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3월 19일(목) 외부초청세미나 : 연사 - 지대윤 교수 (서강대 화학과) |
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- 제 목 : Fluination f Molecular Imaging
- 연사 및 소속 : 지대윤 교수 (서강대 화학과)
- 일시 및 장소 : 2009년 3월 19일(목) 오후 5시, 종합과학관 B동 153호
- 초청자 : 이상기 교수
- 내 용 : Noninvasive imaging of molecular biological processes in living subjects with positron emission tomography (PET) provides exciting opptunities to monit metabolism detect diseases in humans in small-animal models. Measuring these processes with PET requires the preparation of specific molecular imaging probes labeled with positron-emitting radioisotopes. In this regard, fluine is particularly useful: (a) Because fluine can replace hydrogen with minimal steric interference, labeling pharmaceuticals with [18F]fluine often enables the fluine-substituted analog to be used to trace biochemical processes while maintaining favable interaction with the target (b) fluine is also often used as a substituent in pharmaceuticals because it can increase the activity, potency stability of biologically active compounds (c) Finally, because of its relatively long half life of 110 min, [18F]labeled radiopharmaceuticals can be produced regionally shipped f imaging studies to nearby hospitals labaties that are not equipped with particle accelerats f radionuclide production.
The typical method f introducing fluine at a specific aliphatic molecular site is the nucleophilic displacement of the cresponding sulfonate halide by fluide ion. Aprotic solvents are usually preferred f the SN2 reactions, because nucleophilicity hence SN2 reactivity are severely retarded by the influence of the partial positive charge of protic solvents. Recently, we have developed a remarkable effect of using tertiary alcohols as a reaction medium f nucleophilic fluination with alkali metal fluides. The great efficacy of this method is a particular advantage in labeling radiopharmaceuticals with [18F]fluine in high yield purity, in shter times compared to conventional syntheses. To elucidate the mechanism of this highly efficient fluination reaction process, we have carried out a series of quantum chemical calculations. In this new mechanism, the bulky, polarizable cation separates F-from the protic solvent, which in turn acts as a base to reduce the unfavable influence of the cation on the nucleophilicity of F-. We will use the term "flexible"fluide to denote the unusual behavi of fluide ion under these conditions.
Using this new fluination method, the development of several new radiopharmaceuticals such as [18F]FLT, [18F]FP-CIT, [18F]FES, [18F]FMISO will be discussed. F your infmation, [18F]FLT [18F]FP-CIT are commercially used f patients at Kea after getting the official permission from Kean FDA in this spring.
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