Radiosynthesis of a potent endothelin receptor antagonist: [C-11] L-753,037

[C-11]-L-753,037, [(+)-(5S,6R,7R)-2-butyl-7-[2-((2S)-2-carboxypropyl)- 4-[C -11]-methoxyphenyl]-5-(3,4-methylenedioxyphenyl)-cylcopenteno- [1,2-b]pyrid ine-6-carboxylate], a potent mixed antagonist of endothelin receptor subtyp es ETA and ETB, was synthesized by [C-11]-methylation of a phenolic precurs or. The time for synthesis, purification, and formulation was 17 minutes wi th an average specific radioactivity of 2535 mCi/mu mol (EOS) and average d ecay corrected radiochemical yield of 3% based on [C-11]-methyl iodide.