Acyl glucuronides

Carbohydrate derivatives containing glucuronic acid linked to another substance through an ester bond attached at position C-1, C-2, C-3, or C-4 of the glucuronic acid moiety. The C-1 acyl glucuronide is usually the initial isomer, However, the acyl group can rearrange from its initial position on the C-1 hydroxyl group of the glucuronic acid moiety to the C-2 and, subsequently, the C-3 and the C-4 hydroxyl group. Formation of the C-3 from the C-2 isomer, and the C-4 from the C-3 isomer is possible, whereas the C-1 isomer cannot result from the other regioisomers via acyl migration.