Search results for "Schiemann reaction"
showing 2 items of 2 documents
Disorder in the crystals of trans-4-fluoroazoxybenzene. Synthesis, spectral properties, crystal structures and DFT calculations
2005
Abstract Two crystals of trans-4-fluoroazoxybenzene were obtained using two different methods. Oxidation of 4-fluoroazobenzene provided crystals of trans-4-fluoroazoxybenzene (I) consisting of two isomers; 51% α (ONN) and 49% β (NNO) isomer. From trans-amino-azoxybenzenes in Schiemann reaction it were obtained crystals of trans-4-fluoro-NNO-azoxybenzenes (II, β isomer) containing 4.7% of the α-isomer according to the HPLC analysis. The crystal structures of I and II were determined by the X-ray diffraction method. In the crystal I two nitrogen atoms of azoxy bridge and fluorine atom are disordered. In the crystal II, there are two independent molecules of trans-4-fluoroazoxybenzene; the mol…
No carrier-added nucleophilic aromatic radiofluorination using solid phase supported arenediazonium sulfonates and 1-(aryldiazenyl)piperazines
2012
Abstract This Letter concerns the investigation of a solid phase based method for no carrier-added nucleophilic [ 18 F]fluorination of aromatic compounds via de-diazofluorination. Initial screening of reaction conditions was conducted using soluble analogues, that is, substituted benzenediazonium tosylates and 1-(phenyldiazenyl)piperazines in solution. This was followed by translation of the principle conditions to solid phase bound analogues. A variety of substituted aryldiazonium cations were immobilised using a sulfonate functionalised ion exchange resin and labelled with [ 18 F]fluoride ion by Balz–Schiemann like thermal decomposition in the presence of no carrier-added [ 18 F]fluoride …