2-[(4-tert-Butyl­anilino)(phen­yl)meth­yl]cyclo­hexa­none

Hoong-Kun Fun; Suchada Chantrapromma; Sankappa Rai; Prakash Shetty; Arun M Isloor

doi:10.1107/S1600536809004954

. 2009 Feb 18;65(Pt 3):o539–o540. doi: 10.1107/S1600536809004954

2-[(4-tert-Butylanilino)(phenyl)methyl]cyclohexanone

Hoong-Kun Fun ^a,^*, Suchada Chantrapromma ^b,^‡, Sankappa Rai ^c, Prakash Shetty ^d, Arun M Isloor ^e

PMCID: PMC2968565 PMID: 21582199

Abstract

In the molecule of the title compound, C₂₃H₂₉NO, the cyclohexanone ring has been distorted from the standard chair conformation by the ketone group such that part of the ring is almost flat. The remaining [(4-tert-butylanilino)(phenyl)methyl] portion of the molecule is in an equatorial position on the cyclohexanone ring. The dihedral angle between the two benzene rings is 81.52 (8)°. In the crystal packing, molecules are linked by N—H⋯O hydrogen bonds into infinite one-dimensional chains along the a axis and these chains are stacked down the c axis. The crystal structure is further stabilized by weak C—H⋯O and C—H⋯π interactions.

Related literature

For values of bond lengths, see: Allen et al. (1987 ▶). For details of hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For information on the Mannich reaction, see: Kobayashi & Ishitani (1999 ▶); Bohme & Haake (1976 ▶). For background to the bioactivity and applications of beta-amino carbonyl compounds, see, for example: Arend et al. (1988 ▶); Isloor, Sunil et al. (2009 ▶); Isloor, Kalluraya et al. (2009 ▶); Jadhav et al. (2008 ▶); Kalluraya et al. (2001 ▶). For puckering parameters, see: Cremer & Pople, (1975 ▶). For the stability of the temperature controller, see Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₃H₂₉NO
M _r = 335.47
Triclinic,
a = 6.5315 (2) Å
b = 12.3946 (3) Å
c = 12.8853 (3) Å
α = 62.973 (1)°
β = 86.347 (2)°
γ = 85.103 (2)°
V = 925.46 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 100 K
0.52 × 0.41 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.953, T _max = 0.992
17722 measured reflections
4449 independent reflections
3584 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.124
S = 1.07
4449 reflections
233 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809004954/sj2573sup1.cif

e-65-0o539-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809004954/sj2573Isup2.hkl

e-65-0o539-Isup2.hkl^{(218KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N1⋯O1ⁱ	0.89 (2)	2.35 (2)	3.2050 (16)	161.6 (19)
C9—H9A⋯O1	0.93	2.59	3.1146 (19)	116
C2—H2A⋯Cg1ⁱⁱ	0.97	2.60	3.4992 (19)	155
C23—H23C⋯Cg1ⁱⁱⁱ	0.96	2.99	3.747 (2)	137

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the C14–C19 ring.

Acknowledgments

AMI is grateful to the Director, NITK, Surathkal, India, for providing research facilities. SR thanks Dr Gautam Das, Syngene International Ltd, Bangalore, India, for allocation of research resources. The authors also thank the Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

supplementary crystallographic information

Comment

Mannich reactions are among the most important carbon-carbon bond forming reactions in organic synthesis (Kobayashi & Ishitani, 1999). They provide beta-amino carbonyl compounds, which are important synthetic intermediates for various pharmaceuticals and natural products (Arend et al., 1988). They exhibit wide variety of pharmaceutical properties such as anti cancer (Isloor, Sunil et al., 2009), analgesic (Isloor, Kalluraya et al., 2009), anti-inflammatory (Jadhav et al., 2008), antimicrobial (Kalluraya et al., 2001) activities. The increasing popularity of the Mannich reaction has been fueled by the ubiquitous nature of nitrogen containing compounds in drugs and natural products (Bohme & Haake, 1976). Prompted by the biological activity of these derivatives, we have synthesized the title compound (I) and report its structure here, Fig 1. The cyclohexanone ring has been distorted from the standard chair conformation by the ketone group such that the C2 C1 O1 C6 part of the ring is almost flat with puckering parameter Q = 0.5181 (16)Å, and θ = 159.23 (18)° and φ = 9.3 (5)° (Cremer & Pople, 1975). The [4-(tert-butyl)anilino](phenyl)methyl substituent group is equatorially attached to the ring at atom C6 with torsion angles C5–C6–C7–C8 = -57.80 (16)° and C5–C6–C7–N1 = 69.13 (15)°. The two benzene rings are nearly perpendicular to each other with a dihedral angle of 81.52 (8)° between them. The bond distances have normal values (Allen et al., 1987).

A weak intramolecular C9—H9A···O1 interaction generates an S(7) ring motif (Bernstein et al., 1995) (Table 1) and effects the solid state conformation of the molecule. In the crystal structure N—H···O hydrogen bonds (Table 1, Fig. 2) link the molecules into infinite one-dimensional chains along the a axis and these chains are stacked down the c axis. The crystal is further stabilized by weak C—H···O and C—H···π interactions (Table 1); Cg1 is the centroid of the C14–C19 ring (Table 1).

Experimental

The title compound was obtained by vigorously stirring a solution of cyclohexanone (0.5 g, 5.0 mmol), benzaldehyde (0.53 g, 5.0 mmol) and 4-tert-butylaniline (0.75 g, 5.0 mmol) in dry acetonitrile (5 ml). Trifluoro acetic acid (0.57 g, 5 mmol) was then added. The reaction mixture was stirred at room temperature for 2 h. After standing for 1 hr, the solvent was removed and the crude product was purified by column chromatography using ethyl acetate and petroleum ether (1:1 v:v) as eluants. The product was further recrystalized using 10 ml of hot ethanol. The yield was 1 g (58%), M.p 439–441 K.