| abstract |
The present invention discloses a series of derivatives of 6,7-dihydro-3H-oxazolo [3,4-a] pyrazine-5,8-dione, mixtures thereof, and pharmaceutically acceptable salts thereof, Lt; RTI ID = 0.0 > PDE-5 < / RTI > Particularly, in particular, (R) -3- (1,3-benzodioxol-5-yl) -1- (1H-indol-3-yl) -7-methyl-6,7-dihydro [1,3 ] Oxazolo [3,4-a] pyrazine-5,8-dione derivative, its isomer, (S) -3- (1,3-benzodioxol- -Yl) -7-methyl-6,7-dihydro [1,3] oxazolo [3,4-a] pyrazine-5,8-dione. The present invention further relates to processes for the preparation of said compounds, to pharmaceutical compositions comprising said substances, as well as to the use of the enzyme phosphodiesterase type 5 (PDE-5) in the treatment of disorders treatable with erectile dysfunction and PDE- ≪ / RTI > |