Electrochemical oxidative phosphorylation of azoles in the presence of silver catalysts

Article abstract of DOI:10.1007/s11172-018-2043-5

A new method for the phosphorylation of benzo-1,3-azoles (benzoxazole, benzothiazole, and 3-methylindole) with diethyl phosphite by electrocatalytic oxidation was proposed. The process occurs under electrochemical mild conditions (room temperature, normal pressure) in the presence of silver salts or silver oxide. This method allows one to obtain 2-phosphorylated products of benzo-1,3-azoles in good yield (up to 75%).

Full text of DOI:10.1007/s11172-018-2043-5

1
02
Russian Chemical Bulletin, International Edition, Vol. 67, No. 1, pp. 102—107, January, 2018
Electrochemical oxidative phosphorylation of azoles in the presence
of silver catalysts
E. O. Yurko, T. V. Gryaznova, V. V. Khrizanforova, M. N. Khrizanforov, A. V. Toropchina,
Yu. H. Budnikova, and O. G. Sinyashin
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of the Russian Academy of Sciences,
ul. Arbuzova, 420088 Kazan, Russian Federation.
8
Tel.: +7 (843) 279 5335. Eꢀmail: tatyanag@iopc.ru
A new method for the phosphorylation of benzoꢀ1,3ꢀazoles (benzoxazole, benzothiazole,
and 3ꢀmethylindole) with diethyl phosphite by electrocatalytic oxidation was proposed. The
process occurs under electrochemical mild conditions (room temperature, normal pressure)
in the presence of silver salts or silver oxide. This method allows one to obtain 2ꢀphosphorylꢀ
ated products of benzoꢀ1,3ꢀazoles in good yield (up to 75%).
Key words: СНꢀfunctionalization, phosphorylation, oxidation, electrosynthesis, catalyst,
benzoꢀ1,3ꢀazoles.
Benzoꢀ1,3ꢀazoles and their derivatives have unique
In the recent decade, serious efforts were focused on
the reactions of direct functionalization of the C(sp )—H
2
biological properties. For example, benzoxazoles exhibit
anticancer activity1 and are new nonꢀnucleoside inhibiꢀ
,2
bonds of azoles to form the 2ꢀsubstituted derivatives. They
were successfully arylated, alkylated, carboxylated, carbꢀ
onylated, and aminated.11 The method of direct catalytic
oxidative phosphorylation of aromatic azoles in the abꢀ
sence of bases and acids involving palladium salts as
3
tors of topoisomerase I. They can be considered as strucꢀ
tural bioisomers of natural nucleotides such as adenine
and guanine, which allow their easy reactions with polyꢀ
4
mers in living systems. Products for plant protection (for
example, insectoacaricide Zolon with contactꢀintestiꢀ
nal action (Sꢀ2,3ꢀdihydroꢀ(6ꢀchloroꢀ2ꢀoxybenzoxazolꢀ3ꢀ
a catalyst and excess K S O as an oxidant (Scheme 2)
2 2 8
has recently12 been described. The reaction at 100 °C
occurs slowly, and the yields of the С(2)ꢀphosphorylated
azole derivatives are 40—70%.
5
6
ylmethyl)ꢀО,Оꢀdiethyl dithiophosphate)), herbicides,
7
antidiabetics, and neuroleptics were prepared on the basis
of the benzoxazole derivatives. It has recently been found8
that 3ꢀphosphoindoles are good inhibitors of AIDSꢀ1.
Search for new lowꢀwaste routes of production of phosꢀ
phorusꢀcontaining derivatives of heterocycles, including
azoles, by direct phosphorylation of С—Н bonds is an
urgent trend.
Scheme 2
The phosphorylated derivatives of benzoxazoles have
first been synthesized as early as in the 1960s by A. I.
Razumov by heating orthoꢀaminophenol and diethyldiꢀ
9
,10
ethoxymethyl phosphonate with distillation of ethanol
Scheme 1).
(
Reagents: Pd(OAc)2 (5 mol.%), ligand (30 mol.%), K S O
8
2
2
Scheme 1
(
excess).
The crossꢀcoupling of 1Hꢀindole and diethyl phosꢀ
2
phites to form the C(sp )—P bond (Scheme 3) was deꢀ
scribed in 2012.13 Phosphorylated 1Hꢀindoles (16 comꢀ
pounds) were obtained in 18—71% yields and regioselecꢀ
tivity >15 : 1.
Later, urans, thiophenes, thioazoles, pyrroles, and pyꢀ
ridines were phosphorylated in the presence of catalytic
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 0102—0107, January, 2018.
066ꢀ5285/18/6701ꢀ0102 © 2018 Springer Science+Business Media, Inc.
1

Electrochemical phosphorylation of azoles
Russ.Chem.Bull., Int.Ed., Vol. 67, No. 1, January, 2018
103
Scheme 3
Scheme 6
(
2 equiv.)
Reagents and conditions: AgOAc (3 equiv.), ClCH CH Cl,
2
2
9
0 °C.
Scheme 4
R1 = H, 5ꢀCN; R2 = Me, Bu, Bn; R3 = Me, Et, Pri
Scheme 7
X = C, N, H; Y = O, S, NMe; R´ = Me, Et
Reagents and conditions: AgNO (0.2 equiv.), K S O (3 equiv.),
3
2
2
8
CH Cl , H O, 20 °C.
2
2
2
amounts of AgNO using K S O as an oxidant
3
2
2
8
1
4
(
Scheme 4). Dehydrocondensation between substituted
pyrroles and dialkyl phosphites occurs under similar conꢀ
1
5
ditions (Scheme 5).
Scheme 5
Reagents and conditions: i. AgCO3 (10 mol.%), Mg(NO3)2
(1.5 equiv.), MeCN, 80 °C, 24 h.
Reagents: HP(O)(OEt ) (3 equiv.), oxidant.
2
The regioselective crossꢀcoupling of Nꢀsubstituted inꢀ
doles with dialkyl phosphites is considered in the work1
published in 2016 (Scheme 6). The reaction was carried
pending on the nature of the oxidant (peroxide): derivaꢀ
tives of benzothiazoles, 2ꢀacylbenzothiazoles, and dialkylꢀ
benzothiazolꢀ2ꢀyl phosphonates (Scheme 8).
6
2
out in the presence of the Ru(bpy) (PF ) photoredox
The method of C(sp )—P bond formation was deꢀ
3
6 2
catalyst and oxygen as an oxidant. An intermediate phosꢀ
phorus radical cation is formed under the visible light
irradiation and then adds to the substrate to give 2ꢀinꢀ
scribed19 in 2016 via the crossꢀcoupling of the benzothiꢀ
azole derivatives with phosphorusꢀcontaining organic
compounds in the presence of threefold excess Mn(OAc)3
under the ballꢀmilling conditions (Scheme 9).
1
6
dolyl phosphonates in 70—82% yields.
The Agꢀcatalyzed phosphorylation of indoles substiꢀ
tuted at positions 2 and 3 in the presence of 1.5 equiv.
As a rule, a drawback of the above described reactions
is the necessity to use a large excess oxidant. The develꢀ
opment of more ecologically safe and simple catalytic
methods is especially urgent. Therefore, electrochemical
methods corresponding to criteria of green chemistry seem
to be attractive, since they are characterized by mild conꢀ
ditions of the process (low temperature, normal presꢀ
sure), the possibility of recovering the active form of the
catalyst at the electrode, as well as ecological safety and
Mg(NO ) as an oxidant was conducted later. The yield
3
2
of the 3ꢀphosphorylated derivatives from 2ꢀsubstituted
indoles is higher than that of the 2ꢀphosphorylated comꢀ
1
7
pounds from 3ꢀsubstituted indoles (Scheme 7).
1
8
In 2014, chinese scientists have found that various
products can be obtained by the reactions of benzothiꢀ
azoles and Hꢀphosphonates under mild conditions deꢀ

1
04
Russ.Chem.Bull., Int.Ed., Vol. 67, No. 1, January, 2018
Yurko et al.
Scheme 8
R1 = H, Me, OMe, Cl, Br, NO2
Reagents and conditions: i. TBHP, MeCN, 80 °C, 24 h; ii. DTBP, MeCN, 80 °C, 30 h.
Scheme 9
Electrolysis was carried out in a cell with divided
cathodic and anodic spaces. The silver salts (nitrate,
acetate, and carbonate) and silver oxide were tested as
catalysts. The electrolysis progress was monitored by
3
1
P NMR spectroscopy. The results of the electrolyses
are presented in Table 1.
Reagents and conditions: Mn(OAc) •2 H O (3 equiv.), ballꢀ
3
2
Low yields of phosphorylated benzothia(oxa)zoles
were observed (see Table 1, entries 1—4) when AgNO3
was used as the catalyst. An increase in the quantity of
electricity exerted no effect on the conversion of the iniꢀ
tial dialkyl phosphite, the signal of which is always deꢀ
tected in the spectrum of the reaction mixture, and on the
yield of the final product. Under these conditions, diisoꢀ
propyl phosphite turned out to be less reactive than diethyl
phosphite. The catalytic activity of silver acetate AgOAc
milling, 1.5 h, in air.
lowꢀwaste character. New electrochemical reactions of
2
C(sp )—H bond phosphorylation were proposed in the
recent years.2
0—27
The purpose of this work is the development of a new
method for the phosphorylation of the benzoꢀ1,3ꢀazole
derivatives with dialkyl phosphites under the conditions of
electrochemical oxidation in the presence of the silver salts.
turned out to be higher than that of AgNO . After passing
3
1
F electricity through the reaction mixture diethyl phosꢀ
3
1
Results and Discussion
phite : benzoxazole (1) : silver acetate = 1 : 1 : 0.1, the
P
NMR spectrum of the reaction mixture always contains
the signals of the initial diethylphosphorous acid at δ 8.90
(J = 688.3 Hz), the reaction product, phosphonate 3, at
δ –0.33, and the protonated form of the reaction prodꢀ
uct А at δ 2.81 (J = 566.29 Hz). Only after passing 3 F
electricity through the reaction mixture, the signal of the
initial acid disappears, and only signals of two reaction
The joint electrolysis of a mixture of benzoxazole (1)
or benzothiazole (2)) and dialkyl phosphites under the
oxidation conditions in the presence of catalytic amounts
of the silver salts at room temperature affords 2ꢀphosꢀ
phorylated benzothia(oxa)zoles, dialkylbenzothia(oxa)ꢀ
zolꢀ2ꢀyl phosphonates 3—6 (Scheme 10).
(
Scheme 10
*
The amount of passed electricity was 1.5 times higher than the theoretical value.
X = O (1), S (2)
R = Et, X = O (3), S (4); R = Pr , X = O (5), X = S (6)
i

Electrochemical phosphorylation of azoles
Russ.Chem.Bull., Int.Ed., Vol. 67, No. 1, January, 2018
105
Table 1. Results of the electrochemical phosphorylation of benzoxazole (1) and benzothiazole (2) with diethyl phosphite in MeCN
Entry
Azole
Catalyst
Base
Potential
Product
Yield of product (%)
of anode/V
Substance
Current
1
2
3
4
5
1
1
2
2
1
AgNO3
AgNO3*
AgNO3
AgNO3*
AgOAc
—
—
—
—
2.14
1.75
1.73
1.70
2.22
3
5
4
6
3
41
30
42
45
61
26
19
26.5
26.5
39
Treatment with
t
Bu OK
after electrolysis
6
7
8
9
1
1
1
1
1
1
2
2
1
1
AgOAc
AgOAc
AgOAc
AgOAc
AgOAc
K CO
2.08
2.16
2.22
2.17
2.12
2.00
1.28
3
3
3
4
4
3
3
63
75
63
51
54
18
34
40.5
48
40.5
32.5
34.5
5
2
3
Na PO
3
4
NaH PO
2
3
3
Na PO
3
4
0
1
2
NaH PO
2
Ag CO
—
—
2
3
Ag O
22.5
2
*
Phosphorylation with diisopropyl phosphite.
products are observed in the spectrum, i.e., final phosꢀ
phonate 3 and its protonated form А, which is always
present due to strong acidification of the reaction mixture
during oxidation processes. The reaction mixture was
treated with a base to obtain the pure product. Potassium
tertꢀbutylate and triethylamine were tested as bases. It
turned out that only after the treatment of the reaction
pounds, because the indole derivatives have unique bioꢀ
logical properties. It turned out that compound 7 is phosꢀ
phorylated under the chosen conditions to form phosꢀ
phorylated derivative 8 in 30—50% yields (Scheme 11,
Table 2). As in the case of benzoꢀ1,3ꢀazoles, silver acetate
turned out to be the best catalyst.
t
mixture with Bu OK, the protonated form of the product А
converts completely to phosphonate 3 (entry 5). Elecꢀ
Scheme 11
trolysis in the presence of a base (K CO , Na PO , and
2
3
3
4
NaH PO were tested) made it possible to obtain the
2
3
final product avoiding formation of the protonated speꢀ
cies. Under these conditions, benzothiazole (2) is also
phosphorylated to form 2ꢀsubstituted derivative 4 (δ 2.19)
Р
(
entries 9 and 10). The use of silver carbonate Ag CO in
2 3
the electrochemical phosphorylation of benzoꢀ1,3ꢀazole
1) also results in the formation of 2ꢀsubstituted derivaꢀ
(
tive 3, although in a low yield (entry 11). It is most likely
that the electrolysis leads to the formation of unstable
carbonic acid that readily decomposes to СО and Н О,
2
2
resulting in the decomposition of silver carbonate that
equimolarly reacts with benzoxazole (1) and diethyl phosꢀ
phite. Under the electrochemical conditions, excess diꢀ
ethyl phosphite is oxidized to tetraethyl pyrophosphate
*
The amount of passed electricity was 1.5 times higher
than the theoretical value.
Thus, the convenient preparative method of electroꢀ
synthesis of 2ꢀphosphorylated benzoꢀ1,3ꢀazoles was deꢀ
veloped using the silver salts as catalysts. The electrolysis
proceeds via one step at room temperature. Silver acetate
turned out to be the best catalyst for this process of the
salts studied.
(
δ –12). Silver oxide Ag O was also tested as a catalyst
Р 2
in the same reaction (entry 12). After passing 3 F elecꢀ
tricity, the spectrum of the reaction mixture contains sigꢀ
nals of both the product and initial diethylphosphorous
acid. The yield of the final 2ꢀphosphorylated benzoxazole
3
was 34%. Thus, the highest yields (75%) were achieved
when silver acetate was used as the catalyst and Na PO
Experimental
3
4
served as the base (entry 7).
3
ꢀMethylindole (7) was also studied as a substrate in
Acetonitrile was distilled over Р О and KMnO and then
2
5
4
the electrochemical phosphorylation of heterocyclic comꢀ
over molecular sieves. Benzene was distilled over sodium metal.

1
06
Russ.Chem.Bull., Int.Ed., Vol. 67, No. 1, January, 2018
Yurko et al.
Table 2. Results of the electrolytic phosphorylation of 3ꢀmethylindole with diethyl phosphite in MeCN
Entry
Catalyst
Base
Oxidation potential/V
Yield of product (%)
Substance
Current
1
2
3
AgNO3
AgOAc
Na PO
1.84
2.03
1.32
41
50
31
40
26.5
20
3
4
4
4
Na PO
3
Ag O
Na PO
3
2
After purification, the solvents were stored under a dry argon
atmosphere. Benzoxazole, benzothiazole, 3ꢀmethylindole, silꢀ
ver acetate, silver carbonate, silver oxide (all from Alfa Aesar),
diethyl phosphite, and diisopropyl phosphite (Acros Organics)
were used. All syntheses were carried out under a dry argon
atmosphere. Preparative electrolyses were conducted using
a B5ꢀ49 dc source in a threeꢀelectrode 30ꢀmL cell. The potenꢀ
tial of the working electrode was detected with a V7ꢀ27 dc
voltmeter relative to the reference electrode Ag/0.01 М AgNO3
in acetonitrile. The working surface of the platinum cylindrical
4.11 (dq, 4 H, J = 6.9 Hz, J = 9.2 Hz); 1.31 (t, 6 H, J = 6.9 Hz).
3
1
P NMR ((CD ) CO), δ: 4.79 (s). MS (ESI), m/z: 272.1
3
2
+
[M + H] .
Diisopropylbenzothiazolꢀ2ꢀyl phosphonate (5), yellow
oil.12 1Н NMR (CDСl ), δ: 7.79 (d, 1 H, J = 6.9 Hz); 7.59 (d, 1 H,
3
J = 7.14 Hz); 7.38 (m, 2 H); 4.72 (m, 2 H); 1.36 and 1.35 (both
3
1
d, 12 H, J = 6.17 and J = 6.18 Hz). P NMR (CDCl ), δ:
3
+
–2.59 (s). MS (ESI), m/z: 284.2 [M + H] .
Diisopropylbenzoxazolꢀ2ꢀyl phosphonate (6), yellow oil.12
1
Н NMR (CDСl ), δ: 8.13 (d, 1 H, J = 8.18 Hz); 7.94 (d, 1 H,
3
2
cathode used as a working electrode was 20.0 cm . A ceramic
plate with a pore size of 900 nm served as a membrane.
A platinum grid served as an anode, and a saturated solution of
J = 8.00 Hz); 7.50 (t, 1 H, J = 7.10 Hz); 7.90 (t, 1 H,
J = 7.19 Hz); 4.43 (m, 2 H); 1.24 and 1.23 (both d, 12 H,
3
1
J = 6.17 Hz, J = 6.17 Hz). P NMR (CDCl ), δ: 1.24 (s). MS
3
+
PyHBF in acetonitrile was used as a catholyte. During elecꢀ
(ESI), m/z: 300.4 [M + H] .
4
Diethylꢀ3ꢀmethylꢀ1Hꢀindolꢀ2ꢀyl phosphonate (8),1
3,15
trolysis, the electrolyte was magnetically stirred under a conꢀ
tinuous argon flow, which was passed through the drying sysꢀ
tem. NMR spectra were recorded on a Bruker AVANCEꢀ400
1
light yellow oil, m.p. 103 °C. Н NMR (CDСl ), δ: 8.06 (br.s,
3
1 H); 7.71 (d, 1 H, J = 7.06 Hz); 7.54 (t, 1 H, J = 8.22 Hz); 7.03
(d, 1 H, J = 8.29 Hz); 6.91 (t, 1 H, J = 7.42 Hz); 4.74 (dq, 4 H,
1
31
multinuclear spectrometer (400.1 ( Н) and 162.0 MHz ( Р)).
Chemical shifts were detected relative to the signals of the deuꢀ
J = 7.1 Hz, J = 8.8 Hz); 2.30 (s, 3 Н); 1.42 (t, 6 H, J = 7.0 Hz).
1
31
31
terated solvent ( Н) and phosphoric acid ( Р) as internal stanꢀ
dards. Electrospray ionization (ESI) mass spectra were obtained
on an AmazonX spectrometer (Bruker Daltonik GmbH, Gerꢀ
many) in the positive mode with a capillary voltage of 4500 V.
Electrolysis (general procedure). Silver salt (0.42 mmol),
benzothia(oxa)zole (4.2 mmol), and dialkylphosphorous acid
P NMR (CDCl ), δ: 10.008 (s). MS (ESI), m/z: 268.2
3
+
[M + H] .
This work was financially supported by the Russian
Science Foundation (Project No. 14ꢀ23ꢀ00016).
(
4.2 mmol) in acetonitrile (30 mL) were placed in an electroꢀ
References
chemical cell. Electrolysis was carried out in the galvanostatic
mode with the simultaneous control of the working electrode
potential in the cell with divided anodic and cathodic spaces
with magnetic stirring and continuous argon flow. A saturated
1. D. Kumar, M. R. Jacob, M. B. Reynolds, S. M. Kerwin,
Bioorg. Med. Chem., 2002, 10, 3997.
solution of PyHBF in acetonitrile was placed in the cathodic
2. S. M. Rida, F. A. Ashour, S. A. M. ElꢀHawash, M. M. Elꢀ
Semary, M. H. Badr, M. A. Shalaby, Eur. J. Med. Chem.,
2005, 40, 949.
3. J. S. Kim, Q. Sun, B. Gatto, C. Yu, A. Liu, L. F. Liu, E. J.
LaVoie, Bioorg. Med. Chem., 1996, 4, 621.
4
space. Electricity (3 F, 350 mA h) was passed through the elecꢀ
trolyte. After complition of electrolysis, the reaction mixture was
concentrated on a rotary evaporator. The residue was treated
t
with an equimolar amount of Bu OK (this step was omitted
when the electrolysis was carried out in the presence of a base),
washed with an aqueous solution of ammonium chloride, and
extracted with benzene (3×40 mL). After separation, the orꢀ
4. D. W. Dunwell, D. J. Evans, Med. Chem., 1977, 20, 797.
5. N. N. Mel´nikov, K. V. Novozhilov, S. P. Belan, Pestitsidy i
regulyatory rosta rastenii [Pesticides and Regulators of Plant
Growth], Moscow, Khimiya, 1995, 576 (in Russian).
6. J. Suzuki, K. Takahashi, S. Fukuda, Pat. US, 2008/058213.
7. S. Schunk, M. Rich, M. Engels, T. Germann, J. De Vry,
R. Jostock, S. Hers, Pat. WO 2010/142402.
ganic layer was dried for 24 h over MgSO and the solvent was
4
evaporated. The residue was purified by column chromatoꢀ
graphy on silica gel (elution with hexane—ethyl acetate).
Diethylbenzoxazolꢀ2ꢀyl phosphonate (3),12 yellow oil.
1
Н NMR (CDСl ), δ: 7.45 (d, 1 H, J = 7.9 Hz); 7.09 (t, 1 H,
8. R. Storer, C. Dousson, F.ꢀR. Alexandre, A. Roland, Pat. EP
1961757 A1, 2008.
3
J = 7.2 Hz); 7.02 (d, 1 H, J = 8.1 Hz); 6.24 (t, 1 H, J = 8.0 Hz);
4
.14 (dq, 4 H, J = 7.1 Hz, J = 8.6 Hz); 1.36 (t, 6 H, J = 7.0 Hz).
9. A. I. Razumov, B. G. Liorber, P. A. Gurevich, Zh. Obshch.
Khim., 1967, 37, 2782 (in Russian).
10. A. I. Razumov, P. A. Gurevich, B. G. Liorber, T. D. Borisoꢀ
va, Zh. Obshch. Khim., 1969, 39, 392 (in Russian).
11. J. Maes, B. U. W. Maes, Adv. Heterocycl. Chem., 2016, 120,
138—188.
3
1
P NMR (CDCl ), δ: –1.14 (s). MS (ESI), m/z: 256.05
3
+
[
M + H] .
Diethylbenzoxazolꢀ2ꢀyl phosphonate (4),12 yellow oil.
1
Н NMR ((CD ) CO), δ: 8.30 (d, 1 H, J = 7.5 Hz); 8.23 (d, 1 H,
3
2
J = 7.7 Hz); 7.73 (t, 1 H, J = 7.1 Hz); 7.66 (t, 1 H, J = 8.1 Hz),

Electrochemical phosphorylation of azoles
Russ.Chem.Bull., Int.Ed., Vol. 67, No. 1, January, 2018
107
1
2. Ch. Hou, Y. Ren, R. Lang, X. Hu, Ch. Xia, F. Li, Chem.
Commun., 2012, 48, 5181.
3. H. Wang, X. Li, F. Wu, B. Wan, Synthesis, 2012, 44, 941.
4. C.ꢀB. Xiang, Y.ꢀJ. Bian, X.ꢀR. Mao, Z.ꢀZ. Huang, J. Org.
Chem., 2012, 77, 7706.
22. Yu. H. Budnikova, Sovremennyi organicheskii elektrosintez
[Modern Organic Electrosynthesis], Moscow, IFRAꢀM, 2016,
440 pp. (in Russian).
23. Yu. H. Budnikova, O. G. Sinyashin, Russ. Chem. Rev., 2015,
84, 917.
1
1
1
1
1
1
5. S. H. Kim, K. H. Kim, J. W. Lim, J. N. Kim, Tetrahedron
Lett., 2014, 531.
6. Z. Mina, W. Donga, Z. Penga, D. An, Synth. Commun.,
24. S. O. Strekalova, M. N. Khrizanforov, T. V. Gryaznova,
V. V. Khrizanforova, Yu. H. Budnikova, Russ. Chem. Bull.,
2016, 65, 1295.
25. M. N. Khrizanforov, S. O. Strekalova, K. V. Kholin, V. V.
Khrizanforova, M. K. Kadirov, T. V. Gryaznova, Yu. H.
Budnikova, Catal. Today, 2017, 279, 133.
26. Yu. H. Budnikova, T. V. Gryaznova, V. V. Grinenko, Y. B.
Dudkina, M. N. Khrizanforov, Pure Appl. Chem., 2017,
89, 311.
2
016, 46, 128.
7. W.ꢀB. Sun, J.ꢀF. Xue, G.ꢀY. Zhang, R.ꢀS. Zeng, L.ꢀT. An,
P.ꢀZ. Zhang, J.ꢀP. Zoua, Adv. Synth. Catal., 2016, 358, 1753.
8. X.ꢀL. Chen, X. Li, L.ꢀB. Qu, Y.ꢀC. Tang, W.ꢀP. Mai, D.ꢀH.
Wei, W.ꢀZ. Bi, L.ꢀK. Duan, K. Sun, J.ꢀY. Chen, D.ꢀD. Ke,
Y.ꢀF. Zhao, J. Org. Chem., 2014, 79, 8407.
1
2
9. L. Li, J.ꢀJ. Wang, G.ꢀW. Wang, J. Org. Chem., 2016, 81, 5433.
0. T. V. Gryaznova, Y. B. Dudkina, D. R. Islamov, O. N. Kaꢀ
taeva, O. G. Sinyashin, D. A. Vicic, Yu. H. Budnikova,
J. Organomet. Chem., 2015, 785, 68.
27. T. Gryaznova, Yu. Dudkina, M. Khrizanforov, O. Sinyashꢀ
in, O. Kataeva, Yu. Budnikova, J. Solid State Electrochem.,
2015, 19, 2665.
2
1. Yu. B. Dudkina, T. V. Gryaznova, O. N. Kataeva, Yu. H.
Budnikova, O. G. Sinyashin, Russ. Chem. Bull., 2014,
Received June 30, 2017;
in revised form October 20, 2017;
accepted October 26, 2017
6
3, 2641.