ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 9, pp. 1401–1402. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.V. Babenysheva, A.N. Maslivets, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 9, pp. 1418–1419.
SHORT
COMMUNICATIONS
Spiro Heterocyclization of Hetareno[a]pyrrole-2,3-diones
in Reactions with N-Alkylanilines
A. V. Babenysheva and A. N. Maslivets
Perm State University, ul. Bukireva 15, Perm, 614990, Russia
e-mail: koh2@psu.ru
Received July 12, 2007
DOI: 10.1134/S1070428008090297
Reactions of hetareno[a]pyrrole-2,3-diones with
N-alkylanilines were not reported previously. We have
found that 3-aroyl-2,4-dihydro-1H-pyrrolo[2,1-c][1,4]-
benzoxazine-1,2,4-triones Ia and Ib react with
N-methyl- and N-ethylanilines IIa and IIb at a ratio of
1:1 on heating in boiling toluene (reaction time 0.5–
2 h) to give substituted 1-alkyl-3′-aroyl-1′-(2-hydroxy-
phenyl)-4′-hydroxyspiro[indole-3,2′-pyrrole]-
2,5′(1H,1′H)-diones IIIa and IIIb.
3,2′-pyrrole] system containing various substituents in
several positions of both heterocyclic fragments.
3′-Benzoyl-1′-(2-hydroxyphenyl)-4′-hydroxy-1-
methylspiro[indole-3,2′-pyrrole]-2,5′(1H,1′H)-dione
(IIIa). A solution of 0.002 mol of compound Ia and
0.002 mol of N-methylaniline (IIa) in 10 ml of anhy-
drous toluene was heated for 2 h under reflux (until it
became colorless). The mixture was cooled, and the
precipitate was filtered off. Yield 77%, mp 268–270°C
(from ethyl acetate). IR spectrum, ν, cm–1: 3244 br
(OH), 1707 (C=O), 1621 (PhC=O). 1H NMR spectrum,
δ, ppm: 3.19 s (3H, CH3N), 6.65–7.72 m (13H, Harom),
Presumably, the process involves initial electro-
philic attack by the C3a atom of pyrrolobenzoxazine-
trione I at the activated ortho-position in aniline II,
followed by closure of indole ring via intramolecular
attack by the secondary amino group on the lactone
carbonyl carbon atom in the 1,4-oxazine ring and
cleavage of the latter at the C4–O5 bond. The trans-
formation sequence is similar to that proposed previ-
ously for the reactions of pyrrolobenzoxazinetriones I
with 3-amino-5,5-dimethylcyclohex-2-en-1-ones,
leading to substituted 3′-aroyl-4′-hydroxy-1′-(o-hy-
droxyphenyl)-6,6-dimethyl-6,7-dihydrospiro[indole-
3,2′-pyrrole]-2,4,5′(1H,1′H,5H)-triones whose struc-
ture was proved by X-ray analysis [1].
13
9.59 s (1H, 2″-OH), 12.48 br.s (1H, 4′-OH). C NMR
spectrum (DMSO-d6), δC, ppm: 26.78 (CH3N), 70.04
(Cspiro), 108.56–153.72 (Carom, C3′, C4′), 165.28 (C5′),
172.92 (C2), 188.53 (COPh). Found, %: C 70.40;
H 4.27; N 6.54. C25H18N2O5. Calculated, %: C 70.42;
H 4.25; N 6.57.
3′-(4-Ethoxybenzoyl)-1-ethyl-1′-(2-hydroxy-
phenyl)-4′-hydroxyspiro[indole-3,2′-pyrrole]-
2,5′(1H,1′H)-dione (IIIb). Yield 85%, mp 265–267°C
(from ethyl acetate). IR spectrum, ν, cm–1: 3237 br
(OH), 1707 (C=O), 1626 (ArC=O). 1H NMR spectrum,
δ, ppm: 1.14 t (3H, CH3CH2N, J = 7.2 Hz), 1.34 t (3H,
CH3CH2O, J = 7.1 Hz), 3.70 q and 3.80 q (1H each,
The described reaction is a rare example of selec-
tive synthesis of difficultly accessible spiro[indole-
Alk
O
N
O
O
OH
N
H
N
O
Δ
Alk
+
COAr
COAr
O
O
OH
IIIa, IIIb
Ia, Ib
IIa, IIb
Ar = Ph (a), 4-EtOC6H4 (b); Alk = Me (a), Et (b).
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Babenysheva
