Rapid microfluidic flow hydrogenation for reduction or deprotection of 18F-labeled compounds

Area of Science:

• Radiochemistry
• Organic Synthesis
• Chemical Engineering

Background:

• Positron Emission Tomography (PET) imaging requires efficient synthesis of radiolabeled compounds.
• Traditional methods for reduction and protecting group manipulation can be time-consuming.
• Microfluidics and flow chemistry offer advantages in reaction control and speed.

Purpose of the Study:

• To integrate microfluidics with flow hydrogenation for novel synthetic applications.
• To explore underutilized reduction and protecting group chemistries for PET imaging.
• To demonstrate rapid synthesis of key PET precursors.

Main Methods:

• Utilized a microfluidic device integrated with a flow hydrogenation system.
• Applied the system to O-benzyl protecting group removal.
• Applied the system to nitro group reduction.

Main Results:

• Achieved rapid O-benzyl deprotection to synthesize 2-[(18)F]fluoroquinolin-8-ol.
• Successfully reduced a nitro group to synthesize 4-[(18)F]fluoroaniline.
• Both reactions were completed within a 3-minute timeframe.

Conclusions:

• The combined microfluidics and flow hydrogenation approach provides facile access to important PET precursors.
• This method significantly reduces reaction times for key synthetic steps.
• It expands the utility of reduction and protecting group chemistry in radiopharmaceutical synthesis.