Synthesis and in vitro evaluation of 5-substituted benzovesamicol analogs containing N-substituted amides as potential positron emission tomography tracers for the vesicular acetylcholine transporter

The development of 11C-carbonylation chemistry: A systematic view

The prospects for using carbon-11 labelled compounds in molecular imaging has improved with the development of diverse synthesis methods, including 11C-carbonylations and refined techniques to handle [11C]carbon monoxide at a nanomole scale. Facilitating biological research and molecular imaging was the driving force when [11C]carbon monoxide was used in the first in vivo application with carbon-11 in human (1945) and when [11C]carbon monoxide was used for the first time as a chemical reagent in the synthesis of [11C]phosgene (1978). This review examines a rich plethora of labelled compounds synthesized from [11C]carbon monoxide, their chemistry and use in molecular imaging. While the strong development of the 11C-carbonylation chemistry has expanded the carbon-11 domain considerably, it could be argued that the number of 11C-carbonyl compounds entering biological investigations should be higher. The reason for this may partly be the lack of commercially available synthesis instruments designed for 11C-carbonylations. But as this review shows, novel and greatly simplified methods to handle [11C]carbon monoxide have been developed. The next important challenge is to make full use of these technologies and synthesis methods in PET research. When there is a PET-tracer that meets a more general need, the incentive to implement 11C-carbonylation protocols will increase.

Contilisant, a Tetratarget Small Molecule for Alzheimer's Disease Therapy Combining Cholinesterase, Monoamine Oxidase Inhibition, and H3R Antagonism with S1R Agonism Profile

Contilisant, a permeable, antioxidant, and neuroprotectant agent, showing high nM affinity at H3R and excellent inhibition of the monoamine oxidases and cholinesterases, is an affine and selective S1R agonist in the nanomolar range, based on the binding affinity and functional experiment, a result confirmed by molecular modeling. In addition, contilisant significantly restores the cognitive deficit induced by Aβ1-42 in the radial maze assay in an in vivo Alzheimer's disease test, comparing very favorably with donepezil.

Synthesis of 11C-Labelled Ureas by Palladium(II)-Mediated Oxidative Carbonylation

Positron emission tomography is an imaging technique with applications in clinical settings as well as in basic research for the study of biological processes. A PET tracer, a biologically active molecule where a positron-emitting radioisotope such as carbon-11 has been incorporated, is used for the studies. Development of robust methods for incorporation of the radioisotope is therefore of the utmost importance. The urea functional group is present in many biologically active compounds and is thus an attractive target for incorporation of carbon-11 in the form of [¹¹C]carbon monoxide. Starting with amines and [¹¹C]carbon monoxide, both symmetrical and unsymmetrical ¹¹C-labelled ureas were synthesised via a palladium(II)-mediated oxidative carbonylation and obtained in decay-corrected radiochemical yields up to 65%. The added advantage of using [¹¹C]carbon monoxide was shown by the molar activity obtained for an inhibitor of soluble epoxide hydrolase (247 GBq/μmol–319 GBq/μmol). DFT calculations were found to support a reaction mechanism proceeding through an ¹¹C-labelled isocyanate intermediate.