Thermolysis of 1-(methylideneamino)-1H-pyrrole-2,3-diones. Formation of pyrazolodioxazines at [4+2]-cycloaddition of azomethinimines to arylcarbaldehydes

Article abstract of DOI:10.1134/S107042801705013X

4-Acyl-1-[(diphenylmethylidene)amino]-5-methoxycarbonyl-1Н-pyrrole-2,3-diones generate at the thermolysis 4-acyl-3-(methoxycarbonyl)-1-(diphenylmethylidene)-1H-pyrazol-1-ium-5-olates that react with aromatic aldehydes to form methyl 2-aryl-8-acyl-4,4-diph

Full text of DOI:10.1134/S107042801705013X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2017, Vol. 53, No. 5, pp. 729–733. © Pleiades Publishing, Ltd., 2017.
Original Russian Text © V.E. Zhulanov, M.V. Dmitriev, A.N. Maslivets, 2017, published in Zhurnal Organicheskoi Khimii, 2017, Vol. 53, No. 5, pp. 719–722.
Thermolysis of 1-(Methylideneamino)-1H-pyrrole-2,3-diones.
Formation of Pyrazolodioxazines at [4+2]-Cycloaddition
of Azomethinimines to Arylcarbaldehydes
V. E. Zhulanov, M. V. Dmitriev, and A. N. Maslivets*
Perm State National Reserch University, ul. Bukireva 15, Perm, 614990 Russia
*e-mail: koh2@psu.ru
Received March 1, 2017
Abstract—4-Acyl-1-[(diphenylmethylidene)amino]-5-methoxycarbonyl-1Н-pyrrole-2,3-diones generate at the
thermolysis 4-acyl-3-(methoxycarbonyl)-1-(diphenylmethylidene)-1H-pyrazol-1-ium-5-olates that react with
aromatic aldehydes to form methyl 2-aryl-8-acyl-4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]dioxazine-7-
carboxylates whose structure is proved by X-ray diffraction analysis.
DOI: 10.1134/S107042801705013X
Structural fragments of oxazines and dioxazines are
present in a number of synthetic [1–7] and natural [8–
10] biologically active compounds exhibiting a
tuberculocidal [1, 2], anticonvulsant [3], antimicrobial
[4], and other kinds of activity.
mobenzaldehyde [11]. In order to explore the
limitations of the applicability of this reaction we used
as dipolarophiles in this study aromatic aldehydes both
with electron-donor and electron-acceptor substituents.
The reaction of enhydrazines 1a–1d with oxalyl
chloride in anhydrous chloroform at 60–65°С within
90–100 min leads to the formation of 4-acyl-1-
[(diphenylmethylidene)amino]-5-methoxycarbonyl-1Н-
pyrrole-2,3-diones 2a–2d used in further processes
without isolation.
We formerly developed a convenient method of
synthesis of pyrazolo[5,1-d][1,3,5]dioxazines based on
the reaction of dipolar [4+2]-cycloaddition of 1,4-
dipoles generated in situ from 1-(diphenylmethylidene)
amino-substituted 1Н-pyrrole-2,3-diones with 4-bro-
R1OC
O
R1OC
R1
O
O
Ph
(COCl)2
H
O
MeOOC
MeOOC
N
N
N
N
N
N
Ph
Ph
Ph
COOMe
Ph
Ph
2a_2d
1a_1d
5
R1OC
R1OC
R1OC
_
O
O
R2CHO
3a_3c
R2
O
MeOOC
MeOOC
MeOOC
N
Ph
N
Ph
N
O
+
+
N
N
N
_
Ph
Ph
4a_4i
Ph
Ph
7
6
1, 2, R1 = Ph (a), C6H4Me-4 (b), C6H4Cl-4 (c), t-Bu (d); 3, R2 = C6H4Br-4 (a), C6H3Cl2-2,4 (b), Ph (c); 4, R2 = C6H4Br-4,
R1 = Ph (a), C6H4Me-4 (b), C6H4Cl-4 (c); R2 = C6H4Cl2-2,4, R1 = Ph (d), C6H4Me-4 (e), C6H4Cl-4 (f), t-Bu (g);
R1 = R2 = Ph (h); R1 = C6H4Me-4, R2 = Ph (i).
729

ZHULANOV et al.
730
C1
O1
C1
C2
C6
C5
O3
C3
Br1
C3
C16
C4
C17
C2
O1
C20
C15
C13
O4
C12
N1
C22
C6
C18
C14
C18
C19
O3
C7
C8
C17
C21
C9
C27
C9
O5
C4
C14
N2
C10
C11
C5
C7
C10
C29
C15
O5
O2
C22
O2
C13
C12
C8
C11
N1
N2
C27
C23
C32
C23
C30
C16
C24
C25
C20
O4
C28
C29
C21
C28
C24
C19
C26
C26
C25
C32
C31
C31
Cl2
C30
Cl1
Fig. 1. Molecular structure of methyl 8-benzoyl-2-(4-
bromophenyl)-4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]-
dioxazine-7-carboxylate 4a. Nonhydrogen atoms are
represented by thermal ellipsoids of 50% probability.
Fig. 2. Molecular structure of methyl 8-benzoyl-2-(2,4-
dichlorophenyl)-4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]-
dioxazine-7-carboxylate 4d. Nonhydrogen atoms are
represented by thermal ellipsoids of 50% probability.
Boiling of a solution of 1Н-pyrrole-2,3-diones 2a–
2d, obtained in situ, with aromatic aldehydes 3a–3с in
a 1 : 1 ratio in anhydrous o-xylene at 130–140°С
within 30–40 min afforded in good yields methyl 2-
aryl-8-acyl-4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]-
dioxazine-7-carboxylates 4a–4i whose structure was
proved by X-ray diffraction (XRD) analysis of
compounds 4a and 4d.
pyrazole ring and the planar fragments
C21C22С23C24C25С26 and C27C28С29C30C31С32 are 76.6
and 82.4 deg respectively. The multiple bonds in the
pyrazole ring are essentially delocalized, the length
difference of the formally ordinary bonds С9–N2
[1.350(3) Å], С8–C10 [1.413(4) Å] and formally double
bonds С10=N1 [1.324(4) Å], С9=С8 [1.386(4) Å] does
not exceed 0.03 Å. The molecules in the crystal are
bound with non-classical intermolecular hydrogen
bonds С24–H24···O4 [C24···H24 0.931, H24···O4 2.340,
C24···O4 3.253(4) Å] and С6–H6···O1 [C6···H6 0.929,
H6···O1 2.504, C6···O1 3.414(8) Å].
Compounds 4a–4i are colorless crystalline
substances readily soluble in DMSO, chloroform, and
acetone, insoluble in alkanes and water.
1Н NMR spectra of compounds 4a–4i along with
the signals of the protons of aromatic rings and the
groups attached to them, of proton signals from a tert-
butyl group (4d and 4g) contain the singlets of the
three protons of the methoxycarbonyl group (3.52–
3.75 ppm) and of the methine proton (6.21–6.56 ppm).
According to XRD data compound 4d (Fig. 2)
crystallized in a centrosymmetric space group of the
triclinic crystal system. The molecular geometry of
compound 4d is close to the geometry of compound
4а. The pyrazole ring is planar within 0.01 Å. The
dioxazine ring is present in the conformation
intermediate between sofa and semichair. The О2 atom
deviates from the plain of the other five atoms by
0.34 Å. In the crystal of compound 4d several
shortened contacts CH···O are present, but these
interactions play considerably lesser role in the
stabilization of the crystal packing than analogous
interactions in the crystal of compound 4а.
According to XRD data compound 4a (Fig. 1)
crystallized in a centrosymmetric space group of the
monoclinic crystal system. The pyrazole ring is flat
within 0.01 Å. Dioxazine ring is present in the
semichair conformation, С13 and О2 atoms deviate
from the plain of the other atoms by 0.32 and –0.36 Å
respectively. The angles between the plain of the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017

THERMOLYSIS OF 1-(METHYLIDENEAMINO)-1H-PYRROLE-2,3-DIONES
731
1
The formation of compounds 4a–4i occurs
apparently due to the thermal decarbonylation of
cm–1: 1734, 1638, 1603, 1553. Н NMR spectrum
(CDCl3), δ, ppm: 3.57 s (3H, COOMe), 6.21 s (1H,
C2H), 7.31–7.57 m (17Harom), 7.83–7.87 d.t (2Harom, J
8.5, 1.6 Hz). 13C NMR spectrum (CDCl3), δ, ppm: 52.3
(MeОСО), 95.6, 96.6, 104.3, 124.7, 127.3 (2C), 128.1
(2C), 128.4 (2C), 128.4 (2C), 128.6 (2C), 129.1 (2C),
129.3 (2C), 130.0, 130.2, 132.0 (2C), 132.8, 132.9,
138.6, 138.7, 139.0, 142.8, 150.6, 162.3 (MeОСО),
187.9 (ArCO). Found, %: C 64.61; H 3.78; N 4.67.
С32H23BrN2О5. Calculated, %: C 64.55; H 3.89; N
4.70.
pyrrolediones
2
leading to the generation of
hydrazonoylketenes 5 undergoing an intramolecular
cyclization with the formation of azomethinimines 6
capable in the absence of capturing agent to dimerize
along [3+3] or [4+4] type [11]. In the presence of
aromatic aldehydes azomethinimines 6 in the enolate-
iminium form 7 enter in the reaction of dipolar [4+2]-
cycloaddition with aromatic aldehydes. The use of
arylcarbaldehydes with electron-donor substituents like
anisic and veratric aldehydes resulted in a sharp
decrease in the reaction regioselectivity: the formation
in a low yield of pyrazolo[5,1-d][1,3,5]dioxazines 4
was confirmed by HPLC-MS method, but individual
reaction products were not isolated.
Compounds 4b–4i were similarly prepared.
Methyl 2-(4-bromophenyl)-8-(4-methylbenzoyl)-
4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]dioxazine-7-
carboxylate (4b). Yield 66%, mp 187–190°С
(acetone, decomp.). IR spectrum, ν, cm–1: 1734, 1638,
The described reaction is an example of the
synthesis of difficultly available substituted pyrazolo-
[5,1-d][1,3,5]dioxazines with several functional
substituents in the pyrazole and dioxazine rings.
1
1603, 1553. Н NMR spectrum (CDCl3), δ, ppm: 2.41
s (3H, Me), 3.60 s (3H, MeОСО), 6.20 s (1H, C2H),
7.23 d (2Harom, J 7.9 Hz), 7.31–7.50 m (12Harom), 7.52
d (2Harom, J 8.4 Hz), 7.76 d (2Harom, J 8.1 Hz). 13C
NMR spectrum (CDCl3), δ, ppm: 21.8 (Me), 52.2
(MeОСО), 95.6, 96.6, 104.5, 124.7, 127.4 (2C), 128.2
(2C), 128.3 (2C), 128.6 (2C), 129.1 (2C), 129.1 (2C),
129.5 (2C), 130.0, 130.2, 132.0 (2C), 133.0, 136.2,
138.8, 138.7, 139.2, 142.7, 143.8, 150.3, 162.3
(MeОСО), 187.6 (ArCO). Found, %: C 64.77; H 4.29;
N 4.56. C33H25BrN2O5. Calculated, %: C 65.03; H
4.13; N 4.60.
EXPERIMENTAL
IR spectra were recorded on a spectrophotometer
Perkin Elmer Spectrum Two from mulls in mineral oil.
1Н and 13C NMR spectra were registered on spec-
trometers Bruker DRX 400 or Bruker Avance III HD
400 [operating frequencies 400 (1Н) and 100 (13C) МHz],
internal reference HMDS. Elemental analysis was carried
out on an analyzer vario Micro cube. For optimization
of reaction conditions method HPLC-MS was used:
column Acquity UPLC BEH C18 1.7 µm, mobile
phases acetonitrile–water, flow rate 0.6 mL/min,
detector ESI MS Xevo TQD. The homogeneity of
compounds synthesized was confirmed by TLC on
Silufol plates, eluents benzene–ethyl acetate, 5 : 1,
ethyl acetate, development in iodine vapor.
Methyl 2-(4-bromophenyl)-4,4-diphenyl-8-(4-
chlorobenzoyl)-4H-pyrazolo[5,1-d][1,3,5]dioxazine-
7-carboxylate (4c). Yield 69%, mp 170–172°С
(acetone, decomp.). IR spectrum, ν, cm–1: 1733, 1641,
1
1588, 1552. Н NMR spectrum (CDCl3), δ, ppm: 3.63
s (3H, MeОСО), 6.21 s (1H, C2H), 7.31–7.57 m
(16Harom), 7.79 d (2Harom, J 8.4 Hz). 13C NMR
spectrum (CDCl3), δ, ppm: 52.3 (MeОСО), 95.8, 96.7,
104.1, 124.9, 127.3 (2C), 128.1 (2C), 128.4 (2C),
128.6 (2C), 128.8 (2C), 129.2 (2C), 130.1, 130.2,
130.7 (2C), 132.1 (2C), 132.7, 137.1, 138.6, 139.0,
139.4, 142.7, 150.6, 162.2 (MeОСО), 190.4 (ArCO).
Found, %: C 60.81; H 3.53; N 4.43. C32H22ClBrN2O5.
Calculated, %: C 61.02; H 3.52; N 4.45.
Methyl 8-benzoyl-2-(4-bromophenyl)-4,4-diphe-
nyl-4H-pyrazolo[5,1-d][1,3,5]dioxazine-7-carbo-
xylate (4a). To a solution of 1.0 mmol of compound
1a in 5 mL of anhydrous chloroform was added
1.0 mmol of oxalyl chloride, the mixture was boiled
for 90 min, then 5 mL of anhydrous о-xylene was
added, and chloroform was distilled off. The solution
was stirred at 130–140°С (while boiling) for 10 min,
then 1.0 mmol of p-bromobenzaldehyde was added,
and the boiling was continued for 15 min more. The
solution was cooled, evaporated in a vacuum, the
formed precipitate was recrystallized from acetone.
Yield 68%, mp 167–170°С (decomp.). IR spectrum, ν,
Methyl 8-benzoyl-2-(2,4-dichlorophenyl)-4,4-
diphenyl-4H-pyrazolo[5,1-d][1,3,5]dioxazine-7-car-
boxylate (4d). Yield 60%, mp 172–174°С (acetone,
decomp.). IR spectrum, ν, cm–1: 1733, 1646, 1596,
1
1588. Н NMR spectrum (DMSO-d6), δ, ppm: 3.57 s
(3H, MeОСО), 6.56 s (1H, C2H), 7.33–7.66 m
(14Harom), 7.73 d (1Harom, J 2.0 Hz), 7.88 d (2Harom, J
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017

ZHULANOV et al.
732
7.3 Hz), 7.92 d (1Harom, J 8.4 Hz). Found, %: C 65.55;
H 3.75; N 4.75. C32H22Cl2N2O5. Calculated, %: C
65.65; H 3.79; N 4.79.
128.4 (2C), 128.6 (2C), 128.7 (2С), 129.1 (2С), 129.3
(2C), 129.9, 130.0, 130.4, 132.8, 133.9, 138.8, 138.9,
139.3, 142.9, 150.8, 162.4 (MeОСО), 187.9 (ArCO).
Found, %: C 74.36; H 4.55; N 5.40. C32H24N2O5.
Calculated, %: C 74.41; H 4.68; N 5.42.
Methyl 2-(2,4-dichlorophenyl)-8-(4-methyl-
benzoyl)-4,4-diphenyl-4H-pyrazolo[5,1-d][1,3,5]-
dioxazine-7-carboxylate (4e). Yield 63%, mp 203–
206°С (acetone, decomp.). IR spectrum, ν, cm–1: 1732,
Methyl 8-(4-methylbenzoyl)-2,4,4-triphenyl-4H-
pyrazolo[5,1-d][1,3,5]dioxazine-7-carboxylate (4i).
Yield 38%, mp 173–176°С (acetone, decomp.). IR
1
1642, 1604, 1556. Н NMR spectrum (DMSO-d6), δ,
1
ppm: 2.37 s (3Н, Me), 3.57 s (3Н, MeОСО), 6.55 s
(1Н, C2H), 7.31–7.46 m (8Нarom), 7.56–7.63 m
(4Нarom), 7.71–7.75 m (2Нarom), 7.77 d (2Harom, J
8.1 Hz), 7.91 d (1Нarom, J 8.5 Hz). Found, %: C 66.05;
H 4.02; N 4.64. C33H24Cl2N2O5. Calculated, %: C
66.12; H 4.04; N 4.67.
spectrum, ν, cm–1: 1739, 1636, 1605, 1557. Н NMR
spectrum (CDCl3), δ, ppm: 2.41 s (3Н, Me), 3.61 s
(3H, MeOCO), 6.26 s (1Н, C2H), 7.24 d (2Нarom, J
7.9 Hz), 7.35–7.55 m (15Нarom), 7.78 d (2Harom, J
8.1 Hz). 13C NMR spectrum (CDCl3), δ, ppm: 21.8
(Me), 52.2 (MeОСО), 96.3, 96.5, 104.5, 126.5 (2C),
127.4 (2C), 128.3 (2C), 128.6 (2C), 128.7 (2C), 129.0
(2С), 129.1 (2С), 129.5 (2C), 129.9, 130.0, 130.3,
133.9, 136.2, 138.9, 139.3, 142.7, 143.7, 150.6, 162.4
(MeОСО), 187.7 (ArCO). Found, %: C 74.54; H 4.81;
N 5.25. C33H26N2O5. Calculated, %: C 74.70; H 4.94;
N 5.28.
Methyl 2-(2,4-dichlorophenyl)-4,4-diphenyl-8-(4-
chlorobenzoyl)-4H-pyrazolo[5,1-d][1,3,5]dioxazine-
7-carboxylate (4f). Yield 60%, mp 175–177°С
(acetone, decomp.). IR spectrum, ν, cm–1: 1732, 1644,
1
1588, 1556. Н NMR spectrum (DMSO-d6), δ, ppm:
3.60 s (3Н, MeОСО), 6.58 s (1Н, C2H), 7.35–7.48 m
(7Нarom), 7.55–7.62 m (5Нarom), 7.65 d.d (1Нarom, J 8.4,
1.9 Hz), 7.73 d (1Harom, J 2.0 Hz), 7.90 d (2Нarom, J
8.6 Hz), 7.94 d (1Нarom, J 8.5 Hz). Found, %: C 61.94;
H 3.39; N 4.50. C32H21Cl3N2O5. Calculated, %: C
62.00; H 3.41; N 4.52.
X-ray diffraction analysis of compounds 4a and
4d was carried out on an automatic four-circle
diffractometer Xcalibur R (Agilent Technologies) by a
standard procedure [MoKα-radiation, 295(2) K, ω-
scanning, scan step 1°] applying program package
CrysAlisPro [12]. The extinction was accounted for
empirically using the algorithm SCALE3 ABSPACK
[12]. The structures were solved by the direct method
using the program SHELXS-97 and refined applying
the program SHELXL-97 [13] with respect to F2 in an
anisotropic approximation for nonhydrogen atoms
(hydrogen atoms were included in the refinement in
the rider model in an isotropic approximation with
dependent thermal parameters).
Methyl 8-(2,2-dimethylpropanoyl)-2-(2,4-di-
chlorophenyl)-4,4-diphenyl-4H-pyrazolo[5,1-d]-
[1,3,5]dioxazine-7-carboxylate (4g). Yield 62%, mp
156–158°С (acetone, decomp.). IR spectrum, ν, cm–1:
1
1730, 1640, 1600, 1556. Н NMR spectrum (DMSO-
d6), δ, ppm: 1.16 s (9Н, Me3С), 3.75 s (3H, MeOCO),
6.57 s (1Н, C2H), 7.26–7.49 m (7Нarom), 7.54–7.62 m
(3Нarom), 7.67 d.d (1Нarom, J 8.5, 1.9 Hz), 7.78 d
(1Harom, J 1.9 Hz), 7.96 d (1Нarom, J 8.5 Hz). 13C NMR
spectrum (DMSO-d6), δ, ppm: 25.8 (3C, Me, Me3С),
43.9 (Me3С), 52.2 (MeОСО), 93.4, 96.0, 104.0, 127.0
(2C), 128.0 (2C), 128.3 (3C), 128.9 (2C), 129.7, 129.8,
130.0, 130.2 (2C), 133.1, 136.5, 137.7, 138.4, 141.6,
146.2, 162.0 (MeОСО), 201.9 (Me3CCO). Found, %:
C 63.63; H 4.61; N 4.92. C30H26Cl2N2O5. Calculated,
%: C 63.72; H 4.63; N 4.95.
For analysis of compound 4a was used a fragment
of a colorless crystal of the size 0.4 × 0.3 × 0.25 mm.
Crystal system monoclinic, a 11.941(3), b 18.538(3), c
12.5422(17) Å, β 91.318(17)°, space group P21/c, Z 4.
The completeness of data collection for θ<26.00°
99.9%. Final refinement parameters are as follows: R1
0.0617, wR2 0.1737 [for 3861 reflections with I>2σ(I)],
R1 0.1113, wR2 0.2028 (for all 6761 independent
reflections, Rint 0.0386), GOOF 1.112, Δρ 0.726/–
1.186 ēÅ–3.
Methyl 8-benzoyl-2,4,4-triphenyl-4H-pyrazolo-
[5,1-d][1,3,5]dioxazine-7-carboxylate (4h). Yield
63%, mp 160–162°С (acetone, decomp.). IR spectrum,
1
ν, cm–1: 1731, 1649, 1597, 1572. Н NMR spectrum
For analysis of compound 4d was used a colorless
crystal of the size 0.1 × 0.1 × 0.07 mm. Crystal system
triclinic, a 7.0550(11), b 10.5792(17), c 19.621(3) Å,
α 86.223(13), β 88.169(12), γ 73.157(14)°, space
group Р–1, Z 2. The completeness of data collection
(CDCl3), δ, ppm: 3.59 s (3H, MeOCO), 6.27 s (1Н,
C2H), 7.35–7.56 m (18Нarom), 7.85–7.89 m (2Нarom).
13C NMR spectrum (CDCl3), δ, ppm: 52.2 (MeОСО),
96.3, 96.5, 104.3, 126.4 (2C), 127.4 (2C), 128.3 (2C),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017

THERMOLYSIS OF 1-(METHYLIDENEAMINO)-1H-PYRROLE-2,3-DIONES
733
4. Haneishi, T., Okazaki, T., Hata, T., Tamura, C.,
Nomura, M., Naito, A., Seki, I., and Arai, M.,
J. Antibiot., 1971, vol. 24, p. 797. doi 10.7164/
antibiotics.24.797
for θ < 26.00°, 99.9%. Final refinement parameters are
as follows: R1 0.0611, wR2 0.1229 [for 2879 reflections
with I > 2σ(I)], R1 0.1618, wR2 0.1697 (for all 6604
independent reflections, Rint 0.0570), GOOF 0.964, Δρ
0.317/–0.315 ē Å–3.
5. Townes, J.A., Golebiowski, A., Clark, M.P.,
Laufersweiler, M.J., Brugel, T.A., Sabat, M.,
Bookland, R.G., Laughlin, S.K., Van-Rens, J.C.,
Biswanath, D., Hsieh, L.C., Xu, S.C., Janusz, M.J., and
Walter, R.L., Bioorg. Med. Chem. Lett., 2004, vol. 14,
p. 4945. doi 10.1016/j.bmcl.2004.07.024
The results of structural experiments are deposited
to Cambridge Crystallographic Data Centre under the
numbers CCDC 1457142 (4a) and CCDC 1531814
(4d). These data are available free at the address
www.ccdc.cam.ac.uk.
6. Patel, M.V., Bell, R., Majest, S., Henry, R., and
Kolasa, T., J. Org. Chem., 2004, vol. 69, p. 7058. doi
10.1021/jo049264k
ACKNOWLEDGMENTS
The study was carried out under a financial support
of the Ministry of Education and Science of the
Russian Federation, of the Council of grants of the
President of the Russian Federation (grant no. MK-
1657.2017.3) and of the Russian Foundation for Basic
Research (grant no.16-43-590613).
7. Zhang, W. and Mccann, S.F., WO Patent
no. 2010005692, 2010.
8. Atta-ur-Rahman, Fatima T., and Khanum S.,
Tetrahedron, 1989, vol. 45, p. 3507. doi 10.1016/
S0040-4020(01)81029-2
9. Atta-ur-Rahman, Pure Appl. Chem., 1989, vol. 61,
p. 453. doi 10.1351/pac198961030453
REFERENCES
10. Uzir, S., Mustapha, A.M., Hadi, A.H.A.,
Awang, K., Wiart, C., Gallard, J.-F., and Paїs, M.,
Tetrahedron Lett., 1997, vol. 38, p. 1571. doi 10.1016/
S0040-4039(97)00152-4
1. Singh, R., Manjunatha, U., Boshoff, H.I.M., Ha, Y.H.,
Niyomrattanakit, P., Ledwidge, R., Dowd, C.S., Lee, I.Y.,
Kim, P., Zhang, L., Kang, S., Keller, T.H., Jiricek, J.,
and Barry, C.E., Science, 2008, vol. 322, p. 1392. doi
10.1126/science.1164571
2. Thompson, A.M., Blaser, A., Anderson, R.F., Shinde, S.S.,
Franzblau, S.G., Ma, Z., Denny, W.A., and Palmer, B.D.,
J. Med. Chem., 2009, vol. 52, p. 637. doi 10.1021/
jm801087e
11. Zhulanov, V.E., Dmitriev, M.V., Maslivets, A.N., and
Rubin, M., RSC Adv., 2016, vol. 6, p. 90239. doi
10.1039/C6RA21981K
12. CrysAlisPro, Agilent Technologies, Version
1.171.36.28 (release 01-02-2013 CrysAlis171 .NET).
13. Sheldrick, G.M., Acta Cryst. Sect. A, 2008, vol. 64,
3. Kuch, H., Schmitt, K., Seidl, G., and Hoffmann, I., US
Patent no. 3725404, 1973.
p. 112. doi 10.1107/S0108767307043930
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 53 No. 5 2017