Synthesis of 1-Butyl-3,6-diazahomoadamantane

Article abstract of DOI:10.1134/S1070428019030163

1-Butyl-3,6-diazahomoadamantan-9-one was synthesized by condensation of heptan-2-one with diethylenetetramethylenetetramine (1,3,6,8-tetraazatricyclo[4.4.1.1^3,8]dodecane). Reactions of the title compound at the carbonyl group afforded 1-butyl-3

Full text of DOI:10.1134/S1070428019030163

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2019, Vol. 55, No. 3, pp. 368–372. © Pleiades Publishing, Ltd., 2019.
Russian Text © The Author(s), 2019, published in Zhurnal Organicheskoi Khimii, 2019, Vol. 55, No. 3, pp. 427–432.
Synthesis of 1-Butyl-3,6-diazahomoadamantane
R. T. Alasadia, A. H. A. Al-Yasaria, H. F. Abdulhasana, V. V. Kalashnikovb, and T. M. Serovab*
a University of Kerbala, P.O. Box 1125, Kerbala, Iraq
b Institute of Physiologically Active Compounds, Russian Academy of Sciences,
Severnyi proezd 1, Chernogolovka, Moscow oblast, 142432 Russia
*e-mail: tetraza@mail.ru
Received June 14, 2018; revised June 25, 2018; accepted September 11, 2018
Abstract—1-Butyl-3,6-diazahomoadamantan-9-one was synthesized by condensation of heptan-2-one with
diethylenetetramethylenetetramine (1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane). Reactions of the title com-
pound at the carbonyl group afforded 1-butyl-3,6-diazahomoadamantane and derivatives containing functional
groups on the C9 bridging atom. Introduction of pharmacophoric groups into the 9-position of 1-butyl-3,6-
diazahomoadamantane seems to be the most promising method for its modification with a view to obtaining
derivatives with new biological properties.
Keywords: condensation, heptan-2-one, [14.22]adamanzane, 1-butyl-3,6-diazahomoadamantan-9-one, 1-butyl-
3,6-diazahomoadamantane and its derivatives.
DOI: 10.1134/S1070428019030163
We previously described the synthesis of a number
of 1-substituted 3,6-diazahomoadamantan-9-ones by
condensation of ketones with diethylenetetramethy-
lenetetramine ([14.22]adamanzane, 1,3,6,8-tetraazatri-
cyclo[4.4.1.13,8]dodecane) and their further trans-
formations to 3,6-diazahomoadamantane and its deriv-
atives [1, 2]. It is known that heptan-2-one is an alarm
pheromone of bees; it shows analgesic and pronounced
anesthetic properties and therefore can be used to
obtain local anesthetics [3–7]. In continuation of our
studies on the synthesis of new 3,6-diazahomoadaman-
tane derivatives, by condensation of heptan-2-one with
diethylenetetramethylenetetramine we obtained
1-butyl-3,6-diazahomoadamantan-9-one (1) which
retained the initial heptane-2-one smell. It was antici-
pated that compound 1 would possess both pheromone
and analgesic and anesthetic properties.
at room temperature (Scheme 1). Compound 1 was
also synthesized starting from ethylenediamine and
paraformaldehyde in a one-pot fashion without isola-
tion of diethylenetetramethylenetetramine. The IR
spectrum of 1 displayed a carbonyl stretching band at
1
1711 cm–1. Its H NMR spectrum contained a set of
signals typical of diazahomoadamantane skeleton,
namely two AB systems due to NCH2C protons,
a multiplet of the NCH2CH2N ethylene bridge, and
a singlet at δ 2.53 ppm due to proton in the bridge-
head position. The butyl group gave rise to a triplet at
δ 0.88 ppm (CH3) and multiplets in the region δ 1.14–
1.37 ppm (6H, CH2). In the mass spectrum of 1 we
observed the molecular ion peak with m/z 222 [M]+
whose main decomposition pathway involved cleavage
of the cage skeleton with the formation of ions with
m/z 72 and 58.
The reaction of diethylenetetramethylenetetramine
with heptan-2-one was carried out in isopropyl alcohol
Diazahomoadamantanone 1 is a promising interme-
diate product for the preparation of new diazahomo-
Scheme 1.
N
O
O
AcOH
+
N
N
N
N
N
Me
Me
Bu
1
368

SYNTHESIS OF 1-BUTYL-3,6-DIAZAHOMOADAMANTANE
369
Scheme 2.
Bu
Bu
Bu
N
O
N
OH
NH2
NH2OH
N2H4·H2O
N
N
N
N
N
N
2
1
5
Raney Ni
NaOH
i-PrOH
NaOH
KOH
220–245°C
Bu
Bu
Bu
NH2
OH
N
N
N
N
N
N
3
4
6
adamantane derivatives via functionalization at the
carbonyl group (Scheme 2). Treatment of 1 with
hydroxylamine gave oxime 2 which was reduced to
amine 3 over Raney nickel an aqueous alkali. The IR
spectrum of 2 showed absorption bands at 1620 and
3240 cm–1 due to stretching vibrations of C=N bond
and OH group, respectively. The fragmentation of 2
under electron impact was characterized by elimination
of OH radical from the molecular ion to give [M – 17]+
ion.
protons was a multiplet at δ 3.05 ppm. The butyl
substituent was represented by a triplet at δ 0.89 ppm
(Me) and multiplets in the region δ 1.01–1.40 ppm
(6H, CH2).
In the IR spectrum of 7 we observed C=N stretch-
ing band at 1635 cm–1, whereas no bands assignable to
NH2 group were present. Each of the C=N bonds in
molecule 7 may have cis or trans configuration, so that
the formation of isomer mixture is possible. In our
case, both C=N bonds are configured trans, which is
1
confirmed by the H NMR spectrum where only one
Ketone 1 was reduced to odorless alcohol 4 which
displayed OH stretching band in the IR spectrum at
3290–3430 cm–1. The reaction of 1 with hydrazine
hydrate followed different paths, depending on the
temperature. The corresponding hydrazone 5 was
formed at a temperature below 50°C, whereas azine 7
was obtained when a mixture of ketone 1 and 80% hy-
drazine hydrate was heated under reflux (Scheme 3).
Treatment of hydrazone 5 with excess potassium hy-
droxide at 220–245°C afforded 1-butyl-3,6-diaza-
8-H signal was observed at δ 2.53 ppm [8]. The mass
spectrum of 7 contained the molecular ion peak with
m/z 440 [M]+ and [M/2]+ peak with m/z 220. The main
fragmentation path of the molecular ion is decom-
position of the cage skeleton with the formation of
CH2=N+CH2, CH2=N+(CH3)2, and CH3CH=N+(CH3)2
ions with m/z 42, 58, and 72, respectively.
It is known that thiosemicarbazones are promising
compounds from the viewpoint of searching for new
chemotherapeutic agents [9–11]. Introduction of
a pharmacophoric group into the 9-position of butyl-
diazahomoadamantane seemed to be the most appro-
priate method of its modification with the goal of
obtaining compounds possessing new biological
properties. For this purpose, hydrazone 5 was reacted
1
homoadamantane (6). In the H NMR spectrum of 6,
methylene protons of the C9H2 group resonated as
a singlet at δ 1.60 ppm, the singlet at δ 1.82 ppm was
assigned to CH proton in the bridgehead position (C8),
four NCH2C groups gave doublets at δ 2.11, 2.25,
2.63, and 3.25 ppm, and the signal of the NCH2CH2N
Scheme 3.
Bu
Bu
N
N
O
N2H4·H2O
N
2
N
N
N
N
N
Bu
1
7
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019

ALASADI et al.
370
Scheme 4.
Bu
Bu
S
N
N
R
NH2
N
N
RNCS
H
H
N
N
N
N
5
8–10
8, R = Me; 9, R = Ph; 10, R = MeO(CH2)2.
with methyl, phenyl, and 2-methoxyethyl isothiocy-
anates. As a result, we isolated N-substituted thiosemi-
carbazones 8–10 (Scheme 4) whose structure was
confirmed by spectral data.
b. Paraformaldehyde, 6.00 g (200 mmol), was
added to a solution of 6.00 g (100 mmol) of ethylene-
diamine in 50 mL of isopropyl alcohol, and the mix-
ture was stirred until it became homogeneous. Heptan-
2-one, 6.30 g (55 mmol), and acetic acid, 9.00 g
(150 mmol), were added to the resulting solution, and
the mixture was stirred for 72 h at room temperature.
The product was isolated and purified as described
above in a. Yield 3.90 g (35%) (a), 3.65 g (33%) (b);
white crystals, mp 65–67°C (from n-heptane). IR spec-
Fragmentation of molecular ions of 3,6-diazahomo-
adamantane derivatives is characterized by formation
of ions both common for these compounds and those
resulting from decomposition of the functional substit-
uent. The molecular ion of 5 decomposed via cleavage
of the N–N bond to peoduce [M – NH2]+ and
[M – NAd]+ ions, followed by elimination of nitrogen-
containing molecules CnH2n+1N (n = 1–3). The mass
spectra of thiosemicarbazones 8–10 characteristically
displayed elimination of the NHC(S)NHR substituent
from the molecular ion.
1
trum: ν 1711 cm–1 (C=O). H NMR spectrum, δ, ppm:
0.88 t (3H, CH3, J = 7.4 Hz), 1.14–1.32 m (4H, CH2),
1.37 m (2H, CH2), 2.53 s (1H, CH), 3.04 m (4H,
NCH2CH2N), 3.09–3.24 m (6H, NCH2C), 3.39 d (2H,
NCH2C, J = 13.9 Hz). 13C NMR spectrum, δC, ppm:
212.10 (C9), 61.30 (C2, C10), 59.15 (C4, C5), 57.30 (C7,
C11), 51.10 (C8), 44.95 (C1), 33.10 (1-CH2), 27.25
(1-CH2CH2), 23.15 (CH2Me), 15.05 (Me). Mass spec-
trum, m/z (Irel, %): 222 (100) [M]+, 164 (73), 150 (30),
137 (19), 131 (21), 122 (20), 101 (50), 72 (35), 58 (60)
57 (40), 43 (41). Found, %: C 70.12; H 10.11; N 12.49.
C13H22N2O. Calculated, %: C 70.23; H 9.97; N 12.60.
M 222.33.
Thus, we have synthesized previously unknown
3,6-diazahomoadamantane derivatives which attract
interest as potential biologically active compounds.
EXPERIMENTAL
The IR spectra were recorded in KBr on a Bruker
1
IFS spectrometer. The H and 13C NMR spectra were
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
one oxime (2). Hydroxylamine hydrochloride, 0.42 g
(6 mmol), was added to a solution of 1.10 g (5 mmol)
of compound 1 in 5 mL of water. The mixture was
heated to 60–70°C, and a solution of 0.62 g (6 mmol)
of sodium carbonate in 5 mL of water was added in
portions over a period of 15 min with continuous
stirring. The mixture was stirred for 10 min more at
that temperature, and the precipitate was filtered off,
dried, and recrystallized from toluene. Yield 0.85 g
(73%), white crystals, mp 157–158°C. IR spectrum, ν,
recorded from solutions in CDCl3 on a Bruker AM-300
spectrometer at 300.13 and 75.47 MHz, respectively,
using TMS as internal standard. The mass spectra
(electron impact, 70 eV) were obtained on a Kratos
MS-30 instrument with direct sample admission into
the ion source (ion source temperature 200°C).
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
one (1). a. A mixture of 8.40 g (50 mmol) of diethy-
lenetetramethylenetetramine, 6.30 g (55 mmol) of
heptan-2-one, and 9.00 g (150 mmol) of acetic acid in
50 mL of isopropyl alcohol was stirred for 72 h at
room temperature. The mixture was then concentrated
under reduced pressure, the viscous residue was
extracted with hot n-heptane (4×40 mL), and the warm
extract was passed through a layer of anhydrous
alumina (10 g, Brockmann activity II) on a Schott
filter. The solvent was distilled off, and the residue was
recrystallized from n-heptane.
1
cm–1: 3240 (OH), 1620 (C=N). H NMR spectrum, δ,
ppm: 0.88 t (3H, CH3, J = 7.4 Hz), 1.15–1.33 m (4H,
CH2), 1.37 m (2H, CH2), 2.53 s (1H, CH), 3.04 m (4H,
NCH2CH2N), 3.09–3.24 m (6H, NCH2C), 3.39 d (2H,
NCH2C, J = 14.0 Hz), 8.60 s (1H, OH). Mass spec-
trum, m/z (Irel, %): 237 (100) [M]+, 220 (100), 194
(09), 177 (40), 163 (05), 121 (10), 72 (20), 58 (37), 43
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019

SYNTHESIS OF 1-BUTYL-3,6-DIAZAHOMOADAMANTANE
371
(10), 42 (50). Found, %: C 65.85; H 9.73; N 17.63.
C13H23N3O. Calculated, %: C 65.79; H 9.77; N 17.70.
M 237.34.
crystals, mp 125–126°C. IR spectrum, ν, cm–1: 1630
(C=N), 3270, 3360 (NH). H NMR spectrum, δ, ppm:
1
0.85 t (3H, CH3, J = 7.4 Hz), 1.18–1.35 m (4H, CH2),
1.40 m (2H, CH2), 2.50 s (1H, CH), 3.02 m (4H,
NCH2CH2N), 3.10–3.26 m (6H, NCH2C), 3.38 d (2H,
NCH2C, J = 13.9 Hz), 5.17 br.s (2H, NH2). Mass spec-
trum, m/z (Irel, %): 236 (100) [M]+, 200 (25), 207 (10),
194 (14), 178 (13), 164 (09), 121 (16), 72 (95), 58
(36), 42 (45). Found, %: C 66.20; H 10.35; N 23.50.
C13H24N4. Calculated, %: C 66.06; H 10.23; N 23.70.
M 236.36.
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecane (6).
Hydrazone 5, 0.60 g (2.5 mmol), was thoroughly
mixed with 0.6 g (11 mmol) of potassium hydroxide,
and the mixture was heated for 2 h at 220–240°C.
The mixture was cooled and extracted with toluene
(3×20 mL), the solvent was distilled off from the
extract, and the residue was recrystallized from tol-
uene. Yield 0.25 g (47%), white crystals, mp 39–40°C
(from toluene). 1H NMR spectrum, δ, ppm: 0.89 t (3H,
CH3, J = 6.90 Hz), 1.01–1.22 m (4H, CH2), 1.40 m
(2H, CH2), 1.60 s (2H, CH2), 1.82 s (1H, CH); 2.11 d,
2.25 d, and 2.63 d (2H each, NCH2C, J = 14.0 Hz);
3.05 m (4H, NCH2CH2N), 325 d (2H, NCH2C, J =
14.0 Hz). Mass spectrum, m/z (Irel, %): 208 (60) [M]+,
193 (11), 150 (32), 124 (42), 112 (22), 108 (42), 83
(20), 72 (100), 58 (23), 57 (44), 43 (71), 42 (50).
Found, %: C 74.75; H 11.47; N 13.32. C13H24N2.
Calculated, %: C 74.94; H 11.61; N 13.45. M 208.34.
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
amine (3). A solution of 1.84 g of sodium hydroxide in
15 mL of water was added dropwise with vigorous
stirring over a period of 1 h to a suspension of 0.50 g
(2.10 mmol) of oxime 2 and 1.84 g of Raney nickel
(Ni–Al, 50:50) in 10 mL of water at such a rate that
the temperature of the mixture did not exceed 50°C.
The mixture was then stirred for 2 h more, cooled, and
filtered, and the filtrate was extracted with diethyl
ether (3×10 mL). The extract was dried over potas-
sium hydroxide and evaporated. Yield 0.36 g (77 %),
white crystals, mp 86–88°C. IR spectrum, ν, cm–1:
1
3395, 3246 (NH2). H NMR spectrum, δ, ppm: 0.87 t
(3H, CH3, J = 6.9 Hz), 1.16–1.38 m (4H, CH2), 1.42 m
(2H, CH2), 1.62 s (2H, NH2), 1.79 br.s (1H, CH);
2.30 d, 2.45 d, and 2.58 d (2H each, NCH2C, J =
14.0 Hz); 3.04 m (4H, NCH2CH2N), 3.32 d (1H,
CHNH2, J = 11.0 Hz), 3.49 d (2H, NCH2C, J =
14.0 Hz). Mass spectrum, m/z (Irel, %): 223 (100) [M]+,
181 (14), 165 (23), 150 (35), 138 (36), 98 (25), 83
(30), 72 (60), 58 (50), 57 (27), 42 (71). Found, %:
C 69.75; H 11.37; N 18.65. C13H25N3. Calculated, %:
C 69.91; H 11.28; N 18.81. M 223.36.
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-ol
(4). A mixture of 0.50 g (2.25 mmol) of ketone 1 and
0.06 g (2.50 mmol) of anhydrous sodium hydroxide in
10 mL of isopropyl alcohol was refluxed for 3.5 h. The
solvent was distilled off, and the dry residue was
extracted with toluene (2×10 mL), the extract was
evaporated, and the residue was recrystallized from
toluene. Yield 0.39 g (78%), white crystals, mp 124–
125°C. IR spectrum, ν, cm–1: 3430, 3297 (OH).
1H NMR spectrum, δ, ppm: 0.88 t (3H, CH3, J =
7.4 Hz), 1.14–1.32 m (4H, CH2), 1.37 m (2H, CH2),
2.53 s (1H, CH), 3.04 m (4H, NCH2CH2N), 3.10–
3.28 m (6H, NCH2C), 3.38 d (2H, NCH2C, J =
13.9 Hz), 3.45 s (1H, CHOH), 3.58 s (1H, OH). Mass
spectrum, m/z (Irel, %): 224 (95) [M]+, 207 (12), 181
(30), 167 (33), 166 (35), 152 (27), 111 (40), 72 (65),
58 (100), 42 (85). Found, %: C 69.45; H 10.89;
N 12.31. C13H24N2O. Calculated, %: C 69.60; H 10.78;
N 12.49. M 224.34.
1,2-Bis(1-butyl-3,6-diazatricyclo[4.3.1.13,8]un-
decan-9-ylidene)hydrazine (7). A solution of 1.10 g
(5 mmol) of ketone 1 in 5 mL of 80% hydrazine
hydrate was refluxed for 3 h. The mixture was
evaporated, and the residue was recrystallized from
toluene. Yield 0.95 g (87%), white crystals, mp 177–
1
179°C. IR spectrum: ν 1635 cm–1 (C=N). H NMR
spectrum, δ, ppm: 0.85 t (6H, CH3, J = 7.4 Hz), 1.18–
1.35 m (8H, CH2), 1.40 m (4H, CH2), 2.53 s (2H, CH),
3.01 m (8H, NCH2CH2N), 3.10–3.26 m (12H,
NCH2C), 3.38 d (4H, NCH2C, J = 13.9 Hz). Mass
spectrum, m/z (Irel, %): 440 (25) [M]+, 397 (4), 356 (6),
282 (7), 220 (47), 177 (10), 150 (05), 72 (100), 58
(20), 42 (19). Found, %: C 70.97; H 10.17; N 18.95.
C26H44N6. Calculated, %: C 70.86; H 10.06; N 19.07.
M 439.99.
1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
one thiosemicarbazones 8–10 (general procedure).
A mixture of 4 mmol of hydrazone 5 and 4 mmol of
the corresponding isothiocyanate in 15 mL of toluene
was refluxed for 2 h. The mixture was cooled, and the
(1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
ylidene)hydrazine (5). A solution of 1.10 g (5 mmol)
of ketone 1 in 10 mL of 80% hydrazine hydrate was
heated for 3 h at a temperature not exceeding 50°C.
The mixture was evaporated, and the residue was
recrystallized from toluene. Yield 1.0 g (85%), white
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019

ALASADI et al.
372
precipitate was filtered off and recrystallized from
isopropyl alcohol.
REFERENCES
2-(1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
ylidene)-N-methylhydrazine-1-carbothioamide (8).
Yield 1.10 g (84%), white crystals, mp 136–137°C.
IR spectrum, ν, cm–1: 3385, 3310 (NH), 1632 (C=N),
1577 (NCSN). Mass spectrum, m/z (Irel, %): 309 (38)
[M]+, 278 (15), 220 (21), 191 (30), 167 (25), 157 (27),
119 (46), 72 (60), 58 (90), 43 (75). Found, %: C 58.14;
H 8.68; N 22.81. C15H27N5S. Calculated, %: C 58.21;
H 8.79; N 22.63. M 309.47.
1. Razenko, I.O., Serova, T.M., and Kuznetsov, A.I., Russ.
Chem. Bull., Int. Ed., 2016, vol. 65, p. 2458. doi
10.1007/s11172-016-1606-6
2. Kuznetsov, A.I., Alasadi, R.T., Senan, I.M., and
Serova, T.M., Russ. Chem. Bull., Int. Ed., 2015, vol. 64,
p. 962. doi 10.1007/s11172-015-0964-9
3. Vallet, A., Cassier, P., and Lensky, Y., J. Insect Physiol.,
1991, vol. 37, p. 789. doi 10.1016/0022-1910(91)
90076-C
4. Albro, P.W., Corbett, J.T., and Schroeder, J.L., Chem.-
Biol. Interact., 1984, vol. 51, p. 295. doi 10.1016/0009-
2797(84)90155-8
2-(1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
ylidene)-N-phenylhydrazine-1-carbothioamide (9).
Yield 1.20 g (76%), white crystals, mp 161–162°C
(from i-PrOH). IR spectrum, ν, cm–1: 3400, 3330
(NH), 1625 (C=N), 1599 (C=Carom), 1558 (NCSN).
Mass spectrum, m/z (Irel, %): 371 (11) [M]+, 279 (47),
220 (80), 175 (23), 160 (21), 152 (27), 105 (33), 72
(50), 58 (80), 42 (70). Found, %: C 64.19; H 7.78;
N 19.09. C20H29N5S. Calculated, %: C 64.65; H 7.87;
N 18.85. M 371.54.
2-(1-Butyl-3,6-diazatricyclo[4.3.1.13,8]undecan-9-
ylidene)-N-(2-methoxyethyl)hydrazine-1-carbothio-
amide (10). Yield 1.00 g (67%), white crystals,
mp 125–126°C (from i-PrOH). IR spectrum, ν, cm–1:
3385, 3310 (NH), 1632 (C=N), 1577 (NCSN), 1259,
1128 (OCH3). Mass spectrum, m/z (Irel, %): 353 (38)
[M]+, 279 (30), 220 (21), 191 (30), 167 (25), 157 (27),
119 (46), 72 (60), 58 (90), 43 (75). Found, %: C 57.23;
H 8.69; N 19.74. C17H31N5S. Calculated, %: C 57.76;
H 8.84; N 19.81. M 353.53.
5. Barber, E.D., Miller, K.R., Banton, M.I., and
Reddy, M.V., Mutat. Res., 1999, vol. 442, p. 133. doi
10.1016/S1383-5718(99)00072-8
6. Prokopy, R.J., Hu, Xi., Jang, E.B., Vargas, R.I., and
Warthen, J.D., J. Chem. Ecol., 1998, vol. 24, p. 1293.
doi 10.1023/A:1021218531083
7. Gutiérrez-García, A.G., Contreras, C.M., Mendoza-
López, M.R., García-Barradas, O., and Cruz-Sán-
chez, J.S., Physiol. Behav., 2007, vol. 91, p. 166. doi
10.1016/j.physbeh.2007.02.006
8. Morgenstern, K., Prog. Surf. Sci., 2011, vol. 86, p. 115.
doi 10.1016/j.progsurf.2011.05.0020
9. Zhu, T.-H., Cao, S.-W., and Yu, Y.-Y., Int. J. Biol.
Macromol., 2013, vol. 62, p. 589. doi 10.1016/
j.ijbiomac.2013.09.056
10. Pelosi, G., Bisceglie, F., Bignami, F., Ronzi, P.,
Schiavone, P., Re, M.C., Casoli, G., and Pilotti, E.,
J. Med. Chem., 2010, vol. 53, p. 8765. doi 10.1021/
jm1007616
11. Jallapally, A., Addla, D., Yogeeswari, P., Sriram, D., and
Kantevari, S., Bioorg. Med. Chem. Lett., 2014, vol. 24,
p. 5520. doi 10.1016/j.bmcl.2014.09.084
CONFLICT OF INTERESTS
No conflict of interests is declared by the authors.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 3 2019