Synthesis and thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones, pseudopericyclic reactions of formyl(N-phenylimidoyl)ketene: Experimental data and PM3 calculations

Article abstract of DOI:10.1002/jhet.5570420507

The reactions of the 2,3-dihydro-1H-furan-2,3-dione 1 with Schiff bases 2a-f at 60-70°C furnish the corresponding 2,3-dihydro-1H-pyrole-2,3-diones 3a-f. The heating of 3a-d afforded the corresponding 4-methoxybenzoyl(N- arylimidoyl)ketenes 4a-d as intermediates which undergo a very facile cyclization to quinoline-4-ones 5a-d. According to our PM3 calculations, fragmentation of 4-formyl-2,3-dihydro-1H-pyrole-2,3-dione and 1,4-cyclization of formyl(N-phenylimidoyl)ketene IN1 to azetin-2-one IN2 and oxetone IN3 are pseudopericyclic reactions with two orbital connections, proceed via planar transition structures. Due to to the possibility of syn and anti conformations of the imine phenyl, there are eight E/Z-isomers of IN1. In addition, we have also calculated reaction mechanism of formation of quinoline-4-ones by the PM3 method.

Full text of DOI:10.1002/jhet.5570420507

Jul-Aug 2005
787
Synthesis and Thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones,
Pseudopericyclic Reactions of Formyl(N-phenylimidoyl)ketene:
Experimental Data and PM3 Calculations.
Emin Sarıpınar* and Süleyman Karatas¸
Department of Chemistry, Arts and Sciences Faculty, Erciyes University, 38039 Kayseri- Turkey
Received July 14, 2004
The reactions of the 2,3-dihydro-1H-furan-2,3-dione 1 with Schiff bases 2a-f at 60-70°C furnish the cor-
responding 2,3-dihydro-1H-pyrole-2,3-diones 3a-f. The heating of 3a-d afforded the corresponding 4-
methoxybenzoyl(N-arylimidoyl)ketenes 4a-d as intermediates which undergo a very facile cyclization to
quinoline-4-ones 5a-d. According to our PM3 calculations, fragmentation of 4-formyl-2,3-dihydro-1H-
pyrole-2,3-dione and 1,4-cyclization of formyl(N-phenylimidoyl)ketene IN1 to azetin-2-one IN2 and oxe-
tone IN3 are pseudopericyclic reactions with two orbital connections, proceed via planar transition struc-
tures. Due to to the possibility of syn and anti conformations of the imine phenyl, there are eight E/Z-iso-
mers of IN1. In addition, we have also calculated reaction mechanism of formation of quinoline-4-ones by
the PM3 method.
J. Heterocyclic Chem., 42, 787 (2005).
Introduction.
widely studied than α-oxoketenes [13], they undergo a
rich variety of reactions.
The oxa-1,3-diene moiety in 4-acyl substituted hetero-
cylic 2,3-diones, e.g., 2,3-dihydro-1H-furan-2,3-diones or
2,3-dihydro-1H-pyrole-2,3-diones add various isocyanides
[1], isocyanates [2], carbodiimides [3], ketenimines [4],
diphenylketene [5], imines [6], and alkenes [7], via [2+2],
[4+1], or [4+2] cycloaddition processes affording novel
mono- and bicyclic systems. The primary formed
cycloadducts are not stable and undergo unusual furan-
In this paper, the synthesis and characterization of the
2,3-dihydro-1H-pyrole-2,3-diones derivatives 3a-f
obtained from the reactions between various imine deriva-
tives 2a-f and 2,3-dihydro-1H-furan-2,3-diones 1 are pre-
sented, our findings during the course of synthesizing 3a-
d, too, as well as further investigations of its thermal
decomposition and cyclization to quinolones 5a-d at high
temperatures. To study the mechanism of the reaction all
calculations were carried out by means of semiempirical
PM3 method [14] with full geometry optimisation for
reactants, products and intermediates. The PM3 calcula-
tions were carried out using the SPARTAN program pack-
age [15]. Transition structures have been located using the
linear synchronous transition method contained within
Spartan. Vibrational mode analyses were systematically
carried out to confirm that on a potential energy surface all
optimized geometries correspond to a local minimum that
has no imaginary frequency mode or a saddle point that
has only one imaginary frequency mode. Model com-
pounds with aryl and phenyl groups substituted by hydro-
gen atoms were used in the theoretical calculations. The
17
dione rearrangements, made evident by O-labeling
experiments [8]. The effect of substitiuent on the site
selectivity (C=C vs C=N) in the [4+2] cycloaddition
between ketene imines with heterodienes (acrolienes or 4-
acyl-2,3-dihydro-1H-furan-2,3-diones) was treated by
semiempirical molecular orbital AM1, density functional
calculations using Becke's three-parameter hybrid
(B3LYP/6-31G*) and ab initio method [9]. N-
Phenylimino-2,3-dihydro-1H-furan-2,3-diones, obtainable
e.g. by reactions of 4-acyl-2,3-dihydro-1H-furan-2,3-
diones with tosylsulfinylamines or arylalkylcarbodiimides
or imines, thermally rearrange to 4-acyl-2,3-dihydro-1H-
pyrole-2,3-diones [3a,6b,8b]. Semiempirical molecular
orbital calculations were used to rationalize this behavior
[10]. Thermal decarbonylation of 4-acyl-2,3-dihydro-1H-
pyrole-2,3-diones leads to the formation of highly reactive
acyl(N-arylimidoyl)ketenes. The acyl(N-arylimidoyl)-
ketenes cyclize very easily to quinolones [11]. Imidoyl-
ketenes are also generated by flash vacuum thermolysis of
Meldrum's acid [11b,g,h], triazole derivatives [11e,f,g] and
the elimination of alcohols from enamine ester [12]. These
reactions proceed readily at temperatures ranging from
160 to 185 °C in static systems or above 300 °C under fvp
conditions [11b,d,e]. Imidoylketenes are closely related to
formylketene; the substituents in both possess a π-bond in
conjugation with the ketene as well as an in-plane lone
pair. Although substituted imidoylketenes have been less
results of the calculations (the formation entalpies ∆H , in
f
-1
kcalmol ; dipole moments µ, in debye; the highest and
lowest molecular orbital energies E
eV and lowest or imaginary frequencies, in cm ) are
given in Table 1.
and E
, in
HOMO
LUMO
–1
Results and Discussion.
Treatment of the yellow 4-(-4-methoxybenzoyl)-5-(-4-
methoxyphenyl)-2,3-dihydro-2,3-furandione 1 with Schiff
bases 2a-f at 60-70 °C furnishes the corresponding red
coloured 2,3-dihydro-1H-pyrole-2,3-diones 3a-f. The
reaction equation is shown in Scheme 1. The structures of
1
13
3a-f were confirmed by elemental analysis, IR, H and
C

788
E. Sarıpınar and S. Karatas¸
Vol. 42
Table 1
3.84, 3.69 (two s, 2OCH ) ppm. The reaction of 1 with
3
Relative energies, dipole moments, HOMO and LUMO orbital
energies and imaginary frequencies for the reactants R, transition
states TS, intermediates IN and products P.
N,N'-bis(benzylidene)ethane-1,2-diamine 2e and N,N'-
bis(benzylidene)benzene-1,4-diamine 2f at 60 °C fur-
nishes the corresponding red coloured 1,2-bis[4-(4-
methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-dihydro-1H-
pyrrole-2,3-dione-1yl]ethane 3e and 1,4-bis[4-(4-
methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-dihydro-1H-
pyrrole-2,3-dione-1-yl]benzene 3f, respectively (see
Experimental). The reaction equations are shown in
Scheme 1.
-1
Compounds
∆H
kcalmol
µ
E
eV
E
eV
ν cm
rel
HOMO
LUMO
-1
Debye
R1
-43,30
-15.91
-13.88
0
2.31
2,62
3,29
3.76
5.43
9.75
11,53
20.25
15.74
17.75
34.94
33.51
27.42
2.00
34.09
-28.22
-26.97
-31.26
3.87
0.18
0.80
2.08
2.17
0.86
3.53
1.11
3.72
3.92
3.58
4.76
4.75
4.95
3.68
4.48
4.09
4.08
4.09
5.64
5.13
0.69
-10.56 -1.42
-13.03 1.00
49.83
CO
TS1
2306.00
365.25i
34.09
31.82
30.54
33.19
33.57
27.39
49.88i
27.46i
340.93i
44.32
161.41i
519.11i
36.92
835.56i
48.20
1600.44i
41.88
-9.12
-9.30
-9.19
-9.25
-9.30
-9.21
-9.16
-8.88
-8.72
-8.60
-9.05
-8.74
-8.96
-9.27
-9.25
-9.48
-9.54
-8.93
-9.35
-9.20
-0.46
-0.31
-0.48
-0.56
-0.31
-0.56
-0.74
-0.61
-0.73
-1.01
-1.12
-1.09
-0.82
-0.97
-0.57
-1.74
-1.67
-0.73
-1.12
-1.08
IN1-ZZ
IN1-EZ
IN1-ZZ
IN1-ZE
IN1-ZE
IN1-EZ
IN1-EE
IN1-EE
TS2
(anti)
(anti)
(syn)
(anti)
(syn)
(syn)
The heating of 2,3-dihydro-1H-pyrole-2,3-diones 3a-d
under thermolytic conditions afforded the corresponding
1H-quinolin-4-one derivatives 5a-d in moderate to accept-
able yields (40-52 %), obviously obtained as a result of
thermolysis of the primary formed 4-methoxybenzoyl(N-
arylimidoyl)ketenes 4a-d generated immediately under-
goes a 6π electrocyclic ring closure to afford the quinoline
derivative 5 during warm-up. The reaction equation is
shown in Scheme 2. This case is well known from other
N-aryl-imidoylketenes [2c], irrespective from which pre-
cursor they were generated and independent of the ther-
molytic or pyrolytic reaction conditions employed [11a].
In the ir spectra of compound 5a, the N-H and C=O
absorption bands were found to be at about 3360, 1670,
(syn)
(anti)
IN2
IN2
(pyramidal)
(planar)
TS3
IN3
TS4
IN4
TS5
P1
P2
P3
57.13
83.37
-1
1
and 1630 cm , respectively (see Experimental). H nmr
signals about 5a were found at δ = 12.01 (s, NH or OH),
nmr data. Product 3a was obtained by reacting 1 with N-
benzylidene aniline 2a in 83 % yield. In the ir spectra of
compound 3a, the C=O absorption bands were found at
8.14-6.94 (m, Ar-H) and δ = 3.81, 3.76 (two s, 2xOCH )
ppm. In particular from the C nmr spectrum of 5a,
3
13
important structural information can be obtained. δ Values
of 195.96 and 176.84 ppm for the carbon atoms at ArCO
and C-4 are in good accordance with those of very close
analogues having identical 1H-quinolin-4-one ring sys-
tems [2b,c,3a]. Elemental analysis data and more informa-
tion about the 5a-d spectra were given in the Experimental
section.
-1
about 1750, 1710 and 1640 cm , typical of pyrrole-2,3-
diones [3a]. The basic structure of 3a is strongly sup-
13
ported by C nmr found at 187.79 (t, j = 3.7 Hz, ArCO),
179.28 (s, C = O), 162.30 (s, C = O), 172.02 (s, C-5),
3
2
1
113.91 (s, C-4), 55.85(OCH ) and 55.68 ppm (OCH ). H
3
3
nmr signals were found at δ = 7.97-6.74 (m, Ar-H) and δ =

Jul-Aug 2005
Synthesis and Thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones
789
Table
Selected structural data and Mulliken charges ( e)
for R1, TS1 and IN-ZZ
2
The reaction mechanism for selected model structures,
formation of formyl(N-phenylimidoyl)ketene IN1, its con-
formational structures and N-phenylacylazetion IN2 and
N-phenylimodyloxetone IN3 equilibrium have been
resulted by PM3 calculations. A comprehensive theoreti-
-
.
(anti)
Atom Charges
R1
TS1
-0.188
IN-ZZ
(anti)
cal study of the electrocyclization of IN1-ZZ
was con-
N1
C2
C3
C4
C5
O6
07
0.077
0.195
0.325
-0.432
0.049
-0.246
-0.239
0.365
-0.335
-0.120
(anti)
0.110
0.514
-0.476
0.092
-0.166
-0.136
0.370
-.332
ducted. The study included a conformational analyis of the
reactants, locating transition structures and optimizing
closed products. The spatial dispositions of atoms for the
reactant R, intermediates IN, transition states TS and
products P are shown in Figures 1-4. To ease the consider-
ation of changes in the systems, the same numbering of
atoms is kept for reactants, transition states, intermediate
and final products of the reactions.
0.484
-0.471
0.056
-0.105
0.377
-0.357
C8
O9
Bond Lengths
N1-C2
1.462
1.553
1.482
1.363
1.418
1.202
2.099
2.475
1.350
1.446
1.304
1.162
Thermolysis of R1 leads to the formation of IN1 as an
intermediate (see Figure 1). As seen from Table 1, the
molecule CO disconnection is realized through a transi-
C2-C3
C4-C3
C5-C4
C5-N1
1.345
1.454
1.295
1.158
tional state TS1 with the value of ∆H equal to –13.88
rel
O7-C3
-1
kcal.mol . The characteristic structural variations for the
Bond Angles
reacting molecules are given in the Table 2. The calcu-
lated transition structure TS1 for the decarbonylation of
R1 is shown in Figure 1. The TS1 is formed when the
atom C2 moves to the distance of 2.099 and 2.475 Å from
the atoms N1 and C3, respectively. TS1 is an asynchro-
nous transition structure and the reaction is concerted.
The C2-C3 bond breaking to a greater degree in TS1,
rather than the amide N1-C2 bond; because amides are
stabilized and α-dicarboyl compounds are destabilized.
Because of unsaturated carbonyl structure of pyrrole-2,3-
dion, nitrogen gives its lone pair easily to C5 rather then
to C2. Bond orders of C5-N1, N1-C2 and C2-C3 at the
R1 are 1.145, 0.958 and 0.829, respectively. However,
the nearly linear O7-C3-C4 geometry (168.28°) suggests
that it is more appropriate to consider the reverse reac-
tion, the interaction of CO with formyl(N-phenylimi-
doyl)ketene, in which donation of the CO lone pair to the
in-plane ketene LUMO is the dominant interaction, and
leads to the nearly linear geometry.
C3-C2-N1
C6-C2-C3
O7-C3-C4
C5-N1-C2
105.49
129.73
130.73
108.25
77.68
171.51
168.29
114.07
179.52
Torsion Angles
N1-C2-C3-C4
C2-C3-C4-C5
O6-C2-C3-C4
C5-N1-C10-C11
-0.21
0.06
177.94
-179.98
-13.25
12.56
-167.10
-129.25
almost planar) transition states and low activation energy
[12,16]. Decarbonylation of 2,3-dihydro-1H-furan-2,3-
diones or 2,3-dihydro-1H-pyrole-2,3-diones are pseudo-
pericylic reactions that proceed via planar transition
structure [17]. For decarbonylation of 4-acyl-2,3-dihy-
dro-1H-pyrole-2,3-dione R1, a pseudopericyclic orbital
topology is possible, with two orbital disconnections, i.e.
two atoms where orthogonal sets of orbitals meet, but do
not overlap. Because no electrons are exchanged between
the in-plane and out-of plane orbitals, the transition state
for R1 is orbital symmetry allowed when the CO departs
in the plane of the molecule. The near planarity of TS1
and the short C=O bond predict that the carbon monoxide
product should be formed rotationally and vibrationally
cold. Furthermore, the pseudopericyclic orbital topology
of this reaction, combined with favorable interactions
between electrophilic and nucleophilic centers, results in
barriers substantially lower than would be expected for
pericyclic decarbonylation analogous. This nearly planar
transition structure is in contrast to other pericyclic reac-
tions, where the transition states are usually nonplanar so
as to maximize orbital overlap [17a]. Two views of the
structures of R1, TS1 and IN1 are shown in Figure 1. 4-
Acyl-2,3-dihydro-1H-pyrole-2,3-dione groups of the two
structures, R1 and TS1, are remarkably similar, as can be
In a recent series of publications, Birney at al. has
reported a number of examples for thermal pseudoperi-
cyclic reactions that include cycloadditions, sigmatropic
rearrangements and electrocyclizations. Such pseudoper-
icyclic reactions are typically characterized by planar (or
Figure 1: Atom numbering scheme and structures for R1, TS1 and IN.
o
Two side views, rotated by approximately 90 , are given.

790
E. Sarıpınar and S. Karatas¸
Vol. 42
seen most clearly in the side views. All of the atoms are
nearly in the same plane at R1, with the exception of
phenyl groups at TS1. Torsion angle C5-N1-C10-C11 of
R1 and TS1 are –179.98 and –129.25° respectively.
Charge of N1 at the R1 is partial positive. As a result of
classes of the carbonyl compound. The E conformers of
formylketene or imodylketenes are calculated to be less
stable than the Z conformer, presumably because of
dipole-dipole interactions. D. M. Birney calculated four
conformers of imidoylketene, due to the possibility of syn
and anti conformations of the imine hydrogen [20].
According to our PM3 calculations, formyl(N-phenylimi-
doyl)ketenes IN1 are mixtures of E and Z isomers. Due to
to the possibility of syn and anti conformations of the
imine phenyl, there are in fact eight isomers of IN1.
Conformational structures of IN1 are shown in Figure 2.
Carbonyl, imino and ketene groups are planar, except for
phenyl group. The relative energies of the conformation
isomers of IN1 are shown in Table 1. According to these
3
2
the rehybridization of N1 from sp toward sp , there is an
increase in negative charge from 0.077 au, to -0.120 au
(at IN1-ZZ
) (see Table 2). Calculated charge densi-
(anti)
ties of isomers of formyl(N-phenylimidoyl)ketenes IN1
show the highest positive charge on C3 (q=0.484-
0.385au), so that nucleophilic attack is expected to occur
at C3. The molecular structures of IN1 has now been
refined and distinguished by short C3-C4 and C3-O7
bond lengths of about 1.345 and 1.158 Å, respectively,
involving the sp-hybridized carbon. The bond angles of
data, IN1-ZZ
conformation should be slightly more
(anti)
O7-C3-C4 for R1 TS1 and IN1-ZZ
are calculated as
stable than the other conformations. Steric and electronic
congestion between the C8=O9 and C5=N1 groups in the
IN1-EE isomer forms of formyl(N-phenylimidoyl)ketene
has been suggested as the origin of the conformational
(anti)
130.73° 168.29° and 179.52°, respectively. The atom C3
2
conversion from sp -hybridized state of R1 to the linear
sp-hybridized state leads to IN1 being planer.
In general, oxoketenes are mixtures of Z and E isomers.
Both experimental and theoretical methods were employed
to study the conformational behaviour of oxo-ketene mol-
ecules [16b,18]. The conformational stability and the size
of the rotational barrier of the oxo-ketenes were found to
be greatly influenced by the extent of the interaction
between the CO and both the C=C=O group and the sub-
stituent plays the major role in determining the direction of
the conformational equilibrium in these molecules [19]. Ab
initio calculations on a series of differently substituted
imodoyl-ketenes were used to investigate E/Z-isomerism
and rotational barriers in these molecules [20].
prefence for IN1-ZZ
. IN1-EE
and IN1-EE
(anti)
(syn) (anti)
2
The preferred conformation of planar systems with sp
carbon atoms can result partly from stereoelectronic
effects and steric repulsion. In the usual conformation of
formylketenes or imidoylketenes, the C=O or C=N- lone
pair is Z to the C=C=O groups, and can interact with the
ππ
orbital. The electron-affinity of the ππ
orbital
C4C3O7
C3O7
Figure 2: Views of calculated geometries of intermediates, IN1.
of the ketene is the highest one, in comparison to the other

Jul-Aug 2005
Synthesis and Thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones
791
conformations of IN1 are unstable in energy. Relative
Birney and coworkers have previously shown that the
relative energies of oxo-ketenes conformers do not corre-
late with the dipole moments [6b,18d]. In the case of
formyl(N-phenylimidoyl)ketenes the same result has been
obtanined by using PM3 calculations methods. For exam-
energy of IN1-EE
kcal.mol , respectively. Electron density is distributed
and IN1-EE
are 9.75, 11.53
(anti)
(syn)
-1
between the carbonyl and imino groups in IN1-EE
and
(syn)
IN1-EE
(see Figure 2). These structures represent the
(anti)
transition state on the potential energy surface. The imagi-
ple, IN1-ZZ
has the lowest dipole moment (0.86D),
(syn)
-1
nary frequencies of IN1-EE
and IN1-EE
are
but the third highest relative energy (2.62 kcal.mol ) as
compared to IN1-ZZ
We have studied the ring-closure of the formyl(N-
phenylimidoyl)ketenes IN1-EZ to cyclic N-phenyla-
(syn)
(anti)
-1
49.88 and 27.46 icm respectively. Steric hindrance would
also be expected to play a role in the conformational pref-
erence of IN1-EE, although electronic factors may also be
important. The most dramatic distortions are seen in the
.
(anti)
(anti)
cylazetion IN2 and N-phenylimodyloxetone IN3 (see
Figure 3). Energetic aspects obtained for the two cycliza-
tions are collected in Table 1. Involvement of the lone pair
of nitrogen or oxygen atom is expected to facilitate the
interaction between the vacant carbon p orbital of the
ketene LUMO and lone pair electrons of nitrogen or oxy-
gen atom, but azetin-2-one and oxetone-2-one cycles are
unstable [16b,17b,18a,c,21]. Azetin-2-ones are rather elu-
sive compounds requiring sterically protecting groups
such as adamantyl or tert-butyl for stabilization under
ordinary reaction conditions [11c]. Alajarin et al. have
carried out ab initio calculations showing that the energy
barrier for the ring closure of N-formylimidoylketene to N-
formylazetone is 23.24 kcal.mol , being an endotermic
process [21c].
Bond orders of N1-C3 and O9-C3 at IN1-ZZ
ture are 0.038 and 0.027 respectively. Electronic repulsion
between O9 and C3 is weaker than that between N1 and
C3. Ring-closure of the formyl(N-phenylimidoyl)ketenes,
C8-C4-C5 angles. In IN1-EE
, this angle is 10.24°
(anti)
wider than in IN1-ZZ
in order to accommadate the
(anti)
two electron withdrawing groups (C=O, C=N) and steric
hindrance between the imino phenyl and carbonyl groups
(C=O). The C8-C4-C5 angle in IN-EE
is 3.04, bigger
(anti)
then that in IN1-EE
. The C4-C5-N1 angle in IN1-
(syn)
EE
is 133.81°, which is larger than the IN1-EE
,
(anti)
(syn)
121.61°. An alternative model, which offers a more consis-
tent explanation of the stability of the IN1-EZ or IN1-ZE
forms, except for IN1-EE conformations, is based on the
electrostatic interactions of the array of atomic charges.
The central carbon, C3, of the formyl(N-phenylimidoyl)-
ketene IN1 functionality bears a partial positive charge
(0.484-0.385 au ) and the carbonyl oxygen (-0.363- -0.289
au) and imino nitrogen (-0.088 - -0.120au) bear a partial
negative charge. The Z conformations bring these charges
into close proximity and, thus, should be stabilized by the
electrostatic attraction between these three centers. Due to
partial negative charge effect between the C8=O9 and
-1
struc-
(anti)
the IN1-ZZ
, to cyclic azetin-2-one IN2 and oxetone-
(anti)
C5=N1 groups at IN1-EE
atom charges enforce a
2-on IN3 is computed to be higher in energy than that of
IN1-ZZ . We located the transition states TS2 and TS3
(anti)
lesser degree of charge separation (see Figure 2). The
charge of C3 at IN1-EE and IN1-EE is 0.398 and
(anti)
for this isomer. The barriers for these are comparable,
(syn)
(anti)
-1
-1
0.385 au, respectively. Since electronic interactions of the
nucleophylic imine nitrogen with electrophylic ketene car-
bon C3 is more than carbonyl oxygen lone pair with C3,
20.25 kcal.mol for TS2 and 34.94 kcal.mol for TS3.
There is a good match between the nucleophilic imine
nitrogen and electrophlic ketene carbon of IN-ZZ
iso-
(anti)
IN1-EZ
and IN1-ZE
conformer is lower energy than IN-ZE
mer, which favors the reaction than between oxygen and
C3. Also, resonance in amides is stronger than in esters,
thus lactam TS2 and IN2 is stabilized more than TS3 and
IN3. At TS2, the distance of C3-N1, which can be consid-
ered as the reaction coordinate, reaches 1.831 Å. This is
(anti)
(anti)
, thus, more stable than the corresponding,
(syn)
and as there is no interaction between the lone pairs of O8
and N1 with C3 in IN1-EZ , this conformation is less
stable than IN1-ZE
(syn)
(syn).
o
Figure 3: Atom-numbering scheme and structures for TS2, TS3, IN2 and IN3.. Two side views, rotated by approximately 90 , are given for TS2 and TS3.

792
E. Sarıpınar and S. Karatas¸
Vol. 42
very close to the value 1.544 Å in the ring IN2 (see
cyclization of IN-ZZ
to generate IN3 was also
(anti)
Table 3). Our calculations show that the formation energy
located. The geometry of TS3 is remarkably similar to the
ring closing transition state TS2 described above. The fre-
quency analysis confirmed both structures IN3 and
-1
of IN1-ZZ
lies 15.74 kcal.mol below that of its
(anti)
cyclic isomer IN2
and it undergoes ring-closure
(pyramidal)
-1
with an energy barrier of 20.25 kcal.mol . The azetin-2-
ones, IN2, possesses the additional feature that resonance
of the carbonyl groups leads to formally anti-aromatic
structure. This suggests that the ring IN2 is thermodynam-
ically less stable than open forms of IN1. Regarding the
structural features of azetone-2-one IN2, the pyramidal
geometry of the nitrogen atom is remarkable. The degree
of pyramidalization can be measured by the sum of the
bond angles at the nitrogen atom, which is 339.35°. The
planar structure of IN2 is characterized as a transition
structure for nitrogen inversion. There is only one imagi-
nary vibrational frequency in the transition state, ν =
IN2
as minima, isomer IN2
being the
(pyramidal)
(pyramidal)
–1
most stable one by 15.74 kcal.mol .
In the case of electrocyclic reactions the 1,4-cyclization
of IN1-ZZ to both IN2 and IN3 were found to be pro-
(anti)
ceed in a pseudopericyclic manner, by in plane attack of
the lone-pair of electrons on the imine nitrogen or carbonyl
oxygen to the electrophilic ketene carbon, respectively.
The most prominent feature of TS2 and TS3 are complete
planarity (N1-C3-C4-C5=0.00° and C3-C4-O8-C9 = -
0.18°), conforming the pseudopericyclic nature of this ring
closure reaction. The IN2 cyclization requires an Z
(anti)
configuration of the imine group as in IN1-ZZ
so that
(anti)
-1
161.41 icm . The analysis of the hessian eigenvector asso-
the lone pair of electrons on the imine nitrogen is oriented
toward the ketene functionality. Note that for this cycliza-
tion mode no rotation of the imine group is required which
therefore can be designated as a ''nonrotatory'' cyclization.
The N1-C3 bond distance changes, but the N1-C3-C4-C5
system remains essentially planar. Our calculations show
that, TS2 and TS3 are associated with a concerted process
whose primary changes in bonding compass a cyclic array
of atoms, where nonbonding and bonding atomic orbitals
interchange their roles. The geometric and electronic fea-
tures of both transition structures, TS2 and TS3, do not
correspond to those expected for a conrotatory mecha-
ciated with this frequency indicates that the bond is bend-
ing rather than stretching. The sum of the bond angle at the
nitrogen atom in the planar IN2 structure is 359.99°, which
is showing an almost planar geometry. This value is nearly
equal to the corresponding value of N-formylazeton [21c].
The inversion energy barrier from pyramidal IN2 to planar
-1
structure of IN2 is 2.01 kcal.mol . The value for unsubsti-
-1
tuted azetidin-2-one has been found to be 5.8 kcal.mol by
Nguyen [18a]. The angle O7-C3-C4 in pyramidal structure
IN2 is lower than the planar structure IN2
(142.77:144.28). A transition structure TS3 for the electro-
Table 3
Selected structural data and Mulliken charges for IN-ZZ
, IN2
, IN3, TS2 and TS3.
(anti)
(pyramidal)
Atom charges
IN1-ZZ
TS2
IN2
TS3
IN3
(anti)
(pyramidal)
N1
C3
C4
C5
07
-0.120
0.484
-0.471
0.056
-0.105
0.377
0.377
-0.153
0.532
-0.531
0.130
-0.186
0.338
0.338
-0.054
0.404
-0.429
0.070
-0.224
0.373
0.373
-0.085
0.526
-0.029
0.452
-0.298
0.012
-0.223
0.149
0.149
-0.404
0.038
-0.178
0.275
0.275
C8
O9
Bond Lengths
N1-C3
C4-C3
C5-C4
C5-N1
O7-C3
C8-O9
C3-O9
2.782
1.345
1.454
1.295
1.158
1.214
2.827
1.831
1.458
1.409
1.360
1.169
1.215
3.058
1.544
1.504
1.363
1.458
1.189
1.209
3.171
3.065
1.464
1.433
1.296
1.169
1.331
1.713
3.153
1.508
1.437
1.292
1.185
1.402
1.495
Bond Angle
N1-C3-C4
C8-O9-C3
N1-C5-C4
O7-C3-C4
C8-C4-C5
79.87
85.72
84.19
119.55
157.75
134.91
87.57
119.50
148.81
136.03
119.77
179.52
119.77
98.18
157.36
131.73
94.71
142.77
133.92
Torsion Angle
C3-C4-C8-C9
N1-C3-C4-C5
0.00
0.00
-0.19
0.00
13.20
-4.33
-0.18
-2.62
0.00
0.02

Jul-Aug 2005
Synthesis and Thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones
793
Table 4
nism. The bond angles, O7-C3-C4, for IN1-ZZ
, TS2,
(anti)
Selected structural data and Mulliken charges for IN-ZZ
TS5 and P1.
, IN4, TS4,
IN2, TS3, and IN3 are 179.52, 157,36, 142.77, 157.75°,
and 148.81°, respectively.
(syn)
A transition structure TS4 for the electrocyclization of
Atom Charges
IN-ZZ
TS4
IN4
TS5
P1
(syn)
IN1-ZZ
to generate IN4 was also located (see Figure 4).
(syn)
N1
C3
C10
C11
H13
-0.088
0.454
-0.053
-0.123
0.114
-0.215
0.493
0.150
-0.315
0.194
-0.127
0.349
0.053
-0.109
0.122
-0.144
0.392
0.071
-0.251
0.232
0.224
0.349
-0.069
-0.174
0.074
The energy barrier for the ring closure from IN1-ZZ
to
(syn)
-1
IN4 is 24.80 kcal.mol . Table 4 shows the main distances,
bond angles and torsion angles for each of the optimized
geometries. Molecular orbital calculated charge densities of
Bond Lengths
formyl(N-phenylimidoyl)ketene IN1-ZZ
show the high-
(syn)
C5-N1
1.288
1.428
1.400
1.096
2.685
3.514
4.080
1.332
1.380
1.432
1.112
2.761
1.914
2.794
1.409
1.311
1.504
1.126
2.965
1.530
2.889
1.349
1.372
1.444
1.447
2.607
1.514
2.808
1.386
1.421
1.404
3.315
0.993
1.487
5.060
est positive charge on C3 (q=0.454 au), so that nucleophilic
attack of negative C11 (-0.123 au) is expected to occur at
C3. The most important factor governing the PyC11 orbital
(or PyC12) of the phenyl group is electron donation from
this group into the ketene C3 atom (PyC3), which has a
large coefficient at the central ketene C atom to which the
attack takes place, resulting in the pyramidalization of C11.
The value of valence angle of C10-C11-H13 at TS4 is
N1-C10
C10-C11
C11-H13
N1-H13
C3-C11
O7-H13
Bond Angles
C10-C11-H13
C4-C3-C11
O7-C3-C4
120.70
92.41
177.69
116.03 105.95 100.54
107.43 115.08 115.73 115.65
142.59 122.90 129.62 122.68
3
116.03° and at IN4 is close to that of bonds in sp hybridized
carbon (105.95°). It can be clearly seen that there is a loss of
the phenyl nodal plane and a partial loss of aromaticity in
phenyl both in structures TS4 and IN4. When the IN1-
Torsion Angles
C5-N1-C10-C11
N1-C10-C11-H13 80.75
C11-C3-C4-C5
C10-C11-C3-C4
N1-C10-C11-C13 5.42
-93.82
-32.46
48.01
6.15
-34.40
-90.62
-5.58
5.93
8.82
2.59
23.64
17.07
-27.94
-46.61
29.18
55.26
-55.80
-45.44
ZZ
is being transformed into its transition state, TS4, the
20.28
-59.90
(syn)
-1.41
C3-C11 bond length decreases. One of the major outcomes
of this strong interaction of C3 with phenyl is that the carbon
atom C11 of benzene which is closest to the C3 atom
becomes highly nucleophilic at TS4. This is clearly demon-
strated in Table 4 where in the partial charges of selected
atoms are given (-0.315 au for C11 and 0.493 au for C3).
The torsion angle of N1-C10-C11-H13 (48.01°) clearly
shows that the atoms are not coplanar.
IN-ZZ
to P1 are normal pericyclic reactions. The IN4
(syn)
is a true minimal energy structure (all positive vibrational
frequencies), while TS4 and TS5 each have one imaginary
frequency. The hydrogen migration in the transition state
TS5 is supported by the analysis of motion along the imag-
inary vibrational mode. This mode's frequency is very
The small computed energy of IN4 confirms our hypoth-
esis that the donor-acceptor interaction between the π elec-
trons of phenyl groups and the vacant carbon p orbital of
-1
large, 1600.44 cm , and the corresponding reduced mass
of 0.983 amu is very close to that of the hydrogen atom.
The structure of the transition state TS5 corresponds to the
H13 atom inserting into the C5=N1 bond and involves pri-
marily hydrogen migration from C11. The reacting atoms
approach cause the C11-H13 bond length to increase and
C5=N1 double bond to be weaken. The transition state TS5
is characterized by the presence of a four membered cycle.
For TS5, the bond distances N1-C10, C10-C11 and C11-
H13 are 1.372, 1.444 and 1.447 Å, respectively (see Table
4). Bond length of H13 to N1 and O7 at the TS5 are 2.607
and 2.808 Å, respectively. As H13 lies directly over the π
cloud of the ring, H13 shifts on to N1 not on to O7. The cal-
culated heat of formation of enol structure P2 were com-
pared with that of keto structure P1, which is slightly more
stable than the enol form P2.
the ketene LUMO is the key factor in stabilizing the IN4
-1
(∆H =2.00 kcal.mol ). The electrocyclization reaction of
rel
EXPERIMENTAL
Solvents were dried by refluxing the appropriate drying agent
and distilled before use. Melting points were determined on the
Electrothermal 9200 apparatus and are uncorrected.
Figure 4: Atom-numbering scheme and structures for IN-ZZ
TS4, TS5, P1, P2 and P3.. Two side views, rotated by approximately 90 ,
,, IN4),
(syn)
o
are given for IN-ZZ
,, TS4, IN4 and.TS5.
(syn)

794
E. Sarıpınar and S. Karatas¸
Vol. 42
Microanalyses were performed on a Carlo Erba Elemental
Analyser Model 1108; the results agreed favourably with the cal-
culated values. IR spectra were recorded on a Shimadzu Model
Anal. Calcd. for C H NO : C, 73.06; H, 4.95; N, 3.28.
26 21 5
Found: C, 73.25; H, 4.86; N, 3.30.
4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-1-(1-naphtyl)-2,3-
dihydro-1H-pyrrole-2,3-dione (3d).
1
435 V-04 spectrometer, using potassium bromide discs. H and
13
C NMR spectra were recorded on Varian 4200 Gemini spec-
1 g (2.96 mmol) of 1 and 0.68 g (2.96 mmol) N-(benzyli-
dene)naphthalen-1-amine benzylidene-1-naphtyl amine 2d yield
0.96 g (70 %) of 9d (reaction time and temperature 48h, 65-70
°C), mp 209-210 °C (toluene); ir (KBr): ν=1760, 1710, 1640
trometer. The chemical shifts are reported in ppm from tetram-
ethylsilane and given in δ units. All experiments were followed
by tlc using DC Alufolien kieselgel 60 F
Model Camag tlc lamp (254/366 nm).
Merck and with a
254
…
…
-1
(C=O), 1600-1460 cm (C C and C N, aromatic rings),
Synthesis of the 2,3-Dihydro-1H-pyrole-2,3-diones (3a).
-1
1
1360 (O-CH ), 1300 (C-N), 1240, 1080 cm (C-O-C ν , ν ); H
3
as
s
General Procedures.
nmr (CDCl ): δ=7.94-6.53 (m, 15H, Ar-H), 3.87 (s, 3H, -OCH ),
3
3
13
3.65 (s, 3H, OCH ) ppm; C nmr (CDCl ): δ=189.51 (t, j=4.2
3
3
Appropriate amounts of 4-(-4-methoxybenzoyl)-5-(-4-methoxy-
phenyl)-2,3-dihydro-1H-2,3-furandione 1 and the corresponding
Schiff bases 2a-f were mixed and allowed to react for 48-96 h at
60-70 °C in an oven. The red crude product formed was triturated
with dry ether, collected by filtration and recrystallized from a suit-
Hz, ArCO), 180.56 (s, C =O), 175.87 (t, j=3.5 Hz, C-5), 166.11
3
(s, C-10), 165.25 (s, C-17), 160.64 (s, C =O), 115.61 (s, C-4),
2
136.34-115.14 (m, aromatic C's), 57.50, 57.30 (two s, j = 145.7
Hz, 2 x OCH ).
3
Anal. Calcd. for C
H NO : C, 75.15; H, 4.57; N, 3.02.
29 21 5
able solvent and dried on P O .
2
5
Found: C, 75.16; H, 4.31; N, 3.04.
4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-1-phenyl-2,3-dihy-
dro-1H-pyrrole-2,3-dione (3a).
1,2-Bis[4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-dihy-
dro-1H-pyrrole-2,3-dione-1-yl]ethane (3e).
1 g (2.96 mmol) of 1 and 0.54 g (2.96 mmol) N-benzylidene ani-
line 2a yield 1.02 g (83 %) of 3a (reaction time and temperature 48
h, 60 °C), mp 182 °C (xylene); ir (KBr): ν=1750, 1710, 1640
1 g (2.96 mmol) of 1 and 0.35 g (1.48 mmol) N,N'-bis(benzyli-
dene)ethane-1,2-diamine 1,2-dibenzylidene ethylenediamine 2e
yield 1.66 g (80 %) of 9e (reaction time and temperature 96h, 60
°C), mp 148-150 °C (chloroform/n-hexane); ir (KBr): ν=1750,
…
…
(C=O), 1600-1480 (C C and C N, aromatic rings), 1360 (O-
-1
1
CH ), 1300 (C-N), 1240, 1060 cm (C-O-C ν , ν ); H nmr
3
as
s
…
1720, 1700, 1650, 1640 (C=O groups), 1600-1480 (C C and
(DMSO-d ): δ=7.97-6.74 (m, 13H, Ar-H), 3.84 (s, 3H, OCH ), 3.69
6
3
…
C
N, aromatic rings), 1370 (O-CH ), 1320 (C-N), 1250, 1040
13
3
ppm (s, 3H, OCH ); C nmr (DMSO-d ): δ=187.79 (t, j=3.7 Hz,
3
6
-1
1
cm (C-O-C ν , ν ); H nmr (CDCl ): δ=7.75-6.55 (m, 16H, Ar-
as
s
3
ArCO), 179.28 (s, C =O), 172.02 (s, C-5), 163.69 (s, C-10), 163.12
3
H), 3.80-3.77 (12H, 4 x OCH ), 3.70-3.55 (4H, NCH CH N)
3
2
2
(s, C-17), 162.30 (s, C =O), 158.45 (s, C-21), 113.91 (s, C-4),
2
13
ppm; C nmr (CDCl ): δ = 188.67 (t, j=3.8 Hz, 2 x ArCO),
3
136.08-112.67 (m, aromatic C's), 55.85, 55.68 (two s, 2 x OCH ).
3
180.62 (s, C-3 and C-3'), 175.03 (t, j=4.4 Hz, C-5 and C-5'),
165.98 (d, C-10 and C-10'), 165.06 (s, C-17 and C-17'), 160.92
(s, C-2 and C-2'), 120.63 (s, C-4 and C-4'), 134.02-115.00 (m,
Anal. Calcd. for C
H NO : C, 72.63; H, 4.63; N, 3.39.
25 19 5
Found: C, 72.90; H, 4.65; N, 3.33.
4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-1-(2-methyl-
phenyl)-2,3-dihydro-1H-pyrrole-2,3-dione (3b).
aromatic C's), 57.44, 57.17 (two d, j = 145.7 Hz, 4 x OCH ),
3
41.77 (s, -CH CH -).
2
2
Anal. Calcd. for C
Found: C, 68.27; H, 4.45; N, 4.21.
H N O : C, 68.57; H, 4.60; N, 4.00.
40 32 2 10
1 g (2.96 mmol) of 1 and 0.58 g (2.96 mmol) N-(benzylidene)-2-
methylaniline 2b afford 1.07 g (85 %) of 3b (reaction time and tem-
perature 48 h, 65-70 °C), mp 232-233°C (xylene); ir (KBr):
1,4-Bis[4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-dihy-
dro-1H-pyrrole-2,3-dione-1-yl]benzene (3f).
…
…
-1
ν=1750, 1710, 1640 (C=O), 1605-1480 cm (C C and C N,
1
aromatic rings); H nmr (CDCl ): δ=7.88-6.66 (m, 12H, Ar-H),
3
1 g (2.96 mmol) of 1 and 0.42 g (1.48 mmol) N,N'-bis(benzyli-
dene)benzene-1,4-diamine 2f yield 1.77 g (80 %) of 9f (reaction
time and temperature 96 h, 60 °C), mp 152 °C (chloroform/n-
hexane); ir (KBr): ν=1770, 1720, 1700, 1650, 1640 (C=O
3.86 (s, 3H, OCH ), 3.73 (s, 3H, OCH ), 2.25 ppm (s, 3H, CH );
3
3
3
13
C nmr (CDCl ): δ=189.46 (t, j=3.8 Hz, ArCO), 180.58 (s, C =O),
3
3
175.29 (t, j=4.3 Hz, C-5), 166.07 (s, C-10), 165.27 (s, C-17), 160,01
(s, C =O), 134.80 (s, C-21), 115.76 (s, C-4), 138.35-114.65 (m,
2
…
…
-1
groups), 1600-1480 (C C and C N, aromatic rings), 1360
Aromatic C's), 57.49, 57.38 (s, 2 x OCH ), 20.13 (s, CH ).
3
3
1
(O-CH ), 1310 (C-N), 1250, 1050 cm (C-O-C ν , ν ); H nmr
3
as
s
Anal. Calcd. for C
H NO : C, 73.06; H, 4.95; N, 3.28.
26 21 5
(CDCl ): δ=8.01-6.60 (m, 20H, Ar-H), 3.83-3.62 (b, 12H, 4 x
3
Found: C, 72.95; H, 4.88; N, 3.49.
13
OCH ) ppm; C nmr (CDCl ): δ=189.39 (t, j=4.2 Hz, 2 x
3
3
4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-1-(4-methyl-
phenyl)-2,3-dihydro-1H-pyrrole-2,3-dione (3c).
ArCO), 180.34 (s, C-3 and C-3'), 173.42 (t, j=4.5 Hz, C-5 and C-
5'), 166.47 (d, C-10 and C-10'), 165.39 (s, C-17 and C-17'),
160.11 (s, C-2 and C-2'), 120.77 (s, C-4 and C-4'), 135.05-115.05
1 g (2.96 mmol) of 1 and 0.58 g (2.96 mmol) N-(benzylidene)-
4-methylaniline 2c yield 1.05 g (83 %) of 3c (reaction time and
temperature 48h, 60 °C), mp 180 °C (toluene); ir (KBr): ν=1755,
(m, aromatic C's), 57.48, 57.20 (two d, j = 145.7 Hz, 4xOCH ).
3
Anal. Calcd. for C
H N O : C, 70.58; H, 4.31; N, 3.74.
44 32 2 10
…
…
Found: C, 70.31; H, 4.58; N, 4.01.
-1
1705, 1640 (C=O), 1600-1460 cm (C C and C N, aromatic
1
rings); H nmr (CDCl ): δ=7.84-6.66 (m, 12H, Ar-H), 3.83 (s,
3H, OCH ), 3.73 (s, 3H, OCH ), 2.32 (s, 3H, CH ) ppm; C nmr
Thermolysis of the 2,3-Dihydro-1H-pyrole-2,3-diones 3a-d and
Synthesis of the 1H-Quinolin-4-ones (5a-d).
3
13
3
3
3
(CDCl ): δ=189.46 (t, j=4.0 Hz, ArCO), 180.54 (s, C =O),
3
3
General Procedures.
174.65 (t, j=4.4 Hz, C-5), 166.02 (s, C-10), 165.16 (s, C-17),
160.23 (s, C =O), 115.73 (s, C-4), 140.40-114.82 (m, aromatic
Approximately 10 min. heating on an oil-bath of 2,3-dihy-
2
C's), 57.49, 57.41 (two s, 2 x OCH ), 23.09 (s, CH ).
dro-1H-pyrole-2,3-diones 3a-d (1 g, equivalent mol) at 240-
3
3

Jul-Aug 2005
Synthesis and Thermolysis of the 2,3-dihydro-1H-pyrole-2,3-diones
795
250 °C led to a crude product, which was treated with ether
and recrystallized from n-butanol and left to dry on P O to
Anal. Calcd. for C H NO : C, 77.23; H, 4.86; N, 3.22.
28 21 4
Found: C, 76.98; H, 4.73; N, 3.20.
2
5
give 5a-d (40-52 %).
Acknowledgements.
3-(4-methoxybenzoyl)-2-(4-methoxyphenyl)quinolin-4(1H)-one
(5a).
The authors wish to express to their gratitude to Dr. Yunus
Akçamur, Dr. ·aban Patat and Ars¸. Gör. Dilek Ünal for helpful
and encouraging discussions. This project was financially sup-
ported by the Science and Technical Research Council of turkey
This compound was obtained by the general procedure as
white solid, mp 262 °C, yield 0.42 g (45%); ir (KBr): ν=3360 (b,
N-H), 1670, 1630 (C=O), 1600-1450 (C C and C N, aro-
matic rings), 1360 (O-CH ), 1300 cm (C-N); H nmr (DMSO-
…
…
·
(TÜBITAK, project no:TBAG-AY/354(104T012)), Resarch
-1
1
·
Center of Erciyes Universty and ARÇELIK Company.
3
d ): δ = 12.01 (br s, 1H, NH), 8.14-6.94 (m, 12H, Ar-H), 3.81,
6
13
3.76 (6H, 2 x OCH ); C nmr (DMSO-d ): δ=195.96 (t, j=3.8
3
6
REFERENCES AND NOTES
Hz, ArCO), 176.84 (d, j=2 Hz, C-4), 164.83 (s, C-15), 162.31 (s,
C-22), 150.47 (t, j=4.1 Hz, C-2), 141.74 (s, C-8a), 127.71 (s, C-
4a), 133.96-115.71 (m, aromatic C's), 115.60 (s, C-3), 57.26,
57.10 (s, j=145.7 Hz, 2 x OCH ).
Anal. Calcd. for C
*
To whom correspondence schould be addressed: e-mail:
emin@erciyes.edu.tr; tel: +90 352 437 49 29; fax: +90 352 437 49 33.
[1a] G. Kollenz, W. Ott, E. Ziegler, K. Peters, H.G. von Schnering,
H. Quast, Liebigs Ann. Chem., 1801 (1980); [b] G. Kollenz, W. Ott, E.
Ziegler, K. Peters, H.G. Schnering, V. Formacek, H. Quast, Liebigs Ann.
Chem., 1137 (1984).
[2a] K. Peters, G. Kollenz, Chem . Ber., 114, 1206 (1981); [b] G.
Kollenz, G. Penn, Dollenz, Y. Akçamur, K. Peters, E-M. Peters, and H. G.
von Schnering, Chem. Ber., 117, 1299 (1984); [c] H. A. El-Nabi, Abd, G.
Kollenz, Monatsh Chem., 128, 381 (1997).
[3a] G. Kollenz, G. Penn, W. Ott, K. Peters, E-M. Peters and H.G.
von Schnering, Chem. Ber., 117, 1310 (1984); [b] W. Heilmayer, C. O.
Kappe, H. Sterk, G. Kollenz, K. Peters, E- M. Peters, H.G. von Schnering
and L. Walz, Chem. Ber., 126, 2061 (1993).
[4] G. Kollenz, G. Penn, W. Ott, K. Peters, E-M. Peters and H.G.
von Schnering, Heterocycles, 26, 625 (1987).
3
H NO : C, 74.79; H, 4.97; N, 3.63.
24 19 4
Found: C, 74.63; H, 4.97; N, 3.48.
3-(4-Methoxybenzoyl)-2-(4-methoxyphenyl)-8-methylquinolin-
4(1H)-one (5b).
This compound was obtained by the general procedure as
white solid, mp 233 °C, yield 0.49 g (52%); ir (KBr): ν=3350 (b,
N-H), 1680, 1635 (C=O), 1600-1450 (C C and C N, aro-
matic rings), 1360 (O-CH ), 1300 cm (C-N); H nmr (CDCl ):
…
…
-1
1
3
3
δ=8.56-6.62 (m, 11H, Ar-H), 3.80, 3.67 (6H, 2 x OCH ), 2.47 (s,
3
13
3H, CH ) ppm; C nmr (CDCl ): δ = 196.17 (t, j=4 Hz, ArCO),
3
3
178.38 (d, j=2.1 Hz, C-4), 165.42 (s, C-15), 163.06 (s, C-22),
150.49 (t, j=3.6 Hz, C-2), 140.06 (s, C-8a), 127.22 (s, C-4a),
135.22-116.36 (m, aromatic C's), 115.62 (s, C-3), 57.36, 57.22 (s,
j=145 Hz, 2 x OCH ), 18.64 (s, CH ).
[5] E. Terpetsching, G. Penn, G. Kollenz, K. Peters, E-M. Peters
and H.G. von Schnering, Tetrahedron, 47, 3045 (1991).
[6a] W. Ott, Synthesis, 478 (1976); [b] W. Ott, E. Terpetsching, H.
Sterk and G. Kollenz, Synthesis, 176 (1987).
[7] G. Kollenz, E. Terpetsching, H. Sterk, K. Peters and E-M.
Peters, Tetrahedron, 55, 2973 (1999).
3
3
Anal. Calcd. for C
Found: C, 74.93; H, 5.29; N, 3.50.
H NO : C, 75.17; H, 5.30; N, 3.51.
25 21 4
3-(4-Methoxybenzoyl)-2-(4-methoxyphenyl)-6-methylquinolin-
4(1H)-one (5c).
[8a] G. Kollenz, H. Sterk and G. Hutter, J. Org. Chem., 56, 235
(1991); [b] W. Heilmayer, H. Sterk and G. Kollenz, Tetrahedron, 54,
8025 (1998).
[9a] W.M. F. Fabian, Acta Chim. Hung., 129, 347 (1992); [b] W.
M. F. Fabian and G. Kollenz, J. Chem. Soc. Perkin Trans 2, 515 (1995);
[c] W. M. F. Fabian and G. Kollenz, J. Org. Chem. 62, 8497 (1997); [d] K.
Bowden, W. M. F. Fabian and G. Kollenz, J. Chem. Soc., Perkin Trans. 2,
547 (1997); [e] W. M. F. Fabian and G. Kollenz, J. Mol. Struct.
(theochem), 187, 199 (1989).
This compound was obtained by the general procedure as light
yellow solid, mp 141 °C, yield 0.37 g (40%); ir (KBr): ν=3350
…
…
(b, N-H), 1680, 1635 (C=O), 1600-1460 (C C and C N, aro-
-1
1
matic rings), 1360 (O-CH ), 1300 cm (C-N); H nmr (CDCl ):
3
3
δ=11.62 (br s, 1H, NH), 7.68-6.38 (m, 11H, Ar-H), 3.74, 3.46 (m,
13
6H, 2 x OCH ), 2.30 (s, 3H, CH ) ppm; C nmr (CDCl ): δ =
3
3
3
[10] [http://www-ang.kfunigraz.ac.at/fabian/echet98/index.htm].
[11a] C. O. Kappe, G. Kollenz and C. Wentrup, J. Chem. Soc., Chem.
Commun., 485 (1992); [b] C. O. Kappe, G. Kollenz, R. Leung-Toung and
C. Wentrup, J. Chem. Soc., Chem. Commun., 487 (1992); [c] C. O. Kappe,
G. Kollenz, R. K. P. Netsch, R. Leung-Toung and C. Wentrup, J. Chem.
Soc., Chem. Commun., 488 (1992); [d] B. Fullon, H. A. A. El-Nabi, G.
Kollenz and C. Wentrup, Tetrahedron Lett., 36, 6547 (1995); [e] B. E.
Fullon and C. Wentrup, J. Org. Chem., 61, 1363 (1996); [f] V. V. R. Rao, B.
E. Fulloon, P. V. Bernhardt, R. Koch and C. Wentrup, J. Org. Chem., 63,
5779 (1998); [g] R. V. V. Rao and C. Wentrup, J. Chem. Soc., Perkin Trans.
1, 2583 (1998); [h] C. Wentrup, V. V. Rammana Rao, W. Frank, B. E.
Fulloon, D. W. j. Moloney and T. Mosandl, J. Org. Chem., 64, 3608 (1999).
[12] D. M. Birney, X. Xu, S. Ham, and X. Huang, J. Org. Chem.,
62, 7114 (1997).
197.34 (t, j=4.2 Hz, ArCO), 178.08 (d, C-4), 165.32 (s, C-15),
162.58 (s, C-22), 151.55 (t, j=3.5 Hz, C-2), 140.15 (s, C-8a),
127.75 (s, C-4a), 135.53-115.67 (m, aromatic C's), 115.50 (s, C-
3), 57.31, 56.88 (two s, 2 x OCH ), 23.08 (s, CH ).
3
3
Anal. Calcd. for C
H NO : C, 75.17; H, 5.30; N, 3.51.
25 21 4
Found: C, 75.04; H, 5.36; N, 3.49.
3-(4-Methoxybenzoyl)-2-(4-methoxyphenyl)benzo[h]quinolin-
4(1H)-one (5d).
This compound was obtained by the general procedure as
white solid, mp 141 °C, yield 0.44 g (47%); ir (KBr): ν=3300 (b,
…
…
N-H), 1670, 1630 (C=O), 1600-1450 (C C and C N, aro-
-1
1
matic rings), 1350 (O-CH ), 1300 cm (C-N); H nmr (CDCl ):
3
3
[13a] C. Wentrup, W. Heilmayer and G. Kollenz, Synthesis, 1219
(1994); [b] T. T. Tidwell, Ketenes. John Wiley and Sons. New York. p
δ=10.51 (br s, 1H, NH), 8.58-6.46 (m, 14H, Ar-H), 3.76, 3.35
13
(two s, 6H, 2 x OCH ) ppm; C nmr (CDCl ): δ=196.20 (t, j=3.8
·
·
3
3
665 (1995); [c] E. Sarıpınar, I. Ö. Ilhan and Y. Akcamur, Heterocycles,
57, 1445 (2002).
Hz, ArCO), 177.92 (d, C-4), 165.31 (s, C-15), 162.53 (s, C-22),
150.42 (t, j=3.6 Hz, C-2), 138.83 (s, C-8a), 127.70 (s, C-4a),
136.97-115.72 (m, aromatic C's), 115.46 (s, C-3), 57.30, 56.77
[14] J. J. P. Stewart, J. Comp. Chem., 10, 209 (1989).
[15] PC Spartan Pro, Wavefunction, Inc.; Irvine, California,
(1999).
(two s, 2 x OCH ).
3

796
E. Sarıpınar and S. Karatas¸
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·
·
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