3-Hydroxy-1-[(morpholin-4-yl)methyl]pyridazin-6(1H)-one

In the title compound, C9H13N3O3, the morpholine ring adopts a chair conformation and its mean plane makes a dihedral angle of 68.00 (11)° with the pyridazine ring. The carbonyl O atom deviates from the plane of the pyridazine ring by 0.0482 (12) Å. An intramolecular C—H⋯O hydrogen bond occurs. In the crystal, molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds, forming chains along [1-10].

In the title compound, C 9 H 13 N 3 O 3 , the morpholine ring adopts a chair conformation and its mean plane makes a dihedral angle of 68.00 (11) with the pyridazine ring. The carbonyl O atom deviates from the plane of the pyridazine ring by 0.0482 (12) Å . An intramolecular C-HÁ Á ÁO hydrogen bond occurs. In the crystal, molecules are linked by O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, forming chains along [110].

Experimental
The new Mannich base morpholino methyl maleic hydrazide(MMMH) was synthesised by introducing morpholino methyl moiety in place of active hydrogen atom attached to nitrogen of maleic hydrazide through Mannich reaction. An equimolar mixture of maleic hydrazide (11.20 g), formaldehyde (3.00 g) and morpholine (8.7 g) was dissolved in 400 ml of ethanol and refluxed for about 5 hours. The formation of the product MMMH and the completion of the reaction was identified by the formation of a clear solution. The resulting solution was concentrated to 200 ml by distillation under reduced pressure. The concentrate on cooling yielded a colourless crystalline solid, the crude product (20.6g) that was first washed with ethanol and then ether and dried in vacuum oven. The compound MMMH was dissolved in hot ethanol and the homogeneous solution was allowed to evaporate slowly. After two weeks the colourless crystalline solid separated out which was washed with minimum amount of ethanol and then dried in a vaccum oven; a crystal was chosen for X-ray diffraction studies from this sample.

Refinement
All C-bound H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 and 0.97 Å, for aryl and methylene H-atoms, respectively. The hydroxyl H-atoms were included at geometrically calculated positions with O-H = 0.82 Å. The H-atoms are constrained to ride on their parent atoms, with U iso (H) = 1.2 times U eq (C/O).

Figure 2
The crystal packing of the title compound viewed down a axis. H-atoms not involved in H-bonds have been excluded for clarity. Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq C1 0.2321 (