title: The structure of phenindamine base and salts in the solute state.
abstract: High-field NMR (13C and 1H) studies of phenindamine are reported which establish structures of the free base and some of its salts in the solute condition. The base exists as a mixture of two isomers which differ in double bond position (9-9a or 4a-9a) while most salts are 9-9a isomers. The clinically employed tartrate (Thephorin) is exceptional in being a 4a-9a ene. Salts of both double bond type exist in solution as mixtures of protonated epimers of variable epimeric ratio, that of the tartrate in D2O being approximately 1:1.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011725:Pyridines; C005430:phenindamine