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In the title compound, C10H9N3O, the pyridazinone moiety is essentially planar and forms a dihedral angle of 49.5 (1)° with the phenyl substituent. The molecular packing is stabilized by van der Waals interactions and hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199015231/sk1336sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270199015231/sk1336Isup2.hkl
Contains datablock I

CCDC reference: 143251

Comment top

It is known that 6-aryl-3(2H)-pyridazinones and their 4,5-dihydro derivatives display several pharmacological activities, all of them related to cardiotonics, such as reduction of blood pressure, inhibition of platelet aggregation, positive inotropic activity, and others (Robertson et al., 1986). Likewise, 6-arylpyridazinones with nitro and acyl substituents at the 4- and 5- positions show good antiaggregating properties (Schudt et al., 1991). We have previously reported the synthesis of 5-aminomethyl-6-aryl-4,5-dihydropyridazinones and 6-aryl-5-aminomethyl-3(2H)-pyridazinones (Raviña et al., 1990). Some of these compounds show a good in vitro inhibitory activity on ADP-induced rat platelet aggregation. As a continuation of this previous report on the chemistry and pharmacology of this class of compounds, we carried out the crystal structure determination of 5-amino-6-phenyl-1,6-dihydropyridazin-3(2H)-one, (I). This enamine-like compound can be employed in the synthesis of hetero-condensed pyridazinones. Recently, we used this compound as an intermediate in the synthesis of pyrido[2,3-d]pyridazines (Pita et al., 1999). \scheme

There are no unusual bond distances and angles in (I), and they are in the range of calculated values using the AM1 method in related structures (Estevez et al., 1998). The bond lengths in the pyridazinone ring range from 1.304 (2) to 1.450 (3) Å. The torsion angle between the pyridazinone and the phenyl ring, found using the quantum chemical AM1 method in MOPAC (Stewart, 1990?) for the lower energy conformations, is in the range 40–140°, with a heat of formation of 38.30 Kcalmol-1. In the crystal structure this angle is -51.3 (3)°, which corresponds to the minimum in the energy calculations. The calculated favoured conformation of the enol form corresponds to torsion angles in the same range (40–140°) and a heat of formation of 34.20 Kcalmol-1, which shows that this enol is the predominant form at equilibrium. This is contrary to the fact that in the crystal the molecule is present in the amide form, which corresponds to a higher heat of formation. The dihedral angle between the respective least-squares planes of the pyridazinone ring and the phenyl ring is 49.5 (1)°. The mean Csp2—Csp2 bond length within the phenyl ring is 1.382 (1) Å.

The N3 atom of the amine and the N1 atom of the amide group in the pyridazinone ring are involved in two intermolecular hydrogen bonds with a neighbouring O1, forming an infinite two-dimensional network in the plane (001).

Experimental top

A suspension of 5-bromo-6-phenyl-3(2H)-pyridazinone (0.5 g, 1.9 mmol), ammonium chloride (0.3 g, 5.6 mmol) and ammonium hydroxide (50 ml) was heated at 458 K at pressure of 374 psi (1psi 6.895 kPa) for 3 h in a Parr reactor. The mixture was evaporated in vacuo and washed with ammonium hydroxide, and the solid obtained, (I), was recrystallized from ethanol (yield 70%; m.p. 517 K). Spectroscopic analysis: IR (KBr), cm-1: 3480–3425 (NH), 1670 (CO); 1H NMR (DMSO-δ6, p.p.m.): δ d 12.12 (s, 1H, NH, deuterium oxide exchangeable), 7.50–7.43 (m, 5H, aromatics), 5.71 (s, 1H, CH—CO), 5.96 (s, 2H, NH2); 13C NMR, p.p.m.: d 162.5 (C3), 99.1 (C4), 149.2 (C5), 140.1 (C6), 134.4 (C1'), 129.1 (C2', C6'), 128.8 (C3', C5'), 129.1 (C4'); analysis calculated: C 64.16, H 4.85, N 22.45%; found: C 64.20, H 4.78, N 22.43%.

Refinement top

H atoms were calculated geometrically and included in the refinement, but were restrained to ride on their parent atoms, with isotropic displacement parameters fixed to 1.3 times Ueq of their parent atoms.

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997b); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: DIAMOND (Bergerhoff, 1996); software used to prepare material for publication: PLATON (Spek, 1990), PARST (Nardelli, 1983, 1995) and PARSTCIF (Nardelli, 1992).

Figures top
[Figure 1] Fig. 1. A plot of (I) showing the atomic numbering scheme. Displacement ellipsoids are drawn at 50% probability level, and H atoms are shown as spheres of arbitrary radii.
5-Amino-6-phenyl-1,6-dihydropyridazin-3(2H)-one top
Crystal data top
C10H9N3OF(000) = 784
Mr = 187.20Dx = 1.309 Mg m3
Orthorhombic, PbcaCu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2ac 2abCell parameters from 25 reflections
a = 8.752 (2) Åθ = 10.8–28.1°
b = 10.525 (5) ŵ = 0.73 mm1
c = 20.619 (5) ÅT = 293 K
V = 1899.3 (11) Å3Prism, light green
Z = 80.48 × 0.20 × 0.14 mm
Data collection top
Siemens P4 four-circle
diffractometer
1102 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.024
Graphite monochromatorθmax = 57.2°, θmin = 4.3°
2θ/ω scansh = 19
Absorption correction: ψ-scan
(North et al., 1968)
k = 111
Tmin = 0.626, Tmax = 0.903l = 122
1733 measured reflections3 standard reflections every 100 reflections
1266 independent reflections intensity decay: <1.0%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: FullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.104 w = 1/[σ2(Fo2) + (0.0532P)2 + 0.757P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max = 0.002
1266 reflectionsΔρmax = 0.14 e Å3
128 parametersΔρmin = 0.14 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997a), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0110 (8)
Crystal data top
C10H9N3OV = 1899.3 (11) Å3
Mr = 187.20Z = 8
Orthorhombic, PbcaCu Kα radiation
a = 8.752 (2) ŵ = 0.73 mm1
b = 10.525 (5) ÅT = 293 K
c = 20.619 (5) Å0.48 × 0.20 × 0.14 mm
Data collection top
Siemens P4 four-circle
diffractometer
1102 reflections with I > 2σ(I)
Absorption correction: ψ-scan
(North et al., 1968)
Rint = 0.024
Tmin = 0.626, Tmax = 0.903θmax = 57.2°
1733 measured reflections3 standard reflections every 100 reflections
1266 independent reflections intensity decay: <1.0%
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.104H-atom parameters constrained
S = 1.10Δρmax = 0.14 e Å3
1266 reflectionsΔρmin = 0.14 e Å3
128 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. The structure was solved by direct methods and Fourier synthesis. Non-H atoms were refined anisotropically by full-matrix least-squares techniques.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.11598 (15)0.12824 (13)0.02499 (7)0.0510 (5)
N10.17603 (17)0.02452 (14)0.04753 (7)0.0394 (5)
N20.26660 (17)0.08609 (15)0.08973 (7)0.0385 (5)
N30.59357 (19)0.12476 (17)0.08433 (9)0.0503 (6)
C10.2131 (2)0.08360 (17)0.01433 (9)0.0361 (6)
C20.3567 (2)0.13477 (17)0.02767 (9)0.0375 (6)
C30.4539 (2)0.07773 (17)0.07128 (9)0.0348 (6)
C40.4014 (2)0.03863 (17)0.10159 (8)0.0346 (6)
C50.4959 (2)0.11395 (19)0.14795 (9)0.0387 (6)
C60.5656 (3)0.0585 (2)0.20123 (10)0.0550 (8)
C70.6450 (3)0.1341 (3)0.24540 (12)0.0736 (10)
C80.6569 (3)0.2625 (3)0.23604 (13)0.0767 (10)
C90.5887 (3)0.3180 (3)0.18367 (12)0.0635 (9)
C100.5084 (2)0.2448 (2)0.13948 (10)0.0481 (7)
H10.086720.055950.040810.0512*
H20.387290.208760.006710.0487*
H3A0.624580.192590.065150.0654*
H3B0.651790.086990.111840.0654*
H60.559370.028840.207540.0715*
H70.690380.096980.281520.0957*
H80.711410.311960.265380.0999*
H90.596210.405360.177650.0826*
H100.462550.283330.103860.0626*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0381 (8)0.0439 (9)0.0709 (10)0.0002 (6)0.0115 (7)0.0187 (7)
N10.0320 (9)0.0355 (10)0.0506 (9)0.0025 (7)0.0050 (7)0.0081 (7)
N20.0359 (9)0.0363 (9)0.0432 (9)0.0014 (7)0.0036 (7)0.0069 (7)
N30.0392 (10)0.0461 (11)0.0657 (12)0.0100 (8)0.0110 (8)0.0147 (9)
C10.0352 (10)0.0274 (10)0.0458 (11)0.0048 (8)0.0012 (8)0.0030 (8)
C20.0359 (10)0.0268 (10)0.0498 (11)0.0001 (8)0.0026 (9)0.0050 (8)
C30.0329 (10)0.0302 (10)0.0412 (10)0.0002 (8)0.0019 (8)0.0031 (8)
C40.0363 (11)0.0315 (11)0.0361 (10)0.0006 (8)0.0001 (8)0.0008 (8)
C50.0345 (10)0.0429 (12)0.0388 (10)0.0018 (9)0.0005 (8)0.0050 (9)
C60.0555 (13)0.0609 (14)0.0485 (12)0.0034 (12)0.0095 (10)0.0031 (11)
C70.0655 (16)0.100 (2)0.0552 (14)0.0064 (15)0.0222 (12)0.0095 (15)
C80.0595 (16)0.096 (2)0.0746 (18)0.0097 (15)0.0132 (13)0.0373 (16)
C90.0577 (14)0.0575 (15)0.0754 (16)0.0120 (12)0.0010 (13)0.0252 (13)
C100.0478 (12)0.0457 (13)0.0508 (12)0.0003 (10)0.0003 (9)0.0097 (10)
Geometric parameters (Å, º) top
O1—C11.265 (2)C5—C101.393 (3)
N1—N21.344 (2)C5—C61.385 (3)
N1—C11.367 (2)C6—C71.395 (4)
N2—C41.304 (2)C7—C81.369 (4)
N3—C31.346 (3)C8—C91.365 (4)
N1—H10.8600C9—C101.385 (3)
N3—H3A0.8601C2—H20.9300
N3—H3B0.8599C6—H60.9300
C1—C21.395 (3)C7—H70.9301
C2—C31.376 (3)C8—H80.9298
C3—C41.450 (3)C9—H90.9301
C4—C51.492 (3)C10—H100.9300
O1···N3i2.880 (3)C5···H7vii3.0490
O1···C2i3.373 (3)C6···H3B2.5122
O1···N1ii2.818 (2)C9···H6viii3.0512
O1···H2i2.6629C9···H3Bix2.8900
O1···H3Ai2.0609H1···O1ii1.9577
O1···H1ii1.9577H1···C1ii2.8745
O1···H10iii2.8978H1···H1ii2.5541
N1···O1ii2.818 (2)H1···H2iv2.5843
N2···C2iv3.381 (3)H2···H3A2.4070
N3···C63.097 (3)H2···O1vi2.6629
N3···C1v3.437 (3)H2···H1iii2.5843
N3···O1vi2.880 (3)H3A···H22.4070
N2···H7vii2.7396H3A···O1vi2.0609
N2···H102.7084H3A···C1vi2.9723
N3···H62.7500H3B···C52.6246
C1···N3v3.437 (3)H3B···C62.5122
C2···N2iii3.381 (3)H3B···H62.2187
C2···C3v3.451 (3)H3B···C9x2.8900
C2···C4v3.551 (3)H3B···H9x2.5908
C2···O1vi3.373 (3)H6···N32.7500
C3···C2v3.451 (3)H6···C33.0017
C3···C3v3.460 (3)H6···H3B2.2187
C4···C2v3.551 (3)H6···C9xi3.0512
C6···N33.097 (3)H7···N2xii2.7396
C1···H1ii2.8745H7···C4xii3.0979
C1···H10iii2.7808H7···C5xii3.0490
C1···H3Ai2.9723H9···H3Bix2.5908
C3···H63.0017H10···N22.7084
C4···H7vii3.0979H10···O1iv2.8978
C5···H3B2.6246H10···C1iv2.7808
N2—N1—C1125.86 (15)C4—C5—C10119.25 (17)
N1—N2—C4118.06 (15)C5—C6—C7119.8 (2)
N2—N1—H1117.07C6—C7—C8120.6 (2)
C1—N1—H1117.08C7—C8—C9120.0 (3)
C3—N3—H3A119.99C8—C9—C10120.3 (3)
H3A—N3—H3B120.00C5—C10—C9120.5 (2)
C3—N3—H3B120.00C1—C2—H2119.41
O1—C1—C2126.04 (17)C3—C2—H2119.42
N1—C1—C2115.88 (16)C5—C6—H6120.10
O1—C1—N1118.07 (16)C7—C6—H6120.11
C1—C2—C3121.17 (17)C6—C7—H7119.73
N3—C3—C2122.12 (17)C8—C7—H7119.67
N3—C3—C4120.82 (16)C7—C8—H8120.00
C2—C3—C4117.03 (16)C9—C8—H8119.96
C3—C4—C5123.32 (16)C8—C9—H9119.85
N2—C4—C5114.71 (16)C10—C9—H9119.87
N2—C4—C3121.97 (16)C5—C10—H10119.76
C4—C5—C6121.89 (18)C9—C10—H10119.74
C6—C5—C10118.78 (18)
C1—N1—N2—C41.3 (3)C3—C4—C5—C10132.03 (19)
N2—N1—C1—O1178.29 (16)N2—C4—C5—C6129.2 (2)
N2—N1—C1—C21.9 (3)N2—C4—C5—C1047.5 (2)
N1—N2—C4—C30.7 (2)C3—C4—C5—C651.3 (3)
N1—N2—C4—C5178.87 (15)C4—C5—C6—C7176.1 (2)
O1—C1—C2—C3179.65 (19)C10—C5—C6—C70.6 (3)
N1—C1—C2—C30.6 (3)C4—C5—C10—C9176.60 (19)
C1—C2—C3—N3179.27 (18)C6—C5—C10—C90.2 (3)
C1—C2—C3—C41.1 (3)C5—C6—C7—C81.1 (4)
N3—C3—C4—N2180.00 (1)C6—C7—C8—C91.0 (4)
C2—C3—C4—C5177.67 (17)C7—C8—C9—C100.6 (4)
N3—C3—C4—C50.5 (3)C8—C9—C10—C50.1 (3)
C2—C3—C4—N21.8 (3)
Symmetry codes: (i) x1/2, y+1/2, z; (ii) x, y, z; (iii) x+1/2, y+1/2, z; (iv) x+1/2, y1/2, z; (v) x+1, y, z; (vi) x+1/2, y+1/2, z; (vii) x1/2, y, z1/2; (viii) x+1, y1/2, z1/2; (ix) x+3/2, y1/2, z; (x) x+3/2, y+1/2, z; (xi) x+1, y+1/2, z1/2; (xii) x+1/2, y, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1ii0.861.962.818 (2)180
N3—H3A···O1vi0.862.062.880 (3)159
Symmetry codes: (ii) x, y, z; (vi) x+1/2, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC10H9N3O
Mr187.20
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)293
a, b, c (Å)8.752 (2), 10.525 (5), 20.619 (5)
V3)1899.3 (11)
Z8
Radiation typeCu Kα
µ (mm1)0.73
Crystal size (mm)0.48 × 0.20 × 0.14
Data collection
DiffractometerSiemens P4 four-circle
diffractometer
Absorption correctionψ-scan
(North et al., 1968)
Tmin, Tmax0.626, 0.903
No. of measured, independent and
observed [I > 2σ(I)] reflections
1733, 1266, 1102
Rint0.024
θmax (°)57.2
(sin θ/λ)max1)0.545
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.104, 1.10
No. of reflections1266
No. of parameters128
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.14, 0.14

Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXS97 (Sheldrick, 1997b), SHELXL97 (Sheldrick, 1997a), DIAMOND (Bergerhoff, 1996), PLATON (Spek, 1990), PARST (Nardelli, 1983, 1995) and PARSTCIF (Nardelli, 1992).

Selected geometric parameters (Å, º) top
O1—C11.265 (2)N3—C31.346 (3)
N1—N21.344 (2)C1—C21.395 (3)
N1—C11.367 (2)C2—C31.376 (3)
N2—C41.304 (2)C3—C41.450 (3)
N2—N1—C1125.86 (15)N3—C3—C2122.12 (17)
N1—N2—C4118.06 (15)N3—C3—C4120.82 (16)
O1—C1—C2126.04 (17)N2—C4—C5114.71 (16)
N1—C1—C2115.88 (16)N2—C4—C3121.97 (16)
O1—C1—N1118.07 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.861.962.818 (2)180
N3—H3A···O1ii0.862.062.880 (3)159
Symmetry codes: (i) x, y, z; (ii) x+1/2, y+1/2, z.
 

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