Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802015283/ci6143sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536802015283/ci6143Isup2.hkl |
CCDC reference: 198329
The title compound was obtained by the reaction of diethyl ketone with o-chlorobenzaldehyde in 80% ethanol. Diffraction quality crystals were obtained by recrystallization from ethanol. 1H NMR (CDCl3, p.p.m.): δ = 0.92 (d, 6H, J = 6.3), 2.87 (m, 2H), 3.93 (t, 2H, J = 12.0), 3.38 (dt, 1H, 3J = 4.8, 2J = 12.2), 7.1–7.8 (m, 8H), 9.21 (d, 1H, J = 4.5).
Since the Friedel pairs were not measured during the data collection, we were unable to determine the absolute structure. All the H atoms were fixed geometrically and allowed to ride on the parent C atoms, with aromatic C—H = 0.93 Å, tertiary C—H = 0.97 Å and methyl C—H = 0.96 Å. The displacement parameters Uiso(H) were set at 1.5 Ueq(C) for the methyl H atoms and at 1.2 Ueq(C) for other H atoms.
Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP (Zsolnai, 1997); software used to prepare material for publication: SHELXL97.
Fig. 1. The molecular structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. |
C21H20Cl2O2 | F(000) = 784 |
Mr = 375.27 | Dx = 1.328 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 25 reflections |
a = 7.635 (2) Å | θ = 2–12° |
b = 12.1814 (15) Å | µ = 0.36 mm−1 |
c = 20.175 (4) Å | T = 293 K |
V = 1876.4 (7) Å3 | Translucent block, colourless |
Z = 4 | 0.2 × 0.2 × 0.1 mm |
Enraf-Nonius CAD-4 diffractometer | 1399 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 25.0°, θmin = 2.0° |
ω–2θ scans | h = 0→9 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→14 |
Tmin = 0.982, Tmax = 0.999 | l = 0→23 |
1904 measured reflections | 3 standard reflections every 100 reflections |
1904 independent reflections | intensity decay: none |
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)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.100 | H-atom parameters constrained |
S = 1.15 | w = 1/[σ2(Fo2) + (0.0344P)2 + 0.6059P] where P = (Fo2 + 2Fc2)/3 |
1904 reflections | (Δ/σ)max < 0.001 |
226 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C21H20Cl2O2 | V = 1876.4 (7) Å3 |
Mr = 375.27 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 7.635 (2) Å | µ = 0.36 mm−1 |
b = 12.1814 (15) Å | T = 293 K |
c = 20.175 (4) Å | 0.2 × 0.2 × 0.1 mm |
Enraf-Nonius CAD-4 diffractometer | 1399 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.000 |
Tmin = 0.982, Tmax = 0.999 | 3 standard reflections every 100 reflections |
1904 measured reflections | intensity decay: none |
1904 independent reflections |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.100 | H-atom parameters constrained |
S = 1.15 | Δρmax = 0.18 e Å−3 |
1904 reflections | Δρmin = −0.18 e Å−3 |
226 parameters |
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 | ||
C1 | 0.8270 (5) | 0.1378 (3) | 0.1271 (2) | 0.0502 (10) | |
C2 | 0.7519 (5) | 0.2517 (3) | 0.13446 (19) | 0.0492 (10) | |
H2 | 0.7735 | 0.2921 | 0.0932 | 0.059* | |
C3 | 0.5512 (5) | 0.2378 (3) | 0.14281 (18) | 0.0468 (10) | |
H3 | 0.5325 | 0.1929 | 0.1825 | 0.056* | |
C4 | 0.4734 (5) | 0.1736 (3) | 0.0836 (2) | 0.0446 (10) | |
H4 | 0.5008 | 0.2124 | 0.0423 | 0.054* | |
C5 | 0.5565 (5) | 0.0586 (3) | 0.0818 (2) | 0.0474 (10) | |
H5 | 0.5385 | 0.0255 | 0.1255 | 0.057* | |
C6 | 0.7571 (5) | 0.0690 (3) | 0.0712 (2) | 0.0510 (11) | |
H6 | 0.7777 | 0.1080 | 0.0295 | 0.061* | |
O7 | 0.9329 (4) | 0.1020 (2) | 0.16662 (14) | 0.0604 (8) | |
C8 | 0.8348 (7) | 0.3150 (4) | 0.1910 (2) | 0.0731 (14) | |
H8A | 0.9584 | 0.3217 | 0.1834 | 0.110* | |
H8B | 0.8151 | 0.2765 | 0.2319 | 0.110* | |
H8C | 0.7833 | 0.3867 | 0.1936 | 0.110* | |
C9 | 0.2779 (6) | 0.1650 (3) | 0.0912 (2) | 0.0497 (10) | |
H9 | 0.2349 | 0.1287 | 0.1283 | 0.060* | |
O10 | 0.1740 (4) | 0.2016 (3) | 0.05289 (15) | 0.0780 (10) | |
C11 | 0.8479 (7) | −0.0420 (4) | 0.0675 (3) | 0.0759 (15) | |
H11A | 0.9712 | −0.0313 | 0.0609 | 0.114* | |
H11B | 0.8007 | −0.0834 | 0.0312 | 0.114* | |
H11C | 0.8291 | −0.0813 | 0.1081 | 0.114* | |
C12 | 0.4603 (5) | 0.3460 (3) | 0.1545 (2) | 0.0520 (10) | |
C13 | 0.4850 (6) | 0.4343 (4) | 0.1119 (2) | 0.0652 (13) | |
H13 | 0.5550 | 0.4251 | 0.0746 | 0.078* | |
C14 | 0.4091 (8) | 0.5351 (4) | 0.1233 (3) | 0.0858 (17) | |
H14 | 0.4296 | 0.5932 | 0.0945 | 0.103* | |
C15 | 0.3021 (8) | 0.5491 (5) | 0.1778 (3) | 0.0923 (19) | |
H15 | 0.2516 | 0.6173 | 0.1860 | 0.111* | |
C16 | 0.2702 (8) | 0.4639 (5) | 0.2197 (3) | 0.0841 (17) | |
H16 | 0.1961 | 0.4734 | 0.2559 | 0.101* | |
C17 | 0.3484 (6) | 0.3629 (4) | 0.2084 (2) | 0.0610 (12) | |
Cl18 | 0.30319 (19) | 0.25791 (13) | 0.26360 (5) | 0.0876 (5) | |
C19 | 0.4697 (6) | −0.0153 (3) | 0.0319 (2) | 0.0499 (10) | |
C20 | 0.3628 (6) | −0.1039 (3) | 0.0498 (2) | 0.0607 (12) | |
C21 | 0.2843 (7) | −0.1714 (4) | 0.0038 (3) | 0.0721 (14) | |
H21 | 0.2145 | −0.2297 | 0.0176 | 0.087* | |
C22 | 0.3096 (8) | −0.1524 (4) | −0.0621 (3) | 0.0839 (16) | |
H22 | 0.2574 | −0.1978 | −0.0934 | 0.101* | |
C23 | 0.4128 (8) | −0.0655 (5) | −0.0822 (3) | 0.0816 (16) | |
H23 | 0.4301 | −0.0524 | −0.1271 | 0.098* | |
C24 | 0.4906 (6) | 0.0021 (4) | −0.0357 (2) | 0.0650 (13) | |
H24 | 0.5586 | 0.0608 | −0.0500 | 0.078* | |
Cl25 | 0.3244 (2) | −0.13281 (11) | 0.13299 (7) | 0.0888 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.034 (2) | 0.057 (2) | 0.060 (2) | −0.006 (2) | 0.002 (2) | 0.011 (2) |
C2 | 0.043 (2) | 0.051 (2) | 0.053 (2) | −0.004 (2) | −0.0024 (18) | 0.004 (2) |
C3 | 0.046 (2) | 0.050 (2) | 0.044 (2) | −0.001 (2) | 0.0023 (18) | 0.000 (2) |
C4 | 0.041 (2) | 0.047 (2) | 0.046 (2) | 0.000 (2) | 0.0023 (18) | 0.006 (2) |
C5 | 0.046 (2) | 0.047 (2) | 0.049 (2) | −0.004 (2) | −0.003 (2) | 0.007 (2) |
C6 | 0.043 (2) | 0.049 (2) | 0.060 (2) | 0.003 (2) | −0.003 (2) | 0.000 (2) |
O7 | 0.0450 (17) | 0.0674 (19) | 0.0687 (18) | 0.0000 (16) | −0.0039 (16) | 0.0130 (16) |
C8 | 0.062 (3) | 0.072 (3) | 0.085 (3) | −0.003 (3) | −0.013 (3) | −0.013 (3) |
C9 | 0.050 (3) | 0.051 (2) | 0.048 (2) | 0.000 (2) | −0.003 (2) | 0.003 (2) |
O10 | 0.0513 (19) | 0.104 (3) | 0.079 (2) | 0.005 (2) | −0.0113 (18) | 0.028 (2) |
C11 | 0.063 (3) | 0.067 (3) | 0.097 (4) | 0.016 (3) | −0.005 (3) | −0.013 (3) |
C12 | 0.046 (2) | 0.056 (3) | 0.053 (2) | −0.005 (2) | −0.001 (2) | −0.014 (2) |
C13 | 0.059 (3) | 0.056 (3) | 0.080 (3) | −0.002 (3) | 0.005 (3) | −0.002 (2) |
C14 | 0.088 (4) | 0.050 (3) | 0.119 (5) | 0.004 (3) | −0.011 (4) | −0.004 (3) |
C15 | 0.073 (4) | 0.070 (4) | 0.134 (5) | 0.013 (3) | −0.016 (4) | −0.047 (4) |
C16 | 0.072 (4) | 0.092 (4) | 0.088 (4) | 0.001 (3) | 0.001 (3) | −0.042 (3) |
C17 | 0.055 (3) | 0.070 (3) | 0.057 (2) | −0.002 (3) | −0.007 (2) | −0.021 (2) |
Cl18 | 0.0821 (9) | 0.1231 (11) | 0.0576 (6) | −0.0011 (10) | 0.0159 (7) | 0.0000 (7) |
C19 | 0.051 (3) | 0.041 (2) | 0.058 (2) | 0.006 (2) | −0.005 (2) | −0.003 (2) |
C20 | 0.065 (3) | 0.046 (2) | 0.071 (3) | 0.008 (2) | −0.010 (3) | −0.002 (2) |
C21 | 0.068 (3) | 0.048 (3) | 0.100 (4) | −0.005 (3) | −0.014 (3) | −0.010 (3) |
C22 | 0.092 (4) | 0.076 (4) | 0.084 (4) | 0.006 (4) | −0.019 (3) | −0.029 (3) |
C23 | 0.098 (4) | 0.087 (4) | 0.060 (3) | 0.012 (4) | −0.012 (3) | −0.009 (3) |
C24 | 0.069 (3) | 0.068 (3) | 0.058 (3) | 0.006 (3) | −0.004 (2) | −0.006 (2) |
Cl25 | 0.1037 (11) | 0.0784 (8) | 0.0842 (8) | −0.0309 (9) | −0.0067 (9) | 0.0221 (7) |
C1—O7 | 1.217 (4) | C11—H11C | 0.96 |
C1—C6 | 1.503 (6) | C12—C13 | 1.389 (6) |
C1—C2 | 1.509 (6) | C12—C17 | 1.399 (6) |
C2—C8 | 1.515 (6) | C13—C14 | 1.377 (6) |
C2—C3 | 1.551 (5) | C13—H13 | 0.93 |
C2—H2 | 0.98 | C14—C15 | 1.380 (8) |
C3—C12 | 1.509 (6) | C14—H14 | 0.93 |
C3—C4 | 1.546 (5) | C15—C16 | 1.361 (7) |
C3—H3 | 0.98 | C15—H15 | 0.93 |
C4—C9 | 1.505 (6) | C16—C17 | 1.386 (7) |
C4—C5 | 1.538 (5) | C16—H16 | 0.93 |
C4—H4 | 0.98 | C17—Cl18 | 1.730 (5) |
C5—C19 | 1.504 (6) | C19—C24 | 1.389 (6) |
C5—C6 | 1.551 (6) | C19—C20 | 1.400 (6) |
C5—H5 | 0.98 | C20—C21 | 1.378 (6) |
C6—C11 | 1.521 (6) | C20—Cl25 | 1.739 (5) |
C6—H6 | 0.98 | C21—C22 | 1.362 (7) |
C8—H8A | 0.96 | C21—H21 | 0.93 |
C8—H8B | 0.96 | C22—C23 | 1.381 (7) |
C8—H8C | 0.96 | C22—H22 | 0.93 |
C9—O10 | 1.193 (4) | C23—C24 | 1.382 (6) |
C9—H9 | 0.93 | C23—H23 | 0.93 |
C11—H11A | 0.96 | C24—H24 | 0.93 |
C11—H11B | 0.96 | ||
O7—C1—C6 | 121.8 (4) | C6—C11—H11A | 109.5 |
O7—C1—C2 | 121.2 (4) | C6—C11—H11B | 109.5 |
C6—C1—C2 | 116.9 (4) | H11A—C11—H11B | 109.5 |
C1—C2—C8 | 112.5 (4) | C6—C11—H11C | 109.5 |
C1—C2—C3 | 106.6 (3) | H11A—C11—H11C | 109.5 |
C8—C2—C3 | 112.7 (4) | H11B—C11—H11C | 109.5 |
C1—C2—H2 | 108.3 | C13—C12—C17 | 116.8 (4) |
C8—C2—H2 | 108.3 | C13—C12—C3 | 121.2 (4) |
C3—C2—H2 | 108.3 | C17—C12—C3 | 122.0 (4) |
C12—C3—C4 | 112.7 (3) | C14—C13—C12 | 122.0 (5) |
C12—C3—C2 | 112.1 (3) | C14—C13—H13 | 119.0 |
C4—C3—C2 | 110.5 (3) | C12—C13—H13 | 119.0 |
C12—C3—H3 | 107.1 | C13—C14—C15 | 119.5 (5) |
C4—C3—H3 | 107.1 | C13—C14—H14 | 120.2 |
C2—C3—H3 | 107.1 | C15—C14—H14 | 120.2 |
C9—C4—C5 | 110.4 (3) | C16—C15—C14 | 120.4 (5) |
C9—C4—C3 | 109.7 (3) | C16—C15—H15 | 119.8 |
C5—C4—C3 | 108.7 (3) | C14—C15—H15 | 119.8 |
C9—C4—H4 | 109.3 | C15—C16—C17 | 119.9 (5) |
C5—C4—H4 | 109.3 | C15—C16—H16 | 120.1 |
C3—C4—H4 | 109.3 | C17—C16—H16 | 120.1 |
C19—C5—C4 | 112.3 (3) | C16—C17—C12 | 121.4 (5) |
C19—C5—C6 | 113.0 (4) | C16—C17—Cl18 | 117.7 (4) |
C4—C5—C6 | 109.6 (3) | C12—C17—Cl18 | 120.9 (4) |
C19—C5—H5 | 107.2 | C24—C19—C20 | 116.0 (4) |
C4—C5—H5 | 107.2 | C24—C19—C5 | 121.0 (4) |
C6—C5—H5 | 107.2 | C20—C19—C5 | 123.0 (4) |
C1—C6—C11 | 111.8 (4) | C21—C20—C19 | 122.6 (4) |
C1—C6—C5 | 107.1 (4) | C21—C20—Cl25 | 117.1 (4) |
C11—C6—C5 | 112.6 (4) | C19—C20—Cl25 | 120.3 (3) |
C1—C6—H6 | 108.4 | C22—C21—C20 | 119.6 (5) |
C11—C6—H6 | 108.4 | C22—C21—H21 | 120.2 |
C5—C6—H6 | 108.4 | C20—C21—H21 | 120.2 |
C2—C8—H8A | 109.5 | C21—C22—C23 | 119.9 (5) |
C2—C8—H8B | 109.5 | C21—C22—H22 | 120.1 |
H8A—C8—H8B | 109.5 | C23—C22—H22 | 120.1 |
C2—C8—H8C | 109.5 | C22—C23—C24 | 120.2 (5) |
H8A—C8—H8C | 109.5 | C22—C23—H23 | 119.9 |
H8B—C8—H8C | 109.5 | C24—C23—H23 | 119.9 |
O10—C9—C4 | 124.6 (4) | C23—C24—C19 | 121.7 (5) |
O10—C9—H9 | 117.7 | C23—C24—H24 | 119.1 |
C4—C9—H9 | 117.7 | C19—C24—H24 | 119.1 |
O7—C1—C2—C8 | 5.0 (5) | C4—C3—C12—C17 | 107.6 (4) |
C6—C1—C2—C8 | −178.5 (4) | C2—C3—C12—C17 | −127.0 (4) |
O7—C1—C2—C3 | −119.0 (4) | C17—C12—C13—C14 | 2.4 (7) |
C6—C1—C2—C3 | 57.4 (5) | C3—C12—C13—C14 | −177.2 (4) |
C1—C2—C3—C12 | 176.9 (3) | C12—C13—C14—C15 | −1.3 (8) |
C8—C2—C3—C12 | 52.9 (5) | C13—C14—C15—C16 | −0.7 (9) |
C1—C2—C3—C4 | −56.5 (4) | C14—C15—C16—C17 | 1.4 (9) |
C8—C2—C3—C4 | 179.6 (3) | C15—C16—C17—C12 | −0.1 (8) |
C12—C3—C4—C9 | −51.4 (4) | C15—C16—C17—Cl18 | 179.8 (4) |
C2—C3—C4—C9 | −177.7 (4) | C13—C12—C17—C16 | −1.8 (7) |
C12—C3—C4—C5 | −172.2 (3) | C3—C12—C17—C16 | 177.9 (4) |
C2—C3—C4—C5 | 61.5 (4) | C13—C12—C17—Cl18 | 178.3 (3) |
C9—C4—C5—C19 | 51.3 (5) | C3—C12—C17—Cl18 | −2.0 (6) |
C3—C4—C5—C19 | 171.7 (3) | C4—C5—C19—C24 | 70.6 (5) |
C9—C4—C5—C6 | 177.8 (3) | C6—C5—C19—C24 | −54.1 (5) |
C3—C4—C5—C6 | −61.8 (4) | C4—C5—C19—C20 | −108.7 (4) |
O7—C1—C6—C11 | −5.7 (6) | C6—C5—C19—C20 | 126.6 (4) |
C2—C1—C6—C11 | 177.8 (4) | C24—C19—C20—C21 | 0.9 (7) |
O7—C1—C6—C5 | 118.0 (4) | C5—C19—C20—C21 | −179.8 (4) |
C2—C1—C6—C5 | −58.4 (5) | C24—C19—C20—Cl25 | −179.1 (3) |
C19—C5—C6—C1 | −176.0 (3) | C5—C19—C20—Cl25 | 0.1 (6) |
C4—C5—C6—C1 | 57.9 (4) | C19—C20—C21—C22 | −0.2 (7) |
C19—C5—C6—C11 | −52.7 (5) | Cl25—C20—C21—C22 | 179.8 (4) |
C4—C5—C6—C11 | −178.9 (4) | C20—C21—C22—C23 | −0.3 (8) |
C5—C4—C9—O10 | −121.3 (5) | C21—C22—C23—C24 | 0.0 (8) |
C3—C4—C9—O10 | 118.9 (5) | C22—C23—C24—C19 | 0.7 (8) |
C4—C3—C12—C13 | −72.8 (5) | C20—C19—C24—C23 | −1.2 (7) |
C2—C3—C12—C13 | 52.7 (5) | C5—C19—C24—C23 | 179.5 (4) |
Experimental details
Crystal data | |
Chemical formula | C21H20Cl2O2 |
Mr | 375.27 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 293 |
a, b, c (Å) | 7.635 (2), 12.1814 (15), 20.175 (4) |
V (Å3) | 1876.4 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.36 |
Crystal size (mm) | 0.2 × 0.2 × 0.1 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.982, 0.999 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1904, 1904, 1399 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.594 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.100, 1.15 |
No. of reflections | 1904 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.18 |
Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, MolEN (Fair, 1990), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ZORTEP (Zsolnai, 1997), SHELXL97.
C6—C1—C2—C3 | 57.4 (5) | C3—C4—C5—C6 | −61.8 (4) |
C1—C2—C3—C4 | −56.5 (4) | C2—C1—C6—C5 | −58.4 (5) |
C2—C3—C4—C5 | 61.5 (4) | C4—C5—C6—C1 | 57.9 (4) |
During attempts to prepare a pyran derivative by the Michael condensation of diethyl ketone and o-chlorobenzaldehyde, an unexpected product, the title compound, (I), was obtained as a minor product. The present investigation was undertaken to ascertain the structure and conformation of (I), since they cannot be assigned conclusively from 1H NMR data.
The cyclohexane ring is in a chair conformation, as shown by the torsion angles (Table 1) around the C—C bonds involving the six C atoms (C1–C6). The torsion angles deviate from the angle of 56° expected for a perfect chair conformation (Kalsi, 1997) as a result of the sp2-hybridized atom C1. The bond lengths and angles within the cyclohexane ring are in the ranges 1.503 (6)—1.551 (6) Å and 106.6 (3)–116.9 (4)°, respectively. The equatorial orientations of all the substituents are confirmed by the torsion angles of about 180° formed by the external atom and the other three ring atoms. The dihedral angle between the planes of the phenyl rings is 61.9 (2)°. The chair conformation observed in (I) is comparable to that observed in the thioketal of N-methyl-2,6-diphenyl-3-isopropylpiperdin-4-one (Sujatha, 1995), but contrasts with the twist-boat conformation of the N-nitroso derivative of 2,6-bis(2-chlorophenyl-3,5-dimethylpiperidin-4-one (Sukumar et al., 1993). Atoms O10, C9, C4, O7 and C1 are coplanar with the maximum deviation being 0.014 (2) Å for O10; the molecule is nearly symmetrical with respect to the above plane.
The crystal structure is stabilized by C—H···O interactions, the most significant of which are (C9)H9···O7(−1 + x, y, z) and (C16)H16···O7(1 − x, 0.5 + y, 0.5 − z) with H···O distances of 2.45 and 2.42 Å, and C—H···O angles of 130.5 and 146.5°, respectively, around the corresponding H atoms. The former interactions contribute to the chain formation along the a axis; the chains are interlinked by the latter interactions. Another intermolecular interaction prevails between atoms C4 and O10(0.5 + x, 0.5 − y, −z) through atom H4, with a distance of 2.56 Å with an angle of 161.2° around H4. The formation of (I), although unexpected, can be explained by the condensation of the dibenzylideneacetone derivative formed in situ with the acetaldehyde present in ethanol.