Chaetochromins B, C and D, bis(naphtho-.GAMMA.-pyrone) derivatives from Chaetomium gracile.

Abstract

Besides chaetochromin A (1), a known mycotoxin and antitumor agent, three related bis(naphtho-.gamma.-pyrone) derivatives chaetochromins B (2), C (3), and D (4) were isolated from Chaetomium gracile. The structures were elucidated as the diastereomer, the 3-demethyl derivative, and the 2,3-dehydro derivative of 1, respectively, chiefly on the basis of nuclear magnetic resonance data.