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[18F]FPyKYNE‐c(RGDyK) was successfully synthesized by the Cu(I) catalyzed Huisgen 1,3‐dipolar cycloaddition of alkynes to azides using [18F]FPyKYNE as a prosthetic group in an overall radiochemical yield of 12%–18% (decay‐corrected) and >99.5% chemical and radiochemical purities in 125 min including quality control. This simple, fully automated two‐step, two‐reactor approach consists of a quick and convenient purification of the prosthetic group using silica gel cartridges and its subsequent use for the labeling of the azido‐c(RGDyK) peptide via click chemistry.

The high affinity and selective cAMP-specific phosphodiesterase-4 inhibitors Ro 20-1724, R-, R/S- and S-rolipram were labeled with ¹¹C by O-[¹¹C]methylation of their respective phenolic precursors using [¹¹C]methyl iodide. The desmethyl precursor of Ro 20-1724 was prepared by selective dealkylation with iodotrimethylsilane, whereas, dealkylation of racemic rolipram was not selective and yielded several products. Enantiomeric separation of R- and S-desmethylrolipram was carried out by chiral semi-preparative high performance liquid chromatography. The final ¹¹C-labeled products were prepared in high radiochemical purity (>99%), yields (45-75%, decay-corrected) and specific activities [18.5-92.5 GBq/µmol], within 30 min from end-of-bombardment. Copyright © 2001 John Wiley & Sons, Ltd.

With the aim to establish the labeling position in the radiosynthesis of the dopamine D1 agonist R-[^11/13C]SKF 82957, reaction mixtures containing R-SKF 81297, N-ethyldiisopropylamine, and [¹³C]methyl oidide or [¹³C]methyl triflate, were analyzed using ¹H- and ¹³C-NMR, as well as 2D ¹H-¹³C-NMR. Only R-[N-methyl-¹³C]SKF 82957 was obtained using sub-molar quantities of [¹³C]methyl iodide. In contrast, a second ¹³C-labeled peak, likely corresponding to an O-[¹³C]methylated derivative, was observed with the highly reactive [¹³C]methyl triflate. Similar results were obtained in the synthesis of the structurally similar R-[¹³C]SCH 23390. Copyright © 2000 John Wiley & Sons, Ltd.