Isolation and biosynthesis of aurachin P and 5-nitroresorcinol from Stigmatella erecta

The isolation of aurachin P (2) from Stigmatella erecta strain Pd e32 is described. Spectroscopic data, in particular NMR data, indicate it is 1'-hydroxyaurachin A with a 1'R,2'S,3'R relative configuration. In addition, a further compound, 5-nitroresorcinol (4a), was isolated and identified as a novel natural product. Feeding of (13)C- and (15)N-labeled precursors indicated this was synthesized solely from glucose and ammonia. To account for the labeling pattern, phloroglucinol (8) is postulated as an intermediate branching off from 3-dehydroquinate (7) in the shikimate pathway.