A simple synthesis of [11C]methyl triflate

doi:10.1016/0883-2889(92)90012-4

International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes

Volume 43, Issue 11, November 1992, Pages 1383-1385

https://doi.org/10.1016/0883-2889(92)90012-4 Get rights and content

Abstract

[¹¹C]Methyl triflate ([¹¹C]methyl trifluoromethanesulfonate) was formed in high yield when [¹¹C]methyl iodide in a nitrogen carrier was passed at 200°C through a column containing graphitized carbon impregnated with 50% by weight of silver triflate.

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There are more references available in the full text version of this article.

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Some scientific discoveries are well known only to a core group of researchers working on technical subjects. Nevertheless, they open new research directions, allow existing knowledge to be viewed in entirely new and useful ways, or provide a way to make something that was hard or impossible to make before. Carbon-11 methyl triflate ([¹¹C]MeOTf) is one such advance, facilitating the synthesis of many carbon-11 radio tracers and broadening the range of applications of carbon-11 radiochemistry. The year 2022 marked the 30th anniversary of the original paper in Applied Radiation and Isotopes introducing a simple synthesis of [¹¹C]MeOTf from carbon-11 methyl iodide ([¹¹C]MeI) and it also marked the end of the fruitful career and life of the researcher who developed it, Douglas Jewett. It seems fitting to say a few words on how it came to be and how it has helped advance carbon-11 radiochemistry.
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After introduction of the first commercial combined PET and CT scanner in 2001, this diagnostic tool quickly became a clinical success and was considered the fastest growing diagnostic imaging technology ever. However, this technique is very dependent on the availability of positron emitting isotopes and radiochemistry to incorporate the radioactive isotopes into larger molecules of physiological interest. Within this review article a historical overview starting with the first applications of positron emitting isotopes in the 1930's is presented. Afterwards a more detailed presentation summarizing the physical basis and advancements in cyclotron technology is given. Radiochemical and/or pharmaceutical advancements are presented systematically for the most significant isotopes like ¹⁵O, ¹³N, ¹¹C, ¹⁸F and ⁶⁸Ga Besides these major PET isotopes, advancements of other radio-metals and future perspectives regarding application of new radionuclides will be discussed. Finally, very interesting new and compact accelerator technology and microfluidic chemical reaction approaches will be discussed. Especially, new compact accelerator technology might be new quantum leap within this radiodiagnostic technology and might result in even further prevalence, ultimately envisioned by the dose-on-demand concept that will be briefly discussed.
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Positron emission tomography (PET) predominantly relies on the use of carbon-11 and fluorine-18 radiolabeled pharmaceuticals. The growing interest in the fluorine-18 radionuclide for PET undoubtedly results from its convenient half-life (t_1/2 = 109.8 min) and clean decay profile. The special interest of carbon-11 (t_1/2 = 20.38 min) is due to its prevalence in almost all drug molecules, allowing isotopologue labeling of the bioactive molecule as well as the possibility to radiolabel at different positions. Radiochemistry includes the production of these short-lived radionuclides in a cyclotron and the development of rapid synthetic methods for the introduction of these nuclides into a drug molecule, as well as the development of fast purification, analysis and formulation techniques. Radiochemistry is the driving force in molecular PET imaging and the field is still changing significantly. Radiochemistry of carbon-11 and fluorine-18 is dominated by nucleophilic substitution of a heteroatom with a methylating agent (¹¹CH₃I, ¹¹CH₃OTf) or a good leaving group with a fluoride source (i.e., tosylate, triflate, halogen with [¹⁸F]KF/K₂₂₂ or [¹⁸F]TBAF). In recent years however, radiochemistry has developed immensely with novel reactions and approaches. From cross-coupling reactions, [¹¹C]CO₂ fixation reactions, organolithium reagents, chemical and electrochemical [¹¹C]CO₂ decomposition, ¹¹C-carbonylation reactions, the usage of boronic acid ester and iodonium precursors, ¹⁸F-deoxyfluorination of phenols via Ru π-complexes, fluorodestannylation and preparation of ¹⁸F-building blocks.
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^∗: All correspondence should be addressed to: Douglas Jewett, 3480 Kresge 3, Box 0552, University of Michigan, Ann Arbor, MI 48109, U.S.A.

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International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes

Abstract

References (11)

The preparation of ¹¹C-methyl iodide and its use in the synthesis of ¹¹C-methyl-methionine

Int. J. Appl. Radiat. Isot.

Synthesis of methyl iodide-¹¹C and formaldehyde-¹¹C

Int. J. Appl. Radiat. Isot.

Routine synthesis of N-[¹¹C-Methyl]scopolamine by phosphite mediated reductive methylation with [¹¹C]formaldehyde

Appl. Radiat. Isot.

Alkyltrifluoromethane-sulphonates as alkylating reagents for aromatic compounds

J. Chem. Soc. Perkin Trans I

A simple one-pot apparatus for the production of carbon-11 labeled methyl iodide

J. Nucl. Med.

Cited by (330)

Fully automated production of [<sup>11</sup>C]PiB for clinical use on Trasis-AllinOne synthesizer module

30 years of [<sup>11</sup>C]methyl triflate

DREADD-mediated amygdala activation is sufficient to induce anxiety-like responses in young nonhuman primates

Advancement in Production of Radiotracers

State of the art of radiochemistry for<sup>11</sup>C and<sup>18</sup>F PET tracers

Evidence in primates supporting the use of chemogenetics for the treatment of human refractory neuropsychiatric disorders