3,3′-(Ethane-1,2-diyl)bis(6-methoxy-3,4-dihydro-2H-1,3-benzoxazine) monohydrate

The asymmetric unit of the title compound, C20H24N2O4·H2O, contains one half-organic molecule (an inversion centre generates the other half of the molecule) and a half-molecule of water (the O atom has site symmetry 2). The near planarity of the fused-benzene ring is illustrated by the very small deviations of all the atoms from the plane [largest deviation = 0.0092 (11) Å. The six-membered N,O-containing ring adopts a half-chair conformation. The observed N—CH2 and CH2—O bond lengths can be correlated to the manifestation of an anomeric effect in the N—CH2—O unit. In the crystal, the molecules are connected into zigzag chains parallel to [001] through O—H⋯N hydrogen bonds formed between the oxazinic N atom and the solvent water molecule. The chains are consolidated by C—H⋯O interactions.

The asymmetric unit of the title compound, C 20 H 24 N 2 O 4 ÁH 2 O, contains one half-organic molecule (an inversion centre generates the other half of the molecule) and a half-molecule of water (the O atom has site symmetry 2). The near planarity of the fused-benzene ring is illustrated by the very small deviations of all the atoms from the plane [largest deviation = 0.0092 (11) Å . The six-membered N,O-containing ring adopts a half-chair conformation. The observed N-CH 2 and CH 2 -O bond lengths can be correlated to the manifestation of an anomeric effect in the N-CH 2 -O unit. In the crystal, the molecules are connected into zigzag chains parallel to [001] through O-HÁ Á ÁN hydrogen bonds formed between the oxazinic N atom and the solvent water molecule. The chains are consolidated by C-HÁ Á ÁO interactions.
The asymmetric unit of the title compound ( (Rivera et al., 2010). In contrast to the chloro analog, the title compound was found to be more agreement with other related structures (Rivera et al., 2012(Rivera et al., , 2011, and with the normal values for O-CH 2 (1.470) and CH 2 -N (1.469) (Allen et al., 1987), indicating that the methoxy substituent decrease the influence of stereoelectronic effects in the N-CH 2 -O moiety.
In the crystal structure, the molecules of the title compound are conected into zigzag chains parallel to [001] through O -H···N hydrogen bonds formed between its oxazinic N atom and the solvent water molecule. This chain is further stabilized by weak C-H···O hydrogen bonding interactions between H4 and O1. (Figure 2)

Experimental
The title compound was synthesized according to the literature procedure (Rivera et al.,1989), and the single crystals were obtained by slow evaporation from a ethanol/water solvent mixture at room temperature.

Refinement
All hydrogen atoms were discernible in difference Fourier maps and could be refined to reasonable geometry. According to common practice the hydrogen atoms attached to carbons were kept in ideal positions with C-H distance 0.96%A during the refinement. The methyl H atoms were allowed to rotate freely about the adjacent C-C bonds. The coordinates of the hydrogen atom bonded to oxygen were refined freely. All H atoms were refined with displacement coefficients supplementary materials sup-2 Acta Cryst. (2012). E68, o2734 U iso (H) set to 1.5U eq (C, O) for the methyl-and hydroxyl groups and to 1.2Ueq(C) for the CH-, and CH 2 -groups.

Figure 1
A view of (I) with the numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. In the organic molecule, the labelled atoms are related with unlabelled atoms by symmetry code [1-x, 1-y, 1-z]. In the water molecule the labelled atom is related with unlabelled atom by symmetry code [1-x,y,3/2-z]. The hydrogen bond interaction is shown as dashed lines.  Special details Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F 2 for refinement carried out on F and F 2 , respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement. The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.