Synthesis of 9-oxoselenoxanthenium and triarylselenonium hexafluorophosphates

Article abstract of DOI:10.1134/S1070363215050163

The selenoxides forming 9-oxoselenoxanthenium and triaryl selenonium hexafluorophosphates via interaction with heptyl phenyl ether and anisole in the MeSO₃H-P₂O₅ mixture followed by treatment with KPF₆ have been obtained via selenoxantene-9-one and diphenyl selenide derivatives oxidation with m-chloroperoxybenzoic acid or hydrogen peroxide.

Full text of DOI:10.1134/S1070363215050163

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 5, pp. 1093–1097. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © V.A. Loskutov, S.V. Balina, V.V. Russkikh, V.V. Shelkovnikov, 2015, published in Zhurnal Obshchei Khimii, 2015, Vol. 85, No. 5,
pp. 796–800.
Synthesis of 9-Oxoselenoxanthenium
and Triarylselenonium Hexafluorophosphates
V. A. Loskutova, S. V. Balinaa, V. V. Russkikha, and V. V. Shelkovnikova,b
a Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 9, Novosibirsk, 630090 Russia
е-mail: val@nioch.nsc.ru
b Tomsk State University, Tomsk, Russia
Received December 29, 2014
Abstract—The selenoxides forming 9-oxoselenoxanthenium and triaryl selenonium hexafluorophosphates via
interaction with heptyl phenyl ether and anisole in the MeSO3H–P2O5 mixture followed by treatment with KPF6
have been obtained via selenoxantene-9-one and diphenyl selenide derivatives oxidation with m-chloroperoxy-
benzoic acid or hydrogen peroxide.
Keywords: selenoxanthen-9-one, diaryl selenide, diaryl selenoxide, aryl(hetaryl)selenonium hexafluorophosphate
DOI: 10.1134/S1070363215050163
Onium (iodonium, sulfonium, or ammonium) salts
are used as initiators of cationic and radical photo-
polymerization [1–4]. The most common compounds
of this class are triarylsulfonium salts [5–9] and
sulfonium derivatives based on sulfur-containing hetero-
cyclic compounds (thioxanthene, thianthrene, benzothio-
phene, etc.) [10–14]; they are interest in view of
holography, acid generators for photoresists, and
photochemical detritylation in microchip oligonucleo-
tide synthesis applications.
(benzene or m-xylene) in 90% sulfuric acid to forma-
tion of selenoxanthenones IIa and IIb that were further
converted into the corresponding selenoxides (IIIa and
IIIb) in the course of oxidation with m-chloro-
peroxybenzoic acid. Noteworthily, in contrast to the
sulfur analogs, diaryl selenides are not overoxidized
into selenones [20]; hence, formation of compounds
IIIa and IIIb went smoothly and the yields were good.
Reaction of the obtained selenoxides with heptyl
phenyl ether in a 10 : 1 methanesulfonate–phosphoric
anhydride mixture followed by treatment with aqueous
solution of KPF6 yielded selenoxanthenium hexafluoro-
phosphates IVa and IVb (Scheme 1).
Introduction of heavy atoms in the photoinitiator
molecule enhances the singlet-triplet S1–T1 conversion
in the excited state [15, 16]. Since photochemical
reactions often involve the triplet state of the reactant,
substitution of sulfur in organic sulfonate salts with
heavier atoms (for example, selenium or tellurium) can
improve their photochemical activity.
We further extended the above-described procedure
to prepare triaryl selenonium derivatives. Those com-
pounds have been better described in the literature as
compared to the selenoxanthene salts. A classic method
of their synthesis consists in the interaction of aromatic
hydrocarbons with selenium dioxide or diarylsele-
niumdichloride in the presence of AlCl3 (the Friedel–
Crafts reaction) [21]. Triaryl selenonium compounds
can be prepared in the absence of AlCl3 as well, for
example, upon heating of anisole and selenium dioxide
in trifluoroacetic acid [22]. Other methods of triaryl
selenonium salts synthesis are arylation of diaryl
selenides with diaryl iodonium salts catalyzed by
copper [23, 24] and condensation of organometallic
compounds (Grignard reagent and others) with
We have earlier suggested application of thio-
xanthene hexafluorophosphate synthesized via reaction
of S-oxides of substituted thioxanthene-9-ones with
activated aromatic compounds as photoinitiators [17,
18]. This work aimed to extend the approach to
prepare the selenonium salts with selenoxide deriva-
tives of selenoxanthene-9-one and diaryl selenides as
an example. To the best of our knowledge, the related
information has been absent in the reference literature.
Similarly to dithiosalicylic acid [19], diseleno-
salicylic acid I reacted with aromatic hydrocarbons
1093

1094
LOSKUTOV et al.
Scheme 1.
R
O
O
COOH
R
R
[O]
R
90% H2SO4
Se
Se
Se
O
Se
COOH
R
R
I
IIа, IIb
IIIа, IIIb
O
R
−
PF6
+
Se
R
OC7H15
IVа, IVb
R = Н (а), СН3 (b).
Scheme 2.
O
Se
Se
H2O2
R
R
R
R
Dioxane
Vа−Vc
VIа−VIc
OCH3
(1) PhOCH3, MeSO3H−P2O5
−
PF6
(2) KPF6
Se+
R
R
VIIа−VIIc
R = H (а), 3-OCH3 (b), 4-OCH3 (c).
selenium oxochloride or diaryl selenoxides [25–28]. A
significant drawback of those methods is the use of
hardly accessible and insufficiently stable selenium
derivatives [21]. Therefore, the method of synthesis
aryl-substituted selenonium salts via the reaction of
diaryl selenoxides with activated aromatic compounds
seems advantageous.
VIa–VIc via oxidation with hydrogen peroxide were
used as starting compounds. Their interaction
with anisole in the MeSO3H–P2O5 mixture followed by
treatment with KPF6 gave triarylselenonium hexa-
fluorophosphates VIIa–VIIc in yields of 70–80%
(Scheme 2).
Hexafluorophosphates IV and VII were colorless
crystalline compounds soluble in organic solvents and
insoluble in water.
Diphenyl selenide Va and its methoxy derivatives
Vb and Vc converted into corresponding selenoxides
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015

SYNTHESIS OF 9-OXOSELENOXANTHENIUM
1095
Composition and structure of the products were
confirmed by chemical analysis and spectral data. H
192°C (191–192°C [32]). IR spectrum, ν, cm–1: 1634
1
1
(C=O). H NMR spectrum (400 MHz), δ, ppm: 7.45
3
4
NMR spectrum of unsubstituted seleniumoxanthenone
IIa contained weak-field signals of H1 and H8 protons
at carbon atoms adjacent to the carbonyl group at
8.63 ppm. In the case of 2,4-dimethyl derivative IIb,
the signal of the H8 proton was found at 8.60 ppm, and
the signal of H1 proton revealed a slight upfield shift to
8.34 ppm, the signal position clearly showing de-
shielding influence of the carbonyl group; hence, the
compound was identified as the 2,4-dimethyl derivative
rather than the isomeric 1,3-disubstituted selenoxanthene.
and 7.52 (4H, H2,3,6,7, JHH 8.0, JHH 2.0 Hz), 7.62 d.d
(2H, H4,5, JHH 8.0, JHH 2.0 Hz), 8.63 d.d (2H, H1.8,
3
4
3JHH 8.0, 4JHH 2.0 Hz).
2,4-Dimethyl-9H-selenoxanthene-9-one (IIb) was
prepared similarly from 1 g of diselenide I and 3 mL of
m-xylene; heating at 130–135°C during 25 h. Yield 0.5 g
(35%), mp 128–131°C. IR spectrum, ν, cm–1: 3061,
2920, 2853, 2737 (C–H), 1630 (C=O), 1587 (C=C). 1H
NMR spectrum (400 MHz), δ, ppm: 2.42 s and 2.46 s
4
(6H, 2Me), 7.28 d (1H, H3, JHH 2.0 Hz), 7.44 t.d and
7.51 t.d (2H, H6,7, 3JHH 8.0, 4JHH 1.5 Hz), 7.64 d.d (1H,
In summary, reaction of selenoxide based on aryl
(hetaryl) selenides with activated aromatic compounds
(anisole or heptyl phenyl ether) in a MeSO3H–P2O5
mixture is a simple and convenient method to prepare
promising photoinitiators, aryl(hetaryl)selenonium salts.
3
4
4
H5, JHH 8.0, JHH 1.5 Hz), 8.34 d (1H, H1, JHH
2.0 Hz), 8.60 d.d (1H, H8, 3JHH 8.0, 4JHH 1.5 Hz). Mass
spectrum: m/z 284.0078 [M]+ (calculated for
С15Н12О76Sе: M 284.0075).
Oxidation of selenoxanthenes (II) with m-chloro-
perbenzoic acid. A solution of 4 mmol m-chloro-
perbenzoic acid in 15 mL of chloroform was added to
a cooled (0°C) solution of 2 mmol of selenoxanthene
II in 10 mL of chloroform. The mixture was stirred
during 30 min, washed with 5% aqueous NaOH and
with water. The solution in chloroform was dried,
about 20 mL of the solvent was distilled off, diethyl
ether was added to the residue, and precipitate of the
oxide III was separated off.
EXPERIMENTAL
IR spectra of KBr pellets were recorded using a
Vector 22 spectrometer. NMR spectra of CDCl3 solu-
tions were registered with a Bruker AV-300 [300.13
(1Н) and 282.36 МHz (F19)] or an АМ-400 (400.13 МHz)
spectrometers with residual solvent protons being the
internal reference. 19F chemical shifts are reported
relative to the external C6F6 reference. Mass-spectra
were registered using a Thermo Fisher Scientific DFS
high-resolution mass spectrometer. The reaction
progress and the products purity were evaluated by
TLC on Sorbfil plates with chloroform as eluent. Silica
gel (the 50–160 µm fraction) was used for column
chromatography.
9H-Selenoxanthene-9-one-10-oxide (IIIa). Yield
64%, mp 237 to 240°C (mp 236–237°C [32]). IR
spectrum, ν, cm–1: 1666 (C=O), 806 (Se=O) (805 [33]).
1H NMR spectrum (400 MHz), δ, ppm: 7.72 t.d and
3
4
7.80 t.d (4H, H2,3,6,7, JHH 8.0, JHH 1.3 Hz), 8.08 d.d
(2H, H4,5, JHH 8.0, JHH 1.3 Hz), 8.38 d.d (2H, H1,8,
3
4
Bis(2-carboxyphenyl) diselenide (I) was obtained
from anthranilic acid and potassium polyselenide [29];
mp 299–301°C (ethanol) (304–306°C [29], 296–297°C
[30], and 358–360°C [31]). 1H NMR spectrum
coincided with the reference ones [29, 31]. Mass spec-
3JHH 8.0, JHH 1.3 Hz). Mass spectrum: m/z 273.9687
4
78
[M]+ (calculated for С13Н8О2 Sе: M 273.9692).
2,4-Dimethyl-9H-selenoxanthene-9-one-10-oxide
(IIIb). Yield 87%, mp 198–200°C. IR spectrum, ν,
cm–1: 3055–2730 (C–H), 1657 (C=O), 800 (Se=O). 1H
NMR spectrum (400 MHz), δ, ppm: 2.45 s and 2.82 s
(6H, 2Me), 7.39 d (1H, H3, 4JHH 2.0 Hz), 7.71 t.d and
7.78 t.d (2H, H6,7, 3JHH 8.0, 4JHH 1.5 Hz), 8.00 d.d (1H,
78
trum: m/z 397.8925 [M]+ (calculated for С14Н10О4 Se2:
M 397.8920).
9H-Selenoxanthene (IIa). 5 mL of anhydrous
benzene was added to a mixture of 1 g of diselenide I
and 25 mL of 90% H2SO4 cooled to 0°C, the mixture
was stirred during 3 h, incubated at room temperature
during 20 h, and then heated during 6 h at 50°C and
during 25 h at 80–85°C. The mixture was cooled and
poured onto ice. The precipitate was filtered off,
washed sequentially with water, 5% aqueous NaOH,
and water, and subject to chromatographic purification
eluting with chloroform. Yield 0.5 g (38%), mp 190–
3
4
4
H5, JHH 8.0, JHH 1.5 Hz), 8.13 d (1H, H1, JHH
2.0 Hz), 8.41 d.d (1H, H8, JHH 8.0, JHH 1.5 Hz). The
mass spectrum, m/z (Irel, %): 302 (1.74), 300 (0.77), 286
(35.51), 284 (13.01), 208 (100.00). Found, %: C 59.13;
H 3.76. С15Н12О78Sе. Calculated, %: C 59.40; H 3.96.
3
4
Diphenyl selenide (Va) was prepared from aniline
and potassium polyselenide [34], bp 165–167°C
(12 mmHg) {bp 165–167°C (12 mmHg) [34]}.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015

1096
LOSKUTOV et al.
Bis(3-methoxyphenyl)selenide (Vb) was prepared
2,4-Dimethyl-9-oxo-10-(4-hepthyloxyphenyl)-
9H-selenoxantenium hexafluorophosphate (IVb).
Yield 84%, mp 149–153°C. IR spectrum, ν, cm–1:
2953, 2928, 2856 (C–H), 1663 (C=O), 841, 557 (P–F).
1H NMR spectrum, δ, ppm: 0.86 m (3H, CH3CH2),
1.25 m (8H, 4CH2), 1.69 m (2H, CH2), 2.53 s and 2.61
s (6H, 2Me), 3.89 m (2H, OCH2), 6.90 d and 7.45 d
similarly from m-anisidine and potassium poly-
selenide. Yield 30%, bp 169–171°C (1 mmHg) {bp
169°C (1 mmHg) [35]}.
Bis(4-methoxyphenyl)selenide (Vc) was obtained
from anisole and SeCl2 [36]. Yield 90%, mp 54–55°C
(mp 54–55°C [20]).
3
4
(4H, C6H4, JHH 9.0 Hz), 7.55 d (1H, H3, JHH 2.0 Hz),
7.85 m (2H, H6,7), 8.17 m (1H, H5), 8.34 (1H, H1, 4JHH
2.0 Hz), 8.56 m (1H, H8). 19F NMR spectrum, δF, ppm:
90.5 d (JFP 711 Hz). Found, %: F 18.40; Se 12.88.
C28H31O2Se·PF6. Calculated, %: F 18.30; Se 12.68.
Diaryl selenoxides (VIa–VIc) were prepared via
oxidation of diaryl selenides Va–Vc with H2O2 (d =
1.145 g/mL) as described in [37].
Diphenyl selenoxide (VIa). Yield 86%, mp 110°C
(mp 109°C [38]).
Diphenyl(4-methoxyphenyl)selenonium, bis(3-meth-
oxyphenyl)(4-methoxyphenyl)selenonium, and tris-
(4-methoxyphenyl)selenonium hexafluorophosphates
(VIIa–VIIc) were prepared similarly from 1 mmol of
selenoxide VI and 1.5 mmol of anisole.
Bis(3-methoxyphenyl) selenoxide (VIb). Yield
61%, mp 131–132°C (precipitated with diethyl ether
from methylene chloride). IR spectrum, ν, cm–1: 829
(Se=O). 1H NMR spectrum (300 MHz), δ, ppm.: 3.79 s
Compound VIIa. Yield 77%, mp 131–132°C (pre-
3
4
(6H, 2OMe), 6.94 d.d. d (2H, H4,4', JHH 7.8, JHH 2.7,
cipitated with diethyl ether from methylene chloride).
1.2 Hz), 7.18 d. t (2H, H6,6', 3JHH 7.8, 4JHH 1.2 Hz), 7.27
1
IR spectrum, ν, cm–1: 839, 557 (P–F). H NMR spec-
d.d (2H, H2,2', J 2.7, 1.2 Hz), 7.32 t (2H, H5,5', JHH
7.8 Hz). Found, %: C 54.15; H 4.56; Se 25.74.
C14H14O3Se. Calculated, %: C 54.39; H 4.56; Se 25.53.
4
3
trum (300 MHz), δ, ppm: 3.85 s (3H, OMe), 7.12 d
(2H, H3,5, 3JHH 9.0 Hz), 7.49 m (6H, HAr), 7.64 m (6H,
HAr). 19F NMR spectrum, δF, ppm: 89.9 d (JFP 758 Hz).
Found, %: F 23.48; Se 16.4. C19H17OSe·PF6. Cal-
culated, %: F 23.49; Se 16.3.
Bis(4-methoxyphenyl) selenoxide (VIc). Yield
67%, mp 144°C (mp 144°C [37]).
Compound VIIb. Yield 71%, mp 152–153°C (pre-
Interaction of selenoxides of selenoxanthenone
(III) with heptyl phenyl ether. A mixture of 1.5
mmol of selenoxide III, 1.8 mmol of heptyl phenyl
ether, and 5 mL of a P2O5–MeSO3H (1 : 10) mixture
was stirred at 20°C during 5 h, incubated during 20 h
without stirring, cooled with icy water, and a solution
of 2 mmol of KPF6 in 5 mL of water was added
dropwise. The mixture was stirred during 30 min and
extracted with СН2Cl2. The organic layer was washed
with aqueous solution of KPF6 and water, evaporated,
and treated with diethyl ether; precipitate of hexa-
fluorophosphate IV was separated.
cipitated with diethyl ether from methylene chloride).
1
IR spectrum, ν, cm–1: 843, 557 (P–F). H NMR spec-
trum (300 MHz), δ, ppm: 3.62 s (6H, 2OMe), 3.69 s
3
4
(3H, OMe), 6.83 d.d. d (2H, H4',4", JHH 8.2, JHH 2.0,
0.2 Hz), 6.94 t (2H, H2',2", JHH 2.0 Hz), 6.96 d (2H,
4
H3,5, 3JHH 9.0 Hz), 7.02 d.d. d (2H, H6',6", 3JHH 8.2, 4JHH
2.0, 0.8 Hz), 7.33 d (2H, H2,6, 3JHH 9.0 Hz), 7.35 t (2H,
H5',5", 3JHH 8.2 Hz). 19F NMR spectrum, δF, ppm: 89.3 d
(JFP 757 Hz). Found, %: C, 46.69; H 3.92; F 21.02; Se
14.47. C21H21O3Se·PF6. Calculated, %: C 46.24; H
3.85; F 20.90; Se 14.49.
Compound VIIc. Yield 53%, mp 60°C (ethanol).
9-Oxo-10-(4-heptyloxyphenyl)-9H-selenoxante-
nium hexafluorophosphate (IVa). Yield 75%, mp
66–68°C. IR spectrum, ν, cm–1: 2930, 2856 (C–H),
1
IR spectrum, ν, cm–1: 843, 557 (P–F). H NMR spec-
trum (300 MHz), δ, ppm: 3.86 s (9H, 3OMe), 7.09 d
3
3
(6H, HAr, JHH 9.0 Hz), 7.42 d (6H, HAr, JHH 9.0 Hz).
19F NMR spectrum, δF, ppm: 89.7 d (JFP 771 Hz).
Found, %: C, 45.59; H 3.92; F 21.09; Se 13.91.
C21H21O3Se·PF6. Calculated, %: C, 46.24; H 3.85; F
20.90; Se 14.52.
1
1668 (C=O), 841, 557 (P–F). H NMR spectrum, δ,
ppm: 0.86 m (3H, Me), 1.25 m (8H, 4CH2), 1.71 m
(2H, CH2), 3.92 m (2H, OCH2), 6.93 d and 7.49 d (4H,
3
С6Н4, JHH 8.8 Hz), 7.89 m (4H, H2,3,6,7), 8.00 m (2H,
19
H4,5), 8.61 m (2H, H1,8). F NMR spectrum, δF, ppm:
Spectral studies were performed at the Center for
Collective Usage, Siberian Branch, Russian Academy
of Sciences.
93.9 d (JFP 672 Hz). Found, %: C 52.49; H 4.50; F
18.79. C26H27O2Se·PF6. Calculated, %: C 52.44; H
4.54; F 19.16.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015

SYNTHESIS OF 9-OXOSELENOXANTHENIUM
1097
19. Jiricka, J., Kvis, F., and Borovicka, M., Czech Patent
121640, 1967, С. А. 1968, vol. 68, 114438h; Tsutomu, S.
and Seiki, F., Germany Patent DE 3209706, 1981, С. А.,
1983, vol. 98, 71934s.
REFERENCES
1. Sarker, A.M., Lungu, A., Mejiritski, A., Kaneko, Y.,
and Neckers D.C., J. Chem. Soc., Perkin Trans. 2, 1998,
p. 2315. DOI: 10.1039/A800469B.
20. Potash, S. and Rozen, S., Eur. J. Org. Chem., 2013,
p. 5574. DOI: 10.1002/ejoc.201.30000694.
2. Akhtar, S.R., Crivello, J.V., Lee, J.L., and Smitt, M.L.
Chem. Mater., 1990, vol. 2, p. 732. DOI: 10.1021/
cm00012a027.
21. Rheinboldt, H., Meth. Org. Chem. (Houben–Weyl),
vol. 9, p. 916.
3. Gomurashvili, Z. and Crivello, J.V., Macromolecules,
22. Mullica, D.F., Guziec, Jr. F.S., Guziec, L.J., Grant, J.R.,
Kantz, J.A., and Farmer, J.M., J. Mol. Struct., 1999,
vol. 478, p. 235. DOI: 10.1016/S0022-2860(98)00761-3.
2002, vol. 35, p. 2962. DOI: 10.1021/ma0119272.
4. Padon, K.S. and Scranton, A.B., Recent Res. Dev.
Polym. Sci., 1999, vol. 3, p. 369.
5. Crivello, J.V., J. Polymer Sci. (A), 1999, vol. 37,
p. 4241. DOI: 10.1002/(SICI)1099-0518(19991201)
37:23<4241::AID-POLA1>3.0.CO;2-R.
23. Crivello, J.V. and Lam, J.H.W., J. Org. Chem., 1978,
vol. 43, no. 15, p. 3055. DOI: 10.1021/jo00409a027.
24. Crivello, J.V. and Lam, J.H.W., J. Polymer Sci., 1979,
vol. 17, no. 4, p. 1047. DOI: 10.1002/pol.1979.170170410.
6. Crivello, J.V. and Lam, J.H.W., J. Polymer Sci. (A),
25. Wildi, B.S., Taylor, S.W., and Potratz, H.A., J. Am.
Chem. Soc., 1951, vol. 73, no. 5, p. 1965. DOI: 10.1021/
ja01149a017.
26. Ishii, Y., Iwama, Y., and Ogawa, M., Synth. Commun.,
1978, vol. 8, no. 2, p. 93. DOI: 10.1080/
00397917808062101.
27. Iwama, Y., Aragi, M., Sugiyama, M., Matsui, R., Ishii, Y.,
and Ogawa, M., Bull. Chem. Soc. Japan., 1981, vol. 54,
no. 7, p. 2065. DOI: 10.1246/bcsj.54.2065.
28. Ogawa, S., Sato, S., Masutomi, Y., and Furukawa, N.,
Phosphorus, Sulfur, Silicon, 1992, vol. 67, p. 99. DOI:
10.1080/ 10426509208045824.
1996, vol. 34, p. 3231. DOI:10.1002/pola.1996.873.
7. Kurze, A., Muller, U., Tittes, K., Fouassier, J.-P., and
Morlet-Savary, F., J. Photochem. Photobiol. (A), 1997,
vol. 110, p. 115. DOI: 10.1016/S1010-6030(97)00178-0.
8. Hyun, L.H., Patit, P., Kim, J.Y., and Kim, T.H., J. Appl.
Polymer Sci., 2007, vol. 103, p. 3157. DOI: 10.1002/
app.24749.
9. Yanez, C.O., Andrade, C.D., and Belfield, K.D., J. Royal
Soc. Chem. Chem. Commun., 2009, p. 827. DOI:
10.1039/b815831b.
10. Herlihy, S.L., WO 03 072567, C. A., 2003, vol. 139,
231972y.
29. Clivo, D.L.J. and Hua, Chong, Synth. Commun., 2003,
vol. 33, no. 11, p. 1951. DOI: 10.1081/SCC-12020210.
30. Lesser, R. and Weiss, R., Chem. Ber., 1912, vol. 45,
11. Herlihy, S.L., WO 03 072568, C. A., 2003, vol. 139,
231973z.
12. Davidson, R.S. and Pratt, J., WO 03 002557, C. A.,
2003, vol. 138, 91475r.
13. Taniguchi, N. and Yokoshima, M., Japan Patent 102
p. 1835.
31. Erben, F., Kleeblatt, D., Sonneck, M., Hein, M., Feist, H.,
Fahrenwaldt, Th., Fischer, Ch., Matin, A., Iqbal, J.,
Plotz, M., Tberle, J., and Langer, P., Org. Biomol.
Chem., 2013, vol. 11, p. 3963. DOI: 10.1039/c3ob40603b.
12286 (1998), C. A. 1998, vol. 129. 190509a.
14. Shelkovnikov, V.V., Loskutov, V.A., Vasil’ev, E.V.,
Shekleina, N.V., Ryabinin, V.A., and Sinyakov, A.N.,
Russ. Chem. Bull. Int. Eu., 2011, vol. 60, no. 3, p. 561.
DOI: 10.1007/s11172-011-0087-x.
15. Mac-Glinn, S., Adzumi, T., and Kinosita, M., Molecular
Spectroscopy of the Triplet State, Prentice-Hall, 1969.
Translated under the title Molekulyarnaya spektro-
skopiya tripletnogo sostoyaniya, Moscow: Mir, 1972,
p. 448; Louer, S. and El-Sied, M. E., Adv. Phys. Sc.,
1972, vol. 108, p. 103.
16. Excited States and Photochemistry of Organic Com-
pounds, Ulenikov, O.N., Ed., Novosibirsk: Nauka,
1997, p. 232.
17. Loskutov, V.A. and Shelkovnikov, V.V., Russ. J. Org.
Chem., 2006, vol. 42, no. 2, p. 298. DOI: 10.1134/
S107042800212028X.
32. Lesser, R. and Weiss, R., Chem. Ber., 1924, vol. 57.
p. 1077.
33. Kataoka, T., Tomimatsu, K., Shimazu, H., and Hori, M.,
Chem. Pharm. Bull., 1984, vol. 32, no. 7, p. 2666.
DOI: 10.1248/cpb.32.2666.
34. Syntheses of Organic Products, Kazanskii, B.A., Ed.,
Moscow: Izdatinlit, 1949, vol. 2, p. 237.
35. Keimatsu, S., Yokota, K., and Satoda I., J. Pharm. Soc.
Japan., 1933, vol. 53, p. 994.
36. Potapov, V.A., Khuriganova, O.I., and Amosova, S.V.,
Russ. J. Org. Chem., 2009, vol. 45, no. 10, p. 1569.
DOI: 10.1134/S107042800910025X.
37. Gould, E.S. and McCullough, J.D., J. Am. Chem. Soc.,
1951, vol. 73, no.7, p. 3196. DOI: 10.1021/ja01151a059.
38. Olah, G.A., Gupta, B.G.B., and Narang, S.C., J. Am.
Chem. Soc., 1979, vol. 101, no. 18, p. 5318. DOI:
10.1021/ja00512a034.
18. Loskutov, V.A. and Shelkovnikov, V.V., Russ. J. Org.
Chem., 2009, vol. 45, no. 1, p. 158. DOI: 10.1134/
S1070428009010230.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015