Literature DB >> 29250361

Crystal structure of ochraceolide A isolated from Elaeodendron trichotomum (Turcz.) Lundell.

Angel D Herrera-España1, Gonzalo J Mena-Rejón1, Simón Hernández-Ortega2, Leovigildo Quijano2, Gumersindo Mirón-López1.   

Abstract

The title compound, C30H44O3 [systematic name: 6aR,6 bR,8aS,9aR,12aR,14bR)-4,4,6a,6;b,8a,14b-hexa-methyl-12-methyl-eneicosa-hydro-3H-phenanthro[1',2':6,7]indeno-[2,1-b]furan-3,11(2H)-dione], is a triterpene lactone, which was isolated from di-chloro-methane extract of Elaeodendron trichotomum (Turcz.) Lundell (celastraceae) stem bark. The compound has a lupane skeleton and consists of four fused six-membered rings and two five-membered rings. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds into a three-dimensional network. The configuration of ochraceolide A was proposed based on analogue compounds which belong to the lupane type.

Entities:  

Keywords:  Elaeodendron trichotomum; crystal structure; ochraceolide A; triterpene lactone

Year:  2017        PMID: 29250361      PMCID: PMC5730298          DOI: 10.1107/S2056989017012816

Source DB:  PubMed          Journal:  Acta Crystallogr E Crystallogr Commun


Chemical context

Ochraceolides A–E are a group of cytotoxic lupane γ-lactones isolated from the Celastraceae family. Ochraceolide A was firstly isolated from Kokoona ochracea (Elm.) Merril stem bark (Ngassapa et al., 1991 ▸) and afterwards from Lophopetalum wallichii (Sturm et al., 1996 ▸) and Cassine xylocarpa (Callies et al., 2015 ▸). The title compound has shown significant cytotoxic activity against murine lymphocytic leukemia cells (P-388) with an ED50 of 0.6 µM; human oral epidermoid carcinoma (KB-3) with an ED50 of 6.0 µM; and hormone-dependent breast cancer with an ED50 of 9.9 µM (Ngassapa et al., 1991 ▸; Sturm et al., 1996 ▸). In the same way, this compound has exhibited significant inhibitory activity in the FPTase assay with an IC50 of 2.2 µM (Sturm et al., 1996 ▸) and inhibitory effects of human immunodeficiency virus type 1 replication with an IC50 of 39.0 µM (Callies et al., 2015 ▸). Ochraceolide A is part of the structure of the Diels–Alder adduct (i.e. celastroidine A or volubilide) isolated from Hippocratea celastroides K. (Jiménez-Estrada et al., 2000 ▸) and Hyppocratea volubilis L. (Alvarenga et al., 2000 ▸). In these publications, the crystal structure of the adduct was reported as a solvate of di­chloro­methane and toluene, respectively. The X-ray analysis showed that the Diels–Alder adduct was integrated by the triterpene ochraceolide A and a theoretical diterpene, in which the former seems to have acted as dienophile and the latter as diene in the biosynthesis. Herein the first isolation of ochraceolide A from Elaeodendron trichotomum (Turcz.) Lundell stem bark is reported and the crystal structure described.

Structural commentary

The title compound has a lupane skeleton and crystallizes in the ortho­rhom­bic space group P212121 with one mol­ecule in the asymmetric unit (Fig. 1 ▸). The triterpene skeleton consists of four fused six-membered rings (A–D) and two five-membered rings (E and F). The cyclo­hexane rings are trans-fused and in standard chair conformations. The cyclo­pentane (C17–C19/C21/C22) ring is trans-fused to the triterpene D ring and exhibits an envelope conformation [Q = 0.451 (4) Å and θ = 356.7 (5)°] with the puckered C17 atom having the maximum deviation of 0.285 (4) Å. The α-methyl­ene γ-lactone is cis-fused at C19–C21 to the cyclo­pentane E ring and is essentially planar with a maximum deviation of 0.006 (4) Å for atom C19. The torsion angle C20—C19—C21—O2 is 0.8 (4)° and the weighted average absolute inter­nal torsion angle for the lactone ring is 0.7 (2)°
Figure 1

The molecular structure of the title compound with the atom labelling. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radius.

Supra­molecular features

In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds (Table 1 ▸, Fig. 2 ▸). The lactone and A rings of adjacent mol­ecules inter­act through two hydrogen bonds (C2—H2A⋯O2 and C24—H24A⋯O3) in a head-to-tail arrangement, forming chains along [001]. These chains are further connected through a weak hydrogen bond between the oxygen of the ketone group (O1) and a methyl­ene group on the C ring (C12), forming an overall three-dimensional network.
Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A D—HH⋯A DA D—H⋯A
C2—H2A⋯O2i 0.992.573.395 (5)141
C12—H12A⋯O1ii 0.992.453.310 (6)146
C24—H24A⋯O3i 0.982.583.357 (6)137

Symmetry codes: (i) ; (ii) .

Figure 2

Part of the crystal structure showing hydrogen bonds as blue lines.

Database survey

A search of the Cambridge Structural Database (CSD Version 5.38, update November 2016; Groom et al., 2016 ▸) for α-methyl­ene γ-lactone fused to a cyclo­pentane ring gave only one entry for 6,6-dimethyl-3-methyl­ene­tetra­hydro-2H-cyclo­penta­[b]furan-2,5(3H)-dione (CCDC 658922; Edwards et al., 2008 ▸). In both compounds, the principal supra­molecular inter­actions are C—H⋯O hydrogen bonds and the α-methyl­ene γ-lactones are cis-fused to the corresponding cyclo­pentane ring. However, unlike the title compound, the γ-lactone of the synthetic compound presents a twisted conformation.

Isolation and crystallization

Elaeodendron trichotomum (Turcz.) Lundell was collected from Chunchucmil, Yucatán, México (20o 51.032′ N, 90o 11.488′ W). A voucher specimen (JTun2328) was deposited at the Herbarium Alfredo Barrera Marín, Universidad Autónoma de Yucatán, México. Dried and milled stem bark (2100 g) was exhaustively extracted by di­chloro­methane using a Soxhlet extraction apparatus to yield 184.2 g of crude extract. A portion of the extract (100 g) was chromatographed on silica gel (40–60 µm) using a gradient elution with n-hexa­ne–ethyl acetate (10–100% ethyl acetate), to obtain 44 fractions. Single crystals suitable for X-ray structure analysis were obtained by slow evaporation of the mixture of solvents present in fractions 7–10 at room temperature.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. Hydrogen atoms bonded to C atoms were positioned geometrically and refined using a riding model with C—H = 0.95–1.00 Å with U iso(H) = 1.2U eq(C) or 1.5U eq(methyl C).
Table 2

Experimental details

Crystal data
Chemical formulaC30H44O3
M r 452.65
Crystal system, space groupOrthorhombic, P212121
Temperature (K)150
a, b, c (Å)7.6131 (5), 11.7216 (7), 27.7076 (17)
V3)2472.6 (3)
Z 4
Radiation typeCu Kα
μ (mm−1)0.59
Crystal size (mm)0.36 × 0.27 × 0.25
 
Data collection
DiffractometerBruker D8 Venture
Absorption correctionMulti-scan (SADABS; Krause et al., 2015)
T min, T max 0.783, 0.864
No. of measured, independent and observed [I > 2σ(I)] reflections14632, 4513, 4057
R int 0.061
(sin θ/λ)max−1)0.603
 
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S 0.061, 0.164, 1.09
No. of reflections4513
No. of parameters304
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.28, −0.19
Absolute structureFlack x determined using 1515 quotients [(I +)−(I )]/[(I +)+(I )] (Parsons et al., 2013).
Absolute structure parameter0.2 (3)

Computer programs: APEX3 and SAINT (Bruker, 2014 ▸), SHELXS2014 (Bruker, 2014 ▸), SHELXL2014/7 (Sheldrick, 2015 ▸), Mercury (Macrae et al., 2006 ▸), PLATON (Spek, 2009 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989017012816/lh4023sup1.cif Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989017012816/lh4023Isup2.hkl CCDC reference: 1573017 Additional supporting information: crystallographic information; 3D view; checkCIF report
C30H44O3Dx = 1.216 Mg m3
Mr = 452.65Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, P212121Cell parameters from 9889 reflections
a = 7.6131 (5) Åθ = 3.2–68.3°
b = 11.7216 (7) ŵ = 0.59 mm1
c = 27.7076 (17) ÅT = 150 K
V = 2472.6 (3) Å3Prism, colourless
Z = 40.36 × 0.27 × 0.25 mm
F(000) = 992
Bruker D8 Venture diffractometer4513 independent reflections
Radiation source: micro-focus X-ray source4057 reflections with I > 2σ(I)
Detector resolution: 52.0833 pixels mm-1Rint = 0.061
ω–scansθmax = 68.3°, θmin = 3.2°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)h = −9→8
Tmin = 0.783, Tmax = 0.864k = −13→14
14632 measured reflectionsl = −33→33
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.061w = 1/[σ2(Fo2) + (0.0789P)2 + 0.8039P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.164(Δ/σ)max < 0.001
S = 1.09Δρmax = 0.28 e Å3
4513 reflectionsΔρmin = −0.19 e Å3
304 parametersAbsolute structure: Flack x determined using 1515 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013).
0 restraintsAbsolute structure parameter: 0.2 (3)
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
xyzUiso*/Ueq
O10.7000 (9)0.2747 (4)1.1228 (2)0.127 (2)
O20.2109 (5)0.5554 (3)0.68677 (10)0.0712 (10)
O30.0663 (6)0.3910 (4)0.68208 (13)0.0865 (12)
C10.4287 (7)0.3773 (4)1.02722 (13)0.0568 (11)
H1A0.30120.38721.02160.068*
H1B0.46870.31181.00750.068*
C20.4602 (8)0.3508 (4)1.08081 (14)0.0692 (14)
H2A0.39990.40941.10050.083*
H2B0.40590.27621.08840.083*
C30.6490 (8)0.3471 (4)1.09523 (16)0.0674 (14)
C40.7745 (6)0.4361 (3)1.07509 (13)0.0498 (10)
C50.7231 (6)0.4658 (3)1.02182 (11)0.0415 (8)
H50.75400.39571.00310.050*
C60.8379 (6)0.5589 (3)0.99999 (13)0.0482 (9)
H6A0.96200.54551.00910.058*
H6B0.80220.63391.01310.058*
C70.8213 (5)0.5604 (3)0.94485 (12)0.0443 (8)
H7A0.86730.48760.93190.053*
H7B0.89530.62280.93190.053*
C80.6322 (5)0.5770 (3)0.92684 (11)0.0347 (7)
C90.5071 (5)0.4933 (3)0.95387 (10)0.0372 (8)
H90.54160.41590.94200.045*
C100.5260 (5)0.4859 (3)1.01054 (11)0.0420 (8)
C110.3177 (5)0.5085 (4)0.93680 (12)0.0460 (9)
H11A0.27460.58390.94780.055*
H11B0.24360.44940.95220.055*
C120.2954 (5)0.5006 (3)0.88168 (12)0.0424 (8)
H12A0.31190.42040.87150.051*
H12B0.17430.52350.87300.051*
C130.4255 (5)0.5761 (3)0.85450 (11)0.0326 (7)
H130.39920.65690.86340.039*
C140.6178 (4)0.5509 (3)0.87041 (11)0.0321 (7)
C150.7510 (5)0.6247 (3)0.84160 (12)0.0410 (8)
H15A0.74590.70390.85390.049*
H15B0.87080.59530.84780.049*
C160.7197 (5)0.6269 (4)0.78673 (12)0.0457 (9)
H16A0.79820.68420.77180.055*
H16B0.74960.55140.77300.055*
C170.5299 (5)0.6555 (3)0.77439 (12)0.0405 (8)
C180.4109 (4)0.5670 (3)0.79938 (11)0.0336 (7)
H180.45670.49000.79030.040*
C190.2307 (5)0.5807 (3)0.77408 (12)0.0415 (8)
H190.15220.63340.79250.050*
C200.1359 (5)0.4732 (3)0.76020 (13)0.0460 (9)
C210.2797 (6)0.6321 (4)0.72350 (13)0.0522 (10)
H210.22750.70990.71980.063*
C220.4785 (6)0.6384 (4)0.72141 (12)0.0504 (10)
H22A0.51780.70340.70130.060*
H22B0.52910.56700.70830.060*
C300.1290 (6)0.4657 (5)0.70646 (16)0.0625 (13)
C290.0717 (5)0.3894 (4)0.78608 (15)0.0525 (10)
H29A0.02150.32480.77060.063*
H29B0.07540.39320.82030.063*
C260.5821 (6)0.7027 (3)0.93685 (12)0.0470 (9)
H26A0.61890.72350.96960.071*
H26B0.45460.71180.93390.071*
H26C0.64110.75230.91340.071*
C280.4863 (6)0.7796 (3)0.78893 (14)0.0491 (9)
H28A0.53150.79470.82140.074*
H28B0.35870.79050.78860.074*
H28C0.54100.83240.76600.074*
C270.6651 (5)0.4251 (3)0.85928 (11)0.0382 (8)
H27A0.67670.41500.82430.057*
H27B0.57210.37500.87150.057*
H27C0.77650.40570.87500.057*
C250.4458 (7)0.5894 (4)1.03594 (13)0.0546 (11)
H25A0.33450.60961.02030.082*
H25B0.52710.65401.03380.082*
H25C0.42430.57091.06990.082*
C240.7708 (7)0.5395 (4)1.10971 (13)0.0584 (12)
H24A0.65010.56771.11270.088*
H24B0.84600.60021.09690.088*
H24C0.81400.51611.14150.088*
C230.9581 (8)0.3866 (5)1.07703 (17)0.0815 (18)
H23A0.98340.36051.10990.122*
H23B1.04340.44531.06770.122*
H23C0.96650.32201.05470.122*
U11U22U33U12U13U23
O10.166 (5)0.085 (3)0.131 (4)0.003 (3)−0.022 (4)0.066 (3)
O20.079 (2)0.100 (3)0.0340 (13)0.015 (2)−0.0172 (15)0.0057 (15)
O30.090 (3)0.108 (3)0.062 (2)0.011 (2)−0.0361 (19)−0.023 (2)
C10.084 (3)0.058 (2)0.0289 (17)−0.010 (2)0.0078 (19)0.0033 (16)
C20.116 (4)0.061 (3)0.0311 (19)−0.014 (3)0.013 (2)0.0049 (18)
C30.115 (4)0.041 (2)0.046 (2)0.011 (2)−0.007 (3)0.0053 (18)
C40.076 (3)0.0434 (19)0.0296 (16)0.0128 (19)−0.0052 (17)0.0002 (14)
C50.064 (2)0.0337 (16)0.0270 (15)0.0099 (16)−0.0007 (15)−0.0032 (13)
C60.057 (2)0.050 (2)0.0371 (18)−0.0026 (18)−0.0093 (17)0.0000 (15)
C70.050 (2)0.049 (2)0.0336 (16)−0.0053 (17)−0.0016 (16)0.0048 (15)
C80.0472 (19)0.0259 (14)0.0312 (15)−0.0022 (13)0.0003 (14)−0.0001 (12)
C90.050 (2)0.0376 (17)0.0242 (14)−0.0016 (15)0.0050 (14)−0.0011 (12)
C100.060 (2)0.0402 (18)0.0253 (14)0.0005 (17)0.0048 (15)−0.0029 (13)
C110.045 (2)0.061 (2)0.0320 (16)−0.0069 (17)0.0054 (15)0.0050 (16)
C120.0439 (19)0.050 (2)0.0329 (16)−0.0072 (16)0.0017 (15)0.0037 (15)
C130.0406 (17)0.0297 (15)0.0274 (14)0.0047 (13)0.0028 (13)0.0006 (12)
C140.0400 (17)0.0275 (15)0.0288 (14)0.0006 (13)0.0038 (13)0.0023 (11)
C150.0418 (19)0.0447 (18)0.0364 (17)−0.0028 (15)0.0029 (14)0.0093 (14)
C160.047 (2)0.054 (2)0.0360 (18)0.0031 (17)0.0089 (15)0.0156 (16)
C170.049 (2)0.0415 (18)0.0305 (16)0.0104 (15)0.0075 (15)0.0103 (14)
C180.0394 (18)0.0333 (16)0.0280 (15)0.0087 (14)−0.0002 (13)0.0013 (12)
C190.0452 (19)0.0445 (18)0.0348 (16)0.0176 (15)−0.0005 (15)0.0002 (14)
C200.0397 (19)0.055 (2)0.0432 (19)0.0165 (17)−0.0098 (16)−0.0102 (17)
C210.063 (2)0.058 (2)0.0356 (18)0.024 (2)−0.0016 (17)0.0059 (16)
C220.062 (2)0.061 (2)0.0288 (17)0.0212 (19)0.0064 (16)0.0122 (16)
C300.057 (3)0.087 (3)0.044 (2)0.022 (3)−0.021 (2)−0.014 (2)
C290.043 (2)0.060 (2)0.055 (2)0.0029 (18)−0.0046 (18)−0.0162 (19)
C260.075 (3)0.0307 (17)0.0350 (17)−0.0006 (17)−0.0062 (18)−0.0047 (13)
C280.063 (3)0.0358 (18)0.049 (2)0.0035 (17)0.0063 (19)0.0128 (16)
C270.052 (2)0.0354 (17)0.0271 (14)0.0116 (15)−0.0014 (14)0.0004 (13)
C250.070 (3)0.062 (2)0.0316 (17)0.020 (2)0.0030 (18)−0.0088 (17)
C240.093 (3)0.052 (2)0.0298 (16)0.011 (2)−0.0087 (19)−0.0049 (16)
C230.106 (4)0.095 (4)0.044 (2)0.049 (4)−0.019 (3)−0.010 (2)
O1—C31.206 (6)C14—C151.553 (5)
O2—C301.338 (7)C15—C161.539 (5)
O2—C211.455 (6)C15—H15A0.9900
O3—C301.205 (6)C15—H15B0.9900
C1—C21.536 (5)C16—C171.522 (5)
C1—C101.544 (6)C16—H16A0.9900
C1—H1A0.9900C16—H16B0.9900
C1—H1B0.9900C17—C221.532 (5)
C2—C31.492 (8)C17—C181.542 (5)
C2—H2A0.9900C17—C281.545 (5)
C2—H2B0.9900C18—C191.549 (5)
C3—C41.521 (7)C18—H181.0000
C4—C231.515 (7)C19—C201.502 (6)
C4—C241.546 (5)C19—C211.570 (5)
C4—C51.566 (4)C19—H191.0000
C5—C61.523 (6)C20—C291.311 (6)
C5—C101.550 (6)C20—C301.492 (5)
C5—H51.0000C21—C221.517 (6)
C6—C71.533 (5)C21—H211.0000
C6—H6A0.9900C22—H22A0.9900
C6—H6B0.9900C22—H22B0.9900
C7—C81.536 (5)C29—H29A0.9500
C7—H7A0.9900C29—H29B0.9500
C7—H7B0.9900C26—H26A0.9800
C8—C261.546 (5)C26—H26B0.9800
C8—C91.559 (5)C26—H26C0.9800
C8—C141.597 (4)C28—H28A0.9800
C9—C111.528 (5)C28—H28B0.9800
C9—C101.579 (4)C28—H28C0.9800
C9—H91.0000C27—H27A0.9800
C10—C251.530 (5)C27—H27B0.9800
C11—C121.539 (4)C27—H27C0.9800
C11—H11A0.9900C25—H25A0.9800
C11—H11B0.9900C25—H25B0.9800
C12—C131.527 (5)C25—H25C0.9800
C12—H12A0.9900C24—H24A0.9800
C12—H12B0.9900C24—H24B0.9800
C13—C181.535 (4)C24—H24C0.9800
C13—C141.557 (5)C23—H23A0.9800
C13—H131.0000C23—H23B0.9800
C14—C271.549 (4)C23—H23C0.9800
C30—O2—C21111.6 (3)C16—C15—H15B108.6
C2—C1—C10112.4 (4)C14—C15—H15B108.6
C2—C1—H1A109.1H15A—C15—H15B107.6
C10—C1—H1A109.1C17—C16—C15111.9 (3)
C2—C1—H1B109.1C17—C16—H16A109.2
C10—C1—H1B109.1C15—C16—H16A109.2
H1A—C1—H1B107.8C17—C16—H16B109.2
C3—C2—C1114.5 (4)C15—C16—H16B109.2
C3—C2—H2A108.6H16A—C16—H16B107.9
C1—C2—H2A108.6C16—C17—C22115.4 (3)
C3—C2—H2B108.6C16—C17—C18108.0 (3)
C1—C2—H2B108.6C22—C17—C18101.1 (3)
H2A—C2—H2B107.6C16—C17—C28110.7 (4)
O1—C3—C2120.0 (6)C22—C17—C28108.5 (3)
O1—C3—C4120.9 (6)C18—C17—C28112.9 (3)
C2—C3—C4119.1 (4)C13—C18—C17111.0 (3)
C23—C4—C3107.7 (4)C13—C18—C19120.5 (3)
C23—C4—C24107.2 (4)C17—C18—C19104.3 (3)
C3—C4—C24107.4 (4)C13—C18—H18106.8
C23—C4—C5110.4 (3)C17—C18—H18106.8
C3—C4—C5110.0 (4)C19—C18—H18106.8
C24—C4—C5113.9 (3)C20—C19—C18117.0 (3)
C6—C5—C10111.5 (3)C20—C19—C21101.9 (3)
C6—C5—C4113.0 (3)C18—C19—C21103.5 (3)
C10—C5—C4117.7 (3)C20—C19—H19111.2
C6—C5—H5104.3C18—C19—H19111.2
C10—C5—H5104.3C21—C19—H19111.2
C4—C5—H5104.3C29—C20—C30119.2 (4)
C5—C6—C7110.9 (3)C29—C20—C19131.9 (3)
C5—C6—H6A109.5C30—C20—C19108.8 (4)
C7—C6—H6A109.5O2—C21—C22111.3 (3)
C5—C6—H6B109.5O2—C21—C19107.6 (4)
C7—C6—H6B109.5C22—C21—C19106.9 (3)
H6A—C6—H6B108.0O2—C21—H21110.3
C6—C7—C8113.7 (3)C22—C21—H21110.3
C6—C7—H7A108.8C19—C21—H21110.3
C8—C7—H7A108.8C21—C22—C17103.0 (3)
C6—C7—H7B108.8C21—C22—H22A111.2
C8—C7—H7B108.8C17—C22—H22A111.2
H7A—C7—H7B107.7C21—C22—H22B111.2
C7—C8—C26107.0 (3)C17—C22—H22B111.2
C7—C8—C9109.7 (3)H22A—C22—H22B109.1
C26—C8—C9111.3 (3)O3—C30—O2121.8 (4)
C7—C8—C14111.0 (3)O3—C30—C20128.1 (5)
C26—C8—C14110.0 (3)O2—C30—C20110.1 (4)
C9—C8—C14107.9 (2)C20—C29—H29A120.0
C11—C9—C8110.7 (3)C20—C29—H29B120.0
C11—C9—C10113.6 (3)H29A—C29—H29B120.0
C8—C9—C10117.1 (3)C8—C26—H26A109.5
C11—C9—H9104.6C8—C26—H26B109.5
C8—C9—H9104.6H26A—C26—H26B109.5
C10—C9—H9104.6C8—C26—H26C109.5
C25—C10—C1108.9 (3)H26A—C26—H26C109.5
C25—C10—C5114.5 (3)H26B—C26—H26C109.5
C1—C10—C5106.2 (3)C17—C28—H28A109.5
C25—C10—C9112.2 (3)C17—C28—H28B109.5
C1—C10—C9107.4 (3)H28A—C28—H28B109.5
C5—C10—C9107.3 (3)C17—C28—H28C109.5
C9—C11—C12113.8 (3)H28A—C28—H28C109.5
C9—C11—H11A108.8H28B—C28—H28C109.5
C12—C11—H11A108.8C14—C27—H27A109.5
C9—C11—H11B108.8C14—C27—H27B109.5
C12—C11—H11B108.8H27A—C27—H27B109.5
H11A—C11—H11B107.7C14—C27—H27C109.5
C13—C12—C11112.5 (3)H27A—C27—H27C109.5
C13—C12—H12A109.1H27B—C27—H27C109.5
C11—C12—H12A109.1C10—C25—H25A109.5
C13—C12—H12B109.1C10—C25—H25B109.5
C11—C12—H12B109.1H25A—C25—H25B109.5
H12A—C12—H12B107.8C10—C25—H25C109.5
C12—C13—C18113.8 (3)H25A—C25—H25C109.5
C12—C13—C14111.1 (3)H25B—C25—H25C109.5
C18—C13—C14109.7 (3)C4—C24—H24A109.5
C12—C13—H13107.3C4—C24—H24B109.5
C18—C13—H13107.3H24A—C24—H24B109.5
C14—C13—H13107.3C4—C24—H24C109.5
C27—C14—C15106.0 (3)H24A—C24—H24C109.5
C27—C14—C13110.0 (3)H24B—C24—H24C109.5
C15—C14—C13111.3 (3)C4—C23—H23A109.5
C27—C14—C8111.2 (2)C4—C23—H23B109.5
C15—C14—C8110.6 (3)H23A—C23—H23B109.5
C13—C14—C8107.8 (2)C4—C23—H23C109.5
C16—C15—C14114.6 (3)H23A—C23—H23C109.5
C16—C15—H15A108.6H23B—C23—H23C109.5
C14—C15—H15A108.6
C10—C1—C2—C3−52.1 (6)C18—C13—C14—C8172.8 (2)
C1—C2—C3—O1−139.3 (5)C7—C8—C14—C2762.4 (4)
C1—C2—C3—C441.2 (6)C26—C8—C14—C27−179.3 (3)
O1—C3—C4—C2324.3 (6)C9—C8—C14—C27−57.8 (4)
C2—C3—C4—C23−156.2 (4)C7—C8—C14—C15−55.1 (3)
O1—C3—C4—C24−90.8 (6)C26—C8—C14—C1563.2 (4)
C2—C3—C4—C2488.7 (5)C9—C8—C14—C15−175.3 (3)
O1—C3—C4—C5144.7 (5)C7—C8—C14—C13−176.9 (3)
C2—C3—C4—C5−35.8 (5)C26—C8—C14—C13−58.7 (4)
C23—C4—C5—C6−64.0 (5)C9—C8—C14—C1362.9 (3)
C3—C4—C5—C6177.2 (3)C27—C14—C15—C1672.7 (4)
C24—C4—C5—C656.6 (5)C13—C14—C15—C16−46.9 (4)
C23—C4—C5—C10163.7 (4)C8—C14—C15—C16−166.6 (3)
C3—C4—C5—C1044.9 (4)C14—C15—C16—C1750.6 (4)
C24—C4—C5—C10−75.7 (5)C15—C16—C17—C22−169.3 (3)
C10—C5—C6—C7−61.6 (4)C15—C16—C17—C18−57.2 (4)
C4—C5—C6—C7163.1 (3)C15—C16—C17—C2866.9 (4)
C5—C6—C7—C857.3 (4)C12—C13—C18—C17173.2 (3)
C6—C7—C8—C2672.4 (4)C14—C13—C18—C17−61.6 (3)
C6—C7—C8—C9−48.5 (4)C12—C13—C18—C1951.0 (4)
C6—C7—C8—C14−167.6 (3)C14—C13—C18—C19176.2 (3)
C7—C8—C9—C11179.7 (3)C16—C17—C18—C1364.1 (4)
C26—C8—C9—C1161.4 (4)C22—C17—C18—C13−174.3 (3)
C14—C8—C9—C11−59.3 (3)C28—C17—C18—C13−58.6 (4)
C7—C8—C9—C1047.2 (4)C16—C17—C18—C19−164.7 (3)
C26—C8—C9—C10−71.1 (4)C22—C17—C18—C19−43.1 (3)
C14—C8—C9—C10168.2 (3)C28—C17—C18—C1972.6 (4)
C2—C1—C10—C25−66.7 (5)C13—C18—C19—C20−98.8 (4)
C2—C1—C10—C557.0 (5)C17—C18—C19—C20135.8 (3)
C2—C1—C10—C9171.6 (4)C13—C18—C19—C21150.0 (3)
C6—C5—C10—C25−68.7 (4)C17—C18—C19—C2124.7 (3)
C4—C5—C10—C2564.3 (4)C18—C19—C20—C2963.3 (5)
C6—C5—C10—C1171.1 (3)C21—C19—C20—C29175.3 (4)
C4—C5—C10—C1−56.0 (4)C18—C19—C20—C30−113.1 (3)
C6—C5—C10—C956.5 (4)C21—C19—C20—C30−1.0 (4)
C4—C5—C10—C9−170.6 (3)C30—O2—C21—C22116.4 (4)
C11—C9—C10—C25−55.7 (4)C30—O2—C21—C19−0.3 (4)
C8—C9—C10—C2575.5 (4)C20—C19—C21—O20.8 (4)
C11—C9—C10—C164.0 (4)C18—C19—C21—O2122.7 (3)
C8—C9—C10—C1−164.8 (3)C20—C19—C21—C22−118.8 (4)
C11—C9—C10—C5177.8 (3)C18—C19—C21—C223.1 (4)
C8—C9—C10—C5−51.0 (4)O2—C21—C22—C17−146.9 (3)
C8—C9—C11—C1253.1 (4)C19—C21—C22—C17−29.8 (4)
C10—C9—C11—C12−172.7 (3)C16—C17—C22—C21160.8 (3)
C9—C11—C12—C13−49.7 (4)C18—C17—C22—C2144.7 (4)
C11—C12—C13—C18178.0 (3)C28—C17—C22—C21−74.3 (4)
C11—C12—C13—C1453.6 (4)C21—O2—C30—O3−178.3 (4)
C12—C13—C14—C2760.9 (3)C21—O2—C30—C20−0.4 (5)
C18—C13—C14—C27−65.8 (3)C29—C20—C30—O31.8 (7)
C12—C13—C14—C15178.1 (3)C19—C20—C30—O3178.7 (4)
C18—C13—C14—C1551.4 (3)C29—C20—C30—O2−176.0 (4)
C12—C13—C14—C8−60.5 (3)C19—C20—C30—O20.9 (5)
D—H···AD—HH···AD···AD—H···A
C2—H2A···O2i0.992.573.395 (5)141
C12—H12A···O1ii0.992.453.310 (6)146
C24—H24A···O3i0.982.583.357 (6)137
  9 in total

1.  The telescoped intramolecular michael/olefination (TIMO) approach to alpha-alkylidene-gamma-butyrolactones: synthesis of (+)-paeonilactone B.

Authors:  Michael G Edwards; Martin N Kenworthy; Russell R A Kitson; Mark S Scott; Richard J K Taylor
Journal:  Angew Chem Int Ed Engl       Date:  2008       Impact factor: 15.336

2.  Isolation, Structural Modification, and HIV Inhibition of Pentacyclic Lupane-Type Triterpenoids from Cassine xylocarpa and Maytenus cuzcoina.

Authors:  Oliver Callies; Luis M Bedoya; Manuela Beltrán; Alejandro Muñoz; Patricia Obregón Calderón; Alex A Osorio; Ignacio A Jiménez; José Alcamí; Isabel L Bazzocchi
Journal:  J Nat Prod       Date:  2015-04-30       Impact factor: 4.050

3.  Lupane derivatives from Lophopetalum wallichii with farnesyl protein transferase inhibitory activity.

Authors:  S Sturm; R R Gil; H B Chai; O D Ngassapa; T Santisuk; V Reutrakul; A Howe; M Moss; J M Besterman; S L Yang; J E Farthing; R M Tait; J A Lewis; M J O'Neill; N R Farnsworth; G A Cordell; J M Pezzuto; A D Kinghorn
Journal:  J Nat Prod       Date:  1996-07       Impact factor: 4.050

4.  New cytotoxic lupane lactones from Kokoona ochracea.

Authors:  O D Ngassapa; D D Soejarto; C T Che; J M Pezzuto; N R Farnsworth
Journal:  J Nat Prod       Date:  1991 Sep-Oct       Impact factor: 4.050

5.  Comparison of silver and molybdenum microfocus X-ray sources for single-crystal structure determination.

Authors:  Lennard Krause; Regine Herbst-Irmer; George M Sheldrick; Dietmar Stalke
Journal:  J Appl Crystallogr       Date:  2015-01-30       Impact factor: 3.304

6.  SHELXT - integrated space-group and crystal-structure determination.

Authors:  George M Sheldrick
Journal:  Acta Crystallogr A Found Adv       Date:  2015-01-01       Impact factor: 2.290

7.  Use of intensity quotients and differences in absolute structure refinement.

Authors:  Simon Parsons; Howard D Flack; Trixie Wagner
Journal:  Acta Crystallogr B Struct Sci Cryst Eng Mater       Date:  2013-05-17

8.  Structure validation in chemical crystallography.

Authors:  Anthony L Spek
Journal:  Acta Crystallogr D Biol Crystallogr       Date:  2009-01-20

9.  The Cambridge Structural Database.

Authors:  Colin R Groom; Ian J Bruno; Matthew P Lightfoot; Suzanna C Ward
Journal:  Acta Crystallogr B Struct Sci Cryst Eng Mater       Date:  2016-04-01
  9 in total
  1 in total

Review 1.  Pentacyclic Triterpenoids Isolated from Celastraceae: A Focus in the 13C-NMR Data.

Authors:  Karen Caroline Camargo; Mariana Guerra de Aguilar; Acácio Raphael Aguiar Moraes; Raquel Goes de Castro; Daiane Szczerbowski; Elizabeth Luciana Marinho Miguel; Leila Renan Oliveira; Grasiely Faria Sousa; Diogo Montes Vidal; Lucienir Pains Duarte
Journal:  Molecules       Date:  2022-01-31       Impact factor: 4.411

  1 in total

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