On the Biosynthesis of Toluquinones from Aspergillus fumigatus. IV. Biogenetic Relations of the Pigments.

Abstract

The interrelationships of the toluquinonoid pigments produced by A. fumigatus, L.S.H.T.M. A 46, has been investigated by observing the pattern of incorporation of 3-hydroxy-2,5-toluhydroquinone (I) and 3,4-dihydroxy-2,5-toluhydroquinone (HI). The former compound was found to be converted as a unit into 3,6-dihydroxy-2,5-toluhydroquinone (II), a reaction that is analogous to the hydroxylation of fumigatin hydro-quinone (V), by which spinulosin hydroquinone (VI) appears to be formed. 3,4-Dihydroxy-2,5-toluhydroquinone was incorporated into all of the pigments that contain a methoxyl group. Further experiments, including short-term studies of the utilization of l-Cl4-acetate for pigment formation, established that 3,4-dihydroxy-2,5-toluhydroquinone is a possible natural precursor of, for instance, fumigatin.