- Convincing Catalytic Performance of Oxo-Tethered Ruthenium Complexes for Asymmetric Transfer Hydrogenation of Cyclic α-Halogenated Ketones through Dynamic Kinetic Resolution
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A highly efficient dynamic kinetic resolution of cyclic halohydrins was achieved by the asymmetric transfer hydrogenation of racemic α-haloketones. Bifunctional oxo-tethered Ru(II) catalysts could promote the reduction without deterioration of halogens. By structural tuning of the catalyst, chiral alcohols having halogen, ester, carboxamide, and sulfone functions were obtained variably with excellent diastereo- and enantioselectivities (up to >99:1 d.r. and >99.9 ee), which provided a concise synthetic approach to a dopamine D3 receptor ligand, (+)-PHNO.
- Touge, Taichiro,Nara, Hideki,Kida, Michio,Matsumura, Kazuhiko,Kayaki, Yoshihito
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p. 3070 - 3075
(2021/05/05)
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- Synthesis of the dopamine D2/D3 receptor agonist (+)-PHNO via supercritical fluid chromatography: Preliminary PET imaging study with [3-11C]-(+)PHNO
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Carbon-11 labeled (+)-4-[1-11C]propyl-3,4,4a,5,6,10b-hexahydro- 2H-naphtho[1,2-b][1,4]oxazin-9-ol ([1-11C]-(+)-PHNO) is a dopamine D3-preferring agonist radiopharmaceutical used for medical imaging by positron emission tomography (PET). We report the synthesis of (+)-PHNO using supercritical fluid chromatography for enantiomeric resolution of its norpropyl derivative, HNO, followed by propylation. (+)-HNO was used to prepare the radiolabeling precursor, (+)-trans-4-acetyl-9-triisopropylsilyloxy-2,3,4a,5,6, 10b-hexahydro-4H-naphth[1,2b][1,4]oxazine, in 12 steps. Modifications to the labeling procedure were made to ensure consistent preparation of [3- 11C]-(+)-PHNO via [11C]CH3I. A preliminary PET imaging study was carried out with this tracer in an attempt to image dopamine receptors in brown adipose tissue (brown fat) in vivo.
- Shoup, Timothy M.,McCauley, John P.,Lee Jr., David F.,Chen, Rui,Normandin, Marc D.,Bonab, Ali A.,El Fakhri, Georges,Vasdev, Neil
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p. 682 - 685
(2014/01/23)
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