Syntheses of Iron Bis(pyridoxal isonicotinoylhydrazone)s and the in Vivo Iron-Removal Properties of Some Pyridoxal Derivatives

Pyridoxal isonicotinoylhydrazone (PINH; 1) and its isomeric O-acetates (E and Z) were synthesized and complexed with ferrous ions to afford the hitherto unisolated chelates iron(II) bis(pyridoxal isonicotinoylhydrazone)s (11) and iron(II) bis(O-acetylpyridoxal isonicotinoylhydrazone)s (12). The analytical and spectroscopic data of the new coordination compounds are presented. In addition, a series of imino derivatives of pyridoxal of structures 2-3 and 5-10 have been prepared and tested in vivo as chelators of storage iron, and the cumulative net excretion of radioiron in urine and in feces was estimated. This study reestablishes that PINH is a potent iron chelator in vivo comparable in efficiency with parenteral desferrioxamine (DF) and indicates that it requires further attention.