Referring to triazolopirazinonas derivative compounds of formula (i), where n is 0 OR 1 r1 is alkyl oxetanilo C1, C8, tetrahidrofuranilo, among others R2 is C1 C8 alkyl, phenyl,Among others R3 is c1-c4 alkyl, phenyl, phenyl substituted by Halogen and tetrahidrofuranilo R4 is c1-c4 alkyl, halogen and tetrahidrofuranilo.It also relates to a Pharmaceutical composition. These compounds are of PDE1 inhibitors and are useful in the treatment of neurodegenerative Disorders and Psychiatric DisordersReferida a compuestos derivados de triazolopirazinonas de formula (I), donde n es 0 o 1 R1 es alquilo C1-C8, oxetanilo, tetrahidrofuranilo, entre otros R2 es alquilo C1-C8, fenilo, entre otros R3 es alquilo C1-C4, fenilo, fenilo sustituido con halogeno y tetrahidrofuranilo R4 es alquilo C1-C4, halogeno y tetrahidrofuranilo. Tambien esta referida a una composicion farmaceutica. Dichos compuestos son inhibidores de PDE1 y son utiles en el tratamiento de trastornos neurodegenerativos y trastornos psiquiatricos
