NEW DERIVATIVES OF PIRIDAZIN-3 (2H) -ONA.

摘要

New derivatives of pyridazin-3 (2H) -one. The present invention relates to novel therapeutically useful pyridazin-3 (2H) -one derivatives of formula I, processes for their preparation and pharmaceutical compositions containing them. The values of R, R2, R3 and R4 are indicated in the description. These compounds are potent and selective inhibitors of phosphodiesterase 4 (PDE4), and are therefore useful in the treatment, prevention or suppression of pathological conditions, diseases and disorders known to be capable of being improved by PDE4 inhibition.