119-44-8 2-Amino-4,6-dihydroxypteridine 2-Amino-4,6-dihydroxypyrimido[4,5-b]pyrazine 4,6-Pteridinediol, 2-amino- 4,6-Pteridinedione, 2-amino-1,5-dihydro- Ksantopterin NSC91557 Xanthopterin