Comparison of pathways to the versatile synthon of no‐carrier‐added 1‐bromo‐4‐[¹⁸F]fluorobenzene

Abstract

SummaryThe availability of no-carrier-added (n.c. [ 18 F]fluoride were examined. Of six pathways compared, symmetrical bis-(4-bromphenyl)iodonium bromide proved most useful to achieve the title compound in a direct, one-step nucleophilic substitution with a radiochemical yield (RCY) of 65% within 10 min.

Batch‐mode microfluidic radiosynthesis of N‐succinimidyl‐4‐[18F]fluorobenzoate for protein labelling

“…16,17 Step (3). After completion of the fluorination step, an aqueous solution of tetra-n-isopropylammonium hydroxide (10 mL) was added to the micro-reactor leading to a total volume of 50 mL (Figure 3(D)).…”

Radical scavengers: A practical solution to the reproducibility issue in the fluoridation of diaryliodonium salts

“…These benefits have resulted in much recent interest in diaryliodonium salts as precursors to fluorine-18 arenes [10][11][12][13][14][15][16], however we, and others [12,16], have observed that the fluoridation results can be extremely variable, particularly in the case of electron-rich diaryliodonium salts. Despite the potential benefits the approach has for the introduction of fluorine-18 into aromatic systems the associated lack of reproducibility has severely limited the development and application of this approach to the production of fluorine-18 labelled radiopharmaceuticals.…”

Competitive demethylation and substitution in N,N,N-trimethylanilinium fluorides

“…Corrected radiofluorination yields for para-trimethylammonium aryl aldehydes [24][25][26][27], ketones [28][29][30][31][32], and esters [33][34][35][36] range from excellent (80%) for aryl aldehydes to fair (50%) for aryl esters. For relatively unactivated rings, fluorodeamination is difficult; Ermert and coworkers [37] studied substitution in 4-bromo-N,N,N-trimethylanilinium triflates and found that only 8-12% yields of the desired 4-fluorobromobenzenes were obtained under optimized conditions.…”