Neuroprotective agents

The use of substantially pure compound having the general formula (I)

• 27
• wherein:
• Q represents an amidino group, a cyano group or a group of formula XYN—, where
• X and Y are the same or different, and each may represent a hydrogen atom, a lower alkyl group, or a simple hetero-atom containing group or, together with the nitrogen atom to which they are attached, form a nitrogen-containing heterocyclic group;
• Ra represents a straight or branched chain alkylene or alkenylene group having from 1 to 6 carbon atoms and each optionally being substituted by from 1 to 4 alkyl groups each having from 1 to 3 carbon atoms;
• Rb and Rc represent an alkylene or alkenylene group having 3 or 4 carbon atoms in a straight chain, each being optionally substituted by 1 or 2 alkyl groups each having from 1 to 3 carbon atoms, the total number of carbon atoms in said straight chains of Rb and Rc being 7;
• R2 and R3 are the same as or different from each other and each represents a hydrogen atom, or a group of formula R, RCO—, ROCO—, or RNHCO—, where
• R represents a lower alkyl group or an aryl group, said alkyl or aryl group being optionally substituted by one or more of the substituents α, defined below;
• the chiral carbon atom indicated by the asterisk is in the L configuration;
• Z is an aromatic amino acid residue;
• n is 0 or 1;
• R1 represents a hydrogen atom or a lower alkyl group or an aryl group, said alkyl or aryl group being optionally substituted by one or more of the substituents α, defined below;
• 0 represents a hydrogen atom or an alkyl or aryl group;
• and
• substituents α are selected from:
• halogen atoms, amino groups, alkylamino groups, dialkylamino groups, cyano groups, hydroxy groups, alkyl groups (except when the substituted group is alkyl), aryl groups, carbamoyl groups, alkylcarbamoyl groups, dialkylcarbamoyl groups and carboxy groups and esters thereof;
• and pharmaceutically acceptable salts thereof,
• for the manufacture of a medicament for treating a mammal to protect said mammal from the neuronal damage caused by an ischaemic event.

A substantially pure compound having the formula (Ib):

• 38
• wherein:
• X and Y are the same or different, and each may represent a hydrogen atom, a lower alkyl group, or a simple hetero-atom containing group or, together with the nitrogen atom to which they are attached, form a nitrogen-containing heterocyclic group;
• Z is an aromatic amino acid residue;
• n is 0 or 1;
• R1 represents a hydrogen atom or a lower alkyl group or an aryl group, said alkyl or aryl group being optionally substituted by one or more of the substituents α, defined below;
• substituents α are selected from:
• halogen atoms, amino groups, alkylamino groups, dialkylamino groups, cyano groups, hydroxy groups, alkyl groups (except when the substituted group is akyl), aryl groups, carbamoyl groups, alkylcarbamoyl groups, dialkylcarbamoyl groups and carboxy groups and esters thereof;
• x is an integer from 1 to 5;
• y is 3 or 4;
• R4, R5, R6 and R7 may be the same or different and each represents a hydrogen atom or a lower alkyl group;
• and
• the chiral carbon atom indicated by the asterisk is in the L configuration,
• and pharmaceutically acceptable salts thereof.