Abstract: Disclosed are pteridine derivatives of formula (I): (I), wherein, for example, R1 and R2 are hydrogen, C1-C6 alkyl, carboxyl, formyl, C1-C6 hydroxyalkyl, C1-C6 carboxyalkyl, C1-C6 formyl alkyl, C1-C6 alkoxy, acyloxy, acyloxyalkyl wherein the alkyl is C1-C6, halogen, or hydroxy, or a group of formula II: (II); and R3 is (a) phenyl or (b) a cyclic group having at least one 5 or 6-membered heterocyclic ring, optionally with a carbocyclic or heterocyclic ring fused thereto, wherein each heterocyclic ring has at least one hetero atom chosen from O, N, or S; or (c) a phenyl group or a cyclic group, the cyclic group optionally with a carbocyclic or heterocyclic ring fused thereto, which is substituted with 1 to 5 substituents.