Biosynthetic Study of Amphidinolide B

Abstract

The biosynthetic origins of amphidinolide B (1) were investigated on the basis of ¹³C-NMR data of ¹³C-enriched samples obtained by feeding experiments with [1-¹³C], [2-¹³C], and [1,2-¹³C₂] sodium acetates in cultures of a dinoflagellate Amphidinium sp. These incorporation patterns suggested that 1 was generated from three successive polyketide chains, an isolated C₁ unit from C-2 of acetates, six branched C₁ units from C-2 of acetates, and an “m-m” and an “m-m-m” unit derived only from C-2 of acetates. The labeling patterns of amphidinolide B (1) were different from those of amphidinolide H (2), a 26-membered macrolide closely related to 1.