Synthesis Of The Antiinflammatory Prodrug Rs-42169-C-14

A facile synthesis of the antiinflammatory agent RS-42169-C-14, based on a carbonation/cycloaddition sequence is described. The product was obtained in 36% yield from (BaCO3)-C-14 at a specific activity of 52 mCi/mmole. The design of the six step sequence was such that pure intermediates were isolated by extractive workup, and only a single chromatographic purification was required.