Oligomeric flavanoids. Part 26. Structure and synthesis of the first profisetinidins with epifisetinidol constituent units
作者:Petrus J. Steynberg、Jan P. Steynberg、E. Vincent Brandt、Daneel Ferreira、Richard W. Hemingway
DOI:10.1039/a701334e
日期:——
The natural occurrence of the first oligomeric profisetinidins with
(2R,3R)-2,3-cis-epifisetinidol chain extender
units is demonstrated in the bark of Pithecellobium dulce
(Guamúchil). Semi-synthesis using the appropriate flavan-3-ol and
flavan-3,4-diol precursors permits unequivocal structural and
stereochemical assignment of the novel dimeric
epifisetinidol-(4β,8)-catechin and epicatechins 16 and 18,
the trimeric
bis-epifisetinidol-(4β,6:4β
,8)-catechin and epicatechins 33 and 35, the
fisetinidol-(4α,8)-catechin-(6,4β)-
epifisetinidol 37 and
fisetinidol-(4α,8)-epicatechin-(6,4β)-
epifisetinidol 39.
在甜根子草(Pithecellobium dulce)的树皮中,首次发现了含有(2R,3R)-2,3-顺式-表非瑟罗吲哚链延展单元的第一批寡聚原花青素。通过使用适当的黄烷-3-醇和黄烷-3,4-二醇前体进行半合成,可以明确确定新型二聚体表非瑟罗吲哚-(4β,8)-儿茶素和表儿茶素16与18、三聚体双表非瑟罗吲哚-(4β,6:4β,8)-儿茶素和表儿茶素33与35、非瑟罗吲哚-(4α,8)-儿茶素-(6,4β)-表非瑟罗吲哚37和非瑟罗吲哚-(4α,8)-表儿茶素-(6,4β)-表非瑟罗吲哚39的结构和立体化学。