Convenient syntheses of the in vivo carbohydrate metabolites of mycophenolic acid: reactivity of the acyl glucuronide

We report effective preparations of the O-aryl glucuronide 2 and glucoside 4, as well as the O-acyl glucuronide 3, of the immunosuppressant agent mycophenolic acid 1. Heavy metals are avoided in the preparations of 2 and 4 and a careful optimisation of the synthesis of 3 is detailed. Finally we confirm the value of synthetic 3 by comparing its reactivity with that of a biosynthesised sample against a known target protein.