Oxindole rings

About a dozen l-methoxy-2-oxindole alkaloids have been isolated and identified, either by X-ray crystallography or by sophisticated spectroscopy. Most are associated with their des-l-methoxy analogues in the plants. Very little chemistry involving the l-methoxy-2-oxindole ring system of these compounds has been done, and they will therefore be considered only briefly. 

Okita, T. and Isobe, M. 1994. Synthesis of the pentacyclic intermediate for dynemicin a and unusual formation of spiro-oxindole ring. Tetrahedron 50 11143-11152. 

The structurally related alkaloid marcfortine, first described by Polonsky et al. in 1980 [35] is rendered from two isoprene units, tryptophan and pipecolic acid. The structures of the members of this family of mold metabolites are presented in Fig. 4. The paraherquamides differ with respect to substitution and oxygenation in the proline ring and the prenyiated oxindole ring paraherquamide B is the simplest member of the paraherquamide family, being comprised of the amino adds proline, tryptophan, and two isoprene units. 

Heterocyclic Carboxamide Derivatives - In the carrageenin rat paw assay carboxanilides of the oxindole ring (.12) demonstrated antiinflammatory activity somewhat less potent than indomethacin, having long dog plasma half-lives,... 

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