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The title compound, (1R)-4,7,7-tri­methyl-3-oxobi­cyclo­[2.2.1]­heptane-2-endo-acetic acid, C12H18O3, like its lower homolog, forms carboxyl-to-ketone hydrogen-bonding catemers (Z′ = 2) [O...O = 2.729 (5) and 2.707 (5) Å, and O—H...O = 165 and 170°] with screw-related components. The two mol­ecules of the asymmetric unit differ slightly in conformation and produce two counter-aligned hydrogen-bonding chains, both aligned with the b axis. Close intermolecular C—H...O=C contacts exist for the ketone group of one mol­ecule and for both the ketone and carboxyl functions in the other.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010401947X/fr1504sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010401947X/fr1504Isup2.hkl
Contains datablock I

CCDC reference: 254928

Comment top

Simple crystalline carboxylic acids typically aggregate as hydrogen-bonding dimers, a pattern that often changes when other hydrogen-bonding functionalities are present. In our X-ray study of the five known hydrogen-bonding motifs for keto acids, we have found that carboxyl pairing is inhibited whenever centrosymmetry is thwarted (Lalancette & Thompson, 2003) or molecular flexibility is severely curtailed (Lalancette Brunskill & Thompson, 1999; Barcon et al., 2002). Hence, our attention has often centered on single enantiomers and on cyclic systems. The title compound, (I), incorporates both these restraints, and the observed hydrogen-bonding involves carboxyl-to-ketone chains (catemers). \sch

The category of γ-keto acids to which (I) belongs is rich in hydrogen-bonding types, embracing dimers, internal hydrogen bonds, and catemers of the screw, translational and glide types. In the lower homolog of (I), camphorcarboxylic acid (Lalancette et al., 1991), both the enantiomeric and racemic forms exhibit the catemeric hydrogen-bonding arrangement. The relationship of camphorcarboxylic acid to (I) is of interest, because we have found racemic cases in which homologation by a single CH2 unit suffices to shift the hydrogen-bonding pattern from catemer to dimer (Lalancette Brunskill & Thompson, 1999; Barcon et al., 2002). This is believed to reflect the expanded repertoire of centrosymmetric dimerization patterns of low energy that results from greater molecular flexibility. However, in nonracemates, this flexibility is typically overridden by the unavailability of centrosymmetric modes (Coté et al., 1997; Lalancette Thompson & Brunskill, 1999).

Fig. 1 presents a view of the asymmetric unit of (I) with the atom-numbering scheme. Compound (I) is skeletally rigid except for rotation about the C2—C11 and C11—C12 bonds, and the two molecules differ almost solely in slight rotations about these two bonds. Both molecules adopt a C2—C11-staggered conformation, with the carboxyl aimed away from the ketone. In molecule (IA), the C3A—C2A—C11A—C12A torsion angle is −167.6 (4)°, while in (IB) this angle is −171.9 (4)°. The carboxyl group is rotated so that the O3—C12—C11—C2 torsion angles are 23.7 (7) and 21.3 (7)° in (IA) and (IB), respectively. The resulting dihedral angle between the carboxyl and ketone planes (O2—C12—O3 versus C2—C3—C4—O1) is 80.1 (2)° in the case of (IA) and 75.9 (2)° for (IB).

The partial averaging of C—O bond lengths and C—C—O angles by disorder often found in acids is seen only in the dimeric hydrogen-bonding mode, the geometry of which allows transposition of the two carboxyl O atoms. As in other catemers, no significant averaging is observed for the carboxyl groups of (IA) and (IB). The bond lengths for (IA) are 1.190 (6) and 1.304 (6) Å, with angles of 124.4 (5) and 113.0 (5)°, while for (IB) these lengths are 1.171 (5) and 1.326 (6) Å, with angles of 123.7 (5) and 111.7 (5)°. 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 staggered relative to the substituents at their points of attachment.

Fig. 2 shows a packing diagram for the cell of (I). Each molecule in the asymmetric unit aggregates with its own type to generate the two single-strand hydrogen-bonding catemers illustrated by the inclusion of extracellular molecules. Both of these independent counterdirectional chains follow screw axes parallel to b.

We characterize the geometry of hydrogen bonding to carbonyls using a combination of the H···OC angle and the H···OC—C torsion angle. These describe the approach of the H atom to the O in terms of its deviation from, respectively, CO axiality (ideal 120°) and planarity with the carbonyl (ideal 0°). For (IA), these angles are H···OC 136.0 and H···OC—C −14.9°. For the (IB) catemers, the corresponding values are 133.2 and −23.6°, respectively.

Three close C—H···OC contacts exist for the ketone and carboxyl functions. The ketone in (IA) has a contact to atom H5B in a translationally related neighbor (2.58 Å), and the ketone in (IB) has a corresponding translational contact to atom H5C of 2.63 Å. The carboxyl carbonyl (CO2B) has a 2.64 Å contact to atom H6A in a screw-related neighbor. These distances all lie within the 2.7 Å range we normally employ for non-bonded H···O packing interactions (Steiner, 1997). Using compiled data for a large number of C—H···O contacts, Steiner & Desiraju (1998) find significant statistical directionality even as far out as 3.0 Å, and conclude that these are legitimately viewed as `weak hydrogen bonds', with a greater contribution to packing forces than simple van der Waals attractions.

The solid-state (KBr) IR spectrum of (I) has broad CO absorption with maxima at 1736 and 1711 cm−1, essentially identical to those for camphorcarboxylic acid (Lalancette et al., 1991). These peaks are consistent with hydrogen-bonding shifts due, respectively, to its removal from COOH and its addition to a strained ketone. In CHCl3, where dimers predominate, the absorptions appear, presumably reversed, at 1738 and 1712 cm−1.

Experimental top

Compound (I) was prepared by Jones oxidation of (-)-(1R)-2-endo-3-exo-isoborneolacetic acid, purchased from Aldrich Chemical Co., Milwaukee, Wisconsin, USA. Recrystallization from 1:1 cyclohexane-ethyl ether provided crystals of (I) suitable for X-ray analysis (m.p. 358 K). The positive rotation of the (1R)-enantiomer of (I) has been established (Rupe & Häfliger, 1940).

Refinement top

All H atoms for (I) were found in electron-density difference maps but were placed in calculated positions, with C—H = 0.97 for methylene H, 0.98 for methine H and 0.96 Å for methyl H, and O—H = 0.82 Å for carboxyl H, and allowed to refine as riding models on their respective C and O atoms, with Uiso(H) = 1.5Ueq(O,Cmethyl) and 1.2Ueq(C) for the rest.

Computing details top

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.

Figures top
[Figure 1] Fig. 1. A view of the asymmetric unit of (I), with numbering shown for (IA); the second molecule in the asymmetric unit, (IB), is numbered identically. Displacement ellipsoids are set at the 20% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. A packing diagram for (I), with extracellular molecules, showing the two counterdirectional acid-to-ketone catemers. Heavy bonds denote (IA) and open bonds are used for (IB). For clarity, all C-bound H atoms have been omitted. Displacement ellipsoids are set at the 20% probability level.
(1R)-4,7,7-trimethyl-3-oxobicyclo[2.2.1]heptane-2-endo-acetic acid top
Crystal data top
C12H18O3F(000) = 456
Mr = 210.26Dx = 1.210 Mg m3
Monoclinic, P21Melting point: 358 K
Hall symbol: P 2ybMo Kα radiation, λ = 0.71073 Å
a = 6.6423 (10) ÅCell parameters from 25 reflections
b = 14.734 (3) Åθ = 6.0–13.2°
c = 11.817 (2) ŵ = 0.09 mm1
β = 93.756 (13)°T = 296 K
V = 1154.0 (4) Å3Tablet, colorless
Z = 40.38 × 0.30 × 0.18 mm
Data collection top
Siemens P4
diffractometer
1161 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.077
Graphite monochromatorθmax = 25.0°, θmin = 2.2°
2θ/θ scansh = 77
Absorption correction: numerical
(SHELXTL; Sheldrick, 1997)
k = 1717
Tmin = 0.972, Tmax = 0.986l = 1414
4574 measured reflections3 standard reflections every 97 reflections
2110 independent reflections intensity decay: variation <2.0%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.096H-atom parameters constrained
S = 0.99 w = 1/[σ2(Fo2) + (0.006P)2]
where P = (Fo2 + 2Fc2)/3
2110 reflections(Δ/σ)max < 0.001
271 parametersΔρmax = 0.16 e Å3
1 restraintΔρmin = 0.16 e Å3
Crystal data top
C12H18O3V = 1154.0 (4) Å3
Mr = 210.26Z = 4
Monoclinic, P21Mo Kα radiation
a = 6.6423 (10) ŵ = 0.09 mm1
b = 14.734 (3) ÅT = 296 K
c = 11.817 (2) Å0.38 × 0.30 × 0.18 mm
β = 93.756 (13)°
Data collection top
Siemens P4
diffractometer
1161 reflections with I > 2σ(I)
Absorption correction: numerical
(SHELXTL; Sheldrick, 1997)
Rint = 0.077
Tmin = 0.972, Tmax = 0.9863 standard reflections every 97 reflections
4574 measured reflections intensity decay: variation <2.0%
2110 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0491 restraint
wR(F2) = 0.096H-atom parameters constrained
S = 0.99Δρmax = 0.16 e Å3
2110 reflectionsΔρmin = 0.16 e Å3
271 parameters
Special details top

Experimental. crystal mounted on glass fiber using cyanoacrylate cement

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
xyzUiso*/Ueq
O1A0.9351 (6)0.2404 (2)0.0072 (3)0.0568 (11)
O1B0.5695 (6)0.2151 (2)0.4699 (3)0.0532 (10)
C1B0.8954 (8)0.0387 (4)0.5688 (4)0.0476 (14)
H1B0.90180.02100.60530.057*
C1A0.5993 (8)0.4175 (3)0.0558 (4)0.0511 (15)
H1A0.59070.48010.08330.061*
O2A0.8965 (8)0.5708 (3)0.1945 (4)0.1067 (17)
O2B0.5550 (6)0.1271 (2)0.3241 (3)0.0745 (13)
C2B0.6849 (8)0.0623 (3)0.5135 (4)0.0432 (14)
H2B0.58530.04830.56860.052*
C2A0.8032 (8)0.3932 (3)0.0117 (4)0.0403 (13)
H2A0.90780.41450.06780.048*
O3A0.9693 (7)0.5607 (2)0.0116 (3)0.0721 (13)
H3A0.99260.61500.01860.108*
O3B0.5233 (7)0.1072 (2)0.5075 (3)0.0663 (11)
H3B0.49680.16160.50640.100*
C3B0.7053 (8)0.1667 (3)0.5077 (4)0.0369 (13)
C3A0.7987 (8)0.2906 (3)0.0189 (4)0.0409 (13)
C4B0.9072 (8)0.1920 (4)0.5562 (5)0.0494 (14)
C4A0.6015 (8)0.2641 (3)0.0642 (5)0.0493 (14)
C5B1.0477 (9)0.1563 (4)0.4664 (6)0.0724 (19)
H5C1.18260.18090.47970.087*
H5D0.99590.17290.39060.087*
C5A0.4484 (9)0.2910 (5)0.0338 (5)0.074 (2)
H5A0.49250.26920.10560.089*
H5B0.31690.26520.02230.089*
C6B1.0494 (9)0.0513 (4)0.4811 (6)0.0637 (17)
H6C1.00850.02070.41070.076*
H6D1.18150.02950.50870.076*
C6A0.4378 (8)0.3929 (5)0.0338 (5)0.0605 (16)
H6A0.46670.41780.10700.073*
H6B0.30650.41410.01380.073*
C7B0.9361 (8)0.1173 (4)0.6511 (4)0.0538 (14)
C7A0.5744 (7)0.3440 (4)0.1493 (4)0.0488 (13)
C8B0.7803 (9)0.1285 (4)0.7417 (4)0.0778 (19)
H8D0.80160.08220.79840.117*
H8E0.64650.12300.70640.117*
H8F0.79590.18710.77650.117*
C8A0.7396 (8)0.3467 (4)0.2462 (4)0.0663 (16)
H8A0.71570.39690.29540.099*
H8B0.86880.35380.21540.099*
H8C0.73770.29110.28850.099*
C9B1.1458 (9)0.1176 (5)0.7142 (6)0.091 (2)
H9D1.15260.07050.77030.136*
H9E1.16910.17530.75040.136*
H9F1.24680.10730.66110.136*
C9A0.3731 (8)0.3455 (4)0.2003 (5)0.0783 (19)
H9A0.36760.39610.25120.117*
H9B0.35520.29010.24140.117*
H9C0.26780.35110.14110.117*
C10A0.5894 (10)0.1686 (4)0.1092 (6)0.090 (2)
H10A0.60830.12630.04910.134*
H10B0.45950.15910.13830.134*
H10C0.69280.15980.16880.134*
C10B0.9351 (9)0.2898 (4)0.5882 (6)0.085 (2)
H10D0.91210.32710.52200.127*
H10E1.07010.29910.62020.127*
H10F0.84080.30590.64310.127*
C11B0.6116 (8)0.0204 (3)0.4011 (4)0.0483 (15)
H11C0.71480.02930.34780.058*
H11D0.49250.05320.37210.058*
C11A0.8593 (8)0.4269 (3)0.1043 (4)0.0503 (14)
H11A0.97460.39240.12670.060*
H11B0.74770.41440.15920.060*
C12B0.5604 (8)0.0800 (4)0.4039 (4)0.0461 (13)
C12A0.9097 (9)0.5266 (4)0.1100 (5)0.0570 (16)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O1A0.059 (3)0.036 (2)0.078 (3)0.0076 (19)0.020 (2)0.0014 (19)
O1B0.054 (2)0.042 (2)0.063 (2)0.0071 (19)0.001 (2)0.0022 (18)
C1B0.063 (4)0.032 (3)0.048 (3)0.002 (3)0.007 (3)0.006 (3)
C1A0.065 (4)0.038 (3)0.051 (3)0.016 (3)0.008 (3)0.000 (3)
O2A0.191 (5)0.074 (3)0.056 (2)0.019 (3)0.018 (3)0.017 (2)
O2B0.122 (4)0.050 (3)0.052 (2)0.016 (2)0.008 (2)0.018 (2)
C2B0.057 (4)0.033 (3)0.040 (3)0.000 (3)0.009 (3)0.001 (2)
C2A0.045 (3)0.032 (3)0.044 (3)0.001 (3)0.003 (3)0.002 (2)
O3A0.116 (4)0.036 (2)0.064 (2)0.021 (3)0.009 (2)0.005 (2)
O3B0.112 (3)0.036 (2)0.053 (2)0.030 (2)0.018 (2)0.0053 (19)
C3B0.036 (3)0.032 (3)0.043 (3)0.010 (3)0.004 (3)0.001 (2)
C3A0.046 (4)0.030 (3)0.047 (3)0.008 (3)0.004 (3)0.007 (2)
C4B0.035 (3)0.038 (3)0.074 (4)0.003 (3)0.003 (3)0.004 (3)
C4A0.038 (3)0.034 (3)0.076 (4)0.007 (2)0.006 (3)0.013 (3)
C5B0.054 (4)0.074 (5)0.091 (5)0.006 (4)0.014 (4)0.010 (4)
C5A0.052 (4)0.097 (6)0.073 (4)0.020 (4)0.010 (4)0.020 (4)
C6B0.055 (4)0.056 (4)0.080 (4)0.017 (3)0.009 (3)0.001 (3)
C6A0.041 (4)0.079 (5)0.061 (4)0.018 (3)0.003 (3)0.003 (3)
C7B0.054 (3)0.046 (3)0.060 (3)0.003 (3)0.004 (3)0.005 (3)
C7A0.047 (3)0.049 (3)0.051 (3)0.001 (3)0.007 (3)0.005 (3)
C8B0.111 (5)0.074 (4)0.049 (3)0.009 (4)0.011 (3)0.006 (3)
C8A0.078 (4)0.073 (4)0.048 (3)0.002 (4)0.004 (3)0.016 (3)
C9B0.083 (5)0.080 (5)0.106 (5)0.012 (4)0.024 (4)0.002 (4)
C9A0.071 (4)0.088 (5)0.079 (4)0.016 (4)0.029 (3)0.005 (4)
C10A0.102 (6)0.044 (4)0.128 (5)0.025 (4)0.053 (5)0.009 (4)
C10B0.069 (5)0.049 (4)0.134 (6)0.018 (4)0.012 (4)0.016 (4)
C11B0.070 (4)0.032 (3)0.043 (3)0.002 (3)0.006 (3)0.005 (2)
C11A0.060 (4)0.044 (3)0.047 (3)0.002 (3)0.005 (3)0.000 (3)
C12B0.050 (3)0.042 (3)0.046 (3)0.001 (3)0.002 (3)0.008 (3)
C12A0.076 (4)0.056 (4)0.040 (3)0.001 (3)0.007 (3)0.005 (3)
Geometric parameters (Å, º) top
O1A—C3A1.224 (6)C5A—H5A0.9700
O1B—C3B1.213 (5)C5A—H5B0.9700
C1B—C6B1.514 (7)C6B—H6C0.9700
C1B—C7B1.526 (7)C6B—H6D0.9700
C1B—C2B1.544 (7)C6A—H6A0.9700
C1B—H1B0.9800C6A—H6B0.9700
C1A—C6A1.501 (7)C7B—C9B1.536 (7)
C1A—C2A1.526 (7)C7B—C8B1.546 (7)
C1A—C7A1.564 (7)C7A—C9A1.503 (6)
C1A—H1A0.9800C7A—C8A1.533 (7)
O2A—C12A1.190 (6)C8B—H8D0.9600
O2B—C12B1.171 (5)C8B—H8E0.9600
C2B—C11B1.516 (6)C8B—H8F0.9600
C2B—C3B1.546 (6)C8A—H8A0.9600
C2B—H2B0.9800C8A—H8B0.9600
C2A—C3A1.514 (6)C8A—H8C0.9600
C2A—C11A1.528 (6)C9B—H9D0.9600
C2A—H2A0.9800C9B—H9E0.9600
O3A—C12A1.304 (6)C9B—H9F0.9600
O3A—H3A0.8200C9A—H9A0.9600
O3B—C12B1.326 (6)C9A—H9B0.9600
O3B—H3B0.8200C9A—H9C0.9600
C3B—C4B1.472 (7)C10A—H10A0.9600
C3A—C4A1.499 (7)C10A—H10B0.9600
C4B—C10B1.498 (8)C10A—H10C0.9600
C4B—C5B1.550 (8)C10B—H10D0.9600
C4B—C7B1.574 (8)C10B—H10E0.9600
C4A—C10A1.508 (7)C10B—H10F0.9600
C4A—C5A1.542 (8)C11B—C12B1.519 (7)
C4A—C7A1.567 (7)C11B—H11C0.9700
C5B—C6B1.557 (9)C11B—H11D0.9700
C5B—H5C0.9700C11A—C12A1.510 (8)
C5B—H5D0.9700C11A—H11A0.9700
C5A—C6A1.504 (9)C11A—H11B0.9700
C6B—C1B—C7B104.1 (5)H6A—C6A—H6B109.2
C6B—C1B—C2B108.5 (4)C1B—C7B—C9B115.4 (5)
C7B—C1B—C2B102.5 (4)C1B—C7B—C8B115.1 (5)
C6B—C1B—H1B113.6C9B—C7B—C8B106.9 (4)
C7B—C1B—H1B113.6C1B—C7B—C4B93.9 (3)
C2B—C1B—H1B113.6C9B—C7B—C4B114.1 (5)
C6A—C1A—C2A108.2 (4)C8B—C7B—C4B111.3 (4)
C6A—C1A—C7A103.2 (4)C9A—C7A—C8A108.2 (4)
C2A—C1A—C7A102.4 (4)C9A—C7A—C1A114.3 (4)
C6A—C1A—H1A114.0C8A—C7A—C1A113.9 (4)
C2A—C1A—H1A114.0C9A—C7A—C4A114.3 (4)
C7A—C1A—H1A114.0C8A—C7A—C4A113.1 (4)
C11B—C2B—C1B120.6 (4)C1A—C7A—C4A92.5 (3)
C11B—C2B—C3B113.0 (4)C7B—C8B—H8D109.5
C1B—C2B—C3B99.4 (4)C7B—C8B—H8E109.5
C11B—C2B—H2B107.7H8D—C8B—H8E109.5
C1B—C2B—H2B107.7C7B—C8B—H8F109.5
C3B—C2B—H2B107.7H8D—C8B—H8F109.5
C3A—C2A—C1A101.2 (5)H8E—C8B—H8F109.5
C3A—C2A—C11A112.4 (4)C7A—C8A—H8A109.5
C1A—C2A—C11A120.3 (4)C7A—C8A—H8B109.5
C3A—C2A—H2A107.4H8A—C8A—H8B109.5
C1A—C2A—H2A107.4C7A—C8A—H8C109.5
C11A—C2A—H2A107.4H8A—C8A—H8C109.5
C12A—O3A—H3A109.5H8B—C8A—H8C109.5
C12B—O3B—H3B109.5C7B—C9B—H9D109.5
O1B—C3B—C4B129.1 (5)C7B—C9B—H9E109.5
O1B—C3B—C2B122.5 (5)H9D—C9B—H9E109.5
C4B—C3B—C2B108.4 (4)C7B—C9B—H9F109.5
O1A—C3A—C4A127.7 (5)H9D—C9B—H9F109.5
O1A—C3A—C2A124.8 (5)H9E—C9B—H9F109.5
C4A—C3A—C2A107.5 (5)C7A—C9A—H9A109.5
C3B—C4B—C10B115.9 (5)C7A—C9A—H9B109.5
C3B—C4B—C5B102.8 (4)H9A—C9A—H9B109.5
C10B—C4B—C5B115.5 (5)C7A—C9A—H9C109.5
C3B—C4B—C7B99.5 (4)H9A—C9A—H9C109.5
C10B—C4B—C7B119.0 (5)H9B—C9A—H9C109.5
C5B—C4B—C7B101.5 (4)C4A—C10A—H10A109.5
C3A—C4A—C10A115.9 (5)C4A—C10A—H10B109.5
C3A—C4A—C5A102.3 (4)H10A—C10A—H10B109.5
C10A—C4A—C5A117.2 (5)C4A—C10A—H10C109.5
C3A—C4A—C7A100.0 (4)H10A—C10A—H10C109.5
C10A—C4A—C7A117.6 (5)H10B—C10A—H10C109.5
C5A—C4A—C7A101.0 (4)C4B—C10B—H10D109.5
C4B—C5B—C6B105.2 (5)C4B—C10B—H10E109.5
C4B—C5B—H5C110.7H10D—C10B—H10E109.5
C6B—C5B—H5C110.7C4B—C10B—H10F109.5
C4B—C5B—H5D110.7H10D—C10B—H10F109.5
C6B—C5B—H5D110.7H10E—C10B—H10F109.5
H5C—C5B—H5D108.8C2B—C11B—C12B115.9 (4)
C6A—C5A—C4A106.5 (5)C2B—C11B—H11C108.3
C6A—C5A—H5A110.4C12B—C11B—H11C108.3
C4A—C5A—H5A110.4C2B—C11B—H11D108.3
C6A—C5A—H5B110.4C12B—C11B—H11D108.3
C4A—C5A—H5B110.4H11C—C11B—H11D107.4
H5A—C5A—H5B108.6C12A—C11A—C2A115.1 (4)
C1B—C6B—C5B101.4 (5)C12A—C11A—H11A108.5
C1B—C6B—H6C111.5C2A—C11A—H11A108.5
C5B—C6B—H6C111.5C12A—C11A—H11B108.5
C1B—C6B—H6D111.5C2A—C11A—H11B108.5
C5B—C6B—H6D111.5H11A—C11A—H11B107.5
H6C—C6B—H6D109.3O2B—C12B—O3B124.5 (5)
C1A—C6A—C5A102.1 (5)O2B—C12B—C11B123.7 (5)
C1A—C6A—H6A111.3O3B—C12B—C11B111.7 (5)
C5A—C6A—H6A111.3O2A—C12A—O3A122.6 (6)
C1A—C6A—H6B111.3O2A—C12A—C11A124.4 (5)
C5A—C6A—H6B111.3O3A—C12A—C11A113.0 (5)
C6B—C1B—C2B—C11B50.6 (6)C4A—C5A—C6A—C1A5.4 (6)
C7B—C1B—C2B—C11B160.3 (5)C6B—C1B—C7B—C9B62.5 (6)
C6B—C1B—C2B—C3B73.3 (5)C2B—C1B—C7B—C9B175.4 (5)
C7B—C1B—C2B—C3B36.4 (4)C6B—C1B—C7B—C8B172.2 (4)
C6A—C1A—C2A—C3A72.6 (5)C2B—C1B—C7B—C8B59.3 (5)
C7A—C1A—C2A—C3A35.9 (5)C6B—C1B—C7B—C4B56.5 (5)
C6A—C1A—C2A—C11A51.8 (6)C2B—C1B—C7B—C4B56.4 (4)
C7A—C1A—C2A—C11A160.4 (4)C3B—C4B—C7B—C1B54.5 (4)
C11B—C2B—C3B—O1B51.7 (7)C10B—C4B—C7B—C1B178.7 (5)
C1B—C2B—C3B—O1B179.2 (4)C5B—C4B—C7B—C1B50.7 (5)
C11B—C2B—C3B—C4B129.3 (5)C3B—C4B—C7B—C9B174.6 (5)
C1B—C2B—C3B—C4B0.2 (5)C10B—C4B—C7B—C9B58.6 (7)
C1A—C2A—C3A—O1A179.2 (4)C5B—C4B—C7B—C9B69.3 (5)
C11A—C2A—C3A—O1A51.2 (7)C3B—C4B—C7B—C8B64.3 (5)
C1A—C2A—C3A—C4A0.1 (5)C10B—C4B—C7B—C8B62.5 (7)
C11A—C2A—C3A—C4A129.5 (4)C5B—C4B—C7B—C8B169.6 (4)
O1B—C3B—C4B—C10B15.6 (8)C6A—C1A—C7A—C9A61.7 (5)
C2B—C3B—C4B—C10B163.3 (5)C2A—C1A—C7A—C9A174.0 (4)
O1B—C3B—C4B—C5B111.3 (6)C6A—C1A—C7A—C8A173.2 (4)
C2B—C3B—C4B—C5B69.8 (5)C2A—C1A—C7A—C8A60.9 (5)
O1B—C3B—C4B—C7B144.5 (5)C6A—C1A—C7A—C4A56.5 (5)
C2B—C3B—C4B—C7B34.4 (5)C2A—C1A—C7A—C4A55.9 (4)
O1A—C3A—C4A—C10A16.1 (8)C3A—C4A—C7A—C9A172.4 (4)
C2A—C3A—C4A—C10A163.2 (5)C10A—C4A—C7A—C9A61.3 (6)
O1A—C3A—C4A—C5A112.7 (6)C5A—C4A—C7A—C9A67.5 (5)
C2A—C3A—C4A—C5A68.1 (5)C3A—C4A—C7A—C8A63.2 (5)
O1A—C3A—C4A—C7A143.6 (5)C10A—C4A—C7A—C8A63.1 (6)
C2A—C3A—C4A—C7A35.7 (5)C5A—C4A—C7A—C8A168.0 (4)
C3B—C4B—C5B—C6B73.5 (6)C3A—C4A—C7A—C1A54.2 (4)
C10B—C4B—C5B—C6B159.3 (6)C10A—C4A—C7A—C1A179.5 (5)
C7B—C4B—C5B—C6B29.1 (6)C5A—C4A—C7A—C1A50.6 (4)
C3A—C4A—C5A—C6A72.7 (6)C1B—C2B—C11B—C12B70.9 (6)
C10A—C4A—C5A—C6A159.4 (5)C3B—C2B—C11B—C12B171.9 (4)
C7A—C4A—C5A—C6A30.3 (6)C3A—C2A—C11A—C12A167.6 (4)
C7B—C1B—C6B—C5B39.7 (6)C1A—C2A—C11A—C12A73.4 (7)
C2B—C1B—C6B—C5B69.0 (6)C2B—C11B—C12B—O2B158.6 (5)
C4B—C5B—C6B—C1B5.3 (6)C2B—C11B—C12B—O3B21.3 (7)
C2A—C1A—C6A—C5A68.3 (6)C2A—C11A—C12A—O2A156.0 (6)
C7A—C1A—C6A—C5A39.7 (6)C2A—C11A—C12A—O3A23.7 (7)

Experimental details

Crystal data
Chemical formulaC12H18O3
Mr210.26
Crystal system, space groupMonoclinic, P21
Temperature (K)296
a, b, c (Å)6.6423 (10), 14.734 (3), 11.817 (2)
β (°) 93.756 (13)
V3)1154.0 (4)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.38 × 0.30 × 0.18
Data collection
DiffractometerSiemens P4
diffractometer
Absorption correctionNumerical
(SHELXTL; Sheldrick, 1997)
Tmin, Tmax0.972, 0.986
No. of measured, independent and
observed [I > 2σ(I)] reflections
4574, 2110, 1161
Rint0.077
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.096, 0.99
No. of reflections2110
No. of parameters271
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.16, 0.16

Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL (Sheldrick, 1997), SHELXTL.

Selected geometric parameters (Å, º) top
O2A—C12A1.190 (6)O3A—C12A1.304 (6)
O2B—C12B1.171 (5)O3B—C12B1.326 (6)
O2B—C12B—C11B123.7 (5)O2A—C12A—C11A124.4 (5)
O3B—C12B—C11B111.7 (5)O3A—C12A—C11A113.0 (5)
 

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