Five-membered 2,3-dioxo heterocycles: LXXVII. [4 + 2]-cycloaddition of alkyl vinyl ethers to 3-aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4(4H)-triones

Article abstract of DOI:10.1134/S1070428011060182

[4 + 2]-Cycloaddition of 3-aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4(4H)- triones to alkyl vinyl ethers gave substituted stereoisomeric (1R,16R)- and (1S,16R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetracyclo[ 8.7.0.0 ^1,13.0^4,9]heptadec

Full text of DOI:10.1134/S1070428011060182

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 6, pp. 937–940. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © E.E. Stepanova, A.V. Babenysheva, A.N. Maslivets, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 6,
pp. 919–922.
Five-Membered 2,3-Dioxo Heterocycles:
LXXVII.* [4+2]-Cycloaddition of Alkyl Vinyl Ethers
to 3-Aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4(4H)-triones
E. E. Stepanova, A. V. Babenysheva, and A. N. Maslivets
Perm State University, ul. Bukireva 15, Perm, 614990 Russia
e-mail: koh2@psu.ru
Received October 7, 2010
Abstract—[4+2]-Cycloaddition of 3-aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4(4H)-triones to alkyl vinyl
ethers gave substituted stereoisomeric (1R*,16R*)- and (1S*,16R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetra-
cyclo[8.7.0.01,13.04,9]heptadeca-4,6,8,13-tetraene-2,11,12-triones.
DOI: 10.1134/S1070428011060182
Cycloaddition at conjugated multiple bonds in
4-acyl-2,3-dihydro-1H-pyrrole-2,3-diones fused to
an isoquinoline fragment was extensively studied with
a view to develop a strategy for building up heterocy-
clic system typical of Erythrina alkaloids [2, 3]. Ther-
mal [4+2]-cycloaddition of polar C=C dienophiles at
the conjugated C5=C4–C=O bond system of mono-
cyclic 4-aroyl-substituted 1H-pyrrole-2,3-diones was
reported to produce pyrano[4,3-b]pyrrole heterocyclic
system [3–5]. Cycloaddition of olefins to 1H-pyrrole-
2,3-diones fused to a 1,4-benzoxazin-2-one fragment,
i.e., pyrrolo[2,1-c][1,4]benzoxazine-1,2,4(4H)-triones,
was not studied previously.
We examined reactions of 3-aroylpyrrolo[2,1-c]-
[1,4]benzoxazine-1,2,4(4H)-triones Ia–If with alkyl
vinyl ethers IIa and IIb. Compounds Ia–Id were re-
ported previously [6], while pyrrolobenzoxazinetriones
Ie and If were synthesized for the first time by treat-
ment of (3Z)-3-(-2-aryl-2-oxoethylidene)-3,4-dihydro-
2H-benzo[b][1,4]oxazin-2-ones IIIa and IIIb with
oxalyl chloride. Compounds IIIa and IIIb were pre-
pared in turn by reaction of 4-aryl-2,4-dioxobutanoic
acids IVa and IVb with 2-aminophenols Va and Vb.
The Z configuration of the exocyclic double bond in
IIIa and IIIb is typical of such compounds; it followed
from their spectral parameters [7].
rolobenzoxazinetriones I disappeared) we obtained
representatives of a new class of difficultly accessible
fused heterocyclic compounds, stereoisomeric
(1R*,16R*)- and (1S*,16R*)-16-alkoxy-14-aryl-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-triones VIa–VIh [8] and
VIIa–VIIh. Stereoisomers VIa–VIh were formed as
major products, while minor stereoisomers VIIa–VIIh
were not generally isolated; the latter gave rise to
1
minor set of signals in the H NMR spectra. Only in
one case we succeeded in isolating by fractional crys-
tallization pure diastereoisomers VIh and VIIh.
Stereoisomer mixtures VIa/VIIa–VIh/VIIh are
yellow high-melting crystalline substances, which melt
with decomposition and are readily soluble in DMSO
and DMF, poorly soluble in other common organic
solvents, and insoluble in saturated hydrocarbons and
water. Isomers VIIa–VIIh are considerably better
soluble in organic solvents and are characterized by
higher Rf values than their isomers VIa–VIh.
The IR spectra of VI/VII contained absorption
bands due to stretching vibrations of lactone carbonyl
group (C2=O, 1771–1802 cm–1), lactam carbonyl group
(C11=O) and ketone carbonyl group (C12=O, 1715–
1731 cm–1). Compounds VIa–VIh displayed in the
1H NMR spectra signals from protons in aliphatic
substituents and aromatic rings, as well as multiplet
signals from the equatorial 16-H proton and methylene
protons on C17 which give rise to an ABX spin system
(δ 5.73–5.84 and 2.37–2.44 ppm, respectively). The
By heating compounds Ia–If with alkyl vinyl ethers
IIa and IIb at a ratio of 1:5 in boiling benzene (reac-
tion time 20–60 min; until violet color of initial pyr-
* For communication LXXVI, see [1].
937

STEPANOVA et al.
938
Scheme 1.
O
O
O
O
R
NH2
OH
+
R
N
H
Ar
OH
O
O
Ar
IVa, IVb
Va, Vb
IIIa, IIIb
OAlk
AlkO
O
5
O
O
O
O
O
N
16
O15
6
7
3
2
1
4
9
17
O
O
10
N
(COCl)2
AlkOCH=CH2 (IIa, IIb)
14
R
N
R
R
+
13
8
11
12
Ar
Ar
Ar
O
O
O
O
O
O
Ia–If
VIa–VIh
VIIa–VIIh
I, Ar = Ph (a, f), 4-EtOC6H4 (b), 4-MeOC6H4 (c), 4-BrC6H4 (d), 4-O2NC6H4 (e); R = H (a–e), Cl (f); II, Alk = Et (a), Bu (b);
III, Ar = 4-O2NC6H4 (a), Ph (b); R = H (a), Cl (b); IV, Ar = 4-O2NC6H4 (a), Ph (b); V, R = H (a), Cl (b); VI, VII, Alk = Et (a, d–h),
Bu (b, c); Ar = Ph (a, b, h), 4-EtOC6H4 (c, f), 4-O2NC6H4 (d), 4-MeOC6H4 (e), 4-BrC6H4 (g); R = H (a–g), Cl (h).
the orange precipitate was filtered off. Yield 89%,
mp 245–247°C (from 1,4-dioxane). IR spectrum, ν,
cm–1: 3069 br (NH), 1758 (C2=O), 1622 (C2′=O).
1H NMR spectrum, δ, ppm: 6.92 s (1H, CH), 7.17–
8.37 m (8H, Harom), 12.93 s (1H, NH). Found, %:
C 61.82; H 3.21; N 9.15. C16H10N2O5. Calculated, %:
C 61.94; H 3.25; N 9.03.
16-H and 17-H signals of minor isomers VIIa–VIIh
were located at δ 5.56–5.64 (16-Hax), 2.13–2.26
(17-Hax), and 2.61–2.79 ppm (17-Heq) (ABX). The
intensity ratio of signals from major isomers VI and
minor isomers VII in the H NMR spectra of the
reaction mixtures was ~5:1.
1
Presumably, compounds VIa–VIh and VIIa–VIIh
are formed as a result of participation of the
O=C–C3=C3a conjugated bond system in 3-aroylpyr-
rolo[2,1-c][1,4]benzoxazine-1,2,4(4H)-triones Ia–If in
thermally initiated [4+2]-cycloaddition to the polar-
ized C=C bond in alkyl vinyl ethers IIa and IIb.
Predominant formation of stereoisomers VIa–VIh
suggests that pseudoaxial orientation of the alkoxy
group in the transition state for cycloaddition is more
favorable.
(3Z)-6-Chloro-3-(2-oxo-2-phenylethylidene)-
3,4-dihydro-2H-1,4-benzoxazin-2-one (IIIb) was
synthesized in a similar way. Yield 85%, mp 218–
220°C (from toluene). IR spectrum, ν, cm–1: 3071 br
(NH), 1765 (C2=O), 1622 (C2′=O). 1H NMR spectrum,
δ, ppm: 6.93 s (1H, CH), 7.13–8.05 m (8H, Harom),
12.62 s (1H, NH). Found, %: C 64.22; H 3.41;
Cl 11.81; N 4.55. C16H10ClNO3. Calculated, %:
C 64.12; H 3.36; Cl 11.83; N 4.67.
3-(4-Nitrobenzoyl)pyrrolo[2,1-c][1,4]benzoxa-
zine-1,2,4(4H)-trione (Ie). A mixture of 1.0 mmol of
compound IIIa and 1.1 mmol of oxalyl chloride in
70 ml of anhydrous benzene was heated for 110 min
under reflux. The mixture was cooled, and the violet
precipitate was filtered off. Yield 93%, mp 193–195°C.
IR spectrum, ν, cm–1: 1777 (C4=O), 1737 (C1=O,
C2=O), 1656 (C1′=O). 1H NMR spectrum, δ, ppm: 7.31–
8.40 m (8H, Harom). Found, %: C 59.42; H 2.28; N 7.53.
C18H8N2O7. Calculated, %: C 59.35; H 2.21; N 7.69.
EXPERIMENTAL
The IR spectra were recorded on an FSM-1201
1
spectrometer. The H and 13C NMR spectra were
measured on a Bruker AM-400 spectrometer at 400
and 100 MHz, respectively, using DMSO-d6 as solvent
and tetramethylsilane as internal reference. The purity
of the synthesized compounds was checked by TLC on
Silufol plates using benzene–ethyl acetate (5:1) and
benzene as eluents.
3-Benzoyl-8-chloropyrrolo[2,1-c][1,4]benzoxa-
zine-1,2,4(4H)-trione (If) was synthesized in a similar
way. Yield 92%, mp 209–211°C. IR spectrum, ν, cm–1:
1780 (C4=O), 1738 (C1=O, C2=O), 1655 (C1′=O).
1H NMR spectrum, δ, ppm: 6.94–8.32 m (8H, Harom).
Found, %: C 61.23; H 2.38; Cl 10.06; N 3.89.
(3Z)-[-2-(4-Nitrophenyl)-2-oxoethylidene]-3,4-di-
hydro-2H-1,4-benzoxazin-2-one (IIIa). A mixture of
1.0 mmol of 4-(4-nitrophenyl)-2,4-dioxobutanoic acid
and 1.0 mmol of 2-aminophenol in 50 ml of propan-
2-ol was heated for 90 min under reflux. After cooling,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 6 2011

FIVE-MEMBERED 2,3-DIOXO HETEROCYCLES: LXXVII.
939
C18H8ClNO5. Calculated, %: C 61.12; H 2.28; Cl 10.02;
N 3.96.
Found, %: C 68.75; H 5.11; N 3.22. C24H21NO6. Cal-
culated, %: C 68.73; H 5.05; N 3.34.
(1R*,16R*)-16-Ethoxy-14-phenyl-3,15-dioxa-10-
azatetracyclo[8.7.0.01,13.04,9]heptadeca-4,6,8,13-
tetraene-2,11,12-trione (VIa) and (1S*,16R*)-16-
ethoxy-14-phenyl-3,15-dioxa-10-azatetracyclo-
[8.7.0.01,13.04,9]heptadeca-4,6,8,13-tetraene-2,11,12-
trione (VIIa) (mixture of diastereoisomers at a ratio of
~10:3). A solution of 5.0 mmol of ethyl vinyl ether in
5 ml of anhydrous benzene was added to a solution of
1.0 mmol of compound Ia in 50 ml of anhydrous ben-
zene. The mixture was heated for 40 min (until violet
color typical of initial compound Ia disappeared) and
cooled, and the precipitate was filtered off. Yield 89%,
mp 236–239°C (decomp.). IR spectrum, ν, cm–1: 1786
(1R*,16R*)-16-Butoxy-14-(4-ethoxyphenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]-heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIc) and
(1S*,16R*)-16-butoxy-14-(4-ethoxyphenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIIc) (mixture of
diastereoisomers at a ratio of ~10:1). Yield 88%,
mp 186–188°C (decomp.). IR spectrum, ν, cm–1: 1798
1
(C2=O), 1728 (C11=O, C12=O). H NMR spectrum, δ,
ppm: VIc: 0.83 t (3H, CH3, J = 7.4 Hz), 1.29 m (2H,
CH2CH3), 1.39 t (3H, OCH2CH3, J = 7.0 Hz), 1.47 m
(2H, CH2CH2CH3), 2.38 m (2H, 17-H), 3.64 m and
3.79 m (2H, OCH2), 4.17 m (2H, OCH2CH3), 5.73 m
(1H, CH), 6.90–8.00 m (8H, Harom); VIIc: 0.89 t (3H,
CH3, J = 7.2 Hz), 1.37 m (2H, CH2CH3), 1.39 t (3H,
OCH2CH3, J = 7.0 Hz), 1.57 m (2H, CH2CH2CH3),
2.19 m (1H, 17-H, J = 9.8, 13.0 Hz), 2.79 m (1H,
17-H, J = 4.2, 12.8 Hz), 3.66 m and 4.01 m (2H,
OCH2), 4.17 m (2H, OCH2CH3), 5.56 m (1H, CH, J =
4.0, 10.2 Hz), 6.90–7.88 m (8H, Harom). Found, %:
C 67.46; H 5.47; N 3.11. C26H25NO7. Calculated, %:
C 67.38; H 5.44; N 3.02.
1
(C2=O), 1724 (C11=O, C12=O). H NMR spectrum, δ,
ppm: VIa: 1.11 t (3H, CH3, J = 7.0 Hz), 2.39 m (2H,
17-H), 3.72 m and 3.82 m (2H, OCH2), 5.79 m (1H,
CH), 7.34–7.95 m (9H, Harom); VIIa: 1.21 t (3H, CH3,
J = 7.2 Hz), 2.19 m (1H, 17-H, J = 10.4, 12.8 Hz),
2.62 m (1H, 17-H, J = 4.2, 13.0 Hz), 3.82 m and
4.04 m (2H, OCH2), 5.60 m (1H, CH, J = 4.0,
10.4 Hz), 7.34–7.85 m (9H, Harom). 13C NMR spec-
trum, δC, ppm: VIa: 14.67 (Me), 38.88 (C17), 54.48
(OCH2), 65.65 (C1), 100.33 (C16), 102.86 (C13), 116.68–
143.10 (Carom), 159.17 (C11), 160.77 (C2), 166.92 (C14),
175.96 (C12). Found, %: C 67.48; H 4.44; N 3.55.
C22H17NO6. Calculated, %: C 67.51; H 4.38; N 3.58.
(1R*,16R*)-16-Ethoxy-14-(4-nitrophenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VId) and
(1S*,16R*)-16-ethoxy-14-(4-nitrophenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIId) (mixture of
diastereoisomers at a ratio of ~5:3). Yield 87%,
mp 236–240°C (decomp.). IR spectrum, ν, cm–1: 1802
Compounds VIb–VIg and VIIb–VIIg were synthe-
sized in a similar way.
(1R*,16R*)-16-Butoxy-14-phenyl-3,15-dioxa-10-
azatetracyclo[8.7.0.01,13.04,9]heptadeca-4,6,8,13-
tetraene-2,11,12-trione (VIb) and (1S*,16R*)-
16-butoxy-14-phenyl-3,15-dioxa-10-azatetracyclo-
[8.7.0.01,13.04,9]heptadeca-4,6,8,13-tetraene-2,11,12-
trione (VIIb) (mixture of diastereoisomers at a ratio of
~10:1). Yield 91%, mp 203–204°C (decomp.). IR spec-
trum, ν, cm–1: 1788 (C2=O), 1725 (C11=O, C12=O).
1H NMR spectrum, δ, ppm: VIb: 0.83 t (3H, CH3, J =
7.3 Hz), 1.29 m (2H, CH2Me), 1.46 m (2H, CH2Et),
2.40 t (2H, 17-H, J = 3.2 Hz), 3.67 m and 3.78 m (2H,
OCH2), 5.77 m (1H, CH), 7.33–7.93 m (9H, Harom);
VIIb: 0.89 t (3H, CH3, J = 7.2 Hz), 1.37 m (2H,
CH2Me), 1.57 m (2H, CH2Et), 2.18 m (1H, 17-H, J =
9.4, 12.6 Hz), 2.62 m (1H, 17-H, J = 4.4, 12.8 Hz),
3.80 m and 4.01 m (2H, OCH2), 5.60 m (1H, CH, J =
1
(C2=O), 1731 (C11=O, C12=O). H NMR spectrum, δ,
ppm: VId: 1.11 t (3H, CH3, J = 7.0 Hz), 2.42 m (2H,
17-H), 3.72 m and 3.82 m (2H, OCH2), 5.84 m (1H,
CH), 6.95–8.43 m (8H, Harom); VIId: 1.21 t (3H, CH3,
J = 7.2 Hz), 2.26 m (1H, 17-H, J = 10.0, 13.2 Hz),
2.62 m (1H, 17-H, J = 3.8, 12.6 Hz), 3.81 m and
4.05 m (2H, OCH2), 5.64 m (1H, CH, J = 4.0,
10.4 Hz), 6.95–8.34 m (8H, Harom). Found, %: C 60.58;
H 3.64; N 6.55. C22H16N2O8. Calculated, %: C 60.55;
H 3.70; N 6.42.
(1R*,16R*)-16-Ethoxy-14-(4-methoxyphenyl)-
3,15-dioxa-10-azatetracyclo[8.7.0.01,13.04,9]hepta-
deca-4,6,8,13-tetraene-2,11,12-trione (VIe) and
(1S*,16R*)-16-ethoxy-14-(4-methoxyphenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIIe) (mixture of
diastereoisomers at a ratio of ~5:1). Yield 93%,
mp 234–236°C (decomp.). IR spectrum, ν, cm–1: 1771
13
4, 10.4 Hz), 7.33–7.85 m (9H, Harom). C NMR spec-
trum, δC, ppm: VIb: 13.57 (Me), 18.37 (CH2Me),
30.92 (CH2CH2Me), 38.88 (C17), 54.46 (OCH2), 69.05
(C1), 100.67 (C16), 102.81 (C13), 116.68–143.13 (Carom),
159.17 (C11), 160.72 (C2), 166.54 (C14), 175.91 (C12).
1
(C2=O), 1715 (C11=O, C12=O). H NMR spectrum, δ,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 6 2011

STEPANOVA et al.
940
ppm: VIe: 1.11 t (3H, CH2CH3, J = 7.0 Hz), 2.37 m
(2H, 17-H), 3.71 m and 3.81 m (2H, OCH2), 3.90 s
(3H, OCH3), 5.75 m (1H, CH), 7.11–8.00 m (8H,
(16S*,1R*)-7-chloro-16-ethoxy-14-phenyl-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIIh). A solution of
5.0 mmol of ethyl vinyl ether in 5 ml of anhydrous
benzene was added to a solution of 1.0 mmol of
compound If in 50 ml of anhydrous benzene, and the
mixture was heated for 20 min under reflux until violet
color typical of initial compound If disappeared. The
mixture was cooled, and the precipitate of stereoisomer
VIh was filtered off. Yield 79%, mp 243–245°C
(decomp.). IR spectrum, ν, cm–1: 1788 (C2=O), 1724
Harom); VIIe: 1.21 t (3H, Me, J = 7.0 Hz), 2.14 m (1H,
17-H, J = 10.4, 12.8 Hz), 2.61 m (1H, 17-H, J = 4.4,
13.2 Hz), 3.80 m and 4.06 m (2H, OCH2), 3.90 s (3H,
OCH3), 5.58 m (1H, CH, J = 4.4, 10.4 Hz), 7.11–
7.90 m (8H, Harom). Found, %: C 65.59; H 4.57; N 3.35.
C23H19NO7. Calculated, %: C 65.55; H 4.54; N 3.32.
(1R*,16R*)-16-Ethoxy-14-(4-ethoxyphenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIf) and
(1S*,16R*)-16-ethoxy-14-(4-ethoxyphenyl)-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIIf) (mixture of
diastereoisomers at a ratio of ~10:1). Yield 91%,
mp 202–204°C (decomp.). IR spectrum, ν, cm–1: 1794
1
(C11=O, C12=O). H NMR spectrum, δ, ppm: 1.11 t
(3H, CH3, J = 7.0 Hz), 2.44 m (2H, 17-H), 3.72 m and
3.82 m (2H, OCH2), 5.80 m (1H, CH), 7.37–7.90 m
(7H, Harom). Found, %: C 62.21; H 3.80; Cl 8.21;
N 3.25. C22H16ClNO6. Calculated, %: C 62.05; H 3.79;
N 3.29; Cl 8.33. The mother liquor was evaporated to
dryness, the residue was ground with 10 ml of hexane,
and the precipitate of stereoisomer VIIh was filtered
off. Yield 12%, mp 237–239°C (decomp.). IR spec-
trum, ν, cm–1: 1777 (C2=O), 1730 (C11=O, C12=O).
1H NMR spectrum, δ, ppm: 1.22 t (3H, CH3, J =
7.0 Hz), 2.19 m (1H, 17-H, J = 4.2, 13.0 Hz), 2.68 m
(1H, 17-H, J = 10.2, 13.0 Hz), 3.80 m and 4.06 m (2H,
OCH2), 5.60 m (1H, CH, J = 4.4, 10.0 Hz), 7.37–
7.86 m (7H, Harom). Found, %: C 62.17; H 3.72;
Cl 8.36; N 3.38. C22H16ClNO6. Calculated, %: C 62.05;
H 3.79; Cl 8.33; N 3.29.
1
(C2=O), 1728 (C11=O, C12=O). H NMR spectrum, δ,
ppm: VIf: 1.11 t (3H, CH3, J = 7.0 Hz), 1.38 t (3H,
4′-OCH2CH3, J = 7.0 Hz), 2.37 m (2H, 17-H), 3.71 m
and 3.83 m (2H, 16-OCH2), 4.18 q (2H, 4′-OCH2, J =
6.9 Hz), 5.75 m (1H, CH), 7.10–8.00 m (8H, Harom);
VIIf: 1.21 t (3H, CH3, J = 7.2 Hz), 1.38 t (3H,
4′-OCH2CH3, J = 7.0 Hz), 2.13 m (1H, 17-H, J = 10.2,
12.8 Hz), 2.62 m (1H, 17-H, J = 4.2, 13.0 Hz), 3.83 m
and 4.06 m (2H, 16-OCH2), 4.18 q (2H, 4′-OCH2, J =
6.9 Hz), 5.58 m (1H, CH, J = 4.0, 10.2 Hz), 7.10–
7.89 m (8H, Harom). Found, %: C 66.29; H 4.84; N 3.19.
C24H21NO7. Calculated, %: C 66.20; H 4.86; N 3.22.
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 08-03-01032).
(1R*,16R*)-14-(4-Bromophenyl)-16-ethoxy-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIg) and
(1S*,16R*)-14-(4-bromophenyl)-16-ethoxy-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraene-2,11,12-trione (VIIg) (mixture of
diastereoisomers at a ratio of ~10:1). Yield 93%,
mp 238–240°C (decomp.). IR spectrum, ν, cm–1: 1794
REFERENCES
1. Denislamova, E.S., Bubnov, N.V., and Maslivets, A.N.,
Russ. J. Org. Chem., 2011, vol. 47, p. 933.
2. Hosoi, S., Nagao, M., Tsuda, Y., Isobe, K., Sano, T., and
1
(C2=O), 1728 (C11=O, C12=O). H NMR spectrum, δ,
Ohta, T., J. Chem. Soc., Perkin Trans. 1, 2000, p. 1505.
ppm: VIg: 1.11 t (3H, CH3, J = 7.2 Hz), 2.38 m (2H,
17-H), 3.71 m and 3.82 m (2H, OCH2), 5.78 m (1H,
CH), 7.32–7.87 m (8H, Harom); VIIg: 1.21 t (3H, CH3,
J = 7.0 Hz), 2.18 m (1H, 17-H, J = 10.2, 12.8 Hz),
2.61 m (1H, 17-H, J = 4.2, 13.0 Hz), 3.84 m and
4.04 m (2H, OCH2), 5.62 m (1H, CH, J = 4.2,
10.2 Hz), 7.32–7.78 m (8H, Harom). Found, %: C 55.98;
H 3.48; Br 17.09; N 3.01. C22H16BrNO6. Calculated,
%: C 56.19; H 3.43; Br 16.99; N 2.98.
3. Sano, T., J. Synth. Org. Chem., 1984, vol. 42, p. 340.
4. Tsuda, Y., Horiguchi, Y., and Sano, T., Heterocycles,
1976, vol. 4, p. 1237.
5. Tsuda, Y., Horiguchi, Y., and Sano, T., Heterocycles,
1976, vol. 4, p. 1355.
6. Maslivets, A.N., Mashevskaya, I.V., Krasnykh, O.P.,
Shurov, S.N., and Andreichikov, Yu.S., Zh. Org. Khim.,
1992, vol. 28, p. 2545.
7. Andreichikov, Yu.S., Voronova, L.A., and Kozlov, A.P.,
Zh. Org. Khim., 1979, vol. 15, p. 520.
(1R*,16R*)-7-Chloro-16-ethoxy-14-phenyl-3,15-
dioxa-10-azatetracyclo[8.7.0.01,13.04,9]heptadeca-
4,6,8,13-tetraen-2,11,12-trione (VIh) and
8. Stepanova, E.E., Babenysheva, A.V., and Maslivets, A.N.,
Russ. J. Org. Chem., 2010, vol. 46, p. 941.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 6 2011