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

The crystal structure of the title compound, C₁₉H₁₉N₃O₂, shows the mol­ecule to be essentially planar with the exception of the terminal phenyl group. Mol­ecules are associated via inter­molecular C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C)= 0.002 Å
• R factor = 0.042
• wR factor = 0.120
• Data-to-parameter ratio = 18.0

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S1. Comment

Metal complexes of Schiff bases have attracted much attention because they can be utilized as model compounds for the active centres in various enzymes and proteins (Kahwa et al., 1986; Santos et al., 2001). Important to the understanding of the coordination potential of these ligands is a knowledge of the ligand structure. Accordingly, the synthesis and crystal structures of Schiff base ligands derived from 4-aminoantipyrine, such as thenoyltrifluoroacetone (Yu et al., 2002), 4-hydroxy-3-methoxybenzaldehyde (Diao et al., 2005) and 2,4-dichlorobenzaldehyde (Jing et al., 2005), have been reported.

In the molecular structure of the related title compound, (I) (Fig. 1), the expected geometric parameters are observed (Table 1). The central chromophore containing the C9–C11/N1–N3/O2 atoms is planar, with an r.m.s. deviation for fitted atoms of 0.038 (2) Å; the 4-methoxybenzaldehyde moiety (C1–C8/O1) is also planar, with an r.m.s. deviation of 0.027 (5) Å. The dihedral angles formed between these planes and that through the C14–C19 phenyl ring are 48.24 (5) and 9.40 (6)°, respectively. Intramolecular C—H···O hydrogen bonding stabilizes the molecular conformation, while intermolecular C—H···O hydrogen bonding stabilizes the crystal structure; geometric details are given in Table 2. The molecules associate in a zigzag pattern along the c axis, forming a supramolecular structure, as illustrated in Fig. 2.

S2. Experimental

An anhydrous ethanol solution of 4-methoxy-benzaldehyde (1.36 g, 10 mmol) was added to an anhydrous ethanol solution of 4-amino-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one (2.03 g, 10 mmol) and the mixture was stirred at 350 K for 8 h under N₂, whereupon a yellow solution appeared. The solvent was removed and the residue recrystallized from N,N-dimethylformamide. The product was isolated and then dried in vacuo to give pure (I) in 79% yield. Yellow single crystals suitable for X-ray analysis were obtained by slow evaporation of an N,N-dimethylformamide solution of (I).

S3. Refinement

The H atoms were included in calculated positions and refined using a riding model, with aromatic C—H = 0.93 Å, methyl C—H = 0.96 Å and N—H = 0.96 Å, and with U_iso(H) = 1.2U_eq(C,N) for aromatic and N-bound H atoms, and U_iso(H) = 1.5U_eq(C) for methyl H atoms.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of (I), with displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. Intermolecular hydrogen-bonding interactions (dashed lines) in (I).

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

Crystal data

C19H19N3O2	F(000) = 680
Mr = 321.37	Dx = 1.278 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2518 reflections
a = 7.1407 (10) Å	θ = 2.3–23.6°
b = 24.864 (3) Å	µ = 0.09 mm^−1
c = 9.4733 (13) Å	T = 294 K
β = 96.700 (2)°	Block, yellow
V = 1670.4 (4) Å^3	0.20 × 0.16 × 0.14 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	3949 independent reflections
Radiation source: fine-focus sealed tube	2677 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ϕ and ω scans	θmax = 27.8°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→8
Tmin = 0.980, Tmax = 0.988	k = −31→32
11145 measured reflections	l = −12→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.120	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0574P)^2 + 0.1906P] where P = (Fo^2 + 2Fc^2)/3
3949 reflections	(Δ/σ)max = 0.001
220 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.22790 (17)	0.70587 (4)	1.19517 (13)	0.0624 (3)
O2	0.19837 (14)	0.41882 (4)	0.71804 (11)	0.0522 (3)
N1	0.46932 (16)	0.51705 (5)	0.79389 (12)	0.0413 (3)
N2	0.60395 (15)	0.41890 (5)	0.55082 (12)	0.0405 (3)
N3	0.43987 (15)	0.39400 (5)	0.58744 (12)	0.0407 (3)
C1	0.3709 (3)	0.74566 (7)	1.2206 (2)	0.0750 (6)
H1A	0.4799	0.7302	1.2745	0.113*
H1B	0.3250	0.7749	1.2729	0.113*
H1C	0.4043	0.7587	1.1315	0.113*
C2	0.4532 (2)	0.60747 (6)	0.98053 (15)	0.0452 (4)
H2	0.5685	0.6008	0.9473	0.054*
C3	0.4333 (2)	0.65276 (6)	1.06163 (16)	0.0470 (4)
H3	0.5336	0.6765	1.0816	0.056*
C4	0.2629 (2)	0.66257 (6)	1.11298 (16)	0.0462 (4)
C5	0.1153 (2)	0.62678 (7)	1.08438 (18)	0.0548 (4)
H5	0.0014	0.6329	1.1203	0.066*
C6	0.1372 (2)	0.58201 (7)	1.00253 (18)	0.0533 (4)
H6	0.0371	0.5582	0.9837	0.064*
C7	0.3060 (2)	0.57159 (6)	0.94728 (15)	0.0422 (3)
C8	0.3254 (2)	0.52403 (6)	0.85985 (15)	0.0446 (3)
H8	0.2306	0.4982	0.8521	0.054*
C9	0.48477 (19)	0.47171 (6)	0.70981 (14)	0.0379 (3)
C10	0.63373 (19)	0.46336 (6)	0.63383 (14)	0.0382 (3)
C11	0.35503 (19)	0.42789 (6)	0.68046 (14)	0.0388 (3)
C12	0.8094 (2)	0.49533 (6)	0.63592 (18)	0.0508 (4)
H12A	0.9158	0.4732	0.6689	0.076*
H12B	0.8041	0.5255	0.6985	0.076*
H12C	0.8220	0.5079	0.5417	0.076*
C13	0.7551 (2)	0.38417 (6)	0.51215 (18)	0.0537 (4)
H13A	0.8598	0.4059	0.4917	0.081*
H13B	0.7100	0.3634	0.4297	0.081*
H13C	0.7949	0.3604	0.5897	0.081*
C14	0.33546 (19)	0.35873 (5)	0.49036 (14)	0.0382 (3)
C15	0.2232 (2)	0.32000 (6)	0.54370 (16)	0.0473 (4)
H15	0.2200	0.3169	0.6412	0.057*
C16	0.1164 (2)	0.28610 (6)	0.45170 (18)	0.0538 (4)
H16	0.0399	0.2603	0.4873	0.065*
C17	0.1220 (2)	0.29009 (7)	0.30723 (18)	0.0565 (4)
H17	0.0509	0.2669	0.2455	0.068*
C18	0.2334 (2)	0.32864 (7)	0.25501 (17)	0.0561 (4)
H18	0.2368	0.3314	0.1574	0.067*
C19	0.3404 (2)	0.36338 (6)	0.34535 (15)	0.0465 (4)
H19	0.4148	0.3895	0.3091	0.056*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0631 (7)	0.0472 (7)	0.0782 (8)	0.0067 (5)	0.0140 (6)	−0.0143 (6)
O2	0.0382 (6)	0.0619 (7)	0.0592 (7)	−0.0067 (5)	0.0170 (5)	−0.0081 (5)
N1	0.0409 (7)	0.0434 (7)	0.0395 (6)	0.0026 (5)	0.0051 (5)	−0.0002 (5)
N2	0.0319 (6)	0.0450 (7)	0.0458 (7)	−0.0004 (5)	0.0097 (5)	−0.0020 (5)
N3	0.0336 (6)	0.0469 (7)	0.0425 (6)	−0.0042 (5)	0.0086 (5)	−0.0035 (5)
C1	0.0735 (13)	0.0529 (11)	0.0961 (15)	0.0042 (9)	−0.0010 (11)	−0.0191 (10)
C2	0.0419 (8)	0.0520 (9)	0.0432 (8)	0.0015 (7)	0.0119 (6)	0.0015 (7)
C3	0.0465 (9)	0.0465 (9)	0.0483 (9)	−0.0032 (7)	0.0066 (7)	0.0008 (7)
C4	0.0505 (9)	0.0409 (8)	0.0474 (8)	0.0085 (7)	0.0065 (7)	0.0015 (6)
C5	0.0441 (9)	0.0565 (10)	0.0666 (10)	0.0058 (7)	0.0182 (8)	−0.0069 (8)
C6	0.0425 (9)	0.0542 (10)	0.0651 (10)	−0.0042 (7)	0.0141 (7)	−0.0072 (8)
C7	0.0434 (8)	0.0443 (8)	0.0397 (8)	0.0027 (6)	0.0075 (6)	0.0012 (6)
C8	0.0421 (8)	0.0481 (9)	0.0442 (8)	−0.0015 (6)	0.0070 (6)	−0.0016 (6)
C9	0.0353 (7)	0.0421 (8)	0.0363 (7)	0.0017 (6)	0.0041 (6)	0.0023 (6)
C10	0.0336 (7)	0.0407 (8)	0.0401 (7)	0.0026 (6)	0.0030 (6)	0.0045 (6)
C11	0.0340 (7)	0.0462 (8)	0.0363 (7)	0.0023 (6)	0.0041 (6)	0.0016 (6)
C12	0.0381 (8)	0.0513 (9)	0.0641 (10)	−0.0032 (7)	0.0105 (7)	−0.0001 (8)
C13	0.0425 (9)	0.0565 (10)	0.0645 (10)	0.0050 (7)	0.0163 (8)	−0.0078 (8)
C14	0.0342 (7)	0.0384 (7)	0.0420 (8)	0.0020 (6)	0.0042 (6)	−0.0006 (6)
C15	0.0485 (9)	0.0499 (9)	0.0440 (8)	−0.0040 (7)	0.0075 (7)	0.0033 (7)
C16	0.0511 (9)	0.0516 (9)	0.0600 (10)	−0.0129 (7)	0.0111 (8)	0.0002 (8)
C17	0.0555 (10)	0.0583 (10)	0.0559 (10)	−0.0137 (8)	0.0073 (8)	−0.0129 (8)
C18	0.0632 (11)	0.0627 (11)	0.0429 (9)	−0.0105 (8)	0.0086 (8)	−0.0057 (7)
C19	0.0500 (9)	0.0456 (9)	0.0447 (8)	−0.0059 (7)	0.0091 (7)	0.0002 (7)

Geometric parameters (Å, º)

O1—C1	1.422 (2)	C7—C8	1.460 (2)
O1—C4	1.3684 (18)	C8—H8	0.9300
O2—C11	1.2336 (16)	C9—C10	1.3679 (18)
N1—C8	1.2754 (18)	C9—C11	1.436 (2)
N1—C9	1.3920 (17)	C10—C12	1.483 (2)
N2—N3	1.4040 (15)	C12—H12A	0.9600
N2—C10	1.3589 (18)	C12—H12B	0.9600
N2—C13	1.4620 (17)	C12—H12C	0.9600
N3—C11	1.4065 (17)	C13—H13A	0.9600
N3—C14	1.4181 (17)	C13—H13B	0.9600
C1—H1A	0.9600	C13—H13C	0.9600
C1—H1B	0.9600	C14—C19	1.383 (2)
C1—H1C	0.9600	C14—C15	1.3854 (19)
C2—C3	1.380 (2)	C15—C16	1.377 (2)
C2—C7	1.387 (2)	C15—H15	0.9300
C2—H2	0.9300	C16—C17	1.377 (2)
C3—C4	1.384 (2)	C16—H16	0.9300
C3—H3	0.9300	C17—C18	1.374 (2)
C4—C5	1.382 (2)	C17—H17	0.9300
C5—C6	1.376 (2)	C18—C19	1.382 (2)
C5—H5	0.9300	C18—H18	0.9300
C6—C7	1.393 (2)	C19—H19	0.9300
C6—H6	0.9300
C1—O1—C4	117.94 (13)	N1—C9—C11	129.25 (12)
C8—N1—C9	120.85 (13)	N2—C10—C9	110.44 (12)
N3—N2—C10	107.12 (10)	N2—C10—C12	121.24 (12)
N3—N2—C13	117.60 (11)	C9—C10—C12	128.32 (13)
C10—N2—C13	123.72 (12)	O2—C11—N3	122.87 (13)
N2—N3—C11	108.88 (11)	O2—C11—C9	131.99 (13)
N2—N3—C14	120.21 (11)	N3—C11—C9	105.10 (11)
C11—N3—C14	122.99 (11)	C10—C12—H12A	109.5
O1—C1—H1A	109.5	C10—C12—H12B	109.5
O1—C1—H1B	109.5	H12A—C12—H12B	109.5
H1A—C1—H1B	109.5	C10—C12—H12C	109.5
O1—C1—H1C	109.5	H12A—C12—H12C	109.5
H1A—C1—H1C	109.5	H12B—C12—H12C	109.5
H1B—C1—H1C	109.5	N2—C13—H13A	109.5
C3—C2—C7	121.80 (14)	N2—C13—H13B	109.5
C3—C2—H2	119.1	H13A—C13—H13B	109.5
C7—C2—H2	119.1	N2—C13—H13C	109.5
C2—C3—C4	119.44 (14)	H13A—C13—H13C	109.5
C2—C3—H3	120.3	H13B—C13—H13C	109.5
C4—C3—H3	120.3	C19—C14—C15	120.21 (13)
O1—C4—C5	115.63 (13)	C19—C14—N3	121.33 (12)
O1—C4—C3	124.40 (14)	C15—C14—N3	118.43 (12)
C5—C4—C3	119.96 (14)	C16—C15—C14	119.73 (14)
C6—C5—C4	119.82 (14)	C16—C15—H15	120.1
C6—C5—H5	120.1	C14—C15—H15	120.1
C4—C5—H5	120.1	C15—C16—C17	120.42 (15)
C5—C6—C7	121.49 (15)	C15—C16—H16	119.8
C5—C6—H6	119.3	C17—C16—H16	119.8
C7—C6—H6	119.3	C18—C17—C16	119.55 (15)
C2—C7—C6	117.47 (14)	C18—C17—H17	120.2
C2—C7—C8	122.03 (13)	C16—C17—H17	120.2
C6—C7—C8	120.49 (14)	C17—C18—C19	120.96 (15)
N1—C8—C7	121.58 (14)	C17—C18—H18	119.5
N1—C8—H8	119.2	C19—C18—H18	119.5
C7—C8—H8	119.2	C18—C19—C14	119.11 (14)
C10—C9—N1	122.85 (13)	C18—C19—H19	120.4
C10—C9—C11	107.85 (12)	C14—C19—H19	120.4
C10—N2—N3—C11	8.01 (14)	N1—C9—C10—N2	−174.02 (12)
C13—N2—N3—C11	152.76 (13)	C11—C9—C10—N2	3.67 (15)
C10—N2—N3—C14	157.91 (12)	N1—C9—C10—C12	6.8 (2)
C13—N2—N3—C14	−57.34 (17)	C11—C9—C10—C12	−175.47 (14)
C7—C2—C3—C4	0.8 (2)	N2—N3—C11—O2	172.13 (13)
C1—O1—C4—C5	−176.20 (15)	C14—N3—C11—O2	23.2 (2)
C1—O1—C4—C3	5.1 (2)	N2—N3—C11—C9	−5.70 (14)
C2—C3—C4—O1	179.46 (14)	C14—N3—C11—C9	−154.58 (12)
C2—C3—C4—C5	0.8 (2)	C10—C9—C11—O2	−176.20 (15)
O1—C4—C5—C6	179.99 (15)	N1—C9—C11—O2	1.3 (3)
C3—C4—C5—C6	−1.3 (2)	C10—C9—C11—N3	1.35 (15)
C4—C5—C6—C7	0.1 (3)	N1—C9—C11—N3	178.84 (13)
C3—C2—C7—C6	−1.9 (2)	N2—N3—C14—C19	−26.13 (19)
C3—C2—C7—C8	179.11 (14)	C11—N3—C14—C19	119.41 (15)
C5—C6—C7—C2	1.4 (2)	N2—N3—C14—C15	155.59 (13)
C5—C6—C7—C8	−179.55 (15)	C11—N3—C14—C15	−58.87 (18)
C9—N1—C8—C7	−179.36 (12)	C19—C14—C15—C16	0.0 (2)
C2—C7—C8—N1	−9.8 (2)	N3—C14—C15—C16	178.30 (14)
C6—C7—C8—N1	171.25 (14)	C14—C15—C16—C17	0.7 (2)
C8—N1—C9—C10	177.98 (13)	C15—C16—C17—C18	−0.8 (3)
C8—N1—C9—C11	0.8 (2)	C16—C17—C18—C19	0.2 (3)
N3—N2—C10—C9	−7.20 (15)	C17—C18—C19—C14	0.5 (2)
C13—N2—C10—C9	−149.25 (13)	C15—C14—C19—C18	−0.6 (2)
N3—N2—C10—C12	172.00 (13)	N3—C14—C19—C18	−178.82 (13)
C13—N2—C10—C12	30.0 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···O2	0.93	2.34	3.0310 (18)	131
C5—H5···O2^i	0.93	2.56	3.2838 (19)	135
C12—H12A···O2^ii	0.96	2.43	3.3815 (19)	172

Symmetry codes: (i) −x, −y+1, −z+2; (ii) x+1, y, z.