ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 4, p. 607. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © P.S. Silaichev, M.A. Kryuchkova, A.N. Maslivets, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 4, p. 613.
SHORT
COMMUNICATIONS
[4+2]-Cycloaddition of Alkyl Vinyl Ethers
to 3-Aroylpyrrolo[1,2-a]quinoxaline-1,2-dione
P. S. Silaichev, M. A. Kryuchkova, and A. N. Maslivets
Perm State University, ul. Bukireva 15, Perm, 614990 Russia
e-mail: koh2@psu.ru
Received October 27, 2009
DOI: 10.1134/S1070428010040330
Reactions of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2-
diones with activated alkenes were not studied previ-
ously. We examined reactions of 3-(4-chlorobenzoyl)-
4-(4-chlorophenyl)pyrrolo[1,2-a]quinoxaline-1,2-dione
(I) with alkyl vinyl ethers IIa and IIb at a ratio of 1:5
in boiling toluene (20–30 min, until violet color typical
of initial compound I disappeared) and obtained new
difficultly accessible bridged heterocyclic compounds,
16-alkoxy-2,14-bis(4-chlorophenyl)-15-oxa-3,10-di-
azatetracyclo[8.7.0.01,13.04,9]heptadeca-2,4,6,8,13-
pentaene-11,12-diones IIIa and IIIb. Compounds IIIa
and IIIb are likely to be formed via thermal [4+2]-
cycloaddition of the O=C–C3=C3a conjugated bond
system in pyrrolo[1,2-a]quinoxaline-1,2-dione I at the
polarized double C=C bond in vinyl ether IIa or IIb.
crystallized from toluene. Yield 78%, mp 224–225°C.
IR spectrum, ν, cm–1: 1728 (C11=O), 1713 (C12=O).
1H NMR spectrum, δ, ppm: 0.81 t (3H, CH3, J =
7.0 Hz), 2.18 d.d (1H, 17-H, J = 13.4, 4.6 Hz), 2.36 d
(1H, 17-H, J = 13.4 Hz), 3.37 m (1H, OCH2), 3.44 m
(1H, OCH2), 5.62 d (1H, 16-H, J = 4.6 Hz), 7.40–
7.93 m (12H, Harom). Found, %: C 65.75; H 4.38;
N 5.15. C30H24Cl2N2O4. Calculated, %: C 65.82;
H 4.42; N 5.12.
16-Butoxy-2,14-bis(4-chlorophenyl)-15-oxa-3,10-
diazatetracyclo[8.7.0.01,13.04,9]heptadeca-2,4,6,8,13-
pentaene-11,12-dione (IIIb) was synthesized in a sim-
ilar way from butyl vinyl ketone. Yield 74%, mp 219–
220°C (from ethyl acetate). IR spectrum, ν, cm–1: 1726
1
(C11=O), 1714 (C12=O). H NMR spectrum, δ, ppm:
0.72 t (3H, CH3), 0.98 m (2H, CH2), 1.14 m (2H, CH2),
2.18 d.d (1H, 17-H, J = 13.6, 4.4 Hz), 2.35 d (1H,
17-H, J = 13.6 Hz), 3.29 m (1H, OCH2), 3.39 m (1H,
OCH2), 5.60 d (1H, 16-H, J = 4.4 Hz), 7.38–7.90 m
(12H, Harom). Found, %: C 65.75; H 4.38; N 5.15.
C30H24Cl2N2O4. Calculated, %: C 65.82; H 4.42;
N 5.12.
OAlk
N
N
Ar
N
N
Ar
OAlk
H2C
IIa, IIb
O
O
Ar
Ar
O
O
O
O
I
IIIa, IIIb
The IR spectra were measured on a FSM-1201
spectrophotometer from samples dispersed in mineral
oil. The H NMR spectra were recorded on a Bruker
AM-400 spectrometer at 400 MHz using DMSO-d6 as
solvent and tetramethylsilane as internal reference. The
purity of the isolated compounds was checked by TLC
on Silufol plates using benzene–ethyl acetate (5:1) or
ethyl acetate as eluent.
Ar = 4-ClC6H4, Alk = Et (a), Bu (b).
1
2,14-Bis(4-chlorophenyl)-16-ethoxy-15-oxa-3,10-
diazatetracyclo[8.7.0.01,13.04,9]heptadeca-2,4,6,8,13-
pentaene-11,12-dione (IIIa). A solution of 5.0 mmol
of ethyl vinyl ether in 5 ml of anhydrous toluene was
added to a solution of 1.0 mmol of 3-(4-chloroben-
zoyl)-4-(4-chlorophenyl)pyrrolo[1,2-a]quinoxaline-
1,2-dione (I) in 50 ml of anhydrous toluene. The mix-
ture was heated for 20 min under reflux and cooled,
the solvent was removed, and the precipitate was re-
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 08-03-01032).
607
Silaichev
