The ring-chain tautomerism of the condensation products of o-hydroxybenzylamine with a number of aldehydes and ketones was studied by infrared and nuclear magnetic resonance spectroscopy. Substituted benzaldehydes give rise to products which in the crystalline state are Schiff bases (chain) but which rapidly equilibrate in solution to a mixture of Schiff base and 3, 4-dihydro-2H-1, 3-benzoxazine (ring) tautomers. The ring-chain ratio depends on ...
