Synthesis and Stereochemistry of Indolactam Congeners. Conformational Behavior of the Nine-membered Lactams.

Article abstract of DOI:10.1016/S0040-4020(01)86857-5

The potent tumor promoters teleocidins and (-)-indolactam-V, which is a biologically active partial structure, exist in two conformational states (SOFA and TWIST forms) in solution.In order to examine the effect of the C-12 isopropyl group, a series of indolactams having a methyl, benzyl, isobutyl or tert-butyl group at the C-12 position instead of the isopropyl group have been synthesized. ¹H-NMR measurements have shown that incresing bulkiness of the substituent on C-12 tends to increase the relative population of the SOFA conformer.