Radiosynthesis and preclinical evaluation of [11C]prucalopride as a potential agonist PET ligand for the 5-HT4 receptor

EJNMMI Research

Table 1 Overview of parameters investigated to optimize radiosynthesis of [ ¹¹ C]prucalopride

Amount desmethyl prucalopride (μmol)	Base	Amount base (μmol)	Temp (°C)	Methylation agent	Yield (%)	Yield ^a	Number
3.0	NaOH	25.0	25	[¹¹C]CH₃I	0	Analytical	1
3.0	NaOH	25.0	85	[¹¹C]CH₃I	1	Analytical	1
3.0	NaOH	5.0	25	[¹¹C]CH₃I	6	Analytical	1
3.0	NaOH	5.0	85	[¹¹C]CH₃I	7	Analytical	1
2.2	TBAOH	5.1	25	[¹¹C]CH₃I	11 ± 1	Analytical	2
2.2	TBAOH	5.1	85	[¹¹C]CH₃I	12 ± 1	Analytical	2
3.0	TBAOH	6.9	85	[¹¹C]methyl triflate	12 ± 0	Analytical	2
2.2	TBAOH	4.4	85	[¹¹C]methyl triflate	16 ± 0	Preperative	2
3.5	TBAOH	5.3	85	[¹¹C]methyl triflate	31 ± 2	Preperative	2
2.2	TBAOH	3.5	85	[¹¹C]methyl triflate	32 ± 1	Preperative	2
2.7	TBAOH	4.3	85	[¹¹C]methyl triflate	34 ± 3	Preperative	14

For every reaction, CH₃CN was used as solvent; the reaction volume was 350 μL and the reaction time was 5 min. ^aThe presented yields are either determined by analysing samples taken from the crude reaction mixture (analytical yields) or determined from the activity at start of synthesis and the activity in the formulated product (preparative yields).