Crystal and molecular structures of pyridazinone cardiovascular agents.

The crystal and molecular structures of 11 6-substituted pyridazinone derivatives: 6-phenyl-3(2H)-pyridazinone-acetic acid (1/1) (1), 6-(4-aminophenyl)- 3(2H)-pyridazinone (2), 6-(4-aminophenyl)- 5-methyl-3(2H)-pyridazinone (3), 6-(4-acetamidophenyl)- 3(2H)-pyridazinone (4), 6-(4-acetamido-2- methoxyphenyl)-3(2H)-pyridazinone (5), 6-(2-aminophenyl)-3(2H)- pyridazinone (6), 6-phenyl-3(2H)- pyrazinone (7), 6-(4-aminophenyl)-4,5-dihydro- 3(2H)-pyridazinone (8), (R)-(-)-6[4-(3-bromopropionamido)phenyl]- 4,5-dihydro-5-methyl-3(2H)-pyridazinone (9), (R)-(-)-6-(4-ammoniophenyl)-4,5- dihydro-5-methyl-3(2H)-pyridazinone (-)-tartrate-dichloromethane-methanol (1/1/1) (10), 4,5-dihydro-6-methyl-3(2H)-pyridazinone (11) have been determined as part of a study to determine the relationship between their cardiovascular properties and molecular structure and dimensions. For the two optically resolved chiral derivatives (9) and (10) the absolute configuration has been determined.