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In the title compound, (2S,3R,3aR)-2-(1,3-benzodioxol-5-yl)-3,3a-di­hydro-3a-methoxy-3-methyl-5-(2-propenyl)-6(2H)-ben­zo­furan­one, C20H20O5, the furan ring has a half-chair conformation with its O atom on the twist axis. The semi­quinone ring is slightly non-planar, with a maximum deviation of 0.065 (3) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801017779/om6065sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801017779/om6065Isup2.hkl
Contains datablock I

CCDC reference: 176035

Key indicators

  • Single-crystal X-ray study
  • T = 100 K
  • Mean [sigma](C-C) = 0.006 Å
  • R factor = 0.061
  • wR factor = 0.166
  • Data-to-parameter ratio = 11.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes

REFLT_03 From the CIF: _diffrn_reflns_theta_max 30.00 From the CIF: _reflns_number_total 2619 From the CIF: _diffrn_reflns_limit_ max hkl 21. 9. 21. From the CIF: _diffrn_reflns_limit_ min hkl -24. 0. -19. TEST1: Expected hkl limits for theta max Calculated maximum hkl 25. 9. 23. Calculated minimum hkl -25. -9. -23. ALERT: Expected hkl max differ from CIF values REFLT_03 From the CIF: _diffrn_reflns_theta_max 30.00 From the CIF: _reflns_number_total 2619 Count of symmetry unique reflns 2706 Completeness (_total/calc) 96.78% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 Are heavy atom types Z>Si present no Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF.

Comment top

The title neolignan, (I), has previously been reported from Magnolia denudata (Iida et al., 1982; Kuroyanagi et al., 2000), Magnolia liliflora (Iida & Ito, 1983) and Magnolia soulangiana (Abdallah, 1993).

The furan ring has the half-chair conformation with its O atom on the twist axis, as shown by the torsion angles in Table 1. The semiquinone ring is only slightly non-planar, with its six C atoms exhibiting an r.m.s. deviation of 0.039 Å from coplanarity, with a maximum deviation of 0.065 (3) Å. The propenyl group is twisted out of the semiquinone-ring plane primarily by rotation about the C7'—C8' bond, as indicated by the C1'—C7'—C8'—C9' torsion angle of -125.4 (4)°.

The most closely related neolignan for which the crystal structure has been previously reported is mirandin-A (Tomita, et al., 1977), which differs from the title compound, (I), in having the opposite configuration at C5' and by having a 3,4,5-trimethoxyphenyl substituent rather than the 3,4-methylenedioxyphenyl group of denudatin A. In mirandin-A, the furan ring also has a twist conformation, but with C7 on the twist axis. Its propenyl group also has a different conformation, with a C6'—C1'—C7'—C8' torsion angle of -92.7° and a C1'—C7'—C8'—C9' torsion angle of 2.0°.

Experimental top

Leaves of Magnolia soulangiana, collected in Vancouver, BC, Canada, were air dried, ground and extracted with CH2Cl2 at room temperature for 24 h. The crude extract was separated by standard vacuum liquid chromatography procedures (Cantrell et al., 1996), using silica gel and n-hexane/ethyl acetate mixtures of increasing polarity. Fractions 63–66 (of 66) yielded crystals of denudatin A.

Refinement top

The absolute configuration could not be determined. H atoms were placed in calculated positions with C—H bond distances in the range 0.95–1.00 Å and thereafter treated as riding. A torsional parameter was refined for each methyl group. Uiso = 1.2Ueq of the attached atom (1.5 for methyl groups).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: maXus (Mackay et al., 1999); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The atom-numbering scheme for (I) with ellipsoids at the 40% probability level.
(2S,3R,3aR)-2-(1,3-benzodioxol-5-yl)-3,3a-dihydro-3a-methoxy-3- methyl-5-(2-propenyl)-6(2H)-benzofuranone top
Crystal data top
C20H20O5F(000) = 720
Mr = 340.36Dx = 1.315 Mg m3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
a = 17.8678 (17) ÅCell parameters from 25 reflections
b = 6.7905 (18) Åθ = 10.2–23.4°
c = 16.382 (2) ŵ = 0.09 mm1
β = 120.114 (10)°T = 100 K
V = 1719.4 (5) Å3Needle, colorless
Z = 40.45 × 0.20 × 0.15 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.056
Radiation source: fine-focus sealed tubeθmax = 30.0°, θmin = 1.4°
Graphite monochromatorh = 2421
θ/2θ scansk = 09
3590 measured reflectionsl = 1921
2619 independent reflections3 standard reflections every 120 min
1813 reflections with I > 2σ(I) intensity decay: <1%
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)] = 0.061Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.166H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0922P)2 + 0.03P]
where P = (Fo2 + 2Fc2)/3
2619 reflections(Δ/σ)max < 0.001
228 parametersΔρmax = 0.42 e Å3
1 restraintΔρmin = 0.23 e Å3
Crystal data top
C20H20O5V = 1719.4 (5) Å3
Mr = 340.36Z = 4
Monoclinic, C2Mo Kα radiation
a = 17.8678 (17) ŵ = 0.09 mm1
b = 6.7905 (18) ÅT = 100 K
c = 16.382 (2) Å0.45 × 0.20 × 0.15 mm
β = 120.114 (10)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.056
3590 measured reflections3 standard reflections every 120 min
2619 independent reflections intensity decay: <1%
1813 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0611 restraint
wR(F2) = 0.166H-atom parameters constrained
S = 1.04Δρmax = 0.42 e Å3
2619 reflectionsΔρmin = 0.23 e Å3
228 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.67641 (18)0.0531 (5)0.6518 (2)0.0387 (7)
O20.80453 (17)0.2200 (4)0.74401 (18)0.0337 (6)
O30.28018 (19)0.1076 (5)0.0946 (2)0.0406 (7)
O40.55930 (16)0.3352 (4)0.31577 (17)0.0310 (6)
C10.6435 (2)0.4419 (6)0.4791 (3)0.0249 (7)
C20.6220 (2)0.2735 (5)0.5134 (3)0.0271 (8)
H20.56930.20460.47610.032*
C30.6807 (2)0.2143 (6)0.6026 (3)0.0279 (8)
C40.7574 (2)0.3153 (6)0.6584 (2)0.0277 (8)
C50.7785 (2)0.4829 (6)0.6281 (3)0.0313 (8)
H50.83020.55390.66730.038*
C60.7196 (2)0.5441 (6)0.5359 (3)0.0302 (8)
H60.73220.65850.51160.036*
C70.5849 (2)0.5086 (5)0.3790 (2)0.0256 (8)
H70.61720.60300.36100.031*
C80.4983 (2)0.6023 (5)0.3569 (3)0.0268 (8)
H80.47320.52660.38990.032*
C90.5092 (2)0.8178 (6)0.3876 (3)0.0317 (9)
H9A0.54760.82620.45610.048*
H9B0.45260.87360.37060.048*
H9C0.53440.89190.35590.048*
C100.7626 (3)0.0321 (6)0.7303 (3)0.0359 (9)
H10A0.79430.07050.71690.043*
H10B0.76090.00630.78770.043*
C1'0.2958 (2)0.4395 (6)0.1448 (3)0.0285 (8)
C2'0.3308 (3)0.2401 (6)0.1414 (3)0.0306 (8)
C3'0.4236 (3)0.2069 (6)0.1969 (3)0.0318 (8)
H3'0.44750.08300.19530.038*
C4'0.4741 (2)0.3518 (6)0.2497 (3)0.0273 (8)
O50.47960 (16)0.6938 (4)0.20825 (18)0.0320 (6)
C5'0.4452 (2)0.5614 (5)0.2505 (3)0.0261 (8)
C6'0.3485 (2)0.5819 (6)0.1995 (2)0.0279 (8)
H6'0.32400.70060.20630.033*
C7'0.1989 (2)0.4613 (6)0.0821 (3)0.0335 (9)
H7'10.18300.42280.01710.040*
H7'20.17000.36840.10410.040*
C8'0.1649 (2)0.6641 (7)0.0795 (3)0.0421 (11)
H8'0.18930.77070.06320.050*
C9'0.1032 (3)0.7030 (11)0.0983 (4)0.073 (2)
H9'10.07750.59940.11480.088*
H9'20.08420.83480.09550.088*
C10'0.4577 (3)0.6498 (7)0.1140 (3)0.0400 (10)
H10C0.48170.52100.11220.060*
H10D0.48190.75110.09110.060*
H10E0.39470.64690.07360.060*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0362 (14)0.0289 (15)0.0473 (16)0.0063 (12)0.0182 (12)0.0093 (13)
O20.0352 (13)0.0239 (14)0.0369 (14)0.0001 (12)0.0142 (11)0.0026 (12)
O30.0524 (17)0.0230 (15)0.0442 (16)0.0073 (13)0.0226 (14)0.0067 (13)
O40.0297 (12)0.0192 (13)0.0378 (13)0.0088 (11)0.0122 (10)0.0019 (12)
C10.0233 (15)0.0163 (16)0.0358 (18)0.0035 (13)0.0154 (14)0.0007 (15)
C20.0251 (16)0.0171 (17)0.0389 (19)0.0036 (14)0.0160 (14)0.0009 (14)
C30.0333 (18)0.0134 (15)0.0418 (19)0.0001 (15)0.0225 (15)0.0009 (15)
C40.0278 (17)0.0249 (19)0.0315 (17)0.0006 (16)0.0156 (14)0.0039 (16)
C50.0278 (17)0.0200 (18)0.041 (2)0.0059 (14)0.0136 (15)0.0061 (16)
C60.0291 (17)0.0177 (17)0.043 (2)0.0010 (14)0.0172 (15)0.0021 (16)
C70.0248 (15)0.0156 (16)0.0337 (18)0.0022 (13)0.0126 (14)0.0006 (14)
C80.0248 (16)0.0148 (17)0.0376 (19)0.0018 (14)0.0132 (14)0.0014 (15)
C90.0282 (17)0.0156 (17)0.041 (2)0.0023 (15)0.0100 (15)0.0052 (16)
C100.039 (2)0.025 (2)0.045 (2)0.0046 (17)0.0211 (17)0.0072 (17)
C1'0.0285 (17)0.0226 (18)0.0314 (18)0.0022 (15)0.0128 (14)0.0019 (16)
C2'0.042 (2)0.0199 (18)0.0294 (18)0.0024 (16)0.0172 (15)0.0027 (15)
C3'0.042 (2)0.0174 (17)0.0347 (19)0.0046 (16)0.0180 (16)0.0016 (15)
C4'0.0331 (18)0.0164 (17)0.0353 (18)0.0059 (14)0.0193 (15)0.0035 (15)
O50.0311 (13)0.0211 (14)0.0399 (14)0.0010 (11)0.0149 (11)0.0040 (12)
C5'0.0260 (15)0.0143 (16)0.0341 (18)0.0001 (13)0.0122 (14)0.0020 (14)
C6'0.0259 (16)0.0208 (18)0.0317 (17)0.0025 (15)0.0105 (14)0.0021 (15)
C7'0.0320 (19)0.029 (2)0.0322 (19)0.0078 (16)0.0105 (15)0.0022 (17)
C8'0.0254 (18)0.038 (3)0.043 (2)0.0015 (17)0.0030 (16)0.0118 (19)
C9'0.035 (2)0.083 (5)0.079 (4)0.004 (3)0.012 (2)0.038 (4)
C10'0.040 (2)0.038 (2)0.042 (2)0.0111 (19)0.0208 (17)0.0122 (19)
Geometric parameters (Å, º) top
O1—C31.384 (5)C9—H9C0.9800
O1—C101.435 (5)C10—H10A0.9900
O2—C41.382 (4)C10—H10B0.9900
O2—C101.439 (5)C1'—C6'1.333 (5)
O3—C2'1.233 (5)C1'—C2'1.505 (5)
O4—C4'1.359 (4)C1'—C7'1.512 (5)
O4—C71.481 (4)C2'—C3'1.454 (5)
C1—C61.389 (5)C3'—C4'1.322 (5)
C1—C21.409 (5)C3'—H3'0.9500
C1—C71.506 (5)C4'—C5'1.516 (5)
C2—C31.363 (5)O5—C10'1.422 (5)
C2—H20.9500O5—C5'1.447 (5)
C3—C41.389 (5)C5'—C6'1.502 (5)
C4—C51.368 (6)C6'—H6'0.9500
C5—C61.402 (5)C7'—C8'1.497 (6)
C5—H50.9500C7'—H7'10.9900
C6—H60.9500C7'—H7'20.9900
C7—C81.539 (5)C8'—C9'1.312 (7)
C7—H71.0000C8'—H8'0.9500
C8—C91.529 (5)C9'—H9'10.9500
C8—C5'1.534 (5)C9'—H9'20.9500
C8—H81.0000C10'—H10C0.9800
C9—H9A0.9800C10'—H10D0.9800
C9—H9B0.9800C10'—H10E0.9800
C3—O1—C10104.6 (3)O2—C10—H10B110.3
C4—O2—C10104.6 (3)H10A—C10—H10B108.6
C4'—O4—C7108.7 (3)C6'—C1'—C2'120.7 (3)
C6—C1—C2120.6 (3)C6'—C1'—C7'124.5 (4)
C6—C1—C7119.4 (3)C2'—C1'—C7'114.7 (3)
C2—C1—C7119.9 (3)O3—C2'—C3'121.8 (4)
C3—C2—C1116.7 (3)O3—C2'—C1'119.4 (3)
C3—C2—H2121.6C3'—C2'—C1'118.8 (3)
C1—C2—H2121.6C4'—C3'—C2'118.9 (4)
C2—C3—O1128.3 (3)C4'—C3'—H3'120.5
C2—C3—C4122.3 (4)C2'—C3'—H3'120.5
O1—C3—C4109.4 (3)C3'—C4'—O4125.7 (4)
C5—C4—O2128.3 (3)C3'—C4'—C5'125.5 (3)
C5—C4—C3122.2 (3)O4—C4'—C5'108.7 (3)
O2—C4—C3109.5 (3)C10'—O5—C5'116.0 (3)
C4—C5—C6116.3 (3)O5—C5'—C6'108.8 (3)
C4—C5—H5121.8O5—C5'—C4'110.5 (3)
C6—C5—H5121.8C6'—C5'—C4'112.6 (3)
C1—C6—C5121.8 (4)O5—C5'—C8105.2 (3)
C1—C6—H6119.1C6'—C5'—C8119.9 (3)
C5—C6—H6119.1C4'—C5'—C899.2 (3)
O4—C7—C1108.9 (3)C1'—C6'—C5'122.3 (3)
O4—C7—C8104.0 (3)C1'—C6'—H6'118.8
C1—C7—C8116.6 (3)C5'—C6'—H6'118.8
O4—C7—H7109.0C8'—C7'—C1'114.8 (3)
C1—C7—H7109.0C8'—C7'—H7'1108.6
C8—C7—H7109.0C1'—C7'—H7'1108.6
C9—C8—C5'116.9 (3)C8'—C7'—H7'2108.6
C9—C8—C7111.8 (3)C1'—C7'—H7'2108.6
C5'—C8—C799.7 (3)H7'1—C7'—H7'2107.5
C9—C8—H8109.3C9'—C8'—C7'123.7 (5)
C5'—C8—H8109.3C9'—C8'—H8'118.1
C7—C8—H8109.3C7'—C8'—H8'118.1
C8—C9—H9A109.5C8'—C9'—H9'1120.0
C8—C9—H9B109.5C8'—C9'—H9'2120.0
H9A—C9—H9B109.5H9'1—C9'—H9'2120.0
C8—C9—H9C109.5O5—C10'—H10C109.5
H9A—C9—H9C109.5O5—C10'—H10D109.5
H9B—C9—H9C109.5H10C—C10'—H10D109.5
O1—C10—O2107.0 (3)O5—C10'—H10E109.5
O1—C10—H10A110.3H10C—C10'—H10E109.5
O2—C10—H10A110.3H10D—C10'—H10E109.5
O1—C10—H10B110.3
C6—C1—C2—C32.1 (5)C6'—C1'—C2'—C3'1.6 (6)
C7—C1—C2—C3175.9 (4)C7'—C1'—C2'—C3'178.0 (3)
C1—C2—C3—O1178.5 (3)O3—C2'—C3'—C4'176.4 (4)
C1—C2—C3—C41.0 (6)C1'—C2'—C3'—C4'1.0 (6)
C10—O1—C3—C2165.7 (4)C2'—C3'—C4'—O4169.4 (4)
C10—O1—C3—C413.8 (4)C2'—C3'—C4'—C5'6.8 (6)
C10—O2—C4—C5167.4 (4)C7—O4—C4'—C3'162.2 (4)
C10—O2—C4—C312.7 (4)C7—O4—C4'—C5'14.5 (4)
C2—C3—C4—C51.2 (6)C10'—O5—C5'—C6'66.5 (4)
O1—C3—C4—C5179.2 (4)C10'—O5—C5'—C4'57.6 (4)
C2—C3—C4—O2178.9 (4)C10'—O5—C5'—C8163.8 (3)
O1—C3—C4—O20.7 (4)C3'—C4'—C5'—O5110.0 (4)
O2—C4—C5—C6177.9 (4)O4—C4'—C5'—O573.3 (4)
C3—C4—C5—C62.2 (6)C3'—C4'—C5'—C6'11.9 (6)
C2—C1—C6—C51.1 (6)O4—C4'—C5'—C6'164.8 (3)
C7—C1—C6—C5176.9 (4)C3'—C4'—C5'—C8139.9 (4)
C4—C5—C6—C11.1 (6)O4—C4'—C5'—C836.9 (4)
C4'—O4—C7—C1139.0 (3)C9—C8—C5'—O548.5 (4)
C4'—O4—C7—C814.1 (4)C7—C8—C5'—O572.0 (3)
C6—C1—C7—O4133.0 (4)C9—C8—C5'—C6'74.2 (5)
C2—C1—C7—O445.0 (4)C7—C8—C5'—C6'165.2 (3)
C6—C1—C7—C8109.8 (4)C9—C8—C5'—C4'162.9 (3)
C2—C1—C7—C872.2 (4)C7—C8—C5'—C4'42.3 (3)
O4—C7—C8—C9159.9 (3)C2'—C1'—C6'—C5'7.8 (6)
C1—C7—C8—C980.2 (4)C7'—C1'—C6'—C5'171.8 (4)
O4—C7—C8—C5'35.7 (3)O5—C5'—C6'—C1'110.8 (4)
C1—C7—C8—C5'155.6 (3)C4'—C5'—C6'—C1'12.1 (5)
C3—O1—C10—O221.5 (4)C8—C5'—C6'—C1'128.2 (4)
C4—O2—C10—O121.1 (4)C6'—C1'—C7'—C8'4.3 (6)
C6'—C1'—C2'—O3175.8 (4)C2'—C1'—C7'—C8'175.3 (4)
C7'—C1'—C2'—O34.5 (5)C1'—C7'—C8'—C9'125.4 (4)

Experimental details

Crystal data
Chemical formulaC20H20O5
Mr340.36
Crystal system, space groupMonoclinic, C2
Temperature (K)100
a, b, c (Å)17.8678 (17), 6.7905 (18), 16.382 (2)
β (°) 120.114 (10)
V3)1719.4 (5)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.45 × 0.20 × 0.15
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3590, 2619, 1813
Rint0.056
(sin θ/λ)max1)0.703
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.061, 0.166, 1.04
No. of reflections2619
No. of parameters228
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.42, 0.23

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, maXus (Mackay et al., 1999), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), SHELXL97.

Selected geometric parameters (Å, º) top
O3—C2'1.233 (5)C3'—C4'1.322 (5)
C1'—C6'1.333 (5)C8'—C9'1.312 (7)
C4'—O4—C7108.7 (3)C9'—C8'—C7'123.7 (5)
C4'—O4—C7—C814.1 (4)O4—C4'—C5'—C836.9 (4)
C2—C1—C7—O445.0 (4)C7—C8—C5'—C4'42.3 (3)
O4—C7—C8—C5'35.7 (3)C6'—C1'—C7'—C8'4.3 (6)
C7—O4—C4'—C5'14.5 (4)C1'—C7'—C8'—C9'125.4 (4)
C10'—O5—C5'—C4'57.6 (4)
 

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