A new 1-hydroxy-2,6-pyrazinedione associated with hypovirulent isolates of Sclerotinia minor.

A new 1-hydroxy-2,6-pyrazinedione, sclerominol (1), was isolated from cultures of hypovirulent isolates of Sclerotinia minor, a fungal plant pathogen associated with lettuce drop and other plant diseases. This compound was characterized by NMR, mass spectrometry, and X-ray crystallography. One other 1-hydroxy-2,6-pyrazinedione, flutimide, has been reported. Flutimide has activity as an inhibitor of influenza virus endonuclease, and therefore, sclerominol was evaluated for related biological activity. Sclerominol (1) displayed some activity against cancer cell lines but little activity against three influenza virus strains. The role of 1 in the physiology of hypovirulent isolates of S. minor has not been determined, but 1 has also been recovered from debilitated isolates of S. sclerotiorum.