-Hexitronic acid, a new tetronic acid derivative isolated from a soil fungus FG9RK.

A new tetronic acid derivative () together with terrestric acid (), a known metabolite of species, was isolated from the soil fungus, FG9RK following fermentation on solid rice medium. The structure of was elucidated by one- and two-dimensional NMR and MS measurements. The absolute configuration of the oxygenated carbon in the side chain of was identified as by converting the compound into its Mosher ester whereas the absolute configuration of the lactone ring was deduced based on biogenetic considerations and comparison with .