4-phenylamine-quinazolin-6-il-amidas.

A compound of the formula in which: R3 is linear or branched C1-C3 alkyl, optionally substituted with one or more halogens; R5 and R6 are independently selected from H, C1-C3 alkyl, F, Br, I or Cl; X is O, S or NH; and each of the dashed lines designated as a and b indicates an optional double bond, with the proviso that in a compound there is only a single double bond a or b; or a pharmaceutically acceptable salt thereof.