The structures of three metabolites from a strain of Aspergillus flavipes were investigated, including a previously reported antibiotic termed 'glutamicine' (C₁₂H₁₅NO₄) with the proposed structure 3-acetyl-4-isovaleryl-6-hydroxy-2(1H)-pyridone by Casinovi et al. Through large-scale fermentation, approximately 1 g of the antibiotic was obtained for detailed analysis. Spectroscopic (n.m.r., i.r., U.V.) data and chemical results demonstrated the incompatibility of the proposed structure. Instead, evidence supports the novel structure 3'-isovaleryl-6-methylpyridine-3-spiro-2'-oxiran-2(1H),4(3H)-dione (1), named flavipucine. Chromatography of chloroform extracts from Aspergillus flavipes yielded terreic acid (2) and flavipucine, which was identical to the prior 'glutamicine' material. Purification revealed a 20-25% impurity (5), an isomer of flavipucine. N.m.r. and double resonance techniques showed that the signal formerly ascribed to an acetyl group is coupled with a vinylic proton, which is incompatible with an acetyl group but consistent with the structural feature *CMe:CH* in (1). Spectroscopic evidence confirmed the presence of a methyloxobutyl side-chain. Reduction of flavipucine with lithium aluminium hydride produced 2-methyl-5-(2-hydroxy-4-methylpentyl)pyridine (3a), confirming the 2,5-substitution pattern. The catalytic reduction product was identified as a tetrahydrodeoxyderivative (4), formulated as 4-hydroxy-3-(2-hydroxy-4-methylpentyl)-6-methyl-2(1H)-pyridone. I.r. data supported the presence of a lactam in flavipucine. The alternate structure (6) for the antibiotic was excluded based on n.m.r. comparisons with appropriate 2,5-disubstituted pyridines. Synthetic studies to confirm these findings are currently in progress.