2-methylsulfanyl-7-(1,2,3,4-tetrahydroxybutyl)-1H-pteridin-4-one 2-(methylthio)-7-(1,2,3,4-tetrahydroxybutyl)-1H-pteridin-4-one NCI60_015673 1-(4-Hydroxy-2-(methylthio)-7-pteridinyl)-1,2,3,4-butanetetrol AIDS-138603 AIDS138603 NSC645748