Condensation products of Betti base and pyridinecarboxaldehydes

Previously unknown condensation products were obtained by the reaction of the racemic Betti base with 2-, 3- and 4-pyridinecarboxaldehydes. It was established that they have a naphthoxazine structure in solid state. In the solution, a three-component ring-chain equilibrium is established between the imine form and cis- and trans-oxazines. Over time or under heating, these compounds are prone to 2-azaallylic prototropic tautomerism, involving 1-(phenyl- (pyridinylmethylimino)methyl)naphthalen-2-ols in equilibrium.