Redetermination and absolute configuration of 7α-hy­droxy­royleanone

Razak, I.A.; Salae, A.W.; Chantrapromma, S.; Karalai, C.; Fun, H.-K.

doi:10.1107/S1600536810020544

organic compounds

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ISSN: 2056-9890

Volume 66| Part 7| July 2010| Pages o1566-o1567

doi:10.1107/S1600536810020544

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Redetermination and absolute configuration of 7α-hydroxyroyleanone

Ibrahim Abdul Razak,^a Abdul Wahab Salae,^b Suchada Chantrapromma,^b ‡ Chatchanok Karalai ^b and Hoong-Kun Fun ^a ^*§

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bCrystal Materials Research Unit, Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand
^*Correspondence e-mail: hkfun@usm.my

(Received 25 May 2010; accepted 30 May 2010; online 5 June 2010)

The title compound [systematic name: 7α,12-dihydroxy-8,12-abietadiene,11,14-dione or (4bS,8aS,10R)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl-1,4,4b,5,6,7,8,8a,9,10-decahydrophenanthrene-1,4-dione], C₂₀H₂₈O₄, is an abietane diterpenoid, which was isolated from the roots of Premna obtusifolia (Verbenaceae). Its crystal structure has been reported previously [Chen et al. (2000 ). Jiegou Huaxue, 19, 122–125], but the absolute configuration could not be determined using data collected with Mo radiation. This redetermination using Cu radiation shows the the absolute configurations of the stereogenic centres at positions 4b, 8a and 10 to be S, S and R, respectively. Two intramolecular O—H⋯O hydrogen bonds [one generating an S(5) ring and one generating an S(6) ring] and a number of short C—H⋯O contacts occur. In the crystal, molecules are linked into infinite chains propagating in [100] by O—H⋯O hydrogen bonds and weak C—H⋯O interactions.

Related literature

For background to Verbenaceae, diterpenes and their biological activity, see: Batista et al. (1994 ); Bunluepuech & Tewtrakul (2009 ); Jonathan et al. (1989 ); Kabouche et al. (2007 ); Kupchan et al. (1968 , 1969 ); Nagy et al. (1999 ); Ulubelen et al. (2001 ). For the previous structure determination, see: Chen et al. (2000). For hydrogen-bond motifs, see: Bernstein et al. (1995 ) and for ring conformations, see: Cremer & Pople (1975 ). For bond-length data, see: Allen et al. (1987 ). For the stability of the temperature controller used in the data collection, see Cosier & Glazer (1986 ).

Experimental

Crystal data

C₂₀H₂₈O₄
M_r = 332.42
Orthorhombic, P 2₁ 2₁ 2₁
a = 7.6729 (1) Å
b = 9.3972 (1) Å
c = 24.1946 (3) Å
V = 1744.52 (4) Å³
Z = 4
Cu Kα radiation
μ = 0.70 mm⁻¹
T = 100 K
0.28 × 0.28 × 0.20 mm

Data collection

Bruker APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.829, T_max = 0.871
6475 measured reflections
2578 independent reflections
2564 reflections with I > 2σ(I)
R_int = 0.015

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.074
S = 1.04
2578 reflections
230 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.13 e Å⁻³
Absolute structure: Flack (1983 ), 970 Friedel pairs
Flack parameter: 0.13 (16)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯O2ⁱ	0.88 (2)	2.24 (3)	2.9502 (15)	137 (2)
O1—H1O1⋯O4	0.88 (2)	2.52 (3)	2.9399 (14)	109.8 (19)
O3—H1O3⋯O2	0.83 (2)	2.075 (19)	2.5892 (14)	119.8 (19)
O3—H1O3⋯O4ⁱⁱ	0.83 (2)	2.42 (2)	3.1635 (14)	148.8 (18)
C1—H1A⋯O2	0.97	2.33	2.9493 (18)	121
C5—H5A⋯O1	0.98	2.52	2.9933 (17)	110
C7—H7A⋯O2ⁱ	0.98	2.42	3.0998 (17)	126
C15—H15A⋯O4	0.98	2.38	2.8549 (17)	109
C16—H16C⋯O3	0.96	2.58	3.1654 (19)	119
C17—H17B⋯O3	0.96	2.53	3.1204 (18)	119
C20—H20A⋯O2	0.96	2.51	3.1451 (18)	124
Symmetry codes: (i) x-1, y, z; (ii) x+1, y, z.

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); 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 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810020544/hb5468sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810020544/hb5468Isup2.hkl

checkCIF report

Comment top

The extracts of Verbenaceae plants were found to possess anti-HIV-1 integrase activity (Bunluepuech & Tewtrakul, 2009). Premna obtusifolia (Verbenaceae), a small tree found in the mangrove forests, is one of the Verbenaceae plants. As part of our study of chemical constituents and bioactive compounds from the roots of Premna obtusifolia (Verbenaceae) which were collected from Satun province in the southern part of Thailand, the title abietane diterpenoid (I) was isolated. It was known as horminone (Batista et al., 1994) or 7α-hydroxyroyleanone (Nagy et al., 1999) and the previous reports show that (I) exhibits significant biological activities as tumor inhibitors (Kupchan et al., 1968, 1969; Jonathan et al., 1989), antioxidant (Kabouche et al., 2007) and antibacterial agents (Ulubelen et al., 2001). The crystal structure of (I) has been reported (Chen et al., 2000) but the absolute configuration could not be determined due to no large anomalous dispersion using a data set collected with Mo radiation. Our data of (I) was collected using Cu radiation with Bruker Apex-Duo CCD diffractometer and the absolute configuration at atoms C10, C5 and C7 (or positions 4b, 8a and 10 of abietane diterpenoid) were determined as S,S,R making use of the large anomalous scattering of Cu Kα X-radiation with the Flack parameter being refined to 0.13 (16). We report herein the crystal structure of (I) determined from the Cu data.

The molecule of (I) has three fused six membered rings (Fig. 1). The two cyclohexanes rings are trans fused. One cyclohexane ring (C1–C5/C10) is in a standard chair conformation whereas the other (C5–C10) is in half chair conformation, with the puckering parameter Q = 0.5419 (15) Å, θ = 51.68 (16)° and ϕ = 21.6 (2)° (Cremer & Pople, 1975). The benzoquinone ring (C8–C9/C11–C14/O2/O4) is slightly twisted with the maximum deviations of 0.060 (1) and -0.052 (1) Å for atoms C9 and C11, respectively. The O2, O3 and O4 atoms lie close to the mean plane of the C8–C9/C11–C14 ring with the r.m.s. of 0.0543 (1). The bond angles around C11 and C14 are indicative of sp² hybridization for these atoms. The orientation of the propanyl group is described by the torsion angles C14–C13–C15–C17 = -118.43 (14)° and C14–C13–C15–C16 = 116.53 (14)°. Intramolecular O1—H1O1···O4 and O3—H1O3···O2 hydrogen bonds (Table 1) generate S(6) and S(5) ring motifs, respectively (Fig. 1) (Bernstein et al., 1995). The bond distances in (I) are within normal ranges (Allen et al., 1987).

The crystal packing of (I) is stabilized by intermolecular O—H···O hydrogen bonds and weak C—H···O interactions (Fig. 2 and Table 1). The molecules are linked into infinite one dimensional chains along the [1 0 0] (Fig. 2) through O1—H1O1···O2 and O3—H1O3···O4 hydrogen bonds and weak C7—H7A···O2 interactions (Table 1).

Related literature top

For background to Verbenaceae, diterpenes and their biological activity, see: Batista et al. (1994); Bunluepuech & Tewtrakul (2009); Jonathan et al. (1989); Kabouche et al. (2007); Kupchan et al. (1968, 1969); Nagy et al. (1999); Ulubelen et al. (2001). For the previous structure determination, see: Chen et al. (2000). For hydrogen-bond motifs, see: Bernstein et al. (1995) and for ring conformations, see: Cremer & Pople (1975). For bond-length data, see: Allen et al. (1987). For the stability of the temperature controller used in the data collection, see Cosier & Glazer (1986).

Experimental top

The air-dried roots of premna obtusifolia (4.5 kg) were extracted with CH₂Cl₂ (2 × 20 L) at room temperature. The combined extracts were concentrated under reduced pressure to afford a dark yellow extract (40.5 g) which was subjected to quick column chromatography (QCC) over silica gel using solvents of increasing polarity from n-hexane to EtOAc to afford 12 fractions (F1—F12). Fraction F4 was further purified by QCC using hexane-acetone (9:1), yielding the title compound (57.5 mg). Yellow blocks of (I) were recrystallized from n-hexane after several days.

Computing details top

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

Figures top

	Fig. 1. The structure of (I), showing 50% probability displacement ellipsoids. Intramolecular O—H···O hydrogen bonds are shown as dashed lines.
	Fig. 2. The crystal packing of (I) viewed along the b axis, showing one dimensional chains along the [1 0 0]. Hydrogen bonds are shown as dashed lines.

(4bS,8aS,10R)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl- 1,4,4b,5,6,7,8,8a,9,10-decahydrophenanthrene-1,4-dione top

Crystal data top

C₂₀H₂₈O₄	F(000) = 720
M_r = 332.42	D_x = 1.266 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2578 reflections
a = 7.6729 (1) Å	θ = 5.1–62.5°
b = 9.3972 (1) Å	µ = 0.70 mm⁻¹
c = 24.1946 (3) Å	T = 100 K
V = 1744.52 (4) Å³	Block, yellow
Z = 4	0.28 × 0.28 × 0.20 mm

Data collection top

Bruker APEXII DUO CCD diffractometer	2578 independent reflections
Radiation source: sealed tube	2564 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.015
ϕ and ω scans	θ_max = 62.5°, θ_min = 5.1°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −7→8
T_min = 0.829, T_max = 0.871	k = −10→10
6475 measured reflections	l = −27→27

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.074	w = 1/[σ²(F_o²) + (0.0454P)² + 0.3997P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
2578 reflections	Δρ_max = 0.22 e Å⁻³
230 parameters	Δρ_min = −0.13 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 970 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.13 (16)

Crystal data top

C₂₀H₂₈O₄	V = 1744.52 (4) Å³
M_r = 332.42	Z = 4
Orthorhombic, P2₁2₁2₁	Cu Kα radiation
a = 7.6729 (1) Å	µ = 0.70 mm⁻¹
b = 9.3972 (1) Å	T = 100 K
c = 24.1946 (3) Å	0.28 × 0.28 × 0.20 mm

Data collection top

Bruker APEXII DUO CCD diffractometer	2578 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	2564 reflections with I > 2σ(I)
T_min = 0.829, T_max = 0.871	R_int = 0.015
6475 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.074	Δρ_max = 0.22 e Å⁻³
S = 1.04	Δρ_min = −0.13 e Å⁻³
2578 reflections	Absolute structure: Flack (1983), 970 Friedel pairs
230 parameters	Absolute structure parameter: 0.13 (16)
0 restraints

Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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.

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 > 2sigma(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.39089 (14)	0.84016 (12)	0.26305 (4)	0.0253 (3)
H1O1	0.310 (3)	0.830 (3)	0.2374 (11)	0.077 (9)*
O2	1.09134 (13)	0.67838 (11)	0.21951 (4)	0.0216 (2)
O3	1.04729 (13)	0.73182 (11)	0.11546 (4)	0.0209 (2)
H1O3	1.132 (3)	0.720 (2)	0.1363 (8)	0.040 (6)*
O4	0.44447 (13)	0.73046 (14)	0.15053 (4)	0.0300 (3)
C1	0.98219 (19)	0.80709 (16)	0.32516 (6)	0.0198 (3)
H1A	1.0903	0.7775	0.3079	0.024*
H1B	0.9519	0.9001	0.3106	0.024*
C2	1.00975 (19)	0.81849 (16)	0.38772 (6)	0.0228 (3)
H2A	1.0508	0.7278	0.4018	0.027*
H2B	1.0988	0.8892	0.3952	0.027*
C3	0.8428 (2)	0.85964 (17)	0.41773 (6)	0.0233 (3)
H3A	0.8124	0.9564	0.4076	0.028*
H3B	0.8648	0.8584	0.4572	0.028*
C4	0.68635 (19)	0.76239 (16)	0.40536 (6)	0.0204 (3)
C5	0.66970 (18)	0.74674 (15)	0.34161 (5)	0.0173 (3)
H5A	0.6466	0.8435	0.3284	0.021*
C6	0.51347 (18)	0.66017 (16)	0.32182 (6)	0.0199 (3)
H6A	0.5401	0.5594	0.3239	0.024*
H6B	0.4137	0.6790	0.3453	0.024*
C7	0.47085 (18)	0.70050 (16)	0.26259 (6)	0.0200 (3)
H7A	0.3897	0.6310	0.2468	0.024*
C8	0.63225 (18)	0.70964 (15)	0.22719 (6)	0.0181 (3)
C9	0.79457 (18)	0.70681 (15)	0.24799 (5)	0.0158 (3)
C10	0.83719 (18)	0.70011 (15)	0.31011 (6)	0.0169 (3)
C11	0.93920 (17)	0.70252 (15)	0.20709 (6)	0.0171 (3)
C12	0.90331 (18)	0.72713 (15)	0.14720 (6)	0.0168 (3)
C13	0.74123 (19)	0.74250 (15)	0.12654 (6)	0.0182 (3)
C14	0.59663 (18)	0.72713 (15)	0.16633 (6)	0.0188 (3)
C15	0.70086 (18)	0.77406 (17)	0.06671 (6)	0.0211 (3)
H15A	0.5738	0.7793	0.0632	0.025*
C16	0.7741 (2)	0.91900 (17)	0.04969 (7)	0.0285 (4)
H16A	0.7297	0.9912	0.0740	0.043*
H16B	0.7397	0.9398	0.0124	0.043*
H16C	0.8990	0.9169	0.0520	0.043*
C17	0.7642 (2)	0.65721 (17)	0.02752 (6)	0.0260 (4)
H17A	0.7154	0.5675	0.0386	0.039*
H17B	0.8890	0.6519	0.0289	0.039*
H17C	0.7278	0.6789	−0.0095	0.039*
C18	0.5232 (2)	0.83806 (18)	0.42719 (6)	0.0266 (3)
H18A	0.5417	0.8660	0.4649	0.040*
H18B	0.4253	0.7746	0.4252	0.040*
H18C	0.5004	0.9209	0.4051	0.040*
C19	0.7033 (2)	0.62112 (17)	0.43667 (6)	0.0248 (3)
H19A	0.6847	0.6372	0.4754	0.037*
H19B	0.8178	0.5827	0.4310	0.037*
H19C	0.6179	0.5551	0.4231	0.037*
C20	0.8991 (2)	0.54667 (15)	0.32229 (6)	0.0202 (3)
H20A	0.9797	0.5171	0.2942	0.030*
H20B	0.8005	0.4838	0.3225	0.030*
H20C	0.9554	0.5439	0.3577	0.030*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0192 (5)	0.0318 (6)	0.0248 (5)	0.0057 (5)	−0.0006 (5)	0.0037 (5)
O2	0.0130 (5)	0.0305 (6)	0.0214 (5)	0.0023 (4)	−0.0010 (4)	−0.0002 (5)
O3	0.0147 (5)	0.0290 (6)	0.0191 (5)	0.0004 (5)	0.0017 (4)	−0.0021 (5)
O4	0.0148 (5)	0.0531 (7)	0.0221 (5)	−0.0006 (5)	−0.0031 (4)	0.0068 (5)
C1	0.0162 (7)	0.0237 (7)	0.0194 (7)	−0.0028 (6)	0.0004 (6)	−0.0023 (6)
C2	0.0203 (7)	0.0257 (7)	0.0224 (7)	−0.0049 (7)	−0.0038 (6)	−0.0034 (6)
C3	0.0261 (8)	0.0248 (8)	0.0190 (7)	0.0001 (7)	−0.0014 (7)	−0.0037 (6)
C4	0.0194 (7)	0.0250 (8)	0.0168 (7)	0.0035 (6)	0.0000 (6)	0.0000 (6)
C5	0.0167 (7)	0.0185 (7)	0.0165 (6)	0.0012 (6)	−0.0003 (6)	0.0031 (6)
C6	0.0159 (7)	0.0256 (7)	0.0183 (7)	−0.0006 (6)	0.0021 (6)	0.0016 (6)
C7	0.0142 (6)	0.0268 (7)	0.0189 (7)	−0.0002 (7)	−0.0001 (6)	0.0019 (6)
C8	0.0168 (7)	0.0183 (7)	0.0192 (7)	−0.0001 (6)	−0.0008 (6)	0.0000 (6)
C9	0.0160 (7)	0.0140 (6)	0.0173 (7)	0.0003 (6)	0.0000 (6)	0.0010 (6)
C10	0.0138 (6)	0.0193 (7)	0.0177 (6)	0.0001 (6)	−0.0003 (6)	0.0003 (6)
C11	0.0160 (7)	0.0149 (7)	0.0205 (7)	−0.0008 (6)	−0.0005 (6)	−0.0026 (5)
C12	0.0163 (7)	0.0163 (6)	0.0178 (7)	−0.0003 (6)	0.0028 (6)	−0.0030 (6)
C13	0.0176 (7)	0.0184 (7)	0.0186 (7)	−0.0004 (6)	0.0007 (6)	−0.0023 (6)
C14	0.0159 (7)	0.0207 (7)	0.0198 (7)	0.0012 (6)	−0.0017 (6)	−0.0002 (6)
C15	0.0169 (7)	0.0291 (8)	0.0174 (7)	−0.0006 (7)	−0.0012 (6)	0.0005 (6)
C16	0.0341 (9)	0.0277 (8)	0.0237 (7)	0.0022 (8)	−0.0033 (7)	0.0057 (7)
C17	0.0295 (8)	0.0317 (8)	0.0169 (7)	−0.0059 (8)	0.0004 (7)	−0.0019 (6)
C18	0.0247 (8)	0.0348 (8)	0.0204 (7)	0.0048 (7)	0.0022 (6)	0.0003 (7)
C19	0.0257 (8)	0.0315 (8)	0.0171 (7)	−0.0025 (7)	−0.0007 (7)	0.0039 (6)
C20	0.0195 (7)	0.0211 (7)	0.0199 (7)	0.0019 (6)	−0.0028 (6)	−0.0007 (6)

Geometric parameters (Å, º) top

O1—C7	1.4488 (18)	C8—C9	1.344 (2)
O1—H1O1	0.88 (3)	C8—C14	1.5066 (19)
O2—C11	1.2266 (17)	C9—C11	1.4874 (19)
O3—C12	1.3461 (17)	C9—C10	1.5394 (18)
O3—H1O3	0.83 (2)	C10—C20	1.546 (2)
O4—C14	1.2288 (18)	C11—C12	1.4931 (19)
C1—C2	1.5322 (19)	C12—C13	1.348 (2)
C1—C10	1.543 (2)	C13—C14	1.476 (2)
C1—H1A	0.9700	C13—C15	1.5098 (19)
C1—H1B	0.9700	C15—C17	1.530 (2)
C2—C3	1.522 (2)	C15—C16	1.530 (2)
C2—H2A	0.9700	C15—H15A	0.9800
C2—H2B	0.9700	C16—H16A	0.9600
C3—C4	1.538 (2)	C16—H16B	0.9600
C3—H3A	0.9700	C16—H16C	0.9600
C3—H3B	0.9700	C17—H17A	0.9600
C4—C18	1.534 (2)	C17—H17B	0.9600
C4—C19	1.534 (2)	C17—H17C	0.9600
C4—C5	1.5547 (18)	C18—H18A	0.9600
C5—C6	1.526 (2)	C18—H18B	0.9600
C5—C10	1.5570 (19)	C18—H18C	0.9600
C5—H5A	0.9800	C19—H19A	0.9600
C6—C7	1.5178 (19)	C19—H19B	0.9600
C6—H6A	0.9700	C19—H19C	0.9600
C6—H6B	0.9700	C20—H20A	0.9600
C7—C8	1.5082 (19)	C20—H20B	0.9600
C7—H7A	0.9800	C20—H20C	0.9600

C7—O1—H1O1	101.4 (19)	C1—C10—C20	109.94 (11)
C12—O3—H1O3	107.0 (14)	C9—C10—C5	106.92 (11)
C2—C1—C10	112.22 (12)	C1—C10—C5	107.24 (11)
C2—C1—H1A	109.2	C20—C10—C5	115.00 (12)
C10—C1—H1A	109.2	O2—C11—C9	123.52 (13)
C2—C1—H1B	109.2	O2—C11—C12	116.22 (13)
C10—C1—H1B	109.2	C9—C11—C12	120.26 (12)
H1A—C1—H1B	107.9	O3—C12—C13	122.83 (12)
C3—C2—C1	111.88 (12)	O3—C12—C11	114.03 (12)
C3—C2—H2A	109.2	C13—C12—C11	123.13 (12)
C1—C2—H2A	109.2	C12—C13—C14	116.18 (12)
C3—C2—H2B	109.2	C12—C13—C15	124.46 (13)
C1—C2—H2B	109.2	C14—C13—C15	119.36 (13)
H2A—C2—H2B	107.9	O4—C14—C13	120.59 (13)
C2—C3—C4	114.40 (12)	O4—C14—C8	118.62 (13)
C2—C3—H3A	108.7	C13—C14—C8	120.78 (12)
C4—C3—H3A	108.7	C13—C15—C17	112.84 (12)
C2—C3—H3B	108.7	C13—C15—C16	110.95 (12)
C4—C3—H3B	108.7	C17—C15—C16	110.82 (12)
H3A—C3—H3B	107.6	C13—C15—H15A	107.3
C18—C4—C19	107.48 (12)	C17—C15—H15A	107.3
C18—C4—C3	107.13 (12)	C16—C15—H15A	107.3
C19—C4—C3	110.61 (12)	C15—C16—H16A	109.5
C18—C4—C5	108.58 (11)	C15—C16—H16B	109.5
C19—C4—C5	114.52 (12)	H16A—C16—H16B	109.5
C3—C4—C5	108.26 (11)	C15—C16—H16C	109.5
C6—C5—C4	115.24 (11)	H16A—C16—H16C	109.5
C6—C5—C10	110.17 (11)	H16B—C16—H16C	109.5
C4—C5—C10	116.38 (11)	C15—C17—H17A	109.5
C6—C5—H5A	104.5	C15—C17—H17B	109.5
C4—C5—H5A	104.5	H17A—C17—H17B	109.5
C10—C5—H5A	104.5	C15—C17—H17C	109.5
C7—C6—C5	109.42 (12)	H17A—C17—H17C	109.5
C7—C6—H6A	109.8	H17B—C17—H17C	109.5
C5—C6—H6A	109.8	C4—C18—H18A	109.5
C7—C6—H6B	109.8	C4—C18—H18B	109.5
C5—C6—H6B	109.8	H18A—C18—H18B	109.5
H6A—C6—H6B	108.2	C4—C18—H18C	109.5
O1—C7—C8	107.49 (11)	H18A—C18—H18C	109.5
O1—C7—C6	108.07 (12)	H18B—C18—H18C	109.5
C8—C7—C6	111.93 (12)	C4—C19—H19A	109.5
O1—C7—H7A	109.8	C4—C19—H19B	109.5
C8—C7—H7A	109.8	H19A—C19—H19B	109.5
C6—C7—H7A	109.8	C4—C19—H19C	109.5
C9—C8—C14	122.44 (12)	H19A—C19—H19C	109.5
C9—C8—C7	123.18 (12)	H19B—C19—H19C	109.5
C14—C8—C7	114.35 (12)	C10—C20—H20A	109.5
C8—C9—C11	116.29 (12)	C10—C20—H20B	109.5
C8—C9—C10	124.29 (12)	H20A—C20—H20B	109.5
C11—C9—C10	119.34 (12)	C10—C20—H20C	109.5
C9—C10—C1	110.91 (11)	H20A—C20—H20C	109.5
C9—C10—C20	106.82 (12)	H20B—C20—H20C	109.5

C10—C1—C2—C3	−56.85 (16)	C2—C1—C10—C5	55.46 (15)
C1—C2—C3—C4	54.11 (17)	C6—C5—C10—C9	52.09 (15)
C2—C3—C4—C18	−166.79 (12)	C4—C5—C10—C9	−174.34 (12)
C2—C3—C4—C19	76.36 (15)	C6—C5—C10—C1	171.09 (11)
C2—C3—C4—C5	−49.87 (16)	C4—C5—C10—C1	−55.33 (16)
C18—C4—C5—C6	−60.53 (17)	C6—C5—C10—C20	−66.31 (15)
C19—C4—C5—C6	59.57 (16)	C4—C5—C10—C20	67.26 (16)
C3—C4—C5—C6	−176.51 (12)	C8—C9—C11—O2	−168.73 (14)
C18—C4—C5—C10	168.22 (12)	C10—C9—C11—O2	8.2 (2)
C19—C4—C5—C10	−71.68 (16)	C8—C9—C11—C12	10.76 (19)
C3—C4—C5—C10	52.23 (16)	C10—C9—C11—C12	−172.31 (12)
C4—C5—C6—C7	157.64 (12)	O2—C11—C12—O3	−5.63 (19)
C10—C5—C6—C7	−68.21 (14)	C9—C11—C12—O3	174.85 (12)
C5—C6—C7—O1	−73.43 (14)	O2—C11—C12—C13	174.01 (13)
C5—C6—C7—C8	44.75 (16)	C9—C11—C12—C13	−5.5 (2)
O1—C7—C8—C9	107.73 (15)	O3—C12—C13—C14	176.88 (13)
C6—C7—C8—C9	−10.8 (2)	C11—C12—C13—C14	−2.7 (2)
O1—C7—C8—C14	−70.35 (15)	O3—C12—C13—C15	−3.3 (2)
C6—C7—C8—C14	171.12 (12)	C11—C12—C13—C15	177.11 (13)
C14—C8—C9—C11	−7.9 (2)	C12—C13—C14—O4	−175.35 (15)
C7—C8—C9—C11	174.19 (13)	C15—C13—C14—O4	4.8 (2)
C14—C8—C9—C10	175.36 (13)	C12—C13—C14—C8	5.73 (19)
C7—C8—C9—C10	−2.6 (2)	C15—C13—C14—C8	−174.11 (13)
C8—C9—C10—C1	−134.70 (14)	C9—C8—C14—O4	−179.11 (15)
C11—C9—C10—C1	48.64 (17)	C7—C8—C14—O4	−1.0 (2)
C8—C9—C10—C20	105.50 (16)	C9—C8—C14—C13	−0.2 (2)
C11—C9—C10—C20	−71.16 (15)	C7—C8—C14—C13	177.93 (13)
C8—C9—C10—C5	−18.10 (19)	C12—C13—C15—C17	61.75 (19)
C11—C9—C10—C5	165.24 (11)	C14—C13—C15—C17	−118.43 (14)
C2—C1—C10—C9	171.86 (12)	C12—C13—C15—C16	−63.29 (18)
C2—C1—C10—C20	−70.22 (15)	C14—C13—C15—C16	116.53 (14)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···O2ⁱ	0.88 (2)	2.24 (3)	2.9502 (15)	137 (2)
O1—H1O1···O4	0.88 (2)	2.52 (3)	2.9399 (14)	109.8 (19)
O3—H1O3···O2	0.83 (2)	2.075 (19)	2.5892 (14)	119.8 (19)
O3—H1O3···O4ⁱⁱ	0.83 (2)	2.42 (2)	3.1635 (14)	148.8 (18)
C1—H1A···O2	0.97	2.33	2.9493 (18)	121
C5—H5A···O1	0.98	2.52	2.9933 (17)	110
C7—H7A···O2ⁱ	0.98	2.42	3.0998 (17)	126
C15—H15A···O4	0.98	2.38	2.8549 (17)	109
C16—H16C···O3	0.96	2.58	3.1654 (19)	119
C17—H17B···O3	0.96	2.53	3.1204 (18)	119
C20—H20A···O2	0.96	2.51	3.1451 (18)	124

Symmetry codes: (i) x−1, y, z; (ii) x+1, y, z.

Experimental details

Crystal data
Chemical formula	C₂₀H₂₈O₄
M_r	332.42
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	100
a, b, c (Å)	7.6729 (1), 9.3972 (1), 24.1946 (3)
V (Å³)	1744.52 (4)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.70
Crystal size (mm)	0.28 × 0.28 × 0.20

Data collection
Diffractometer	Bruker APEXII DUO CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.829, 0.871
No. of measured, independent and observed [I > 2σ(I)] reflections	6475, 2578, 2564
R_int	0.015
(sin θ/λ)_max (Å⁻¹)	0.575

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.074, 1.04
No. of reflections	2578
No. of parameters	230
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.13
Absolute structure	Flack (1983), 970 Friedel pairs
Absolute structure parameter	0.13 (16)

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O1···O2ⁱ	0.88 (2)	2.24 (3)	2.9502 (15)	137 (2)
O1—H1O1···O4	0.88 (2)	2.52 (3)	2.9399 (14)	109.8 (19)
O3—H1O3···O2	0.83 (2)	2.075 (19)	2.5892 (14)	119.8 (19)
O3—H1O3···O4ⁱⁱ	0.83 (2)	2.42 (2)	3.1635 (14)	148.8 (18)
C1—H1A···O2	0.97	2.33	2.9493 (18)	121
C5—H5A···O1	0.98	2.52	2.9933 (17)	110
C7—H7A···O2ⁱ	0.98	2.42	3.0998 (17)	126
C15—H15A···O4	0.98	2.38	2.8549 (17)	109
C16—H16C···O3	0.96	2.58	3.1654 (19)	119
C17—H17B···O3	0.96	2.53	3.1204 (18)	119
C20—H20A···O2	0.96	2.51	3.1451 (18)	124

Symmetry codes: (i) x−1, y, z; (ii) x+1, y, z.

Footnotes

‡Additional correspondence author, e-mail: suchada.c@psu.ac.th. Thomson Reuters ResearcherID: A-5085-2009.

§Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

AWS thanks the Graduate School, Prince of Songkla University, for partial financial support. The authors thank the Prince of Songkla University for financial support through the Crystal Materials Research Unit. The authors also thank Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811151.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–S19. CrossRef Web of Science Google Scholar
Batista, O., Duarte, A., Nascimento, J. M. & Simoes, F. (1994). J. Nat. Prod. 57, 858–861. CrossRef CAS PubMed Web of Science Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bunluepuech, K. & Tewtrakul, S. (2009). Songklanakarin J. Sci. Technol. 31, 289–292 Google Scholar
Chen, X., Liao, R.-A., Weng, L.-H., Xie, Q.-L. & Deng, F.-J. (2000). Jiegou Huaxue, 19, 122–125. CAS Google Scholar
Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107. CrossRef CAS Web of Science IUCr Journals Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Jonathan, L. T., Che, C. -T., Pezzuto, J. M., Fong, H. H. S. & Farnsworth, N. R. (1989). J. Nat. Prod. 59, 734–737. Google Scholar
Kabouche, A., Kabouche, Z., Öztürk, M., Kolak, U. & Topçu, G. (2007). Food Chem. 102, 1281–1287. Web of Science CrossRef CAS Google Scholar
Kupchan, S. M., Karim, A. & Marcks, C. (1968). J. Am. Chem. Soc. 90, 5923–5924. CrossRef CAS PubMed Web of Science Google Scholar
Kupchan, S. M., Karim, A. & Marcks, C. (1969). J. Org. Chem. 34, 3912–3918. CrossRef CAS PubMed Web of Science Google Scholar
Nagy, G., Günther, G., Máthé, I., Blunden, G., Yang, M.-H. & Crabb, T. A. (1999). Phytochemistry, 51, 809–812. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Ulubelen, A., Oksuz, S., Topgu, G., Goren, A. C. & Voelter, W. (2001). J. Nat. Prod. 64, 549–551. Web of Science CrossRef PubMed CAS Google Scholar