Studies in the biochemistry of micro-organisms. 91. The colouring matters of Penicillium islandicum Sopp. Part 3. Skyrin and flavoskyrin

Publisher Website
Google Scholar
Abstract
Two hitherto undescr. coloring matters, skyrin and flavoskyrin, were isolated from the mycelium of laboratory cultures of a morphologically typical but biochemically atypical strain of P. islandicum. Skyrin, C30H18O10, crystallizes as clusters of orange-red rods or as yellow, hexagonal plates and does not melt below 380[degree]. Several of its derivatives are described. When an alkaline solution of skyrin is treated with sodium dithionite, Na2S2O4, it undergoes reductive cleavage into two molecules of emodin, C15H12O5, 4:5:7-trihydroxy-2-methylanthraquinone. Flavoskyrin, C15H12O5, crystallizes as yellow needles, m.p. 215[degree] (decomp.) Flavoskyrin loses a molecule of water to yield chrysolphanol, C15H12O5, 4:5-dihydroxy-2-methyl-anthraquinone, either by heating at its melting point or by the action of cold concentrated sulphuric acid. The chrysophanol already reported as a metabolic product of this strain of P. islandicum was shown not to be an artifact produced, during its isolation, by decomposition of flavoskyrin. Possible structures for skyrin are discussed.