(6e)-6-[5-methyl-2-[4-[[(6e)-5-methyl-6-(6-oxocyclohexa-2,4-dien-1-ylidene)-1h-pyrimidin-2-yl]amino]butylamino]-1h-pyrimidin-6-ylidene]cyclohexa-2,4-dien-1-one