Organofluorine sulfur-containing compounds: V. Joint pyrolysis with chlorine or bromine of polyfluoroarenethioles, polyfluorohetarenethioles, and their derivatives

Article abstract of DOI:10.1007/s11178-006-0012-1

Joint pyrolysis with chlorine and bromine of polyfluoroarenethiols, -hetarenethiols, and their derivatives at 300-650°C furnished polyfluorocompounds containing chlorine and bromine. 2005 Pleiades Publishing, Inc.

Full text of DOI:10.1007/s11178-006-0012-1

Russian Journal of Organic Chemistry, Vol. 41, No. 11, 2005, pp. 1647-1653. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 11, 2005, pp.
1681-1687.
Original Russian Text Copyright Ó 2005 by Platonov, Maksimov, Dvornikova, Nikul’shin.
.
Dedicated to Professor H.-J Frohn (University of Duisburg, BRD)
on occasion of his 60th anniversary
Organofluorine Sulfur-containing Compounds: V.* Joint Pyrolysis
with Chlorine or Bromine of Polyfluoroarenethioles,
Polyfluorohetarenethioles, and Their Derivatives
V.E. Platonov, A.M. Maksimov, K.V. Dvornikova, and P.V. Nikul’shin
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, 630090 Russia
e-mail: platonov@nioch.nsc.ru
Received July 12, 2004
Abstract—Joint pyrolysis with chlorine and bromine of polyfluoroarenethiols, -hetarenethiols, and their derivatives
at 300-650°C furnished polyfluorocompounds containing chlorine and bromine.
The substitution of a hydrogen by bromine in 3H-
heptafluorotoluene was described performed in 60%
oleum to obtain 3-bromoheptafluorotoluene [15]. How-
ever the use of oleum as the medium may cause difficul-
ties in halogenation with the goal of replacing the hy-
drogen in the para-position in polyfluorobenzenes hav-
ing trifluoromethyl substituents since the latter exert a
destabilizing effect on the carbocation center [16, 17]
and are prone to hydrolysis under the action of oleum
[18, 19]. In turn at the use of the system Al+Br2 it is
presumable that the bromine would substitute the fluo-
rine atoms in the side chain as is the case in the reaction
of the octafluorotoluene with AlBr3 [17].
Polyfluoroarenes containing chlorine and bromine are
important material for preparation of versatile poyfluoro-
aromatic compounds with various functional groups [2].
At the same time only the simplest representatives of
chloro- and bromopolyfluoroarenes are relatively acces-
sible compounds (chloro- and bromopentafluorobenzenes,
dibromotetrafluorobenzenes).
It is known that chloropentafluorobenzene (I) (yield
20%) is obtained alongside the hexafluorobenzene (21%)
and polychlorofluorobenzenes from the hexachloroben-
zene by heating with potassium fluoride at 450-500°C
[3]. Recently the use of the phase-transfer catalysts was
suggested for reducing the process temperature [4]. In
reaction of the hexabromobenzene with the potassium
fluoride bromopentafluorobenzene (II) (yield 6%) formed
alongside the isomers of dibromotetrafluorobenz-ene (yield
8-9%) and tribromotrifluorobenzene (yield 4-5%) [5].
The replacement of hydrogen by chlorine in the penta-
fluorobenzene was studied effected by C12 [6], HC1, or
NaCl [7] in the presence of SbF5 or SbF5 complex with
sulfuryl chloride fluoride [8]. The reaction resulted in com-
pound I. The preparation of compound II was performed
by treating the pentafluorobenzene with bromine in 65%
[9] or 20% oleum in the presence of A1Br3 (yield 81%)
[10]. Under similar conditions the tetrafluorobenzenes
were brominated into dibromo derivatives (yield 38-78%)
[11, 12]. At the same time the attempt to chlorinate the
1,2,4,5-tetrafluorobenzene using SO2C12 in 65% oleum
was unsuccessful [13]. The preparation of 1,2,4-tribromo-
trifluorobenzene from 1,2,4-trifluorobenzene was perform-
ed by action of Br2 in the presence of aluminum [14].
* For communications IV, see [1].
Another approach to the synthesis of chloro- and
bromopolyfluoroarenes consisted in replacement of the
fluorine atom by chlorine or bromine in the hexafluoro-
benzene at its joint pyrolysis with C12 or Br2 or with
their sources at 650-740°C. The maximum yield of com-
pound I was 60%, and of compound II 27% [20]. Also a
substitution of iodine by chlorine or bromine was de-
scribed occurring at heating iodopentafluorobenzene with
C12 or Br2 at 120-150°C [21].
Taking into account the cited data we regarded as fea-
sible to study an opportunity of replacing by chlorine or
bromine other functional groups, in particular, thiol
groups which were introduced into polyfluoroarenes eas-
ily and relatively selectively by the nucleophilic substi-
tution [22].
It was formerly mentioned that a small amount of
4-chlorotetrafluoroacetanilide formed at threating with
chlorine 4-acetamidotetrafluorothiophenol in the glacial
acetic acid in the presence of water or hydrogen perox-
1070-4280/05/4111-1647Ó2005 Pleiades Publishing, Inc.

PLATONOV et al.
1648
Table 1. Joint pyrolysis of sulfur-containing polyfluoroarenes
and -hetarenes with C12
ide. The main reaction product was the corresponding
sulfochloride [23].
We demonstrated that at the joint pyrolysis of poly-
fluoroarenethiols with chlorine, its sources, or with bro-
mine in a flow system at 300-650°C the thiol group was
replaced by chlorine or bromine atoms furnishing the
corresponding haloderivatives of the polyfluoroarenes
(Tables 1 and 2, Scheme 1). As chlorine sources SO2C12
and SOC12 were applied (Table 3).
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This method makes it possible to obtain in an easy
way a wide range of various chloro- and bromopoly-
fluoroarenes. Therewith the process is characterized by
a high selectivity, and the yields of the target products in
reactions with chlorine (400°C) or bromine (500°C) reach
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process is of 96-99% purity. The high selectivity of the
process provides a possibility to synthesize isomer
compounds in individual state. It should be emphasized
that the use of C12 is preferred as opposed to SO2C12
and especially to SOC12 for in reactions with C12 the
products were obtained in higher yields and purity (cf.
data in Tables 1 and 3).
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The joint pyrolysis of pentafluorobenzenethiol (III)
with C12 or Br2 gave rise to compounds I and II respec-
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a Still residue. b According to the data of 19F NMR spectroscopy.
Table 3. Joint pyrolysis of polyfluorobenzenethiols with SO2C12
and SOC12
Table 2. Joint pyrolysis of sulfur-containing polyfluoroarenes and -
hetarenes with Br2
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b In the still residue (1.7 g) was identified disulfide IV (content 35%)
by comparing the 19F NMR spectrum with that of an authentic
sample.
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c The compound contains as impurity 0.8% of benzenethiol III.
d The product contained 0.9% of compound I. In the still residue
(1.7 g) was identified disulfide XXIII (content 30%) by comparing
the 19F NMR spectrum with that of an authentic sample. Same as
in case (b) the rest of the still residue contains presumably
compounds with two polyfluorinated benzene rings.
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b In the reaction product is present 0.9% of compound II.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

ORGANOFLUORINE SULFUR-CONTAINING COMPOUNDS: V.
1649
from compound V was observed previously in [24]. Com-
pound I was obtained in high yield from disulfide IV
and C12 at 405-410°C (Table 1, run no. 7).
Scheme 2.
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The maximum yield of compound II at the joint py-
rolysis of thiol III with Br2 is attained at higher tem-
perature (500°C) (Table 2, run no. 3) than in preparation
of compound I by reaction of thiol III with C12 (400°C).
The raising or reducing the reaction temperature of thiol
III with Br2 diminished the yield of the target product
(Table 2, runs nos. 2 and 4). At the decrease in the amount
of Br2 used in the process the yield of compound II also
decreases (Table 2, run no. 7). Compound II also forms
from disulfide IV and Br2 at 500°C (Table 2, run no. 11).
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R = H (III), SC6F5 (IV), Cl (V).
tively. Analogous transformations occurred under the
effect of C12 also with decafluorodiphenyl disulfide (IV)
and pentafluorobenzenesulfenyl chloride (V) (Tables 1
and 2, Scheme 2).
At decreasing the temperature of reaction between
thiol III and C12 to ~145°C (Table 1, run no. 4) sulfenyl
chloride V was obtained in a high yield with a small
impurity of compound I. Formerly sulfenyl chloride V
was obtained in reaction of C12 with thiol III and disul-
fide IV under mild conditions (-10 and 20°C respec-
tively) [24].
The joint pyrolysis of 2,3,5,6-tetrafluorothiophenol
(VI) with C12 or Bg2 cleanly afforded 1-chloro-2,3,5,6-
tetra-fluorobenzene (VII) and 1-bromo-2,3,5,6-
tetrafluoroben-zene (VIII) respectively. Therewith the
hydrogen in the ring virtually does not suffer replace-
ment by halogen atom (Scheme 4).
In reaction of thiol III with C12 at 290-3 00°C and
with reduced chlorine supply (III:C12 ~ 4:1) (Table 1,
run no. 5) the final reaction mixture contained unreacted
thiol III and disulfide IV in a molar ratio ~1:1 alongside
traces of compound I. Under similar conditions but at
the ratio of thiol III to C12 ~2:1 (Table 1, run no. 6) was
obtained additionally sulfenyl chloride V [molar ratio
(I):(V):(IV) ~ 1:4:17]. At further growing C12 supply
(III:C12 ~ 1:4) (Table 1, run no. 3) the resulting mixture
contains compound I as the main reaction product along-
side sulfenyl chloride V [(I):(V) ~ 5:3] (Scheme 3).
Similar processes occur with the other derivatives of
benzenethiol III containing in the para-position a chlo-
rine atom or a trifluoromethyl group. Thus were obtained
1,4-dichlorotetrafluorobenzene (XI), p-chloro- and
p-bromoheptafluorotoluenes (XII) and (XIII)
(Scheme 5).
The presence of a CF3 group in the ortho-position
with respect to SH does not hamper the substitution of
the latter by bromine (Scheme 6). In the same way from
5-nonafluoroindanethiol (XVIII) was obtained 5-bromo-
nonafluoroindane (XIX).
On pyrolysis (395°C) sulfenyl chloride V was con-
verted into compound I and disulfide IV, and also to a
lesser degree into decafluorodiphenyl sulfide and
decafluorodiphenyl trisulfide as revealed the GC-MS
analysis. The formation of compound I at 700-750°C(
10-13 Pa, 3.5 h) with quantitative elimination of sulfur
The joint pyrolysis of 4-tetrafluoropyridinethiol (XX)
with C12 or Br2 to form 4-chloro- (XXI) and 4-bromo-
tetrafluoropyridine (XXII) is an example of the same
Scheme 4.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

PLATONOV et al.
1650
Scheme 6.
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)
6+
)
)
)
%U
)
& ) &O
& ) 6&O
%U ꢀꢁꢅꢅ &
6&O
9
,
)
)
&)
;9,
)
&)
;9,,
$
)
ently an intermediate formation of a radical s-complex
A followed by elimination of the sulfur-containing func-
tion. The known example of conversion of decafluoro-
diphenyl disulfide at treatment with hydrogen bromide
into pentafluorobenzenesulfenyl bromide [27] may un-
derlie the suggestion of analogous conversion of
polyfluorodiaryl disulfides into polyfluoroarenesulfenyl
bromides effected by HBr under the conditions of joint
pyrolysis. Poly-fluoroarenesulfenyl bromides may also
arise alongside polyfluorodiaryl disulfides under the ac-
tion of bromine on the polyfluoroarenethiols.
)
)
)
)
)
)
)
%U
)
6+
)
%U ꢀꢁꢅꢅ &
)
)
)
)
)
)
)
;,;
;9,,,
Scheme 7.
6+
;
1
B
)
)
)
)
)
; ꢀꢁꢂꢂꢀꢀꢀꢃꢂꢂ &
Analogous schemes of replacement of the sulfur-con-
taining function by chlorine and bromine may be assumed
for conversions observed with the other polyfluoroarene-
thiols under the action of C12 or Br2. The processes where
chlorine sources are applied are apparently more com-
plex.
)
1
)
)
;;
;;,ꢀꢁ;;,,
The data cited above on the joint pyrolysis of thiol
III with C12 under various conditions make it possible
to suggest a scheme of compound I formation involving
primary conversion of thiol III under the action of C12
into sulfenyl chloride V. The latter then reacting with
C12 furnished compound I. In the presence of thiol III
sulfenyl chloride V can give disulfide IV [25] which
treated with C12 also is converted into compound I.
Therewith according to [23] it is presumable that disul-
fide IV with chlorine first transforms into sulfenyl chlo-
ride V. Thus the latter might be an intermediate on the
route to compound I from thiol III and disulfide IV
(Scheme 8). However the direct replacement of SH and
C6F5SS groups with chlorine in compounds III and IV
cannot be completely disregarded.
The substitution of RS groups by chlorine atom does
not contradict the data on the bond energy of the
C-X bonds for compounds C6H5X where X = SH
(355.5 kJ/mol), F (510.8 kJ/mol), C1 (396.9 kJ/mol),
H (457.6 kJ/mol), CF (448.8 kJ/mol) [28]. The weakest
bond is C—S. The comparison with the bond energy of
C-Br in C6H5Br (328.7 kJ/mol) is less obvious [28].
Presumably, in formation of polyfluorobromoarenes
is involved the substitution with bromine of groups BrS
(and alsoArF-SS) if it is possible to suggest the decreased
bond energy CAr-SX (X = Br, S-ArF) caused by X as
compared to the energy of the CAr-SH bond. For instance,
a trend to decreasing bond energy of CAr-S is observed
in going from benzenethiol to methylthiobenzene and to
diphenyl sulfide [28]. The methyldisulfide radical
(MeSS) was described as more resonance-stabilized than
Similar schemes were earlier suggested for formation
of RSC1 and RSSR from RSH and C12 [26]. The replace-
ment of the sulfur-containing function with chlorine and
bromine atoms at the high temperature involves appar-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

ORGANOFLUORINE SULFUR-CONTAINING COMPOUNDS: V.
1651
methylthiyl one (MeS), and also was mentioned the higher
reactivity of SH radical compared to that of SSH [29].
The synthesis of compound XIV is described in [30].
The other sulfur-containing compounds (IX, X, XVI,
XVIII, XX) were prepared as in [31].
EXPERIMENTAL
2,5-Bis(trifluoromethyl)-3,4,6-trifluoro-
1
benzenethiol (XVI). H NMR spectrum, d, ppm: 4.12
1
19F and H NMR spectra were registered on
quintet [J(H-F6) 8.5, J(H-2-CF ) 8.5 Hz]. 19F, d, ppm:
25.5 m (2F3,4), 55.2 d.d [F6, J(F6-5-CF ) 24, J(F6-H)
8.5 Hz], 105.1 t [5-CF , J(5-CF -F4) 24, J(5-CF -F6)
24 Hz], 105.3 d.d (2-CF , J(2-CF -F5) 28, J(2-CF -H)
8.5 Hz). Found: [M\+ 299.9646. C8HF9S. Calculated:
M299.9655.
spectrometer Bruker WP-200SY (at 188 and 200 MHz
respectively) from solutions in CCl4. The chemical
shifts are reported downfield from C6F6 and TMS;
internal references are C6F6 and HMDS (0.04 ppm
from TMS) respectively. IR spectra were recorded on
spectrophotometer Vector-22 from thin film or pellets
with KBr. Mass spectra were measured on Finnigan
MAT-8200 instrument, temperature at sample admission
70-110°C, nominal energy of ionizing electrons 70 eV; mass
spectra were used for evaluation of the precise molecular
mass and of the composition of compounds synthesized.
Joint pyrolysis of sulfur-containing arenes and
hetarenes with halogens and their sources. The process
was carried out in a quartz pipe (400 ´ 20 mm) heated in
an electric pipe oven. The initial compound was charged
into a dropping funnel (the compound was melted if
necessary) connected to the reactor. Before the
experiment the system was flushed with argon. The liquid
compounds were supplied simultaneously with the flow
of Cl2. The rate of the chlorine flow was ~44 g/h; the
duration of reagents input was mentioned in Table 1. In
experiments with chlorine sources and also with Br2 the
reagents were charged into the reactor from separate
dropping funnels in an argon flow (~5 l/h); in this case
the rate of polyfluoroarene (hetarene) input was 20-
25 g/h (Tables 2 and 3). On completion of initial
compound input into the reactor the supply of Cl2, Br2,
or SO2C12 and SOC12 was also finished. In some runs
of joint pyrolysis with chlorine the reaction products were
collected under a layer of ice water (Table 1, runs nos.
1,2, 7-12), then the collected mixture was warmed to
room temperature, separated, and subjected to steam
distillation. The distillate obtained was separated from
water, dried over CaC12, and analyzed by GLC, GC-MS,
and NMR methods. In other cases the products were
collected in a receiver cooled with liquid nitrogen (Table
1, run no. 3-6). Then the products were slowly defrosted
and analyzed by NMR spectroscopy.
GLC analysis was carried out on chromatographs
LKhM-72 and HP-5820 equipped with katharometer.
LKhM-72: columns 4000 ´ 4 mm, solid carrier Chromosorb
W, liquid stationary phases: silicone SKTFT-50, silicone
SKTFV-803, methylsilicone SE-30, and fluorosilicone QF-
1 (the ratio of liquid phase to solid carrier 15:100, oven
temperature 50-250°C, detector temperature 250°C,
helium flow rate 10 ml/min). HP-5820: column 30000´
0.5 mm coated with copolymer HP-5, oven temperature
40-280°C, detector temperature 280°C, helium flow rate
5 ml/min.
GC-MS procedure was performed on an instrument
equipped with a mass-selective detector HP G1801A.
Ionizing electrons energy was 70 eV. The separation
of compounds was performed on a column 30 m long
with the internal diameter of 0.25 mm, coated with a
film of copolymer HP-5 0.25 mm thick, carrier gashelium
at a flow rate 1 ml/min, oven temperature 50-280°C,
temperature of the ion source 173°C.
Benzenethiols III and VI. To a solution of 1 mol of
hexafluorobenzene or pentafluorobenzene in 1000 ml of
DMF was added at stirring within 7-10 min at room
temperature a solution of KSH prepared by passing
hydrogen sulfide through a solution of 2 mol of KOH in
350 ml of ethylene glycol till gain in weight of 64 g. At the
addition of the KSH solution the reactor was cooled
with water to maintain the temperature of the reaction
mixture below 45-55°C. Then the reaction mixture was
stirred for 4-5 h till it cooled to 25-28°C, and then it
was poured into 3000 ml of ~10% hydrochloric acid. The
organic layer was separated, dried over CaC12, and analyzed
by GLC. The reaction products were subjected to a vacuum
distillation at 12-14 mm Hg, yield 85-90%.
In the runs of the joint pyrolysis with bromine or the
chlorine sources the reaction products were collected in a
receiver cooled with ice water. Then the reaction mixture
was warmed to room temperature and subjected to steam
distillation. In the experiments with bromine the reaction
mixture was preliminary treated with a solution of sodium
sulfite to remove the excess bromine. After distillation the
distillate obtained was separated from water, dried with
CaC12, and analyzed by GLC and NMR methods.
The results of joint pyrolysis are presented in
Tables 1-3.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

PLATONOV et al.
1652
Br 22.82, 22.90; F 49.08, 49.32. [MJ 345.9048. C8BrF9.
Calculated, %: C 27.67; Br 23.05; F49.28. M345.9040.
The formation of compounds I, IV, and V was confirmed
by 19F NMR spectra, by GC-MS data, and by comparison
with the published data on chemical shifts and coupling
constants in the 19F NMR spectra [25, 32].
5-Bromononafluoroindane (XIX). 19F NMR
spectrum, d, ppm: 23.1 d.d.t [F7, J(F7-F ) 21, J(F7-F4)
19, J(F7-1-CF2) 7 Hz], 32.1 quintet [F , J(F -1,3-CF2) 4
Hz], 48.9 d, components broadened [F , J(F -F7) 21
Hz], 54.0 d.t.d [F4, J(F4-F7) 19, J(F4-3-CF2) 7, J(F4-F ) 5
Hz], 54.6 br.s [1(3)-CF2], 55.0 br.s [1(3)-CF2] [38].
1-Chloro-2,3,5,6-tetrafluorobenzene (VII). IR
spectrum, cm-1: 715, 846, 920, 937, 1136, 1178, 1248,
1455, 1515, 1635, 3093.1H NMR spectrum, d, ppm:
7.05 t.t [J(H-F3,5) 9.9, J(H-F2,6) 7.2 Hz]. 19F NMR
2,6
spectrum, d, ppm: 21.7 m (F ), 24.9 m (F3,5) [33]. Found
4-Chlorotetrafluoropyridine (XXI). IR spectrum,
cm-1: 579, 698, 915, 956, 1241, 1474, 1498, 1633. 19F
NMR spectrum, d, ppm: 21.0 m (F3), 74.0 m (F ) [39].
Found [M] 184.9653. C5C1F4N. Calculated M 184.9655.
[M\ 183.9708. C6HC1F4. Calculated M l83.9703.
1-Bromo-2,3,5,6-tetrafluorobenzene (VIII). IR
spectrum, cm-1: 699, 847, 863, 913, 929, 1132, 1176,
1237, 1445, 1501, 1626, 3085. 1H NMR spectrum, d,
ppm: 7.10 t.t [J(H-F3,5) 9.5, J(H-F2,6) 7.0 Hz]. 19F NMR
spectrum, d, ppm: 24.8 m (F3,5), 29.1 m (F2,6). Found
[M] 227.9205. C6HBrF4. Calculated M 227.9198.
4-Bromotetrafluoropyridine (XXII). IR spec-
trum, cm-1: 565, 697, 864, 950, 1232, 1463, 1481,
1622. 19F NMR spectrum, d, ppm: 27.6 m (F3 ) 74.4 m (F
). Found [MJ 228.9146. C5BrF4N. Calculated M228.9150.
1,4-Dichlorotetrafluorobenzene (XI). mp 48.5-51°C
(publ.: mp 50.5-51.5°C [34]). 19F NMR spectrum, d,
ppm:22.4 s [35].
2,2',3,3',5,5',6,6'-Octafluorodiphenyl disulfide
(XXIII). 1H NMR spectrum, d, ppm: 7.15 t.t [J(H-F3)
9.2, J(H-F2,6) 7.2 Hz] [40]. 19F NMR spectrum, d, ppm:
25.0 m (F3), 29.5 m (F ).
4-Chloroheptafluorotoluene (XII). IR spectrum,
cm-1: 717, 845, 988, 1156, 1188, 1334, 1496, 1646. 19F NMR
spectrum, d, ppm: 23.4 m (F2,6), 24.1 m (F3,5), 106.6 t
[CF , J(F5-Fa) 22 Hz] (av. 22.6, 23.7, and 105.3 respectively
[36]). Found [M] 251.9600. C7C1F7. Calculated M 251.9577.
4-Bromoheptafluorotoluene (XIII). IR spectrum, cm-
1:716, 818, 984, 1155, 1183, 1331, 1499, 1645. 19F NMR
spectrum, d, ppm: 23.1 m (F2,6), 31,7 m (F3,5), 105.5 t
[CF, J(F5-Fa) 22 Hz] [37]. Found [M] 295.9096. C7BrF7.
Calculated M 295.9072.
Thermolysis of sulfenyl chloride (V) was carried
out in a quartz pipe (400 ´ 20 mm) heated in an electric
pipe oven. From a dropping funnel was uniformly
supplied into the reactor 30.1 mmol of compound V
within 11 min in an argon flow (5-6 l/h) at ~395°C. We
obtained 6.4 g of reaction products that according to
NMR spectra contained no initial compound V. From
5.8 g of the crude product by steam distillation we
obtained 3.4 g of a mixture containing according GC-
MS data 66.7% of compound I, 27.9% of disulfide IV,
and also 2.0% of decafluorodiphenyl sulfide, and 0.3%
of decafluorodi-phenyl trisulfide. The estimated percent
content of compounds I and IV in this mixture is
consistent with the 19F NMR spectrum. The composition
of the still residue was not analyzed.
1-Bromo-2,4-bis(trifluoromethyl)-3,5,6-trifluoro-
benzene (XV). IR spectrum, cm-1: 870, 946, 1165, 1200,
1240, 1340, 1370, 1455, 1490, 1610, 1635. 19F NMR
spectrum, d, ppm: 37.1 quintet, all lines broadened (F5),
37.9 d.d [F6, J(F6-F5) 22, J(F6-F5) 12.5 Hz], 49.8
q.q.d.d [F5, J(F5-2-CF ) 34.5, J(F5-4-CF ) 23, J(F5-F6)
12.5, J(F5-F5) 1.5 Hz], 105.5 d.d [4-CF , J(4-CF –F3)
24, J(4-CF -F5) 23 Hz], 105.9 d [2-CF, J(2-CF -F5)
34.5 Hz]. Found, %: C 27.54, 27.72; Br 22.60, 22.90; F
48.86, 49.18. [M] 345.9038. C8BrF9 . Calculated, %:
C 27.67; Br 23.05; F 49.28. M 345.9040.
The study was carried out under financial support
of the Presidium of the Russian Academy of Sciences
(IP ¹ 9.4).
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 11 2005