| 摘要 |
A series of derivatives of 6,7-dihydro-3H-oxazolo[3,4-a]pyrazine-5,8-dione, mixtures thereof, their pharmaceutically acceptable salts, which are inhibitors of PDE-5, possessing vasodilatator properties and relaxing effects. In particular, compounds of formula (I), where R1, R2, R3, and R4 are defined herein, processes for the preparation of said compounds, pharmaceutical compositions containing them, as well as uses as inhibitors of the enzyme phosphodiesterase type 5 (PDE-5) in the treatment of the erectile dysfunction and PDE-5 inhibitor treatable disorders. |
