Monofluorinated analogues of polychlorinated biphenyls (F-PCBs): synthesis using the Suzuki-coupling, characterization, specific properties and intended use.
An improved method, a palladium-catalyzed cross-coupling reaction the so-called Suzuki-coupling, was used to synthesize 19 monofluorinated analogues (F-PCBs) of polychlorinated biphenyls (PCBs), including analogues of PCBs 28, 52 and 81. The coupling of chlorinated and/or fluorinated isomers of aryl boronic acids with bromo- and/or iodobenzenes gave the desired F-PCB congeners in good to excellent yields. The self-coupling product of the aryl boronic acids was the major impurity, but this limitation could be minimized. The influence of ortho-substitution by chlorine on the reaction time was studied in detail. The F-PCBs were characterized by means of 1H and 19F NMR and mass spectrometry (MS). F-PCBs show remarkably similar characteristics in many aspects to those of the corresponding non-fluorinated parent PCBs. Since fluorine is generally resistant to degradation, once incorporated into a substrate it functions as an indelible label that can be used to monitor structures and dynamics. F-PCBs may prove their usefulness as markers and tracers in mechanistic and toxicological studies. The aim of further research will be to test the suitability of fluorine as a sensitive probe in a broad range of applications, including synthesis, analytical, mechanistic and toxicological studies.
Luthe
Gregor M
GM
Institute of Chemistry, Norwegian University of Science and Technology, N-7041 Trondheim, Norway. gregor-luthe@uiowa.edu
Schut
Benjamin G
BG
Aaseng
Jon Erik
JE
D004785:Environmental Pollutants / Q000138:chemical synthesis* / Q000737:chemistry; D013058:Mass Spectrometry; D010165:Palladium / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000138:chemical synthesis* / Q000737:chemistry
D004785:Environmental Pollutants; D010165:Palladium; D011078:Polychlorinated Biphenyls