Stereoselective Total Synthesis of Radiolabeled Artemisinin (Qinghaosu).
Final rept. 15 Nov 87-14 Jun 89,
SRI INTERNATIONAL MENLO PARK CA
Pagination or Media Count:
Our previous total synthesis of -artemisinin has been optimized from 18 to 11 steps. The final two steps in the sequence are 1 alkylation of a carboxylic acid dianion with methyl iodide, and 2 ozonolysis of a vinyl-silane followed by in situ acid-catalyzed cyclization to provide the natural product -artemisinin. The first step was repeated utilizing carbon-14 methyl iodide and the sequence completed as before to afford the desired carbon-14labeled -artemisinin. The label resides in the methyl group pendant from the lactone ring ring D, the position of attachment being C-9, the carbon atom being C-16. Keywords Antimalarials. aw