Abstract:

Five precursors, N-(tert-butoxycarbonyl)-O-(2-mosyloxyethyl/nosyloxyethyl)-L-tyrosine methyl ester(9a, 11a) and N-(tert-butoxycarbonyl)-O-(2-mosyloxyethyl/tosyloxyethyl/nosyloxyethyl)-L-tyrosine-tert-butyl ester(9b，10b，11b), were designed and synthesized for O-(2-[18F]fluoroethyl)-L-tyrosine([18F]FET) used in positron emission tomography(PET) for tumor imaging. These compounds were prepared by the esterification of methanol or transesterification of tert-butyl acetate with L-tyrosine, protection of the amine group with di-tert-butyl dicarbonate, and then nucleophilic substitution with glycol sulfonate in three steps with overall yields varied from 30% to 67%.

Key words: Positron Emission Tomography, L-Tyrosine, O-(2-[18F]fluoroethyl)-L-tyrosine precursor, PET imaging