US Patent 9487527 Pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione derivatives useful as inhibitors of phosphodiesterase I

Optionally substituted (5- or 7- amino)-3,4-dihydro-(optionally 4-oxo, 4-thioxo or 4-imino)- 1H-pyrrolo [3,4-d]pyrimidin-2(6H)-ones, Compounds of Formula I, processes for their production, their use as pharmaceuticals and pharmaceutical compositions comprising them.