117933-38-7

Downstream Products

• 97743-92-5 deca-O-methyl-β-gemin D 
• 97743-92-5 deca-O-methyl-α-gemin D 
• 97743-92-5 C₃₇H₄₂O₁₈ 
• 149-91-7 3,4,5-trihydroxybenzoic acid 
• 23094-68-0 (11aR,14R,15R,15aS)-2,3,4,5,6,7,13,14,15-nonahydroxy-11,11a,13,14,15,15a-hexahydrodibenzo[g,i]pyrano[3,2-b][1,5]dioxacycloundecine-9,17-dione 

Relevant academic research and scientific papers

The First Total Syntheses of Enantiomerically Pure Naturally Occuring Ellagitannins Gemin D and its Regioisomer Hippomanin A

The total syntheses of naturally occuring ellagitannins gemin D (1) and its regioisomer hippomanin A (2) are reported. In addition, the phase-transfer catalyzed benzylation reaction of the 2,3-glucopyranoside diols 3-7 is described. Our studies have illustrated the influence of the structure of 2,3-glucopyranoside diols on the regioselectivity of the phase-transfer catalyzed benzylation at their free 2,3-OH groups. We could show, that both phase-transfer catalyzed benzylations of 2,3-glucopyranoside diols using tetrabutylammonium hydrogensulfate (Bu4NHSO4) or using tetrabutylammonium iodide (Bu4NI) disfavour the formation of the corresponding 3-O-monobenzylated products and preferentially give the 2-O-monobenzylated products. However, the ratio of the generated 2- versus 3-O-mono- and 2,3-dibenzylated products from these reactions also strongly depends upon the nature of the starting materials. The glucopyranosides 3 and 4 are the first examples, which allow the completely regioselective monobenzylation at the 2-OH positions by a phase-transfer catalyzed reaction.

Tannins of theaceous plants. V. Camelliatannins F, G and H, three new tannins from Camellia japonica L.

Two new complex tannins, camelliatannins F (3) and G (4), were isolated from the leaves of Camellia japonica L. (Theaceae), and their structures, each consisting of an epicatechin unit and a C-glucosidic ellagitannin moiety, were elucidated. A new dimeric hydrolyzable tannin, named camelliatannin H (5), was isolated from the fruits of this plant. Camelliins A (6) and B (7), and camelliatannin A (1) and 3 were also isolated from the fruits.

Woodfordin D and oenothein A, trimeric hydrolyzable tannins of macro-ring structure with antitumor activity

Two new antitumor trimeric hydrolyzable tannins, woodfordin D (5) and oenothein A (13), were isolated from the dried flowers of Woodfordia fruticosa, and their macrocyclic structures, which have a novel constituent unit (woodfordinoyl group) connecting the monomers, have been elucidated on the basis of spectral and chemical evidence. Oenothein A (13) was also isolated from the leaves of Oenothera biennis.

Tannins of cornaceous plants. I. Cornusiins A, B and C, dimeric monomeric and trimeric hydrolyzable tannins from Cornus officinalis, and orientation of valoneoyl group in related tannins.

Cornusiin A (1), cornusiin B (2) and cornusiin C (3), new dimeric, monomeric and trimeric hydrolyzable tannins, were isolated from the fruits of Cornus officinalis (Cornaceae). Their structures, including the orientation of the valoneoyl group in 1 and 3, were established on the basis of chemical and spectroscopic data. 2,3-Di-O-galloyl-D-glucose (7), 1,2,3-tri-O-galloyl-beta-D-glucose, 1,2,6-tri-O-galloyl-beta-D-glucose, 1,2,3,6-tetra-O-galloyl-beta-D-glucose, gemin D (5), isoterchebin, tellimagrandin I (6) and tellimagrandin II were also isolated from the fruits. The orientation of the valoneoyl group in camptothin A (14) and that in camptothin B (15), which had been isolated from Camptotheca acuminata (Nyssaceae), were also determined based on that in 1.