A direct fixation of CO2 for isotopic labelling of hydantoins using iodine-phosphine charge transfer complexes

Herein, we report a method for the isotopic labelling of hydantoins directly from CO2 by means of trimethyl-lambda(5)-phosphine diiodide mediated carbonyl insertion. The method is suitable for C-13-labelling of diverse substrates and was implementated for C-11-labelling in PET-imaging facilities for the synthesis of radiotracers. Isolated yields of 90% and radiochemical yields of 89% were achieved for hydantoin containing drug candidates in formulation within 30 min with high molar activity (>400 MBq nmol(-1)).

Automated summary

In this study, a method for isotopic labelling of hydantoins directly from CO2 was developed using trimethyl-lambda(5)-phosphine diiodide mediated carbonyl insertion. The method demonstrated high isolated yields and radiochemical yields, making it suitable for a wide range of substrates and for the synthesis of radiotracers in PET imaging facilities.