Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801012223/tk6030sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801012223/tk6030Isup2.hkl |
CCDC reference: 170930
Key indicators
- Single-crystal X-ray study
- T = 295 K
- Mean (C-C) = 0.003 Å
- R factor = 0.043
- wR factor = 0.132
- Data-to-parameter ratio = 12.1
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
The title compound was synthesized using a modification of the method of Fischer et al. (1980) by the hydroboration of the unsaturated ester precursor followed by hydrolysis with sodium hydroxide. The modification (Vogel, 1989) involved the generation of diborane in situ by addition of the boron trifluoride–dietherate to a mixture of sodium borohydride and the ester precursor under a nitrogen atmosphere (Wermuth, 1995). Fractional crystallization of the isomeric mixture from acetone gave the 5-hydroxy and 6-hydroxy isomers. Crystals of the 6-hydroxy isomer (the title compound) suitable for X-ray analysis were obtained by slow evaporation from acetone.
Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999a); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1999b); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON for Windows (Spek, 1999); software used to prepare material for publication: TEXSAN for Windows.
C8H12O3 | F(000) = 336 |
Mr = 156.18 | Dx = 1.320 Mg m−3 |
Monoclinic, P21/a | Melting point: 434–435 K K |
Hall symbol: -P 2yab | Mo Kα radiation, λ = 0.71069 Å |
a = 11.821 (2) Å | Cell parameters from 25 reflections |
b = 10.7618 (18) Å | θ = 13.1–16.3° |
c = 6.3146 (11) Å | µ = 0.10 mm−1 |
β = 101.860 (14)° | T = 295 K |
V = 786.2 (2) Å3 | Prism, colourless |
Z = 4 | 0.50 × 0.35 × 0.20 mm |
Rigaku AFC-7R diffractometer | Rint = 0.033 |
Radiation source: Rigaku rotating anode | θmax = 27.5°, θmin = 2.6° |
Graphite monochromator | h = −8→15 |
ω–2θ scans | k = 0→13 |
2170 measured reflections | l = −8→8 |
1805 independent reflections | 3 standard reflections every 150 reflections |
1216 reflections with I > 2σ(I) | intensity decay: 1.2% |
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)] = 0.043 | All H-atom parameters refined |
wR(F2) = 0.132 | w = 1/[σ2(Fo2) + (0.0615P)2 + 0.1309P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
1805 reflections | Δρmax = 0.29 e Å−3 |
149 parameters | Δρmin = −0.17 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: 0.023 (5) |
C8H12O3 | V = 786.2 (2) Å3 |
Mr = 156.18 | Z = 4 |
Monoclinic, P21/a | Mo Kα radiation |
a = 11.821 (2) Å | µ = 0.10 mm−1 |
b = 10.7618 (18) Å | T = 295 K |
c = 6.3146 (11) Å | 0.50 × 0.35 × 0.20 mm |
β = 101.860 (14)° |
Rigaku AFC-7R diffractometer | Rint = 0.033 |
2170 measured reflections | 3 standard reflections every 150 reflections |
1805 independent reflections | intensity decay: 1.2% |
1216 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.132 | All H-atom parameters refined |
S = 1.04 | Δρmax = 0.29 e Å−3 |
1805 reflections | Δρmin = −0.17 e Å−3 |
149 parameters |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
O6 | 0.05140 (11) | 0.20706 (13) | 0.0912 (2) | 0.0482 (4) | |
O211 | 0.39684 (14) | 0.48698 (13) | 0.6884 (2) | 0.0665 (5) | |
O212 | 0.42875 (16) | 0.28610 (14) | 0.6870 (3) | 0.0725 (5) | |
C1 | 0.20068 (13) | 0.32132 (14) | 0.3489 (2) | 0.0347 (4) | |
C2 | 0.32589 (14) | 0.37061 (15) | 0.3625 (3) | 0.0378 (5) | |
C3 | 0.30626 (17) | 0.49228 (18) | 0.2292 (3) | 0.0482 (6) | |
C4 | 0.17567 (16) | 0.49212 (16) | 0.1404 (3) | 0.0479 (6) | |
C5 | 0.14741 (17) | 0.3864 (2) | −0.0220 (3) | 0.0503 (6) | |
C6 | 0.16179 (14) | 0.26883 (16) | 0.1199 (3) | 0.0392 (5) | |
C7 | 0.13049 (16) | 0.44147 (17) | 0.3333 (3) | 0.0463 (6) | |
C21 | 0.38711 (13) | 0.38930 (16) | 0.5946 (3) | 0.0415 (5) | |
H1 | 0.1935 (15) | 0.2647 (17) | 0.461 (3) | 0.040 (5)* | |
H2 | 0.3715 (17) | 0.3094 (18) | 0.301 (3) | 0.048 (5)* | |
H4 | 0.144 (2) | 0.577 (2) | 0.081 (4) | 0.068 (6)* | |
H6 | 0.059 (2) | 0.140 (2) | 0.159 (4) | 0.066 (7)* | |
H31 | 0.3284 (19) | 0.564 (2) | 0.328 (4) | 0.062 (6)* | |
H32 | 0.3488 (19) | 0.494 (2) | 0.114 (4) | 0.062 (6)* | |
H51 | 0.068 (2) | 0.3914 (19) | −0.105 (4) | 0.067 (6)* | |
H52 | 0.200 (2) | 0.3834 (19) | −0.123 (4) | 0.068 (7)* | |
H61 | 0.2205 (17) | 0.2087 (17) | 0.087 (3) | 0.043 (5)* | |
H71 | 0.0479 (18) | 0.4247 (18) | 0.305 (3) | 0.048 (5)* | |
H72 | 0.1523 (17) | 0.4918 (18) | 0.462 (4) | 0.054 (6)* | |
H212 | 0.464 (3) | 0.299 (3) | 0.826 (5) | 0.095 (9)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O6 | 0.0447 (7) | 0.0445 (7) | 0.0461 (7) | −0.0082 (6) | −0.0123 (5) | 0.0026 (6) |
O211 | 0.0797 (11) | 0.0528 (8) | 0.0564 (9) | 0.0017 (7) | −0.0109 (7) | −0.0170 (7) |
O212 | 0.0922 (12) | 0.0495 (8) | 0.0545 (8) | 0.0039 (8) | −0.0343 (8) | 0.0018 (7) |
C1 | 0.0381 (8) | 0.0324 (8) | 0.0303 (7) | −0.0010 (6) | −0.0005 (6) | 0.0029 (6) |
C2 | 0.0330 (8) | 0.0391 (9) | 0.0379 (8) | 0.0013 (7) | −0.0003 (6) | 0.0001 (7) |
C3 | 0.0461 (10) | 0.0453 (10) | 0.0491 (10) | −0.0076 (8) | 0.0002 (8) | 0.0101 (8) |
C4 | 0.0457 (10) | 0.0373 (9) | 0.0560 (11) | 0.0029 (7) | −0.0004 (8) | 0.0145 (8) |
C5 | 0.0472 (10) | 0.0627 (12) | 0.0361 (8) | −0.0044 (9) | −0.0032 (7) | 0.0119 (8) |
C6 | 0.0355 (8) | 0.0433 (9) | 0.0340 (8) | 0.0015 (7) | −0.0039 (6) | −0.0034 (7) |
C7 | 0.0424 (10) | 0.0421 (10) | 0.0535 (10) | 0.0058 (8) | 0.0077 (8) | −0.0027 (8) |
C21 | 0.0338 (8) | 0.0415 (9) | 0.0438 (9) | −0.0032 (7) | −0.0044 (6) | −0.0005 (7) |
O6—C6 | 1.442 (2) | C4—C7 | 1.528 (3) |
O6—H6 | 0.83 (2) | C5—C6 | 1.540 (3) |
O211—C21 | 1.200 (2) | C1—H1 | 0.951 (18) |
O212—C21 | 1.303 (2) | C2—H2 | 0.98 (2) |
O212—H212 | 0.90 (3) | C3—H31 | 0.99 (2) |
C1—C6 | 1.532 (2) | C3—H32 | 0.97 (2) |
C1—C2 | 1.558 (2) | C4—H4 | 1.03 (2) |
C1—C7 | 1.529 (2) | C5—H51 | 0.98 (2) |
C2—C21 | 1.509 (3) | C5—H52 | 0.98 (2) |
C2—C3 | 1.548 (3) | C6—H61 | 1.00 (2) |
C3—C4 | 1.530 (3) | C7—H71 | 0.97 (2) |
C4—C5 | 1.522 (3) | C7—H72 | 0.97 (2) |
C6—O6—H6 | 109.6 (17) | C3—C2—H2 | 112.7 (11) |
C21—O212—H212 | 111 (2) | C21—C2—H2 | 106.3 (11) |
C6—C1—C7 | 101.39 (12) | C2—C3—H31 | 109.0 (14) |
C2—C1—C6 | 105.96 (13) | C2—C3—H32 | 112.5 (13) |
C2—C1—C7 | 102.27 (13) | C4—C3—H31 | 110.3 (13) |
C3—C2—C21 | 113.82 (14) | C4—C3—H32 | 111.5 (14) |
C1—C2—C21 | 111.07 (14) | H31—C3—H32 | 110.3 (19) |
C1—C2—C3 | 102.91 (14) | C3—C4—H4 | 113.4 (13) |
C2—C3—C4 | 103.03 (15) | C5—C4—H4 | 113.9 (14) |
C3—C4—C5 | 108.23 (15) | C7—C4—H4 | 116.6 (14) |
C3—C4—C7 | 101.53 (15) | C4—C5—H51 | 111.9 (13) |
C5—C4—C7 | 101.90 (15) | C4—C5—H52 | 112.5 (13) |
C4—C5—C6 | 103.86 (15) | C6—C5—H51 | 109.6 (13) |
C1—C6—C5 | 102.83 (14) | C6—C5—H52 | 110.1 (13) |
O6—C6—C1 | 112.13 (14) | H51—C5—H52 | 109 (2) |
O6—C6—C5 | 108.47 (14) | O6—C6—H61 | 108.9 (11) |
C1—C7—C4 | 94.54 (14) | C1—C6—H61 | 110.3 (11) |
O212—C21—C2 | 112.52 (16) | C5—C6—H61 | 114.1 (11) |
O211—C21—O212 | 122.43 (18) | C1—C7—H71 | 111.5 (12) |
O211—C21—C2 | 125.05 (16) | C1—C7—H72 | 111.9 (12) |
C2—C1—H1 | 114.0 (11) | C4—C7—H71 | 115.0 (11) |
C6—C1—H1 | 114.3 (11) | C4—C7—H72 | 113.2 (13) |
C7—C1—H1 | 117.4 (11) | H71—C7—H72 | 110.0 (17) |
C1—C2—H2 | 110.1 (12) | ||
C6—C1—C2—C21 | −163.00 (13) | C3—C2—C21—O211 | 17.1 (3) |
C6—C1—C2—C3 | 74.84 (15) | C1—C2—C3—C4 | −4.73 (17) |
C7—C1—C6—C5 | 36.32 (16) | C1—C2—C21—O211 | −98.5 (2) |
C2—C1—C7—C4 | 53.59 (14) | C1—C2—C21—O212 | 80.92 (18) |
C7—C1—C2—C3 | −30.96 (16) | C2—C3—C4—C5 | −67.85 (18) |
C7—C1—C2—C21 | 91.20 (15) | C2—C3—C4—C7 | 38.93 (17) |
C2—C1—C6—O6 | 173.56 (13) | C3—C4—C5—C6 | 72.99 (18) |
C2—C1—C6—C5 | −70.12 (16) | C7—C4—C5—C6 | −33.54 (18) |
C7—C1—C6—O6 | −80.00 (16) | C5—C4—C7—C1 | 54.67 (16) |
C6—C1—C7—C4 | −55.73 (15) | C3—C4—C7—C1 | −57.01 (15) |
C3—C2—C21—O212 | −163.50 (16) | C4—C5—C6—C1 | −1.71 (18) |
C21—C2—C3—C4 | −125.02 (15) | C4—C5—C6—O6 | 117.20 (16) |
Experimental details
Crystal data | |
Chemical formula | C8H12O3 |
Mr | 156.18 |
Crystal system, space group | Monoclinic, P21/a |
Temperature (K) | 295 |
a, b, c (Å) | 11.821 (2), 10.7618 (18), 6.3146 (11) |
β (°) | 101.860 (14) |
V (Å3) | 786.2 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.50 × 0.35 × 0.20 |
Data collection | |
Diffractometer | Rigaku AFC-7R diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2170, 1805, 1216 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.132, 1.04 |
No. of reflections | 1805 |
No. of parameters | 149 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.29, −0.17 |
Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1999a), MSC/AFC Diffractometer Control Software, TEXSAN for Windows (Molecular Structure Corporation, 1999b), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON for Windows (Spek, 1999), TEXSAN for Windows.
Racemic 6-exo-hydroxybicyclo[2.2.1]heptane-2-exo-carboxylic acid, (I), was first reported in 1969 together with the isomeric 5-exo-hydroxy isomer (Beckmann et al., 1969) with which it forms in the normal synthetic route. The hydroboration procedure used here in the preparation (Fischer et al., 1980) gives predominantly the 6-exo-hydroxy isomer, whereas the oxymercuration/demercuration procedure of Beckmann et al. (1969) gives predominantly the 5-exo-hydroxy isomer. The crystal structure determination of (I) shows the relatively inflexible norbornane cage which is similar to other norbornane carboxylic acids (Apgar & Ludwig, 1972; Albinati et al., 1973), with both the carboxylic acid and hydroxy groups exo-related (Fig. 1). The torsion angles C1–C2–C21–O212 and C2–C1–C6–O6 are 80.9 (2) and 173.6 (1)°, respectively. The carboxylic acid O atoms associate with the hydroxy groups of two different acids [O212—H212···O6i 2.665 (2) Å and O—H···O 167 (2)°; O6—H6···O211ii, 2.752 (2) Å, O—H···O, 170 (2)°; symmetry codes: (i) 1/2 + x, 1/2 - y, 1 + z; (ii) 1/2 - x, -1/2 + y, 1 - z], forming cyclic centrosymmetric 12-membered R44(12) rings (Fig. 2). These then form into an infinite two-dimensional structure. This association is different from the common R22(8) cyclic A—A dimers or the more unusual catemer structures found among the monofunctional carboxylic acids (Leiserowitz, 1976).