Absolute configuration of vouaca­pen-5α-ol

Fun, H.-K.; Yodsaoue, O.; Chantrapromma, S.; Karalai, C.

doi:10.1107/S1600536810029557

organic compounds

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ISSN: 2056-9890

Volume 66| Part 8| August 2010| Pages o2166-o2167

https://doi.org/10.1107/S1600536810029557

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Absolute configuration of vouacapen-5α-ol

Hoong-Kun Fun,^a ^*‡ Orapun Yodsaoue,^b Suchada Chantrapromma ^c § and Chatchanok Karalai ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bDepartment of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand, and ^cCrystal 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 22 July 2010; accepted 25 July 2010; online 31 July 2010)

The title compound, C₂₀H₃₀O₂, {systematic name: (4aR,6aS,7R,11aS,11bR)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-4a-ol}, is a cassane furanoditerpene which was isolated from the roots of Caesalpinia pulcherrima. The absolute configurations at positions 4a, 6a, 7, 11a and 11b are R, S, R, S and R, respectively. The molecule has four-fused rings consisting of three cyclohexane rings and one furan ring. The three cyclohexane rings are trans-fused. Two cyclohexane rings are in chair conformations, while the third is in an envelope conformation. In the crystal structure, the molecules are linked by intermolecular O—H⋯O hydrogen bonds into a zigzag chain along the a axis. A short O⋯O contact [3.0398 (14) Å] is also present.

Related literature

For ring conformations, see: Cremer & Pople (1975 ). For bond-length data, see: Allen et al. (1987 ). For background to cassane furanoditerpenes and their biological activities, see: Che et al. (1986 ); Jiang et al. (2001 ); McPherson et al. (1986 ); Promsawan et al. (2003 ); Ragasa et al. (2002 ); Smitinand & Larson (2001 ); Tewtrakul et al. (2003 ). For related structures, see: Fun et al. (2010 ); Jiang et al. (2001). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

C₂₀H₃₀O₂
M_r = 302.44
Orthorhombic, P 2₁ 2₁ 2₁
a = 6.7367 (2) Å
b = 12.7818 (3) Å
c = 19.3472 (5) Å
V = 1665.93 (8) Å³
Z = 4
Cu Kα radiation
μ = 0.58 mm⁻¹
T = 100 K
0.29 × 0.22 × 0.17 mm

Data collection

Bruker APEX DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.851, T_max = 0.908
30751 measured reflections
2880 independent reflections
2856 reflections with I > 2σ(I)
R_int = 0.028

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.088
S = 1.16
2880 reflections
207 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.25 e Å⁻³
Absolute structure: Flack (1983 ), 1202 Friedel pairs
Flack parameter: 0.0 (2)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H1O2⋯O1ⁱ	0.854 (19)	2.246 (19)	3.0398 (14)	154.7 (18)
Symmetry code: (i) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ .

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: https://doi.org/10.1107/S1600536810029557/is2581sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810029557/is2581Isup2.hkl

checkCIF report

Comment top

Cassane furanoditerpenes have been found from the plants in the family Caesalpiniaceae. The isolated compounds from plants in this family have been reported to show various of bioactivities such as antitumor (Che et al., 1986), antifungal (Ragasa et al., 2002), anti-tubercular (Promsawan et al., 2003), antiviral (Jiang et al., 2001) and HIV-1 protease inhibitory (Tewtrakul et al., 2003) activities. During the course of our research on bioactive compounds from natural-occuring sources, the title cassane furanoditerpene (I) which known as vouacapen-5α-ol (McPherson et al., 1986) was isolated from Caesalpinia pulcherrima (L.) Swartz, a small tree which has been used as ornamental (Smitinand & Larson, 2001), abortifacient and emmenagogue purposes. We previously reported the absolute configuration of a cassane furanoditerpene namely isovouacapenol C (Fun et al., 2010) which was isolated from the same plant. Herein the absolute configuration of another cassane furanoditerpene was determined by making use of the anomalous scattering of Cu Kα radiation with the Flack parameter being refined to 0.0 (2) and its crystal structure is reported.

The molecule of the title compound (Fig. 1) is constructed from the fusion of three cyclohexane rings and a furan ring. The three cyclohexane rings which have different conformations are trans-fused. Two cyclohexane rings A and B are in chair conformations whereas the third (ring C) adopts an envelope conformation with the puckered C8 atom having the maximum deviation of 0.3012 (14) Å from the best plane of the remaining five atoms (C9/C11–C14) and with the puckering parameters Q = 0.4287 (14) Å and θ = 49.88 (19)° and φ = 5.6 (3)° (Cremer & Pople, 1975). The furan ring (C12/C13/C15/C16/O1) is planar (rms 0.0023 (2) Å). The bond distances in (I) are within normal ranges (Allen et al., 1987) and comparable with the related structures which are caesalmin C, D, E, F and G (Jiang et al., 2001) and isovouacapenol C (Fun et al., 2010). The absolute configurations at positions 4a, 6a, 7, 11a and 11b of the vouacapen-5α-ol or atoms C5, C8, C14, C9 and C10 are R,S,R,S,R configurations.

The crystal packing of (I) is stabilized by intermolecular O—H···O hydrogen bonds (Table 1). The molecules are linked into infinite one dimensional chains along the [100] through O2—H1O2···O1 hydrogen bonds (Fig. 2 and Table 1). O···O [3.0398 (14) Å; symmetry codes -1/2+x, 3/2-y, -z and 1/2+x, 3/2-y, -z] short contacts were observed.

Related literature top

For ring conformations, see: Cremer & Pople (1975). For bond-length data, see: Allen et al. (1987). For background to cassane furanoditerpenes and their biological activity, see: Che et al. (1986); Jiang et al. (2001); McPherson et al. (1986); Promsawan et al. (2003); Ragasa et al. (2002); Smitinand & Larson (2001); Tewtrakul et al. (2003). For related structures, see: Fun et al. (2010); Jiang et al. (2001). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Experimental top

The air-dried roots of C. pulcherrima (6.3 kg) were extracted with CH₂Cl₂ (2 × 2.5 L) for 5 days at room temperature. The combined extracts were concentrated under reduced pressure to afford a dark brownish extract (75.3 g) which was further purified by quick column chromatography (QCC) over silica gel using hexane as eluent and increasing polarity with EtOAc and MeOH to afford 16 fractions (F1-F16). Fraction F2 (5.9 g) was further purified by QCC with hexane-CH₂Cl₂ (1:4), yielding the title compound as white solid (50.2 g). Colorless block-shaped single crystals of the title compound suitable for x-ray structure determination were recrystallized from CH₂Cl₂ by the slow evaporation of the solvent at room temperature after several days (m.p. 371-373 K).

Structure description top

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 and the atom-numbering scheme.
	Fig. 2. The crystal packing of (I) viewed along the b axis, showing one dimensional chains along the [100]. O—H···O hydrogen bonds are shown as dashed lines.

(4aR,6aS,7R,11aS,11bR)-4,4,7,11b- tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b- dodecahydrophenanthro[3,2-b]furan-4a-ol top

Crystal data top

C₂₀H₃₀O₂	D_x = 1.206 Mg m⁻³
M_r = 302.44	Melting point = 371–373 K
Orthorhombic, P2₁2₁2₁	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ac 2ab	Cell parameters from 2880 reflections
a = 6.7367 (2) Å	θ = 4.6–66.0°
b = 12.7818 (3) Å	µ = 0.58 mm⁻¹
c = 19.3472 (5) Å	T = 100 K
V = 1665.93 (8) Å³	Block, colorless
Z = 4	0.29 × 0.22 × 0.17 mm
F(000) = 664

Data collection top

Bruker APEX DUO CCD area-detector diffractometer	2880 independent reflections
Radiation source: sealed tube	2856 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.028
φ and ω scans	θ_max = 66.0°, θ_min = 4.6°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −7→7
T_min = 0.851, T_max = 0.908	k = −15→15
30751 measured reflections	l = −22→22

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) = 0.088	w = 1/[σ²(F_o²) + (0.0545P)² + 0.2119P] where P = (F_o² + 2F_c²)/3
S = 1.16	(Δ/σ)_max = 0.001
2880 reflections	Δρ_max = 0.21 e Å⁻³
207 parameters	Δρ_min = −0.25 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1202 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.0 (2)

Crystal data top

C₂₀H₃₀O₂	V = 1665.93 (8) Å³
M_r = 302.44	Z = 4
Orthorhombic, P2₁2₁2₁	Cu Kα radiation
a = 6.7367 (2) Å	µ = 0.58 mm⁻¹
b = 12.7818 (3) Å	T = 100 K
c = 19.3472 (5) Å	0.29 × 0.22 × 0.17 mm

Data collection top

Bruker APEX DUO CCD area-detector diffractometer	2880 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	2856 reflections with I > 2σ(I)
T_min = 0.851, T_max = 0.908	R_int = 0.028
30751 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.088	Δρ_max = 0.21 e Å⁻³
S = 1.16	Δρ_min = −0.25 e Å⁻³
2880 reflections	Absolute structure: Flack (1983), 1202 Friedel pairs
207 parameters	Absolute structure parameter: 0.0 (2)
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	1.03886 (16)	0.52792 (8)	0.07346 (5)	0.0334 (2)
O2	0.57276 (13)	0.96871 (7)	0.08320 (5)	0.0258 (2)
C1	0.9773 (2)	0.93648 (11)	0.02533 (7)	0.0275 (3)
H1A	1.0886	0.8924	0.0127	0.033*
H1B	0.8677	0.9195	−0.0052	0.033*
C2	1.0353 (2)	1.05118 (11)	0.01446 (8)	0.0328 (3)
H2A	1.1552	1.0662	0.0404	0.039*
H2B	1.0636	1.0628	−0.0341	0.039*
C3	0.8709 (2)	1.12537 (11)	0.03751 (8)	0.0304 (3)
H3A	0.7575	1.1163	0.0072	0.036*
H3B	0.9172	1.1968	0.0323	0.036*
C4	0.8027 (2)	1.10897 (11)	0.11288 (7)	0.0273 (3)
C5	0.7496 (2)	0.98994 (10)	0.12352 (7)	0.0235 (3)
C6	0.6857 (2)	0.96538 (11)	0.19790 (7)	0.0265 (3)
H6A	0.7961	0.9786	0.2289	0.032*
H6B	0.5779	1.0116	0.2109	0.032*
C7	0.6185 (2)	0.85208 (11)	0.20597 (7)	0.0264 (3)
H7A	0.4932	0.8434	0.1819	0.032*
H7B	0.5948	0.8385	0.2546	0.032*
C8	0.76551 (19)	0.77021 (11)	0.17865 (6)	0.0235 (3)
H8A	0.8849	0.7742	0.2075	0.028*
C9	0.8275 (2)	0.79830 (10)	0.10381 (6)	0.0231 (3)
H9A	0.7059	0.7988	0.0760	0.028*
C10	0.91614 (19)	0.91155 (10)	0.10034 (7)	0.0233 (3)
C11	0.9692 (2)	0.71734 (11)	0.07021 (7)	0.0295 (3)
H11A	0.9471	0.7157	0.0207	0.035*
H11B	1.1058	0.7381	0.0783	0.035*
C12	0.9355 (2)	0.61239 (11)	0.09923 (7)	0.0274 (3)
C13	0.8133 (2)	0.58241 (11)	0.15075 (7)	0.0261 (3)
C14	0.6792 (2)	0.65857 (11)	0.18679 (6)	0.0249 (3)
H14A	0.6797	0.6413	0.2362	0.030*
C15	0.8399 (2)	0.47142 (12)	0.15815 (7)	0.0316 (3)
H15A	0.7751	0.4278	0.1893	0.038*
C16	0.9764 (3)	0.44313 (11)	0.11136 (7)	0.0349 (3)
H16A	1.0227	0.3752	0.1053	0.042*
C17	0.4653 (2)	0.64563 (12)	0.16019 (7)	0.0301 (3)
H17A	0.4312	0.5727	0.1595	0.045*
H17B	0.4555	0.6738	0.1143	0.045*
H17C	0.3758	0.6824	0.1902	0.045*
C18	0.6175 (2)	1.17717 (12)	0.12459 (8)	0.0370 (4)
H18A	0.6459	1.2480	0.1113	0.056*
H18B	0.5815	1.1753	0.1726	0.056*
H18C	0.5097	1.1508	0.0972	0.056*
C19	0.9636 (3)	1.14968 (12)	0.16241 (8)	0.0376 (4)
H19A	0.9689	1.2246	0.1600	0.056*
H19B	1.0900	1.1211	0.1494	0.056*
H19C	0.9324	1.1287	0.2088	0.056*
C20	1.1033 (2)	0.91693 (12)	0.14665 (8)	0.0308 (3)
H20A	1.1679	0.8500	0.1470	0.046*
H20B	1.0654	0.9354	0.1929	0.046*
H20C	1.1928	0.9688	0.1288	0.046*
H1O2	0.602 (3)	0.9757 (14)	0.0405 (10)	0.038 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0389 (6)	0.0318 (5)	0.0295 (5)	0.0068 (5)	0.0075 (4)	0.0007 (4)
O2	0.0193 (5)	0.0341 (5)	0.0239 (5)	−0.0007 (4)	−0.0017 (4)	0.0012 (4)
C1	0.0247 (7)	0.0333 (7)	0.0245 (7)	−0.0005 (6)	0.0057 (5)	0.0007 (5)
C2	0.0313 (8)	0.0389 (8)	0.0283 (7)	−0.0058 (6)	0.0075 (6)	0.0034 (6)
C3	0.0345 (8)	0.0288 (7)	0.0278 (7)	−0.0061 (6)	0.0020 (6)	0.0016 (5)
C4	0.0290 (7)	0.0296 (7)	0.0232 (7)	−0.0039 (6)	0.0000 (6)	−0.0007 (5)
C5	0.0192 (6)	0.0302 (7)	0.0212 (6)	−0.0002 (5)	0.0002 (5)	0.0000 (5)
C6	0.0258 (6)	0.0328 (7)	0.0210 (6)	0.0017 (6)	0.0025 (5)	−0.0028 (5)
C7	0.0242 (6)	0.0342 (7)	0.0207 (6)	0.0013 (6)	0.0058 (5)	0.0015 (5)
C8	0.0195 (6)	0.0324 (7)	0.0184 (6)	0.0010 (6)	−0.0001 (5)	0.0016 (5)
C9	0.0192 (6)	0.0306 (7)	0.0196 (6)	0.0015 (5)	0.0015 (5)	0.0009 (5)
C10	0.0184 (6)	0.0299 (7)	0.0216 (6)	−0.0009 (5)	0.0005 (5)	0.0004 (5)
C11	0.0285 (7)	0.0334 (7)	0.0267 (7)	0.0032 (6)	0.0075 (6)	0.0019 (6)
C12	0.0284 (7)	0.0314 (7)	0.0224 (7)	0.0064 (6)	0.0001 (5)	−0.0029 (5)
C13	0.0265 (7)	0.0306 (7)	0.0213 (6)	−0.0006 (5)	−0.0032 (5)	0.0011 (5)
C14	0.0248 (6)	0.0330 (7)	0.0169 (6)	−0.0005 (6)	0.0019 (5)	0.0020 (5)
C15	0.0380 (8)	0.0323 (7)	0.0244 (7)	−0.0020 (7)	−0.0005 (6)	0.0029 (6)
C16	0.0480 (9)	0.0277 (7)	0.0290 (7)	0.0059 (7)	0.0004 (7)	0.0022 (6)
C17	0.0267 (7)	0.0376 (7)	0.0260 (7)	−0.0036 (6)	0.0012 (6)	0.0025 (6)
C18	0.0438 (9)	0.0311 (7)	0.0363 (8)	0.0042 (7)	0.0063 (7)	−0.0006 (6)
C19	0.0437 (9)	0.0375 (8)	0.0315 (8)	−0.0123 (7)	−0.0046 (7)	−0.0035 (6)
C20	0.0191 (6)	0.0412 (8)	0.0321 (7)	−0.0023 (6)	−0.0034 (6)	0.0025 (6)

Geometric parameters (Å, º) top

O1—C16	1.3745 (17)	C9—C11	1.5507 (18)
O1—C12	1.3780 (16)	C9—C10	1.5673 (18)
O2—C5	1.4494 (16)	C9—H9A	0.9800
O2—H1O2	0.85 (2)	C10—C20	1.5486 (18)
C1—C2	1.5319 (19)	C11—C12	1.4719 (19)
C1—C10	1.5417 (18)	C11—H11A	0.9700
C1—H1A	0.9700	C11—H11B	0.9700
C1—H1B	0.9700	C12—C13	1.348 (2)
C2—C3	1.525 (2)	C13—C15	1.437 (2)
C2—H2A	0.9700	C13—C14	1.5001 (19)
C2—H2B	0.9700	C14—C17	1.5388 (19)
C3—C4	1.5432 (19)	C14—H14A	0.9800
C3—H3A	0.9700	C15—C16	1.340 (2)
C3—H3B	0.9700	C15—H15A	0.9300
C4—C19	1.538 (2)	C16—H16A	0.9300
C4—C18	1.538 (2)	C17—H17A	0.9600
C4—C5	1.5764 (19)	C17—H17B	0.9600
C5—C6	1.5345 (18)	C17—H17C	0.9600
C5—C10	1.5699 (18)	C18—H18A	0.9600
C6—C7	1.525 (2)	C18—H18B	0.9600
C6—H6A	0.9700	C18—H18C	0.9600
C6—H6B	0.9700	C19—H19A	0.9600
C7—C8	1.5347 (18)	C19—H19B	0.9600
C7—H7A	0.9700	C19—H19C	0.9600
C7—H7B	0.9700	C20—H20A	0.9600
C8—C14	1.5489 (19)	C20—H20B	0.9600
C8—C9	1.5493 (17)	C20—H20C	0.9600
C8—H8A	0.9800

C16—O1—C12	105.67 (11)	C10—C9—H9A	106.8
C5—O2—H1O2	108.0 (13)	C1—C10—C20	108.54 (11)
C2—C1—C10	113.28 (11)	C1—C10—C9	109.45 (10)
C2—C1—H1A	108.9	C20—C10—C9	109.06 (11)
C10—C1—H1A	108.9	C1—C10—C5	109.14 (10)
C2—C1—H1B	108.9	C20—C10—C5	112.86 (11)
C10—C1—H1B	108.9	C9—C10—C5	107.75 (10)
H1A—C1—H1B	107.7	C12—C11—C9	110.69 (11)
C3—C2—C1	111.68 (11)	C12—C11—H11A	109.5
C3—C2—H2A	109.3	C9—C11—H11A	109.5
C1—C2—H2A	109.3	C12—C11—H11B	109.5
C3—C2—H2B	109.3	C9—C11—H11B	109.5
C1—C2—H2B	109.3	H11A—C11—H11B	108.1
H2A—C2—H2B	107.9	C13—C12—O1	110.69 (12)
C2—C3—C4	114.09 (12)	C13—C12—C11	129.43 (12)
C2—C3—H3A	108.7	O1—C12—C11	119.88 (12)
C4—C3—H3A	108.7	C12—C13—C15	106.14 (13)
C2—C3—H3B	108.7	C12—C13—C14	121.80 (12)
C4—C3—H3B	108.7	C15—C13—C14	132.02 (13)
H3A—C3—H3B	107.6	C13—C14—C17	109.80 (11)
C19—C4—C18	106.74 (12)	C13—C14—C8	108.93 (11)
C19—C4—C3	109.45 (12)	C17—C14—C8	114.61 (11)
C18—C4—C3	107.68 (12)	C13—C14—H14A	107.8
C19—C4—C5	113.90 (11)	C17—C14—H14A	107.8
C18—C4—C5	110.10 (11)	C8—C14—H14A	107.8
C3—C4—C5	108.79 (11)	C16—C15—C13	106.54 (13)
O2—C5—C6	103.66 (10)	C16—C15—H15A	126.7
O2—C5—C10	108.31 (10)	C13—C15—H15A	126.7
C6—C5—C10	109.74 (10)	C15—C16—O1	110.95 (13)
O2—C5—C4	107.27 (10)	C15—C16—H16A	124.5
C6—C5—C4	112.55 (11)	O1—C16—H16A	124.5
C10—C5—C4	114.61 (10)	C14—C17—H17A	109.5
C7—C6—C5	111.92 (11)	C14—C17—H17B	109.5
C7—C6—H6A	109.2	H17A—C17—H17B	109.5
C5—C6—H6A	109.2	C14—C17—H17C	109.5
C7—C6—H6B	109.2	H17A—C17—H17C	109.5
C5—C6—H6B	109.2	H17B—C17—H17C	109.5
H6A—C6—H6B	107.9	C4—C18—H18A	109.5
C6—C7—C8	114.87 (11)	C4—C18—H18B	109.5
C6—C7—H7A	108.5	H18A—C18—H18B	109.5
C8—C7—H7A	108.5	C4—C18—H18C	109.5
C6—C7—H7B	108.5	H18A—C18—H18C	109.5
C8—C7—H7B	108.5	H18B—C18—H18C	109.5
H7A—C7—H7B	107.5	C4—C19—H19A	109.5
C7—C8—C14	110.54 (11)	C4—C19—H19B	109.5
C7—C8—C9	109.74 (11)	H19A—C19—H19B	109.5
C14—C8—C9	114.19 (11)	C4—C19—H19C	109.5
C7—C8—H8A	107.4	H19A—C19—H19C	109.5
C14—C8—H8A	107.4	H19B—C19—H19C	109.5
C9—C8—H8A	107.4	C10—C20—H20A	109.5
C8—C9—C11	113.77 (11)	C10—C20—H20B	109.5
C8—C9—C10	110.90 (10)	H20A—C20—H20B	109.5
C11—C9—C10	111.33 (10)	C10—C20—H20C	109.5
C8—C9—H9A	106.8	H20A—C20—H20C	109.5
C11—C9—H9A	106.8	H20B—C20—H20C	109.5

C10—C1—C2—C3	−55.24 (17)	C11—C9—C10—C5	170.45 (11)
C1—C2—C3—C4	55.00 (16)	O2—C5—C10—C1	66.93 (13)
C2—C3—C4—C19	72.73 (15)	C6—C5—C10—C1	179.45 (11)
C2—C3—C4—C18	−171.60 (12)	C4—C5—C10—C1	−52.77 (14)
C2—C3—C4—C5	−52.30 (15)	O2—C5—C10—C20	−172.30 (10)
C19—C4—C5—O2	169.30 (11)	C6—C5—C10—C20	−59.78 (14)
C18—C4—C5—O2	49.46 (14)	C4—C5—C10—C20	68.00 (14)
C3—C4—C5—O2	−68.32 (13)	O2—C5—C10—C9	−51.83 (13)
C19—C4—C5—C6	55.92 (15)	C6—C5—C10—C9	60.69 (13)
C18—C4—C5—C6	−63.92 (15)	C4—C5—C10—C9	−171.54 (10)
C3—C4—C5—C6	178.30 (11)	C8—C9—C11—C12	28.58 (16)
C19—C4—C5—C10	−70.41 (15)	C10—C9—C11—C12	154.78 (11)
C18—C4—C5—C10	169.75 (11)	C16—O1—C12—C13	−0.18 (16)
C3—C4—C5—C10	51.97 (14)	C16—O1—C12—C11	179.32 (13)
O2—C5—C6—C7	59.70 (13)	C9—C11—C12—C13	−4.3 (2)
C10—C5—C6—C7	−55.82 (14)	C9—C11—C12—O1	176.33 (12)
C4—C5—C6—C7	175.28 (11)	O1—C12—C13—C15	−0.23 (16)
C5—C6—C7—C8	51.72 (15)	C11—C12—C13—C15	−179.67 (15)
C6—C7—C8—C14	−177.79 (11)	O1—C12—C13—C14	−178.36 (11)
C6—C7—C8—C9	−50.97 (15)	C11—C12—C13—C14	2.2 (2)
C7—C8—C9—C11	−177.42 (11)	C12—C13—C14—C17	102.74 (15)
C14—C8—C9—C11	−52.68 (15)	C15—C13—C14—C17	−74.84 (18)
C7—C8—C9—C10	56.15 (14)	C12—C13—C14—C8	−23.52 (17)
C14—C8—C9—C10	−179.10 (10)	C15—C13—C14—C8	158.90 (14)
C2—C1—C10—C20	−70.08 (15)	C7—C8—C14—C13	172.14 (10)
C2—C1—C10—C9	171.00 (11)	C9—C8—C14—C13	47.82 (14)
C2—C1—C10—C5	53.30 (15)	C7—C8—C14—C17	48.70 (14)
C8—C9—C10—C1	179.65 (11)	C9—C8—C14—C17	−75.62 (14)
C11—C9—C10—C1	51.88 (14)	C12—C13—C15—C16	0.56 (17)
C8—C9—C10—C20	61.04 (13)	C14—C13—C15—C16	178.42 (14)
C11—C9—C10—C20	−66.72 (13)	C13—C15—C16—O1	−0.70 (17)
C8—C9—C10—C5	−61.79 (13)	C12—O1—C16—C15	0.56 (17)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1O2···O1ⁱ	0.854 (19)	2.246 (19)	3.0398 (14)	154.7 (18)

Symmetry code: (i) x−1/2, −y+3/2, −z.

Experimental details

Crystal data
Chemical formula	C₂₀H₃₀O₂
M_r	302.44
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	100
a, b, c (Å)	6.7367 (2), 12.7818 (3), 19.3472 (5)
V (Å³)	1665.93 (8)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.58
Crystal size (mm)	0.29 × 0.22 × 0.17

Data collection
Diffractometer	Bruker APEX DUO CCD area-detector
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.851, 0.908
No. of measured, independent and observed [I > 2σ(I)] reflections	30751, 2880, 2856
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.592

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.088, 1.16
No. of reflections	2880
No. of parameters	207
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.25
Absolute structure	Flack (1983), 1202 Friedel pairs
Absolute structure parameter	0.0 (2)

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
O2—H1O2···O1ⁱ	0.854 (19)	2.246 (19)	3.0398 (14)	154.7 (18)

Symmetry code: (i) x−1/2, −y+3/2, −z.

Footnotes

‡Thomson Reuters ResearcherID: A-3561-2009.

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

Acknowledgements

OY thanks the Office of the Higher Education Commission, Thailand, for financial support by a grant fund under the program "Strategic Scholarships for Frontier Research Network for the Joint PhD Program Thai Doctoral Degree". The authors thank the Thailand Research Fund (BRG5280013) and Prince of Songkla University for financial support. The authors also thank Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

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