organic compounds
8,8-Diethyl-1,4,5,8-tetrahydronaphthalene-1,4,5-trione
aUniversidad Andres Bello, Departamento de Ciencias Químicas, Av Republica 275, Santiago, Chile, bDepartamento de Química Orgánica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile, and cCIMAT, Universidad de Chile, Av. Blanco Encalada 2008, Santiago, Chile
*Correspondence e-mail: raraya@ciq.uchile.cl
The title molecule, C14H14O3, contains two fused six-membered carbon rings with keto groups at positions 1, 4 and 5 and a gem-diethyl group at position 8. The molecule is close to planar (maximum deviation = 0.044 Å), with one ethyl group at each side of the molecular plane, with exception of the keto group at position 1 which is slightly deviated from the plane and disordered over two positions one on each side of it (occupancies 0.80/0.20). The packing of the molecule shows weak bonded chains along a through C—H⋯O contacts and two intramolecular C—H⋯O interactions are also present.
Related literature
For the biologically active dimethyl analog, see: Araya-Maturana et al. (2002); for its use as a substrate for Diels-Alder cycloadditions with 2,4-hexadienol, see: Araya-Maturana et al. (1999) and for the synthesis of biologically active compounds, see: Araya-Maturana et al. (2006); Mendoza et al. (2005); Rodríguez et al. (2007). For details of the synthesis of the 4,4-dimethyl analog, see: Castro et al. (1983); Vega et al. (2008).
Experimental
Crystal data
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Refinement
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Data collection: SMART-NT (Bruker, 2001); cell SAINT-NT (Bruker, 1999); data reduction: SAINT-NT; program(s) used to solve structure: SHELXTL-NT (Sheldrick, 2008); program(s) used to refine structure: SHELXTL-NT; molecular graphics: SHELXTL-NT; software used to prepare material for publication: SHELXTL-NT.
Supporting information
10.1107/S1600536809001755/gw2058sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809001755/gw2058Isup2.hkl
Synthesis of I. The title compound was prepared by oxydation of the corresponding hydroquinone B; obtained by rearrangement of the furane parent compound A (Vega et al., 2008); with MnO2 as shown in Fig. 3. This procedure have been previously described for the 4,4-dimethyl analog (Castro et al., 1983). X-ray quality crystals were obtained through recrystallization from benzene.
Spectroscopic Details. 1H and 13C NMR spectra were acquired using a Bruker AVANCE DRX 300 spectrometer operating at 300.13 MHz (1H) or 75.47 MHz (13C). All measurements were carried out at a probe temperature of 300 K. 1HNMR (CDCl3): 0.62(6H, t, J = 7.5 Hz, 2X CH3); 1.70(2H, dq, J1 = 7.5 Hz, J2 = 13.8 Hz, 2X CHH,); 2.52(2H, dq, J1 = 7.5 Hz, J2 = 13.8 Hz, 2X CHH); 6.53(1H, d, J = 10.2 Hz); 6.58(1H, d, J = 10.2 HZ). 13CNMR(CDCl3): 8.42, 31.41, 48.13, 130.77, 132.79, 135.32, 135.57, 152.59, 154.51, 182.46, 183.13, 186.76.
The hydrogen atoms positions were calculated after each cycle of
with SHELXL (Bruker,1999) using a riding model for each structure, with C—H distances in the range 0.96 to 1.00 Å. Uiso(H) values were set equal to 1.5Ueq of the parent carbon atom for methyl groups and 1.2Ueq for the others. During the final stages of some disorder on the position of the oxo oxygen atom O3 was evident. It was modelled using two positions labelled i and ii with partial occupation of 0.80 and 0.20 respectively.Data collection: SMART-NT (Bruker, 2001); cell
SAINT-NT (Bruker, 1999); data reduction: SAINT-NT (Bruker, 1999); program(s) used to solve structure: SHELXTL-NT (Sheldrick, 2008); program(s) used to refine structure: SHELXTL-NT (Sheldrick, 2008); molecular graphics: SHELXTL-NT (Sheldrick, 2008); software used to prepare material for publication: SHELXTL-NT (Sheldrick, 2008).C14H14O3 | F(000) = 488 |
Mr = 230.25 | Dx = 1.254 Mg m−3 |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 4760 reflections |
a = 12.7454 (8) Å | θ = 24.9–50.1° |
b = 10.8015 (7) Å | µ = 0.09 mm−1 |
c = 8.8598 (5) Å | T = 150 K |
V = 1219.72 (13) Å3 | Block, red |
Z = 4 | 0.49 × 0.48 × 0.46 mm |
Siemens SMART CCD area-detector diffractometer | 2159 independent reflections |
Radiation source: fine-focus sealed tube | 2119 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.012 |
ϕ and ω scans | θmax = 25.1°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −15→15 |
Tmin = 0.958, Tmax = 0.961 | k = −12→12 |
6581 measured reflections | l = −10→10 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0642P)2 + 0.3077P] where P = (Fo2 + 2Fc2)/3 |
2159 reflections | (Δ/σ)max < 0.001 |
166 parameters | Δρmax = 0.26 e Å−3 |
15 restraints | Δρmin = −0.15 e Å−3 |
C14H14O3 | V = 1219.72 (13) Å3 |
Mr = 230.25 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 12.7454 (8) Å | µ = 0.09 mm−1 |
b = 10.8015 (7) Å | T = 150 K |
c = 8.8598 (5) Å | 0.49 × 0.48 × 0.46 mm |
Siemens SMART CCD area-detector diffractometer | 2159 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 2119 reflections with I > 2σ(I) |
Tmin = 0.958, Tmax = 0.961 | Rint = 0.012 |
6581 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 15 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.26 e Å−3 |
2159 reflections | Δρmin = −0.15 e Å−3 |
166 parameters |
Experimental. 0.3 ° between frames and 10 secs exposure (per frame) |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.05513 (10) | 0.73723 (13) | 0.2345 (2) | 0.0588 (5) | |
C1 | 0.12734 (12) | 0.80829 (16) | 0.2581 (2) | 0.0312 (4) | |
C2 | 0.23531 (13) | 0.76647 (15) | 0.24985 (19) | 0.0298 (4) | |
H2 | 0.2495 | 0.6828 | 0.2240 | 0.036* | |
C3 | 0.31458 (12) | 0.84252 (16) | 0.2775 (2) | 0.0298 (4) | |
H3 | 0.3834 | 0.8091 | 0.2713 | 0.036* | |
C4 | 0.30503 (12) | 0.97639 (16) | 0.3177 (2) | 0.0264 (4) | |
C9 | 0.36538 (13) | 1.04995 (17) | 0.1926 (2) | 0.0343 (4) | |
H9A | 0.3713 | 1.1375 | 0.2244 | 0.041* | |
H9B | 0.4373 | 1.0161 | 0.1842 | 0.041* | |
C10 | 0.31363 (17) | 1.04521 (19) | 0.0381 (2) | 0.0428 (5) | |
H10A | 0.3037 | 0.9587 | 0.0080 | 0.064* | |
H10B | 0.3585 | 1.0871 | −0.0358 | 0.064* | |
H10C | 0.2454 | 1.0868 | 0.0426 | 0.064* | |
C11 | 0.36382 (13) | 0.99525 (17) | 0.4703 (2) | 0.0341 (4) | |
H11A | 0.4375 | 0.9680 | 0.4579 | 0.041* | |
H11B | 0.3648 | 1.0847 | 0.4944 | 0.041* | |
C12 | 0.31612 (17) | 0.92627 (19) | 0.6018 (2) | 0.0446 (5) | |
H12A | 0.2431 | 0.9523 | 0.6151 | 0.067* | |
H12B | 0.3559 | 0.9446 | 0.6938 | 0.067* | |
H12C | 0.3185 | 0.8371 | 0.5818 | 0.067* | |
C4A | 0.19164 (12) | 1.01751 (15) | 0.32711 (18) | 0.0257 (3) | |
C5 | 0.17023 (12) | 1.15035 (15) | 0.3703 (2) | 0.0302 (4) | |
O2 | 0.24055 (10) | 1.22495 (10) | 0.38734 (17) | 0.0391 (3) | |
C6 | 0.05978 (14) | 1.18870 (18) | 0.3909 (3) | 0.0440 (5) | |
H6 | 0.0453 | 1.2693 | 0.4283 | 0.053* | |
C7 | −0.01884 (14) | 1.11471 (18) | 0.3592 (3) | 0.0444 (5) | |
H7 | −0.0887 | 1.1421 | 0.3759 | 0.053* | |
C8 | −0.00040 (15) | 0.9904 (2) | 0.2982 (3) | 0.0515 (6) | |
O3i | −0.07253 (14) | 0.93529 (18) | 0.2268 (3) | 0.0604 (6) | 0.80 |
O3ii | −0.0669 (5) | 0.9189 (6) | 0.3592 (11) | 0.063 (2) | 0.20 |
C8A | 0.11022 (12) | 0.94198 (15) | 0.2963 (2) | 0.0304 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0288 (7) | 0.0394 (7) | 0.1082 (15) | −0.0062 (6) | −0.0007 (8) | −0.0163 (8) |
C1 | 0.0240 (8) | 0.0302 (8) | 0.0396 (10) | −0.0027 (7) | 0.0001 (7) | 0.0002 (7) |
C2 | 0.0308 (8) | 0.0257 (8) | 0.0329 (10) | 0.0031 (6) | 0.0016 (7) | −0.0017 (7) |
C3 | 0.0214 (7) | 0.0342 (8) | 0.0338 (9) | 0.0049 (6) | 0.0014 (7) | 0.0024 (7) |
C4 | 0.0215 (7) | 0.0294 (8) | 0.0284 (8) | −0.0011 (6) | 0.0010 (6) | 0.0005 (7) |
C9 | 0.0282 (8) | 0.0360 (9) | 0.0388 (10) | −0.0042 (7) | 0.0057 (7) | 0.0027 (7) |
C10 | 0.0515 (12) | 0.0436 (11) | 0.0332 (10) | −0.0007 (9) | 0.0069 (9) | 0.0041 (8) |
C11 | 0.0287 (8) | 0.0394 (9) | 0.0341 (9) | 0.0005 (7) | −0.0061 (7) | −0.0012 (8) |
C12 | 0.0541 (12) | 0.0486 (11) | 0.0311 (10) | 0.0022 (9) | −0.0036 (9) | 0.0016 (9) |
C4A | 0.0235 (7) | 0.0284 (8) | 0.0251 (8) | 0.0014 (6) | −0.0006 (6) | 0.0021 (6) |
C5 | 0.0325 (8) | 0.0293 (8) | 0.0288 (8) | 0.0035 (7) | −0.0009 (7) | 0.0004 (7) |
O2 | 0.0424 (7) | 0.0303 (6) | 0.0446 (8) | −0.0047 (5) | −0.0031 (6) | −0.0033 (6) |
C6 | 0.0392 (10) | 0.0339 (9) | 0.0589 (13) | 0.0110 (8) | 0.0016 (10) | −0.0084 (10) |
C7 | 0.0287 (9) | 0.0454 (11) | 0.0591 (12) | 0.0122 (8) | 0.0028 (9) | −0.0022 (9) |
C8 | 0.0220 (8) | 0.0379 (9) | 0.0946 (17) | 0.0012 (7) | 0.0008 (10) | −0.0040 (11) |
O3i | 0.0286 (9) | 0.0545 (11) | 0.0980 (17) | 0.0031 (8) | −0.0155 (11) | −0.0103 (12) |
O3ii | 0.016 (3) | 0.050 (4) | 0.122 (7) | −0.006 (3) | 0.012 (4) | −0.032 (5) |
C8A | 0.0219 (8) | 0.0308 (8) | 0.0385 (9) | 0.0031 (6) | 0.0008 (7) | 0.0020 (7) |
O1—C1 | 1.217 (2) | C11—H11A | 0.9900 |
C1—C2 | 1.450 (2) | C11—H11B | 0.9900 |
C1—C8A | 1.499 (2) | C12—H12A | 0.9800 |
C2—C3 | 1.325 (2) | C12—H12B | 0.9800 |
C2—H2 | 0.9500 | C12—H12C | 0.9800 |
C3—C4 | 1.494 (2) | C4A—C8A | 1.348 (2) |
C3—H3 | 0.9500 | C4A—C5 | 1.510 (2) |
C4—C4A | 1.514 (2) | C5—O2 | 1.215 (2) |
C4—C11 | 1.559 (2) | C5—C6 | 1.479 (2) |
C4—C9 | 1.566 (2) | C6—C7 | 1.312 (3) |
C9—C10 | 1.520 (3) | C6—H6 | 0.9500 |
C9—H9A | 0.9900 | C7—C8 | 1.467 (3) |
C9—H9B | 0.9900 | C7—H7 | 0.9500 |
C10—H10A | 0.9800 | C8—O3i | 1.264 (3) |
C10—H10B | 0.9800 | C8—O3ii | 1.267 (3) |
C10—H10C | 0.9800 | C8—C8A | 1.504 (2) |
C11—C12 | 1.511 (3) | ||
O1—C1—C2 | 120.84 (16) | C12—C11—H11B | 108.7 |
O1—C1—C8A | 122.44 (15) | C4—C11—H11B | 108.7 |
C2—C1—C8A | 116.72 (14) | H11A—C11—H11B | 107.6 |
C3—C2—C1 | 121.40 (15) | C11—C12—H12A | 109.5 |
C3—C2—H2 | 119.3 | C11—C12—H12B | 109.5 |
C1—C2—H2 | 119.3 | H12A—C12—H12B | 109.5 |
C2—C3—C4 | 125.59 (15) | C11—C12—H12C | 109.5 |
C2—C3—H3 | 117.2 | H12A—C12—H12C | 109.5 |
C4—C3—H3 | 117.2 | H12B—C12—H12C | 109.5 |
C3—C4—C4A | 112.01 (13) | C8A—C4A—C5 | 119.17 (14) |
C3—C4—C11 | 107.09 (15) | C8A—C4A—C4 | 123.10 (14) |
C4A—C4—C11 | 111.88 (13) | C5—C4A—C4 | 117.72 (13) |
C3—C4—C9 | 106.41 (14) | O2—C5—C6 | 120.09 (15) |
C4A—C4—C9 | 111.04 (13) | O2—C5—C4A | 121.91 (14) |
C11—C4—C9 | 108.14 (13) | C6—C5—C4A | 118.00 (14) |
C10—C9—C4 | 114.02 (15) | C7—C6—C5 | 122.00 (16) |
C10—C9—H9A | 108.7 | C7—C6—H6 | 119.0 |
C4—C9—H9A | 108.7 | C5—C6—H6 | 119.0 |
C10—C9—H9B | 108.7 | C6—C7—C8 | 120.96 (16) |
C4—C9—H9B | 108.7 | C6—C7—H7 | 119.5 |
H9A—C9—H9B | 107.6 | C8—C7—H7 | 119.5 |
C9—C10—H10A | 109.5 | O3i—C8—O3ii | 56.0 (4) |
C9—C10—H10B | 109.5 | O3i—C8—C7 | 119.90 (18) |
H10A—C10—H10B | 109.5 | O3ii—C8—C7 | 107.1 (4) |
C9—C10—H10C | 109.5 | O3i—C8—C8A | 120.9 (2) |
H10A—C10—H10C | 109.5 | O3ii—C8—C8A | 114.8 (4) |
H10B—C10—H10C | 109.5 | C7—C8—C8A | 118.20 (17) |
C12—C11—C4 | 114.25 (14) | C4A—C8A—C1 | 121.11 (14) |
C12—C11—H11A | 108.7 | C4A—C8A—C8 | 120.61 (15) |
C4—C11—H11A | 108.7 | C1—C8A—C8 | 118.27 (15) |
O1—C1—C2—C3 | −178.98 (19) | C4—C4A—C5—C6 | −175.48 (16) |
C8A—C1—C2—C3 | 1.2 (2) | O2—C5—C6—C7 | 173.1 (2) |
C1—C2—C3—C4 | −0.7 (3) | C4A—C5—C6—C7 | −6.5 (3) |
C2—C3—C4—C4A | 1.2 (3) | C5—C6—C7—C8 | −1.3 (3) |
C2—C3—C4—C11 | 124.22 (18) | C6—C7—C8—O3i | −158.7 (3) |
C2—C3—C4—C9 | −120.31 (19) | C6—C7—C8—O3ii | 141.2 (5) |
C3—C4—C9—C10 | 68.10 (19) | C6—C7—C8—C8A | 9.7 (3) |
C4A—C4—C9—C10 | −54.0 (2) | C5—C4A—C8A—C1 | −177.87 (16) |
C11—C4—C9—C10 | −177.13 (15) | C4—C4A—C8A—C1 | 3.4 (3) |
C3—C4—C11—C12 | −64.03 (18) | C5—C4A—C8A—C8 | 2.6 (3) |
C4A—C4—C11—C12 | 59.1 (2) | C4—C4A—C8A—C8 | −176.14 (17) |
C9—C4—C11—C12 | −178.34 (15) | O1—C1—C8A—C4A | 177.64 (19) |
C3—C4—C4A—C8A | −2.6 (2) | C2—C1—C8A—C4A | −2.6 (2) |
C11—C4—C4A—C8A | −122.82 (18) | O1—C1—C8A—C8 | −2.9 (3) |
C9—C4—C4A—C8A | 116.25 (18) | C2—C1—C8A—C8 | 176.95 (18) |
C3—C4—C4A—C5 | 178.65 (16) | O3i—C8—C8A—C4A | 157.9 (2) |
C11—C4—C4A—C5 | 58.39 (19) | O3ii—C8—C8A—C4A | −138.3 (5) |
C9—C4—C4A—C5 | −62.53 (18) | C7—C8—C8A—C4A | −10.3 (3) |
C8A—C4A—C5—O2 | −173.95 (17) | O3i—C8—C8A—C1 | −21.6 (3) |
C4—C4A—C5—O2 | 4.9 (2) | O3ii—C8—C8A—C1 | 42.2 (5) |
C8A—C4A—C5—C6 | 5.7 (3) | C7—C8—C8A—C1 | 170.2 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.95 | 2.27 | 3.207 (2) | 169 |
C9—H9A···O2 | 0.99 | 2.40 | 3.014 (2) | 120 |
C11—H11B···O2 | 0.99 | 2.39 | 3.027 (2) | 122 |
Symmetry code: (i) x+1/2, −y+3/2, z. |
Experimental details
Crystal data | |
Chemical formula | C14H14O3 |
Mr | 230.25 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 150 |
a, b, c (Å) | 12.7454 (8), 10.8015 (7), 8.8598 (5) |
V (Å3) | 1219.72 (13) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.49 × 0.48 × 0.46 |
Data collection | |
Diffractometer | Siemens SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.958, 0.961 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6581, 2159, 2119 |
Rint | 0.012 |
(sin θ/λ)max (Å−1) | 0.596 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.099, 1.00 |
No. of reflections | 2159 |
No. of parameters | 166 |
No. of restraints | 15 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.26, −0.15 |
Computer programs: SMART-NT (Bruker, 2001), SAINT-NT (Bruker, 1999), SHELXTL-NT (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3···O1i | 0.95 | 2.27 | 3.207 (2) | 169 |
C9—H9A···O2 | 0.99 | 2.40 | 3.014 (2) | 120 |
C11—H11B···O2 | 0.99 | 2.39 | 3.027 (2) | 122 |
Symmetry code: (i) x+1/2, −y+3/2, z. |
Acknowledgements
The authors gratefully acknowledge generous financial support from FONDECYT 1071077.
References
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Vega, A., Ramírez-Rodríguez, O., Martínez-Cifuentes, M., Ibañez, A. & Araya-Maturana, R. (2008). Acta Cryst. E64, o2329. Web of Science CSD CrossRef IUCr Journals Google Scholar
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The title quinone (I) is closely related to its biologically active dimethyl analog 8,8-dimethylnaphtalene-1,4,5(8H)-trione (Araya-Maturana et al. 2002), which has been used as substrate for highly regioselective Diels-Alder cycloadditions with 2,4-hexadienol (Araya-Maturana et al. 1999) and for the synthesis of biologically active compounds (Rodríguez et al. 2007; Araya-Maturana et al. 2006; Mendoza et al. 2005). The 1H-NMR spectrum of the title compound exhibits equivalence of both ethyl groups, evidencing the existence of a symmetry plane in the molecule. It displays a single triplet for both methyl groups but two sextuplets for the methylene protons of the ethyl substituents; with couplings constant of 7.3 Hz and 15.4 Hz for the vecinal and geminal ones respectively. This evidences a rotational restriction for the chains. The non-equivalence of the signals of methylene protons in a non-chiral molecule could be envisoned supposing a rotational constrain exerted by the non bonding electrons of the near carbonyl group, avoiding the rotation of the bond between methylene groups and the quaternary carbon bearing the geminal ethyl groups. This hypotesis based on NMR solution data was tested for the present crystal structure.
The molecule I contains two six membered carbon rings fused, a p-quinone and a dienone core (Scheme 1). The dienone ring is highly planar mainly because of the insaturations in the carbon skeleton, while the quinonic framework displays a slightly distorted boat conformation, with one keto oxygen atom slightly out of the plane of the rest of the ring (see torsion angles). As described in the experimental section, the keto oxygen atom O3 is disordered over two positions of ocuppancy 0.80 and 0.20. placed at opposite sides of the molecular plane. This could be related to the equivalence of the methylene 1H-NMR signals in solution in the following way: the two conformations are probably very close (if not equal) in energy and rapid interconversion occurs in the NMR timescale. The situation is consistent with the observation of two positions for the keto oxygen atom in the crystal strcuture.
The crystal packing of the molecule shows weak bonded zigzag chains along the a cell axis, through C—H···O interactions, as depicted in Figure 2.