Preferred substituents for the 3-position in phenyl and naphth-1-yl rings include: halogen, especially fluoro and chloro; --OR3, especially C1-4 alkoxy; CF3, NR10 R20, such as amino; NR10 C(Z)R3, especially --NHCO(C1-10 alkyl); --NR10 S(O)m 'R8, especially NHSO2 (C1-10 alkyl), and --SR3 and --SOR3 wherein R3 is preferably a C1-2 alkyl, more preferably methyl.