Pregna-1,4,9(11),16-tetra­ene-3,20-dione

The title compound, C₂₁H₂₄O₂, contains four rings. The cyclo­hexa­dienone ring is planar, the cyclo­hexane and cyclo­hexene rings adopt chair and sofa conformations, respectively, while the cyclo­pentene ring adopts an envelope conformation. Weak inter­molecular C—H...O hydrogen bonding helps to stabilize the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.039
• wR factor = 0.124
• Data-to-parameter ratio = 10.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT024_ALERT_4_B Merging of Friedel Pairs is STRONGLY Indicated .          !

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           27.40
           From the CIF: _reflns_number_total               2267
           Count of symmetry unique reflns         2261
           Completeness (_total/calc)            100.27%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         6
           Fraction of Friedel pairs measured     0.003
           Are heavy atom types Z>Si present         no
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C8     = .          R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C10    = .          S
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C13    = .          R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of C14    = .          R

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

   6 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia,1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Pregna-1,4,9(11),16-tetraene-3,20-dione

Crystal data

C21H24O2	F(000) = 664
Mr = 308.40	Dx = 1.191 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 12671 reflections
a = 6.6433 (19) Å	θ = 3.2–27.5°
b = 11.278 (4) Å	µ = 0.08 mm^−1
c = 22.951 (8) Å	T = 293 K
V = 1719.6 (10) Å^3	Chunk, colorless
Z = 4	0.42 × 0.36 × 0.32 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	1393 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.036
Graphite monochromator	θmax = 27.4°, θmin = 3.1°
Detector resolution: 10.00 pixels mm^-1	h = −8→8
ω scans	k = −14→14
17000 measured reflections	l = −27→29
2267 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.124	w = 1/[σ^2(Fo^2) + (0.055P)^2 + 0.1715P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max = 0.001
2267 reflections	Δρmax = 0.14 e Å^−3
212 parameters	Δρmin = −0.15 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.026 (3)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.4852 (4)	0.9160 (3)	−0.01135 (9)	0.1169 (9)
O2	0.7845 (4)	0.7254 (2)	0.41831 (10)	0.0966 (8)
C1	0.5076 (5)	0.7236 (3)	0.11068 (13)	0.0802 (9)
H1	0.5851	0.6602	0.1237	0.096*
C2	0.5583 (5)	0.7737 (4)	0.06033 (13)	0.0918 (11)
H2	0.6680	0.7444	0.0397	0.110*
C3	0.4459 (5)	0.8732 (3)	0.03691 (13)	0.0826 (10)
C4	0.2849 (5)	0.9187 (3)	0.07242 (11)	0.0748 (8)
H4	0.2158	0.9857	0.0598	0.090*
C5	0.2308 (4)	0.8687 (2)	0.12273 (11)	0.0627 (7)
C6	0.0610 (5)	0.9184 (3)	0.15841 (11)	0.0797 (9)
H6A	−0.0493	0.8620	0.1593	0.096*
H6B	0.0125	0.9909	0.1406	0.096*
C7	0.1307 (5)	0.9440 (3)	0.22043 (11)	0.0725 (8)
H7A	0.0152	0.9673	0.2436	0.087*
H7B	0.2236	1.0104	0.2197	0.087*
C8	0.2337 (4)	0.8383 (2)	0.24965 (10)	0.0559 (6)
H8	0.1332	0.7764	0.2567	0.067*
C9	0.3984 (4)	0.7883 (2)	0.21085 (10)	0.0548 (6)
C10	0.3353 (4)	0.7620 (2)	0.14763 (11)	0.0602 (7)
C11	0.5823 (4)	0.7677 (2)	0.23091 (11)	0.0628 (7)
H11	0.6783	0.7441	0.2038	0.075*
C12	0.6513 (4)	0.7789 (3)	0.29318 (11)	0.0646 (7)
H12A	0.7303	0.8506	0.2978	0.077*
H12B	0.7357	0.7118	0.3033	0.077*
C13	0.4698 (4)	0.7830 (2)	0.33342 (11)	0.0564 (6)
C14	0.3255 (4)	0.8749 (2)	0.30746 (10)	0.0561 (6)
H14	0.4087	0.9445	0.2988	0.067*
C15	0.1915 (4)	0.9116 (3)	0.35889 (10)	0.0750 (8)
H15A	0.1434	0.9924	0.3548	0.090*
H15B	0.0777	0.8585	0.3636	0.090*
C16	0.3388 (5)	0.8997 (3)	0.40807 (12)	0.0734 (8)
H16	0.3215	0.9352	0.4443	0.088*
C17	0.4965 (4)	0.8331 (2)	0.39434 (11)	0.0618 (7)
C18	0.3747 (5)	0.6592 (2)	0.33910 (12)	0.0712 (8)
H18A	0.4604	0.6095	0.3623	0.107*
H18B	0.3590	0.6249	0.3011	0.107*
H18C	0.2454	0.6659	0.3575	0.107*
C19	0.1861 (6)	0.6556 (3)	0.14813 (12)	0.0845 (9)
H19A	0.0752	0.6733	0.1735	0.127*
H19B	0.2543	0.5859	0.1619	0.127*
H19C	0.1370	0.6420	0.1094	0.127*
C20	0.6632 (5)	0.8013 (3)	0.43314 (12)	0.0708 (8)
C21	0.6834 (6)	0.8645 (3)	0.49060 (12)	0.0943 (11)
H21A	0.8008	0.8361	0.5106	0.141*
H21B	0.5662	0.8495	0.5139	0.141*
H21C	0.6960	0.9482	0.4839	0.141*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.141 (2)	0.144 (2)	0.0650 (12)	−0.033 (2)	0.0217 (15)	0.0112 (14)
O2	0.0909 (15)	0.1037 (18)	0.0952 (15)	0.0217 (15)	−0.0220 (14)	−0.0002 (14)
C1	0.088 (2)	0.086 (2)	0.0671 (17)	0.016 (2)	0.0038 (17)	−0.0126 (16)
C2	0.086 (2)	0.122 (3)	0.0675 (18)	0.000 (2)	0.0159 (18)	−0.021 (2)
C3	0.095 (2)	0.095 (2)	0.0583 (16)	−0.025 (2)	0.0088 (17)	−0.0014 (16)
C4	0.095 (2)	0.0696 (18)	0.0602 (16)	−0.0069 (18)	−0.0014 (16)	0.0056 (14)
C5	0.0662 (16)	0.0642 (17)	0.0576 (14)	−0.0036 (14)	−0.0029 (13)	0.0026 (12)
C6	0.0735 (18)	0.095 (2)	0.0703 (17)	0.0206 (18)	−0.0008 (15)	0.0132 (16)
C7	0.0714 (17)	0.0791 (19)	0.0671 (15)	0.0189 (16)	0.0062 (14)	0.0061 (14)
C8	0.0503 (13)	0.0561 (15)	0.0612 (14)	0.0026 (12)	0.0051 (11)	0.0043 (11)
C9	0.0562 (14)	0.0508 (14)	0.0575 (13)	−0.0027 (12)	0.0067 (12)	0.0012 (11)
C10	0.0632 (14)	0.0580 (15)	0.0595 (14)	−0.0026 (14)	0.0037 (13)	−0.0012 (12)
C11	0.0539 (14)	0.0694 (17)	0.0650 (15)	0.0024 (14)	0.0087 (13)	−0.0038 (13)
C12	0.0530 (14)	0.0700 (17)	0.0707 (16)	0.0022 (14)	0.0010 (13)	−0.0034 (14)
C13	0.0529 (14)	0.0549 (14)	0.0616 (14)	−0.0007 (12)	0.0011 (12)	0.0006 (12)
C14	0.0554 (14)	0.0573 (15)	0.0558 (13)	0.0034 (13)	0.0061 (11)	0.0025 (11)
C15	0.0705 (16)	0.088 (2)	0.0663 (16)	0.0170 (17)	0.0068 (15)	−0.0063 (16)
C16	0.0816 (19)	0.082 (2)	0.0572 (14)	0.0050 (18)	0.0025 (15)	−0.0068 (14)
C17	0.0623 (15)	0.0634 (16)	0.0596 (14)	−0.0023 (15)	−0.0009 (13)	0.0028 (13)
C18	0.0797 (18)	0.0573 (16)	0.0765 (17)	−0.0097 (15)	−0.0049 (16)	0.0080 (13)
C19	0.109 (2)	0.0687 (19)	0.0760 (18)	−0.0273 (19)	−0.0120 (19)	0.0044 (15)
C20	0.0722 (17)	0.0711 (19)	0.0691 (17)	−0.0077 (17)	−0.0046 (15)	0.0062 (15)
C21	0.099 (2)	0.113 (3)	0.0701 (17)	−0.015 (2)	−0.0153 (19)	−0.0038 (18)

Geometric parameters (Å, º)

O1—C3	1.236 (3)	C11—H11	0.9300
O2—C20	1.224 (4)	C12—C13	1.519 (4)
C1—C2	1.330 (4)	C12—H12A	0.9700
C1—C10	1.489 (4)	C12—H12B	0.9700
C1—H1	0.9300	C13—C17	1.518 (4)
C2—C3	1.451 (5)	C13—C14	1.532 (3)
C2—H2	0.9300	C13—C18	1.539 (4)
C3—C4	1.440 (4)	C14—C15	1.535 (3)
C4—C5	1.334 (4)	C14—H14	0.9800
C4—H4	0.9300	C15—C16	1.500 (4)
C5—C10	1.502 (4)	C15—H15A	0.9700
C5—C6	1.502 (4)	C15—H15B	0.9700
C6—C7	1.525 (4)	C16—C17	1.327 (4)
C6—H6A	0.9700	C16—H16	0.9300
C6—H6B	0.9700	C17—C20	1.466 (4)
C7—C8	1.530 (4)	C18—H18A	0.9600
C7—H7A	0.9700	C18—H18B	0.9600
C7—H7B	0.9700	C18—H18C	0.9600
C8—C14	1.517 (3)	C19—H19A	0.9600
C8—C9	1.519 (3)	C19—H19B	0.9600
C8—H8	0.9800	C19—H19C	0.9600
C9—C11	1.326 (4)	C20—C21	1.505 (4)
C9—C10	1.539 (3)	C21—H21A	0.9600
C10—C19	1.556 (4)	C21—H21B	0.9600
C11—C12	1.506 (4)	C21—H21C	0.9600
C2—C1—C10	124.5 (3)	C11—C12—H12B	109.7
C2—C1—H1	117.8	C13—C12—H12B	109.7
C10—C1—H1	117.8	H12A—C12—H12B	108.2
C1—C2—C3	121.4 (3)	C17—C13—C12	118.6 (2)
C1—C2—H2	119.3	C17—C13—C14	100.3 (2)
C3—C2—H2	119.3	C12—C13—C14	106.33 (19)
O1—C3—C4	121.7 (4)	C17—C13—C18	107.9 (2)
O1—C3—C2	121.7 (3)	C12—C13—C18	110.5 (2)
C4—C3—C2	116.6 (3)	C14—C13—C18	112.9 (2)
C5—C4—C3	122.6 (3)	C8—C14—C13	114.1 (2)
C5—C4—H4	118.7	C8—C14—C15	120.8 (2)
C3—C4—H4	118.7	C13—C14—C15	104.25 (19)
C4—C5—C10	122.9 (3)	C8—C14—H14	105.5
C4—C5—C6	121.1 (3)	C13—C14—H14	105.5
C10—C5—C6	116.0 (2)	C15—C14—H14	105.5
C5—C6—C7	110.6 (2)	C16—C15—C14	100.2 (2)
C5—C6—H6A	109.5	C16—C15—H15A	111.7
C7—C6—H6A	109.5	C14—C15—H15A	111.7
C5—C6—H6B	109.5	C16—C15—H15B	111.7
C7—C6—H6B	109.5	C14—C15—H15B	111.7
H6A—C6—H6B	108.1	H15A—C15—H15B	109.5
C6—C7—C8	113.4 (2)	C17—C16—C15	112.8 (2)
C6—C7—H7A	108.9	C17—C16—H16	123.6
C8—C7—H7A	108.9	C15—C16—H16	123.6
C6—C7—H7B	108.9	C16—C17—C20	126.2 (3)
C8—C7—H7B	108.9	C16—C17—C13	109.7 (2)
H7A—C7—H7B	107.7	C20—C17—C13	123.8 (3)
C14—C8—C9	108.9 (2)	C13—C18—H18A	109.5
C14—C8—C7	110.6 (2)	C13—C18—H18B	109.5
C9—C8—C7	110.8 (2)	H18A—C18—H18B	109.5
C14—C8—H8	108.9	C13—C18—H18C	109.5
C9—C8—H8	108.9	H18A—C18—H18C	109.5
C7—C8—H8	108.9	H18B—C18—H18C	109.5
C11—C9—C8	121.7 (2)	C10—C19—H19A	109.5
C11—C9—C10	123.0 (2)	C10—C19—H19B	109.5
C8—C9—C10	115.3 (2)	H19A—C19—H19B	109.5
C1—C10—C5	111.8 (2)	C10—C19—H19C	109.5
C1—C10—C9	112.5 (2)	H19A—C19—H19C	109.5
C5—C10—C9	109.3 (2)	H19B—C19—H19C	109.5
C1—C10—C19	105.7 (2)	O2—C20—C17	120.0 (3)
C5—C10—C19	109.0 (2)	O2—C20—C21	121.1 (3)
C9—C10—C19	108.4 (2)	C17—C20—C21	118.9 (3)
C9—C11—C12	126.5 (2)	C20—C21—H21A	109.5
C9—C11—H11	116.7	C20—C21—H21B	109.5
C12—C11—H11	116.7	H21A—C21—H21B	109.5
C11—C12—C13	109.7 (2)	C20—C21—H21C	109.5
C11—C12—H12A	109.7	H21A—C21—H21C	109.5
C13—C12—H12A	109.7	H21B—C21—H21C	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19C···O1^i	0.96	2.55	3.505 (4)	173
C21—H21B···O2^ii	0.96	2.58	3.524 (5)	170

Symmetry codes: (i) x−1/2, −y+3/2, −z; (ii) x−1/2, −y+3/2, −z+1.