CHED 276 |
| The present work reports the first synthesis of fluorine-18 (18F, half-life = 109.7 min) labelled 1-fluoro-2-propanamine ([18F]fluoro-isopropylamine). Nucleophilic ring-opening of a benzyloxycarbonyl (CBz)-activated aziridine with fluoride was demonstrated. CBz-N-2-methylaziridine was reacted with 18F-labelled potassium cryptand fluoride for 20 min in DMSO at 75 °C to generate the ring-opened product, CBz-N-fluoroisopropylamine (40% conversion from starting [18F]-activity; n>25). Following solid-phase extraction, the CBz-group was quantitatively removed by catalytic hydrogenation with Pd-C in methanol or acetonitrile. [18F]fluoro-isopropylamine was directly used in a model reaction with benzoyl chloride to prepare the respective benzamide (67% conversion from [18F]fluoro-isopropylamine), and in an epoxide ring-opening reaction to synthesize (S)-[18F]-fluoro-Exaprolol, a novel radiopharmaceutical for imaging ß-adrenergic receptors. Both of the above-mentioned reactions are conducted in one-pot with an end of synthesis time of 2 hours (ca. 1 half-life). This 18F-analog of isopropylamine is a synthetically versatile reagent for preparing radiopharmaceuticals for medical imaging with positron emission tomography. |
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Undergraduate Research Poster Session
2:30 PM-4:30 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Chemical Education |