(4aS,4bR,7R,10aS)-3,7-Dimethyl-10a-(propan-2-yl)-1,4,4a,4b,5,6,7,8,10,10a-deca-hydro-phenanthrene-1,4-dione.

In the title compound, C(19)H(26)O(2), the A ring adopts a chair conformation, whereas the B and C rings both adopt distorted half-chair conformations with the quaternary C atom common to both rings lying 0.577 (3) and 0.648 (3) Å out of the approximate plane defined by the remaining five C atoms (r.m.s. deviations = 0.1386 and 0.1156 Å) for the B and C rings, respectively. Mol-ecules are assembled in the crystal through C-H⋯O inter-actions involving both carbonyl O atoms, which lead to supra-molecular chains aligned along the b axis.

Related literature

For background to the biological activity of some diterpene compounds, see: Guo et al. (2011 ▶); Slusarczyk et al. (2011 ▶). For the synthesis, see: Ferreira (2002 ▶). For conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C19H26O2

M = 286.40

Monoclinic,

a = 10.882 (1) Å

b = 6.6015 (9) Å

c = 11.656 (1) Å

β = 102.53 (2)°

V = 817.40 (16) Å3

Z = 2

Mo Kα radiation

μ = 0.07 mm−1

T = 290 K

0.15 × 0.10 × 0.08 mm

Data collection

Enraf–Nonius CAD-4 Mach 3 diffractometer

2470 measured reflections

2334 independent reflections

1100 reflections with I > 2σ(I)

R int = 0.045

3 standard reflections every 30 min intensity decay: 1.4%

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.122

S = 0.98

2334 reflections

191 parameters

1 restraint

H-atom parameters constrained

Δρmax = 0.18 e Å−3

Δρmin = −0.18 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶), DIAMOND (Brandenburg, 2006 ▶) and MarvinSketch (Chemaxon, 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681104517X/hg5119sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681104517X/hg5119Isup2.hkl

Supplementary material file. DOI: 10.1107/S160053681104517X/hg5119Isup3.cml

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

C19H26O2	F(000) = 312
Mr = 286.40	Dx = 1.164 Mg m−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 10.882 (1) Å	θ = 10.3–18.3°
b = 6.6015 (9) Å	µ = 0.07 mm−1
c = 11.656 (1) Å	T = 290 K
β = 102.53 (2)°	Irregular, colourless
V = 817.40 (16) Å3	0.15 × 0.10 × 0.08 mm
Z = 2

Enraf–Nonius CAD-4 Mach 3 diffractometer	Rint = 0.045
Radiation source: fine-focus sealed tube	θmax = 29.0°, θmin = 1.8°
graphite	h = −14→14
ω/–2θ scans	k = 0→8
2470 measured reflections	l = 0→15
2334 independent reflections	3 standard reflections every 30 min
1100 reflections with I > 2σ(I)	intensity decay: 1.4%

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122	H-atom parameters constrained
S = 0.98	w = 1/[σ2(Fo2) + (0.058P)2] where P = (Fo2 + 2Fc2)/3
2334 reflections	(Δ/σ)max < 0.001
191 parameters	Δρmax = 0.18 e Å−3
1 restraint	Δρmin = −0.18 e Å−3

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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.

	x	y	z	Uiso*/Ueq
C1	0.0639 (2)	0.5986 (4)	0.7953 (2)	0.0384 (6)
H1	0.0437	0.4610	0.8167	0.046*
C2	0.2045 (2)	0.5917 (4)	0.7858 (2)	0.0343 (6)
H2	0.2203	0.4553	0.7591	0.041*
C3	0.2885 (2)	0.6188 (4)	0.9059 (2)	0.0370 (6)
C4	0.3242 (2)	0.8281 (5)	0.9474 (3)	0.0410 (7)
C5	0.2941 (3)	0.9818 (5)	0.8724 (2)	0.0432 (7)
H5	0.3120	1.1128	0.9005	0.052*
C6	0.2337 (3)	0.9551 (4)	0.7467 (2)	0.0415 (7)
C7	0.2397 (3)	0.7433 (4)	0.6959 (2)	0.0372 (7)
C8	0.1491 (3)	0.7223 (5)	0.5767 (2)	0.0471 (7)
H8A	0.1565	0.8416	0.5300	0.057*
H8B	0.1741	0.6062	0.5361	0.057*
C9	0.0148 (3)	0.6975 (5)	0.5837 (2)	0.0467 (7)
H9	−0.0461	0.7233	0.5159	0.056*
C10	−0.0248 (2)	0.6416 (4)	0.6784 (2)	0.0422 (7)
C11	−0.1614 (3)	0.6269 (6)	0.6815 (3)	0.0566 (8)
H11A	−0.1813	0.4878	0.6972	0.068*
H11B	−0.2119	0.6641	0.6052	0.068*
C12	−0.1952 (3)	0.7642 (6)	0.7752 (3)	0.0559 (9)
H12	−0.2815	0.7323	0.7813	0.067*
C13	−0.1084 (3)	0.7170 (6)	0.8930 (3)	0.0537 (8)
H13A	−0.1243	0.5799	0.9159	0.064*
H13B	−0.1274	0.8083	0.9520	0.064*
C14	0.0305 (2)	0.7376 (5)	0.8899 (2)	0.0437 (7)
H14A	0.0819	0.7022	0.9661	0.052*
H14B	0.0485	0.8771	0.8733	0.052*
C15	0.3875 (3)	0.8537 (6)	1.0739 (2)	0.0571 (9)
H15A	0.4098	0.9934	1.0890	0.086*
H15B	0.4621	0.7718	1.0914	0.086*
H15C	0.3311	0.8124	1.1225	0.086*
C16	0.3807 (3)	0.7097 (5)	0.6859 (2)	0.0479 (7)
H16	0.4338	0.7277	0.7647	0.057*
C17	0.4060 (3)	0.4981 (6)	0.6445 (3)	0.0711 (11)
H17A	0.3798	0.3992	0.6947	0.107*
H17B	0.4943	0.4827	0.6475	0.107*
H17C	0.3597	0.4788	0.5653	0.107*
C18	0.4232 (4)	0.8654 (8)	0.6055 (4)	0.0969 (16)
H18A	0.4079	0.9995	0.6311	0.145*
H18B	0.3769	0.8457	0.5263	0.145*
H18C	0.5115	0.8488	0.6086	0.145*
C19	−0.1910 (4)	0.9882 (7)	0.7419 (3)	0.0748 (11)
H19A	−0.2468	1.0110	0.6671	0.112*
H19B	−0.1068	1.0240	0.7372	0.112*
H19C	−0.2169	1.0700	0.8005	0.112*
O1	0.32371 (19)	0.4746 (3)	0.96994 (17)	0.0523 (6)
O2	0.1854 (2)	1.0979 (3)	0.6885 (2)	0.0685 (7)

	U11	U22	U33	U12	U13	U23
C1	0.0447 (15)	0.0296 (14)	0.0405 (14)	−0.0061 (13)	0.0087 (11)	0.0004 (13)
C2	0.0455 (15)	0.0231 (14)	0.0352 (13)	0.0008 (13)	0.0106 (12)	−0.0005 (12)
C3	0.0402 (15)	0.0341 (16)	0.0387 (14)	0.0034 (13)	0.0130 (12)	0.0045 (14)
C4	0.0362 (13)	0.0428 (18)	0.0443 (16)	−0.0067 (13)	0.0093 (12)	−0.0088 (15)
C5	0.0481 (16)	0.0291 (15)	0.0515 (16)	−0.0075 (15)	0.0089 (13)	−0.0057 (16)
C6	0.0456 (15)	0.0309 (16)	0.0481 (17)	−0.0071 (14)	0.0100 (13)	0.0028 (15)
C7	0.0477 (15)	0.0298 (16)	0.0355 (14)	−0.0007 (13)	0.0121 (12)	0.0008 (12)
C8	0.0636 (19)	0.0435 (18)	0.0357 (14)	0.0031 (16)	0.0135 (13)	0.0008 (14)
C9	0.0567 (18)	0.0395 (17)	0.0395 (15)	−0.0014 (14)	0.0005 (14)	−0.0069 (14)
C10	0.0456 (16)	0.0366 (17)	0.0421 (15)	−0.0070 (13)	0.0041 (12)	−0.0100 (13)
C11	0.0468 (17)	0.061 (2)	0.0570 (18)	−0.0093 (17)	0.0007 (14)	0.0006 (18)
C12	0.0418 (15)	0.069 (2)	0.0583 (19)	−0.0028 (16)	0.0130 (14)	0.0004 (18)
C13	0.0484 (17)	0.064 (2)	0.0515 (17)	0.0008 (17)	0.0178 (13)	0.0047 (17)
C14	0.0427 (15)	0.0497 (19)	0.0393 (15)	−0.0011 (14)	0.0103 (12)	−0.0004 (14)
C15	0.0494 (17)	0.070 (2)	0.0501 (18)	−0.0090 (18)	0.0060 (14)	−0.0125 (18)
C16	0.0486 (17)	0.0531 (19)	0.0451 (15)	0.0001 (16)	0.0170 (13)	0.0074 (16)
C17	0.076 (2)	0.073 (3)	0.070 (2)	0.021 (2)	0.0293 (18)	−0.007 (2)
C18	0.081 (3)	0.098 (4)	0.127 (4)	0.004 (3)	0.058 (3)	0.046 (3)
C19	0.079 (2)	0.073 (3)	0.075 (2)	0.020 (2)	0.0200 (19)	0.003 (2)
O1	0.0620 (13)	0.0425 (13)	0.0506 (12)	0.0052 (11)	0.0081 (10)	0.0102 (11)
O2	0.0952 (18)	0.0276 (12)	0.0723 (15)	0.0052 (13)	−0.0047 (13)	0.0091 (12)

C1—C10	1.515 (4)	C11—H11B	0.9700
C1—C14	1.538 (4)	C12—C13	1.521 (4)
C1—C2	1.559 (3)	C12—C19	1.532 (6)
C1—H1	0.9800	C12—H12	0.9800
C2—C3	1.507 (4)	C13—C14	1.526 (4)
C2—C7	1.556 (3)	C13—H13A	0.9700
C2—H2	0.9800	C13—H13B	0.9700
C3—O1	1.219 (3)	C14—H14A	0.9700
C3—C4	1.488 (4)	C14—H14B	0.9700
C4—C5	1.333 (4)	C15—H15A	0.9600
C4—C15	1.495 (4)	C15—H15B	0.9600
C5—C6	1.480 (4)	C15—H15C	0.9600
C5—H5	0.9300	C16—C17	1.522 (5)
C6—O2	1.213 (4)	C16—C18	1.528 (5)
C6—C7	1.526 (4)	C16—H16	0.9800
C7—C8	1.525 (4)	C17—H17A	0.9600
C7—C16	1.580 (4)	C17—H17B	0.9600
C8—C9	1.491 (4)	C17—H17C	0.9600
C8—H8A	0.9700	C18—H18A	0.9600
C8—H8B	0.9700	C18—H18B	0.9600
C9—C10	1.322 (4)	C18—H18C	0.9600
C9—H9	0.9300	C19—H19A	0.9600
C10—C11	1.498 (4)	C19—H19B	0.9600
C11—C12	1.524 (5)	C19—H19C	0.9600
C11—H11A	0.9700
C10—C1—C14	109.2 (2)	C13—C12—C11	109.0 (3)
C10—C1—C2	112.7 (2)	C13—C12—C19	112.3 (3)
C14—C1—C2	117.2 (2)	C11—C12—C19	111.6 (3)
C10—C1—H1	105.6	C13—C12—H12	107.9
C14—C1—H1	105.6	C11—C12—H12	107.9
C2—C1—H1	105.6	C19—C12—H12	107.9
C3—C2—C7	111.2 (2)	C12—C13—C14	112.6 (2)
C3—C2—C1	109.7 (2)	C12—C13—H13A	109.1
C7—C2—C1	114.7 (2)	C14—C13—H13A	109.1
C3—C2—H2	106.9	C12—C13—H13B	109.1
C7—C2—H2	106.9	C14—C13—H13B	109.1
C1—C2—H2	106.9	H13A—C13—H13B	107.8
O1—C3—C4	120.0 (2)	C13—C14—C1	110.7 (2)
O1—C3—C2	121.5 (3)	C13—C14—H14A	109.5
C4—C3—C2	118.4 (2)	C1—C14—H14A	109.5
C5—C4—C3	118.9 (2)	C13—C14—H14B	109.5
C5—C4—C15	123.8 (3)	C1—C14—H14B	109.5
C3—C4—C15	117.2 (3)	H14A—C14—H14B	108.1
C4—C5—C6	123.5 (3)	C4—C15—H15A	109.5
C4—C5—H5	118.3	C4—C15—H15B	109.5
C6—C5—H5	118.3	H15A—C15—H15B	109.5
O2—C6—C5	120.4 (3)	C4—C15—H15C	109.5
O2—C6—C7	123.0 (2)	H15A—C15—H15C	109.5
C5—C6—C7	116.5 (2)	H15B—C15—H15C	109.5
C8—C7—C6	111.3 (2)	C17—C16—C18	108.9 (3)
C8—C7—C2	110.5 (2)	C17—C16—C7	113.4 (3)
C6—C7—C2	106.9 (2)	C18—C16—C7	112.3 (3)
C8—C7—C16	111.5 (2)	C17—C16—H16	107.3
C6—C7—C16	106.3 (2)	C18—C16—H16	107.3
C2—C7—C16	110.1 (2)	C7—C16—H16	107.3
C9—C8—C7	114.1 (2)	C16—C17—H17A	109.5
C9—C8—H8A	108.7	C16—C17—H17B	109.5
C7—C8—H8A	108.7	H17A—C17—H17B	109.5
C9—C8—H8B	108.7	C16—C17—H17C	109.5
C7—C8—H8B	108.7	H17A—C17—H17C	109.5
H8A—C8—H8B	107.6	H17B—C17—H17C	109.5
C10—C9—C8	125.3 (3)	C16—C18—H18A	109.5
C10—C9—H9	117.4	C16—C18—H18B	109.5
C8—C9—H9	117.4	H18A—C18—H18B	109.5
C9—C10—C11	122.9 (3)	C16—C18—H18C	109.5
C9—C10—C1	122.9 (2)	H18A—C18—H18C	109.5
C11—C10—C1	114.1 (2)	H18B—C18—H18C	109.5
C10—C11—C12	111.9 (3)	C12—C19—H19A	109.5
C10—C11—H11A	109.2	C12—C19—H19B	109.5
C12—C11—H11A	109.2	H19A—C19—H19B	109.5
C10—C11—H11B	109.2	C12—C19—H19C	109.5
C12—C11—H11B	109.2	H19A—C19—H19C	109.5
H11A—C11—H11B	107.9	H19B—C19—H19C	109.5
C10—C1—C2—C3	161.1 (2)	C1—C2—C7—C16	−175.1 (2)
C14—C1—C2—C3	33.1 (3)	C6—C7—C8—C9	−76.9 (3)
C10—C1—C2—C7	35.2 (3)	C2—C7—C8—C9	41.7 (3)
C14—C1—C2—C7	−92.8 (3)	C16—C7—C8—C9	164.6 (2)
C7—C2—C3—O1	−143.0 (3)	C7—C8—C9—C10	−18.3 (4)
C1—C2—C3—O1	89.0 (3)	C8—C9—C10—C11	177.6 (3)
C7—C2—C3—C4	39.3 (3)	C8—C9—C10—C1	1.2 (5)
C1—C2—C3—C4	−88.6 (3)	C14—C1—C10—C9	122.4 (3)
O1—C3—C4—C5	174.1 (3)	C2—C1—C10—C9	−9.7 (4)
C2—C3—C4—C5	−8.2 (4)	C14—C1—C10—C11	−54.3 (3)
O1—C3—C4—C15	−8.5 (4)	C2—C1—C10—C11	173.6 (2)
C2—C3—C4—C15	169.2 (2)	C9—C10—C11—C12	−121.1 (3)
C3—C4—C5—C6	−4.0 (4)	C1—C10—C11—C12	55.6 (4)
C15—C4—C5—C6	178.8 (3)	C10—C11—C12—C13	−54.3 (4)
C4—C5—C6—O2	164.9 (3)	C10—C11—C12—C19	70.3 (4)
C4—C5—C6—C7	−16.9 (4)	C11—C12—C13—C14	56.3 (4)
O2—C6—C7—C8	−15.4 (4)	C19—C12—C13—C14	−67.8 (4)
C5—C6—C7—C8	166.5 (2)	C12—C13—C14—C1	−57.5 (4)
O2—C6—C7—C2	−136.2 (3)	C10—C1—C14—C13	54.0 (3)
C5—C6—C7—C2	45.7 (3)	C2—C1—C14—C13	−176.3 (2)
O2—C6—C7—C16	106.2 (3)	C8—C7—C16—C17	−62.7 (3)
C5—C6—C7—C16	−72.0 (3)	C6—C7—C16—C17	175.8 (2)
C3—C2—C7—C8	−176.7 (2)	C2—C7—C16—C17	60.4 (3)
C1—C2—C7—C8	−51.5 (3)	C8—C7—C16—C18	61.2 (4)
C3—C2—C7—C6	−55.4 (3)	C6—C7—C16—C18	−60.3 (3)
C1—C2—C7—C6	69.8 (3)	C2—C7—C16—C18	−175.7 (3)
C3—C2—C7—C16	59.6 (3)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O2i	0.98	2.50	3.443 (3)	161
C5—H5···O1ii	0.93	2.52	3.438 (4)	171

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯O2i	0.98	2.50	3.443 (3)	161
C5—H5⋯O1ii	0.93	2.52	3.438 (4)	171

Symmetry codes: (i) ; (ii) .