摘要 |
The present method provides a short, convergent total synthesis of novel intermediates in the synthesis of (+/-)-camptothecin and related compounds. The synthesis scheme includes a novel 4+1 radical annulation followed by another cyclization to simultaneously assemble rings B and C of the Camptothecin compound. In the synthesis, the following novel precursor is reacted with a phenyl isocyanide: <IMAGE> The resulting tetracyclic intermediates comprise a quinoline fused to a pyrrolidine ring, with the pyrrolidine ring being fused to an alpha-pyridone ring. The tetracyclic intermediates thus comprise the A, B, C, and D rings characteristic of camptothecin and camptothecin derivatives, and are easily convertible to camptothecin and camptothecin derivatives via hydroxymethylation and oxidation.
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