Formation of polyfluorinated azobenzenes and azophenols in the reactions of chloropentafluoro-cyclohexa-2,5- and -2,4-dienones with phenyl- and pentafluorophenylhydrazines

Article abstract of DOI:10.1134/S1070428014010060

4-Chloropentafluorocyclohexa-2,5-dienone reacted with phenyl- and pentafluorophenylhydrazines in the presence of AlCl₃ via addition to the carbonyl group with formation of the corresponding azobenzenes. The reaction of 6-chloropentafluorocycloh

Full text of DOI:10.1134/S1070428014010060

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 1, pp. 29–34. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © V.N. Kovtonyuk, 2014, published in Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 1, pp. 37–42.
Formation of Polyfluorinated Azobenzenes
and Azophenols in the Reactions of Chloropentafluoro-
cyclohexa-2,5- and -2,4-dienones with Phenyl-
and Pentafluorophenylhydrazines
V. N. Kovtonyuk
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 9, Novosibirsk, 630090 Russia
e-mail: kovtonuk@nioch.nsc.ru
Received July 31, 2013
Abstract—4-Chloropentafluorocyclohexa-2,5-dienone reacted with phenyl- and pentafluorophenylhydrazines
in the presence of AlCl3 via addition to the carbonyl group with formation of the corresponding azobenzenes.
The reaction of 6-chloropentafluorocyclohexa-2,4-dienone with phenyl- and pentafluorophenylhydrazines both
in the presence and in the absence of AlCl3 afforded mainly 3-arylazotetrafluorophenols as products of nucleo-
philic replacement of fluorine atom at the double C=C bond.
DOI: 10.1134/S1070428014010060
1,2-Addition reactions of cyclohexadienones at the
carbonyl group are widely used in the synthesis of
various organic compounds, including analogs of
natural antibiotics [1]. The formation of azobenzenes
in reactions of cyclohexadienones with arylhydrazines
in the presence of acid catalysts is well known [2].
Carreño et al. [3] recently presumed that this reaction
involves arylhydrazine radical cations possessing
a high acidity and catalyzing reaction of arylhydra-
zines with dienones and quinone acetals; however, the
authors did not rule out the possibility for ceric am-
monium nitrate added to the reaction mixture to act not
only as oxidant but also as Lewis acid. It is known that
polyfluorinated cyclohexadienones are highly reactive
and versatile intermediate products for the synthesis of
various fluorine-containing organic compounds [4].
They are also capable of reacting via 1,2-addition to
the carbonyl group, in particular with 1,3-dipolar
(nitrile oxides, diazomethane) and organometallic
compounds [5, 6]. In addition, perfluoro(4-phenoxy-
cyclohexa-2,5-dienone) was found to react at the car-
bonyl group with AlCl3 complexes of pentafluoro-
phenyl- and phenylhydrazines with formation of
fluorinated azobenzenes [6]. Azobenzenes, including
those containing fluorine atoms, are used as dyes [7]
and photochromic materials for molecular electronics
[8]. Perfluorinated 2- and 4-phenylazophenols were
reported to inhibit androgen biosynthesis [9].
With a view to elucidate how the structure of poly-
fluorinated cyclohexadienones affects the formation
therefrom of fluorine-containing azobenzenes and azo-
phenols, the reactions of 4-chloropentafluorocyclo-
hexa-2,5-dienone and 6-chloropentafluorocyclohexa-
2,4-dienone with pentafluorophenyl- and phenylhydra-
zines, as well as with benzohydrazide, both in neutral
medium and in the presence of AlCl3 were studied in
the present work.
4-Chloropentafluorocyclohexa-2,5-dienone (I) re-
acted with excess aluminum trichloride–pentafluoro-
phenylhydrazine complex (C6F5NHNH2·AlCl3, II) to
afford mainly decafluoroazobenzene (III) and a small
amount of pentafluoroaniline (IV). Under analogous
conditions, the reaction of I with PhNHNH2·AlCl3 (V)
gave a mixture of pentafluoroazobenzene (VI), penta-
fluoroaniline (IV), pentafluorophenol (VII), and
a small amount of phenylazophenol VIII (Scheme 1).
Thus the formation of phenols VII and VIII in the
reaction of I with complex V is the main difference
from the reaction of the same substrate with complex
II. Phenol VIII is formed via nucleophilic replacement
of the 3-fluorine atom in initial dienone I, followed by
intramolecular redox transformation of fluorinated
3-phenylhydrazo-substituted dienone (cf. [6]). Penta-
fluorophenol (VII) is the product of reduction of
dienone I with phenylhydrazine or complex V.
29

KOVTONYUK
30
Scheme 1.
4C6F5NHNH2·AlCl3 (II)
5PhNHNH2·AlCl3 (V)
O
C6F5N=NC6F5
+
C6F5NH2
F
F
F
F
20°C
III
IV
OH
F
F
F
C6F5N=NPh
+
IV
+
C6F5OH +
F
Cl
I
N=NPh
F
VI
VII
VIII
hydrogen halide molecules from diastereoisomeric
adducts A according to the scheme proposed previ-
ously [4, 6] may be expected to involve equally
probable loss of fluorine and chlorine atoms from the
tetrahedral CFCl moiety. The fact that exclusive
elimination of the chlorine atom is observed in the
reaction of dienone I with complexes II and V may be
related to the consecutive formation of intermediate
hydrazone B and elimination of hydrogen chloride
from the latter (Scheme 2). Intermediate formation of
hydrazones in reactions of cyclohexadienones with
arylhydrazines under acidic conditions was presumed
in [2, 3], though such intermediates were not detected.
Pentafluoroaniline (IV) is one more compound
formed in appreciable amounts in both reactions. In the
reaction of I with V, the precursor of IV is likely to be
pentafluorohydrazobenzene C which decomposes into
aniline and pantafluoroaniline by the action of an acid
or complex V (Scheme 2). Presumably, pentafluoro-
hydrazobenzene C is generated by reduction of hydra-
zone B or pentafluoroazobenzene (VI) with phenylhy-
drazine. The yield of aniline IV did not decrease when
the ratio of phenylhydrazine and dienone I was
reduced by replacing excess complex V (which also
acts as a base) by the complex of 2-methylpyridine
with AlCl3. It is known that phenylhydrazine is capable
of reducing azo compounds and severing the nitrogen
atoms in hydrazobenzene derivatives [10]; dispropor-
tionation of polyfluorinated hydrazobenzenes by the
Analogous reactions of perfluoro(4-phenoxycyclo-
hexa-2,5-dienone) studied previously [6] also revealed
different behaviors of complexes II and V, related to
the possibility for elimination of either pentafluoro-
phenoxy group or fluorine atom from the tetrahedral
carbon atom. In the reaction with complex II, the
pentafluorophenoxy group is retained in the resulting
azobenzene, whereas the reaction with complex V
involves elimination of both pentafluorophenoxy
group and fluorine atom with equal probabilities. The
different behaviors of complexes II and V were
rationalized assuming π-electron interaction between
the aromatic substituent in the cyclohexadienone and
aromatic rings of arylhydrazines in the transition state
and synchronous cleavage of the primary addition
product of arylhydrazine to the carbonyl group of
cyclohexadienone [4, 6]. Azobenzenes can be formed
in the reaction of dienone I with complexes II and V
as a result of elimination of either fluorine or chlorine
atom as departing group. Elimination of the chlorine
atom yields azobenzenes III and VI, while no products
corresponding to elimination of the fluorine atom were
detected. In this reaction there are no factors that could
ensure diastereoselectivity in the primary addition of
arylhydrazine to the carbonyl group of cyclohexa-2,5-
dienone with formation of diene A (Scheme 2); the
same applies, e.g., to 1,3-dipolar cycloaddition of poly-
fluorinated cyclohexa-2,5-dienones to carbonyl com-
pounds [5]. Synchronous elimination of water and
Scheme 2.
O
NNHAr
HO
F
NHNHAr
F
F
F
F
F
F
F
F
F
F
ArNHNH2·AlCl3 (II, V)
C6F5N=NAr
–H2O
–HCl
F
F
F
Cl
Cl
F
Cl
I
A
B
III, VI
PhNHNH2
II, V
B or VI
C6F5NHNHAr
C6F5NH2
+
ArNH2
C
IV
Ar = C6F5, Ph.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

FORMATION OF POLYFLUORINATED AZOBENZENES AND AZOPHENOLS
31
action of acids or AlCl3 was also reported [11]. In the
reaction of dienone I with complex II, pentafluoro-
aniline (IV) may be formed via both reduction of deca-
fluoroazobenzene (III) and cleavage of pentafluoro-
phenylhydrazine by the action of acid.
The reaction of 6-chloropentafluorocyclohexa-2,4-
dienone (IX) with excess complex II resulted in the
formation of azophenol X and a small amount of deca-
fluoroazobenzene (III) (Scheme 3). In the reaction of
IX with complex V the major products were azophenol
VIII, 5-chlorotetrafluorophenol (XI), and pentafluoro-
phenol (VII); no pentafluoroazobenzene (VI) was
detected in the reaction mixture.
An essential difference between the reactions of IX
with complexes II and V is the formation of appre-
ciable amounts of phenols VII and XI in the latter
reaction. These products are likely to result from
reduction of dienone IX and probably 3,6-dichloro-
tetrafluorocyclohexa-2,4-dienone E with complex V.
Intermediate dichlorodienone E is the product of nu-
cleophilic substitution of the 3-fluorine atom in IX by
chlorine (Scheme 3). The formation of a small amount
of decafluoroazobenzene (III) (addition product to the
carbonyl group) in the reaction of IX with complex II
may be attributed to the presence of ~5–6% of dienone
I as an impurity in initial dienone IX.
Here, the main processes leading to azophenols
VIII and X are nucleophilic substitution of fluorine in
position 3 of dienone IX and subsequent intramolec-
ular redox transformation of fluorine-containing
3-arylhydrazocyclohexa-2,4-dienone D (Scheme 3).
Complexes II and V are likely to act as nucleophiles.
The reactions of IX with phenyl- and pentafluoro-
phenylhydrazines in the absence of AlCl3 afforded
azophenols VIII and X as the only products. They
were synthesized previously by reactions of perfluoro-
(4-phenoxycyclohexa-2,5-dienone) with phenyl- and
pentafluorophenylhydrazines [6]. Likewise, cyclo-
hexadienone IX reacted with benzohydrazide to
produce azophenol XII (Scheme 3).
Polyfluorinated cyclohexa-2,4-dienones are known
to be more reactive than isomeric cyclohexa-2,5-di-
enones in nucleophilic replacement of fluorine, the
most reactive being the 3-fluorine atom in the former
[4, 12, 13]. It may be expected that introduction of
another substituent into the 3-position of cyclohexa-
dienone IX should force the reaction with complex II
toward addition to the carbonyl group. The reaction of
cyclohexa-2,4-dienone IX with morpholine, followed
by treatment with both pentafluorophenylhydrazine
and complex II, led to the formation of azophenol XIII
as the major product (Scheme 4). Analogous treatment
of cyclohexa-2,5-dienone I first with morpholine and
then with complex II afforded morpholino-substituted
Scheme 3.
O
Cl
F
[AlCl4]–
PhNHNH2·AlCl3 (V)
F
Cl
F
F
E
O
N=NAr
OH
OH
Cl
ArNHNH2·AlCl3 (II, V)
20°C
F
F
F
F
F
F
F
F
F
F
F
F
+
+
+
C6F5OH
F
N=NAr
F
Cl
F
F
F
F
IX
III
VIII, X
XI
VII
O
F
OH
Cl
F
F
F
2RNHNH2
F
H
–HCl
N
R
N
F
F
N=NR
H
F
D
VIII, X, XII
VIII, R = Ph; X, R = C6F5; XII, R = COPh; Ar = C6F5, Ph.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

KOVTONYUK
32
Scheme 4.
O
O
OH
(1) Morpholine
(2) 4C6F5NHNH2·AlCl3
or 4C6F5NHNH2
Cl
Cl
F
F
F
F
F
F
F
–HCl
F
N
NHNHC6F5
N
N=NC6F5
F
O
F
O
F
IX
F
XIII
O
F
(1) Morpholine
(2) 5C6F5NHNH2·AlCl3
F
F
F
F
F
F
N
N=NC6F5
F
Cl
O
F
I
XIV
azobenzene XIV. The structure of phenol XIII implies
initial nucleophilic replacement of the 3-fluorine atom
in IX by morpholino group and of the 5-fluorine atom
by pentafluorophenylhydrazo group and subsequent
intramolecular redox transformation of dienone F
(Scheme 4).
was determined using a Knauer K-7000 osmometer.
The progress of reactions was monitored by TLC on
Merck 60 F254 plates. Silica gel (0.063–0.200 mm;
Merck) was used for column chromatography.
Polyfluorinated dienones I and IX were synthesized
following the procedures described in [12, 17].
19
According to the F NMR data, cyclohexadienone IX
EXPERIMENTAL
contained ~6–7% of pentafluorophenol (VII) and ~5–
6% of 4-chloropentafluorocyclohexa-2,5-dienone (I).
Aluminum chloride was purified by double vacuum
sublimation (20 mm). Diethyl ether was distilled over
solid sodium hydroxide.
Analytical and spectral studies were performed at
the Joint Chemical Service Center, Siberian Branch,
Russian Academy of Sciences.
1
The H NMR spectra were recorded from solutions
Bis(pentafluorophenyl)diazene (III). A solution of
0.79 g (4 mmol) of pentafluorophenylhydrazine in
10 mL of diethyl ether was cooled to 0°C, 0.53 g
(4 mmol) of finely powdered AlCl3 was added under
stirring, the mixture was stirred for 1–3 min, and
a solution of 0.22 g (1 mmol) of dienone I in 4 mL of
diethyl ether was added dropwise. The mixture was
stirred for 3 days at 20°C and treated with 50 mL of
~10% aqueous HCl and then with methylene chloride
(3×50 mL). The extract was dried over Na2SO4 and
evaporated, and the residue (0.71 g) was subjected to
column chromatography on silica gel using carbon
tetrachloride as eluent to isolate 0.31 g of a mixture of
products containing (GC/MS) ~74% of III, ~7% of
pentafluoroaniline (IV), and unidentified compounds.
Recrystallization from carbon tetrachloride gave 0.19 g
(53%) of III, with mp 138–141°C; published data [14]:
mp 143°C.
in carbon tetrachloride containing ~5% of acetone-d6
on a Bruker AV III 400 spectrometer (400.13 MHz);
the 19F NMR spectra were measured on a Bruker AV
300 instrument (282.36 MHz); the chemical shifts
were determined relative to acetone-d5 (δ 2.09 ppm
downfield from tetramethylsilane) and C6F6 (internal
reference). The 19F NMR spectra of compounds III,
VI, VIII, X, and XI completely coincided with those
given in [6, 14–16]. Gas chromatographic–mass spec-
trometric analysis was performed on a Hewlett
Packard HP 5890 Series II chromatograph coupled
with an HP 5971 mass-selective detector [HP-5MS
capillary column, 30 m×0.25 mm, film thickness
0.25 μm; carrier gas helium, flow rate 1 mL/min; oven
temperature programming from 50°C (2 min) to 280°C
at a rate of 10 deg/min and finally 5 min at 280°C;
injector temperature 280°C; ion source temperature
175°C; electron impact, 70 eV; 1.2 scan/s, a.m.u. range
30–650]. The elemental compositions of azophenol
XIII and azobenzene XIV were determined from the
high-resolution mass spectra (electron impact, 70 eV)
which were recorded on a DFS Thermo Scientific
instrument. The molecular weight of azophenol XII
1-(Pentafluorophenyl)-2-phenyldiazene (VI).
a. Likewise, from 0.54 g (5 mmol) of phenylhydrazine,
0.67 g (5 mmol) AlCl3, and 0.22 g (1 mmol) of dienone
I in 10 mL of diethyl ether (reaction time 20 h), 0.25 g
of a mixture of products was isolated. According to the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

FORMATION OF POLYFLUORINATED AZOBENZENES AND AZOPHENOLS
33
GC/MS data, it contained ~2% of initial dienone I,
~45% of VI, ~16% of IV, ~15% of VII, ~5% of VIII,
and unidentified compounds.
b. A solution of 0.22 g (1 mmol) of dienone IX in
15 mL of diethyl ether was added dropwise under
stirring to a solution of 0.40 g (2 mmol) of penta-
fluorophenylhydrazine in 8 mL of diethyl ether. The
mixture was stirred for 2 h, and the resulting solution
was passed through a column charged with silica gel.
The column was eluted with chloroform to isolate
0.35 g of orange crystals which were recrystallized
from carbon tetrachloride. Yield 0.29 g (80%),
mp 154–157°C; published data [6]: mp 155–158°C.
b. Finely powdered aluminum trichloride, 0.67 g
(5 mmol), was added under stirring to a solution of
0.22 g (2 mmol) of phenylhydrazine and 0.28 g
(3 mmol) of 2-methylpyrdine in 8 mL of diethyl ether,
cooled to 0°C, the mixture was stirred for ~3 min, and
a solution of 0.22 g (1 mmol) of dienone I in 4 mL of
diethyl ether was added dropwise. The mixture was
stirred for 5 days at 20°C and treated as described
above for the synthesis of III to isolate 0.27 g of
a mixture of products. According to the 19F NMR data,
the product mixture contained compounds I, VI, IV,
VII, and VIII at a ratio of 7:41:25:22:5 and 5–8% of
unidentified compounds.
N-[(2,4,5,6-Tetrafluoro-3-hydroxyphenyl)imino]-
benzamide (XII). Benzohydrazide, 0.27 g (2 mmol),
was added in portions under stirring to a solution of
0.22 g (1 mmol) of dienone IX in 10 mL of aceto-
nitrile. The mixture was stirred for 30 min, the precip-
itate was filtered off and washed with acetonitrile
(2×3 mL), the filtrate was combined with the washings
and evaporated, and the residue (0.31 g) was recrystal-
lized from acetonitrile. Yield 0.19 g (63%) mp 166–
168°C (decomp.). IR spectrum, ν, cm–1: 3298 br (OH),
1680, 1690 s (C=O), 1490–1530 s (several bands,
C6F4), 1450 m (N=N), 950–1040 s (several bands,
The product mixtures obtained as described in
a and b were combined and subjected to column
chromatography on silica gel using petroleum ether
(bp 70–100°C)–carbon tetrachloride (1:1) as eluent.
Compound VI was isolated as orange crystals, 0.26 g.
Recrystallization from carbon tetrachloride gave 0.17 g
(31%) of VI with mp 89–92°C; published data [15]:
mp 92–93°C.
1
C–F). H NMR spectrum, δ, ppm: 7.62 m (2H, m-H),
7.78 t (1H, p-H), 8.01 m (2H, o-H), 10.07 s (1H, OH).
19F NMR spectrum, δF, ppm: –2.1 t.d (1F, 5-F, J = 21,
7 Hz), 5.8 d.d (1F, 4-F, J = 21, 10 Hz), 15.4 d.d (1F,
6-F, J = 21, 11 Hz), 16.5 d.d.d (1F, 2-F, J = 11, 10,
7 Hz). Found, %: C 52.23; H 2.02; F 25.37; N 9.12.
M 310. C13H6F4N2O2. Calculated, %: C 52.36; H 2.03;
F 25.48; N 9.39. M 298.
2,4,5,6-Tetrafluoro-3-(phenyldiazenyl)phenol
(VIII). a. As described above for the synthesis of VI,
the reaction of 0.43 g (4 mmol) of phenylhydrazine
with 0.53 g (4 mmol) of AlCl3 and 0.22 g (1 mmol) of
dienone IX in 14 mL of diethyl ether (5 h) gave 0.31 g
of a mixture of products containing (GC/MS) ~6%
of I, ~25% of VIII, ~13% of XI, ~15% of VII, and
unidentified compounds.
2,4,6-Trifluoro-3-(morpholin-4-yl)-5-[(penta-
fluorophenyl)diazenyl]phenol (XIII). a. A solution of
0.09 g (1 mmol) of morpholine in 2 mL of diethyl
ether was added dropwise under stirring to a solution
of 0.22 g (1 mmol) of dienone IX in 5 mL of diethyl
ether. The mixture was stirred for 30 min and added
dropwise under stirring at 0°C to a solution of complex
II prepared from 0.79 g (4 mmol) of pentafluorophe-
nylhydrazine and 0.53 g (4 mmol) of finely powdered
AlCl3 in 10 mL of diethyl ether. The mixture was
stirred for 3.5 days at 20°C, treated with 80 mL of
~10% aqueous HCl, and extracted with methylene
chloride (3×50 mL). The extract was dried over
Na2SO4 and evaporated, and the residue (0.72 g) was
subjected to column chromatography on silica gel
using chloroform as eluent to isolate 0.34 g of XIII.
Double recrystallization from carbon tetrachloride
gave 0.25 g (58%) of XIII with mp 223–225°C
(decomp.). IR spectrum, ν, cm–1: 3150 br (OH), 2800–
3000 w (several bands, C–H), 1480–1522 s (several
bands, C6F3, C6F5), 1454 m (N=N), 980–1055 s
b. A solution of 0.22 g (1 mmol) of dienone IX was
added dropwise under stirring to a solution of 0.20 g
(2 mmol) of phenylhydrazine in 8 mL of diethyl ether.
The mixture was stirred for 2 h, and the resulting
solution was passed through a column charged with
silica gel. Elution with chloroform gave 0.20 g (74%)
of VIII with mp 131–133°C; published data [6]:
mp 130–133°C.
2,4,5,6-Tetrafluoro-3-[(pentafluorophenyl)di-
azenyl]phenol (X). a. As described above for the syn-
thesis of III, the reaction of 1.20 g (6 mmol) of penta-
fluorophenylhydrazine with 0.80 g (6 mmol) of AlCl3
and 0.22 g (1 mmol) of IX in 15 mL of diethyl ether
(6 h) gave 0.51 g of a mixture of products which
contained (19F NMR) compounds III, X, and VII and
pentafluorophenylhydrazine at a ratio of 9:71:4:16
together with 7–10% of unidentified compounds.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014

KOVTONYUK
34
1
1999, vol. 99, p. 1469; Sunasee, R. and Clive, D.L.J.,
J. Org. Chem., 2008, vol. 73, p. 8016; Broering, T.J. and
Morrow, G.W., Synth. Commun., 1999, vol. 29, p. 1135.
(several bands, C–F). H NMR spectrum, δ, ppm:
3.18 m (4H, CH2), 3.74 m (4H, CH2), 9.34 s (OH).
19F NMR spectrum, δF, ppm: 0.2 m (2F, m-F), 10.8 t
(1F, p-F), 12.4 m (2F, o-F), 16.1 d.d. (1F, 6-F, J = 13,
8 Hz), 23.3 d (1F, 4-F, J = 8 Hz), 30.7 d (1F, 2-F, J =
13 Hz). Found: m/z 427.0565 [M]+. C16H9F8N3O2. Cal-
culated: M 427.0562.
2. Taylor, E.C., Jagdmann, G.E., and McKillop, A., J. Org.
Chem., 1978, vol. 43, p. 4385; Bamberger, E. and
Reber, E., Ber., 1907, vol. 40, p. 2258; Hecker, E.,
Chem. Ber., 1959, vol. 92, p. 3198.
3. Carreño, M.C., Mudarra, G.F., Merino, E., and
b. A solution of 0.09 g (1 mmol) of morpholine in
3 mL of diethyl ether was added dropwise under
stirring to a solution of 0.22 g (1 mmol) of dienone IX
in 5 mL of diethyl ether. The mixture was stirred for
30 min, a solution of 0.80 g (4 mmol) of pentafluoro-
phenylhydrazine in 4 mL of diethyl ether was added,
and the mixture was stirred for ~4 days and evaporat-
ed. The residue was subjected to column chromatog-
raphy on silica gel using chloroform as eluent to
isolate 0.29 g of a compound identical to XIII in the
19F NMR spectrum.
Ribagorda, M., J. Org. Chem., 2004, vol. 69, p. 3413.
4. Kobrina, L.S., Izv. Akad. Nauk, Ser. Khim., 2002,
p. 1629.
5. Kovtonyuk, V.N., Kobrina, L.S., Kataeva, O.M., and
Haufe, G., Eur. J. Org. Chem., 2005, p. 1178; Kovto-
nyuk, V.N., Kobrina, L.S., and Gatilov, Yu.V., Russ. J.
Org. Chem., 2012, vol. 48, p. 783.
6. Kovtonyuk, V.N. and Kobrina, L.S., Izv. Akad. Nauk,
Ser. Khim., 1996, p. 1778.
7. Matsui, M., Funabiki, K., and Shibata, K., Bull. Chem.
Soc. Jpn., 2002, vol. 75, p. 531.
4-{2,4,5,6-Tetrafluoro-3-[(pentafluorophenyl)di-
azenyl]phenyl}morpholine (XIV). As described
above for the synthesis of XIII, the reaction of 0.22 g
(1 mmol) of dienone I with 0.09 g (1 mmol) of mor-
pholine, 1.00 g (5 mmol) of pentafluorophenylhydra-
zine, and 0.67 g (5 mmol) of AlCl3 in 22 mL of diethyl
ether (20 h) gave 0.56 g of a mixture of products con-
taining (19F NMR) compound XIV and pentafluoro-
aniline at a ratio of 68:32 and 10–14% of unidentified
compounds. The product mixture was subjected to
column chromatography on silica gel using carbon
tetrachloride–chloroform (1:1) as eluent to isolate
0.29 g of a viscous material. Double recrystallization
from hexane gave 0.18 g (42%) of XIV with mp 67–
8. Kawata, S. and Kawata, Y., Chem. Rev., 2000, vol. 100,
p. 1777; Feringa, B.L., van Delden, R.A., Koumura, N.,
and Geertsema, E.M., Chem. Rev., 2000, vol. 100,
p. 1789.
9. Jarman, M., Barrie, S.E., Deadman, J.J., Houghton, J.,
McCague, R., and Rowlands, M.G., J. Med. Chem.,
1990, vol. 33, p. 2452.
10. Ponzio, M., Gazz. Chim. Ital., 1914, vol. 441, p. 273;
Ritter, J.J. and Ritter, F.O., J. Am. Chem. Soc., 1930,
vol. 52, p. 2815.
11. Andreevskaya, O.I., Furin, G.G., and Yakobson, G.G.,
Zh. Org. Khim., 1977, 13, 1684; Petrova, T.D., Ryabi-
chev, A.G., Savchenko, T.I., Platonov, V.E., Mama-
tyuk, V.I., Gatilov, Yu.V., and Bagryanskaya, I.Yu.,
Zh. Org. Khim., 1986, vol. 22, p. 1297.
1
69°C. H NMR spectrum, δ, ppm: 3.23 m (4H, CH2),
12. Akhmetova, N.E., Kostina, N.G., and Shteingarts, V.D.,
Zh. Org. Khim., 1979, vol. 15, p. 2137.
13. Kovtonyuk, V.N., Kobrina, L.S., and Yakobson, G.G.,
3.76 m (4H, CH2). 19F NMR spectrum, δF, ppm:
–1.4 t.d (1F, 5-F, J = 21, 8 Hz), 0.1 m (2F, m-F), 11.3 t
(1F, p-F), 12.4 d.t (1F, 4-F, J = 20, 6 Hz), 12.7 m (2F,
o-F), 25.5 d.t (1F, 6-F, J = 21, ~6 Hz), 28.3 d.t (1F, 2-F,
J = 8, ~6 Hz). Found: m/z 429.0524 [M]+. C16H8F9N3O.
Calculated: M 429.0519.
Zh. Org. Khim., 1988, vol. 24, p. 1952.
14. Birchall, J.M., Haszeldine, R.N., and Kemp, J.E.G.,
J. Chem. Soc. C, 1970, p. 449.
15. Banks, R.E. and Prakash, A., J. Chem. Soc., Perkin
Trans. 1, 1974, p. 1365.
16. Akhmetova, N.E. and Shteingarts, V.D., Zh. Org. Khim.,
REFERENCES
1977, vol. 13, p. 1277.
1. Waring, A.J., Advances in Alicyclic Chemistry, Hart, H.
and Karabatsos, G.J., Eds., New York: Academic, 1966,
vol. 1, p. 129; Wipf, P. and Jung, J.-K., Chem. Rev.,
17. Banks, R.E. and Noakes, T.J., J. Chem. Soc., Perkin
Trans. 1, 1976, p. 143.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 1 2014