Ledgerquinone (1,4-dimethoxy-2,3-methylenedioxyanthracene-9,10-dione), isolated from the callus tissue of Cinchona ledgeriana, has been prepared by intercepting the benzyne, 3,6-dimethoxy-4,5-methylenedioxy-1,2-didehydrobenzene, with the anion of 3-oxo-1,3-dihydroisobenzofuran-1-carbonitrile.
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