Fast and efficient (18) F-labeling by [(18) f]fluorophenylazocarboxylic esters

Area of Science:

• Radiochemistry
• Organic Synthesis
• Nuclear Medicine

Background:

• Phenylazocarboxylic esters are versatile organic compounds.
• Efficient radiolabeling methods are crucial for developing diagnostic agents.
• Incorporating Fluorine-18 (18F) into organic molecules is challenging.

Purpose of the Study:

• To develop a rapid and efficient method for introducing 18F into the aromatic core of phenylazocarboxylic esters.
• To explore the utility of the resulting 18F-labeled compounds in further synthetic transformations.

Main Methods:

• Direct nucleophilic radiofluorination of phenylazocarboxylic esters using [18F]fluoride ion.
• Optimization of reaction time and conditions to maximize radiochemical yield.
• Subsequent conversion of the 18F-labeled azoester via radical-arylation and carbonyl substitution reactions.

Main Results:

• Achieved introduction of [18F]fluoride ion into the aromatic core of phenylazocarboxylic esters in only 30 seconds.
• Obtained high radiochemical yields up to 95% (85±10%).
• Demonstrated the successful conversion of the 18F-labeled azoester into biaryls and azocarboxamides.

Conclusions:

• A rapid and high-yielding method for 18F-labeling of phenylazocarboxylic esters was established.
• The 18F-labeled azoesters serve as valuable precursors for synthesizing diverse radiolabeled molecules.
• This method holds promise for the development of novel PET imaging agents.