4-amino-2H-pyrazolo[3,4-d]pyrimidine-3-carbothioamide

3-[amino(nitroso)methylidene]-1,2-dihydropyrazolo[3,4-d]pyrimidin-4-amine

3-[amino(hydrazinyl)methylidene]pyrazolo[3,4-d]pyrimidin-4-amine