(4aS,6cS)-8-Hydr­oxy-9-isopropyl-4,4,6c-trimethyl-1,2,3,4,4a,5,6,6c-octa­hydro­phenanthren-3-one

The title compound, C₂₀H₂₈O₂, is a diterpenoid isolated from the wood of the Tetraclinis articulata plant. The mol­ecule contains three fused rings which exhibit different conformations. The non-aromatic oxo-substituted ring has a chair conformation, while the central ring has an envelope conformation. The crystal structure is stabilized by O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.038
• wR factor = 0.105
• Data-to-parameter ratio = 15.5

checkCIF/PLATON results

No syntax errors found



Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           30.54
           From the CIF: _reflns_number_total               2891
           Count of symmetry unique reflns         2948
           Completeness (_total/calc)             98.07%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C4A    = .          S
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C6C    = .          R

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   0 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
              Please specify the role of each of the co-authors
              for your paper.

Author Response: The authors Zeroual and Mazoir performed isolation of the substance and analyse by NMR. Maya , data collection. I resolved the structure using Wingx. Benharref and Auhmani are director and co-director of thesis.

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

---

S1. Comment

Diterpenoids producing by plants exhibit well known pharmacological activities (Atta-ur-Rahman & Choudary, 1999; Panter et al., 2002; Azucena & Mobashery, 2001; He et al., 1999; Ulusu et al., 2002). In order to isolate similar compounds, we have undertaken this work. Thus, hexane extraction of wood from the Tetraclinis articulata plant (Abbas et al., 2006), followed by chromatography on a silica gel column, gave the diterpene compound (I) as the sole product in good yield.

The molecule (I) is composed of three fused six-membered rings. The non aromatic six membered ring C4a/C6C/C1/C2/C3/C4 has a chair conformation, as indicated by the total puckering amplitude QT = 0.48 (2)Å and spherical polar angle θ =167.65 (1)° with φ = 163.52 (2)°. The six membered ring C5/C6/C6a/C6b/C6c/C4a displays an envelope conformation with QT = 0.54 (1) Å, θ =52.01 (1)° (Cremer & Pople, 1975). Molecules are linked by intermolecular O—H···O hydrogen bonds (Table 1, Figure 2) involving the carbonyl and the hydroxyl groups. The hydrogen bonds system results in the formation of chains parallel to the b axis.

Related literature

For related literature, see: Abbas et al. (2006); Atta-ur-Rahman & Choudary (1999); Azucena & Mobashery (2001); Cremer & Pople (1975); He et al. (1999); Panter et al. (2002); Ulusu et al. (2002).

S2. Experimental

The first study was undertaken on a hexane extract. Subsequent studies were carried out by continuous hexane extraction of thuya wood with a soxhlet apparatus, over a 48 h period. The residue obtained, after evaporation of hexane, was chromatographed on a silica gel column with hexane–ethyl acetate (96:4 v/v) as the eluant. This allowed the isolation of compound (I) in 85% yield, as the sole product. Suitable crystals of compound (I) were obtained by evaporation of a dichloromethane solution; m.p. 464–465 K. Spectroscopic analysis: ¹H NMR (300 MHz, CDCl₃, δ, p.p.m.): 6.55 (H-7,s), 6.80 (H-10, s), 5.20 (OH, s), 1.28 (H-12, d, J = 10 Hz), 1.29 (H-13, d, J = 10 Hz), 1.15 (H-14, s), 1.12 (H-15, s), 1.13 (H-16, s); ¹³ C NMR (75 MHz, CDCl₃, δ, p.p.m.): 34.6 (C1), 37.6 (C2), 218.2 (C3), 47.6 (C4), 50.8 (C4a), 20.4 (C5), 29.3 (C6), 128.4 (C6a), 145.5 (C6b), 34.8 (C6c), 111.9 (C7), 151.7 (C8), 132.9 (C9), 126.8 (C10), 22.5 (C11), 24.6 (C12), 24.7 (C13), 26.7 (C14), 21.0 (C15), 21.3 (C16).

S3. Refinement

All H atoms were fixed geometrically and treated as riding with C—H = 0.93 Å (aromatic), 0.96Å (methyl), 0.97 Å (methylene), 0.98Å (methine) and O—H= 0.82 Å with U_iso(H) = 1.2U_eq(aromatic, methylene, methine and OH) or U_iso(H) = 1.5U_eq(methyl). In the absence of significant anomalous scattering, the absolute configuration could not be reliably determined. The Friedel pairs were merged and any references to the Flack parameter was removed.

Computing details

Data collection: APEX-W2K-NT (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia,1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. Molecular structure of compound I, showing the atomic labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as spheres of arbitrary radii.
	Fig. 2. Partial packing diagram, showing the O—H···O interactions (dashed lines) and the formation of a chain parallel to the b axis. H atoms not involved in hydrogen bonding have been omitted for clarity. [Symmetry code: (i) -x, y - 1/2, 1/2 - z.]

(4aS,6cS)-8-Hydroxy-9-isopropyl-4,4,6c-trimethyl-1,2,3,4,4a,5,6,6c- octahydrophenanthren-3-one

Crystal data

C20H28O2	F(000) = 656
Mr = 300.42	Dx = 1.175 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 7546 reflections
a = 7.5554 (3) Å	θ = 2.9–30.5°
b = 13.3987 (6) Å	µ = 0.07 mm^−1
c = 16.7825 (6) Å	T = 298 K
V = 1698.94 (12) Å^3	Prism, colourless
Z = 4	0.5 × 0.4 × 0.3 mm

Data collection

Bruker X8 APEX CCD area-detector diffractometer	2669 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.029
Graphite monochromator	θmax = 30.5°, θmin = 3.0°
φ and ω scans	h = −10→10
26366 measured reflections	k = −18→19
2891 independent reflections	l = −21→23

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0575P)^2 + 0.4523P] where P = (Fo^2 + 2Fc^2)/3
2891 reflections	(Δ/σ)max < 0.001
187 parameters	Δρmax = 0.51 e Å^−3
0 restraints	Δρmin = −0.39 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.0911 (2)	0.63566 (12)	0.27798 (10)	0.023
H13A	0.0367	0.6657	0.2315	0.028*
H13B	0.0788	0.5639	0.2731	0.028*
C2	−0.0064 (2)	0.66929 (13)	0.35037 (12)	0.030
H18A	0.0365	0.6321	0.3961	0.037*
H18B	−0.1310	0.6539	0.3439	0.037*
C3	0.0129 (2)	0.77835 (11)	0.36676 (9)	0.0193 (3)
C4	0.1986 (2)	0.82219 (11)	0.36287 (9)	0.0176 (3)
C4A	0.3067 (2)	0.77609 (10)	0.29306 (8)	0.0145 (2)
H2	0.2598	0.8076	0.2448	0.017*
C5	0.5023 (2)	0.80471 (11)	0.29528 (9)	0.0202 (3)
H12A	0.5135	0.8749	0.3084	0.024*
H12B	0.5619	0.7665	0.3364	0.024*
C6	0.5902 (2)	0.78463 (11)	0.21496 (9)	0.0201 (3)
H9A	0.5797	0.8441	0.1824	0.024*
H9B	0.7153	0.7727	0.2238	0.024*
C6A	0.5147 (2)	0.69726 (10)	0.16901 (8)	0.0154 (3)
C6B	0.37190 (19)	0.64076 (10)	0.19642 (8)	0.0146 (2)
C6C	0.28920 (19)	0.66197 (10)	0.27846 (9)	0.0153 (3)
C7	0.3095 (2)	0.56252 (10)	0.14895 (8)	0.0160 (3)
H5	0.2158	0.5236	0.1671	0.019*
C8	0.3845 (2)	0.54175 (10)	0.07531 (8)	0.0168 (3)
C9	0.5259 (2)	0.59822 (10)	0.04603 (8)	0.0168 (3)
C10	0.5878 (2)	0.67493 (11)	0.09440 (8)	0.0173 (3)
H7	0.6823	0.7132	0.0764	0.021*
C11	0.6034 (2)	0.57533 (11)	−0.03525 (9)	0.0221 (3)
H17	0.6046	0.5026	−0.0413	0.026*
C12	0.4833 (3)	0.61746 (14)	−0.10046 (9)	0.0291 (4)
H15A	0.5331	0.6027	−0.1518	0.044*
H15B	0.4733	0.6884	−0.0942	0.044*
H15C	0.3681	0.5876	−0.0964	0.044*
C13	0.7933 (3)	0.61207 (15)	−0.04667 (11)	0.0322 (4)
H20A	0.8333	0.5949	−0.0992	0.048*
H20B	0.8687	0.5812	−0.0078	0.048*
H20C	0.7970	0.6832	−0.0402	0.048*
C14	0.3857 (3)	0.59435 (12)	0.33870 (9)	0.0249 (3)
H16A	0.3380	0.6052	0.3910	0.037*
H16B	0.5097	0.6100	0.3387	0.037*
H16C	0.3694	0.5257	0.3239	0.037*
C15	0.2800 (2)	0.80433 (13)	0.44633 (9)	0.0261 (3)
H19A	0.3979	0.8309	0.4477	0.039*
H19B	0.2835	0.7340	0.4571	0.039*
H19C	0.2089	0.8370	0.4859	0.039*
C16	0.1831 (2)	0.93550 (12)	0.34921 (10)	0.0246 (3)
H14A	0.2993	0.9643	0.3465	0.037*
H14B	0.1186	0.9651	0.3925	0.037*
H14C	0.1217	0.9478	0.3001	0.037*
O1	0.32359 (17)	0.46427 (8)	0.02913 (7)	0.0228 (2)
H1	0.2418	0.4362	0.0521	0.034*
O2	−0.11497 (17)	0.82758 (9)	0.38691 (7)	0.0265 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.022	0.021	0.028	−0.006	0.008	−0.009
C2	0.021	0.023	0.047	−0.003	0.011	−0.009
C3	0.0204 (7)	0.0205 (6)	0.0170 (6)	0.0031 (6)	0.0006 (5)	−0.0014 (5)
C4	0.0194 (7)	0.0163 (6)	0.0170 (6)	0.0027 (5)	−0.0025 (5)	−0.0032 (5)
C4A	0.0157 (6)	0.0122 (5)	0.0155 (6)	0.0006 (5)	−0.0019 (5)	−0.0009 (4)
C5	0.0179 (7)	0.0196 (6)	0.0232 (7)	−0.0041 (5)	−0.0015 (6)	−0.0038 (5)
C6	0.0193 (7)	0.0180 (6)	0.0229 (6)	−0.0058 (5)	0.0011 (6)	−0.0005 (5)
C6A	0.0149 (6)	0.0126 (5)	0.0188 (6)	−0.0012 (5)	0.0002 (5)	0.0010 (4)
C6B	0.0146 (6)	0.0122 (5)	0.0170 (6)	0.0001 (5)	0.0009 (5)	0.0009 (4)
C6C	0.0159 (7)	0.0119 (5)	0.0180 (6)	0.0000 (5)	0.0022 (5)	0.0000 (5)
C7	0.0173 (6)	0.0129 (5)	0.0178 (6)	−0.0024 (5)	0.0024 (5)	0.0003 (5)
C8	0.0199 (7)	0.0127 (6)	0.0179 (6)	0.0004 (5)	0.0013 (5)	−0.0004 (5)
C9	0.0191 (7)	0.0140 (6)	0.0174 (6)	0.0011 (5)	0.0032 (5)	0.0019 (5)
C10	0.0170 (7)	0.0144 (6)	0.0207 (6)	−0.0016 (5)	0.0027 (5)	0.0033 (5)
C11	0.0278 (8)	0.0174 (6)	0.0210 (6)	0.0004 (6)	0.0088 (6)	0.0011 (5)
C12	0.0381 (10)	0.0311 (8)	0.0180 (6)	−0.0031 (8)	0.0024 (7)	0.0009 (6)
C13	0.0291 (9)	0.0392 (9)	0.0283 (8)	−0.0005 (8)	0.0124 (7)	0.0037 (7)
C14	0.0356 (9)	0.0185 (7)	0.0206 (6)	0.0084 (7)	0.0030 (7)	0.0043 (5)
C15	0.0298 (9)	0.0322 (8)	0.0162 (6)	0.0053 (7)	−0.0048 (6)	−0.0047 (6)
C16	0.0261 (8)	0.0167 (6)	0.0309 (8)	0.0028 (6)	−0.0039 (7)	−0.0066 (6)
O1	0.0295 (6)	0.0186 (5)	0.0202 (5)	−0.0076 (5)	0.0060 (5)	−0.0047 (4)
O2	0.0216 (6)	0.0288 (6)	0.0291 (6)	0.0078 (5)	0.0021 (5)	−0.0042 (5)

Geometric parameters (Å, º)

C1—C2	1.490 (2)	C7—C8	1.3877 (19)
C1—C6C	1.538 (2)	C7—H5	0.9300
C1—H13A	0.9700	C8—O1	1.3748 (17)
C1—H13B	0.9700	C8—C9	1.398 (2)
C2—C3	1.494 (2)	C9—C10	1.391 (2)
C2—H18A	0.9700	C9—C11	1.516 (2)
C2—H18B	0.9700	C10—H7	0.9300
C3—O2	1.2177 (19)	C11—C13	1.529 (2)
C3—C4	1.522 (2)	C11—C12	1.530 (2)
C4—C16	1.540 (2)	C11—H17	0.9800
C4—C15	1.548 (2)	C12—H15A	0.9600
C4—C4A	1.556 (2)	C12—H15B	0.9600
C4A—C5	1.527 (2)	C12—H15C	0.9600
C4A—C6C	1.5541 (19)	C13—H20A	0.9600
C4A—H2	0.9800	C13—H20B	0.9600
C5—C6	1.526 (2)	C13—H20C	0.9600
C5—H12A	0.9700	C14—H16A	0.9600
C5—H12B	0.9700	C14—H16B	0.9600
C6—C6A	1.513 (2)	C14—H16C	0.9600
C6—H9A	0.9700	C15—H19A	0.9600
C6—H9B	0.9700	C15—H19B	0.9600
C6A—C6B	1.396 (2)	C15—H19C	0.9600
C6A—C10	1.401 (2)	C16—H14A	0.9600
C6B—C7	1.3986 (19)	C16—H14B	0.9600
C6B—C6C	1.5384 (19)	C16—H14C	0.9600
C6C—C14	1.541 (2)	O1—H1	0.8200
C2—C1—C6C	114.05 (14)	C14—C6C—C4A	115.77 (12)
C2—C1—H13A	108.7	C8—C7—C6B	121.33 (13)
C6C—C1—H13A	108.7	C8—C7—H5	119.3
C2—C1—H13B	108.7	C6B—C7—H5	119.3
C6C—C1—H13B	108.7	O1—C8—C7	121.11 (13)
H13A—C1—H13B	107.6	O1—C8—C9	117.79 (13)
C1—C2—C3	113.42 (15)	C7—C8—C9	121.10 (13)
C1—C2—H18A	108.9	C10—C9—C8	116.86 (13)
C3—C2—H18A	108.9	C10—C9—C11	123.02 (13)
C1—C2—H18B	108.9	C8—C9—C11	120.12 (13)
C3—C2—H18B	108.9	C9—C10—C6A	123.15 (13)
H18A—C2—H18B	107.7	C9—C10—H7	118.4
O2—C3—C2	120.23 (16)	C6A—C10—H7	118.4
O2—C3—C4	122.28 (13)	C9—C11—C13	114.20 (14)
C2—C3—C4	117.35 (14)	C9—C11—C12	109.89 (13)
C3—C4—C16	108.46 (13)	C13—C11—C12	110.37 (13)
C3—C4—C15	105.51 (13)	C9—C11—H17	107.4
C16—C4—C15	108.51 (13)	C13—C11—H17	107.4
C3—C4—C4A	111.28 (11)	C12—C11—H17	107.4
C16—C4—C4A	108.62 (13)	C11—C12—H15A	109.5
C15—C4—C4A	114.28 (12)	C11—C12—H15B	109.5
C5—C4A—C6C	109.47 (12)	H15A—C12—H15B	109.5
C5—C4A—C4	112.95 (12)	C11—C12—H15C	109.5
C6C—C4A—C4	117.68 (12)	H15A—C12—H15C	109.5
C5—C4A—H2	105.2	H15B—C12—H15C	109.5
C6C—C4A—H2	105.2	C11—C13—H20A	109.5
C4—C4A—H2	105.2	C11—C13—H20B	109.5
C6—C5—C4A	110.79 (12)	H20A—C13—H20B	109.5
C6—C5—H12A	109.5	C11—C13—H20C	109.5
C4A—C5—H12A	109.5	H20A—C13—H20C	109.5
C6—C5—H12B	109.5	H20B—C13—H20C	109.5
C4A—C5—H12B	109.5	C6C—C14—H16A	109.5
H12A—C5—H12B	108.1	C6C—C14—H16B	109.5
C6A—C6—C5	115.00 (12)	H16A—C14—H16B	109.5
C6A—C6—H9A	108.5	C6C—C14—H16C	109.5
C5—C6—H9A	108.5	H16A—C14—H16C	109.5
C6A—C6—H9B	108.5	H16B—C14—H16C	109.5
C5—C6—H9B	108.5	C4—C15—H19A	109.5
H9A—C6—H9B	107.5	C4—C15—H19B	109.5
C6B—C6A—C10	118.92 (13)	H19A—C15—H19B	109.5
C6B—C6A—C6	122.87 (13)	C4—C15—H19C	109.5
C10—C6A—C6	118.17 (13)	H19A—C15—H19C	109.5
C6A—C6B—C7	118.64 (13)	H19B—C15—H19C	109.5
C6A—C6B—C6C	120.57 (12)	C4—C16—H14A	109.5
C7—C6B—C6C	120.76 (12)	C4—C16—H14B	109.5
C1—C6C—C6B	110.39 (12)	H14A—C16—H14B	109.5
C1—C6C—C14	109.21 (13)	C4—C16—H14C	109.5
C6B—C6C—C14	106.64 (12)	H14A—C16—H14C	109.5
C1—C6C—C4A	108.02 (12)	H14B—C16—H14C	109.5
C6B—C6C—C4A	106.76 (11)	C8—O1—H1	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^i	0.82	2.02	2.7969 (13)	158

Symmetry code: (i) −x, y−1/2, −z+1/2.