Phenylmethylene as intermediate in acid-catalyzed oxidation of styrene epoxide

Article abstract of DOI:10.1007/s11172-016-1605-7

The absorption spectrum of iminium ylide (λ_max = 450 nm) has been registered under the conditions of acid-catalyzed consumption of styrene epoxide under the influence of p-toluenesulfonic acid (MeCN, Bu^tOH (90 vol.%) + chlorobenzene (10 vol.%), 343 K) in the presence of pyridine. The spectrum coincides with the spectrum of the ylide product of the interaction of pyridine with phenylcarbene of phenylmethylene formed in the conventional flash-photolytic preparation of carbene from diazo derivative. The result confirms the earlier assumption on the formation of the particles of carbene nature reacting with oxygen in the epoxy-acid system. In the absence of O₂ these particles destruct introduced hydroperoxides. The spectra of corresponding carbonyl oxide (λ_max ≈ 408, 400 nm) in the presence and absence of pyridine were recorded in acetonitrile.

Full text of DOI:10.1007/s11172-016-1605-7

2452
Russian Chemical Bulletin, International Edition, Vol. 65, No. 10, pp. 2452—2457, October, 2016
Phenylmethylene as intermediate in acidꢀcatalyzed oxidation
of styrene epoxide
M. G. Spirin, S. B. Brichkin, and L. V. Petrov
Institute of Problems of Chemical Physics, Russian Academy of Sciences,
1
prosp. Akad. Semenova, 142432 Chernogolovka, Moscow Region, Russian Federation.
Eꢀmail: plv@icp.ac.ru
The absorption spectrum of iminium ylide (λmax = 450 nm) has been registered under the
conditions of acidꢀcatalyzed consumption of styrene epoxide under the influence of pꢀtoluenesulfonic
t
acid (MeCN, Bu OH (90 vol.%) + chlorobenzene (10 vol.%), 343 K) in the presence of pyridine.
The spectrum coincides with the spectrum of the ylide product of the interaction of pyridine
with phenylcarbene of phenylmethylene formed in the conventional flashꢀphotolytic preparation of
carbene from diazo derivative. The result confirms the earlier assumption on the formation of
the particles of carbene nature reacting with oxygen in the epoxyꢀacid system. In the absence
of O2 these particles destruct introduced hydroperoxides. The spectra of corresponding
carbonyl oxide (λmax ≈ 408, 400 nm) in the presence and absence of pyridine were recorded in
acetonitrile.
Key words: styrene epoxide, pꢀtoluenesulfonic acid, acetonitrile, tertꢀbutanol, pyridine, ylide,
phenylcarbene of phenylmethylene, molecular oxygen, carbonyl oxide of phenylmethylene.
Acidꢀcatalyzed process of styrene epoxide (1) conꢀ
The study of the triple system (ROOH—1—2) led to
t
sumption in polar media (Bu OH, MeCN) is the result
of competition between two proceeding parallel routes:
dominant heterolytic process (∼ 95%) and homolytic
the variant of stepwise conversion of epoxide with the
formation of triplet carbene as intermediate: protolysis
of 1 → carbocation → carbene—phenylmethylene (3) →
1
(
∼ 4—5%) process, which is able to produce active interꢀ
→ uptake of oxygen. Identity of the reaction orders of
mediates reacting with O forming benzaldehyde, and in
the 1 consumption for epoxide and acid in acidꢀcatalyzed
2
an Ar atmosphere destroy hydroperoxides (ROOH) at
process and uptake of O in this process, selective formaꢀ
2
43 K.1 High stability of pure epoxide 1 to the radicalꢀ
,2
tion of C H CHO, strong agreement of retardation of
3
6
5
3
chain oxidation (initiator, 413 K) is in marked contrast
to its lability in respect to oxygen in the presence of acid
at 343 K.2
homolytic and heterolytic conversion of epoxide 1 by
5
catalytic amounts of halides, are the indices that conꢀ
,4
firm this Scheme.
Acidꢀcatalyzed conversions of epoxides, in particular
compound 1, in polar media were considered for a long
time traditionally as purely heterolytic reactions. It has
However, the possibility of carbenes appearance as
the result of chemical reactions in these systems seemed
theoretically improbable. Calculations of the formation
heats of the compound 3 in the gas phase performed by
various methods showed a significant limitation of the
5
been found in detailed kinetic study of mild acidꢀcataꢀ
lyzed oxidation of epoxide 1 in a mixed solvent BUC
t
6,7
(
90 vol.% of Bu OH and 10 vol.% of chlorobenzene) that
thermochemical process.
heterolytic and homolytic routes of the consumption of 1
in the presence of pꢀtoluenesulfonic acid (2) are clearly
symbatic.
Experimental
4
Absorption spectra of studied solutions were registered at 298
and 343 K using fiber optic spectrometer HRꢀ2000 (Ocean Optiсs).
Integration time was set to 5 ms. The sensitivity of spectrometer at
studied wavelength was not less than 0.002. OOI Base32 software
was used for spectra processing. Working concentrations of the
reagents ([1] > [4] >> [2]) were selected on the basis of experiꢀ
0
1
—5
mental data obtained previously.
sealed quartz cuvettes (l = 1 cm) were flushed with dry argon for
0 min or, if required, by O . The heating of cuvettes (10 min) to the
Investigated solutions in the
2
2
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2452—2457, October, 2016.
066ꢀ5285/16/6510ꢀ2452 © 2016 Springer Science+Business Media, Inc.
1

Phenylmethylene in oxidation of styrene epoxide
Russ.Chem.Bull., Int.Ed., Vol. 65, No.10, October, 2016
2453
reaction temperature and temperature maintaining was performed
with the help of water thermostate. The registration of spectra was
carried out according to time plan. The oxidation rates (VO2) were
measured volumetrically according to earlier described procedure.5
Initial and final content of epoxide 1, and if required of benzaldeꢀ
hyde and phenylacetyl aldehyde (products of homolytic and heteroꢀ
Acidꢀcatalyzed conversion (net consumption) of epꢀ
oxide 1 in Ar and O atmospheres is undergoing practiꢀ
2
cally with a constant rate, at time zero order, almost to
4,11
complete disappearance of epoxide 1.
Thus, the kiꢀ
netic data for epoxide 1 consumption and oxygen uptake
allow us to suggest constant rate of the formation of
active particles for a considerable time period and miniꢀ
mum negative effect from the presence of the heterolysis
products of epoxide 1 under the conditions of system 1—2
(see Ref. 1). Also as the result of the all above mentioned
facts the accumulation of steadyꢀstate concentration of
ylide is sufficient for the observation.
The investigation of absorption spectra of the soluꢀ
tions of BS 1—2 in the presence of pyridine 4 at 343 K in
Ar atmosphere in BUC (Fig. 1, а, spectra 1—9 and 1´—4´)
and in MeCN (Fig. 1, b, spectra 1″—7″) has shown that
4
lytic conversion, respectively) were determined by HPLC.
The quality of reagents was controlled by HPLC, GC, and also
kinetically by the reproduction of earlier obtained data for the
oxidation in binary system (BS) 1—2. Epoxide 1 and pyridine (4)
were purified by vacuum distillation in Ar atmosphere. Chlorobenꢀ
zene was treated several time with H SO , then washed with water,
2
4
dried over CaCl , and distilled. MeCN (Acros Organics, HPLC
2
t
UV), Bu OH (Reachim, analytical grade), pꢀtoluenesulfonic acid
monohydrate (Reachim, pure) were used as received.
Results and Discussion
The reactions of electrophylic carbenes with comꢀ
pounds containing C=N bond with the formation of
iminium ylides as labile intermediates (Scheme 1) are
generally used to identify carbenes and to study their
reactivity. High rate of carbenes interaction with comꢀ
pound 4 is the basis of technique of the pyridine samꢀ
A
a
0
0
0
.4
.3
.2
2
98K
3´
7
pling. For example, k
for singlet state and triplet
4
state8
—10
9
–1 –1
of compound 3 consists of 1•10 L mol
s
and
6
–1 –1
4
9
.3•10 L mol
s
, respectively.
4´
8
9
5
6
0
.1
2
2´
Scheme 1
0
31
1´
4
00
450
500
550
600 λ/nm
A
7
″
0
0
0
.4
.3
.2
3
″
″
b
4
5
″
6
″
Iminium ylide (5) is a product of the reaction of
2″
5
´
pyridine with carbene obtained from diazo compounds
of corresponding structure using vacuum flashꢀthermolyꢀ
sis (FVT), laser flashꢀphotolysis (LFP) in solution or
solid matrix. The presence of this intermediate is regisꢀ
tered in UV or visible range of spectrum using highꢀ
speed spectroscopy (up to 400 ns due to small lifetime of
4´
6
´
2
´
0
.1
1
″
3´
1
´
1
2
3
4 5 6
0
4
00
450
500
550
600 λ/nm
8
,10
ylides) at room temperature in anaerobic conditions.
Fig. 1. Absorption spectra of BS 1—2 in the presence of 4 in
To detect carbene intermediate in the solutions of
epoxide 1 in the presence of compound 2 the pyridine
solutions (343 K, Ar): а is BUC (1—9) ([1]0 = 1.044, [1]KOH =
=
0.39, [2] = 0.0932, [4] = 0.4 mol L– ) at reaction time 180 (1),
1
3
00 (2), 480 (3), 600 (4), 780 (5), 900 (6), 1200 (7), 1800 (8),
was also used as a trap. In accordance with the literature
data,8
—10
2400 s (9). (1´—4´) is BUC ([1]0 = 1.044, [2] = 0.0233, [4] =
in the conditions of catalyzed consumption of
=
3
(
[
0.112 mol L– ) at reaction time 180 (1´), 300 (2´), 1800 (3´),
1
the epoxide 1 (343 K) in epoxyꢀacid system (1—2) in
polar media (MeCN or BUC), and in Ar atmosphere,
the formation of compound 3 in the presence of 4 should
be manifested in the characteristic absorption band of
pyridinium ylide 5 (see Scheme 1) in the spectrum.
–
1
600 s (4´); b is MeCN (1—6) at [2] = 0.034, [4] = 0.2 mol L ;
–1
1´—6´) at [1] = 0.52, [4] = 0.2 mol L ; (1″—7″) at [1] = 0.52,
0
0
–1
1]KOH = 0.43, [2] = 0.034, [4] = 0.2 mol L . Reaction time (s):
600 (1, 1´,1″), 1200 (2, 2´, 2″), 1800 (3, 3´, 3″), 2400 (4, 4´, 4″),
3000 (5, 5´, 5″), 3600 (6, 6´, 6″), 4200 (7″).

2
454 Russ.Chem.Bull., Int.Ed., Vol. 65, No. 10, October, 2016
Spirin et al.
at [4] ≥ 0.2 mol L–1 stable increase of the optical density in
A
the range of 430—480 nm corresponding to absorption of
phenylꢀsubstituted ylides is registered in time. This has
8
0.4
a
not been observed (see Fig. 1, b, spectra 1—6 and 1´—6´)
in the spectra of pairs 2—4 and 1—4 in the absence of one
of the components of binary epoxyꢀacid system, particuꢀ
larly epoxide 1.
0
.3
The choice of working concentration of pyridine in
solutions of MeCN and BUC allowed to select the comꢀ
promise conditions of experiments: comparability of rates
of consumption of the active particles in competing reacꢀ
tions, also with the trap 4, and acceptable threefold deꢀ
crease in the acidity of the solution in the presence of the
base 4. Characteristic bands of ylides (430—480 nm) do
not appear in the absorption spectra of BS 1—2 in O2
atmosphere in the presence of compound 4 (Fig. 2, a,
spectra 1—8 and Fig. 3, a, spectra 1—8). This fact is due
to fast reaction of the carbene with oxygen. Triplet
arylcarbene intermediates react with O2 by several orꢀ
0.2
7
6
5
4
0.1
3
2
8
1
4
00
450
500
550 λ/nm
A
4
b
0.01
3
A
a
0
0
0
.4
.3
.2
0
2
1
8
5
7
–0.01
6
5
1
4
3
4
50
500
550
600 λ/nm
Fig. 3. Absorption spectra in BUC at 343 K: а is BS 1—2 in the
presence of 4 ([1]0 = 1.044, [2] = 0.0932, [4] = 0.4 mol L–1), O2,
0
.1
2
1
at reaction time 180 (1), 300 (2), 480 (3), 600 (4), 780 (5), 900 (6),
1
1
200 (7), 1800 s (8), [1]KOH = 0.388 mol L– ; b is for compound 5,
0
as the result of subtraction of absorption spectra of system BS 1—2 + 4
4
00
450
500
550
600 λ/nm
in Ar and O atmospheres, at reaction time 600 (1), 780 (2), 900
2
(
3), 1200 (4), 1800 s (5).
A
0
0
0
.4
.3
.2
ders of magnitude faster than with pyridine (4): for
b
2
98K
example, for diphenylmethylene in MeCN k
=
=
4
5
–1 –1
298K
=
=
2.8—4.2•10 L mol
s
(see Ref. 12), and kO2
7
9
–1 –1
13
5•10 L mol
s
(LFP). For the same reason hydroꢀ
peroxides introduced into BS 1—2 are not destroyed in
8
1
6
the O atmosphere.
2
Phenylꢀsubstituted pyridinium ylides have weak abꢀ
sorption bands.9 The initial view of the spectra obꢀ
tained in BS is complicated by the background absorpꢀ
tion associated with the accumulation of epoxide 1 conꢀ
version products (see Figs 1 and 2). The background
removing was performed in two ways. In the first case,
from the optical density of the absorption spectra of
BS—4 system in Ar atmosphere the values of absorption
obtained for this system at similar reaction conversion in
the O2 atmosphere were subtracted (Fig. 4, a, spectra
1—7 and Fig. 3, b, spectra 1—5). In the second case, the
values of absorption measured in the absence of trap 4
9
,10
5
4
3
2
0
.1
1
0
4
00
450
500
550
600 λ/nm
Fig. 2. Absorption spectra of BS 1—2, MeCN, 343 K: а is in the
presence of 4, [1] = 0.52, [2] = 0.034, [4] = 0.2 mol L , O , at
reaction time 300 (1), 600 (2), 900 (3), 1500 (4), 2400 (5), 3000 (6),
–
1
0
2
= 0.42 mol L–1; b, at [4] = 0, [1] =
3
=
6
600 (7), 4200 s (8). [1]
KOH 0
0.52, [2] = 0.0106 mol L– , Ar, at reaction time 300 (1), 480 (2),
00 (3), 900 (4), 1200 (5), 1800 (6), 2400 (7), 3000 (8), 3600 s (9).
1

Phenylmethylene in oxidation of styrene epoxide
Russ.Chem.Bull., Int.Ed., Vol. 65, No.10, October, 2016
2455
A
nm in aprotic MeCN with increasing of time of spectra
recording (see Fig. 4, a). In alcoholic BUC medium (λmax
a
0
.15
.10
4
=
450 nm) that shift is not detected even at three times
higher degree of the epoxide decomposition (see Fig. 3,
b).
3
5
An increase in the concentration of pyridine (4) in
2
6
0
MeCN decreases the O uptake rate by BS solutions 1—2
2
1
4
in the oxygen atmosphere. The uptake rate is indicator
of the active particles generation. The presence of comꢀ
pounds 1, 2, and 4 in solutions should lead to several
equilibrium acidꢀbase processes with the participation
7
1
0
.05
1
4
of these compounds. Complete neutralization of comꢀ
pound 2 by the base does not take place here (see Fig. 1, b,
spectra 1´—6´ and 1″—7″). In order to calculate reaction
rate in this experiment the dependence of VO2 on the
concentration of compound 4 from the Ref. 14, obtained
in similar condition and with the same batches of reꢀ
4
00
450
500
550
600 λ/nm
A
b
0
0
0
.08
.06
.04
–
1
2
agents, was used. Input of 0.2 mol L of compound 4, at
–
1
[
2] = 0.034 mol L , decreases the value of V by 3.1
O2
–
6
–1 –1
–6
–1 –1
times, from 16.0•10 mol L
s
to 5.2•10 mol L
s .
Consequently, taking into account equality of the rates of
1
net epoxide 1 consumption in argon and oxygen atmoꢀ
4
,11
spheres,
this fact provides for the decrease of the
intermediate generation in Ar atmosphere by 3.1 times.
Then taking into account zero order of oxidation reacꢀ
tion for epoxide and first reaction order for acid4 the
spectrum for control subtraction by second method was
registered in three times smaller content of compound 2
3
4
5
6
4
50
500
550
600 λ/nm
–
1
(
0.0106 mol L ). This procedure (see Fig. 4, b) provides
Fig. 4. Absorption spectra of compound 5 in MeCN (343 K),
obtained by subtraction of the absorption values of the system using
first and second procedures: а is BS 1—2 + 4 in Ar and O
atmospheres ([1] = 0.52, [2] = 0.034, [4] = 0.2 mol L ) at
for the comparison at lower reaction conversion. Howꢀ
ever, the maxima of resulting spectra of compound 4
reaction products with identified carbene intermediate,
obtained by the second method (Ar atmosphere) are close
2
–
1
0
reaction time 600—600 (1), 1200—900 (2), 1800—1500 (3), 2400—
2
400 (4), 3000—3000 (5), 3600—3600 (6), 4200—4200 s (7);
–
1
b is BS 1—2 + 4 ([1] = 0.52, [2] = 0.034, [4] = 0.2 mol L ) and
BS 1—2 ([1] = 0.52, [2] = 0.0106 mol L , Ar) at reaction time
0
–
1
A
0
0
0
0
0
.06
.05
.04
.03
6
00 (1), 1200 (2), 1800 (3), 2400 (4), 3000 (5), 3600 s (6).
1
2
(
in Ar atmosphere) at similar rate of generation of reactive
intermediates were subtracted (see Fig. 4, b). Obtained in
these ways difference spectra for BUC and MeCN soluꢀ
tions (343 K) contain well pronounced band with a maxiꢀ
mum at 440—450 nm, characteristic of the reaction prodꢀ
uct of active intermediate with pyridine 4 (see Figs 3 and
4
). The amplitudes of noise in this case are many times
smaller than amplitudes of bands in the obtained spectra.
The nature of the spectra obtained by subtracting usꢀ
ing the first method (see Fig. 3, b and Fig. 4, a) both in
MeCN and in BUC shows that the constant concentraꢀ
tion of the new compound is established in the system for
the time ≤10 min. This observation is consistent with the
zero order consumption of epoxide 1 and constant rate of
4
00
450
500
550
600 λ/nm
Fig. 5. Comparison of the absorption spectra of compound 5 (1, 2)
in MeCN at 343 K, obtained by subtraction of the absorption values
using first and second procedures (reaction time 600 s) for systems:
BS 1—2 + 4 ([1] = 0.52, [2] = 0.034, [4] = 0.2 mol L ) in Ar and
O atmospheres (1), and also BS 1—2 + 4 ([1] = 0.52, [2] =
–1
0
2
0
1
1
–1
the O uptake. The peculiarity of the solvent used is
= 0.034, [4] = 0.2 mol L ) and BS (1–2) ([1] = 0.52, [2] =
= 0.0106 mol L–1) in Ar atmosphere (2).
2
0
manifested by a small hypsochromic shift from 450 to 440

2
456 Russ.Chem.Bull., Int.Ed., Vol. 65, No. 10, October, 2016
Spirin et al.
Scheme 2
to the estimate data obtained using of the first method
Ar, O atmospheres), 450 and 445 nm, respectively (see
Fig. 5, spectra 1—2).
compound 6 (Fig. 6, a, spectra 1—6). As in the case of
compound 5, the time variation of the intensity of the
absorption band is small. It allows us to suggest that in
the system (at [1]final > 0) the stationary concentration of
compound 6 is established. In the absence of pyridine,
similarly, in the same area of 390— 420 nm the similar
band with close peak at 400—403 nm appears in
the spectrum of a binary system 1—2 in oxygen atmoꢀ
sphere (Fig. 6, b). The data are not sufficient to calculate
the value of εROO (molar extinction coefficient), but a
rough quantitative estimate based on the values of εROO
(
2
The values of absorption maxima in polar media obꢀ
tained in two ways of subtraction are close to the values
for compound 5 obtained via laser flashꢀphotolysis at
1
0
room temperature: 460 nm (nꢀpentane), 474 nm
9
8
(
freonꢀ113), 450 nm. . A small shift of maximum in our
conditions is explained by hypsochromic shift in the poꢀ
lar solvent.
Carbonyl oxides (CО) (Scheme 2) are primary prodꢀ
ucts of the oxidation reaction of triplet aromatic
carbenes in oxygen atmosphere.13,15 Characteristic
for arylꢀsubstituted CО published in Ref. 16 ((ε
=
ROO
–1
–1
= 1400±500 L mol cm ) is possible. Supposing that
spectra of CО, labile intermediates of the oxidation reacꢀ
ΔAλmax = ε•l•m,
tion, are known for many cases in MeCN.1
the carbonyl oxide of phenylmethylene (6) λ
of 407±20 nm.1
5—18
Thus, for
consists
max
where ΔA is the change of absorption at λmax; l is the
λ
5,17,18
cuvette length, cm; m is the concentration of determined
intermediate, mol L . For values of ΔAλmax
–
1
+Py
The spectra of the system 1—2 + 4 + O in MeCN,
= 0.01 (see
2
obtained by the first method of subtraction of the backꢀ
ground absorption, but in the reverse order, i.e. AO2—AAr,
exhibit a weak absorption band of the reaction intermeꢀ
diate in the range of 390—420 nm, which at the average
maximum (408 nm) corresponds to the absorption of
Fig. 6, a), ΔAλmax = 0.03 (see Fig. 6, b), for systems (1—2) +
+ 4 + O and (1—2) + O in MeCN we obtain the values
of m = 7.1•10 and 2.1•10 mol L , respectively. The
2
2
–
6
–5
–1
formation of compound 6 in BS 1—2 + O explains fast
2
oxidation of introduced into the system readily oxidizable
A
A
–0.10
1
b
–
–
–
0.07
0.08
0.09
a
–0.15
2
6
–
0.20
–0.25
–0.30
–0.35
–0.40
3
1
–
0.10
0.11
0.12
2
4
3
–
5
4
–
4
00 410 420 430 440 450 460
λ/nm
400
425
450
475 λ/nm
Fig. 6. Absorption spectra of compound 6 in MeCN at 343 K: а is difference of optical densities of BS 1—2 + 4 in Ar and O atmospheres
2
–
1
(
3
[1] = 0.52, [2] = 0.034, [4] = 0.2 mol L ) at reaction time 1200—900 (1), 1800—1500 (2), 2400—2400 (3), 3000—3000 (4), 3600—
0
600 (5), 4200—4200 s (6); b — difference of optical densities of BS 1—2 in Ar and O atmospheres ([1] = 0.52, [2] = 0.015 mol L ) at
–
1
2 0
reaction time 600 (1), 900 (2), 1200 (3), 1800 s (4).

Phenylmethylene in oxidation of styrene epoxide
Russ.Chem.Bull., Int.Ed., Vol. 65, No.10, October, 2016
2457
substrates, such as styrene or isopropanol.19
8. A. F. Khlebnikov, M. S. Novikov, R. R. Kostikov, Russ. Chem.
Rev. (Engl. Transl.), 2005, 74, 171 [Usp. Khim., 2005, 74, 183].
Thus, the data of presented spectral study of BS 1—2
in the presence and absence of the chemical traps (pyriꢀ
dine and oxygen) indicate the formation of carbene and
carbonyl oxide in the system. Pyridinium ylide of
phenylmethylene is detected in the system (1—2) + 4 in
Ar atmosphere, and carbonyl oxide of phenylmethylene
is detected in oxygen atmosphere. This confirms the earꢀ
lier assumption1 on the oxidation of binary epoxyꢀacid
system without the formation of peroxide radicals.
9. A. Admasu, A. D. Gudmundsdottir, M. S. Platz, J. Phys. Chem.
A, 1997, 101, 3832.
1
0. A. Admasu, M. S. Platz, A. Marcinek, J. Michalak, A. D.
Gudmundsdottir, J. Gebicki, J. Phys. Org. Chem., 1997, 10, 207.
1. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
013, 53, 326 [Neftekhim., 2013, 53, 369].
1
2
12. M. B. Jones, M. S. Platz, Tetrahedron Lett., 1990, 31, 953.
13. J. C. Scaiano, W. G. McGimpsey, H. L. Casal, J. Org. Chem.,
1989, 54, 1612.
1
4. L. V. Petrov, V. M. Solyanikov, Russ. Chem. Bull. (Int. Ed.),
015, 64, 107 [Izv. Akad. Nauk, Ser. Khim., 2015, 107].
5. W. H. Bunnelle, Chem. Rev., 1991, 91, 335.
6. A. M. Nazarov, E. M. Chainikova, I. A. Kalinichenko, S. L.
2
References
1
1
1
2
3
4
5
6
. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
005, 45, 202 [Neftekhim., 2005, 45, 225].
. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
010, 50, 437 [Neftekhim., 2010, 50, 447].
. L. V. Petrov, B. L. Psikha, V. M. Solyanikov, Petroleum Chem.
Engl. Transl.), 2009, 49, 245 [Neftekhim., 2009, 49, 263].
. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
999, 39, 89 [Neftekhim., 1999, 39, 107].
. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
012, 52, 327 [Neftekhim., 2012, 52, 362].
Hursan, R. L. Safiullin, V. D. Komissarov, Russ. Chem. Bull.
(Engl. Transl.), 1999, 48, 672 [Izv. Akad. Nauk, Ser. Khim.,
1999, 677].
2
2
17. D. Cremer, T. Schmidt, W. Sander, P. Bischop, J. Org. Chem.,
1989, 54, 2515.
18. I. А. Kalinichenko, PhD Thesis (Chem.), Institute of Organic
Chemistry of Ufa Scientific Center of Russian Academy of
Sciences, Ufa, 1999, 161 pp. (in Russian).
(
1
19. L. V. Petrov, V. M. Solyanikov, Petroleum Chem. (Engl. Transl.),
1998, 38, 117 [Neftekhim., 1998, 38, 128].
2
. Yu. D. Orlov, Yu. A. Lebedev, L. G. Menchikov, O. M.
Nefedov, Russ. Chem. Bull. (Engl. Transl.), 1997, 46, 52 [Izv.
Akad. Nauk, Ser. Khim., 1997, 57].
7
. T. L. Nguyen, G.ꢀS. Khim, A. M. Mebel, M. T. Nguen, Chem.
Phys. Lett., 2001, 349, 571.
Received September 21, 2015;
in revised form May 31, 2016