The constitution of vertinolide,a new derivative of tetronic acid,produced by Verticillium intertextum

From the culture of Verticillium intertextrum a new tetronic acid derivative, vertinolide, has been isolated as the main constituent of the chloroform extract. Structure 1a was established for vertinolide by X-ray diffraction analysis. Vertinolide (1a) was also transformed to an O-methyl-(1b), an O-acetyl-(1c), a tetrahydro- (1d) and a tetrahydro-O-methyl-derivative (4). The spectroscopic properties of 1a, of its derivatives 1a, 1c, 1d and 4 as well as of three model compounds are compared and discussed.