Hiroko Koyama

By Masaaki Suzuki, Hiroko Koyama, Misato Takashima-Hirano and Hisashi Doi

Part of the book: Positron Emission Tomography

By Masaaki Suzuki, Hiroko Koyama, Hideki Ishii, Koichi Kato, Margareta Ögren and Hisashi Doi

General synthesis of prostaglandins (PGs) has been accomplished based on a one-pot three-component coupling using a combination of organocopper or organozincate conjugate addition to 4-hydroxy-2-cyclopentenone followed by trapping of resulting enolate with an organic halide. Based on the use of this synthetic methodology, biologically significant PG derivatives including ent-Δ7-PGA1, 15SAPNIC ([3H]APNIC), and 15R–TIC have also been synthesized. Ultimately, organozincate conjugate addition combined with the enolate trapping by an organic triflate results in practical green three-component coupling comprising the use of stoichiometric amounts of three components (enone, α- and ω-side chains in a nearly 1:1:1 ratio) without using HMPA and heavy metals. General methodology for introducing short-lived 11C and 18F radionuclides into carbon frameworks has been established by developing rapid C-[11C]methylation and C-[18F]fluoromethylation using Pd0-mediated rapid cross-coupling between [11C]methyl iodide and an organotributylstannane or organoboronate; or [18F]fluoromethyl bromide and organoboronate, respectively, allowing the synthesis of a wide variety of biologically significant and disease-oriented PET probes such as 15R-[11C]TIC. Moreover, PdII-mediated rapid C-[11C]carbonylation using [11C]CO and organoboronate at ambient temperature under atmospheric pressure using conventional helium carrier gas has been explored. Further, C-[11C]carboxylation has been promoted using [11C]CO2 and organoboronate with RhI catalyst under atmospheric pressure.

Part of the book: Green Process of Three-Component Prostaglandin Synthesis and Rapid ¹¹C Labelings for Short-Lived PET Tracers