The synthesis of various 2H-1,5-benzodioxepin and 2,5-dihydro-1,6-benzodioxocin derivatives is described. The key step involves the construction of seven- and eight-membered rings via ring-closing metathesis reaction. (C) 2004 Elsevier Ltd. All rights reserved.
Isotopic labelling of quercetin 3-glucoside
作者:Stuart T. Caldwell、Hanna M. Petersson、Louis J. Farrugia、William Mullen、Alan Crozier、Richard C. Hartley
DOI:10.1016/j.tet.2006.05.046
日期:2006.7
13C-labelled at C-2 of the flavonoid unit by synthesis in 15% yield over five steps from [13C]carbon dioxide. The route is appropriate for radiochemical synthesis. Formation of the protected 3-glucosylated flavonol appears to result from [1,7]-sigmatropic rearrangement with migration of a benzyl group followed by cyclisation. A free 5-OH results even when a phosphazene superbase is used.
潜在重要的饮食抗氧化剂槲皮素3 - O -β-d-葡萄糖苷已通过从[ 13 C]二氧化碳经过5步合成,以15%的产率在类黄酮单元的C-2处被13 C标记。该路线适用于放射化学合成。受保护的3-葡萄糖基化黄酮醇的形成似乎是由[1,7]-σ重排导致的,其中苄基迁移,然后环化。即使使用磷腈超强碱,也会产生游离的5-OH。