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The molecular structure of the title compound, C21H24O2, reveals a chair conformation for the pyran ring, in which the methyl and p-tolyl groups occupy equatorial positions. A C—H...π interaction is observed between an H atom of the tetra­hydro­pyran ring and one of the aromatic rings.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803005336/ci6198sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803005336/ci6198Isup2.hkl
Contains datablock I

CCDC reference: 209948

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.007 Å
  • R factor = 0.074
  • wR factor = 0.198
  • Data-to-parameter ratio = 14.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

Pyran-4-one derivatives are numerous, naturally occurring and biologically active (Noller, 1966). Several substituted tetrahydropyran-4-one derivatives are easily synthesized (Japp & Maitland, 1904). Saturated and partially saturated pyrans can assume different conformations depending on the level of unsaturation and the nature of the substituents in the ring, viz. planar (Kumar et al., 1999), twist boat (Usman et al., 2002), sofa (Ray et al., 1998) or chair (Belakhov et al., 2002) conformation. Our interest in this class of compounds stems from their structures, conformations and their possible biological functions.

The saturated pyran ring in the title molecule, (I), is in a chair conformation, as shown by the torsion angles around the bonds involving the ring atoms (Table 1). The torsion angles deviate from the value of 56° expected for a perfect chair conformation (Kalsi, 1997). Within the p-tolyl group, the ranges of bond lengths and angles are 1.371 (7)–1.389 (6) Å and 117.3 (4)–121.9 (4)°, respectively. The equatorial dispositions of methyl and p-tolyl groups are revealed by the C7—C3—C2—O1, C9—C5—C6—O1, C10—C2—O1—C6 and C16—C6—O1—C2 torsion angles of 173.5 (4), 178.0 (4), 178.5 (4) and −172.5 (4)°, respectively; the ideal value for these angles, being 180° (Nasipuri, 1992). The methyl substituents on C3 and C5 are nearly parallel to the carbonyl group (McCullough et al., 1999), as reaveled by the corresponding torsion angles which are close to 0°. The chiral atoms C2, C3, C5 and C6 adopt R, S, R and S configurations, respectively. The gas-phase conformation obtained through AM1 calculations (Stewart, 1990) is very similar to that observed in the solid state. The inherent molecular stability of the compound is revealed by its calculated heat of formation of −49.7 kcal mol−1. In the crystal structure, the molecules are aggregated into corrugated layers and one of the phenyl rings is involved in a C—H···π interaction [H3···CgA = 2.71 Å, C3···CgA = 3.623 (6) Å and C3—H3···CgA 155°, where is CgA is the phenyl ring (C16–C21) at (−1/2 + x, 1/2 − y, 1 − z).

Experimental top

The title compound was obtained by the condensation of pentan-3-one and p-tolualdehyde in a 1:2 molar ratio in ethanol, as reported in the literature (Baliah & Mangalam, 1978). Diffraction-quality crystals were obtained by recrystallization of the crude product from ethanol.

Refinement top

The reflection (020) was removed during the refinement as the observed and calculated structure factors showed very large disagreement. The reflections (5,19,7) and (5,6,12) were also removed as they fit badly.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 1998); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. One of the methyl H atoms is hidden.
r-2,c-6-Di(p-tolyl)-t-3,t-5-dimethyltetrahydropyran-4-one top
Crystal data top
C21H24O2Dx = 1.152 Mg m3
Mr = 308.40Melting point: 413-414 K K
Orthorhombic, PbcaCu Kα radiation, λ = 1.54180 Å
Hall symbol: -P 2ac 2abCell parameters from 25 reflections
a = 9.0894 (18) Åθ = 2–12°
b = 25.813 (3) ŵ = 0.57 mm1
c = 15.1605 (10) ÅT = 293 K
V = 3557.0 (8) Å3Non-transparent plate, colourless
Z = 80.2 × 0.2 × 0.1 mm
F(000) = 1328
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.000
Radiation source: fine-focus sealed tubeθmax = 67.9°, θmin = 4.5°
Graphite monochromatorh = 100
ω–2θ scansk = 031
3094 measured reflectionsl = 018
3094 independent reflections3 standard reflections every 10 reflections
1561 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.074Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.198H-atom parameters constrained
S = 1.11 w = 1/[σ2(Fo2) + (0.0255P)2 + 7.7276P]
where P = (Fo2 + 2Fc2)/3
3094 reflections(Δ/σ)max < 0.001
212 parametersΔρmax = 0.18 e Å3
0 restraintsΔρmin = 0.25 e Å3
Crystal data top
C21H24O2V = 3557.0 (8) Å3
Mr = 308.40Z = 8
Orthorhombic, PbcaCu Kα radiation
a = 9.0894 (18) ŵ = 0.57 mm1
b = 25.813 (3) ÅT = 293 K
c = 15.1605 (10) Å0.2 × 0.2 × 0.1 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.000
3094 measured reflections3 standard reflections every 10 reflections
3094 independent reflections intensity decay: none
1561 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0740 restraints
wR(F2) = 0.198H-atom parameters constrained
S = 1.11Δρmax = 0.18 e Å3
3094 reflectionsΔρmin = 0.25 e Å3
212 parameters
Special details top

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. The asymmetric unit of the cell consists of twenty three non-hydrogen atoms which were anisotropically refined using the atomic scattering factors given in SHELX97 program. All the hydrogen atoms were included in their calculated positions. The thermal parameters of H atoms of methyl groups were fixed as 1.5 Ueq of their respective carbon atoms while those of other hydrogen atoms were fixed as 1.2 Ueq of their corresponding carrier atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.3386 (3)0.21722 (10)0.47826 (19)0.0501 (8)
C20.3436 (6)0.16638 (16)0.4427 (3)0.0517 (12)
H20.42470.16440.40020.062*
C30.1986 (6)0.15250 (17)0.3952 (3)0.0549 (13)
H30.12250.14910.44060.066*
C40.1514 (6)0.19571 (19)0.3344 (3)0.0566 (13)
C50.1592 (5)0.24947 (17)0.3730 (3)0.0495 (11)
H50.08700.25140.42090.059*
C60.3134 (5)0.25661 (16)0.4140 (3)0.0487 (12)
H60.38750.25350.36740.058*
C70.2087 (8)0.10035 (19)0.3475 (4)0.089 (2)
H7A0.12120.09500.31320.133*
H7B0.21820.07310.39010.133*
H7C0.29290.10030.30930.133*
O80.1122 (5)0.18778 (14)0.2588 (2)0.0834 (13)
C90.1202 (7)0.2911 (2)0.3056 (3)0.0806 (18)
H9A0.18980.29020.25800.121*
H9B0.12310.32450.33340.121*
H9C0.02320.28480.28310.121*
C100.3748 (5)0.12970 (17)0.5178 (3)0.0494 (12)
C110.4746 (6)0.08991 (19)0.5096 (4)0.0666 (15)
H110.52600.08590.45700.080*
C120.4997 (7)0.05590 (19)0.5778 (4)0.0756 (17)
H120.56790.02940.57050.091*
C130.4261 (7)0.06040 (19)0.6564 (3)0.0634 (15)
C140.3242 (6)0.09967 (19)0.6647 (3)0.0642 (15)
H140.27160.10300.71700.077*
C150.2988 (6)0.13430 (19)0.5962 (3)0.0594 (14)
H150.23020.16070.60330.071*
C160.3312 (5)0.30789 (16)0.4588 (3)0.0465 (11)
C170.3906 (6)0.34989 (17)0.4157 (3)0.0542 (13)
H170.42510.34580.35840.065*
C180.4003 (6)0.39790 (19)0.4551 (3)0.0623 (14)
H180.44160.42540.42410.075*
C190.3495 (6)0.40571 (18)0.5401 (3)0.0588 (13)
C200.2935 (6)0.36365 (19)0.5842 (3)0.0596 (14)
H200.26140.36770.64210.072*
C210.2836 (5)0.31543 (17)0.5449 (3)0.0530 (13)
H210.24470.28770.57650.064*
C220.4543 (8)0.0228 (2)0.7318 (4)0.100 (2)
H22A0.47570.01090.70830.150*
H22B0.36860.02090.76860.150*
H22C0.53650.03480.76600.150*
C230.3542 (7)0.45915 (19)0.5817 (4)0.088 (2)
H23A0.32560.45680.64250.132*
H23B0.28760.48170.55110.132*
H23C0.45220.47280.57790.132*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.061 (2)0.0414 (16)0.0483 (17)0.0015 (15)0.0067 (17)0.0009 (14)
C20.055 (3)0.048 (3)0.052 (3)0.004 (2)0.005 (2)0.003 (2)
C30.068 (4)0.050 (3)0.047 (3)0.012 (3)0.000 (3)0.004 (2)
C40.054 (3)0.072 (3)0.043 (3)0.005 (3)0.002 (3)0.007 (2)
C50.053 (3)0.053 (3)0.042 (2)0.002 (3)0.001 (2)0.004 (2)
C60.053 (3)0.050 (3)0.043 (2)0.002 (2)0.003 (2)0.004 (2)
C70.128 (6)0.055 (3)0.083 (4)0.005 (4)0.013 (4)0.021 (3)
O80.113 (3)0.088 (2)0.049 (2)0.001 (3)0.019 (2)0.016 (2)
C90.087 (5)0.080 (4)0.075 (4)0.008 (4)0.023 (3)0.006 (3)
C100.052 (3)0.044 (2)0.053 (3)0.003 (2)0.001 (2)0.002 (2)
C110.069 (4)0.056 (3)0.075 (4)0.006 (3)0.014 (3)0.005 (3)
C120.089 (5)0.048 (3)0.090 (4)0.015 (3)0.002 (4)0.010 (3)
C130.082 (4)0.047 (3)0.062 (3)0.009 (3)0.021 (3)0.006 (3)
C140.077 (4)0.063 (3)0.053 (3)0.004 (3)0.005 (3)0.002 (3)
C150.062 (4)0.059 (3)0.057 (3)0.010 (3)0.000 (3)0.001 (3)
C160.052 (3)0.044 (2)0.043 (2)0.001 (2)0.003 (2)0.006 (2)
C170.064 (3)0.055 (3)0.044 (2)0.009 (3)0.007 (3)0.003 (2)
C180.069 (4)0.051 (3)0.066 (3)0.011 (3)0.001 (3)0.006 (3)
C190.063 (4)0.052 (3)0.062 (3)0.001 (3)0.005 (3)0.006 (2)
C200.068 (4)0.064 (3)0.046 (3)0.002 (3)0.009 (3)0.002 (2)
C210.065 (3)0.047 (3)0.048 (3)0.001 (2)0.005 (3)0.005 (2)
C220.136 (6)0.077 (4)0.087 (5)0.000 (4)0.026 (5)0.028 (4)
C230.111 (5)0.057 (3)0.096 (4)0.001 (4)0.005 (4)0.024 (3)
Geometric parameters (Å, º) top
O1—C21.419 (5)C12—C131.371 (7)
O1—C61.427 (5)C12—H120.93
C2—C101.508 (6)C13—C141.379 (7)
C2—C31.545 (6)C13—C221.521 (7)
C2—H20.98C14—C151.389 (6)
C3—C41.509 (6)C14—H140.93
C3—C71.530 (6)C15—H150.93
C3—H30.98C16—C171.376 (6)
C4—O81.218 (5)C16—C211.389 (6)
C4—C51.508 (6)C17—C181.378 (6)
C5—C91.525 (6)C17—H170.93
C5—C61.544 (6)C18—C191.384 (6)
C5—H50.98C18—H180.93
C6—C161.496 (6)C19—C201.373 (6)
C6—H60.98C19—C231.517 (6)
C7—H7A0.96C20—C211.383 (6)
C7—H7B0.96C20—H200.93
C7—H7C0.96C21—H210.93
C9—H9A0.96C22—H22A0.96
C9—H9B0.96C22—H22B0.96
C9—H9C0.96C22—H22C0.96
C10—C111.376 (6)C23—H23A0.96
C10—C151.380 (6)C23—H23B0.96
C11—C121.375 (7)C23—H23C0.96
C11—H110.93
C2—O1—C6113.9 (3)C12—C11—H11119.4
O1—C2—C10107.4 (4)C10—C11—H11119.4
O1—C2—C3111.4 (4)C13—C12—C11121.2 (5)
C10—C2—C3111.5 (4)C13—C12—H12119.4
O1—C2—H2108.8C11—C12—H12119.4
C10—C2—H2108.8C12—C13—C14118.0 (5)
C3—C2—H2108.8C12—C13—C22121.1 (5)
C4—C3—C7112.3 (4)C14—C13—C22120.9 (5)
C4—C3—C2110.8 (4)C13—C14—C15121.1 (5)
C7—C3—C2111.9 (4)C13—C14—H14119.4
C4—C3—H3107.2C15—C14—H14119.4
C7—C3—H3107.2C10—C15—C14120.3 (5)
C2—C3—H3107.2C10—C15—H15119.8
O8—C4—C5122.3 (5)C14—C15—H15119.8
O8—C4—C3122.2 (5)C17—C16—C21117.3 (4)
C5—C4—C3115.5 (4)C17—C16—C6121.6 (4)
C4—C5—C9112.2 (4)C21—C16—C6121.1 (4)
C4—C5—C6108.0 (4)C16—C17—C18121.9 (4)
C9—C5—C6113.4 (4)C16—C17—H17119.1
C4—C5—H5107.7C18—C17—H17119.1
C9—C5—H5107.7C17—C18—C19120.9 (5)
C6—C5—H5107.7C17—C18—H18119.6
O1—C6—C16107.7 (3)C19—C18—H18119.6
O1—C6—C5109.6 (4)C20—C19—C18117.5 (5)
C16—C6—C5112.7 (4)C20—C19—C23121.8 (5)
O1—C6—H6108.9C18—C19—C23120.7 (5)
C16—C6—H6108.9C19—C20—C21121.7 (4)
C5—C6—H6108.9C19—C20—H20119.1
C3—C7—H7A109.5C21—C20—H20119.1
C3—C7—H7B109.5C20—C21—C16120.7 (4)
H7A—C7—H7B109.5C20—C21—H21119.6
C3—C7—H7C109.5C16—C21—H21119.6
H7A—C7—H7C109.5C13—C22—H22A109.5
H7B—C7—H7C109.5C13—C22—H22B109.5
C5—C9—H9A109.5H22A—C22—H22B109.5
C5—C9—H9B109.5C13—C22—H22C109.5
H9A—C9—H9B109.5H22A—C22—H22C109.5
C5—C9—H9C109.5H22B—C22—H22C109.5
H9A—C9—H9C109.5C19—C23—H23A109.5
H9B—C9—H9C109.5C19—C23—H23B109.5
C11—C10—C15118.2 (5)H23A—C23—H23B109.5
C11—C10—C2121.6 (5)C19—C23—H23C109.5
C15—C10—C2120.2 (4)H23A—C23—H23C109.5
C12—C11—C10121.2 (5)H23B—C23—H23C109.5
C6—O1—C2—C10178.5 (4)C15—C10—C11—C120.8 (8)
C6—O1—C2—C359.1 (5)C2—C10—C11—C12178.4 (5)
O1—C2—C3—C447.3 (5)C10—C11—C12—C130.1 (9)
C10—C2—C3—C4167.3 (4)C11—C12—C13—C140.9 (9)
O1—C2—C3—C7173.5 (4)C11—C12—C13—C22179.8 (5)
C10—C2—C3—C766.5 (5)C12—C13—C14—C151.2 (8)
C7—C3—C4—O86.9 (8)C22—C13—C14—C15179.5 (5)
C2—C3—C4—O8132.9 (5)C11—C10—C15—C140.5 (8)
C7—C3—C4—C5171.8 (5)C2—C10—C15—C14178.1 (4)
C2—C3—C4—C545.8 (6)C13—C14—C15—C100.6 (8)
O8—C4—C5—C92.8 (7)O1—C6—C16—C17144.9 (4)
C3—C4—C5—C9176.0 (5)C5—C6—C16—C1794.1 (5)
O8—C4—C5—C6128.4 (5)O1—C6—C16—C2137.4 (6)
C3—C4—C5—C650.3 (5)C5—C6—C16—C2183.6 (5)
C2—O1—C6—C16172.5 (4)C21—C16—C17—C181.3 (8)
C2—O1—C6—C564.6 (5)C6—C16—C17—C18176.6 (5)
C4—C5—C6—O157.1 (5)C16—C17—C18—C190.4 (8)
C9—C5—C6—O1178.0 (4)C17—C18—C19—C201.9 (8)
C4—C5—C6—C16177.0 (4)C17—C18—C19—C23177.3 (5)
C9—C5—C6—C1658.1 (5)C18—C19—C20—C211.9 (8)
O1—C2—C10—C11136.5 (5)C23—C19—C20—C21177.3 (5)
C3—C2—C10—C11101.3 (5)C19—C20—C21—C160.3 (8)
O1—C2—C10—C1546.0 (6)C17—C16—C21—C201.3 (7)
C3—C2—C10—C1576.3 (5)C6—C16—C21—C20176.6 (5)

Experimental details

Crystal data
Chemical formulaC21H24O2
Mr308.40
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)293
a, b, c (Å)9.0894 (18), 25.813 (3), 15.1605 (10)
V3)3557.0 (8)
Z8
Radiation typeCu Kα
µ (mm1)0.57
Crystal size (mm)0.2 × 0.2 × 0.1
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3094, 3094, 1561
Rint0.000
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.074, 0.198, 1.11
No. of reflections3094
No. of parameters212
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.18, 0.25

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, MolEN (Fair, 1990), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 1998), SHELXL97.

Selected geometric parameters (Å, º) top
O1—C21.419 (5)C4—O81.218 (5)
O1—C61.427 (5)C4—C51.508 (6)
C2—C101.508 (6)C5—C91.525 (6)
C2—C31.545 (6)C5—C61.544 (6)
C3—C41.509 (6)C6—C161.496 (6)
C3—C71.530 (6)
C2—O1—C6113.9 (3)C5—C4—C3115.5 (4)
O1—C2—C3111.4 (4)C4—C5—C6108.0 (4)
C4—C3—C2110.8 (4)O1—C6—C5109.6 (4)
C6—O1—C2—C359.1 (5)C3—C4—C5—C650.3 (5)
O1—C2—C3—C447.3 (5)C2—O1—C6—C564.6 (5)
C2—C3—C4—C545.8 (6)C4—C5—C6—O157.1 (5)
 

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