19 ビスノルジテルペノイド,イヌマキラクトンの構造

概要

論文の詳細を見る
From the seeds of Podocarpus macrophyllus D. DON, a bisnorditerpenoid dilactone, inumakilactone (I), C_<18>H_<20>O_8, m.p. 251-253°(decomp),[α]_D^<±0°, was isolated together with nagilactone C^3. The presence of two secondary hydroxyl groups and a γ-lactone and an α,β-unsaturated-δ-lactone groupings in I was revealed by the acetylation, oxidation, hydrolysis and hydrogenation experiments; two inhert oxygens were concluded to be etheric. The partial structures [A]-[E] established by NMDR of the diacetate II were advanced to [A],[E],[F] and [G]or[G']and then to the planer structure on the basis of close examination of NMR spectra of fourteen derivatives. Stereochemistry of the ring carbons was elucidated by careful analysis of the chemical shifts and the coupling constants of all the hydrogens in these derivatives, particularly by the optical rotation difference between the lactone II and the corresponding hydroxy-ester X and by ORD and CD of the epoxyketones, IX and XII. Configuration at C-15 was determined by the application of the benzoate rule and the Horeau's asymmetric synthesis. The derived structure I has a close similarity with those of totarol, its congeners and nagilactones, which have been isolated from the other Podocarpus species, suggesting their intimate biogenetic relationship.
天然有機化合物討論会の論文
1967-09-25