3-Anilino-5,5-di­methyl­cyclo­hex-2-enone

Houssem Boulebd; Abdelmalek Bouraiou; Sofiane Bouacida; Hocine Merazig; Ali Belfaitah

doi:10.1107/S160053681400186X

. 2014 Feb 5;70(Pt 3):o233–o234. doi: 10.1107/S160053681400186X

3-Anilino-5,5-dimethylcyclohex-2-enone

Houssem Boulebd ^a, Abdelmalek Bouraiou ^a, Sofiane Bouacida ^b,^c,^*, Hocine Merazig ^b, Ali Belfaitah ^a

PMCID: PMC3998468 PMID: 24764957

Abstract

In the title molecule, C₁₄H₁₇NO, the 5,5-dimethylcyclohex-2-enone moiety is attached to an aniline group, the dihedral angle subtended [54.43 (3)°] indicating a significant twist. The hexaneone ring has a half-chair conformation with the C atom bearing two methyl groups lying 0.6384 (8) Å above the plane of the five remaining atoms (r.m.s. deviation = 0.0107 Å). The crystal packing can be described as alternating layers parallel to (-101), which are consolidated by N—H⋯O hydrogen bonds and C—H⋯π interactions.

Related literature

For the synthesis of the title compound, see: Amini et al. (2013 ▶); Machacek et al. (2002 ▶). For its reactivity, see: Wang et al. (2007 ▶); Mohammadizadeh et al. (2009 ▶); Gao et al. (2008 ▶). For our previous work [inspired by Assy (1996 ▶)] on the preparation and the reactivity of imidazole derivatives, see: Zama et al. (2013a ▶,b ▶); Chelghoum et al. (2011 ▶); Bahnous et al. (2012 ▶) For enamine derivatives as precursors in the synthesis ofcompounds of pharmaceutical interest, see: Palko et al. (2008 ▶) Park & Jahng (1998 ▶); Tadesse et al. (1999 ▶); Thummel & Jahng (1985 ▶); When enamines are treated with alkyl halides, an alkylation occurs to give an iminium salt, see: Adams (2000 ▶); Kempf et al. (2003 ▶).

Experimental

Crystal data

C₁₄H₁₇NO
M _r = 215.29
Monoclinic,
a = 10.1766 (19) Å
b = 13.159 (2) Å
c = 9.2877 (17) Å
β = 104.062 (7)°
V = 1206.5 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 150 K
0.15 × 0.12 × 0.09 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2002 ▶) T _min = 0.667, T _max = 0.747
12403 measured reflections
5021 independent reflections
3873 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.138
S = 1.04
5021 reflections
147 parameters
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and DIAMOND (Brandenburg & Berndt, 2001 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and CRYSCAL (T. Roisnel, local program).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S160053681400186X/bq2392sup1.cif

e-70-0o233-sup1.cif^{(22.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681400186X/bq2392Isup2.hkl

e-70-0o233-Isup2.hkl^{(240.9KB, hkl)}

Click here for additional data file.^{(4.8KB, cml)}

Supporting information file. DOI: 10.1107/S160053681400186X/bq2392Isup3.cml

CCDC reference: http://scripts.iucr.org/cgi-bin/cr.cgi?rm=csd&csdid=983637

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

Cg1 is the centroid of C10–C15 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1ⁱ	0.86	2.02	2.8587 (11)	165
C8—H8A⋯Cg1ⁱⁱ	0.96	2.61	3.5547 (12)	157

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

Thanks are due to MESRS (Ministére de l’Enseignement Supérieur et de la Recherche Scientifique - Algeria) for financial support.

supplementary crystallographic information

1. Comment

The reaction of primary amines with ketones leads to imines; however, secondary amines give enamines. The preparation of enamines takes place when an aldehyde or ketone containing an α hydrogen is treated with a secondary amine. When enamines are treated with alkyl halides, an alkylation occurs to give an iminium salt via an electron transfer from the electron pair on nitrogen, through the C=C to the electrophilic carbon of the alkyl halide (Adams, 2000). In fact, an enamine behaves as a "nitrogen enolate" and generally react as carbon nucleophiles (Kempf et al., 2003). The use of enamine derivatives as intermediates in organic synthesis has been extensively investigated and they proved to be versatile precursors in the synthesis of a large variety of compounds of pharmaceutical interest (Tadesse et al., 1999; Park et al., 1998; Thummel & Jahng 1985; Palko et al., 2008). Inspired by the works of Assy 1996 and also as an extension of our ongoing research on the preparation and the reactivity of imidazole derivatives (Zama et al., 2013a; Zama et al., 2013b; Chelghoum et al., 2011; Bahnous et al., 2012), we describe herein the single-crystal X-ray structure of the enamine 5,5-dimethyl-3-(phenylamino)cyclohex-2-enone (I). This latter has been recovered from our attempt to coupling the dihydropyridine entity with imidazole unit using a "One Pot reaction" strategy implicating aniline, 5,5-dimethyl-1,3-cyclohexandione and N-methylimidazolmethylenemalononitrile. The molecular geometry and the atom-numbering scheme of (I) are shown in Fig. 1. The asymmetric unit of (I) consists of the 5,5-dimethyl-cyclohex-2-enone moiety and its attached phenylamino group. The crystal packing can be described as alternating layers parallel to the (-101)(Fig. 2). It is stabilized by N—H···O hydrogen bond (Fig.3) and C—H···π interactions (Table. 1). These interaction bonds link the molecules within the layers and also link the layers together, reinforcing the cohesion of the structure.

2. Experimental

5,5-dimethyl-3-(phenylamino)cyclohex-2-enone (I) has been obtained from the reaction of aniline and 5,5-dimethyl-1,3-cyclohexandione. In a typical reaction, 1 mmol of 5,5-dimethylcyclohex-1,3-dione, and 1 mmol aniline, in ethanol were placed in a 10 ml round-bottomed flask fitted with a condenser and a magnetic stirrer bar. The reaction mixture was stirred at reflux for 24 h, then 1 mmol of N-methylimidazolmethylenemalononitrile was added to this solution and the reaction mixture was heated for an additional 24 h. The solvent was distilled off and flash chromatographic purification furnished the 5,5-dimethyl-3-(phenylamino)cyclohex-2-enone I and the recovered N-methylimidazolmethylenemalononitrile. Suitable crystals for X-ray experiments of I were obtained by slow evaporation from an ethanol/CH2Cl2 solution at room temperature.