Several 5-substituted hydantoins display a wide range of biological properties, 1 and have proved to be useful precursors of α-amino acids after alkaline hydrolytic degradation 2 or enzymatic reactions. 3 Different approaches have been used for the construction of pyridine (or diazepine) moieties. 5-Substituted hydantoins have been found to be valuable precursors of a great variety of heterocyclic systems: 5-methoxy-3-phenylhydantoin reacts with various ...