Synthesis of 4‐[2‐(4‐Azidophenyl)‐5‐(3‐iodo‐125I‐phenyl)‐1H‐imidazol‐4‐yl]pyridine (SB 206718‐[125I]), a pyridinyl imidazole cytokine inhibitor

The pyridinyl imidazole cytokine-suppressing anti-inflammatory drug (CSAID), SB 206718 (1) was required in 125 I-labeled form for photoaffinity ligand studies. The target compound (SB 206718-[ 125 I], [ 125 I]1) was obtained via conversion of the highly functionalized 1 to a tributylstannyl derivative. Radioiododestannylation using Na 125 I in the presence of chloramine-T gave good radiochemical yields of the title compound (42-69%, four radiosyntheses) at high radiochemical purity (>98%) after HPLC purification at specific activities of 1670-1736 Ci/mmol.