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Acta Crystallogr Sect E Struct Rep Online. 2010 May 1; 66(Pt 5): o1107.
Published online 2010 April 17. doi:  10.1107/S1600536810013371
PMCID: PMC2979094

1,2-Diphenyl-2-(m-tolyl­amino)ethanone1

Abstract

The title compound, C21H19NO, belongs to the family of α-amino­ketones. The structure contains three benzene rings, two of which [the phenyl ring in the 1-position (B) and the methylaniline ring (A)] are nearly coplanar [dihedral angle = 5.4 (1)°], whereas the phenyl ring in the 2-position (C) is nearly normal to them [dihedral angles = 81.8 (1) and 87.0 (1)° for A/C and B/C, respectively]. The conformation of the N—H bond is syn to the C=O bond, favouring the formation of a centrosymmetric dimer of mol­ecules in the crystal structure. The mol­ecular packing is consolidated by this N—H(...)O hydrogen-bonding network.

Related literature

For the structure of alpha-amino­ketones, see: Batsanov et al. (2006 [triangle]). For the crystal structure of 1,2-diphenyl-2-(p-tolyl­amino)ethanone, see: Au & Tafeenko (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1107-scheme1.jpg

Experimental

Crystal data

  • C21H19NO
  • M r = 301.37
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1107-efi1.jpg
  • a = 6.0510 (3) Å
  • b = 11.5745 (4) Å
  • c = 12.9458 (7) Å
  • α = 112.542 (5)°
  • β = 97.396 (4)°
  • γ = 99.960 (4)°
  • V = 805.62 (8) Å3
  • Z = 2
  • Cu Kα radiation
  • μ = 0.59 mm−1
  • T = 293 K
  • 0.34 × 0.12 × 0.07 mm

Data collection

  • Oxford Diffraction Xcalibur Gemini S diffractometer
  • Absorption correction: refined from ΔF [cubic fit to sin(theta)/lambda - 24 parameters; Parkin et al. (1995 [triangle])] T min = 0.919, T max = 0.960
  • 8027 measured reflections
  • 2833 independent reflections
  • 2174 reflections with I > 2σ(I)
  • R int = 0.027

Refinement

  • R[F 2 > 2σ(F 2)] = 0.043
  • wR(F 2) = 0.137
  • S = 1.09
  • 2833 reflections
  • 213 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.25 e Å−3
  • Δρmin = −0.16 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: SIR92 (Altomare et al., 1994 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]) and PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810013371/su2170sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810013371/su2170Isup2.hkl

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

Acknowledgments

Financial support by the Agencia Española de Cooperación Inter­nacional y Desarrollo (AECID), FEDER funding, the Spanish MICINN (MAT2006–01997 and Factoría de Cristalización Consolider Ingenio 2010) and the Gobierno del Principado de Asturias (PCTI) is acknowledged. Special acknowledgements go to Professor José Manuel Concellón for his support and scientific advice.

supplementary crystallographic information

Comment

The structure of various members of the alpha-aminoketone family have been extensively studied (Batsanov et al., 2006). These compounds can be used as intermediates to synthesize other biologically active compounds like thiosemicarbazones. Alpha-aminoketones also exhibit biological activity but are less active than the thiosemicarbazones. They are generally synthesised by the reaction of an alpha-hydroxiketone with an amine.

The molecular structure of the title molecule is illustrated in Fig. 1. According to the dihedral angles between the benzene rings planes, two benzene rings are nearly coplanar whereas the central ring is almost normal to them (5.3 (1)° for A/B, 81.8 (1)° for A/C and 87.0 (1)° for B/C). Comparing these values with those in the similar structure where the methyl subtitutent is in the para position (5.1° for A/B, 86.28° for A/C and 84.19° for B/C), there are no noticeable differences (Au & Tafeenko, 1986).

In the crystal structure, the molecular packing is made up of a network of weak hydrogen-bonding interactions (Fig. 2 & Table 1), favouring the formation of centrosymmetric dimers. Such conformations bring the C═O and N—H bonds into a syn orientation. The intermolecular distance between the centroids of the parallel benzene rings is ca. 3.77 Å. This value suggests the absence of any relevant π-stacking interactions.

Experimental

0.0235 mol benzoin, 0.0235 mol 3-methylaniline and 0.0235 mol boric acid were added to 10 ml of ethyleneglycol. The mixture was heated to reflux for 1 h, then 15 ml of ethanol were added and the mixture cooled to RT. The reaction was followed using TLC. The yellow precipitate obtained was washed with cold water and ethanol (yield 85%). Yellow needle-like crystals, suitable for x-ray diffraction analysis, were obtained after a week by slow evaporation of a solution in ethanol.

Refinement

The NH H-atom was located in difference electron-density map and was freely refined: N-H = 0.858 (17) Å. The C-bound H-atoms were included in calculated positions and treated as riding atoms: C-H = 0.98 Å, 0.93 Å and 0.96 Å for tertiary CH, aromatic CH and CH3 H-atoms, respectively, with Uiso(H) = k × Ueq(C), where k = 1.2 for CH H-atoms, and 1.5 for CH3 H-atoms.

Figures

Fig. 1.
A view of the molecular structure of the title molecule showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2.
A view along the a-axis of the crystal packing of the title compound. Hydrogen bonds are indicated by dashed lines (see Table 1 for details).

Crystal data

C21H19NOZ = 2
Mr = 301.37F(000) = 320
Triclinic, P1Dx = 1.242 Mg m3
Hall symbol: -P 1Melting point: 385.14 K
a = 6.0510 (3) ÅCu Kα radiation, λ = 1.54184 Å
b = 11.5745 (4) ÅCell parameters from 4346 reflections
c = 12.9458 (7) Åθ = 3.8–66.7°
α = 112.542 (5)°µ = 0.59 mm1
β = 97.396 (4)°T = 293 K
γ = 99.960 (4)°Needle, yellow
V = 805.62 (8) Å30.34 × 0.12 × 0.07 mm

Data collection

Oxford Diffraction Xcalibur Gemini S diffractometer2833 independent reflections
Radiation source: Enhance (Cu) X-ray Source2174 reflections with I > 2σ(I)
graphiteRint = 0.027
Detector resolution: 16.0827 pixels mm-1θmax = 66.7°, θmin = 3.8°
ω scansh = −6→7
Absorption correction: part of the refinement model (ΔF) [cubic fit to sin(theta)/lambda - 24 parameters; Parkin et al. (1995)]k = −10→13
Tmin = 0.919, Tmax = 0.960l = −15→14
8027 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.043H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.137w = 1/[σ2(Fo2) + (0.0863P)2] where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
2833 reflectionsΔρmax = 0.25 e Å3
213 parametersΔρmin = −0.16 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0041 (11)

Special details

Experimental. 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 > 2sigma(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.
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles
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
O10.52659 (18)0.50924 (11)0.14596 (9)0.0662 (4)
N10.1300 (2)0.38301 (13)0.00199 (11)0.0529 (4)
C10.6200 (3)0.63202 (19)0.38272 (15)0.0714 (6)
C20.6620 (4)0.6946 (2)0.50033 (17)0.0880 (8)
C30.4898 (4)0.6891 (2)0.55688 (17)0.0847 (8)
C40.2717 (4)0.6232 (2)0.49658 (17)0.0863 (8)
C50.2260 (3)0.56261 (18)0.37817 (15)0.0707 (6)
C60.4006 (3)0.56467 (14)0.31949 (13)0.0497 (5)
C70.3671 (2)0.49865 (14)0.19224 (13)0.0480 (5)
C80.1322 (2)0.41085 (13)0.12058 (12)0.0452 (4)
C90.0958 (2)0.28933 (13)0.14383 (11)0.0454 (4)
C10−0.0802 (3)0.25707 (16)0.19337 (14)0.0586 (5)
C11−0.1102 (3)0.14576 (19)0.21171 (17)0.0757 (7)
C120.0364 (4)0.06604 (19)0.18093 (18)0.0819 (7)
C130.2102 (3)0.09623 (17)0.13051 (17)0.0742 (7)
C140.2411 (3)0.20731 (15)0.11226 (14)0.0574 (5)
C15−0.0560 (2)0.30252 (13)−0.08485 (12)0.0452 (4)
C16−0.2728 (3)0.26933 (15)−0.06433 (14)0.0540 (5)
C17−0.4522 (3)0.18600 (16)−0.15360 (14)0.0597 (6)
C18−0.4218 (3)0.13398 (16)−0.26408 (15)0.0633 (6)
C19−0.2086 (3)0.16684 (16)−0.28761 (14)0.0578 (5)
C20−0.0286 (3)0.25155 (14)−0.19799 (13)0.0510 (5)
C21−0.1709 (4)0.1084 (2)−0.40766 (16)0.0896 (8)
H10.740800.635100.345400.0860*
H20.810000.741000.541300.1060*
H30.520000.730000.636400.1020*
H40.153300.619000.535200.1040*
H50.076100.520100.337800.0850*
H80.011800.455800.144100.0540*
H10−0.179600.310800.214600.0700*
H11−0.229700.124800.244900.0910*
H120.01770−0.008100.194300.0980*
H130.307900.041600.108500.0890*
H140.360200.227300.078500.0690*
H16−0.297000.303400.009800.0650*
H17−0.596400.16470−0.138700.0720*
H18−0.544100.07680−0.323000.0760*
H200.114000.27500−0.213600.0610*
H21A−0.312500.05270−0.458500.1340*
H21B−0.057300.05940−0.409900.1340*
H21C−0.118600.17570−0.431200.1340*
H220.262 (3)0.4037 (17)−0.0130 (15)0.062 (5)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0533 (7)0.0727 (8)0.0548 (7)−0.0058 (6)0.0118 (5)0.0167 (6)
N10.0473 (7)0.0602 (8)0.0438 (7)0.0004 (6)0.0051 (6)0.0207 (6)
C10.0584 (10)0.0864 (13)0.0546 (10)0.0023 (9)0.0014 (8)0.0235 (9)
C20.0714 (12)0.1108 (17)0.0540 (11)−0.0008 (11)−0.0099 (10)0.0220 (11)
C30.1014 (16)0.0868 (14)0.0459 (10)0.0088 (12)0.0028 (10)0.0164 (10)
C40.0896 (14)0.0886 (14)0.0559 (11)0.0028 (12)0.0230 (10)0.0096 (10)
C50.0637 (10)0.0698 (11)0.0536 (10)0.0000 (9)0.0116 (8)0.0066 (9)
C60.0528 (8)0.0442 (8)0.0467 (8)0.0051 (6)0.0043 (7)0.0180 (7)
C70.0482 (8)0.0424 (8)0.0495 (9)0.0043 (6)0.0072 (7)0.0189 (7)
C80.0449 (7)0.0435 (7)0.0419 (8)0.0067 (6)0.0063 (6)0.0148 (6)
C90.0449 (7)0.0429 (8)0.0373 (7)0.0024 (6)−0.0008 (6)0.0114 (6)
C100.0547 (9)0.0597 (9)0.0553 (10)0.0018 (7)0.0080 (7)0.0239 (8)
C110.0766 (12)0.0717 (12)0.0716 (13)−0.0114 (10)0.0029 (10)0.0387 (10)
C120.0939 (14)0.0551 (10)0.0810 (14)−0.0101 (10)−0.0212 (11)0.0360 (10)
C130.0802 (12)0.0503 (10)0.0758 (12)0.0156 (9)−0.0107 (10)0.0177 (9)
C140.0583 (9)0.0513 (9)0.0527 (9)0.0100 (7)0.0032 (7)0.0152 (7)
C150.0466 (8)0.0422 (7)0.0455 (8)0.0090 (6)0.0030 (6)0.0199 (6)
C160.0487 (8)0.0590 (9)0.0502 (9)0.0106 (7)0.0078 (7)0.0202 (7)
C170.0452 (8)0.0632 (10)0.0640 (11)0.0057 (7)0.0031 (7)0.0253 (9)
C180.0583 (10)0.0554 (9)0.0591 (10)0.0013 (8)−0.0093 (8)0.0178 (8)
C190.0662 (10)0.0531 (9)0.0479 (9)0.0111 (7)0.0037 (7)0.0187 (7)
C200.0531 (8)0.0517 (8)0.0481 (9)0.0092 (7)0.0085 (7)0.0230 (7)
C210.0968 (15)0.0917 (15)0.0515 (11)0.0013 (12)0.0072 (10)0.0113 (10)

Geometric parameters (Å, °)

O1—C71.2123 (18)C17—C181.374 (2)
N1—C81.4405 (19)C18—C191.386 (3)
N1—C151.3810 (19)C19—C201.388 (2)
N1—H220.862 (19)C19—C211.505 (3)
C1—C61.383 (3)C1—H10.9300
C1—C21.378 (3)C2—H20.9300
C2—C31.355 (3)C3—H30.9300
C3—C41.365 (3)C4—H40.9300
C4—C51.385 (3)C5—H50.9300
C5—C61.381 (3)C8—H80.9800
C6—C71.495 (2)C10—H100.9300
C7—C81.534 (2)C11—H110.9300
C8—C91.534 (2)C12—H120.9300
C9—C141.388 (2)C13—H130.9300
C9—C101.381 (2)C14—H140.9300
C10—C111.383 (3)C16—H160.9300
C11—C121.375 (3)C17—H170.9300
C12—C131.371 (3)C18—H180.9300
C13—C141.380 (3)C20—H200.9300
C15—C201.398 (2)C21—H21A0.9600
C15—C161.390 (2)C21—H21B0.9600
C16—C171.380 (2)C21—H21C0.9600
C8—N1—C15122.36 (13)C6—C1—H1120.00
C8—N1—H22115.3 (12)C1—C2—H2120.00
C15—N1—H22120.7 (12)C3—C2—H2120.00
C2—C1—C6120.89 (18)C2—C3—H3120.00
C1—C2—C3120.6 (2)C4—C3—H3120.00
C2—C3—C4119.66 (19)C3—C4—H4120.00
C3—C4—C5120.3 (2)C5—C4—H4120.00
C4—C5—C6120.71 (18)C4—C5—H5120.00
C1—C6—C7118.15 (15)C6—C5—H5120.00
C1—C6—C5117.76 (15)N1—C8—H8109.00
C5—C6—C7124.08 (15)C7—C8—H8109.00
O1—C7—C8119.84 (13)C9—C8—H8109.00
O1—C7—C6120.53 (14)C9—C10—H10120.00
C6—C7—C8119.55 (13)C11—C10—H10120.00
N1—C8—C9112.77 (13)C10—C11—H11120.00
C7—C8—C9107.94 (12)C12—C11—H11120.00
N1—C8—C7108.31 (12)C11—C12—H12120.00
C10—C9—C14118.55 (16)C13—C12—H12120.00
C8—C9—C10122.18 (13)C12—C13—H13120.00
C8—C9—C14119.26 (13)C14—C13—H13120.00
C9—C10—C11120.72 (17)C9—C14—H14120.00
C10—C11—C12120.06 (19)C13—C14—H14120.00
C11—C12—C13119.8 (2)C15—C16—H16120.00
C12—C13—C14120.36 (19)C17—C16—H16120.00
C9—C14—C13120.52 (16)C16—C17—H17119.00
C16—C15—C20117.97 (14)C18—C17—H17119.00
N1—C15—C16122.36 (13)C17—C18—H18120.00
N1—C15—C20119.68 (13)C19—C18—H18120.00
C15—C16—C17120.25 (15)C15—C20—H20119.00
C16—C17—C18121.25 (17)C19—C20—H20119.00
C17—C18—C19119.89 (17)C19—C21—H21A109.00
C18—C19—C20118.88 (16)C19—C21—H21B109.00
C18—C19—C21120.58 (17)C19—C21—H21C110.00
C20—C19—C21120.51 (17)H21A—C21—H21B109.00
C15—C20—C19121.73 (16)H21A—C21—H21C110.00
C2—C1—H1120.00H21B—C21—H21C109.00
C15—N1—C8—C7177.87 (14)N1—C8—C9—C1455.51 (17)
C15—N1—C8—C958.48 (18)C7—C8—C9—C10117.19 (14)
C8—N1—C15—C1617.0 (2)C7—C8—C9—C14−64.09 (16)
C8—N1—C15—C20−162.92 (15)C8—C9—C10—C11179.09 (15)
C6—C1—C2—C31.5 (4)C14—C9—C10—C110.4 (2)
C2—C1—C6—C50.1 (3)C8—C9—C14—C13−178.99 (15)
C2—C1—C6—C7−179.82 (19)C10—C9—C14—C13−0.2 (2)
C1—C2—C3—C4−1.4 (4)C9—C10—C11—C120.2 (3)
C2—C3—C4—C5−0.3 (4)C10—C11—C12—C13−1.0 (3)
C3—C4—C5—C61.9 (4)C11—C12—C13—C141.1 (3)
C4—C5—C6—C1−1.8 (3)C12—C13—C14—C9−0.5 (3)
C4—C5—C6—C7178.17 (19)N1—C15—C16—C17−178.40 (17)
C1—C6—C7—O1−3.4 (3)C20—C15—C16—C171.5 (3)
C1—C6—C7—C8173.22 (17)N1—C15—C20—C19177.80 (17)
C5—C6—C7—O1176.72 (18)C16—C15—C20—C19−2.2 (3)
C5—C6—C7—C8−6.7 (3)C15—C16—C17—C180.1 (3)
O1—C7—C8—N1−16.0 (2)C16—C17—C18—C19−1.1 (3)
O1—C7—C8—C9106.37 (17)C17—C18—C19—C200.5 (3)
C6—C7—C8—N1167.39 (14)C17—C18—C19—C21178.57 (19)
C6—C7—C8—C9−70.22 (17)C18—C19—C20—C151.1 (3)
N1—C8—C9—C10−123.21 (14)C21—C19—C20—C15−176.92 (18)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H22···O1i0.859 (17)2.660 (17)3.3913 (17)143.8 (15)

Symmetry codes: (i) −x+1, −y+1, −z.

Footnotes

1Dedicated to the memory of Professor José Manuel Concellón.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SU2170).

References

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  • Au, O. & Tafeenko, V. (1986). Rev. Cubana Quim.2, 65–74.
  • Batsanov, A. S., Goeta, A. E., Howard, J. A. K., Soto, B. & Au-Alvarez, O. (2006). Acta Cryst. C62, o304–o306. [PubMed]
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED Oxford Diffraction Ltd, Yarnton, England.
  • Parkin, S., Moezzi, B. & Hope, H. (1995). J. Appl. Cryst.28, 53–56.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]

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