Compositions for treatment of cancer

A pharmaceutical composition comprising as an active ingredient a compound of formula (1)

• R1 and R4 are non-interfering substituents independently selected from the group consisting of halo, nitro, OR2, OCOR2, COOR2, R2NCOR2, CONR22, COR2, NR22, S(0)mR2, —CN and R3,
• where each R2 is independently H or alkyl (1-4)
• R3 is alkyl (1-6) or substituted alkyl (1-6) wherein the substituents are halo, OR2 or NR22,
• n is 0, 1 or 2,
• m is 0, 1 or 2,
• p is 0 or 1,
• each X1-X4 is independently N or CR2, wherein at least one of X1-X4 is N,
• Y is O or S or NH, and
• Z is OR2, NR22 or S(O)mR2,
• or the pharmaceutically acceptable salts thereof.