Synthesis of 2-[18F]fluoro-2-deoxy-L-glucose and positron emission tomography studies in monkeys

2-[18F]Fluoro-2-deoxy-L-glucose was synthesized from its trifluoromethanesulfonyl precursor. The precursor was prepared by selective acetylation and triflation of L-mannose. L-Mannose was first treated with acetic anhydride in the presence of a catalytic amount of perchloric acid and then reacted with phosphorus tribromide followed by aqueous sodium acetate to produce pure 1,3,4,6-tetra-O-acetyl-a-L-mannopyranose in 32% yield. This compound was treated with trifluoromethanesulfonic anhydride and pyridine in methylene chloride to form 1,3,4,6-tetra-O-acetyl-O-tritrifluoromethanesulfonyl-a-L-mannopyra nose in 77% yield. Nucleophilic substitution of the triflate with 18F-in the presence of Kryptofix 2,2,2 followed by acid hydrolysis produced 2-[18F]fluoro-2-deoxy-L-glucose with a radiochemical yield of 20-30% (EOS) within 90 min. Biodistribution studies in rats and PET imaging in Rhesus monkeys demonstrated that this sugar analog distributes in the extracellular space of most organs but is excluded from the CNS.