Lignans and related phenols. Part 18. The synthesis of quinones from podophyllotoxin and its analogues

The preparation of quinones from podophyllotoxin and peltatins of the aryltetrahydronaphthalene class by oxidative demethylation is described. The derivation of 2′-substituted ortho-quinones from these products by the reductive addition of azide, bromide, and chloride and subsequent oxidation by periodate is reported. Acid-catalysed reactions of ortho-quinones with alcohols are described including an unusual example of reductive methylation.