Crystal structure of 16-hy­droxy-4,4,10,13,14-penta­methyl-17-(6-methyl­hept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodeca­hydro-1H-cyclo­penta­[a]phenanthren-3(2H)-one

Jun-Jun Ge; Pian Chen; Xiao-Xia Ye

doi:10.1107/S2056989015010592

. 2015 Jun 13;71(Pt 7):o464–o465. doi: 10.1107/S2056989015010592

Crystal structure of 16-hydroxy-4,4,10,13,14-pentamethyl-17-(6-methylhept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3(2H)-one

Jun-Jun Ge ^a, Pian Chen ^a, Xiao-Xia Ye ^a,^*

PMCID: PMC4518949 PMID: 26279910

Abstract

The title compound, C₃₀H₄₈O₂, contains a fused four-ring triterpenoid system. In the molecule, the two cyclohexane rings adopt a chair conformation and a twist boat conformation, respectively, the central cyclohexene ring adopts a half-chair conformation whereas the five membered ring adopts an envelope conformation. In the crystal, O—H⋯O hydrogen bonds between the hydroxy and carbonyl groups of adjacent molecules link the molecules into supramolecular chains propagating along the b-axis direction.

Keywords: crystal structure, triterpenoid, Melia azedarach, O—H⋯O hydrogen bonds

Related literature

For biological applications of triterpenoid compounds, see: Faizi et al. (2002 ▸); Wang et al. (2011 ▸); Dong et al. (2012 ▸). For isolation of the title compound from the barks of Melia azedarach, see: Chang & Chiang (1969 ▸). graphic file with name e-71-0o464-scheme1.jpg

Experimental

Crystal data

C₃₀H₄₈O₂
M _r = 440.68
Orthorhombic,
a = 12.436 (7) Å
b = 13.571 (7) Å
c = 16.159 (9) Å
V = 2727 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 298 K
0.31 × 0.25 × 0.22 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2002 ▸) T _min = 0.980, T _max = 0.986
12873 measured reflections
3000 independent reflections
2320 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.058
wR(F ²) = 0.198
S = 1.08
3000 reflections
298 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: APEX2 (Bruker, 2002 ▸); cell refinement: SAINT (Bruker, 2002 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▸); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989015010592/xu5852sup1.cif

e-71-0o464-sup1.cif^{(27KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015010592/xu5852Isup2.hkl

e-71-0o464-Isup2.hkl^{(147.3KB, hkl)}

Click here for additional data file.^{(1.3MB, tif)}

. DOI: 10.1107/S2056989015010592/xu5852fig1.tif

The molecular structure of (I) with the atom numbering, showing displacement ellipsoids at the 50% probability level.

CCDC reference: 1404443

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
O2H2O1ⁱ	0.82	2.11	2.894(4)	160

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported financially by a grant from the Natural Sciences Foundation of Zhejiang, China (No. LY12B02007).

supplementary crystallographic information

S1. Introduction

Melia azedarach Linn. (Meliaceae), a high tree, enjoys a broad distribution in the most parts of China. The triterpenoids which isolated from this plant is well known for its pharmacological properties, such as analgesic, anticancer, antiviral, antimalarial, antibacterial and antifeedant activities (Faizi et al., 2002; Wang et al., 2011; Dong et al., 2012). The title compound, 16-hydroxy-4,4,10,13,14-pentamethyl -17-(6-methylhept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodecahydro -1H-cyclopenta [α]phenanthren-3(2H)-one (I) (Fig. 1) was isolated from the barks of Melia azedarach (Chiang & Chang, 1969). In this work, we obtained a single-crystal of (I) and present here its crystal structure.

The title compound contains a fused four-ring triterpenoid system. rings A adopt a chair conformation, while ring B with one double bond adopts a half-chair conformation, ring C adopts a twist boat conformation and ring D adopts an envelope conformation. Intermolecular O—H···O hydrogen bonds are present in the crystal structure (Table 1).

S2. Isolation and crystallization

The air-dried and powered barks of Melia azedarach L.(10.6kg) were percolated with 95% aqueous ethanol for 7 days at room temperature for three times. After evaporation of the solvent under reduced pressure, the gummy residue was suspended in water and then partitioned with EtOAc. The EtOAc extract (145g) was subjected to CC on silica gel eluting with petroleum ether-EtOAc (from 20:1 to 2:1, v/v) to give fifteen fractions (1-15). Fraction 5 (22g) was further separated on silica gel CC and eluted with petroleum-acetone from 20:1 to 3:1, yielding five sub-fractions (2a-2e). Sub-fraction 2c (3.25g), subjected to a series of purification steps using silica gel CC, Sephadex LH-20 to afford Sub-fraction 2c-b-b-b (120.4mg) , then use semi-preparative HPLC (MeCN/H2O 90:10, flow rate 3.8 mL/min) to afford (I) (16.8mg, t _R = 32.5min). The structures of (I) was elucidated by means of NMR. Colourless crystal were obtained in the freezer after one month by slow evaporation from acetone/methanol [10:1 (v/v)] mixture solution.

S3. Refinement

H-atoms bound to carbon were placed in calculated positions with C—H = 0.93–0.98 Å, and refined in riding mode with U_iso(H) = 1.5U_eq(C) for methyl H atoms and 1.2U_eq(C) for the others. Hydroxy H atoms was placed in calculated position with O—-H = 0.82 Å, and refined in riding mode with U_iso(H) = 1.5U_eq(O). The absolute structure has not been determined as no significant anomalous scattering, equivalent diffractions were merged.