1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-ones and 1,5-dihydro-4H-pyrazolo[4,3-c]pyridin-4-ones as PDE1 inhibitors

A compound of formula (I):

• wherein:
• Y is N or CH;
• R1 is selected from the group consisting of linear or branched C2-C8 alkyl, saturated monocyclic C3-C8 cycloalkyl, oxetanyl, tetrahydrofuranyl and tetrathydropyranyl;
• all of which can be substituted one or more times with one or more substituents selected from the group consisting of methyl, fluorine, hydroxy, cyano and methoxy;
• R2 is:
• (a) selected from the group consisting of linear or branched C1-C8 alkyl, phenyl, benzo[1,3]dioxole and saturated monocyclic C3-C8 cycloalkyl;
• or
• (b) phenyl substituted one or more times with one or more substituents selected from the group consisting of halogen, C1-C3 alkyl and methoxy;
• or
• (c) pyridyl substituted with a substituent selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 fluoroalkoxy, C3-C4 cycloalkoxy and C4-C5 methylcycloalkoxy;
• or
• (d) selected from the group consisting of 5-membered heteroaryls substituted with C1-C3 alkyl;
• and
• R3 is selected from the group consisting of linear or branched C1-C3 alkyl and saturated monocyclic C3-C8 cycloalkyl;
• which can each be optionally substituted with a substituent selected from halogen, C1-C3 alkoxy, phenyl, dialkylamine and oxetane;
• or a tautomer or pharmaceutically acceptable salt thereof.