Two novel and closely related tannins, designated as acutissimins A (1) and B (2), have been isolated from various Fagaceous plants: Quercus acutissima, Q. miyagii, Q. stenophylla, Q. mongolica var. grosseserrata and Castanea crenata. Degradative and synthetic studies combined with 1 H-and 13 C-NMR spectrometry and various mass spectral measurements have permitted the assignments. of the structures, in which (+)-catechin (4) ...
