Carbon‐14 labelled nitrogen heterocycles; the syntheses of three phosphodiesterase inhibitors

Abstract
The syntheses of three heterocyclic phosphodiesterase inhibitors are described from a common radiolabelled precursor, namely 2‐propoxybenzo[cyano14C]nitrile. Conversion of the nitrile to the corresponding methyl ketone or amidine allows elaboration of the heterocycles radiolabelled within the ring systems.