- Synthesis and Adrenergic Activity of Ring-Fluorinated Phenylephrines
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2-Fluoro-, 4-fluoro-, and 6-fluorophenylephrine (6-FPE) were synthesized from the corresponding fluorinated 3-hydroxybenzaldehydes.New routes to 2-fluoro- and 6-fluoro-3-hydroxybenzaldehydes were developed based on regioselective lithiation of 2- and 4-fluorobenzene ortho to fluorine.As with norepinephrine and isoproterenol analogues, the adrenergic properties of phenylephrine were markedly altered by ring fluorination.The order of potency of the fluoro analogues as α1-adrenergic agonists in the stimulation of contraction of aorticstrips and of phosphatidylinositol turnover and potentiation of cyclic AMP accumulation in guinea pig synaptoneurosomes was 6-FPE > PE > 4-FPE > 2-FPE.The same pattern was observed for the displacement of radioligands specific for α1- and α2-adrenergic receptors on brain membranes.The order of potency for the displacement of 3H>dihydroalprenolol, a β-specific adrenergic ligand from brain membranes, was 2-FPE > 4-FPE = PE >> 6-FPE. 6-FPE was much more selective for α-adrenergic receptors compared to β-receptors than was phenylephrine.A rationale for the observed fluorine-induced alterations in potency and selectivity of the FPEs for α- and β-adrenergic systems is presented based on fluorine-induced conformations due to electrostatic repulsion of fluorine and the benzyl hydroxyl group.
- Kirk, Kenneth L.,Olubajo, Olarangbe,Buchhold, Konstantin,Lewandowski, Gail A.,Gusovsky, Fabian,et al.
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- A convenient route to new fluorinated photodynamic therapeutic photosensitizers based on meso-tetra(hydroxyphenyl)porphyrins
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A general synthetic route was developed for the synthesis of new fluorinated tetra(hydroxyphenyl) porphyrins [5,10,15,20-tetrakis(2-fluoro-3-hydroxyphenyl)porphyrin 10, 5,10,15,20-tetrakis(2,4-difluoro-3-hydroxyphenyl)porphyrin 11, and 5,10,15,20-tetrakis(3,5-difluoro-4-hydroxyphenyl)porphyrin 12], analogues of sensitisers 1-3 which are known to be active in vivo in cancer photodynamic therapy.
- Songca, Sandile P.,Bonnett, Raymond,Maes, Catherine M.
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