4,5,7,8,17-Penta­hydr­oxy-14,18-dimethyl-6-methyl­ene-3,10-dioxapenta­cyclo­[9.8.0.01,7.04,19.013,18]nona­dec-14-ene-9,16-dione methanol solvate dihydrate

Chin Hoe Teh; Siew Chin Teoh; Chin Sing Yeap; Kit Lam Chan; Hoong-Kun Fun

doi:10.1107/S1600536809010502

. 2009 Mar 28;65(Pt 4):o898–o899. doi: 10.1107/S1600536809010502

4,5,7,8,17-Pentahydroxy-14,18-dimethyl-6-methylene-3,10-dioxapentacyclo[9.8.0.0^1,7.0^4,19.0^13,18]nonadec-14-ene-9,16-dione methanol solvate dihydrate

Chin Hoe Teh ^a, Siew Chin Teoh ^b, Chin Sing Yeap ^b, Kit Lam Chan ^a,^‡, Hoong-Kun Fun ^b,^*

PMCID: PMC2968991 PMID: 21582604

Abstract

The title quassinoid compound, C₂₀H₂₄O₉·CH₃OH·2H₂O, is a natural eurycomanone isolated from the roots of Eurycoma longifolia. The molecules contain a fused five-ring system, with one tetrahydrofuran ring adopting an envelope conformation, one tetrahydropyran-2-one ring in a screw boat conformation, one cyclohexenone ring in a half-chair conformation and two cyclohexane rings in chair conformations. Intramolecular C—H⋯O interactions generate S(5) ring motifs and an O—H⋯O interaction generates an S(7) ring motif. In the crystal, molecules are linked via intermolecular O—H⋯O interactions along the b axis and further stacked along a axis. The absolute configuration of the title compound was inferred from previously solved structures of its analogues.

Related literature

For bond-length data, see Allen et al. (1987 ▶). For hydrogen-bond motifs, see Bernstein et al. (1995 ▶). For ring conformations, see Cremer & Pople (1975 ▶). For quassinoids and bioactivity, see Itokawa et al. (1993 ▶); Chan et al. (1992 ▶); Kardono et al. (1991 ▶); Itokawa et al. (1992 ▶); Morita et al. (1992 ▶); Morita et al. (1993 ▶); Tada et al. (1991 ▶); Ang et al. (1995 ▶); Chan et al. (2004 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₀H₂₄O₉·CH₄O·2H₂O
M _r = 476.47
Orthorhombic,
a = 9.1817 (1) Å
b = 10.7806 (2) Å
c = 21.7817 (3) Å
V = 2156.04 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 100 K
0.43 × 0.28 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.950, T _max = 0.987
27636 measured reflections
3577 independent reflections
3352 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.127
S = 1.09
3577 reflections
307 parameters
H-atom parameters constrained
Δρ_max = 1.08 e Å⁻³
Δρ_min = −0.46 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809010502/at2747sup1.cif

e-65-0o898-sup1.cif^{(26.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809010502/at2747Isup2.hkl

e-65-0o898-Isup2.hkl^{(175.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W1⋯O4ⁱ	0.88	1.94	2.810 (2)	169
O2—H2⋯O2Wⁱⁱ	0.82	1.85	2.656 (3)	169
O1W—H2W1⋯O3ⁱⁱⁱ	0.84	2.06	2.873 (3)	163
O3—H3⋯O2	0.82	1.71	2.525 (2)	171
O2W—H1W2⋯O8	0.95	2.03	2.950 (3)	164
O2W—H2W2⋯O10	0.85	1.91	2.760 (3)	179
O5—H5⋯O3^iv	0.82	1.99	2.805 (2)	172
O6—H6⋯O9^v	0.82	2.14	2.848 (2)	144
O7—H7⋯O1W^vi	0.82	1.84	2.653 (3)	171
O10—H10⋯O7^vii	0.82	2.29	3.011 (3)	147
O10—H10⋯O8^vii	0.82	2.23	2.911 (3)	140
C1—H1A⋯O9	0.98	2.48	2.936 (3)	108
C1—H1A⋯O1ⁱⁱⁱ	0.98	2.56	3.507 (3)	162
C7—H7A⋯O5	0.98	2.38	2.856 (3)	109
C12—H12A⋯O1ⁱⁱⁱ	0.98	2.47	3.168 (3)	128
C17—H17A⋯O10^v	0.97	2.60	3.428 (3)	144
C17—H17B⋯O6	0.97	2.50	2.929 (3)	107
C19—H19B⋯O2	0.96	2.56	2.957 (3)	105

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

Acknowledgments

KLC and CHT thank Universiti Sains Malaysia for a Research University grant No. 1001/PFARMASI/813006. HKF and SCT thank Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. YCS thanks Universiti Sains Malaysia for a studentship award.

supplementary crystallographic information

Comment

Eurycoma longifolia Jack is a tall, slender shrub-tree, commonly found in lowland forests below 500 meters above sea level in Southeast Asia. The roots of this Simaroubaceae plant are used in folk medicine for intermittent fever (malaria), dysentery, glandular swelling and aphrodisiac properties. Various classes of chemical constituents (Itokawa et al., 1993, Chan et al., 1992, Kardono et al., 1991, Itokawa et al., 1992, Morita et al., 1992, Morita et al., 1993) have been identified and some have shown antiulcer (Tada et al., 1991), cytotoxic (Kardono et al., 1991, Itokawa et al., 1992) and antimalarial (Ang et al., 1995, Chan et al., 2004) activities. In our continuing search for the bioactive compounds from E. longifolia, we have isolated eurycomanone (1), a quassinoid in crystalline form.

The title compound (Fig. 1), contains quassinoid, one molecule of methanol and two molecules of water solvents. The bond lengths and angles are within normal ranges (Allen et al., 1987). The molecule of the title compound contains a fused five-ring system A/B/C/D/E (Scheme 1). The A/B and B/D junctions are trans-fused, whereas B/C, B/E and C/D are cis-fused (Fig 1). The cyclohexenone ring A (C1—C6) has a half-chair conformation with puckering parameters of Q = 0.507 (2) Å, Θ = 130.2 (3)° and φ = 97.3 (4)°. The cyclohexane ring B (C1-C6-C7-C16-C14-C15) and D (C7-C8-C9-C10-C11-C16) adopt a chair conformation with puckering parameters of Q = 0.565 (2) Å, Θ = 154.6 (3)° and φ = 179.8 (6)° and Q = 0.660 (2) Å, Θ = 151.68 (17)° and φ = 183.1 (4)° respectively. The tetrahydro-pyran-2-one ring C (O9-C13-C12-C11-C16-14) has a screw boat conformation with puckering parameters Q = 0.502 (3) Å, Θ = 38.4 (2)° and φ = 193.4 (5)°. The tetrahydro-furan ring E (C7-C8-O4-C17-C16) is in an envelope conformation with puckering parameters of Q = 0.450 (2) Å and φ = 254.5 (3)°.

The intramolecular interactions C1—H1A···O9, C17—H17B···O6, C19—H19B···O2 and C7—H7A···O5 generate S(5) ring motifs, and O3—H3···O2 generates an S(7) ring motif (Bernstein et al., 1995). The crystal packing shows that the molecules were linked via intermolecular O—H···O interactions along b axis and further stacked along a axis (Fig 2). The absolute configuration of the title compound was inferred from previously solved structures of its analogues (Tada et al., 1991).

Experimental

The air-dried powdered roots of E. longifolia (11.6 kg) were extracted with MeOH. The MeOH extract on evaporation to dryness yielded 485 g of dark brown residue which was next chromatographed on a Diaion HP 20 column using H₂O-MeOH (1:0 - 0:1) gradient mixtures to afford 4 fractions (Fr 1 - 4). Fr 2 was concentrated under vacuum to give 52.2 g of residue. The residue was resuspended in water and then partitioned successively with ethyl acetate and saturated n-butanol to yield three subfractions. The n-BuOH subfraction (20.4 g) was further fractionated on a silica gel column using CHCl₃-MeOH (1:0 - 1:1) gradient mixtures to obtain 7 portions (A1-A7). A3 was further purified by centrifugal silica gel TLC with CHCl₃-MeOH (1:0 - 1:1) gradient mixtures. Upon solvent removal, the residue obtained on subsequent recrystallization from CHCl₃-MeOH (9:1, v/v) at room temperature afforded 1 as colourless crystals (75.3 mg).