Synthesis of saturated fatty acids 11C (13C)-labelled in the ω-methyl position

Article abstract of DOI:10.1002/(SICI)1099-1344(199706)39:6<509::AID-JLCR996>3.0.CO;2-H

A method for the preparation of saturated fatty acids ¹¹C (¹³C)-labelled in the ω-methyl position is described. A highly reactive zerovalent copper complex was prepared from lithium naphtalenide reduced lithium(2-thienyl)iodocuprate. The labelling precursors were obtained by addition of tert-butyl ω-iodocarboxylates to the organocuprate and these were reacted with [¹¹C]methyl iodide to form ¹¹C-labelled, protected intermediates. The tert-butyl ester protecting group was rapidly removed with trifluoroacetic acid, affording fatty acids ¹¹C-labelled in the ω-methyl position. A solid phase extraction method was developed and preceded final HPLC purification. In a typical run starting with 2.75 GBq of [¹¹C]methyl iodide, 375 MBq (66%) [16-¹¹C]palmitic acid was obtained within 46 min from the end of radionuclide production.