4-(2-Hydroxybenzylidene)-3-methylisoxazol-5(4H)-one

The molecular skeleton of the title molecule, C11H9NO3, is approximately planar (r.m.s. deviation = 0.0056 Å); the two rings form a dihedral angle of 6.5 (1)°. In the crystal structure, intermolecular O—H⋯N hydrogen bonds involving the H atom of the hydroxy group and the N atom of the isoxazole ring link molecules into chains running along the c axis.

The molecular skeleton of the title molecule, C 11 H 9 NO 3 , is approximately planar (r.m.s. deviation = 0.0056 Å ); the two rings form a dihedral angle of 6.5 (1) . In the crystal structure, intermolecular O-HÁ Á ÁN hydrogen bonds involving the H atom of the hydroxy group and the N atom of the isoxazole ring link molecules into chains running along the c axis.
We are grateful to the Foundation of Jiangsu Key Laboratory of Marine Biotechnology for financial support (grant No. 2007HS009).

Comment
Arylmethylene isoxazolone derivatives are effective anti-psychotics in the treatment of depression and schizophrenia. The study about arylmethylene isoxazolone derivatives mainly concentrates in the biological activities (Ishioka et al., 2002;Liu et al., 2005). However, structural studies of them have rarely been reported. As a part of our investigation on arylmethylene isoxazolone derivatives, we report here the structure of the title compound, (I), synthesized by three component condensation reaction of methyl acetoacetate, hydroxylamine with salicylaldehyde in aqueous media under ultrasonic irradiation.
In (I) (Fig. 1), all bond lengths and angles agree well with those reported for the related compounds (Cocivera et al., 1976;Villemin et al., 1993;Zhang et al., 2008). The molecular structure adopts a Z-configuration about the C2=C5 double bond. The hydroxy groups and the isoxazol groups are involved in intermolecular O-H···N hydrogen bonds (Table 1), which link the molecules into chain structure, hydroxy O atom in the molecule acts as hydrogen-bond donor to isoxazol N atom in the neighbouring molecule, so forming a chain structure.

Experimental
A mixture of methyl acetoacetate (4 mol), hydroxylamine hydrochloride (4 mmol), and pyridine(4 mmol) in distilled water(10 ml) was irradiated in the water bath of an ultrasonic cleaner for 10 min., then salicylaldehyde(4 mmol) was slowly added to the mixture. The resulting mixture was irradiated in the water bath of an ultrasonic cleaner for 1.5 h. The solution was left at room temperature overnight, the obtained mushy solution was filtered and the solid was washed with cold water and ethanol. The crude product was recrystallized from ethanol to afford the desired product as a yellow solid. Single crystal of (I) were obtained by slow evaporation of aqueous ethanol(95%) solution at ambient temperature after 7 d. Elemental analysis, calculated for C11 H9 N O3: C 65.02, H 4.46, N 6.89%; found: C 65.09. H 4.49, N 6.92%.