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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 4| April 2012| Page o1263
doi:10.1107/S1600536812013207

6-Methyl­ideneandrost-4-ene-3,17-dione

L. C. R. Andrade,a M. J. M. de Almeida,a* F. M. Fernandes Roleira,b C. L. Varelab and E. J. Tavares da Silvab

aCEMDRX, Department of Physics, Faculty of Sciences and Technology, University of Coimbra, P-3004-516 Coimbra, Portugal, and bCenter for Pharmaceutical Studies, Pharmaceutical Chemistry Group, Faculty of Pharmacy, University of Coimbra, P-3000-548 Coimbra, Portugal
*Correspondence e-mail: ze@pollux.fis.uc.pt

(Received 13 March 2012; accepted 26 March 2012; online 31 March 2012)

In the title compound, C20H26O2, which is the 6-methyl­ene derivative of androstenedione and a synthetic percursor of exemestane, the steroid A ring approximates to a sofa (or envelope) conformation, with the methyl­ene group adjacent to the link to the B ring lying out of the plane of the other atoms. The B and C rings have slightly flattened chair conformations and the D ring is an envelope, with the CH group forming the flap. In the crystal, mol­ecules are linked by two distinct C—H⋯O hydrogen bonds, involving acidic H atoms close to C=C and C=O double bonds.

Related literature

For the synthesis of the title compound, see: Annen et al. (1982[Annen, K., Hofmeister, H., Laurent, H. & Wiechert, R. (1982). Synthesis, 2, 34-40.]). For exemestane aromatase inhibitor potency, see: Furr (2006[Furr, B. J. A. (2006). In Aromatase Inhibitors (Milestones in Drug Therapy).Basel: Birkhäuser Verlag.]). For elucidation of structural requirements needed to achieve anti­tumor activity, see: Cepa et al. (2005[Cepa, M., Tavares da Silva, E. J., Correia-da-Silva, G., Roleira, F. M. & Teixeira, N. A. (2005). J. Med. Chem. 48, 6379-6385.]). For puckering parameters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]) and for asymmetry parameters, see: Duax & Norton (1975[Duax, W. L. & Norton, D. A. (1975). In Atlas of Steroid Structure. New York: Plenum Press.]); Altona et al. (1968[Altona, C., Geise, H. J. & Romers, C. (1968). Tetrahedron, 24, 13-32.]). For reference bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data

  • C20H26O2

  • Mr = 298.41

  • Monoclinic, P 21

  • a = 9.2343 (4) Å

  • b = 8.7162 (4) Å

  • c = 11.0798 (5) Å

  • β = 108.197 (2)°

  • V = 847.19 (7) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 293 K

  • 0.24 × 0.17 × 0.05 mm
Data collection

  • Bruker APEX CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2000[Sheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.]) Tmin = 0.835, Tmax = 0.996

  • 18560 measured reflections

  • 1979 independent reflections

  • 1433 reflections with I > 2σ(I)

  • Rint = 0.036
Refinement

  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.100

  • S = 1.02

  • 1979 reflections

  • 201 parameters

  • 1 restraint

  • H-atom parameters constrained

  • Δρmax = 0.14 e Å−3

  • Δρmin = −0.13 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C2—H2A⋯O17i 0.97 2.43 3.345 (3) 158
C66—H66A⋯O3ii 0.93 2.47 3.365 (3) 163
Symmetry codes: (i) x, y, z-1; (ii) [-x+1, y+{\script{1\over 2}}, -z-1].

Data collection: SMART (Bruker, 2003)[Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]; cell refinement: SAINT (Bruker, 2003)[Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]; data reduction: SAINT[Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812013207/hb6686sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812013207/hb6686Isup2.hkl

checkCIF report


Comment top

The title compound is the 6-methylene derivative of androstenedione, the natural substrate of aromatase, and is a key synthetic precursor of exemestane, the most potent steroid aromatase inhibitor clinically used in the breast cancer treatment (Furr, 2006). Following our work on the determination of several androstane structures of potential aromatase inhibitors and intermediates of their syntheses, the X-ray analysis of compound (I) aims to contribute to the elucidation of structural requirements needed to achieve antitumor activity (Cepa et al., 2005). From the single-crystal diffraction measurements one can conclude that bond lengths are within normal values (Allen et al., 1987) with an average Csp3–Csp3 bond length of 1.534 (13) Å. Due to the C4═C5 double bond ring A addopts a 1α–sofa conformation, slightly distorted towards a 1α,2β–halfchair one [asymmetry parameters (Duax and Norton, 1975): ΔCs(1)=7.8 (3), ΔC2(1,2)=17.5 (3) and ΔC2(2,3)=51.4 (4)°]. Rings B and C have slightly flattened chair conformations evidenced by average torsion angle values of 50 (3) and 55 (3)°, respectively. The five member D ring assumes a 14α–envelope conformation [puckering parameters (Cremer and Pople, 1975): q2=0.414 (3) Å and φ2=211.3 (4)°; pseudo-rotation (Altona et al., 1968) and asymmetry parameters: Δ=25.4 (4), φm=42.7 (2)°, ΔCs(14)=4.8 (3) and ΔC2(13,14)=14.9 (3)°]. The pseudo-torsion angle C19–C10···C13–C18 of 2.2 (2)° indicates that the molecule is only slightly twisted. The 6-methylene group is in a beta equatorial position with an angle of 63.8 (2)°. Due to the acidic character of hydrogen atoms close to C═C or C═O double bonds, cohesion of the crystal can be attributed to a net of two C–H···O pseudohydrogen bonds, namely C2–H2A···O17 and C66–H66A···O3, connecting molecules aligned almost along [101], respectively head to tail and head to head.

Related literature top

For the synthesis of the title compound, see: Annen et al. (1982). For exemestane aromatase inhibitor potency, see: Furr (2006). For elucidation of structural requirements needed to achieve antitumor activity, see: Cepa et al. (2005). For puckering parameters, see: Cremer & Pople (1975) and for asymmetry parameters, see: Duax & Norton (1975); Altona et al. (1968). For reference bond-length data, see: Allen et al. (1987).

Experimental top

6-Methylenandrost-4-ene-3,17-dione was prepared according to a described procedure (Annen et al., 1982) as follows. A suspension of anhydrous sodium acetate (1.0 g, 12.19 mmol) in dry chloroform (30.0 cm3) containing formaldehyde dimethyl acetal (30.0 cm3, 340.0 mmol) and phosphoryl choride (1.9 cm3, 20.0 mmol) was heated at reflux for 1 h. Androstenedione (773.5 mg, 2.70 mmol) was then added and the mixture was supplemented dropwise with phosphoryl choride (1.9 cm3, 20.0 mmol) over a period of 3 h 30 min. The reaction mixture was subsequently refluxed under nitrogen for 10 h, after which was allowed to cool to room temperature. A saturated aqueous solution of sodium carbonate was then added under vigorous stirring until the aqueous layer became alkaline. This mixture was extracted with chloroform (200 cm3) and then the organic phase was washed with water (4x100 cm3), dried over anhydrous MgSO4, filtered and concentrated to dryness. The resulting residue was purified by a silica gel 60 column chromatography (hexane/diethyl ether) affording the pure 6-methylenandrost-4-ene-3,17-dione (134.8 mg, 17%). Suitable crystals for X-ray studies were grown from slow evaporation from acetone/n-hexane: Mp. 435–437 K [lit 440 K (Annen et al., 1982)]; IR νmax (NaCl plates, CHCl3) cm-1: 3084 (=C–H), 1738 (C17=O), 1671 (C3=O), 1599 (C═C); 1H NMR (600 MHz, CDCl3): δ 0.78 (3H, s, 18–H3), 1.00 (3H, s, 19–H3), 4.87 (1H, t, ═CH2), 4.97 (1H, t, ═CH2), 5.79 (1H, s, 4–H); 13C NMR (150 MHz, CDCl3): δ 11.5 (C18), 14.9 (C19), 18.2, 19.5, 29.0, 31.6, 32.9, 33.0, 33.6, 36.6, 36.9, 45.3, 48.9, 50.3, 112.4 (═CH2), 119.6 (C4), 143.2 (C6), 166.3 (C5), 197.4 (C3), 217.8 (C17).

Refinement top

All hydrogen atoms were refined as riding on their parent atoms. Number of Friedel pairs measured: 1606 (45%). Due to the lack of any strong anomalous scatterer atom at the Mo Kα wavelength, refinement of Flack parameter was inconclusive. However the absolute configuration of the molecule is known from the synthetic route.

Structure description top

The title compound is the 6-methylene derivative of androstenedione, the natural substrate of aromatase, and is a key synthetic precursor of exemestane, the most potent steroid aromatase inhibitor clinically used in the breast cancer treatment (Furr, 2006). Following our work on the determination of several androstane structures of potential aromatase inhibitors and intermediates of their syntheses, the X-ray analysis of compound (I) aims to contribute to the elucidation of structural requirements needed to achieve antitumor activity (Cepa et al., 2005). From the single-crystal diffraction measurements one can conclude that bond lengths are within normal values (Allen et al., 1987) with an average Csp3–Csp3 bond length of 1.534 (13) Å. Due to the C4═C5 double bond ring A addopts a 1α–sofa conformation, slightly distorted towards a 1α,2β–halfchair one [asymmetry parameters (Duax and Norton, 1975): ΔCs(1)=7.8 (3), ΔC2(1,2)=17.5 (3) and ΔC2(2,3)=51.4 (4)°]. Rings B and C have slightly flattened chair conformations evidenced by average torsion angle values of 50 (3) and 55 (3)°, respectively. The five member D ring assumes a 14α–envelope conformation [puckering parameters (Cremer and Pople, 1975): q2=0.414 (3) Å and φ2=211.3 (4)°; pseudo-rotation (Altona et al., 1968) and asymmetry parameters: Δ=25.4 (4), φm=42.7 (2)°, ΔCs(14)=4.8 (3) and ΔC2(13,14)=14.9 (3)°]. The pseudo-torsion angle C19–C10···C13–C18 of 2.2 (2)° indicates that the molecule is only slightly twisted. The 6-methylene group is in a beta equatorial position with an angle of 63.8 (2)°. Due to the acidic character of hydrogen atoms close to C═C or C═O double bonds, cohesion of the crystal can be attributed to a net of two C–H···O pseudohydrogen bonds, namely C2–H2A···O17 and C66–H66A···O3, connecting molecules aligned almost along [101], respectively head to tail and head to head.

For the synthesis of the title compound, see: Annen et al. (1982). For exemestane aromatase inhibitor potency, see: Furr (2006). For elucidation of structural requirements needed to achieve antitumor activity, see: Cepa et al. (2005). For puckering parameters, see: Cremer & Pople (1975) and for asymmetry parameters, see: Duax & Norton (1975); Altona et al. (1968). For reference bond-length data, see: Allen et al. (1987).

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of the title compound. Displacement ellipsoids are drawn at the 50% level.
6-Methylideneandrost-4-ene-3,17-dione top
Crystal data top
C20H26O2F(000) = 324
Mr = 298.41Dx = 1.170 Mg m−3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
a = 9.2343 (4) ÅCell parameters from 4974 reflections
b = 8.7162 (4) Åθ = 3.0–22.5°
c = 11.0798 (5) ŵ = 0.07 mm−1
β = 108.197 (2)°T = 293 K
V = 847.19 (7) Å3Prism, colourless
Z = 20.24 × 0.17 × 0.05 mm
Data collection top
Bruker APEX CCD
diffractometer		1979 independent reflections
Radiation source: fine-focus sealed tube1433 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
φ and ω scansθmax = 28.2°, θmin = 3.4°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)		h = −11→11
Tmin = 0.835, Tmax = 0.996k = −11→11
18560 measured reflectionsl = −14→14
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.100H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0554P)2 + 0.0289P]
where P = (Fo2 + 2Fc2)/3
1979 reflections(Δ/σ)max < 0.001
201 parametersΔρmax = 0.14 e Å−3
1 restraintΔρmin = −0.13 e Å−3
Crystal data top
C20H26O2V = 847.19 (7) Å3
Mr = 298.41Z = 2
Monoclinic, P21Mo Kα radiation
a = 9.2343 (4) ŵ = 0.07 mm−1
b = 8.7162 (4) ÅT = 293 K
c = 11.0798 (5) Å0.24 × 0.17 × 0.05 mm
β = 108.197 (2)°
Data collection top
Bruker APEX CCD
diffractometer		1979 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)		1433 reflections with I > 2σ(I)
Tmin = 0.835, Tmax = 0.996Rint = 0.036
18560 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0401 restraint
wR(F2) = 0.100H-atom parameters constrained
S = 1.02Δρmax = 0.14 e Å−3
1979 reflectionsΔρmin = −0.13 e Å−3
201 parameters
Special details top

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. 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 > σ(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
xyzUiso*/Ueq
O30.4355 (3)0.2091 (3)−0.50154 (16)0.0901 (7)
O170.8776 (2)0.1624 (3)0.50156 (17)0.0859 (7)
C10.6765 (3)0.0835 (3)−0.1938 (2)0.0482 (6)
H1A0.75570.0070−0.16270.058*
H1B0.58870.0510−0.17000.058*
C20.6322 (3)0.0896 (3)−0.3384 (2)0.0587 (7)
H2A0.72340.1037−0.36280.070*
H2B0.5867−0.0076−0.37300.070*
C30.5234 (3)0.2148 (3)−0.3938 (2)0.0579 (7)
C40.5301 (3)0.3509 (3)−0.31480 (19)0.0519 (6)
H40.46320.4312−0.34810.062*
C50.6281 (3)0.3660 (3)−0.19633 (19)0.0406 (5)
C60.6402 (3)0.5144 (3)−0.12840 (19)0.0429 (5)
C70.6506 (3)0.5032 (3)0.00948 (19)0.0466 (6)
H7A0.55140.47570.01580.056*
H7B0.67790.60280.04910.056*
C80.7671 (3)0.3855 (3)0.08090 (18)0.0393 (5)
H80.86900.41980.08320.047*
C90.7337 (3)0.2294 (3)0.01266 (18)0.0366 (5)
H90.62930.20270.00870.044*
C100.7340 (2)0.2374 (2)−0.12870 (18)0.0393 (5)
C110.8350 (3)0.1008 (3)0.0884 (2)0.0539 (6)
H11A0.93840.11680.08710.065*
H11B0.79990.00360.04680.065*
C120.8365 (3)0.0905 (3)0.2274 (2)0.0568 (7)
H12A0.73700.05840.23020.068*
H12B0.91070.01460.27220.068*
C130.8765 (3)0.2447 (3)0.29190 (19)0.0473 (6)
C140.7637 (3)0.3646 (3)0.21692 (19)0.0423 (5)
H140.66230.32400.20930.051*
C150.7863 (3)0.5024 (4)0.3071 (2)0.0586 (7)
H15A0.69770.56900.28400.070*
H15B0.87560.56160.30790.070*
C160.8078 (4)0.4237 (4)0.4357 (2)0.0741 (9)
H16A0.88490.47650.50280.089*
H16B0.71300.42400.45610.089*
C170.8573 (3)0.2610 (4)0.4218 (2)0.0597 (7)
C181.0444 (3)0.2877 (4)0.3115 (2)0.0665 (8)
H18A1.10980.21000.36150.100*
H18B1.06670.38450.35460.100*
H18C1.06110.29530.23040.100*
C190.8931 (3)0.2731 (3)−0.1379 (2)0.0536 (6)
H19A0.88790.2794−0.22570.080*
H19B0.96250.1930−0.09710.080*
H19C0.92820.3691−0.09680.080*
C660.6447 (3)0.6472 (3)−0.1846 (2)0.0609 (7)
H66A0.64030.6498−0.26960.073*
H66B0.65230.7382−0.13910.073*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O30.1235 (18)0.0890 (16)0.0410 (9)−0.0040 (15)0.0016 (11)−0.0116 (10)
O170.0974 (16)0.1097 (18)0.0578 (10)0.0235 (14)0.0349 (10)0.0346 (12)
C10.0620 (15)0.0377 (14)0.0482 (12)−0.0032 (12)0.0218 (11)−0.0054 (11)
C20.0806 (18)0.0504 (16)0.0498 (13)−0.0085 (15)0.0272 (12)−0.0157 (12)
C30.0765 (18)0.0587 (17)0.0386 (11)−0.0084 (15)0.0182 (12)−0.0052 (12)
C40.0636 (15)0.0513 (15)0.0383 (11)0.0048 (14)0.0121 (10)0.0033 (12)
C50.0513 (14)0.0367 (13)0.0371 (10)−0.0006 (11)0.0188 (10)0.0038 (10)
C60.0525 (14)0.0361 (13)0.0389 (11)0.0049 (12)0.0125 (10)0.0032 (10)
C70.0623 (15)0.0358 (13)0.0402 (11)0.0095 (13)0.0138 (10)−0.0020 (10)
C80.0412 (12)0.0393 (14)0.0362 (9)0.0002 (10)0.0103 (9)0.0002 (9)
C90.0408 (12)0.0322 (13)0.0376 (10)0.0003 (10)0.0133 (9)0.0017 (9)
C100.0488 (14)0.0333 (13)0.0385 (10)−0.0033 (11)0.0174 (9)−0.0018 (9)
C110.0662 (16)0.0441 (16)0.0491 (12)0.0100 (13)0.0146 (11)0.0050 (11)
C120.0657 (17)0.0513 (17)0.0520 (13)0.0094 (14)0.0161 (11)0.0140 (12)
C130.0435 (13)0.0575 (17)0.0395 (11)0.0015 (12)0.0111 (10)0.0080 (11)
C140.0407 (12)0.0480 (14)0.0367 (10)0.0015 (12)0.0098 (9)−0.0005 (11)
C150.0689 (17)0.0625 (17)0.0412 (12)0.0014 (15)0.0124 (11)−0.0081 (12)
C160.085 (2)0.095 (2)0.0402 (13)0.0036 (19)0.0172 (13)−0.0058 (15)
C170.0503 (15)0.086 (2)0.0418 (12)0.0018 (15)0.0129 (10)0.0095 (14)
C180.0447 (15)0.093 (2)0.0583 (15)0.0041 (15)0.0103 (11)0.0095 (15)
C190.0528 (14)0.0550 (16)0.0605 (14)−0.0022 (13)0.0284 (11)−0.0029 (12)
C660.086 (2)0.0426 (15)0.0537 (14)0.0026 (15)0.0218 (13)0.0052 (12)
Geometric parameters (Å, º) top
O3—C31.217 (3)C11—C121.539 (3)
O17—C171.205 (3)C11—H11A0.9700
C1—C21.526 (3)C11—H11B0.9700
C1—C101.537 (3)C12—C131.512 (4)
C1—H1A0.9700C12—H12A0.9700
C1—H1B0.9700C12—H12B0.9700
C2—C31.481 (4)C13—C171.511 (3)
C2—H2A0.9700C13—C141.525 (3)
C2—H2B0.9700C13—C181.543 (4)
C3—C41.464 (4)C14—C151.534 (4)
C4—C51.348 (3)C14—H140.9800
C4—H40.9300C15—C161.538 (4)
C5—C61.483 (3)C15—H15A0.9700
C5—C101.521 (3)C15—H15B0.9700
C6—C661.322 (4)C16—C171.512 (5)
C6—C71.504 (3)C16—H16A0.9700
C7—C81.518 (3)C16—H16B0.9700
C7—H7A0.9700C18—H18A0.9600
C7—H7B0.9700C18—H18B0.9600
C8—C141.528 (3)C18—H18C0.9600
C8—C91.540 (3)C19—H19A0.9600
C8—H80.9800C19—H19B0.9600
C9—C111.531 (3)C19—H19C0.9600
C9—C101.568 (3)C66—H66A0.9300
C9—H90.9800C66—H66B0.9300
C10—C191.536 (3)
C2—C1—C10113.72 (19)C9—C11—H11B108.8
C2—C1—H1A108.8C12—C11—H11B108.8
C10—C1—H1A108.8H11A—C11—H11B107.7
C2—C1—H1B108.8C13—C12—C11110.2 (2)
C10—C1—H1B108.8C13—C12—H12A109.6
H1A—C1—H1B107.7C11—C12—H12A109.6
C3—C2—C1112.7 (2)C13—C12—H12B109.6
C3—C2—H2A109.0C11—C12—H12B109.6
C1—C2—H2A109.0H12A—C12—H12B108.1
C3—C2—H2B109.0C17—C13—C12116.7 (2)
C1—C2—H2B109.0C17—C13—C14101.05 (19)
H2A—C2—H2B107.8C12—C13—C14109.11 (18)
O3—C3—C4120.7 (3)C17—C13—C18104.76 (19)
O3—C3—C2122.3 (2)C12—C13—C18111.6 (2)
C4—C3—C2116.9 (2)C14—C13—C18113.3 (2)
C5—C4—C3123.5 (2)C13—C14—C8113.47 (18)
C5—C4—H4118.3C13—C14—C15104.54 (17)
C3—C4—H4118.3C8—C14—C15120.6 (2)
C4—C5—C6120.0 (2)C13—C14—H14105.7
C4—C5—C10122.7 (2)C8—C14—H14105.7
C6—C5—C10117.22 (17)C15—C14—H14105.7
C66—C6—C5122.25 (18)C14—C15—C16101.9 (2)
C66—C6—C7122.3 (2)C14—C15—H15A111.4
C5—C6—C7115.46 (19)C16—C15—H15A111.4
C6—C7—C8112.53 (18)C14—C15—H15B111.4
C6—C7—H7A109.1C16—C15—H15B111.4
C8—C7—H7A109.1H15A—C15—H15B109.3
C6—C7—H7B109.1C17—C16—C15106.3 (2)
C8—C7—H7B109.1C17—C16—H16A110.5
H7A—C7—H7B107.8C15—C16—H16A110.5
C7—C8—C14111.40 (17)C17—C16—H16B110.5
C7—C8—C9109.92 (16)C15—C16—H16B110.5
C14—C8—C9108.45 (18)H16A—C16—H16B108.7
C7—C8—H8109.0O17—C17—C13126.4 (3)
C14—C8—H8109.0O17—C17—C16125.3 (2)
C9—C8—H8109.0C13—C17—C16108.3 (2)
C11—C9—C8112.54 (16)C13—C18—H18A109.5
C11—C9—C10112.90 (17)C13—C18—H18B109.5
C8—C9—C10112.83 (16)H18A—C18—H18B109.5
C11—C9—H9105.9C13—C18—H18C109.5
C8—C9—H9105.9H18A—C18—H18C109.5
C10—C9—H9105.9H18B—C18—H18C109.5
C5—C10—C19107.41 (18)C10—C19—H19A109.5
C5—C10—C1109.70 (17)C10—C19—H19B109.5
C19—C10—C1110.02 (19)H19A—C19—H19B109.5
C5—C10—C9108.90 (16)C10—C19—H19C109.5
C19—C10—C9112.03 (17)H19A—C19—H19C109.5
C1—C10—C9108.75 (16)H19B—C19—H19C109.5
C9—C11—C12113.8 (2)C6—C66—H66A120.0
C9—C11—H11A108.8C6—C66—H66B120.0
C12—C11—H11A108.8H66A—C66—H66B120.0
C10—C1—C2—C3−52.5 (3)C8—C9—C10—C1966.5 (2)
C1—C2—C3—O3−153.9 (3)C11—C9—C10—C159.3 (2)
C1—C2—C3—C428.6 (3)C8—C9—C10—C1−171.65 (17)
O3—C3—C4—C5−177.9 (3)C8—C9—C11—C1250.9 (3)
C2—C3—C4—C5−0.4 (4)C10—C9—C11—C12−180.0 (2)
C3—C4—C5—C6172.8 (2)C9—C11—C12—C13−53.2 (3)
C3—C4—C5—C10−4.8 (4)C11—C12—C13—C17170.15 (19)
C4—C5—C6—C66−43.6 (3)C11—C12—C13—C1456.5 (3)
C10—C5—C6—C66134.1 (2)C11—C12—C13—C18−69.4 (2)
C4—C5—C6—C7137.7 (2)C17—C13—C14—C8174.9 (2)
C10—C5—C6—C7−44.6 (3)C12—C13—C14—C8−61.5 (2)
C66—C6—C7—C8−130.9 (3)C18—C13—C14—C863.4 (3)
C5—C6—C7—C847.7 (3)C17—C13—C14—C1541.7 (2)
C6—C7—C8—C14−174.15 (19)C12—C13—C14—C15165.22 (19)
C6—C7—C8—C9−53.9 (3)C18—C13—C14—C15−69.8 (2)
C7—C8—C9—C11−172.96 (18)C7—C8—C14—C13178.7 (2)
C14—C8—C9—C11−51.0 (2)C9—C8—C14—C1357.6 (2)
C7—C8—C9—C1057.8 (2)C7—C8—C14—C15−56.3 (3)
C14—C8—C9—C10179.86 (17)C9—C8—C14—C15−177.35 (19)
C4—C5—C10—C19101.4 (2)C13—C14—C15—C16−39.5 (2)
C6—C5—C10—C19−76.3 (2)C8—C14—C15—C16−168.6 (2)
C4—C5—C10—C1−18.2 (3)C14—C15—C16—C1721.5 (3)
C6—C5—C10—C1164.16 (18)C12—C13—C17—O1734.0 (4)
C4—C5—C10—C9−137.1 (2)C14—C13—C17—O17152.1 (3)
C6—C5—C10—C945.3 (2)C18—C13—C17—O17−90.0 (3)
C2—C1—C10—C546.0 (3)C12—C13—C17—C16−146.0 (2)
C2—C1—C10—C19−72.0 (2)C14—C13—C17—C16−27.8 (3)
C2—C1—C10—C9164.96 (19)C18—C13—C17—C1690.0 (3)
C11—C9—C10—C5178.85 (19)C15—C16—C17—O17−176.0 (3)
C8—C9—C10—C5−52.1 (2)C15—C16—C17—C133.9 (3)
C11—C9—C10—C19−62.5 (2)C19—C10—C13—C182.2 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2A···O17i0.972.433.345 (3)158
C66—H66A···O3ii0.932.473.365 (3)163
Symmetry codes: (i) x, y, z−1; (ii) −x+1, y+1/2, −z−1.

Experimental details

Crystal data
Chemical formulaC20H26O2
Mr298.41
Crystal system, space groupMonoclinic, P21
Temperature (K)293
a, b, c (Å)9.2343 (4), 8.7162 (4), 11.0798 (5)
β (°) 108.197 (2)
V (Å3)847.19 (7)
Z2
Radiation typeMo Kα
µ (mm−1)0.07
Crystal size (mm)0.24 × 0.17 × 0.05
Data collection
DiffractometerBruker APEX CCD
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2000)
Tmin, Tmax0.835, 0.996
No. of measured, independent and
observed [I > 2σ(I)] reflections		18560, 1979, 1433
Rint0.036
(sin θ/λ)max (Å−1)0.666
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.100, 1.02
No. of reflections1979
No. of parameters201
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.14, −0.13

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2A···O17i0.972.433.345 (3)158
C66—H66A···O3ii0.932.473.365 (3)163
Symmetry codes: (i) x, y, z−1; (ii) −x+1, y+1/2, −z−1.
 

Acknowledgements

This work was supported by funds from FEDER via the COMPETE (Programa Operacional Factores de Competitividade) programme and by the FCT (Fundação para a Ciência e a Tecnologia, project PEst-C/FIS/UI0036/2011).

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CSD CrossRef Web of Science Google Scholar
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 First citationCepa, M., Tavares da Silva, E. J., Correia-da-Silva, G., Roleira, F. M. & Teixeira, N. A. (2005). J. Med. Chem. 48, 6379–6385.  Web of Science CrossRef PubMed CAS Google Scholar
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 First citationDuax, W. L. & Norton, D. A. (1975). In Atlas of Steroid Structure. New York: Plenum Press.  Google Scholar
 First citationFurr, B. J. A. (2006). In Aromatase Inhibitors (Milestones in Drug Therapy).Basel: Birkhäuser Verlag.  Google Scholar
 First citationSheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
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ISSN: 2056-9890
Volume 68| Part 4| April 2012| Page o1263
doi:10.1107/S1600536812013207
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