Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801017482/ob6082sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801017482/ob6082Isup2.hkl |
CCDC reference: 176030
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 58–61 (of 66) yielded crystals of futoenone.
The absolute configuration could not be determined. H atoms were placed in calculated positions with C—H distances in the range 0.93–0.98 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).
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.
C20H20O5 | Dx = 1.369 Mg m−3 |
Mr = 340.36 | Cu Kα radiation, λ = 1.54180 Å |
Trigonal, P31 | Cell parameters from 25 reflections |
a = 7.5210 (6) Å | θ = 23.5–42.6° |
c = 25.2821 (13) Å | µ = 0.81 mm−1 |
V = 1238.50 (15) Å3 | T = 297 K |
Z = 3 | Trigonal prism, colorless |
F(000) = 540 | 0.45 × 0.34 × 0.34 mm |
Enraf-Nonius CAD-4 diffractometer | 1727 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.044 |
Graphite monochromator | θmax = 74.9°, θmin = 5.2° |
θ/2θ scans | h = −9→9 |
Absorption correction: ψ scan (North et al., 1968) | k = −9→9 |
Tmin = 0.614, Tmax = 0.724 | l = 0→31 |
4948 measured reflections | 3 standard reflections every 120 min |
1748 independent reflections | intensity decay: 1.0% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.033 | H-atom parameters constrained |
wR(F2) = 0.085 | w = 1/[σ2(Fo2) + (0.0526P)2 + 0.0948P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max < 0.001 |
1748 reflections | Δρmax = 0.23 e Å−3 |
229 parameters | Δρmin = −0.17 e Å−3 |
1 restraint | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0076 (11) |
C20H20O5 | Z = 3 |
Mr = 340.36 | Cu Kα radiation |
Trigonal, P31 | µ = 0.81 mm−1 |
a = 7.5210 (6) Å | T = 297 K |
c = 25.2821 (13) Å | 0.45 × 0.34 × 0.34 mm |
V = 1238.50 (15) Å3 |
Enraf-Nonius CAD-4 diffractometer | 1727 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.044 |
Tmin = 0.614, Tmax = 0.724 | 3 standard reflections every 120 min |
4948 measured reflections | intensity decay: 1.0% |
1748 independent reflections |
R[F2 > 2σ(F2)] = 0.033 | 1 restraint |
wR(F2) = 0.085 | H-atom parameters constrained |
S = 1.10 | Δρmax = 0.23 e Å−3 |
1748 reflections | Δρmin = −0.17 e Å−3 |
229 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 | ||
O1 | 1.1479 (2) | 0.8471 (3) | 0.50004 (7) | 0.0556 (4) | |
O2 | 1.0624 (3) | 0.7416 (3) | 0.58724 (7) | 0.0585 (5) | |
O3 | 0.0405 (2) | 0.3643 (3) | 0.39544 (6) | 0.0447 (4) | |
O4 | −0.0828 (3) | −0.2487 (3) | 0.31202 (9) | 0.0627 (5) | |
O5 | 0.1715 (3) | −0.0237 (3) | 0.23485 (7) | 0.0586 (5) | |
C1 | 0.5913 (3) | 0.5173 (3) | 0.47896 (7) | 0.0339 (4) | |
C2 | 0.7965 (3) | 0.6495 (3) | 0.46484 (7) | 0.0360 (4) | |
H2 | 0.8337 | 0.6903 | 0.4299 | 0.043* | |
C3 | 0.9402 (3) | 0.7163 (3) | 0.50433 (8) | 0.0371 (4) | |
C4 | 0.8881 (3) | 0.6548 (3) | 0.55644 (8) | 0.0406 (4) | |
C5 | 0.6907 (4) | 0.5273 (4) | 0.57151 (8) | 0.0443 (5) | |
H5 | 0.6562 | 0.4872 | 0.6066 | 0.053* | |
C6 | 0.5414 (3) | 0.4591 (3) | 0.53158 (8) | 0.0405 (4) | |
H6 | 0.4046 | 0.3722 | 0.5405 | 0.049* | |
C7 | 0.4204 (3) | 0.4515 (3) | 0.43851 (7) | 0.0332 (4) | |
H7 | 0.3009 | 0.3293 | 0.4530 | 0.040* | |
C8 | 0.4647 (3) | 0.3891 (3) | 0.38414 (7) | 0.0317 (4) | |
H8 | 0.5975 | 0.5008 | 0.3719 | 0.038* | |
C9 | 0.4833 (4) | 0.1974 (4) | 0.38983 (9) | 0.0458 (5) | |
H9A | 0.5852 | 0.2209 | 0.4160 | 0.069* | |
H9B | 0.5231 | 0.1665 | 0.3565 | 0.069* | |
H9C | 0.3534 | 0.0840 | 0.4005 | 0.069* | |
C10 | 1.2275 (4) | 0.8593 (5) | 0.55230 (11) | 0.0607 (7) | |
H10A | 1.3222 | 0.8071 | 0.5522 | 0.073* | |
H10B | 1.3013 | 1.0012 | 0.5639 | 0.073* | |
C11 | 0.2894 (4) | 0.1053 (5) | 0.19187 (10) | 0.0603 (7) | |
H11A | 0.2513 | 0.2079 | 0.1858 | 0.090* | |
H11B | 0.2631 | 0.0237 | 0.1605 | 0.090* | |
H11C | 0.4328 | 0.1708 | 0.2004 | 0.090* | |
C1' | 0.2961 (3) | 0.3639 (3) | 0.34259 (7) | 0.0322 (4) | |
C2' | 0.0864 (3) | 0.2419 (3) | 0.36637 (7) | 0.0359 (4) | |
C3' | −0.0398 (3) | 0.0420 (3) | 0.35842 (9) | 0.0444 (5) | |
H3' | −0.1583 | −0.0298 | 0.3786 | 0.053* | |
C4' | 0.0103 (3) | −0.0621 (3) | 0.31786 (9) | 0.0439 (5) | |
C5' | 0.1776 (3) | 0.0751 (3) | 0.28038 (8) | 0.0404 (4) | |
C6' | 0.3121 (3) | 0.2697 (3) | 0.29222 (7) | 0.0369 (4) | |
H6' | 0.4177 | 0.3481 | 0.2687 | 0.044* | |
C7' | 0.3057 (3) | 0.5726 (3) | 0.33730 (8) | 0.0401 (4) | |
H7'1 | 0.4457 | 0.6850 | 0.3339 | 0.048* | |
H7'2 | 0.2245 | 0.5745 | 0.3078 | 0.048* | |
C8' | 0.2118 (3) | 0.5766 (4) | 0.39009 (9) | 0.0425 (5) | |
H8' | 0.1629 | 0.6754 | 0.3899 | 0.051* | |
C9' | 0.3607 (4) | 0.6189 (4) | 0.43475 (8) | 0.0425 (5) | |
H9'1 | 0.2987 | 0.6253 | 0.4678 | 0.051* | |
H9'2 | 0.4832 | 0.7511 | 0.4292 | 0.051* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0400 (7) | 0.0791 (11) | 0.0386 (9) | 0.0229 (8) | −0.0077 (7) | −0.0096 (8) |
O2 | 0.0596 (10) | 0.0853 (12) | 0.0309 (9) | 0.0364 (9) | −0.0199 (7) | −0.0184 (8) |
O3 | 0.0414 (7) | 0.0673 (9) | 0.0283 (7) | 0.0294 (7) | 0.0021 (6) | 0.0008 (7) |
O4 | 0.0682 (11) | 0.0391 (8) | 0.0628 (12) | 0.0132 (7) | −0.0149 (9) | 0.0062 (7) |
O5 | 0.0782 (11) | 0.0523 (9) | 0.0327 (9) | 0.0231 (9) | −0.0089 (8) | −0.0164 (7) |
C1 | 0.0410 (9) | 0.0439 (9) | 0.0172 (8) | 0.0215 (8) | −0.0002 (7) | −0.0029 (7) |
C2 | 0.0413 (9) | 0.0500 (10) | 0.0160 (8) | 0.0224 (8) | −0.0003 (7) | −0.0008 (7) |
C3 | 0.0394 (9) | 0.0480 (10) | 0.0258 (10) | 0.0234 (8) | −0.0024 (7) | −0.0072 (8) |
C4 | 0.0532 (11) | 0.0560 (11) | 0.0214 (9) | 0.0338 (9) | −0.0119 (8) | −0.0141 (8) |
C5 | 0.0612 (12) | 0.0594 (12) | 0.0148 (9) | 0.0320 (10) | −0.0023 (8) | −0.0037 (8) |
C6 | 0.0448 (10) | 0.0524 (11) | 0.0186 (9) | 0.0200 (8) | 0.0023 (7) | −0.0027 (8) |
C7 | 0.0362 (8) | 0.0471 (9) | 0.0162 (8) | 0.0208 (7) | 0.0005 (6) | −0.0026 (7) |
C8 | 0.0335 (8) | 0.0417 (9) | 0.0164 (8) | 0.0162 (7) | −0.0003 (6) | −0.0039 (7) |
C9 | 0.0547 (11) | 0.0564 (12) | 0.0353 (12) | 0.0346 (10) | −0.0098 (9) | −0.0097 (9) |
C10 | 0.0530 (13) | 0.0927 (19) | 0.0395 (14) | 0.0388 (13) | −0.0171 (11) | −0.0310 (13) |
C11 | 0.0661 (15) | 0.0802 (17) | 0.0251 (11) | 0.0295 (13) | −0.0038 (10) | −0.0183 (11) |
C1' | 0.0365 (8) | 0.0386 (8) | 0.0151 (8) | 0.0140 (7) | −0.0001 (7) | 0.0003 (6) |
C2' | 0.0367 (9) | 0.0518 (10) | 0.0176 (8) | 0.0209 (8) | −0.0013 (7) | 0.0045 (7) |
C3' | 0.0373 (9) | 0.0525 (11) | 0.0301 (10) | 0.0126 (8) | −0.0008 (8) | 0.0133 (8) |
C4' | 0.0447 (10) | 0.0405 (9) | 0.0348 (11) | 0.0124 (8) | −0.0133 (8) | 0.0052 (8) |
C5' | 0.0517 (10) | 0.0432 (9) | 0.0217 (9) | 0.0203 (8) | −0.0079 (8) | −0.0040 (8) |
C6' | 0.0443 (9) | 0.0428 (9) | 0.0151 (8) | 0.0154 (8) | 0.0013 (7) | −0.0004 (7) |
C7' | 0.0508 (10) | 0.0433 (10) | 0.0222 (10) | 0.0205 (8) | −0.0025 (8) | 0.0027 (7) |
C8' | 0.0510 (10) | 0.0538 (11) | 0.0316 (11) | 0.0329 (9) | −0.0030 (8) | −0.0022 (8) |
C9' | 0.0536 (11) | 0.0582 (11) | 0.0241 (10) | 0.0341 (10) | −0.0044 (8) | −0.0105 (8) |
O1—C3 | 1.372 (3) | C9—H9A | 0.9600 |
O1—C10 | 1.435 (3) | C9—H9B | 0.9600 |
O2—C4 | 1.377 (3) | C9—H9C | 0.9600 |
O2—C10 | 1.416 (4) | C10—H10A | 0.9700 |
O3—C2' | 1.351 (3) | C10—H10B | 0.9700 |
O3—C8' | 1.473 (3) | C11—H11A | 0.9600 |
O4—C4' | 1.224 (3) | C11—H11B | 0.9600 |
O5—C5' | 1.358 (3) | C11—H11C | 0.9600 |
O5—C11 | 1.431 (3) | C1'—C6' | 1.491 (2) |
C1—C6 | 1.392 (3) | C1'—C2' | 1.498 (2) |
C1—C2 | 1.401 (3) | C1'—C7' | 1.541 (3) |
C1—C7 | 1.519 (2) | C2'—C3' | 1.332 (3) |
C2—C3 | 1.369 (3) | C3'—C4' | 1.450 (3) |
C2—H2 | 0.9300 | C3'—H3' | 0.9300 |
C3—C4 | 1.386 (3) | C4'—C5' | 1.499 (3) |
C4—C5 | 1.359 (3) | C5'—C6' | 1.332 (3) |
C5—C6 | 1.402 (3) | C6'—H6' | 0.9300 |
C5—H5 | 0.9300 | C7'—C8' | 1.517 (3) |
C6—H6 | 0.9300 | C7'—H7'1 | 0.9700 |
C7—C9' | 1.537 (3) | C7'—H7'2 | 0.9700 |
C7—C8 | 1.542 (2) | C8'—C9' | 1.508 (3) |
C7—H7 | 0.9800 | C8'—H8' | 0.9800 |
C8—C9 | 1.523 (3) | C9'—H9'1 | 0.9700 |
C8—C1' | 1.583 (2) | C9'—H9'2 | 0.9700 |
C8—H8 | 0.9800 | ||
C3—O1—C10 | 105.20 (19) | O5—C11—H11A | 109.5 |
C4—O2—C10 | 105.84 (19) | O5—C11—H11B | 109.5 |
C2'—O3—C8' | 107.78 (15) | H11A—C11—H11B | 109.5 |
C5'—O5—C11 | 115.64 (19) | O5—C11—H11C | 109.5 |
C6—C1—C2 | 119.65 (18) | H11A—C11—H11C | 109.5 |
C6—C1—C7 | 119.34 (17) | H11B—C11—H11C | 109.5 |
C2—C1—C7 | 120.80 (17) | C6'—C1'—C2' | 111.24 (15) |
C3—C2—C1 | 117.53 (17) | C6'—C1'—C7' | 115.85 (16) |
C3—C2—H2 | 121.2 | C2'—C1'—C7' | 99.03 (15) |
C1—C2—H2 | 121.2 | C6'—C1'—C8 | 111.95 (15) |
C2—C3—O1 | 127.76 (19) | C2'—C1'—C8 | 110.03 (14) |
C2—C3—C4 | 122.06 (18) | C7'—C1'—C8 | 107.97 (15) |
O1—C3—C4 | 110.18 (18) | C3'—C2'—O3 | 124.81 (19) |
C5—C4—O2 | 128.4 (2) | C3'—C2'—C1' | 124.61 (19) |
C5—C4—C3 | 121.93 (18) | O3—C2'—C1' | 110.54 (17) |
O2—C4—C3 | 109.6 (2) | C2'—C3'—C4' | 119.05 (19) |
C4—C5—C6 | 116.67 (18) | C2'—C3'—H3' | 120.5 |
C4—C5—H5 | 121.7 | C4'—C3'—H3' | 120.5 |
C6—C5—H5 | 121.7 | O4—C4'—C3' | 123.4 (2) |
C1—C6—C5 | 122.16 (19) | O4—C4'—C5' | 121.0 (2) |
C1—C6—H6 | 118.9 | C3'—C4'—C5' | 115.52 (18) |
C5—C6—H6 | 118.9 | C6'—C5'—O5 | 126.2 (2) |
C1—C7—C9' | 108.71 (15) | C6'—C5'—C4' | 121.93 (19) |
C1—C7—C8 | 115.04 (15) | O5—C5'—C4' | 111.84 (18) |
C9'—C7—C8 | 112.98 (15) | C5'—C6'—C1' | 121.12 (18) |
C1—C7—H7 | 106.5 | C5'—C6'—H6' | 119.4 |
C9'—C7—H7 | 106.5 | C1'—C6'—H6' | 119.4 |
C8—C7—H7 | 106.5 | C8'—C7'—C1' | 99.15 (16) |
C9—C8—C7 | 109.86 (16) | C8'—C7'—H7'1 | 111.9 |
C9—C8—C1' | 113.33 (15) | C1'—C7'—H7'1 | 111.9 |
C7—C8—C1' | 110.25 (14) | C8'—C7'—H7'2 | 111.9 |
C9—C8—H8 | 107.7 | C1'—C7'—H7'2 | 111.9 |
C7—C8—H8 | 107.7 | H7'1—C7'—H7'2 | 109.6 |
C1'—C8—H8 | 107.7 | O3—C8'—C9' | 108.35 (18) |
C8—C9—H9A | 109.5 | O3—C8'—C7' | 102.87 (17) |
C8—C9—H9B | 109.5 | C9'—C8'—C7' | 111.03 (17) |
H9A—C9—H9B | 109.5 | O3—C8'—H8' | 111.4 |
C8—C9—H9C | 109.5 | C9'—C8'—H8' | 111.4 |
H9A—C9—H9C | 109.5 | C7'—C8'—H8' | 111.4 |
H9B—C9—H9C | 109.5 | C8'—C9'—C7 | 111.32 (16) |
O2—C10—O1 | 109.09 (19) | C8'—C9'—H9'1 | 109.4 |
O2—C10—H10A | 109.9 | C7—C9'—H9'1 | 109.4 |
O1—C10—H10A | 109.9 | C8'—C9'—H9'2 | 109.4 |
O2—C10—H10B | 109.9 | C7—C9'—H9'2 | 109.4 |
O1—C10—H10B | 109.9 | H9'1—C9'—H9'2 | 108.0 |
H10A—C10—H10B | 108.3 | ||
C6—C1—C2—C3 | −0.1 (3) | C8'—O3—C2'—C1' | 3.3 (2) |
C7—C1—C2—C3 | 174.48 (18) | C6'—C1'—C2'—C3' | 26.0 (3) |
C1—C2—C3—O1 | −179.1 (2) | C7'—C1'—C2'—C3' | 148.33 (19) |
C1—C2—C3—C4 | 0.9 (3) | C8—C1'—C2'—C3' | −98.7 (2) |
C10—O1—C3—C2 | −177.6 (2) | C6'—C1'—C2'—O3 | −151.92 (16) |
C10—O1—C3—C4 | 2.3 (2) | C7'—C1'—C2'—O3 | −29.55 (19) |
C10—O2—C4—C5 | 179.4 (2) | C8—C1'—C2'—O3 | 83.43 (18) |
C10—O2—C4—C3 | −0.5 (2) | O3—C2'—C3'—C4' | 167.15 (18) |
C2—C3—C4—C5 | −1.2 (3) | C1'—C2'—C3'—C4' | −10.4 (3) |
O1—C3—C4—C5 | 178.9 (2) | C2'—C3'—C4'—O4 | 171.1 (2) |
C2—C3—C4—O2 | 178.76 (19) | C2'—C3'—C4'—C5' | −12.7 (3) |
O1—C3—C4—O2 | −1.2 (2) | C11—O5—C5'—C6' | −15.0 (3) |
O2—C4—C5—C6 | −179.4 (2) | C11—O5—C5'—C4' | 164.9 (2) |
C3—C4—C5—C6 | 0.5 (3) | O4—C4'—C5'—C6' | −163.9 (2) |
C2—C1—C6—C5 | −0.5 (3) | C3'—C4'—C5'—C6' | 19.8 (3) |
C7—C1—C6—C5 | −175.19 (19) | O4—C4'—C5'—O5 | 16.2 (3) |
C4—C5—C6—C1 | 0.3 (3) | C3'—C4'—C5'—O5 | −160.10 (18) |
C6—C1—C7—C9' | 91.1 (2) | O5—C5'—C6'—C1' | 176.8 (2) |
C2—C1—C7—C9' | −83.5 (2) | C4'—C5'—C6'—C1' | −3.1 (3) |
C6—C1—C7—C8 | −141.08 (18) | C2'—C1'—C6'—C5' | −18.2 (3) |
C2—C1—C7—C8 | 44.3 (2) | C7'—C1'—C6'—C5' | −130.2 (2) |
C1—C7—C8—C9 | 64.9 (2) | C8—C1'—C6'—C5' | 105.4 (2) |
C9'—C7—C8—C9 | −169.50 (17) | C6'—C1'—C7'—C8' | 161.05 (16) |
C1—C7—C8—C1' | −169.55 (15) | C2'—C1'—C7'—C8' | 42.06 (18) |
C9'—C7—C8—C1' | −43.9 (2) | C8—C1'—C7'—C8' | −72.52 (17) |
C4—O2—C10—O1 | 2.0 (3) | C2'—O3—C8'—C9' | −92.49 (18) |
C3—O1—C10—O2 | −2.6 (3) | C2'—O3—C8'—C7' | 25.1 (2) |
C9—C8—C1'—C6' | −46.7 (2) | C1'—C7'—C8'—O3 | −41.81 (18) |
C7—C8—C1'—C6' | −170.28 (15) | C1'—C7'—C8'—C9' | 73.9 (2) |
C9—C8—C1'—C2' | 77.6 (2) | O3—C8'—C9'—C7 | 51.3 (2) |
C7—C8—C1'—C2' | −46.0 (2) | C7'—C8'—C9'—C7 | −60.9 (2) |
C9—C8—C1'—C7' | −175.35 (17) | C1—C7—C9'—C8' | 172.37 (18) |
C7—C8—C1'—C7' | 61.04 (19) | C8—C7—C9'—C8' | 43.4 (2) |
C8'—O3—C2'—C3' | −174.57 (18) |
Experimental details
Crystal data | |
Chemical formula | C20H20O5 |
Mr | 340.36 |
Crystal system, space group | Trigonal, P31 |
Temperature (K) | 297 |
a, c (Å) | 7.5210 (6), 25.2821 (13) |
V (Å3) | 1238.50 (15) |
Z | 3 |
Radiation type | Cu Kα |
µ (mm−1) | 0.81 |
Crystal size (mm) | 0.45 × 0.34 × 0.34 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.614, 0.724 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4948, 1748, 1727 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.626 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.085, 1.10 |
No. of reflections | 1748 |
No. of parameters | 229 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.23, −0.17 |
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.
O1—C10 | 1.435 (3) | O3—C8' | 1.473 (3) |
O2—C10 | 1.416 (4) | O4—C4' | 1.224 (3) |
O3—C2' | 1.351 (3) | C8—C1' | 1.583 (2) |
C3—O1—C10 | 105.20 (19) | C2'—O3—C8' | 107.78 (15) |
C4—O2—C10 | 105.84 (19) | ||
C2—C1—C7—C8 | 44.3 (2) | C3'—C4'—C5'—C6' | 19.8 (3) |
C8'—O3—C2'—C1' | 3.3 (2) | C4'—C5'—C6'—C1' | −3.1 (3) |
C6'—C1'—C2'—C3' | 26.0 (3) | C2'—C1'—C6'—C5' | −18.2 (3) |
C7'—C1'—C2'—O3 | −29.55 (19) | C2'—C1'—C7'—C8' | 42.06 (18) |
C1'—C2'—C3'—C4' | −10.4 (3) | C2'—O3—C8'—C7' | 25.1 (2) |
C2'—C3'—C4'—C5' | −12.7 (3) | C1'—C7'—C8'—O3 | −41.81 (18) |
The title neolignan, (I), has been previously reported from Piper futokadsura (Ogiso et al., 1968), Magnolia denudata (Iida et al., 1982), Magnolia liliflora (Iida & Ito, 1983; Talapatra et al., 1982) and other plants (Shizuri & Yamamura, 1983). The crystal structure of an orthorhombic (P212121) polymorph has been previously reported (Roychowdhury & Gosh, 1984), but its coordinates are not available. The conformation of the molecule in the orthorhombic polymorph is reported by Roychowdhury & Gosh to be somewhat different from what we find, even in the portion of the molecule with three fused rings, which might be expected to be rather rigid. They report the tetrahydrofuran ring to be a half chair, while in the present trigonal polymorph, it is clearly envelope, with C7' lying 0.689 (3) Å out of the best plane of the other four atoms. Further, they report that all atoms of the semiquinone ring `except (the spiro C atom) lie on a plane since the torsion angles associated with this group are within 6° of zero'. We find larger deviations, with torsion angles about C3'—C4' and C4'—C5' differing from zero by 12.7 (3) and 19.8 (3)°, respectively. In the present structure, the six atoms of the semiquinone ring deviate from coplanarity by distances ranging from -0.0310 (14) Å for C3' to 0.1603 (13) Å for C1'. We find the C8—C1' bond to be somewhat elongated at 1.583 (2) Å, which was also noted by Roychowdhury & Gosh (1.589 Å).
In the title structure, a short intermolecular C4'···O2(y-x, 1 - x, z - 1/3) contact exists with a distance of 2.968 (3) Å.