In the title compound, C23H34O4, the two saturated six-membered rings have slightly flattened chair conformations and the unsaturated ring assumes a 8β,9α-half chair conformation distorted towards a 8β-sofa. The five-membered ring has an unusual conformation close to a 13β-envelope. The acetoxy and methyl ketone substituents are twisted with respect to the average molecular plane of the steroid nucleus. The molecules are hydrogen-bonded head-to-head via the hydroxy and methyl ketone groups forming dimers, which are stacked in planes perpendicular to the b axis.
Supporting information
CCDC reference: 170755
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- R factor = 0.041
- wR factor = 0.119
- Data-to-parameter ratio = 10.1
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
General Notes
REFLT_03
From the CIF: _diffrn_reflns_theta_max 27.47
From the CIF: _reflns_number_total 2553
Count of symmetry unique reflns 2612
Completeness (_total/calc) 97.74%
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
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.
16α,17α-Epoxy-20-oxopregn-5-en-3β-yl acetate, required for introduction of
the 16α-hydroxy group, was easily prepared from commercially available
20-oxopregna-5,16-dien-3β-yl acetate through a two-step reaction (Kirk & Sá
e Melo, 1979; Andrade et al., 2001). Synthesis of
16α-hydroxy-20-oxopregn-5-en-3β-yl acetate, (I), was efficiently
accomplished by sonochemical reductive opening of the 16α,17α-epoxy ketone
with aluminium amalgam (Moreno et al., 1993; Moreno, Sá e Melo &
Campos Neves, 1998). The product of this reaction was isolated and identified
as the title compound (I) from IR, 1H and 13C NMR spectroscopy (Moreno
et al., 1993). Crystals suitable for X-ray analysis were obtained by
slow evaporation of a solution of the steroid in methanol.
The H atoms were placed at calculated positions and refined as riding using
SHELXL97 defaults, except for atom H16, involved in hydrogen bonding,
which was refined isotropically with Uiso(H16) =
1.2Ueq(O16). Examination of the crystal structure with PLATON
(Spek, 2001) showed that there are no solvent-accessible voids in the crystal
lattice.
Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.
16
α-Hydroxy-20-oxopregn-5-en-3
β-yl-acetate
top
Crystal data top
C23H34O4 | F(000) = 408 |
Mr = 374.50 | Dx = 1.192 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
a = 12.110 (9) Å | Cell parameters from 25 reflections |
b = 6.084 (3) Å | θ = 6.1–11.3° |
c = 15.024 (11) Å | µ = 0.08 mm−1 |
β = 109.54 (11)° | T = 293 K |
V = 1043.1 (12) Å3 | Plate, colourless |
Z = 2 | 0.48 × 0.25 × 0.12 mm |
Data collection top
Enraf-Nonius CAD-4 diffractometer | Rint = 0.040 |
Radiation source: fine-focus sealed tube | θmax = 27.5°, θmin = 3.4° |
Graphite monochromator | h = −15→15 |
profile data from ω–2θ scans | k = 0→7 |
5099 measured reflections | l = −19→19 |
2553 independent reflections | 3 standard reflections every 180 min |
1631 reflections with I > 2σ(I) | intensity decay: 7.2% |
Refinement top
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.119 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0722P)2] where P = (Fo2 + 2Fc2)/3 |
2553 reflections | (Δ/σ)max < 0.001 |
254 parameters | Δρmax = 0.16 e Å−3 |
1 restraint | Δρmin = −0.19 e Å−3 |
Crystal data top
C23H34O4 | V = 1043.1 (12) Å3 |
Mr = 374.50 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 12.110 (9) Å | µ = 0.08 mm−1 |
b = 6.084 (3) Å | T = 293 K |
c = 15.024 (11) Å | 0.48 × 0.25 × 0.12 mm |
β = 109.54 (11)° | |
Data collection top
Enraf-Nonius CAD-4 diffractometer | Rint = 0.040 |
5099 measured reflections | 3 standard reflections every 180 min |
2553 independent reflections | intensity decay: 7.2% |
1631 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.041 | 1 restraint |
wR(F2) = 0.119 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.16 e Å−3 |
2553 reflections | Δρmin = −0.19 e Å−3 |
254 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 | x | y | z | Uiso*/Ueq | |
C9 | 0.72726 (18) | 0.9296 (5) | 0.52983 (16) | 0.0370 (6) | |
H9 | 0.7127 | 1.0880 | 0.5216 | 0.044* | |
C8 | 0.86126 (19) | 0.9042 (5) | 0.57368 (17) | 0.0387 (6) | |
H8 | 0.8817 | 0.7479 | 0.5768 | 0.046* | |
C14 | 0.90414 (19) | 1.0010 (5) | 0.67236 (17) | 0.0382 (6) | |
H14 | 0.8843 | 1.1576 | 0.6643 | 0.046* | |
O3 | 0.52302 (16) | 0.9422 (4) | 0.12741 (13) | 0.0620 (6) | |
C10 | 0.6767 (2) | 0.8284 (5) | 0.42967 (19) | 0.0397 (6) | |
C7 | 0.9178 (2) | 1.0229 (6) | 0.51097 (18) | 0.0456 (7) | |
H7A | 0.9209 | 1.1788 | 0.5251 | 0.055* | |
H7B | 0.9977 | 0.9711 | 0.5261 | 0.055* | |
C11 | 0.6640 (2) | 0.8537 (5) | 0.59778 (19) | 0.0501 (7) | |
H11A | 0.5815 | 0.8896 | 0.5705 | 0.060* | |
H11B | 0.6706 | 0.6951 | 0.6043 | 0.060* | |
C6 | 0.8552 (2) | 0.9913 (5) | 0.40766 (19) | 0.0476 (7) | |
H6 | 0.895 (2) | 1.043 (6) | 0.361 (2) | 0.057* | |
O16 | 1.09727 (19) | 1.2494 (5) | 0.86089 (16) | 0.0672 (7) | |
H16 | 1.095 (3) | 1.274 (8) | 0.914 (3) | 0.081* | |
C19 | 0.6800 (3) | 0.5757 (5) | 0.4322 (2) | 0.0578 (8) | |
H19A | 0.6293 | 0.5227 | 0.4648 | 0.069* | |
H19B | 0.7586 | 0.5272 | 0.4646 | 0.069* | |
H19C | 0.6540 | 0.5197 | 0.3688 | 0.069* | |
C4 | 0.6937 (2) | 0.8813 (6) | 0.26356 (19) | 0.0543 (8) | |
H4A | 0.6897 | 0.7264 | 0.2475 | 0.065* | |
H4B | 0.7421 | 0.9538 | 0.2324 | 0.065* | |
C13 | 0.8437 (2) | 0.9133 (5) | 0.74062 (19) | 0.0403 (6) | |
C5 | 0.7490 (2) | 0.9080 (5) | 0.36968 (18) | 0.0424 (6) | |
C2 | 0.4964 (2) | 0.8724 (6) | 0.27778 (19) | 0.0545 (8) | |
H2A | 0.4907 | 0.7160 | 0.2643 | 0.065* | |
H2B | 0.4181 | 0.9341 | 0.2545 | 0.065* | |
C12 | 0.7124 (2) | 0.9575 (6) | 0.69538 (18) | 0.0480 (7) | |
H12A | 0.6713 | 0.8982 | 0.7355 | 0.058* | |
H12B | 0.6989 | 1.1148 | 0.6902 | 0.058* | |
C1 | 0.5491 (2) | 0.9090 (6) | 0.38414 (18) | 0.0478 (7) | |
H1A | 0.5005 | 0.8343 | 0.4145 | 0.057* | |
H1B | 0.5464 | 1.0649 | 0.3967 | 0.057* | |
C3 | 0.5714 (2) | 0.9792 (6) | 0.22882 (18) | 0.0525 (7) | |
H3 | 0.5759 | 1.1375 | 0.2416 | 0.063* | |
C20 | 0.8878 (2) | 0.9925 (6) | 0.91855 (18) | 0.0491 (7) | |
C15 | 1.0340 (2) | 0.9922 (6) | 0.73175 (18) | 0.0515 (7) | |
H15A | 1.0782 | 1.0991 | 0.7095 | 0.062* | |
H15B | 1.0659 | 0.8471 | 0.7291 | 0.062* | |
O20 | 0.9438 (2) | 0.8490 (5) | 0.96974 (16) | 0.0725 (7) | |
C17 | 0.9090 (2) | 1.0545 (5) | 0.82861 (18) | 0.0423 (6) | |
H17 | 0.8821 | 1.2063 | 0.8140 | 0.051* | |
C18 | 0.8649 (3) | 0.6684 (5) | 0.7625 (2) | 0.0572 (8) | |
H18A | 0.8411 | 0.5864 | 0.7045 | 0.069* | |
H18B | 0.8202 | 0.6211 | 0.8011 | 0.069* | |
H18C | 0.9467 | 0.6438 | 0.7956 | 0.069* | |
C21 | 0.7945 (3) | 1.1146 (6) | 0.9411 (2) | 0.0607 (9) | |
H21A | 0.7854 | 1.0552 | 0.9974 | 0.073* | |
H21B | 0.7220 | 1.1006 | 0.8896 | 0.073* | |
H21C | 0.8156 | 1.2670 | 0.9507 | 0.073* | |
C16 | 1.0384 (2) | 1.0466 (6) | 0.83213 (19) | 0.0499 (7) | |
H16A | 1.0800 | 0.9297 | 0.8752 | 0.060* | |
C23 | 0.3880 (3) | 1.0067 (10) | −0.0240 (2) | 0.0874 (14) | |
H23A | 0.3152 | 1.0808 | −0.0548 | 0.105* | |
H23B | 0.3760 | 0.8507 | −0.0296 | 0.105* | |
H23C | 0.4444 | 1.0488 | −0.0531 | 0.105* | |
O22 | 0.3948 (3) | 1.2105 (7) | 0.1139 (2) | 0.1163 (13) | |
C22 | 0.4323 (3) | 1.0688 (9) | 0.0778 (3) | 0.0753 (12) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C9 | 0.0340 (11) | 0.0331 (14) | 0.0464 (14) | 0.0012 (11) | 0.0167 (10) | 0.0049 (11) |
C8 | 0.0342 (11) | 0.0366 (14) | 0.0451 (13) | 0.0020 (12) | 0.0130 (9) | −0.0037 (12) |
C14 | 0.0378 (11) | 0.0346 (14) | 0.0448 (13) | 0.0043 (12) | 0.0174 (10) | 0.0012 (12) |
O3 | 0.0536 (11) | 0.0819 (17) | 0.0461 (11) | 0.0083 (12) | 0.0107 (8) | 0.0084 (12) |
C10 | 0.0360 (12) | 0.0372 (15) | 0.0457 (15) | −0.0001 (11) | 0.0131 (11) | 0.0009 (12) |
C7 | 0.0384 (12) | 0.0555 (19) | 0.0476 (14) | −0.0065 (13) | 0.0207 (10) | −0.0053 (14) |
C11 | 0.0378 (12) | 0.0608 (19) | 0.0543 (16) | −0.0037 (14) | 0.0188 (11) | 0.0079 (15) |
C6 | 0.0433 (13) | 0.0574 (18) | 0.0471 (14) | −0.0032 (14) | 0.0219 (11) | −0.0026 (15) |
O16 | 0.0647 (13) | 0.0850 (17) | 0.0560 (13) | −0.0251 (13) | 0.0257 (11) | −0.0247 (13) |
C19 | 0.0650 (18) | 0.0436 (17) | 0.060 (2) | −0.0060 (16) | 0.0153 (15) | −0.0049 (15) |
C4 | 0.0445 (14) | 0.073 (2) | 0.0461 (15) | 0.0047 (15) | 0.0154 (11) | −0.0016 (15) |
C13 | 0.0416 (13) | 0.0353 (14) | 0.0462 (14) | 0.0047 (12) | 0.0177 (11) | 0.0060 (12) |
C5 | 0.0380 (12) | 0.0463 (16) | 0.0452 (14) | 0.0044 (12) | 0.0170 (10) | −0.0013 (13) |
C2 | 0.0383 (12) | 0.070 (2) | 0.0516 (16) | 0.0014 (14) | 0.0097 (11) | 0.0024 (15) |
C12 | 0.0409 (12) | 0.061 (2) | 0.0485 (14) | 0.0010 (14) | 0.0232 (10) | 0.0060 (15) |
C1 | 0.0356 (12) | 0.0598 (18) | 0.0493 (15) | 0.0009 (14) | 0.0159 (10) | 0.0009 (15) |
C3 | 0.0498 (14) | 0.060 (2) | 0.0459 (15) | 0.0027 (15) | 0.0140 (11) | 0.0012 (15) |
C20 | 0.0519 (14) | 0.0553 (18) | 0.0398 (14) | 0.0009 (15) | 0.0150 (11) | 0.0005 (15) |
C15 | 0.0400 (12) | 0.068 (2) | 0.0484 (15) | 0.0018 (15) | 0.0174 (10) | −0.0080 (16) |
O20 | 0.0840 (16) | 0.0777 (18) | 0.0618 (14) | 0.0249 (15) | 0.0324 (11) | 0.0271 (14) |
C17 | 0.0457 (13) | 0.0385 (15) | 0.0446 (14) | 0.0067 (13) | 0.0176 (11) | 0.0041 (12) |
C18 | 0.0724 (19) | 0.0370 (16) | 0.0589 (17) | 0.0031 (15) | 0.0177 (14) | 0.0073 (14) |
C21 | 0.0593 (17) | 0.075 (2) | 0.0552 (17) | 0.0035 (17) | 0.0285 (14) | −0.0040 (17) |
C16 | 0.0441 (13) | 0.0605 (19) | 0.0449 (15) | 0.0038 (14) | 0.0146 (11) | −0.0034 (14) |
C23 | 0.0653 (19) | 0.125 (4) | 0.062 (2) | 0.003 (3) | 0.0077 (15) | 0.029 (3) |
O22 | 0.120 (2) | 0.135 (3) | 0.091 (2) | 0.073 (3) | 0.0321 (17) | 0.028 (2) |
C22 | 0.0548 (19) | 0.103 (3) | 0.066 (2) | 0.017 (2) | 0.0172 (16) | 0.026 (2) |
Geometric parameters (Å, º) top
C9—C11 | 1.538 (4) | C13—C12 | 1.529 (4) |
C9—C8 | 1.541 (3) | C13—C18 | 1.529 (5) |
C9—C10 | 1.550 (4) | C13—C17 | 1.553 (4) |
C9—H9 | 0.9800 | C2—C3 | 1.495 (4) |
C8—C14 | 1.516 (4) | C2—C1 | 1.526 (4) |
C8—C7 | 1.520 (4) | C2—H2A | 0.9700 |
C8—H8 | 0.9800 | C2—H2B | 0.9700 |
C14—C15 | 1.527 (4) | C12—H12A | 0.9700 |
C14—C13 | 1.541 (4) | C12—H12B | 0.9700 |
C14—H14 | 0.9800 | C1—H1A | 0.9700 |
O3—C22 | 1.344 (4) | C1—H1B | 0.9700 |
O3—C3 | 1.455 (4) | C3—H3 | 0.9800 |
C10—C5 | 1.531 (4) | C20—O20 | 1.210 (4) |
C10—C19 | 1.538 (4) | C20—C21 | 1.484 (4) |
C10—C1 | 1.545 (4) | C20—C17 | 1.505 (4) |
C7—C6 | 1.495 (4) | C15—C16 | 1.527 (4) |
C7—H7A | 0.9700 | C15—H15A | 0.9700 |
C7—H7B | 0.9700 | C15—H15B | 0.9700 |
C11—C12 | 1.522 (4) | C17—C16 | 1.551 (4) |
C11—H11A | 0.9700 | C17—H17 | 0.9800 |
C11—H11B | 0.9700 | C18—H18A | 0.9600 |
C6—C5 | 1.321 (4) | C18—H18B | 0.9600 |
C6—H6 | 1.02 (3) | C18—H18C | 0.9600 |
O16—C16 | 1.418 (4) | C21—H21A | 0.9600 |
O16—H16 | 0.82 (4) | C21—H21B | 0.9600 |
C19—H19A | 0.9600 | C21—H21C | 0.9600 |
C19—H19B | 0.9600 | C16—H16A | 0.9800 |
C19—H19C | 0.9600 | C23—C22 | 1.490 (5) |
C4—C5 | 1.517 (4) | C23—H23A | 0.9600 |
C4—C3 | 1.518 (4) | C23—H23B | 0.9600 |
C4—H4A | 0.9700 | C23—H23C | 0.9600 |
C4—H4B | 0.9700 | O22—C22 | 1.187 (5) |
| | | |
C11—C9—C8 | 111.9 (2) | C1—C2—H2A | 109.7 |
C11—C9—C10 | 113.7 (2) | C3—C2—H2B | 109.7 |
C8—C9—C10 | 113.1 (2) | C1—C2—H2B | 109.7 |
C11—C9—H9 | 105.8 | H2A—C2—H2B | 108.2 |
C8—C9—H9 | 105.8 | C11—C12—C13 | 111.3 (2) |
C10—C9—H9 | 105.8 | C11—C12—H12A | 109.4 |
C14—C8—C7 | 110.1 (2) | C13—C12—H12A | 109.4 |
C14—C8—C9 | 110.3 (2) | C11—C12—H12B | 109.4 |
C7—C8—C9 | 108.4 (2) | C13—C12—H12B | 109.4 |
C14—C8—H8 | 109.3 | H12A—C12—H12B | 108.0 |
C7—C8—H8 | 109.3 | C2—C1—C10 | 115.0 (2) |
C9—C8—H8 | 109.3 | C2—C1—H1A | 108.5 |
C8—C14—C15 | 120.4 (2) | C10—C1—H1A | 108.5 |
C8—C14—C13 | 115.6 (2) | C2—C1—H1B | 108.5 |
C15—C14—C13 | 103.0 (2) | C10—C1—H1B | 108.5 |
C8—C14—H14 | 105.5 | H1A—C1—H1B | 107.5 |
C15—C14—H14 | 105.5 | O3—C3—C2 | 110.5 (2) |
C13—C14—H14 | 105.5 | O3—C3—C4 | 107.7 (2) |
C22—O3—C3 | 117.4 (3) | C2—C3—C4 | 110.1 (3) |
C5—C10—C19 | 108.4 (3) | O3—C3—H3 | 109.5 |
C5—C10—C1 | 108.9 (2) | C2—C3—H3 | 109.5 |
C19—C10—C1 | 110.0 (3) | C4—C3—H3 | 109.5 |
C5—C10—C9 | 109.1 (2) | O20—C20—C21 | 121.6 (3) |
C19—C10—C9 | 112.0 (3) | O20—C20—C17 | 121.6 (3) |
C1—C10—C9 | 108.4 (2) | C21—C20—C17 | 116.8 (3) |
C6—C7—C8 | 113.9 (2) | C14—C15—C16 | 105.0 (2) |
C6—C7—H7A | 108.8 | C14—C15—H15A | 110.7 |
C8—C7—H7A | 108.8 | C16—C15—H15A | 110.7 |
C6—C7—H7B | 108.8 | C14—C15—H15B | 110.7 |
C8—C7—H7B | 108.8 | C16—C15—H15B | 110.7 |
H7A—C7—H7B | 107.7 | H15A—C15—H15B | 108.8 |
C12—C11—C9 | 113.4 (2) | C20—C17—C16 | 115.8 (2) |
C12—C11—H11A | 108.9 | C20—C17—C13 | 115.7 (2) |
C9—C11—H11A | 108.9 | C16—C17—C13 | 103.5 (2) |
C12—C11—H11B | 108.9 | C20—C17—H17 | 107.1 |
C9—C11—H11B | 108.9 | C16—C17—H17 | 107.1 |
H11A—C11—H11B | 107.7 | C13—C17—H17 | 107.1 |
C5—C6—C7 | 125.5 (3) | C13—C18—H18A | 109.5 |
C5—C6—H6 | 116.0 (15) | C13—C18—H18B | 109.5 |
C7—C6—H6 | 118.5 (15) | H18A—C18—H18B | 109.5 |
C16—O16—H16 | 106 (3) | C13—C18—H18C | 109.5 |
C10—C19—H19A | 109.5 | H18A—C18—H18C | 109.5 |
C10—C19—H19B | 109.5 | H18B—C18—H18C | 109.5 |
H19A—C19—H19B | 109.5 | C20—C21—H21A | 109.5 |
C10—C19—H19C | 109.5 | C20—C21—H21B | 109.5 |
H19A—C19—H19C | 109.5 | H21A—C21—H21B | 109.5 |
H19B—C19—H19C | 109.5 | C20—C21—H21C | 109.5 |
C5—C4—C3 | 110.9 (2) | H21A—C21—H21C | 109.5 |
C5—C4—H4A | 109.5 | H21B—C21—H21C | 109.5 |
C3—C4—H4A | 109.5 | O16—C16—C15 | 109.7 (3) |
C5—C4—H4B | 109.5 | O16—C16—C17 | 112.5 (3) |
C3—C4—H4B | 109.5 | C15—C16—C17 | 105.8 (2) |
H4A—C4—H4B | 108.1 | O16—C16—H16A | 109.6 |
C12—C13—C18 | 110.0 (3) | C15—C16—H16A | 109.6 |
C12—C13—C14 | 107.3 (2) | C17—C16—H16A | 109.6 |
C18—C13—C14 | 113.4 (2) | C22—C23—H23A | 109.5 |
C12—C13—C17 | 116.0 (2) | C22—C23—H23B | 109.5 |
C18—C13—C17 | 110.8 (2) | H23A—C23—H23B | 109.5 |
C14—C13—C17 | 98.9 (2) | C22—C23—H23C | 109.5 |
C6—C5—C4 | 121.3 (3) | H23A—C23—H23C | 109.5 |
C6—C5—C10 | 122.2 (2) | H23B—C23—H23C | 109.5 |
C4—C5—C10 | 116.5 (2) | O22—C22—O3 | 122.0 (4) |
C3—C2—C1 | 110.0 (2) | O22—C22—C23 | 126.2 (4) |
C3—C2—H2A | 109.7 | O3—C22—C23 | 111.8 (4) |
| | | |
C11—C9—C8—C14 | −48.4 (3) | C9—C11—C12—C13 | −56.6 (3) |
C10—C9—C8—C14 | −178.4 (2) | C18—C13—C12—C11 | −67.2 (3) |
C11—C9—C8—C7 | −169.0 (2) | C14—C13—C12—C11 | 56.6 (3) |
C10—C9—C8—C7 | 61.0 (3) | C17—C13—C12—C11 | 166.0 (2) |
C7—C8—C14—C15 | −61.6 (3) | C3—C2—C1—C10 | −56.4 (4) |
C9—C8—C14—C15 | 178.8 (2) | C5—C10—C1—C2 | 46.8 (4) |
C7—C8—C14—C13 | 173.6 (2) | C19—C10—C1—C2 | −71.8 (4) |
C9—C8—C14—C13 | 54.0 (3) | C9—C10—C1—C2 | 165.5 (3) |
C11—C9—C10—C5 | −177.8 (2) | C22—O3—C3—C2 | 79.1 (4) |
C8—C9—C10—C5 | −48.7 (3) | C22—O3—C3—C4 | −160.6 (3) |
C11—C9—C10—C19 | −57.7 (3) | C1—C2—C3—O3 | 179.0 (3) |
C8—C9—C10—C19 | 71.4 (3) | C1—C2—C3—C4 | 60.2 (4) |
C11—C9—C10—C1 | 63.8 (3) | C5—C4—C3—O3 | −178.5 (3) |
C8—C9—C10—C1 | −167.1 (2) | C5—C4—C3—C2 | −57.9 (4) |
C14—C8—C7—C6 | −161.7 (2) | C8—C14—C15—C16 | −165.4 (3) |
C9—C8—C7—C6 | −41.0 (3) | C13—C14—C15—C16 | −34.8 (3) |
C8—C9—C11—C12 | 51.5 (3) | O20—C20—C17—C16 | −36.5 (4) |
C10—C9—C11—C12 | −178.8 (2) | C21—C20—C17—C16 | 144.0 (3) |
C8—C7—C6—C5 | 13.0 (4) | O20—C20—C17—C13 | 84.9 (3) |
C8—C14—C13—C12 | −57.6 (3) | C21—C20—C17—C13 | −94.6 (3) |
C15—C14—C13—C12 | 168.9 (2) | C12—C13—C17—C20 | 74.9 (3) |
C8—C14—C13—C18 | 64.0 (3) | C18—C13—C17—C20 | −51.5 (3) |
C15—C14—C13—C18 | −69.4 (3) | C14—C13—C17—C20 | −170.8 (2) |
C8—C14—C13—C17 | −178.6 (2) | C12—C13—C17—C16 | −157.4 (2) |
C15—C14—C13—C17 | 48.0 (3) | C18—C13—C17—C16 | 76.3 (3) |
C7—C6—C5—C4 | −179.5 (3) | C14—C13—C17—C16 | −43.0 (3) |
C7—C6—C5—C10 | −1.0 (5) | C14—C15—C16—O16 | −114.3 (3) |
C3—C4—C5—C6 | −129.7 (3) | C14—C15—C16—C17 | 7.2 (3) |
C3—C4—C5—C10 | 51.7 (4) | C20—C17—C16—O16 | −89.8 (3) |
C19—C10—C5—C6 | −103.8 (3) | C13—C17—C16—O16 | 142.5 (2) |
C1—C10—C5—C6 | 136.6 (3) | C20—C17—C16—C15 | 150.4 (3) |
C9—C10—C5—C6 | 18.4 (4) | C13—C17—C16—C15 | 22.7 (3) |
C19—C10—C5—C4 | 74.8 (3) | C3—O3—C22—O22 | 2.4 (5) |
C1—C10—C5—C4 | −44.8 (3) | C3—O3—C22—C23 | −177.4 (3) |
C9—C10—C5—C4 | −163.0 (2) | C19—C10—C13—C18 | 3.4 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O16—H16···O20i | 0.82 (4) | 2.01 (4) | 2.817 (4) | 169 (3) |
Symmetry code: (i) −x+2, y+1/2, −z+2. |
Experimental details
Crystal data |
Chemical formula | C23H34O4 |
Mr | 374.50 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 293 |
a, b, c (Å) | 12.110 (9), 6.084 (3), 15.024 (11) |
β (°) | 109.54 (11) |
V (Å3) | 1043.1 (12) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.48 × 0.25 × 0.12 |
|
Data collection |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5099, 2553, 1631 |
Rint | 0.040 |
(sin θ/λ)max (Å−1) | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.119, 1.00 |
No. of reflections | 2553 |
No. of parameters | 254 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.19 |
Selected geometric parameters (Å, º) topC10—C5 | 1.531 (4) | C4—C5 | 1.517 (4) |
C6—C5 | 1.321 (4) | O22—C22 | 1.187 (5) |
| | | |
O20—C20—C17—C13 | 84.9 (3) | C3—O3—C22—O22 | 2.4 (5) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O16—H16···O20i | 0.82 (4) | 2.01 (4) | 2.817 (4) | 169 (3) |
Symmetry code: (i) −x+2, y+1/2, −z+2. |
As part of an ongoing project to clarify the behaviour of steroidal 16α,17α-epoxy ketones towards reactions with broad scope in the synthesis of bioactive steroids (Moreno, Costa et al., 1998), 16α-hydroxy-20-oxopregn-5-en-3β-yl acetate, (I), was prepared from the corresponding 16α,17α-epoxide by selective reductive opening with aluminium amalgam under ultrasonic conditions (Moreno et al., 1993; Moreno, Sá e Melo & Campos Neves, 1998). A comparative structural study of the steroidal 16α-hydroxy and 16α,17α-epoxy ketones with those functionalized at C21 or C15 is relevant for the purpose of correlating the observed differences in chemical reactivity (Moreno et al., 1993) with the effects of the stereochemistry of the substituents on molecular conformation.
The X-ray diffraction study of the title compound indicates that all rings are fused trans. An ORTEPII (Johnson, 1976) drawing of the molecule with the corresponding atomic numbering scheme and ring labels is shown in Fig. 1. Bond lengths and angles are within the range of expected values (Allen et al., 1987), with averages Csp3—Csp3 1.532 (4), Csp3—Csp2 1.504 (7) and Csp2—Csp2 1.321 (4) Å, except for a larger than ususal Csp2—Csp3 bond, i.e. C5—C10 [1.531 (4) Å].
Rings A and C have slightly flattened chair conformations, the mean values of their torsion angles being 53 (3) and 53.9 (15)°, respectively. As reported in a previous crystallographic work on the closely related 16α,17α-epoxy derivative (Andrade et al., 2001), the acetoxy group bonded to C3 does not disturb the usual chair conformation of the A ring of the steroid nucleus. The 3β-acetoxy group is planar and oriented equatorially. The dihedral angle between the acetoxy group and the mean molecular plane is 57.2 (2)°, showing that it is twisted around the C3—O3 bond. Due to the double C5═C6 bond, the environment of the C5 atom is planar [sum of the valence angles around C5 is 360.0 (5)°]. Consequently, ring B is highly distorted assuming an 8β,9α-half chair conformation distorted towards a 8β-sofa [asymmetry parameters (Duax & Norton, 1975) are ΔC2(5,6) = 6.7 (4), ΔCS(6) = 16.3 (3) and ΔC2 = 47.8 (4)°]. The five-membered D ring assumes an unusual conformation close to 13β-envelope, with puckering parameters (Cremer & Pople, 1975) q2 = 0.483 (3) Å, ϕ2 = 188.2 (4)° [pseudo-rotation (Altona et al., 1968) and asymmetry parameters (Duax & Norton, 1975): Δ = 18.5 (6)°, ϕm = 48.7 (2)°, ΔCs(13) = 9.3 (3) and ΔC2(13,14) = 12.4 (4)°].
The conformation of the substituent group at C17 is characterized by a torsion angle C13—C17—C20—-O20 of 84.9 (3)°, slightly lower, but close to the values reported by Weeks et al. (1973) in a comparative study of six corticosteroids with a similar side chain at C17. The 17β-methyl ketone group is not coplanar with the mean molecular plane, the dihedral angle being 55.59 (14)°. The pseudo-torsion angle C19—C10—C13—C18 which measures the twist of the molecule is 3.4 (3)°, much smaller than the twist observed in the 16α,17α-epoxy steroid molecule [10.4 (2)°]. The linear dimension of the molecule given by the distance between terminal C21 and C23 atoms [13.680 (14) Å] is slightly smaller in the hydroxy- than in the epoxy-substituted steroid molecule [14.873 (4) Å].
The molecules are hydrogen bonded head-to-head via the hydroxy and methyl ketone groups. No weak C—H···O short contacts with suitable geometry to be classified as weak intermolecular interactions are found in the structure. Interestingly, the carbonyl O22 atom of the 3β-acetoxy group, which is a potential strong acceptor, is not involved in hydrogen bonding. This may be the reason of an increased librational motion or slight disorder of this atom, deduced from the enhanced displacement parameters of O22 when compared to those of neighbour atoms.
It should be stated that the absolute configuration of the molecule was not determined from the X-ray data but was chosen to give the correct chirality that was known beforehand from the synthesis route (Moreno et al., 1993).