NMR AND MOLECULAR MODELING STUDY OF PACLITAXEL PUTATIVE PRECURSORS

Isolation and purification procedures for the bicyclic oxygenated taxa ne canadensene, obtained from Taxus canadensis are reported. Molecular modeling studies of canadensene, baccatin III (the core structure of paclitaxel), paclitaxel, taxa-4(5),11(12)-diene (the biosynthetic prec ursor of paclitaxel) and putative derivatives were performed. NMR cons traints were obtained for canadensene and baccatin III. A striking U-s hape for canadensene was obtained in the 3D-model. Biosynthetic pathwa ys for the formation of canadensene are proposed. Copyright (C) 1996 E lsevier Science Ltd