Radiosynthesis and Evaluation of an 18F-Labeled Positron Emission Tomography (PET) Radioligand for Brain Histamine Subtype-3 Receptors Based on a Nonimidazole 2-Aminoethylbenzofuran Chemotype
摘要:
A known chemotype of H-3 receptor ligand was explored for development of a radioligand for imaging brain histamine subtype 3 (H-3) receptors in vivo with positron emission tomography (PET), namely nonimidazole 2-aminoethylbenzofurans, represented by the compound (R)-(2-(2-(2-methylpyrrolidin-1-yl)ethyl)benzofuran-5-yl)(4-fluorophenyl)-methanone (9). Compound 9 was labeled with fluorine-18 (t(1/2) = 109.7 min) in high specific activity by treating the prepared nitro analogue (12) with cyclotron-produced [F-18]-fluoride ion. [F-18]9 was studied with PET in mouse and in monkey after intravenous injection. [F-18]9 showed favorable properties as a candidate PET radioligand, including moderately high brain uptake with a high proportion of H-3 receptor-specific signal in the absence of radiodefluorination. The nitro compound 12 was found to have even higher H-3 receptor affinity, indicating the potential of this chemotype for the development of further promising PET ralioligands.
Radiosynthesis and Evaluation of an 18F-Labeled Positron Emission Tomography (PET) Radioligand for Brain Histamine Subtype-3 Receptors Based on a Nonimidazole 2-Aminoethylbenzofuran Chemotype
摘要:
A known chemotype of H-3 receptor ligand was explored for development of a radioligand for imaging brain histamine subtype 3 (H-3) receptors in vivo with positron emission tomography (PET), namely nonimidazole 2-aminoethylbenzofurans, represented by the compound (R)-(2-(2-(2-methylpyrrolidin-1-yl)ethyl)benzofuran-5-yl)(4-fluorophenyl)-methanone (9). Compound 9 was labeled with fluorine-18 (t(1/2) = 109.7 min) in high specific activity by treating the prepared nitro analogue (12) with cyclotron-produced [F-18]-fluoride ion. [F-18]9 was studied with PET in mouse and in monkey after intravenous injection. [F-18]9 showed favorable properties as a candidate PET radioligand, including moderately high brain uptake with a high proportion of H-3 receptor-specific signal in the absence of radiodefluorination. The nitro compound 12 was found to have even higher H-3 receptor affinity, indicating the potential of this chemotype for the development of further promising PET ralioligands.