-Secretase inhibitors

A β secretase inhibitor comprising a compound represented by the formula:

• 42
• wherein Ar represents an aromatic group which may be substituted;
• X represents a divalent group selected from —O—, —S—, —CO—, —SO—, —SO2—, —NR8—, —CONR8—, —SO2NR8— and —COO— (R8 represents hydrogen atom, a hydrocarbon group or acyl which may be substituted), a divalent C1-6 aliphatic hydrocarbon group which may contain one or two of these divalent groups, or a bond;
• Y represents a divalent group selected from —O—, —S—, —CO—, —SO—, —SO2—, —NR8—, —CONR8—, —SO2NR8— and —COO— (R8 represents hydrogen atom, a hydrocarbon group or acyl which may be substituted) or a divalent C1-6 aliphatic hydrocarbon group which may contain one or two of these divalent groups;
• R1 and R2 represent hydrogen atom or a hydrocarbon group which may be substituted, respectively, or R1 and R2 may, together with the adjacent nitrogen atom, form a nitrogen-containing heterocyclic ring which may be substituted;
• and ring A represents a ring which may further be substituted, or a salt thereof.