N-substituted-2-amino-4-phenyl-4-oxo-butanoic acid compounds having kynurenine-3-hydroxy base inhibitory activity

A compound of the formula (Ia)

• wherein
• each of the groups X and Y is, independently, hydrogen;
• halogen;
• nitro;
• C1-C6 alkyl;
• C2-C4 alkenyl;
• C2-C4 alkynyl;
• C1-C6 alkoxy;
• C1-C6 alkylthio;
• SOR2 or SO2R2 in which R2 is C1-C6 alkyl, phenyl or benzyl;
• or SO2N(R3)2 in which each of the groups R3 is, independently, hydrogen, C1-C6 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl or benzyl;
• R is hydroxy;
• —OR5 in which R5 is C1-C6 alkyl, C2-C4 alkenyl, C2-C4 alkynyl or benzyl;
• —N(R3)2 or —N(R3)OR3 in which each of R3 is as defined above;
• W is —SO2R4 in which R4 is C1-C6 alkyl, an optionally substituted C2-C4 alkenyl, an optionally substituted phenyl or benzyl;
• —CONHR5 or —CSNHR5 in which R5 is as defined above;
• or a pharmaceutically acceptable salt thereof.