Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807021320/at2283sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807021320/at2283Isup2.hkl |
CCDC reference: 651565
Dried powder of Salvia miltiorrhiza Bunge was exacted with EtOH and the extract was concentrated in vacuo. The residue was subjected to silical-gel coloumn chromatography. Elution with petroleum ether-ethyl acetate (9:1v/v) yielded the title compound. The identity of (I) was confirmed by NMR spectroscopy. 1H NMR in CDCl3 (400 MHz):1.30 (s, 6H), 1.65 (m, 2H), 1.78 (m, 2H), 2.25(d,1.3 Hz, 3H), 3.18 (t, 6 Hz, 2H), 7.21 (q,1.3 Hz,1H), 7.53 (d, AB, 8 Hz,1H), 7.62(d, AB, 8 Hz,1H). 13C NMR in CDCl3 (100 MHz): 8.96, 19.33, 30.01, 32.03, 34.86, 38.07, 120.11, 120.43, 121.35, 126.71, 127.66, 133.64, 141.49, 144.66, 150.35, 161.91, 175.96, 183.83.
All H atoms were positioned geometrically and refined using a riding model, in the range of 0.95–0.98 Å, with Uiso(H) = 1.2Ueq(carrier) or Uiso(H) = 1.5Ueq(methyl C). The methylene groups C15 and C16, and five H atoms H3a, H3b, H3c, H14a, H14b are found to be disordered. The molecular were located on mirror plane (the molecule has no such symmetry), so C15, C16 were disordered in two position. All the two site occupancies were refined to 0.5:0.5.
Tanshinone IIA is one of the major active constitutes isolated from the traditional Chinese medicinal herb, Salvia miltiorrhiza Bunge, which has been widely used in China to treat coronary heart diseases (Chang et al., 1991), antitumour (Ryu et al., 1997), angina pectoris and myocardial infarction (Xue et al., 1999). Tanshinone IIA is also most effective and has been used as a qualitycontroller for some medicine. We report here the crystal structure (I)(Fig. 1).
The crystal structure of (I) illustrated in Fig. 1 shows that the C12—C17 ring has a twisted conformation. Also, the C4—C9 are essentially coplanar with the aromatic rings. An intermolecular C—H···O hydrogen bond links the molecules into a chain extending along the b axis. No π-π interactions are observed.
For related literature, see: Chang et al. (1991); Ryu et al. (1997); Xue et al. (1999).
Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.
Fig. 1. A view of the molecular of (I). Displacement ellipsoids are drawn at the 30% probability level. One disorder component is shown for clarity. |
C19H18O3 | Dx = 1.337 Mg m−3 |
Mr = 294.33 | Melting point = 209.0–210.0 K |
Orthorhombic, Pmna | Mo Kα radiation, λ = 0.71070 Å |
Hall symbol: -P 2ac 2 | Cell parameters from 2823 reflections |
a = 6.5579 (11) Å | θ = 2.2–27.9° |
b = 9.1687 (15) Å | µ = 0.09 mm−1 |
c = 24.328 (4) Å | T = 113 K |
V = 1462.8 (4) Å3 | Prism, colourless |
Z = 4 | 0.24 × 0.20 × 0.10 mm |
F(000) = 624 |
Rigaku Saturn diffractometer | 1404 independent reflections |
Radiation source: rotating anode | 1343 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.044 |
Detector resolution: 7.31 pixels mm-1 | θmax = 25.0°, θmin = 2.2° |
ω scans | h = −7→7 |
Absorption correction: multi-scan (SADABS; Sheldrick,1996) | k = −10→10 |
Tmin = 0.968, Tmax = 0.991 | l = −28→28 |
10602 measured reflections |
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)] = 0.057 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.139 | H-atom parameters constrained |
S = 1.17 | w = 1/[σ2(Fo2) + (0.0606P)2 + 0.879P] where P = (Fo2 + 2Fc2)/3 |
1404 reflections | (Δ/σ)max = 0.001 |
139 parameters | Δρmax = 0.22 e Å−3 |
1 restraint | Δρmin = −0.22 e Å−3 |
C19H18O3 | V = 1462.8 (4) Å3 |
Mr = 294.33 | Z = 4 |
Orthorhombic, Pmna | Mo Kα radiation |
a = 6.5579 (11) Å | µ = 0.09 mm−1 |
b = 9.1687 (15) Å | T = 113 K |
c = 24.328 (4) Å | 0.24 × 0.20 × 0.10 mm |
Rigaku Saturn diffractometer | 1404 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick,1996) | 1343 reflections with I > 2σ(I) |
Tmin = 0.968, Tmax = 0.991 | Rint = 0.044 |
10602 measured reflections |
R[F2 > 2σ(F2)] = 0.057 | 1 restraint |
wR(F2) = 0.139 | H-atom parameters constrained |
S = 1.17 | Δρmax = 0.22 e Å−3 |
1404 reflections | Δρmin = −0.22 e Å−3 |
139 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 | Occ. (<1) | |
C1 | 0.0000 | 0.8407 (3) | 0.29609 (10) | 0.0249 (6) | |
H1 | 0.0000 | 0.9428 | 0.3029 | 0.030* | |
C2 | 0.0000 | 0.7377 (3) | 0.33594 (11) | 0.0240 (6) | |
C3 | 0.0000 | 0.7590 (3) | 0.39690 (11) | 0.0315 (7) | |
H3A | 0.0243 | 0.8620 | 0.4053 | 0.047* | 0.50 |
H3B | 0.1081 | 0.6995 | 0.4134 | 0.047* | 0.50 |
H3C | −0.1323 | 0.7293 | 0.4119 | 0.047* | 0.50 |
C4 | 0.0000 | 0.6329 (3) | 0.25212 (10) | 0.0194 (6) | |
C5 | 0.0000 | 0.6018 (3) | 0.30665 (10) | 0.0200 (6) | |
C6 | 0.0000 | 0.4508 (3) | 0.32377 (10) | 0.0210 (6) | |
C7 | 0.0000 | 0.3346 (3) | 0.27671 (10) | 0.0202 (6) | |
C8 | 0.0000 | 0.3812 (3) | 0.21762 (10) | 0.0189 (6) | |
C9 | 0.0000 | 0.5325 (3) | 0.20633 (10) | 0.0184 (6) | |
C10 | 0.0000 | 0.5814 (3) | 0.15243 (10) | 0.0221 (6) | |
H10 | 0.0000 | 0.6830 | 0.1448 | 0.026* | |
C11 | 0.0000 | 0.4819 (3) | 0.10997 (10) | 0.0243 (6) | |
H11 | 0.0000 | 0.5166 | 0.0732 | 0.029* | |
C12 | 0.0000 | 0.3313 (3) | 0.11940 (10) | 0.0221 (6) | |
C13 | 0.0000 | 0.2793 (3) | 0.17363 (10) | 0.0195 (6) | |
C14 | 0.0000 | 0.1179 (3) | 0.18488 (11) | 0.0353 (8) | |
H14A | −0.1365 | 0.0861 | 0.1926 | 0.042* | 0.50 |
H14B | 0.0825 | 0.0981 | 0.2166 | 0.042* | 0.50 |
C15 | 0.0843 (7) | 0.0305 (4) | 0.13403 (15) | 0.0428 (12) | 0.50 |
H15A | 0.0783 | −0.0727 | 0.1404 | 0.051* | 0.50 |
H15B | 0.2232 | 0.0575 | 0.1268 | 0.051* | 0.50 |
C16 | −0.0492 (11) | 0.0744 (4) | 0.08622 (15) | 0.049 (3) | 0.50 |
H16A | −0.1896 | 0.0678 | 0.0971 | 0.059* | 0.50 |
H16B | −0.0278 | 0.0091 | 0.0559 | 0.059* | 0.50 |
C17 | 0.0000 | 0.2317 (3) | 0.06866 (11) | 0.0294 (7) | |
C18 | 0.1883 (4) | 0.2607 (3) | 0.03377 (9) | 0.0509 (7) | |
H18A | 0.1895 | 0.1939 | 0.0023 | 0.076* | |
H18B | 0.3110 | 0.2451 | 0.0560 | 0.076* | |
H18C | 0.1856 | 0.3616 | 0.0205 | 0.076* | |
O1 | 0.0000 | 0.77918 (18) | 0.24416 (7) | 0.0236 (5) | |
O2 | 0.0000 | 0.4085 (2) | 0.37113 (7) | 0.0291 (5) | |
O3 | 0.0000 | 0.2080 (2) | 0.29159 (7) | 0.0293 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0282 (15) | 0.0191 (13) | 0.0275 (14) | 0.000 | 0.000 | −0.0064 (11) |
C2 | 0.0228 (14) | 0.0236 (13) | 0.0257 (13) | 0.000 | 0.000 | −0.0040 (11) |
C3 | 0.0406 (18) | 0.0298 (15) | 0.0241 (14) | 0.000 | 0.000 | −0.0053 (12) |
C4 | 0.0178 (13) | 0.0180 (12) | 0.0224 (13) | 0.000 | 0.000 | 0.0002 (10) |
C5 | 0.0171 (13) | 0.0208 (14) | 0.0220 (13) | 0.000 | 0.000 | −0.0002 (10) |
C6 | 0.0180 (13) | 0.0215 (13) | 0.0235 (13) | 0.000 | 0.000 | −0.0014 (10) |
C7 | 0.0162 (13) | 0.0202 (14) | 0.0240 (13) | 0.000 | 0.000 | 0.0018 (11) |
C8 | 0.0165 (13) | 0.0189 (12) | 0.0215 (13) | 0.000 | 0.000 | 0.0013 (10) |
C9 | 0.0146 (12) | 0.0209 (13) | 0.0198 (13) | 0.000 | 0.000 | −0.0010 (10) |
C10 | 0.0226 (14) | 0.0214 (13) | 0.0222 (13) | 0.000 | 0.000 | 0.0030 (11) |
C11 | 0.0290 (15) | 0.0244 (14) | 0.0195 (12) | 0.000 | 0.000 | 0.0008 (10) |
C12 | 0.0219 (14) | 0.0233 (13) | 0.0212 (13) | 0.000 | 0.000 | −0.0028 (11) |
C13 | 0.0177 (13) | 0.0181 (13) | 0.0228 (13) | 0.000 | 0.000 | −0.0011 (10) |
C14 | 0.061 (2) | 0.0192 (14) | 0.0254 (14) | 0.000 | 0.000 | −0.0005 (11) |
C15 | 0.076 (3) | 0.0224 (19) | 0.030 (2) | 0.0069 (19) | 0.001 (2) | −0.0050 (16) |
C16 | 0.091 (9) | 0.0283 (18) | 0.0280 (18) | −0.015 (3) | −0.002 (2) | −0.0086 (15) |
C17 | 0.0432 (18) | 0.0248 (14) | 0.0202 (13) | 0.000 | 0.000 | −0.0055 (11) |
C18 | 0.0437 (14) | 0.0737 (17) | 0.0352 (12) | −0.0013 (13) | 0.0074 (10) | −0.0271 (12) |
O1 | 0.0293 (11) | 0.0185 (9) | 0.0231 (9) | 0.000 | 0.000 | −0.0011 (7) |
O2 | 0.0401 (12) | 0.0273 (11) | 0.0200 (9) | 0.000 | 0.000 | 0.0029 (8) |
O3 | 0.0413 (12) | 0.0201 (10) | 0.0266 (10) | 0.000 | 0.000 | 0.0026 (8) |
C1—C2 | 1.354 (4) | C12—C13 | 1.403 (3) |
C1—O1 | 1.384 (3) | C12—C17 | 1.535 (3) |
C1—H1 | 0.9500 | C13—C14 | 1.504 (4) |
C2—C5 | 1.435 (4) | C14—C15i | 1.574 (4) |
C2—C3 | 1.496 (4) | C14—C15 | 1.575 (4) |
C3—H3A | 0.9800 | C14—H14A | 0.9600 |
C3—H3B | 0.9800 | C14—H14B | 0.9602 |
C3—H3C | 0.9800 | C15—C15i | 1.106 (10) |
C4—O1 | 1.355 (3) | C15—C16i | 1.252 (5) |
C4—C5 | 1.357 (3) | C15—C16 | 1.511 (6) |
C4—C9 | 1.445 (3) | C15—H15A | 0.9601 |
C5—C6 | 1.445 (3) | C15—H15B | 0.9600 |
C6—O2 | 1.216 (3) | C16—C16i | 0.646 (15) |
C6—C7 | 1.564 (3) | C16—C15i | 1.252 (5) |
C7—O3 | 1.216 (3) | C16—C17 | 1.539 (5) |
C7—C8 | 1.500 (3) | C16—H16A | 0.9600 |
C8—C9 | 1.414 (3) | C16—H16B | 0.9600 |
C8—C13 | 1.421 (4) | C17—C18 | 1.522 (3) |
C9—C10 | 1.386 (3) | C17—C18i | 1.522 (3) |
C10—C11 | 1.378 (4) | C17—C16i | 1.539 (5) |
C10—H10 | 0.9500 | C18—H18A | 0.9800 |
C11—C12 | 1.399 (4) | C18—H18B | 0.9800 |
C11—H11 | 0.9500 | C18—H18C | 0.9800 |
C2—C1—O1 | 111.7 (2) | C15—C14—H14B | 109.7 |
C2—C1—H1 | 124.2 | H14A—C14—H14B | 108.1 |
O1—C1—H1 | 124.2 | C15i—C15—C16i | 79.4 (4) |
C1—C2—C5 | 104.5 (2) | C15i—C15—C16 | 54.6 (3) |
C1—C2—C3 | 128.2 (2) | C16i—C15—C16 | 24.9 (6) |
C5—C2—C3 | 127.3 (2) | C15i—C15—C14 | 69.43 (17) |
C2—C3—H3A | 109.5 | C16i—C15—C14 | 120.1 (4) |
C2—C3—H3B | 109.5 | C16—C15—C14 | 105.4 (3) |
H3A—C3—H3B | 109.5 | C15i—C15—H15A | 87.7 |
C2—C3—H3C | 109.5 | C16i—C15—H15A | 117.4 |
H3A—C3—H3C | 109.5 | C16—C15—H15A | 111.3 |
H3B—C3—H3C | 109.5 | C14—C15—H15A | 111.1 |
O1—C4—C5 | 110.3 (2) | C15i—C15—H15B | 161.6 |
O1—C4—C9 | 121.4 (2) | C16i—C15—H15B | 85.5 |
C5—C4—C9 | 128.3 (2) | C16—C15—H15B | 109.9 |
C4—C5—C2 | 107.6 (2) | C14—C15—H15B | 110.3 |
C4—C5—C6 | 118.9 (2) | H15A—C15—H15B | 108.8 |
C2—C5—C6 | 133.5 (2) | C16i—C16—C15i | 100.6 (4) |
O2—C6—C5 | 125.3 (2) | C16i—C16—C15 | 54.6 (3) |
O2—C6—C7 | 118.5 (2) | C15i—C16—C15 | 46.0 (4) |
C5—C6—C7 | 116.2 (2) | C16i—C16—C17 | 77.9 (3) |
O3—C7—C8 | 123.9 (2) | C15i—C16—C17 | 126.7 (3) |
O3—C7—C6 | 115.6 (2) | C15—C16—C17 | 110.0 (4) |
C8—C7—C6 | 120.5 (2) | C16i—C16—H16A | 163.5 |
C9—C8—C13 | 119.9 (2) | C15i—C16—H16A | 63.0 |
C9—C8—C7 | 117.8 (2) | C15—C16—H16A | 109.1 |
C13—C8—C7 | 122.3 (2) | C17—C16—H16A | 109.7 |
C10—C9—C8 | 120.1 (2) | C16i—C16—H16B | 81.6 |
C10—C9—C4 | 121.5 (2) | C15i—C16—H16B | 122.7 |
C8—C9—C4 | 118.4 (2) | C15—C16—H16B | 109.9 |
C11—C10—C9 | 119.7 (2) | C17—C16—H16B | 109.9 |
C11—C10—H10 | 120.2 | H16A—C16—H16B | 108.3 |
C9—C10—H10 | 120.2 | C18—C17—C18i | 108.5 (3) |
C10—C11—C12 | 122.0 (2) | C18—C17—C12 | 110.17 (15) |
C10—C11—H11 | 119.0 | C18i—C17—C12 | 110.17 (15) |
C12—C11—H11 | 119.0 | C18—C17—C16i | 98.5 (3) |
C11—C12—C13 | 119.3 (2) | C18i—C17—C16i | 119.2 (3) |
C11—C12—C17 | 117.1 (2) | C12—C17—C16i | 109.5 (2) |
C13—C12—C17 | 123.6 (2) | C18—C17—C16 | 119.2 (3) |
C12—C13—C8 | 119.0 (2) | C18i—C17—C16 | 98.5 (3) |
C12—C13—C14 | 120.4 (2) | C12—C17—C16 | 109.5 (2) |
C8—C13—C14 | 120.6 (2) | C16i—C17—C16 | 24.2 (5) |
C13—C14—C15i | 111.0 (2) | C17—C18—H18A | 109.5 |
C13—C14—C15 | 111.0 (2) | C17—C18—H18B | 109.5 |
C15i—C14—C15 | 41.1 (3) | H18A—C18—H18B | 109.5 |
C13—C14—H14A | 109.5 | C17—C18—H18C | 109.5 |
C15i—C14—H14A | 70.8 | H18A—C18—H18C | 109.5 |
C15—C14—H14A | 109.1 | H18B—C18—H18C | 109.5 |
C13—C14—H14B | 109.4 | C4—O1—C1 | 105.86 (19) |
C15i—C14—H14B | 137.2 | ||
O1—C1—C2—C5 | 0.0 | C9—C8—C13—C14 | 180.0 |
O1—C1—C2—C3 | 180.000 (1) | C7—C8—C13—C14 | 0.0 |
O1—C4—C5—C2 | 0.0 | C12—C13—C14—C15i | −22.10 (19) |
C9—C4—C5—C2 | 180.0 | C8—C13—C14—C15i | 157.90 (19) |
O1—C4—C5—C6 | 180.0 | C12—C13—C14—C15 | 22.10 (19) |
C9—C4—C5—C6 | 0.000 (1) | C8—C13—C14—C15 | −157.90 (19) |
C1—C2—C5—C4 | 0.0 | C13—C14—C15—C15i | −98.27 (12) |
C3—C2—C5—C4 | 180.0 | C13—C14—C15—C16i | −34.7 (6) |
C1—C2—C5—C6 | 180.000 (1) | C15i—C14—C15—C16i | 63.6 (5) |
C3—C2—C5—C6 | 0.000 (1) | C13—C14—C15—C16 | −56.5 (4) |
C4—C5—C6—O2 | 180.0 | C15i—C14—C15—C16 | 41.8 (4) |
C2—C5—C6—O2 | 0.000 (1) | C15i—C15—C16—C16i | 179.998 (2) |
C4—C5—C6—C7 | 0.0 | C14—C15—C16—C16i | 130.1 (3) |
C2—C5—C6—C7 | 180.0 | C16i—C15—C16—C15i | 180.002 (1) |
O2—C6—C7—O3 | 0.0 | C14—C15—C16—C15i | −49.9 (3) |
C5—C6—C7—O3 | 180.0 | C15i—C15—C16—C17 | 122.2 (4) |
O2—C6—C7—C8 | 180.0 | C16i—C15—C16—C17 | −57.8 (4) |
C5—C6—C7—C8 | 0.0 | C14—C15—C16—C17 | 72.2 (4) |
O3—C7—C8—C9 | 180.0 | C11—C12—C17—C18 | 59.82 (17) |
C6—C7—C8—C9 | 0.0 | C13—C12—C17—C18 | −120.18 (17) |
O3—C7—C8—C13 | 0.0 | C11—C12—C17—C18i | −59.82 (17) |
C6—C7—C8—C13 | 180.0 | C13—C12—C17—C18i | 120.18 (17) |
C13—C8—C9—C10 | 0.0 | C11—C12—C17—C16i | 167.1 (3) |
C7—C8—C9—C10 | 180.0 | C13—C12—C17—C16i | −12.9 (3) |
C13—C8—C9—C4 | 180.0 | C11—C12—C17—C16 | −167.1 (3) |
C7—C8—C9—C4 | 0.0 | C13—C12—C17—C16 | 12.9 (3) |
O1—C4—C9—C10 | 0.0 | C16i—C16—C17—C18 | 33.80 (18) |
C5—C4—C9—C10 | 180.0 | C15i—C16—C17—C18 | 128.1 (6) |
O1—C4—C9—C8 | 180.0 | C15—C16—C17—C18 | 78.6 (4) |
C5—C4—C9—C8 | 0.0 | C16i—C16—C17—C18i | 150.60 (15) |
C8—C9—C10—C11 | 0.0 | C15i—C16—C17—C18i | −115.1 (7) |
C4—C9—C10—C11 | 180.0 | C15—C16—C17—C18i | −164.6 (3) |
C9—C10—C11—C12 | 0.0 | C16i—C16—C17—C12 | −94.37 (11) |
C10—C11—C12—C13 | 0.0 | C15i—C16—C17—C12 | −0.1 (8) |
C10—C11—C12—C17 | 180.0 | C15—C16—C17—C12 | −49.5 (4) |
C11—C12—C13—C8 | 0.0 | C15i—C16—C17—C16i | 94.3 (7) |
C17—C12—C13—C8 | 180.0 | C15—C16—C17—C16i | 44.8 (4) |
C11—C12—C13—C14 | 180.0 | C5—C4—O1—C1 | 0.0 |
C17—C12—C13—C14 | 0.0 | C9—C4—O1—C1 | 180.0 |
C9—C8—C13—C12 | 0.0 | C2—C1—O1—C4 | 0.0 |
C7—C8—C13—C12 | 180.0 |
Symmetry code: (i) −x, y, z. |
Experimental details
Crystal data | |
Chemical formula | C19H18O3 |
Mr | 294.33 |
Crystal system, space group | Orthorhombic, Pmna |
Temperature (K) | 113 |
a, b, c (Å) | 6.5579 (11), 9.1687 (15), 24.328 (4) |
V (Å3) | 1462.8 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.24 × 0.20 × 0.10 |
Data collection | |
Diffractometer | Rigaku Saturn |
Absorption correction | Multi-scan (SADABS; Sheldrick,1996) |
Tmin, Tmax | 0.968, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10602, 1404, 1343 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.057, 0.139, 1.17 |
No. of reflections | 1404 |
No. of parameters | 139 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.22 |
Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1997), SHELXTL.
Tanshinone IIA is one of the major active constitutes isolated from the traditional Chinese medicinal herb, Salvia miltiorrhiza Bunge, which has been widely used in China to treat coronary heart diseases (Chang et al., 1991), antitumour (Ryu et al., 1997), angina pectoris and myocardial infarction (Xue et al., 1999). Tanshinone IIA is also most effective and has been used as a qualitycontroller for some medicine. We report here the crystal structure (I)(Fig. 1).
The crystal structure of (I) illustrated in Fig. 1 shows that the C12—C17 ring has a twisted conformation. Also, the C4—C9 are essentially coplanar with the aromatic rings. An intermolecular C—H···O hydrogen bond links the molecules into a chain extending along the b axis. No π-π interactions are observed.