The Structure of Chalybaeizanic Acid and Quaesitic Acid, Two New Lichen Depsidones Related to Salazinic Acid

Authors:
  • JEJohn A. Elix
    John A. Elix
  • JWJudith H. Wardlaw
    Judith H. Wardlaw
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Abstract
The depsidones chalybaeizanic acid (1,4,10-trihydroxy-8-methyl-3,7-dioxo-1,3-dihydro-7 H -isobenzofuro- [4,5- b ][1,4]benzodioxepin-5,11-dicarbaldehyde) (4) and quaesitic acid (11-formyl-1,4,10-trihydroxy-8- methyl-3,7-dioxo-1,3-dihydro-7 H -isobenzofuro[4,5- b ][1,4]benzodioxepin-5-methyl hydrogen fumarate) (5) have been isolated from the lichens Xanthoparmelia amphixanthoides and Hypotrachyna quaesita respectively, and their structures determined by a combination of spectroscopic evidence, partial synthesis, derivatization or degradation reactions.