Studies on fungal products. XVIII. Isolation and structures of a new fungal depsidone related to nidulin and a new phthalide from Emericella unguis.

Two new compounds, 2-chlorounguinol (1), C19H17ClO5, and 3-ethyl-5, 7-dihydroxy-3, 6-dimethylphthalide (5), C12H14O4, were isolated from the dichloromethane extract of culture filtrate of Emericella unguis (anamorph : Aspergillus unguis), together with nidulin (2) and unguinol (4). The structure of 2-chlorounguinol (1) was determined on the basis of spectroscopic investigations and X-ray crystallography, and that of the phthalide (5) was confirmed by spectroscopic investigations of several derivatives. 2-Chlorounguinol (1) is a fungal depsidone related to nidulin (2), originally isolated from E. nidulans. This is the first example of the isolation of a 3, 3-disubstituted phthalide as a naturally occurring compound.