Synthesis and properties of fluorinated 2-benzoylcyclohexane-1,3-diones

Article abstract of DOI:10.1134/S1070363207100118

Fluorinated 2-benzoylcyclohexane-1,3-diones were obtained by the O-C isomerization of the corresponding 3-benzoyloxycyclohex-2-en-1-ones under the action of acetone cyanohydrin in the presence of triethylamine in the medium of absolute acetonitrile. The s

Full text of DOI:10.1134/S1070363207100118

ISSN 1070-3632, Russian Journal of General Chemistry, 2007, Vol. 77, No. 10, pp. 1724 1731.
Original Russian Text T.S. Khlebnikova, V.G. Isakova, A.V. Baranovskii, F.A. Lakhvich, A.S. Lyakhov, 2007, published in Zhurnal Obshchei Khimii,
2007, Vol. 77, No. 10, pp. 1657 1664.
Pleiades Publishing, Ltd., 2007.
Synthesis and Properties
of Fluorinated 2-Benzoylcyclohexane-1,3-diones
T. S. Khlebnikovaa, V. G. Isakova,a A. V. Baranovskiia,
F. A. Lakhvicha, and A. S. Lyakhovb
a Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus,
ul. Akad. Kuprievicha 5/2, Minsk, 22014 Belarus
e-mail: khlebnikova@iboch.bas-net
b Research Institute of Physicochemical Problems, Belarus State University, Minsk, Belarus
Received June 5, 2007
Abstract Fluorinated 2-benzoylcyclohexane-1,3-diones were obtained by the O C isomerization of the
corresponding 3-benzoyloxycyclohex-2-en-1-ones under the action of acetone cyanohydrin in the presence of
triethylamine in the medium of absolute acetonitrile. The structure of the target compounds was investigated
by the means of IR and NMR spectroscopy, and X-ray diffraction analysis.
DOI: 10.1134/S1070363207100118
Widespread natural cyclic
, -triketones of
as effective herbicides, such as mesotrione and salco-
trione, and others [8 10]. 2-[2-Nitro-4-(trifluorome-
thyl)benzoyl]cyclohexane-1,3-dione (NTBC) is suc-
cessfully applied in the therapy of tyrosinemia type I
[11]. One of the possible mechanisms of action of
these compounds, both as herbicides and medicines,
is inhibition of 4-hydroxyphenylpyruvate dioxygenase
by chelating the iron(II) ion of this enzyme with the
enol form of , -triketones [12, 13].
various structures, possessing various types of bio-
logical activity, constitute an interesting class of
polyfunctional compounds [1, 2]. 2-Acylcycloalkane-
1,3-diones both of the cyclohexane and cyclopentane
series are widely used in the synthesis of biologically
active compounds due to the rich synthetic potential
of the polyfunctional , -tricarbonyl system [3 7].
Presently various 2-benzoylcyclohexane-1,3-diones
and other cyclic , -triketones are used in agriculture
Scheme 1.
Cl
NO2
O
NO2
O
O
O
O
O
CF3
SO2Me
O
O
SO2Me
O
Mesotrione
Salcotrione
NTBC
Recently, based on the nitrile oxide synthetic ap-
proach to 2-benzoylcyclohexane-1,3-diones [14, 15],
Akhrem et al. [16] performed effective synthesis of
coleophomones isolated from two species of fungi,
whose biological profile includes fungicide and anti-
biotic activity and myocardial chimase inhibition.
primarily in the production of medicines and pesticides
[17, 18]. This is connected with the fact that fluorine
and its compounds can, for example, enhance ef-
ficiency and selectivity of medicines [19]. It is known
that introduction of fluorine and fluorinated substi-
tuents in the molecule of a biologically active com-
pound can alter the physicochemical and biological
properties of the latter.
The goal of the present work was to obtain new
fluorinated
2-benzolcyclohexane-1,3-diones
and
investigate their structure.
There are a number of synthetic approaches to
cyclic , -triketones [20]. Among the most effective
methods of synthesis of 2-acylcyclohexane-1,3-diones
It is important to note that fluorinated compounds
have gained extensive application in organic synthesis,
1724

SYNTHESIS AND PROPERTIES OF FLUORINATED 2-BENZOYLCYCLOHEXANE-1,3-DIONES
1725
is O C isomerization of cyclohexane-1,3-dione enol
acylates under the action of some catalysts, such as
aluminum chloride, N,N-dimethylaminopyridine, zinc
chloride, and others. Attempted synthesis of fluori-
nated 2-benzoylcyclohexane-1,3-diones Ia Ie by iso-
merization of 3-benzoyloxycyclohex-2-en-1-ones IIa
IIe in boiling absolute toluene in the presence of di-
methylaminopyridine or zinc chloride under the condi-
tions described in [21] were unsuccessful. Thus, acyla-
tion of 5,5-dimethylcyclohexane-1,3-dione with fluoro-
benzoic acids in the presence of 1,3-dicyclohexylcar-
bodiimide, triethylamine, and dimethylaminopyridine
in chloroform by the procedure described in [22]
resulted in isolation of enol acylates IIa IIe only. It
was reported [23, 24] that isomerization of 3-benzoyl-
cyclohex-2-en-1-ones containing fluorine in the ortho
position of the benzene ring, in the presence of alu-
minum chloride in dichloroethane or in the presence
of KCN and triethylamine in methylene chloride led
to intramolecular nucleophilic heterocyclization of the
, -triketones formed with HF liberation and forma-
tion of 2,3,4,9,-tetrahydro-1H-xanten-1,9-diones.
We found that the O C isomerization of fluorinated
enol acylates IIa IIe into the corresponding 2-benzoyl-
cyclohexane-1,3-diones Ia Ie proceeds under the ac-
tion of catalytic amounts of acetone cyanohydrin in
the presence of triethylamine in absolute acetonitrile
[25, 26]. The yields of the target products were 72
93%. Under these conditions, no intramolecular hetero-
cyclization of 2-(2-fluorobenzoyl)-5,5-dimethylcyclo-
hexane-1,3-dione (Ia) and 2-(2,3,4,5,6-pentafluoro-
benzoyl)-5,5-dimethylcyclohexane-1,3-dione (Ie) was
observed.
Scheme 2.
O
X
O
O
O
X
O
Cl
Me
Me
OH
CN
O
X
Py, CHCl3
O
O
Et3N, MeCN
O
IIa IIe
Ia Ie
I, II, X = 2-F (a), 3-F (b), 4-F (c), 4-CF3 (d), 2,3,4,5,6-F (e).
Enol derivatives IIa IIe were prepared by a routine
procedure via O-acylation of 5,5-dimethylcyclohexane-
1,3-dione with fluorobenzoyl chlorides in the presence
of an equivalent amount of pyridine in absolute chloro-
form in 73 95% yields [27].
formation of exo/endo-enol tautomers differing from
each other by the positions of the conjugated carbonyl
group and conjugated chelate system with a strong
intramolecular bond [28].
According to the spectral data, fluorinated 2-ben-
zoylcyclohexane-1,3-diones Ia Ie are completely
enolized, like other cyclic , -triketones [29, 30]. The
IR spectra of compounds Ia Ie contain an absorption
band of the conjugated carbonyl group (1675
The structure of compounds Ia Ie and IIa IIe was
1
confirmed by IR, H, 13C, and 19F NMR spectroscopy
and elemental analysis. Parameters of known com-
pounds were compared with published data. Thus, the
IR spectra of enol acylates IIa IIe show characteristic
absorption bands of the ester carbonyl group (1740
1
1700 cm ) and a broad absorption band in the range
1
1770 cm ), conjugated carbonyl group (1670
H
1
1
1680 cm ), and double bond (1600 1620 cm ). The
1H NMR spectra of these compounds contain, along
with methyl, methylene, and aromatic proton signals,
a vinyl proton signal as a broad triplet at 6 ppm
(J 1 Hz) and a methylene proton signal as a broadened
doublet (J 1 Hz) at 2.6 ppm. For complete assign-
H
H
H
H
H
H
O
H
1
H
H
H
ment of signals of enol acylates Ia Ie in the H and
H
13C NMR spectra, we measured the HMBC spectrum
of 3-(2-fluorobenzoyloxy)-5,5-dimethylcyclohex-2-en-
1-one (IIa).
O
H
H
O
F
H
The presence of the -tricarbonyl group in com-
pounds Ia Ie suggests keto enol equilibrium and
Fig. 1. Principal correlations in the HMBC spectrum of
enol acylate IIa.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 10 2007

1726
KHLEBNIKOVA et al.
Table 1. 13C NMR parameters of compounds Ia Ie, , ppm (JC F, Hz)a
Atom
PhCO
Ia
Ib
Ic
Id
Ie
194.86
193.95
113.82
194.75
45.88
31.00
51.71
28.24
197.34
194.01
112.39
195.62
46.09
31.20
52.24
28.43
197.06
194.21
112.26
195.60
46.19
31.13
52.36
28.42
197.54
193.89
112.25
196.05
46.06
31.09
51.10
28.30
187.07
194.13
113.19
196.00
44.96
31.21
51.07
28.08
C1
C2
C3
C4
C5
C6
CH3
C1
C2
C3
127.55 d (2J 14) 140.35 d (3J 7) 134.22 d (4J 3)
159.33 d (1J 250) 115.26 d (2J 23) 131.22 d (3J 10)
115.32 d (2J 22) 162.15 d (1J 246) 114.99 d (2J 22)
141.62
128.21
124.80
114.80 t.d (2J 38, 3J 4)
142.22 d.m (1J 256)
137.41 d.t.d (1J 254,
2J 14, 3J 5)
C4
C5
132.77 d (3J 9)
124.15 d (4J 3)
118.69 d (2J 22) 165.11 d (1J 253) 132.89 q (2J 33) 143.24 d.m (1J 250)
129.48 d (3J 8) 114.99 d (2J 22)
124.80
137.41 d.t.d (1J 254,
2J 14, 3J 5)
C6
PhCF3
128.94 d (5J 2)
123.97 d (4J 3) 131.22 d (3J 10)
128.21
142.22 d.m (1J 256)
123.75 q (1J 273)
a
The spectra of compounds Ia and Ie were recorded at 40 C, and the other, at room temperature.
1
of 1555 1585 cm due to the carbonyl group intra-
molecularly hydrogen-bonded with the enol hydroxyl).
J 250 Hz). Further evidence for the presence of fluo-
rine atoms bonded to the aromatic ring in compounds
Ia Ie is provided by the occurrence of corresponding
signals in the 19F NMR spectra. The 13C NMR spectra
of compounds Ia Ie contain three signals from the
exo- and endocyclic carbonyl groups in the region of
1
The H NMR spectra of compounds Ia Ie display a
downfield enol proton signal at 16.8 16.9 ppm. The
presence of fluorine atoms bonded to the aromatic
ring in compounds Ia Ie is confirmed by the observa-
tion in the 13C NMR spectra (Table 1) of a doublet
signal at 160 165 ppm (J 246 253 Hz). In the 13C
NMR spectrum of compound IId containing the CF3
186 197 ppm.
C
To reveal the enolization direction and assign sig-
1
nals in the H and 13C NMR spectra, we measured the
group, a quartet carbon signal is observed at
C
HMBC spectra of fluorinated 2-benzoylcyclohexane-
1,3-diones Ia Ie.
123.75 ppm (J 273 Hz). The 13C NMR spectrum of
compound IIe displays three doublets of multiplets
due to carbon atoms of the pentafluorinated benzene
ring at C, ppm: 137.41 d.d (C3 , C5 , J 254; 15 Hz),
In the all the cases, a similar coupling pattern was
observed: The protons at C6 and C4 had cross-peaks
with C1 and C3, respectively. The enol proton gave
142.22 d.m (C2 , C6 , J 257 Hz), and 143.22 d.m (C4 ,
Scheme 3.
H
H
H
H
O
O
H
X
H
H
3
6
2
5
4
5
2
1
H
1
6
3
4
F
H
O
H
H
O
Ia Ie
H
H
O
H
O
O
OH
O
O
X
X
3
O
H
2
1
O
Fig. 2. Principal correlations in the HMBC spectrum of
, -triketone Ic.
exo
endo
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 10 2007

SYNTHESIS AND PROPERTIES OF FLUORINATED 2-BENZOYLCYCLOHEXANE-1,3-DIONES
C14
1727
C15
C5
C6
C13
C12
O1
C2
F11
C1
C11
C10
C7
C4
C3
C8
C9
O3
O7
Fig. 3. Structure of molecule Ic. The dashed line shows the intramolecular hydrogen bond.
cross-peaks with C2, C3, and C4. Coupling of the
exocyclic carbonyl carbon with the ortho proton of
the aromatic ring was observed in the spectra of all
the compounds, except for compound Ie which has no
ortho proton. The above evidence led us to conclude
that the enolized endocyclic carbonyl in compounds
Ia Ie resonates downfield from nonenolized. The
same picture was observed with other our synthesized
fluorinated , -triketones [31]. To obtain further
evidence for our assignments, we recorded low-
temperature 13C NMR spectra with deuterium ex-
change for compounds Ia, Id, and Ie. In all the cases,
the largest upfield shift upon addition of heavy water
was detected for C3, in complete agreement with the
HMBC results. The deuterium-induced shifts of sig-
nals in the 13C NMR spectra are listed in Table 2 (a
negative sign means an upfield shift and a positive,
a downfield shift).
involved into a strong intramolecular hydrogen bond
O3 H3 O7 (Table 3) which can be referred to as a
resonance-assisted hydrogen bond [33].
The structure also includes C H O intermolecular
hydrogen bonds which cause dimer formation (Fig. 4).
It should be noted that compound Ic belongs to the
same structural type as 2-benzoyldimedone we studied
earlier [34]. The crystallographic data and parameters
of the least-squares refinement (MLS) for structure Ic
are presented in Table 4, and the atomic coordinates
and equivalent thermal parameters are given in
Table 5.
Table 2. Isotopic chemical shifts of signals (ppm) in the
13C NMR spectra of compounds Ia, Ic, and Ie
Atom
Ia
Ic
Ie
The structure of fluorinated 2-benzoylcyclohexane-
1,3-diones Ia Ie was single-crystal X-ray diffraction
data for compound Ic. Figure 3 shows the molecular
structure of Ic which is evidently the endo-enol
tautomer.
C1
0.3
0.10
1.8
0.11
0.16
1.9
0.05
0.04
1.3
0.33
0.05
0.22
C2
C3
C4
0.5
0.5
C6
0.08
0.13
0.4
0.12
0.16
0.4
COPh
The bonds length and angles in this molecule are
normal values [32]. The hydroxyl hydrogen atom is
C1
Table 3. Parameters of hydrogen bonds in the crystal of compound Ic ( , deg)
D H A
d(D H)
d(H A)
d(D A)
(D H A)
O3 H3 O7
1.07(2)
0.976(19)
1.45(2)
2.586(19)
2.4572(15)
3.558(2)
153.7(17)
174.0(15)
a
C12 H12 O1#1
a
Symmetry code: (#1) x, 1
y, z.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 10 2007

1728
KHLEBNIKOVA et al.
C12
O1
O1
C12
Fig. 4. Dimer in the crystal structure of compound Ic. The dashed line shows hydrogen bonds.
Table 4. Crystallographic data and MLS refinement
parameters for structure Ic
EXPERIMENTAL
The NMR spectra were recorded on a Bruker
Avance-500 spectrometer operating at 500 MHz (1H)
and 125 MHz (13C) in CDCl3 against internal TMS.
The 19F NMR spectra were measured at 470 MHz
against CCl3F. The IR spectra were obtained on a UR-
20 spectrometer from KBr pellets. The melting points
were measured on a Boetius hot stage. The reaction
progress and purity of compounds were monitored by
TLC on Silufol UV-254 plates, eluent ether. The 13C
NMR spectra of compounds Ia Ie are presented in
Table 1.
Formula
Molecular weight
,
Syngony
Space group
Unit cell parameters
a,
C15H15FO3
262.27
0.71073
Monoclinic
P21/n
7.3360 (13)
15.139 (3)
11.932 (3)
101.526 (16)
1298.4 (5)
4
b,
c,
, deg
3
V,
The 3D set of X-ray diffraction data for structure
Ic was obtained on an autonomic fourcircle Nicolet
R3 diffractometer (MoK radiation, graphite mono-
Z
3
dcalc, g cm
1.342
1.02
Absorption coefficient,
chromator, /2 scanning, 2
55 ). The structure
1
was solved by the direct methmoadx (SIR2004 [35]) and
refined by full-matrix least squares anisotropically for
non-hydrogen atoms (SHELXL 97 [36]). Hydrogen
atoms were located by the difference Fourier synthesis
and refined isotropically. The drawings were per-
formed by the ORTEP-3 program [37].
, cm
Crystal dimensions, mm
Reflections
measured/independent
Fullness of data collec-
tion to
Method of refinement
Data/restrictions/
0.54 0.36 0.32
3230/3004 [Rint 0.0138]
100
27.55%
full-matrix MLS on F2
3004/0/232
Synthesis of fluorinated 2-benzoylcyclohexane-
1,3-diones Ia Ie. To a solution of 13.5 mmol of
cyclohexane-1,3-dione enol acylate IIa IIe in 10 ml
of acetonitrile, 27.0 mmol of triethylamine and 0.5 ml
of acetone cyanohydrin were added. The reaction mix-
ture was stirred at room temperature for 3 h (IIa IId)
or 0.5 h (IId), and 50 ml of chloroform was added to
the mixture. The chloroform solution was washed
parameters
Quality of refinement on F2
R [I > 2 (I)]
1.047
R1 0.0382, wR2 0.1029
R1 0.0499, wR2 0.1124
0.125 and 0.182
R1 (all data)
Max and min residual
peaks, e
3
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 10 2007

SYNTHESIS AND PROPERTIES OF FLUORINATED 2-BENZOYLCYCLOHEXANE-1,3-DIONES
1729
Table 5. Atomic coordinates ( 104) and equivalent iso- (1H, OH). 19F NMR spectrum, F, ppm: 112.6 m.
2
tropic thermal parameters (
103) in structure Ic
Found, %: C 68.57; H 5.71. C15H15FO3. Calculated,
%: C 68.69; H 5.76.
Atom
x/a
y/b
z/c
Ueq
2-(3-Fluorobenzoyl)-5,5-dimethylcyclohexane-
1,3-dione (Ib). Yield 87%, mp 88 90 C.IR spectrum,
C1
3275(2)
1665(1)
3813(2)
5636(2)
6133(1)
7154(2)
6731(2)
4786(2)
2507(2)
2917(2)
705(2)
3934(1)
4179(1)
3083(1)
2791(1)
1983(1)
3360(1)
4348(1)
4481(1)
2498(1)
1695(1)
2788(1)
2223(1)
2428(1)
3188(1)
3377(1)
3759(1)
3558(1)
4686(1)
4838(1)
2418(1)
2272(1)
1984(1)
2358(1)
2178(1)
2980(1)
2886(1)
3135(1)
1278(1)
1187(1)
576(1)
478(1)
240(1)
870(1)
1596(1)
812(1)
45(1)
67(1)
43(1)
45(1)
58(1)
51(1)
47(1)
49(1)
48(1)
66(1)
47(1)
56(1)
64(1)
62(1)
93(1)
62(1)
55(1)
61(1)
64(1)
1
, cm : 1675 (C=Oconjug), 1585 (C=Ochelat). 1H
O1
NMR spectrum, , ppm: 1.16 s (6H, 2CH3), 2.40 s
(2H, CH2, C6), 2.66 s (2H, CH2, C4), 7.19 d.d (1H,
Harom, C2 , J 9.0, 1.3 Hz), 7.20 m (1H, Harom, C4 ),
7.26 d.t (1H, Harom, C6 , J 7.9, 1.3 Hz), 7.37 m (1H,
Harom., C5 ), 16.83 br.s (1H, OH). 19F NMR spectrum,
F, ppm: 113.3 m. Found, %: C 68.35; H 5.81.
C15H15FO3. Calculated, %: C 68.69; H 5.76.
C2
C3
O3
C4
C5
C6
C7
O7
2-(4-Fluorobenzoyl)-5,5-dimethylcyclohexane-
C8
1,3-dione (Ic). Yield 79%, mp 135 137 C. IR spec-
1
C9
813(2)
trum, , cm : 1670 (C=Oconjug), 1565 (C=Ochelat).
C10
C11
F11
C12
C13
C14
C15
H3
2477(2)
2575(2)
4200(1)
1112(2)
539(2)
1H NMR spectrum, , ppm: 1.16 s (6H, 2CH3), 2.40 s
(2H, CH2, C6), 2.65 s (2H, CH2, C4), 7.08 m (2H,
Harom, C3 , C5 ), 7.55 m (2H, Harom, C2 , C6 ), 16.99
br.s (1H, OH). 19F NMR spectrum, F, ppm:
106.9 m. Found, %: C 68.41, H 5.82. C15H15FO3.
Calculated, %: C 68.69, H 5.76.
71(1)
1690(1)
3778(2)
6827(2)
8161(2)
5,5-Dimethyl-2-[4-(trifluromethyl)benzoyl]cyclo-
4860(30) 1681(12) 1747(17) 96(6)
8290(20) 3227(11) 2696(13) 71(5)
7380(20) 3180(10) 3813(14) 71(5)
4420(20) 5121(11) 3039(13) 70(4)
4800(20) 4303(10) 3949(14) 63(4)
690(20) 1700(10)
3580(30) 2037(13)
1240(30) 4302(12) 1262(16) 85(5)
1610(20) 3977(10) 3(13) 65(4)
hexane-1,3-dione (Id). Yield 73%, mp 102 105 C.
H4A
H4B
H6A
H6B
H9
1
IR spectrum, , cm : 1680 (C=Oconjug), 1555
1
(C=Ochelat). H NMR spectrum, , ppm: 1.16 s (6H,
2CH3), 2.39 s (2H, CH2, C6), 2.67 s (2H, CH2, C4),
7.57 d (2H, Harom, C3 , C5 , J 8.3 Hz), 7.65 d (2H,
Harom, C2 , C6 , J 8.3 Hz), 16.92 br.s (1H, OH). Found,
%: C 61.43, H 4.79. C16H15F3O3. Calculated, %: C
61.54, H 4.84.
946(13) 63(4)
309(16) 93(6)
H10
H12
H13
H14A 8100(30) 4583(11) 1512(14) 77(5)
2-(2,3,4,5,6-Pentafluorobenzoyl)-5,5-dimethyl-
H14B
H14C
5860(20) 4378(11) 1062(14) 71(5)
6540(30) 5339(14) 1634(15) 86(5)
cyclohexane-1,3-dione (Ie). Yield 72%, mp 53 55 C.
1
IR spectrum, , cm : 1700 (C=Oconjug), 1585
1
H15A 9410(30) 4744(12) 3627(14) 79(5)
(C=Ochelat). H NMR spectrum, , ppm: 1.14 s (6H,
2CH3), 2.35 s (2H, CH2, C6), 2.69 s (2H, CH2, C4),
H15B
H15C
7890(20) 5481(13) 3757(14) 80(5)
8140(30) 4570(12) 4577(16) 87(5)
16.35 br.s (1H, OH). 19F NMR spectrum, F, ppm:
142.78 m (2F, C2 ,C6 ), 152.27 t (1F, C4 , J 20 Hz),
161.70 m (2F, C3 , C5 ). Found, %: C 46.18, H 2.89.
with 10% HCl (3 20 ml) and water (2 20 ml) and C15H11F8O3. Calculated, %: C 46.05, H 2.83.
dried over magnesium sulfate. The solvent was
3-Benzoyloxycyclohex-2-en-1-ones IIa IIe were
removed under reduced pressure, and the residue was
prepared by a known method from 5,5-dimethylcyclo-
recrystallized from ether. Compounds Ia Ie were
hexane-1,3-dione and corresponding fluorobenzoyl
isolated as colorless crystals in 72 93% yields.
chlorides in the presence of pyridine in anhydrous
chloroform [22] and isolated by recrystallization from
ether hexane (2:1) as colorless crystals in 73 95%
yields.
2-(2-Fluorobenzoyl)-5,5-dimethylcyclohexane-
1,3-dione (Ia). Yield 93%, mp 105 107 C. IR spec-
1
trum,
,
cm : 1680 (C=Oconjug), 1575 (C=O
chelat.). 1H NMR spectrum, , ppm: 1.13 s (6H,
3-(2-Fluorobenzoyloxy)-5,5-dimethylcyclohex-2-
2CH3), 2.36 s (2H, CH2, C6), 2.63 s (2H, CH2, C4),
en-1-one (IIa). Yield 95%, mp 40 42 C (40 43 C
1
7.04 d.d.d (1H, Harom
,
C3 ,
J
10.3, 8.3,
[18]). IR spectrum, , cm : 1745 (C=O ester), 1680
1
1 Hz), 7.22 t.d (1H, Harom, C5 , J 7.7, 1 Hz), 7.43 m
(C=Oconjug), 1620 (C=C). H NMR spectrum, , ppm:
(1H, Harom, C6 ), 7.46 m (1H, Harom, C4 ), 16.90 br.s 1.16 s (6H, 2CH3), 2.33 s (2H, CH2, C6), 2.56 d (2H,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 10 2007

1730
KHLEBNIKOVA et al.
4
4
CH2, C4, J 1 Hz), 6.06 t (1H, Hvinyl, C2, J 1 Hz),
REFERENCES
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117.03 (C2), 117.15 d (C1 , JC F 22 Hz), 117.35 d (C3 ,
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135.82 d (C4 , JC F 9 Hz), 160.85 d (COO, JC F 4 Hz),
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1600 (C=C). H NMR spectrum, , ppm: 1.16 s (6H,
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IR spectrum, , cm : 1760 (C=O ester), 1670
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(C=Oconjug), 1625 (C=C). H NMR spectrum, , ppm:
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74 C. IR spectrum, , cm : 1760 (C=O ester), 1680
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SYNTHESIS AND PROPERTIES OF FLUORINATED 2-BENZOYLCYCLOHEXANE-1,3-DIONES
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