A potent inhibitor of cGMP-dependent phosphodiesterase 2A (PDE2A) with IC50 = 2 nM. It is a highly selective compound for PDE2A with > 500-fold higher affinity over other phosphodiesterases. The compound demonstrated in vivo activity as evidenced by the increase of cGMP in rodent brain. It has improved brain penetration, which makes it suitable for the treatment of neurological disorders. The compound is able to reverse anxiolytic behaviour, enhance performance of new object recognition and social recognition tasks. It potentiates NMDA signalling and reverses the behavioural effects of NMDA antagonists.