(E)-3-[(2-Hydroxynaphthalen-1-yl)methylideneamino]-5-(morpholin-4-ylmethyl)-1,3-oxazolidin-2-one

The title compound, C19H21N3O4, crystallizes with two independent molecules in the asymmetric unit. In both molecules, there is an intramolecular O—H⋯N hydrogen bond, which correlates with the fact that each molecule adopts an E configuration with respect to the C=N bond. In the crystal, there are C—H⋯O and C—H⋯π interactions present.


Related literature
Cg3 is the centroid of the C10-C14/C19 ring.

Comment
The naphthalene group as a fluorophore has been studied extensively due to its characteristic photophysical properties and the competitive stability in the environment (Li et al., 2010;Iijima et al., 2010). As part of an ongoing study of such compounds based on the naphthalene group (Xu et al., 2009;Liu et al., 2011), we report herein on the crystal structure of the title compound.
The molecular structure of the two independent molecules (A and B) of the title compound is shown in Fig. 1. Both molecules display a trans configuration about the C═N bond. The bond distances are within the normal range (Allen et al., 1987). In each molecule there is an intramolecular N-H···O hydrogen bond (Table 1), graph set S(5) (Bernstein et al., 1995), and the oxazolidine rings have chair conformations.
In the crystal molecules are linked via C-H···O and C-H···π interactions (Table 1).

Experimental
A solution of 3-amino-5-(morpholinomethyl)oxazolidin-2-one (0.10 g, 0.5 mmol) in 5 ml of ethanol was added slowly to a solution of 2-hydro-1-naphthaldehyde (0.086 g,1 mmol) in 10 ml of absolute ethanol under heating and stirring. The mixture was then refluxed for 2 h. The mixture was then cooled to room temperature and the resulting solution was left to stand in air for 15 days. Colourless needle-shaped crystals of the title compound were formed, on slow evaporation of the solvent.

Refinement
All H-atoms were placed in calculated positions and treated as riding: O-H = 0.82 Å, C-H = 0.93, 0.97 and 0.98 Å, for CH(allyl and aromatic), CH 2 and CH(methine) H-atoms, respectively, with U iso (H) = k × U eq (O,C), where k = 1.5 for OH H-atoms, and k = 1.2 for all other H-atoms.  Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles 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 > σ(F 2 ) is used only for calculating Rfactors(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.