2,2'-((2-Methyl-1,4-piperazinediyl)bis(methylene(2-oxo-1H-indol-1-yl-3(2H)-ylidene)))bis(hydrazinecarbothioamide) 40262-45-1 N,N'-Bis(methylisatin-beta-thiosemicarbazone)-2-methylpiperazine Tski VI Tski-VI Tskivi