Oligomeric flavanoids. Part 13. Synthesis of profisetinidins based on (−) robinetinidol and (+) -epifisetinidol
作者:Johannes C.S. Malan、Jacobus A. Steenkamp、Desmond A. Young、Daneel Ferreira
DOI:10.1016/s0040-4020(01)85799-9
日期:——
(−)-robinetinidol[(2R,3S)-2,3-trans-flavan-3,3′,4′,5′,7-pentaol] afforded a novel series of bi-, tri-, and tetraflavanoid profisetinidins. They are accompanied by (−)-fisetinidol-(4α,2′)-(−)-robinetinidol which results from the pyrogallol B-ring of (−)-robinetinidol serving as nucleophile competing with its resorcinol A-ring in coupling with a C-4 carbocationic intermediate. Similar condensation with
(+)-molacacacidin-[(2 R,3 S,4 R)-2,3- trans-3,4 - trans -flavan-3,3',4,4',7-戊醇的酸催化缩合]与过量的(-)-robinetinidol [(2 R,3 S)-2,3-反式黄酮-3,3',4',5',7-戊醇]提供了一系列新的双,三和四黄酮类prosetsetindins。它们伴随有(-)-菲塞蒂尼多-(4α,2')-(-)-罗比替尼醇,其起因于(-)-罗比替尼醇的邻苯三酚B环与亲和性间苯二酚A环竞争并与间苯二酚A环竞争。 C-4碳阳离子中间体。与(+)-epifisetinidol [(2S,3S)-2,3-cis-flavan-3,3',4',7-四醇]的类似缩合导致[4,6]-黄烷间键的排他性形成,与(-)-罗比替尼同系物的“分支”性质相反,这些单元以“线性”方式排列在四类黄酮类似物中。