(Z)-4-(2-Naphthyl­amino)­pent-3-en-2-one

Mohamed Anoir Harrad; Brahim Boualy; Abdelghani Oudahmane; Daniel Avignant; Corrado Rizzoli

doi:10.1107/S1600536811024494

. 2011 Jun 25;67(Pt 7):o1818. doi: 10.1107/S1600536811024494

(Z)-4-(2-Naphthylamino)pent-3-en-2-one

Mohamed Anoir Harrad ^a, Brahim Boualy ^a, Abdelghani Oudahmane ^b, Daniel Avignant ^b, Corrado Rizzoli ^c,^*

PMCID: PMC3151978 PMID: 21837187

Abstract

The title compound, C₁₅H₁₅NO, which was synthesized under solvent-free conditions by the reaction of acetoacetone and 2-naphthylamine, adopts a Z conformation about the C=C bond. The enamine–ketone fragment is approximately planar [maximum deviation = 0.026 (3) Å] and forms a dihedral angle of 39.78 (3)° with the naphthalene ring system. An intramolecular N—H⋯O hydrogen bond is observed.

Related literature

For our studies on the synthesis of β-enaminones and β-enamino esters, see: Harrad et al. (2010 ▶, 2011 ▶). For related structures, see: Shaheen et al. (2006 ▶); Arıcı et al. (1999 ▶).

Experimental

Crystal data

C₁₅H₁₅NO
M _r = 225.28
Orthorhombic,
a = 11.2417 (18) Å
b = 8.2532 (10) Å
c = 26.570 (4) Å
V = 2465.2 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.48 × 0.34 × 0.12 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS, Bruker, 2008 ▶) T _min = 0.660, T _max = 0.746
9535 measured reflections
2221 independent reflections
1179 reflections with I > 2σ(I)
R _int = 0.057

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.142
S = 0.94
2221 reflections
159 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and SCHAKAL97 (Keller, 1997 ▶); software used to prepare material for publication: SHELXL97 and PARST95 (Nardelli, 1995 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811024494/ng5187sup1.cif

e-67-o1818-sup1.cif^{(15.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811024494/ng5187Isup2.hkl

e-67-o1818-Isup2.hkl^{(109.3KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811024494/ng5187Isup3.cml

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—H1N⋯O1	0.92 (2)	1.85 (2)	2.657 (2)	144 (2)

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Acknowledgments

Financial support from the Universitá degli Studi di Parma is gratefully acknowledged.

supplementary crystallographic information

Comment

β-Enaminones and β-enaminoesters are useful precursors for the preparation of biologically active compounds such as β-enamino acids and γ-enamino alcohols, and many synthetic methods have been developed for the preparation of these compounds. As a continuation of our work on the synthesis and characterization of new β-enamino compounds (Harrad et al., 2010, 2011), we describe herein the crystal structure of title compound.

The title compound (Fig. 1) crystallizes in the keto-enamine form, as indicated by values of the C14═O1 and C13–C14 bond length of 1.252 (3) and 1.410 (3) Å, respectively. The bond lengths observed within the C13–C12–N1 chain (C12–C13 = 1.375 (3) Å; N1–C12 = 1.353 (3) Å) suggest some degree of electron delocalization of the imino and alkene double bonds. The molecule assumes a Z conformation about the C12═C13 bond. An S(6) ring motif is formed due to an intramolecular N—H···O hydrogen bond (Table 1). The enamino-ketone fragment (N1/C12/c13/C14/O1) is approximately planar (maximum deviation 0.026 (3) Å for atom C14) and is twisted by 39.78 (3)° with respect to the naphthalene ring. This value is comparable with those of 32.06 (9) and 44.71 (7)° found in (Z)-4-anilinopent-3-en-2-one (Shaheen et al., 2006) and 4-chloro-2-(4-oxopent-2-en-2-ylamino)phenol (Arıcı et al., 1999), respectively. The crystal packing (Fig. 2) is governed only by van der Waals interactions. No C—H···π or π···π interactions are observed.

Experimental

A mixture of acetoacetone (5 mmol), 2-naphthylamine (5 mmol) and Ca(CF₃CO₂)₂ (0.05 mmol) was stirred at room temperature for 1 h under solvent-free conditions. After completion of the reaction, the mixture was diluted with H₂O (10 ml), extracted with EtOAc (2 × 10 ml) and dried over Na₂SO₄. The title compound was isolated as a white powder by column chromatography on silica gel using ethyl acetate/n-hexane (1:1 v/v) as eluent (yield 62%; m. p.= 395 K). Colourless single crystals suitable for X-ray analysis were obtained by slow evaporation at room temperature of an n-hexane solution. ¹H NMR (CDCl₃, 300 MHz) δ: 1.9 (s; 3H), 2.2 (s, 3H), 3.1 (s, 1H); 7.2–7.7 (m, 7H, Ar), 12.6 (bs, 1H, HN); ¹³C NMR (CDCl₃, 75 MHz) δ: 19.96, 30.53, 97.04, 127.95, 130.10, 132.50, 135.14, 126.61, 125.23; 124.63, 122.81; 120.58; 159.25, 195.23. EIMS (m/z) 226.1 (M⁺). HRMS calcd for C₁₅H₁₅NO: 225.1154; found 225.1163.