Two methods for generation of aroyl(quinoxalin-2-yl)ketene

Full text of DOI:10.1134/S1070428012090229

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 9, pp. 1261–1262. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © P.S. Silaichev, A.N. Maslivets, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 9, pp. 1261–1262.
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Two Methods for Generation of Aroyl(quinoxalin-2-yl)ketene
P. S. Silaicheva, b and A. N. Maslivetsa, b
a Institute of Natural Science, Perm State National Research University,
ul. Genkelya 4, Perm, 614990 Russia
e-mail: koh2@psu.ru
b Perm State National Research University, Perm, Russia
Received July 18, 2011
DOI: 10.1134/S1070428012090229
By heating a solution of 3-(4-chlorobenzoyl)-4-(4-
chlorophenyl)pyrrolo[1,2-a]quinoxaline-1,2-dione (I)
[1] in boiling anhydrous 1,2,4-trimethylbenzene
(pseudocumene, 169–170°C) or a solution of
5-(4-chlorophenyl)-4-[3-(4-chlorophenyl)quinoxalin-2-
yl]furan-2,3-dione (II) in boiling anhydrous p-xylene
(138–139°C) we obtained 4-(4-chlorobenzoyl)-5-(4-
chlorophenyl)-2-[3-(4-chlorophenyl)quinoxalin-2-yl]-
1-oxo-1H-pyrido[1,2-a]quinoxalin-3-yl 4-chloroben-
zoate (III) in almost quantitative yield.
dione II, with generation of aroyl(quinoxalinyl)ketene
IV which undergoes dimerization via [4+2]-cycload-
dition involving imidoylketene fragment of one mole-
cule IV and ketene C=C bond of the other and subse-
quent [1,3]-acylotropic migration of the aroyl group.
The different decarbonylation temperatures of com-
pounds I and II indicate different thermal stabilities of
the dioxopyrrole and dioxofuran rings.
The spectral parameters of compound III were very
similar to those of model 4-benzoyl-5-phenyl-2-(3-
phenylquinoxalin-2-yl)-1-oxo-1H-pyrido[1,2-a]quin-
oxalin-3-yl benzoate whose structure was determined
Compound III is formed as a result of thermal
decarbonylation of pyrroloquinoxalinedione I or furan-
N
Ar
N
Ar
O
COAr
N
N
N
Ar
N
Ar
O
Ar
Δ
[4+2]
O
O
COAr
N
O
I
–CO
Ar
·
N
N
Ar
O
N
O
IV
O
O
Ar
II
Ar
O
N
N
N
[1,3]-COAr
N
ArC(O)O
Ar
O
Ar
III
Ar = 4-ClC6H4.
1261

SILAICHEV, MASLIVETS
1262
1
by X-ray analysis [2]. The H NMR spectra of these
compounds characteristically contained doublets from
the 10-H proton (δ 8.13 and 8.12 ppm, respectively),
which is deshielded due to interaction with the C1=O
carbonyl oxygen atom, and their IR spectra displayed
absorption bands belonging to the ester (1752 and
1745 cm–1) and ketone and lactam carbonyl groups
(broadened bands at 1655 and 1662 cm–1).
nitrile). IR spectrum, ν, cm–1: 1752 (C=O, ester), 1655
1
(C1=O, 4-C=O). H NMR spectrum, δ, ppm: 7.40–
7.95 m (23H, Harom), 8.13 d (1H, 10-H, J = 8.1 Hz).
Found, %: C 65.82; H 2.85; Cl 16.95; N 6.72.
C46H24Cl4N4O4. Calculated, %: C 65.89; H 2.88;
Cl 16.91; N 6.68.
The IR spectrum was recorded on an FSM-1201
1
spectrometer. The H NMR spectrum was run on
a Bruker AM-400 instrument at 400 MHz using
DMSO-d6 as solvent and TMS as internal reference.
4-(4-Chlorobenzoyl)-5-(4-chlorophenyl)-2-[3-(4-
chlorophenyl)quinoxalin-2-yl]-1-oxo-1H-pyrido-
[1,2-a]quinoxalin-3-yl 4-chlorobenzoate (III).
a. A solution of 1.0 mmol of compound I in 5 ml of
anhydrous 1,2,4-trimethylbenzene was heated for
10 min under reflux until violet color typical of the
initial pyrroloquinoxaline disappeared. The mixture
was cooled, and the precipitate was filtered off.
Yield 96%.
This study was performed under financial support
by the Ministry of Education and Science of the
Russian Federation (project no. 2.19.10) and by the
Russian Foundation for Basic Research (project
no. 12-03-00696a).
REFERENCES
b. A solution of 1.0 mmol of compound II in 5 ml
of anhydrous p-xylene was heated for 20 min under
reflux until carbon(II) oxide no longer evolved. The
mixture was cooled, and the precipitate was filtered
off. Yield 95%, mp 304–305°C (decomp., from aceto-
1. Silaichev, P.S., Kryuchkova, M.A., and Maslivets, A.N.,
Russ. J. Org. Chem., 2009, vol. 45, p. 1730.
2. Lisovenko, N.Yu., Krasnykh, O.P., Aliev, Z.G., Vost-
rov, E.S., Tarasova, O.P., and Maslivets, A.N., Khim.
Geterotsikl. Soedin., 2001, p. 1429.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 9 2012