Radiosynthesis of O‐[¹¹C]methyl‐L‐tyrosine and O‐[¹⁸F]Fluoromethyl‐L‐tyrosine as potential PET tracers for imaging amino acid transport

Abstract

Summary Two positron-emitting analogues of tyrosine, O-[11 C]methyl-l-tyrosine and O- bubbled through a dimethylsulfoxide solution of l-tyrosine disodium salt at room temperature. After subsequent HPLC purification the labeled l-tyrosine analogues were obtained in decay-corrected radiochemical yields of over 50%, based on their corresponding labeling agent, with radiochemical purities always higher than 98%. The quite straightforward preparation, together with the high radiochemical yields achieved, make both these syntheses suitable for routine production.

Improved synthesis of [18F]fluoromethyl tosylate, a convenient reagent for radiofluoromethylations

“…The preparation of [ 18 F]fluoromethyl triflate (3, X ¼ OTf) has recently been reported. 12,13 Although this precursor is highly reactive, its preparation involves two steps and requires a specialized synthesis system. It was hoped some of the disadvantages of these labeling reagents could be circumvented.…”

“…[14][15][16] Reaction of Based upon their observations, some modifications were made to determine the affect on yield. In the present work, the reaction was carried out in acetonitrile, dimethylformamide and acetone, using 18 13,20 based upon analysis by TLC and HPLC. 18 The reaction of bis(tosyloxy) methane with unlabeled KF produced fluoromethyl tosylate 14,15 21,22 The product of a separate reaction of tosyl chloride with high specific activity 18 F-also coeluted on TLC and HPLC with the reaction byproduct.…”

Synthesis and Characterization of 18F-Interleukin-8 Using a Cell-Free Translation System and 4-18F-Fluoro-l-Proline

“…Initially we unsuccessfully screened unlabeled fluorinated amino acids such as O-fluoromethyl-L-tyrosine, which have been used for radiolabeling (13,20), to be directly incorporated into proteins in a cell-free translation system derived from E. coli. instead of natural amino acids without any additional components.…”

“…O-fluoroethyl-L-tyrosine was purchased from ABX GmbH. O-fluoromethyl-L-tyrosine was synthesized as previously described (13).…”

[18F]Fluoromethyl iodide ([18F]FCH2I): preparation and reactions with phenol, thiophenol, amide and amine functional groups

“…On the other hand, in the flurine-18 ( 18 F) chemistry, [ 18 F]fluoromethylation of nucleophilic substrates has become an effective approach for developing a positron emission tomography (PET) ligand [6][7][8][9][10][11]. Since [ 18 F]fluoromethyl group displays similar electronic and steric properties with [ 11 C]methyl group, the [ 18 F]fluoromethylated ligands [12,13] [3].…”