Isokotanins A-C: new bicoumarins from the sclerotia of Aspergillus alliaceus.
Three new bicoumarin metabolites, isokotanins A [1], B [2], and C [3], were isolated from the sclerotia of Aspergillus alliaceus. Isokotanin A is a regioisomer of the known bicoumarin kotanin [4]. The structures and spectral assignments for 1-3 were determined on the basis of selective INEPT, HMQC, and NOESY nmr data, as well as by chemical interconversions. Isokotanins B and C show activity against the corn earworm Helicoverpa zea and the dried fruit bettle Carpophilus hemipterus. The known compounds kotanin [4], desmethylkotanin [5], nominine, and paspaline were also isolated from extracts of A. alliaceus sclerotia.
Laakso
J A
JA
Department of Chemistry, University of Iowa, Iowa City, 52242.
Narske
E D
ED
Gloer
J B
JB
Wicklow
D T
DT
Dowd
P F
PF
D000818:Animals; D001230:Aspergillus / Q000737:chemistry*; D003374:Coumarins / Q000302:isolation & purification* / Q000633:toxicity; D007313:Insecta; D007306:Insecticides / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy
D003374:Coumarins; D007306:Insecticides; C086778:isokatanin A; C086781:isokatanin B; C086782:isokatanin C