Cleistanthus schlechteri

Pimarane diterpenes with an antipodal backbone have been isolated from Cleistanthus schlechteri. These included ent-3)8-hydroxypimara-8,l5-diene, ent-3)3,12 -dihydroxypimara-8,l 5-diene (16), and the corresponding C-12 ketone. The location of the carbonyl group at C-12 was inferred from bromination and dehydrobromination and from the multiplicity of the C—H resonance of the C-12 alcohol. Macarangonol (17) has been isolated from Macaranga tanarius. 

Cleistanthol (42), isolated from Cleistanthus schlechteri, is an unusual diter-pene. In contrast to the cassane diterpenes, its structure results from formal... 

Representatives of naturally occurring cleistanthanes include (+)-13(17),15-clei-stanthadiene from Amphibolis antarctica, (+)-auricularic acid from Pogostemon auricularis (Labiatae), the antineoplastic (-)-spruceanol from Cunurea spruceana and (-)-cleistanthol from Cleistanthus schlechteri (Euphorbiaceae). 

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