Scheme 2.

Late‐stage labeling of benzoimidazolones with carbon isotopes. The position of the azide on the o‐azidoaniline precursor is highlighted in bold. [a] Yield of the isolated product. [b] Radiochemical conversion. Boc=tert‐butoxycarbonyl.

Late‐stage labeling of benzoimidazolones with carbon isotopes. The position of the azide on the o‐azidoaniline precursor is highlighted in bold. [a] Yield of the isolated product. [b] Radiochemical conversion. Boc=tert‐butoxycarbonyl.