β-Configured clickable [18F]FDGs as novel 18F-fluoroglycosylation tools for PETElectronic supplementary information (ESI) available. See DOI: 10.1039/c7nj00716g

In oncology and neurology the 18 F-radiolabeled glucose analogue 2-deoxy-2-[ 18 F]fluoro- d -glucose ([ 18 F]FDG) is by far the most commonly employed metabolic imaging agent for positron emission tomography (PET). Herein, we report a novel synthetic route to β-configured mannopyranoside precursors and a chemoselective 18 F-fluoroglycosylation method that employ two β-configured [ 18 F]FDG derivatives equipped with either a terminal azide or alkyne aglycon respectively, for use as a CuAAC clickable tool set for PET. The β-configured precursors provided the corresponding [ 18 F]FDGs in a radiochemical yield of 77-88%. Further, the clickability of these [ 18 F]FDGs was investigated by click coupling to the suitably functionalized Fmoc-protected amino acids, Fmoc- N -(propargyl)-glycine and Fmoc-3-azido- l -alanine, which provided the 18 F-fluoroglycosylated amino acid conjugates in radiochemical yields of 75-83%. The 18 F-fluoroglycosylated amino acids presented herein constitute a new and interesting class of metabolic PET radiotracers. We have developed a chemoselective 18 F-fluoroglycosylation method for PET imaging that employ β-configured [ 18 F]FDGs as prosthetic groups for 18 F-labeling using CuAAC click chemistry.