Studies on the Biosynthesis of Paraherquamide: Synthesis and Incorporation of a Hexacyclic Indole Derivative as an Advanced Metabolite This work was supported by the National Institutes of Health (Grant no. CA70375 to R.M.W.). We wish to acknowledge the American Chemical Society Division of Organic Chemistry Fellowship (sponsored by SmithKline Beecham) and the Pharmacia-Upjohn Company for financial support (to E.M.S.). Mass spectra were obtained on instruments supported by the National Institutes of Health Shared Instrumentation Grant (No. GM49631). We also wish to thank Professor Dean Crick of the Department of Microbiology at Colorado State University for helpful discussions. J.F.S.-C. thanks the DGICYT of Spain for a research grant (project no. PB98-1438).