Rearranged taxoids from Taxus yunnanensis

Two rearranged 2(3-->20)abeotaxanes were isolated from the leaves and stems of Taxus yunnanensis, and designated as taxin B and 2-deacetyltaxin B. The structure of taxin B with a unique 6/10/6 skeleton was deduced on the basis of 1H-NMR, 13C-NMR, 1H-1H COSY, DEPT, NOE, and mass spectra and confirmed by X-ray crystallographic analysis. The structure of 2-deacetyltaxin B is elucidated by analog.