Tasumatrols P–T, Five New Taxoids from Taxus sumatrana

The phytochemical investigation of the more polar fractions from the leaves and twigs of Taxus
sumatrana (Taxaceae) afforded five new taxane diterpene esters, tasumatrols P –T (1 – 5) possessing an
11(15!1),11(10!9)-diabeotaxane skeleton. Compounds 1, 4, and 5 contain an a-hydroxy group at
C(14), while 3 has no OH group at either C(13) or C(14). Compound 2 is a natural 4,5-acetonide
derivative, while 4 has an unusual spiro-connected 2-hydroxy-2-phenyl-1,3-dioxolane ring. Ten known
taxoids, were also isolated in the course of the chromatographic fractionation. Five additional new Oacetyl
derivatives 3a, 4a, 4b, 5a, and 5b were prepared from the taxanes 3 – 5. The structures of all new
compounds were established on the basis of their spectroscopic analyses. Compound 1 showed mild
cytotoxic activity against human Hela and Daoy tumor cells.