Facile syntheses of isotope-labeled chiral octahydroindole-2-carboxylic acid and its N-methyl analog

We have synthesized deuterium and carbon-14 labeled enantiomerically pure octahydroindole-2-carboxylic acid (PD0140417), N-methyl octahydroindole-2-carboxylic acid (PD0348183) and their racemic analogs (PD0108405 and PD0338055). [ring-U-C-14]PD0140417 was prepared from [ring-U-C-14] benzoic acid in a seven-step synthesis in 6.2% overall radiochemical yield. [C-14]PD0348183 was prepared from [C-14]BaCO3 in a five-step synthesis in 16% radiochemical yield. Additionally, [D]PD0108405 and [D]PD0338055 were synthesized by direct platinum-catalyzed hydrogenation with deuterium gas.