Studies on substitution of nitro groups in 1,3,5-trinitrobenzene with NH-azoles

Article abstract of DOI:10.1023/B:RUCB.0000035643.20384.a0

Conditions were found under which NH-azoles (benzotriazole and its derivatives, 1,2,3- and 1,2,4-triazoles, pyrazole and its derivatives) replace one nitro group in 1,3,5-trinitrobenzene (TNB) to form the corresponding N-(3,5-dinitrophenyl)azoles in the presence of inorganic bases in aprotic dipolar solvents. The reaction pathway was found to depend on the structure of the starting azole. The benzotriazolyl and 1,2,4-triazolyl fragments activate the replacement of the meta-nitro group to virtually the same extent as the nitro group in TNB, which made it possible to successively replace all three nitro groups in TNB.

Full text of DOI:10.1023/B:RUCB.0000035643.20384.a0

588
Russian Chemical Bulletin, International Edition, Vol. 53, No. 3, pp. 588—595, March, 2004
Studies on substitution of nitro groups in 1,3,5ꢀtrinitrobenzene
with NHꢀazoles*
O. Yu. Sapozhnikov, M. D. Dutov, M. A. Korolev, V. V. Kachala, V. I. Kadentsev, and S. A. Shevelevꢀ
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5328. Eꢀmail: shevelev@ioc.ac.ru
Conditions were found under which NHꢀazoles (benzotriazole and its derivatives, 1,2,3ꢀ and
1,2,4ꢀtriazoles, pyrazole and its derivatives) replace one nitro group in 1,3,5ꢀtrinitrobenzene
(TNB) to form the corresponding Nꢀ(3,5ꢀdinitrophenyl)azoles in the presence of inorganic
bases in aprotic dipolar solvents. The reaction pathway was found to depend on the structure of
the starting azole. The benzotriazolyl and 1,2,4ꢀtriazolyl fragments activate the replacement of
the metaꢀnitro group to virtually the same extent as the nitro group in TNB, which made it
possible to successively replace all three nitro groups in TNB.
Key words: 1,3,5ꢀtrinitrobenzene, NHꢀazoles, nucleophilic substitution of a nitro group,
Nꢀ(3,5ꢀdinitrophenyl)azoles, bisꢀ and trisꢀazolylbenzenes.
Scheme 1
1,3,5ꢀTrinitrobenzene (TNB) serves as a convenient
model for studying the competition between the nucleoꢀ
philic substitution of an aromatic nitro group and the
addition of nucleophiles to the aromatic ring. Actually,
the characteristic feature of TNB is its ability to add nuꢀ
cleophiles at the ortho position with respect to the nitro
group to form stable anionic σꢀcomplexes.3—6 However,
conditions under which certain anionic Oꢀ and Sꢀnucleoꢀ
philes can replace one or two nitro groups in TNB have
been found in recent years (see, for example, Refs. 7—11).
It should be emphasized that all types of products preꢀ
pared by the replacement of the nitro groups in TNB have
previously been inaccessible. Therefore, investigations into
nucleophilic substitution in TNB are also of preparative
interest.
The reactions of TNB with NHꢀazoles, such as pyrꢀ
role, indole, and imidazole, studied earlier12—14 afꢀ
forded stable anionic σꢀcomplexes as the only products
(Scheme 1). The kinetics of the formation of these adꢀ
ducts was investigated in detail. The first step of the reacꢀ
tion involves the formation of Nꢀσꢀcomplex 1, which is
rearranged into more stable Cꢀσꢀcomplex 2. Some of these
compounds can be isolated in the individual form. In the
cited studies, no substitution products of the nitro groups
were documented.
We chose benzotriazole (BT) as the first NHꢀazole to
examine the possibility of the substitution of nitro groups
in TNB. One of the reasons for this choice is that this
compound is devoid of CH fragments adjacent to the
nitrogen atoms, which prevents formation of complexes
of type 2. In addition, an analysis of publications devoted
to the substitution of the nitro groups in TNB with
phenols7 and polyfluorinated alcohols8 shows that the
acidity of the starting nucleophile plays a significant role
in this process. Generally, the acidity pKa(H O) ≈ 8—12.5
2
is required. Benzotriazole satisfies this requirement
(pKa(H O) = 8.2).
We2found that benzotriazole (or its K salt (KꢀBT)15
)
replaces one nitro group in TNB in dipolar aprotic solꢀ
vents (DMF, Nꢀmethylpyrrolidone (NꢀMP), DMSO, or
MeCN) in the presence of alkalis or alkali metal carbonꢀ
ates at 80 °C. In the absence of bases, no reaction occurs.
Solid K2CO3 in NꢀMP is a reagent of choice from both
the viewpoint of the yields of the target products (Table 1)
1
* For preliminary communications, see Refs. 1 and 2.
and the ease of their isolation. Analysis of the H NMR
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 561—568, March, 2004.
1066ꢀ5285/04/5303ꢀ0588 © 2004 Plenum Publishing Corporation

Substitution of nitro groups in trinitrobenzene
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 3, March, 2004
589
Table 1. Influence of the reaction conditions on the reaction
rate and yields of products for the reaction of BT with TNB in
the presence of bases (1 : 1 : 1) at 80 °C
azole 3, the protons of the benzene ring form an ABCD
spin system and are observed in the 1H NMR spectrum as
two doublets and two triplets (doublets of doublets). Irraꢀ
diation of the H(2´) and H(6´) protons results in the NOE
effect with a doublet at δ 8.25, which indicates that this
proton is located at position 7. The signals for other proꢀ
tons of the benzotriazole moiety were assigned using the
double resonance technique. The mass spectrum of comꢀ
pound 3 has the characteristic peak [M – 28]+ associated
with the elimination of the nitrogen molecule.
Earlier, compound 3 has been prepared by the addiꢀ
tion of 3,5ꢀdinitrophenylazide to dehydrobenzene.20
However, the melting point of the reaction product reꢀ
ported in the cited study is 14 °C lower than that deterꢀ
mined in our investigation.
Base
Solvent τ*/h Yield of a mixture of
isomers 3 and 4 (%)
Isomer
ratio (3/4)
K2СО3 NꢀMP
K2СО3 DMF
K2СО3 DMSO
K2СО3 MeCN
KꢀBT** NꢀMP
Na2СО3 NꢀMP
Cs2СО3 NꢀMP
Li2СО3 NꢀMP
4
3
6
5
3
4
7
16
8
96
85
81
78
92
90
77
75
76
40/60
44/56
40/60
42/58
40/60
40/60
42/58
46/54
39/61
KOH
NꢀMP
K2СО3 EtOH
K2СО3 Dioxane
No reaction
No reaction
We also studied the nucleophilic substitution of nitro
groups in TNB under the action of 5ꢀsubstituted benzoꢀ
triazoles (5ꢀXꢀBT). We chose 5ꢀsubstituted benzotriazoles
with the aim of excluding the influence of steric factors on
the isomer ratio.
* The conversion time of TNB.
** K salt of BT.
spectra of the reaction products demonstrated that the
reactions always afforded isomeric 1ꢀ and 2ꢀ(3,5ꢀdinitroꢀ
phenyl)benzotriazoles 3 and 4 in a ratio of ≈2 : 3
(Scheme 2, see Table 1).
The reaction was carried out under the conditions
analogous to those used in the reaction with benzotriazole,
viz., heating in NꢀMP at 80 °C in the presence of an
equimolar amount of potassium carbonate (Scheme 3).
Waterꢀinsoluble reaction products prepared in the anaꢀ
1
lytically pure form were studied by H NMR spectrosꢀ
Scheme 2
copy. These spectra were compared with those of comꢀ
Scheme 3
i. NꢀMP, 80 °C, K2CO3.
Our results differ substantially from those obtained
earlier in the studies of arylation of benzotriazoles with
halonitrobenzenes,16,17 including arylation with the use
of Pdꢀ and Cuꢀcontaining catalysts,18,19 where N(1) isoꢀ
mers always predominated.
Isomers 3 and 4 were separated by either column chroꢀ
matography or crystallization from DMF or DMSO, the
solubility of isomer 3 being much higher than that of 4.
The structures of the isomers were established by 1H NMR
spectroscopy. The spectrum of compound 4 has two douꢀ
blets of doublets at δ 7.6—8.2 with integral intensities of
2 H each. In nonꢀsymmetrically substituted benzotriꢀ
X = Cl (a), Br (b), CF3 (c), OMe (d)
i. NꢀMP, 80 °C, K2CO3.

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Russ.Chem.Bull., Int.Ed., Vol. 53, No. 3, March, 2004
Sapozhnikov et al.
Table 2. Reaction of 5ꢀXꢀBT with TNB in the presence of K2CO3
(1 : 1 : 1) in NꢀMP at 80 °C
presence of an equimolar amount of K2CO3), 1,2,3ꢀtriꢀ
azole gave two products. Judging from the presence, in
the mixture, of two types of signals in the 1H NMR specꢀ
tral region typical of the dinitrophenyl group, the reaction
produced isomeric compounds 10 and 11 in a ratio of 1 : 9
(the conversion time of TNB was 2.5 h)* (Scheme 5). The
major isomer was isolated by crystallization from ethanol.
Х
τ*/h
Yield (%)
Isomer ratio (5+6)/7
Cl
Br
CF3
OMe
2.5
4.5
5
90
94
93
83
31/69
33/67
20/80
30/70
1
The H NMR spectrum of this compound has a singlet
8
with a double intensity corresponding to the equivalent
protons of the 1,2,3ꢀtriazole ring. The mass spectrum of
this compound does not show a peak at m/z [M – 28]
characteristic of N(1)ꢀarylated 1,2,3ꢀtriazoles, which conꢀ
firms its structure as 2ꢀ(3,5ꢀdinitrophenyl)ꢀ1,2,3ꢀtriꢀ
azole 11. Therefore, the percentage of the 3,5ꢀdinitroꢀ
phenylation product at position 2 of the triazole ring
sharply increases on going to 1,2,3ꢀtriazole from its
benzoannelated analog.
* The conversion time of TNB.
pounds 3 and 4. A set of signals for the protons of the
benzotriazole moiety in the 1H NMR spectra is indicative
of the formation of isomers 5—7. Two groups of signals of
the dinitrophenyl fragment of the molecule are evidence
for the formation of N(1)ꢀ and N(2)ꢀsubstitution prodꢀ
ucts, which allowed us to determine the ratios between
these products (see Table 2). In all cases, product 7 was
isolated in the pure form. The results are given in Table 2.
The introduction of a substituent into benzotriazole
leads to an increase in the percentage of the N(2) isomer,
which is most pronounced for the CF3 group.
Scheme 5
The possibility of the substitution of the nitro group in
TNB analogs under the action of benzotriazole was exꢀ
amined using the reaction of 1,3ꢀdinitroꢀ5ꢀtrifluoroꢀ
methylbenzene in NꢀMP in the presence of an equimolar
amount of K2CO3 (Scheme 4).
Scheme 4
i. NꢀMP, 80 °C, K2CO3.
The results of our study demonstrate that a high deꢀ
gree of N(2)ꢀarylation of benzotriazoles and 1,2,3ꢀtriazole
is a specific feature of TNB as an electrophile.
1,2,4ꢀTriazole also substitutes a nitro group in TNB
on heating in NꢀMP at 80 °C in the presence of an equimoꢀ
lar amount of K2CO3 to give exclusively isomer 12 (the
yield was 75%, the conversion time of TNB was 6 h)
(Scheme 6).
The observed direction of 3,5ꢀdinitrophenylation of
1,2,4ꢀtriazole at position 1 is consistent with the pubꢀ
lished data on arylation of 1,2,4ꢀtriazole.
Unsubstituted pyrazole exhibits lower reactivity in the
reaction with TNB (Scheme 7). Thus the reactions with
benzotriazole, 1,2,3ꢀtriazole, and 1,2,4ꢀtriazole were
completed in 4—8 h (the time of complete conversion of
i. NꢀMP, 80 °C, K2CO3.
As expected, the reaction afforded two isomers, 8
and 9, in a ratio of 45 : 55 (judging from the H NMR
spectroscopic data for the crude product).
It was of interest to compare the behavior of benzoꢀ
triazole and 1,2,3ꢀtriazole, which would allow us to reveal
the influence of the annelated benzene ring on the proꢀ
cess under study.
Under the conditions optimum for the reaction of
benzotriazole with TNB (heating in NꢀMP at 80 °C in the
1
* In all cases, equal concentrations of reactants were used to
compare different experiments with regard to the conversion
times of the starting material.

Substitution of nitro groups in trinitrobenzene
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 3, March, 2004
591
Scheme 6
slow rate of the reaction of TNB with pyrazole. The low
yield of the product of this reaction can be rationalized
considering possible thermal decomposition of the comꢀ
plex at the reaction temperature, like that of any salt of an
alicyclic nitro compound.
Actually, the reactions of TNB with 4ꢀbromopyrazole
(pKa(H O) = 12.69) and 4ꢀchloropyrazole (possessing simiꢀ
2
lar pKa(H O)) afforded substitution products 13b,c in yields
2
above 70%, and the reaction time was no longer than 6 h.
Under the aboveꢀmentioned conditions, 3,5ꢀdimethylꢀ
pyrazole (pKa(H O) = 15.8) does not react with TNB. Atꢀ
2
tempts to replace a nitro group in TNB under the action
of imidazole or various benzoimidazoles also failed.
The results of the study demonstrated that a nitro
group in TNB is replaced only with NHꢀazoles in which
azolate anions contain at least two adjacent nitrogen atꢀ
oms. Apparently, high nucleophilicity of such compounds
in the substitution of nitro groups in TNB is associated
with the soꢀcalled αꢀeffect, viz., the presence of pꢀ and/or
πꢀelectrons on the atom adjacent to the reaction center21
(in the case under consideration, on the nitrogen atom).
It is known that the substitution of two nitro groups in
TNB under the action of Oꢀ and Sꢀnucleophiles (phenols,
polyfluorinated alcohols, thiols) requires more drastic
temperature conditions than those necessary for the subꢀ
stitution of one nitro group.7—10 This is attributable to the
fact that the substitution of one nitro group in TNB deꢀ
creases the electrophilicity of the product compared to
TNB as such.
i. NꢀMP, 80 °C, K2CO3.
TNB) to give products of replacement of a nitro group in
yields of >70%, whereas the time of complete conversion
of TNB in the reaction with pyrazole under the same
conditions was 30 h, and the yield of compound 13a
was 20%.
Scheme 7
We studied the substitution of a nitro group in comꢀ
pound 4 with various Oꢀ and Sꢀnucleophiles as well as
1,2,4ꢀtriazole (Scheme 8). It appeared that a nitro group
in compound 4 is replaced under conditions identical to
those necessary for the substitution of a nitro group in
TNB (in the case of MeONa, in boiling methanol; in all
other cases, in the presence of K2CO3 in NꢀMP, at 20 °C
for thiols and at 80 °C for all other reagents).
X = H (a), Cl (b), Br (c)
Scheme 8
i. NꢀMP, 80—100 °C, K2CO3.
In our opinion, this is associated with low NHꢀacidity
of unsubstituted pyrazole (pKa(H O) = 14.1). Studies on
2
the kinetics of the formation of stable nucleophile—TNB
adducts (Meisenheimer σꢀcomplexes) demonstrated that
the higher is the basicity of the anion formed by a nucleoꢀ
phile, i.e., the higher is pKa of its conjugated acid (NuH),
the more stable is the Meisenheimer complex3,5 of this
nucleophile with TNB. The stability of a σꢀcomplex is
directly related to the equilibrium concentration of TNB
in solution, and the latter, in turn, determines apparently
the rate of substitution of a nitro group. From this it
follows that the more stable the σꢀcomplex, the lower the
rate of substitution of a nitro group. This accounts for a
Y = OMe (a), SCH2COOMe (b), SPh (c), OCH2CF2CF2H (c),
(e),
(f)
Analysis of the published data on the substitution of
nitro groups in TNB in the reactions with Oꢀ and
Sꢀnucleophiles and comparison of these results with our

592
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Sapozhnikov et al.
Scheme 10
data on the substitution of a nitro group in 2ꢀ(3,5ꢀdiꢀ
nitrophenyl)benzotriazole 4 under the action of the same
nucleophiles led us to the conclusion that the benzoꢀ
triazolꢀ2ꢀyl fragment has a strong activating effect in the
aromatic nucleophilic substitution of a nitro group similar
to that of the nitro group.
The 1,2,4ꢀtriazolꢀ1ꢀyl fragment has an analogous efꢀ
fect. Actually, 1ꢀ(3,5ꢀdinitrophenyl)ꢀ1,2,4ꢀtriazole 12
smoothly reacts with 4ꢀchlorophenol as well as with soꢀ
dium methoxide in methanol under conditions typical of
TNB (Scheme 9), resulting in the substitution of a nitro
group to give products 15 and 16, respectively.
Scheme 9
Scheme 11
An interesting result was obtained in the reaction of
compound 4 with an equivalent amount of benzotriazole.
This reaction would be expected to form a mixture of
compounds 17 and 18 (Scheme 10).
Scheme 12
However, the reaction afforded only one regioisomer,
which was isolated in 92% yield (see Scheme 10). The
structure of compound 18 was established based on the
1H NMR spectrum, which has four signals for the protons
of the 1ꢀsubstituted benzotriazole fragment. In addition,
1
the H NMR NOE experiment revealed the proximity of
the protons of two aromatic rings.
Under standard conditions, compound 18 reacts
with 2,2,3,3ꢀtetrafluoropropanol to form polyfluorinated
ether 19 (Scheme 11).
Under the same conditions, the reaction of compound
18 with benzotriazole gave product 20 containing three
benzotriazole substituents (Scheme 12).
Compound 20 is virtually insoluble in organic solꢀ
vents, trifluoroacetic acid, and sulfuric acid. The 1H NMR
spectrum of this compound in DMSOꢀd6 corroborates
the structure 20. This spectrum has signals with double
intensities belonging to the nonꢀsymmetrically substituted
benzotriazole rings.
Therefore, all three nitro groups in TNB can be sucꢀ
cessively replaced under the action of benzotriazole. It

Substitution of nitro groups in trinitrobenzene
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 3, March, 2004
593
5ꢀChloroꢀ2ꢀ(3,5ꢀdinitrophenyl)benzotriazole (7a). A mixture
of isomers prepared in the reaction of TNB with 5ꢀchloroꢀ
benzotriazole was refluxed in acetone. The undissolved 7a was
filtered off. The yield was 53%, m.p. 211—213 °C. Found (%):
C, 45.52; H, 1.57; Cl, 10.78; N, 22.31. C12H6ClN5O4. Calcuꢀ
should be noted that the transformation of TNB into
1,3,5ꢀtriphenoxybenzene22 in the reaction with an excess
of phenol in the presence of K2CO3 at 200 °C in NꢀMP is
the only known example of the substitution of all nitro
groups in TNB (without a preliminary modification of the
substituents). It should be emphasized that in none of the
cases, did the replacement of the azolyl fragment take
place under the action of nucleophiles, and only the nitro
group was replaced in all cases.
1
lated (%): C, 45.09; H, 1.89; Cl, 11.09; N, 21.91. H NMR, δ:
9.25 (d, 2 H, H(2´), H(6´), 4J = 1.9 Hz); 8.95 (t, 1 H, H(4´),
4J = 1.9 Hz); 8.25 (s, 1 H, H(4)); 8.15 (d, 1 H, H(6)); 7.6 (d,
1 H, H(7)). MS, m/z: 319 [M]+.
5ꢀBromoꢀ2ꢀ(3,5ꢀdinitrophenyl)benzotriazole (7b) was isolated
analogously, the yield was 47%, m.p. 236—238 °C. Found (%):
C, 39.05; H, 1.87; N, 19.95. C12H6BrN5O4. Calculated (%):
Experimental
1
C, 39.58; H, 1.66; N, 19.23. H NMR, δ: 9.30 (d, 2 H, H(2´),
4
4
H(6´), J = 1.9 Hz); 8.90 (t, 1 H, H(4´), J = 2.0 Hz); 8.40 (s,
The 1H NMR spectra were recorded on a Bruker АCꢀ200
instrument in DMSOꢀd6. The 13C NMR spectra were measured
on a Bruker AMꢀ300 instrument. The chemical shifts (δ) are
given relative to Me4Si. The mass spectra were obtained on a
Kratos MSꢀ30 instrument; the ionization energy was 70 eV.
The course of the reactions was monitored by HPLC on
LIQUOCHROM (Model 2010) in the CH3CN—H2O system
(3 : 1); a Silasorbꢀ18 reversedꢀphase column was used. The
melting points of the compounds were determined on a Boetius
hotꢀstage apparatus (the heating rate was 4 K min–1).
The starting compounds, such as TNB,23 4ꢀmethoxyꢀ
benzotriazole,24 4ꢀtrifluoromethylbenzotriazole,25 4ꢀchloroꢀ
pyrazole,26 and 4ꢀbromopyrazole,26 were prepared according to
known procedures. All other starting compounds were commerꢀ
cially available.
Substitution of a nitro group in TNB in the reactions with
NHꢀazoles (general procedure). Potassium carbonate (1.38 g,
10 mmol) and a solution of TNB (2.13 g, 10 mmol) in NꢀMP
(10 mL) were added to a solution of an NHꢀazole (10 mmol) in
NꢀMP (15 mL). The mixture was stirred at 80 °C (HPLC conꢀ
trol) and poured into water. The precipitate that formed was
filtered, washed on a filter several times with 5% HCl to remove
NꢀMP, and dried in air.
1 H, H(4)); 8.10 (d, 1 H, H(6)); 7.7 (d, 1 H, H(7)).
2ꢀ(3,5ꢀDinitrophenyl)ꢀ5ꢀtrifluoromethylbenzotriazole (7c).
A mixture prepared in the reaction of TNB with 5ꢀtrifluoroꢀ
methylbenzotriazole was twice recrystallized from EtOH to afꢀ
ford compound 7c in 65% yield, m.p. 155—157 °C. Found (%):
C, 44.17; H, 1.96; N, 19.41. C13H6F3N5O4. Calculated (%):
C, 44.21; H, 1.71; N, 19.83. 1H NMR, δ: 9.30 (d, 2 H, H(2´),
4
4
H(6´), J = 2.0 Hz); 8.95 (t, 1 H, H(4´), J = 2.0 Hz); 8.65 (s,
1 H, H(4)); 8.35 (d, 1 H, H(6)); 7.8 (d, 1 H, H(7)).
2ꢀ(3,5ꢀDinitrophenyl)ꢀ5ꢀmethoxybenzotriazole (7d). A mixꢀ
ture prepared in the reaction of TNB with 5ꢀmethoxybenzoꢀ
triazole was twice recrystallized from EtOH to afford compound
7d in 65% yield, m.p. 238—240 °C. Found (%): C, 49.38; H, 3.14;
N, 21.88. C13H9N5O5. Calculated (%): C, 49.53; H, 2.88;
N, 22.22. 1H NMR, δ: 9.19 (d, 2 H, H(2´), H(6´), 4J = 2.0 Hz);
8.86 (t, 1 H, H(4´), 4J = 2.0 Hz); 7.97 (d, 1 H, H(7)); 7.34 (s,
1 H, H(4)); 7.22 (d, 1 H, H(6)); 3.91 (s, 3 H, OMe).
1ꢀ(3,5ꢀDinitrophenyl)pyrazole (13a). The reaction time was
30 h at 100 °C. The yield was 20%, m.p. 112—114 °C (from
CHCl3). Found (%): C, 46.41; H, 2.22; N, 24.32. C9H6N4O4.
1
Calculated (%): C, 46.16; H, 2.58; N, 23.93. H NMR, δ: 9.05
(d, 2 H, H(2´), H(6´), 4J = 2.0 Hz); 8.95 (d, 1 H, H(3), 3J =
4
2.7 Hz); 8.71 (t, 1 H, H(4´), J = 1.9 Hz); 7.89 (d, 1 H, H(5),
2ꢀ(3,5ꢀDinitrophenyl)benzotriazole (4). A mixture of isomers
3+4 prepared by the aboveꢀdescribed reaction was recrystallized
from DMF (heating to 120 °C) and isomer 4 was isolated in 40%
yield, m.p. 211—213 °C. Found (%): C, 50.02; H, 2.41; N, 25.25.
C12H7N5O4. Calculated (%): C, 50.53; H, 2.47; N, 24.55.
1H NMR, δ: 9.25 (d, 2 H, H(2´), H(6´), 4J = 2.0 Hz); 8.91 (t,
1 H, H(4´), 4J = 2.0 Hz); 8.05 (dd, 2 H, H(4), H(7), 3J = 6.6 Hz,
3J = 1.7 Hz); 6.72 (t, 1 H, H(4), 3J = 2.8 Hz). 13C NMR, δ:
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´)). MS, m/z:
234 [M]+, 188 [M – NO2], 142 [M – 2 NO2].
4ꢀChloroꢀ1ꢀ(3,5ꢀdinitrophenyl)pyrazole (13b). The reaction
time was 6 h. The yield was 73%, m.p. 124—126 °C (from
CHCl3). Found (%): C, 39.90; H, 1.49; Cl, 13.56; N, 20.66.
C9H5ClN4O4. Calculated (%): C, 40.24; H, 1.88; Cl, 13.20;
N, 20.86. 1H NMR, δ: 9.25 (s, 1 H, H(3)); 9.01 (d, 2 H, H(2´),
H(6´), 4J = 2.0 Hz); 8.70 (t, 1 H, H(4´), 4J = 1.9 Hz); 8.05
(s, 1 H, H(5)).
3
3J = 7.3 Hz); 7.58 (dd, 2 H, H(5), H(6), 3J = 6.6 Hz, J = 7.3).
13C NMR, δ: 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´)). MS, m/z: 285 [M]+.
1ꢀ(3,5ꢀDinitrophenyl)benzotriazole (3). The filtrate obtained
after crystallization of 2ꢀ(3,5ꢀdinitrophenyl)benzotriazole (4)
was concentrated in vacuo. The residue enriched in isomer 3 was
twice recrystallized from dioxane. The yield was 15%, m.p.
184—186 °C. Found (%): C, 50.80; H, 2.93; N, 25.25.
C12H7N5O4. Calculated (%): C, 50.53; H, 2.47; N, 24.55.
1H NMR, δ: 9.05 (d, 2 H, H(2´), H(6´), 4J = 1.9 Hz); 8.95 (t,
1 H, H(4´), 4J = 1.9 Hz); 8.25 (d, 1 H, H(7), 3J = 7.9 Hz); 8.10
(d, 1 H, H(4), 3J = 7.7 Hz); 7.81 (t, 1 H, H(5), 3J = 8.1 Hz);
7.62 (t, 1 H, H(6), 3J = 8.0 Hz). 13C NMR, δ: 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´)). MS, m/z: 285 [M]+, 257 [M – N2]+.
4ꢀBromoꢀ1ꢀ(3,5ꢀdinitrophenyl)pyrazole (13c). The reaction
time was 2 h. The yield was 86%, m.p. 132—134 °C (from
CHCl3). Found (%): C, 34.47; H, 1.36; N, 18.20. C9H5BrN4O4.
1
Calculated (%): C, 34.53; H, 1.61; N, 17.90. H NMR, δ: 9.21
(s, 1 H, H(3)); 8.97 (d, 2 H, H(2´), H(6´), 4J = 2.0 Hz); 8.72 (t,
1 H, H(4´), 4J = 1.9 Hz); 8.02 (s, 1 H, H(5)).
1ꢀ(3,5ꢀDinitrophenyl)ꢀ1,2,3ꢀtriazole (11). The reaction time
was 3 h. The yield was 71%, m.p. 126—128 °C (from EtOH).
Found (%): C, 41.02; H, 1.91; N, 29.34. C8H5N5O4. Calcuꢀ
lated (%): C, 40.86; H, 2.14; N, 29.78. 1H NMR, δ: 8.98 (d, 2 H,
H(2´), H(6´), 4J = 1.9 Hz); 8.82 (t, 1 H, H(4´), 4J = 1.9 Hz);
8.33 (s, 2 H, H(4), H(5)). 13C NMR, δ: 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´)).

594
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Sapozhnikov et al.
4
1ꢀ(3,5ꢀDinitrophenyl)ꢀ1,2,4ꢀtriazole (12). The reaction time
1 H, arom., J = 1.9 Hz); 8.05 (m, 3 H, H(4), H(7), benzotriꢀ
was 6 h. The yield was 75%, m.p. 131—133 °C (from CHCl3).
Found (%): C, 41.12; H, 1.98; N, 30.04. C8H5N5O4. Calcuꢀ
lated (%): C, 40.86; H, 2.14; N, 29.78. 1H NMR, δ: 9.70 (s, 1 H,
H(5)); 9.05 (d, 2 H, H(2´), H(6´), 4J = 2.0 Hz); 8.81 (s, 1 H,
H(4´), 4J = 2.0 Hz); 8.33 (s, 1 H, H(3)). 13C NMR, δ: 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)). MS, m/z: 235 [M]+, 208
[M – HCN].
Substitution of a nitro group in 1,3ꢀdinitroꢀ5ꢀtrifluoroꢀ
methylbenzene in the reaction with benzotriazole. The reaction
was carried out analogously to that with TNB. The reaction
time was 6 h. The yield of a mixture of isomers was 88%. The
isomers were separated by column chromatography on silica gel
(hexane—CH2Cl2).
1ꢀ(3ꢀNitroꢀ5ꢀtrifluoromethylphenyl)benzotriazole (8). The
yield was 44%, m.p. 140—142 °C (from EtOH). Found (%):
C, 50.31; H, 2.56; N, 17.74. C13H7F3N4O2. Calculated (%):
C, 50.66; H, 2.29; N, 18.18. 1H NMR, δ: 8.92, 8.71, and 8.65
(all s, 1 H each, arom.); 8.24 (d, 1 H, H(7), benzotriazole, J =
7.4 Hz); 8.06 (d, 1 H, H(4), benzotriazole); 7.75 (m, 1 H, H(5),
benzotriazole); 7.56 (m, 1 H, H(6) benzotriazole).
azole + arom.); 7.56 (m, 2 H, H(5), H(6), benzotriazole); 6.75
4
3
(tt, 1 H, CH, 3J = 52 Hz, J = 5 Hz); 4.95 (t, 2 H, CH2, J =
12.5 Hz). MS, m/z: 370 [M]+.
2ꢀ[3ꢀ(4ꢀChlorophenoxy)ꢀ5ꢀnitrophenyl]benzotriazole (14e).
The reaction temperature was 80 °C, the reaction time was 6 h.
The product was recrystallized from DMF, the yield was 79%,
m.p. 178—180 °C. Found (%): C, 59.15; H, 2.87; N, 14.86.
C
18H11ClN4O3. Calculated (%): C, 58.95; H, 3.02; N, 15.28.
1H NMR, δ: 8.73 (t, 1 H, arom., 4J = 2 Hz); 8.30 (t, 1 H, arom.,
4J = 1.9 Hz); 8.05 (dd, 2 H, H(4), H(7), benzotriazole); 7.92 (t,
4
1 H, arom., J = 2.1 Hz); 7.75 (m, 4 H, H(5), H(6), benzotriꢀ
azole + H(2), H(6), C6H4O); 7.33 (d, 2 H, H(3), H(5), phenoxy
group). MS, m/z: 366 [M]+.
2ꢀ[3ꢀNitroꢀ5ꢀ(1,2,4ꢀtriazolꢀ1ꢀyl)phenyl]ꢀ1,2,3ꢀbenzotriazole
(14f). The reaction temperature was 80 °C, the reaction time
was 25 h. The product was recrystallized from DMF, the yield
was 87%, m.p. 231—233 °C. Found (%): C, 55.01; H, 2.76;
N, 31.73. C14H9N7O2. Calculated (%): C, 54.72; H, 2.95;
N, 31.91. 1H NMR, δ: 9.75 (s, 1 H, H(5), triazole); 9.20 (t, 1 H,
arom., 4J = 1.9 Hz); 8.98 (t, 1 H, arom., 4J = 2 Hz); 8.85 (t, 1 H,
4
arom., J = 1.9 Hz); 8.4 (s, 1 H, H(3), triazole); 8.09 (m, 2 H,
2ꢀ(3ꢀNitroꢀ5ꢀtrifluoromethylphenyl)benzotriazole (9). The
yield was 23%, m.p. 89—91 °C (from EtOH). Found (%):
C, 50.19; H, 2.11; N, 18.31. C13H7F3N4O2. Calculated (%):
C, 50.66; H, 2.29; N, 18.18. 1H NMR, δ: 9.16, 8.92, and 8.65
(all s, 1 H each, arom.); 8.08 (m, 2 H, H(4), H(7), benzotriazole):
7.59 (m, 2 H, H(5), H(6), benzotriazole).
H(4), H(7), benzotriazole); 7.61 (m, 2 H, H(5), H(6), benzoꢀ
triazole). MS, m/z: 307 [M]+.
1ꢀ[3ꢀ(4ꢀChlorophenoxy)ꢀ5ꢀnitrophenyl]ꢀ1,2,4ꢀtriazole (15).
The reaction temperature was 80 °C, the reaction time was 6 h.
The product was recrystallized from dioxane, the yield was 90%,
m.p. 145—147 °C. Found (%): C, 52.98; H, 3.03; N, 17.32.
C14H9ClN4O3. Calculated (%): C, 53.09; H, 2.86; N, 17.69.
1H NMR, δ: 9.52 (s, 1 H, H(5), triazole); 8.50 (t, 1 H, arom.,
4J = 1.9 Hz); 8.30 (s, 1 H, H(3), triazole); 8.05 (t, 1 H, arom.,
4J = 2 Hz); 7.75 (t, 1 H, arom., 4J = 1.9 Hz); 7.55 and 7.25
(both d, 2 H each, phenoxy group).
1ꢀ(Benzotriazolꢀ1ꢀyl)ꢀ3ꢀ(benzotriazolꢀ2ꢀyl)ꢀ5ꢀnitrobenzene
(18). The reaction temperature was 80 °C, the reaction time
was 4 h. The yield of the crude product was 92%. After crystalliꢀ
zation from dioxane, the yield was 75%. The compound subꢀ
limes without melting. Found (%): C, 59.96; H, 3.43; N, 26.90.
C18H11N7O2. Calculated (%): C, 60.50; H, 3.10; N, 27.44.
1H NMR, δ: 9.15 (t, 1 H, arom., 4J = 1.9 Hz); 9.11 (t, 1 H,
arom., 4J = 2 Hz); 8.80 (t, 1 H, arom., 4J = 1.9 Hz); 8.29 (d,
1 H, H(7)); 8.15 (m, 3 H, H(4), H(4´), H(7´)); 7.82 (t, 1 H,
H(5)); 7.63 (m, 3 H, H(6), H(5´), H(6´)).
1ꢀ(Benzotriazolꢀ1ꢀyl)ꢀ3ꢀ(benzotriazolꢀ2ꢀyl)ꢀ5ꢀ(2,2,3,3ꢀ
tetrafluoropropoxy)benzene (19). The reaction temperature
was 80 °C, the reaction time was 16 h, the yield was 79%,
m.p. 286—288 °C. Found (%): C, 56.77; H, 3.34; N, 18.65.
C21H14F4N6O. Calculated (%): C, 57.02; H, 3.19; N, 19.00.
1H NMR, δ: 8.51 (s, 1 H, arom.); 8.25 (d, 1 H, H(7)); 8.20—8.05
(m, 4 H, arom., H(4), H(4´), H(7´)); 7.85—7.72 (m, 2 H, arom.,
H(5)); 7.62—7.58 (m, 3 H, H(6), H(5´), H(6´)); 6.85 (t, 1 H,
CH, 3J = 52 Hz); 5.02 (t, 2 H, CH2).
Substitution of a nitro group in compounds 4, 12, and 18 in
the reactions with nucleophiles. Potassium carbonate (1.38 g,
10 mmol) and 2ꢀ(3,5ꢀdinitrophenyl)benzotriazole (4) (2.85 g,
10 mmol) were added to a solution of a nucleophile (10 mmol)
in NꢀMP (25 mL). The reaction mixture was kept at the correꢀ
sponding temperature (HPLC control) and poured into water.
The precipitate that formed was filtered, washed several times
on a filter with 5% HCl to remove NꢀMP, and dried in air.
Methyl Sꢀ[3ꢀ(1,2,3ꢀbenzotriazolꢀ2ꢀyl)ꢀ5ꢀnitrophenyl]merꢀ
captoacetate (14b). The reaction temperature was 20 °C, the
reaction time was 2 h. The product was recrystallized from dioxꢀ
ane, the yield was 90%, m.p. 143—145 °C. Found (%): C, 51.96;
H, 3.62; N, 15.77; S, 9.40. C15H12N4O4S. Calculated (%):
1
C, 52.32; H, 3.51; N, 16.27; S, 9.31. H NMR, δ: 8.71 (t, 1 H,
arom., 4J = 1.9 Hz); 8.57 (t, 1 H, arom., 4J = 2 Hz); 8.25 (t, 1 H,
4
arom., J = 1.9 Hz); 8.03 (m, 2 H, H(4), H(7), benzotriazole);
7.54 (m, 2 H, H(5), H(6), benzotriazole); 4.21 (s, 2 H, CH2);
3.70 (s, 3 H, OMe).
2ꢀ[3ꢀNitroꢀ5ꢀ(phenylthio)phenyl]benzotriazole (14c). The reꢀ
action temperature was 20 °C, the reaction time was 1 h. The
product was recrystallized from DMF, the yield was 93%, m.p.
156—158 °C. Found (%): C, 61.82; H, 3.17; N, 15.87; S, 9.42.
C18H12N4O2S. Calculated (%): C, 62.06; H, 3.47; N, 16.08;
S, 9.20. 1H NMR, δ: 8.72 (t, 1 H, arom., 4J = 2 Hz); 8.35 (t,
4
1 H, arom., J = 1.9 Hz); 8.03 (m, 3 H, H(4), H(7), benzotriꢀ
1,3ꢀBis(benzotriazolꢀ1ꢀyl)ꢀ5ꢀ(benzotriazolꢀ2ꢀyl)benzene (20).
The reaction temperature was 80 °C, the reaction time was 30 h.
After refluxing in DMF (50 mL), the analytically pure comꢀ
pound was isolated in 69% yield. The compound sublimes withꢀ
out melting. Found (%): C, 66.61; H, 3.87; N, 28.69. C24H15N9.
azole + arom.); 7.65 (m, 2 H, H(5), H(6), benzotriazole); 7.55
(m, 5 H, thiophenoxy group).
2ꢀ[3ꢀNitroꢀ5ꢀ(2,2,3,3ꢀtetrafluoropropoxy)phenyl]benzotriꢀ
azole (14d). The reaction temperature was 80 °C, the reaction
time was 2 h. The product was recrystallized from dioxane, the
yield was 84%, m.p. 140—142 °C. Found (%): C, 49.01; H, 2.37;
N, 14.73. C15H10F4N4O3. Calculated (%): C, 48.66; H, 2.72;
1
Calculated (%): C, 67.12; H, 3.52; N, 29.35. H NMR, δ: 9.15
(s, 2 H, arom.); 8.82 (s, 1 H, arom.); 8.27 (d, 2 H, 2 H(7)); 8.15
(m, 4 H, 2 H(4), H(4´), H(7´)); 7.77 (t, 2 H, 2 H(5)); 7.55 (m,
4 H, 2 H(6), H(5´), H(6´)).
1
4
N, 15.13. H NMR, δ: 8.68 (t, 1 H, arom., J = 2 Hz); 8.38 (t,

Substitution of nitro groups in trinitrobenzene
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 3, March, 2004
595
2ꢀ(3ꢀMethoxyꢀ5ꢀnitrophenyl)benzotriazole (14a). A mixture
of 2ꢀ(3,5ꢀdinitrophenyl)benzotriazole 4 (2.85 g, 10 mmol) and
sodium methoxide (0.54 g, 10 mmol) in methanol (10 mL) was
refluxed for 30 h and poured into water. The precipitate that
formed was filtered off and recrystallized from DMF. The yield
was 2.1 g (78%), m.p. 202—204 °C. Found (%): C, 58.06;
H, 3.91; N, 20.49. C13H10N4O3. Calculated (%): C, 57.78;
H, 3.73; N, 20.73. 1H NMR, δ: 8.85 and 8.18 (both t, 1 H each,
8. S. A. Shevelev, M. D. Dutov, M. A. Korolev, O. Yu.
Sapozhnikov, and A. L. Rusanov, Mendeleev Commun.,
1998, 69.
9. S. A. Shevelev, M. D. Dutov, and O. V. Serushkina, Izv.
Akad. Nauk, Ser. Khim., 1995, 2528 [Russ. Chem. Bull., 1995,
44, 2424 (Engl. Transl.)].
10. S. A. Shevelev, M. D. Dutov, I. A. Vatsadze, M. A. Korolev,
and A. L. Rusanov, Mendeleev Commun., 1996, 155.
11. S. A. Shevelev, I. A. Vatsadze, and M. D. Dutov, Mendeleev
Commun., 2002, 196.
12. F. Terrier, F. Debleds, J. Halle, and M. Simonnin, Tetraꢀ
hedron Lett., 1982, 4079.
4
arom., J = 1.9 Hz); 8.05 (m, 2 H, H(4), H(7), benzotriazole);
7.83 (t, 1 H, arom., 4J = 2 Hz); 7.55 (m, 2 H, H(5), H(6),
benzotriazole); 4.00 (s, 3 H, OMe). MS, m/z: 270 [M]+,
224 [M – NO2].
1ꢀ(3ꢀMethoxyꢀ5ꢀnitrophenyl)ꢀ1,2,4ꢀtriazole (16). A mixture
of 1ꢀ(3,5ꢀdinitrophenyl)ꢀ1,2,4ꢀtriazole (12) (2.35 g, 10 mmol)
and sodium methoxide (0.54 g, 10 mmol) in methanol (10 mL)
was refluxed for 4 h and then poured into water. The precipitate
that formed was filtered off and recrystallized from EtOH. The
yield was 1.45 g (65%), m.p. 129—131 °C. Found (%): C, 48.67;
H, 3.79; N, 25.03. C9H8N4O3. Calculated (%): C, 49.09; H, 3.66;
N, 25.45. 1H NMR, δ: 9.53 (s, 1 H, H(5), triazole); 8.31 (s, 1 H,
H(3), triazole); 8.28 (t, 1 H, arom., 4J = 1.9 Hz); 7.89 (t, 1 H,
arom., 4J = 2 Hz); 7.71 (t, 1 H, arom., 4J = 1.9 Hz); 3.94 (s,
3 H, OMe).
13. M. Simonnin, F. Terrier, M. Pouet, and J. Halle, Can.
J. Chem., 1985, 866.
14. F. Terrier, F. Debleds, J. Halle, M. Simonnin, and M. Pouet,
Can. J. Chem., 1982, 1988.
15. T. Kitamura, N. Tashi, K. Tsuda, and Y. Fujiwara, Tetraꢀ
hedron Lett., 1998, 3787.
16. J. F. K. Wilshire, Aust. J. Chem., 1966, 1935.
17. M. Kamel, M. I. Ali, and M. M. Kamel, Tetrahedron,
1967, 2863.
18. I. P. Beletskaya, D. V. Davydov, and M. MorenoꢀManas,
Tetrahedron Lett., 1998, 5621.
19. SukꢀKu Kang, SangꢀHo Lee, and D. Lee, Synlett, 2000, 1022.
20. P. A. Grieco and J. P. Mason, J. Chem. Eng. Data, 1967, 623.
21. R. F. Hudson, Chemical Reactivity and Reaction Paths,
Ed. G. Klopman, WileyꢀInterscience Publ., New York,
1974, Ch. 5.
22. S. A. Shevelev, M. D. Dutov, I. V. Vatsadze, O. V.
Serushkina, M. A. Korolev, and A. L. Rusanov, Izv. Akad.
Nauk, Ser. Khim., 1995, 393 [Russ. Chem. Bull., 1995, 44,
384 (Engl. Transl.)].
23. Organic Syntheses, Coll. Vol. I, Ed. H. Gilman, J. Wiley and
Sons, Inc., New York, 1946, p. 541.
24. I. Kh. Fel´dman and V. S. Usovskaya, Zh. Obshch. Khim.,
1948, 18, 1699 [J. Gen. Chem. USSR, 1948, 18 (Engl.
Transl.)].
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Received December 29, 2003;
in revised form February 11, 2004