Five-membered 2,3-dioxo heterocycles: L. Synthesis and thermolysis of 3-aroyl- and 3-hetaroyl-5-phenyl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxalin-1,2, 4-triones

Article abstract of DOI:10.1007/s11178-005-0296-6

(Z)-3-Phenacylidene- and (Z)-3-hetaroylmethylidene-1-phenyl-1,2,3,4- tetrahydroquinoxalin-2-ones react with oxalyl chloride to give 3-acyl-5-phenyl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxaline-1,2,4-triones. Thermolysis of the latter generates acyl(3-oxo-4

Full text of DOI:10.1007/s11178-005-0296-6

Russian Journal of Organic Chemistry, Vol. 41, No. 7, 2005, pp. 1081–1088. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005,
pp. 1101–1108.
Original Russian Text Copyright © 2005 by Bozdyreva, Smirnova, Maslivets.
Five-Membered 2,3-Dioxo Heterocycles: L.* Synthesis
and Thermolysis of 3-Aroyl- and 3-Hetaroyl-5-phenyl-1,2,4,5-
tetrahydropyrrolo[1,2-a]quinoxalin-1,2,4-triones
K. S. Bozdyreva, I. V. Smirnova, and A. N. Maslivets
Perm State University, ul. Bukireva 15, Perm, 614990 Russia
e-mail: koh2@psu.ru
Received September 21, 2004
Abstract—(Z)-3-Phenacylidene- and (Z)-3-hetaroylmethylidene-1-phenyl-1,2,3,4-tetrahydroquinoxalin-2-ones
react with oxalyl chloride to give 3-acyl-5-phenyl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxaline-1,2,4-triones.
Thermolysis of the latter generates acyl(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)ketenes which are
stabilized via [4+2]-cyclodimerization followed by [1,3]-acylotropic shift to afford 4-acyl-3-acyloxy-2-(3-oxo-
4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-1,5-diones.
Thermal decarbonylation of five-membered dioxo
heterocycles [2–18] underlies a convenient method for
generation of functionally substituted heterocumu-
lenes, including acyl(imidoyl)ketenes. In continuation
of our studies in the field of generation and stabiliza-
tion of acyl(imidoyl)ketenes in which the imidoyl frag-
ment is a part of a heterocyclic system, we examined
methods of synthesis and thermal transformations of
compounds belonging to a new class of five-membered
dioxo heterocycles.
For example, the reaction of (Z)-3-ethoxycarbonyl-
methylidene-1,2,3,4-tetrahydroquinoxalin-2-one with
oxalyl chloride leads to formation of expected
3-ethoxycarbonyl-1,2,4,5-tetrahydropyrrolo[1,2-a]-
quinoxaline-1,2,4-trione and 4-ethoxycarbonyl-3,5-di-
hydro-2H-pyrano[2,3-b]quinoxaline-2,3-dione as
minor product [8].
As shown in recent publications [7, 9, 10], another
pathway is possible in the reaction of heterocyclic
enaminoketones with oxalyl chloride. (Z)-3-Aryl-2-
phenacylidene-1,2-dihydroquinoxalines react with
oxalyl chloride to afford compounds belonging to
a new class of 4-heteryl-2,3-dihydrofuran-2,3-diones,
3-aryl-2-(2-aryl-4,5-dioxo-4,5-dihydro-3-furyl)quino-
xalines [7], instead of the expected 3-aroyl-4-aryl-1,2-
dihydropyrrolo[1,2-a]quinoxaline-1,2-diones [7]. Like-
wise, 2-(4,5-dioxo-2-phenyl-4,5-dihydro-3-furyl)-4H-
3,1-benzoxazin-4-one was obtained from (E)-2-phen-
acylidene-2,4-dihydro-1H-3,1-benzoxazin-4-one and
oxalyl chloride [9], while 2,3-bis(phenacylidene)-
1,2,3,4-tetrahydroquinoxaline gave rise to 2,3-bis(2-
phenyl-4,5-dioxo-4,5-dihydro-3-furyl)quinoxaline
(bis-furandione) [7, 10]. The predominant pathway in
the reaction with oxalyl chloride is likely to be deter-
mined by the structure of enaminoketone, and study of
the effect of this factor is an important aspect of the
present work.
Reactions of heterocyclic enaminoketones with
oxalyl chloride are widely used for the preparation of
4-acyl-2,3-dihydropyrrole-2,3-diones fused through
the [a] side with nitrogen-containing heterocycles
[2–7]. Such reactions with substituted 1-acylmethyli-
dene-1,2,3,4-tetrahydroisoquinolines [3], 3-acylmeth-
ylidene-3,4-dihydro-2H-1,4-benzoxazin-2-ones [4],
2-acylmethylidene-3,4-dihydro-2H-1,3-benzoxazin-4-
ones [5], 2-phenacylidene-1,2,3,5-tetrahydro-4,1-benz-
oxazepin-3-ones [6], and 2-phenacylidene-3-phenyl-
1,2,3,4-tetrahydroquinazolin-4-ones [7] produce the
corresponding 4-acyl-2,3-dihydropyrrole-2,3-diones
fused through the [a] side to isoquinoline, 1,4- and 1,3-
benzoxazine, 4,1-benzoxazepine, and quinazoline rings
in almost quantitative yield. These reactions are gen-
erally smooth; however, if the initial enaminoketone
possesses an additional center capable of being acylat-
ed with oxalyl chloride, by-products may be formed.
In order to obtain an additional information which
may be useful for prediction of the reaction pathway,
we examined reactions of (Z)-3-phenacylidene- and
* For communication XLIX, see [1].
1070-4280/05/4107-1081 © 2005 Pleiades Publishing, Inc.

BOZDYREVA et al.
1082
Scheme 1.
Ph
N
NHPh
NH2
O
O
O
AlkOCOCOOAlk
MeONa
O
OMe (OH)
R
N
H
R
Me
O
O
R
Ia–Ik
Ph
N
Ph
N
O
O
R
R
O
Ph
N
O
N
O
N
O
O
·
O
·
ClCOCOCl
[4+2]
O
O
Δ
O
COR
N
COR
N
–CO
O
N
N
O
Ph
R
IIa–IIk
O
N
Ph
D
E
Ph
O
O
~1,3-COR
N
N
N
Ph
N
O
ROCO
IIIa–IIIk
COR
R = Ph (a), 4-MeC6H4 (b), 4-MeOC6H4 (c), 4-EtOC6H4 (d), 4-FC6H4 (e), 4-ClC6H4 (f), 4-BrC6H4 (g), 4-O2NC6H4 (h), 2-furyl (i),
5-methyl-2-furyl (j), 5-chloro-2-thienyl (k).
1
(Z)-3-hetaroylmethylidene-1-phenyl-1,2,3,4-tetrahy-
droquinoxalin-2-ones Ia–Ik with oxalyl chloride.
Quinoxalinones Ia–Ik were synthesized according to
the known procedure [11] by reactions of aroyl- and
hetaroylpyruvic acids or esters derived therefrom with
N-phenyl-o-phenylenediamine (Scheme 1). Com-
pounds Ia–Ik are bright yellow high-melting crystal-
line substances. They are readily soluble in dimethyl-
formamide and dimethyl sulfoxide, poorly soluble in
common organic solvents, and insoluble in water and
saturated hydrocarbons.
region 1606–1624 cm–1). In the H NMR spectra of
solutions of Ia–Ik in DMSO-d6 we observed signals
from protons in the aromatic rings and substituents
attached thereto, a singlet from the vinyl proton
(C3=CH) at δ 6.62–6.91 ppm, and a singlet from the
N4H proton; the latter appeared in a weak field
(δ 13.37–14.05 ppm) due to formation of intramolec-
ular hydrogen bond. Among the aromatic proton
signals (δ 6.33–6.44 ppm), the doublet from 8-H in the
quinoxaline ring was displaced upfield due to shielding
by π-electrons in the benzene ring on N1, and the
doublet from two ortho-protons in the ArCO group
was displaced downfield (δ 7.89–8.33 ppm; com-
pounds Ia–Ih).
The IR spectra of compounds Ia–Ik contain absorp-
tion bands belonging to stretching vibrations of the
N–H group involved in intramolecular hydrogen bond
(a broad band in the region 3040–3070 cm–1, amide
carbonyl group (C2=O, 1670–1689 cm–1), and ketone
carbonyl groups (aroyl and hetaroyl moieties involved
in intramolecular hydrogen bond; a broad band in the
The spectral parameters of compounds Ia–Ik
indicate that they exist in crystal and in solution as the
corresponding Z isomers stabilized by a strong intra-
molecular hydrogen bond (like H-chelate) between the
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

FIVE-MEMBERED 2,3-DIOXO HETEROCYCLES: L.
1083
N4H proton and side-chain carbonyl group; such hy-
drogen bonding is typical of these compounds [4, 11].
with published data for monocyclic 2,3-dihydropyr-
role-2,3-diones [12] and isatins [13].
1
Quinoxalinones Ia–Ik were treated with oxalyl
chloride on heating for 1 h in boiling anhydrous ben-
zene. As a result, we obtained in almost quantitative
yields representatives of a new class of 4-acyl-2,3-
dihydropyrrole-2,3-diones fused through the [a] side
with aza heterocycles, 3-aroyl- and 3-hetaroyl-5-phen-
yl-1,2,4,5-tetrahydropyrrolo[1,2-a]quinoxaline-1,2,4-
triones IIa–IIk (Scheme 1). Compounds IIa–IIk were
isolated as dark violet (almost black) crystalline sub-
stances with high melting points (with decomposition).
The products are readily soluble in DMF and DMSO,
poorly soluble in common aprotic organic solvents,
and insoluble in alkanes. Compounds IIa–IIk reacted
with water and alcohols and lose their color on storage
due to hydrolysis by atmospheric moisture.
The H NMR spectra of IIa–IIk in DMSO-d6 con-
tained signals from aromatic protons and substituents
in the aromatic rings. The doublet from the 6-H proton
was located in a strong field, δ 6.36–6.45 ppm, due to
shielding by π-electrons of the benzene ring on N5,
while the doublet from two ortho-protons in the ArCO
group (δ 7.82–8.07 ppm, compounds IIa–IIh) and the
doublet from 9-H (deshielded by the C1=O group;
δ 8.01–8.56 ppm) were observed in a weak field.
It is known that stabilization of acyl(imidoyl)-
ketenes generated by thermal decarbonylation of sub-
stituted 2,3-dihydropyrrole-2,3-diones and 2,3-dihydro-
furan-2,3-diones can follow different paths, depending
on the substituent in the dioxo heterocycle. Two stabi-
lization pathways were reported for acyl(imidoyl)-
ketenes in which the imidoyl fragment constitutes
a part of a heterocyclic system (Scheme 2). Ethoxycar-
bonyl(3-oxo-3,4-dihydroquinoxalin-2-yl)ketene A sta-
bilizes via transformation of the quinoxalinone frag-
ment from the amide to hydroxyimino form, followed
by intramolecular acylation of the hydroxyimino group
by the ketene moiety [14]. Aroyl(2-oxo-3,4-dihydro-
2H-1,4-benzoxazin-2-yl)ketenes B and aroyl(3-aryl-
quinoxalin-2-yl)ketenes C undergo [4+2]-cyclodi-
merization where one ketene molecule acts as diene
(imidoylketene fragment), and the other, as dienophile
Pyrroloquinoxalines IIa–IIk showed in the IR
spectra absorption bands at 1760–1775 cm–1 due to
stretching vibrations of the lactam carbonyl group
(C1=O), 1721–1740 cm–1 (ketone carbonyl group
C2=O), 1682–1700 cm–1 (amide carbonyl C4=O), and
1638–1670 cm–1 (side-chain ketone carbonyl group).
The frequency ranges corresponding to stretching
vibrations of the carbonyl groups in the pyrroledione
fragment, as well as the higher frequency of stretching
vibrations of the lactam carbonyl group as compared to
the endocyclic ketone carbonyl group, are consistent
Scheme 2.
O
N
O
H
N
O
Ar
COAr
O
R
N
N
N
OH
OEt
N
O
O
R = OEt
R = Ar
COAr
·
O
O
N
·
O
A–C
~1,3-COAr
COAr
N
O
O
N
N
H
O
OCOAr
N
COOEt
A, R = OEt; B, C, R = Ar.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

BOZDYREVA et al.
1084
(ketene C=C bond) [15, 16]; next follows thermal
[1,3]-migration of the aroyl group in the primary
cycloadduct.
ducts E are stabilized via [1,3]-C–O migration of the
acyl group, which is typical of ketenes like B and C
[15, 16]. The described reaction may be regarded as
a convenient and regioselective method for building
up difficultly accessible functionalized pyrido[1,2-a]-
quinoxaline system.
Intramolecular cyclization like that described in
[14] is impossible (for structural reasons) for aroyl-
and hetaroyl(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-
yl)ketenes D which are expected to be formed as
a result of thermal decarbonylation of 3-aroyl- and
3-hetaroyl-5-phenyl-1,2,4,5-tetrahydropyrrolo[1,2-a]-
quinoxaline-1,2,4-triones IIa–IIk (Scheme 1). How-
ever, there are alternatives for participation in inter-
molecular reactions through both acylketene and imid-
oylketene fragments.
EXPERIMENTAL
The IR spectra were recorded on a UR-20 spec-
trometer from samples dispersed in mineral oil. The
1H and 13C NMR spectra were measured at the Ural–
YaMR Center (Russian Foundation for Basic Research
project no. 00-03-40139) on a Bruker AM-400 instru-
1
When pyrroloquinoxalinetriones IIa–IIk were
heated for 30–60 min at 172–173°C in an inert aprotic
solvent (decane or decane–Dowtherm A, 5:1), we ob-
tained in good yields 4-acyl-3-acyloxy-2-(3-oxo-4-
phenyl-3,4-dihydroquinoxalin-2-yl)-6-phenyl-5,6-di-
hydro-1H-pyrido[1,2-a]quinoxaline-1,5-diones IIIa–
IIIk [17] (Scheme 1). According to the TLC data, the
reaction mixtures contained traces of initial quinoxa-
linones Ia–Ik; presumably, they were formed by
hydrolysis of pyrroloquinoxalinetriones IIa–IIk with
traces of water present in the solvent. Compounds
IIIa–IIIk are yellow high-melting crystalline sub-
stances which melt with decomposition and are readily
soluble in DMF and DMSO, poorly soluble in com-
mon organic solvents, and insoluble in water and
saturated hydrocarbons.
ment (400 MHz for H) from solutions in DMSO-d6
using tetramethylsilane as internal reference. The
purity of the products was checked by thin-layer
chromatography on Silufol plates using ethyl acetate,
ethyl acetate–benzene (1:5), and benzene as eluents;
spots were visualized by treatment with iodine vapor
or under UV light.
(Z)-3-Phenacylidene-1-phenyl-1,2,3,4-tetra-
hydroquinoxalin-2-one (Ia). A solution of 2.00 g
(9.7 mmol) of methyl 2,4-dioxo-4-phenyl-2-butenoate
and 1.79 g (9.7 mmol) of N-phenyl-o-phenylenedi-
amine in 50 ml of 2-propanol was heated for 60 min
under reflux. The mixture was cooled, and the precip-
itate was filtered off and recrystallized from ethyl
acetate. Yield 2.41 g (73%), mp 217–218°C; published
data [4]: mp 212–213°C. IR spectrum, ν, cm–1: 1610 br
1
(COPh), 1670 (C2=O), 3060 br (NH). H NMR spec-
The IR spectra of IIIa–IIIk contained absorption
bands due to stretching vibrations of the ester carbonyl
group (1759–1770 cm–1) and amide and aroyl
(hetaroyl) carbonyl groups (one or two broad bands
in the region 1656–1680 cm–1). Compounds IIIa–IIIk
trum, δ, ppm: 6.40 d (1H, 8-H, J = 8.0 Hz), 6.89 s (1H,
C3=CH), 7.01–7.70 m (11H, Harom), 7.99 d (2H, o-H in
PhCO, J = 8.7 Hz), 13.91 s (NH). Found, %: C 77.68;
H 4.70; N 8.22. C22H16N2O2. Calculated, %: C 77.63;
H 4.74; N 8.23.
1
showed in the H NMR spectra signals from aromatic
protons and protons in the substituents attached to
aromatic rings. The doublet signals from 7-H and 5'-H
appeared in a strong field (δ 6.52–6.55 and 6.65–
6.87 ppm, respectively) due to shielding by p-electrons
in the benzene rings on the nitrogen atoms. The 10-H
proton is deshielded due to interaction with the C1=O
carbonyl group, and its signal is displaced downfield
(δ 9.05–9.20 ppm). The spectral parameters of com-
pounds IIIa–IIIk are similar to structurally related
dimers derived from ketenes B and C; the structure of
the latter was proved by X-ray analysis [15, 16].
Compounds Ib–Ik were synthesized in a similar
way.
(Z)-3-(4-Methylphenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Ib). Yield 2.83 g (80%),
mp 206–207°C (from ethyl acetate); published data
[18]: mp 205–207°C. IR spectrum, ν, cm–1: 1613 br
1
(COAr), 1689 (C2=O), 3040 br (NH). H NMR spec-
trum, δ, ppm: 2.49 s (3H, Me), 6.39 d (1H, 8-H, J =
8.1 Hz), 6.86 s (1H, C3=CH), 6.99–7.70 m (10H, Harom),
7.89 d (2H, o-H in ArCO, J = 8.8 Hz), 13.89 s (NH).
Found, %: C 77.99; H 5.14; N 7.88. C23H18N2O2. Cal-
culated, %: C 77.95; H 5.12; N 7.90.
Presumably, ketenes D undergo [4+2]-cyclodi-
merization through the imidoylketene fragment in
a way similar to that reported in [15, 16], provided that
no other partner is present. Primary [4+2]-cycload-
(Z)-3-(4-Methoxyphenacylidene)-1-phenyl-
1,2,3,4-tetrahydroquinoxalin-2-one (Ic). Yield 2.37 g
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

FIVE-MEMBERED 2,3-DIOXO HETEROCYCLES: L.
1085
(64%), mp 218–219°C (from ethyl acetate). IR spec-
cm–1: 1612 br (COAr), 1687 (C2=O), 3050 br (NH).
1H NMR spectrum, δ, ppm: 6.44 d (1H, 8-H, J =
7.9 Hz), 6.91 s (1H, C3=CH), 7.05–7.70 m (10H,
Harom), 8.33 d (2H, o-H in ArCO, J = 8.6 Hz), 8.34 d
(2H, m-H in ArCO, J = 9.1 Hz), 14.05 s (NH). Found,
%: C 68.59; H 3.90; N 10.94. C22H15N3O4. Calculated,
%: C 68.57; H 3.92; N 10.90.
trum, ν, cm–1: 1620 br (COAr), 1688 (C2=O), 3040 br
1
(NH). H NMR spectrum, δ, ppm: 2.49 s (3H, Me),
6.39 d (1H, 8-H, J = 8.1 Hz), 6.86 s (1H, C3=CH),
6.99–7.70 m (10H, Harom), 7.89 d (2H, o-H in ArCO,
J = 8.8 Hz), 13.89 s (NH). Found, %: C 74.54; H 5.07;
N 7.59. C23H18N2O3. Calculated, %: C 74.58; H 5.00;
N 7.56.
(Z)-3-(2-Furoylmethylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Ii). Yield 2.75 g (86%),
mp 242–243°C (from ethyl acetate). IR spectrum, ν,
cm–1: 1625 br (COHt), 1677 (C2=O), 3040 br (NH).
1H NMR spectrum, δ, ppm: 6.34 d (1H, 8-H, J =
8.3 Hz), 6.69 s (1H, C3=CH), 6.71–7.64 m (11H,
(Z)-3-(4-Ethoxyphenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Id). Yield 2.92 g (76%),
mp 204–205°C (from ethyl acetate). IR spectrum, ν,
cm–1: 1606 br (COAr), 1680 (C2=O), 3050 br (NH).
1H NMR spectrum, δ, ppm: 1.36 t (3H, Me), 4.12 q
(2H, CH2O), 6.33 d (1H, 8-H, J = 8.1 Hz), 6.83 s (1H,
C3=CH), 7.00–7.67 m (10H, Harom), 7.96 d (2H, o-H in
ArCO, J = 8.8 Hz), 13.77 s (NH). Found, %: C 74.96;
H 5.27; N 7.28. C24H20N2O3. Calculated, %: C 74.98;
H 5.24; N 7.29.
H
arom), 13.45 s (NH). Found, %: C 72.69; H 4.28;
N 8.45. C20H14N2O3. Calculated, %: C 72.72; H 4.27;
N 8.48.
(Z)-3-(5-Methyl-2-furoylmethylidene)-1-phenyl-
1,2,3,4-tetrahydroquinoxalin-2-one (Ij). Yield 2.44 g
(71%), mp 212–214°C (from ethyl acetate). IR spec-
trum, ν, cm–1: 1624 br (COHt), 1685 (C2=O), 3040 br
(Z)-3-(4-Fluorophenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Ie). Yield 2.54 g (71%),
mp 204–205°C (from ethyl acetate). IR spectrum, ν,
cm–1: 1608 br (COAr), 1683 (C2=O), 3070 br (NH).
1H NMR spectrum, δ, ppm: 6.40 d (1H, 8-H, J =
7.9 Hz), 6.84 s (1H, C3=CH), 7.01–7.68 m (10H, Harom),
8.07 d (2H, o-H in ArCO, J = 8.9 Hz), 13.82 s (NH).
Found, %: C 73.77; H 4.20; N 7.83. C22H15FN2O2. Cal-
culated, %: C 73.73; H 4.22; N 7.82.
1
(NH). H NMR spectrum, δ, ppm: 2.40 s (3H, Me),
6.34 d (1H, 8-H, J = 8.2 Hz), 6.62 s (1H, C3=CH),
6.36–7.64 m (10H, Harom), 13.42 s (NH). Found, %:
C 73.22; H 4.66; N 8.14. C21H16N2O3. Calculated, %:
C 73.24; H 4.68; N 8.13.
(Z)-3-(5-Chloro-2-thenoylmethylidene)-1-phenyl-
1,2,3,4-tetrahydroquinoxalin-2-one (Ik). Yield 1.66 g
(72%), mp 250–251°C (from ethyl acetate). IR spec-
trum, ν, cm–1: 1618 br (COHt), 1675 (C2=O), 3050 br
(Z)-3-(4-Chlorophenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (If). Yield 1.87 g (50%),
mp 212–213°C (from ethyl acetate); published data
[4]: mp 211–213°C. IR spectrum, ν, cm–1: 1620 br
1
(NH). H NMR spectrum, δ, ppm: 6.35 d (1H, 8-H,
J = 8.3 Hz), 6.69 s (1H, C3=CH), 7.04–7.82 m (10H,
1
(COAr), 1686 (C2=O), 3050 br (NH). H NMR spec-
H
arom), 13.37 s (NH). Found, %: C 63.08; H 3.43;
trum, δ, ppm: 6.35 d (1H, 8-H, J = 8.3 Hz), 6.85 s (1H,
C3=CH), 7.06–7.68 m (10H, Harom), 8.01 d (2H, o-H in
ArCO, J = 8.7 Hz), 13.84 s (NH). Found, %: C 70.50;
H 4.06; Cl 9.44; N 7.45. C22H15ClN2O2. Calculated, %:
C 70.50; H 4.03; Cl 9.46; N 7.47.
Cl 9.32; N 7.38; S 8.44. C20H13ClN2O2S. Calculated,
%: C 63.07; H 3.44; Cl 9.31; N 7.35; S 8.42.
3-Benzoyl-5-phenyl-1,2,4,5-tetrahydropyrrolo-
[1,2-a]quinoxaline-1,2,4-trione (IIa). A solution of
1.72 g (0.005 mol) of compound Ia and 0.45 ml
(0.00525 mol) of oxalyl chloride in 30 ml of anhydrous
benzene was heated for 60 min under reflux (until
the originally yellow solution turned dark violet). The
mixture was cooled, and the precipitate was filtered
off. Yield 1.16 g (59%), mp 224–227°C (from ben-
zene, decomp.); published data [18]: mp 210–211°C.
IR spectrum, ν, cm–1: 1660 (C3=O), 1682 (C4=O), 1721
(Z)-3-(4-Bromophenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Ig). Yield 1.84 g (44%),
mp 242–243°C (from ethyl acetate). IR spectrum, ν,
cm–1: 1620 br (COAr), 1684 (C2=O), 3040 br (NH).
1H NMR spectrum, δ, ppm: 6.36 d (1H, 8-H, J =
7.8 Hz), 6.85 s (1H, C3=CH), 7.06–7.74 m (10H, Harom),
7.93 d (2H, o-H in ArCO, J = 8.6 Hz), 13.85 s (NH).
Found, %: C 63.02; H 3.61; Br 19.06; N 6.68.
C22H15BrN2O2. Calculated, %: C 63.04; H 3.62;
Br 19.08; N 6.67.
1
(C2=O), 1760 (C1=O). H NMR spectrum, δ, ppm:
6.36 d (1H, 6-H, J = 8.2 Hz), 7.05–7.82 m (12H, Harom
,
7-H, 8-H), 8.01 d (1H, 9-H, J = 7.2 Hz). Found, %:
C 73.08; H 3.57; N 7.14. C24H14N2O4. Calculated, %:
C 73.09; H 3.58; N 7.10.
(Z)-3-(4-Nitrophenacylidene)-1-phenyl-1,2,3,4-
tetrahydroquinoxalin-2-one (Ih). Yield 2.35 g (61%),
mp 226–227°C (from ethyl acetate). IR spectrum, ν,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

BOZDYREVA et al.
1086
1
Compounds IIb–IIk were synthesized in a similar
way.
3-(4-Methylbenzoyl)-5-phenyl-1,2,4,5-tetra-
(C4=O), 1740 (C2=O), 1771 (C1=O). H NMR spec-
trum, δ, ppm: 6.41 d (1H, 6-H, J = 8.2 Hz), 7.05–
7.82 m (9H, Harom, m-H in ArCO, 7-H, 8-H), 8.07 d
(2H, o-H in ArCO, J = 8.7 Hz), 8.56 d (1H, 9-H, J =
8.1 Hz). Found, %: C 67.22; H 3.09; Cl 8.25; N 6.56.
C24H13ClN2O4. Calculated, %: C 67.22; H 3.06;
Cl 8.27; N 6.53.
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIb).
Yield 1.83 g (90%), mp 207–209°C (from benzene,
decomp.); published data [18]: mp 208–210°C (from
dichloroethane). IR spectrum, ν, cm–1: 1661 (C3=O),
1
1698 (C4=O), 1731 (C2=O), 1770 (C1=O). H NMR
3-(4-Bromobenzoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIg).
Yield 2.10 g (89%), mp 216–218°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1670 (C3=O), 1697
spectrum, δ, ppm: 2.40 s (3H, Me), 6.41 d (1H, 6-H,
J = 8.1 Hz), 7.05–7.75 m (9H, Harom, m-H in ArCO,
7-H, 8-H), 7.85 d (2H, o-H in ArCO, J = 7.9 Hz),
8.55 d (1H, 9-H, J = 7.6 Hz). Found, %: C 73.58;
H 3.98; N 6.86. C25H16N2O4. Calculated, %: C 73.52;
H 3.95; N 6.86.
1
(C4=O), 1744 (C2=O), 1777 (C1=O). H NMR spec-
trum, δ, ppm: 6.39 d (1H, 6-H, J = 8.3 Hz), 7.11–
7.88 m (9H, Harom, m-H in ArCO, 7-H, 8-H), 8.01 d
(2H, o-H in ArCO, J = 8.9 Hz), 8.54 d (1H, 9-H, J =
8.3 Hz). Found, %: C 60.90; H 2.74; Br 16.86; N 5.96.
C24H13BrN2O4. Calculated, %: C 60.91; H 2.77;
Br 16.88; N 5.92.
3-(4-Methoxybenzoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIc).
Yield 1.86 g (88%), mp 199–200°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1652 (C3=O), 1698
1
(C4=O), 1732 (C2=O), 1774 (C1=O). H NMR spec-
3-(4-Nitrobenzoyl)-5-phenyl-1,2,4,5-tetrahydro-
pyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIh). Yield
2.08 g (95%), mp 201–203°C (from benzene, decomp.).
IR spectrum, ν, cm–1: 1666 (C3=O), 1690 (C4=O), 1739
trum, δ, ppm: 3.83 s (3H, Me), 6.37 d (1H, 6-H, J =
8.0 Hz), 6.98–7.89 m (9H, Harom, m-H in ArCO, 7-H,
8-H), 8.03 d (2H, o-H in ArCO, J = 7.8 Hz), 8.53 d
(1H, 9-H, J = 7.8 Hz). Found, %: C 70.77; H 3.83;
N 6.57. C25H16N2O5. Calculated, %: C 70.75; H 3.80;
N 6.60.
(C2=O), 1775 (C1=O). H NMR spectrum, δ, ppm:
1
6.42 d (1H, 6-H, J = 8.2 Hz), 7.10–8.38 m (11H, Harom
,
o-H and m-H in ArCO, 7-H, 8-H), 8.52 d (1H, 9-H,
J = 8.0 Hz). Found, %: C 65.63; H 2.96; N 9.53.
C24H13N3O6. Calculated, %: C 65.61; H 2.98; N 9.56.
3-(4-Ethoxybenzoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IId).
Yield 1.92 g (88%), mp 203–205°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1653 (C3=O), 1696
3-(2-Furoyl)-5-phenyl-1,2,4,5-tetrahydropyrrolo-
[1,2-a]quinoxaline-1,2,4-trione (IIi). Yield 1.84 g
(96%), mp 194–196°C (from benzene, decomp.). IR
spectrum, ν, cm–1: 1629 (C3=O), 1680 (C4=O), 1721
1
(C4=O), 1728 (C2=O), 1769 (C1=O). H NMR spec-
trum, δ, ppm: 1.29 t (3H, Me), 4.23 q (2H, CH2O),
1
6.45 d (1H, 6-H, J = 8.1 Hz), 7.04–7.60 m (9H, Harom
,
(C2=O), 1763 (C1=O). H NMR spectrum, δ, ppm:
m-H in ArCO, 7-H, 8-H), 7.82 d (2H, o-H in ArCO,
J = 7.9 Hz), 8.50 d (1H, 9-H, J = 7.7 Hz). Found, %:
C 71.20; H 4.15; N 6.36. C26H18N2O5. Calculated, %:
C 71.23; H 4.14; N 6.39.
6.40 d (1H, 6-H, J = 8.3 Hz), 6.68–8.03 m (10H,
Harom), 8.53 d (1H, 9-H, J = 7.1 Hz). Found, %:
C 68.77; H 3.14; N 7.25. C22H12N2O5. Calculated, %:
C 68.75; H 3.15; N 7.29.
3-(4-Fluorobenzoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIe).
Yield 2.02 g (98%), mp 210–211°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1660 (C3=O), 1697
3-(5-Methyl-2-furoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIj).
Yield 1.95 g (98%), mp 200–202°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1638 (C3=O), 1700
1
1
(C4=O), 1735 (C2=O), 1770 (C1=O). H NMR spec-
(C4=O), 1735 (C2=O), 1772 (C1=O). H NMR spec-
trum, δ, ppm: 6.40 d (1H, 6-H, J = 8.4 Hz), 7.05–
7.92 m (11H, Harom, m-H in ArCO, 7-H, 8-H, o-H in
ArCO), 8.56 d (1H, 9-H, J = 8.3 Hz). Found, %:
C 69.91; H 3.16; N 6.82. C24H13FN2O4. Calculated, %:
C 69.90; H 3.18; N 6.79.
trum, δ, ppm: 2.36 s (3H, Me), 6.34 d (1H, 6-H, J =
8.1 Hz), 6.38–7.87 m (9H, Harom), 8.53 d (1H, 9-H,
J = 8.4 Hz). Found, %: C 69.36; H 3.55; N 7.01.
C23H14N2O5. Calculated, %: C 69.35; H 3.54; N 7.03.
3-(5-Chloro-2-thenoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIk).
Yield 2.13 g (98%), mp 208–209°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1632 (C3=O), 1684
3-(4-Chlorobenzoyl)-5-phenyl-1,2,4,5-tetra-
hydropyrrolo[1,2-a]quinoxaline-1,2,4-trione (IIf).
Yield 2.03 g (95%), mp 211–212°C (from benzene,
decomp.). IR spectrum, ν, cm–1: 1665 (C3=O), 1689
1
(C4=O), 1723 (C2=O), 1770 (C1=O). H NMR spec-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

FIVE-MEMBERED 2,3-DIOXO HETEROCYCLES: L.
1087
trum, δ, ppm: 6.40 d (1H, 6-H, J = 8.2 Hz), 7.12–
8.03 m (9H, Harom), 8.53 d (1H, 9-H, J = 8.3 Hz).
Found, %: C 60.76; H 2.56; Cl 8.17; N 6.40; S 7.39.
C22H11ClN2O4S. Calculated, %: C 60.77; H 2.55;
Cl 8.15; N 6.44; S 7.37.
1,5-dione (IIId). Yield 0.66 g (73%), mp 278–279°C
(from DMSO, decomp.). IR spectrum, ν, cm–1: 1680 br
1
(CON, C4–CO), 1765 (COO). H NMR spectrum, δ,
ppm: 1.32 t (3H, Me, J = 7.0 Hz), 1.35 t (3H, Me,
J = 7.0 Hz), 4.01 q (2H, CH2O, J = 7.0 Hz), 4.01 q
(2H, CH2O, J = 7.0 Hz), 6.54 d (1H, 7-H, J = 8.3 Hz),
6.59 d (1H, 5'-H, J = 8.3 Hz), 7.18–7.86 m (23H,
Harom), 9.18 (1H, 10-H, J = 8.1 Hz). Found, %: C 73.15;
H 4.44; N 6.80. C50H36N4O8. Calculated, %: C 73.16;
H 4.42; N 6.83.
4-Benzoyl-3-benzoyloxy-2-(3-oxo-4-phenyl-3,4-
dihydroquinoxalin-2-yl)-6-phenyl-5,6-dihydro-1H-
pyrido[1,2-a]quinoxaline-1,5-dione (IIIa). A solution
of 1.00 g (2.5 mmol) of compound IIa in 20 ml of
decane was heated for 60 min at 172–173°C (until the
originally violet solution turned yellow). The mixture
was cooled, and the precipitate was filtered off and
recrystallized from acetonitrile–dichloroethane (1:1).
Yield 0.73 g (78%), mp 329–330°C (decomp.). IR
spectrum, ν, cm–1: 1670 br, 1680 (CON, C4–CO); 1749
4-(4-Fluorobenzoyl)-3-(4-fluorobenzoyloxy)-2-(3-
oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-phenyl-
5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-1,5-dione
(IIIe). Yield 0.67 g (72%), mp 293–294°C (from
acetonitrile, decomp.). IR spectrum, ν, cm–1: 1670 br
1
(CON, C4–CO), 1750 (COO). H NMR spectrum, δ,
1
(COO). H NMR spectrum, δ, ppm: 6.54 d (1H, 7-H,
ppm: 6.55 d (1H, 7-H, J = 7.2 Hz), 6.63 d (1H, 5'-H,
J = 8.2 Hz), 7.05–7.99 m (23H, Harom), 9.20 (1H, 10-H,
J = 8.0 Hz). Found, %: C 71.85; H 3.45; N 7.27.
C46H26F2N4O6. Calculated, %: C 71.87; H 3.41; N 7.29.
J = 7.8 Hz), 6.60 d (1H, 5'-H, J = 8.3 Hz), 7.24–7.98 m
(25H, Harom), 9.21 d (1H, 10-H, J = 7.6 Hz). 13C NMR
spectrum, δC, ppm: 115.13–136.90 (Carom); 151.72,
154.90, 160.40, 161.69 (C1, C3–O–C=O, C5, C3');
189.10 (C4–C=O). Found, %: C 75.43; H 3.87; N 7.65.
C46H28N4O6. Calculated, %: C 75.40; H 3.85; N 7.66.
4-(4-Chlorobenzoyl)-3-(4-chlorobenzoyloxy)-
2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-
phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
1,5-dione (IIIf). Yield 0.65 g (69%), mp 338–340°C
(from acetonitrile, decomp.). IR spectrum, ν, cm–1:
Compounds IIIb–IIIk were synthesized in a simi-
lar way.
1
1670 br (CON, C4–CO), 1760 (COO). H NMR spec-
4-(4-Methylbenzoyl)-3-(4-methylbenzoyloxy)-
2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-
phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
1,5-dione (IIIb). Yield 1.29 g (69%), mp 244–245°C
(from acetonitrile, decomp.). IR spectrum, ν, cm–1:
trum, δ, ppm: 6.53 d (1H, 7-H, J = 7.8 Hz), 6.55 d (1H,
5'-H, J = 8.0 Hz), 7.25–7.98 m (23H, Harom), 9.18 d
(1H, 10-H, J = 7.9 Hz). Found, %: C 68.93; H 2.28;
Cl 8.88; N 6.95. C46H26Cl2N4O6. Calculated, %:
C 68.92; H 2.27; Cl 8.85; N 6.99.
1
1670 br (CON, C4–CO), 1770 (COO). H NMR spec-
trum, δ, ppm: 2.30 s (3H, Me), 2.39 s (3H, Me), 6.52 d
(1H, 7-H, J = 8.3 Hz), 6.58 d (1H, 5'-H, J = 8.6 Hz),
7.16–7.85 m (23H, Harom), 9.17 d (1H, 10-H, J = 7.9 Hz).
Found, %: C 75.76; H 4.26; N 7.33. C48H32N4O6. Cal-
culated, %: C 75.78; H 4.24; N 7.36.
4-(4-Bromobenzoyl)-3-(4-bromobenzoyloxy)-
2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-
phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
1,5-dione (IIIg). Yield 0.68 g (72%), mp 310–311°C
(from acetonitrile, decomp.). IR spectrum, ν, cm–1:
1
1676 br (CON, C4–CO), 1759 (COO). H NMR spec-
4-(4-Methoxybenzoyl)-3-(4-methoxybenzoyloxy)-
2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-
6-phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
1,5-dione (IIIc). Yield 0.65 g (70%), mp 319–321°C
(from acetonitrile, decomp.). IR spectrum, ν, cm–1:
trum, δ, ppm: 6.53 d (1H, 7-H, J = 7.6 Hz), 6.59 d (1H,
5'-H, J = 8.0 Hz), 7.26–7.90 m (23H, Harom), 9.18 d
(1H, 10-H, J = 7.9 Hz). Found, %: C 62.09; H 2.97;
Br 17.90; N 6.28. C46H26BrN4O6. Calculated, %:
C 62.04; H 2.94; Br 17.95; N 6.29.
1
1668 br, 1680 (CON, C4–CO); 1750 (COO). H NMR
spectrum, δ, ppm: 3.77 s (3H, MeO), 3.90 s (3H,
MeO), 6.52 d (1H, 7-H, J = 7.7 Hz), 6.58 d (1H, 5'-H,
J = 7.7 Hz), 7.18–7.83 m (23H, Harom), 9.16 (1H, 10-H,
J = 8.2 Hz). Found, %: C 72.75; H 4.09; N 7.06.
C48H32N4O8. Calculated, %: C 72.72; H 4.07; N 7.07.
4-(4-Nitrobenzoyl)-3-(4-nitrobenzoyl)-2-(3-oxo-
4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-phenyl-5,6-
dihydro-1H-pyrido[1,2-a]quinoxaline-1,5-dione
(IIIh). Yield 0.64 g (68%), mp 314–315°C (from ben-
zene, decomp.). IR spectrum, ν, cm–1: 1680 br (CON,
1
4-(4-Ethoxybenzoyl)-3-(4-ethoxybenzoyloxy)-2-
(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-6-
phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
C4–CO), 1760 (COO). H NMR spectrum, δ, ppm:
6.57 d (1H, 7-H, J = 6.1 Hz), 6.63 d (1H, 5'-H, J =
8.2 Hz), 7.17–8.30 m (23H, Harom), 9.23 d (1H, 10-H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005

BOZDYREVA et al.
1088
3. Sano, T., Toda, J., Maehara, N., and Tsuda, Y., Can. J.
Chem., 1987, vol. 65, p. 94.
J = 8.2 Hz). Found, %: C 67.18; H 3.15; N 10.22.
C46H26N6O10. Calculated, %: C 67.15; H 3.19; N 10.21.
4. Maslivets, A.N., Mashevskaya, I.V., Krasnykh, O.P.,
Shurov, S.N., and Andreichikov, Yu.S., Zh. Org. Khim.,
1992, vol. 28, p. 2545.
5. Kollenz, G., Theuer, R., Ott, W., and Ziegler, E., Justus
Liebigs Ann. Chem., 1997, p. 1964.
6. Kistanova, N.S., Mashevskaya, I.V., Bozdyreva, K.S.,
and Maslivets, A.N., Khim. Geterotsikl. Soedin., 2003,
p. 773.
7. Maslivets, A.N., Lisovenko, N.Yu., Golovnina, O.V.,
Vostrov, E.S., and Tarasova, O.P., Khim. Geterotsikl.
Soedin., 2000, no. 4, p. 556.
4-(2-Furoyl)-3-(2-furoyloxy)-2-(3-oxo-4-phenyl-
3,4-dihydroquinoxalin-2-yl)-6-phenyl-5,6-dihydro-
1H-pyrido[1,2-a]quinoxaline-1,5-dione (IIIi). Yield
0.62 g (67%), mp 320–321°C (from toluene, decomp.).
IR spectrum, ν, cm–1: 1665 br (CON, C4–CO), 1755
1
(COO). H NMR spectrum, δ, ppm: 6.45 d (1H, 7-H,
J = 7.5 Hz), 6.65 d (1H, 5'-H, J = 7.5 Hz), 7.17–7.88 m
(21H, Harom), 9.15 d (1H, 10-H, J = 8.3 Hz). Found, %:
C 70.77; H 3.37; N 7.87. C42H24N4O8. Calculated, %:
C 70.79; H 3.39; N 7.86.
8. Aliev, Z.G., Maslivets, A.N., Golovnina, O.V., Kras-
nykh, O.P., and Atovmyan, L.O., Zh. Strukt. Khim.,
2002, vol. 43, p. 576.
9. Vostrov, E.S. and Maslivets, A.N., Trudy vtoroi mezhdu-
narodnoi konferentsii “Khimiya i biologicheskaya aktiv-
nost’ kislorod- i serusoderzhashchikh geterotsiklov”
(Proc. 2nd Int. Conf. “Chemistry and Biological Activ-
ity of Oxygen- and Sulfur-Containing Heterocycles”),
Moscow: IBS, 2003, vol. 2, p. 270.
10. Lisovenko, N.Yu. and Maslivets, A.N., Trudy vtoroi
mezhdunarodnoi konferentsii “Khimiya i biologiche-
skaya aktivnost’ kislorod- i serusoderzhashchikh getero-
tsiklov” (Proc. 2nd Int. Conf. “Chemistry and Biological
Activity of Oxygen- and Sulfur-Containing Hetero-
cycles”), Moscow: IBS, 2003, vol. 2, p. 134.
4-(5-Methyl-2-furoyl)-3-(5-methyl-2-furoyloxy)-
2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-yl)-
6-phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxaline-
1,5-dione (IIIj). Yield 0.67 g (72%), mp 325–327°C
(from toluene, decomp.). IR spectrum, ν, cm–1: 1656 br,
1
1682 (CON, C4–CO); 1759 (COO). H NMR spec-
trum, δ, ppm: 6.35 d (1H, 7-H, J = 8.3 Hz), 6.55 d (1H,
5'-H, J = 8.2 Hz), 6.87–7.85 m (19H, Harom), 9.05 d
(1H, 10-H, J = 8.3 Hz). Found, %: C 71.36; H 3.84;
N 7.58. C44H28N4O8. Calculated, %: C 71.35; H 3.81;
N 7.56.
4-(5-Chloro-2-thenoyl)-3-(5-chloro-2-thenoyl-
oxy)-2-(3-oxo-4-phenyl-3,4-dihydroquinoxalin-2-
yl)-6-phenyl-5,6-dihydro-1H-pyrido[1,2-a]quinoxa-
line-1,5-dione (IIIk). Yield 0.65 g (70%), mp 323–
324°C (from toluene, decomp.). IR spectrum, ν, cm–1:
11. Maslivets, A.N., Smirnova, L.I., and Andreichi-
kov, Yu.S., Zh. Org. Khim., 1992, vol. 28, p. 2141.
12. Andreichikov, Yu.S., Maslivets, A.N., Smirnova, L.I.,
Krasnykh, O.P., Kozlov, A.P., and Perevozchikov, L.A.,
Zh. Org. Khim., 1987, vol. 23, p. 1534.
13. Zhungietu, G.I. and Rekhter, M.A., Izatin i ego
proizvodnye (Isatin and Its Derivatives), Kishinev:
Shtiintsa, 1977, p. 228.
1
1660 br, 1680 (CON, C4–CO); 1765 (COO). H NMR
spectrum, δ, ppm: 6.46 d (1H, 7-H, J = 7.3 Hz), 6.66 d
(1H, 5'-H, J = 7.9 Hz), 7.19–7.94 m (19H, Harom), 9.17 d
(1H, 10-H, J = 8.2 Hz). Found, %: C 62.06; H 2.75;
Cl 8.70; N 6.84; S 7.94. C42H22Cl2N4O6S2. Calcu-
lated, %: C 62.00; H 2.73; Cl 8.71; N 6.89; S 7.88.
14. Maslivets, A.N., Golovnina, O.V., Krasnykh, O.P., and
Aliev, Z.G., Khim. Geterotsikl. Soedin., 2000, p. 418.
This study was performed under financial support
by the Russian Foundation for Basic Research (project
nos. 04-03-33024 and 04-03-96033).
15. Aliev, Z.G., Krasnykh, O.P., Maslivets, A.N., Andrei-
chikov, Yu.S., and Atovmyan, L.O., Izv. Ross. Akad.
Nauk, Ser. Khim., 1999, p. 2154.
16. Maslivets, A.N., Lisovenko, N.Yu., Krasnykh, O.P.,
Tarasova, O.P., Aliev, Z.G., and Atovmyan, L.O., Izv.
Ross. Akad. Nauk, Ser. Khim., 2002, p. 785.
17. Maslivets, A.N., Bozdyreva, K.S., Smirnova, I.V.,
Tolmacheva, I.A., and Mashevskaya, I.V., Khim. Gete-
rotsikl. Soedin., 2002, p. 563.
18. Mashevskaya, I.V., Makhmudov, R.R., Aleksandro-
va, G.A., Golovnina, O.V., Duvalov, A.V., and Masli-
vets, A.N., Khim.-Farm. Zh. 2001, vol. 35, p. 20.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 7 2005