New clerodane diterpenoids from Casearia sylvestris.

Two new clerodane diterpenoids 2 beta-methoxy-cleroda-3,13-dien-18-carboxy-15,16-olide (1) and 15 xi-methoxy-cleroda-3,12-dien-18-carboxy-15,16-olide (2) and one new nitrogen-containing clerodane diterpenoid 15-oxo-echinophyllin A (3), along with six known compounds, namely, echinophyllin A, (-)-patagonic acid, tyrosol, oplopanone, 4-hydroxy-4-methyl-2-[(1R)-1-(1-methylethyl)-4-oxopentyl]-2-cyclohexen-1-one and 1 beta,6 alpha-dihydroxy-eudesman-4(15)-ene were isolated from the leaves of Casearia sylvestris. Their structures were determined by extensive NMR techniques.