TEE FUNGUS Pithorwces chartarwn produces at least three depsipeptides, of which one, sporidesmolide III, is present only in small em-t.'
Sporideemolide III is a neutral compound, CT236 N 0 4 8, with absorption6 due to ester carbql (5.72~). amide I (5.95, 6.09 ~1, end amide II (6.45, 6.55~) in the infrared.
A vigorous acid bydrolysate, prepared and exsmined by paper chromatography in four different solvent systems , as described for sporidesmolide I' , contained
;raline (1.w mol.) and leucine (1.97 mol.); a-bydroxy-B-methylbutyric acid (c&. 2 mol.) was similarly identified in three different solvent systems.
A recent papsr2 described the rationalization of the mass spectra of the cyclohexadepsipeptides sporidesmolide I (A) and sporidesmolide II (B) in terms of their chemical structures. We now report an example of the application of this rationale which, when combined with the hydrolysis results, allowed the formulation of a unique structure for sporidesmolide III.
The mass spectrum of sporideamolide III (Fig. )" is very similar to the mass spectra of A and B2 except for differences which can be ascribed to sporidesmolide III having one less methyl group than A and two lees than B. * The figures in brackets placed after the m/e values in Fig. 1 and also in the text are the shifts which the peaks display in the mass spectrum of N-deuteriated sporidesmolide III prepared by exchange with D20.