One-pot synthesis of 6H-pyrrolo[2,3-e[1,2,4]triazolo[1,5-a]pyrimidines on the basis of σh-adducts of 6-Nitro[1,2,4]triazolo[1,5-a] pyrimidine with carbonyl compounds

Article abstract of DOI:10.1134/s107042800801017x

Aromatic, heteroaromatic, and aliphatic carbonyl compounds reacted with 6-nitro[1,2,4]triazolo[1,5-a]pyrimidine in the presence of a base to give stable σ^H-adducts at C⁷. Reduction of the nitro group in the latter is accompanied by tandem autoaromatization of the azine ring and intramolecular cyclocondensation with formation of the corresponding 6H-pyrrolo[2,3-e][1,2,4]triazolo[1,5-a]pyrimidines.

Full text of DOI:10.1134/s107042800801017x

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 1, pp. 128–132. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © E.B. Gorbunov, G.L. Rusinov, R.I. Ishmetova, V.N. Charushin, O.N. Chupakhin, 2008, published in Zhurnal Organicheskoi Khimii,
2008, Vol. 44, No. 1, pp. 130–134.
Dedicated to Full Member of the Russian Academy of Sciences
G.A. Tolstikov on his 75th anniversary
One-Pot Synthesis of 6H-Pyrrolo[2,3-e][1,2,4]triazolo-
[1,5-a]pyrimidines on the Basis of σH-Adducts of 6-Nitro[1,2,4]-
triazolo[1,5-a]pyrimidine with Carbonyl Compounds
E. B. Gorbunov, G. L. Rusinov, R. I. Ishmetova, V. N. Charushin, and O. N. Chupakhin
Postovskii Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences,
ul. S. Kovalevskoi 20, Yekaterinburg, 620219 Russia
e-mail: charushin@htf.ustu.ru
Received July 17, 2007
Abstract—Aromatic, heteroaromatic, and aliphatic carbonyl compounds reacted with 6-nitro[1,2,4]triazolo-
[1,5-a]pyrimidine in the presence of a base to give stable σH-adducts at C7. Reduction of the nitro group in the
latter is accompanied by tandem autoaromatization of the azine ring and intramolecular cyclocondensation with
formation of the corresponding 6H-pyrrolo[2,3-e][1,2,4]triazolo[1,5-a]pyrimidines.
DOI: 10.1134/S107042800801017X
Important methods for building up fused pyrrole
derivatives are based on the use of nitro-substituted
aromatic and heteroaromatic compounds as starting
materials. These procedures include introduction of
an appropriate side chain into the ortho position with
respect to the nitro group, reduction of the latter to
amino, and cyclocondensation involving the amino
group and the side chain. The most general examples
of formation of pyrrole ring on the basis of nitroarenes
(hetarenes) are intramolecular reactions of the amino
group with electrophilic moiety of the side chain, e.g.,
carbonyl-containing group (Reissert reaction [1]) or
acetonitrile, nitroethylene [2, 3], and vinyl or acetylene
frgments [4].
participating in subsequent cyclizations, via nucleo-
philic attack on unsubstituted carbon atom. Such re-
actions were successfully performed on a series of SNH
products derived from nitroarenes with a view to syn-
thesize indole derivatives [6, 7], as well as on 3-nitro-
pyridines [8].
6-Nitroazolopyrimidines are capable of taking up
under mild conditions aromatic (N,N-dialkylanilines,
phenols, phenyl ethers) and heteroaromatic nucle-
ophiles (indoles, pyrroles) and anions derived from
some CH acids (methylazinium cations, malononitrile,
ethyl cyanoacetate, etc. [9]). In most cases, these
reactions stopped at the stage of formation of so stable
σH-adducts that their subsequent oxidative aromatiza-
tion was almost impossible.
Extensively developing approaches based on nucle-
ophilic substitution of hydrogen (SNH reactions) make it
possible to introduce into a nitroarene or hetarene
molecule various fragments, including those capable of
We briefly reported previously that σH-adducts de-
rived from 6-nitro[1,2,4]triazolo[1,5-a]pyrimidine (I)
undergo unexpected autoaromatization of the pyrimi-
Scheme 1.
Nu
N
H
Nu
H
Nu
H
Nu
H
NO2
N
NH
NH2
N
N
N
N
N
N
N
N
H+
[H]
N
N
OH
N
N
–H2O
–H2O
N
N
H
N
H
A
B
128

ONE-POT SYNTHESIS OF 6H-PYRROLO[2,3-e][1,2,4]TRIAZOLO[1,5-a]PYRIMIDINES
129
Scheme 2.
R
R
O
NH
NO2
NO2
N
N
N
N
N
N
O
Et3N
[H]
N
N
N
+
R
Me
IIa–IIf
N
N
N
H
I
IIIa–IIIf
IVa–IVf
R = 2-furyl (a), 2-thienyl (b), 2-(2-thienyl)ethenyl (c), PhCH=CH (d), 4-(ClCH2CH2)C6H4 (e), 3,4-CH2O2C6H4 (f).
dine ring in the course of reduction of the nitro group
[10]. It is known [5] that oxidative aromatization of
σH-adducts formed from dihydroazines, by contrast,
follows the SNH(AO) mechanism. Alternatives are elim-
ination mechanisms SNH(AE) implying assistance by
a readily departing group present in the substrate (tele
or cine substitution), introduced into the σH-adduct
with nucleophile (vicarious replacement), or formed
during the process. In our case we tend to prefer the
last version of cine substitution in hydroxylamine A
which is formed as intermediate in the course of the
reduction process (Scheme 1).
We found that 6-nitro[1,2,4]triazolo[1,5-a]pyrimi-
dine (I) reacts with methyl ketones IIa–IIf to give
stable adducts at C7 (compounds IIIa–IIIf) in high
yields (Scheme 2). The nitro group in σH-adducts IIIa–
IIIf can be reduced by the action of various reducing
agents, such as iron(II) hydroxide, tin(II) chloride,
sodium dithionite, and hydrogen over Pd/C catalyst.
The reduction is accompanied by aromatization of the
pyrimidine ring and intramolecular ring closure to
produce 6H-pyrrolo[2,3-e][1,2,4]triazolo[1,5-a]pyrimi-
dines IV (Scheme 2). The best results were obtained
using tin(II) chloride in the presence of concentrated
hydrochloric acid.
The presence in the resulting imine B molecule of
two potential reaction centers in the ortho position
with respect to each other creates favorable conditions
for subsequent heterocyclization. In the present work
we examined the possibility for synthesizing pyrrole-
fused systems on the basis of σH-adducts derived from
6-nitro[1,2,4]triazolo[1,5-a]pyrimidine (I) via reaction
with carbonyl compounds.
The structure of σH-adducts IIIa–IIIf was deter-
1
mined on the basis of their H NMR spectra and ele-
mental analyses. Compounds IIIa–IIIf characteristi-
1
cally showed in the H NMR spectra a signal from the
7-H proton as a triplet at δ 6.12–6.14 ppm, protons in
the exocyclic CH2 group resonated at δ 3.76–3.78 ppm
as a doublet of doublets, and the 5-H and 2-H signals
Scheme 3.
R3
N
O
N
N
O
N
N
Et3N
NO2
N
N
R2
I
+
N
N
R3
R1
R1
NH
N
R2
N
Va, Vb
VIa, VIb
R3
H
N
[H]
N
N
N
N
N
N
R1
N
N
R2
VIIa, VIIb
R1 = R2 = H, R3 = MeO (a); R1 = R2 = R3 = MeO (b).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 1 2008

GORBUNOV et al.
130
Scheme 4.
O
O
N
O
OH
NH
OH
NH
EtO
EtO
N
OEt
EtO
OEt
Et3N
SnCl2, HCl
KOH
I
+
NO2
N
N
N
N
N
N
O
O
N
N
H
N
N
VIII
IX
X
appeared as singlets at δ 8.37–8.39 and 7.77–7.78 ppm,
parative viewpoint, for it ensures one-pot transforma-
tion of σH-adducts III, VI, and VIII into the target
tricyclic structures, bypassing the oxidation step.
Moreover, high electrophilicity of initial 6-nitro[1,2,4]-
triazolo[1,5-a]pyrimidine (I) ensures its successful re-
actions with various nucleophiles, which considerably
extends the scope of application of the developed
procedure.
respectively. In addition, signals from protons in the
1
aryl substituent were present. The H NMR spectra of
tricyclic products IVa–IVf lacked 7-H signals, indicat-
ing that the pyrimidine ring therein is aromatic; the
8-H proton in the pyrrole ring gave a singlet at
δ 7.4 ppm, singlets at δ 8.52–8.69 and 8.87–9.07 ppm
were assigned to 2-H and 5-H, respectively, and sig-
nals from the substituent at C7 were observed.
EXPERIMENTAL
The proposed procedure is general; it ensures pyr-
role annulation with both bulkier polyfunctional car-
bonyl compounds, e.g., ketones V having a pharmaco-
phoric tetrazole fragment [11] (Scheme 3), and β-di-
carbonyl compounds, in particular diethyl malonate
(Scheme 4). Under the conditions analogous to the
synthesis of adducts IIIa–IIIf, the reactions of com-
pound I with ketones Va and Vb afforded stable σH-
adducts VIa and VIb whose reduction with tin(II)
chloride resulted in the formation of pyrrolotriazolo-
pyrimidines VIIa and VIIb, respectively in 35–36%
yield (Scheme 3). Compounds VIa and VIb displayed
The progress of reactions and the purity of products
were monitored by TLC on Armsorb KSGK-UF plates
using chloroform–methanol (9:1) as eluent; detection
1
under UV light. The H NMR spectra were measured
on a Bruker DRX-400 spectrometer (400 MHz) from
solutions in DMSO-d6 using tetramethylsilane as
internal reference. The elemental compositions were
determined on a Perkin–Elmer 240 automatic CHNO
analyzer. The melting points were determined on
a Boetius hot stage; uncorrected values are given.
1
in the H NMR spectra double sets of signals due to
7-Substituted 6-nitro-4,7-dihydro[1,2,4]triazolo-
[1,5-a]pyrimidines IIIa–IIIf, VIa, VIb, and VIII
(general procedure). A mixture of 1 mmol of triazolo-
pyrimidine I, 1 mmol of carbonyl compound Ia–If, Va,
or Vb or diethyl malonate, and 140 μl (1 mmol) of
triethylamine in 3 ml of acetonitrile was kept for 24 h
at room temperature. The mixture was acidified with
concentrated hydrochloric acid, and the precipitate was
filtered off, washed with distilled water and aceto-
nitrile, and dried in air.
the presence of mixtures of diastereoisomers: the 7-H
signals were observed as doublets at δ 6.44–6.33 ppm,
the 5-H and 2-H protons gave rise to two singlets at
δ 8.09–8.06 and 7.83–7.75, respectively, and the exo-
cyclic CH and CH2 protons resonated as multiplets at
δ 5.27–5.16 and 5.00–4.68 ppm, respectively; in addi-
tion, signals from protons in the aromatic rings were
1
present. The H NMR spectra of reduction products
VIIa and VIIb were considerably simpler, for their
molecules lack chiral centers; the spectra contained
a set of aromatic proton signals, singlets from 2-H and
5-H at δ 9.02–8.99 and 8.52–8.36 ppm, respectively,
and a two-proton singlet at δ 6.3 ppm, corresponding
to the CH2 group.
The reduction of adduct VIII obtained from com-
pound I and diethyl malonate gave ester IX, and alka-
line hydrolysis of IX, followed by decarboxylation,
lead to hydroxy derivative X (Scheme 4).
1-(2-Furyl)-2-(6-nitro-4,7-dihydro[1,2,4]triazolo-
[1,5-a]pyrimidin-7-yl)ethanone (IIIa). Yield 76%,
1
mp 236–238°C. H NMR spectrum, δ, ppm: 11.80 s
(NH), 8.26 s (5-H), 7.82 d.d (1H, Harom), 7.80 s (2-H),
7.27 d.d (1H, Harom), 6.58 d.d (1H, Harom), 6.05 t
(7-H), 3.55 d (2H, CH2). Found, %: C 47.90; H 3.48;
N 25.40. C11H9N5O4. Calculated, %: C 48.01; H 3.30;
N 25.45.
Thus the proposed procedure for the synthesis of
pyrrolotriazolopyrimidines is attractive from the pre-
2-(6-Nitro-4,7-dihydro[1,2,4]triazolo[1,5-a]pyri-
midin-7-yl)-1-(2-thienyl)ethanone (IIIb). Yield 71%,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 1 2008

ONE-POT SYNTHESIS OF 6H-PYRROLO[2,3-e][1,2,4]TRIAZOLO[1,5-a]PYRIMIDINES
131
1
mp 200–204°C. H NMR spectrum, δ, ppm: 11.83 s
(NH), 8.25 s (5-H), 7.85 d.d (1H, Harom), 7.79 s (2-H),
7.77 d.d (1H, Harom), 7.14 d.d (1H, Harom), 5.99 t (7-H),
3.66 d (2H, CH2). Found, %: C 45.28; H 3.12; N 24.10.
C11H9N5O3S. Calculated, %: C 45.36; H 3.11; N 24.04.
C 55.90; H 4.05; N 26.78. C22H19 N9O4. Calculated, %:
C 55.81; H 4.05; N 26.63.
3-[5-(3,4-Dimethoxyphenyl)-2H-tetrazol-2-yl]-
1-(3-methoxyphenyl)-2-(6-nitro-4,7-dihydro[1,2,4]-
triazolo[1,5-a]pyrimidin-7-yl)propan-1-one (VIb).
1
Yield 85%, mp 152–154°C. H NMR spectrum, δ,
1-(6-Nitro-4,7-dihydro[1,2,4]triazolo[1,5-a]pyri-
midin-7-yl)-4-(2-thienyl)but-3-en-2-one (IIIc). Yield
76%, mp 250–252°C. H NMR spectrum, δ, ppm:
11.81 s (NH), 8.26 s (5-H), 7.68 d.d (1H, Harom), 7.64 d
(1H, CH), 7.61 d.d (1H, Harom), 7.43 s (2-H), 7.09 d.d
(1H, Harom), 6.33 d (1H, CH), 5.98 t (7-H), 3.43 d
(2H, CH2). Found, %: C 49.22; H 3.44; N 22.15.
C13H11N5O3S. Calculated, %: C 49.21; H 3.49; N 22.07.
ppm: 11.95 s (NH), 8.06 s (1H, 5-H), 8.02 s (0.23H,
5-H), 7.98 d (2H, Harom), 7.75 t (1H, Harom), 7.53 d.d
(1H, Harom), 7.43 s (1H, 2-H), 7.40 s (0.26H, 2-H),
7.03 d (2H, Harom), 6.99–6.95 m (1H, Harom), 6.43 d
(1H, 7-H), 6.33 d (0.21H, 7-H), 5.18–5.17 m (1H,
CH), 5.02–4.97 m (1H, CH2), 4.73–4.68 (1H, CH2),
3.87 s (3H, CH3), 3.84 s (6H, CH3), 3.82 s (0.8H,
CH3), 3.79 s (0.7H, CH3). Found, %: C 53.97; H 4.40;
N 23.60. C24H23N9O6. Calculated, %: C 54.03; H 4.35;
N 23.63.
1
1-(6-Nitro-4,7-dihydro[1,2,4]triazolo[1,5-a]pyri-
midin-7-yl)-4-phenylbut-3-en-2-one (IIId). Yield
69%, mp 270–272°C. H NMR spectrum, δ, ppm:
12.19 s (NH), 8.25 s (5-H), 7.67 s (2-H), 7.58 d (1H,
CH), 7.50–7.47 m (1H, Harom), 7.34–7.30 m (2H,
Harom), 6.97–6.95 m (2H, Harom), 6.49 d (1H, CH),
5.99 t (7-H), 3.45 d (2H, CH2). Found, %: C 57.73;
H 4.22; N 22.55. C15H13N5O3. Calculated, %: C 57.88;
H 4.21; N 22.50.
1
Diethyl 2-(6-nitro-4,7-dihydro[1,2,4]triazolo-
[1,5-a]pyrimidin-7-yl)malonate (VIII). Yield 78%,
mp 145–147°C. Found, %: C 44.30; H 4.63; N 21.54.
C12H15N5O6. Calculated, %: C 44.31; H 4.65; N 21.53.
7-Substituted pyrrolo[2,3-e][1,2,4]triazolo[1,5-a]-
pyrimidines IVa–IVf, VIIa, VIIb, and IX (general
procedure). A solution of 290 mg of tin(II) chloride
dihydrate in 2 ml of acetic acid and 250 μl of con-
centrated hydrochloric acid were added under stirring
to a solution of 100 mg of compound IIIa–IIIf, VIa,
VIb, or VIII in 3 ml of acetic acid. The precipitate was
filtered off, washed with distilled water, and dissolved
in DMF, the solution was applied to aluminum oxide,
the product was washed off with chloroform–ethanol
(3:1), and the filtrate was evaporated.
1-[4-(2-Chloroethyl)phenyl]-2-(6-nitro-4,7-dihy-
dro[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)ethanone
(IIIe). Yield 77%, mp 230–234°C. 1H NMR spectrum,
δ, ppm: 11.78 s (NH), 8.23 s (5-H), 7.67 s (2-H),
7.87 d (2H, Harom), 7.66 d (2H, Harom), 5.91 t (7-H),
4.33 t (2H, CH2), 3.38 d (2H, CH2), 3.34 t (2H, CH2).
Found, %: C 51.71; H 4.06; N 20.15. C15H14ClN5O3.
Calculated, %: C 51.81; H 4.06; N 20.14.
1-(1,3-Benzodioxol-5-yl)-2-(6-nitro-4,7-dihydro-
7-(2-Furyl)-6H-pyrrolo[2,3-e][1,2,4]triazolo-
[1,5-a]pyrimidine (IVa). Yield 34%, mp > 300°C.
1H NMR spectrum, δ, ppm: 13.13 s (NH), 8.95 s (5-H),
8.54 s (2-H), 7.85 s (8-H), 7.26–7.22 m (2H, Harom),
7.61–4.76 m (1H, Harom). Found, %: C 58.59; H 3.10;
N 31.02. C11H7N5O. Calculated, %: C 58.67; H 3.13;
N 31.02.
[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)ethanone (IIIf).
1
Yield 51%, mp 238–240°C. H NMR spectrum, δ,
ppm: 11.89 s (NH), 8.37 s (5-H), 7.77 s (2-H), 7.82 d
(1H, Harom), 7.67–7.65 m (2H, Harom), 6.12 t (7-H),
4.33 t (2H, CH2), 5.98 s (2H, CH2). Found, %:
C 51.00; H 3.40; N 21.23. C14H11 N5O5. Calculated, %:
C 51.07; H 3.37; N 21.23.
7-(2-Thienyl)-6H-pyrrolo[2,3-e][1,2,4]triazolo-
[1,5-a]pyrimidine (IVb). Yield 37%, mp > 300°C.
1H NMR spectrum, δ, ppm: 13.18 s (NH), 8.94 s (5-H),
8.52 s (2-H), 7.62 d.d (1H, Harom), 7.30 s (8-H), 7.18–
7.12 m (2H, Harom). Found, %: C 54.70; H 3.00;
N 29.00. C11H7N5S. Calculated, %: C 54.76; H 2.92;
N 29.03.
1-(3-Methoxyphenyl)-2-(6-nitro-4,7-dihydro-
[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)-3-(5-phenyl-
2H-tetrazol-2-yl)propan-1-one (VIa). Yield 78%,
1
mp 234–235°C. H NMR spectrum, δ, ppm: 12.00 s
(NH), 8.09 s (1H, 5-H), 8.02 s (0.75H, 5-H), 7.99–
7.97 m (3H, Harom, 2-H), 7.92 d (1.55H, Harom), 7.83 s
(0.72H, 2-H), 7.74 d (2H, Harom), 7.49–7.45 m (5H,
7-[2-(2-Thienyl)vinyl]-6H-pyrrolo[2,3-e][1,2,4]-
triazolo[1,5-a]pyrimidine (IVc). Yield 32%, mp >
H
arom), 7.02 d (2H, Harom), 6.96 d (1.51H, Harom), 6.44 d
1
(1H, 7-H), 6.33 d (0.73H, 7-H), 5.21–5.18 m (1H,
CH), 5.03–4.98 m (1H, CH2), 4.76–4.75 (1H, CH2),
3.87 s (3H, CH3), 3.84 s (2.24H, CH3). Found, %:
300°C. H NMR spectrum, δ, ppm: 12.74 s (NH),
8.94 s (5-H), 8.50 s (2-H), 8.78 d (1H, CH), 7.62 d.d
(1H, Harom), 7.34 s (8-H), 7.16–7.14 m (2H, Harom),
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GORBUNOV et al.
132
7.07 d (1H, CH). Found, %: C 58.36; H 3.34; N 26.11.
C13H9N5S. Calculated, %: C 58.41; H 3.39; N 26.20.
CH3), 1.16 t (3H, CH3). Found, %: C 48.50; H 3.59;
N 28.34. C24H21N9O3. Calculated, %: C 48.59; H 3.67;
N 28.33.
7-(2-Phenylethenyl)-6H-pyrrolo[2,3-e][1,2,4]-
triazolo[1,5-a]pyrimidine (IVd). Yield 38%, mp >
7-Hydroxy[1,2,4]triazolo[1,5-a]pyrrolo[2,3-e]-
pyrimidine (X). A mixture of 1 mmol of ester IX and
a 2 M solution of potassium hydroxide was heated for
30 min at the boiling point. The mixture was cooled
and neutralized with acetic acid, and the precipitate
was filtered off, repeatedly washed with water, and
1
300°C. H NMR spectrum, δ, ppm: 13.18 s (NH),
8.93 s (5-H), 7.49 s (2-H), 7.82 d (2H, Harom), 7.76 d
(2H, Harom), 7.10 s (8-H), 3.38 d (2H, CH2), 3.34 t (2H,
CH2). Found, %: C 69.03; H 4.21; N 26.83. C15H11N5.
Calculated, %: C 68.95; H 4.24; N 26.83.
1
dried in air. Yield 67%, mp > 300°C. H NMR spec-
7-[4-(2-Chloroethyl)phenyl]-6H-pyrrolo[2,3-e]-
[1,2,4]triazolo[1,5-a]pyrimidine (IVe). Yield 34%,
trum, δ, ppm: 12.74 s (NH), 10.27 s (OH), 8.27 s
(5-H), 7.31 s (2-H), 5.55 s (8-H). Found, %: C 48.09;
H 2.99; N 39.97. C7H5N5O. Calculated, %: C 48.00;
H 2.88; N 39.98.
1
mp > 300°C. H NMR spectrum, δ, ppm: 13.04 s
(NH), 9.00 s (5-H), 8.68 s (2-H), 7.58–7.56 m (2H,
H
arom), 7.17 s (8-H), 7.39–7.37 m (3H, Harom), 7.49 d
(1H, CH), 6.65 d (1H, CH). Found, %: C 60.46;
H 4.00; N 23.48. C15H12ClN5. Calculated, %: C 60.51;
H 4.00; N 23.48
This study was performed under financial support
by the Russian Foundation for Basic Research (project
nos. 06-03-08141-ofi, 07-03-12112-ofi, 07-03-96113-
r_urala, 07-03-96123-r_urala) and by the Ministry
of Industry and Science of the Russian Federation
(project no. NSh-9178.2006.3).
7-(1,3-Benzodioxol-5-yl)-6H-pyrrolo[2,3-e]-
[1,2,4]triazolo[1,5-a]pyrimidine (IVf). Yield 34%,
1
mp > 300°C. H NMR spectrum, δ, ppm: 13.03 s
(NH), 8.82 s (5-H), 7.79 d (1H, Harom), 7.70 s (2-H),
7.62–7.59 m (2H, Harom), 5.98 s (2H, CH2). Found, %:
C 60.15; H 3.30; N 25.10. C14H9N5O2. Calculated, %:
C 60.21; H 3.25; N 25.10.
REFERENCES
1. Julien, P., Meier, E., and Rinti, E., Heterocyclic
Compounds, Elderfield, R.C., Ed., New York: Wiley,
1952, vol. 3. Translated under the title Geterotsik-
licheskie soedineniya, Moscow: Inostrannaya Literatura,
1954, vol. 3, p. 5.
7-(4-Methoxyphenyl)-8-(5-phenyl-2H-tetrazol-
2-ylmethyl)-6H-pyrrolo[2,3-e][1,2,4]triazolo[1,5-a]-
pyrimidine (VIIa). Yield 36%, mp 264–266°C.
1H NMR spectrum, δ, ppm: 13.03 s (NH), 8.82 s (5-H),
7.79 d (1H, Harom), 7.70 s (2-H), 7.62–7.59 m (2H,
2. Kruse, L.I., Heterocycles, 1981, vol. 16, p. 1119.
3. Macor, J.E. and Wehner, J.M., Tetrahedron, 1991,
p. 7195.
H
arom), 5.98 s (2H, CH2). Found, %: C 62.36; H 4.00;
N 25.79. C22H17N9O. Calculated, %: C 62.40; H 4.05;
N 29.79.
4. Rudisill, D.E. and Stille, J.K., J. Org. Chem., 1989,
vol. 54, p. 5856.
5. Chupakhin, O.N., Charushin, V.N., and van der
Plas, H.C., Nucleophilic Aromatic Substitution of
Hydrogen, San Diego: Academic, 1994.
6. Makosza, M. and Wojciechowski, K., Chem. Rev., 2004,
vol. 104, p. 2631.
7. Rajan Babu, T.V., Chenard, B.L., and Petti, M.A.,
J. Org. Chem., 1986, vol. 51, p. 1704
8. Andreassen, E.J. and Bakke, J.M., J. Heterocycl. Chem.,
2006, vol. 43, p. 49.
9. Rusinov, V.L. and Chupakhin, O.N., Nitroaziny (Nitro-
8-[5-(3,4-Dimethoxyphenyl)-2H-tetrazol-2-yl-
methyl]-7-(4-methoxyphenyl)-6H-pyrrolo[2,3-e]-
[1,2,4]triazolo[1,5-a]pyrimidine (VIIb). Yield 40%,
mp > 300°C. H NMR spectrum, δ, ppm: 13.00 s
(NH), 9.03 s (5-H), 8.52 s (2-H), 7.75 d (2H, Harom),
7.51 d.d (1H, Harom), 7.44 d (1H, Harom), 7.16 d (2H,
1
H
arom), 7.07 d (1H, Harom), 6.39 s (2H, CH2), 3.85 s
(3H, CH3), 3.80 s (3H, CH3), 3.79 s (3H, CH3). Found,
%: C 48.50; H 3.59; N 28.34. C24H21N9O3. Calculated,
%: C 48.59; H 3.67; N 28.33.
azines), Novosibirsk: Nauka, 1991.
Ethyl 7-hydroxy-6H-pyrrolo[2,3-e][1,2,4]tri-
azolo[1,5-a]pyrimidine-8-carboxylate (IX). Yield
40%, mp > 300°C. 1H NMR spectrum, δ, ppm: 13.00 s
(NH), 9.03 s (5-H), 8.32 s (2-H), 6.22 d (7-H), 4.23–
4.12 q (2H, CH2), 4.07–4.00 q (2H, CH2), 1.30 t (3H,
10. Rusinov, G.L., Gorbunov, E.B., Charushin, V.N., and
Chupakhin, O.N., Tetrahedron Lett., 2007, vol. 48,
p. 5873.
11. Rusinov, G.L., Ishmetova, R.I., and Chupakhin, O.N.,
Russ. J. Org. Chem., 1997, vol. 33, p. 524.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 1 2008