Stereoselective reduction via lithium borotritide: Synthesis of H-3-labeled 2-hydroxy-N-[(5-hydroxy-[5-H-3]-1,3,3-trimethylcyclohexyl)methyl]-5-methylbenzamide

H-3-labeled 2-hydroxy-N-[(5-hydroxy-[5-H-3]-1,3,3-trimethylcyclohexyl)methy l]-5-methylbenzamide, 1, was prepared in one step by the reduction of the c orresponding ketone with high specific activity LiBT4. The reduction was st ereoselective yielding the desired cis alcohol in a ratio of >20:1. Purific ation of the compound was achieved on normal-phase HPLC. The radiochemical purity of the final product was greater than 99.5% and the specific activit y was 29 Ci/mmol.