The disclosure relates to a family of 1,6-disubstituted pyrazolopyrimidinones of formula (I). Hc is a tetrahydropyranyl- group and R1 is the group V-W-*, wherein V and W may be an aryl group or a heteroaryl group and are chosen independently. These various groups may be further substituted. R2 and R3 are chosen from hydrogen, fluorine or fluorinated alkyl groups. These compounds inhibit PDE9 and pharmaceutical compositions and medicaments using these compounds are also disclosed. These compositions and medicaments may be used in the treatment of conditions concerning deficits in perception, concentration, learning or memory, including Alzheimer's disease and the cognitive impairment associated with Alzheimer's disease.
