N′-[(E)-4-Bromo­benzyl­idene]-2-(4-isobutyl­phen­yl)propanohydrazide

Hoong-Kun Fun; Ching Kheng Quah; K V Sujith; B Kalluraya

doi:10.1107/S1600536809015542

. 2009 May 7;65(Pt 6):o1184–o1185. doi: 10.1107/S1600536809015542

N′-[(E)-4-Bromobenzylidene]-2-(4-isobutylphenyl)propanohydrazide

Hoong-Kun Fun ^a,^*,^‡, Ching Kheng Quah ^a,^§, K V Sujith ^b, B Kalluraya ^b

PMCID: PMC2969560 PMID: 21583058

Abstract

The asymmetric unit of the title compound, C₂₀H₂₃BrN₂O, contains two independent molecules (A and B), in which the orientations of the 4-isobutylphenyl units are different. The dihedral angle between the two benzene rings is 88.45 (8)° in molecule A and 89.87 (8)° in molecule B. Molecules A and B are linked by a C—H⋯N hydrogen bond. In the crystal, molecules are linked into chains running along the a axis by intermolcular N—H⋯O and C—H⋯O hydrogen bonds. The crystal structure is further stabilized by C—H⋯π interactions. The presence of pseudosymmetry in the structure suggests the higher symmetry space group Pbca. However, attempts to refine the structure in this space group resulted in a disorder model with high R (0.097) and wR (0.257) values. The crystal studied was an inversion twin with a 0.595 (4):0.405 (4) domain ratio.

Related literature

For the biological activities of hydrazone derivatives, see: Bedia et al. (2006 ▶); Rollas et al. (2002 ▶); Terzioglu & Gürsoy (2003 ▶); Sridhar & Perumal (2003 ▶); Amir & Kumar (2007 ▶). For a related structure, see: Fun et al. (2008 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₀H₂₃BrN₂O
M _r = 387.31
Orthorhombic,
a = 9.1440 (1) Å
b = 12.0110 (1) Å
c = 33.5670 (4) Å
V = 3686.62 (7) Å³
Z = 8
Mo Kα radiation
μ = 2.24 mm⁻¹
T = 100 K
0.49 × 0.38 × 0.19 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.407, T _max = 0.682
120355 measured reflections
20557 independent reflections
13317 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.103
S = 1.04
20557 reflections
448 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.72 e Å⁻³
Δρ_min = −0.62 e Å⁻³
Absolute structure: Flack (1983 ▶), 9205 Friedel pairs
Flack parameter: 0.595 (4)

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/S1600536809015542/ci2787sup1.cif

e-65-o1184-sup1.cif^{(31.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809015542/ci2787Isup2.hkl

e-65-o1184-Isup2.hkl^{(1,004.5KB, hkl)}

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

Table 1. Selected torsion angles (°).

C8A—C9A—C10A—C11A	−96.54 (17)
C8A—C9A—C10A—C15A	80.18 (18)
C20A—C9A—C10A—C11A	141.61 (15)
C20A—C9A—C10A—C15A	−41.7 (2)
C8B—C9B—C10B—C11B	77.53 (17)
C8B—C9B—C10B—C15B	−101.83 (16)
C20B—C9B—C10B—C11B	−160.06 (14)
C20B—C9B—C10B—C15B	20.6 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2A—H1NA⋯O1Bⁱ	0.91 (2)	1.97 (2)	2.830 (2)	157 (2)
N2B—H1NB⋯O1Aⁱⁱ	0.77 (2)	2.11 (2)	2.826 (2)	155 (2)
C7A—H7AA⋯O1Bⁱ	0.93	2.45	3.241 (2)	143
C7B—H7BA⋯O1Aⁱⁱ	0.93	2.53	3.307 (3)	141
C20B—H20F⋯N1A	0.96	2.56	3.494 (2)	164
C12A—H12A⋯Cg2ⁱ	0.93	2.66	3.482 (2)	148
C12B—H12B⋯Cg1ⁱⁱ	0.93	2.79	3.680 (2)	160

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

Acknowledgments

HKF and CKQ acknowledge funding from the Malaysian Government and Universiti Sains Malaysia (USM) under the Research University Golden Goose Grant (No. 1001/PFIZIK/811012). CKQ thanks Universiti Sains Malaysia for a fellowship.

supplementary crystallographic information

Comment

Hydrazones have been found to possess antimicrobial, anticonvulsant, analgesic, antiinflammatory, antiplatelet, antitubercular, anticancer and antitumoral activities (Bedia et al., 2006; Rollas et al., 2002; Terzioglu & Gürsoy, 2003). Aryl hydrazones are important building blocks for the synthesis of a variety of heterocyclic compounds such as pyrazolines and pyrazoles (Sridhar et al., 2003). Aryl hydrazones have been most conveniently synthesized by the reaction of aryl hydrazines with carbonyl compounds. Similarly ibuprofen is also known for their pharmaceutical activities and belongs to the class of Non-Steroidal Anti-Inflammatory Drugs (Amir & Kumar, 2007). We are interested in the synthesis and crystal structure of ibuprofen containing hydrazone derivatives (Fun et al., 2008). Prompted by these observations, it was contemplated to synthesize and report the crystal structure of the title compound.

The asymmetric unit contains two independent molecules (Fig. 1), A and B, in which the orientations of the 4-isobutylphenyl units are different (Table 1). The bond lengths (Allen et al., 1987) and angles in the molecule (Fig. 1) are within normal ranges and are comparable to a closely related structure (Fun et al., 2008). The molecule A is linked to the molecule B by C20B—H20F···N1A hydrogen bond (Fig. 1). The dihedral angle formed by the C1A-C6A and C10A-C15A benzene rings is 89.87 (8)° and that between the C1B-C6B and C10B-C15B planes is 88.45 (8)°, indicating that they are almost perpendicular to each other.

The crystal packing is consolidated by intermolecular N—H···O and C—H···O hydrogen bonds (Fig. 2) which link the independent molecules into chains parallel to the [100]. The crystal structure is further stabilized by C—H···π interactions (Table 1) involving the C1A-C6A (centroid Cg1) and C1B–C6B (centroid Cg2) benzene rings.

Experimental

The title compound was obtained by refluxing a mixture of 2-[4-(2-methylpropyl)phenyl]propanehydrazide (0.01 mol), 4-bromobenzaldehyde (0.01 mol) in ethanol (30 ml) and 3 drops of concentrated sulfuric acid for 1 h. Excess ethanol was removed from the reaction mixture under reduced pressure. The solid product obtained was filtered, washed with ethanol and dried. Single crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol-N,N-dimethylformamide (DMF) (3:1) solution.