Quercus stenophylla

Nonaka, G., Nishimura, H., and Nishioka, L, Tannins and related compounds. Part 26. Isolation and structures of stenophyllanins A, B and C, novel tannins from Quercus stenophylla, J. Chem. Soc., Perkin Trans. 1, 163, 1985. 

Constit. of Gleichenia glauca and Quercus stenophylla. Amorph. powder -I- IH2O. [aj —36.2 (c, 0.24 in Mc2CO). 

Isol. from Quercus sessiliflora, Quercus stenophylla and Castanea sativa (sweet chestnut). Off-white amorph. powder. 

C27H24O17 620.476 Tannin constit. of Quercus stenophylla. Needles + H2O (H2O). 

C34H28O21 772.583 Tannin constit. of Quercus stenophylla. Off-white amorph. powder + 5H2O. [a]g +34.3 (c, 0.14 in MeOH). 

C27H24O17 620.476 Gallotannin from the bark of Quercus stenophylla. Off-white amorph. powder + IH2O. [a]g +15.6 (c, 0.27 in MeOH). I,2,3,4-Tetrakis-0-(3,4,5-trihydroxybenzoyl) l,2,3,4-Tetra-0-galloyl-scy o-quercitol [107724-19-6]... 

Nonaka, G.-i., Nishimura, H. Nishioka, I. (1985). Isolation and structures of stenophyUanins A, B, and C, novel tannins fiom Quercus stenophylla. Journal of the Chemical Society, Perkin Transactions 1,163-172. 

Illicium religiosum Casuarina equisetifolia Anogeissus tatifolia Sapium japonicum S. siebiferum Aleurites cordata Quercus stenophylla Q. pedunculata Ginkgo biloba Mammea americana Hama metis spp. 

Kamano Y, Tachi Y, Otake T, Sawada J 1977 Studies on the constituents of Quercus spp. VIII. Constituents of Quercus stenophylla Makino. Yakugaku Zasshi 97 1131-1133... 

Catechins are particularly good nucleophiles, so it is not surprising to find these compounds substituted at the A-ring with other natural products. The bark of Quercus stenophylla contains ellagitannins that are linked by carbon carbon bonds to the C-6 or C-8 of catechin (277). Kopsirachin (25), from Kopsia dasyrachis, is a most interesting example of this type of catechin derivative in which both the C-6 and C-8 positions are substituted by the alkaloid skytanthine (160). Other examples of this type of compound are the C-6, C-8, and C-6 -l- C-8 cinnamate derivatives of catechin isolated from Cinchona succirubra (273, 279). It can be predicted that many more examples of this type of catechin derivative will be found in the future. 

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