supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

Acta Cryst. (2009). E65, o586    [ doi:10.1107/S1600536809004231 ]

2-(4-Methoxyphenoxy)-6-methyl-3-oxo-3,6-dihydro-2H-pyran-4-yl benzoate

S. Yan, X. Liang, J. Zhang and D. Wang

Abstract top

The title compound, C20H18O6, has been synthesized from 4-methoxyphenyl 3-O-benzoyloxy-[alpha]-L-rhamnopyranoside by oxidation on treatment with pyridinium dichromate in the presence of acetic anhydride. In the molecule, the pyran ring adopts an envelope conformation with the O atom at the flap position. Weak intermolecular C-H...O hydrogen bonding is present in the crystal structure.

Comment top

The enolone structural unit is often present in nature products, such as brevifolic acid, a constituent of the ellagitannins (Schmidt et al., 1954), meliacinslike cedrelone and anthothecol (Hodges et al., 1963; Bevan et al., 1963) or triterpenoids of the elaterin type, which are widely distributed in cucurbitaceous and cruciferous plants (Ripperger & Seifert, 1975). In a continuation of our search for alcohol oxidation (Yan et al., 2008), herein we present the crystal structure of the title compound, which was produced by oxidation with PDC and acetic anhydride.

In the molecule of the title compound (Fig. 1), the pyran ring conformation can be described as an envelope, with C1/C2/C3/C4/C5 lying almost on the same plane and O1 deviating from this mean plane. The terminal benzene rings of the molecule are nearly perpendicular to each other with a dihedral angle of 83.6 (1)°. The weak intermolecular C—H···O hydrogen bonding presents in the crystal structure (Table 1).

Related literature top

For general background to enolone derivatives, see: Schmidt et al. (1954); Hodges et al. (1963); Bevan et al. (1963); Ripperger et al. (1975); Yan et al. (2008).

Experimental top

A mixture of 4-methoxyphenyl 3-O-benzoyloxy-a-L-rhamnopyranoside (3.74 g, 10 mmol), pyridinium dichromate (4.60 g, 12 mmol), and acetic anhydride (5.68 ml, 60 mmol) in CH2Cl2 (40 ml) was stirred at reflux for 8 h, at the end of which time TLC (4:1 petroleumether–EtOAc) indicated that the reaction was complete. After direct concentration of the reaction mixture, the dark brown residue was diluted with EtOAc (60 ml) and the solution was passed through a short (5–10 cm) silica-gel column. The column was eluted with EtOAc and the eluents were concentrated and coevaporated with toluene. The residue was subjected to silica-gel column chromatography again (4:1 petroleum ether–EtOAc) to give the title compound (2.48 g, 70%). Single crystals suitable for X-ray measurements were obtained by recrystallization from 8:1 petroleumether–EtOAc at room temperature.

Refinement top

H atoms were positioned geometrically, with C—H = 0.95 Å, 0.98 Å and 1.00 Å for aromatic, methyl and methine H, respectively, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x= 1.5 for methyl H and x = 1.2 for other H. The absolute structure was not determined for this structure, Friedel pairs were merged.

Computing details top

Data collection: RAPID-AUTO (Rigaku, 2001); cell refinement: RAPID-AUTO (Rigaku, 2001); data reduction: RAPID-AUTO (Rigaku, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atomic labelling and displacement ellipsoids drawn at the 50% probability level.
2-(4-Methoxyphenoxy)-6-methyl-3-oxo-3,6-dihydro-2H-pyran-4-yl benzoate top
Crystal data top
C20H18O6F(000) = 744
Mr = 354.34Dx = 1.358 Mg m−3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 789 reflections
a = 8.5906 (17) Åθ = 2.2–27.5°
b = 11.594 (2) ŵ = 0.10 mm−1
c = 17.404 (4) ÅT = 173 K
V = 1733.4 (6) Å3Block, colorless
Z = 40.80 × 0.72 × 0.40 mm
Data collection top
Rigaku R-Axis Rapid IP are-detector
diffractometer		2262 independent reflections
Radiation source: rotating anode1752 reflections with I > 2σ(I)
graphiteRint = 0.015
ω scanθmax = 27.4°, θmin = 2.1°
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)		h = −11→11
Tmin = 0.924, Tmax = 0.961k = −14→15
3953 measured reflectionsl = −22→22
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.034H-atom parameters constrained
wR(F2) = 0.055 w = 1/[σ2(Fo2)]
S = 0.87(Δ/σ)max = 0.001
2262 reflectionsΔρmax = 0.17 e Å−3
236 parametersΔρmin = −0.24 e Å−3
0 restraintsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0215 (13)
Crystal data top
C20H18O6V = 1733.4 (6) Å3
Mr = 354.34Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 8.5906 (17) ŵ = 0.10 mm−1
b = 11.594 (2) ÅT = 173 K
c = 17.404 (4) Å0.80 × 0.72 × 0.40 mm
Data collection top
Rigaku R-Axis Rapid IP are-detector
diffractometer		2262 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)		1752 reflections with I > 2σ(I)
Tmin = 0.924, Tmax = 0.961Rint = 0.015
3953 measured reflectionsθmax = 27.4°
Refinement top
R[F2 > 2σ(F2)] = 0.034H-atom parameters constrained
wR(F2) = 0.055Δρmax = 0.17 e Å−3
S = 0.87Δρmin = −0.24 e Å−3
2262 reflectionsAbsolute structure: ?
236 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O11.17184 (15)0.59200 (11)0.94630 (8)0.0262 (4)
O20.93224 (17)0.89681 (11)0.91264 (8)0.0298 (4)
O31.04268 (19)0.94639 (12)1.02536 (9)0.0370 (4)
O41.21198 (18)0.84659 (12)0.84053 (9)0.0372 (4)
O51.13746 (15)0.59345 (11)0.81269 (7)0.0230 (3)
O61.36640 (18)0.16881 (11)0.72242 (9)0.0371 (4)
C11.0087 (2)0.58644 (17)0.96426 (13)0.0278 (5)
H1A0.95750.53020.92880.033*
C20.9327 (3)0.70107 (17)0.95530 (12)0.0290 (5)
H2A0.83180.71230.97630.035*
C31.0009 (3)0.78794 (17)0.91900 (12)0.0257 (5)
C41.1459 (2)0.77091 (16)0.87611 (12)0.0250 (5)
C51.2071 (2)0.64760 (16)0.87719 (11)0.0236 (5)
H5A1.32260.64880.87010.028*
C60.9976 (3)0.5411 (2)1.04592 (14)0.0425 (6)
H6A1.04860.46571.04910.064*
H6B0.88780.53331.06040.064*
H6C1.04910.59521.08100.064*
C70.9639 (2)0.97192 (17)0.97094 (13)0.0251 (5)
C80.8888 (2)1.08488 (16)0.95760 (12)0.0230 (5)
C90.8571 (3)1.15548 (17)1.02010 (13)0.0304 (5)
H9A0.88521.13161.07050.037*
C100.7844 (3)1.26088 (18)1.00880 (15)0.0379 (6)
H10A0.76211.30921.05150.045*
C110.7445 (3)1.29565 (18)0.93534 (14)0.0384 (6)
H11A0.69461.36790.92770.046*
C120.7767 (3)1.22605 (17)0.87332 (14)0.0340 (6)
H12A0.74981.25070.82300.041*
C130.8478 (2)1.12062 (16)0.88406 (12)0.0278 (5)
H13A0.86871.07240.84120.033*
C141.1981 (2)0.48407 (16)0.79498 (10)0.0203 (5)
C151.3486 (2)0.47295 (16)0.76804 (11)0.0242 (5)
H15A1.41470.53850.76520.029*
C161.4024 (2)0.36583 (16)0.74524 (12)0.0260 (5)
H16A1.50600.35730.72710.031*
C171.3043 (2)0.27089 (16)0.74899 (12)0.0247 (5)
C181.1540 (3)0.28231 (17)0.77601 (12)0.0278 (5)
H18A1.08690.21730.77840.033*
C191.1018 (2)0.39045 (16)0.79972 (11)0.0260 (5)
H19A0.99920.39910.81920.031*
C201.2665 (3)0.07108 (16)0.72123 (15)0.0446 (7)
H20A1.32330.00440.70100.067*
H20B1.17650.08710.68830.067*
H20C1.23070.05440.77350.067*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0262 (8)0.0268 (8)0.0256 (8)0.0052 (7)−0.0006 (6)0.0013 (7)
O20.0395 (9)0.0208 (8)0.0292 (8)0.0097 (7)−0.0036 (7)−0.0066 (7)
O30.0455 (10)0.0285 (9)0.0370 (10)0.0032 (7)−0.0157 (8)−0.0016 (7)
O40.0356 (10)0.0274 (8)0.0486 (10)−0.0030 (8)0.0019 (8)0.0054 (8)
O50.0236 (8)0.0212 (7)0.0244 (7)0.0041 (7)−0.0024 (6)−0.0035 (6)
O60.0275 (9)0.0231 (8)0.0607 (11)0.0022 (7)−0.0003 (9)−0.0118 (8)
C10.0272 (12)0.0244 (12)0.0319 (12)0.0035 (10)0.0030 (10)0.0004 (10)
C20.0276 (12)0.0339 (13)0.0255 (12)0.0059 (10)0.0044 (10)−0.0026 (10)
C30.0294 (13)0.0236 (11)0.0242 (11)0.0062 (10)−0.0048 (10)−0.0063 (10)
C40.0274 (13)0.0233 (11)0.0244 (11)−0.0013 (10)−0.0071 (10)−0.0039 (10)
C50.0199 (11)0.0251 (11)0.0258 (11)0.0026 (9)−0.0010 (10)−0.0013 (10)
C60.0481 (15)0.0426 (14)0.0367 (14)0.0099 (13)0.0097 (12)0.0110 (12)
C70.0249 (12)0.0227 (11)0.0278 (12)−0.0028 (10)0.0029 (10)−0.0022 (10)
C80.0196 (11)0.0199 (11)0.0295 (12)−0.0031 (9)0.0026 (9)−0.0009 (9)
C90.0358 (14)0.0268 (12)0.0287 (12)−0.0022 (11)0.0055 (11)−0.0010 (10)
C100.0484 (16)0.0218 (11)0.0434 (15)0.0026 (12)0.0142 (13)−0.0060 (11)
C110.0384 (15)0.0229 (12)0.0540 (17)0.0059 (11)0.0116 (13)0.0059 (11)
C120.0355 (14)0.0283 (13)0.0382 (14)0.0017 (11)0.0016 (12)0.0096 (11)
C130.0284 (12)0.0262 (12)0.0288 (12)−0.0008 (10)0.0030 (10)−0.0023 (10)
C140.0229 (12)0.0194 (10)0.0185 (10)0.0038 (9)−0.0009 (9)−0.0022 (8)
C150.0235 (12)0.0207 (10)0.0284 (12)−0.0047 (10)0.0006 (10)0.0005 (9)
C160.0170 (11)0.0284 (12)0.0326 (12)0.0022 (9)0.0041 (10)−0.0016 (10)
C170.0243 (13)0.0214 (11)0.0285 (12)0.0056 (9)−0.0048 (10)−0.0028 (9)
C180.0236 (12)0.0232 (11)0.0367 (13)−0.0053 (10)0.0011 (11)−0.0004 (10)
C190.0212 (12)0.0280 (12)0.0287 (12)0.0001 (10)0.0040 (9)−0.0019 (10)
C200.0363 (15)0.0194 (11)0.0782 (19)0.0025 (11)−0.0133 (14)−0.0114 (12)
Geometric parameters (Å, °) top
O1—C51.398 (2)C8—C131.391 (3)
O1—C11.437 (2)C9—C101.386 (3)
O2—C71.365 (2)C9—H9A0.9500
O2—C31.398 (2)C10—C111.384 (3)
O3—C71.201 (2)C10—H10A0.9500
O4—C41.215 (2)C11—C121.376 (3)
O5—C141.405 (2)C11—H11A0.9500
O5—C51.418 (2)C12—C131.379 (3)
O6—C171.378 (2)C12—H12A0.9500
O6—C201.422 (2)C13—H13A0.9500
C1—C21.489 (3)C14—C191.367 (3)
C1—C61.518 (3)C14—C151.381 (3)
C1—H1A1.0000C15—C161.383 (3)
C2—C31.326 (3)C15—H15A0.9500
C2—H2A0.9500C16—C171.387 (3)
C3—C41.465 (3)C16—H16A0.9500
C4—C51.523 (3)C17—C181.381 (3)
C5—H5A1.0000C18—C191.394 (3)
C6—H6A0.9800C18—H18A0.9500
C6—H6B0.9800C19—H19A0.9500
C6—H6C0.9800C20—H20A0.9800
C7—C81.478 (3)C20—H20B0.9800
C8—C91.388 (3)C20—H20C0.9800
C5—O1—C1114.77 (15)C10—C9—H9A120.1
C7—O2—C3115.67 (16)C8—C9—H9A120.1
C14—O5—C5114.64 (14)C11—C10—C9120.0 (2)
C17—O6—C20117.11 (17)C11—C10—H10A120.0
O1—C1—C2111.40 (17)C9—C10—H10A120.0
O1—C1—C6106.29 (18)C12—C11—C10120.3 (2)
C2—C1—C6112.29 (19)C12—C11—H11A119.9
O1—C1—H1A108.9C10—C11—H11A119.9
C2—C1—H1A108.9C11—C12—C13120.2 (2)
C6—C1—H1A108.9C11—C12—H12A119.9
C3—C2—C1122.3 (2)C13—C12—H12A119.9
C3—C2—H2A118.9C12—C13—C8120.1 (2)
C1—C2—H2A118.9C12—C13—H13A120.0
C2—C3—O2122.5 (2)C8—C13—H13A120.0
C2—C3—C4121.08 (19)C19—C14—C15120.83 (18)
O2—C3—C4116.11 (18)C19—C14—O5118.64 (18)
O4—C4—C3124.03 (19)C15—C14—O5120.37 (17)
O4—C4—C5121.5 (2)C14—C15—C16119.60 (18)
C3—C4—C5114.42 (18)C14—C15—H15A120.2
O1—C5—O5112.68 (15)C16—C15—H15A120.2
O1—C5—C4111.63 (17)C15—C16—C17119.73 (19)
O5—C5—C4105.08 (15)C15—C16—H16A120.1
O1—C5—H5A109.1C17—C16—H16A120.1
O5—C5—H5A109.1O6—C17—C18123.95 (19)
C4—C5—H5A109.1O6—C17—C16115.51 (19)
C1—C6—H6A109.5C18—C17—C16120.52 (18)
C1—C6—H6B109.5C17—C18—C19119.18 (19)
H6A—C6—H6B109.5C17—C18—H18A120.4
C1—C6—H6C109.5C19—C18—H18A120.4
H6A—C6—H6C109.5C14—C19—C18120.1 (2)
H6B—C6—H6C109.5C14—C19—H19A119.9
O3—C7—O2122.79 (19)C18—C19—H19A119.9
O3—C7—C8126.03 (19)O6—C20—H20A109.5
O2—C7—C8111.18 (18)O6—C20—H20B109.5
C9—C8—C13119.72 (19)H20A—C20—H20B109.5
C9—C8—C7119.00 (19)O6—C20—H20C109.5
C13—C8—C7121.27 (18)H20A—C20—H20C109.5
C10—C9—C8119.8 (2)H20B—C20—H20C109.5
C5—O1—C1—C2−48.6 (2)O3—C7—C8—C13157.1 (2)
C5—O1—C1—C6−171.17 (16)O2—C7—C8—C13−23.2 (3)
O1—C1—C2—C314.0 (3)C13—C8—C9—C100.2 (3)
C6—C1—C2—C3133.1 (2)C7—C8—C9—C10−179.0 (2)
C1—C2—C3—O2−177.84 (19)C8—C9—C10—C11−0.3 (3)
C1—C2—C3—C48.9 (3)C9—C10—C11—C120.0 (4)
C7—O2—C3—C289.0 (2)C10—C11—C12—C130.6 (4)
C7—O2—C3—C4−97.4 (2)C11—C12—C13—C8−0.7 (3)
C2—C3—C4—O4178.5 (2)C9—C8—C13—C120.3 (3)
O2—C3—C4—O44.8 (3)C7—C8—C13—C12179.49 (19)
C2—C3—C4—C50.3 (3)C5—O5—C14—C19116.7 (2)
O2—C3—C4—C5−173.41 (17)C5—O5—C14—C15−67.9 (2)
C1—O1—C5—O5−59.9 (2)C19—C14—C15—C160.3 (3)
C1—O1—C5—C458.1 (2)O5—C14—C15—C16−174.99 (17)
C14—O5—C5—O1−68.5 (2)C14—C15—C16—C170.6 (3)
C14—O5—C5—C4169.78 (16)C20—O6—C17—C181.8 (3)
O4—C4—C5—O1149.13 (18)C20—O6—C17—C16−176.5 (2)
C3—C4—C5—O1−32.6 (2)C15—C16—C17—O6177.71 (17)
O4—C4—C5—O5−88.4 (2)C15—C16—C17—C18−0.6 (3)
C3—C4—C5—O589.8 (2)O6—C17—C18—C19−178.37 (19)
C3—O2—C7—O3−1.6 (3)C16—C17—C18—C19−0.2 (3)
C3—O2—C7—C8178.67 (17)C15—C14—C19—C18−1.1 (3)
O3—C7—C8—C9−23.8 (3)O5—C14—C19—C18174.26 (17)
O2—C7—C8—C9155.93 (18)C17—C18—C19—C141.0 (3)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C15—H15A···O6i0.952.423.343 (2)163
Symmetry codes: (i) −x+3, y+1/2, −z+3/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C15—H15A···O6i0.952.423.343 (2)163
Symmetry codes: (i) −x+3, y+1/2, −z+3/2.
Acknowledgements top

The authors thank the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry (No. 21168020) and the Doctoral Program Foundation of Institutions of Higher Education of China (No. 20070019072) for support.

references
References top

Bevan, C. W. L., Rees, A. H. & Taylor, D. A. H. (1963). J. Chem. Soc. pp. 983–989.

Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.

Hodges, R., McGeachin, S. G. & Raphael, R. A. H. (1963). J. Chem. Soc. pp. 2515–2526.

Rigaku (2001). RAPID-AUTO. Rigaku Corporation, Tokyo.

Ripperger, H. & Seifert, K. (1975). Tetrahedron, 31, 1561–1563.

Schmidt, O. T. & Bernauer, K. (1954). Justus Liebigs Ann. Chem. 588, 211–230.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Yan, S. Q., Liang, X. M., Diao, P. Y., Yang, Y., Zhang, J. J., Wang, D. Q. & Kong, F. Z. (2008). Carbohydr. Res. 343, 3107–3111.