CHEMICAL MODIFICATION OF PARAHERQUAMIDE .2. REPLACEMENT OF THE C-14 METHYL-GROUP

Paraherquamide (1) is a toxic metabolite of Penicillium paraherquei that was reported several years ago by Yamazaki et al.2,3 It is structurally related to the marcfor-tines that were isolated from P. roqueforti by Polonsky et al.4 The unusual structures of these oxindole alkaloids have recently begun to attract the attention of synthetic chemists.5 The discovery that 1 and several natural analogues are potent antiparasitic agents6 prompted us to begin a program of chemical modification of paraherqu- amide. We recently described several interesting reactions of 1 and reported its absolute stereochemistry.1 We have also been studying the replacement of the methyl group at C-14 and in this paper we report a series of reactions that accomplishes this useful transformation. © 1990, American Chemical Society. All rights reserved.