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

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 P2 1 /c, with a = 9.663(4), b = 22.317(9), c = 7.747(5) Å, β = 113.03(4)°, D c = 1.496 g cm −3 , V = 1538(1) Å 3 , T = 25 °C, C 17 H 14 O 8 . 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.