1-methyl-2-(1'-methyl-2'-pyrrolyl)-1H-phenanthro[9,10-d]-imidazole. Synthesis and electrophilic substitution reactions

Article abstract of DOI:10.1134/S1070363211080238

2-(1'-Methyl-2'-pyrrolyl)-1H-phenanthro[9,10-d]imidazole was synthesized by heating 9,10- phenanthrenequinone and 1-methyl-2-pyrrolecarboxaldehyde in glacial acetic acid in the presence of ammonium acetate. The reactions of electrophilic substitution (nit

Full text of DOI:10.1134/S1070363211080238

ISSN 1070-3632, Russian Journal of General Chemistry, 2011, Vol. 81, No. 8, pp. 1720–1725. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © G.V. Salamatina, A.A. Aleksandrov, M.M. El’chaninov, 2011, published in Zhurnal Obshchei Khimii, 2011, Vol. 81, No. 8,
pp. 1376–1381.
1-Methyl-2-(1'-methyl-2'-pyrrolyl)-1H-phenanthro[9,10-d]-
imidazole. Synthesis and Electrophilic Substitution Reactions
G. V. Salamatina, A. A. Aleksandrov, and M. M. El’chaninov
Southern Russian State Technical University, ul. Prosveshcheniya 132, Novocherkassk, 346428 Russia
e-mail: aaanet1@yandex.ru
Received June 24, 2010
Abstract—2-(1'-Methyl-2'-pyrrolyl)-1H-phenanthro[9,10-d]imidazole was synthesized by heating 9,10-
phenanthrenequinone and 1-methyl-2-pyrrolecarboxaldehyde in glacial acetic acid in the presence of
ammonium acetate. The reactions of electrophilic substitution (nitration, bromination, sulfonation, formylation,
acylation) were studied for the product of its N-methylation in the KOH–DMSO medium. The electrophilic
attack was found to affect exclusively the pyrrole ring.
DOI: 10.1134/S1070363211080238
In extention of the search for new biologically
active compounds and luminophores in a series of
fused derivatives of 2-hetarylimidazoles, we set a goal
to develop or find a convenient synthesis method, to
study the relative reactivity of 1-methyl-2-(1'-methyl-
2'-pyrrolyl)-1H-phenanthro[9,10-d]imidazole Ia, and
to compare it with the benzimidazole analog II.
amount of methyl iodide to produce the target product
in high yield [5]. The product Ia was subjected to the
action of electrophilic reagents like acetyl nitrate, bro-
mine in dichloroethane, pyridine sulfotrioxide in
dichloroethane, the Vilsmeier reagent, urotropine in
polyphosphoric acid, acetic anhydride in the presence
of perchloric acid, benzoic acid in polyphosphoric acid.
N
N
N
N
N
N
N
N
H
N
Me
Me
Me
Me
Me
Ia
II
I
It was shown earlier [1] that in contrast to other
methods [2, 3] the synthesis of 2-(2'-furyl)-1H-and 2-
(2'-thienyl)-1H-phenanthro[9,10-d]imidazole gives the
best results in the case of condensation of 9,10-phen-
antrenequinone and the corresponding aldehydes in the
presence of ammonium acetate in glacial acetic acid
[4]. Our studies confirm that the method of Steck and
Day is also appropriate to produce 2-(1'-methyl-2'-
pyrrolyl)-1H-phenanthro[9,10-d]imidazole I, but n-
propanol should be used instead of acetic acid due to
the high acidophobicity of 1-methyl-2-pyrrolecarbox-
aldehyde. The yield of I does not exceed 60%.
MeI
N
KOH/DMSO
N
N
Me
Me
Ia
In previous studies [6, 7] we have shown that
various systems of 2-hetarylimidazoles stabilize in
their composition five-membered π-excessive hetero-
cycles. Obviously, this is due to the electron-
withdrawing nature of the 2-imidazolyl moiety, which
increases at the protonation. It was of interest to
The methylation reaction of compound I was
carried out in a KOH–DMSO system using equivalent
1720

1-METHYL-2-(1'-METHYL-2'-PYRROLYL)-1H-PHENANTHRO[9,10-d]-IMIDAZOLE
1721
determine the degree of electron-withdrawing effect of
acceptor properties of the phenanthro[9,10-d]imidazol-
2-yl group are relatively low. This is due to the low
aromaticity of the central benzene ring of the
phenanthrene system that reduces its electron-
withdrawing effect. In this connection we should
expect a higher reactivity of the pyrrole ring in
compound Ia.
phenanthro[9,10-d]imidazol-2-yl and benzimidazol-2-
1
yl groups on the pyrrole ring on the basis of the H
NMR spectroscopy. Analysis of the downfield shifts of
the pyrrole protons H3 of compounds Ia (6.53 ppm)
and II (6.68 ppm) caused primarily by the electron-
withdrawing effect clearly indicates that the electron-
Cu(NO3)2
Ac2O
NO2
N
Me
Ib
Br2
Br
1,2-Dichloroethane
Br
N
Me
Ic
C5H5N SO3
SO3H
N
1,2-Dichloroethane
Me
Id
DMF_POCl3
N
CHO
+
CHO
N
N
N
N
Me
Me
Me
Me
If
Ie
Ia
COMe
COPh
Ac2O/HClO4
+
+
COMe
COPh
N
N
Me
Ih
Me
Ig
PhCOOH
polyphosphoric acid
N
N
Me
Me
Ij
Ii
(СH2)6N4
CH2
polyphosphoric acid
N
N
Me
Me
Ik
The reactions performed confirm this assump-
tion. The yields and physicochemical constants of the
compounds obtained are given in Table 1.
in acetic anhydride at 0°C of the β-position of the
pyrrole ring. Under these conditions the similar
reaction of compound Ia proceeds nonselectively due
to its high reactivity with respect to acetyl
nitrate. Therefore in this case we used the method of
thiophenes nitration [8] by a combination of copper
The nitration of compound II have been shown [7]
to occur at the action of a fuming nitric acid (d 1.5 g cm–3)
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 8 2011

1722
SALAMATINA et al.
Table 1. Yields, melting points and elemental analysis data for compounds I
Found, %
Calculated, %
H
Comp. Yield,
mp, °С
Formula
no.
%
С
Н
N
C
N
60
64
84
87
46
65
17
69
12
42
12
44
131–132
149–150
273–274
272–273
258–259
227–228
215–216
198–199
206–207
144–145
151–152
175–176
80.93
81.23
71.03
53.87
64.78
78.12
77.68
77.93
78.44
81.27
81.15
81.25
4.88
5.37
4.22
3.49
4.12
4.88
5.17
5.62
5.75
5.17
4.88
5.53
13.91
13.17
15.95
9.14
C20H15N3
80.78
81.00
70.78
53.76
64.44
77.86
77.86
78.16
78.16
80.94
80.94
81.36
5.05
5.50
4.53
3.22
4.38
5.05
5.05
5.42
5.42
5.09
5.09
5.40
14.13
13.49
15.72
8.96
I
C21H17N3
Iа
Ib
Ic
Id
Ie
If
C21H16N4O2
C21H15Br2N3
C21H17N3O3S
C22H17N3O
C22H17N3O
C23H19N3O
C23H19N3O
C28H21N3O
C28H21N3O
C43H34N6
10.55
12.49
12.66
12.11
11.64
9.88
10.73
12.38
12.38
11.89
11.89
10.11
10.11
13.24
Ig
Ih
Ii
Ij
10.37
13.10
Ik
nitrate and acetic anhydride. In contrast to compound
II, the substitution in this case occurs at the position 5’
of the pyrrole ring to give Ib in yield of 84%.
tively. Obviously, the formation of aldehyde If indi-
cates a decrease in the electron-withdrawing effect of
phenanthro[9,10-d]imidazole moiety on the pyrrole
ring in comparison with benzimidazole.
The bromination of compound Ia was carried out
by the action of bromine in dichloroethane at
–10°C. According to the H NMR spectrum under
Previously, for the formylation of furyl- and
thienylphenantro[9,10-d]imidazoles hexamethylene-
tetramine in polyphosphoric acid medium was used
[9]. We attempted to apply this method to compound
Ia. As a result, as in the case of pyrrolylbenzimidazole
II, dipyrrolylmethane derivative Il was formed in 47%
yield.
1
these conditions the formation of 4',5'-dibromo-
derivative Ic actually occurs. A characteristic signal of
the spectrum is a singlet of the proton 3'CH at
6.75 ppm (Table 2). A similar transformation of
compound II takes place in acetic acid at 20°C.
According to [7], 2-(1'-methyl-2'-pyrrolyl)benzimida-
zole II is sulfonated with sulfuric acid (d 1.84 g cm–3)
in acetic anhydride on the 4'-position of pyrrole
moiety. The compound Ia is tarred in such rigid
conditions. Therefore it was sulfonated with pyridine
sulfotrioxide in the boiling dichloroethane to give 5'-
sulfonic acid Id in a yield of 46%. The difference in
the direction of sulfonation of compounds II and Ia
with sulfuric acid and pyridine sulfotrioxide is
obviously due to the fact that in the first case reacts the
benzimidazole cation, while in the second case reacts
the neutral form of the substrate.
According to [10], the acetylation of compound II
with a mixture of acetic and polyphosphoric acid at
110°C occurs at the position 4' of the pyrrole. We
succeeded in acetylating compound Ia by heating in
acetic anhydride in the presence of catalytic amounts
of perchloric acid, i. e., in mild conditions of the
Dorofeenko reaction. Like the formylation, the
acylation proceeds with the formation of a mixture of
4'- and 5'-acetyl derivatives Ig and Ih in 75%
yield. Both isomers are easily separated by the column
1
chromatography. In their H NMR spectra the signals
of pyrrole protons appear at 7.00 and 7.50 ppm (J3,5
1.4 Hz) (Ig) and at 6.62 and 7.08 ppm (J3, 4 4.0 Hz)
(Ih). The coupling constants values indicate clearly the
4'- and 5'-substitution of the pyrrole ring.
The study of the formylation of compound Ia with
the Vilsmeier reagent gave the unexpected result. Unlike
pyrrolylbenzimidazole II, which gives under these
conditions exclusively 4'-formyl pyrrole derivative,
compound Ia is formylated not only in the position 4',
but also in the position 5'. The yield of isomeric
aldehydes Ie and If is 65 and 17%, respec-
The direction of the benzoylation of compound II
in polyphosphoric acid at 140–150°C is not different
from that of the acetylation of the same sub-
strate. Compound Ia is benzoylated most smoothly. In
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1-METHYL-2-(1'-METHYL-2'-PYRROLYL)-1H-PHENANTHRO[9,10-d]-IMIDAZOLE
Table 2. The IR and 1Н NMR (СDCl3)a spectral data for compounds Iа–Il
1723
Comp.
no.
IR spectrum
ν, сm–1
1Н NMR spectrim (СDCl3)a, δ, ppm
–
3.95 s (3H, NCH3), 4.35 s (3H, NCH3), 6.28 d (1Н, СНHt, J 3.2 Hz), 6.54 d (1Н, СНHt, J 3.2 Hz), 7.60 m (4Н,
СНAr), 7.86 d (1Н, СНHt, J 2.1 Hz), 8.50 d (1Н, СНHt, J 8.2 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н,
СНAr, J 8.0 Hz), 8.82 d (1Н, СНAr, J 7.7 Hz)
Iа
1360 sym. (NO2) 4.15 s (3H, NCH3), 4.28 s (3H, NCH3), 6.54 d (1Н, СНHt, J 4.0 Hz), 7.38 d (1Н, СНHt, J 4.0 Hz), 7.65 m (4Н,
1545 assym. (NO2) СНAr), 8.45 d (1Н, СНAr, J 8.2 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.70 d (1Н, СНAr, J 8.0 Hz), 8.82 d (1Н,
СНAr, J 7.7 Hz)
Ib
Ica
–
3.60 s (3H, NCH3), 4.20 s (3H, NCH3), 6.75 d (1Н, СНHt), 7.70 m (4Н, СНAr), 8.53 d (1Н, СНAr, J 7.7 Hz),
8.65 d (1Н, СНAr, J 8.2 Hz), 8.82 d (1Н, СНAr, J 8.0 Hz), 8.92 d (1Н, СНAr, J 7.7 Hz)
4.05 s (3H, NCH3), 4.40 s (3H, NCH3), 6.45 d (1Н, СНHt, J 4.1Hz), 7.32 d (1Н, СНHt, J 4.1 Hz), 7.60 m (4Н,
СНAr), 8.42 d (1Н, СНAr, J 8.2 Hz), 8.63 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr, J 7.8 Hz), 8.84 d (1Н,
СНAr, J 7.7 Hz)
Idb
1260 (SO2)
1660 (C=O)
1680 (C=O)
1660 (C=O)
1670 (C=O)
1650 (C=O)
1660 (C=O)
–
4.05 s (3H, NCH3), 4.32 s (3H, NCH3), 7.00 d (1Н, СНHt, J 1.5 Hz), 7.51 d (1Н, СНHt, J 1.5 Hz), 7.65 m (4Н,
СНAr), 8.50 d (1Н, СНAr, J 8.2 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr, J 8.0 Hz), 8.82 d (1Н,
СНAr, J 7.7 Hz), 9.83 s (1Н, CHO)
Ie
If
4.16 s (3H, NCH3), 4.30 s (3H, NCH3), 6.62 d (1Н, СНHt, J 4.1 Hz), 7.08 d (1Н, СНHt, J 4.1 Hz), 7.68 m (4Н,
СНAr), 8.55 d (1Н, СНAr, J 8.0 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr, J 8.0 Hz), 8.82 d (1Н,
СНAr, J 7.7 Hz), 9.70 s (1Н, СНO)
2.65 s (3H, CH3), 4.05 s (3H, NCH3),4.32 s (3H, NCH3), 7.00 d (1Н, СНHt, J 1.4 Hz), 7.50 d (1Н, СНHt,
J 1.4 Hz), 7.64 m (4Н, СНAr), 8.50 d (1Н, СНAr, J 8.2 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr,
J 8.0 Hz), 8.80 d (1Н, СНAr, J 7.7 Hz)
Ig
Ih
Ii
2.53 s (3H, CH3), 4.16 s (3H, NCH3), 4.33 s (3H, NCH3), 6.62 d (1Н, СНHt, J 4.0 Hz), 7.08 d (1Н, СНHt,
J 4.0 Hz), 7.68 m (4Н, СНAr), 8.55 d (1Н, СНAr, J 8.2 Hz), 8.68 d (1Н, СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr,
J 8.0 Hz), 8.85 d (1Н, СНAr, J 7.7 Hz)
4.02 s (3H, NCH3), 4.28 s (3H, NCH3), 6.96 d (1Н, СНHt, J 1.2 Hz), 7.48 d (1Н, СНHt, J 1.2 Hz), 7.53 t (3H,
CHAr, J 7.5 Hz), 7.65 m (4Н, СНAr), 7.91 d (2Н, СНAr, J 7.2 Hz), 8.50 d (1Н, СНAr, J 8.2 Hz), 8.68 d (1Н,
СНAr, J 7.7 Hz), 8.75 d (1Н, СНAr, J 8.0 Hz), 8.84 d (1Н, СНAr, J 7.7 Hz)
4.10 s (3H, NCH3), 4.30 s (3H, NCH3), 6.60 d (1Н, СНHt, J 4.0 Hz), 7.10 d (1Н, СНHt, J 4.0 Hz), 7.48 t (3H,
CHAr, J 7.5 Hz), 7.63 m (4Н, СНAr), 7.88 d (2Н, СНAr, J 7.2 Hz), 8.48 d (1Н, СНAr, J 8.0 Hz), 8.65 d (1Н,
СНAr, J 7.7 Hz), 8.72 d (1Н, СНAr, J 8.0 Hz), 8.82 d (1Н, СНAr, J 7.7 Hz)
Ij
3.98 s (6H, 2NCH3), 4.33 s (6H, 2NCH3), 4.40 s (2H, CH2), 6.47 d (2Н, СНHt, J 1.5 Hz),7.60 m (8Н, СНAr),
7.75 d (2Н, СНHt, J 1.5 Hz), 8.48 d (2Н, СНAr, J 8.2 Hz), 8.68 d (2Н, СНAr, J 7.7 Hz), 8.72 d (2Н, СНAr,
J 8.0 Hz), 8.80 d (2Н, СНAr, J 7.7 Hz)
Ik
a The 1H NMR spectrum was recorded in DMSO-d6 + CCl4. b The 1H NMR spectrum was recorded in DMSO-d6.
the above conditions, after 1 h heating, a mixture of 4'-
(Ii) and 5'-benzoyl derivatives (Ik) was obtained in 42
and 12% yields respectively.
activity detecting with iodine vapor (eluents CH2Cl2,
CHCl3). The elemental analysis was performed on a
Perkin Elmer 2400 analyzer. Melting points were
determined by capillary method.
EXPERIMENTAL
2-(1'-Methyl-2'-pyrrolyl)-1H-phenanthro[9,10-d]
imidazole (I). To a boiling solution of 4.10 g
(0.05 mol) of 9,10-phenanthrenequinone in 300 ml of
n-propanol 7.7 g (0.1 mol) of ammonium acetate and
6.54 g (0.06 M.) of 1-methyl-2-pyrrolecarboxaldehyde
in 50 ml of n-propanol was added. The mixture was
refluxed for 2 h and kept at room temperature for
The IR spectra were recorded on a Specord 75 IR
spectrophotometer from the mulls in mineral oil. The
1H NMR spectra were recorded on a Varian Unity 300
instrument (300 MHz, CDCl3) with internal reference
TMS. The reaction was monitored by TLC on the
plates covered with Al2O3 of II degree of Brockmann
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 8 2011

1724
SALAMATINA et al.
2–3 h. The precipitate formed was filtered off and
washed with 50 ml of alcohol. The filtrate was diluted
with 200 ml of cold water and neutralized with
ammonia solution to pH 8–9. The precipitate was
separated, dried, and recrystallized from alcohol. The
yield, melting point, elemental analysis data of I are
shown in Table. 1.
25% solution of ammonia. Compound Ib was crystal-
lized from alcohol.
1-Methyl-2-(1'-methyl-5'-sulfo-2'-pyrrolyl)-1H-
phenanthro[9,10-d]imidazole (Id). A mixture of 1.56 g
(0.005 mol) of compound Ia and 1.6 g (0.01 mol) of
pyridine sulfotrioxide in 25 ml of dichloroethane was
refluxed for 10 h. The reaction mixture was treated
with barium carbonate; the sulfonate salt was sepa-
rated, dissolved by the heating in 100 ml of water,
mixed with 5 ml of 10% hydrochloric acid, and cooled.
The formed crystals were recrystallized from the
aqueous alcohol.
1-Methyl-2-(1'-methyl-2'-pyrrolyl)-1H-phenanthro-
[9,10-d]imidazole (Ia). To a solution of 2.97 g
(0.01 mol) of I in 10 ml of DMSO was added 0.62 g
(0.011 mol) of KOH powder, and then 1.42 g (0.01 mol)
of methyl iodide was added dropwise. The mixture
was stirred at room temperature for 2 h and diluted
with 200 ml of water. The precipitate was separated,
dried and crystallized from n-heptane.
1-Methyl-2-(1'-methyl-4(5)'-formyl-2'-pyrrolyl)-
1H-phenanthro[9,10-d]imidazoles (Ie, If). To a
cooled (0°C) solution of 1.56 g (0.005 mol) of com-
pound Ia in 7.3 g (0.1 mol) of dimethylformamide was
gradually added 1.54 g (0.01 mol) of phosphorus oxy-
chloride, maintaining the temperature of the reaction
mixture below 10–15°C. The mixture was stirred at
this temperature for 30 min and 1 h at 80°C. The
reaction mixture was poured into 50 ml of water and
neutralized with ammonia. The released oil was
extracted with chloroform and chromatographed on
alumina column. The isolated compounds Ie and If
were crystallized from n-octane.
1-Methyl-2-(1'-methyl-5’-nitro-2'-pyrrolyl)-1H-
phenanthro[9,10-d]imidazole (Ib). Preparation of the
nitrating mixture. To an Erlenmeyer flask (100 ml)
charged with 16.9 g (0.07 mol) of Cu(NO3)2·3H2O was
poured in small portions 40 ml of acetic anhydride
under strong cooling, maintaining the temperature of
the reaction mixture below 30–40°C. As the exo-
thermic reaction completed, the mixture was allowed
to stand at room temperature for 24 h. Then the
precipitate of copper(II) acetate was filtered off. The
resulting mixture was stored no longer than 10 days at
5–10°C.
1-Methyl-2-(1'-methyl-4(5)'-acetyl-2'-pyrrolyl)-
1H-phenanthro[9,10-d]imidazoles (Ig, Ih). A solu-
tion of 1.56 g (0.005 mol) of compound Ia, 7 g of
acetic anhydride and 0.05 g of perchloric acid was
heated on a boiling water bath for 6 h. The reaction
mixture was cooled, diluted with 50 ml of water, and
neutralized with aqueous ammonia. The products were
extracted with 25 ml of chloroform. The extract was
dried, concentrated, and fractionally chromatographed
on a column (h 20 cm, d 2.5 cm) with aluminum oxide,
eluting with chloroform. The isolated compounds Ig
and Ih were crystallized from n-octane.
To a solution of 1.56 g (0.005 mol) of compound Ia
in 5 ml of the freshly distilled acetic anhydride under
vigorous stirring was added in small portions 1.4 ml of
nitrating mixture at room temperature. The reaction
time was 30–40 min. Then the mixture was diluted
with 25 ml of cold water and neutralized with 23%
solution of ammonia until the slightly alkaline
reaction. The precipitate was filtered off, thoroughly
washed with water, and chromatographed on a column
with Al2O3, eluting with dichloromethane. The reac-
tion product was crystallized from alcohol. The yield,
melting point, elemental analysis data, and spectral
characteristics are shown in Table 1, 2.
1-Methyl-2-(1'-methyl-4(5)'-benzoyl-2'-pyrrolyl)-
1H-phenanthro[9,10-d]imidazoles (Ii, Ik). A mixture
of 1.56 g (0.005 mol) of compound Ia and 1.22 g
(0.01 mol) of benzoic acid in 20 g of polyphosphoric
acid was heated at 140–150°C for 1 h under vigorous
stirring. The reaction mixture was cooled, diluted with
100 ml of water, and carefully neutralized with ammo-
nia. Next, the compounds Ii and Ik were isolated
similar to the compounds Ig and Ih and crystallized
from n-octane.
1-Methyl-2-(1'-methyl-4',5'-dibromo-2'-pyrrolyl)-
1H-phenanthro[9,10-d]imidazole (Ic). To a solution
of 1.76 g (0.011 mol) of bromine in 30 ml of dichloro-
ethane cooled to –10°C was added with stirring a
cooled solution of 1.56 g (0.005 mol) of Ia in 10 ml of
dichloroethane within 30 min. The stirring was
continued at the same temperature for 1.5 h, and then
Ic hydrobromide was filtered off, washed with
dichloroethane (15 ml), dried, and neutralized with
2',2''-Di-(1-methyl-2-phenanthro[9,10-d]imida-
zolyl)-1',1''-dimethyl-4',4''-dipyrrolylmethane (Il).
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1-METHYL-2-(1'-METHYL-2'-PYRROLYL)-1H-PHENANTHRO[9,10-d]-IMIDAZOLE
1725
4. Steck, I.L. and Day, N.S., J. Am. Chem. Soc., 1943,
A mixture of 1.56 g (0.005 mol) of compound Ia, 1.4 g
(0.01 mol) of hexamine and 20 g of polyphosphoric
acid was stirred at 70–80°C for 2 h. The reaction
product was isolated similar to compounds Ig and Ih
and crystallized from xylene.
vol. 65, no. 6, p. 452.
5. Kinugawa, Y., Synthesis, 1981, vol. 12, no. 2, p. 124.
6. Yel’chaninov, M.M., Oleinikova, L.Ya., Simonov, A.M.,
Khim. Geterotsikl. Soedin., 1979, no. 8, p. 1047.
7. Yel’chaninov, M.M., Simonov A.M., Oleinikova, L.Ya.,
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