Isolation of 2‑Alkyl-4-quinolones with Unusual Side Chains from a Chinese Pseudomonas aeruginosa Isolate

Chemical investigation of a Pseudomonas aeruginosa strain isolated from Hebei, China, led to the isolation of a suite of quinolones, quinolone-N-oxides, and phenazines, the structures of which were elucidated by detailed spectroscopic analysis. Most notable among the secondary metabolites isolated was an unprecedented 4-quinolone containing an S-methyl group in the side chain and a new derivative including a phenyl ring in the side chain, which expand significantly the variety of structural motifs found in the quinolones and raise interesting questions about their biosynthesis.