Phenalenones and polyesters from Talaromyces stipitatus and structure revision of talaromycesone A

Investigation of the secondary metabolites of the filamentous fungus Talaromyces stipitatus led to the isolation of two new phenalenone dimers, talarohemiketal A (1) and talaroazasone A (2), and one new macrolide polyester, talaromacrolactone A (3), along with the reported oxyphenalenone dimers talaromycesone A (4), bacillisporin A (5), bacillisporin B (6), bacillisporin C (7), epi-bacillisporin F (8), and bacillisporin J (9), the phenalenone monomer funalenone (10), the polyesters 15G256α (11) and 15G256ν (12), and 6-hydroxymellein (13). Detailed analysis of 2D NMR correlations, supported by TDDFT calculations, led to the structural revision of talaromycesone A as 4 from previously reported structure 14. In addition, the previously misassigned NMR spectra of compound 8 have been corrected.