The reversible intramolecular addition of a hydroxy group to a C= N double bond to form a cyclic structure is a well-known phenomenon among N-unsubstituted 1, 3-O, N-heterocycles. This ring-chain tautomeric process influences the reactivity and therefore the synthetic applicability of these compounds [1]. The reduction of ring-chain tautomeric 1, 3-O, N- heterocycles is a method that has often been applied for the preparation of N-substituted 1 ...