Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100005813/fr1268sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100005813/fr1268Isup2.hkl |
CCDC reference: 147676
To a stirred solution of hydroquinone (2.2 g, 20 mmol) and boron trifluoride etherate (0.3 ml) in dioxane (15 ml) at 300 K, a solution of 2-methylbut-3-ene-2-ol (2.6 g, 20 mmol) was added dropwise over 30 min. The reaction mixture was stirred for a further hour at 300 K and then quenched using moist ether; the mixture was diluted with water (100 ml) and extracted with ether (3 x 50 ml). The ether layer was dried over anhydrous Na2SO4, the solvent was removed and the residue chromatographed over silica gel to afford (I). It was recrystallized from chloroform as colourless crystals, m.p. 348 K (literature m.p. 348–49 K; Nilsson et al., 1968).
The hydroxyl hydrogen atom was added from an electron density map and freely refined. Other hydrogen atoms were added at calculated positions and refined using a riding model with C—H distances 0.95–0.99 Å. H atoms were given isotropic displacement parameters equal to 1.2 (or 1.5 for methyl H atoms) times the equivalent isotropic displacement parameter of their parent atoms.
Data collection: SMART (Siemens, 1994a); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: SHELXTL/PC (Siemens, 1994b); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC; software used to prepare material for publication: SHELXTL/PC.
Fig. 1. Atomic numbering with displacement ellipsoids at the 50% level. | |
Fig. 2. Packing diagram viewed down the c axis. |
C11H14O2 | Dx = 1.206 Mg m−3 |
Mr = 178.22 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, I41/a | Cell parameters from 4204 reflections |
Hall symbol: -I 4ad | θ = 2.3–27.5° |
a = 25.1353 (12) Å | µ = 0.08 mm−1 |
c = 6.2139 (4) Å | T = 180 K |
V = 3925.8 (4) Å3 | Block, colourless |
Z = 16 | 0.30 × 0.22 × 0.20 mm |
F(000) = 1536 |
Siemens SMART CCD area-detector diffractometer | 2237 independent reflections |
Radiation source: normal-focus sealed tube | 1510 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.047 |
Detector resolution: 8.192 pixels mm-1 | θmax = 27.5°, θmin = 2.3° |
ω scans | h = −31→32 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −21→32 |
Tmin = 0.976, Tmax = 0.984 | l = −8→6 |
11034 measured reflections |
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)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.115 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0488P)2 + 1.8457P] where P = (Fo2 + 2Fc2)/3 |
2237 reflections | (Δ/σ)max < 0.001 |
124 parameters | Δρmax = 0.14 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
C11H14O2 | Z = 16 |
Mr = 178.22 | Mo Kα radiation |
Tetragonal, I41/a | µ = 0.08 mm−1 |
a = 25.1353 (12) Å | T = 180 K |
c = 6.2139 (4) Å | 0.30 × 0.22 × 0.20 mm |
V = 3925.8 (4) Å3 |
Siemens SMART CCD area-detector diffractometer | 2237 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1510 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.984 | Rint = 0.047 |
11034 measured reflections |
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.115 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 0.14 e Å−3 |
2237 reflections | Δρmin = −0.24 e Å−3 |
124 parameters |
Experimental. UV(MeOH) λmax(nm): 297 and 268; IR(KBr) νmax/cm−1: 3202, 1594, 1380, 1367, 1353, 1322, 1289, 1249, 1201, 1160, 1149, 1122, 948, 923, 894, 864, 819, 793, 620, 579, 501, 470; 1H NMR (δ, CDCl3, 300 MHz): 1.30 (6H, s, 2xCH3), 1.75 (2H, t, J = 6.5 Hz, H-3), 2.69 (2H, t, J = 6.5 Hz, H-4), 5.36 (1H, s, C-6 OH) & 6.55–6.65 (3H, m, H-5, H-7 & H-8); 13C NMR (δ, CDCl3, 75 MHz): 22.60 (C-3), 26.70 (2xCH3), 32.77 (C-4) 74.01 (C-2), 114.59, 115.55, 117.78 (C-5, C-7 & C-8), 121.83 (C-4a), 147.73 & 148.57 (C-6 & C-8a); EIMS, m/z (% rel. int.): [M+] 178 (53), 163 (18), 123 (95), 107 (43), 94 (100), 77 (40), 65 (58). |
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. The temperature of the crystal was controlled using the Oxford Cryosystem Cryostream Cooler (Cosier & Glazer, 1986). Data were collected over a hemisphere of reciprocal space, by a combination of three sets of exposures. Each set had a different ϕ angle for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal to detector distance was 5.01 cm. Coverage of the unique set was over 99% complete to at least 27° in θ. Crystal decay was monitored by repeating the initial frames at the end of the data collection and analyzing the duplicate reflections. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.50790 (4) | 0.43699 (4) | 0.80152 (18) | 0.0355 (3) | |
O2 | 0.31070 (4) | 0.49708 (5) | 0.49208 (19) | 0.0354 (3) | |
H2 | 0.2935 (9) | 0.5180 (9) | 0.587 (4) | 0.070 (7)* | |
C2 | 0.53615 (6) | 0.39350 (6) | 0.6972 (3) | 0.0325 (4) | |
C3 | 0.53548 (6) | 0.40296 (7) | 0.4561 (3) | 0.0362 (4) | |
H3A | 0.5559 | 0.3745 | 0.3836 | 0.043* | |
H3B | 0.5530 | 0.4373 | 0.4241 | 0.043* | |
C4 | 0.47889 (7) | 0.40384 (7) | 0.3671 (3) | 0.0381 (4) | |
H4A | 0.4790 | 0.4199 | 0.2216 | 0.046* | |
H4B | 0.4655 | 0.3669 | 0.3545 | 0.046* | |
C5 | 0.39220 (6) | 0.45176 (6) | 0.4434 (3) | 0.0310 (4) | |
H5A | 0.3803 | 0.4423 | 0.3033 | 0.037* | |
C6 | 0.35948 (6) | 0.48131 (6) | 0.5748 (3) | 0.0282 (4) | |
C7 | 0.37583 (6) | 0.49519 (6) | 0.7802 (3) | 0.0311 (4) | |
H7A | 0.3531 | 0.5152 | 0.8716 | 0.037* | |
C8 | 0.42549 (6) | 0.47954 (6) | 0.8503 (3) | 0.0323 (4) | |
H8A | 0.4371 | 0.4892 | 0.9903 | 0.039* | |
C9 | 0.45861 (6) | 0.44976 (6) | 0.7182 (2) | 0.0287 (4) | |
C10 | 0.44249 (6) | 0.43542 (6) | 0.5120 (3) | 0.0291 (4) | |
C11 | 0.59202 (6) | 0.39632 (7) | 0.7880 (3) | 0.0422 (4) | |
H11A | 0.6087 | 0.4299 | 0.7445 | 0.063* | |
H11B | 0.6130 | 0.3664 | 0.7328 | 0.063* | |
H11C | 0.5905 | 0.3944 | 0.9454 | 0.063* | |
C12 | 0.50900 (7) | 0.34199 (7) | 0.7608 (3) | 0.0450 (5) | |
H12A | 0.5120 | 0.3370 | 0.9167 | 0.067* | |
H12B | 0.5261 | 0.3122 | 0.6865 | 0.067* | |
H12C | 0.4714 | 0.3436 | 0.7203 | 0.067* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0316 (6) | 0.0410 (7) | 0.0338 (7) | 0.0081 (5) | −0.0037 (5) | −0.0027 (5) |
O2 | 0.0270 (6) | 0.0378 (7) | 0.0415 (7) | 0.0041 (5) | −0.0054 (5) | −0.0121 (6) |
C2 | 0.0287 (8) | 0.0320 (8) | 0.0368 (9) | 0.0045 (7) | 0.0044 (7) | 0.0043 (7) |
C3 | 0.0329 (9) | 0.0394 (9) | 0.0364 (10) | 0.0060 (7) | 0.0073 (7) | 0.0039 (8) |
C4 | 0.0400 (10) | 0.0414 (10) | 0.0329 (9) | 0.0112 (8) | 0.0019 (8) | −0.0042 (8) |
C5 | 0.0322 (8) | 0.0324 (8) | 0.0284 (9) | 0.0008 (6) | −0.0020 (7) | −0.0040 (7) |
C6 | 0.0250 (8) | 0.0256 (8) | 0.0340 (9) | −0.0016 (6) | −0.0013 (7) | −0.0010 (7) |
C7 | 0.0315 (8) | 0.0309 (8) | 0.0310 (9) | 0.0011 (6) | 0.0034 (7) | −0.0037 (7) |
C8 | 0.0349 (9) | 0.0366 (9) | 0.0252 (8) | 0.0004 (7) | −0.0005 (7) | −0.0027 (7) |
C9 | 0.0277 (8) | 0.0292 (8) | 0.0291 (8) | 0.0000 (6) | 0.0007 (7) | 0.0028 (7) |
C10 | 0.0307 (8) | 0.0270 (8) | 0.0297 (9) | 0.0013 (6) | 0.0033 (7) | 0.0008 (7) |
C11 | 0.0323 (9) | 0.0470 (11) | 0.0474 (11) | 0.0050 (8) | −0.0009 (8) | 0.0041 (9) |
C12 | 0.0372 (10) | 0.0400 (10) | 0.0577 (12) | 0.0032 (8) | 0.0029 (9) | 0.0157 (9) |
O1—C9 | 1.3805 (19) | C5—C10 | 1.396 (2) |
O1—C2 | 1.4560 (19) | C5—H5A | 0.9500 |
O2—C6 | 1.3873 (18) | C6—C7 | 1.386 (2) |
O2—H2 | 0.90 (2) | C7—C8 | 1.379 (2) |
C2—C11 | 1.515 (2) | C7—H7A | 0.9500 |
C2—C12 | 1.516 (2) | C8—C9 | 1.388 (2) |
C2—C3 | 1.517 (2) | C8—H8A | 0.9500 |
C3—C4 | 1.526 (2) | C9—C10 | 1.391 (2) |
C3—H3A | 0.9900 | C11—H11A | 0.9800 |
C3—H3B | 0.9900 | C11—H11B | 0.9800 |
C4—C10 | 1.509 (2) | C11—H11C | 0.9800 |
C4—H4A | 0.9900 | C12—H12A | 0.9800 |
C4—H4B | 0.9900 | C12—H12B | 0.9800 |
C5—C6 | 1.376 (2) | C12—H12C | 0.9800 |
C9—O1—C2 | 116.44 (12) | C7—C6—O2 | 122.10 (14) |
C6—O2—H2 | 110.4 (14) | C8—C7—C6 | 119.17 (15) |
O1—C2—C11 | 104.54 (13) | C8—C7—H7A | 120.4 |
O1—C2—C12 | 107.80 (13) | C6—C7—H7A | 120.4 |
C11—C2—C12 | 111.11 (14) | C7—C8—C9 | 120.66 (15) |
O1—C2—C3 | 108.45 (13) | C7—C8—H8A | 119.7 |
C11—C2—C3 | 111.76 (14) | C9—C8—H8A | 119.7 |
C12—C2—C3 | 112.72 (15) | O1—C9—C8 | 116.22 (14) |
C2—C3—C4 | 111.74 (14) | O1—C9—C10 | 123.13 (14) |
C2—C3—H3A | 109.3 | C8—C9—C10 | 120.63 (14) |
C4—C3—H3A | 109.3 | C9—C10—C5 | 117.96 (14) |
C2—C3—H3B | 109.3 | C9—C10—C4 | 120.59 (14) |
C4—C3—H3B | 109.3 | C5—C10—C4 | 121.44 (15) |
H3A—C3—H3B | 107.9 | C2—C11—H11A | 109.5 |
C10—C4—C3 | 110.89 (14) | C2—C11—H11B | 109.5 |
C10—C4—H4A | 109.5 | H11A—C11—H11B | 109.5 |
C3—C4—H4A | 109.5 | C2—C11—H11C | 109.5 |
C10—C4—H4B | 109.5 | H11A—C11—H11C | 109.5 |
C3—C4—H4B | 109.5 | H11B—C11—H11C | 109.5 |
H4A—C4—H4B | 108.0 | C2—C12—H12A | 109.5 |
C6—C5—C10 | 121.24 (15) | C2—C12—H12B | 109.5 |
C6—C5—H5A | 119.4 | H12A—C12—H12B | 109.5 |
C10—C5—H5A | 119.4 | C2—C12—H12C | 109.5 |
C5—C6—C7 | 120.34 (14) | H12A—C12—H12C | 109.5 |
C5—C6—O2 | 117.55 (14) | H12B—C12—H12C | 109.5 |
C9—O1—C2—C11 | 168.31 (13) | C2—O1—C9—C8 | 162.00 (13) |
C9—O1—C2—C12 | −73.38 (17) | C2—O1—C9—C10 | −19.7 (2) |
C9—O1—C2—C3 | 48.95 (17) | C7—C8—C9—O1 | 178.76 (13) |
O1—C2—C3—C4 | −61.43 (18) | C7—C8—C9—C10 | 0.4 (2) |
C11—C2—C3—C4 | −176.15 (14) | O1—C9—C10—C5 | −178.38 (14) |
C12—C2—C3—C4 | 57.86 (19) | C8—C9—C10—C5 | −0.2 (2) |
C2—C3—C4—C10 | 43.3 (2) | O1—C9—C10—C4 | 0.7 (2) |
C10—C5—C6—C7 | −0.5 (2) | C8—C9—C10—C4 | 178.96 (15) |
C10—C5—C6—O2 | 178.37 (14) | C6—C5—C10—C9 | 0.2 (2) |
C5—C6—C7—C8 | 0.7 (2) | C6—C5—C10—C4 | −178.92 (15) |
O2—C6—C7—C8 | −178.08 (14) | C3—C4—C10—C9 | −13.3 (2) |
C6—C7—C8—C9 | −0.7 (2) | C3—C4—C10—C5 | 165.84 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2i | 0.90 (2) | 1.77 (2) | 2.6608 (12) | 172 (2) |
Symmetry code: (i) −y+3/4, x+1/4, z+1/4. |
Experimental details
Crystal data | |
Chemical formula | C11H14O2 |
Mr | 178.22 |
Crystal system, space group | Tetragonal, I41/a |
Temperature (K) | 180 |
a, c (Å) | 25.1353 (12), 6.2139 (4) |
V (Å3) | 3925.8 (4) |
Z | 16 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.30 × 0.22 × 0.20 |
Data collection | |
Diffractometer | Siemens SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.976, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11034, 2237, 1510 |
Rint | 0.047 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.115, 1.02 |
No. of reflections | 2237 |
No. of parameters | 124 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.14, −0.24 |
Computer programs: SMART (Siemens, 1994a), SAINT (Siemens, 1995), SAINT, SHELXTL/PC (Siemens, 1994b), SHELXL97 (Sheldrick, 1997), SHELXTL/PC.
O1—C9 | 1.3805 (19) | O2—C6 | 1.3873 (18) |
O1—C2 | 1.4560 (19) | ||
O1—C2—C3—C4 | −61.43 (18) | C2—O1—C9—C10 | −19.7 (2) |
C2—C3—C4—C10 | 43.3 (2) | C3—C4—C10—C9 | −13.3 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2i | 0.90 (2) | 1.77 (2) | 2.6608 (12) | 172 (2) |
Symmetry code: (i) −y+3/4, x+1/4, z+1/4. |
Chromans are known to possess pronounced antioxidant activity (Cotelle et al., 1991, 1992; Pearce et al., 1994). This basic unit is also present in α-tocopherol which is a commercial, naturally occurring antioxidant. Such compounds are also used as colour photographic recording materials (Fujiwhara et al., 1978) and in pharmaceutical compositions (Evans et al., 1981). We have prepared several chromanols for biotransformation studies for structure-activity relationship studies as antitumour agents (Parmar et al., 1994, 1997). In one such reaction, the title compound, (I), was obtained as a side product during the condensation of hydroquinone with 2-methylbut-3-ene-2-ol in the form of colourless crystals; its structure was determined in order to assign its constitution unambiguously. \sch
The molecular structure is illustrated in Fig. 1 and selected geometric parameters are given in Table 1. Bond lengths and angles are largely unexceptional. An analysis (Cremer & Pople, 1975; Farrugia, 1998) of the puckering in the six-membered pyran ring gives a puckering amplitude of 0.485 Å, with θ = 49.9 and ϕ = 85.95°; this corresponds to a half-chair conformation. The C12 methyl group occupies an axial position, whilst the hydrogen atoms are attached to C4 in axial and bisectional orientations.
The title compound has been briefly reported in an earlier study (Mukai et al., 1993) concerned with the extent of orbital overlap between the 2p lone pair on the ring oxygen with the aromatic π-electron system in a series of related compounds. It was argued that the larger this overlap, the smaller the torsion angle C2—O1—C9—C10. This torsion angle was given as 18.0° based upon an X-ray investigation and as 20.1° from ab initio calculations; the value of −19.7 (2)° obtained in the present study is in excellent agreement with that obtained from the theoretical study.
The hydroxyl oxygen atoms form inter-molecular hydrogen bonds with two other molecules (Table 2 and Fig. 2) thus producing infinite polymeric spiral chains around the fourfold screw axes.