Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101002980/fr1302sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101002980/fr1302Isup2.hkl |
CCDC reference: 164679
For related literature, see: Borthwick (1980); Lalancette et al. (1990, 1997, 1998); Leiserowitz (1976); Steiner (1997); Steiner & Desiraju (1998).
Compound (I) was purchased as the (-)-enantiomer from Steraloids Inc., Newport, RI, USA. Crystals of the hydrate, obtained from acetone, lose water at a temperature-dependent rate, giving the anhydrous form, mp. 440 K.
All C-bonded H atoms were found in electron-density difference maps but were placed in calculated positions with C—H 0.96–0.98 Å and Uiso = 1.2Ueq(C), and allowed to refine as riding models. The H atoms on the disordered carboxyl group were also found in difference maps. Their occupancies were fixed at 50%, and they were allowed to ride on their respective oxygen atoms. The water oxygen was refined to an occupancy of 50 (1)%, and subsequently this occupancy was fixed at exactly 50%; a single H atom on the partial water of hydration was placed in an arbitrary position 0.85 Å from the water oxygen on a vector toward the O2 ketone oxygen in the steroid. Its occupancy also was fixed at 50%, and it refined to an hydrogen-O distance of 0.80 Å. The 2nd H atom on the partial occupancy water was not found and therefore the atom count from the data is not the same as the chemical formula sum.
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXP97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97.
C24H36O4·0.5H2O | F(000) = 880 |
Mr = 397.56 | Dx = 1.178 Mg m−3 |
Monoclinic, C2 | Mo Kα radiation, λ = 0.71073 Å |
a = 13.144 (3) Å | Cell parameters from 35 reflections |
b = 7.750 (2) Å | θ = 5.3–13.2° |
c = 22.415 (5) Å | µ = 0.08 mm−1 |
β = 100.87 (1)° | T = 293 K |
V = 2242.4 (9) Å3 | Parallelepiped, colourless |
Z = 4 | 0.65 × 0.60 × 0.10 mm |
Siemens P4 diffractometer | Rint = 0.050 |
Radiation source: normal-focus sealed tube | θmax = 25.0°, θmin = 1.9° |
Graphite monochromator | h = −15→15 |
2θ/θ scans | k = −9→9 |
4412 measured reflections | l = −26→26 |
2127 independent reflections | 3 standard reflections every 97 reflections |
1191 reflections with I > 2σ(I) | intensity decay: variation <1% |
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)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.109 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0385P)2] where P = (Fo2 + 2Fc2)/3 |
2127 reflections | (Δ/σ)max < 0.001 |
265 parameters | Δρmax = 0.11 e Å−3 |
1 restraint | Δρmin = −0.13 e Å−3 |
C24H36O4·0.5H2O | V = 2242.4 (9) Å3 |
Mr = 397.56 | Z = 4 |
Monoclinic, C2 | Mo Kα radiation |
a = 13.144 (3) Å | µ = 0.08 mm−1 |
b = 7.750 (2) Å | T = 293 K |
c = 22.415 (5) Å | 0.65 × 0.60 × 0.10 mm |
β = 100.87 (1)° |
Siemens P4 diffractometer | Rint = 0.050 |
4412 measured reflections | 3 standard reflections every 97 reflections |
2127 independent reflections | intensity decay: variation <1% |
1191 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.050 | 1 restraint |
wR(F2) = 0.109 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 0.11 e Å−3 |
2127 reflections | Δρmin = −0.13 e Å−3 |
265 parameters |
Experimental. 'Crystal mounted on glass fiber using epoxy resin' |
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 | Occ. (<1) | |
O1 | 0.8596 (3) | 0.3116 (7) | 0.53757 (19) | 0.1304 (19) | |
O2 | 0.9159 (3) | −0.0649 (5) | 0.33975 (18) | 0.0925 (12) | |
O3 | 0.1041 (3) | 0.3698 (5) | 0.0202 (2) | 0.1261 (19) | |
O4 | 0.1023 (3) | 0.6483 (5) | 0.01384 (19) | 0.0954 (13) | |
O5 | 1.0727 (7) | −0.1311 (15) | 0.4463 (5) | 0.169 (4) | 0.50 |
C1 | 0.8914 (4) | 0.5175 (7) | 0.4034 (2) | 0.0715 (15) | |
C2 | 0.8304 (4) | 0.5062 (9) | 0.4538 (3) | 0.0912 (19) | |
C3 | 0.8411 (4) | 0.3329 (10) | 0.4829 (3) | 0.091 (2) | |
C4 | 0.8252 (4) | 0.1826 (8) | 0.4396 (2) | 0.0875 (19) | |
C5 | 0.8844 (4) | 0.2010 (6) | 0.3868 (2) | 0.0606 (14) | |
C6 | 0.8571 (4) | 0.0540 (6) | 0.3428 (2) | 0.0657 (15) | |
C7 | 0.7519 (4) | 0.0625 (6) | 0.3024 (2) | 0.0659 (14) | |
C8 | 0.7318 (3) | 0.2367 (6) | 0.2716 (2) | 0.0496 (12) | |
C9 | 0.7560 (3) | 0.3874 (6) | 0.31661 (19) | 0.0496 (11) | |
C10 | 0.8684 (3) | 0.3778 (6) | 0.3542 (2) | 0.0518 (12) | |
C11 | 0.7294 (3) | 0.5614 (6) | 0.2851 (2) | 0.0627 (14) | |
C12 | 0.6179 (3) | 0.5697 (6) | 0.2475 (2) | 0.0632 (14) | |
C13 | 0.5952 (3) | 0.4222 (5) | 0.20128 (19) | 0.0466 (12) | |
C14 | 0.6197 (3) | 0.2538 (6) | 0.2373 (2) | 0.0504 (12) | |
C15 | 0.5754 (4) | 0.1133 (6) | 0.1929 (2) | 0.0624 (13) | |
C16 | 0.4749 (3) | 0.1965 (6) | 0.1575 (2) | 0.0626 (14) | |
C17 | 0.4797 (3) | 0.3915 (6) | 0.1728 (2) | 0.0547 (12) | |
C18 | 0.6600 (3) | 0.4417 (6) | 0.15139 (19) | 0.0614 (14) | |
C19 | 0.9489 (3) | 0.3947 (7) | 0.31378 (19) | 0.0641 (13) | |
C20 | 0.4279 (3) | 0.5026 (6) | 0.1186 (2) | 0.0570 (12) | |
C21 | 0.4376 (4) | 0.6953 (7) | 0.1324 (3) | 0.0812 (17) | |
C22 | 0.3125 (3) | 0.4537 (7) | 0.0994 (2) | 0.0701 (15) | |
C23 | 0.2649 (3) | 0.5158 (7) | 0.0359 (2) | 0.0740 (15) | |
C24 | 0.1498 (3) | 0.5087 (8) | 0.0218 (2) | 0.0649 (13) | |
H3 | 0.0414 | 0.3864 | 0.0119 | 0.080* | 0.50 |
H4 | 0.0398 | 0.6298 | 0.0063 | 0.080* | 0.50 |
HO5A | 1.0391 | −0.1401 | 0.4126 | 0.080* | 0.50 |
H1A | 0.9645 | 0.5123 | 0.4213 | 0.086* | |
H1B | 0.8784 | 0.6293 | 0.3840 | 0.086* | |
H2A | 0.8547 | 0.5937 | 0.4840 | 0.109* | |
H2B | 0.7578 | 0.5285 | 0.4374 | 0.109* | |
H4A | 0.7518 | 0.1712 | 0.4230 | 0.105* | |
H4B | 0.8476 | 0.0777 | 0.4618 | 0.105* | |
H5A | 0.9584 | 0.1908 | 0.4042 | 0.073* | |
H7A | 0.6992 | 0.0405 | 0.3265 | 0.079* | |
H7B | 0.7467 | −0.0269 | 0.2717 | 0.079* | |
H8A | 0.7774 | 0.2470 | 0.2419 | 0.060* | |
H9A | 0.7095 | 0.3743 | 0.3457 | 0.060* | |
H11A | 0.7781 | 0.5842 | 0.2585 | 0.075* | |
H11B | 0.7377 | 0.6516 | 0.3157 | 0.075* | |
H12A | 0.5689 | 0.5645 | 0.2748 | 0.076* | |
H12B | 0.6083 | 0.6791 | 0.2261 | 0.076* | |
H14A | 0.5765 | 0.2551 | 0.2685 | 0.060* | |
H15A | 0.5604 | 0.0098 | 0.2140 | 0.075* | |
H15B | 0.6227 | 0.0847 | 0.1659 | 0.075* | |
H16A | 0.4699 | 0.1795 | 0.1142 | 0.075* | |
H16B | 0.4148 | 0.1444 | 0.1696 | 0.075* | |
H17A | 0.4400 | 0.4086 | 0.2051 | 0.066* | |
H18A | 0.6433 | 0.5491 | 0.1305 | 0.074* | |
H18B | 0.6448 | 0.3481 | 0.1230 | 0.074* | |
H18C | 0.7323 | 0.4400 | 0.1694 | 0.074* | |
H19A | 0.9374 | 0.3070 | 0.2830 | 0.077* | |
H19B | 1.0170 | 0.3815 | 0.3379 | 0.077* | |
H19C | 0.9431 | 0.5064 | 0.2949 | 0.077* | |
H20A | 0.4624 | 0.4787 | 0.0843 | 0.068* | |
H21A | 0.5081 | 0.7310 | 0.1344 | 0.097* | |
H21B | 0.4174 | 0.7178 | 0.1707 | 0.097* | |
H21C | 0.3933 | 0.7585 | 0.1009 | 0.097* | |
H22A | 0.3058 | 0.3292 | 0.1010 | 0.084* | |
H22B | 0.2742 | 0.5031 | 0.1283 | 0.084* | |
H23A | 0.2866 | 0.6339 | 0.0313 | 0.089* | |
H23B | 0.2917 | 0.4459 | 0.0065 | 0.089* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.113 (3) | 0.209 (6) | 0.063 (3) | −0.049 (3) | 0.002 (2) | 0.012 (3) |
O2 | 0.094 (3) | 0.053 (2) | 0.120 (3) | 0.012 (2) | −0.007 (2) | 0.009 (2) |
O3 | 0.053 (2) | 0.076 (3) | 0.242 (6) | −0.003 (2) | 0.010 (3) | −0.003 (3) |
O4 | 0.049 (2) | 0.087 (3) | 0.143 (4) | 0.008 (2) | 0.000 (2) | 0.006 (3) |
O5 | 0.127 (7) | 0.159 (10) | 0.181 (9) | 0.023 (8) | −0.072 (6) | −0.006 (9) |
C1 | 0.066 (3) | 0.070 (4) | 0.070 (3) | −0.002 (3) | −0.010 (3) | 0.002 (3) |
C2 | 0.087 (4) | 0.109 (5) | 0.078 (4) | 0.007 (4) | 0.016 (3) | −0.028 (4) |
C3 | 0.075 (4) | 0.132 (6) | 0.063 (4) | −0.010 (4) | 0.009 (3) | 0.005 (4) |
C4 | 0.088 (4) | 0.092 (5) | 0.081 (4) | −0.010 (4) | 0.012 (3) | 0.026 (4) |
C5 | 0.053 (3) | 0.061 (3) | 0.064 (3) | 0.002 (3) | 0.002 (2) | 0.017 (3) |
C6 | 0.078 (4) | 0.037 (3) | 0.078 (4) | −0.002 (3) | 0.006 (3) | 0.020 (3) |
C7 | 0.068 (3) | 0.043 (3) | 0.081 (3) | 0.001 (3) | 0.000 (3) | 0.011 (3) |
C8 | 0.049 (3) | 0.038 (3) | 0.062 (3) | −0.001 (2) | 0.012 (2) | 0.004 (2) |
C9 | 0.052 (3) | 0.039 (3) | 0.057 (3) | −0.002 (2) | 0.008 (2) | 0.003 (3) |
C10 | 0.046 (3) | 0.050 (3) | 0.056 (3) | −0.003 (2) | 0.002 (2) | 0.002 (3) |
C11 | 0.059 (3) | 0.047 (3) | 0.075 (3) | −0.001 (2) | −0.006 (3) | −0.008 (3) |
C12 | 0.055 (3) | 0.046 (3) | 0.082 (4) | 0.008 (2) | −0.002 (3) | −0.004 (3) |
C13 | 0.043 (3) | 0.044 (3) | 0.053 (3) | 0.001 (2) | 0.010 (2) | 0.000 (2) |
C14 | 0.048 (3) | 0.048 (3) | 0.057 (3) | 0.000 (2) | 0.012 (2) | −0.003 (3) |
C15 | 0.065 (3) | 0.047 (3) | 0.075 (3) | −0.009 (3) | 0.012 (3) | −0.005 (3) |
C16 | 0.050 (3) | 0.058 (3) | 0.078 (3) | −0.010 (3) | 0.007 (2) | 0.000 (3) |
C17 | 0.042 (2) | 0.064 (3) | 0.059 (3) | 0.003 (3) | 0.010 (2) | −0.005 (3) |
C18 | 0.049 (3) | 0.063 (3) | 0.071 (3) | −0.004 (2) | 0.009 (2) | 0.011 (3) |
C19 | 0.051 (3) | 0.063 (3) | 0.077 (3) | −0.004 (3) | 0.007 (2) | 0.006 (3) |
C20 | 0.041 (2) | 0.059 (3) | 0.069 (3) | 0.000 (2) | 0.005 (2) | −0.004 (3) |
C21 | 0.073 (4) | 0.066 (4) | 0.093 (4) | 0.016 (3) | −0.011 (3) | −0.007 (3) |
C22 | 0.046 (3) | 0.082 (4) | 0.078 (3) | 0.004 (3) | 0.000 (2) | 0.001 (3) |
C23 | 0.040 (3) | 0.093 (4) | 0.084 (3) | −0.003 (3) | −0.001 (2) | 0.004 (4) |
C24 | 0.044 (3) | 0.077 (4) | 0.068 (3) | 0.002 (3) | −0.005 (2) | −0.001 (3) |
O1—C3 | 1.214 (6) | C1—H1B | 0.9700 |
O2—C6 | 1.213 (5) | C2—H2A | 0.9700 |
O3—C24 | 1.230 (6) | C2—H2B | 0.9700 |
O4—C24 | 1.246 (6) | C4—H4A | 0.9700 |
C1—C2 | 1.505 (7) | C4—H4B | 0.9700 |
C1—C10 | 1.534 (6) | C5—H5A | 0.9800 |
C2—C3 | 1.488 (8) | C7—H7A | 0.9700 |
C3—C4 | 1.507 (8) | C7—H7B | 0.9700 |
C4—C5 | 1.540 (7) | C8—H8A | 0.9800 |
C5—C6 | 1.506 (7) | C9—H9A | 0.9800 |
C5—C10 | 1.548 (6) | C11—H11A | 0.9700 |
C6—C7 | 1.504 (6) | C11—H11B | 0.9700 |
C7—C8 | 1.517 (6) | C12—H12A | 0.9700 |
C8—C14 | 1.533 (6) | C12—H12B | 0.9700 |
C8—C9 | 1.538 (6) | C14—H14A | 0.9800 |
C9—C11 | 1.532 (6) | C15—H15A | 0.9700 |
C9—C10 | 1.558 (6) | C15—H15B | 0.9700 |
C10—C19 | 1.524 (6) | C16—H16A | 0.9700 |
C11—C12 | 1.548 (5) | C16—H16B | 0.9700 |
C12—C13 | 1.534 (6) | C17—H17A | 0.9800 |
C13—C18 | 1.535 (5) | C18—H18A | 0.9600 |
C13—C14 | 1.536 (6) | C18—H18B | 0.9600 |
C13—C17 | 1.551 (5) | C18—H18C | 0.9600 |
C14—C15 | 1.515 (6) | C19—H19A | 0.9600 |
C15—C16 | 1.548 (6) | C19—H19B | 0.9600 |
C16—C17 | 1.548 (7) | C19—H19C | 0.9600 |
C17—C20 | 1.539 (6) | C20—H20A | 0.9800 |
C20—C21 | 1.526 (7) | C21—H21A | 0.9600 |
C20—C22 | 1.544 (5) | C21—H21B | 0.9600 |
C22—C23 | 1.522 (6) | C21—H21C | 0.9600 |
C23—C24 | 1.486 (6) | C22—H22A | 0.9700 |
O3—H3 | 0.8200 | C22—H22B | 0.9700 |
O4—H4 | 0.8200 | C23—H23A | 0.9700 |
O5—HO5A | 0.8037 | C23—H23B | 0.9700 |
C1—H1A | 0.9700 | ||
C2—C1—C10 | 115.9 (4) | C6—C7—H7A | 109.2 |
C3—C2—C1 | 111.2 (5) | C8—C7—H7A | 109.2 |
O1—C3—C2 | 123.4 (7) | C6—C7—H7B | 109.2 |
O1—C3—C4 | 121.5 (7) | C8—C7—H7B | 109.2 |
C2—C3—C4 | 115.1 (5) | H7A—C7—H7B | 107.9 |
C3—C4—C5 | 113.3 (5) | C7—C8—H8A | 107.8 |
C6—C5—C4 | 109.9 (4) | C14—C8—H8A | 107.8 |
C6—C5—C10 | 111.5 (4) | C9—C8—H8A | 107.8 |
C4—C5—C10 | 113.6 (4) | C11—C9—H9A | 106.3 |
O2—C6—C7 | 121.5 (5) | C8—C9—H9A | 106.3 |
O2—C6—C5 | 122.4 (5) | C10—C9—H9A | 106.3 |
C7—C6—C5 | 116.1 (5) | C9—C11—H11A | 108.9 |
C6—C7—C8 | 112.0 (4) | C12—C11—H11A | 108.9 |
C7—C8—C14 | 111.9 (4) | C9—C11—H11B | 108.9 |
C7—C8—C9 | 112.3 (3) | C12—C11—H11B | 108.9 |
C14—C8—C9 | 108.9 (3) | H11A—C11—H11B | 107.7 |
C11—C9—C8 | 111.4 (3) | C13—C12—H12A | 109.1 |
C11—C9—C10 | 113.7 (4) | C11—C12—H12A | 109.1 |
C8—C9—C10 | 112.2 (4) | C13—C12—H12B | 109.1 |
C19—C10—C1 | 107.6 (4) | C11—C12—H12B | 109.1 |
C19—C10—C5 | 108.0 (4) | H12A—C12—H12B | 107.9 |
C1—C10—C5 | 107.1 (4) | C15—C14—H14A | 105.9 |
C19—C10—C9 | 111.5 (4) | C8—C14—H14A | 105.9 |
C1—C10—C9 | 113.2 (4) | C13—C14—H14A | 105.9 |
C5—C10—C9 | 109.2 (4) | C14—C15—H15A | 111.2 |
C9—C11—C12 | 113.5 (4) | C16—C15—H15A | 111.2 |
C13—C12—C11 | 112.4 (4) | C14—C15—H15B | 111.2 |
C12—C13—C18 | 110.8 (4) | C16—C15—H15B | 111.2 |
C12—C13—C14 | 106.5 (3) | H15A—C15—H15B | 109.1 |
C18—C13—C14 | 112.1 (4) | C17—C16—H16A | 110.2 |
C12—C13—C17 | 116.3 (4) | C15—C16—H16A | 110.2 |
C18—C13—C17 | 110.4 (4) | C17—C16—H16B | 110.2 |
C14—C13—C17 | 100.2 (3) | C15—C16—H16B | 110.2 |
C15—C14—C8 | 118.7 (4) | H16A—C16—H16B | 108.5 |
C15—C14—C13 | 104.4 (3) | C20—C17—H17A | 106.9 |
C8—C14—C13 | 115.0 (4) | C16—C17—H17A | 106.9 |
C14—C15—C16 | 102.8 (4) | C13—C17—H17A | 106.9 |
C17—C16—C15 | 107.3 (4) | C13—C18—H18A | 109.5 |
C20—C17—C16 | 112.2 (4) | C13—C18—H18B | 109.5 |
C20—C17—C13 | 119.5 (4) | H18A—C18—H18B | 109.5 |
C16—C17—C13 | 103.7 (3) | C13—C18—H18C | 109.5 |
C21—C20—C17 | 112.3 (4) | H18A—C18—H18C | 109.5 |
C21—C20—C22 | 109.7 (4) | H18B—C18—H18C | 109.5 |
C17—C20—C22 | 110.3 (4) | C10—C19—H19A | 109.5 |
C23—C22—C20 | 113.1 (4) | C10—C19—H19B | 109.5 |
C24—C23—C22 | 114.2 (4) | H19A—C19—H19B | 109.5 |
O3—C24—O4 | 121.8 (4) | C10—C19—H19C | 109.5 |
O3—C24—C23 | 120.7 (5) | H19A—C19—H19C | 109.5 |
O4—C24—C23 | 117.4 (5) | H19B—C19—H19C | 109.5 |
C24—O3—H3 | 109.5 | C21—C20—H20A | 108.2 |
C24—O4—H4 | 109.5 | C17—C20—H20A | 108.2 |
C2—C1—H1A | 108.3 | C22—C20—H20A | 108.2 |
C10—C1—H1A | 108.3 | C20—C21—H21A | 109.5 |
C2—C1—H1B | 108.3 | C20—C21—H21B | 109.5 |
C10—C1—H1B | 108.3 | H21A—C21—H21B | 109.5 |
H1A—C1—H1B | 107.4 | C20—C21—H21C | 109.5 |
C3—C2—H2A | 109.4 | H21A—C21—H21C | 109.5 |
C1—C2—H2A | 109.4 | H21B—C21—H21C | 109.5 |
C3—C2—H2B | 109.4 | C23—C22—H22A | 109.0 |
C1—C2—H2B | 109.4 | C20—C22—H22A | 109.0 |
H2A—C2—H2B | 108.0 | C23—C22—H22B | 109.0 |
C3—C4—H4A | 108.9 | C20—C22—H22B | 109.0 |
C5—C4—H4A | 108.9 | H22A—C22—H22B | 107.8 |
C3—C4—H4B | 108.9 | C24—C23—H23A | 108.7 |
C5—C4—H4B | 108.9 | C22—C23—H23A | 108.7 |
H4A—C4—H4B | 107.7 | C24—C23—H23B | 108.7 |
C6—C5—H5A | 107.2 | C22—C23—H23B | 108.7 |
C4—C5—H5A | 107.2 | H23A—C23—H23B | 107.6 |
C10—C5—H5A | 107.2 | ||
C10—C1—C2—C3 | 54.3 (6) | C10—C9—C11—C12 | 179.6 (4) |
C1—C2—C3—O1 | 133.0 (5) | C9—C11—C12—C13 | −54.0 (6) |
C1—C2—C3—C4 | −48.1 (6) | C11—C12—C13—C18 | −67.5 (5) |
O1—C3—C4—C5 | −134.2 (5) | C11—C12—C13—C14 | 54.7 (5) |
C2—C3—C4—C5 | 46.9 (7) | C11—C12—C13—C17 | 165.4 (4) |
C3—C4—C5—C6 | −175.0 (5) | C7—C8—C14—C15 | −51.5 (6) |
C3—C4—C5—C10 | −49.3 (6) | C9—C8—C14—C15 | −176.3 (4) |
C4—C5—C6—O2 | −105.3 (6) | C7—C8—C14—C13 | −176.1 (4) |
C10—C5—C6—O2 | 127.8 (5) | C9—C8—C14—C13 | 59.1 (5) |
C4—C5—C6—C7 | 74.6 (5) | C12—C13—C14—C15 | 168.6 (4) |
C10—C5—C6—C7 | −52.3 (5) | C18—C13—C14—C15 | −70.1 (4) |
O2—C6—C7—C8 | −130.5 (5) | C17—C13—C14—C15 | 47.0 (4) |
C5—C6—C7—C8 | 49.6 (6) | C12—C13—C14—C8 | −59.6 (4) |
C6—C7—C8—C14 | −172.4 (4) | C18—C13—C14—C8 | 61.7 (5) |
C6—C7—C8—C9 | −49.5 (5) | C17—C13—C14—C8 | 178.9 (4) |
C7—C8—C9—C11 | −176.8 (4) | C8—C14—C15—C16 | −166.9 (4) |
C14—C8—C9—C11 | −52.2 (5) | C13—C14—C15—C16 | −37.2 (4) |
C7—C8—C9—C10 | 54.4 (5) | C14—C15—C16—C17 | 12.9 (5) |
C14—C8—C9—C10 | 179.0 (4) | C15—C16—C17—C20 | 146.0 (4) |
C2—C1—C10—C19 | −171.2 (4) | C15—C16—C17—C13 | 15.6 (5) |
C2—C1—C10—C5 | −55.3 (5) | C12—C13—C17—C20 | 82.5 (5) |
C2—C1—C10—C9 | 65.1 (6) | C18—C13—C17—C20 | −44.8 (5) |
C6—C5—C10—C19 | −68.0 (5) | C14—C13—C17—C20 | −163.2 (4) |
C4—C5—C10—C19 | 167.1 (4) | C12—C13—C17—C16 | −151.7 (4) |
C6—C5—C10—C1 | 176.4 (4) | C18—C13—C17—C16 | 81.0 (4) |
C4—C5—C10—C1 | 51.5 (5) | C14—C13—C17—C16 | −37.4 (4) |
C6—C5—C10—C9 | 53.5 (5) | C16—C17—C20—C21 | −177.0 (4) |
C4—C5—C10—C9 | −71.4 (5) | C13—C17—C20—C21 | −55.3 (5) |
C11—C9—C10—C19 | −63.9 (5) | C16—C17—C20—C22 | 60.4 (5) |
C8—C9—C10—C19 | 63.6 (5) | C13—C17—C20—C22 | −177.9 (4) |
C11—C9—C10—C1 | 57.5 (5) | C21—C20—C22—C23 | 73.4 (6) |
C8—C9—C10—C1 | −174.9 (4) | C17—C20—C22—C23 | −162.4 (4) |
C11—C9—C10—C5 | 176.8 (4) | C20—C22—C23—C24 | −166.1 (5) |
C8—C9—C10—C5 | −55.7 (5) | C22—C23—C24—O3 | −63.8 (7) |
C8—C9—C11—C12 | 51.7 (5) | C22—C23—C24—O4 | 113.8 (6) |
Experimental details
Crystal data | |
Chemical formula | C24H36O4·0.5H2O |
Mr | 397.56 |
Crystal system, space group | Monoclinic, C2 |
Temperature (K) | 293 |
a, b, c (Å) | 13.144 (3), 7.750 (2), 22.415 (5) |
β (°) | 100.87 (1) |
V (Å3) | 2242.4 (9) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.65 × 0.60 × 0.10 |
Data collection | |
Diffractometer | Siemens P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4412, 2127, 1191 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.109, 1.02 |
No. of reflections | 2127 |
No. of parameters | 265 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.11, −0.13 |
Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXP97 (Sheldrick, 1997), SHELXL97.
O3—C24 | 1.230 (6) | O4—C24 | 1.246 (6) |
O3—C24—C23 | 120.7 (5) | O4—C24—C23 | 117.4 (5) |
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The carbonyl basicities of carboxylic acids and ketones are sufficiently similar that the two may compete as hydrogen-bond acceptors. Keto acids thus display several solid-state hydrogen-bonding modes not seen in functionally unelaborated acids. Our continuing study of the crystallography of keto acids explores the molecular characteristics that control their five known hydrogen-bonding modes. The commonest of these is acid dimerization without ketone involvement, but carboxyl-to-ketone catemers constitute a sizable minority of cases. The remaining types, intramolecular hydrogen-bonds, acid-to-acid catemers and carboxyl-to-ketone dimers, are all comparatively rare. In addition, about a dozen hydrates are known, having more complex hydrogen-bonding patterns (Lalancette et al., 1990, 1997, 1998). \sch
We have investigated the hydrogen-bonding motif of the diketo acid (I), and we describe here the structure of its hemihydrate. Compound (I), present as a single enantiomer, is the sixth in a series of steroidal keto acids we have examined. Fig. 1 shows the asymmetric unit with its steroid numbering. Because of the rigidity of the polycyclic structure, the major conformational options all lie in the branched chain attached at C17. Here, the substituents at C20 (which has the R configuration) are staggered with respect to those at C17, with the methyl (C21) anti to C16 (torsion angle C16—C17—C20—C21 is -177.0 (4)°). The remainder of this chain extends generally away from the ring system, as shown, with the carboxyl turned so that the O3—C24—C23—C22 torsion angle is -63.8 (7) °. At the remote end of the molecule the cis juncture between the two ketone rings (A and B) forces the A ring to lie at an angle to the plane of the remaining rings, creating a molecule with an angled L-shape. A partial water of hydration is found at an O···O distance of 2.891 (8) Å relative to the B-ring ketone (O2), but we were unable to find any electron density attributable to H atoms attached to this water, at least in part because its oxygen has an occupancy of only 50%. We have therefore chosen to model the presumed H bond to O2 using a water O—H distance of 0.80 Å, an H···O2 distance of 2.15 Å and an O—H···O angle of 153°. Because the position of this H was modeled on a presumed hydrogen bond rather than based on electron-density data, we have shown it as a `ghost' species in Fig. 1.
Distances to the species next nearest to the water O are so large that they are assumed to have little bearing on the position of the second water H [3.34 (2) Å to another (partial) water and 3.55 (1) Å to O1 in an adjacent molecule]. Thus, lacking a hydrogen-bonding partner, this H may well be disordered. Consequently we have no information on the position of the remaining unfound water H and have not attempted to show it in our asymmetric unit. There are, however, two intermolecular C—H···O close contacts to this water O (2.67 Å to H4B and 2.71 Å to H2A), which are close enough to exclude any water H from extending in those directions. These distances lie within the range we often employ (ca 2.7 Å) for non-bonded H···O packing interactions (Steiner, 1997). Using compiled data for a large number of C—H···O contacts, Steiner & Desiraju (1998) find significant statistical directionality even as far out as 3.0 Å, and conclude that these are legitimately viewed as `weak hydrogen bonds, with a greater contribution to packing forces than simple van der Waals attractions.
No disorder was detected in the three methyl groups, which all adopt staggered arrangements. However, as is frequently found in carboxyl dimers (Leiserowitz, 1976), complete averaging of carboxyl C—O bond lengths and C—C—O angles by disorder is observed here, with lengths of 1.230 (6) & 1.246 (6) Å for O3 & O4, respectively, and angles of 120.7 (5) & 117.4 (5)°, respectively. By contrast, values cited as typical for highly ordered dimeric carboxyls are 1.21 and 1.31 Å and 123 and 112° (Borthwick, 1980). Consistent with this disorder, the partial carboxyl H atoms were found at appropriate positions in electron-density difference maps, and refined with occupancies set at 50% each.
Fig. 2 illustrates the packing of (I) in the cell, with extracellular molecules included to show the hydrogen-bond pairing of carboxyl groups at crystallographic sites along the a and b edges of the chosen cell. The participating molecules are related by a C2 axis. The intermolecular O···O distance for the dimer is 2.643 (7) and 2.716 (7) Å for O4···O4' and O3···O3', respectively, and the O—H···O angles are both 165°. At sites 1/2, 1/2, 1/2; 1/2, 0, 1/2; 0, 0, 1/2 and 0, 1/2, 1/2 the bent ketone ends of the molecules approach each other in an arrangement which includes the partial waters of hydration H bonded to the B-ring ketone, as described above. Each water is hydrogen bonded only to its B-ring ketone and does not serve to bridge adjacent molecules. At this end of the molecule, the A-ring C═O groups overlap and stack with their dipoles opposed in an aligned alternating fashion that presumably maximizes attractive dipolar interactions (Lalancette et al., 1998). In addition to the intermolecular close C—H···O contacts involving the water O, described above, such close contacts were also found between O1 and H5A (2.67 Å) and between O2 and H1B (2.65 Å) in adjacent molecules.