1-Bromo-1-deoxy-α-L-idopyranuronic Acid Methyl Ester Triacetate is a proposed intermediate in the synthesis of 4-Methylumbelliferyl α-L-Iduronide (free acid) (M337643), a fluorogenic substrate for α-L-iduronidase. This product form is the free acid, which offers a considerable weight for weight advantage over the 4-MU iduronide salt in terms of its application dose.