3H-[1,2,5]thiadiazolo[3,4-d]pyrimidine-7-thione

7H-pyrimido[4,5-b][1,4]thiazine-4,6-diamine

[1,3]thiazolo[5,4-d]pyrimidine-2,7-diamine

N-phenyl-[1,2,5]thiadiazolo[3,4-d]pyrimidin-7-amine