The invention provides novel 7,8-dihydro-imidazo[l,2-α]pyrazolo[4,3-e]pyrimidin-4- one compounds and 7,8,9-trihydro-[lHor 2/f]-pyrimido [l,2-a]pyrazolo[4,3- e]pyrimidin-4(5H)-one compounds, substituted at the 1 or 2 position with C2-g allcyl, C3-9 cycloalkyl, heteroarylalkyl, or substituted arylalkyl, in free, salt or prodrug form, processes for their production, their use as pharmaceuticals, particularly as PDEl inhibitors, and pharmaceutical compositions comprising them.
