New Synthesis of Phenolphthalein β-Glucuronide

Abstract

Convenient synthesis of phenolphthalein β-glucuronide (IV), which is widely used for the assay of β-glucuronidase activity as a substrate, has been described. Koenigs-Knorr reaction of phenolphthalin methyl ester (I) with methyl acetobromoglucuronate in the presence of cadmium carbonate as a catalyst provided the monoglucuronide acetatemethyl ester (II) which on oxidation with 2, 3-dichloro-5, 6-dicyanobenzoquinone was led to the phenolphthalein derivative (III). Elimination of protecting groups with methanolic sodium hydroxide afforded the desired compound (IV) in a satisfactory yield.