517-46-4Relevant academic research and scientific papers
First Total Synthesis of Neostrictinin
Ikeuchi, Kazutada,Ueji, Tatsuya,Matsumoto, Shintaro,Wakamori, Shinnosuke,Yamada, Hidetoshi
, p. 2077 - 2085 (2020/03/23)
Herein, we describe the first total synthesis of neostrictinin, a natural ellagitannin bearing a (R)-hexahydroxydiphenoyl (HHDP) bridge between the 4- and 6-oxygens of d-glucose. Among the multitude of 4,6-O-HHDP bridged ellagitannins, (R)-axial chirality of the HHDP bridge is quite rare as it is less stable than the corresponding (S)-isomer. The labile bridge was constructed using a two-step bislactonization that involved: (1) monoacylation of the primary alcohol of ethyl 2,3-O-benzyl-1-thio-β-d-glucopyranoside using protected (R)-hexahydroxydiphenic anhydride and (2) intramolecular lactonization of the obtained seco acid by treatment with a Mukaiyama condensation reagent (2-chloro-N-methylpyridinium iodide) and 2,6-lutidine. Structural confirmation of the synthesized neostrictinin and the preparation of its epimer are also reported.
Total synthesis of ellagitannins through regioselective sequential functionalization of unprotected glucose
Takeuchi, Hironori,Mishiro, Kenji,Ueda, Yoshihiro,Fujimori, Yusuke,Furuta, Takumi,Kawabata, Takeo
, p. 6177 - 6180 (2015/05/20)
Short total syntheses of natural glycosides (ellagitannins) were performed through sequential and regioselective functionalization of the hydroxy groups of unprotected glucose. The key reactions are β-selective glycosidation of a gallic acid derivative by using unprotected glucose as a glycosyl donor and catalyst-controlled regioselective introduction of a galloyl group into the inherently less reactive hydroxy group of the glucoside.
TANNIN INHIBITORS OF HIV
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Paragraph 0029; 0036, (2013/10/07)
The invention provides a method to prevent or treat HIV-infection with synthetic tannins, and pharmaceutical compositions comprising synthetic tannins.
Roxbin B is cuspinin: Structural revision and total synthesis
Yamaguchi, Sayuri,Hirokane, Tsukasa,Yoshida, Takashi,Tanaka, Takashi,Hatano, Tsutomu,Ito, Hideyuki,Nonaka, Gen-Ichiro,Yamada, Hidetoshi
, p. 5410 - 5417 (2013/07/26)
Prompted by the outcome that the synthesized roxbin B was not identical to the natural roxbin B, the structural determination process and spectral data were re-examined, with the finding that roxbin B was very likely to be 1-O-galloyl-2,3-(R);4,6-(S)-bis-
Synthesis of enantiomerically pure strictinin using a stereoselective esterification reaction
Khanbabaee, Karamali,Schulz, Christian,Loetzerich, Kerstin
, p. 1367 - 1368 (2007/10/03)
The total synthesis of strictinin (4) has been achieved using a diastereoselective esterification of benzyl protected hexahydroxydiphenic acid 1 with D-glucose derived sugar 2.
Tannins and related polyphenols of melastomataceous plants. III. Nobotanins G, H and I, dimeric hydrolyzable tannins from Heterocentron roseum
Yoshida,Haba,Nakata,Okano,Shingu,Okuda
, p. 66 - 71 (2007/10/02)
Three new hydrolyzable tannin dimers, nobotanins G (6), H (12) and I (13), have been isolated from the leaves of Heterocentron roseum (Melastomataceae), and their structures were elucidated on the basis of chemical degradations and nuclear magnetic resonance spectral analyses. Nobotanin I (13) is a novel dimer possessing a depsidone-forming valoneoyl group in the molecule. Five known tannins, casuarictin (1), strictinin (2), geraniin (3), and nobotanins B (4) and F (5), were also isolated.
Tannins and Related Compounds. LXXVI. Isolation and Characterization of Cercidinins A and B and Cuspinin, Unusual 2,3-(R)-Hexahydroxydiphenoyl Glucoses from Cercidiphyllum japanicum and Castanopsis cuspidata var. sieboldii
Nonaka, Gen-ichiro,Ishimatsu, Makoto,Ageta, Masayuki,Nishioka, Itsuo
, p. 50 - 53 (2007/10/02)
Cercidinins A (1) and B (2) and cuspinin (3), unusual ellagitannins having an R-hexahydroxydiphenoyl ester group at the glucose 2,3-positions, have been isolated from the bark of Cercidiphyllum japonicum (Cercidiphyllaceae) and the leaves of Castanopsis cuspidata var. sieboldii (Fagaceae).On the basis of chemical and spectroscopic evidence, their structures were established as 1,4,6-tri-O-galloyl-2,3-(R)-hexahydroxydiphenoyl-β-D-glucose (1), 4,6-di-O-galloyl-2,3-(R)-hexahydroxydiphenoyl-D-glucose (2) and 1-O-galloyl-2,3-(R);4,6-(S)-hexahydroxydiphenoyl-β-D-glucose (3).The co-occurrence of 3 with the atropisomeric S-hexahydroxydiphenoyl derivative suggests the non-specificity of the enzyme which converts gallic acid to hexahydroxydiphenoic acid.Keywords: Cercidiphyllum japonicum; Cercidiphyllaceae; Castanopsis cuspidata var. sieboldii; Fagaceae; cercidinin A; cercidinin B; cuspinin; ellagitannin; 2,3-(R)-hexahydroxydiphenoyl glucose; atropisomerism
