6-Methyl-ideneandrost-4-ene-3,17-dione.

In the title compound, C(20)H(26)O(2), which is the 6-methyl-ene derivative of androstenedione and a synthetic percursor of exemestane, the steroid A ring approximates to a sofa (or envelope) conformation, with the methyl-ene 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, mol-ecules 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 ▶). 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

Crystal data

C20H26O2

M = 298.41

Monoclinic,

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 ▶) T min = 0.835, T max = 0.996

18560 measured reflections

1979 independent reflections

1433 reflections with I > 2σ(I)

R int = 0.036

Refinement

R[F 2 > 2σ(F 2)] = 0.040

wR(F 2) = 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

Data collection: SMART (Bruker, 2003) ▶; cell refinement: SAINT (Bruker, 2003) ▶; data reduction: SAINT ▶; 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.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812013207/hb6686sup1.cif

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

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

C20H26O2	F(000) = 324
Mr = 298.41	Dx = 1.170 Mg m−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 9.2343 (4) Å	Cell parameters from 4974 reflections
b = 8.7162 (4) Å	θ = 3.0–22.5°
c = 11.0798 (5) Å	µ = 0.07 mm−1
β = 108.197 (2)°	T = 293 K
V = 847.19 (7) Å3	Prism, colourless
Z = 2	0.24 × 0.17 × 0.05 mm

Bruker APEX CCD diffractometer	1979 independent reflections
Radiation source: fine-focus sealed tube	1433 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
φ and ω scans	θmax = 28.2°, θmin = 3.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −11→11
Tmin = 0.835, Tmax = 0.996	k = −11→11
18560 measured reflections	l = −14→14

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)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.100	H-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 parameters	Δρmax = 0.14 e Å−3
1 restraint	Δρmin = −0.13 e Å−3

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.

	x	y	z	Uiso*/Ueq
O3	0.4355 (3)	0.2091 (3)	−0.50154 (16)	0.0901 (7)
O17	0.8776 (2)	0.1624 (3)	0.50156 (17)	0.0859 (7)
C1	0.6765 (3)	0.0835 (3)	−0.1938 (2)	0.0482 (6)
H1A	0.7557	0.0070	−0.1627	0.058*
H1B	0.5887	0.0510	−0.1700	0.058*
C2	0.6322 (3)	0.0896 (3)	−0.3384 (2)	0.0587 (7)
H2A	0.7234	0.1037	−0.3628	0.070*
H2B	0.5867	−0.0076	−0.3730	0.070*
C3	0.5234 (3)	0.2148 (3)	−0.3938 (2)	0.0579 (7)
C4	0.5301 (3)	0.3509 (3)	−0.31480 (19)	0.0519 (6)
H4	0.4632	0.4312	−0.3481	0.062*
C5	0.6281 (3)	0.3660 (3)	−0.19633 (19)	0.0406 (5)
C6	0.6402 (3)	0.5144 (3)	−0.12840 (19)	0.0429 (5)
C7	0.6506 (3)	0.5032 (3)	0.00948 (19)	0.0466 (6)
H7A	0.5514	0.4757	0.0158	0.056*
H7B	0.6779	0.6028	0.0491	0.056*
C8	0.7671 (3)	0.3855 (3)	0.08090 (18)	0.0393 (5)
H8	0.8690	0.4198	0.0832	0.047*
C9	0.7337 (3)	0.2294 (3)	0.01266 (18)	0.0366 (5)
H9	0.6293	0.2027	0.0087	0.044*
C10	0.7340 (2)	0.2374 (2)	−0.12870 (18)	0.0393 (5)
C11	0.8350 (3)	0.1008 (3)	0.0884 (2)	0.0539 (6)
H11A	0.9384	0.1168	0.0871	0.065*
H11B	0.7999	0.0036	0.0468	0.065*
C12	0.8365 (3)	0.0905 (3)	0.2274 (2)	0.0568 (7)
H12A	0.7370	0.0584	0.2302	0.068*
H12B	0.9107	0.0146	0.2722	0.068*
C13	0.8765 (3)	0.2447 (3)	0.29190 (19)	0.0473 (6)
C14	0.7637 (3)	0.3646 (3)	0.21692 (19)	0.0423 (5)
H14	0.6623	0.3240	0.2093	0.051*
C15	0.7863 (3)	0.5024 (4)	0.3071 (2)	0.0586 (7)
H15A	0.6977	0.5690	0.2840	0.070*
H15B	0.8756	0.5616	0.3079	0.070*
C16	0.8078 (4)	0.4237 (4)	0.4357 (2)	0.0741 (9)
H16A	0.8849	0.4765	0.5028	0.089*
H16B	0.7130	0.4240	0.4561	0.089*
C17	0.8573 (3)	0.2610 (4)	0.4218 (2)	0.0597 (7)
C18	1.0444 (3)	0.2877 (4)	0.3115 (2)	0.0665 (8)
H18A	1.1098	0.2100	0.3615	0.100*
H18B	1.0667	0.3845	0.3546	0.100*
H18C	1.0611	0.2953	0.2304	0.100*
C19	0.8931 (3)	0.2731 (3)	−0.1379 (2)	0.0536 (6)
H19A	0.8879	0.2794	−0.2257	0.080*
H19B	0.9625	0.1930	−0.0971	0.080*
H19C	0.9282	0.3691	−0.0968	0.080*
C66	0.6447 (3)	0.6472 (3)	−0.1846 (2)	0.0609 (7)
H66A	0.6403	0.6498	−0.2696	0.073*
H66B	0.6523	0.7382	−0.1391	0.073*

	U11	U22	U33	U12	U13	U23
O3	0.1235 (18)	0.0890 (16)	0.0410 (9)	−0.0040 (15)	0.0016 (11)	−0.0116 (10)
O17	0.0974 (16)	0.1097 (18)	0.0578 (10)	0.0235 (14)	0.0349 (10)	0.0346 (12)
C1	0.0620 (15)	0.0377 (14)	0.0482 (12)	−0.0032 (12)	0.0218 (11)	−0.0054 (11)
C2	0.0806 (18)	0.0504 (16)	0.0498 (13)	−0.0085 (15)	0.0272 (12)	−0.0157 (12)
C3	0.0765 (18)	0.0587 (17)	0.0386 (11)	−0.0084 (15)	0.0182 (12)	−0.0052 (12)
C4	0.0636 (15)	0.0513 (15)	0.0383 (11)	0.0048 (14)	0.0121 (10)	0.0033 (12)
C5	0.0513 (14)	0.0367 (13)	0.0371 (10)	−0.0006 (11)	0.0188 (10)	0.0038 (10)
C6	0.0525 (14)	0.0361 (13)	0.0389 (11)	0.0049 (12)	0.0125 (10)	0.0032 (10)
C7	0.0623 (15)	0.0358 (13)	0.0402 (11)	0.0095 (13)	0.0138 (10)	−0.0020 (10)
C8	0.0412 (12)	0.0393 (14)	0.0362 (9)	0.0002 (10)	0.0103 (9)	0.0002 (9)
C9	0.0408 (12)	0.0322 (13)	0.0376 (10)	0.0003 (10)	0.0133 (9)	0.0017 (9)
C10	0.0488 (14)	0.0333 (13)	0.0385 (10)	−0.0033 (11)	0.0174 (9)	−0.0018 (9)
C11	0.0662 (16)	0.0441 (16)	0.0491 (12)	0.0100 (13)	0.0146 (11)	0.0050 (11)
C12	0.0657 (17)	0.0513 (17)	0.0520 (13)	0.0094 (14)	0.0161 (11)	0.0140 (12)
C13	0.0435 (13)	0.0575 (17)	0.0395 (11)	0.0015 (12)	0.0111 (10)	0.0080 (11)
C14	0.0407 (12)	0.0480 (14)	0.0367 (10)	0.0015 (12)	0.0098 (9)	−0.0005 (11)
C15	0.0689 (17)	0.0625 (17)	0.0412 (12)	0.0014 (15)	0.0124 (11)	−0.0081 (12)
C16	0.085 (2)	0.095 (2)	0.0402 (13)	0.0036 (19)	0.0172 (13)	−0.0058 (15)
C17	0.0503 (15)	0.086 (2)	0.0418 (12)	0.0018 (15)	0.0129 (10)	0.0095 (14)
C18	0.0447 (15)	0.093 (2)	0.0583 (15)	0.0041 (15)	0.0103 (11)	0.0095 (15)
C19	0.0528 (14)	0.0550 (16)	0.0605 (14)	−0.0022 (13)	0.0284 (11)	−0.0029 (12)
C66	0.086 (2)	0.0426 (15)	0.0537 (14)	0.0026 (15)	0.0218 (13)	0.0052 (12)

O3—C3	1.217 (3)	C11—C12	1.539 (3)
O17—C17	1.205 (3)	C11—H11A	0.9700
C1—C2	1.526 (3)	C11—H11B	0.9700
C1—C10	1.537 (3)	C12—C13	1.512 (4)
C1—H1A	0.9700	C12—H12A	0.9700
C1—H1B	0.9700	C12—H12B	0.9700
C2—C3	1.481 (4)	C13—C17	1.511 (3)
C2—H2A	0.9700	C13—C14	1.525 (3)
C2—H2B	0.9700	C13—C18	1.543 (4)
C3—C4	1.464 (4)	C14—C15	1.534 (4)
C4—C5	1.348 (3)	C14—H14	0.9800
C4—H4	0.9300	C15—C16	1.538 (4)
C5—C6	1.483 (3)	C15—H15A	0.9700
C5—C10	1.521 (3)	C15—H15B	0.9700
C6—C66	1.322 (4)	C16—C17	1.512 (5)
C6—C7	1.504 (3)	C16—H16A	0.9700
C7—C8	1.518 (3)	C16—H16B	0.9700
C7—H7A	0.9700	C18—H18A	0.9600
C7—H7B	0.9700	C18—H18B	0.9600
C8—C14	1.528 (3)	C18—H18C	0.9600
C8—C9	1.540 (3)	C19—H19A	0.9600
C8—H8	0.9800	C19—H19B	0.9600
C9—C11	1.531 (3)	C19—H19C	0.9600
C9—C10	1.568 (3)	C66—H66A	0.9300
C9—H9	0.9800	C66—H66B	0.9300
C10—C19	1.536 (3)
C2—C1—C10	113.72 (19)	C9—C11—H11B	108.8
C2—C1—H1A	108.8	C12—C11—H11B	108.8
C10—C1—H1A	108.8	H11A—C11—H11B	107.7
C2—C1—H1B	108.8	C13—C12—C11	110.2 (2)
C10—C1—H1B	108.8	C13—C12—H12A	109.6
H1A—C1—H1B	107.7	C11—C12—H12A	109.6
C3—C2—C1	112.7 (2)	C13—C12—H12B	109.6
C3—C2—H2A	109.0	C11—C12—H12B	109.6
C1—C2—H2A	109.0	H12A—C12—H12B	108.1
C3—C2—H2B	109.0	C17—C13—C12	116.7 (2)
C1—C2—H2B	109.0	C17—C13—C14	101.05 (19)
H2A—C2—H2B	107.8	C12—C13—C14	109.11 (18)
O3—C3—C4	120.7 (3)	C17—C13—C18	104.76 (19)
O3—C3—C2	122.3 (2)	C12—C13—C18	111.6 (2)
C4—C3—C2	116.9 (2)	C14—C13—C18	113.3 (2)
C5—C4—C3	123.5 (2)	C13—C14—C8	113.47 (18)
C5—C4—H4	118.3	C13—C14—C15	104.54 (17)
C3—C4—H4	118.3	C8—C14—C15	120.6 (2)
C4—C5—C6	120.0 (2)	C13—C14—H14	105.7
C4—C5—C10	122.7 (2)	C8—C14—H14	105.7
C6—C5—C10	117.22 (17)	C15—C14—H14	105.7
C66—C6—C5	122.25 (18)	C14—C15—C16	101.9 (2)
C66—C6—C7	122.3 (2)	C14—C15—H15A	111.4
C5—C6—C7	115.46 (19)	C16—C15—H15A	111.4
C6—C7—C8	112.53 (18)	C14—C15—H15B	111.4
C6—C7—H7A	109.1	C16—C15—H15B	111.4
C8—C7—H7A	109.1	H15A—C15—H15B	109.3
C6—C7—H7B	109.1	C17—C16—C15	106.3 (2)
C8—C7—H7B	109.1	C17—C16—H16A	110.5
H7A—C7—H7B	107.8	C15—C16—H16A	110.5
C7—C8—C14	111.40 (17)	C17—C16—H16B	110.5
C7—C8—C9	109.92 (16)	C15—C16—H16B	110.5
C14—C8—C9	108.45 (18)	H16A—C16—H16B	108.7
C7—C8—H8	109.0	O17—C17—C13	126.4 (3)
C14—C8—H8	109.0	O17—C17—C16	125.3 (2)
C9—C8—H8	109.0	C13—C17—C16	108.3 (2)
C11—C9—C8	112.54 (16)	C13—C18—H18A	109.5
C11—C9—C10	112.90 (17)	C13—C18—H18B	109.5
C8—C9—C10	112.83 (16)	H18A—C18—H18B	109.5
C11—C9—H9	105.9	C13—C18—H18C	109.5
C8—C9—H9	105.9	H18A—C18—H18C	109.5
C10—C9—H9	105.9	H18B—C18—H18C	109.5
C5—C10—C19	107.41 (18)	C10—C19—H19A	109.5
C5—C10—C1	109.70 (17)	C10—C19—H19B	109.5
C19—C10—C1	110.02 (19)	H19A—C19—H19B	109.5
C5—C10—C9	108.90 (16)	C10—C19—H19C	109.5
C19—C10—C9	112.03 (17)	H19A—C19—H19C	109.5
C1—C10—C9	108.75 (16)	H19B—C19—H19C	109.5
C9—C11—C12	113.8 (2)	C6—C66—H66A	120.0
C9—C11—H11A	108.8	C6—C66—H66B	120.0
C12—C11—H11A	108.8	H66A—C66—H66B	120.0
C10—C1—C2—C3	−52.5 (3)	C8—C9—C10—C19	66.5 (2)
C1—C2—C3—O3	−153.9 (3)	C11—C9—C10—C1	59.3 (2)
C1—C2—C3—C4	28.6 (3)	C8—C9—C10—C1	−171.65 (17)
O3—C3—C4—C5	−177.9 (3)	C8—C9—C11—C12	50.9 (3)
C2—C3—C4—C5	−0.4 (4)	C10—C9—C11—C12	−180.0 (2)
C3—C4—C5—C6	172.8 (2)	C9—C11—C12—C13	−53.2 (3)
C3—C4—C5—C10	−4.8 (4)	C11—C12—C13—C17	170.15 (19)
C4—C5—C6—C66	−43.6 (3)	C11—C12—C13—C14	56.5 (3)
C10—C5—C6—C66	134.1 (2)	C11—C12—C13—C18	−69.4 (2)
C4—C5—C6—C7	137.7 (2)	C17—C13—C14—C8	174.9 (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—C8	63.4 (3)
C5—C6—C7—C8	47.7 (3)	C17—C13—C14—C15	41.7 (2)
C6—C7—C8—C14	−174.15 (19)	C12—C13—C14—C15	165.22 (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—C13	178.7 (2)
C14—C8—C9—C11	−51.0 (2)	C9—C8—C14—C13	57.6 (2)
C7—C8—C9—C10	57.8 (2)	C7—C8—C14—C15	−56.3 (3)
C14—C8—C9—C10	179.86 (17)	C9—C8—C14—C15	−177.35 (19)
C4—C5—C10—C19	101.4 (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—C17	21.5 (3)
C6—C5—C10—C1	164.16 (18)	C12—C13—C17—O17	34.0 (4)
C4—C5—C10—C9	−137.1 (2)	C14—C13—C17—O17	152.1 (3)
C6—C5—C10—C9	45.3 (2)	C18—C13—C17—O17	−90.0 (3)
C2—C1—C10—C5	46.0 (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—C9	164.96 (19)	C18—C13—C17—C16	90.0 (3)
C11—C9—C10—C5	178.85 (19)	C15—C16—C17—O17	−176.0 (3)
C8—C9—C10—C5	−52.1 (2)	C15—C16—C17—C13	3.9 (3)
C11—C9—C10—C19	−62.5 (2)	C19—C10—C13—C18	2.2 (2)

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

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) ; (ii) .