Structural elucidation of the nigerones, four new naphthopyrones from cultures of Aspergillus niger

Abstract

The isolation and structure of four new pigments, nigerone (la), 6′-O-demethylnigerone (1b), isonigerone (2), and heminigerone (3), are described. A study of the chiroptical properties of the dimers indicates the S-configuration.