Synthesis, structure, and antibacterial activity of aminobenzofuroxan and aminobenzofurazan

Article abstract of DOI:10.1134/S1070428013040167

The amination of 4,6-dichloro-5,7-dinitrobenzofuroxan and 4,6-dichloro-5,7-dinitrobenzofurazan with dibenzylamine followed the aromatic nucleophilic substitution pattern (S_NAr) and gave products of replacement of both chlorine atoms in the six-membered ring with elimination of hydrogen chloride. Regardless of the reactant ratio, 4,6-dichloro-5,7- dinitrobenzofuroxan was converted into 4,6-bis(dibenzylamino)-5,7- dinitrobenzofuroxan, whereas 4,6-dichloro-5,7-dinitrobenzofurazan under analogous conditions gave rise to unusual bisammonium derivative which lost proton from the amino group on C⁴ and benzyl group from the amino group on C⁶; as a result, the corresponding diamine with secondary and tertiary nitrogen atoms was obtained. The structure of the isolated compounds was determined by IR and NMR spectroscopy, elemental analysis, and X-ray analysis; their thermal stability was studied by simultaneous thermogravimetry and differential scanning calorimetry.

Full text of DOI:10.1134/S1070428013040167

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 4, pp. 591–597. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © I.V. Galkina, G.L. Takhautdinova, E.V. Tudrii, L.M. Yusupova, I.F. Falyakhov, O.K. Pozdeev, M.P. Shulaeva, L.V. Kipenskaya,
V.G. Sakhibullina, D.B. Krivolapov, I.A. Litvinov, V.I. Galkin, R.A. Cherkasov, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 4,
pp. 607–613.
Dedicated to the 100th Anniversary of Corresponding Member
of the Russian Academy of Sciences A.A. Petrov
Synthesis, Structure, and Antibacterial Activity
of Aminobenzofuroxan and Aminobenzofurazan
I. V. Galkinaa, G. L. Takhautdinovaa, E. V. Tudriia, L. M. Yusupovab, I. F. Falyakhovb,
O. K. Pozdeevc, M. P. Shulaevac, L. V. Kipenskayac, V. G. Sakhibullinaa, D. B. Krivolapovd,
I. A. Litvinovd, V. I. Galkina, and R. A. Cherkasova
a Kazan (Volga Region) Federal University, ul. Kremlevskaya 18, Kazan, 420008 Tatarstan, Russia
e-mail: vig54@mail.ru
b Kazan National Research Technological University, ul. K. Marksa 68, Kazan, 420015 Tatarstan, Russia
c Kazan State Medical Academy, ul. Mushtari 11, Kazan, 420012 Tatarstan, Russia
d Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center, Russian Academy of Sciences,
ul. Arbuzova 8, Kazan, 420088 Tatarstan, Russia
Received March 6, 2013
Abstract—The amination of 4,6-dichloro-5,7-dinitrobenzofuroxan and 4,6-dichloro-5,7-dinitrobenzofurazan
with dibenzylamine followed the aromatic nucleophilic substitution pattern (SNAr) and gave products of
replacement of both chlorine atoms in the six-membered ring with elimination of hydrogen chloride. Regard-
less of the reactant ratio, 4,6-dichloro-5,7-dinitrobenzofuroxan was converted into 4,6-bis(dibenzylamino)-5,7-
dinitrobenzofuroxan, whereas 4,6-dichloro-5,7-dinitrobenzofurazan under analogous conditions gave rise to
unusual bisammonium derivative which lost proton from the amino group on C4 and benzyl group from the
amino group on C6; as a result, the corresponding diamine with secondary and tertiary nitrogen atoms was
obtained. The structure of the isolated compounds was determined by IR and NMR spectroscopy, elemental
analysis, and X-ray analysis; their thermal stability was studied by simultaneous thermogravimetry and dif-
ferential scanning calorimetry.
DOI: 10.1134/S1070428013040167
Benzofuroxans and benzofurazans exhibit a broad
spectrum of biological activity [1–11] and are nitrogen
oxide donors [1–5]. They may be regarded as prodrugs
whose biological activity develops through a series of
intermediates inside cells [6–11]. In recent years, much
effort was made by researchers in various fields to find
biologically active compounds among benzofurazan
and benzofuroxan derivatives, taking into account their
structural similarity to nucleic acid bases such as
adenine, guanine, 6-methylaminopurine, 6-dimethyl-
aminopurine, and others. With a view to discover new
pharmacologically active compounds with a broad
spectrum of biological activity in the series of purine
base analogs we examined reactions of dichlorodinitro-
substituted benzofuroxan and benzofurazan with di-
benzylamine. There are no published data on nucleo-
philic substitution in the benzofuroxan or benzofurazan
ring with dibenzylamine, though we believe that intro-
duction of pharmacophoric benzylamino groups into
benzofurazan and benzofuroxan molecules may be
promising from the viewpoint of obtaining new phar-
maceuticals. We previously reported on reactions of
triphenylphosphine with various chloronitrobenzo-
furoxans and chloronitrobenzofurazans; these reactions
involved both chloro and nitro substituents and led
to phosphorylation products which showed high and
diverse pharmacological activity [12–20].
The present article describes the results of our study
on the reactions of 4,6-dichloro-5,7-dinitrobenzofur-
oxan (I) and 4,6-dichloro-5,7-dinitrobenzofurazan (II)
with dibenzylamine in ethanol–diethyl ether (3:1).
Furoxan I reacted with 4 equiv of dibenzylamine at
591

GALKINA et al.
592
Scheme 1.
Cl
N(CH2Ph)2
O2N
Cl
O2N
N
N
N
O
N
EtOH–Et2O
O
+ 4(PhCH2)2NH
+ 2(PhCH2)2NH·HCl
(PhCH2)2N
O
O
NO2
NO2
I
III
IV
by essentially distorted geometry; deviations of atoms
from the mean-square plane were 0.267(5) (C4),
–0.372(5) (C5), and 0.238(5) Å (C7); the five-mem-
bered ring N1O2N3C3aC7a together with the adjacent C4
and C7 atoms is planar within 0.040(5) Å, and the C5
and C6 atoms deviate from that plane toward one side
but by different distances, –0.959(5) and –0.662(5) Å,
respectively. Thus the benzene ring is distorted to form
a flattened unsymmetrical boat. The benzene ring
taken separately is also nonplanar, the C4 and C5 atoms
deviate from the mean-square plane by 0.234(5) and
–0.214(5) Å, respectively, and the nitrogen atoms of
the substituents (nitro and dibenzylamino groups) devi-
ate from that plane by 0.790(4) (N8), –1.218(5) (N5),
0.059(4) (N23), and 1.094(5) Å (N7), i.e., the nitrogen
atoms in the nitro group decline to a stronger extent
than the amino nitrogen atoms. Despite steric hin-
drances, all nitrogen atoms in the substituents are
trigonal, and their bond planes almost coincide with
room temperature to give red crystalline compound III
and dibenzylammonium chloride (IV) (Scheme 1).
The IR spectrum of bis(dibenzylamino)benzofur-
oxan III contained absorption bands typical of benzo-
furoxan ring at 1624 (C=N), 1523 (NO2), and 980 cm–1
(N–O); no NH stretching vibration band was present at
about 3300 cm–1. The purity and high thermal stability
of diamine III (up to 159.7°C) were proved by simul-
taneous thermogravimetry and differential scanning
calorimetry (TGA/DSC; Fig. 1). Melting of a sample
of III (8.372 mg) under argon was accompanied by
decomposition in the temperature range from 174.1 to
188.0°C with strong heat evolution (903.2 J/g). The
weight loss at 300°C was 65.25%.
The X-ray diffraction data for compound III con-
firmed replacement of both chlorine atoms in the ben-
zene ring by dibenzylamino groups (Fig. 2). The ben-
zofuroxan fragment in molecule III was characterized
DSC,
DTG,
TG, %
mW/mg %/min
Weight loss 4.48%
100
Start: 159.7°C
00–0
0–0
End: 188.0°C
90
Area: –903.2 J/mg
0–50
–100
–150
–200
–250
0–5
–10
–15
–20
80
70
60
50
40
Start: 174.1°C
Weight loss 60.78%
Peak: 178.5°C
50
100
150
200
Temperature, °C
250
300
Fig. 1. Simultaneous TG/DSC curves for compound III.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

SYNTHESIS, STRUCTURE, AND ANTIBACTERIAL ACTIVITY
593
the planes formed by the bonds at the corresponding
C14
C15
C13
C12
carbon atoms in the benzene ring: the torsion angles
are as follows: C9N8C4C3a –0.6(7), C24N23C6C5
–27.0(6), C4C5N5O51 –4.8(7), C6C7N7O72 10.5(7)°. The
dibenzylamino group on C6 is turned through a slightly
larger angle since it is located between two nitro
groups. Presumably, the large deviation of the nitro
group on C5 is also determined by steric factor, i.e.,
extrusion by two bulky substituents. However, the
C5–N5 and C7–N7 bond lengths are equal within the
experimental error and are 1.424(5) and 1.437(6) Å,
respectively. By contrast, the C4–N8 and C6–N24 bond
lengths are appreciably different [1.312(5) and
1.338(5) Å, respectively], and the longer bond is that
with the nitrogen atom whose bond plane is consider-
ably turned with respect to the benzene ring. Probably,
conjugation between the substituents and π-system of
the benzene ring or multiple bonds dominates over
bond twisting, i.e., conjugation with the amino and
nitro groups is retained despite distorted planarity of
the benzene ring. The bonds in the benzene ring
(Table 1) are appreciably longer than standard C=Carom
bond (1.395 Å). The benzyl fragments are charac-
terized by usual geometric parameters.
C10
N8
C11
C9
C4
N3
O2
N1
C16
C17
C3a
C7
C22
O51
N5
O52
C24
O1
C21
C5
C6
C7a
C20
C18
O71
C19
O72
N7
C25
N23
C31
C26
C30
C37
C32
C33
C34
C27
C29
C36
C35
C28
Fig. 2. Structure of the molecule of 4,6-bis(dibenzylamino)-
5,7-dinitro-2,1,3-benzoxadiazole 1-oxide (III) according to
the X-ray diffraction data.
The use of 4 equiv of dibenzylamine in the reaction
with benzofuroxan I is necessary to bind two hydrogen
chloride molecules released as a result of replacement
of two chlorine atoms. Dibenzylamine hydrochloride
(IV) can be separated from crystalline compound III
by washing with water on a Schott filter.
A different pattern was observed in the reaction of
dibenzylamine with 4,6-dichloro-5,7-dinitrobenzofur-
azan (II). In this case, 4 equiv of the amine was also
necessary to ensure complete conversion of II. The
formation of bisammonium salt V via replacement of
both chlorine atoms was followed by debenzylation of
one dibenzylammonium group and deprotonation of
the other to afford compound VI (Scheme 2). These
processes require two dibenzylamine molecules.
Compound VI was isolated as a red crystalline sub-
stance. According to the spectral and X-ray diffraction
data, molecule VI contains one benzyamino group and
one dibenzylamino group on the six-membered
aromatic ring. In the IR spectrum of VI we observed
absorption bands typical of nitrobenzofurazans at 1624
(C=N), 1523 (NO2), and 980 cm–1, as well as a band at
3300 cm–1 due to N–H stretching vibration. Simulta-
neous TG/DSC analysis showed (Fig. 3) that com-
pound VI completely decomposes in the temperature
range from 144.1 to 182.9°C with a maximum at
175.3°C. The TG/DSC curves for compound VI are
much more complex than those found for III (Fig. 1).
The vigorous exothermic effect of sample decompo-
Scheme 2.
CH2Ph
H
PhCH2
PhCH2
O2N
CH2Ph
N
Cl
N
N
Cl–
··
HN(CH2Ph)2
O2N
Cl
O2N
N
N
N
N
4(PhCH2)2NH
O
O
O
–(PhCH2)3N·HCl
–(PhCH2)2NH·HCl
PhCH2
PhCH2
N
N
N
H
Cl–
PhCH2
H
NO2
NO2
NO2
··
HN(CH2Ph)2
II
V
VI
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

GALKINA et al.
594
Table 1. Some geometric parameters (bond lengths and bond angles) of molecules III and VI
Parameter
III
VI
Parameter
III
VI
Bond lengths d, Å
Bond angles ω, deg
O1–N1
N1–O2
N1–C7a
N3–O2
N3–C3a
C3a–C4
C3a–C7a
C4–C5
C4–N8
C5–C6
C5–N5
C6–C7
C6–N23
C7–C7a
C7–N7
1.202(5)
1.480(5)
1.309(6)
1.391(5)
1.371(6)
1.449(6)
1.397(6)
1.440(6)
1.312(5)
1.451(5)
1.424(5)
1.419(6)
1.338(5)
1.412(6)
1.437(6)
Bond angles ω, deg
108.9(4)
115.6(6)
137.0(7)
107.3(5)
102.7(5)
124.8(6)
114.0(6)
120.0(6)
123.1(5)
127.0(5)
–
C3aC4C5
C4C5C6
109.8(5)
120.3(5)
115.1(4)
121.5(5)
116.6(5)
120.4(5)
123.0(5)
116.4(5)
121.3(5)
116.8(5)
106.9(6)
131.1(6)
121.7(6)
123.9(5)
123.0(5)
113.1(4)
118.3(5)
118.3(5)
123.1(5)
123.3(4)
121.3(4)
115.3(4)
115.7(5)
124.1(5)
120.1(5)
110.9(3)
121.8(3)
116.7(3)
119.2(3)
117.6(3)
121.0(3)
121.4(3)
118.0(3)
122.7(3)
119.3(3)
109.3(3)
129.7(3)
121.0(3)
124.3(3)
124.0(3)
111.7(3)
119.3(3)
119.5(3)
120.8(3)
128.4(3)
113(2).0
118(2).0
120.7(3)
118.3(3)
121.0(3)
1.370(3
1.313(4)
1.394(3)
1.305(3)
1.468(4)
1.422(4)
1.430(4)
1.317(3)
1.453(4)
1.414(4)
1.415(4)
1.323(4)
1.424(4)
1.400(4)
C4C5N5
C6C5N5
C5C6C7
C5C6N24
C7C6N24
C6C7C7a
C6C7N7
C7aC7N7
N1C7aC3a
N1C7aC7
C3aC7aC7
C4N8C9
C4N8C17
C9N8C17
C5N5O51
C5N5O52
O51N5O52
C6N24C25
C6N24C32(H)
C25N24C32(H)
C7N7O71
C7N7O72
O71N7O72
N1O2N3
O1N1O2
O1N1C7a
O2N1C7a
O2N3C3a
N3C3aC4
N3C3aC7a
C7aC3aC4
C3aC4N8
C5C4N8
111.8(2)
–
–
104.3(3)
105.2(3)
129.3(3)
109.4(3)
121.3(3)
123.5(3)
125.6(3)
sition (6.9 mg) was preceded by a weak endothermic
effect with its maximum at 151.7°C. The decomposi-
tion process is likely to include evolution of small
amounts of gaseous products (N2, O2, H2O, NO, CO2).
The overall weight loss at 300°C was 43.76%. In ad-
dition, two weak exothermic effects were observed at
209 and 290.1°C; presumably, they reflect complex
thermal decomposition process involving profound
fragmentation of molecule VI.
The structure of compound VI was confirmed by
analytical and spectral data, including X-ray analysis
(Fig. 4). The structure of the benzofurazan fragment in
molecule VI in crystal is similar to the structure of the
benzofuroxan fragment in III. The benzene ring in VI
is distorted to a lesser extent as compared to III due to
weaker steric effect of less bulky substituent on C6.
The five-membered ring N1O2N3C3aC7a together with
the adjacent C4 and C7 atoms is planar within
0.053(3) Å, while the C5 and C6 atoms deviate from
that plane by 0.587(3) and 0.310(3) Å, respectively.
The benzene ring in VI is more planar than in III; the
C4 and C5 atoms deviate from the mean-square plane
by –0.173(3) and 0.187(3) Å, respectively, and the
nitrogen atoms in the substituents deviate from that
plane by 1.100(3) (N5), –0.345(3) (N7), –0.655(3) (N8),
and –0.265(3) Å (N23), i.e., to a considerably lesser
extent than in molecule III. However, as in III, the
deviations of the nitro groups are larger than those of
the amino groups. All nitrogen atoms in the substit-
uents have trigonal configuration, and their bond
planes almost coincide with the bond planes of the
corresponding carbon atoms in the benzene ring: the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

SYNTHESIS, STRUCTURE, AND ANTIBACTERIAL ACTIVITY
595
Ion current, A
DSC, mW/mg DTG, %/min
TG, %
100
Weight loss 2.47% Peak: 175.3°C
10
0–0
0–2
0–4
2
10–7
Peak: 146.2°C
95
90
85
80
Peak: 284.1°C
8
5
2
10–8
6
4
2
0
Weight loss 28.58%
Weight loss 3.99%
0–6
0–8
–10
–12
–14
5
Start: 166.8°C
2
10–9
75
70
65
60
Complex peak:
Area: 17.29 J/g
Peak: 208.7°C
Start: 194.7°C
End: 224.3°C
Weight loss 8.72%
5
2
10–10
Start: 144.1°C
Peak: 151.7°C
End: 182.9°C
End: 155.1°C
Peak: 290.1°C
250
5
Start: 259.8°C
Peak: 176.7°C
50
100
150
200
300
Temperature, °C
Fig. 3. Simultaneous TG/DSC curves for compound VI.
torsion angles are C9N8C4C3a –13.7(5), C24N24C6C5
11.8(6), C4C5N5O51 10.9(4), and C6C7N7O71 –0.3(5)°.
The principal geometric parameters of molecules III
and VI are collected in Table 1. Unlike compound III,
molecules VI in crystal are stabilized by the intra-
molecular hydrogen bond N23–H23 ···O71 [N23–H23
0.92(4), H23 ···O71 1.84(4), N23 ···O71 2.579(4) Å;
∠N23H23O71 137(3)°].
The observed difference in the reactivities of sub-
stituted benzofuroxans and benzofurazans I and II may
be related to higher electrophilicity of the former due
to the presence of a strong electron-withdrawing
N-oxide group. This favors increased rate of the
amination reaction leading to the disubstituted product.
The amination of less electrophilic benzofurazan II is
accompanied by subsequent debenzylation and depro-
tonation.
Newly synthesized bisamino benzofuroxan III and
benzofurazan VI showed pronounced antibacterial and
antifungal activity (Table 2) in tests on collection
strains of pathogenic and opportunistic human and
animal microorganisms (provided by the Microbiology
Department of the Kazan State Medical Academy):
Staphylococcus aureus (ATCC 29213), Escherichia
coli (ATCC 25922), Pseudomonas aeruginosa (ATCC
27853), Proteus mirabilis (ATCC 12453), and Candida
Albicans (ATCC 885-653). Compounds III and VI
were dissolved in DMSO immediately before use.
Bacterial culture was applied on Müller–Hinton agar
(MHA) in a Petri dish; after 5 min, a drop of a solution
of a compound to be tested was applied using an in-
oculating loop. A drop of DMSO as control was also
applied onto MHA in each dish. The cultures were
incubated for 24 h at 35°C. The results are given in
Table 2.
O72
N1
O2
N7
C7a
O71
C7
N3
C3a
N5
C6
C5
N23
C24
C25
C4
C30
C9
N8
C29
C28
O52
C22
C15
C14
C10
O51
C17
C16
C21
C20
C13
C11
C26
C27
C12
C19
C18
Fig. 4. Structure of the molecule of 6-benzylamino-4-di-
benzylamino-5,7-dinitro-2,1,3-benzoxadiazole (VI) accord-
ing to the X-ray diffraction data. The most populated posi-
tion of the disordered benzene ring C25–C30 is shown.
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GALKINA et al.
596
Table 2. Antimicrobial activity (growth inhibition zone, mm) of compounds III and VI and reference antimicrobial agents
(c = 50 μg/0.1 ml)
Staphylococcus
aureus
Pseudomonas
aeruginosa
Compound
III
Escherichia soli
Proteus mirabilis Candida albicans
25±0.2
20±0.3
16±0.5
023±0.35
0
20±0.1
22±0.3
15±0.2
016±0.15
0
011±0.15
13.5±0.3.0
13±0.5
08±0.1
0
11±0.4
013±0.15
14±0.3
10±0.2
0
24±0.1
23±0.1
16.5±0.2.0
–
VI
Chlorhexidine
Penicillin
Griseofulvin
19±0.2
EXPERIMENTAL
in 5 ml of ethanol–diethyl ether (1:3) was added drop-
wise under stirring to a solution of 0.56 g (3 mmol) of
dibenzylamine in 5 ml of the same solvent. The
originally yellow mixture turned red, and bright red
fine crystals separated over a period of 24 h. After
4 months, a druse of single crystals suitable for X-ray
analysis was obtained. The product was filtered off on
a Schott filter and washed with ethanol and diethyl
ether to remove unreacted initial compounds. Yield
0.27 g (65%), mp 153.4°C (decomp.). IR spectrum, ν,
cm–1: 3300 (N–H), 1620 (C=N), 1523 (NO2), 1492
(C–N), 980 (N–O). Found, %: C 63.56; H 3.45;
N 16.14. C27H22N6O5. Calculated, %: C 63.91; H 3.75;
N 16.57.
X-Ray analysis of single crystals of III and VI was
carried out on a Bruker SMART Apex II diffractometer
(graphite monochromator, λMoKα 0.71073 Å). No
correction for absorption was applied because of its
insignificance. The structures were solved by the direct
method and were refined first in isotropic and then in
anisotropic approximation using SHELX software
[22]. Hydrogen atoms were placed into calculated
positions. All calculations were performed with the aid
of WinGX [23] and APEX2 [24], and the molecular
structures were plotted using PLATON [25]. The X-ray
diffraction data for compounds III and VI were de-
posited to the Cambridge Crystallographic Data centre
(entry nos. CCDC 925345 and 925346, respectively).
The IR spectra (400–3700 cm–1) were recorded on
a Specord M-80 spectrometer from samples dispersed
in mineral oil and placed between KBr plates. The
purity and thermal stability of compounds III and VI
were determined by simultaneous TG/DSC analysis on
a NETZSCH STA 449C instrument (temperature range
20–400°C, heating rate 10 deg/min, argon atmo-
sphere).
After mixing of compounds I and II with dibenzyl-
amine at different ratios in ethanol–diethyl ether (1:3)
at room temperature under vigorous stirring, the mix-
ture rapidly turned colored. The mixture was kept for
two weeks to complete the reaction, the products were
purified, and special operations were carried out to
obtain single crystals. The solvents were purified
according to standard procedures [21]. All initial reac-
tants were distilled just before use, and their purity was
checked by comparing their physical constants with
published data.
4,6-Bis(dibenzylamino)-5,7-dinitro-2,1,3-benz-
oxadiazole 1-oxide (III). A solution of 0.5 g
(1.7 mmol) of 4,6-dichloro-5,7-dinitrobenzofuroxan in
10 ml of ethanol–diethyl ether (1:3) was added drop-
wise under stirring to a solution of 1.34 g (6.8 mmol)
of dibenzylamine in 10 ml of the same solvent. The
originally colorless mixture turned bright red, and dark
red fine crystals separated over a period of 24 h. The
crystals were filtered off on a Schott filter and washed
with ethanol and diethyl ether to remove unreacted
initial compounds. Yield 0.83 g (67%), mp 178.5°C
(decomp.). IR spectrum, ν, cm–1: 1624 (C=N), 1523
(NO2), 1492 (C–N), 980 (N–O). Found, %: C 65.92;
H 4.28; N 13.55. C34H28N6O6. Calculated, %: C 66.21;
H 4.52; N 13.64.
Compound III. Triclinic crystals, C34H28N6O6; unit
cell parameters (20°C): a = 9.548(5), b = 12.465(7),
c = 13.608(7) Å; α = 79.515(7), β = 71.609(6), γ =
79.489(7)°; V = 1497.5(1) Å3; Z = 2; dcalc = 1.367 g×
cm–3; space group P-1; μMo = 0.93 cm–1. Intensities of
5777 independent reflections were measured, 1628 of
which were characterized by I ≥ 2σ. Final divergence
factors R = 0.0753, Rw = 0.0999.
6-Benzylamino-4-dibenzylamino-5,7-dinitro-
2,1,3-benzoxadiazole (VI). A solution of 0.2 g
(0.75 mmol) of 4,6-dichloro-5,7-dinitrobenzofurazan
Compound VI. Triclinic crystals, C27H22N6O5; unit
cell parameters (20°C): a = 7.591(1), b = 13.463(2),
c = 13.795(4) Å; α = 114.525(3), β = 99.512(3), γ =
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

SYNTHESIS, STRUCTURE, AND ANTIBACTERIAL ACTIVITY
597
100.451(2)°; V = 1214.9(4) Å3; Z = 2; dcalc = 1.396 g×
cm–3; space group P-1; μMo = 0.99 cm–1. Intensities of
4694 independent reflections were measured; 2114 re-
flections with I ≥ 2σ. Final divergence factors R =
0.0622, Rw = 0.1253. The NH hydrogen atom was
localized by the Fourier difference series, and its
position was refined in isotropic approximation. The
phenyl group in the benzylamino substituent is dis-
ordered by two positions with populations of 0.52 and
0.48 due to rotation about the C24–C25 bond.
12. Galkina, I.V., Tudriy, E.V., Kataeva, O.N., Usupo-
va, L.M., Luftmann, H., and Galkin, V.I., Phosphorus,
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13. Galkina, I.V., Tudrii, E.V., Yusupova, L.M., Katae-
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Kazan. Univ., Ser. Estestv. Nauki, 2008, vol. 150,
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va, L.M., Levinson, F.S., Sakhibullina, V.G., Gnezdi-
lov, O.I., Il’yasov, A.V., Kataeva, O.N., Krivola-
pov, D.B., and Galkin, V.I., Uch. Zap. Kazan. Univ., Ser.
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Patent no. 2465279; Byull. Izobret., 2012, no. 30.
17. Galkina, I.V., Egorova, S.N., Yusupova, L.M.,
Tudrii, E.V., Bakhtiyarova, Yu.V., Vorob’eva, N.V.,
Lutfullina, N.A., Idrisov, A.M., Gizzatullin, R.R., Kiri-
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