Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100017406/bm1432sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100017406/bm1432Isup2.hkl |
CCDC reference: 160006
Nodosin was extracted from the Chinese medicinal plant Rabdosia serra (Maxim.) Hara (Family: Labiatae). The extracting solvent was aqueous ethanol (70%) and the recrystallizing solvent was acetone.
The hydroxy hydrogen atoms were freely refined and the remaining hydrogen atoms were initially placed in calculated positions and thereafter allowed to ride on their attached atoms with common isotropic temperature factors which converged to 0.029 (2) Å2 (non-methyl H atoms) and 0.051 (5) Å2 (methyl H atoms). Constrained C—H distances were 0.95, 1.00, 0.99 and 0.98 Å for sp2, methine, methylene and methyl groups, respectively.
Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997).
C20H26O6 | Dx = 1.330 Mg m−3 |
Mr = 362.41 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 6964 reflections |
a = 7.474 (3) Å | θ = 1.9–27.5° |
b = 15.262 (6) Å | µ = 0.10 mm−1 |
c = 15.870 (8) Å | T = 150 K |
V = 1810.3 (14) Å3 | Block, colourless |
Z = 4 | 0.1 × 0.08 × 0.08 mm |
F(000) = 776 |
Enraf Nonius kappaCCD area detector diffractometer | 2220 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 1534 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.072 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 1.9° |
ϕ and ω scans to fill Ewald sphere | h = −6→9 |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | k = −18→19 |
Tmin = 0.95, Tmax = 0.99 | l = −20→20 |
6964 measured reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.047 | w = 1/[σ2(Fo2) + (0.0392P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.103 | (Δ/σ)max = 0.001 |
S = 1.02 | Δρmax = 0.21 e Å−3 |
2220 reflections | Δρmin = −0.21 e Å−3 |
246 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.022 (2) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983) |
Secondary atom site location: difference Fourier map | Absolute structure parameter: not reliably determined |
C20H26O6 | V = 1810.3 (14) Å3 |
Mr = 362.41 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 7.474 (3) Å | µ = 0.10 mm−1 |
b = 15.262 (6) Å | T = 150 K |
c = 15.870 (8) Å | 0.1 × 0.08 × 0.08 mm |
Enraf Nonius kappaCCD area detector diffractometer | 2220 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1534 reflections with I > 2σ(I) |
Tmin = 0.95, Tmax = 0.99 | Rint = 0.072 |
6964 measured reflections |
R[F2 > 2σ(F2)] = 0.047 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.103 | Δρmax = 0.21 e Å−3 |
S = 1.02 | Δρmin = −0.21 e Å−3 |
2220 reflections | Absolute structure: Flack (1983) |
246 parameters | Absolute structure parameter: not reliably determined |
0 restraints |
Experimental. Please note cell_measurement_ fields are not relevant to area detector data, the entire data set is used to refine the cell, which is indexed from all observed reflections in a 10 degree phi range. |
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 | 0.1276 (3) | −0.02306 (14) | −0.24840 (15) | 0.0318 (6) | |
H1 | 0.216 (5) | −0.050 (2) | −0.278 (2) | 0.049 (12)* | |
O2 | 0.3339 (3) | 0.05284 (14) | −0.16645 (13) | 0.0304 (6) | |
O3 | 0.0567 (3) | 0.16159 (13) | 0.04022 (13) | 0.0281 (5) | |
O4 | 0.0819 (3) | 0.06953 (15) | 0.14519 (14) | 0.0376 (6) | |
O5 | 0.1684 (3) | −0.09942 (15) | 0.06004 (14) | 0.0381 (6) | |
O6 | −0.3190 (3) | 0.08013 (14) | −0.12022 (14) | 0.0294 (6) | |
H6 | −0.423 (5) | 0.070 (2) | −0.140 (2) | 0.037 (11)* | |
C1 | −0.0074 (4) | 0.17544 (19) | −0.0467 (2) | 0.0250 (7) | |
H1A | −0.1411 | 0.1723 | −0.0468 | 0.029 (2)* | |
C2 | 0.0479 (5) | 0.26616 (19) | −0.0727 (2) | 0.0298 (8) | |
H2A | 0.1791 | 0.2729 | −0.0668 | 0.029 (2)* | |
H2B | −0.0112 | 0.3102 | −0.0364 | 0.029 (2)* | |
C3 | −0.0067 (5) | 0.2799 (2) | −0.1642 (2) | 0.0322 (8) | |
H3A | −0.1367 | 0.2691 | −0.1700 | 0.029 (2)* | |
H3B | 0.0168 | 0.3415 | −0.1803 | 0.029 (2)* | |
C4 | 0.0943 (4) | 0.2193 (2) | −0.2236 (2) | 0.0293 (8) | |
C5 | 0.0602 (4) | 0.12166 (18) | −0.19773 (18) | 0.0223 (7) | |
H5 | −0.0589 | 0.1033 | −0.2204 | 0.029 (2)* | |
C6 | 0.2019 (4) | 0.0596 (2) | −0.2318 (2) | 0.0256 (7) | |
H6A | 0.2567 | 0.0843 | −0.2841 | 0.029 (2)* | |
C7 | 0.2643 (4) | 0.0852 (2) | −0.08756 (19) | 0.0274 (7) | |
H7A | 0.3253 | 0.1402 | −0.0713 | 0.029 (2)* | |
H7B | 0.2825 | 0.0415 | −0.0423 | 0.029 (2)* | |
C8 | 0.0649 (4) | 0.10143 (19) | −0.10162 (18) | 0.0217 (7) | |
C9 | 0.0350 (4) | 0.0818 (2) | 0.07301 (19) | 0.0265 (8) | |
C10 | −0.0567 (4) | 0.0113 (2) | 0.02202 (19) | 0.0241 (7) | |
C11 | −0.0379 (4) | 0.01631 (19) | −0.07722 (19) | 0.0223 (7) | |
H11 | 0.0416 | −0.0335 | −0.0937 | 0.029 (2)* | |
C12 | −0.2170 (4) | 0.0005 (2) | −0.12226 (19) | 0.0236 (7) | |
H12 | −0.1907 | −0.0135 | −0.1826 | 0.029 (2)* | |
C13 | −0.3202 (4) | −0.07723 (19) | −0.08453 (19) | 0.0267 (7) | |
H13A | −0.2770 | −0.1318 | −0.1114 | 0.029 (2)* | |
H13B | −0.4484 | −0.0707 | −0.0989 | 0.029 (2)* | |
C14 | −0.3028 (4) | −0.0869 (2) | 0.01186 (19) | 0.0283 (8) | |
H14 | −0.4148 | −0.1110 | 0.0374 | 0.029 (2)* | |
C15 | −0.2544 (4) | 0.0032 (2) | 0.0495 (2) | 0.0285 (7) | |
H15A | −0.2665 | 0.0035 | 0.1117 | 0.029 (2)* | |
H15B | −0.3288 | 0.0506 | 0.0253 | 0.029 (2)* | |
C16 | 0.0147 (5) | −0.0800 (2) | 0.0440 (2) | 0.0300 (8) | |
C17 | −0.1414 (4) | −0.1404 (2) | 0.0360 (2) | 0.0305 (8) | |
C18 | −0.1260 (5) | −0.2261 (2) | 0.0489 (2) | 0.0408 (9) | |
H18A | −0.0134 | −0.2505 | 0.0637 | 0.029 (2)* | |
H18B | −0.2277 | −0.2630 | 0.0434 | 0.029 (2)* | |
C19 | 0.0169 (5) | 0.2312 (2) | −0.3125 (2) | 0.0389 (9) | |
H19A | 0.0808 | 0.1929 | −0.3519 | 0.051 (5)* | |
H19B | 0.0310 | 0.2923 | −0.3300 | 0.051 (5)* | |
H19C | −0.1104 | 0.2158 | −0.3122 | 0.051 (5)* | |
C20 | 0.2939 (5) | 0.2458 (2) | −0.2266 (2) | 0.0344 (9) | |
H20A | 0.3468 | 0.2389 | −0.1705 | 0.051 (5)* | |
H20B | 0.3041 | 0.3070 | −0.2445 | 0.051 (5)* | |
H20C | 0.3573 | 0.2082 | −0.2667 | 0.051 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0284 (14) | 0.0306 (13) | 0.0364 (14) | −0.0046 (11) | 0.0065 (11) | −0.0119 (11) |
O2 | 0.0204 (13) | 0.0423 (13) | 0.0284 (12) | 0.0020 (11) | −0.0007 (10) | −0.0082 (11) |
O3 | 0.0332 (13) | 0.0307 (12) | 0.0202 (11) | −0.0024 (10) | −0.0011 (11) | −0.0026 (10) |
O4 | 0.0456 (16) | 0.0412 (14) | 0.0259 (13) | 0.0028 (12) | −0.0097 (11) | −0.0006 (11) |
O5 | 0.0378 (16) | 0.0384 (13) | 0.0382 (15) | 0.0109 (12) | −0.0082 (12) | 0.0029 (11) |
O6 | 0.0169 (13) | 0.0279 (13) | 0.0433 (14) | 0.0016 (11) | −0.0044 (11) | 0.0024 (11) |
C1 | 0.0274 (18) | 0.0286 (16) | 0.0191 (16) | 0.0018 (14) | −0.0004 (14) | −0.0016 (15) |
C2 | 0.034 (2) | 0.0253 (17) | 0.0303 (19) | −0.0004 (15) | 0.0051 (16) | −0.0032 (15) |
C3 | 0.033 (2) | 0.0257 (17) | 0.037 (2) | −0.0003 (15) | 0.0000 (16) | 0.0018 (16) |
C4 | 0.0278 (19) | 0.0301 (17) | 0.0301 (18) | −0.0040 (15) | −0.0022 (15) | 0.0019 (15) |
C5 | 0.0193 (18) | 0.0259 (17) | 0.0216 (16) | −0.0019 (14) | 0.0003 (14) | −0.0026 (13) |
C6 | 0.0229 (18) | 0.0269 (17) | 0.0270 (17) | −0.0009 (14) | 0.0024 (14) | −0.0021 (14) |
C7 | 0.0222 (18) | 0.0350 (19) | 0.0249 (16) | −0.0001 (15) | −0.0023 (14) | −0.0039 (15) |
C8 | 0.0146 (16) | 0.0248 (16) | 0.0256 (17) | 0.0006 (14) | 0.0005 (13) | −0.0020 (14) |
C9 | 0.0251 (19) | 0.0294 (19) | 0.0251 (18) | 0.0049 (15) | 0.0022 (14) | −0.0003 (16) |
C10 | 0.0218 (17) | 0.0252 (16) | 0.0254 (17) | 0.0036 (14) | −0.0013 (14) | −0.0002 (14) |
C11 | 0.0198 (18) | 0.0259 (16) | 0.0212 (16) | 0.0019 (14) | −0.0003 (13) | −0.0012 (14) |
C12 | 0.0198 (18) | 0.0250 (16) | 0.0261 (17) | 0.0003 (15) | 0.0001 (13) | −0.0012 (14) |
C13 | 0.0207 (18) | 0.0268 (17) | 0.0326 (18) | −0.0002 (15) | −0.0011 (14) | −0.0018 (15) |
C14 | 0.027 (2) | 0.0257 (18) | 0.0322 (18) | −0.0005 (15) | 0.0046 (15) | 0.0020 (15) |
C15 | 0.0265 (17) | 0.0292 (17) | 0.0297 (18) | 0.0017 (15) | 0.0036 (14) | 0.0011 (16) |
C16 | 0.037 (2) | 0.0335 (19) | 0.0191 (16) | 0.0072 (17) | 0.0004 (15) | −0.0001 (16) |
C17 | 0.035 (2) | 0.0272 (18) | 0.0293 (19) | 0.0026 (16) | 0.0046 (16) | 0.0005 (16) |
C18 | 0.050 (3) | 0.033 (2) | 0.039 (2) | 0.0042 (18) | 0.0048 (18) | 0.0044 (17) |
C19 | 0.045 (2) | 0.040 (2) | 0.032 (2) | −0.0072 (19) | −0.0065 (17) | 0.0079 (17) |
C20 | 0.037 (2) | 0.0340 (19) | 0.0326 (19) | −0.0106 (16) | 0.0038 (16) | 0.0024 (16) |
O1—C6 | 1.403 (4) | C5—C6 | 1.521 (4) |
O2—C6 | 1.435 (4) | C5—C8 | 1.557 (4) |
O2—C7 | 1.443 (4) | C7—C8 | 1.527 (4) |
O3—C9 | 1.335 (4) | C8—C11 | 1.558 (4) |
O3—C1 | 1.475 (4) | C9—C10 | 1.510 (4) |
O4—C9 | 1.212 (4) | C10—C16 | 1.533 (4) |
O5—C16 | 1.213 (4) | C10—C15 | 1.546 (4) |
O6—C12 | 1.435 (4) | C10—C11 | 1.583 (4) |
C1—C2 | 1.503 (4) | C11—C12 | 1.537 (4) |
C1—C8 | 1.526 (4) | C12—C13 | 1.536 (4) |
C2—C3 | 1.522 (5) | C13—C14 | 1.542 (4) |
C3—C4 | 1.521 (4) | C14—C17 | 1.507 (5) |
C4—C19 | 1.535 (4) | C14—C15 | 1.542 (4) |
C4—C20 | 1.546 (5) | C16—C17 | 1.492 (5) |
C4—C5 | 1.566 (4) | C17—C18 | 1.329 (4) |
C6—O2—C7 | 110.8 (2) | O4—C9—O3 | 118.3 (3) |
C9—O3—C1 | 117.1 (2) | O4—C9—C10 | 121.9 (3) |
O3—C1—C2 | 107.4 (2) | O3—C9—C10 | 119.7 (3) |
O3—C1—C8 | 108.2 (2) | C9—C10—C16 | 111.6 (3) |
C2—C1—C8 | 115.3 (3) | C9—C10—C15 | 109.9 (3) |
C1—C2—C3 | 108.4 (3) | C16—C10—C15 | 101.2 (3) |
C4—C3—C2 | 112.0 (3) | C9—C10—C11 | 117.3 (3) |
C3—C4—C19 | 108.1 (3) | C16—C10—C11 | 103.8 (2) |
C3—C4—C20 | 109.8 (3) | C15—C10—C11 | 111.7 (2) |
C19—C4—C20 | 107.7 (3) | C12—C11—C8 | 116.4 (2) |
C3—C4—C5 | 109.6 (3) | C12—C11—C10 | 112.2 (2) |
C19—C4—C5 | 106.9 (3) | C8—C11—C10 | 109.3 (2) |
C20—C4—C5 | 114.4 (3) | O6—C12—C13 | 112.3 (2) |
C6—C5—C8 | 102.1 (2) | O6—C12—C11 | 108.6 (2) |
C6—C5—C4 | 112.7 (3) | C13—C12—C11 | 112.2 (3) |
C8—C5—C4 | 116.2 (2) | C12—C13—C14 | 114.7 (3) |
O1—C6—O2 | 110.1 (2) | C17—C14—C15 | 101.4 (3) |
O1—C6—C5 | 110.6 (3) | C17—C14—C13 | 111.8 (3) |
O2—C6—C5 | 105.5 (2) | C15—C14—C13 | 108.6 (3) |
O2—C7—C8 | 106.3 (2) | C14—C15—C10 | 100.8 (3) |
C1—C8—C7 | 112.5 (3) | O5—C16—C17 | 127.4 (3) |
C1—C8—C5 | 113.9 (2) | O5—C16—C10 | 126.8 (3) |
C7—C8—C5 | 101.4 (2) | C17—C16—C10 | 105.7 (3) |
C1—C8—C11 | 107.5 (2) | C18—C17—C16 | 121.8 (3) |
C7—C8—C11 | 108.0 (3) | C18—C17—C14 | 130.0 (3) |
C5—C8—C11 | 113.4 (2) | C16—C17—C14 | 108.2 (3) |
C9—O3—C1—C2 | −174.3 (3) | O4—C9—C10—C11 | −154.2 (3) |
C9—O3—C1—C8 | −49.2 (3) | O3—C9—C10—C11 | 29.7 (4) |
O3—C1—C2—C3 | 176.5 (2) | C1—C8—C11—C12 | 86.0 (3) |
C8—C1—C2—C3 | 55.8 (4) | C7—C8—C11—C12 | −152.4 (3) |
C1—C2—C3—C4 | −65.1 (3) | C5—C8—C11—C12 | −40.9 (4) |
C2—C3—C4—C19 | 174.3 (3) | C1—C8—C11—C10 | −42.5 (3) |
C2—C3—C4—C20 | −68.5 (3) | C7—C8—C11—C10 | 79.1 (3) |
C2—C3—C4—C5 | 58.1 (4) | C5—C8—C11—C10 | −169.3 (2) |
C3—C4—C5—C6 | −159.8 (3) | C9—C10—C11—C12 | −135.2 (3) |
C19—C4—C5—C6 | 83.3 (3) | C16—C10—C11—C12 | 101.2 (3) |
C20—C4—C5—C6 | −35.9 (4) | C15—C10—C11—C12 | −7.1 (4) |
C3—C4—C5—C8 | −42.5 (4) | C9—C10—C11—C8 | −4.4 (4) |
C19—C4—C5—C8 | −159.4 (3) | C16—C10—C11—C8 | −128.0 (3) |
C20—C4—C5—C8 | 81.4 (4) | C15—C10—C11—C8 | 123.7 (3) |
C7—O2—C6—O1 | −103.5 (3) | C8—C11—C12—O6 | −46.8 (3) |
C7—O2—C6—C5 | 15.7 (3) | C10—C11—C12—O6 | 80.2 (3) |
C8—C5—C6—O1 | 86.3 (3) | C8—C11—C12—C13 | −171.5 (2) |
C4—C5—C6—O1 | −148.3 (3) | C10—C11—C12—C13 | −44.4 (3) |
C8—C5—C6—O2 | −32.7 (3) | O6—C12—C13—C14 | −86.2 (3) |
C4—C5—C6—O2 | 92.7 (3) | C11—C12—C13—C14 | 36.4 (4) |
C6—O2—C7—C8 | 8.5 (3) | C12—C13—C14—C17 | −87.3 (3) |
O3—C1—C8—C7 | −47.2 (3) | C12—C13—C14—C15 | 23.7 (4) |
C2—C1—C8—C7 | 73.1 (3) | C17—C14—C15—C10 | 44.5 (3) |
O3—C1—C8—C5 | −161.8 (2) | C13—C14—C15—C10 | −73.3 (3) |
C2—C1—C8—C5 | −41.5 (4) | C9—C10—C15—C14 | −163.4 (2) |
O3—C1—C8—C11 | 71.6 (3) | C16—C10—C15—C14 | −45.3 (3) |
C2—C1—C8—C11 | −168.1 (3) | C11—C10—C15—C14 | 64.6 (3) |
O2—C7—C8—C1 | −150.2 (2) | C9—C10—C16—O5 | −37.8 (4) |
O2—C7—C8—C5 | −28.1 (3) | C15—C10—C16—O5 | −154.6 (3) |
O2—C7—C8—C11 | 91.3 (3) | C11—C10—C16—O5 | 89.5 (4) |
C6—C5—C8—C1 | 157.6 (3) | C9—C10—C16—C17 | 145.8 (3) |
C4—C5—C8—C1 | 34.5 (4) | C15—C10—C16—C17 | 29.0 (3) |
C6—C5—C8—C7 | 36.5 (3) | C11—C10—C16—C17 | −86.9 (3) |
C4—C5—C8—C7 | −86.5 (3) | O5—C16—C17—C18 | 2.1 (5) |
C6—C5—C8—C11 | −79.0 (3) | C10—C16—C17—C18 | 178.5 (3) |
C4—C5—C8—C11 | 157.9 (3) | O5—C16—C17—C14 | −177.6 (3) |
C1—O3—C9—O4 | −177.9 (3) | C10—C16—C17—C14 | −1.2 (3) |
C1—O3—C9—C10 | −1.7 (4) | C15—C14—C17—C18 | 153.2 (4) |
O4—C9—C10—C16 | −34.6 (4) | C13—C14—C17—C18 | −91.3 (4) |
O3—C9—C10—C16 | 149.3 (3) | C15—C14—C17—C16 | −27.1 (3) |
O4—C9—C10—C15 | 76.8 (4) | C13—C14—C17—C16 | 88.4 (3) |
O3—C9—C10—C15 | −99.2 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O4i | 0.91 (3) | 1.96 (4) | 2.841 (3) | 162 (3) |
O6—H6···O2ii | 0.85 (4) | 1.88 (4) | 2.728 (3) | 171 (3) |
Symmetry codes: (i) −x+1/2, −y, z−1/2; (ii) x−1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C20H26O6 |
Mr | 362.41 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 150 |
a, b, c (Å) | 7.474 (3), 15.262 (6), 15.870 (8) |
V (Å3) | 1810.3 (14) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.1 × 0.08 × 0.08 |
Data collection | |
Diffractometer | Enraf Nonius kappaCCD area detector diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.95, 0.99 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6964, 2220, 1534 |
Rint | 0.072 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.103, 1.02 |
No. of reflections | 2220 |
No. of parameters | 246 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.21, −0.21 |
Absolute structure | Flack (1983) |
Absolute structure parameter | not reliably determined |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), DENZO and COLLECT, SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997).
O1—C6 | 1.403 (4) | C1—C2 | 1.503 (4) |
O5—C16 | 1.213 (4) | C10—C11 | 1.583 (4) |
O6—C12 | 1.435 (4) | ||
C7—C8—C5 | 101.4 (2) | O5—C16—C10 | 126.8 (3) |
C16—C10—C15 | 101.2 (3) | C17—C16—C10 | 105.7 (3) |
C9—C10—C11 | 117.3 (3) | C18—C17—C16 | 121.8 (3) |
C12—C11—C8 | 116.4 (2) | C18—C17—C14 | 130.0 (3) |
O5—C16—C17 | 127.4 (3) | C16—C17—C14 | 108.2 (3) |
C1—O3—C9—C10 | −1.7 (4) | C9—C10—C11—C8 | −4.4 (4) |
C15—C10—C11—C12 | −7.1 (4) | C10—C16—C17—C14 | −1.2 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O4i | .91 (3) | 1.96 (4) | 2.841 (3) | 162 (3) |
O6—H6···O2ii | .85 (4) | 1.88 (4) | 2.728 (3) | 171 (3) |
Symmetry codes: (i) −x+1/2, −y, z−1/2; (ii) x−1, y, z. |
The diterpenoid nodosin, (I), has been found in Rabdosia plants (Takeda et al., 1982) and possesses antitumour activity against P 388 lymphocytic leukemia innoculated into mice (Nagao et al., 1982). The X-ray structure analysis shows that nodosin is a structural isomer of enmein (Fujita et al., 1976) with the β-hydroxy group attached to C12 (nodosin) rather than C3 (enmein). \sch
From the assumed absolute stereochemistry shown in Fig. 1, the eight chiral centres present are S for C1, C8, C10, C11 and C14, and R for C5, C6 and C12. The ring conformations (see scheme) approximate to chair, screw-boat, boat, C15 envelope and half-chair For A—E, respectively.
Details of two well defined intermolecular hydrogen bonds are shown in Table 2. Here the two hydroxy groups O1 and O6 act as donor atoms and O2 and O4 act as acceptor atoms. Within the molecule, O6 is also close to H1A (2.26 Å), H5 (2.54 Å) and H15B (2.35 Å) and these interactions result in a longer O6—C12 of 1.435 (4) Å compared with 01-C6 of 1.403 (3) Å. As shown in Fig. 2 the two independent hydrogen bonds result in an arrangement such that each molecule is held in the crystal by four intermolecular hydrogen bonds. The hydrogen bonding pattern is two-dimensional as there are no hydrogen bonds linking molecules in the direction of the b axis.
Some geometrical features of the molecule determined by PLATON (Spek, 1998) are shown in Table 1. Here the longest bond, C10—C11 1.58 (4) Å, is located where in-plane bending due to ring strain is most evident. The deviations from ideal sp3 angular values around C10 are shown by C16—C10—C15 101.2 (3)° and C9—C10—C11 117.3 (3)°. Table 1 also shows the endocyclic torsion angles that describe the somewhat planar portions of the fused rings.
Similar structures based on spectroscopic evidence have been reported (Takeda et al., 1986) and the absolute configuration of a related structure, acetyl-bromoacetyl-dihydroenmein (Natsume & Iltaka, 1966) is known. Unfortunately the name, nodosin, has also been applied to a glycosylisoflavone (Ilyas et al., 1994).