Synthesis of Selenium-75 Labeled Tertiary Diamines: New Brain Imaging Agents

Article abstract of DOI:10.1021/jm00184a012

Selenium-75 labeled tertiary diamines, bis<β-(N,N-dimethylamino)ethyl> selenide (1), bis<β-(N,N-diisopropylamino)ethyl> selenide (2), bis(β-piperidinoethyl) selenide (3), and bis(β-morpholinoethyl) selenide (4), were prepared by reducing <75Se>selenious acid with sodium borohydride and reacting the intermediate with N,N-disubstituted aminoethyl chlorides.The effect of pH on lipid solubility (1-octanol/buffer distribution coefficient) was measured for each labeled compound.Biodistribution studies in rats showed high brain uptake for the tertiary diamines, especially for 3 and 4 (1.53 and 1.49percent dose/organ, respectively, at 30 min after iv injection).The permanently charged bisquaternary amine, bis<β-(N,N,N-trimethylammonio)ethyl> selenide (5), showed negligible brain uptake (0.06percent dose/organ at 30 min).