37064-37-2

Upstream product

• 37064-35-0 4β-benzylthioepicatechin 
• 108-24-7 acetic anhydride 

Relevant academic research and scientific papers

PROCYANIDINS AND POLYPHENOLS OF LARIX GMELINI BARK

Key Word Index - Larix gmelini; Pinaceae; bark; catechins; procyanidins; biflavonoids; larixinol.Methanol extracts of Larix gmelini bark yielded (-)-epiafzelechin, (+)-catechin and (-)-epicatechin, dimeric procyanidins B-1, B-2, B-3 and B-4 and oligomeric procyanidins.Chemical degradation of the oligomers using toluene-α-thiol and acetic acid showed the oligomers to have flavan-3-ol terminal units possessing either the 2,3-trans (catechin) or 2,3-cis (epicatechin) stereochemistry, with the former predominating.Likewise the extension units were shown to consist of flavan-3-ol units with 2,3-trans or 2,3-cis stereochemistry in roughly equal proportion.The average degree of oligomerization was calculated as 6-7 and the number average molecular weight as 1700-2000.The structure of the residual procyanidins remaining in the bark after methanol extraction is also briefly commented upon.Larixinol is shown to have an unusual spirobiflavonoid structure and a pathway of biogenesis is proposed.

THIOLYSIS OF BIRCH BARK PROCYANIDINES: STRUCTURAL DEPENDENCE IN FORMATION OF 2,3-CIS-3,4-CIS-FLAVAN-4-BENZYLTHIOETHERS FROM PROCYANIDINS

Thiolytic studies of the birch bark procyanidins, epicatechin-(4β->8)-catechin (B1), epicatechin-(4β->6)-catechin (B7) and epicatechin-(4β->8)-epicatechin-(4β->8)-catechin, provided, in addition to known β-thioethers, evidence for the presence of the first 2,3-cis-3,4-cis-flavan-4-benzylthioethers.Their formation is dependent on the 2,3-stereochemistry of the 'lower' terminal flavan unit and apparently on the relative lability of the interflavanoid linkage.By contrast, epicatechin-(4β->8)-epicatechin (B2), epicatechin-(4β->6)-epicatechin (B5) and epicatechin-(4β->8)-epicatechin-(4β->8)-epicatechin (C1), afforded only 2,3-cis-3,4-trans-flavan-4-benzylthioethers.