Structure and stereochemistry of cis-dihydro diol and phenol metabolites of bicyclic azaarenes from Pseudomonas putida UV4

Abstract

Biotransformation of quinoline, isoquinoline, quinoxaline and quinazoline using growing cultures of Pseudomonas putida UV4 yielded cis-dihydro diols from the oxidation of the carbocyclic aromatic ring. Aromatic hydroxylation was observed in both carbocyclic and heterocyclic rings. Ring cleavage of the quinoline skeleton to yield anthranilic acid, and cis-diol formation (with alkene bond reduction) to yield cis-5, 6, 7, 8-tetrahydroquinazoline-5, 6-diol from quinazoline were observed. The cis-dihydro diol metabolites of quinoline (5, 6- and 7, 8-) and quinoxaline (5, 6-) were found to be optically pure, while metabolism of isoquinoline gave one homochiral (5, 6-) and one racemic (7, 8-)cis-dihydro diol product. The absolute configurations of the cis-dihydro diol metabolites have been determined using 1H NMR analyses, stereochemical correlations and X-ray crystallography methods.