Combining naphthoxazines and benzoxazines for non-symmetric curable oxazines by one-pot synthesis

Herewith, we report a novel approach to combine two structurally diverse oxazines, namely benzoxazine and naphthoxazine, on a same molecule by one-pot two step approach. The approach is based on higher room temperature reactivity of 2-naphthols towards Mannich reaction compared to phenols. Thus, primary amine functional naphthoxazine intemediates could be prepared at low temperatures by using diamines. Phenols were added in the second step for further heating to combine naphthoxazine and benzoxazine groups on a scaffold. Moreover, main-chain oligobenzoxazine with side chain naphthoxazines was successfully prepared by this method. The spectral and thermal characterizations was performed and compared with model dibenzoxazine and dinaphthoxazine compounds. It was shown that synthesis of these naphthoxazine-benzoxazine anti-symmetric oxazines are as straight forward as classical benzoxazine synthesis.