FORMATION OF N,N'-DI(5-ALKOXYCARBONYL-5-METHYL-2-OXO-1-
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5-methyl-2-oxo-1-phenyl-2,5-dihydro-1Н-pyrrol-3-yl)-
N,N'-diphenyloxalylamides V, VI were isolated for the
first time.
The formation of compounds V, VI occurred appar-
ently through the acylation of initial enamines I, II, in
the first stage of the reaction. The formerly unknown
compounds V, VI synthesized are colorless crystalline
substances soluble in DMF, DMSO, and at heating in
acetonitrile, ethyl acetate, acetic acid. The IR spectrum of
compound V contains the absorption bands of the stretch-
ing vibrations of the ester carbonyl group (1748 cm–1) and
amide carbonyl groups (1672–1712 cm–1).
In the 1Н NMR spectra of compounds V, VI alongside
the signals of the aromatic protons the singlet of three
protons of the methyl group attached to the position 5
appears in the region 1.53–1.56 ppm, a singlet of the
methoxycarbonyl group in the region 3.65–3.71, triplet
and quartet of the ethoxycarbonyl group in the region
1.15 and 4.10 ppm are also present.
In order to establish the spatial arrangement of
compounds V, VI a single crystal of compound VI was
obtained by slow crystallization from acetic acid, and it
was subjected to XRD analysis (see the figure).
Structure of the molecule of N,N'-di(5-ethoxycarbonyl-5-
methyl-2-oxo-1-phenyl-2,5-dihydro-1Н-pyrrol-3-yl)-N,N'-
diphenyloxalylamide (VI) according to XRD data
To a solution of 1.0 mmol of compound I, II in 30 ml
of anhydrous tetrachloromethane was added 1.0 mmol
of oxalyl chloride, and the mixture was boiled for 3–4 h.
Then the reaction mixture was cooled, the formed pre-
cipitate of compound V, VI was filtered off, the filtrate
was evaporated to isolate compound III, IV.
N,N'-Di(5-methyl-5-methoxycarbonyl-2-oxo-
1-phenyl-2,5-dihydro-1Н-pyrrol-3-yl)-N,N'-di-
phenyloxalylamide (V). Yield 1.2 g (31%), mp 275–
277°С (acetic acid). IR spectrum, ν, cm–1: 1716 (C=O),
1704 (C=O), 1692 (C6=O). 1Н NMR spectrum, δ, ppm:
1.53 s (3Н, СН3), 3.65 s (3Н, ОСН3), 7.01–7.32 m (10Н,
2C6H5). Found, %: С 75.86; H 4.80; N 8.05. С40Н34N4О8.
Calculated, %: С 68.76; H 4.90; N 8.02.
Methyl 4-methyl-2,3,6-trioxo-1,5-diphenyl-
1,2,3,4,5,6-hexahydropyrrolo[3,4-b]pyrrole-4-
carboxylate (III). Yield 2.2 g (51%), mp 191–193°С.
IR spectrum, ν, cm–1: 1745 (C=O), 1738 (C2=O), 1730
(C3=O), 1705 (C7=O). 1Н NMR spectrum, δ, ppm:
1.64 s (3Н, СН3), 3.71 s (3Н, OСН3), 7.23–7.36 m (10Н,
2C6H5). Found, %: С 70.07; H 4.23; N 7.50. С21Н16N2О5.
Calculated, %: С 67.02; H 4.28; N 7.44.
N,N'-Di(5-ethoxycarbonyl-5-methyl-2-oxo-
1-phenyl-2,5-dihydro-1Н-pyrrole-3-yl)-N,N'-
diphenyloxalylamide (VI). Yield 1.4 g (34%), mp 247–
249°С (acetic acid). IR spectrum, ν, cm–1: 1748 (C=O),
1712 (C=O), 1672 (C6=O). 1Н NMR spectrum, δ, ppm:
1.15 t (3Н, СН3, J 7 Hz), 1.56 s (3Н, СН3), 4.10 q (2Н,
СН2CH3, J 7.5 Hz), 7.19–7.32 m (10Н, 2C6H5). Found,
%: С 73.52; H 5.25; N 7.60. С42Н38N4О8. Calculated, %:
С 69.41; H 5.27; N 7.71.
Ethyl 4-methyl-2,3,6-trioxo-1,5-diphenyl-
1,2,3,4,5,6-hexahydropyrrolo[3,4-b]pyrrole-4-carb-
oxylate (IV). Yield 2.4 g (53%), mp 193–195°С. IR
spectrum, ν, cm–1: 1744 (C=O), 1736 (C2=O), 1728
1
(C3=O), 1708 (C6=O). Н NMR spectrum, δ, ppm:
IR spectra were recorded on a spectrophotometer
Specord M-80 from mulls in mineral oil. 1Н NMR spectra
were registered on spectrometers Bruker DRX 300 and
DRX 500 in DMSO-d6, internal reference TMS. XRD
experiment was carried out on an automatic four-circle
1.15 t (3Н, СН3, J 7 Hz), 1.66 s (3Н, СН3), 4.10 q (2Н,
СН2CH3, J 7.5 Hz), 7.09–7.36 m (10Н, 2C6H5). Found,
%: С 72.59; H 4.75; N 7.15. С22Н18N2О5. Calculated, %:
С 69.69; H 4.65; N 7.18.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 2 2012