Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807050660/om2166sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807050660/om2166Isup2.hkl |
CCDC reference: 667398
The title compound was obtained by the condensation of pentan-3-one and p-bromo benzaldehyde in a 1:2 molar ratio in ethanol by adopting the literature procedure for similar types of compounds (Baliah & Mangalam, 1978). Diffraction quality crystals were obtained by recrystallization of the obtained compound in ethanol.
All the hydrogen atoms were fixed geometrically and allowed to ride on the parent carbon atoms, with aromatic C—H = 0.93 Å, aliphatic C—H = 0.98 Å and methyl C—H = 0.96 Å. The displacement parameters were set for phenyl and aliphatic H atoms at Uiso(H) = 1.2Ueq(C) and for methyl H atoms at 1.5Ueq(C).
Pyran-4-one derivatives are very important, naturally available and biologically active six-membered heterocyclic compounds (Noller, 1966). Japp and Maitland were the first to report the synthesis of several substituted tetrahydropyran derivatives (Japp & Maitland, 1904). While reviewing the literature, depending upon the number and nature of the substituents and the level of unsaturation, different conformations are reported for the six-membered heterocyclic ring, namely, sofa (Ray et al., 1998), planar (Kumar et al., 1999), chair (Belakhov et al., 2002; Krishnamoorthy et al., 2003; Jose Kavitha et al., 2003) or twist boat (Usman et al., 2002). Moreover, the synthesized compound contains two pairs of chiral carbons with identical groups on each. According to Eliel, there can be four racemic and two meso forms (Eliel, 1962).
In the title compound C19H18Br2O2, as shown in Fig. 1, the tetrahydropyran ring adopts a chair conformation. Both the methyl groups and p-Br phenyl rings occupy equatorial positions. Similar kinds of compounds with p-Cl or p-CH3 substituents reported earlier exist in the chair conformation with equatorial orientations of all the phenyl and methyl groups. The absolute configuration of the chiral atoms C1, C2, C4 and C5 are S, R, S and R, respectively.
The crystal structure is stabilized by intermolecular C—H···O, C—H···π and Br···Br interactions. These contacts facilitate the formation of a zigzag network extendend over the ac plane. In the crystal structure the adjacent layers are linked through C—H···π interactions, viz. C4—H4···Cgi with H4···Cgi = 2.766 Å, C4···Cgi = 3.687 Å and C4—H4···Cgi = 156°, where Cgi denotes the centroid of the C12–C17 aryl ring of the molecule (symmetry code: i = 2 - x, 1/2 + y, 3/2 - z).
The molecules are also held together by C—H···O interactions between C14 and O1ii of 3.403 (5) Å, C14—H14···O1ii = 136°, symmetry code: ii = 1/2 + x, y, 3/2 - z. A short contact is also seen between Br1···Br2iii (3.4756 (9) Å, symmetry code: iii = 5/2 - x,-y,-1/2 + z).
For related literature, see: Baliah & Mangalam (1978); Belakhov et al. (2002); Eliel (1962); Japp & Maitland (1904); Jose Kavitha et al. (2003); Krishnamoorthy et al. (2003); Kumar et al. (1999); Noller (1966); Ray et al. (1998); Usman et al. (2002).
Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
C19H18Br2O2 | F(000) = 1744 |
Mr = 438.15 | Dx = 1.605 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 5214 reflections |
a = 15.146 (3) Å | θ = 2.1–26.0° |
b = 9.1460 (18) Å | µ = 4.48 mm−1 |
c = 26.180 (5) Å | T = 297 K |
V = 3626.6 (12) Å3 | Rectangular, colourless |
Z = 8 | 0.22 × 0.20 × 0.19 mm |
Bruker Kappa-APEXII CCD area-detector diffractometer | 3450 independent reflections |
Radiation source: fine-focus sealed tube | 2171 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.047 |
φ and ω scans | θmax = 26.0°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −17→17 |
Tmin = 0.439, Tmax = 0.483 | k = −10→10 |
38553 measured reflections | l = −32→29 |
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)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.094 | H-atom parameters constrained |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0317P)2 + 4.4775P] where P = (Fo2 + 2Fc2)/3 |
3450 reflections | (Δ/σ)max = 0.002 |
210 parameters | Δρmax = 0.62 e Å−3 |
0 restraints | Δρmin = −0.41 e Å−3 |
C19H18Br2O2 | V = 3626.6 (12) Å3 |
Mr = 438.15 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 15.146 (3) Å | µ = 4.48 mm−1 |
b = 9.1460 (18) Å | T = 297 K |
c = 26.180 (5) Å | 0.22 × 0.20 × 0.19 mm |
Bruker Kappa-APEXII CCD area-detector diffractometer | 3450 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 2171 reflections with I > 2σ(I) |
Tmin = 0.439, Tmax = 0.483 | Rint = 0.047 |
38553 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.094 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.62 e Å−3 |
3450 reflections | Δρmin = −0.41 e Å−3 |
210 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 | ||
Br1 | 1.23772 (3) | 0.02246 (7) | 0.981200 (17) | 0.0872 (2) | |
Br2 | 1.08186 (3) | 0.16048 (6) | 0.532667 (17) | 0.08003 (19) | |
C1 | 0.9071 (2) | 0.1921 (4) | 0.74443 (12) | 0.0387 (8) | |
H1 | 0.8595 | 0.1200 | 0.7473 | 0.046* | |
C2 | 0.8682 (2) | 0.3470 (4) | 0.75042 (13) | 0.0460 (9) | |
H2 | 0.9174 | 0.4165 | 0.7488 | 0.055* | |
C3 | 0.8285 (2) | 0.3578 (4) | 0.80309 (14) | 0.0484 (9) | |
C4 | 0.8888 (2) | 0.3119 (4) | 0.84640 (13) | 0.0459 (9) | |
H4 | 0.9356 | 0.3856 | 0.8489 | 0.055* | |
C5 | 0.9333 (2) | 0.1659 (4) | 0.83367 (12) | 0.0402 (8) | |
H5 | 0.8891 | 0.0879 | 0.8357 | 0.048* | |
C6 | 1.0073 (2) | 0.1311 (4) | 0.86997 (12) | 0.0407 (8) | |
C7 | 0.9971 (3) | 0.0304 (4) | 0.90867 (13) | 0.0518 (10) | |
H7 | 0.9431 | −0.0168 | 0.9125 | 0.062* | |
C8 | 1.0649 (3) | −0.0019 (4) | 0.94173 (14) | 0.0592 (11) | |
H8 | 1.0572 | −0.0709 | 0.9675 | 0.071* | |
C9 | 1.1438 (3) | 0.0689 (5) | 0.93619 (13) | 0.0532 (10) | |
C10 | 1.1559 (2) | 0.1721 (4) | 0.89904 (14) | 0.0550 (10) | |
H10 | 1.2094 | 0.2212 | 0.8962 | 0.066* | |
C11 | 1.0871 (2) | 0.2026 (4) | 0.86575 (14) | 0.0496 (9) | |
H11 | 1.0950 | 0.2722 | 0.8402 | 0.059* | |
C12 | 0.9531 (2) | 0.1727 (4) | 0.69389 (12) | 0.0384 (8) | |
C13 | 1.0388 (2) | 0.2201 (4) | 0.68676 (14) | 0.0463 (9) | |
H13 | 1.0703 | 0.2579 | 0.7143 | 0.056* | |
C14 | 1.0784 (2) | 0.2121 (4) | 0.63948 (15) | 0.0512 (10) | |
H14 | 1.1362 | 0.2437 | 0.6350 | 0.061* | |
C15 | 1.0313 (3) | 0.1570 (4) | 0.59899 (14) | 0.0502 (10) | |
C16 | 0.9471 (3) | 0.1062 (4) | 0.60490 (14) | 0.0509 (10) | |
H16 | 0.9163 | 0.0677 | 0.5773 | 0.061* | |
C17 | 0.9086 (2) | 0.1129 (4) | 0.65277 (13) | 0.0458 (9) | |
H17 | 0.8518 | 0.0766 | 0.6574 | 0.055* | |
C18 | 0.8418 (3) | 0.3087 (5) | 0.89754 (15) | 0.0745 (13) | |
H18A | 0.8107 | 0.3990 | 0.9025 | 0.112* | |
H18B | 0.8843 | 0.2960 | 0.9244 | 0.112* | |
H18C | 0.8006 | 0.2289 | 0.8981 | 0.112* | |
C19 | 0.8032 (3) | 0.3881 (5) | 0.70866 (16) | 0.0738 (13) | |
H19A | 0.7555 | 0.3189 | 0.7082 | 0.111* | |
H19B | 0.8327 | 0.3873 | 0.6762 | 0.111* | |
H19C | 0.7802 | 0.4841 | 0.7152 | 0.111* | |
O1 | 0.75334 (19) | 0.3972 (4) | 0.81016 (11) | 0.0765 (9) | |
O2 | 0.97028 (14) | 0.1662 (2) | 0.78362 (8) | 0.0409 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0670 (3) | 0.1321 (5) | 0.0623 (3) | 0.0304 (3) | −0.0187 (2) | 0.0014 (3) |
Br2 | 0.0892 (4) | 0.0904 (4) | 0.0605 (3) | 0.0113 (3) | 0.0319 (2) | 0.0005 (2) |
C1 | 0.0311 (19) | 0.043 (2) | 0.0426 (19) | −0.0031 (16) | −0.0013 (15) | 0.0015 (16) |
C2 | 0.036 (2) | 0.047 (2) | 0.055 (2) | 0.0024 (17) | 0.0000 (17) | 0.0033 (19) |
C3 | 0.034 (2) | 0.049 (2) | 0.062 (2) | 0.0027 (18) | 0.0028 (17) | −0.0037 (18) |
C4 | 0.039 (2) | 0.050 (2) | 0.050 (2) | 0.0006 (18) | 0.0024 (16) | −0.0097 (17) |
C5 | 0.036 (2) | 0.044 (2) | 0.0406 (19) | −0.0080 (17) | 0.0015 (15) | 0.0008 (16) |
C6 | 0.045 (2) | 0.039 (2) | 0.0380 (18) | −0.0010 (17) | −0.0004 (16) | −0.0036 (17) |
C7 | 0.054 (2) | 0.054 (2) | 0.048 (2) | −0.013 (2) | −0.0010 (18) | 0.0052 (19) |
C8 | 0.069 (3) | 0.066 (3) | 0.043 (2) | 0.004 (2) | −0.001 (2) | 0.0091 (19) |
C9 | 0.054 (3) | 0.068 (3) | 0.037 (2) | 0.015 (2) | −0.0064 (18) | −0.008 (2) |
C10 | 0.036 (2) | 0.068 (3) | 0.062 (2) | −0.001 (2) | −0.0012 (18) | −0.001 (2) |
C11 | 0.043 (2) | 0.055 (2) | 0.050 (2) | −0.003 (2) | 0.0003 (18) | 0.0107 (18) |
C12 | 0.0322 (19) | 0.038 (2) | 0.0447 (19) | 0.0023 (16) | −0.0010 (15) | 0.0031 (16) |
C13 | 0.035 (2) | 0.054 (2) | 0.050 (2) | −0.0040 (18) | −0.0035 (17) | 0.0031 (18) |
C14 | 0.033 (2) | 0.058 (2) | 0.063 (3) | −0.0003 (19) | 0.0070 (19) | 0.007 (2) |
C15 | 0.049 (2) | 0.050 (2) | 0.051 (2) | 0.011 (2) | 0.0112 (18) | 0.0035 (19) |
C16 | 0.054 (3) | 0.053 (2) | 0.046 (2) | 0.003 (2) | −0.0053 (18) | −0.0061 (18) |
C17 | 0.036 (2) | 0.053 (2) | 0.048 (2) | −0.0065 (18) | 0.0000 (16) | −0.0035 (18) |
C18 | 0.061 (3) | 0.107 (4) | 0.055 (2) | 0.019 (3) | 0.010 (2) | −0.011 (2) |
C19 | 0.068 (3) | 0.087 (3) | 0.066 (3) | 0.032 (3) | −0.006 (2) | 0.008 (2) |
O1 | 0.0427 (17) | 0.108 (3) | 0.0783 (19) | 0.0243 (17) | 0.0096 (15) | 0.0015 (18) |
O2 | 0.0334 (13) | 0.0489 (15) | 0.0403 (12) | 0.0071 (11) | −0.0021 (10) | −0.0006 (11) |
Br1—C9 | 1.895 (4) | C8—H8 | 0.9300 |
Br2—C15 | 1.898 (3) | C9—C10 | 1.368 (5) |
C1—O2 | 1.422 (4) | C10—C11 | 1.386 (5) |
C1—C12 | 1.505 (5) | C10—H10 | 0.9300 |
C1—C2 | 1.543 (5) | C11—H11 | 0.9300 |
C1—H1 | 0.9800 | C12—C13 | 1.382 (5) |
C2—C3 | 1.508 (5) | C12—C17 | 1.382 (5) |
C2—C19 | 1.519 (5) | C13—C14 | 1.377 (5) |
C2—H2 | 0.9800 | C13—H13 | 0.9300 |
C3—O1 | 1.208 (4) | C14—C15 | 1.373 (5) |
C3—C4 | 1.515 (5) | C14—H14 | 0.9300 |
C4—C18 | 1.516 (5) | C15—C16 | 1.366 (5) |
C4—C5 | 1.533 (5) | C16—C17 | 1.384 (5) |
C4—H4 | 0.9800 | C16—H16 | 0.9300 |
C5—O2 | 1.425 (4) | C17—H17 | 0.9300 |
C5—C6 | 1.503 (5) | C18—H18A | 0.9600 |
C5—H5 | 0.9800 | C18—H18B | 0.9600 |
C6—C7 | 1.378 (5) | C18—H18C | 0.9600 |
C6—C11 | 1.379 (5) | C19—H19A | 0.9600 |
C7—C8 | 1.375 (5) | C19—H19B | 0.9600 |
C7—H7 | 0.9300 | C19—H19C | 0.9600 |
C8—C9 | 1.368 (6) | ||
O2—C1—C12 | 107.7 (3) | C8—C9—Br1 | 118.9 (3) |
O2—C1—C2 | 109.7 (3) | C9—C10—C11 | 119.1 (4) |
C12—C1—C2 | 112.0 (3) | C9—C10—H10 | 120.5 |
O2—C1—H1 | 109.2 | C11—C10—H10 | 120.5 |
C12—C1—H1 | 109.2 | C6—C11—C10 | 120.8 (3) |
C2—C1—H1 | 109.2 | C6—C11—H11 | 119.6 |
C3—C2—C19 | 112.6 (3) | C10—C11—H11 | 119.6 |
C3—C2—C1 | 107.8 (3) | C13—C12—C17 | 118.5 (3) |
C19—C2—C1 | 113.7 (3) | C13—C12—C1 | 121.1 (3) |
C3—C2—H2 | 107.5 | C17—C12—C1 | 120.4 (3) |
C19—C2—H2 | 107.5 | C14—C13—C12 | 120.9 (3) |
C1—C2—H2 | 107.5 | C14—C13—H13 | 119.5 |
O1—C3—C2 | 122.4 (3) | C12—C13—H13 | 119.5 |
O1—C3—C4 | 122.4 (3) | C15—C14—C13 | 119.2 (3) |
C2—C3—C4 | 115.2 (3) | C15—C14—H14 | 120.4 |
C3—C4—C18 | 112.6 (3) | C13—C14—H14 | 120.4 |
C3—C4—C5 | 110.1 (3) | C16—C15—C14 | 121.5 (3) |
C18—C4—C5 | 112.4 (3) | C16—C15—Br2 | 119.1 (3) |
C3—C4—H4 | 107.1 | C14—C15—Br2 | 119.4 (3) |
C18—C4—H4 | 107.1 | C15—C16—C17 | 118.7 (3) |
C5—C4—H4 | 107.1 | C15—C16—H16 | 120.6 |
O2—C5—C6 | 106.8 (3) | C17—C16—H16 | 120.6 |
O2—C5—C4 | 111.8 (3) | C12—C17—C16 | 121.2 (3) |
C6—C5—C4 | 112.0 (3) | C12—C17—H17 | 119.4 |
O2—C5—H5 | 108.7 | C16—C17—H17 | 119.4 |
C6—C5—H5 | 108.7 | C4—C18—H18A | 109.5 |
C4—C5—H5 | 108.7 | C4—C18—H18B | 109.5 |
C7—C6—C11 | 118.3 (3) | H18A—C18—H18B | 109.5 |
C7—C6—C5 | 121.5 (3) | C4—C18—H18C | 109.5 |
C11—C6—C5 | 120.2 (3) | H18A—C18—H18C | 109.5 |
C8—C7—C6 | 121.5 (4) | H18B—C18—H18C | 109.5 |
C8—C7—H7 | 119.3 | C2—C19—H19A | 109.5 |
C6—C7—H7 | 119.3 | C2—C19—H19B | 109.5 |
C9—C8—C7 | 119.0 (4) | H19A—C19—H19B | 109.5 |
C9—C8—H8 | 120.5 | C2—C19—H19C | 109.5 |
C7—C8—H8 | 120.5 | H19A—C19—H19C | 109.5 |
C10—C9—C8 | 121.3 (3) | H19B—C19—H19C | 109.5 |
C10—C9—Br1 | 119.8 (3) | C1—O2—C5 | 113.6 (2) |
O2—C1—C2—C3 | −57.3 (3) | C7—C8—C9—Br1 | −179.2 (3) |
C12—C1—C2—C3 | −176.8 (3) | C8—C9—C10—C11 | −1.5 (6) |
O2—C1—C2—C19 | 177.1 (3) | Br1—C9—C10—C11 | 178.7 (3) |
C12—C1—C2—C19 | 57.7 (4) | C7—C6—C11—C10 | 1.1 (5) |
C19—C2—C3—O1 | −0.9 (5) | C5—C6—C11—C10 | 179.8 (3) |
C1—C2—C3—O1 | −127.2 (4) | C9—C10—C11—C6 | 0.5 (6) |
C19—C2—C3—C4 | 177.5 (3) | O2—C1—C12—C13 | −38.4 (4) |
C1—C2—C3—C4 | 51.3 (4) | C2—C1—C12—C13 | 82.2 (4) |
O1—C3—C4—C18 | 5.0 (5) | O2—C1—C12—C17 | 144.6 (3) |
C2—C3—C4—C18 | −173.4 (3) | C2—C1—C12—C17 | −94.8 (4) |
O1—C3—C4—C5 | 131.3 (4) | C17—C12—C13—C14 | 1.9 (5) |
C2—C3—C4—C5 | −47.1 (4) | C1—C12—C13—C14 | −175.1 (3) |
C3—C4—C5—O2 | 48.3 (4) | C12—C13—C14—C15 | 0.4 (6) |
C18—C4—C5—O2 | 174.7 (3) | C13—C14—C15—C16 | −1.9 (6) |
C3—C4—C5—C6 | 168.1 (3) | C13—C14—C15—Br2 | 174.9 (3) |
C18—C4—C5—C6 | −65.5 (4) | C14—C15—C16—C17 | 1.0 (6) |
O2—C5—C6—C7 | −134.4 (3) | Br2—C15—C16—C17 | −175.8 (3) |
C4—C5—C6—C7 | 103.0 (4) | C13—C12—C17—C16 | −2.8 (5) |
O2—C5—C6—C11 | 47.0 (4) | C1—C12—C17—C16 | 174.2 (3) |
C4—C5—C6—C11 | −75.7 (4) | C15—C16—C17—C12 | 1.4 (6) |
C11—C6—C7—C8 | −1.7 (6) | C12—C1—O2—C5 | −173.8 (3) |
C5—C6—C7—C8 | 179.7 (3) | C2—C1—O2—C5 | 64.2 (3) |
C6—C7—C8—C9 | 0.7 (6) | C6—C5—O2—C1 | 177.7 (3) |
C7—C8—C9—C10 | 1.0 (6) | C4—C5—O2—C1 | −59.5 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···Cgi | 0.98 | 2.77 | 3.687 | 156 |
C14—H14···O1ii | 0.93 | 2.68 | 3.403 (5) | 136 |
Symmetry codes: (i) −x+2, y+1/2, −z+3/2; (ii) x+1/2, y, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C19H18Br2O2 |
Mr | 438.15 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 297 |
a, b, c (Å) | 15.146 (3), 9.1460 (18), 26.180 (5) |
V (Å3) | 3626.6 (12) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 4.48 |
Crystal size (mm) | 0.22 × 0.20 × 0.19 |
Data collection | |
Diffractometer | Bruker Kappa-APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.439, 0.483 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 38553, 3450, 2171 |
Rint | 0.047 |
(sin θ/λ)max (Å−1) | 0.616 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.094, 1.05 |
No. of reflections | 3450 |
No. of parameters | 210 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.62, −0.41 |
Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···Cgi | 0.98 | 2.766 | 3.687 | 156 |
C14—H14···O1ii | 0.93 | 2.68 | 3.403 (5) | 136 |
Symmetry codes: (i) −x+2, y+1/2, −z+3/2; (ii) x+1/2, y, −z+3/2. |
Pyran-4-one derivatives are very important, naturally available and biologically active six-membered heterocyclic compounds (Noller, 1966). Japp and Maitland were the first to report the synthesis of several substituted tetrahydropyran derivatives (Japp & Maitland, 1904). While reviewing the literature, depending upon the number and nature of the substituents and the level of unsaturation, different conformations are reported for the six-membered heterocyclic ring, namely, sofa (Ray et al., 1998), planar (Kumar et al., 1999), chair (Belakhov et al., 2002; Krishnamoorthy et al., 2003; Jose Kavitha et al., 2003) or twist boat (Usman et al., 2002). Moreover, the synthesized compound contains two pairs of chiral carbons with identical groups on each. According to Eliel, there can be four racemic and two meso forms (Eliel, 1962).
In the title compound C19H18Br2O2, as shown in Fig. 1, the tetrahydropyran ring adopts a chair conformation. Both the methyl groups and p-Br phenyl rings occupy equatorial positions. Similar kinds of compounds with p-Cl or p-CH3 substituents reported earlier exist in the chair conformation with equatorial orientations of all the phenyl and methyl groups. The absolute configuration of the chiral atoms C1, C2, C4 and C5 are S, R, S and R, respectively.
The crystal structure is stabilized by intermolecular C—H···O, C—H···π and Br···Br interactions. These contacts facilitate the formation of a zigzag network extendend over the ac plane. In the crystal structure the adjacent layers are linked through C—H···π interactions, viz. C4—H4···Cgi with H4···Cgi = 2.766 Å, C4···Cgi = 3.687 Å and C4—H4···Cgi = 156°, where Cgi denotes the centroid of the C12–C17 aryl ring of the molecule (symmetry code: i = 2 - x, 1/2 + y, 3/2 - z).
The molecules are also held together by C—H···O interactions between C14 and O1ii of 3.403 (5) Å, C14—H14···O1ii = 136°, symmetry code: ii = 1/2 + x, y, 3/2 - z. A short contact is also seen between Br1···Br2iii (3.4756 (9) Å, symmetry code: iii = 5/2 - x,-y,-1/2 + z).