organic compounds
(4-Bromophenyl)(1H-indol-7-yl)methanone
aDepartment of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland, and bDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
*Correspondence e-mail: mkubicki@amu.edu.pl
In the crystal, the molecules of the title compound, C15H10BrNO, are connected into centrosymmetric dimers by pairs of N—H⋯O hydrogen bonds. The dihedral angle between the planes of indole ring system and benzene ring is 50.13 (5)°. The indole plane is significantly less twisted from the plane of the central C—C(=O)—C bridge than the benzene plane [dihedral angles = 15.51 (3) and 40.13 (7)°, respectively]. The bond angles within the benzene ring show an approximately additive effect of the influence of both substituents.
Related literature
For applications of indoles, see: Murphy et al. (1997); Gupta et al. (1982); Al-Soud et al. (2004); Shigenaga et al. (1993); Butera et al. (2001). For synthethic procedures, see: Robinson (1982); Walsh et al. (1984). For related crystal structures of 7-pyridylindoles, see: Mudadu et al. (2006). For the influence of the substituent on the geometry of the phenyl ring, see: Domenicano (1988). For a description of the Cambridge Structural Database, see: Allen (2002).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis Pro (Oxford Diffraction, 2009); cell CrysAlis Pro; data reduction: CrysAlis Pro; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536809040914/er2074sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536809040914/er2074Isup2.hkl
A mixture of (4-bromophenyl)(2,3-dihydro-1H-indol-7-yl)methanone (2.4 g, 7.9 m mol) and activated manganese dioxide (2.2 g, 25 m mol) in 100 ml dichloromethane was refluxed for 18 h (Fig. 3). The contents were filtered and the organic layer was concentrated. The product formed (Walsh et al., 1984) was crystallized from tetrahydrofuran (m.p.: 435 – 437 K).
The synthesis of indole derivatives has long been a topic of fundamental interest to organic and medicinal chemists (Murphy et al., 1997). Indole derivatives are important pharmacologically, possessing anti-allergic (Shigenaga et al., 1993), central-nervous-system depressant (Sen Gupta et al., 1982), muscle relaxant (Butera et al.,2001), and anti-cancer (Al-Soud et al.,2004) properties. The Fischer indole synthesis is the most widely used method for the preparation of indole derivatives (e.g., Robinson, 1982). The title compound (I) is an intermediate for preparation of bromofenac, which is used as analgesic.
There are only few crystal structures of 7-substituted indoles in the Cambridge Crystallographic Database (Allen, 2002). Recently, the crystal structures of three 7-pyridylindoles (Mudadu et al., 2006) have been reported.
The conformation of the molecule I can be described by the mutual orientation of the three approximately planar fragments (Fig. 1): indole system (maximum deviation from the least-squares plane of 0.0142 (7) Å), phenyl ring (maximum deviation 0.0145 (13) Å), and the central C—C(=O)—C bridge (0.0040 (16) Å). The dihedral angle between the terminal planes, of indole and phenyl fragments, is 50.13 (5)°, while it can be noted that the indole plane is less inclined with respect to the central bridge plane (15.51 (3)°) than is the phenyl one (40.13 (7)°). The geometry of the phenyl ring is affected by the presence of substituents; using the values given by Domenicano (1988) and obtained form the search of the CSD (Allen, 2002), it might be shown that the overall influence on the bond angles pattern is close to additivity of separate effects of both Br and COAr substituents.
In the π interactions.
the molecules of (I) are connected into the centrosymmetric, hydrogen bonded pairs - R22(12) motifs - by means of relatively strong and linear N—H···O hydrogen bonds (Fig. 2). These dimers are packed by means of van der Waals and weak C—H···For applications of indoles, see: Murphy et al. (1997); Gupta et al. (1982); Al-Soud et al. (2004); Shigenaga et al. (1993); Butera et al. (2001). For synthethic procedures, see: Robinson (1982); Walsh et al. (1984). For related crystal structures of 7-pyridylindoles, see: Mudadu et al. (2006). For the influence of the substituent on the geometry of the phenyl ring, see: Domenicano (1988). For a description of the Cambridge Structural Database, see: Allen (2002).
Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell
CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C15H10BrNO | F(000) = 600 |
Mr = 300.15 | Dx = 1.619 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 12183 reflections |
a = 11.3241 (4) Å | θ = 2.0–26.8° |
b = 7.4651 (3) Å | µ = 3.32 mm−1 |
c = 14.9579 (5) Å | T = 291 K |
β = 103.100 (4)° | Block, colourless |
V = 1231.57 (8) Å3 | 0.4 × 0.2 × 0.15 mm |
Z = 4 |
Oxford Diffraction Xcalibur (Sapphire2, large Be window) diffractometer | 2558 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 1864 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.036 |
Detector resolution: 8.1929 pixels mm-1 | θmax = 26.8°, θmin = 2.1° |
ω scans | h = −13→14 |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | k = −9→9 |
Tmin = 0.26, Tmax = 0.60 | l = −18→18 |
25357 measured 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)] = 0.024 | H-atom parameters constrained |
wR(F2) = 0.063 | w = 1/[σ2(Fo2) + (0.035P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
2558 reflections | Δρmax = 0.34 e Å−3 |
174 parameters | Δρmin = −0.29 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0139 (9) |
C15H10BrNO | V = 1231.57 (8) Å3 |
Mr = 300.15 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.3241 (4) Å | µ = 3.32 mm−1 |
b = 7.4651 (3) Å | T = 291 K |
c = 14.9579 (5) Å | 0.4 × 0.2 × 0.15 mm |
β = 103.100 (4)° |
Oxford Diffraction Xcalibur (Sapphire2, large Be window) diffractometer | 2558 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) | 1864 reflections with I > 2σ(I) |
Tmin = 0.26, Tmax = 0.60 | Rint = 0.036 |
25357 measured reflections |
R[F2 > 2σ(F2)] = 0.024 | 0 restraints |
wR(F2) = 0.063 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.34 e Å−3 |
2558 reflections | Δρmin = −0.29 e Å−3 |
174 parameters |
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 | ||
N1 | 0.28642 (14) | −0.0239 (2) | 0.94540 (10) | 0.0386 (4) | |
H1 | 0.3601 | −0.0274 | 0.9768 | 0.053 (6)* | |
C2 | 0.18656 (19) | −0.0579 (3) | 0.97896 (14) | 0.0459 (5) | |
H2 | 0.1876 | −0.0872 | 1.0396 | 0.043 (5)* | |
C3 | 0.08506 (18) | −0.0424 (3) | 0.91063 (14) | 0.0449 (5) | |
H3 | 0.0056 | −0.0604 | 0.9157 | 0.053 (6)* | |
C4 | 0.12356 (15) | 0.0064 (3) | 0.83002 (13) | 0.0344 (4) | |
C5 | 0.25153 (15) | 0.0167 (3) | 0.85411 (11) | 0.0315 (4) | |
C6 | 0.32088 (15) | 0.0562 (2) | 0.78996 (12) | 0.0314 (4) | |
C7 | 0.25687 (16) | 0.0912 (2) | 0.70024 (12) | 0.0353 (4) | |
H7 | 0.2995 | 0.1200 | 0.6559 | 0.035 (5)* | |
C8 | 0.13073 (17) | 0.0839 (2) | 0.67577 (13) | 0.0400 (5) | |
H8 | 0.0908 | 0.1083 | 0.6155 | 0.046 (6)* | |
C9 | 0.06422 (17) | 0.0413 (2) | 0.73904 (14) | 0.0387 (5) | |
H9 | −0.0199 | 0.0357 | 0.7215 | 0.053 (6)* | |
C10 | 0.45391 (16) | 0.0642 (2) | 0.81808 (12) | 0.0372 (4) | |
O10 | 0.50404 (12) | 0.0723 (2) | 0.90015 (9) | 0.0593 (5) | |
C11 | 0.53044 (15) | 0.0650 (2) | 0.74900 (12) | 0.0322 (4) | |
C12 | 0.50633 (16) | −0.0445 (2) | 0.67135 (13) | 0.0352 (4) | |
H12 | 0.4387 | −0.1188 | 0.6605 | 0.041 (6)* | |
C13 | 0.58143 (17) | −0.0438 (2) | 0.61058 (12) | 0.0371 (5) | |
H13 | 0.5656 | −0.1189 | 0.5596 | 0.035 (5)* | |
C14 | 0.68042 (16) | 0.0694 (3) | 0.62617 (12) | 0.0363 (4) | |
Br14 | 0.779765 (18) | 0.07710 (3) | 0.539996 (14) | 0.05633 (12) | |
C15 | 0.70737 (16) | 0.1777 (3) | 0.70285 (12) | 0.0389 (5) | |
H15 | 0.7746 | 0.2529 | 0.7129 | 0.051 (6)* | |
C16 | 0.63296 (15) | 0.1728 (3) | 0.76455 (12) | 0.0366 (4) | |
H16 | 0.6519 | 0.2428 | 0.8173 | 0.036 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0302 (9) | 0.0511 (11) | 0.0332 (8) | −0.0010 (8) | 0.0045 (7) | 0.0004 (7) |
C2 | 0.0452 (12) | 0.0568 (14) | 0.0390 (10) | −0.0020 (10) | 0.0167 (9) | −0.0002 (10) |
C3 | 0.0309 (11) | 0.0563 (14) | 0.0504 (12) | −0.0031 (10) | 0.0157 (9) | −0.0039 (10) |
C4 | 0.0294 (10) | 0.0291 (10) | 0.0446 (10) | 0.0011 (8) | 0.0080 (8) | −0.0049 (9) |
C5 | 0.0303 (10) | 0.0275 (10) | 0.0350 (10) | 0.0002 (8) | 0.0034 (7) | −0.0032 (8) |
C6 | 0.0268 (9) | 0.0303 (11) | 0.0353 (9) | −0.0016 (8) | 0.0032 (7) | −0.0017 (8) |
C7 | 0.0326 (10) | 0.0355 (11) | 0.0367 (10) | −0.0008 (9) | 0.0057 (8) | 0.0033 (8) |
C8 | 0.0348 (11) | 0.0415 (12) | 0.0387 (10) | 0.0027 (9) | −0.0020 (8) | 0.0028 (9) |
C9 | 0.0248 (10) | 0.0376 (12) | 0.0502 (11) | 0.0015 (8) | 0.0011 (8) | −0.0024 (9) |
C10 | 0.0320 (10) | 0.0415 (12) | 0.0358 (10) | −0.0035 (9) | 0.0028 (8) | 0.0037 (9) |
O10 | 0.0339 (8) | 0.1051 (14) | 0.0347 (7) | −0.0108 (8) | −0.0010 (6) | 0.0059 (8) |
C11 | 0.0240 (9) | 0.0341 (10) | 0.0353 (9) | 0.0015 (8) | −0.0004 (7) | 0.0034 (8) |
C12 | 0.0283 (10) | 0.0321 (12) | 0.0410 (10) | −0.0031 (8) | −0.0007 (8) | 0.0021 (8) |
C13 | 0.0354 (11) | 0.0350 (12) | 0.0363 (10) | 0.0059 (9) | −0.0015 (8) | −0.0007 (9) |
C14 | 0.0283 (10) | 0.0428 (12) | 0.0366 (9) | 0.0071 (9) | 0.0047 (8) | 0.0086 (9) |
Br14 | 0.04658 (16) | 0.0801 (2) | 0.04560 (15) | 0.00255 (12) | 0.01738 (10) | 0.00603 (11) |
C15 | 0.0268 (10) | 0.0424 (12) | 0.0454 (11) | −0.0057 (9) | 0.0034 (8) | −0.0012 (9) |
C16 | 0.0284 (10) | 0.0402 (12) | 0.0386 (10) | −0.0011 (9) | 0.0020 (8) | −0.0045 (9) |
N1—C2 | 1.361 (3) | C8—H8 | 0.9300 |
N1—C5 | 1.367 (2) | C9—H9 | 0.9300 |
N1—H1 | 0.8600 | C10—O10 | 1.232 (2) |
C2—C3 | 1.359 (3) | C10—C11 | 1.492 (2) |
C2—H2 | 0.9300 | C11—C16 | 1.388 (2) |
C3—C4 | 1.419 (3) | C11—C12 | 1.395 (3) |
C3—H3 | 0.9300 | C12—C13 | 1.378 (3) |
C4—C9 | 1.399 (3) | C12—H12 | 0.9300 |
C4—C5 | 1.414 (2) | C13—C14 | 1.381 (3) |
C5—C6 | 1.402 (2) | C13—H13 | 0.9300 |
C6—C7 | 1.398 (2) | C14—C15 | 1.380 (3) |
C6—C10 | 1.471 (2) | C14—Br14 | 1.8941 (18) |
C7—C8 | 1.393 (2) | C15—C16 | 1.384 (2) |
C7—H7 | 0.9300 | C15—H15 | 0.9300 |
C8—C9 | 1.374 (3) | C16—H16 | 0.9300 |
C2—N1—C5 | 109.49 (16) | C8—C9—C4 | 119.72 (17) |
C2—N1—H1 | 125.3 | C8—C9—H9 | 120.1 |
C5—N1—H1 | 125.3 | C4—C9—H9 | 120.1 |
C3—C2—N1 | 109.79 (18) | O10—C10—C6 | 119.87 (17) |
C3—C2—H2 | 125.1 | O10—C10—C11 | 118.77 (17) |
N1—C2—H2 | 125.1 | C6—C10—C11 | 121.36 (15) |
C2—C3—C4 | 106.88 (17) | C16—C11—C12 | 118.51 (17) |
C2—C3—H3 | 126.6 | C16—C11—C10 | 118.77 (16) |
C4—C3—H3 | 126.6 | C12—C11—C10 | 122.66 (16) |
C9—C4—C5 | 118.45 (17) | C13—C12—C11 | 120.89 (17) |
C9—C4—C3 | 134.58 (18) | C13—C12—H12 | 119.6 |
C5—C4—C3 | 106.97 (16) | C11—C12—H12 | 119.6 |
N1—C5—C6 | 130.57 (15) | C12—C13—C14 | 119.29 (17) |
N1—C5—C4 | 106.86 (16) | C12—C13—H13 | 120.4 |
C6—C5—C4 | 122.53 (15) | C14—C13—H13 | 120.4 |
C7—C6—C5 | 116.57 (16) | C15—C14—C13 | 121.14 (17) |
C7—C6—C10 | 122.80 (16) | C15—C14—Br14 | 119.62 (14) |
C5—C6—C10 | 120.61 (15) | C13—C14—Br14 | 119.24 (14) |
C8—C7—C6 | 121.52 (17) | C14—C15—C16 | 119.04 (18) |
C8—C7—H7 | 119.2 | C14—C15—H15 | 120.5 |
C6—C7—H7 | 119.2 | C16—C15—H15 | 120.5 |
C9—C8—C7 | 121.18 (17) | C15—C16—C11 | 121.07 (18) |
C9—C8—H8 | 119.4 | C15—C16—H16 | 119.5 |
C7—C8—H8 | 119.4 | C11—C16—H16 | 119.5 |
C5—N1—C2—C3 | 0.7 (2) | C3—C4—C9—C8 | −179.0 (2) |
N1—C2—C3—C4 | −0.8 (2) | C7—C6—C10—O10 | 163.69 (18) |
C2—C3—C4—C9 | 179.9 (2) | C5—C6—C10—O10 | −14.7 (3) |
C2—C3—C4—C5 | 0.6 (2) | C7—C6—C10—C11 | −15.5 (3) |
C2—N1—C5—C6 | −178.08 (19) | C5—C6—C10—C11 | 166.12 (17) |
C2—N1—C5—C4 | −0.3 (2) | O10—C10—C11—C16 | −37.9 (3) |
C9—C4—C5—N1 | −179.61 (17) | C6—C10—C11—C16 | 141.34 (18) |
C3—C4—C5—N1 | −0.2 (2) | O10—C10—C11—C12 | 139.08 (19) |
C9—C4—C5—C6 | −1.6 (3) | C6—C10—C11—C12 | −41.7 (3) |
C3—C4—C5—C6 | 177.79 (17) | C16—C11—C12—C13 | −1.0 (3) |
N1—C5—C6—C7 | 179.52 (18) | C10—C11—C12—C13 | −177.97 (16) |
C4—C5—C6—C7 | 2.0 (3) | C11—C12—C13—C14 | −1.2 (3) |
N1—C5—C6—C10 | −2.0 (3) | C12—C13—C14—C15 | 2.0 (3) |
C4—C5—C6—C10 | −179.52 (18) | C12—C13—C14—Br14 | −177.47 (13) |
C5—C6—C7—C8 | −1.1 (3) | C13—C14—C15—C16 | −0.4 (3) |
C10—C6—C7—C8 | −179.52 (17) | Br14—C14—C15—C16 | 179.00 (14) |
C6—C7—C8—C9 | −0.2 (3) | C14—C15—C16—C11 | −1.9 (3) |
C7—C8—C9—C4 | 0.7 (3) | C12—C11—C16—C15 | 2.5 (3) |
C5—C4—C9—C8 | 0.2 (3) | C10—C11—C16—C15 | 179.66 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O10i | 0.86 | 2.14 | 2.935 (2) | 153 |
Symmetry code: (i) −x+1, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C15H10BrNO |
Mr | 300.15 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 291 |
a, b, c (Å) | 11.3241 (4), 7.4651 (3), 14.9579 (5) |
β (°) | 103.100 (4) |
V (Å3) | 1231.57 (8) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 3.32 |
Crystal size (mm) | 0.4 × 0.2 × 0.15 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur (Sapphire2, large Be window) |
Absorption correction | Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009) |
Tmin, Tmax | 0.26, 0.60 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 25357, 2558, 1864 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.635 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.024, 0.063, 1.06 |
No. of reflections | 2558 |
No. of parameters | 174 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.34, −0.29 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2009), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 2008), Stereochemical Workstation Operation Manual (Siemens, 1989).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O10i | 0.86 | 2.14 | 2.935 (2) | 153.3 |
Symmetry code: (i) −x+1, −y, −z+2. |
Acknowledgements
CSC thanks the University of Mysore for research facilities.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The synthesis of indole derivatives has long been a topic of fundamental interest to organic and medicinal chemists (Murphy et al., 1997). Indole derivatives are important pharmacologically, possessing anti-allergic (Shigenaga et al., 1993), central-nervous-system depressant (Sen Gupta et al., 1982), muscle relaxant (Butera et al.,2001), and anti-cancer (Al-Soud et al.,2004) properties. The Fischer indole synthesis is the most widely used method for the preparation of indole derivatives (e.g., Robinson, 1982). The title compound (I) is an intermediate for preparation of bromofenac, which is used as analgesic.
There are only few crystal structures of 7-substituted indoles in the Cambridge Crystallographic Database (Allen, 2002). Recently, the crystal structures of three 7-pyridylindoles (Mudadu et al., 2006) have been reported.
The conformation of the molecule I can be described by the mutual orientation of the three approximately planar fragments (Fig. 1): indole system (maximum deviation from the least-squares plane of 0.0142 (7) Å), phenyl ring (maximum deviation 0.0145 (13) Å), and the central C—C(=O)—C bridge (0.0040 (16) Å). The dihedral angle between the terminal planes, of indole and phenyl fragments, is 50.13 (5)°, while it can be noted that the indole plane is less inclined with respect to the central bridge plane (15.51 (3)°) than is the phenyl one (40.13 (7)°). The geometry of the phenyl ring is affected by the presence of substituents; using the values given by Domenicano (1988) and obtained form the search of the CSD (Allen, 2002), it might be shown that the overall influence on the bond angles pattern is close to additivity of separate effects of both Br and COAr substituents.
In the crystal structure the molecules of (I) are connected into the centrosymmetric, hydrogen bonded pairs - R22(12) motifs - by means of relatively strong and linear N—H···O hydrogen bonds (Fig. 2). These dimers are packed by means of van der Waals and weak C—H···π interactions.