Fonsecin, a Naphthopyrone Pigment from a Mutant of Aspergillus fonsecaeus

Abstract

IN 1953 Raper and Fennell¹ described an ultraviolet mutant of Aspergillus fonaecaeus (N.R.R.L. 67), which was characterized by a rich deposit of yellow pigment in the vesicles and primary sterigmata. We became interested in this material as a possible precursor of the brown and black pigments of the parent strain and, accordingly, isolated the crude pigment by ethyl acetate extraction of the dried mycelial mat. Fractional precipitation and recrystal-lization from ethyl acetate–petroleum ether mixtures gave a pure substance in the form of bright yellow irregular prisms (m.p. 198° decomposition) to which the name fonsecin was assigned. δ_max (ethanol) 233, 275, 321, 332, and 400 mµ (ɛ, 26,400; 31,400; 7,300; 8,025; and 8,775, respectively). (Found: C, 62.3; 62.1; H, 4.94; 4.79; OCH₃, 11.4; CH₃, 6.2. C₁₅H₁₂O₅.-H₂O requires: C, 62.06; H, 4.82; 1 OCH₃, 10.7; 1 CH₃, 5.2.)