Iodoacetylated ouabagenins: their syntheses, spectroscopic characterizations, and stability studies

Ouabain shows high binding ability to myocardial Na+,K(+)-ATPase and, therefore, a suitably radiolabeled derivative of this compound may find use in myocardial imaging. In this pilot experiment we report the preparation of several chloroacetylated and iodoacetylated ouabagenins. These intermediates may possess the potential for conversion to 99mTc-labeled tracer by a reported procedure with which the imaging of myocardial Na+,K(+)-ATPase may be possible. Appropriate analytical and spectroscopic data for these intermediates are reported for the first time. To determine the stability of the iodoacetylated ouabagenins, corresponding 131I derivatives were synthesized which showed sufficient stability for incorporating a suitable radiometal-binding chelating moiety to these steroid molecules.