Carbon‐14 labelling of acarbose – a challenge over more than 20 yearsFiftieth Anniversary Special Issue, In Memoriam John Jones.

Acarbose is a potent α‐glucosidase inhibitor which is used successfully as a drug for the treatment of type II diabetes. The compound prevents enzymes of the α‐glucosidase group from cleaving carbohydrates. For the investigation of pharmacokinetics and drug metabolism a first carbon‐14 labelling synthesis was performed in 1981. According to the pharmaceutical production process, the radiosynthesis was performed by fermentation. Due to limited radiolytic stability, repeated radiosyntheses were necessary. Finally, carbon‐14 labelling was optimized to prepare [14C]acarbose on a gram scale with a significant increase of the radiochemical yield. The aspects of the fermentation over a period of about 20 years are described focussing the attention on the optimized radiosynthesis. Copyright © 2007 John Wiley & Sons, Ltd.