1961 年 81 巻 12 号 p. 1807-1808
From the leaves of Isodon trichocarpus KUDO, enmein, m. p. 297-298°(decomp.) was isolated together with a new bitter principle, dihydroenmein, which had heretofore been obtained by catalytic reduction of enmein. Dihydroenmein was not isolated by recrystallization or chromatography, but was isolated in an amount corresponding to 30% of crude enmein from the neutral portion left after removal of enmein as an acid substance after oxidation of crude enmein with potassium permanganate.