Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100000731/jz1387sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100000731/jz13872sup2.hkl |
CCDC reference: 144649
Compound (II) was prepared as follows. A mixture of (2R,3R)-2-hydroxy-2-(2-hydroxy-4-methoxyphenyl)-3-methoxy-3-phenylpropan-1-oic acid, (I) (0.3 g, 0.94 mmol; Brady et al., 1989) and acetic anhydride (10 ml) was heated under reflux for 2 h. The cooled solution was poured into iced water (30 ml). The resulting yellow solid was collected and crystallized from ethanol as yellow-green needles of (II) (yield 0.079 g, 30%; m.p. 435–437 K). Analysis, found: C 72.05, H 5.01%; C17H14O4 requires: C 72.32, H 5.01%; IR νmax,KBr, cm-1: 1762, 1626 and 1587; λmax, 95% EtOH, nm: 206.1 (ε/dm3mol-1cm-1 23, 709), 233.2 (13, 923), 256.6 (11, 895) and 342 (13, 861); 1H NMR, 270 MHz, CDCl3, p.p.m.: 3.71 (s, 3H), 3.83 (s, 3H), 6.66 (d, J = 2.2 Hz, 1H), 6.70 (dd, J = 8.2, 2.4 Hz, 1H), 7.41 (m, 2H), 7.52 (m, 3H), and 7.70 (d, J = 8.2 Hz, 1H); 13C NMR, 67.80 MHz, CDCl3, p.p.m.: 55.63, 57.72, 96.63, 103.18, 109.19, 116.82, 123.87, 128.74, 128.99, 130.32, 130.56, 152.56, 159.95, 168.02, and 168.21; mass spectroscopy m/z (E·I.): 282.1 (M+,100), 267.1 (23), 239.1 (50), 211.1 (3) and 105 (50%). Evaporation of the filtrate to half its volume yielded cubes of (αR,βR)-3-acetoxy-6-methoxy-3-[(R)-methoxyphenylmethyl]benzo[b]furan- 2(3H)-one, (III) (yield 0.129 g, 40%; m.p. 409–411 K). Analysis, found: C 66.94, H 5.35%; C19H18O6 requires: C 66.66, H 5.30%; IR νmax, KBr, cm-1: 1821, 1752 and 1635; 1H NMR, 270 MHz, CDCl3, p.p.m.: 2.03 (s, 3H), 3.24 (s, 3H), 3.79 (s, 3H), 4.78 (s, 1H), 6.14 (d, 8.2 Hz, 1H), 6.46 (dd, J = 8.2, 2.3 Hz, 1H), 6.71 (d, J = 2.3 Hz, 1H), 7.32 (m, 2H) and 7.42 (m,3H); 13C NMR, 67.80 MHz, CDCl3, p.p.m.: 20.37, 55.55, 57.72, 79.33, 83.93, 97.28, 109.29, 113.70, 126.02, 127.90, 128.51, 128.81, 134.5, 156.30, 162.05, 168.45, and 173.84; mass spectroscopy, m/z (E·I.) 342 (M+,1), 282 (3), 252 (4), 209 (5), 165 (2) and 121 (100%). An alternative synthesis of (II) proceeds as follows. A mixture of 3-benzoyl-6-methoxybenzofuran-2-one, (IV) (0.076 g, 0.284 mmol; Brady, Burke & O'Sullivan, unpublished results), dimethylsulfate (0.1 ml, 1.06 mmol), anhydrous potassium carbonate (3 g, 21.7 mmol) and dry acetone (20 ml) was heated under reflux for 2 h. The cooled mixture was filtered free of inorganic matter and diluted with ice and water. The resulting precipitate crystallized from ethanol as green-yellow needles of (II) (yield 0.05 g, 62%; m.p. 436 K). All the chiral compounds discussed or shown in this paper existed as racemic mixtures; only one member of the enantiomeric pair is mentioned in each case for the sake of convenience.
The positions of the H atoms were determined from difference electron density maps and they were refined with isotropic displacement parameters. C—H bond lengths range between 0.960 (15) and 1.062 (15) Å.
Data collection: IPDS Software (Stoe & Cie, 1999); cell refinement: IPDS Software; data reduction: IPDS (Stoe & Cie, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990) and PLUTON (Spek, 1991); software used to prepare material for publication: SHELXL97.
C17H14O4 | F(000) = 592 |
Mr = 282.28 | Dx = 1.396 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 10.5235 (8) Å | Cell parameters from 8000 reflections |
b = 7.1136 (3) Å | θ = 2.7–30.3° |
c = 18.2587 (13) Å | µ = 0.10 mm−1 |
β = 100.632 (9)° | T = 173 K |
V = 1343.38 (15) Å3 | Plate, green-yellow |
Z = 4 | 0.54 × 0.35 × 0.06 mm |
STOE IPDS diffractometer | 3849 independent reflections |
Radiation source: fine-focus sealed tube | 2237 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
ϕ oscillation scan | θmax = 30.3°, θmin = 2.7° |
Absorption correction: numerical (Coppens et al., 1965) | h = −14→14 |
Tmin = 0.948, Tmax = 0.994 | k = 0→9 |
13623 measured reflections | l = 0→25 |
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)] = 0.034 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.067 | All H-atom parameters refined |
S = 1.01 | w = 1/[σ2(Fo2) + (0.02P)2] where P = (Fo2 + 2Fc2)/3 |
3849 reflections | (Δ/σ)max = 0.001 |
246 parameters | Δρmax = 0.22 e Å−3 |
0 restraints | Δρmin = −0.19 e Å−3 |
C17H14O4 | V = 1343.38 (15) Å3 |
Mr = 282.28 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.5235 (8) Å | µ = 0.10 mm−1 |
b = 7.1136 (3) Å | T = 173 K |
c = 18.2587 (13) Å | 0.54 × 0.35 × 0.06 mm |
β = 100.632 (9)° |
STOE IPDS diffractometer | 3849 independent reflections |
Absorption correction: numerical (Coppens et al., 1965) | 2237 reflections with I > 2σ(I) |
Tmin = 0.948, Tmax = 0.994 | Rint = 0.037 |
13623 measured reflections |
R[F2 > 2σ(F2)] = 0.034 | 0 restraints |
wR(F2) = 0.067 | All H-atom parameters refined |
S = 1.01 | Δρmax = 0.22 e Å−3 |
3849 reflections | Δρmin = −0.19 e Å−3 |
246 parameters |
Experimental. see text |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.14312 (8) | 0.45269 (13) | 0.04033 (5) | 0.0239 (2) | |
C2 | 0.21942 (11) | 0.4314 (2) | −0.01451 (7) | 0.0217 (3) | |
C3 | 0.24854 (11) | 0.23111 (18) | −0.01970 (6) | 0.0181 (2) | |
O2 | 0.24959 (9) | 0.56855 (14) | −0.04549 (5) | 0.0299 (2) | |
O6 | −0.05484 (8) | −0.00156 (14) | 0.18274 (5) | 0.0302 (2) | |
C4 | 0.16315 (11) | −0.05095 (19) | 0.05131 (6) | 0.0196 (3) | |
C5 | 0.08338 (11) | −0.09014 (19) | 0.10206 (6) | 0.0211 (3) | |
C6 | 0.02358 (11) | 0.0556 (2) | 0.13461 (6) | 0.0220 (3) | |
C7 | 0.04185 (11) | 0.2424 (2) | 0.11771 (7) | 0.0220 (3) | |
C8 | 0.12091 (11) | 0.27452 (19) | 0.06667 (6) | 0.0199 (3) | |
C9 | 0.18271 (11) | 0.13518 (18) | 0.03340 (6) | 0.0182 (3) | |
C10 | 0.32742 (11) | 0.16059 (18) | −0.06380 (6) | 0.0188 (3) | |
O10 | 0.35617 (8) | −0.02281 (13) | −0.05469 (5) | 0.0258 (2) | |
C11 | −0.11999 (15) | 0.1424 (3) | 0.21584 (9) | 0.0364 (4) | |
C12 | 0.43437 (14) | −0.1146 (2) | −0.10131 (8) | 0.0260 (3) | |
C13 | 0.38169 (11) | 0.27525 (18) | −0.11886 (6) | 0.0187 (3) | |
C14 | 0.30141 (12) | 0.3359 (2) | −0.18365 (7) | 0.0247 (3) | |
C15 | 0.35007 (13) | 0.4492 (2) | −0.23387 (7) | 0.0285 (3) | |
C16 | 0.47850 (13) | 0.5019 (2) | −0.21936 (7) | 0.0273 (3) | |
C17 | 0.55936 (13) | 0.4398 (2) | −0.15550 (7) | 0.0282 (3) | |
C18 | 0.51135 (12) | 0.3256 (2) | −0.10526 (7) | 0.0242 (3) | |
H4 | 0.2027 (12) | −0.155 (2) | 0.0279 (7) | 0.026 (4)* | |
H5 | 0.0637 (12) | −0.231 (2) | 0.1161 (7) | 0.029 (4)* | |
H7 | −0.0007 (12) | 0.346 (2) | 0.1369 (7) | 0.028 (4)* | |
H111 | −0.1721 (14) | 0.071 (2) | 0.2490 (8) | 0.047 (4)* | |
H112 | −0.0558 (15) | 0.226 (3) | 0.2494 (9) | 0.052 (5)* | |
H113 | −0.1778 (15) | 0.217 (2) | 0.1764 (9) | 0.047 (5)* | |
H121 | 0.3967 (13) | −0.089 (2) | −0.1539 (8) | 0.035 (4)* | |
H122 | 0.5262 (14) | −0.069 (2) | −0.0883 (8) | 0.035 (4)* | |
H123 | 0.4284 (14) | −0.253 (3) | −0.0926 (8) | 0.044 (4)* | |
H14 | 0.2063 (14) | 0.305 (2) | −0.1933 (8) | 0.040 (4)* | |
H15 | 0.2907 (13) | 0.492 (2) | −0.2812 (8) | 0.034 (4)* | |
H16 | 0.5114 (13) | 0.586 (2) | −0.2540 (8) | 0.032 (4)* | |
H17 | 0.6518 (14) | 0.481 (2) | −0.1449 (8) | 0.042 (4)* | |
H18 | 0.5673 (12) | 0.286 (2) | −0.0575 (8) | 0.034 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0281 (4) | 0.0150 (5) | 0.0315 (5) | 0.0014 (4) | 0.0128 (4) | −0.0017 (4) |
C2 | 0.0199 (6) | 0.0207 (7) | 0.0249 (6) | 0.0000 (5) | 0.0049 (5) | −0.0001 (5) |
C3 | 0.0194 (5) | 0.0153 (7) | 0.0196 (6) | −0.0002 (5) | 0.0033 (4) | 0.0007 (5) |
O2 | 0.0376 (5) | 0.0172 (5) | 0.0383 (5) | −0.0003 (4) | 0.0157 (4) | 0.0028 (4) |
O6 | 0.0339 (5) | 0.0310 (6) | 0.0308 (5) | 0.0004 (4) | 0.0189 (4) | 0.0010 (4) |
C4 | 0.0228 (6) | 0.0174 (7) | 0.0186 (6) | 0.0025 (5) | 0.0042 (5) | −0.0014 (5) |
C5 | 0.0236 (6) | 0.0194 (8) | 0.0205 (6) | −0.0002 (5) | 0.0047 (5) | 0.0014 (5) |
C6 | 0.0200 (6) | 0.0283 (8) | 0.0183 (6) | −0.0011 (6) | 0.0054 (5) | −0.0003 (5) |
C7 | 0.0214 (6) | 0.0220 (8) | 0.0237 (6) | 0.0017 (6) | 0.0068 (5) | −0.0052 (5) |
C8 | 0.0200 (6) | 0.0163 (7) | 0.0226 (6) | −0.0005 (5) | 0.0019 (5) | −0.0009 (5) |
C9 | 0.0182 (5) | 0.0181 (7) | 0.0180 (6) | 0.0009 (5) | 0.0028 (5) | −0.0007 (5) |
C10 | 0.0215 (6) | 0.0150 (7) | 0.0197 (6) | −0.0003 (5) | 0.0031 (5) | 0.0006 (5) |
O10 | 0.0375 (5) | 0.0169 (5) | 0.0281 (5) | 0.0067 (4) | 0.0192 (4) | 0.0034 (4) |
C11 | 0.0372 (8) | 0.0409 (10) | 0.0374 (8) | −0.0043 (8) | 0.0230 (7) | −0.0102 (8) |
C12 | 0.0338 (7) | 0.0206 (9) | 0.0272 (7) | 0.0058 (6) | 0.0151 (6) | −0.0008 (6) |
C13 | 0.0232 (6) | 0.0138 (7) | 0.0202 (6) | 0.0016 (5) | 0.0070 (5) | −0.0002 (5) |
C14 | 0.0250 (6) | 0.0249 (8) | 0.0246 (6) | 0.0031 (6) | 0.0055 (5) | 0.0026 (5) |
C15 | 0.0362 (7) | 0.0275 (8) | 0.0224 (6) | 0.0063 (6) | 0.0070 (6) | 0.0053 (6) |
C16 | 0.0424 (8) | 0.0178 (8) | 0.0262 (6) | −0.0018 (6) | 0.0181 (6) | −0.0001 (6) |
C17 | 0.0283 (7) | 0.0287 (8) | 0.0300 (7) | −0.0073 (6) | 0.0119 (6) | −0.0029 (6) |
C18 | 0.0242 (6) | 0.0269 (8) | 0.0214 (6) | −0.0014 (6) | 0.0040 (5) | 0.0005 (5) |
O1—C8 | 1.3905 (16) | O10—C12 | 1.4447 (15) |
O1—C2 | 1.4024 (14) | C11—H111 | 1.023 (16) |
C2—O2 | 1.1993 (15) | C11—H112 | 1.015 (17) |
C2—C3 | 1.4644 (18) | C11—H113 | 1.005 (17) |
C3—C10 | 1.3550 (16) | C12—H121 | 0.987 (14) |
C3—C9 | 1.4605 (17) | C12—H122 | 1.005 (14) |
O6—C6 | 1.3733 (14) | C12—H123 | 1.000 (18) |
O6—C11 | 1.4273 (18) | C13—C18 | 1.3881 (16) |
C4—C9 | 1.3883 (18) | C13—C14 | 1.3893 (17) |
C4—C5 | 1.3885 (16) | C14—C15 | 1.3878 (19) |
C4—H4 | 0.985 (14) | C14—H14 | 1.007 (14) |
C5—C6 | 1.4007 (18) | C15—C16 | 1.3803 (19) |
C5—H5 | 1.062 (15) | C15—H15 | 1.017 (14) |
C6—C7 | 1.3860 (19) | C16—C17 | 1.3829 (19) |
C7—C8 | 1.3781 (16) | C16—H16 | 0.980 (15) |
C7—H7 | 0.960 (15) | C17—C18 | 1.3885 (18) |
C8—C9 | 1.3857 (17) | C17—H17 | 0.999 (14) |
C10—O10 | 1.3426 (15) | C18—H18 | 0.998 (14) |
C10—C13 | 1.4879 (17) | ||
C8—O1—C2 | 107.67 (9) | O6—C11—H111 | 104.3 (10) |
O2—C2—O1 | 119.04 (11) | O6—C11—H112 | 110.9 (9) |
O2—C2—C3 | 133.17 (11) | H111—C11—H112 | 107.6 (12) |
O1—C2—C3 | 107.77 (10) | O6—C11—H113 | 110.6 (9) |
C10—C3—C9 | 129.73 (12) | H111—C11—H113 | 111.5 (12) |
C10—C3—C2 | 123.86 (11) | H112—C11—H113 | 111.7 (14) |
C9—C3—C2 | 106.33 (10) | O10—C12—H121 | 108.7 (8) |
C6—O6—C11 | 116.80 (11) | O10—C12—H122 | 110.0 (8) |
C9—C4—C5 | 118.87 (11) | H121—C12—H122 | 111.5 (11) |
C9—C4—H4 | 121.5 (8) | O10—C12—H123 | 107.0 (8) |
C5—C4—H4 | 119.6 (8) | H121—C12—H123 | 108.1 (12) |
C4—C5—C6 | 120.59 (12) | H122—C12—H123 | 111.4 (12) |
C4—C5—H5 | 121.3 (7) | C18—C13—C14 | 119.70 (11) |
C6—C5—H5 | 118.1 (7) | C18—C13—C10 | 120.52 (11) |
O6—C6—C7 | 123.42 (11) | C14—C13—C10 | 119.77 (10) |
O6—C6—C5 | 115.00 (12) | C15—C14—C13 | 120.15 (12) |
C7—C6—C5 | 121.57 (11) | C15—C14—H14 | 119.0 (9) |
C8—C7—C6 | 115.81 (11) | C13—C14—H14 | 120.7 (8) |
C8—C7—H7 | 120.1 (8) | C16—C15—C14 | 119.90 (12) |
C6—C7—H7 | 124.0 (8) | C16—C15—H15 | 120.5 (8) |
C7—C8—C9 | 124.66 (12) | C14—C15—H15 | 119.6 (8) |
C7—C8—O1 | 123.08 (11) | C15—C16—C17 | 120.24 (12) |
C9—C8—O1 | 112.21 (10) | C15—C16—H16 | 119.5 (8) |
C8—C9—C4 | 118.49 (11) | C17—C16—H16 | 120.2 (8) |
C8—C9—C3 | 105.97 (11) | C16—C17—C18 | 120.10 (12) |
C4—C9—C3 | 135.32 (11) | C16—C17—H17 | 119.7 (9) |
O10—C10—C3 | 115.77 (11) | C18—C17—H17 | 120.1 (9) |
O10—C10—C13 | 120.71 (10) | C13—C18—C17 | 119.89 (12) |
C3—C10—C13 | 123.52 (12) | C13—C18—H18 | 119.1 (8) |
C10—O10—C12 | 120.41 (10) | C17—C18—H18 | 120.9 (8) |
C8—O1—C2—O2 | 179.39 (11) | C10—C3—C9—C8 | 176.49 (12) |
C8—O1—C2—C3 | −2.05 (12) | C2—C3—C9—C8 | −0.32 (13) |
O2—C2—C3—C10 | 2.7 (2) | C10—C3—C9—C4 | −9.2 (2) |
O1—C2—C3—C10 | −175.58 (10) | C2—C3—C9—C4 | 174.00 (13) |
O2—C2—C3—C9 | 179.74 (13) | C9—C3—C10—O10 | −4.39 (18) |
O1—C2—C3—C9 | 1.47 (13) | C2—C3—C10—O10 | 171.92 (11) |
C9—C4—C5—C6 | 0.03 (17) | C9—C3—C10—C13 | 176.25 (11) |
C11—O6—C6—C7 | 0.32 (17) | C2—C3—C10—C13 | −7.45 (18) |
C11—O6—C6—C5 | −178.61 (12) | C3—C10—O10—C12 | 177.00 (11) |
C4—C5—C6—O6 | 178.80 (11) | C13—C10—O10—C12 | −3.62 (17) |
C4—C5—C6—C7 | −0.16 (18) | O10—C10—C13—C18 | −72.54 (16) |
O6—C6—C7—C8 | −178.22 (11) | C3—C10—C13—C18 | 106.79 (14) |
C5—C6—C7—C8 | 0.65 (17) | O10—C10—C13—C14 | 108.86 (14) |
C6—C7—C8—C9 | −1.09 (18) | C3—C10—C13—C14 | −71.80 (17) |
C6—C7—C8—O1 | 176.08 (11) | C18—C13—C14—C15 | −1.2 (2) |
C2—O1—C8—C7 | −175.54 (11) | C10—C13—C14—C15 | 177.39 (13) |
C2—O1—C8—C9 | 1.94 (12) | C13—C14—C15—C16 | 0.0 (2) |
C7—C8—C9—C4 | 1.00 (18) | C14—C15—C16—C17 | 1.0 (2) |
O1—C8—C9—C4 | −176.44 (10) | C15—C16—C17—C18 | −0.6 (2) |
C7—C8—C9—C3 | 176.45 (11) | C14—C13—C18—C17 | 1.6 (2) |
O1—C8—C9—C3 | −0.98 (13) | C10—C13—C18—C17 | −177.04 (12) |
C5—C4—C9—C8 | −0.42 (17) | C16—C17—C18—C13 | −0.6 (2) |
C5—C4—C9—C3 | −174.20 (12) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O2i | 0.985 (14) | 2.480 (14) | 3.4454 (16) | 166.6 (10) |
C4—H4···O10 | 0.985 (14) | 2.582 (13) | 3.0598 (15) | 109.9 (10) |
C11—H112···O6ii | 1.016 (18) | 2.47 (2) | 3.460 (2) | 163.7 (15) |
C12—H123···O2i | 1.00 (2) | 2.547 (17) | 3.2606 (18) | 128.0 (12) |
Symmetry codes: (i) x, y−1, z; (ii) −x, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C17H14O4 |
Mr | 282.28 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 10.5235 (8), 7.1136 (3), 18.2587 (13) |
β (°) | 100.632 (9) |
V (Å3) | 1343.38 (15) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.54 × 0.35 × 0.06 |
Data collection | |
Diffractometer | STOE IPDS diffractometer |
Absorption correction | Numerical (Coppens et al., 1965) |
Tmin, Tmax | 0.948, 0.994 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13623, 3849, 2237 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.710 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.067, 1.01 |
No. of reflections | 3849 |
No. of parameters | 246 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.22, −0.19 |
Computer programs: IPDS Software (Stoe & Cie, 1999), IPDS Software, IPDS (Stoe & Cie, 1999), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1990) and PLUTON (Spek, 1991), SHELXL97.
O1—C8 | 1.3905 (16) | C4—C5 | 1.3885 (16) |
O1—C2 | 1.4024 (14) | C5—C6 | 1.4007 (18) |
C2—O2 | 1.1993 (15) | C6—C7 | 1.3860 (19) |
C2—C3 | 1.4644 (18) | C7—C8 | 1.3781 (16) |
C3—C10 | 1.3550 (16) | C8—C9 | 1.3857 (17) |
C3—C9 | 1.4605 (17) | C10—O10 | 1.3426 (15) |
O6—C6 | 1.3733 (14) | C10—C13 | 1.4879 (17) |
O6—C11 | 1.4273 (18) | O10—C12 | 1.4447 (15) |
C4—C9 | 1.3883 (18) | ||
C8—O1—C2 | 107.67 (9) | C7—C6—C5 | 121.57 (11) |
O2—C2—O1 | 119.04 (11) | C8—C7—C6 | 115.81 (11) |
O2—C2—C3 | 133.17 (11) | C7—C8—C9 | 124.66 (12) |
O1—C2—C3 | 107.77 (10) | C7—C8—O1 | 123.08 (11) |
C10—C3—C9 | 129.73 (12) | C9—C8—O1 | 112.21 (10) |
C10—C3—C2 | 123.86 (11) | C8—C9—C4 | 118.49 (11) |
C9—C3—C2 | 106.33 (10) | C8—C9—C3 | 105.97 (11) |
C6—O6—C11 | 116.80 (11) | C4—C9—C3 | 135.32 (11) |
C9—C4—C5 | 118.87 (11) | O10—C10—C3 | 115.77 (11) |
C4—C5—C6 | 120.59 (12) | O10—C10—C13 | 120.71 (10) |
O6—C6—C7 | 123.42 (11) | C3—C10—C13 | 123.52 (12) |
O6—C6—C5 | 115.00 (12) | C10—O10—C12 | 120.41 (10) |
C9—C3—C10—C13 | 176.25 (11) | C3—C10—C13—C18 | 106.79 (14) |
C2—C3—C10—C13 | −7.45 (18) | O10—C10—C13—C14 | 108.86 (14) |
O10—C10—C13—C18 | −72.54 (16) | C3—C10—C13—C14 | −71.80 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O2i | 0.985 (14) | 2.480 (14) | 3.4454 (16) | 166.6 (10) |
C4—H4···O10 | 0.985 (14) | 2.582 (13) | 3.0598 (15) | 109.9 (10) |
C11—H112···O6ii | 1.016 (18) | 2.47 (2) | 3.460 (2) | 163.7 (15) |
C12—H123···O2i | 1.00 (2) | 2.547 (17) | 3.2606 (18) | 128.0 (12) |
Symmetry codes: (i) x, y−1, z; (ii) −x, y+1/2, −z+1/2. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Isoaurones [3-arylidenebenzofuran-2(3H)ones] are an uncommon class of flavonoid compound isomeric with aurones [2-arylidenebenzofuran-3(2H)-ones], some of which are naturally occurring, e.g. E-marginalin (Barbier, 1987). Like the aurones, isoaurones can exist in either the E– or the Z-form. This class of compound has been of synthetic interest over the years (Gripenberg & Juselius, 1954; Walter et al., 1966; Moriarty et al., 1984; Litinas & Stampelos, 1992; Rossi et al., 1995). In the course of our studies in the flavonoid field we have synthesized the unusual title isoaurone type enol ether compound, (II) (Burke & O'Sullivan, 1997) via lactonization and subsequent dehydration of (2R,3R)-2-hydroxy-2-(2-hydroxy-4-methoxyphenyl)-3-methoxy-3-phenylpropan-1-oic acid, (I). \scheme
We have determined on the basis of the following X-ray crystallographic analysis that the novel isoaurone compound, (II), has the E-configuration. This result clearly indicates that the glycolic acid product, (I), possesses the (2R,3R) [or (2S,3S)] configuration, if the dehydration step leading to the isoaurone (II) occurs by the expected concerted anti-periplanar E2 elimination reaction at (I). In the original paper (Brady et al., 1989) reporting the synthesis of (I) as the result of a benzilic acid rearrangement on 1-(2-hydroxy-4-methoxyphenyl)-3-methoxy-3-phenylpropan-1,2-dione, compound (I) was assigned the (2R,3S)-configuration on the basis of a mechanistic postulate. At the present moment the mechanism of this reaction is being re-evaluated. In the original paper (Brady et al., 1989) the diagram clearly shows that the glycolic acid product had the (2R,3S)-configuration, but it was inadvertently named (2R,3R) in the text. This error was carried over into our subsequent paper (Burke et al., 1997).
The furanone ring of the title compound, (II), which is essentially planar, is fused to a methoxybenzene ring system. Both ring systems are approximately coplanar, the angle between the furanone moiety and the fused benzene ring being 175.7 (1)°. Selected bond lengths and angles in Table 1 show that the benzene ring C4—C9 has a remarkable amount of angle strain arising from the ring fusion. The internal bond angles [C7 115.8 (1), C8 124.7 (1), C9 118.5 (1) and C4 118.9 (1)°] are all somewhat different from 120.0°, whereas the vinylic phenyl ring has internal angles between 119.7 (1) and 120.2 (1)°. In accordance with an earlier nuclear Overhauser effect experiment, the present X-ray experiment shows the large distance of 3.703 (16) Å between H4 and the C12 methyl of the vinylic methoxyl group (Fig. 1). It is also worth observing that the vinylic phenyl group is rotated out of the plane with the benzofuranone moiety by 78.8 (1)°. This had already been predicted using Dreiding molecular models. Some prominent torsion angles are also shown in Table 1.
The molecules in the crystal of (II) are packed together via intermolecular C—H···O interactions and stacking between the benzofuranone ring systems. If we consider the intramolecular hydrogen bond C4—H4···O10 and the intermolecular hydrogen bond C4—H4···O2, then H4 has a bifurcated donor function. With the intermolecular C12—H123···O2 bond the keto oxygen O2 is a bifurcated acceptor. The above mentioned hydrogen bonds form discrete layers along b. The view along the b axis (Fig. 2) shows that these layers are connected along the c direction via another intermolecular hydrogen bond, C11—H112···O6, where the methoxy H atom acts as a donor. Details of the hydrogen bonding system are given in Table 2. Furthermore, stacking of the benzofuranone moieties is also displayed in Fig. 2. The stacking follows the [201] direction; the distance between the centres of gravity of the rings is 3.672 (1) Å.