A Cu(I)-mediated
fluoro-deamination method for nucleophilic radiofluorination
was devised. The method affords fluorinated aromatic products directly
from anilines under both no-carrier added and stoichiometric conditions.
Isolated radiochemical yields range from 11% to 81% with high radiochemical
purities and a molar activity of 58 MBq/nmol. The reaction conditions
were implemented successfully in an automated process for production
of (
S
)-4[
18
F]fluorogluthetimide on a radiosynthesis
module.
A metal free, phosphane-catalysed protocol for C-F bond formation based on ipso-elimination of iodanes is described. The reaction proceeds in significantly higher yield and with markedly reduced variability of yields (yield range) than previously described procedures. Rapid and efficient radiofluorination is achieved using unobjectionable chemical reagents with precedence in routine radiotracer production. With operational ease and mild conditions, the method promises a high potential for radiolabelling of biomolecules.
Racemates of hydrophobic amino acids with linear side chains are known to undergo a unique series of solid-state phase transitions that involve sliding of molecular bilayers upon heating or cooling. Recently, this behaviour was shown to extend also to quasiracemates of two different amino acids with opposite handedness [Görbitz & Karen (2015). J. Phys. Chem. B, 119, 4975-4984]. Previous investigations are here extended to an L-2-aminobutyric acid-D-methionine (1/1) co-crystal, C4H9NO2·C5H11NO2S. The significant difference in size between the -CH2CH3 and -CH2CH2SCH3 side chains leads to extensive disorder at room temperature, which is essentially resolved after a phase transition at 229 K to an unprecedented triclinic form where all four D-methionine molecules in the asymmetric unit have different side-chain conformations and all three side-chain rotamers are used for the four partner L-2-aminobutyric acid molecules.
We developed a versatile, rapid, and robust high‐yielding radiochemistry‐adapted protocol utilizing formamides as masking groups for secondary and tertiary amines. Selective reducing conditions were devised using borane reagents. In this protocol formamide functionalities were found to have an orthogonal reactivity to most other carbonyl functions, while effectively protecting amines from oxidative degradation. We exemplify the newly developed methodology by synthesizing a µ‐opioid PET radiotracer and a phenethylamine PET radiotracer analogue.
Herein, we report a method for the isotopic labelling of hydantoins directly from CO2 by means of trimethyl-λ5-phosphine diiodide mediated carbonyl insertion. The method is suitable for 13C-labelling of diverse...
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