Synthesis of morphine 6-α-d-glucuronide

This paper provides the first report on stereoselective synthesis and characterization of morphine 6-α-d-glucuronide (M6αG), useful as a reference marker for testing the purity and stability of the pharmaceutically important morphine 6-β-d-glucuronide (M6G). The synthesis is based on the glycosylation of 3-O-acetylated morphine with methyl 2,3,4-tri-O-acetyl-d-glucopyranosyluronate bromide as glycosyl donor and zinc bromide as catalyst. Furthermore, we showed that the α/β stereoselectivity of the reaction can be directed and controlled by the amount of zinc bromide.