Synthesis and analysis of glucuronides of N-hydroxyamides

Reactions of five N-hydroxyacetylarylamines (N-hydroxyphenacetin, N-hydroxyacetanilide, N-hydroxy-p-chloroacetanilide, N-hydroxy-2-acetylaminonaphthalene, and N-hydroxy-2-acetylaminofluorene) with uridine 5'-diphosphoglucuronic acid catalyzed by immobilized glucuronyl transferase enzyme resulted in the formation of glucuronides conjugated at the N-hydroxyl group. Chromatographic properties of these compounds were examined by using thin layer, gas liquid, and high pressure liquid chromatography. A variety of mass spectrometric techniques were also evaluated for characterization of compounds of this class, including fast atom bombardment, chemical ionization, and electron impact. Electron impact spectra of the trimethylsilyl derivatives contain class characteristic ions and fragmentation pathways that would permit the special nature of the site of conjugation of this important class of compounds to be recognized in glucuronides of undetermined structure. Molecular ion species were not reliably detected in the electron impact spectra; however, these were readily distinguishable by the other two techniques.