Pseudopyronines A and B, α-pyrones produced by a marine Pseudomonas sp F92S91, and evidence for the conversion of 4-hydroxy-α-pyrone to 3-furanone

In our search for inhibitors of bacterial fatty acid biosynthesis, two new alpha-pyrones, pseudopyronines A (1) and B (2), were isolated from a marine Pseudomonas sp. F92S91. The naturally occurring a-pyrones appeared to be unstable, evidenced by the conversion of pseudopyronine B into an oxidation product, 3-furanone (3). Structural elucidations were made by spectroscopic analyses including 2D-NMR data.