Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines

Article abstract of DOI:10.1016/j.jfluchem.2005.06.001

The coupling of trifluoromethylated 1,3-diketones with (het)aryldiazonium chlorides results mainly in the formation of 1,2,3-triketones 2-(het)arylhydrazones while using hetarylamine with a NH-group at the α-position of the heterocycle as the diazonium co

Full text of DOI:10.1016/j.jfluchem.2005.06.001

Journal of Fluorine Chemistry 126 (2005) 1230–1238
www.elsevier.com/locate/fluor
Synthesis and the reactions of trifluoromethylated 1,2,3-triketones
2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines
a
a
a
b
O.G. Khudina a, , E.V. Shchegol’kov , Ya.V. Burgart , M.I. Kodess , O.N. Kazheva ,
*
A.N. Chekhlov b, G.V. Shilov b, O.A. Dyachenko b, V.I. Saloutin a, O.N. Chupakhin a
a Institute of Organic Synthesis, Urals Division of the Russian Academy of Sciences, 22/20,
S. Kovalevskoy/Akademicheskaya Street, 620219 Ekaterinburg, Russia
b Institute of Problems of Chemical Physics of the Russian Academy of Sciences, 5, Academician Semenov Avenue, 142432 Chernogolovka, Russia
Received 6 April 2005; received in revised form 27 May 2005; accepted 4 June 2005
Available online 27 June 2005
Abstract
The coupling of trifluoromethylated 1,3-diketones with (het)aryldiazonium chlorides results mainly in the formation of 1,2,3-triketones 2-
(het)arylhydrazones while using hetarylamine with a NH-group at the a-position of the heterocycle as the diazonium component gives 4,7-
dihydroazolo[5,1-c]triazines due to cyclization at the trifluoroacetyl fragment. Trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones
and 7-hydroxy-4,7-dihydroazolo[5,1-c]triazines react regio-selectively with methyl hydrazine and phenyl hydrazine to form 3-CF3-pyrazoles.
The long-range coupling constants (JF-H) of 1-methylpyrazoles and the chemical shifts of trifluoromethyl groups in the 19F NMR spectra can
be used for the determination of regio-isomeric structures of mono(trifluoromethyl)-substituted pyrazoles. 2-(Het)arylhydrazones and 4,7-
dihydroazolo[5,1-c]triazines with two trifluoromethyl substituents afford the mixtures of cis- and trans-azopyrazoles in the reactions with
hydrazines.
# 2005 Elsevier B.V. All rights reserved.
Keywords: Cyclizations; Regio-selectivity; Heterocycles; Isomers
1. Introduction
2. Results and discussion
The design of selective inhibitors of cyclooxygenase-2
possessing anti-inflammatory activity and small or no
gastric side effects is very important [1–3]. It is known
that 4-[5-(4-methylphenyl)-3-trifluoromethyl-1H-pyrazol-
1-yl]benzenesulfonamide (celecoxib) selectively inhibits
the cyclooxygenase-2 enzyme. In this paper we focused our
attention on the preparation of structural analogs of
celecoxib. Herein we report the regioselective synthesis
of new 3-trifluoromethylpyrazoles by the reaction of
trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones
and 4,7-dihydroazolo[5,1-c]triazines with substituted
hydrazines.
2.1. Synthesis of trifluoromethyl-substituted 1,2,3-
triketones 2-(het)arylhydrazones and 4,7-
dihydroazolo[5,1-c][1,2,4]triazines. Ring-chain
isomerism of 2-hetarylhydrazones
We have studied the coupling of mono- and bis(trifluoro-
methyl)-containing 1,3-diketones 1 with aryl- and hetar-
yldiazonium chlorides aimed at the preparation of novel
trifluoromethylated building blocks.
It has been found that trifluoromethyl-containing 1,3-
diketones 1a,b are coupled with aryl- and (antipyrin-4-
yl)diazonium chlorides in the presence of sodium acetate to
afford products 2a–d in 37–57% yields (Scheme 1). The IR
and NMR spectra of compounds 2a–d indicate, that these
products exist in CHCl3 solution and in the crystals as a
hydrazono-diketo tautomer, although both keto-enol and azo-
hydrazone tautomerisms are possible for these compounds.
* Corresponding author. Tel.: +7 343 3493491; fax: +7 343 3745954.
E-mail address: kog@ios.uran.ru (O.G. Khudina).
0022-1139/$ – see front matter # 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2005.06.001

O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
1231
Scheme 1.
It has been shown that 1,1,1,5,5,5-hexafluoro-2,4-
Besides X-ray diffraction and 13C NMR spectroscopy 19
F
NMR spectroscopy can be used as a simple and reliable
method for the determination of the cyclic or acyclic structure
of the coupling products with the trifluoromethyl substituent.
The trifluoromethyl group in azolo[5,1-c]azines 3 is disposed
at the sp3-hybridized carbon atom, so the fluorine nuclei
of these compounds have 19F NMR chemical shifts at
approximately ꢀ78–(ꢀ77) ppm, while in mono(trifluoro-
methyl)-substituted 2,3,4-pentanetrione 3-(het)arylhydra-
zones 2b,d the chemical shifts of the trifluoromethyl group
connected with the carbonyl carbon are observed at
approximately ꢀ73–(ꢀ71) ppm.
pentanedione 1a undergoes partial Japp–Klingemann
cleavage under the reaction conditions [4]. Formazan 4 as
a side product is likely to be obtained as a result of the
coupling of Japp–Klingemann cleavage product B with a
second aryldiazonium salt molecule (Scheme 2).
In contrast to the reactions described above, trifluoro-
methyl-containing 1,2,3-triketones 2-hetarylhydrazones A
were not isolated from the reactions of 1,3-diketones 1a–c
with (4-ethoxycarbonylpyrazol-3-yl)- and (1,2,4-triazol-3-
yl)diazonium chlorides. Under the reaction conditions they
cyclized readily to 4,7-dihydroazolo[5,1-c][1,2,4]triazines
3a–d in 59–68% yields. The cyclization occurs through
nucleophilic addition of the amino group of the azole
fragment to the trifluoromethyl-substituted carbonyl group
(Scheme 1). The quartet signals of carbon atoms connected
with the trifluoromethyl substituent at 80.1–82.2 ppm (3JC-
F = 34.6–34.9 Hz) (see Section 4) in the spectra 13C NMR in
DMSO-d6 solution testify that products 3a,c,d have 4,7-
dihydroazolo[5,1-c][1,2,4]triazine structures.
Non-fluorinated 2,4-pentanedione coupled readily with
(1,2,4-triazol-3-yl)diazonium nitrate at room temperature to
give 2,4-pentanedione 1,2,4-triazol-3-ylhydrazone with high
yield, which only on heating was transformed into
[1,2,4]triazolo[5,1-c][1,2,4]triazine hemihydrate [5]. The
latter was also formed directly by heating a mixture of
1,2,4-triazole-3-yldiazonium nitrate and 2,4-pentanedione in
aqueous ethanolic sodium acetate [5]. The product obtained
by us according to the second method melts with decom-
position at 200 8C and its microanalysis data correspond
to 6-acetyl-7-hydroxy-7-methyl-4,7-dihydro[1,2,4]triazolo
[5,1-c][1,2,4]triazine 3e.
The structure of ethyl-6-benzoyl-7-hydroxy-7-trifluoro-
methyl-4,7-dihydropyrazolo[5,1-c][1,2,4]triazine-3-carbox-
ylate 3c was confirmed also by the single-crystal X-ray
diffraction analysis (Fig. 1). This cyclic derivative of the
hetarylhydrazone is stabilized due to the participation of the
hydroxyl group in an intramolecular hydrogen bond with the
carbonyl group of the benzoyl fragment.
It has been found that the ring-chain isomerism is typical
for trifluoromethyl-containing 4,7-dihydroazolo[5,1-c]tri-
azines 3a–d unlike the non-fluorinated analogue 3e.
Scheme 2.

1232
O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
Fig. 1. X-Ray structure of ethyl-6-benzoyl-7-hydroxy-7-trifluoromethyl-4,7-dihydropyrazolo[5,1-c][1,2,4]triazine-3-carboxylate 3c.
The ring-chain isomerism of pyrazolo[5,1-c]triazine 3c was
observed by 19F NMR spectroscopy. So, together with CF3-
group singlet at ꢀ78 ppm, a second singlet at ꢀ70.9 ppm
appearedinMeODat25 8C.Thelatterchemicalshiftistypical
for 1-phenyl-4,4,4-trifluoro-1,2,3-butanetrione 2-(4-ethoxy-
carbonylpyrazol-3-yl)hydrazone A (compare with the che-
mical shifts of mono(trifluoromethyl)-substituted 2,3,4-
pentanetrione 3-(het)arylhydrazones 2b,d). The ratio of
hydrazone A and cyclic derivative 3c at 25 8C in MeOD
was 0.8:99.2.
have found that hydrazones 2a,b,d react with hydrazines at
the 1,3-dicarbonyl fragment to afford pyrazoles 5a–c, 6a in
65–78% yields (Scheme 3).
Pyrazoles 5d,e, 6b obtained in 58–75% yields were the
final products also in the reactions of 4,7-dihydrotriazolo[5,1-
c]triazines 3a,d with methyl hydrazine and phenyl hydrazine.
It is likely that the 4,7-dihydroazolo[5,1-c]triazines 3 undergo
ring opening in refluxing ethanol to give 1,2,3-triketones
2-hetarylhydrazones A, which further react with these
hydrazines on 1,3-dicarbonyl fragment (Scheme 3).
The cyclocondensation of non-symmetrical mono(tri-
fluoromethyl)-containing 1,2,3-triketones 2-(het)arylhydra-
zones with substituted hydrazines can afford 3-CF3 and 5-
CF3 regio-isomeric pyrazoles or their mixture. In addition,
4-(het)arylazopyrazoles can exist in the cis-azo and trans-
azo forms or as their mixture.
2.2. Reactions of 1,2,3-triketones 2-(het)arylhydrazones
and 4,7-dihydroazolo[5,1-c]triazines with methyl
hydrazine and phenyl hydrazine
Then trifluoromethylated 1,2,3-triketones 2-(het)arylhy-
drazones 2 and their cyclic derivatives 3 were used as the
starting building blocks for synthesis of trifluoromethyl-
containing pyrazoles of potential inflammatory activity. In
this connection the interaction of compounds 2 and 3 with
methyl hydrazine and phenyl hydrazine was studied. We
The structure of 1,5-dimethyl-4-phenylazo-3-trifluoro-
methylpyrazole 5a was determined by the X-ray diffraction
analysis. Pyrazole 5a exists in the crystals as two possible
molecular conformations—I and II in a ratio of 81:19
(Fig. 2).
Scheme 3.

O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
1233
Fig. 2. X-Ray structure of 1,5-dimethyl-4-phenylazo-3-trifluoromethylpyrazole 5a. Possible molecule conformations in crystal: (I) probability of the
conformation is 0.81; (II) probability of the conformation is 0.19.
The 19F NMR spectrum of the product 5a in CDCl3 has
the quartet signal of the trifluoromethyl substituent at
ꢀ62.6 ppm with a spin-spin coupling constant 0.5 Hz (see
Section 4). A similar long-range coupling constant (6JH-
F = 0.6 Hz) was observed in 3-trifluoromethyl-4,5,6,7-tetra-
hydro-1-methyl-1H-indazole in CDCl3 [6]. Unlike these
compounds, 4-methyl-5-trifluoromethyl-3,4-diazatetracy-
clo[7.3.1.17,11.02,6]tetradeca-2,5-diene with the vicinal dis-
posed methyl and trifluoromethyl substitutes has a long-
5a–e, 6a,b both in CCl4 and Nujol mulls contain only the
absorption bands at 1422–1447 cmꢀ1 corresponding to the
trans-azo group (see Section 4) [10]. The content of the cis-
azo pyrazole increases to 25% in CDCl3 solution in the case
of 4-(4-ethoxycarbonylpyrazol-3-ylazo)-substituted pyra-
zole 5d. In its IR spectrum in CCl4 together with the
trans-azo group absorption band at 1426 cmꢀ1 appears the
high-frequency absorption band of the cis-azo group at
1507 cmꢀ1 (see Section 4) [10].
1
range spin-spin coupling constant 1.2 Hz in the H NMR
The values of spin-spin coupling constants in the 1H, 19
F
spectrum in CDCl3 [7]. Thus, the value of a coupling
constant between the protons of the NMe fragment and the
fluorine nuclei of the CF3 group allows us to draw a
conclusion about the regio-isomer structure.
NMR spectra of pyrazoles 5b,d made it possible to attribute
the 19F NMR chemical shifts at ꢀ63.8–(ꢀ62.7) ppm (6JF-
H = 0.0–0.5 Hz) to 3-CF3 groups, and the quartet signals at
ꢀ60.8–(ꢀ58.8) ppm (5JF-H = 0.9–1.3 Hz) (see Section 4) to
5-CF3 substituents of compounds 5b,d (Scheme 4). The
chemical shifts of the fluorine nuclei of 4-arylazo-3,5-
bis(trifluoromethyl)-1-phenylpyrazole 6a were similar. So,
the 19F NMR spectra of cis-, trans-azo isomers revealed the
singlet signals at ꢀ63.1–(ꢀ62.8) ppm belonging to 3-CF3
substituents and the signals at ꢀ58.4–(ꢀ56.5) ppm
corresponding to 5-CF3 groups (see Section 4).
Singh et al [8] reported that the regio-isomeric structures
of pyrazoles obtained from mono-trifluoromethyl-contain-
ing 1,3-diketones and hydrazines can be judged from the
position of the signal of the trifluoromethyl group in the 19
F
NMR spectra. So, the signals of the trifluoromethyl fragment
of 4-unsubstituted [8] and 4-fluoro-substituted [9] pyrazoles
were observed at approximately ꢀ62 ppm for the 3-CF3-
pyrazoles and at approximately ꢀ58 ppm for the 5-CF3-
isomers, respectively. The NMR spectroscopy data of
pyrazole 5a, which structure was confirmed by the X-ray
diffraction analysis, correlate with the data cited in the works
[8,9].
The chemical shifts at ꢀ63.1–(ꢀ61.4) ppm in the 19F
NMR spectra of mono(trifluoromethyl)-substituted pyra-
zoles 5c,e, 6b and the values of long-range coupling
constants 0–0.5 Hz in the compounds 5c,e are evidence for
3-CF3-pyrazole structure of these heterocycles (see Section
4).
Thus, we have shown that non-symmetrical mono(tri-
fluoromethyl)-containing 1,2,3-triketones 2-(het)arylhydra-
zones 2 and 4,7-dihydroazolo[5,1-c]triazines 3 interact with
the substituted hydrazines to form only 3-CF3-pyrazoles.
It confirms that 4,7-dihydroazolo[5,1-c]triazines at first
undergo the triazine ring opening under the reaction
conditions and then the chain form react with hydrazines.
In contrast to the reactions of fluorinated 4,7-dihydro-
azolo[5,1-c]triazines 3a,d described above, non-fluorinated
6-acetyl-7-hydroxy-4,7-dihydro[1,2,4]triazolo[5,1-
c][1,2,4]triazine 3e does not react with methyl hydrazine and
phenyl hydrazine in refluxing ethanol. Using refluxing
toluene was also unsuccessful. Evidently, the acetyl group in
the non-fluorinated analogue is less reactive and does not
react with these dinucleophiles even with retaining the
heterocyclic nucleus. Besides, the compound 3e is more
NMR spectral characteristics of bis(trifluromethyl)-
containing pyrazoles 5b, 6a testify that these compounds
exist as the mixtures of trans-azo and cis-azo pyrazoles in a
ratio of ꢁ95:5 in CDCl3 solutions unlike 3-CF3-pyrazoles
5a,c,e, 6b. However, IR spectra of all synthesized pyrazoles

1234
O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
Scheme 4.
The 1H and 19F NMR spectra of pyrazoline 7 display also
the long range coupling constants between the fluorine
nuclei of two CF3 groups and the protons of NMe and CH2
fragments (Scheme 6). In this compound 3-CF3 substituent
resonates in the 19F NMR spectrum at ꢀ67.6 ppm, but the 5-
CF3 group at quaternary carbon atom has the more upfield
resonance at ꢀ80.6 ppm (see Section 4).
Scheme 5.
stable and not subjected to ring-chain isomerism unlike the
fluorinated heterocycles 3a–d, since the products of the
interaction of hydrazines with the chain form of compound
3e have not been obtained. Obviously, the CF3 group at
position 7 of 4,7-dihydroazolo[5,1-c]triazines 3a–d with-
drawing electronic density on itself destabilizes the ring
form and promotes the triazine ring opening.
3. Conclusion
We have shown that coupling of trifluoromethylated 1,3-
diketones 1a–c with (het)aryldiazonium chlorides results
mainly in the formation of 1,2,3-triketones 2-(het)arylhy-
drazones 2a–d while using hetarylamine with NH-group at
the a-position of heterocycle as the diazonium component
gives 4,7-dihydroazolo[5,1-c]triazines 3a–d due to cycliza-
tion at the trifluoroacetyl fragment.
2.3. Reactions of 1,1,1,5,5,5-hexafluoropentan-2,4-
dione with methylhydrazine
We have studied the effect of trifluoromethyl group
combined with arylhylhydrazone substituent on the regio-
selectivity of the reactions of non-symmetrical 1,3-
diketones with the substituted hydrazines. It has been found
that in contrast to 2-unsubstituted monofluoroalkyl contain-
ing 1,3-diketones [12] the interaction of mono(trifluoro-
methyl)-substituted 2-(het)arylhydrazones with hydrazines
is regio-selective process as the primary amino group of the
hydrazine attacks the more electrophilic trifluoroacetyl
group to result in 3-CF3-pyrazoles exclusively.
To obtain additional information about the NMR spectral
characteristics (chemical shift, spin-spin coupling constant)
of the CF3 group in pyrazoles we have studied the reaction of
1,1,1,5,5,5-hexafluoropentan-2,4-dione 1a with methylhy-
drazine under similar conditions. Unlike 1,2,3-triketones 2-
(het)arylhydrazones 2a,b,d and their cyclic derivatives 3a,d
it forms 3,5-bis(trifluoromethyl)-5-hydroxy-1-methylpyra-
zoline 7 in 76% yield (Scheme 5). The treatment of dione 1a
with more hindered arylhydrazines gave also the partially
hydrated pyrazoles [11]. The differences in the reactivity of
1,1,1,5,5,5-hexafluoropentane-2,4-dione and its 2-(het)ar-
ylhydrazones towards methylhydrazine may be explained by
the presence of the bulky (het)arylhydrazone fragment
producing the steric hindrances in the pyrazoline molecule.
The ability of 6-acyl-7-hydroxy-7-trifluoromethyl-4,7-
dihydroazolo[5,1-c]triazines 3a,d to interact with dinucleo-
philic reagents on 1,3-dicarbonyl fragment similar to 1,2,3-
triketones 2-(het)arylhydrazones 2a,b,d due to the ring-
chain isomerism distinguishes them from non-fluorinated
analogue 3e which does not react with methyl hydrazine and
phenyl hydrazine even under the more severe conditions.
High reactivity of compounds 3a,d is due to the presence of
the electron-withdrawing CF3 group at position 7 activating
the neighboring quaternary carbon.
4. Experimental
Melting points were measured in open capillaries and are
uncorrected. The infrared spectra were recorded on Perkin-
Elmer Spectrum One FT-IR spectrometer at 4000–400 cmꢀ1
Scheme 6.

O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
1235
in nujol mulls. The 1H and 13C NMR spectra were measured
on a Bruker DRX-400 spectrometer (1H, 400 MHz, 13C,
100.6 MHz) relative to SiMe4. The 19F NMR spectra were
became turbid. The resulting precipitate was filtered off,
recrystallized from ethanol.
The product 3e was obtained by the literature method [5].
obtained on
a
Bruker DRX-400 spectrometer (19F,
376 MHz) using C6F6 as an internal standard. The chemical
shifts were converted from C6F6 to CCl3F. UV spectra were
recorded on a Shimadzu UV-2401 PC spectrophotometer.
The microanalyses were carried out on a Perkin-Elmer PE
2400 series II elemental analyzer. The column chromato-
graphy was performed on silica gel L 100/250.
4.1.1. 1,1,1,5,5,5-Hexafluoropentane-2,3,4-trione 3-(p-
tolyl)hydrazone (2a)
Yield after column chromatography (with hexane–acetone
(1:1) as an eluent), 37%; mp, 90–91 8C. 1H NMR (CDCl3) d:
2.42 (3H, s, Me), 7.31 (2H, d, H-m, J = 8.6 Hz), 7.44 (2H, d,
H-o, J = 8.6 Hz), 14.58 (1H, br.s, NH) ppm. 13C NMR
(CDCl3) d: 21.3 (Me), 115.6 (q, C-5, 1JC-F = 287.5 Hz), 117.0
(q, C-1, 1JC-F = 292 Hz), 118.0 (C-o), 124.1 (C-3), 130.9 (C-
m), 137.7 (C-i), 140.0 (C-p), 174.9 (q, C-4, 2JC-F = 33.9 Hz),
The X-ray studies were performed on a KM-4 KUMA
DIFFRACTION (for 3c) and Enraf-Nonius CAD-4 (for 5a)
diffractometers with v/2u scanning and graphite monochro-
matic Mo Ka radiation. The crystal structures were solved
by direct methods followed by Fourier synthesis with
SHELXS-97 and refined by full-matrix least-squares
methods for all non-hydrogen atoms with SHELXL-97
software packages [13]. The coordinates of H-atoms were
found experimentally and refined in an isotropic approx-
imation.
2
176.7 (qq, C-2, JC-F = 39.7, J = 1.2 Hz) ppm. 19F NMR
(CDCl3) d: ꢀ75.6 (3F, s, C-5-F3), ꢀ72.1 (3F, d, C-1-F3, JF-
NH = 0.9 Hz) ppm. IR: 3470, 1595 (NH), 1710, 1655 (C=O),
1605, 1520 (C=N, C=C), 1200-1170 (C–F) cmꢀ1. Analysis:
Calc. for C12H8F6N2O2: C, 44.2; H, 2.5; F, 34.9; N, 8.6%.
Found: C, 44.6; H, 2.4; F, 35.1; N, 8.7%.
Main crystallographic data for 3c: C16H13F3N4O4,
M = 382.30, space group P21/c, monoclinic, a = 10.137(2),
4.1.2. 1,1,1-Trifluoropentane-2,3,4-trione 3-(2,3-
dimethyl-5-oxo-1-phenyl-1,2-dihydropyrazol-4-
yl)hydrazone (2b)
˚
b = 7.501(2), c = 22.147(4) A, a = 908, b = 94.73(3)8,
3
1
˚
g = 908, V = 1678.3(6) A , T = 293(2) K, Z = 4, Dcalc
=
Yield, 43%; mp, 173–175 8C. H NMR (CDCl3) d: 2.56
1.51 g/cm3, m(Mo Ka) = 0.132 mmꢀ1, 4619 reflections
measured, 3277 unique reflections which were used in all
calculations, 1730 reflections with [F0 > 4s(F0)]. The final R
is 0.040. CCDC 259365 contains the supplementary crystal-
lographic data for this compound.1
(3H, s, Me), 2.59 (3H, s, Me), 3.20 (3H, s, NMe), 7.37 (3H,
m, H-o, H-p), 7.50 (2H, m, H-m), 15.34 (1H, br.s, NH) ppm.
13C NMR (CDCl3) d: 11.3 (q, Me, JC-F = 1.5 Hz), 31.0 (C-5),
35.6 (NMe), 113.3 (C-40), 117.5 (q, C-1, 1JC-F = 292.4 Hz),
124.7 (C-o), 127.8 (C-p), 128.6 (C-3), 129.5 (C-m), 133.8
2
Main crystallographic data for 5a: C12H11F3N4,
¯
M = 268.25, space group P1, triclinic, a = 7.263(1),
(C-i), 144.2 (C-30), 158.5 (C-50), 176.5 (q, C-2, JC-
F = 32.2 Hz), 196.9 (q, C-4, J = 1 Hz) ppm. 19F NMR
(CDCl3) d: ꢀ71.8 (d, CF3, J = 0.7 Hz) ppm. IR (CHCl3,
nujol mulls): 3450, 1595 (NH), 1695, 1685, 1670 (C=O),
˚
b = 8.662(2), c = 11.183(2) A, a = 83.13(2)8, b = 71.19(2)8,
3
˚
g = 85.26(2)8, V = 660.5(2) A , T = 293(2) K, Z = 2,
D
calc = 1.35 g/cm3, m(Mo Ka) = 0.114 mmꢀ1, 2274 reflec-
1610, 1525, 1490 (C=N, C=C), 1120–1230 (C–F) cmꢀ1
.
tions measured and unique which were used in all
calculations, 1818 reflections with [F0 > 4s(F0)]. The final
R is 0.050. CCDC 259364 contains the supplementary
crystallographic data for this compound.1N(3) and N(4)
atoms of the azo-group are disordered at two positions with
populations 0.81 and 0.19. In the crystal the conformation
with N(4) atom in cis-position towards CF3 group is preferred
(Fig. 2).
Analysis: Calc. for C16H15F3N4O3: C, 52.2; H, 4.1; F, 15.5;
N, 15.2%. Found: C, 52.2; H, 3.9; F, 15.5; N, 15.4%.
4.1.3. 1,1,1,5,5,5-Hexafluoropentane-2,3,4-trione 3-(p-
methoxylphenyl)hydrazone (2c)
Yield after column chromatography (with dichloro-
1
methane as an eluent), 57%; mp, 111–112 8C. H NMR
(CDCl3) d: 3.88 (3H, s, OMe), 7.02 (2H, d, H-m, J = 8.9 Hz),
7.51 (2H, d, H-o, J = 8.9 Hz), 14.75 (1H, br.s, NH) ppm. 13
C
NMR ((CD3)2CO) d: 56.2 (OMe), 116.2 (C-m), 119.9 (q, C-
1,5, 1JC-F = 282.3 Hz), 121.0 (C-o), 124.5 (C-3), 135.1 (C-i),
4.1. Coupling of trifluoromethylsubstituted 1,3-
diketones with (het)aryldiazonium salts
2
161.4 (C-p), 175.6 (q, C-2,4, JC-F = 34.7 Hz) ppm. 19F
NMR (CDCl3) d: ꢀ75.7 (3F, s, C-5-F3), ꢀ72.2 (3F, d, C-1-
F3, JF-NH = 0.7 Hz) ppm. IR: 3100, 1590 (NH), 1705, 1680
(C=O), 1620, 1580, 1505 (C=N, C=C), 1200-1170 (C–F)
cmꢀ1. Analysis: Calc. for C12H8F6N2O3: C, 42.1; H, 2.4; F,
33.3; N, 8.2%. Found: C, 42.4; H, 2.5; F, 33.5; N, 8.1%.
A solution of a diazonium salt prepared from (het)ar-
ylamine (10 mmol), concentrated HCl (20 ml) and NaNO2
(0.70 g, 10 mmol) in water (20 ml) was added by portions to
a solution of the 1,3-diketone 1a–c (10 mmol) in ethanol
(30 ml) at 10–12 8C under stirring. A saturated aqueous
solution of NaOAc was then added slowly until the solution
4.1.4. 1,1,1-Trifluoropentane-2,3,4-trione 3-
phenylhydrazone (2d)
1
These data can be obtained free of charge via http://www.ccdc.cam.a-
Yield after column chromatography (with chloroform as
an eluent), 41%; mp, 110–111 8C. 1H NMR (CDCl3) d: 2.64
c.uk/conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk).

1236
O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
(3H, s, Me), 7.30 (1H, tt, H-p, J = 6.9, 1.7 Hz), 7.50-7.41
(4H, m, H-o, H-m), 15.19 (1H, br.s, NH) ppm. 13C NMR
ꢀ77.1 (s, C-7-CF3) ppm. IR: 3250 (OH), 3205, 1600 (NH),
1690 (C=O), 1635, 1610 (C=N, C=C), 1145–1245 (C–F)
cmꢀ1. Analysis: Calc. for C16H13F3N4O4: C, 49.6; H, 3.4; F,
14.9; N, 14.7%. Found: C, 50.0; H, 3.4; F, 14.9; N,
14.6%.
1
(CDCl3) d: 31.0 (C-5), 117.3 (C-o), 117.5 (q, C-1, JC-
F = 292.5 Hz), 127.6 (C-p), 128.0 (C-3), 129.9 (C-m), 140.7
2
(C-i), 177.3 (q, C-2, JC-F = 32.3 Hz), 197.7 (q, C-4,
J = 1.3 Hz) ppm. 19F NMR (CDCl3) d: ꢀ71.3 (d, C-1-F3,
J = 1 Hz) ppm. IR (CHCl3, nujol mulls): 3470, 1595 (NH),
1700, 1670 (C=O), 1620, 1530 (C=N, C=C), 1120–1200 (C–
F) cmꢀ1. Analysis: Calc. for C11H9F3N2O2: C, 51.2; H, 3.5;
F, 22.1; N, 10.9%. Found: C, 51.3; H, 3.5; F, 22.4; N,
10.6%.
4.1.8. 6-Benzoyl-7-hydroxy-7-trifluoromethyl-4,7-
dihydro[1,2,4]triazolo[5,1-c][1,2,4]triazine (3d)
1
Yield, 59%; mp, 225–227 8C. H NMR (DMSO-d6) d:
7.55 (2H, m, H-m, J = 7.7 Hz), 7.67 (1H, t, H-p, J = 7.3 Hz),
7.80 (2H, d, H-o, J = 8.2 Hz), 8.10 (1H, s, H-2), 9.38 (1H, s,
NH), 13.35 (1H, br.s, OH) ppm. 13C NMR (DMSO-d6) d:
2
1
4.1.5. Ethyl-7-hydroxy-6-trifluoroacetyl-7-
trifluoromethyl-4,7-dihydropyrazolo[5,1-c]-
[1,2,4]triazine-3-carboxylate (3a)
82.2 (q, C-7, JC-F = 34.8 Hz), 121.8 (q, CF3, JC-
F = 289.9 Hz), 128.4 (C-o), 129.6 (C-m), 131.4 (C-i),
133.2 (C-p), 136.9 (C-6), 146.1 (C-2), 151.2 (C-3a),
188.7 (C-6-CO) ppm. 19F NMR (DMSO-d6) d: ꢀ77.3 (s,
C-7-CF3) ppm. IR: 3270 (OH), 3205, 1590 (NH), 1655 sh,
1650 (C=O), 1600, 1550, 1530 (C=N, C=C), 1100–1200 (C–
F) cmꢀ1. Analysis: Calc. for C12H8F3N5O2: C, 46.3; H, 2.6;
F, 18.3; N, 22.5%. Found: C, 46.5; H, 2.6; F, 18.0; N,
22.5%.
Yield after recrystallization from chloroform, 68%; mp,
208–210 8C. 1H NMR (DMSO-d6) d: 1.30 (3H, t, OCH2Me,
3
3JH-H = 7.0 Hz), 4.31 (2H, q, OCH2Me, JH-H = 7.0 Hz),
8.13 (1H, s, H-2), 9.65 (1H, s, NH), 13.65 (1H, br.s, OH)
ppm. 13C NMR (DMSO-d6) d: 14.3 (Me), 60.3 (OCH2), 80.1
(q, C-7, 2JC-F = 34.9 Hz), 97.6 (C-3), 116.1 (q, CO-CF3, 1JC-
1
F = 293.7 Hz), 119.0 (q, C-7-CF3, JC-F = 287.3 Hz), 126.7
(C-6), 136.6 (C-3a), 142.0 (C-2), 160.8 (C-3-CO), 173.8 (q,
4.1.9. 6-Acetyl-7-hydroxy-7-methyl-4,7-
dihydro[1,2,4]triazolo[5,1-c][1,2,4]triazine (3e)
2
C-6-CO, JC-F = 33.1 Hz) ppm. 19F NMR (DMSO-d6) d:
1
ꢀ77.9 (3F, s, C-7-CF3), ꢀ70.5 (3F, s, COCF3) ppm. IR: 3255
(OH), 3210, 1515 (NH), 1735 (CO2Et), 1690 (C=O), 1615,
1560 (C=N, C=C), 1250-1170 (C–F) cmꢀ1. Analysis: Calc.
for C11H8F6N4O4: C, 35.3; H, 2.2; F, 30.5; N, 15.0%. Found:
C, 35.3; H, 2.3; F, 30.4; N, 15.0%.
Yield, 70%; mp with decomposition, 200 8C. H NMR
(DMSO-d6) d: 1.91 (3H, s, Me), 2.09 (3H, s, COMe), 7.69
(1H, s, H-2), 7.80 (1H, s, NH), 12.28 (1H, br.s, OH) ppm. IR:
3240 (OH), 3190, 3130 (NH), 1690 (C=O), 1610, 1550
(C=N, C=C) cmꢀ1. Analysis: Calc. for C7H9N5O2: C, 43.1;
H, 4.7; N, 35.9%. Found: C, 43.5; H, 4.7; N, 35.5%.
4.1.6. Ethyl-6-acetyl-7-hydroxy-7-trifluoromethyl-4,7-
dihydropyrazolo[5,1-c][1,2,4]triazine-3-carboxylate
(3b)
4.1.10. 1-(p-Methoxyphenyl)azo-3,3,3-trifluoropropane-
1,2-dione 1-(40-methoxyphenyl)-hydrazone (4)
Yield after column chromatography (with dichloro-
1
Yield, 66%; mp, 152–154 8C. H NMR (DMSO-d6) d:
1.30 (3H, t, OCH2Me, 3JH-H = 7.1 Hz), 2.44 (3H, s, COMe),
methane as an eluent), 21%; mp, 157–158 8C. H NMR
1
3
4.29 (2H, q, OCH2Me, JH-H = 7.1 Hz), 8.03 (1H, s, H-2),
((CD3)2CO) d: 3.88 (6H, s, 2 OMe), 7.00 (4H, d, H-m,
J = 9.1 Hz), 7.66 (4H, d, H-o, J = 9.1 Hz), 16.10 (1H, s, NH)
ppm. 13C NMR (CDCl3) d: 55.7 (OMe), 115 (C-m), 117.5 (q,
C-3, 1JC-F = 290.7 Hz), 121.4 (C-o), 136.7 (C-1), 140.1 (C-
8.94 (1H, s, NH), 12.74 (1H, br.s, OH) ppm. 19F NMR
(DMSO-d6) d: ꢀ77.2 (t, C-7-CF3, J = 0.8 Hz) ppm. IR: 3270
(OH), 3210 (NH), 1700, 1680 (C=O), 1610, 1560 (C=N,
C=C), 1100–1235 (C–F) cmꢀ1. Analysis: Calc. for
C11H11F3N4O4: C, 41.3; H, 3.5; F, 17.8; N, 17.5%. Found:
C, 41.3; H, 3.5; F, 17.5; N, 17.3%.
2
i), 160.9 (C-p), 175.4 (q, C-2, JC-F = 33.8 Hz) ppm. 19F
NMR (CDCl3) d: ꢀ71.8 (s, CF3) ppm. IR: 3070 (NH), 1690
(C=O), 1580, 1500 (C=N, C=C, N=N), 1100–1200 (C–F)
cmꢀ1. Analysis: Calc. for C17H15F3N4O3: C, 53.7; H, 4.0; F,
15.0; N, 14.7%. Found: C, 53.6; H, 4.2; F, 15.0; N,
14.9%.
4.1.7. Ethyl-6-benzoyl-7-hydroxy-7-trifluoromethyl-4,7-
dihydropyrazolo[5,1-c][1,2,4]triazine-3-carboxylate
(3c)
1
Yield, 62%; mp, 183–185 8C. H NMR (DMSO-d6) d:
1.29 (3H, t, OCH2Me, JH-H = 7.0 Hz), 4.28 (2H, q,
4.2. Reactions of 1,2,3-triketones 2-(het)arylhydrazones
and 4,7-dihydroazolo[5,1-c][1,2,4]triazines with methyl
hydrazine and phenyl hydrazine
3
3
OCH2Me, JH-H = 7.0 Hz), 7.55 (2H, m, H-m), 7.66 (1H,
tt, H-p, J = 7.4, 1.3 Hz), 7.79 (2H, d, H-o, J = 8.2 Hz), 8.07
C
(1H, s, H-7), 9.32 (1H, br.s, NH), 12.65 (1H, s, OH) ppm. 13
NMR (DMSO-d6) d: 14.4 (Me), 59.9 (OCH2), 80.3 (q, C-7,
A mixture of 1,2,3-triketone 2-(het)arylhydrazone 2a,b,d
or 4,7-dihydroazolo[5,1-c][1,2,4]triazine 3a,d (2 mmol) and
methyl hydrazine or phenyl hydrazine (2 mmol) in 30 ml of
ethanol was refluxed for 8 h. The compounds 5b, 6a were
obtained as the orange crystals, pyrazoles 5a,c,d,e, 6b as
yellow powders.
1
2JC-F = 34.6 Hz), 95.4 (C-3), 122.0 (q, CF3, JC-
F = 290.8 Hz), 128.0 (C-o), 129.7 (C-m), 131.7 (C-i),
133.0 (C-p), 137.3 (C-6), 138.2 (C3a), 141.7 (C-2), 161.3
(C-3-CO), 188.9 (C-6-CO) ppm. 19F NMR (DMSO-d6) d:

O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
1237
5
4.2.1. 1,5-Dimethyl-4-phenylazo-3-
trifluoromethylpyrazole (5a)
H = 7.1 Hz), 4.18 (3H, q, NMe, JH-F = 1.3 Hz), 4.41 (2H,
q, OCH2Me, 3JH-H = 7.1 Hz), 8.12 (1H, s, H-3’), 10.52 (1H,
br.s, NH); cis-azo, d: 1.35 (3H, t, OCH2Me, 3JH-H = 7.1 Hz),
3.98 (3H, m, NMe), 4.29 (2H, q, OCH2Me, 3JH-H = 7.1 Hz),
8.04 (1H, s, H-30), 10.52 (1H, br.s, NH) ppm. 19F NMR
(CDCl3, a mix of isomers (trans-azo):(cis-azo) ꢁ3:1) trans-
azo, d: ꢀ63.8 (3F, s, C-3-CF3), ꢀ58.9 (3F, q, C-5-CF3, 5JF-
Yield after recrystallization from ethanol, 65%; mp, 93–
1
95 8C. H NMR (CDCl3) d: 2.62 (3H, s, Me), 3.89 (3H, s,
NMe), 7.43 (1H, tt, H-p, J = 7.5, 1.4 Hz), 7.49 (2H, dd, H-m,
J = 8.4, 7.5 Hz), 7.84 (2H, dd, H-o, J = 8.4, 1.4 Hz) ppm. 19
F
6
NMR (CDCl3) d: ꢀ62.6 (q, CF3, JF-H = 0.5 Hz) ppm. IR:
1555, 1483 (C=N, C=C), 1426 (N=N trans-isomer), 1120–
1200 (C–F) cmꢀ1. Analysis: Calc. for C12H11F3N4: C, 53.7;
H, 4.1; F, 21.3; N, 20.9%. Found: C, 53.5; H, 4.2; F, 21.0; N,
20.7%.
6
H = 1.3 Hz); cis-azo, d: ꢀ62.9 (3F, q, C-3-CF3, JF-
5
H = 0.5 Hz), ꢀ60.8 (3F, q, C-5-CF3, JF-H = 0.9 Hz) ppm.
IR (CCl4, nujol mulls): 3220, 1570 (NH), 1730, 1710
(CO2Et), 1552, 1492 (C=N, C=C), 1507 (N=N cis-isomer),
1426 (N=N trans-isomer), 1120–1200 (C–F) cmꢀ1. Analy-
sis: Calc. for C12H10F6N6O2: C, 37.5; H, 2.6; F, 29.7; N,
21.9%. Found: C, 37.6; H, 2.6; F, 29.8; N, 21.8%.
4.2.2. 4-( p-Methylphenylazo)-3,5-bis(trifluoromethyl)-
1-methylpyrazole (5b)
1
Yield after filtration, 78%; mp, 112–114 8C. H NMR
(CDCl3, a mix of isomers (trans-azo):(cis-azo) ꢁ95:5)
4.2.5. 3-(1-Methyl-5-phenyl-3-trifluoromethylpyrazol-4-
ylazo)-1H-1,2,4-triazole (5e)
5
trans-azo, d: 2.44 (3H, s, Me), 4.14 (3H, qq, NCH3, JH-
F = 1.2, 6JH-F = 0.5 Hz), 7.31 (2H, d, H-m, J = 8.7 Hz), 7.80
(2H, d, H-o, J = 8.7 Hz); cis-azo, d: 2.33 (3H, s, Me), 3.96
(3H, m, NCH3), 7.13 (2H, d, H-m, J = 8.5 Hz), 6.84 (2H, d,
H-o, J = 8.5 Hz) ppm. 13C NMR (CDCl3) trans-azo, d: 21.63
Yield after chloroform washing, 75%; mp, 235-236 8C.
1H NMR (DMSO-d6) d: 3.93 (3H, s, NMe), 7.60 (3H, m, H-
m, H-p), 7.68 (2H, m, H-o), 8.58 (1H, s, H-50), 14.57 (1H,
br.s, NH) ppm. 19F NMR (DMSO-d6) d: ꢀ61.4 (s, C-3-CF3)
ppm. IR (MeOH, nujol mulls): 3110, 1582 (NH), 1542, 1490
(C=N, C=C), 1422 (N=N trans-isomer), 1080–1220 (C–F)
cmꢀ1. Analysis: Calc. for C13H10F3N7: C, 48.6; H, 3.1; F,
17.7; N, 30.5%. Found: C, 48.5; H, 3.4; F, 17.5; N,
30.6%.
1
(Me), 40.2 (q, NMe, J = 2.6 Hz), 119.4 (q, C-5-CF3, JC-
1
F = 271.4 Hz), 120.4 (q, C-3-CF3, JC-F = 269 Hz), 123.2
(C-o), 129.5 (q, C-5, 2JC-F = 39.9 Hz), 129.8 (C-m), 132.07
2
(q, C-3, JC-F = 39.7 Hz), 137.1 (unresolv. m, C-4), 143.15
(C-p), 150.7 (C-i); cis-azo, d: 21.62 (Me), 39.6 (q, NMe,
J = 2.1 Hz), 120.7 (C-o), 129.33 (C-m), 129.34 (q, C-5, 2JC-
F = 39.5 Hz), 132.09 (q, C-3, 2JC-F = 39.7 Hz), 139.9 (C-4),
143.14 (C-p), 151.2 (C-i) ppm. 19F NMR (CDCl3, a mix of
isomers (trans-azo):(cis-azo) ꢁ95:5) trans-azo, d: ꢀ63.2
(3F, q, C-3-CF3, 6JF-H = 0.5 Hz), ꢀ58.8 (3F, q, C-5-CF3, 5JF-
4.2.6. 4-( p-Tolylazo)-3,5-bis(trifluoromethyl)-1-
phenylpyrazole (6a)
1
Yield after filtration, 72%; mp, 118–120 8C. H NMR
6
(CDCl3, a mix of isomers (trans-azo):(cis-azo) ꢁ95:5)
trans-azo, d: 2.45 (3H, s, Me), 7.33 (2H, d, H-m-C6H4,
J = 8.3 Hz), 7.51-7.57 (5H, m, N-Ph), 7.84 (2H, d, H-o-
C6H4, J = 8.3 Hz); cis-azo, d: 2.37 (3H, s, Me), 6.94 (2H, d,
H-m-C6H4, J = 8.3 Hz), 7.58–7.60 (5H, m, N-Ph), 7.18 (2H,
d, H-o-C6H4, J = 8.3 Hz) ppm. 19F NMR (CDCl3, a mix of
isomers (trans-azo):(cis-azo) ꢁ95:5) trans-azo, d: ꢀ63.1
(3F, s, C-3-CF3), ꢀ56.5 (3F, s, C-5-CF3); cis-azo, d: ꢀ62.8
(3F, s, C-3-CF3), ꢀ58.4 (3F, s, C-5-CF3) ppm. IR (CCl4,
nujol mulls): 1585, 1555, 1502, 1483 (C=N, C=C), 1447
(N=N trans-isomer), 1220–1120 (C–F) cmꢀ1. Analysis:
Calc. for C18H12F6N4: C, 54.3; H, 3.0; F, 28.6; N, 14.1%.
Found: C, 54.2; H, 3.1; F, 28.8; N, 14.1%.
H = 1.2 Hz); cis-azo, d: ꢀ62.7 (3F, q, C-3-CF3, JF-
5
H = 0.5 Hz), ꢀ60.8 (3F, q, C-5-CF3, JF-H = 0.9 Hz) ppm.
IR (CCl4, nujol mulls): 1600, 1560, 1502, 1483 (C=N, C=C),
1426 (N=N trans-isomer), 1200-1140 (C–F) cmꢀ1. Analy-
sis: Calc. for C13H10F6N4: C, 46.4; H, 3.0; F, 33.9; N, 16.7%.
Found: C, 46.3; H, 3.0; F, 33.2; N, 16.5%.
4.2.3. 4-(1,5-Dimethyl-3-trifluoromethylpyrazol-4-
ylazo)-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (5c)
Yield after column chromatography (with chloroform as
an eluent), 67%; mp, 222-223 8C. 1H NMR (CDCl3) d: 2.57,
2.62 (6H, 2 s, C-5-Me, C-30-Me), 3.32 (3H, s, N-20-Me), 3.84
(3H, q, N-1-Me, J = 0.5 Hz), 7.36 (3H, m, H-o, H-p), 7.48
(2H, dd, H-m, J = 8.8, 7.0 Hz) ppm. 19F NMR (CDCl3) d:
ꢀ63.1 (q, CF3, 6JF-H = 0.5 Hz) ppm. IR: 1660 (C=O), 1595,
1542, 1490 (C=C, C=N), 1432 (N=N trans-isomer), 1130–
1190 (C–F) cmꢀ1. Analysis: Calc. for C17H17F3N6O: C,
54.0; H, 4.5; F, 15.1; N, 22.2%. Found: C, 53.9; H, 4.7; F,
14.52; N, 22.3%.
4.2.7. 3-(1,5-Diphenyl-3-trifluoromethylpyrazol-4-
ylazo)-1H-1,2,4-triazole (6b)
Yield after chloroform washing, 71%; mp, >250 8C. 1H
NMR (DMSO-d6/CCl4) d: 7.36–7.46 (10H, m, 2 Ph), 8.49
(1H, s, H- H-50), 14.46 (1H, br.s, NH) ppm. 19F NMR
(DMSO-d6/CCl4) d: ꢀ62.3 (s, CF3) ppm. IR: 3100, 1585
(NH), 1540, 1490, 1475 (C=N, C=C), 1426 (N=N trans-
isomer), 1120–1180 (C–F) cmꢀ1. UV (methanol), lmax (e):
205 (22600), 255 (10460), 310 (8640), 436 sh (800) nm.
Analysis: Calc. for C18H12F3N7: C, 56.4; H, 3.2; F, 14.9; N,
25.6%. Found: C, 56.4; H, 3.1; F, 14.7; N, 25.8%.
4.2.4. Ethyl-1H-3-[3,5-bis(trifluoromethyl)-1-
methylpyrazol-4-ylazo]pyrazole-4-carboxylate (5d)
Yield after recrystallization from hexane, 58%; mp, 123–
125 8C. 1H NMR (CDCl3, a mix of isomers (trans-azo):(cis-
3
azo) ꢁ3:1) trans-azo, d: 1.37 (3H, t, OCH2Me, JH-

1238
O.G. Khudina et al. / Journal of Fluorine Chemistry 126 (2005) 1230–1238
4.3. 3,5-Bis(trifluoromethyl)-4,5-dihydro-5-hydroxy-1-
methylpyrazole (7)
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1
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2
4
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4
4
3.46 (1H, br.s, OH) ppm. 19F NMR (CDCl3) d: ꢀ80.6 (3F,
dqd, C-5-CF3, JF-Hb = 1.3, JF-H = 4JF-Ha = 0.7 Hz), ꢀ67.6
4
5
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.
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[8] S.P. Singh, J.K. Kapoor, D. Kumar, M.D. Threadgill, J. Fluorine
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Analysis: Calc. for C6H6F6N2O: C, 30.5; H, 2.6; F, 48.3; N,
11.9%. Found: C, 30.7; H, 2.5; F, 48.4; N, 11.8%.
[9] J.C. Sloop, C.L. Bumgardner, W.D. Loehle, J. Fluorine Chem. 118
(2002) 135–147.
[10] L.J. Bellamy, Advances in infrared group frequencies, Methuen & Co.
Ltd., Bungay, Suffolk, 1968.
Acknowledgements
[11] M.D. Threadgill, A.K. Heer, B.G. Jones, J. Fluorine Chem. 65 (1993)
21–23.
This work was supported by Russian Foundation for
Basic Research (Grant 03-03-33118), the State Programme
for supporting leading scientific schools of Russian
Federation (Grant 1766.2003.3) and the Russian Science
Support Foundation.
[12] J.C. Sloop, C.L. Bumgardner, W.D. Loehle, J. Fluorine Chem. 118
(2002) 135–147.
[13] G.M. Scheldrik, SHELXS 97 and SHELXL 97, University of Gottin-
gen, Germany, 1997.