Selective synthesis of racemic 1-11C-labelled norepinephrine, octopamine, norphenylephrine and phenylethanolamine using [11C]nitromethane

Norepinephrine is the predominant neurotransmitter of the sympathetic innervation of the heart. Racemic norepinephrine was labelled with carbon-ll and injected i.v. into Cynomolgus monkeys. Five minutes after injection there was a more than tenfold higher radioactivity in the heart than in adjacent tissue. Pretreatment with the norepinephrine reuptake inhibitor desipramine reduced the uptake by more than 80%. The high specific uptake of racemic [l~C]norepinephrine indicates that enatiomerically pure (-)-[l~C]norepinephrine has promising potential for detailed mapping of the sympathetic innervation of the human myocardium.

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“…Racemic [l~C]norepinephrine was prepared with high specific radioactivity (>1000 Ci/mmol) from [l~C]nitromethane [9].…”

Section: Methodsmentioning

confidence: 99%

Positron emission tomography shows high specific uptake of racemic carbon-11 labelled norepinephrine in the primate heart

et al. 1994

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“…The second strategy involving [ 11 C]CH 3 NO 2 , instead, requires the two hydroxyl groups to be protected as dioxole. [ 11 C]CH 3 NO 2 reacts with a 3 , 4 -methylenedioxybenzaldehyde in the presence of TBAF, forming a [ β - 11 C] 3 , 4 -(methylenedioxy)- β -nitrophenetyl alcohol, which was subsequently reduced using Raney nickel and formic acid and deprotected with BH 3 (Figure B) . [ 11 C]Norepinephrine was synthesized with an isolated RCY of 20–25% at the end of [ 11 C]CH 3 NO 2 synthesis and A m of 26–56 GBq/μmol with a total processing time of 65–70 min …”

Section: Hormones and Neurotransmittersmentioning

confidence: 99%

“…Figure 146. Synthesis of D,L-p-[1-11 C]octopamine from [ 11 C]CH 3 NO 2 685. 11 C radionuclide position is highlighted in red.…”

mentioning

confidence: 99%

Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds

et al. 2022

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The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades, methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects.

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“…Several neurotransmitters and their precursors have been studied including 11 C L-tyrosine(41), L-DOPA(77), L-tryptophan(31), 5-hydroxy-L-tryptophan(31), 11 C epinephrine(78) and 11 C norepinephrine(79). 11 C epinephrine has been used to study cardiac sympathetic nerve function in the context of heart transplantation, since the latter is associated with decreased sympathetic nerve integrity(80).…”

Section: Neurotransmittersmentioning

confidence: 99%

Exploring Metabolism In Vivo Using Endogenous 11 C Metabolic Tracers

Neumann

Flavell

Wilson

2017

Seminars in Nuclear Medicine

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Cancer and other diseases are increasingly understood in terms of their metabolic disturbances. This thinking has revolutionized the field of ex vivo metabolomics and motivated new approaches to detect metabolites in living systems including proton magnetic resonance spectroscopy (1H-MRS), hyperpolarized 13C MRS, and positron emission tomography (PET). For PET, imaging abnormal metabolism in vivo is hardly new. Positron-labeled small-molecule metabolites have been used for decades in humans, including 18F-FDG, which is used frequently to detect upregulated glycolysis in tumors. Many current 18F metabolic tracers including 18F-FDG have evolved from their 11C counterparts, chemically identical to endogenous substrates and thus approximating intrinsic biochemical pathways. This mimicry has stimulated the development of new radiochemical methods to incorporate 11C and inspired the synthesis of a large number of 11C endogenous radiotracers. This is in spite of the 20-minute half-life of 11C, which generally limits its use in patients to centers with an on-site cyclotron. Innovation in 11C chemistry has persisted in the face of this limitation, because (1) the radiochemists involved are inspired (2) the methods of 11C incorporation are diverse and (3) 11C compounds often show more predictable in vivo behavior, thus representing an important first step in the validation of new tracer concepts. In this mini-review we will discuss some of the general motivations behind PET tracers, rationales for the use of 11C, and some of the special challenges encountered in the synthesis of 11C endogenous compounds. Most importantly, we will try to highlight the exceptional creativity employed in early 11C tracer syntheses, which used enzyme-catalyzed and other “green” methods before these concepts were commonplace.

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Selective synthesis of racemic 1-11C-labelled norepinephrine, octopamine, norphenylephrine and phenylethanolamine using [11C]nitromethane

Cited by 22 publications

References 26 publications

Positron emission tomography shows high specific uptake of racemic carbon-11 labelled norepinephrine in the primate heart

Positron emission tomography shows high specific uptake of racemic carbon-11 labelled norepinephrine in the primate heart

Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds

Exploring Metabolism In Vivo Using Endogenous 11 C Metabolic Tracers

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