Ethyl 2-[(2,6-dimethyl­phen­yl)hydrazono]-3-oxobutanoate

Hoong-Kun Fun; Samuel Robinson Jebas; Mahesh Padaki; Chitrakar Hegde; Arun M Isloor

doi:10.1107/S160053680902131X

. 2009 Jun 10;65(Pt 7):o1541–o1542. doi: 10.1107/S160053680902131X

Ethyl 2-[(2,6-dimethylphenyl)hydrazono]-3-oxobutanoate

Hoong-Kun Fun ^a,^*,^‡, Samuel Robinson Jebas ^a,^§, Mahesh Padaki ^b, Chitrakar Hegde ^c, Arun M Isloor ^b

PMCID: PMC2969439 PMID: 21582829

Abstract

The title compound, C₁₄H₁₈N₂O₃, crystallizes with two independent molecules in the asymmetric unit, having closely comparable geometries. Both molecules are essentially planar [maximum deviations from the mean plane of 0.069 (1) and 0.068 (1) Å for the two molecules] and contain an intramolecular N—H⋯O hydrogen bond which generates a ring with graph-set motif S(6). In the crystal, the molecules are linked into chains along the c axis by intermolecular C—H⋯O hydrogen bonds, and intermolecular C—H⋯π interactions are also present.

Related literature

For details of the isolation and cytotoxic properties of oxobutanoate derivatives, see: Billington et al. (1979 ▶); Stanchev et al. (2008 ▶). For related structures, see: Alpaslan et al. (2005 ▶); Fun et al. (2009 ▶). For details of the synthesis, see: Amir & Agarwal, (1997 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₄H₁₈N₂O₃
M _r = 262.30
Monoclinic,
a = 6.8072 (1) Å
b = 17.4339 (2) Å
c = 22.9238 (3) Å
β = 90.921 (1)°
V = 2720.15 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.43 × 0.22 × 0.10 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.962, T _max = 0.991
38064 measured reflections
6206 independent reflections
4862 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.110
S = 1.03
6206 reflections
359 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT 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/S160053680902131X/bi2373sup1.cif

e-65-o1541-sup1.cif^{(26.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680902131X/bi2373Isup2.hkl

e-65-o1541-Isup2.hkl^{(297.7KB, 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
C2B—H2BA⋯O2Bⁱ	0.93	2.54	3.2442 (16)	133
N1A—H1NA⋯O1A	0.904 (18)	1.790 (18)	2.5366 (14)	138.3 (15)
N1B—H1NB⋯O1B	0.91 (2)	1.81 (2)	2.5512 (15)	136.2 (16)
C11B—H11C⋯Cg1ⁱⁱ	0.96	2.68	3.5516 (15)	150
C11B—H11D⋯Cg1ⁱⁱⁱ	0.96	2.60	3.4832 (15)	152
C11A—H11A⋯Cg2^iv	0.96	2.61	3.4633 (15)	147
C11A—H11B⋯Cg2^v	0.96	2.65	3.5304 (15)	151

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) . Cg1 and Cg2 are the centroids of the C1A–C6A and C1B–C6B rings, respectively.

Acknowledgments

HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post-doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. AMI is grateful to the Head of the Department of Chemistry and the Director, NITK, Surathkal, India, for providing research facilities.

supplementary crystallographic information

Comment

Derivatives of oxobutanoates are biologically important due to their interesting properties. 4-Methylthio-2-oxobutanoate was identified in the culture fluids of a range of bacteria, the yeast Saccharomyces cerevisiae and the fungus Penicillium digitatum (Billington et al., 1979). Some of the oxobutanoate exhibited cytotoxic property (Stanchev et al., 2008). Crystal structures of ethyl 4-chloro-2-[2-(2-methoxyphenyl)hydrazono]-3-oxobutanoate (Alpaslan et al., 2005) and ethyl 2-[(4-chlorophenyl)hydrazono]-3-oxobutanoate (Fun et al., 2009) have been reported.

There are two independent molecules (A and B) in the asymmetric unit of the title compound (Fig. 1). The benzene rings in the two molecules (C1A–C6A and C1B—C6B) are almost coplanar, forming a dihedral angle of 3.14 (6)°. The mean plane of the part of the oxobutanoate unit, C7A—C12A/O3A in molecule A and C7B—C12B/O3B in molecule B, is slightly twisted from the mean planes of the phenyl rings, (C1A—C6A) and (C1B—C6B), forming dihedral angles of 2.26 (7)° in molecule A and 2.16 (8)° in molecule B respectively. An intramolecular N—H···O hydrogen bond is present in both molecules, generating a ring with graph-set motif S(6).

In the crystal packing (Fig. 2), the molecules are linked into chains along the c axis by intermolecular C—H···O hydrogen bonds. Intramolecular O···N short contacts (2.5362 (13)Å and 2.8224 (14)Å) and intermolecular C—H···π interactions (Table 1) are also observed.

Experimental

The title compound was prepared according to a literature procedure (Amir & Agarwal, 1997): 2,6-dimethylaniline (2.26 g, 0.01 mol) was dissolved in dilute hydrochloric acid (22.0 ml, 9.0 ml HCl dissolved in 13.0 ml water) and cooled to 0°C in an ice bath. To this, a cold solution of sodium nitrite (3.2 g, 0.0462 mol in 10.0 ml water) was added, with the temperature of the reaction mixture kept below 5°C. The resulting diazonium salt solution was filtered into a cooled solution of ethylacetoacetate (3.4 ml) and sodium acetate (7.0 g) in ethanol (100 ml). The resulting yellow-orange solid was filtered, washed with ice cold water, dried in air and recrystallized from methanol. Yield 3.65 g (86.5%), m.p. 338–340 K.