PYRAZOLO [3,4-B] PYRIDINE COMPOUNDS, AND THEIR USE AS PHOSPHODIESTERASE INHIBITORS

摘要

The invention provides a compound of formula (I) or a salt thereof: wherein Ar has the sub-formula (x) or (z): and wherein R³ is optionally substituted C_3-8cycloalkyl, optionally substituted C_5-7cycloalkenyl, an optionally substituted heterocyclic group (aa), (bb) or (cc), or a bicyclic group (ee); and wherein R⁴ is H, C_1-3alkyl, C_1-2fluoroalkyl, cyclopropyl, -CH₂OR^4a, -CH(Me)OR^4a, or -CH₂CH₂OR^4a; and R⁵ is inter alia H, C_1-8alkyl, C_1-3fluoroalkyl, C_3-8cycloalkyl, certain substituted alkyl groups, -(CH₂)_n¹³-Het, or optionally substituted phenyl or -CH₂-Ph; or R⁴ and R⁵ taken together are -(CH₂)_p¹- or -(CH₂)_p³-X⁵-(CH₂)_p⁴-; provided that at least one of R⁴ and R⁵ is not a hydrogen atom (H). The invention also provides the use of the compounds as inhibitors of phosphodiesterase type IV (PDE4) and/or for the treatment and/or prophylaxis of inflammatory and/or allergic diseases such as chronic obstructive pulmonary disease (COPD), asthma, rheumatoid arthritis, allergic rhinitis or atopic dermatitis.