SYNTHESIS, NMR CHARACTERIZATION, AND A SIMPLE APPLICATION OF LITHIUM BOROTRITIDE

LiBH4 is a powerful and selective reagent for regiospecific reduction reactions. A simple synthesis of (LiBH4)-H-3 at near theoretical speci fic radioactivity is reported. We have treated (LiH)-H-3 synthesized f rom tritium gas (H-3(2), similar to 98%) with BBr3 to produce (LiBH4)- H-3 (specific activity = 4120 GBq/mmol = 110 Ci/mmol. The maximum theo retical specific activity of (LiBH4)-H-3 is 4252 GBq/mmol = 115.04 Ci/ mmol; 1 matom of H-3 = 1063 GBq = 28.76 Ci.) The tritium labeling perf ormance of the reagent was tested by an exemplary reduction of 2-napht haldehyde to 2-naphthalenemethanol. (LiBH4)-H-3 and the reduction prod ucts were characterized by a combination of H-1, H-3, and B-11 NMR tec hniques, as appropriate.