Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102004365/fr1365sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102004365/fr1365Isup2.hkl |
CCDC reference: 187922
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 the LiNH3 reductive procedure described by Bruderer et al. (1956) and Howe et al. (1959), who have also assigned the optical rotation. Crystals of (I) (m.p. 398 K) were obtained from an acetone–water solution.
The H atoms of molecules I and I were found in electron-density difference maps but were placed in calculated positions (0.96 Å for methyl, 0.97 Å for methylene and 0.98 Å for methine H atoms) and allowed to refine as riding models on their respective C atoms. The displacement parameters were fixed at 120% of those of their respective C atoms, except for the methyl H atoms, which were fixed at 150% of those of their respective C atoms. The postitional parameters of the carboxyl H atoms were allowed to refine, but their displacement parameters were fixed at 0.08 Å2. The absolute configuration was not directly determined, and Friedel pairs were averaged.
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.
C15H22O3 | Dx = 1.183 Mg m−3 |
Mr = 250.33 | Melting point: 398 K |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
a = 10.0225 (14) Å | Cell parameters from 25 reflections |
b = 14.862 (2) Å | θ = 4.5–13.8° |
c = 10.0873 (14) Å | µ = 0.08 mm−1 |
β = 110.758 (11)° | T = 296 K |
V = 1405.0 (3) Å3 | Parallelepiped, colourless |
Z = 4 | 0.44 × 0.30 × 0.22 mm |
F(000) = 544 |
Siemens P4 diffractometer | Rint = 0.029 |
Radiation source: fine-focus sealed tube | θmax = 25.0°, θmin = 2.2° |
Graphite monochromator | h = −11→11 |
2θ/θ scans | k = −17→17 |
5441 measured reflections | l = −11→11 |
2579 independent reflections | 3 standard reflections every 97 reflections |
1977 reflections with I > 2σ(I) | intensity decay: variation < 1.5% |
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)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0451P)2 + 0.1708P] where P = (Fo2 + 2Fc2)/3 |
2579 reflections | (Δ/σ)max < 0.001 |
337 parameters | Δρmax = 0.14 e Å−3 |
1 restraint | Δρmin = −0.10 e Å−3 |
C15H22O3 | V = 1405.0 (3) Å3 |
Mr = 250.33 | Z = 4 |
Monoclinic, P21 | Mo Kα radiation |
a = 10.0225 (14) Å | µ = 0.08 mm−1 |
b = 14.862 (2) Å | T = 296 K |
c = 10.0873 (14) Å | 0.44 × 0.30 × 0.22 mm |
β = 110.758 (11)° |
Siemens P4 diffractometer | Rint = 0.029 |
5441 measured reflections | 3 standard reflections every 97 reflections |
2579 independent reflections | intensity decay: variation < 1.5% |
1977 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.042 | 1 restraint |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.14 e Å−3 |
2579 reflections | Δρmin = −0.10 e Å−3 |
337 parameters |
x | y | z | Uiso*/Ueq | ||
O1 | 0.5796 (3) | 0.82699 (19) | 0.3203 (3) | 0.0803 (8) | |
O2 | 0.2136 (3) | 0.5202 (2) | 0.6780 (3) | 0.0838 (8) | |
O3 | 0.4239 (4) | 0.4810 (2) | 0.8324 (3) | 0.0856 (9) | |
C1 | 0.4028 (4) | 0.7012 (2) | 0.6672 (3) | 0.0556 (9) | |
C2 | 0.4504 (3) | 0.6838 (2) | 0.8276 (3) | 0.0479 (8) | |
C3 | 0.4758 (4) | 0.7724 (2) | 0.9070 (3) | 0.0556 (9) | |
C4 | 0.5732 (4) | 0.8340 (2) | 0.8626 (3) | 0.0587 (9) | |
C4A | 0.5191 (3) | 0.8568 (2) | 0.7043 (3) | 0.0510 (8) | |
C5 | 0.6333 (4) | 0.9097 (3) | 0.6718 (4) | 0.0631 (9) | |
C6 | 0.5978 (4) | 0.9218 (2) | 0.5129 (4) | 0.0642 (10) | |
C7 | 0.5667 (4) | 0.8344 (2) | 0.4359 (4) | 0.0568 (9) | |
C8 | 0.5119 (4) | 0.7600 (2) | 0.4970 (4) | 0.0603 (9) | |
C8A | 0.4885 (3) | 0.7694 (2) | 0.6204 (3) | 0.0511 (8) | |
C9 | 0.3395 (4) | 0.6243 (2) | 0.8613 (3) | 0.0524 (8) | |
C10 | 0.3158 (4) | 0.5367 (3) | 0.7803 (4) | 0.0590 (9) | |
C11 | 0.3770 (4) | 0.6068 (3) | 1.0196 (4) | 0.0704 (11) | |
C12 | 0.4927 (5) | 0.6721 (3) | 0.4177 (4) | 0.0753 (12) | |
C13 | 0.3832 (4) | 0.9138 (3) | 0.6673 (4) | 0.0713 (11) | |
O1' | 0.9312 (4) | 0.68963 (19) | 0.6684 (3) | 0.0870 (9) | |
O2' | 1.2432 (4) | 0.9889 (2) | 0.2969 (3) | 0.0945 (10) | |
O3' | 1.0430 (4) | 1.0506 (2) | 0.1547 (3) | 0.0899 (11) | |
C1' | 0.9853 (4) | 0.8318 (2) | 0.2603 (4) | 0.0591 (9) | |
C2' | 1.0897 (4) | 0.8203 (2) | 0.1815 (4) | 0.0567 (9) | |
C3' | 1.0515 (5) | 0.7354 (2) | 0.0906 (4) | 0.0705 (11) | |
C4' | 1.0497 (4) | 0.6549 (2) | 0.1819 (4) | 0.0659 (10) | |
C4A' | 0.9482 (4) | 0.6622 (2) | 0.2650 (3) | 0.0527 (8) | |
C5' | 0.9773 (4) | 0.5835 (2) | 0.3681 (4) | 0.0639 (10) | |
C6' | 0.9043 (4) | 0.5921 (2) | 0.4744 (4) | 0.0658 (10) | |
C7' | 0.9346 (4) | 0.6811 (2) | 0.5499 (4) | 0.0553 (9) | |
C8' | 0.9633 (4) | 0.7591 (2) | 0.4744 (3) | 0.0529 (8) | |
C8A' | 0.9714 (3) | 0.7511 (2) | 0.3449 (3) | 0.0508 (8) | |
C9' | 1.0952 (4) | 0.9048 (3) | 0.0969 (4) | 0.0629 (10) | |
C10' | 1.1376 (5) | 0.9849 (3) | 0.1943 (4) | 0.0637 (10) | |
C11' | 1.1982 (6) | 0.8962 (3) | 0.0169 (5) | 0.0985 (16) | |
C12' | 0.9820 (5) | 0.8470 (2) | 0.5546 (4) | 0.0658 (10) | |
C13' | 0.7921 (4) | 0.6592 (3) | 0.1618 (4) | 0.0828 (13) | |
H3 | 0.403 (4) | 0.432 (3) | 0.781 (5) | 0.080* | |
H1A | 0.4059 | 0.6445 | 0.6206 | 0.067* | |
H1B | 0.3042 | 0.7209 | 0.6339 | 0.067* | |
H2A | 0.5410 | 0.6509 | 0.8568 | 0.058* | |
H3A | 0.5182 | 0.7608 | 1.0080 | 0.067* | |
H3B | 0.3851 | 0.8023 | 0.8894 | 0.067* | |
H4A | 0.6661 | 0.8057 | 0.8876 | 0.070* | |
H4B | 0.5857 | 0.8896 | 0.9161 | 0.070* | |
H5A | 0.7238 | 0.8785 | 0.7118 | 0.076* | |
H5B | 0.6434 | 0.9684 | 0.7165 | 0.076* | |
H6A | 0.5155 | 0.9610 | 0.4755 | 0.077* | |
H6B | 0.6776 | 0.9506 | 0.4968 | 0.077* | |
H9A | 0.2487 | 0.6570 | 0.8282 | 0.063* | |
H11A | 0.3817 | 0.6630 | 1.0680 | 0.106* | |
H11B | 0.4678 | 0.5771 | 1.0567 | 0.106* | |
H11C | 0.3051 | 0.5694 | 1.0336 | 0.106* | |
H12A | 0.5271 | 0.6781 | 0.3406 | 0.113* | |
H12B | 0.3933 | 0.6565 | 0.3811 | 0.113* | |
H12C | 0.5453 | 0.6257 | 0.4808 | 0.113* | |
H13A | 0.4041 | 0.9685 | 0.7216 | 0.107* | |
H13B | 0.3114 | 0.8807 | 0.6891 | 0.107* | |
H13C | 0.3491 | 0.9281 | 0.5680 | 0.107* | |
H3' | 1.064 (4) | 1.092 (3) | 0.213 (5) | 0.080* | |
H1'A | 1.0158 | 0.8828 | 0.3239 | 0.071* | |
H1'B | 0.8919 | 0.8459 | 0.1916 | 0.071* | |
H2'A | 1.1850 | 0.8114 | 0.2529 | 0.068* | |
H3'A | 0.9584 | 0.7427 | 0.0171 | 0.085* | |
H3'B | 1.1209 | 0.7259 | 0.0452 | 0.085* | |
H4'A | 1.1456 | 0.6453 | 0.2489 | 0.079* | |
H4'B | 1.0235 | 0.6021 | 0.1216 | 0.079* | |
H5'A | 0.9458 | 0.5284 | 0.3146 | 0.077* | |
H5'B | 1.0794 | 0.5788 | 0.4183 | 0.077* | |
H6'A | 0.8021 | 0.5856 | 0.4263 | 0.079* | |
H6'B | 0.9363 | 0.5440 | 0.5435 | 0.079* | |
H9'A | 0.9995 | 0.9158 | 0.0276 | 0.075* | |
H11D | 1.1653 | 0.8499 | −0.0536 | 0.148* | |
H11E | 1.2914 | 0.8808 | 0.0822 | 0.148* | |
H11F | 1.2029 | 0.9524 | −0.0282 | 0.148* | |
H12D | 0.9987 | 0.8350 | 0.6527 | 0.099* | |
H12E | 0.8972 | 0.8827 | 0.5154 | 0.099* | |
H12F | 1.0619 | 0.8792 | 0.5466 | 0.099* | |
H13D | 0.7764 | 0.7064 | 0.0930 | 0.124* | |
H13E | 0.7292 | 0.6672 | 0.2138 | 0.124* | |
H13F | 0.7735 | 0.6020 | 0.1144 | 0.124* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.126 (2) | 0.0705 (18) | 0.0657 (16) | −0.0136 (17) | 0.0599 (17) | 0.0019 (15) |
O2 | 0.0721 (17) | 0.096 (2) | 0.0763 (18) | −0.0099 (17) | 0.0178 (15) | −0.0227 (17) |
O3 | 0.116 (2) | 0.0689 (19) | 0.0636 (17) | 0.0261 (19) | 0.0212 (17) | −0.0067 (15) |
C1 | 0.072 (2) | 0.055 (2) | 0.0417 (17) | −0.0102 (18) | 0.0222 (16) | −0.0069 (16) |
C2 | 0.0521 (19) | 0.0507 (19) | 0.0426 (17) | 0.0079 (15) | 0.0186 (14) | 0.0011 (14) |
C3 | 0.071 (2) | 0.057 (2) | 0.0404 (16) | 0.0056 (18) | 0.0216 (16) | −0.0011 (16) |
C4 | 0.073 (2) | 0.055 (2) | 0.0444 (17) | 0.0016 (18) | 0.0167 (17) | −0.0069 (16) |
C4A | 0.056 (2) | 0.0491 (19) | 0.0470 (17) | 0.0043 (16) | 0.0176 (16) | 0.0002 (15) |
C5 | 0.076 (2) | 0.057 (2) | 0.059 (2) | −0.009 (2) | 0.0261 (19) | −0.0079 (18) |
C6 | 0.082 (3) | 0.053 (2) | 0.066 (2) | −0.009 (2) | 0.037 (2) | −0.0009 (18) |
C7 | 0.070 (2) | 0.057 (2) | 0.0475 (19) | 0.0027 (18) | 0.0262 (17) | 0.0013 (17) |
C8 | 0.085 (2) | 0.053 (2) | 0.0492 (17) | −0.0079 (19) | 0.0324 (17) | −0.0046 (18) |
C8A | 0.059 (2) | 0.0530 (19) | 0.0444 (17) | −0.0070 (17) | 0.0216 (16) | −0.0050 (16) |
C9 | 0.060 (2) | 0.057 (2) | 0.0448 (17) | 0.0099 (17) | 0.0242 (16) | 0.0035 (16) |
C10 | 0.072 (2) | 0.067 (2) | 0.0475 (19) | 0.001 (2) | 0.0318 (19) | 0.0062 (19) |
C11 | 0.095 (3) | 0.072 (3) | 0.0512 (19) | 0.003 (2) | 0.036 (2) | 0.0036 (19) |
C12 | 0.119 (3) | 0.062 (2) | 0.061 (2) | −0.014 (2) | 0.050 (2) | −0.0103 (19) |
C13 | 0.080 (3) | 0.067 (2) | 0.071 (2) | 0.023 (2) | 0.032 (2) | 0.008 (2) |
O1' | 0.153 (3) | 0.0549 (16) | 0.0711 (17) | −0.0089 (18) | 0.0613 (18) | −0.0008 (15) |
O2' | 0.092 (2) | 0.095 (2) | 0.085 (2) | 0.0072 (19) | 0.0190 (18) | −0.0098 (19) |
O3' | 0.142 (3) | 0.0634 (19) | 0.0619 (17) | 0.0302 (19) | 0.0327 (18) | −0.0016 (15) |
C1' | 0.082 (2) | 0.0446 (19) | 0.059 (2) | 0.0144 (18) | 0.0347 (19) | 0.0021 (17) |
C2' | 0.075 (2) | 0.0486 (19) | 0.0513 (19) | 0.0159 (18) | 0.0277 (17) | 0.0041 (16) |
C3' | 0.102 (3) | 0.058 (2) | 0.062 (2) | 0.014 (2) | 0.042 (2) | −0.0025 (19) |
C4' | 0.089 (3) | 0.048 (2) | 0.061 (2) | 0.0158 (19) | 0.028 (2) | −0.0053 (17) |
C4A' | 0.063 (2) | 0.0426 (18) | 0.0482 (18) | 0.0084 (16) | 0.0139 (16) | −0.0043 (15) |
C5' | 0.092 (3) | 0.0409 (18) | 0.056 (2) | 0.0051 (19) | 0.023 (2) | −0.0051 (16) |
C6' | 0.087 (3) | 0.046 (2) | 0.067 (2) | −0.005 (2) | 0.030 (2) | 0.0002 (18) |
C7' | 0.061 (2) | 0.049 (2) | 0.056 (2) | 0.0021 (17) | 0.0210 (16) | 0.0022 (17) |
C8' | 0.065 (2) | 0.0426 (19) | 0.0529 (19) | 0.0038 (17) | 0.0232 (17) | 0.0021 (16) |
C8A' | 0.055 (2) | 0.0423 (18) | 0.0552 (19) | 0.0084 (16) | 0.0198 (16) | 0.0032 (16) |
C9' | 0.087 (3) | 0.057 (2) | 0.052 (2) | 0.016 (2) | 0.0341 (19) | 0.0072 (18) |
C10' | 0.088 (3) | 0.058 (2) | 0.059 (2) | 0.011 (2) | 0.043 (2) | 0.0100 (19) |
C11' | 0.157 (5) | 0.081 (3) | 0.092 (3) | 0.006 (3) | 0.086 (3) | 0.006 (3) |
C12' | 0.091 (3) | 0.048 (2) | 0.064 (2) | −0.0030 (19) | 0.034 (2) | −0.0056 (17) |
C13' | 0.081 (3) | 0.079 (3) | 0.068 (2) | 0.002 (2) | 0.001 (2) | −0.003 (2) |
O1—C7 | 1.223 (4) | C2—H2A | 0.9800 |
O2—C10 | 1.193 (4) | C3—H3A | 0.9700 |
O3—C10 | 1.316 (5) | C3—H3B | 0.9700 |
C1—C8A | 1.509 (5) | C4—H4A | 0.9700 |
C1—C2 | 1.538 (4) | C4—H4B | 0.9700 |
C2—C3 | 1.516 (5) | C5—H5A | 0.9700 |
C2—C9 | 1.549 (5) | C5—H5B | 0.9700 |
C3—C4 | 1.517 (5) | C6—H6A | 0.9700 |
C4—C4A | 1.531 (4) | C6—H6B | 0.9700 |
C4A—C5 | 1.517 (5) | C9—H9A | 0.9800 |
C4A—C8A | 1.521 (5) | C11—H11A | 0.9600 |
C4A—C13 | 1.534 (5) | C11—H11B | 0.9600 |
C5—C6 | 1.524 (5) | C11—H11C | 0.9600 |
C6—C7 | 1.489 (5) | C12—H12A | 0.9600 |
C7—C8 | 1.464 (5) | C12—H12B | 0.9600 |
C8—C8A | 1.353 (5) | C12—H12C | 0.9600 |
C8—C12 | 1.508 (5) | C13—H13A | 0.9600 |
C9—C10 | 1.511 (5) | C13—H13B | 0.9600 |
C9—C11 | 1.528 (4) | C13—H13C | 0.9600 |
O1'—C7' | 1.215 (4) | O3'—H3' | 0.82 (5) |
O2'—C10' | 1.190 (5) | C1'—H1'A | 0.9700 |
O3'—C10' | 1.320 (5) | C1'—H1'B | 0.9700 |
C1'—C8A' | 1.506 (5) | C2'—H2'A | 0.9800 |
C1'—C2' | 1.530 (5) | C3'—H3'A | 0.9700 |
C2'—C3' | 1.526 (5) | C3'—H3'B | 0.9700 |
C2'—C9' | 1.532 (5) | C4'—H4'A | 0.9700 |
C3'—C4' | 1.515 (5) | C4'—H4'B | 0.9700 |
C4'—C4A' | 1.534 (5) | C5'—H5'A | 0.9700 |
C4A'—C8A' | 1.522 (4) | C5'—H5'B | 0.9700 |
C4A'—C5' | 1.523 (5) | C6'—H6'A | 0.9700 |
C4A'—C13' | 1.542 (5) | C6'—H6'B | 0.9700 |
C5'—C6' | 1.503 (5) | C9'—H9'A | 0.9800 |
C6'—C7' | 1.502 (5) | C11'—H11D | 0.9600 |
C7'—C8' | 1.471 (5) | C11'—H11E | 0.9600 |
C8'—C8A' | 1.342 (5) | C11'—H11F | 0.9600 |
C8'—C12' | 1.513 (5) | C12'—H12D | 0.9600 |
C9'—C10' | 1.506 (6) | C12'—H12E | 0.9600 |
C9'—C11' | 1.524 (5) | C12'—H12F | 0.9600 |
O3—H3 | 0.87 (4) | C13'—H13D | 0.9600 |
C1—H1A | 0.9700 | C13'—H13E | 0.9600 |
C1—H1B | 0.9700 | C13'—H13F | 0.9600 |
C8A—C1—C2 | 116.4 (3) | C4A—C5—H5B | 109.2 |
C3—C2—C1 | 110.0 (3) | C6—C5—H5B | 109.2 |
C3—C2—C9 | 112.3 (3) | H5A—C5—H5B | 107.9 |
C1—C2—C9 | 110.4 (3) | C7—C6—H6A | 109.2 |
C2—C3—C4 | 111.9 (3) | C5—C6—H6A | 109.2 |
C3—C4—C4A | 114.4 (3) | C7—C6—H6B | 109.2 |
C5—C4A—C8A | 109.9 (3) | C5—C6—H6B | 109.2 |
C5—C4A—C4 | 108.9 (3) | H6A—C6—H6B | 107.9 |
C8A—C4A—C4 | 108.6 (3) | C10—C9—H9A | 107.1 |
C5—C4A—C13 | 109.5 (3) | C11—C9—H9A | 107.1 |
C8A—C4A—C13 | 110.5 (3) | C2—C9—H9A | 107.1 |
C4—C4A—C13 | 109.4 (3) | C9—C11—H11A | 109.5 |
C4A—C5—C6 | 112.1 (3) | C9—C11—H11B | 109.5 |
C7—C6—C5 | 111.9 (3) | H11A—C11—H11B | 109.5 |
O1—C7—C8 | 121.0 (3) | C9—C11—H11C | 109.5 |
O1—C7—C6 | 120.2 (3) | H11A—C11—H11C | 109.5 |
C8—C7—C6 | 118.7 (3) | H11B—C11—H11C | 109.5 |
C8A—C8—C7 | 121.5 (3) | C8—C12—H12A | 109.5 |
C8A—C8—C12 | 123.1 (3) | C8—C12—H12B | 109.5 |
C7—C8—C12 | 115.3 (3) | H12A—C12—H12B | 109.5 |
C8—C8A—C1 | 121.5 (3) | C8—C12—H12C | 109.5 |
C8—C8A—C4A | 122.3 (3) | H12A—C12—H12C | 109.5 |
C1—C8A—C4A | 115.1 (3) | H12B—C12—H12C | 109.5 |
C10—C9—C11 | 110.6 (3) | C4A—C13—H13A | 109.5 |
C10—C9—C2 | 111.2 (3) | C4A—C13—H13B | 109.5 |
C11—C9—C2 | 113.4 (3) | H13A—C13—H13B | 109.5 |
O2—C10—O3 | 123.4 (4) | C4A—C13—H13C | 109.5 |
O2—C10—C9 | 124.5 (4) | H13A—C13—H13C | 109.5 |
O3—C10—C9 | 112.1 (3) | H13B—C13—H13C | 109.5 |
C8A'—C1'—C2' | 115.0 (3) | C10'—O3'—H3' | 111 (3) |
C3'—C2'—C1' | 109.4 (3) | C8A'—C1'—H1'A | 108.5 |
C3'—C2'—C9' | 113.2 (3) | C2'—C1'—H1'A | 108.5 |
C1'—C2'—C9' | 111.4 (3) | C8A'—C1'—H1'B | 108.5 |
C4'—C3'—C2' | 110.0 (3) | C2'—C1'—H1'B | 108.5 |
C3'—C4'—C4A' | 115.4 (3) | H1'A—C1'—H1'B | 107.5 |
C8A'—C4A'—C5' | 110.4 (3) | C3'—C2'—H2'A | 107.5 |
C8A'—C4A'—C4' | 110.2 (3) | C1'—C2'—H2'A | 107.5 |
C5'—C4A'—C4' | 108.3 (3) | C9'—C2'—H2'A | 107.5 |
C8A'—C4A'—C13' | 108.1 (3) | C4'—C3'—H3'A | 109.7 |
C5'—C4A'—C13' | 110.0 (3) | C2'—C3'—H3'A | 109.7 |
C4'—C4A'—C13' | 109.9 (3) | C4'—C3'—H3'B | 109.7 |
C6'—C5'—C4A' | 113.5 (3) | C2'—C3'—H3'B | 109.7 |
C7'—C6'—C5' | 112.0 (3) | H3'A—C3'—H3'B | 108.2 |
O1'—C7'—C8' | 120.4 (3) | C3'—C4'—H4'A | 108.4 |
O1'—C7'—C6' | 121.3 (3) | C4A'—C4'—H4'A | 108.4 |
C8'—C7'—C6' | 118.3 (3) | C3'—C4'—H4'B | 108.4 |
C8A'—C8'—C7' | 121.6 (3) | C4A'—C4'—H4'B | 108.4 |
C8A'—C8'—C12' | 123.9 (3) | H4'A—C4'—H4'B | 107.5 |
C7'—C8'—C12' | 114.5 (3) | C6'—C5'—H5'A | 108.9 |
C8'—C8A'—C1' | 122.1 (3) | C4A'—C5'—H5'A | 108.9 |
C8'—C8A'—C4A' | 122.8 (3) | C6'—C5'—H5'B | 108.9 |
C1'—C8A'—C4A' | 114.7 (3) | C4A'—C5'—H5'B | 108.9 |
C10'—C9'—C11' | 109.0 (4) | H5'A—C5'—H5'B | 107.7 |
C10'—C9'—C2' | 110.0 (3) | C7'—C6'—H6'A | 109.2 |
C11'—C9'—C2' | 113.0 (3) | C5'—C6'—H6'A | 109.2 |
O2'—C10'—O3' | 123.2 (4) | C7'—C6'—H6'B | 109.2 |
O2'—C10'—C9' | 124.4 (4) | C5'—C6'—H6'B | 109.2 |
O3'—C10'—C9' | 112.4 (4) | H6'A—C6'—H6'B | 107.9 |
C10—O3—H3 | 107 (3) | C10'—C9'—H9'A | 108.2 |
C8A—C1—H1A | 108.2 | C11'—C9'—H9'A | 108.2 |
C2—C1—H1A | 108.2 | C2'—C9'—H9'A | 108.2 |
C8A—C1—H1B | 108.2 | C9'—C11'—H11D | 109.5 |
C2—C1—H1B | 108.2 | C9'—C11'—H11E | 109.5 |
H1A—C1—H1B | 107.4 | H11D—C11'—H11E | 109.5 |
C3—C2—H2A | 108.0 | C9'—C11'—H11F | 109.5 |
C1—C2—H2A | 108.0 | H11D—C11'—H11F | 109.5 |
C9—C2—H2A | 108.0 | H11E—C11'—H11F | 109.5 |
C2—C3—H3A | 109.2 | C8'—C12'—H12D | 109.5 |
C4—C3—H3A | 109.2 | C8'—C12'—H12E | 109.5 |
C2—C3—H3B | 109.2 | H12D—C12'—H12E | 109.5 |
C4—C3—H3B | 109.2 | C8'—C12'—H12F | 109.5 |
H3A—C3—H3B | 107.9 | H12D—C12'—H12F | 109.5 |
C3—C4—H4A | 108.6 | H12E—C12'—H12F | 109.5 |
C4A—C4—H4A | 108.6 | C4A'—C13'—H13D | 109.5 |
C3—C4—H4B | 108.6 | C4A'—C13'—H13E | 109.5 |
C4A—C4—H4B | 108.6 | H13D—C13'—H13E | 109.5 |
H4A—C4—H4B | 107.6 | C4A'—C13'—H13F | 109.5 |
C4A—C5—H5A | 109.2 | H13D—C13'—H13F | 109.5 |
C6—C5—H5A | 109.2 | H13E—C13'—H13F | 109.5 |
C8A—C1—C2—C3 | 46.7 (4) | C8A'—C1'—C2'—C3' | 53.3 (4) |
C8A—C1—C2—C9 | 171.1 (3) | C8A'—C1'—C2'—C9' | 179.2 (3) |
C1—C2—C3—C4 | −51.1 (4) | C1'—C2'—C3'—C4' | −55.7 (4) |
C9—C2—C3—C4 | −174.4 (3) | C9'—C2'—C3'—C4' | 179.4 (3) |
C2—C3—C4—C4A | 58.2 (4) | C2'—C3'—C4'—C4A' | 57.1 (5) |
C3—C4—C4A—C5 | −173.7 (3) | C3'—C4'—C4A'—C8A' | −50.1 (4) |
C3—C4—C4A—C8A | −54.0 (4) | C3'—C4'—C4A'—C5' | −170.9 (3) |
C3—C4—C4A—C13 | 66.7 (4) | C3'—C4'—C4A'—C13' | 69.0 (4) |
C8A—C4A—C5—C6 | 51.8 (4) | C8A'—C4A'—C5'—C6' | 48.6 (4) |
C4—C4A—C5—C6 | 170.7 (3) | C4'—C4A'—C5'—C6' | 169.3 (3) |
C13—C4A—C5—C6 | −69.7 (4) | C13'—C4A'—C5'—C6' | −70.6 (4) |
C4A—C5—C6—C7 | −53.3 (4) | C4A'—C5'—C6'—C7' | −52.0 (4) |
C5—C6—C7—O1 | −157.4 (4) | C5'—C6'—C7'—O1' | −153.2 (4) |
C5—C6—C7—C8 | 26.5 (5) | C5'—C6'—C7'—C8' | 29.0 (5) |
O1—C7—C8—C8A | −175.6 (4) | O1'—C7'—C8'—C8A' | 178.2 (4) |
C6—C7—C8—C8A | 0.4 (6) | C6'—C7'—C8'—C8A' | −4.0 (5) |
O1—C7—C8—C12 | 7.9 (6) | O1'—C7'—C8'—C12' | −2.0 (5) |
C6—C7—C8—C12 | −176.0 (4) | C6'—C7'—C8'—C12' | 175.8 (3) |
C7—C8—C8A—C1 | 166.3 (3) | C7'—C8'—C8A'—C1' | 173.4 (3) |
C12—C8—C8A—C1 | −17.5 (6) | C12'—C8'—C8A'—C1' | −6.4 (5) |
C7—C8—C8A—C4A | −0.9 (6) | C7'—C8'—C8A'—C4A' | 1.5 (5) |
C12—C8—C8A—C4A | 175.3 (4) | C12'—C8'—C8A'—C4A' | −178.3 (3) |
C2—C1—C8A—C8 | 145.3 (3) | C2'—C1'—C8A'—C8' | 138.9 (3) |
C2—C1—C8A—C4A | −46.7 (4) | C2'—C1'—C8A'—C4A' | −48.7 (4) |
C5—C4A—C8A—C8 | −25.5 (5) | C5'—C4A'—C8A'—C8' | −23.6 (5) |
C4—C4A—C8A—C8 | −144.6 (3) | C4'—C4A'—C8A'—C8' | −143.2 (3) |
C13—C4A—C8A—C8 | 95.4 (4) | C13'—C4A'—C8A'—C8' | 96.7 (4) |
C5—C4A—C8A—C1 | 166.6 (3) | C5'—C4A'—C8A'—C1' | 164.0 (3) |
C4—C4A—C8A—C1 | 47.5 (4) | C4'—C4A'—C8A'—C1' | 44.4 (4) |
C13—C4A—C8A—C1 | −72.5 (4) | C13'—C4A'—C8A'—C1' | −75.7 (4) |
C3—C2—C9—C10 | 179.8 (3) | C3'—C2'—C9'—C10' | −178.3 (3) |
C1—C2—C9—C10 | 56.7 (4) | C1'—C2'—C9'—C10' | 57.9 (4) |
C3—C2—C9—C11 | −54.9 (4) | C3'—C2'—C9'—C11' | −56.3 (5) |
C1—C2—C9—C11 | −178.0 (3) | C1'—C2'—C9'—C11' | 179.9 (3) |
C11—C9—C10—O2 | 129.2 (4) | C11'—C9'—C10'—O2' | −69.0 (5) |
C2—C9—C10—O2 | −104.0 (4) | C2'—C9'—C10'—O2' | 55.4 (5) |
C11—C9—C10—O3 | −53.2 (4) | C11'—C9'—C10'—O3' | 112.0 (4) |
C2—C9—C10—O3 | 73.7 (4) | C2'—C9'—C10'—O3' | −123.6 (4) |
Experimental details
Crystal data | |
Chemical formula | C15H22O3 |
Mr | 250.33 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 296 |
a, b, c (Å) | 10.0225 (14), 14.862 (2), 10.0873 (14) |
β (°) | 110.758 (11) |
V (Å3) | 1405.0 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.44 × 0.30 × 0.22 |
Data collection | |
Diffractometer | Siemens P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5441, 2579, 1977 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.105, 1.03 |
No. of reflections | 2579 |
No. of parameters | 337 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.14, −0.10 |
Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL (Sheldrick, 1997), SHELXTL.
O2—C10 | 1.193 (4) | O2'—C10' | 1.190 (5) |
O3—C10 | 1.316 (5) | O3'—C10' | 1.320 (5) |
O2—C10—C9 | 124.5 (4) | O2'—C10'—C9' | 124.4 (4) |
O3—C10—C9 | 112.1 (3) | O3'—C10'—C9' | 112.4 (4) |
C1—C2—C9—C11 | −178.0 (3) | C1'—C2'—C9'—C11' | 179.9 (3) |
C2—C9—C10—O3 | 73.7 (4) | C2'—C9'—C10'—O3' | −123.6 (4) |
Our crystallographic studies of keto carboxylic acids explore the molecular characteristics that control their hydrogen-bonding patterns. Functionally unelaborated acids commonly aggregate in the solid as dimers, rarely as catemers (chains). An added ketone function provides opportunities for at least three additional hydrogen-bonding modes, the commonest of which, the acid-to-ketone catemer, forms a sizable overall minority of keto acid hydrogen-bonding cases. As we have previously suggested, carboxyl dimerization is suppressed in monoenantiomeric species (Lalancette et al., 1998) and by the presence of conformational restrictions (Brunskill et al., 1999). In the presence of such molecular features, catemer formation may become the dominant hydrogen-bonding mode (Brunskill et al., 1997).
The title compound (1), derived from a sesquiterpenoid isolate of Artemisia, is a bicyclic ζ-keto acid, present as a single enantiomer. We have previously (Brunskill et al., 2001) described a related diketo-dienoic acid (plus its hydrate) and Khanina et al. (1998) have recently published the X-ray structure of the Δ9 - 11 derivative of (I). Both those compounds display catemeric carboxyl-to-ketone hydrogen bonding, and we report here that (I) also adopts this hydrogen-bonding mode in the solid state.
Fig. 1 shows the asymmetric unit, consisting of two molecules, I and I', which differ principally in the rotation of the carboxyl group about the C9—C10 bond. The substituents at C9, which has an S configuration, are staggered with respect to those at C2, so that the methyl group is anti to C1; the C1—C2—C9—C11 torsion angle is -178.0 (3)° in molecule I and 179.9 (3)° in molecule I', a difference of only 2.1 (4)°. However, in I, the carboxyl group is rotated so that its C═O is turned toward the molecular face bearing the angular methyl group, a cisoid arrangement, in which the C2—C9—C10—O3 torsion angle is 73.7 (4)°, while in I', this relationship is transoid and the corresponding angle is -123.6 (4)°, a difference of 162.7 (6)°.
The partial averaging of C—O bond lengths and C—C—O angles by disorder often seen in acids occurs only in the carboxyl-pairing hydrogen-bonding mode. As in other catemers, no significant averaging is observed for molecule I, whose bond lengths are 1.193 (4)/1.316 (5) Å, with angles of 124.5 (4)/112.1 (3)°; for molecule I', these values are 1.190 (5)/1.320 (5) Å and 124.4 (4)/112.4 (4)°. Our own survey of 56 keto acid structures which are not acid dimers gives average values of 1.200 (10)/1.32 (2) Å and 124.5 (14)/112.7 (17)° for these lengths and angles, in accord with typical values of 1.21/1.31 Å and 123/112° cited for highly ordered dimeric carboxyls (Borthwick, 1980). The three methyl groups are fully ordered in molecules I and I', and atoms C11 and C13 are staggered relative to the substituents at their points of attachment.
Fig. 2 illustrates the packing of molecules I and I' in the cell, with extracellular molecules included to show the two crystallographically independent single-strand hydrogen-bonding catemers, in which each chain proceeds from the carboxyl group of one molecule to the ketone group of a neighbor of its own type. Among such catemers, the observed prevalence of subtypes, describing the relation of adjacent molecules, is screw > translation > glide. Here, adjacent intrachain units are related by a twofold screw along b; helices of type-I follow an axis through the cell center, while the axis for the counterdirectionally aligned type-I' helices lies in the bc face of the chosen cell.
Consistent with the difference found between molecules I and I' for the rotation of the COOH group about C9—C10, the intramolecular ketone versus carboxyl dihedral angles for I and I' differ only by 11.04 (14)°. The intermolecular ketone versus carboxyl dihedral angles for adjacent hydrogen-bonded molecules are also similar, at 65.06 (15)° for the type-I chains and 57.67 (15)° for the type-I' chains.
Considering the difference of 162.7 (6)° in carboxyl rotation, the geometry of the hydrogen bonding itself for I versus I' adheres remarkably closely to standard patterns for O—H···O═C situations. 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 group (ideal = 0°). In molecule I, these angles are 119.9 (13) and -14 (2)°, respectively, while in molecule I', the they are 122.9 (13) and 16 (2)°, respectively.
Three intermolecular C—H···O close contacts exist, all for the type-I carboxyl C═O group, within the 2.7 Å range we usually employ for non-bonded C—H···O packing interactions (Steiner, 1997). These involve H5'B (2.63 Å) and H6'B (2.65 Å) within the same type-I' molecule, related translationally in a, plus H6B (2.59 Å) in a type-I molecule, its own hydrogen-bonding partner, screw related in b. 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.
The KBr IR spectrum of (I) displays absorptions at 1726 and 1627 cm-1, consistent with known hydrogen-bonding shifts due, respectively, to its removal from acid C═O and its addition to an unsaturated ketone; a minor peak appears at 1675 cm-1 and a shoulder at ca 1599 cm-1 (C═C). In CHCl3 solution, where dimers predominate, the major peaks appear, more normally, at 1708 and 1656 cm-1, with a smaller C═C peak at 1608 cm-1 and a typical carboxyl-dilution shoulder near 1750 cm-1.