Pyrones. X. Lateropyrone, a new antibiotic from the fungus Fusariumlateritium Nees

Abstract

Lateropyrone, 5-hydroxy-9-methoxy-2-methyl-4H,6H-pyrano[3,4-g]-1-benzopyran-4,6-dione-8-carboxylic acid, 1, has been isolated from cultures of the fungus Fusariumlateritium Nees, and shown to have inhibitory activity against the growth of a gram-positive bacterium and a yeast. A crystal structure of the dimethyl derivative of lateropyrone, 2, was determined. The crystals are monoclinic, space group P21/c, with a = 9.663(4), b = 22.317(9), c = 7.747(5) Å, β = 113.03(4)°, Dc = 1.496 g cm−3, V = 1538(1) Å3, T = 25 °C, C17H14O8. The structure was refined to R = 0.0543 by least squares using 2100 observed, independent reflections measured on a 4-circle diffractometer, to obtain 241 parameters. The linearly fused tricyclic ring system is only approximately planar. In- and out-of-plane distortions are rationalized in terms of molecular overcrowding.