Diterpenes and other components of Croton hirtus (Euphorbiaceae)

Abstract

The roots of Croton hirtus (Euphorbiaceae) collected in Paraiso, Cartago (Costa Rica) afforded, in addition to the few known metabolites, 20 new compounds: the bis-nor dolabradane 1, the dolabradanes 2 and 3, the kauranes 4-7, the cyclopropakauranes 8 and 9, the hirtusanes 10-15, the germacradiene esters 16-18 and the C-25 compound 21, presumably formed by a Diels-Alder reaction between compound 18 and a monoterpene. All structures were elucidated using high field 1D and 2D NMR techniques. MS fragmentation patterns are here reported. The absolute configurations of 4 and 9 were elucidated by using circular dichroism. The separation was performed with modern chromatographic technics.