“…The two methoxy groups were assigned to positions C4 (d H 3.35, d C 77.4) and C15 (d H 3.30, d C 81.0). NOESY experiments allowed the assignment of the relative configuration of the stereogenic center at C2, which was opposite to that of secu'amamine B (10). Moreover, the CD spectrum of 15 was similar to that of secu'amamine C (11), and the absolute configuration was determined as 2R, 4S, 7S, 9S, and 15S.…”