摘要:
A simple procedure for preparing fluoroethyl-N-desmethyl-loperamide 4 and its analogue 5 was developed. Standard compound 4 was synthesized in useful yields for radiolabeling analysis. [N-Ethyl-18F]N-desmethyl-loperamide, 3, was rapidly and efficiently labeled with no-carrier added fluorine-18 (t(1/2) = 109.7 min) by treatment of readily prepared [F-18]1-bromo-2-fluoro ethane with a N-desmethyl-loperamide precursor at a consistent 7% radiochemical yield. This procedure was also adapted to the radiosynthesis of 3 by [F-18]ethylene tosylate, but at a lower 3% radiochemical yield. (C) 2013 Elsevier Ltd. All rights reserved.