Five-membered 2,3-dioxoheterocycles: LXXXIII. Synthesis and thermolysis of 1-aryl-4,5-diaroyl-1H-pyrrole-2,3-diones

Article abstract of DOI:10.1134/S1070428012020145

The reaction of (Z)-2-amino-1,4-diarylbut-2-en-1,4-diones with oxalyl chloride led to the formation of 1-aryl-4,5-diaroyl-1H-pyrrole-2,3-diones that at the thermal decarbonylation gave aroyl(N-arylimidoyl)ketenes which underwent stabilization by molecular cyclization into 2,3-diaroylquinolin-4(1H)-ones. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S1070428012020145

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 2, pp. 249−252. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © P.S. Silaichev, N.V. Kudrevatykh, A.N. Maslivets, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 2, pp. 259−262.
Five-Membered 2,3-Dioxoheterocycles: LXXXIII.*
Synthesis and Thermolysis
of 1-Aryl-4,5-diaroyl-1H-pyrrole-2,3-diones
P. S. Silaicheva,b, N. V. Kudrevatykhb, and A. N. Maslivetsa,b
aInstitute of Natural Sciences at Perm State University, Perm, 614990 Russia
e-mail: koh2@psu.ru
bPerm State University, Perm, Russia
Received May 19, 2011
Abstract—The reaction of (Z)-2-amino-1,4-diarylbut-2-en-1,4-diones with oxalyl chloride led to the formation
of 1-aryl-4,5-diaroyl-1H-pyrrole-2,3-diones that at the thermal decarbonylation gave aroyl(N-arylimidoyl)ketenes
which underwent stabilization by molecular cyclization into 2,3-diaroylquinolin-4(1H)-ones.
DOI: 10.1134/S1070428012020145
The thermolysis of 4-benzoyl-1,5-diphenyl-1H-pyr-
role-2,3-dione leads to its decarbonylation [elimination
of a molecule of carbon(II) oxide] and to the generation
of a substituted benzoyl(N-phenylimidoyl)ketene that
suffers an intramolecular cyclization through the acyla-
tion by the ketene fragment of the CH group in the ortho-
position of the benzene ring at the nitrogen atom giving
2-phenyl-3-benzoyl-quinolin-4(1H)-one [2]. The forma-
tion as an intermediate of the imidoylketene stable at the
temperature below –70°C we succeeded to detect at the
flash-pyrolysis of this pyrroledione [3]. The thermolysis of
1-aryl-4-aroyl-5-methoxycarbonyl-1H-pyrrole-2,3-diones
proceeded also with CO elimination and the formation of
a substituted aroyl(N-arylimidoyl)-ketene undergoing the
intramolecular cyclization into 3-aroyl-2-methoxycarbon-
ylquinolin-4(1H)-ones [4].
IIa–IIe generated by the thermolysis of these pyrroledio-
nes suggest that in their stabilization besides the above
described way may arise other routes of intramolecular
cyclization, for instance, involving the ortho-position
of the benzene ring of the “new” aroyl fragment along
the scheme analogous to the stabilization of substituted
bis(imidoyl)ketenes [5].
Initial compounds for the synthesis of pyrrolediones
Ia–Ie, (Z)-1,4-diaryl-2-arylaminobut-2-ene-1,4-diones
IIIa, IIIb, were obtained by the reaction of bis(2,5-
dimethylbenzoyl)acetylene with anilines, and enamines
IIIc, IIId [6] and enamine IIIe [7] were synthesized by
known procedures.
Compounds IIIa, IIIb are orange crystalline
substances of low melting points, readily soluble in
common organic solvents, sparingly soluble in alkanes,
insoluble in water.
With the goal to investigate the influence of the in-
troduction of an aroyl fragment into the position 5 of the
1-aryl-4-aroyl-substituted 1H-pyrrole-2,3-diones on the
direction of the stabilization of the generated at their ther-
mal decarbonylation substituted aroyl(N-arylimidoyl)ke-
tenes we synthesized 1-aryl-4,5-diaroyl-1H-pyrrole-2,3-
diones Ia–Ie and studied their thermolysis. The structural
features of the substituted aroyl(N-arylimidoyl)ketenes
The IR spectra of compounds IIIa, IIIb contain the
absorption bands of stretching vibrations of NH group
as a wide band in the region 3150–3160 cm–1, of the
“free” aroyl carbonyl group (1665–1678 cm–1), and of
the aroyl carbonyl group involved in the formation of
intramolecular hydrogen bonds (1600–1605 cm–1).
1
In the H NMR spectra of compounds IIIa, IIIb
––––––––––––––––
solutions in DMSO-d6 alongside the signals of the
*Communication LXXXII see [1].
249

SILAICHEV et al.
250
protons of the aromatic rings and the groups attached
to them a singlet of a vinyl proton (5.70–5.78 ppm) and
a broadened singlet of the NH group involved in the
formation of intramolecular hydrogen bonds (downfield
at 12.04–12.06 ppm) are observed.
Heating of 1-aryl-4,5-diaroyl-1H-pyrrole-2,3-diones
Ia–Ie in an inert aprotic solvent (Dowtherm A) at
210–220°C for 15–20 min (till the end of CO bubbles
liberation) led to the formation in good yields of 2,3-diar-
oylquinolin-4(1H)-ones IVa–IVe.
The spectral characteristics of compounds IIIa,IIIb
show that they exist in the crystalline state and in solution
in the form of Z-isomers with a strong intramolecular
hydrogen bond of an H-chelate type between the NH and
aroyl group as is characteristic of this class substances
[4, 6, 7].
Compounds IVa–IVe are colorless crystalline sub-
stances of high melting points melting with decompo-
sition, readily soluble in DMF and DMSO, sparingly
soluble in common organic solvents, insoluble in water
and alkanes.
The IR spectra of quinolinones IVa–IVe contain the
absorption bands of stretching vibrations of NH group as
a wide band in the region 3200–3265 cm–1, of carbonyl
keto groups of the aroyl substituents, and of carbonyl
group of the quinolone ring as one or two bands in the
region 1635–1682 Cm–1.
At boiling the solution of enamines IIIa–IIIe and oxa-
lyl chloride (1:1.1) in anhydrous benzene over 70–80 min
(till the end of HCl liberation) we obtained the desired
1-aryl-4,5-diaroyl-1H-pyrrole-2,3-diones Ia–Ie. In the
preparation and crystallization of pyrrolediones thor-
oughly dried solvents and freshly distilled oxalyl chloride
should be used: In this case the synthesis proceeds cleanly,
and pyrrolediones Ia–Ie form in good yield.
1
In the H NMR spectra of quinolinones IVa–IVe
alongside the signals of the protons of the aromatic
rings and the groups attached to them a signal is pres-
ent of the proton of the NH as a broadened singlet at
12.77–12.86 ppm.
Pyrrolediones Ia–Ie are orange or bright red crys-
talline substances of high melting point melting with
decomposition, readily soluble in common organic sol-
vents, DMF, and DMSO, insoluble in alkanes, reacting
with water and alcohols, decolorizing at storage due to
thereaction with air moisture.
Spectral characteristics of the quinolin-4(1H)-ones are
fairly similar to those of the model substituted quinolin-
4(1H)-ones [2, 4].
The formation of compounds IVa–IVe proceeds ap-
parently through the primary cheletropic elimination of
the CO molecule resulting in imidoylketenes IIa–IId
which undergo the stabilization due to the acylation
with the ketene fragment of the CH group in the ortho-
The IR spectra of compounds Ia–Ie contain absorption
bands of the stretching vibrations of lactam amd ketone
carbonyl groups of the pyrroledione ring (1770–1779
and 1715–1738 cm–1 respectively), and also the carbonyl
groups bands of the aroyl substituents (1636–1678 cm–1).
H
ArCO
ArCO
O
O
Ar
COAr
C
C
C
N
O
.
.
R
NH2
N
.
(COCl)2
_HCl
H
ArCOC COCAr
R
IIIа_IIIe
R
Iа_Ie
O
Ar
C
O
R
COAr
COAr
R
C
N
C
O
O
Δ
_CO
C
N
H
C
Ar
IVа_IVe
IIа_IIe
R = H (a, c, e), OMe (b, d); Ar =2,5-Me2C6H3 (a, b), Ph (c, d), 4-MeC6H4 (e).
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FIVE-MEMBERED 2,3-DIOXOHETEROCYCLES: LXXXIII.
251
4,5-Dibenzoyl-1-(4-methoxyphenyl)-1H-pyr-
role-2,3-dione (Id). Yield 67%, mp 219–220°C
(decomp., benzene). IR spectrum, ν, cm–1: 1770 (C2=O),
1726 (C3=O), 1678 (C4–C=O), 1641 (C5–C=O). 1H NMR
spectrum, δ, ppm: 3.71 s (3H, OMe), 6.94-8.14 group of
signals (14H, 2Ph + C6H4). Found, %: C 72.96; H 4.17;
N 3.45. C25H17NO5. Calculated, %: C 72.99; H 4.16;
N 3.40.
position of the benzene ring at the nitrogen atom. Thus
the introduction of an aroyl group in the position 5 of
1-aryl-4-aroyl-substituted 1H-pyrrole-2,3-diones did
not change the stabilization direction of the substituted
aroyl(N-arylimidoyl)ketenes generated at their thermal
decarbonylation. The reaction proceeds along the previ-
ously described scheme [2-4].
EXPERIMENTAL
4,5-Di(4-toluoyl)-1-phenyl-1H-pyrrole-2,3-dione
(Ie). Yield 68%, mp 206–207°C (decomp., benzene). IR
spectrum, ν, cm–1: 1775 (C2=O), 1725 (C3=O), 1673 (C4–
C=O), 1647 (C5–C=O). 1H NMR spectrum, δ, ppm: 2.33
s (3H, Me), 2.39 s (3H, Me), 7.18-8.03 group of signals
(13H, Ph + 2C6H4). Found, %: C 76.23; H 4.65; N 3.45.
C26H19NO4. Calculated, %: C 76.27; H 4.68; N 3.42.
IR spectra of compounds obtained were recorded on
a spectrophotometer FSM-1201, 1H NMR spectra were
registered on a spectrometer BrukerAM-400 (400 MHz)
in DMSO-d6, internal reference TMS. The homogeneity
of compounds obtained was confirmed by TLC on Silufol
plates, eluents benzene–ethyl acetate, 5:1, ethyl acetate,
development in iodine vapor or under UV irradiation.
(Z)-1,4-Bis(2,5-dimethylphenyl)-2-phenylami-
nobut-2-ene-1,4-dione (IIIa). A solution of 0.01 mol
of bis(2,5-dimethylbenzoyl)acetylene and 0.01 mol of
aniline in 30 ml of anhydrous benzene was boiled for
5 min (TLC monitoring), 30 ml of warm petroleum ether
(40–70) was added, the solution was cooled, the formed
precipitate was filtered off. Yield 91%, mp 101–102°C
(benzene–petroleum ether, 1:1). IR spectrum, ν, cm–1:
3150 br. (NH), 1678 (C1=O), 1600 (C4=O in intramolecu-
lar hydrogen bond). 1H NMR spectrum, δ, ppm: 2.29 s
(6H, 2Me), 2.39 s (3H, Me), 2.42 s (3H, Me), 5.78 s (1H,
CH), 7.01–7.63 group of signals (11H, Ph + 2C6H3),
12.06 br.s (1H, NH). Found, %: C 81.45; H 6.55; N 3.66.
C26H25NO2. Calculated, %: C 81.43; H 6.57; N 3.65.
4,5-Bis(2,5-dimethylbenzoyl)-1-phenyl-1H-pyr-
role-2,3-dione (Ia). To 0.01 mol of compound IIIa in
50 ml of anhydrous benzene was added dropwise a so-
lution of 0.011 mol of freshly distilled oxalyl chloride
in 10 ml of anhydrous benzene, the mixture was boiled
for 80 min, cooled, the separated precipitate was filtered
off. Yield 67%, mp 213–214°C (decomp., benzene). IR
spectrum, ν, cm–1: 1779 (C2=O), 1715 (C3=O), 1663
(C4–C=O), 1638 (C5–C=O). 1H NMR spectrum, δ, ppm:
2.13 s (3H, Me), 2.28 s (3H, Me), 2.32 s (3H, Me), 2.49 s
(3H, Me), 7.06-7.43 group of signals (11H, Ph + 2C6H3).
Found, %: C 76.83; H 5.35; N 3.22. C28H23NO4. Calcu-
lated, %: C 76.87; H 5.30; N 3.20.
(Z)-1,4-Bis(2,5-dimethylphenyl)-2-(4-methoxy-
phenylamino)but-2-ene-1,4-dione (IIIb) was similarly
obtained. Yield 89%, mp 97–98°C (benzene–petroleum
ether, 1:1). IR spectrum, ν, cm–1: 3160 br. (NH), 1665
(C1=O), 1605 (C4=O in intramolecular hydrogen bond).
1H NMR spectrum, δ, ppm: 2.29 s (6H, 2Me), 2.36 s (3H,
Me), 2.42 s (3H, Me), 3.66 s (3H, OMe), 5.70 s (1H,
CH), 6.78–7.61 group of signals (10H, C6H4 + 2C6H3),
12.04 br.s (1H, NH). Found, %: C 78.45; H 6.56; N 3.37.
C27H27NO3. Calculated, %: C 78.42; H 6.58; N 3.39.
Compounds Ib–Id were obtained in a similar way.
4,5-Bis(2,5-dimethylbenzoyl)-1-(4-methoxy-
phenyl)-1H-pyrrole-2,3-dione (Ib). Yield 65%, mp
213–214°C (decomp., benzene). IR spectrum, ν, cm–1:
1779 (C2=O), 1717 (C3=O), 1663 (C4–C=O), 1636
(C5–C=O). 1H NMR spectrum, δ, ppm: 2.12 s (3H, Me),
2.26 s (3H, Me), 2.31 s (3H, Me), 2.49 s (3H, Me), 3.71 s
(3H, OMe), 6.93–7.36 group of signals (10H, C6H4 +
2C6H3). Found, %: C 74.54; H 5.35; N 3.03. C29H25NO5.
Calculated, %: C 74.50; H 5.39; N 3.00.
2,3-Bis(2,5-dimethylbenzoyl)quinolin-4(1H)-one
(IVa). A solution of 2.5 mmol of compound Ia in 2 ml
of Dowtherm A was heated at 210°C for 15 min (till the
end of CO bubbles liberation), the solution was cooled,
diluted with 10 ml of petroleum ether (40–70), the formed
precipitate was filtered off. Yield 89%, mp 211–212°C
(toluene). IR spectrum, ν, cm–1: 3265 br. (NH), 1668
(C3–C=O), 1635 (C2–C=O, C4=O). 1H NMR spectrum,
δ, ppm: 2.16 s (3H, Me), 2.21 s (6H, 2Me), 2.52 s (3H,
4,5-Dibenzoyl-1-phenyl-1H-pyrrole-2,3-dione
(Ic). Yield 69%, mp 216–217°C (decomp., benzene).
IR spectrum, ν, cm–1: 1772 (C2=O), 1738 (C3=O), 1676
(C4–C=O), 1641 (C5–C=O). 1H NMR spectrum, δ, ppm:
7.04–8.15 group of signals (3Ph). Found, %: C 75.55;
H 3.94; N 3.69. C24H15NO4. Calculated, %: C 75.58;
H 3.96; N 3.67.
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SILAICHEV et al.
252
Me), 7.02–8.11 group of signals (10H, C6H4 + 2C6H3),
12.79 br.s (1H, NH). Found, %: C 79.22; H 5.64; N 3.46.
C27H23NO3. Calculated, %: C 79.20; H 5.66; N 3.42.
lated, %: C 75.19; H 4.47; N 3.65.
2,3-Di(4-toluoyl)quinolin-4(1H)-one (IVe). Yield
92%, mp 286–287°C (toluene). IR spectrum, ν, cm–1:
3200 br. (NH), 1670 (C3–C=O), 1645 (C2–C=O, C4=O).
1H NMR spectrum, δ, ppm: 2.35 s (6H, 2Me), 7.21–8.15
group of signals (12H, 3C6H4), 12.77 br.s (1H, NH).
Found, %: 78.76; H 5.05; N 3.63. C25H19NO3. Calculated,
%: C 78.72; H 5.02; N 3.67.
Compounds IVb–IVh were obtained in a similar way.
2,3-Bis(2,5-dimethylbenzoyl)-6-methoxyquinolin-
4(1H)-one (IVb). Yield 90%, mp 271-272°C (ethyl
acetate). IR spectrum, ν, cm–1: 3250 br. (NH), 1666
(C3–C=O), 1637 (C2–C=O, C4=O). 1H NMR spectrum,
δ, ppm: 2.15 s (3H, Me), 2.21 s (6H, 2Me), 2.52 s (3H,
Me), 3.85 s (3H, OMe), 7.02–7.72 group of signals (9H,
3C6H3), 12.81 br.s (1H, NH). Found, %: C 76.50; H 5.77;
N 3.17. C28H25NO4. Calculated, %: C 76.52; H 5.73;
N 3.19.
REFERENCES
1. Silaichev, P.S., Chudinova, M.A., Slepukhin, P.A., and
Maslivets, A.N., Zh. Org. Khim., 2012, vol. 48, p. 114.
2,3-Dibenzoylquinolin-4(1H)-one (IVc). Yield
91%, mp 248-249°C (toluene–acetonitrile, 1:1).
IR spectrum, ν, cm–1: 3200 br. (NH), 1682 (C3–C=O),
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1647 (C2–C=O, C4=O). H NMR spectrum, δ, ppm:
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7.41–8.16 group of signals (14H, 2Ph + C6H4), 12.85 br.s
(1H, NH). Found, %: 78.16; H 4.25; N 3.99. C23H15NO3.
CычandCлe-HO, %: C 78.18; H 4.28; N 3.96.
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2,3-Dibenzoyl-6-methoxyquinolin-4(1H)-one (IVd).
Yield 89%, mp 256–257°C (ethyl acetate). IR spectrum,
ν, cm–1: 3200 br. (NH), 1670 (C3–C=O, C2–C=O, C4=O).
1H NMR spectrum, δ, ppm: 3.88 s (3H, OMe), 7.40–7.90
group of signals (13H, 2Ph + C6H3), 12.86 br.s (1H, NH).
Found, %: C 75.15; H 4.40; N 3.63. C24H17NO4. Calcu-
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 2 2012