Isolation of 2-Alkyl-4-quinolones with Unusual Side Chains from a Chinese Isolate.

Chemical investigation of a strain isolated from Hebei, China, led to the isolation of a suite of quinolones, quinolone--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 -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.