Clerodane diterpenoids from Salvia splendens.

Four new clerodane diterpenoids, salvisplendins A-D (1-4), have been isolated from an acetone extract of the flowers of Salvia splendens, together with an artifact (5), arising from salvisplendin D (4) by addition of diazomethane, and the already known clerodane olearin (6). The structures of the new compounds (1-5) were established mainly by 1D and 2D NMR spectroscopic studies and, in the case of salvisplendin A (1), by chemical correlation with splenolide B (7). Complete 1H and 13C NMR assignments for olearin (6), not published hitherto, are also reported.