Synthesis and HPLC‐purification of [77Br]TMC125‐R165335 (etravirine), a new anti‐HIV drug of the DAPY‐NNRTI class

[77Br]TMC125-R165335 (etravirine) was synthesized for imaging studies by SPECT. Labelling was performed with bromine-77 by electrophilic substitution of the desbromo-precursor 4-{6-amino-2-[(4-cyanophenyl)amino]pyrimidin-4-yloxy}-3,5-dimethylbenzenecarbonitrile using carrier-free 77Br− and chloramine-T (CAT) as oxidizing agent. The reaction proceeded in 10 min at room temperature in aqueous DMSO as solvent. Purification was performed by HPLC, giving a chemically and radiochemically pure [77Br]TMC125-R165335 (etravirine) in aqueous ethanol. A final radiolabelling yield of 50% is obtained. Copyright © 2006 John Wiley & Sons, Ltd.