Benzofurans as suppressors of neurodegeneration

A compound of the formula:

• wherein R1 and R2 are each a C1-6 alkyl or R1 and R2 form, taken together with the adjacent carbon atom, a piperidine optionally substituted by 1 to 3 substituents selected from the group consisting of C1-6 alkyl, C6-14 aryl and C7-16 aralkyl;
• R3 is a phenyl optionally substituted by 1 to 3 substituents selected from the group consisting of halogen atoms, C1-6 alkyl, C1-6 alkoxy, amino, mono-C1-6 alkylamino and di-C1-6 alkylamino;
• R4 is
• (i) C1-6 alkyl substituted by a phenyl or pyridyl, each of which is optionally substituted by 1 to 3 substituents selected from the group consisting of halogen atoms, C1-6 alkyl, C1-6 alkoxy, hydroxy, amino, mono-C1-6 alkylamino, di-C1-6 alkylamino and carboxy, or
• (ii) an acyl of the formula:
• —(C═O)—R5′ wherein R5′ is a phenyl or phenyl-C1-6 alkyl, each of which is optionally substituted by 1 to 3 substituents selected from the group consisting of halogen atoms, C1-6 alkyl, C1-6 alkoxy, hydroxy, amino, mono-C1-6 alkylamino, di-C1-6 alkylamino and carboxy;
• X is an oxygen atom;
• Y is an oxygen atom;
• and
• ring A is a benzene ring which is optionally further substituted by 1 to 3 substituents selected from the group consisting of halogen atoms, halogenated or unhalogenated C1-6 alkyl, halogenated or unhalogenated C1-6 alkoxy, amino, mono-C1-6 alkylamino and di-C1-6 alkylamino,
• provided that when is a single bond, R4 is not acyl, and salts thereof.