Synthesis and structure of 2-aryl-4H-acenaphth[5,6-bc]oxepin-4-ones

Article abstract of DOI:10.1134/S1070428007100090

Oxidation of 2-aryl-7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-ones with chloranil led to the formation of 2-aryl-4H-acenaphth[5,6-bc]oxepin-4-ones. Their spectral characteristics were analyzed, and a calculation of the molecular structure of model and real

Full text of DOI:10.1134/S1070428007100090

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 10, pp. 1466−1470. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © R.V. Tyurin, A.A. Milov, A.N. Bezuglov, A.N. Antonov, L.G. Minyaeva, V.V. Mezheritskii, 2007, published in Zhurnal Organicheskoi
Khimii, 2007, Vol. 43, No. 10, pp. 1474−1478.
Synthesis and Structure
of 2-Aryl-4H-acenaphth[5,6-bc]oxepin-4-ones
R. V. Tyurin, A. A. Milov, A. N. Bezuglov, A. N. Antonov, L. G. Minyaeva, and V. V. Mezheritskii
Institute of Physical and Organic Chemistry, Rostov State University, Rostov-on-Don, 344090 Russia
e-mail: mezher@ipoc.rsu.ru
Received September 28, 2006; in final form April 2, 2007
Abstract—Oxidation of 2-aryl-7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-ones with chloranil led to the formation
of 2-aryl-4H-acenaphth[5,6-bc]oxepin-4-ones. Their spectral characteristics were analyzed, and a calculation of
the molecular structure of model and real compounds was carried out.
DOI: 10.1134/S1070428007100090
of acenaphthene derivatives I into acenaphthylene II
occurs at dehydrogenation of the former with chloranil.
The idea of converting nonaromatic molecules into
aromatic by introducing one multiple bond is very
attractive since it permits direct contemplation of the
changes in the chemical and physical properties during
this transformation. Excellent objects of such
investigation are peri-fuzed heterocyclic derivatives of
acenaphthene and acenaphthylene.
IR spectra of compounds Ia, IIa and Ib, IIb do not
significantly differ in the characteristic region. The
carbonyl band of all compounds is located in the region
1630 cm–1, indicating, firstly, that it is influenced only
by the heterocyclic part of the molecule, and secondly,
the considerable “betainization” of the heteroring.
Studies we recently have begun [1] on purposeful
carrying out this idea concern in this report the
transformation of previously obtained [2] 2-aryl-
substituted 7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-
ones Ia and Ib into the corresponding 2-aryl-substituted
4H-acenaphth[5,6-bc]oxepin-4-ones IIa and IIb.
Compounds Ia, Ib, IIa, and IIb were studied by IR,
1H NMR, and mass spectroscopy, and also by quantum-
chemical calculations of real (R = Ar) and model (R =
H) compounds. The experimental and calculated spectral
characteristics of aromatic (IIa and IIb) and nonaromatic
molecules (Ia and Ib) were compared. The conversion
In the 1H NMR spectra of acenaphthene oxepinones
I the most upfield signal belongs to the singlet of the
proton from the heterocycle (6.34 and 6.30 ppm), and
the most downfield doublet signal originates from
aromatic proton H5 (8.44 and 8.38 ppm respectively).
The same protons in the spectra of acenaphthylene
derivatives II appear at 6.7, 6.65 and 6.74, 8.72 ppm
respectively. In other words, all spectrum in the region
of aromatic protons of acenaphthylene compounds II is
shifted downfield by 0.3–0.4 ppmcompared with
acenaphthene derivatives I which may be regarded as an
insignificant increase in the aromaticity of the former.
The double bond protons arising from dehydrogenation
of the bimethylene unit also gain an aromatic character
R
O
R
O
Cl
Cl
Cl
Cl
O
O
1
O
O
and appear as doublets in the H NMR spectra of
compounds II in the range 7.2–7.4 ppm
In the mass spectrum of 2-phenyl-7,8-dihydro-4H-
acenaphth[5,6-bc]oxepin-4-one (Ia) an ejection of
a hydrogen molecule was observed resulting in
transformation of molecular ion M1+ (Ia) into M2+ (IIa)
and concurrently occurred an elimination of phenyl-
acetylene to form an ion of acenaphtho[1,8-bc]furan-2-
_H2
Ia_Ic
IIa_IIc
R = Ph (a), 4-MeOC6H4 (b), H (c).
1466

SYNTHESIS AND STRUCTURE OF 2-ARYL-4H-ACENAPHTH[5,6-bc]OXEPIN-4-ONES
1467
.
+
electronic structure of the experimentally obtained
compounds and their simplified models. The study was
carried out in the framework of the density functional
theory by the method B3LYP/6-31G** applying software
GAUSSIAN 03 [3]. For model compounds Ic and IIc
were also performed additional calculations by the
method B3LYP/6-311+G** [2]. The results of the
theoretical treatment for various substituents demonstrat-
ed that the structural characteristics of systems I and II
in all cases considered were similar and notably differed
only in the region of the carbon-carbon bond which
changed the multiplicity (Fig. 1–3).
O
O
.
[Ia]+
M1+
_H2
_PhC CH
_102
Ф1 (196)
.
+
O
O
.
[IIa]+
M2+
It was also found that all nonhydrogen atoms of model
systems Ic and IIc form a mirror plane (Fig. 3).Asimilar
planar fragment is conserved in all substituted systems
at R = Ph, 4-MeOC6H4 (Fig. 1, 2), therewith the aromatic
substituents are outside of the conjugation plane of the
system (rotation angle ~30 deg) and are not involved in
the formation of the united π-system.
Ф2 (194)
one Φ1. The phenylacetylene elimination takes place also
with molecular ion M2 to give 5,6-dehydroacenaphtho-
+
[1,8-bc]furan-2-one Φ2.
Quantum-chemical calculations were performed in
order to establish the structural characteristics and
Notwithstanding the similarity of the structural
characteristics the distribution of the electron density in
Fig. 1. Geometrical characteristics of structures of 2-phenyl-7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-one (Ia) and 2-phenyl-4H-
acenaphth[5,6-bc]oxepin-4-one (IIa).
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TURIN et al.
1468
Fig. 2. Geometrical characteristics of structures of 2-(methoxyphenyl)-7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-one (Ib) and
2-(methoxyphenyl)-4H-acenaphth[5,6-bc]oxepin-4-one (IIb).
Fig. 3. Geometrical characteristics and charge distribution for the structures of 7,8-dihydro-4H-acenaphtho[5,6-bc]oxepin-4-one (Ic)
and 4H-acenaphthO[5,6-bc]oxepin-4-one (IIc).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 10 2007

SYNTHESIS AND STRUCTURE OF 2-ARYL-4H-ACENAPHTH[5,6-bc]OXEPIN-4-ONES
1469
Fig. 4. Charge distribution for the structures 7,8-dihydro-4H-acenaphtho[5,6-bc]oxepin-4-one (Ic) and 4H-acenaphtho[5,6-bc]oxepin-
4-one (IIc).
systems I and II is somewhat different (Fig. 4). For
instance, in system IIc the electron density is more
delocalized as shows, in particular, the lower value of
its dipole moment [3.516 D, for compound Ic 4.475 D].
This fact may serve an indirect confirmation of the higher
aromaticity of systems II than I.
2-(Methoxyphenyl)-7,8-dihydro-4H-acenaphth-
[5,6-bc]oxepin-4-one (Ib) [2]. IR spectrum, ν, cm–1:
1
1633, 1607, 1595. H NMR spectrum, δ, ppm: 3.40 m
(4H, CH2CH2), 3.90 s (3H, CH3O), 6.30 s (1H, H3),
6.98 d (2Harom, J 8.95 Hz), 7.22–7.36 m (3H, H6,9,10),
7.87 d (2Harom, J 7.95 Hz), 8.38 d (1H, H5, J 7.40 Hz).
2-Phenyl-4H-acenaphth[5,6-bc]oxepin-4-one (IIa).
A mixture of 0.1 g (0.34 mmol) of compound Ia and
0.165 g (0.68 mmol) of tetrachloro-1,4-benzoquinone
was boiled for 2 h in 3 ml of o-dichlorobenzene. The
solution was evaporated to dryness, the residue was
subjected to chromatography on aluminum oxide (eluent
chloroform). Yield 0.035 g (35%), mp 85–87°C. IR
EXPERIMENTAL
IR spectra of compoumds obtained were recorded on
a spectrophotometer Specord 71IR from mulls in mineral
oil. 1H and 13C NMR spectra were registered on a spec-
trometer Varian Unity-300 in CDCl3, internal reference
HMDS. Mass spectra were measured on a Kratos instru-
ment with a direct admission of a sample into the ion
source (ionizing energy 70 eV, control voltage 1.75 kV).
The spectra presented below of formerly prepared
compounds Ia and Ib were recorded once more on the
same instruments and under the same conditions as the
spectra of compounds IIa and IIb.
1
spectrum, ν, cm–1: 1625, 1600, 1580. H NMR spectrum,
δ, ppm: 6.70 s (1H, H3), 7.22 d (1H, H7, J 5.24 Hz),
7.37 d (1H, H8, J 5.24 Hz), 7.50 m (3H, HPh), 7.63 d
(1H, H5, J 7.58 Hz), 7.86 d (1H, H6, J 7.58 Hz), 7.96–
8.20 m (3H, H10 + HPh), 8.74 d (1H, H9, J 7.36 Hz).
Mass spectrum, m/z (Irel, %): 296 [M2]+ (20), 194 (Φ2)
(100), 138 (80). Found, %: C 85.32; H 3.85. C21H12O2.
Calculated, %: C 85.14; H 4.05. M 296.324.
2-Phenyl-7,8-dihydro-4H-acenaphth[5,6-
bc]oxepin-4-one (Ia) [2]. IR spectrum, ν, cm–1: 1630,
1607, 1593. 1H NMR spectrum, δ, ppm: 3.45 m (4H,
CH2CH2), 6.34 s (1H, H3), 7.28 d (1H, H10, J 7.61 Hz),
7.33 d (1H, H6, J 7.41 Hz), 7.37 d (1H, H9, J 7.61 Hz),
7.46–7.52 m (3H, HPh), 7.87–7.94 m (2H, HPh), 8.40 d
(1H, H5, J 7.44 Hz). Mass spectrum, m/z (Irel, %): 298
[M1]+ (28), 296 [M2]+ (22), 196 (Τ1) (70), 194 (Φ2) (100),
138 (90).
2-(Methoxyphenyl)-4H-acenaphth[5,6-bc]oxepin-
4-one (IIb ) was similarly prepared. Yield 40%, mp 144–
1
147°C. IR spectrum, ν, cm–1: 1625, 1600, 1580. H NMR
spectrum, δ, ppm: 3.80 s (3H, CH3O), 6.53 s (1H, H3),
7.03 d (2Harom, J 8.94 Hz), 7.21 d (1H, H7, J 5.24 Hz),
7.35 d (1H, H8), 7.61 d (1H, H5, J 7.58 Hz), 7.85 d (1H,
H6, J 7.54 Hz), 7.96 d (2Harom, J 8.94 Hz), 7.98 d (1H,
H10, J 7.36 Hz), 8.72 d (1H, H9, J 7.36 Hz). Found, %:
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 10 2007

TURIN et al.
1470
C 81.37; H 4.00. C22H14O3. Calculated, %: C 80.98;
H 4.29.
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tao, O., Nakai, H., Klene, M., Li, X., Knox, J.E., Hrat-
chian, H.P., Cross, J.B., Adamo, C., Jaramillo, J., Gom-
perts, R., Stratmann, R.E., Yazyev, O., Austin, A.J., Cam-
mi, R., Pomelli, C., Ochterski, J.W., Ayala, P.Y., Moroku-
ma, K., Voth, G.A., Salvador, P., Dannenberg, J.J.,
Zakrzewski, V.G., Dapprich, S., Daniels,A.D., Strain, M.C.,
Farkas, O., Malick, D.K., Rabuck, A.D., Raghavachari, K.,
Foresman, J.B., Ortiz, J.V., Cui, Q., Baboul, A.G., Clif-
ford, S., Cioslow-ski, J., Stefanov, B.B., Liu, G., Liashen-
ko, A., Piskorz, P., Koma-romi, I., Martin, R.L., Fox, D.J.,
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03, Revision, B.03, Gaussian Inc., Pittsburgh, PA, 2003.
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