Imatinib bis Impurity

: Des(methylpiperazinyl-N-methyl) Imatinib Dimer Impurity; 1,4-bis-[4-[4-Methyl-3-[[4-(pyridin-3-yl)pyrimidin-2- yl]amino]phenyl] carbamoyl] benzyl piperazine; {3-[4-(3-Pyridyl)-2-pyrimidinylamino]toluidino}{p-[(4-{[p-({3-[4-(3-pyridyl)-2-pyrimidinylamino]toluidino}carbonyl)phenyl]methyl}-1-piperazinyl)methyl]phenyl}formaldehyde