Tannins and Related Compounds. XXXIX.₁₎ Procyanidin C-Glucosides and an Acylated Flavan-3-ol Glucoside from the Barks of Cinnamomum cassia Blume and C. obtusifolium Nees

Along with procyanidins B-l (4), B-2 (5), B-5 (6) and B-7 (7), and the doubly linked proanthocyanidin, A-2 (8), two new procyanidin glucosides have been isolated from the bark of Cinnamomum cassia Blume (Lauraceae), and characterized as procyanidin B-2 8-C- and 6-C-β-D-glucopyranosides (1 and 2, respectively) on the basis of proton and carbon-13 nuclear magnetic resonance examinations and the results of thiolytic degradation. In addition, from the bark of Cinnamomum obtusifolium Nees an acylated flavan-3-ol glucoside (3) has been isolated, together with the known proanthocyanidins B-l (4), B-2 (5), B-5 (6) and A-2 (8). The structure of 3 has been established to be (+)-catechin 5-O-β-D-(2‘-O-feruloyl-6’-O-p-coumaroyl)-glucopyranoside on the basis of chemical and spectral evidence.