Simple preparation of new [(18) F]F-labeled synthetic amino acid derivatives with two click reactions in one-pot and SPE purification.

Abstract

New [(18) F]fluorinated 1,2,3-triazolyl amino acid derivatives were efficiently prepared from Huisgen 1,3-dipolar cycloaddition reactions, well known as click reaction. We developed two simultaneous click reactions in one-pot with a simple solid-phase extraction (SPE) purification method. [(18) F]fluoro-1-propyne was obtained at a 45% non-decay corrected radiochemical yield based on the [(18) F]fluoride ion. The one-pot and simultaneous two click reactions were performed with unprotected azido-alkyl amino acid, [(18) F]fluoro-1-propyne, and lipophilic additive alkyne to produce three synthetic amino acid derivatives, AMC-101 ([(18) F]-6a), AMC-102 ([(18) F]-6b), and AMC-103 ([(18) F]-6c) with 29%, 28%, and 24% of non-decay corrected radiochemical yields, respectively. All radiotracers indicated that radiochemical purities were >95% without any residual organic solvent. Our new method involving two click reactions in one-pot showed high radiochemical and chemical purity by easy removal of the residual precursor from the simultaneous two click reactions.