4-But­oxy-N′-[1-(4-methyl­phen­yl)ethyl­idene]benzohydrazide

Nefise Dilek; Bilal Gunes; Ramazan Gup

doi:10.1107/S1600536812035921

. 2012 Aug 25;68(Pt 9):o2763. doi: 10.1107/S1600536812035921

4-Butoxy-N′-[1-(4-methylphenyl)ethylidene]benzohydrazide

Nefise Dilek ^a,^*, Bilal Gunes ^b, Ramazan Gup ^c

PMCID: PMC3435798 PMID: 22969644

Abstract

The molecule of the title compound, C₂₀H₂₄N₂O₂, exists in a trans conformation with respect to the C=N bond. The dihedral angle between the benzene rings is 79.0 (1)°. In the crystal, N—H⋯O hydrogen bonds link the molecules into chains propagating in [001]. Two weak C—H⋯O interactions also occur.

Related literature

For acylhydrazone compounds, see: Rollas & Küçükgüzel (2007 ▶); Vicini et al. (2006 ▶); Chimenti et al. (2007 ▶). For aroylhydrazone compounds, see: Barbazan et al., 2008 ▶; Dang et al., 2007 ▶. Hydrazones typically act as bi- and tridentate, mono or biprotic depending on the reaction conditions, see: Gup & Kirkan (2005 ▶); Naskar et al. (2004 ▶); Sreeja et al. (2003 ▶). For bond lengths and angles in similar structures, see: Li & Ban (2009 ▶); Mao et al. (2011 ▶); Singh & Singh (2010 ▶).

Experimental

Crystal data

C₂₀H₂₄N₂O₂
M _r = 324.41
Monoclinic,
a = 15.0800 (4) Å
b = 14.0134 (4) Å
c = 8.2419 (2) Å
β = 94.609 (2)°
V = 1736.06 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 105 K
0.38 × 0.21 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.970, T _max = 0.987
8163 measured reflections
2150 independent reflections
1980 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.101
S = 0.93
2150 reflections
220 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536812035921/bq2373sup1.cif

e-68-o2763-sup1.cif^{(26.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812035921/bq2373Isup2.hkl

e-68-o2763-Isup2.hkl^{(105.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812035921/bq2373Isup3.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—H1⋯O2ⁱ	0.88	2.15	2.975 (2)	155
C16—H16C⋯O2ⁱ	0.98	2.57	3.307 (3)	131
C17—H17⋯O2ⁱⁱ	0.95	2.59	3.527 (3)	168

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

Acknowledgments

The authors are indebted to Anadolu University and the Medicinal Plants and Medicine Research Centre of Anadolu University, Eskisehir, Turkey, for the use of the X-ray diffractometer.

supplementary crystallographic information

Comment

Acylhydrazones and their derivatives constitute a versatile class of compounds in organic and coordination chemistry. These compounds have interesting biological properties, such as anti-inflammatory, analgesic, anticonvulsant, antituberculous, antitumor, anti-HIV and antimicrobial activity (Rollas & Küçükgüzel, 2007; Vicini et al., 2006; Chimenti et al., 2007).

Aroylhydrazones are important compounds for drug design, as possible ligands for metal complexes, catalysis and also for the syntheses of heterocyclic compounds (Barbazan et al., 2008; Dang et al., 2007). The ease of preparation, increased hydrolytic stability relative to imines, and tendency toward crystallinity are all desirable characteristics of hydrazones. Due to these positive traits, the chemical properties of aroylhydrazones have been extensively studied for a long time. Acylhydrazones possess two connected nitrogen atoms of different nature and a carbon-nitrogen double bond that is conjugated with a lone electron pair of the terminal nitrogen atom. These structural fragments are mainly responsible for the physical and chemical properties of hydrazones. The introduction of functional groups in the hydrazone molecules expands the scope of use in coordination chemistry.

Aroylhydrazones are potential ligands due to having a number of bonding sites. They can act a neutral or monoanionic bidentate or tridentate ligand depending on the substituents and the reaction conditions. Furthermore, abilities to coordinate to metals either in keto (I) or enol (II) tautomeric form make them attractive as ligands. This compound is in the keto form in the solid state. The keto hydrazone moiety may coordinate to metals in the keto amide or deprotonated enolimine form. Hydrazones typically act as bi- and tridentate, mono or biprotic depending on the reaction conditions (Sreeja et al., 2003; Naskar et al., 2004; Gup & Kirkan, 2005).

The crystal structure is shown in Fig. 1 with atom-numbering scheme. The bond lengths and angles are in the normal ranges in the molecule. The molecule exist in a trans configuration with respect to the C10═N2 [1.286 (3) Å] bond and the torsion angle N1—N2—C10—C11 = 176.6 (2)°. The O1—C5, O1—C4 and O2═C9 bond lengths are 1.363 (3) Å, 1.444 (3) Å and 1.229 (3) Å, respectively. The N1—C9 and N1—N2 bond lengths are 1.356 (3) Å and 1.390 (3) Å. The other bond lengths and angles in the molecule are within expected ranges, and similar to the other studies (Singh & Singh, 2010; Li & Ban, 2009; Mao et al., 2011).

The ring A (C5–C8, C19, C20) and B (C11–C14, C17, C18) are each essentially planar. The dihedral angle between two substituted benzene rings is 79.0 (1)°, indicating the Schiff base molecule is twisted. The N1 atom lie above 0.937 (4) Å from the A plane. The N2 atom lie above 0.585 (4) Å from the B plane.

As can be seen from the packing diagram (Fig. 2), inter-molecular N—H···O and C—H···O hydrogen bonds (Table 1) link the molecules and these hydrogen bonds may be effective in the stabilization of the crystal structure. In these interactions, there are the N1, C16 and C17 atoms of molecule as donor and the O2 atom of the other molecules as acceptor (Table 1, Fig. 2).

Experimental

4'-Methylacetophenon (4 mmol, 0.552 g) dissolved in ethanol (10 ml) was added dropwise to a suspension of 4-hydroxybenzohydrazide (4 mmol, 0.608 g) with two drops of glacial acetic acid in ethanol (40 ml) in room temperature. The reaction mixture was refluxed for further 8 h and the colorless product was filtered. The pure hydrazone was collected by crystallization from ethanol.

A mixture 4-hydroxy-N'-[(1E)-1-(4-methylphenyl)ethylidene]benzohydrazide (10 mmol, 2.68 g), 1-bromobutane (10 mmol, 1.370 g) and dry K₂CO₃ (10 mmol, 1.380 g) in 40 ml acetone was refluxed with stirring for 24 h and poured to 200 ml of cold water. The white precipitate formed was filtered and washed with water and finally recrystallized from acetone-water. Chemical structure of title compound is given (I).