Compounds of formula (I):
[in which: X is a group of formula >CR
1
R
2
or >SO
2
; Y is a group of formula >NH or >CR
1
R
2
; Z is a group of formula >C═O or >CH
2
or a direct bond; R
1
is hydrogen and R
2
is hydrogen, carboxy or hydroxy; or R
1
and R
2
together represent an oxo group, a methylenedioxy group or a hydroxyimino group; R
3
is hydrogen or lower alkyl; R
4
represents two hydrogen atoms, or an oxo or hydroxyimino group; R
5
is hydrogen, lower alkyl or halogen; R
6
is hydrogen, lower alkoxy or carboxy; R
7
and R
8
are each hydrogen, lower alkyl or halogen; and pharmaceutically acceptable salts and esters thereof can be used for the treatment or prophylaxis of acute or chronic neurodegenerative diseases or conditions such as Alzheimer's Disease, Parkinson's Disease, Huntington's Chorea, Multiple Sclerosis or the sequelae to acute ischaemic events such as heart attack, stroke or head injury and for protection against ischaemic damage to tissues of peripheral organs.
Compounds of formula (I):
[in which: X is a group of formula >CR
1
R
2
or >SO
2
; Y is a group of formula >NH or >CR
1
R
2
; Z is a group of formula >C═O or >CH
2
or a direct bond; R
1
is hydrogen and R
2
is hydrogen, carboxy or hydroxy; or R
1
and R
2
together represent an oxo group, a methylenedioxy group or a hydroxyimino group; R
3
is hydrogen or lower alkyl; R
4
represents two hydrogen atoms, or an oxo or hydroxyimino group; R
5
is hydrogen, lower alkyl or halogen; R
6
is hydrogen, lower alkoxy or carboxy; R
7
and R
8
are each hydrogen, lower alkyl or halogen; and pharmaceutically acceptable salts and esters thereof can be used for the treatment or prophylaxis of acute or chronic neurodegenerative diseases or conditions such as Alzheimer's Disease, Parkinson's Disease, Huntington's Chorea, Multiple Sclerosis or the sequelae to acute ischaemic events such as heart attack, stroke or head injury and for protection against ischaemic damage to tissues of peripheral organs.