Piperidine and piperazine derivatives as inhibitors of the abeta fibril formation

A compound of formula I

• 12
• wherein
• X is
• 13
• wherein R′ is a group (a)
• 14
• and either R″ is H or OH and R′″ is a group (b), (c) or (d)
• 15
• or R″ and R′″ each are a group (c),
• wherein Z is H, halogen, trifluoromethyl, (C1-4)alkyl or (C1-4)alkoxy, Q° is —O—, —NH—CO— or a single bond and R° is hydrogen or hydroxy,
• Y1 and Y2 are H or, when X is
• 16
• wherein R″ is H and R′″ is a group (d), Y1 and Y2 can also form together a —CH2—CH2— bridge, and
• R is a group (e) or (f)
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• wherein
• n is 0 to 3
• R1 is H, (C1-4)alkyl or —SO2—CH3
• R2 is H, halogen, (C1-4)alkyl, (C1-4)alkoxy, (C1-4)alkylthio or phenyl,
• R3 is H, (C1-4)alkyl or a group (g)
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• wherein Z is as defined above,
• R4 and R5 each are H or together form a bond, or R4 is H and R5 is (C1-4)alkoxy,
• R6 is (C1-4) alkyl or a group (g) and
• R7 is (C1-4) alkoxy,
• provided that when X is
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• R is of formula (f) and n is 1, then Z is different from fluor in free base or acid addition salt form.