organic compounds
Brusatol
aGuangdong Province Key Laboratory of Pharmacodynamic Constituents of, Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China
*Correspondence e-mail: trwjiang@jnu.edu.cn
The title compound, C26H32O11, is composed of an α,β-unsaturated cyclohexanone ring (A), two cyclohexane rings (B and C), a six-membered lactone ring (D) and tetrahydrofuran ring (E). Ring A exists in a half-chair conformation with a C atom displaced by 0.679 (2) Å from the mean plane through the remaining five atoms. Ring B exists in a normal chair conformation. Both rings C and D exist in a twisted-chair conformation due to the O-atom bridge and the carbonyl group in rings C and D, respectively. Ring E shows an with a C atom displaced by 0.761 (1) Å from the mean plane through the remaining five atoms. The ring junctions are A/B trans, B/C trans, C/D cis and D/E cis. An intramolecular O—H⋯O hydrogen bond occurs. In the crystal, O—H⋯O hydrogen bonds involving the hydroxy, lactone and ester groups and C—H⋯O interactions are observed.
Related literature
For the isolation of brusatol, see: Sim et al. (1968); Kim et al. (2004). For its anticancer activity, see: Zhao et al. (2011) and for its antiviral activity, see: Yan et al. (2010). For the enhancement of the efficacy for chemotherapy, see: Ren et al. (2011). For the of bruceine A, see: Feng et al. 2010. For the of simalikalactone D, see: Moher et al. (1992).
Experimental
Crystal data
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Data collection: CrysAlis PRO (Agilent, 2011); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: XP in SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536812018582/vm2168sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812018582/vm2168Isup2.hkl
Dried seeds of brucea javanica (10 kg) were milled and extracted with 95% ethanol at room temperature and the extracted solution were concentrated to afford a syrup. The crude syrup was suspended in distilled water and partitioned with petroleum ether, ethyl acetate and n-butanol, successively. The ethyl acetate extract (82 g) was dissolved in warm methanol. After cooling, the raw brusatol precipitated as white powder. Then the powder (100 mg) was subjected to reverse phase HPLC to afford pure brusatol (83 mg). Colorless needles of the title compound were crystallized directly from the HPLC
acetonitrile: water 45:55.The C-bound H atoms were positioned geometrically and were included in the
in the riding-model approximation, with C—H = 0.96 Å (CH3) and Uiso(H) = 1.5Ueq(C); 0.97 Å (CH2) and Uiso(H) = 1.2Ueq(C); 0.98 Å (CH) and Uiso(H) = 1.2Ueq(C); O—H = 0.82 Å and Uiso(H) = 1.5Ueq(O). The can be unambiguously assigned with reference to the known configuration of the closed related compound simalikalactone D. The was refined to -0.07 (19).Data collection: CrysAlis PRO (Agilent, 2011); cell
CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C26H32O11 | Dx = 1.448 Mg m−3 |
Mr = 520.52 | Cu Kα radiation, λ = 1.54184 Å |
Orthorhombic, P212121 | Cell parameters from 2860 reflections |
a = 6.7162 (1) Å | θ = 3.2–62.6° |
b = 13.6796 (2) Å | µ = 0.96 mm−1 |
c = 25.9859 (5) Å | T = 288 K |
V = 2387.45 (7) Å3 | Needle, colourless |
Z = 4 | 0.44 × 0.15 × 0.11 mm |
F(000) = 1104 |
Oxford Gemini S Ultra Sapphire CCD diffractometer | 3380 independent reflections |
Radiation source: fine-focus sealed tube | 3182 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.020 |
ω scan | θmax = 62.6°, θmin = 3.2° |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | h = −7→6 |
Tmin = 0.748, Tmax = 1.000 | k = −13→15 |
4961 measured reflections | l = −29→29 |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.032 | w = 1/[σ2(Fo2) + (0.0463P)2 + 0.5393P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.085 | (Δ/σ)max = 0.001 |
S = 1.03 | Δρmax = 0.27 e Å−3 |
3380 reflections | Δρmin = −0.18 e Å−3 |
338 parameters | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0070 (4) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 1167 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.07 (19) |
C26H32O11 | V = 2387.45 (7) Å3 |
Mr = 520.52 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 6.7162 (1) Å | µ = 0.96 mm−1 |
b = 13.6796 (2) Å | T = 288 K |
c = 25.9859 (5) Å | 0.44 × 0.15 × 0.11 mm |
Oxford Gemini S Ultra Sapphire CCD diffractometer | 3380 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | 3182 reflections with I > 2σ(I) |
Tmin = 0.748, Tmax = 1.000 | Rint = 0.020 |
4961 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | H-atom parameters constrained |
wR(F2) = 0.085 | Δρmax = 0.27 e Å−3 |
S = 1.03 | Δρmin = −0.18 e Å−3 |
3380 reflections | Absolute structure: Flack (1983), 1167 Friedel pairs |
338 parameters | Absolute structure parameter: −0.07 (19) |
0 restraints |
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 | 0.6704 (3) | 0.54720 (14) | 0.02225 (7) | 0.0561 (6) | |
O2 | 0.7863 (3) | 0.37039 (16) | −0.00367 (7) | 0.0551 (5) | |
H2A | 0.7975 | 0.4234 | −0.0181 | 0.094 (15)* | |
O3 | 0.0404 (3) | 0.54519 (13) | 0.14364 (6) | 0.0441 (5) | |
H3A | −0.0296 | 0.5919 | 0.1516 | 0.080 (12)* | |
O4 | 0.2361 (3) | 0.56662 (12) | 0.27424 (6) | 0.0411 (4) | |
H4A | 0.2887 | 0.6182 | 0.2656 | 0.069 (11)* | |
O5 | −0.2473 (3) | 0.51540 (14) | 0.30530 (8) | 0.0653 (6) | |
O6 | −0.0670 (2) | 0.39701 (16) | 0.34093 (6) | 0.0505 (5) | |
O7 | −0.1327 (2) | 0.40828 (12) | 0.21639 (6) | 0.0342 (4) | |
O8 | 0.4711 (2) | 0.23809 (11) | 0.21922 (6) | 0.0349 (4) | |
O9 | 0.6417 (3) | 0.25571 (13) | 0.28957 (6) | 0.0424 (4) | |
O10 | 0.3429 (2) | 0.35608 (10) | 0.33806 (5) | 0.0281 (3) | |
O11 | 0.2397 (3) | 0.20076 (11) | 0.33187 (6) | 0.0389 (4) | |
C1 | 0.5140 (4) | 0.50092 (16) | 0.10202 (8) | 0.0332 (5) | |
H1A | 0.4364 | 0.5605 | 0.0990 | 0.040* | |
H1B | 0.6112 | 0.5104 | 0.1292 | 0.040* | |
C2 | 0.6203 (4) | 0.48223 (18) | 0.05223 (9) | 0.0377 (6) | |
C3 | 0.6762 (4) | 0.38148 (18) | 0.04044 (9) | 0.0370 (6) | |
C4 | 0.6333 (4) | 0.30630 (17) | 0.07122 (8) | 0.0333 (5) | |
C5 | 0.5044 (3) | 0.32145 (15) | 0.11842 (8) | 0.0273 (5) | |
H5A | 0.5971 | 0.3306 | 0.1471 | 0.033* | |
C6 | 0.3745 (4) | 0.23359 (15) | 0.13322 (8) | 0.0311 (5) | |
H6A | 0.2654 | 0.2271 | 0.1090 | 0.037* | |
H6B | 0.4532 | 0.1742 | 0.1319 | 0.037* | |
C7 | 0.2931 (3) | 0.24785 (15) | 0.18675 (8) | 0.0276 (5) | |
H7A | 0.2018 | 0.1940 | 0.1946 | 0.033* | |
C8 | 0.1859 (3) | 0.34436 (15) | 0.19626 (8) | 0.0237 (5) | |
C9 | 0.2988 (3) | 0.43333 (15) | 0.17275 (8) | 0.0247 (5) | |
H9A | 0.4203 | 0.4388 | 0.1934 | 0.030* | |
C10 | 0.3752 (3) | 0.41578 (15) | 0.11664 (8) | 0.0256 (5) | |
C11 | 0.1883 (4) | 0.53042 (16) | 0.18209 (8) | 0.0309 (5) | |
H11A | 0.2859 | 0.5833 | 0.1788 | 0.037* | |
C12 | 0.0966 (3) | 0.53777 (15) | 0.23619 (8) | 0.0293 (5) | |
H12A | −0.0104 | 0.5864 | 0.2352 | 0.035* | |
C13 | 0.0083 (3) | 0.44045 (16) | 0.25471 (8) | 0.0293 (5) | |
C14 | 0.1578 (3) | 0.35654 (15) | 0.25474 (8) | 0.0236 (4) | |
H14A | 0.0874 | 0.2983 | 0.2671 | 0.028* | |
C15 | 0.3574 (3) | 0.35998 (15) | 0.28264 (7) | 0.0250 (4) | |
H15A | 0.4201 | 0.4225 | 0.2738 | 0.030* | |
C16 | 0.4981 (4) | 0.27969 (16) | 0.26507 (8) | 0.0299 (5) | |
C18 | 0.7205 (4) | 0.2074 (2) | 0.06165 (10) | 0.0464 (7) | |
H18A | 0.7984 | 0.2089 | 0.0307 | 0.070* | |
H18B | 0.6152 | 0.1605 | 0.0580 | 0.070* | |
H18C | 0.8038 | 0.1893 | 0.0901 | 0.070* | |
C19 | 0.2138 (4) | 0.40703 (18) | 0.07452 (8) | 0.0340 (5) | |
H19A | 0.2763 | 0.3965 | 0.0418 | 0.051* | |
H19B | 0.1371 | 0.4662 | 0.0734 | 0.051* | |
H19C | 0.1278 | 0.3530 | 0.0823 | 0.051* | |
C20 | −0.0349 (3) | 0.34250 (16) | 0.18165 (8) | 0.0302 (5) | |
H20A | −0.0530 | 0.3637 | 0.1463 | 0.036* | |
H20B | −0.0884 | 0.2770 | 0.1852 | 0.036* | |
C21 | −0.1136 (4) | 0.45655 (17) | 0.30335 (9) | 0.0355 (6) | |
C22 | −0.1880 (5) | 0.4031 (3) | 0.38682 (10) | 0.0779 (11) | |
H22A | −0.1412 | 0.3565 | 0.4117 | 0.117* | |
H22B | −0.3240 | 0.3889 | 0.3783 | 0.117* | |
H22C | −0.1790 | 0.4677 | 0.4010 | 0.117* | |
C1' | 0.2828 (3) | 0.27079 (16) | 0.35871 (8) | 0.0308 (5) | |
C2' | 0.2793 (4) | 0.26745 (17) | 0.41472 (8) | 0.0365 (6) | |
H2'A | 0.2646 | 0.2051 | 0.4284 | 0.044* | |
C3' | 0.2934 (4) | 0.33837 (18) | 0.44969 (9) | 0.0384 (6) | |
C4' | 0.3105 (5) | 0.44546 (19) | 0.43916 (10) | 0.0527 (7) | |
H4'A | 0.3144 | 0.4562 | 0.4027 | 0.079* | |
H4'B | 0.4305 | 0.4701 | 0.4545 | 0.079* | |
H4'C | 0.1977 | 0.4788 | 0.4536 | 0.079* | |
C5' | 0.2881 (5) | 0.3129 (2) | 0.50613 (9) | 0.0623 (9) | |
H5'A | 0.2802 | 0.2432 | 0.5100 | 0.093* | |
H5'B | 0.1739 | 0.3427 | 0.5218 | 0.093* | |
H5'C | 0.4070 | 0.3365 | 0.5225 | 0.093* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0727 (14) | 0.0511 (11) | 0.0444 (10) | −0.0068 (11) | 0.0227 (11) | 0.0081 (9) |
O2 | 0.0584 (12) | 0.0674 (13) | 0.0396 (10) | −0.0005 (11) | 0.0244 (9) | −0.0064 (10) |
O3 | 0.0530 (11) | 0.0436 (10) | 0.0356 (9) | 0.0246 (9) | −0.0004 (8) | 0.0049 (7) |
O4 | 0.0518 (10) | 0.0336 (9) | 0.0378 (9) | −0.0135 (9) | 0.0035 (8) | −0.0034 (7) |
O5 | 0.0682 (14) | 0.0472 (11) | 0.0805 (14) | 0.0163 (11) | 0.0418 (12) | 0.0069 (10) |
O6 | 0.0322 (9) | 0.0896 (14) | 0.0296 (8) | 0.0093 (10) | 0.0090 (8) | 0.0096 (9) |
O7 | 0.0231 (7) | 0.0424 (9) | 0.0372 (8) | 0.0033 (7) | −0.0018 (7) | −0.0045 (7) |
O8 | 0.0376 (9) | 0.0365 (8) | 0.0308 (8) | 0.0146 (8) | −0.0027 (8) | −0.0025 (7) |
O9 | 0.0359 (9) | 0.0523 (10) | 0.0388 (9) | 0.0117 (8) | −0.0061 (8) | 0.0073 (8) |
O10 | 0.0336 (8) | 0.0287 (8) | 0.0219 (7) | −0.0042 (7) | −0.0026 (7) | 0.0022 (6) |
O11 | 0.0555 (11) | 0.0297 (8) | 0.0314 (8) | −0.0101 (8) | −0.0033 (8) | −0.0006 (7) |
C1 | 0.0356 (12) | 0.0338 (12) | 0.0301 (11) | −0.0011 (11) | 0.0055 (10) | −0.0005 (9) |
C2 | 0.0378 (13) | 0.0440 (14) | 0.0311 (12) | −0.0058 (12) | 0.0058 (11) | 0.0008 (11) |
C3 | 0.0319 (12) | 0.0496 (15) | 0.0295 (11) | 0.0001 (11) | 0.0092 (10) | −0.0069 (11) |
C4 | 0.0285 (11) | 0.0406 (13) | 0.0307 (11) | 0.0020 (11) | −0.0014 (11) | −0.0105 (11) |
C5 | 0.0256 (11) | 0.0306 (11) | 0.0259 (10) | 0.0027 (10) | −0.0019 (10) | −0.0041 (9) |
C6 | 0.0355 (12) | 0.0257 (11) | 0.0321 (11) | 0.0020 (11) | 0.0011 (11) | −0.0056 (9) |
C7 | 0.0275 (11) | 0.0249 (10) | 0.0303 (11) | −0.0003 (9) | −0.0016 (10) | −0.0014 (9) |
C8 | 0.0234 (11) | 0.0241 (11) | 0.0235 (10) | −0.0005 (9) | 0.0000 (9) | −0.0037 (8) |
C9 | 0.0257 (10) | 0.0254 (10) | 0.0230 (10) | −0.0007 (9) | −0.0004 (9) | −0.0014 (8) |
C10 | 0.0239 (10) | 0.0283 (11) | 0.0248 (11) | 0.0021 (10) | 0.0012 (9) | −0.0004 (9) |
C11 | 0.0362 (12) | 0.0241 (10) | 0.0323 (11) | 0.0037 (10) | 0.0055 (10) | 0.0037 (9) |
C12 | 0.0328 (12) | 0.0235 (11) | 0.0316 (11) | 0.0052 (10) | 0.0058 (10) | 0.0007 (9) |
C13 | 0.0266 (10) | 0.0305 (12) | 0.0307 (11) | −0.0006 (10) | 0.0038 (10) | −0.0009 (9) |
C14 | 0.0246 (10) | 0.0229 (10) | 0.0234 (10) | −0.0025 (9) | 0.0009 (9) | 0.0010 (8) |
C15 | 0.0271 (10) | 0.0270 (10) | 0.0209 (9) | −0.0019 (9) | −0.0010 (9) | 0.0042 (9) |
C16 | 0.0308 (12) | 0.0301 (12) | 0.0289 (11) | 0.0009 (10) | 0.0015 (10) | 0.0068 (9) |
C18 | 0.0416 (14) | 0.0490 (15) | 0.0487 (15) | 0.0056 (13) | 0.0082 (13) | −0.0169 (12) |
C19 | 0.0337 (12) | 0.0423 (13) | 0.0260 (11) | 0.0037 (12) | −0.0039 (10) | −0.0007 (10) |
C20 | 0.0257 (11) | 0.0352 (12) | 0.0299 (11) | −0.0013 (10) | −0.0024 (10) | −0.0015 (9) |
C21 | 0.0325 (12) | 0.0319 (12) | 0.0421 (13) | −0.0048 (11) | 0.0101 (11) | −0.0058 (11) |
C22 | 0.0446 (17) | 0.157 (4) | 0.0324 (15) | 0.009 (2) | 0.0143 (13) | 0.0076 (19) |
C1' | 0.0333 (12) | 0.0300 (12) | 0.0291 (11) | −0.0013 (11) | 0.0003 (10) | 0.0034 (10) |
C2' | 0.0463 (14) | 0.0349 (12) | 0.0284 (11) | 0.0027 (12) | −0.0004 (11) | 0.0069 (10) |
C3' | 0.0368 (13) | 0.0484 (14) | 0.0299 (12) | 0.0042 (12) | −0.0002 (11) | −0.0020 (11) |
C4' | 0.0618 (18) | 0.0455 (15) | 0.0508 (16) | −0.0112 (15) | 0.0082 (15) | −0.0182 (13) |
C5' | 0.081 (2) | 0.077 (2) | 0.0292 (13) | 0.019 (2) | −0.0019 (15) | −0.0030 (14) |
O1—C2 | 1.229 (3) | C9—C11 | 1.541 (3) |
O2—C3 | 1.372 (3) | C9—C10 | 1.564 (3) |
O2—H2A | 0.8200 | C9—H9A | 0.9800 |
O3—C11 | 1.423 (3) | C10—C19 | 1.545 (3) |
O3—H3A | 0.8200 | C11—C12 | 1.538 (3) |
O4—C12 | 1.418 (3) | C11—H11A | 0.9800 |
O4—H4A | 0.8200 | C12—C13 | 1.535 (3) |
O5—C21 | 1.207 (3) | C12—H12A | 0.9800 |
O6—C21 | 1.310 (3) | C13—C21 | 1.522 (3) |
O6—C22 | 1.445 (3) | C13—C14 | 1.525 (3) |
O7—C20 | 1.434 (3) | C14—C15 | 1.525 (3) |
O7—C13 | 1.443 (3) | C14—H14A | 0.9800 |
O8—C16 | 1.333 (3) | C15—C16 | 1.519 (3) |
O8—C7 | 1.469 (3) | C15—H15A | 0.9800 |
O9—C16 | 1.201 (3) | C18—H18A | 0.9600 |
O10—C1' | 1.346 (3) | C18—H18B | 0.9600 |
O10—C15 | 1.444 (2) | C18—H18C | 0.9600 |
O11—C1' | 1.220 (3) | C19—H19A | 0.9600 |
C1—C2 | 1.500 (3) | C19—H19B | 0.9600 |
C1—C10 | 1.539 (3) | C19—H19C | 0.9600 |
C1—H1A | 0.9700 | C20—H20A | 0.9700 |
C1—H1B | 0.9700 | C20—H20B | 0.9700 |
C2—C3 | 1.461 (3) | C22—H22A | 0.9600 |
C3—C4 | 1.334 (3) | C22—H22B | 0.9600 |
C4—C18 | 1.495 (3) | C22—H22C | 0.9600 |
C4—C5 | 1.516 (3) | C1'—C2' | 1.456 (3) |
C5—C6 | 1.534 (3) | C2'—C3' | 1.333 (3) |
C5—C10 | 1.556 (3) | C2'—H2'A | 0.9300 |
C5—H5A | 0.9800 | C3'—C4' | 1.495 (4) |
C6—C7 | 1.507 (3) | C3'—C5' | 1.508 (3) |
C6—H6A | 0.9700 | C4'—H4'A | 0.9600 |
C6—H6B | 0.9700 | C4'—H4'B | 0.9600 |
C7—C8 | 1.524 (3) | C4'—H4'C | 0.9600 |
C7—H7A | 0.9800 | C5'—H5'A | 0.9600 |
C8—C20 | 1.531 (3) | C5'—H5'B | 0.9600 |
C8—C14 | 1.540 (3) | C5'—H5'C | 0.9600 |
C8—C9 | 1.559 (3) | ||
C3—O2—H2A | 109.5 | O7—C13—C21 | 105.32 (18) |
C11—O3—H3A | 109.5 | O7—C13—C14 | 101.70 (16) |
C12—O4—H4A | 109.5 | C21—C13—C14 | 117.56 (19) |
C21—O6—C22 | 116.4 (2) | O7—C13—C12 | 107.57 (17) |
C20—O7—C13 | 108.99 (16) | C21—C13—C12 | 110.05 (18) |
C16—O8—C7 | 125.83 (17) | C14—C13—C12 | 113.48 (18) |
C1'—O10—C15 | 116.72 (16) | C15—C14—C13 | 123.77 (18) |
C2—C1—C10 | 111.86 (18) | C15—C14—C8 | 111.37 (17) |
C2—C1—H1A | 109.2 | C13—C14—C8 | 99.31 (16) |
C10—C1—H1A | 109.2 | C15—C14—H14A | 107.1 |
C2—C1—H1B | 109.2 | C13—C14—H14A | 107.1 |
C10—C1—H1B | 109.2 | C8—C14—H14A | 107.1 |
H1A—C1—H1B | 107.9 | O10—C15—C16 | 108.35 (16) |
O1—C2—C3 | 118.6 (2) | O10—C15—C14 | 114.43 (17) |
O1—C2—C1 | 123.6 (2) | C16—C15—C14 | 112.44 (17) |
C3—C2—C1 | 117.6 (2) | O10—C15—H15A | 107.1 |
C4—C3—O2 | 122.1 (2) | C16—C15—H15A | 107.1 |
C4—C3—C2 | 123.1 (2) | C14—C15—H15A | 107.1 |
O2—C3—C2 | 114.7 (2) | O9—C16—O8 | 117.8 (2) |
C3—C4—C18 | 120.9 (2) | O9—C16—C15 | 122.5 (2) |
C3—C4—C5 | 120.2 (2) | O8—C16—C15 | 119.52 (18) |
C18—C4—C5 | 118.8 (2) | C4—C18—H18A | 109.5 |
C4—C5—C6 | 114.88 (17) | C4—C18—H18B | 109.5 |
C4—C5—C10 | 114.09 (17) | H18A—C18—H18B | 109.5 |
C6—C5—C10 | 109.88 (17) | C4—C18—H18C | 109.5 |
C4—C5—H5A | 105.7 | H18A—C18—H18C | 109.5 |
C6—C5—H5A | 105.7 | H18B—C18—H18C | 109.5 |
C10—C5—H5A | 105.7 | C10—C19—H19A | 109.5 |
C7—C6—C5 | 109.64 (17) | C10—C19—H19B | 109.5 |
C7—C6—H6A | 109.7 | H19A—C19—H19B | 109.5 |
C5—C6—H6A | 109.7 | C10—C19—H19C | 109.5 |
C7—C6—H6B | 109.7 | H19A—C19—H19C | 109.5 |
C5—C6—H6B | 109.7 | H19B—C19—H19C | 109.5 |
H6A—C6—H6B | 108.2 | O7—C20—C8 | 106.08 (17) |
O8—C7—C6 | 102.92 (17) | O7—C20—H20A | 110.5 |
O8—C7—C8 | 111.71 (16) | C8—C20—H20A | 110.5 |
C6—C7—C8 | 115.66 (18) | O7—C20—H20B | 110.5 |
O8—C7—H7A | 108.8 | C8—C20—H20B | 110.5 |
C6—C7—H7A | 108.8 | H20A—C20—H20B | 108.7 |
C8—C7—H7A | 108.8 | O5—C21—O6 | 124.2 (2) |
C7—C8—C20 | 113.77 (18) | O5—C21—C13 | 122.1 (2) |
C7—C8—C14 | 108.16 (17) | O6—C21—C13 | 113.6 (2) |
C20—C8—C14 | 97.32 (17) | O6—C22—H22A | 109.5 |
C7—C8—C9 | 112.53 (17) | O6—C22—H22B | 109.5 |
C20—C8—C9 | 112.77 (17) | H22A—C22—H22B | 109.5 |
C14—C8—C9 | 111.21 (16) | O6—C22—H22C | 109.5 |
C11—C9—C8 | 112.15 (17) | H22A—C22—H22C | 109.5 |
C11—C9—C10 | 115.92 (17) | H22B—C22—H22C | 109.5 |
C8—C9—C10 | 113.89 (16) | O11—C1'—O10 | 121.61 (19) |
C11—C9—H9A | 104.5 | O11—C1'—C2' | 122.9 (2) |
C8—C9—H9A | 104.5 | O10—C1'—C2' | 115.5 (2) |
C10—C9—H9A | 104.5 | C3'—C2'—C1' | 131.1 (2) |
C1—C10—C19 | 107.97 (17) | C3'—C2'—H2'A | 114.4 |
C1—C10—C5 | 107.28 (17) | C1'—C2'—H2'A | 114.4 |
C19—C10—C5 | 110.36 (17) | C2'—C3'—C4' | 126.4 (2) |
C1—C10—C9 | 108.21 (17) | C2'—C3'—C5' | 119.6 (2) |
C19—C10—C9 | 116.26 (18) | C4'—C3'—C5' | 114.0 (2) |
C5—C10—C9 | 106.41 (16) | C3'—C4'—H4'A | 109.5 |
O3—C11—C12 | 110.70 (18) | C3'—C4'—H4'B | 109.5 |
O3—C11—C9 | 110.37 (17) | H4'A—C4'—H4'B | 109.5 |
C12—C11—C9 | 113.15 (17) | C3'—C4'—H4'C | 109.5 |
O3—C11—H11A | 107.5 | H4'A—C4'—H4'C | 109.5 |
C12—C11—H11A | 107.5 | H4'B—C4'—H4'C | 109.5 |
C9—C11—H11A | 107.5 | C3'—C5'—H5'A | 109.5 |
O4—C12—C13 | 106.15 (17) | C3'—C5'—H5'B | 109.5 |
O4—C12—C11 | 113.04 (18) | H5'A—C5'—H5'B | 109.5 |
C13—C12—C11 | 112.62 (17) | C3'—C5'—H5'C | 109.5 |
O4—C12—H12A | 108.3 | H5'A—C5'—H5'C | 109.5 |
C13—C12—H12A | 108.3 | H5'B—C5'—H5'C | 109.5 |
C11—C12—H12A | 108.3 | ||
C10—C1—C2—O1 | 149.1 (2) | O3—C11—C12—C13 | 85.9 (2) |
C10—C1—C2—C3 | −34.3 (3) | C9—C11—C12—C13 | −38.6 (3) |
O1—C2—C3—C4 | 178.2 (2) | C20—O7—C13—C21 | −148.07 (18) |
C1—C2—C3—C4 | 1.5 (4) | C20—O7—C13—C14 | −24.9 (2) |
O1—C2—C3—O2 | 1.5 (4) | C20—O7—C13—C12 | 94.6 (2) |
C1—C2—C3—O2 | −175.2 (2) | O4—C12—C13—O7 | −179.23 (16) |
O2—C3—C4—C18 | 6.0 (4) | C11—C12—C13—O7 | −55.0 (2) |
C2—C3—C4—C18 | −170.5 (2) | O4—C12—C13—C21 | 66.5 (2) |
O2—C3—C4—C5 | −177.6 (2) | C11—C12—C13—C21 | −169.28 (19) |
C2—C3—C4—C5 | 6.0 (4) | O4—C12—C13—C14 | −67.5 (2) |
C3—C4—C5—C6 | 148.1 (2) | C11—C12—C13—C14 | 56.6 (2) |
C18—C4—C5—C6 | −35.4 (3) | O7—C13—C14—C15 | 170.06 (18) |
C3—C4—C5—C10 | 19.9 (3) | C21—C13—C14—C15 | −75.6 (3) |
C18—C4—C5—C10 | −163.6 (2) | C12—C13—C14—C15 | 54.8 (3) |
C4—C5—C6—C7 | 166.34 (18) | O7—C13—C14—C8 | 46.42 (19) |
C10—C5—C6—C7 | −63.4 (2) | C21—C13—C14—C8 | 160.78 (19) |
C16—O8—C7—C6 | 152.39 (19) | C12—C13—C14—C8 | −68.8 (2) |
C16—O8—C7—C8 | 27.7 (3) | C7—C8—C14—C15 | 61.3 (2) |
C5—C6—C7—O8 | −69.4 (2) | C20—C8—C14—C15 | 179.31 (17) |
C5—C6—C7—C8 | 52.7 (3) | C9—C8—C14—C15 | −62.8 (2) |
O8—C7—C8—C20 | −156.51 (17) | C7—C8—C14—C13 | −166.73 (17) |
C6—C7—C8—C20 | 86.2 (2) | C20—C8—C14—C13 | −48.70 (19) |
O8—C7—C8—C14 | −49.6 (2) | C9—C8—C14—C13 | 69.2 (2) |
C6—C7—C8—C14 | −166.86 (19) | C1'—O10—C15—C16 | −57.0 (2) |
O8—C7—C8—C9 | 73.7 (2) | C1'—O10—C15—C14 | 69.3 (2) |
C6—C7—C8—C9 | −43.6 (2) | C13—C14—C15—O10 | 71.0 (3) |
C7—C8—C9—C11 | 179.43 (18) | C8—C14—C15—O10 | −170.89 (16) |
C20—C8—C9—C11 | 49.1 (2) | C13—C14—C15—C16 | −164.80 (18) |
C14—C8—C9—C11 | −59.0 (2) | C8—C14—C15—C16 | −46.7 (2) |
C7—C8—C9—C10 | 45.3 (2) | C7—O8—C16—O9 | 171.5 (2) |
C20—C8—C9—C10 | −85.0 (2) | C7—O8—C16—C15 | −13.0 (3) |
C14—C8—C9—C10 | 166.82 (17) | O10—C15—C16—O9 | −35.3 (3) |
C2—C1—C10—C19 | −62.7 (2) | C14—C15—C16—O9 | −162.7 (2) |
C2—C1—C10—C5 | 56.3 (2) | O10—C15—C16—O8 | 149.45 (18) |
C2—C1—C10—C9 | 170.74 (19) | C14—C15—C16—O8 | 22.0 (3) |
C4—C5—C10—C1 | −49.7 (2) | C13—O7—C20—C8 | −6.9 (2) |
C6—C5—C10—C1 | 179.60 (17) | C7—C8—C20—O7 | 148.59 (17) |
C4—C5—C10—C19 | 67.7 (2) | C14—C8—C20—O7 | 35.0 (2) |
C6—C5—C10—C19 | −63.0 (2) | C9—C8—C20—O7 | −81.7 (2) |
C4—C5—C10—C9 | −165.37 (18) | C22—O6—C21—O5 | 0.9 (4) |
C6—C5—C10—C9 | 64.0 (2) | C22—O6—C21—C13 | −175.2 (2) |
C11—C9—C10—C1 | 57.6 (2) | O7—C13—C21—O5 | −61.0 (3) |
C8—C9—C10—C1 | −170.06 (18) | C14—C13—C21—O5 | −173.3 (2) |
C11—C9—C10—C19 | −64.1 (3) | C12—C13—C21—O5 | 54.7 (3) |
C8—C9—C10—C19 | 68.3 (2) | O7—C13—C21—O6 | 115.2 (2) |
C11—C9—C10—C5 | 172.60 (18) | C14—C13—C21—O6 | 2.8 (3) |
C8—C9—C10—C5 | −55.0 (2) | C12—C13—C21—O6 | −129.1 (2) |
C8—C9—C11—O3 | −84.4 (2) | C15—O10—C1'—O11 | −1.1 (3) |
C10—C9—C11—O3 | 48.7 (2) | C15—O10—C1'—C2' | 177.03 (19) |
C8—C9—C11—C12 | 40.2 (2) | O11—C1'—C2'—C3' | −169.2 (3) |
C10—C9—C11—C12 | 173.40 (18) | O10—C1'—C2'—C3' | 12.7 (4) |
O3—C11—C12—O4 | −153.84 (17) | C1'—C2'—C3'—C4' | 2.3 (5) |
C9—C11—C12—O4 | 81.7 (2) | C1'—C2'—C3'—C5' | −179.0 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2A···O1 | 0.82 | 2.17 | 2.629 (3) | 116 |
O3—H3A···O11i | 0.82 | 2.09 | 2.911 (2) | 173 |
O4—H4A···O9ii | 0.82 | 2.41 | 3.180 (2) | 157 |
O4—H4A···O8ii | 0.82 | 2.33 | 3.066 (2) | 149 |
C11—H11A···O9ii | 0.98 | 2.54 | 3.368 (4) | 142 |
C5′—H5′B···O1iii | 0.96 | 2.76 | 3.650 (3) | 155 |
Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1/2, −y+1, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C26H32O11 |
Mr | 520.52 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 288 |
a, b, c (Å) | 6.7162 (1), 13.6796 (2), 25.9859 (5) |
V (Å3) | 2387.45 (7) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.96 |
Crystal size (mm) | 0.44 × 0.15 × 0.11 |
Data collection | |
Diffractometer | Oxford Gemini S Ultra Sapphire CCD diffractometer |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2011) |
Tmin, Tmax | 0.748, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4961, 3380, 3182 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.576 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.085, 1.03 |
No. of reflections | 3380 |
No. of parameters | 338 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.18 |
Absolute structure | Flack (1983), 1167 Friedel pairs |
Absolute structure parameter | −0.07 (19) |
Computer programs: CrysAlis PRO (Agilent, 2011), XP in SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2A···O1 | 0.82 | 2.17 | 2.629 (3) | 115.7 |
O3—H3A···O11i | 0.82 | 2.09 | 2.911 (2) | 172.6 |
O4—H4A···O9ii | 0.82 | 2.41 | 3.180 (2) | 156.5 |
O4—H4A···O8ii | 0.82 | 2.33 | 3.066 (2) | 148.9 |
C11—H11A···O9ii | 0.98 | 2.54 | 3.368 (4) | 141.6 |
C5'—H5'B···O1iii | 0.96 | 2.76 | 3.650 (3) | 154.6 |
Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1/2, −y+1, z+1/2. |
Acknowledgements
This work was supported by grants from the New Century Excellent Talents Scheme of the Ministry of Education (NCET-08–0612), the National Science Foundation of China (21072078), the Guangdong High Level Talent Scheme and the Fundamental Research Funds for the Central Universities (21609202).
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The title compound brusatol is a natural product originally isolated from the seeds of Brucea sumatrana (Sim et al., 1968). It was also isolated from the chinese herbal medicine Brucea javanica (Kim et al., 2004). Brusatol was found to show potent anticancer activity (Zhao et al., 2011) and antiviral activity against the tobaccomosaic virus (Yan et al., 2010). Furthermore, it was reported that brusatol could effectively enhance the efficacy of chemotherapy by inhibiting the Nrf2-mediated defense mechanism (Ren et al., 2011). The crystal strcuture of bruceine A, an analogue of brusatol, was reported recently (Feng et al., 2010); however, no detailed structural information was provided. We report herein the three-dimensional structure of the title compound.
Brusatol consists of an α,β-unsaturated cyclohexanone ring (A), two cyclohexane rings (B and C), a six-membered lactone ring (D) and tetrahydrofuran ring (E). Ring A exists in a half chair conformation with C10 displaced by 0.679 (2) Å from the least squares plane through the remaining five atoms (C1, C2, C3, C4 and C5). Ring B exists in a normal chair conformation. Both rings C and D exist in a twisted chair conformation due to the oxygen bridge and carbonyl group in rings C and D, respectively. Ring E shows an envelop conformation with C14 displaced by 0.761 (1) Å from the least squares plane through the remaining four atoms (C8, C13, C20 and O7). The planes through rings A and E are roughly perpendicular to each other with a dihedral angle of 86.15 (9)°. There are two side chains at C13 and C15. The planes through the two ester groups in the side chains make a dihedral angle of 62.36 (10). The ring junctures are A/B trans, B/C trans, C/D cis and D/E cis. The absolute configuration determined for simalikalactone D (Moher et al., 1992), a similar quassinoid, was invoked, giving the assignments of the chiral centres in the molecule as shown in Fig. 1.
Intermolecular O–H···O hydrogen bonds (Table 1) between the hydroxyl groups at C11 and the ester group at C1' [O3···O11i = 2.911 (2) Å, symmetry code: (i) -x, 0.5 + y, 0.5 - z], between the hydroxyl group at C12 and the lactone group at C16 [O4···O8ii = 3.066 (2) Å and O4···O9ii = 3.180 (2) Å, symmetry code: (ii) 1 - x, 0.5 + y, 0.5 - z], and short C–H···O contacts between the methine group at C11 and the lactone group at C16 [C11···O9ii = 3.368 (4) Å] link adjacent molecules into chains along the b-axis. Adjacent chains are further linked by weak C–H···O interactions between the terminal methyl group and the ketone group at C2 [C5'···O1iii = 3.650 (3) Å, symmetry code: (iii) 0.5 - x, 1 - y, 0.5 + z] into a three-dimensional network (Fig. 2).