Synthesis and preliminary binding studies of 4,4-ditritio-(-)-nicotine of high specific activity

4,4-Ditritio-(-)-nicotine (5) of high specific activity (4.7 Ci/mmol) has been synthesized from (-)-nicotine via the readily prepared 4,4-dibromocotinine (3). Scatchard analysis of the binding of 5 to the crude mitochondrial fraction of whole rat brain revealed a Ka of 4.7 X 10(6) M-1 and 13 fmol of binding sites/mg of protein.