3-(3-Oxo-1,3-dihydro-isobenzofuran-1-yl-idene)pentane-2,4-dione

Article abstract of DOI:10.1107/S0108270107017866

In the title compound, C13H10O4, prepared by the condensation reaction between phthalic anhydride and pentane-2,4-dione, one of the acetyl groups in the pentane-2,4-dione fragment is almost coplanar with the isobenzofuran ring system, while the other group is twisted out of this plane by almost 80°. The corresponding C - C and C - O distances in the two acetyl units are consistent with dipolar delocalization into the coplanar unit only. There is no supra-molecular aggregation of the mol-ecules, but a number of rather short inter-molecular contacts of C - H...O, O...O and O...C types occur. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107017866

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
dione fragment are thus consistent with the dipolar form (Ia)
(see scheme) as a signi®cant contributor to the overall mol-
ecular electronic structure, but the close similarity of the CÐO
distances in the furan ring effectively rules out any contribu-
tion from dipolar form (Ib).
ISSN 0108-2701
3-(3-Oxo-1,3-dihydroisobenzofuran-
1-ylidene)pentane-2,4-dione
Jaime Portilla,a Jairo Quiroga,a Justo Cobo,b John N. Lowc
and Christopher Glidewelld*
a
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Grupo de Investigacion de Compuestos, Heterociclõcos, Departamento de Quõmica,
b
Â
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Universidad de Valle, AA 25360, Colombia, Departamento de Quõmica Inorganica
y Organica, Universidad de Jaen, 23071 Jaen, Spain, cDepartment of Chemistry,
University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and
dSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
Â
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Received 9 April 2007
Accepted 10 April 2007
Online 11 May 2007
In the title compound, C13H10O4, prepared by the condensa-
tion reaction between phthalic anhydride and pentane-2,4-
dione, one of the acetyl groups in the pentane-2,4-dione
fragment is almost coplanar with the isobenzofuran ring
system, while the other group is twisted out of this plane by
almost 80ꢀ. The corresponding CÐC and CÐO distances in
the two acetyl units are consistent with dipolar delocalization
into the coplanar unit only. There is no supramolecular
aggregation of the molecules, but a number of rather short
intermolecular contacts of CÐHÁ Á ÁO, OÁ Á ÁO and OÁ Á ÁC types
occur.
There are two direction-speci®c intermolecular interactions
of possible signi®cance in the structure of (I). The ®rst is a CÐ
HÁ Á ÁO interaction (Table 2), where the HÁ Á ÁO distances is
probably too long and the CÐHÁ Á ÁO angle is probably too
small for this contact to be described as a signi®cant hydrogen
bond. Since both the C and the O atoms involved are located
in the isobenzofuran ring, it is not possible to ®nd in this
interaction any explanation for the differing conformations of
the two acetyl units. The second interaction involves rather
short contacts between acetyl atom O2 in the molecule at (x, y,
z) and the sequence of atoms C31, O32 and C33 in the mol-
ecule at ( x, 1 y, 1 z); the interatomic distances to C31,
O32 and C33 are, respectively, 2.994 (2), 2.831 (2) and
Comment
As part of a programme for the synthesis of new fused
heterocyclic systems of potential biological interest, we have
evaluated the use of 3-(3-oxo-1,3-dihydroisobenzofuran-1-yl-
idene)pentane-2,4-dione, (I), as a new ꢀ,ꢁ-unsaturated ketone
derivative. We report here the structure of (I), which was
prepared by condensation of phthalic anhydride and pentane-
2,4-dione.
Ê
3.005 (2) A, associated with CÐHÁ Á ÁX angles of 126.5 (2),
The bond lengths within the carbocyclic ring span the very
Ê
narrow range 1.387 (2)±1.394 (2) A, indicative of unperturbed
aromatic delocalization; in the heterocyclic ring, the C31Ð
C37A and C33ÐC33A distances are very similar (Table 1), as
are the C31ÐO32 and C33ÐO32 distances. However, in the
pentane-2,4-dione fragment, the two C O distances are
signi®cantly different, as are the C2ÐC3 and C3ÐC4
distances. These differences in bond lengths are associated
with the conformations adopted by the two acetyl groups.
Atoms C2, C3, C4, O4 and C5 are almost coplanar with the
isobenzofuran unit, as shown by the key torsion angles
(Table 1). However, the C1/C2/O2 acetyl group is twisted out
of this plane by almost 80ꢀ (Table 1 and Fig. 1); the dihedral
angles between the C1±C3/O2 and C2/C3/C4/C31/O32 mean
planes is 79.7 (2)ꢀ. The bond distances in the pentane-2,4-
Figure 1
The molecular structure of (I), showing the atom-labelling scheme.
Displacement ellipsoids are drawn at the 30% probability level.
o332 # 2007 International Union of Crystallography
DOI: 10.1107/S0108270107017866
Acta Cryst. (2007). C63, o332±o333

organic compounds
153.6 (2) and 144.0 (2)ꢀ for X = C31, O32 and C33, respec-
tively. The expected polarization of the O and C atoms
involved suggests that the O2Á Á ÁO32ii interaction [symmetry
code: (ii) x, y + 1, z + 1] is repulsive, while the O2Á Á ÁC31ii
and O2Á Á ÁC33ii interactions are both attractive. As with the
intermolecular CÐHÁ Á ÁO contact, it is not easy to see in these
OÁ Á ÁO and OÁ Á ÁC contacts any simple explanation for the
molecular conformation of (I).
In contrast to the molecular conformation adopted by (I), in
3-(triphenylphosphoranylidene)pentane-2,4-dione, (II), the
entire pentane-2,4-dione unit is close to planarity in the syn±
anti conformation, with only modest differences between the
corresponding bond distances in the two acetyl units (Casta-
nÄeda et al., 2005). However, in the closely-related compound
diethyl 2-(triphenylphosphoranylidene)malonate, (III), both
ester units are twisted out of the plane of the central PC3 unit
(CastanÄeda et al., 2005).
Re®nement
R[F2 > 2ꢃ(F2)] = 0.048
wR(F2) = 0.139
S = 1.08
156 parameters
H-atom parameters constrained
3
Ê
Áꢄmax = 0.27 e A
3
Ê
0.24 e A
2426 re¯ections
Áꢄmin
=
Table 2
ꢀ
Ê
Parameters for the short intermolecular CÐHÁ Á ÁO contact (A, ).
DÐHÁ Á ÁA
C35ÐH35Á Á ÁO33i
Symmetry code: (i) x; y ‡ 12; z
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
0.95
2.57
3.256 (2)
130
1
2
.
The space group P21/c was uniquely assigned from the systematic
absences. All H atoms were located in difference maps and then
treated as riding atoms in geometrically idealized positions, with CÐ
Ê
H distances of 0.95 (aromatic) or 0.98 A (methyl), and with Uiso(H) =
kUeq(C), where k = 1.2 for the aromatic ring and k = 1.5 for the
methyl groups.
Data collection: COLLECT (Hooft, 1999); cell re®nement:
DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD
(Duisenberg et al., 2003); program(s) used to solve structure: SIR2004
(Burla et al., 2005) and WinGX (Farrugia, 1999); program(s) used to
re®ne structure: OSCAIL (McArdle, 2003) and SHELXL97 (Shel-
drick, 1997); molecular graphics: PLATON (Spek, 2003); software
used to prepare material for publication: SHELXL97 and
PRPKAPPA (Ferguson, 1999).
Experimental
To a solution of phthalic anhydride (20 mmol) and pentane-2,4-dione
(20 mmol) in acetic anhydride (11.3 ml) at 298 K, triethylamine
(40 mmol) was added dropwise and the mixture stirred for 30 min.
The reaction was quenched by the addition of aqueous hydrochloric
acid (45 ml of 1 mol dm 3 solution). The resulting solid was collected
by ®ltration, and washed with diethyl ether (two aliquots of 25 ml)
and then with hexane (two aliquots of 25 ml) to give (I) as colourless
crystals, which were suitable for single-crystal X-ray diffraction (yield
90%; m.p. 406±408 K). MS (70 eV) m/z (%): 230 (5, M+), 187 (39),
172 (100), 104 (39), 89 (74), 76 (38), 43 (66), 42 (96), 15 (44).
Â
The authors thank `Servicios Tecnicos de Investigacion of
Universidad de Jaen' and the staff for data collection. JC
Â
Â
Â
Â
thanks the Consejerõa de Innovacion, Ciencia y Empresa
Â
Â
(Junta de Andalucõa, Spain) and the Universidad de Jaen for
®nancial support. JP and JQ thank COLCIENCIAS and
UNIVALLE (Universidad del Valle, Colombia) for ®nancial
support.
Crystal data
3
Ê
C13H10O4
Mr = 230.21
V = 1056.90 (12) A
Z = 4
Monoclinic, P21=c
Mo Kꢀ radiation
ꢂ = 0.11 mm
T = 120 (2) K
0.52 Â 0.31 Â 0.08 mm
1
Ê
a = 8.2779 (3) A
Ê
b = 8.4719 (6) A
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SK3122). Services for accessing these data are
described at the back of the journal.
Ê
c = 15.1413 (12) A
ꢁ = 95.534 (6)ꢀ
Data collection
Bruker±Nonius KappaCCD
diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.964, Tmax = 0.991
25118 measured re¯ections
2426 independent re¯ections
1813 re¯ections with I > 2ꢃ(I)
Rint = 0.043
References
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Table 1
Selected geometric parameters (A, ).
Duisenberg, A. J. M., Hooft, R. W. W., Schreurs, A. M. M. & Kroon, J. (2000).
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ꢀ
Ê
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C2ÐO2
C4ÐO4
C2ÐC3
C3ÐC4
C3ÐC31
1.211 (2)
1.225 (2)
1.518 (2)
1.489 (2)
1.348 (3)
C31ÐC37A
C33ÐC33A
O32ÐC31
O32ÐC33
C33ÐO33
1.470 (2)
1.464 (2)
1.389 (2)
1.387 (2)
1.204 (2)
C2ÐC3ÐC31ÐO32
O2ÐC2ÐC3ÐC31
C1ÐC2ÐC3ÐC31
175.40 (14)
77.9 (2)
101.57 (19)
C4ÐC3ÐC31ÐO32
O4ÐC4ÐC3ÐC31
C5ÐC4ÐC3ÐC31
6.2 (3)
175.99 (17)
6.1 (3)
È
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Germany.
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ꢁ
Acta Cryst. (2007). C63, o332±o333
Portilla et al. C13H10O4 o333