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Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): o2228.
Published online 2009 August 22. doi:  10.1107/S1600536809032747
PMCID: PMC2970093

9-Eth­oxy-1,5,13-trimethyl-8,10-dioxa­tetra­cyclo­[7.7.1.02,7.011,16]hepta­deca-2,4,6,11,13,15-hexa­ene

Abstract

The reaction of ethyl acetoacetate with meta-cresol in an acidic ionic liquid yielded a complex mixture of condensation products. 4,7-Dimethyl­coumarin and the title compound, C20H22O3, were isolated. The title compound shows chemical but not crystallographic mirror symmetry. The two aromatic rings are inclined at an angle of 73.55 (6)°.

Related literature

For related structures, see: Klei et al. (1995 [triangle]); Vijayalakshmi et al. (2001 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o2228-scheme1.jpg

Experimental

Crystal data

  • C20H22O3
  • M r = 310.38
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2228-efi1.jpg
  • a = 14.3718 (6) Å
  • b = 11.6446 (5) Å
  • c = 10.2260 (4) Å
  • β = 96.901 (4)°
  • V = 1698.96 (12) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 90 K
  • 0.25 × 0.20 × 0.10 mm

Data collection

  • Oxford Diffraction Xcalibur diffractometer
  • Absorption correction: none
  • 9989 measured reflections
  • 2985 independent reflections
  • 1751 reflections with I > 2σ(I)
  • R int = 0.031

Refinement

  • R[F 2 > 2σ(F 2)] = 0.047
  • wR(F 2) = 0.126
  • S = 0.95
  • 2985 reflections
  • 252 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.27 e Å−3
  • Δρmin = −0.23 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 [triangle]); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 [triangle]); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809032747/bt2970sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809032747/bt2970Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Experimental

Anhydrous aluminium chloride (16.0 g, 60 mmol of Al2Cl6) and 1-n-butyl-3-methyl-imidazolium chloride (10.5 g, 60 mmol of [bmim]Cl) were mixed under dry nitrogen atmosphere. Ionic liquid ([bmim] Al2Cl7) was formed in the exothermic reaction of two solid substrates. The melt of meta-cresol (6.3 ml, 60 mmol) and ethyl acetoacetate (7.5 ml, 60 mmol) was dissolved in the ionic liquid and maintained at ambient temperature for 5 days. A yellow, viscous liquid was poured on ice and an opaque solution was extracted twice with methylene chloride. The organic solution was extracted with diluted sulfuric acid (25 ml of 3M H2SO4) and water to remove aluminium compounds. It was dried over anhydrous magnesium sulfate and adsorbed on silica gel (Kieselgel H, Fluka). The crude reaction mixture was chromatographed on the short column (5.5 by 15 cm) using benzene as the eluent. The first fraction, after evaporation and crystallization from n-hexane, gave title compound (I) (1.11 g, 12%) as colourless prisms, m.p. 146–153°C. Recrystallization from isooctane raised m.p. to 153–155°C, the crystals were suitable for X-ray diffraction studies. MS, m/z (int.): 310 (38, M+), 295 (100), 281 (5), 267 (78), 264 (5), 249 (7), 239 (8), 223 (11), 203 (27), 175 (26). FTIR (KBr): 3037 (aromatic protons); 2985, 2969, 2937, 2909 (aliphatic C–H stretching vibrations); 1623, 1580, 1506 (benzene ring stretching); 1271, 1157, 1127, 1090, 1050, 1008 (C–O–C stretching vibrations); 886, 814 (out of plane hydrogen wagging in aromatic rings). 1H-NMR (DMSO-d6): 7.26, d 3 J = 7.4 Hz, 2H and 6.70, d 3J = 7.4 Hz, 2H (vicinal aromatic protons); 6.63, s, 2H (isolated aromatic protons); 4.04, q, 3J = 6.7 Hz, 2H and 1.26, t, 3 J = 6.7 Hz, 3H (O-ethyl group); 2.21, s, 2H (methylene bridge); 2.16, s, 6H (methyl groups bound to aromatic rings); 1.76, s, 3H (methyl group). 13C-NMR (CDCl3): 151.8 (C4, C16); 137.8 (C6, C14); 127.5 (C9, C11); 123.8 (C8, C12); 122.6 (C7, C13); 117.1 (C5, C15); 112.1 (C2); 58.5 and 15.7 (O-ethyl group); 38.8 (methylene bridge); 34.8 (C10); 21.1 (methyl groups on aromatic rings). The next fraction provided 4,7-dimethyl-coumarin as white crystals (1.32 g, 12.6%); m.p. 135–136°C (n-hexane). From the last fraction small amounts of 1,2-dihydro-4,7-dimethyl-4-(4-hydroxy-2-methylphenyl)-coumarin (isomer 2) were isolated (m.p. 211–212°C).

Refinement

Methyl H-atoms were positioned geometrically and refined using a riding model allowed to rotate but not to tip with Uiso(H) = 1.5Ueq(C). The remaining H atoms were freely refined.

Figures

Fig. 1.
The molecular structure of the title compound showing 50% displacement ellipsoids (arbitrary spheres for the H atoms).

Crystal data

C20H22O3F(000) = 664
Mr = 310.38Dx = 1.213 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2985 reflections
a = 14.3718 (6) Åθ = 2.7–25.0°
b = 11.6446 (5) ŵ = 0.08 mm1
c = 10.2260 (4) ÅT = 90 K
β = 96.901 (4)°Plate, colourless
V = 1698.96 (12) Å30.25 × 0.20 × 0.10 mm
Z = 4

Data collection

Oxford Diffraction Xcalibur diffractometer1751 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.031
graphiteθmax = 25.0°, θmin = 2.7°
Detector resolution: 1024 x 1024 with blocks 2 x 2 pixels mm-1h = −17→17
ω scansk = −13→13
9989 measured reflectionsl = −12→6
2985 independent reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.047Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.126H atoms treated by a mixture of independent and constrained refinement
S = 0.95w = 1/[σ2(Fo2) + (0.0723P)2] where P = (Fo2 + 2Fc2)/3
2985 reflections(Δ/σ)max < 0.001
252 parametersΔρmax = 0.27 e Å3
0 restraintsΔρmin = −0.23 e Å3

Special details

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)

xyzUiso*/Ueq
C10.24961 (15)0.47696 (17)0.2890 (2)0.0235 (5)
O1A0.20501 (9)0.37104 (11)0.26845 (13)0.0263 (4)
C1B0.17179 (18)0.3422 (2)0.1307 (2)0.0317 (6)
C1C0.13069 (17)0.22326 (18)0.1300 (2)0.0379 (6)
H1C10.10890.20120.04110.057*
H1C20.07910.22260.18160.057*
H1C30.17780.17010.16680.057*
O20.33294 (10)0.47258 (12)0.22253 (13)0.0288 (4)
C30.40517 (14)0.55031 (17)0.26325 (19)0.0226 (5)
C40.48180 (15)0.55002 (18)0.1881 (2)0.0236 (5)
C50.55726 (14)0.62572 (17)0.21702 (19)0.0236 (5)
C5A0.64239 (15)0.62257 (19)0.1394 (2)0.0294 (5)
H510.62210.60320.04920.044*
H520.68620.56600.17710.044*
H530.67200.69660.14330.044*
C60.55384 (16)0.70296 (18)0.3227 (2)0.0271 (5)
C70.47795 (15)0.70088 (18)0.3991 (2)0.0253 (5)
C7A0.40231 (14)0.62393 (17)0.37198 (18)0.0222 (5)
C80.31708 (14)0.62109 (17)0.45321 (19)0.0218 (5)
C8A0.34643 (15)0.64395 (18)0.60163 (19)0.0276 (5)
H810.29230.63970.64800.041*
H820.37380.71900.61290.041*
H830.39140.58730.63600.041*
C9A0.24205 (14)0.70553 (17)0.38933 (19)0.0226 (5)
C90.23106 (15)0.81749 (18)0.4337 (2)0.0256 (5)
C100.16298 (15)0.89076 (19)0.3686 (2)0.0256 (5)
C110.10309 (14)0.85430 (17)0.2566 (2)0.0244 (5)
C11A0.03150 (16)0.93435 (19)0.1825 (2)0.0341 (6)
H111−0.02820.89650.16810.051*
H1120.05150.95430.09920.051*
H1130.02601.00270.23340.051*
C120.11309 (15)0.74147 (18)0.2120 (2)0.0240 (5)
C130.18201 (14)0.66987 (17)0.27796 (19)0.0225 (5)
O140.18724 (10)0.56098 (11)0.22264 (13)0.0272 (4)
C150.27228 (16)0.50062 (18)0.4352 (2)0.0240 (5)
H1B10.2258 (16)0.3455 (18)0.076 (2)0.043 (7)*
H1B20.1230 (15)0.4022 (18)0.094 (2)0.033 (6)*
H4A0.4837 (14)0.4925 (18)0.116 (2)0.028 (6)*
H6A0.6069 (14)0.7588 (18)0.3474 (19)0.025 (5)*
H7A0.4784 (14)0.7539 (18)0.472 (2)0.027 (6)*
H9A0.2729 (14)0.8461 (17)0.515 (2)0.028 (6)*
H10A0.1543 (14)0.9711 (18)0.403 (2)0.031 (6)*
H12A0.0748 (17)0.7141 (19)0.133 (2)0.044 (7)*
H15A0.3208 (15)0.4429 (19)0.477 (2)0.035 (6)*
H15B0.2132 (16)0.4963 (17)0.480 (2)0.032 (6)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0254 (12)0.0176 (11)0.0280 (11)−0.0014 (9)0.0055 (9)0.0029 (9)
O1A0.0305 (9)0.0197 (8)0.0285 (8)−0.0036 (7)0.0028 (7)−0.0012 (6)
C1B0.0363 (14)0.0266 (13)0.0319 (12)−0.0039 (11)0.0023 (11)−0.0039 (10)
C1C0.0399 (15)0.0277 (14)0.0451 (15)0.0006 (11)0.0005 (12)−0.0074 (11)
O20.0273 (8)0.0280 (9)0.0324 (8)−0.0055 (7)0.0085 (7)−0.0072 (7)
C30.0233 (12)0.0188 (11)0.0248 (11)0.0009 (9)−0.0014 (9)0.0015 (9)
C40.0259 (12)0.0221 (12)0.0225 (11)0.0016 (9)0.0015 (9)−0.0008 (9)
C50.0229 (11)0.0227 (12)0.0246 (11)0.0031 (10)0.0003 (9)0.0041 (9)
C5A0.0280 (12)0.0323 (13)0.0279 (12)−0.0039 (10)0.0031 (10)−0.0008 (10)
C60.0273 (13)0.0218 (12)0.0311 (12)−0.0017 (10)−0.0004 (10)0.0003 (10)
C70.0307 (13)0.0207 (12)0.0243 (11)0.0014 (10)0.0024 (10)−0.0015 (9)
C7A0.0244 (11)0.0203 (11)0.0214 (11)0.0032 (9)0.0014 (9)0.0027 (9)
C80.0228 (11)0.0195 (11)0.0235 (11)−0.0008 (9)0.0045 (9)0.0001 (9)
C8A0.0309 (12)0.0272 (13)0.0254 (11)0.0037 (10)0.0068 (10)0.0010 (10)
C9A0.0243 (12)0.0203 (11)0.0237 (11)−0.0001 (9)0.0053 (9)0.0002 (9)
C90.0306 (13)0.0245 (12)0.0224 (11)−0.0017 (10)0.0060 (10)−0.0003 (10)
C100.0302 (12)0.0192 (12)0.0291 (12)0.0022 (10)0.0105 (10)−0.0011 (10)
C110.0230 (11)0.0218 (12)0.0292 (11)0.0002 (9)0.0060 (9)0.0038 (9)
C11A0.0331 (13)0.0281 (13)0.0407 (13)0.0029 (11)0.0023 (11)0.0058 (10)
C120.0215 (12)0.0226 (12)0.0281 (12)−0.0022 (10)0.0036 (10)0.0030 (9)
C130.0276 (12)0.0174 (11)0.0239 (10)−0.0001 (9)0.0084 (9)−0.0005 (9)
O140.0340 (9)0.0214 (8)0.0251 (8)0.0031 (7)−0.0007 (7)−0.0010 (6)
C150.0247 (12)0.0221 (12)0.0258 (11)0.0006 (10)0.0054 (10)0.0016 (9)

Geometric parameters (Å, °)

C1—O1A1.394 (2)C7—H7A0.97 (2)
C1—O141.441 (2)C7A—C81.561 (3)
C1—O21.447 (2)C8—C9A1.545 (3)
C1—C151.516 (3)C8—C151.545 (3)
O1A—C1B1.471 (3)C8—C8A1.549 (3)
C1B—C1C1.506 (3)C8A—H810.9600
C1B—H1B11.01 (2)C8A—H820.9600
C1B—H1B21.03 (2)C8A—H830.9600
C1C—H1C10.9600C9A—C91.396 (3)
C1C—H1C20.9600C9A—C131.406 (3)
C1C—H1C30.9600C9—C101.404 (3)
O2—C31.402 (2)C9—H9A1.02 (2)
C3—C7A1.408 (3)C10—C111.412 (3)
C3—C41.417 (3)C10—H10A1.01 (2)
C4—C51.401 (3)C11—C121.404 (3)
C4—H4A1.00 (2)C11—C11A1.521 (3)
C5—C61.412 (3)C11A—H1110.9600
C5—C5A1.537 (3)C11A—H1120.9600
C5A—H510.9600C11A—H1130.9600
C5A—H520.9600C12—C131.404 (3)
C5A—H530.9600C12—H12A0.97 (2)
C6—C71.416 (3)C13—O141.394 (2)
C6—H6A1.01 (2)C15—H15A1.03 (2)
C7—C7A1.410 (3)C15—H15B1.01 (2)
O1A—C1—O14106.32 (16)C9A—C8—C15105.53 (16)
O1A—C1—O2106.81 (16)C9A—C8—C8A113.52 (16)
O14—C1—O2107.79 (15)C15—C8—C8A109.48 (16)
O1A—C1—C15110.49 (16)C9A—C8—C7A108.30 (15)
O14—C1—C15112.89 (17)C15—C8—C7A107.35 (16)
O2—C1—C15112.18 (17)C8A—C8—C7A112.28 (16)
C1—O1A—C1B115.89 (15)C8—C8A—H81109.5
O1A—C1B—C1C107.24 (18)C8—C8A—H82109.5
O1A—C1B—H1B1109.9 (12)H81—C8A—H82109.5
C1C—C1B—H1B1111.0 (13)C8—C8A—H83109.5
O1A—C1B—H1B2109.0 (12)H81—C8A—H83109.5
C1C—C1B—H1B2111.9 (12)H82—C8A—H83109.5
H1B1—C1B—H1B2107.7 (17)C9—C9A—C13117.17 (19)
C1B—C1C—H1C1109.5C9—C9A—C8123.89 (19)
C1B—C1C—H1C2109.5C13—C9A—C8118.92 (17)
H1C1—C1C—H1C2109.5C9A—C9—C10120.9 (2)
C1B—C1C—H1C3109.5C9A—C9—H9A119.4 (11)
H1C1—C1C—H1C3109.5C10—C9—H9A119.7 (11)
H1C2—C1C—H1C3109.5C9—C10—C11121.6 (2)
C3—O2—C1117.55 (15)C9—C10—H10A120.4 (12)
O2—C3—C7A122.45 (18)C11—C10—H10A118.0 (12)
O2—C3—C4115.67 (17)C12—C11—C10117.93 (19)
C7A—C3—C4121.88 (19)C12—C11—C11A120.07 (19)
C5—C4—C3121.08 (19)C10—C11—C11A121.97 (19)
C5—C4—H4A119.3 (12)C11—C11A—H111109.5
C3—C4—H4A119.6 (12)C11—C11A—H112109.5
C4—C5—C6117.72 (19)H111—C11A—H112109.5
C4—C5—C5A121.32 (18)C11—C11A—H113109.5
C6—C5—C5A120.93 (18)H111—C11A—H113109.5
C5—C5A—H51109.5H112—C11A—H113109.5
C5—C5A—H52109.5C13—C12—C11119.6 (2)
H51—C5A—H52109.5C13—C12—H12A120.0 (14)
C5—C5A—H53109.5C11—C12—H12A120.4 (14)
H51—C5A—H53109.5O14—C13—C12114.50 (18)
H52—C5A—H53109.5O14—C13—C9A122.64 (18)
C5—C6—C7120.8 (2)C12—C13—C9A122.85 (19)
C5—C6—H6A120.4 (11)C13—O14—C1119.16 (15)
C7—C6—H6A118.8 (11)C1—C15—C8108.64 (17)
C7A—C7—C6121.9 (2)C1—C15—H15A110.6 (12)
C7A—C7—H7A119.4 (12)C8—C15—H15A107.0 (12)
C6—C7—H7A118.7 (12)C1—C15—H15B110.1 (12)
C3—C7A—C7116.55 (19)C8—C15—H15B110.6 (12)
C3—C7A—C8120.42 (18)H15A—C15—H15B109.9 (17)
C7—C7A—C8122.99 (17)
O14—C1—O1A—C1B52.0 (2)C8A—C8—C9A—C927.8 (3)
O2—C1—O1A—C1B−62.9 (2)C7A—C8—C9A—C9−97.6 (2)
C15—C1—O1A—C1B174.86 (18)C15—C8—C9A—C13−33.8 (2)
C1—O1A—C1B—C1C177.22 (17)C8A—C8—C9A—C13−153.74 (18)
O1A—C1—O2—C3−159.04 (15)C7A—C8—C9A—C1380.8 (2)
O14—C1—O2—C387.06 (19)C13—C9A—C9—C10−0.3 (3)
C15—C1—O2—C3−37.8 (2)C8—C9A—C9—C10178.18 (18)
C1—O2—C3—C7A5.5 (3)C9A—C9—C10—C110.2 (3)
C1—O2—C3—C4−174.66 (17)C9—C10—C11—C120.4 (3)
O2—C3—C4—C5178.45 (17)C9—C10—C11—C11A−177.78 (19)
C7A—C3—C4—C5−1.7 (3)C10—C11—C12—C13−0.8 (3)
C3—C4—C5—C6−0.6 (3)C11A—C11—C12—C13177.37 (19)
C3—C4—C5—C5A177.54 (18)C11—C12—C13—O14−178.21 (17)
C4—C5—C6—C72.0 (3)C11—C12—C13—C9A0.7 (3)
C5A—C5—C6—C7−176.14 (19)C9—C9A—C13—O14178.71 (18)
C5—C6—C7—C7A−1.2 (3)C8—C9A—C13—O140.1 (3)
O2—C3—C7A—C7−177.66 (17)C9—C9A—C13—C12−0.1 (3)
C4—C3—C7A—C72.5 (3)C8—C9A—C13—C12−178.73 (18)
O2—C3—C7A—C80.3 (3)C12—C13—O14—C1−174.43 (17)
C4—C3—C7A—C8−179.47 (18)C9A—C13—O14—C16.6 (3)
C6—C7—C7A—C3−1.1 (3)O1A—C1—O14—C13144.54 (16)
C6—C7—C7A—C8−179.04 (18)O2—C1—O14—C13−101.23 (18)
C3—C7A—C8—C9A−88.6 (2)C15—C1—O14—C1323.2 (2)
C7—C7A—C8—C9A89.3 (2)O1A—C1—C15—C8−177.26 (16)
C3—C7A—C8—C1524.9 (2)O14—C1—C15—C8−58.4 (2)
C7—C7A—C8—C15−157.21 (19)O2—C1—C15—C863.7 (2)
C3—C7A—C8—C8A145.29 (18)C9A—C8—C15—C161.0 (2)
C7—C7A—C8—C8A−36.8 (3)C8A—C8—C15—C1−176.52 (17)
C15—C8—C9A—C9147.7 (2)C7A—C8—C15—C1−54.4 (2)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT2970).

References

  • Klei, H. E., Callegari, E., Edwards, J. M. & Kelly, J. A. (1995). Acta Cryst. C51, 2621–2624.
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