EPIMERIZATION OF ANNONACEOUS ACETOGENINS UNDER BASIC CONDITIONS

In basic conditions, non-4-hydroxylated annonaceous acetogenins may be epimerized by light basic treatment. The two epimers are inseparable by HPLC, have identical spectroscopic data CMS, IR, UV, H-1 and C-13 N MR). However, specific rotation of the epimeric mixture and enzymatic oxidation after chemical degradation, allow us to characterize this ep imerization. In tile same reaction conditions, 4-hydroxylated annonace ous acetogenins led to isoacetogenins. (C) 1997 Elsevier Science Ltd.