The Structure of Isopannarin

Article abstract of DOI:10.1071/CH9831057

The structure proposed by Yosioka for the product obtained by the treatment of the depsidone pannarin (2-chloro-3-hydroxy-8-methoxy-1,6,9-trimethyl-11-oxo-11H-dibenzo<1,4>dioxepin-4-carbaldehyde) (2) with concentrated sulfuric acid is revised to 5-chloro-6-hydroxy-4'-methoxy-2',4,5'-trimethyl-3,6'-dioxo-2,3-dihydrospiro-7-carbaldehyde (5).