Chemical transformations of reaction products of 2-methyl-3-(4-tolyl)-4(3H) -quinazolone with benzil and its 4,4′-derivatives

Article abstract of DOI:10.1007/s11172-007-0025-0

The reaction of 2-methyl-3-(4-tolyl)-4(3H)-quinazolone with benzil produces 2-[(Z)-3-oxo-2,3-diphenylprop-1-enyl]-3-(4-tolyl)-4(3H)-quinazolone, which is readily transformed into 2-(3,3-diphenylsuccinimido)-N-(4-tolyl)benzamide on dissolution in organic water-containing solvents. The rearrangement mechanism was suggested and investigated by the quantum chemical PM3 method. Springer Science+Business Media, Inc. 2007.

Full text of DOI:10.1007/s11172-007-0025-0

Russian Chemical Bulletin, International Edition, Vol. 56, No. 1, pp. 154—159, January, 2007
154
Chemical transformations of reaction products of 2ꢀmethylꢀ3ꢀ(4ꢀtolyl)ꢀ
4(3H )ꢀquinazolone with benzil and its 4,4´ꢀderivatives
I. I. Ponomarev, D. Yu. Razorenov,ꢀ D. S. Perekalin, P. V. Petrovskii, and Z. A. Starikova
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5085. Eꢀmail: razar@ineos.ac.ru
The reaction of 2ꢀmethylꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone with benzil produces
2ꢀ[(Z )ꢀ3ꢀoxoꢀ2,3ꢀdiphenylpropꢀ1ꢀenyl]ꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone, which is readily transꢀ
formed into 2ꢀ(3,3ꢀdiphenylsuccinimido)ꢀNꢀ(4ꢀtolyl)benzamide on dissolution in organic waꢀ
terꢀcontaining solvents. The rearrangement mechanism was suggested and investigated by the
quantum chemical PM3 method.
Key words: 3ꢀarylꢀ2ꢀmethylꢀ4(3H )ꢀquinazolones, αꢀdiketones, 2ꢀ[(Z )ꢀ2,3ꢀdiarylꢀ3ꢀ
oxopropꢀ1ꢀenyl]ꢀ4(3H )ꢀquinazolones, 2,2ꢀdiarylsuccinimides, quantum chemical calculations.
Scheme 1
Quinazoloneꢀbased polymeric materials have attracted
attention due to a combination of luminescent properties,
high thermal stability, heat resistance, and wide possibiliꢀ
ties of the molecular design.1 In these objects, the optical
properties occur not as a result of the presence of an
additional dye, which is either bound to the polymer or
introduced into the material, but are caused by the chroꢀ
mophoric system of the polymer. At the same time, it is
necessary to search for new ways of modifying a chroꢀ
mophoric system and study in more detail the reactions
for the construction of polymers with desired chemiꢀ
cal structures with the use of model monomeric comꢀ
pounds.
Earlier, polyquinazolones containing arylenevinylene
side groups have been synthesized2 in pentafluorophenol
(PFP), and a series of model compounds and polymers
based on 3ꢀaminoꢀ2ꢀmethylquinazolones and αꢀdiketones
have been prepared.3 When synthesizing new model comꢀ
pounds, it was found that the reaction products of some
2ꢀmethylquinazolones with αꢀdiketones have a property
unusual for their structures, i.e., their fluorescence is subꢀ
stantially increased in the presence of acids.4 Because to
this behavior, such compounds have attracted interest. In
this connection, we decided to study these compounds
more thoroughly.
One example is the reaction product of 2ꢀmethylꢀ3ꢀ
(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (1) with benzil in PFP
(Scheme 1). It was found that the reaction produces
2ꢀ[(Z )ꢀ3ꢀoxoꢀ2,3ꢀdiphenylpropꢀ1ꢀenyl]ꢀ3ꢀ(4ꢀtolyl)ꢀ
4(3H )ꢀquinazolone (2) as the major product. We failed to
unambiguously prove the presence of the possible E isoꢀ
mer in the reaction mixture. However, it is known2 that
these reactions can produce two isomers.
The structure of compound Zꢀ2 was established by
Xꢀray diffraction study of single crystals grown by vacuum
sublimation (Fig. 1).
As mentioned above, the fluorescent properties of
compound 2 and other reaction products of 2ꢀalkylꢀ
quinazolones with aromatic αꢀdiketones are substantially
changed in the presence of acids. This behavior could be
attributed to certain changes in the threeꢀdimensional
molecular structures upon protonation, the electron denꢀ
sity redistribution, and an increase in the degree of conjuꢀ
gation of the π system. With the aim of more reliably
evaluating these changes, we performed an Xꢀray diffracꢀ
tion study of crystals of compound 2 grown in 85% formic
acid. It appeared that the structure of crystalline 2ꢀ(3,3ꢀdiꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 146—151, January, 2007.
1066ꢀ5285/07/5601ꢀ0154 © 2007 Springer Science+Business Media, Inc.

Transformation of quinazolones into succinimides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 1, January, 2007
155
terestingly, the identical
spectrum was obtained for a
solution of the starting quinꢀ
azolone 2 in DMSOꢀd6.
Compound 2 is poorly
soluble in DMSOꢀd6 at
room temperature, whereas
heating of compound 2 in a
tube for the purpose of disꢀ
solving 2 led to its rearrangement. Since DMSOꢀd6 genꢀ
erally contains water in an amount sufficient for hydrolyꢀ
sis of the quinazolone ring, compound 2 is finally comꢀ
pletely transformed into product 3. Therefore, it was imꢀ
possible to record the 1H NMR spectrum of compound 2.
It was found that this transformation also readily occurs
in other organic solvents containing small amounts of
water, for example, in ethanol.
C(20)
C(21)
O(1)
C(13)
C(12)
C(19)
C(14)
C(11)
C(10)
C(17)
C(22)
C(15)
C(16)
C(18)
C(23)
N(1)
C(4)
C(9)
C(8)
C(5)
C(8A)
C(2)
N(3)
C(7)
C(6)
C(25)
C(4A)
C(24)
C(26)
C(27)
C(29)
O(2)
C(28)
C(30)
Fig. 1. Molecular structure of 2ꢀ[(Z )ꢀ3ꢀoxoꢀ2,3ꢀdiphenylpropꢀ
1ꢀenyl]ꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (2).
In addition to compound 2, we studied the reaction
products of 4,4´ꢀdisubstituted derivatives of benzil with
2ꢀmethylꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (1).
phenylsuccinimido)ꢀNꢀ(4ꢀtolyl)benzamide (3) is substanꢀ
tially different from that of the starting compound (Fig. 2).
The Xꢀray diffraction study showed that the quinꢀ
azolone ring is absent in molecule 3, but the latter conꢀ
tains the new fiveꢀmembered succinimide fragment. In
addition, the phenyl substituents, which are bound to
different carbon atoms in the starting compound, are
bound to the same carbon atom in compound 3. Reaction
It appeared that dibromoꢀsubstituted compound 4 beꢀ
haves similarly to unsubstituted analog 2 and is readily
transformed into rearrangement product 6 on dissolution
in DMSOꢀd6 and heating (Scheme 2). As in the case of
compound 2, this substantially hinders the measurement
of the 1H NMR spectrum of unrearranged compound 4.
Scheme 2
1
product 3 was characterized by H NMR spectroscopy,
which additionally confirmed its chemical structure. Inꢀ
C(18)
C(14)
C(13)
C(15)
C(16)
C(12)
C(17)
H(2A)
C(11)
N(2)
O(3)
C(29)
C(28)
C(27)
C(30)
C(25)
C(9)
O(1)
C(1)
C(10)
C(5)
N(1)
C(26)
C(8)
C(7)
C(2)
C(19)
C(3)
C(20)
C(4)
C(6)
O(2)
C(24)
C(21)
C(22)
C(23)
X = Br (4, 6), F (5, 7)
The structure of difluoroꢀsubstituted compound 5 was
established by Xꢀray diffraction study of crystals grown
Fig. 2. Molecular structure of the rearrangement product,
Nꢀ(4ꢀtolyl)ꢀ2ꢀ(3,3ꢀdiphenylsuccinimido)benzamide (3).

156
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 1, January, 2007
Ponomarev et al.
F(1)
study of the structures of all possible intermediates A—F
and the transition state of the key reaction step, viz., the
rearrangement C → D. The geometry calculations were
carried out by the semiempirical PM3 method for the
model compound with R = Me and X = H. The energies
of the structures were estimated by the B3LYP/6ꢀ31G*
method. The optimized geometry of the molecules A and F
agrees well with the Xꢀray diffraction data for compounds 2
and 3, respectively (the bond length deviations are at
most 0.009 Å). This confirms the applicability of the
PM3 calculation method and the validity of the replaceꢀ
ment of R = Ar with R = Me.
C(14)
C(15)
C(16)
C(17)
C(13)
C(12)
O(1)
C(20)
C(19)
F(2)
C(11)
C(21)
C(22)
C(8)
C(8A)
C(7)
C(10)
C(18)
N(1)
C(23)
C(9)
C(2)
C(6)
C(25)
C(5)
C(4A)
N(3)
C(24)
C(29)
C(4)
O(2)
C(26)
C(27)
C(28)
Protonation of the starting molecule A can afford the
following three cations: Bꢀ1, Bꢀ2, and Bꢀ3. However, it
was demonstrated that the optimization leads to the
C(30)
Fig. 3. Molecular structure of 2ꢀ[(Z )ꢀ3ꢀoxoꢀ2,3ꢀbis(4ꢀfluoroꢀ
phenyl)propꢀ1ꢀenyl]ꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (5).
from dioxane (Fig. 3). It should be noted that this comꢀ
pound is more stable. We succeeded in measuring the
1H NMR spectrum adequate for the chemical structure
only for this compound (unlike related compounds 2
and 4). The spectrum shows no signals of the CH2 group
of the succinimide fragment and the amide group, which
are characteristic of the rearrangement products, and has
a narrow singlet for the proton at the acyclic double bond.
The rearrangement of compound 5 is hindered, but it can
be performed under more drastic conditions (refluxing in
C(3)
C(1)
C(2)
O(1)
1
85% formic acid for ~100 h). The H NMR spectrum of
transformation product 7 is similar to that of compound 6.
Compounds 5 and 7 were additionally characterized by
19F NMR spectroscopy.
The mechanism of the aboveꢀdescribed transformaꢀ
tions can be represented as follows (Scheme 3).
Fig. 4. Structure of the transition state of the rearrangement
C → D. Bond lengths/Å: C(1)—C(2), 1.486; C(1)—C(3), 1.811;
C(2)—C(3), 1.843; C(2)—O(1), 1.351.
The rearrangement starts with reversible protonation
of the starting compound A at the carbonyl oxygen atom
at position 4 of the quinazolone ring (Bꢀ1), at the nitroꢀ
gen atom at position 1 of the quinazolone ring (Bꢀ2), or at
the carbonyl oxygen atom of the benzoyl fragment (Bꢀ3).
In the protonated form Bꢀ3, the fiveꢀmembered ring is
reversibly closed to give the intermediate C. In our opinꢀ
ion, it is the presence of the intermediate product C that
explains the characteristic increase in fluorescence of comꢀ
pounds 2, 4, and 5 in the presence of acids. The further
transformation C → D can occur only through the transꢀ
fer of the phenyl fragment, which was observed in rearꢀ
rangements described in the literature.5,6 The transforꢀ
mation D → E is apparently tautomeric, the proton being
transferred from the carbonyl group to the =CH— fragꢀ
ment in the ring. Finally, the quinazolone ring undergoes
hydrolysis to form the product F.
E/kcal mol–1
D
37.21
Bꢀ1
C
Bꢀ2
11.09
E
Reaction coordinate
To describe the mechanism in more detail and conꢀ
firm its validity, we performed the quantum chemical
Fig. 5. Energy profile of the transformation C → E for the reacꢀ
tion A + H2O → F.

Transformation of quinazolones into succinimides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 1, January, 2007
157
Scheme 3
barrierless transformation of the structure Bꢀ3 into the
cyclic form C, which is substantially more stable than Bꢀ1
(by 15.64 kcal mol–1) and is only slightly less stable
than Bꢀ2 (by 3.75 kcal mol–1). The further rearrangement
C → D proceeds through the ipsoꢀtype transition state
(Fig. 4), whose energy is 37.21 kcal mol–1 higher than
that of the structure C, and this transition state deterꢀ
mines the overall reaction rate. The rather high activation
energy is apparently attributed to the fact that the calculaꢀ
tions ignore the solvation effects, which can substantially
influence stability of cationic species in a polar medium.
The intermediate D is 25.79 kcal mol–1 less stable
than C. However, it can undergo a tautomeric transforꢀ
mation into the cation E, which is 11.09 kcal mol–1 more
stable than C. In a polar medium, the activation barrier
for this tautomerization is insignificant (presumably, is
lower than 5 kcal mol–1). The resulting overall reaction
profile is shown in Fig. 5.
The calculated total thermal effect of the reaction
A + H2O → F is 24.66 kcal mol–1
.
Therefore, the experimental data and the results of
quantum chemical calculations obtained in the present
study suggest that the observed rearrangement can occur
by the aboveꢀdescribed mechanism. It remains unclear
how the substituents X influence the rearrangement rate.
Presumably, in the case of X = F, protonation of the
carbonyl oxygen atom of the benzoyl fragment (A → Bꢀ3)
is less favorable, which hinders further transformations.

158
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 1, January, 2007
Ponomarev et al.
precipitate of the acetamidinium salt that formed was filtered
off, dried in air, and added with stirring to a 0.5% aqueous
NaOH solution (20 mL). The suspension was stirred for 4 h. The
precipitate was filtered off, washed with water to neutral pH,
and dried. The yield was 1.75 g (70%), m.p. 151—152 °C (cf. lit.
Experimental and calculation procedure
The melting points were determined on a Boetius hotꢀstage
1
apparatus and are uncorrected. The H and 19F NMR spectra
were recorded on Bruker AMXꢀ400 (400.13 MHz) and Bruker
AVꢀ300 (282.40 MHz) instruments in DMSOꢀd6; δ were calcuꢀ
lated relative to the residual signals for the protons of the deuterꢀ
ated solvent as the internal standard (1H) and CFCl3 as the
external standard (19F). The course of the reactions was moniꢀ
tored and the purities of the reaction products were checked by
TLC on Silufol UVꢀ254 plates (toluene—acetone, 2 : 1, as the
eluent). Compounds 2, 4, and 5 were visualized by placing the
eluted and dried chromatograms in a vessel with CF3COOH
vapor, after which an increase in the fluorescence intensity of
their spots was observed in UV light (λ = 365 nm). Pentaꢀ
fluorophenol and anthranilic acid (Aldrich) were used without
additional purification.
1
data8: m.p. 151—152 °C), Rf 0.6. H NMR, δ: 2.13 and 2.40
(both s, 3 H each, C6H4Me, 2ꢀMe); 7.29 and 7.36 (both d,
2 H each, C6H4, J = 8.0 Hz); 7.49 (t, 1 H, H(4), J = 7.5 Hz);
7.65 (d, 1 H, H(3), J = 8.1 Hz); 7.82 (t, 1 H, H(2), J = 7.4 Hz);
8.09 (d, 1 H, H(1), J = 7.8 Hz).
2ꢀ[(Z )ꢀ3ꢀOxoꢀ2,3ꢀdiphenylpropꢀ1ꢀenyl]ꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀ
quinazolone (2). Compound 1 (0.25 g, 1 mmol) and benzil (0.21 g,
1 mmol) were heated in PFP (0.5 g) at 140 °C for 40 h. The
reaction mixture was precipitated with ethanol (10 mL). The
yellow precipitate that formed was filtered off and washed with
cold ethanol. The yield was 0.18 g (40%), m.p. 200—210 °C,
Rf 0.7 (fluorescent spot). Found (%): C, 81.39; H, 5.11; N, 6.28.
C30H22N2O2. Calculated (%): C, 81.43; H, 5.01; N, 6.33.
2ꢀ(3,3ꢀDiphenylsuccinimido)ꢀNꢀ(4ꢀtolyl)benzamide (3).
Compound 2 (0.10 g, 0.218 mmol) was refluxed in a waꢀ
ter—ethanol mixture (1 : 1, v/v, 10 mL) for 2 h and then cooled.
The white precipitate that formed was filtered off. The yield was
0.09 g (86%), m.p. 220—225 °C, Rf 0.6 (the spot shows no fluoꢀ
rescence). Found (%): C, 78.26; H, 5.23; N, 6.10. C30H24N2O3.
Calculated (%): C, 78.24; H, 5.25; N, 6.08. 1H NMR, δ: 2.30 (s,
2ꢀMethylꢀ4Hꢀ3,1ꢀbenzoxazinꢀ4ꢀone. Anthranilic acid (8 g,
58 mmol) was refluxed in Ac2O (20 mL) for 4 h using a calcium
chloride tube. Excess Ac2O was distilled off, and the resulting
crystals were sublimed at 75—100 °C (0.01 Torr). The yield was
8.30 g (88%), m.p. 80—82 °C (cf. lit. data7: m.p. 86—87 °C).
2ꢀMethylꢀ3ꢀ(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (1). 2ꢀMethylꢀ4Hꢀ
3,1ꢀbenzoxazinꢀ4ꢀone (1.61 g, 10 mmol) and pꢀtoluidine (1.07 g,
10 mmol) were stirred in Et2O (20 mL) for 8 h. The white
Table 1. Crystallographic data and the refinement statistics for compounds 2, 3, and 5
Parameter
Molecular formula
2
3
5
C
30H22N2O2
442.50
P21/n
C30H24N2O3
C30H20F2N2O2
478.48
M
460.51
P21/c
Space group
P21/c
T/K
120
173
193
a/Å
b/Å
c/Å
10.609(1)
10.824(1)
20.603(3)
104.847(3)
2286.9(5)
4
19.076(6)
7.392(3)
16.974(6)
104.45(3)
2318(1)
4
11.704(2)
18.497(4)
11.040(2)
106.06(3)
2296.7(8)
4
β/deg
V/Å3
Z
dcalc/g cm–3
Crystal color and shape
Crystal dimensions/mm
Diffractometer
µ/cm–1
1.285
1.320
1.384
Colorless prisms
0.35×0.30×0.25
«SMART Bruker»
0.81
Colorless plates
0.50×0.45×0.30
0.25×0.20×0.15
«Syntex P21»
0.86
θ/2θ
0.98
ω
Scanning mode
φ/ω
2θmax/deg
58.0
52.0
48.0
Number of reflections
Number of independent
17051
5942
(0.0489)
0.0562
(2934)
4388
4108
3707
3516
(0.129)
0.0829
(1165)
0.1537
290
reflections (Rint
)
(0.0326)
0.0615
(2831)
0.1319
316
R1 (based on F for reflections
with I > 2σ(I ))
wR2 (based on F 2 for all reflections)
0.1134
307
Number of parameters
in refinement
Weighting scheme
P
–1 = σ (Fo2) + (aP)2 + bP
2
w
1/3(Fo2 + 2Fc )
2
a
b
0.0259
0.5000
1.005
928
0.0137
4.4615
1.001
968
0.0000
0.0000
0.867
992
GOOF
F(000)

Transformation of quinazolones into succinimides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 1, January, 2007
159
3 H, C6H4Me); 3.50 and 3.86 (both d, 1 H each, CH2 of the
succinimide fragment, J = 18.6 Hz); 7.14—7.82 (m, 18 H,
H arom.); 10.47 (s, 1 H, NH).
Quantum chemical calculations were performed with the use
of the Gaussian 98 program package (version A.7).10 The geomꢀ
etry of the species A—F was calculated by the semiempirical
PM3 method. The transition state of the rearrangement C → D
was found using the QST2 algorithm according to the same
method. The energies of the structures were evaluated
by the B3LYP/6ꢀ31G* method. The results of calculations
were visualized using the ChemCraft program, version 1.5
(www.chemcraftprog.com).
2ꢀ[(Z )ꢀ2,3ꢀBis(4ꢀbromophenyl)ꢀ3ꢀoxopropꢀ1ꢀenyl]ꢀ3ꢀ
(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (4). Compound 1 (0.25 g, 1 mmol)
and 4,4´ꢀdibromobenzil (0.37 g, 1 mmol) were heated in PFP
(0.6 g) at 140 °C for 40 h. The reaction mixture was precipitated
with ethanol (20 mL), unconsumed 4,4´ꢀdibromobenzil (0.26 g)
was filtered off, the mother liquor was concentrated, isopropanol
(10 mL) was added, and the precipitate was filtered off. The yield
was 0.12 g (20%), m.p. 185—210 °C, Rf 0.7 (fluorescent spot).
Found (%): C, 59.97; H, 3.37; Br, 26.55; N, 4.62. C30H20Br2N2O2.
Calculated (%): C, 60.02; H, 3.36; Br, 26.62; N, 4.67.
We thank E. I. Goryunov for continuous support and
valuable advice.
2ꢀ[(Z )ꢀ3ꢀOxoꢀ2,3ꢀbis(4ꢀfluorophenyl)propꢀ1ꢀenyl]ꢀ3ꢀ
(4ꢀtolyl)ꢀ4(3H )ꢀquinazolone (5). Compound 1 (0.25 g, 1 mmol)
and 4,4´ꢀdifluorobenzil (0.25 g, 1 mmol) were heated in PFP
(0.5 g) at 140 °C for 40 h. The reaction mixture was precipitated
with ethanol (10 mL), and the yellow precipitate that formed
was filtered off. The yield was 0.24 g (50%), m.p. 230—232 °C,
References
1. V. N. Odnoralova and E. A. Vasil´evaꢀSokolova, in Itogi nauki
i tekhniki. Ser. Khimiya i tekhnologiya vysokomolekulyarnykh
soedinenii [Advances in Science and Technology, Ser. Chemisꢀ
try and Technology of ighꢀMolecularꢀWeight Compounds],
VINITI, Moscow, 1978, 12, 47 (in Russian).
1
Rf 0.7 (fluorescent spot). H NMR, δ: 2.43 (s, 3 H, C6H4Me);
6.39 (s, 1 H, —CH=); 6.99 (d, 1 H, J = 8.0 Hz); 7.21—7.49
(m, 11 H); 7.73 (t, 1 H, J = 7.5 Hz); 7.98—8.05 (m, 3 H).
19F NMR, δ: –105.66 and –110.53 (both s, 1 F each).
2. I. I. Ponomarev, M. A. Baranova, Yu. A. Volkova, and A. S.
Peregudov, Polym. Sci. A, 2001, 43, 2081.
3. I. I. Ponomarev and D. Yu. Razorenov, in Polyimides and
Other HighꢀTemperature Polymers, Proc. 6th European Techꢀ
nical Symposium on Polyimides and High Performance Funcꢀ
tional Polymers (Montpellier, France, 13—16 May,
2002), Eds M. Abadie and B. Sillion, ISIM, Universite
Montpellier, 48.
4. D. Yu. Razorenov and I. I. Ponomarev, Tez. dokl. Malogo
polimernogo kongr. [Abstrs. of Papers, Small Polymer Conꢀ
gress] (November—December, 2005, Moscow), Moscow, 2005,
122 (in Russian).
5. O. A. Reutov, Teoreticheskie osnovy organicheskoi khimii
[Theoretical Fundamentals of Organic Chemistry], Izdꢀvo
MGU, Moscow, 1964, 538 (in Russian).
6. J. March, Advanced Organic Chemistry, J. Wiley and Sons,
New York, 1985.
2ꢀ[3,3ꢀBis(4ꢀbromophenyl)succinimido]ꢀNꢀ(4ꢀtolyl)benzꢀ
amide (6). Compound 4 (0.02 g, 0.0323 mmol) was dissolved in
DMSOꢀd6 (1 mL) on heating. Rf 0.6 (the spot shows no fluoreꢀ
1
scence). H NMR, δ: 2.30 (s, 3 H, Me); 3.58 and 3.78 (both d,
1 H each, CH2 of the succinimide fragment, J = 18.4 Hz);
7.13—7.90 (m, 16 H, H arom.); 10.45 (s, 1 H, NH).
2ꢀ[3,3ꢀBis(4ꢀfluorophenyl)succinimido]ꢀNꢀ(4ꢀtolyl)benzꢀ
amide (7). Compound 5 (0.1 g, 0.201 mmol) was refluxed in 85%
aqueous formic acid (5 mL) for two weeks. The solution was
cooled. The brown crystals (m.p. 210—223 °C) that precipitated
were separated from the mother liquor and dissolved on heating
in DMSOꢀd6 (2 mL). Rf 0.6 (the spot shows no fluorescence).
Found (%): C, 72.62; H, 4.45; F, 76.90; N, 5.68. C30H22F2N2O3.
Calculated (%): C, 72.57; H, 4.47; F, 76.50; N, 5.64. 1H NMR,
δ: 2.30 (s, 3 H, Me); 3.56 and 3.81 (both d, 1 H each, CH2 of the
succinimide fragment, J = 18.4 Hz); 6.99—7.81 (m, 16 H,
H arom.); 10.43 (s, 1 H, NH). 19F NMR, δ: –114.84 and –115.26
(both s, 1 F each).
Xꢀray diffraction study of compounds 2, 3, and 5. A single
crystal of compound 2 was grown by vacuum sublimation
(200 °C, the residual pressure was 0.01 Torr); a single crystal
of 3, by dissolution of compound 2 in refluxing formic acid
followed by evaporation of the solvent at ~20 °C for two weeks; a
single crystal of compound 5, by slow evaporation of a solution
of compound 5 in dioxane. The experimental data sets were
collected on Bruker SMART CCD Area Detector (at 120 К
for 2) and Syntex P21 (at 173 К for 3 and 193 K for 5)
diffractometers. The crystallographic data and the Xꢀray data
collection and refinement statistics are given in Table 1.
The structures were solved by direct methods. All nonꢀ
hydrogen atoms were located in difference electron density maps
and refined anisotropically against F 2hkl. The hydrogen atoms
were placed in geometrically calculated positions and refined
using a riding model with U(H) = nU(C) (n = 1.2 and 1.5 for the
sp2ꢀ and sp3ꢀhybridized carbon atoms, respectively; U(C) are
the equivalent thermal parameters of the C atoms to which the
corresponding H atoms are bound). All calculations were carꢀ
ried out using the SHELXTL PLUS 5 program package.9
7. L. A. Errede, J. Org. Chem., 1977, 42, 12.
8. L. A. Errede, J. Org. Chem., 1976, 41, 1743.
9. G. M. Sheldrick, SHELXTL (v. 5.10). Structure Determinaꢀ
tion Software Suite, Bruker AXS, Madison (Wisconsin,
USA), 1998.
10. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
M. A. Robb, J. R. Cheeseman, V. G. Zakrzewski, J. A.
Montgomery, Jr., R. E. Stratmann, J. C. Burant,
S. Dapprich, J. M. Millam, A. D. Daniels, K. N. Kudin,
M. C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi,
R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford,
J. Ochterski, G. A. Petersson, P. Y. Ayala, Q. Cui,
K. Morokuma, D. K. Malick, A. D. Rabuck,
K. Raghavachari, J. B. Foresman, J. Cioslowski, J. V. Ortiz,
B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz,
I. Komaromi, R. Gomperts, R. L. Martin, D. J. Fox,
T. Keith, M. A. AlꢀLaham, C. Y. Peng, A. Nanayakkara,
C. Gonzalez, M. Challacombe, P. M. W. Gill, B. G. Johnson,
W. Chen, M. W. Wong, J. L. Andres, M. HeadꢀGordon,
E. S. Replogle, and J. A. Pople, Gaussian 98 (Revision A.7),
Gaussian, Inc., Pittsburgh (PA), 1998.
Received July 20, 2006;
in revised form October 3, 2006