prov:value
| - X, Y or Z is ???N???, or W and Z are ???N???; R1, R2, R3 and R4 are independently hydrogen, halo (particularly chloro and fluoro), lower alkyl (particularly methyl), substituted lower alkyl, lower alkoxy (particularly methoxy), cyano or absent; more particularly three of R1, R2, R3 and R4 are hydrogen, or two of R1, R2, R3 and R4 are hydrogen and a third is halo, methoxy or cyano, and the fourth i
|