CLERODANE DITERPENES FROM CASEARIA-CORYMBOSA STEM BARK

Fifteen diterpenes have been isolated from the stem bark of Casearia corymbosa. Nine of these are novel and have been characterized, on the basis of spectral data and comparison with known compounds, as (relative stereochemistry) ent-2β-hydroxy-3,4-dihydro-4α-isozuelanin, ent-3,4-dihydro-4α-isozuelanin-2β-acetate, ent-3,4-dihydro-4α-isozuelanin-2β-(2-methyl)-butyrate, 18-hydroxy-2-oxo-8β,9β,10α-cleroda-3,13(16),14-triene, 18,19α-diacetoxy-2-oxo-8β, 9β,10α-cleroda-3,13(16),14-triene, ent-6β-hydroxyisozuelanin-2β-(2-methyl)butyrate, ent-6β-hydroxyisozuelanin-2β-(2-methyl)propanoate, ent-6β-methoxyisozuelanin-2β-(2-methyl)butyrate, and ent-6β-methoxyisozuelanin-2β-(2-methyl)propanoate. In addition six known diterpenes [ent-(-)-kaur-16-en-3β-ol, 3α-hydroxy-(-)-13-epimanoyl oxide, (-)-13-epimanoyl oxide, ent-(-)-kaur-16-en-19-oic acid, ent-(-)-kaur-16-en-19-al and ent-(-)-kaur-16-en-19-ol acetate] and the sesquiterpene caryophyllene-4,5-oxide were isolated. © 1990.