3-(4-Methoxy­phenyl)-4-(5-phenyl-2,4-pentadienoyl)­sydnone

The dihedral angle between the sydnone moiety and methoxy­phenyl ring of the title compound, C₂₀H₁₆N₂O₄, is 66.32 (10)°. Electron conjugation is observed between the pentadienone group and the attached phenyl ring. In the crystal structure, symmetry-related mol­ecules are linked by weak intermolecular C—H...O interactions to form a sheet-like structure, which lies parallel to the ab plane.

Key indicators

• Single-crystal X-ray study
• T = 160 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.044
• wR factor = 0.119
• Data-to-parameter ratio = 7.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_601  Alert C Structure Contains Solvent Accessible VOIDS of      40.00 A   3

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           25.01
         From the CIF: _reflns_number_total               1752
         Count of symmetry unique reflns         1761
         Completeness (_total/calc)             99.49%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured         0
         Fraction of Friedel pairs measured     0.000
         Are heavy atom types Z>Si present           no
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

---

S1. Comment

Sydnones are the product of dehydration of N-nitroso-α-amino acids and are named after the site of their discovery at the University of Sydney (Earl & Mackney, 1935). They have attained importance due, not only to their structural features and chemical properties, but also to their biological properties. Sydnones are less toxic (Pillai et al., 1993), but potent porphyrinogenic (Sutherland et al., 1986; Marks, 1987) and anti-inflammatory (Satyanarayana & Rao, 1995) compounds, and have the effect of scavenging free-radicals (Narla & Rao, 1995). Sydnone halogen derivatives change their colour irreversibly under the influence of UV light (λ < 400 nm) (Hašek et al., 1979). In view of its biological importance, the crystal structure analysis of the title sydnone, (I), was carried out.

The bond lengths in the sydnone ring of (I) agree with the corresponding average values given in Table 1 for other 3,4-disubstituted sydnones (Hašek et al., 1978, 1979; Ueng et al., 1987a,b, 1989; Ajees et al., 2002). The dihedral angles between the planes of the sydnone ring and the attached phenyl ring in the 3,4-disubstituted sydnone derivatives (55–79°) are larger than those in the 3-substituted sydnone derivatives (2–39°; Ueng et al., 1987a). In (I), the dihedral angle between the planes of the sydnone moiety and the methoxyphenyl ring is 66.32 (10)°. The carbonyl group (C14═O14) is in an s–cis conformation, as can be seen from the torsion angle C16—C15—C14—O14 of −1.5 (4)°. The pentadienone moiety is effectively planar and its mean plane is oriented at angles of 10.98 (17) and 6.57 (18)° with respect to those of the sydnone and methoxyphenyl rings, respectively. The lengths of the C19—C18 [1.462 (4) Å], C18—C17 [1.333 (5) Å], C17—C16 [1.435 (4) Å], C16—C15 [1.330 (4) Å], C15—C14 [1.471 (3) Å], C14—O14 [1.228 (4) Å] and C14—C4 [1.457 (4) Å] bonds indicate conjugation. Atoms H15 and H16; H17 and H18 are trans to each other. The widening of the bond angles C15—C16—C17 [124.3 (3)°], C16—C17—C18 [123.9 (3)°] and C17—C18—C19 [127.2 (3)°] are significantly larger than the normal value of 120°, and this may be due to steric repulsion between atoms H15 and H17 (2.46 Å), between atoms H16 and H18 (2.41 Å), and between atoms H17 and H20 (2.18 Å). A close intramolecular contact between O5 and H15 (2.43 Å) being a repulsive interaction, may have caused the significant opening of the C5—C4—C14 [129.7 (4)°] and C4—C5—O5 [137.3 (3)°].

In the crystal, atom C8 acts as a hydrogen bond donor and forms a weak intermolecular C—H···O interaction with the carbonyl O14 atom of an adjacent molecule, therely linking the molecules into extended chains which have a graph-set motif of C(8) (Bernstein et al., 1995). Atom C11 atom acts as a donor for an intermolecular C—H···O interaction with atom O5 of the sydnone ring of another adjacent molecule. This weak intermolecular interaction also links the molecules into extended chains which have a graph-set motif of C(7) (Bernstein et al., 1995). The above two weak intermolecular C—H···O interactions are combined to form a sheet-like structure which lies parallel to the ab plane (Fig. 2).

S2. Experimental

4-Acetyl-3-(4-methoxy)phenylsydnone (2.34 g, 0.01 mol) was suspended in sodium hydroxide solution (0.5 g sodium hydroxide in 5 ml water and 5 ml e thanol) and benzaldehyde (1 g, 0.01 mol) was added. The reaction mixture was stirred for 30 min at room temperature and the precipitate obtained was collected immediately and washed with water. Recrystallization from acetone and ethanol mixture afforded crystals of (I) suitable for X-ray analysis (m.p. 449–451 K).

S3. Refinement

The methyl H atoms were constrained to an ideal geometry (C—H = 0.98 Å) with U_iso(H) = 1.5U_eq(C), but were allowed to rotate freely about the C—C bonds. All remaining H atoms were placed in geometrically idealized positions (C—H = 0.95 Å) and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C). Although the molecule is achiral, the structure possesses a polar axis. Due to the absence of any significant anomalous scatterers in the compound, the absolute structure was assigned arbitrarily and Friedel pairs were merged before the final refinement. Reflections 001 and 101 were partially obscured by the beam stop and were omitted.

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures

	Fig. 1. View of the molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii.
	Fig. 2. Packing diagram showing C—H···O interactions, viewed down the b axis.

3-(4-Methoxyphenyl)-4-(4-phenyl-1,3-butadienoyl)sydnone

Crystal data

C20H16N2O4	F(000) = 364
Mr = 348.35	Dx = 1.317 Mg m^−3
Monoclinic, P21	Melting point: 449 K
Hall symbol: P 2yb	Mo Kα radiation, λ = 0.71073 Å
a = 12.0961 (8) Å	Cell parameters from 1742 reflections
b = 4.7750 (4) Å	θ = 1.0–25.0°
c = 15.3516 (12) Å	µ = 0.09 mm^−1
β = 97.719 (3)°	T = 160 K
V = 878.66 (12) Å^3	Prism, yellow
Z = 2	0.25 × 0.18 × 0.13 mm

Data collection

Nonius KappaCCD diffractometer	1389 reflections with I > 2σ(I)
Radiation source: Nonius FR590 sealed tube generator	Rint = 0.078
Horizontally mounted graphite crystal monochromator	θmax = 25.0°, θmin = 2.3°
Detector resolution: 9 pixels mm^-1	h = 0→14
ϕ and ω scans with κ offsets	k = 0→5
1752 measured reflections	l = −18→18
1752 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.120	w = 1/[σ^2(Fo^2) + (0.0734P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.001
1752 reflections	Δρmax = 0.18 e Å^−3
237 parameters	Δρmin = −0.17 e Å^−3
1 restraint	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.049 (11)

Special details

Experimental. Solvent used: Acetone-Ethanol Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: glued on a glass fibre Mosaicity (°.): 1.959 (5) Frames collected: 292 Seconds exposure per frame: 52 Degrees rotation per frame: 1.5 Crystal-Detector distance (mm): 30.0

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	0.56558 (17)	−0.6640 (5)	0.98738 (13)	0.0548 (6)
O5	0.51971 (16)	−0.5667 (5)	0.84256 (13)	0.0580 (7)
O12	1.04462 (17)	0.0971 (7)	1.25044 (14)	0.0682 (8)
O14	0.78389 (15)	0.0615 (5)	0.92462 (11)	0.0481 (6)
N2	0.6412 (2)	−0.5766 (6)	1.05647 (16)	0.0554 (8)
N3	0.70059 (19)	−0.3854 (6)	1.02391 (14)	0.0456 (7)
C4	0.6713 (2)	−0.3339 (7)	0.93643 (17)	0.0424 (7)
C5	0.5812 (2)	−0.5154 (8)	0.90953 (19)	0.0489 (8)
C6	0.7893 (2)	−0.2604 (8)	1.08461 (17)	0.0474 (8)
C7	0.8990 (2)	−0.3071 (10)	1.07271 (19)	0.0604 (10)
H7	0.9163	−0.4207	1.0256	0.073*
C8	0.9823 (2)	−0.1874 (10)	1.12980 (19)	0.0614 (11)
H8	1.0582	−0.2195	1.1229	0.074*
C9	0.9559 (2)	−0.0199 (9)	1.1974 (2)	0.0562 (9)
C10	0.8454 (2)	0.0252 (8)	1.20951 (18)	0.0514 (8)
H10	0.8278	0.1396	1.2564	0.062*
C11	0.7609 (2)	−0.0995 (7)	1.15192 (17)	0.0460 (8)
H11	0.6848	−0.0733	1.1592	0.055*
C13	1.0209 (3)	0.2849 (10)	1.3166 (2)	0.0723 (11)
H131	0.9738	0.4374	1.2898	0.108*
H132	1.0907	0.3622	1.3467	0.108*
H133	0.9815	0.1852	1.3590	0.108*
C14	0.7191 (2)	−0.1128 (7)	0.88778 (17)	0.0415 (7)
C15	0.6827 (2)	−0.1097 (7)	0.79242 (17)	0.0462 (8)
H15	0.6338	−0.2529	0.7675	0.055*
C16	0.7156 (2)	0.0855 (8)	0.73964 (17)	0.0454 (7)
H16	0.7651	0.2263	0.7653	0.054*
C17	0.6811 (2)	0.0975 (9)	0.64653 (17)	0.0499 (8)
H17	0.6300	−0.0401	0.6210	0.060*
C18	0.7164 (3)	0.2902 (8)	0.59382 (18)	0.0539 (9)
H18	0.7665	0.4272	0.6211	0.065*
C19	0.6867 (3)	0.3138 (8)	0.49861 (17)	0.0530 (9)
C20	0.6063 (3)	0.1447 (10)	0.45160 (19)	0.0632 (11)
H20	0.5687	0.0078	0.4816	0.076*
C21	0.5802 (3)	0.1741 (10)	0.36056 (19)	0.0683 (12)
H21	0.5255	0.0559	0.3292	0.082*
C22	0.6327 (3)	0.3718 (10)	0.3161 (2)	0.0711 (12)
H22	0.6144	0.3916	0.2542	0.085*
C23	0.7116 (4)	0.5400 (12)	0.3615 (2)	0.0824 (13)
H23	0.7480	0.6776	0.3309	0.099*
C24	0.7396 (3)	0.5127 (10)	0.45278 (19)	0.0706 (11)
H24	0.7949	0.6309	0.4834	0.085*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0601 (13)	0.0478 (14)	0.0600 (12)	0.0008 (12)	0.0206 (10)	0.0054 (12)
O5	0.0555 (12)	0.0631 (17)	0.0565 (12)	−0.0065 (12)	0.0119 (10)	−0.0097 (12)
O12	0.0511 (12)	0.094 (2)	0.0576 (13)	−0.0002 (15)	0.0003 (10)	0.0040 (16)
O14	0.0520 (11)	0.0540 (14)	0.0386 (10)	−0.0036 (12)	0.0067 (8)	0.0035 (10)
N2	0.0580 (15)	0.055 (2)	0.0565 (15)	0.0069 (15)	0.0192 (13)	0.0141 (15)
N3	0.0496 (14)	0.0462 (17)	0.0435 (13)	0.0078 (13)	0.0155 (11)	0.0118 (13)
C4	0.0411 (15)	0.049 (2)	0.0381 (15)	0.0043 (15)	0.0090 (12)	0.0033 (14)
C5	0.0527 (17)	0.0463 (19)	0.0508 (18)	0.0063 (15)	0.0182 (15)	−0.0019 (16)
C6	0.0447 (16)	0.060 (2)	0.0374 (15)	0.0069 (15)	0.0073 (13)	0.0147 (16)
C7	0.0535 (18)	0.089 (3)	0.0402 (15)	0.0208 (19)	0.0108 (14)	0.0110 (18)
C8	0.0461 (17)	0.095 (3)	0.0439 (16)	0.012 (2)	0.0102 (14)	0.015 (2)
C9	0.0460 (17)	0.073 (2)	0.0490 (16)	0.0040 (17)	0.0039 (14)	0.0221 (18)
C10	0.0532 (17)	0.058 (2)	0.0439 (16)	0.0068 (17)	0.0088 (13)	0.0114 (16)
C11	0.0447 (15)	0.055 (2)	0.0399 (14)	0.0074 (16)	0.0107 (12)	0.0120 (16)
C13	0.064 (2)	0.076 (3)	0.073 (2)	−0.006 (2)	−0.0020 (17)	0.008 (2)
C14	0.0388 (14)	0.0465 (19)	0.0403 (15)	0.0024 (15)	0.0097 (12)	0.0027 (16)
C15	0.0461 (16)	0.053 (2)	0.0391 (14)	−0.0006 (16)	0.0046 (12)	0.0013 (16)
C16	0.0476 (15)	0.053 (2)	0.0359 (14)	0.0025 (17)	0.0064 (12)	0.0037 (15)
C17	0.0493 (16)	0.062 (2)	0.0369 (15)	0.0016 (17)	0.0019 (12)	0.0021 (16)
C18	0.0611 (18)	0.060 (2)	0.0410 (15)	0.0050 (17)	0.0079 (13)	0.0100 (16)
C19	0.0606 (18)	0.060 (2)	0.0383 (16)	0.0125 (19)	0.0077 (14)	0.0079 (16)
C20	0.0592 (19)	0.089 (3)	0.0405 (16)	0.012 (2)	0.0043 (14)	0.0117 (19)
C21	0.065 (2)	0.098 (3)	0.0408 (17)	0.023 (2)	0.0001 (15)	0.008 (2)
C22	0.089 (3)	0.087 (3)	0.0384 (17)	0.029 (3)	0.0141 (17)	0.008 (2)
C23	0.120 (3)	0.082 (3)	0.049 (2)	0.009 (3)	0.030 (2)	0.019 (2)
C24	0.101 (3)	0.072 (3)	0.0413 (17)	−0.003 (2)	0.0198 (17)	0.0076 (19)

Geometric parameters (Å, º)

O1—N2	1.369 (3)	C13—H132	0.9800
O1—C5	1.424 (4)	C13—H133	0.9800
O5—C5	1.210 (3)	C14—C15	1.471 (3)
O12—C9	1.375 (4)	C15—C16	1.330 (4)
O12—C13	1.413 (5)	C15—H15	0.9500
O14—C14	1.228 (4)	C16—C17	1.435 (4)
N2—N3	1.303 (4)	C16—H16	0.9500
N3—C4	1.364 (3)	C17—C18	1.333 (5)
N3—C6	1.452 (4)	C17—H17	0.9500
C4—C5	1.411 (5)	C18—C19	1.462 (4)
C4—C14	1.457 (4)	C18—H18	0.9500
C6—C11	1.368 (4)	C19—C24	1.388 (5)
C6—C7	1.381 (4)	C19—C20	1.389 (5)
C7—C8	1.369 (5)	C20—C21	1.398 (4)
C7—H7	0.9500	C20—H20	0.9500
C8—C9	1.382 (5)	C21—C22	1.370 (6)
C8—H8	0.9500	C21—H21	0.9500
C9—C10	1.391 (4)	C22—C23	1.365 (6)
C10—C11	1.392 (4)	C22—H22	0.9500
C10—H10	0.9500	C23—C24	1.402 (4)
C11—H11	0.9500	C23—H23	0.9500
C13—H131	0.9800	C24—H24	0.9500
N2—O1—C5	110.4 (2)	H132—C13—H133	109.5
C9—O12—C13	117.7 (3)	O14—C14—C4	121.9 (2)
N3—N2—O1	105.2 (2)	O14—C14—C15	122.6 (3)
N2—N3—C4	114.9 (3)	C4—C14—C15	115.6 (3)
N2—N3—C6	116.1 (2)	C16—C15—C14	122.6 (3)
C4—N3—C6	129.0 (3)	C16—C15—H15	118.7
N3—C4—C5	105.4 (3)	C14—C15—H15	118.7
N3—C4—C14	124.5 (3)	C15—C16—C17	124.3 (3)
C5—C4—C14	129.7 (2)	C15—C16—H16	117.8
O5—C5—C4	137.3 (3)	C17—C16—H16	117.8
O5—C5—O1	118.5 (3)	C18—C17—C16	123.9 (3)
C4—C5—O1	104.2 (2)	C18—C17—H17	118.1
C11—C6—C7	122.3 (3)	C16—C17—H17	118.1
C11—C6—N3	118.4 (2)	C17—C18—C19	127.2 (3)
C7—C6—N3	119.3 (3)	C17—C18—H18	116.4
C8—C7—C6	119.1 (3)	C19—C18—H18	116.4
C8—C7—H7	120.5	C24—C19—C20	118.2 (3)
C6—C7—H7	120.5	C24—C19—C18	119.4 (3)
C7—C8—C9	119.9 (3)	C20—C19—C18	122.4 (3)
C7—C8—H8	120.1	C19—C20—C21	120.6 (4)
C9—C8—H8	120.1	C19—C20—H20	119.7
O12—C9—C8	116.1 (3)	C21—C20—H20	119.7
O12—C9—C10	123.1 (3)	C22—C21—C20	120.7 (4)
C8—C9—C10	120.9 (3)	C22—C21—H21	119.7
C9—C10—C11	119.1 (3)	C20—C21—H21	119.7
C9—C10—H10	120.5	C23—C22—C21	119.3 (3)
C11—C10—H10	120.5	C23—C22—H22	120.3
C6—C11—C10	118.8 (2)	C21—C22—H22	120.3
C6—C11—H11	120.6	C22—C23—C24	121.0 (4)
C10—C11—H11	120.6	C22—C23—H23	119.5
O12—C13—H131	109.5	C24—C23—H23	119.5
O12—C13—H132	109.5	C19—C24—C23	120.3 (4)
H131—C13—H132	109.5	C19—C24—H24	119.9
O12—C13—H133	109.5	C23—C24—H24	119.9
H131—C13—H133	109.5
C5—O1—N2—N3	−0.1 (3)	O12—C9—C10—C11	179.3 (3)
O1—N2—N3—C4	−0.1 (3)	C8—C9—C10—C11	−0.4 (5)
O1—N2—N3—C6	−179.1 (2)	C7—C6—C11—C10	1.1 (5)
N2—N3—C4—C5	0.2 (3)	N3—C6—C11—C10	−178.9 (3)
C6—N3—C4—C5	179.0 (3)	C9—C10—C11—C6	−0.7 (5)
N2—N3—C4—C14	174.3 (3)	N3—C4—C14—O14	−6.4 (4)
C6—N3—C4—C14	−6.9 (5)	C5—C4—C14—O14	166.2 (3)
N3—C4—C5—O5	179.0 (4)	N3—C4—C14—C15	174.9 (3)
C14—C4—C5—O5	5.3 (6)	C5—C4—C14—C15	−12.5 (4)
N3—C4—C5—O1	−0.2 (3)	O14—C14—C15—C16	−1.5 (4)
C14—C4—C5—O1	−173.9 (3)	C4—C14—C15—C16	177.3 (3)
N2—O1—C5—O5	−179.2 (3)	C14—C15—C16—C17	−179.3 (3)
N2—O1—C5—C4	0.2 (3)	C15—C16—C17—C18	−178.4 (3)
N2—N3—C6—C11	−66.6 (4)	C16—C17—C18—C19	179.0 (3)
C4—N3—C6—C11	114.6 (3)	C17—C18—C19—C24	−174.0 (3)
N2—N3—C6—C7	113.4 (3)	C17—C18—C19—C20	6.4 (5)
C4—N3—C6—C7	−65.4 (5)	C24—C19—C20—C21	0.4 (5)
C11—C6—C7—C8	−0.4 (5)	C18—C19—C20—C21	179.9 (3)
N3—C6—C7—C8	179.6 (3)	C19—C20—C21—C22	−0.6 (6)
C6—C7—C8—C9	−0.8 (6)	C20—C21—C22—C23	0.3 (6)
C13—O12—C9—C8	175.8 (3)	C21—C22—C23—C24	0.1 (6)
C13—O12—C9—C10	−4.0 (5)	C20—C19—C24—C23	0.1 (6)
C7—C8—C9—O12	−178.5 (4)	C18—C19—C24—C23	−179.5 (4)
C7—C8—C9—C10	1.2 (5)	C22—C23—C24—C19	−0.3 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···O14^i	0.95	2.38	3.281 (4)	159
C11—H11···O5^ii	0.95	2.47	3.410 (3)	170

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