| Abstrakt: |
A method has been developed for the carbon‐14 radiosynthesis of non‐narcotic morphine derivative (R)‐(‐)‐[6a‐14C]apomorphine (1) from the starting material 3,4‐dimethoxy‐2‐nitrophenyl‐N‐phenethyl[carboxyl‐14C]acetamide (5). The key to this synthesis was the application of the Bischler–Napieralski cyclodehydration to 1‐(3,4‐dimethoxy‐2‐nitrobenzyl)dihydro[1‐14C]isoquinoline (4), followed by N‐methylation and reduction to 1‐(3,4‐dimethoxy‐2‐nitrobenzyl)‐2‐methyl‐1,2,3,4‐tetrahydro[1‐14C]isoquinoline (3). A final Pschorr reductive ring closure followed by chiral separation to give (R)‐(‐)‐[6a‐14C]apomorphine dimethyl ether (2) and O‐demethylation led to (R)‐(‐)‐[6a‐14C]apomorphine (1) with a specific activity of 55 mCi/mmol, radiochemical purity of >98% and chiral purity of >99%. Copyright © 2006 John Wiley & Sons, Ltd. |
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