1-alkyl or 1-cycloalkyltriazolo[4,3-a]quinazolin-5-ones as phosphodiesterase inhibitors

A compound of formula (I),

• in which
• R1 is:
• hydroxyl, halogen, nitro, mercapto, cyano or carboxyl,
• lower alkyl or lower alkoxy, these groups being optionally substituted with 1,2 or 3 halogen atoms, or
• —NR4R5 in which R4 and R5 are the same or different and are:
• H,
• lower alkyl, optionally substituted with 1,2 or 3 halogen, hydroxyl, cyano and lower alkoxy, or
• C(═O)R6 in which R6 is selected from:
• lower alkyl optionally substituted with OR7, or SR7 and
• —X1-cycloalkyl optionally substituted with OR7, SR7, NR7R8 or with a linear or branched C1-C4 alkyl,
• in which R7 and R8 are the same or different and are hydrogen or lower alkyl and X1 is a single bond or a linear or branched C1-C4 alkylene;
• R2 is:
• lower alkyl optionally substituted with OR9, SR9, or
• —X2-cycloalkyl optionally substituted with OR9, SR9, NR9R10 or with a linear or branched C1-C4 alkyl,
• in which R9 and R10 are the same or different and are hydrogen or lower alkyl and X2 is a single bond or a linear or branched C1-C4 alkylene;
• and
• R3 is:
• in which:
• n is an integer from 1 to 4,
• Ar is an aromatic ring comprising 5 or 6 atoms comprising zero to three O, S or N, and
• Y1, Y2 and Y3, which may be identical or different, are:
• hydrogen, hydroxyl, halogen, mercapto, nitro, C(=O)R11, C(=O)OR11, C(═O)NR12R13, NR12R13 or —(CH2)SCN in which s is an integer from 0 to 2;
• R11, R12 and R13 are each independently hydrogen or lower alkyl,
• lower alkyl or lower alkoxy, each optionally substituted with 1, 2 or 3 halogen atoms, or
• —S(O)mR14 in which m is 0 or 1 and R14 is lower alkyl, an isomer thereof or a pharmaceutically acceptable salt thereof.