Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101018601/fr1353sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101018601/fr1353Isup2.hkl |
CCDC reference: 180158
Compound (I), of known absolute stereochemistry and rotation, was purchased from Steraloids Inc., Newport, RI, USA, and recrystallized from 95% ethanol (m.p. 532 K).
All H atoms were found in electron-density difference maps but were placed in calculated positions and allowed to refine as riding models. C—H distances were 0.93–0.98 Å, and the O—H group was constrained to be 0.82 Å. A torsional parameter was refined for each methyl group.
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
C22H32O3 | Dx = 1.188 Mg m−3 |
Mr = 344.48 | Melting point: 532 K |
Orthorhombic, P21212 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.684 (3) Å | Cell parameters from 25 reflections |
b = 27.325 (7) Å | θ = 2.4–9.7° |
c = 7.281 (4) Å | µ = 0.08 mm−1 |
V = 1926.7 (13) Å3 | T = 296 K |
Z = 4 | Hexagonal rod, colourless |
F(000) = 752 | 0.31 × 0.15 × 0.10 mm |
Siemens P4 diffractometer | 1453 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.072 |
Graphite monochromator | θmax = 25.0°, θmin = 2.2° |
2θ/θ scans | h = −11→11 |
Absorption correction: numerical (Sheldrick, 1997) | k = −32→32 |
Tmin = 0.98, Tmax = 0.99 | l = −8→8 |
7753 measured reflections | 3 standard reflections every 97 reflections |
1990 independent reflections | intensity decay: Variation < 3% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.050 | H-atom parameters constrained |
wR(F2) = 0.114 | w = 1/[σ2(Fo2) + (0.0512P)2 + 0.1332P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.04 |
1990 reflections | Δρmax = 0.15 e Å−3 |
227 parameters | Δρmin = −0.13 e Å−3 |
0 restraints | Extinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0048 (13) |
C22H32O3 | V = 1926.7 (13) Å3 |
Mr = 344.48 | Z = 4 |
Orthorhombic, P21212 | Mo Kα radiation |
a = 9.684 (3) Å | µ = 0.08 mm−1 |
b = 27.325 (7) Å | T = 296 K |
c = 7.281 (4) Å | 0.31 × 0.15 × 0.10 mm |
Siemens P4 diffractometer | 1453 reflections with I > 2σ(I) |
Absorption correction: numerical (Sheldrick, 1997) | Rint = 0.072 |
Tmin = 0.98, Tmax = 0.99 | 3 standard reflections every 97 reflections |
7753 measured reflections | intensity decay: Variation < 3% |
1990 independent reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.114 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.15 e Å−3 |
1990 reflections | Δρmin = −0.13 e Å−3 |
227 parameters |
x | y | z | Uiso*/Ueq | ||
O1 | 0.1113 (3) | 0.45528 (9) | 0.8176 (4) | 0.0703 (9) | |
O2 | 0.2437 (3) | 0.89431 (12) | 0.5441 (6) | 0.1049 (14) | |
O3 | 0.4631 (3) | 0.90123 (10) | 0.4765 (5) | 0.0790 (10) | |
C1 | 0.2259 (4) | 0.57278 (12) | 0.9705 (5) | 0.0479 (10) | |
C2 | 0.2075 (5) | 0.51783 (13) | 1.0002 (5) | 0.0558 (11) | |
C3 | 0.1814 (4) | 0.49261 (12) | 0.8234 (6) | 0.0517 (10) | |
C4 | 0.2499 (4) | 0.51243 (13) | 0.6639 (5) | 0.0515 (10) | |
C5 | 0.3257 (4) | 0.55335 (12) | 0.6638 (5) | 0.0427 (9) | |
C6 | 0.4048 (5) | 0.56829 (13) | 0.4963 (5) | 0.0544 (11) | |
C7 | 0.3782 (4) | 0.62151 (13) | 0.4436 (5) | 0.0512 (10) | |
C8 | 0.4060 (4) | 0.65541 (11) | 0.6051 (4) | 0.0357 (8) | |
C9 | 0.3171 (4) | 0.64046 (11) | 0.7702 (4) | 0.0354 (8) | |
C10 | 0.3375 (4) | 0.58592 (11) | 0.8304 (5) | 0.0374 (8) | |
C11 | 0.3295 (4) | 0.67672 (11) | 0.9282 (4) | 0.0411 (9) | |
C12 | 0.3068 (4) | 0.72992 (11) | 0.8724 (4) | 0.0383 (9) | |
C13 | 0.4006 (3) | 0.74492 (12) | 0.7139 (4) | 0.0330 (8) | |
C14 | 0.3737 (3) | 0.70812 (12) | 0.5584 (4) | 0.0352 (8) | |
C15 | 0.4401 (4) | 0.73125 (13) | 0.3902 (5) | 0.0456 (10) | |
C16 | 0.4247 (4) | 0.78633 (13) | 0.4208 (5) | 0.0456 (10) | |
C17 | 0.3632 (4) | 0.79328 (12) | 0.6146 (5) | 0.0382 (8) | |
C18 | 0.5514 (4) | 0.74581 (13) | 0.7735 (5) | 0.0461 (9) | |
C19 | 0.4832 (4) | 0.57791 (13) | 0.9136 (6) | 0.0528 (10) | |
C20 | 0.4040 (4) | 0.84230 (12) | 0.6991 (5) | 0.0521 (10) | |
C21 | 0.3384 (6) | 0.85185 (16) | 0.8871 (6) | 0.0892 (17) | |
C22 | 0.3597 (5) | 0.88193 (14) | 0.5670 (7) | 0.0598 (11) | |
H3A | 0.4335 | 0.9171 | 0.3894 | 0.118* | |
H1A | 0.2489 | 0.5879 | 1.0871 | 0.057* | |
H1B | 0.1387 | 0.5865 | 0.9298 | 0.057* | |
H2A | 0.2900 | 0.5045 | 1.0567 | 0.067* | |
H2B | 0.1305 | 0.5122 | 1.0828 | 0.067* | |
H4A | 0.2406 | 0.4956 | 0.5536 | 0.062* | |
H6A | 0.3789 | 0.5473 | 0.3946 | 0.065* | |
H6B | 0.5027 | 0.5638 | 0.5188 | 0.065* | |
H7A | 0.4375 | 0.6305 | 0.3416 | 0.061* | |
H7B | 0.2830 | 0.6252 | 0.4042 | 0.061* | |
H8A | 0.5036 | 0.6529 | 0.6393 | 0.043* | |
H9A | 0.2212 | 0.6428 | 0.7281 | 0.042* | |
H11A | 0.4208 | 0.6737 | 0.9820 | 0.049* | |
H11B | 0.2626 | 0.6681 | 1.0220 | 0.049* | |
H12A | 0.2112 | 0.7344 | 0.8364 | 0.046* | |
H12B | 0.3246 | 0.7509 | 0.9771 | 0.046* | |
H14A | 0.2740 | 0.7092 | 0.5359 | 0.042* | |
H15A | 0.3930 | 0.7212 | 0.2789 | 0.055* | |
H15B | 0.5367 | 0.7222 | 0.3812 | 0.055* | |
H16A | 0.3639 | 0.8003 | 0.3290 | 0.055* | |
H16B | 0.5139 | 0.8023 | 0.4122 | 0.055* | |
H17A | 0.2625 | 0.7937 | 0.6006 | 0.046* | |
H18A | 0.5736 | 0.7157 | 0.8349 | 0.069* | |
H18B | 0.5663 | 0.7728 | 0.8557 | 0.069* | |
H18C | 0.6094 | 0.7495 | 0.6674 | 0.069* | |
H19A | 0.4932 | 0.5443 | 0.9494 | 0.079* | |
H19B | 0.4944 | 0.5985 | 1.0192 | 0.079* | |
H19C | 0.5521 | 0.5859 | 0.8237 | 0.079* | |
H20A | 0.5047 | 0.8434 | 0.7120 | 0.063* | |
H21A | 0.3681 | 0.8831 | 0.9322 | 0.134* | |
H21B | 0.3662 | 0.8267 | 0.9714 | 0.134* | |
H21C | 0.2396 | 0.8517 | 0.8754 | 0.134* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.088 (2) | 0.0385 (15) | 0.084 (2) | −0.0176 (15) | 0.014 (2) | −0.0114 (16) |
O2 | 0.064 (2) | 0.089 (2) | 0.162 (4) | 0.0206 (18) | 0.010 (3) | 0.065 (3) |
O3 | 0.071 (2) | 0.0652 (19) | 0.101 (3) | 0.0041 (16) | 0.008 (2) | 0.0381 (19) |
C1 | 0.065 (3) | 0.038 (2) | 0.041 (2) | −0.0078 (18) | 0.004 (2) | −0.0039 (17) |
C2 | 0.069 (3) | 0.044 (2) | 0.054 (2) | −0.006 (2) | 0.004 (2) | 0.001 (2) |
C3 | 0.058 (2) | 0.031 (2) | 0.066 (2) | −0.0019 (19) | 0.002 (2) | −0.005 (2) |
C4 | 0.069 (3) | 0.039 (2) | 0.046 (2) | −0.007 (2) | 0.000 (2) | −0.0124 (18) |
C5 | 0.050 (2) | 0.038 (2) | 0.039 (2) | 0.0047 (18) | −0.0006 (19) | −0.0045 (17) |
C6 | 0.074 (3) | 0.042 (2) | 0.048 (2) | 0.001 (2) | 0.013 (2) | −0.0139 (19) |
C7 | 0.074 (3) | 0.047 (2) | 0.032 (2) | −0.005 (2) | 0.012 (2) | −0.0037 (18) |
C8 | 0.0389 (19) | 0.0381 (18) | 0.0302 (17) | −0.0016 (16) | 0.0023 (17) | −0.0036 (16) |
C9 | 0.0379 (19) | 0.0347 (18) | 0.0336 (17) | −0.0021 (15) | −0.0048 (17) | 0.0001 (15) |
C10 | 0.042 (2) | 0.0328 (18) | 0.0379 (18) | −0.0012 (16) | −0.0012 (18) | −0.0039 (16) |
C11 | 0.053 (2) | 0.0388 (19) | 0.0312 (19) | −0.0030 (17) | 0.000 (2) | −0.0012 (16) |
C12 | 0.050 (2) | 0.0351 (18) | 0.0299 (18) | −0.0010 (16) | 0.0017 (18) | −0.0016 (15) |
C13 | 0.0323 (18) | 0.0323 (17) | 0.0345 (18) | 0.0010 (15) | −0.0026 (16) | 0.0006 (16) |
C14 | 0.0330 (18) | 0.0420 (19) | 0.0307 (17) | −0.0001 (16) | 0.0000 (17) | 0.0006 (16) |
C15 | 0.052 (2) | 0.049 (2) | 0.036 (2) | −0.0022 (17) | 0.007 (2) | 0.0057 (18) |
C16 | 0.044 (2) | 0.047 (2) | 0.046 (2) | −0.0012 (17) | 0.001 (2) | 0.0096 (19) |
C17 | 0.0326 (18) | 0.0416 (19) | 0.0405 (19) | −0.0002 (16) | −0.0036 (18) | 0.0057 (17) |
C18 | 0.047 (2) | 0.046 (2) | 0.045 (2) | 0.0001 (18) | −0.0094 (19) | 0.0028 (18) |
C19 | 0.064 (3) | 0.038 (2) | 0.057 (2) | 0.0086 (18) | −0.006 (2) | 0.000 (2) |
C20 | 0.060 (3) | 0.040 (2) | 0.057 (2) | −0.0024 (19) | −0.002 (2) | 0.009 (2) |
C21 | 0.150 (5) | 0.049 (3) | 0.069 (3) | −0.002 (3) | 0.019 (4) | −0.012 (2) |
C22 | 0.061 (3) | 0.037 (2) | 0.082 (3) | 0.000 (2) | 0.004 (3) | 0.005 (2) |
O1—C3 | 1.226 (4) | C1—H1B | 0.9700 |
O2—C22 | 1.185 (5) | C2—H2A | 0.9700 |
O3—C22 | 1.310 (5) | C2—H2B | 0.9700 |
C1—C2 | 1.528 (5) | C4—H4A | 0.9300 |
C1—C10 | 1.529 (5) | C6—H6A | 0.9700 |
C2—C3 | 1.482 (5) | C6—H6B | 0.9700 |
C3—C4 | 1.443 (5) | C7—H7A | 0.9700 |
C4—C5 | 1.338 (5) | C7—H7B | 0.9700 |
C5—C6 | 1.497 (5) | C8—H8A | 0.9800 |
C5—C10 | 1.509 (5) | C9—H9A | 0.9800 |
C6—C7 | 1.526 (5) | C11—H11A | 0.9700 |
C7—C8 | 1.521 (5) | C11—H11B | 0.9700 |
C8—C14 | 1.513 (4) | C12—H12A | 0.9700 |
C8—C9 | 1.534 (4) | C12—H12B | 0.9700 |
C9—C11 | 1.523 (4) | C14—H14A | 0.9800 |
C9—C10 | 1.566 (4) | C15—H15A | 0.9700 |
C10—C19 | 1.550 (5) | C15—H15B | 0.9700 |
C11—C12 | 1.525 (4) | C16—H16A | 0.9700 |
C12—C13 | 1.525 (5) | C16—H16B | 0.9700 |
C13—C18 | 1.524 (5) | C17—H17A | 0.9800 |
C13—C14 | 1.537 (4) | C18—H18A | 0.9600 |
C13—C17 | 1.549 (4) | C18—H18B | 0.9600 |
C14—C15 | 1.521 (5) | C18—H18C | 0.9600 |
C15—C16 | 1.529 (5) | C19—H19A | 0.9600 |
C16—C17 | 1.543 (5) | C19—H19B | 0.9600 |
C17—C20 | 1.526 (5) | C19—H19C | 0.9600 |
C20—C22 | 1.511 (6) | C20—H20A | 0.9800 |
C20—C21 | 1.531 (6) | C21—H21A | 0.9600 |
O3—H3A | 0.8200 | C21—H21B | 0.9600 |
C1—H1A | 0.9700 | C21—H21C | 0.9600 |
C2—C1—C10 | 114.1 (3) | C7—C6—H6B | 109.2 |
C3—C2—C1 | 110.7 (3) | H6A—C6—H6B | 107.9 |
O1—C3—C4 | 122.6 (4) | C8—C7—H7A | 109.5 |
O1—C3—C2 | 120.7 (4) | C6—C7—H7A | 109.5 |
C4—C3—C2 | 116.5 (3) | C8—C7—H7B | 109.5 |
C5—C4—C3 | 124.5 (3) | C6—C7—H7B | 109.5 |
C4—C5—C6 | 120.6 (3) | H7A—C7—H7B | 108.1 |
C4—C5—C10 | 122.3 (3) | C14—C8—H8A | 108.9 |
C6—C5—C10 | 117.1 (3) | C7—C8—H8A | 108.9 |
C5—C6—C7 | 112.3 (3) | C9—C8—H8A | 108.9 |
C8—C7—C6 | 110.8 (3) | C11—C9—H9A | 105.6 |
C14—C8—C7 | 111.7 (3) | C8—C9—H9A | 105.6 |
C14—C8—C9 | 108.3 (3) | C10—C9—H9A | 105.6 |
C7—C8—C9 | 110.1 (3) | C9—C11—H11A | 108.7 |
C11—C9—C8 | 112.0 (3) | C12—C11—H11A | 108.7 |
C11—C9—C10 | 113.5 (3) | C9—C11—H11B | 108.7 |
C8—C9—C10 | 113.7 (3) | C12—C11—H11B | 108.7 |
C5—C10—C1 | 110.1 (3) | H11A—C11—H11B | 107.6 |
C5—C10—C19 | 107.5 (3) | C13—C12—H12A | 109.3 |
C1—C10—C19 | 110.5 (3) | C11—C12—H12A | 109.3 |
C5—C10—C9 | 109.1 (3) | C13—C12—H12B | 109.3 |
C1—C10—C9 | 108.7 (3) | C11—C12—H12B | 109.3 |
C19—C10—C9 | 111.0 (3) | H12A—C12—H12B | 107.9 |
C9—C11—C12 | 114.1 (3) | C8—C14—H14A | 105.7 |
C13—C12—C11 | 111.8 (3) | C15—C14—H14A | 105.7 |
C18—C13—C12 | 111.1 (3) | C13—C14—H14A | 105.7 |
C18—C13—C14 | 112.5 (3) | C14—C15—H15A | 110.9 |
C12—C13—C14 | 106.3 (2) | C16—C15—H15A | 110.9 |
C18—C13—C17 | 110.1 (3) | C14—C15—H15B | 110.8 |
C12—C13—C17 | 116.3 (3) | C16—C15—H15B | 110.9 |
C14—C13—C17 | 100.1 (3) | H15A—C15—H15B | 108.9 |
C8—C14—C15 | 119.3 (3) | C15—C16—H16A | 110.3 |
C8—C14—C13 | 115.0 (3) | C17—C16—H16A | 110.3 |
C15—C14—C13 | 104.5 (3) | C15—C16—H16B | 110.3 |
C14—C15—C16 | 104.5 (3) | C17—C16—H16B | 110.3 |
C15—C16—C17 | 107.0 (3) | H16A—C16—H16B | 108.6 |
C20—C17—C16 | 112.1 (3) | C20—C17—H17A | 106.9 |
C20—C17—C13 | 120.0 (3) | C16—C17—H17A | 106.9 |
C16—C17—C13 | 103.4 (3) | C13—C17—H17A | 106.9 |
C22—C20—C17 | 107.4 (3) | C13—C18—H18A | 109.5 |
C22—C20—C21 | 109.2 (3) | C13—C18—H18B | 109.5 |
C17—C20—C21 | 113.7 (3) | H18A—C18—H18B | 109.5 |
O2—C22—O3 | 122.7 (4) | C13—C18—H18C | 109.5 |
O2—C22—C20 | 124.3 (4) | H18A—C18—H18C | 109.5 |
O3—C22—C20 | 113.0 (4) | H18B—C18—H18C | 109.5 |
C22—O3—H3A | 109.5 | C10—C19—H19A | 109.5 |
C2—C1—H1A | 108.7 | C10—C19—H19B | 109.5 |
C10—C1—H1A | 108.7 | H19A—C19—H19B | 109.5 |
C2—C1—H1B | 108.7 | C10—C19—H19C | 109.5 |
C10—C1—H1B | 108.7 | H19A—C19—H19C | 109.5 |
H1A—C1—H1B | 107.6 | H19B—C19—H19C | 109.5 |
C3—C2—H2A | 109.5 | C22—C20—H20A | 108.8 |
C1—C2—H2A | 109.5 | C17—C20—H20A | 108.8 |
C3—C2—H2B | 109.5 | C21—C20—H20A | 108.8 |
C1—C2—H2B | 109.5 | C20—C21—H21A | 109.5 |
H2A—C2—H2B | 108.1 | C20—C21—H21B | 109.5 |
C5—C4—H4A | 117.7 | H21A—C21—H21B | 109.5 |
C3—C4—H4A | 117.7 | C20—C21—H21C | 109.5 |
C5—C6—H6A | 109.2 | H21A—C21—H21C | 109.5 |
C7—C6—H6A | 109.2 | H21B—C21—H21C | 109.5 |
C5—C6—H6B | 109.2 | ||
C10—C1—C2—C3 | −54.7 (5) | C9—C11—C12—C13 | −53.8 (4) |
C1—C2—C3—O1 | −150.0 (4) | C11—C12—C13—C18 | −67.4 (4) |
C1—C2—C3—C4 | 33.9 (5) | C11—C12—C13—C14 | 55.3 (4) |
O1—C3—C4—C5 | 179.0 (4) | C11—C12—C13—C17 | 165.6 (3) |
C2—C3—C4—C5 | −5.0 (6) | C7—C8—C14—C15 | −54.1 (4) |
C3—C4—C5—C6 | 173.6 (4) | C9—C8—C14—C15 | −175.5 (3) |
C3—C4—C5—C10 | −5.4 (6) | C7—C8—C14—C13 | −179.4 (3) |
C4—C5—C6—C7 | 129.9 (4) | C9—C8—C14—C13 | 59.2 (3) |
C10—C5—C6—C7 | −51.0 (5) | C18—C13—C14—C8 | 60.8 (4) |
C5—C6—C7—C8 | 54.1 (5) | C12—C13—C14—C8 | −61.0 (4) |
C6—C7—C8—C14 | −177.3 (3) | C17—C13—C14—C8 | 177.6 (3) |
C6—C7—C8—C9 | −56.9 (4) | C18—C13—C14—C15 | −71.9 (4) |
C14—C8—C9—C11 | −51.3 (4) | C12—C13—C14—C15 | 166.3 (3) |
C7—C8—C9—C11 | −173.7 (3) | C17—C13—C14—C15 | 44.9 (3) |
C14—C8—C9—C10 | 178.5 (3) | C8—C14—C15—C16 | −161.9 (3) |
C7—C8—C9—C10 | 56.1 (4) | C13—C14—C15—C16 | −31.7 (4) |
C4—C5—C10—C1 | −14.5 (5) | C14—C15—C16—C17 | 5.6 (4) |
C6—C5—C10—C1 | 166.4 (3) | C15—C16—C17—C20 | 152.7 (3) |
C4—C5—C10—C19 | 105.9 (4) | C15—C16—C17—C13 | 22.1 (4) |
C6—C5—C10—C19 | −73.2 (4) | C18—C13—C17—C20 | −47.6 (4) |
C4—C5—C10—C9 | −133.7 (4) | C12—C13—C17—C20 | 79.9 (4) |
C6—C5—C10—C9 | 47.2 (4) | C14—C13—C17—C20 | −166.2 (3) |
C2—C1—C10—C5 | 44.2 (4) | C18—C13—C17—C16 | 78.2 (3) |
C2—C1—C10—C19 | −74.4 (4) | C12—C13—C17—C16 | −154.4 (3) |
C2—C1—C10—C9 | 163.6 (3) | C14—C13—C17—C16 | −40.4 (3) |
C11—C9—C10—C5 | −179.0 (3) | C16—C17—C20—C22 | 55.8 (4) |
C8—C9—C10—C5 | −49.6 (4) | C13—C17—C20—C22 | 177.4 (3) |
C11—C9—C10—C1 | 60.9 (4) | C16—C17—C20—C21 | 176.8 (3) |
C8—C9—C10—C1 | −169.6 (3) | C13—C17—C20—C21 | −61.7 (5) |
C11—C9—C10—C19 | −60.8 (4) | C17—C20—C22—O2 | 73.8 (6) |
C8—C9—C10—C19 | 68.7 (4) | C21—C20—C22—O2 | −49.9 (6) |
C8—C9—C11—C12 | 50.9 (4) | C17—C20—C22—O3 | −105.3 (4) |
C10—C9—C11—C12 | −178.8 (3) | C21—C20—C22—O3 | 130.9 (4) |
Experimental details
Crystal data | |
Chemical formula | C22H32O3 |
Mr | 344.48 |
Crystal system, space group | Orthorhombic, P21212 |
Temperature (K) | 296 |
a, b, c (Å) | 9.684 (3), 27.325 (7), 7.281 (4) |
V (Å3) | 1926.7 (13) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.31 × 0.15 × 0.10 |
Data collection | |
Diffractometer | Siemens P4 diffractometer |
Absorption correction | Numerical (Sheldrick, 1997) |
Tmin, Tmax | 0.98, 0.99 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7753, 1990, 1453 |
Rint | 0.072 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.114, 1.06 |
No. of reflections | 1990 |
No. of parameters | 227 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.15, −0.13 |
Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL (Sheldrick, 1997), SHELXTL.
O2—C22 | 1.185 (5) | O3—C22 | 1.310 (5) |
O2—C22—C20 | 124.3 (4) | O3—C22—C20 | 113.0 (4) |
C16—C17—C20—C21 | 176.8 (3) | C17—C20—C22—O2 | 73.8 (6) |
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Our interest in the crystal structures of keto carboxylic acids concerns the molecular characteristics that control their five known hydrogen-bonding patterns. The acid dimers that characterize functionally unelaborated acids also predominate generally in keto acids. However, in non-racemates with significant conformational restrictions, the prevalence of acid-to-ketone catemers rises dramatically (Brunskill et al., 1999). Consequently, we have sought subject materials with terpenoid origins, and now report the crystal structure and hydrogen-bonding behavior of (I), the seventh in our series of steroidal keto acids.
Fig. 1 shows the asymmetric unit of (I) with its steroid numbering. Among the few conformational options present, the substituents at C20, which has the S configuration, are staggered with respect to those at C17, so that the C16—C17—C20—C21 torsion angle is 176.8 (3)°. The carboxyl plane coincides approximately with the C20—H20 bond, but the carboxyl group is turned with its carbonyl toward the bottom (α) face of the molecule [torsion angle C17—C20—C22—O2 = 73.8 (6)°]. In both of the steroids we have previously examined having this 23,24-dinor-22-oic acid side chain, the hydrogen-bonding patterns are very different from that in (I), and in both, the carboxyl carbonyl is oriented β (Lalancette et al., 1998; Thompson et al., 1999).
Complete or partial averaging of carboxyl C—O bond lengths and C—C—O angles by disorder is frequent in hydrogen-bonding dimers (Leiserowitz, 1976). However, catemers, hydrates and other hydrogen-bonding structures whose geometry precludes the usual carboxyl-disordering processes are highly ordered, as is found here. Our own survey of 56 keto acid structures which are not acid dimers gives average values of 1.20 (1) and 1.32 (2) Å, and 124.5 (14) and 112.7 (17)° for these lengths and angles, respectively, in accord with typical values of 1.21/1.31 Å and 123/112°, respectively, cited for highly ordered dimeric carboxyls (Borthwick, 1980). In (I), these lengths and angles are 1.185 (5)/1.311 (5) Å and 124.3 (4)/113.1 (4)°, respectively. No disorder was detected in the three methyl groups (C18, C19 and C21), which all adopt staggered arrangements.
Fig. 2 shows the packing of the cell and illustrates the two parallel hydrogen-bonding catemers created by the acid-to-ketone hydrogen bonding among molecules screw-related in b [O···O = 2.699 (4) Å and O—H···O = 173°]. The two chains are screw-related in a, and lie with their long axes parallel, but with opposite end-to-end orientation. In spite of a relatively slight change in molecular shape, this is dramatically different from the case of the 5-α-dihydro analog, whose hydrogen bonding is of the acid-to-acid type (Lalancette et al., 1998).
Within each molecule of (I), the dihedral angle between the carboxyl (C20/C22/O2/O3) and ketone planes (C2/C3/C4/O1) is 79.3 (2)°. However, for each hydrogen bond, the intermolecular dihedral angle between these two planes is 64.4 (3)°. We characterize the geometry of hydrogen bonding to carbonyls using a combination of the H···O═C angle and the H···O═C—C torsion angle. These describe the approach of the H atom to the O atom in terms of its deviation from, respectively, C═O axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I), these angles are 128 and -3°, respectively.
Intermolecular C—H···O═C close contacts to different neighboring molecules were found, involving O1 (2.69 Å to H21A) and O2 (2.64 Å to H6B). These distances lie within the 2.7 Å range we often employ for non-bonded C—H···O packing interactions (Steiner, 1997). Using compiled data for a large number of such 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.
We categorize subtypes of catemers by describing the relationship of adjacent molecules in the chains as homochiral (screw, translation) and heterochiral (glide). Among hydrogen-bonding catemers overall, the observed prevalence within the former grouping, appropriate to (I), is screw > translation, however this is our first observation of a screw-related steroidal catemer. Among the six previous steroid keto acids whose X-ray structures we have reported, all three of the cases displaying catemeric hydrogen bonding were translational.
The KBr IR spectrum of (I) displays C═O absorptions at 1723 (COOH) and 1649 cm-1 (ketone), consistent with known shifts produced when hydrogen bonding is removed from carboxyl C═O and added to a ketone, plus an alkene absorption at 1614 cm-1. In CHCl3 solution, where dimers predominate, these peaks appear, normally, at 1707 and 1660 cm-1, with the C═C peak at 1614 cm-1 and a large carboxyl-dilution shoulder at ca 1732 cm-1.