The structure of the title compound, C
20H
18O
2, consists of a dimeric arrangement of benzofuran molecules around an inversion centre, linked
via C—H
O hydrogen bonds. There are also C—H
π ring interactions. All these interactions result in the formation of infinite chains parallel to the [100] axis. The cyclobutane ring is puckered, with a dihedral angle of 29.03 (13)° between the two three-atom planes.
Supporting information
CCDC reference: 245920
Salicylaldehyde (1.342 g, 1.15 ml, 11 mmol), potassium carbonate (2.07 g, 15 mmol) and acetonitrile (100 ml) were placed in a 500 ml two-necked flask fitted with a reflux condenser, and the mixture was stirred for 1 h at room temperature. To this solution, a solution of 1-phenyl-1-methyl-3-(2-chloro-1-oxoethyl)cyclobutane (2.225 g, 10 mmol) in acetonitrile (100 ml) was added dropwise over a period of about 30 min. and refluxed for 4 h. The course of the reaction was monitored by IR spectroscopy. The solvent was removed under reduced pressure, the residue was extracted with diethyl ether and the ether phase was dried on magnesium sulfate. After filtration and removal of the solvent under reduced pressure, compound (I) was crystallized from acetonitrile (yield 84%, m.p. 429–430 K).
H atoms were placed in idealized positions, with C—H distances in the range 0.93–0.98 Å and Uiso(H) = 1.2Ueq(C) (1.5 for the methyl group).
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
(Benzofuran-2-yl)(3-methyl-3-phenylcyclobutyl)methanone
top
Crystal data top
C20H18O2 | F(000) = 616 |
Mr = 290.34 | Dx = 1.263 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 5297 reflections |
a = 6.1497 (7) Å | θ = 1.8–26.8° |
b = 14.6894 (19) Å | µ = 0.08 mm−1 |
c = 16.922 (2) Å | T = 293 K |
β = 92.60 (1)° | Rod, colourless |
V = 1527.1 (3) Å3 | 0.50 × 0.25 × 0.11 mm |
Z = 4 | |
Data collection top
Stoe IPDS 2 diffractometer | 1602 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.117 |
Graphite monochromator | θmax = 25.0°, θmin = 1.8° |
Detector resolution: 6.67 pixels mm-1 | h = −7→7 |
ϕ scans | k = −17→17 |
11652 measured reflections | l = −20→20 |
2685 independent reflections | |
Refinement top
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.098 | H-atom parameters constrained |
S = 0.83 | w = 1/[σ2(Fo2) + (0.0453P)2] where P = (Fo2 + 2Fc2)/3 |
2685 reflections | (Δ/σ)max < 0.001 |
200 parameters | Δρmax = 0.13 e Å−3 |
0 restraints | Δρmin = −0.16 e Å−3 |
Crystal data top
C20H18O2 | V = 1527.1 (3) Å3 |
Mr = 290.34 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.1497 (7) Å | µ = 0.08 mm−1 |
b = 14.6894 (19) Å | T = 293 K |
c = 16.922 (2) Å | 0.50 × 0.25 × 0.11 mm |
β = 92.60 (1)° | |
Data collection top
Stoe IPDS 2 diffractometer | 1602 reflections with I > 2σ(I) |
11652 measured reflections | Rint = 0.117 |
2685 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.098 | H-atom parameters constrained |
S = 0.83 | Δρmax = 0.13 e Å−3 |
2685 reflections | Δρmin = −0.16 e Å−3 |
200 parameters | |
Special details top
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) top | x | y | z | Uiso*/Ueq | |
O1 | 1.14325 (19) | 0.24820 (8) | 0.50310 (7) | 0.0453 (3) | |
O2 | 0.8586 (2) | 0.44383 (10) | 0.56316 (8) | 0.0604 (4) | |
C1 | 0.7713 (3) | 0.34439 (12) | 0.45466 (11) | 0.0411 (4) | |
H1 | 0.7294 | 0.2807 | 0.4621 | 0.049* | |
C2 | 0.5732 (3) | 0.39917 (14) | 0.42493 (11) | 0.0455 (5) | |
H2A | 0.5822 | 0.4635 | 0.4375 | 0.055* | |
H2B | 0.4354 | 0.3737 | 0.4399 | 0.055* | |
C3 | 0.6323 (3) | 0.37619 (12) | 0.33906 (10) | 0.0389 (4) | |
C4 | 0.8655 (3) | 0.35623 (13) | 0.37205 (10) | 0.0429 (5) | |
H4A | 0.9645 | 0.4073 | 0.3684 | 0.051* | |
H4B | 0.9283 | 0.3011 | 0.3512 | 0.051* | |
C5 | 1.0984 (3) | 0.32396 (12) | 0.54943 (10) | 0.0402 (5) | |
C6 | 1.2504 (3) | 0.33428 (12) | 0.60813 (11) | 0.0447 (5) | |
H6 | 1.2542 | 0.3798 | 0.6464 | 0.054* | |
C7 | 1.4058 (3) | 0.26243 (13) | 0.60122 (11) | 0.0429 (5) | |
C8 | 1.6002 (3) | 0.23670 (14) | 0.64054 (12) | 0.0534 (5) | |
H8 | 1.6544 | 0.2692 | 0.6843 | 0.064* | |
C9 | 1.7101 (3) | 0.16238 (14) | 0.61349 (13) | 0.0565 (6) | |
H9 | 1.8398 | 0.1444 | 0.6394 | 0.068* | |
C10 | 1.6306 (3) | 0.11371 (14) | 0.54820 (13) | 0.0557 (6) | |
H10 | 1.7087 | 0.0637 | 0.5312 | 0.067* | |
C11 | 1.4401 (3) | 0.13709 (13) | 0.50778 (13) | 0.0514 (5) | |
H11 | 1.3866 | 0.1042 | 0.4641 | 0.062* | |
C12 | 1.3323 (3) | 0.21215 (12) | 0.53570 (11) | 0.0409 (5) | |
C13 | 0.9046 (3) | 0.37640 (13) | 0.52525 (11) | 0.0431 (5) | |
C14 | 0.5176 (4) | 0.28878 (13) | 0.31006 (14) | 0.0608 (6) | |
H14A | 0.3645 | 0.3002 | 0.3019 | 0.091* | |
H14B | 0.5400 | 0.2417 | 0.3490 | 0.091* | |
H14C | 0.5765 | 0.2697 | 0.2612 | 0.091* | |
C15 | 0.5987 (3) | 0.44929 (12) | 0.27737 (10) | 0.0396 (4) | |
C16 | 0.4100 (3) | 0.50051 (13) | 0.27306 (12) | 0.0493 (5) | |
H16 | 0.3054 | 0.4917 | 0.3103 | 0.059* | |
C17 | 0.3746 (4) | 0.56472 (14) | 0.21401 (14) | 0.0612 (6) | |
H17 | 0.2463 | 0.5983 | 0.2117 | 0.073* | |
C18 | 0.5278 (5) | 0.57890 (15) | 0.15901 (15) | 0.0707 (7) | |
H18 | 0.5044 | 0.6221 | 0.1193 | 0.085* | |
C19 | 0.7172 (4) | 0.52849 (18) | 0.16311 (13) | 0.0724 (7) | |
H19 | 0.8223 | 0.5380 | 0.1262 | 0.087* | |
C20 | 0.7517 (3) | 0.46405 (15) | 0.22153 (12) | 0.0567 (5) | |
H20 | 0.8795 | 0.4301 | 0.2233 | 0.068* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0512 (8) | 0.0414 (7) | 0.0429 (7) | −0.0010 (6) | −0.0042 (6) | −0.0052 (6) |
O2 | 0.0709 (10) | 0.0553 (9) | 0.0549 (9) | 0.0100 (7) | 0.0028 (8) | −0.0135 (7) |
C1 | 0.0445 (10) | 0.0386 (10) | 0.0403 (10) | −0.0022 (8) | 0.0034 (9) | 0.0022 (8) |
C2 | 0.0443 (11) | 0.0518 (12) | 0.0410 (11) | 0.0014 (9) | 0.0068 (9) | 0.0056 (9) |
C3 | 0.0438 (10) | 0.0375 (9) | 0.0355 (10) | −0.0017 (8) | 0.0020 (9) | −0.0003 (8) |
C4 | 0.0472 (10) | 0.0419 (10) | 0.0400 (11) | 0.0026 (9) | 0.0055 (9) | −0.0022 (8) |
C5 | 0.0480 (11) | 0.0362 (10) | 0.0366 (10) | −0.0020 (9) | 0.0036 (9) | −0.0036 (8) |
C6 | 0.0568 (12) | 0.0399 (10) | 0.0371 (11) | −0.0024 (9) | −0.0016 (9) | −0.0024 (8) |
C7 | 0.0502 (11) | 0.0395 (10) | 0.0387 (10) | −0.0055 (9) | −0.0007 (9) | 0.0037 (8) |
C8 | 0.0627 (13) | 0.0497 (12) | 0.0468 (12) | −0.0042 (11) | −0.0089 (11) | 0.0023 (10) |
C9 | 0.0587 (12) | 0.0519 (12) | 0.0579 (14) | 0.0052 (11) | −0.0076 (11) | 0.0119 (11) |
C10 | 0.0661 (14) | 0.0402 (11) | 0.0609 (14) | 0.0067 (10) | 0.0019 (12) | 0.0046 (10) |
C11 | 0.0618 (13) | 0.0406 (11) | 0.0514 (12) | −0.0009 (10) | −0.0031 (11) | −0.0025 (9) |
C12 | 0.0462 (11) | 0.0352 (10) | 0.0408 (11) | −0.0049 (8) | −0.0023 (9) | 0.0016 (8) |
C13 | 0.0515 (11) | 0.0406 (10) | 0.0379 (10) | −0.0040 (9) | 0.0082 (9) | 0.0030 (9) |
C14 | 0.0726 (14) | 0.0442 (12) | 0.0640 (14) | −0.0102 (10) | −0.0148 (12) | 0.0035 (10) |
C15 | 0.0460 (11) | 0.0383 (10) | 0.0346 (10) | −0.0026 (8) | 0.0004 (9) | −0.0028 (8) |
C16 | 0.0527 (11) | 0.0474 (11) | 0.0475 (12) | 0.0030 (10) | −0.0004 (10) | −0.0023 (9) |
C17 | 0.0733 (15) | 0.0458 (12) | 0.0627 (15) | 0.0086 (11) | −0.0172 (13) | −0.0032 (11) |
C18 | 0.0996 (19) | 0.0518 (13) | 0.0593 (15) | −0.0098 (14) | −0.0133 (15) | 0.0162 (12) |
C19 | 0.0839 (17) | 0.0785 (17) | 0.0560 (14) | −0.0071 (15) | 0.0161 (13) | 0.0220 (13) |
C20 | 0.0611 (13) | 0.0592 (13) | 0.0507 (12) | 0.0050 (11) | 0.0109 (11) | 0.0086 (10) |
Geometric parameters (Å, º) top
O1—C12 | 1.371 (2) | C8—H8 | 0.9300 |
O1—C5 | 1.396 (2) | C9—C10 | 1.386 (3) |
O2—C13 | 1.220 (2) | C9—H9 | 0.9300 |
C1—C13 | 1.494 (2) | C10—C11 | 1.374 (3) |
C1—C2 | 1.526 (2) | C10—H10 | 0.9300 |
C1—C4 | 1.547 (3) | C11—C12 | 1.381 (3) |
C1—H1 | 0.9800 | C11—H11 | 0.9300 |
C2—C3 | 1.551 (3) | C14—H14A | 0.9600 |
C2—H2A | 0.9700 | C14—H14B | 0.9600 |
C2—H2B | 0.9700 | C14—H14C | 0.9600 |
C3—C15 | 1.505 (2) | C15—C20 | 1.380 (3) |
C3—C14 | 1.535 (2) | C15—C16 | 1.382 (3) |
C3—C4 | 1.543 (2) | C16—C17 | 1.384 (3) |
C4—H4A | 0.9700 | C16—H16 | 0.9300 |
C4—H4B | 0.9700 | C17—C18 | 1.370 (3) |
C5—C6 | 1.341 (2) | C17—H17 | 0.9300 |
C5—C13 | 1.462 (3) | C18—C19 | 1.379 (3) |
C6—C7 | 1.432 (3) | C18—H18 | 0.9300 |
C6—H6 | 0.9300 | C19—C20 | 1.378 (3) |
C7—C12 | 1.390 (3) | C19—H19 | 0.9300 |
C7—C8 | 1.394 (2) | C20—H20 | 0.9300 |
C8—C9 | 1.374 (3) | | |
| | | |
C12—O1—C5 | 105.52 (13) | C8—C9—H9 | 119.5 |
C13—C1—C2 | 119.90 (16) | C10—C9—H9 | 119.5 |
C13—C1—C4 | 118.23 (15) | C11—C10—C9 | 122.0 (2) |
C2—C1—C4 | 88.21 (13) | C11—C10—H10 | 119.0 |
C13—C1—H1 | 109.6 | C9—C10—H10 | 119.0 |
C2—C1—H1 | 109.6 | C10—C11—C12 | 116.17 (19) |
C4—C1—H1 | 109.6 | C10—C11—H11 | 121.9 |
C1—C2—C3 | 88.67 (14) | C12—C11—H11 | 121.9 |
C1—C2—H2A | 113.9 | O1—C12—C11 | 125.61 (16) |
C3—C2—H2A | 113.9 | O1—C12—C7 | 110.77 (16) |
C1—C2—H2B | 113.9 | C11—C12—C7 | 123.62 (17) |
C3—C2—H2B | 113.9 | O2—C13—C5 | 119.06 (16) |
H2A—C2—H2B | 111.1 | O2—C13—C1 | 122.99 (17) |
C15—C3—C14 | 109.18 (14) | C5—C13—C1 | 117.95 (16) |
C15—C3—C4 | 118.83 (16) | C3—C14—H14A | 109.5 |
C14—C3—C4 | 111.27 (15) | C3—C14—H14B | 109.5 |
C15—C3—C2 | 117.64 (15) | H14A—C14—H14B | 109.5 |
C14—C3—C2 | 110.97 (16) | C3—C14—H14C | 109.5 |
C4—C3—C2 | 87.45 (13) | H14A—C14—H14C | 109.5 |
C3—C4—C1 | 88.19 (13) | H14B—C14—H14C | 109.5 |
C3—C4—H4A | 114.0 | C20—C15—C16 | 118.35 (18) |
C1—C4—H4A | 114.0 | C20—C15—C3 | 120.71 (17) |
C3—C4—H4B | 114.0 | C16—C15—C3 | 120.88 (18) |
C1—C4—H4B | 114.0 | C15—C16—C17 | 120.9 (2) |
H4A—C4—H4B | 111.2 | C15—C16—H16 | 119.6 |
C6—C5—O1 | 110.92 (15) | C17—C16—H16 | 119.6 |
C6—C5—C13 | 132.83 (17) | C18—C17—C16 | 120.2 (2) |
O1—C5—C13 | 116.25 (14) | C18—C17—H17 | 119.9 |
C5—C6—C7 | 107.55 (16) | C16—C17—H17 | 119.9 |
C5—C6—H6 | 126.2 | C17—C18—C19 | 119.3 (2) |
C7—C6—H6 | 126.2 | C17—C18—H18 | 120.4 |
C12—C7—C8 | 118.50 (18) | C19—C18—H18 | 120.4 |
C12—C7—C6 | 105.24 (15) | C20—C19—C18 | 120.5 (2) |
C8—C7—C6 | 136.21 (18) | C20—C19—H19 | 119.8 |
C9—C8—C7 | 118.76 (18) | C18—C19—H19 | 119.8 |
C9—C8—H8 | 120.6 | C19—C20—C15 | 120.8 (2) |
C7—C8—H8 | 120.6 | C19—C20—H20 | 119.6 |
C8—C9—C10 | 120.94 (19) | C15—C20—H20 | 119.6 |
| | | |
C13—C1—C2—C3 | 142.35 (17) | C6—C7—C12—O1 | −0.4 (2) |
C4—C1—C2—C3 | 20.48 (13) | C8—C7—C12—C11 | 0.8 (3) |
C1—C2—C3—C15 | −141.99 (16) | C6—C7—C12—C11 | 178.70 (18) |
C1—C2—C3—C14 | 91.29 (16) | C6—C5—C13—O2 | −0.7 (3) |
C1—C2—C3—C4 | −20.54 (13) | O1—C5—C13—O2 | −179.31 (17) |
C15—C3—C4—C1 | 140.63 (16) | C6—C5—C13—C1 | 179.4 (2) |
C14—C3—C4—C1 | −91.28 (18) | O1—C5—C13—C1 | 0.7 (2) |
C2—C3—C4—C1 | 20.26 (13) | C2—C1—C13—O2 | 2.7 (3) |
C13—C1—C4—C3 | −143.91 (16) | C4—C1—C13—O2 | 108.2 (2) |
C2—C1—C4—C3 | −20.59 (13) | C2—C1—C13—C5 | −177.30 (17) |
C12—O1—C5—C6 | −0.42 (19) | C4—C1—C13—C5 | −71.8 (2) |
C12—O1—C5—C13 | 178.52 (15) | C14—C3—C15—C20 | −94.4 (2) |
O1—C5—C6—C7 | 0.2 (2) | C4—C3—C15—C20 | 34.7 (2) |
C13—C5—C6—C7 | −178.55 (19) | C2—C3—C15—C20 | 138.01 (18) |
C5—C6—C7—C12 | 0.2 (2) | C14—C3—C15—C16 | 82.7 (2) |
C5—C6—C7—C8 | 177.4 (2) | C4—C3—C15—C16 | −148.23 (17) |
C12—C7—C8—C9 | −0.6 (3) | C2—C3—C15—C16 | −44.9 (2) |
C6—C7—C8—C9 | −177.6 (2) | C20—C15—C16—C17 | 0.3 (3) |
C7—C8—C9—C10 | 0.2 (3) | C3—C15—C16—C17 | −176.87 (16) |
C8—C9—C10—C11 | 0.0 (3) | C15—C16—C17—C18 | −0.5 (3) |
C9—C10—C11—C12 | 0.3 (3) | C16—C17—C18—C19 | 0.1 (3) |
C5—O1—C12—C11 | −178.59 (19) | C17—C18—C19—C20 | 0.4 (4) |
C5—O1—C12—C7 | 0.5 (2) | C18—C19—C20—C15 | −0.6 (3) |
C10—C11—C12—O1 | 178.34 (18) | C16—C15—C20—C19 | 0.2 (3) |
C10—C11—C12—C7 | −0.7 (3) | C3—C15—C20—C19 | 177.40 (19) |
C8—C7—C12—O1 | −178.29 (16) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16···O2i | 0.93 | 2.59 | 3.390 (2) | 145 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | C20H18O2 |
Mr | 290.34 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 6.1497 (7), 14.6894 (19), 16.922 (2) |
β (°) | 92.60 (1) |
V (Å3) | 1527.1 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.50 × 0.25 × 0.11 |
|
Data collection |
Diffractometer | Stoe IPDS 2 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11652, 2685, 1602 |
Rint | 0.117 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.098, 0.83 |
No. of reflections | 2685 |
No. of parameters | 200 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.13, −0.16 |
Selected geometric parameters (Å, º) topO1—C5 | 1.396 (2) | C3—C14 | 1.535 (2) |
O2—C13 | 1.220 (2) | C5—C6 | 1.341 (2) |
C1—C13 | 1.494 (2) | C5—C13 | 1.462 (3) |
C3—C15 | 1.505 (2) | | |
| | | |
C13—C1—C2 | 119.90 (16) | C6—C5—C13 | 132.83 (17) |
C13—C1—C4 | 118.23 (15) | O1—C5—C13 | 116.25 (14) |
C15—C3—C14 | 109.18 (14) | O2—C13—C5 | 119.06 (16) |
C14—C3—C2 | 110.97 (16) | O2—C13—C1 | 122.99 (17) |
C6—C5—O1 | 110.92 (15) | C5—C13—C1 | 117.95 (16) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16···O2i | 0.93 | 2.59 | 3.390 (2) | 145 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Benzofurans have attracted widespread interest, in view of their biological activity, their presence in a large number of natural products and their potential as pharmacological agents. Consequently, diverse synthetic strategies have been developed to build this fused skeleton, commonly starting from a benzene ring with the appropriate substituents. A large number of syntheses of the heterocyclic moiety in benzofuran are based on the formation of O1—C5 or C5—C6 bonds as the ring-closure step (Cruz & Tamariz, 2004). In this paper, we report the molecular and crystal structure of the title benzofuran, (I). \sch
The present crystal structure determination of (I) was carried out to determine the strength of the hydrogen-bonding capabilities of benzofuran and carbonyl, as well as of the C—H···π interactions between the molecules. Compound (I) consists of cyclobutyl and benzofuran rings linked through a carbonyl group (Fig. 1). Selected bond lengths and angles in (I) are shown in Table 1.
The dihedral angles between the phenyl ring A (C15—C20), the cyclobutane ring B (C1—C4), the benzofuran ring C (O1/C5/C6/C7/C12) and the benzene ring D (C7—C12) are A/B 32.74 (10), A/C 73.60 (6), A/D 73.66 (6), B/C 46.34 (10), B/D 45.81 (9) and C/D 1.64 (14)°, i.e. rings C and D are nearly coplanar. The steric interaction between the substituent groups on the cyclobutane ring means that this ring deviates significantly from planarity. Literature values for the puckering of the cyclobutane ring are 23.5° (Swenson et al., 1997) and 2.89 (37)° (Özdemir et al., 2004a). In this study, the C4/C1/C2 plane forms a dihedral angle of 29.03 (13)° with the C2/C3/C4 plane, which deviates from the values reported in the previous studies. The geometry of the cyclobutane ring is due to the steric effect of the methyl group. The C2—C1—C13—C5 torsion angle is −177.46 (16)°.
In this compound, atom H16 of the A ring (C15—C20) acts as a donor, resulting in the formation of C—H···O hydrogen bonds which link two molecules related by an inversion centre (Fig. 2). Of greater interest are the intermolecular π-ring interactions between the H atoms of the cyclobutane and the benzofuran rings, which contribute to the crystal packing by forming an infinite chain of dimers. These C—H···π interactions, between rings D and C, the benzofuran rings, and atoms H1(C1) and H2B(C2) of the cyclobutane, have the following geometric parameters. Firstly, the distance between atom H1 bonded to atom C1 and the centre, M, of ring Dii (C7—C12) is 2.716 Å [symmetry code: (ii) x − 1, y, z] and the C1—H1···M angle is 135.1°. Secondly, the distance between atom H2B bonded to atom C2 and the centre, K, of ring Cii (C5/C6/C7/C12/O1), is 2.779 Å and the C2—H2B···K angle is 142.0°.
The results obtained in this study indicate that there are some differences in the geometry of (I) compared with that of other compounds containing benzofuran or cyclobutane groups, such as those reported by Batsanov & Perepichka (2002) and Özdemir et al. (2004 Which reference?). In the reported study (Which?), the crystal packing is mainly stabilized by intermolecular hydrogen bonds, which are highly effective in forming polymeric chains (Özdemir et al., 2004b). From the results presented in this paper, it can be said that C—H···O hydrogen bonds link two molecules through an inversion centre to form a dimer, similar to what was found by Batsanov & Perepichka (2002). Besides these hydrogen bonds, there is an interesting π-ring interaction which stabilizes the crystal structure of (I). Dipole-dipole and van der Waals interactions are also effective in the molecular packing in the crystal structure.