Abstract: The present invention provides for compounds of formula (I), (Ia) and (Ib) Wherein: A is selected from C—X and N, B is selected from C—Y and N, R1 is selected from H and (C1-C6)alkyl, R2 is selected from H and (C1-C6)alkyl, X is selected from H, HO, C(O)NH2, NH2 Y is selected from H, HO, NH2, Br, Cl and F Z is selected from H, HO F, CONH2 and CN; And pharmaceutically acceptable salts, solvates and prodrugs thereof; With the provisos that: for a compound of formula (I), (Ia) or (Ib), when A is C—X, B is C—Y, R1 is H or (C1-C6)alkyl and R2 is H or (C1-C6)alkyl at least one of X, Y and Z must be OH; for a compound of formula (I), when A is C—X and B is C—Y, Y is H, Z is H, R1 is H and R2 is H, then X cannot be OH; these compounds are useful as a medicament.