抄録
Attempts were made to introduce an alcoholic hydroxyl group stereospecifically at the C-5 or C-6 position of 2, 3-dibenzylbutyrolactone lignans with lead tetraacetate and osmic acid as oxidizing agents. 5-Acetoxyarctigenin monoacetate (III) was obtained from arctigenin monoacetate (II), 5-acetoxyisoarctigenin monoacetate (XIII) from isoarctigenin monoacetate (XII) and 5-acetoxytrachelogenin diacetate (XXIII) from trachelogenin diacetate (XXII) by oxidation with lead tetraacetate in acetic acid. 6-Hydroxyisomethyltrachelogenin (XXXII) was obtained from 3-(3, 4-dimethoxybenzyl)-2-(3, 4-dimethoxybenzylidene) butyrolactone (XXXI) by oxidation with osmic acid. The 13C-NMR spectra of these oxidation products and analogs are discussed with regard to the differences of the chemical shifts resulting from changes in the substituents and the stereochemistry of the 2, 3-dibenzylbutyrolactone skeleton.
