Tetrabutylammonium tosylate as inert phase-transfer catalyst: The key to high efficiency SN2 radiofluorinations

Orlovskaya, Viktoriya V.; Antuganov, Dmitrii; Федорова, О. С.; Timofeev, Vasilii; Красикова, Р. Н.

doi:10.1016/j.apradiso.2020.109195

Cited by 21 publications

(29 citation statements)

References 36 publications

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“…Based on those findings and our recent experience in the use of alkylammoinum sulfonates as effective catalysts of the aliphatic radiofluorination [ 14 ] we have proposed to replace basic Et 4 NHCO 3 with a neutral Bu 4 NOTf in conjunction with 2‐PrOH as the eluting solvent. Preliminary studies have revealed that Bu 4 NOTf/2‐PrOH is an effective catalyst for the preparation of 6‐[ 18 F]fluoro‐L‐ m ‐tyrosine via Cu‐mediated radiofluorination of BPin‐substituted Ni‐BPB‐AA complex.…”

Section: Resultsmentioning

confidence: 99%

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis

et al. 2020

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Cu‐mediated radiofluorination of arylboronic acid pinacol esters (ArylBPin) using Cu(OTf)2(Py)4 complex is a useful approach for the introduction of [18F]fluorine into non‐activated arenes and heteroarenes. Owing to the complexity of the mechanism and wide variation in substrate reactivity the choice of reaction conditions must be made individually for every precursor. Careful selection of phase‐transfer catalysts also plays a role, as Cu‐catalyst and ArylBPin precursors are known to be unstable in basic conditions. Using tetrabutylammonium triflate alcohol solution for elution of [18F]fluoride from ion‐exchange cartridge and employing same alcohol as a co‐solvent in the following labelling step, we have developed a general protocol resulting in >80 % fluorination efficiency of ArylBPin precursors for 4‐[18F]fluoro‐D,L‐phenylalanine and 6‐L‐[18F]FDOPA. Radiofluorination in neat alcohol was particularly effective for the synthesis of 6‐L‐[18F]FDOPA, allowing for substantial increase of yield and decrease of synthesis time compared to current methods (activity yield 14.5 ± 0.5 %, 70 min synthesis time).

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Section: Resultsmentioning

confidence: 99%

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis

et al. 2020

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“…Tetrabutylammonium tosylate (TBAOTs) is described as an inert phase-transfer catalyst (PTC) for aliphatic S N 2 radiofluorinations with some examples of commonly used fluorine-18 radiotracers (Orlovskaya et al, 2020). A unique methodology is presented clearly pointing out its advantages for the 18 F-fluorinations as they show downscaling .…”

Section: By Ana Reymentioning

confidence: 99%

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

Aime¹,

Al‐Qahtani

Béhé

et al. 2021

EJNMMI radiopharm. chem.

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Background The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biyearly highlight commentary to update the readership on trends in the field of radiopharmaceutical development. Results This commentary of highlights has resulted in 23 different topics selected by each member of the Editorial Board addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals. Conclusion Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field being the scope of EJNMMI Radiopharmacy and Chemistry.

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“…16 This method could provide processed 18 F from the QMA cartridge with high elution efficiency and could be used to synthesize several radiotracers in good to excellent radiochemical yields. However, the technique suffered a significant drawback: the aqueous 18 F needed to be loaded onto the cartridge in the reverse direction to ensure maximal elution efficiency. This "back-flushing" procedure adds operational complexity and increases the probability of introducing radiochemical impurities from the irradiated cyclotron target water into the reactor vessel.…”

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confidence: 99%

“…Experiments to test both the18 F elution efficiency and the QMA eluent mixture's effect on CMRF reaction performance of various 18 F processing methods. standard published QMA processing methods (Table1, entries 1-2) yielded good recoveries of [ 18 F]fluoride; however, as expected, the model CMRF reactions did not tolerate the presence of kryptofix and potassium carbonate.…”

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confidence: 99%

Scalable 18F Processing Conditions for Copper-Mediated Radiofluorination Chemistry Facilitate "Design of Experiments" (DoE) Optimization Studies and Afford an Improved Synthesis of [18F]Olaparib.

Bowden¹,

Chailanggar²,

Pichler³

et al. 2021

Preprint

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A convenient, scalable, and azeotropic drying free method for processing [18F]fluoride as base free [18F]TBAF is reported and applied to copper-mediated radiofluorination (CMRF) radiosyntheses. A central feature of this method is that a single production of [18F]TBAF can be divided into small aliquots that can be used to perform multiple small-scale reactions in DoE optimization studies. The results of these studies can then be reliably translated to full batch tracer productions using automated synthesizers. This processing technique was successfully applied to the manual DoE optimization, DoE study validation, and subsequent full-batch automation of the PARP-1 tracer [18F]olaparib. After DoE optimization, we were able to produce [18F]olaparib in high radiochemical yields via both manual (%RCY (CMRF step only) = 78 ± 6 %, n = 4) and automated (up to 80% radiochemical yield (%RCY); 41% activity yield (%AY)) radiosynthesis procedures. This work further demonstrates the power of the DoE approach for improving the radiochemical yields and radiosynthesis performance of clinically relevant tracer productions

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Tetrabutylammonium tosylate as inert phase-transfer catalyst: The key to high efficiency SN2 radiofluorinations

Cited by 21 publications

References 36 publications

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

Scalable 18F Processing Conditions for Copper-Mediated Radiofluorination Chemistry Facilitate "Design of Experiments" (DoE) Optimization Studies and Afford an Improved Synthesis of [18F]Olaparib.

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Tetrabutylammonium tosylate as inert phase-transfer catalyst: The key to high efficiency SN2 radiofluorinations

Cited by 21 publications

References 36 publications

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[18F]FDOPA Synthesis

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[18F]FDOPA Synthesis

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

Scalable 18F Processing Conditions for Copper-Mediated Radiofluorination Chemistry Facilitate "Design of Experiments" (DoE) Optimization Studies and Afford an Improved Synthesis of [18F]Olaparib.

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Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis

Cu‐Mediated Radiofluorination of Aryl Pinacolboronate Esters: Alcohols as Solvents with Application to 6‐L‐[¹⁸F]FDOPA Synthesis