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EPC‐synthesis and fungistatic activity of a gloeosporone analog with an ω‐hydroxybutyl instead of the pentyl side chain on the macrocyclic ring
Author(s) -
Seebach Dieter,
Adam Geo,
von dem BusscheHünnefeld Christoph,
Gisi Ulrich,
Binder Heinz
Publication year - 1990
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1990199001182
Subject(s) - chemistry , side chain , stereochemistry , moiety , hemiacetal , intramolecular force , ring (chemistry) , enantiomer , acetylene , lactone , pyrone , organic chemistry , polymer
(+)‐5′‐Oxa‐gloeosporone ( 2 ), an analog of the natural germination self‐inhibitor (−)‐gloeosporone ( 1 ), is synthesized, largely following our previously published route to the parent compound. Thus, the hydroxybutyl side chain of 2 was introduced by hydroboration of a butenyl group (→ 14 ) which had been carried along throughout the synthesis up to the stage of the 14‐membered yne‐lactone 13 . Silyl protection (→ 15 ), oxidation of the acetylene to a 1,2‐diketone moiety (→ 16 ), and deprotection with spontaneous intramolecular hemiacetal formation completed the synthesis of (+)‐ 2 . The (+)‐oxa‐gloeosporone 2 exhibits an in vitro and in vivo antifungal activity spectrum with 14 microorganisms very similar to both the natural ( 1 ) and the unnatural enantiomer ( ent ‐ 1 ) of gloeosporone, indicating that neither the sense of chirality nor the side‐chain structure is important for the mode of action.