(4bS,8aS)-1-Isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa­hydro­phenan­thren-2-yl acetate

Oubabi, R.; Auhmani, A.; Ait Itto, M.Y.; Auhmani, A.; Daran, J.-C.

doi:10.1107/S1600536814002748

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 3| March 2014| Page o317

doi:10.1107/S1600536814002748

Open

access

(4bS,8aS)-1-Isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthren-2-yl acetate

Radouane Oubabi,^a Aziz Auhmani,^a My Youssef Ait Itto,^a ^* Abdelwahed Auhmani ^a and Jean-Claude Daran ^b

^aLaboratoire de Synthése Organique et Physico-Chimie Moléculaire, Département de Chimie, Faculté des Sciences, Semlalia, BP 2390, Marrakech 40000, Morocco, and ^bLaboratoire de Chimie de Coordination, 205 route de Narbonne, 31077 Toulouse Cedex 04, France
^*Correspondence e-mail: itto35@hotmail.com

(Received 29 January 2014; accepted 5 February 2014; online 19 February 2014)

The hemisynthesis of the title compound, C₂₂H₃₂O₂, was carried out through direct acetylation reaction of the naturally occurring diterpene totarol [systematic name: (4bS,8aS)-4b,8,8-trimethyl-1-propan-2-yl-5,6,7,8a,9,10-hexahydrophenanthren-2-ol]. The molecule is built up from three fused six membered rings, one saturated and two unsaturated. The central unsaturated ring has a half-chair conformation, whereas the other unsaturated ring displays a chair conformation. The absolute configuration is deduced from the chemical pathway. The value of the Hooft parameter [−0.10 (6)] allowed this absolute configuration to be confirmed.

CCDC reference:

Related literature

For the synthesis, see: Short & Stromberg (1937 ). For biological properties of totarol, see: Barrero et al. (2003 ); Bernabeu et al. (2002 ); Haraguchi et al. (1996 ); Marcos et al. (2003 ); Tacon et al. (2012 ). For related structures, see: Zeroual et al. (2008 ); Pettit et al. (2004 ). For structural discussion, see: Cremer & Pople (1975 ); Flack (1983 ); Flack & Bernardinelli (2000 ); Spek (2009 ).

Experimental

Crystal data

C₂₂H₃₂O₂
M_r = 328.47
Monoclinic, P 2₁
a = 7.4250 (2) Å
b = 10.5716 (3) Å
c = 12.0747 (3) Å
β = 90.124 (2)°
V = 947.79 (4) Å³
Z = 2
Cu Kα radiation
μ = 0.55 mm⁻¹
T = 180 K
0.38 × 0.38 × 0.14 mm

Data collection

Agilent Xcalibur (Eos, Gemini ultra) diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012) T_min = 0.860, T_max = 1.000
4370 measured reflections
2511 independent reflections
2490 reflections with I > 2σ(I)
R_int = 0.012
θ_max = 60.7°

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.075
S = 1.04
2511 reflections
225 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.14 e Å⁻³
Absolute structure: Refined as an inversion twin.
Absolute structure parameter: 0.0 (3)

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008 ); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ) ORTEP-3 for Windows (Farrugia, 2012 ); software used to prepare material for publication: SHELXL2013.

Supporting information

CCDC reference:

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S1600536814002748/xu5767sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814002748/xu5767Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814002748/xu5767Isup3.cml

checkCIF report

Comment top

The hemisynthesis of the title compound C₂₂H₃₂O₂ 2 was carried out through direct acetylation reaction of naturally occurred Totarol (1). Totarol (1) is a naturally produced diterpene isolated from a several plants such as Podocarpus totara (Short & Stromberg, 1937) Tetraclinis articulata (Barrero et al., 2003). It has been attracting great interest because of its biological properties ranging from Antimicrobial (Haraguchi et al., 1996), anti-oxidant (Bernabeu et al., 2002), Anti-inflammatory, analgesic, anti-tumoral (Marcos et al., 2003) to Anti-plasmodial (Tacon et al., 2012).

In the aim of preparing totarol derivatives, we report here, the hemisynthesis of (4bS,8aS)-1-isopropyl-4 b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthren-2-yl acetate 2 from naturally occurred Totarol (1). Thus, treatment of (1) with acetic anhydride in pyridine provides (2) as colorless crystals in 97% yield. Its structure was fully characterized by its mass and NMR spectroscopic data. Furthermore, an X-ray single-crystal structure analysis allowed us to confirm unambiguously its full structure.

Compound (2) is built up from three fused six membered rings, a saturated one and two unsaturated (Fig. 1). The central unsaturated ring has an half chair conformation with puckering parameters: Q = 0.531 (2) Å, θ= 50.4 (2)° and φ= 120.1 (4)° (Cremer & Pople, 1975), whereas the second insaturated six-membered ring displays a chair conformation with puckering parameters: Q = 0.535 (3) Å, θ= 173.2 (3) (2)° and φ= 289 (2)°. Similar conformation for the three fused rings has been reported previously with hydroxyl substituent in place of the acetate in the title compound (Zeroual et al., 2008) and with either an hydroxyl or a methoxy substituent on the central ring (Pettit et al., 2004).

The absolute configuration (4S,8S) deduced from the chemical pathway is supported by the refinement of the Flack parameter, 0.0 (3), (Flack, 1983; Flack & Bernardinelli, 2000) and confirmed by the refinement of the Hooft parameter, -0.10 (6) (Spek, 2009).

Related literature top

For the synthesis, see: Short & Stromberg (1937). For biological properties of totarol, see: Barrero et al. (2003); Bernabeu et al. (2002); Haraguchi et al. (1996); Marcos et al. (2003); Tacon et al. (2012). For related structures, see: Zeroual et al. (2008); Pettit et al. (2004). For structural discussion, see: Cremer & Pople (1975); Flack (1983); Flack & Bernardinelli (2000); Spek (2009).

Experimental top

A solution of totarol (1) (90 mg, 0.314 mmol) in acetic anhydride (20 ml) and pyridine (20 ml) was heated under reflux for 24 h. After cooling, the mixture was acidified with 1N HCl solution then extracted with ether (3 × 20 ml). The organic layer was washed with water, dried on anhydrous Na₂SO₄ and then evaporated under reduced pressure. The obtained residue was chromatographied on silica gel column using hexane and ethyl acetate (97/3) as eluent, to give (4bS,8aS)-1-isopropyl-4 b,8,8-trimethyl-4 b,5,6,7,8,8a,9,10-octahydrophenanthren-2-yl acetate (2) (100 mg) in 97% yield.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL2013 (Sheldrick, 2008).

Figures top

Fig. 1. : Molecular view of compound (2) with the atom labeling scheme. Ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.

(4bS,8aS)-1-Isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthren-2-yl acetate top

Crystal data top

C₂₂H₃₂O₂	F(000) = 360
M_r = 328.47	D_x = 1.151 Mg m⁻³
Monoclinic, P2₁	Cu Kα radiation, λ = 1.54184 Å
a = 7.4250 (2) Å	Cell parameters from 3311 reflections
b = 10.5716 (3) Å	θ = 3.7–60.6°
c = 12.0747 (3) Å	µ = 0.55 mm⁻¹
β = 90.124 (2)°	T = 180 K
V = 947.79 (4) Å³	Box, colourless
Z = 2	0.38 × 0.38 × 0.14 mm

Data collection top

Agilent Xcalibur (Eos, Gemini ultra) diffractometer	2511 independent reflections
Radiation source: Enhance Ultra (Cu) X-ray Source	2490 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.012
Detector resolution: 16.1978 pixels mm^-1	θ_max = 60.7°, θ_min = 3.7°
ω scans	h = −7→8
Absorption correction: multi-scan Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm (CrysAlis PRO, Agilent, 2012)	k = −11→11
T_min = 0.860, T_max = 1.000	l = −13→13
4370 measured reflections

Refinement top

Refinement on F²	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0433P)² + 0.168P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.029	(Δ/σ)_max < 0.001
wR(F²) = 0.075	Δρ_max = 0.13 e Å⁻³
S = 1.04	Δρ_min = −0.14 e Å⁻³
2511 reflections	Extinction correction: SHELXL2013 (Sheldrick, 2013), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
225 parameters	Extinction coefficient: 0.050 (2)
1 restraint	Absolute structure: Refined as an inversion twin.
Hydrogen site location: inferred from neighbouring sites	Absolute structure parameter: 0.0 (3)

Crystal data top

C₂₂H₃₂O₂	V = 947.79 (4) Å³
M_r = 328.47	Z = 2
Monoclinic, P2₁	Cu Kα radiation
a = 7.4250 (2) Å	µ = 0.55 mm⁻¹
b = 10.5716 (3) Å	T = 180 K
c = 12.0747 (3) Å	0.38 × 0.38 × 0.14 mm
β = 90.124 (2)°

Data collection top

Agilent Xcalibur (Eos, Gemini ultra) diffractometer	2511 independent reflections
Absorption correction: multi-scan Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm (CrysAlis PRO, Agilent, 2012)	2490 reflections with I > 2σ(I)
T_min = 0.860, T_max = 1.000	R_int = 0.012
4370 measured reflections	θ_max = 60.7°

Refinement top

R[F² > 2σ(F²)] = 0.029	H-atom parameters constrained
wR(F²) = 0.075	Δρ_max = 0.13 e Å⁻³
S = 1.04	Δρ_min = −0.14 e Å⁻³
2511 reflections	Absolute structure: Refined as an inversion twin.
225 parameters	Absolute structure parameter: 0.0 (3)
1 restraint

Special details top

Experimental. Absorption correction: Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm (CrysAlis PRO; Agilent Technologies, 2012)

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refined as a 2-component inversion twin.

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

	x	y	z	U_iso*/U_eq
C1	0.6487 (3)	0.6992 (2)	0.17276 (16)	0.0270 (5)
C2	0.4780 (3)	0.7203 (2)	0.13012 (17)	0.0283 (5)
C3	0.3461 (3)	0.7823 (2)	0.18816 (19)	0.0334 (5)
H3	0.2304	0.7948	0.1562	0.040*
C4	0.3833 (3)	0.8262 (2)	0.29347 (18)	0.0319 (5)
H4	0.2916	0.8682	0.3341	0.038*
C4A	0.5533 (3)	0.81000 (19)	0.34131 (17)	0.0244 (5)
C4B	0.5942 (3)	0.8675 (2)	0.45589 (18)	0.0258 (5)
C5	0.4239 (3)	0.8711 (3)	0.52884 (19)	0.0346 (6)
H5A	0.3376	0.9327	0.4972	0.041*
H5B	0.3659	0.7868	0.5276	0.041*
C6	0.4646 (3)	0.9074 (3)	0.6486 (2)	0.0406 (6)
H6A	0.5144	0.9942	0.6509	0.049*
H6B	0.3515	0.9067	0.6919	0.049*
C7	0.5980 (3)	0.8167 (3)	0.70024 (18)	0.0371 (6)
H7A	0.5427	0.7315	0.7033	0.045*
H7B	0.6222	0.8438	0.7773	0.045*
C8	0.7773 (3)	0.8075 (2)	0.63830 (18)	0.0338 (5)
C8A	0.7386 (3)	0.7834 (2)	0.51303 (17)	0.0275 (5)
H8A	0.6896	0.6954	0.5093	0.033*
C9	0.9073 (3)	0.7813 (3)	0.44192 (19)	0.0372 (6)
H9A	0.9521	0.8687	0.4322	0.045*
H9B	1.0022	0.7319	0.4801	0.045*
C10	0.8707 (3)	0.7233 (3)	0.32926 (18)	0.0366 (6)
H10A	0.9617	0.7561	0.2768	0.044*
H10B	0.8890	0.6307	0.3351	0.044*
C10A	0.6862 (3)	0.74630 (19)	0.28005 (17)	0.0261 (5)
C11	0.7945 (3)	0.6336 (2)	0.10479 (18)	0.0343 (6)
H11	0.8978	0.6181	0.1562	0.041*
C12	0.7413 (4)	0.5048 (3)	0.0572 (2)	0.0540 (8)
H12A	0.8501	0.4562	0.0400	0.081*
H12B	0.6704	0.5170	−0.0105	0.081*
H12C	0.6691	0.4585	0.1117	0.081*
C13	0.8634 (4)	0.7225 (3)	0.0150 (2)	0.0518 (7)
H13A	0.9103	0.7998	0.0492	0.078*
H13B	0.7644	0.7440	−0.0355	0.078*
H13C	0.9597	0.6807	−0.0266	0.078*
C14	0.6541 (4)	1.0050 (2)	0.4337 (2)	0.0433 (6)
H14A	0.5590	1.0497	0.3933	0.065*
H14B	0.7647	1.0047	0.3895	0.065*
H14C	0.6768	1.0478	0.5044	0.065*
C15	0.8902 (4)	0.9257 (3)	0.6616 (2)	0.0489 (7)
H15A	0.9251	0.9270	0.7399	0.073*
H15B	0.8193	1.0013	0.6444	0.073*
H15C	0.9986	0.9243	0.6154	0.073*
C16	0.8803 (4)	0.6933 (3)	0.6843 (2)	0.0561 (8)
H16A	0.8152	0.6154	0.6657	0.084*
H16B	0.8905	0.7008	0.7649	0.084*
H16C	1.0009	0.6905	0.6516	0.084*
C17	0.3222 (3)	0.5899 (2)	0.00169 (19)	0.0345 (6)
C18	0.3010 (4)	0.5659 (3)	−0.1197 (2)	0.0460 (7)
H18A	0.1878	0.5206	−0.1331	0.069*
H18B	0.4021	0.5146	−0.1461	0.069*
H18C	0.2991	0.6467	−0.1594	0.069*
O1	0.4419 (2)	0.68523 (16)	0.01943 (11)	0.0338 (4)
O2	0.2470 (2)	0.53449 (19)	0.07423 (14)	0.0491 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0302 (12)	0.0261 (11)	0.0248 (11)	0.0012 (10)	0.0028 (9)	0.0023 (9)
C2	0.0305 (12)	0.0316 (12)	0.0230 (10)	−0.0026 (10)	0.0004 (9)	0.0014 (9)
C3	0.0244 (12)	0.0444 (13)	0.0315 (12)	0.0021 (11)	−0.0022 (9)	0.0002 (10)
C4	0.0269 (12)	0.0355 (12)	0.0333 (12)	0.0060 (10)	0.0031 (9)	−0.0010 (10)
C4A	0.0256 (11)	0.0205 (10)	0.0271 (11)	0.0010 (9)	0.0026 (8)	0.0024 (9)
C4B	0.0262 (11)	0.0221 (10)	0.0290 (11)	0.0006 (9)	0.0022 (9)	−0.0022 (9)
C5	0.0302 (12)	0.0422 (13)	0.0314 (12)	0.0063 (11)	0.0022 (10)	−0.0072 (10)
C6	0.0327 (13)	0.0533 (17)	0.0357 (13)	0.0027 (12)	0.0065 (10)	−0.0129 (12)
C7	0.0413 (14)	0.0448 (14)	0.0253 (11)	−0.0082 (12)	0.0023 (10)	−0.0068 (11)
C8	0.0342 (12)	0.0386 (13)	0.0286 (11)	0.0002 (11)	−0.0037 (9)	−0.0071 (10)
C8A	0.0269 (11)	0.0271 (11)	0.0286 (11)	−0.0019 (10)	−0.0001 (9)	−0.0041 (9)
C9	0.0276 (12)	0.0497 (14)	0.0343 (13)	0.0040 (11)	−0.0011 (9)	−0.0077 (11)
C10	0.0280 (12)	0.0513 (15)	0.0305 (12)	0.0089 (11)	0.0005 (10)	−0.0047 (11)
C10A	0.0261 (11)	0.0259 (11)	0.0263 (11)	0.0000 (9)	0.0031 (9)	0.0028 (9)
C11	0.0322 (12)	0.0457 (14)	0.0251 (11)	0.0109 (11)	0.0018 (9)	−0.0012 (10)
C12	0.0587 (19)	0.0487 (17)	0.0546 (17)	0.0163 (14)	0.0060 (14)	−0.0166 (13)
C13	0.0399 (15)	0.0696 (19)	0.0460 (15)	0.0121 (14)	0.0175 (12)	0.0119 (14)
C14	0.0599 (17)	0.0281 (13)	0.0421 (14)	−0.0045 (12)	−0.0035 (12)	0.0017 (11)
C15	0.0363 (14)	0.0662 (18)	0.0441 (15)	−0.0116 (13)	−0.0023 (11)	−0.0189 (14)
C16	0.068 (2)	0.0664 (18)	0.0338 (13)	0.0231 (17)	−0.0133 (13)	−0.0045 (14)
C17	0.0352 (13)	0.0364 (13)	0.0319 (12)	0.0016 (11)	−0.0017 (10)	−0.0013 (10)
C18	0.0489 (16)	0.0560 (17)	0.0332 (13)	−0.0039 (13)	−0.0023 (11)	−0.0089 (12)
O1	0.0341 (9)	0.0432 (9)	0.0239 (8)	−0.0036 (8)	−0.0002 (6)	−0.0011 (7)
O2	0.0587 (12)	0.0514 (11)	0.0372 (9)	−0.0160 (10)	0.0039 (9)	−0.0001 (9)

Geometric parameters (Å, º) top

C1—C2	1.385 (3)	C9—H9A	0.9900
C1—C10A	1.415 (3)	C9—H9B	0.9900
C1—C11	1.526 (3)	C10—C10A	1.512 (3)
C2—C3	1.372 (3)	C10—H10A	0.9900
C2—O1	1.412 (3)	C10—H10B	0.9900
C3—C4	1.381 (3)	C11—C13	1.524 (4)
C3—H3	0.9500	C11—C12	1.530 (4)
C4—C4A	1.398 (3)	C11—H11	1.0000
C4—H4	0.9500	C12—H12A	0.9800
C4A—C10A	1.406 (3)	C12—H12B	0.9800
C4A—C4B	1.541 (3)	C12—H12C	0.9800
C4B—C5	1.543 (3)	C13—H13A	0.9800
C4B—C14	1.544 (3)	C13—H13B	0.9800
C4B—C8A	1.553 (3)	C13—H13C	0.9800
C5—C6	1.526 (3)	C14—H14A	0.9800
C5—H5A	0.9900	C14—H14B	0.9800
C5—H5B	0.9900	C14—H14C	0.9800
C6—C7	1.512 (4)	C15—H15A	0.9800
C6—H6A	0.9900	C15—H15B	0.9800
C6—H6B	0.9900	C15—H15C	0.9800
C7—C8	1.532 (3)	C16—H16A	0.9800
C7—H7A	0.9900	C16—H16B	0.9800
C7—H7B	0.9900	C16—H16C	0.9800
C8—C15	1.530 (4)	C17—O2	1.193 (3)
C8—C16	1.533 (4)	C17—O1	1.361 (3)
C8—C8A	1.560 (3)	C17—C18	1.496 (3)
C8A—C9	1.520 (3)	C18—H18A	0.9800
C8A—H8A	1.0000	C18—H18B	0.9800
C9—C10	1.516 (3)	C18—H18C	0.9800

C2—C1—C10A	117.49 (18)	H9A—C9—H9B	108.0
C2—C1—C11	121.51 (18)	C10A—C10—C9	116.61 (19)
C10A—C1—C11	120.92 (19)	C10A—C10—H10A	108.1
C3—C2—C1	122.74 (18)	C9—C10—H10A	108.1
C3—C2—O1	118.32 (18)	C10A—C10—H10B	108.1
C1—C2—O1	118.77 (18)	C9—C10—H10B	108.1
C2—C3—C4	119.29 (19)	H10A—C10—H10B	107.3
C2—C3—H3	120.4	C4A—C10A—C1	120.89 (19)
C4—C3—H3	120.4	C4A—C10A—C10	120.43 (18)
C3—C4—C4A	121.18 (19)	C1—C10A—C10	118.65 (18)
C3—C4—H4	119.4	C13—C11—C1	110.0 (2)
C4A—C4—H4	119.4	C13—C11—C12	111.6 (2)
C4—C4A—C10A	118.38 (18)	C1—C11—C12	115.1 (2)
C4—C4A—C4B	119.92 (18)	C13—C11—H11	106.5
C10A—C4A—C4B	121.63 (18)	C1—C11—H11	106.5
C4A—C4B—C5	111.23 (17)	C12—C11—H11	106.5
C4A—C4B—C14	105.79 (18)	C11—C12—H12A	109.5
C5—C4B—C14	108.22 (19)	C11—C12—H12B	109.5
C4A—C4B—C8A	107.92 (17)	H12A—C12—H12B	109.5
C5—C4B—C8A	109.04 (17)	C11—C12—H12C	109.5
C14—C4B—C8A	114.6 (2)	H12A—C12—H12C	109.5
C6—C5—C4B	112.74 (18)	H12B—C12—H12C	109.5
C6—C5—H5A	109.0	C11—C13—H13A	109.5
C4B—C5—H5A	109.0	C11—C13—H13B	109.5
C6—C5—H5B	109.0	H13A—C13—H13B	109.5
C4B—C5—H5B	109.0	C11—C13—H13C	109.5
H5A—C5—H5B	107.8	H13A—C13—H13C	109.5
C7—C6—C5	111.0 (2)	H13B—C13—H13C	109.5
C7—C6—H6A	109.4	C4B—C14—H14A	109.5
C5—C6—H6A	109.4	C4B—C14—H14B	109.5
C7—C6—H6B	109.4	H14A—C14—H14B	109.5
C5—C6—H6B	109.4	C4B—C14—H14C	109.5
H6A—C6—H6B	108.0	H14A—C14—H14C	109.5
C6—C7—C8	114.08 (19)	H14B—C14—H14C	109.5
C6—C7—H7A	108.7	C8—C15—H15A	109.5
C8—C7—H7A	108.7	C8—C15—H15B	109.5
C6—C7—H7B	108.7	H15A—C15—H15B	109.5
C8—C7—H7B	108.7	C8—C15—H15C	109.5
H7A—C7—H7B	107.6	H15A—C15—H15C	109.5
C15—C8—C7	109.6 (2)	H15B—C15—H15C	109.5
C15—C8—C16	107.7 (2)	C8—C16—H16A	109.5
C7—C8—C16	107.9 (2)	C8—C16—H16B	109.5
C15—C8—C8A	114.3 (2)	H16A—C16—H16B	109.5
C7—C8—C8A	109.00 (17)	C8—C16—H16C	109.5
C16—C8—C8A	108.25 (19)	H16A—C16—H16C	109.5
C9—C8A—C4B	109.05 (18)	H16B—C16—H16C	109.5
C9—C8A—C8	113.59 (17)	O2—C17—O1	123.7 (2)
C4B—C8A—C8	117.57 (17)	O2—C17—C18	126.0 (2)
C9—C8A—H8A	105.2	O1—C17—C18	110.3 (2)
C4B—C8A—H8A	105.2	C17—C18—H18A	109.5
C8—C8A—H8A	105.2	C17—C18—H18B	109.5
C10—C9—C8A	111.51 (18)	H18A—C18—H18B	109.5
C10—C9—H9A	109.3	C17—C18—H18C	109.5
C8A—C9—H9A	109.3	H18A—C18—H18C	109.5
C10—C9—H9B	109.3	H18B—C18—H18C	109.5
C8A—C9—H9B	109.3	C17—O1—C2	117.79 (16)

Experimental details

Crystal data
Chemical formula	C₂₂H₃₂O₂
M_r	328.47
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	180
a, b, c (Å)	7.4250 (2), 10.5716 (3), 12.0747 (3)
β (°)	90.124 (2)
V (Å³)	947.79 (4)
Z	2
Radiation type	Cu Kα
µ (mm⁻¹)	0.55
Crystal size (mm)	0.38 × 0.38 × 0.14

Data collection
Diffractometer	Agilent Xcalibur (Eos, Gemini ultra) diffractometer
Absorption correction	Multi-scan Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm (CrysAlis PRO, Agilent, 2012)
T_min, T_max	0.860, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	4370, 2511, 2490
R_int	0.012
θ_max (°)	60.7
(sin θ/λ)_max (Å⁻¹)	0.566

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.075, 1.04
No. of reflections	2511
No. of parameters	225
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.13, −0.14
Absolute structure	Refined as an inversion twin.
Absolute structure parameter	0.0 (3)

Computer programs: CrysAlis PRO (Agilent, 2012), SIR97 (Altomare et al., 1999), SHELXL2013 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996) ORTEP-3 for Windows (Farrugia, 2012).

References

Agilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Abingdon, England. Google Scholar
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Barrero, A. F., Quílez del Moral, J. F., Lucas, R., Payá, M., Akssira, M., Akaad, S. & Mellouki, F. (2003). J. Nat. Prod. 66, 844–50. Web of Science CrossRef PubMed CAS Google Scholar
Bernabeu, A., Shapiro, S. & Villalain, J. (2002). Chem. Phys. Lipids, 119, 33–39. Web of Science CrossRef PubMed CAS Google Scholar
Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA. Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Flack, H. D. & Bernardinelli, G. (2000). J. Appl. Cryst. 33, 1143–1148. Web of Science CrossRef CAS IUCr Journals Google Scholar
Haraguchi, H., Oike, S., Muroi, H. & Kubo, I. (1996). Planta Med. 62, 122–125. CrossRef CAS PubMed Web of Science Google Scholar
Marcos, I. S., Cubillo, M. A. & Moro, R. F. (2003). Tetrahedron Lett. 44, 8831–8835. Web of Science CSD CrossRef CAS Google Scholar
Pettit, G. R., Tan, R., Northen, J. S., Herald, D. L., Chapuis, J.-C. & Pettit, R. K. (2004). J. Nat. Prod. 67, 1476–1482. Web of Science CSD CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Short, W. F. & Stromberg, H. (1937). J. Chem. Soc. pp. 516–520. CrossRef Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tacon, C., Drguantaieric, M., Smith, P. J. & Chibale, K. (2012). Bioorg. Med. Chem. 20, 893–902. Web of Science CrossRef CAS PubMed Google Scholar
Zeroual, A., Mazoir, N., Daran, J.-C., Akssira, M. & Benharref, A. (2008). Acta Cryst. E64, o604–o605. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.