7β-Oxygenated limonoids from Trichilia elegans ssp. elegans

Abstract

Five 7β- and 7α-oxygenated obacunone-type limonoids were obtained on reinvestigation of the seeds of Trichilia elegans ssp. elegans: 7-deoxo-7β-acetoxykihadanins A and B, 7-deoxo-7β-hydroxykihadanins A and B and 7-deoxo-7α-hydroxykihadanin A, the last three being isolated after acetylation procedures as their mono- and/or diacetate derivatives. This is the first report of the natural occurrence of C-7 β-substituted limonoids without any oxygenated function at C-6. The structures of these compounds have been established on the basis of 1D- and 2D-NMR spectral techniques, ESI-mass spectrum and X-ray crystallographic data.