1-Piperazineacetic acid, 4-methyl-, (1,2-dihydro-2-oxo-3H-indol-3-ylidene)hydrazide, (E)- 1-Piperazineacetic acid, 4-methyl-, (2-oxo-3-indolinylidene)hydrazide, (E)- 4-Methyl-1-piperazineacetic acid trans-(2-oxo-3-indolinylidene)hydrazide 86873-21-4