Linkage Isomerism in Trimeric and Polymeric 2.3.cis-Procyanidins
نویسنده
چکیده
Four procyanidin trimers have been isolated and their structures unequivocally established as: epicatechin(4~+8)'epicatechin-(4~+8)-catechin (5); epicatechin-(4~-+6)-epicatechin-(4~-8)-catechin (6); epicatechin(4~8)-epicatechin-(4~6)-catechin (7); and epicatechin-(4~-8)-epicatechin-(4~-+8).epic8techin (13), The presence of the first three trimers in Pinus tBeds phloem. and the isolation of both epicatechin-(4f'-+8)-4~benzylthioepicatechin (9) and epicatechin-(4~-+6)-4~-benzylthioepicatechin (10) from partial acid-catalyzed cleavage of the tannins from Pinus pBlustris phloem and PhotiniB glsbrescens leaves. shows that linkage isomerism exists in natural oligomeric and polymeric procyanidins. A new system of nomenclature for proanthocyanidins is proposed.
منابع مشابه
Polymeric Proanthocyanidins: Interflavanoid Linkage Isomerism in (Epicatecbin .4).( epicatechin -4)-catecbin Procyanidins
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