No abstract

No abstract

No abstract

No abstract

The hydroxylamine nortryptoquivaline (2) and the three secondary amines deoxytryptoquivaline (3), deoxynortryptoquivaline (4), and deoxynortryptoquivalone (8) were found to be toxic metabolites of Aspergillus clauatus. They were accompanied by the two previously described tremor producing agents tryptoquivaline (1) and nortryptoquivalone (7). The only weakly basic secondary amines 3, 4, and 8 were oxidized to the corresponding hydroxylamines 1,2, and 7 with m-chloroperbenzoic acid.A strain of the fungus Aspergillus clavatus (NRRL-5890) collected from mold-damaged rice produced the two highly toxic, tremor inducing metabolites tryptoquivaline (1) and nortryptoquivalone (7).3 T h e p-bromophenylurethane of a transformation product of tryptoquivaline was utilized in the structure determination by x-ray crystallography while spectral data left little doubt t h a t n o r t r y p t o q~i v a l o n e~ has structure 7, but this conclusion remains to be confirmed by chemical correlation.More recently we had occasion t o examine another strain of Aspergillus clavatus (strain MIT-M-18) for the presence of mycotoxins. Its identity was established by the Centraalbureau voor Schimmelcultures, Baarn, The Netherlands. The fungus was one of several collected from mold-infested rice found in a Thai household where a child died of a n unidentified toxicosis.5 Solid substrate, agitated fermentation on pearled barley6 gave optimum yields of secondary metabolites and individual components were isolated by high-pressure liquid and thin layer chromatography. The least and most polar fractions contained the known fungal metabolites xanthocillin-X dimethyl ether (9)7 and kotanin (10): respectively.From the intermediate fractions nortryptoquivalone (7) and tryptoquivaline (1) could be isolated in crystalline form. These two metabolites were now found t o exhibit very similar circular dichroism spectra (see Experimental Section) tentatively suggesting identical relative configurations a t C2, C3, and c19.gThe least polar of the new metabolites, m p 256-258 "C, further characterized by its acetate 5, had the composition CzsHzsN407. Its ultraviolet absorption spectrum was indistinguishable from t h a t of tryptoquivaline (1) and all infrared absorptions associated with functional groups were identical in the two spectra. The proton magnetic resonance spectrum of the new metabolite was identical with t h a t of tryptoquivaline (1) except t h a t signals associated with t h e geminal dimethyl group in the latter were replaced by those of a secondary methyl function. The first of t h e new metabolites thus is nortryptoquivaline (2) and its circular dichroism spectrum indicates the relative stereochemistry shown. A second new metabolite, m p 150-152 OC, was found to have the composition C29H30N406. I t thus differs from tryptoquivaline (1) by the absence of an oxygen atom. The suggestion t h a t it might be deoxytryptoquivaline (3) was strengthened by a negative triphenyltetrazolium chloride test for hydroxylamines12 and confirmed by oxidation to...

Recent reports3-6 on the photoelimination of carbon dioxide from lactones and esters have prompted us to report our results that carbon dioxide extrusion is a general photochemical process for -phenyl-Y-butyrolactones (e.g., 1 and 2, Scheme I) and for their acyclic

No abstract

No abstract