| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical resolution method of racemic 6-(4-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone, and a novel crystalline polymorphic form of substantially optically pure (-)-ä[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)phenyl]hydrazono}propanedinitrile. SOLUTION: The optical resolution method of racemic 6-(4-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone includes (a) a process for bringing the racemic mixture into contact with D- or L-tartaric acid in an ethyl acetate solvent and (b) a process for recovering a crystalline salt and (c) a process for forming a free base by bringing the salt to be the base. The crystalline polymorphic form I of substantially optically pure (-)-ä[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)phenyl]hydrazono}propanedinitrile is characterized by the X-ray diffraction pattern having specific peak positions. COPYRIGHT: (C)2008,JPO&INPIT
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