4H-Pyran-2-carboxylic acid, 5-hydroxy-6(4-methyl-1-piperazinyl)-4-oxo-, monohydrochloride 5-Hydroxy-6-(4-methyl-1-piperazinyl)-4-oxo-4H-pyran-2-carboxylic acid hydrochloride 6-(N-Methylpiperazino)comenic acid hydrochloride 86525-23-7