Taichunamides: Prenylated Indole Alkaloids from Aspergillus taichungensis (IBT 19404)

• Published in: Angewandte Chemie (International ed.) Vol. 55; no. 3; pp. 1128 - 1132
• Main Authors: Kagiyama, Ippei, Kato, Hikaru, Nehira, Tatsuo, Frisvad, Jens C., Sherman, David H., Williams, Robert M., Tsukamoto, Sachiko
• Format: Journal Article
• Language: English
• Published: WEINHEIM Blackwell Publishing Ltd 18.01.2016; Wiley; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Alkaloids; Aspergillus; Aspergillus - chemistry; biosynthesis; Chemistry; Chemistry, Multidisciplinary; Congeners; Cores; cycloaddition; Fungi; Indole Alkaloids - chemistry; Indole Alkaloids - isolation & purification; Indoles; natural products; Physical Sciences; Prenylation; Science & Technology; structure elucidation; USTUS; natural products; cycloaddition; alkaloids; biosynthesis; PARAHERQUAMIDE; PENICILLIUM-SIMPLICISSIMUM AK-40; MARINE-DERIVED FUNGUS; structure elucidation; MALBRANCHEAMIDE
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201509462

Seven new prenylated indole alkaloids, taichunamides A–G, were isolated from the fungus Aspergillus taichungensis (IBT 19404). Taichunamides A and B contained an azetidine and 4‐pyridone units, respectively, and are likely biosynthesized from notoamide S via (+)‐6‐epi‐stephacidin A. Taichunamides C and D contain endoperoxide and methylsulfonyl units, respectively. This fungus produced indole alkaloids containing an anti‐bicyclo[2.2.2]diazaoctane core, whereas A. protuberus and A. amoenus produced congeners with a syn‐bicyclo[2.2.2]diazaoctane core. Plausible biosynthetic pathways to access these cores within the three species likely arise from an intramolecular hetero Diels–Alder reaction. Magnificent seven: Seven new prenylated indole alkaloids were isolated from A. taichungensis. This fungus produces alkaloids containing an anti‐bicyclo[2.2.2]diazaoctane core, whereas A. protuberus and A. amoenus produce derivatives with a syn‐bicyclo core. The structural diversity of tryptophan‐derived secondary metabolites reveals unusually diverse stereochemical and structural secondary metabolite tailoring functions in these orthologous fungi.