A Simple, Rapid Method for the Preparation of [¹¹C]Formaldehyde

Abstract

A PET project: A powerful reagent for the synthesis of positron‐emitting imaging molecules—[11C]formaldehyde—is accessible from [11C]methyl iodide and trimethylamine N‐oxide (TMAO) in high yields and under mild conditions. Easy access to [11C]formaldehyde expands the scope of the carbon‐11 toolbox and will lead to new reaction methodology and imaging compounds.

A fast chemoenzymatic synthesis of [11C]-N5,N10-methylenetetrahydrofolate as a potential PET tracer for proliferating cells

“…2, about 70% of the reaction was completed within 60 sec. In the next min, the yield of the product 14 CH 2 H 4 folate was observed up to 80%, and there was no substantial increase in the yield after that, which is in accordance with ref [3]. Therefore, we chose 2 min reaction time for the conversion of 11 CH 3 I to 11 CH 2 O when synthesizing of 11 CH 2 H 4 folate.…”

“…The incorporation of 11 C into small molecules has been important to the success of PET for in vivo molecular imaging and drug research and development [2]. The short half-life (t 1/2 = 20.38 min), allows for repeated studies within a short time span, but requires rapid chemical syntheses and purifications [3]. …”

“…In this communication, we describe the synthesis of 11 CH 2 H 4 folate by combining two fast and high yielding methods, i.e., a simple and fast method for the synthesis of [ 11 C]-formaldehyde ( 11 CH 2 O), reported by Hooker et al[3], with an equally efficient chemo-enzymatic method for the preparation of CH 2 H 4 folate from folic acid as reported earlier by our laboratory [16, 19]. …”

Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging

“…Methods are available for preparing a myriad of other secondary labeling agents of as yet less utility and popularity than those mentioned above, including [ 11 C]formaldehyde [350, 351], higher [ 11 C]alkyl halides [352, 353], [ 11 C]nitroalkanes [354], [ 11 C]acetone [355], [ 11 C]phosgene [356–359], and [ 11 C]benzyl halides [360–362]. Readers are directed to the pertinent literature [350–362] for more details on such methods.…”

Novel Positron Emission Tomography Tracer Distinguishes Normal from Cancerous Cells

“…PET imaging requires positron-emitting radioisotopes, such as oxygen ( 14 O, 15 O) (7,8) nitrogen ( 13 N) (9), fluorine-18 ( 18 F) (10 -12), and carbon ( 11 C) (13)(14)(15), incorporated into pharmaceutical probes to observe selective accumulation in a tissue of interest (16,17). Two of the most extensively used PET probes for cancer are [ 18 F]fluorodeoxyglucose (18 -20) and [ 18 F]fluorothymidine (21)(22)(23)(24).…”