Absolute stereostructure of Andirolides A–G from the flower of Carapa guianensis (Meliaceae)

A new gedunin, three new mexicanolides and three new phragmalin-type limonoids named Andirolides A (1), B (2), C (3), D (4), E (5), F (6), and G (7) were isolated from oil of the flower of Carapa guianensis Aublet (Meliaceae). Their absolute stereostructures were determined by 2D NMR and CD spectra, and single-crystal X-ray analysis, and all compounds were confirmed to have the C-17βH configuration. Considering the similarity in CD spectra between Andirolide G (7) and the xyloccensins reported by Wu, we concluded that the structures of xyloccensins should be revised so as to have the absolute configuration of 17R.