drosopterin

A pteridine, 3,10-diamino-14-methyl-5,6,6a,6b,7,9-hexahydro-4h-pyrimido[4,5:2',3'][1,4]diazepino[6',5':3,4]pyrrolo[1,2-f]pteridine-1,12-dione, that is a red eye pigment of Drosophila melanogaster; any of a class of related compounds.