Total synthesis of ochnaflavone

• Monica M. Ndoile and
• Fanie R. van Heerden

Beilstein J. Org. Chem. 2013, 9, 1346–1351, doi:10.3762/bjoc.9.152

• moieties, and the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone have been achieved. The key steps in the synthesis of ochnaflavone were the formation of a diaryl ether and ring cyclization of an ether-linked dimeric chalcone to assemble the two flavone nuclei. Optimal experimental conditions for

• the oxidative cyclization to form ochnaflavone were established. Keywords: biflavone; diaryl ether; natural products; nucleophilic aromatic substitution; ochnaflavone; tetrahydroochnaflavone; Introduction Biflavonoids are a class of compounds that are receiving increasing attention because of their

• interconvertibility of the two compounds through chalcone–flavanone equilibrium [29][30] (Scheme 2). Biflavanone 8 is the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone, a natural product isolated from the New Zealand tree Quintinia acutifolia, which is cytotoxic against P388 murine lymphocytic leukemia cells