Crystal structure of 1-[(2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazin-2-yl)methyl]naphthalen-2-ol: a possible candidate for new polynaphthoxazine materials

A novel naphthoxazine has been synthesized and structurally characterized. In the crystal, pairs of inversion-related molecules are linked into inversion dimers via C—H⋯π interactions.


Chemical context
Benzoxazines and naphthoxazines have been shown to polymerize via a thermally induced ring-opening reaction of the oxazine ring to form a phenolic structure associated with traditional phenolic resins (Ishida & Sanders, 2001). Polybenzoxazines, polynaphthoxazines and their derivatives are a class of phenolic resins which are alternative to the traditional resins (Yildirim et al., 2006). So far the main contribution to the chemistry of these compounds has been the work of Burke (Burke, 1949;Burke et al., 1952), who was the first to show that aromatic oxazines could be obtained via Mannich-type condensation-cyclization reactions of certain phenols or naphtols with formaldehyde and primary amines in the molar ratio of 1:2:1. Various methods have been reported for the synthesis of dihydro-1,3-oxazines including the reaction under neat conditions via Mannich-type condensation-cyclization reaction of phenols or naphthols with formaldehyde and primary amines (Mathew et al., 2010). Our current research includes synthesis and characterization of monofunctional benzoxazines using aminals as performed Mannich electrophiles instead of formaldehyde and primary amines. Earlier (Rivera et al., 2005), we have reported an interesting behaviour of the macrocyclic aminal 1, 3,6,8-tetraazatricyclo-[4.4.1.1 3,8 ]dodecane (TATD) with hindered meta-disubstituted phenols affording 3,3-ethylene-bis(3,4-dihydro-2H-1,3-benzoxazines) with good yields by a Mannich-type reaction in basic media. Recently, we synthesized the title compound by a reaction between the cyclic aminal 1, 3,6,8-tetraazatricyclo[4.3.1.1. 3,8 ]undecane (TATU) with 2-naphthol solventfree at low temperature. Because a wide range of cured properties can be obtained (Uyar et al., 2008) depending on the structure of aryloxazine monomers, initiators and the curing conditions, the title compound is a very good candidate as a monomer for the investigation of the polymerization of this class of compounds.

Figure 2
An inversion dimer in the crystal of the title compound, with C-HÁ Á Á interactions indicated by dashed lines.
three-dimensional network. The unit-cell packing is shown in Fig. 4.

Database survey
The 2 The values of the title compound fit very well into these ranges:

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were located in a The view of the column structure along the a axis, showing thestacking interactions (dashed lines).