Synthesis and spectroscopic investigation of the new polyfluoroalkyl- containing indazolones

Article abstract of DOI:10.1134/S1070363208100241

Reaction of 2-perfluoroacylcycloalkane-1,3-diones and their enol methyl esters with N,N-dinucleophiles such as 4-fluorophenylhydrazine hydrochloride and pentafluorophenylhydrazine results in formation of polyfluoroalkyl-containing 1-aryl-3-polyfluoroalkyl

Full text of DOI:10.1134/S1070363208100241

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 10, pp. 1954–1963. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © T.S. Khlebnikova, V.G. Isakova, A.V. Baranovskii, F.A. Lakhvich, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78,
No. 10, pp. 1718–1727.
Synthesis and Spectroscopic Investigation
of the New Polyfluoroalkyl-containing Indazolones
T. S. Khlebnikova, V. G. Isakova, A. V. Baranovskii, and F. A. Lakhvich
Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus,
ul. Acad. Kuprevicha 5/2, Minsk, 220141 Belarus
e-mail: khlebnicova@iboch.bas-net.by
Received February 28, 2008
Abstract―Reaction of 2-perfluoroacylcycloalkane-1,3-diones and their enol methyl esters with N,N-
dinucleophiles such as 4-fluorophenylhydrazine hydrochloride and pentafluorophenylhydrazine results in
formation of polyfluoroalkyl-containing 1-aryl-3-polyfluoroalkyl-6,7-dihydro-1Н-indazol-4(5)Н-ones and 2-
aryl-3-polyfluoroalkyl-6,7-dihydro-2Н-indazol-4(5)Н-ones respectively. Structure of compounds obtained was
proved with IR, 1Н, 13С, 19F, 15N NMR, and mass-spectrometric methods.
DOI: 10.1134/S1070363208100241
Indazoles form a significant class of organic
compounds many of which display antiphlogistic,
analgesic, antiviral and others forms of physiological
activities [1–4]. Presently the synthetic methods for
various fluorine-containing polyfunctional heterocyclic
structures such as potential drugs and plant protection
agents are intensively developed [5, 6]. It is evident
that selective incorporation of the phosphorus atoms
and fluoroalkyl groups into the aromatic ring or
heterocyclic system can reveal an important effect on
the physical and chemical properties, reactivity and
biological activity of these compounds. By now the
different strategies to accomplish these aims are
developed [7–9]. Use of the polycarbonyl “structural
blocks” is the one of the most perspective way for design
of biological active fluoroalkyl-containing organic
compounds such as acyclic and cyclic fluoroalkyl-
containing β-diketones [10–12] and acyclic β,β'-
triketones [13], although their reaction with N-nucleo-
philes and N,N-dinucleophiles proceeds ambi-guously.
Often the mixture of regioisomeric products was
formed and in case of β,β'-triketones the acidic
cleavage was observed. Unlike the non-fluorinated
cyclic β,β'-triketones chemical properties of which are
rather widely examined [14], using the cyclic fluorine-
containing β,β'-tricarbonyl compounds as block-
syntons was limited by the absence of synthetic
method for the preparation of the mentioned
compounds. Recently we have developed an effective
one-stage synthesis of 2-perfluoroalkanoylcyclo-
hexane-1,3-diones I by С-acylation of cyclohexane-
1,3-diones with N-perfluoroacylimidazoles [15, 16]. It
provided availability of such compounds and allowed
the further investigation of their reactivity to be carried
out. Chemical transformations of β,β'-triketones I
occurring as enol forms can touch such reaction
centers as exo- and endo-cyclic carbonyl groups.
Owing to the availability of three electrophilic centers,
they can be used for synthesis of a great variety of
heterocyclic systems with polyfluoroalkyl groups.
We examined reaction of the cyclic β,β'-triketones
Iа–If containing perfluoroacyl groups and their methyl
enol esters IIa–IIf, with fluorine-containing N,N-
dinucleophilic reagents such as 4-fluorophenylhyd-
razine hydrochloride and pentafluorophenylhydrazine
for the purpose of obtaining new polyfluoroalkyl-
containing indazolones. It is established that the
treatment of 2-perfluoroalkanoylcyclohexane-1,3-di-
ones Iа–If with the little excess of equimolar mixture
of 4-fluorophenylhydrazine hydrochloride and sodium
hydroxide in ethanol during 8 h at room temperature
results in a one reaction product, indazolone IIIа–IIIl,
formed through heterocyclization of the intermediate
hydrazone IIа–IIl. Under the same reaction conditions,
reaction of fluorine-containing β,β'-triketones Id–If
with pentafluorophenylhydrazine gives indazolones
IIIl–IIIl, but in the case of the dimedone series
compounds Iа–Ic only hydrazones IIg–IIi were
obtained. Indazolones IIIg–IIIi were obtained at the
1954

SYNTHESIS AND SPECTROSCOPIC INVESTIGATION
1955
Scheme 1.
H
N
Ar
O
N
Ar
N1 2N
3
RF
RF
7a
3a
7
6
R
R
NH2NHAr
4
5
O
O
O
O
O
R
R
IIIа_IIIl
IIа_IIl
RF
R
1. Me2SO4
2.
R
NH2NHAr
Iа_If
H
Ar
RF
N
Ar
N
O
O
N1 2N
O
O
3
RF
7a
3a
RF
7
6
R
R
R
R
4
5
O
OMe
IVа_IVf
R
R
Vа_Vl
VIа_VIl
I, IV, R = Me: RF = CF3 (a), C2F5 (b), C3F7 (c); R = H: RF = CF3 (d), C2F5 (e), C3F7 (f); II, III, V, VI, Ar = 4-FC6H4: R = Me: RF = CF3
(а), C2F5 (b), C3F7 (c); R = H: RF = CF3 (d), C2F5 (e), C3F7 (f); Ar = C6F5: R = Me: RF = CF3 (g), C2F5 (h), C3F7 (i); R = H: RF = CF3 (j),
C2F5 (k), C3F7 (l).
reflux of reaction mixture in ethanol for 10 h (Scheme
1).
zolones IIIа–IIIl in 65–80% yield (Table 1). Contrary
to acyclic and cyclic 1,3-diketones, reacting
ambiguously with N-nucleophiles and N,N-dinucleo-
philes often with foration off a mixture of regioisomeric
products, this reaction is regioselective and gives one
product always.
Thus under these conditions condensation of 2-
perfluoroalkanoylcyclohexane-1,3-diones Iа–If with
fluorine-containing phenylhydrazines proceeds at the
more electrophilic exo-cyclic carbonyl group, that is, at
the carbonyl linked with polyfluoroalkyl group, that
leads to formation of hydrazones IIа–IIl. Intramo-
lecular cyclization of the latters gives rise to inda-
To obtain polyfluoroalkyl substituted indazolones,
which are structurally isomeric to indazolones IIIа-
IIIl, direction of nucleophilic attack of phenyl-
Table 1. Yields, melting points, elemental analysis and mass-spectral data of 1-aryl-3-polyfluoroalkyl-6,7-dihydro-1Н-
indazol-4(5)Н-ones IIIа–IIIl
Found, %
Н
Calculated, %
Comp.
no.
mp,
R
RF
Ar
Yield, %
Formula
M+
°С
С
N
С
Н
N
CH3
CH3
CH3
H
CF3
4-FC6H4
4-FC6H4
4-FC6H4
4-FC6H4
74
73
71
75
73–77
58.79
54.16
50.82
56.48
4.25
8.49
7.35
6.63
9.47
C16H14F4N2O
C17H14F6N2O
C18H14F8N2O
C14H10F4N2O
58.90
54.26
50.71
56.38
4.32
3.75
3.31
3.38
8.59
7.44
6.57
9.39
326
376
426
298
IIIa
IIIb
IIIc
IIId
C2F5
C3F7
CF3
103–105
107–110
123–127
3.69
3.37
3.42
H
H
C2F5
C3F7
4-FC6H4
4-FC6H4
65
72
119–122
99–102
51.61
48.35
2.81
2.59
7.96
7.11
C15H10F6N2O
C16H10F8N2O
51.73
48.25
2.89
2.53
8.04
7.03
348
398
IIIe
IIIf
CH3
CH3
CH3
H
CF3
C6F5
C6F5
C6F5
C6F5
C6F5
C6F5
75
72
70
80
78
75
112–114
96–99
48.12
45.46
43.28
45.51
42.78
40.95
2.49
2.29
1.96
1.65
1.41
1.28
6.96
6.32
5.56
7.63
6.60
5.91
C16H10F8N2O
48.25
2.53
2.25
2.02
1.63
1.44
1.29
7.03
6.25
5.62
7.57
6.67
5.96
398
448
498
370
420
470
IIIg
IIIh
IIIi
IIIj
IIIk
IIIl
C2F5
C3F7
CF3
C17H10F10N2O 45.55
C18H10F12N2O 43.39
74–77
109–112
106–109
66–70
C14H6F8N2O
C15H6F10N2O
C16H6F12N2O
45.42
42.88
40.87
H
C2F5
C3F7
H
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

1956
KHLEBNIKOVA et al.
hydrazine should be changed. This change can be
accomplished by initial transformation of 2-
perfluoroalkanoylcyclohexane-1,3-diones Iа–If into
the enol methyl esters IVа–IVf and further treatment
of the latters with phenylhydrazine. A number of
methods was proposed to obtain enol methyl esters of
non-fluorinated 2-acylcyclohexane-1,3-diones, including
alkylation of their silver salts with methyl iodide [17]
or of sodium and tetrabutylammonium salts with
dimethylsulfate [18]. It turned out that O-alkylation of
tetrabutylammonium salts with dimethylsulfate is the
best variation for the synthesis of 2-perfluoro-
cyclohexane-1,3-diones Iа–Iе. Enol methyl esters
IVa–IVf were used in reaction with phenylhydrazines
without isolation since they are unstable and easily
hydrolyzed to initial triketones during isolation and
storage.
intramolecular cyclization resulted in indazolones
VIа–VIl in 57–75% yield (Table 2).
Structures of the all synthesized compounds IIj–IIl,
IIIа-IIIl and VIа–VIl were confirmed by elemental
analysis, IR, mass- and 1Н, 13С, 19F NMR spectroscopy
data (Tables 1–4). In the IR spectra of hydrazones IIj–
IIl which are in the enhydrazine form there are two
absorption bands, of carbonyl group and double bond,
observed in the ranges 1570–1595 and 1535–1545 cm–1,
1
respectively, and in the Н NMR spectrum (CDCl3)
two singlets are found at δ 7.46 (N–H) and δ 8.26–9.29
(N–H) ppm [19]. In the mass-spectra of compounds
IIk–IIl peaks of the molecular ion are not found, but
peaks of secondary ions related to a loss of water
molecule are observed.
Indazolones IIIа–IIIl and VIа–VIl differ
essentially by their physico-chemical properties. The
IR spectra of compounds IIIа–IIIl are characterized
by strong absorption bands in the range of 1685–
1710 cm–1 (conjugated carbonyl) and 1500–1530 cm–1
(С=С, С=N). In the IR spectra of indazolones VIа–VIl
strong absorption bands are at 1690–1715 cm–1
(conjugated carbonyl), at 1550–1570 сm–1 (С=С) and
at 1505–1520 cm–1 (С=N). The IR spectra data of
compounds IIIа–IIIl and VIа–VIl are consistent well
with data reported in literature for indazolones
obtained from 2-acetylcyclohexane-1,3-diones [20]
and methyl ester of 2-acetylcyclohexane-1,3-dione
[21]. In the 13C NMR spectra of compounds IIIа–IIIl
In view of aforesaid, we carried out synthesis of
polyfluoroalkyl substituted indazolones VIа–VIl
transforming 2-perfluoroalkanoylcyclohexane-1,3-di-
ones Iа–If into tetrabutylammonium salts by the action
of tetrabutylammonium hydroxide in methanol,
alkylation of the salts with dimethylsulfate and
treatment the reaction mixture obtained after solvent
removal with the equivalent quantity of fluorophenyl-
hydrazine in ethanol at room temperature. As for non-
fluorinated 2-acetylcyclohexane-1,3-diones, reaction
of enol methyl esters IVа–IVf with phenylhydrazine
proceeded by the mechanism of vinylogous
substitution to form hydrazones Vа–Vl, which undergo
Table 2. Yields, melting points, elemental analysis and mass-spectra data of 2-aryl-3-perfluoroalkyl-6,7-dihydro-1Н-indazol-
4(5)Н-ones VIа–VIl
Found, %
Н
Calculated, %
Comp.
no.
Yield,
%
mp,
R
RF
Ar
Formula
M+
°С
С
N
С
Н
N
CH3 CF3
CH3 C2F5
CH3 C3F7
4-FC6H4
4-FC6H4
4-FC6H4
4-FC6H4
4-FC6H4
4-FC6H4
C6F5
57
58
57
63
68
75
65
63
61
69
72
74
79–82
87–91
59.13
54.11
50.85
56.29
51.63
48.16
48.15
45.67
43.24
45.36
42.76
40.98
4.39
3.67
3.38
3.33
2.83
2.47
2.45
2.31
1.93
1.61
1.40
1.31
8.66
7.31
6.67
9.32
7.95
6.94
6.95
6.34
5.51
7.50
6.58
6.01
C16H14F4N2O
C17H14F6N2O
C18H14F8N2O
C14H10F4N2O
C15H10F6N2O
C16H10F8N2O
C16H10F8N2O
C17H10F10N2O
C18H10F12N2O
C14H6F8N2O
C15H6F10N2O
C16H6F12N2O
58.90
54.26
50.71
56.38
51.73
48.25
48.25
45.55
43.39
45.42
42.88
40.87
4.32
3.75
3.31
3.38
2.89
2.53
2.53
2.25
2.02
1.63
1.44
1.29
8.59
7.44
6.57
9.39
8.04
7.03
7.03
6.25
5.62
7.57
6.67
5.96
326
376
426
298
348
398
398
448
498
370
420
470
VIа
VIb
VIc
VId
VIe
VIf
VIg
VIh
VIi
71–74
H
H
H
CF3
71–74
C2F5
C3F7
137–140
103–107
77–79
CH3 CF3
CH3 C2F5
CH3 C3F7
C6F5
83–86
C6F5
75–78
H
H
H
CF3
C6F5
72–75
VIj
VIk
VIl
C2F5
C3F7
C6F5
117–120
63–66
C6F5
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

SYNTHESIS AND SPECTROSCOPIC INVESTIGATION
Table 3. IR, 1Н and 19F NMR spectra of compounds IIIа–IIIl and VIа–VIl
Comp. IR spectrum,
1957
1Н NMR spectrum (CDCl3), δ, ppm. (J, Hz)
19F NMR spectrum (CDCl3), δ, ppm (J, Hz)
no.
ν, cm–1
1700,
1.13 s (6H, 2CH3), 2.48 s (2Н, CH2, С7), 2.83 s (2H, CH2, –63.4 s (3F, CF3), –110.1 m (F, CaromF)
IIIa
1510 br
С5), 7.51 m (5H, Harom
)
1700, 1530, 1.13 s (6H, 2CH3), 2.48 s (2Н, CH2, С7), 2.80 s (2Н, CH2, –83.2 br.s (3F, CF3), –111.1 m (1F, CaromF), –111.5
IIIb
IIIc
IIId
1510
С5), 7.25 m (2H, Harom), 7.50 m (2H, Harom
)
br.s (2F, CF2)
1700, 1520, 1.12 s (6H, 2CH3), 2.48 s (2Н, CH2, С7), 2.79 s (2Н, CH2, –80.4 t (3F, CF3, J 9), –109.6 m (2F, CF2), –111.0 m
1500
1690,
С5), 7.24 m (2H, Harom), 7.49 m (2H, Harom
)
(1F, CaromF), –125.8 m (2F, CF2)
2.21 quint (2H, CH2, C6, J 6.2), 2.61 t (2H, CH2, С7, J 6.2), –63.5 s (3F, CF3), –111.1 m (F, CaromF)
2.95 t (2H, CH2, С5, J 6.2), 7.25 m (2H, Harom), 7.51 m (2H,
1510 br
Harom
1690, 1530, 2.20 quint (2H, CH2, C6, J 6.2), 2.60 t (2H, CH2, С7, J 6.2), –83.2 br.s (3F, CF3), –111.2 m (1F, CaromF), –111.4
1510
2.96 t (2H, CH2, С5, J 6.2), 7.24 m (2H, Harom), 7.50 m (2H, br.s (2F, CF2)
Harom
1690, 1530, 2.20 quint (2H, CH2, C6, J 6.2), 2.60 t (2H, CH2, С7, J 6.2), –80.4 t (3F, CF3, J 9), –109.4 m (2F, CF2), –111.1 m
)
IIIe
IIIf
)
1510
2.96 t (2H, CH2, С5, J 6.2), 7.25 m (2H, Harom), 7.51 m (2H, (1F, CaromF), –125.7 m (2F, CF2)
Harom
1.16 s (6H, 2CH3), 2.51 s (2Н, CH2, С7), 2.62 s (2H, CH2, –63.9 s (3F, CF3), –144.7 m (2F, CaromF), –148.4 t (1F,
С5)
CaromF, J 21), –159.1 m (2F, CaromF)
1.15 s (6H, 2CH3), 2.51 s (2Н, CH2, С7), 2.62 s (2H, CH2, –83.4 br.s (3F, CF3), –112.0 br.s (2F, CF2), –144.7 m
)
1695,
1520 br
1695,
IIIg
IIIh
1535 br
С5)
(2F, CaromF), –148.4 t (1F, CaromF, J 21), –159.0 m
(2F, CaromF)
1700,
1.15 s (6H, 2CH3), 2.51 s (2Н, CH2, С7), 2.62 s (2H, CH2, 80.5 t (3F, CF3, J 9), –110.3 m (2F, CF2), –126.3 m
IIIi
1540 br
С5)
(2F, CF2), –144.8 m (2F, CaromF), –148.3 t (1F, CaromF,
J 21), –159.0 m (2F, CaromF)
1700,
1530 br
1700,
2.27 quint (2H, CH2, C6, J 6.2), 2.64 t (2H, CH2, С7, 64.1 s (3F, CF3), –144.7 m (2F, CaromF), –148.4 t (1F,
IIIj
J 6.2), 2.79 t (2H, CH2, С5, J 6.2)
2.26 quint (2H, CH2, C6, J 6.2), 2.64 t (2H, CH2, С7, –83.2 br.s (3F, CF3), –111.9 br.s (2F, CF2), –144.5 m
CaromF, J 21), –159.2 m (2F, CaromF)
IIIk
1540 br
J 6.2), 2.79 t (2H, CH2, С5, J 6.2)
(2F, CaromF), –148.4 t (1F, CaromF, J 21), –159.1 m
(2F, CaromF)
1710,
2.26 quint (2H, CH2, C6, J 6.2), 2.64 t (2H, CH2, С7, 80.5 t (3F, CF3, J 9), –110.1 m (2F, CF2), –126.1 m
IIIl
1540 br
J 6.2), 2.80 t (2H, CH2, С5, J 6.2)
(2F, CF2), –144.7 m (2F, CaromF), –148.5 t (1F, CaromF,
J 21), –159.2 m (2F, CaromF)
1685,
1.16 s (6H, 2CH3), 2.50 s (2Н, CH2, С7), 2.80 s (2H, CH2, –56.4 s (3F, CF3), –110.3 m (F, CaromF)
VIа
VIb
VIc
VId
1560, 1515 С5), 7.20 m (2H, Harom), 7.43 m (2H, Harom
)
1695,
1.15 s (6H, 2CH3), 2.49 s (2Н, CH2, С7), 2.81 s (2H, CH2, –83.7 br.s (3F, CF3), –107.9 m (1F, CaromF), –110.1 m
1550, 1520 С5), 7.18 m (2H, Harom), 7.37 m (2H, Harom
)
(2F, CF2)
1690,
1.15 s (6H, 2CH3), 2.49 s (2Н, CH2, С7), 2.81 s (2H, CH2, 80.4 t (3F, CF3, J 9), –104.7 m (2F, CF2), –110.1 m
1550, 1520 С5), 7.17 m (2H, Harom), 7.38 m (2H, Harom
)
(F, CaromF), –124.4 m (2F, CF2)
1690,
1560, 1520 2.94 t (2H, CH2, С5, J 6.2), 7.20 m (2H, Harom), 7.42 m (2H,
Harom
2.20 quint (2H, CH2, C6, J 6.2), 2.63 t (2H, CH2, С7, J 6.2), –83.6 br.s (3F, CF3), –107.8 m (1F, CaromF), –110.1 m
1550, 1520 2.95 t (2H, CH2, С5, J 6.2), 7.17 m (2H, Harom), 7.35 m (2H, (2F, CF2)
Harom
2.21 quint (2H, CH2, C6, J 6.2), 2.63 t (2H, CH2, С7, J 6.2), 80.4 t (3F, CF3, J 9), –104.6 m (2F, CF2), –110.1 m
1545, 1520 2.96 t (2H, CH2, С5, J 6.2), 7.17 m (2H, Harom), 7.36 m (2H, (F, CaromF), –124.2 m (2F, CF2)
Harom
2.20 quint (2H, CH2, C6, J 6.2), 2.63 t (2H, CH2, С7, J 6.2), –56.5 s (3F, CF3), –110.1 m (F, CaromF)
)
1695,
VIe
VIf
)
1700,
)
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

1958
KHLEBNIKOVA et al.
Table 3. (Contd.)
Comp. IR spectrum,
1Н NMR spectrum (CDCl3), δ, ppm. (J, Hz)
19F NMR spectrum (CDCl3), δ, ppm (J, Hz)
no.
ν, cm–1
1715,
1.17 s (6H, 2CH3), 2.53 s (2Н, CH2, С7), 2.84 s (2H, 59.5 s (3F, CF3), –145.3 m (2F, CaromF), –148.7 t (1F, CaromF, J
VIg
1585, 1545 CH2, С5)
21), –160.1 m (2F, CaromF)
1.16 s (6H, 2CH3), 2.52 s (2Н, CH2, С7), 2.85 s (2H, –83.2 br.s (3F, CF3), –111.6 br.s (2F, CF2), –144.6 m (2F,
1565, 1540 CH2, С5)
CaromF), –148.5 t (1F, CaromF, J 21), –160.3 m (2F, CaromF)
1705,
1.16 s (6H, 2CH3), 2.52 s (2Н, CH2, С7), 2.85 s (2H, 80.4 t (3F, CF3, J 9), –108.5 m (2F, CF2), –125.7 m (2F, CF2),
1560, 1540 CH2, С5)
1705,
VIh
VIi
–144.5 m (2F, CaromF), –148.5 t (1F, CaromF, J 21), –160.6 m
(2F, CaromF)
1700,
1570, 1535 J 6.3), 2.98 t (2H, CH2, С5, J 6.3)
1700,
2.24 quint (2H, CH2, C6, J 6.3), 2.67 t (2H, CH2, С7, –84.3 br.s (3F, CF3), –111.5 br.s (2F, CF2), –144.6 m (2F,
1560, 1535 J 6.3), 2.99 t (2H, CH2, С5, J 6.3)
CaromF), –148.5 t (1F, CaromF, J 21), –160.5 m (2F, CaromF)
1705,
2.26 quint (2H, CH2, C6, J 6.3), 2.67 t (2H, CH2, С7, 80.8 t (3F, CF3, J 9), –108.6 m (2F, CF2), –125.7 m (2F, CF2),
1560, 1540 J 6.3), 2.80 t (2H, CH2, С5, J 6.3)
2.25 quint (2H, CH2, C6, J 6.3), 2.67 t (2H, CH2, С7, 59.7 с (3F, CF3), –145.5 m (2F, CaromF), –148.8 t (1F, CaromF, J
VIj
VIk
VIl
21), –160.2 m (2F, CaromF)
–144.9 m (2F, CaromF), –149.1 t (1F, CaromF, J 21), –161.2 m
(2F, CaromF)
Table 4. 13С NMR spectra of compounds IIIа–IIIl and VIа–VIl
Comp.
13С NMR spectrum (CDCl3), δ, ppm (JC–F, Hz)
no.
28.3 (CH3), 35.7 (C6), 36.8 (C7), 52.3 (C5), 116.0 (C3a), 116.7 d (Cаrom, 2J 23), 120.4 q (CF3, 1J 270), 126.3 d (Cаrom, 3J 9), 133.8 d
(Cаrom, 4J 3), 140.5 q (C3, 2J 40), 150.6 (C7a), 162.7 (CаromF, 1J 251), 189.9 (C4)
IIIа
2
2
1
28.2 (CH3), 35.5 (C6), 37.0 (C7), 52.6 (C5), 110.5 t. q (CF2, 1J 253, J 39), 116.7 d (Cаrom, J 23), 117.4 (C3a), 119.0 q. t (CF3, J
IIIb
IIIc
286, 2J 37), 126.3 d (Cаrom, 3J 9), 133.9 d (Cаrom, 4J 3), 139.6 t (C3, 2J 31), 150.6 (C7a), 162.7 d (CаromF, 1J 251), 189.4 (C4)
1
1
2
2
28.2 (CH3), 35.4 (C6), 37.0 (C7), 52.7 (C5), 108.6 t. m (CF2, J 267), 112.5 t. t (CF2, J 256, J 32), 116.7 d (Cаrom, J 23), 117.4
(C3a), 118.1 q. t (CF3, 1J 287, 2J 33), 126.3 d (Cаrom, 3J 9), 133.9 d (Cаrom, 4J 3), 139.6 t (C3, 2J 31), 150.6 (C7a), 162.7 d (CаromF, 1J
251), 189.4 (C4)
23.1 (C6), 23.2 (C7), 38.3 (C5), 116.7 d (Cаrom, 2J 23), 117.0 (C3a),120.4 q (CF3, 1J 270), 126.2 d (Cаrom, 3J 9), 133.8 d (Cаrom, 4J 2),
140.7 q (C3, 2J 40), 151.4 (C7a), 162.6 (CаromF, 1J 251), 190.4 (C4)
IIId
IIIe
IIIf
1
2
2
1
23.1 (C6), 23.2 (C7), 38.3 (C5), 110.5 t. q (CF2, J 253, J 39), 116.7 d (Cаrom, J 23), 118.3 (C3a), 118.9 q. t (CF3, J 287, 2J 37),
126.2 d (Cаrom, 3J 9), 133.9 d (Cаrom, 4J 3), 139.6 t (C3, 2J 31), 151.5 (C7a), 162.7 d (CаromF, 1J 251), 189.8 (C4)
2
23.1 (C6), 23.2 (C7), 38.3 (C5), 108.7 t. m (CF2, 1J 267), 112.6 t. t (CF2, 1J 256, 2J 33), 116.7 d (Cаrom, J 23), 118.1 q. t (CF3, 1J
287, 2J 33), 118.5(C3a), 126.3 d (Cаrom, 3J 9), 133.9 d (Cаrom, 4J 3), 139.8 t (C3, 2J 30), 151.5 (C7a), 162.7 d (CаromF, 1J 251), 189.6
(C4)
28.1 (CH3), 35.2 (C6), 35.7 (C7), 52.3 (C5), 112.7 m (Cаrom), 116.2 (C3a), 119.9 q (CF3, 1J 270), 138.1 d.m (CаromF, 1J 254), 142.5 q
(C3, 2J 40), 143.1 d.m (CаromF, 1J 261), 143.8 d.m (CаromF, 1J 257), 154.4 (C7a), 189.3 (C4)
28.1 (CH3), 35.2 (C6), 35.7 (C7), 52.3 (C5), 110.1 t. q (CF2, 1J 253, 2J 40), 112.8 m (Cаrom), 117.5 (C3a), 118.7 q. t (CF3, 1J 287, 2J
36), 138.1 d.m (CаromF, 1J 254), 141.7 t (C3, 2J 31), 143.2 d.m (CаromF, 1J 258), 143.7 d.m (CаromF, 1J 258), 154.2 (C7a), 188.7 (C4)
IIIg
IIIh
IIIi
1
1
28.0 (CH3), 35.3 (C6), 35.4 (C7), 52.6 (C5), 108.8 t. m (CF2, J 267), 112.1 t. t (CF2, J 257, 2J 32), 112.8 m (Cаrom), 117.7 (C3a),
117.9 q. t (CF3, J 287, J 34), 138.1 d.m (CаromF, J 256), 141.7 t (C3, J 30), 143.1 d.m (CаromF, J 261), 143.7 d.m (CаromF, J
1
2
1
2
1
1
258), 154.2 (C7a), 188.5 (C4)
21.5 (C6), 22.7 (C7), 38.1 (C5), 112.8 m (Cаrom), 117.1 (C3a), 120.0 q (CF3, 1J 270), 138.1 d.m (CаromF, 1J 255), 142.7 q (C3, 2J 40),
143.0 d.m (CаromF, 1J 261), 143.8 d.m (CаromF, 1J 257), 155.5 (C7a), 189.7 (C4)
21.5 (C6), 22.7 (C7), 38.1 (C5), 110.1 t. q (CF2, 1J 254, 2J 40), 112.7 m (Cаrom), 118.4 (C3a), 118.7 q (CF3, 1J 287, 2J 36), 138.1 d.m
(Cаrom, 1J 254), 141.9 t (C3, 2J 31), 143.0 d.m (CаromF, 1J 258), 143.7 d.m (CаromF, 1J 258), 154.8(C7a), 188.0 (C4)
21.5 (C6), 22.7 (C7), 38.1 (C5), 108.8 t. m (CF2, 1J 267), 112.5 t. t (CF2, 1J 256, 2J 32), 112.8 m (Cаrom), 117.9 q. t (CF3, 1J 288, 2J
34), 118.6 (C3a), 138.1 d.m (Cаrom, 1J 254), 141.8 t (C3, 2J 30), 143.1 d.m (CаromF, 1J 261), 143.7 d.m (CаromF, 1J 258), 154.9 (C7a),
188.9 (C4)
IIIj
IIIk
IIIl
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

SYNTHESIS AND SPECTROSCOPIC INVESTIGATION
1959
Table 4. (Contd.)
Comp.
no.
13С NMR spectrum (CDCl3), δ, ppm (JC–F, Hz)
28.3 (CH3), 34.9 (C6), 36.8 (C7), 53.7 (C5), 116.3 d (Cаrom, 2J 23), 117.8 (C3a), 119.0 q (CF3, 1J 272), 127.9 d (Cаrom, 3J 9), 130.8 q
(C3, 2J 41), 135.0 d (Cаrom), 156.5 (C7a), 163.1 d (CаromF, 1J 251), 191.6 (C4)
VIа
VIb
VIc
VId
VIe
VIf
VIg
VIh
VIi
1
2
2
1
2
28.2 (CH3), 34.7 (C6), 36.9 (C7), 53.9 (C5), 110.5 t.q (CF2, J 258, J 41), 116.0 d (Cаrom, J 23), 118.5 q. t (CF3, J 287, J 37),
119.0 (C3a), 128.9 d (Cаrom, 3J 9), 129.6 t (C3, 2J 31), 135.4 d (Cаrom), 156.8 (C7a), 162.3 d (CаromF, 1J 251), 190.8 (C4)
28.2 (CH3), 34.7 (C6), 36.9 (C7), 53.9 (C5), 108.6 t.m (CF2, 1J 266), 112.2 t. t (CF2, 1J 260, 2J 34), 116.7 d (Cаrom,2J 23), 117.6 q. t
(CF3, 1J 288, 2J 33), 119.3 (C3a), 129.0 d (Cаrom, 3J 9), 129.5 t (C3, 2J 31), 135.4 t (Cаrom), 156.8 (C7a), 163.2 d (CаromF, 1J 251), 190.9 (C4)
2
1
3
2
23.1 (C6,7), 39.8 (C5), 116.2 d (Cаrom, J 22), 118.8 (C3a), 119.0 q (CF3, J 272), 127.9 d (Cаrom, J 9), 131.0 q (C3, J 40), 135.1
(Cаrom), 157.4 (C7a), 163.1 d (CаromF, 1J 251), 191.9 (C4)
1
2
2
1
2
22.9 (C6), 23.2 (C7), 40.1 (C5), 110.0 t.q (CF2, J 259, J 41), 116.0 d (Cаrom, J 23), 118.5 q. t (CF3, J 287, J 38), 119.9 (C3a),
128.9 d (Cаrom, 3J 9), 129.8 t (C3, 2J 31), 135.5 d (Cаrom), 157.7 (C7a), 163.3 d (CаromF, 1J 251), 191.2 (C4)
22.9 (C6), 23.2 (C7), 40.1 (C5), 108.6 t.m (CF2, 1J 266), 112.2 t. t (CF2, 1J 257, 2J 34), 115.9 d (Cаrom, 2J 23), 117.7 q. t (CF3, 1J 288,
2J 34), 120.2 (C3a), 129.0 d (Cаrom, 3J 9), 129.7 t (C3, 2J 31), 135.5 t (Cаrom), 157.7 (C7a), 163.2 d (CаromF, 1J 251), 191.2 (C4)
28.3 (CH3), 34.9 (C6), 36.7 (C7), 53.5 (C5), 114.4 m (Cаrom), 118.4 (C3a), 118.5 q (CF3, J 272), 133.2 q (C3, J 42), 137.7 d. m
(CаromF, 1J 255), 143.1 d. m (CаromF, 1J 260), 143.8 d. m (CаromF, 1J 257), 154.4 (C7a), 189.3 (C4)
28.3 (CH3), 34.9 (C6), 36.7 (C7), 53.5 (C5), 109.7 t.q (CF2, 1J 258, 2J 41), 114.7 m (Cаrom), 118.3 q (CF3, 1J 287, 2J 37), 120.0 (C3a),
131.7 t (C3, 2J 31), 137.1 d. m (CаromF, 1J 254), 143.2 d. m (CаromF, 1J 261), 143.8 d. m (CаromF, 1J 256), 158.7 (C7a), 190.5 (C4)
28.1 (CH3), 34.7 (C6), 38.6 (C7), 53.8 (C5), 108.5 t.m (CF2, 1J 266), 111.9 t. t (CF2, 1J 260, 2J 34), 114.7 m (Cаrom), 117.5 q. t(CF3,
1J 288, 2J 34), 120.3 (C3a), 131.7 t (C3, 2J 31), 137.5 d. m (CаromF, 1J 253), 143.2 d. m (CаromF, 1J 260), 144.3 d. m (CаromF, 1J 256),
158.6 (C7a), 190.5 (C4)
1
2
22.8 (C6), 23.0 (C7), 39.7 (C5), 114.4 m (Cаrom), 118.5 q (CF3, 1J 272), 119.3 (C3a), 133.4 q (C3, 2J 42), 137.8 d. m (CаromF, 1J 255),
143.1 d. m (CаromF, 1J 260), 143.8 d. m (CаromF, 1J 257), 159.2 (C7a), 191.5 (C4)
22.6 (C6), 23.4 (C7), 40.2 (C5), 109.7 t.q (CF2, 1J 259, 2J 42), 114.7 m (Cаrom), 118.3 q (CF3, 1J 287, 2J 38), 120.9 (C3a), 131.9 t (C3,
2J 31), 137.5 d. m (CаromF, 1J 253), 143.2 d. m (CаromF, 1J 261), 144.2 d. m (CаromF, 1J 258), 159.4 (C7a), 190.7 (C4)
22.8 (C6), 23.0 (C7), 39.7 (C5), 108.6 t.m (CF2, 1J 266), 112.3 t. t (CF2, 1J 259, 2J 34), 114.8 m (Cаrom), 117.8 q. t (CF3, 1J 287, 2J
VIj
VIk
VIl
2
1
1
1
34), 121.4 (C3a), 132.0 t (C3, J 31), 137.6 d. m (CаromF, J 255), 143.5 d. m (CаromF, J 260), 144.6 d. m (CаromF, J 257), 159.7
(C7a), 190.9 (C4)
the signal of the carbonyl carbon atom (С4) and signals
of the carbon atoms of C–N (C7a) and C=N (C3) groups
are observed at 188.5–190.4, 150.6–155.0 and 139.5–
142.7 ppm respectively, while signals of the carbon
atoms С4 (C=O), С7a (C=N) and С3 (C–N) in the
isomeric indazolones VIа–VIl are observed at δ
190.5–191.9, 156.8–159.7 and 129.5–133.4 ppm
respectively. In the 19F spectra of compounds VIа–VIl
be used as a reliable method to determine structure of
the obtained regioisomeric indazolones. We carry out
15N–{1Н} НMВС experiments with compounds IIId
and VIe in order to establish the validity of structure
assigned to isomeric indazolones (Scheme 2).
19
Scheme 2.
as compared with compounds IIIа–IIIl the F signals
F
are shifted upfield. Thus trifluoromethyl-containing
6,7-dihydro-1H-indazol-4(5)H-ones III had the
fluorine atoms signals at δ –63.3– (–64.1) ppm, аnd
trifluoromethyl-containing 6,7-dihydro-2H-indazol-4(5)-
H-ones VI – at δ –56.4–(–59.7) ppm. In the mass-
spectra peaks of the molecular ion were observed for
the all compounds IIIа–IIIl and VIа–VIl.
We undertook additional studies for establishing
structure of the synthesized isomeric polyfluro-
alkylindazolones. The 15N spectroscopy method might
H
H
H
O
H
H
O
H
N
N
N
F
N
H
C2F5
CF3
IIId
VIe
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

1960
KHLEBNIKOVA et al.
The nitrogen atom bearing aromatic ring is easily
have substitution at the nitrogen atoms as indicated for
established from 2D spectra (Figs. 1, 2). The nitrogen
atom, which resonated at δ 314 ppm (N1) in compound
VIe (Fig. 1), has strong cross-peaks with the protons at
С7 and С6, less strong cross-peak with оrtho-protons
and very weak cross-signal with meta-protons of
aromatic ring. The second nitrogen atom (N2 at δ
217 ppm) gives other pattern. Here the strongest cross-
peaks with aromatic protons and weak peak of
interaction with protons at С7 were found. This signals
set observed obviously corresponds to the compound
compound VIe.
In the НMВС spectrum of the second analyzed
indazolone IIId two resonances of the nitrogen nuclei
are observed at δ 212 ppm for N1 and at δ 309 ppm for
N2, but with the completely distinctive set of cross-
peaks (Fig. 2). Here, contrary to compound VIe, the
nitrogen atom N1 interacts strongly with the aromatic
protons and with proton at C7. There is a weak cross-
peak with С6 in spectrum also. As to N2, only cross-
3.50
ppm (t2)
3.00
2.50
7.50
7.00
ppm (t2)
region of aliphatic protons
region of aromatic protons
Fig. 1. The 15N–{1Н} HMBC spectrum of compound VIe.
3.50
ppm (t2)
3.00
2.50
7.50
7.00
ppm (t2)
region of aliphatic protons
region of aromatic protons
Fig. 2. The 15N–{1Н} HMBC spectrum of compound IIId.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

SYNTHESIS AND SPECTROSCOPIC INVESTIGATION
1961
peak due to its weak interaction with proton at C7
(through 4 bonds) can be found. No plausible peaks
present in the range of aromatic protons for N2. Hence
it is evident that the nitrogen atom at the aromatic ring
is to be closer to С7 protons, than the second nitrogen
atom, since only in this case interaction through 3 and
4 bonds for protons of aromatic ring at С7 might be found.
perfluoroalkanoylcyclohexan-1,3-dione Iа-If in ethanol
(50 ml) was added 1.1 mmol of the fluorine-containing
phenylhydrazine (pentafluorophenylhydrazine or equi-
molar mixture of 4-fluorophenylhydrazine hydro-
chloride and sodium hydroxide). The reaction mixture
was stirred for 8 h at room temperature. Then ethanol
was removed on a rotary evaporator and residue was
dissolved in 50 ml of chloroform. The organic layer
was washed with 1:10 diluted hydrochloric acid (3×
15 ml) and water (2×15 ml) and was dried with
anhydrous magnesium sulfate. After solvent removal
on a rotary evaporator the residue was separated by the
preparative thin layer chromatography (ether:hexane
1:1) to obtain pure indazolones IIIа–IIIf, IIIj–IIIl as
orange crystals. Under the same conditions from
compounds of dimedone series Iа–Ic and pentafluoro-
phenylhydrazine the intermediate hydrazones IIg–IIi
were only obtained. The targeted indazolones IIIg–IIIi
were prepared at the reaction mixture refluxing in
ethanol during 10 h.
Therefore the data given above can be used to
confirm regiochemistry of the other obtained
indazolones.
As can be noted in conclusion, unlike acyclic
polyfluoroalkyl-containing β,β'-triketones and cyclic
β-diketones, reaction of 2-perfluoroalkanoylcyclo-
hexane-1,3-diones and their enol methyl esters with
phenylhydrazine proceeds regioselectively and allows
obtaining the new polyfluoroalkyl-containing 6,7-
dihydro-1H-indazol-4(5)H-ones III and 6,7-dihydro-
2H-indazol-4(5)H-ones VI respectively in preparative
yields.
5,5-Dimethyl-2-[2,2,2-trifluoro-1-(2-perfluoro-
phenylhydrazonoethyl)]cyclohexane-1,3-dione (IIg).
Yield 80%, yellow crystals, mp 169–172°С. IR
spectrum, ν, cm–1: 1570 (С=О conjug.), 1535 (С=С).
1Н NMR spectrum, CD3OD, δ, ppm: 1.14 m (6H,
2CH3), 2.33 m (2H, CH2), 2.55 m (2H, CH2). 13С NMR
spectrum, CD3OD, δ, ppm: 26.9 (CH3), 30.0 (CH3),
33.1 (C5), 47.8 (C4, C6), 104.2 (C2), 121.6 m (CAr),
122.7 q (CF3, 1JC–F 273 Hz), 134.9 q (CN, 2JC–F 36 Hz),
138.3 d.m (CArF, 1JC–F 247 Hz), 139.3 d.m (CArF, 1JC–F
EXPERIMENTAL
The NMR spectra were obtained on a Bruker
Avance-500 spectrometer in CDCl3 (unless otherwise
specified) using as internal reference TMS for 1Н (500
MHz) and 13С (125 MHz) and CCl3F for 19F (470
MHz). 15N NMR spectra were measured at 20°С on a
Bruker Avance-500 spectrometer (50.7 MHz) against
liquid ammonia as external reference (0 ppm). The
typical parameters of acquisition for HMBC
experiments are: relaxation delay 1.5 s; for F1 memory
size consisted 256, for F2 of 2048 bytes; spectral
1
244 Hz), 141.6 d.m (CArF, JC–F 248 Hz), 189.9 (C1,
19
C3). F NMR spectrum, CD3OD, δ, ppm: –68.5 s (3F,
1
CF3), –155.8 m (2F, CArF), –167.2 m (2F, CArF), –
diapason width 6.2 ppm for Н and 300 ppm for 15N,
1
evolution time was installed by calculation of nJ (N,Н) =
8 Hz. All of experimental data were obtained and
treated using program package XWIN-NMR 3.5.
167.8 t (1F, JC–F 21 Hz, CArF). GC–MS (70 eV), m/z
(rel. int.): 398 [M – H2O]+ (31). Found, %: C 46.25; H
2.96; N 6.79. C16H12F8N2O2. Calculated, %: C, 46.17;
H, 2.91; N, 6.73.
The IR spectra were recorded on a UR-20 device
(KBr). The mass spectra (EI, 70 eV) were obtained on
a Hewlett-Packard 5890 gas chromatograph with mass-
selective detector HP 5972. Melting points were
5,5-Dimethyl-2-[2,2,3,3,3-pentafluoro-1-(2-per-
fluorophenylhydrazonopropyl)]cyclohexane-1,3-di-
one (IIh). Yield 74%, yellow crystals, mp 143–146°С.
IR spectrum, ν, сm–1: 1590 (С=О conjug.), 1540
1
determined on a Boetius device. IR, mass, Н, 13С,
1
(С=С). Н NMR spectrum, δ, ppm: 1.12 s (3H, CH3),
19F NMR, and elemental analysis data are
presented in Tables 1–4. 2-Perfluoroalkanoylcyclo-
hexane-1,3-diones Iа-If were prepared in accordance
with technique [15, 16]. The reaction progress and
products purity were monitored by TLC (Silufol UV-
254, eluent ether).
1.14 s (3Н, СН3), 2.51 s (4H, 2CH2), 7.45 br.s (1Н,
13
NH), 8.71 br.s (1Н, NH). С NMR spectrum, δ, ppm:
27.3 (CH3), 28.3 (CH3), 32.5 (C5), 46.5 (C4, C6), 101.9
1
2
(C2), 111.0 t.q (CF2, JC–F 253 Hz, JC–F 37 Hz), 118.9
1
2
q.t (CF3, JC–F 287 Hz, JC–F 37 Hz), 119.3 m (CAr),
133.3 t (CN, JC–F 30 Hz), 136.6 d.m (CArF, JC–F
2
1
1
253 Hz), 138.0 d.m (CArF, JC–F 250 Hz), 138.6 d.m
1-Aryl-3-polyfluoroalkyl-6,7-dihydro-1Н-indazol-
4(5)Н-ones (IIIа-IIIl). To a solution of 1 mmol of 2-
(CArF, JC–F 248 Hz), 190.2 (C1, C3). 19F NMR
1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

1962
KHLEBNIKOVA et al.
spectrum, δ, ppm: –82.3 br.s (3F, CF3), –113.6 br.s
(2F, CF2), –156.2 m (2F, CArF), –163.4 m (2F, CArF), –
164.9 t (1F, 1JC–F 21 Hz, CArF). GC–MS, m/z (rel. int.):
448 [M – H2O]+ (30). Found, %: C 43.70; H 2.56; N
5.91. C17H12F10N2O2. Calculated, %: C 43.79; H 2.59;
N 6.01.
ACKNOWLEDGMENTS
This research was financially supported by the
Belarus Republic Foundation for Basic Research (grant
No. Х07M-022).
REFERENCES
5,5-Dimethyl-2-[2,2,3,3,4,4,4-heptafluoro-1-(2-per-
fluorophenylhydrazonobutyl]cyclohexane-1,3-dione
(IIi). Yield 78%, yellow crystals, mp 142–145оС. IR
spectrum, ν, cm–1: 1595 (С=О conjugated), 1540
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1
(С=С). Н NMR spectrum, δ, ppm: 1.11 s (3H, CH3),
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Ashmawey, I.M., Eur. J. Med. Chem., 2006, vol. 41,
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1.13 s (3Н, СН3), 2.51 s (4H, 2CH2), 7.46 br.s (1Н,
13
NH), 9.29 br.s (1Н, NH). С NMR spectrum, δ, ppm:
27.2 (CH3), 28.3 (CH3), 32.4 (C5), 46.5 (C4, C6), 102.3
(C2), 109.0 t.m (CF2, 1JC–F 266 Hz), 112.4 t.t (CF2, 1JC–F
256 Hz, 2JC–F 31 Hz), 118.3 q.t (CF3, 1JC–F 288 Hz, 2JC–F
3. Xu, W., Huang, L.-F., Bauer, L., Bhargava, H.N., and
Dunn, W.J., Bioorg. Med. Chem. Lett., 1999, vol. 9,
no. 23, p. 3375.
2
34 Hz), 119.3 m (CAr), 133.5 t (CN, JC–F 30 Hz,),
4. Lorand, T., Kocsis, B., Emody, L., and Sohar, P., Eur. J.
Med. Chem., 1999, vol. 34, no. 11, p. 1009.
136.6 d.m (CArF, 1JC–F 251 Hz), 138.1 d.m (CArF, 1JC–F
1
249 Hz), 138.7 d.m (CArF, JC–F 247 Hz), 190.2 (C1,
5. Kirsch, P., Modern Fluoroorganic Chemistry,
Weinheim: WILEY-VCH Verlag GmbH, 2004, p. 299.
C3). 19F NMR spectrum, δ, ppm: –80.5 t (3F, CF3, J
10 Hz), –111.0 br.d (2F, CF2), –125.6 br.s (2F, CF2), –
156.1 m (2F, CArF), –163.4 m (2F, CArF), –164.9 t (1F,
1JC–F 21 Hz, CArF). GC–MS, m/z (rel. int.): 498 [M –
H2O]+ (28). Found, %: C 41.76; H 3.91; N 6.85.
C18H12F12N2O2. Calculated, %: C 41.88; H 2.34; N
5.43.
6. Jeschke, P., Chem. Bio. Chem., 2004, vol. 5, no. 7, p. 571.
7. Furin, G.G., Khim. Geterotsykl. Soedin., 2006, no. 3.
p. 323.
8. Piccionello, A.P., Pace, A., Pibiri, I., Buscemi, S., and
Vivona, N., Tetrahedron, 2006, vol. 62, no. 37, p. 8792.
9. Pryadeina, M.V., Burgart, Ya.V., Kodess, M.I., Sa-
loutin, V.I., and Chupakhin, О.N., Izv. Akad. Nauk, Ser.
Khim., 2004, no. 6, p. 1210.
2-Aryl-3-perfluoroalkyl-6,7-dihydro-2Н-indazol-
4(5)Н-ones (VIа–VIl). To a solution of 1 mmol of 2-
perfluoroalkanoylcyclohexane-1,3-dione Iа-If in me-
thanol (10 ml) was added tetrabutylammonium
hydroxide solution in methanol (1.25 ml). The reaction
mixture was stirred during 1 h at room temperature and
absolute benzene (20 ml) was added. Then organic
solvents and water were removed by rotary evaporator.
To the obtained residue dissolved in 50 ml of benzene
was added 1.5 mmol of dimethylsulfate (0.15 ml).
After stirring for 24 h at room temperature 1 mmol of
fluorine-containing phenylhydrazine (pentafluorophenyl-
hydrazine or equimolar mixture of 4-fluoro-
phenylhydrazine hydrochloride and sodium carbonate)
was added. The reaction mixture was stirred during 5 h
at room temperature. The organic solution was washed
with the diluted hydrochloric acid 1:10 (3×20 ml) and
water (2×20 ml), and dried over anhydrous magnesium
sulfate. After solvent removal on a rotary evaporator
the residue was purified by preparative thin layer
chromatography on silica gel (ether:hexane 1:1) to
obtain pure indazolones VIа–VIl as orange crystals.
Physico-chemical and spectral data of compounds
VIа–VIl are given in Tables 2, 3, and 4.
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Ftorosoderzhashchie trikarbonil’nye soedinenia (Fluoro-
Containing Tricarbonyl Compounds), Yekaterinburg,
2002, p. 242.
14. Rubinov, D.B., Rubinova, I.L., and Akhrem, A.A.,
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16. Khlebnikova, T.S., Isakova, V.G., Baranovsky, A.V.,
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17. Аkhrem, А.А., Moiseenkov, A.M., Lakhvich, F.А., and
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SYNTHESIS AND SPECTROSCOPIC INVESTIGATION
1963
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008