Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104020712/sk1758sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104020712/sk1758Isup2.hkl |
CCDC reference: 254952
To acetate (I) (10 mmol) melted in a flask, trimethyl phosphite (12 mmol) was added dropwise at 383–388 K. After 30 min of heating, excess phosphite was removed by distillation, and the resulting yellow oil was applied on a silica gel column, which was then eluted with a mixture of chloroform-acetone (5:1, v/v). The product was purified by crystallization from acetone (yield 9%) Spectroscopic analysis: absorption (diethyl ether): Rf = 0.86; IR (KBr, ν, cm−1): 1764.1, 1658.8 (C═O), 1620 (C═C), 1034 (C—O—C); 1H NMR (CDCl3, δ, p.p.m.): 2.22 (s, 3H, CH3), 6.48 (s, 1H, CH), 6.62 (s, 1H, CH), 7.42–7.58 (m, 9H, aromatic); 13C NMR (75.5 MHz, CDCl3, δ, p.p.m.): 20.54 (–C—CH3), 74.43 (CH), 76.59 (CH), 123.98, 128.08, 131.16, 146.22, 170.39 (C═O), 189.82 (C═O); EIMS, m/z (%): 295 (100, M+ +1), 245 (16).
All H atoms were positioned geometrically and refined with a riding model; for phenyl H atoms, C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C); for methyl H atoms, C—H = 0.96° and Uiso(H) = 1.5Ueq (C). The H atoms of the methyl group at C30 showed orientational disorder and were modelled with alternative positions occupied by 21 (1)%. Please clarify − 0.20 (2) in CIF table.
Data collection: WIN-EXPOSE in X-AREA (Stoe, 2000); cell refinement: WIN-CELL in X-AREA; data reduction: WIN-INTEGRATE in X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1998); software used to prepare material for publication: PARST97 (Nardelli, 1996).
C18H14O4 | F(000) = 616 |
Mr = 294.29 | Dx = 1.343 Mg m−3 |
Monoclinic, P21/c | Melting point = 304–305 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 6.8750 (6) Å | Cell parameters from 15217 reflections |
b = 25.3741 (17) Å | θ = 1.6–26.2° |
c = 8.3964 (8) Å | µ = 0.10 mm−1 |
β = 96.303 (8)° | T = 193 K |
V = 1455.9 (2) Å3 | Block, colourless |
Z = 4 | 0.5 × 0.24 × 0.2 mm |
Stoe IPDS II diffractometer | 2206 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.087 |
Graphite monochromator | θmax = 26.2°, θmin = 1.6° |
Detector resolution: 150 pixels mm-1 | h = −8→8 |
ϕ scans | k = −30→31 |
15217 measured reflections | l = −10→10 |
2926 independent reflections |
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) = 0.118 | w = 1/[σ2(Fo2) + (0.0763P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.00 | (Δ/σ)max < 0.001 |
2926 reflections | Δρmax = 0.19 e Å−3 |
202 parameters | Δρmin = −0.18 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.059 (7) |
C18H14O4 | V = 1455.9 (2) Å3 |
Mr = 294.29 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.8750 (6) Å | µ = 0.10 mm−1 |
b = 25.3741 (17) Å | T = 193 K |
c = 8.3964 (8) Å | 0.5 × 0.24 × 0.2 mm |
β = 96.303 (8)° |
Stoe IPDS II diffractometer | 2206 reflections with I > 2σ(I) |
15217 measured reflections | Rint = 0.087 |
2926 independent reflections |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.118 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.19 e Å−3 |
2926 reflections | Δρmin = −0.18 e Å−3 |
202 parameters |
Experimental. The MS data were obtained on a Finnigan Matt mass spectrometer (100 eV ionization energy) with isobutane as reagent. UV/VIS spectra were obtained at 800–400 nm on a Lambda 19 Perkin-Elmer instrument. Satisfactory elemental analysis (± 0.4% of calculated values) were obtained using a Perkin Elmer PE 2400 CHNS analyser. |
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 | Occ. (<1) | |
O1 | 0.32755 (14) | 0.05141 (4) | 0.70955 (11) | 0.0409 (3) | |
O4 | 0.19011 (15) | −0.05977 (4) | 1.02986 (11) | 0.0468 (3) | |
O28 | 0.39522 (15) | 0.12629 (4) | 1.06871 (11) | 0.0434 (3) | |
O29 | 0.58368 (16) | 0.19774 (4) | 1.04834 (13) | 0.0544 (3) | |
C2 | 0.3266 (2) | 0.06268 (5) | 0.86765 (15) | 0.0382 (3) | |
C3 | 0.2782 (2) | 0.02777 (6) | 0.97622 (16) | 0.0402 (3) | |
C4 | 0.2212 (2) | −0.02541 (6) | 0.93165 (16) | 0.0401 (3) | |
C5 | 0.1308 (2) | −0.08337 (6) | 0.69206 (18) | 0.0466 (4) | |
C6 | 0.1177 (2) | −0.09178 (6) | 0.52962 (18) | 0.0492 (4) | |
C7 | 0.1818 (2) | −0.05319 (6) | 0.42925 (17) | 0.0480 (4) | |
C8 | 0.2535 (2) | −0.00584 (6) | 0.49045 (16) | 0.0444 (3) | |
C9 | 0.2612 (2) | 0.00269 (5) | 0.65502 (16) | 0.0398 (3) | |
C10 | 0.2041 (2) | −0.03573 (6) | 0.75852 (16) | 0.0406 (3) | |
C21 | 0.3880 (2) | 0.11900 (5) | 0.89722 (15) | 0.0402 (3) | |
C22 | 0.2443 (2) | 0.15729 (5) | 0.80935 (16) | 0.0384 (3) | |
C23 | 0.3011 (2) | 0.18872 (6) | 0.68748 (16) | 0.0423 (3) | |
C24 | 0.1694 (2) | 0.22378 (6) | 0.60799 (17) | 0.0457 (4) | |
C25 | −0.0182 (2) | 0.22833 (6) | 0.65152 (17) | 0.0452 (4) | |
C26 | −0.0755 (2) | 0.19683 (6) | 0.77386 (17) | 0.0438 (3) | |
C27 | 0.0545 (2) | 0.16113 (5) | 0.85138 (16) | 0.0412 (3) | |
C29 | 0.4964 (2) | 0.16907 (6) | 1.12943 (17) | 0.0452 (4) | |
C30 | 0.4775 (3) | 0.17515 (7) | 1.30329 (18) | 0.0551 (4) | |
H3 | 0.2814 | 0.0380 | 1.0828 | 0.048* | |
H5 | 0.0905 | −0.1096 | 0.7587 | 0.056* | |
H6 | 0.0661 | −0.1232 | 0.4866 | 0.059* | |
H7 | 0.1761 | −0.0595 | 0.3197 | 0.058* | |
H8 | 0.2959 | 0.0199 | 0.4234 | 0.053* | |
H27 | 0.0150 | 0.1397 | 0.9317 | 0.049* | |
H21 | 0.5186 | 0.1245 | 0.8635 | 0.048* | |
H23 | 0.4278 | 0.1863 | 0.6590 | 0.051* | |
H24 | 0.2073 | 0.2443 | 0.5250 | 0.055* | |
H25 | −0.1055 | 0.2523 | 0.5993 | 0.054* | |
H26 | −0.2014 | 0.1998 | 0.8036 | 0.053* | |
H30A | 0.3801 | 0.1512 | 1.3337 | 0.083* | 0.20 (2) |
H30B | 0.4394 | 0.2107 | 1.3244 | 0.083* | 0.20 (2) |
H30C | 0.6009 | 0.1676 | 1.3640 | 0.083* | 0.20 (2) |
H30D | 0.5668 | 0.2018 | 1.3477 | 0.083* | 0.80 (2) |
H30E | 0.5075 | 0.1423 | 1.3570 | 0.083* | 0.80 (2) |
H30F | 0.3460 | 0.1854 | 1.3174 | 0.083* | 0.80 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0480 (6) | 0.0426 (5) | 0.0325 (5) | −0.0022 (4) | 0.0062 (4) | −0.0004 (4) |
O28 | 0.0524 (6) | 0.0438 (6) | 0.0334 (5) | −0.0029 (4) | 0.0019 (4) | −0.0010 (4) |
C2 | 0.0389 (7) | 0.0437 (8) | 0.0318 (6) | 0.0024 (5) | 0.0030 (5) | −0.0014 (5) |
O4 | 0.0553 (6) | 0.0458 (6) | 0.0394 (5) | −0.0059 (5) | 0.0058 (4) | 0.0050 (4) |
C27 | 0.0462 (8) | 0.0424 (8) | 0.0354 (7) | −0.0046 (6) | 0.0064 (6) | −0.0020 (5) |
C4 | 0.0385 (7) | 0.0435 (8) | 0.0386 (7) | 0.0017 (6) | 0.0053 (6) | 0.0019 (6) |
C9 | 0.0397 (7) | 0.0418 (7) | 0.0379 (7) | 0.0027 (6) | 0.0040 (6) | −0.0022 (6) |
C22 | 0.0437 (7) | 0.0375 (7) | 0.0339 (6) | −0.0020 (6) | 0.0032 (6) | −0.0031 (5) |
C26 | 0.0418 (8) | 0.0477 (8) | 0.0420 (7) | 0.0008 (6) | 0.0052 (6) | −0.0060 (6) |
C8 | 0.0456 (8) | 0.0528 (8) | 0.0351 (7) | 0.0034 (7) | 0.0056 (6) | 0.0003 (6) |
C21 | 0.0448 (7) | 0.0437 (7) | 0.0320 (6) | −0.0008 (6) | 0.0043 (5) | −0.0007 (5) |
C23 | 0.0429 (7) | 0.0448 (8) | 0.0398 (7) | −0.0005 (6) | 0.0068 (6) | 0.0011 (6) |
O29 | 0.0542 (6) | 0.0560 (6) | 0.0532 (6) | −0.0111 (5) | 0.0074 (5) | −0.0080 (5) |
C5 | 0.0512 (8) | 0.0434 (8) | 0.0443 (8) | 0.0015 (6) | 0.0017 (6) | 0.0001 (6) |
C10 | 0.0404 (7) | 0.0440 (8) | 0.0372 (7) | 0.0033 (6) | 0.0027 (6) | −0.0003 (6) |
C3 | 0.0443 (8) | 0.0437 (8) | 0.0325 (6) | 0.0007 (6) | 0.0034 (6) | 0.0000 (5) |
C25 | 0.0473 (8) | 0.0427 (8) | 0.0446 (8) | 0.0031 (6) | 0.0002 (6) | −0.0028 (6) |
C7 | 0.0490 (8) | 0.0561 (9) | 0.0383 (7) | 0.0083 (7) | 0.0025 (6) | −0.0066 (7) |
C6 | 0.0546 (9) | 0.0457 (8) | 0.0460 (8) | 0.0015 (7) | −0.0014 (7) | −0.0077 (7) |
C29 | 0.0454 (8) | 0.0454 (8) | 0.0437 (8) | 0.0019 (6) | −0.0009 (6) | −0.0042 (6) |
C30 | 0.0674 (10) | 0.0560 (9) | 0.0404 (8) | 0.0033 (8) | −0.0001 (7) | −0.0067 (7) |
C24 | 0.0540 (9) | 0.0423 (8) | 0.0413 (7) | −0.0009 (6) | 0.0072 (6) | 0.0052 (6) |
O1—C2 | 1.3586 (16) | C23—C24 | 1.387 (2) |
O1—C9 | 1.3784 (16) | C23—H23 | 0.9300 |
O28—C29 | 1.3579 (18) | O29—C29 | 1.2012 (19) |
O28—C21 | 1.4472 (16) | C5—C6 | 1.374 (2) |
C2—C3 | 1.3391 (19) | C5—C10 | 1.402 (2) |
C2—C21 | 1.5030 (19) | C5—H5 | 0.9300 |
O4—C4 | 1.2348 (17) | C3—H3 | 0.9300 |
C27—C26 | 1.384 (2) | C25—C24 | 1.383 (2) |
C27—C22 | 1.392 (2) | C25—H25 | 0.9300 |
C27—H27 | 0.9300 | C7—C6 | 1.395 (2) |
C4—C3 | 1.443 (2) | C7—H7 | 0.9300 |
C4—C10 | 1.4690 (19) | C6—H6 | 0.9300 |
C9—C10 | 1.391 (2) | C29—C30 | 1.488 (2) |
C9—C8 | 1.3938 (19) | C30—H30A | 0.9600 |
C22—C23 | 1.3869 (19) | C30—H30B | 0.9600 |
C22—C21 | 1.5181 (19) | C30—H30C | 0.9600 |
C26—C25 | 1.392 (2) | C30—H30D | 0.9600 |
C26—H26 | 0.9300 | C30—H30E | 0.9600 |
C8—C7 | 1.376 (2) | C30—H30F | 0.9600 |
C8—H8 | 0.9300 | C24—H24 | 0.9300 |
C21—H21 | 0.9800 | ||
C2—O1—C9 | 118.46 (11) | C2—C3—H3 | 119.2 |
C29—O28—C21 | 115.84 (11) | C4—C3—H3 | 119.2 |
C3—C2—O1 | 123.64 (13) | C24—C25—C26 | 119.65 (13) |
C3—C2—C21 | 127.07 (12) | C24—C25—H25 | 120.2 |
O1—C2—C21 | 109.28 (11) | C26—C25—H25 | 120.2 |
C26—C27—C22 | 120.10 (13) | C8—C7—C6 | 120.74 (14) |
C26—C27—H27 | 120.0 | C8—C7—H7 | 119.6 |
C22—C27—H27 | 120.0 | C6—C7—H7 | 119.6 |
O4—C4—C3 | 123.30 (12) | C5—C6—C7 | 120.02 (14) |
O4—C4—C10 | 122.28 (13) | C5—C6—H6 | 120.0 |
C3—C4—C10 | 114.41 (12) | C7—C6—H6 | 120.0 |
O1—C9—C10 | 121.79 (12) | O29—C29—O28 | 122.58 (13) |
O1—C9—C8 | 116.33 (12) | O29—C29—C30 | 126.59 (14) |
C10—C9—C8 | 121.88 (13) | O28—C29—C30 | 110.81 (14) |
C23—C22—C27 | 119.64 (13) | C29—C30—H30A | 109.5 |
C23—C22—C21 | 120.38 (13) | C29—C30—H30B | 109.5 |
C27—C22—C21 | 119.98 (12) | H30A—C30—H30B | 109.5 |
C27—C26—C25 | 120.15 (13) | C29—C30—H30C | 109.5 |
C27—C26—H26 | 119.9 | H30A—C30—H30C | 109.5 |
C25—C26—H26 | 119.9 | H30B—C30—H30C | 109.5 |
C7—C8—C9 | 118.59 (14) | C29—C30—H30D | 109.5 |
C7—C8—H8 | 120.7 | H30A—C30—H30D | 141.1 |
C9—C8—H8 | 120.7 | H30B—C30—H30D | 56.3 |
O28—C21—C2 | 105.32 (11) | H30C—C30—H30D | 56.3 |
O28—C21—C22 | 110.55 (11) | C29—C30—H30E | 109.5 |
C2—C21—C22 | 111.85 (11) | H30A—C30—H30E | 56.3 |
O28—C21—H21 | 109.7 | H30B—C30—H30E | 141.1 |
C2—C21—H21 | 109.7 | H30C—C30—H30E | 56.3 |
C22—C21—H21 | 109.7 | H30D—C30—H30E | 109.5 |
C22—C23—C24 | 120.12 (14) | C29—C30—H30F | 109.5 |
C22—C23—H23 | 119.9 | H30A—C30—H30F | 56.3 |
C24—C23—H23 | 119.9 | H30B—C30—H30F | 56.3 |
C6—C5—C10 | 120.71 (15) | H30C—C30—H30F | 141.1 |
C6—C5—H5 | 119.6 | H30D—C30—H30F | 109.5 |
C10—C5—H5 | 119.6 | H30E—C30—H30F | 109.5 |
C9—C10—C5 | 118.00 (13) | C25—C24—C23 | 120.32 (14) |
C9—C10—C4 | 119.74 (13) | C25—C24—H24 | 119.8 |
C5—C10—C4 | 122.26 (13) | C23—C24—H24 | 119.8 |
C2—C3—C4 | 121.52 (12) |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7···O4i | 0.93 | 2.45 | 3.364 (1) | 169 |
C25—H25···O29ii | 0.93 | 2.48 | 3.353 (1) | 156 |
C27—H27···O4iii | 0.93 | 2.51 | 3.286 (1) | 141 |
C6—H6···CgCiv | 0.93 | 2.73 | 3.615 (1) | 160 |
Symmetry codes: (i) x, y, z−1; (ii) x−1, −y+1/2, z−1/2; (iii) −x, −y, −z+2; (iv) −x, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C18H14O4 |
Mr | 294.29 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 193 |
a, b, c (Å) | 6.8750 (6), 25.3741 (17), 8.3964 (8) |
β (°) | 96.303 (8) |
V (Å3) | 1455.9 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.5 × 0.24 × 0.2 |
Data collection | |
Diffractometer | Stoe IPDS II diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15217, 2926, 2206 |
Rint | 0.087 |
(sin θ/λ)max (Å−1) | 0.621 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.118, 1.00 |
No. of reflections | 2926 |
No. of parameters | 202 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.18 |
Computer programs: WIN-EXPOSE in X-AREA (Stoe, 2000), WIN-CELL in X-AREA, WIN-INTEGRATE in X-AREA, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1998), PARST97 (Nardelli, 1996).
O1—C2 | 1.3586 (16) | C9—C8 | 1.3938 (19) |
O1—C9 | 1.3784 (16) | C22—C23 | 1.3869 (19) |
O28—C29 | 1.3579 (18) | C22—C21 | 1.5181 (19) |
O28—C21 | 1.4472 (16) | C26—C25 | 1.392 (2) |
C2—C3 | 1.3391 (19) | C8—C7 | 1.376 (2) |
C2—C21 | 1.5030 (19) | C23—C24 | 1.387 (2) |
O4—C4 | 1.2348 (17) | O29—C29 | 1.2012 (19) |
C27—C26 | 1.384 (2) | C5—C6 | 1.374 (2) |
C27—C22 | 1.392 (2) | C5—C10 | 1.402 (2) |
C4—C3 | 1.443 (2) | C25—C24 | 1.383 (2) |
C4—C10 | 1.4690 (19) | C7—C6 | 1.395 (2) |
C9—C10 | 1.391 (2) | C29—C30 | 1.488 (2) |
C2—O1—C9 | 118.46 (11) | O1—C9—C8 | 116.33 (12) |
C29—O28—C21 | 115.84 (11) | O28—C21—C2 | 105.32 (11) |
C3—C2—O1 | 123.64 (13) | O28—C21—C22 | 110.55 (11) |
O1—C2—C21 | 109.28 (11) | O29—C29—O28 | 122.58 (13) |
O4—C4—C3 | 123.30 (12) | O29—C29—C30 | 126.59 (14) |
O4—C4—C10 | 122.28 (13) | O28—C29—C30 | 110.81 (14) |
O1—C9—C10 | 121.79 (12) |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7···O4i | 0.93 | 2.45 | 3.364 (1) | 169 |
C25—H25···O29ii | 0.93 | 2.48 | 3.353 (1) | 156 |
C27—H27···O4iii | 0.93 | 2.51 | 3.286 (1) | 141 |
C6—H6···CgCiv | 0.93 | 2.73 | 3.615 (1) | 160 |
Symmetry codes: (i) x, y, z−1; (ii) x−1, −y+1/2, z−1/2; (iii) −x, −y, −z+2; (iv) −x, −y, −z+1. |
Chromone and coumarin derivatives exhibit a wide spectrum of biological activity, including spasmolytic, antiarrhythmic, cardiothonic, antiviral, and anticancer and alkylating properties (Gabor, 1988; Valenti et al., 1993, 1998). In general, alkylating agents are the first class of cytostatics used for therapy (Zon, 1982). Under in vivo conditions, these agents alkylate nucleophilic centres of nucleobases and amino acids, resulting in either cleavage or cross-linking of double-stranded DNA molecules or proteins. Such cleavage causes damage of DNA, while covalent cross-links prevent unwinding of nucleic acids, which is functionally important in replication and transcription processes (Lindermann & Harbers, 1980).
In the multistep reaction of α-bromoketone, (I), with trimethyl phosphate, we obtained two products of the Perkov- and Arbuzov-type (Budzisz et al., 2002). This compound cyclizes to form a mixture of diastereoisomers which, subsequently, either lose dimethyl phosphate to give the Wittig-type (March, 1992) product, (III), or undergo 1,2-trans-elimination of water on the column to give the 3-phosphonic chromone derivative, (II). \sch
The alkylating properties of the test derivatives can be determined by an in vitro Preussmann test (Preussmann et al., 1969). This test permits the estimation of the direct ability of the compound to alkylate the model target molecule, 4-(4-nitrobenzyl)pyridine, and it provides a useful indication of alkylation potential for nucleophilic centres of aminoacids and nucleobases. However, due to its simplicity, the Preussmann test does not allow the determination of the mode of DNA alkylation. The title compound, (III), possesses very high (+++) alkylating activity (Budzisz et al., 2002). Against this background, and in order to obtain detailed information about the molecular structure of the title compund in the solid state, an X-ray structure investigation was carried out and the results are presented here.
Fig. 1 shows a perspective view of the molecule of (III) with the atom-numbering scheme. Most of the bond lengths and angles are comparable with expected values (Allen et al., 1987). The molecule of (III) consists of two condensed rings, a benzene and a pyran ring. The phenylmethylacetate group is attached in position 2. The two fused rings are almost coplanar; the dihedral angle between the best planes of rings A (C5—C10) and B (O1/C2—C4/C10/C9) is 3.61 (5)°. The best plane of ring B is nearly planar; the deviations of atoms O1, C2, C3, C4, C10 and C9 from the weighted least-squares plane are −0.023, 0.029, 0.017, −0.045, 0.030 and 0.014 Å, respectively, and this is typical for 255 structures with the benzopyran moiety found in the Cambridge Structural Database (CSD, Version 5.25, November, 2003; Allen, 2002). The planarity of the benzopyran moiety is confirmation of the aromatic character of this system. Neverthertheless, a lengthening of the C4—C10 and C4—C3 bonds is observed, to 1.469 (2) and 1.443 (2) Å, respectively, and the angle of the C3—C4—C10 valence bond decreases to 114.4 (1)°. In contrast, the shortest bond length and the largest angle are observed for atom C2, viz. 1.339 (2) Å and 123.6 (1)°, respectively. The C10—C9—C8 and C9—C10—C5 angles are 121.9 (1) and 118.0 (1)°, respectively. Similar variations in the geometric parameters of the pyran ring in the benzopyran system have been reported previously (Rybarczyk-Pirek & Nawrot-Modranka, 2004; Thinagar et al., 2003). It is worth mentioning that a search of the CSD for structures containing the benzopyran fragment, (IV), revealed similar geometric parameters for 255 fragments. Mean values for the geometric parameters of the above analyzed fragment are: C4—C10 1.45 (2), C4—C3 1.44 (2) and C2—C3 1.35 (2) Å, and C10—C4—C3 115 (2), C3—C2—O1 122 (2), C8—C9—C10 122 (2) and C5—C10—C9 117 (2)°.
Benzene ring C (C22—C27) of (III) is almost perpendicular to both the benzopyran moiety and the methylacetate group. The dihedral angle between ring C and rings A and B is 86.49 (2)°, and the O1—C2—C21—C22 and C3—C2—C21—C22 torsion angles are 63.5 (2) and −116.7 (2)°, respectively, showing a +synclinal (+sc) orientation of ring C with respect to the benzopyran system. The C22—C21—O28—C29 torsion angle of −76.2 (2)° confirms it is perpendicular to the methylacetate group. The structural parameters for the above-mentioned group are consistent with those of 14 similar structures found in the CSD that have a methylacetate group.
In compound (III), the supramolecular aggregation is stabilized by a combination of π–π stacking interactions and weak C—H···O and C—H···π interactions. Aromatic π–π stacking interactions are formed between rings A and B. The distances between the ring centroids, CgA···CgAv and CgB···CgBvi, are 3.682 (1) and 4.228 (1) Å, respectively [CgA is the centroid of ring A and CgB is the centroid of ring B; symmetry codes: (v) −x, −y, 1 − z; (vi) 1 − x, −y, 2 − z]. The perpendicular distances are 3.298 (1) and 3.290 (1) Å for rings A and B, respectively.
An analysis of the hydrogen bonding in (III) shows many non-conventional C—H···O and C—H···π interactions. Atom C7 is involved in a weak C—H···O intermolecular interaction with atom O4(x, y, z − 1), so generating a C(7) chain motif (Bernstein et al., 1995). Atom O4(-x, −y, 2 − z) is also an acceptor for a weak C4—H4···O4 interaction, which produces an R22(16) motif centred at (0, 0, 1). Atom C25 acts as a donor in an intermolecular interaction [graph set C(9)] with atom O29(x − 1, 1/2 − y, z − 1/2). Weak Csp3—H···πarene interactions, for instance C6—H6···CgCvii [CgC is the centroid of ring C; symmetry code: (vii) −x, −y, 1 − z Can this be replaced with (v), as the symmetry operator is the same for both?] complete the range of intermolecular interactions.