Ruakuric Acid: A Natural Product from Aspergillus fumigatus.

A new chroman derivative, named ruakuric acid, was isolated from a strain of Aspergillus fumigatus growing in conjunction with a coral lichen. The structure was determined as 6-acetyl-5-hydroxy-4-methoxy-chroman-2-carboxylic acid (mixture of 2,4-cis,trans isomers).