Methyl 14-oxo-5α, 8β, 9α-podocarp-15-oate (4) is synthesized from methyl 13-isopropyl-7-oxopodocarpa-5, 8, 11, 13-tetraen-15-oate (5) by combination of the following processes : nitration at the 14-position ; conversion of the nitro group into the hydroxy group ; deisopropylation ; reductions of the enone function and C ring ; oxidation of the 14-hydroxy group to the oxo group.
