Chaephilones A and B, Two New Azaphilone Derivatives Isolated from Chaetomium globosum

Two new azaphilone derivatives, chaephilones A ( 1 ) and B ( 2 ), were isolated from the fungus Chaetomium globosum , together with four structurally related analogs 3  –  6 . The structures of 1 and 2 were elucidated by comprehensive spectroscopic analyses including HR ‐ ESI ‐ MS and NMR . The known compounds were identified as chaetomugilin Q ( 3 ), chaetomugilin D ( 4 ), 11‐epichaetomugilin A ( 5 ), and chaetomugilin S ( 6 ) by comparing their NMR data and optical rotation values with those reported. Compound 2 represents the first example of azaphilone with an open furan ring. Compounds 1 and 2 were evaluated for cytotoxic activities against five human cancer cell lines ( HL ‐60, SMMC ‐7721, A‐549, MCF ‐7, and SW 480) by the MTS method.