N-(4-Methoxyphenyl)-2,6-dimethyl-1,3-dioxan-4-amine

In the title compound, C13H19NO3, the dioxane ring adopts a chair conformation. Its mean plane is inclined to the 4-methoxyphenyl ring by 70.34 (9)°. In the crystal, molecules are linked by pairs of C—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(16) ring motif. The dimers are linked via C—H⋯π interactions, forming two-dimensional networks lying parallel to the ac plane.

In the title compound, C 13 H 19 NO 3 , the dioxane ring adopts a chair conformation. Its mean plane is inclined to the 4methoxyphenyl ring by 70.34 (9) . In the crystal, molecules are linked by pairs of C-HÁ Á ÁO hydrogen bonds, forming inversion dimers with an R 2 2 (16) ring motif. The dimers are linked via C-HÁ Á Á interactions, forming two-dimensional networks lying parallel to the ac plane.

Comment
Oxygen heterocycles play a vital role as basic building blocks in pharmaceutical preparations. Dioxane rings are frequently encountered in many bioactive molecules, such as cytotoxic agents (Aubele et al., 2005) and antimuscarinic agents (Marucci et al., 2005). This class of compounds also has useful insecticidal as well as anti-foaming properties (Yuan et al., 2005;Wang et al., 1994Wang et al., , 1996a. In view of the different applications of this class of compounds, we have synthesized the title derivative and report herein on its crystal structure. In the title molecule, Fig. 1, the dioxane ring (O2/O3/C8-C11) adopts a chair conformation and its mean plane makes a dihedral angle of 70.34 (9)° with the benzene ring (C2-C7).
In the crystal, molecules are linked by pairs of C-H···O hydrogen bonds (Table 1 and Fig. 2) forming inversion dimers with an R 2 2 (16) ring motif (Bernstein et al., 1995). The dimers are linked via C-H···π interactions forming twodimensional networks lying parallel to the ac plane (Table 1).

Experimental
To 4-anisidine (1 mmol), acetaldehyde (3 mmol) was added drop wise and stirred for about 4 h at 273 K. The progress of the reaction was monitored by TLC. The reaction mixture was then washed with petroleum ether. The residue was dissolved in diethylether and the solution left for the solvent to evaporate. The solid product obtained was recrystallized from diethylether giving block-like colourless crystals of the title compound.

Refinement
The NH H atom was located in a difference Fourier map and freely refined. The C-bound H atoms were placed in calculated positions refined as riding: C-H = 0.93 Å to 0.98 Å with U iso (H) = 1.5U eq (C-methyl) and = 1.2U eq (C) for other H atoms.

Figure 2
The crystal packing of the title compound viewed almost perpendicular to (011). Hydrogen bonds are shown as dashed lines (see Table 1 for details; H-atoms not involved in hydrogen bonding have been omitted for clarity).  N-(4-Methoxyphenyl)-2,6-dimethyl-1,3-

Special details
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 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.