Synthesis of 18O-labelled alcohols from unlabelled alcohols

The synthesis of primary, secondary and tertiary O-18-enriched alcohols from readily available O-16-alcohols via a Mitsunobu esterification and hydrolysis is described. The method is further exemplified in the labelling of the active pharmaceutical ingredient, dropropizine and is shown to be tolerant of modern, separation friendly Mitsunobu reagents.