Synthesis and antiherpetic activity of novel purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine

Article abstract of DOI:10.1007/s10593-021-02929-z

[Figure not available: see fulltext.] A method for the synthesis of novel purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine containing fragments of ω-amino acids with different lengths of the polymethylene chain as a linker has been developed. It was found in experiments in vitro that the obtained compounds are active against the herpes simplex virus type 1, including the acyclovir-resistant strain.

Full text of DOI:10.1007/s10593-021-02929-z

DOI 10.1007/s10593-021-02929-z
Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
Synthesis and antiherpetic activity of
novel purine conjugates with
7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine
Olga А. Vozdvizhenskaya1, Valeriya L. Andronova2, Georgii А. Galegov2,
Galina L. Levit1, Victor P. Krasnov1,3*, Valery N. Charushin1,3
1 Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences,
22/20 Sofyi Kovalevskoi St., Yekaterinburg 620108, Russia; e-mail: ca@ios.uran.ru
2 D. I. Ivanovsky Institute of Virology,
Gamaleya National Research Center of Epidemiology and Microbiology, Ministry of Health of the Russian Federation,
16 Gamaleya St., Moscow 123098, Russia; e-mail: andronova.vl@yandex.ru
3 Institute of Chemical Engineering, Ural Federal University,
19 Mira St., Yekaterinburg 620062, Russia
Translated from Khimiya Geterotsiklicheskikh Soedinenii,
2021, 57(4), 490–497
Submitted November 9, 2020
Accepted February 4, 2021
A method for the synthesis of novel purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine containing fragments
of ω-amino acids with different lengths of the polymethylene chain as a linker has been developed. It was found in experiments in vitro
that the obtained compounds are active against the herpes simplex virus type 1, including the acyclovir-resistant strain.
Keywords: ω-amino acids, 6-chloropurine, 7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine, antiviral activity, herpes simplex
virus type 1.
Herpes simplex virus type 1 (HSV-1) is a widespread
viral infection. According to WHO estimates, in 2016
about 3.7 billion people under the age of 50 (67% of the
world population) were infected with HSV-1.1 After being
introduced into the body, HSV-1 remains in the latent form
throughout a person's life with periodic episodes of
reactivation.2 HSV is one of the significant causes of death
among immunocompromised patients.3
The most effective drugs for the treatment of herpesvirus
infection are the derivatives of purine (imidazo[4,5-d]-
pyrimidine) such as acyclovir, famciclovir, penciclovir,
valacyclovir, etc. (Fig. 1).1,4 The mechanism of the antiviral
action of these drugs is based on their ability to undergo
phosphorylation (with the participation of viral thymidine
kinase) with the formation of the corresponding tri-
Figure 1. Acyclovir and other antiherpetic drugs.
phosphates – selective inhibitors of viral DNA polymerase –
0009-3122/21/57(4)-0490©2021 Springer Science+Business Media, LLC
490

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
which compete with 2'-deoxyguanosine triphosphate
causing the termination of replication after inclusion in the
synthesized DNA strand.
One of the main problems in the treatment of
herpesvirus infections is the emergence of HSV strains
resistant to the action of acyclovir and its analogs.5 In this
regard, the search for new antiherpetic agents with different
mechanisms of action that are active against resistant
strains is an urgent task.
In recent years, our efforts have been focused on the
synthesis of new purine derivatives and the search for
compounds with high biological activity among them.6 In
particular, we have synthesized a number of purine and
Figure 2. Purine conjugates with 7,8-difluoro-3-methyl-3,4-dihydro-
2H-1,4-benzoxazine with high antiherpetic activity.
2-aminopurine conjugates containing in position
6
reaction of ester 4 with (COCl)2 in CH2Cl2, was converted
into the acyl azide which was then subjected to the Curtius
rearrangement followed by acidic hydrolysis of the
resulting isocyanate to 9-aminononanoic acid hydro-
chloride (2b).7a Amino acid 2e was also synthesized by
analogy with the described methods8 from cyclo-
pentadecanone (5) by forming the cyclooxime in situ by the
action of hydroxylamine-O-sulfonic acid followed by the
intramolecular Beckmann rearrangement with the
formation of lactam 6 and its acidic hydrolysis with HCl
(Scheme 1).
fragments of various heterocyclic amines bound to the
purine ring directly6b or via an amino acid linker.6c,d,i The
results of biological testing showed that conjugates of
purine with racemic 7,8-difluoro-3-methyl-3,4-dihydro-2H-
1,4-benzoxazine containing a fragment of ω-amino acid
NH(CH2)nCO (n = 5 or 7, compounds 1a,b, Fig. 2) as a
linker exhibit high antiviral activity in vitro against HSV-1,
including the acyclovir-resistant strain.6i It was also found
that derivatives containing a fragment of a "shorter"
ω-amino acid (glycine, β-alanine, γ-aminobutyric acid, or
5-aminopentanoic acid (n = 1–4)) have no inhibitory
activity against HSV-1.6i
The aim of this study was to synthesize and investigate
the antiherpetic activity of novel purine derivatives,
analogs of compounds 1a,b containing the fragment of
another "longer" ω-amino acid as a linker.
ω-Amino acids with different aliphatic chain lengths,
7-aminoheptanoic (compound 2a, n = 6), 9-aminononanoic
(compound 2b, n = 8), 11-aminoundecanoic (compound 2c,
n = 10), 12-aminododecanoic (compound 2d, n = 11), and
15-aminopentadecanoic (compound 2e, n = 14) acids, were
used as the starting compounds (Scheme 1). Amino acids
2a,c,d are commercially available, amino acids 2b,e were
obtained by modified known methods.
The amino group of ω-amino acids was protected by
phthaloylation by fusing compounds 2a,c–e with phthalic
anhydride (PhthO) by analogy with the known procedure
(Scheme 2).9 N-Phthaloyl derivative 7b was obtained by
heating amino acid hydrochloride 2b and PhthO in PhMe
in the presence of Et3N under reflux. Acyl chlorides 8a–e
were obtained from N-phthaloylamino acids 7a–e by the
10
action of (COCl)2 and subsequently used in the acylation
reaction without additional purification. Acylation of
7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine (9)
with the corresponding acyl chlorides 8a–e was carried out
in CH2Cl2 at room temperature in the presence of
N,N-diethylaniline (Scheme 2). Phthaloyl derivatives 10a–e
containing fragments of 7-aminoheptanoic, 9-amino-
nonanoic, 11-aminoundecanoic, 12-aminododecanoic, and
15-aminopentadecanoic acids were obtained in 60–71%
yields.
Amino acid 2b was obtained from sebacic acid (3) by
analogy with known methods7 by esterification and
subsequent selective demethylation in the presence of
Ba(OH)2, which led to the formation of monomethyl ester
4 (Scheme 1). The acid chloride formed as a result of the
The N-phthaloyl protecting group of compounds 10a–e
was removed by hydrazinolysis in EtOH under reflux, after
Scheme 1
491

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
From 2a,c–e
Scheme 2
(COCl)2
PhthO,180°C, 2 h
HOOC
NH2
HOOC
NPhth
ClOC
Cl
NPhth
n
8a–e
From 2b
PhthO, Et3N, PhMe, 2 h
41–89%
CH2Cl2, rt, 6 h
87–92%
n
n
2a–e
7a–e
a n = 6, b n = 8, c n = 10, d n = 11, e n = 14
N
Me
N
O
F
F
O
N
F
F
N
H
F
N
8a–e
PhNEt2
O
N
F
O
N
F
O
F
H2N–NH2·H2O
Et3N
n
HN
CH2Cl2
rt, 2 days
60–71%
EtOH, , 2 h
n-BuOH
90°C, 10 h
44–66%
Me
Me
N
Me
N
H
N
NPhth
n
NH2
9
O
O
n
N
H
12a–e
N
10a–e
11a–e
which amines 11a–e were introduced without isolation into
the nucleophilic substitution reaction of the chlorine atom
in 6-chloropurine to afford conjugates of purine and
7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine (com-
pounds 12a–e) connected by linkers of various lengths in
good yields (44–66%) (Scheme 2).
percentage of viable cells was determined by the trypan
blue staining.
Among the synthesized compounds, conjugate 12b contain-
ing the 9-aminononanoic acid fragment (ID50 4.26 μM),
which is structurally similar to the active homolog 1b, a
derivative of 8-aminooctanoic acid, has the highest activity.
The high selectivity of its antiviral action as indicated by
the high selectivity index (SI 19) is notable. Compound 12c
(ID50 4.64 μM) which contains the 11-aminoundecanoic acid
fragment as a linker is comparable in activity to conjugate
12b. However, compound 12c has high cytotoxicity
(CD50 21.54 μM) and, accordingly, lower selectivity (SI 5).
Compound 12e with the maximum linker length (n = 14)
of the studied compounds also exhibits high antiherpetic
activity (ID50 7.14 μM).
Thus, we have obtained a series of purine conjugates with
7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine with
fragments of ω-amino acids with different lengths of aliphatic
chains as a linker. The obtained compounds have high anti-
viral activity against both herpes simplex virus type 1 strain
and against the acyclovir-resistant strain. Further modifica-
The study of the antiviral activity of the synthesized
compounds 1a,b and 12a–e was carried out against the
HSV-1/L2 reference strain and the acyclovir-resistant
HSV-1/L2/R strain in Vero E6 cells (Table 1) by cyto-
pathogenic effect (CPE) inhibition assay as previously
described.6i The HSV-1/L2 strain was obtained from the
State Collection of Viruses of the D. I. Ivanovsky Institute
of Virology, the HSV-1/L2/R strain was obtained by serial
passage of the HSV-1/L2 in the presence of acyclovir
followed by cloning. Acyclovir and foscarnet (sodium
phosphonoformate hexahydrate), the drug of choice in
clinical practice in case of ineffectiveness of acyclovir and
related compounds, including cases of drug resistance
development, were used as the reference drugs. To assess
the cytotoxicity of the synthesized compounds, the
Table 1. Cytotoxicity and antiviral activity of compounds 1a,b and 12a–e
against strains of herpes simplex virus type 1 in Vero E6 cells*
Strain HSV-1/L2
ID50,*** μM
Strain HSV-1/L2/R
ID50,*** μМ
Compound
CD50,** μM
SI*4
SI*4
1a (n = 5)6i
12a (n = 6)
1b (n = 7) 6i
12b (n = 8)
12c (n = 10)
12d (n = 11)
12e (n = 14)
Acyclovir
293.37 ± 21.64
249.43 ± 4.79
89.99 ± 12.55
79.15 ± 3.75
21.54 ± 0.72
196.17 ± 7.33
51.48 ± 3.19
> 444
9.3
72.60
2.3
32
3
9.3
74.22
2.3
32
3
39
39
9
4.26
4.64
18.56
7.14
1.73
104
19
8.52
9.28
37.11
7.14
> 444
104
5
2
10
5
7
7
> 256
> 6.4
1
Foskarnet
> 667
> 6.4
* Multiplicity of infection 0.1 PFU/cell. The results were taken into account after 48 h, when the control infected cell culture was completely affected, that
is, 100% CPE had developed; the results of two independent experiments are presented.
* CD50 – concentration of the compound causing the death of 50% of cultured cells.
** ID50 – concentration of the compound that inhibits the development of the virus-induced CPE by 50%.
*** SI – selectivity index, calculated as the CD50/ID50 ratio.
492

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
tion of the structure of these compounds can lead to more
active antiherpetic agents with a new mechanism of action.
over MgSO4 and evaporated to dryness. The residue was
heated under reflux in PhH (100 ml) for 1 h, then
evaporated. Concentrated HCl (15 ml) was added to the
resulting residue, the mixture was heated under reflux for
3 h, and evaporated to dryness. The residue was recrystal-
lized from a MeOH–Et2O, 4:1. Yield 2.0 g (84%), white
powder, mp 132–133°С (MeOH–Et2O) (mp 133–134°C
Experimental
1H, 13C, and 19F NMR spectra were acquired on a Bruker
Avance 500 spectrometer (500, 125, 470 MHz,
respectively) in DMSO-d6. TMS (for Н NMR spectra),
(MeOH–Et2O)7a). H NMR spectrum, δ, ppm: 1.20–1.34
1
1
C6F6 (for 19F NMR spectra), or the signal of the solvent
DMSO-d6 (39.5 ppm for 13С NMR spectra) were used as
internal standards. Elemental analysis was performed on a
PerkinElmer Series II 2400 CHN-analyzer. Melting points
were determined on an SMP3 apparatus (Barloworld
Scientific, the United Kingdom). Monitoring of the
reaction progress and assessment of the purity of
synthesized compounds were done by TLC on Sorbfil
(Imid LLC, Russia) plates. Silica gel 60 (230–400 mesh)
(Alfa Aesar, the United Kingdom) was used for flash
chromatography.
(8H, m, (CH2)4); 1.42–1.60 (4H, m, CH2(CH2)4CH2); 2.14–
2.24 (2H, m, CH2CO); 2.68–2.80 (2H, m, CH2N); 7.75–
8.05 (3H, m, NH3Cl); 11.99 (1H, s, COOH). Found, %:
C 51.61; H 9.69; Cl 16.63; N 6.78. C9H20ClNO2.
Calculated, %: C 51.55; H 9.61; Cl 16.91; N 6.68.
15-Aminopentadecanoic acid lactam (6). A suspension
of hydroxylamine-O-sulfonic acid (3.7 g, 33.0 mmol) in
HCOOH (25 ml) was added to a solution of cyclopenta-
decanone (5) (5.0 g, 22.0 mmol) in HCOOH (25 ml). The
reaction mixture was heated under reflux for 16 h, then
poured into H2O (200 ml), and the resulting mixture was
extracted with AcOEt (3×30 ml). The combined organic
phases were washed successively with 5% aqueous
NaHCO3 (5×20 ml) and saturated aqueous NaCl (3×20 ml),
dried over MgSO4, and evaporated to dryness. The residue
was purified by column chromatography on SiO2 (eluent
AcOEt). Yield 4.1 g (78%), white powder, mp 134–135°С
The solvents were purified using standard procedures.
7,8-difluoro-3-methyl-3,4-dihydro-2H-1,4-benzoxazine (9)
was obtained by the known method.11 The rest of the reagents
are commercially available and were purchased from Alfa
Aesar; solvents were purchased from Vekton (Russia).
Monomethyl sebacate (4). Concentrated H2SO4 (2.4 ml,
44.2 mmol) was added to a solution of acid 3 (5.0 g,
24.7 mmol) in MeOH (25 ml). The reaction mixture was
heated under reflux for 2 h, then cooled to room
temperature and poured into H2O (100 ml). The resulting
mixture was extracted with PhH (5×25 ml). The combined
organic fractions were washed with saturated aqueous
NaCl (3×25 ml), 5% aqueous NaHCO3 (3×25 ml), and H2O
(3×25 ml). The organic layer was separated, dried over
MgSO4, and evaporated to dryness under reduced pressure.
The residue was dissolved in MeOH (20 ml), then a
suspension of Ba(OH)2 (4.8 g, 15.2 mmol) in MeOH (30 ml)
was added. The reaction mixture was kept at room
temperature for 2 h. The precipitate was filtered off,
washed with MeOH, and suspended in H2O (200 ml). pH
was adjusted to 3 by the addition of 4 M HCl, and the
resulting mixture was extracted with CH2Cl2 (5×25 ml).
The combined organic layers were dried over MgSO4 and
evaporated to dryness. Yield 2.5 g (46%), white powder,
1
(mp 134–135.5°С (CH2Cl2 – petroleum ether)13). H NMR
spectrum, δ, ppm: 1.20–1.32 (20H, (CH2)10); 1.32–1.40
(2H, m, CH2CH2N); 1.45–1.55 (2H, m, CH2CH2CO); 2.02–
2.06 (2H, m, CH2CO); 3.04–3.12 (2H, m, CH2N); 7.72–
7.80 (1H, m, NHCO). Found, %: C 75.26; H 12.21; N 5.85.
C15H29NO. Calculated, %: C 75.43; H 12.43; N 5.81.
15-Aminopentadecanoic acid (2e). A solution of
lactam 6 (4.1 g, 17.1 mmol) in 6 М HCl (150 ml) was
heated under reflux for 19 h. The resulting mixture was
cooled, the formed precipitate was filtered off, suspended
in H2O (100 ml), and pH was adjusted to 6 by the addition
of 5% aqueous NaHCO3. The formed precipitate was
filtered off and washed on the filter with a cooled H2O–
DMSO, 1:1 mixture. Yield 2.6 g (60%), white powder,
mp 180–181°С (mp 180–182°С (MeOH)14). 1H NMR
spectrum, δ, ppm: 1.26–1.42 (20H, m, (CH2)10); 1.57–1.66
(2H, m, CH2CH2N); 1.66–1.74 (2H, m, CH2CH2CO); 2.33–
2.39 (2H, m, CH2CO); 3.02–3.10 (2H, m, CH2N). Found,
%: C 70.16; H 12.01; N 5.32. C15H31NO2. Calculated, %:
C 69.99; H 12.14; N 5.44.
1
mp 43–44°С (mp 41–43°C (EtOAc)12). H NMR spectrum,
δ, ppm (J, Hz): 1.24 (8H, br. s, (CH2)4); 1.45–1.54 (4H, m,
CH2(CH2)4CH2); 2.18 (2H, t, J = 7.4, CH2CO); 2.28 (2H, t,
J = 7.4, CH2CO); 3.58 (3H, s, COOCH3). Found, %:
C 61.04; H 9.55. C11H20O4. Calculated, %: C 61.09;
H 9.32.
9-Aminononanoic acid hydrochloride (2b). (COCl)2
(2.5 ml, 3.67 g, 28.9 mmol) was added to a solution of ester
4 (2.5 g, 11.6 mmol) in CH2Cl2 (20 ml). The reaction
mixture was stirred at room temperature for 6 h, then
evaporated to dryness. The residue was dissolved in
Me2CO (30 ml), and a solution of NaN3 (3.7 g, 56.5 mmol)
in H2O (15 ml) was added to the resulting solution with
cooling and stirring. The reaction mixture was kept at 0°С
for 1 h, then poured into H2O (300 ml) and extracted with
AcOEt (3×25 ml). The combined organic layers were dried
Synthesis of compounds 7a,c–e (General method). A
mixture of amino acid 2a,c–e (10 mmol) and PhthO (1.5 g,
10 mmol) was heated at 180°C for 2 h. The reaction
mixture was cooled, treated with hexane, the formed
precipitate was filtered off and recrystallized from H2O–
EtOH, 1:1.
7-Phthalimidoheptanoic acid (7a). Yield 2.6 g (89%),
white powder, mp 117–118°С (H2O–EtOH) (mp 115–118°С
1
(H2O–EtOH)15). H NMR spectrum, δ, ppm: 1.20–1.35
(4H, m, (CH2)2); 1.41–1.51 (2H, m, CH2CH2N); 1.52–1.63
(2H, m, CH2CH2CO); 2.13–2.21 (2H, m, CH2CO); 3.52–
3.59 (2H, m, CH2N); 7.80–7.90 (4H, m, Н phthalimide);
11.96 (1H, s, COOH). Found, %: C 65.49; H 6.53; N 5.06.
C15H17NO4. Calculated, %: C 65.44; H 6.22; N 5.09.
493

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
11-Phthalimidoundecanoic acid (7с). Yield 2.8 g
column chromatography on SiO2 (eluent hexane–AcOEt,
(84%), white powder, mp 89–90°С (H2O–EtOH) (mp 86–
65:35 or PhH – AcOEt, 95: 5).
1
88°С (H2O–EtOH)15). H NMR spectrum, δ, ppm: 1.17–
7,8-Difluoro-3-methyl-4-(7-phthalimidoheptanoyl)-
1.31 (12H, m, (CH2)6); 1.40–1.52 (2H, m, CH2CH2N); 1.52–
1.63 (2H, m, CH2CH2CO); 2.13–2.21 (2H, m, CH2CO);
3.52–3.59 (2H, m, CH2N); 7.80–7.90 (4H, m, Н phthalimide);
11.95 (1H, s, COOH). Found, %: C 68.96; H 7.52; N 4.45.
C19H25NO4. Calculated, %: C 68.86; H 7.60; N 4.23.
3,4-dihydro-2H-1,4-benzoxazine (10a). Yield 1.2 g
1
(71%), white powder, mp 93–94°С. H NMR spectrum,
δ, ppm (J, Hz): 1.11 (3H, d, J = 6.9, CH3); 1.25–1.40 (4H,
m, CH2CH2); 1.54–1.66 (4H, m, CH2(CH2)2CH2); 2.41–
2.51 (1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.58 (1H, dt, J = 16.0, J = 7.3, CH2O); 3.54–
3.61 (2H, m, CH2N); 4.13 (1H, dd, J = 11.0, J = 2.8,
2-СH2); 4.32 (1H, dd, J = 11.0, J = 1.5, 2-СH2); 4.72 (1H,
qdd, J = 6.9, J = 2.8, J = 1.5, 3-CH); 6.83 (1H, ddd,
J = 9.9, J = 9.9, J = 8.2, H-6); 7.50–7.58 (1H, m, H-5);
7.77–7.84 (4H, m, Н phthalimide). 13C NMR spectrum,
δ, ppm (J, Hz): 15.1; 24.5; 26.0; 27.7; 28.1; 33.3; 37.3;
44.9; 69.8; 106.7 (d, J = 17.9); 119.2; 121.8; 122.9 (2С);
131.5 (2С); 134.3 (2С); 135.6 (d, J = 7.9); 138.9 (dd,
J = 243.2, J = 15.4); 146.4 (d, J = 242.0); 167.9 (2С);
170.9. 19F NMR spectrum, δ, ppm (J, Hz): 1.97 (1F, ddd,
J = 21.0, J = 8.2, J = 2.2, F-8); 20.00–20.15 (1F, m, F-7).
Found, %: C 65.03; H 5.61; F 8.68; N 6.32. C24H24F2N2O4.
Calculated, %: C 65.15; H 5.47; F 8.59; N 6.33.
12-Phthalimidododecanoic acid (7d). Yield 1.7 g
(48%), white powder, mp 93–94°С (H2O–EtOH) (mp 90–
1
92°С (СH2Cl2)16). H NMR spectrum, δ, ppm: 1.18–1.30
(14H, m, (CH2)7); 1.40–1.52 (2H, m, CH2CH2N); 1.52–
1.63 (2H, m, CH2CH2CO); 2.14–2.20 (2H, m, CH2CO);
3.51–3.59 (2H, m, CH2N); 7.80–7.90 (4H, m, Н phthalimide);
11.95 (1H, s, COOH). Found, %: C 69.54; H 7.81; N 3.91.
C20H27NO4. Calculated, %: C 69.54; H 7.88; N 4.05.
15-Phthalimidopentadecanoic acid (7e). Yield 2.8 g
(71%), white powder, mp 95–96°С (H2O–EtOH). 1H NMR
spectrum, δ, ppm: 1.16–1.30 (20H, m, (CH2)10); 1.42–1.52
(2H, m, CH2CH2N); 1.52–1.63 (2H, m, CH2CH2CO); 2.13–
2.22 (2H, m, CH2CO); 3.52–3.59 (2H, m, CH2N); 7.80–
7.90 (4H, m, Н phthalimide); 11.96 (1H, s, COOH).
13C NMR spectrum, δ, ppm: 24.5; 26.2; 27.8; 28.4; 28.5;
28.7; 28.8; 28.9 (2С); 29.0 (3C); 33.6; 37.3; 122.9 (2С);
131.6 (2С); 134.3 (2С); 167.9 (2С); 174.5. Found, %:
C 71.37; H 8.81; N 3.75. C23H33NO4. Calculated, %:
C 71.29; H 8.58; N 3.61.
9-Phthalimidononanoic acid (7b). Et3N (1.1 ml, 0.80 g,
7.87 mmol) and PhthO (1.1 g, 7.15 mmol) were added to a
suspension of amino acid hydrochloride 2b (1.5 g, 7.15 mmol)
in PhMe (25 ml). The reaction mixture was heated under
reflux with stirring for 2 h, then cooled and evaporated.
The residue was recrystallized from the H2O–EtOH
mixture. Yield 0.9 g (41%), white powder, mp 89–90°С
(H2O–EtOH) (mp 82–83°С (H2O–EtOH)15). 1H NMR
spectrum, δ, ppm: 1.20–1.30 (8H, m, (CH2)4); 1.41–1.52
(2H, m, CH2CH2N); 1.52–1.62 (2H, m, CH2CH2CO); 2.13–
2.20 (2H, m, CH2CO); 3.52–3.58 (2H, m, CH2N); 7.80–
7.89 (4H, m, Н phthalimide); 11.96 (1H, s, COOH). Found,
%: C 67.38; H 7.00; N 4.88. C17H21NO4. Calculated, %:
C 67.31; H 6.98; N 4.62.
Synthesis of compounds 8a–e (General method).
(COCl)2 (2.1 ml, 3.17 g, 25 mmol) was added to a solution
of N-phthaloylamino acid 7а–е (10 mmol) in CH2Cl2
(20 ml). The reaction mixture was stirred at room tempera-
ture for 6 h, then evaporated to dryness. The residue was
triturated with dry hexane, filtered, and used without
additional purification in subsequent transformations.
Synthesis of compounds 10a–e (General method). A
solution of acyl chloride 8a–e (3.90 mmol) in CH2Cl2
(20 ml) was added to a solution of 7,8-difluoro-3-methyl-
3,4-dihydro-2H-1,4-benzoxazine (9) (0.72 g, 3.90 mmol)
and N,N-diethylaniline (630 μl, 582 mg, 3.90 mmol) in
CH2Cl2 (20 ml). The reaction mixture was stirred at room
temperature for 2 days, then washed with 4 M HCl (3×5 ml),
saturated aqueous NaCl (5×10 ml), 5% aqueous NaHCO3
(3×10 ml), and H2O (3×10 ml). The organic layer was
separated, dried over MgSO4, and evaporated to dryness
under reduced pressure. The residue was purified by
7,8-Difluoro-3-methyl-4-(9-phthalimidononanoyl)-
3,4-dihydro-2H-1,4-benzoxazine (10b). Yield 1.1 g (62%),
1
white powder, mp 79–80°С. H NMR spectrum, δ, ppm
(J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.23–1.35 (8H, m,
(CH2)4); 1.52–1.68 (4H, m, CH2(CH2)4CH2); 2.41–2.48
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.57 (1H, dt, J = 15.9, J = 7.5, CH2CO); 3.50–
3.62 (2H, m, CH2N); 4.13 (1H, dd, J = 11.0, J = 2.8,
2-СH2); 4.33 (1H, dd, J = 10.9, J = 1.5, 2-СH2); 4.73 (1H,
qdd, J = 6.9, J = 2.8, J = 1.4, 3-CH); 6.84 (1H, ddd,
J = 9.8, J = 9.8, J = 8.3, H-6); 7.52–7.58 (1H, m, H-5); 7.78–
7.84 (4H, m, Н phthalimide). 13C NMR spectrum, δ, ppm
(J, Hz): 15.1; 24.6; 26.1; 27.8; 28.4; 28.5; 28.6; 33.4; 37.3;
44.8; 69.8; 106.7 (d, J = 17.9); 119.2; 121.8; 122.9 (2С);
131.5 (2С); 134.3 (2С); 135.7 (d, J = 7.9); 138.9 (dd,
J = 243.2, J = 15.4); 146.5 (d, J = 242.0); 167.8 (2С);
170.9. 19F NMR spectrum, δ, ppm (J, Hz): 1.97 (1F, ddd,
J = 21.0, J = 8.2, J = 2.3, F-8); 20.00–20.18 (1F, m, F-7).
Found, %: C 66.32; H 5.97; F 8.04; N 5.92. C26H28F2N2O4.
Calculated, %: C 66.37; H 6.00; F 8.08; N 5.95.
7,8-Difluoro-3-methyl-4-(11-phthalimidoundecanoyl)-
3,4-dihydro-2H-1,4-benzoxazine (10c). Yield 1.3 g (65%),
1
white powder, mp 87–88°С. H NMR spectrum, δ, ppm
(J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.20–1.35 (12H, m,
(CH2)6); 1.52–1.66 (4H, m, CH2(CH2)6CH2); 2.42–2.48
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.57 (1H, dt, J = 15.9, J = 7.3, CH2CO); 3.54–
3.60 (2H, m, CH2N); 4.13 (1H, dd, J = 10.9, J = 2.8,
2-СH2); 4.33 (1H, dd, J = 10.9, J = 1.5, 2-СH2); 4.73 (1H,
qdd, J = 7.0, J = 2.8, J = 1.5, 3-СH); 6.84 (1H, ddd,
J = 9.9, J = 9.8, J = 8.2, H-6); 7.52–7.58 (1H, m, H-5);
7.76–7.86 (4H, m, Н phthalimide). 13C NMR spectrum,
δ, ppm (J, Hz): 15.1; 24.6; 26.1; 27.8; 28.4; 28.5; 28.6;
33.4; 37.3; 44.8; 69.8; 106.7 (d, J = 17.9); 119.2; 121.8;
122.9 (2С); 131.5 (2С); 134.3 (2С); 135.7 (d, J = 7.8);
138.9 (dd, J = 243.3, J = 15.4); 146.5 (d, J = 242.5); 167.8
(2С); 170.9. 19F NMR spectrum, δ, ppm (J, Hz): 1.97 (1F,
494

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
ddd, J = 20.9, J = 8.2, J = 2.4, F-8); 20.00–20.15 (1F, m,
solution (5×10 ml), H2O (3×10 ml) and evaporated to
dryness under reduced pressure. The residue was purified
by column chromatography on SiO2 (eluent CHCl3–EtOH).
7,8-Difluoro-3-methyl-4-[7-(purin-6-ylamino)heptanoyl]-
3,4-dihydro-2H-1,4-benzoxazine (12a). Yield 0.54 g (62%),
light-yellow powder, mp 93–94°С. 1H NMR spectrum, δ, ppm
(J, Hz): 1.11 (3H, d, J = 6.8, CH3); 1.33–1.42 (4H, m,
CH2CH2); 1.55–1.67 (4H, m, CH2(CH2)2CH2); 2.42–2.50
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.54–2.63 (1H, m, CH2CO); 3.53–3.61 (2H, m,
CH2NH); 4.13 (1H, dd, J = 10.9, J = 2.8, 2-СH2); 4.33
(1H, dd, J = 10.9, J = 1.5, 2-СH2); 4.73 (1H, qdd, J = 6.9,
J = 2.8, J = 1.5, 3-СH); 6.83 (1H, ddd, J = 9.9, J = 9.8,
J = 8.3, H-6); 7.10 (1Н, br. s, CH2NH); 7.52–7.58 (1H, m,
H-5); 7.98 (1H, s, H-8 purine); 8.16 (1H, s, H-2 purine).
13C NMR spectrum, δ, ppm (J, Hz): 15.1; 24.6; 26.2; 28.3;
29.0; 33.4; 40.3 (overlaps with the signal of DMSO-d6);
45.0; 69.8; 106.7 (d, J = 17.9); 117.4; 119.2; 121.8; 135.7
(d, J = 7.9); 138.9 (dd, J = 243.2, J = 15.3); 139.1; 146.5
(d, J = 238.3); 150.0; 151.8; 153.8; 171.0. 19F NMR
spectrum, δ, ppm (J, Hz): 1.99 (1F, ddd, J = 21.0, J = 8.2,
J = 2.3, F-8); 20.00–20.15 (1F, m, F-7). Found, %:
C 58.40; H 5.70; F 8.78; N 19.24. C21H24F2N2O2.
Calculated, %: C 58.60; H 5.62; F 8.83; N 19.52.
F-7). Found, %: C 67.25; H 6.70; F 7.31; N 5.51.
C28H32F2N2O4. Calculated, %: C 67.45; H 6.47; F 7.62; N 5.62.
7,8-Difluoro-3-methyl-4-(12-phthalimidododecanoyl)-
3,4-dihydro-2H-1,4-benzoxazine (10d). Yield 1.4 g (70%),
1
white powder, mp 63–64°С. H NMR spectrum, δ, ppm
(J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.20–1.33 (14H, m,
(СH2)7); 1.53–1.65 (4H, m, CH2(CH2)7CH2); 2.43–2.50
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.57 (1H, dt, J = 15.6, J = 7.3, CH2CO); 3.43–
3.60 (2H, m, CH2N); 4.13 (1H, dd, J = 10.9, J = 2.9,
2-CH2); 4.33 (1H, dd, J = 10.9, J = 1.4, 2-CH2); 4.74 (1H,
qdd, J = 6.9, J = 2.7, J = 1.5, 3-CH); 6.84 (1H, ddd,
J = 9.8, J = 9.7, J = 8.3, H-6); 7.52–7.60 (1H, m, H-5);
7.77–7.85 (4H, m, Н phthalimide). 13C NMR spectrum,
δ, ppm (J, Hz): 15.1; 24.6; 26.1; 27.8; 28.4; 28.5; 28.7
(2C); 28.8 (2С); 33.4; 37.3; 44.9; 69.8; 106.7 (d, J = 17.9);
119.2; 121.8; 122.9 (2С); 131.5 (2С); 134.3 (2С); 135.7
(dd, J = 9.7, J = 2.5); 138.9 (dd, J = 243.3, J = 15.4); 146.5
(d, J = 241.9); 167.8 (2С); 171.0. 19F NMR spectrum, δ, ppm
(J, Hz): 1.97 (1F, ddd, J = 21.1, J = 8.2, J = 2.3, F-8);
20.02–20.16 (1F, m, F-7). Found, %: C 67.89; H 6.64;
F 7.50; N 5.26. C29H34F2N2O4. Calculated, %: C 67.95;
H 6.69; F 7.41; N 5.47.
7,8-Difluoro-3-methyl-4-(15-phthalimidopentadecanoyl)-
3,4-dihydro-2H-1,4-benzoxazine (10e). Yield 1.3 g (60%),
white powder, mp 86–87°С. H NMR spectrum, δ, ppm
7,8-Difluoro-3-methyl-4-[9-(purin-6-ylamino)nonano-
yl]-3,4-dihydro-2H-1,4-benzoxazine (12b). Yield 0.25 g
(44%), light-yellow powder, mp 74–75°С. 1H NMR
spectrum, δ, ppm (J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.22–
1.40 (8H, m, (CH2)4); 1.52–1.68 (4H, m, CH2(CH2)4CH2);
2.42–2.48 (1H, m, CH2CO, partially overlaps with the
signal of DMSO-d6); 2.52–2.62 (1H, m, CH2CO); 3.52–
3.60 (2H, m, CH2NH); 4.13 (1H, dd, J = 10.9, J = 2.9,
2-СH2); 4.33 (1H, dd, J = 10.9, J = 1.4, 2-СH2); 4.74 (1H,
qdd, J = 6.9, J = 2.8, J = 1.4, 3-СH); 6.84 (1H, ddd,
J = 9.8, J = 9.8, J = 8.3, H-6); 7.04 (1Н, br. s, CH2NH);
7.52–7.58 (1H, m, H-5); 7.97 (1H, s, H-8 purine); 8.15
(1H, s, H-2 purine). 13C NMR spectrum, δ, ppm (J, Hz):
15.1; 24.6; 26.3; 28.5; 28.7; 28.8; 29.1; 33.4; 40.3
(overlaps with the signal of DMSO-d6); 45.0; 69.9; 106.8
(d, J = 17.9); 117.6; 119.3; 121.8; 135.7 (d, J = 8.3); 138.9
(dd, J = 243.3, J = 15.4); 139.0; 146.4 (d, J = 242.4);
150.1; 151.9; 153.8; 171.0. 19F NMR spectrum, δ, ppm:
1.94–2.04 (1F, m, F-8); 20.00–20.16 (1F, m, F-7). Found,
%: C 60.33; H 6.35; F 8.51; N 18.58. C23H28F2N6O2.
Calculated, %: C 60.25; H 6.16; F 8.29; N 18.33.
1
(J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.20–1.34 (20H, m,
(CH2)10); 1.54–1.65 (4H, m, CH2(CH2)10CH2); 2.42–2.50
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.57 (1H, dt, J = 15.8, J = 7.2, CH2CO); 3.54–
3.60 (2H, m, CH2N); 4.13 (1H, dd, J = 10.9, J = 3.0,
2-СH2); 4.33 (1H, dd, J = 10.9, J = 1.5, 2-СH2); 4.74 (1H,
qdd, J = 6.8, J = 2.7, J = 1.5, 3-СH); 6.84 (1H, ddd,
J = 9.8, J = 9.8, J = 8.3, H-6); 7.52–7.58 (1H, m, H-5);
7.78–7.85 (4H, m, Н phthalimide). 13C NMR spectrum,
δ, ppm (J, Hz): 15.1; 24.6; 26.1; 27.8; 28.4; 28.5; 28.7
(2С); 28.8 (2С); 28.9 (3С); 33.4; 37.3; 44.7; 69.9; 106.7 (d,
J = 17.9); 119.2; 121.8; 122.9 (2С); 131.5 (2С); 134.3
(2С); 135.7 (d, J = 8.5); 138.9 (dd, J = 243.4, J = 15.4);
146.5 (d, J = 239.3); 167.9 (2С); 171.0. 19F NMR spectrum,
δ, ppm (J, Hz): 1.99 (1F, ddd, J = 21.0, J = 8.3, J = 2.3,
F-8); 20.00–20.18 (1F, m, F-7). Found, %: C 69.37;
H 7.39; F 6.78; N 4.84. C32H40F2N2O4. Calculated, %:
C 69.29; H 7.27; F 6.85; N 5.05.
Synthesis of compounds 12a–e (General method). To a
solution of compound 10a–e (1.91 mmol) in EtOH (14 ml),
H2N–NH2·H2O (170 μl, 172 mg, 3.43 mmol) was added.
The reaction mixture was heated under reflux for 2 h, then
evaporated to dryness. Et2O (25 ml) was added to the
residue and kept at –16°C for 12 h. The resulting
precipitate was filtered off and washed with Et2O (3×3 ml).
The mother liquor was evaporated to dryness and the
residue was dissolved in n-BuOH (4 ml). 6-Chloropurine
(0.12 g, 0.80 mmol) and Et3N (190 μl, 137 mg, 1.35 mmol)
in n-BuOH (4 ml) were added to the solution. The reaction
mixture was heated at 90°C for 10 h. After cooling,
n-BuOH (12 ml) was added, the resulting solution was
washed with 1 M HCl (3×5 ml), saturated aqueous NaCl
7,8-Difluoro-3-methyl-4-[11-(purin-6-ylamino)undecano-
yl]-3,4-dihydro-2H-1,4-benzoxazine (12c). Yield 0.29 g
(47%), light-yellow powder, mp 74–75°С. 1H NMR spectrum,
δ, ppm (J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.22–1.38 (12H,
m, (CH2)6); 1.52–1.66 (4H, m, CH2(CH2)6CH2); 2.42–2.48
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.52–2.62 (1H, m, CH2CO); 3.52–3.60 (2H, m,
CH2NH); 4.13 (1H, dd, J = 10.9, J = 2.9, 2-СH2); 4.33 (1H,
dd, J = 10.9, J = 1.4, 2-СH2); 4.74 (1H, qdd, J = 6.8,
J = 2.7, J = 1.4, 3-СH); 6.84 (1H, ddd, J = 9.8, J = 9.8,
J = 8.3, H-6); 6.94 (1Н, br. s, CH2NH); 7.53–7.58 (1H, m,
H-5); 7.95 (1H, s, H-8 purine); 8.15 (1H, s, H-2 purine),
12.42 (1Н, br. s, 9-NH purine). 13C NMR spectrum, δ, ppm
(J, Hz): 15.1; 24.6; 26.4; 28.5; 28.7 (2C); 28.8; 28.9; 29.1;
495

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
33.4; 39.5 (overlaps with the signal of DMSO-d6); 44.6;
1188 μM; it was then diluted to a concentration of about
9.28 μM, then the cells were infected with the virus at a
multiplicity of infection of ~0.1 PFU/cell. The infected
cells were incubated in a humidified atmosphere with 5%
CO2 at 37°C for 48 h, after which the antiviral effect of the
compounds was evaluated, expressed as the concentration
at which the CPE is reduced by 50% (ID50). To assess the
cytotoxicity of the synthesized compounds, the percentage
of viable cells was determined by trypan blue staining.
69.9; 106.7 (d, J = 17.9); 118.6; 119.2; 121.8; 135.7 (dd,
J = 9.7, J = 2.5); 138.4; 138.9 (dd, J = 243.4, J = 15.4);
146.5 (d, J = 242.5); 149.3; 152.3; 154.5; 171.0. 19F NMR
spectrum, δ, ppm (J, Hz): 1.98 (1F, ddd, J = 21.0, J = 8.2,
J = 2.4, F-8); 20.02–20.16 (1F, m, F-7). Found, %:
C 60.33; H 6.35; F 8.51; N 18.58. C23H28F2N6O2.
Calculated, %: C 60.25; H 6.16; F 8.29; N 18.33.
7,8-Difluoro-3-methyl-4-[12-(purin-6-ylamino)dodecano-
yl]-3,4-dihydro-2H-1,4-benzoxazine (12d). Yield 0.42 g
(66%), light-yellow powder, mp 62–63°С. 1H NMR spectrum,
δ, ppm (J, Hz): 1.12 (3H, d, J = 6.9, CH3); 1.20–1.40 (14H,
m, (CH2)7); 1.53–1.65 (4H, m, CH2(CH2)7CH2); 2.42–2.50
(1H, m, CH2CO, partially overlaps with the signal of
DMSO-d6); 2.53–2.62 (1H, m, CH2CO); 3.51–3.62 (2H, m,
CH2NH); 4.13 (1H, dd, J = 10.9, J = 2.7, 2-СH2); 4.33
(1H, d, J = 11.0, 2-СH2); 4.70–4.78 (1H, m, 3-СH); 6.84
(1H, ddd, J = 9.8, J = 9.7, J = 8.4, H-6); 6.94 (1Н, br. s,
CH2NH); 7.50–7.60 (1H, m, H-5); 7.94 (1H, s, H-8 purine);
8.14 (1H, s, H-2 purine), 12.49 (1Н, br. s, 9-NH purine).
13C NMR spectrum, δ, ppm (J, Hz): 15.1; 24.6; 26.4; 28.5;
28.8 (2C); 28.9 (2C); 29.0; 29.1; 33.4; 40.0 (overlaps with
the signal of DMSO-d6); 44.7; 69.9; 106.8 (d, J = 17.9);
118.7; 119.3; 121.8; 135.7 (d, J = 8.4); 138.4; 138.9 (dd,
J = 243.4, J = 15.4); 146.5 (d, J = 240.4); 149.3; 152.3;
154.4; 171.0. 19F NMR spectrum, δ, ppm (J, Hz): 1.98 (1F,
ddd, J = 21.0, J = 8.3, J = 1.9, F-8); 20.00–20.20 (1F, m,
F-7). Found, %: C 62.29; H 6.75; F 7.51; N 17.01.
C26H34F2N6O2. Calculated, %: C 62.38; H 6.85; F 7.59;
N 16.79.
7,8-Difluoro-3-methyl-4-[15-(purin-6-ylamino)penta-
decanoyl]-3,4-dihydro-2H-1,4-benzoxazine hydrate (12e).
Yield 0.32 g (46%), light-yellow powder, mp 65–66°С.
1H NMR spectrum, δ, ppm (J, Hz): 1.12 (3H, d, J = 6.9,
CH3); 1.20–1.40 (20H, m, (CH2)10); 1.52–1.70 (4H, m,
CH2(CH2)10CH2); 2.40–2.50 (1H, m, CH2CO, partially
overlaps with the signal of DMSO-d6); 2.53–2.63 (1H, m,
CH2CO); 3.55–3.65 (2H, m, CH2NH); 4.13 (1H, dd, J = 11.0,
J = 2.8, 2-СH2); 4.33 (1H, dd, J = 10.9, J = 1.4, 2-СH2);
4.74 (1H, qdd, J = 6.9, J = 2.6, J = 1.4, 3-СH); 6.84 (1H,
ddd, J = 9.8, J = 9.8, J = 8.3, H-6); 7.50–7.58 (1H, m,
H-5); 7.61 (1Н, br. s, CH2NH); 8.08 (1H, s, H-8 purine);
8.23 (1H, s, H-2 purine). 13C NMR spectrum, δ, ppm
(J, Hz): 15.1; 24.6; 26.3; 28.5; 28.7; 28.8; 28.9 (6С); 33.4;
40.3 (overlaps with the signal of DMSO-d6); 44.8; 69.9;
106.8 (d, J = 17.9); 116.3; 119.3; 121.8; 135.7 (d, J = 8.6);
139.0 (dd, J = 243.4, J = 15.4); 140.0; 146.5 (d,
J = 239.3); 149.4; 150.5; 153.0; 171.0. 19F NMR spectrum,
δ, ppm (J, Hz): 2.00 (1F, ddd, J = 21.0, J = 8.2, J = 2.2,
F-8); 20.00–20.22 (1F, m, F-7). Found, %: C 63.81;
This work was carried out with financial support from
the Russian Science Foundation (grant 19-13-00231) using
the equipment of the Center for Collective Use
''Spectroscopy and Analysis of Organic Compounds'' at the
Postovsky Institute of Organic Synthesis of the Ural
Branch of the Russian Academy of Sciences.
References
1. Herpes Simplex Virus; WHO Fact Sheet. https://
www.who.int/news-room/fact-sheets/detail/herpes-simplex-
virus, 2020.
2. Suzich, J. B.; Cliffe, A. R. Virology 2018, 522, 81.
3. Andrei, G.; Georgala, A.; Topalis, D.; Fiten, P.; Aoun, M.;
Opdenakker, G.; Snoeck R. J. Infect. Dis. 2013, 207, 1295.
4. (a) Brady, R. C.; Bernstein, D. I. Antiviral Res. 2004, 61, 73.
(b) Kukhanova, M. K.; Korovina, A. N.; Kochetkov, S. N.
Biochemistry (Moscow) 2014, 79, 1635. [Usp. Biol. Khimii
2014, 54, 457.]
5. Piret, J.; Boivin, G. Antimicrob. Agents Chemother. 2011, 55,
459.
6. (a) Vigorov, A. Yu.; Krasnov, V. P.; Gruzdev, D. A.;
Men'shikova, A. A.; Demin, A. M.; Levit, G. L.; Charushin, V. N.
Mendeleev Commun. 2014, 24, 35. (b) Gruzdev, D. A.;
Musiyak, V. V.; Chulakov, E. N.; Levit, G. L.; Krasnov, V. P.
Chem. Heterocycl. Compd. 2015, 51, 738. [Khim. Geterotsikl.
Soedin. 2015, 51, 738.] (c) Krasnov, V. P.; Gruzdev, D. A.;
Chulakov, E. N.; Vigorov, A. Yu.; Musiyak, V. V.; Matveeva, T. V.;
Tumashov, A. A.; Levit, G. L.; Charushin, V. N. Mendeleev
Commun. 2015, 25, 412. (d) Eletskaya, B. Z.; Konstantinova, I. D.;
Paramonov, A. S.; Esipov, R. S.; Gruzdev, D. A.; Vigorov, A. Yu.;
Levit, G. L.; Miroshnikov, A. I.; Krasnov, V. P.;
Charushin, V. N. Mendeleev Commun. 2016, 26, 6.
(e) Krasnov, V. P.; Vigorov, A. Yu.; Musiyak, V. V.; Nizova, I. A.;
Gruzdev, D. A.; Matveeva, T. V.; Levit, G. L.; Kravchenko, M. A.;
Skornyakov, S. N.; Bekker, O. B.; Danilenko, V. N.;
Charushin, V. N. Bioorg. Med. Chem. Lett. 2016, 26, 2645.
(f) Gruzdev, D. A.; Chulakov, E. N.; Levit, G. L.;
Kravchenko, M. A.; Krasnov, V. P.; Charushin, V. N.
Mendeleev Commun. 2017, 27, 547. (g) Gruzdev, D. A.;
Musiyak, V. V.; Levit, G. L.; Krasnov, V. P.; Charushin, V. N.
Russ. Chem. Rev. 2018, 87, 604. [Usp. Khim. 2018, 87, 604.]
(h) Musiyak, V. V.; Gruzdev, D. A.; Kravchenko, M. A.,
Vakhrusheva, D. V.; Levit, G. L.; Krasnov, V. P.;
Charushin, V. N. Mendeleev Commun. 2019, 29, 11.
(i) Krasnov, V. P.; Musiyak, V. V.; Vozdvizhenskaya, O. A.;
Galegov, G. A.; Andronova, V. L.; Gruzdev, D. A.;
Chulakov, E. N.; Vigorov, A. Yu.; Ezhikova, M. A.;
Kodess, M. I.; Levit, G. L.; Charushin, V. N. Eur. J. Org.
Chem. 2019, 30, 4811. (j) Krasnov, V. P.; Levit, G. L.;
Musiyak, V. V.; Gruzdev, D. A.; Charushin, V. N. Pure Appl.
Chem. 2020, 92, 1277.
H
7.37;
F
6.67;
N
15.36. C29H40F2N6O2·0.2H2O.
Calculated, %: C 63.76; H 7.45; F 6.96; N 15.38.
Study of cytotoxicity and antiviral activity of
compounds 12a–e was performed for HSV-1/L2 and
HSV-1/L2/R strains in Vero E6 cells by the cytopathogenic
effect (CPE) inhibition assay as previously described.6i
Monolayers of Vero E6 cells in 96-well plates were treated
with twofold serial dilutions of the test compounds in
a supportive medium. The starting concentration was
7. (a) Kalgutkar, A. S.; Crews, B. C.; Marnett, L. J. J. Med.
Chem. 1996, 39, 1692. (b) Haulotte, E.; Laurent, P.;
Braekman, J.-C. Eur. J. Org. Chem. 2012, 10, 1907.
496

Chemistry of Heterocyclic Compounds 2021, 57(4), 490–497
8. (a) Gao, L.; Xia, H.; Wang, X.; Li, L.; Chen, H. Spectrochim.
12. Zav'yalov, S. I.; Kravchenko, N. E. Bull. Acad. Sci. USSR,
Div. Chem. Sci. 1988, 37, 1514. [Izv. Akad. Nauk, Ser. Khim.
1988, 1696.]
13. Nagasawa, H. T.; Elberling, J. A.; Fraser, P. S.; Mizuno, N. S.
J. Med. Chem. 1971, 14, 501.
14. Ballini, R.; Papa, F.; Abate, C. Eur. J. Org. Chem. 1999,
87.
15. Itoh, K.; Kori, M.; Inada, Y.; Nishikawa, K.; Kawamatsu, Y.;
Sugihara H. Chem. Pharm. Bull. 1986, 34, 2078.
16. Tomar, R.; Bhattacharya, D.; Arulananda Babu, S.
Tetrahedron 2019, 75, 2447.
Acta, Part A 2015, 139, 222. (b) Stephens, T. C.; Lodi, M.;
Steer, A. M.; Lin, Y.; Gill, M. T.; Unsworth, W. P. Chem.–
Eur. J. 2017, 23, 13314.
9. Cook, E. S.; Fujii, A.; Tanaka, K.; Tsuchiya, Y. J. Med.
Chem. 1971, 14, 354.
10. Guénin, E.; Monteil, N.; Bouchemal, N.; Prangé, T.;
Lecouvey, M. Eur. J. Org. Chem. 2007, 20, 3380.
11. Charushin, V. N.; Gorbunov, E. B.; Rusinov, G. L.;
Likholobov, V. A.; Rodionov, V. A. RU Patent 2434005;
Chem. Abstr. 2011, 155, 683753.
497