Selective synthesis of both isomers of morphine 6-β-d-glucuronide and their analogs

A stereoselective synthesis of both isomers of the pharmaceutically important morphine 6-β-d-glucuronide (M6G) and its analogs was developed. The method is based on the use of ZnBr2 for the key coupling reaction. It was shown that the α/β stereoselectivity of the reaction can be directed and controlled by the amount of ZnBr2. This paper describes the synthesis, analysis and characterization of the α-isomer of M6G, useful as a reference marker for testing purity and stability of the morphine 6-β-d-glucuronide (M6G).