Authors:  Coralie M. Bonnemaire1, Albert D. Windhorst1, Jurriën W. Collet2, Eelco Ruijter2, Romano V. A. Orru2, Danielle J. Vugts1
1 Amsterdam UMC, Vrije Universiteit Amsterdam, Radiology & Nuclear Medicine(s), Amsterdam Institute of Molecular and Life Sciences (AIMMS), de Boelelaan 1117, Amsterdam, Netherlands
2 Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
Background
The radiochemists’ synthetic possibilities are limited, due to a lack of variation in building blocks for PET tracer synthesis. N-formamides are important building blocks for the synthesis of a large variety of biological active compounds1. As such they are also interesting for PET tracer synthesis upon labelling with carbon-11.
Aims
The aim was to develop a fast and easy synthesis method for 11C-labelled N-formamides and apply this in the synthesis of the long-acting β2 agonist: N-[formyl-11C]formoterol2.
Methods
11C-labelled N-formamides were prepared in one-pot starting by reduction of cyclotron produced [11C]CO2 to [11C]formic acid3, followed by N-11C-formylation of an amine. The N-11C-formylation reaction was achieved using the coupling agent BOP in pyridine. The synthesis route was developed using benzylamine as model substrate and was extended to other amines.
Results and Conclusion
N-[formyl-11C]benzylformamide could be isolated in 40±9% radiochemical yield, with 87±10% radiochemical purity and a molar activity higher than 100GBq/µmol in less than 26 min from EOB (n=3). A small series of 11C-labelled N-formamides was obtained with similar yields. This method will now be applied in the synthesis of N-[formyl-11C]formoterol.