METHOD FOR OBTAINING PURE ENANTIOMERS OF A PYRIDAZINONE DERIVATIVE

摘要

A method for preparing optically substantially pure (-)-[[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)phenyl]hydrazono]propanedinitrile from racemic 6-(4-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone intermediate is described. The end product is useful as a cardiotonic agent. A novel crystalline polymorphic form of the end product is also described.