Yellow Pigments of Aspergillus niger and Asp. awamori Part I

From mycelia of Asp. niger and Asp. awamori aurasperones A, B and C along with related two yellow pigments have been isolated. Aurasperone A, C32H26010, is obtained in yellow prisms; m. p. 207°C; [α]D-136°; gives the diacetate and the dimethyl ether and is assumed to be a dimeric 2-methyl-5-hydroxy-6, 8-dimethoxy-4H-naphtho [2, 3-b] pyran-4-one (IV). Aurasperone B, [α]D+46.3°, is the main yellow metabolite, m. p. 186°C, and affords aurasperone A on hydrochloric acid-treatment. It has molecular formula C32H30012 and is supposed to have the structure (V). The other yellow pigments have been found to be also congeners of aurasperone A.