Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103018997/fr1424sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103018997/fr1424Isup2.hkl |
CCDC reference: 224666
Commercial (-)-α-santonin of known relative and absolute stereochemistry (Barton et al., 1962; Nakazaki & Arakawa, 1962; Asher & Sim, 1965; Coggin & Sim, 1969) was obtained from Aldrich Chemical Co., Milwaukee, Wisconsin, USA, and subjected to Li—NH3 reduction (Bruderer et al., 1956; Howe et al., 1959). The resulting α,β-unsaturated ketone was then hydrogenated over Pd/C catalyst and chromatographed on alumina, to provide (I). Crystals of (I) (m.p. 384 K) suitable for X-ray diffraction analysis were obtained from ether-hexane (Ratio?). The stereochemistry found agrees with that previously assigned to the isomer (of negative optical rotation) having this m.p. (Miki, 1955; Abe et al., 1956; Djerassi et al., 1958; Ando et al., 1980).
Friedel-related data were averaged. All H atoms were found in electron-density difference maps. C-bound H atoms were placed in calculated positions (C—H = 0.97 Å for methylene H, 0.98 Å for methane H and 0.96 Å for methyl H) and allowed to refine as riding models on their respective C atoms; their displacement parameters were fixed at 120% of those of their respective C atoms, except for the methyl H, which were fixed at 150% of their respective C atoms. Hydroxyl H atoms were fixed at O—H = 0.82 Å and their displacement parameters were fixed at 120% of those of their respective O atoms.
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 in SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 in SHELXTL (Sheldrick, 1997); molecular graphics: SHELXP97 in SHELXTL (Sheldrick, 1997); software used to prepare material for publication: SHELXL97 in SHELXTL.
C15H24O3 | F(000) = 552 |
Mr = 252.34 | Dx = 1.167 Mg m−3 |
Monoclinic, P21 | Melting point: 384 K |
Hall symbol: P 2yb | Mo Kα radiation, λ = 0.71073 Å |
a = 10.136 (3) Å | Cell parameters from 28 reflections |
b = 14.867 (4) Å | θ = 2.1–10.5° |
c = 10.238 (3) Å | µ = 0.08 mm−1 |
β = 111.36 (2)° | T = 296 K |
V = 1436.8 (7) Å3 | Parellelepiped, colorless |
Z = 4 | 0.25 × 0.22 × 0.07 mm |
Siemens P4 diffractometer | 1462 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.060 |
Graphite monochromator | θmax = 25.0°, θmin = 2.1° |
2θ/θ scans | h = −11→11 |
Absorption correction: numerical (SHELXTL; Sheldrick, 1997) | k = −17→17 |
Tmin = 0.96, Tmax = 0.99 | l = −12→12 |
5322 measured reflections | 3 standard reflections every 97 reflections |
2590 independent reflections | intensity decay: variation < 4.0% |
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)] = 0.055 | H-atom parameters constrained |
wR(F2) = 0.120 | w = 1/[σ2(Fo2) + (0.0354P)2 + 0.1319P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
2590 reflections | Δρmax = 0.14 e Å−3 |
328 parameters | Δρmin = −0.13 e Å−3 |
1 restraint | Extinction correction: SHELXL97 in SHELXTL (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0114 (17) |
C15H24O3 | V = 1436.8 (7) Å3 |
Mr = 252.34 | Z = 4 |
Monoclinic, P21 | Mo Kα radiation |
a = 10.136 (3) Å | µ = 0.08 mm−1 |
b = 14.867 (4) Å | T = 296 K |
c = 10.238 (3) Å | 0.25 × 0.22 × 0.07 mm |
β = 111.36 (2)° |
Siemens P4 diffractometer | 1462 reflections with I > 2σ(I) |
Absorption correction: numerical (SHELXTL; Sheldrick, 1997) | Rint = 0.060 |
Tmin = 0.96, Tmax = 0.99 | 3 standard reflections every 97 reflections |
5322 measured reflections | intensity decay: variation < 4.0% |
2590 independent reflections |
R[F2 > 2σ(F2)] = 0.055 | 1 restraint |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.14 e Å−3 |
2590 reflections | Δρmin = −0.13 e Å−3 |
328 parameters |
Experimental. crystal mounted on glass fiber using cyanoacrylate |
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 | ||
O1 | 0.5697 (5) | 0.8479 (3) | 0.3222 (4) | 0.0745 (13) | |
O2 | 0.2176 (5) | 0.5362 (4) | 0.6808 (4) | 0.0920 (15) | |
O3 | 0.4256 (5) | 0.4981 (3) | 0.8366 (4) | 0.0817 (14) | |
H3 | 0.4159 | 0.4553 | 0.7834 | 0.098* | |
O1' | 0.9341 (5) | 0.6871 (3) | 0.6663 (5) | 0.0927 (16) | |
O2' | 1.2356 (6) | 0.9877 (3) | 0.2824 (5) | 0.0919 (15) | |
O3' | 1.0268 (6) | 1.0473 (3) | 0.1529 (4) | 0.0897 (15) | |
H3' | 1.0501 | 1.0865 | 0.2134 | 0.108* | |
C1 | 0.4137 (6) | 0.7126 (4) | 0.6758 (5) | 0.0509 (14) | |
H1A | 0.4139 | 0.6547 | 0.6322 | 0.061* | |
H1B | 0.3182 | 0.7364 | 0.6371 | 0.061* | |
C2 | 0.4542 (6) | 0.6987 (4) | 0.8343 (5) | 0.0480 (14) | |
H2A | 0.5436 | 0.6653 | 0.8689 | 0.058* | |
C3 | 0.4784 (6) | 0.7887 (4) | 0.9112 (5) | 0.0590 (16) | |
H3A | 0.3878 | 0.8183 | 0.8912 | 0.071* | |
H3B | 0.5194 | 0.7780 | 1.0114 | 0.071* | |
C4 | 0.5758 (6) | 0.8506 (4) | 0.8689 (5) | 0.0581 (15) | |
H4A | 0.6695 | 0.8240 | 0.8992 | 0.070* | |
H4B | 0.5837 | 0.9076 | 0.9174 | 0.070* | |
C4a | 0.5242 (5) | 0.8683 (4) | 0.7101 (5) | 0.0487 (14) | |
C5 | 0.6355 (7) | 0.9242 (4) | 0.6765 (6) | 0.0687 (17) | |
H5A | 0.6464 | 0.9821 | 0.7231 | 0.082* | |
H5B | 0.7261 | 0.8935 | 0.7126 | 0.082* | |
C6 | 0.5934 (6) | 0.9389 (4) | 0.5186 (6) | 0.0648 (17) | |
H6A | 0.5165 | 0.9822 | 0.4880 | 0.078* | |
H6B | 0.6733 | 0.9650 | 0.5015 | 0.078* | |
C7 | 0.5479 (6) | 0.8562 (4) | 0.4312 (6) | 0.0569 (16) | |
C8 | 0.4697 (6) | 0.7840 (4) | 0.4773 (5) | 0.0554 (15) | |
H8A | 0.3700 | 0.8023 | 0.4416 | 0.066* | |
C8a | 0.5135 (6) | 0.7766 (3) | 0.6386 (5) | 0.0442 (13) | |
H8B | 0.6081 | 0.7496 | 0.6749 | 0.053* | |
C9 | 0.3401 (6) | 0.6408 (4) | 0.8623 (5) | 0.0520 (14) | |
H9A | 0.2509 | 0.6744 | 0.8263 | 0.062* | |
C10 | 0.3177 (8) | 0.5546 (5) | 0.7828 (6) | 0.0628 (17) | |
C11 | 0.3728 (7) | 0.6235 (5) | 1.0192 (5) | 0.0729 (19) | |
H11A | 0.2976 | 0.5888 | 1.0302 | 0.109* | |
H11B | 0.3808 | 0.6799 | 1.0672 | 0.109* | |
H11C | 0.4603 | 0.5910 | 1.0583 | 0.109* | |
C12 | 0.4743 (8) | 0.6940 (4) | 0.4078 (6) | 0.085 (2) | |
H12A | 0.4469 | 0.7025 | 0.3085 | 0.128* | |
H12B | 0.4101 | 0.6527 | 0.4259 | 0.128* | |
H12C | 0.5687 | 0.6701 | 0.4453 | 0.128* | |
C13 | 0.3856 (7) | 0.9206 (4) | 0.6645 (6) | 0.0730 (19) | |
H13A | 0.3539 | 0.9324 | 0.5656 | 0.110* | |
H13B | 0.4002 | 0.9766 | 0.7146 | 0.110* | |
H13C | 0.3153 | 0.8859 | 0.6845 | 0.110* | |
C1' | 0.9893 (6) | 0.8311 (4) | 0.2643 (5) | 0.0582 (16) | |
H1'A | 0.8921 | 0.8434 | 0.2042 | 0.070* | |
H1'B | 1.0242 | 0.8828 | 0.3248 | 0.070* | |
C2' | 1.0782 (6) | 0.8184 (4) | 0.1740 (5) | 0.0510 (14) | |
H2'A | 1.1760 | 0.8089 | 0.2381 | 0.061* | |
C3' | 1.0329 (7) | 0.7334 (4) | 0.0856 (5) | 0.0653 (18) | |
H3'A | 1.0961 | 0.7234 | 0.0351 | 0.078* | |
H3'B | 0.9380 | 0.7416 | 0.0171 | 0.078* | |
C4' | 1.0353 (7) | 0.6510 (4) | 0.1756 (6) | 0.0631 (17) | |
H4'A | 1.1322 | 0.6392 | 0.2367 | 0.076* | |
H4'B | 1.0017 | 0.5993 | 0.1149 | 0.076* | |
C4'a | 0.9439 (5) | 0.6624 (3) | 0.2655 (5) | 0.0511 (15) | |
C5' | 0.9700 (7) | 0.5824 (4) | 0.3668 (6) | 0.0662 (17) | |
H5'A | 0.9377 | 0.5279 | 0.3127 | 0.079* | |
H5'B | 1.0711 | 0.5766 | 0.4179 | 0.079* | |
C6' | 0.8967 (6) | 0.5907 (4) | 0.4710 (6) | 0.0631 (17) | |
H6'A | 0.7960 | 0.5806 | 0.4224 | 0.076* | |
H6'B | 0.9319 | 0.5439 | 0.5412 | 0.076* | |
C7' | 0.9172 (6) | 0.6805 (4) | 0.5440 (6) | 0.0574 (15) | |
C8' | 0.9142 (6) | 0.7626 (4) | 0.4565 (5) | 0.0527 (15) | |
H8'A | 0.8145 | 0.7721 | 0.3976 | 0.063* | |
C8'a | 0.9927 (6) | 0.7485 (3) | 0.3545 (5) | 0.0439 (13) | |
H8'B | 1.0925 | 0.7389 | 0.4130 | 0.053* | |
C9' | 1.0785 (7) | 0.9030 (4) | 0.0872 (6) | 0.0644 (17) | |
H9'A | 0.9820 | 0.9135 | 0.0207 | 0.077* | |
C10' | 1.1249 (9) | 0.9843 (4) | 0.1850 (7) | 0.0657 (18) | |
C11' | 1.1777 (8) | 0.8949 (5) | 0.0049 (7) | 0.095 (2) | |
H11D | 1.1484 | 0.8452 | −0.0590 | 0.142* | |
H11E | 1.2729 | 0.8852 | 0.0690 | 0.142* | |
H11F | 1.1738 | 0.9494 | −0.0468 | 0.142* | |
C12' | 0.9608 (7) | 0.8475 (4) | 0.5472 (6) | 0.0712 (18) | |
H12D | 0.9077 | 0.8526 | 0.6076 | 0.107* | |
H12E | 0.9439 | 0.8995 | 0.4877 | 0.107* | |
H12F | 1.0599 | 0.8435 | 0.6029 | 0.107* | |
C13' | 0.7872 (6) | 0.6653 (4) | 0.1711 (6) | 0.0761 (18) | |
H13D | 0.7703 | 0.7161 | 0.1092 | 0.114* | |
H13E | 0.7303 | 0.6706 | 0.2279 | 0.114* | |
H13F | 0.7625 | 0.6110 | 0.1168 | 0.114* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.110 (4) | 0.069 (3) | 0.062 (3) | 0.001 (3) | 0.052 (3) | 0.008 (2) |
O2 | 0.086 (3) | 0.115 (4) | 0.065 (3) | −0.014 (3) | 0.016 (3) | −0.024 (3) |
O3 | 0.116 (4) | 0.067 (3) | 0.057 (3) | 0.014 (3) | 0.026 (3) | −0.006 (2) |
O1' | 0.166 (5) | 0.062 (3) | 0.063 (3) | −0.007 (3) | 0.056 (3) | 0.002 (3) |
O2' | 0.093 (4) | 0.088 (4) | 0.091 (3) | −0.002 (3) | 0.028 (3) | −0.013 (3) |
O3' | 0.143 (5) | 0.057 (3) | 0.066 (3) | 0.030 (3) | 0.035 (3) | 0.002 (2) |
C1 | 0.064 (4) | 0.053 (3) | 0.037 (3) | 0.002 (3) | 0.020 (3) | −0.003 (3) |
C2 | 0.056 (4) | 0.054 (3) | 0.032 (3) | 0.008 (3) | 0.014 (3) | −0.001 (3) |
C3 | 0.069 (4) | 0.064 (4) | 0.039 (3) | 0.010 (3) | 0.014 (3) | 0.000 (3) |
C4 | 0.071 (4) | 0.055 (4) | 0.042 (3) | 0.002 (3) | 0.013 (3) | −0.012 (3) |
C4a | 0.054 (4) | 0.047 (3) | 0.042 (3) | 0.008 (3) | 0.014 (3) | 0.001 (3) |
C5 | 0.087 (5) | 0.063 (4) | 0.055 (4) | −0.007 (4) | 0.025 (4) | −0.002 (3) |
C6 | 0.078 (4) | 0.063 (4) | 0.064 (4) | −0.005 (3) | 0.037 (3) | 0.002 (3) |
C7 | 0.068 (4) | 0.056 (4) | 0.049 (4) | 0.009 (3) | 0.024 (3) | 0.008 (3) |
C8 | 0.065 (4) | 0.062 (4) | 0.037 (3) | 0.000 (3) | 0.016 (3) | 0.001 (3) |
C8a | 0.046 (3) | 0.049 (3) | 0.041 (3) | 0.006 (3) | 0.020 (3) | −0.001 (3) |
C9 | 0.064 (4) | 0.063 (4) | 0.032 (3) | 0.009 (3) | 0.020 (3) | 0.002 (3) |
C10 | 0.078 (5) | 0.069 (5) | 0.044 (4) | 0.007 (4) | 0.026 (4) | 0.011 (4) |
C11 | 0.105 (5) | 0.075 (5) | 0.047 (3) | 0.002 (4) | 0.036 (3) | 0.005 (3) |
C12 | 0.141 (6) | 0.074 (5) | 0.059 (4) | −0.017 (5) | 0.058 (4) | −0.013 (4) |
C13 | 0.092 (5) | 0.057 (4) | 0.075 (4) | 0.032 (4) | 0.036 (4) | 0.015 (3) |
C1' | 0.072 (4) | 0.055 (4) | 0.048 (3) | 0.012 (3) | 0.022 (3) | 0.001 (3) |
C2' | 0.058 (4) | 0.051 (3) | 0.043 (3) | 0.008 (3) | 0.017 (3) | 0.001 (3) |
C3' | 0.094 (5) | 0.057 (4) | 0.046 (3) | 0.008 (4) | 0.027 (3) | −0.008 (3) |
C4' | 0.092 (5) | 0.045 (4) | 0.051 (3) | 0.015 (3) | 0.025 (3) | −0.007 (3) |
C4'a | 0.053 (3) | 0.042 (4) | 0.050 (3) | 0.004 (3) | 0.008 (3) | −0.003 (3) |
C5' | 0.091 (5) | 0.041 (4) | 0.058 (4) | −0.004 (3) | 0.017 (4) | −0.006 (3) |
C6' | 0.071 (4) | 0.050 (4) | 0.063 (4) | −0.014 (3) | 0.018 (3) | −0.003 (3) |
C7' | 0.069 (4) | 0.045 (4) | 0.058 (4) | −0.005 (3) | 0.022 (3) | −0.001 (3) |
C8' | 0.062 (4) | 0.043 (3) | 0.052 (3) | 0.001 (3) | 0.021 (3) | −0.001 (3) |
C8'a | 0.047 (3) | 0.044 (3) | 0.040 (3) | −0.001 (3) | 0.015 (3) | 0.003 (3) |
C9' | 0.086 (5) | 0.060 (4) | 0.052 (4) | 0.014 (4) | 0.032 (3) | 0.006 (3) |
C10' | 0.103 (6) | 0.057 (4) | 0.049 (4) | 0.006 (4) | 0.042 (4) | 0.010 (4) |
C11' | 0.157 (7) | 0.070 (5) | 0.087 (5) | 0.008 (5) | 0.080 (5) | 0.005 (4) |
C12' | 0.107 (5) | 0.054 (4) | 0.067 (4) | −0.017 (4) | 0.049 (4) | −0.009 (3) |
C13' | 0.068 (4) | 0.079 (5) | 0.064 (4) | −0.006 (4) | 0.002 (3) | −0.006 (3) |
O1—C7 | 1.220 (6) | C12—H12C | 0.9600 |
O2—C10 | 1.192 (6) | C13—H13A | 0.9600 |
O3—C10 | 1.330 (7) | C13—H13B | 0.9600 |
O3—H3 | 0.8200 | C13—H13C | 0.9600 |
O1'—C7' | 1.204 (6) | C1'—C2' | 1.520 (7) |
O2'—C10' | 1.201 (7) | C1'—C8'a | 1.530 (7) |
O3'—C10' | 1.318 (7) | C1'—H1'A | 0.9700 |
O3'—H3' | 0.8200 | C1'—H1'B | 0.9700 |
C1—C8a | 1.534 (7) | C2'—C3' | 1.524 (8) |
C1—C2 | 1.536 (6) | C2'—C9' | 1.540 (7) |
C1—H1A | 0.9700 | C2'—H2'A | 0.9800 |
C1—H1B | 0.9700 | C3'—C4' | 1.528 (8) |
C2—C3 | 1.526 (8) | C3'—H3'A | 0.9700 |
C2—C9 | 1.550 (7) | C3'—H3'B | 0.9700 |
C2—H2A | 0.9800 | C4'—C4'a | 1.534 (7) |
C3—C4 | 1.523 (7) | C4'—H4'A | 0.9700 |
C3—H3A | 0.9700 | C4'—H4'B | 0.9700 |
C3—H3B | 0.9700 | C4'a—C13' | 1.530 (7) |
C4—C4a | 1.539 (6) | C4'a—C5' | 1.536 (7) |
C4—H4A | 0.9700 | C4'a—C8'a | 1.544 (7) |
C4—H4B | 0.9700 | C5'—C6' | 1.511 (8) |
C4a—C13 | 1.522 (7) | C5'—H5'A | 0.9700 |
C4a—C8a | 1.533 (7) | C5'—H5'B | 0.9700 |
C4a—C5 | 1.537 (7) | C6'—C7' | 1.506 (8) |
C5—C6 | 1.531 (7) | C6'—H6'A | 0.9700 |
C5—H5A | 0.9700 | C6'—H6'B | 0.9700 |
C5—H5B | 0.9700 | C7'—C8' | 1.508 (7) |
C6—C7 | 1.492 (8) | C8'—C12' | 1.536 (7) |
C6—H6A | 0.9700 | C8'—C8'a | 1.541 (7) |
C6—H6B | 0.9700 | C8'—H8'A | 0.9800 |
C7—C8 | 1.509 (8) | C8'a—H8'B | 0.9800 |
C8—C12 | 1.523 (8) | C9'—C10' | 1.530 (9) |
C8—C8a | 1.550 (6) | C9'—C11' | 1.533 (7) |
C8—H8A | 0.9800 | C9'—H9'A | 0.9800 |
C8a—H8B | 0.9800 | C11'—H11D | 0.9600 |
C9—C10 | 1.491 (8) | C11'—H11E | 0.9600 |
C9—C11 | 1.539 (7) | C11'—H11F | 0.9600 |
C9—H9A | 0.9800 | C12'—H12D | 0.9600 |
C11—H11A | 0.9600 | C12'—H12E | 0.9600 |
C11—H11B | 0.9600 | C12'—H12F | 0.9600 |
C11—H11C | 0.9600 | C13'—H13D | 0.9600 |
C12—H12A | 0.9600 | C13'—H13E | 0.9600 |
C12—H12B | 0.9600 | C13'—H13F | 0.9600 |
C10—O3—H3 | 109.5 | H13B—C13—H13C | 109.5 |
C10'—O3'—H3' | 109.5 | C2'—C1'—C8'a | 112.3 (4) |
C8a—C1—C2 | 113.5 (4) | C2'—C1'—H1'A | 109.1 |
C8a—C1—H1A | 108.9 | C8'a—C1'—H1'A | 109.1 |
C2—C1—H1A | 108.9 | C2'—C1'—H1'B | 109.1 |
C8a—C1—H1B | 108.9 | C8'a—C1'—H1'B | 109.1 |
C2—C1—H1B | 108.9 | H1'A—C1'—H1'B | 107.9 |
H1A—C1—H1B | 107.7 | C1'—C2'—C3' | 110.3 (5) |
C3—C2—C1 | 111.0 (4) | C1'—C2'—C9' | 112.1 (4) |
C3—C2—C9 | 112.4 (4) | C3'—C2'—C9' | 113.4 (4) |
C1—C2—C9 | 109.8 (4) | C1'—C2'—H2'A | 106.9 |
C3—C2—H2A | 107.8 | C3'—C2'—H2'A | 106.9 |
C1—C2—H2A | 107.8 | C9'—C2'—H2'A | 106.9 |
C9—C2—H2A | 107.8 | C2'—C3'—C4' | 111.8 (4) |
C4—C3—C2 | 112.4 (4) | C2'—C3'—H3'A | 109.3 |
C4—C3—H3A | 109.1 | C4'—C3'—H3'A | 109.3 |
C2—C3—H3A | 109.1 | C2'—C3'—H3'B | 109.3 |
C4—C3—H3B | 109.1 | C4'—C3'—H3'B | 109.3 |
C2—C3—H3B | 109.1 | H3'A—C3'—H3'B | 107.9 |
H3A—C3—H3B | 107.8 | C3'—C4'—C4'a | 113.2 (5) |
C3—C4—C4a | 113.4 (4) | C3'—C4'—H4'A | 108.9 |
C3—C4—H4A | 108.9 | C4'a—C4'—H4'A | 108.9 |
C4a—C4—H4A | 108.9 | C3'—C4'—H4'B | 108.9 |
C3—C4—H4B | 108.9 | C4'a—C4'—H4'B | 108.9 |
C4a—C4—H4B | 108.9 | H4'A—C4'—H4'B | 107.8 |
H4A—C4—H4B | 107.7 | C13'—C4'a—C4' | 109.8 (4) |
C13—C4a—C8a | 114.3 (4) | C13'—C4'a—C5' | 109.4 (5) |
C13—C4a—C5 | 109.0 (5) | C4'—C4'a—C5' | 109.1 (5) |
C8a—C4a—C5 | 107.7 (4) | C13'—C4'a—C8'a | 112.6 (4) |
C13—C4a—C4 | 109.4 (4) | C4'—C4'a—C8'a | 108.1 (4) |
C8a—C4a—C4 | 106.8 (4) | C5'—C4'a—C8'a | 107.7 (4) |
C5—C4a—C4 | 109.5 (4) | C6'—C5'—C4'a | 114.0 (5) |
C6—C5—C4a | 111.6 (5) | C6'—C5'—H5'A | 108.8 |
C6—C5—H5A | 109.3 | C4'a—C5'—H5'A | 108.8 |
C4a—C5—H5A | 109.3 | C6'—C5'—H5'B | 108.8 |
C6—C5—H5B | 109.3 | C4'a—C5'—H5'B | 108.8 |
C4a—C5—H5B | 109.3 | H5'A—C5'—H5'B | 107.7 |
H5A—C5—H5B | 108.0 | C7'—C6'—C5' | 114.1 (5) |
C7—C6—C5 | 115.0 (5) | C7'—C6'—H6'A | 108.7 |
C7—C6—H6A | 108.5 | C5'—C6'—H6'A | 108.7 |
C5—C6—H6A | 108.5 | C7'—C6'—H6'B | 108.7 |
C7—C6—H6B | 108.5 | C5'—C6'—H6'B | 108.7 |
C5—C6—H6B | 108.5 | H6'A—C6'—H6'B | 107.6 |
H6A—C6—H6B | 107.5 | O1'—C7'—C6' | 122.0 (6) |
O1—C7—C6 | 120.9 (6) | O1'—C7'—C8' | 121.1 (5) |
O1—C7—C8 | 120.3 (6) | C6'—C7'—C8' | 116.9 (5) |
C6—C7—C8 | 118.8 (5) | C7'—C8'—C12' | 111.7 (4) |
C7—C8—C12 | 111.7 (5) | C7'—C8'—C8'a | 112.9 (4) |
C7—C8—C8a | 113.9 (4) | C12'—C8'—C8'a | 113.6 (5) |
C12—C8—C8a | 112.9 (5) | C7'—C8'—H8'A | 106.0 |
C7—C8—H8A | 105.8 | C12'—C8'—H8'A | 106.0 |
C12—C8—H8A | 105.8 | C8'a—C8'—H8'A | 106.0 |
C8a—C8—H8A | 105.8 | C1'—C8'a—C8' | 113.3 (4) |
C4a—C8a—C1 | 111.8 (4) | C1'—C8'a—C4'a | 112.2 (4) |
C4a—C8a—C8 | 112.9 (4) | C8'—C8'a—C4'a | 112.3 (4) |
C1—C8a—C8 | 110.5 (4) | C1'—C8'a—H8'B | 106.1 |
C4a—C8a—H8B | 107.1 | C8'—C8'a—H8'B | 106.1 |
C1—C8a—H8B | 107.1 | C4'a—C8'a—H8'B | 106.1 |
C8—C8a—H8B | 107.1 | C10'—C9'—C11' | 108.3 (6) |
C10—C9—C11 | 111.0 (5) | C10'—C9'—C2' | 109.4 (4) |
C10—C9—C2 | 110.6 (4) | C11'—C9'—C2' | 113.1 (5) |
C11—C9—C2 | 113.2 (5) | C10'—C9'—H9'A | 108.6 |
C10—C9—H9A | 107.2 | C11'—C9'—H9'A | 108.6 |
C11—C9—H9A | 107.2 | C2'—C9'—H9'A | 108.6 |
C2—C9—H9A | 107.2 | O2'—C10'—O3' | 124.7 (7) |
O2—C10—O3 | 121.8 (7) | O2'—C10'—C9' | 123.3 (7) |
O2—C10—C9 | 125.9 (7) | O3'—C10'—C9' | 112.0 (6) |
O3—C10—C9 | 112.2 (5) | C9'—C11'—H11D | 109.5 |
C9—C11—H11A | 109.5 | C9'—C11'—H11E | 109.5 |
C9—C11—H11B | 109.5 | H11D—C11'—H11E | 109.5 |
H11A—C11—H11B | 109.5 | C9'—C11'—H11F | 109.5 |
C9—C11—H11C | 109.5 | H11D—C11'—H11F | 109.5 |
H11A—C11—H11C | 109.5 | H11E—C11'—H11F | 109.5 |
H11B—C11—H11C | 109.5 | C8'—C12'—H12D | 109.5 |
C8—C12—H12A | 109.5 | C8'—C12'—H12E | 109.5 |
C8—C12—H12B | 109.5 | H12D—C12'—H12E | 109.5 |
H12A—C12—H12B | 109.5 | C8'—C12'—H12F | 109.5 |
C8—C12—H12C | 109.5 | H12D—C12'—H12F | 109.5 |
H12A—C12—H12C | 109.5 | H12E—C12'—H12F | 109.5 |
H12B—C12—H12C | 109.5 | C4'a—C13'—H13D | 109.5 |
C4a—C13—H13A | 109.5 | C4'a—C13'—H13E | 109.5 |
C4a—C13—H13B | 109.5 | H13D—C13'—H13E | 109.5 |
H13A—C13—H13B | 109.5 | C4'a—C13'—H13F | 109.5 |
C4a—C13—H13C | 109.5 | H13D—C13'—H13F | 109.5 |
H13A—C13—H13C | 109.5 | H13E—C13'—H13F | 109.5 |
C8a—C1—C2—C3 | 49.6 (6) | C8'a—C1'—C2'—C3' | 54.5 (6) |
C8a—C1—C2—C9 | 174.6 (4) | C8'a—C1'—C2'—C9' | −178.0 (5) |
C1—C2—C3—C4 | −49.0 (6) | C1'—C2'—C3'—C4' | −53.8 (6) |
C9—C2—C3—C4 | −172.5 (4) | C9'—C2'—C3'—C4' | 179.5 (5) |
C2—C3—C4—C4a | 55.9 (6) | C2'—C3'—C4'—C4'a | 56.1 (7) |
C3—C4—C4a—C13 | 65.6 (6) | C3'—C4'—C4'a—C13' | 68.2 (6) |
C3—C4—C4a—C8a | −58.6 (6) | C3'—C4'—C4'a—C5' | −171.9 (5) |
C3—C4—C4a—C5 | −175.0 (5) | C3'—C4'—C4'a—C8'a | −55.1 (6) |
C13—C4a—C5—C6 | −63.8 (6) | C13'—C4'a—C5'—C6' | −65.6 (6) |
C8a—C4a—C5—C6 | 60.7 (6) | C4'—C4'a—C5'—C6' | 174.2 (5) |
C4—C4a—C5—C6 | 176.5 (5) | C8'a—C4'a—C5'—C6' | 57.1 (6) |
C4a—C5—C6—C7 | −48.5 (7) | C4'a—C5'—C6'—C7' | −48.1 (7) |
C5—C6—C7—O1 | −148.3 (6) | C5'—C6'—C7'—O1' | −141.3 (6) |
C5—C6—C7—C8 | 33.9 (8) | C5'—C6'—C7'—C8' | 39.4 (7) |
O1—C7—C8—C12 | 21.0 (8) | O1'—C7'—C8'—C12' | 10.2 (8) |
C6—C7—C8—C12 | −161.2 (5) | C6'—C7'—C8'—C12' | −170.4 (5) |
O1—C7—C8—C8a | 150.4 (5) | O1'—C7'—C8'—C8'a | 139.7 (6) |
C6—C7—C8—C8a | −31.7 (7) | C6'—C7'—C8'—C8'a | −40.9 (7) |
C13—C4a—C8a—C1 | −63.5 (6) | C2'—C1'—C8'a—C8' | 175.0 (5) |
C5—C4a—C8a—C1 | 175.2 (4) | C2'—C1'—C8'a—C4'a | −56.6 (6) |
C4—C4a—C8a—C1 | 57.7 (5) | C7'—C8'—C8'a—C1' | 179.5 (4) |
C13—C4a—C8a—C8 | 61.8 (6) | C12'—C8'—C8'a—C1' | −51.9 (6) |
C5—C4a—C8a—C8 | −59.5 (6) | C7'—C8'—C8'a—C4'a | 51.1 (6) |
C4—C4a—C8a—C8 | −177.0 (4) | C12'—C8'—C8'a—C4'a | 179.7 (4) |
C2—C1—C8a—C4a | −55.8 (6) | C13'—C4'a—C8'a—C1' | −66.6 (6) |
C2—C1—C8a—C8 | 177.6 (4) | C4'—C4'a—C8'a—C1' | 54.9 (6) |
C7—C8—C8a—C4a | 45.1 (6) | C5'—C4'a—C8'a—C1' | 172.7 (5) |
C12—C8—C8a—C4a | 173.9 (5) | C13'—C4'a—C8'a—C8' | 62.4 (6) |
C7—C8—C8a—C1 | 171.1 (4) | C4'—C4'a—C8'a—C8' | −176.1 (4) |
C12—C8—C8a—C1 | −60.1 (6) | C5'—C4'a—C8'a—C8' | −58.3 (6) |
C3—C2—C9—C10 | 178.7 (5) | C1'—C2'—C9'—C10' | 54.1 (7) |
C1—C2—C9—C10 | 54.6 (6) | C3'—C2'—C9'—C10' | 179.9 (6) |
C3—C2—C9—C11 | −56.0 (6) | C1'—C2'—C9'—C11' | 175.0 (5) |
C1—C2—C9—C11 | 179.9 (5) | C3'—C2'—C9'—C11' | −59.3 (7) |
C11—C9—C10—O2 | 127.1 (6) | C11'—C9'—C10'—O2' | −66.6 (8) |
C2—C9—C10—O2 | −106.4 (7) | C2'—C9'—C10'—O2' | 57.1 (8) |
C11—C9—C10—O3 | −54.2 (7) | C11'—C9'—C10'—O3' | 116.1 (6) |
C2—C9—C10—O3 | 72.4 (6) | C2'—C9'—C10'—O3' | −120.2 (5) |
Experimental details
Crystal data | |
Chemical formula | C15H24O3 |
Mr | 252.34 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 296 |
a, b, c (Å) | 10.136 (3), 14.867 (4), 10.238 (3) |
β (°) | 111.36 (2) |
V (Å3) | 1436.8 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.25 × 0.22 × 0.07 |
Data collection | |
Diffractometer | Siemens P4 diffractometer |
Absorption correction | Numerical (SHELXTL; Sheldrick, 1997) |
Tmin, Tmax | 0.96, 0.99 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5322, 2590, 1462 |
Rint | 0.060 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.120, 1.05 |
No. of reflections | 2590 |
No. of parameters | 328 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.14, −0.13 |
Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXS97 in SHELXTL (Sheldrick, 1997), SHELXL97 in SHELXTL (Sheldrick, 1997), SHELXP97 in SHELXTL (Sheldrick, 1997), SHELXL97 in SHELXTL.
O2—C10 | 1.192 (6) | O2'—C10' | 1.201 (7) |
O3—C10 | 1.330 (7) | O3'—C10' | 1.318 (7) |
O2—C10—C9 | 125.9 (7) | O2'—C10'—C9' | 123.3 (7) |
O3—C10—C9 | 112.2 (5) | O3'—C10'—C9' | 112.0 (6) |
Our crystallographic study of keto acids explores the molecular characteristics that control their hydrogen-bonding modes. As we have illustrated previously, carboxyl dimerization is the commonest hydrogen-bonding pattern for achiral molecules and racemates, but is suppressed whenever centrosymmetry is precluded (Lalancette et al., 1998). In chiral nonracemates, then, formation of acid-to-ketone chains becomes the dominant hydrogen-bonding mode (Brunskill et al., 1997). The title compound, (I), derived from an anthelmintic sesquiterpenoid isolated from Artemisia, is a bicyclic ζ-keto acid, present as a single enantiomer. We have previously described the structures and hydrogen-bonding behaviors of two unsaturated keto acids related to (I), both of which were found to display catemeric acid-to-ketone hydrogen bonding (Brunskill et al., 2001, 2002). We now report that the same hydrogen-bonding mode is adopted in the solid state by (I), and that (I) is isostructural with one of the above cited compounds [Cambridge Structural Database (Allen, 2002), reference code AFUVEC; Brunskill et al., 2002]. \sch
Fig. 1 shows the asymmetric unit of (I), which, as in the case of AFUVEC, consists of two molecules, (IA) and (IB), the difference between which lies principally in the rotation of the carboxyl group about the C9—C10 bond. In both (IA) and (IB), the substituents at C9, which has the S configuration, are staggered with respect to those at C2, so that the methyl is anti to C1; the C11—C9—C2—C1 torsion angle is 179.9 (5)° in (IA) and 175.0 (5)° in (IB), a difference of only 4.9 (7)°. However, in (IA), the carboxyl group is rotated so that its C═O is turned toward the molecular face bearing the angular methyl (C13), a cisoid arrangement, in which the O3—C10—C9—C2 torsion angle is 72.4 (6)°, while in (IB), this relationship is transoid and the corresponding angle is −120.2 (5)°, a difference of 167.4 (8)°. An alternative measure of the conformation of the carboxyl group is provided by the dihedral angle for the O2—O3—C10—C9 carboxyl plane relative to the C10—C9—C2 plane, which is 72.9 (4)° for (IA) and 58.7 (4)° for (IB), yielding a difference of 14.2 (6)°. Despite this, the intramolecular ketone versus carboxyl dihedral angles for (IA) and (IB) differ by 26.1 (5)°. The apparent discrepancies among these various measures of carboxyl conformation arise in part because of the above-mentioned differential staggering around C9—C2, and in part because of significant flattening in the ketone ring in the case of (IA). This flattening is revealed in the dihedral angles for the plane of the ketone versus that for the adjacent portion of the ketone ring (O1/C7/C6/C8 versus C5/C6/C8/C8a). This angle is 28.4 (3)° for (IA) and 36.0 (3)° for (IB), a difference of 7.6 (4)°.
The averaging of C—O bond lengths and C—C—O angles by disorder, often seen in dimeric acids, is not observed in catemers. Hence, no significant averaging is observed for (IA), the C—O bond lengths of which are 1.192 (6) and 1.330 (7) Å, with C—C—O angles of 125.9 (6) and 112.2 (5)°; for (IB), the corresponding lengths are 1.201 (7) and 1.317 (7) Å, and the corresponding angles are 123.3 (7) and 112.0 (6)°. Our own survey of 56 non-dimeric keto acid structures gives average values of 1.200 (10) and 1.32 (2) Å, and 124.5 (14) and 112.7 (17)°, for these lengths and angles, in accord with typical values of 1.21 and 1.31 Å, and 123 and 112°, cited for highly ordered dimeric carboxyls (Borthwick, 1980). The three methyl groups present are fully ordered in both (IA) and (IB), and are staggered relative to the substituents at their points of attachment.
Fig. 2 illustrates the packing of (IA) and (IB) in the cell, and the formation of acid-to-ketone catemers, in which the intermolecular O···O distance and O—H···O angle are 2.715 (6) Å and 169°, respectively, within the type-(IA) chains, and 2.772 (6) Å and 168°, respectively, within the type-(IB) chains. The hydrogen-bonding arrangements of (IA) and (IB) and their differences adhere so closely to the isostructural case of AFUVEC that readers are referred for a fuller discussion to that presented by Brunskill et al. (2002).
Consistent with the 167.4 (8)° difference in carboxyl rotation and the observed flattening of the ketone ring in the two molecules of (I), but unlike the case of AFUVEC, the geometry of the hydrogen bonding itself displays significant differences between (IA) and (IB). 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 (IA), these angles are 119.8 and −27.1°, respectively, while in (IB), the same angles are 123.6 and 4.3°, respectively, the former approach being quite significantly out of the ketone plane.
However, molecules (IA) and (IB) lie so nearly parallel that, despite these differences, the overall shapes of the helices produced by their chain formation are remarkably close. Thus, the intermolecular ketone versus carboxyl dihedral angles for screw-related neighbors involved in hydrogen bonding are quite similar, at 113.9 (4)° for the type-(IA) chains and 123.6 (3)° for the type-(IB) chains. This is in marked contrast to the case of AFUVEC (Brunskill et al., 2001 Should this be 2002?), where the intermolecular dihedrals within its two types of helices differ much more dramatically. Compound (I) and AFUVEC are isostructural not only because they are isoskeletal, but also because of their strong similarity in shape. A major contributor to the latter is the trans ring juncture in (I), which, much more than would a cis arrangement, confers both a generally planar shape and a conformational rigidity closely resembling AFUVEC. In addition, the 8-methyl group in (I) has the (thermodynamically favored) equatorial configuration, again resembling its placement in AFUVEC far more than the axial alternative would.
Within the 2.7-?.?Å range we usually employ for non-bonded C—H···O packing interactions (Steiner, 1997), one intermolecular C—H···O═C close contact exists for the type-(IA) carboxyl, with a distance of 2.63 Å to atom H5'B in a type-(IB) molecule of a translationally related asymmetric unit. Using compiled data for a large number of C—H···O contacts, Steiner & Desiraju (1998) have found 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.
The solid-state (KBr) IR spectrum of (I) displays C═O absorptions at 1723 and 1678 cm−1, consistent with known hydrogen-bonding shifts, due to H-atom removal from acid C═O and addition to a saturated ketone, respectively. In CHCl3 solution, dimers predominate and these absorptions merge into a single peak at 1704 cm−1.