- Photochemical Synthesis of Carbon-14 Labelled Dibenzanthracene
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Carrier-free dibenzanthracene (DBA,12*) has been prepared for the first time using methyl iodide as the source of the label.The key step in this radiosynthesis consisted of the regiospecific photocyclization of 2',5'-divinyl-1,1':4',1''-terphenyl 10* to 5,6,12,13-tetrahydro-DBA 11* followed by dehydrogenation to 12* with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone).Divinylterphenyl 10* was obtained from 2',5'-bis(bromomethyl)-1,1':4',1''-terphenyl 3 via the diformyl derivative 9 and its Wittig olefination with the triphenylphosphonium salt of14CH3I.Thus 12* was synthesized with a radiochemical purity exceeding 99percent.The chemical yield amounted to 58percent from 9 in the case of 12* with a specific activity of 391 MBq mmol-1 and to 12percent in the case of carrier-free 12* with a specific activity of 4.14 GBq mmol-1.Wide applicability of this radiosynthetic approach to the preparation of many other carbon-14 labelled polycyclic aromatic hydrocarbons can be envisaged.
- Platt, Karl L.,Setiabudi, Frans
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p. 2005 - 2010
(2007/10/02)
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