Substitution for a nitro group in 1,3,5-trinitrobenzene under the action of NH-azoles

Article abstract of DOI:10.1070/MC2001v011n06ABEH001481

Conditions under which a nitro group in 1,3,5-trinitrobenzene is replaced under the action of NH-azoles were found.

Full text of DOI:10.1070/MC2001v011n06ABEH001481

, 2001, 11(6), 232–233
Substitution for a nitro group in 1,3,5-trinitrobenzene under the action of NH-azoles
Oleg Yu. Sapozhnikov, Mikhail D. Dutov, Maksim A. Korolev, Vadim V. Kachala and Svyatoslav A. Shevelev*
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
Fax: +7 095 135 5328; e-mail: Shevelev@ioc.ac.ru
10.1070/MC2001v011n06ABEH001481
Conditions under which a nitro group in 1,3,5-trinitrobenzene is replaced under the action of NH-azoles were found.
As a continuation of our studies1,2 devoted to the conversion of
N
aromatic explosives, we examined the reaction of 1,3,5-trinitro-
benzene with NH-azoles.
O2N
N
N
NH
NH
N
3a
By now, the formation of stable anionic σ-complexes as a
result of reactions between nitrogen-containing heterocycles such
as pyrrole, indole and imidazole with 1,3,5-trinitrobenzene (TNB)
is well known.3–5 The kinetics of formation of these adducts
was thoroughly studied. Initially, N-σ-complex 1 is rapidly
formed; next, it undergoes rearrangement to more stable C-σ-
complex 2 (Scheme 1). Some of these intermediates can be
isolated as pure compounds. The products with replaced nitro
groups were not reported.
N
N
N
N
O2N
O2N
4a
4b
3b
NO2
O2N
O2N
i
O2N
O2N
NO2
H
N
MeOK, DMSO
NH
NO2
NO2
O2N
N
N
N
NH
O2N
N
N
O2N
3c
NO2
4c
1
HN
O2N
N
N
H
NO2
O2N
N
O2N
O2N
5
NO2
N
2
N
NH
N
Scheme 1
3d
N
On the other hand, it was found2,6–8 that, in principle, a nitro
group in TNB can be replaced under the action of O- anf S-
anionic nucleophiles with good yields.
N
O2N
4d
We decided on compounds containing the =N–N(H)– unit,
in particular, pyrazole, 1,2,3-triazole, 1,2,4-triazole and benzo-
triazole, as NH-azoles. The reactions of these heterocycles (3a–d)
with TNB were examined under various conditions. The pro-
ducts of substitution for a nitro group were formed on heating
in amide dipolar aprotic solvents (such as DMF and N-methyl-
2-pyrrolidone) in the presence of K2CO3 (Scheme 2, Table 1).†
The lowest yield and the longest reaction time were observed
in the case of pyrazole. In the case of benzotriazole, two pro-
ducts 4c and 5 were formed in overall yield 96%. Recrystal-
lization from DMF gave rise to isomer 5. Mother liquor was
evaporated, and the residue was recrystallised from dioxane to
give isomer 4c. Using 1H NMR spectroscopy, we found the 4c/5
ratio between these isomers to be equal to 2/3 and characterised
Scheme 2 Reagents and conditions: i, N–MP, 80 °C, K2CO3.
system and appear as two doublets and two triplets (a doublet of
doublets) in the 1H NMR spectrum.† The NOE interaction with
a doublet at 8.25 ppm was observed on irradiation of H(2') and
H(6') protons. On this basis, we concluded that this signal is
ascribed to H(7) proton. Next, the other protons of the benzo-
triazole nucleus were identified using a double resonance tech-
nique. The predominance of an isomer substituted at the 2-posi-
tion of the benzotriazole ring is not typical of the arylation of
benzotriazole, and it probably results from the electrophilic pro-
perties of TNB. In the case of 1,2,3-triazole, only compound
4d, which is the product of substitution at the 2-position of the
triazole nucleus, was formed.
1
the structure of these compounds. The H NMR spectrum of
compound 5 exhibits two multiplets with the integral intensity
2H in the region 7–9 ppm, which correspond to a symmetrically
substituted benzotriazole. The protons of the benzene ring in
asymmetrically substituted benzotriazole 4c form an ABCD spin
This work was supported by the International Science and
Technology Centre (grant no. 419).
References
Table 1 Reaction of 3a–d with TNB.
1 V. A. Tartakovsky, S. A. Shevelev, M. D. Dutov, A. Kh. Shakhnes, A. L.
Rusanov, L. G. Komarova and A. M. Andrievsky, in Conversion Concepts
for Commercial Applications and Disposal Technologies of Energetic
Systems, ed. H. Krause, Kluwer Academic Publishers, Dordrecht, 1997,
p. 137.
2 O. V. Serushkina, M. D. Dutov and S. A. Shevelev, Izv. Akad. Nauk, Ser.
Khim., 2001, 252 (Russ. Chem. Bull., 2001, 50, 261).
3 F. Terrier, F. Debleds, J. Halle and M. Simonnin, Tetrahedron Lett., 1982,
23, 4079.
Reaction
time/h
Solvent for
recrystallization
Product
Yield (%)
mp/°C
4a
4b
4c
5
30
6
4
4
2.5
20
75
10
45
71
112–114
131–133
184–186
213–214
126–128
CHCl3
CHCl3
Dioxane
DMF
4d
EtOH
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, 2001, 11(6), 232–233
4 M. Simonnin, F. Terrier, M. Pouet and J. Halle, Can. J. Chem., 1985, 866.
5 F. Terrier, F. Debledts, J. Halle, M. Simonnin and M. Pouet, Can. J.
Chem., 1982, 1988.
6 S. A. Shevelev, M. D. Dutov, I. A. Vatsadze, O. A. Serushkina, A. L.
Rusanov and A. M. Andrievskii, Mendeleev Commun., 1995, 157.
7 S. A. Shevelev, M. D. Dutov, I. A. Vatsadze, M. A. Korolev and A. L.
Rusanov, Mendeleev Commun., 1996, 155.
8 S. A. Shevelev, M. D. Dutov, M. A. Korolev, O. Yu. Sapozhnikov and
A. L. Rusanov, Mendeleev Commun., 1998, 69.
†
1H and 13C NMR spectra were measured on a Bruker AM-300 instru-
ment using [2H6]DMSO as a solvent and TMS as a standard. Peaks due
+
·
to molecular ions (M ) were present in the mass spectra of all com-
pounds synthesised. The spectra were obtained on an MS-30 (Kratos)
(EI, 70 eV) spectrometer. The structure of products were confirmed by
elemental analysis.
General procedure for the reaction of NH-azoles with 1,3,5-trinitro-
benzene. A mixture of TNB (0.01 mol), an NH-azole (0.01 mol) in 20 ml
of N-methyl-2-pyrrolidone was heated at 80 °C for the time specified in
Table 1 (until the disappearance of TNB). After completion of the reac-
tion, the mixture was poured into water. The precipitate formed was
washed several times with dilute hydrochloric acid and dried. The com-
pounds were purified by recrystallization.
1
1-(3,5-Dinitrophenyl)-1,2,4-triazole 4a: H NMR, d: 9.70 (s, 1H, H-
5), 9.05 (d, 2H, H-2',6', 4J 2.0 Hz), 8.81 (s, 1H, H-4', 4J 2.0 Hz), 8.33 (s,
1H, H-3). 13C NMR, d: 116.6 [s, C(4')], 119.2 [s, C(2')], 138.0 [s, C(1')],
143.8 [s, C(5)], 148.8 [s, C(3')], 153.1 [s, C(3)].
1-(3,5-Dinitrophenyl)pyrazole 4b: 1H NMR, d: 9.05 (d, 2H, H-2',6', 4J
2.0 Hz), 8.95 (d, 1H, H-3, 3J 2.7 Hz), 8.71 (t, 1H, H-4', 4J 1.9 Hz), 7.89
(d, 1H, H-5, 3J 1.7 Hz), 6.72 (t, 1H, H-4, 3J 2.8 Hz). 13C NMR, d: 109.6
[s, C(4)], 114.8 [s, C(4')], 117.7 [s, C(2')], 129.3 [s, C(5)], 140.8 [s,
C(1')], 143.0 [s, C(3)], 148.8 [s, C(3')].
1-(3,5-Dinitrophenyl)benzotriazole 4c: 1H NMR, d: 9.05 (d, 2H, H-2',6',
4
3
4J 1.9 Hz), 8.95 (t, 1H, H-4', J 1.9 Hz), 8.25 (d, 1H, H-7, J 7.9 Hz),
8.10 (d, 1H, H-4, 3J 7.7 Hz), 7.81 (t, 1H, H-5, 3J 8.1 Hz), 7.62 (t, 1H, H-6,
3J 8.0 Hz). 13C NMR, d: 111.0 [s, C(7)], 117.9 [s, C(4')], 120.1 [s, C(4)],
123.2 [s, C(2')], 125.5 [s, C(5)], 129.7 [s, C(6)], 131.9 [s, C(3a)], 137.6
[s, C(1')], 145.9 [s, C(7a)], 148.9 [s, C(3')].
2-(3,5-Dinitrophenyl)benzotriazole 5: 1H NMR, d: 9.25 (d, 2H, H-2',6',
4J 2.0 Hz), 8.92 (t, 1H, H-4', 4J 2.0 Hz), 8.05 (dd, 2H, H-4,7, 3J 6.6 Hz,
3J 7.3 Hz), 7.58 (dd, 2H, H-5,6, 3J 6.6 Hz, 3J 7.3 Hz). 13C NMR, d:
118.2 [s, C(4')], 118.5 [s, C(4)], 120.0 [s, C(2')], 129.1 [s, C(5)], 140.3
[s, C(1')], 145.1 [s, C(3a)], 148.9 [s, C(3')].
2-(3,5-Dinitrophenyl)-1,2,3-triazole 4d: 1H NMR, d: 8.98 (d, 2H, H-2',6',
4J 1.9 Hz), 8.82 (t, 1H, H-4', 4J 1.9 Hz), 8.33 (s, 2H, H-4,5). 13C NMR,
d: 149.4 [s, C(3')], 140.3 [s, C(1')], 139.0 [s, C(4)], 118.6 [s, C(2')],
117.1 [s, C(4')].
Received: 25th May 2001; Com. 01/1807
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