Three cyclooctitol derivatives, in the form of a tetraacetate, (1
S*,2
R*,3
S*,4
S*)-2,3,4-triacetoxycyclooctan-1-ylmethyl acetate, C
17H
26O
8, and two regioisomeric acetonide triacetates, (3a
S*,4
R*,8
S*,9
S*,9a
S*)-8,9-diacetoxy-2,2-dimethylcyclooctano[
d][1,3]dioxan-4-ymethyl acetate and (3a
S,4
R,7
S,9
R,9a
S)-7,9-diacetoxy-2,2-dimethylcyclooctano[
d][1,3]dioxan-4-ylmethyl acetate, both C
18H
28O
8, have been studied. The conformation of the cyclooctane ring in the three compounds is quite close to the boat–chair form of the parent hydrocarbon. Packing is effected through weak C—H
O and van der Waals contacts.
Supporting information
CCDC references: 672548; 672549; 672550
####The cyclooctitol derivatives (I)–(III) were prepared as previously reported
(Mehta & Pallavi, 2002). Crystals of (I)–(III), suitable for single-crystal
X-ray diffraction analysis, were grown from their dilute solutions in a 1:2
dichloromethane–petroleum ether mixture by slow solvent evaporation.
All H atoms were initially located in a difference Fourier map. The methine (CH)
and methylene (CH2) H atoms were then placed in geometrically idealized
positions and allowed to ride on their parent atoms with C—H distances of
0.97 and 0.98 Å and Uiso(H) values of 1.2Ueq(C). The
methyl H atoms were not well defined in difference maps and were constrained
to an ideal geometry with a C—H distance of 0.96 Å and Uiso(H)
values of 1.5Ueq(C). During refinement, each methyl group was allowed
to rotate freely about its C—C bond.
For all compounds, data collection: SMART (Bruker, 1998). Cell refinement: SAINT (Bruker, 1998) for (I), (II); SMART (Bruker, 1998) for (III). For all compounds, data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: PLATON (Spek, 2003).
(I) (1
S*,2
R*,3
S*,4
S*)-2,3,4-triacetoxycyclooctan-1-ylmethyl acetate
top
Crystal data top
C17H26O8 | Z = 2 |
Mr = 358.38 | F(000) = 384 |
Triclinic, P1 | Dx = 1.255 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.1632 (9) Å | Cell parameters from 3830 reflections |
b = 9.2131 (9) Å | θ = 2.3–27.2° |
c = 11.5904 (11) Å | µ = 0.10 mm−1 |
α = 94.709 (2)° | T = 291 K |
β = 92.486 (2)° | Block, colorless |
γ = 102.912 (2)° | 0.35 × 0.31 × 0.28 mm |
V = 948.60 (16) Å3 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 3500 independent reflections |
Radiation source: fine-focus sealed tube | 2880 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.019 |
ϕ and ω scans | θmax = 25.5°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −11→11 |
Tmin = 0.936, Tmax = 0.973 | k = −11→11 |
9524 measured reflections | l = −14→14 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.136 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0713P)2 + 0.2015P] where P = (Fo2 + 2Fc2)/3 |
3500 reflections | (Δ/σ)max < 0.001 |
230 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
Crystal data top
C17H26O8 | γ = 102.912 (2)° |
Mr = 358.38 | V = 948.60 (16) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.1632 (9) Å | Mo Kα radiation |
b = 9.2131 (9) Å | µ = 0.10 mm−1 |
c = 11.5904 (11) Å | T = 291 K |
α = 94.709 (2)° | 0.35 × 0.31 × 0.28 mm |
β = 92.486 (2)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 3500 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2880 reflections with I > 2σ(I) |
Tmin = 0.936, Tmax = 0.973 | Rint = 0.019 |
9524 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.136 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.32 e Å−3 |
3500 reflections | Δρmin = −0.25 e Å−3 |
230 parameters | |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. Four outlier reflections (3,5,4; 1,5,4; 3,5,1 & 2,4,0) were omitted from the
refinement. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.08290 (14) | −0.27858 (13) | 0.64446 (11) | 0.0558 (3) | |
O2 | 0.39354 (12) | −0.00780 (12) | 0.71670 (9) | 0.0431 (3) | |
O3 | 0.21602 (13) | 0.21760 (13) | 0.84362 (10) | 0.0525 (3) | |
O4 | 0.50109 (13) | 0.29004 (13) | 0.80950 (11) | 0.0549 (3) | |
O5 | 0.1437 (2) | −0.49528 (18) | 0.59574 (18) | 0.0971 (6) | |
O6 | 0.32805 (19) | −0.0823 (2) | 0.88951 (14) | 0.0927 (6) | |
O7 | −0.02687 (16) | 0.1234 (2) | 0.79527 (15) | 0.0824 (5) | |
O8 | 0.5895 (2) | 0.53633 (18) | 0.83651 (18) | 0.1099 (7) | |
C1 | 0.18533 (18) | −0.04200 (18) | 0.57279 (14) | 0.0458 (4) | |
C2 | 0.24739 (17) | 0.02391 (17) | 0.69560 (14) | 0.0412 (4) | |
C3 | 0.25241 (18) | 0.19096 (17) | 0.72402 (14) | 0.0434 (4) | |
C4 | 0.39964 (19) | 0.30473 (18) | 0.71365 (16) | 0.0481 (4) | |
C5 | 0.47793 (19) | 0.2891 (2) | 0.60217 (16) | 0.0522 (4) | |
C6 | 0.3929 (2) | 0.3070 (2) | 0.49114 (18) | 0.0594 (5) | |
C7 | 0.2531 (2) | 0.1873 (2) | 0.45203 (17) | 0.0579 (5) | |
C8 | 0.2625 (2) | 0.0262 (2) | 0.46816 (15) | 0.0542 (4) | |
C9 | 0.1765 (2) | −0.2093 (2) | 0.55887 (16) | 0.0541 (4) | |
C10 | 0.0756 (2) | −0.4235 (2) | 0.65305 (18) | 0.0623 (5) | |
C11 | −0.0309 (4) | −0.4824 (3) | 0.7399 (3) | 0.1075 (10) | |
C12 | 0.4205 (2) | −0.0590 (2) | 0.81891 (16) | 0.0554 (5) | |
C13 | 0.5756 (2) | −0.0812 (3) | 0.83197 (19) | 0.0703 (6) | |
C14 | 0.0719 (2) | 0.1760 (2) | 0.86732 (19) | 0.0586 (5) | |
C15 | 0.0541 (3) | 0.2038 (3) | 0.9943 (2) | 0.0897 (8) | |
C16 | 0.5868 (2) | 0.4139 (2) | 0.86471 (19) | 0.0666 (5) | |
C17 | 0.6809 (3) | 0.3798 (3) | 0.9613 (2) | 0.0966 (9) | |
H1 | 0.0817 | −0.0303 | 0.5659 | 0.055* | |
H2 | 0.1809 | −0.0304 | 0.7495 | 0.049* | |
H3 | 0.1751 | 0.2168 | 0.6738 | 0.052* | |
H4 | 0.3802 | 0.4053 | 0.7229 | 0.058* | |
H5A | 0.5725 | 0.3629 | 0.6091 | 0.063* | |
H5B | 0.5011 | 0.1912 | 0.5950 | 0.063* | |
H6A | 0.4614 | 0.3122 | 0.4293 | 0.071* | |
H6B | 0.3645 | 0.4024 | 0.5004 | 0.071* | |
H7A | 0.2296 | 0.1937 | 0.3705 | 0.069* | |
H7B | 0.1703 | 0.2091 | 0.4943 | 0.069* | |
H8A | 0.3676 | 0.0229 | 0.4756 | 0.065* | |
H8B | 0.2185 | −0.0366 | 0.3984 | 0.065* | |
H9A | 0.1348 | −0.2508 | 0.4817 | 0.065* | |
H9B | 0.2761 | −0.2279 | 0.5689 | 0.065* | |
H11A | −0.0622 | −0.5892 | 0.7254 | 0.161* | |
H11B | −0.1169 | −0.4394 | 0.7342 | 0.161* | |
H11C | 0.0174 | −0.4567 | 0.8163 | 0.161* | |
H13A | 0.6112 | −0.0607 | 0.9121 | 0.105* | |
H13B | 0.6398 | −0.0146 | 0.7864 | 0.105* | |
H13C | 0.5761 | −0.1827 | 0.8059 | 0.105* | |
H15A | −0.0504 | 0.1774 | 1.0090 | 0.134* | |
H15B | 0.0940 | 0.3077 | 1.0191 | 0.134* | |
H15C | 0.1072 | 0.1440 | 1.0364 | 0.134* | |
H17A | 0.7285 | 0.4709 | 1.0073 | 0.145* | |
H17B | 0.7561 | 0.3326 | 0.9305 | 0.145* | |
H17C | 0.6191 | 0.3138 | 1.0088 | 0.145* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0617 (8) | 0.0398 (6) | 0.0653 (8) | 0.0106 (5) | 0.0148 (6) | −0.0012 (5) |
O2 | 0.0450 (6) | 0.0440 (6) | 0.0430 (6) | 0.0137 (5) | 0.0056 (5) | 0.0081 (5) |
O3 | 0.0532 (7) | 0.0500 (7) | 0.0520 (7) | 0.0093 (5) | 0.0105 (5) | −0.0052 (5) |
O4 | 0.0510 (7) | 0.0452 (7) | 0.0640 (8) | 0.0031 (5) | −0.0032 (6) | 0.0052 (6) |
O5 | 0.1223 (15) | 0.0640 (10) | 0.1197 (14) | 0.0469 (10) | 0.0361 (12) | 0.0088 (9) |
O6 | 0.0842 (11) | 0.1445 (16) | 0.0643 (10) | 0.0401 (11) | 0.0227 (8) | 0.0483 (10) |
O7 | 0.0501 (8) | 0.1106 (13) | 0.0809 (11) | 0.0069 (8) | 0.0139 (8) | 0.0030 (9) |
O8 | 0.1387 (17) | 0.0506 (10) | 0.1218 (16) | −0.0079 (10) | −0.0423 (13) | 0.0067 (9) |
C1 | 0.0423 (9) | 0.0464 (9) | 0.0479 (9) | 0.0099 (7) | 0.0025 (7) | 0.0001 (7) |
C2 | 0.0382 (8) | 0.0406 (8) | 0.0453 (9) | 0.0090 (6) | 0.0072 (6) | 0.0045 (7) |
C3 | 0.0422 (8) | 0.0421 (9) | 0.0466 (9) | 0.0113 (7) | 0.0062 (7) | 0.0018 (7) |
C4 | 0.0473 (9) | 0.0383 (8) | 0.0589 (10) | 0.0096 (7) | 0.0030 (8) | 0.0065 (7) |
C5 | 0.0427 (9) | 0.0483 (9) | 0.0656 (11) | 0.0061 (7) | 0.0090 (8) | 0.0142 (8) |
C6 | 0.0596 (11) | 0.0597 (11) | 0.0633 (12) | 0.0161 (9) | 0.0128 (9) | 0.0208 (9) |
C7 | 0.0546 (10) | 0.0711 (12) | 0.0514 (10) | 0.0172 (9) | 0.0049 (8) | 0.0172 (9) |
C8 | 0.0552 (10) | 0.0604 (11) | 0.0453 (9) | 0.0106 (8) | 0.0035 (8) | 0.0018 (8) |
C9 | 0.0546 (10) | 0.0495 (10) | 0.0554 (10) | 0.0081 (8) | 0.0091 (8) | −0.0047 (8) |
C10 | 0.0779 (13) | 0.0467 (10) | 0.0646 (12) | 0.0206 (9) | 0.0045 (10) | 0.0000 (9) |
C11 | 0.162 (3) | 0.0584 (14) | 0.104 (2) | 0.0189 (16) | 0.056 (2) | 0.0150 (13) |
C12 | 0.0627 (11) | 0.0609 (11) | 0.0455 (10) | 0.0180 (9) | 0.0052 (8) | 0.0108 (8) |
C13 | 0.0724 (13) | 0.0880 (15) | 0.0588 (12) | 0.0345 (11) | −0.0029 (10) | 0.0144 (11) |
C14 | 0.0568 (11) | 0.0492 (10) | 0.0701 (12) | 0.0110 (8) | 0.0210 (10) | 0.0021 (9) |
C15 | 0.1029 (19) | 0.0821 (16) | 0.0773 (16) | 0.0059 (14) | 0.0417 (14) | −0.0084 (12) |
C16 | 0.0660 (12) | 0.0543 (12) | 0.0692 (13) | −0.0071 (9) | −0.0009 (10) | 0.0050 (10) |
C17 | 0.0948 (19) | 0.0936 (19) | 0.0832 (17) | −0.0148 (14) | −0.0268 (14) | 0.0185 (14) |
Geometric parameters (Å, º) top
O1—C10 | 1.334 (2) | C6—H6A | 0.9700 |
O1—C9 | 1.436 (2) | C6—H6B | 0.9700 |
O2—C12 | 1.344 (2) | C7—C8 | 1.532 (3) |
O2—C2 | 1.4480 (18) | C7—H7A | 0.9700 |
O3—C14 | 1.338 (2) | C7—H7B | 0.9700 |
O3—C3 | 1.454 (2) | C8—H8A | 0.9700 |
O4—C16 | 1.328 (2) | C8—H8B | 0.9700 |
O4—C4 | 1.452 (2) | C9—H9A | 0.9700 |
O5—C10 | 1.190 (2) | C9—H9B | 0.9700 |
O6—C12 | 1.201 (2) | C10—C11 | 1.482 (3) |
O7—C14 | 1.193 (3) | C11—H11A | 0.9600 |
O8—C16 | 1.195 (3) | C11—H11B | 0.9600 |
C1—C9 | 1.520 (2) | C11—H11C | 0.9600 |
C1—C2 | 1.534 (2) | C12—C13 | 1.483 (3) |
C1—C8 | 1.538 (2) | C13—H13A | 0.9600 |
C1—H1 | 0.9800 | C13—H13B | 0.9600 |
C2—C3 | 1.537 (2) | C13—H13C | 0.9600 |
C2—H2 | 0.9800 | C14—C15 | 1.495 (3) |
C3—C4 | 1.528 (2) | C15—H15A | 0.9600 |
C3—H3 | 0.9800 | C15—H15B | 0.9600 |
C4—C5 | 1.517 (3) | C15—H15C | 0.9600 |
C4—H4 | 0.9800 | C16—C17 | 1.480 (3) |
C5—C6 | 1.515 (3) | C17—H17A | 0.9600 |
C5—H5A | 0.9700 | C17—H17B | 0.9600 |
C5—H5B | 0.9700 | C17—H17C | 0.9600 |
C6—C7 | 1.517 (3) | | |
| | | |
O1—C9—C1 | 108.74 (13) | C6—C5—H5B | 108.2 |
O1—C10—C11 | 111.12 (18) | C6—C7—H7A | 108.3 |
O1—C9—H9A | 109.9 | C6—C7—H7B | 108.3 |
O1—C9—H9B | 109.9 | C7—C8—C1 | 116.02 (15) |
O2—C2—C1 | 108.94 (12) | C7—C6—H6A | 108.0 |
O2—C2—C3 | 111.27 (12) | C7—C6—H6B | 108.0 |
O2—C12—C13 | 111.79 (16) | C7—C8—H8A | 108.3 |
O2—C2—H2 | 106.8 | C7—C8—H8B | 108.3 |
O3—C3—C2 | 109.65 (12) | C8—C1—H1 | 106.3 |
O3—C3—C4 | 104.46 (13) | C8—C7—H7A | 108.3 |
O3—C14—C15 | 110.8 (2) | C8—C7—H7B | 108.3 |
O3—C3—H3 | 107.9 | C9—C1—C2 | 110.27 (14) |
O4—C4—C3 | 106.89 (13) | C9—C1—C8 | 107.91 (14) |
O4—C4—C5 | 108.02 (13) | C9—C1—H1 | 106.3 |
O4—C16—C17 | 111.48 (19) | C10—O1—C9 | 116.82 (14) |
O4—C4—H4 | 108.4 | C10—C11—H11A | 109.5 |
O5—C10—O1 | 123.6 (2) | C10—C11—H11B | 109.5 |
O5—C10—C11 | 125.2 (2) | C10—C11—H11C | 109.5 |
O6—C12—O2 | 122.65 (18) | C12—O2—C2 | 116.98 (13) |
O6—C12—C13 | 125.56 (18) | C12—C13—H13A | 109.5 |
O7—C14—O3 | 123.40 (19) | C12—C13—H13B | 109.5 |
O7—C14—C15 | 125.8 (2) | C12—C13—H13C | 109.5 |
O8—C16—O4 | 123.4 (2) | C14—O3—C3 | 117.32 (14) |
O8—C16—C17 | 125.1 (2) | C14—C15—H15A | 109.5 |
C1—C2—C3 | 115.66 (13) | C14—C15—H15B | 109.5 |
C1—C2—H2 | 106.8 | C14—C15—H15C | 109.5 |
C1—C8—H8A | 108.3 | C16—O4—C4 | 118.24 (15) |
C1—C8—H8B | 108.3 | C16—C17—H17A | 109.5 |
C1—C9—H9A | 109.9 | C16—C17—H17B | 109.5 |
C1—C9—H9B | 109.9 | C16—C17—H17C | 109.5 |
C2—C1—C8 | 119.04 (14) | H5A—C5—H5B | 107.3 |
C2—C1—H1 | 106.3 | H6A—C6—H6B | 107.2 |
C2—C3—H3 | 107.9 | H7A—C7—H7B | 107.4 |
C3—C2—H2 | 106.8 | H8A—C8—H8B | 107.4 |
C3—C4—H4 | 108.4 | H9A—C9—H9B | 108.3 |
C4—C3—C2 | 118.71 (13) | H11A—C11—H11B | 109.5 |
C4—C3—H3 | 107.9 | H11A—C11—H11C | 109.5 |
C4—C5—H5A | 108.2 | H11B—C11—H11C | 109.5 |
C4—C5—H5B | 108.2 | H13A—C13—H13B | 109.5 |
C5—C4—C3 | 116.57 (15) | H13A—C13—H13C | 109.5 |
C5—C6—C7 | 117.39 (15) | H13B—C13—H13C | 109.5 |
C5—C4—H4 | 108.4 | H15A—C15—H15B | 109.5 |
C5—C6—H6A | 108.0 | H15A—C15—H15C | 109.5 |
C5—C6—H6B | 108.0 | H15B—C15—H15C | 109.5 |
C6—C5—C4 | 116.57 (15) | H17A—C17—H17B | 109.5 |
C6—C7—C8 | 115.85 (15) | H17A—C17—H17C | 109.5 |
C6—C5—H5A | 108.2 | H17B—C17—H17C | 109.5 |
| | | |
O2—C2—C3—O3 | −92.05 (14) | C4—C5—C6—C7 | −67.7 (2) |
O2—C2—C3—C4 | 27.8 (2) | C5—C6—C7—C8 | −39.7 (2) |
O3—C3—C4—O4 | 50.57 (16) | C6—C7—C8—C1 | 101.90 (19) |
O3—C3—C4—C5 | 171.46 (13) | C8—C1—C2—O2 | −67.74 (18) |
O4—C4—C5—C6 | −177.73 (14) | C8—C1—C2—C3 | 58.4 (2) |
C1—C2—C3—O3 | 142.95 (14) | C8—C1—C9—O1 | −170.34 (14) |
C1—C2—C3—C4 | −97.19 (17) | C9—O1—C10—O5 | 1.4 (3) |
C2—O2—C12—O6 | 2.1 (3) | C9—O1—C10—C11 | −176.9 (2) |
C2—O2—C12—C13 | −177.67 (15) | C9—C1—C2—O2 | 57.71 (16) |
C2—C1—C8—C7 | −65.8 (2) | C9—C1—C2—C3 | −176.11 (13) |
C2—C1—C9—O1 | 58.12 (18) | C9—C1—C8—C7 | 167.59 (15) |
C2—C3—C4—O4 | −71.91 (18) | C10—O1—C9—C1 | −173.02 (15) |
C2—C3—C4—C5 | 49.0 (2) | C12—O2—C2—C1 | −134.39 (15) |
C3—O3—C14—O7 | −2.4 (3) | C12—O2—C2—C3 | 96.94 (16) |
C3—O3—C14—C15 | 177.18 (16) | C14—O3—C3—C4 | 156.07 (15) |
C3—C4—C5—C6 | 62.0 (2) | C14—O3—C3—C2 | −75.70 (17) |
C4—O4—C16—O8 | −3.3 (3) | C16—O4—C4—C5 | 94.67 (18) |
C4—O4—C16—C17 | 178.76 (19) | C16—O4—C4—C3 | −139.15 (16) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···O6i | 0.96 | 2.53 | 3.439 (3) | 158 |
Symmetry code: (i) −x+1, −y, −z+2. |
(II) (3aS*,4
R*,8
S*,9
S*,9aS*)-8,9-diacetoxy-2,2-dimethylcyclooctano[
d][1,3]dioxan- 4-ylmethyl acetate
top
Crystal data top
C18H28O8 | F(000) = 1600 |
Mr = 372.40 | Dx = 1.249 Mg m−3 |
Orthorhombic, Pccn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ab 2ac | Cell parameters from 6079 reflections |
a = 19.206 (12) Å | θ = 2.5–23.2° |
b = 26.611 (17) Å | µ = 0.10 mm−1 |
c = 7.748 (5) Å | T = 291 K |
V = 3960 (4) Å3 | Block, colorless |
Z = 8 | 0.49 × 0.40 × 0.39 mm |
Data collection top
Bruker SMART CCD area-detector diffractometer | 3822 independent reflections |
Radiation source: fine-focus sealed tube | 2811 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.053 |
ϕ and ω scans | θmax = 26.0°, θmin = 1.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −23→23 |
Tmin = 0.905, Tmax = 0.963 | k = −32→31 |
24680 measured reflections | l = −9→9 |
Refinement top
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)] = 0.042 | H-atom parameters constrained |
wR(F2) = 0.111 | w = 1/[σ2(Fo2) + (0.0537P)2 + 0.5339P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
3822 reflections | Δρmax = 0.20 e Å−3 |
241 parameters | Δρmin = −0.14 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0070 (7) |
Crystal data top
C18H28O8 | V = 3960 (4) Å3 |
Mr = 372.40 | Z = 8 |
Orthorhombic, Pccn | Mo Kα radiation |
a = 19.206 (12) Å | µ = 0.10 mm−1 |
b = 26.611 (17) Å | T = 291 K |
c = 7.748 (5) Å | 0.49 × 0.40 × 0.39 mm |
Data collection top
Bruker SMART CCD area-detector diffractometer | 3822 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2811 reflections with I > 2σ(I) |
Tmin = 0.905, Tmax = 0.963 | Rint = 0.053 |
24680 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.20 e Å−3 |
3822 reflections | Δρmin = −0.14 e Å−3 |
241 parameters | |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.36504 (7) | 0.03567 (4) | 0.57587 (15) | 0.0572 (3) | |
O2 | 0.37167 (6) | 0.16104 (4) | 0.33097 (14) | 0.0485 (3) | |
O3 | 0.42318 (6) | 0.15849 (5) | 0.06869 (15) | 0.0573 (3) | |
O4 | 0.55129 (6) | 0.09492 (4) | −0.00990 (14) | 0.0545 (3) | |
O5 | 0.63693 (6) | 0.15585 (5) | 0.17851 (18) | 0.0599 (4) | |
O6 | 0.28183 (10) | 0.03769 (6) | 0.7786 (3) | 0.1044 (6) | |
O7 | 0.56806 (11) | 0.01831 (6) | 0.1032 (2) | 0.0927 (5) | |
O8 | 0.65717 (8) | 0.21449 (7) | −0.0215 (3) | 0.1084 (7) | |
C1 | 0.44384 (9) | 0.10386 (6) | 0.5024 (2) | 0.0466 (4) | |
C2 | 0.40687 (8) | 0.11323 (6) | 0.32878 (19) | 0.0426 (4) | |
C3 | 0.44821 (9) | 0.11430 (6) | 0.15464 (19) | 0.0460 (4) | |
C4 | 0.52782 (9) | 0.11449 (6) | 0.1571 (2) | 0.0459 (4) | |
C5 | 0.56172 (8) | 0.16590 (6) | 0.1733 (2) | 0.0498 (4) | |
C6 | 0.54235 (10) | 0.19576 (6) | 0.3339 (2) | 0.0566 (5) | |
C7 | 0.54956 (10) | 0.16793 (7) | 0.5068 (2) | 0.0605 (5) | |
C8 | 0.48163 (10) | 0.14897 (7) | 0.5859 (2) | 0.0558 (5) | |
C9 | 0.39077 (10) | 0.08430 (7) | 0.6343 (2) | 0.0558 (5) | |
C10 | 0.31114 (11) | 0.01621 (8) | 0.6648 (3) | 0.0657 (5) | |
C11 | 0.29365 (13) | −0.03550 (8) | 0.6004 (3) | 0.0794 (6) | |
C12 | 0.36064 (9) | 0.17491 (7) | 0.1549 (2) | 0.0504 (4) | |
C13 | 0.35623 (12) | 0.23183 (8) | 0.1452 (3) | 0.0775 (6) | |
C14 | 0.29713 (10) | 0.14911 (9) | 0.0788 (3) | 0.0723 (6) | |
C15 | 0.56993 (10) | 0.04642 (7) | −0.0192 (3) | 0.0579 (5) | |
C16 | 0.59024 (13) | 0.03250 (9) | −0.2002 (3) | 0.0849 (7) | |
C17 | 0.67830 (10) | 0.18315 (7) | 0.0761 (3) | 0.0612 (5) | |
C18 | 0.75396 (11) | 0.16998 (9) | 0.0991 (3) | 0.0801 (6) | |
H1 | 0.4784 | 0.0773 | 0.4841 | 0.056* | |
H2 | 0.3709 | 0.0873 | 0.3172 | 0.051* | |
H3 | 0.4333 | 0.0852 | 0.0866 | 0.055* | |
H4 | 0.5446 | 0.0926 | 0.2498 | 0.055* | |
H5 | 0.5509 | 0.1859 | 0.0705 | 0.060* | |
H6A | 0.4945 | 0.2068 | 0.3222 | 0.068* | |
H6B | 0.5714 | 0.2256 | 0.3381 | 0.068* | |
H7B | 0.5803 | 0.1394 | 0.4901 | 0.073* | |
H7A | 0.5718 | 0.1903 | 0.5889 | 0.073* | |
H8A | 0.4492 | 0.1769 | 0.5877 | 0.067* | |
H8B | 0.4912 | 0.1402 | 0.7051 | 0.067* | |
H9A | 0.4126 | 0.0809 | 0.7465 | 0.067* | |
H9B | 0.3524 | 0.1078 | 0.6447 | 0.067* | |
H11A | 0.2635 | −0.0519 | 0.6815 | 0.119* | |
H11B | 0.3357 | −0.0547 | 0.5877 | 0.119* | |
H11C | 0.2706 | −0.0330 | 0.4907 | 0.119* | |
H13A | 0.3149 | 0.2430 | 0.2031 | 0.116* | |
H13B | 0.3547 | 0.2421 | 0.0266 | 0.116* | |
H13C | 0.3963 | 0.2463 | 0.2000 | 0.116* | |
H14A | 0.3030 | 0.1133 | 0.0851 | 0.108* | |
H14B | 0.2918 | 0.1590 | −0.0397 | 0.108* | |
H14C | 0.2564 | 0.1587 | 0.1427 | 0.108* | |
H16A | 0.6248 | 0.0065 | −0.1970 | 0.127* | |
H16B | 0.6089 | 0.0615 | −0.2579 | 0.127* | |
H16C | 0.5500 | 0.0207 | −0.2615 | 0.127* | |
H18A | 0.7792 | 0.1786 | −0.0037 | 0.120* | |
H18B | 0.7583 | 0.1346 | 0.1203 | 0.120* | |
H18C | 0.7726 | 0.1883 | 0.1952 | 0.120* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0677 (8) | 0.0580 (7) | 0.0459 (7) | 0.0006 (6) | 0.0129 (6) | 0.0107 (5) |
O2 | 0.0550 (7) | 0.0517 (6) | 0.0387 (6) | 0.0092 (5) | 0.0003 (5) | 0.0046 (5) |
O3 | 0.0481 (7) | 0.0809 (8) | 0.0430 (6) | 0.0048 (6) | 0.0039 (5) | 0.0207 (6) |
O4 | 0.0655 (8) | 0.0517 (7) | 0.0463 (6) | 0.0091 (6) | 0.0155 (5) | 0.0031 (5) |
O5 | 0.0425 (7) | 0.0692 (8) | 0.0681 (8) | 0.0016 (6) | 0.0030 (6) | 0.0177 (6) |
O6 | 0.1149 (14) | 0.0836 (10) | 0.1146 (14) | 0.0059 (9) | 0.0697 (12) | 0.0064 (9) |
O7 | 0.1433 (16) | 0.0661 (9) | 0.0687 (9) | 0.0340 (9) | −0.0128 (9) | 0.0078 (7) |
O8 | 0.0637 (10) | 0.1253 (14) | 0.1362 (16) | 0.0088 (9) | 0.0157 (10) | 0.0750 (13) |
C1 | 0.0494 (9) | 0.0519 (9) | 0.0384 (8) | 0.0086 (7) | 0.0012 (7) | 0.0028 (7) |
C2 | 0.0448 (9) | 0.0437 (8) | 0.0393 (8) | −0.0005 (7) | 0.0019 (7) | 0.0031 (6) |
C3 | 0.0512 (10) | 0.0517 (9) | 0.0353 (8) | −0.0034 (7) | 0.0013 (7) | −0.0009 (7) |
C4 | 0.0506 (9) | 0.0501 (9) | 0.0370 (8) | 0.0029 (7) | 0.0047 (7) | 0.0028 (6) |
C5 | 0.0394 (9) | 0.0542 (9) | 0.0557 (10) | 0.0010 (7) | −0.0008 (7) | 0.0070 (7) |
C6 | 0.0520 (11) | 0.0512 (9) | 0.0667 (11) | −0.0047 (8) | −0.0028 (8) | −0.0044 (8) |
C7 | 0.0563 (11) | 0.0693 (11) | 0.0560 (11) | −0.0020 (9) | −0.0105 (9) | −0.0134 (9) |
C8 | 0.0610 (11) | 0.0661 (11) | 0.0404 (9) | 0.0068 (9) | −0.0048 (8) | −0.0060 (8) |
C9 | 0.0672 (12) | 0.0595 (10) | 0.0406 (9) | 0.0087 (9) | 0.0088 (8) | 0.0049 (7) |
C10 | 0.0676 (13) | 0.0679 (12) | 0.0616 (11) | 0.0091 (10) | 0.0185 (10) | 0.0225 (9) |
C11 | 0.0847 (16) | 0.0777 (14) | 0.0758 (14) | −0.0104 (12) | 0.0116 (12) | 0.0168 (11) |
C12 | 0.0472 (10) | 0.0636 (10) | 0.0404 (9) | 0.0021 (8) | −0.0010 (7) | 0.0116 (7) |
C13 | 0.0831 (15) | 0.0685 (12) | 0.0809 (14) | 0.0069 (11) | −0.0155 (11) | 0.0253 (11) |
C14 | 0.0518 (11) | 0.1020 (16) | 0.0631 (12) | −0.0047 (11) | −0.0098 (9) | 0.0054 (11) |
C15 | 0.0555 (11) | 0.0578 (10) | 0.0603 (11) | 0.0130 (8) | −0.0002 (9) | −0.0037 (9) |
C16 | 0.0927 (17) | 0.0835 (14) | 0.0786 (15) | 0.0155 (13) | 0.0258 (13) | −0.0182 (12) |
C17 | 0.0504 (11) | 0.0695 (11) | 0.0636 (11) | 0.0008 (9) | 0.0058 (9) | 0.0098 (9) |
C18 | 0.0496 (11) | 0.1068 (16) | 0.0840 (15) | 0.0002 (12) | 0.0068 (11) | 0.0154 (12) |
Geometric parameters (Å, º) top
O1—C10 | 1.347 (2) | C7—C8 | 1.527 (3) |
O1—C9 | 1.457 (2) | C7—H7B | 0.9700 |
O2—C12 | 1.429 (2) | C7—H7A | 0.9700 |
O2—C2 | 1.441 (2) | C8—H8A | 0.9700 |
O3—C3 | 1.434 (2) | C8—H8B | 0.9700 |
O3—C12 | 1.442 (2) | C9—H9A | 0.9700 |
O4—C15 | 1.341 (2) | C9—H9B | 0.9700 |
O4—C4 | 1.466 (2) | C10—C11 | 1.502 (3) |
O5—C17 | 1.338 (2) | C11—H11A | 0.9600 |
O5—C5 | 1.470 (2) | C11—H11B | 0.9600 |
O6—C10 | 1.192 (3) | C11—H11C | 0.9600 |
O7—C15 | 1.208 (2) | C12—C14 | 1.519 (3) |
O8—C17 | 1.197 (2) | C12—C13 | 1.519 (3) |
C1—C9 | 1.534 (2) | C13—H13A | 0.9600 |
C1—C2 | 1.542 (2) | C13—H13B | 0.9600 |
C1—C8 | 1.545 (2) | C13—H13C | 0.9600 |
C1—H1 | 0.9800 | C14—H14A | 0.9600 |
C2—C3 | 1.566 (2) | C14—H14B | 0.9600 |
C2—H2 | 0.9800 | C14—H14C | 0.9600 |
C3—C4 | 1.529 (3) | C15—C16 | 1.502 (3) |
C3—H3 | 0.9800 | C16—H16A | 0.9600 |
C4—C5 | 1.520 (2) | C16—H16B | 0.9600 |
C4—H4 | 0.9800 | C16—H16C | 0.9600 |
C5—C6 | 1.523 (3) | C17—C18 | 1.505 (3) |
C5—H5 | 0.9800 | C18—H18A | 0.9600 |
C6—C7 | 1.537 (3) | C18—H18B | 0.9600 |
C6—H6A | 0.9700 | C18—H18C | 0.9600 |
C6—H6B | 0.9700 | | |
| | | |
O1—C9—C1 | 108.65 (13) | C6—C7—H7B | 108.4 |
O1—C10—C11 | 110.75 (17) | C7—C6—H6A | 108.3 |
O1—C9—H9A | 110.0 | C7—C6—H6B | 108.3 |
O1—C9—H9B | 110.0 | C7—C8—C1 | 119.35 (14) |
O2—C12—O3 | 103.91 (12) | C7—C8—H8A | 107.5 |
O2—C2—C1 | 110.41 (12) | C7—C8—H8B | 107.5 |
O2—C2—C3 | 103.42 (12) | C8—C1—H1 | 107.6 |
O2—C12—C13 | 108.23 (15) | C8—C7—C6 | 115.59 (16) |
O2—C12—C14 | 111.91 (15) | C8—C7—H7A | 108.4 |
O2—C2—H2 | 106.9 | C8—C7—H7B | 108.4 |
O3—C3—C2 | 104.18 (12) | C9—C1—C2 | 109.27 (15) |
O3—C3—C4 | 109.76 (13) | C9—C1—C8 | 107.27 (14) |
O3—C12—C14 | 110.61 (16) | C9—C1—H1 | 107.6 |
O3—C12—C13 | 109.01 (15) | C10—O1—C9 | 116.31 (15) |
O3—C3—H3 | 107.5 | C10—C11—H11A | 109.5 |
O4—C4—C3 | 107.19 (12) | C10—C11—H11B | 109.5 |
O4—C4—C5 | 105.14 (12) | C10—C11—H11C | 109.5 |
O4—C4—H4 | 109.6 | C12—O2—C2 | 106.64 (11) |
O4—C15—C16 | 110.91 (17) | C12—C13—H13A | 109.5 |
O5—C5—C4 | 105.04 (13) | C12—C13—H13B | 109.5 |
O5—C5—C6 | 108.21 (14) | C12—C13—H13C | 109.5 |
O5—C5—H5 | 109.3 | C12—C14—H14A | 109.5 |
O5—C17—C18 | 112.14 (17) | C12—C14—H14B | 109.5 |
O6—C10—O1 | 123.8 (2) | C12—C14—H14C | 109.5 |
O6—C10—C11 | 125.41 (19) | C14—C12—C13 | 112.76 (16) |
O7—C15—O4 | 123.05 (18) | C15—O4—C4 | 118.14 (13) |
O7—C15—C16 | 126.01 (18) | C15—C16—H16A | 109.5 |
O8—C17—O5 | 123.50 (18) | C15—C16—H16B | 109.5 |
O8—C17—C18 | 124.35 (18) | C15—C16—H16C | 109.5 |
C1—C2—C3 | 121.43 (14) | C17—O5—C5 | 117.96 (14) |
C1—C2—H2 | 106.9 | C17—C18—H18A | 109.5 |
C1—C8—H8A | 107.5 | C17—C18—H18B | 109.5 |
C1—C8—H8B | 107.5 | C17—C18—H18C | 109.5 |
C1—C9—H9A | 110.0 | H6A—C6—H6B | 107.4 |
C1—C9—H9B | 110.0 | H7B—C7—H7A | 107.4 |
C2—C1—C8 | 117.15 (14) | H8A—C8—H8B | 107.0 |
C2—C1—H1 | 107.6 | H9A—C9—H9B | 108.3 |
C2—C3—H3 | 107.5 | H11A—C11—H11B | 109.5 |
C3—O3—C12 | 108.21 (12) | H11A—C11—H11C | 109.5 |
C3—C2—H2 | 106.9 | H11B—C11—H11C | 109.5 |
C3—C4—H4 | 109.6 | H13A—C13—H13B | 109.5 |
C4—C3—C2 | 119.77 (13) | H13A—C13—H13C | 109.5 |
C4—C5—C6 | 115.63 (14) | H13B—C13—H13C | 109.5 |
C4—C3—H3 | 107.5 | H14A—C14—H14B | 109.5 |
C4—C5—H5 | 109.3 | H14A—C14—H14C | 109.5 |
C5—C4—C3 | 115.60 (14) | H14B—C14—H14C | 109.5 |
C5—C6—C7 | 116.05 (16) | H16A—C16—H16B | 109.5 |
C5—C4—H4 | 109.6 | H16A—C16—H16C | 109.5 |
C5—C6—H6A | 108.3 | H16B—C16—H16C | 109.5 |
C5—C6—H6B | 108.3 | H18A—C18—H18B | 109.5 |
C6—C5—H5 | 109.3 | H18A—C18—H18C | 109.5 |
C6—C7—H7A | 108.4 | H18B—C18—H18C | 109.5 |
| | | |
O2—C2—C3—O3 | −8.55 (15) | C4—C5—C6—C7 | 50.7 (2) |
O2—C2—C3—C4 | 114.55 (15) | C5—O5—C17—O8 | −1.5 (3) |
O3—C3—C4—O4 | −82.64 (15) | C5—O5—C17—C18 | 178.17 (16) |
O3—C3—C4—C5 | 34.19 (18) | C5—C6—C7—C8 | −102.44 (19) |
O4—C4—C5—O5 | −63.89 (15) | C6—C7—C8—C1 | 71.9 (2) |
O4—C4—C5—C6 | 176.93 (13) | C8—C1—C2—O2 | −40.97 (19) |
O5—C5—C6—C7 | −66.71 (19) | C8—C1—C9—O1 | −167.84 (14) |
C1—C2—C3—O3 | −133.02 (14) | C8—C1—C2—C3 | 80.19 (19) |
C1—C2—C3—C4 | −9.9 (2) | C9—O1—C10—O6 | 4.6 (3) |
C2—O2—C12—O3 | −38.03 (16) | C9—O1—C10—C11 | −175.50 (16) |
C2—O2—C12—C14 | 81.35 (18) | C9—C1—C2—O2 | 81.22 (16) |
C2—O2—C12—C13 | −153.80 (15) | C9—C1—C2—C3 | −157.62 (14) |
C2—C1—C8—C7 | −72.5 (2) | C9—C1—C8—C7 | 164.33 (16) |
C2—C1—C9—O1 | 64.22 (17) | C10—O1—C9—C1 | −171.44 (15) |
C2—C3—C4—O4 | 157.01 (13) | C12—O2—C2—C1 | 159.91 (13) |
C2—C3—C4—C5 | −86.16 (18) | C12—O2—C2—C3 | 28.56 (15) |
C3—O3—C12—O2 | 32.26 (16) | C12—O3—C3—C2 | −14.29 (16) |
C3—O3—C12—C14 | −87.99 (17) | C12—O3—C3—C4 | −143.70 (13) |
C3—O3—C12—C13 | 147.48 (15) | C15—O4—C4—C3 | −98.44 (17) |
C3—C4—C5—O5 | 178.14 (12) | C15—O4—C4—C5 | 138.04 (15) |
C3—C4—C5—C6 | 58.95 (19) | C17—O5—C5—C4 | 132.15 (16) |
C4—O4—C15—O7 | 0.2 (3) | C17—O5—C5—C6 | −103.81 (18) |
C4—O4—C15—C16 | 178.18 (16) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O8i | 0.97 | 2.54 | 3.438 (3) | 154 |
Symmetry code: (i) x, −y+1/2, z+1/2. |
(III) (3aS,4
R,7S,9
R,9aS)-
7,9-diacetoxy-2,2-dimethylcyclooctano[
d][1,3]dioxan-4-ylmethyl acetate
top
Crystal data top
C18H28O8 | Z = 2 |
Mr = 372.40 | F(000) = 400 |
Triclinic, P1 | Dx = 1.270 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.7179 (16) Å | Cell parameters from 928 reflections |
b = 11.486 (2) Å | θ = 2.7–21.5° |
c = 11.720 (2) Å | µ = 0.10 mm−1 |
α = 76.515 (4)° | T = 291 K |
β = 74.547 (4)° | Block, colorless |
γ = 85.394 (4)° | 0.33 × 0.27 × 0.26 mm |
V = 973.6 (3) Å3 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 4173 independent reflections |
Radiation source: fine-focus sealed tube | 2082 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.080 |
ϕ and ω scans | θmax = 27.7°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→10 |
Tmin = 0.925, Tmax = 0.975 | k = −14→15 |
10725 measured reflections | l = −14→15 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.055 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 0.89 | w = 1/[σ2(Fo2) + (0.0581P)2] where P = (Fo2 + 2Fc2)/3 |
4173 reflections | (Δ/σ)max < 0.001 |
240 parameters | Δρmax = 0.22 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
Crystal data top
C18H28O8 | γ = 85.394 (4)° |
Mr = 372.40 | V = 973.6 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.7179 (16) Å | Mo Kα radiation |
b = 11.486 (2) Å | µ = 0.10 mm−1 |
c = 11.720 (2) Å | T = 291 K |
α = 76.515 (4)° | 0.33 × 0.27 × 0.26 mm |
β = 74.547 (4)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 4173 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2082 reflections with I > 2σ(I) |
Tmin = 0.925, Tmax = 0.975 | Rint = 0.080 |
10725 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 0.89 | Δρmax = 0.22 e Å−3 |
4173 reflections | Δρmin = −0.18 e Å−3 |
240 parameters | |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.4724 (2) | 0.31733 (17) | −0.14187 (14) | 0.0695 (5) | |
O2 | 0.4013 (2) | 0.21958 (14) | 0.25870 (13) | 0.0613 (5) | |
O3 | 0.55392 (19) | 0.07209 (14) | 0.35402 (13) | 0.0531 (4) | |
O4 | 0.88059 (19) | −0.03719 (13) | 0.24337 (13) | 0.0488 (4) | |
O5 | 0.9688 (2) | 0.37502 (14) | 0.20690 (15) | 0.0571 (5) | |
O6 | 0.2064 (3) | 0.3310 (2) | −0.17762 (19) | 0.1138 (9) | |
O7 | 1.1420 (2) | −0.01806 (15) | 0.10044 (15) | 0.0642 (5) | |
O8 | 0.8464 (3) | 0.3479 (2) | 0.40654 (18) | 0.0887 (7) | |
C1 | 0.5517 (3) | 0.2329 (2) | 0.04448 (18) | 0.0450 (6) | |
C2 | 0.4817 (3) | 0.1515 (2) | 0.16985 (19) | 0.0468 (6) | |
C3 | 0.6105 (3) | 0.06371 (19) | 0.23100 (18) | 0.0419 (5) | |
C4 | 0.8123 (3) | 0.07878 (18) | 0.18684 (19) | 0.0421 (5) | |
C5 | 0.8945 (3) | 0.17267 (19) | 0.2264 (2) | 0.0467 (6) | |
C6 | 0.8333 (3) | 0.30177 (19) | 0.19161 (19) | 0.0453 (6) | |
C7 | 0.8233 (3) | 0.3468 (2) | 0.0612 (2) | 0.0545 (6) | |
C8 | 0.6351 (3) | 0.3499 (2) | 0.0414 (2) | 0.0543 (6) | |
C9 | 0.3969 (3) | 0.2592 (2) | −0.01649 (19) | 0.0606 (7) | |
C10 | 0.3641 (4) | 0.3475 (2) | −0.2136 (2) | 0.0593 (7) | |
C11 | 0.4569 (4) | 0.4076 (3) | −0.3385 (2) | 0.0753 (8) | |
C12 | 0.3919 (3) | 0.1414 (2) | 0.3741 (2) | 0.0511 (6) | |
C13 | 0.3972 (4) | 0.2129 (3) | 0.4646 (2) | 0.0834 (10) | |
C14 | 0.2323 (3) | 0.0614 (3) | 0.4150 (2) | 0.0817 (9) | |
C15 | 1.0460 (3) | −0.0740 (2) | 0.1920 (2) | 0.0495 (6) | |
C16 | 1.0927 (3) | −0.1914 (2) | 0.2647 (2) | 0.0700 (8) | |
C17 | 0.9597 (4) | 0.3909 (2) | 0.3175 (3) | 0.0608 (7) | |
C18 | 1.1072 (4) | 0.4684 (2) | 0.3136 (3) | 0.0817 (9) | |
H1 | 0.6440 | 0.1875 | −0.0035 | 0.054* | |
H2 | 0.3866 | 0.1034 | 0.1638 | 0.056* | |
H3 | 0.5848 | −0.0173 | 0.2274 | 0.050* | |
H4 | 0.8500 | 0.0905 | 0.0983 | 0.051* | |
H5A | 1.0238 | 0.1688 | 0.1937 | 0.056* | |
H5B | 0.8714 | 0.1508 | 0.3141 | 0.056* | |
H6 | 0.7166 | 0.3148 | 0.2465 | 0.054* | |
H7A | 0.9004 | 0.2961 | 0.0122 | 0.065* | |
H7B | 0.8708 | 0.4270 | 0.0321 | 0.065* | |
H8A | 0.5544 | 0.3867 | 0.1025 | 0.065* | |
H8B | 0.6377 | 0.4027 | −0.0368 | 0.065* | |
H9A | 0.3398 | 0.1855 | −0.0117 | 0.073* | |
H9B | 0.3076 | 0.3112 | 0.0233 | 0.073* | |
H11A | 0.3753 | 0.4181 | −0.3894 | 0.113* | |
H11B | 0.5583 | 0.3594 | −0.3691 | 0.113* | |
H11C | 0.4973 | 0.4843 | −0.3381 | 0.113* | |
H13A | 0.5046 | 0.2591 | 0.4367 | 0.125* | |
H13B | 0.3963 | 0.1598 | 0.5413 | 0.125* | |
H13C | 0.2939 | 0.2658 | 0.4739 | 0.125* | |
H14A | 0.1238 | 0.1092 | 0.4269 | 0.123* | |
H14B | 0.2360 | 0.0066 | 0.4900 | 0.123* | |
H14C | 0.2349 | 0.0173 | 0.3544 | 0.123* | |
H16A | 1.0095 | −0.2506 | 0.2678 | 0.105* | |
H16B | 1.0862 | −0.1838 | 0.3456 | 0.105* | |
H16C | 1.2125 | −0.2156 | 0.2276 | 0.105* | |
H18A | 1.0983 | 0.4792 | 0.3938 | 0.123* | |
H18B | 1.0976 | 0.5449 | 0.2607 | 0.123* | |
H18C | 1.2211 | 0.4312 | 0.2838 | 0.123* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0469 (10) | 0.1120 (15) | 0.0398 (10) | −0.0031 (9) | −0.0184 (8) | 0.0114 (9) |
O2 | 0.0586 (10) | 0.0676 (11) | 0.0379 (9) | 0.0225 (9) | −0.0012 (8) | 0.0066 (8) |
O3 | 0.0411 (9) | 0.0721 (11) | 0.0360 (9) | 0.0117 (8) | −0.0082 (7) | 0.0021 (8) |
O4 | 0.0436 (9) | 0.0452 (9) | 0.0490 (9) | 0.0105 (7) | −0.0067 (7) | −0.0030 (7) |
O5 | 0.0568 (11) | 0.0540 (11) | 0.0604 (11) | −0.0121 (8) | −0.0172 (8) | −0.0061 (8) |
O6 | 0.0609 (14) | 0.199 (3) | 0.0696 (14) | −0.0107 (15) | −0.0287 (11) | 0.0102 (15) |
O7 | 0.0506 (10) | 0.0702 (12) | 0.0619 (12) | 0.0076 (9) | −0.0004 (9) | −0.0142 (10) |
O8 | 0.0923 (15) | 0.1126 (17) | 0.0636 (13) | −0.0180 (13) | −0.0116 (12) | −0.0284 (12) |
C1 | 0.0360 (12) | 0.0598 (16) | 0.0331 (12) | 0.0024 (11) | −0.0090 (10) | 0.0007 (11) |
C2 | 0.0390 (13) | 0.0578 (15) | 0.0404 (13) | −0.0020 (11) | −0.0144 (10) | 0.0005 (11) |
C3 | 0.0417 (13) | 0.0410 (13) | 0.0398 (13) | −0.0021 (10) | −0.0114 (10) | −0.0008 (10) |
C4 | 0.0420 (13) | 0.0408 (13) | 0.0373 (12) | 0.0060 (10) | −0.0103 (10) | 0.0014 (10) |
C5 | 0.0389 (13) | 0.0467 (14) | 0.0517 (14) | −0.0011 (11) | −0.0138 (11) | −0.0026 (11) |
C6 | 0.0406 (13) | 0.0448 (14) | 0.0468 (14) | −0.0066 (10) | −0.0097 (10) | −0.0027 (11) |
C7 | 0.0533 (15) | 0.0504 (15) | 0.0514 (15) | −0.0097 (12) | −0.0115 (12) | 0.0062 (12) |
C8 | 0.0549 (15) | 0.0545 (16) | 0.0443 (14) | 0.0039 (12) | −0.0143 (11) | 0.0074 (11) |
C9 | 0.0452 (14) | 0.086 (2) | 0.0405 (14) | −0.0034 (13) | −0.0134 (11) | 0.0091 (13) |
C10 | 0.0522 (16) | 0.0786 (19) | 0.0463 (15) | 0.0064 (14) | −0.0201 (13) | −0.0059 (13) |
C11 | 0.080 (2) | 0.100 (2) | 0.0435 (16) | 0.0007 (17) | −0.0249 (14) | −0.0008 (15) |
C12 | 0.0409 (13) | 0.0624 (16) | 0.0378 (13) | 0.0068 (12) | −0.0071 (10) | 0.0071 (12) |
C13 | 0.113 (3) | 0.079 (2) | 0.0426 (16) | 0.0028 (18) | −0.0004 (16) | −0.0080 (15) |
C14 | 0.0495 (16) | 0.126 (3) | 0.0546 (17) | −0.0235 (17) | −0.0115 (13) | 0.0154 (16) |
C15 | 0.0440 (14) | 0.0527 (15) | 0.0540 (16) | 0.0089 (12) | −0.0144 (12) | −0.0173 (13) |
C16 | 0.0662 (18) | 0.0572 (17) | 0.080 (2) | 0.0199 (14) | −0.0181 (15) | −0.0113 (15) |
C17 | 0.0662 (19) | 0.0533 (17) | 0.067 (2) | 0.0050 (14) | −0.0250 (15) | −0.0139 (15) |
C18 | 0.092 (2) | 0.0627 (19) | 0.108 (2) | −0.0067 (16) | −0.0510 (19) | −0.0221 (17) |
Geometric parameters (Å, º) top
O1—C10 | 1.310 (3) | C7—C8 | 1.528 (3) |
O1—C9 | 1.447 (2) | C7—H7A | 0.9700 |
O2—C12 | 1.426 (2) | C7—H7B | 0.9700 |
O2—C2 | 1.428 (3) | C8—H8A | 0.9700 |
O3—C3 | 1.415 (2) | C8—H8B | 0.9700 |
O3—C12 | 1.422 (3) | C9—H9A | 0.9700 |
O4—C15 | 1.339 (3) | C9—H9B | 0.9700 |
O4—C4 | 1.467 (2) | C10—C11 | 1.477 (3) |
O5—C17 | 1.333 (3) | C11—H11A | 0.9600 |
O5—C6 | 1.465 (3) | C11—H11B | 0.9600 |
O6—C10 | 1.193 (3) | C11—H11C | 0.9600 |
O7—C15 | 1.202 (3) | C12—C13 | 1.496 (3) |
O8—C17 | 1.200 (3) | C12—C14 | 1.501 (3) |
C1—C8 | 1.524 (3) | C13—H13A | 0.9600 |
C1—C9 | 1.525 (3) | C13—H13B | 0.9600 |
C1—C2 | 1.531 (3) | C13—H13C | 0.9600 |
C1—H1 | 0.9800 | C14—H14A | 0.9600 |
C2—C3 | 1.549 (3) | C14—H14B | 0.9600 |
C2—H2 | 0.9800 | C14—H14C | 0.9600 |
C3—C4 | 1.515 (3) | C15—C16 | 1.492 (3) |
C3—H3 | 0.9800 | C16—H16A | 0.9600 |
C4—C5 | 1.510 (3) | C16—H16B | 0.9600 |
C4—H4 | 0.9800 | C16—H16C | 0.9600 |
C5—C6 | 1.516 (3) | C17—C18 | 1.486 (4) |
C5—H5A | 0.9700 | C18—H18A | 0.9600 |
C5—H5B | 0.9700 | C18—H18B | 0.9600 |
C6—C7 | 1.516 (3) | C18—H18C | 0.9600 |
C6—H6 | 0.9800 | | |
| | | |
O1—C9—C1 | 107.10 (17) | C6—C7—C8 | 115.03 (18) |
O1—C10—C11 | 113.0 (2) | C6—C7—H7A | 108.5 |
O1—C9—H9A | 110.3 | C6—C7—H7B | 108.5 |
O1—C9—H9B | 110.3 | C7—C6—H6 | 109.5 |
O2—C2—C1 | 111.31 (18) | C7—C8—H8A | 107.5 |
O2—C2—C3 | 103.14 (16) | C7—C8—H8B | 107.5 |
O2—C2—H2 | 107.0 | C8—C1—C2 | 116.44 (19) |
O2—C12—C13 | 109.7 (2) | C8—C1—C9 | 109.8 (2) |
O2—C12—C14 | 112.3 (2) | C8—C1—H1 | 107.5 |
O3—C3—C2 | 103.74 (16) | C8—C7—H7A | 108.5 |
O3—C3—C4 | 109.03 (17) | C8—C7—H7B | 108.5 |
O3—C3—H3 | 107.5 | C9—C1—C2 | 107.85 (17) |
O3—C12—O2 | 103.51 (16) | C9—C1—H1 | 107.5 |
O3—C12—C13 | 108.2 (2) | C10—O1—C9 | 118.31 (18) |
O3—C12—C14 | 110.2 (2) | C10—C11—H11A | 109.5 |
O4—C4—C3 | 102.42 (15) | C10—C11—H11B | 109.5 |
O4—C4—C5 | 106.16 (17) | C10—C11—H11C | 109.5 |
O4—C4—H4 | 109.9 | C12—O2—C2 | 106.45 (16) |
O4—C15—C16 | 110.6 (2) | C12—C13—H13A | 109.5 |
O5—C6—C5 | 106.17 (17) | C12—C13—H13B | 109.5 |
O5—C6—C7 | 105.38 (16) | C12—C13—H13C | 109.5 |
O5—C6—H6 | 109.5 | C12—C14—H14A | 109.5 |
O5—C17—C18 | 110.6 (3) | C12—C14—H14B | 109.5 |
O6—C10—O1 | 121.9 (2) | C12—C14—H14C | 109.5 |
O6—C10—C11 | 125.0 (2) | C13—C12—C14 | 112.5 (2) |
O7—C15—O4 | 123.7 (2) | C15—O4—C4 | 118.76 (17) |
O7—C15—C16 | 125.7 (2) | C15—C16—H16A | 109.5 |
O8—C17—O5 | 123.7 (3) | C15—C16—H16B | 109.5 |
O8—C17—C18 | 125.7 (3) | C15—C16—H16C | 109.5 |
C1—C2—C3 | 120.74 (17) | C17—O5—C6 | 118.87 (19) |
C1—C8—C7 | 119.1 (2) | C17—C18—H18A | 109.5 |
C1—C2—H2 | 107.0 | C17—C18—H18B | 109.5 |
C1—C8—H8A | 107.5 | C17—C18—H18C | 109.5 |
C1—C9—H9A | 110.3 | H5A—C5—H5B | 107.1 |
C1—C9—H9B | 110.3 | H7A—C7—H7B | 107.5 |
C1—C8—H8B | 107.5 | H8A—C8—H8B | 107.0 |
C2—C1—H1 | 107.5 | H9A—C9—H9B | 108.6 |
C2—C3—H3 | 107.5 | H11A—C11—H11B | 109.5 |
C3—O3—C12 | 110.06 (15) | H11A—C11—H11C | 109.5 |
C3—C2—H2 | 107.0 | H11B—C11—H11C | 109.5 |
C3—C4—H4 | 109.9 | H13A—C13—H13B | 109.5 |
C4—C3—C2 | 120.79 (17) | H13A—C13—H13C | 109.5 |
C4—C3—H3 | 107.5 | H13B—C13—H13C | 109.5 |
C4—C5—C6 | 118.00 (18) | H14A—C14—H14B | 109.5 |
C4—C5—H5A | 107.8 | H14A—C14—H14C | 109.5 |
C4—C5—H5B | 107.8 | H14B—C14—H14C | 109.5 |
C5—C4—C3 | 117.95 (18) | H16A—C16—H16B | 109.5 |
C5—C4—H4 | 109.9 | H16A—C16—H16C | 109.5 |
C5—C6—C7 | 116.38 (19) | H16B—C16—H16C | 109.5 |
C5—C6—H6 | 109.5 | H18A—C18—H18B | 109.5 |
C6—C5—H5A | 107.8 | H18A—C18—H18C | 109.5 |
C6—C5—H5B | 107.8 | H18B—C18—H18C | 109.5 |
| | | |
O2—C2—C3—O3 | 14.3 (2) | C4—C5—C6—C7 | −46.1 (3) |
O2—C2—C3—C4 | −108.1 (2) | C5—C6—C7—C8 | 100.1 (2) |
O3—C3—C4—O4 | 75.32 (19) | C6—O5—C17—O8 | 0.3 (4) |
O3—C3—C4—C5 | −40.7 (2) | C6—O5—C17—C18 | −179.44 (19) |
O4—C4—C5—C6 | −174.07 (17) | C6—C7—C8—C1 | −75.8 (3) |
O5—C6—C7—C8 | −142.6 (2) | C8—C1—C2—O2 | 37.3 (3) |
C1—C2—C3—O3 | 139.3 (2) | C8—C1—C9—O1 | 62.4 (2) |
C1—C2—C3—C4 | 16.8 (3) | C8—C1—C2—C3 | −83.7 (3) |
C2—O2—C12—O3 | 37.1 (2) | C9—O1—C10—O6 | 1.9 (4) |
C2—O2—C12—C13 | 152.4 (2) | C9—O1—C10—C11 | 179.1 (2) |
C2—O2—C12—C14 | −81.7 (2) | C9—C1—C2—O2 | −86.6 (2) |
C2—C1—C8—C7 | 75.4 (3) | C9—C1—C2—C3 | 152.4 (2) |
C2—C1—C9—O1 | −169.73 (19) | C9—C1—C8—C7 | −161.68 (18) |
C2—C3—C4—O4 | −164.81 (18) | C10—O1—C9—C1 | 179.1 (2) |
C2—C3—C4—C5 | 79.1 (3) | C12—O3—C3—C4 | 138.10 (18) |
C3—O3—C12—O2 | −27.7 (2) | C12—O3—C3—C2 | 8.2 (2) |
C3—O3—C12—C13 | −144.03 (19) | C12—O2—C2—C1 | −162.57 (17) |
C3—O3—C12—C14 | 92.6 (2) | C12—O2—C2—C3 | −31.7 (2) |
C3—C4—C5—C6 | −60.0 (3) | C15—O4—C4—C3 | 155.64 (18) |
C4—O4—C15—O7 | −1.1 (3) | C15—O4—C4—C5 | −80.1 (2) |
C4—O4—C15—C16 | 178.2 (2) | C17—O5—C6—C5 | −82.0 (2) |
C4—C5—C6—O5 | −163.02 (17) | C17—O5—C6—C7 | 154.0 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16A···O6i | 0.96 | 2.53 | 3.399 (3) | 151 |
Symmetry code: (i) −x+1, −y, −z. |
Experimental details
| (I) | (II) | (III) |
Crystal data |
Chemical formula | C17H26O8 | C18H28O8 | C18H28O8 |
Mr | 358.38 | 372.40 | 372.40 |
Crystal system, space group | Triclinic, P1 | Orthorhombic, Pccn | Triclinic, P1 |
Temperature (K) | 291 | 291 | 291 |
a, b, c (Å) | 9.1632 (9), 9.2131 (9), 11.5904 (11) | 19.206 (12), 26.611 (17), 7.748 (5) | 7.7179 (16), 11.486 (2), 11.720 (2) |
α, β, γ (°) | 94.709 (2), 92.486 (2), 102.912 (2) | 90, 90, 90 | 76.515 (4), 74.547 (4), 85.394 (4) |
V (Å3) | 948.60 (16) | 3960 (4) | 973.6 (3) |
Z | 2 | 8 | 2 |
Radiation type | Mo Kα | Mo Kα | Mo Kα |
µ (mm−1) | 0.10 | 0.10 | 0.10 |
Crystal size (mm) | 0.35 × 0.31 × 0.28 | 0.49 × 0.40 × 0.39 | 0.33 × 0.27 × 0.26 |
|
Data collection |
Diffractometer | Bruker SMART CCD area-detector diffractometer | Bruker SMART CCD area-detector diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) | Multi-scan (SADABS; Sheldrick, 1996) | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.936, 0.973 | 0.905, 0.963 | 0.925, 0.975 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9524, 3500, 2880 | 24680, 3822, 2811 | 10725, 4173, 2082 |
Rint | 0.019 | 0.053 | 0.080 |
(sin θ/λ)max (Å−1) | 0.605 | 0.617 | 0.654 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.136, 1.06 | 0.042, 0.111, 1.04 | 0.055, 0.132, 0.89 |
No. of reflections | 3500 | 3822 | 4173 |
No. of parameters | 230 | 241 | 240 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.32, −0.25 | 0.20, −0.14 | 0.22, −0.18 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···O6i | 0.96 | 2.53 | 3.439 (3) | 158 |
Symmetry code: (i) −x+1, −y, −z+2. |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O8i | 0.97 | 2.54 | 3.438 (3) | 154 |
Symmetry code: (i) x, −y+1/2, z+1/2. |
Hydrogen-bond geometry (Å, º) for (III) top
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16A···O6i | 0.96 | 2.53 | 3.399 (3) | 151 |
Symmetry code: (i) −x+1, −y, −z. |
Details of the synthesis of the three cyclooctitol derivatives (I)–(III) have been reported previously (Mehta & Pallavi, 2002). The synthetic scheme provided, through moderate regio- and stereocontrol, a convenient access to cyclooctitols – an emerging class of medium ring glycomimics which have been projected to provide better adaptability at the active site of a glycosidase enzyme than cyclohexitols and cyclopentitols (Wang et al., 2000; Paquette & Zhang, 2006). Though interesting in their own right, studies into the solid-state supramolecular assemblies of cyclooctitols or their derivatives have been rarely reported in the literature (Salamci et al., 2006; Kawazoe et al., 2001; Andriuzzi et al., 2005; Wang et al., 2001). We report here details of the conformations of the eight-membered carbocyclic rings in the crystal structures of the three cyclooctitol derivatives (I)–(III) and examine how these molecules pack in the solid state. Preliminary details of the structures of (II) and (III) in CIF form were a minor part of the Mehta & Pallavi (2002) publication.
In the monocyclic cyclooctane tetraacetate (I) (Fig. 1), the puckering parameters (Cremer & Pople, 1975) of the cyclooctane ring [q2 = 1.0294 (18) Å, q3 = 0.5718 (19) Å, q4 = -0.3209 (19) Å, ϕ2 = 5.05 (10)°, ϕ3 = 180.00 (19)° and QT = 1.2206 (19) Å] are in conformity with those of the boat–chair (BC) form (Evans & Boeyens, 1988; Allen et al., 1996), which is the predominant conformer of the cyclooctane molecule as revealed through gas-phase electron diffraction analysis at 300 K and an NMR study in solution at 161.5 K (Rocha et al., 1998). The crystal packing of (I) is realised mainly through van der Waals interactions. The shortest intermolecular contact is between a poorly resolved methyl hydrogen H13A and an adjacent inversion-related carbonyl O atom (O6; Table 1), giving rise to potential dimers [graph-set motif R22(8); Bernstein et al., 1995], as shown in Fig. 2(a). As methyl H atoms are not noted for their acidity and the H-atom positions are not well defined in this room- temperature structure determination, this may be an adventitious contact. Such a motif, though very similar to the archetypical carboxylic acid dimer synthon (Fig. 2b), is not commonly encountered. A Cambridge Structural Database search (CSD; Version 5.28 of November 2006; Allen, 2002) for the centrosymmetric R22(8) C—H···O motif (as shown in Fig. 2a) in organic molecules, whose crystal structures were refined to R < 0.1, with low-temperature data and correctly oriented methyl H atoms, only generated eight hits.
Owing to its fusion with the 1,3-dioxolane ring, the eight-membered ring in bicyclic cyclooctitol triacetate (II) (Fig. 3) distorts slightly from the expected BC conformation, as revealed by its puckering parameters [q2 = 0.8958 (17) Å, q3 = 0.6673 (17) Å, q4 = -0.3004 (17) Å, ϕ2 = 258.18 (11)°, ϕ3 = 123.87 (14)° and QT = 1.1567 (17) Å]. The puckering parameters of the five-membered 1,3-dioxolane ring [q2 = 0.3380 (15) Å and ϕ2 = 158.2 (3)°] best describe a half-chair (T) conformation, twisted at the C12—O2 bond (Cremer & Pople, 1975). As with (I) the crystal packing of (II) involves mainly van der Waals interactions; the shortest contact is between methylene atom H6B (on C6) and carbonyl atom O8 of an adjacent glide-related molecule (Table 2), and gives rise to chains extending along c as shown in Fig. 4.
In the bicyclic cyclooctitol triacetate (III) (Fig. 5), a regioisomer of (II), the eight-membered ring distorts slightly, as with (II), through its fusion with the 1,3-dioxolane ring, from the expected BC conformation [puckering parameters q2 = 0.845 (2) Å, q3 = 0.657 (2) Å, q4 = -0.321 (2) Å, ϕ2 = 81.50 (16)°, ϕ3 = 306.9 (2)° and QT = 1.118 (2) Å]. As in (II), the puckering parameters of the five-membered 1,3-dioxolane ring in (III) [q2 = 0.330 (2) Å and ϕ2 = 348.8 (4)°] best describe a half-chair (T) conformation, twisted at the C12—O2 bond. As with (I), the packing is realised mainly through van der Waals interactions; the shortest intermolecular contact is between the poorly resolved methyl atom H16A and an adjacent inversion-related carbonyl atom O6 (Table 3) at (1 - x, -y, -z), which would give rise to dimers with graph-set motif R22(24) involving the transannular acetate groups at atoms C1 and C4.
To summarize, the present study reports on the conformations and packing of three cyclooctitol acetates. Two types of packing interactions are observed; centrosymmetric dimers and glide-related chains.