SOLID-PHASE RADIOSYNTHESIS OF [C-11]WAY-100635

An efficient, fast and simple method is described for the radiosynthes is of the potent and selective 5-HT1A antagonist l)-1-piperazinyl]ethy l]-N-(2-pyridinyl)cyclohexane carboxamide ([C-11]WAY 100635). [C-11]Io domethane was effectively trapped on a C-18 reverse-phase cartridge at ambient temperature where it reacted rapidly with the normethyl precu rsor, ydroxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane c arboxamide. Following high performance liquid chromatography purificat ion and formulation, [C-11]WAY 100635 was obtained in high radiochemic al yields (40%, uncorrected from [C-11]Iiodomethane) in a synthesis ti me of 25 min with an average specific actvity of (at end-of-synthesis) 33 GBq/mu mole (900 mCi/mu mole).