Eight new clerodane diterpenoids from the bark of Ptychopetalum olacoides

Abstract

Eight new clerodane type diterpenoids, named 7-oxo-kolavelool (1), 7α-hydroxykolavelool (2), 6α,7α-dihydroxykolavenol (3), 12-oxohardwickiic acid (4), ptycholide I (5), ptycholide II (6), ptycholide III (7), and ptycholide IV (8) were isolated from the MeOH extract of the bark of a Brazilian medicinal plant, Ptychopetalum olacoides. The structures of 1-8 were elucidated by analyzing spectroscopic data and by comparing their NMR data with those of the previously reported compounds kolavelool (1a), kolavenol (3a), hardwickiic acid (4a), and ptychonolide (5a). Compounds 5 and 6 existed as a 1:1 mixture of inseparable epimers at C-15.