Synthesis of N-Pyridines and Higher Mass Isotopologs via Zincke Imine Intermediates.

Methods to incorporate stable radioisotopes are integral to pharmaceutical and agrochemical development. However, despite the prevalence of pyridines in candidate compounds, methods to incorporate N atoms within their structures are limited. Here, we present a general approach to pyridine N-labeling that proceeds via ring-opening to Tf-Zincke imines and then ring-closure with commercially available NHCl salts.