Tricyclic Compounds And Their Use As Phosphodiesterase Inhibitors

摘要

The present invention is directed to compounds of Formula I:; ;or a pharmaceutically acceptable salt thereof, wherein the substituents A, R¹, R², R^3a, R^3b, R^4a, R^4b and n are as defined herein. The inventions also directed to pharmaceutical compositions comprising the compounds, methods of treatment using the compounds and methods of preparing the compounds.