organic compounds
5-Bromo-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran
aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, and bDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
*Correspondence e-mail: w.harrison@abdn.ac.uk
The title compound, C14H10BrFO, possesses normal geometrical parameters. The dihedral angle between the two ring systems is 71.50 (9)°. An unusually short intermolecular Br⋯Br contact of 3.4311 (5) Å occurs.
Comment
The title compound, (I), is an intermediate in the synthesis of the antidepressant drug citalopram (Liechti et al., 2000). More generally, phthalans show distinctive redox chemistry (Azzena et al., 1996). We have previously deposited (CSD-260624; Cambridge Structural Database; Allen, 2002) data for a poor quality structure from a twinned crystal of (I).
The geometrical parameters for (I) are normal. Each molecule of (I) is chiral (the arbitrarily chosen has an S conformation at C7), but crystal symmetry generates a of the two enantiomers. The nine-membered isobenzofuran ring system (C7–C14/O1) is almost planar [r.m.s. deviation from the mean plane = 0.018 Å; maximum = 0.038 (3) Å for C14] and the dihedral angle between the two ring systems (C7–C14/O1 and C1–C6) is 71.50 (9)°.
A PLATON (Spek, 2003) analysis of (I) identified two possible C—H⋯F interactions (Table 1) that may help to stabilize the crystal packing (Fig. 2). There are no significant π–π stacking interactions in (I).
Inversion symmetry generates a short intermolecular Br1⋯Br1i [symmetry code: (i) 2 − x, −y, 1 − z] separation of 3.4311 (5) Å which is significantly less than the van der Waals contact distance of 3.70 Å for two Br atoms (Bondi, 1964). Some workers have ascribed specific attractive forces to such short intermolecular halogen–halogen contacts (Desiraju & Parthasarathy, 1989). A database survey of such contacts by Eriksson & Hu (2001) shows that the present separation lies at the lower end of the observed range of intermolecular Br⋯Br distances. However, these workers are less certain of the nature of such contacts, and suggest that they may be the consequence – rather than the cause – of the crystal packing.
In the related 1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile [i.e. where a cyanide group replaces the Br atom in (I)], there are two molecules in the with distinctly different degrees of twist between their ring systems (Yathirajan et al., 2004).
Experimental
5-Bromo-3H-isobenzofuran-1-one (2.13 g, 10 mmol) was subjected to a Grignard reaction with 4-fluorophenyl magnesium bromide (2.4 g, 12 mmol) in tetrahydrofuran (10 ml) at 273 K. The resulting product was treated with sodium borohydride (0.37 g, 10 mmol) in methanol (10 ml) to obtain the diol, which was cyclized with p-toluene sulfonic acid (1 g, 5.81 mmol) in toluene (10 ml) at 353 K, yielding crude (I). Diffraction-quality crystals were obtained by recrystallization from n-hexane (Bigler et al., 1977) (m.p. 318 K).
Crystal data
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Refinement
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The H atoms were positioned geometrically, with C—H = 0.95–0.99 Å, and refined as riding, with Uiso(H) = 1.2Ueq(carrier).
Data collection: COLLECT (Nonius, 1998); cell SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536806009810/xu2018sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536806009810/xu2018Isup2.hkl
Data collection: COLLECT (Nonius, 1998); cell
SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.C14H10BrFO | F(000) = 584 |
Mr = 293.13 | Dx = 1.689 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2707 reflections |
a = 6.0560 (3) Å | θ = 1.0–27.5° |
b = 7.8659 (4) Å | µ = 3.56 mm−1 |
c = 24.2289 (14) Å | T = 120 K |
β = 92.542 (3)° | Block, yellow |
V = 1153.03 (11) Å3 | 0.24 × 0.15 × 0.10 mm |
Z = 4 |
Nonius KappaCCD diffractometer | 2630 independent reflections |
Radiation source: fine-focus sealed tube | 1742 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.072 |
ω and φ scans | θmax = 27.6°, θmin = 3.4° |
Absorption correction: multi-scan (SADABS; Bruker, 2003) | h = −7→7 |
Tmin = 0.482, Tmax = 0.718 | k = −10→10 |
12389 measured reflections | l = −31→27 |
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)] = 0.041 | H-atom parameters constrained |
wR(F2) = 0.079 | w = 1/[σ2(Fo2) + (0.0257P)2 + 0.4294P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
2630 reflections | Δρmax = 0.56 e Å−3 |
155 parameters | Δρmin = −0.40 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0023 (6) |
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 | ||
C1 | 0.3615 (5) | 0.6855 (5) | 0.26210 (15) | 0.0366 (9) | |
H1 | 0.5049 | 0.7253 | 0.2731 | 0.044* | |
C2 | 0.3091 (6) | 0.6559 (5) | 0.20662 (15) | 0.0420 (9) | |
H2 | 0.4144 | 0.6748 | 0.1794 | 0.050* | |
C3 | 0.1012 (6) | 0.5986 (4) | 0.19235 (14) | 0.0357 (9) | |
C4 | −0.0572 (6) | 0.5688 (4) | 0.22975 (14) | 0.0335 (8) | |
H4 | −0.2002 | 0.5291 | 0.2183 | 0.040* | |
C5 | −0.0007 (5) | 0.5990 (4) | 0.28501 (14) | 0.0311 (8) | |
H5 | −0.1070 | 0.5790 | 0.3119 | 0.037* | |
C6 | 0.2072 (5) | 0.6577 (4) | 0.30177 (13) | 0.0274 (7) | |
C7 | 0.2636 (5) | 0.6902 (4) | 0.36229 (13) | 0.0276 (7) | |
H7 | 0.1256 | 0.7199 | 0.3813 | 0.033* | |
C8 | 0.3774 (5) | 0.5441 (4) | 0.39220 (12) | 0.0232 (7) | |
C9 | 0.3061 (5) | 0.3792 (4) | 0.39959 (13) | 0.0274 (8) | |
H9 | 0.1672 | 0.3430 | 0.3841 | 0.033* | |
C10 | 0.4407 (5) | 0.2669 (4) | 0.43009 (13) | 0.0263 (8) | |
H10 | 0.3949 | 0.1529 | 0.4356 | 0.032* | |
C11 | 0.6416 (5) | 0.3234 (4) | 0.45219 (12) | 0.0258 (7) | |
C12 | 0.7142 (5) | 0.4893 (4) | 0.44546 (13) | 0.0272 (8) | |
H12 | 0.8528 | 0.5262 | 0.4610 | 0.033* | |
C13 | 0.5774 (5) | 0.5985 (4) | 0.41530 (13) | 0.0260 (7) | |
C14 | 0.6066 (5) | 0.7837 (4) | 0.40280 (15) | 0.0334 (8) | |
H14A | 0.6119 | 0.8516 | 0.4373 | 0.040* | |
H14B | 0.7449 | 0.8029 | 0.3834 | 0.040* | |
O1 | 0.4186 (4) | 0.8294 (3) | 0.36828 (10) | 0.0370 (6) | |
F1 | 0.0466 (3) | 0.5716 (3) | 0.13736 (8) | 0.0472 (6) | |
Br1 | 0.82479 (5) | 0.17116 (4) | 0.494648 (14) | 0.03340 (14) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0242 (17) | 0.046 (2) | 0.040 (2) | 0.0044 (16) | 0.0043 (15) | 0.0050 (18) |
C2 | 0.040 (2) | 0.056 (3) | 0.031 (2) | 0.0112 (19) | 0.0092 (16) | 0.0047 (19) |
C3 | 0.049 (2) | 0.030 (2) | 0.028 (2) | 0.0183 (17) | −0.0033 (18) | −0.0054 (16) |
C4 | 0.037 (2) | 0.026 (2) | 0.036 (2) | 0.0035 (15) | −0.0035 (17) | −0.0044 (16) |
C5 | 0.0331 (19) | 0.0271 (19) | 0.034 (2) | 0.0003 (15) | 0.0055 (16) | 0.0012 (15) |
C6 | 0.0274 (17) | 0.0232 (18) | 0.0316 (19) | 0.0038 (14) | 0.0022 (14) | 0.0021 (15) |
C7 | 0.0250 (17) | 0.031 (2) | 0.0277 (19) | −0.0014 (15) | 0.0053 (14) | −0.0019 (15) |
C8 | 0.0251 (17) | 0.0210 (18) | 0.0237 (18) | 0.0002 (14) | 0.0026 (13) | −0.0020 (14) |
C9 | 0.0272 (17) | 0.027 (2) | 0.0277 (19) | −0.0025 (14) | 0.0015 (14) | −0.0014 (14) |
C10 | 0.0296 (18) | 0.0182 (17) | 0.032 (2) | −0.0031 (14) | 0.0058 (15) | −0.0008 (14) |
C11 | 0.0278 (16) | 0.0277 (18) | 0.0220 (17) | 0.0078 (15) | −0.0002 (13) | −0.0012 (15) |
C12 | 0.0214 (16) | 0.028 (2) | 0.032 (2) | 0.0000 (14) | −0.0025 (14) | −0.0051 (15) |
C13 | 0.0306 (18) | 0.0206 (18) | 0.0270 (19) | −0.0013 (14) | 0.0054 (15) | −0.0037 (14) |
C14 | 0.0291 (19) | 0.025 (2) | 0.046 (2) | −0.0034 (14) | −0.0020 (17) | 0.0010 (16) |
O1 | 0.0387 (13) | 0.0231 (13) | 0.0484 (16) | −0.0017 (11) | −0.0072 (11) | 0.0028 (11) |
F1 | 0.0592 (14) | 0.0534 (14) | 0.0284 (12) | 0.0208 (10) | −0.0033 (10) | −0.0057 (10) |
Br1 | 0.0392 (2) | 0.0276 (2) | 0.0330 (2) | 0.00621 (16) | −0.00337 (14) | 0.00021 (16) |
C1—C2 | 1.387 (5) | C8—C13 | 1.380 (4) |
C1—C6 | 1.387 (4) | C8—C9 | 1.381 (4) |
C1—H1 | 0.9500 | C9—C10 | 1.392 (4) |
C2—C3 | 1.367 (5) | C9—H9 | 0.9500 |
C2—H2 | 0.9500 | C10—C11 | 1.381 (4) |
C3—C4 | 1.369 (5) | C10—H10 | 0.9500 |
C3—F1 | 1.375 (4) | C11—C12 | 1.389 (4) |
C4—C5 | 1.388 (4) | C11—Br1 | 1.903 (3) |
C4—H4 | 0.9500 | C12—C13 | 1.380 (4) |
C5—C6 | 1.385 (4) | C12—H12 | 0.9500 |
C5—H5 | 0.9500 | C13—C14 | 1.500 (4) |
C6—C7 | 1.513 (4) | C14—O1 | 1.428 (4) |
C7—O1 | 1.445 (3) | C14—H14A | 0.9900 |
C7—C8 | 1.509 (4) | C14—H14B | 0.9900 |
C7—H7 | 1.0000 | ||
C2—C1—C6 | 120.8 (3) | C13—C8—C7 | 109.4 (3) |
C2—C1—H1 | 119.6 | C9—C8—C7 | 129.7 (3) |
C6—C1—H1 | 119.6 | C8—C9—C10 | 119.1 (3) |
C3—C2—C1 | 118.0 (3) | C8—C9—H9 | 120.5 |
C3—C2—H2 | 121.0 | C10—C9—H9 | 120.5 |
C1—C2—H2 | 121.0 | C11—C10—C9 | 119.1 (3) |
C2—C3—C4 | 123.6 (3) | C11—C10—H10 | 120.4 |
C2—C3—F1 | 118.3 (3) | C9—C10—H10 | 120.4 |
C4—C3—F1 | 118.0 (3) | C10—C11—C12 | 122.3 (3) |
C3—C4—C5 | 117.3 (3) | C10—C11—Br1 | 119.3 (2) |
C3—C4—H4 | 121.3 | C12—C11—Br1 | 118.3 (2) |
C5—C4—H4 | 121.3 | C13—C12—C11 | 117.5 (3) |
C6—C5—C4 | 121.5 (3) | C13—C12—H12 | 121.3 |
C6—C5—H5 | 119.3 | C11—C12—H12 | 121.3 |
C4—C5—H5 | 119.3 | C8—C13—C12 | 121.1 (3) |
C5—C6—C1 | 118.7 (3) | C8—C13—C14 | 109.2 (3) |
C5—C6—C7 | 120.3 (3) | C12—C13—C14 | 129.7 (3) |
C1—C6—C7 | 121.0 (3) | O1—C14—C13 | 105.3 (2) |
O1—C7—C8 | 104.4 (2) | O1—C14—H14A | 110.7 |
O1—C7—C6 | 110.1 (2) | C13—C14—H14A | 110.7 |
C8—C7—C6 | 114.5 (2) | O1—C14—H14B | 110.7 |
O1—C7—H7 | 109.2 | C13—C14—H14B | 110.7 |
C8—C7—H7 | 109.2 | H14A—C14—H14B | 108.8 |
C6—C7—H7 | 109.2 | C14—O1—C7 | 111.5 (2) |
C13—C8—C9 | 120.8 (3) | ||
C6—C1—C2—C3 | 0.0 (5) | C13—C8—C9—C10 | −1.0 (5) |
C1—C2—C3—C4 | −0.1 (5) | C7—C8—C9—C10 | −178.7 (3) |
C1—C2—C3—F1 | 178.9 (3) | C8—C9—C10—C11 | 0.1 (4) |
C2—C3—C4—C5 | −0.1 (5) | C9—C10—C11—C12 | 0.5 (5) |
F1—C3—C4—C5 | −179.1 (3) | C9—C10—C11—Br1 | 179.3 (2) |
C3—C4—C5—C6 | 0.3 (5) | C10—C11—C12—C13 | −0.2 (5) |
C4—C5—C6—C1 | −0.4 (5) | Br1—C11—C12—C13 | −179.0 (2) |
C4—C5—C6—C7 | 179.7 (3) | C9—C8—C13—C12 | 1.3 (5) |
C2—C1—C6—C5 | 0.2 (5) | C7—C8—C13—C12 | 179.5 (3) |
C2—C1—C6—C7 | −179.9 (3) | C9—C8—C13—C14 | −177.4 (3) |
C5—C6—C7—O1 | −147.9 (3) | C7—C8—C13—C14 | 0.8 (3) |
C1—C6—C7—O1 | 32.2 (4) | C11—C12—C13—C8 | −0.8 (4) |
C5—C6—C7—C8 | 94.9 (3) | C11—C12—C13—C14 | 177.7 (3) |
C1—C6—C7—C8 | −85.0 (4) | C8—C13—C14—O1 | −3.6 (3) |
O1—C7—C8—C13 | 2.3 (3) | C12—C13—C14—O1 | 177.8 (3) |
C6—C7—C8—C13 | 122.7 (3) | C13—C14—O1—C7 | 5.2 (3) |
O1—C7—C8—C9 | −179.7 (3) | C8—C7—O1—C14 | −4.7 (3) |
C6—C7—C8—C9 | −59.3 (4) | C6—C7—O1—C14 | −128.1 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C9—H9···F1i | 0.95 | 2.54 | 3.324 (4) | 140 |
C14—H14B···F1ii | 0.99 | 2.52 | 3.265 (4) | 132 |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1, y+1/2, −z+1/2. |
Acknowledgements
We thank the EPSRC National Crystallography Service for data collection. HGA thanks the University of Mysore for provision of research facilities.
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