Five-membered 2,3-dioxo heterocycles: LXX.* spiro heterocyclization of 1H-pyrrole-2,3-diones by the action of 1,5-binucleophiles. Crystalline and molecular structure of ethyl 1'-benzyl-7-methoxy-3,3-dimethyl-1,2'-dioxo-5'- phenyl-1,2,2',3,4,10-hexahydro-1

Article abstract of DOI:10.1134/S1070428010080105

Ethyl 1-alkyl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrole-3-carboxylates reacted with 3-arylamino-5,5-dimethylcyclohex-2-en-1-ones as carbon-centered 1,5-binucleophiles to give the corresponding substituted ethyl 1'-alkyl-3,3-dimethyl-1,2'-dioxo-5'-phenyl-1

Full text of DOI:10.1134/S1070428010080105

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 8, pp. 1173–1177. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © P.S. Silaichev, M.V. Dmitriev, Z.G. Aliev, A.N. Maslivets, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 8,
pp. 1173–1176.
Five-Membered 2,3-Dioxo Heterocycles:
LXX.* Spiro Heterocyclization of 1H-Pyrrole-2,3-diones
by the Action of 1,5-Binucleophiles. Crystalline and Molecular
Structure of Ethyl 1′-Benzyl-7-methoxy-3,3-dimethyl-1,2′-dioxo-
5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-
9,3′-pyrrole]-4′-carboxylate
P. S. Silaicheva, M. V. Dmitrieva, Z. G. Alievb, and A. N. Maslivetsa
a Perm State University, ul. Bukireva 15, Perm, 614990 Russia
e-mail: koh2@psu.ru
b Institute of Chemical Physics Problems, Russian Academy of Sciences,
Chernogolovka, Moscow oblast, Russia
Received June 10, 2009
Abstract—Ethyl 1-alkyl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrole-3-carboxylates reacted with 3-arylamino-
5,5-dimethylcyclohex-2-en-1-ones as carbon-centered 1,5-binucleophiles to give the corresponding substituted
ethyl 1′-alkyl-3,3-dimethyl-1,2′-dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-9,3′-pyrrole]-4′-
carboxylates whose structure was proved by X-ray analysis.
DOI: 10.1134/S1070428010080105
There are a few published data on heterocyclization
of 1H-pyrrole-2,3-diones by the action of binucleo-
philes with participation of the pyrroledione fragment.
Substituted 1H-pyrrole-2,3-diones reacted with o-phen-
ylenediamine to give pyrrolo[2,3-b]quinoxalines as
a result of pyrrole ring fusion at the [b]-side of the
quinoxaline fragment [2]. We previously reported on
[3+3]-nucleophilic addition of cyclic enamines (C,N-
centered 1,3-binucleophiles) to the C5 and C3 atoms in
1H-pyrrole-2,3-diones [3].
By reactions of substituted ethyl 1-alkyl-4,5-dioxo-
2-phenyl-4,5-dihydro-1H-pyrrole-3-carboxylates Ia
and Ib [4] with 3-arylamino-5,5-dimethylcyclohex-2-
en-1-ones IIa–IIg at a molar ratio of 1:1 in boiling an-
hydrous m-xylene (reaction time 5–6 h; TLC monitor-
ing) we obtained in good yields the corresponding
substituted ethyl 1′-alkyl-3,3-dimethyl-1,2′-dioxo-5′-
phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-
9,3′-pyrrole]-4′-carboxylates IIIa–IIIi [5] (Scheme 1)
whose structure was proved by X-ray analysis of com-
pound IIIc.
Compounds IIIa–IIIi were isolated as colorless
crystalline substances that are readily soluble in
DMSO and DMF, poorly soluble in other common
organic solvents, and insoluble in water and saturated
hydrocarbons. The products showed a negative color
test for enolic hydroxy group with an alcoholic solu-
tion of iron(III) chloride. The IR spectra of IIIa–IIIi
contained absorption bands typical of stretching vibra-
tions of NH group (3240–3303 cm–1, broadened band),
lactam and ester carbonyl groups (1682–1694 cm–1),
and ketone carbonyl group (1609–1638 cm–1). Com-
1
pounds IIIa–IIIi displayed in the H NMR spectra
signals from protons in the aliphatic substituents, aro-
matic rings, and substituents in the latter. In addition,
two singlets from protons in two methyl groups
(δ 0.98–1.11 ppm), doublets from four nonequivalent
protons in the C2H2 and C4H2 methylene groups
(δ 2.01–2.69 ppm; J = 16.0–16.6 Hz), and a broadened
singlet from the NH proton (δ 8.44–9.84 ppm) were
present.
The planes of the spiro-fused heterocycles in mole-
cule IIIc are mutually orthogonal. The ethoxycarbonyl
group resides in the pyrrole ring plane, while the
* For communication LXIX, see [1].
1173

SILAICHEV et al.
1174
Scheme 1.
R3
R4
R2
O
O
O
EtO
Ph
HO
O
R4
EtO
NH
+
Me
Me
Ph
O
N
R1
O
N
H
R3
N
R1
R2
Me
Me
O
IV
Ia, Ib
IIa–IIg
R3
R4
R2
EtOCO
NH
–H2O
Ph
O
N
R1
Me
Me
O
IIIa–IIIi
I, R1 = PhCH2 (a), cyclo-C6H11 (b); II, R2 = R3 = H, R4 = H (a), Me (b), MeO (c), Br (d); R2 = R4 = H, R3 = MeO (e); R3 = R4 = H,
R2 = Me (f); R2R3 = benzo, R4 = H (g); III, R1 = PhCH2: R2 = R3 = H, R4 = H (a), Me (b), MeO (c), Br (d); R2 = R4 = H, R3 = MeO (e);
R3 = R4 = H, R2 = Me (f); R2R3 = benzo, R4 = H (g); R1 = cyclo-C6H11: R2 = R4 = H, R3 = MeO (h); R2R3 = benzo, R4 = H (i).
7-methoxy group appears in the acridine ring plane.
The phenyl ring on C5′ with the pyrrole ring plane
forms a dihedral angle of 92.6° (the torsion angle
N1C4C23C24 is 85.1°). Orientation of the benzyl substit-
uent is characterized by the torsion angles C4N1C29C30
94.5° and N1C29C30C31 –147.0° (see figure). All bond
lengths and bond angles in molecule IIIc conform to
the corresponding standard values. Molecules IIIc in
crystal are linked through intermolecular hydrogen
bonds N2–H2···O1 [N2···O1 2.830(4) Å] to give cen-
trosymmetric dimers. No other shortened contacts were
found in the crystalline structure of compound IIIc.
Presumably, compounds IIIa–IIIi are formed via
initial nucleophilic addition of the activated ortho-
carbon atom in the arylamino group of cyclic enamine
IIa–IIg at the carbonyl carbon atom in position 4 of
the pyrrole ring in Ia or Ib. Intermediate IV thus
formed undergoes intramolecular ring closure with
participation of the β-CH group in the enamine frag-
ment. The described reaction is the first example of
direct spiro heterocyclization of substituted 1H-pyr-
role-2,3-dione derivatives by the action of N-aryl-sub-
stituted enamines, the latter acting as carbon-centered
1,5-binucleophiles. This reaction provides a synthetic
route to representatives of difficultly accessible spiro-
[acridine-9,3′-pyrrole] heterocyclic system.
C26
C27
C28
C25
C24
C22
C23
C4
C3
C32
C31
C29
C30
O3 C21
C33
O4
C16
N1
C2
C20
O2
C35
O5
C34
C15
O1
C1
C6
C5
C7
C18
C12
C14
C13
C8
C11
C17
C19
N2
C10
C9
EXPERIMENTAL
Structure of the molecule of ethyl 1′-benzyl-7-methoxy-3,3-
dimethyl-1,2′-dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-
spiro[acridine-9,3′-pyrrole]-4′-carboxylate (IIIc) according
to the X-ray diffraction data.
The IR spectra were recorded on an FSM-1201
1
spectrometer. The H and 13C NMR spectra were
measured on a Bruker AM-400 instrument at 400 and
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

FIVE-MEMBERED 2,3-DIOXO HETEROCYCLES: LXX.
1175
3264 br (NH), 1687 (COO, C2′=O), 1624 (C1=O).
1H NMR spectrum, δ, ppm: 0.74 t (3H, CH2CH3, J =
7.2 Hz), 0.99 s (3H, Me), 1.08 s (3H, Me), 2.06 d (1H,
4-H, J = 16.0 Hz), 2.12 s (3H, Me), 2.20 d (1H, 4-H,
J = 16.0 Hz), 2.30 d and 2.55 d (1H each, 2-H, J =
16.4 Hz), 3.59 m (2H, OCH2), 4.38 d and 4.66 d (1H
each, CH2Ph, J = 16.0 Hz), 6.59 s (1H, 8-H), 6.82 d
(1H, 5-H, J = 8.4 Hz), 6.95 d (1H, 6-H, J = 8.4 Hz),
7.06–7.45 m (10H, Ph), 9.62 br.s (1H, NH). 13C NMR
spectrum, δC, ppm: 13.22 (CH3CH2), 20.32 (7-CH3),
26.25 (Me), 28.89 (Me), 31.89 (C3), 40.72 (C4), 43.77
(C9), 50.07 (CH2Ph), 51.78 (C2), 58.35 (CH3CH2),
103.16–153.09 (Carom, C2′, C9a, C4′, C5′), 161.93 (COO),
181.41 (C4a), 191.59 (C1). Found, %: C 76.75; H 6.39;
N 5.03. C35H34N2O4. Calculated, %: C 76.90; H 6.27;
N 5.12.
100 MHz, respectively, 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.
Ethyl 1-cyclohexyl-4,5-dioxo-2-phenyl-4,5-dihy-
dro-1H-pyrrole-3-carboxylate (Ib). A solution of
0.1 mol of ethyl 3-oxo-3-phenylbutanoate, 0.5 mol of
cyclohexylamine, and 0.5 mol of acetic acid in 100 ml
of anhydrous ethanol was heated for 2 h under reflux.
The solvent was removed under reduced pressure, the
residue was dissolved in 100 ml of benzene, the solu-
tion was washed with 5% hydrochloric acid (2×20 ml)
and water (3×100 ml) and dried over magnesium sul-
fate, the solvent was removed under reduced pressure,
and the oily residue, ethyl 3-phenyl-3-cyclohexyl-
aminoacrylate, was dissolved without additional puri-
fication in 50 ml of chloroform. Oxalyl chloride,
0.08 mol, was added to the resulting solution, the mix-
ture was heated for 2 h under reflux, cooled, and
diluted with 50 ml of hexane, and the precipitate was
filtered off. Yield 66%, mp 145–148°C (from chloro-
form–hexane, 1 : 1). IR spectrum, ν, cm–1: 1773
Ethyl 1′-benzyl-7-methoxy-3,3-dimethyl-1,2′-
dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro-
[acridine-9,3′-pyrrole]-4′-carboxylate (IIIc). Yield
78%, mp 268–269°C (from toluene). IR spectrum, ν,
cm–1: 3256 br (NH), 1687 (COO, C2′=O), 1626
1
(C1=O). H NMR spectrum, δ, ppm: 0.74 t (3H,
CH2CH3, J = 6.8 Hz), 0.99 s (3H, Me), 1.08 s (3H,
Me), 2.06 d and 2.20 d (1H each, 4-H, J = 16.4 Hz),
2.30 d and 2.55 d (1H each, 2-H, J = 16.6 Hz), 3.56 s
(3H, OMe), 3.60 m (2H, OCH2), 4.36 d and 4.65 d
(1H each, CH2Ph, J = 15.6 Hz), 6.33 s (1H, 8-H),
6.78 d (1H, 6-H, J = 8.8 Hz), 6.89 d (1H, 5-H, J =
8.8 Hz), 7.06–7.46 m (10H, Ph), 9.63 br.s (1H, NH).
13C NMR spectrum, δC, ppm: 13.23 (CH3CH2), 26.26
(Me), 28.89 (Me), 31.90 (C3), 40.72 (C4), 43.82 (C9),
50.08 (CH2Ph), 52.20 (C2), 54.88 (OMe), 58.37
(OCH2), 102.22–155.10 (Carom, C2′, C9a, C4′, C5′),
161.86 (COO), 181.29 (C4a), 191.46 (C1). Found, %:
C 74.80; H 6.03; N 5.00. C35H34N2O5. Calculated, %:
C 74.71; H 6.09; N 4.98.
1
(C5=O), 1719 (COO), 1703 (C4=O). H NMR spec-
trum, δ, ppm: 0.90 t (3H, CH2CH3, J = 7.2 Hz), 0.77–
1.99 m (10H, CH2), 3.13 m (1H, NCH), 3.88 m (2H,
OCH2), 7.25–7.62 m (5H, Ph).
Ethyl 1′-benzyl-3,3-dimethyl-1,2′-dioxo-5′-
phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-
9,3′-pyrrole]-4′-carboxylate (IIIa). A solution of
1.0 mmol of compound Ia and 1.0 mmol of enamine
IIa in 15 ml of anhydrous m-xylene was heated for 5 h
under reflux. The mixture was cooled, and the precip-
itate was filtered off. Yield 76%, mp 227–228°C (from
toluene). IR spectrum, ν, cm–1: 3240 br (NH), 1682
1
(COO, C2′=O), 1621 (C1=O). H NMR spectrum, δ,
Ethyl 1′-benzyl-7-bromo-3,3-dimethyl-1,2′-
dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro-
[acridine-9,3′-pyrrole]-4′-carboxylate (IIId). Yield
75%, mp 279–280°C (from toluene). IR spectrum, ν,
cm–1: 3270 br (NH), 1690 (COO, C2′=O), 1621
ppm: 0.73 t (3H, CH2CH3, J = 7.2 Hz), 1.00 s (3H,
Me), 1.09 s (3H, Me), 2.09 d and 2.22 d (1H each, 4-H,
J = 16.0 Hz), 2.33 d and 2.57 d (1H each, 2-H, J =
16.4 Hz), 3.59 m (2H, OCH2), 4.49 d and 4.54 d (1H
each, CH2Ph, J = 15.6 Hz), 6.88–7.43 m (14H, Harom),
9.69 br.s (1H, NH). Found, %: C 76.61; H 6.08; N 5.23.
C34H32N2O4. Calculated, %: C 76.67; H 6.06; N 5.26.
1
(C1=O). H NMR spectrum, δ, ppm: 0.75 t (3H,
CH2CH3, J = 7.2 Hz), 0.98 s (3H, Me), 1.08 s (3H,
Me), 2.08 d and 2.22 d (1H each, 4-H, J = 16.0 Hz),
2.31 d and 2.58 d (1H each, 2-H, J = 16.4 Hz), 3.62 m
(2H, OCH2), 4.39 d and 4.68 d (1H each, CH2Ph,
J = 15.6 Hz), 6.89–7.48 m (13H, Harom), 9.84 br.s
(1H, NH). Found, %: C 66.74; H 5.08; N 4.54.
C34H31BrN2O4. Calculated, %: C 66.78; H 5.11; N 4.58.
Compounds IIIb–IIIi were synthesized in a similar
way.
Ethyl 1′-benzyl-3,3,7-trimethyl-1,2′-dioxo-5′-
phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-
9,3′-pyrrole]-4′-carboxylate (IIIb). Yield 73%,
mp 263–264°C (from toluene). IR spectrum, ν, cm–1:
Ethyl 1′-benzyl-6-methoxy-3,3-dimethyl-1,2′-
dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 8 2010

SILAICHEV et al.
1176
16.3 Hz), 3.11 m (1H, NCH), 3.55 m (2H, OCH2), 3.71 s
(3H, OMe), 6.42–7.62 m (8H, Harom), 9.52 br.s (1H,
NH). Found, %: C 73.69; H 6.94; N 4.92. C34H38N2O5.
Calculated, %: C 73.62; H 6.91; N 5.05.
[acridine-9,3′-pyrrole]-4′-carboxylate (IIIe). Yield
81%, mp 257–258°C (from toluene). IR spectrum, ν,
cm–1: 3270 br (NH), 1690 (COO, C2′=O), 1611
1
(C1=O). H NMR spectrum, δ, ppm: 0.74 t (3H,
CH2CH3, J = 7.2 Hz), 1.00 s (3H, Me), 1.08 s (3H,
Me), 2.05 d and 2.21 d (1H each, 4-H, J = 16.4 Hz),
2.30 d and 2.55 d (1H each, 2-H, J = 16.4 Hz), 3.59 m
(2H, OCH2), 3.72 s (3H, OMe), 4.47 d and 4.53 d (1H
each, CH2Ph, J = 15.6 Hz), 6.46–7.42 m (13H, Harom),
9.63 br.s (1H, NH). Found, %: C 74.65; H 6.01; N 4.92.
C35H34N2O5. Calculated, %: C 74.71; H 6.09; N 4.98.
Ethyl 1′-benzyl-3,3,5-trimethyl-1,2′-dioxo-5′-
phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro[acridine-
9,3′-pyrrole]-4′-carboxylate (IIIf). Yield 70%,
mp 281–282°C (from toluene). IR spectrum, ν, cm–1:
3260 br (NH), 1687 (COO, C2′=O), 1638 (C1=O).
1H NMR spectrum, δ, ppm: 0.73 t (3H, CH2CH3, J =
7.2 Hz), 1.00 s (3H, Me), 1.09 s (3H, Me), 2.09 d and
2.22 d (1H each, 4-H, J = 16.0 Hz), 2.30 s (3H, Me),
2.61 s (2H, 2-H), 3.59 m (2H, OCH2), 4.47 d and
4.54 d (1H each, CH2Ph, J = 16.0 Hz), 6.74–7.43 m
(13H, Harom), 8.44 br.s (1H, NH). 13C NMR spectrum,
δC, ppm: 13.24 (CH3CH2), 17.61 (5-Me), 26.29 (Me),
28.91 (Me), 31.89 (C3), 40.68 (C4), 43.99 (C9), 52.05
(C2), 58.31 (OCH2), 104.24–153.56 (Carom, C2′, C9a, C4′,
C5′), 161.93 (COO), 181.59 (C4a), 192.29 (C1) Found,
%: C 76.94; H 6.25; N 5.09. C33H34N2O5. Calculated,
%: C 76.90; H 6.27; N 5.12.
Ethyl 1′-cyclohexyl-10,10-dimethyl-2′,8-dioxo-5′-
phenyl-1′,2′,9,10,11,12-hexahydro-8H-spiro[benzo-
[c]acridine-7,3′-pyrrole]-4′-carboxylate (IIIi). Yield
78%, mp 313–315°C (from toluene). IR spectrum, ν,
cm–1: 3303 br (NH), 1690 (COO, C2′=O), 1617 (C1=O).
1H NMR spectrum, δ, ppm: 0.63 t (3H, CH2CH3, J =
7.1 Hz), 0.85–2.08 m (10H, CH2), 1.03 s (3H, Me),
1.11 s (3H, Me), 2.08 d and 2.23 d (1H each, 11-H, J =
16.0 Hz), 2.64 d and 2.69 d (1H each, 9-H, J =
16.8 Hz), 3.17 m (1H, NCH), 3.50 m (2H, OCH2),
7.01–8.48 m (11H, Harom), 9.29 br.s (1H, NH). Found,
%: C 7.45; H 6.61; N 4.79. C37H38N2O4. Calculated,
%: C 77.33; H 6.66; N 4.87.
X-Ray diffraction data for compound IIIc.
Colorless well-defined crystals, C35H34N2O5; mono-
clinic crystal system, space group P21/c; unit cell pa-
rameters: a = 12.385(2), b = 9.662(2), c = 24.998(4) Å;
β = 99.72(1)°; V = 2948.4(9) Å3; M 562.64; dcalc
=
1.268 g/cm3; Z = 4. Experimental reflection intensities
were measured on a KM-4 (KUMA Diffraction) auto-
matic four-circle diffractometer with χ-geometry
[monochromatized MoKα irradiation, ω/2Θ scanning,
2Θmax = 50.0° (85.7%)]. Total of 5895 reflections were
measured, 4461 of which were independent (Rint
=
Ethyl 1′-benzyl-10,10-dimethyl-2′,8-dioxo-5′-
phenyl-1′,2′,9,10,11,12-hexahydro-8H-spiro[benzo-
[c]acridine-7,3′-pyrrole]-4′-carboxylate (IIIg). Yield
74%, mp 304–305°C (from toluene). IR spectrum, ν,
cm–1: 3280 br (NH), 1688 (COO, C2′=O), 1622 (C1=O).
1H NMR spectrum, δ, ppm: 0.65 t (3H, CH2CH3, J =
7.2 Hz), 1.05 s (3H, Me), 1.13 s (3H, Me), 2.15 d and
2.28 d (1H each, 11-H, J = 16.0 Hz), 2.69 d and 2.73 d
(1H each, 9-H, J = 16.8 Hz), 3.54 m (2H, OCH2),
4.53 d and 4.60 d (1H each, CH2Ph, J = 15.6 Hz),
6.98–8.50 m (16H, Harom), 9.40 br.s (1H, NH). Found,
%: C 78.37; H 5.84; N 4.77. C38H34N2O4. Calculated,
%: C 78.33; H 5.88; N 4.81.
0.0411). No correction for absorption was introduced
(μ = 0.085 mm–1). The structure was solved by the
direct method using SIR92 program [6], followed by
a series of calculations of electron density maps.
Hydrogen atoms were placed into positions calculated
on the basis of geometry considerations, and their
positions were refined according to the riding model.
The positions of non-hydrogen atoms were refined by
the least-squares procedure in full-matrix anisotropic
approximation using SHELXL-97 software [7, 8]. The
final divergence factors were R1 = 0.0582, wR2 =
0.0974 [for 1649 reflections with I ≥ 2σ(I)]; number of
refined parameters 379; goodness of fit 0.893.
Ethyl 1′-cyclohexyl-6-methoxy-3,3-dimethyl-1,2′-
dioxo-5′-phenyl-1′,2,2′,3,4,10-hexahydro-1H-spiro-
[acridine-9,3′-pyrrole]-4′-carboxylate (IIIh). Yield
73%, mp 233–235°C (from toluene). IR spectrum, ν,
cm–1: 3268 br (NH), 1694 (COO, C2′=O), 1609 (C1=O).
1H NMR spectrum, δ, ppm: 0.72 t (3H, CH2CH3, J =
7.1 Hz), 0.84–2.07 m (10H, CH2), 0.98 s (3H, Me),
1.06 s (3H, Me), 2.01 d and 2.16 d (1H each, 4-H, J =
16.3 Hz), 2.26 d and 2.50 d (1H each, 2-H, J =
This study was performed under financial support
by the Russian Foundation for Basic Research (project
nos. 07-03-96036, 08-03-01032).
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