4-[(E)-(2,4,5-Trimeth­oxy­benzyl­idene)amino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

Hoong-Kun Fun; Madhukar Hemamalini; Abdullah M Asiri; Salman A Khan

doi:10.1107/S1600536810021586

. 2010 Jun 16;66(Pt 7):o1656–o1657. doi: 10.1107/S1600536810021586

4-[(E)-(2,4,5-Trimethoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

Hoong-Kun Fun ^a,^*,^‡, Madhukar Hemamalini ^a, Abdullah M Asiri ^b,^§, Salman A Khan ^b

PMCID: PMC3006971 PMID: 21587884

Abstract

The title compound, C₂₁H₂₃N₃O₄, adopts an E configuration about the central C=N double bond and the pyrazolone ring is almost planar, with a maximum deviation of 0.042 (1) Å. The central pyrazolone ring makes dihedral angles of 51.96 (5) and 3.82 (5)° with the attached phenyl and the trimethoxy-substituted benzene rings, respectively. The dihedral angle between the phenyl ring and the trimethoxy-substituted benzene ring is 50.19 (5)° and an intramolecular C—H⋯O hydrogen bond generates an S(6) ring motif. The crystal structure is stabilized by intermolecular C—H⋯O and C—H⋯N hydrogen bonds.

Related literature

For background to the applications of Schiff bases, see: Vukovic et al. (2010 ▶); Ramesh & Maheswaran (2003 ▶); Dongfang et al. (2008 ▶); Sastry & Rao (1988 ▶); Kamel et al. (2010 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₁H₂₃N₃O₄
M _r = 381.42
Monoclinic,
a = 21.0128 (10) Å
b = 7.4242 (4) Å
c = 12.5194 (6) Å
β = 98.675 (1)°
V = 1930.72 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.67 × 0.27 × 0.15 mm

Data collection

Bruker APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.941, T _max = 0.987
23600 measured reflections
5614 independent reflections
4779 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.123
S = 1.04
5614 reflections
345 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); 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/S1600536810021586/hb5480sup1.cif

e-66-o1656-sup1.cif^{(22.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810021586/hb5480Isup2.hkl

e-66-o1656-Isup2.hkl^{(269.3KB, 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
C10—H10A⋯O1	0.954 (13)	2.331 (13)	3.0112 (11)	127.8 (10)
C4—H4A⋯O1ⁱ	0.969 (13)	2.541 (13)	3.2628 (12)	131.4 (10)
C20—H20A⋯N3ⁱⁱ	0.996 (14)	2.577 (14)	3.5383 (13)	162.1 (12)
C20—H20C⋯O2ⁱⁱⁱ	0.977 (14)	2.509 (14)	3.4470 (13)	160.8 (12)
C20—H20C⋯O3ⁱⁱⁱ	0.977 (14)	2.495 (15)	3.2779 (13)	137.0 (11)

Open in a new tab

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

Acknowledgments

HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship. AMA and SAK thank the Chemistry Department, King Abdul Aziz University, Jeddah, Saudi Arabia, for providing research facilities.

supplementary crystallographic information

Comment

Compounds with the structure of AC═NB are known as Schiff base, which can be synthesized from the condensation of amino and active carbonyl groups. Schiff base compounds have shown different therapeutic properties such as antibacterial (Vukovic et al., 2010), antifungal (Ramesh & Maheswaran, 2003), antitumor (Dongfang et al., 2008), anti-inflammatory (Sastry & Rao, 1988) and anticancer activities (Kamel et al., 2010). Due to their importance, the crystal structure determination of the title compound was carried out and the results are presented here.

In the title compound (Fig. 1), the pyrazolone ring (N1/N2/C7–C9) is almost planar, with maximum deviation of 0.042 (1) Å for atom N2. The central pyrazolone (N1/N2/C7–C9) ring makes dihedral angles of 51.96 (5)° and 3.82 (5)° with the attached phenyl ring (C1–C6) and the trimethoxy substituted phenyl ring (C11–C16), respectively. The dihedral angle between the phenyl ring(C1–C6) and the trimethoxy substituted phenyl ring (C11–C16) is 50.19 (5)°. The three methoxy groups are coplanar with the benzene ring [torsion angles C19-O2-C13-C12 = 5.04 (16)°, C20-O3-C14-C15 = -0.36 (14)° and C21-O4-C16-C15 = -1.66 (13)°].

In the crystal packing (Fig. 2), the intramolecular C10—H10A···O1 hydrogen bonding generates an S(6) ring motif (Bernstein et al., 1995). The crystal sturcture is futher stabilized by weak intermolecular C4—H4A···O1, C20—H20C···O2, C20—H20C···O3 and C20—H20A···N3 (Table 1) hydrogen bonds.

Experimental

A mixture of 4-aminophenazone (0.50 g, 0.0033 mol) and 2,4,5-tri-methoxy- benzaldehyde (0.65 g, 0.0033 mol) in methanol (15 ml) was refluxed for 5 h with stirring to give a light yellow precipitate. It was then filtered and washed with methanol to give the pure Schiff base and yellow blocks of (I) were recrystallized from methanol. Yield: 48.18%; Mp. 381°C; IR (KBr) ν_max cm^-1: 2937 (C–H), 1644 (C═C), 1609(C═O), 1591 (C═N), 1122 (N–N). ¹H-NMR (CDCl₃) d: 10.02 ((s, 1H, CH olefinic), 7.67 (s, H3, CHaromatic), 6.49 (s, H6, CHaromatic), 7.47–7.26 (m, 5H, CHaromatic), 3.93 (s, OCH₃), 3.93 (s, OCH₃), 3.84 (s, OCH₃), 3.11(s, N-CH₃), 2.48 (s,-CH₃).