (KBr) νmax/cm−1 1681 (C=O). H NMR
8
9
A.S. Shawali, S.M. Sherif, M.A.A. Darwish and M.M. El-merzabani,
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(DMSO-d6) δ = 2.43 (s, 3H, ArCH3), 3.39 (s, 3H, CH3), 7.37–7.44 (m,
4H, ArH), 7.96 (s, 2H, H-3), 8.57 (s, 2H, H-5). MS m/z (%) 456 (M+,
0.12), 332 (20), 317 (10), 256 (30), 241 (87), 213 (14), 198 (34),
170 (26), 155 (19), 149 (10), 131 (33), 104 (61), 96 (32), 91 (64), 83
(100), 64 (57), 56 (36). Anal. Calcd for C21H14N12O2 (466.42) C, 54.08;
H, 3.02; N, 36.04. Found: C, 54.15; H, 3.10; N, 36.25%.
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3,4-Bis{([1,2,4]triazolo[3,4-c][1,2,4]triazin-6-yl)carbonyl)}-1-(4-
methoxyphenyl)-5-methylpyrazole (8c):Yellow solid, yield 2.04 g, (85
%), m.p. 136–138 °C, IR (KBr) νmax/cm−1 1676 (C=O), 1608(C=N),
1
1251(C–O–C). H NMR (DMSO-d6) δ = 3.50 (s, 3H, CH3), 3.83 (s,
3H, OCH3), 7.11 (d, J = 8.0 Hz, 2H, ArH), 7.49 (d, J = 8.0 Hz, 2H,
ArH), 7.53 (d, J = 8.0 Hz, 2H, ArH), 7.95 (s, 2H, H-3), 8.56 (d, J = 9.0
Hz, 2H, H-5). MS m/z (%) 482 (M+, 0.48), 272 (41), 257 (100), 214
(16), 187 (11), 172 (13), 148 (55), 122 (32), 118 (10), 113 (32), 105
16 C.J. Shishoo, M.B. Devani, G.V. Ullas, S. Ananthan and V.S. Bhadti,
J. Heterocycl. Chem., 1981, 18, 43.
17 HyperChemTM, Hypercube, Inc. 1115 NW 4th Street, Gainesville, Florida
32601, USA.

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