A new intermediate in the degradation of carbofuran by Sphingomonas sp. strain SB5

Sphingomonas sp. strain SB5 could degrade carbofuran and carbofuran-7-phenol to a hydrolytic product, 2-hydroxy-3-(3-methlypropan-2-ol)phenol, and several red metabolites. However, the chemical structures of the red metabolites have largely remained unidentified. In this study, we identified the structure of one of the red metabolites as 5-(2-hydroxy-2-methyl-propyl)-2,2-dimethyl-2,3-dihydronaphtho[2,3-6] furan-4,6,7,9-tetrone by using mass spectrometric and NMR (¹H, ¹³C) analyses. It is suggested that the red metabolite resulted from condensation of some metabolites in the degradation of 2-hydroxy-3- (3-methlypropan-2-ol)phenol, a hydrolytic product derived from carbofuran. To our knowledge, this is the first paper to report a red metabolite in bacterial degradation of the insecticide carbofuran.