Chemosphere, Vol.16, No.7, pp 1381-1386, 1987 0045-6535/87 $3.O0 + .00 Printed in Great Britain Pergamon Journals Ltd. SYNTHESIS AND 13C NMR ANALYSIS OF SOME XENOBIOTIC CONJUGATES Jocelyne Hellou, Joseph H. Banoub and Howard J. Hodder Science Branch Department of Fisheries and Oceans P.O. Box 5667 St. John's, Newfoundland Canada AIC 5XI Abstract The synthesis of several aromatic and aliphatic n-alkyl glucuronides was accomplished by the stannic chloride catalyzed O-glycosylation method. The 13C NMR spectra of the synthetic glucuronides were compa~d to that of the glucuronides isolated from the gall-bladder bile of fish exposed to No. 2 fuel oil. Introduction Exposure of various vertebrates to organic pollutants leads to metabolic transformations of these chemicals, allowing their elimination from the organism, via the gall-bladder I. This process begins with enzymatic oxidation or reduction catalyzed by mixed function oxygenaseenzymes, and the free metabolites produced are then conjugated to amino acids, glutathione, sulfate groups or glucuronic acid. This renders these foreign compounds more water-soluble and more capable of excretion 2. The authors have shown 3 that upon exposure of cunners, Tautogolabrus adspersus, to water accommodatedNo. 2 fuel oil, a mixture of conjugated metabolites was isolated from the gall-bladder bile of these fish. Analysis of these xenobiotic metabolites by 13C NMR allowed the identification of B- glucuronides enriched in aromatic vs aliphatic carbons, when compared to the petroleum mixture. We postulated that in the isolated ~-glucuronides, the glycosidic oxygen at the anomeric carbon atom C-I of the glucuronic acid moiety was attached to an aliphatic carbon atom of a chain belonging to the aglyconic aromatic molecules. In view of the absence of any signals, other than those due to the sugar moiety, between 50 and 80 ppm, it was also suggested that the anomeric carbon atom C-I was attached to an oxygen atom of a secondary or tertiary alcohol. The synthesis of various glucuronides, from methyl-l,2,3,4-tetra-O-acetyl-~-D-glucuronate and several primary and secondary alcohols by the Lewis acid [stannic chloride] catalyzed O-glycosylation method 4'5'6, was undertaken in order to compare the chemical shift of the anomeric carbon atom C-I and that of the aglyconic aliphatic carbon atom C-I' attached to the glycosidic oxygen with similar carbon atoms in the metabolites isolated from fish. V. J. Feil has recently reviewed the xenobiotic conjugates identified with the help of 13C and IH NMR and pointed to the lack of appropriate synthetic model compounds in the literature 7. 1381